[Risk factors of asthma among children aged 0 - 14 in Suzhou city].

OBJECTIVE: This study aimed to investigate risk influencing factors of asthma for children in Suzhou City, China. METHODS: A survey of asthma was conducted on children aged 0 - 14 with or without asthma from September 2010 to April 2011 in Pingjiang district of Suzhou city. A total of 271 children diagnosed with asthma were considered as a case group, and 271 non-asthmatic children with the same age, sex and living region formed the control group. Risk factors were analyzed with χ(2) test and logistic regression analysis. RESULTS: All children were Han. The case group was composed of 165 boys and 106 girls, so was the case group. The average age was (7.5 ± 2.3) years for the case group and (7.8 ± 2.9) years for the control group, which did not showed any significant difference (P > 0.05). Family history of allergy (OR = 10.624, 95%CI: 6.294 - 18.623), history of children's eczema (OR = 4.403, 95%CI: 8.627 - 29.632), history of allergic rhinitis (OR = 6.871, 95%CI: 7.658 - 31.871), passive smoking when baby was born (OR = 3.323, 95%CI: 3.541 - 11.634), mold contamination (OR = 1.837, 95%CI: 1.531 - 4.926) were the risk factors, and breast-feeding (OR = 0.513, 95%CI: 0.418 - 0.914) was the protective factor. CONCLUSION: Family history of allergy, history of children's eczema, history of allergic rhinitis, passive smoking, and old contamination are the risk factors, and breast-feeding is the protective factor.

Performances of biological aerated filter employing hollow fiber membrane segments of surface-improved poly (sulfone) as biofilm carriers.

Using the surface of poly (sulfone) hollow fiber membrane segments as grafted layer, the hydrophilic acrylamide chain was grafted on by UV-photoinduced grafting polymerization. The gained improvement of surface wettability for the modified membrane was tested by measuring the contact-angle as well as FTIR spectra. Then correlation between the hydrophilic ability of support material and the biofilm adherence ability was demonstrated by comparing the pollutant removal rates from urban wastewater via two identical lab-scale up-flow biological aerated filters, one employed the surface wettability modified poly (sulfone) hollow fiber membrane segment as biofilm carrier and the other employed unmodified membrane segment as biofilm carrier. The experimental results showed that under the conditions of influent flux 5 L/h, hydraulic retention time 9 h and gas to liquid ratio (G/L) 10:1, the removal rates of chemical oxygen demand (COD) and ammonium nitrogen (NH4(+)-N) for the modified packing filter and the unmodified packing filter was averaged at 83.64% and 96.25%, respectively, with the former filter being 5%-20% more than the latter. The effluent concentration of COD, NH4(+)-N and turbidity for the modified packing filter was 25.25 mg/L, 2 mg/L and 8 NTU, respectively. Moreover, the ammonium nitrogen removal performance of the filter packing the modified PSF was compared with the other bioreactor packing of an efficient floating medium. The biomass test indicated that the modified membrane matrixes provided better specific adhesion (3310-5653 mg TSS/L support), which gave a mean of 1000 mg TSS/L more than the unmodified membrane did. In addition, the phenomenon of simultaneous denitrification on the inner surface of the support and nitrification on the outer surface was found in this work.

Gas-initiation under UV and liquid-grafting polymerization on the surface of polysulfone hollow fiber ultrafiltration membrane by dynamic method.

Using the inner-surface of polysulfone hollow fiber ultrafiltration membranes as grafted layer, the method of gas-initiation and liquid-polymerization has been studied, which aimed to adjust the diameter of the pores in the membranes. The degree of polymerization varied with the changes of the parameters, such as irradiation time, monomer concentration, temperature and time of polymerization and soon. The results indicated that using benzophenone (BP) which is in a gaseous condition as photo-initiator, acrylamide as graft monomer, the polyacrylamide chain was grafted on the surface of membranes. After the surface membrane being modified, the water flux and retention altered, and thus it can be seen that the diameter of the pores in the membrane was altered. These experiments contribute to finding a new way to produce the hollow fiber membrane with the small pore size and are extraordinarily worth developing and studying.