다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

基礎講座 電気泳動(Electrophoresis)

/pdf/micro-total-analysis-systems-1-introduction-theory-and-27f7corp18.pdf

Micro Total Analysis Systems. 1. Introduction, Theory, and Technology

We survey progress over the past 25 years in the development of microscale devices for pumping fluids. We attempt to provide both a reference for micropump researchers and a resource for those outside the field who wish to identify the best micropump for a particular application. Reciprocating displacement micropumps have been the subject of extensive research in both academia and the private sector and have been produced with a wide range of actuators, valve configurations and materials. Aperiodic displacement micropumps based on mechanisms such as localized phase change have been shown to be suitable for specialized applications. Electroosmotic micropumps exhibit favorable scaling and are promising for a variety of applications requiring high flow rates and pressures. Dynamic micropumps based on electrohydrodynamic and magnetohydrodynamic effects have also been developed. Much progress has been made, but with micropumps suitable for important applications still not available, this remains a fertile area for future research.

https://microfluidics.stanford.edu/Publications/Micropumps_Cooling/Laser%20Review%20of%20Micropumps%20in%20JMM.pdf

A review of micropumps

Due to the smoothness of the surfaces in surface micromachining, large adhesion forces between fabricated structures and the substrate are encountered. Four major adhesion mechanisms have been analysed: capillary forces, hydrogen bridging, electrostatic forces and van der Waals forces. Once contact is made adhesion forces can be stronger than the restoring elastic forces and even short, thick beams will continue to stick to the substrate. Contact, resulting from drying liquid after release etching, has been successfully reduced. In order to make a fail-safe device stiction during its operational life-time should be anticipated. Electrostatic forces and acceleration forces caused by shocks encountered by the device can be large enough to bring structures into contact with the substrate. In order to avoid in-use stiction adhesion forces should therefore be minimized. This is possible by coating the device with weakly adhesive materials, by using bumps and side-wall spacers and by increasing the surface roughness at the interface. Capillary condensation should also be taken into account as this can lead to large increases in the contact area of roughened surfaces.

/pdf/stiction-in-surface-micromachining-s5wfxdssmg.pdf

Stiction in surface micromachining

The capillary filling speed of water in nanochannels with a rectangular cross section and a height on the order of 100 nm has been measured over a length of 1 cm. The measured position of the meniscus as a function of time qualitatively follows the Washburn model. Quantitatively, however, there is a lower than expected filling speed, which we attribute to the electro-viscous effect. For demineralized water in equilibrium with air the elevation of the apparent viscosity amounts up to 24±11% in the smallest channels (53 nm height). When using a 0.1 M NaCl (aq) solution the elevation of the apparent viscosity is significantly reduced.

Capillary filling speed of water in nanochannels

A simple to realise micro-liquid flow sensor with high sensitivity is presented. The sensor is based on well known thermal anemometer principles. An analytical model for the sensor behaviour applicable for gas/liquid fluids is presented. The realisation process of the sensor is described. Model and experimental results agree well. The sensor is simple to integrate with other micro-liquid handling components such as pumps, mixers, etc.

/pdf/micro-liquid-flow-sensor-427rlqac8n.pdf

Micro-liquid flow sensor

We have found evidence that water plugs in hydrophilic nanochannels can be at significant negative pressure due to tensile capillary forces. The negative pressure of water plugs in nanochannels induces bending of the thin channel capping layer, which results in a visible curvature of the liquid meniscus. From a detailed analysis of the meniscus curvature, the amount of bending of the channel capping can be calculated and used to determine the negative pressure of the liquid. For water plugs in silicon oxide nanochannels of 108 nm height, a negative pressure of 17 ± 10 bar was found. The absence of cavitation at such large negative pressures is explained by the fact that the critical radius for seeding cavities (bubbles) is comparable to the channel height. Scaling analysis of capillarity induced negative pressure shows that absence of cavitation is expected at other channel heights as well.

/pdf/capillarity-induced-negative-pressure-of-water-plugs-in-3zxga298pb.pdf

Capillarity Induced Negative Pressure of Water Plugs in Nanochannels

A theory is presented which describes the initial direct wafer bonding process. The effect of surface microroughness on the bondability is studied on the basis of the theory of contact and adhesion of elastic solids. An effective bonding energy, the maximum of which is the specific surface energy of adhesion, is proposed to describe the real binding energy of the bonding interface, including the influence of the wafer surface microroughness. Both the effective bonding energy and the real area of contact between rough surfaces depend on a dimensionless surface adhesion parameter, theta. Using the adhesion parameter as a measure, three kinds of wafer contact interfaces can be identified with respect to their bondability; viz. the nonbonding regime (theta > 12), the bonding regime (theta < 1), and the adherence regime (1 < theta < 12). Experimental data are in reasonable agreement with this theory

Niels Roelof Tas

Papers

Stiction in surface micromachining

Capillary filling speed of water in nanochannels

Micro-liquid flow sensor

Capillarity Induced Negative Pressure of Water Plugs in Nanochannels

The effect of surface roughness on direct wafer bonding