Simulated downwind coal combustion emissions for laboratory inhalation exposure atmospheres.

Exposure atmospheres for rodent inhalation toxicology studies were generated to enable the evaluation of biological responses to a simulated downwind coal combustion atmosphere. A composition representing a single test case of emissions components as they may exist tens to hundreds of miles from a coal-fired power plant was developed. The particulate matter (PM) was 99% sulfate (partially neutralized) and 1% ash. Sulfate was present in equimolar concentrations to sulfur dioxide (SO2). Gaseous nitrogen species included nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid (HNO3). At the high-exposure level, the gaseous species target concentrations were 0.2 ppm SO2, 0.6 ppm NO, 0.3 ppm NO2, and 0.1 ppm HNO3. The test atmosphere was produced by combining effluent from a laboratory coal combustor with sulfate generated through an evaporation-condensation generator. These atmospheres were used to conduct inhalation toxicology studies that have been previously reported.

Only two out of five articles by New Zealand researchers are free-to-access: a multiple API study of access, citations, cost of Article Processing Charges (APC), and the potential to increase the proportion of open access.

We studied journal articles published by researchers at all eight New Zealand universities in 2017 to determine how many were freely accessible on the web. We wrote software code to harvest data from multiple sources, code that we now share to enable others to reproduce our work on their own sample set. In May 2019, we ran our code to determine which of the 2017 articles were open at that time and by what method; where those articles would have incurred an Article Processing Charge (APC) we calculated the cost if those charges had been paid. Where articles were not freely available we determined whether the policies of publishers in each case would have allowed deposit in a non-commercial repository (Green open access). We also examined citation rates for different types of access. We found that, of our 2017 sample set, about two out of every five articles were freely accessible without payment or subscription (41%). Where research was explicitly said to be funded by New Zealand's major research funding agencies, the proportion was slightly higher at 45%. Where open articles would have incurred an APC we estimated an average cost per article of USD1,682 (for publications where all articles require an APC, that is, Gold open access) and USD2,558 (where APC payment is optional, Hybrid open access) at a total estimated cost of USD1.45m. Of the paid options, Gold is by far more common for New Zealand researchers (82% Gold, 18% Hybrid). In terms of citations, our analysis aligned with previous studies that suggest a correlation between publications being freely accessible and, on balance, slightly higher rates of citation. This is not seen across all types of open access, however, with Diamond OA achieving the lowest rates. Where articles were not freely accessible we found that a very large majority of them (88% or 3089 publications) could have been legally deposited in an institutional repository. Similarly, only in a very small number of cases had a version deposited in the repository of a New Zealand university made the difference between the publication being freely accessible or not (125 publications). Given that most New Zealand researchers support research being open, there is clearly a large gap between belief and practice in New Zealand's research ecosystem.

Inhalation exposure systems for the development of rodent models of sulfur mustard-induced pulmonary injury.

Sulfur mustard (SM) is a chemical threat agent for which its effects have no current treatment. Due to the ease of synthesis and dispersal of this material, the need to develop therapeutics is evident. The present manuscript details the techniques used to develop SM laboratory exposure systems for the development of animal models of pulmonary injury. These models are critical for evaluating SM injury and developing therapeutics against that injury. Iterative trials were conducted to optimize a lung injury model. The resulting pathology was used as a guide, with a goal of effecting homogeneous and diffuse lung injury comparable to that of human injury. Inhalation exposures were conducted by either nose-only inhalation or intubated inhalation. The exposures were conducted to either directly vaporized SM or SM that was nebulized from an ethanol solution. Inhalation of SM by nose-only inhalation resulted in severe nasal epithelial degeneration and minimal lung injury. The reactivity of SM did not permit it to transit past the upper airways to promote lower airway injury. Intratracheal inhalation of SM vapors at a concentration of 5400 mg x min/m(3) resulted in homogeneous lung injury with no nasal degeneration.

Generation and characterization of gasoline engine exhaust inhalation exposure atmospheres.

Exposure atmospheres for a rodent inhalation toxicology study were generated from the exhaust of a 4.3-L gasoline engine coupled to a dynamometer and operated on an adapted California Unified Driving Cycle. Exposure levels were maintained at three different dilution rates. One chamber at the lowest dilution had particles removed by filtration. Each exposure atmosphere was characterized for particle mass, particle number, particle size distribution, and detailed chemical speciation. The majority of the mass in the exposure atmospheres was gaseous carbon monoxide, nitrogen oxides, and volatile organics, with small amounts of particle-bound carbon/ions and metals. The atmospheres varied according to the cycle, with the largest spikes in volatile organic and inorganic species shown during the "cold start" portion of the cycle. Ammonia present from the exhaust and rodents interacted with the gasoline exhaust to form secondary inorganic particles, and an increase in exhaust resulted in higher proportions of secondary inorganics as a portion of the total particle mass. Particle size had a median of 10-20 nm by number and approximately 150 nm by mass. Volatile organics matched the composition of the fuel, with large proportions of aliphatic and aromatic hydrocarbons coupled to low amounts of oxygenated organics. A new measurement technique revealed organics reacting with nitrogen oxides have likely resulted in measurement bias in previous studies of combustion emissions. Identified and measured particle organic species accounted for about 10% of total organic particle mass and were mostly aliphatic acids and polycyclic aromatic hydrocarbons.

Generation and characterization of four dilutions of diesel engine exhaust for a subchronic inhalation study.

Exposure atmospheres for a rodent inhalation toxicology study were generated from the exhaust of a 2000 Cummins ISB 5.9L diesel engine coupled to a dynamometer and operated on a slightly modified heavy-duty Federal Test Procedure cycle. Exposures were conducted to one clean air control and four diesel exhaust levels maintained at four different dilution rates (300:1, 100:1, 30:1, 10:1) that yielded particulate mass concentrations of 30, 100, 300, and 1000 microg/m3. Exposures at the four dilutions were characterized for particle mass, particle size distribution (reported elsewhere), detailed chemical speciation of gaseous, semivolatile, and particle-phase inorganic and organic compounds. Target analytes included metals, inorganic ions and gases, organic and elemental carbon, alkanes, alkenes, aromatic and aliphatic acids, aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH), oxygenated PAH, nitrogenated PAH, isoprenoids, carbonyls, methoxyphenols, sugar derivatives, and sterols. The majority of the mass of material in the exposure atmospheres was gaseous nitrogen oxides and carbon monoxide, with lesser amounts of volatile organics and particle mass (PM) composed of carbon (approximately 90% of PM) and ions (approximately 10% of PM). Measured particle organic species accounted for about 10% of total organic particle mass and were mostly alkanes and aliphatic acids. Several of the components in the exposure atmosphere scaled in concentration with dilution but did not scale precisely with the dilution rate because of background from the rodents and scrubbed dilution air, interaction of animal derived emissions with diesel exhaust components, and day-to-day variability in the output of the engine. Rodent-derived ammonia reacted with exhaust to form secondary inorganic particles (at different rates dependent on dilution), and rodent respiration accounted for volatile organics (especially carbonyls and acids) in the same range as the diesel exhaust at the lowest exhaust exposure concentrations. Day-to-day variability in the engine output was implicated partially for differences of several components, including some of the particle bound organics. Though these observations have likely occurred in nearly all inhalation exposure atmospheres that contain complex mixtures of material, the speciations conducted here illustrate many of them for the first time.