Toxicological effect of MPA-CdSe QDs exposure on zebrafish embryo and larvae

Cadmium selenium (CdSe) quantum dots (QDs) are semiconductor nanocrystals that hold wide range of applications and substantial production volumes. Due to unique composition and nanoscale properties, their potential toxicity to aquatic organisms has increasingly gained a great amount of interest. However, the impact of CdSe QDs exposure on zebrafish embryo and larvae remains almost unknown. Therefore, the lab study was performed to determine the developmental and behavioral toxicities to zebrafish under continuous exposure to low level CdSe QDs (0.05-31.25 mg L⁻¹) coated with mercaptopropionic acid (MPA). The results showed MPA-CdSe exposure from embryo to larvae stage affected overall fitness. Our findings for the first time revealed that: (1) The 120 h LC₅₀ of MPA-CdSe for zebrafish was 1.98 mg L⁻¹; (2) embryos exposed to MPA-CdSe resulted in malformations incidence and lower hatch rate; (3) abnormal vascular of FLI-1 transgenic zebrafish larvae appeared after exposure to MPA-CdSe including vascular junction, bifurcation, crossing and particle appearance; (4) larvae behavior assessment showed during MPA-CdSe exposure a rapid transition from light-to-dark elicited a similar, brief burst and a higher basal swimming rate; (5) MPA-CdSe induced embryos cell apoptosis in the head and tail region. Results of the observations provide a basic understanding of MPA-CdSe toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism.     

人类发展指数的修正与可持续发展的替代指标

本文确认了全球社会-生态问题(过度消费,道德危机)的主要根源并提出了新的可持续发展的愿景,重点要关注精神、道德、心理、生理和人的智力开发(而代替以消费为导主的理念)。讨论了人类发展指标不足所涉及到的因素(寿命预期、人均国内生产总值),提出了测量人类可持续发展的替代指标,即:健康人口的比例。生态效率也被建议作为转化可持续发展的必要条件,人的精神,根据生态中心立场(社会-生态幸福)。通过适当的教育和体制政策而实现环境和人类健康、公平和整个人类的发展。     

Detection of transfluthrin and metofluthrin genotoxicity in the ST cross of the Drosophila Wing Spot Test

In this study, different concentrations of transfluthrin and metofluthrin have been assayed for genotoxicity by using the Wing Spot Test on Drosophila melanogaster. Standard cross was used in the experiment. Third-instar larvae that were trans-heterozygous for the two genetic markers mwh and flr³ were treated at different concentrations (0.0103 mg mL⁻¹, 0.103 mg mL⁻¹ for transfluthrin and 6 μg mL⁻¹, 60 μg mL⁻¹ for metofluthrin) of the test compounds. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing’s imaginal discs lead to the formation of mutant clones on the wing blade. Results indicated that two experimental concentrations of transfluthrin and 60 μg mL⁻¹ metofluthrin showed mutagenic and recombinogenic effects in both the marker-heterozygous (MH) flies and the balancer-heterozygous (BH) flies.     

Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: A study on human and plant cells

In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24 h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24 h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent.     

Human Instability in Flood Flows1

Abstract: Loss of human stability in flood flows and consequent drowning are a high personal hazard. In this paper, we review past experimental work on human instability. The results of new experiments by the Flood Hazard Research Centre (FHRC) are also reported. These new results show that low depth/high velocity flood waters are more dangerous than suggested based on previous experimental work. It is discussed how human instability can be related to two physical mechanisms: moment instability (toppling) and friction instability (sliding). Comparison of the test results with these physical mechanisms suggests that the occurrence of instability in the tests by FHRC is related to friction instability. This mechanism appears to occur earlier than moment instability for the combination of shallow depth and high flow velocity. Those concerned to identify locations where high flood flows could be a threat to human life need to modify their hazard assessments accordingly.     

考虑人因差错影响的结构可靠度计算方法

通过对单个或任意多个人因差错影响下构件截面失效概率计算方法的分析讨论,推导出在理想已知条件下的数学解析求解公式;在考虑人因差错对结构参数影响程度的空间离散化后,得出了相应的简化计算方法;并以一个单筋梁的正截面为例进行了失效概率计算和人因差错影响程度分析.在目前人因差错的发生及其影响规律的研究不完善、缺乏必要的数学模型的现实条件下,该方法对人因差错影响下构件截面失效概率的分析计算有一定的实用价值.     

考虑人为因素的可靠性评估

统计数据表明,系统的可靠运行不可忽略人为误操作造成的故障,该故障发生率有时甚至超过设备本身导致的系统故障发生率。将人为因素与设备自身因素造成的系统故障进行对比,分析人为因素造成系统故障后的特点,可得出人为因素的可靠性参数。根据解析法和模拟法的相关理论计算考虑人为因素的可靠性指标,可以看出考虑人为因素的计算结果更加符合实际运行特点,便于相关人员采取对策,保障系统的安全运行。     

航空维修人为差错影响因素分析中的模糊层次分析法

航空维修中的人为差错影响因素分析对于预防事故发生至关重要,如何定量分析及辨识出主要影响因素是亟待解决的问题。为此,结合航空维修实际,提出运用群组模糊层次分析法对人为差错影响因素进行量化排序和分类,归纳细化了影响因素层次体系,并给出了分析计算流程。以一起由维修人为差错所引发的航空事故为例进行了实证分析,结果表明:该方法能够辨识出航空维修中人为差错产生的主要影响因素,进而对制订最优事故预防方案,控制和减少该类事故的发生有积极意义。同时该方法对其他行业中的人为差错主要影响因素辨识有着一定的参考价值。     

商业区与轻轨站厅开口处防火分隔失效时人员安全疏散评估

针对相连接部位开口处的防火分隔失效时人员能否安全疏散进行评估,研讨人员安全疏散评估过程中所采用的定性分析和定量分析方法。以某商场与轻轨站相连接开口处为例,考察当防火分隔耐火性能失效后,商场内人员和轻轨站的人员能否从火灾中得以安全疏散;通过火灾模拟的方法,采用BuildEvac和FDS软件分别对火灾时人员疏散状况和火灾烟气的蔓延情况进行人员疏散模拟和火灾烟气运动模拟。根据模拟计算结果,对商场内人员和轻轨站人员的安全性进行详细分析和讨论,从而得出实例评估结论:当排烟系统正常工作时,即使防火分隔(防火卷帘)失效,火场环境对商业区和轻轨站的人员生命安全在整个疏散过程中均不会构成威胁,所有人员都能安全疏散到安全地点。     

基于层次分析法的Pedersen人因失误模型研究

科技的发展,使机器设备可靠性有了显著提高,工作环境也得到了改善,但由于人的复杂性,人因失误成为主要的致因因素,如何预防和控制人的失误就成为一个非常重要的课题.运用层次分析法的基本原理,结合Pedersen人因失误模型,构建了导致人因失误的层次分析模型,计算结果显示,人在某种状态下承受负荷的能力大小是影响其失误的主要原因.通过实例,证明了计算结果的可靠性,并提出了减少人因失误的建议.