简介:摘要:当今电子商务正以迅雷不及掩耳之势影响着世界的各个角落,它改变着消费者的购物观念和方式,特别B2C是模式。而物流配送是实现B2C电子商务快速发展的必须载体,合理的派送不仅能节约成本而且可以促进电子商务的高效流通,成为电子商务真正的依赖。本文介绍了B2C电子商务的主要物流配送模式,对自建物流、第三方物流和混合物流进行了利弊分析,并以京东为例得出了电子商务企业必须根据自身的业务特点,以长远的发展为目标选择最佳的物流配送模式。
简介:摘要目的探讨紫丁香苷对脂多糖(LPS)诱导肌管细胞萎缩的保护作用及其分子机制。方法诱导C2C12成肌细胞分化为肌管细胞后,按随机数字表法分为空白组、模型组、紫丁香苷组。模型组与紫丁香苷组培养基内加入终浓度为200 ng/ml 的LPS进行干预;紫丁香苷组培养基内同时加入10 μmol/L紫丁香苷干预24 h。采用细胞计数(CCK-8)法检测各组细胞活力,Griess试剂检测细胞上清液NO释放量;ELISA法检测上清液TNF-α水平;Western blot法检测NF-κB、过氧化物酶体增殖物激活受体γ1(peroxisome proliferators-activated receptors γ1,PPARγ1)、肌球蛋白重链(myosin heavy chain,MyHC)表达情况。结果与模型组比较,10、100 μmol/L紫丁香苷组细胞增殖率[(101.08±8.92)%、(79.53±5.19)%比(69.07±7.16)%]升高(P<0.01或P<0.05),其中10 μmol/L的紫丁香苷效果更佳。与模型组比较,干预6 h紫丁香苷组NO[(2.92±0.33)μmol/L比(3.57±0.41)μmol/L]水平降低(P<0.01),干预24 h紫丁香苷组细胞TNF-α[(2.73±0.29)pg/ml比(4.15±0.29)pg/ml]水平降低(P<0.01),细胞NF-κB[(0.95±0.24)比(1.16±0.28)]蛋白表达降低(P<0.05),MyHC[(0.79±0.15)比(0.70±0.16)]蛋白表达升高(P<0.05)。结论紫丁香苷可抑制LPS诱发的炎症反应,提高肌管细胞活力,拮抗LPS对肌管细胞的损伤作用。
简介:AbstractBackground:Antiretroviral therapy (ART) has reduced mortality among people living with HIV (PLWH) in China, but co-infections of hepatitis B virus (HBV) and hepatitis C virus (HCV) may individually or jointly reduce the effect of ART. This study aimed to evaluate the impacts of HBV/HCV coinfections on treatment drop-out and mortality among PLWH on ART.Methods:A retrospective cohort study analysis of 58,239 people living with HIV (PLWH) who initiated antiretroviral therapy (ART) during 2010-2018 was conducted in Guangxi Province, China. Data were from the observational database of the National Free Antiretroviral Treatment Program. Cox proportional hazard models were fitted to evaluate the effects of baseline infection of HBV or HCV or both on death and treatment attrition among PLWH.Results:Our study showed high prevalence of HBV (11.5%), HCV (6.6%) and HBV-HCV (1.5%) co-infections. The overall mortality rate and treatment attrition rate was 2.95 [95% confidence interval (CI): 2.88-3.02] and 5.92 (95% CI: 5.82-6.01) per 100 person-years, respectively. Compared with HIV-only patients, HBV-co-infected patients had 42% higher mortality [adjusted hazard ratio (aHR)=1.42; 95% CI 1.32-1.54], HCV-co-infected patients had 65% higher mortality (aHR=1.65; 95% CI: 1.47-1.86), and patients with both HCV and HBV co-infections had 123% higher mortality (aHR=2.23; 95% CI:1.87-2.66).Conclusions:HBV and HCV coinfection may have an additive effect on increasing the risk of all-cause death among PLWH who are on ART. It is suggested that there is need for primary prevention and access to effective hepatitis treatment for PLWH.
简介:摘要:通过借鉴美国顾客满意度模型,构建新的适合测评电商平台满意度的指标模型,并运用层次分析法和模糊综合评价法研究以淘宝网为代表的B2C模式下电商平台顾客满意度。研究表明:消费者对于淘宝网站的满意度整体较为满意,满意度值为3.290。各二级指标从高到低排名依次为感知价格(3.667)、物流配送(3.596)、售后服务(3.354)、在线服务(3.282)、感知质量(2.989)。十个三级指标中大部分指标得分均在3以上,而“产品的质量”和“产品的描述”仅分别为2.985和2.995。基于此,建议淘宝网加强对网站平台产品质量监督,以不断提高顾客满意度。
简介:摘要:介绍了飞机C/C、C/C-SiC飞机刹车材料石墨化度的表征方法、材料石墨化度的影响因素,以及石墨化处理对材料性能的影响,以对工程应用提供指导。
简介:摘要目的探索高糖培养下内皮细胞c-Casitas B谱系淋巴瘤原癌基因蛋白(c-Cbl)表达与活性变化对其成管的影响。方法将人脐静脉内皮细胞(HUVECs)分别以5.5 mmol/L正常浓度葡萄糖(NG)、15.2 mmol/L中等浓度葡萄糖(MG)和25.0 mmol/L高浓度葡萄糖(HG)的培养基处理24 h,采用锁核酸修饰的反义寡核苷酸间隔物(LNA Gapmers)下调c-Cbl表达。蛋白质印迹法(Western blot)检测c-Cbl表达及磷酸化水平。侵袭小室(Transwell)、细胞计数试剂盒(CCK-8)试验检测细胞迁移、增殖能力,成管实验判断细胞的成管能力,并通过t检验评估两组间差异。结果HG组细胞c-Cbl在Y731位点的相对磷酸化水高于NG组(3.27±0.18比1.00±0.19,t=15.140,P<0.01),HG组细胞迁移数低于NG组[(38.33±6.51)个比(180.67±16.17)个,t=-14.147,P<0.01],HG组CCK-8吸光度值低于NG组(0.45±0.05比1.25±0.05,t=-19.596,P<0.01),HG组细胞成管水平低于NG组[相对总长度(0.42±0.08)比(1.00±0.11);相对结节数(0.36±0.07)比(1.00±0.07);相对网眼结构(0.32±0.08)比(1.00±0.10);t=-7.119、-10.870、-9.114,P<0.01]。另外,高糖下调c-Cbl(HG+c-Cbl KD)组CCK-8吸光度值高于高糖对照(HG+NC)组(0.81±0.06比0.46±0.06,t=6.906,P<0.01)、其迁移细胞数也高于HG+NC组[(85.00±9.00)个比(43.67±9.30)个,t=5.534,P<0.01],并且HG+c-Cbl KD组细胞的成管能力高于HG+NC组[相对总长度(0.72±0.05)比(0.42±0.10);相对结节数(0.64±0.08)比(0.33±0.12);相对网眼结构(0.62±0.08)比(0.34±0.08);t=4.874、3.734、4.266,P<0.05]。结论高糖培养下c-Cbl磷酸化激活可抑制血管内皮细胞成管能力。