Track theory rested on the foundation of the radial distribution of dose from δ rays as the central contribution of atomic physics to heavy ion radiobiology.Here,a new calculation of the radial distribution of dose i...Track theory rested on the foundation of the radial distribution of dose from δ rays as the central contribution of atomic physics to heavy ion radiobiology.Here,a new calculation of the radial distribution of dose is applied, in which the classical angular distribution of dose of delta rays and a logarithmic polynomial representation of the electron range-energy relation are used,to form the basis of the present thindown calculation.Calculations of inactivation cross sections for heavy ions in the track width regime displaying thindown for E.Colt B/r and Bs-1,and for Bacillus Subtilus are straightforward for these are 1-hit detectors,Calculations for V-79 hamster cells are more complex.They follow the original development of this model for eucaryotic cells,and make use of the cross sections calculated for hypothetical internal targets which are then asserted to be proportional to the measured cellular inactivation cross sections.The results are in reasonable agreement with experimental data.展开更多
Objective： Chlorine dioxide （CD） gas has been used as a fumigant in the disinfection of biosafety labo- ratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on si...Objective： Chlorine dioxide （CD） gas has been used as a fumigant in the disinfection of biosafety labo- ratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six ma- terials [stainless steel （SS）, painted steel （PS）, polyvinyl chlorid （PVC）, polyurethane （PU）, glass （GS）, and cotton cloth （CC）] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy. Methods： Material coupons （1.2 cm diameter of SS, PS, and PU; 1.0 cmx1.0 cm for PVC, GS, and CC） were contaminated with 10 IJI of Bacillus subtilis var. niger（ATCC 9372） spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min. Results： The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% （volume ratio, v/v） for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials. Conclusions： The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.展开更多
文摘Track theory rested on the foundation of the radial distribution of dose from δ rays as the central contribution of atomic physics to heavy ion radiobiology.Here,a new calculation of the radial distribution of dose is applied, in which the classical angular distribution of dose of delta rays and a logarithmic polynomial representation of the electron range-energy relation are used,to form the basis of the present thindown calculation.Calculations of inactivation cross sections for heavy ions in the track width regime displaying thindown for E.Colt B/r and Bs-1,and for Bacillus Subtilus are straightforward for these are 1-hit detectors,Calculations for V-79 hamster cells are more complex.They follow the original development of this model for eucaryotic cells,and make use of the cross sections calculated for hypothetical internal targets which are then asserted to be proportional to the measured cellular inactivation cross sections.The results are in reasonable agreement with experimental data.
基金Project supported by the National Key Science and Technology Specific Project for Prevention and Treatment of Major Infectious Diseases in China (No. 2009ZX10004-709)the National Key Technology R&D Program in the 11th Five-Year Plan of China (No.2008BAI62B01)
文摘Objective： Chlorine dioxide （CD） gas has been used as a fumigant in the disinfection of biosafety labo- ratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six ma- terials [stainless steel （SS）, painted steel （PS）, polyvinyl chlorid （PVC）, polyurethane （PU）, glass （GS）, and cotton cloth （CC）] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy. Methods： Material coupons （1.2 cm diameter of SS, PS, and PU; 1.0 cmx1.0 cm for PVC, GS, and CC） were contaminated with 10 IJI of Bacillus subtilis var. niger（ATCC 9372） spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min. Results： The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% （volume ratio, v/v） for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials. Conclusions： The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.
