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Search Results: 1 - 10 of 58995 matches for " RuiFeng Yang "
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Research on Tendency and Behavior of the New Generation Employees Turnover  [PDF]
Ruifeng Yang
Journal of Human Resource and Sustainability Studies (JHRSS) , 2016, DOI: 10.4236/jhrss.2016.44031
Abstract: In recent years, a large number of new generation employees entered the enterprise and gradually became the mainstay of enterprises, but the turnover rate is high and it brought heavy pressure and burdens to employers. Therefore, considerable importance has been attached to the research on the behavior of the new generation employees by the academic researchers and business managers. Unfortunately, so far, there is little theoretical research on the behavior of the new generation employees from the perspective of talent environment. This paper makes a theoretical review of the environmental factors that affect the turnover behavior of new generation employees and then designs an effective intervention mechanism to reduce the turnover rate of new generation employees and provides the reference for the enterprise managers to make policies of keeping employees.
Existence of Optical Vortices
Yisong Yang,Ruifeng Zhang
Physics , 2012,
Abstract: Optical vortices arise as phase singularities of the light fields and are of central interest in modern optical physics. In this paper, some existence theorems are established for stationary vortex wave solutions of a general class of nonlinear Schr\"{o}dinger equations. There are two types of results. The first type concerns the existence of positive-radial-profile solutions which are obtained through a constrained minimization approach. The second type addresses the existence of saddle-point solutions through a mountain-pass-theorem or min-max method so that the wave propagation constant may be arbitrarily prescribed in an open interval. Furthermore some explicit estimates for the lower bound and sign of the wave propagation constant with respect to the light beam power and vortex winding number are also derived for the first type solutions.
Angle structures and hyperbolic $3$-manifolds with totally geodesic boundary
Faze Zhang,Ruifeng Qiu,Tian Yang
Mathematics , 2014,
Abstract: This notes explores angle structures on ideally triangulated compact $3$-manifolds with high genus boundary. We show that the existence of angle structures implies the existence of a hyperbolic metric with totally geodesic boundary, and conversely each hyperbolic $3$-manifold with totally geodesic boundary has an ideal triangulation that admits angle structures.
Dynamics of Electrostatic MEMS Actuators
Yisong Yang,Ruifeng Zhang,Le Zhao
Mathematics , 2012,
Abstract: Electrostatic actuators are simple but important switching devices for MEMS applications. Due to the difficulties associated with the electrostatic nonlinearity, precise mathematical description is often hard to obtain for the dynamics of these actuators. Here we present two sharp theorems concerning the dynamics of an undamped electrostatic actuator with one-degree of freedom, subject to linear and nonlinear elastic forces, respectively. We prove that both situations are characterized by the onset of one-stagnation-point periodic response below a well-defined pull-in voltage and a finite-time touch-down or collapse of the actuator above this pull-in voltage. In the linear-force situation, the stagnation level, pull-in voltage, and pull-in coordinate of the movable electrode may all be determined explicitly, following the recent work of Leus and Elata based on numerics. Furthermore, in the nonlinear-force situation, the stagnation level, pull-in voltage, and pull-in coordinate may be described completely in terms of the electrostatic and mechanical parameters of the model so that they approach those in the linear-force situation monotonically in the zero nonlinear-force limit.
Stabilizations of Reducible Heegaard Splittings
Ruifeng Qiu
Mathematics , 2004,
Abstract: C. Gordon conjectured that a connected sum of two Heegaard splittings is stabilized if and only if one of the two factors is stabilized (Problem 3.91 in Kirby's problem list). In this paper, we shall prove this conjecture.
INVERSE ANALYSIS OF PSEUDO STATIC DISPLACEMENT FOR INHOMOGENEOUS VISCOELASTIC MEDIA
非均质粘弹性介质的准静态位移反演

Yang Haitian,Wu Ruifeng,
张群
,杨海天,邬瑞锋

力学学报 , 1996,
Abstract: Based on the finite element and optimization methods, this paper develops the formulae of inverse analysis for inhomogeneous viscoelastic media. A preliminary discussion about identification of viscoelastic constitutive models is made, the effect of information error is considered, and some numerical examples are exhibited.
Characterization and Expression Analysis of a Fiber Differentially Expressed Fasciclin-like Arabinogalactan Protein Gene in Sea Island Cotton Fibers
Hengwei Liu, Ruifeng Shi, Xingfen Wang, Yuxin Pan, Zhikun Li, Xinlei Yang, Guiyin Zhang, Zhiying Ma
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070185
Abstract: Fasciclin-like arabinogalactan (FLA) protein is a cell-wall-associated protein playing crucial roles in regulating plant growth and development, and it was characterized in different plants including Upland cotton (Gossypium hirsutum L.). In cDNA-AFLP analysis of 25 DPA (days post anthesis) fiber mRNA, two FLA gene-related transcripts exhibit differential expression between Sea Island cotton (G. barbadense L.) and Upland cotton. Based on the transcript-derived fragment, RACE-PCR and realtime PCR technique, GbFLA5 full-length cDNA was isolated and its expression profiles were characterized in both cotton plant tissues and secondary cell wall (SCW) fibers in this study. The 1154 bp GbFLA5 cDNA contains an ORF of 720 bp, encoding GbFLA5 protein of 239 amino acids residues in length with an estimated molecular mass of 25.41 kDa and isoelectric point of 8.63. The deduced GbFLA5 protein contains an N-terminal signal sequence, two AGP-like domains, a single fasciclin-like domain, and a GPI anchor signal sequence. Phylogenetic analysis shows that GbFLA5 protein is homologous to some known SCW-specific expressed FLAs of plant developing xylem, tension wood and cotton fibers. In the SCW deposition stage from 15 to 45 DPA detected, FLA5 maintains a significantly higher expression level in Sea Island cotton fibers than in Upland cotton fibers. The increasing FLA5 transcript abundance coincided with the SCW deposition process and the expression intensity differences coincided with their fiber strength differences between Sea Island cotton and Upland cotton. These expression profile features of GbFLA5 in cotton fibers revealed its tissue-specific and SCW developmental stage-specific expression characters. Further analysis suggested that GbFLA5 is a crucial SCW-specific protein which may contribute to fiber strength by affecting cellulose synthesis and microfibril deposition orientation.
Simvastatin Blocks Blood-Brain Barrier Disruptions Induced by Elevated Cholesterol Both In Vivo and In Vitro
Xijuan Jiang,Maojuan Guo,Jinling Su,Bin Lu,Dongming Ma,Ruifeng Zhang,Lin Yang,Qiang Wang,Yiwen Ma,Yingchang Fan
International Journal of Alzheimer's Disease , 2012, DOI: 10.1155/2012/109324
Abstract: Background. Hypercholesterolemia and disruptions of the blood brain barrier (BBB) have been implicated as underlying mechanisms in the pathogenesis of Alzheimer's disease (AD). Simvastatin therapy may be of benefit in treating AD; however, its mechanism has not been yet fully understood. Objective. To explore whether simvastatin could block disruption of BBB induced by cholesterol both in vivo and in vitro. Methods. New Zealand rabbits were fed cholesterol-enriched diet with or without simvastatin. Total cholesterol of serum and brain was measured. BBB dysfunction was evaluated. To further test the results in vivo, rat brain microvascular endothelial cells (RBMECs) were stimulated with cholesterol in the presence/absence of simvastatin in vitro. BBB disruption was evaluated. Results. Simvastatin blocked cholesterol-rich diet induced leakage of Evan's blue dye. Cholesterol content in the serum was affected by simvastatin, but not brain cholesterol. Simvastatin blocked high-cholesterol medium-induced decrease in TEER and increase in transendothelial FITC-labeled BSA Passage in RBMECs. Conclusions. The present study firstly shows that simvastatin improves disturbed BBB function both in vivo and in vitro. Our data provide that simvastatin may be useful for attenuating disturbed BBB mediated by hypercholesterolemia. 1. Introduction The blood-brain barrier (BBB), a barrier between the central nervous system (CNS) and the systemic circulation, maintains homeostasis within the brain microenvironment. The anatomical substrate of the BBB is the cerebral microvascular endothelium, which, together with astrocytes, pericytes, neurons, and the extracellular matrix, constitutes a “neurovascular unit” that is essential for the health and function of the CNS. Failure of the BBB is a critical event in the progression of several diseases, such as Alzheimer’s disease (AD) [1–4]. BBB breakdown is accompanied by an increase in the trans-endothelial permeability to substances, which can damage the microenvironment of the brain and affect the structure and function of the CNS. Therefore, it is not surprising that strategies have been developed to “repair” the BBB in order to restore normal brain homeostasis and prevent the infiltration of pharmacologically active (noxious) substances into the brain. Cholesterol is one of the most notorious natural risk factors for arteriosclerotic cerebrovascular disease [5, 6]. Mounting evidence suggests that cholesterol also plays a critical role in the early stage of AD [7–9]. Hypercholesterolemia leads to increased BBB leakage, an effect
Second-site suppressors of HIV-1 capsid mutations: restoration of intracellular activities without correction of intrinsic capsid stability defects
Ruifeng Yang, Jiong Shi, In-Ja L Byeon, Jinwoo Ahn, Jonathan H Sheehan, Jens Meiler, Angela M Gronenborn, Christopher Aiken
Retrovirology , 2012, DOI: 10.1186/1742-4690-9-30
Abstract: To further examine the connection between HIV-1 capsid stability and infectivity, we isolated second-site suppressors of HIV-1 mutants exhibiting unstable (P38A) or hyperstable (E45A) capsids. We identified the respective suppressor mutations, T216I and R132T, which restored virus replication in a human T cell line and markedly enhanced the fitness of the original mutants as revealed in single-cycle infection assays. Analysis of the corresponding purified N-terminal domain CA proteins by NMR spectroscopy demonstrated that the E45A and R132T mutations induced structural changes that are localized to the regions of the mutations, while the P38A mutation resulted in changes extending to neighboring regions in space. Unexpectedly, neither suppressor mutation corrected the intrinsic viral capsid stability defect associated with the respective original mutation. Nonetheless, the R132T mutation rescued the selective infectivity impairment exhibited by the E45A mutant in aphidicolin-arrested cells, and the double mutant regained sensitivity to the small molecule inhibitor PF74. The T216I mutation rescued the impaired ability of the P38A mutant virus to abrogate restriction by TRIMCyp and TRIM5α.The second-site suppressor mutations in CA that we have identified rescue virus infection without correcting the intrinsic capsid stability defects associated with the P38A and E45A mutations. The suppressors also restored wild type virus function in several cell-based assays. We propose that while proper HIV-1 uncoating in target cells is dependent on the intrinsic stability of the viral capsid, the effects of stability-altering mutations can be mitigated by additional mutations that affect interactions with host factors in target cells or the consequences of these interactions. The ability of mutations at other CA surfaces to compensate for effects at the NTD-NTD interface further indicates that uncoating in target cells is controlled by multiple intersubunit interfaces in the vira
SIRT1 suppresses PMA and ionomycin-induced ICAM-1 expression in endothelial cells
YuYan Jia,Peng Gao,HouZao Chen,YanZhen Wan,Ran Zhang,ZhuQin Zhang,RuiFeng Yang,Xu Wang,Jing Xu,DePei Liu
Science China Life Sciences , 2013, DOI: 10.1007/s11427-012-4407-7
Abstract: Intercellular adhesion molecule-1 (ICAM-1) plays an important role in the recruitment of leukocytes to the endothelium, which causes inflammation and initiation of atherosclerosis. We have previously shown that endothelium-specific over-expression of class III deacetylase SIRT1 decreases atherosclerosis. We therefore addressed the hypothesis that SIRT1 suppresses ICAM-1 expression in the endothelial cells. Here, we found that expression of SIRT1 and ICAM-1 was significantly induced by PMA and ionomycin (PMA/Io) in human umbilical vein endothelial cells (HUVECs). Adenovirus-mediated over-expression of SIRT1 significantly inhibited PMA/Io-induced ICAM-1 expression in HUVECs. Knockdown of SIRT1 by RNA interference (RNAi) resulted in increased expression of ICAM-1 in HUVECs. Luciferase report assay showed that over-expression of SIRT1 suppressed ICAM-1 promoter activity both in basic and in PMA/Io-induced conditions. We further found that SIRT1 was involved in transcription complex binding on the ICAM-1 promoter by chromatin immunoprecipitation (ChIP) assays. Furthermore, SIRT1 RNAi increased NF-κB p65 binding ability to the ICAM-1 promoter by ChIP assays. Overall, these data suggests that SIRT1 inhibits ICAM-1 expression in endothelial cells, which may contribute to its anti-atherosclerosis effect.
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