RESUMO
Objectives: To explore the association between outdoor physical activities and PM2.5in Chinese adults. Methods: Data from present study were derived from the prospective urban and rural epidemiology study in China (PURE-China), outdoor physical activities were obtained by using structured and standardized questionnaire, and PM2.5and NO2values were simulated via the longitudes and latitudes of enrolled communities from NASA satellites. Finally, data form 34 064 residents were analyzed. Residents were divided into low physical activity group (<1 386 METs-min/week, n=16 369) and high physical activity group (≥1 386 METs-min/week, n=17 695). Linear correlation and binary logistic regression were used to evaluate the association between outdoor physical activities and PM2.5. Results: Of the 34 064 people included in the study, men and women accounted for 43.6% and 56.4% respectively, the average annual PM2.5concentration was 67.8 μg/m3. PM2.5was associated with high adult outdoor physical activity (OR<1), and with the increase of PM2.5cocentration, the relationship of outdoor physical activity is negative (trend test P<0.05). There was a certain association between PM2.5and high outdoor physical activity among different age groups and gender groups. Conclusions: There is a negative correlation between PM2.5and outdoor physical activity. The possibility of high outdoor physical activity decreases in proportion to the increase of PM2.5concentration. Our results suggest that people actively change their physical activity under the condition of air pollution.
RESUMO
In this study, we used Shirasu porous glass membrane (SPG) as a template and hydroxy camptothecin (HCPT) as a model drug to prepare the comet-shaped MePEG[methoxyl poly(ethylene glycol)]-PLGA[poly(lactic-co-glycolic acid)-HCPT amphiphilic block copolymer. Our method was optimized by the orthogonal design method. The partical size, zeta potential, drug-loaded content, yield, shape and status of the obtained comet-shaped MePEG-PLGA-HCPT particles were further characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM)/transmission electron microscopy (TEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) et al, respectively. In vitro release was preliminary evaluated. MTT assay to preliminary evaluate the cytotoxicity of particles against human liver BEL-7402 cells. Based on these experimental results, the optimal preparation conditions contain:weight ratio of HCPT to MePEG-PLGA was 1:1, nitrogen pressure was 100 kPa and SPG membrane pore size was 1.1 μm. The particles exhibited a comet-shaped shape, fairly uniform size and were well dispersed. The drug-loading content was 46.2%, with yield of 96.4%, and zeta -31.4 mV. The distribution of HCPT in particles was very uniform, and HCPT showed a amorphous state existed in particles. The release behavior in vitro showed sustained releasing,and with the drug loading content in proportion to the release of the drug. MTT test indicated that the HCPT-loaded comet-shaped particles had enhanced the cytotoxicity against human liver BEL-7402 cells relatively to the HCPT-loaded spherical particles in vitro. The results showed a promising potential application of the preparation in clinical treatment of tumor.