Effects of artesunate on membrane surface morphology of human gastric cancer SGC-7901 cells observed under atomic force microscope

AIM: To detect the membrane surface morphology of cancer cells treated with artesunate (ART) under atomic force microscope (AFM). METHODS: Human gastric cancer SGC-7901 cells were cultured and treated with different concentrations of ART for 24 h. The membrane surface morphology, three-dimensional structures and ultrastructural changes of SGC-7901 cells were observed under AFM. The apoptosis of SGC-7901 cells was detected by flow cytometry. RESULTS: The AFM images revealed that the cell nuclear area was full and the surface of cell membrane was flat and smooth in control group. Compared with control group, the cell nuclear area collapsed and suffered atrophy, and the membrane surface had more pores in ART treatment groups. More pores were observed and the diameter of the pores was increased with the increase in ART concentration. The cell membrane ultrastructure showed that the particles in control group had an intensive distribution, some were cord-shaped and some gathered into a mass. The particles in ART treatment groups were fewer and distributed sparsely. Moreover, there were obvious lacunae in the surface of cell membrane. Quantitive measurement found that the height of cell nucleus area was decreased, and the surface root mean square roughness (Rq) and the surface average roughness (Ra) became smaller in ART treatment groups compared with control group. The apoptotic rates of the cells in ART treatment groups were increased with the increase in ART concentration, and were all significantly higher than that in control group. CONCLUSION: Our findings emphasize the significance of AFM in exploring the changes of the membrane surface morphology at nano-scale resolution following the treatment with anticancer drugs, which could not only identify the specific characteristics of morphological changes of the tumor cells, but also provide micromorphological references to reveal the mechanisms of anticancer drugs.     

大直径人工挖孔扩底灌注桩实际应用及效益比较

本文通过对大孔径人工挖孔扩底灌注桩基础与一般钻孔灌注桩基础受力及经济比较,在地质条件合适的情况下,推荐采用大孔径人工挖孔扩底灌注桩基础。     

江西农户庭院经济资源潜力研究——(Ⅰ)农户庭院土地和劳动力潜力研究

通过对京九线江西段１９个沿线县（市、区）１１５８个农户和１６个非沿线县（市、区）８９８个农户庭院经济现状的对比调查结果，推算出江西全省农户庭院面积约为２４万ｈｍ２，占耕地面积１／１０左右；可用于种植业的土地约为１１万ｈｍ２，相当于耕地面积的１／２０左右；剩余劳动力约３００万个，发展潜力很大。     

汽车前后轴制动力分配原理

对汽车在刹车状态下的滑移情况进行了力学分析,并对不同速度下汽车的刹车及前后刹车时间的差异所产生的不同刹车效果进行了分析。     

外商对华投资的正负效应分析

利用统计学的分析方法,分析了我国利用外资的正、负面效应。     

Employment

The 1990s began with unprecedented market conditions for labour: unemployment rates were reaching their highest level in over 50 years, participation in the labour market had fallen to historically low levels and net emigration was widespread across all occupations. It seemed that things could only get better. While some did benefit from the limited growth that took place in the nineties, many did not. The greater inequality generated during the 1980s was fanned by the deregulation of the labour market and remained undiminished throughout the following decade. The marked reduction in manufacturing employment in the 1980s continued into the early 1990s negatively impacting Maori and Pacific Island men and women in particular. Increasingly post‐secondary school education became necessary to gain entry into regular work and those with little formal education and few work skills fell further down the queue. These changes are closely allied to the processes of globalisation which is already exercising considerable influence on the employment opportunities of New Zealanders.     

Evaluation of a simple technique for characterizing rice root systems in relation to drought resistance

Summary Drought is a constraint to rice yields in much of Asia's rainfed rice crop. Although genotypic variation for root system characteristics is well documented in this semiaquatic species, little improvement of rice for drought resistance has been attempted. No simple method to evaluate root systems exists. In this paper we report the development and testing of a simple device to measure the pulling force required to uproot rice seedlings. The force required to pull rice seedlings from the paddy soil was correlated with root weight, root branching and thick root number. The capability to separate rice cultivars by this technique and relationship of the root pulling force to other drought screening methods are illustrated.     

Experimental Study on Moment Modulation of Prestressed Frames

Based on the experimental study of two prestressed frames in redistribution of Internal force, it can be concluded that the dominating influence factors on moment modulation are the relative height of equivalent compression zone, the secondary moment, the ratio of beam rigidity to column and development of cracks in the top of columns.The secondary moment is very important in modulation of frames. Especially, the secondary moment will governing the modulation when the relative height of equivalent compression zone is large enough.     

An Analysis to the Force Property of the Clutch-Screw Press and its Strength Design

This paper deals with the force property analysis,strength design and use of the clutch-screw press.