The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in water and wastewater has recently been reported. According to the updated literature, the stools and masks of the patients diagnosed with coronavirus disease (COVID-19) were considered as the primary route of coronavirus transmission into water and wastewater. Most of coronavirus types which attract human (possible for SARS-CoV-2) are often inactivated rapidly in water (i.e., the survival of human coronavirus 229E in water being seven days at 23 °C). However, the survival period of coronavirus in water and wastewater strongly depends on temperature, kinds of wastewater, concentration of suspended solids and organic matter, solution pH, and the dose of disinfectant used. The World Health Organization has claimed that the current disinfection process of drinking water could effectively inactivate most of the bacterial and viral communities present in water, especially SARS-CoV-2 (more sensitive to disinfectant like free chlorine). A recent study confirmed that SARS-CoV-2 RNA was detected in inflow wastewater (but not detected in outflow one). Although the existence of SARS-CoV-2 in the water influent has been confirmed, an important question is whether it can survive or infect after the disinfection process of drinking water. To date, there is one study confirming that the infectivity of SARS-CoV-2 in water for people was null based on the absence of cytopathic effect (CPE) in infectivity tests. Therefore, further studies should focus on the survival of SARS-CoV-2 in water and wastewater under different operational conditions (i.e., temperature and water matrix) and whether the transmission from COVID-19-contaminated water to human is an emerging concern. Although paper-based devices have been suggested for detecting traces of SARS-CoV-2 in water, the protocols and appropriate devices should be developed soon. Wastewater and sewage workers should follow the procedures for safety precaution against SARS-CoV-2 exposure.

Background: Vaccination is one of the best ways to control a pandemic such as COVID-19. However, identifying community apprehensions towards vaccination needs to be understood in detail. This study aims to determine the factors that can predict the acceptance of the COVID-19 vaccine. Methods: A cross-sectional study was considered by systematic random sampling of 425 adults with chronic illnesses in Ho Chi Minh City. Data were collected between December 2020 and January 2021 via a self-administered, structured questionnaire. The main outcome was the acceptance of future COVID-19 vaccinations. Results: A total of 425 eligible adults responded to the survey, whose mean age was 52.9 ±15.6 years; 67.8% of them were women, more than a half of them had high school education level or higher (57.4%) and received COVID-19 information mainly via television and social media accounted for 82.4% and 58.1%, respectively. Overall, knowledge of COVID-19 was reported as relatively good, with a mean score of 7.11 ± 1.77 (0-9). Determinants of vaccination acceptance were knowledge and cues to action. Accordingly, there was a 1.2-fold increase in the odds of acceptance of COVID-19 vaccination for a 1-unit increase in "the total knowledge score" (AOR 1.2, 95% CI: 1.1-1.3, p<0.05), and there was a 3.2-fold increase in the odds of vaccination acceptance for a 1-unit increase in "cues to action" (AOR 3.2, 95% CI: 1.7-5.8, p<0.001). Conclusion:Determinants that influence the intention to have the COVID-19 vaccination are identified, which can be applied to future health education interventions that should focus on enhanced knowledge towards COVID-19 via mass media messages and cues to action from healthcare workers' recommendations to promote vaccine acceptance.

An attempt has been made in this review to provide some insights into the possible adsorption mechanisms of hexavalent chromium onto layered double hydroxides-based adsorbents by critically examining the past and present literature. Layered double hydroxides (LDH) nanomaterials are typical dual-electronic adsorbents because they exhibit positively charged external surfaces and abundant interlayer anions. A high positive zeta potential value indicates that LDH has a high affinity to Cr(VI) anions in solution through electrostatic attraction. The host interlayer anions (i.e., Cl -, NO3 -, SO4 2-, and CO3 2-) provide a high anion exchange capacity (53-520 meq/100g) which is expected to have an excellent exchangeable capacity to Cr(VI) oxyanions in water. Regarding the adsorptioncoupled reduction mechanism, when Cr(VI) anions make contact with the electron-donor groups in the LDH, they are partly reduced to Cr(III) cations. The reduced Cr(III) cations are then adsorbed by LDH via numerous interactions, such as isomorphic substitution and complexation. Nonetheless, the adsorption-coupled reduction mechanism is greatly dependent on: (1) the nature of divalent and trivalent salts utilized in LDH preparation, and (2) the types of interlayer anions (i.e., guest intercalated organic anions). The low Brunauer-Emmett-Teller specific surface area of LDH (1.80-179 m 2 /g) suggests that pore filling played an insignificant role in Cr(VI) adsorption. The Langmuir maximum adsorption capacity of LDH (Q o max) toward Cr(VI) was significantly affected by the used inorganic salt natures and synthetic methods of LDH. The Q o max values range from 16.3 mg/g to 726 mg/g. Almost all adsorption processes of Cr(VI) by LDH-based adsorbent occur spontaneously (∆G° <0) and endothermically (∆H° >0) and increase the randomness (∆S° >0) in the system. Thus LDH has much potential as a material that can effectively remove anion pollutants, especially Cr(VI) anions in industrial wastewater.

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BackgroundMinimally invasive mitral valve surgery is becoming a gold standard and provides many advantages for patients. A learning curve is required for a surgeon to become proficient, and the exact number to overcome this curve is controversial. Our study aimed to define this number for mitral valve surgery in general, for replacement and repair separately.MethodsA total of 204 mitral valve surgeries were performed via the right minithoracotomy approach from October 2014 to January 2019 by a single surgeon who isexperienced in conventional mitral valve surgery. Learning curves were analysed based on the trend of important variables (cross-clamp time, CPB time, ventilation time, ICU time, composite technical failure) over time, and the number of operations required was calculated by CUSUM method.ResultsMIMVS provided an excellent outcome in the carefully selected patients, with low mortality of 0.5% and low rate of complications. The decreasing trend of the important variables were observed over the years and as the cumulative number of procedures increased. The number of operations required to overcome the learning curve was 75 to 100 cases. When considered separately, the quantity for mitral valve replacement was 60 cases, whereas valve repair necessitated at least 90 cases to have an acceptable technical complication rate.ConclusionMIMVS is an excellent choice for mitral valve surgery. However, this approach required a long learning curve for a surgeon who is experienced in conventional mitral valve surgery.Trial registrationThe research was registered and approved by the ethical board of the University of Medicine and Pharmacy at Ho Chi Minh City, number 141/DHYD-HDDD, on April 11th 2018.

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