检索结果-南通市图书馆

Role of HSP-90 for increased nNOS-mediated vasodilation in mesenteric arteries in portal hypertension

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2010年第15期16卷 1837-1844页

作者： Lukas Moleda Lars Jurzik Matthias Froh erwin gbele Claus Hellerbrand Rainer H Straub Jürgen Schlmerich Reiner Wiest Department of Internal Medicine I University Medical Center

AIM:To explore the role of heat shock protein-90 (HSP-90) for nitrergic vasorelaxation in the splanchnic circulation in rats with and without portal hypertension. METHODS: Neuronal nitric oxide synthase (nNOS) and HSP-90 were analyzed by immunofluorescence, western blotting and co-immunoprecipitation in the mesenteric vasculature and isolated nerves of portal-vein-ligated (PVL) rats and sham operated rats. In vitro perfused de-endothelialized mesenteric arterial vasculature was preconstricted with norepinephrine (EC80) and tested for nNOS-mediated vasorelaxation by periarterial nerve stimulation (PNS, 2-12 Hz, 45V) before and after incubation with geldanamycin (specific inhibitor of HSP-90 signalling, 3 μg/mL) or L-NAME (non-specific NOSblocker, 10-4 mol/L). RESULTS: nNOS and HSP-90 expression was significantly increased in mesenteric nerves from PVL as compared to sham rats. Moreover, nNOS and HSP-90 were visualized in mesenteric nerves by immunofluorescence and immunoprecipitation of nNOS co-immunoprecitated HSP-90 in sham and PVL rats. PNS induced a frequencydependent vasorelaxation which was more pronounced in PVL as compared to sham rats. L-NAME and geldanamycin markedly reduced nNOS-mediated vasorelaxation abrogating differences between the study groups. The effect of L-NAME and geldanamycin on nNOS-mediated vasorelaxation was significantly greater in PVL than in sham animals. However, no difference in magnitude of effect between L-NAME and geldanamycin was noted. CONCLUSION: HSP-90 acts as a signalling mediator of nNOS-dependent nerve mediated vascular responses in mesenteric arteries, and the increased nitrergic vasorelaxation observed in portal hypertension is mediated largely by HSP-90.

关键词： Heat shock protein-90 Nitric oxide Vasodilation Portal hypertension Mesenteric circulation

Adiponectin and its receptors in rodent models of fatty liver disease and liver cirrhosis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2006年第34期12卷 5490-5494页

作者： Markus Neumeier Claus Hellerbrand erwin gbele Roland Buettner Cornelius Bollheimer Johanna Weigert Andreas Schffler Thomas S Weiss Monika Lichtenauer Jürgen Schlmerich Christa Buechler Department of Internal Medicine I University of Regensburg D-93042 Regensburg Germany Department of Surgery Center for Liver Cell Research University of Regensburg Germany

AIM： To determine circulating and hepatic adiponectin in rodents with fatty liver disease or liver cirrhosis and investigate expression of the adiponectin receptors AdipoR1 on the mRNA and protein level and AdipoR2 on the mRNA level. METHODS： Fat fed rats were used as a model for fatty liver disease and bile duct ligation in mice to investigate cirrhotic liver. Expression of AdipoR1 and AdipoR2 mRNA was determined by real time RT-PCR. AdipoR1 protein was analysed by immunoblot. Adiponectin was measured by ELISA. RESULTS： Systemic adiponectin is reduced in fatfed rats but is elevated in mice after bile duct ligation （BDL）. Hepatic adiponectin protein is lower in steatotic liver but not in the liver of BE）L-mice when compared to controls. Adiponectin mRNA was not detected in human liver samples or primary human hepatocytes nor in rat liver but recombinant adiponectin is taken up by isolated hepatocytes in-vitro. AdipoR1 mRNA and AdipoR1 protein levels are similar in the liver tissue of control and fat fed animals whereas AdipoR2 mRNA is induced. AdipoR2 mRNA and AdipoR1 mRNA and protein is suppressed in the liver of BDL-mice. CONCLUSION： Our studies show reduced circulating adiponectin in a rat model of fatty liver disease whereas circulating adiponectin is elevated in a mouse model of cirrhosis and similar findings have been described in humans. Diminished hepatic expression of adiponectin receptors was only found in liver cirrhosis.

关键词： Hepatic steatosis Adiponectin Liver cirrhosis Adiponectin receptor 1 Adiponectin receptor 2

Portal hypertension and gastrointestinal bleeding:Diagnosis,prevention and management

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2013年第31期19卷 5035-5050页

作者： erwin Biecker Department of gastroenterology and Hepatology HELIOS Klinikum Siegburg 53129 Siegburg Germany

Bleeding from esophageal varices is a life threatening complication of portal *** prevention of bleeding in patients at risk for a first bleeding episode is therefore a major *** prophylaxis consists of non-selective beta-blockers like propranolol or *** endoscopic band ligation is equally effective but procedure related morbidity is a drawback of the *** of acute bleeding is based on three strategies:vasopressor drugs like terlipressin,antibiotics and endoscopic *** refractory bleeding,self-expandable stents offer an option for bridging to definite treatments like transjugular intrahepatic portosystemic shunt(TIPS).Treatment of bleeding from gastric varices depends on vasopressor drugs and on injection of varices with *** for primary or secondary prevention are based on non-selective beta-blockers but data from large clinical trials is *** of refractory bleeding relies on shuntprocedures like *** from ectopic varices,portal hypertensive gastropathy and gastric antral vascular ectasia-syndrome is less *** medical and endoscopic treatment options are discussed.

关键词： Portal hypertension Esophageal varices gastric varices Portal hypertensive gastropathy gastric antral vascular ectasia-syndrome Variceal bleeding Endoscopy Band ligation Beta-blocker

Inorganic Crystal Structure Data to be Presented in a Form More Useful for Further Studies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2004年第10期23卷 1150-1160页

作者：胡盛志 erwin PARTHé Department of Chemistry Xiamen University Xiamen 361005 China Institute for Mineralogy and Crystallography University of Vienna Vienna Austria and Department of Inorganic Chemistry University of Geneva Geneva Switzerland

To make inorganic structure data more useful for further studies a five-point list of simple procedures to be followed by authors of crystal structure papers is proposed. 1. A crystal structure should be described with the space group corresponding to its true symmetry. 2. A new structure proposal should be tested, if it is realistic in principle. 3. A structure should be described with a space group in a setting given in the International Tables. 4. For a comparison with other structures the structure data should be standardized with the program STRUCTURE TIDY. 5. 揘ew?structure data should be checked in the databases, Chemical Abstracts or on-line internet resources, if they are really new. The list is supplemented with many explanations, commentaries, examples and references.

关键词： inorganic crystal structures standardization of structure data comparative crystal structure studies

Influence of Flow Regime on the Vegetation Zonation along Mountain Streams in the Western Cape, South Africa

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2015年第6期12卷 1484-1498页

作者： erwin Jacobus Joannes SIEBEN University of the Free State Qwaqwa Campus Afromontane Research Unit

Zonation patterns of riparian vegetation have been sampled and described in mountain streams in two catchments in the Hottentots-Holland Mountains, Western Cape, South Africa. Six main vegetation types that differ in structure and species composition, are dominant along these river banks: Aquatic vegetation, Wetbanks, Palmiet, Scrub, Forest and Shrubland(Fynbos). The study aims to correlate the vegetation patterns to flooding patterns, in particular the inundation frequency and stream power. A problem arises: because these catchments are ungauged, like most mountain catchments, with the only weirs at the downstream end of the catchment. Discharge data at the weirs are extrapolated to the sites upstream by multiplication with a factor based on the size of the subcatchment that drains through a sample site. In this way, recurrence intervals for floods in mountain streams are derived. Discharges at sites are also calculated using bed roughness(Manning's n) and slope in straight sections with uniform flow conditions. Stream power is derived from the discharges calculated in this manner. The combination of stream power and recurrence intervals explains the occurrence of most vegetation types occurring on the banks, except for one type: Afromontane Forest. This type is probably more dependent on other factors, such as protection from fire and the depth of the groundwater table.

关键词： Hydrology Hydraulics Riparian vegetation Mountain streams Floods Stream power Manning's n.

Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第3期47卷 280-288页

作者： erwin Suess Dirk Rickert Department of Marine Environmental geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany Department of Marine Environmental Geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany

Characteristic gypsum micro-sphere and granular mass were discovered by bin-ocular microscope in the gas hydrate-associated sediments at cores SO143-221 and SO143/TVg40-2A respectively on Hydrate Ridge of Cascadia margin, the eastern North Pacific. XRD patterns and EPA analyses show both micro-sphere and granular mass of the crystals have the typical peaks and the typical main chemical compositions of gypsum, although their weight percents are slightly less than the others in the non-gas hydrate-associated marine regions. SEM pictures show that the gypsum crystals have clear crystal boundaries, planes, edges and cleav-ages of gypsum in form either of single crystal or of twin crystals. In view of the fact that there are meanwhile gas hydrate-associated authigenic carbonates and SO42--rich pore water in the same sediment cores, it could be inferred reasonably that the gypsums formed also authigenically in the gas hydrate-associated environment too, most probably at the interface between the down-ward advecting sulfate-rich seawater and the below gas hydrate, which spilled calcium during its formation on Hydrate Ridge. The two distinct forms of crystal intergrowth, which are the granular mass of series single gypsum crystals at core SO143/TVg40-2A and the microsphere of gypsum crystals accompanied with detrital components at core SO143-221 respectively, indicate that they precipitated most likely in different interstitial water dynamic environments. So, the distinct authigenic gypsums found in gas hydrate-associated sediments on Hydrate Ridge could also be believed as one of the parameters which could be used to indicate the presence of gas hydrate in an unknown marine sediment cores.

关键词： authigenic gypsum, gas hydrate-associated sediment, Hydrate Ridge, eastern North Pacific.

Late Holocene Moisture Changes in the Core Area of Arid Central Asia Reflected by Rock Magnetic Records of glacier Lake Kalakuli Sediments in the Westernmost Tibetan Plateau and their Influences on the Evolution of Ancient Silk Road

在线全文

学校读者我要写书评

暂无评论

Acta geologica Sinica(English Edition) 2020年第3期94卷 658-667页

作者： WU Xudong LIU Xingqi erwin APPEL College of Environmental Resources and Tourism Capital Normal UniversityBeijing 100048China School of Land Resources and Urban&Rural Planning Hebei Geo UniversityShijiazhuang 050031China Department of geosciences University of TübingenTübingen 72076Germany

The evolution of Ancient Silk Road(ASR) was deeply influenced by late Holocene moisture changes in Arid Central Asia(ACA). Nevertheless, controversies in Holocene moisture change pattern of ACA and poorly–constrained age models of related studies have made the discussion about late Holocene moisture changes in ACA and their influences on the evolution of ASR difficult. Recently, a high–resolution age model during the late Holocene was established for Kalakuli Lake, a small glacier lake located in the core area of ACA. A thorough rock magnetic investigation was carried out on Kalakuli Lake sediments based on this age model. The magnetic mineral assemblage of Kalakuli Lake sediments is still dominated by primary magnetite despite minor diagenetic effects. Comparisons of rock magnetic records to parameters previously used as indicator of glacier fluctuations suggest that clastic input to Kalakuli Lake was high(low) and magnetic grain size is relatively larger(smaller), when glaciers on Muztagh Ata advanced(retreated). The ARM/SIRM ratio, a magnetic grain size proxy, is directly related to lake hydrodynamics, which are ultimately controlled by glacier fluctuations on Muztagh Ata as the result of regional moisture changes. Late Holocene moisture changes indicated by the ARM/SIRM ratio are consistent with cool/wet and warm/dry oscillations indicated by the unweighted average of biomarker hydrogen isotopic data of the C26 and C28 n–alkanoic acids in a previous study about Kalakuli Lake, most moisture change records of the core area of ACA and winter insolation of the Northern Hemisphere, but opposite to Asian monsoon evolution. given Asian monsoon and the westerlies are mutually inhibited, we propose that late Holocene moisture changes in the core area of ACA were controlled by the intensity of Asian monsoon versus the westerlies under the governance of solar insolation. generally increased moisture since the late Holocene indicated by the ARM/SIRM ratio favored cultural e

关键词： moisture changes rock magnetic records Kalakuli Lake Arid Central Asia Ancient Silk Road

Near-neutral pH corrosion of mill-scaled X-65 pipeline steel with paint primer

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第14期47卷 166-178页

作者： Shidong Wang Lyndon Lamborn Karina Chevil erwin gamboa Weixing Chen Department of Chemical and Materials Engineering University of AlbertaEdmontonT6G 2G6Canada Enbridge Pipelines Inc. EdmontonT5J 3N7Canada TC Energy Corporation CalgaryT2P 5H1Canada

The corrosion behaviour of mill-scaled X65 pipeline steel with and without a primer layer was studied in a simulated near-neutral pH soil *** revealed a three-stage corrosion process of the mill-scaled pipeline steel *** first stage included an initial preferential dissolution of goethite(γ-FeOOH)and lepidocrocite(?-FeOOH)in mill *** second stage was marked by enhanced localized corrosion and pit-formation because of either galvanic corrosion or acidic dissolution in areas enclosed by mill *** final stage was general corrosion after the mill scale flaked off the steel *** the primer layer was applied,localized corrosion was significantly enhanced on the steel surface and persisted for an extended period as compared to the mill-scaled *** precipitation of siderite(FeCO3)was observed at flawed locations of mill scale,although the bulk chemistry is not favorable for its formation on the steel surface free of mill *** local precipitation of siderite formed a capped mill scale enclosure where localized corrosion can be further enhanced.

关键词： Pipeline steel Primer paint Mill scale Localized corrosion Siderite precipitation

Monitoring dynamics of defects and single Fe atoms in N-functionalized few-layer graphene by in situ temperature programmed scanning transmission electron microscopy

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第1期31卷 520-530,I0014页

作者： Rosa Arrigo Takeo Sasaki June Callison Diego gianolio Manfred erwin Schuster School of Science Engineering and EnvironmentUniversity of SalfordManchester M54WTUK Diamond Light Source Harwell Science and Innovation CampusDidcot 0X1/ODEUK JEOL UK Ltd.JEOL House 1-2 Silver CourtWatchmeadWelwyn Garden CityHerts AL71LTUK Department of Chemistry University College London20 Gordon StreetLondon WC1H OAJUK UK Catalysis Hub Research Complex at Harwell(RCaH)Rutherford Appleton LaboratoryHarwell Oxon 0X11 OFAUK Johnson Matthey Technology Centre Reading RG49NH.UK

In this study,we aim to contribute an understanding of the pathway of formation of Fe species during top-down synthesis of dispersed Fe on N-functionalized few layer graphene,widely used in *** use X-ray absorption spectroscopy to determine the electronic structure and coordination geometry of the Fe species and in situ high angle annular dark field scanning transmission electron microscopy combined with atomic resolved electron energy loss spectroscopy to localize these,identify their chemical configuration and monitor their dynamics during thermal *** show the high mobility of peripheral Fe atoms,first diffusing rapidly at the trims of the graphene layers and at temperatures as high as 573 K,diffusing from the edge planes towards in-plane locations of the graphene layers forming three-,four-coordinated metal sites and more complexes polynuclear Fe *** process occurs via bond C-C breaking which partially reduces the extension of the graphene ***,the vast majority of Fe is segregated as a metal *** dynamic interconversion depends on the structural details of the surrounding graphitic environment in which these are formed as well as the Fe loading.N species appear stabilizing isolated and polynuclear Fe species even at temperatures as high as 873 *** significance of our results lies on the fact that single Fe atoms in graphene are highly mobile and therefore a structural description of the electroactive sites as such is insufficient and more complex species might be more relevant,especially in the case of multielectron transfer *** we provide the experimental evidence of the formation of these polynuclear Fe-N sites and their structural characteristics.

关键词： HAADF-STEM Single Fe atom sites N-doped Few-layer graphene Dinuclear Fe species