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Summary: Background: Exposure to fine particulate matter (with an aerodynamic diameter ≤ 2·5 μm, PM2·5) air pollution has been associated with skin‐related diseases or disorders. Objectives: To evaluate the potential skin‐protective effects of fish‐oil supplementation against PM2·5 exposure. Materials and methods: This is an exploratory analysis based on a pilot randomized, double‐blind, placebo‐controlled trial among 65 healthy young adults between September 2017 and January 2018 in Shanghai, China. We randomly assigned participants to take either fish oil or placebo 2·5 g daily for four consecutive months. Four rounds of skin D‐Squame® tape samples were collected in the last 2 months, and five secondary biomarkers of skin inflammation and oxidative stress were measured. Fixed‐site PM2·5 concentrations on campus were measured in real time. We used linear mixed‐effect models to analyse the associations between short‐term PM2·5 exposure and biomarkers in each group. Results: The 24‐h average PM2·5 concentration was 34·68 ± 15·83 μg m−3. There were generally weaker associations between PM2·5 and biomarkers in the fish‐oil group than in the placebo group, but the associations and the between‐group differences varied by biomarkers and lag periods. Compared with the placebo group, for a 10‐μg m−3 increase in PM2·5 concentration, the increments of interleukin‐1α and carbonyl protein in the fish‐oil group were 41·55% smaller [95% confidence interval (CI) 4·61–78·48%] at lag 0–48 h and 22·01% smaller (95% CI 11·25–32·77%) at lag 0–24 h, respectively. No significant between‐group differences were observed for other biomarkers. Conclusions: This study suggested that dietary fish‐oil supplementation may improve biomarkers of skin inflammation and oxidative‐stress response to short‐term PM2·5 exposure. What is already known about this topic? Fine particulate matter (with an aerodynamic diameter ≤2·5 μm, PM2·5) air pollution may contribute to a range of skin diseases, including inflammatory skin diseases.Few studies have evaluated the potential skin‐protective effects of dietary supplements of anti‐inflammatory and/or antioxidative agents against PM2·5 exposure.There is an urgent need for exploring a simple and effective way to protect skin health against exposure to ambient PM2·5 in areas with severe air pollution. What does this study add? Dietary fish‐oil supplementation may potentially improve biomarkers of skin inflammation and oxidative‐stress response induced by exposure to fine particulate pollution.Findings from this study, if confirmed and extended to vulnerable populations such as patients with existing skin disorders, may have significant clinical and public health implications. Plain language summary available online [ABSTRACT FROM AUTHOR]

Although administration of a second dose of varicella vaccine (2nd-dose VarV) to individuals who have previously received one-dose VarV has been recommended as a post-exposure prophylaxis (PEP) strategy for outbreak control, the effectiveness of this strategy remains unclear. We evaluated the vaccine effectiveness (VE) of 2nd-dose VarV as PEP among students involved in 129 varicella outbreaks in Shanghai, China from 2013 to 2016. Students who had received one-dose VarV more than 5 years prior to varicella exposure were eligible to receive 2nd-dose VarV as PEP. We evaluated the VE using the following formula: VE = (1 – hazard ratio (HR)) × 100%. A total of 6762 students were eligible for 2nd-dose VarV, of whom 58.6% accepted PEP after varicella exposure. The adjusted VE of 2nd-dose VarV as PEP was 77% (95% confidence interval 64–85%). In addition, the adjusted VE of 2nd-dose VarV as PEP in affected classrooms with high vaccine uptake was higher than that in classrooms with lower vaccine uptake (87% vs. 69%). The adjusted VE was also higher in students who received 2nd-dose VarV within 3 days of exposure than those who received it more than 3 days post exposure (77% vs. 64%). These Results suggest that administration of 2nd-dose VarV as PEP is an appropriate intervention for outbreak control in countries where two-dose VarV has not been adopted. [ABSTRACT FROM AUTHOR]

Understanding of gas migration behavior in saturated soft soil is of great importance for designing and construction activities involving applications of pneumatic caisson method and compressed-air tunneling technique in soft ground. For further investigation of mechanical effect on gas migration behavior in such applications, including gas flow rate, gas permeability, as well as the gas breakthrough pressure, step-wisely gas injection tests were conducted on Shanghai soft clay under different vertical loads in this paper. Results show that gas flow rate will increase as the injection pressure increases. The conventional two-phase flow theory, which is mainly governed by capillary pressure, can be used to model gas flow under lower gas injection pressures, but fails to describe gas flow under higher gas injection pressures, due to the significant influence of mechanical stress. As effective stress increases, gas permeability decreases sharply at the initial stage followed by a gradually stabilization stage due to the dissipation of mechanical effect. The mechanical stress has significant influence on gas permeability for specimens with higher compressibilities. Formation of gas flow pathways, either caused by capillary pressure or mechanical stress, can result in gas breakthrough, the corresponding pressure of which is determined according to the evolution of gas flow rate and can be used as the working gas pressure for avoiding significant gas loss in the gas-tight working structures in pneumatic caisson method and compressed air tunneling technique. Gas breakthrough pressure increases with the increase of vertical load. [ABSTRACT FROM AUTHOR]