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Simulated exposure to severe acute respiratory syndrome coronavirus 2 in the environment was demonstrated based on the actual coronavirus disease 2019 cluster occurrence in an office, with a projected risk considering the likely transmission pathways via aerosols and fomites. A total of 35/85 occupants were infected, with the attack rate in the first stage as 0.30. It was inferred that the aerosol transmission at long‐range produced the cluster at virus concentration in the saliva of the infected cases on the basis of the simulation, more than 108 PFU mL−1. Additionally, all wearing masks effectiveness was estimated to be 61%–81% and 88%–95% reduction in risk for long‐range aerosol transmission in the normal and fit state of the masks, respectively, and a 99.8% or above decline in risk of fomite transmission. The ventilation effectiveness for long‐range aerosol transmission was also calculated to be 12%–29% and 36%–66% reductions with increases from one air change per hour (ACH) to two ACH and six ACH, respectively. Furthermore, the virus concentration reduction in the saliva to 1/3 corresponded to the risk reduction for long‐range aerosol transmission by 60%–64% and 40%–51% with and without masks, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT To characterize potential air pollution issues related to recycling facilities of waste plastics, volatile organic compounds (VOCs) emitted from melted virgin and waste plastics pellets were analyzed. In this [...]

Abstract Background The gene composition, gene order and structure of the mitochondrial genome are remarkably stable across bilaterian animals. Lice (Insecta: Phthiraptera) are a major exception to this genomic stability in that the canonical single chromosome with 37 genes found in almost all other bilaterians has been lost in multiple lineages in favour of multiple, minicircular chromosomes with less than 37 genes on each chromosome. Results Minicircular mt genomes are found in six of the ten louse species examined to date and three types of minicircles were identified: heteroplasmic minicircles which coexist with full sized mt genomes (type 1); multigene chromosomes with short, simple control regions, we infer that the genome consists of several such chromosomes (type 2); and multiple, single to three gene chromosomes with large, complex control regions (type 3). Mapping minicircle types onto a phylogenetic tree of lice fails to show a pattern of their occurrence consistent with an evolutionary series of minicircle types. Analysis of the nuclear-encoded, mitochondrially-targetted genes inferred from the body louse, Pediculus, suggests that the loss of mitochondrial single-stranded binding protein (mtSSB) may be responsible for the presence of minicircles in at least species with the most derived type 3 minicircles (Pediculus, Damalinia). Conclusions Minicircular mt genomes are common in lice and appear to have arisen multiple times within the group. Life history adaptive explanations which attribute minicircular mt genomes in lice to the adoption of blood-feeding in the Anoplura are not supported by this expanded data set as minicircles are found in multiple non-blood feeding louse groups but are not found in the blood-feeding genus Heterodoxus. In contrast, a mechanist explanation based on the loss of mtSSB suggests that minicircles may be selectively favoured due to the incapacity of the mt replisome to synthesize long replicative products without mtSSB and thus the loss of this gene lead to the formation of minicircles in lice.

High ozone concentrations often exist under the reduced pressure conditions observed in aircraft cabins during flight. In this study, we measured the concentrations of the products obtained from the reaction of ozone with limonene in a simulated aircraft cabin environment (i.e., vacuum chamber at approximately 70 kPa). The concentration of total volatile organic compounds increased under reduced pressure when compared to that under atmospheric pressure, whereas the ozone concentration decreased during the hour after limonene was injected into the chamber. These changes can be partially explained by the increased evaporation of limonene under reduced pressure. With respect to secondary products, a decrease in particulate matter was observed under reduced pressure for an initial ozone concentration of 0.4–0.5 mg/m3. In contrast, the effects of reduced pressure on the concentrations of gaseous products, such as formaldehyde and limonene oxide, were small when the initial ozone concentration was approximately 0.3 mg/m3. These results indicate that the reaction between limonene and ozone under reduced pressure is similar to that occurring under atmospheric pressure. Image 1 • In aircraft cabins during flight, ozone often exists under the reduced pressure. • We simulated ozone and limonene reaction under reduced pressure in a chamber. • Particulate matter generation inhibited under reduced pressure. • Effects of reduced pressure on the concentration of gaseous products were minor. • Ozone/limonene reaction was similar under atmospheric and reduced pressures. [ABSTRACT FROM AUTHOR]

Simulated exposure to severe acute respiratory syndrome coronavirus 2 in the environment was demonstrated based on the actual coronavirus disease 2019 cluster occurrence in an office, with a projected risk considering the likely transmission pathways via aerosols and fomites. A total of 35/85 occupants were infected, with the attack rate in the first stage as 0.30. It was inferred that the aerosol transmission at long-range produced the cluster at virus concentration in the saliva of the infected cases on the basis of the simulation, more than 10 8  PFU mL -1 . Additionally, all wearing masks effectiveness was estimated to be 61%-81% and 88%-95% reduction in risk for long-range aerosol transmission in the normal and fit state of the masks, respectively, and a 99.8% or above decline in risk of fomite transmission. The ventilation effectiveness for long-range aerosol transmission was also calculated to be 12%-29% and 36%-66% reductions with increases from one air change per hour (ACH) to two ACH and six ACH, respectively. Furthermore, the virus concentration reduction in the saliva to 1/3 corresponded to the risk reduction for long-range aerosol transmission by 60%-64% and 40%-51% with and without masks, respectively., (© 2023 The Authors. Risk Analysis published by Wiley Periodicals LLC on behalf of Society for Risk Analysis.)