The conventional silk fibroin(SF)films obtained by casting from SF aqueous solution are amorphous,and easily dissolved in water.This defect limits the practical use of SF films in biomedical field.A new water-insolubl...The conventional silk fibroin(SF)films obtained by casting from SF aqueous solution are amorphous,and easily dissolved in water.This defect limits the practical use of SF films in biomedical field.A new water-insoluble silk fibroin film(an SF-FA film)could be simply prepared by casting from SF formic acid solution.The physical properties and moisture permeability of SF-FA films were examined.The results show that the SF-FA film swollen in water exhibits outstanding pliability.The weight loss of SF-FA films in water is also very little.The unique physical properties for the SF-FA film in the wet relate to the intrinsic structure of the fibroin film.The cell viability of rat embryo dermal fibroblasts seeded on the control films and the SF-FA films was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.Results show that the optical density(OD)value of the SF-FA film is almost the same as that of the conventional SF film treated with alcohol,therefore,the SF-FA film has good cell compatibility.In addition,the SF-FA film is also a biodegradable material.Because of their good transparency,it is helpful in study of clinical experiment with the SF-FA films.展开更多
Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon （WIRC） component of total suspended particulates （TSP）, collected weekly during 2003, as well as from Oc...Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon （WIRC） component of total suspended particulates （TSP）, collected weekly during 2003, as well as from October 2005 to May 2006 at the WMO-GAW Mt. Waliguan （WLG） site. The overall average WlRC mass concentration was （1183 ± 120）ng/m3 （n = 79）, while seasonal averages were 2081 ± 1707 （spring）, 454±205 （summer）, 650 ±411 （autumn）, and 1019 ± 703 （winter） ng/m3. Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer, although WIRC concentrations were typically higher, especially in winter and spring. The δ13C PDB value （-25.3 ± 0.8）%0 determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion. No seasonal change in δ13C PDB was evident. The average percent Modern Carbon （pMC） for 14C in WIRC for winter and spring was （67.2 ± 7.7）% （n = 29）. Lower pMC values were associated with air masses trans- ported from the area east of WLG, while higher pMC values were associated with air masses from the Tibetan Plateau, southwest of WLG. Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.展开更多
基金National Programon Key Basic Research Project of China(973program)(No.2005CB623906)
文摘The conventional silk fibroin(SF)films obtained by casting from SF aqueous solution are amorphous,and easily dissolved in water.This defect limits the practical use of SF films in biomedical field.A new water-insoluble silk fibroin film(an SF-FA film)could be simply prepared by casting from SF formic acid solution.The physical properties and moisture permeability of SF-FA films were examined.The results show that the SF-FA film swollen in water exhibits outstanding pliability.The weight loss of SF-FA films in water is also very little.The unique physical properties for the SF-FA film in the wet relate to the intrinsic structure of the fibroin film.The cell viability of rat embryo dermal fibroblasts seeded on the control films and the SF-FA films was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.Results show that the optical density(OD)value of the SF-FA film is almost the same as that of the conventional SF film treated with alcohol,therefore,the SF-FA film has good cell compatibility.In addition,the SF-FA film is also a biodegradable material.Because of their good transparency,it is helpful in study of clinical experiment with the SF-FA films.
基金supported by the National Natural Sciences Foundation of China(Grant Nos.411751154083010240575013 and 40175032)
文摘Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon （WIRC） component of total suspended particulates （TSP）, collected weekly during 2003, as well as from October 2005 to May 2006 at the WMO-GAW Mt. Waliguan （WLG） site. The overall average WlRC mass concentration was （1183 ± 120）ng/m3 （n = 79）, while seasonal averages were 2081 ± 1707 （spring）, 454±205 （summer）, 650 ±411 （autumn）, and 1019 ± 703 （winter） ng/m3. Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer, although WIRC concentrations were typically higher, especially in winter and spring. The δ13C PDB value （-25.3 ± 0.8）%0 determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion. No seasonal change in δ13C PDB was evident. The average percent Modern Carbon （pMC） for 14C in WIRC for winter and spring was （67.2 ± 7.7）% （n = 29）. Lower pMC values were associated with air masses trans- ported from the area east of WLG, while higher pMC values were associated with air masses from the Tibetan Plateau, southwest of WLG. Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.
