University of Gttingen

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Germany
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Al-Ramamneh D.,University of Gttingen | Riek A.,University of Gttingen | Riek A.,University of New England of Australia | Gerken M.,University of Gttingen
Animal | Year: 2010

The aim of this study was to test whether the deuterium oxide dilution technique accurately predicts water intake in sheep and goats. Two other issues were also studied: (i) a comparison of water intake in sheep and goats and (ii) an assessment of whether observations of drinking behaviour can accurately measure the water intake. In this study, eight dry Boer goats and eight dry German Black Head Mutton ewes were kept under controlled stable conditions. Animals had access to hay and water ad libitum. Diurnal drinking behaviour was recorded by video. Individual daily water intake was measured and estimated for 2 weeks by re-weighing water buckets and from water kinetics using the deuterium oxide dilution technique, respectively. In addition, dry matter intakes were directly measured and were significantly higher in sheep than in goats. The average daily water consumption by drinking differed significantly between the two species, with higher intakes in sheep than in goats. Total body water expressed as a percentage of body mass did not differ between species. Measurement methods of total water intake (TWI) using deuterium oxide dilution and re-weighing water buckets did not differ significantly in both species (P = 0.926). Results obtained for measured and estimated TWI confirm that the isotope dilution technique gives reliable results for estimates of water intake in sheep and goats. The higher amount of water intake in sheep was also reflected by their drinking behaviour. Sheep spent approximately 0.3% per 24-h drinking, while Boer goats spent only 0.1%. However, measured and estimated TWIs were only moderately correlated to the daily time spent drinking. The lower water intake found in Boer goats confirms a superior water management capacity compared with Black Head Mutton sheep even under temperate conditions. Copyright © The Animal Consortium 2010.


Morawe C.,European Synchrotron Radiation Facility | Osterhoff M.,European Synchrotron Radiation Facility | Osterhoff M.,University of Gttingen
X-Ray Optics and Instrumentation | Year: 2010

This paper provides a comprehensive overview on the utilization of curved graded multilayer coatings as focusing elements for hard X-rays. It concentrates on the Kirkpatrick-Baez (KB) focusing setup that has been developed at 3rd generation synchrotron sources worldwide. The optical performance of these devices is evaluated applying analytical and numerical approaches. The essential role of the multilayer coating and its meridional d-spacing gradient are discussed as well as important technological issues. Experimental data and examples of operational KB focusing devices and applications complement the work. © 2010 Christian Morawe and Markus Osterhoff.


Fledrich R.,Max Planck Institute for Experimental Medicine | Stassart R.M.,Max Planck Institute for Experimental Medicine | Stassart R.M.,University of Gttingen | Sereda M.W.,Max Planck Institute for Experimental Medicine | Sereda M.W.,University of Gttingen
British Medical Bulletin | Year: 2012

Introduction or Background:L Charcot-Marie-Tooth (CMT) disease represents a broad group of inherited motor and sensory neuropathies which can originate from various genetic aberrations, e.g. mutations, deletions and duplications.Sources of data: We performed a literature review on murine animal models of CMT disease with regard to experimental therapeutic approaches. Hereby, we focussed on the demyelinating subforms of CMT (CMT1). PubMed items were CMT, animal model, demyelination and therapy.Areas of agreement: Patients affected by CMT suffer from slowly progressive, distally pronounced muscle atrophy caused by an axonal loss. The disease severity is highly variable and impairments may result in wheelchair boundness. No therapy is available yet.Areas of controversy: Numerous rodent models for the various CMT subtypes are available today. The selection of the correct animal model for the specific CMT subtype provides an important prerequisite for the successful translation of experimental findings in patients.Growing points: Despite more than 20 years of remarkable progress in CMT research, the disease is still left untreatable. There is a growing number of experimental therapeutic strategies that may be translated into future clinical trials in patients with CMT.Areas timely for developing research: The slow disease progression and insensitive outcome measures hamper clinical therapy trials in CMT. Biomarkers may provide powerful tools to monitor therapeutic efficacy. Recently, we have shown that transcriptional profiling can be utilized to assess and predict the disease severity in a transgenic rat model and in affected humans. © 2012 The Author.


Ehrenthal J.C.,University of Heidelberg | Herrmann-Lingen C.,University of Gttingen | Fey M.,University of Gttingen | Schauenburg H.,University of Heidelberg
World Journal of Biological Psychiatry | Year: 2010

Objectives. Despite its clinical importance and relevance for health care policy, the pathways between depression and stress regulation remain poorly understood. The objective of our study was to compare cardiovascular and autonomic responses to brief psychosocial stress in a group of severely depressed subjects without heart disease and a non-depressed control-group. Methods. We recorded cardiovascular and autonomic reactions to two different stress tasks including anger recall and mental arithmetic in a sample of 25 severely depressed and 25 non-depressed subjects. Aggregated data were compared with repeated-measures MANOVA. We used contrasts to evaluate different response patterns concerning cardiovascular and autonomic reactivity vs. recovery. Results. Depressed subjects showed overall reduced high-frequency heart rate variability and an altered cardiovascular adaptability concerning heart rate, blood pressure, cardiac output, and, on a trend level, peripheral resistance. With few exceptions, we found no differences between reactivity vs. recovery response patterns. Conclusions. Our results provide further evidence for altered cardiovascular reactivity and impaired cardiac autonomic functioning in depression. Further research is needed on psychophysiological response to either more disease-oriented or more personality-oriented stressors. © 2010 Informa UK Ltd.


Troe J.,University of Gttingen | Troe J.,Max Planck Institute for Biophysical Chemistry | Ushakov V.G.,RAS Institute of Problems of Chemical Physics
Journal of Chemical Physics | Year: 2011

Master equations for thermal unimolecular reactions and the reverse thermal recombination reactions are solved for a series of model reaction systems and evaluated with respect to broadening factors. It is shown that weak collision center broadening factors Fc en twc can approximately be related to the collision efficiencies c through a relation Fc en twc ≈ max { c 0.14, 0.64(0.03)}. In addition, it is investigated to what extent weak collision falloff curves in general can be expressed by the limiting low and high pressure rate coefficients together with central broadening factors F cent only. It is shown that there cannot be one best analytical expression for broadening factors F(x) as a function of the reduced pressure scale x k 0k ∞. Instead, modelled falloff curves of various reaction systems, for given k 0, k ∞, and F cent, fall into a band of about 10 width in F(x). A series of analytical expressions for F(x), from simple symmetric to more elaborate asymmetric broadening factors, are compared and shown to reproduce the band of modelled broadening factors with satisfactory accuracy. © 2011 American Institute of Physics.


Quezada-Pina A.,CICESE | Tchernykh A.,CICESE | Gonzlez-Garca J.L.,University of Gttingen | Hirales-Carbajal A.,CICESE | And 5 more authors.
Future Generation Computer Systems | Year: 2012

We evaluate job scheduling algorithms that integrate both tasks of Grid scheduling: job allocation to Grid sites and local scheduling at the sites. We propose and analyze an adaptive job allocation scheme named admissible allocation. The main idea of this scheme is to set job allocation constraints, and dynamically adapt them to cope with different workloads and Grid properties. We present 3-approximation and 5-competitive algorithms named MLB a+PS and MCT a+PS for the case that all jobs fit to the smallest machine, while we derive an approximation factor of 9 and a competitive factor of 11 for the general case. To show practical applicability of our methods, we perform a comprehensive study of the practical performance of the proposed strategies and their derivatives using simulation. To this end, we use real workload traces and corresponding Grid configurations. We analyze nine scheduling strategies that require a different amount of information on three Grid scenarios. We demonstrate that our strategies perform well across ten metrics that reflect both user- and system-specific goals. © 2011 Elsevier B.V. All rights reserved.


Botschwina P.,University of Gttingen | Oswald R.,University of Gttingen
Journal of Chemical Physics | Year: 2011

Explicitly correlated coupled cluster theory at the CCSD(T)-F12x (x a, b) level T. B. Adler, J. Chem. Phys. 127, 221106 (2007) has been employed in a study of the potential energy surfaces for the complexes H2C 3H+ · Ar and c-C3H3 + · Ar. For the former complex, a pronounced minimum with Cs symmetry was found (De ≈ 780 cm-1), well below the local "H-bound" minimum with C2v symmetry (D e ≈ 585 cm-1). The absorption at 3238 cm-1 found in the recent infrared photodissociation spectra A. M. Ricks, J. Chem. Phys. 132, 051101 (2010) is, thus, interpreted as an essentially free acetylenic CH stretching vibration of the propargyl cation. A global minimum of C s symmetry was also obtained for c-C3H3 + (De ≈ 580 cm-1), but the energy difference with respect to the local C2v minimum is only 54 cm-1. © 2011 American Institute of Physics.


Klemm F.,University of Gttingen | Bleckmann A.,University of Gttingen | Siam L.,University of Gttingen | Chuang H.N.,University of Gttingen | And 11 more authors.
Carcinogenesis | Year: 2011

A role of WNT signaling for primary breast cancers of the basal-like subtype and as a predictor of brain metastasis has been described. However, a responsible WNT ligand has not been identified. To further clarify this question, we comparatively investigated 22 human breast cancer brain metastases as well as the highly invasive human breast cancer cell line MDA-MB-231 and the weakly motile MCF-7 as models for the basal-like and the luminal A subtype. WNT5A and B were found overexpressed in MDA-MB-231 cells as compared with MCF-7. This corresponded to reduction of MDA-MB-231 invasiveness by WNT inhibitors, whereas MCF-7 invasion was enhanced by recombinant WNT5B and abolished by WNT and Jun-N-terminal kinase antagonists. Expression and subcellular distribution of β-catenin remained uninfluenced. Consistently, β-catenin was not localized in the nuclei of brain metastases while there was strong nuclear c-Jun staining. Similar to MDA-MB-231, metastases showed expression of WNT5A/B and the alternative WNT receptors ROR1 and 2. These findings were validated using external gene expression datasets (Gene Expression Omnibus) of different breast cancer subtypes and brain metastases. Hierarchical cluster analysis yielded a close relation between basal-like cancers and brain metastases. Gene set enrichment analyses confirmed WNT pathway enrichment not only in basal-like primaries but also in cerebral metastases of all subtypes. In conclusion, WNT signaling seems highly relevant for basal-like and other subtypes of breast cancers metastasizing into the brain. β-catenin-independent WNT signaling, presumably via ROR1-2, plays a major role in this context. © The Author 2010. Published by Oxford University Press. All rights reserved.


Ebert S.,University of Gttingen | Nau R.,University of Gttingen | Michel U.,University of Gttingen
Immunotherapy | Year: 2010

Severe bacterial infections such as sepsis and meningitis still kill or severely injure people despite the use of bactericidal antibiotics. Therefore, new strategies for a better therapy are needed. Activin A, a member of the TGF- superfamily and its binding protein follistatin (FS) are released by various cell types during acute and chronic inflammatory processes. Until now, a clear definition of conditions in which activin A exerts either its pro- or anti-inflammatory functions is lacking. The activin/FS-system participates in the fine-tuning of the hosts inflammatory response upon infectious stimuli. This response is on the one hand necessary for fighting pathogens, but on the other hand can negatively affect the host. This article focuses on the role of activin A and FS in infection and after acute inflammatory stimuli. The therapeutic potentials of blocking or promoting activin actions are discussed. © 2010 Future Medicine Ltd.


Misassignment between DNA samples and clinical or epidemiological data may compromise the results of genetic association studies. Genotyping in replicates or controlling for Hardy-Weinberg equilibrium cannot identify misassignments caused by sample mix-ups. DNA-based sex identification (sex typing) is currently the best strategy to identify mix-ups. Here we review the available methods and present validated protocols for sex typing. The protocols are based on single-nucleotide differences between the human amelogenin genes, AMELX and AMELY, and are optimized for real-time PCR (TaqMan®), primer-extension (SNaPshot™) and PCR-RFLP genotyping platforms. In addition, we review the limitations of the sex-typing strategy, including a limited ability to identify single sample mix-ups, the dependence of the power of this approach on the sex distribution in the study population, and rare genetic conditions. Alternative strategies for mix-up identification and possible consequences of mix-up identification are also discussed. © 2010 Future Medicine Ltd.

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