Objective: To investigate damage effects of ultraviolet irradiation on eternal keratinocyte-HaCaT cells and to evaluate photo-protective efficiency of hydroxychloroqine and Traditional Chinese Medicines(epigallocatech...Objective: To investigate damage effects of ultraviolet irradiation on eternal keratinocyte-HaCaT cells and to evaluate photo-protective efficiency of hydroxychloroqine and Traditional Chinese Medicines(epigallocatechingallate[EGCG], baikal skullcap root and szechwan lovge rhizome) on HaCaT cells damaged by middle wave ultraviolet(UVB) irradiation. Methods: Subconfluent HaCaT cells were sham or UVB irradiated and treated with above TCM agents. The damage degree of HaCaT cells was observed by a light microscop. Cell growth was recorded by cell count and cellular activity was detected by MTT method. The secretion amount of IL-6 and TNF-α was measured by ELISA. Results: The irradiation damage of HaCaT cells was depended on the irradiated dosages and cellular activity was reduced by 36%-80%, with a maximum decrease over 90% after 72 h. The intervention of the above drugs may increase the cellular activity by 10%-72%. The photo-protective efficiency was more apparent in EGCG (from 1.19±0.07 to 1.28±0.06, P<0.01) than that in hydroxychloroqine (from 0.43±0.04 to 0.96±0.04, P<0.05). The other two tested drugs also showed photo-protective effect(from 0.44±0.07 to 1.21±0.02, P<0.05). As to cytokine secretion, EGCG could decline the secretion amount of IL-6 and TNF-α apparently. Hydroxychloroqine and baikal skullcap root baikal skullcap root could only reduce the secretion of IL-6. The secretion of IL-6 and TNF-α could not be inhibited by szechwan lovge rhizome. Conclusion: The injury effect of UVB irradiation on cultured keratinocytes is dose-dependent and the tested drugs have photo-protective potency. Inhibition of cytokine secretion may be one of the mechanisms related to reducing the damage effect of UVB irradiation.展开更多
Flying condition with angle of attack is inevitable in a hypersonic vehicle,and it may influence the thermal protection system(TPS)performance of opposing jet and its combinations.A 3D Navier–Stokes equation and shea...Flying condition with angle of attack is inevitable in a hypersonic vehicle,and it may influence the thermal protection system(TPS)performance of opposing jet and its combinations.A 3D Navier–Stokes equation and shear stress transfer(SST)k-ωmodel with compressible correction are employed to simulate the angle of attack characteristics of a blunt body with opposing jet and platelet transpiration TPS.The flowfield and heat flux transfer for angles of attack 0°,3°,6°with jet pressure ratio PR=0.1 and 0°,6°,12°with PR=0.2 are obtained.Numerical results show that the flowfield is no longer symmetrical with the effect of the angle of attack.The flowfield and heat transfer in windward and leeward performed adversely.The recompression shock wave in windward is strengthened,which increases local temperature and strengthens heat transfer.The opposing jet fails in thermal protection when the angle of attack reaches critical value;however,the critical angle of attack can be promoted by increasing PR.Finally,the transpiration gas can strengthen the cooling efficiency of windward,thereby,increasing the critical angle of attack.展开更多
文摘Objective: To investigate damage effects of ultraviolet irradiation on eternal keratinocyte-HaCaT cells and to evaluate photo-protective efficiency of hydroxychloroqine and Traditional Chinese Medicines(epigallocatechingallate[EGCG], baikal skullcap root and szechwan lovge rhizome) on HaCaT cells damaged by middle wave ultraviolet(UVB) irradiation. Methods: Subconfluent HaCaT cells were sham or UVB irradiated and treated with above TCM agents. The damage degree of HaCaT cells was observed by a light microscop. Cell growth was recorded by cell count and cellular activity was detected by MTT method. The secretion amount of IL-6 and TNF-α was measured by ELISA. Results: The irradiation damage of HaCaT cells was depended on the irradiated dosages and cellular activity was reduced by 36%-80%, with a maximum decrease over 90% after 72 h. The intervention of the above drugs may increase the cellular activity by 10%-72%. The photo-protective efficiency was more apparent in EGCG (from 1.19±0.07 to 1.28±0.06, P<0.01) than that in hydroxychloroqine (from 0.43±0.04 to 0.96±0.04, P<0.05). The other two tested drugs also showed photo-protective effect(from 0.44±0.07 to 1.21±0.02, P<0.05). As to cytokine secretion, EGCG could decline the secretion amount of IL-6 and TNF-α apparently. Hydroxychloroqine and baikal skullcap root baikal skullcap root could only reduce the secretion of IL-6. The secretion of IL-6 and TNF-α could not be inhibited by szechwan lovge rhizome. Conclusion: The injury effect of UVB irradiation on cultured keratinocytes is dose-dependent and the tested drugs have photo-protective potency. Inhibition of cytokine secretion may be one of the mechanisms related to reducing the damage effect of UVB irradiation.
文摘Flying condition with angle of attack is inevitable in a hypersonic vehicle,and it may influence the thermal protection system(TPS)performance of opposing jet and its combinations.A 3D Navier–Stokes equation and shear stress transfer(SST)k-ωmodel with compressible correction are employed to simulate the angle of attack characteristics of a blunt body with opposing jet and platelet transpiration TPS.The flowfield and heat flux transfer for angles of attack 0°,3°,6°with jet pressure ratio PR=0.1 and 0°,6°,12°with PR=0.2 are obtained.Numerical results show that the flowfield is no longer symmetrical with the effect of the angle of attack.The flowfield and heat transfer in windward and leeward performed adversely.The recompression shock wave in windward is strengthened,which increases local temperature and strengthens heat transfer.The opposing jet fails in thermal protection when the angle of attack reaches critical value;however,the critical angle of attack can be promoted by increasing PR.Finally,the transpiration gas can strengthen the cooling efficiency of windward,thereby,increasing the critical angle of attack.
