Studien zur Totalsynthese der Elansolide mit der Substrat-kontrollierten, asymmetrischen Yamamoto-Aldolreaktion als Schlüsselschritt

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Das aktive Beschwerdemanagement mit einer Fokussierung der Beschwerdekanäle

Ziel der Diplomarbeit ist es, die Beschwerdekanäle zu analysieren, um festzustellen, welche Wege im aktiven Beschwerdemanagement am geeignetsten sind, um nachhaltiges Beschwerdemanagement zu betreiben. Hinsichtlich der Chancen, die sich durch ein wohlorganisiertes Beschwerdemanagement auftun, ist es angebracht,schon bei den Kanälen, über die sich Kunden äußern können, Verbesserungen anzustreben. Zunächst wird über die Grundlagen des Beschwerdemanagements informiert. Danach werden die einzelnen Beschwerdekanäle analysiert. Zum Schluss erfolgen eine Würdigung und das Fazit

Ionic currents and intrinsic properties of key interneurons and their influence on network activity in a chain of coupled oscillators

Post-inhibitory rebound (PIR) plays an important role in producing rhythmic network activity. By inducing new excitation, following a phase of inhibition it promotes the generation of rhythmic neuronal activity. I investigated this property in identified neurons of the swimmeret system. These neurons are characterized by membrane potential oscillations and create the well-coordinated Power- and Return-Stroke movements of four pairs of swimmerets at the abdomen of crayfish. I isolated the abdominal nervous system and performed current clamp recordings with sharp electrodes at the dendritic aborizations of the neurons. I tested whether the neurons are able to produce a PIR by injecting hyperpolarizing current pulses. All spiking neurons (PSE, RSE, ASCE and DSC) possessed the ability to produce a PIR, which was accompanied by a small sag potential. In contrast, not all neurons of the central pattern generator, IPS, generated a PIR. The only neuron receiving excitatory synaptic input, ComInt1, also produce a PIR. Different ionic currents are shown in various studies to account for the generation of a PIR. Those are the L-type calcium current (ICaL), the hyperpolarization activated cation current (IH), and in some systems the persistent sodium current (INaP). In the following experiments, I investigated the ionic basis of the PIR in the above described neuron groups. I could detect that both ICaL and IH and partially INaP generate PIR responses in the spiking neurons PSE, RSE, ASCE and DSC, while only IH seemed to be involved in generating the PIR in IPS. To test the significance of the identified ionic conductances for generation of rhythmic motor output, I blocked the respective ionic currents individually while monitoring fictive locomotion of the system on the network-, as well as on the single cell level. During this series of experiments also the contribution of the transient potassium current, IA, was investigated by application of 4-AP. Confirming the importance of the above identified currents (ICaL, IH and INaP), all ion channel blockers altered the ability of the entire system to produce a steady motor rhythm. Similar strong effects were observed when blocking IA. These results of this study demonstrate that PIR is an essential mechanism for the neurons in the swimmeret system to induce new excitability after a phase of inhibition. This suggests that PIR plays a crucial role in establishing rhythmic cellular activity. Furthermore, I could show that PIR responses were mediated by different ionic current depending on the neuron group

A unifying minimax theorem

In the present note, a minimax theorem is given which combines the most general topological and quantitative conditions employed in the literature. This result encompasses a large part of the classes of topological, quantitative, and mixed minimax theorems, and includes several new variants

Corporate social and environmental responsibility in India - assessing the UN global compact's role

"This report presents the results of a research project carried out as part of the postgraduate training course of the German Development Institute (GDI), Bonn, in close cooperation with the Centre for Social Markets, India, and with the support of Ashok V. Desai, Consultant Editor of the Telegraph, India. The report is based on studies of the literature and on empirical data collected in India’s main industrial districts of Delhi, Mumbai, Pune, Bangalore and Chennai from February to April 2006. The GDI research team would like to thank Sachin Joshi of the Centre for Social Markets and Ashok V. Desai for their strong scientific and technical support, without which this study would not have been possible. The research team would also like to express their thanks to the top officials of almost 40 Indian and foreign companies and 32 other stakeholders who spoke of their experience and responded to our questionnaire on CSR in India and the role of the UN Global Compact in particular. Last but not least, the authors are very grateful to experts from other Indian, international and German institutions who were kind enough to share their knowledge with us and so contributed to the writing of the report. However, the GDI team alone is responsible for the results presented here." (excerpt)Der vorliegende Beitrag untersucht die UN Global Compact-Initiative (UNGC), die im Jahr 2000 von dem damaligen UN-Generalsekretär Kofi Annan aus der Taufe gehoben wurde, unter besonderer Berücksichtigung der sozialen und ökologischen Aktivitäten in Indien. Der Global Compact, ein weltweiter Pakt, der zwischen Unternehmen und der UNO geschlossen wird, basiert auf zehn Prinzipien, die der Einhaltung bestimmter sozialer und ökologischer Mindeststandards dienen. Dies sind beispielsweise die wesentlichen Konventionen zur Einhaltung der Menschenrechte, Vereinigungsfreiheit, keine Zwangsarbeit, keine Kinderarbeit, Nicht-Diskriminierung, wesentliche Prinzipien, wie sie in den Rio-Konventionen zum Umweltschutz verfasst worden sind, sowie das Prinzip gegen alle Formen von Korruption. (ICD2

Association of Thigh Muscle Strength with Texture Features Based on Proton Density Fat Fraction Maps Derived from Chemical Shift Encoding-Based Water-Fat MRI

Purpose: Based on conventional and quantitative magnetic resonance imaging (MRI), texture analysis (TA) has shown encouraging results as a biomarker for tissue structure. Chemical shift encoding-based water–fat MRI (CSE-MRI)-derived proton density fat fraction (PDFF) of thigh muscles has been associated with musculoskeletal, metabolic, and neuromuscular disorders and was demonstrated to predict muscle strength. The purpose of this study was to investigate PDFF-based TA of thigh muscles as a predictor of thigh muscle strength in comparison to mean PDFF. Methods: 30 healthy subjects (age = 30 ± 6 years; 15 females) underwent CSE-MRI of the lumbar spine at 3T, using a six-echo 3D spoiled gradient echo sequence. Quadriceps (EXT) and ischiocrural (FLEX) muscles were segmented to extract mean PDFF and texture features. Muscle flexion and extension strength were measured with an isokinetic dynamometer. Results: Of the eleven extracted texture features, Variance(global) showed the highest significant correlation with extension strength (p 2adj = 0.712), and Correlation showed the highest significant correlation with flexion strength (p = 0.016, R2adj = 0.658). Multivariate linear regression models identified Variance(global) and sex, but not PDFF, as significant predictors of extension strength (R2adj = 0.709; p 2adj = 0.674; p < 0.001). Conclusions: Prediction of quadriceps muscle strength can be improved beyond mean PDFF by means of TA, indicating the capability to quantify muscular fat infiltration patterns

Choroid plexus volume in multiple sclerosis vs neuromyelitis optica spectrum disorder: a retrospective, cross-sectional analysis

BACKGROUND AND OBJECTIVES: The choroid plexus has been shown to play a crucial role in CNS inflammation. Previous studies found larger choroid plexus in multiple sclerosis (MS) compared with healthy controls. However, it is not clear whether the choroid plexus is similarly involved in MS and in neuromyelitis optica spectrum disorder (NMOSD). Thus, the aim of this study was to compare the choroid plexus volume in MS and NMOSD. METHODS: In this retrospective, cross-sectional study, patients were included by convenience sampling from 4 international MS centers. The choroid plexus of the lateral ventricles was segmented fully automatically on T1-weighted MRI sequences using a deep learning algorithm (Multi-Dimensional Gated Recurrent Units). Uni- and multivariable linear models were applied to investigate associations between the choroid plexus volume, clinically meaningful disease characteristics, and MRI parameters. RESULTS: We studied 180 patients with MS and 98 patients with NMOSD. In total, 94 healthy individuals and 47 patients with migraine served as controls. The choroid plexus volume was larger in MS (median 1,690 µL, interquartile range [IQR] 648 µL) than in NMOSD (median 1,403 µL, IQR 510 µL), healthy individuals (median 1,533 µL, IQR 570 µL), and patients with migraine (median 1,404 µL, IQR 524 µL; all p < 0.001), whereas there was no difference between NMOSD, migraine, and healthy controls. This was also true when adjusted for age, sex, and the intracranial volume. In contrast to NMOSD, the choroid plexus volume in MS was associated with the number of T2-weighted lesions in a linear model adjusted for age, sex, total intracranial volume, disease duration, relapses in the year before MRI, disease course, Expanded Disability Status Scale score, disease-modifying treatment, and treatment duration (beta 4.4; 95% CI 0.78-8.1; p = 0.018). DISCUSSION: This study supports an involvement of the choroid plexus in MS in contrast to NMOSD and provides clues to better understand the respective pathogenesis