8种木本植物对矿渣中重金属的吸收与富集研究

研究通过测定栽培在铅锌矿渣中的8种木本植物体内的Pb、Zn、Cu、Cd含量,分析比较了其吸收和富集4种重金属的能力。结果表明:Pb、Zn、Cu、Cd主要富集在植物根部,只有很少一部分重金属转移到植物地上部组织中,8种植物并非超富集植物,实地植物修复中可选取光皮树、黧蒴栲、楠木以及杜鹃作为修复铅锌污染土壤的潜力树种。     

融合分心维度的驾驶行为可靠性研究

分心驾驶容易影响驾驶行为,进而导致交通事故的问题。用理论建模方法,研究分心对驾驶行为及其可靠性的影响。介绍分心驾驶的定义和维度。基于驾驶行为理论,建立融合分心维度的驾驶行为模型,分析不同分心维度对驾驶行为的影响机理。基于可靠性理论,建立融合分心维度的驾驶行为可靠性模型,分析不同分心维度对驾驶行为可靠性的影响。结果表明:不同维度分心对驾驶行为的影响具有各自特点和交互性;减少影响系数高的分心维度,有助于提高驾驶行为可靠性;多维度分心比单维度分心会更大程度地降低驾驶行为可靠度,应减少或避免复合分心。     

Tetrachloro-1,4-benzoquinone induces apoptosis of mouse embryonic stem cells

Pentachlorophenol(PCP) is a widespread,persistent environmental contaminant,and it is enzymatically activated to form a reactive metabolite,tetrachloro-l,4-benzoquinone(TCBQ).To our knowledge,there is no information about TCBQ toxicity on embryonic stem cells.Here,we demonstrated that TCBQ induced significantly apoptosis of mouse embryonic stem cells in a concentration-dependent manner.We also showed that TCBQ elevated genomic5-hydroxymethylcytosine(5hmC) by affecting ten-eleven translocation(Tet) dioxygenases in mouse embryonic stem cells.We further investigated whether Tet dioxygenases were implicated in TCBQ-induced apoptosis.By depleting all three dioxygenases(Tet1-3),we found that Tet dioxygenases slightly inhibited both early and late apoptosis induced by TCBQ at a low concentration(30 μmol/L).Meanwhile,treated by TCBQ at higher concentrations(40and 50 μmol/L),the total percentage of apoptotic cells was not affected by Tet dioxygenases.However,Tet dioxygenases tended to arrest mouse ES cells to be at early apoptotic stage and to reduce the cells to enter later apoptotic stage.These results indicate that Tet dioxygenases play a role in shaping TCBQ-induced apoptosis in mouse embryonic stem cells.Our study provides new insights into the toxicology of PCP and its reactive metabolite TCBQ.     

博落回对不同化学形态铀的富集特征

为了研究陆生植物博落回（Macleaya Cordata）对不同化学形态铀的富集特征,采用Visual MINTEQ地球化学平衡软件设计了五种含不同化学形态铀[UO₂2+、CaUO₂（CO₃）₃2-、UO₂Cit-、（UO₂）₂（EDTA）₂4-和UO₂HPO₄]的培养液,开展水培试验.博落回在这五种培养液中分别培养1、5、10、15、20和25 d后,测定其株高、根长和干质量,并用电感耦合等离子体质谱仪（ICP-MS）测定其地上部分和根部的w（铀）.结果表明:在不同化学形态铀胁迫下,博落回株高无显著差异,UO₂HPO₄可促进博落回根的生长,而（UO₂）₂（EDTA）₂4-降低了博落回的干质量.并且,博落回根部对不同化学形态铀的富集能力大小顺序为UO₂2+ > UO₂HPO₄ > CaUO₂（CO₃）₃2- > UO₂Cit- >（UO₂）₂（EDTA）₂4-,博落回地上部分对不同化学形态铀的富集能力大小顺序为UO₂Cit- >（UO₂）₂（EDTA）₂4- > UO₂2+ > CaUO₂（CO₃）₃2- > UO₂HPO₄.此外,博落回根部对UO₂2+的富集能力很高,但地上部分很低.添加柠檬酸,培养液中铀的主要化学形态为UO₂Cit-,并且在100 mg/L铀的胁迫下,博落回对UO₂Cit-的生物富集系数和转移系数分别达到0.09和8.53.因此,要提高博落回对铀污染土壤中铀的富集和转移,可添加柠檬酸,促使土壤中铀的形态以UO₂Cit-为主,同时要降低土壤中碳酸盐和磷酸盐的含量.      

两种钝化剂对土壤Pb、Cd、As复合污染的菜地修复效果

通过辣椒种植田间试验,研究了硫酸铁和碳酸钙对土壤Pb、Cd和As复合污染的生物有效性以及对辣椒中Pb、Cd、As迁移与累积的影响.结果表明:(1)硫酸铁和碳酸钙都能显著降低土壤中Pb、Cd的TCLP提取态含量,使土壤中As的TCLP提取态含量显著升高.(2)硫酸铁使辣椒果实中Pb和Cd含量分别降低7.2%~22.9%和2.3%~2.9%,而对As含量没有影响;碳酸钙使辣椒果实中Pb、Cd、As的含量分别降低15.8%~16.3%、11.8%~15.0%、0.03%~53.2%.(3)硫酸铁使辣椒茎到果实中Pb、Cd、As的转运系数分别最大降低16.7%、68.0%、10.2%;碳酸钙使辣椒茎到果实中Pb、Cd、As的转运系数分别最大降低16.7%、51.5%、45.6%.硫酸铁和碳酸钙都能有效降低旱地中Pb、Cd、As向辣椒中迁移,且碳酸钙效果比硫酸铁好.     

Confirmation of a balanced chromosomal translocation using molecular techniques

Investigation of a couple, who had produced three babies with cri du chat syndrome, showed initially that the mother had an apparent deletion of chromosome 5. It seemed likely that she had a balanced chromosomal translocation but it proved impossible to detect the second chromosome involved using routine cytogenetic methods. Molecular techniques using quantitative hybridization dosage studies were performed and these showed that the mother had a double dose of DNA in the suspected delected area of chromosome 5. Further studies, using in situ hybridization techniques, revealed that the missing segment of chromosome 5 had translocated onto the short arms of a C group chromosome and further analysis of prometaphase chromosomes showed the presence of a balanced translocation, 46,XY, t(5;9)(5qter → 5p14.1::9p22 → 9pter;9qter → p22::5p14.1 5pter). As a result of these findings, it was possible to offer prenatal diagnosis to the patient in furture pregnancies, by detecting the presence of a balanced or unbalanced translocation in the fetus using molecular and cytogenetic techniques.     

Securing the Demographic and Genetic Future of Tuatara through Assisted Colonization

Abstract: Climate change poses a particular threat to species with fragmented distributions and little or no capacity to migrate. Assisted colonization, moving species into regions where they have not previously occurred, aims to establish populations where they are expected to survive as climatic envelopes shift. However, adaptation to the source environment may affect whether species successfully establish in new regions. Assisted colonization has spurred debate among conservation biologists and ecologists over whether the potential benefits to the threatened species outweigh the potential disruption to recipient communities. In our opinion, the debate has been distracted by controversial examples, rather than cases where assisted colonization may be a viable strategy. We present a strategic plan for the assisted migration of tuatara (Sphenodon punctatus), an endemic New Zealand reptile. The plan includes use of extant populations as reference points for comparisons with assisted‐colonization populations with respect to demography, phenotypic plasticity, and phenology; optimization of genetic variation; research to fill knowledge gaps; consideration of host and recipient communities; and inclusion of stakeholders in the planning stage. When strategically planned and monitored, assisted colonization could meet conservation and research goals and ultimately result in the establishment of long‐term sustainable populations capable of persisting during rapid changes in climate.     

石墨烯类纳米材料作为药物载体的研究进展及其潜在风险

石墨烯作为一种新兴的二维碳纳米材料,近年来受到了医学领域科学家的高度关注。由于石墨烯类纳米材料具有较大的比表面积,易于表面修饰等优点,目前在药物载体方面的研究发展迅速。随着纳米技术的发展,除了氧化石墨烯外,进一步将还原氧化石墨烯、石墨烯量子点、石墨烯纳米带等石墨烯类纳米材料作为药物载体应用到医学领域。本文综述了石墨烯类纳米材料作为药物载体在医学领域的研究进展,并从石墨烯类纳米材料的相关毒性研究角度,提醒了人们负载药物前后石墨烯类纳米材料的迁移规律对其潜在风险研究的重要性。     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

北京市机动车驾驶员“抢行”行为及影响因素分析

机动车驾驶员的"抢行"行为是我国交通事故的主要原因之一。为探索北京市机动车驾驶员的"抢行"行为特征及其影响因素,编制"抢行"行为量表,修订态度和驾驶技术量表,通过在线网站调查收集了486个有效回答。进而分析了个人信息变量对"抢行"行为、态度以及驾驶技术的影响。方差分析的结果表明,男性、年轻、未婚驾驶员报告了更多的"抢行"行为。相关性分析的结果表明反对违规(文中"违规"特指违反交通法规定的行为)的驾驶员"抢行"行为更少,赞成违规的驾驶员更容易采取"抢行"行为,赞成"车让人"的驾驶员往往采取避让行人的行为。