A self-contained polymeric cartridge for automated biological sample preparation

Sample preparation is one of the most crucial processes for nucleic acids based disease diagnosis. Several steps are required for nucleic acids extraction, impurity washes, and DNA/RNA elution. Careful sample preparation is vital to the obtaining of reliable diagnosis, especially with low copies of pathogens and cells. This paper describes a low-cost, disposable lab cartridge for automatic sample preparation, which is capable of handling flexible sample volumes of 10 μl to 1 ml. This plastic cartridge contains all the necessary reagents for pathogen and cell lysis, DNA/RNA extraction, impurity washes, DNA/RNA elution and waste processing in a completely sealed cartridge. The entire sample preparation processes are automatically conducted within the cartridge on a desktop unit using a pneumatic fluid manipulation approach. Reagents transportation is achieved with a combination of push and pull forces (with compressed air and vacuum, respectively), which are connected to the pneumatic inlets at the bottom of the cartridge. These pneumatic forces are regulated by pinch valve manifold and two pneumatic syringe pumps within the desktop unit. The performance of this pneumatic reagent delivery method was examined. We have demonstrated the capability of the on-cartridge RNA extraction and cancer-specific gene amplification from 10 copies of MCF-7 breast cancer cells. The on-cartridge DNA recovery efficiency was 54-63%, which was comparable to or better than the conventional manual approach using silica spin column. The lab cartridge would be suitable for integration with lab-chip real-time polymerase chain reaction devices in providing a portable system for decentralized disease diagnosis.     

Sealing SU-8 microfluidic channels using PDMS

A simple method of irreversibly sealing SU-8 microfluidic channels using PDMS is reported in this paper. The method is based on inducing a chemical reaction between PDMS and SU-8 by first generating amino groups on PDMS surface using N₂ plasma treatment, then allowing the amino groups to react with the residual epoxy groups on SU-8 surface at an elevated temperature. The N₂ plasma treatment of PDMS can be conducted using an ordinary plasma chamber and high purity N₂, while the residual epoxy groups on SU-8 surface can be preserved by post-exposure baking SU-8 at a temperature no higher than 95 °C. The resultant chemical bonding between PDMS and SU-8 using the method create an interface that can withstand a stress that is greater than the bulk strength of PDMS. The bond is permanent and is long-term resistant to water. The method was applied in fabricating SU-8 microfluidi-photonic integrated devices, and the obtained devices were tested to show desirable performance.     

再现古印第安社会

人类历史只有一小段有文字记录。文字出现之前的人类历史，只能依赖考古证据。考古学者研究废墟、人工制品、人类骨骸，费尽心力。重建了一千年前、甚至几百万年前的人类社会风貌。不过，要想弄清楚几类社会的形成和变迁过程，更为困难。400万年前，我们的祖先不会制造石器，也没什么交谈能力，只不过是以直立体态行走的灵长类罢了；他们结群生活．但是每个队群的人数部不多。     

产业用纺织品用途的扩展

当我们讨论产业用纺织品在可充气产品领域的用途时,大多数人比较熟悉的一种用途是用于“比空气轻的”飞艇(“lighter-than-air”craft),比如热气球、软式飞艇和齐柏林飞艇。然而,与织物有关的可充气产品包括的范围是很广的,并不仅仅限于“比空气轻”的飞行器具。．     

裤G不酷

商场门口正在举办一场"比酷"比赛。一座临时搭建的简易舞台后面,竖立着一个大大的广告牌,上面龙飞凤舞地写着"比比谁最酷"五个大字,舞台两侧分别摆着两只黑色的大音箱,里面响亮地播放着有     

竞技场上的奖励

在强烈的争强好胜心理驱使下,希腊人热衷于体育竞技,并用那种在其他地区只有神明才能享有的盛大仪式为胜利者欢庆。一个人如果在伯罗奔尼撒半岛上的艾里斯附近举行的奥林匹克竞技会上获得胜利,他将由一群观众簇拥着来到附近的宙斯庙。在神殿里,他将站在宙斯的神像前接受一顶由橄榄叶编成的花冠作为奖励品,并把它戴在头上。这些获得冠军的人可以享受到无穷无尽的荣耀:诗人们用诗歌来赞美他们,雕刻家为他们立像,悲剧作家幼里披底斯却对给予胜利者的这种如