Numerical Analysis on the Applicability of Air Purifier for Removal of Indoor Viral Contaminants

Many recent studies have been reported that the novel coronavirus (SARS-CoV-2) can spread through an airborne transmission route. Although ventilation is generally adopted to control viral infection through airborne transmission, a high ventilation rate will increase the energy consumption of air conditioning. Under such condition, the portable HEPA-filter air purifier might be an effective supplementary measure. However, past discussions on its efficacy in reducing indoor infection risks are limited. Therefore, this study aims to conduct a systematic investigation on the applicability of air purifier using Computational Fluid Dynamics (CFD) simulation. Two scenarios both with an air change rate of 0.5 1/h were considered. In Scenario a, a general room with size being 4 m x 5 m x 2.5 m (13.1 ft x 16.4 ft x 8.2 ft) was adopted. Viral contaminants were set as homogeneous emission. In Scenario b, a 6-mat bedroom with size being 2.7 m x 3.6 m x 2.5 m (8.9 ft x 11.8 ft x 8.2 ft) was adopted. Viral contaminants were assumed to be generated from a lying infector at 27 quanta/h constantly. The purifier was operated at a flow rate of 90 m(3)/h (3178 ft(3)/h). The results showed that a general household HEPA-filter air purifier has high effectiveness in removing indoor viral contaminants and infection risks. In Scenario b, to reach an infection probability of 0.2, it took a susceptible person only about 10 min of exposure time without purifier, but up to 50 min with a purifier. A larger flow rate can contribute to higher purifying effectiveness and a more thorough air mixing indoor. Moreover, the purifying effectiveness, distribution of contaminant concentration and infection probability were found to be influenced by the relative positions of the purifier inlet and outlet, ventilation air supply and exhaust, virus generation source, and indoor obstacles.

A comprehensive review and clinical guide to molecular and serological diagnostic tests and future development: In vitro diagnostic testing for COVID-19

COVID-19 is a contagious syndrome caused by SARS Coronavirus 2 (SARS-CoV-2) that requires rapid diagnostic testing to identify and manage in the affected persons, characterize epidemiology, and promptly make public health decisions and manage the virus present in the affected person and promptly make public health decisions by characterizing the epidemiology. Technical problems, especially contamination occurring during manual real-time polymerase chain reaction (RT-PCR), can result in false-positive NAAT results. In some cases, RNA detection technology and antigen testing are alternatives to RT-PCR. Sequencing is vital for tracking the SARS-CoV-2 genome's evolution, while antibody testing is beneficial for epidemiology. SARS-CoV-2 testing can be made safer, faster, and easier without losing accuracy. Continued technological advancements, including smartphone integration, will help in the current epidemic and prepare for the next. Nanotechnology-enabled progress in the health sector has aided disease and pandemic management at an early stage. These nanotechnology-based analytical tools can be used to quickly diagnose COVID-19. The SPOT system is used to diagnose the coronavirus quickly, sensibly, accurately, and with portability. The SPOT assay consists of RT-LAMP, followed by pfAgo-based target sequence detection. In addition, SPOT system was used to detect both positive and negative SARS-CoV-2 samples. This combination of speed, precision, sensitivity, and mobility will allow for cost-effective and high-volume COVID-19 testing. © 2023 the author(s), published by De Gruyter.

Insights into the performance and kinetics of face mask-derived nitrogen-doped porous carbon as peroxymonosulfate activator for gatifloxacin removal

The outbreak of COVID-19 has led to the increase in face mask waste globally. In this study, face mask-derived carbocatalysts doped with nitrogen (N-Mask) were fabricated through one-step pyrolysis of 1:5 w/w mixture of face mask and urea at different temperatures to activate peroxymonosulfate (PMS) for gatifloxacin (GAT) degradation. The N-Mask prepared at 800 degrees C (N-Mask800) exhibited the highest GAT degradation rate with k(app) = 0.093 min(-1) which could be attributed to its high N doping level (17.1 wt%) and highest specific surface area (237.13 m(2) g(-1)). The relationship between k(app), catalyst loading and PMS dosage at various pHs on GAT degradation were successfully established. It was also found that the GAT degradation rate was inhibited in the sequential operating mode compared to the simultaneous operating mode. It was construed that adsorption and catalysis share the same active sites. Deterioration in catalytic performance was observed over successive cycles due to the surface chemistry change during catalysis, and difficulty in catalyst recovery after treatment. Radical scavenger study revealed that both radical and nonradical pathways were involved during GAT degradation, with nonradical pathway playing a dominant role. XPS analysis revealed that pyrrolic N and graphitic N can facilitate PMS activation via radical and nonradical pathways. Based on the LC-MS/MS analysis, the GAT degradation intermediates were identified, and the possible degradation pathways were tentatively proposed. Overall, this study demonstrated that carbocatalyst derived from face mask could be transformed into costeffective and environmentally friendly PMS activator for environmental wastewater treatment applications.

Measurements of Exhaled Airflow Velocity Via Human Coughs Using Particle Image Velocimetry (PIV)

The sudden global outbreak of coronavirus diseases 2019 (COVID-19) has infected over seventy million people and resulted in over one million deaths by the end of 2020, posing a significant threat to human health. As potential carries of the novel coronavirus, exhaled airflow of infected individuals via coughs, are significant in virus transmission. This study measures human coughs' airflow velocity in a chamber filled with stage fog employing a particle image velocimetry (PIV) system. The purpose of this study is to examine and provide accurate boundary conditions for the prediction of the virus transmission routes using computational fluid dynamics (CFD) simulations. Sixty cough cases from ten healthy nonsmoking volunteers (five male and five female, averaged age of 29.3 +/- 4.0) are taken respectively, and ensemble-average operations are conducted to eliminate individual variations. Velocity distribution measurements are obtained in the vertical and horizontal planes around the mouth area. Temporal and spatial cough flow ensemble-averaged velocity profiles and standard deviations, cough duration time (CDT), peak velocity time (PVT), maximum cough velocities, and average spread angle of the cough jet are measured. Results show that the CDT of the cough airflow is 520-560 ms, and PVT is 20 ms. The male/ female averaged maximum velocity is 15.2/13.1 m/s, respectively. The average vertical/horizontal spread angle from the mouth is 15.3 degrees/13.3 degrees for males and 15.6 degrees/14.2 degrees for females, respectively. With the measurement data, it is possible to refine the initial boundary conditions of a simulated cough and model cough flows more accurately.

Psychological distress among infectious disease physicians during the response to the COVID-19 outbreak in the republic of korea

Background: This study aimed to investigate psychological distress among infectious disease (ID) physicians during the coronavirus disease (COVID-19) outbreak in the Republic of Korea. Methods: Using an online-based survey link sent via text message and email, we conducted a survey from April 21 to 25, 2020, targeting all ID physicians currently working in ID (n = 265). The questionnaire was based on the Maslach Burnout Inventory-Human Services Survey and the Depression, Anxiety, and Stress Scales, and information was collected on factors protecting against psychological distress and difficulties in relation to COVID-19. Results: Of 265 ID physicians, 115 (43.3%) responded, showing burnout (97, 90.4%), depression (20, 17.4%), anxiety (23, 20.0%), and stress (5, 4.3%). There were no differences in terms of distress between ID physicians who were directly involved in the care of patients with COVID-19 or not (Table 1). Greater than 50% of physicians valued their work and felt recognized by others, whereas < 10% indicated that sufficient human and financial support and private time had been provided during the outbreak. The most challenging issues concerned a lack of human resources for COVID-19 treatment or infection control, a shortage of personal protective equipment or airborne infection isolation rooms, pressure for research, and lack of guidelines for COVID-19 management (Figure 1). Conclusion: During the COVID-19 outbreak in the ROK, most respondents reported psychological distress. Preparing strategies for infectious disease outbreaks that support ID physicians is essential. (Figure Presented).

Clinical predictors of donor antibody titre and correlation with recipient antibody response in a COVID-19 convalescent plasma clinical trial.

BACKGROUND: Convalescent plasma therapy for COVID-19 relies on transfer of anti-viral antibody from donors to recipients via plasma transfusion. The relationship between clinical characteristics and antibody response to COVID-19 is not well defined. We investigated predictors of convalescent antibody production and quantified recipient antibody response in a convalescent plasma therapy clinical trial. METHODS: Multivariable analysis of clinical and serological parameters in 103 confirmed COVID-19 convalescent plasma donors 28 days or more following symptom resolution was performed. Mixed-effects regression models with piecewise linear trends were used to characterize serial antibody responses in 10 convalescent plasma recipients with severe COVID-19. RESULTS: Donor antibody titres ranged from 0 to 1 : 3892 (anti-receptor binding domain (RBD)) and 0 to 1 : 3289 (anti-spike). Higher anti-RBD and anti-spike titres were associated with increased age, hospitalization for COVID-19, fever and absence of myalgia (all P < 0.05). Fatigue was significantly associated with anti-RBD (P = 0.03). In pairwise comparison amongst ABO blood types, AB donors had higher anti-RBD and anti-spike than O donors (P < 0.05). No toxicity was associated with plasma transfusion. Non-ECMO recipient anti-RBD antibody titre increased on average 31% per day during the first three days post-transfusion (P = 0.01) and anti-spike antibody titre by 40.3% (P = 0.02). CONCLUSION: Advanced age, fever, absence of myalgia, fatigue, blood type and hospitalization were associated with higher convalescent antibody titre to COVID-19. Despite variability in donor titre, 80% of convalescent plasma recipients showed significant increase in antibody levels post-transfusion. A more complete understanding of the dose-response effect of plasma transfusion amongst COVID-19-infected patients is needed.

Clinical Presentation and Outcomes of Middle East Respiratory Syndrome in the Republic of Korea

Background: From May to July 2015, the Republic of Korea experienced the largest outbreak of Middle East respiratory syndrome (MERS) outside the Arabian Peninsula. A total of 186 patients, including 36 deaths, had been diagnosed with MERS-coronavirus (MERS-CoV) infection as of September 30th, 2015. Materials and Methods: We obtained information of patients who were confirmed to have MERS-CoV infection. MERS-CoV infection was diagnosed using real-time reverse-transcriptase polymerase chain reaction assay. Results: The median age of the patients was 55 years (range, 16 to 86). A total of 55.4% of the patients had one or more coexisting medical conditions. The most common symptom was fever (95.2%). At admission, leukopenia (42.6%), thrombocytopenia (46.6%), and elevation of aspartate aminotransferase (42.7%) were observed. Pneumonia was detected in 68.3% of patients at admission and developed in 80.8% during the disease course. Antiviral agents were used for 74.7% of patients. Mechanical ventilation, extracorporeal membrane oxygenation, and convalescent serum were employed for 24.5%, 7.1%, and 3.8% of patients, respectively. Older age, presence of coexisting medical conditions including diabetes or chronic lung disease, presence of dyspnea, hypotension, and leukocytosis at admission, and the use of mechanical ventilation were revealed to be independent predictors of death. Conclusion: The clinical features of MERS-CoV infection in the Republic of Korea were similar to those of previous outbreaks in the Middle East. However, the overall mortality rate (20.4%) was lower than that in previous reports. Enhanced surveillance and active management of patients during the outbreak may have resulted in improved outcomes. FAU - Choi, Won Suk