简介:摘要:目前,航空是最快捷的交通工具,随着人们生活水平的不断提高,乘坐飞机也不再是一种奢侈,乘坐飞机出行也被更多的人去选择。为保证飞机的正常运行和进一步改善其安全性,定期的检修与养护是非常必要的关键。A320客机是当前最普遍使用的机型,所以,在空客的维修过程中, C检维修控制点的选择十分重要。以A320空客为例,从 C检控制点的视角,对A320飞机的定检和维修控制进行了较为详细的论述,以期为提高我国航空的飞行安全做出一些努力。
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:摘要目的检测微小RNA-320(miR-320c)在骨关节炎外周血的表达水平,探讨miR-320c的临床意义及在骨关节炎发病机制中的作用。方法收集30例原发性膝骨关节炎、30例结缔组织病患者及同期30例健康对照者的血浆标本,采用荧光定量PCR检测外周血中miR-320c的表达水平。分析其与骨关节炎患者的膝关节严重程度和疼痛评分的相关性。最后转染miR-320c模拟物、miR-320c抑制物及对照物至软骨细胞HC-a,通过CCK-8法检测不同时间点HC-a软骨细胞增殖能力。结果(1)miR-320c在骨关节炎组血浆的表达量(3.26±0.55)明显高于结缔组织病组(1.62±0.50)和健康对照组(1.21±0.66)(F=107.66,P<0.001)。(2)miR-320c的表达水平与骨关节炎患者膝关节影像学的严重程度呈正相关(r=0.830,P<0.001),与疼痛评分尚未发现差异有统计学意义(P>0.05)。(3)与对照组相比,转染miR-320c模拟物组软骨细胞增殖的时点、组间、时点与组别的交互效应差异有统计学意义(F时点=5256.767,F组间=1947.436,F交互=114.314,均P<0.001),增殖水平明显降低。(4)转染miR-320c模拟物组软骨细胞凋亡率明显增高(t=7.85,P<0.01)。结论骨关节炎患者血浆miR-320c表达水平明显升高,且与膝关节影像学的严重程度呈正相关;过表达miR-320c可显著抑制软骨细胞增殖能力,促进凋亡水平。血浆miR-320c可能作为骨关节炎影像学的严重程度的一个预测指标。