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Multidrug-resistant bacteria represent one of the most important health care problems worldwide. While there are numerous drugs available for standard therapy, there are only a few compounds capable of serving as a last resort for severe infections. Therefore, approaches to control multidrug-resistant bacteria must be implemented. Here, a strategy of reactivating the established glycopeptide antibiotic vancomycin by structural modification with polycationic peptides and subsequent fatty acid conjugation to overcome the resistance of multidrug-resistant bacteria was followed. This study especially focuses on the structure–activity relationship, depending on the modification site and fatty acid chain length. The synthesized conjugates showed high antimicrobial potential on vancomycin-resistant enterococci. We were able to demonstrate that the antimicrobial activity of the vancomycin-lipopeptide conjugates depends on the chain length of the attached fatty acid. All conjugates showed good cytocompatibility in vitro and in vivo. Radiolabeling enabled the in vivo determination of pharmacokinetics in Wistar rats by molecular imaging and biodistribution studies. An improved biodistribution profile in comparison to unmodified vancomycin was observed. While vancomycin is rapidly excreted by the kidneys, the most potent conjugate shows a hepatobiliary excretion profile. In conclusion, these results demonstrate the potential of the structural modification of already established antibiotics to provide highly active compounds for tackling multidrug-resistant bacteria.
More recently, it became clear that conclusions drawn from traditional ecological theory may be altered substantially if the spatial dimension of species interactions is considered explicitly. Regardless of the details of these models, spatially explicit simulations of ecological processes have nearly universally shown that spatial or spatio-temporal patterns in species distributions can emerge even from homogeneous starting conditions; limited dispersal is one of the key factors responsible for the development of such aggregated and patchy distributions (cf., Pacala 1986, Holmes et al. 1994, Molofsky 1994, Tilman 1994, Bascompte and Sole 1995, 1997, 1998, Jeltsch et al. 1999). In line with these ideas, we wish to draw attention to the fact that in heterogeneous landscapes differences in characteristic dispersal distances between species are a sufficient precondition for the emergence of a successional pattern. We will use a simple, spatially explicit simulation program to demonstrate the validity of this statement. We will also show that the speed of the successional progress depends on scale and heterogeneity in the distribution of suitable habitat.
Background
The aim of this study was to quantify the variability in spinal radiosurgery (SRS) planning practices between five international institutions, all member of the Elekta Spine Radiosurgery Research Consortium.
Methods
Four institutions provided one representative patient case each consisting of the medical history, CT and MR imaging. A step-wise planning approach was used where, after each planning step a consensus was generated that formed the basis for the next planning step. This allowed independent analysis of all planning steps of CT-MR image registration, GTV definition, CTV definition, PTV definition and SRS treatment planning. In addition, each institution generated one additional SRS plan for each case based on intra-institutional image registration and contouring, independent of consensus results.
Results
Averaged over the four cases, image registration variability ranged between translational 1.1 mm and 2.4 mm and rotational 1.1° and 2.0° in all three directions. GTV delineation variability was 1.5 mm in axial and 1.6 mm in longitudinal direction averaged for the four cases. CTV delineation variability was 0.8 mm in axial and 1.2 mm in longitudinal direction. CTV-to-PTV margins ranged between 0 mm and 2 mm according to institutional protocol. Delineation variability was 1 mm in axial directions for the spinal cord. Average PTV coverage for a single fraction18 Gy prescription was 87 ± 5 %; Dmin to the PTV was 7.5 ± 1.8 Gy averaged over all cases and institutions. Average Dmax to the PRV_SC (spinal cord + 1 mm) was 10.5 ± 1.6 Gy and the average Paddick conformity index was 0.69 ± 0.06.
Conclusions
Results of this study reflect the variability in current practice of spine radiosurgery in large and highly experienced academic centers. Despite close methodical agreement in the daily workflow, clinically significant variability in all steps of the treatment planning process was demonstrated. This may translate into differences in patient clinical outcome and highlights the need for consensus and established delineation and planning criteria.
Background
Although 5-HTTLPR has been shown to influence the risk of life stress-induced depression in the majority of studies, others have produced contradictory results, possibly due to weak effects and/or sample heterogeneity.
Methods
In the present study we investigated how age, type and intensity of life-stressors modulate the effect of 5-HTTLPR on depression and anxiety in a European population cohort of over 2300 subjects. Recent negative life events (RLE), childhood adversity (CHA), lifetime depression, Brief Symptoms Inventory (BSI) depression and anxiety scores were determined in each subject. Besides traditional statistical analysis we calculated Bayesian effect strength and relevance of 5-HTTLPR genotypes in specified models.
Results
The short (s) low expressing allele showed association with increased risk of depression related phenotypes, but all nominally significant effects would turn to non-significant after correction for multiple testing in the traditional analysis. Bayesian effect strength and relevance analysis, however, confirmed the role of 5-HTTLPR. Regarding current (BSI) and lifetime depression 5-HTTLPR-by-RLE interactions were confirmed. Main effect, with other words direct association, was supported with BSI anxiety. With more frequent RLE the prevalence or symptoms of depression increased in ss carriers. Although CHA failed to show an interaction with 5-HTTLPR, in young subjects CHA sensitized towards the depression promoting effect of even mild RLE. Furthermore, the direct association of anxiety with the s allele was driven by young (\(\leq\)30) individuals.
Limitations
Our study is cross-sectional and applies self-report questionnaires.
Conclusions
Albeit 5-HTTLPR has only weak/moderate effects, the s allele is directly associated with anxiety and modulates development of depression in homogeneous subgroups.
Objectives
To determine sleep bruxism (SB) behavior during five consecutive nights and to identify correlations between SB episodes per hour (SB index) and sleep-time masseter-muscle activity (sMMA).
Material and methods
Thirty-one participants were included in the study. Of these, 10 were classified as sleep bruxers (group SB-1) and nine as non-sleep bruxers (group non-SB). The bruxism status of these 19 patients was identified by means of questionnaires, an assessment of clinical symptoms, and electromyographic/electrocardiographic data (Bruxoff® device). The remaining 12 participants were also identified as bruxers, but based exclusively on data from the Bruxoff device (group SB-2). Data analysis included descriptive statistics and Spearman’s correlation to assess the relationship between the SB index and sMMA.
Results
Participants in group SB-1 showed an overall mean SB index of 3.1 ± 1.6 and a mean total sMMA per night of 62.9 ± 38.3. Participants in group SB-2 had an overall mean SB index of 2.7 ± 1.5 and a mean total sMMA of 56.0 ± 29.3. In the non-SB group, participants showed an overall mean SB index of 0.8 ± 0.5 and a mean total sMMA of 56.8 ± 30.3. Spearman’s correlation yielded values of − 0.27 to 0.71 for the correlation between sMMA and SB index.
Conclusions
The data revealed variable SB activity and the absence of a reliable correlation between sMMA and the SB index.
Clinical relevance
The high variation in SB activity and lack of correlation between sMMA and the SB index should be considered when diagnosing SB.
Trial registration
Clinical Trials [NIH], clinical trial no. NCT03039985.
Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The factors driving this variation in nectar quality are still largely unclear.
We investigated factors underlying interspecific variation in macronutrient composition of floral nectar in 34 different grassland plant species. Specifically, we tested for correlations between the phylogenetic relatedness and morphology of plants and the carbohydrate (C) and total amino acid (AA) composition and C:AA ratios of nectar.
We found that compositions of carbohydrates and (essential) amino acids as well as C:AA ratios in nectar varied significantly within and between plant species. They showed no clear phylogenetic signal. Moreover, variation in carbohydrate composition was related to family‐specific structural characteristics and combinations of morphological traits. Plants with nectar‐exposing flowers, bowl‐ or parabolic‐shaped flowers, as often found in the Apiaceae and Asteraceae, had nectar with higher proportions of hexoses, indicating a selective pressure to decelerate evaporation by increasing nectar osmolality.
Our study suggests that variation in nectar nutrient composition is, among others, affected by family‐specific combinations of morphological traits. However, even within species, variation in nectar quality is high. As nectar quality can strongly affect visitation patterns of pollinators and thus pollination success, this intra‐ and interspecific variation requires more studies to fully elucidate the underlying causes and the consequences for pollinator behaviour.
This doctoral thesis is concerned with the mathematical modeling of magnetoelastic materials and the analysis of PDE systems describing these materials and obtained from a variational approach.
The purpose is to capture the behavior of elastic particles that are not only magnetic but exhibit a magnetic domain structure which is well described by the micromagnetic energy and the Landau-Lifshitz-Gilbert equation of the magnetization. The equation of motion for the material’s velocity is derived in a continuum mechanical setting from an energy ansatz. In the modeling process, the focus is on the interplay between Lagrangian and Eulerian coordinate systems to combine elasticity and magnetism in one model without the assumption of small deformations.
The resulting general PDE system is simplified using special assumptions. Existence of weak solutions is proved for two variants of the PDE system, one including gradient flow dynamics on the magnetization, and the other featuring the Landau-Lifshitz-Gilbert equation. The proof is based on a Galerkin method and a fixed point argument. The analysis of the PDE system with the Landau-Lifshitz-Gilbert equation uses a more involved approach to obtain weak solutions based on G. Carbou and P. Fabrie 2001.
Many modern statistically efficient methods come with tremendous computational challenges, often leading to large-scale optimisation problems. In this work, we examine such computational issues for recently developed estimation methods in nonparametric regression with a specific view on image denoising. We consider in particular certain variational multiscale estimators which are statistically optimal in minimax sense, yet computationally intensive. Such an estimator is computed as the minimiser of a smoothness functional (e.g., TV norm) over the class of all estimators such that none of its coefficients with respect to a given multiscale dictionary is statistically significant. The so obtained multiscale Nemirowski-Dantzig estimator (MIND) can incorporate any convex smoothness functional and combine it with a proper dictionary including wavelets, curvelets and shearlets. The computation of MIND in general requires to solve a high-dimensional constrained convex optimisation problem with a specific structure of the constraints induced by the statistical multiscale testing criterion. To solve this explicitly, we discuss three different algorithmic approaches: the Chambolle-Pock, ADMM and semismooth Newton algorithms. Algorithmic details and an explicit implementation is presented and the solutions are then compared numerically in a simulation study and on various test images. We thereby recommend the Chambolle-Pock algorithm in most cases for its fast convergence. We stress that our analysis can also be transferred to signal recovery and other denoising problems to recover more general objects whenever it is possible to borrow statistical strength from data patches of similar object structure.
Acceleration is a central aim of clinical and technical research in magnetic resonance imaging (MRI) today, with the potential to increase robustness, accessibility and patient comfort, reduce cost, and enable entirely new kinds of examinations. A key component in this endeavor is image reconstruction, as most modern approaches build on advanced signal and image processing. Here, deep learning (DL)-based methods have recently shown considerable potential, with numerous publications demonstrating benefits for MRI reconstruction. However, these methods often come at the cost of an increased risk for subtle yet critical errors. Therefore, the aim of this thesis is to advance DL-based MRI reconstruction, while ensuring high quality and fidelity with measured data. A network architecture specifically suited for this purpose is the variational network (VN). To investigate the benefits these can bring to non-Cartesian cardiac imaging, the first part presents an application of VNs, which were specifically adapted to the reconstruction of accelerated spiral acquisitions. The proposed method is compared to a segmented exam, a U-Net and a compressed sensing (CS) model using qualitative and quantitative measures. While the U-Net performed poorly, the VN as well as the CS reconstruction showed good output quality. In functional cardiac imaging, the proposed real-time method with VN reconstruction substantially accelerates examinations over the gold-standard, from over 10 to just 1 minute. Clinical parameters agreed on average.
Generally in MRI reconstruction, the assessment of image quality is complex, in particular for modern non-linear methods. Therefore, advanced techniques for precise evaluation of quality were subsequently demonstrated.
With two distinct methods, resolution and amplification or suppression of noise are quantified locally in each pixel of a reconstruction. Using these, local maps of resolution and noise in parallel imaging (GRAPPA), CS, U-Net and VN reconstructions were determined for MR images of the brain. In the tested images, GRAPPA delivers uniform and ideal resolution, but amplifies noise noticeably. The other methods adapt their behavior to image structure, where different levels of local blurring were observed at edges compared to homogeneous areas, and noise was suppressed except at edges. Overall, VNs were found to combine a number of advantageous properties, including a good trade-off between resolution and noise, fast reconstruction times, and high overall image quality and fidelity of the produced output. Therefore, this network architecture seems highly promising for MRI reconstruction.
Background
In 2004, routine varicella vaccination was recommended in Germany for children 11-14 months of age with one dose, and since 2009, with a second dose at 15-23 months of age. The effects on varicella epidemiology were investigated.
Methods
Data on varicella vaccinations, cases and complications were collected from annual parent surveys (2006-2011), monthly paediatric practice surveillance (Oct 2006 - Sep 2011; five varicella seasons) and paediatric hospital databases (2005-2009) in the area of Munich (about 238,000 paediatric inhabitants); annual incidences of cases and hospitalisations were estimated.
Results
Varicella vaccination coverage (1st dose) in children 18-36 months of age increased in two steps (38%, 51%, 53%, 53%, 66% and 68%); second-dose coverage reached 59% in the 2011 survey. A monthly mean of 82 (62%) practices participated; they applied a total of 50,059 first-dose and 40,541 second-dose varicella vaccinations, with preferential use of combined MMR-varicella vaccine after recommendation of two doses, and reported a total of 16,054 varicella cases <17 years of age. The mean number of cases decreased by 67% in two steps, from 6.6 (95%CI 6.1-7.0) per 1,000 patient contacts in season 2006/07 to 4.2 (95%CI 3.9-4.6) in 2007/08 and 4.0 (95%CI 3.6-4.3) in 2008/09, and further to 2.3 (95%CI 2.0-2.6) in 2009/10 and 2.2 (95%CI 1.9-2.5) in 2010/11. The decrease occurred in all paediatric age groups, indicating herd protection effects. Incidence of varicella was estimated as 78/1,000 children <17 years of age in 2006/07, and 19/1,000 in 2010/11. Vaccinated cases increased from 0.3 (95%0.2-0.3) per 1,000 patient contacts in 2006/07 to 0.4 (95%CI 0.3-0.5) until 2008/09 and decreased to 0.2 (95%CI 0.2-0.3) until 2010/11. The practices treated a total of 134 complicated cases, mainly with skin complications. The paediatric hospitals recorded a total of 178 varicella patients, including 40 (22.5%) with neurological complications and one (0.6%) fatality due to varicella pneumonia. Incidence of hospitalisations decreased from 7.6 per 100,000 children <17 years of age in 2005 to 4.3 in 2009, and from 21.0 to 4.7 in children <5 years of age.
Conclusions
Overall, the results show increasing acceptance and a strong impact of the varicella vaccination program, even with still suboptimal vaccination coverage.
Varicella-zoster virus infections in immunocompromised patients - a single centre 6-years analysis
(2011)
Background: Infection with varicella-zoster virus (VZV) contemporaneously with malignant disease or immunosuppression represents a particular challenge and requires individualized decisions and treatment. Although the increasing use of varicella-vaccines in the general population and rapid initiation of VZVimmunoglobulins and acyclovir in case of exposure has been beneficial for some patients, immunocompromised individuals are still at risk for unfavourable courses. Methods: In this single center, 6-year analysis we review incidence, hospitalization and complication rates of VZVinfections in our center and compare them to published data. Furthermore, we report three instructive cases. Results: Hospitalization rate of referred children with VZV-infections was 45%, among these 17% with malignancies and 9% under immunosuppressive therapy. Rate of complications was not elevated in these two high-risk cohorts, but one ALL-patient died due to VZV-related complications. We report one 4-year old boy with initial diagnosis of acute lymphoblastic leukemia who showed a rapidly fatal outcome of his simultaneous varicella-infection, one 1.8-year old boy with an identical situation but a mild course of his disease, and an 8.5-year old boy with a steroiddependent nephrotic syndrome. This boy developed severe hepatic involvement during his varicella-infection but responded to immediate withdrawl of steroids and administration of acyclovir plus single-dose cidofovir after nonresponse to acyclovir after 48 h. Conclusion: Our data show that patients with malignant diseases or immunosuppressive therapy should be hospitalized and treated immediately with antiviral agents. Despite these measures the course of VZV-infections can be highly variable in these patients. We discuss aids to individual decision-making for these difficult situations.
Variability of gene expression due to stochasticity of transcription or variation of extrinsic signals, termed biological noise, is a potential driving force of cellular differentiation. Utilizing single-cell RNA-sequencing, we develop VarID2 for the quantification of biological noise at single-cell resolution. VarID2 reveals enhanced nuclear versus cytoplasmic noise, and distinct regulatory modes stratified by correlation between noise, expression, and chromatin accessibility. Noise levels are minimal in murine hematopoietic stem cells (HSCs) and increase during differentiation and ageing. Differential noise identifies myeloid-biased Dlk1+ long-term HSCs in aged mice with enhanced quiescence and self-renewal capacity. VarID2 reveals noise dynamics invisible to conventional single-cell transcriptome analysis.
Mutations in mitochondrial aminoacyl-tRNA synthetases (mtARSs) have been reported in patients with mitochondriopathies: most commonly encephalopathy, but also cardiomyopathy. Through a GWAS, we showed possible associations between mitochondrial valyl-tRNA synthetase (VARS2) dysregulations and non-ischemic cardiomyopathy. We aimed to investigate the possible consequences of VARS2 depletion in zebrafish and cultured HEK293A cells. Transient VARS2 loss-of-function was induced in zebrafish embryos using Morpholinos. The enzymatic activity of VARS2 was measured in VARS2-depleted cells via northern blot. Heterozygous VARS2 knockout was established in HEK293A cells using CRISPR/Cas9 technology. BN-PAGE and SDS-PAGE were used to investigate electron transport chain (ETC) complexes, and the oxygen consumption rate and extracellular acidification rate were measured using a Seahorse XFe96 Analyzer. The activation of the integrated stress response (ISR) and possible disruptions in mitochondrial fatty acid oxidation (FAO) were explored using RT-qPCR and western blot. Zebrafish embryos with transient VARS2 loss-of-function showed features of heart failure as well as indications of CNS and skeletal muscle involvements. The enzymatic activity of VARS2 was significantly reduced in VARS2-depleted cells. Heterozygous VARS2-knockout cells showed a rearrangement of ETC complexes in favor of complexes III\(_2\), III\(_2\) + IV, and supercomplexes without significant respiratory chain deficiencies. These cells also showed the enhanced activation of the ISR, as indicated by increased eIF-2α phosphorylation and a significant increase in the transcript levels of ATF4, ATF5, and DDIT3 (CHOP), as well as disruptions in FAO. The activation of the ISR and disruptions in mitochondrial FAO may underlie the adaptive changes in VARS2-depleted cells.
Objectives
Vessel wall enhancement (VWE) may be commonly seen on MRI images of asymptomatic subjects. This study aimed to characterize the VWE of the proximal internal carotid (ICA) and vertebral arteries (VA) in a non-vasculitic elderly patient cohort.
Methods
Cranial MRI scans at 3 Tesla were performed in 43 patients (aged ≥ 50 years) with known malignancy for exclusion of cerebral metastases. For vessel wall imaging (VWI), a high-resolution compressed-sensing black-blood 3D T1-weighted fast (turbo) spin echo sequence (T1 CS-SPACE prototype) was applied post gadolinium with an isotropic resolution of 0.55 mm. Bilateral proximal intradural ICA and VA segments were evaluated for presence, morphology, and longitudinal extension of VWE.
Results
Concentric VWE of the proximal intradural ICA was found in 13 (30%) patients, and of the proximal intradural VA in 39 (91%) patients. Mean longitudinal extension of VWE after dural entry was 13 mm in the VA and 2 mm in the ICA. In 14 of 39 patients (36%) with proximal intradural VWE, morphology of VWE was suggestive of the mere presence of vasa vasorum. In 25 patients (64 %), morphology indicated atherosclerotic lesions in addition to vasa vasorum.
Conclusions
Vasa vasorum may account for concentric VWE within the proximal 2 mm of the ICA and 13 mm of the VA after dural entry in elderly subjects. Concentric VWE in these locations should not be confused with large artery vasculitis. Distal to these segments, VWE may be more likely related to pathologic conditions such as vasculitis.
Background
The vascular type represents a very rare, yet the clinically most fatal entity of Ehlers-Danlos syndrome (EDS). Patients are often admitted due to arterial bleedings and the friable tissue and the altered coagulation contribute to the challenge in treatment strategies. Until now there is little information about clotting characteristics that might influence hemostasis decisively and eventually worsen emergency situations.
Results
22 vascular type EDS patients were studied for hemoglobin, platelet volume and count, Quick and activated partial thromboplastin time, fibrinogen, factor XIII, von Willebrand disease, vitamin D and platelet aggregation by modern standard laboratory methods. Results show a high prevalence of over 50 % for platelet aggregation disorders in vascular type EDS patients, especially for collagen and epinephrine induced tests, whereas the plasmatic cascade did not show any alterations. Additionally, more than half of the tested subjects showed low vitamin D serum levels, which might additionally affect vascular wall integrity.
Conclusion
The presented data underline the importance of detailed laboratory screening methods in vascular type EDS patients in order to allow for targeted application of platelet-interacting substances that might be of decisive benefit in the emergency setting.
Malignant melanoma (MM) is the most dangerous type of skin cancer with rising incidences worldwide. Melanoma skin models can help to elucidate its causes and formation or to develop new treatment strategies. However, most of the current skin models lack a vasculature, limiting their functionality and applicability. MM relies on the vascular system for its own supply and for its dissemination to distant body sites via lymphatic and blood vessels. Thus, to accurately study MM progression, a functional vasculature is indispensable. To date, there are no vascularized skin models to study melanoma metastasis in vitro, which is why such studies still rely on animal experimentation.
In the present thesis, two different approaches for the vascularization of skin models are employed with the aim to establish a vascularized 3D in vitro full-thickness skin equivalent (FTSE) that can serve as a test system for the investigation of the progression of MM.
Initially, endothelial cells were incorporated in the dermal part of FTSEs. The optimal seeding density, a spheroid conformation of the cells and the cell culture medium were tested. A high cell density resulted in the formation of lumen-forming shapes distributed in the dermal part of the model. These capillary-like structures were proven to be of endothelial origin by staining for the endothelial cell marker CD31. The established vascularized FTSE (vFTSE) was characterized histologically after 4 weeks of culture, revealing an architecture similar to human skin in vivo with a stratified epidermis, separated from the dermal equivalent by a basement membrane indicated by collagen type IV. However, this random capillary-like network is not functional as it cannot be perfused.
Therefore, the second vascularization approach focused on the generation of a perfusable tissue construct. A channel was molded within a collagen hydrogel and seeded with endothelial cells to mimic a central, perfusable vessel. The generation and the perfusion culture of the collagen hydrogel was enabled by the use of two custom-made, 3D printed bioreactors. Histological assessment of the hydrogels revealed the lining of the channel with a monolayer of endothelial cells, expressing the cell specific marker CD31.
For the investigation of MM progression in vitro, a 3D melanoma skin equivalent was established. Melanoma cells were incorporated in the epidermal part of FTSEs, representing the native microenvironment of the tumor. Melanoma nests grew at the dermo-epidermal junction within the well stratified epidermis and were characterized by the expression of common melanoma markers. First experiments were conducted showing the feasibility of combining the melanoma model with the vFTSE, resulting in skin models with tumors at the dermo-epidermal junction and lumen-like structures in the dermis.
Taken together, the models presented in this thesis provide further steps towards the establishment of a vascularized, perfusable melanoma model to study melanoma progression and metastasis.
Background: Granulomatosis with polyangiitis, also known as Wegener’s granulomatosis, is a chronic systemic inflammatory disease that can also involve the eyes. We report a case of massive retinal and preretinal hemorrhages with perivascular changes as the initial signs in granulomatosis with polyangiitis (Wegener’s granulomatosis).
Case presentation: A 39-year-old Caucasian male presented with blurred vision in his right eye, myalgia and arthralgia, recurrent nose bleeds and anosmia. Fundus image of his right eye showed massive retinal hemorrhages and vasculitis-like angiopathy, although no fluorescein extravasation was present in fluorescein angiography. Laboratory investigations revealed an inflammation with increased C-reactive protein, elevated erythrocyte sedimentation rate and neutrophil count. Tests for antineutrophil cytoplasmic antibodies (ANCA) were positive for c-ANCA (cytoplasmatic ANCA) and PR3-ANCA (proteinase 3-ANCA). Renal biopsy demonstrated a focal segmental necrotizing glomerulonephritis. Granulomatosis with polyangiitis (Wegener’s granulomatosis) was diagnosed and a combined systemic therapy of cyclophosphamide and corticosteroids was initiated. During 3 months of follow-up, complete resorption of retinal hemorrhages was seen and general complaints as well as visual acuity improved during therapy.
Conclusion: Vasculitis-like retinal changes can occur in Wegener’s granulomatosis. Despite massive retinal and preretinal hemorrhages that cause visual impairment, immunosuppressive therapy can improve ocular symptoms.
Now that mechanical thrombectomy has substantially improved outcomes after large-vessel occlusion stroke in up to every second patient, futile reperfusion wherein successful recanalization is not followed by a favorable outcome is moving into focus. Unfortunately, blood-based biomarkers, which identify critical stages of hemodynamically compromised yet reperfused tissue, are lacking. We recently reported that hypoxia induces the expression of endoglin, a TGF-β co-receptor, in human brain endothelium in vitro. Subsequent reoxygenation resulted in shedding. Our cell model suggests that soluble endoglin compromises the brain endothelial barrier function. To evaluate soluble endoglin as a potential biomarker of reperfusion (-injury) we analyzed its concentration in 148 blood samples of patients with acute stroke due to large-vessel occlusion. In line with our in vitro data, systemic soluble endoglin concentrations were significantly higher in patients with successful recanalization, whereas hypoxia alone did not induce local endoglin shedding, as analyzed by intra-arterial samples from hypoxic vasculature. In patients with reperfusion, higher concentrations of soluble endoglin additionally indicated larger infarct volumes at admission. In summary, we give translational evidence that the sequence of hypoxia and subsequent reoxygenation triggers the release of vasoactive soluble endoglin in large-vessel occlusion stroke and can serve as a biomarker for severe ischemia with ensuing recanalization/reperfusion.
Transmission of Trypanosoma brucei by tsetse flies involves the deposition of the cell cycle-arrested metacyclic life cycle stage into mammalian skin at the site of the fly’s bite. We introduce an advanced human skin equivalent and use tsetse flies to naturally infect the skin with trypanosomes. We detail the chronological order of the parasites’ development in the skin by single-cell RNA sequencing and find a rapid activation of metacyclic trypanosomes and differentiation to proliferative parasites. Here we show that after the establishment of a proliferative population, the parasites enter a reversible quiescent state characterized by slow replication and a strongly reduced metabolism. We term these quiescent trypanosomes skin tissue forms, a parasite population that may play an important role in maintaining the infection over long time periods and in asymptomatic infected individuals.
In this work, the laser control of molecules was investigated theoretically. In doing so, emphasis was layed on entering vectorial properties and in particular the orientation in the laboratory frame. Therefore, the rotational degree of freedom had to be included in the quantum mechanical description. The coupled vibrational and rotational dynamics was examined, which is usually not done in coherent control theory. Local control theory was applied, where the field is determined from the dynamics of a system, which reacts with an instantaneous response to the perturbation and, in turn, determines the field again. Thus, the field is entangled with the quantum mechanical motion and the presented examples document, that this leads to an intuitive interpretation of the fields in terms of the underlying molecular dynamics. The limiting case of a classical treatment was shown to give similar results and hence, eases to understand the complicated structure of the control fields. In a different approach, the phase- and amplitude shaping of laser fields was systematically studied in the context of controlling population transfer in molecules.
West Africa is one of the fastest growing regions in the world with annual population growth rates of more than three percent for several countries. Since the 1950s, West Africa experienced a fivefold increase of inhabitants, from 71 to 353 million people in 2015 and it is expected that the region’s population will continue to grow to almost 800 million people by the year 2050. This strong trend has and will have serious consequences for food security since agricultural productivity is still on a comparatively low level in most countries of West Africa. In order to compensate for this low productivity, an expansion of agricultural areas is rapidly progressing. The mapping and monitoring of agricultural areas in West Africa is a difficult task even on the basis of remote sensing. The small scale extensive farming practices with a low level of agricultural inputs and mechanization make the delineation of cultivated land from other land cover and land use (LULC) types highly challenging. In addition, the frequent cloud coverage in the region considerably decreases the availability of earth observation datasets. For the accurate mapping of agricultural area in West Africa, high temporal as well as spatial resolution is necessary to delineate the small-sized fields and to obtain data from periods where different LULC types are distinguishable. However, such consistent time series are currently not available for West Africa. Thus, a spatio-temporal data fusion framework was developed in this thesis for the generation of high spatial and temporal resolution time series.
Data fusion algorithms such as the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) enjoyed increasing popularity during recent years but they have hardly been used for the application on larger scales. In order to make it applicable for this purpose and to increase the input data availability, especially in cloud-prone areas such as West Africa, the ESTARFM framework was developed in this thesis introducing several enhancements. An automatic filling of cloud gaps was included in the framework in order to use even partly cloud-covered Landsat images for the fusion without producing gaps on the output images. In addition, the ESTARFM algorithm was improved to automatically account for regional differences in the heterogeneity of the study region. Further improvements comprise the automation of the time series generation as well as the significant acceleration of the processing speed through parallelization. The performance of the developed ESTARFM framework was tested by fusing an 8-day NDVI time series from Landsat and MODIS data for a focus area of 98,000 km² in the border region between Burkina Faso and Ghana. The results of this test show the capability of the ESTARFM framework to accurately produce high temporal resolution time series while maintaining the spatial detail, even in such a heterogeneous and cloud-prone region.
The successfully tested framework was subsequently applied to generate consistent time series as the basis for the mapping of agricultural area in Burkina Faso for the years 2001, 2007, and 2014. In a first step, high temporal (8-day) and high spatial (30 m) resolution NDVI time series for the entire country and the three years were derived with the ESTARFM framework. More than 500 Landsat scenes and 3000 MODIS scenes were automatically processed for this purpose. From the fused ESTARFM NDVI time series, phenological metrics were extracted and together with the single time steps of NDVI served as input for the delineation of rainfed agricultural areas, irrigated agricultural areas and plantations. The classification was conducted with the random forest algorithm at a 30 m spatial resolution for entire Burkina Faso and the three years 2001, 2007, and 2014. For the training and validation of the classifier, a randomly sampled reference dataset was generated from Google Earth images based on expert knowledge of the region. The overall classification accuracies of 92% (2001), 91% (2007), and 91% (2014) indicate the well-functioning of the developed methodology. The resulting maps show an expansion of agricultural area of 91% from about 61,000 km² in 2001 to 116,900 km² in 2014. While rainfed agricultural areas account for the major part of this increase, irrigated areas and plantations also spread considerably. Especially the expansion of irrigation systems and plantation area can be explained by the promotion through various national and international development projects. The increase of agricultural areas goes in line with the rapid population growth in most of Burkina Faso’s provinces which still had available land resources for an expansion of agricultural area. An analysis of the development of agricultural areas in the vicinity of protected areas highlighted the increased human pressure on these reserves. The protection of the remnant habitats for flora and fauna while at the same time improving food security for a rapidly growing population, are the major challenges for the region in the future.
The developed ESTARFM framework showed great potential beyond its utilization for the mapping of agricultural area. Other large-scale research that requires a sufficiently high temporal and spatial resolution such as the monitoring of land degradation or the investigation of land surface phenology could greatly benefit from the application of this framework.
Freely available satellite data at Google Earth Engine (GEE) cloud platform enables vegetation phenology analysis across different scales very efficiently. We evaluated seasonal and annual phenology of the old-growth Hyrcanian forests (HF) of northern Iran covering an area of ca. 1.9 million ha, and also focused on 15 UNESCO World Heritage Sites. We extracted bi-weekly MODIS-NDVI between 2017 and 2020 in GEE, which was used to identify the range of NDVI between two temporal stages. Then, changes in phenology and growth were analyzed by Sentinel 2-derived Temporal Normalized Phenology Index. We modelled between seasonal phenology and growth by additionally considering elevation, surface temperature, and monthly precipitation. Results indicated considerable difference in onset of forests along the longitudinal gradient of the HF. Faster growth was observed in low- and uplands of the western zone, whereas it was lower in both the mid-elevations and the western outskirts. Longitudinal range was a major driver of vegetation growth, to which environmental factors also differently but significantly contributed (p < 0.0001) along the west-east gradient. Our study developed at GEE provides a benchmark to examine the effects of environmental parameters on the vegetation growth of HF, which cover mountainous areas with partly no or limited accessibility.
Lightning has fascinated humanity since the beginning of our existence. Different types of lightning like sprites and blue jets were discovered, and many more are theorized. However, it is very likely that these phenomena are not exclusive to our home planet. Venus’s dense and active atmosphere is a place where lightning is to be expected. Missions like Venera, Pioneer, and Galileo have carried instruments to measure electromagnetic activity. These measurements have indeed delivered results. However, these results are not clear. They could be explained by other effects like cosmic rays, plasma noise, or spacecraft noise. Furthermore, these lightning seem different from those we know from our home planet. In order to tackle these issues, a different approach to measurement is proposed. When multiple devices in different spacecraft or locations can measure the same atmospheric discharge, most other explanations become increasingly less likely. Thus, the suggested instrument and method of VELEX incorporates multiple spacecraft. With this approach, the question about the existence of lightning on Venus could be settled.
The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer’s dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN. Ventralizing factors [i.e., purmorphamine and Sonic hedgehog (SHH)] were applied at different time points, time intervals, and concentrations. In addition, caudal identity was prevented by the use of a small molecule XAV-939 that inhibits the Wnt-pathway. After patterning, gene expression profiles were analyzed by quantitative PCR (qPCR). Rostro-ventral patterning is most effective when initiated simultaneously with neural induction. The most promising combination of patterning factors was 0.5 μM of purmorphamine and 1 μM of XAV-939, which induces the highest expression of transcription factors specific for the medial ganglionic eminence, the source of GABAergic inter- and cholinergic neurons in the telencephalon. Upon maturation of cells, the immune phenotype, as well as electrophysiological properties were investigated showing the presence of marker proteins specific for BFCN (choline acetyltransferase, ISL1, p75, and NKX2.1) and GABAergic neurons. Moreover, a considerable fraction of measured cells displayed mature electrophysiological properties. Synaptic boutons containing the vesicular acetylcholine transporter (VACHT) could be observed in the vicinity of the cells. This work will help to generate basal forebrain interneurons from hiPSCs, providing a promising platform for modeling neurological diseases, such as Alzheimer’s disease or Dystonia.
We aimed to determine a detailed regional ventricular distribution pattern of the novel cardiac nerve PET radiotracer \(^{18}\)F-LMI1195 in healthy rabbits. Ex-vivo high resolution autoradiographic imaging was conducted to identify accurate ventricular distribution of \(^{18}\)F-LMI1195. In healthy rabbits, \(^{18}\)F-LMI1195 was administered followed by the reference perfusion marker \(^{201}\)Tl for a dual-radiotracer analysis. After 20 min of \(^{18}\)F-LMI1195 distribution time, the rabbits were euthanized, the hearts were extracted, frozen, and cut into 20-μm short axis slices. Subsequently, the short axis sections were exposed to a phosphor imaging plate to determine \(^{18}\)F-LMI1195 distribution (exposure for 3 h). After complete \(^{18}\)F decay, sections were re-exposed to determine 201Tl distribution (exposure for 7 days). For quantitative analysis, segmental regions of Interest (ROIs) were divided into four left ventricular (LV) and a right ventricular (RV) segment on mid-ventricular short axis sections. Subendocardial, mid-portion, and subepicardial ROIs were placed on the LV lateral wall. \(^{18}\)F-LMI1195 distribution was almost homogeneous throughout the LV wall without any significant differences in all four LV ROIs (anterior, posterior, septal and lateral wall, 99 ± 2, 94 ± 5, 94 ± 4 and 97 ± 3%LV, respectively, n.s.). Subepicardial \(^{201}\)Tl uptake was significantly lower compared to the subendocardial portion (subendocardial, mid-portion, and subepicardial activity: 90 ± 3, 96 ± 2 and *80 ± 5%LV, respectively, *p < 0.01 vs. mid-portion). This was in contradistinction to the transmural wall profile of \(^{18}\)F-LMI1195 (90 ± 4, 96 ± 5 and 84 ± 4%LV, n.s.). A slight but significant discrepant transmural radiotracer distribution pattern of \(^{201}\)Tl in comparison to \(^{18}\)F-LMI1195 may be a reflection of physiological sympathetic innervation and perfusion in rabbit hearts.
Although the concept of botanical carnivory has been known since Darwin's time, the molecular mechanisms that allow animal feeding remain unknown, primarily due to a complete lack of genomic information. Here, we show that the transcriptomic landscape of the Dionaea trap is dramatically shifted toward signal transduction and nutrient transport upon insect feeding, with touch hormone signaling and protein secretion prevailing. At the same time, a massive induction of general defense responses is accompanied by the repression of cell death-related genes/processes. We hypothesize that the carnivory syndrome of Dionaea evolved by exaptation of ancient defense pathways, replacing cell death with nutrient acquisition.
The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na\(^+\)- and K\(^+\)-permeable mutants function as ion channels rather than K\(^+\) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na\(^+\)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.
Venus Research Station
(2023)
Because of the extreme conditions in the atmosphere, Venus has been less explored than for example Mars. Only a few probes have been able to survive on the surface for very short periods in the past and have sent data. The atmosphere is also far from being fully explored. It could even be that building blocks of life can be found in more moderate layers of the planet’s atmosphere. It can therefore be assumed that the planet Venus will increasingly become a focus of exploration. One way to collect significantly more data in situ is to build and operate an atmospheric research station over an extended period of time. This could carry out measurements at different positions and at different times and thus significantly expand our knowledge of the planet. In this work, the design of a Venus Research Station floating within the Venusian atmosphere is presented, which is complemented by the design of deployable atmospheric Scouts. The design of these components is done on a conceptual basis.
The known YAP inhibitor verteporfin is capable of repressing IL‐17A production in Th17 cells. However, this effect is mediated independently of YAP and can ameliorate Th17‐mediated experimental autoimmune encephalomyelitis (EAE) upon in vivo administration. The data suggest verteprofin's mode of action for the design of novel therapeutic autoimmune disease intervention.
Bacteriosponges contain large amounts of morphologically and phylogenetically diverse microorganisms in their mesohyl. The association is permanent, stable and highly specific, however, little is known about the establishment and maintenance of this association. The first aim of this Ph.D. thesis was to examine cospeciation between eight Aplysina species from the Mediterranean and Caribbean and their cyanobacterial associates. Host phylogeny was constructed with 18S rDNA and ITS-2 sequences using an alignment based on the secondary structure of the molecular markers and five different algorithms each. The genus Aplysina appeared as monophyletic. Aplysina sponges could be distinguished into a Caribbean and a Mediterranean cluster and a possible Tethyan origin is suggested. Comparison of the host phylogeny to the 16S rDNA phylogeny of the cyanobacterial strains revealed the lack of a congruent pattern. Therefore it is proposed that Aplysina sponges have not cospeciated with their cyanobacterial phylotypes and probably also not with other sponge specific microbes. The second aim of this Ph.D. thesis was to examine vertical transmission of microorganisms through reproductive stages of sponges. A general transmission electron microscopy (TEM) suvey revealed a clear correlation in that bacteriosponges always contained many microorganisms in their reproductive stages whereas non-bacteriosponges were always devoid of microbes in their reproductive stages. The transmission of the microbial community via sponge reproductive stages is concluded. Based on the previous results Ircinia felix was chosen for a detailed documentation of vertical transmission. I. felix larvae contained large amounts of microorganisms extracellularly in the central region whereas the outer region was almost free of microbes as shown by TEM. In I. felix juveniles microorganisms were located between densely packed sponge cells. The microbial profiles of I. felix adult, larvae, and juveniles were compared using denaturing gradient gel electrophoresis (DGGE). Similar microbial community patterns were found in adult and the respective larvae indicating that a large subset of the adult microbial community was vertically transmitted. In contrast, microbial communities of larvae pools released by different adult individuals seemed to be more variable. Juvenile banding patterns were a mixture of sponge specific and seawater microbes due to DNA extraction artefacts but demonstrated that at least half of the adult microbial community is present in the next generation. Finally, a comprehensive phylogenetic analysis was conducted by sequencing excised DGGE bands from adult and offspring of the bacteriosponges Agelas wiedenmayeri, I. felix, and Smenospongia aurea and by taking additional 16S rDNA sequences of Ectyoplasia ferox and Xestospongia muta (unpublished data of the laboratory). The identification of 24 vertical transmission clusters in at least 8 eubacterial phyla demonstrates that a complex and uniform microbial community is transferred via sponge reproductive stages. Vertical transmission is specific in that the microorganisms of bacteriosponges, but not those from seawater, are passed on, but unselective in that there appears to be no differentiation between individual sponge-specific lineages. In conclusion, vertical transmission points to a mutualistic and long-term association of bacteriosponges and complex microbial consortia.
Improved radiological examinations with newly developed 3D models may increase understanding of Meniere's disease (MD). The morphology and course of the vestibular aqueduct (VA) in the temporal bone might be related to the severity of MD. The presented study explored, if the VA of MD and non-MD patients can be grouped relative to its angle to the semicircular canals (SCC) and length using a 3D model. Scans of temporal bone specimens (TBS) were performed using micro-CT and micro flat panel volume computed tomography (mfpVCT). Furthermore, scans were carried out in patients and TBS by computed tomography (CT). The angle between the VA and the three SCC, as well as the length of the VA were measured. From these data, a 3D model was constructed to develop the vestibular aqueduct score (VAS). Using different imaging modalities it was demonstrated that angle measurements of the VA are reliable and can be effectively used for detailed diagnostic investigation. To test the clinical relevance, the VAS was applied on MD and on non-MD patients. Length and angle values from MD patients differed from non-MD patients. In MD patients, significantly higher numbers of VAs could be assigned to a distinct group of the VAS. In addition, it was tested, whether the outcome of a treatment option for MD can be correlated to the VAS.
Vevacious: a tool for finding the global minima of one-loop effective potentials with many scalars
(2013)
Several extensions of the Standard Model of particle physics contain additional scalars implying a more complex scalar potential compared to that of the Standard Model. In general these potentials allow for charge- and/or color-breaking minima besides the desired one with correctly broken SU(2) L ×U(1) Y . Even if one assumes that a metastable local minimum is realized, one has to ensure that its lifetime exceeds that of our universe. We introduce a new program called Vevacious which takes a generic expression for a one-loop effective potential energy function and finds all the tree-level extrema, which are then used as the starting points for gradient-based minimization of the one-loop effective potential. The tunneling time from a given input vacuum to the deepest minimum, if different from the input vacuum, can be calculated. The parameter points are given as files in the SLHA format (though is not restricted to supersymmetric models), and new model files can be easily generated automatically by the Mathematica package SARAH. This code uses HOM4PS2 to find all the minima of the tree-level potential, PyMinuit to follow gradients to the minima of the one-loop potential, and CosmoTransitions to calculate tunneling times.
The thesis contains two major parts. The first part deals with structural investigations on different coordination compounds performed by using infrared absorption and FT-Raman spectroscopy in combination with density functional theory calculations. In the first section of this part the starting materials Ph2P-N(H)SiMe3 and Ph3P=NSiMe3 and their corresponding [(MeSi)2NZnPh2P-NSiMe3]2 and Li(o-C6H4PPh2NSiMe3)]2·Et2O complexes have been investigated in order to determine the influence of the metal coordination on the P–N bond length. In the next section the vibrational spectra of four hexacoordinated silicon(IV) and germanium(IV) complexes with three symmetrical bidentate oxalato(2-) ligands have been elucidated. Kinetic investigations of the hydrolysis of two of them, one with silicon and another one with germanium, have been carried out at room temperature and at different pH values and it was observed that the hydrolysis reaction occurs only for the silicon compound, the fastest reaction taking place at acidic pH. In the last section of this part, the geometric configurations of some hexacoordinated silicon(IV) complexes with three unsymmetrical bidentate hydroximato(2-) ligands have been determined. The second part of the thesis contains vibrational investigations of some biologically active molecules performed by means of Raman spectroscopy together with theoretical simulations. The SER spectra of these molecules at different pH values have also been analysed and the adsorption behaviour on the metal surface as well as the influence of the pH on the molecule-substrate interaction have been established.
Infrared (IR) and Raman spectroscopy are among the most widely used techniques in the physical and natural sciences today. Vibrational spectroscopy, including IR and Raman spectroscopy, has both a long and interesting history and an illustrious record of contributions to science. Spectroscopy in the pharmaceutical industry is dominated by techniques such as nuclear magnetic resonance (NMR) and mass spectrometry (MS) for the elucidation of chemical structures. Despite this, the versatility of infrared spectroscopy ensures it still remains a key technique in quality control laboratories, and in applications where solid form characterization or minimal sample preparation is a necessity. Raman spectroscopy has many uses in the pharmaceutical and chemical industry, but its strengths is in solid form analysis. It is regularly used to identify compounds, and results are used in the release of pharmaceutical and chemical products. This work consists of 8 chapters, which cover the vibrational spectroscopy beginning with the theory and instrumentation, continuing with the experimental setup and probes description, and completing with results and discussions of the experiments. The first chapter of this work introduces Raman spectroscopy as a dominant technique used in pharmaceutical and chemical industry. The theoretical background regarding vibrational spectroscopy (IR and Raman) is accounted for in the second chapter of this work, while the samples presentation, the experimental procedures, and the description of the apparatus together with the computational details are briefly specified in the third chapter. The fourth chapter investigates the concentration dependent wavenumber shifts and linewidth changes of tetrahydrofuran in a binary system. Many of the applications in food science rely heavily on Raman spectroscopy, often preceding the biomedical applications. The characterization and identification of food additives using Raman, surface-enhanced Raman spectroscopy, and theoretical calculations is in detail depicted in the fifth chapter, whereas in the sixth and seventh chapters the monitoring of several medicines and various lanthanide complexes with anticancer properties, respectively, employing IR and Raman techniques are treated. These last two chapters address applications of vibrational spectroscopy to pharmaceutical products, and include the use of vibrational spectroscopy in combinatorial chemistry and density functional theory, a modality increasingly used by the pharmaceutical industry for the discovery if new pharmacologically active substances.
In the current work, several well-known pharmaceuticals (1,4-dihydrazinophthalazine sulfate, caffeine, and papaverine hydrochloride) and new organometallic compounds (nickel(II) cupferronato complexes NiL2An, L = PhN2O2-, n = 1, A = o-phenanthroline (1), o,o’-bipyridine (2) and n = 2, A = H2O (3), o-NH2Py (4), o-C6H4(NH2)2 (5); silylene-bridged dinuclear iron complexes [Cp(OC)2Fe]2SiX2 (X = H (6), F (7), Cl (8), Br (9), I (10)); 3-silaoxetane 3,3-dimethyl-2,2,4,4-tetraphenyl-1-oxa-3-silacyclobutane (11) and 3-silathietane 3,3-dimethyl-2,2,4,4-tetraphenyl-1-sila-3-thiacyclobutane (12) compounds), which have successfully been characterized by using vibrational spectroscopy in conjunction with accurate density functional theory (DFT) calculations, are presented. The DFT computed molecular geometries of the species of interest reproduced the crystal structure data very well and in conjunction with IR and Raman measurements helped us to clarify the structures of the compounds, for which no experimental data were available; and this, especially for the new organometallic compounds, where the X-Ray analysis was limited by the non-availability of single crystals (3, 5, 10). Furthermore, a natural population analysis (NPA) and natural bond orbital (NBO) calculations together with a detailed analysis of the IR and Raman experimental as well as calculated spectra of the new organometallic compounds, allowed us to study some special bonding situations (1-12) or to monitor the structural changes observed with the change in temperature during the Raman experiments (11, 12). By combining these two methods (DFT and vibrational spectroscopy), the auspicious results obtained on the organometallic compounds 6-12 and overall in literature, made us confident of the power of theoretical calculations in aiding the interpretation of rich SERS spectra by solving some interesting issues. Consequently, the Raman and SERS spectra of well-known pharmaceuticals (1,4-dihydrazinophthalazine sulfate, caffeine, and papaverine hydrochloride) or new potentially biological active organometallic complexes (1-5), that were synthetized by our coworkers, were discussed with the assistance of the accurate results obtained from DFT calculations (structural parameters, harmonic vibrational wavenumbers, Raman scattering activities), and many previous incomplete assignments have been analyzed and improved. This allowed us to establish the vibrational behavior of these biological compounds near a biological artificial model at different pH values or concentrations (Ag substrate), taking into account that information about the species present under particular conditions could be of great importance for the interpretation of biochemical processes. The total electron density of molecules and the partial charges situated on selected atoms, which were determined theoretically by NPA, allowed us to establish the probability of different atoms acting as an adsorptive site for the metal surface. Moreover, a closer examination of the calculated orbitals of molecules brought further arguments on the presence or absence of the photoproducts at the Ag surface during the irradiation (1,4-dihydrazinophthalazine sulfate). Overall, the results provide a benchmark illustration of the virtues of DFT in aiding the interpretation of rich vibrational spectra attainable for larger polyatomic adsorbates by using SERS, as well as in furnishing detailed insight into the relation between the vibrational properties and the nature of the Ag substrate-adsorbate bonding. Therefore, we strongly believe that theoretical calculations will become a matter of rapidly growing scientific and practical interest in SERS.
In the frame of this thesis vibronic and electronic states of organic molecules have been examined. A central question is the interaction within and between the molecules in thin films and at metal-organic interfaces. The main experimental tools were high resolution electron energy loss spectroscopy (HREELS) and high resolution near edge X-ray absortion fine structure (NEXFAS). The electronic and vibronic structure of thin NTCDA films was examined with low energy electrons as probe, i.e. HREELS. The spectra of the electronic excited molecular orbitals of submonolayer NTCDA on a Ag(111) shows a partially filled orbital. The interaction between this orbital and the total symetric molecular vibrations leads to the typical Fano peak profiles which are seen in the vibrational spectra. The sub-monolayer superstructure can be driven to a phase transition into an disordered phase upon cooling, which is also seen in the electronic and vibronic excitation spectra. Multilayers show flat lying or upright standing molecules as a function of the preparation conditions. The upright standing molecules show an island growth mode, where the islands are well ordered and exhibit a structure in diffraction experiments which can be attributed to the molecular crystal structure. In order to examine the order in more detail various thin films were examined using SPALEED as function of film thickness and preparation parameters. In case of a low temperature substrate no long range order leading to a diffraction pattern was found. In contrast growth on room temperature substrates leads to island growth of films in a structure of the molecular crystal, where two preferred orientations of the islands relative to the substrate were found. In case of thick films the reference to the substrate gets lost and the molecular crystals grow with a defined crystal direction with respect to the surface but with an arbitrary azimuthal orientation leading to circles in the diffraction pattern. NTCDA monolayers on a Ag(111) surface using HREELS as a tool were examined. The electronic excitation spectra reveal a partially filled molecular orbital which is strongly shifted compared to the multilayer. The existence of this state is responsible for the activation of normally forbidden Ag modes in the vibrational spectra. Due to the electron phonon coupling these modes exhibit a Fano like peak shape. Cooling a monolayer leads to a phase transition with strong changes in the spectroscopic features both in electronic and vibronic excitations. In case of the molecule ANQ the intramolecular interaction was examined. In the oxygen NEXAFS spectra a vibronic fine structure is found, which leads to the conclusion that asymmetric potentials are involved. It is an interesting question if the fundamental vibration is has C-H or C=O character. In order to address this question spectra of condensed and gas phase ANQ were compared to an ANQ derivate (ANQ- Br$_2$Cl$_2$), with the conclusion that the coupling is most likely to a C=O mode. High resolution C1s spectra of hydrogenated and fully deuterated naphthalene both in gas and condensed phase have been presented. Depending on the final state orbital distinct differences have been found between gas and condensed phase. A energetic shift of resonances (Res. B, C, D) is interpreted as effect of $\pi$-$\pi$ interaction in the condensed phase. This is especially notable for resonance B which is undoubtly assigned to an excitation into a $\pi^*$ orbital. The results lead to an interpretation, that for organic molecular crystals more than pure van-derWaals interaction has to be taken into account. In summary it is found that the intramolecular interaction in NEXAFS spectra is preferentially coupled to one or a few vibronic progressions. Due to the delocalized electronic system maybe even states which are not spatially near the core excited atom can be involved. It could be shown that a condensation of the molecules in thin films leads to changes within the spectra. The influence the intermolecular interaction can be clearly seen in this finding, where additional hints are found that more than mere van-der-Waals binding has to be taken into account.
To fire action-potential-like electrical signals, the vacuole membrane requires the two-pore channel TPC1, formerly called SV channel. The TPC1/SV channel functions as a depolarization-stimulated, non-selective cation channel that is inhibited by luminal Ca\(^{2+}\). In our search for species-dependent functional TPC1 channel variants with different luminal Ca\(^{2+}\) sensitivity, we found in total three acidic residues present in Ca\(^{2+}\) sensor sites 2 and 3 of the Ca\(^{2+}\)-sensitive AtTPC1 channel from Arabidopsis thaliana that were neutral in its Vicia faba ortholog and also in those of many other Fabaceae. When expressed in the Arabidopsis AtTPC1-loss-of-function background, wild-type VfTPC1 was hypersensitive to vacuole depolarization and only weakly sensitive to blocking luminal Ca\(^{2+}\). When AtTPC1 was mutated for these VfTPC1-homologous polymorphic residues, two neutral substitutions in Ca\(^{2+}\) sensor site 3 alone were already sufficient for the Arabidopsis At-VfTPC1 channel mutant to gain VfTPC1-like voltage and luminal Ca\(^{2+}\) sensitivity that together rendered vacuoles hyperexcitable. Thus, natural TPC1 channel variants exist in plant families which may fine-tune vacuole excitability and adapt it to environmental settings of the particular ecological niche.
In this work, a toolbox was provided to create three-component polymer conjugates with a defined architecture, designed to bear different biocomponents that can interact with larger biological systems in biomacromolecular recognition experiments. The target architecture is the attachment of two biomolecule ‘arms’ to the alpha telechelic end point of a polymer and fixating the conjugate to the gold surface of SAW and SPR sensor chips with the polymer’s other omega chain end. This specific design of a conjugate will be implemented by using a strategy to yield novel double alpha as well as omega telechelic functionalized POx and the success of all cascade reaction steps leading to the final conjugation product will be proven through affinity measurements between covalently bound mannose and ConA. All reactions were performed on a low molecular model level first and then transferred to telechelic and also side chain functionalized polymer systems.
Motor aspects of Parkinson’s disease, such as fluctuations and dyskinesia, can be reliably evaluated using a variety of “wearable” technologies, but practical guidance on objective measurement (OM) and the optimum use of these devices is lacking. Therefore, as a first step, a panel of movement disorder specialists met to provide guidance on how OM could be assessed and incorporated into clinical guidelines. A key aspect of the incorporation of OM into the management of Parkinson’s disease (PD) is defining cutoff values that separate “controlled” from “uncontrolled” symptoms that can be modified by therapy and that relate to an outcome that is relevant to the person with PD (such as quality of life). Defining cutoffs by consensus, which can be subsequently tested and refined, is the first step to optimizing OM in the management of PD. OM should be used by all clinicians that treat people with PD but the least experienced may find the most value, but this requires guidance from experts to allow non-experts to apply guidelines. While evidence is gained for devices that produce OM, expert opinion is needed to supplement the evidence base.
Background: In principle, the elimination of malignancies by oncolytic virotherapy could proceed by different mechanisms - e.g. tumor cell specific oncolysis, destruction of the tumor vasculature or an anti-tumoral immunological response. In this study, we analyzed the contribution of these factors to elucidate the responsible mechanism for regression of human breast tumor xenografts upon colonization with an attenuated vaccinia virus (VACV). Methods: Breast tumor xenografts were analyzed 6 weeks post VACV infection (p.i.; regression phase) by immunohistochemistry and mouse-specific expression arrays. Viral-mediated oncolysis was determined by tumor growth analysis combined with microscopic studies of intratumoral virus distribution. The tumor vasculature was morphologically characterized by diameter and density measurements and vessel functionality was analyzed by lectin perfusion and extravasation studies. Immunological aspects of viral-mediated tumor regression were studied in either immune-deficient mouse strains (T-, B-, NK-cell-deficient) or upon cyclophosphamide-induced immunosuppression (MHCII+-cell depletion) in nude mice. Results: Late stage VACV-infected breast tumors showed extensive necrosis, which was highly specific to cancer cells. The tumor vasculature in infected tumor areas remained functional and the endothelial cells were not infected. However, viral colonization triggers hyperpermeability and dilatation of the tumor vessels, which resembled the activated endothelium in wounded tissue. Moreover, we demonstrated an increased expression of genes involved in leukocyte-endothelial cell interaction in VACV-infected tumors, which orchestrate perivascular inflammatory cell infiltration. The immunohistochemical analysis of infected tumors displayed intense infiltration of MHCII-positive cells and colocalization of tumor vessels with MHCII+/CD31+ vascular leukocytes. However, GI-101A tumor growth analysis upon VACV-infection in either immunosuppressed nude mice (MHCII+-cell depleted) or in immune-deficient mouse strains (T-, B-, NK-cell-deficient) revealed that neither MHCII-positive immune cells nor T-, B-, or NK cells contributed significantly to VACV-mediated tumor regression. In contrast, tumors of immunosuppressed mice showed enhanced viral spreading and tumor necrosis. Conclusions: Taken together, these results indicate that VACV-mediated oncolysis is the primary mechanism of tumor shrinkage in the late regression phase. Neither the destruction of the tumor vasculature nor the massive VACV-mediated intratumoral inflammation was a prerequisite for tumor regression. We propose that approaches to enhance viral replication and spread within the tumor microenvironment should improve therapeutical outcome.
Virotherapy using oncolytic vaccinia virus (VACV) strains is one promising new strategy for cancer therapy. We have previously reported that oncolytic vaccinia virus strains expressing an anti-VEGF (Vascular Endothelial Growth Factor) single-chain antibody (scAb) GLAF-1 exhibited significant therapeutic efficacy for treatment of human tumor xenografts. Here, we describe the use of oncolytic vaccinia virus GLV-1h109 encoding GLAF-1 for canine cancer therapy. In this study we analyzed the virus-mediated delivery and production of scAb GLAF-1 and the oncolytic and immunological effects of the GLV-1h109 vaccinia virus strain against canine soft tissue sarcoma and canine prostate carcinoma in xenograft models. Cell culture data demonstrated that the GLV-1h109 virus efficiently infect, replicate in and destroy both tested canine cancer cell lines. In addition, successful expression of GLAF-1 was demonstrated in virus-infected canine cancer cells and the antibody specifically recognized canine VEGF. In two different xenograft models, the systemic administration of the GLV-1h109 virus was found to be safe and led to anti-tumor and immunological effects resulting in the significant reduction of tumor growth in comparison to untreated control mice. Furthermore, tumor-specific virus infection led to a continued production of functional scAb GLAF-1, resulting in inhibition of angiogenesis. Overall, the GLV-1h109-mediated cancer therapy and production of immunotherapeutic anti-VEGF scAb may open the way for combination therapy concept i.e. vaccinia virus mediated oncolysis and intratumoral production of therapeutic drugs in canine cancer patients.
Pain-associated approach and avoidance behaviours are critically involved in the development and maintenance of chronic pain. Empirical research suggests a key role of operant learning mechanisms, and first experimental paradigms were developed for their investigation within a controlled laboratory setting. We introduce a new Virtual Reality paradigm to the study of pain-related behaviour and investigate pain experiences on multiple dimensions. The paradigm evaluates the effects of three-tiered heat-pain stimuli applied contingent versus non-contingent with three types of arm movements in naturalistic virtual sceneries. Behaviour, self-reported pain-related fear, pain expectancy and electrodermal activity were assessed in 42 healthy participants during an acquisition phase (contingent movement-pain association) and a modification phase (no contingent movement-pain association). Pain-associated approach behaviour, as measured by arm movements followed by a severe heat stimulus, quickly decreased in-line with the arm movement-pain contingency. Slower effects were observed in fear of movement-related pain and pain expectancy ratings. During the subsequent modification phase, the removal of the pain contingencies modified all three indices. In both phases, skin conductance responses resemble the pattern observed for approach behaviour, while skin conductance levels equal the pattern observed for the self-ratings. Our findings highlight a fast reduction in approach behaviour in the face of acute pain and inform about accompanying psychological and physiological processes. We discuss strength and limitations of our paradigm for future investigations with the ultimate goal of gaining a comprehensive understanding of the mechanisms involved in chronic pain development, maintenance, and its therapy.
Virtual online training has emerged as one of the top 20 worldwide fitness trends for 2021 and continues to develop rapidly. Although this allows the cycling community to engage in virtual training and competition, critical evaluation of virtual training platforms is limited. Here, we discuss the strengths, weaknesses, opportunities and threats associated with virtual training technology and cycling in an attempt to enhance awareness of such aspects. Strengths include immersive worlds, innovative drafting mechanics, and versatility. Weaknesses include questionable data accuracy, inadequate strength and reliability of power-speed algorithms. Opportunities exist for expanding strategic partnerships with major cycling races, brands, and sponsors and improving user experience with the addition of video capture and “e-coaching.” Threats are present in the form of cheating during competition, and a lack of uptake and acceptance by a broader community.
Gazes are of central relevance for people. They are crucial for navigating the world and communicating with others. Nevertheless, research in recent years shows that many findings from experimental research on gaze behavior cannot be transferred from the laboratory to everyday behavior. For example, the frequency with which conspecifics are looked at is considerably higher in experimental contexts than what can be observed in daily behavior. In short: findings from laboratories cannot be generalized into general statements. This thesis is dedicated to this matter. The dissertation describes and documents the current state of research on social attention through a literature review, including a meta-analysis on the /gaze cueing/ paradigm and an empirical study on the robustness of gaze following behavior. In addition, virtual reality was used in one of the first studies in this research field. Virtual reality has the potential to significantly improve the transferability of experimental laboratory studies to everyday behavior. This is because the technology enables a high degree of experimental control in naturalistic research designs. As such, it has the potential to transform empirical research in the same way that the introduction of computers to psychological research did some 50 years ago. The general literature review on social attention is extended to the classic /gaze cueing/ paradigm through a systematic review of publications and a meta-analytic evaluation (Study 1). The cumulative evidence supported the findings of primary studies: Covert spatial attention is directed by faces. However, the experimental factors included do not explain the surprisingly large variance in the published results. Thus, there seem to be further, not well-understood variables influencing these social processes. Moreover, classic /gaze cueing/ studies have limited ecological validity. This is discussed as a central reason for the lack of generalisability. Ecological validity describes the correspondence between experimental factors and realistic situations. A stimulus or an experimental design can have high and low ecological validity on different dimensions and have different influences on behavior. Empirical research on gaze following behavior showed that the /gaze cueing/ effect also occurs with contextually embedded stimuli (Study 2). The contextual integration of the directional cue contrasted classical /gaze cueing/ studies, which usually show heads in isolation. The research results can thus be transferred /within/ laboratory studies to higher ecologically valid research paradigms. However, research shows that the lack of ecological validity in experimental designs significantly limits the transferability of experimental findings to complex situations /outside/ the laboratory. This seems to be particularly the case when social interactions and norms are investigated. However, ecological validity is also often limited in these studies for other factors, such as contextual embedding /of participants/, free exploration behavior (and, thus, attentional control), or multimodality. In a first study, such high ecological validity was achieved for these factors with virtual reality, which could not be achieved in the laboratory so far (Study 3). Notably, the observed fixation patterns showed differences even under /most similar/ conditions in the laboratory and natural environments. Interestingly, these were similar to findings also derived from comparisons of eye movement in the laboratory and field investigations. These findings, which previously came from hardly comparable groups, were thus confirmed by the present Study 3 (which did not have this limitation). Overall, /virtual reality/ is a new technical approach to contemporary social attention research that pushes the boundaries of previous experimental research. The traditional trade-off between ecological validity and experimental control thus becomes obsolete, and laboratory studies can closely inherit an excellent approximation of reality. Finally, the present work describes and discusses the possibilities of this technology and its practical implementation. Within this context, the extent to which this development can still guarantee a constructive classification of different laboratory tests in the future is examined.
A total of 16 Escherichia coli 06 strains isolated from cases of extraintestinal infections were analysed for the genetic presence and phenotypic expression of fimbrial adhesins ( P, S/FIC, type I), aerobactin and hemolysin. ln addition restriction fragment length polymorphisms (RFLPs) of Xbal-cleaved genomic DNA of seven selected strains, separated by orthogonal field alternation gel electrophoresis {OFAGE) were determined and virulence-associated DNA probes were used for Southern hybridization studies of the Xbal-cleaved genomic DNAs. The virulence characteristics and hybridization patterns obtained differed between the various isolates. ln three isolates hemolysin genes and P fimbrial determinants were located on the same Xbal fragments. Furthermore, multiple copies of FIC determinants (foc) could be detected in two strains. Our data show that the new technique of pulse field electrophoresis tagether with Southern hybridization represents a powerful tool for the genetic analysis of pathogenic bacteria.
Background
Neisseria meningitidis is a naturally transformable, facultative pathogen colonizing the human nasopharynx. Here, we analyze on a genome-wide level the impact of recombination on gene-complement diversity and virulence evolution in N. meningitidis. We combined comparative genome hybridization using microarrays (mCGH) and multilocus sequence typing (MLST) of 29 meningococcal isolates with computational comparison of a subset of seven meningococcal genome sequences.
Principal Findings
We found that lateral gene transfer of minimal mobile elements as well as prophages are major forces shaping meningococcal population structure. Extensive gene content comparison revealed novel associations of virulence with genetic elements besides the recently discovered meningococcal disease associated (MDA) island. In particular, we identified an association of virulence with a recently described canonical genomic island termed IHT-E and a differential distribution of genes encoding RTX toxin- and two-partner secretion systems among hyperinvasive and non-hyperinvasive lineages. By computationally screening also the core genome for signs of recombination, we provided evidence that about 40% of the meningococcal core genes are affected by recombination primarily within metabolic genes as well as genes involved in DNA replication and repair. By comparison with the results of previous mCGH studies, our data indicated that genetic structuring as revealed by mCGH is stable over time and highly similar for isolates from different geographic origins.
Conclusions
Recombination comprising lateral transfer of entire genes as well as homologous intragenic recombination has a profound impact on meningococcal population structure and genome composition. Our data support the hypothesis that meningococcal virulence is polygenic in nature and that differences in metabolism might contribute to virulence.
Strains of the food-borne pathogen Listeria (L.) monocytogenes have diverse virulence potential. This study focused on the virulence of three outbreak strains: the CC1 strain PF49 (serovar 4b) from a cheese-associated outbreak in Switzerland, the clinical CC2 strain F80594 (serovar 4b), and strain G6006 (CC3, serovar 1/2a), responsible for a large gastroenteritis outbreak in the USA due to chocolate milk. We analysed the genomes and characterized the virulence in vitro and in vivo. Whole-genome sequencing revealed a high conservation of the major virulence genes. Minor deviations of the gene contents were found in the autolysins Ami, Auto, and IspC. Moreover, different ActA variants were present. Strain PF49 and F80594 showed prolonged survival in the liver of infected mice. Invasion and intracellular proliferation were similar for all strains, but the CC1 and CC2 strains showed increased spreading in intestinal epithelial Caco2 cells compared to strain G6006. Overall, this study revealed long-term survival of serovar 4b strains F80594 and PF49 in the liver of mice. Future work will be needed to determine the genes and molecular mechanism behind the long-term survival of L. monocytogenes strains in organs.
A total of 127 extraintestinal Escherichia coli strains of the capsule serotypes Kl, KS, and KlOO from human and animal sources were analyzed for DNA sequences specific for the genes for various adhesins (P fimbriae fpap] and P-related sequences fprs], S fimbriae [s/a)/FlC fimbriae [foc], and type I fimbriae lfim]), aerobactin (aer), and hemolysin (hly). The expression of corresponding virulence factors was also tested. Twenty-four selected strains were analyzed by long-range DNA mapping to evaluate their genetic relationships. DNA sequences for the adhesins were often found in strains not expressing them, while strains with hemolysin and aerobactin genes usually did express them. Different isolates of the same serotype orten expressed different virulence patterns. The use of virulence-associated gene probes for Southern hybridization with genomic DNA fragments separated by pulsed-field gel electrophoresis revealed that a highly heterogeneous restriction fragment length and hybridization pattern existed even within strains of the same serotype. Long-range DNA mapping is therefore useful for the evaluation of genetic relatedness among individual isolates and facilitates the performance of .precise molecular epidemiology.
It is demonstrated that the di‐\(\pi\)‐methane (DPM) rearrangement of carbonyl‐substituted dibenzobarrelene (9,10‐dihydro‐9,10‐ethenoanthracene) derivatives is induced by visible‐light‐induced triplet photosensitization with Ir(ppy)\(_{3}\), Ir(dFppy)\(_{3}\) or 1‐butyl‐7,8‐dimethoxy‐3‐methylalloxazine as catalysts, whereas derivatives that lack carbonyl substituents are photoinert under these conditions. Notably, the products are formed almost quantitatively.
A visual stimulus at a particular location of the visual field may elicit a behavior while at the same time equally salient stimuli in other parts do not. This property of visual systems is known as selective visual attention (SVA). The animal is said to have a focus of attention (FoA) which it has shifted to a particular location. Visual attention normally involves an attention span at the location to which the FoA has been shifted. Here the attention span is measured in Drosophila. The fly is tethered and hence has its eyes fixed in space. It can shift its FoA internally. This shift is revealed using two simultaneous test stimuli with characteristic responses at their particular locations. In tethered flight a wild type fly keeps its FoA at a certain location for up to 4s. Flies with a mutation in the radish gene, that has been suggested to be involved in attention-like mechanisms, display a reduced attention span of only 1s.
PURPOSE:
We aimed to (a) elucidate the concordance of visual assessment of an initial I-ioflupane scan by a human interpreter with comparison to results using a fully automatic semiquantitative method and (b) to assess the accuracy compared to follow-up (f/u) diagnosis established by movement disorder specialists.
METHODS:
An initial I-ioflupane scan was performed in 382 patients with clinically uncertain Parkinsonian syndrome. An experienced reader performed a visual evaluation of all scans independently. The findings of the visual read were compared with semiquantitative evaluation. In addition, available f/u clinical diagnosis (serving as a reference standard) was compared with results of the human read and the software.
RESULTS:
When comparing the semiquantitative method with the visual assessment, discordance could be found in 25 (6.5%) of 382 of the cases for the experienced reader (ĸ = 0.868). The human observer indicated region of interest misalignment as the main reason for discordance. With neurology f/u serving as reference, the results of the reader revealed a slightly higher accuracy rate (87.7%, ĸ = 0.75) compared to semiquantification (86.2%, ĸ = 0.719, P < 0.001, respectively). No significant difference in the diagnostic performance of the visual read versus software-based assessment was found.
CONCLUSIONS:
In comparison with a fully automatic semiquantitative method in I-ioflupane interpretation, human assessment obtained an almost perfect agreement rate. However, compared to clinical established diagnosis serving as a reference, visual read seemed to be slightly more accurate as a solely software-based quantitative assessment.
There is such vast amount of visual information in our surroundings at any time that filtering out the important information for further processing is a basic requirement for any visual system. This is accomplished by deploying attention to focus on one source of sensory inputs to the exclusion of others (Luck and Mangun 2009). Attention has been studied extensively in humans and non human primates (NHPs). In Drosophila, visual attention was first demonstrated in 1980 (Wolf and Heisenberg 1980) but this field remained largely unexplored until recently. Lately, however, studies have emerged that hypothesize the role of attention in several behaviors but do not specify the characteristic properties of attention. So, the aim of this research was to characterize the phenomenon of visual attention in wild-type Drosophila, including both externally cued and covert attention using tethered flight at a torque meter. Development of systematic quantifiable behavioral tests was a key aspect for this which was not only important for analyzing the behavior of a population of wild-type flies but also for comparing the wild-type flies with mutant flies. The latter would help understand the molecular, genetic, and neuronal bases of attention. Since Drosophila provides handy genetic tools, a model of attention in Drosophila will serve to the greater questions about the neuronal circuitry and mechanisms involved which might be analogous to those in primates. Such a model might later be used in research involving disorders of attention. Attention can be guided to a certain location in the visual field by the use of external cues. Here, using visual cues the attention of the fly was directed to one or the other of the two visual half-fields. A simple yet robust paradigm was designed with which the results were easily quantifiable. This paradigm helped discover several interesting properties of the cued attention, the most substantial one being that this kind of external guidance of attention is restricted to the lower part of the fly’s visual field. The guiding cue had an after-effect, i.e. it could occur at least up to 2 seconds before the test and still bias it. The cue could also be spatially separated from the test by at least 20° and yet attract the attention although the extent of the focus of attention (FoA) was smaller than one lower visual half-field. These observations excluded the possibility of any kind of interference between the test and the cue stimuli. Another interesting observation was the essentiality of continuous visibility of the test stimulus but not the cue for effective cuing. When the contrast of the visual scene was inverted, differences in response frequencies and cuing effects were observed. Syndirectional yaw torque responses became more frequent than the antidirectional responses and cuing was no longer effective in the lower visual field with inverted contrast. Interestingly, the test stimulus with simultaneous displacement of two stripes not only effectuated a phasic yaw torque response but also a landing response. A 50 landing response was produced in more than half of the cases whenever a yaw torque response was produced. Elucidation of the neuronal correlates of the cued attention was commenced. Pilot experiments with hydroxyurea (HU) treated flies showed that mushroom bodies were not required for the kind of guidance of attention tested in this study. Dopamine mutants were also tested for the guidance of attention in the lower visual field. Surprisingly, TH-Gal4/UAS-shits1 flies flew like wild-type flies and also showed normal optomotor response during the initial calibration phase of the experiment but did not show any phasic yaw torque or landing response at 18 °C, 25 °C or 30 °C. dumb2 flies that have almost no D1 dopamine receptor dDA1 expression in the mushroom bodies and the central complex (Kim et al. 2007) were also tested and like THGal4/ UAS-shits1 flies did not show any phasic yaw torque or landing response. Since the dopamine mutants did not show the basic yaw torque response for the test the role of dopamine in attention could not be deduced. A different paradigm would be needed to test these mutants. Not only can attention be guided through external cues, it can also be shifted endogenously (covert attention). Experiments with the windows having oscillating stripes nicely demonstrated the phenomenon of covert attention due to the production of a characteristic yaw torque pattern by the flies. However, the results were not easily quantifiable and reproducible thereby calling for a more systematic approach. Experiments with simultaneous opposing displacements of two stripes provide a promising avenue as the results from these experiments showed that the flies had a higher tendency to deliver one type of response than when the responses would be produced stochastically suggesting that attention increased this tendency. Further experiments and analysis of such experiments could shed more light on the mechanisms of covert attention in flies.
Visual Attention in Flies-Dopamine in the Mushroom Bodies Mediates the After-Effect of Cueing
(2016)
Visual environments may simultaneously comprise stimuli of different significance. Often such stimuli require incompatible responses. Selective visual attention allows an animal to respond exclusively to the stimuli at a certain location in the visual field. In the process of establishing its focus of attention the animal can be influenced by external cues. Here we characterize the behavioral properties and neural mechanism of cueing in the fly Drosophila melanogaster. A cue can be attractive, repulsive or ineffective depending upon (e.g.) its visual properties and location in the visual field. Dopamine signaling in the brain is required to maintain the effect of cueing once the cue has disappeared. Raising or lowering dopamine at the synapse abolishes this after-effect. Specifically, dopamine is necessary and sufficient in the αβ-lobes of the mushroom bodies. Evidence is provided for an involvement of the αβ\(_{posterior}\) Kenyon cells.
Visual Blood, a 3D animated computer model to optimize the interpretation of blood gas analysis
(2023)
Acid–base homeostasis is crucial for all physiological processes in the body and is evaluated using arterial blood gas (ABG) analysis. Screens or printouts of ABG results require the interpretation of many textual elements and numbers, which may delay intuitive comprehension. To optimise the presentation of the results for the specific strengths of human perception, we developed Visual Blood, an animated virtual model of ABG results. In this study, we compared its performance with a conventional result printout. Seventy physicians from three European university hospitals participated in a computer-based simulation study. Initially, after an educational video, we tested the participants’ ability to assign individual Visual Blood visualisations to their corresponding ABG parameters. As the primary outcome, we tested caregivers’ ability to correctly diagnose simulated clinical ABG scenarios with Visual Blood or conventional ABG printouts. For user feedback, participants rated their agreement with statements at the end of the study. Physicians correctly assigned 90% of the individual Visual Blood visualisations. Regarding the primary outcome, the participants made the correct diagnosis 86% of the time when using Visual Blood, compared to 68% when using the conventional ABG printout. A mixed logistic regression model showed an odds ratio for correct diagnosis of 3.4 (95%CI 2.00–5.79, p < 0.001) and an odds ratio for perceived diagnostic confidence of 1.88 (95%CI 1.67–2.11, p < 0.001) in favour of Visual Blood. A linear mixed model showed a coefficient for perceived workload of −3.2 (95%CI −3.77 to −2.64) in favour of Visual Blood. Fifty-one of seventy (73%) participants agreed or strongly agreed that Visual Blood was easy to use, and fifty-five of seventy (79%) agreed that it was fun to use. In conclusion, Visual Blood improved physicians’ ability to diagnose ABG results. It also increased perceived diagnostic confidence and reduced perceived workload. This study adds to the growing body of research showing that decision-support tools developed around human cognitive abilities can streamline caregivers’ decision-making and may improve patient care.
Interpreting blood gas analysis results can be challenging for the clinician, especially in stressful situations under time pressure. To foster fast and correct interpretation of blood gas results, we developed Visual Blood. This computer-based, multicentre, noninferiority study compared Visual Blood and conventional arterial blood gas (ABG) printouts. We presented six scenarios to anaesthesiologists, once with Visual Blood and once with the conventional ABG printout. The primary outcome was ABG parameter perception. The secondary outcomes included correct clinical diagnoses, perceived diagnostic confidence, and perceived workload. To analyse the results, we used mixed models and matched odds ratios. Analysing 300 within-subject cases, we showed noninferiority of Visual Blood compared to ABG printouts concerning the rate of correctly perceived ABG parameters (rate ratio, 0.96; 95% CI, 0.92–1.00; p = 0.06). Additionally, the study revealed two times higher odds of making the correct clinical diagnosis using Visual Blood (OR, 2.16; 95% CI, 1.42–3.29; p < 0.001) than using ABG printouts. There was no or, respectively, weak evidence for a difference in diagnostic confidence (OR, 0.84; 95% CI, 0.58–1.21; p = 0.34) and perceived workload (Coefficient, 2.44; 95% CI, −0.09–4.98; p = 0.06). This study showed that participants did not perceive the ABG parameters better, but using Visual Blood resulted in more correct clinical diagnoses than using conventional ABG printouts. This suggests that Visual Blood allows for a higher level of situation awareness beyond individual parameters’ perception. However, the study also highlighted the limitations of today’s virtual reality headsets and Visual Blood.
Personalized oncology is a rapidly evolving area and offers cancer patients therapy options that are more specific than ever. However, there is still a lack of understanding regarding transcriptomic similarities or differences of metastases and corresponding primary sites. Applying two unsupervised dimension reduction methods (t-Distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP)) on three datasets of metastases (n = 682 samples) with three different data transformations (unprocessed, log10 as well as log10 + 1 transformed values), we visualized potential underlying clusters. Additionally, we analyzed two datasets (n = 616 samples) containing metastases and primary tumors of one entity, to point out potential familiarities. Using these methods, no tight link between the site of resection and cluster formation outcome could be demonstrated, or for datasets consisting of solely metastasis or mixed datasets. Instead, dimension reduction methods and data transformation significantly impacted visual clustering results. Our findings strongly suggest data transformation to be considered as another key element in the interpretation of visual clustering approaches along with initialization and different parameters. Furthermore, the results highlight the need for a more thorough examination of parameters used in the analysis of clusters.
Pictorial stimuli can vary on many dimensions, several aspects of which are captured by the term ‘visual complexity.’ Visual complexity can be described as, “a picture of a few objects, colors, or structures would be less complex than a very colorful picture of many objects that is composed of several components.” Prior studies have reported a relationship between affect and visual complexity, where complex pictures are rated as more pleasant and arousing. However, a relationship in the opposite direction, an effect of affect on visual complexity, is also possible; emotional arousal and valence are known to influence selective attention and visual processing. In a series of experiments, we found that ratings of visual complexity correlated with affective ratings, and independently also with computational measures of visual complexity. These computational measures did not correlate with affect, suggesting that complexity ratings are separately related to distinct factors. We investigated the relationship between affect and ratings of visual complexity, finding an ‘arousal-complexity bias’ to be a robust phenomenon. Moreover, we found this bias could be attenuated when explicitly indicated but did not correlate with inter-individual difference measures of affective processing, and was largely unrelated to cognitive and eyetracking measures. Taken together, the arousal-complexity bias seems to be caused by a relationship between arousal and visual processing as it has been described for the greater vividness of arousing pictures. The described arousal-complexity bias is also of relevance from an experimental perspective because visual complexity is often considered a variable to control for when using pictorial stimuli.
It is the aim of this thesis to present a visual body weight estimation, which is suitable for medical applications. A typical scenario where the estimation of the body weight is essential, is the emergency treatment of stroke patients: In case of an ischemic stroke, the patient has to receive a body weight adapted drug, to solve a blood clot in a vessel. The accuracy of the estimated weight influences the outcome of the therapy directly. However, the treatment has to start as early as possible after the arrival at a trauma room, to provide sufficient treatment. Weighing a patient takes time, and the patient has to be moved. Furthermore, patients are often not able to communicate a value for their body weight due to their stroke symptoms. Therefore, it is state of the art that physicians guess the body weight. A patient receiving a too low dose has an increased risk that the blood clot does not dissolve and brain tissue is permanently damaged. Today, about one-third gets an insufficient dosage. In contrast to that, an overdose can cause bleedings and further complications. Physicians are aware of this issue, but a reliable alternative is missing.
The thesis presents state-of-the-art principles and devices for the measurement and estimation of body weight in the context of medical applications. While scales are common and available at a hospital, the process of weighing takes too long and can hardly be integrated into the process of stroke treatment. Sensor systems and algorithms are presented in the section for related work and provide an overview of different approaches.
The here presented system -- called Libra3D -- consists of a computer installed in a real trauma room, as well as visual sensors integrated into the ceiling. For the estimation of the body weight, the patient is on a stretcher which is placed in the field of view of the sensors. The three sensors -- two RGB-D and a thermal camera -- are calibrated intrinsically and extrinsically. Also, algorithms for sensor fusion are presented to align the data from all sensors which is the base for a reliable segmentation of the patient.
A combination of state-of-the-art image and point cloud algorithms is used to localize the patient on the stretcher. The challenges in the scenario with the patient on the bed is the dynamic environment, including other people or medical devices in the field of view.
After the successful segmentation, a set of hand-crafted features is extracted from the patient's point cloud. These features rely on geometric and statistical values and provide a robust input to a subsequent machine learning approach. The final estimation is done with a previously trained artificial neural network.
The experiment section offers different configurations of the previously extracted feature vector. Additionally, the here presented approach is compared to state-of-the-art methods; the patient's own assessment, the physician's guess, and an anthropometric estimation. Besides the patient's own estimation, Libra3D outperforms all state-of-the-art estimation methods: 95 percent of all patients are estimated with a relative error of less than 10 percent to ground truth body weight. It takes only a minimal amount of time for the measurement, and the approach can easily be integrated into the treatment of stroke patients, while physicians are not hindered.
Furthermore, the section for experiments demonstrates two additional applications: The extracted features can also be used to estimate the body weight of people standing, or even walking in front of a 3D camera. Also, it is possible to determine or classify the BMI of a subject on a stretcher. A potential application for this approach is the reduction of the radiation dose of patients being exposed to X-rays during a CT examination.
During the time of this thesis, several data sets were recorded. These data sets contain the ground truth body weight, as well as the data from the sensors. They are available for the collaboration in the field of body weight estimation for medical applications.
The effects of 19 meals of different caloric content on slides on palatability and hypothetical duration of consumption were investigated in 7 patients with anorexia nervosa, 17 patients with bulimia nervosa at the beginning and after 8 weeks of hospital treatment. Nine healthy females served as controls. At the beginning of treatment, palatability of low caloric food was significantly higher and hypothetical duration of consumption of high caloric food was significantly longer in patients when compared to controls. After 8 weeks, in the patients palatability of low caloric food had decreased. Dislike for high caloric food remained stable in anorexics.
Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles—exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate. By pumping a microcavity with a spatially structured light beam, we create a two-dimensional quantum billiard for the exciton-polariton condensate and demonstrate a diabolical point in the spectrum of the billiard eigenstates. The fully reconfigurable geometry of the potential walls controlled by the optical pump enables a striking experimental visualization of the Berry phase associated with the diabolical point. The Berry phase is observed and measured by direct imaging of the macroscopic exciton-polariton probability densities.
Background:
During the last years, (19)F-MRI and perfluorocarbon nanoemulsion (PFC) emerged as a powerful contrast agent methodology to track cells and to visualize inflammation. We applied this new modality to visualize deep tissue abscesses during acute and chronic phase of inflammation caused by Staphylococcus aureus infection.
Methodology and Principal Findings:
In this study, a murine thigh infection model was used to induce abscess formation and PFC or CLIO (cross linked ironoxides) was administered during acute or chronic phase of inflammation. 24 h after inoculation, the contrast agent accumulation was imaged at the site of infection by MRI. Measurements revealed a strong accumulation of PFC at the abscess rim at acute and chronic phase of infection. The pattern was similar to CLIO accumulation at chronic phase and formed a hollow sphere around the edema area. Histology revealed strong influx of neutrophils at the site of infection and to a smaller extend macrophages during acute phase and strong influx of macrophages at chronic phase of inflammation.
Conclusion and Significance:
We introduce (19)F-MRI in combination with PFC nanoemulsions as a new platform to visualize abscess formation in a murine thigh infection model of S. aureus. The possibility to track immune cells in vivo by this modality offers new opportunities to investigate host immune response, the efficacy of antibacterial therapies and the influence of virulence factors for pathogenesis.
Background: During the last years, 19F-MRI and perfluorocarbon nanoemulsion (PFC) emerged as a powerful contrast agent based MRI methodology to track cells and to visualize inflammation. We applied this new modality to visualize deep tissue abscesses during acute and chronic phase of inflammation caused by Staphylococcus aureus infection. Methodology and Principal Findings: In this study, a murine thigh infection model was used to induce abscess formation and PFC or CLIO (cross linked ironoxides) was administered during acute or chronic phase of inflammation. 24 h after inoculation, the contrast agent accumulation was imaged at the site of infection by MRI. Measurements revealed a strong accumulation of PFC at the abscess rim at acute and chronic phase of infection. The pattern was similar to CLIO accumulation at chronic phase and formed a hollow sphere around the edema area. Histology revealed strong influx of neutrophils at the site of infection and to a smaller extend macrophages during acute phase and strong influx of macrophages at chronic phase of inflammation. Conclusion and Significance: We introduce 19F-MRI in combination with PFC nanoemulsions as a new platform to visualize abscess formation in a murine thigh infection model of S. aureus. The possibility to track immune cells in vivo by this modality offers new opportunities to investigate host immune response, the efficacy of antibacterial therapies and the influence of virulence factors for pathogenesis.
Under the intluence of 5-tluoro-uridine, the ultrastructure of the rDNA transcription units in Xenopus oocytes is altered. Whereas part of the matrix units maintains anormal aspect or shows various degrees of inhibition, in a strong proportion of the transcription units the alternating pattern of matrix units and fibril-free spacer regions is no longer recognized. Transcriptional complexes are found along the entire DNP axis, including the regions of the spacers. These observations support biochemical data on transcription in rDNA spacer region.
Staphylococcus aureus is a major threat to public health systems all over the globe. This second most cause of nosocomial infections is able to provoke a wide variety of different types of infection in humans and animals, ranging from superficial skin and skin structure infections to invasive disease like sepsis or pneumonia. But not enough, this pathogen is also notorious in acquiring and/or developing resistance to antimicrobial compounds, thus limiting available treatment options severely. Therefore, development of new compounds and strategies to fight S. aureus is of paramount importance. But since only 1 out of 5 compounds, which entered clinical trials, becomes a drug, the preclinical evaluation of promising compounds has to be reconsidered, too. The aim of this thesis was to address both sides of this problem: first, to improve preclinical testing by incorporating in vivo imaging technologies to the preclinical testing procedure in order to acquire additional and clearer data about efficacy of promising compounds and second, by evaluating lysostaphin, which is a promising, new option to fight S. aureus infections.
The first aim of this thesis focused on the establishment of a dual modality in vivo imaging platform, consisting of Bioluminescence Imaging (BLI) and Magnetic Resonance Imaging (MRI), to offer detailed insights into the course and gravity of S. aureus infection in the murine thigh infection model. Since luciferase-expressing S. aureus strains were generated in former studies and enabled thus bioluminescence imaging of bacterial infection, this technology should be implemented into the compound evaluation platform in order to non-invasively track the bacterial burden over time. MRI, in contrast, was only rarely used in earlier studies to visualize and measure the course of infection or efficacy of anti-bacterial therapy. Thus, the first set of experiments was performed to identify benefits and drawbacks of visualizing S. aureus infections in the mouse model by different MR methods. Native, proton-based MR imaging showed in this regard increased T2 relaxation times in the infected thigh muscles, but it was not possible to define a clear border between infected and uninfected tissue. Iron oxide nanoparticles and perfluorocarbon emulsions, two MR contrast agents or tracer, in contrast, offered this distinction. Iron oxide particles were detected in this regard by their distortion of 1H signal in proton-based MRI, while perfluorocarbon emulsion was identified by 19F MRI. Mammals do not harbor sufficient intrinsic amounts of 19F to deliver specific signal and therefore, 19F MR imaging visualizes only the signal of administered perfluorocarbon emulsion. The in vivo accumulation of perfluorocarbon emulsion can be imaged by 19F MRI and overlayed on a simultaneously acquired 1H MR image, which shows the anatomical context in clear detail. Since this is advantageous compared to contrast agent based MR methods like iron oxide particle-based MRI, further experiments were performed with perfluorocarbon emulsions and 19F MRI.
Experimental studies to elucidate the accumulation of perfluorocarbon emulsion at the site of infection showed robust 19F MR signals after administration between day 2 and at least day 8 p.i.. Perfluorocarbon emulsion accumulated in all investigated mice in the shape of a ‘hollow sphere’ at the rim of the abscess area and the signal remained stable as long as the infection prevailed. In order to identify the mechanism of accumulation, flow cytometry, cell sorting and histology studies were performed. Flow cytometry and cell sorting analysis of immune cells at the site of infection showed that neutrophils, monocytes, macrophages and dendritic cells carried contrast media at the site of infection with neutrophils accounting for the overwhelming portion of perfluorocarbon signal. In general, most of the signal was associated with immune cells, thus indicating specific immune cell dependent accumulation. Histology supported this observation since perfluorocarbon emulsion related fluorescence could only be visualized in close proximity to immune cell nuclei.
After establishing and testing of 19F MRI with perfluorocarbon emulsions as infection imaging modality, the effects of antibiotic therapy upon MR signal was investigated in order to evaluate the capability of this modality for preclinical testing procedure. Thus, the efficacy of vancomycin and linezolid, two clinically highly relevant anti - S. aureus compounds, were tested in the murine thigh infection model. Both of them showed reduction of the colony forming units and bioluminescence signal, but also of perfluorocarbon emulsion accumulation strength and volume at the site of infection, which was visualized and quantified by 19F MRI. The efficacy pattern with linezolid being more efficient in clearing bacterial infection was shown similarly by all three methods. In consequence, 19F MRI with perfluorocarbon emulsion as MR tracer proved to be capable to visualize antibacterial therapy in preclinical testing models.
The next step was consequently to evaluate a promising new compound against S. aureus infections. Thus, lysostaphin, an endo-peptidase that cleaves the cell wall of S. aureus, was tested in different concentrations alone or in combination with oxacillin for efficacy in murine thigh and catheter associated infection models. Lysostaphin only in the concentration of 5 mg/kg body weight or combined with oxacillin in the concentration of 2 mg/kg showed strong reduction of bacterial burden by colony forming unit determination and bioluminescence imaging in both models. The perfluorocarbon accumulation was investigated in the thigh infection model by 19F MRI and was strongly reduced in terms of volume and signal strength in both above-mentioned groups. In general, lysostaphin showed comparable or superior efficacy than vancomycin or oxacillin alone. Therefore, further development of lysostaphin for the treatment of S. aureus infections is recommended by these experiments. Overall, the antibiotic efficacy pattern of all applied antibiotic regimens was similar with all three applied methods, demonstrating the usefulness of MRI for antibiotic efficacy testing. Importantly, treatment with oxacillin either alone or in combination with lysostaphin resulted in stronger perfluorocarbon emulsion accumulation at the site of infection than expected compared to the results from bioluminescence imaging and colony forming unit determination. This might be an indication for immunomodulatory properties of oxacillin.
Further murine infection experiments demonstrated in this context a differential release of cytokine and chemokines in the infected thigh muscle in dependence of the applied antibacterial therapy. Especially treatment with oxacillin, but to a less degree with minocycline or linezolid, too, exhibited high levels of various cytokines and chemokines, although they reduced the bacterial burden efficiently. In consequence, possible immunomodulatory effects of antibacterial compounds have to be taken into account for future applications of imaging platforms relying on the visualization of the immune response. However, this observation opens a new field for these imaging modalities since it might be extraordinary interesting to study the immunomodulatory effects of compounds or even bacterial factors in vivo. And finally, a two modality imaging platform which combines methods to visualize on the one hand the bacterial burden and on the other hand the immune response offers an innovative, new platform to study host-pathogen interaction in vivo in a non-invasive fashion.
In summary, it could be shown that perfluorocarbon emulsions accumulate in immune cells at the site of infection in the murine S. aureus thigh infection model. The accumulation pattern shapes a ‘hollow sphere’ at the rim of the abscess area and its size and perfluorocarbon content is dependent on the severity of disease and/or efficacy of antibiotic therapy. Thus, 19F MRI with perfluorocarbon emulsions is a useful imaging modality to visualize sites and course of infection as well as to evaluate promising antibacterial drug candidates. Furthermore, since the accumulation of tracer depends on immune cells, it might be additionally interesting for studies regarding the immune response to infections, auto-immune diseases or cancer, but also to investigate the efficacy of immunomodulatory compounds and immunization.
The Transforming Growth Factor (TGF) superfamily of cytokines and their serine/threonine kinase receptors play an important role in the regulation of cell division, differentiation, adhesion, migration, organization, and death. Smad proteins are the major intracellular signal transducers for the TGF receptor superfamily that mediate the signal from the membrane into the nucleus. Bone Morphogenetic Protein-4 (BMP-4) is a representative of the TGF superfamily, which regulates the formation of teeth, limbs and bone, and also plays a role in fracture repair. Binding of BMP-4 to its receptor stimulates phosphorylation of Smad1, which subsequently recruits Smad4. A hetero-oligomeric complex consisting of Smad1 and Smad4 then translocates into the nucleus and regulates transcription of target genes by interacting with transcription factors. Although the individual steps of the signaling cascade from the receptor to the nucleus have been identified, the exact kinetics and the rate limiting step(s) have remained elusive. Standard biochemical techniques are not suitable for resolving these issues, as they do not offer sufficiently high sensitivity and temporal resolution. In this study, advanced optical techniques were used for direct visualization of Smad signaling in live mammalian cells. Novel fluorescent biosensors were developed by fusing cyan and yellow fluorescent proteins to the signaling molecules Smad1 and Smad4. By measuring Fluorescence Resonance Energy Transfer (FRET) between the two fluorescent proteins, the kinetics of BMP/Smad signaling was unraveled. A rate-limiting delay of 2 - 5 minutes occurred between BMP receptor stimulation and Smad1 activation. A similar delay was observed in the complex formation between Smad1 and Smad4. Further experimentation indicated that the delay is dependent on the Mad homology 1 (MH1) domain of Smad1. These results give new insights into the dynamics of the BMP receptor – Smad1/4 signaling process and provide a new tool for studying Smads and for testing inhibitory drugs.
Visualization of type I immunity using bicistronic IFN-gamma reporter mice in vitro and in vivo
(2006)
IFN-γ is the signature cytokine of Th1 and CD8+ effector cells generated in type I immune responses against pathogens, such as Influenza virus, Sendai virus and the intracellular protozoan parasite Toxoplasma gondii. Understanding the regulation of IFN-γ is critical for the manipulation of immune responses, prevention of immunopathology and for vaccine design. In the present thesis, IFN-γ expression by CD4+ and CD8+ T cells was characterized in detail and the requirement of IFN-γ receptor mediated functions for IFN-γ expression was assessed. Bicistronic IFN-γ-eYFP reporter mice, which allow direct identification and isolation of live IFN-γ expressing cells, were used to visualize IFN-γ expression in vitro and in vivo after infection with the afore mentioned pathogens. Expression of the IFN-γ-eYFP reporter by CD4+ and CD8+ T cells was broadly heterogeneous in vitro and in vivo after infection. Increased expression of the reporter correlated positively with the abundance of IFN-γ transcripts and IFN-γ protein production upon stimulation. eYFP reporter brightness reflected the potential for IFN-γ production, but actual secretion was largely dependent on antigenic stimulation. Increased expression of the reporter also correlated with enhanced secretion of additional proinflammatory cytokines and chemokines and cell surface expression of markers that indicate recent activation. Highly eYFP fluorescent cells were generally more differentiated and their anatomical distribution was restricted to certain tissues. The anatomical restriction depended on the pathogen. IFN-γ expressing CD4+ and CD8+ T cells were generated in IFN-γ receptor deficient reporter mice after infection with Sendai virus or Toxoplasma gondii. However, in the absence of IFN-γ receptor mediated functions, the frequency and brightness of the eYFP reporter expression was altered. Dual BM chimeric mice, reconstituted with wild-type and IFN-γ receptor deficient reporter BM, revealed a T cell-intrinsic requirement for the IFN-γ receptor for optimal IFN-γ expression. Reporter fluorescence intensities were regulated independently of IFN-γ receptor mediated functions. Finally, we propose a model for IFN-γ expression by CD4+ and CD8+ T cells. 2. SUMMARY 10 In summary, the expression of IFN-γ is differentially regulated in CD4+ and CD8+ T cells and after viral or protozoan infections. Additionally, the role of IFN-γ receptor mediated functions for the expression of IFN-γ was determined.
The presynaptic active zone (AZ) of chemical synapses is a highly dynamic compartment where synaptic vesicle fusion and neurotransmitter release take place. During evolution the AZ was optimized for speed, accuracy, and reliability of chemical synaptic transmission in combination with miniaturization and plasticity. Single-molecule localization microscopy (SMLM) offers nanometer spatial resolution as well as information about copy number, localization, and orientation of proteins of interest in AZs. This type of imaging allows quantifications of activity dependent AZ reorganizations, e.g., in the context of presynaptic homeostatic potentiation. In combination with high-pressure freezing and optogenetic or electrical stimulation AZs can be imaged with millisecond temporal resolution during synaptic activity. Therefore SMLM allows the determination of key parameters in the complex spatial environment of AZs, necessary for next generation simulations of chemical synapses with realistic protein arrangements.
The size of the synaptic subcomponents falls below the limits of visible light microscopy. Despite new developments in advanced microscopy techniques, the resolution of transmission electron microscopy (TEM) remains unsurpassed. The requirements of tissue preservation are very high, and human post mortem material often does not offer adequate quality. However, new reprogramming techniques that generate human neurons in vitro provide samples that can easily fulfill these requirements. The objective of this study was to identify the culture technique with the best ultrastructural preservation in combination with the best embedding and contrasting technique for visualizing neuronal elements. Two induced neural stem cell lines derived from healthy control subjects underwent differentiation either adherent on glass coverslips, embedded in a droplet of highly concentrated Matrigel, or as a compact neurosphere. Afterward, they were fixed using a combination of glutaraldehyde (GA) and paraformaldehyde (PFA) followed by three approaches (standard stain, Ruthenium red stain, high contrast en-bloc stain) using different combinations of membrane enhancing and contrasting steps before ultrathin sectioning and imaging by TEM. The compact free-floating neurospheres exhibited the best ultrastructural preservation. High-contrast en-bloc stain offered particularly sharp staining of membrane structures and the highest quality visualization of neuronal structures. In conclusion, compact neurospheres growing under free-floating conditions in combination with a high contrast en-bloc staining protocol, offer the optimal preservation and contrast with a particular focus on visualizing membrane structures as required for analyzing synaptic structures.
Honeybees can easily be trained to perform different types of discrimination tasks under controlled laboratory conditions. This review describes a range of experiments carried out with free-flying forager honeybees under such conditions. The research done over the past 30 or so years suggests that cognitive abilities (learning and perception) in insects are more intricate and flexible than was originally imagined. It has become apparent that honeybees are capable of a variety of visually guided tasks, involving decision making under challenging situations: this includes simultaneously making use of different sensory modalities, such as vision and olfaction, and learning to use abstract concepts such as “sameness” and “difference.” Many studies have shown that decision making in foraging honeybees is highly flexible. The trained animals learn how to solve a task, and do so with a high accuracy, but when they are presented with a new variation of the task, they apply the learnt rules from the earlier setup to the new situation, and solve the new task as well. Honeybees therefore not only feature a rich behavioral repertoire to choose from, but also make decisions most apt to the current situation. The experiments in this review give an insight into the environmental cues and cognitive resources that are probably highly significant for a forager bee that must continually make decisions regarding patches of resources to be exploited.
Modulation of sensorimotor rhythms (SMR) was suggested as a control signal for brain-computer interfaces (BCI). Yet, there is a population of users estimated between 10 to 50% not able to achieve reliable control and only about 20% of users achieve high (80–100%) performance. Predicting performance prior to BCI use would facilitate selection of the most feasible system for an individual, thus constitute a practical benefit for the user, and increase our knowledge about the correlates of BCI control. In a recent study, we predicted SMR-BCI performance from psychological variables that were assessed prior to the BCI sessions and BCI control was supported with machine-learning techniques. We described two significant psychological predictors, namely the visuo-motor coordination ability and the ability to concentrate on the task. The purpose of the current study was to replicate these results thereby validating these predictors within a neurofeedback based SMR-BCI that involved no machine learning.Thirty-three healthy BCI novices participated in a calibration session and three further neurofeedback training sessions. Two variables were related with mean SMR-BCI performance: (1) a measure for the accuracy of fine motor skills, i.e., a trade for a person’s visuo-motor control ability; and (2) subject’s “attentional impulsivity”. In a linear regression they accounted for almost 20% in variance of SMR-BCI performance, but predictor (1) failed significance. Nevertheless, on the basis of our prior regression model for sensorimotor control ability we could predict current SMR-BCI performance with an average prediction error of M = 12.07%. In more than 50% of the participants, the prediction error was smaller than 10%. Hence, psychological variables played a moderate role in predicting SMR-BCI performance in a neurofeedback approach that involved no machine learning. Future studies are needed to further consolidate (or reject) the present predictors.
Previous research showed that full body ownership illusions in virtual reality (VR) can be robustly induced by providing congruent visual stimulation, and that congruent tactile experiences provide a dispensable extension to an already established phenomenon. Here we show that visuo-tactile congruency indeed does not add to already high measures for body ownership on explicit measures, but does modulate movement behavior when walking in the laboratory. Specifically, participants who took ownership over a more corpulent virtual body with intact visuo-tactile congruency increased safety distances towards the laboratory's walls compared to participants who experienced the same illusion with deteriorated visuo-tactile congruency. This effect is in line with the body schema more readily adapting to a more corpulent body after receiving congruent tactile information. We conclude that the action-oriented, unconscious body schema relies more heavily on tactile information compared to more explicit aspects of body ownership.
Neurofibromatosis type 1 (NF1) is a genetic multisystemic autosomal dominant disorder determining reduced life expectancy due to higher risk of developing benign and malignant tumors. Low levels of vitamin D and reduced bone mineral density (BMD) have been reported in young patients with NF1. However, correlation between vitamin D and NF1 phenotype needs to be elucidated. Aim of this study was to assess vitamin D levels and bone metabolism in NF1 patients, analyzing potential correlations with clinical phenotype. A cross-sectional study was carried out in a monocentric series of NF1 patients, evaluating genotype, clinical phenotype, BMD, biochemical evaluation with focus on serum 25OH-vitamin D, parathyroid hormone (PTH), calcium and phosphate levels. Correlations between clinical manifestations, neurofibromas, and vitamin D status have been studied in comparison with healthy controls. 31 NF1 adult patients were matched for sex, age and body mass index with 31 healthy controls. A significantly difference in vitamin D level emerged in NF1 patients compared to controls. Interestingly low vitamin D levels correlated with a more aggressive phenotype and with a bigger size of neurofibromas. These data underline that vitamin D deficiency/insufficiency may play a role in clinical severity of neurofibromas in patients with NF1, suggesting the need to check bone status and replace vitamin D in these patients.
(1) Background: Evidence has accumulated that patients with anorexia nervosa (AN) are at higher risk for vitamin D deficiency than healthy controls. In epidemiologic studies, low 25(OH) vitamin D (25(OH)D) levels were associated with depression. This study analyzed the relationship between 25(OH)D serum levels in adolescent patients and AN and depressive symptoms over the course of treatment. (2) Methods: 25(OH)D levels and depressive symptoms were analyzed in 93 adolescent (in-)patients with AN from the Anorexia Nervosa Day patient versus Inpatient (ANDI) multicenter trial at clinic admission, discharge, and 1 year follow up. Mixed regression models were used to analyze the relationship between 25(OH)D levels and depressive symptoms assessed by the Beck Depression Inventory (BDI-II). (3) Results: Although mean 25(OH)D levels constantly remained in recommended ranges (≥50 nmol/L) during AN treatment, levels decreased from (in)patient admission to 1 year follow up. Levels of 25(OH)D were neither cross-sectionally, prospectively, nor longitudinally associated with the BDI-II score. (4) Conclusions: This study did not confirm that 25(OH)D levels are associated with depressive symptoms in patients with AN. However, increasing risks of vitamin D deficiency over the course of AN treatment indicate that clinicians should monitor 25(OH)D levels.
Background: Different parameters have been determined for prediction of treatment outcome in hepatitis c virus genotype 1 infected patients undergoing pegylated interferon, ribavirin combination therapy. Results on the importance of vitamin D levels are conflicting. In the present study, a comprehensive analysis of vitamin D levels before and during therapy together with single nucleotide polymorphisms involved in vitamin D metabolism in the context of other known treatment predictors has been performed.
Methods: In a well characterized prospective cohort of 398 genotype 1 infected patients treated with pegylated interferon-alpha and ribavirin for 24-72 weeks (INDIV-2 study) 25-OH-vitamin D levels and different single nucleotide polymorphisms were analyzed together with known biochemical parameters for a correlation with virologic treatment outcome.
Results: Fluctuations of more than 5 (10) ng/ml in 25-OH-vitamin D-levels have been observed in 66 (39) % of patients during the course of antiviral therapy and neither pretreatment nor under treatment 25-OH-vitamin D-levels were associated with treatment outcome. The DHCR7-TT-polymorphism within the 7-dehydrocholesterol-reductase showed a significant association (P = 0.031) to sustained viral response in univariate analysis. Among numerous further parameters analyzed we found that age (OR = 1.028, CI = 1.002-1.056, P = 0.035), cholesterol (OR = 0.983, CI = 0.975-0.991, P<0.001), ferritin (OR = 1.002, CI = 1.000-1.004, P = 0.033), gGT (OR = 1.467, CI = 1.073-2.006, P = 0.016) and IL28B-genotype (OR = 2.442, CI = 1.271-4.695, P = 0.007) constituted the strongest predictors of treatment response.
Conclusions: While 25-OH-vitamin D-levels levels show considerable variations during the long-lasting course of antiviral therapy they do not show any significant association to treatment outcome in genotype 1 infected patients.
The biology of vitamin D3 is well defined, as are the effects of its active metabolites on various cells, including mesenchymal stromal/stem cells (MSCs). However, the biological potential of its precursor, cholecalciferol (VD3), has not been sufficiently investigated, although its significance in regenerative medicine — mainly in combination with various biomaterial matrices — has been recognized. Given that VD3 preconditioning might also contribute to the improvement of cellular regenerative potential, the aim of this study was to investigate its effects on bone marrow (BM) MSC functions and the signaling pathways involved. For that purpose, the influence of VD3 on BM-MSCs obtained from young human donors was determined via MTT test, flow cytometric analysis, immunocytochemistry, and qRT-PCR. Our results revealed that VD3, following a 5-day treatment, stimulated proliferation, expression of pluripotency markers (NANOG, SOX2, and Oct4), and osteogenic differentiation potential in BM-MSCs, while it reduced their senescence. Moreover, increased sirtuin 1 (SIRT1) expression was detected upon treatment with VD3, which mediated VD3-promoted osteogenesis and, partially, the stemness features through NANOG and SOX2 upregulation. In contrast, the effects of VD3 on proliferation, Oct4 expression, and senescence were SIRT1-independent. Altogether, these data indicate that VD3 has strong potential to modulate BM-MSCs' features, partially through SIRT1 signaling, although the precise mechanisms merit further investigation.
Myeloid-derived suppressor cells (MDSCs) represent a major population controlling T cell immune responses. However, little is known about their molecular requirements for homing and T cell interaction to mediate suppression. Here, we investigated the functional role of the homing and collagen IV receptor VLA-1 (α1β1-integrin) on in vitro GM-CSF generated murine MDSCs from wild-type (WT) and CD49a/α1-integrin (Itga1\(^{−/−}\)) gene-deficient mice. Here, we found that effector (Teff) but not naive (Tn) CD4\(^+\) T cells express VLA-1 and monocytes further up-regulated their expression after culture in GM-CSF when they differentiated into the monocytic subset of resting MDSCs (R-MDSCs). Subsequent activation of R-MDSCs by LPS+IFN-γ (A-MDSCs) showed increased in vitro suppressor potential, which was independent of VLA-1. Surprisingly, VLA-1 deficiency did not influence A-MDSC motility or migration on collagen IV in vitro. However, interaction times of Itga1\(^{−/−}\) A-MDSCs with Teff were shorter than with WT A-MDSCs on collagen IV but not on fibronectin substrate in vitro. After injection, A-MDSCs homed to the splenic red pulp where they co-localized with Teff and showed immediate suppression already after 6 h as shown by inhibition of T cell proliferation and induction of apoptosis. Injection of A-MDSCs from Itga1\(^{−/−}\) mice showed equivalent homing into the spleen but a reduced suppressive effect. Interaction studies of A-MDSCs with Teff in the subcapsular red pulp with intravital two-photon microscopy revealed also here that MDSC motility and migration parameters were not altered by VLA-1 deficiency, but the interaction times with Teff were reduced. Together, our data point to a new role of VLA-1 adhesion to collagen IV as a prerequisite for extended contact times with Teff required for suppression.
Ownership and usage of personal voice assistant devices like Amazon Echo or Google Home have increased drastically over the last decade since their market launch. This thesis builds upon existing computers are social actors (CASA) and media equation research that is concerned with humans displaying social reactions usually exclusive to human-human interaction when interacting with media and technological devices. CASA research has been conducted with a variety of technological devices such as desktop computers, smartphones, embodied virtual agents, and robots. However, despite their increasing popularity, little empirical work has been done to examine social reactions towards these personal stand-alone voice assistant devices, also referred to as smart speakers. Thus, this dissertation aims to adopt the CASA approach to empirically evaluate social responses to smart speakers. With this goal in mind, four laboratory experiments with a total of 407 participants have been conducted for this thesis. Results show that participants display a wide range of social reactions when interacting with voice assistants. This includes the utilization of politeness strategies such as the interviewer-bias, which led to participants giving better evaluations directly to a smart speaker device compared to a separate computer. Participants also displayed prosocial behavior toward a smart speaker after interdependence and thus a team affiliation had been induced. In a third study, participants applied gender stereotypes to a smart speaker not only in self-reports but also exhibited conformal behavior patterns based on the voice the device used. In a fourth and final study, participants followed the rule of reciprocity and provided help to a smart speaker device that helped them in a prior interaction. This effect was also moderated by subjects’ personalities, indicating that individual differences are relevant for CASA research. Consequently, this thesis provides strong empirical support for a voice assistants are social actors paradigm. This doctoral dissertation demonstrates the power and utility of this research paradigm for media psychological research and shows how considering voice assistant devices as social actors lead to a more profound understanding of voice-based technology. The findings discussed in this thesis also have implications for these devices that need to be carefully considered both in future research as well as in practical design.
For many active volcanoes all over the world a civil protection program, normally combined with hazard maps, exists. Optimising of hazard maps and the associated hazard assessment implies a detailed knowledge of the volcanostratigraphy, because the deposits provoke information on the potential behaviour during a new activity cycle. Pyroclastic deposits, however, may vary widely in thickness and distribution over very short lateral distances. High resolution characterisation of single strata often cannot be archived, if solely sedimentological and geochemical methods are used. Gamma-ray measurements taken in the field combined with grain-size depended magnetic susceptibility measurements made in the laboratory are used in this work to optimise the resolution of volcanostratigraphic investigations. The island of Vulcano is part of the Aeolian Archipelago sited of the northern coast of Sicily. La Fossa cone is the active centre of Vulcano, where fumarolic and seismic activity can be observed. The cone was built up during the last 6,000 years, whereby the last eruption period is dated to historic times (1888-1890). For the tuff cone La Fossa the most likely volcanic hazards are the emplacement of pyroclastic deposits as well as gas hazards (especially SOx and CO2), due to this the detailed knowledge of the stratigraphy is mandatory. Most of the population resides in Vulcano Porto and the nearby sited peninsula of Vulcanello, which are highly endangered locations for a future eruption scenario. Measurements, made in standard outcrops, allow a characterisation of the successions Punte Nere, Tufi Varicolori, Palizzi, Commenda, and Cratere Attuale. A discrimination of all successions by solely one of the methods is rarely possible. In some cases, however, the combination of the methods leads to clear results. It can also be noticed that the exposition as well as the sedimentation type (wet-surge or dry-surge deposits) affect the measurements. In general it can be assumed that the higher the magma is evolved the higher the g -ray values and the lower the susceptibility values. Measurements from the Wingertsberg (Laacher See deposits, Eifel, W-Germany) show clearly that a higher degree of magma evolution correlates with lower susceptibility and higher gamma-ray values. Variations of the values can be observed not only by the change of the degree of magmatic evolution but also by the inhomogeneous deposition conditions. Particularly the gamma-ray measurements show lower values for the wet-surge deposits than for the dry-surge deposits, even though the erupted material has the same geochemical composition. This can be explained especially by reactions inside of the moist eruption cloud and short-time after deposition, when easily soluble elements like K, U, and Th can be leached by these aggressive fluids. Even extended exposition and high water content can provoke depletion of various elements within the complete or parts of the outcrop, too. If the deposits are affected by a fumarolic activity especially the susceptibility values show significant variations, whereas in general extreme low values are observed. Contamination of deposits also can occur, if they are overlain by weathered deposits of higher concentration of K, U, and Th. Weathering and mobilisation within the upper deposits can generate an element enrichment within the lower deposits. In general the element ratios of the barried underlying deposits are less affected than the exposed ones. After gauging the values of the well defined succession for standard outcrops undefined outcrops were measured. These outcrops are not clearly classified by sedimentological and geochemical methods, thus a correlation with the combined geophysical methods is useful. In general the combination of the methods allows a correlation, although in some cases more than one interpretation is possible. But in connection with time marker horizons as well as sedimentological features an interpretation is feasible. These situations show that a classification solely based on geophysical methods is possible for many cases but, if the volcanic system is more complex, a combination with sedimentological and geochemical methods may be needed. The investigations on Vulcano, documented in this work, recommend a re-interpretation of the dispersial of some successions of La Fossa cone, especially the presumption that Tufi Varicolori only exist inside of the Caldera of La Fossa. As a consequence the eruption and energy model especially for Tufi Varicolori have to be reviewed.
In this study, we examined the conditional indirect and direct relations of pain-related cognitions to depression. Subjective helplessness was included as presumably mediating the relations of catastrophizing and thought suppression to depression due to motivational deficits. In addition, moderating effects of dispositional action versus state orientation were analyzed, whereby state orientation indicates volitional deficits in coping with distress. The study was based on self-report data from 536 patients with chronic non-specific low back pain at the beginning of inpatient rehabilitation. Moderated mediation analyses were performed. The indirect catastrophizing- and thought suppression-depression relations were (partially) mediated by subjective helplessness; and moderated by failure-related action versus state orientation. Moreover, action versus state orientation moderated the direct relation of thought suppression to depression. Results suggest that catastrophizing, thought suppression, and subjective helplessness do not lead to depression unless associated with self-regulatory inability (i.e., state orientation). In contrast, action-oriented patients more effectively self-regulate pain-related emotions, disengage from rumination, and distract from pain and thus better avoid the debilitating effects of negative pain-related cognitions on depression. Future research and treatment may more strongly focus on the role of motivational and volitional deficits underlying learned helplessness and depression in chronic pain.
In contrast to the plasma membrane, the vacuole membrane has not yet been associated with electrical excitation of plants. Here, we show that mesophyll vacuoles from Arabidopsis sense and control the membrane potential essentially via the K\(^+\)-permeable TPC1 and TPK channels. Electrical stimuli elicit transient depolarization of the vacuole membrane that can last for seconds. Electrical excitability is suppressed by increased vacuolar Ca\(^{2+}\) levels. In comparison to wild type, vacuoles from the fou2 mutant, harboring TPC1 channels insensitive to luminal Ca\(^{2+}\), can be excited fully by even weak electrical stimuli. The TPC1-loss-of-function mutant tpc1-2 does not respond to electrical stimulation at all, and the loss of TPK1/TPK3-mediated K\(^{+}\) transport affects the duration of TPC1-dependent membrane depolarization. In combination with mathematical modeling, these results show that the vacuolar K\(^+\)-conducting TPC1 and TPK1/TPK3 channels act in concert to provide for Ca\(^{2+}\)- and voltage-induced electrical excitability to the central organelle of plant cells.
The present study was performed to qua ntify the distribution of a peptide neurotransmitter after microinjection into the medial preoptic area (POM), using a technique suitable for conscious animal preparations. The results indicate that only 50-ni volumes of injected tracer were sufficiently localized with 77 ± 9% recovery in the POM. Injections of higher volumes resulted in an increasing spread of tracer into distant anatomical regions and structures, including the needle tract and cerebral ventricles. The amount of tracer localized in the POM decreased to 38±4% (200 nl) (P < 0.05) and 41 ±8% (500 nl) (P <0.05), respectively. The data suggest that the volume of injection is critical for intraparenchymal injections into structures of a diameter of I mm or less, such as the POM and should not exceed 50 nl in conscious animal preparations.
Purpose: The metabolically most active lesion in 2-deoxy-2-(\(^{18}\)F)fluoro-D-glucose (\(^{18}\)F-FDG) PET/CT can predict progression-free survival (PFS) in patients with medullary thyroid carcinoma (MTC) starting treatment with the tyrosine kinase inhibitor (TKI) vandetanib. However, this metric failed in overall survival (OS) prediction. In the present proof of concept study, we aimed to explore the prognostic value of intratumoral textural features (TF) as well as volumetric parameters (total lesion glycolysis, TLG) derived by pre-therapeutic \(^{18}\)F-FDG PET.
Methods: Eighteen patients with progressive MTC underwent baseline \(^{18}\)F-FDG PET/CT prior to and 3 months after vandetanib initiation. By manual segmentation of the tumor burden at baseline and follow-up PET, intratumoral TF and TLG were computed. The ability of TLG, imaging-based TF, and clinical parameters (including age, tumor marker doubling times, prior therapies and RET (rearranged during transfection) mutational status) for prediction of both PFS and OS were evaluated.
Results: The TF Complexity and the volumetric parameter TLG obtained at baseline prior to TKI initiation successfully differentiated between low- and high-risk patients. Complexity allocated 10/18 patients to the high-risk group with an OS of 3.3y (vs. low-risk group, OS=5.3y, 8/18, AUC=0.78, P=0.03). Baseline TLG designated 11/18 patients to the high-risk group (OS=3.5y vs. low-risk group, OS=5y, 7/18, AUC=0.83, P=0.005). The Hazard Ratio for cancer-related death was 6.1 for Complexity (TLG, 9.5). Among investigated clinical parameters, the age at initiation of TKI treatment reached significance for PFS prediction (P=0.02, OS, n.s.).
Conclusions: The TF Complexity and the volumetric parameter TLG are both independent parameters for OS prediction.
The interim reporting process provides decision-useful information to investors and market participants. However the legal circumstances of external interim auditor reviews differ worldwide. A mandatory review rule in the US as opposed to a contrary decision of the German legislator raises the question of the cost-benefit-relation of auditor reviews. Using a German sample of 1,023 firm-year observations from 2007 to 2010, I extract the costs and the benefits of voluntary semi-annual reviews. The unique German legal environment makes it possible to split the cost effect of a review in the price effect (included in audit-related fees) and a possible reduction of audit fees resulting from an improved year-around audit process. I observe a significant increase of audit and audit-related fees of around 14.5% (total fee effect). Additionally, the study provides evidence on declining audit fees for reviewed firms as compared to a matched sample of non-reviewed firms. The effect of an interim review on quarterly earnings quality – using discretionary accruals as an earning management proxy – shows no significant influence.
This study investigates the effect of the error announcement risk on the demand for voluntary interim auditor reviews. Material changes in the German legal environment in 2007 introduced an enforcement system for semi-annual financial reports. The demand for voluntary semi-annual reviews increased significantly from 0.8% in 2006 to 14.6% in 2007 and increased further to 19.5% until 2010 for a sample of 1,278 firm-year observations. This study addresses the question whether the enforcement structure and the resulting error announcement risk exposure have an influence on voluntary external monitoring. After controlling for agency costs, the corporate governance structure, and selected review cost factors, results of a logistic regression analysis show a positive influence of error announcement risk on the likelihood of engaging an auditor to review the semi-annual interim report. The findings contribute to the literature by demonstrating that the quality of the enforcement system and the risk of error findings influence the review decision of the board of directors positively.
In 2004 German legislation established the Financial Reporting Enforcement Panel. In 147 cases since then, the panel has ordered the announcement of errors in previously disclosed and audited financial statements of German firms. We use this unique dataset to evaluate the consequences of increasing earnings management over time on enforcement releases and their recognition in audit fees. Ettredge et al. (2010) provide evidence on a phenomenon called ‘balance sheet bloat’ that is due to income increasing earnings management and later influences the disclosure of misstated financial statements. Thus, the evidence of earnings management recognition in audit fees (Abbott et al. 2006) and the hypothesis of future information content in fees by Stanley (2011) leads us to hypothesize that auditors recognize increasing audit risk in audit fees before the enforcement process starts. We extend related earnings management and audit fee literature by modeling the development of earnings management within the misstatement firms and systematically link it to auditor reactions. We find significant predictive power of different commonly used accrual measures for enforcement releases in the period prior and up to the misstatement period. In this period of time, we also observe an audit fee increase, e.g. the recognition of increased audit risk. We investigate an audit fee effect after the misstatement period but find no significant relation.
It is shown that the rate of convergence in the von Mises conditions of extreme value theory determines the distance of the underlying distribution function F from a generalized Pareto distribution. The distance is measured in terms of the pertaining densities with the limit being ultimately attained if and only if F is ultimately a generalized Pareto distribution. Consequently, the rate of convergence of the extremes in an lid sample, whether in terms of the distribution of the largest order statistics or of corresponding empirical truncated point processes, is determined by the rate of convergence in the von Mises condition. We prove that the converse is also true.
Background and Purpose
In animal models, von Willebrand factor (VWF) is involved in thrombus formation and propagation of ischemic stroke. However, the pathophysiological relevance of this molecule in humans, and its potential use as a biomarker for the risk and severity of ischemic stroke remains unclear. This study had two aims: to identify predictors of altered VWF levels and to examine whether VWF levels differ between acute cerebrovascular events and chronic cerebrovascular disease (CCD).
Methods
A case–control study was undertaken between 2010 and 2013 at our University clinic. In total, 116 patients with acute ischemic stroke (AIS) or transitory ischemic attack (TIA), 117 patients with CCD, and 104 healthy volunteers (HV) were included. Blood was taken at days 0, 1, and 3 in patients with AIS or TIA, and once in CCD patients and HV. VWF serum levels were measured and correlated with demographic and clinical parameters by multivariate linear regression and ANOVA.
Results
Patients with CCD (158±46%) had significantly higher VWF levels than HV (113±36%, P<0.001), but lower levels than AIS/TIA patients (200±95%, P<0.001). Age, sex, and stroke severity influenced VWF levels (P<0.05).
Conclusions
VWF levels differed across disease subtypes and patient characteristics. Our study confirms increased VWF levels as a risk factor for cerebrovascular disease and, moreover, suggests that it may represent a potential biomarker for stroke severity, warranting further investigation.
This compilation focuses on adolescent mental disorders and their prevention. It comprises three distinct studies, each contributing to a deeper understanding of this critical topic. This work addresses a critical gap in the understanding of, and approach to, adolescent mental health, and as a result reveals a critically important and urgently needed policy implication for action. The thematic structure of these studies begins with an examination of the epidemiology of child and adolescent mental disorders. Baseline data were collected from N = 877 adolescents with a mean age of 12.43 years (SD = 0.65). Mental health problems, such as depressive symptoms, non-suicidal self-injury, suicidal ideation, symptoms of eating disorders, and gender differences, are thoroughly examined. Results revealed a significant portion of our sample displaying mental health problems as early as the 6th and 7th grades, with girls generally being more affected than boys. The findings underscore the importance of early adolescence in the emergence of mental health problems and thereby emphasize the need for preventive measures. Moving beyond prevalence estimates, the compilation delves into the etiology of these disorders, exploring their potential correlation with a COVID-19 infection. Understanding the early signs and risk factors is crucial for timely support. While numerous studies have investigated potential risk and protective factors during the pandemic, our focus shifts to adolescents’ coping when an infection with the virus was involved (N = 2,154, M = 12.31, SD = 0.67). We hypothesized that students infected or with close family members infected, would exhibit an increased psychopathology and a decreased functioning of protective factors such as self-efficacy or self-esteem. We found no connection between infection and the mental health status within our sample, but protective factors and mental well-being were positively associated. Thus, universal primary prevention appears to be the preferred approach for promoting mental health. Lastly, the compilation introduces LessStress, a noteworthy contribution to more evidence-based prevention programs. This universal approach is designed to reduce stress in schools, accompanied by a cluster-randomized trial to evaluate its effectiveness (estimated sample size N = 1,894). Existing studies have demonstrated the effectiveness of stress prevention, leading us to introduce a short and easy-to-implement prevention program. There is positive evidence for one-lesson interventions in schools for promoting well-being and health behaviors among adolescents. LessStress is designed based on a life skills approach that not only imparts psychoeducational content but also teaches skills relevant to everyday life and directly applicable. Throughout these studies, a common thread emerges: the pressing need to address mental disorders during childhood and adolescence. These formative years play a pivotal role in the development of mental health problems. These formative years play a crucial role in the development of mental health problems. They highlight the importance of epidemiological data collection and analysis based on the latest models to develop prevention interventions that are not only effective but also reach young people on a global level.
In February 2017, Braz de Aviz, Prefect of the Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, acknowledged in an interview that some 70 “new spiritual movements” were under investigation for abusive behavior committed by their founders. The number of cases that remain undetected is probably large. This article uses the example of these communities to analyze the precarious tension between vulnerability, vulnerance, and resilience. It draws on Céline Hoyeau's excellent study of those founders of new spiritual movements in France who were later exposed as abusers. It also presents my research on the sacred in its dangerous connection to the victimizing sacrifice. My basic thesis is that exploring the link between vulnerability and resilience is not enough. Rather, vulnerance needs to be systematically included in the analyses. This new approach opens up a more complex understanding of abuse, cover-ups, and disclosure. It can tackle both the vulnerant resilience of the perpetrators and the voluntary vulnerability of survivors in disclosing abuse.
This longitudinal study was performed to evaluate the feasibility of detecting the interaction between wall shear stress (WSS) and plaque development. 20 ApoE\(^{-/-}\)mice were separated in 12 mice with Western Diet and 8 mice with Chow Diet. Magnetic resonance (MR) scans at 17.6 Tesla and histological analysis were performed after one week, eight and twelve weeks. Allin vivoMR measurements were acquired using a flow sensitive phase contrast method for determining vectorial flow. Histological sections were stained with Hematoxylin and Eosin, Elastica van Gieson and CD68 staining. Data analysis was performed using Ensight and a Matlab-based "Flow Tool". The body weight of ApoE\(^{-/-}\)mice increased significantly over 12 weeks. WSS values increased in the Western Diet group over the time period; in contrast, in the Chow Diet group the values decreased from the first to the second measurement point. Western Diet mice showed small plaque formations with elastin fragmentations after 8 weeks and big plaque formations after 12 weeks; Chow Diet mice showed a few elastin fragmentations after 8 weeks and small plaque formations after 12 weeks. Favored by high-fat diet, plaque formation results in higher values of WSS. With wall shear stress being a known predictor for atherosclerotic plaque development, ultra highfield MRI can serve as a tool for studying the causes and beginnings of atherosclerosis.
The wardrobe malfunction—an unanticipated exposure of bodily parts in the public—has become a prevailing issue in concerts, shows and other celebrity events that is reliably reported by the media. The internet as the fastest source for celebrity gossip allows measuring the impact of such wardrobe malfunctions on the public in-terest in a celebrity. This measurement in turn allows conclusions about intention, motivation, and internet be-haviour of a wide variety of internet users. The present study exemplifies the use of an innovative non-reactive measure of active interest—the Search Volume Index—to assess the impact of a variety of internet-related phe-nomena, including wardrobe malfunctions. Results indicate that interest in a celebrity increases immediately af-ter such an event and stays at a high level for about three weeks (the wardrobe plateau). This special form of ce-lebrity gossip thus meets a constant interest of a substantial proportion of internet users.
Climate warming has the potential to disrupt plant-pollinator interactions or to increase competition of co-flowering plants for pollinators, due to species-specific phenological responses to temperature. However, studies focusing on the effect of temperature on solitary bee emergence and the flowering onset of their food plants under natural conditions are still rare. We studied the effect of temperature on the phenology of the two spring bees Osmia cornuta and Osmia bicornis, by placing bee cocoons on eleven grasslands differing in mean site temperature. On seven grasslands, we additionally studied the effect of temperature on the phenology of the red-list plant Pulsatilla vulgaris, which was the first flowering plant, and of co-flowering plants with later flowering. With a warming of 0.1°C, the abundance-weighted mean emergence of O. cornuta males advanced by 0.4 days. Females of both species did not shift their emergence. Warmer temperatures advanced the abundance-weighted mean flowering of P. vulgaris by 1.3 days per 0.1°C increase, but did not shift flowering onset of co-flowering plants. Competition for pollinators between P. vulgaris and co-flowering plants does not increase within the studied temperature range. We demonstrate that temperature advances plant flowering more strongly than bee emergence suggesting an increased risk of pollinator limitation for the first flowers of P. vulgaris.
Summary
Introduction. Rapid and uncontrolled industrialisation and urbanisation in most developing countries are resulting in land, air and water pollution at rates that the natural environment cannot fully renew. These contemporary environmental issues have attracted local, national and international attention. The problem of urban garbage management is associated with rapid population growth in developing countries. These are pertinent environmental crises of sustainability and sanitation in Sub-Saharan Africa and other Third World countries. Despite efforts of the various tiers of government (the case of Nigeria with three tiers: Federal, State and Local governments) in managing solid waste in urban centres, it is still overflowing open dumpsites, litters streets and encroaches into water bodies. These affect the quality of urban living conditions and the natural environment.
Sub-Saharan and other developing countries are experiencing an upsurge in the accumulation and the diversity of waste including E-waste, waste agricultural biomass and waste plastics. The need for effective, sustainable and efficient management of waste through the application of 3Rs principle (Reduce, Reuse, and Recycle) is an essential element for promoting sustainable patterns of consumption and production. This study examined waste management in Imo State, Nigeria as an aspect correlated to the sustainability of its environment.
Materials and methods. To analyse waste management as a correlate of environmental sustainability in Sub-Saharan Africa, Imo State, in eastern Nigeria was chosen as a study area. Issues about waste handling and its impact on the environment in Imo have been reported since its creation in 1976; passing through the State with the cleanest State capital in 1980 to a ‘dunghill’ in 2013 and a ‘garbage capital’ on October 1, 2016. Within this State, three study sites were selected – Owerri metropolis (the State capital) Orlu and Okigwe towns. At these sites, households, commercial areas, accommodation and recreational establishments and schools, as well as dumpsites were investigated to ascertain the composition, quantity, distribution, handling patterns of waste in relation to the sustainability of the State’s environment. This was done conveniently but randomly through questionnaires, interviews, focus group discussions and non-participant observation; these were all heralded by a detailed deskwork. Data were entered using Microsoft Office Excel and were explored and analysed using the Statistical Package for Social Sciences - SPSS.
Data were made essentially of categorical variables and were analysed using descriptive statistics. The association between categorical variables was measured using Cramer’s V the Chi-Square that makes the power and the reliability of the test. Cramer’s V is a measure of association tests directly integrated with cross-tabulation. The Chi-Square test of equal proportions was used to compare proportions for significant differences at 0.05 levels. The statistical package - the Epi Info 6.04d was also used since a contingency table had to be created from several sub-outputs and determine the extent of association between the row and column categories.
The scale variable ‘quantity of waste generated’ was described using measures of central tendency. It was screened for normality using the Kolmogorov-Smirnov and Shapiro-Wilk tests for normality; in all context, the normality assumption was violated (P<0.05). Five null hypotheses were tested using Logistic Regression model. The explanatory power of individual conceptual component was calculated using the Cox & Snell R2 and that of individual indicators was also appraised using the Likelihood Ratio test.
In the context of this work, the significance of the variability explained by the model (baseline model) was appraised using the Omnibus Tests of Model Coefficients, the magnitude of this variability explained by the model using the Cox & Snell R2 and the effects of individual predictors using the Likelihood Ratio test.
Qualitatively, data from open-ended items, observations and interviews were analysed using the process of thematic analysis whereby concepts or ideas were grouped under umbrella terms or keywords. The results were presented using tables, charts, graphs, photos and maps.
Findings and discussions. The total findings and analyses indicated that proper waste handling in Imo State, Nigeria has a positive impact on the environment. This was assessed by the community’s awareness of waste management via sources like the radio and the TV, their education on waste management and schools’ integration of environmental education in their program. Although most community members perceived the State’s environment as compared to it about 10 years’ back has worsened, where they were conscious of proper waste handling measures, the environment was described to be better. This influence of environmental awareness and education on environmental sustainability appraised using Logistic Regression Model, portrayed a significant variability (Omnibus Tests of Model Coefficients: χ2=42.742; P=0.014), inferring that environmental awareness and education significantly predict environmental sustainability.
The findings also revealed that organic waste generation spearheaded amongst other waste types like paper, plastic, E-waste, metal, textile and glass. While waste pickers always sorted paper, plastics, aluminium and metal, some of them also sorted out textile and glass. Statistically (P<0.05), in situations where waste was least generated (i.e., 1-2kg per day), community members maintained that the environmental quality was better in comparison to 10 years’ back. Waste items like broken glass and textile as well as the remains of E-waste after the extraction of copper and brass were not sorted for and these contributed more to environmental degradation.
Similarly, the influence of wealth on environmental sustainability was appraised using Logistic Regression Model including development index related indicators like education, occupation, income and the ability to pay for waste disposal. Harmonising the outcome, farmers, who were mostly the least educated claimed to notice more environmental improvement. In addition, those who did not agree to pay for waste disposal who were mostly those with low income (less than 200,000 Naira, i.e. about 620 Euros monthly) perceived environmental improvement more than those with income above 200,000 Naira. This irony can be attributed to the fact that those with low educational backing lack the capacity to appreciate environmental sustainability pointers well as compared to those with a broader educational background with critical thinking.
The employment and poverty reduction opportunities pertaining to waste management on environmental sustainability was appraised using qualitative thematic analysis. All community members involved in sorting, buying and selling of waste items had no second job. They attested that the money earned from their activities sustained their livelihood and families. Some expressed love for the job, especially as they were their own masters. Waste picking and trading in waste items are offering employment opportunities to many communities around the world. For instance, in the waste recycling, waste composting, waste-to-energy plants and die Stadtreiniger in Würzburg city. The workers in these enterprises have jobs as a result of waste.
Waste disposal influence on environmental sustainability was appraised using the Binary Logistic Regression Model and the variability explained by the model was significant. The validity was also supported by the Wald statistics (P<0.05), which indicates the effect of the predictors is significant. Environmental sustainability was greatly reliant on indicators like the frequency at which community members emptied their waste containers; how/where waste is disposed of, availability of disposal site or public bin near the house, etc. Imolites who asserted to have public waste bins or disposal sites near their houses maintained that the quality of the State’s environment had worsened as such containers/disposal sites were always stinking as well as had animals and smoke around them. Imolites around disposal sites complained of traits like diarrhoea, catarrh, insect bites, malaria, smoke and polluted air.
Conclusions. The liaison between poor waste management strategies and the sustainability of the Imo State environment was considered likely as statistically significant ineffectiveness, lack of awareness, poverty, insufficient and unrealistic waste management measures were found in this study area. In these situations, the environment was said to have not improved. Such inadequacies in the handling of generated waste did not only expose the citizenry to health dangers but also gave rise to streets and roads characterized by filth and many unattended disposal sites unleashing horrible odour to the environment and attracting wild animals. This situation is not only prevalent in Imo State, Nigeria but in many Sub-Saharan cities.
Future Perspectives. To improve the environment in Sub-Saharan Africa, it is imperative to practice an inclusive and integrated sustainable waste management system. The waste quantity in this region is fast growing, especially food/organic waste. The region should aim at waste management laws and waste reduction strategies, which will help save and produce more food that it really needs. Waste management should be dissociated from epidemic outbreaks like cholera, typhoid, Lassa fever and malaria, whose vectors thrive in filthy environments. Water channels and water bodies should not be waste disposal channels or waste disposal sites.
Previous research showed that priming effects in the affective misattribution procedure (AMP) are unaffected by direct warnings to avoid an influence of the primes. The present research examined whether a priming influence is diminished by task procedures that encourage accurate judgments of the targets. Participants were motivated to categorize the affective meaning of nonsense targets accurately by being made to believe that a true word was presented in each trial and by providing feedback on (allegedly) incorrect responses. This condition produced robust priming effects. Priming was however reduced and less reliable relative to more typical AMP conditions in which participants guessed the meaning of openly presented nonsense targets. Affective judgments of nonsense targets were not affected by advance knowledge of the response mapping during the priming phase, which argues against a response-priming explanation of AMP effects. These findings show that affective primes influence evaluative judgments even in conditions in which the motivation to provide accurate responses is high and a priming of motor responses is not possible. Priming effects were however weaker with high accuracy motivation, suggesting that a focus on accurate judgments is an effective strategy to control for an unwanted priming influence in the AMP.
Farmland tree cultivation is considered an important option for enhancing wood production. In South India, the native leaf-deciduous tree species Melia dubia is popular for short-rotation plantations. Across a rainfall gradient from 420 to 2170 mm year\(^{–1}\), we studied 186 farmland woodlots between one and nine years in age. The objectives were to identify the main factors controlling aboveground biomass (AGB) and growth rates. A power-law growth model predicts an average stand-level AGB of 93.8 Mg ha\(^{–1}\) for nine-year-old woodlots. The resulting average annual AGB increment over the length of the rotation cycle is 10.4 Mg ha\(^{–1}\) year\(^{–1}\), which falls within the range reported for other tropical tree plantations. When expressing the parameters of the growth model as functions of management, climate and soil variables, it explains 65% of the variance in AGB. The results indicate that water availability is the main driver of the growth of M. dubia. Compared to the effects of water availability, the effects of soil nutrients are 26% to 60% smaller. We conclude that because of its high biomass accumulation rates in farm forestry, M. dubia is a promising candidate for short-rotation plantations in South India and beyond.