局部对称拟常曲率空间中的紧致子流形

设Nn p是n p 维局部对称完备的拟常曲率黎曼流形.Mn是Nn p中具有平行平均曲率向量的紧致子流形.讨论并给出了这类子流形关于第二基本形式模长平方σ的 Pinching定理.     

单位球面中的伪脐点子流形

本文讨论了单位球面中具有平行平均曲率向量的紧致伪脐点子流形 ,得到了这类子流形的第二基本形式模长平方的一个拼挤定理     

Piper sarmentosum as an antioxidant on oxidative stress in human umbilical vein endothelial cells induced by hydrogen peroxide

Endothelial cell death due to increased reactive oxygen species(ROS) may contribute to the initial endothelial injury,which promotes atherosclerotic lesion formation.Piper sarmentosum(PS),a natural product,has been shown to have an antioxidant property,which is hypothesized to inhibit production of ROS and prevent cell injury.Thus,the present study was designed to determine the effects of PS on the hydrogen peroxide(H2O2)-induced oxidative cell damage in cultured human umbilical vein endothelial cells(HUVECs).In this experiment,HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation(LSGS).HUVECs were treated with various concentrations of H2O2(0-1000 μmol/L) and it was observed that 180 μmol/L H2O2 reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Using the above concentration as the positive control,the H2O2-induced HUVECs were concomitantly treated with various concentrations(100,150,250 and 300 μg/ml) of three different extracts(aqueous,methanol and hexane) of PS.Malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT) and glutathione peroxidase(GPX) levels showed a significant increase(P0.05) in HUVECs compared to the negative control.However,PS extracts showed a protective effect on HUVECs from H2O2-induced cell apoptosis with a significant reduction in MDA,SOD,CAT and GPX levels(P0.05).Furthermore,PS had exhibited ferric reducing antioxidant power with its high phenolic content.Hence,it was concluded that PS plays a beneficial role in reducing oxidative stress in H2O2-induced HUVECs.     

辛空间上可检错Pooling设计的讨论

利用辛空间上全迷向子空间的性质构作了Pooling设计的一种重要的数学模型d-disjunct矩阵并计算了它的Hamming距离,分析了它的检纠错能力,对d的范围作了估算。     

关于局部对称共形平坦黎曼流形中的紧致极小子流形

讨论局部对称共形平坦黎曼流形中的紧致极小子流形,得到了这类子流形第二基本形式模长平方关于外围空间Ricci曲率的Pinching定理,推广了相应的结果。     

可换偏序半群的有限全序扩张

设(S,·,≤)是偏序半群,首先定义了S的半拟序σ及模σ的半拟链,其次,通过模σ的半拟链,将S的偏序≤扩张为≤*,并讨论了(S,·,≤*)是偏序半群的充分条件。最后,还给出了S的满足一定条件的有限子集在≤*下成链的充要条件。     

淮海经济区在新时期的战略选择

区域经济社会协调发展,是国家发展进步追求的目标.淮海经济区作为我国区域经济版图中十分重要且必不可少的重要组成部分,在当前金融危机后的重要发展机遇期,做大做强对我国整体区域经济协调发展将起到重要推动作用.淮海经济区要认清自身优劣势,找准目标定位,在交通、能源等硬件和人才、教育、政策等软件上提升自身,强化体制等方面创新,积极融入全国经济布局,促进区域经济社会又好又快发展.     

具有平行平均曲率向量的伪脐子流形

对于具有平行平均曲率向量的紧致伪脐子流形，推得引理3，从而推广了[1]中的一个相应的结果，另外又给出了一个非常好的由(n，c，H)控制的全脐子流形的一个条件．     

Pinched黎曼流形中具有平行平均曲率向量的闭子流形

研究了完备Pinched黎曼流形N^n P中的具有平行平均曲率向量的闭子流形，获得这类子流形的一般积分不等式以及这类子流形满足α(n，p)(1-c)≤σ≤[n G(n，H，Sn 1)](1-1/3sgn(p-2))-β(n，p)(1-c)的条件下的子流形分布定理，从而把Hong-wei Xu在[3]中关于极小子流形的研究推广到具有平行平均曲率向量的閍子流形的研究．     

局部对称黎曼流形中具常平均曲率的完备超曲面

讨论了局部对称黎曼流形中具常平均曲率的完备超曲面;推广了文献[10]的结果.