Enhanced susceptibility to infection in mice after exposure to dilute exhaust from light duty diesel engines

A series of experiments was conducted in which groups of mice were first exposed for various durations to diluted exhaust from light duty diesel engines and then briefly to an infectious aerosol generated by nebulizing cultures of a bacterial pathogen (Streptococcus). Typically, postinfection mortality was significantly greater in groups exposed to exhaust than in their corresponding control groups exposed to purified air only. Data of recent diesel and of past diesel- and catalyst-treated gasoline engine exhaust experiments suggest a somewhat greater excess mortality from (enhanced susceptibility to) bacterial infection in mice exposed to diesel exhaust than in those exposed to catalytic gasoline exhaust. Limited data on acute tests of NO₂ and acrolein vapor alone suggest that the infectivity-enhancing effect of diesel exhaust could be accounted for in large part by these components. Exposures to diesel exhaust, NO₂, or acrolein did not enhance the mortality response to a viral pathogen (A/PR8-34).     

Synthesis of an organic–inorganic composite from calcium carbonate and Kraft lignin and its use as carrier material for controlled release of semiochemical agents

Environmental Science and Pollution Research - The control of pests in agricultural systems is currently based on the widespread use of pesticides that efficiently control pests but have negative...     

Adsorption of molybdate and tetrathiomolybdate onto pyrite and goethite: effect of pH and competitive anions

The adsorption of two major molybdenum (Mo) species, molybdate (MoO4(2-)) and tetrathiomolybdate (MoS4(2-)) onto two main iron minerals pyrite (FeS2) and goethite (FeOOH) is addressed to elucidate the possible mechanisms of molybdenum immobilization in anoxic sediments. Suspensions of MoS4(2-) (or MoO4(2-)) and goethite (or pyrite) in 0.1M NaCl solution were equilibrated under anoxic conditions at 25 degrees C in the pH range from 3 to 10. The competitive effects of sulfate, phosphate, and silicate on the adsorption of MoO4(2-) and MoS4(2-) by pyrite and goethite are also addressed. Adsorption of MoO4(2-) and MoS4(2-) on pyrite and goethite is in general well described by a Langmuir model at low pH; the extent of sorption is a function of pH and the surface loading. Maximum sorption is observed in the acidic pH range (pH<5) at low surface loading. The adsorption of molybdenum (micromol g(-1)) depends upon Mo species and on the type of iron mineral following the order: MoS4(2-)-goethite > MoO4(2-)-goethite > MoS4(2-)-pyrite > MoO4(2-)-pyrite. Phosphate appears to compete strongly with MoO4(2-) and MoS4(2-) for the sorption sites of pyrite and goethite. The strength of the phosphate competitive effect follows the sequence of MoO4(2-)-goethite approximately = MoO4(2-)-pyrite > MoS4(2-)-pyrite > MoS4(2-)-goethite. Silicate and sulfate have a negligible effect on the sorption of MoO4(2-) and MoS4(2-). The preferred adsorption by iron mineral of MoS4(2-), as well as its behavior in the presence of competitive anions suggests that tetrathiomolybdate species may be an ultimate reservoir and may control Mo enrichment in the sediments.     

Modeling of air sparging of VOC-contaminated soil columns

Air sparging is a remediation technology currently being applied for the restoration of sites contaminated with volatile organic compounds (VOCs). Attempts have been made by various researchers to model the fate of VOCs in the gas and liquid phase during air sparging. In this study, a radial diffusion model with an air–water mass transfer boundary condition was developed and applied for the prediction of VOC volatilization from air sparging of contaminated soil columns. The approach taken was to use various parameters such as mass transfer coefficients and tortuosity factors determined previously in separate experiments using a single air channel apparatus and applying these parameters to a complex system with many air channels. Incorporated in the model, is the concept of mass transfer zone (MTZ) where diffusion of VOCs in this zone was impacted by the volatilization of VOCs at the air–water interface but with negligible impact outside the zone. The model predicted fairly well the change in the VOC concentrations in the exhaust air, the final average aqueous VOC concentration, and the total mass removed. The predicted mass removal was within 1% to 20% of the actual experimental mass removed. The results of the model seemed to suggest that air-sparged soil columns may be modeled as a composite of individual air channels surrounded by a MTZ. For a given air flow rate and air saturation, the VOC removal was found to be inversely proportional to the radius of the air channel. The approach taken provided conceptual insights on mass transfer processes during air sparging operations.     

A simultaneous equations model of crash frequency by collision type for rural intersections

Safety at roadway intersections is of significant interest to transportation professionals due to the large number of intersections in transportation networks, the complexity of traffic movements at these locations that leads to large numbers of conflicts, and the wide variety of geometric and operational features that define them. A variety of collision types including head-on, sideswipe, rear-end, and angle crashes occur at intersections. While intersection crash totals may not reveal a site deficiency, over exposure of a specific crash type may reveal otherwise undetected deficiencies. Thus, there is a need to be able to model the expected frequency of crashes by collision type at intersections to enable the detection of problems and the implementation of effective design strategies and countermeasures. Statistically, it is important to consider modeling collision type frequencies simultaneously to account for the possibility of common unobserved factors affecting crash frequencies across crash types. In this paper, a simultaneous equations model of crash frequencies by collision type is developed and presented using crash data for rural intersections in Georgia. The model estimation results support the notion of the presence of significant common unobserved factors across crash types, although the impact of these factors on parameter estimates is found to be rather modest.     

Effect of the zero-tolerance drinking and driving law on mortality due to road traffic accidents according to the type of victim,sex, and age in Rio de Janeiro,Brazil: An interrupted time series study

Objective: The objective of this study was to estimate the effect of the Brazilian zero-tolerance drinking and driving law on mortality rates due to road traffic accidents according to the type of victim, sex, and age.

Methods: An interrupted time series design was used to compare yearly mortality rates due to road traffic accidents in Rio de Janeiro, Brazil, before and after the zero-tolerance drinking and driving law came into effect on June 19, 2008. Yearly mortality rates were compared according to the type of victim: pedestrian, cyclist, motorcyclist, and vehicle occupant. We used the Prais-Winsten procedure of autoregression in the analysis of time series; the outcome of this analysis was the annual percentage change in the rates. Overall and stratified analyses were conducted to investigate whether the zero-tolerance drinking and driving law may have had a distributional effect on mortality rates due to road traffic accidents depending on sex and age group; a significance level of P < .01 was accepted.

Results: From 1999 to 2016, there were 15,629 deaths due to road traffic accidents in Rio de Janeiro. The effect of the zero-tolerance drinking and driving law on overall mortality rates due to road traffic accidents in Rio de Janeiro was not statistically significant. However, among cyclists and motorcyclists aged ≥60 years and among pedestrians of both sexes and aged ≥20 years, the effect of the zero-tolerance drinking and driving law was to decrease mortality due to road traffic accidents at a yearly rate.

Conclusion: There is evidence of reduced mortality rates due to road traffic accidents among cyclists and motorcyclists aged ≥60 years and among pedestrians of both sexes aged ≥20 years in the second major Brazilian capital 9 years after the zero-tolerance drinking and driving law was adopted.     

Genetically informed captive breeding of hybrids of an extinct species of Galapagos tortoise

Hybridization poses a major challenge for species conservation because it threatens both genetic integrity and adaptive potential. Yet, hybridization can occasionally offer unprecedented opportunity for species recovery if the genome of an extinct taxon is present among living hybrids such that selective breeding could recapture it. We explored the design elements for establishing a captive-breeding program for Galapagos tortoises (Chelonoidis spp.) built around individuals with admixed ancestry involving an extinct species. The target individuals were hybrids between the extinct species from Floreana Island, C. niger, and an extant species, C. becki, which were recently found in the endemic range of C. becki, from Wolf Volcano on Isabela Island. We combined genotypic data from 35 tortoises with high ancestry from C. niger with forward-in-time simulations to explore captive breeding strategies that maximized overall genetic diversity and ancestry from C. niger while accommodating resource constraints, species biology, and the urgency to return tortoises to Floreana Island for facilitating ecosystem restoration. Overall genetic diversity was maximized when in the simulation tortoises were organized in relatively small breeding groups. Substantial amounts of the C. niger genome were captured despite limited resources available for selectively breeding tortoises in captivity. Genetic diversity was maximized when captive-bred offspring were released to the wild rather than being used as additional breeders. Our results provide genetic-based and practical guidance on the inclusion of hybrids with genomic representation from extinct taxa into species restoration programs and informs the ongoing debate on the value of hybrids in biodiversity conservation.     

A rapid and quantitative mass spectrometry method for determining the concentration of acylcarnitines and aminoacids in amniotic fluid

We describe a quantitative, rapid, sensitive and reproducible tandem mass spectrometry (MSMS) method for the one-step detection of aminoacid (AAs) and acylcarnitine (ACs) concentrations in amniotic fluid. This technology is quicker and more sensitive than other methods used to date since it is possible to determine very low AA and AC concentrations in samples simultaneously in a single run. The high degree of automation allows a large number of pregnancies to be screened for metabolic defects in a very short time. Copyright © 2001 John Wiley & Sons, Ltd.