ABSTRACT
The protection effects of wearing masks against viruses and bacteria have been verified many times over previous pandemics and infectious diseases. However, the supply of the surgical masks can barely meet the surging demand at the early stage (first 12 months) of the outbreak of a pandemic. Thus, it is essential to use surgical masks wisely in such urgent times. In this work, we selected two types of surgical masks and systematically explored how actual wearing time influences the protective performances of the masks. Each type of surgical masks was worn for 4, 10, 24, 32 and 48 h, respectively, and the results show that with the increase of actual wearing time, both particulate filtration efficiency (PFE) and bacterial filtration efficiency (BFE) of the masks decline. After wearing for 32 h, the PFEs of both types of masks were still far above the corresponding standard (>= 30%, according to YY0469-2011). After wearing for 10 h, the BFEs of both masks were over 95% (which is regarded as the safe value), whereas after 24 and 32 h of wearing, the BFE of one type of mask decreased obviously to 91.6% and 80.0%, respectively. Based on these results, it is rational to conclude that the wearing time of surgical masks should be no more than 10 h.
ABSTRACT
Objective: The observational study was intended to explore the weight changes and risk factors of weight gain during the self-quarantine and find available methods to lose weight. Method: This was an online retrospective observational study investigating the weight changes before and after home confinement. A total of 530 participants completed the online questionnaire. diet, sleep, self-reported depression, disease history and exercise information possibly relating to weight changes were incorporated into the questionnaire. The differences among four groups (underweight, normal weight, overweight and obesity) in BMI change and weight change were compared, and the risk factors of weight gain was also analyzed by multiple linear regression analysis. Result: Participants were mostly between 21-50 years old, getting an average weight change of 0.82±3.31kg, and an average BMI change of 0.35 [-0.37, 1.00]. 43.77% of them gained weight by 2.99±2.29kg averagely. People with normal weight were easier to gain weight than obese group (p=0.001). There were differences in food intake (p<0.001), eating habits(p<0.001), taste preference (p=0.047), daily exercise step change(p=0.007), exercise (p=0.02) between non-weight gain group and weight gain group. The multiple linear regression revealed that weight gains were associated with sex (p=0.002), food intake (p=0.004), current daily exercise step (p=0.009) and self-reported depression (p=0.002) and weight loss was related to food intake (p=0.004) and pre-BMI (p=0.001). Conclusion: Eating irregularly, increasing food intake, self-reported depression and decreased daily steps were risk factors of weight gain, yet weight loss was related to decreased food intake and pre-BMI.