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Search Results: 1 - 10 of 28240 matches for " Xuejing Zhu "
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Regularized 3D functional regression for brain image data via Haar wavelets
Xuejing Wang,Bin Nan,Ji Zhu,Robert Koeppe
Statistics , 2014, DOI: 10.1214/14-AOAS736
Abstract: The primary motivation and application in this article come from brain imaging studies on cognitive impairment in elderly subjects with brain disorders. We propose a regularized Haar wavelet-based approach for the analysis of three-dimensional brain image data in the framework of functional data analysis, which automatically takes into account the spatial information among neighboring voxels. We conduct extensive simulation studies to evaluate the prediction performance of the proposed approach and its ability to identify related regions to the outcome of interest, with the underlying assumption that only few relatively small subregions are truly predictive of the outcome of interest. We then apply the proposed approach to searching for brain subregions that are associated with cognition using PET images of patients with Alzheimer's disease, patients with mild cognitive impairment and normal controls.
Urinary TWEAK Level as a Marker of Lupus Nephritis Activity in 46 Cases
Zhu Xuejing,Tan Jiazhen,Li Jun,Xu Xiangqing,Yuan Shuguang,Liu Fuyou
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/359647
Abstract: Objective. This study is designed to observe the urinary tumor necrosis factor-like weak inducer of apoptosis (TWEAK) levels in patients with lupus nephritis (LN) and to identify new biomarker of lupus nephritis activity. Methods. Study subjects were 46 cases of patients with LN (including 34 of active cases) who underwent routine renal biopsy. Activity and chronicity indexes of LN were assessed using pathological criteria proposed by Hill et al. in 2000. Urinary TWEAK (uTWEAK) level and Monocyte chemoattractant protein-1 (MCP-1) level were detected by ELISA. Results. Urinary TWEAK level was significantly higher in active LN group than in non-active LN group. Correlation analysis showed that urinary TWEAK levels were significantly correlated with activity index (=0.825, <0.01), glomerular activity index (=0.754, <0.01), and tubulointerstitial qualitative activity index (=0.751, <0.01), while not significant correlated with chronicity Index (>0.05). The association between urinary TWEAK levels and urinary MCP-1 levels were significant in active LN group (=0.809, <0.01) but not significant in non-active LN group (>0.05). Conclusions. uWEAK levels were correlated with all active indexes of LN, suggesting its potential role as novel biomarker of active lupus nephritis.
Hexachlorophene Is a Potent KCNQ1/KCNE1 Potassium Channel Activator Which Rescues LQTs Mutants
Yueming Zheng, Xuejing Zhu, Pingzheng Zhou, Xi Lan, Haiyan Xu, Min Li, Zhaobing Gao
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051820
Abstract: The voltage-gated KCNQ1 potassium channel is expressed in cardiac tissues, and coassembly of KCNQ1 with an auxiliary KCNE1 subunit mediates a slowly activating current that accelerates the repolarization of action potential in cardiomyocytes. Mutations of KCNQ1 genes that result in reduction or loss of channel activity cause prolongation of repolarization during action potential, thereby causing long QT syndrome (LQTs). Small molecule activators of KCNQ1/KCNE1 are useful both for understanding the mechanism of the complex activity and for developing therapeutics for LQTs. In this study we report that hexachlorophene (HCP), the active component of the topical anti-infective prescription drug pHisoHex, is a KCNQ1/KCNE1 activator. HCP potently increases the current amplitude of KCNQ1/KCNE1 expressed by stabilizing the channel in an open state with an EC50 of 4.61±1.29 μM. Further studies in cardiomyocytes showed that HCP significantly shortens the action potential duration at 1 μM. In addition, HCP is capable of rescuing the loss of function of the LQTs mutants caused by either impaired activation gating or phosphatidylinositol-4,5-bisphosphate (PIP2) binding affinity. Our results indicate HCP is a novel KCNQ1/KCNE1 activator and may be a useful tool compound for the development of LQTs therapeutics.
Monolithic Integration of MQW DFB Laser and EA Modulator in 1.55μm Wavelength
Yan Xuejing,Xu Guoyang,Zhu Hongliang,Zhou Fan,Wang Xiaojie,Zhang Jingyuan,Tian Huiliang,Ma Chaohu,Shu Huiyun,Bai Y
半导体学报 , 1999,
Abstract: MultipleQuantumWel(MQW)Electroabsorption(EA)modulatorintegratedwithDistributedFeedback(DFB)laserisfulofpromisefo...
利用北斗系统构建LEO-R海洋遥感星座的理论研究
Constructing LEO-R Ocean Remote Sensing Constellation Using BeiDou System

高超群, 杨东凯, 裘雪敬, 朱云龙
GAO Chaoqun
, YANG Dongkai, QIU Xuejing, ZHU Yunlong

- , 2018, DOI: 10.13203/j.whugis20160440
Abstract: 北斗是中国独立研发的导航系统,其反射事件的数量和分布规律有特殊的优势,也是设计低轨道反射信号(low earth orbit-reflection,LEO-R)星座的重要指标。利用具有均匀性和稳定性优势的Walker架构,设计了LEO-R星座,实现基于北斗反射信号的全球海洋遥感探测。分析星座与北斗的几何关系,推导了北斗反射事件被覆盖的判断条件。提出了标记-遍历的镜点计算方法,定量分析星座参数对北斗反射事件数量和分布规律的影响,并模拟36 h的尼伯特台风场景作为探测对象。结果表明,星座的覆盖时间百分比为97.619 73%,最大重访时间为404.511 s,验证了该星座全球遥感探测的有效性
Taylor expansions and Castell estimates for solutions of stochastic differential equations driven by rough paths
Qi Feng,Xuejing Zhang
Mathematics , 2012,
Abstract: We study the Taylor expansion for the solution of a differential equation driven by $p$-rough paths with $p>2$. We will prove a general theorem concerning the convergence of the Taylor expansion on a nonempty interval provided that the vector fields are analytic on a ball centered at the initial point. We will also derive criteria that enable us to study the rate of convergence of the Taylor expansion. Our deterministic results can be applied to stochastic differential equations driven by fractional Brownian motions with Hurst parameter $1/4 < H < 1/2$ and continuous Gaussian process with finite $2D$ $\rho-$variation. At last, which is also the main and the most original part of this paper, we give an Castell expansion and a tail estimate with exponential decay for the remainder terms of the solutions of the differential equations driven by continuous centered Gaussian process with finite $2D \rho-$variation and fractional Brownian motion with Hurst parameter $H>1/4$.
Taylor expansion for the solution of a stochastic differential equation driven by fractional Brownian motions
Fabrice Baudoin,Xuejing Zhang
Mathematics , 2011,
Abstract: We study the Taylor expansion for the solution of a di?erential equation driven by a multidimensional Holder path with exponent \beta> 1/2. We derive a convergence criterion that enables us to write the solution as an infinite sum of iterated integrals on a nonempty interval. We apply our deterministic results to stochastic di?erential equations driven by fractional Brownian motions with Hurst parameter H > 1\2. We also prove that by using L_2 estimates of iterated integrals, the criterion and the speed of convergence for the stochastic Taylor expansion can be improved using Borel-Cantelli type arguments when H\in (1/2, 3/4).
Dynamics of the generalized 3x + 1 function determined by its fractal images

Xingyuan Wang,Xuejing Yu,

自然科学进展 , 2008,
Abstract: Two different complex maps were obtained by generalizing 3x+1 function to the complex plane, and fractal images for this two complex maps were constructed by using escape time, stopping time and total stopping time arithmetic. The dynamics of the generalized 3x+1 function based on the structural characteristics of the fractal images was studied. We found that: (1) The size and structure of the stable regions, stopping regions, total stopping regions, and divergent regions for the three types of fractal images depend on convergence rate of the map on the x and y axes. (2) The black stable regions constructed respectively by escape time and total stopping time are almost overlapped, demonstrating that 3x + 1 function converged steadily. (3) All of the three fractal images are symmetric to the real axis. The structures on the neighborhood of positive integer number are symmetric to a perpendicular line, which is corresponding to the point or its nearby points on the x axis. And the structures have complicated fractal structure characteristics. These findings indicate that the generalized 3x + 1 function on integer number and its neighborhood contains plentiful information in the complex plane.
M型磷脂酶A2受体及其抗体在乙肝病毒#br# 相关性膜性肾病中的临床意义
Role of M-type phospholipase A2 receptor and its antibody in hepatitis B virus-associated membranous nephropathy

许向青,朱雪婧,袁曙光,姜文玲,夏运成,刘虹,李军,孙林,彭佑铭,刘伏友,
XU Xiangqing
, ZHU Xuejing, YUAN Shuguang, JIANG Wenling

- , 2016, DOI: 10.11817/j.issn.1672-7347.2016.10.009
Abstract: 目的:研究M型磷脂酶A2受体(phospholipase A2 receptor,PLA2R)在乙肝病毒相关性膜性肾病(hepatitis B virus-associated membranous nephropathy,HBV-MN)患者血液及肾组织中的表达情况,并探讨肾组织PLA2R阳性表达在乙型肝炎相关性肾小球肾炎(hepatitis B virus associated glomerulone nephritis,HBV-GN)患者中的临床和病理特点。 方法: 选取经肾活检确诊的49例HBV-MN患者。检测血清抗PLA2R抗体以及肾组织PLA2R的表达,将患者分为肾组织PLA2R表达阳性组和阴性组,比较两组间临床指标、病理改变、血抗PLA2R抗体表达水平的差异。结果:17例患者存在肾组织PLA2R阳性表达,其中10例患者血清抗PLA2R抗体阳性。肾组织阳性组较阴性组24 h尿蛋白水平升高,血白蛋白水平下降,血清HbsAg阳性比例更高(70.5%),肾组织HbsAg表达比例更高(71%)。结论:肾组织PLA2R以及血清抗PLA2R抗体在HBV-MN患者中有一定表达,其表达可能与HBV-MN患者血清以及肾组织中HbsAg沉积有关。肾组织PLA2R阳性患者肾小球慢性损伤可能相对更重
General Decay Stability for Stochastic Functional Differential Equations with Infinite Delay
Yue Liu,Xuejing Meng,Fuke Wu
International Journal of Stochastic Analysis , 2010, DOI: 10.1155/2010/875908
Abstract: So far there are not many results on the stability for stochastic functional differential equations with infinite delay. The main aim of this paper is to establish some new criteria on the stability with general decay rate for stochastic functional differential equations with infinite delay. To illustrate the applications of our theories clearly, this paper also examines a scalar infinite delay stochastic functional differential equations with polynomial coefficients. 1. Introduction Stability is one of the central problems for both deterministic and stochastic dynamic systems. Due to introduction of stochastic factors, stochastic stability mainly includes almost sure stability and the moment stability. In a series of papers (see [1–5]), Mao et al. examined the moment exponential stability and almost sure exponential stability for various stochastic systems. In many cases we may find that the Lyapunov exponent equals zero, namely, the equation is not exponentially stable, but the solution does tend to zero asymptotically. By this phenomenon, Mao [6] considered polynomial stability of stochastic system, which shows that solution tends to zero polynomially. Then in [7], he extended these two classes of stability into the general decay stability. In general, time delay and system uncertainty are commonly encountered and are often the source of instability (see [8]). Many studies focused on stochastic systems with delay. Especially, infinite delay systems have received the increasing attention in the recent years since they play important roles in many applied fields (cf. [7, 9–13]). Under the Lipschitz condition and the linear growth condition, Wei and Wang [14] built the existence-and-uniqueness theorem of global solutions to stochastic functional differential equations with infinite delay. There is also some other literature to consider stochastic functional differential equations with infinite delay and we here only mention [15–17]. However, to the best knowledge of the authors, there are not many results on the stability with general decay rate for stochastic functional equations with infinite delay. It is therefore interesting to consider the stability of infinite delay stochastic systems. The main aim of this paper is to establish some new criteria for th moment stability and almost surely asymptotic stability with general decay rate of the global solution to stochastic functional differential equations with infinite delay where , and are Borel measurable functionals, and is an -dimensional Brownian motion. Without the linear growth condition, we
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