PubMed · 7191594
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R K Mueller. 1980. Diffraction tomography I: The wave-equation.. https://doi.org/10.1177/016173468000200302
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The influences of temperature and atmospheric humidity on the performance of an array of eight polymer-coated 158-MHz surface acoustic wave vapor sensors were investigated. Sensitivities to the seven organic vapors examined all exhibited negative Arrhenius temperature dependencies, with responses increasing by factors of 1.5-4.4 on going from 38 to 18 degrees C. The magnitudes of the temperature effects, while generally similar, differed sufficiently among certain sensor-vapor combinations to cause marked changes in vapor response patterns. In addition, it was found that operating identically coated sensors at different temperatures could provide a means for discriminating certain vapors. The changes in sensor responses with temperature agreed reasonably well with those expected assuming ideal vapor sorption behavior and indicated that changes in the moduli of the sensor coatings were not important mediating factors. Responses to relative humidity (RH) from 0 to 85% RH were important even for the nonpolar sensor coatings. Significant changes in the sensitivities to the organic vapors were observed as a function of atmospheric humidity for several sensor-vapor combinations, which, in turn, affected the patterns of responses obtained from the sensor array. Results indicate that small changes in temperature or humidity have a larger effect on baseline stabilities than on the responses to the vapors. Monte Carlo simulations of sensor responses show that the ability to discriminate vapors in binary and ternary mixtures using a four-sensor array remains high regardless of the operating temperature and ambient humidity, provided that temperature-or humidity-induced changes in the response patterns are taken into account.
Objective measures of upper respiratory function are needed to understand the effects of inhaled toxicants on the nasal passages. Acoustic rhinometry (AR) is a simple new technique that determines nasal volume by measuring the cross-sectional area of the upper airway as a function of the distance along the nasal passage. This study compares acoustic rhinometry with the more traditional posterior rhinomanometry (NAR) and correlates these objective measures with the symptom of nasal congestion. Healthy young adults (n = 29) were studied on 4 days, each separated by at least 1 wk, in a climate-controlled environmental chamber for 6 h, with exposure to clean air or sidestream tobacco smoke (SS) (2 h, 1, 5, and 15 ppm CO). The coefficient of variation for single measurements was 8-15% (AR) and 4% (NAR); for across-day measurements it was 15-25% (AR) and 13-15% (NAR); and for between days it was 19-27% AR and 17-21% (NAR). These coefficients were similar in subjects with a history of environmental tobacco smoke sensitivity (ETS-S) and those with no history of ETS sensitivity (ETS-NS). At baseline, the perception of unilateral nasal congestion was significantly correlated with unilateral nasal dimensions or nasal resistance; the symptom of baseline bilateral nasal congestion (estimated for both nasal passages simultaneously) correlated less well with objective measures of nasal patency. Under challenge conditions (SS at 1-15 ppm CO), there were typically significant correlations between changes in unilateral congestion and both unilateral rhinomanometry and acoustic rhinometry, but correlations of bilateral congestion and measurable dimensions were much lower. ETS-S and ETS-NS subjects differed in correlations between bilateral subjective and objective measures: ETS-S subjects showed significant correlation between baseline congestion and NAR; in contrast, ETS-NS subjects showed significant correlation between baseline congestion and acoustic rhinometry. These results indicate that NAR and AR are complementary tests for use in inhalation challenge studies and have different correlations with nasal congestion under baseline and challenge conditions.
A technique was developed for the ultramicro-analysis of proteins electrophoresed by Laemmli's method using a light-scanning photoacoustic densitometer. After electrophoresis, the proteins were blotted on a nitrocellulose membrane filter and colored by the avidin-biotin complex method. This filter was then measured using a photoacoustic densitometer. The optimal blotting time was 150 min. The relative standard deviation of four measurements was 3.89% for 200 ng bovine serum albumin (BSA). The limits of detection were 2.3, 0.69, 4.4, and 2.9 ng (S/N = 3) for BSA, ovalbumin, carbonic anhydrase, and alpha-Lactoalbum respectively. Proteins eluted from hair by various harmful agents, such as a surfactant and UV irradiation, were analyzed by the present method. Using 2-mercaptoethanol, the molecular weights of proteins in hair were in the range of 14,000-64,000. Maximal elution of protein was obtained at pH 8. More protein was eluted under alkaline conditions than under acidic conditions. A protein of Mr 68,000 was eluted from hair by oxidative treatment with either UV irradiation or sodium bromate.