Assessment of fate of respiratory droplets and effectiveness of different air cleaners during outpatient consultation.

Outpatient departments are open daily to receive patients for consultation. Physicians face a potential risk of infection when diagnosing patients with respiratory infections. This study investigated the fate of droplets exhaled by patient speaking during consultation in a hospital consulting room (CR) using numerical simulations.

A model of the spatiotemporal distribution of ozone-squalene reaction and ozonolysis by-products from human body.

Emissions of ozone and its by-products from ozonolysis on human surfaces lead to indoor air pollution. However, the spatiotemporal distribution of such emissions in indoor environments remains unclear, which may introduce bias when assessing human exposure to ozone and ozonolysis byproducts. This study developed a computational fluid dynamics model to describe the physical and chemical processes involved in the emission of ozone-dependent volatile organic compounds from the human body.

Air disinfection performance of upper-room ultraviolet germicidal irradiation (UR-UVGI) system in a multi-compartment dental clinic.

Multi-compartment dental clinics present significant airborne cross-infection risks. Upper-room ultraviolet germicidal irradiation (UR-UVGI) system have shown promise in preventing airborne pathogens, but its available application data are insufficient in multi-compartment dental clinics. Therefore, the UR-UVGI system's performance in a multi-compartment dental clinic was comprehensively evaluated in this study.

Spatial distribution of bioaerosols and evaluation of four ventilation method on controlling their diffusion in a typical enhanced biosafety level 2 laboratory.

Biosafety laboratories are critical in many fields. However, experimenters associated the infection risk from biological aerosols. In this study, by conducting experiments on the release and collection of bioaerosols within a typical BSL-2 + laboratory, the spatial distribution of bioaerosols was tracked.

Investigating the spatial distribution of volatile organic compounds in aircraft cabins from various emission sources.

Volatile organic compounds (VOCs) significantly affect the air quality in aircraft cabins, consequently affecting passenger health and comfort. Although VOC emission sources and their contributions have been studied extensively, the distribution characteristics of VOCs originating from diverse sources within cabins have received limited attention, and the correlation between VOC sources and concentrations in passenger breathing zones remains largely unexplored. To fill this knowledge gap, the concentration field of VOCs was investigated using a computational fluid dynamics model, and the results were experimentally validated in a typical single-aisle aircraft cabin with seven seat rows.

Reducing airborne transmission of SARS-CoV-2 by an upper-room ultraviolet germicidal irradiation system in a hospital isolation environment.

Upper-room ultraviolet germicidal irradiation (UVGI) technology can potentially inhibit the transmission of airborne disease pathogens. There is a lack of quantitative evaluation of the performance of the upper-room UVGI for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) airborne transmission under the combined effects of ventilation and UV irradiation. Therefore, this study aimed to explore the performance of the upper-room UVGI system for reducing SARS-CoV-2 virus transmission in a hospital isolation environment.

The impact of high background particle concentration on the spatiotemporal distribution of Serratia marcescens bioaerosol.

Airborne transmission is a well-established mode of dissemination for infectious diseases, particularly in closed environments. However, previous research has often overlooked the potential impact of background particle concentration on bioaerosol characteristics. We compared the spatial and temporal distributions of bioaerosols under two levels of background particle concentration: heavily polluted (150-250 μg/m) and excellent (0-35 μg/m) in a typical ward.

Complex evolutionary interactions in multiple populations.

In competitive settings that entail several populations, individuals often engage in intra- and interpopulation interactions that determine their fitness and evolutionary success. With this simple motivation, we here study a multipopulation model where individuals engage in group interactions within their own population and in pairwise interactions with individuals from different populations. We use the evolutionary public goods game and the prisoner's dilemma game to describe these group and pairwise interactions, respectively.

Modeling the infection risk and emergency evacuation from bioaerosol leakage around an urban vaccine factory.

Mounting interest in modeling outdoor diffusion and transmission of bioaerosols due to the prevalence of COVID-19 in the urban environment has led to better knowledge of the issues concerning exposure risk and evacuation planning. In this study, the dispersion and deposition dynamics of bioaerosols around a vaccine factory were numerically investigated under various thermal conditions and leakage rates. To assess infection risk at the pedestrian level, the improved Wells-Riley equation was used.

Estimating the restraint of SARS-CoV-2 spread using a conventional medical air-cleaning device: Based on an experiment in a typical dental clinical setting.

Objectives: Droplets or aerosols loaded with SARS-CoV-2 can be released during breathing, coughing, or sneezing from COVID-19-infected persons. To investigate whether the most commonly applied air-cleaning device in dental clinics, the oral spray suction machine (OSSM), can provide protection to healthcare providers working in clinics against exposure to bioaerosols during dental treatment.

Method: In this study, we measured and characterized the temporal and spatial variations in bioaerosol concentration and deposition with and without the use of the OSSM using an experimental design in a dental clinic setting.

Transmission characteristics of infectious pathogen-laden aerosols in a negative-pressure operating room.

The infectious pathogen-laden aerosols generated by infected patients have a significant impact on the safety of surgical staff in highly clean negative-pressure operating rooms. Understanding the transmission characteristics of infectious pathogen-laden aerosols is therefore essential. Therefore, in this study, we conducted experiments in a full-size negative-pressure operating room, and the Phi-X174 phage was used as a bioaerosol release source to investigate the migration and deposition of bioaerosols.

A model to evaluate ozone distribution and reaction byproducts in aircraft cabin environments.

Ozone and byproducts of ozone-initiated reactions are among the primary pollutants in aircraft cabins. However, investigations of the spatial distribution and reaction mechanisms of these pollutants are insufficient. This study established a computational fluid dynamics-based model to evaluate ozone and byproduct distribution, considering ozone reactions in air, adsorption onto surfaces, and byproduct desorption from surfaces.

Bioaerosol distribution characteristics and potential SARS-CoV-2 infection risk in a multi-compartment dental clinic.

Dental clinics have a potential risk of infection, particularly during the COVID-19 pandemic. Multi-compartment dental clinics are widely used in general hospitals and independent clinics. This study utilised computational fluid dynamics to investigate the bioaerosol distribution characteristics in a multi-compartment dental clinic through spatiotemporal distribution, working area time-varying concentrations, and key surface deposition.

Droplet aerosols transportation and deposition for three respiratory behaviors in a typical negative pressure isolation ward.

Negative pressure isolation wards could provide safety for health care workers (HCWs) and patients infected with SARS-CoV-2. However, respiratory behavior releases aerosols containing pathogens, resulting in a potential risk of infection for HCWs. In this study, the spatiotemporal distribution of droplet aerosols in a typical negative pressure isolation ward was investigated using a full-scale experiment.

Carbon dioxide in passenger cabins: Spatial temporal characteristics and 30-year trends.

Carbon dioxide (CO ) is an important environmental parameter in aircraft cabins. To understand the most recent, real-time CO concentration levels and their key influencing factors in aircraft cabins, we conducted in-flight measurements of 52 randomly selected commercial flights with different aircraft types and durations from August 2017 to August 2019. The spatial temporal characteristics of CO concentrations on board were analyzed and summarized.

A Novel Tissue-Based Liver-Kidney-on-a-Chip Can Mimic Liver Tropism of Extracellular Vesicles Derived from Breast Cancer Cells.

Extracellular vesicles (EVs) from cancer cells remodel distant organs to promote metastasis in vivo. A biomimetic microsystem may compensate costly and time-consuming animal models to accelerate the study of EV organotropism. A tissue-based liver-kidney-on-a-chip is developed with precision-cut tissue slices (PTSs) cultured to represent individual organs.

The importance of spatial heterogeneity and self-restraint on mutualism stability - a quantitative review.

Understanding the factors that enable mutualisms to evolve and to subsequently remain stable over time, is essential to fully understand patterns of global biodiversity and for evidence based conservation policy. Theoretically, spatial heterogeneity of mutualists, through increased likelihood of fidelity between cooperative partners in structured populations, and 'self-restraint' of symbionts, due to selection against high levels of virulence leading to short-term host overexploitation, will result in either a positive correlation between the reproductive success of both mutualists prior to the total exploitation of any host resource or no correlation after any host resource has been fully exploited. A quantitative review by meta-analysis on the results of 96 studies from 35 papers, showed no evidence of a significant fitness correlation between mutualists across a range of systems that captured much taxonomic diversity.

Non-quantitative adjustment of offspring sex ratios in pollinating fig wasps.

Fig wasp is one of the most well known model systems in examining whether or not the parents could adjust their offspring sex ratio to maximize their gene frequency transmission in next generations. Our manipulative experiments showed that, in all of the five pollinator wasps of figs (Agaonidae) that have different averages of foundress numbers per syconium, almost the same proportions of male offspring are produced in the experiment that foundresses deposit one hour then are killed with ether (66.1%-70.

Evolutionary stability in the asymmetric volunteer's dilemma.

It is often assumed that in public goods games, contributors are either strong or weak players and each individual has an equal probability of exhibiting cooperation. It is difficult to explain why the public good is produced by strong individuals in some cooperation systems, and by weak individuals in others. Viewing the asymmetric volunteer's dilemma game as an evolutionary game, we find that whether the strong or the weak players produce the public good depends on the initial condition (i.