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Communications in Computational Physics 2008年第3期3卷 734-758页

作者： Anne Gelb Rodrigo B.Platte w.steven Rosenthal Department of Mathematics and Statistics Arizona State UniversityTempeArizona 85287USA

we investigate numerical approximations based on polynomials that are orthogonal with respect to a weighted discrete inner product and develop an algorithm for solving time dependent differential *** focus on the family of super Gaussian weight functions and derive a criterion for the choice of parameters that provides good accuracy and stability for the time evolution of partial differential *** results show that this approach circumvents the problems related to the Runge phenomenon on equally spaced nodes and provides high accuracy in *** time stability,small corrections near the ends of the interval are computed using local polynomial *** numerical experiments illustrate the performance of the method.

关键词： Discrete least-squares orthogonal polynomials spectralmethods high order numerical methods uniform grid.

Cyber Attack Protection and Control of Microgrids

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IEEE/CAA Journal of Automatica Sinica 2018年第2期5卷 602-609页

作者： Md Masud Rana Li Li steven w.Su Faculty of Engineering and Information Tech- nology University of Technology Sydney Broadway NSW 2007 Australia

Recently, the smart grid has been considered as a next-generation power system to modernize the traditional grid to improve its security, connectivity, efficiency and ***, the smart grid is susceptible to malicious cyber attacks, which can create serious technical, economical, social and control problems in power network operations. In contrast to the traditional cyber attack minimization techniques, this paper proposes a recursive systematic convolutional(RSC) code and Kalman filter(KF) based method in the context of smart ***, the proposed RSC code is used to add redundancy in the microgrid states, and the log maximum a-posterior is used to recover the state information, which is affected by random noises and cyber attacks. Once the estimated states are obtained by KF algorithm, a semidefinite programming based optimal feedback controller is proposed to regulate the system states, so that the power system can operate properly. Test results show that the proposed approach can accurately mitigate the cyber attacks and properly estimate and control the system states.

关键词： Index Terms--Cyber attack Kalman filter (KF) optimal feed-back control renewable microgrid smart grid.

Non-genetic contributions of the sperm nucleus to embryonic development

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Asian Journal of Andrology 2011年第1期13卷 31-35页

作者： Yasuhiro Yamauchi Jeffrey A Shaman w.steven w.rd Department Anatomy and Reproductive Biology Institute for Biogenesis Research John A. Burns School of Medicine University of Hawaii at Manoa Honolulu HI USA GLP Services GENEWlZ Inc. 115 Corporate Blvd. South Plainfield NJ 07080 USA

Recent data from several laboratories have provided evidence that the newly fertilized oocyte inherits epigenetic signals from the sperm chromatin that are required for proper embryonic development. For the purposes of this review, the term epigenetic is used to describe all types of molecular information that are transmitted from the sperm cell to the embryo. There are at least six different forms of epigenetic information that have already been established as being required for proper embryogenesis in mammals or for which there is evidence that it may do so. These are （i） DNA methylation; （ii） sperm-specific histones, （iii） other chromatin-associated proteins; （iv） the perinuclear theca proteins; （v） sperm-born RNAs and, the focus of this review; and （vi） the DNA loop domain organization by the sperm nuclear matrix. These epigenetic signals should he considered when designing protocols for the manipulation and cryopreservation of spermatozoa for assisted reproductive technology as necessary components for effective fertilization and subsequent embryo development.

关键词： embryogenesis epigenetics sperm DNA sperm nuclear matrix DNA loop domain organization

Biotin biosynthesis in Mycobacterium tuberculosis: physiology, biochemistry and molecular intervention

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Protein & Cell 2011年第9期2卷 691-695页

作者： wanisa Salaemae Al Azhar Grant w.Booker steven w.Polyak School of Molecular and Biomedical Sciences University of AdelaideSouth Australia 5005Australia

Biotin is an important micronutrient that serves as an essential enzyme *** obtain biotin either through de novo synthesis or by active uptake from exogenous *** are unusual amongst bacteria in that their primary source of biotin is through de novo *** we review the importance of biotin biosynthesis in the lifecycle of *** screens designed to identify key metabolic processes have highlighted a role for the biotin biosynthesis in bacilli growth,infection and survival during the latency *** studies help to establish the biotin biosynthetic pathway as a potential drug target for new anti-tuberculosis agents.

关键词： synthesis. phase. synthesis

Myxomycetes associated with grasslands of the western central United States

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Fungal Diversity 2013年第2期59卷 147-158页

作者： Adam w.Rollins steven L.Stephenson Department of Biology Lincoln Memorial UniversityHarrogateTN 37752USA Department of Biological Sciences University of ArkansasFayettevilleAR 72701USA

The assemblages of myxomycetes associated with the three types of temperate grasslands(tall grass,mixed grass and short grass)found across the western central United States were examined by collecting samples for isolation of these organisms from nine study *** consisted of two types of ground litter,two types of aerial litter(dead but still attached plant parts)and *** were brought back to the laboratory and used to prepare a series of moist chamber *** cultures yielded 1,301 collections of myxomycetes representing 59 species in 18 *** collections could be identified only to genus and one in particular(Lepidoderma sp.)appears to be an undescribed *** spectabile was recorded for the first time in North ***,only eight species(Badhamia melanospora,Didymium anellus,***,***,Perichaena depressa,Physarum cinereum,***,and Stemonitis fusca)were recovered from all nine study sites and thus are considered to represent a core component of the myxomycete biota of temperate grasslands.

关键词： Community ecology Ecological distribution Grasslands Microhabitat Myxogastrids

Response of Microcystis aeruginosa FACHB-905 to different nutrient ratios and changes in phosphorus chemistry

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Journal of Oceanology and Limnology 2018年第4期36卷 1040-1052页

作者： PENG Guotao steven w.wILHELM LIN Sijie wANG Xlangrong College of Environmental Science and Engineering State Key Laboratory of Pollution Control and Resource ReuseTongj UniversityShanghai 200092China Department of Environmental Science and Engineering Fudan UniversityShanghai 200433China Department of Microbiology University of TennesseeKnoxvilleTN37920USA

Cyanobacterial blooms are a global problem, with their occurrence tightly tied to nutrient loading. we cultured Microcystis aeruginosa FACHB-905 in growth medium with either inorganic(orthophosphate) or organic(β-glycerophosphate or polyphosphate) phosphorus and at different N:P ratios with 50:1, 30:1, 16:1, 4:1 and 1:4, serving as the phosphorus source. Fluorescence parameters were measured to determine the response of cellular responses to nutrient stress. Scanning electron microscopy(SEM) and estimates of antioxidant activity were employed to examine potential mechanisms of physical change. The results demonstrate that inorganic phosphorus was more bioavailable to M. aeruginosa relative to organic phosphorus in culture. The highest cell concentration(2.21×10~6 cells/mL), chlorophyll-a(0.39 pg/cell) and phycocyanin(1.57 pg/cell) quotas and high levels of chlorophyll fluorescence parameters( rETR, E_k, α, φ_(PSⅡ) and F_v/F_m) were obtained when phosphorus was supplied as K_2 HPO_4 at a N:P ratio of 16–30. Organic sources of phosphorus(β-glycerophosphate and polyphosphate) were bioavailable to M. aeruginosa. In addition, too concentrated orthophosphate(N:P=1:4) resulted in the oxidative stress and lipid peroxidation of cell membrane(identified by the antioxidant system activity), and the photosynthetic activity declined consequently. This study has demonstrated the effects of different phosphorus chemistries and N:P ratios on the cyanobacterial growth, photosynthetic activity and cell physiology, which could be an effective tool for predicting cyanobacterial dominance or N-deficiency in natural lakes(due to the superior ability of cyanobacteria for dissolved N and fix atmospheric N in some cases).

关键词： antioxidant system chlorophyll fluorescence parameters Microcystis nutrient stress photosynthesis

Unmasking the responses of the stem cells and progenitors in the subventricular zone after neonatal and pediatric brain injuries

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Neural Regeneration Research 2016年第1期11卷 45-48页

作者： Mariano Guardia Clausi Ekta Kumari steven w.Levison Department of Pharmacology Physiology and Neuroscience Rutgers-New Jersey Medical School

There is great interest in the regenerative potential of the neural stem cells and progenitors that populate the subventricular zone（SVZ）. However, a comprehensive understanding of SVZ cell responses to brain injuries has been hindered by the lack of sensitive approaches to study the cellular composition of this niche. Here we review progress being made in deciphering the cells of the SVZ gleaned from the use of a recently designed flow cytometry panel that allows SVZ cells to be parsed into multiple subsets of progenitors as well as putative stem cells. we review how this approach has begun to unmask both the heterogeneity of SVZ cells as well as the dynamic shifts in cell populations with neonatal and pediatric brain injuries. we also discuss how flow cytometric analyses also have begun to reveal how specific cytokines, such as Leukemia inhibitory factor are coordinating SVZ responses to injury.

关键词： CNS regeneration cytokines glial progenitors gliogenesis inflammation cerebral palsy traumatic brain injury stroke

A model for the control of DNA integrity by the sperm nuclear matrix

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Asian Journal of Andrology 2015年第4期17卷 610-615页

作者： Joanna E Gawecka Jordi Ribas-Maynou Jordi Benet w.steven w.rd Clinical and Translational Research Program Universityof Hawaii Cancer Center Honolulu HI USA Cell BiologyUnit Cell Biology Phisiology and Immunology DepartmentMedicine Faculty Universitat Autonoma de Barcelona08193 Bellaterra Spain Center of Male Infertility andAnalysis de Barcelona Edifici Eureka PBM5 Parc deRecerca de la UAB Campus de la UAB 08193 BellaterraSpain Institute for Biogenesis Research Departmentof Anatomy Biochemistry and Physiology Honolulu HIUSA Department of Obstetrics Gynecology and Women'sHealth John A. Burns School of Medicine University ofHawaii at Manoa. Honolulu. HI 96822. USA.

The highly condensed chromatin of mammalian spermatozoa is usually considered to be biologically inert before fertilization. However, we have demonstrated that even in this compacted state, sperm chromatin is subject to degradation at open configurations associated with the nuclear matrix through a process we have termed sperm chromatin fragmentation （SCF）. ＂[his suggests that a mechanism exists to monitor the health of spermatozoa during transit through the male reproductive tract and to destroy the genome of defective sperm cells. The site of DNA damage in SCF, the matrix attachment sites, are the same that we hypothesize initiate DNA synthesis in the zygote. when sperm that have damaged DNA are injected into the oocyte, the newly created zygote responds by delaying DNA synthesis in the male pronudeus and, if the damage is severe enough, arresting the embryo＇s development. Here we present a model for paternal DNA regulation by the nuclear matrix that begins during sperm maturation and continues through early embryonic development.

关键词： DNA mammalian spermatozoa

Nanoindentation in elastoplastic materials:insights from numerical simulations

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International Journal of Smart and Nano Materials 2010年第2期1卷 95-114页

作者： steven w.Moore Majid T.Manzari Yin-Lin Shen Department of Mechanical and Aerospace Engineering The George Washington UniversityWashingtonDC 20052USA Department of Civil and Environmental Engineering The George Washington UniversityWashingtonDC 20052USA

Finite element simulations of nanoindentation were performed on an elastoplastic material using Berkovich and conical indenters to investigate the effects of geometry on the load-displacement response of the *** Berkovich indenter,widely used in nanoindentation experiments,is typically simplified to a theoretically equivalent 70.3°conical indenter for numerical simulations,which allows for a less computationally intensive two-dimensional(2D)axisymmetric *** studies into the validity of this equivalence assumption for indentations in elastoplastic materials have varying *** 2D and 3D finite element simulations,the present study investigates the response of elastoplastic materials,obeying a combined isotropic and kinematic hardening,to indentation with conical and Berkovich *** show that there is a clear difference in the load-displacement response of the selected material to the two *** Berkovich geometry is found to produce a more localized pattern of contact stresses and plastic strains,leading to a smaller mobilized force for the same magnitude of *** further validate the numerical simulations,experimental results of nanoindentation into an aluminium specimen were compared to elastoplastic finite element simulation *** suggest that machining-induced residual stresses have likely affected the experimental results.

关键词： nanoindentation finite element analysis elastoplasticity tip geometry

McGraw-Hill`s GRE :Graduate Record Examination general test / 2010 ed.

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McGraw-Hill`s GRE :Graduate Record Examination general test ...