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Facile preparation of pristine graphene using urea/glycerol as efficient stripping agents
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作者 Jianping Chen Weili Shi +5 位作者 Zhaodongfang Gao Tao Wang Shan Wang Lijie Dong Quanling Yang Chuanxi Xiong 《纳米研究:英文版》 SCIE EI CAS CSCD 2018年第2期820-830,共11页
大规模脱落没有缺点并且由一条便宜、 environmentally 友好的线路的很少层 graphene 很长时间是重要挑战。这里,我们显示出那高质量,有高稳定性的很少层 graphene 和低缺点内容能在脲 / 甘油经由一个简单激动人心的过程从自然石墨被... 大规模脱落没有缺点并且由一条便宜、 environmentally 友好的线路的很少层 graphene 很长时间是重要挑战。这里,我们显示出那高质量,有高稳定性的很少层 graphene 和低缺点内容能在脲 / 甘油经由一个简单激动人心的过程从自然石墨被获得,与多达 12 wt.% 的收益。我们也证明这个灵巧的方法能被用于另外的二维的材料的脱落,例如铝二硫化物和硼氮化物。同样准备的 graphene 是有 polyvinylidene 氟化物(PVDF ) 的进一步的 composited 并且合成展出了 0.05 vol.% 的低过滤阀值。加入低(4.5 vol.%) graphene 数量在 graphene-PVDF composites 的热传导性导致了重要增加。 展开更多
关键词 灵巧 代理人 脱衣 油用 高稳定性 二硫化物 热传导性
Research on the Necessity of Building National-level Grape and Cherry Germplasm Resources Bank in Shandong Province 预览
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《农业生物技术:英文版》 CAS 2018年第2期36-39,共4页
关键词 果树资源 山东省 葡萄 银行 公民 工业发展 白兰地酒 应用程序
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共价有机框架材料的设计与制备
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作者 王珊 冯霄 王博 《科学通报》 CSCD 北大核心 2018年第22期2229-2245,共17页
共价有机框架材料(covalent organic frameworks,COFs)是有机构筑基元通过共价键连接而成的晶态多孔高分子材料,因其高比表面积、低密度、高度有序的周期性结构和易于功能化等特点,在气体吸附和存储、光电器件、催化、储能和传感等领... 共价有机框架材料(covalent organic frameworks,COFs)是有机构筑基元通过共价键连接而成的晶态多孔高分子材料,因其高比表面积、低密度、高度有序的周期性结构和易于功能化等特点,在气体吸附和存储、光电器件、催化、储能和传感等领域都展现出了广阔的应用前景.COFs的出现和发展使得人们在一定程度上实现了对二维聚合物和三维聚合物的二级结构和三级结构的精准调控.本文从结构设计和功能设计两方面出发介绍COFs的基本设计理念,总结了COFs粉体、单分子层COFs和COFs膜3种形态COFs材料制备合成方法,最后对COFs材料未来发展方向进行了展望. 展开更多
关键词 共价有机框架材料 结晶多孔聚合物 设计 制备
药学干预对骨科围手术期注射用质子泵抑制剂合理使用的效果评价 预览
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作者 刘慧敏 王珊 +6 位作者 李华 李聪 熊琳 田先地 戢太阳 邵将 陈富超 《医药导报》 CAS 北大核心 2018年第12期1509-1512,共4页
目的 评价药学干预促进注射用质子泵抑制药(PPIs)在骨科围手术期合理预防使用的效果。方法 以临床药师为主体,对骨科手术患者实行注射用PPIs预防使用监控和干预,对干预前阶段(2017年4月)、干预第1阶段(2017年5月)、干预第2阶段(2... 目的 评价药学干预促进注射用质子泵抑制药(PPIs)在骨科围手术期合理预防使用的效果。方法 以临床药师为主体,对骨科手术患者实行注射用PPIs预防使用监控和干预,对干预前阶段(2017年4月)、干预第1阶段(2017年5月)、干预第2阶段(2017年6月)、干预第3阶段(2017年7月)的PPIs使用率、有指征预防使用率、平均使用频次、平均日剂量和平均疗程进行回顾性统计分析,同时比较注射用PPIs的人均消耗金额、与总药费以及住院费用的占比。结果 干预后注射用PPIs的使用率由65.85%降至11.72%,平均疗程由(6.60±5.41) d缩短至(2.88±2.03) d,注射用PPIs人均消耗金额由(247.74±234.79)元降至(126.30±131.78)元,有适应证的用药比例由37.96%提高至76.47%。结论运用药学干预模式可进一步规范骨科手术患者围手术期注射用PPIs的预防使用,并降低患者的经济负担。 展开更多
关键词 质子泵抑制药 预防使用 药学干预 手术 骨科 围手术期
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Potassium 2-(l-hydroxypentyl)-benzoate attenuates neuroinflammatory responses and upregulates heme oxygenase-1 in systemic lipopolysaccharide-induced inflammation in mice
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作者 Chunyang Zhao Weizhen Hou +6 位作者 Hui Lei Longjian Huang Shan Wang Dandan Cui Changhong Xing Xiaoliang Wang Ying Peng 《药学学报:英文版》 CSCD 2017年第4期470-478,共9页
A neuroinflammatory response is commonly involved in the progression of many neurodegenerative diseases. Potassium 2-(1-hydroxypentyl)-benzoate(PHPB), a novel neuroprotective compound, has shown promising effects in t... A neuroinflammatory response is commonly involved in the progression of many neurodegenerative diseases. Potassium 2-(1-hydroxypentyl)-benzoate(PHPB), a novel neuroprotective compound, has shown promising effects in the treatment of ischemic stroke and Alzheimer’s disease(AD). In the present study, the anti-inflammatory effects of PHPB were investigated in the plasma and brain of C57BL/6 mice administered a single intraperitoneal(i.p.) injection of lipopolysaccharide(LPS). Levels of i NOS and the cytokines TNFα, IL-1β and IL-10 were elevated in plasma, cerebral cortex and hippocampus after LPS injection and the number of microglia and astrocytes in cortex and hippocampus were increased. LPS also upregulated the expression of heme oxygenase-1(HO-1) in the cortex and hippocampus. PHPB reduced the levels of i NOS and cytokines in the plasma and brain, decreased the number of microglia and astrocytes and further enhanced the upregulation of HO-1. In addition, PHPB inhibited the LPS-induced phosphorylation of ERK, P38 and JNK. These results suggest that PHPB is a potential candidate in the treatment of neurodegenerative diseases through inhibiting neuroinflammation. 展开更多
关键词 PHPB NEUROINFLAMMATION LPS MAPK Heme oxygenase-1
Synthesis of a novel illite@carbon nanocomposite adsorbent for removal of Cr(Ⅵ) from wastewater
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作者 Gaofeng Wang Shan Wang +2 位作者 Wen Sun Zhiming Sun Shuilin Zheng 《环境科学学报:英文版》 SCIE EI CAS CSCD 2017年第7期62-71,共10页
A novel illite@carbon(I@C) nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process(HTC) using glucose as carbonaceous source and illite as the carrier.The morphology,microstructure... A novel illite@carbon(I@C) nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process(HTC) using glucose as carbonaceous source and illite as the carrier.The morphology,microstructure and surface properties of the prepared nanocomposite adsorbent were analyzed by FESEM,TGA,XRD,FT-IR and Zeta potential measurements.Batch experiments were carried out on the adsorption of Cr(Ⅵ) to determine the adsorption properties of the composite.The adsorption of Cr(Ⅵ) onto the I@C nanocomposite was well described by the pseudo-second-order kinetic model and Langmuir isotherm.Compared with the illite and carbon material(SC) separately,the prepared I@C nanocomposite adsorbent exhibited enhanced adsorption performance for Cr(Ⅵ) with a maximum adsorption capacity of 149.25 mg/g,which was higher than that of most reported adsorbents.In addition,the adsorption process was spontaneous and endothermic based on the adsorption thermodynamics study.The adsorption of Cr(Ⅵ) by I@C was highly p H-dependent and the optimum adsorption occurred at p H 2.0.The Zeta potential analysis results indicated that the electrostatic interactions between anionic Cr(Ⅵ) and the positively charged surface of the adsorbent might be critical to the adsorption mechanism.This study demonstrated that the I@C nanocomposite should be a promising candidate for a low-cost,environmental friendly and highly efficient adsorbent for the removal of toxic Cr(Ⅵ) from wastewater. 展开更多
关键词 纳米复合材料 复合吸附剂 Cr(Ⅵ) 合成废水 伊利石 碳源 吸附性能 表面制备
羟基肉桂酸衍生物的合成及其抗氧化构效关系 预览 被引量:1
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作者 单旺 陈永生 +2 位作者 梁晓为 汪勇 晏日安 《食品工业科技》 CSCD 北大核心 2017年第12期287-291,332共6页
以羟基苯甲醛衍生物和丙二酸为原料,吡啶为溶剂,六水哌嗪为催化剂,通过Knoevenagel缩合反应合成五种羟基肉桂酸。采用熔点分析法、核磁共振氢谱法(_1H Nuclear Magnetic Resonance,_1H NMR)、红外光谱法(IR)、高效液相色谱法(HPLC... 以羟基苯甲醛衍生物和丙二酸为原料,吡啶为溶剂,六水哌嗪为催化剂,通过Knoevenagel缩合反应合成五种羟基肉桂酸。采用熔点分析法、核磁共振氢谱法(_1H Nuclear Magnetic Resonance,_1H NMR)、红外光谱法(IR)、高效液相色谱法(HPLC)对产物的结构和纯度进行鉴定,结合对Fe^3+还原能力、清除DPPH自由基能力等体外抗氧化方法进行抗氧化活性实验,并与羟基苯甲醛衍生物、2,6-二叔丁基-4-甲基苯酚(BHT)和肉桂酸的抗氧化能力进行对比。结果表明:分别得到目标产物——3,4-二羟基肉桂酸、4-羟基-3-甲氧基肉桂酸、3-羟基-4-甲氧基肉桂酸、4-羟基肉桂酸、3-羟基肉桂酸,纯度分别为92.45%、93.14%、99.55%、96.54%、93.50%;3,4-二羟基肉桂酸、4-羟基-3-甲氧基肉桂酸对Fe~(3+)还原能力、清除DPPH自由基能力较强,均高于BHT,且对DPPH自由基的IC_(50)值(半抑制浓度)分别为(11.50±0.02)、(16.57±0.04)、(33.04±0.03)μg/m L;酚羟基是羟基肉桂酸衍生物的抗氧化活性中心,具有邻苯二酚结构或者羟基邻位存在给电子基团的衍生物,具有较高的抗氧化活性;4'位羟基取代衍生物比3'位羟基取代衍生物的抗氧化活性强;苯环上的α,β-不饱和酸共轭结构可以提高酚类化合物的抗氧化活性。 展开更多
关键词 羟基苯甲醛衍生物 合成 羟基肉桂酸衍生物 抗氧化活性 构效关系
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Process analysis of characteristics of the boundary layer during a heavy haze pollution episode in an inland megacity,China 被引量:1
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作者 Shan Wang Tingting Liao +1 位作者 Lili Wang Yang Sun 《环境科学学报:英文版》 SCIE EI CAS CSCD 2016年第2期138-144,共7页
Ground observation data from 8 meteorological stations in Xi’an, air mass concentration data from 13 environmental quality monitoring sites in Xi’an, as well as radiosonde observation and wind profile radar data, we... Ground observation data from 8 meteorological stations in Xi’an, air mass concentration data from 13 environmental quality monitoring sites in Xi’an, as well as radiosonde observation and wind profile radar data, were used in this study. Thereby, the process,causes and boundary layer meteorological characteristics of a heavy haze episode occurring from 16 to 25 December 2013 in Xi’an were analyzed. Principal component analysis showed that this haze pollution was mainly caused by the high-intensity emission and formation of gaseous pollutants(NO2, CO and SO2) and atmospheric particles(PM2.5(fine particles) and PM10(respirable suspended particle). The second cause was the relative humidity and continuous low temperature. The third cause was the allocation of the surface pressure field. The presence of a near-surface temperature inversion at the boundary layer formed favorable stratification conditions for the formation and maintenance of heavy haze pollution. The persistent thick haze layer weakened the solar radiation. Meanwhile, a warming effect in the urban canopy layer and in the transition zone from the urban friction sublayer to the urban canopy was indicated. All these conditions facilitated the maintenance and reinforcement of temperature inversion. The stable atmospheric stratification finally acted on the wind field in the boundary layer, and further weakened the exchange capacity of vertical turbulence. The superposition of a wind field with the horizontal gentle wind induced the typical air stagnation and finally caused the deterioration of air quality during this haze event. 展开更多
关键词 边界层特征 内陆城市 污染事件 地表温度反演 中国 地面观测资料 空气质量
Recent advances of covalent organic frameworks in electronic and optical applications
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作者 Li Ma Shan Wang +1 位作者 Xiao Feng Bo Wang 《中国化学快报:英文版》 SCIE CAS CSCD 2016年第8期1383-1394,共12页
Covalent organic frameworks(COFs) as an emerging class of porous materials have achieved remarkable progress in recent years.Their high surface area,low mass densities,highly ordered periodic structures,and ease of fu... Covalent organic frameworks(COFs) as an emerging class of porous materials have achieved remarkable progress in recent years.Their high surface area,low mass densities,highly ordered periodic structures,and ease of functionalization make COFs exhibit superior potential in gas storage and separation,optoelectronic device and catalysis.This mini review gives a brief introduction of COFs and highlights their applications in electronic and optical fields. 展开更多
关键词 共有原子价器官的框架 Semiconduction 光导 精力存储 Chemosensor
Comparisons of biophysical properties and bioactivities of mono-PEGylated endostatinand an endostatin analog 预览
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《癌症:英文版》 SCIE CAS CSCD 2016年第2期61-68,共8页
Background: Endostatin (ES) is a well-established potent endogenous antiangiogenic factor. An ES variant, calledzinc-binding protein-ES (ZBP-ES), is clinically available; however, its use is limited by rapid rena... Background: Endostatin (ES) is a well-established potent endogenous antiangiogenic factor. An ES variant, calledzinc-binding protein-ES (ZBP-ES), is clinically available; however, its use is limited by rapid renal clearance and shortresidence time. PEGylation has been exploited to overcome these shortcomings, and mono-PEGylated ES (calledM2ES) as well as mono-PEGylated ZBP-ES (MZBP-ES) are developed in our study. This study aimed to compare thebiophysical properties and biological effects of M2ES and MZBP-ES to evaluate their druggability.Methods: Circular dichroism and tryptophan emission fluorescence were used to monitor the conformationalchanges of M2ES and MZBP-ES. Their resistance to trypsin digestion and guanidinium chloride (GdmCI)-inducedunfolding was examined by Coomassie staining and tryptophan em ssion fluorescence, respectively. The biologicaleffects of M2ES and MZBP-ES on endothelial cell migration were eva uated using Transwell migration and woundhealing assays, and the uptake of M2ES and MZBP-ES in endothelial cells was also compared by Western blotting andimmunofluorescence.Results: Structural analyses revealed that M2ES has a more compact tertiary structure than MZBP-ES. Moreover, M2ESwas more resistant to trypsin digestion and GdmCI-induced unfolding compared with MZBP-ES. In addition, althoughM2ES and MZBP-ES showed comparable levels of inhibiting transwell migration and wound healing of endothelialcells, M2ES displayed an increased ability to enter cells compared with MZBP-ES, possibly caused by the enhancedinteraction with nucleolin.Conclusions: M2ES has a more compact tertiary structure, is more stable for trypsin digestion and GdmCI-inducedunfolding, exhibits increased cellular uptake and shows equivalent inhibitory effects on cell migration relative toMZBP-ES, indicating that M2ES is a more promising candidate for anticancer drug development compared withMZBP-ES. 展开更多
关键词 Endostatin PEGylation ANTIANGIOGENIC therapy Drug design Zinc-binding protein-endostatin
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Synthesis, Characterization, and Fluorescence Sensor Property of Polyurethane/Ag2S Nanostrips 预览
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作者 Shan Wang Yi Huang Jian-she Yue 《化学物理学报》 SCIE CAS CSCD 2015年第6期共4页
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Fecal microbiota transplantation broadening its application beyond intestinal disorders 预览 被引量:21
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作者 Meng-QueXu Hai-LongCao +4 位作者 Wei-QiangWang ShanWang Xiao-CangCao FangYan Bang-MaoWang 《世界胃肠病学杂志:英文版》 SCIE CAS 2015年第1期102-111,共10页
Intestinal dysbiosis is now known to be a complication in a myriad of diseases.Fecal microbiota transplantation(FMT),as a microbiota-target therapy,is arguably very effective for curing Clostridium difficile infection... Intestinal dysbiosis is now known to be a complication in a myriad of diseases.Fecal microbiota transplantation(FMT),as a microbiota-target therapy,is arguably very effective for curing Clostridium difficile infection and has good outcomes in other intestinal diseases.New insights have raised an interest in FMT for the management of extra-intestinal disorders associated with gut microbiota.This review shows that it is an exciting time in the burgeoning science of FMT application in previously unexpected areas,including metabolic diseases,neuropsychiatric disorders,autoimmune diseases,allergic disorders,and tumors.A randomized controlled trial was conducted on FMT in metabolic syndrome by infusing microbiota from lean donors or from self-collected feces,with the resultant findings showing that the lean donor feces group displayed increased insulin sensitivity,along with increased levels of butyrate-producing intestinal microbiota.Case reports of FMT have also shown favorable outcomes in Parkinson’s disease,multiple sclerosis,myoclonus dystonia,chronic fatigue syndrome,and idiopathic thrombocytopenic purpura.FMT is a promising approach in the manipulation of the intestinal microbiota and has potential applications in a variety of extra-intestinal conditions associated with intestinal dysbiosis. 展开更多
关键词 FECAL MICROBIOTA TRANSPLANTATION INTESTINAL microb
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A Novel Thermosensitive In-situ Gel of Gabexate Mesilate for Treatment of Traumatic Pancreatitis:An Experimental Study 预览
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作者 高菡静 宋青 +5 位作者 吕发勤 汪姗 王一茹 罗渝昆 梅兴国 唐杰 《华中科技大学学报:医学英德文版》 SCIE CAS 2015年第5期707-711,共5页
Gabexate mesilate(GM) is a trypsin inhibitor,and mainly used for treatment of various acute pancreatitis,including traumatic pancreatitis(TP),edematous pancreatitis,and acute necrotizing pancreatitis. However,due to t... Gabexate mesilate(GM) is a trypsin inhibitor,and mainly used for treatment of various acute pancreatitis,including traumatic pancreatitis(TP),edematous pancreatitis,and acute necrotizing pancreatitis. However,due to the characteristics of pharmacokinetics,the clinical application of GM still needs frequently intravenous administration to keep the blood drug concentration,which is difficult to manage. Specially,when the blood supply of pancreas is directly damaged,intravenous administration is difficult to exert the optimum therapy effect. To address it,a novel thermosensitive in-situ gel of gabexate mesilate(GMTI) was developed,and the optimum formulation of GMTI containing 20.6%(w/w) P-407 and 5.79%(w/w) P188 with different concentrations of GM was used as a gelling solvent. The effective drug concentration on trypsin inhibition was examined after treatment with different concentrations of GMTI in vitro,and GM served as a positive control. The security of GMTI was evaluated by hematoxylin-eosin(HE) staining,and its curative effect on grade Ⅱ pancreas injury was also evaluated by testing amylase(AMS),C-reactive protein(CRP) and trypsinogen activation peptide(TAP),and pathological analysis of the pancreas. The trypsin activity was slightly inhibited at 1.0 and 5.0 mg/m L in GM group and GMTI group,respectively(P<0.05 vs. P-407),and completely inhibited at 10.0 and 20.0 mg/m L(P<0.01 vs. P-407). After local injection of 10 mg/m L GMTI to rat leg muscular tissue,muscle fiber texture was normal,and there were no obvious red blood cells and infiltration of inflammatory cells. Furthermore,the expression of AMS,CRP and TAP was significantly increased in TP group as compared with control group(P<0.01),and significantly decreased in GM group as compared with TP group(P<0.01),and also slightly inhibited after 1.0 and 5.0 mg/m L GMTI treatment as compared with TP group(P<0.05),and significantly inhibited after 10.0 and 20.0 mg/m L GMTI treatment as compared with TP group(P<0.01). HE staining results demonstrated that panc 展开更多
关键词 急性胰腺炎 治疗效果 创伤性 凝胶 原位 蛋白酶抑制剂 急性坏死性胰腺炎 胰蛋白酶活性
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不同腰围水平与非酒精性脂肪肝发病风险的关系 预览 被引量:1
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作者 王珊 佟博 +4 位作者 张海玲 蒋晓忠 张杰 段和力 吴寿岭 《世界华人消化杂志》 CAS 2015年第20期3219-3225,共7页
目的:探讨开滦研究人群不同腰围水平与非酒精性脂肪肝(non-alcoholic fatty liver disease,NAFLD)发病风险的关系.方法:采用前瞻性队列研究方法,以参加2006-2007年度健康体检的55358例无NAFLD的开滦集团在职及离退休员工作为观察队... 目的:探讨开滦研究人群不同腰围水平与非酒精性脂肪肝(non-alcoholic fatty liver disease,NAFLD)发病风险的关系.方法:采用前瞻性队列研究方法,以参加2006-2007年度健康体检的55358例无NAFLD的开滦集团在职及离退休员工作为观察队列,纳入最终统计分析的有效数据为36978例,依据基线腰围四分位数将观察对象分为4组,比较4组2012-2013年度健康体检时NAFLD的发病率,用多因素Logistic回归分析不同腰围水平与NAFLD发病风险的关系.结果:(1)按基线腰围四分位数分组,NAFLD发病率分别为13.5%、26.0%、31.6%和38.4%,差异有统计学意义(P〈0.01).按性别分层后,男性4组NAFLD发病率分别为13.4%、24.7%、30.3%和38.9%,女性4组NAFLD发病率分别为13.6%、28.8%、36.5%和36.0%;(2)影响NAFLD发病的多因素Logistic回归分析显示,校正年龄、性别及多种混杂因素后,与第一分位组比较,腰围第二、三、四分位组NAFLD的发病风险均增加,OR值分别为1.72、1.91和2.04.在不同性别人群中校正上述混杂因素后,男性OR值分别为1.66、1.87和2.19,女性OR值分别1.60、1.80、1.46.结论:腰围增加会增加NAFLD的发病风险. 展开更多
关键词 非酒精性脂肪肝 腰围 队列研究
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MOOC对高等教育的影响和应对措施浅析 预览 被引量:2
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作者 赵海涛 王杉 马东堂 《教育进展》 2014年第5期104-111,共8页
MOOC (Massive Open Online Course)即“大规模在线开放课程”,采用在线的方式来实现基于互联网的课程学习、互动、共享和测试,它被认为是对传统高等教育模式和产业的颠覆性创新,近年来受到了教育界的高度关注。深入分析和研究MOOC模式... MOOC (Massive Open Online Course)即“大规模在线开放课程”,采用在线的方式来实现基于互联网的课程学习、互动、共享和测试,它被认为是对传统高等教育模式和产业的颠覆性创新,近年来受到了教育界的高度关注。深入分析和研究MOOC模式对高等教育带来的影响,既有利于高等教育的健康全面发展,也是MOOC本身可持续发展的需求。对MOOC课程对高等教育带来的改变、高等教育者应采取的态度和应对措施进行了分析,总结了在辅导学生选修MOOC课程和建设MOOC课程实践过程的一些体会,并对未来MOOC的发展进行了展望,旨在推动大规模在线开放课程实践的建设及运用。 展开更多
关键词 MOOC 高等教育 影响分析 研究与实践
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Chairman’s government background, excess employment and government subsidies: Evidence from Chinese local state-owned enterprises 被引量:1
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作者 Xiongyuan Wang Shan Wang 《中国会计学刊:英文版》 2013年第1期50-73,共24页
Local state-owned enterprises(SOEs) in China continue to face government interference in their operations. They are influenced both by the government’s'grabbing hand' and by its 'helping hand.' Our st... Local state-owned enterprises(SOEs) in China continue to face government interference in their operations. They are influenced both by the government’s'grabbing hand' and by its 'helping hand.' Our study examines how SOE chairmen with connections to government influence their firm’s employment policies and the economic consequences of overstaffing. Using a sample of China’s listed local state-owned enterprises, we find that the scale of overstaffing in these SOEs is negatively related to the firms’ political connections to government. However,this relationship turns positive when the firm’s chairman has a government background. Appointing chairmen who have government backgrounds is a mechanism through which the government can intervene in local SOEs and influence firms’ staffing decisions. We also find that in compensation for the expenses of overstaffing, local SOEs receive more government subsidies and bank loans.However, the chairmen themselves do not get increased pay or promotion opportunities for supporting overstaffing. Further analysis indicates that whereas the 'grabbing hand' of government does harm to a firm’s economic performance, the 'helping hand' provides only weak positive effects, and such government intervention actually reduces the efficiency of social resource allocation. 展开更多
关键词 GOVERNMENT BACKGROUND EXCESS EMPLOYMENT GOVERNMENT
碱性蛋白酶提取杜仲籽粕蛋白的工艺优化 预览
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作者 吴凡 蒲灵操 +4 位作者 单旺 杨朔俊 苏超 黄群 麻成金 《粮食科技与经济》 2013年第6期54-57,共4页
采用二次通用旋转组合设计实验优化超声波辅助碱性蛋白酶提取杜仲籽粕蛋白工艺。在单因素实验基础上,选择pH值、碱性蛋白酶用量、酶解温度与酶解时间为考察因素,以杜仲籽粕蛋白提取率为响应值建立回归数学模型,对杜仲籽粕蛋白提取工... 采用二次通用旋转组合设计实验优化超声波辅助碱性蛋白酶提取杜仲籽粕蛋白工艺。在单因素实验基础上,选择pH值、碱性蛋白酶用量、酶解温度与酶解时间为考察因素,以杜仲籽粕蛋白提取率为响应值建立回归数学模型,对杜仲籽粕蛋白提取工艺条件进行优化。结果表明,最佳提取工艺条件为:pH10,碱性蛋白酶用量320u/g,酶解温度55℃,酶解时间115rain。在此优化条件下,杜仲籽粕蛋白提取率可迭74.28%。 展开更多
关键词 杜仲籽粕 蛋白提取 碱性蛋白酶 二次通用旋转组合设计
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西安雾日和霾日时空特征分析 预览
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作者 王珊 孟小荣 金丽娜 《农业科学与技术:英文版》 CAS 2013年第7期1037-1040,1048共5页
利用1960~2012年西安区域7个气象站的历史地面观测资料,统计分析了西安地区雾日、轻雾日及霾日的时空变化特征。结果表明,1960~2012年西安区域雾日分布呈近山区多、平原区少的特点;轻雾日的分布呈城区多发、郊区少发的特征;霾日在城区... 利用1960~2012年西安区域7个气象站的历史地面观测资料,统计分析了西安地区雾日、轻雾日及霾日的时空变化特征。结果表明,1960~2012年西安区域雾日分布呈近山区多、平原区少的特点;轻雾日的分布呈城区多发、郊区少发的特征;霾日在城区为高发区,近郊次之,远郊最少。西安地区年平均雾日数呈现先增加后减少的变化特征,轻雾日数以9.0d/10a的速率呈波动性显著增加趋势,霾日以-7.7d/10a的速率呈波动性显著减少趋势。西安地区雾日数在年内呈单谷型分布,全年最低值出现在夏季6月(0.2d),冬季12月出现最高值(3.8d);轻雾日数在年内呈"V"型分布,全年轻雾日数最低值出现在6月(7.6d),冬季12月份出现最多(17.4d);霾日数在年内呈"U"型分布,春末(5月)~初秋(9月)霾日出现频率在年内变化曲线上表现为一个宽广的"U"型底部,在冬季1月份上升至最高值(6.1d)。 展开更多
关键词 轻雾 时空分布 西安
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聚碳酸酯在中国海拉尔地区户外自然老化失效分析 预览 被引量:3
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作者 周名勇 江龙 +4 位作者 王杉 周雨力 刘晗 李光宪 淡宜 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2013年第12期66-69,共4页
采用红外光谱、紫外光谱、凝胶渗透色谱和扫描电子显微镜技术并结合拉伸性能测试分析了聚碳酸酯在中国海拉尔地区户外自然老化前后的光学特性、相对分子质量、表面形貌和力学性能的变化,研究了12个月内聚碳酸酯在该地区户外自然老化失... 采用红外光谱、紫外光谱、凝胶渗透色谱和扫描电子显微镜技术并结合拉伸性能测试分析了聚碳酸酯在中国海拉尔地区户外自然老化前后的光学特性、相对分子质量、表面形貌和力学性能的变化,研究了12个月内聚碳酸酯在该地区户外自然老化失效规律,揭示了导致聚碳酸酯老化失效的结构原因,为合理使用聚碳酸酯材料提供进一步的实验和理论支撑。分析结果表明:老化后,PC分子结构中产生酚类、酮类等物质,1个月内试样显著变黄,随后黄色指数持续增加;表层相对分子质量1个月内显著降低,随后持续降低,中间层相对分子质量变化不大;6个月后试样表面产生裂纹并扩展至本体内,导致PC拉伸强度和拉伸断裂伸长率显著降低,材料由韧性破坏变为脆性破坏。 展开更多
关键词 聚碳酸酯 自然老化 性能 结构 相对分子质量
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Screening of Substrates of Protein Arginine Methyltransferase 1 in Glioma 预览
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作者 Shan Wang Xiao-chao Tan Bin Yang Bin Yin Xiao-zhong Peng 《中国医学科学杂志:英文版》 CAS CSCD 2012年第1期 1-6,共6页
Objective To screen the asymmetric dimethyl arginines (ADMA)-containing proteins which could combine with protein arginine methyltransferase 1 (PRMT1). Methods Western blot was adopted to identify the expression of PR... Objective To screen the asymmetric dimethyl arginines (ADMA)-containing proteins which could combine with protein arginine methyltransferase 1 (PRMT1). Methods Western blot was adopted to identify the expression of PRMT1 and the proteins with ADMA in glioma cell lines and normal brain tissues, and then to detect the changes of ADMA level after knock-down of PRMT1 with RNAi transfection in U87MG cells. Co-Immunoprecipitation (Co-IP), western blot, and sliver staining were employed to screen the candidate binding proteins of PRMT1. Then liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify the binding proteins of PRMT1. Results The expression of PRMT1 and some levels of ADMA were higher in glioma cell lines than in normal brain tissues. After knocking down PRMT1, some ADMA levels were found declined. After screening the binding proteins of PRMT1 with Co-IP and LC-MS/MS, 26 candidate binding proteins were identified. Among them, 6 candidate proteins had higher ions scores (>38) and bioinformation analysis predicted that SEC23-IP, ANKHD1-EIF4EBP3 protein, and 1-phosphatidylinositol-3-phosphate 5-kinase isoform 2 had possible methylated aginine sites. Conclusions The high expression of PRMT1 in glioma may induce the change of ADMA levels. Altogether 26 candidate proteins were identified, which contain ADMA and specifically bind with PRMT1. 展开更多
关键词 结合蛋白质 甲基转移酶 脑胶质瘤 精氨酸 筛选 LC-MS/MS 基质 免疫印迹
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