Vu Thi Thu Trang

The coronavirus disease 2019 (COVID-19) pandemic has caused a lot of ethical controversy in the equal provision of healthcare, including vaccination. Therefore, our study was designed to assess the impact of Ho Chi Minh City’s policy to hold the second dose of the COVID-19 vaccine. Using a cross-sectional study design to assess low saturation of peripheral oxygen (SPO2) risk based on vaccination status, we included patients who were confirmed to have SARS-CoV-2 and were treated at home. The stepwise method was used to determine participants’ low SPO2 risk-related factors. The average age of the 2836 respondents was 46.43 ± 17.33 (years). Research results have shown that seven factors are related to the low SPO2 status of participants, including age, sneezing, shortness of breath, coughing, and fainting as COVID-19 symptoms, the number of people living with COVID-19, and a history of lung disease. A statistically significant (p = 0.032) finding in this study was that fully vaccinated patients had a 6% lower risk of low SPO2 compared to the first dose less than 21 days group. This result was similar in the vaccine holder group (p < 0.001). Holding the second dose of the COVID-19 vaccine is associated with a lower SPO2 risk than that of fully vaccinated patients. Therefore, this approach should be considered by governments as it could bring a greater benefit to the community.

In this paper, a new reducing agent known as ferro-silicocalcium is being studied for its application in magnesium production through the Pidgeon process. Ferro-silicocalcium with main phase components CaSi2 and Si can reduce Mg from dolomite at a lower temperature than a traditional reducing agent. It thus improves the efficiency of magnesium production and solves the large energy consumption problem of the Pidgeon process. This paper presents thermodynamics calculations and experimental study on reducing magnesium from Thanhhoa dolomite with the new reducing agents known as ferro-silicocalcium and ferrosilicon as traditional reducing agents. From the thermodynamics calculations, CaSi2 in the ferro-silicocalcium can eliminate magnesium oxide at temperatures 1000°C lower than FeSi2 in ferrosilicon. This leads to a substantial decrease in the recovery temperature. When CaSi2 is decomposed, it releases silicon to improve the reduction process at temperatures greater than 1100°C. Experiments are performed to confirm the calculation results. The reduction process of dolomite by ferro-silicocalcium and ferrosilicon was analyzed by phases analysis of reduction slag through X-ray diffraction. The experimental results show that when using ferro-silicocalcium as a reducing agent, the recovering magnesium oxide efficiency reaches 91.3% over three hours with a recovering temperature of 1200°C. The efficiency is 7% higher than the traditional method using ferrosilicon under the same conditions. This proves that using ferro-silicocalcium as a reducing agent reduces the operating temperature of the reducing system and saves energy for the whole process. Therefore, ferro-silicocalium promises to be an effective alternative reducing agent in magnesium production.

Aims: Understanding of the perceived stress and coping strategies adopted by people is important for contemplating the consequences of a pandemic on mental health of people globally. In this study, we intended to assess the perceived stress status under quarantine/isolation globally during the COVID-19 pandemic.Methods: This is a multicentre, multinational cross-sectional study that recruited isolated/quarantined individuals suspected or confirmed to have COVID-19 to assess the psychological impact of the quarantine/isolation experience by answering a survey distributed online.Results: The study was conducted across 63 participating countries, gaining 1,871 valid responses. There was a higher proportion of female participants in the Moderate to High Perceived Stress Scores (MH-PSS) group compared to the Low Perceived Stress Score group (66.0 vs. 52.0%) and a higher proportion of individuals whose marital status was single had MH-PSS (57.1%). Also, individual's religion (Christian, Hindu, and Muslim), no formal education level, being exposed to a confirmed or suspected COVID-19 patient, being forced to be quarantined/isolated, uncomfortable feeling during quarantine period may significantly increase the risk of MH-PSS (p < 0.05).Conclusions: Many factors can predict stress in COVID-19 pandemic including female sex, being single, religion, no formal education, involuntary quarantine, location and reason of quarantine/isolation, and place of exposure.