Association of hypomethylation of LINE-1 repetitive element in blood leukocyte DNA with an increased risk of hepatocellular carcinoma     

Di JZ  Han XD  Gu WY  Wang Y  Zheng Q  Zhang P  Wu HM  Zhu ZZ 《Journal of Zhejiang University. Science. B》2011,12(10):805-811

Global DNA hypomethylation has been associated with increased risk for cancers of the colorectum, bladder, breast, head and neck, and testicular germ cells. The aim of this study was to examine whether global hypomethylation in blood leukocyte DNA is associated with the risk of hepatocellular carcinoma (HCC). A total of 315 HCC cases and 356 age-, sex- and HBsAg status-matched controls were included. Global methylation in blood leukocyte DNA was estimated by analyzing long interspersed element-1 (LINE-1) repeats using bisulfite-polymerase chain reaction (PCR) and pyrosequencing. We observed that the median methylation level in HCC cases (percentage of 5-methylcytosine (5mC)=77.7%) was significantly lower than that in controls (79.5% 5mC) (P=0.004, Wilcoxon rank-sum test). The odds ratios (ORs) of HCC for individuals in the third, second, and first (lowest) quartiles of LINE-1 methylation were 1.1 (95% confidence interval (CI) 0.7–1.8), 1.4 (95% CI 0.8–2.2), and 2.6 (95% CI 1.7–4.1) (P for trend <0.001), respectively, compared to individuals in the fourth (highest) quartile. A 1.9-fold (95% CI 1.4–2.6) increased risk of HCC was observed among individuals with LINE-1 methylation below the median compared to individuals with higher (>median) LINE-1 methylation. Our results demonstrate for the first time that individuals with global hypomethylation measured in LINE-1 repeats in blood leukocyte DNA have an increased risk for HCC. Our data provide the evidence that global hypomethylation detected in the easily obtainable DNA source of blood leukocytes may help identify individuals at risk of HCC.  相似文献   

A semi-implicit three-step method based on SUPG finite element formulation for flow in lid driven cavities with different geometries     

Cheng Huang  Dai Zhou  Yan Bao 《浙江大学学报(A卷英文版)》2011,12(1):33-45

A numerical algorithm using a bilinear or linear finite element and semi-implicit three-step method is presented for the analysis of incompressible viscous fluid problems. The streamline upwind/Petrov-Galerkin (SUPG) stabilization scheme is used for the formulation of the Navier-Stokes equations. For the spatial discretization, the convection term is treated explicitly, while the viscous term is treated implicitly, and for the temporal discretization, a three-step method is employed. The present method is applied to simulate the lid driven cavity problems with different geometries at low and high Reynolds numbers. The results compared with other numerical experiments are found to be feasible and satisfactory.  相似文献   

非线性Klein—Gordon方程各向异性高精度有限元分析     

任金城  郭东林 《咸阳师范专科学校学报》2011,(4):1-4

讨论了在半离散格式下的各向异性双线性元对非线性Klein—Gordon方程的逼近。利用单元自身的特殊性质和一些新的分析技巧得到了超逼近性质,通过构造一个插值后处理算子导出了整体超收敛结果。  相似文献   

原子吸收光谱法测定微量元素研究方法进展     

霍宇平 《吕梁高等专科学校学报》2011,1(2)

原子吸收光谱法作为一种分析方法,在动植物中微量元素的测定方面有其它分析方法不可替代的优点.综述原子吸收光谱法的分类、研究进展,对常见的三种原子吸收光谱法的优缺点进行分析,对其未来的发展方向进行展望,以期对初学者起到一定的指导作用.  相似文献   

随机弱大数定律和弱大教定律的充要条件     

王瑶 《雁北师范学院学报》2011,27(4)

讨论了任意随机变量序列的弱大数定律,得到了随机变量序列分别服从随机弱大数定律和弱大数定律的充要条件,以及独立随机变量序列服从弱大数定律的相关结果。  相似文献   

论《红楼梦》对鲁迅创化“狂人”(“疯子”)文学原型的贡献     

王四四 《甘肃高师学报》2011,16(1):24-25

"狂人"("疯子")是"五四"时期鲁迅创化与激活的最重要的文学原型之一,是多种原型要素的综合。《红楼梦》为其提供了重要的原型要素,它们的重要特征是"疯癫"。  相似文献   

锈蚀钢筋压屈承载力试验研究及有限元分析     

石泉彬  周桂香 《泰州职业技术学院学报》2011,11(5):43-47

在实验室采用直流电源进行电化学加速锈蚀钢筋,从而获得不同直径、长径比和锈蚀率的锈蚀钢筋试件,然后在万能电子试验机上进行压屈试验,获得锈蚀钢筋压屈承栽力曲线。经过统计分析,得到四种形态的锈蚀钢筋压屈承载力计算模型。应用大型有限元分析软件ANSYS对锈蚀钢筋压屈承载力模型进行进一步验证。  相似文献   

一类出现在化学反应器理论中的奇摄动边值问题     

江涛  刘树德 《黄山学院学报》2011,13(5):13-15

研究了一类出现在化学反应器理论中的奇摄动边值问题,在适当的条件下,用合成展开法构造出该问题的形式近似式,并应用微分不等式理论证明了解的存在性及其渐近性质。  相似文献   

随机P-集合及其随机特征     

郭志林 《商丘师范学院学报》2011,27(3):10-15

在P-集合概念的基础上,根据元素迁移的随机性,提出随机P-集合的概念,给出了P-集合的随机生成,P-集合的强随机生成.并根据元素迁移的概率,讨论了随机P-集合的随机特征,给出了随机P-集合的存在背景及在风险投资决策估计中的应用.  相似文献   

试析主宾语可互换句的形成条件     

郭鑫  曾珊 《钦州学院学报》2011,26(5)

主宾语可互换句的形成条件可从动词和名词关系特征方面进行考察,名词多为动作的受事成分及其实现条件,能够进行互换的句子的名词性成分受生命度等级的制约,等级高的容易成为话题,使得主宾语位置互换后句义发生改变。  相似文献