In order to maximize the lethality and reversibility of the non-lethal laser weapons(NLLW) at the same time and thus provide a theoretical basis for the R&D of laser weapons in the future,this paper accurately ana...In order to maximize the lethality and reversibility of the non-lethal laser weapons(NLLW) at the same time and thus provide a theoretical basis for the R&D of laser weapons in the future,this paper accurately analyzed the limiting biological dose of irreversible damage to human skin caused by the NLLW.Firstly,based on the burn theory in medicine and the actual tactical background,this paper redefines the evaluation criteria of the limiting laser dose of NLLW to the human body.Secondly,on the basis of anatomical knowledge,a 5-layer finite element model(FEM) of superficial skin is proposed,constructed and verified,which can accurately describe the limiting reversible damage.Based on the optimized Pennes bioheat transfer equation,the diffusion approximation theory,the modified Beer-Lambert law,the Arrhenius equation,and combined with dynamic thermophysical parameters,this paper highly restored the temperature distribution and accurately solved the necrotic tissue distribution inside the human skin irradiated by 1064 nm laser.Finally,it is concluded that the maximum human dose of the1064 nm NLLW is 8.93 J/cm^(2),8.29J/cm^(2),and 8.17 J/cm^(2) when the light spots are 5 mm,10 mm and15 mm,respectively,and the corresponding output power of the weapon is 46.74 W,173.72 W and384.77 W.Simultaneously,the temperature and damage distribution in the tissue at the time of ultimate damage are discussed from the axial and radial dimensions,respectively.The conclusions and analysis methods proposed in this paper are of great guiding significance for future research in military,medical and many other related fields.展开更多
Objective To estimate the biological exposure limit （BEL） using benchmark dose （BMD） based on two sets of data from occupational epidemiology. Methods Cadmium-exposed workers were selected from a cadmium smelting ...Objective To estimate the biological exposure limit （BEL） using benchmark dose （BMD） based on two sets of data from occupational epidemiology. Methods Cadmium-exposed workers were selected from a cadmium smelting factory and a zinc product factory. Doctors, nurses or shop assistants living in the same area served as a control group. Urinary cadmium （UCd） was used as an exposure biomarker and urinary D2-microgloburin （B2M）, N-acetyl-D-D-glucosaminidase （NAG） and albumin （ALB） as effect biomarkers. All urine parameters were adjusted by urinary creatinine. Software of BMDS （Version 1.3.2, EPA.U.S.A） was used to calculate BMD. Results The cut-off point （abnormal values） was determined based on the upper limit of 95% of effect biomarkers in control group. There was a significant dose response relationship between the effect biomarkers （urinary B2M, NAG9 and ALB） and exposure biomarker （UCd）. BEL value was 5 μg/g creatinine for UB2M as an effect biomarker, consistent with the recommendation of WHO. BEL could be estimated by using the method of BMD. BEL value was 3 μg/g creafinine for UNAG as an effect biomarker. The more sensitive the used biomarker is, the more occupational population will be protected. Conclusion BMD can be used in estimating the biological exposure limit （BEL）. UNAG is a sensitive biomarker for estimating BEL after cadmium exposure.展开更多
The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported. The distributions of beta dose were measured by an extra...The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported. The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin, cornea, sclera, anterior chamber and lens of eyeball.The ratios among superficial absorbed dose D (0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6 mm are also obtained with Cross's methods. They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.展开更多
Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A nove...Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A novel approach to develop scientifically defensible levels of safety concern is presented and an example to determine acute and chronic pesticide food safety standard （PFSS） levels for the fungicide captan on strawberries is provided. Using this approach, the chronic PFSS level for captan on strawberries was determined to be 2 000 mg kg-1 and the acute PFSS level was determined to be 250 mg kg-1. Both levels are far above the existing tolerance and MRLs that commonly range from 3 to 20 mg kg-~, and provide evidence that captan residues detected at levels greater than the tolerance or MRLs are not of acute or chronic health concern even though they represent violative residues. The benefits of developing the PFSS approach to serve as a companion to existing tolerances/MRLs include a greater understanding concerning the health significance, if any, from exposure to violative pesticide residues. In addition, the PFSS approach can be universally applied to all potential pesticide residues on all food commodities, can be modified by specific jurisdictions to take into account differences in food consumption practices, and can help prioritize food residue monitoring by identifying the pesticide/commodity combinations of the greatest potential food safety concern and guiding development of field level analytical methods to detect pesticide residues on prioritized pesticide/commodity combinations.展开更多
文摘In order to maximize the lethality and reversibility of the non-lethal laser weapons(NLLW) at the same time and thus provide a theoretical basis for the R&D of laser weapons in the future,this paper accurately analyzed the limiting biological dose of irreversible damage to human skin caused by the NLLW.Firstly,based on the burn theory in medicine and the actual tactical background,this paper redefines the evaluation criteria of the limiting laser dose of NLLW to the human body.Secondly,on the basis of anatomical knowledge,a 5-layer finite element model(FEM) of superficial skin is proposed,constructed and verified,which can accurately describe the limiting reversible damage.Based on the optimized Pennes bioheat transfer equation,the diffusion approximation theory,the modified Beer-Lambert law,the Arrhenius equation,and combined with dynamic thermophysical parameters,this paper highly restored the temperature distribution and accurately solved the necrotic tissue distribution inside the human skin irradiated by 1064 nm laser.Finally,it is concluded that the maximum human dose of the1064 nm NLLW is 8.93 J/cm^(2),8.29J/cm^(2),and 8.17 J/cm^(2) when the light spots are 5 mm,10 mm and15 mm,respectively,and the corresponding output power of the weapon is 46.74 W,173.72 W and384.77 W.Simultaneously,the temperature and damage distribution in the tissue at the time of ultimate damage are discussed from the axial and radial dimensions,respectively.The conclusions and analysis methods proposed in this paper are of great guiding significance for future research in military,medical and many other related fields.
文摘Objective To estimate the biological exposure limit （BEL） using benchmark dose （BMD） based on two sets of data from occupational epidemiology. Methods Cadmium-exposed workers were selected from a cadmium smelting factory and a zinc product factory. Doctors, nurses or shop assistants living in the same area served as a control group. Urinary cadmium （UCd） was used as an exposure biomarker and urinary D2-microgloburin （B2M）, N-acetyl-D-D-glucosaminidase （NAG） and albumin （ALB） as effect biomarkers. All urine parameters were adjusted by urinary creatinine. Software of BMDS （Version 1.3.2, EPA.U.S.A） was used to calculate BMD. Results The cut-off point （abnormal values） was determined based on the upper limit of 95% of effect biomarkers in control group. There was a significant dose response relationship between the effect biomarkers （urinary B2M, NAG9 and ALB） and exposure biomarker （UCd）. BEL value was 5 μg/g creatinine for UB2M as an effect biomarker, consistent with the recommendation of WHO. BEL could be estimated by using the method of BMD. BEL value was 3 μg/g creafinine for UNAG as an effect biomarker. The more sensitive the used biomarker is, the more occupational population will be protected. Conclusion BMD can be used in estimating the biological exposure limit （BEL）. UNAG is a sensitive biomarker for estimating BEL after cadmium exposure.
文摘The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported. The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin, cornea, sclera, anterior chamber and lens of eyeball.The ratios among superficial absorbed dose D (0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6 mm are also obtained with Cross's methods. They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.
基金the Chilean Government and the National Commission for Scientific and Technological Research (CONICYT) for supporting this work through the Becas Chile Scholarships
文摘Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A novel approach to develop scientifically defensible levels of safety concern is presented and an example to determine acute and chronic pesticide food safety standard （PFSS） levels for the fungicide captan on strawberries is provided. Using this approach, the chronic PFSS level for captan on strawberries was determined to be 2 000 mg kg-1 and the acute PFSS level was determined to be 250 mg kg-1. Both levels are far above the existing tolerance and MRLs that commonly range from 3 to 20 mg kg-~, and provide evidence that captan residues detected at levels greater than the tolerance or MRLs are not of acute or chronic health concern even though they represent violative residues. The benefits of developing the PFSS approach to serve as a companion to existing tolerances/MRLs include a greater understanding concerning the health significance, if any, from exposure to violative pesticide residues. In addition, the PFSS approach can be universally applied to all potential pesticide residues on all food commodities, can be modified by specific jurisdictions to take into account differences in food consumption practices, and can help prioritize food residue monitoring by identifying the pesticide/commodity combinations of the greatest potential food safety concern and guiding development of field level analytical methods to detect pesticide residues on prioritized pesticide/commodity combinations.
