Assessment of thoron contribution to indoor radon exposure in Canada

From 2007 to 2013, simultaneous radon (222Rn) and thoron (220Rn) measurements were conducted in a total of 3534 residential homes in 34 metropolitan areas covering 71% of the Canadian population. While radon levels were above the detector’s detection limit in almost all homes, thoron concentrations were measurable in only 1738 homes. When analysis was limited to homes where thoron concentrations exceeded the detection limit, a pooled analysis confirmed that thoron is log-normally distributed in the indoor environment, and the distribution was characterized by a population-weighted geometric mean of 13 Bq/m3 and a geometric standard deviation of 1.89. Thoron contribution to indoor radon dose varied widely, ranging from 1.3 to 32% geographically. This study indicated that on average, thoron contributes 4% of the radiation dose due to total indoor radon exposure (222Rn and 220Rn) in Canada.

Modeled Respiratory Tract Deposition of Aerosolized Oil Diluents Used in Δ9-THC-Based Electronic Cigarette Liquid Products

Electronic cigarette, or vaping, products (EVP) heat liquids (“e-liquids”) that contain substances (licit or illicit) and deliver aerosolized particles into the lungs. Commercially available oils such as Vitamin-E-acetate (VEA), Vitamin E oil, coconut, and medium chain triglycerides (MCT) were often the constituents of e-liquids associated with an e-cigarette, or vaping, product use-associated lung injury (EVALI). The objective of this study was to evaluate the mass-based physical characteristics of the aerosolized e-liquids prepared using these oil diluents. These characteristics were particle size distributions for modeling regional respiratory deposition and puff-based total aerosol mass for estimating the number of particles delivered to the respiratory tract. Four types of e-liquids were prepared by adding terpenes to oil diluents individually: VEA, Vitamin E oil, coconut oil, and MCT. A smoking machine was used to aerosolize each e-liquid at a predetermined puff topography (volume of 55 ml for 3 s with 30-s intervals between puffs). A cascade impactor was used to collect the size-segregated aerosol for calculating the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD). The respiratory deposition of EVP aerosols on inhalation was estimated using the Multiple-Path Particle Dosimetry model. From these results, the exhaled fraction of EVP aerosols was calculated as a surrogate of secondhand exposure potential. The MMAD of VEA (0.61 μm) was statistically different compared to MCT (0.38 μm) and coconut oil (0.47 μm) but not to Vitamin E oil (0.58 μm); p < 0.05. Wider aerosol size distribution was observed for VEA (GSD 2.35) and MCT (GSD 2.08) compared with coconut oil (GSD 1.53) and Vitamin E oil (GSD 1.55). Irrespective of the statistical differences between MMADs, dosimetry modeling resulted in the similar regional and lobular deposition of particles for all e-liquids in the respiratory tract. The highest (~0.08 or more) fractional deposition was predicted in the pulmonary region, which is consistent as the site of injury among EVALI cases. Secondhand exposure calculations indicated that a substantial amount of EVP aerosols could be exhaled, which has potential implications for bystanders. The number of EVALI cases has declined with the removal of VEA; however, further research is required to investigate the commonly available commercial ingredients used in e-liquid preparations.

AUG-3387, a Human-Derived Monoclonal Antibody Neutralizes SARS-CoV-2 Variants and Reduces Viral Load from Therapeutic Treatment of Hamsters In Vivo

Infections from the SARS-CoV-2 virus have killed over 4.6 million people since it began spreading through human populations in late 2019. In order to develop a therapeutic or prophylactic antibody to help mitigate the effects of the pandemic, a human monoclonal antibody (mAb) that binds to the SARS-CoV-2 spike protein was isolated from a convalescent patient following recovery from COVID-19 disease. This mAb, designated AUG-3387, demonstrates a high affinity for the spike protein of the original viral strains and all variants tested to date. In vitro pseudovirus neutralization and SARS-CoV-2 neutralization activity has been demonstrated in vitro. In addition, a dry powder formulation has been prepared using a Thin Film Freezing (TFF) process that exhibited a fine particle fraction (FPF) of 50.95 ± 7.69% and a mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of 3.74 ± 0.73 μm and 2.73 ± 0.20, respectively. The dry powder is suitable for delivery directly to the lungs of infected patients using a dry powder inhaler device. Importantly, AUG-3387, administered as a liquid by intraperitoneal injection or the dry powder formulation delivered intratracheally into Syrian hamsters 24 hours after intranasal SARS-CoV-2 infection, demonstrated a dose-dependent reduction in the lung viral load of the virus. These data suggest that AUG-3387 formulated as a dry powder demonstrates potential to treat COVID-19.

Factors Associated with Blood Lead Levels in Children in Shenyang, China: A Cross-Sectional Study

Background: Although blood lead levels in children are gradually decreasing, low-concentration lead exposure can still exert adverse effects. We studied the factors that affect blood lead levels in children in Shenyang, China.Methods: We conducted a cross-sectional study by administering structured questionnaires on family demographics and food intake. The concentrations of lead in venous blood were determined by graphite furnace atomic absorption spectrometry.Results: A total of 273 children aged 1–6 years were enrolled. The geometric mean (geometric standard deviation) of blood lead levels was 24.94 (12.7) μg/L in boys and 23.75 (11.34) μg/L in girls. The prevalence of blood lead levels of ≥50 μg/L was 5.13% and was mainly observed in children aged under 3 years. Frequent hand washing was protective against blood lead levels ≥20 μg/L (adjusted odds ratio: 0.428, 95% confidence interval: 0.238–0.768). Consumption of puffed grains and eggs had an adjusted odds ratio for blood lead levels ≥20 μg/L of 1.714 (1.012–2.901) and 1.787 (1.000–3.192), respectively.Conclusions: In comparison with values recorded 20 years ago, blood lead levels in young children are gradually decreasing in Shenyang. Consumption of puffed grains and eggs is a source of lead. Frequent hand washing may be protective against high blood lead levels.

Control of the Health Risk of Radon Exposure in the Republic of Moldova

The paper presents the results of a national radon survey conducted in the context of the Republic of Moldova. The study included about 2500 homes of different types, located in urban and rural localities in different areas of the country. The RADTRAK2 detectors kindly provided by the RADONOVA laboratory, Uppsala, Sweden, for the MOL9007 project funded by the International Atomic Energy Agency (IAEA) have been used. The exposure period was 90 days. The measured radon concentrations are the following: the average (±standard deviation) 252.8 ± 215.9 Bq/m3; the range (minimum–maximum) 10–1480 Bq/m3; the median 200 Bq/m3 and the geometric mean (± geometric standard deviation) 158.5 ± 3.0 Bq/m3. The results of the study allowed mapping indoor radon and identifying localities with increased radon concentrations. In order to reduce the high radon concentrations in places recording >300 Bq/m3, appropriate measures have been proposed according to the legislation in force. The cluster analysis showed positive links between the radon concentration in dwellings and the incidence of respiratory diseases, especially the bronchopulmonary cancer in the country.

Feasibility study: Proposed alternative to N95 respirator during the personal protective equipment shortage from COVID-19 pandemic

Introduction: Having an adequate supply of personal protective equipment during the COVID-19 pandemic has been a constant challenge for hospitals across the United States. In the event of shortages, our assembled mask might offer noninferior protection compared to an N95 respirator. Objective: To study the ability of an assembled mask to pass a quantitative fit testing.Methods: We conducted a feasibility study at the Oklahoma City Veteran Affairs Health Care System. Volunteers were fitted with an assembled mask made of either a Hans Rudolph half-face mask or a Respironics Performax full-face mask, attached to an Iso-Gard HEPA light Filter 28022 through a Performax SE elbow hinge. Quantitative fit testing was conducted using the Occupation Safety and Health Administration fit testing protocol. The primary outcome was the percentage of participants who pass the quantitative fit test. Secondary outcomes included the overall fit factor (FF), average FF for different exercises, changes in pulse oximetry and endtidal CO2 at 0 and 15 minutes, willingness to use the mask, and visibility assessment.Results: Twenty participants completed the study, and all (100 percent) passed the quantitative fit testing. The overall FF had a geometric mean of 2,317 (range: 208-16,613) and a geometric standard deviation of 3.8. The lowest FF was recorded while the subjects were talking. Between time 0 and 15 minutes, there was no clinically significant change in pulse oximetry and end-tidal CO2 levels. Most participants reported “very good” visibility and were “highly likely” to use the Hans Rudolph half-face mask in the case of shortage.Conclusion: Our assembled respirator offers noninferior protection to N95 respirators in the setting of hypothetical protective equipment shortage.

Current diesel engine exhaust exposure in the Ontario construction industry

Introduction: Diesel engine exhaust (DEE) is a known carcinogen and a common occupational exposure in Canada, particularly within construction. The use of diesel-powered equipment in the construction industry is widespread, but little is known about DEE exposures and occupational disease in this work setting. The objective of this study was to characterize and identify key determinants of DEE exposure at construction sites in Ontario. Methods: Diesel particulate matter (DPM) measurements were taken from workers employed on seven infrastructure construction worksites in Ontario. Full-shift personal air samples were collected from workers using a constant-flow pump and SKC aluminum cyclone with 37-mm quartz fibre filters in an open-faced cassette. Samples were analyzed for elemental carbon (EC), a surrogate of DEE exposure, following NIOSH method 5040. Exposures were compared to recommended health-based limits, including the Dutch Expert Committee on Occupational Safety (DECOS) limit (1.03µg/m3 respirable EC) and the Finnish Institute of Occupational Health (FIOH) recommendation (5µg/m3 respirable EC). A determinants of exposure model was constructed. Results: In total, 126 DPM samples were collected, ranging from <0.47-52.58µg/m3 with a geometric mean (GM) of 4.23µg/m3 (geometric standard deviation (GSD)=3.05). Overall, 44.8% of samples exceeded the FIOH limit, mostly within underground worksites (93.5%), and 88.8% exceeded the DECOS limit. Underground workers (GM=13.20µg/m3, GSD=1.83) had exposures approximately 4-times higher than below grade workers (GM=3.56µg/m3, GSD=1.94) and 9-times higher than aboveground workers (GM=1.49µg/m3, GSD=1.75). Work grade, enclosed cabs, and seasonality were identified as the major determinants of exposure. Conclusions: This study provides a better understanding of current DPM exposure in Canadian construction. Most exposures were above recommended health-based limits, signifying a need to further reduce DPM levels in construction. These results can inform a hazard reduction strategy including a new occupational exposure limit and targeted intervention/control measures to reduce DPM exposure and the burden of occupational cancer.

Sorrentina Peninsula: Geographical Distribution of the Indoor Radon Concentrations in Dwellings—Gini Index Application

The radon isotope (222Rn, half-life 3.8 days) is a radioactive byproduct of the 238U decay chain. Because radon is the second biggest cause of lung cancer after smoking, dense maps of indoor radon concentration are required to implement effective locally based risk reduction strategies. In this regard, we present an innovative method for the construction of interpolated maps (kriging) based on the Gini index computation to characterize the distribution of Rn concentration. The Gini coefficient variogram has been shown to be an effective predictor of radon concentration inhomogeneity. It allows for a better constraint of the critical distance below which the radon geological source can be considered uniform, at least for the investigated length scales of variability; it also better distinguishes fluctuations due to environmental predisposing factors from those due to random spatially uncorrelated noise. This method has been shown to be effective in finding larger-scale geographical connections that can subsequently be connected to geological characteristics. It was tested using real dataset derived from indoor radon measurements conducted in the Sorrentina Peninsula in Campania, Italy. The measurement was carried out in different residences using passive detectors (CR-39) for two consecutive semesters, beginning in September–November 2019 and ending in September–November 2020, to estimate the yearly mean radon concentration. The measurements and analysis were conducted in accordance with the quality control plan. Radon concentrations ranged from 25 to 722 Bq/m3 before being normalized to ground level, and from 23 to 933 Bq/m3 after being normalized, with a geometric mean of 120 Bq/m3 and a geometric standard deviation of 1.35 before data normalization, and 139 Bq/m3 and a geometric standard deviation of 1.36 after data normalization. Approximately 13% of the tests conducted exceeded the 300 Bq/m3 reference level set by Italian Legislative Decree 101/2020. The data show that the municipalities under investigation had no influence on indoor radon levels. The geology of the monitored location is interesting, and because soil is the primary source of Rn, risk assessment and mitigation for radon exposure cannot be undertaken without first analyzing the local geology. This research examines the spatial link among radon readings using the mapping based on the Gini method (kriging).

Selected Physical and Flowability Properties of Evolving Distillers Dried Grains With Solubles (DDGS)

With the rapid development of the ethanol industry over the past few decades, research on distillers dried grains with solubles (DDGS), its main coproduct, has increased in recent years. However, research about the basic properties of DDGS lacks comprehensiveness. This study examined 16 DDGS samples from 10 ethanol plants in the Midwest U.S., and used standard laboratory methods to measure a series of physical and flowability properties. Results showed an average moisture content of 8.69% (w. b.), water activity of 0.55, angle of repose of 48.04°, shear strength of 0.0324 kg/cm2, geometric mean diameter (dgw) of 0.74 mm, geometric standard deviation (Sgw) of 1.72 mm, loose bulk density of 483.9 kg/m3, packed bulk density of 568.5 kg/m3, Hunter L of 56.71, Hunter a of 13.85, and Hunter b of 46.51. This study represents a step toward a more complete understanding of DDGS, and how various properties change as production practices evolve in the ethanol industry.