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When More Is Better – Consumption Priming Decreases Responders’ Rejections in the Ultimatum Game
(2017)
During the past decades, economic theories of rational choice have been exposed to outcomes that were severe challenges to their claim of universal validity. For example, traditional theories cannot account for refusals to cooperate if cooperation would result in higher payoffs. A prominent illustration are responders’ rejections of positive but unequal payoffs in the Ultimatum Game. To accommodate this anomaly in a rational framework one needs to assume both a preference for higher payoffs and a preference for equal payoffs. The current set of studies shows that the relative weight of these preference components depends on external conditions and that consumption priming may decrease responders’ rejections of unequal payoffs. Specifically, we demonstrate that increasing the accessibility of consumption-related information accentuates the preference for higher payoffs. Furthermore, consumption priming increased responders’ reaction times for unequal payoffs which suggests an increased conflict between both preference components. While these results may also be integrated into existing social preference models, we try to identify some basic psychological processes underlying economic decision making. Going beyond the Ultimatum Game, we propose that a distinction between comparative and deductive evaluations may provide a more general framework to account for various anomalies in behavioral economics.
Context: Patients with primary adrenal insufficiency (PAI) or congenital adrenal hyperplasia (CAH) are at a high risk of adrenal crisis (AC). Glucocorticoid sensitivity is at least partially genetically determined by polymorphisms of the glucocorticoid receptor (GR).
Objectives: To determine if a number of intercurrent illnesses and AC are associated with the GR gene polymorphism \(Bcl\)I in patients with PAI and CAH.
Design and patients: This prospective, longitudinal study over 37.7 ± 10.1 months included 47 PAI and 25 CAH patients. During the study period, intercurrent illness episodes and AC were documented.
Results: The study period covered 223 patient years in which 21 AC occurred (9.4 AC/100 pat years). There were no significant differences between \(Bcl\)I polymorphisms (CC (n=29), CG (n=34) and GG (n=9)) regarding BMI, hydrocortisone equivalent daily dose and blood pressure. We did not find a difference in the number of intercurrent illnesses/patient year among \(Bcl\)I polymorphisms (CC (1.5±1.4/pat year), CG (1.2±1.2/pat year) and GG (1.6±2.2/pat year)). The occurrence of AC was not significantly different among the homozygous (GG) genotype (32.5 AC/100 pat years), the CC genotype (6.7 AC/100 pat years) and the CG genotype (4.9 AC/100 pat years). Concomitant hypothyroidism was the highest in the GG genotype group (5/9), compared to others (CC (11/29) and CG (11/34)).
Conclusions: Although sample sizes were relatively small and results should be interpreted with caution, this study suggests that the GR gene polymorphism \(Bcl\)I may not be associated with the frequencies of intercurrent illnesses and AC.
Purpose: Research dealing with ischemic preconditioning (IPC) has primarily focused on variables associated to endurance performance with little research about the acute responses of IPC on repeated multidirectional running sprint performance. Here we aimed to investigate the effects of IPC of the arms and the legs on repeated running sprint performance with changes-of-direction (COD) movements.
Methods: Thirteen moderately-to-well-trained team-sport athletes (7 males; 6 females; age: 24 ± 2 years, size: 175 ± 8 cm, body mass: 67.9 ± 8.1 kg) performed 16 × 30 m all-out sprints (15 s rest) with multidirectional COD movements on a Speedcourt\(^{©}\) with IPC (3 × 5 min) of the legs (IPC\(_{leg}\); 240 mm Hg) or of the arms (remote IPC: IPC\(_{remote}\); 180–190 mm Hg) 45 min before the sprints and a control trial (CON; 20 mm Hg).
Results: The mean (±SD) time for the 16 × 30 m multidirectional COD sprints was similar between IPC\(_{leg}\) (Mean t: 16.0 ± 1.8 s), IPC\(_{remote}\) (16.2 ± 1.7 s), and CON (16.0 ± 1.6 s; p = 0.50). No statistical differences in oxygen uptake (mean difference: 0%), heart rate (1.1%) nor muscle oxygen saturation of the vastus lateralis (4.7%) and biceps brachii (7.8%) between the three conditions were evident (all p > 0.05).
Conclusions: IPC (3 × 5 min) of the legs (220 mm Hg) or arms (180–190 mm Hg; remote IPC) applied 45 min before 16 × 30 m repeated multidirectional running sprint exercise does not improve sprint performance, oxygen uptake, heart rate nor muscle oxygen saturation of the vastus lateralis muscle when compared to a control trial.
For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.
Background:
Clinical reasoning in Neurology is based on general associations which help to deduce the site of the lesion. However, even “golden principles” may occasionally be deceptive. Here, we describe the case of subacute flaccid tetraparesis due to motor cortical lesions. To our knowledge, this is the first report to include an impressive illustration of nearly symmetric motor cortical involvement of encephalitis on brain MRI.
Case presentation:
A 51 year old immunocompromized man developed a high-grade pure motor flaccid tetraparesis over few days. Based on clinical presentation, critical illness polyneuromyopathy was suspected. However, brain MRI revealed symmetrical hyperintensities strictly limited to the subcortical precentral gyrus. An encephalitis, possibly due to CMV infection, turned out to be the most likely cause.
Conclusion:
While recognition of basic clinical patterns is indispensable in neurological reasoning, awareness of central conditions mimicking peripheral nervous disease may be crucial to detect unsuspected, potentially treatable conditions.
Background:
Sleep-related eating may occur in the context of mental illness, sleep disorders, or psychopharmacological treatment. Frequently, sleep-related eating leads to severe weight gain and, so far, there are no treatment options for the condition.
Case presentation:
We report the case of a 54-year-old white woman with depression, panic disorder, and sleep apnea under treatment with various antidepressants who developed severe sleep-related eating. Her sleep-related eating completely vanished after addition of agomelatine, it reoccurred after cessation of agomelatine, and vanished again after her re-exposure to another melatonergic drug, extended melatonin.
Conclusions:
This case suggests that melatonergic drugs lead to relief from sleep-related eating, even when the condition occurs in the context of physical and mental disorders as well as psychopharmacological treatment.
The importance of enterprise systems is increasingly growing and they are in the center of attention and consideration by organizations in various types of business and industries from extra-large public or private organizations to small and medium-sized service sector business. These systems are continuously advancing functionally and technologically and are inevitable and ineluctable for the enterprises to maximize their productivity and integration in current competitive national and global business environments.
Also, since local software solutions could not meet the requirements of especially large enterprises functionally and technically, and as giant global enterprise software producers like SAP, Oracle and Microsoft are improving their solutions rapidly and since they are expanding their market to more corners of the globe, demand for these globally branded low-defect software solutions is daily ascending. The agreements for international ERP implementation project consultancy are, therefore, exponentially increasing, while the research on the influencing factors and know-hows is scattered and rare, and thus, a timely urgency for this field of research is being felt.
The final developed five-in-five framework of this study, for the first time, collects all mentioned-in-the-history critical success factors and project activities, while sequencing them in five phases and categorizing them in five focus areas for international ERP implementation projects. This framework provides a bird’s-eye view and draws a comprehensive roadmap or instruction for such projects.
Anionic Adducts
Sp2-sp3 tetraalkoxy diboron compounds have gained attention due to the development of new, synthetically useful catalytic reactions either with or without transition-metals. Lewis-base adducts of the diboron(4) compounds were suggested as possible intermediates in Cu catalyzed borylation reactions some time ago. However, intermolecular adducts of tetraalkoxy diboron compounds have not been studied yet in great detail. In preliminary studies, we have synthesized a series of anionic sp2-sp3 adducts of B2pin2 with alkoxy-groups (L = [OMe]–, [OtBu]–), a phenoxy-group (L = [4-tBuC6H4O]–) and fluoride (L = [F]–, with [nBu4N]+ as the counter ion) as Lewis-bases.
Neutral Adducts
Since their isolation and characterization, applications of N-heterocyclic carbenes (NHCs) and related molecules, e.g., cyclic alkylaminocarbenes (CAACs) and acyclic diaminocarbenes (aDCs), have grown rapidly. Their use as ligands in homogeneous catalysis and directly in organocatalysis, including recently developed borylation reactions, is now well established. Recently, several examples of ring expansion reactions (RER) involving NHCs were reported to take place at elevated temperatures, involving Be, B, and Si.
Furthermore, preliminary studies in the group of Marder et al. showed the presence of neutral sp2-sp3 diboron compounds with B2pin2 and the NHC Cy2Im. In this work, we focused on the synthesis and characterization of further neutral sp2-sp3 as well as sp3-sp3 diboron adducts with B2cat2 and B2neop2 and different NHCs. Whereas the mono-NHC adduct is stable for several hours at temperatures up to 60 °C, the bis-NHC adducts undergo thermally induced rearrangement to form the ring expanded products compound 26 and 27. B2neop2 is much more reactive than B2cat2 giving ring expanded product 29 at room temperature in quantitative yields, demonstrating that NHC ring expansion and B–B bond cleavage can be very facile processes.
Whereas the mono-NHC adduct is stable for several hours at temperatures up to 60 °C, the bis-NHC adducts undergo thermally induced rearrangement to form the ring expanded products compound 26 and 27. B2neop2 is much more reactive than B2cat2 giving ring expanded product 29 at room temperature in quantitative yields, demonstrating that NHC ring expansion and B–B bond cleavage can be very facile processes.
Background
Herpesviruses can infect a wide range of animal species. Herpes simplex virus 1 (HSV-1) is one of the eight herpesviruses that can infect humans and is prevalent worldwide. Herpesviruses have evolved multiple ways to adapt the infected cells to their needs, but knowledge about these transcriptional and post-transcriptional modifications is sparse.
Results
Here, we show that HSV-1 induces the expression of about 1000 antisense transcripts from the human host cell genome. A subset of these is also activated by the closely related varicella zoster virus. Antisense transcripts originate either at gene promoters or within the gene body, and they show different susceptibility to the inhibition of early and immediate early viral gene expression. Overexpression of the major viral transcription factor ICP4 is sufficient to turn on a subset of antisense transcripts. Histone marks around transcription start sites of HSV-1-induced and constitutively transcribed antisense transcripts are highly similar, indicating that the genetic loci are already poised to transcribe these novel RNAs. Furthermore, an antisense transcript overlapping with the BBC3 gene (also known as PUMA) transcriptionally silences this potent inducer of apoptosis in cis.
Conclusions
We show for the first time that a virus induces widespread antisense transcription of the host cell genome. We provide evidence that HSV-1 uses this to downregulate a strong inducer of apoptosis. Our findings open new perspectives on global and specific alterations of host cell transcription by viruses.
Strong light matter coupling between excitons and microcavity photons, as described in the framework of cavity quantum electrodynamics, leads to the hybridization of light and matter excitations. The regime of collective strong coupling arises, when various excitations from different host media are strongly coupled to the same optical resonance. This leads to a well-controllable admixture of various matter components in three hybrid polariton modes. Here, we study a cavity device with four embedded GaAs quantum wells hosting excitons that are spectrally matched to the A-valley exciton resonance of a MoSe\(_{2}\) monolayer. The formation of hybrid polariton modes is evidenced in momentum resolved photoluminescence and reflectivity studies. We describe the energy and k-vector distribution of exciton-polaritons along the hybrid modes by a thermodynamic model, which yields a very good agreement with the experiment.
Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identifed the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efciently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.
The MuvB multiprotein complex, together with B-MYB and FOXM1 (MMB-FOXM1), plays an essential role in cell cycle progression by regulating the transcription of genes required for mitosis and cytokinesis. In many tumors, B-MYB and FOXM1 are overexpressed as part of the proliferation signature. However, the transcriptional targets that are important for oncogenesis have not been identified. Given that mitotic kinesins are highly expressed in cancer cells and that selected kinesins have been reported as target genes of MMB-FOXM1, we sought to determine which mitotic kinesins are directly regulated by MMB-FOXM1. We demonstrate that six mitotic kinesins and two microtubule-associated non-motor proteins (MAPs) CEP55 and PRC1 are direct transcriptional targets of MuvB, B-MYB and FOXM1 in breast cancer cells.
Suppression of KIF23 and PRC1 strongly suppressed proliferation of MDA-MB-231 cells. The set of MMB-FOXM1 regulated kinesins genes and 4 additional kinesins which we referred to as the mitotic kinesin signature (MKS) is linked to poor outcome in breast cancer patients. Thus, mitotic kinesins could be used as prognostic biomarker and could be potential therapeutic targets for the treatment of breast cancer.
The field of genetics faces a lot of challenges and opportunities in both research and diagnostics due to the rise of next generation sequencing (NGS), a technology that allows to sequence DNA increasingly fast and cheap.
NGS is not only used to analyze DNA, but also RNA, which is a very similar molecule also present in the cell, in both cases producing large amounts of data.
The big amount of data raises both infrastructure and usability problems, as powerful computing infrastructures are required and there are many manual steps in the data analysis which are complicated to execute.
Both of those problems limit the use of NGS in the clinic and research, by producing a bottleneck both computationally and in terms of manpower, as for many analyses geneticists lack the required computing skills.
Over the course of this thesis we investigated how computer science can help to improve this situation to reduce the complexity of this type of analysis.
We looked at how to make the analysis more accessible to increase the number of people that can perform OMICS data analysis (OMICS groups various genomics data-sources).
To approach this problem, we developed a graphical NGS data analysis pipeline aimed at a diagnostics environment while still being useful in research in close collaboration with the Human Genetics Department at the University of Würzburg.
The pipeline has been used in various research papers on covering subjects, including works with direct author participation in genomics, transcriptomics as well as epigenomics.
To further validate the graphical pipeline, a user survey was carried out which confirmed that it lowers the complexity of OMICS data analysis.
We also studied how the data analysis can be improved in terms of computing infrastructure by improving the performance of certain analysis steps.
We did this both in terms of speed improvements on a single computer (with notably variant calling being faster by up to 18 times), as well as with distributed computing to better use an existing infrastructure.
The improvements were integrated into the previously described graphical pipeline, which itself also was focused on low resource usage.
As a major contribution and to help with future development of parallel and distributed applications, for the usage in genetics or otherwise, we also looked at how to make it easier to develop such applications.
Based on the parallel object programming model (POP), we created a Java language extension called POP-Java, which allows for easy and transparent distribution of objects.
Through this development, we brought the POP model to the cloud, Hadoop clusters and present a new collaborative distributed computing model called FriendComputing.
The advances made in the different domains of this thesis have been published in various works specified in this document.
Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties.
Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties.
Irritable bowel syndrome (IBS) is a gut-brain disorder involving alterations in intestinal sensitivity and motility. Serotonin 5-HT4 receptors are promising candidates in IBS pathophysiology since they regulate gut motor function and stool consistency, and targeted 5-HT4R selective drug intervention has been proven beneficial in subgroups of patients. We identified a single nucleotide polymorphism (SNP) (rs201253747) c.*61 T > C within the 5-HT4 receptor gene \(HTR4\) to be predominantly present in diarrhoea-IBS patients (IBS-D). It affects a binding site for the miR-16 family and miR-103/miR-107 within the isoforms \({HTR4b/i}\) and putatively impairs \(HTR4\) expression. Subsequent miRNA profiling revealed downregulation of miR-16 and miR-103 in the jejunum of IBS-D patients correlating with symptoms. \(In\) \(vitro\) assays confirmed expression regulation via three 3′UTR binding sites. The novel isoform \(HTR4b\_2\) lacking two of the three miRNA binding sites escapes miR-16/103/107 regulationin SNP carriers. We provide the first evidence that \(HTR4\) expression is fine-tuned by miRNAs, and that this regulation is impaired either by the SNP c.*61 T > C or bydiminished levels of miR-16 and miR-103 suggesting that \(HTR4\) might be involved in the development of IBS-D.
Social life is organized around rules and norms. The present experiments investigate the cognitive architecture of rule violations. To do so, a setting with arbitrary rules that had to be followed or broken was developed, and breaking these rules did not have any negative consequences. Removed from any social influences that might further encourage or hinder the rule breaker, results suggest that simply labeling a behavior as a rule violation comes with specific costs: They are more difficult to plan and come with specific behavioral markers during execution. In essence, rule violations resemble rule negations, but they also trigger additional processes.
The question of what makes rule violations more difficult than rule inversions is the major focus of the remaining experiments. These experiments revealed negative affective consequences of rule violation and rule inversions alike, while rule violations additionally prime authority-related concepts, thus sensitizing towards authority related stimuli.
Next, the question how these burdens of non-conformity can be mitigated was investigated, and the influence of having executed the behavior in question frequently and recently was tested in both negations and rule violations. The burdens of non-conformity can best be reduced by a combination of having violated/negated a rule very frequently and very recently. Transfer from another task, however, could not be identified.
To conclude, a model that accounts for the data that is currently presented is proposed. As a variant of a task switching model, it describes the cognitive processes that were investigated and highlights unique processing steps that rule violations seem to require.
Driving simulators are powerful research tools. Countless simulator studies have contributed to traffic safety over the last decades. Constant improvements in simulator technology call for a measureable scale to assess driving simulators with regard to their utility in human factors research. A promising psychological construct to do so is presence. It is commonly defined as the feeling of being located in a remote or virtual environment that seems to be real. Another aspect of presence describes the ability to act there successfully.
The main aim of this thesis is to develop a presence model dedicated to the application in driving simulators. Established models have been combined and extended in order to gain a comprehensive model of presence that allows understanding its emergence and deriving recommendations on how to design or improve driving simulators. The five studies presented in this thesis investigate specific postulated model components and their interactions. All studies deal with motorcycling or a motorcycle riding simulator as exemplary field of application.
The first study used a speed estimation task to investigate the contribution of different sensory cues to presence. While visualization plays a particularly important role, further improvements could be achieved by adding more consistent sensory stimuli to the virtual environment. Auditory, proprioceptive and vestibular cues have been subject to investigation. In the second study, the speed production method was applied. It confirmed the positive contribution of action to presence as predicted by psychocybernetic models. The third study dealt with the effect of training on presence. Hence, no positive effect was observed. The fourth study aimed at replicating previous findings on sensory fidelity and diversity in a more complex riding situation than only longitudinal vehicle control. The riders had to cross an unexpectedly appearing deep pit with the virtual motorcycle. The contribution of more consistent sensory stimulation on presence was successfully shown in this scenario, too. The final study was a real riding experiment that delivered reference values for the speed estimation capabilities of motorcycle riders. Besides higher variations in the simulator data, the general speed estimation performance was on a comparable level. Different measures, such as subjective ratings, behavioral responses, performance, and physiological reactions, have been applied as presence indicators.
These studies’ findings deliver evidence for the meaningful application of the proposed presence model in driving simulator settings. The results suggest that presence can be interpreted as a quality measure for perception in virtual environments. In line with psychocybernetic models, taking action, which is seen as controlling perception, enhances this quality even further. Describing the psychological construct of presence in a theoretical framework that takes the diversity of perception and action in driving simulator settings into account closes a gap in traffic psychological research.
Background
40–50% of patients with colorectal cancer (CRC) will develop liver metastases (CRLM) during the course of the disease. One third of these patients will additionally develop pulmonary metastases.
Methods
137 consecutive patients with CRLM, were analyzed regarding survival data, clinical, histological data and treatment. Results were stratified according to the occurrence of pulmonary metastases and metastases resection.
Results
39% of all patients with liver resection due to CRLM developed additional lung metastases. 44% of these patients underwent subsequent pulmonary resection. Patients undergoing pulmonary metastasectomy showed a significantly better five-year survival compared to patients not qualified for curative resection (5-year survival 71.2% vs. 28.0%; p = 0.001). Interestingly, the 5-year survival of these patients was even superior to all patients with CRLM, who did not develop pulmonary metastases (77.5% vs. 63.5%; p = 0.015). Patients, whose pulmonary metastases were not resected, were more likely to redevelop liver metastases (50.0% vs 78.6%; p = 0.034). However, the rate of distant metastases did not differ between both groups (54.5 vs.53.6; p = 0.945).
Conclusion
The occurrence of colorectal lung metastases after curative liver resection does not impact patient survival if pulmonary metastasectomy is feasible. Those patients clearly benefit from repeated resections of the liver and the lung metastases.
Colorectal carcinoma (CRC) is the most common cancer of the gastrointestinal tract with frequently dysregulated intracellular signaling pathways, including p53 signaling. The mainstay of chemotherapy treatment of CRC is 5-fluorouracil (5FU) and oxaliplatin. The two anticancer drugs mediate their therapeutic effect via DNA damage-triggered signaling. The small molecule reactivating p53 and inducing tumor apoptosis (RITA) is described as an activator of wild-type and reactivator of mutant p53 function, resulting in elevated levels of p53 protein, cell growth arrest, and cell death. Additionally, it has been shown that RITA can induce DNA damage signaling. It is expected that the therapeutic benefits of 5FU and oxaliplatin can be increased by enhancing DNA damage signaling pathways. Therefore, we highlighted the antiproliferative response of RITA alone and in combination with 5FU or oxaliplatin in human CRC cells. A panel of long-term established CRC cell lines (n = 9) including p53 wild-type, p53 mutant, and p53 null and primary patient-derived, low-passage cell lines (n = 5) with different p53 protein status were used for this study. A substantial number of CRC cells with pronounced sensitivity to RITA (IC\(_{50}\)< 3.0 μmol/l) were identified within established (4/9) and primary patient-derived (2/5) CRC cell lines harboring wild-type or mutant p53 protein. Sensitivity to RITA appeared independent of p53 status and was associated with an increase in antiproliferative response to 5FU and oxaliplatin, a transcriptional increase of p53 targets p21 and NOXA, and a decrease in MYC mRNA. The effect of RITA as an inducer of DNA damage was shown by a strong elevation of phosphorylated histone variant H2A.X, which was restricted to RITA-sensitive cells. Our data underline the primary effect of RITA, inducing DNA damage, and demonstrate the differential antiproliferative effect of RITA to CRC cells independent of p53 protein status. We found a substantial number of RITA-sensitive CRC cells within both panels of established CRC cell lines and primary patient-derived CRC cell lines (6/14) that provide a rationale for combining RITA with 5FU or oxaliplatin to enhance the antiproliferative response to both chemotherapeutic agents.
The transcriptome is a powerful proxy for the physiological state of a cell, healthy or diseased. As a result, transcriptome analysis has become a key tool in understanding the molecular changes that accompany bacterial infections of eukaryotic cells. Until recently, such transcriptomic studies have been technically limited to analyzing mRNA expression changes in either the bacterial pathogen or the infected eukaryotic host cell. However, the increasing sensitivity of high-throughput RNA sequencing now enables “dual RNA-seq” studies, simultaneously capturing all classes of coding and noncoding transcripts in both the pathogen and the host. In the five years since the concept of dual RNA-seq was introduced, the technique has been applied to a range of infection models. This has not only led to a better understanding of the physiological changes in pathogen and host during the course of an infection but has also revealed hidden molecular phenotypes of virulence-associated small noncoding RNAs that were not visible in standard infection assays. Here, we use the knowledge gained from these recent studies to suggest experimental and computational guidelines for the design of future dual RNA-seq studies. We conclude this review by discussing prospective applications of the technique.
Introduction: The prognosis of medullary thyroid carcinoma (MTC) is poor using common chemotherapeutic approaches. However, during the last years encouraging results of recently introduced tyrosine kinase inhibitors (TKI) such as vandetanib have been published. In this study we aimed to correlate the results of \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG) positron emission tomography (PET) imaging with treatment outcome.
Methods: Eighteen patients after thyroidectomy with recurrent/advanced MTC lesions receiving vandetanib (300 mg orally/day) could be analysed. A baseline \(^{18}\)F-FDG PET prior to and a follow-up \(^{18}\)F-FDG PET 3 months after TKI initiation were performed. During follow-up, tumor progression was assessed every 3 months including computed tomography according to RECIST. Progression-free survival (PFS) was correlated with the maximum standardized uptake value of \(^{18}\)F-FDG in lymph nodes (SUV(LN)max) or visceral metastases (SUV(MTS)max) as well as with clinical parameters using ROC analysis.
Results: Within median 3.6 years of follow-up, 9 patients showed disease progression at median 8.5 months after TKI initiation. An elevated glucose consumption assessed by baseline \(^{18}\)F-FDG PET (SUV(LN)max > 7.25) could predict a shorter PFS (2 y) with an accuracy of 76.5% (SUV(LN)max <7.25, 4.3 y; p=0.03). Accordingly, preserved tumor metabolism in the follow-up PET (SUV(MTS)max >2.7) also demonstrated an unfavorable prognosis (accuracy, 85.7%). On the other hand, none of the clinical parameters reached significance in response prediction.
Conclusions: In patients with advanced and progressive MTC, tumors with higher metabolic activity at baseline are more aggressive and more prone to progression as reflected by a shorter PFS; they should be monitored more closely. Preserved glucose consumption 3 months after treatment initiation was also related to poorer prognosis.
C-X-C motif chemokine receptor 4 (CXCR4) and somatostatin receptors (SSTR) are overexpressed in gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In this study, we aimed to elucidate the feasibility of non-invasive CXCR4 positron emission tomography/computed tomography (PET/CT) imaging in GEP-NET patients using [\(^{68}\)Ga]Pentixafor in comparison to \(^{68}\)Ga-DOTA-D-Phe-Tyr3-octreotide ([\(^{68}\)Ga]DOTATOC) and \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG). Twelve patients with histologically proven GEP-NET (3xG1, 4xG2, 5xG3) underwent [\(^{68}\)Ga]DOTATOC, [\(^{18}\)F]FDG, and [\(^{68}\)Ga]Pentixafor PET/CT for staging and planning of the therapeutic management. Scans were analyzed on a patient as well as on a lesion basis and compared to immunohistochemical staining patterns of CXCR4 and somatostatin receptors SSTR2a and SSTR5. [\(^{68}\)Ga]Pentixafor visualized tumor lesions in 6/12 subjects, whereas [\(^{18}\)F]FDG revealed sites of disease in 10/12 and [\(^{68}\)Ga]DOTATOC in 11/12 patients, respectively. Regarding sensitivity, SSTR-directed PET was the superior imaging modality in all G1 and G2 NET. CXCR4-directed PET was negative in all G1 NET. In contrast, 50% of G2 and 80% of G3 patients exhibited [\(^{68}\)Ga]Pentixafor-positive tumor lesions. Whereas CXCR4 seems to play only a limited role in detecting well-differentiated NET, increasing receptor expression could be non-invasively observed with increasing tumor grade. Thus, [\(^{68}\)Ga]Pentixafor PET/CT might serve as non-invasive read-out for evaluating the possibility of CXCR4-directed endoradiotherapy in advanced dedifferentiated SSTR-negative tumors.
Objective: Radiotracers targeting prostate-specific membrane antigen (PSMA) have increasingly been recognized as showing uptake in a number of normal structures, anatomic variants, and non-prostate-cancer pathologies. We aimed to explore the frequency and degree of uptake in peripheral ganglia in patients undergoing PET with the PSMA-targeted agent \(^{18}\)F-DCFPyL.
Methods: A total of 98 patients who underwent \(^{18}\)F-DCFPyL PET/CT imaging were retrospectively analyzed. This included 76 men with prostate cancer (PCa) and 22 patients with renal cell carcinoma (RCC; 13 men, 9 women). Scans were evaluated for uptake in the cervical, stellate, celiac, lumbar and sacral ganglia. Maximum standardized uptake value corrected to body weight (SUV\(_{max}\)), and maximum standardized uptake value corrected to lean body mass (SUL\(_{max}\)) were recorded for all ganglia with visible uptake above background. Ganglia-to-background ratios were calculated by dividing the SUV\(_{max}\) and SUL\(_{max}\) values by the mean uptake in the ascending aorta (Aortamean) and the right gluteus muscle (Gluteusmean).
Results: Overall, 95 of 98 (96.9%) patients demonstrated uptake in at least one of the evaluated peripheral ganglia. With regard to the PCa cohort, the most frequent sites of radiotracer accumulation were lumbar ganglia (55/76, 72.4%), followed by the cervical ganglia (51/76, 67.1%). Bilateral uptake was found in the majority of cases [lumbar 44/55 (80%) and cervical 30/51 (58.8%)]. Additionally, discernible radiotracer uptake was recorded in 50/76 (65.8%) of the analyzed stellate ganglia and in 45/76 (59.2%) of the celiac ganglia, whereas only 5/76 (6.6%) of the sacral ganglia demonstrated \(^{18}\)F-DCFPyL accumulation. Similar findings were observed for patients with RCC, with the most frequent locations of radiotracer uptake in both the lumbar (20/22, 90.9%) and cervical ganglia (19/ 22, 86.4%). No laterality preference was found in mean PSMA-ligand uptake for either the PCa or RCC cohorts.
Conclusion: As PSMA-targeted agents become more widely disseminated, the patterns of uptake in structures that are not directly relevant to patients’ cancers must be understood. This is the first systematic evaluation of the uptake of \(^{18}\)F-DCFPyL in ganglia demonstrating a general trend with a descending frequency of radiotracer accumulation in lumbar, cervical, stellate, celiac, and sacral ganglia. The underlying biology that leads to variability of PSMA-targeted radiotracers in peripheral ganglia is not currently understood, but may provide opportunities for future research.
Plants have to tightly control their energy homeostasis to ensure survival and fitness under constantly changing environmental conditions. Thus, it is stringently required that energy-consuming stress-adaptation and growth-related processes are dynamically tuned according to the prevailing energy availability. The evolutionary conserved SUCROSE NON-FERMENTING1 RELATED KINASES1 (SnRK1) and the downstream group C/S\(_{1}\) basic leucine zipper (bZIP) transcription factors (TFs) are well-characterised central players in plants’ low-energy management. Nevertheless, mechanistic insights into plant growth control under energy deprived conditions remains largely elusive. In this work, we disclose the novel function of the low-energy activated group S\(_{1}\) bZIP11-related TFs as regulators of auxin-mediated primary root growth. Whereas transgenic gain-of-function approaches of these bZIPs interfere with the activity of the root apical meristem and result in root growth repression, root growth of loss-of-function plants show a pronounced insensitivity to low-energy conditions. Based on ensuing molecular and biochemical analyses, we propose a mechanistic model, in which bZIP11-related TFs gain control over the root meristem by directly activating IAA3/SHY2 transcription. IAA3/SHY2 is a pivotal negative regulator of root growth, which has been demonstrated to efficiently repress transcription of major auxin transport facilitators of the PIN-FORMED (PIN) gene family, thereby restricting polar auxin transport to the root tip and in consequence auxin-driven primary root growth. Taken together, our results disclose the central low-energy activated SnRK1-C/S\(_{1}\)-bZIP signalling module as gateway to integrate information on the plant’s energy status into root meristem control, thereby balancing plant growth and cellular energy resources.
Somatic mutations in protein kinase A catalytic α subunit (PRKACA) were found to be causative for 30-40% of cortisol-producing adenomas (CPA) of the adrenal gland, rendering PKA signalling constitutively active. In its resting state, PKA is a stable and inactive heterotetramer, consisting of two catalytic and two regulatory subunits with the latter inhibiting PKA activity. The human genome encodes three different PKA catalytic subunits and four different regulatory subunits that are preferentially expressed in different organs. In normal adrenal glands all regulatory subunits are expressed, while CPA exhibit reduced protein levels of the regulatory subunit IIβ. In this study, we linked for the first time the loss of RIIβ protein levels to the PRKACA mutation status and found the down-regulation of RIIβ to arise post-transcriptionally. We further found the PKA subunit expression pattern of different tumours is also present in the zones of the normal adrenal cortex and demonstrate that the different PKA subunits have a differential expression pattern in each zone of the normal adrenal gland, indicating potential specific roles of these subunits in the regulation of different hormones secretion.
TP53 mutations have been associated with anaplasia in Wilms tumour, which conveys a high risk for relapse and fatal outcome. Nevertheless, TP53 alterations have been reported in no more than 60% of anaplastic tumours, and recent data have suggested their presence in tumours that do not fulfil the criteria for anaplasia, questioning the clinical utility of TP53 analysis. Therefore, we characterized the TP53 status in 84 fatal cases of Wilms tumour, irrespective of histological subtype. We identified TP53 alterations in at least 90% of fatal cases of anaplastic Wilms tumour, and even more when diffuse anaplasia was present, indicating a very strong if not absolute coupling between anaplasia and deregulation of p53 function. Unfortunately, TP53 mutations do not provide additional predictive value in anaplastic tumours since the same mutation rate was found in a cohort of non-fatal anaplastic tumours. When classified according to tumour stage, patients with stage I diffuse anaplastic tumours still had a high chance of survival (87%), but this rate dropped to 26% for stages II–IV. Thus, volume of anaplasia or possible spread may turn out to be critical parameters. Importantly, among non-anaplastic fatal tumours, 26% had TP53 alterations, indicating that TP53 screening may identify additional cases at risk. Several of these non-anaplastic tumours fulfilled some criteria for anaplasia, for example nuclear unrest, suggesting that such partial phenotypes should be under special scrutiny to enhance detection of high-risk tumours via TP53 screening. A major drawback is that these alterations are secondary changes that occur only later in tumour development, leading to striking intratumour heterogeneity that requires multiple biopsies and analysis guided by histological criteria. In conclusion, we found a very close correlation between histological signs of anaplasia and TP53 alterations. The latter may precede development of anaplasia and thereby provide diagnostic value pointing towards aggressive disease.
The regulation of replication is essential to preserve genome integrity. Mms1 is part of the E3 ubiquitin ligase complex that is linked to replication fork progression. By identifying Mms1 binding sites genome-wide in Saccharomyces cerevisiae we connected Mms1 function to genome integrity and replication fork progression at particular G-rich motifs. This motif can form G-quadruplex (G4) structures in vitro. G4 are stable DNA structures that are known to impede replication fork progression. In the absence of Mms1, genome stability is at risk at these G-rich/G4 regions as demonstrated by gross chromosomal rearrangement assays. Mms1 binds throughout the cell cycle to these G-rich/G4 regions and supports the binding of Pif1 DNA helicase. Based on these data we propose a mechanistic model in which Mms1 binds to specific G-rich/G4 motif located on the lagging strand template for DNA replication and supports Pif1 function, DNA replication and genome integrity.
Previous studies have shown that ingroup/outgroup membership influences individual’s fairness considerations. However, it is not clear yet how group membership influences brain activity when a recipient evaluates the fairness of asset distribution. In this study, subjects participated as recipients in an Ultimatum Game with alleged members of both an experimentally induced ingroup and outgroup. They either received extremely unequal, moderately unequal, or equal offers from proposers while electroencephalogram was recorded. Behavioral results showed that the acceptance rates for unequal offers were higher when interacting with ingroup partners than with outgroup partners. Analyses of event related potentials revealed that proposers’ group membership modulated offer evaluation at earlier processing stages. Feedback-related negativity was more negative for extremely and moderately unequal offers compared to equal offers in the ingroup interaction whereas it did not show differential responses to different offers in the outgroup interaction. Analyses of event related oscillations revealed that the theta power (4–6 Hz) was larger for moderately unequal offers than equal offers in the ingroup interaction whereas it did not show differential responses to different offers in the outgroup interaction. Thus, early mechanisms of fairness evaluation are strongly modulated by the ingroup/outgroup membership of the interaction partner.
Upon complexation to CuOTf, a PMe\(_3\)-stabilized bis(9-anthryl) diborene slowly undergoes an intramolecular hydroarylation reaction at room temperature. Subsequent triflation of the B–H bond with CuOTf, followed by a PMe\(_3\) transfer, finally yields a cyclic sp\(^2\)-sp\(^3\) boryl-substituted boronium triflate salt.
Despite the prevalence of stable π-complexes of most d\(^{10}\) metals, such as Cu(I) and Ni(0), with ethylene and other olefins, complexation of d\(^{10}\) Zn(II) to simple olefins is too weak to form isolable complexes due to the metal ion's limited capacity for π-backdonation. By employing more strongly donating π- ligands, namely neutral diborenes with a high-lying π(B=B) or- bital, monomeric 16-electron M(II)-diborene (M = Zn, Cd) π- complexes were synthesized in good yields. Metal–B2 π- interactions in both the solid and solution state were confirmed by single-crystal X-ray analyses and their solution NMR and UV-vis absorption spectroscopy, respectively. The M(II) centers adopt a trigonal planar geometry and interact almost symmetrically with both boron atoms. The MB2 planes significantly twist out of the MX\(_2\) planes about the M-centroid(B–B) vector, with angles rang- ing from 47.0° to 85.5°, depending on the steric interactions be- tween the diborene ligand and the MX\(_2\) fragment.
The diborene 1 was synthesized by reduction of a mixture of 1,2-di-9-anthryl-1,2-dibromodiborane(4) (6) and trimethylphosphine with potassium graphite. The X-ray structure of 1 shows the two anthryl rings to be parallel and their π(C\(_{14}\)) systems perpendicular to the diborene π(B=B) system. This twisted conformation allows for intercalation of the relatively high-lying π(B=B) orbital and the low-lying π* orbital of the anthryl moiety with no significant conjugation, resulting in a small HOMO-LUMO gap (HLG) and ultimately an unprecedented anthryl B–B bond hydroarylation. The HLG of 1 was estimated to be 1.57 eV from the onset of the long wavelength band in its UV–vis absorption spectrum (THF, λ\(_{onset}\) = 788 nm). The oxidation of 1 with elemental selenium afforded diboraselenirane 8 in quantitative yield. By oxidative abstraction of one phosphine ligand by another equivalent of elemental selenium, the B–B and C\(^1\)–H bonds of 8 were cleaved to give the cyclic 1,9-diboraanthracene 9.
α-Synuclein is a protein implicated in the etiopathogenesis of Parkinson’s disease (PD). AAV1/2-driven overexpression of human mutated A53T-α-synuclein in rat and monkey substantia nigra (SN) induces degeneration of nigral dopaminergic neurons and decreases striatal dopamine and tyrosine hydroxylase (TH). Given certain advantages of the mouse, especially it being amendable to genetic manipulation, translating the AAV1/2-A53T α-synuclein model to mice would be of significant value. AAV1/2-A53T α-synuclein or AAV1/2 empty vector (EV) at a concentration of 5.16 x 10\(^{12}\) gp/ml were unilaterally injected into the right SN of male adult C57BL/6 mice. Post-mortem examinations included immunohistochemistry to analyze nigral α-synuclein, Ser129 phosphorylated α-synuclein and TH expression, striatal dopamine transporter (DAT) levels by autoradiography and dopamine levels by high performance liquid chromatography. At 10 weeks, in AAV1/2-A53T α-synuclein mice there was a 33% reduction in TH+ dopaminergic nigral neurons (P < 0.001), 29% deficit in striatal DAT binding (P < 0.05), 38% and 33% reductions in dopamine (P < 0.001) and DOPAC (P < 0.01) levels and a 60% increase in dopamine turnover (homovanilic acid/dopamine ratio; P < 0.001). Immunofluorescence showed that the AAV1/2-A53T α-synuclein injected mice had widespread nigral and striatal expression of vector-delivered A53T-α-synuclein. Concurrent staining with human PD SN samples using gold standard histological methodology for Lewy pathology detection by proteinase K digestion and application of specific antibody raised against human Lewy body α-synuclein (LB509) and Ser129 phosphorylated α-synuclein (81A) revealed insoluble α-synuclein aggregates in AAV1/2-A53T α-synuclein mice resembling Lewy-like neurites and bodies. In the cylinder test, we observed significant paw use asymmetry in the AAV1/2-A53T α-synuclein group when compared to EV controls at 5 and 9 weeks post injection (P < 0.001; P < 0.05). These data show that unilateral injection of AAV1/2-A53T α-synuclein into the mouse SN leads to persistent motor deficits, neurodegeneration of the nigrostriatal dopaminergic system and development of Lewy-like pathology, thereby reflecting clinical and pathological hallmarks of human PD.
Background:
Sit-to-stand height-adjustable desks (HAD) may promote workplace standing, as long as workers use them on a regular basis. The aim of this study was to investigate (i) how common HAD in German desk-based workers are, and how frequently HADs are used, (ii) to identify sociodemographic, health-related, and psycho-social variables of workday sitting including having a HAD, and (iii) to analyse sociodemographic, health-related, and psycho-social variables of users and non-users of HADs.
Methods:
A cross-sectional sample of 680 participants (51.9% men; 41.0 ± 13.1 years) in a desk-based occupation was interviewed by telephone about their occupational sitting and standing proportions, having and usage of a HAD, and answered questions concerning psycho-social variables of occupational sitting. The proportion of workday sitting was calculated for participants having an HAD (n = 108) and not-having an HAD (n = 573), as well as for regular users of HAD (n = 54), and irregular/non-users of HAD (n = 54). Linear regressions were conducted to calculate associations between socio-demographic, health-related, psychosocial variables and having/not having an HAD, and the proportion of workday sitting. Logistic regressions were executed to examine the association of mentioned variables and participants’ usage of HADs.
Results:
Sixteen percent report that they have an HAD, and 50% of these report regular use of HAD. Having an HAD is not a correlate of the proportion of workday sitting. Further analysis restricted to participants having available a HAD highlights that only the ‘perceived advantages of sitting less’ was significantly associated with HAD use in the fully adjusted model (OR 1.75 [1.09; 2.81], p < 0.05).
Conclusions:
The present findings indicate that accompanying behavioral action while providing an HAD is promising to increase the regular usage of HAD. Hence, future research needs to address the specificity of behavioral actions in order to enhance regular HAD use, and needs to give more fundamental insights into these associations.
Multiple lines of evidence implicate brain serotonin (5-hydroxytryptamine; 5-HT) system dysfunction in the pathophysiology of stressor-related and anxiety disorders. Here we investigate the influence of constitutively deficient 5-HT synthesis on stressor-related anxiety-like behaviors using Tryptophan hydroxylase 2 (Tph2) mutant mice. Functional assessment of c-Fos after associated foot shock, electrophysiological recordings of GABAergic synaptic transmission, differential expression of the Slc6a4 gene in serotonergic neurons were combined with locomotor and anxiety-like measurements in different contextual settings. Our findings indicate that constitutive Tph2 inactivation and consequential lack of 5-HT synthesis in Tph2 null mutant mice (Tph2\(^{-/-}\)) results in increased freezing to associated foot shock and a differential c-Fos activity pattern in the basolateral complex of the amygdala. This is accompanied by altered GABAergic transmission as observed by recordings of inhibitory postsynaptic currents on principal neurons in the basolateral nucleus, which may explain increased fear associated with hyperlocomotion and escape-like responses in aversive inescapable contexts. In contrast, lifelong 5-HT deficiency as observed in Tph2 heterozygous mice (Tph\(^{+/-}\)) is able to be compensated through reduced GABAergic transmission in the basolateral nucleus of the amygdala based on Slc6a4 mRNA upregulation in subdivisions of dorsal raphe neurons. This results in increased activity of the basolateral nucleus of the amygdala due to associated foot shock. In conclusion, our results reflect characteristic syndromal dimensions of panic disorder and agoraphobia. Thus, constitutive lack of 5-HT synthesis influence the risk for anxiety- and stressor-related disorders including panic disorder and comorbid agoraphobia through the absence of GABAergic-dependent compensatory mechanisms in the basolateral nucleus of the amygdala.
Background
Chronic kidney disease (CKD) is a common comorbid condition in coronary heart disease (CHD). CKD predisposes the patient to acute kidney injury (AKI) during hospitalization. Data on awareness of kidney dysfunction among CHD patients and their treating physicians are lacking. In the current cross-sectional analysis of the German EUROASPIRE IV sample we aimed to investigate the physician’s awareness of kidney disease of patients hospitalized for CHD and also the patient’s awareness of CKD in a study visit following hospital discharge.
Methods
All serum creatinine (SCr) values measured during the hospital stay were used to describe impaired kidney function (eGFR\(_{CKD-EPI}\) < 60 ml/min/1.73m2) at admission, discharge and episodes of AKI (KDIGO definition). Information extracted from hospital discharge letters and correct ICD coding for kidney disease was studied as a surrogate of physician’s awareness of kidney disease. All patients were interrogated 0.5 to 3 years after hospital discharge, whether they had ever been told about kidney disease by a physician.
Results
Of the 536 patients, 32% had evidence for acute or chronic kidney disease during the index hospital stay. Either condition was mentioned in the discharge letter in 22%, and 72% were correctly coded according to ICD-10. At the study visit in the outpatient setting 35% had impaired kidney function. Of 158 patients with kidney disease, 54 (34%) were aware of CKD. Determinants of patient’s awareness were severity of CKD (OR\(_{eGFR}\) 0.94; 95%CI 0.92–0.96), obesity (OR 1.97; 1.07–3.64), history of heart failure (OR 1.99; 1.00–3.97), and mentioning of kidney disease in the index event’s hospital discharge letter (OR 5.51; 2.35–12.9).
Conclusions
Although CKD is frequent in CHD, only one third of patients is aware of this condition. Patient’s awareness was associated with kidney disease being mentioned in the hospital discharge letter. Future studies should examine how raising physician’s awareness for kidney dysfunction may improve patient’s awareness of CKD.
Echinocandin antifungals represent one of the most important drug classes for the treatment of invasive fungal infections. The mode of action of the echinocandins relies on inhibition of the β-1,3-glucan synthase, an enzyme essentially required for the synthesis of the major fungal cell wall carbohydrate β-1,3-glucan. Depending on the species, echinocandins may exert fungicidal or fungistatic activity. Apparently independent of this differential activity, a surprising in vitro phenomenon called the “paradoxical effect” can be observed. The paradoxical effect is characterized by the ability of certain fungal isolates to reconstitute growth in the presence of higher echinocandin concentrations, while being fully susceptible at lower concentrations. The nature of the paradoxical effect is not fully understood and has been the focus of multiple studies in the last two decades. Here we concisely review the current literature and propose an updated model for the paradoxical effect, taking into account recent advances in the field.
Tinnitus is the perception of a phantom sound that affects between 10 and 15% of the general population. Despite this considerable prevalence, treatments for tinnitus are presently lacking. Tinnitus exhibits a diverse array of recognized risk factors and extreme clinical heterogeneity. Furthermore, it can involve an unknown number of auditory and non-auditory networks and molecular pathways. This complex combination has hampered advancements in the field. The identification of specific genetic factors has been at the forefront of several research investigations in the past decade. Nine studies have examined genes in a case-control association approach. Recently, a genome-wide association study has highlighted several potentially significant pathways that are implicated in tinnitus. Two twin studies have calculated a moderate heritability for tinnitus and disclosed a greater concordance rate in monozygotic twins compared to dizygotic twins. Despite the more recent data alluding to genetic factors in tinnitus, a strong association with any specific genetic locus is lacking and a genetic study with sufficient statistical power has yet to be designed. Future research endeavors must overcome the many inherent limitations in previous study designs. This review summarizes the previously embarked upon tinnitus genetic investigations and summarizes the hurdles that have been encountered. The identification of candidate genes responsible for tinnitus may afford gene based diagnostic approaches, effective therapy development, and personalized therapeutic intervention.
In this article, we present approaches to interactive simulations of biohybrid systems. These simulations are comprised of two major computational components: (1) agent-based developmental models that retrace organismal growth and unfolding of technical scaffoldings and (2) interfaces to explore these models interactively. Simulations of biohybrid systems allow us to fast forward and experience their evolution over time based on our design decisions involving the choice, configuration and initial states of the deployed biological and robotic actors as well as their interplay with the environment. We briefly introduce the concept of swarm grammars, an agent-based extension of L-systems for retracing growth processes and structural artifacts. Next, we review an early augmented reality prototype for designing and projecting biohybrid system simulations into real space. In addition to models that retrace plant behaviors, we specify swarm grammar agents to braid structures in a self-organizing manner. Based on this model, both robotic and plant-driven braiding processes can be experienced and explored in virtual worlds. We present an according user interface for use in virtual reality. As we present interactive models concerning rather diverse description levels, we only ensured their principal capacity for interaction but did not consider efficiency analyzes beyond prototypic operation. We conclude this article with an outlook on future works on melding reality and virtuality to drive the design and deployment of biohybrid systems.
Nonalcoholic fatty liver disease, induced by a Western diet (WD), evokes central and peripheral inflammation that is accompanied by altered emotionality. These changes can be associated with abnormalities in social behaviour, hippocampus-dependent cognitive functions, and metabolism. Female C57BL/6J mice were fed with a regular chow or with a WD containing 0.2% of cholesterol and 21% of saturated fat for three weeks. WD-treated mice exhibited increased social avoidance, crawl-over and digging behaviours, decreased body-body contacts, and hyperlocomotion. The WD-fed group also displayed deficits in hippocampal-dependent performance such as contextual memory in a fear conditioning and pellet displacement paradigms. A reduction in glucose tolerance and elevated levels of serum cholesterol and leptin were also associated with the WD. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1a) mRNA, a marker of mitochondrial activity, was decreased in the prefrontal cortex, hippocampus, hypothalamus, and dorsal raphe, suggesting suppressed brain mitochondrial functions, but not in the liver. This is the first report to show that a WD can profoundly suppress social interactions and induce dominant-like behaviours in naïve adult mice. The spectrum of behaviours that were found to be induced are reminiscent of symptoms associated with autism, and, if paralleled in humans, suggest that a WD might exacerbate autism spectrum disorder.
Background:
Contrast-enhanced cardiovascular magnetic resonance angiography (CE-CMRA) is the established imaging modality for patients with Marfan syndrome requiring life-long annual aortic imaging before and after aortic root replacement. Contrast-free CMRA techniques avoiding side-effects of contrast media are highly desirable for serial imaging but have not been evaluated in the postoperative setup of Marfan patients. The purpose of this study was to assess the feasibility of non-contrast balanced steady-state free precession (bSSFP) magnetic resonance imaging for aortic monitoring of postoperative patients with Marfan syndrome.
Methods:
Sixty-four adult Marfan patients after aortic root replacement were prospectively included. Fourteen patients (22%) had a residual aortic dissection after surgical treatment of type A dissection. bSSFP imaging and CE-CMRA were performed at 1.5 Tesla. Two radiologists evaluated the images regarding image quality (1 = poor, 4 = excellent), artifacts (1 = severe, 4 = none) and aortic pathologies. Readers measured the aortic diameters at defined levels in both techniques. Statistics included observer agreement for image scoring and diameter measurements and ROC analyses for comparison of the diagnostic performance of bSSFP and CE-CMRA.
Results:
Both readers observed no significant differences in image quality between bSSFP and CE-CMRA and found a median image quality score of 4 for both techniques (all p > .05). No significant differences were found regarding the frequency of image artifacts in both sequences (all p > .05). Sensitivity and specificity for detection of aortic dissections was 100% for both readers and techniques. Compared to bSSFP imaging, CE-CMRA resulted in higher diameters (mean bias, 0.9 mm; p < .05). The inter-observer biases of diameter measurements were not significantly different (all p > .05), except for the distal graft anastomosis (p = .001). Using both techniques, the readers correctly identified a graft suture dehiscence with aneurysm formation requiring surgery.
Conclusion:
Unenhanced bSSFP CMR imaging allows for riskless aortic monitoring with high diagnostic accuracy in Marfan patients after aortic root surgery.
Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against E. coli (ATCC 11775 and 25922) and their cytotoxic effect against MDA-MB-468 and MDA-MB-231 breast cancer cell lines were evaluated. Dimeric and tetrameric peptides showed higher antibacterial activity in both bacteria strains than linear peptides. The dimeric peptide (RRWQWR)\(_2\)K-Ahx exhibited the highest antibacterial activity against the tested bacterial strains. Furthermore, the peptides with high antibacterial activity exhibited significant cytotoxic effect against the tested breast cancer cell lines. This cytotoxic effect was fast and dependent on the peptide concentration. The tetrameric molecule containing RRWQWR motif has an optimal cytotoxic effect at a concentration of 22 µM. The evaluated dimeric and tetrameric peptides could be considered as candidates for developing new therapeutic agents against breast cancer. Polyvalence of linear sequences could be considered as a novel and versatile strategy for obtaining molecules with high anticancer activity.
Background: There is increasing evidence for the role of prenatal stress in shaping offspring DNA methylation and disease susceptibility. In the current study, we aimed to identify genes and pathways associated with pregnancy anxiety using a genome-wide DNA methylation approach.
Methods: We selected 22 versus 23 newborns from our Prenatal Early Life Stress (PELS) cohort, exposed to the lowest or highest degree of maternal pregnancy anxiety, respectively. Cord blood genome-wide DNA methylation was assayed using the HumanMethylation450 BeadChip (HM450, n = 45) and candidate gene methylation using EpiTYPER (n = 80). Cortisol levels were measured at 2, 4, and 12 months of age to test infant stress system (re)activity.
Results: Data showed ten differentially methylated regions (DMR) when comparing newborns exposed to low versus high pregnancy anxiety scores. We validated a top DMR in the GABA-B receptor subunit 1 gene (GABBR1) revealing the association with pregnancy anxiety particularly in male newborns (most significant CpG Pearson R = 0.517, p = 0.002; average methylation Pearson R = 0.332, p = 0.039). Cord blood GABBR1 methylation was associated with infant cortisol levels in response to a routine vaccination at 4 months old.
Conclusions: In conclusion, our results show that pregnancy anxiety is associated with differential DNA methylation patterns in newborns and that our candidate gene GABBR1 is associated with infant hypothalamic-pituitary-adrenal axis response to a stressor. Our findings reveal a potential role for GABBR1 methylation in association with stress and provide grounds for further research.
Hyperglycemia (HG) stimulates the production of reactive oxygen species in the heart through activation of NADPH oxidase 2 (NOX2). This production is independent of glucose metabolism but requires sodium/glucose cotransporters (SGLT). Seven SGLT isoforms (SGLT1 to 6 and sodium-myoinositol cotransporter-1, SMIT1) are known, although their expression and function in the heart remain elusive. We investigated these 7 isoforms and found that only SGLT1 and SMIT1 were expressed in mouse, rat and human hearts. In cardiomyocytes, galactose (transported through SGLT1) did not activate NOX2. Accordingly, SGLT1 deficiency did not prevent HG-induced NOX2 activation, ruling it out in the cellular response to HG. In contrast, myo-inositol (transported through SMIT1) reproduced the toxic effects of HG. SMIT1 overexpression exacerbated glucotoxicity and sensitized cardiomyocytes to HG, whereas its deletion prevented HG-induced NOX2 activation. In conclusion, our results show that heart SMIT1 senses HG and triggers NOX2 activation. This could participate in the redox signaling in hyperglycemic heart and contribute to the pathophysiology of diabetic cardiomyopathy.
Acute graft-versus-host disease (aGvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell plus T cell transplantation (allo-HSCT). In this study, we investigated the requirement for CD28 co-stimulation of donor CD4\(^{+}\) conventional (CD4\(^{+}\)CD25\(^{-}\)Foxp3\(^{-}\), Tconv) and regulatory (CD4\(^{+}\)CD25\(^{+}\)Foxp3\(^{+}\), Treg) T cells in aGvHD using tamoxifen-inducible CD28 knockout (iCD28KO) or wild-type (wt) littermates as donors of CD4\(^{+}\) Tconv and Treg. In the highly inflammatory C57BL/6 into BALB/c allo-HSCT transplantation model, CD28 depletion on donor CD4\(^{+}\) Tconv reduced clinical signs of aGvHD, but did not significantly prolong survival of the recipient mice. Selective depletion of CD28 on donor Treg did not abrogate protection of recipient mice from aGvHD until about day 20 after allo-HSCT. Later, however, the pool of CD28-depleted Treg drastically declined as compared to wt Treg. Consequently, only wt, but not CD28-deficient, Treg were able to continuously suppress aGvHD and induce long-term survival of the recipient mice. To our knowledge, this is the first study that specifically evaluates the impact of CD28 expression on donor Treg in aGvHD. Moreover, the delayed kinetics of aGvHD lethality after transplantation of iCD28KO Treg provides a novel animal model for similar disease courses found in patients after allo-HSCT.
In this study, polarimetric Synthetic Aperture Radar (PolSAR) data at X-, C- and L-Bands, acquired by the satellites: TerraSAR-X (2011), Radarsat-2 (2011), ALOS (2010) and ALOS-2 (2016), were used to characterize the tundra land cover of a test site located close to the town of Tuktoyaktuk, NWT, Canada. Using available in situ ground data collected in 2010 and 2012, we investigate PolSAR scattering characteristics of common tundra land cover classes at X-, C- and L-Bands. Several decomposition features of quad-, co-, and cross-polarized data were compared, the correlation between them was investigated, and the class separability offered by their different feature spaces was analyzed. Certain PolSAR features at each wavelength were sensitive to the land cover and exhibited distinct scattering characteristics. Use of shorter wavelength imagery (X and C) was beneficial for the characterization of wetland and tundra vegetation, while L-Band data highlighted differences of the bare ground classes better. The Kennaugh Matrix decomposition applied in this study provided a unified framework to store, process, and analyze all data consistently, and the matrix offered a favorable feature space for class separation. Of all elements of the quad-polarized Kennaugh Matrix, the intensity based elements K0, K1, K2, K3 and K4 were found to be most valuable for class discrimination. These elements contributed to better class separation as indicated by an increase of the separability metrics squared Jefferys Matusita Distance and Transformed Divergence. The increase in separability was up to 57% for Radarsat-2 and up to 18% for ALOS-2 data.
Low-energy spin excitations in any long-range ordered magnetic system in the absence of magnetocrystalline anisotropy are gapless Goldstone modes emanating from the ordering wave vectors. In helimagnets, these modes hybridize into the so-called helimagnon excitations. Here we employ neutron spectroscopy supported by theoretical calculations to investigate the magnetic excitation spectrum of the isotropic Heisenberg helimagnet \({ZnCr_2Se_4}\) with a cubic spinel structure, in which spin\(-3/2\) magnetic \({Cr^{3+}}\) ions are arranged in a geometrically frustrated pyrochlore sublattice. Apart from the conventional Goldstone mode emanating from the \((0~ 0~ {q_h})\) ordering vector, low-energy magnetic excitations in the single-domain proper-screw spiral phase show soft helimagnon modes with a small energy gap of \({∼0.17~ meV}\), emerging from two orthogonal wave vectors \(({q_h}~ 0~ 0)\) and \({(0~ {q_h}~ 0)}\) where no magnetic Bragg peaks are present. We term them pseudo-Goldstone magnons, as they appear gapless within linear spinwave theory and only acquire a finite gap due to higher-order quantum-fluctuation corrections. Our results are likely universal for a broad class of symmetric helimagnets, opening up a new way of studying weak magnon-magnon interactions with accessible spectroscopic methods.
Just as photons are the quanta of light, plasmons are the quanta of orchestrated charge-density oscillations in conducting media. Plasmon phenomena in normal metals, superconductors, and doped semiconductors are often driven by long-wavelength Coulomb interactions. However, in crystals whose Fermi surface is comprised of disconnected pockets in the Brillouin zone, collective electron excitations can also attain a shortwave component when electrons transition between these pockets. In this work, we show that the band structure of monolayer transition-metal dichalcogenides gives rise to an intriguing mechanism through which shortwave plasmons are paired up with excitons. The coupling elucidates the origin for the optical sideband that is observed repeatedly in monolayers of WSe\(_2\) and WS\(_2\) but not understood. The theory makes it clear why exciton-plasmon coupling has the right conditions to manifest itself distinctly only in the optical spectra of electron-doped tungsten-based monolayers.
Oncolytic vaccinia virus (VACV) therapy is an alternative cancer treatment modality that mediates targeted tumor destruction through a tumor-selective replication and an induction of anti-tumor immunity. We developed a humanized tumor mouse model with subcutaneous human tumors to analyze the interactions of VACV with the developing tumors and human immune system. A successful systemic reconstitution with human immune cells including functional T cells as well as development of tumors infiltrated with human T and natural killer (NK) cells was observed. We also demonstrated successful in vivo colonization of such tumors with systemically administered VACVs. Further, a new recombinant GLV-1h376 VACV encoding for a secreted human CTLA4-blocking single-chain antibody (CTLA4 scAb) was tested. Surprisingly, although proving CTLA4 scAb’s in vitro binding ability and functionality in cell culture, beside the significant increase of CD56\(^{bright}\) NK cell subset, GLV-1h376 was not able to increase cytotoxic T or overall NK cell levels at the tumor site. Importantly, the virus-encoded β-glucuronidase as a measure of viral titer and CTLA4 scAb amount was demonstrated. Therefore, studies in our “patient-like” humanized tumor mouse model allow the exploration of newly designed therapy strategies considering the complex relationships between the developing tumor, the oncolytic virus, and the human immune system.
A promising new approach for the treatment of human cancer is the use of oncolytic viruses, which exhibit tumor tropism. One of the top candidates in this area is the oncolytic vaccinia virus (VACV), which has already shown promising results in animal studies and in clinical trials. However, due to discrepancies in both innate and adaptive immunity between mice and men the evaluation of the vaccinia virus’ interactions with the host immune system in mice are not fully conclusive of what is actually happening in human cancer patients after systemic administration of vaccinia virus. Also, ethical and legal concerns as well as risk of potential toxicity limit research involving human patients. Therefore, a good in vivo model for testing interactions between vaccinia virus and human immune cells, avoiding the numerous limitations and risks associated with human studies, could be a humanized mouse model.
LIVP-1.1.1, GLV-2b372, GLV-1h68, GLV-1h375, GLV-1h376 and GLV-1h377 VACVs were provided by Genelux Corporation. GLV-2b372 was constructed by inserting TurboFP635 expression cassette into the J2R locus of the parental LIVP-1.1.1. GLV-1h375, -1h376 and -1h377 VACVs encode the human CTLA4-blocking single-chain antibody (CTLA4 scAb). Performed replication and cytotoxicity assays demonstrated that all six viruses were able to infect, replicate in and kill human tumor cells in virus-dose- and time-dependent fashion. CTLA4 scAb and β-glucuronidase (GusA) expression as well as viral titers in GLV-1h376-infected cells were analyzed by ELISA, β-glucuronidase assay and standard plaque assay, respectively, and compared. An excellent correlation with correlation coefficients R2>0.9806 were observed. GLV-1h376-encoded CTLA4 scAb was successfully purified from supernatants of infected CV-1 cells and demonstrated in vitro affinity to its human CTLA4 target and lack of cross-reactivity to mouse CTLA4. CTLA4 scAb functionality was confirmed in Jurkat cells. LIVP-1.1.1, GLV-2b372, GLV-1h68 and GLV-1h376 were next studied in non-tumorous and/or tumor-bearing humanized mice.
It was demonstrated that injection of human CD34+ stem cells into the liver of preconditioned newborn NSG mice let to a successful systemic reconstitution with human immune cells. CD19+ B cells, CD4 and CD8 single positive CD3+ T cell, NKp46+CD56- and NKp46+CD56+ NK cells as well as CD33+ myeloid cells developed. At early time points after engraftment, majority of the human hematopoietic cells detected in the mouse blood were CD19+ B cells and only a small portion were CD3+ T cells. With time a significant change in CD19+/CD3+ ratio was reported with a decrease of B cells and an increase of T cells. Implantation of A549 cells under the skin of those humanized NSG mice resulted in a progressive tumor growth, described for the first time in this thesis. Successful colonization of subcutaneous A549 tumors with VACVs was visualized and demonstrated by detection of virus-mediated TurboFP635 and GFP expression as well as by standard plaque assay and immunohistochemistry. The human CD45+ cell population in tumors was represented mainly by NKp46+CD56bright NK cells and a large portion of activated CD4+ and cytotoxic CD8+ T cells. However, no significant differences were observed between control and LIVP-1.1.1-infected tumors, suggesting that the recruitment of NK and activated T cells were more tumor tissue specific than virus-dependent. Unfortunately, virus-mediated CTLA4 scAb expression in the GLV-1h376-infected tumors was also not able to significantly increase activation of T cells compared to control and GLV-1h68-treated mice. Importantly, ELISA, β-glucuronidase and standard plaque assays showed an excellent correlation with correlation coefficients R2>0.9454 between CTLA4 scAb, GusA concentrations and viral titers in tumor samples from those GLV-1h376 treated mice.
T cells isolated from the spleens of such control or GLV-1h68- or -1h376-treated A549 tumor-bearing mice were functional and could successfully be activated with human T cells activation beads. However, although no significant difference was observed between the three mouse groups, a slightly higher percentage of the GLV-1h376-treated mice-derived T cells were expressing CD25 and producing IFN-ɣ after ex vivo activation, probably due to the CTLA4 blockade by the virus-encoded CTLA4 scAb in the GLV-1h376-treated mice. Also, slightly higher levels of IL-2 were detected in the culture supernatant of those splenocytes compared to control samples. In contrast, T cells from all three mouse groups were not able be activated by A549 tumor cells ex vivo.
Our model has the specific advantage that tumors develop under the skin of the humanized mice, which allows accurate monitoring of the tumor growth and evaluation of the oncolytic virotherapy. Therefore it is important to choose the right approaches for its further improvement.
Three unusual heterodimeric naphthylisoquinoline alkaloids, named ealapasamines A-C (1–3), were isolated from the leaves of the tropical plant Ancistrocladus ealaensis J. Léonard. These ‘mixed’, constitutionally unsymmetric dimers are the first stereochemically fully assigned cross-coupling products of a 5,8′- and a 7,8′-coupled naphthylisoquinoline linked via C-6′ in both naphthalene portions. So far, only two other West and Central Ancistrocladus species were known to produce dimers with a central 6,6″-axis, yet, in contrast to the ealapasamines, usually consisting of two 5,8′-coupled monomers, like e.g., in michellamine B. The new dimers 1–3 contain six elements of chirality, four stereogenic centers and the two outer axes, while the central biaryl axis is configurationally unstable. The elucidation of the complete stereostructures of the ealapasamines was achieved by the interplay of spectroscopic methods including HRESIMS, 1D and 2D NMR (in particular ROESY measurements), in combination with chemical (oxidative degradation) and chiroptical (electronic circular dichroism) investigations. The ealapasamines A-C display high antiplasmodial activities with excellent half-maximum inhibition concentration values in the low nanomolar range.
The immunomodulatory role of human leukocyte antigen (HLA)-E in hematopoietic stem cell transplantation (HSCT) has not been extensively investigated. To this end, we genotyped 509 10/10 HLA unrelated transplant pairs for HLA-E, in order to study the effect of HLA-E as a natural killer (NK)-alloreactivity mediator on HSCT outcome in an acute leukemia (AL) setting. Overall survival (OS), disease free survival (DFS), relapse incidence (RI) and non-relapse mortality (NRM) were set as endpoints. Analysis of our data revealed a significant correlation between HLA-E mismatch and improved HSCT outcome, as shown by both univariate (53% vs. 38%, P=0.002, 5-year OS) and multivariate (hazard ratio (HR)=0.63, confidence interval (CI) 95%=0.48–0.83, P=0.001) analyses. Further subgroup analysis demonstrated that the positive effect of HLA-E mismatch was significant and pronounced in advanced disease patients (n=120) (5-year OS: 50% vs. 18%, P=0.005; HR=0.40, CI 95%=0.22–0.72, P=0.002; results from univariate and multivariate analyses, respectively). The study herein is the first to report an association between HLA-E incompatibility and improved post–transplant prognosis in AL patients who have undergone matched unrelated HSCT. Combined NK and T cell HLA-E-mediated mechanisms may account for the better outcomes observed. Notwithstanding the necessity for in vitro and confirmational studies, our findings highlight the clinical relevance of HLA-E matching and strongly support prospective HLA-E screening upon donor selection for matched AL unrelated HSCTs.
Reproducibility and comparison of oxygen-enhanced T\(_1\) quantification in COPD and asthma patients
(2017)
T\(_1\) maps have been shown to yield useful diagnostic information on lung function in patients with chronic obstructive pulmonary disease (COPD) and asthma, both for native T\(_1\) and ΔT\(_1\), the relative reduction while breathing pure oxygen. As parameter quantification is particularly interesting for longitudinal studies, the purpose of this work was both to examine the reproducibility of lung T\(_1\) mapping and to compare T\(_1\) found in COPD and asthma patients using IRSnapShotFLASH embedded in a full MRI protocol. 12 asthma and 12 COPD patients (site 1) and further 15 COPD patients (site 2) were examined on two consecutive days. In each patient, T\(_1\) maps were acquired in 8 single breath-hold slices, breathing first room air, then pure oxygen. Maps were partitioned into 12 regions each to calculate average values. In asthma patients, the average T\(_{1,RA}\) = 1206ms (room air) was reduced to T\(_{1,O2}\) = 1141ms under oxygen conditions (ΔT\(_1\) = 5.3%, p < 5⋅10\(^{−4})\), while in COPD patients both native T\(_{1,RA}\) = 1125ms was significantly shorter (p < 10\(^{−3})\) and the relative reduction to T\(_{1,O2}\) = 1081ms on average ΔT\(_1\) = 4.2%(p < 10\(^{−5}\)). On the second day, with T\(_{1,RA}\) = 1186ms in asthma and T\(_{1,RA}\) = 1097ms in COPD, observed values were slightly shorter on average in all patient groups. ΔT\(_1\) reduction was the least repeatable parameter and varied from day to day by up to 23% in individual asthma and 30% in COPD patients. While for both patient groups T\(_1\) was below the values reported for healthy subjects, the T\(_1\) and ΔT\(_1\) found in asthmatics lies between that of the COPD group and reported values for healthy subjects, suggesting a higher blood volume fraction and better ventilation. However, it could be demonstrated that lung T\(_1\) quantification is subject to notable inter-examination variability, which here can be attributed both to remaining contrast agent from the previous day and the increased dependency of lung T\(_1\) on perfusion and thus current lung state.
Background:
While data from primary care suggest an insufficient control of vascular risk factors, little is known about vascular risk factor control in the general population. We therefore aimed to investigate the adoption of adequate risk factor control and its determinants in the general population free of cardiovascular disease (CVD).
Methods:
Data from the Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression (STAAB) Cohort Study, a population-based study of inhabitants aged 30 to 79 years from the general population of Würzburg (Germany), were used. Proportions of participants without established CVD meeting targets for risk factor control recommended by 2016 ESC guideline were identified. Determinants of the accumulation of insufficiently controlled vascular risk factors (three or more) were assessed.
Results:
Between December 2013 and April 2015, 1379 participants without CVD were included; mean age was 53.1 ± 11.9 years and 52.9% were female; 30.8% were physically inactive, 55.2% overweight, 19.3% current smokers. Hypertension, dyslipidemia, and diabetes mellitus were prevalent in 31.8%, 57.6%, and 3.9%, respectively. Treatment goals were not reached despite medication in 52.7% of hypertensive, in 37.3% of hyperlipidemic and in 44.0% of diabetic subjects. Insufficiently controlled risk was associated with male sex (OR 1.94, 95%CI 1.44–2.61), higher age (OR for 30–39 years vs. 70–79 years 4.01, 95%CI 1.94–8.31) and lower level of education (OR for primary vs. tertiary 2.15, 95%CI 1.48–3.11).
Conclusions:
In the general population, prevalence of vascular risk factors was high. We found insufficient identification and control of vascular risk factors and a considerable potential to improve adherence to cardiovascular guidelines for primary prevention. Further studies are needed to identify and overcome patient- and physician-related barriers impeding successful control of vascular risk factors in the general population.
In this work fluorescence-based single molecule detection at low concetration is investigated, with an emphasis on the usage of active transport and waveguides.
Active transport allows to overcome the limits of diffusion-based systems in terms of the lowest detectable threshold of concentration.
The effect of flow in single molecule experiments is investigated and a theoretical model is derived for laminar flow.
Waveguides on the other hand promise compact detection schemes and show great potential for their possible integration into lab-on-a-chip applications. Their properties in single molecule experiments are analyzed with help of a method based on the reciprocity theorem of electromagnetic theory.
Successful formulation development of novel, particularly organic APIs of low molecular weight as candidates for ground-breaking pharmaceutical products is a major challenge for the pharmaceutical industry because of the poor aqueous solubility of most of these compounds.
The hit identification strategies of drug development in use today apply high throughput screening techniques for the investigation of thousands of substances. This approach led to a systematical increase in molecular weight and lipophilicity and a decrease of water solubility of lead compounds reaching market access.
The high lipophilicity causes an excellent permeability of the compounds which favours the absorption process from the small intestine, but it causes a decrease of water-solubility. It becomes evident that an adequate aqueous solubility is necessary for absorption of the API from the gastrointestinal fluids into the systemic circulation and hence for efficacy of the pharmaceutical product. Only an dissolved API is getting absorbed and becomes efficacious. The precipitated proportion is resigned directly. Therefore, the development of an individual formulation aligning the physicochemical characteristics is necessary for every API to produce supersaturated solutions in the small intestine and to reach an adequate bioavailability after absorption into the systemic circulation.
In this thesis a specific formulation development was investigated for two exemplary poorly water-soluble APIs to replace the empirical approach often used today. The basic tyrosine-kinase inhibitor imatinib and six different acetylated amino acids were transferred into ILs. As compared to the free base and the mesylate salt, which is marketed by Novartis AG as Gleevec®, the dissolution rate as well as the supersaturation time was increased significantly. By changing the mesylate anion with its potential genotoxic risks, the total toxicity of the drug product could be decreased. The amorphous ILs proved adequate stability under forcing conditions and there was no recrystallization of the free base observed. The amorphous character of the ILs caused an increased amount of water vapour sorption which can be compensated by special packaging materials. Taken together, the presentation of imatinib as an IL is intended for oral administration as a tablet and can cause a reduction of dose because of the increased solubility. Therefore, the occurrence of side effects can be reduced as compared to Gleevec®. If there is actually an increased bioavailability to observe, has to be proved by the execution of animal trials.
The novel NOX inhibitor VAS3947 is intended for the treatment of endothelial dysfunctions causing diseases like heart failure and stroke. The compounds poor aqueous solubility hindered further clinical development so far and make the drug candidate to remain in a very early stage of the drug development process. Therefore, different formulation concepts were evaluated in this study:
An amorphous solid dispersion prepared from VAS3947 and Eudragit® L100 by means of spray drying was able to increase the dissolution rate and solubility of the compound significantly, but with the accomplished kinetic solubility being in the low µM range it is not possible to reach therapeutic plasma concentrations.
In contrast, the incorporation into cyclodextrins resulted in an 760-fold increased solubility. Different cyclodextrins were evaluated. Especially the lipophilic derivatives of the β-cyclodextrin showed to be the most adequate excipients. The incorporation of the API into the cyclodextrin cavity was proved by means of NMR spectroscopy. Additionally, a formulation of VAS3947 and hydroxypropyl-β-cyclodextrin was prepared. This formulation is intended for the intravenous application during animal trials, which have to be conducted to get to know the pharmacokinetics of VAS3947. This formulation reached a concentration of 1 mg/mL spending striking protection of VAS3947 against degradation.
Presentation of VAS3947 as a microemulsion system led also to increase the aqueous solubility of the compound, but not in the same extent as the cyclodextrin formulation. Beside the formulation development a physicochemical characterization was performed to get to know important parameters such as log P and pKa values of VAS3947. An HPLC method was developed and validated to analyse the extent of solubility improvement.
A major issue of the compound VAS3947 and all related triazolopyrimidine derivatives, developed by Vasopharm GmbH, is the insufficient chemical stability because of presence of a hemiaminal moiety in the chemical structure. Stability investigations and an extensive biopharmaceutical characterization confirm the hindering of further clinical development by insufficient drug stability and high cytotoxicity. Poor aqueous solubility is an additional disadvantage which can be handled by a concerted formulation development.
Epicardium-derived cells (EPDC) and atrial stromal cells (ASC) display cardio-regenerative potential, but the molecular details are still unexplored. Signals which induce activation, migration and differentiation of these cells are largely unknown. Here we have isolated rat ventricular EPDC and rat/human ASC and performed genetic and proteomic profiling. EPDC and ASC expressed epicardial/mesenchymal markers (WT-1, Tbx18, CD73,CD90, CD44, CD105), cardiac markers (Gata4, Tbx5, troponin T) and also contained phosphocreatine. We used cell surface biotinylation to isolate plasma membrane proteins of rEPDC and hASC, Nano-liquid chromatography with subsequent mass spectrometry and bioinformatics analysis identified 396 rat and 239 human plasma membrane proteins with 149 overlapping proteins. Functional GO-term analysis revealed several significantly enriched categories related to extracellular matrix (ECM), cell migration/differentiation, immunology or angiogenesis. We identified receptors for ephrin and growth factors (IGF, PDGF, EGF, anthrax toxin) known to be involved in cardiac repair and regeneration. Functional category enrichment identified clusters around integrins, PI3K/Akt-signaling and various cardiomyopathies. Our study indicates that EPDC and ASC have a similar molecular phenotype related to cardiac healing/regeneration. The cell surface proteome repository will help to further unravel the molecular details of their cardio-regenerative potential and their role in cardiac diseases.
Blazars like Markarian 421 or Markarian 501 are active galactic nuclei (AGN), with their jets orientated towards the observer. They are among the brightest objects in the very high energy (VHE) gamma ray regime (>100 GeV). Their emitted gamma-ray fluxes are extremely variable, with changing activity levels on timescales between minutes, months, and even years. Several questions are part of the current research, such as the question of the emission regions or the engine of the AGN and the particle acceleration. A dedicated longterm monitoring program is necessary to investigate the properties of blazars in detail. A densely sampled and unbiased light curve allows for observation of both high and low states of the sources, and the combination with multi-wavelength observation could contribute to the answer of several questions mentioned above. FACT (First G-APD Cherenkov Telescope) is the first operational telescope using silicon photomultiplier (SiPM, also known as Geigermode—Avalanche Photo Diode, G-APD) as photon detectors. SiPM have a very homogenous and stable longterm performance, and allow operation even during full moon without any filter, leading to a maximal duty cycle for an Imaging Air Cherenkov Telescope (IACT). Hence, FACT is an ideal device for such a longterm monitoring of bright blazars. A small set of sources (e.g., Markarian 421, Markarian 501, 1ES 1959+650, and 1ES 2344+51.4) is currently being monitored. In this contribution, the FACT telescope and the concept of longterm monitoring of bright blazars will be introduced. The results of the monitoring program will be shown, and the advantages of densely sampled and unbiased light curves will be discussed.
Many pathogenic bacteria utilize specialized secretion systems to deliver proteins called effectors into eukaryotic cells for manipulation of host pathways. The vast majority of known effector targets are host proteins, whereas a potential targeting of host nucleic acids remains little explored. There is only one family of effectors known to target DNA directly, and effectors binding host RNA are unknown. Here, we take a two-pronged approach to search for RNA-binding effectors, combining biocomputational prediction of RNA-binding domains (RBDs) in a newly assembled comprehensive dataset of bacterial secreted proteins, and experimental screening for RNA binding in mammalian cells. Only a small subset of effectors were predicted to carry an RBD, indicating that if RNA targeting was common, it would likely involve new types of RBDs. Our experimental evaluation of effectors with predicted RBDs further argues for a general paucity of RNA binding activities amongst bacterial effectors. We obtained evidence that PipB2 and Lpg2844, effector proteins of Salmonella and Legionella species, respectively, may harbor novel biochemical activities. Our study presenting the first systematic evaluation of the RNA-targeting potential of bacterial effectors offers a basis for discussion of whether or not host RNA is a prominent target of secreted bacterial proteins.
Site Directed Immobilization of BMP-2: Two Approaches for the Production of Osteoinductive Scaffolds
(2017)
Bone fractures typically heal without surgical intervention. However, pathological situations exist which impede the healing process resulting in so-called non-union fractures. Such fractures are nowadays treated with scaffold material being introduced into the defect area. These scaffolds can be doped with osteogenic factors, such as bone morphogenetic protein (BMP)2. BMP2 belongs to the most osteogenic growth factors known to date. Its medical use, efficiency and safety have been approved by FDA for certain applications. Currently, BMP2 is distributed with a stabilizing scaffold, which is simply soaked with the growth factor. Due to fast release kinetics supraphysiological high doses of BMP2 are required which are causally associated with severe side effects observed in certain applications being most harmful in the area of the cervical spine. These side-effects include inflammation, swelling and breathing problems, leading to disastrous consequences or secondary surgical interventions. Since it could be shown that a retardation of BMP2 release from the scaffold resulted in superior bone forming properties in vivo, it seems obvious to further reduce this release to a minimum. This can be achieved by covalent coupling which in the past was already elaborated using mainly classical EDC/NHS chemistry. Using this technique coupling of the protein occurs non-site-directedly leading mainly to an unpredictable product outcome with variable osteogenic activities. In order to improve the reproducibility of scaffold functionalization by BMP2 we created variants one of which contains a unique unnatural amino acid substitution within the mature polypeptide sequence (BMP2-K3Plk) and another, BMP2-A2C, in which an N-terminal alanine has been substituted by cysteine. These modifications enable site-specific and covalent immobilization of BMP2 e.g. onto polymeric beads. Both proteins were expressed in E. coli, renatured and purified by cation-exchange chromatography. Both variants were extensively analyzed in terms of purity and biological activity which was tested by in vitro interaction analyses as well as in cell based assays. Both proteins could be successfully coupled to polymeric beads. The different BMP2 functionalized beads were shown to interact with the ectodomain of the type I receptor BMPR-IA in vitro indicating that the biological activity of both BMP2 variants retained upon coupling. Both functionalized beads induced osteogenic differentiation C2C12 cells but only of those cells which have been in close contact to the particular beads. This strongly indicates that the BMP2 variant are indeed covalently coupled and not just adsorbed.
We claim that we have developed a system for a site-specific and covalent immobilization of BMP-2 onto solid scaffolds, potentially eliminating the necessity of high-dose scaffold loading. Since immobilized proteins are protected from removal by extracellular fluids, their activities now rely mainly on the half-life of the used scaffold and the rate of proteolytic degradation. Assuming that due to prolonged times much lower loading capacities might be required we propose that the immobilization strategy employed in this work may be further refined and optimized to replace the currently used BMP2-containing medical products.
We theoretically investigate the propagation of heat currents in a three-terminal quantum dot engine. Electron–electron interactions introduce state-dependent processes which can be resolved by energy-dependent tunneling rates. We identify the relevant transitions which define the operation of the system as a thermal transistor or a thermal diode. In the former case, thermal-induced charge fluctuations in the gate dot modify the thermal currents in the conductor with suppressed heat injection, resulting in huge amplification factors and the possible gating with arbitrarily low energy cost. In the latter case, enhanced correlations of the state-selective tunneling transitions redistribute heat flows giving high rectification coefficients and the unexpected cooling of one conductor terminal by heating the other one. We propose quantum dot arrays as a possible way to achieve the extreme tunneling asymmetries required for the different operations.
A system-wide understanding of cellular function requires knowledge of all functional interactions between the expressed proteins. The STRING database aims to collect and integrate this information, by consolidating known and predicted protein–protein association data for a large number of organisms. The associations in STRING include direct (physical) interactions, as well as indirect (functional) interactions, as long as both are specific and biologically meaningful. Apart from collecting and reassessing available experimental data on protein–protein interactions, and importing known pathways and protein complexes from curated databases, interaction predictions are derived from the following sources: (i) systematic co-expression analysis, (ii) detection of shared selective signals across genomes, (iii) automated text-mining of the scientific literature and (iv) computational transfer of interaction knowledge between organisms based on gene orthology. In the latest version 10.5 of STRING, the biggest changes are concerned with data dissemination: the web frontend has been completely redesigned to reduce dependency on outdated browser technologies, and the database can now also be queried from inside the popular Cytoscape software framework. Further improvements include automated background analysis of user inputs for functional enrichments, and streamlined download options. The STRING resource is available online, at http://string-db.org/.
The issue of quantum mechanical coupling between a semiconductor quantum dot and a quantum well is studied in two families of GaAs- and InP- based structures at cryogenic temperatures. It is shown that by tuning the quantum well parameters one can strongly disturb the 0D-character of the coupled system ground state, initially located in a dot. The out-coupling of either an electron or a hole state from the quantum dot confining potential is viewed by a significant elongation of the photoluminescence decay time constant. Band structure calculations show that in the GaAs-based coupled system at its ground state a hole remains isolated in the dot, whereas an electron gets delocalized towards the quantum well. The opposite picture is built for the ground state of a coupled system based on InP.
Analysis of host microRNA function uncovers a role for miR-29b-2-5p in Shigella capture by filopodia
(2017)
MicroRNAs play an important role in the interplay between bacterial pathogens and host cells, participating as host defense mechanisms, as well as exploited by bacteria to subvert host cellular functions. Here, we show that microRNAs modulate infection by Shigella flexneri, a major causative agent of bacillary dysentery in humans. Specifically, we characterize the dual regulatory role of miR-29b-2-5p during infection, showing that this microRNA strongly favors Shigella infection by promoting both bacterial binding to host cells and intracellular replication. Using a combination of transcriptome analysis and targeted high-content RNAi screening, we identify UNC5C as a direct target of miR-29b-2-5p and show its pivotal role in the modulation of Shigella binding to host cells. MiR-29b-2-5p, through repression of UNC5C, strongly enhances filopodia formation thus increasing Shigella capture and promoting bacterial invasion. The increase of filopodia formation mediated by miR-29b-2-5p is dependent on RhoF and Cdc42 Rho-GTPases. Interestingly, the levels of miR-29b-2-5p, but not of other mature microRNAs from the same precursor, are decreased upon Shigella replication at late times post-infection, through degradation of the mature microRNA by the exonuclease PNPT1. While the relatively high basal levels of miR-29b-2-5p at the start of infection ensure efficient Shigella capture by host cell filopodia, dampening of miR-29b-2-5p levels later during infection may constitute a bacterial strategy to favor a balanced intracellular replication to avoid premature cell death and favor dissemination to neighboring cells, or alternatively, part of the host response to counteract Shigella infection. Overall, these findings reveal a previously unappreciated role of microRNAs, and in particular miR-29b-2-5p, in the interaction of Shigella with host cells.
Microcavity exciton polaritons are promising candidates to build a new generation of highly nonlinear and integrated optoelectronic devices. Such devices range from novel coherent light emitters to reconfigurable potential landscapes for electro-optical polariton-lattice based quantum simulators as well as building blocks of optical logic architectures. Especially for the latter, the strongly interacting nature of the light-matter hybrid particles has been used to facilitate fast and efficient switching of light by light, something which is very hard to achieve with weakly interacting photons. We demonstrate here that polariton transistor switches can be fully integrated in electro-optical schemes by implementing a one-dimensional polariton channel which is operated by an electrical gate rather than by a control laser beam. The operation of the device, which is the polariton equivalent to a field-effect transistor, relies on combining electro-optical potential landscape engineering with local exciton ionization to control the scattering dynamics underneath the gate. We furthermore demonstrate that our device has a region of negative differential resistance and features a completely new way to create bistable behavior.
This paper proposes an attitude determination system for small Unmanned Aerial Vehicles (UAV) with a weight limit of 5 kg and a small footprint of 0.5m x 0.5 m. The system is realized by coupling single-frequency Global Positioning System (GPS) code and carrier-phase measurements with the data acquired from a Micro-Electro-Mechanical System (MEMS) Inertial Measurement Unit (IMU) using consumer-grade Components-Off-The-Shelf (COTS) only. The sensor fusion is accomplished using two Extended Kalman Filters (EKF) that are coupled by exchanging information about the currently estimated baseline. With a baseline of 48 cm, the static heading accuracy of the proposed system is comparable to the one of a commercial single-frequency GPS heading system with an accuracy of approximately 0.25°/m. Flight testing shows that the proposed system is able to obtain a reliable and stable GPS heading estimation without an aiding magnetometer.
Platelets are continuously produced from megakaryocytes (MK) in the bone marrow by a cytoskeleton-driven process of which the molecular regulation is not fully understood.
As revealed in this thesis, MK/ platelet-specific Profilin1 (Pfn1) deficiency results in micro- thrombocytopenia, a hallmark of the Wiskott-Aldrich syndrome (WAS) in humans, due to accelerated platelet turnover and premature platelet release into the bone marrow. Both Pfn1-deficient mouse platelets and platelets isolated from WAS patients contained abnormally organized and hyper-stable microtubules. These results reveal an unexpected function of Pfn1 as a regulator of microtubule organization and point to a previously unrecognized mechanism underlying the platelet formation defect in WAS patients.
In contrast, Twinfilin2a (Twf2a) was established as a central regulator of platelet reactivity and turnover. Twf2a-deficient mice revealed an age-dependent macrothrombocytopenia that could be explained by a markedly decreased platelet half-life, likely due to the pronounced hyper-reactivity of \(Twf2a^{-/-}\) platelets. The latter was characterized by sustained integrin acti- vation and thrombin generation in vitro that translated into accelerated thrombus formation in vivo. To further elucidate mechanisms of integrin activation, Rap1-GTP-interacting adaptor molecule (RIAM)-null mice were generated. Despite the proposed critical role of RIAM for platelet integrin activation, no alterations in this process could be found and it was concluded that RIAM is dispensable for the activation of β1 and β3 integrins, at least in platelets. These findings change the current mechanistic understanding of platelet integrin activation.
Outside-in signaling by integrins and other surface receptors was supposed to regulate MK migration, but also the temporal and spatial formation of proplatelet protrusions. In this the- sis, phospholipase D (PLD) was revealed as critical regulator of actin dynamics and podo- some formation in MKs. Hence, the unaltered platelet counts and production in \(Pld1/2^{-/-}\) mice and the absence of a premature platelet release in the bone marrow of \(Itga2^{-/-}\) mice question the role of podosomes in platelet production and raise the need to reconsider the proposed inhibitory signaling by α2β1 integrins on proplatelet formation.
Non-muscle myosin IIA (NMMIIA) has been implicated as a downstream effector of the in- hibitory signals transmitted via α2β1 integrins. Besides Rho-GTPase signaling, also \(Mg^{2+}\) and transient receptor potential melastatin-like 7 (TRPM7) channel α-kinase are known regulators of NMMIIA activity. In this thesis, TRPM7 was identified as major regulator of \(Mg^{2+}\) homeostasis in MKs and platelets. Furthermore, decreased \([Mg^{2+}]_i\) led to deregulated NMMIIA activity and altered cytoskeletal dynamics that impaired thrombopoiesis and resulted in macrothrombocytopenia in humans and mice.
New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{−1}\)·s\(^{−1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{−1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging.
Background:
There is a paucity of studies examining the safety of venom immunotherapy (VIT) in children. We aimed to assess the incidence of anaphylactic side effects during rush VIT in a cohort of pediatric patients and adult controls.
Methods:
72 consecutive cycles of VIT-buildup in 71 children/adolescents aged 7–17 years were retrospectively evaluated and compared to an adult control group (n = 981) with regard to baseline parameters (sex, causative venom, severity of index sting reaction, results of allergy testing, comorbidities) and the incidence of anaphylactic adverse reactions.
Results:
Compared to adults, severe index sting-induced anaphylaxis was significantly less common in children (P = .001). Children were more likely to suffer from bee venom allergy (P < .001) and showed higher levels of bee venom-specific IgE (P = .013), but lower serum tryptase concentrations (P = .014). The overall rate of VIT-induced anaphylactic reactions was higher in children than in adults (6.9% vs 2.5%, P = .046 by univariate analysis). In the final binary logistic regression model, however, only bee VIT (P = .039; odds ratio 2.25; confidence interval 1.04–4.87) and 5-day compared to 3-day buildup protocols (P = .011; odds ratio 2.64; confidence interval 1.25–5.57) were associated with an increased risk of treatment-induced anaphylaxis. All pediatric patients finally reached and tolerated the target maintenance dose of 100 µg.
Conclusions:
The higher anaphylactic reaction rate observed in pediatric patients may be attributed to a greater prevalence of bee venom allergy. VIT-induced anaphylaxis in children is usually mild and does not affect further updosing and maintenance of VIT.
This dissertation investigates selected causes and effects of worker mobility between firms in three empirical studies for Germany. Chapter 2 investigates the productivity effects of worker inflows to manufacturing establishments, distinguishing inflows by their previous employers’ wage level, as a proxy for productivity. The chapter is motivated by several empirical studies which find that worker inflows from more productive or higher-paying firms increase hiring firms’ productivity. The analyses in chapter 2 are based on a unique linked employer-employee data set. The findings indicate that inflows from higher-paying establishments do not increase hiring establishments’ productivity, but inflows from lower-paying establishments do. Further analyses suggest that this effect is due to a positive selectivity of such inflows from their sending establishments. These findings can be interpreted as evidence of a reallocation process by which the best employees of lower-paying establishments become hired by higher-paying establishments. This process reflects the assortative pattern of worker mobility in Germany documented by Card et al. (2013) for the past decades. The chapter thus contributes to the literature by linking establishment-level productivity analysis to the assortative pattern of inter-firm worker mobility, thereby providing a micro-foundation for the latter.
Chapter 3 focuses on a positive selection of workers moving between firms from another, more specific perspective. The analysis focuses on the importance of regional labor market competition for establishments’ apprentice training and poaching of apprenticeship completers. Previous studies have found that firms provide less training if they are located in regions with strong labor market competition. This finding is usually interpreted as evidence of a higher risk of poaching in these regions. Yet, there is no direct evidence that regional competition is positively correlated with poaching. Building on a recently established approach to ex-post identify poaching of apprenticeship completers, this chapter is the first to directly investigate the correlation between regional labor market competition and poaching. Using German administrative data, it is found that competition indeed increases training establishments’ probability of becoming poaching victims. However, poaching victims do not change their apprenticeship training activity in reaction to poaching. Instead, the findings indicate that the lower training activity in competitive regions can be attributed to lower retention rates, as well as a less adverse selection and lower labor and hiring costs of apprenticeship completers hired from rivals.
Chapter 4 investigates the effects of local broadband internet availability on establishment-level employment growth. The analysis uses data for Germany in the years 2005-2009, when broadband was introduced in rural regions of Western Germany and in large parts of Eastern Germany. Technical frictions in broadband rollout are exploited to obtain exogenous variation in local broadband availability. The results suggest that broadband expansion had a positive effect on employment growth in the Western German service sector and a negative effect in Western German manufacturing, suggesting that broadband expansion has accelerated the reallocation of workers from manufacturing to services. Furthermore, this pattern of results is driven by pronounced positive effects in knowledge- and computer-intensive industries, suggesting that it is the actual use of broadband in the production process that leads to complementary hiring, respectively a slowdown of employment growth, in the respective sectors. For Eastern Germany, no significant employment growth effects are found.
This is a pilot study that examined the effect of cell-phone conversation on cognition using a continuous multitasking paradigm. Current theorizing argues that phone conversation affects behavior (e.g., driving) by interfering at a level of cognitive processes (not peripheral activity) and by implying an attentional-failure account. Within the framework of an intermittent spare–utilized capacity threading model, we examined the effect of aspects of (secondary-task) phone conversation on (primary-task) continuous arithmetic performance, asking whether phone use makes components of automatic and controlled information-processing (i.e., easy vs. hard mental arithmetic) run more slowly, or alternatively, makes processing run less reliably albeit with the same processing speed. The results can be summarized as follows: While neither expecting a text message nor expecting an impending phone call had any detrimental effects on performance, active phone conversation was clearly detrimental to primary-task performance. Crucially, the decrement imposed by secondary-task (conversation) was not due to a constant slowdown but is better be characterized by an occasional breakdown of information processing, which differentially affected automatic and controlled components of primary-task processing. In conclusion, these findings support the notion that phone conversation makes individuals not constantly slower but more vulnerable to commit attention failure, and in this way, hampers stability of (primary-task) information processing.
Bee pollination increases yield quantity and quality of cash crops in Burkina Faso, West Africa
(2017)
Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders’ production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.
Background
Artificial rearing of honey bee larvae is an established method which enables to fully standardize the rearing environment and to manipulate the supplied diet to the brood. However, there are no studies which compare learning performance or neuroanatomic differences of artificially-reared (in-lab) bees in comparison with their in-hive reared counterparts.
Methods
Here we tested how different quantities of food during larval development affect body size, brain morphology and learning ability of adult honey bees. We used in-lab rearing to be able to manipulate the total quantity of food consumed during larval development. After hatching, a subset of the bees was taken for which we made 3D reconstructions of the brains using confocal laser-scanning microscopy. Learning ability and memory formation of the remaining bees was tested in a differential olfactory conditioning experiment. Finally, we evaluated how bees reared with different quantities of artificial diet compared to in-hive reared bees.
Results
Thorax and head size of in-lab reared honey bees, when fed the standard diet of 160 µl or less, were slightly smaller than hive bees. The brain structure analyses showed that artificially reared bees had smaller mushroom body (MB) lateral calyces than their in-hive counterparts, independently of the quantity of food they received. However, they showed the same total brain size and the same associative learning ability as in-hive reared bees. In terms of mid-term memory, but not early long-term memory, they performed even better than the in-hive control.
Discussion
We have demonstrated that bees that are reared artificially (according to the Aupinel protocol) and kept in lab-conditions perform the same or even better than their in-hive sisters in an olfactory conditioning experiment even though their lateral calyces were consistently smaller at emergence. The applied combination of experimental manipulation during the larval phase plus subsequent behavioral and neuro-anatomic analyses is a powerful tool for basic and applied honey bee research.
Drug delivery of therapeutic gases – strategies for controlled and local delivery of carbon monoxide
(2017)
The isoenzyme heme oxygenase 1 (HO-1) is a key element for maintaining cellular homeostasis. Upregulated in response to cellular stress, the HO-1 degrades heme into carbon monoxide (CO), biliverdin, and Fe2+. By means of a local cell-protective feedback loop the enzyme triggers numerous effects including anti-oxidative, anti-apoptotic, and anti-inflammatory events associated with complex signalling patterns which are largely orchestrated by CO. Various approaches to mimic this physiological HO-1 / CO system aiming for a treatment of medical conditions have been described [1]. These preclinical studies commonly applied CO systemically via (i) inhalation or (ii) using CO-Releasing Molecules (CORMs) [2]. The clinical use of these approaches, however, is challenged by a lack of practicability and substantial safety issues associated with the toxicity of high systemic doses of CO that are required for triggering therapeutic effects. Therefore, one rational of this thesis is to describe and evaluate strategies for the local delivery of CO aiming for safe and effective CO therapeutics of tomorrow.
In mammals, megakaryocytes (MKs) in the bone marrow (BM) produce blood platelets, required for hemostasis and thrombosis. MKs originate from hematopoietic stem cells and are thought to migrate from an endosteal niche towards the vascular sinusoids during their maturation. Through imaging of MKs in the intact BM, here we show that MKs can be found within the entire BM, without a bias towards bone-distant regions. By combining in vivo two-photon microscopy and in situ light-sheet fluorescence microscopy with computational simulations, we reveal surprisingly slow MK migration, limited intervascular space, and a vessel-biased MK pool. These data challenge the current thrombopoiesis model of MK migration and support a modified model, where MKs at sinusoids are replenished by sinusoidal precursors rather than cells from a distant periostic niche. As MKs do not need to migrate to reach the vessel, therapies to increase MK numbers might be sufficient to raise platelet counts.
In this work, multi-particle quantum optimal control problems are studied in the framework of time-dependent density functional theory (TDDFT).
Quantum control problems are of great importance in both fundamental research and application of atomic and molecular systems. Typical applications are laser induced chemical reactions, nuclear magnetic resonance experiments, and quantum computing.
Theoretically, the problem of how to describe a non-relativistic system of multiple particles is solved by the Schrödinger equation (SE). However, due to the exponential increase in numerical complexity with the number of particles, it is impossible to directly solve the Schrödinger equation for large systems of interest. An efficient and successful approach to overcome this difficulty is the framework of TDDFT and the use of the time-dependent Kohn-Sham (TDKS) equations therein.
This is done by replacing the multi-particle SE with a set of nonlinear single-particle Schrödinger equations that are coupled through an additional potential.
Despite the fact that TDDFT is widely used for physical and quantum chemical calculation and software packages for its use are readily available, its mathematical foundation is still under active development and even fundamental issues remain unproven today.
The main purpose of this thesis is to provide a consistent and rigorous setting for the TDKS equations and of the related optimal control problems.
In the first part of the thesis, the framework of density functional theory (DFT) and TDDFT are introduced. This includes a detailed presentation of the different functional sets forming DFT. Furthermore, the known equivalence of the TDKS system to the original SE problem is further discussed.
To implement the TDDFT framework for multi-particle computations, the TDKS equations provide one of the most successful approaches nowadays. However, only few mathematical results concerning these equations are available and these results do not cover all issues that arise in the formulation of optimal control problems governed by the TDKS model.
It is the purpose of the second part of this thesis to address these issues such as higher regularity of TDKS solutions and the case of weaker requirements on external (control) potentials that are instrumental for the formulation of well-posed TDKS control problems. For this purpose, in this work, existence and uniqueness of TDKS solutions are investigated in the Galerkin framework and using energy estimates for the nonlinear TDKS equations.
In the third part of this thesis, optimal control problems governed by the TDKS model are formulated and investigated. For this purpose, relevant cost functionals that model the purpose of the control are discussed.
Henceforth, TDKS control problems result from the requirement of optimising the given cost functionals subject to the differential constraint given by the TDKS equations. The analysis of these problems is novel and represents one of the main contributions of the present thesis.
In particular, existence of minimizers is proved and their characterization by TDKS optimality systems is discussed in detail.
To this end, Fréchet differentiability of the TDKS model and of the cost functionals is addressed considering \(H^1\) cost of the control.
This part is concluded by deriving the reduced gradient in the \(L^2\) and \(H^1\) inner product.
While the \(L^2\) optimization is widespread in the literature, the choice of the \(H^1\) gradient is motivated in this work by theoretical consideration and by resulting numerical advantages.
The last part of the thesis is devoted to the numerical approximation of the TDKS optimality systems and to their solution by gradient-based optimization techniques.
For the former purpose, Strang time-splitting pseudo-spectral schemes are discussed including a review of some recent theoretical estimates for these schemes and a numerical validation of these estimates.
For the latter purpose, nonlinear (projected) conjugate gradient methods are implemented and are used to validate the theoretical analysis of this thesis with results of numerical experiments with different cost functional settings.
The contact of hot melt with liquid water - called Molten Fuel Coolant Interaction (MFCI) - can result in vivid explosions. Such explosions can occur in different scenarios: in steel or powerplants but also in volcanoes. Because of the possible dramatic consequences of such explosions an investigation of the explosion process is necessary.
Fundamental basics of this process are already discovered and explained, such as the frame conditions for these explosions. It has been shown that energy transfer during an MFCI-process can be very high because of the transfer of thermal energy caused by positive feedback mechanisms.
Up to now the influence of several varying parameters on the energy transfer and the explosions is not yet investigated sufficiently. An important parameter is the melt temperature, because the amount of possibly transferable energy depends on it. The investigation of this influence is the main aim of this work. Therefor metallic tin melt was used, because of its nearly constant thermal material properties in a wide temperature range. With tin melt research in the temperature range from 400 °C up to 1000 °C are
possible.
One important result is the lower temperature limit for vapor film stability in the experiments. For low melt temperatures up to about 600 °C the vapor film is so unstable that it already can collapse before the mechanical trigger. As expected the transferred thermal energy all in all increases with higher temperatures. Although this effect sometimes is superposed by other influences such as the premix of melt and water, the result is confirmed after a consequent filtering of the remaining influences. This trend is not only recognizable in the amount of transferred energy, but also in the fragmentation of melt or the vaporizing water. But also the other influences on MFCI-explosions showed interesting results in the frame of this work. To perform the experiments the installation and preparation of the experimental Setup in the laboratory were necessary.
In order to compare the results to volcanism and to get a better investigation of the brittle fragmentation
of melt additional runs with magmatic melt were made. In the results the thermal power during energy transfer could be estimated. Furthermore the model of “cooling fragments “ could be usefully applied.
Enterprise applications in virtualized data centers are often subject to time-varying workloads, i.e., the load intensity and request mix change over time, due to seasonal patterns and trends, or unpredictable bursts in user requests. Varying workloads result in frequently changing resource demands to the underlying hardware infrastructure. Virtualization technologies enable sharing and on-demand allocation of hardware resources between multiple applications. In this context, the resource allocations to virtualized applications should be continuously adapted in an elastic fashion, so that "at each point in time the available resources match the current demand as closely as possible" (Herbst el al., 2013). Autonomic approaches to resource management promise significant increases in resource efficiency while avoiding violations of performance and availability requirements during peak workloads.
Traditional approaches for autonomic resource management use threshold-based rules (e.g., Amazon EC2) that execute pre-defined reconfiguration actions when a metric reaches a certain threshold (e.g., high resource utilization or load imbalance). However, many business-critical applications are subject to Service-Level-Objectives defined on an application performance metric (e.g., response time or throughput). To determine thresholds so that the end-to-end application SLO is fulfilled poses a major challenge due to the complex relationship between the resource allocation to an application and the application performance. Furthermore, threshold-based approaches are inherently prone to an oscillating behavior resulting in unnecessary reconfigurations.
In order to overcome the deficiencies of threshold-based
approaches and enable a fully automated approach to dynamically control the resource allocations of virtualized applications, model-based approaches are required that can predict the impact of a reconfiguration on the application performance in advance. However, existing model-based approaches are severely limited in their learning capabilities. They either require complete performance models of the application as input, or use a pre-identified model structure and only learn certain model parameters from empirical data at run-time. The former requires high manual efforts and deep system knowledge to create the performance models. The latter does not provide the flexibility to capture the specifics of complex and heterogeneous system architectures.
This thesis presents a self-aware approach to the resource management in virtualized data centers. In this context, self-aware means that it automatically learns performance models of the application and the virtualized infrastructure and reasons based on these models to autonomically adapt the resource allocations in accordance with given application SLOs. Learning a performance model requires the extraction of the model structure representing the system architecture as well as the estimation of model parameters, such as resource demands. The estimation of resource demands is a key challenge as they cannot be observed directly in most systems.
The major scientific contributions of this thesis are:
- A reference architecture for online model learning in virtualized systems. Our reference architecture is based on a set of model extraction agents. Each agent focuses on specific tasks to automatically create and update model skeletons capturing its local knowledge of the system and collaborates with other agents to extract the structural parts of a global performance model of the system. We define different agent roles in the reference architecture and propose a model-based collaboration mechanism for the agents. The agents may be bundled within virtual appliances and may be tailored to include knowledge about the software stack deployed in a specific virtual appliance.
- An online method for the statistical estimation of resource demands. For a given request processed by an application, the resource time consumed for a specified resource within the system (e.g., CPU or I/O device), referred to as resource demand, is the total average time the resource is busy processing the request. A request could be any unit of work (e.g., web page request, database transaction, batch job) processed by the system. We provide a systematization of existing statistical approaches to resource demand estimation and conduct an extensive experimental comparison to evaluate the accuracy of these approaches. We propose a novel method to automatically select estimation approaches and demonstrate that it increases the robustness and accuracy of the estimated resource demands significantly.
- Model-based controllers for autonomic vertical scaling of virtualized applications. We design two controllers based on online model-based reasoning techniques in order to vertically scale applications at run-time in accordance with application SLOs. The controllers exploit the knowledge from the automatically extracted performance models when determining necessary reconfigurations. The first controller adds and removes virtual CPUs to an application depending on the current demand. It uses a layered performance model to also consider the physical resource contention when determining the required resources. The second controller adapts the resource allocations proactively to ensure the availability of the application during workload peaks and avoid reconfiguration during phases of high workload.
We demonstrate the applicability of our approach in current virtualized environments and show its effectiveness leading to significant increases in resource efficiency and improvements of the application performance and availability under time-varying workloads. The evaluation of our approach is based on two case studies representative of widely used enterprise applications in virtualized data centers. In our case studies, we were able to reduce the amount of required CPU resources by up to 23% and the number of reconfigurations by up to 95% compared to a rule-based approach while ensuring full compliance with application SLO. Furthermore, using workload forecasting techniques we were able to schedule expensive reconfigurations (e.g., changes to the memory size) during phases of load load and thus were able to reduce their impact on application availability by over 80% while significantly improving application performance compared to a reactive controller. The methods and techniques for resource demand estimation and vertical application scaling were developed and evaluated in close collaboration with VMware and Google.
The effects of circuit-like functional high-intensity training (Circuit\(_{HIIT}\)) alone or in combination with high-volume low-intensity exercise (Circuit\(_{combined}\)) on selected cardio-respiratory and metabolic parameters, body composition, functional strength and the quality of life of overweight women were compared. In this single-center, two-armed randomized, controlled study, overweight women performed 9-weeks (3 sessions·wk\(^{−1}\)) of either Circuit\(_{HIIT}\) (n = 11), or Circuit\(_{combined}\) (n = 8). Peak oxygen uptake and perception of physical pain were increased to a greater extent (p < 0.05) by Circuit\(_{HIIT}\), whereas Circuit\(_{combined}\) improved perception of general health more (p < 0.05). Both interventions lowered body mass, body-mass-index, waist-to-hip ratio, fat mass, and enhanced fat-free mass; decreased ratings of perceived exertion during submaximal treadmill running; improved the numbers of push-ups, burpees, one-legged squats, and 30-s skipping performed, as well as the height of counter-movement jumps; and improved physical and social functioning, role of physical limitations, vitality, role of emotional limitations, and mental health to a similar extent (all p < 0.05). Either forms of these multi-stimulating, circuit-like, multiple-joint training can be employed to improve body composition, selected variables of functional strength, and certain dimensions of quality of life in overweight women. However, Circuit\(_{HIIT}\) improves peak oxygen uptake to a greater extent, but with more perception of pain, whereas Circuit\(_{Combined}\) results in better perception of general health.
The aim of this pilot study was to analyze the off-training physical activity (PA) profile in national elite German U23 rowers during 31 days of their preparation period. The hours spent in each PA category (i.e., sedentary: <1.5 metabolic equivalents (MET); light physical activity: 1.5–3 MET; moderate physical activity: 3–6 MET and vigorous intense physical activity: >6 MET) were calculated for every valid day (i.e., >480 min of wear time). The off-training PA during 21 weekdays and 10 weekend days of the final 11-week preparation period was assessed by the wrist-worn multisensory device Microsoft Band II (MSBII). A total of 11 rowers provided valid data (i.e., >480 min/day) for 11.6 week days and 4.8 weekend days during the 31 days observation period. The average sedentary time was 11.63 ± 1.25 h per day during the week and 12.49 ± 1.10 h per day on the weekend, with a tendency to be higher on the weekend compared to weekdays (p = 0.06; d = 0.73). The average time in light, moderate and vigorous PA during the weekdays was 1.27 ± 1.15, 0.76 ± 0.37, 0.51 ± 0.44 h per day, and 0.67 ± 0.43, 0.59 ± 0.37, 0.53 ± 0.32 h per weekend day. Light physical activity was higher during weekdays compared to the weekend (p = 0.04; d = 0.69). Based on our pilot study of 11 national elite rowers we conclude that rowers display a considerable sedentary off-training behavior of more than 11.5 h/day.
This work is concerned with the syntheses and photophysical properties of para-xylylene bridged macrocycles nPBI with ring sizes from two to nine PBI units, as well as the complexation of polycyclic aromatic guest compounds.
With a reduced but substantial fluorescence quantum yield of 21% (in CHCl3) the free host 2PBI(4-tBu)4 can be used as a dual fluorescence probe. Upon encapsulation of rather electron-poor guests the fluorescence quenching interactions between the chromophores are prevented, leading to a significant fluorescence enhancement to > 90% (“turn-on”). On the other hand, the addition of electron-rich guest molecules induces an electron transfer from the guest to the electron-poor PBI chromophores and thus quenches the fluorescence entirely (“turn-off”). The photophysical properties of the host-guest complexes were studied by transient absorption spectroscopy. These measurements revealed that the charge transfer between guest and 2PBI(4-tBu)4 occurs in the “normal region” of the Marcus-parabola with the fastest charge separation rate for perylene. In contrast, the charge recombination back to the PBI ground state lies far in the “inverted region” of the Marcus-parabola.
Beside complexation of planar aromatic hydrocarbons into the cavity of the cyclophanes an encapsulation of fullerene into the cyclic trimer 3PBI(4-tBu)4 was observed. 3PBI(4-tBu)4 provides a tube-like structure in which the PBI subunits represent the walls of those tubes. The cavity has the optimal size for hosting fullerenes, with C70 fitting better than C60 and a binding constant that is higher by a factor of 10. TA spectroscopy in toluene that was performed on the C60@3PBI(4-tBu)4 complex revealed two energy transfer processes. The first one comes from the excited PBI to the fullerene, which subsequently populates the triplet state. From the fullerene triplet state a second energy transfer occurs back to the PBI to generate the PBI triplet state.
In all cycles that were studied by TA spectroscopy, symmetry-breaking charge separation (SB-CS) was observed in dichloromethane. This process is fastest within the PBI cyclophane 2PBI(4-tBu)4 and slows down for larger cycles, suggesting that the charge separation takes place through space and not through bonds. The charges then recombine to the PBI triplet state via a radical pair intersystem crossing (RP-ISC) mechanism, which could be used to generate singlet oxygen in yields of ~20%.
By changing the solvent to toluene an intramolecular folding of the even-numbered larger cycles was observed that quenches the fluorescence and increases the 0-1 transition band in the absorption spectra. Force field calculations of 4PBI(4-tBu)4 suggested a folding into pairs of dimers, which explains the remarkable odd-even effect with respect to the number of connected PBI chromophores and the resulting alternation in the absorption and fluorescence properties. Thus, the even-numbered macrocycles can fold in a way that all chromophores are in a paired arrangement, while the odd-numbered cycles have open conformations (3PBI(4-tBu)4, 5PBI(4-tBu)4, 7PBI(4-tBu)4) or at least additional unpaired PBI unit (9PBI(4-tBu)4).
With these experiments we could for the first time give insights in the interactions between cyclic PBI hosts and aromatic guest molecules. Associated with the encapsulation of guest molecules a variety of possible applications can be envisioned, like fluorescence sensing, chiral recognition and photodynamic therapy by singlet oxygen generation. Particularly, these macrocycles provide photophysical relaxation pathways of PBIs, like charge separation and recombination and triplet state formation that are hardly feasible in monomeric PBI dyes. Furthermore, diverse compound specific features were found, like the odd-even effect in the folding process or the transition of superficial nanostructures of the tetrameric cycle influenced by the AFM tip. The comprehensive properties of these macrocycles provide the basis for further oncoming studies and can serve as an inspiration for the synthesis of new macrocyclic compounds.
The current dissertation addresses the analysis of technology-enhanced learning processes by using Process Mining techniques. For this purpose, students’ coded think-aloud data served as the measurement of the learning process, in order to assess the potential of this analysis method for evaluating the impact of instructional support.
The increasing use of digital media in higher education and further educational sectors enables new potentials. However, it also poses new challenges to students, especially regarding the self-regulation of their learning process. To help students with optimally making progress towards their learning goals, instructional support is provided during learning. Besides the use of questionnaires and tests for the assessment of learning, researchers make use increasingly of process data to evaluate the effects of provided support. The analysis of observed behavioral traces while learning (e.g., log files, eye movements, verbal reports) allows detailed insights into the student’s activities as well as the impact of interventions on the learning process. However, new analytical challenges emerge, especially when going beyond the analysis of pure frequencies of observed events. For example, the question how to deal with temporal dynamics and sequences of learning activities arises. Against this background, the current dissertation concentrates on the application of Process Mining techniques for the detailed analysis of learning processes. In particular, the focus is on the additional value of this approach in comparison to a frequency-based analysis, and therefore on the potential of Process Mining for the evaluation of instructional support.
An extensive laboratory study with 70 university students, which was conducted to investigate the impact of a support measure, served as the basis for pursuing the research agenda of this dissertation. Metacognitive prompts supported students in the experimental group (n = 35) during a 40-minute hypermedia learning session; whereas the control group (n = 35) received no support. Approximately three weeks later, all students participated in another learning session; however, this time all students learned without any help. The participants were instructed to verbalize their learning activities concurrently while learning. In the three analyses of this dissertation, the coded think aloud data were examined in detail by using frequency-based methods as well as Process Mining techniques.
The first analysis addressed the comparison of the learning activities between the experimental and control groups during the first learning session. This study concentrated on the research questions whether metacognitive prompting increases the number of metacognitive learning activities, whether a higher number of these learning activities corresponds with learning outcome (mediation), and which differences regarding the sequential structure of learning activities can be revealed. The second analysis investigated the impact of the individual prompts as well as the conditions of their effectiveness on the micro level. In addition to Process Mining, we used a data mining approach to compare the findings of both analysis methods. More specifically, we classified the prompts by their effectiveness, and we examined the learning activities preceding and following the presentation of instructional support. Finally, the third analysis considered the long-term effects of metacognitive prompting on the learning process during another learning session without support. It was the key objective of this study to examine which fostered learning activities and process patterns remained stable during the second learning session.
Overall, all three analyses indicated the additional value of Process Mining in comparison to a frequency-based analysis. Especially when conceptualizing the learning process as a dynamic sequence of multiple activities, Process Mining allows identifying regulatory loops and crucial routing points of the process. These findings might contribute to optimizing intervention strategies. However, before drawing conclusions for the design of instructional support based on the revealed process patterns, additional analyses need to investigate the generalizability of results. Moreover, the application of Process Mining remains challenging because guidelines for analytical decisions and parameter settings in technology-enhanced learning context are currently missing. Therefore, future studies need to examine further the potential of Process Mining as well as related analysis methods to provide researchers with concrete recommendations for use. Nevertheless, the application of Process Mining techniques can already contribute to advance the understanding of the impact of instructional support through the use of fine-grained process data.
Mechanisms of visual memory formation in bees: About immediate early genes and synaptic plasticity
(2017)
Animals form perceptual associations through processes of learning, and retain that information through mechanisms of memory. Honeybees and bumblebees are classic models for insect perception and learning, and despite their small brains with about one million neurons, they are organized in highly social colonies and possess an astonishing rich behavioral repertoire including navigation, communication and cognition. Honeybees are able to harvest hundreds of morphologically divergent flower types in a quick and efficient manner to gain nutrition and, back in the hive, communicate discovered food sources to nest mates. To accomplish such complex tasks, bees must be equipped with diverse sensory organs receptive to stimuli of different modalities and must be able to associatively learn and memorize the acquired information. Particularly color vision plays a prominent role, e.g. in navigation along landmarks and when bees identify inflorescences by their color signals. Once acquired, bees are known to retain visual information for days or even months. Numerous studies on visual perception and color vision have been conducted in the past decades and largely revealed the information processing pathways in the brain. In contrast, there are no data available on how the brain may change in the course of color learning experience and whether pathways differ for coarse and fine color learning. Although long-term memory (LTM) storage is assumed to generally include reorganization of the neuronal network, to date it is unclear where in the bee brain such changes occur in the course of color learning and whether visual memories are stored in one particular site or decentrally distributed over different brain domains. The present dissertation research aimed to dissect the visual memory trace in bees that is beyond mere stimulus processing and therefore two different approaches were elaborated: first, the application of immediate early genes (IEG) as genetic markers for neuronal activation to localize early processes underlying the formation of a stable LTM. Second, the analysis of late consequences of memory formation, including synaptic reorganization in central brain areas and dependencies of color discrimination complexity.
Immediate early genes (IEG) are a group of rapidly and transiently expressed genes that are induced by various types of cellular stimulation. A great number of different IEGs are routinely used as markers for the localization of neuronal activation in vertebrate brains. The present dissertation research was dedicated to establish this approach for application in bees, with focus on the candidate genes Amjra and Amegr, which are orthologous to the two common vertebrate IEGs c-jun and egr-1. First the general requirement of gene transcription for visual LTM formation was proved. Bumblebees were trained in associative proboscis extension response (PER) conditioning to monochromatic light and subsequently injected with an inhibitor of gene transcription. Memory retention tests at different intervals revealed that gene transcription is not required for the formation of a mid-term memory, but for stable LTM. Next, the appliance of the candidate genes was validated. Honeybees were exposed to stimulation with either alarm pheromone or a light pulse, followed by qPCR analysis of gene expression. Both genes differed in their expression response to sensory exposure: Amjra was upregulated in all analyzed brain parts (antennal lobes, optic lobes and mushroom bodies, MB), independent from stimulus modality, suggesting the gene as a genetic marker for unspecific general arousal. In contrast, Amegr was not significantly affected by mere sensory exposure. Therefore, the relevance of associative learning on Amegr expression was assessed. Honeybees were trained in visual PER conditioning followed by a qPCR-based analysis of the expression of all three Amegr isoforms at different intervals after conditioning. No learning-dependent alteration of gene expression was observed. However, the presence of AmEgr protein in virtually all cerebral cell nuclei was validated by immunofluorescence staining. The most prominent immune-reactivity was detected in MB calyx neurons.
Analysis of task-dependent neuronal correlates underlying visual long-term memory was conducted in free-flying honeybees confronted with either absolute conditioning to one of two perceptually similar colors or differential conditioning with both colors. Subsequent presentation of the two colors in non-rewarded discrimination tests revealed that only bees trained with differential conditioning preferred the previously learned color. In contrast, bees of the absolute conditioning group chose randomly among color stimuli. To investigate whether the observed difference in memory acquisition is also reflected at the level of synaptic microcircuits, so called microglomeruli (MG), within the visual domains of the MB calyces, MG distribution was quantified by whole-mount immunostaining three days following conditioning. Although learning-dependent differences in neuroarchitecture were absent, a significant correlation between learning performance and MG density was observed.
Taken together, this dissertation research provides fundamental work on the potential use of IEGs as markers for neuronal activation and promotes future research approaches combining behaviorally relevant color learning tests in bees with examination of the neuroarchitecture to pave the way for unraveling the visual memory trace.
Sponges (phylum Porifera) are evolutionary ancient, sessile filter-feeders that harbor a largely diverse microbial community within their internal mesohyl matrix. Throughout this thesis project, I aimed at exploring the adaptations of these symbionts to life within their sponge host by sequencing and analyzing the genomes of a variety of bacteria from the microbiome of the Mediterranean sponge Aplysina aerophoba. Employed methods were fluorescence-activated cell sorting with subsequent multiple displacement amplification and single-cell / ‘mini-metagenome’ sequencing, and metagenomic sequencing followed by differential coverage binning. These two main approaches both aimed at obtaining genome sequences of bacterial symbionts of A. aerophoba, that were then compared to each other and to references from other environments, to gain information on adaptations to the host sponge environment and on possible interactions with the host and within the microbial community.
Cyanobacteria are frequent members of the sponge microbial community. My ‘mini-metagenome’ sequencing project delivered three draft genomes of “Candidatus Synechococcus spongiarum,” the cyanobacterial symbiont of A. aerophoba and many more sponges inhabiting the photic zone. The most complete of these genomes was compared to other clades of this symbiont and to closely related free-living cyanobacterial references in a collaborative project published in Burgsdorf I*, Slaby BM* et al. (2015; *shared first authorship). Although the four clades of “Ca. Synechococcus spongiarum” from the four sponge species A. aerophoba, Ircinia variabilis, Theonella swinhoei, and Carteriospongia foliascens were approximately 99% identical on the level of 16S rRNA gene sequences, they greatly differed on the genomic level. Not only the genome sizes were different from clade to clade, but also the gene content and a number of features including proteins containing the eukaryotic-type domains leucine-rich repeats or tetratricopeptide repeats. On the other hand, the four clades shared a number of features such as ankyrin repeat domain-containing proteins that seemed to be conserved also among other microbial phyla in different sponge hosts and from different geographic locations. A possible novel mechanism for host phagocytosis evasion and phage resistance by means of an altered O antigen of the lipopolysaccharide was identified.
To test previous hypotheses on adaptations of sponge-associated bacteria on a broader spectrum of the microbiome of A. aerophoba while also taking a step forward in methodology, I developed a bioinformatic pipeline to combine metagenomic Illumina short-read sequencing data with PacBio long-read data. At the beginning of this project, no pipelines to combine short-read and long-read data for metagenomics were published, and at time of writing, there are still no projects published with a comparable aim of un-targeted assembly, binning and analysis of a metagenome. I tried a variety of assembly programs and settings on a simulated test dataset reflecting the properties of the real metagenomic data. The developed assembly pipeline improved not only the overall assembly statistics, but also the quality of the binned genomes, which was evaluated by comparison to the originally published genome assemblies.
The microbiome of A. aerophoba was studied from various angles in the recent years, but only genomes of the candidate phylum Poribacteria and the cyanobacterial sequences from my above-described project have been published to date. By applying my newly developed assembly pipeline to a metagenomic dataset of A. aerophoba consisting of a PacBio long-read dataset and six Illumina short-read datasets optimized for subsequent differential coverage binning, I aimed at sequencing a larger number and greater diversity of symbionts. The results of this project are currently in review by The ISME Journal. The complementation of Illumina short-read with PacBio long-read sequencing data for binning of this highly complex metagenome greatly improved the overall assembly statistics and improved the quality of the binned genomes. Thirty-seven genomes from 13 bacterial phyla and candidate phyla were binned representing the most prominent members of the microbiome of A. aerophoba. A statistical comparison revealed an enrichment of genes involved in restriction modification and toxin-antitoxin systems in most symbiont genomes over selected reference genomes. Both are defense features against incoming foreign DNA, which may be important for sponge symbionts due to the sponge’s filtration and phagocytosis activity that exposes the symbionts to high levels of free DNA. Also host colonization and matrix utilization features were significantly enriched. Due to the diversity of the binned symbiont genomes, a within-symbionts genome comparison was possible, that revealed three guilds of symbionts characterized by i) nutritional specialization on the metabolization of carnitine, ii) specialization on sulfated polysaccharides, and iii) apparent nutritional generalism. Both carnitine and sulfated polysaccharides are abundant in the sponge extracellular matrix and therefore available to the sponge symbionts as substrates. In summary, the genomes of the diverse community of symbionts in A. aerophoba were united in their defense features, but specialized regarding their nutritional preferences.
Exciton-polaritons in semiconductor microcavities form a highly nonlinear platform to study a variety of effects interfacing optical, condensed matter, quantum and statistical physics. We show that the complex polariton patterns generated by picosecond pulses in microcavity wire waveguides can be understood as the Cherenkov radiation emitted by bright polariton solitons, which is enabled by the unique microcavity polariton dispersion, which has momentum intervals with positive and negative group velocities. Unlike in optical fibres and semiconductor waveguides, we observe that the microcavity wire Cherenkov radiation is predominantly emitted with negative group velocity and therefore propagates backwards relative to the propagation direction of the emitting soliton. We have developed a theory of the microcavity wire polariton solitons and of their Cherenkov radiation and conducted a series of experiments, where we have measured polariton-soliton pulse compression, pulse breaking and emission of the backward Cherenkov radiation.
In the present work, the energetic structure and coherence properties of the silicon vacancy point defect in the technologically important material silicon carbide are extensively studied by the optically detected magnetic resonance (ODMR) technique in order to verify its high potential for various quantum applications. In the spin vacancy, unique attributes are arising from the C3v symmetry and the spin-3/2 state, which are not fully described by the standard Hamiltonian of the uniaxial model. Therefore, an advanced Hamiltonian, describing well the appearing phenomena is established and the relevant parameters are experimentally determined. Utilizing these new accomplishments, several quantum metrology techniques are proposed.
First, a vector magnetometry scheme, utilizing the appearance of four ODMR lines, allows for simultaneous detection of the magnetic field strength and the tilting angle of the magnetic field from the symmetry axis of the crystal.
The second magnetometry protocol utilizes the appearance of energetic level anticrossings (LAC) in the ground state (GS) energy levels. Relying only on the change in photoluminescence in the vicinity of this GSLACs, this all-optical method does not require any radio waves and hence provides a much easier operation with less error sources as for the common magnetometry schemes utilizing quantum points.
A similar all-optical method is applied for temperature sensing, utilizing the thermal shift of the zero field splitting and consequently the anticrossing in the excited state (ES). Since the GSLACs show no dependence on temperature, the all-optical magnetometry and thermometry (utilizing the ESLACs) can be conducted subsequently on the same defect.
In order to quantify the achievable sensitivity of quantum metrology, as well as to prove the potential of the Si-vacancy in SiC for quantum processing, the coherence properties are investigated by the pulsed ODMR technique. The spin-lattice relaxation time T1 and the spin-spin relaxation time T2 are thoroughly analyzed for their dependence on the external magnetic field and temperature.
For actual sensing implementations, it is crucial to obtain the best signal-to-noise ratio without loss in coherence time. Therefore, the irradiation process, by which the defects are created in the crystal, plays a decisive role in the device performance. In the present work, samples irradiated with electrons or neutrons with different fluences and energies, producing different defect densities, are analyzed in regard to their T1 and T2 times at room temperature.
Last but not least, a scheme to substantially prolong the T2 coherence time by locking the spin polarization with the dynamic decoupling Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence is applied.
Immature or semi-mature dendritic cells (DCs) represent tolerogenic maturation stages that can convert naive T cells into Foxp3\(^{+}\) induced regulatory T cells (iTreg). Here we found that murine bone marrow-derived DCs (BM-DCs) treated with cholera toxin (CT) matured by up-regulating MHC-II and costimulatory molecules using either high or low doses of CT (CT\(^{hi}\), CT\(^{lo}\)) or with cAMP, a known mediator CT signals. However, all three conditions also induced mRNA of both isoforms of the tolerogenic molecule cytotoxic T lymphocyte antigen 2 (CTLA-2α and CTLA-2β). Only DCs matured under CT\(^{hi}\) conditions secreted IL-1β, IL-6 and IL-23 leading to the instruction of Th17 cell polarization. In contrast, CT\(^{lo}\)- or cAMP-DCs resembled semi-mature DCs and enhanced TGF-β-dependent Foxp3\(^{+}\) iTreg conversion. iTreg conversion could be reduced using siRNA blocking of CTLA-2 and reversely, addition of recombinant CTLA-2α increased iTreg conversion in vitro. Injection of CT\(^{lo}\)- or cAMP-DCs exerted MOG peptide-specific protective effects in experimental autoimmune encephalomyelitis (EAE) by inducing Foxp3\(^{+}\) Tregs and reducing Th17 responses. Together, we identified CTLA-2 production by DCs as a novel tolerogenic mediator of TGF-β-mediated iTreg induction in vitro and in vivo. The CT-induced and cAMP-mediated up-regulation of CTLA-2 also may point to a novel immune evasion mechanism of Vibrio cholerae.
The purpose of this study was to develop and implement an in silico model of indigoid-based single-electron transistor (SET) nanodevices, which consist of indigoid molecules from natural dye weakly coupled to gold electrodes that function in a Coulomb blockade regime. The electronic properties of the indigoid molecules were investigated using the optimized density-functional theory (DFT) with a continuum model. Higher electron transport characteristics were determined for Tyrian purple, consistent with experimentally derived data. Overall, these results can be used to correctly predict and emphasize the electron transport functions of organic SETs, demonstrating their potential for sustainable nanoelectronics comprising the biodegradable and biocompatible materials.
Background: Although there is solid evidence for the efficacy of in vivo and virtual reality (VR) exposure therapy for a specific phobia, there is a significant debate over whether techniques promoting distraction or relaxation have impairing or enhancing effects on treatment outcome. In the present pilot study, we investigated the effect of diaphragmatic breathing (DB) as a relaxation technique during VR exposure treatment.
Method: Twenty-nine patients with aviophobia were randomly assigned to VR exposure treatment either with or without diaphragmatic breathing (six cycles per minute). Subjective fear ratings, heart rate and skin conductance were assessed as indicators of fear during both the exposure and the test session one week later.
Results: The group that experienced VR exposure combined with diaphragmatic breathing showed a higher tendency to effectively overcome the fear of flying. Psychophysiological measures of fear decreased and self-efficacy increased in both groups with no significant difference between the groups.
Conclusions: Our findings indicate that diaphragmatic breathing during VR exposure does not interfere with the treatment outcome and may even enhance treatment effects of VR exposure therapy for aviophobic patients.
Background: Cellular glucose uptake may involve either non-concentrative glucose carriers of the GLUT family or Na\(^+\)-coupled glucose-carrier SGLT1, which accumulates glucose against glucose gradients and may thus accomplish cellular glucose uptake even at dramatically decreased extracellular glucose oncentrations. SGLT1 is not only expressed in epithelia but as well in tumour cells and immune cells. Immune cell functions strongly depend on their metabolism, therefore we hypothesized that deficiency of SGLT1 modulates the defence against bacterial infection. To test this hypothesis, we infected wild type mice and gene targeted mice lacking functional SGLT1 with Listeria monocytogenes.
Methods: SGLT1 deficient mice and wild type littermates were infected with 1x10\(^4\) CFU Listeria monocytogenes intravenously. Bacterial titers were determined by colony forming assay, SGLT1, TNF-α, IL-6 and IL-12a transcript levels were determined by qRT-PCR, as well as SGLT1 protein abundance and localization by immunohistochemistry.
Results: Genetic knockout of SGLT1 (Slc5a1\(^{–/–}\) mice) significantly compromised bacterial clearance following Listeria monocytogenes infection with significantly enhanced bacterial load in liver, spleen, kidney and lung, and significantly augmented hepatic expression of TNF-α and IL-12a. While all wild type mice survived, all SGLT1 deficient mice died from the infection.
Conclusions: SGLT1 is required for bacterial clearance and host survival following murine Listeria infection.
RNA-binding proteins (RBPs) have been established as core components of several post-transcriptional gene regulation mechanisms. Experimental techniques such as cross-linking and co-immunoprecipitation have enabled the identification of RBPs, RNA-binding domains (RBDs) and their regulatory roles in the eukaryotic species such as human and yeast in large-scale. In contrast, our knowledge of the number and potential diversity of RBPs in bacteria is poorer due to the technical challenges associated with the existing global screening approaches. We introduce APRICOT, a computational pipeline for the sequence-based identification and characterization of proteins using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences using position-specific scoring matrices and Hidden Markov Models of the functional domains and statistically scores them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them by several biological properties. Here we demonstrate the application and adaptability of the pipeline on large-scale protein sets, including the bacterial proteome of Escherichia coli. APRICOT showed better performance on various datasets compared to other existing tools for the sequence-based prediction of RBPs by achieving an average sensitivity and specificity of 0.90 and 0.91 respectively. The command-line tool and its documentation are available at https://pypi.python.org/pypi/bio-apricot.
RNA-binding proteins (RBPs) have been extensively studied in eukaryotes, where they post-transcriptionally regulate many cellular events including RNA transport, translation, and stability. Experimental techniques, such as cross-linking and co-purification followed by either mass spectrometry or RNA sequencing has enabled the identification and characterization of RBPs, their conserved RNA-binding domains (RBDs), and the regulatory roles of these proteins on a genome-wide scale. These developments in quantitative, high-resolution, and high-throughput screening techniques have greatly expanded our understanding of RBPs in human and yeast cells. In contrast, our knowledge of number and potential diversity of RBPs in bacteria is comparatively poor, in part due to the technical challenges associated with existing global screening approaches developed in eukaryotes.
Genome- and proteome-wide screening approaches performed in silico may circumvent these technical issues to obtain a broad picture of the RNA interactome of bacteria and identify strong RBP candidates for more detailed experimental study. Here, I report APRICOT (“Analyzing Protein RNA Interaction by Combined Output Technique”), a computational pipeline for the sequence-based identification and characterization of candidate RNA-binding proteins encoded in the genomes of all domains of life using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences of an input proteome using position-specific scoring matrices and hidden Markov models of all conserved domains available in the databases and then statistically score them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them according to functionally relevant structural properties. APRICOT performed better than other existing tools for the sequence-based prediction on the known RBP data sets. The applications and adaptability of the software was demonstrated on several large bacterial RBP data sets including the complete proteome of Salmonella Typhimurium strain SL1344. APRICOT reported 1068 Salmonella proteins as RBP candidates, which were subsequently categorized using the RBDs that have been reported in both eukaryotic and bacterial proteins. A set of 131 strong RBP candidates was selected for experimental confirmation and characterization of RNA-binding activity using RNA co-immunoprecipitation followed by high-throughput sequencing (RIP-Seq) experiments. Based on the relative abundance of transcripts across the RIP-Seq libraries, a catalogue of enriched genes was established for each candidate, which shows the RNA-binding potential of 90% of these proteins. Furthermore, the direct targets of few of these putative RBPs were validated by means of cross-linking and co-immunoprecipitation (CLIP) experiments.
This thesis presents the computational pipeline APRICOT for the global screening of protein primary sequences for potential RBPs in bacteria using RBD information from all kingdoms of life. Furthermore, it provides the first bio-computational resource of putative RBPs in Salmonella, which could now be further studied for their biological and regulatory roles. The command line tool and its documentation are available at https://malvikasharan.github.io/APRICOT/.
This thesis investigates the impact of the country-of-origin effect on Chinese luxury brands which intend to enter the German luxury goods market. By means of a questionnaire and a quantitative analysis, possible threats to Chinese newcomers that derive from an unfavorable country image are illustrated. In fact, the Chinese origin of luxury goods has an impact on German consumers' perception.