Mechanism of the interaction between Au nanoparticles and polymerase in nanoparticle PCR

Nanoparticle PCR is a novel method to optimize DNA amplification. It performs well in improving specificity, enhancing sensitivity and speed. Several mechanisms were proposed in previous studies: one was based on the interaction between gold nanoparticles (AuNPs) and DNA while the other was attributed to the heat transfer property of AuNPs. In this paper, we propose that the interaction between AuNPs and DNA polymerase can significantly influence PCR. First, the addition of DNA polymerase can eliminate the inhibitory effects of excess AuNPs. Second, the addition of AuNPs will increase yield of the desired PCR product and make the optimum concentration of DNA polymerase move to higher value. Third, while excess polymerase might inhibit amplification efficiency, AuNPs can reverse this process and the yield of PCR amplification. Based on these results we propose a possible mechanism that AuNPs might modulate the activity of polymerase and improve PCR amplification.     

The use of electro-deoxidation in molten salts to reduce the energy consumption of solar grade silicon and increase the output of PV solar cells

Solar photovoltaics, based upon silicon, are the most popular form of solar cell with efficiencies around 20%. These efficiencies can be further increased by employing light trapping schemes to minimise optical losses through scattering and reflection which enhances the amount of light absorbed and number of photo-carriers generated. Typical approaches employ antireflection coatings (ARCs) or texturise the surface of the silicon disks, so that the structure consists of an array of needles which can absorb most of the light. Usually, these structures are created by leaching the silicon with hydrofluoric-based acids or by reactive ion etching (RIE) methods. This paper reviews some of the methods for improving the energy efficiency of silicon production, and describes the use of electro-deoxidation of SiO2 layers, on silicon, in molten calcium chloride to form nano-porous black silicon (b-Si) structures. By coating b-Si surface with TiO2, a common ARC, extremely black surfaces with negligible reflectance of about 0.1%, are produced, which can have applications for low-cost high efficiency solar cells.     

Polaron-pair-dependent equivalent circuit parameters of organic solar cells based on CuPc and C<Subscript>60</Subscript>

We present the current-voltage characteristics of organic solar cells based on single and double heterojunction of copper phthalocyanine (CuPc) and C60 by introducing a constant JP instead of photo-current density Jph to represent the density of polaron-pairs generated from excitons at D/A interface. A diode Dext models polaron-pair dissociation, and a diode Drec stands for loss due to polaron-pair recombination. The photovoltaic response under AM 1.5 solar illumination at an intensity of 100 mW/cm2 is para...     

黄河兰州段水体中有机污染物对MCF-7细胞凋亡的影响及其机制

采用固相萃取法提取黄河兰州段中山桥(污染断面)、什川桥(自净断面)和新城桥(清洁断面)三个断面水样中有机污染物,用流式细胞仪和激光共聚焦显微镜检测不同断面有机污染物对MCF-7细胞染毒后的周期分布、细胞凋亡率和细胞内游离[Ca2+]i的浓度,探讨水体中有机污染物的细胞毒性作用机制及其与细胞凋亡的关系.结果表明:染毒48 h,各断面MCF-7细胞的凋亡率由高到低依次为中山桥组(31.40±3.00)％、新城桥组(17.63±0.47)％、什川桥组(13.37±1.43)％,均显著高于对照组(8.1±0.25)％(P＜0.01);各组细胞主峰均在G0/G1期积聚(≥55％),说明有机污染物主要作用于细胞的G0/G1期,使细胞停滞于此期.各断面各剂量组有机污染物分别作用于MCF-7细胞24,48,72 h后,在不同时点细胞内[Ca2+]i浓度均升高,均显著高于对照组(P＜0.01);各组细胞内[Ca2+]i浓度随染毒时间的延长呈下降趋势,具有时间效应关系;在不同时点上无钙离子组和含钙离子组间均有显著性差异(P＜0.05),提示钙离子浓度增加与外钙无关.研究表明,黄河兰州段水体中有机污染物可影响体外MCF-7细胞的周期分布并诱导细胞凋亡,其作用机制还需进一步探讨.     

氯化锂对MGC803细胞增殖及细胞周期的影响

研究氯化锂(LiCl)在体外对MGC803胃癌细胞增殖及周期的影响,以不同浓度的LiCl作用MGC803细胞24 h后,采用四甲基偶氮唑盐(MTT)比色法检测各组细胞的增殖活性,利用流式细胞术进行细胞周期分析.结果:①不同浓度的LiCl(10、20、40 mmol/L)均对MGC803细胞具有抑制增殖的作用,这种增殖抑制作用呈剂量依赖关系.②随着LiCl浓度的升高,发生G2/M期阻滞,与正常对照组相比,差异具统计学意义.说明LiCl能抑制MGC803胃癌细胞增殖和导致G2/M期阻滞.     

p-i-n型非晶硅薄膜电池p层材料制备及光学性能研究

采用射频等离子体增强化学气相沉积(RF-PECVD)方法制备非化学计量比氢化非晶碳化硅(a-SiC:H)薄膜材料,借助紫外可见(UV-Vis)光谱、激光拉曼(Raman)光谱和傅里叶变换红外(FTIR)光谱等手段,研究了p-i-n型非晶硅(a-Si:H)薄膜太阳能电池p层a-SiC:H薄膜材料的制备与光学性能.研究结果表明甲烷和硅烷掺杂比能影响a-Si:H薄膜成键情况,而射频功率一定程度上能影响薄膜沉积速率,该研究结果可为制备转换效率高、性能稳定的p-i-n型非晶硅薄膜太阳能电池提供支持.     

佛手挥发油对B16细胞增殖及其酪氨酸酶活性的影响

为检测佛手挥发油对B16黑色素瘤细胞增殖及其酪氨酸酶活性的影响,采用台盼蓝排斥法测定了细胞存活率、瑞-姬氏混染法观察了细胞形态变化、吖啶橙/溴化乙锭染色法检测了细胞的凋亡与坏死,用酶学方法测定了细胞中酪氨酸酶活性.结果表明:佛手挥发油对B16黑色素瘤细胞增殖具有显著的抑制作用,呈剂量依赖性;62.50,125.00和250.00μg.mL-1佛手挥发油处理细胞6 h后,细胞核染色质凝聚于核膜内侧,呈固缩状或圆珠状,表现为典型的细胞凋亡特征;500.00μg.mL-1佛手挥发油处理细胞后,细胞膜破裂,出现细胞碎片,说明细胞已经坏死.酪氨酸酶活性检测结果显示:佛手挥发油对B16黑色素瘤细胞酪氨酸酶活性具有明显的抑制作用,且呈剂量依赖性.     

HCAP1基因对Raji细胞凋亡及凋亡相关蛋白Bax/Bcl - 2的作用

目的：研究外源HCAP1基因产物对Burkitt淋巴瘤细胞系Raji细胞凋亡及凋亡相关蛋白Bax／Bcl-2的作用。方法：用脂质体介导的基因转移方法，把外源HCAP1基因转染到Raji细胞中，用流式细胞术和Hochest 33258荧光染色检测细胞凋亡；用Western blot检测外源HCAP1基因对凋亡相关蛋白Bax和Bcl-2蛋白表达的调节。结果：外源HCAPl基因导入Raji细胞24、48和96h后，细胞凋亡率增加。Western blot显示Bax／Bel-2蛋白表达比值明显增高。结论：转染外源性HCAP1基因可诱导Raji细胞凋亡，使Bax／Bcl-2蛋白表达比例上调可能是HCAP1诱导凋亡的机制之一。     

Effects of enhancing p21 waf1 on proliferation and expression of G1cyclins andCDKs in human breast cancer cells

The cyclin-dependent kinase inhibitor p21( waf1/cip1/sdil) is an important negative regulator in control of cell cycle. Its functions of inhibiting cancer cell growth and its effects on expression of G1 phase cyclins and related CDKs are a worthy topic for study. The plasmid expressing p2l with high level was transformed to human breast cancer cells, and the expression of p2l in cells was enhanced, then the cell growth rate, anchorage-independent growth and tu-morigenecity were tested, at the same time the expression levels of cyclinD1, CDK4, cyclinE and CDK2 were analyzed by Northern blot. The results showed that since the expression of p21 was enhanced in the cell, the rate of cell growth and anchorage-independent growth was inhibited, tumorigenecity was suppressed, the level of expression of cyclinE and CDK2 decreased while that of cyclinDl and CDK4 was not affected. It is suggested that the enhanced expression of p21 markedly inhibits the proliferation and lessens the tumorigenecity of breast cancer cells, and that p2l expression is not related to that of cyclinDl and CDK4, but affects the expression of cyclinE and CDK2 .     

Effects of blocking LeY oligosaccharide on cell surface to MMPs secreted by blastocysts and epithelial cells in mousein vitro

In order to understand the role of Le+Y oligosaccharide antigen (Le+Y) during implantation, the relationship of Le+Y on the cell surface with matrix metalloproteinase (MMPs) secreted by blastocysts and monolayer epithelial cells during implantation in the mouse %in vitro% was studied by monoclonal antibody (mAb) AH-6, directed to Le+Y[Fuc α1-2 Gal β1-4 (Fuc α1-3) GlcNAc-], and gelatin zymography. The results showed that MMPs secretion was reduced after Le+Y on the cell surface of either epithelial cells or trophoblasts was blocked. It indicated that MMPs expression which played an important function during the process of implantation were regulated by Le+Y. Therefore, it was considered that Le+Y could regulate embryos invasion by some mechanism.