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Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： Paul REICHLE Jakob BARZ georg UMLAUF Günter E.M.TOVAR Institute of Interfacial Process Engineering and Plasma Technology(IGVP) University of StuttgartStuttgart 70569Germany Fraunhofer Institute for Interfacial Engineering and Biotechnology(IGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 MPa,6 MPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

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Evolution of C4 Phosphoenolpyruvate Carboxylase： Enhanced Feedback Inhibitor Tolerance Is Determined by a Single Residue

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Molecular Plant 2013年第6期6卷 1996-1999页

作者： Judith Katharina Paulus, Christian Niehus georg Groth Cluster of Excellence on Plant Sciences (CEPLAS) Institute of Biochemical Plant Physiology Heinrich Heine University Düsseldorf Germany

Dear Editor, Phosphoenolpyruvate carboxylase （PEPC） is the essential enzyme for initial carbon fixation in C4 photosynthesis. The C4-PEPC evolved from a non-photosynthetic C3 ancestor by subtle sequence changes resulting in distinctly different kinetic and regulatory characteristics （Svensson et al., 1997）. Malate and aspartate, which are formed from the carboxyla- tion product of PEPC, serve as feedback inhibitors of the PEPC （Wedding et al., 1990）. Higher malate or aspartate concen- trations during C4 photosynthesis require a reduced sensitiv- ity towards the feedback inhibitors of the C4-PEPC （Jacobs et al., 2008）.

关键词： Phosphoenolpyruvate Carboxylase malate C4 photosynthesis Feedback Flaveria Carbon Fixation Residues Residue hydrogen bonds Aspartic Acid peptidase C Aspartate evolution

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Mixed reproduction strategy and polyploidy facilitate dominance of Kobresia pygmaea on the Tibetan Plateau

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Journal of Plant Ecology 2016年第1期9卷 87-99页

作者： Elke Seeber georg Miehe Isabell Hensen Yongping Yang Botany Department Senckenberg Museum of Natural History GörlitzPO Box 300154D-02806 GörlitzGermany Department of Geobotany and Botanical Garden University Halle-WittenbergAm Kirchtor 1D-06108 Halle(Saale)Germany Department of Geography University MarburgDeutschhausstraße 10D-35032 MarburgGermany German Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig Deutscher Platz 5eD-04103 LeipzigGermany Kunming Institute of Botany Chinese Academy of SciencesHeilongtan 650204KunmingChina Present address Department of GeographyUniversity MarburgDeutschhausstraße 10D-35032 MarburgGermany

Aims The sedge Kobresia pygmaea is the dominant species of high-altitude pastures in Tibet,and it is the most important source of forage in animal *** present the first comprehensive reproduction study for this perennial key species that adopts a molecular approach and tests how sexual and vegetative reproduction,as well as ploidy,relate to survival and dominance under harsh *** We assessed inflorescence numbers of *** across two Tibetan alpine pastures with differing grazing *** was tested in untreated diaspores and then following mechanical and chemical *** a 4-year experiment,we assessed diaspore viability and seed bank *** eight microsatellite markers,we recorded multilocus genotypes in hierarchical grids and measured their ploidy using flow *** analysis of variance models were used to analyse data on sexual reproduction,while the complement of the Simpson index and the Shannon diversity index were used to characterize the spatial distribution of multilocus genotypes and clonal *** Findings Inflorescence production was high and differed significantly between years(2010:617±460 SD;2012:2015±1213 SD)but not between grazing *** viability was high(94%)and gradually decreased after 3 and 4 years of storage in the *** not exposed to further scarification failed to germinate,while mechanical and chemical(H2SO4)scarification increased germination to 9 and 44%,*** diversity was high,although in situ germination was rarely *** genotypes intersected and covered a mean area of 0.74 *** individuals were found to be tetraploid,with only 0.8%of all ramets being *** conclude that *** survives on the Tibetan Plateau by employing a mixed reproduction strategy involving both sexual and clonal *** species’adaptability and dominance is further facilitated by its *** pasture restoration usi

关键词： alpine rangelands clonal diversity flow cytometry grazing microsatellite analyses

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From Lung to Brain:Respiration Modulates Neural and Mental Activity

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Neuroscience Bulletin 2023年第10期39卷 1577-1590页

作者： Josh Goheen John A.E.Anderson Jianfeng Zhang georg Northof The Royal Ottawa Mental Health Centre The University of OttawaOttawa K1Z 7K4Canada Department of Cognitive Science Carleton UniversityOttawa K1S 5B6Canada Center for Brain Disorders and Cognitive Sciences Shenzhen UniversityShenzhen 518060China School of Psychology Shenzhen UniversityShenzhen 518060China

Respiration protocols have been developed to manipulate mental states,including their use for therapeutic *** this systematic review,we discuss evidence that respiration may play a fundamental role in coordinating neural activity,behavior,and *** main findings are:(1)respiration affects the neural activity of a wide variety of regions in the brain;(2)respiration modulates different frequency ranges in the brain’s dynamics;(3)different respiration protocols(spontaneous,hyperventilation,slow or resonance respiration)yield different neural and mental effects;and(4)the effects of respiration on the brain are related to concurrent modulation of biochemical(oxygen delivery,pH)and physiological(cerebral blood flow,heart rate variability)*** conclude that respiration may be an integral rhythm of the brain’s neural *** provides an intimate connection of respiration with neuro-mental features like emotion.A respiratory-neuro-mental connection holds the promise for a brain-based therapeutic usage of respiration in mental disorders.

关键词： Respiration Cognition Emotion Heart rate variability Carbon dioxide

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Microfluidic bacterial traps for simultaneous fluorescence and atomic force microscopy

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Nano Research 2017年第11期10卷 3896-3908页

作者： Oliver Peric Melanie Hannebelle Jonathan D. Adams georg E. Fantner Laboratory for Bio-and Nano-Instrumentation Institute of Bioengineering School of Engineering EPFL 1015 Lausanne Switzerland

The atomic force microscope has become an established research tool for imaging microorganisms with unprecedented ***,its use in microbiology has been limited by the difficulty of proper bacterial ***,we have developed a microfluidic device that solves the issue of bacterial immobilization for atomic force microscopy under physiological *** device is able to rapidly immobilize bacteria in well-defined positions and subsequently release the cells for quick sample *** developed device also allows simultaneous fluorescence analysis to assess the bacterial viability during atomic force microscope *** demonstrated the potential of our approach for the immobilization of rod-shaped Escherichia coli and Bacillus *** our device,we observed buffer-dependent morphological changes of the bacterial envelope mediated by the antimicrobial peptide *** approach to bacterial immobilization makes sample preparation much simpler and more reliable,thereby accelerating atomic force microscopy studies at the single-cell level.

关键词： atomic force microscope (AFM) microfabrication microfluidics microbiology correlative microscopy physical immobilization

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Modelling the utility of group testing for public health surveillance

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Infectious Disease Modelling 2021年第1期6卷 1009-1024页

作者： Günther Koliander georg Pichler Acoustics Research Institute Austrian Academy of SciencesWohllebengasse 12-141040ViennaAustria Institute of Telecommunications TU WienGußhausstraße 25/E3891040ViennaAustria

In epidemic or pandemic situations,resources for testing the infection status of individuals may be *** group testing can help to significantly increase testing capabilities,the(repeated)testing of entire populations can exceed the resources of any *** thus propose an extension of the theory of group testing that takes into account the fact that definitely specifying the infection status of each individual is *** theory builds on assigning to each individual an infection status(healthy/infected),as well as an associated cost function for erroneous *** cost function is versatile,e.g.,it could take into account that false negative assignments are worse than false positive assignments and that false assignments in critical areas,such as health care workers,are more severe than in the general *** on this model,we study the optimal use of a limited number of tests to minimize the expected *** specifically,we utilize information-theoretic methods to give a lower bound on the expected cost and describe simple strategies that can significantly reduce the expected cost over currently known strategies.A detailed example is provided to illustrate our theory.

关键词： Group testing Public health surveillance Source coding Rate-distortion theory

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Non-linear affine processes with jumps

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Probability, Uncertainty and Quantitative Risk 2023年第2期8卷 235-266页

作者： Francesca Biagini georg Bollweg Katharina Oberpriller Workgroup Financial and Insurance Mathematics Department of MathematicsLudwig-Maximilians-Universität MünchenTheresienstrasse 3980333 MunichGermany University of Freiburg Ernst-Zermelo-Strasse 179104 FreiburgGermany

We present a probabilistic construction of R^(d)-valued non-linear affine processes with *** a setΘof affine parameters,we define a family of sublinear expectations on the Skorokhod space under which the canonical process X is a(sublinear)Markov process with a non-linear *** yields a tractable model for Knightian uncertainty for which the sublinear expectation of a Markovian functional can be calculated via a partial integro-differential equation.

关键词： Sublinear expectation Non-linear affine processes Dynamic programming PIDE

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Influence of skeletal muscle mass on graft regeneration after living-donor liver transplantation

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Hepatobiliary Surgery and Nutrition 2021年第4期10卷 564-566页

作者： Deniz Uluk Johann Pratschke georg Lurje Department of Surgery Campus CharitéMitte|Campus Virchow-KlinikumCharité-Universitätsmedizin BerlinBerlinGermany

Body composition(BC)is defined as the relative proportion of fat,water,protein,and mineral components in the body and varies greatly among *** skeletal muscle depletion is frequently seen in severely ill patients,sarcopenia,defined as a pathological reduction of skeletal muscle mass(SMM)and strength,is one of the most significant features of the metabolic imbalance related to end stage liver disease(ESLD).

关键词： skeletal liver donor

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Effects of newly devised plasma lice comb on human hair

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Plasma Science and Technology 2019年第12期21卷 78-84页

作者： Lars TEN BOSCH Andreas HUBER Philipp SAUERBIER Robert KOHLER georg AVRAMIDIS Wolfgang VIOL University of Applied Sciences and Arts HAWK Faculty NVon-Ossietzky-Strasse 99/10037085 GottingenGermany Neaspec GmbH Eglfinger Weg 285540 Munich-HaarGermany Wood Biology and Wood Products Faculty of Forest Sciences and Forest EcologyUniversity of GoettingenBüsgenweg 437077 GottingenGermany

A plasma device was developed showing high potential for a pesticide-free treatment of pediculosis. As a first safety assessment of the device was presented earlier, this present paper focuses on the damage introduced to human hair during a plasma treatment for pediculosis control. Therefore, human hairs were treated repeatedly to assess the possible occurring damage developing with increasing treatment durations. To analyse the inflicted changes on human hair examinations using x-ray photoelectron spectroscopy(XPS/ESCA), scanning nearfield optical microscopy(SNOM) and scanning electron microscopy were conducted, to compare the modifications of surface chemistry and mechanical alterations. The investigations revealed a mild impact on the surface chemistry(XPS/SNOM), while more distinct morphological changes on the hair surface could be observed. The authors conclude that an effect of the plasma comb device on the hair during a real-life treatment is negligible, due to the very short contact times during a standard combing procedure for pediculosis control.

关键词： atmospheric pressure plasma dielectric barrier discharge pediculosis SEM SNOM ESCA XPS hair smoothing plasma based pest management

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Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

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Friction 2021年第6期9卷 1766-1775页

作者： Chia-Jui HSU Andreas STRATMANN Simon MEDINA georg JACOBS Frank MÜCKLICH Carsten GACHOT Institute for Engineering Design and Product Development TU WienLehárgasse 6Campus GetreidemarktVienna 1060Austria Chair of Functional Materials Saarland UniversityCampus D3.3Saarbrücken 66123Germany AC2T Research GmbH Viktor-Kaplan-Straße 2/CWiener Neustadt 2700Austria Institute for Machine Elements and Systems Engineering RWTH AachenSchinkelstraße 10Aachen 52062Germany

Laser surface texturing(LST)has been proven to improve the tribological performance of machine *** micro-scale patterns manufactured by LST may act as lubricant reservoirs,thus supplying oil when encountering insufficient ***,not many studies have investigated the use of LST in the boundary lubrication regime,likely due to concerns of higher contact stresses that can occur with the increasing surface *** study aims to examine the influence of LST on the fatigue lifetime of thrust rolling bearings under boundary lubrication.A series of periodic patterns were produced on the thrust rolling bearings,using two geometrically different designs,namely cross and dimple *** oil ISO VG 100 mixed with 0.05 wt%P of zinc dialkyldithiophosphate(ZDDP)was *** bearings with cross patterns reduce the wear loss by two orders of *** patterns not only retain lubricant in the textured pockets but also enhance the formation of an anti-wear *** tribofilm generation may be improved by the higher contact stresses that occur when using the textured ***,in contrast to the negative concerns,the ball bearings with cross patterns were instead found to increase the fatigue life by a factor of three.

关键词： thrust rolling bearing laser surface texturing direct laser interference patterning zinc dialkyldithiophosphate(ZDDP) tribofilm

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