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.     

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.     

Pseudocystic pilomatricoma: A new variant and review of the literature

A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid‐filled sac.     

解剖锁定钢板联合同种异体腓骨治疗肱骨近端骨折疗效的Meta分析

文题释义：肱骨近端骨折：肱骨近端包括肱骨头及大结节、小结节，中老年人骨质疏松及低能量损伤可导致肱骨近端骨折。 同种异体腓骨：取自于人体异体，经过加工处理，去除其免疫原性，保留其骨性结构，可用于移植修复骨缺损，起到支撑作用。 背景：肱骨近端骨折是临床常见骨折，但对肱骨近端内侧柱缺乏支撑的骨折目前仍是治疗难点，并发症常见，失败率较高。 目的：比较解剖锁定钢板联合同种异体腓骨与单纯解剖锁定钢板治疗肱骨近端骨折的疗效。 方法：使用计算机检索PubMed、Embase、Cochrane Library、Google Scholar、中国知网、万方、维普数据库，检索时间均从建库到2020年2月。检索国内外关于对比研究解剖锁定钢板联合同种异体腓骨与单纯解剖锁定钢板治疗肱骨近端骨折疗效的文献。2名研究员根据纳入和排除标准分别独立筛选文献，提取数据，评估文献中的偏倚风险。纳入12篇相关文献使用RevMan 5.2软件将以下指标进行Meta分析，包括影像学数据、功能评分和并发症。结果与结论：①通过文献检索、根据纳入和排除标准，12篇文献纳入研究，其中11篇为回顾性队列研究，1篇为随机对照研究；纳入研究文献质量高，但GRADE证据质量级别较低。②共纳入958例患者，其中解剖锁定钢板联合同种异体腓骨组411例，单纯解剖锁定钢板组547例；③Meta分析结果显示，解剖锁定钢板联合同种异体腓骨组术后1年肱骨头高度差值(MD=-2.40，95%CI：-2.49至-2.31)、颈干角差值(MD= -6.14，95%CI：-6.62至-5.67)、目测类比评分(MD=-0.22，95%CI：-0.35至-0.08)、肩关节功能评分(MD=4.12，95%CI：2.18-6.06)，上肢伤残评分(MD=-10.32，95%CI：-13.44至-7.19)、术后2年的目测类比评分(MD=-0.37，95%CI：-0.55至-0.19)、肩关节功能评分(MD=5.07，95%CI：2.86-7.27)、总体并发症(OR=0.31，95%CI：0.20-0.48)及肱骨头螺钉切出(OR=0.25，95%CI：0.11-0.55)均明显优于单纯解剖锁定钢板组(P < 0.05)，肱骨头坏死(OR=0.94，95%CI：0.47-1.88)，两组间差异无显著性意义(P > 0.05)；④因此，较弱的证据提示，肱骨近端解剖锁定钢板联合同种异体腓骨治疗肱骨近端骨折的短期疗效优于解剖锁定钢板，可减少并发症的发生，促进功能恢复。ORCID: 0000-0002-8486-3932(阳运康) 中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程