Troubled-Cell Indicator Based on Mean Value Property for Hybrid WENO Schemes

In this paper, we introduce a new type of troubled-cell indicator to improve hybrid weighted essentially non-oscillatory (WENO) schemes for solving the hyperbolic conservation laws. The hybrid WENO schemes selectively adopt the high-order linear upwind scheme or the WENO scheme to avoid the local characteristic decompositions and calculations of the nonlinear weights in smooth regions. Therefore, they can reduce computational cost while maintaining non-oscillatory properties in non-smooth regions. Reliable troubled-cell indicators are essential for efficient hybrid WENO methods. Most of troubled-cell indicators require proper parameters to detect discontinuities precisely, but it is very difficult to determine the parameters automatically. We develop a new troubled-cell indicator derived from the mean value theorem that does not require any variable parameters. Additionally, we investigate the characteristics of indicator variable; one of the conserved properties or the entropy is considered as indicator variable. Detailed numerical tests for 1D and 2D Euler equations are conducted to demonstrate the performance of the proposed indicator. The results with the proposed troubled-cell indicator are in good agreement with pure WENO schemes. Also the new indicator has advantages in the computational cost compared with the other indicators.     

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.     

股骨近端空心锁定板内固定治疗股骨颈骨折临床疗效观察

目的：：研究股骨近端空心锁定板内固定治疗股骨颈骨折的临床效果。方法：对2008年2月至2010年4月我院入院治疗的108例股骨颈骨折患者进行了研究，随机分为两组，对照组给与空心钉进行治疗，观察组采用股骨近端空心锁定板内固定治疗，比较两组治疗方案的手术时间、出血量、住院时间以及下床时间，比较两组治疗方案的手术并发症发生率，并比较两组患者三年期临床疗效。结果：观察组患者手术出血量明显少于对照组，手术时间、住院时间以及下床时间明显短于对照组，两组比较差异明显，有统计学意义( P<0.05)；两组患者手术并发症均以疼痛、骨不连以及感染为主，其中观察组上述并发症的发生率为13.0％，明显低于对照组33.3％，两组比较差异有统计学意义( P<0.05)；观察组患者三年临床总有效率为79.6％，对照组患者三年期临床总有效率为51.9％，两组比较差异明显，有统计学意义( P<0.05)。结论：股骨近端空心锁定板内固定治疗股骨颈骨折临床效果显著，可以明显缩短手术时间以及住院时间，降低手术并发症，并且三年临床总有效率更高，值得临床推广应用。     

罗伊氏乳杆菌对轮状病毒感染肠炎患儿免疫功能与肠道菌群及临床疗效的影响

目的探究罗伊氏乳杆菌DSM 17938在治疗轮状病毒感染肠炎患儿中的疗效及对免疫功能、肠道菌群的影响。方法收集于2018年2月-2019年2月在阳光融和医院进行诊治的轮状病毒感染肠炎患儿126例,随机分为试验组(63例)和对照组(63例)。对照组给予常规补液治疗及蒙脱石散和枯草杆菌二联活菌口服治疗,试验组采用常规补液治疗及蒙脱石散和罗伊氏乳杆菌DSM 17938辅助治疗。观察两组患儿的腹泻改善情况,并分析对免疫功能(IgG、IgA、CD4^+/CD8^+水平)及肠道菌群失调的影响。结果在治疗72 h后,试验组患儿的治疗总有效率为92.06%,高于对照组的74.60%(P=0.009);且治疗后两组患儿的IgG、IgA、CD4^+/CD8^+水平均较治疗前有升高(P<0.05),且试验组水平高于对照组(P<0.05)。对患儿肠道菌群进行分析,在治疗1周后,试验组患儿肠道菌群失调程度低于对照组,且试验组的肠道菌群正常比例高于对照组(P<0.05)。结论罗伊氏乳杆菌DSM 17938对于辅助治疗轮状病毒感染肠炎患儿具有良好的疗效,能够提高患儿免疫力,改善肠道菌群失调,减轻患儿腹泻症状,具有一定的临床应用价值。     

Effect of a Device-Free Compressed Shell Fixation Method on Hepatic Respiratory Movement: Analysis for Respiratory Amplitude of the Liver and Internal Motions of a Fiducial Marker

Purpose

Suppression of respiratory movement of the liver would be desirable for high-precision radiation therapy for liver tumors. We aimed to investigate the effect of our original device-free compressed shell fixation method and breathing instruction on suppression of respiratory movement. The characteristics of liver motion based on the movement of a fiducial marker were also analyzed.