Winner of the 1999 best medical student paper in preventive medicine. Don't hold your breath: personal exposures to volatile organic compounds and other toxins in indoor air and what's (not) being done about it.

BACKGROUND: Since the inception of the environmental movement early in the 1970s, the majority of regulation, laws, and standards regarding pollutants have focused on the release of pollutants into our air and water rather than on the extent of exposure. As a consequence, the actual amounts of toxic pollutants to which humans are continually exposed have long been ignored. Moreover, regulation and assessment of pollution have focused primarily on ambient environmental levels. This fails to adequately examine the state of indoor air. This is of particular concern and deserving of more attention, considering that a majority of people spend the majority of their time at home, RESULTS: Studies on indoor air quality suggest that, within the home, people are exposed to high levels of numerous pollutants. Of particular concern are the levels of polycyclic aromatic hydrocarbons and volatile organic compounds because many of these are known carcinogens. While the need for further study is clear, what evidence there is already warrants the establishment of indoor air regulation and the implementation of preventive measures. For such measures to be effective, a great deal of education and outreach will be necessary. Also, health care providers must play an active role.

Studies on the Biotin-Avidin Multilayer Adsorption by Spectroscopic Ellipsometry.

Protein multilayers were prepared on silica surfaces by up to 20 alternating incubations of a biotin-protein conjugate and polymerized streptavidin. Spectroscopic ellipsometry (350-750 nm) was used to investigate the physical thickness and the dispersion of the protein layer after each incubation step. Both parameters could be determined independently for films formed by 5 to 15 incubations. A single homogeneous protein layer was assumed for evaluation. This determination of layer parameters was limited by high correlation coefficients for less than 5 incubation steps. Deviations from the homogeneous single layer model were found for more than 15 incubation steps. The growth of the layer was reproducible, with a thickness increase of about 18.75 nm per incubation. An almost constant refractive index nD of 1.384 +/- 0.002 was found for the multilayer system. A protein mass deposition of 4.74 ng/mm2 was calculated per incubation step. The protein concentration of the layer was estimated of about 0.27 g/ml. The affinity system investigated is quite simple and may well serve as a prototype system in the characterization of optical and other transducers for affinity reactions. Copyright 1997 Academic Press.