长江江苏段抗生素的空间分布特征及典型污染来源分析

利用超高效液相色谱-三重四极杆质谱法,于2021年4月对江苏省长江干流12个监控断面、入江支流116个监控断面表层水中7大类42种抗生素的分布特征和浓度水平进行研究,并开展典型污染来源分析。结果表明,平水期长江干流42种抗生素总质量浓度范围为47.3～92.8 ng/L,处于较低水平;各入江支流抗生素总质量浓度范围为16.2～3 052 ng/L,干支流水体中检出品种以磺胺类、氯霉素类、林可酰胺类及大环内酯类为主;通过差异性比较发现,C市存在磺胺类抗生素污染的典型区域;典型污染溯源分析结果表明,工业废水可能是该地区环境水体中抗生素污染的来源之一。长江江苏段及地表水中各类抗生素普遍检出,虽然抗生素总量水平不高,但由制药废水、畜禽养殖、污水处理厂等污染源引入而引起的长期积累仍是隐患。研究结果为江苏省长江流域水环境抗生素污染控制和管理提供基础数据。     

排气制动下汽车制动失效的坡长临界值计算

针对连续长下坡汽车王制动器失效的现象,研究了在排气制动下汽车下坡制动失效的坡长临界值问题.根据汽车主制动器制动毂温升模型,推导出在山区不同长纵坡路段,排气制动下汽车主制动器制动失效的坡长临界值,提出r伍5%、6%坡道上,采取Ⅳ档排气制动时,维持40km/h的安全稳定车速,主制动器制动失效的坡长临界值分别为3072m和1929 m,为长下坡路段交通安全设施的设计提供了理论依据.     

CRH3C型动车组制动系统车轮滑行保护

本文阐述了高速列车发生滑行的机理及其判断参数,并具体分析了CRH3C型动车组制动系统车轮滑行保护装置的布置及工作原理,同时说明车轮防滑的必要性及意义。     

思考发现

5月29日,被称为“最美司机”的吴斌,在驾驶大客车行驶于沪宜高速时,被迎面“意外”飞来的制动毂残片击中,最终不治身亡。那么,在我们的安全生产工作中,是否也曾有过如此的“意外”？这种“意外”究竟能不能避免？如果能,我们又应该如何避免？希望大家积极投稿,踊跃讨论。     

擦亮生命安全的指示灯

福建漳州往龙岩的高速公路,有一段叫"和溪"的路段,该段高速公路因受山区地形限制,有连续14公里的长下坡,路形弯曲、复杂,路段纵坡度高达5.8%,临近长下坡坡度设计的极限。自通车以来,常有大型货车因下长坡制动失效,冲出路面,车毁人亡,因此被人     

固相萃取?超高效液相色谱?四极杆?飞行时间 质谱法分析地表水中26种农药

利用固相萃取-超高效液相色谱(UHPLC)-四极杆-飞行时间质谱(Q-TOF/MS)法建立了26种农药的快速筛查和检测方法.首先建立了包含26种农药的一级精确质量数及保留时间、二级离子谱库的数据库.通过谱库信息比对,可实现地表水中26种农药的无标准品的情况下定性鉴定.样品经过C18萃取小柱富集、净化,用乙腈-异丙醇(1∶1,V/V)洗脱.采用C18色谱柱分离,0.1%甲酸甲醇溶液(含10 mmol·L~(-1)乙酸铵)和0.1%甲酸水溶液(含10 mmol·L~(-1)乙酸铵)进行梯度洗脱,再利用UHPLC-Q-TOF/MS检测,外标法定量.结果表明,在线性范围内,26种农药的线性关系良好,线性相关系数≥0.994,加标回收率在67.74%—112.3%之间,相对标准偏差(RSD)0.45%—12.2%之间.     

基于模糊综合评判的乘用车制动系统失效风险严重程度分析

为了准确评估乘用车制动系统失效风险严重程度,提高车辆行车安全,对我国汽车制动系统缺陷涉及的部件和失效模式进行了分析,并针对真空助力器和制动管路失效,设计、开展了实车试验。试验数据分析表明,在制动系统不同的失效状态下,平均制动减速度、制动距离和最大踏板力存在明显差异。因此将以上3个指标与制动系统失效模式结合构建事故树,确立了影响制动系统失效风险严重程度的指标体系;利用G1法和模糊综合评判法,得出了制动系统失效风险的严重程度。结果表明,制动系统真空助力器失效的严重程度等级为较高,制动管路泄漏的严重程度等级为高,与实际案例的风险严重程度评估结果一致。     

Using the nematode Caenorhabditis elegans as a model animal for assessing the toxicity induced by microcystin-LR

Among more than 75 variants of microcystin(MC),microcystin-LR(MC-LR) is one of the most common toxins.In this study,the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied.C.elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L.The results showed that MC-LR could reduce lifespan,delay development,lengthen generation time,decrease brood size,suppress locomotion behavior,and decreases hsp-16-2-gfp expression.The endpoints of generation time,brood...     

Induction of chemotaxis to sodium chloride and diacetyl and thermotaxis defects by microcystin-LR exposure in nematode Caenorhabditis elegans

Apart from the liver disruption, embryotoxicity and genotoxicity, microcystin (MC)-LR also could cause neurotoxicity. Nematode Caenorhabditis elegans was explored as a model to study the neurotoxicity. In the present study, we provided evidence to indicate the neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure to C. elegans. As a result, higher concentrations of MC-LR caused significantly severe defects of chemotaxis to NaC1 and diacetyl, and thermotaxis. The neurotoxicity on chemotaxis to NaCl and diacetyl, and thennotaxis from MC-LR exposure might be largely mediated by the damage on the corresponding sensory neurons (ASE, AWA, and AFD) and interneuron AIY. The expression levels of che-1 and odr-7 were significantly decreased (P<0.01) in animals exposed to MC-LR at concentrations lower than 10 μg/L, whereas the expression levels of ttx-1 and ttx-3 could be significantly (P<0.01) lowered in animals even exposed to 1 μg/L of MC-LR. Moreover, both the chemotaxis to NaCl and diacetyl and the thermotaxis were more significantly reduced m MC-LR exposed mutants of che-1(p674), odr-7(ky4), ttx-1(p767), and ttx-3(ks5) than those in exposed wild-type N2 animals at the same concentrations.