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Effectiveness of seed dispersal by ants in a Neotropical tree

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Integrative Zoology 2011年第3期6卷 222-226页

作者： britta Denise HARDESTY Smithsonian Tropical Research Institute BalboaAncónPanama and Department of Plant BiologyUniversity of GeorgiaAthensGeorgiaUSA and Commonwealth Scientific and Industrial Research Organization(CSIRO)Ecosystem SciencesAthertonQldAustralia

Seed dispersal and subsequent recruitment is the template on which forest regeneration takes ***,considering the scale over which ecological processes occur is key for understanding the overall impact of various dispersal *** explore leafcutter ant(Atta colombica)dispersal effectiveness in space and time,seed movement and subsequent recruitment of a large-seeded predominately vertebrate-dispersed tree,Simarouba amara(***),was investigated on Barro Colorado Island,*** each of 218 reproductive-sized adults(>20 cm diameter at breast height),presence or absence of a leafcutter ant colony was noted,with extensive checks for Atta activity taking place at or in close proximity to seed and seedling transects,which extended 4 cardinal directions for 30 m from each reproductive female tree(n=74).Only at 2 *** trees were nests observed,and in these areas a dense *** seedling carpet was *** nearby nest and dump sites might increase local *** recruitment in the short term,mortality at these sites is complete or nearly ***,the seed dispersal effectiveness by leafcutter ants appears to be ephemeral and likely contributes inconsequentially to the long-term recruitment and distribution patterns of the *** finding highlights the importance of evaluating disperser effectiveness at ecologically relevant spatiotemporal scales.

关键词： Atta colombica Barro Colorado Island seed dispersal effectiveness Simarouba amara

Innate and adaptive immunity in inflammatory bowel disease

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World Journal of Gastroenterology 2011年第27期17卷 3178-3183页

作者： britta Siegmund Martin Zeitz Medical Department I (Gastroenterology/Rheumatology/Infectious Diseases) Campus Benjamin FranklinCharité Universittsmedizin Berlin Hindenburgdamm 3012203 BerlinGermany

Inflammatory bowel diseases are the consequence of a dysregulated mucosal immune system. The mucosal immune system consists of two arms, innate and adaptive immunity, that have been studied separately for a long time. Functional studies from in vivo models of intestinal inflammation as well as results from genome-wide association studies strongly suggest a crossregulation of both arms. The present review will illustrate this interaction by selecting examples from innate immunity and adaptive immunity, and their direct impact on each other. Broadening our view by focusing on the cross-regulated areas of the mucosal immune system will not only facilitate our understanding of disease, but furthermore will allow identification of future therapeutic targets.

关键词： Inflammatory bowel diseases Immune system

Extraluminal factors contributing to inflammatory bowel disease

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World Journal of Gastroenterology 2011年第5期17卷 572-577页

作者： Arvind Batra Thorsten Stroh britta Siegmund Charité Universittsmedizin Berlin Campus Benjamin FranklinMedical Department I(Gastroenterology/Rheumatology/Infectious Diseases)Hindenburgdamm 3012200 BerlinGermany

Many identified and yet unknown factors contribute to the pathogenesis of inflammatory bowel disease(IBD).The genome-wide association studies clearly support the earlier developed concept that IBD occurs in genetically predisposed individuals who are exposed to distinct environmental factors,which together result in dysregulation of the mucosal immune ***,the majority of previous studies have focused on the immune response within the intestinal *** present review aims to emphasize the contribution of three extraluminal structures to this inflammatory process,namely the mesenteric fat tissue,the lymphatics and the *** our view across the intestinal wall will not only facilitate our understanding of the disease,but will also us to identify future therapeutic targets.

关键词： Inflammatory bowel disease Extraluminalstructures Mesenteric fat tissue Lymphatics Microvas-culature

Habitat differences in dung beetle assemblages in an African savanna–forest ecotone:implications for secondary seed dispersal

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Integrative Zoology 2011年第2期6卷 81-96页

作者： britta K.KUNZ Frank-Thorsten KRELL Department of Animal Ecology and Tropical Biology Theodor-Boveri Institute of BiosciencesWürzburgGermany Department of Zoology Denver Museum of Nature&ScienceDenverColoradoUSA

The probability and pattern of secondary seed dispersal by dung beetles(Scarabaeinae)depend on their community structure and composition at the site of primary deposition,which,in turn,seem to be strongly determined by ***,we expected pronounced differences in secondary seed dispersal between forest and savanna in the northern Ivory Coast,West *** found 99 dung beetle species at experimentally exposed dung piles of the olive baboon(Papio anubis(Lesson,1827)),an important primary seed disperser in West ***-six species belonged to the roller and tunneler guilds,which are relevant for secondary seed *** species showed a clear habitat *** to the Neotropics,species number and abundance were much higher in the savanna than in the *** and tunnelers each accounted for approximately 50%of the individuals in the savanna,but in the forest rollers made up only 4%.Seeds deposited into the savanna by an omnivorous primary disperser generally have a higher overall probability of being more rapidly dispersed secondarily by dung beetles than seeds in the ***,rollers disperse seeds over larger *** contrast to other studies,small rollers were active in dispersal of large seeds,which were seemingly mistaken for dung *** results suggest that rollers can remove seeds from any plant dispersed in primate dung in this ecosystem.

关键词： Africa baboon defecations guild differences Scarabaeidae secondary seed dispersal.

Multiphase-field modelling of concurrent grain growth and coarsening in complex multicomponent systems

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Journal of Materials Science & Technology 2020年第10期42卷 215-229页

作者： P.G.Kubendran Amos Ramanathan Perumal Michael Selzer britta Nestler Institute of Applied Materials(1AM-CMS) Karlsruhe Institute of Technology(KIT)Strasse am Forum 776131 KarlsruheGermany Institute of Digital Materials Science(IDM) Karlsruhe University of Applied SciencesMoltkestr.3076133 KarlsruheGermany

Phase-field modelling of microstructural evolution in polycrystalline systems with phase-associated grains has largely been confined to continuum-field *** this study,a multiphase-field approach,with a provision for introducing grain boundary and interphase diffusion,is extended to analyse concurrent grain growth and coarsening in multicomponent polycrystalline microstructures with chemically-distinct *** effect of the number of phases and components on the kinetics of evolution is investigated by considering binary and ternary systems of duplex and triplex microstructures,along with a single phase *** is realised that the mere increase in the number of phases minimises the rate of concurrent grain growth and ***,the effect of components is substantially dependent on the respective kinetic *** work unravels that the disparity in the influence of phases and components is primarily due to the corresponding change introduced in the transformation *** the raise in number of phases convolutes the diffusion paths,the increase in number of component effects the rate of evolution through the interdiffusion,which introduces interdependency in the diffusing ***,the role of phase-fractions on the transformation rate of triplex microstructure is studied,and correspondingly,the interplay of interface-and diffusion-governed evolution is elucidated.A representative evolution of three-dimensional triplex microstructure with equal phase-fraction is comparatively analysed with the evolution of corresponding two-dimensional setup.

关键词： Concurrent grain growth and coarsening Duplex and triplex microstructure Microstructural coarsening Multiphase grain growth Multiphase-field modelling

Morphological stability of three-dimensional cementite rods in polycrystalline system:A phase-field analysis

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Journal of Materials Science & Technology 2021年第18期77卷 252-268页

作者： Tobias Mittnacht P.G.Kubendran Amos Daniel Schneider britta Nestler Institute of Applied Materials(IAM-CMS) Karlsruhe Institute of Technology(KIT)Strasse am Forum 776131 KarlsruheGermany Institute of Digital Materials Science(IDM) Karlsruhe University of Applied SciencesMoltkestr.3076133 KarlsruheGermany Department of Metallurgical and Materials Engineering National Institute of TechnologyTiruchirappalli-620015Tamil NaduIndia

Transformations accompanying shape-instability govern the morphological configuration and distribution of the phases in a *** to the influence of the microstructure on the properties of a material,in the present work,the stability of three-dimensional rods in a‘representative'polycrystalline system is extensively analysed.A multiphase-field model,which recovers the physical laws and sharpinterface relations,and includes grain boundary diffusion,is adopted to investigate the morphological evolution of the ***,the efficiency of the numerical approach is ensured by establishing the volume-preserving chemical equilibrium through the incorporation TCFe8(CALPHAD)data and solving phase-field evolution in the Allen-Cahn *** morphological evolution of the rod in the representative multiphase system exhibits a unique transformation mechanism which is significantly different from the evolution of an isolated *** is realised that,in a polycrystalline arrangement,irrespective of the initial size of the rod,the shape-change begins with the energy-minimising events at the triple *** early transformation renders a characteristic morphology at the longitudinal ends of the structure,which introduces sufficient driving-force through the curvature-difference for the subsequent morphological *** continued mass transfer to the terminations,ultimately,breaks-off the rod into separate entities that are entangled in the grain *** increase in the aspect ratio of the rod,it is identified that the source of mass transfer,which turns into the ovulation site,shifts from the *** increases the number of fragmentation events and introduces satellite *** size of the satellite particle is dictated by a definite ovulation criterion,which is ascertained by examining the transformation of different-sized rods.A comprehensive understanding of the transformation kinetics and mechanism governing the mo

关键词： Shape instability Pearlite spheroidization Sub-critical annealing Phase-field simulations

Assessing effects of land use and land cover changes on hydrological processes and sediment yield in the Xunwu River watershed, Jiangxi Province, China

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Frontiers of Earth Science 2022年第3期16卷 819-833页

作者： Guihua LIU britta SCHMALZ Qi ZHANG Shuhua QI Lichao ZHANG Shiyu LIU School of Geography and Environment Key Laboratory of Poyang Lake Wetland and Watershed Research(Ministry of Education)Jiangxi Normal UniversityNanchang 330022China Department of Civil and Environmental Engineering Key Laboratory of Engineering Hydrology and Water ManagementTechnical University of DarmstadtDarmstadt 64287Germany Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China College of Land Resources and Environment Jiangxi Agricultural UniversityNanchang 330045China Jiangxi Key Laboratory of Soil Erosion and Prevention Jiangxi Institute of Soil and Water ConservationNanchang 330029China

The effects of land use and land cover changes on hydrological processes and sediment yield are important issues in regional *** Xunwu River catchment located in the red soil hilly region of southern China has experienced drastic land use changes in the past 30 years,with orchard increases of approximately 42%and forest decreases of approximately 40%.These changes have resulted in some alterations of runoff and sediment *** study aims to evaluate effects of land use/land cover on runoff and sediment yield in the Xunwu River *** SWAT model(Soil and Water Assessment Tool)was used for runoff and sediment simulation,and the results met the requirements of the model acceptance based on evaluation statistics of R^(2)(the coefficient of determination),PBIAS(percent bias),and NSE(Nash-Sutcliffe efficiency).Four land use scenarios representing the gradual expansion of orchards in the past 26 years were developed for assessment of hydrological processes and sediment yield *** a result,both runoff and sediment yield were changed insignificantly with decrease rates of 1.84%and 5.29%,*** addition,surface runoff accounts for the largest share of the runoff components,but the lateral flow changed more than other runoff components with a decrease rate of 10.96%.The results show that orchard expansion does not reveal severe water and soil *** study can contribute to the rational utilization of land and water resources in the red soil hilly area of southern Jiangxi Province.

关键词： land use change orchard expansion red soil hilly region SWAT runoff sediment

Georgia O'Keeffe, 1887-1986

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hsa-mir-183 is frequently methylated and related to poor survival in human hepatocellular carcinoma

作者： britta Benke.

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World Journal of Gastroenterology 2017年第9期23卷 1568-1575页

作者： Sumadi Lukman Anwar Till Krech britta Hasemeier Elisa Schipper Nora Schweitzer Arndt Vogel Hans Kreipe Reena Buurman britta Skawran Ulrich Lehmann Ulrich Lehmann Institute of PathologyMedizinische Hochschule Hannover Department of Surgery Faculty of Medicine Universitas Gadjah Mada Department of Gastroenterology Hepatology and EndocrinologyMedizinische Hochschule Hannover Institute of Human Genetics Medizinische Hochschule Hannover

To screen clinically relevant microRNAs (miRNAs) silenced by DNA methylation in human hepatocellular carcinoma (HCC).METHODSKnockdown of DNA methyltransferases (DNMTs) using siRNAs and miRNA profiling in HCC cell lines were performed to identify DNA hypermethylation-mediated miRNA downregulation. Confirmation using individual quantitative real-time PCR (qRT-PCR) assays was then performed followed by DNA methylation quantification at the promoter of the miRNA genes. Quantification of DNA methylation and miRNA expression was then performed in primary HCC tumor samples and related with clinicopathological *** profiling after DNMT knockdown in HCC cell lines revealed upregulation of miR-23, miR-25 and miR-183. After qRT-PCR confirmation and CpG island methylation quantification of these miRNAs in cell lines, further analysis in primary HCC specimens showed that hsa-miR-183 is hypermethylated in 30% of HCC (n = 40). Expression of mature miR-183 showed an inverse correlation with DNA methylation levels. In HCC cells, DNMT knockdown and 5-aza-2’-deoxycytidine treatment reduced methylation and stimulated expression of miR-183. In HCC patients, hypermethylation at hsa-miR-183 promoter significantly correlates with poor survival (log-rank test P = 0.03). DNA methylation analysis in healthy liver, benign liver tumors (hepatocellular adenoma and focal nodular hyperplasia) and their corresponding adjacent tissues showed absence of hypermethylation supporting the notion that aberrant methylation at hsa-miR-183 is specific for the malignant transformation of *** data indicate that hypermethylation of hsa-miR-183 is a frequent event in HCC and potentially useful as a novel surrogate diagnostic and prognostic marker.

关键词： hsa-miR-183 DNA methylation DNMT knockdown microRNA microarray