Effects of co-exposure to lead and manganese on learning and memory deficits

Lead (Pb) and manganese (Mn) are common neurotoxins. However, individuals are subject to co-exposures in real life, and it is therefore important to study these metals in combination. Weaning Sprague-Dawley rats were given ad libitum access to drinking water solutions containing Pb (100 mg/L), Mn (2.5 mg/mL) or a mixture, and each treatment had its own minocycline (50 mg/(kg•day)) supplement group. The results showed a significant difference in spatial memory and induction levels of hippocampal long-term potentiation (LTP) in all exposure groups when compared with controls. The combined-exposure group exhibited the most pronounced effect when compared with each of the single-metal exposure groups. Microglia displayed activation at day 3 after exposure alone or in combination, while astrocytes showed activation at day 5, accompanied by decreased expression levels of GLAST, GLT-1, and GS. Furthermore, the levels of glutamate in the synaptic cleft increased significantly. When microglial activation was inhibited by minocycline, the activation of astrocytes and the expression of GLAST, GLT-1, and GS were both reversed. In addition, upon minocycline treatment, hippocampal LTP impairment and cognitive injury were significantly alleviated in each of the exposure groups. These results suggest that combined exposure to Pb and Mn can cause greater effects on cognition and synaptic plasticity when compared to single-metal exposure groups. The reason may involve abnormal activation of microglia leading to excessive regulation of astrocytes, resulting in glutamate reuptake dysfunction in astrocytes and leading to perturbed cognition and synaptic plasticity.     

基于"多规合一"空间规划的环境管控机制研究

本文通过分析新形势下我国空间规划和环境管控的任务和要求变化,探讨空间规划中环境管控的最新要求,分析"生态保护红线、环境质量底线、资源利用上线、生态环境准入清单"(简称"三线一单")与"城镇空间、农业空间、生态空间、生态保护红线、永久基本农田、城镇开发边界"(简称"三区三线")的关系,并在此基础上研究"三线一单"的管控要求在空间规划体系中的约束机制和相关技术要求,提出空间规划中环境管控的落地措施。     

Evaluation of bacterial pathogen diversity, abundance and health risks in urban recreational water by amplicon next-generation sequencing and quantitative PCR

The microbial quality of urban recreational water is of great concern to public health.The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks.To assess the levels of bacterial pathogens and health risks in urban recreational water,we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year.The pathogen diversity revealed by 16 S r RNA gene targeted next-generation sequencing(NGS) showed that 16 of 40 genera and 13 of 76 reference species were present.The most abundant species were Acinetobacter johnsonii,Mycobacterium avium and Aeromonas spp.Quantitative polymerase chain reaction(q PCR) of Escherichia coli(uid A),Aeromonas(aer A),M.avium(16S r RNA),Pseudomonas aeruginosa(oaa) and Salmonella(inv A) showed that the aer A genes were the most abundant,occurring in all samples with concentrations of 10~(4–6) genome copies/100 m L,followed by oaa,inv A and M.avium.In total,34.8% of the samples harbored all genes,indicating the prevalence of these pathogens in this recreational waterbody.Based on the q PCR results,a quantitative microbial risk assessment(QMRA) showed that the annual infection risks of Salmonella,M.avium and P.aeruginosa in five activities were mostly greater than the U.S.EPA risk limit for recreational contacts,and children playing with water may be exposed to the greatest infection risk.Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and q PCR.     

宝鸡市麟游县煤矿区周边农田土壤重金属污染安全评价

文章选取麟游县的北马坊煤矿、郭家河煤矿和北王煤矿为研究区域,对其周边的农田土壤进行野外采样和室内分析,测定Zn、Cr、Pb、Cu、Cd、Hg、As 7种重金属的污染状况。结果表明:测定的7种重金属元素的最大值均超过了陕西省土壤背景值和当地的土壤环境背景值。单因子污染指数评价得出,三矿区周边的土壤Hg元素的污染较严重,局部地区已经达到了重度污染;综合污染指数法评价得出,三矿区均达到了中度到重度污染水平,其中北王煤矿污染水平较高;地质累积指数法评价得出,三矿区Hg元素的累积程度属于中度污染到强污染等级,Cd元素次之。因此3矿区周边的耕地土壤已不同程度的受到重金属的污染,相关部门应该采取一定的措施治理该区的土壤。     

Comparative toxicity of nano-ZnO and bulk ZnO suspensions to zebrafish and the effects of sedimentation, ˙OH production and particle dissolution in distilled water

With the common application of nanoscale zinc oxide (nZnO) and significant potential for its release directly into aquatic environments, it is urgent to carry out research on ecotoxicological impact of nZnO. The characterization of nZnO, the amount of ˙OH in suspensions in the presence of light and the acute toxicity of nZnO and its bulk counterpart suspensions, as well as the acute toxicity of Zn(2+) solution to zebrafish (Danio rerio) at 96 h were studied. It was found that nZnO aggregated into irregular shapes in suspensions, and showed a relationship between its size distribution and concentration. In the presence of light, nZnO suspensions could generate ˙OH, the concentration of which increased with time. Although it was generally thought that ˙OH played a role in the biotoxicity to zebrafish, similar toxicity was observed for the nZnO and bulk ZnO suspensions (96 h LC(50) 3.969 mg L(-1), 2.525 mg L(-1), respectively). Furthermore, the sedimentation of nZnO and bulk ZnO in suspensions, and the accumulation of Zn in zebrafish were studied. The results showed that dissolved Zn(2+), from nZnO and bulk ZnO in suspensions, were toxic to zebrafish, while the aggregation and sedimentation of nZnO suspensions reduced the toxicity of nZnO. However, Zn(2+) may not be the main source of acute toxicity of nZnO and bulk ZnO to zebrafish. The experimental results highlight the importance of a systematic assessment of toxicity mechanisms of metal oxide nanoparticles (NPs) to determine definitively whether their toxicity is caused by nano-effects.     

企业新产品开发程序概述

“劳保企业多年来开发出很多新产品,有的水平很高,没听说执行什么科研程序,不也开发出来吗？”这是笔者常听到的一些声音。然而实际上,很多劳保企业开发新产品只是自发地执行科研程序,更有甚者是凭感觉、经验即感性认识。但单凭经验搞开发,往往带有一定的盲目性,容易走弯路,费时费事多花钱且易造成难以弥补的损失。笔者接触过的几个企业中,都不同程度地存在类似的问题。     

猫跳河流域梯级水库磷的夏季变化特征

调查了我国第一条全流域梯级水电开发的河流——猫跳河中梯级水库对磷的拦截效应。于2007年丰水期7~9月在猫跳河流域采集水库坝前分层水样以及下泄水，分析和测试水样中的总磷和正磷酸盐。结果表明：丰水期猫跳河流域梯级水库内部总磷和可溶性正磷酸盐变化趋势相似，而下泄水的磷含量均大于该水库表层水体的磷含量。在猫跳河流域的梯级水库中，上游水库（红枫湖和百花湖）的磷含量明显高于各下游水库，即猫跳河流域各水库顺水流方向磷含量具有逐渐减少的特征，说明该流域梯级水库开发对于全流域磷具有梯级拦截效应；另一方面，各水库的富营养化指数表明该流域各水库均处于较高的富营养化状态，全流域富营养化状态差别与磷的分布特征相似，表现为顺水流方向减弱的规律。     

包装材料的绿色环保设计

指出了绿色包装的含义 ,阐明了实施绿色包装的重大意义 ,提出了实施绿色包装的主要对策。     

2005年度国家总局报刊工作座谈合在京召开

为贯彻落实安全发展观．总结和交流报刊工作为全国安全生产服务的做法和经验，国家安全生产监督管理总局宣教中心不久前在北京召开了2005年度报刊工作座谈会暨第三届报刊联谊会，总局所属报刊社的有关领导参加了会议。新闻出版总署、国家科技部、北京市新闻出版局主管报刊工作的领导、