Objective:A diagnosis of drowning remains one of the most challenging issues in forensic science,especially for decomposed bodies.Diatom analysis is considered as an encouraging method for diagnosing drowning.In this ...Objective:A diagnosis of drowning remains one of the most challenging issues in forensic science,especially for decomposed bodies.Diatom analysis is considered as an encouraging method for diagnosing drowning.In this study,we developed a drowned rat model using different diatom densities in water.Methods:A total of 120 adult Sprague-Dawley rats were used and divided into six groups,wherein experimental groups 1-5 were drowned rats(group A)and postmortem submersion rats(group B)that were submerged in water with five different Cyclotella sp.diatom densities,while the remaining group was used as a blank control.The combination of microwave digestion and vacuum filtration method was used to accomplish efficient tissue digestion and ascertain higher accuracy of diatom determinations within organs.Results:The abundances of diatoms in the lungs,livers,and kidneys were significantly different.The diatom abundances in the lungs,livers,and kidneys were directly proportional to the water diatom densities,and specific quantitative relationships could be approximated by separate regression equations for each organ type.However,the trends associated with the diatom increases among organs slightly differed.In addition,the diatom abundances in the lungs,livers,and kidneys were all positively correlated.Diatoms were not observed in the postmortem submersion groups nor in the blank control groups.Conclusion:The results of this study provide valuable information for establishing a quantitative diatom framework for informing future forensic medicine efforts.展开更多
Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The re...Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The results of monofactor tests of ironand silicon shawed that Fe-EDTA was bettef than ferric citrate in the culture of these diatoms;that the favourable concentration of Fe-EDTA was about 0.5 mg/L of Fe and that of silicate was 2.5 mg/L of Si or more.The orthogonal test showed that the optimal concentration ratios(mg/L)of nitrogen, phosphorus, iron and silicon were: 5. 0: 0. 25: 0.5: 2. 0 for Cocconeis scutellum var. parva; 2.5: 1.0: 1.0: 2.0 for Amphora coffeaeformis; and 5.0: 0. 15: 0.5: 2.0 for N. mollis.展开更多
基金supported by the Hubei Provincial Natural Science Foundation of China(No.2019CFC861).
文摘Objective:A diagnosis of drowning remains one of the most challenging issues in forensic science,especially for decomposed bodies.Diatom analysis is considered as an encouraging method for diagnosing drowning.In this study,we developed a drowned rat model using different diatom densities in water.Methods:A total of 120 adult Sprague-Dawley rats were used and divided into six groups,wherein experimental groups 1-5 were drowned rats(group A)and postmortem submersion rats(group B)that were submerged in water with five different Cyclotella sp.diatom densities,while the remaining group was used as a blank control.The combination of microwave digestion and vacuum filtration method was used to accomplish efficient tissue digestion and ascertain higher accuracy of diatom determinations within organs.Results:The abundances of diatoms in the lungs,livers,and kidneys were significantly different.The diatom abundances in the lungs,livers,and kidneys were directly proportional to the water diatom densities,and specific quantitative relationships could be approximated by separate regression equations for each organ type.However,the trends associated with the diatom increases among organs slightly differed.In addition,the diatom abundances in the lungs,livers,and kidneys were all positively correlated.Diatoms were not observed in the postmortem submersion groups nor in the blank control groups.Conclusion:The results of this study provide valuable information for establishing a quantitative diatom framework for informing future forensic medicine efforts.
文摘Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The results of monofactor tests of ironand silicon shawed that Fe-EDTA was bettef than ferric citrate in the culture of these diatoms;that the favourable concentration of Fe-EDTA was about 0.5 mg/L of Fe and that of silicate was 2.5 mg/L of Si or more.The orthogonal test showed that the optimal concentration ratios(mg/L)of nitrogen, phosphorus, iron and silicon were: 5. 0: 0. 25: 0.5: 2. 0 for Cocconeis scutellum var. parva; 2.5: 1.0: 1.0: 2.0 for Amphora coffeaeformis; and 5.0: 0. 15: 0.5: 2.0 for N. mollis.
