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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

Discrete particle modeling of granular temperature distribution in a bubbling fluidized bed

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Particuology 2012年第4期10卷 428-437页

作者： Yurong He Tianyu Wang niels Deen Martin van Sint Annaland Hans Kuipers Dongsheng Wen Department of Power Engineering College of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyPO Box 5135600 MB EindhovenThe Netherlands School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon El 4NSUK

The discrete hard sphere particle model （DPM） is applied in this work to study numerically the distribu- tions of particle and bubble granular temperatures in a bubbling fluidized bed. The dimensions of the bed and other parameters are set to correspond to those of Miuller et al（2008）. Various drag models and oper- ational parameters are investigated to find their influence on particle and bubble granular temperatures. Various inlet superficial gas velocities are used in this work to obtain their effect on flow characteristics. It is found that the superficial gas velocity has the most important effect on granular temperatures including bubble granular temperature, particle translational granular temperature and particle rotational granular temperature. The drag force model affects more seriously the large scale variables such as the bubble gran- ular temperature. Restitution coefficient influences all granular temperatures to some degree. Simulation results are compared with experimental results by Muller et al. （2008） showing reasonable agreement.

关键词： Bubbling fluidized bedDiscrete hard sphere modelParticle and bubble granular temperature

Laminated Fe-34.5 Mn-0.04C composite with high strength and ductility

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Journal of Materials Science & Technology 2018年第10期34卷 1939-1943页

作者： Yuhui Wang Jianmei Kang Yan Peng Tiansheng Wang niels Hansen Xiaoxu Huang State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University Qinhuangdao 066004 China Riso Campus Technical University of Denmark DK-4000 Roskilde Denmark College of Materials Sdence and Engineering Chongqing University Chongqing 400045 China Department of Mechanical Engneering Technical University of'Denmark DK-2800 Lyngby Denmark

To obtain a good combination of strength and ductility, a laminated composite structure composed of recovered hard lamellae and soft recrystallized lamellae has been produced in a single phase austenitic Fe-34.5 Mn-0.04C steel by cold rolling and partial recrystallization. Enhanced mechanical properties in both strength and ductility have been obtained in the composite structure compared to a fully recrystallized coarse grain structure. A further increase in strength with only minor loss in total elongation has been achieved by a slight cold rolling of the composite structure, which also removes the small yield drop and Luders elongation observed in the composite structure.

关键词： Laminated composite structure Partial recrystallization Constraint effect Strength Ductility

Microstructure and strength of a tantalum-tungsten alloy after cold rolling from small to large strains

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Journal of Materials Science & Technology 2021年第24期83卷 34-48页

作者： Guoqiang Ma Darcy A.Hughes Andrew W.Godfrey Qiang Chen niels Hansena Guilin Wu College of Materials Science and Engineering Chongqing UniversityChongqing400044China Department of Mechanical Engineering Technical University of DenmarkDK-2800KgsLyngbyDenmark Fremont CAUSA Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Southwest Technology and Engineering Research Institute Chongqing400039China Technical University of Denmark Risoe CampusDK-4000RoskildeDenmark Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China

Microstructural evolution of a refractory tantalum-tungsten alloy(Ta-4%W)after cold rolling from small to large von-Mises strains(0.12-2.7)was quantitatively studied using transmission electron *** subdivision was observed to take place at two *** necessary boundaries nearly paralleling to slip planes enclosed volumes further divided by diffuse cells and by remnants of Taylor *** increasing strain,the diffuse cells evolved into clear incidental dislocation boundaries enclosing cells,while the Taylor lattices *** subdivision was thus intermediate between those observed in cell forming and in non-cell forming ***,the average misorientation angle across all boundaries increased while the average boundary spacing *** of the microstructural parameters at each strain level were found to exhibit universal scaling *** microstructural evolution was found closely linking to the observed high strength and strain hardening of this *** on measured microstructural parameters,the flow stress was calculated utilizing linearly addition of the strengthening by solutes,incidental dislocation boundaries(Taylor strengthening)and geometrically necessary boundaries(Hall-Petch equation).The relative contribution of each strength mechanism evolved with increasing strain and with microstructural evolution:solutes and friction stress dominated at small strains while boundaries dominated at larger *** strengths were in close agreement with experimental tension tests and demonstrated an unexpectedly high and continuous parabolic hardening without transition across this large strain range.

关键词： Tantalum Deformation microstructure Geometrically necessary boundaries Taylor lattices Flow stress

A geometric interpretation of the transition density of a symmetric Lévy process

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Science China Mathematics 2012年第6期55卷 1099-1126页

作者： JACOB niels KNOPOVA Victorya LANDWEHR Sandra SCHILLING RenéL. Department of Mathematics Swansea UniversitySingleton ParkSwansea SA28PPUK V.M.Glushkov Institute of Cybernetics NAS of Ukraine 03187KievUkraine Heinrich Heine University Düsseldorf German Diabetes Center at the Heinrich Heine University DüsseldorfLeibniz Center for Diabetes ResearchInstitute of Biometrics and EpidemiologyAuf'm Hennekamp 6540225 DüsseldorfGermany Institut für Mathematische Stochastik Technische Universität Dresden01062 DresdenGermany

We study for a class of symmetric Lévy processes with state space R n the transition density pt(x) in terms of two one-parameter families of metrics, (dt)t>0 and (δt)t>0. The first family of metrics describes the diagonal term pt(0); it is induced by the characteristic exponent ψ of the Lévy process by dt(x, y) = ^(1/2)tψ(x-y). The second and new family of metrics δt relates to ^(1/2)tψ through the formulawhere F denotes the Fourier transform. Thus we obtain the following "Gaussian" representation of the transition density: pt(x) = pt(0)e- δ2t (x,0) where pt(0) corresponds to a volume term related to tψ and where an "exponential" decay is governed by δ2t . This gives a complete and new geometric, intrinsic interpretation of pt(x).

关键词： Levy过程几何解释密度表对称傅里叶变换状态空间两个指标特征指数

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

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Optoelectronics Letters 2008年第2期4卷 140-142页

作者： Robert Schmitt Tilo Pfeifer Frank Depiereux niels Knig Fraunhofer Institute for Production Technology (IPT) Steinbachstrasse 17 52074 Aachen Germany

Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.

关键词：纤维光干扰术光检测技术测量方法

Influence of rolling friction on single spout fluidized bed simulation

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Particuology 2012年第5期10卷 582-591页

作者： Christoph Goniva Christoph Kloss niels G. Deen Johannes A.M.Kuipers Stefan Pirker Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinz Austria DCS Computing GmbH Linz Austria Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinz Austria Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinzAustria Institute of Fluid Mechanics and Heat Transfer Johannes Kepler UniversityLinzAustria

In this paper we study the effect of rolling friction on the dynamics in a single spout fluidized bed using Discrete Element Method （DEM） coupled to Computational Fluid Dynamics （CFD）. In a first step we neglect rolling friction and show that the results delivered by the open source CFD-DEM framework applied in this study agree with previous simulations documented in literature. In a second step we include a rolling friction sub-model in order to investigate the effect of particle non-sphericity. The influence of particle-particle as well as particle-wall rolling friction on the flow in single spout fluidized bed is studied separately. Adequate rolling friction model parameters are obtained using first principle DEM simulations and data from literature. Finally, we demonstrate the importance of correct modelling of rolling friction for coupled CFD-DEM simulations of spout fluidized beds. We show that simulation results can be improved significantly when applying a rolling friction model, and that experimental data from literature obtained with Positron Emission Particle Trackin~ fPEPT） technique can be satisfactorily reoroduced.

关键词： CFD-DEMOpen sourceRolling frictionSpout fluidized bedNon-sphericity

Signaling transduction pathways involved in basophil adhesion and histamine release

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Chinese Medical Journal 2006年第2期119卷 122-130页

作者： SHA Quan Lars K. Poulsen Jens Gerwien nielsФdum Per Stahl Skov Allergy Unit National University Hospital Copenhagen Denmark Allergy and Immunology Research Center and Department of Medical Immunology Anhui Medical University Hefei 230032 China Institute of Medical Microbiology and Immunology University of Copenhagen Copenhagen Denmark Reference Laboratory National University Hospital Copenhagen Denmark

Background Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles of β1 and β2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase （PI3K）, src-kinases and extracellular signal regulated kinase （ERK）1/2 in basophil adhesion and histamine release （HR）. Methods Basophils （purity of 10%-50%） were preincubated with anti-CD29 or anti-CD 18 blocking antibodies before used for adhesion study. Basophils were preincubated with the pharmacological inhibitors wortmannin, PP1, PD98059 before used for adhesion and HR study. Cell adherence to bovine serum albumin （BSA） or fibronectin （Fn） was monitored using cell associated histamine as a basophil marker and the histamine was measured by the glass fiber assay. Results Basophil spontaneous adhesion to Fn was inhibited by anti-CD29. Interleukin （IL）-3, granulocyte/macrophage colony stimulating factor （GM-CSF） induced adhesion to BSA was inhibited by anti-CD18. Wortmannin at 1 μmol/L and PP1 at 20 μmol/L strongly interfered with, whereas PD98059 at 50μmol/L weakly inhibited basophil spontaneous adhesion to Fn. One μmol/L wortmannin strongly inhibited IL-3, IL-5, GM-CSF and anti-IgE induced adhesion to BSA. PP1 at 20 μmol/L partly inhibited anti-IgE induced adhesion. Fifty μmol/L PD98059 marginally inhibited IL-5, weakly inhibited anti-IgE, partly inhibited GM-CSF induced adhesion. Wortmannin, PP1 and PD98059 inhibited anti-IgE （1：100 or 1：1000） induced basophil HR in a dose dependent manner. They inhibited calcium ionophore A23187 （10 μmol/L, 5 μmol/L） induced basophil HR in a dose dependent manner, but to different extend with PP1 being the most efficient. Conclusions Basophil spontaneous adhesion to Fn is mediated by β 1-integrins whereas cytokine induced adhesion to BSA is m

关键词： basophil signaling transduction adhesion histamine release

Strategies for combating bacterial biofilm infections

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International Journal of Oral Science 2015年第1期7卷 1-7页

作者： Hong Wu Claus Moser Heng-Zhuang Wang niels Hφiby Zhi-Jun Song Department of Clinical Microbiology Rigshospitalet University Hospital of Copenhagen Department of International Health Immunology &Microbiology University of Copenhagen Department of Clinical Microbiology Slagelse Hospital

Formation of biofilm is a survival strategy for bacteria and fungi to adapt to their living environment, especially in the hostile environment. Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the difficulties for the clinical treatment of biofilm infections. Clinical and laboratory investigations demonstrated a perspicuous correlation between biofilm infection and medical foreign bodies or indwelling devices. Clinical observations and experimental studies indicated clearly that antibiotic treatment alone is in most cases insufficient to eradicate biofilm infections. Therefore, to effectively treat biofilm infections with currently available antibiotics and evaluate the outcomes become important and urgent for clinicians. The review summarizes the latest progress in treatment of clinical biofilm infections and scientific investigations, discusses the diagnosis and treatment of different biofilm infections and introduces the promising laboratory progress, which may contribute to prevention or cure of biofilm infections. We conclude that, an efficient treatment of biofilm infections needs a well-established multidisciplinary collaboration, which includes removal of the infected foreign bodies, selection of biofilm-active, sensitive and well-penetrating antibiotics, systemic or topical antibiotic administration in high dosage and combinations, and administration of anti-quorum sensing or biofilm dispersal agents.

关键词： antibiotic resistance antimicrobial treatments bacterial biofilm chronic infection