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Towards an L^p potential Theory for Sub-Markovian Semigroups:Kernels and Capacities

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1227-1250页

作者： niels JACOB RenéL.SCHILLING Department of Mathematics University of Wales SwanseaSingleton ParkSwansea SA 2 8 PP.United Kinadom FB 12-Mathematik Philipps-Universitat MarburgD-35032 MarburgGermany

We study in fairly general measure spaces （X,μ） the （non-linear） potential theory of L^p sub-Markovian semigroups which are given by kernels having a density with respect to the underlying measure. In terms of mapping properties of the operators we provide sufficient conditions for the existence （and regularity） of such densities. We give various （dual） representations for several associated capacities and, in the corresponding abstract Bessel potential spaces, we study the role of the truncation property. Examples are discussed in the case of R^n where abstract Bessel potential spaces can be identified with concrete function spaces.

关键词： nonlinear potential theory (r,p)-capacity Bessel potential space gamma.transform sub-Markovian semigroup

proton Exchange Membranes for Fuel Cells Challenges and Recent Developments

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复旦学报（自然科学版） 2005年第5期44卷 666-667页

作者： Jens Oluf Jensen pernille p. Noyé niels J. Bjerrum Materials Science Group Department of Chemistry Technical University of DenmarkMaterials Science Group Department of Chemistry Technical University of DenmarkMaterials Science Group Department of Chemistry Technical University of Denmark

The current technology of proton exchange membrane fuel cells (pEMFC) is based on perfluorosulfonic acid (pFSA) membranes (e. g. Nafion(R)) as electrolyte. It operates on pure hydrogen and oxygen/air at typically 80℃ with high power density and long-term durability. For the membranes to be conductive, a minimum threshold of absorbed water molecules is about 6 to 7 mole per sulfonic site. The highest conductivity is only obtained under fully hydrated conductions, i.e. 21 - 22 mole water per sulfonic acid site. In other words, the proton conductivity is achieved by the locally liquid-like hydrophilic domain of the *** strong dependence of conductivity on the water content in membranes limits the operational temperatureof pEMFC below 100℃.

关键词：质子交换燃料电池隔膜电化学电解液

Compliant Mechanism Synthesis by Using Elastic Similitude

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Chinese Journal of Mechanical Engineering 2015年第4期28卷 769-775页

作者： HANKE Uwe HAMpEL peter COMSA Andrei MODLER niels MODLER Karl-Heinz Institute of Solid Mechanics TU Dresden 01069 Dresden Germany Institute of Lightweight Engineering and polymer Technology TU Dresden 01307 Dresden Germany

Compliant mechanisms have several advantages, especially smaller number of elements and therefore less movable joints. The flexural members furthermore allow an integration of special functions like balancing or locking. Especially fiber reinforced materials exhibit a wide range of function integration considering their compliance in passive as well active applications. To take advantage of compliant elements in applications a robust synthesis tool is needed. The synthesis based on topology optimization method or the pseudo rigid body approach leads to complex structures. Considering the use of fiber reinforced material a synthesis approach which leads to less complex structures is more suitable. For building up simple structures, with only one cantilever beam as compliant element（B） a graphical approach using the elastic similitude is the most efficient method. A step-by-step synthesis procedure is presented to synthesize compliant mechanisms with rotatory joints（R） and prismatic joints（p） to develop RRB/pRB- and RpB-linkages. Using the elastic similitude to implement these results into a graphical synthesis algorithm is the innovation part of this paper. It can be shown that this approach leads to a comfortable handling of beam elements during the synthesis, where the two free parameters can be directly coupled to scale and fix the orientation of the beam element. This advantage inherently shortens the development process. In giving an example the focus lies of the experimental approach, which also shows that the simple BERNOULLI beam model is valid and so the synthesis by using the elastic similitude. The method is presented and discussed by using an application for a cup holder mechanism made of fiber reinforced material.

关键词： Compliant mechanism synthesis elastic similitude

Insect host-parasite coevolution in the light of experimental evolution

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Insect Science 2014年第4期21卷 401-414页

作者： niels A. G. Kerstes Oliver Y. Martin Experimental Ecology Institute for Integrative Biology D‐USYS ETH Zurich Zurich Switzerland

The many ways parasites can impact their host species have been the focus of intense study using a range of approaches. A particularly promising but under-used method in this context is experimental evolution, because it allows targeted manipulation of known populations exposed to contrasting conditions. The strong potential of applying this method to the study of insect hosts and their associated parasites is demonstrated by the few available long-term experiments where insects have been exposed to parasites. In this review, we summarize these studies, which have delivered valuable insights into the evolution of resistance in response to parasite pressure, the underlying mechanisms, as well as correlated genetic responses. We further assess findings from relevant artificial selection studies in the interrelated contexts of immunity, life history, and reproduction. In addition, we discuss a number of well-studied Tribolium castaneum-Nosema whitei coevolution experiments in more detail and provide suggestions for research. Specifically, we suggest that future experiments should also be performed using nonmodel hosts and should incorporate contrasting experimental conditions, such as population sizes or envi- ronments. Finally, we expect that adding a third partner, for example, a second parasite or symbiont, to a host-parasite system could strongly impact （co）evolutionary dynamics.

关键词： artificial selection immunity Nosema reproduction resistance Tribolium

Electrostatic interactions in twisted bilayer graphene

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Nano Materials Science 2022年第1期4卷 27-35页

作者： Tommaso Cea pierre A.pantaleón niels R.Walet Francisco Guinea Imdea Nanoscience Faraday 928015MadridSpain Department of physics and Astronomy University of ManchesterManchesterM13 9PYUK Donostia International physics Center Paseo Manuel de Lardizabal 420018San SebastianSpain

The effects of the long range electrostatic interaction in twisted bilayer graphene are described using the HartreeFock approximation. The results show a significant dependence of the band widths and shapes on electron filling,and the existence of broken symmetry phases at many densities, either valley/spin polarized, with broken sublattice symmetry, or both.

关键词： Graphene Twisted Interactions

Net absorption and liver metabolism of amino acids and heat production of portaldrained viscera and liver in multiparous sows during transition and lactation

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Journal of Animal Science and Biotechnology 2020年第2期11卷 424-439页

作者： Liang Hu niels Bastian Kristensen Lianqiang Che De Wu peter Kappel Theil Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education Institute of Animal NutritionSichuan Agricultural UniversityNo.211Huimin RoadWenjiang DistrictChengduSichuan 611130People’s Republic of China Department of Animal Science Faculty of Science and TechnologyAarhus UniversityDK-8830 TjeleDenmark present address:SEGES Danish pig Research Centre DK-1609 CopenhagenDenmark

Background:Determination of nutrient requirements in the late gestating and lactating sows is essential to optimize sow *** objectives of the present study were to quantify amino acid(AA)fluxes and heat production across portal-drained viscera(pDV)and liver in multiparous sows during transition and ***:Eight second parity sows were fitted with indwelling catheters in the femoral artery and in the mesenteric,portal and hepatic *** hourly sets of blood samples were taken starting 0.5 h before feeding at−10,−3,+3,and+17 d in milk(DIM).Blood gases,plasma metabolites and apparent total tract digestibility(ATTD)of nutrients were ***:Feed intake,the ATTD of DM,energy,nitrogen,fat and crude fiber changed with DIM(ppt for Glu,O2,and urea,all net portal fluxes were positive,and all were affected by DIM(ppling time(ppared with pre partum levels,net portal uptake of AA was 3-63%lower at+3 DIM but 40-100%higher at+17 *** portal fluxes of AA peaked at 1.5 to 2.5 h after feeding except for Glu,and they were positively correlated with changes in sow feed intake across *** net portal recovery was low for Met(49%),Thr(54%),and His(54%)and high for the remaining essential AA(63-69%)and none of them differed across *** hepatic uptake(*** oxidation)of Lys,Thr,Ile,Leu and phe peaked at 0.5 to 2.5 h after feeding,whereas uptake of Trp,Val,and His was constant,while that of Met was close to ***:The net portal recovery was substantially lower for Met,Thr,and His than the remaining essential *** AA oxidation peaks 0.5 to 2.5 h after *** heat production in pDV and liver was approximately two-fold higher at peak lactation compared to other *** study suggests that lysine was the limiting AA in peak lactation but not in early lactation.

关键词： Gestation Heat production Lactation Net hepatic flux Net portal flux Sow

Decreasing nutrient concentrations in soils and trees with increasing elevation across a treelineecotone in Rolwaling Himal, Nepal

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Journal of Mountain Science 2017年第5期14卷 843-858页

作者： Simon DROLLINGER Michael MULLER Timo KOBL niels SCHWAB Jurgen BOHNER Udo SCHICKHOFF Thomas SCHOLTEN Geoecology Department of Geography and Regional Research University of Vienna Vienna Austria Soil Science and Geomorphology Department of Geosciences Uniuersity of Tubingen Tubingen Germany CEN Center for Earth System Research and Sustainability Institute of Geography University of Hamburg Hamburg Germany

At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanisms. The aim of our research was to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors in a near-natural Himalayan treeline ecotone. Soil samples of different soil horizons, litter, decomposition layers, and foliage samples of standing biomass were collected in four altitudinal zones along three slopes, and were analysed for exchangeable cations and nutrient concentrations, respectively. Additionally, soil and air temperature, soil moisture, precipitation, and tree physiognomy patterns were evaluated. Both soil nutrients and foliar macronutrient concentrations of nitrogen(N), magnesium(Mg), potassium(K), and foliar phosphorus(p) decrease significantly with elevation. Foliar manganese(Mn) concentrations, bycontrast, are extraordinarily high at high elevation sites. potential constraining factors on tree growth were identified using multivariate statistical approaches. We propose that tree growth, treeline position and vegetation composition are affected by nutrient limitation, which in turn, is governed by low soil temperatures and influenced by soil moisture conditions.

关键词： Foliar nutrients Himalaya Nitrogen Nutrient cycling podzol Treeline

Metabolic and hepatic effects of liraglutide,obeticholic acid and elafibranor in diet-induced obese mouse models of biopsy-confirmed nonalcoholic steatohepatitis

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World Journal of Gastroenterology 2018年第2期24卷 179-194页

作者： Kirstine S Tolbol Maria NB Kristiansen Henrik H Hansen Sanne S Veidal Kristoffer TG Rigbolt Matthew p Gillum Jacob Jelsing niels Vrang Michael Feigh Gubra Aps Horsholm DK-2970Denmark Department of Biomedical Sciences Faculty of Health SciencesUniversity of CopenhagenCopenhagen DK-2200Denmark Section for Metabolic Imaging and Liver Metabolism The Novo Nordisk Foundation Center for Basic Metabolic ResearchFaculty of Health SciencesUniversity of CopenhagenCopenhagen DK-2200Denmark Department of Chemistry Faculty of ScienceUniversity of CopenhagenCopenhagen DK-2200Denmark

AIM To evaluate the pharmacodynamics of compounds in clinical development for nonalcoholic steatohepatitis(NASH) in obese mouse models of *** Male wild-type C57 BL/6 J mice(DIO-NASH) and Lep^(ob/ob)(ob/ob-NASH) mice were fed a diet high in trans-fat(40%), fructose(20%) and cholesterol(2%) for 30 and 21 wk, respectively. prior to treatment, all mice underwent liver biopsy for confirmation and stratification of liver steatosis and fibrosis, using the nonalcoholic fatty liver disease activity score(NAS) and fibrosis staging system. The mice were kept on the diet and received vehicle, liraglutide(0.2 mg/kg, SC, BID), obeticholic acid(OCA, 30 mg/kg pO, QD), or elafibranor(30 mg/kg pO, QD) for eight weeks. Within-subject comparisons were performed on changes in steatosis, inflammation, ballooning degeneration, and fibrosis scores. In addition, compound effects were evaluated by quantitative liver histology, including percent fractional area of liver fat, galectin-3, and collagen 1 *** Liraglutide and elafibranor, but not OCA, reduced body weight in both models. Liraglutide improved steatosis scores in DIO-NASH mice only. Elafibranor and OCA reduced histopathological scores of hepatic steatosis and inflammation in both models, but only elafibranor reduced fibrosis severity. Liraglutide and OCA reduced total liver fat, collagen 1 a1, and galectin-3 content, driven by significant reductions in liver weight. The individual drug effects on NASH histological endpoints were supported by global gene expression(RNA sequencing) and liver lipid *** DIO-NASH and ob/ob-NASH mouse models show distinct treatment effects of liraglutide, OCA, and elafibranor, being in general agreement with corresponding findings in clinical trials for NASH. The present data therefore further supports the clinical translatability and utility of DIO-NASH and ob/ob-NASH mouse models of NASH for probing the therapeutic efficacy of compounds in preclinical d

关键词： Nonalcoholic steatohepatitis Disease models pathology Fibrosis Liver biopsy Transcriptomics pharmacodynamics Glucagon-like peptide-1 receptor peroxisome proliferator-activated receptor Farnesoid X receptor

Mesenteric traction syndrome in pigs:A single-blinded,randomized controlled trial

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Animal Models and Experimental Medicine 2021年第2期4卷 162-168页

作者： Rune B.Strandby Jens T.F.Osterkamp Rikard Ambrus Amelie Henriksen Jens p.Goetze niels H.Secher Michael p.Achiam Lars-Bo Svendsen Department of Surgical Gastroenterology RigshospitaletUniversity of CopenhagenCopenhagenØDenmark Department of Clinical Biochemistry RigshospitaletUniversity of CopenhagenCopenhagenØDenmark Department of Anaesthesia RigshospitaletUniversity of CopenhagenCopenhagenØDenmark

Background:Mesenteric traction syndrome is commonly observed in patients undergoing upper abdominal surgery and is associated with severe postoperative complications.A triad of hypotension,tachycardia,and facial flushing seems provoked by prostacyclin(pGI 2)release from the gut in response to mesenteric *** administration of nonsteroidal anti-inflammatory drugs(NSAID)inhibits pGI 2 release,stabilizing the hemodynamic ***,we examined the effect of mesenteric traction on splanchnic blood flow in pigs randomized to NSAID or placebo *** and Methods:Twenty pigs were allocated to either ketorolac or pla-cebo *** minutes of manual mesenteric traction was *** 6-keto-pGF1,a stable metabolite of pGI 2,hemodynamic variables,and regional blood flow(laser speckle contrast imaging)to the liver,stomach,small intestine,upper lip,and snout(laser Doppler flowmetry)were recorded prior to traction and 5 and 30 minutes ***:Both groups of pigs presented a decrease in systemic vascular resistance(p.01),mean arterial blood pressure(p.001),and blood flow in the gastric an-trum(p.002).plasma 6-keto-pGF1 did not increase in either group(p.195),and cardiac output,heart rate,central venous pressure,and blood flow to the liver,small intestine,upper lip,and snout remained ***:Mesenteric traction resulted in cardiovascular depression,including re-duced blood flow in the gastric *** 6-keto-pGF1 did not increase,and ketorolac administration did not alter the response to mesenteric *** studies are needed to identify which substance is responsible for eliciting the cardio-vascular response to mesenteric traction in pigs.

关键词： 6-keto-pGF1 gastric blood flow hemodynamics laser speckle contrast imaging mesenteric traction syndrome prostacyclin