Cd2+胁迫对文蛤鳃组织SOD、CAT活性及MDA含量的影响

为了解不同质量浓度的Cd2+对水生动物的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和脂质过氧化的影响,以文蛤为研究材料,采用室内模拟试验的方法,依据Cd2+对文蛤96h半致死质量浓度(LC50),设置4个Cd2+胁迫组,胁迫质量浓度分别为0.41 mg/L( 1/32LC50)、0.82 mg/L(1/16 LC50)、1.65 mg/L(1/8 LC50)、3.30 mg/L( 1/4LC50),并设置对照组,每组3个平行.研究不同质量浓度的Cd2+对文蛤鳃组织SOD、CAT活性和MDA含量的影响.结果表明:文蛤鳃组织SOD活性在0.41 mg/L和0.82 mg/L胁迫下,试验前期(0～48 h)呈现诱导效应,试验后期(48～96 h)呈现抑制效应,其余胁迫质量浓度在试验过程中均对文蛤鳃组织SOD活性呈现抑制效应;CAT活性在低质量浓度(0.41 mg/L)胁迫下出现阶段性抑制效应,接着呈现诱导-抑制过程,中高质量浓度在整个过程呈现诱导-抑制的过程;经过96h的胁迫试验,各胁迫组文蛤鳃组织中MDA含量显著上升(p＜0.05),Cd2+对MDA的诱导作用显著且存在剂量-效应关系.     

镉胁迫对节杆菌(Arthrobacter sp.)和芽孢杆菌(Bacillus sp.)生理生化特性的影响

将节杆菌和芽孢杆菌分别暴露于不同质量比的镉溶液中,进行不同暴露时间的急性毒性试验.结果表明,20 mg/kg的Cd(Ⅱ)处理会使节杆菌中还原型谷胱甘肽(GSH)质量浓度显著降低,细胞膜脂质过氧化产物——硫代巴比妥酸活性物质(TBARS)浓度显著升高;0.2mg/kg的Cd(Ⅱ)处理会使芽孢杆菌中GSH质量浓度、过氧化氢酶(CAT)活性显著降低.节杆菌的可溶性蛋白、可溶性糖质量浓度随暴露时间延长而减少,GSH质量浓度、CAT和超氧化物歧化酶(SOD)活性随暴露时间延长而增加,TBARS浓度呈先减后增的变化趋势;芽孢杆菌的可溶性蛋白质量浓度、CAT活性和TBARS浓度呈先增后减的变化趋势,可溶性糖、GSH质量浓度和SOD活性呈先减后增的变化趋势.镉处理对节杆菌和芽孢杆菌具有一定的胁迫作用,两种菌通过启动不同的抗性系统来抵抗外界胁迫.     

爪蟾胚胎致畸实验(FETAX)在检测污染物发育毒性中的应用

爪蟾胚胎致畸实验(FETAX)是一种用于检测污染物发育毒性的有效方法.用CuSO4、CdCl2和三丁基锡(TBTCl)对热带爪蟾(Xenopus tropicalis)胚胎进行48 h暴露.结果表明,对照组胚胎均未出现死亡或畸形现象,Cu2+、Cd2+和TBTCl对胚胎的半致死质量浓度(LC50)分别为0.38 mg/L、4.28 mg/L和3.18 μg/L.48 h后,各暴露组胚胎出现颅面缺陷、眼睛突出、漏斗形嘴、肠道蜷曲、尾巴弯曲、水肿和色素沉着等多种畸形现象.Cu2+、Cd2+和TBTCl对胚胎的半致畸质量浓度(EC50)分别为0.16 mg/L、2.16 mg/L和2.98 μg/L,致畸指数分别为2.38、1.98和1.04.用脱碘酶抑制剂碘番酸(IOP)对非洲爪蟾胚胎进行暴露.36 h后,暴露组胚胎主要出现眼睛异常发育甚至消失等现象,这表明IOP对眼的发育有特定的毒性作用.研究表明,运用热带爪蟾胚胎检测污染物发育毒性的灵敏性并不高于非洲爪蟾(X. laevis)胚胎致畸实验,运用FETAX进行污染物发育毒性的检测并未显示出明显优势,其实验方案还有待进一步改进,但爪蟾胚胎模型在研究污染物特定的毒性机理方面具有较大潜力.鉴于爪蟾胚胎很适合进行分子操作,在现有FETAX实验的基础上增加一些分子生物学指标,将不仅能提高发育毒性效应检测的灵敏性,而且也增加了对污染物特定毒作用模式的解析功能.     

抗生素药物诺氟沙星对锦鲤的毒性效应

为明确抗生素药物诺氟沙星对锦鲤的毒性效应,采用鱼类毒性试验方法,研究了诺氟沙星(Norfloxacin,NFLX)对锦鲤的急性毒性和亚急性毒性效应.结果表明,当NFLX暴露质量浓度达到1 000 mg/L时,NFLX对锦鲤无急性毒性.NFLK暴露15 d,在1 mg/L、5 mg/L、25mg/L和125 mg/L 4个组中,5 mg/L组锦鲤肝脏SOD活性在6d时达到最大(p＜0.01);125 mg./L组MDA含量在15 d时达到最大值(p＜0.01);25 mg/L、125 mg/L组锦鲤肝脏中MDA含量与暴露时间呈正相关,相关系数分别为0.938 1、0.953 5.各组GST活性和GSH质量比均受到不同程度的诱导,1 mg/L组NFLX可使鱼肝GST与GSH产生适应性反应;5 mg/L组诱导GST与GSH效应最为显著,呈现“钟形”变化趋势,5 mg/L很可能是NFLX对GST活性和GSH质量比影响的一个阈值或转折点.鱼肝GPT与GOT活性变化表现出一定的相似性,均呈现先升高后降低的变化规律,其中5 mg/L组被诱导效应最为显著(p＜0.01).5 mg/L很可能是锦鲤适应NFLX暴露和机体中生物酶发挥作用的一个转折点.比较上述抗氧化和转氨酶指标的敏感性和稳定性发现,在NFLX作用下,锦鲤肝脏中GST、GSH两个指标对NFLX的反应比SOD、MDA、GPT、GOT灵敏,变化规律稳定,更适合评价水环境中NFLX暴露的毒性效应.     

铅胁迫对节杆菌(Arthrobacter sp.)和芽孢杆菌(Bacillus sp.)生理生化特性的影响

将节杆菌和芽孢杆菌分别暴露于不同浓度的铅溶液中,并进行不同暴露时间的急性毒性试验。结果表明,500 mg/kg的Pb(II)处理会使节杆菌中的细胞膜脂质过氧化产物——硫代巴比妥酸活性物质(TBARS)浓度显著降低(p0.05),而Pb(II)质量比变化对其他指标无显著影响(p0.05);铅处理会使芽孢杆菌中可溶性蛋白质量浓度、GSH质量浓度和超氧化物歧化酶(SOD)活性显著升高,而过氧化氢酶(CAT)活性显著降低(p0.05)。节杆菌的可溶性糖质量浓度、GSH质量浓度、SOD活性和TBARS浓度随暴露时间延长而显著增加;芽孢杆菌的可溶性糖质量浓度、GSH质量浓度和SOD活性随暴露时间延长而显著增加,TBARS浓度随暴露时间延长呈先增后减的变化趋势,CAT活性也表现出先增后降的变化趋势。铅处理对节杆菌和芽孢杆菌具有一定的胁迫作用,两种菌通过启动不同的抗性系统来抵抗外界胁迫。     

铀胁迫对香根草生理生化指标的影响

采用水培方式研究了不同质量浓度(0、0.1 mg/L、1 mg/L、5mg/L、10 mg/L、20 mg/L)铀胁迫下香根草光合色素质量比、可溶性蛋白质质量比、丙二醛(MDA)含量、抗氧化酶(超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT)活性、非酶物质(非蛋白巯基NPT、谷胱甘肽GSH和植物络合素PCs)含量的变化.结果表明,铀质量浓度为0.1 mg/L和1 mg/L时,可促进香根草光合色素和可溶性蛋白质质量比的增加,但随铀质量浓度增加,光合色素和可溶性蛋白质质量比逐渐下降.铀胁迫诱导香根草体内MDA含量、POD活性和CAT活性呈明显升高的趋势,SOD活性则表现为逐渐下降的趋势.不同质量浓度铀胁迫对香根草根部NPT、GSH和PCs含量无明显影响,铀质量浓度为0.1 mg/L时香根草根部NPT、GSH和PCs含量略有增加;随铀胁迫质量浓度增加,叶片内GSH含量逐渐下降,NPT和PCs含量则逐渐升高.     

稀土元素镧-铜胁迫下蚯蚓的抗氧化防御反应

采用自然土壤染毒法研究了稀土元素镧(La)和铜(Cu)复合污染对蚯蚓体内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响。结果表明,La和Cu复合染毒对抗氧化防御系统产生了一定的联合毒性效应,其联合毒性效应与暴露时间和不同质量比的组合密切相关。不同剂量La与不同背景质量比Cu复合时,低剂量La作用下,SOD活性呈现上升趋势;高剂量La作用下,SOD活性呈现先上升后下降的变化趋势。这表明复合胁迫使蚯蚓受到的环境胁迫作用增强,且复合胁迫超过其耐受阈值。不同剂量La与不同背景质量比Cu复合时POD活性出现明显波动,总体呈逐渐上升趋势,表明复合胁迫使蚯蚓受到的环境胁迫作用增强。不同剂量La与50 mg/kg Cu复合胁迫时,CAT活性先上升后下降,表明La的存在在一定程度上降低了Cu对蚯蚓的毒性效应;不同剂量La与200 mg/kg Cu、600 mg/kg Cu复合胁迫时,蚯蚓受到的环境胁迫作用增强。     

Cd和Pb对鲫鱼超氧化物歧化酶活性的影响

为了解不同浓度Cd2+、Pb2+及其联合胁迫对超氧化物歧化酶(SOD)活性的影响,以鲫鱼为材料,采用急性毒性试验研究了质量浓度为0.5 mg/L、2.0 mg/L、6.0 mg/L的Cd2+溶液和10 mg/L、20 mg/L、40 mg/L的Pb2+溶液及其混合液作用下,24 h、48 h、96 h后鲫鱼肝胰脏SOD活性的变化.结果表明,0.5 mg/L的Cd2+对鲫鱼肝胰脏的SOD活性有促进作用,其余各浓度组的Cd2+和Pb2+对SOD有抑制作用;Cd2+和Pb2+的联合作用比单独作用对SOD的影响大.     

水杨酸对镉、锌复合胁迫下小麦幼苗生长及生理特性的影响

在水培条件下,以辽春10号小麦品种为供试材料,研究了10-4mol.L-1、10-5mol.L-1、10-6mol.L-13种不同浓度的水杨酸(SA)对1mmol.L-1Cd2+、5mmol.L-1Zn2+复合胁迫下小麦幼苗生长及生理特性的影响。结果表明:与对照组(未加SA处理的Cd2+、Zn2+复合污染)相比,经SA处理Cd2+、Zn2+复合胁迫下小麦幼苗地上及地下生物量都有明显增高,特别是10-4mol.L-1SA处理组分别增加23.78%和24.7%;10-4mol.L-1SA处理组小麦幼苗根系活力提高6.74%。在试验第6 d、11 d根系和叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)分别达到峰值且以10-4mol.L-1SA处理组最高;在整个试验期间3个SA处理组过氧化氢酶(CAT)活性始终高于对照,其中10-4mol.L-1SA处理组为对照组的146.6%;SA处理使丙二醛(MDA)含量降低,在试验第11 d,10-4mol.L-1SA处理组叶片和根系中丙二醛含量分别为对照组的85.5%和87.6%。但是在试验第14 d各组小麦幼苗叶片和根系中丙二醛含量全部有所回升。综合来看,不同浓度的SA处理均能提高小麦幼苗的抗氧化酶活性且高浓度SA(10-4mol.L-1)处理效果最明显。这表明,水杨酸能够通过促进保护酶活性的升高,抑制活性氧含量的增加,从而有效缓解Cd2+、Zn2+复合胁迫对小麦的毒害。     

基于整合生物标志物响应法的镉对背角无齿蚌氧化损伤胁迫效应评估

以背角无齿蚌(Anodonta woodiana)为受试生物,在实验室模拟条件下研究了环境浓度Cd~(2+)对其鳃组织与内脏团抗氧化防御系统的影响。结果表明:在不同质量浓度Cd~(2+)暴露下,超氧化物歧化酶(SOD)与谷胱甘肽过氧化物酶(GPx)活性随暴露时间延长具有类似的变化趋势,均表现为低质量浓度诱导、中质量浓度诱导-抑制、高质量浓度抑制的变化趋势;鳃组织中过氧化氢酶(CAT)与GPx具有一定的互补性,但均与SOD间相对独立;丙二醛(MDA)含量随暴露质量浓度增加及暴露时间延长而不断上升;鳃组织与内脏团抗氧化酶活性变化具有明显的时间-效应与剂量-效应关系。整合生物标志物响应(IBR)分析结果表明:Cd~(2+)质量浓度越高,各组织IBR值越大,造成的损伤越大;其中,内脏团抗氧化酶较鳃组织敏感,损伤程度大于鳃组织;Cd~(2+)暴露短时间内各组织IBR值与Cd~(2+)质量浓度间具有较好的相关性,鳃组织决定系数高于内脏团。     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.     

HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

Nighttime pedestrian fatalities: A comprehensive examination of infrastructure,user, vehicle,and situational factors

Introduction: Pedestrian fatalities in the United States increased 45.5% between 2009 and 2017. More than 85% of those additional pedestrian fatalities occurred at night. Method: We examine Fatality Analysis Reporting System (FARS) data for fatal pedestrian crashes that occurred in the dark between 2002 and 2017. Within-variable and before/after examinations of crashes in terms of infrastructure, user, vehicle, and situational characteristics are performed with one-way analysis of variance (ANOVA) and two-sample t-tests. We model changes in crash characteristic proportions between 2002–2009 and 2010–2017 using linear regressions and test for autocorrelation with Breusch-Godfrey tests. Results: The increase in fatal nighttime pedestrian crashes is most strongly correlated with infrastructure factors: non-intersection unmarked locations (saw 80.8% of additional fatalities); 40–45 mph roads (54.6%); five-lane roads (40.7%); urban (99.7%); and arterials (81.1%). In addition, SUVs were involved in 39.7% of additional fatalities, overrepresenting their share of the fleet. Increased pedestrian alcohol and drug involvement warrant further investigation. The age of pedestrians killed increased more (18.1%) than the national average (3.2%). Conclusions: By identifying factors related to the increase in nighttime pedestrian fatalities, this work constitutes a vital first step in making our streets safer for pedestrians. Practical Applications: More research is needed to understand the efficacy of different solutions, but this paper provides guidance for such future research. Engineering solutions such as road diets or traffic calming may be used to improve identified infrastructure issues by reducing vehicle speeds and road widths. Rethinking vehicle design, especially high front profiles, may improve vehicle issues. However, the problems giving rise to these pedestrian fatalities are likely a result of not only engineering issues but also interrelated social and political factors. Solutions may be correspondingly comprehensive, employing non-linear, systems-based approaches such as Safe Systems.     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。     

森林地表火蔓延模拟方法及其计算机实现

进行了森林火蔓延的研究,对传统的经验公式和模型进行改进,明显发现改进的模型有更好的结果,用计算机巧妙准确地实现了模拟模型,在风力不是特别大,地形变化不是特别剧烈时,该模型有较高精度;并结合火蔓延的主要因素（气象因子、气候、地形等）,进行系统分析,写出算地,编制实现地表火蔓延的预测预报计算机系统软件。这对于有效的组织扑救、减少火灾损失、计算森林火灾的损失评估有重要意义。     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

AHP与GA-SVM耦合模型在滑坡预警中的应用*

为了减少滑坡造成的损失,提高滑坡预测的准确性,通过搭建灾害模拟平台获得滑坡的实验数据,在获得多组模拟实验数据后,分析各变量的特性。首先,通过层次分析(Analytic Hierarchy Process,AHP)算法,对滑坡进行危险度划分;然后,通过支持向量机(Support Vector Machine,SVM)建立模型,遗传算法(Genetic Algorithm,GA)再优化SVM参数,提出1种层次分析法与GA-SVM相耦合的模型。研究结果表明:AHP方法划分后的数据,通过GA与SVM结合建立的模型精度较好,实验预测结果与实际结果较为吻合,与单一SVM相比,精度更高,结果更好,更加适用于多变量的复杂非线性滑坡预警。     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Occupational Safety and Health in Finland

In Finland, occupational safety is the responsibility of the employer, while the occupational safety and health laws are enforced by the Labour Inspection Service, an organization of the state. The Labour Inspection is divided in 11 administrative districts, and it employs 360 professionals. They are mandated to carry out site visits without prearranged appointments to inspect safe work situations, working hours, construction safety, or any aspect of accident risks. The inspectors are also mandated to verify the existence of sufficient occupational health services as prescribed by the Occupational Health Services Act for all employees. The occupational health services are typically provided by enterprise-owned medical departments, by mutually owned health care centers, by private practitioners, or by municipal health care centers. The latter are required by law to provide all services as prescribed by the legislation to anyone who comes to the facility. This situation is prevalent in the countryside, where there are very few private caregiving centers. Declaring occupational accidents and disease cases is mandatory, and the Inspection districts examine all accidents to establish causes and consequences, and to initiate prosecution in case of criminal negligence. Labour Inspection Districts are also notified of the new occupational disease cases as they are declared to insurance companies. Insurance for occupational disease, accidents, and death is an obligation of the employer, although they can choose the insurance company. The medical confidentiality between the workers and their occupational health care providers is very strict. Official statistics are maintained by the state Statistics Finland organization, and they may be used, for example, for research purposes by scientific institutes like the Finnish Institute of Occupational Health. Construction industry accounts for 25% of all fatal accidents (120 cases per 1 million working hours), followed by mechanical, wood, metal, machinery, and pulp and paper industry (10% each of fatal accidents) with rates ranging from 100–160 cases per 1 million working hours. There are some 5,000 occupational disease cases per year (rate 22/10,000 employed). The major disease categories include repetitive strain injuries (1,300 cases), respiratory allergies (600 cases), occupational skin diseases (1,000 cases), and 900 cases of noise-caused hearing loss. In 1998, 589 cases of asbestos-related diseases were reported.     

公路隧道火灾逃生疏散研究

以苍岭隧道为背景,首先采用经验计算理论和计算软件building EXODUS相结合的方式,从被困人员的安全疏散时间、高温烟气的影响、隧道横通道的利用率以及人员的疏散行为特性进行了研究。结果表明:中小规模火灾情况下的安全疏散时间控制在8 min之内,高温烟气影响不大,但横通道的利用率不平均,且人员疏散路线相对集中。然后对存在的逃生疏散问题提出针对性建议以及其他相关建议,旨在为更大程度降低事故的严重性和经济财产损失。