136 research outputs found
The Research on Supply Chain Resilience of Automobile Injection Molding
供应链管理已经发展为企业的“第三利润源”。但由于供应链的各种不确定性和供应链风险,使得供应链的效率不尽人意。近年自然灾害频发、恐怖袭击、社会事件乃至政治事件层出不穷,这些突发事件不断导致供应链中断事件发生。为了应对不确定性和脆弱性给供应链管理所带来的挑战,预防和处理中断事件,研究汽车供应链弹性愈发重要。FTK公司是一家注塑为主的通讯电子行业转型做汽车产品的汽车注塑供应商。近年来,两次重大中断事故,导致大量的赔偿损失,也影响了供应链关系。对FTK汽车注塑供应链弹性分析、评价并改善,并提高其竞争力,具有十分重要的理论与实际意义。 本文运用文献法、运用归纳、演绎、推理等理论分析方法进行分析,进而对...Supply chain management has become the third profit resource of enterprises. However, due to the supply chain uncertainty and risk, the efficiency of supply chain is not satisfied. The interruption of supply chain occurred frequently in recent years, incurred by natural disasters, terrorist attacks, social or political events. In order to fulfill the challenges of uncertainty and vulnerability, it...学位:工商管理硕士院系专业:管理学院_工商管理硕士(工商管理硕士)学号:1792011115090
Quantify the sources of oxygen consuming organic material in the hypoxic zone in the East China Sea off the Changjiang Estuary
20世纪50年代以来,随着经济的高速发展,人类活动已经严重影响了区域生态环境,近海环境中缺氧区的报道不断增多,已成为全球性的重大环境问题。普遍认为,水体的层化和营养盐的大量输入引发的藻类过度繁殖及其后续的降解耗氧是造成近海区域缺氧的主要原因;但也有研究认为,河流直接输入的有机物是缺氧区耗氧有机物的另一种可能的来源;目前对河流输入的外源有机物和浮游植物自生的有机物在维持河口、湖泊耗氧呼吸作用的相对重要性还不清楚,所以,甄别和定量研究缺氧区耗氧有机物来源意义重大。 本论文以长江口缺氧区作为主要研究案例,通过端元混合模式,甄别水团混合和生物地球化学反应对溶解无机碳浓度和同位素组成的影响,对有机碳的...Hypoxia, typically defined as a water body with dissolved oxygen (DO)学位:理学硕士院系专业:海洋与环境学院_海洋化学学号:2242010115132
肾脏-胰岛联合移植研究进展
糖尿病肾病是糖尿病最严重的并发症,可通过间质及肾小管纤维化等机制导致肾脏功能衰竭,最终进展为终末期肾脏病(end stage renal disease,ESRD)[1-2]。既往认为,糖尿病肾病及其他慢性肾病患者更容易死于心血管疾病而不是ESRD,但是据一份2型糖尿病(type 2 diabetes mellitus,T2DM)随访统计,ESRD导致的死亡比心血管疾病更为
Optimization of crude enzyme preparation methods for analysis of glutamine synthetase activity in phytoplankton and field samples
Glutamine synthetase (GS) is an important enzyme involved in nitrogen assimilation and metabolism in marine phytoplankton. However, little work has been done in situ due to the limitation of crude enzyme preparation methods. In this study, three enzyme preparation methods, high-speed centrifugation (HC, <10 000 g), ultracentrifugation (UC, 70 000 g), and ultrafiltration (UF) with 100 k mu molecular weight cutoff, were compared using two diatom species (Asterionellopsis glacialis and Thalassiosira weissflogii), and two dinoflagellate species (Alexandrium catenella and Prorocentrum donghaiense) as experimental materials together with field samples collected from Xiamen Harbor, China. The results showed that HC is the best method to prepare crude enzymes for glutamine synthetase activity (GSA) in diatom species and diatom-dominant samples, while UF is the best method to extract GS from dinoflagellate species and dinoflagellate-dominant samples. For the HC method, the optimal centrifugal speed and time were 10 000 g and 35 min, respectively, and under these conditions, the highest GSA was obtained in all samples. This study indicates that both methods (HC and UF) overcome the limitation of centrifugal speed and could be applied to in situ GSA analysis, especially at sea.The National Natural Science Foundation of China [40331004]; Ministry of Science and Technology of China [2005DFA20430
阻塞性睡眠呼吸暂停伴认知障碍患者中血清miR-132表达及意义
【目的】探讨miR-132在阻塞性睡眠呼吸暂停(OSA)伴认知障碍患者血清中的表达及其意义。【方法】根据蒙特利尔认知评估(MoCA)评分,将66名年龄在30~60岁之间的阻塞性睡眠呼吸暂停患者分为两组:认知障碍OSA组(OSAI组,n=36)、无认知障碍OSA组(OSAN组,n=30),30名无OSA的成年人作为对照组(HC组,n=30)。对其3组分别进行睡眠测试(OCST)和MoCA评估,并通过PCR检测血清中miR-132的相对表达量。【结果】HC组、OSAI组及OSAN组在年龄、教育程度、性别和高血压方面差异无统计学意义(P>0.05),与OSAN和HC组相比,OSAI组患者血清中miR-132的相对表达水平明显上调(P<0.001),并且与MoCA评分呈正相关(r=-0.726,P<0.001);ROC分析结果显示曲线下面积(AUC)具有统计学意义,具有认知功能障碍(AUC=0.935,95%CI:0.890-0.981,P<0.001)和OSA(AUC=0.787,95%CI:0.695-0.879,P<0.001)。【结论】血清miR-132表达水平升高与OSA的诊断及其认知功能障碍密切相关。血清miR-132的检测有可能成为OSA患者认知功能障碍及诊断的一个潜在指标
Separation and identification of auraptene from grapefruit peel oil
橙油素是广泛存在于柑橘类果实中的天然抗癌活性成分。选用SP70大孔吸附树脂分离纯化葡萄柚精油中的橙油素,该树脂对于橙油素的吸附容量和解吸率分别达到14.53 Mg/g和83.32%,并成功地从树脂床层的洗脱液中结晶分离出橙油素晶体。对所得晶体分别采用差示扫描量热仪(dSC)、紫外吸收光谱(uV)、红外吸收光谱(Ir)、电喷雾质谱(ESI-MS)进行定性分析,分析结果与橙油素标准品相符合。进一步采用高效液相色谱(HPlC)对所得晶体进行定量分析,结果表明所得晶体中橙油素的质量分数可达85%。Auraptene exists widely in the peels and juice sacs of citrus species and is reported to be an effective inhibitor of chemical carcinogenesis in some rodent models.The separation and purification of auraptene from the grapefruit peel oil was performed by SP70 macroporous resin adsorption.The amount adsorbed and the recovery of auraptene were 14.53 mg/g and 83.32% respectively.Auraptene was crystallized out from the concentrated eluate of macroporous resin bed successfully.Differential scanning calorimetric(DSC),ultraviolet spectrum(UV),infrared spectroscopy(IR) and electrospray ionization mass spectroscopy(ESI-MS) were all used to analyze the obtained crystals qualitatively.The analytical results are in accordance with that of auraptene standard.Furthermore,high performance liquid chromatography(HPLC) was utilized to quantify auraptene of the crystals obtained.The mass fraction of auraptene in the obtained crystals can reach 85%.福建省新世纪人才支持项目(0000-X04157
冷战史研究东南亚国家档案导论
20世纪80年代中期到90年代末,可以被视为中国冷战史研究的起步阶段。那时,从事冷战史研究的学者群体偏小,史料来源较为单一(主要利用美国、俄罗斯和中国等国家的档案),关注范围相对狭窄。相比较而言,近二十年中国的冷战史研究明显呈现出整体繁荣的状态。这一点至少体现在如下多个方面:研究队伍不断壮大,而且由于师承关系和科研项目形成了若干或大或小、比较稳定的研究团队;史料挖掘的范围逐渐由美国、俄罗斯和中国扩展到英国、法国、德国、东欧国家、日本、韩国、印度
抗SARS-CoV N蛋白单克隆抗体的特异性及其识别抗原表位的初步鉴定
为了明确抗SARS-CoVN蛋白单克隆抗体的特异性,并鉴定其识别表位,首先在E.coli中表达了人类冠状病毒229E(HCoV-229E)和OC43(HCoV-OC4)N蛋白,用Westernblotting和间接免疫荧光方法分别检测了4株抗SARS-CoVN蛋白单克隆抗体(1-1C2、1-1D6、2-8F11和2-2E5)与HCoV-OC43和HCoV-229E及其N蛋白的交叉反应情况,而后应用12种重组截短型SARS-CoVN蛋白对上述4种单克隆抗体的识别表位进行了初步定位。结果显示:(1)在4株抗N蛋白单克隆抗体中,1-1C2、1-1D6和2-2E5不与HCoV-OC43和HCoV-229E及其N蛋白发生交叉反应,为SARS-CoVN蛋白特异性抗体;(2)2-8F11、1-1D6和2-2E5针对的抗原表位位于SARS-CoVN蛋白的aa30-60,1-1C2针对的抗原表位则位于SARS-CoVN蛋白的aa170-184。这一研究为阐明SARS-CoVN蛋白的免疫学特征,建立特异性免疫诊断技术和研究其致病机制提供了必要的依据和材料
第十八届美国理论与应用力学大会总结
1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学
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