ABSTRACT
Owing to the outbreak of COVID-19, researchers are exploring methods to prevent contact and non-contact infections that occur via multiple transmission routes. However, studies on pre-venting infections caused by droplet transmission in public transportation are insufficient. To prevent the spread of infectious diseases, a new ventilation system in railway vehicles must be devel-oped. In this study, a novel vertical drop airflow (VDA) system is proposed to mitigate the effect of droplet transmission in a high-speed train cabin. The droplet transmission route and droplet fate are investigated using three-dimensional fluid dynamics simulations, performed employing the Eu-lerian–Lagrangian model. Additionally, a porous model is adopted to simulate the effect of close-fitting masks. The results indicate that 120 s after coughing, the decrease in the droplet number in the VDA system is 72.1% of that observed in the conventional system. Moreover, the VDA system effectively suppresses droplet transmission because the maximum droplet travel distances of the VDA systems are 49.9% to 67.0% of those of the conventional systems. Furthermore, the effect of reducing droplet transmission by wearing a close-fitting mask is confirmed in all systems. Thus, the decrease in both droplet number and droplet transmission area in train cabins validate that the proposed VDA system has an effective airflow design to prevent droplet infection. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
ABSTRACT
In the wake of the SARS-CoV-2 pandemic, inactivating bioaerosols became a pivotal issue which helps to prevent the transmittance of SARS-CoV-2. Thus, the current study was conducted to investigate a potential inactivating method using both ozone (O-3) and ultraviolet C (UVC). Individual and integrated effects of O-3 and UVC were compared. A solution containing approximately 4 similar to 7.3 x 10(6) CFU/mL of Salmonella typhimurium bacteria was used to produce bacteria droplets. These droplets were exposed to O-3 and UVC to determine the reduction rate of bacteria. The exposure times were set as 1 and 30 minutes. Ozone concentrations were 100 and 200 ppmv. UVC-LEDs were used as a UVC source. Peak wavelength of the UVC-LED was 275 nm and the irradiation dose was 0.77 mW/cm(2). In terms of O-3 and UVC-LED interaction, 194 ppmv styrene was used as a target compound to be removed. Considering the O-3 and UVC-LED interaction, the presence of O-3 could reduce the performance of the UVC-LED, and UVC-LED could also reduce significant amount of O-3. The sequence of O-3 and UVC-LED treatment was as follows: O-3 was exposed at first, then UVC-LED, and this order showed the best reduction ratio ( > 99.9%). Therefore, if O-3 and UVC-LED is used to disinfect Salmonella typhimurium bacteria contained in droplets, bacteria should be separately exposed to O-3 and UVC-LED in order to improve the inactivation efficiency.
ABSTRACT
With the expansion of the COVID-19 vaccination drive, an increasing number of adverse effects are surfacing. A 74-year-old woman presented with multiple erythematous and itchy patches on several sites. She had no relevant medical history, apart from the first AZD1222 vaccination 1 month previously. Microscopically, epidermal changes, including mild spongiosis and parakeratosis, were observed. Tight perivascular lymphocytic infiltration (coat-sleeve pattern) was also observed in the dermis. The final diagnosis was erythema annulare centrifugum (EAC) induced by SARS-CoV-2 vaccination. Based on this report, dermatologists should be aware of the possibility of EAC from the AZD1222 vaccination.
Subject(s)
COVID-19 Vaccines/adverse effects , Erythema/chemically induced , Skin Diseases, Genetic/chemically induced , Aged , Female , HumansABSTRACT
Background and aim: Healthcare workers (HCW) are at increased risk of developing coronavirus disease 2019 (COVID-19). Providing cardiopulmonary resuscitation (CPR) to a COVID-19 patient is an aerosol-generating procedure. Guidelines for personal protective equipment (PPE) use and providing CPR to COVID-19 patients have been developed locally for the purpose of improving patient and HCW safety. Medical simulation is used to educate HCWs. We aimed to the determine the utility of COVID-19 CPR simulation in improving HCWs ability, confidence and knowledge in managing medical emergencies. Methods: 108 HCWs participated in a standardised 1-h moderate-fidelity CPR simulation designed and delivered in the medical simulation laboratory at our tertiary metropolitan hospital in Sydney, Australia. Participant-filled surveys were collected pre and post-simulation. Data was categorised into assessment of perceived knowledge, confidence and ability in PPE use and providing CPR using a 5-point Likert scale. Statistical analyses were performed using the Mann–Whitney U test. Results: Of 108 participants, 94 were doctors and 14 nurses. The mean subjective scores of confidence in providing CPR pre and post-simulation were 2.3 and 3.9 respectively (p < 0.001);perceived ability to provide CPR pre and post-simulation were 2.5 and 4.0 respectively (p < 0.001);confidence in PPE use pre and post-simulation were 3.1 and 4.2 respectively (p < 0.001);perceived ability in PPE use pre and post-simulation were 3.3 and 4.2 respectively (p < 0.001) (see Fig. 1). Adequate knowledge of specific elements of newly developed guidelines improved from 14% to 97% of participants pre and post-simulation. Conclusion: Our study shows that during the COVID-19 pandemic, simulation of medical emergency scenarios is a valuable tool in improving knowledge, confidence and perceived ability of HCWs in PPE use and providing CPR in medical emergencies where real-life experience may be limited. Inadequate preparation before encountering real-life scenarios in COVID-19 patients may compromise the safety of both patients and healthcare workers.