Recruitment and selection of couples for intervention research: Achieving developmental homogeneity at the cost of demographic diversity.

Demographic and relationship quality data were collected from 704 individuals recruited to participate in a randomized study of relationship enhancing interventions. Recruiting at bridal shows produced partners who were more satisfied, earlier in their relationships, and less likely to be parents, with a marginally higher proportion of Latino couples. Radio and television coverage produced more established couples with higher levels of relationship discord. Self-selection effects revealed that couples from demographic groups at greater risk for divorce (those who had not completed high school, those with children at marriage, and African American couples) were more likely to agree to participate. In contrast, imposing a set of common selection criteria served to exclude couples from demographic risk groups and selected for couples with higher marital quality. Implications for recruiting couples to participate in preventive interventions are outlined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photocatalytic degradation of organic pollutants with simultaneous production of hydrogen

The photocatalytic degradation of a number of organic compounds in solution, including alcohols and organic acids, has been investigated under unaerated conditions with the use of Pt/TiO₂ photocatalyst and solar or UV irradiation. It has been found that production of CO₂ is in all cases accompanied by evolution of hydrogen, the production rate of which is significantly enhanced, compared with that obtained in the absence of organic additives in solution. Results are explained by considering that organic compounds act as sacrificial electron donors, which become progressively oxidized toward CO₂ by consuming photogenerated holes and/or oxygen. This results in decreased rates of electron–hole recombination and oxygen–hydrogen back reaction and, concomitantly, in increased H₂-production rates. The rate of photoinduced hydrogen production depends strongly on the concentration of the sacrificial agent employed and to a lesser extent on solution pH and temperature. When complete mineralization of the sacrificial agent is achieved, photogenerated oxygen can no longer be removed from the photocatalyst surface and the H₂-production rate drops to steady-state values, comparable to those obtained in the absence of the organic compound in solution. The amounts of carbon dioxide and “additional” hydrogen produced depend on the nature of the organic additive and are directly proportional to its initial concentration in solution. Quantification of results shows that the overall process may be described as “photoinduced reforming of organic compounds at room temperature”. It is concluded that mineralization of organic pollutants such as alcohols and organic acids, which are common waste products of biomass processing industries, can be achieved with simultaneous production of H₂ fuel. The process may provide an efficient and cost effective method for cleaning up waste streams.     

Rapid Performance Evaluation and Optimal Sizing of Dry Cyclone Separators

Cyclones are generally less efficient than other kinds of equipment, but their simple construction, low energy requirements, and ability to operate at high temperatures and pressures make them attractive for cleaning up gases. Despite the simplicity in construction and operation, complex mathematical formulations are used for predicting the collection efficiency of particles of a given diameter. These must be numerically integrated, along with the inlet particle-size-distribution functions that are appropriate in each application, in order to obtain the overall cyclone efficiency. In this paper, the above cumbersome procedure is simplified through nomographs allowing rapid, yet rigorous, estimation of the overall cyclone efficiencies based on two alternative and well-established approaches and on the sole assumption of a lognormal particle-size distribution. Along with the above, pressure drop and limiting inlet velocity correlations are also considered, and each of the above nomographs is combined with others, providing direct graphical representation of the so far obscure relationships among cyclone diameter, overall efficiency, and gas pressure drop or flow rate. The paper thus affords an overview of cyclone behavior over a wide range of conditions, offering direct solutions to both cyclone performance and optimal cyclone design problems.     

Comparative Fractional Efficiency Predictions by Selected Cyclone Simulation Models

The recently introduced ambient air quality standards for fine particulates expand the use of available control system simulation models, from the prediction of total particulate matter removal efficiencies, to the prediction of PM2.5 and PM10 (particulate matter with diameters less than 2.5 and 10?μm) ones. In order to assess the suitability of cyclone simulation models for this task, the fractional efficiency predictions of six prominent models (Lapple, Leith and Licht, Dietz, Mothes and Loffler, Iozia and Leith, and Mothes and Loffler with the turbulent dispersion coefficient of Salcedo and Coelho) are compared for a number of “standard” cyclone design configurations under a wide range of cyclone diameters and pressure drops. The results reveal a significant discrepancy among model predictions, suggesting that at least some of the models considered are unsuitable for predicting size-specific (e.g., PM2.5 and PM10) cyclone efficiencies. They also show that the sensitivity of fractional efficiencies to changes in the configuration ratios, diameter, and gas pressure drop varies widely, and in some cases even in opposite directions, among models. The above-noted results demonstrate the need for a systematic model validation against credible and sufficiently extensive experimental data sets.     

Enhancement of photoinduced hydrogen production from irradiated Pt/TiO2 suspensions with simultaneous degradation of azo-dyes

The production of hydrogen from aqueous Pt/TiO₂ suspensions illuminated with UV–vis light has been examined in the absence and in presence of azo-dyes in solution. The effects of operational variables, including dye concentration, solution pH and temperature, on the rate of hydrogen production were investigated. It has been found that deposition of Pt (0.5 wt.%) on the semiconductor surface results in an increase of the H₂ production rate, which goes through a maximum with time of irradiation and then drops to steady-state values comparable to those obtained over bare TiO₂. Both, maximum and steady-state rates obtained over Pt/TiO₂ suspensions were found to increase with increasing solution pH and temperature. Addition of small quantities of azo-dyes in solution results in significantly enhanced rates of H₂ production for a period which depends on dye concentration, solution pH and, to a lesser extent, solution temperature. It is proposed that the dye acts as a scavenger of photogenerated oxidizing species while it is degraded toward CO₂ and inorganic ions. When complete mineralization is achieved, oxygen can no longer be removed from the photocatalyst surface and the rate drops to steady-state values, comparable to those obtained in the absence of azo-dye in solution. The amount of additional H₂ produced is directly proportional to the amount of dye added in the solution. The rate increases with increasing solution pH, where dye degradation is faster, indicating that the process is limited by the rate of consumption of photogenerated oxygen. It is concluded that, under certain experimental conditions, it is possible to obtain significantly enhanced rates of photoinduced hydrogen production from Pt/TiO₂ suspensions with simultaneous mineralization of azo-dyes. The process could be used for combined production of fuel H₂ and degradation of organic pollutants present in water.     

Aberrant Mitochondrial Dynamics and Exacerbated Response to Neuroinflammation in a Novel Mouse Model of CMT2A

Charcot-Marie-Tooth disease type 2A (CMT2A) is the most common hereditary axonal neuropathy caused by mutations in MFN2 encoding Mitofusin-2, a multifunctional protein located in the outer mitochondrial membrane. In order to study the effects of a novel MFN2^K357T mutation associated with early onset, autosomal dominant severe CMT2A, we generated a knock-in mouse model. While Mfn2^K357T/K357T mouse pups were postnatally lethal, Mfn2^+/K357T heterozygous mice were asymptomatic and had no histopathological changes in their sciatic nerves up to 10 months of age. However, immunofluorescence analysis of Mfn2^+/K357T mice revealed aberrant mitochondrial clustering in the sciatic nerves from 6 months of age, in optic nerves from 8 months, and in lumbar spinal cord white matter at 10 months, along with microglia activation. Ultrastructural analyses confirmed dysmorphic mitochondrial aggregates in sciatic and optic nerves. After exposure of 6-month-old mice to lipopolysaccharide, Mfn2^+/K357T mice displayed a higher immune response, a more severe motor impairment, and increased CNS inflammation, microglia activation, and macrophage infiltrates. Overall, ubiquitous Mfn2^K357T expression renders the CNS and peripheral nerves of Mfn2^+/K357T mice more susceptible to mitochondrial clustering, and augments their response to inflammation, modeling some cellular mechanisms that may be relevant for the development of neuropathy in patients with CMT2A.     

Semisynthetic Vitamin E Derivatives as Potent Antibacterial Agents against Resistant Gram-Positive Pathogens

New 5-substituted vitamin E derivatives were semisynthesized, and their antibacterial activity against human Gram-positive and Gram-negative pathogens was evaluated. Several vitamin E analogues were active against methicillin-resistant Staphylococcus aureus (MRSA) and/or methicillin-resistant Staphylococcus epidermidis (MRSE); structure-activity relationships (SARs) are discussed. As a result, it is shown that the presence of a carboxylic acid function at the C-5 position and/or at the end of the side chain is crucial for the antibacterial activity. The bactericidal or bacteriostatic action of three compounds against MRSA and MRSE was confirmed in a time-kill kinetics study, and the cytotoxicity on human cells was evaluated. The preliminary mechanism study by confocal microscopy indicated that those vitamin E analogues led to bacterial cell death through membrane disruption.