Continuous measurement of reactive oxygen species inside and outside of a residential house during summer

Reactive oxygen species (ROS) are an important contributor to adverse health effects associated with ambient air pollution. Despite infiltration of ROS from outdoors, and possible indoor sources (eg, combustion), there are limited data available on indoor ROS. In this study, part of the second phase of Air Composition and Reactivity from Outdoor aNd Indoor Mixing campaign (ACRONIM-2), we constructed and deployed an online, continuous, system to measure extracellular gas- and particle-phase ROS during summer in an unoccupied residence in St. Louis, MO, USA. Over a period of one week, we observed that the non-denuded outdoor ROS (representing particle-phase ROS and some gas-phase ROS) concentration ranged from 1 to 4 nmol/m³ (as H₂O₂). Outdoor concentrations were highest in the afternoon, coincident with peak photochemistry periods. The indoor concentrations of particle-phase ROS were nearly equal to outdoor concentrations, regardless of window-opening status or air exchange rates. The indoor/outdoor ratio of non-denuded ROS (I/O_ROS) was significantly less than 1 with windows open and even lower with windows closed. Combined, these observations suggest that gas-phase ROS are efficiently removed by interior building surfaces and that there may be an indoor source of particle-phase ROS.     

Interpretation of Volatility Tandem Differential Mobility Analyzer (V-TDMA) data for accurate vapor pressure and enthalpy measurement: Operational considerations,multiple charging,and introduction to a new analysis program (TAO)

Abstract

Significant evaporation of pure aerosols in a Volatility Tandem Differential Mobility Analyzer (V-TDMA) creates two Condensation Particle Counter (CPC) response peaks. Two hypotheses for the observed peaks have been proposed: the existence of two phases or the separation of the singly charged experimental size distribution from the remaining experimental size distributions with charges greater than 1 (charge separation). To explore this observation, we atomized pure levoglucosan aerosol and evaporated the aerosol until two peaks formed. We used an additional classifier and neutralizer to select particles from each of the two peaks and assessed the number of charges on the particles. The smaller diameter peak contained singly charged particles, and the larger diameter peak contained the remaining charges. The charge separation hypothesis alone accounts for the two-peak observations. We used a new V-TDMA model named TAO and show that charge separation should occur in other pure components as well. The TAO model was then used to display the impact of different DMA transfer functions, different inlet size distributions, and different oven residence time distributions (RTDs) on the CPC response. Large errors are possible when direct measurement of the RTD is not performed or when wide RTDs are used. We recommend use of narrow transfer functions with narrow RTDs to detect charge separation. When the singly charged CPC response is isolated (smaller diameter peak in the two peak response), accurate estimations of vapor pressure can be recovered, assuming accurate values for gas phase diffusivity, surface energy, particle density, etc. are used.

Copyright © 2020 American Association for Aerosol Research     

Work experiences and personality development in young adulthood.

This longitudinal study provides an analysis of the relationship between personality traits and work experiences with a special focus on the relationship between changes in personality and work experiences in young adulthood. Longitudinal analyses uncovered 3 findings. First, measures of personality taken at age 18 predicted both objective and subjective work experiences at age 26. Second, work experiences were related to changes in personality traits from age 18 to 26. Third, the predictive and change relations between personality traits and work experiences were corresponsive: Traits that "selected" people into specific work experiences were the same traits that changed in response to those same work experiences. The relevance of the findings to theories of personality development is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intensive forest clearing in Rondonia,Brazil, as detected by satellite remote sensing

Imagery from the National Oceanic and Atmospheric Administration satellite's Advanced Very High Resolution Radiometer sensor has been used to identify an area about 100 × 400 km in Rondonia (Brazil) where massive forest clearing or deforestation is occurring. A field study verified the area of the clearing, which is associated with a large colonization program.     

Activation of stimulus-secretion coupling in pancreatic beta-cells by specific products of glucose metabolism. Evidence for privileged signaling by glycolysis

The energy requirements of most cells supplied with glucose are fulfilled by glycolytic and oxidative metabolism, yielding ATP. In pancreatic beta-cells, a rise in cytosolic ATP is also a critical signaling event, coupling closure of ATP-sensitive K+ channels (KATP) to insulin secretion via depolarization-driven increases in intracellular Ca2+ ([Ca2+]i). We report that glycolytic but not Krebs cycle metabolism of glucose is critically involved in this signaling process. While inhibitors of glycolysis suppressed glucose-stimulated insulin secretion, blockers of pyruvate transport or Krebs cycle enzymes were without effect. While pyruvate was metabolized in islets to the same extent as glucose, it produced no stimulation of insulin secretion and did not block KATP. A membrane-permeant analog, methyl pyruvate, however, produced a block of KATP, a sustained rise in [Ca2+]i, and an increase in insulin secretion 6-fold the magnitude of that induced by glucose. These results indicate that ATP derived from mitochondrial pyruvate metabolism does not substantially contribute to the regulation of KATP responses to a glucose challenge, supporting the notion of subcompartmentation of ATP within the beta-cell. Supranormal stimulation of the Krebs cycle by methyl pyruvate can, however, overwhelm intracellular partitioning of ATP and thereby drive insulin secretion.     

Social skills of and social environments produced by different Holland types: A social perspective on person€nvironment fit models.

Acritical aspect of the environment in person–environment models is the nature and density of the social interactions of the members who populate the environment. Because social types solve problems through social mechanisms, it was hypothesized that they would have greatest skills in social coping and that the further the Euclidean distance (in Holland's hexagon) from social, the lower the skill level would be in these social skills. It was also hypothesized that there would be no differences among Holland types in skill level for problem-focused social skills. On the basis of an assessment of vocational interests and self-reported social skills of 134 undergraduates, these hypotheses were corroborated. Chemistry laboratory groups were qualitatively studied to describe the social interaction environment of persons with relative deficits in the social-coping skills. These chemists interacted often, enjoyed and benefited from the interactions, but constrained their social interactions to minimize the dependence on social-coping social skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement and representation of grain-boundary texture

The measurement and representation of grain-boundary texture in single-phase polycrystals are examined in this article. Grain-boundary texture is assumed to be fully defined by the lattice orientation of two grains which come together to form the boundary and by the orientation of the boundary relative to the two lattices. Representations which incorporate more limited def- initions of local grain-boundary structure are easily considered in natural subspaces of the more complete representation. The two major stereologies which have been developed for measuring grain-boundary texture from random sectioning are compared in detail. It is demonstrated that the stereological method of Hilliard, [3] which obtains the distribution of boundary normals from intersections of the boundaries with random test lines placed on random sections, cannot dis- tinguish “sided” grain-boundary textures. The stereological method of Adams, [5] which obtains the boundary normal distribution from the angular distribution of boundary intersections in ran- dom sections, is shown to be more general, since it is not limited to “nonsided” grain-boundary textures. It is also shown that the latter stereology obtains a more accurate representation of the boundary-normal distribution, as compared with the former, for an equivalent number of section planes. Formerly Graduate Student, Yale University.     

Chemical and structural effects on the electronic states of (Hg, Tl, Pb, Bi)-based cuprate superconductors

The electronic energy bands have been calculated for the new single-layer and triple-layer Hg-based superconductors, HgBa₂CuO₄ and HgBa₂Ca₂Cu₃O_y, for the analogous Tl-and Bi-based materials, and for hypothetical Pb-based materials. As one moves across the last row of the periodic table, from Hg to Bi,s- andp-derived bands pass below the Fermi energy, to influence hole doping of the copper oxide planes and transport in the other layers of the material. The dispersion of these bands is significantly affected by the crystal structure. The calculations were performed with a simple chemical model.     

Effect of disabled counselors' self-disclosures on client perceptions of the counselor.

In a videotaped counseling analog, 2 male counselors each portrayed (a) an obviously disabled counselor in a wheelchair and (b) a not obviously disabled counselor with visual impairment. Within each condition, counselors did or did not make self-disclosures about their disability. Ss were 169 university students, none of whom was disabled or had close friends or relatives who were disabled. Results indicate that counselors in several of the disability conditions were rated as being significantly more expert and attractive than able-bodied counselors. Counselor self-disclosures did not have a clearly negative or positive effect on Ss' perceptions. The hypothesis that awareness of a counselor's disability may enhance client perceptions of his or her credibility is discussed. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)