Physical and motor development in male and female rat offspring prenatally exposed to gamma radiation

Abstract

The effects of radiation on physical and motor development of male and female rats exposed to ionizing radiation in utero were studied. Rats were exposed to three different doses of radiation (150 rad, 15 rad and 6.8 rad, considered as high, moderate and low doses of radiation respectively) on the 20th day of prenatal life. Exposure to 150 rad contributed to significantly lower body weights of both male and female rat offspring. Upper jaw tooth eruption was delayed in 150 rad treated male offspring, as well as in 15 rad and 150 rad treated female offspring. Cliff‐avoidance response was delayed in 6.8 rad, 15 rad, and 150 rad treated male offspring; and 150 rad treated female offspring. Lower jaw tooth eruption, eye opening, and crawling were not affected by radiation in male or female animals. Results indicate that radiation affected the developmental parameters of both male and female rat offspring, and sex of the offspring played no role in the magnitude of radiation induced damages.     

土壤铅镉铬暴露下赤子爱胜蚓的回避行为和急性毒性

为了评价土壤重金属污染的生态毒理学效应,根据OECD(经济合作与发展组织)试验指南,研究了人工土壤中Pb、Cd、Cr暴露下赤子爱胜蚓(Eisenia fetida)的回避行为和急性毒性. 回避试验结果表明:赤子爱胜蚓产生完全回避反应的土壤w(Pb)、w(Cd)、w(Cr)分别为2 000、120、120 mg/kg. 急性毒性试验的结果表明,土壤Pb、Cd、Cr对赤子爱胜蚓14 d LD₅₀(半数致死浓度)的分别为2 526.05、362.83、229.44 mg/kg. 在检测Pb、Cd和Cr污染土壤时,赤子爱胜蚓回避试验的灵敏度要高于急性毒性试验. 该研究结果揭示出,赤子爱胜蚓的回避行为指标能够成为土壤生态系统风险评价和毒性效应研究的生物标志物预警指标.      

高速公路碰撞能量衰减装置设计与力学性能分析

为有效降低高速公路上车辆与护栏碰撞事故,提高高速公路交通安全性,基于能量衰减装置变形过程中应具有恒定承载力、稳定的破坏模式等性能要求,设计了一种八边薄壁型能量衰减装置。理论分析推导出能量衰减装置的峰值载荷公式,数值模拟研究了装置的力学性能及其影响因素。研究结果表明:能量衰减装置具有恒定承载力、稳定的变形破坏模式和载荷波动性,其几何参数对冲程效率和载荷波动系数性能指标无影响;能量衰减装置的压溃峰值载荷、能量吸能和平均压溃载荷指标随长度和壁厚的减小而减小,压溃峰值载荷、平均压溃载荷指标随边长增加而减小。