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Effects of plant-soil feedback on tree seedling growth under arid conditions

Journal of Plant Ecology 2011年第4期4卷 193-200页

作者： Seline S.Meijer milena holmgren Wim H.Van der Putten Resource Ecology Group Wageningen UniversityPO Box 476700 AA WageningenThe Netherlands University College Dublin Forestry Agriculture&Food Science CentreUniversity College DublinBelfieldDublin 4Ireland World Agroforestry Centre(ICRAF) PO Box 30798LilongweMalawi Department of Terrestrial Ecology Netherlands Institute of Ecology(NIOO-KNAW)PO Box 506708 PB WageningenThe Netherlands Laboratory of Nematology Wageningen UniversityPO Box 81236700 ES WageningenThe Netherlands

Plants are able to influence their growing environment by changing biotic and abiotic soil *** soil conditions in turn can influence plant growth conditions,which is called plant–soil ***–soil feedback is known to be operative in a wide variety of ecosystems ranging from temperate grasslands to tropical rain ***,little is known about how it operates in arid *** examined the role of plant–soil feedbacks on tree seedling growth in relation to water availability as occurring in arid ecosystems along the west coast of South *** In a two-phased greenhouse experiment,we compared plant–soil feedback effects under three water levels(no water,10%gravimetric moisture and 15%gravimetric moisture).We used sterilized soil inoculated with soil collected from northwest Peru(Prosopis pallida forests)and from two sites in north-central Chile(Prosopis chilensis forest and scrublands without ***).Important Findings Plant–soil feedbacks differed between plant species and soil origins,but water availability did not influence the feedback ***–soil feedbacks differed in direction and strength in the three soil origins ***–soil feedbacks of plants grown in Peruvian forest soil were negative for leaf biomass and positive for root *** contrast,feedbacks were neutral for plants growing in Chilean scrubland soil and positive for leaf biomass for those growing in Chilean forest *** results show that under arid conditions,effects of plant–soil feedback depend upon ***,the results suggest that plant–soil feedback can influence trade-offs between root growth and leaf biomass investment and as such that feedback interactions between plants and soil biota can make plants either more tolerant or vulnerable to *** on dissecting plant–soil feedbacks into aboveground and belowground tissue responses,we conclude that plant–soil feedback can enhance plant colonization in some arid eco

关键词： biomass allocation dry forest facilitation Prosopis South America water pulse

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Outrunning the Red Queen： bystander activation as a means of outpacing innate immune subversion by intracellular pathogens

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Cellular & Molecular Immunology 2017年第1期14卷 14-21页

作者： Alicia M holmgren Cameron A McConkey Sunny Shin Depatment of Microbiology Perelman School of Medicine University of Pennsylvania Philadelphia PA 19104-6060 USA Immunology Graduate Group Perelman School of Medicine University of Pennsylvania Philadelphia PA 19104-6060 USA

Originally described by the late evolutionary biologist Leigh Van Valen, the Red Queen hypothesis posits that the evolutionary arms race between hosts and their pathogens selects for discrete, genetically encoded events that lead to competitive advantages over the other species. Examples of immune evasion strategies are seen throughout the co-evolution of the mammalian immune system and pathogens, such as the enzymatic inactivation of nuclear factor-KB signaling or host translation by pathogen-encoded virulence factors. Such immunoevasive maneuvers would be expected to select for the evolution of innate immune counterstrategies. Recent advances in our understanding of host immunity and microbial pathogenesis have provided insight into a particular innate immune adaptation, termed bystander activation. Bystander activation occurs as a consequence of infected cells alerting and instructing neighboring uninfected cells to produce inflammatory mediators, either through direct cell contact or paracrine signals. Thus, bystander activation can allow the immune system to overcome the ability of pathogens to disarm immune signaling in directly infected cells. This review presents an overview of the general hallmarks of bystander activation and their emerging role in innate immunity to intraceUular pathogens, as well as examples of recent mechanistic discoveries relating to the bystander activation during infection with specific pathogens relevant to human health and disease.

关键词： cell-cell communication cGAS exosomes gap junctions inflammasomes innate immunity

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Defining a mountain landscape characterized by grazing using actor perception, governmental strategy, and environmental monitoring data

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Journal of Mountain Science 2019年第7期16卷 1691-1701页

作者： Wiebke NEUMANN Camilla SANDSTROM Lina holmgren Goran ERICSSON Department of Wildlife Fish and Environmental StudiesSwedish University of Agricultural Science90183 Ume&Sweden Department of Political Sciences Ume&University90183 UmeaSweden

In multi-functional mountainous landscapes worldwide,conservation of natural values is a major ***,pro-active policies can be a way *** Environmental Quality Objectives(EQO)to solve environmental problems for future generations,however,often wrestle with being too visionary and lacking specificity,which complicates their *** EQO“A Magnificent Mountain Landscape”that has been adopted by the Swedish Parliament in 1999 to preserve the pristine mountain environment in Sweden,experiences all these *** aid its implementation,we studied the conditions and processes needed to define,to evaluate,and to preserve its goals across the Swedish mountain chain,using one of its milestone targets(a landscape characterized by grazing)as a study *** qualitative and quantitative methods,we analyzed three types of data:1)referral responses to the governmental strategy document,2)interviews with relevant actors,and 3)environmental monitoring data(reindeer position data).Nationally,our results suggest a need for geographical differentiation to match regional/local ***,difference in both perception and definition of the milestone target among the actors hinders the formulation,monitoring,and evaluation of a common *** to a culture-nature divide,we found that a“within as a user”and“from the outside as an observer”perspective influenced suggested ***,we found a need for better defining whether the goal is maintaining current conditions or restoring previous *** result supports the use of animal position data as a decision support tool to monitor and to aid evaluation of the *** the number of actors involved and conflicts of interests present,we suggest the application of a structured decision process to accomplish agreements on a common ***,environmental monitoring data can aid a“landscape assessment step”as a natural part in the decision process to target landscape management acti

关键词： Milestone target Structured decision process Reindeer herding Herbivory Environmental Conservation strategy Sweden

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Effect of phosphate on heterogeneous Fenton oxidation of catechol by nano-Fe_(3)O_(4):Inhibitor or stabilizer?

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Journal of Environmental Sciences 2016年第1期28卷 69-76页

作者： Xiaofang Yang Jie He Zhongxi Sun Allan holmgren Dongsheng Wang Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China School of Chemistry and Chemical Engineering University of JinanJinan 250022China Chemical Engineering Department of CivilEnvironmental and Natural Resources EngineeringLulea University of TechnologySE-971 87Sweden

The effect of phosphate on adsorption and oxidation of catechol, 1,2-dihydroxybenzene,in a heterogeneous Fenton system was investigated. In situ attenuated total reflectance infrared spectroscopy（ATR-FTIR） was used to monitor the surface speciation at the nano-Fe_3O_4 catalyst surface. The presence of phosphate decreased the removal rate of catechol and the abatement of dissolved organic compounds, as well as the decomposition of H2O2. This effect of phosphate was mainly due to its strong reaction with surface sites on the iron oxide catalyst. At neutral and acid pH, phosphate could displace the adsorbed catechol from the surface of catalyst and also could compete for surface sites with H2O2. In situ IR spectra indicated the formation of iron phosphate precipitation at the catalyst surface. The iron phosphate surface species may affect the amount of iron atoms taking part in the catalytic decomposition of H2O2 and formation of hydroxyl radicals,and inhibit the catalytic ability of Fe3O4 catalyst. Therefore, phosphate ions worked as stabilizer and inhibitor in a heterogeneous Fenton reaction at the same time, in effect leading to an increase in oxidation efficiency in this study. However, before use of phosphate as pH buffer or H2O2 stabilizer in a heterogeneous Fenton system, the possible inhibitory effect of phosphate on the actual removal of organic pollutants should be fully considered.

关键词： Heterogeneous Fenton oxidation Adsorption ATR-FTIR Interface mechanism

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Effects of Carbon Content and Solidification Rate on the Thermal Conductivity of Grey Cast Iron

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Tsinghua Science and Technology 2008年第2期13卷 170-176页

作者： Daniel holmgren Attila Diószegi Ingvar L. Svensson Department of Mechanical Engineering and Component Technology Jnkping University

The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimilar cooling rates. The cooling rates together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent, and the fraction of the former primary solidified austenite transformed into pearlite. The results show that the optimal thermal transport properties are obtained at medium cooling rates. Equations are given for the thermal conductivity of pearlite, solidified as pre-eutectic austenite, and the eutectic of grey iron. The thermal conductivity of pearlitic grey iron is modelled at both room temperature and elevated temperatures with good accuracy.

关键词： grey iron thermal conductivity thermal diffusivity carbon content carbon equivalent color etching graphite morphology eutectic cell size

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Effects of carbon content and solidification rate on thermal conductivity of grey cast iron

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China Foundry 2007年第3期4卷 210-214页

作者： Daniel holmgren Attila Diószegi Ingvar L.Svensson Jnkping University Dept. of Mechanical Engineering/Component TechnologyJnkpingSE-551 11Sweden

The thermal conductivity or diffusivity of pearlitic grey irons with various carbon contents is investigated by the laser flash method. The materials are cast in controlled thermal environments and produced in three dissimilar cooling rates. The cooling rate together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content,the carbon equivalent and the fraction of former primary solidified austenite transformed into pearlite. The work shows that optimal thermal transport properties are obtained at medium cooling rates. Equations describing the thermal conductivity of pearlite,solidified as pre-eutectic austenite,and the eutectic of grey iron are derived. The thermal conductivity of pearlitic grey iron is modeled at both room temperature and elevated temperature with good accuracy.

关键词： grey iron thermal conductivity thermal diffusivity carbon content carbon equivalent colour etching graphite morphology eutectic cell size primary austenite cooling rate

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Thioredoxin and glutaredoxin-mediated redox regulation of ribonucleotide reductase

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World Journal of Biological Chemistry 2014年第1期5卷 68-74页

作者： Rajib Sengupta Arne holmgren Division of Biochemistry Department of Medical Biochemistry and Biophysics Karolinska Institute SE-17177 Stockholm Sweden

Ribonucleotide reductase(RNR), the rate-limitingenzyme in DNA synthesis, catalyzes reduction of thedifferent ribonucleotides to their corresponding deoxyri-bonucleotides. The crucial role of RNR in DNA synthesishas made it an important target for the development ofantiviral and anticancer drugs. Taking account of the re-cent developments in this field of research, this reviewfocuses on the role of thioredoxin and glutaredoxin sys-tems in the redox reactions of the RNR catalysis.

关键词： Ribonucleotide reductase Thioredoxin Glutaredoxin DNA synthesis Thiol disulfides Replication

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ATR-FTIR在研究环境固液微界面吸附过程中的应用

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化学进展 2010年第6期22卷 1185-1194页

作者：杨晓芳王东升孙中溪刘会娟 Allan holmgren 中国科学院生态环境研究中心北京100085 Department of Chemical Engineering and Geosciences Lule University of Technology 济南大学化学与化工学院济南250022

微界面吸附过程是许多环境微界面反应的初始步骤或关键步骤。通过原位分析方法实时研究环境微界面吸附过程,可以获得更直接的界面反应信息和更可靠的反应机制证据,对于认识污染物在环境中分配转化和迁移传输规律有着重要意义。衰减全反... 详细信息

微界面吸附过程是许多环境微界面反应的初始步骤或关键步骤。通过原位分析方法实时研究环境微界面吸附过程,可以获得更直接的界面反应信息和更可靠的反应机制证据,对于认识污染物在环境中分配转化和迁移传输规律有着重要意义。衰减全反射红外光谱技术由于其独特的采样原理、简便的制样方法和广泛的适应性,正逐渐成为研究微界面反应的一个有力工具。本文在简要介绍原位衰减全反射红外光谱技术原理的基础上,综述了其在环境微界面的吸附过程,尤其是矿物-水界面吸附过程中的应用,并探讨了其在环境微界面过程研究中的发展前景。

关键词：环境微界面矿物吸附 ATR-FTIR

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Lattice QCD Production on a Commodity Cluster at Fermilab

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International Conference on Computing in High Energy and Nuclear Physics 2001年第1期 57-60页

作者： D.holmgren P.Mackenzie 等 FermiNationalAcceleratorLaboratory BataviaILUSA

Large scale QCD Monte Carlo calculations have typically been performed on either commercial supercomputers or specially built massively parallel computers such as Fermilab's *** clusters equipped with high performance networking equipment present an attractive alternative,achieving superior performance to price ratios and offering clear upgrade *** describe the construction and results to date of Fermilab's prototype production cluster,which consists of 80 dual Pentium Ⅲsystems interconnected with Myrinet networking *** describe software tools and techniques we have developed for operating system installation and *** discuss software optimizations using the Pentium's built-in parallel computation facilities(SSE),Finally,we present short and long term plans for the construction of larger facilities.

关键词：格子QCD 费米实验室商品聚类

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Selenium and the Thioredoxin and Glutaredoxin Systems

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Biomedical and Environmental Sciences 1997年第2期10卷 271-279页

作者： MIKAEL BJORNSTEDT SUSHIL KUMAR LINDA BJ■RKHEM GIANNIS SPYROU AND ARNE holmgren(The Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, S-171 77 Stockholm, Sweden Department of Bioscience, Medical Nobel Institute for Biochemistry Department of Medical Biochemistry and Biophysics Karolinska Institute Stockholm Sweden.

Thioredoxin (Trx) is a small ubiquitous dithiol protein which together with the FADcontaining enzyme thioredoxin reductase (TR) and NADPH (the Trx system) is a hydrogen donor for ribonucleotide reductase essential for DNA synthesis and a general protein disulfide reductase involved in redox regulation. Selenite, selenodiglutathione (GS-Se-SG) and selenocystine are efficiently reduced by thioredoxins and also directly by NADPH and mammalian TR but not by the E. coli enzyme. Incubation of selenite or GS-Se-SG with the Trx system or with mammalian TR results in a rapid formation of selenide, which by redox cycling with oxygen may cause a large non-stoichiometric oxidation of NADPH. Selenocystine is efficiently reduced into two molecules of the selenol amino acid selenocysteine by mammalian TR with a Km-value (6μmol·L-1 ) and a high turnover number (kcat, 3200 min-1) almost identical to the natural substrate Trx-S2. TR also directly reduces lipid hydroperoxides and this peroxidase reaction is strongly stimulated by the presence of catalytic amounts of free selenocysteine. Glutaredoxin (Grx) which catalyzes GSH dependent disulfide reduction also via a redox-active disulfide and Trx are both efficient electron donors to the hut-nan plasrna glutathione peroxidase providing a mechanism by which human plasma glutathione peroxidase may reduce hydroperoxides in an environment almost free from glutathione. Selenate is reduced by Grx and Trx in the presence of GSH. The DNA-binding of the transcription factor AP-1 is strongly inhibited by GS-Se-SG and selenite. Furtherrnore, selenide formed by TR-mediated reduction of selenite and GS-Se-SG inhibits lipoxygenase and changes the electron spin resonance spectrum of the active site iron. Mammalian TR with two subunits of 57 kDa has recently been cloned and shown to be homologous to glutathione reductase. The rat enzyme contains a selenocysteine residue in a unique Cterminal position and a conserved SEClS sequence directing insertion

关键词： NADPH Selenium and the Thioredoxin and Glutaredoxin Systems GSH USA ADF

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