An improved method of sample injection was demonstrated for introducing ultra-low volume liquid on a microfabricated device. In our previous study, a pressure-driven injection method has been introduced and was applied to on-chip electrophoresis. In this study, the need for control of the air vent, which was indispensable for sample injection in the previous study, was completely eliminated, fa...

Because data are collected for only fatal crashes, it is difŽ cult to accurately measure seat belt and air bag effectiveness. The use of safety devices in uences survival rates which in turn determine whether a crash is included in the sample, leading to sample selection bias. We propose a simple solution to the selection problem: limiting the sample to crashes in which someone in a different ...

Mercury intrusion porosimetry (MIP) measurements are widely used to determine pore throat size distribution (PSD) curves of porous materials. The pore throat size of porous materials has been used to estimate their compressive strength and air permeability. However, the effect of sample size on the determined PSD curves is often overlooked. In pursuit of a better understanding of the effect of ...

STUDY OBJECTIVES To systematically review the evidence of randomized trials evaluating the effects of residential air filtration systems on patients with asthma. DATA SOURCES We searched for published and unpublished studies using MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Collaboration. We reviewed all reference lists for additional articles of re...

pan Association for Working Environment Measurement. The vapor pressures of these substances have been determined to be 2.5 •~ 10 mmHg for o-phthalodinitrile at 26•Ž, and 5 •~ 10-3 mmHg for acrylamide at 25•Ž, using the vapor saturation method.3) Due to sublimation on the filter, however, filter sampling of these substances may yield a lower value than their actual environmental concentration. ...

In dynamic plowing lithography, the sample surface is indented using a vibrating tip in tapping mode atomic force microscopy. During writing, the gap between the cantilever and the sample surface is very small, usually on the order of micrometers. High vibration frequency and small distance induce squeeze film air damping from the air in the gap. This damping can cause variations in the cantile...

A one hour integrated flask sampling system to collect air in automated NOAA/ESRL 12-flask packages is described. The integrating compressor system uses a mass flow controller to regulate the flow of air through a 15 l volume, thus providing a mixture of air collected over an hourlong period. By beginning with a high flow rate of 3.8 standard liters per minute and gradually decreasing the flow ...