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中华卫生应急电子杂志 2015年第6期1卷 18-24页

作者：楚鹰岳茂兴包卿郑旭文沈文明刘政周培根李瑛卞晓星黄琴梅尹进南梁华平江苏大学附属武进医院江苏常州213002 第三军医大学创伤烧伤与复合伤国家重点实验室重庆400042

目的探讨维生素B_6联用20AA复方氨基酸治疗创伤性凝血病有关机制。方法 114只雄性SD大鼠,按随机数字表法进行分组。创伤性凝血病大鼠模型建立实验使用60只大鼠,假手术组(10只),模型组(50只),其中模型组分别于造模后4 h,6 h,12 h,24 h和4... 详细信息

目的探讨维生素B_6联用20AA复方氨基酸治疗创伤性凝血病有关机制。方法 114只雄性SD大鼠,按随机数字表法进行分组。创伤性凝血病大鼠模型建立实验使用60只大鼠,假手术组(10只),模型组(50只),其中模型组分别于造模后4 h,6 h,12 h,24 h和48 h时间点采集标本,每个时间点10只;新疗法疗效实验使用24只大鼠,分为假手术组,9%等渗盐水对照组,维生素B_6与20AA复方氨基酸联合治疗组,共3组,每组8只;新疗法作用机制实验使用30只大鼠,正常组3只、假手术组3只、新疗法组与对照组各12只,其中新疗法组与对照组分别在伤后4 h,6 h,12 h及24 h四个时间点采集标本,每个时间点3只。通过造成大鼠重型颅脑损伤、双股骨骨折、开腹及腹主动脉放血20%,制成大鼠多发伤模型,进行干预后,按各时间点采集标本进行相应检测。创伤性凝血病大鼠模型建立实验采用血栓弹力图检测凝血功能变化,新疗法疗效实验分别采用血栓弹力图与凝血4项检测检测凝血功能变化,新疗法作用机制实验采用实时定量PCR检测凝血因子基因表达变化。结果 (1)创伤性凝血病大鼠模型建立实验:R值(反应时间)48h达到高峰,24 h,48 h与正常组比较具有统计学差异(P<0.05),K值(血块生成时间)和Angle值(血块生成率)各组变化不大,与正常组相比较无统计学意义;MA(最大宽度值)4 h开始延长,48 h达到高峰,24 h,48 h与正常组比较具有显著统计学差异(P<0.01)。(2)新疗法疗效实验:新疗法组与对照组比较,血栓弹力图R值为(2.24±0.68)min,显著低于对照组的(3.21±0.30)min(P<0.05);新疗法组血栓弹力图Angle值为(81.98±1.78)°,显著高于对照组的(79.54±2.13)°(P<0.05)。传统凝血试验结果:凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、凝血酶时间(TT)新疗法治疗组均比对照组低,而纤维蛋白原(FIB)新疗法治疗组高于对照组,但其差异不显著。(3)新疗法作用机制实验:与正常组相比,除FⅪ与FⅩⅢA亚基外,新疗法组和对照组的肝脏凝血因子基因表达明显上调,但随着造模时间延长,其表达水平逐渐下降;新疗法组与对照组相比,肝脏凝血因子基因表达水平更高,其差异具有统计学意义(P<0.05)。结论建立与临床基本相符的大鼠创伤性凝血病模型,利用该模型验证了维生素B_6联用20AA复方氨基酸疗法对创伤性凝血病大鼠凝血功能的改善作用,并发现该新疗法能够通过提高肝脏凝血因子基因mRNA表达水平,从而改善动物模型的凝血功能。

关键词：创伤性凝血病血栓弹力图维生素B620AA复方氨基酸凝血因子基因

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Regulation of Mammalian Target of Rapamycin Complex 1 by Bcl-2 and Bcl-X_L Proteins

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JOURNAL OF BIOLOGICAL CHEMISTRY 2013年第40期288卷 28824-28830页

作者： Zou, Huafei Lai, Yumei Zhao, xuwen Yan, Gonghong Ma, Dongzhu Cardenes, Nayra Shiva, Sruti liu, Yongjian Bai, Xiaochun Jiang, Yong Jiang, Yu Univ Pittsburgh Sch Med Dept Pharmacol & Chem Biol Pittsburgh PA 15261 USA Univ Pittsburgh Sch Med Vasc Med Inst Pittsburgh PA 15261 USA Southern Med Univ Dept Pathol Sch Basic Med Sci Guangzhou 510515 Guangdong Peoples R China Southern Med Univ Dept Cell Biol Sch Basic Med Sci Guangzhou 510515 Guangdong Peoples R China

Mammalian target of rapamycin complex 1 (mTORC1) is a key regulator of cell growth and metabolism. Its activity is controlled by various types of signals, including growth factors, nutrients, and stresses. In this study, we show that changes in expression levels of two antiapoptotic proteins, Bcl-2 and Bcl-X-L, also affect mTORC1 signaling activity. In cells overexpressing Bcl-X-L, mTORC1 activity is increased and becomes less sensitive to growth factor or nutrient conditions. In contrast, reduction in expression levels of the two antiapoptotic proteins inhibits mTORC1 signaling activity. Our results suggest that the effect of Bcl-2 and Bcl-X-L on mTORC1 is mediated by FKBP38, an inhibitor of mTORC1. The two proteins compete with mTORC1 for FKBP38 binding and hence alter mTORC1 activity. This study reveals a novel cross-talk between Bcl-2/X-L and mTORC1 signaling, which is likely to contribute to cancer development.

关键词： Bcl-2 Mitochondria mTOR Complex (mTORC) S6 Kinase Signaling Bcl-XL FKBP38 mTORC1

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Research on Image Matching Algorithm Based on Local Invariant Features

Research on Image Matching Algorithm Based on Local Invarian...

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International Conference on Intelligent Information Hiding and Multimedia Signal Processing (IIHMSP)

作者： Jiaqi liu Qiang Wu xuwen Li College of Electronic Information and Control Engineering Beijing University of Technology Beijing China College of Life Science and Bioengineering Beijing University of Technology Beijing China

As an important foundation for image-guided technology, image matching technique is the key technology of modern war. This paper proposes a new algorithm of affine invariant detector and descriptor of local invariant feature points, starting from feature point detection and description point of view, making up the traditional feature point extraction defects of small number and types. Meantime, proposes an improved similarity measure method based on the previously proposed new feature point detection and description algorithm, it improves the matching accuracy and real-time performance. Finally, compares the experiment results of SURF, SIFT and the improved algorithm proposed in this paper, the experimental results shows that the feature points extracted by the improved algorithm has fully affine invariance, and improved the accuracy and speed of image matching algorithm efficiently.

关键词： Feature extraction Algorithm design and analysis Signal processing algorithms Image matching Accuracy Transforms Detectors

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Structural Determinants for the Strict Monomethylation Activity by Trypanosoma brucei Protein Arginine Methyltransferase 7

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STRUCTURE 2014年第5期22卷 756-768页

作者： Wang, Chongyuan Zhu, Yuwei Caceres, Tamar B. liu, Lei Peng, Junhui Wang, Junchen Chen, Jiajing Chen, xuwen Zhang, Zhiyong Zuo, Xiaobing Gong, Qingguo Teng, Maikun Hevel, Joan M. Wu, Jihui Shi, Yunyu Univ Sci & Technol China Hefei Natl Lab Phys Sci Microscale & Sch Life Sci Hefei 230027 Anhui Peoples R China Utah State Univ Dept Chem & Biochem Logan UT 84322 USA Argonne Natl Lab Adv Photon Source Chicago IL 60437 USA

Trypanosoma brucei protein arginine methyltransferase 7 (TbPRMT7) exclusively generates monomethylarginine (MMA), which directs biological consequences distinct from that of symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). However, determinants controlling the strict monomethylation activity are unknown. We present the crystal structure of the TbPRMT7 active core in complex with S-adenosyl-L-homocysteine (AdoHcy) and a histone H4 peptide substrate. In the active site, residues E172, E181, and Q329 hydrogen bond the guanidino group of the target arginine and align the terminal guanidino nitrogen in a position suitable for nucleophilic attack on the methyl group of S-adenosyl-L-methionine (AdoMet). Structural comparisons and isothermal titration calorimetry data suggest that the TbPRMT7 active site is narrower than those of protein arginine dimethyltransferases, making it unsuitable to bind MMA in a manner that would support a second turnover, thus abolishing the production of SDMA and ADMA. Our results present the structural interpretations for the monomethylation activity of TbPRMT7.

关键词： PROTEIN arginine methyltransferases METHYLATION TRYPANOSOMA brucei ASYMMETRIC dimethylarginine CRYSTAL structure PEPTIDES HYDROGEN bonding

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Localized recrystallization and cracking of lead-free solder interconnections under thermal cycling

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JOURNAL OF MATERIALS RESEARCH 2011年第16期26卷 2103-2116页

作者： Chen, Hongtao Mueller, Maik Mattila, Tonu Tuomas Li, Jue liu, xuwen Wolter, Klaus-Juergen Paulasto-Krockel, Mervi Aalto Univ Sch Sci & Technol Dept Elect FIN-00076 Aalto Finland Harbin Inst Technol Shenzhen Grad Sch Shenzhen 518055 Peoples R China Tech Univ Dresden Elect Packaging Lab IAVT D-01062 Dresden Germany Aalto Univ Sch Chem Technol Dept Mat Sci & Engn Mat Sci Lab FIN-00076 Aalto Finland

The failure mechanism of lead-free solder interconnections of chip scale package-sized Ball Grid Array (BGA) component boards under thermal cycling was studied by employing cross-polarized light microscopy, scanning electronic microscopy, electron backscatter diffraction, and nanoindentation. It was determined that the critical solder interconnections were located underneath the chip corners, instead of the corner most interconnections of the package, and the highest strains and stresses were concentrated at the outer neck regions on the component side of the interconnections. Observations of the failure modes were in good agreement with the finite element results. The failure of the interconnections was associated with changes of microstructures by recrystallization in the strain concentration regions of the solder interconnections. Coarsening of intermetallic particles and the disappearance of the boundaries between the primary Sn cells were observed in both cases. The nanoindentation results showed lower hardness of the recrystallized grains compared with the non-recrystallized regions of the same interconnection. The results show that failure modes are dependent on the localized microstructural changes in the strain concentration regions of the interconnections and the crack paths follow the networks of grain boundaries produced by recrystallization.

关键词： Microstructure Soldering Fatigue

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Zacopride selectively activates the Kir2.1 channel via a PKA signaling pathway in rat cardiomyocytes

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Science China(Life Sciences) 2013年第9期56卷 788-796页

作者： ZHANG Li liu QingHua liu ChengFang ZHAI xuwen FENG QiLong XU RuiLing CUI XiangLi ZHAO ZhiQing CAO JiMin WU BoWei Department of Physiology and the Key Laboratory of Cellular Physiology Ministry of Education Shanxi Medical University Department of Pathophysiology Shanxi Medical University Department of Biomedical Sciences Mercer University School of Medicine Department of Physiology Institute of Basic Medical Sciences Chinese Academy of Medical Sciences School of Basic Medicine Peking Union Medical College

We recently reported that zacopride is a selective inward rectifier potassium current (IK1 ) channel agonist, suppressing ventricular arrhythmias without affecting atrial arrhythmias. The present study aimed to investigate the unique pharmacological properties of zacopride. The whole-cell patch-clamp technique was used to study IK1 currents in rat atrial myocytes and Kir2.x currents in human embryonic kidney (HEK)-293 cells transfected with inward rectifier potassium channel (Kir)2.1, Kir2.2, Kir2.3, or mutated Kir2.1 (at phosphorylation site S425L). Western immunoblots were performed to estimate the relative protein expression levels of Kir2.x in rat atria and ventricles. Results showed that zacopride did not affect the IK1 and transmembrane potential of atrial myocytes. In HEK293 cells, zacopride increased Kir2.1 homomeric channels by 40.7%±9.7% at 50 mV, but did not affect Kir2.2 and Kir2.3 homomeric channels, and Kir2.1-Kir2.2, Kir2.1-Kir2.3 and Kir2.2-Kir2.3 heteromeric channels. Western immunoblots showed that similar levels of Kir2.3 protein were expressed in rat atria and ventricles, but atrial Kir2.1 protein level was only 25% of that measured in the ventricle. In addition, 5-hydroxytryptamine (5-HT) 3 receptor was undetectable, whereas 5-HT 4 receptor was weakly expressed in HEK293 cells. The Kir2.1-activating effect of zacopride in these cells was abolished by inhibition of protein kinase A (PKA), but not PKC or PKG. Furthermore, zacopride did not activate the mutant Kir2.1 channel in HEK293 cells but selectively activated the Kir2.1 homomeric channel via a PKA-dependent pathway, independent to that of the 5-HT receptor.

关键词： zacopride inward rectifier potassium channel 5-HT receptor protein kinase

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Occludin Localizes to Centrosomes and Modifies Mitotic Entry

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JOURNAL OF BIOLOGICAL CHEMISTRY 2011年第35期286卷 30847-30858页

作者： Runkle, E. Aaron Sundstrom, Jeffrey M. Runkle, Kristin B. liu, xuwen Antonetti, David A. Univ Michigan Kellogg Eye Ctr Ann Arbor MI 48105 USA Penn State Univ Coll Med Dept Cellular & Mol Physiol Hershey PA 17033 USA Penn State Univ Coll Med Dept Ophthalmol Hershey PA 17033 USA

Proper control of cell cycle progression and barrier function are essential processes to the maintenance of epithelial cell homeostasis. The contribution of tight junction proteins to barrier function is well established, whereas their contribution to cell cycle control is only beginning to be understood. Centrosomes are the principal microtubule organizing centers in eukaryotic cells and centrosome duplication and separation are linked to the cell cycle and mitotic entry. Here we demonstrate that occludin localizes with centrosomes in Madin-Darby canine kidney cells. Immunocytochemistry and biochemical fractionation studies reveal occludin localizes with centrosomes during interphase and occludin Ser-490 phosphorylation at centrosomes increases with mitotic entry. Stable expression of aspartic acid phosphomimetic (S490D) results in centrosomal localization of occludin and increases cell numbers. Furthermore, we provide evidence that occludin regulates centrosome separation and mitotic entry as the nonphosphorylatable alanine mutation (S490A) impedes centrosome separation, delays mitotic entry, and reduces proliferation. Collectively, these studies demonstrate a novel location and function for occludin in centrosome separation and mitosis.

关键词： Cell Cycle Cell Junctions Centrosome Tight Junctions Tubulin MDCK Cells Occludin Phosphorylation

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Design and Implementation of Electronic Image Stabilization System Based on Dual-Core DSP

Design and Implementation of Electronic Image Stabilization ...

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International Conference on Intelligent Information Hiding and Multimedia Signal Processing (IIHMSP)

作者： Haolong Zhang Qiang Wu Tianqi liu xuwen Li College of Electronic Information and Control Engineering Beijing University of Technology Beijing China College of Life Science and Bioengineering Beijing University of Technology Beijing China

Electronic image stabilization (EIS) technology is an important research area of video processing and computer vision. This paper presented a set of fast and parallel EIS algorithms. Firstly, this paper proposed a fast local motion vector (LMV) estimation algorithm based on the FAST feature to solve the problem that the traditional algorithm is too complex. Secondly, a parallel global motion vector (GMV) algorithm based on image division is designed, which computes every LMV simultaneously, and then estimates the GMV by all LMVs. Finally, based on the proposed algorithm, an EIS systems based on BF609 dual-core DSP processor is designed and implemented. Experiment results show that the algorithm and system presented in this thesis can effectively stabilize jittery video and achieve high real-time performance. When dealing with PAL standard video, the total time cost is less than 40ms.

关键词： Algorithm design and analysis Feature extraction Streaming media Motion estimation Jitter Signal processing algorithms Vectors

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Downregulation of Skp2 inhibits the growth and metastasis of gastric cancer cells in vitro and in vivo

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TUMOR BIOLOGY 2013年第1期34卷 181-192页

作者： Wei, Zheng Jiang, Xian liu, Fengjun Qiao, Haiquan Zhou, Baoguo Zhai, Bo Zhang, Lianfeng Zhang, xuwen Han, Likun Jiang, Hongchi Krissansen, Geoffrey W. Sun, Xueying Harbin Med Univ Affiliated Hosp 1 Dept Gen Surg Hepatosplen Surg Ctr Harbin 150001 Peoples R China Shandong Univ Qilu Hosp Dept Gen Surg Jinan 250100 Peoples R China Univ Auckland Fac Med & Hlth Sci Dept Mol Med & Pathol Auckland 1005 New Zealand

S-phase kinase-associated protein-2 (Skp2) is overexpressed in human cancers and associated with poor prognosis. Skp2 acts as an oncogenic protein by enhancing cancer cell growth and tumor metastasis. The present study has demonstrated that small hairpin RNA (shRNA)-mediated downregulation of Skp2 markedly inhibits the viability, proliferation, colony formation, migration, invasion, and apoptosis of human gastric cancer MGC803 cells, which express a high level of Skp2. In contrast, Skp2 shRNA had only a slight effect on the above properties of BGC823 cells, which express a low level of Skp2. In accord, knockdown of Skp2 suppressed the ability of MGC803 cells to form tumors and to metastasize to the lungs of mice, and the growth of established tumors, by inhibiting cell proliferation and enhancing cell apoptosis. In contrast, overexpression of Skp2 promoted tumorigenesis of BGC823 cells in mice. Skp2 depletion induced cell cycle arrest in the G(1)/S phase by upregulating p27, p21, and p57 and downregulating cyclin E and cyclin-dependent kinase 2. Skp2 depletion also increased caspase-3 activity, impeded the ability of cells to form filopoidia and locomote, upregulated RECK (reversion-inducing cysteine-rich protein with kazal motifs), and downregulated matrix metalloproteinase (MMP)-2 and MMP-9 activity and expression. The results suggest that downregulating Skp2 warrants investigation as a promising strategy to treat gastric cancers that express high levels of Skp2.

关键词： S-phase kinase-associated protein-2 Gastric cancer Proliferation Cell cycle Metastasis p27

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广州地区地毯式屋顶绿化植物筛选及其评价

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热带农业科学 2014年第12期34卷 98-104页

作者：张继方张俊涛刘文王伟贺漫媚李许文代色平广州市园林科学研究所/广州市景观建筑重点实验室广东广州510405

通过对广州地区广泛收集引种的乡土植物,以及现有栽培的地毯式屋顶绿化植物种类品种的栽培观察,初步筛选适合广州地区地毯式屋顶绿化的植物共39科65属85个种类品种。利用自行构建的广州地区地毯式屋顶绿化综合评价模型对85个种类品种进... 详细信息

通过对广州地区广泛收集引种的乡土植物,以及现有栽培的地毯式屋顶绿化植物种类品种的栽培观察,初步筛选适合广州地区地毯式屋顶绿化的植物共39科65属85个种类品种。利用自行构建的广州地区地毯式屋顶绿化综合评价模型对85个种类品种进行评价,其中有21个种类品种适合在广州地区地毯式屋顶绿化中大规模推广应用。

关键词：地毯式屋顶绿化植物筛选评价广州

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