三坐标测量机在磁基准中的应用

本文对三坐标测量机（CMM）的用途、基本工作原理、使用工具和方法论以及六级聚焦进行探讨,指出其优势和广阔的应用前景,同时也指出了需要注意的几个方面。     

An integrated microfluidic cell array for apoptosis and proliferation analysis induction of breast cancer cells

In vitro sensitivity testing of tumor cells could rationalize and improve the choice of chemotherapy and hormone therapy. In this report, a microfluidic device made from poly(dimethylsiloxane) and glass was developed for an assay of drug induced cytotoxicity. We evaluated the apoptotic and proliferation-inhibitory effects of anticancer drugs mitomycin C (MMC) and tamoxifen (TAM) using MCF-7 breast cancer cells. MMC and TAM both induced apoptosis and inhibited proliferation of MCF-7 cells in a concentration-dependent manner. MMC caused the expression of antiapoptotic protein Bcl-2 a dose-dependent reduction in MCF-7 cells. The expression of Bcl-2 did not change significantly in MCF-7 cells treated by TAM. The results in the microfluidic device were correlated well with the data obtained from the parallel experiments carried out in the conventional culture plates. The developed microfluidic device could be a potential useful tool for high content screening and high throughput screening research.     

Polyelectrolyte multilayer surface functionalization of poly(dimethylsiloxane) (PDMS) for reduction of yeast cell adhesion in microfluidic devices

Polyelectrolyte multilayers (PEMs) based on the combinations poly(diallyldimethylammonium chloride)∕poly(acrylic acid) (PDADMAC∕PAA) and poly(allylamine hydrochloride)∕PAA (PAH∕PAA) were adsorbed on poly(dimethylsiloxane) (PDMS) and tested for nonspecific surface attachment of hydrophobic yeast cells using a parallel plate flow chamber. A custom-made graft copolymer containing poly(ethylene glycol) (PEG) side chains (PAA-g-PEG) was additionally adsorbed on the PEMs as a terminal layer. A suitable PEM modification effectively decreased the adhesion strength of Saccharomyces cerevisiae DSM 2155 to the channel walls. However, a further decrease in initial cell attachment and adhesion strength was observed after adsorption of PAA-g-PEG copolymer onto PEMs from aqueous solution. The results demonstrate that a facile layer-by-layer surface functionalization from aqueous solutions can be successfully applied to reduce cell adhesion strength of S. cerevisiae by at least two orders of magnitude compared to bare PDMS. Therefore, this method is potentially suitable to promote planktonic growth inside capped PDMS-based microfluidic devices if the PEM deposition is completed by a dynamic flow-through process.     

我们都曾是哭鼻子的小屁孩儿

那时花开,流水芳年。 青春很锋利,很容易就划开记忆的容颜,岁月如梭,稍纵即逝,我们还没来得及回忆青涩和苦涩,感受阵痛和欣喜,时间就呼啸而过了。     

虎年说虎

——现役脑残之王:马布里作为当年96黄金一代的球员之一,马布里如今的生活简直可以用穷困潦倒来形容,自从当年他自称天下第一控卫起,马布里的生涯评定便每况愈下。自此,马布里就开始了与全世界对抗的戏码。最初在森林狼,他就因不满加内特拿到亿元高薪而愤然离开,拆散了一对本该是黄金搭档的组合。在转投纽约后,尽管身为纽约之子,但尼克斯宁可掏出两千万也要请这位大爷走人。自从被尼克斯队抛弃之     

终极娱乐——给魔术师和心灵魔术师的导演笔记（节选）

第二章神秘娱乐的层次关系 从我们的这边看出去,我们带给观众的表演是魔术效果（effect）。而从观众的角度来看呢,我们的演出可分成三种不同的感受：     

Extra-curricular participation in sports and socio-demographic factors in Spanish adolescents: the AVENA study

The aims of this study were to identify differences between the sexes in extra-curricular participation in sports and to determine its association with body fat and socio-demographic factors in Spanish adolescents. A total of 2165 adolescents (1124 males and 1041 females) aged 13.0-18.5 years from the AVENA Study participated. Participants filled in an ad hoc questionnaire for extra-curricular participation in sports, which was the dependent variable. Independent variables were: age, percent body fat, and father's and mother's educational level and occupation. Chi-square tests and logistic regression were applied. Bivariate analysis showed for male adolescents that age and father's occupation were related to extra-curricular participation in sports. In addition, body fat and mother's education and occupation (all P?相似文献   

Effect of countermovement on elbow joint extension power-load characteristics

The aim of the present study was to examine elbow joint extension power-load characteristics with and without a countermovement. Eight male participants performed maximal elbow extensions with and without a countermovement against different loads (0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 kg). Electromyographic activity of the lateral and long heads of the triceps brachii and the biceps brachii muscles was recorded. The average joint power in the concentric phase was significantly enhanced in the countermovement condition at all loads except for 0 kg. The optimal load for the maximal joint power was greater in the countermovement (7.5 kg) than in the no countermovement condition (5.0 kg). Electromyographic activity was unchanged over the intensities and conditions. Our results suggest that the optimal load for the maximal joint power depends on the type of action (i.e. with or without a counter-movement), and that the enhanced joint power in the countermovement condition is due primarily to the storage and utilization of elastic energy.     

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.     

创造奇迹的人

福泽林盖从不相信＂奇迹＂。但在他坚决否认这个世界有奇迹的时候,他发现自己就能创造奇迹。那是一个停电的夜晚,他当时正与他的朋友托德·比米什在一家酒吧喝酒。