759 research outputs found
Focal adhesion kinase regulates the activity of the osmosensitive transcription factor TonEBP/NFAT5 under hypertonic conditions
Ton EBP/NFAT5 is a major regulator of the urinary concentrating process and is essential for the osmoadaptation of renal medullary cells. Focal adhesion kinase (FAK) is a mechanosensitive non-receptor protein tyrosine kinase expressed abundantly in the renal medulla. Since osmotic stress causes cell shrinkage, the present study investigated the contribution of FAK on TonEBP/NFAT5 activation. Osmotic stress induced time-dependent activation of FAK as evidenced by phosphorylation at Tyr-397, and furosemide reduces FAK Tyr-397 phosphorylation in the rat renal medulla. Both pharmacological inhibition of FAK and siRNA-mediated knockdown of FAK drastically reduced TonEBP/NFAT5 transcriptional activity and target gene expression in HEK293 cells. This effect was not mediated by impaired nuclear translocation or by reduced transactivating activity of TonEBP/NFAT5. However, TonEBP/NFAT5 abundance under hypertonic conditions was diminished by 50% by FAK inhibition or siRNA knockdown of FAK. FAK inhibition only marginally reduced transcription of the TonEBP/NFAT5 gene. Rather, TonEBP/NFAT5 mRNA stability was diminished significantly by FAK inhibition, which correlated with reduced reporter activity of the TonEBP/NFAT5 mRNA 3' untranslated region (3'-UTR). In conclusion, FAK is a major regulator of TonEBP/NFAT5 activity by increasing its abundance via stabilization of the mRNA. This in turn, depends on the presence of the TonEBP/NFAT5 3'-UTR
QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
A QCD analysis of the world data on polarized deep inelastic scattering is
presented in leading and next-to-leading order. New parameterizations are
derived for the quark and gluon distributions for the kinematic range x
\epsilon [10^{-9},1], Q^2 \epsilon [1,10^6] \GeV^2. The extrapolation far
outside the domain of the current measurements is given both to allow for
applications at higher values of and to be able to calculate integral
properties of the present distributions. The values of and
are determined. Emphasis is put on the derivation of the fully
correlated error bands for these distributions, which are also given
in terms of parameterizations and are directly applicable to determine
experimental errors of other polarized observables. The impact of the variation
of both the renormalization and factorization scales on the value of
is studied. Finally we perform a factorization--scheme invariant QCD analysis
based on the observables and in
next-to-leading order, which is compared to the standard analysis. A series of
low moments of parton densities, accounting for error correlation, are given to
allow for comparison with results from lattice simulations.Comment: 43 pages LATEX, 1 style files, 13 eps-figures, final version, Nucl.
Phys. B in prin
Financial Evaluation of Different Vaccination Strategies for Controlling the Bluetongue Virus Serotype 8 Epidemic in the Netherlands in 2008
Background: Bluetongue (BT) is a vector-borne disease of ruminants caused by bluetongue virus that is transmitted by biting midges (Culicoides spp.). In 2006, the introduction of BTV serotype 8 (BTV-8) caused a severe epidemic in Western and Central Europe. The principal effective veterinary measure in response to BT was believed to be vaccination accompanied by other measures such as movement restrictions and surveillance. As the number of vaccine doses available at the start of the vaccination campaign was rather uncertain, the Dutch Ministry of Agriculture, Nature and Food Quality and the Dutch agricultural industry wanted to evaluate several different vaccination strategies. This study aimed to rank eight vaccination strategies based on their efficiency (i.e. net costs in relation to prevented losses or benefits) for controlling the bluetongue virus serotype 8 epidemic in 2008 Methodology/Principal Findings: An economic model was developed that included the Dutch professional cattle, sheep and goat sectors together with the hobby farms. Strategies were evaluated based on the least cost - highest benefit frontier, the benefit-cost ratio and the total net returns. Strategy F, where all adult sheep at professional farms in the Netherlands would be vaccinated was very efficient at lowest costs, whereas strategy D, where additional to all adult sheep at professional farms also all adult cattle in the four Northern provinces would be vaccinated, was also very efficient but at a little higher costs. Strategy C, where all adult sheep and cattle at professional farms in the whole of the Netherlands would be vaccinated was also efficient but again at higher costs. Conclusions/Significance: This study demonstrates that a financial analysis differentiates between vaccination strategies and indicates important decision rules based on efficienc
The missing link: Bordetella petrii is endowed with both the metabolic versatility of environmental bacteria and virulence traits of pathogenic Bordetellae
Gross R, Guzman CA, Sebaihia M, et al. The missing link: Bordetella petrii is endowed with both the metabolic versatility of environmental bacteria and virulence traits of pathogenic Bordetellae. BMC Genomics. 2008;9(1): 449.Background: Bordetella petrii is the only environmental species hitherto found among the otherwise host-restricted and pathogenic members of the genus Bordetella. Phylogenetically, it connects the pathogenic Bordetellae and environmental bacteria of the genera Achromobacter and Alcaligenes, which are opportunistic pathogens. B. petrii strains have been isolated from very different environmental niches, including river sediment, polluted soil, marine sponges and a grass root. Recently, clinical isolates associated with bone degenerative disease or cystic fibrosis have also been described. Results: In this manuscript we present the results of the analysis of the completely annotated genome sequence of the B. petrii strain DSMZ12804. B. petrii has a mosaic genome of 5,287,950 bp harboring numerous mobile genetic elements, including seven large genomic islands. Four of them are highly related to the clc element of Pseudomonas knackmussii B13, which encodes genes involved in the degradation of aromatics. Though being an environmental isolate, the sequenced B. petrii strain also encodes proteins related to virulence factors of the pathogenic Bordetellae, including the filamentous hemagglutinin, which is a major colonization factor of B. pertussis, and the master virulence regulator BvgAS. However, it lacks all known toxins of the pathogenic Bordetellae. Conclusion: The genomic analysis suggests that B. petrii represents an evolutionary link between free-living environmental bacteria and the host-restricted obligate pathogenic Bordetellae. Its remarkable metabolic versatility may enable B. petrii to thrive in very different ecological niches
Deutsche Beiträge zum 14. Internationalen Slavistenkongress Ohrid 2008
Der vorliegende Band versammelt – mit wenigen Ausnahmen – die deutschen Beiträge zum 14. Internationalen Slavistenkongress in Ohrid, der vom 10.–16. September 2008 stattfand.
Der Band enthält insgesamt 40 Beiträge, von denen 32 der Rubrik Sprachwissenschaft und 8 der Rubrik Literaturwissenschaft zugeordnet wurden
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
Empirische Analyse des Studienabbruchs von Vollzeit- und Teilzeitstudenten nach dem 1. Studienjahr an der FernUniversität
Nach dem ersten halben Jahr des Fernstudiums wurden die Studienabbrecher befragt durch telefonische Interviews und einen Fragebogen. Insbesondere die Abbruchgründe zeitliche Belastung,, Isolierung und falsche Selbsteinschätzung wurden hervorgehoben. Die Abbruchquoten lagen zwischen 20% in Wirtschaftswissenschaften und 47% in Mathematik, und für Frauen durchschnittlich höher als für Männer. „Nonstarter“ sind solche Studierende, die zwar immatrikuliert waren, aber keinerlei Leistungsnachweise (Einsendearbeiten oder Klausurteilnahme) aufweisen - ein Anteil von bis zu 50% im ersten Halbjahr. Angefügt sind auch 30 Interview-Dokumentationen mit ehemaligen Fernstudierenden und der Fragebogen
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