弯道水流紊动强度

采用先进的三维声学多普勒流速仪对水力光滑壁面的弯道水流紊动特性进行了系统的试验研究 ,较为全面地测量了弯道水流的三维时均流速和脉动强度等 .根据试验数据 ,探讨了弯道水流的紊动机理 ,分析了弯道水流的紊动特性 ,得出了弯道水流纵向相对紊动强度的数学表达式 ;同时还对弯道水流纵向、横向及垂向的紊动强度分布特点进行了比较 .     

Effect of hypoxia on human adipose-derived mesenchymal stem cells and its potential clinical applications

Human adipose-derived mesenchymal stem cells (hASCs) are an ideal cell source for regenerative medicine due to their capabilities of multipotency and the readily accessibility of adipose tissue. They have been found residing in a relatively low oxygen tension microenvironment in the body, but the physiological condition has been overlooked in most studies. In light of the escalating need for culturing hASCs under their physiological condition, this review summarizes the most recent advances in the hypoxia effect on hASCs. We first highlight the advantages of using hASCs in regenerative medicine and discuss the influence of hypoxia on the phenotype and functionality of hASCs in terms of viability, stemness, proliferation, differentiation, soluble factor secretion, and biosafety. We provide a glimpse of the possible cellular mechanism that involved under hypoxia and discuss the potential clinical applications. We then highlight the existing challenges and discuss the future perspective on the use of hypoxic-treated hASCs.     

两阶段模糊c-均值聚类算法及其应用

针对模糊c-均值算法对初始值敏感、收敛结果易陷入局部极小值的缺点,提出了两阶段模糊c-均值聚类算法.首先通过恰当的贴近度(满足相似相近性)估计分类数,选取初始聚类中心;然后通过模糊c-均值算法进行聚类,最后对所得的聚类中心采用逻辑斯谛型的灰色模型进行预测.由于聚类中心具有统计特征,因此较好地克服了样本间的随机误差,灰色逻辑斯谛模型较好地克服了每个样本内误差.采用上述方法对全国30个省市农村居民年收入进行了分析和比较,得出了具有参考价值的结果.     

燃气轮机齿轮耦合转子系统的动力学特性

在考虑滑动轴承的基础上,利用传递矩阵法分别建立了两单轴转子的弯曲振动分析模型,推导了人字齿轮耦合单元的传递矩阵,应用整体传递矩阵法建立了人字齿轮转子系统的弯扭耦合振动分析模型,对某燃气轮机齿轮-转子-轴承系统进行了振动特性分析。通过数值计算与分析,获得齿轮转子系统的特征值、对数衰减率及临界转速。结果表明该齿轮-转子-轴承系统的工作转速远离临界转速,具有工作的稳定性和安全性。     

白藜芦醇抑制HeLa细胞肿瘤活性的自由基机理

白藜芦醇是一种植物抗毒素,属多元酚类。虽然迄今的研究表明,白藜芦醇能有效抑制许多癌细胞的肿瘤活性,但均未从自由基生物角度来阐明其抑制肿瘤活性的机理。该研究以离体HeLa细胞为材料,利用细胞培养法研究了白藜芦醇抗肿瘤活性的功效,以及产生这种功效的自由基途径,旨在从自由基生物学的角度进一步揭示白藜芦醇抗肿瘤活性的机量。噻唑蓝法及流式细胞仪分析结果表明,白藜芦醇能强烈抑制HeLa细胞增殖阻断HeLa细胞由S期向G2期转变。HeLa细胞内源性活性氧（ROS）及HeLa细胞内部氧化还原态的实验结果表明,白藜芦醇对细胞自分泌的总ROS有一定的抑制作用,它抑制HeLa细胞自分泌的O^-2浓度与抑制HeLa细胞增殖之间有明显的相关关系;同时,白藜芦醇可明显增高HeLa细胞内源SOD的活性以及GSH的含量,但可使CAT的活性显著下降,提示白藜芦醇能显著改变细胞内部的氧化还原态。以上结果为白藜芦醇抗癌机制提供了自由基生物学方面的实验依据。     

SCF(FBW7) regulates cellular apoptosis by targeting MCL1 for ubiquitylation and destruction

The effective use of targeted therapy is highly dependent on the identification of responder patient populations. Loss of FBW7, which encodes a tumour-suppressor protein, is frequently found in various types of human cancer, including breast cancer, colon cancer and T-cell acute lymphoblastic leukaemia (T-ALL). In line with these genomic data, engineered deletion of Fbw7 in mouse T cells results in T-ALL, validating FBW7 as a T-ALL tumour suppressor. Determining the precise molecular mechanisms by which FBW7 exerts antitumour activity is an area of intensive investigation. These mechanisms are thought to relate in part to FBW7-mediated destruction of key proteins relevant to cancer, including Jun, Myc, cyclin E and notch 1 (ref. 9), all of which have oncoprotein activity and are overexpressed in various human cancers, including leukaemia. In addition to accelerating cell growth, overexpression of Jun, Myc or notch 1 can also induce programmed cell death. Thus, considerable uncertainty surrounds how FBW7-deficient cells evade cell death in the setting of upregulated Jun, Myc and/or notch 1. Here we show that the E3 ubiquitin ligase SCF(FBW7) (a SKP1-cullin-1-F-box complex that contains FBW7 as the F-box protein) governs cellular apoptosis by targeting MCL1, a pro-survival BCL2 family member, for ubiquitylation and destruction in a manner that depends on phosphorylation by glycogen synthase kinase 3. Human T-ALL cell lines showed a close relationship between FBW7 loss and MCL1 overexpression. Correspondingly, T-ALL cell lines with defective FBW7 are particularly sensitive to the multi-kinase inhibitor sorafenib but resistant to the BCL2 antagonist ABT-737. On the genetic level, FBW7 reconstitution or MCL1 depletion restores sensitivity to ABT-737, establishing MCL1 as a therapeutically relevant bypass survival mechanism that enables FBW7-deficient cells to evade apoptosis. Therefore, our work provides insight into the molecular mechanism of direct tumour suppression by FBW7 and has implications for the targeted treatment of patients with FBW7-deficient T-ALL.     

一类不确定T-S非线性时滞系统的镇定研究

研究了一类不确定T-S非线性时滞系统的稳定性分析与镇定问题.通过构造新的模糊权依赖型Lyapunov泛函,引用自由权矩阵和二重积分,以线性矩阵不等式的形式给出了不确定非线性时滞系统的稳定和镇定的充分条件,最后以仿真例子说明了所提方法的有效性.     

GPS动态定位的强跟踪卡尔曼滤波研究

提出一种改进的强跟踪卡尔曼滤波算法，应用于ＧＰＳ动态定位滤中获得明显效果，首先采用描述机动载体运动的“当前”统计模型，建立了一咱新的ＧＰＳ动态定位扩展卡尔曼滤波模拟及其适应算法，然后，为了进一步提高滤波器的动态性能，改进了周东华等提出了的强跟踪滤波器，大大提高了ＧＰＳ动态定位位扩展卡尔曼滤器的跟踪能力。     

猕猴桃种间体细胞杂种的抗寒性遗传的初步分析

中华猕猴桃（Actinitia chinesis）与狗枣猕猴桃（A.kolomidta）各间体细胞杂种无性系试管苗叶片在20,10,4,0和－15℃温度处理理,叶片细胞的电导率、脯氨酸质量分数ω和丙二醛质量摩尔浓度b具有不同的变化,结合叶片厚度测量数据,进行聚类分析的结果表明：种间体细胞杂种无性系CK6和CK13的抗寒性弱,趋向于中华猕猴桃;而无性系CK11和CK8的抗寒性强,趋向于狗枣猕猴桃。     

石斑鱼增殖放流研究

使用体外挂标志牌和体内注射着色液（入墨法）方法对赤点石斑鱼Epinephelus akaara和青石斑鱼Epinephelusawoara幼鱼（人工培育幼鱼和野生幼鱼）和野生成鱼进行标志放流试验。结果表明：石斑鱼幼鱼和成鱼移动范围不大，幼鱼最长经651d、成鱼最长经48d的移动均在2n mile以内，其栖息习性均具有明显的地域性。挂牌标志法只获得放流当年重捕记录，入墨法获得当年、第二年和第三年的重捕记录，室内水泥池暂养标志鱼有1／3标志牌脱落，说明体外挂牌标志对石斑鱼不太适合。放流入墨法标志幼鱼各水域重捕率第一年1.4%-4.5%、第二年3.1%-13.4%、第三年0.7%。此标志法对研究群体生长较理想。