Numerical simulation of pulsatile flow in a compliant curved tube model of a coronary artery

The endothelial cells (ECs) lining a blood vessel wall are exposed to both the wall shear stress (WSS) of blood flow and the circumferential strain (CS) of pulsing artery wall motion. These two forces and their interaction are believed to play a role in determining remodeling of the vessel wall and development of arterial disease (atherosclerosis). This study focused on the WSS and CS dynamic behavior in a compliant model of a coronary artery taking into account the curvature of the bending artery and physiological radial wall motion. A three-dimensional finite element model with transient flow and moving boundaries was set up to simulate pulsatile flow with physiological pressure and flow wave forms characteristic of the coronary arteries. The characteristic coronary artery curvature and flow conditions applied to the simulation were: aspect ratio (lambda) = 10, diameter variation (DV) = 6 percent, mean Reynolds number (Re) = 150, and unsteadiness parameter (alpha) = 3. The results show that mean WSS is about 50 percent lower on the inside wall than the outside wall while WSS oscillation is stronger on the inside wall. The stress phase angle (SPA) between CS and WSS, which characterizes the dynamics of the mechanical force pattern applied to the endothelial cell layer, shows that CS and WSS are more out of phase in the coronaries than in any other region of the circulation (-220 deg on the outside wall, -250 deg on the inside wall). This suggests that in addition to WSS, SPA may play a role in localization of coronary atherosclerosis.     

不同转移潜能肿瘤细胞肝素酶的表达

目的研究肝素酶(Heparanase,Hpa)表达水平与人类肿瘤转移的相关性。方法利用半定量RT-PCR、免疫组织化学(S-P法)和Westernblot检测2组4种不同转移潜能的人类肿瘤细胞系中HpamRNA和蛋白的表达水平。结果HpamRNA和蛋白相对表达量在高转移潜能人类肺癌细胞(0·757±0·033,0·670±0·020)、乳腺癌细胞(0·617±0·024,0·661±0·013)中明显高于相应的低转移潜能肺癌细胞(0·518±0·012,0·406±0·012)、乳腺癌细胞(0·170±0·016,0·227±0·011)。结论在所研究的人类肿瘤中,HpamRNA和蛋白的表达水平与肿瘤的转移能力呈正相关。     

中国生物多样性在线数据处理平台的构建

高质量的生物多样性数据能够为生物多样性的研究与保护提供数据支撑。目前研究人员开发了大量的生物多样性数据处理软件或工具, 包括工作流系统、R语言包、Python语言包和Excel工具等, 但是使用这些软件或工具需要用户安装相应的软件客户端, 并掌握一定的编程语言、软件开发和复杂的Excel公式等知识和技能。为降低用户的学习成本和使用门槛, 本文采用了Browser/Server模式设计技术、Web技术、可视化技术、响应式开发技术、网络爬虫技术、数据处理技术和Solr智能检索技术等, 针对不同维度的生物多样性数据设计和开发了相应的数据处理模块, 构建了中国生物多样性在线数据处理平台(http://dp.iflora.cn/)。该平台能够有效地帮助科研人员对物种名称、地理位置、时间日期和经纬度等数据进行处理, 并提供数据格式转换、数据质量评测和资源统计分析等辅助功能, 帮助科研人员实现零代码和低门槛地处理生物多样性数据, 提供便捷、高效和简单的数据清洗、校正、转换和整合等数据处理渠道, 为生物多样性研究和保护提供信息化技术支持与服务。     

油藏嗜热菌与膨润土的相互作用及其对储层防膨的意义

[目的]本文从胜利油田沾3区块的高温油藏的原油采出液中分离得到一株嗜热菌,通过其与膨润土的相互作用,尝试探讨油藏微生物作为油藏储层中水敏性矿物（如蒙皂石）改性剂的可能性。[意义]研究结果将在降低水敏矿物的膨胀性能,为解决水驱采油中遇到的水敏效应的瓶颈问题提供微生物的新途径。[结果]所得菌株为革兰氏阳性菌,呈杆状,具芽孢,兼性厌氧,鉴定为Geobacillus icigianus SL-1。菌株SL-1在厌氧条件下能够还原蒙皂石的结构铁。扫描电镜（SEM）结果显示,无菌对照体系中,蒙皂石呈不规则薄片状。而经微生物作用后,除薄片状蒙皂石外,另有板状次生矿物的生成。进一步能谱（EDS）分析表明,与薄片状蒙皂石相比,板状矿物含有较高的Al/Si比值,且含有明显的K⁺信号。XRD结果显示,经过微生物作用后,固相物质中蒙皂石的百分比下降至47.7%,伊利石百分比上升至29.1%,而无菌对照组中蒙皂石的百分含量则为70.4%,伊利石的百分比则为19.8%。XRD物相分析和EDS结果均证实经过微生物作用后,部分蒙皂石转化成了伊利石。膨胀性能的分析进一步揭示菌株SL-1作用后,矿物膨胀性较初始矿物显著降低,缩膨率达到25.9%。以上结果为油藏储层防膨提供了重要的实验依据。     

A bursal pentapeptide (BPP-I), a novel bursal-derived peptide, exhibits antiproliferation of tumor cell and immunomodulator activity

The bursa of Fabricius (BF) is the central humoral immune organ unique to birds. Here, we isolated a novel bursal pentapeptide I (BPP-I), LGPGP, from BF. BPP-I could play inhibition effect on MCF-7 but not on CEF or Vero cell proliferation in vitro, and enhance antitumor factor p53 protein expression. Also, BPP-I stimulated antibody production in a dose-dependent manner in hybridoma cell. Furthermore, BPP-I could induce various immune responses in mice immunization experiments, including increase antibody production and cytokines IL-4 and IFN-γ level, and induce T-cell immunophenotyping. These results suggest that BPP-I is a potential immunomodulator of antitumor and immunity. The study could provide some novel insights on the probable candidate reagent for the antitumor and immune improvement.     

Structural and functional insights into the role of a cupin superfamily isomerase in the biosynthesis of Choi moiety of aeruginosin

The 2-carboxy-6-hydroxyoctahydroindole (Choi) moiety is a hallmark of aeruginosins, a class of cyanobacterial derived bioactive linear tetrapeptides that possess antithrombotic activity. The biosynthetic pathway of Choi has yet to be resolved. AerE is a cupin superfamily enzyme that was shown to be involved in the biosynthesis of Choi, but its exact role remains unclear. This study reports the functional characterization and structural analyses of AerE. Enzymatic observation reveals that AerE can dramatically accelerate 1,3-allylic isomerization of the non-aromatic decarboxylation product of prephenate, dihydro-4-hydroxyphenylpyruvate (H₂HPP). This olefin isomerization reaction can occur non-enzymatically and is the second step of the biosynthetic pathway from prephenate to Choi. The results of comparative structural analysis and substrate analogue binding geometry analysis combined with the results of mutational studies suggest that AerE employs an induced fit strategy to bind and stabilize the substrate in a particular conformation that is possibly favorable for 1,3-allylic isomerization of H₂HPP through coordinate bonds, hydrogen bonds, π–π conjugation interaction and hydrophobic interactions. All of these interactions are critical for the catalytic efficiency.