Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System

The Poisson-Nernst-Planck (PNP) system is a widely accepted model for simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced PNP system, which can well approximate the three dimensional ion channel problem. Positivity of numerical solutions is proven to hold true independent of the size of time steps and the choice of the Poisson solver. The scheme is easy to implement without resorting to any iteration method. Several numerical examples further confirm the positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states.     

甘肃省和政县农村老年性白内障防盲项目的卫生经济学评价研究

目的 对2014-2016年在甘肃省和政县开展的白内障综合防盲干预项目进行卫生经济学评价。设计 横断面调查。 研究对象 甘肃省和政县2014-2016年老年性白内障手术前407例患者及术后半年109例患者。方法 对所有调查对象进行卫生经济学问卷调查。通过净效益法、成本效益分析法和成本效果分析法评价项目产生的经济效益和总成本。主要指标 直接成本、间接成本、直接经济效益、间接经济效益、总成本、总效益、净效益、成本效益比、成本效果比。结果 2014-2016年项目期间甘肃省和政县白内障所致总体疾病经济负担为2142.28万元。白内障手术产生的总效益为3398424.98元，总成本为2939125.20元，净效益为459299.78元，效益成本比为1.16:1。项目每投入1万元可降低50岁以上白内障患者导致的0.027%的致盲率和0.164%致残率；项目每降低1%的50岁以上白内障患者的盲率，需投入36.47万元；每降低1%50岁以上白内障患者的残率，需投入6.11万元。结论 在甘肃省和政县开展的老年性白内障防盲综合干预项目具有较好的产出回报比和较高的防盲技术效率。（眼科，2020，29： 298-303）     

Quality of oral anticoagulation control in Chinese patients with non-valvular atrial fibrillation: a prospective controlled study

Abstract

Objective

The sex, age, medical history, treatment, tobacco use, race risk (SAMe-TT₂R₂) Score; the sex, age, medical history, treatment, tobacco use, genotype combination (SAMe-TT₂G₂) Score; and the so-called modified SAMe-TT₂R₂ scores have been proposed to predict the anticoagulation quality for patients with non-valvular atrial fibrillation (NVAF). The data from a prospective controlled study is used to validate the SAMe-TT₂R₂ and SAMe-TT₂G₂ scores in Chinese NVAF patients treated with warfarin and to evaluate the association of factors with time in therapeutic range (TTR) to predict the quality of oral anticoagulation control.     

Hypocholesterolaemic mechanism of bitter melon aqueous extracts via inhibition of pancreatic cholesterol esterase and reduction of cholesterol micellar solubility

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.     

血清胱抑素C和尿微量白蛋白联合检测在人类免疫缺陷病毒感染者肾功能损伤检测中的应用价值

目的评估血肌酐和尿常规的常规检测基础上联合血清胱抑素C和尿微量白蛋白检测在人类免疫缺陷病毒（HIV）感染者肾功能损伤检测中的应用价值。 方法以2019年2～5月于首都医科大学附属北京地坛医院感染一科住院的169例HIV感染者为研究对象，完善其尿常规、尿微量白蛋白、血肌酐、血清胱抑素C检测；分析尿蛋白及尿微量白蛋白的阳性检出率及其差异，血肌酐升高及血清胱抑素C升高的比例及其差异。计算应用替诺福韦酯（TDF）及合并丙型肝炎、高血压、糖尿病、肿瘤的肾功能损伤的相对危险度。 结果169例HIV感染者中尿常规示尿蛋白阳性者5例（3.0%），尿微量白蛋白升高者17例（10.1%），两者阳性检出率差异具有统计学意义（χ² = 5.9、P = 0.007）。血肌酐升高者10例（5.9%），血清胱抑素C升高者20例（11.8%），两者阳性检出率差异具有统计学意义（χ² = 3.0、P = 0.042）。在尿常规和血肌酐检测的基础上联合检测尿微量白蛋白和血清胱抑素C的总体阳性检出率为49例（30.0%）。CD4⁺ T淋巴细胞计数< 200个/μl与≥ 200个/μl组患者血清胱抑素C水平分别为0.94（0.83，1.05）mg/L、0.85（0.77，0.95）mg/L，差异具有统计学意义（Z =-3.02、P = 0.003）。应用TDF及合并丙型肝炎、高血压、糖尿病、肿瘤的肾功能损伤的相对危险度分别为1.1、1.5、1.9、2.2和1.4。 结论HIV感染者中，单纯以尿常规为依据评估有无蛋白尿，以血肌酐水平为依据评估肾小球滤过功能会低估肾功能损伤的患病率。在常规检测血肌酐和尿常规的基础上联合检测血清胱抑素C和尿微量白蛋白在提高HIV感染者肾功能损伤检出率方面具有重要的应用价值。低CD4⁺ T淋巴细胞计数、应用TDF及合并丙型肝炎、高血压、糖尿病、肿瘤均为肾功能损伤的危险因素。     

Alveolar crest contour changes after guided bone regeneration using different biomaterials: an experimental in vivo investigation

To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects arou