The influence of contact pressure, moisture, and compression time on the performance of cotton anti-contamination clothing

The objectives of this research were (1) to study the effect of contact pressure, compression time, and liquid (moisture content of the fabric) on the transfer by sliding contact of non-fixed surface contamination to protective clothing constructed from uncoated, woven fabrics, (2) to study the effect of contact pressure, compression time, and liquid content on the subsequent penetration through the fabric, and (3) to determine if varying the type of contaminant changes the effect of contact pressure, compression time, and liquid content on the transfer by sliding contact and penetration of non-fixed surface contamination. ^ It was found that the combined influence of the liquid (moisture content of the fabric), load (contact pressure), compression time, and their interactions significantly influenced the penetration of all three test agents, sucrose- 14C, triolein-3H, and starch-14C through 100% cotton fabric. The combined influence of the statistically significant main effects and their interactions increased the penetration of triolein- 3H by 32,548%, sucrose-14C by 7,006%, and starch- 14C by 1,900%. ^

Characterization of the East Houston particulate matter <2.5 atmosphere; a novel method for desorbing organic constituents from airborne particulates

I have developed a novel approach to test for toxic organic substances adsorbed onto ultra fine particulate particles present in the ambient air in Northeast Houston, Texas. These particles are predominantly carbon soot with an aerodynamic diameter (AD) of <2.5 μm. If present in the ambient air, many of the organic substances will be absorbed to the surface of the particles (which act just like a charcoal air filter), and may be adducted into the respiratory system. Once imbedded into the lungs these particles may release the adsorbed toxic organic substances with serious health consequences. I used a Airmetrics portable Minivol air sampler time drawing the ambient air through collection filters samples from 6 separate sites in Northeast Houston, an area known for high ambient PM 2.5 released from chemical plants and other sources (e.g. vehicle emissions).(1) In practice, the mass of the collected particles were much less than the mass of the filters. My technique was designed to release the adsorbed organic substances on the fine carbon particles by heating the filter samples that included the PM 2.5 particles prior to identification by gas chromatography/mass spectrometry (GCMS). The results showed negligible amounts of target chemicals from the collection filters. However, the filters alone released organic substances and GCMS could not distinguish between the organic substances released from the soot particles from those released from the heated filter fabric. However, an efficacy tests of my method using two wax burning candles that released soot revealed high levels of benzene. This suggests that my method has the potential to reveal the organic substances adsorbed onto the PM 2.5 for analysis. In order to achieve this goal, I must refine the particle collection process which would be independent of the filters; the filters upon heating also release organic substances obscuring the contribution from the soot particles. To obtain pure soot particles I will have to filter more air so that the soot particles can be shaken off the filters and then analyzed by my new technique. ^

DEVELOPMENT AND APPLICATION OF SHORT-TERM MUTAGENICITY AND CYTOTOXICITY BIOASSAYS FOR INTEGRATED HEALTH ASSESSMENT STUDIES OF COAL FLY ASH EMISSIONS

Two respirable coal fly ash samples ((LESSTHEQ) 3(mu)m), one from a pressurized fluidized-bed combustion miniplant and one from a conventional combustion power plant, were investigated for physical properties, chemical composition and biological activity. Electron microscopy illustrated irregularity in fluidized-bed combustion fly ash and sphericity in conventional combustion fly ash. Elemental analysis of these samples showed differences in trace elements. Both fly ash samples were toxic in rabbit alveolar macrophage and Chinese hamster ovary cell systems in vitro. The macrophages were more sensitive to toxicity of fly ash than the ovary cells. For measuring the cytotoxicity of fly ash, the most sensitive parameters were adenosine triphosphate in the alveolar macrophage system and viability index in the hamster ovary system. Intact fluidized-bed combustion fly-ash particles showed mutagenicity only in strains TA98 and TA1538 without metabolic activation in the Ames Salmonella assay. No mutagenicity was detected in bioassay of conventional combustion fly ash particles. Solvent extraction yielded more mass from fluidized-bed combustion fly ash than from conventional combustion fly ash. The extracts of fluidized-bed combustion fly ash showed higher mutagenic activity than conventional combustion fly ash. These samples contained direct-acting, frameshift mutagens.^ Fly ash samples collected from the same fluidized-bed source by cyclones, a fabric filter, and a electrostatic precipitator at various temperatures were compared for particle size, toxicity, and mutagenicity. Results demonstrated that the biological activity of coal fly ash were affected by the collection site, device, and temperature.^ Coal fly ash vapor-coated with 1-nitropyrene was developed as a model system to study the bioavailability and recovery of nitroaromatic compounds in fly ash. The effects of vapor deposition on toxicity and mutagenicity of fly ash were examined. The nitropyrene coating did not significantly alter the ash's cytotoxicity. Nitropyrene was bioavailable in the biological media, and a significant percentage was not recovered after the coated fly ash was cultured with alveolar macrophages. 1-Nitropyrene loss increased as the number of macrophages was increased, suggesting that the macrophages are capable of metabolizing or binding 1-nitropyrene present in coal fly ash. ^

Volunteering: Demographic characteristics, motives and potential benefits from service

Volunteering is intricately woven into the fabric of our society. In 2009 alone, approximately 63.4 million Americans participated in volunteer activities, collectively donating over 8.1 billion service-hours (Corporation for National and Community Service [CNCS], 2010). Each service-hour is determined by the U.S. Bureau of Labor Statistics (2010) to be valued at $20.85/hr which translates to a national savings of $169 billion. Thus, we can clearly observe the significance of volunteer contribution to the overall benefit of society. In addition, there is now evidence that voluntary service may also benefit the actual volunteer, especially individuals who are 65+ years. As we reach 2020 this elderly class, composed of nearly 13 million (CNCS, 2010) Americans, will be of much consequence. Their potential to contribute in community-related efforts may save the U.S. billions in labor costs, and may also help reduce healthcare-related expenditures if volunteering proves to be a protective factor. In this literature review, we set out to explore the potential relationship between volunteer participation and increased mental and physical wellness. We also examined volunteer demographic characteristics and common motives for engaging in service-related activities. Analysis showed that volunteer work often combined low-impact physical activity and mental satisfaction from serving others, resulting in overall health benefit. Demographic characteristics displayed were consistent with previous studies and found that a majority of volunteers were female, White, married status, having received college degree or higher, employed, middle-high SES. In addition, age was seen to be a key characteristic in forecasting volunteer motivation and self-reported perceived health benefits.^

Change in permeation rates of acids and bases through limited use protective fabrics after repeated wash cycles

The primary objective of this study was to determine if there is a change in permeation rates when limited use protective fabrics undergo repeated exposure and wash cycles. The null hypothesis of this study was that no substantial change in permeation takes place after the test material is subjected to repeated contact with a strong acid or base and has undergone repeated wash cycles. ^ The materials tested were DuPont Tychem® CPF 3 and CPF 4 fabrics. The challenge chemicals in this study were ninety-eight percent sulfuric acid and fifty percent sodium hydroxide. Permeation testing was conducted utilizing ASTM designation F739-99a Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases Under Conditions of Continuous Contact. ^ In this study, no change in permeation rates of either challenge chemical was detected for CPF 3 or CPF 4 limited use protective fabrics after repeated exposure and wash cycles. Certain unexposed areas of the fabric suffered structural degradation unrelated to exposure and which may be due to multiple washings.^