High-Order Positivity-Preserving Well-Balanced Discontinuous Galerkin Methods for Euler Equations with Gravitation on Unstructured Meshes

In this paper, we propose a high-order accurate discontinuous Galerkin (DG) method for the compressible Euler equations under gravitational fields on unstructured meshes. The scheme preserves a general hydrostatic equilibrium state and provably guarantees the positivity of density and pressure at the same time. Comparing with the work on the well-balanced scheme for Euler equations with gravitation on rectangular meshes, the extension to triangular meshes is conceptually plausible but highly nontrivial. We first introduce a special way to recover the equilibrium state and then design a group of novel variables at the interface of two adjacent cells, which plays an important role in the well-balanced and positivity-preserving properties. One main challenge is that the well-balanced schemes may not have the weak positivity property. In order to achieve the well-balanced and positivity-preserving properties simultaneously while maintaining high-order accuracy, we carefully design DG spatial discretization with well-balanced numerical fluxes and suitable source term approximation. For the ideal gas, we prove that the resulting well-balanced scheme, coupled with strong stability preserving time discretizations, satisfies a weak positivity property. A simple existing limiter can be applied to enforce the positivity-preserving property, without losing high-order accuracy and conservation. Extensive one- and two-dimensional numerical examples demonstrate the desired properties of the proposed scheme, as well as its high resolution and robustness.     

中医移动医疗App信息服务现状研究

以“七麦数据”网站收录的中医移动医疗App作为研究对象，采用网络调查法和文献分析法，根据“七麦数据”对移动医疗App的分类，结合中医移动医疗App的信息服务内容和特点，将筛选出的中医移动医疗App划分为医疗健康类、中医养生类、知识传播类、全面综合类，并根据“七麦数据”网站中对各类中医移动医疗App的打分及累计下载量筛选出最具代表性的12款中医移动医疗App，从全面性、人性化、安全性、实用性4个一级指标和40个二级指标对其信息服务现状进行评价，指出当前中医移动医疗App信息服务存在的问题并提出建议。     

宏基因组学测序诊断曼氏裂头蚴病1例

患者于2000年无明显诱因发现下腹部游走性包块，20年来多次就诊，未明确病因。2020年8月11日发现包块游走于左侧腋前，微创手术取出不完整白色虫体3段，用宏基因组学测序鉴定虫体，明确诊断为曼氏裂头蚴病。2021年10月21日经手术取出完整虫体，患者康复出院；随访患者身体状况良好，全身未发现新包块。     

基于生物钟节律探讨前列腺癌的 发病机理及择时治疗策略

生物钟节律观与中医“天人一体”观相契合，生物钟节律紊乱可影响人体的生理病理状态，通过调节生物钟节律可达到提高治疗效果的目的。生物钟节律系统包括中枢生物钟节律系统与外周生物节律系统两大系统，分别在疾病发生发展中发挥不同的作用。与之相应，择时疗法是根据人体气血阴阳节律变化而选择相应药物治疗以达到最佳的疗效的一种时间医学治疗方法。临床上许多前列腺癌患者的发病与生物钟节律紊乱密切相关，通过调整生物钟节律具有预防和改善前列腺癌预后的积极作用。因此，本文将以现代生物钟节律的生理及病理机理为切入点，探讨不同生物钟节律系统紊乱在促前列腺癌中医主证形成过程中的发生机理，进而探讨择时治疗策略在不同类型前列腺癌治疗中运用的可行性，以期对前列腺癌的防治及预后产生一定的影响。     

肝X受体激动剂在肿瘤治疗中的研究进展北大核心

肝X受体(liver X receptors,LXRs)是孤儿核受体转录因子超家族成员,当LXRs被激活后,可调节靶基因的转录表达,不但参与胆固醇、脂肪、糖的代谢以及炎症等过程,并且在许多恶性肿瘤组织中均有表达。为全面了解肝X受体激动剂在治疗癌症中的研究现状,本文将从肝X受体激动剂与胃癌、肝癌、卵巢癌、乳腺癌、子宫内膜癌、肺癌以及结直肠癌的相关性方面进行综述。     

人髌下脂肪垫干细胞的分离培养鉴定及初步研究

目的建立人髌下脂肪垫干细胞分离、培养和鉴定的平台，验证其可作为可靠的干细胞来源，并可作为细胞模型参与科学研究。 方法人髌下脂肪垫取自膝关节置换手术患者，经Ⅰ型胶原酶消化，在高糖Dulbecco改良Eagle培养基(DMEM)内扩增，取P5代细胞用于检测其"干性"及三向分化能力。与微尺度支架结合，通过RT－PCR检测成骨基因的表达，应用最小显著性差异法进行组间两两比较，用于验证微尺度支架的成骨诱导特性。 结果人髌下脂肪垫干细胞具备间充质干细胞相关特性，包括黏附贴壁性；成脂肪、成软骨及成骨分化；表达相关表面标记，如分化抗原簇(CD)73、CD90和CD105；不表达造血细胞系的分子表面标记，如c-kit、CD14、CD11b、CD34、CD45、CD19、CD79和人白细胞抗原(HLA)-DR。本课题中人髌下脂肪垫来源干细胞成功作为一种干细胞模型，证明HaCG微尺度支架具备成骨诱导特性，表现为三组中成骨基因ALP、COL1、Runx2表达差异有统计学意义(分别为F＝150，P<0.01；F＝68，P<0.01；F＝16，P<0.01)。HaCG微尺度支架组高于纯明胶微尺度支架组及二维培养组，纯明胶微尺度支架组高于二维培养组(P值均小于0.05)。 结论人髌下脂肪垫干细胞分离、培养和鉴定平台的建立，未来可作为细胞模型应用于多种不同实验。     

Genetic diversity of porcine circovirus type 2 in China between 1999–2017

Porcine circovirus type 2 (PCV‐2), is linked to PCV‐2 associated disease, which has caused considerable economic loss in the swine industry. Here, we report the genetic diversity of PCV‐2 in China. A total of 74 Chinese PCV‐2 strains sequenced between 1999 and 2017 were studied. Based on the ORF2 and complete genomes, we found that apart from the PCV‐2a, PCV‐2b, and PCV‐2d genotypes, two unstable recombination genotypes also exist, referred to as IM1 and IM2 genotypes. We found that the patterns of PCV‐2 genetic shift in China are similar to the patterns at the global level. Additionally, for the PCV‐2 ORF2 gene of Chinese isolates, we found a similar time to the most recent common ancestor and evolutionary rate to the global values. This indicates that PCV2 genetic diversity in China is driven by genetic drift/recombination of local strains and by the sporadic introduction of foreign genotypes from other countries. Overall, our study illustrates the genetic diversity and evolution dynamics of PCV‐2 in China.