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Sonstige beteiligte Institutionen
Estimating flood risks and managing disasters combines knowledge in climatology, meteorology, hydrology, hydraulic engineering, statistics, planning and geography - thus a complex multi-faceted problem. This study focuses on the capabilities of multi-source remote sensing data to support decision-making before, during and after a flood event. With our focus on urbanized areas, sample methods and applications show multi-scale products from the hazard and vulnerability perspective of the risk framework. From the hazard side, we present capabilities with which to assess flood-prone areas before an expected disaster. Then we map the spatial impact during or after a flood and finally, we analyze damage grades after a flood disaster. From the vulnerability side, we monitor urbanization over time on an urban footprint level, classify urban structures on an individual building level, assess building stability and quantify probably affected people. The results show a large database for sustainable development and for developing mitigation strategies, ad-hoc coordination of relief measures and organizing rehabilitation.
Visceral pentastomiasis caused by Armillifer armillatus larvae was diagnosed in 2 dogs in The Gambia. Parasites were subjected to PCR; phylogenetic analysis confirmed relatedness with branchiurans/crustaceans. Our investigation highlights transmission of infective A. armillatus ova to dogs and, by serologic evidence, also to 1 human, demonstrating a public health concern.
We consider the prospects for a neutrino factory measuring mixing angles, the CP violating phase and mass-squared differences by detecting wrong-charge muons arising from the chain $\mu^+\to\nu_e\to\nu_\mu\to\mu^-$ and the right-charge muons coming from the chain $\mu^+\to\bar{\nu}_\mu\to\bar{\nu}_\mu\to\mu^+$ (similar to $\mu^-$ chains), where $\nu_e\to\nu_\mu$ and $\bar{\nu}_\mu\to\bar{\nu}_\mu$ are neutrino oscillation channels through a long baseline. First, we study physics with near detectors and consider the treatment of systematic errors including cross section errors, flux errors, and background uncertainties. We illustrate for which measurements near detectors are required, discuss how many are needed, and what the role of the flux monitoring is. We demonstrate that near detectors are mandatory for the leading atmospheric parameter measurements if the neutrino factory has only one baseline, whereas systematic errors partially cancel if the neutrino factory complex includes the magic baseline. Second, we perform the baseline and energy optimization of the neutrino factory including the latest simulation results from the magnetized iron neutrino detector (MIND). We also consider the impact of $\tau$ decays, generated by appearance channels $\nu_\mu \rightarrow \nu_\tau$ and $\nu_e \rightarrow \nu_\tau$, on the discovery reaches of the mass orderings, the leptonic CP violation, and the non-zero $\theta_{13}$, which we find to be negligible for the considered detector. Third, we make a comparison of a high energy neutrino factory to a low energy neutrino factory and find that they are just two versions of the same experiment optimized for different regions of the parameter space. In addition, we briefly comment on whether it is useful to build the bi-magic baseline at the low energy neutrino factory. Finally, the effects of one additional massive sterile neutrino are discussed in the context of a combined short and long baseline setup. It is found that near detectors can provide the required sensitivity at the LSND-motivated $\Delta m_{41}^2$-range, while some sensitivity can also be obtained in the region of the atmospheric mass splitting introduced by the sterile neutrino from the long baselines.
Marine sponges and their associated bacteria have been proven to be a rich source of novel secondary metabolites with therapeutic usefulness in infection and autoimmunity. This Ph.D. project aimed to isolate bioactive secondary metabolites from the marine sponges Amphimedon compressa, Aiolochroia crassa and Theonella swinhoei as well as from bacteria associated with different Caribbean sponges, specifically actinomycetes and sphingomonads. In this study, amphitoxin was isolated from the crude methanol extract of the sponge A. compressa and it was found to have antibacterial and anti-parasitic activities. Amphitoxin showed protease inhibitory activity when tested against the mammalian protease cathepsin B and the parasitic proteases rhodesain and falcipain-2. Furthermore, miraziridine A was identified in the dichloromethane extract of the sponge T. swinhoei collected offshore Israel in the Red Sea. Miraziridine A, a natural peptide isolated previously from the marine sponge Theonella aff. mirabilis, is a potent cathepsin B inhibitor with an IC50 value of 1.4 g/mL (2.1 M). Secondary metabolites from sponge-derived bacteria were also isolated and identified. A total of 79 strains belonging to 20 genera of the order Actinomycetales and seven strains belonging to two genera of the order Sphingomonadales were cultivated from 18 different Caribbean sponges and identified by 16S rRNA gene sequencing. Seven of these strains are likely to represent novel species. Crude extracts from selected strains were found to exhibit protease inhibition against cathepsins B and L, rhodesain, and falcipain-2 as well as immunomodulatory activities such as induction of cytokine release by human peripheral blood mononuclear cells. The isolates Sphingobium sp. CO105 and Lapillicoccus sp. BA53 were selected for cultivation, extraction and purification of bioactive metabolites based on initial bioactive screening results. The isoalloxazine isolumichrome was isolated from the strain Sphingobium sp. CO105 which inhibited the protease rhodesain with an IC50 of 0.2 M. The strain Lapillicoccus sp. BA53 was found to produce p-aminosalicylic acid methyl ester, which showed activity against the proteases cathepsins B and L, falcipain-2 and rhodesain. These results highlight the significance of marine sponge-associated bacteria to produce bioactive secondary metabolites with therapeutic potential in the treatment of infectious diseases and disorders of the immune system.
Magnetic Resonance Imaging of Tumors Colonized with Bacterial Ferritin-Expressing Escherichia coli
(2011)
Background: Recent studies have shown that human ferritin can be used as a reporter of gene expression for magnetic resonance imaging (MRI). Bacteria also encode three classes of ferritin-type molecules with iron accumulation properties. Methods and Findings: Here, we investigated whether these bacterial ferritins can also be used as MRI reporter genes and which of the bacterial ferritins is the most suitable reporter. Bacterial ferritins were overexpressed in probiotic E. coli Nissle 1917. Cultures of these bacteria were analyzed and those generating highest MRI contrast were further investigated in tumor bearing mice. Among members of three classes of bacterial ferritin tested, bacterioferritin showed the most promise as a reporter gene. Although all three proteins accumulated similar amounts of iron when overexpressed individually, bacterioferritin showed the highest contrast change. By site-directed mutagenesis we also show that the heme iron, a unique part of the bacterioferritin molecule, is not critical for MRI contrast change. Tumor-specific induction of bacterioferritin-expression in colonized tumors resulted in contrast changes within the bacteria-colonized tumors. Conclusions: Our data suggest that colonization and gene expression by live vectors expressing bacterioferritin can be monitored by MRI due to contrast changes
Spontaneous neural activity has been shown to regulate crucial events in neurite growth including axonal branching and path finding. In animal models of spinal muscular atrophy (SMA) cultured embryonic mouse motoneurons show distinct defect in axon elongation and neural activity. This defect is governed by abnormal clustering of Ca2+ channels in the axonal regions and the protruding growth cone area. The mechanisms that regulate the opening of calcium channels in developing motoneurons are not yet clear. The question was addressed by blocking neural activity in embryonic cultured motoneurons by pharmacological inhibition of voltage-gated sodium channels (VGSC) by saxitoxin (STX) and tetrodotoxin (TTX). Low dosages of STX resulted in significant reduction of axon growth and neural activity in cultured motoneurons. This pharmacological treatment did not affect survival of motoneurons in comparison to control motoneurons that was grown in the presence of survival neurotrophic factors BDNF and CNTF. It was also found that STX was 10 times more potent than TTX a common inhibitor of VGSC with a reduced activity on the TTX-insensitive sodium channels NaV1.5, NaV1.8 and NaV1.9. Reverse Transcriptase-PCR experiments revealed the presence of NaV1.9 as the likely candidate that begins to express from embryonic stage sixteen in the mouse spinal cord. Immunolabelling experiments showed that the channel is expressed in the axonal compartments and axonal growth cones in cultured motoneurons. Suppression of NaV1.9 in cultured motoneurons by lentivirus mediated short hairpin-RNA (shRNA) resulted in shorter axon length in comparison with uninfected and scrambled constructs. Further, embryonic motoneurons cultured from NaV1.9 knockout mice also showed a significant reduction in neural activity and axon growth. The findings of this work highlight the role of NaV1.9 as an important contender in regulating activity dependent axon growth in embryonic cultured motoneurons. NaV1.9 could therefore be considered as a prospective molecule that could play an important role in regulating axon growth in motoneuron disease models like spinal muscular atrophy (SMA).
Switches in trypanosome differentiation: ALBA proteins acting on post-transcriptional mRNA control
(2011)
Trypanosoma brucei is a digenetic eukaryotic parasite that develops in different tissues of a mammalian host and a tsetse fly. It is responsible for sleeping sickness in sub-saharan Africa. The parasite cycle involves more than nine developmental stages that can be clearly distinguished by their general morphology, their metabolism and the relative positioning of their DNA-containing organelles. During their development, trypanosomes remain exclusively extracellular and encounter changing environments with different physico-chemical properties (nutritional availability, viscosity, temperature, etc.). It has been proposed that trypanosomes use their flagellum as a sensing organelle, in agreement with the established role of structurally-related cilia in metazoa and ciliates. Recognition of environmental triggers is presumed to be at the initiation of differentiation events, leading to the parasite stage that is the best suited to the new environment. These changes are achieved by the modification of gene expression programmes, mostly underlying post-transcriptional control of mRNA transcripts. We first demonstrate that the RNA-binding proteins ALBA3/4 are involved in specific differentiation processes during the parasite development in the fly. They are cytosolic and expressed throughout the parasite cycle with the exception of the stages found in the tsetse fly proventriculus, as shown by both immunofluorescence and live cell analysis upon endogenous tagging with YFP. Knock-down of both proteins in the developmental stage preceding these forms leads to striking modifications: cell elongation, cell cycle arrest and relocalization of the nucleus in a posterior position, all typical of processes acting in parasites found in the proventriculus region. When ALBA3 is over-expressed from an exogenous copy during infection, it interferes with the relocalization of the nucleus in proventricular parasites. This is not observed for ALBA4 over-expression that does not visibly impede differentiation. Both ALBA3/4 proteins react to starvation conditions by accumulating in cytoplasmic stress granules together with DHH1, a recognized RNA-binding protein. ALBA3/4 proteins also partially colocalize with granules formed by polyA+ RNA in these conditions. We propose that ALBA are involved in trypanosome differentiation processes where they control a subset of developmentally regulated transcripts. These processes involving ALBA3/4 are likely to result from the specific activation of sensing pathways. In the second part of the thesis, we identify novel flagellar proteins that could act in sensing mechanisms. Several protein candidates were selected from a proteomic analysis of intact flagella performed in the host laboratory. This work validates their flagellar localization with high success (85% of the proteins examined) and defines multiple different patterns of protein distribution in the flagellum. Two proteins are analyzed during development, one of them showing down-regulation in proventricular stages. The functional analysis of one novel flagellar membrane protein reveals its rapid dynamics within the flagellum but does not yield a visible phenotype in culture. This is coherent with sensory function that might not be needed in stable culture conditions, but could be required in natural conditions during development. In conclusion, this work adds new pieces to the puzzle of identifying molecular switches involved in developmental mRNA control and environmental sensing in trypanosome stages in the tsetse fly.
Background: Data on complications in children with seasonal influenza virus infection are limited. We initiated a nation-wide three-year surveillance of children who were admitted to a paediatric intensive care unit (PICU) with severe seasonal influenza. Methods: From October 2005 to July 2008, active surveillance was performed using an established reporting system for rare diseases (ESPED) including all paediatric hospitals in Germany. Cases to be reported were hospitalized children < 17 years of age with laboratory-confirmed influenza treated in a PICU or dying in hospital. Results: Twenty severe influenza-associated cases were reported from 14 PICUs during three pre-pandemic influenza seasons (2005-2008). The median age of the patients (12 males/8 females) was 7.5 years (range 0.1-15 years). None had received vaccination against influenza. In 14 (70%) patients, the infection had been caused by influenza A and in five (25%) by influenza B; in one child (5%) the influenza type was not reported. Patients spent a median of 19 (IQR 12-38) days in the hospital and a median of 11 days (IQR 6-18 days) in the PICU; 10 (50%) needed mechanical ventilation. Most frequent diagnoses were influenza-associated pneumonia (60%), bronchitis / bronchiolitis (30%), encephalitis / encephalopathy (25%), secondary bacterial pneumonia (25%), and ARDS (25%). Eleven (55%) children had chronic underlying medical conditions, including 8 (40%) with chronic pulmonary diseases. Two influenza A- associated deaths were reported: i) an 8-year old boy with pneumococcal encephalopathy following influenza infection died from cerebral edema, ii) a 14-year-old boy with asthma bronchiale, cardiac malformation and Addison’s disease died from cardiac and respiratory failure. For nine (45%) patients, possibly permanent sequelae were reported (3 neurological, 3 pulmonary, 3 other sequelae). Conclusions: Influenza-associated pneumonia and secondary bacterial infections are relevant complications of seasonal influenza in Germany. The incidence of severe influenza cases in PICUs was relatively low. This may be either due to the weak to moderate seasonal influenza activity during the years 2005 to 2008 or due to underdiagnosis of influenza by physicians. Fifty % of the observed severe cases might have been prevented by following the recommendations for vaccination of risk groups in Germany.
Polarity and migration are essential for T cell activation, homeostasis, recirculation and effector function. To address how T cells coordinate polarization and migration when interacting with dendritic cells (DC) during homeostatic and activating conditions, a low density collagen model was used for confocal live-cell imaging and high-resolution 3D reconstruction of fixed samples. During short-lived (5 to 15 min) and migratory homeostatic interactions, recently activated T cells simultaneously maintained their amoeboid polarization and polarized towards the DC. The resulting fully dynamic and asymmetrical interaction plane comprised all compartments of the migrating T cell: the actin-rich leading edge drove migration but displayed only moderate signaling activity; the mid-zone mediated TCR/MHC induced signals associated with homeostatic proliferation; and the rear uropod mediated predominantly MHC independent signals possibly connected to contact-dependent T cell survival. This “dynamic immunological synapse” with distinct signaling sectors enables moving T cells to serially sample antigen-presenting cells and resident tissue cells and thus to collect information along the way. In contrast to homeostatic contacts, recognition of the cognate antigen led to long-lasting T cell/DC interaction with T cell rounding, disintegration of the uropod, T cell polarization towards the DC, and the formation of a symmetrical contact plane. However, the polarity of the continuously migrating DC remained intact and T cells aggregated within the DC uropod, an interesting cellular compartment potentially involved in T cell activation and regulation of the immune response. Taken together, 3D collagen facilitates high resolution morphological studies of T cell function under realistic, in vivo-like conditions.
The nicotinic acetylcholine receptor of skeletal muscle is one of the best-investigated synaptic proteins and often serves as model for the entire family of pentameric ligand gated ion channels (pLGICs). Receptors of this superfamily share a common architecture. After binding the agonist the characteristic C-loop structure closes around the ligand-binding site and triggers a wave of conformational changes that spread through the protein and finally result in the opening of the channel gate. As shown before, high-resolution single channel data can hardly be described by simple kinetic mechanisms (Parzefall et al., 1998, Hallermann et al., 2005). Recent advances in the field of kinetic modelling on receptor currents demonstrate that the introduction of additional short lived shut states in kinetic schemes enhances the quality of estimates of reaction rates. The additional shut states that immediately follow ligand bound states in the mechanism are suggested to resemble the closing movement of the C-loop (Lape et al., 2008; Mukhtasimova et al., 2009). It has not been described yet whether and how the structural differences of the 2 binding sites of the receptor influence the opening behaviour. To address this question, high-resolution single channel recordings, in combination with agonists that are known to exhibit different binding site selectivity, were performed. Thereby, a detailed description of the binding site dependent generation of channel currents is possible. At the embryonic mouse-muscle receptor used in this study the ligand binding sites are located at the α-γ and α-δ subunit interfaces. By allocation of opening characteristics to the α-δ and α-γ sites it is possible to show the binding site dependent activation of distinct kinetic states. Furthermore, it will be shown that the recently introduced short-lived shut states are sufficient to describe high-resolution single channel data. Finally an enhanced kinetic mechanism based on the ‘primed states’ model, published in 2009 by Mukhtasimova et al., will be presented. In this model the structurally diverse α-δ and α-γ binding sites elicit different kinetic channel characteristics. Thus the complex high-resolution kinetic characteristics of the embryonic receptor can be described coherently.
Desert ants of the genus Cataglyphis possess remarkable visual navigation capabilities. Although Cataglyphis species lack a trail pheromone system, Cataglyphis fortis employs olfactory cues for detecting nest and food sites. To investigate potential adaptations in primary olfactory centers of the brain of C. fortis, we analyzed olfactory glomeruli (odor processing units) in their antennal lobes and compared them to glomeruli in different Cataglyphis species. Using confocal imaging and 3D reconstruction, we analyzed the number, size and spatial arrangement of olfactory glomeruli in C. fortis, C.albicans, C.bicolor, C.rubra, and C.noda. Workers of all Cataglyphis species have smaller numbers of glomeruli (198–249) compared to those previously found in olfactory-guided ants. Analyses in 2 species of Formica – a genus closely related to Cataglyphis – revealed substantially higher numbers of olfactory glomeruli (c. 370), which is likely to reflect the importance of olfaction in these wood ant species. Comparisons between Cataglyphis species revealed 2 special features in C. fortis. First, with c. 198 C. fortis has the lowest number of glomeruli compared to all other species. Second, a conspicuously enlarged glomerulus is located close to the antennal nerve entrance. Males of C. fortis possess a significantly smaller number of glomeruli (c. 150) compared to female workers and queens. A prominent male-specific macroglomerulus likely to be involved in sex pheromone communication occupies a position different from that of the enlarged glomerulus in females. The behavioral significance of the enlarged glomerulus in female workers remains elusive. The fact that C. fortis inhabits microhabitats (salt pans) that are avoided by all other Cataglyphis species suggests that extreme ecological conditions may not only have resulted in adaptations of visual capabilities, but also in specializations of the olfactory system.
Desert ants of the genus Cataglyphis have become model systems for the study of insect navigation. An age-related polyethism subdivides their colonies into interior workers and short-lived light-exposed foragers. While foraging in featureless and cluttered terrain over distances up to several hundred meters, the ants are able to precisely return back to their often inconspicuous nest entrance. They accomplish this enormous navigational performance by using a path integration system - including a polarization compass and an odometer - as their main navigational means in addition to landmark-dependent orientation and olfactory cues. C. fortis, being the focus of the present thesis, is endemic to the salt flats of western North Africa, which are completely avoided by other Cataglyphis species. The fact that Cataglyphis ants undergo a behavioral transition associated with drastically changing sensory demands makes these ants particularly interesting for studying synaptic plasticity in visual and olfactory brain centers. This thesis focuses on plastic changes in the mushroom bodies (MBs) - sensory integration centers supposed to be involved in learning and memory presumably including landmark learning - and in synaptic complexes belonging to the lateral accessory lobe (LAL) known to be a relay station in the polarization processing pathway. To investigate structural synaptic plasticity in the MBs of C. fortis, synaptic complexes (microglomeruli, MG) in the visual (collar) and olfactory (lip) input regions of the MB calyx were immunolabeled and their pre- and postsynaptic profiles were quantified. The results show that a volume increase of the MB calyx during behavioral transition is associated with a decrease of MG number - an effect called pruning - in the collar and, less pronounced, in the lip that goes along with dendritic expansion in MB intrinsic Kenyon cells. Light-exposure of dark-reared ants of different age classes revealed similar effects and dark-reared ants age-matched to foragers had MG numbers comparable to those of interior workers. The results indicate that the enormous structural synaptic plasticity of the MB calyx collar is primarily driven by visual experience rather than by an internal program. Ants aged artificially for up to one year expressed a similar plasticity indicating that the system remains flexible over the entire life-span. To investigate whether light-induced synaptic reorganization is reversible, experienced foragers were transferred back to darkness with the result that their MBs exhibit only some reverse-type characteristics, in particular differences in presynaptic synapsin expression. To investigate the structure of large synaptic complexes in the LAL of C. fortis and to detect potential structural changes, pre- and postsynaptic profiles in interior workers and foragers were immunolabeled and quantified by using confocal imaging and 3D-reconstruction. The results show that these complexes consist of postsynaptic processes located in a central region that is surrounded by a cup-like presynaptic profile. Tracer injections identified input and output tracts of the LAL: projection neurons from the anterior optic tubercle build connections with neurons projecting to the central complex. The behavioral transition is associated with an increase by ~13% of synaptic complexes suggesting that the polarization pathway may undergo some sort of calibration process. The structural features of these synaptic contacts indicate that they may serve a fast and reliable signal transmission in the polarization vision pathway. Behavioral analyses of C. fortis in the field revealed that the ants perform exploration runs including pirouette-like turns very close to the nest entrance for a period of up to two days, before they actually start their foraging activity. During these orientation runs the ants gather visual experience and might associate the nest entrance with specific landmarks or get entrained to other visual information like the polarization pattern, and, concomitantly adapt their neuronal circuitries to the upcoming challenges. Moreover, the pirouettes may serve to stimulate and calibrate the neuronal networks involved in the polarization compass pathway. Video recordings and analyses demonstrate that light experience enhanced the ants’ locomotor activity after three days of exposure. The fact that both the light-induced behavioral and neuronal changes in visual brain centers occur in the same time frame suggests that there may be a link between structural synaptic plasticity and the behavioral transition from interior tasks to outdoor foraging. Desert ants of the genus Cataglyphis possess remarkable visual navigation capabilities, but also employ olfactory cues for detecting nest and food sites. Using confocal imaging and 3D-reconstruction, potential adaptations in primary olfactory brain centers were analyzed by comparing the number, size and spatial arrangement of olfactory glomeruli in the antennal lobe of C. fortis, C. albicans, C. bicolor, C. rubra, and C. noda. Workers of all Cataglyphis species have smaller numbers of glomeruli compared to those of more olfactory-guided Formica species - a genus closely related to Cataglyphis - and to those previously found in other olfactory-guided ant species. C. fortis has the lowest number of glomeruli compared to all other species, but possesses a conspicuously enlarged glomerulus that is located close to the antennal nerve entrance. Males of C. fortis have a significantly smaller number of glomeruli compared to female workers and queens and a prominent male-specific macroglomerulus likely to be involved in sex pheromone communication. The behavioral significance of the enlarged glomerulus in female workers remains elusive. The fact that C. fortis inhabits microhabitats that are avoided by all other Cataglyphis species suggests that extreme ecological conditions may not only have resulted in adaptations of visual capabilities, but also in specializations of the olfactory system. The present thesis demonstrates that Cataglyphis is an excellent candidate for studying the neuronal mechanisms underlying navigational features and for studying neuronal plasticity associated with the ant’s lifelong flexibility of individual behavioral repertoires.
Background:
The vital importance of imaging techniques in radiation oncology now extends beyond diagnostic evaluation and treatment planning. Recent technical advances have enabled the integration of various imaging modalities into the everyday practice of radiotherapy directly at the linear accelerator, improving the management of inter-and intrafractional variations.
Methods:
We present the topic of image-guided radiotherapy (IGRT) on the basis of a selective review of the literature.
Results:
IGRT can be performed with the aid of ultrasound, 2D X-ray devices, and computed tomography. It enables instant correction for positioning deviations and thereby improves the precision of daily radiotherapy fractions. It also enables immediate adjustment for changes in the position and filling status of the internal organs. Anatomical changes that take place over the course of radiotherapy, such as weight loss, tumor shrinkage, and the opening of atelectases, can be detected as they occur and accounted for in dosimetric calculations. There have not yet been any randomized controlled trials showing that IGRT causes fewer adverse effects or improves tumor control compared to conventional radiotherapy.
Conclusion:
IGRT is more precise and thus potentially safer than conventional radiotherapy. It also enables the application of special radiotherapeutic techniques with narrow safety margins in the vicinity of radiosensitive organs. Proper patient selection for IGRT must take account of the goals of treatment and the planning characteristics, as well as the available technical and human resources. IGRT should be used for steep dose gradients near organs at risk, for highly conformal dose distributions in the gastrointestinal tract where adjustment for filling variations is needed, for high-precision dose escalation to avoid geographic miss, and for patients who cannot lie perfectly still because of pain or claustrophobia.
Just do it! Guilt as a moral intuition to cooperate - A parallel constraint satisfaction approach
(2011)
After a long dominance of rational models of judgment and decision-making in moral psychology (e.g. Kohlberg, 1969) there is now a strong interest in how intuitions and emotions influence moral judgments and decisions (e.g. Greene, 2007; Haidt, 2001; Monin, Pizarro, & Beer, 2007). In the literature, the influence of emotions on moral decisions is explained by heuristic or non-compensatory information processing (e.g. Sinnott-Armstrong, Young, & Cushman, 2010; Sunstein, 2005; Tobler, Kalis, & Kalenscher, 2008). However, the process of emotion elicitation is ignored. Appraisal theories postulate that emotion elicitation is due to the incoherence (or discrepancy) of behavioral representations like goals and actions (Moors, 2009). Emotion elicitation and intuitive decision-making can be combined if both processes apply a connectionist information processing structure (e.g. Barnes & Thagard, 1996). The current work contrasts both perspectives of intuitive-emotional decision-making with respect to guilt and cooperation.
Introduction
Cochlear implants known to provide support in individuals with bilateral hearing loss may also be of great benefit for individuals with unilateral hearing loss. This case report demonstrates the positive effects of cochlear implantation on speech understanding in noise conditions in patients with unilateral hearing loss and normal hearing on the contralateral side. To the best of our knowledge, the data presented here are from the first few cases to receive a cochlear implant for unilateral hearing loss.
Case presentation
Four Caucasian German men, two aged 48 and the others aged 51 and 57 years old, with post-lingual unilateral hearing loss and normal hearing on the contralateral side were implanted with a cochlear implant. All our patients were members of the German army. Before and after implantation, they were given a battery of speech tests in different hearing conditions to assess the effect of unilateral cochlear implantation on speech understanding in noise conditions. Test results showed that all patients benefited from unilateral cochlear implantation, particularly in terms of speech understanding in noise conditions.
Conclusions
Unilateral cochlear implantation might be a successful treatment method for patients with unilateral hearing loss not benefiting from alternative treatment options. The results of this case report open up the field of cochlear implantation for expanded criteria and new areas of research.
In the future Internet, the people-centric communication paradigm will be complemented by a ubiquitous communication among people and devices, or even a communication between devices. This comes along with the need for a more flexible, cheap, widely available Internet access. Two types of wireless networks are considered most appropriate for attaining those goals. While wireless sensor networks (WSNs) enhance the Internet’s reach by providing data about the properties of the environment, wireless mesh networks (WMNs) extend the Internet access possibilities beyond the wired backbone. This monograph contains four chapters which present modeling and optimization methods for WSNs and WMNs. Minimizing energy consumptions is the most important goal of WSN optimization and the literature consequently provides countless energy consumption models. The first part of the monograph studies to what extent the used energy consumption model influences the outcome of analytical WSN optimizations. These considerations enable the second contribution, namely overcoming the problems on the way to a standardized energy-efficient WSN communication stack based on IEEE 802.15.4 and ZigBee. For WMNs both problems are of minor interest whereas the network performance has a higher weight. The third part of the work, therefore, presents algorithms for calculating the max-min fair network throughput in WMNs with multiple link rates and Internet gateway. The last contribution of the monograph investigates the impact of the LRA concept which proposes to systematically assign more robust link rates than actually necessary, thereby allowing to exploit the trade-off between spatial reuse and per-link throughput. A systematical study shows that a network-wide slightly more conservative LRA than necessary increases the throughput of a WMN where max-min fairness is guaranteed. It moreover turns out that LRA is suitable for increasing the performance of a contention-based WMN and is a valuable optimization tool.
The transcription factor Lmx1b is essential for the differentiation and survival of central serotonergic (5-HTergic) neurons during embryonic development. However, the role of Lmx1b in adult 5-HTergic neurons is unknown. We used an inducible Cre-LoxP system to selectively inactivate Lmx1b expression in the raphe nuclei of adult mice. Pet1-CreER(T2) mice were generated and crossed with Lmx1b(flox/flox) mice to obtain Pet1-CreER(T2); Lmx1b(flox/flox) mice (which termed as Lmx1b iCKO). After administration of tamoxifen, the level of 5-HT in the brain of Lmx1b iCKO mice was reduced to 60% of that in control mice, and the expression of tryptophan hydroxylase 2 (Tph2), serotonin transporter (Sert) and vesicular monoamine transporter 2 (Vmat2) was greatly down-regulated. On the other hand, the expression of dopamine and norepinephrine as well as aromatic L-amino acid decarboxylase (Aadc) and Pet1 was unchanged. Our results reveal that Lmx1b is required for the biosynthesis of 5-HT in adult mouse brain, and it may be involved in maintaining normal functions of central 5-HTergic neurons by regulating the expression of Tph2, Sert and Vmat2.
Background: Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain. Methods: We translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles. Results: Using a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct. Conclusions: The NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain.
The reliability of implantable blood sensors is often hampered by unspecific adsorption of plasma proteins and blood cells. This not only leads to a loss of sensor signal over time, but can also result in undesired host vs. graft reactions. Within this study we evaluated the hemocompatibility of isocyanate conjugated star shaped polytheylene oxide-polypropylene oxide co-polymers NCO-sP(EO-stat-PO) when applied to gold surfaces as an auspicious coating material for gold sputtered blood contacting sensors. Quartz crystal microbalance (QCM) sensors were coated with ultrathin NCO-sP(EO-stat-PO) films and compared with uncoated gold sensors. Protein resistance was assessed by QCM measurements with fibrinogen solution and platelet poor plasma (PPP), followed by quantification of fibrinogen adsorption. Hemocompatibility was tested by incubation with human platelet rich plasma (PRP). Thrombin antithrombin-III complex (TAT), beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) were used as coagulation activation markers. Furthermore, scanning electron microscopy (SEM) was used to visualize platelet adhesion to the sensor surfaces. Compared to uncoated gold sensors, NCO-sP(EO-stat-PO) coated sensors revealed significant better resistance against protein adsorption, lower TAT generation and a lower amount of adherent platelets. Moreover, coating with ultrathin NCO-sP(EO-stat-PO) films creates a cell resistant hemocompatible surface on gold that increases the chance of prolonged sensor functionality and can easily be modified with specific receptor molecules.
At the present day the idea of cosmological inflation constitutes an important extension of Big Bang theory. Since its appearance in the early 1980’s many physical mechanisms have been worked out that put the inflationary expansion of space that proceeds the Hot Big Bang on a sound theoretical basis. Among the achievements of the theory of inflation are the explanaition of the almost Euclidean geometry of ‘visible’space, the homogeneity of the cosmic background radiation but, in particular, also the tiny inhomogeneity of a relative amplitude of 10−5. In many models of inflation the inflationary phase ends only locally. Hence, there exists the possibility that the inflationary process still goes on in regions beyond our visual horizon. This property is commonly termed ‘eternal inflation’. In the framework of a cosmological scalar fields, eternal inflation can manifest itself in a variety of ways. On the one hand fluctuations of the field, if sufficiently large, can work against the classical trajectory and therefore counteract the end of inflation. In regions where this is the case the accelerated expansion of space continues at a higher rate. In parts of this region the process may replicate itself again and in this way may continue throughout all of time. Space and field are said to reproduce themselves. On the other hand, a mechanism that can occur in addition or independent of the latter, is so called vacuum tunneling. If the potential of the scalar field has several local minima, a semi-classical calculation suggests that within a spherical region, a bubble, the field can tunnel to another state. The respective tunneling rates depend on the potential difference and the shape of the potential between the states. Generally, the tunneling rate is exponentially suppressed, which means that the inflation lasts for a long time before tunneling takes place. The ongoing inflationary process effectively reduces local curvature, anistotropy and inhomogeneity, so that this property is known as the ‘cosmic no-hair conjecture’. For this reason cosmological considerations of the evolution of bubbles thus far almost entirely involved vacuum (de Sitter) backgrounds. However, new insights in the framework of string theory suggest high tunneling rates which allow for the possibility of bubble nucleation in non-vacuum dominated backgrounds. In this case the evolution of the bubble depends on the properties of the background spacetime. A deeper introduction in chapter 4 is followed by the presentation of the Lemaître-Tolman spacetime in chapter 5 which constitutes the background spacetime in the study of the effect of matter and inhomogeneity on the evolution of vacuum bubbles. In chapter 6 we explicitly describe the application of the ‘thin-shell’ formalism and the resulting system of equations. This is succeeded in chapter 7 by the detailed analysis of bubble evolution in various limits of the Lemaître-Tolman spacetime and a Robertson-Walker spacetime with a rapid phase transition. The central observations are that the presence of dust, at a fixed surface energy density, goes along with a smaller nucleation volume and possibly leads to a a collapse of the bubble. In an expanding background, the radially inhomogeneous dust profile is efficiently diluted so that there is essentially no effect on the evolution of the domain wall. This changes in a radially inhomogeneous curvature profile, positive curvature decelerates the expansion of the bubble. Moreover, we point out that the adopted approach does not allow for a treatment of a, physically expected, matter transfer so that the results are to be understood as preliminary under this caveat. In the second part of this thesis we consider potential observable consequences of bubble collisions in the cosmic microwave background radiation. The topological nature of the signal suggests the use of statistics that are well suited to quantify the morphological properties of the temperature fluctuations. In chapter 10 we present Minkowski Functionals (MFs) that exactly provide such statistics. The presented error analysis allows for a higher precision of numerical MFs in comparison to earlier methods. In chapter 12 we present the application of our algorithm to a Gaussian and a collision map. We motivate the expected MFs and extract their numerical counterparts. We find that our least-squares fitting procedure accurately reproduces an underlying signal only when a large number of realizations of maps are averaged over, while for a single WMAP and PLANCK resolution map, only when a highly prominent disk, with |δT| = 2√σG and ϑd = 40◦, we are able to recover the result. This is unfortunate, as it means that MF are intrinsically too noisy to be able to distinguish cold and hot spots in the CMB for small sizes.
In this study I investigate the role of Schwann cell and axon-derived trophic signals as modifiers of axonal integrity and sprouting in motoneuron disease and diabetic neuropathy (DNP). The first part of this thesis focuses on the role of the Schwann-cell-derived ciliary neurotrophic factor (CNTF) for compensatory sprouting in a mouse model for mild spinal muscular atrophy (SMA). In the second part, the role of the insulin-like growth factor 1 (IGF-1) and its binding protein 5 (IGFBP-5) is examined in the peripheral nerves of patients with DNP and in two corresponding mouse models. Proximal SMA is caused by homozygous loss or mutation of the SMN1 gene on human chromosome 5. The different forms of SMA can be divided into four groups, depending on the levels of SMN protein produced from a second SMN gene (SMN2) and the severity of the disease. Patients with milder forms of the disease, type III and type IV SMA, normally reach adulthood and regularly show enlargement of motor units, signifying the reinnervation of denervated muscle fibers. However, the underlying mechanisms are not understood. Smn+/- mice, a model of type III/IV SMA, are phenotypically normal, but they reveal progressive loss of motor neurons and denervation of motor endplates starting at 4 weeks of age. The progressive loss of spinal motor neurons reaches 50% at 12 months but muscle strength is not reduced. The first evidence for axonal sprouting as a compensatory mechanism in these animals was the more than 2-fold increase in amplitude of single motor unit action potentials (SMUAP) in the gastrocnemius muscle. Confocal analysis confirmed pronounced sprouting of innervating motor axons. As CNTF is highly expressed in Schwann cells and known to be involved in sprouting, its role for this compensatory sprouting response and the maintenance of muscle strength in Smn+/- mice was investigated. Deletion of CNTF in this mouse model results in reduced sprouting and decline of muscle strength in Smn+/- Cntf-/- mice. These findings indicate that CNTF is necessary for a sprouting response and thus enhances the size of motor units in skeletal muscles of Smn+/- mice. DNP afflicting motor and sensory nerve fibers is a major complication in diabetes mellitus. The underlying cellular mechanisms of motor axon degeneration are poorly understood. IGFBP-5, an inhibitory binding protein for IGF-1, is highly upregulated in peripheral nerves in patients with DNP. The study investigates the pathogenic relevance of this finding in transgenic mice overexpressing IGFBP-5 in motor axons. These mice develop motor axonopathy similar to that seen in DNP. Motor axon degeneration is also observed in mice in which the IGF-1 receptor (IGF-1R) was conditionally depleted in motoneurons, indicating that reduced activity of IGF-1 on IGF-1R in motoneurons is responsible for the observed effect. These data provide evidence that elevated expression of IGFBP-5 in diabetic nerves reduces the availability of IGF-1 for IGF-1R on motor axons leading to progressive neurodegeneration, and thus offers novel treatment strategies.
Small-angle X-ray scattering (SAXS) is a universal low-resolution method to study proteins in solution and to analyze structural changes in response to variations of conditions (pH, temperature, ionic strength etc). SAXS is hardly limited by the particle size, being applicable to the smallest proteins and to huge macromolecular machines like ribosomes and viruses. SAXS experiments are usually fast and require a moderate amount of purified material. Traditionally, SAXS is employed to study the size and shape of globular proteins, but recent developments have made it possible to quantitatively characterize the structure and structural transitions of metastable systems, e.g. partially or completely unfolded proteins. In the absence of complementary information, low-resolution macromolecular shapes can be reconstructed ab initio and overall characteristics of the systems can be extracted. If a high or low-resolution structure or a predicted model is available, it can be validated against the experimental SAXS data. If the measured sample is polydisperse, the oligomeric state and/or oligomeric composition in solution can be determined. One of the most important approaches for macromolecular complexes is a combined ab initio/rigid body modeling, when the structures (either complete or partial) of individual subunits are available and SAXS data is employed to build the entire complex. Moreover, this method can be effectively combined with information from other structural, computational and biochemical methods. All the above approaches are covered in a comprehensive program suite ATSAS for SAXS data analysis, which has been developed at the EMBL-Hamburg. In order to meet the growing demands of the structural biology community, methods for SAXS data analysis must be further developed. This thesis describes the development of two new modules, RANLOGS and EM2DAM, which became part of ATSAS suite. The former program can be employed for constructing libraries of linkers and loops de novo and became a part of a combined ab initio/rigid body modeling program CORAL. EM2DAM can be employed to convert electron microscopy maps to bead models, which can be used for modeling or structure validation. Moreover, the programs CRYSOL and CRYSON, for computing X-ray and neutron scattering patterns from atomic models, respectively, were refurbished to work faster and new options were added to them. Two programs, to be contributed to future releases of the ATSAS package, were also developed. The first program generates a large pool of possible models using rigid body modeling program SASREF, selects and refines models with lowest discrepancy to experimental SAXS data using a docking program HADDOCK. The second program refines binary protein-protein complexes using the SAXS data and the high-resolution models of unbound subunits. Some results and conclusions from this work are presented here. The developed approaches detailed in this thesis, together with existing ATSAS modules were additionally employed in a number of collaborative projects. New insights into the “structural memory” of natively unfolded tau protein were gained and supramodular structure of RhoA-specific guanidine nucleotide exchange factor was reconstructed. Moreover, high resolution structures of several hematopoietic cytokine-receptor complexes were validated and re-modeled using the SAXS data. Important information about the oligomeric state of yeast frataxin in solution was derived from the scattering patterns recorded under different conditions and its flexibility was quantitatively characterized using the Ensemble Optimization Method (EOM).
Molecular modelling and simulation are powerful methods in providing important in-formation on different biological systems to elucidate their structural and functional proper-ties, which cannot be determined in experiment. These methods are applied to analyse versa-tile biological systems: lipid membrane bilayers stabilized by an intercalated single wall carbon nanotube and retroviral proteins such as HIV protease and integrase. HIV-1 integrase has nuclear localization signals (NLS) which play a crucial role in nuclear import of viral preintegration complex (PIC). However, the detailed mechanisms of PIC formation and its nuclear transport are not known. Previously it was shown that NLSs bind to the cell transport machinery e.g. proteins of nuclear pore complex such as transportins. I investigated the interaction of this viral protein HIV-1 integrase with proteins of the nuclear pore complex such as transportin-SR2 (Shityakov et al., 2010). I showed that the transportin-SR2 in nuclear import is required due to its interaction with the HIV-1 integrase. I analyzed key domain interaction, and hydrogen bond formation in transportin-SR2. These results were discussed in comparison to other retroviral species such as foamy viruses to better understand this specific and efficient retroviral trafficking route. The retroviral nuclear import was next analyzed in experiments regarding the retroviral ability to infect nondividing cells. To accomplish the gene transfer task successfully, ret-roviruses must efficiently transduce different cell cultures at different phases of cell cycle. However, promising and safe foamy viral vectors used for gene transfer are unable to effi-ciently infect quiescent cells. This drawback was due to their inability to create a preintegra-tion complex (PIC) for nuclear import of retroviral DNA. On the contrary, the lentiviral vec-tors are not dependant on cell cycle. In the course of reverse transcription the polypurine tract (PPT) is believed to be crucial for PIC formation. In this thesis, I compared the transduction frequencies of PPT modified FV vectors with lentiviral vectors in nondividing and dividing alveolar basal epithelial cells from human adenocarcinoma (A549) by using molecular cloning, transfection and transduction techniques and several other methods. In contrast to lentiviral vectors, FV vectors were not able to effi-ciently transduce nondividing cell (Shityakov and Rethwilm, unpublished data). Despite the findings, which support the use of FV vectors as a safe and efficient alternative to lentiviral vectors, major limitation in terms of foamy-based retroviral vector gene transfer in quiescent cells still remains. Many attempts have been made recently to search for the potential molecules as pos-sible drug candidates to treat HIV infection for over decades now. These molecules can be retrieved from chemical libraries or can be designed on a computer screen and then synthe-sized in a laboratory. Most notably, one could use the computerized structure as a reference to determine the types of molecules that might block the enzyme. Such structure-based drug design strategies have the potential to save off years and millions of dollars compared to a more traditional trial-and-error drug development process. After the crystal structure of the HIV-encoded protease enzyme had been elucidated, computer-aided drug design played a pivotal role in the development of new compounds that inhibit this enzyme which is responsible for HIV maturation and infectivity. Promising repre-sentatives of these compounds have recently found their way to patients. Protease inhibitors show a powerful sustained suppression of HIV-1 replication, especially when used in combi-nation therapy regimens. However, these drugs are becoming less effective to more resistant HIV strains due to multiple mutations in the retroviral proteases. In computational drug design I used molecular modelling methods such as lead ex-pansion algorithm (Tripos®) to create a virtual library of compounds with different binding affinities to protease binding site. In addition, I heavily applied computer assisted combinato-rial chemistry approaches to design and optimize virtual libraries of protease inhibitors and performed in silico screening and pharmacophore-similarity scoring of these drug candidates. Further computational analyses revealed one unique compound with different protease bind-ing ability from the initial hit and its role for possible new class of protease inhibitors is dis-cussed (Shityakov and Dandekar, 2009). A number of atomistic models were developed to elucidate the nanotube behaviour in lipid bilayers. However, none of them provided useful information for CNT effect upon the lipid membrane bilayer for implementing all-atom models that will allow us to calculate the deviations of lipid molecules from CNT with atomistic precision. Unfortunately, the direct experimental investigation of nanotube behaviour in lipid bilayer remains quite a tricky prob-lem opening the door before the molecular simulation techniques. In this regard, more de-tailed multi-scale simulations are needed to clearly understand the stabilization characteristics of CNTs in hydrophobic environment. The phenomenon of an intercalated single-wall carbon nanotube in the center of lipid membrane was extensively studied and analyzed. The root mean square deviation and root mean square fluctuation functions were calculated in order to measure stability of lipid mem-branes. The results indicated that an intercalated carbon nanotube restrains the conformational freedom of adjacent lipids and hence has an impact on the membrane stabilization dynamics (Shityakov and Dandekar, 2011). On the other hand, different lipid membranes may have dissimilarities due to the differing abilities to create a bridge formation between the adherent lipid molecules. The results derived from this thesis will help to develop stable nanobiocom-posites for construction of novel biomaterials and delivery of various biomolecules for medi-cine and biology.
Die Chlorophylle stellen in der Natur die wichtigsten Pigmente dar, weil sie verantwortlich für die Photosynthese sind und hierbei vielfältige Funktionen wahrnehmen, die sich aus ihrer Selbstassemblierung sowie den vorteilhaften optischen und Redox-Eigenschaften ergeben. Die in dieser Arbeit untersuchten semisynthetischen Zinkchlorine stellen Modellverbindungen des natürlichen Bacteriochlorophylls c (BChl c) der Lichtsammelsysteme (light-harvesting: LH) in Chlorosomen von Bakterien, jedoch ohne Proteingerüst, dar. Die entscheidenden Vorteile dieser Zinkchlorine (ZnChl) gegenüber den natürlichen BChls bestehen im einfachen semisynthetischen Zugang ausgehend von Chlorophyll a (Chl a), ihrer gesteigerten chemischen Stabilität sowie der Möglichkeit ihre Selbstassemblierung durch gezielte chemische Modifizierung der Seitenketten in der Peripherie zu steuern. Während bereits mehrfach über die vielversprechenden Redox- und excitonischen Eigenschaften von Aggregaten von ZnChl und natürlichem BChl c und den damit verbundene Voraussetzungen für Excitontransport über große Distanzen berichtet wurde, sind die Ladungstransporteigenschaften von Aggregaten der biomimetischen ZnChl bis heute unerforscht. Die vorliegende Arbeit beschäftigt sich mit der Aufklärung der Struktur von Aggregaten einer Vielzahl von semisynthetischen Zinkchlorophyllderivaten im Feststoff, in Lösung und auf Oberflächen durch die Kombination verschiedenster spektroskopischer, kristallographischer und mikroskopischer Techniken an die sich Untersuchungen zum Ladungstransport in den Aggregaten anschließen. Schema 1 zeigt die verschiedenen, in dieser Arbeit synthetisierten ZnChls, die entweder mit einer Hydroxy- oder Methoxygruppe in der 31-Position funktionalisiert sind sowie Substituenten unterschiedlicher Art, Länge und Verzweigung an der Benzylestergruppe in 172-Position tragen.Die Packung dieser Farbstoffe hängt entscheidend von ihrer chemischen Struktur ab. Während die ZnChls 1a, 2a, 3 mit 31-Hydroxygruppe und Alkylseitenketten (Dodecyl bzw. Oligoethylenglykol) gut lösliche stabförmige Aggregate bilden, lagern sich die analogen Verbindungen mit 31-Methoxygruppe (1b, 2b) zu Stapeln in Lösung und auf Oberflächen zusammen. Diese supramolekularen Polymere wurden im Detail in Kapitel 3 mit Hilfe von UV/Vis- und CD-Spektroskopie (circular dichroism: CD) sowie dynamische Lichtstreuung (dynamic light scattering: DLS) untersucht. Darüber hinaus lieferten temperaturabhängige UV/Vis- in Kombination mit DLS-Messungen wertvolle Informationen über die Aggregationsprozess dieser beiden Sorten von Aggregaten. Während sich die ZnChl 1a mit 31 Hydroxygruppe entsprechend dem isodesmischen Modell zu röhrenförmigen Aggregaten zusammenlagern, bilden sich die stapelförmigen Aggregate von 1b nach einem kooperativen Keimbildungs-Wachstums-Mechanismus (nucleation-elongation mechanism). Detaillierte elektronenmikroskopische Studien lieferten erstmals überzeugende Beweise für röhrenförmige Nanostrukturen der Aggregate des wasserlöslichen 31-Hydroxy Zinkchlorin 3. Die gemessenen Durchmesser der Röhren von ~ 5-6 nm dieser Aggregate liegen in hervorragender Übereinstimmung mit den Elektronenmikroskopie-Daten von BChl c Stabaggregaten in Chlorosomen (Chloroflexus aurantiacus, Durchmesser ~ 5-6 nm) und entsprechen damit dem von Holzwarth und Schaffner postulierten röhrenförmigen Modell... Im Einklang mit ihren hoch geordneten, robusten Strukturen, die sich eindimensional in einer Größenordnung von Mikrometeren erstrecken, sowie ihrer Fähigkeit zum effizienten Ladungs-trägertransport stellen diese selbstassemblierten Nanoröhren von ZnChls vielversprechende Ausgangsmaterialien für die Fertigung supramolekularer elektronischer Bauteile dar. Wissenschaftliche Bemühungen einige dieser Moleküle und ihre entsprechenden supramolekularen Polymere für die Fertigung von (opto-)elektronischen Bauteilen wie organischen Feldeffekttransistoren zu benutzten, stellen lohnende Aufgaben für die Zukunft dar...
Purpose:
The biologic relevance of human connective tissue growth factor (hCTGF) for primary human tenon fibroblasts (HTFs) was investigated by RNA expression profiling using affymetrix (TM) oligonucleotide array technology to identify genes that are regulated by hCTGF.
Methods:
Recombinant hCTGF was expressed in HEK293T cells and purified by affinity and gel chromatography. Specificity and biologic activity of hCTGF was confirmed by biosensor interaction analysis and proliferation assays. For RNA expression profiling HTFs were stimulated with hCTGF for 48h and analyzed using affymetrix (TM) oligonucleotide array technology. Results were validated by real time RT-PCR.
Results:
hCTGF induces various groups of genes responsible for a wound healing and inflammatory response in HTFs. A new subset of CTGF inducible inflammatory genes was discovered (e.g., chemokine [C-X-C motif] ligand 1 [CXCL1], chemokine [C-X-C motif] ligand 6 [CXCL6], interleukin 6 [IL6], and interleukin 8 [IL8]). We also identified genes that can transmit the known biologic functions initiated by CTGF such as proliferation and extracellular matrix remodelling. Of special interest is a group of genes, e.g., osteoglycin (OGN) and osteomodulin (OMD), which are known to play a key role in osteoblast biology.
Conclusions:
This study specifies the important role of hCTGF for primary tenon fibroblast function. The RNA expression profile yields new insights into the relevance of hCTGF in influencing biologic processes like wound healing, inflammation, proliferation, and extracellular matrix remodelling in vitro via transcriptional regulation of specific genes. The results suggest that CTGF potentially acts as a modulating factor in inflammatory and wound healing response in fibroblasts of the human eye.
Immunotherapeutic strategies may be a treatment option in patients with refractory acute myelogenous leukemia (AML) or, in cases of complete remission after conventional therapy regimens, may help to reduce disease recurrence or delay time to progression. Evidence suggests a key role of dendritic cells (DCs) in cancer immunotherapy due to their capacity to present tumour antigens to effector cells. We generated cytokine-induced killer (CIK) cells from healthy donors and examined their responses in vitro in an LDH release assay against three cell lines and allogeneic HLA non-matched blasts from three patients with de novo AML after coincubation with autologous peripheral blood monocyte-derived DCs. Although DCs were unable to enhance CIK cell effects against all three cell lines tested, the cytotoxic activity against the patients’ AML cells increased after coculture with mature DCs, which was significant in two of three patients. However, neither prior pulsing of the DCs with blast cell lysates nor with leukemic cell-derived total RNA further enhanced the lytic capacity of the CIK cells. On the contrary, pulsing reduced or even reversed the cytotoxic activity of the effector cells. This decrease of allogeneic cytotoxicity led us to conclude that monocyte-derived DCs may be useful in autologous or allogeneic vaccine strategies for the treatment of AML or in priming donor lymphocytes in vitro, but unfractionated antigens as pulsing agents may have inhibitory effects on T cell efficiency and their employment in immunotherapeutic strategies for AML seems questionable.
This study aimed to optimise the application, efficiency and interpretability of quasi-3D resistivity imaging for investigating the heterogeneous permafrost distribution at mountain sites by a systematic forward modelling approach. A three dimensional geocryologic model, representative for most mountain permafrost settings, was developed. Based on this geocryologic model quasi-3D models were generated by collating synthetic orthogonal 2D arrays, demonstrating the effects of array types and electrode spacing on resolution and interpretability of the inversion results. The effects of minimising the number of 2D arrays per quasi-3D grid were tested by enlarging the spacing between adjacent lines and by reducing the number of perpendicular tie lines with regard to model resolution and loss of information value. Synthetic and measured quasi-3D models were investigated with regard to the lateral and vertical resolution, reliability of inverted resistivity values, the possibility of a quantitative interpretation of resistivities and the response of the inversion process on the validity of quasi-3D models. Results show that setups using orthogonal 2D arrays with electrode spacings of 2 m and 3 m are capable of delineating lateral heterogeneity with high accuracy and also deliver reliable data on active layer thickness. Detection of permafrost thickness, especially if the permafrost base is close to the penetration depth of the setups, and the reliability of absolute resistivity values emerged to be a weakness of the method. Quasi-3D imaging has proven to be a promising tool for investigating permafrost in mountain environments especially for delineating the often small-scale permafrost heterogeneity, and therefore provides an enhanced possibility for aligning permafrost distribution with site specific surface properties and morphological settings.
In the mammalian host, the Trypanosoma brucei cell surface is covered with a densely packed protein coat of a single protein, the variant surface glycoprotein (VSG). The VSG is believed to shield invariant surface proteins from host antibodies but there is limited information on how far antibodies can penetrate into the VSG monolayer. Here, the VSG surface coat was probed to determine whether it acts as a barrier to binding of antibodies to the membrane proximal VSG C-terminal domain. The binding of C-terminal domain antibodies to VSG221 or VSG118 was compared with antibodies recognising the cognate whole VSGs. The C-terminal VSG domain was inaccessible to antibodies on live cells but not on fixed cells. This provides further evidence that the VSG coat acts as a barrier and protects the cell from antibodies that would otherwise bind to some of the other externally disposed proteins.
The subject of this thesis are mathematical programs with complementarity conditions (MPCC). At first, an economic example of this problem class is analyzed, the problem of effort maximization in asymmetric n-person contest games. While an analytical solution for this special problem could be derived, this is not possible in general for MPCCs. Therefore, optimality conditions which might be used for numerical approaches where considered next. More precisely, a Fritz-John result for MPCCs with stronger properties than those known so far was derived together with some new constraint qualifications and subsequently used to prove an exact penalty result. Finally, to solve MPCCs numerically, the so called relaxation approach was used. Besides improving the results for existing relaxation methods, a new relaxation with strong convergence properties was suggested and a numerical comparison of all methods based on the MacMPEC collection conducted.
Channelrhodopsin-2 (ChR2) is widely used for rapid photodepolarization of neurons, yet, as it requires high-intensity blue light for activation, it is not suited for long-term in vivo applications, e. g. for manipulations of behavior, or photoactivation of neurons during development. We used "slow" ChR2 variants with mutations in the C128 residue, that exhibit delayed off-kinetics and increased light sensitivity in Caenorhabditis elegans. Following a 1 s light pulse, we could photodepolarize neurons and muscles for minutes (and with repeated brief stimulation, up to days) with low-intensity light. Photoactivation of ChR2(C128S) in command interneurons elicited long-lasting alterations in locomotion. Finally, we could optically induce profound changes in animal development: Long-term photoactivation of ASJ neurons, which regulate larval growth, bypassed the constitutive entry into the "dauer" larval state in daf-11 mutants. These lack a guanylyl cyclase, which possibly renders ASJ neurons hyperpolarized. Furthermore, photostimulated ASJ neurons could acutely trigger dauer-exit. Thus, slow ChR2s can be employed to long-term photoactivate behavior and to trigger alternative animal development.
Dendritic cell tumors are extremely rare neoplasms arising from antigen-presenting cells of the immune system. We report a case of a 69-year-old man with an unremarkable medical history who presented with a 2-months history of a gradually enlarging painless, firm, mobile, 2 × 2-cm swelling at the caudal pole of the left parotid gland without systemic symptoms. Histologically, the tumor consisted of a spindle cell proliferation in an intraparotideal lymph node. Based on the histopathologic, immunohistochemical and electron microscopic findings, a dendritic cell tumor, not otherwise specified (NOS) in an intraparotideal lymph node was diagnosed. The patient underwent complete tumor resection, and is currently free of disease, 2 years after surgery. These extremely rare tumors must be distinguished from other more common tumors in the salivary glands. Awareness that dendritic cell tumors may occur in this localization, careful histologic evaluation and ancillary immunohistochemical and electron microscopical analyses should allow for recognition of this entity. Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1614859498581601.
The synaptonemal complex (SC) is a proteinaceous, meiosis-specific structure that is highly conserved in evolution. During meiosis, the SC mediates synapsis of homologous chromosomes. It is essential for proper recombination and segregation of homologous chromosomes, and therefore for genome haploidization. Mutations in human SC genes can cause infertility. In order to gain a better understanding of the process of SC assembly in a model system that would be relevant for humans, we are investigating meiosis in mice. Here, we report on a newly identified component of the murine SC, which we named SYCE3. SYCE3 is strongly conserved among mammals and localizes to the central element (CE) of the SC. By generating a Syce3 knockout mouse, we found that SYCE3 is required for fertility in both sexes. Loss of SYCE3 blocks synapsis initiation and results in meiotic arrest. In the absence of SYCE3, initiation of meiotic recombination appears to be normal, but its progression is severely impaired resulting in complete absence of MLH1 foci, which are presumed markers of crossovers in wild-type meiocytes. In the process of SC assembly, SYCE3 is required downstream of transverse filament protein SYCP1, but upstream of the other previously described CE–specific proteins. We conclude that SYCE3 enables chromosome loading of the other CE–specific proteins, which in turn would promote synapsis between homologous chromosomes.
Characterisation of Metalloprotease-mediated EGFR Signal Transactivation after GPCR Stimulation
(2011)
In the context of metalloprotease-mediated transactivation of the epidermal growth factor receptor, different monoclonal antibodies against ADAM17 / TACE were characterized for their ability to block the sheddase. Activity of some of them was observed at doses between 2µg/mL and 10µg/mL. Kinetic analyses showed their activity starting at around 30 minutes. In cellular assays performed with the antibodies, especially upon treatment of cells with sphingosine-1-phosphate a reduction in proliferation was observed with some candidates. Moreover this study provides potential new roles for ß-Arrestins. Their involvement in the triple membrane-passing signal pathway of EGFR transactivation was shown. Furthermore, in overexpressing cellular model systems, an interaction between ADAM17 and ß-Arrestin1 could be observed. Detailed analysis discovered that phosphorylation of ß-Arrestin1 is crucial for this interaction. Additionally, the novel mechanism of UV-induced EGFR transactivation was extended to squamous cell carcinoma. The mechanism happens in a dose dependent manner and requires a metalloprotease to shed the proligand Amphiregulin. The involvement of both ADAM9 and ADAM17, being the metalloproteases responsible for this cleavage, was shown for SCC9 cells.
Background:
A substantial amount of data has been accumulated supporting the important role of genomic islands (GEIs) - including pathogenicity islands (PAIs) - in bacterial genome plasticity and the evolution of bacterial pathogens. Their instability and the high level sequence similarity of different (partial) islands suggest an exchange of PAIs between strains of the same or even different bacterial species by horizontal gene transfer (HGT). Transfer events of archetypal large genomic islands of enterobacteria which often lack genes required for mobilisation or transfer have been rarely investigated so far.
Results:
To study mobilisation of such large genomic regions in prototypic uropathogenic E. coli (UPEC) strain 536, PAI II(536) was supplemented with the mob(RP4) region, an origin of replication (oriV(R6K)), an origin of transfer (oriT(RP4)) and a chloramphenicol resistance selection marker. In the presence of helper plasmid RP4, conjugative transfer of the 107-kb PAI II(536) construct occured from strain 536 into an E. coli K-12 recipient. In transconjugants, PAI II(536) existed either as a cytoplasmic circular intermediate (CI) or integrated site-specifically into the recipient's chromosome at the leuX tRNA gene. This locus is the chromosomal integration site of PAI II(536) in UPEC strain 536. From the E. coli K-12 recipient, the chromosomal PAI II(536) construct as well as the CIs could be successfully remobilised and inserted into leuX in a PAI II(536) deletion mutant of E. coli 536.
Conclusions:
Our results corroborate that mobilisation and conjugal transfer may contribute to evolution of bacterial pathogens through horizontal transfer of large chromosomal regions such as PAIs. Stabilisation of these mobile genetic elements in the bacterial chromosome result from selective loss of mobilisation and transfer functions of genomic islands.
This study was conducted to determine the influence of different stress factors on the honeybee Apis mellifera. The investigation was motivated by previous experiments that suggested the existence of an unspecific defense mechanism causing a generalized change of flight behavior after the onset of different diseases. This mechanism is thought to impede the ability of flight bees to return to their respective colonies thereby removing the disease from the colony over time. During the last years, the existence of such a “suicidal behavior” was supported by further studies. Thus, an unnoticed, potentially highly effective defense mechanism of social insects was revealed whose spectrum of activity and physiological basics require further investigation. Suggesting that the reaction by the bees is unspecific to different diseases as well as to other potential stress factors, this study was designed to investigate the influence of pathogens, insecticides, and different brood rearing temperatures on different parameters like lifespan, foraging activity, and foraging trip duration of worker bees.
The present work reviews the experimental literature on the acute effects of alcohol on human behaviour related to driving performance. A meta-analysis was conducted which includes studies published between 1954 and 2007 in order to provide a comprehensive knowledge of the substance alcohol. 450 studies reporting 5,300 findings were selected from over 12,000 references after applying certain in- and exclusion criteria. Thus, the present meta-analysis comprises far more studies than reviews on alcohol up to now. In the selected studies, different performance tests were conducted which were relevant for driving. The classification system used in this work assigns these tests to eight categories. The main categories consist of several sub categories classifying the tasks more precisely. The main categories were: (1) visual functions, (2) attention (including vigilance), (3) divided attention, (4) en-/decoding (including information processing and memory), (5) reaction time (including simple reaction time and choice reaction time), (6) psychomotor skills, (7) tracking and (8) driving. In addition to the performance aspect, the classification system takes into account mood and social behaviour variables related to driving safety like tiredness or aggression. Following the evaluation method of vote-counting, the number of significant findings and the number of non-significant findings were summarised per blood alcohol concentration (BAC) group. Thereby, a quantitative estimation of the effects of alcohol depending on the BAC was established, the so-called impairment function, which shows the percentage of significantly impaired findings. In order to provide a general overview of alcohol effects on driving-related performance, a global impairment function was established by aggregating all performance findings. The function is nearly linear with about 30% significant findings at a BAC of 0.05% and 50% significant findings at a BAC of 0.08%. In addition, more specific impairment functions considering only the findings of the single behavioural categories were calculated. The results revealed that impairment depends not only on the BAC, but also clearly differs between most of the performance categories. Tracking and driving performance were most affected by alcohol with impairment beginning at very low BACs of 0.02%. Also psychomotor skills were considerably affected by rather low BACs. Impairment of visual functions and information processing occurred at BACs of 0.04% and increased substantially with higher BACs. Impairment in memory tests could be found with very low BACs of 0.02%, but varied depending on the kind of memory. Performance decrements in divided attention tests could also be found with very low BACs in some studies. Attention started to be impaired at 0.04% BAC, but – as in vigilance tasks – considerable impairment only occurred at higher BACs. Choice reaction time was affected at lower BACs than simple reaction time, which was – together with the critical flicker fusion frequency – the least sensitive parameter to the effects of alcohol. To conclude, most skills which are relevant for the safe operation of a vehicle are clearly impaired by BACs of 0.05%, with motor functions being more affected than cognitive functions and complex tasks more than simple tasks. Generally, the results provided no evidence of a threshold effect for alcohol. There was no driving-related performance category for which a sudden transition from unimpaired to impaired occurred at a particular BAC level. In addition, a comparison was made between the present meta-analysis and two reviews of Moskowitz (Moskowitz & Fiorentino, 2000; Moskowitz & Robinson, 1988). Moskowitz reported much lower BACs at which performance was impaired. The reasons for this discrepancy lies in a different way to review scientific findings. On the one hand, Moskowitz focused on significant findings when selecting studies and findings for his reviews. On the other hand, the evaluation method used by Moskowitz ignored non-significant findings and counted each study once at the lowest BAC for which impairment was found. Those non-significant findings are as important as the significant ones in order to determine thresholds of impairment. Therefore, in contrast to Moskowitz, the present work describes the effects of alcohol with functions considering also the non-significant findings. The significance of the non-significant is emphasized with respect to the selection procedure as well as to the evaluation method.
Several studies report autoantibody signatures in cancer. The majority of these studies analyzed adult tumors and compared the seroreactivity pattern of tumor patients with the pattern in healthy controls. Here, we compared the autoimmune response in patients with neuroblastoma and patients with Wilms tumor representing two different childhood tumors. We were able to differentiate untreated neuroblastoma patients from untreated Wilms tumor patients with an accuracy of 86.8%, a sensitivity of 87.0% and a specificity of 86.7%. The separation of treated neuroblastoma patients from treated Wilms tumor patients' yielded comparable results with an accuracy of 83.8%. We furthermore identified the antigens that contribute most to the differentiation between both tumor types. The analysis of these antigens revealed that neuroblastoma was considerably more immunogenic than Wilms tumor. The reported antigens have not been found to be relevant for comparative analyses between other tumors and controls. In summary, neuroblastoma appears as a highly immunogenic tumor as demonstrated by the extended number of antigens that separate this tumor from Wilms tumor.
The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promoter element and no consensus Shine-Dalgarno sequence. Moreover, 14% of all mRNAs are leaderless and 13% of them have unusually long 5'-UTRs. Northern blot analyses confirmed 16 intergenic small RNAs and seven cis-encoded antisense RNAs in Xcv. Expression of eight intergenic transcripts was controlled by HrpG and HrpX, key regulators of the Xcv type III secretion system. More detailed characterization identified sX12 as a small RNA that controls virulence of Xcv by affecting the interaction of the pathogen and its host plants. The transcriptional landscape of Xcv is unexpectedly complex, featuring abundant antisense transcripts, alternative TSSs and clade-specific small RNAs.
Background: Tumor patients exhibit an increased peripheral demand of fatty acids and protein. Contrarily, tumors utilize glucose as their main source of energy supply. Thus, a diet supplying the cancer patient with sufficient fat and protein for his demands while restricting the carbohydrates (CHO) tumors thrive on, could be a helpful strategy in improving the patients’ situation. A ketogenic diet (KD) fulfills these requirements. Therefore, we performed a pilot study to investigate the feasibility of a KD and its influence on the quality of life of patients with advanced metastatic tumors. Methods: Sixteen patients with advanced metastatic tumors and no conventional therapeutic options participated in the study. The patients were instructed to follow a KD (less than 70 g CHO per day) with normal groceries and were provided with a supply of food additives to mix a protein/fat shake to simplify the 3-month intervention period. Quality of life [assessed by EORTC QLQ-C30 (version 2)], serum and general health parameters were determined at baseline, after every two weeks of follow-up, or after drop out. The effect of dietary change on metabolism was monitored daily by measuring urinary ketone bodies. Results: One patient did not tolerate the diet and dropped out within 3 days. Among those who tolerated the diet, two patients died early, one stopped after 2 weeks due to personal reasons, one felt unable to stick to the diet after 4 weeks, one stopped after 6 and two stopped after 7 and 8 weeks due to progress of the disease, one had to discontinue after 6 weeks to resume chemotherapy and five completed the 3 month intervention period. These five and the one who resumed chemotherapy after 6 weeks report an improved emotional functioning and less insomnia, while several other parameters of quality of life remained stable or worsened, reflecting their very advanced disease. Except for temporary constipation and fatigue, we found no severe adverse side effects, especially no changes in cholesterol or blood lipids. Conclusions: These pilot data suggest that a KD is suitable for even advanced cancer patients. It has no severe side effects and might improve aspects of quality of life and blood parameters in some patients with advanced metastatic tumors.
The field of small satellite formations and constellations attracted growing attention, based on recent advances in small satellite engineering. The utilization of distributed space systems allows the realization of innovative applications and will enable improved temporal and spatial resolution in observation scenarios. On the other side, this new paradigm imposes a variety of research challenges. In this monograph new networking concepts for space missions are presented, using networks of ground stations. The developed approaches combine ground station resources in a coordinated way to achieve more robust and efficient communication links. Within this thesis, the following topics were elaborated to improve the performance in distributed space missions: Appropriate scheduling of contact windows in a distributed ground system is a necessary process to avoid low utilization of ground stations. The theoretical basis for the novel concept of redundant scheduling was elaborated in detail. Additionally to the presented algorithm was a scheduling system implemented, its performance was tested extensively with real world scheduling problems. In the scope of data management, a system was developed which autonomously synchronizes data frames in ground station networks and uses this information to detect and correct transmission errors. The system was validated with hardware in the loop experiments, demonstrating the benefits of the developed approach.
Currently, we observe a strong growth of services and applications, which use the Internet for data transport. However, the network requirements of these applications differ significantly. This makes network management difficult, since it complicated to separate network flows into application classes without inspecting application layer data. Network virtualization is a promising solution to this problem. It enables running different virtual network on the same physical substrate. Separating networks based on the service supported within allows controlling each network according to the specific needs of the application. The aim of such a network control is to optimize the user perceived quality as well as the cost efficiency of the data transport. Furthermore, network virtualization abstracts the network functionality from the underlying implementation and facilitates the split of the currently tightly integrated roles of Internet Service Provider and network owner. Additionally, network virtualization guarantees that different virtual networks run on the same physical substrate do not interfere with each other. This thesis discusses different aspects of the network virtualization topic. It is focused on how to manage and control a virtual network to guarantee the best Quality of Experience for the user. Therefore, a top-down approach is chosen. Starting with use cases of virtual networks, a possible architecture is derived and current implementation options based on hardware virtualization are explored. In the following, this thesis focuses on assessing the Quality of Experience perceived by the user and how it can be optimized on application layer. Furthermore, options for measuring and monitoring significant network parameters of virtual networks are considered.
Dilated cardiomyopathy (DCM) represents an important subgroup of patients suffering from heart failure. The disease is supposed to be associated with autoimmune mechanisms in about one third of the cases. In the latter patients functionally active conformational autoantibodies directed against the second extracellular loop of the β1-adrenergic receptor (AR, β1ECII-aabs) have been detected. Such antibodies chronically stimulate the β1-AR thereby inducing the adrenergic signaling cascade in cardiomyocytes, which, in the long run, contributes to heart failure progression. We analyzed the production of cAMP after aab-mediated β1-AR activation in vitro using a fluorescence resonance energy transfer (FRET) assay. This assay is based on HEK293 cells stably expressing human β1-AR as well as the cAMP-sensor Epac1-camps. The assay showed a concentration-dependent increase in intracellular cAMP upon stimulation with the full agonist (-) isoproterenol. This response was comparable to results obtained in isolated adult murine cardiomyocytes and was partially blockable by a selective β1-AR antagonist. In the same assay poly- and monoclonal anti-β1ECII-abs (induced in different animals) could activate the adrenergic signaling cascade, whereas isotypic control abs had no effect on intracellular cAMP levels. Using the same method, we were able to detect functionally activating aabs in the serum of heart failure patients with ischemic and hypertensive heart disease as well as patients with DCM, but not in sera of healthy control subjects. In patients with DCM we observed an inverse correlation between the stimulatory potential of anti-β1-aabs and left ventricular pump function. To adopt this assay for the detection of functionally activating anti-β1ECII-aabs in clinical routine we attempted to establish an automated large-scale approach. Neither flow cytometry nor FRET detection with a fluorescence plate reader provided an acceptable signal-to-noise ratio. It was possible to detect (-) isoproterenol in a concentration-dependent manner using two different FRET multiwell microscopes. However, due to focus problems large-scale detection of activating anti-β1ECII-abs could not be implemented. Neutralization of anti-β1-aabs with the corresponding epitope-mimicking peptides is a possible therapeutic approach to treat aab-associated autoimmune DCM. Using our FRET assay we could demonstrate a reduction in the stimulatory potential of anti-β1ECII-abs after in vitro incubation with β1ECII-mimicking peptides. Cyclic (and to a lesser extent linear) peptides in 40-fold molar excess acted as efficient ab-scavengers in vitro. Intravenously injected cyclic peptides in a rat model of DCM also neutralized functionally active anti-β1ECII-abs efficiently in vivo. For a detailed analysis of the receptor-epitope targeted by anti-β1ECII-abs we used sequentially alanine-mutated β1ECII-mimicking cyclic peptides. Our data revealed that the disulfide bridge between the cysteine residues C209 and C215 of the human β1-AR appears essential for the formation of the ab-epitope. Substitution of further amino acids relevant for ab-binding in the cyclic scavenger peptide by alanine reduced its affinity to the ab and the receptor-activating potential was blocked less efficiently. In contrast, the non-mutant cyclic peptide almost completely blocked ab-induced receptor activation. Using this ala-scan approach we were able to identify a “NDPK”-epitope as essential for ab binding to the β1ECII. In summary, neutralization of conformational activating anti-β1ECII-(a)abs by cyclic peptides is a plausible therapeutic concept in heart failure that should be further exploited based on the here presented data.
Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants.
Background:
The probiotic Escherichia coli strain Nissle 1917 (EcN) has been shown to interfere in a human in vitro model with the invasion of several bacterial pathogens into epithelial cells, but the underlying molecular mechanisms are not known.
Methodology/Principal Findings:
In this study, we investigated the inhibitory effects of EcN on Salmonella Typhimurium invasion of porcine intestinal epithelial cells, focusing on EcN effects on the various stages of Salmonella infection including intracellular and extracellular Salmonella growth rates, virulence gene regulation, and adhesion. We show that EcN affects the initial Salmonella invasion steps by modulating Salmonella virulence gene regulation and Salmonella SiiE-mediated adhesion, but not extra-and intracellular Salmonella growth. However, the inhibitory activity of EcN against Salmonella invasion always correlated with EcN adhesion capacities. EcN mutants defective in the expression of F1C fimbriae and flagellae were less adherent and less inhibitory toward Salmonella invasion. Another E. coli strain expressing F1C fimbriae was also adherent to IPEC-J2 cells, and was similarly inhibitory against Salmonella invasion like EcN.
Conclusions:
We propose that EcN affects Salmonella adhesion through secretory components. This mechanism appears to be common to many E. coli strains, with strong adherence being a prerequisite for an effective reduction of SiiE-mediated Salmonella adhesion.
For the EU “effective multilateralism” in, with and within international organisations is the foundation of a system of global governance, so is laid down in the ESS. Therefore the term is used to label the EU’s activities in the UN-family and to characterise the relations with the UN in the wider context of global governance. It is the political argument for the EU’s commitment in military crisis management, side by side with UN peacekeepers. The UN in turn speaks of multilateralism to call for the EU’s loyalty and partnership. Both organisations build their partnership on the common normative ground of multilateralism. The paper questions these rhetorical denominations critically. It goes beyond the political declarations to analyse the degree and quality of “effective multilateralism” in reality in and with international organisations, using the example of UN-EU-relations in military crisis management. The theoretical approach of multilateralism serves as the starting point of the analysis and theoretical basis of the paper (Chapter 1). The special EU-touch in “effective multilateralism” in comparison to the “UN-touch” is subject of Chapter 2. This analysis is necessary due to the meanwhile inflationary use of the term “effective multilateralism” in almost every CSFP context. Are the institutional steps to a partnership in crisis management as well as the operational collaboration in DR Congo (2003/2006/2009) and Chad/CAR (2008/2009) in line with “multilateralism”? is the question that is answered in the paper (Chapter 3).
Over the past decades, noncommutative geometry has grown into an established field in pure mathematics and theoretical physics. The discovery that noncommutative geometry emerges as a limit of quantum gravity and string theory has provided strong motivations to search for physics beyond the standard model of particle physics and also beyond Einstein's theory of general relativity within the realm of noncommutative geometries. A very fruitful approach in the latter direction is due to Julius Wess and his group, which combines deformation quantization (star-products) with quantum group methods. The resulting gravity theory does not only include noncommutative effects of spacetime, but it is also invariant under a deformed Hopf algebra of diffeomorphisms, generalizing the principle of general covariance to the noncommutative setting. The purpose of the first part of this thesis is to understand symmetry reduction in noncommutative gravity, which then allows us to find exact solutions of the noncommutative Einstein equations. These are important investigations in order to capture the physical content of such theories and to make contact to applications in e.g. noncommutative cosmology and black hole physics. We propose an extension of the usual symmetry reduction procedure, which is frequently applied to the construction of exact solutions of Einstein's field equations, to noncommutative gravity and show that this leads to preferred choices of noncommutative deformations of a given symmetric system. We classify in the case of abelian Drinfel'd twists all consistent deformations of spatially flat Friedmann-Robertson-Walker cosmologies and of the Schwarzschild black hole. The deformed symmetry structure allows us to obtain exact solutions of the noncommutative Einstein equations in many of our models, for which the noncommutative metric field coincides with the classical one. In the second part we focus on quantum field theory on noncommutative curved spacetimes. We develop a new formalism by combining methods from the algebraic approach to quantum field theory with noncommutative differential geometry. The result is an algebra of observables for scalar quantum field theories on a large class of noncommutative curved spacetimes. A precise relation to the algebra of observables of the corresponding undeformed quantum field theory is established. We focus on explicit examples of deformed wave operators and find that there can be noncommutative corrections even on the level of free field theories, which is not the case in the simplest example of the Moyal-Weyl deformed Minkowski spacetime. The convergent deformation of simple toy-models is investigated and it is shown that these quantum field theories have many new features compared to formal deformation quantization. In addition to the expected nonlocality, we obtain that the relation between the deformed and the undeformed quantum field theory is affected in a nontrivial way, leading to an improved behavior of the noncommutative quantum field theory at short distances, i.e. in the ultraviolet. In the third part we develop elements of a more powerful, albeit more abstract, mathematical approach to noncommutative gravity. The goal is to better understand global aspects of homomorphisms between and connections on noncommutative vector bundles, which are fundamental objects in the mathematical description of noncommutative gravity. We prove that all homomorphisms and connections of the deformed theory can be obtained by applying a quantization isomorphism to undeformed homomorphisms and connections. The extension of homomorphisms and connections to tensor products of modules is clarified, and as a consequence we are able to add tensor fields of arbitrary type to the noncommutative gravity theory of Wess et al. As a nontrivial application of the new mathematical formalism we extend our studies of exact noncommutative gravity solutions to more general deformations.
In this work, the trap states in the conjugated polymer P3HT, often used as electron donor in organic bulk heterojunction solar cells, three commonly used fullerene based electron acceptors and P3HT:PC61BM blends were investigated. Furthermore, the trap states in the blend were compared with these of the pure materials. Concerning the lifetime of organic solar cells the influence of oxygen on P3HT and P3HT:PC61BM blends was studied. The experimental techniques used to investigate the trap states in the organic semiconductors were (fractional) thermally stimulated current (TSC) and current based deep level transient spectroscopy (Q-DLTS). Fractional TSC measurements on P3HT diodes revealed a quasi-continuous trap distribution. The distribution suggested two different traps in P3HT with approximately Gaussian energy distributions and maxima at about 50 meV and 105 meV. Thereby, the former was attributed to the tail states within the regular Gaussian density of states due to the low activation energy. The latter, deeper traps, however, exhibited a strong dependence on oxygen. Exposure of the P3HT diodes to oxygen, ambient air and synthetic (dry) air all revealed an increase of the deeper traps density with exposure time in the same manner. While the lower limit of the trap density in non aged P3HT samples was in the range of (1.0 − 1.2)×10^22 m^−3, it was more than doubled after an exposure of 50 h to air. An increase of the trap density with oxygen exposure time was also seen in the Q-DLTS measurements accompanied with an increase of the temperature dependence of the emission rates, indicating an enhanced formation of deeper traps. Due to the raise in density of the deeper traps, the charge carrier mobility in P3HT significantly decreased, as revealed by photo-CELIV measurements, resulting in a loss in mobility of about two orders of magnitude after 100 h exposure to synthetic air. The increased trap density was attributed to p-doping of P3HT by the transfer of an electron to adsorbed oxygen. This effect was partially reversible by applying vacuum to the sample for several hours or, more significantly, by a thermal treatment of the devices in nitrogen atmosphere. The trap states in the methanofullerenes PC61BM, bisPC61BM and PC71BM were investigated by TSC measurements. PC61BM yielded a broad quasi-continuous trap distribution with the maximum of the distribution at about 75 meV. The comparison of the TSC spectra of the three methanofullerenes exhibited significant differences in the trap states with higher activation energies of the most prominent traps in bisPC61BM and PC71BM compared to PC61BM. This probably originates from the different isomers bisPC61BM and PC71BM consist of. Each of the isomers yields different LUMO energies, where the lower ones can act as traps. The lower limit of the trap density of all of the three investigated fullerene derivatives exhibited values in the order of 10^22 m^−3, with the highest for bisPC61BM and the lowest for PC61BM. By applying fractional TSC measurements on P3HT:PC61BM solar cells, it was shown that the trap distribution in the blend is a superposition of the traps in pure P3HT and PC61BM and additional deeper traps in the range of about 250 meV to 400 meV. The origin of these additional traps, which can not be related to the pure materials, was attributed to a higher disorder in the blend and P3HT/PC61BM interfaces. This conclusion was supported by standard TSC and Q-DLTS measurements performed on pristine and annealed P3HT:PC61BM blends, exhibiting a higher ratio of the deep traps in the pristine samples. The lower limit of the trap density of the investigated annealed solar cells was in the range of (6−8)×10^22 m^−3, which was considerably higher than in the pure materials. The influence of oxygen on P3HT:PC61BM solar cells was investigated by exposure of the devices to synthetic air under specific conditions. Exposure of the solar cells to oxygen in the dark resulted in a strong decrease in the power conversion efficiency of 60 % within 120 h, which was only caused by a loss in short-circuit current. Simultaneous illumination of the solar cells during oxygen exposure strongly accelerated the degradation, resulting in an efficiency loss of 30 % within only 3 h. Thereby, short-circuit current, open-circuit voltage and fill factor all decreased in the same manner. TSC measurements revealed an increase of the density of deeper traps for both degradation conditions, which resulted in a decrease of the mobility, as investigated by CELIV measurements. However, these effects were less pronounced than in pure P3HT. Furthermore, an increase of the equilibrium charge carrier density with degradation time was observed, which was attributed to oxygen doping of P3HT. With the aid of macroscopic simulations, it was shown that the doping of the solar cells is the origin of the loss in short-circuit current for both degradation conditions.
Background:
Pre- and early clinical studies on patients with autoimmune diseases suggested that induction of regulatory T(T(reg)) cells may contribute to the immunosuppressive effects of glucocorticoids(GCs).
Objective:
We readdressed the influence of GC therapy on T(reg) cells in immunocompetent human subjects and naive mice.
Methods:
Mice were treated with increasing doses of intravenous dexamethasone followed by oral taper, and T(reg) cells in spleen and blood were analyzed by FACS. Sixteen patients with sudden hearing loss but without an inflammatory disease received high-dose intravenous prednisolone followed by stepwise dose reduction to low oral prednisolone. Peripheral blood T(reg) cells were analyzed prior and after a 14 day GC therapy based on different markers.
Results:
Repeated GC administration to mice for three days dose-dependently decreased the absolute numbers of T(reg) cells in blood (100 mg dexamethasone/kg body weight: 2.8 +/- 1.8 x 10(4) cells/ml vs. 33 +/- 11 x 10(4) in control mice) and spleen (dexamethasone: 2.8 +/- 1.9 x 10(5)/spleen vs. 95 +/- 22 x 10(5)/spleen in control mice), which slowly recovered after 14 days taper in spleen but not in blood. The relative frequency of FOXP3(+) T(reg) cells amongst the CD4(+) T cells also decreased in a dose dependent manner with the effect being more pronounced in blood than in spleen. The suppressive capacity of T(reg) cells was unaltered by GC treatment in vitro. In immunocompetent humans, GCs induced mild T cell lymphocytosis. However, it did not change the relative frequency of circulating T(reg) cells in a relevant manner, although there was some variation depending on the definition of the T(reg) cells (FOXP3(+): 4.0 +/- 1.5% vs 3.4 +/- 1.5%*; AITR(+): 0.660.4 vs 0.5 +/- 0.3%, CD127(low): 4.0 +/- 1.3 vs 5.0 +/- 3.0%* and CTLA4+: 13.8 +/- 11.5 vs 15.6 +/- 12.5%; * p < 0.05).
Conclusion:
Short-term GC therapy does not induce the hitherto supposed increase in circulating T(reg) cell frequency, neither in immunocompetent humans nor in mice. Thus, it is questionable that the clinical efficacy of GCs is achieved by modulating T(reg) cell numbers.
Cell adhesion and migration are essential for development and homeostasis. Adhesion to the extracellular matrix occurs at specialized plasma membrane domains where transmembrane adhesion receptors, signaling proteins such as kinases and phosphatases, and a large number of adaptor proteins interact with the cytoskeleton in a tightly regulated and synchronized fashion. Whereas altered cell adhesion and migration are known to be important in cardiovascular disease and malignant tumors, the target proteins and molecular interactions that regulate these complex processes still remain incompletely understood. Whereas numerous kinases are known to regulate cell adhesion dynamics, information about the involved protein phosphatases is still very limited. A newly emerging phosphatase family contains the unconventional active site sequence DXDX(T/V) and belongs to the haloacid dehalogenase (HAD) superfamily of hydrolases. Our laboratory has recently discovered AUM, a novel phosphatase that belongs to this poorly characterized enzyme family. Initial findings pointed toward a potential involvement of AUM in the regulation of cell adhesion to the extracellular matrix. The objective of the present study was to study the potential role of AUM in cell adhesion. We could show that cells stably depleted of AUM are characterized by accelerated adhesion on immobilized fibronectin. To confirm these findings, we used an siRNA-based approach for the acute depletion of AUM and observed a similar phenomenon. Rescue experiments were performed with stably AUM-depleted cells to ensure that the above mentioned effects are indeed AUM specific. We observed that the re-addition of AUM normalizes cellular adhesion kinetics on fibronectin. These results clearly show that AUM exerts important functions in cell-matrix adhesion. To investigate the molecular basis of these effects, we have characterized integrin expression patterns using flow cytometry. Interestingly, fibronectin-stimulated AUM-depleted cells are characterized by an increase in the cell surface expression of conformationally active 1-integrins. Consistent with the important role of 1-integrins in the regulation of RhoA activity, we also observed a specific increase in RhoA-GTP, but not Rac1-GTP-levels during cell adhesion to fibronectin. Consistent with these findings and with the important role of RhoA for focal adhesion maturation, AUM depleted cells showed more elongated and more centripetally oriented focal adhesions as compared to control cells when spread on fibronectin. Taken together, this study has revealed an important role of AUM for cell-matrix adhesion. Our findings strongly suggest that AUM functions as a negative regulator of 1-integrins and RhoA-dependent cytoskeletal dynamics during cell adhesion.