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Chinese Journal of Population,Resources and Environment 2005年第1期3卷 36-41页

作者： Lu Jiehua , Wang Hongbo 1 2.& Pan Yi 1 1. Institute of Population Research, Peking university, Beijing 100871, China 2. department of sociology,{2., los angeles, usa. Institute of Population Research Peking University Beijing 100871 China department of sociology University of California at Los Angeles Los Angeles United States

Based on the current literature, this paper is mainly intended to test whether environmental factors and socio-economic factors will have direct effect on the longevity at county level in China in order to determine the major determinants affecting local longevity level. Using the multi-regression model, we find the result that factors such as temperature, climate, longitude, type of soils, as well as type of agricultural food production play a major role in shaping the longevity at county level, and that socio- economic factors like infant mortality and gross death rate also have some direct impact on longevity, but the degree of impact is not as strong as the above environmental factors.

关键词： longevity socio-economic factors environmental factors

New concepts for generating interspecies chimeras using human pluripotent stem cells

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Protein & Cell 2022年第4期13卷 234-238页

作者： Alejandro De los angeles Jun Wu department of Psychiatry Yale University School of MedicineNew HavenCTUSA department of Molecular Biology University of Texas Southwestern Medical CenterDallasTXUSA Hamon Center for Regenerative Science and Medicine University of Texas Southwestern Medical CenterDallasTXUSA

The worldwide paucity of transplantable organs for patients is a devastating problem.While different approaches have been conceived to address this donor organ shortage,one strategy that has garnered significant attention recently is the prospect of producing human organs in animals through a technique called interspecies blastocyst complementation based on the generation of interspecies chimeras.Interspecies blastocyst complementation works by injecting pluripotent stem(PS)cells from one species into organogenesis-disabled blastocysts of another species(Kobayashi et al.,2.10).As the chimeric embryo develops,donor cells can fill the vacated developmental organ niche and enrich in a target organ of interest.In principle,interspecies blastocyst complementation may one day allow the generation of human organs inside animals.However,some ethical issues concerning research and potential human clinical use with chimeras persist(Hyun,2.19).

关键词： organs donor generating

A new oxidative pathway of nitric oxide production from oximes in plants

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Molecular Plant 2024年第1期17卷 178-198页

作者： Pedro Lopez-Gomez Javier Buezo Marina Urra Alfonso Cornejo Raquel Esteban Jorge Fernandez de los Reyes Estibaliz Urarte Estefania Rodriguez-Dobreva Alejandro Chamizo-Ampudia Alejandro Eguaras Sebastian Wolf Daniel Marino Victor Martinez-Merino Jose F.Moran Institute for Multidisciplinary Research in Applied Biology(IMAB) Department of SciencesPublic University of Navarre(UPNA)Avda.de Pamplona 12331192 MutilvaSpain Institute for Advanced Materials and Mathematics(INAMAT2. Department of SciencesPublic University of Navarre(UPNA)Campus de Arosadia31006 PamplonaSpain department of Plant Biology and Ecology University of the Basque Country(UPV/EHU)Sarriena s/nApdo.64448080 BilbaoSpain Center for Plant Molecular Biology(ZMBP) University of TubingenGeschwister-Scholl-Platz72074 TubingenGermany Institute of Natural Resources and Agrobiology of Salamanca(IRNASA) Department of Plant-Microorganism InteractionsSpanish National Research Council(CSIC)Cordel de Merinas40-5237008SalamancaSpain department of Biochemistry Area of Molecular BiologyVeterinary FacultyUniversity of LeonCampus de Vegazanas/n.24071 LeonSpain

Nitric oxide(NO)is an essential reactive oxygen species and a signal molecule in plants.Although several studies have proposed the occurrence of oxidative NO production,only reductive routes for NO production,such as the nitrate(NO_(3)^(-))-upper-reductase pathway,have been evidenced to date in land plants.However,plants grown axenically with ammonium as the sole source of nitrogen exhibit contents of nitrite and NO3−,evidencing the existence of a metabolic pathway for oxidative production of NO.We hypothesized that oximes,such as indole-3-acetaldoxime(IAOx),a precursor to indole-3-acetic acid,are intermediate oxidation products in NO synthesis.We detected the production of NO from IAOx and other oximes catalyzed by peroxidase(POD)enzyme using both 4-amino-5-methylamino-2.,7′-difluorescein fluorescence and chemiluminescence.Flavins stimulated the reaction,while superoxide dismutase inhibited it.Interestingly,mouse NO synthase can also use IAOx to produce NO at a lower rate than POD.We provided a full mechanism for POD-dependent NO production from IAOx consistent with the experimental data and supported by density functional theory calculations.We showed that the addition of IAOx to extracts from Medicago truncatula increased the in vitro production of NO,while in vivo supplementation of IAOx and other oximes increased the number of lateral roots,as shown for NO donors,and a more than 10-fold increase in IAOx dehydratase expression.Furthermore,we found that in vivo supplementation of IAOx increased NO production in Arabidopsis thaliana wild-type plants,while prx33-34 mutant plants,defective in POD33-34,had reduced production.Our data show that the release of NO by IAOx,as well as its auxinic effect,explain the superroot phenotype.Collectively,our study reveals that plants produce NO utilizing diverse molecules such as oximes,POD,and flavins,which are widely distributed in the plant kingdom,thus introducing a long-awaited oxidative pathway to NO production in plants.This knowledge has essential implications for und

关键词： ammonium oxidation auxin nitric oxide oxime peroxidase root phenotype

Posterior gut development in Drosophila:a model system for identifying genes controlling epithelial morphogenesis

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Cell Research 1998年第4期8卷 273-284页

作者： LENGYEL JUDITH A XUE JUN LIU (department of Molecular, Cell and Developmental Biology university of california at los angeles,{2., CA usa. 90095-1606 usa. department of Molecular Cell and Developmental Biology University of California at Los Angeles Los Angeles USA

The posterior gut of the Drosophila embryo, consisting of hindgut and Malpighian tubules, provides a simple,well-defined system where it is possible to use a genetic approach to define components essential for epithelial morphogenesis.We review here the advantages of Drosophila as a model genetic organism, the morphogenesis of the epithelial structures of the posterior gut, and what is known about the genetic requirements to form these structures.In overview, primordia are patterned by expression of hierarchies of transcription factors; this leads to localized expression of cell signaling molecules, and finally, to the least understood step: modulation of cell adhesion and cell shape. We describe approaches to identify additional genes that are required for morphogenesis of these simple epithelia, particularly those that might play a structural role by affecting cell adhesion and cell shape.

关键词： Organogenesis cell rearrangement convergent extension hindgut Malpighian tubule

Environmental Occurrence of Selenium in Waters and Related Health Significance

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Biomedical and Environmental Sciences 1997年第2期10卷 292-299页

作者： JANE L. VALENTINE(School of Public Health, university of california at los angeles, los angeles, CA 9002.,{2. School of Public Health University of California at Los Angeles 90024 USA.

Appreciable amounts of selenium in spring and well waters can be found due to geological occurrence. Concentrations of as much as 400 9000 μg/l have been reported in U. S. waters.These levels are 8 to 180 times the current EPA drinking water standard and approximate dietary exposures of 4900μg in selenosis regions of China. Reviews of health significance of the elevated drinking water exposures to U. S. populations revealed elevated concentrations of selenium in urine and blood. A decrease in glutathione peroxidase activity in such instances was noted. However noticeable symptoms and signs seem absent in studies reviewed. A comparison of intake levels (diet or drinking water) to urinary excretion for residents of China and the U. S. produced a correlation coefficient, r = 0. 82.(P < 0. 01 ) for the three research studies available

关键词： In Am Environmental Occurrence of Selenium in Waters and Related Health Significance

The Behavior of Solutions of Multidimensional Aggregation Equations with Mildly Singular Interaction Kernels

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Chinese Annals of Mathematics,Series B 2009年第5期30卷 463-482页

作者： Andrea L.BERTOZZI Thomas LAURENT department of Mathematics University of California-Los AngelesLos Angeles

The authors consider the multidimensional aggregation equation tρ-div(ρ▽K*ρ)=0 in which the radially symmetric attractive interaction kernel has a mild singularity at the origin (Lipschitz or better),and review recent results on this problem concerning well-posedness of nonnegative solutions and finite time blowup in multiple space dimensions depending on the behavior of the kernel at the origin.The problem with bounded initial data,data in Lp∩L1,and measure solutions are also considered.

关键词：奇异性相互作用行为方程聚集多维径向对称有限时间

OPTIMAL COARSE GRID SIZE IN DOMAIN DECOMPOSITION

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Journal of Computational Mathematics 1994年第4期12卷 291-297页

作者： Tony Chan Jian-Ping Shao(department of Mathematics, university of Califoruia,{2., usa. university of california 美国

In most domain decomposition (DD) methods, a coarse grid solve is employed to provide the global coupling required to produce an optimal method. The total cost of a method can depend sensitively on the choice of the coaxse grid size H. In this paper, we give a simple analysis of this phenomenon for a model elliptic problem and a variant of Smith's vertex space domain decomposition method [11, 3]. We derive the optimal value Hopt which asymptotically minimises the total cost of method (number of floating point operations in the sequential case and execution time in the parallel case), for subdomain solvers with different complekities. Using the value of Hopt, we derive the overall complexity of the DD method, which can be significantly lower than that of the subdomain solver

关键词： UCLA OPTIMAL COARSE GRID SIZE IN DOMAIN DECOMPOSITION CAM

FOUR STEP SCHEME FOR GENERAL MARKOVIAN FORWARD-BACKWARD SDES

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Journal of Systems Science & Complexity 2010年第3期23卷 546-571页

作者： Jin MA Jiongmin YONG Yanhong ZHAO department of Mathematics University of Southern California Los Angeles CA 90089 USA department of Mathematics University of Central Florida Orlando FL 32816 USA department of Mathematics Purdue University West Lafayette IN 47907 USA

This paper studies a class of forward-backward stochastic differential equations (FBSDE)in a general Markovian framework.The forward SDE represents a large class of strong Markov semimartingales,and the backward generator requires only mild regularity assumptions.The authors showthat the Four Step Scheme introduced by Ma,et al.(1994) is still effective in this case.Namely,the authors show that the adapted solution of the FBSDE exists and is unique over any prescribedtime duration;and the backward components can be determined explicitly by the forward componentvia the classical solution to a system of parabolic integro-partial differential equations.An importantconsequence the authors would like to draw from this fact is that,contrary to the general belief,in aMarkovian set-up the martingale representation theorem is no longer the reason for the well-posednessof the FBSDE,but rather a consequence of the existence of the solution of the decoupling integralpartialdifferential equation.Finally,the authors briefly discuss the possibility of reducing the regularityrequirements of the coefficients by using a scheme proposed by F.Delarue (2.02. to the current case.

关键词：正倒向随机微分方程 sdes 积分偏微分方程偏微分方程系统鞅表示定理解的存在性组成部分持续时间

TIME AND NORM OPTIMAL CONTROLS:A SURVEY OF RECENT RESULTS AND OPEN PROBLEMS

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Acta Mathematica Scientia 2011年第6期31卷 2203-2218页

作者： H. O. Fattorini department of Mathematics University of California Los Angeles

We present in this paper a survey of recent results on the relation between time and norm optimality for linear systems and the infinite dimensional version of Pontryagin＇s maximum principle. In particular, we discuss optimality （or nonoptimality） of singular controls satisfying the maximum principle and smoothness of the costate in function of smoothness of the target.

关键词： linear control systems in Banach spaces time optimal problem norm optimal problem

An Efficient Algorithm for Mobile Localization in Sensor Networks

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International Journal of Automation and computing 2012年第6期9卷 594-599页

作者： Xin-Min Xu 1 Yao Chen 1 Wen-Yao Xu 2.Fang Gong 2.1 department of Information Science and Electronic Engineering,Zhejiang university,Hangzhou 31002.,China 2.Electrical Engineering department,university of california,los angeles 90095,usa department of Information Science and Electronic Engineering Zhejiang University Hangzhou China Electrical Engineering department University of California Los Angeles USA

Node localization is a fundamental problem in wireless sensor network.There are many existing algorithms to estimate the locations of the nodes.However,most of the methods did not consider the presence of obstacles.In practice,obstacles will lead to blockage and reflection of communication signals between sensor nodes.Therefore,the presence of obstacles will greatly affect the localization result.In this paper,we implement an obstacle-handling algorithm based on the localization tool developed by MIT,The experimental result shows that the enhanced algorithm can reduce the average distance error by up to 46 %,compared to the original algorithm.

关键词： Wireless sensor network,automatic localization,intelligent computing,optimization,simulation.