Size Distributions of Organonitrates in Ambient Aerosol Collected in Houston,Texas

The size distributions of organonitrate functional groups in ambient Houston, TX aerosol were determined at 3 sites during an air quality field study conducted during August and September 2000. Samples were collected using a Hering low-pressure impactor and were analyzed, in transmission mode, using Fourier transform infrared spectroscopy. The size distributions of organonitrate groups generally fell into 4 categories. In approximately 25% of the samples, the majority of the organonitrate group mass was found in aerosol of approximately 0.1 w m aerodynamic diameter. In approximately 26% and 12% of the samples, the majority of the mass was found in aerosol of approximately 0.25 and 1 w m diameter, respectively; 21% of the samples displayed both 0.1 and 1 w m size modes. The remainder of the samples had relatively low organonitrate mass or other size distributions. Total organonitrate group absorbances, per m 3 of air sampled, were generally similar to measurements from samples collected in Los Angeles in previous studies, however,some samples had organonitrate absorbances that were an order of magnitude more intense than observed at urban sites in Los Angeles. The events with high organonitrate concentrations were observed at source-dominated (industrial) sites and were not correlated with either high NO x or high ozone concentrations, suggesting that the high concentrations are due to primary sources. The high organonitrate concentrations were generally accompanied by evidence of high acidity and high organic concentrations.     

Fabric filter bag investigation following field testing of sorbent injection for mercury control at TXU's Big Brown Station

Field testing of mercury control sorbent injection options with a TOXECON™ configuration has been completed at TXU's Big Brown Station. Mercury control results at Big Brown were promising and have been previously reported. However, the high air-to-cloth ratio of operations at this unit results in significant differential pressure, and thus there was little operating margin before differential pressure limits were encountered, especially at high loads. This limited the use of sorbent injection as the added material contributes to the overall differential pressure. After field testing, the residual differential pressure across the test fabric filter module had increased relative to baseline conditions to the point that the plant performed a filter change of the test module several months ahead of schedule. An investigation was conducted on pre- and posttest filter samples from the test module and a parallel nontest module to examine the effect of activated carbon injection. Analysis of the samples indicates an increase in residual dust embedded in the filters which appears to explain the low fabric permeabilities. The long-term increase in differential pressure did not appear to be associated with activated carbon injection, but instead was due to a gradual buildup of embedded material on the filters that was not cleaned away by the pulse cleaning system. The injected activated carbon appeared to behave like additional fly ash in terms of baghouse differential pressure but did not appear to accelerate the buildup of residual material.     

Preparation and characterisation of silica‐based nanoparticles for cisplatin release on cancer brain cells

In the present work, the preparation, characterisation, and efficiency of two different silica nanostructures as release vehicles of Cisplatin are reported. The 1‐hexadeciltrimethyl‐ammonium bromide templating agent was used to obtain mesoporous silica nanoparticles which were later loaded with Cisplatin. While sol–gel silica was very fast prepared using an excess of acetic acid during the hydrolysis–condensation reactions of tetraethylorthosilicate and at the same time the Cisplatin was added. Several physicochemical techniques including spectroscopies, electronic microscopy, X‐ray diffraction, N₂ adsorption–desorption were used to characterise the silica nanostructures. An in vitro Cisplatin release test was carried out using artificial cerebrospinal fluid. Finally, the toxicity of all silica nanostructures was tested using the C6 cancer cell line. The spectroscopic results showed the suitable stabilisation of Cisplatin into the two different silica nanostructures. A large surface area was obtained for the mesoporous silica nanoparticles, while low areas were obtained in the silica nanoparticles. Cisplatin was released faster from mesoporous silica channels than from inside of aggregates nanoparticles silica. Cisplatin alone, as well as, cisplatin released from both silica nanostructures exerted a toxic effect on cancer cells. In contrast, both silica structures without the drug did not exert any toxic effect.Inspec keywords: cellular biophysics, desorption, adsorption, biomedical materials, sol‐gel processing, silicon compounds, cancer, toxicology, nanofabrication, brain, condensation, mesoporous materials, nanoparticles, X‐ray diffraction, nanomedicine, drugs, aggregates (materials)Other keywords: mesoporous silica channels, silica‐based nanoparticles, cancer brain cells, silica nanostructures, 1‐hexadeciltrimethyl‐ammonium bromide, mesoporous silica nanoparticles, sol‐gel silica, C6 cancer cell line, in vitro cisplatin release test, C6 cancer cell line, acetic acid, hydrolysis‐condensation reactions, tetraethylorthosilicate, physicochemical techniques, electronic microscopy, X‐ray diffraction, N₂ adsorption‐desorption, artificial cerebrospinal fluid, toxicity, toxic effect, N₂ , SiO₂      

Genetic Associations of Alcohol Dehydrogenase With Alcohol Use Disorders and Endophenotypes in White College Students.

Associations of alcohol dehydrogenase (ADH) gene polymorphisms (ADH1B*2 and ADH1C*1) with a lifetime alcohol use disorder (AUD) were examined in White college students. Alcohol-related endophenotypes likely to be influenced by elevations in acetaldehyde were also assessed. Individuals with an ADH1B*2 allele had lower rates of AUDs, consumed a lower maximum number of drinks in a 24-hr period, reported a greater level of response to alcohol, were more likely to have experienced alcohol-induced headaches following 1 or 2 drinks, and reported more severe hangovers than those lacking this allele. These findings are consistent with the hypothesis that enhanced sensitivity to alcohol and lower levels of alcohol use reflect the mechanism by which ADH1B*2 protects against developing an AUD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of knowledge-based expectations in music perception: Evidence from musical restoration.

The perceptual restoration of musical sounds was investigated in 5 experiments with A. G. Samuel's (1981) discrimination methodology. Restoration in familiar melodies was compared to phonemic restoration in Experiment 1. In the remaining experiments, we examined the effect of expectations (generated by familiarity, predictability, and musical schemata) on musical restoration. We investigated restoration in melodies by comparing familiar and unfamiliar melodies (Experiment 2), as well as unfamiliar melodies varying in tonal and rhythmic predictability (Experiment 3). Expectations based on both familiarity and predictability were found to reduce restoration at the melodic level. Restoration at the submelodic level was investigated with scales and chords in Experiments 4 and 5. At this level, key-based expectations were found to increase restoration. Implications for music perception, as well as similarities between restoration in music and speech, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrating biological and behavioral factors in alcohol use risk: The role of ALDH2 status and alcohol expectancies in a sample of Asian Americans.

Prior studies have shown that the ALDH2*2 genetic variant, most common in individuals of Asian descent, is related to heightened sensitivity to alcohol and can serve as a protective factor against alcohol problems. This study explored the effect of this factor on alcohol expectancies. It was hypothesized that (a) individuals with ALDH2*2 alleles would have lower positive expectancies and higher negative expectancies, (b) expectancies would mediate the ALDH2-drinking relation, and (c) ALDH2 status would moderate the expectancy-drinking relation. Data were collected from 171 Asian American university students. Positive expectancy and ALDH2 status were correlated with alcohol use. Mediation and moderation hypotheses were supported only in the female sample. Results were not significant for negative expectancies. These results indicate that ALDH2 status may protect against drinking by lowering positive expectancies and reducing the expectancy-drinking relationship. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flexible automated approach for quantitative liquid handling of complex biological samples

A fully automated protein precipitation technique for biological sample preparation has been developed for the quantitation of drugs in various biological matrixes. All liquid handling during sample preparation was automated using a Hamilton MicroLab Star Robotic workstation, which included the preparation of standards and controls from a Watson laboratory information management system generated work list, shaking of 96-well plates, and vacuum application. Processing time is less than 30 s per sample or approximately 45 min per 96-well plate, which is then immediately ready for injection onto an LC-MS/MS system. An overview of the process workflow is discussed, including the software development. Validation data are also provided, including specific liquid class data as well as comparative data of automated vs manual preparation using both quality controls and actual sample data. The efficiencies gained from this automated approach are described.     

Risk-based classification and interactive map of watersheds contributing anthropogenic stress to Laurentian Great Lakes coastal ecosystems

We describe development anthropogenic stress indices for coastal margins of the Laurentian Great Lakes basin. Indices were derived based on the response of species assemblages to watershed-scale stress from agriculture and urbanization. Metrics were calculated for five groups of wetland biota: diatoms, wetland vegetation, aquatic invertebrates, fishes, and birds. Previously published community change points of these assemblages were used to classify each watershed as ‘least-disturbed’, ‘at-risk’, or ‘degraded’ based on community response to these stressors. The end products of this work are an on-line map utility and downloadable data that characterize the degree of agricultural land use and development in all watersheds of the US and Canadian Great Lakes basin. Discrepancies between the observed biological condition and putative anthropogenic stress can be used to determine if a site is more degraded than predicted based on watershed characteristics, or if remediation efforts are having beneficial impacts on site condition. This study provides a landscape-scale evaluation of wetland condition that is a critical first step for multi-scale assessments to help prioritize conservation or restoration efforts.     

Sorbent injection into a slipstream baghouse for mercury control: Project summary

A project led by the Energy and Environmental Research Center to test and demonstrate sorbent injection as a cost-effective mercury control technology for utilities burning lignites has shown effective mercury capture under a range of operating conditions. Screening, parametric, and long-term tests were carried out at a slipstream facility representing an electrostatic precipitator–activated carbon injection–fabric filter configuration (called a TOXECON™ in the United States). Screening tests of sorbent injection evaluated nine different sorbents, including both treated and standard activated carbon, to compare mercury capture as a function of sorbent injection rate. Parametric tests evaluated several variables including air-to-cloth (A/C) ratio, flue gas temperature, cleaning frequency, and dust loading to determine the effect on mercury control and systems operation. Long-term tests (approximately 2 months in duration) evaluated the sustainability of systems operation.     

Mercury control technologies for coal combustion and gasification systems

Development and testing of mercury control technologies have largely focused on coal-fired combustion systems, with less emphasis on advanced power systems. Mercury control is influenced by coal properties and chemistry, plant configuration, pollution control devices, flue gas conditions, and plant operations, which differ between combustion and gasification systems. Sorbents such as treated activated carbons have shown promising results in low-temperature environments; however, elevated temperature and reducing environments of many advanced systems remain challenging, requiring research and development to obtain acceptable mercury control levels. Concurrent pollutant/multipollutant control strategies that include CO₂ control are critically needed for both conventional and advanced power systems.