早期肠内营养支持对胃癌术后患者肠黏膜屏障功能保护的研究进展

胃癌患者在手术应激状况下，内脏血流减少，肠黏膜处于低灌注状态，易发生肠黏膜损伤。此外，手术刺激可导致肠黏膜充血、水肿、糜烂，加重肠黏膜损伤。近年来，肠内营养被作为保护肠黏膜屏障功能的有效手段。早期肠内营养在肠黏膜屏障功能保护中的作用机制已被证实，然而不同研究结果有一定差异。本研究综述了国内外有关胃癌术后患者行早期肠内营养支持的相关研究，整理、分析既往研究的结论和争议，为早期肠内营养支持的推广应用提供参考。     

Risk factors related to the severity of COVID-19 in Wuhan

Objective: To evaluate the characteristics at admission of patients with moderate COVID-19 in Wuhan and to explore risk factors associated with the severe prognosis of the disease for prognostic prediction.Methods: In this retrospective study, moderate and severe disease was defined according to the report of the WHO-China Joint Mission on COVID-19. Clinical characteristics and laboratory findings of 172 patients with laboratory-confirmed moderate COVID-19 were collected when they were admitted to the Cancer Center of Wuhan Union Hospital between February 13, 2020 and February 25, 2020. This cohort was followed to March 14, 2020. The outcomes, being discharged as mild cases or developing into severe cases, were categorized into two groups. The data were compared and analyzed with univariate logistic regression to identify the features that differed significantly between the two groups. Based on machine learning algorithms, a further feature selection procedure was performed to identify the features that can contribute the most to the prediction of disease severity.Results: Of the 172 patients, 112 were discharged as mild cases, and 60 developed into severe cases. Four clinical characteristics and 18 laboratory findings showed significant differences between the two groups in the statistical test (P<0.01) and univariate logistic regression analysis (P<0.01). In the further feature selection procedure, six features were chosen to obtain the best performance in discriminating the two groups with a linear kernel support vector machine. The mean accuracy was 91.38%, with a sensitivity of 0.90 and a specificity of 0.94. The six features included interleukin-6, high-sensitivity cardiac troponin I, procalcitonin, high-sensitivity C-reactive protein, chest distress and calcium level.Conclusions: With the data collected at admission, the combination of one clinical characteristic and five laboratory findings contributed the most to the discrimination between the two groups with a linear kernel support vector machine classifier. These factors may be risk factors that can be used to perform a prognostic prediction regarding the severity of the disease for patients with moderate COVID-19 in the early stage of the disease.     

Design and Properties Analysis of Novel Modified 1-3 Piezoelectric Composite

With the increasing demand for energy exchangers in underwater acoustic equipment, a modified 1-3 piezoelectric composite material is fabricated based on three-component phases. The new material outperforms the traditional two-phase 1-3 structure. Flexible silicone rubber polymer strengthened the piezoelectric composite and the properties of modified 1-3 piezoelectric composite have been tested by method of finite element simulation and experiment, respectively. This modified material has a high electromechanical coupling coefficient; the maximum can reach 0.684 and −3 dB bandwidth is superior to the two-phase 1-3 type. At the same time, the modified phase 1-3 type structure has an excellent decoupling effect. Silicone rubber can reduce the negative coupling vibration of epoxy resin, the vibration model simplification of piezoelectric composite, and the result of the experiment and simulation has good consistency.     

基于维修数据的医用超声设备常见故障与易损部件分析

目的 对超声设备故障现象和易损部件进行分类统计,探讨针对性的超声设备预防性维修维护策略.方法 对2016～2019年间457次超声设备故障进行统计分析,从故障现象、导致该故障现象的易损部件等方面进行分类统计.结果 超声设备高发的故障现象依次为显示故障(34％)、开机故障(23％)、面板故障(16％)和探头故障(11％),高发的易损部件依次为探头(38％)、面板(17％)、电源(12％)、计算机硬件(9％)和板卡(8％),且进口设备与国产设备之间、台式设备与便携式设备之间的高发易损部件存在差异;进口设备高发易损部件依次为探头(37％)、面板(18％)和电源(13％),国产设备高发易损部件依次为探头(40％)、软件(21％)和面板(12％);台式设备高发易损部件依次为探头(42％)、面板(20％)和计算机硬件(9％),便携式设备高发易损部件为电源(34％)、探头(22％)和计算机硬件(8％).结论 超声设备高发的易损部件主要为探头、面板、电源、计算机硬件和板卡,且进口设备与国产设备之间、台式设备与便携式设备之间的高发易损部件存在差异,对超声设备的预防性维修维护应主要针对这些高发易损部件展开,同时应根据设备之间的差异具有针对性.     

负荷渐增式训练对老年小鼠骨骼肌卫星细胞AMPK磷酸化的影响

目的 探讨负荷渐增式训练对老年小鼠骨骼肌卫星细胞腺苷酸活化蛋白激酶（AMP-activated protein kinase，AMPK）磷酸化的影响。方法 实验小鼠分为 3 组：青年对照组（YC组，n=12）、老年对照组（OC组，n=12）与老年运动组（OT组，n=12）。OT组进行负荷渐增式训练，流式细胞分选技术分离CD45-/CD31-/Sca1-/VCAM(CD106)+细胞群体，分选细胞通过desmin、Myod肌原性染色以及成肌分化诱导培养进行肌卫星细胞鉴定，免疫组化结合Western blotting方法检测肌卫星细胞p-AMPK水平。结果 YC组骨骼肌卫星细胞AMPK及p-AMPK表达水平显著高于OC组（P<0.05）；OT组与OC组AMPK表达无明显变化（Ｐ>0.05），而OT组p-AMPK表达水平显著高于OC组（P<0.05）。结论 负荷渐增式训练可促进老年小鼠骨骼肌卫星细胞AMPK磷酸化，改善老年小鼠骨骼肌能量代谢。