中国老年性病发病趋势及临床特点

人口老龄化的背景下,老年性病发病占比增加,梅毒、艾滋病等危害性较高的疾病增长速度较快,值得引起关注。男性、老年、农村环境等因素成为老年性病高发的标签,高危性行为仍然是发病的主要原因,现对国内老年性病的发病趋势及临床特点作如下综述。

多气源天然气管网运行优化问题的混合整数规划模型及其算法

对于多气源天然气管网运行优化问题,文章首先引入了刻画压缩机开关的0-1整数变量,并对非线性的管道压降方程进行了合理的松弛化处理,建立了更符合实际的非线性混合整数规划模型.其次,基于序列线性化的思想,设计了一种求解该模型的序列混合整数线性化算法.最后,在不同规模的天然气管网系统中进行了多方面的对比实验.实验结果表明,新模型及求解算法能够有效降低成本、减少压缩机能耗,并且所需求解时间大大减少.

A Barzilai-Borwein conjugate gradient method

The linear conjugate gradient method is an optimal method for convex quadratic minimization due to the Krylov subspace minimization property. The proposition of limited-memory BFGS method and Barzilai-Borwein gradient method, however, heavily restricted the use of conjugate gradient method for largescale nonlinear optimization. This is, to the great extent, due to the requirement of a relatively exact line search at each iteration and the loss of conjugacy property of the search directions in various occasions. On the contrary, the limited-memory BFGS method and the Barzilai-Bowein gradient method share the so-called asymptotical one stepsize per line-search property, namely, the trial stepsize in the method will asymptotically be accepted by the line search when the iteration is close to the solution. This paper will focus on the analysis of the subspace minimization conjugate gradient method by Yuan and Stoer(1995). Specifically, if choosing the parameter in the method by combining the Barzilai-Borwein idea, we will be able to provide some efficient Barzilai-Borwein conjugate gradient(BBCG) methods. The initial numerical experiments show that one of the variants, BBCG3, is specially efficient among many others without line searches. This variant of the BBCG method might enjoy the asymptotical one stepsize per line-search property and become a strong candidate for large-scale nonlinear optimization.

An improved nonlinear conjugate gradient method with an optimal property

Conjugate gradient methods have played a special role in solving large scale nonlinear problems. Recently, the author and Dai proposed an efficient nonlinear conjugate gradient method called CGOPT, through seeking the conjugate gradient direction closest to the direction of the scaled memoryless BFGS method. In this paper, we make use of two types of modified secant equations to improve CGOPT method. Under some assumptions, the improved methods are showed to be globally convergent. Numerical results are also reported.

梅毒螺旋体对巨噬细胞极化的诱导作用

目的探究巨噬细胞对梅毒螺旋体(Tp)的吞噬作用及Tp刺激后巨噬细胞的极化方向。方法用Tp Nichols株作用人单核细胞THP-1来源的M0型巨噬细胞后,通过透射电镜和免疫荧光染色观察巨噬细胞对Tp的吞噬作用及巨噬细胞内结构的变化。Tp作用M0型巨噬细胞12 h后,继续培养24 h、48 h、72 h和6 d,分别通过Western印迹、免疫荧光染色观察M1型巨噬细胞表面标记CD86、M2型巨噬细胞表面标记CD163的表达,酶联免疫吸附试验检测巨噬细胞培养上清液中M1型细胞因子白细胞介素(IL)-12 p70、干扰素γ、趋化因子配体10、IL-6、肿瘤坏死因子α和IL-1β水平,以及M2型细胞因子转化生长因子β1(TGF-β1)水平。采用Dunnett-t检验进行组间数据比较。结果透射电镜观察发现,Tp刺激巨噬细胞后,巨噬细胞伸出伪足将Tp吞噬进细胞内,引起内质网肿胀、明显不规则增生和线粒体体积增大。而且,Tp刺激巨噬细胞后,继续培养24 h、48 h、72 h及6 d后巨噬细胞均高表达CD86,但低表达CD163,且24 h时上清液中IL-12 p70、干扰素γ、趋化因子配体10、IL-6、肿瘤坏死因子α和IL-1β均高于对照组(均P<0.001),但TGF-β1与对照组差异无统计学意义(P>0.05)。结论THP-1来源的巨噬细胞吞噬Tp后内质网、线粒体结构发生变化;Tp可诱导M0型巨噬细胞极化为M1型巨噬细胞,且在6 d内不发生M1/M2型巨噬细胞再转化。