基于拉曼光谱的铅致肝细胞生物分子变化研究

利用拉曼光谱技术采集不同铅离子暴露时间(0.5,1.5,3,6,12,24h)、暴露浓度(0.05,0.1,0.5,1,5mg/L)下HepG2细胞的光谱数据,欲探究在不同铅暴露条件下肝细胞的分子变化及其相关机制.研究结果发现,在不同条件下各组细胞的光谱形态基本相同,但部分特征峰的吸光度强度存在差异.经多元统计分析发现,除6h外,同一暴露时间下不同暴露浓度细胞的光谱数据在LD1上均存在离散趋势,并在暴露24h时最明显.细胞内蛋白质、脂质、核酸、类胡萝卜素、碳水化合物等生物分子的特征峰表现出明显差异,但不同类型生物分子发生显著变化的时间并不相同.由此可见铅暴露可损伤肝细胞蛋白质、脂质、核酸、类胡萝卜素的结构并影响其正常功能,这种毒性效应呈剂量-效应关系,且随暴露时间的增加而增加.本研究说明拉曼光谱可以实现铅对肝细胞生物分子变化的相关检测,这不仅为之后的细胞毒理研究提供了新的思路,同时也为环境污染物的安全评价提供了理论依据.     

Se-Ca联合膳食干预缓解Cd诱导小鼠肝肾毒性

为探究Se-Ca联合膳食干预对生物Cd中毒的缓解效果,选取88只BALB/c小鼠,随机划分为19组,在相同饲料Cd暴露浓度下(2mg/kg)分别设置低、中、高浓度的Se和Ca单独和联合膳食干预处理,并观察30d后小鼠的生长发育、肝肾功能、氧化应激状态和组织病理变化.结果显示,Se-Ca联合干预可有效缓解Cd蓄积所致小鼠生长发育迟缓现象,且进一步促进小鼠生长;肝肾功能及氧化应激指标测定结果表明,Se-Ca联合干预对Cd暴露下小鼠肝脏AST、GSH、SOD、GSH-Px和肾脏BUN、MDA、SOD的保护效果优于单一元素干预;联合干预仅需较小剂量即可达到单独Se或Ca干预对肝肾病理损伤的最佳缓解效果.Se-Ca联合膳食干预可有效缓解Cd摄入导致的生长发育缓慢和肝肾毒性,且较之单一元素的干预效果更佳.     

毫米波近炸探测器超宽带电磁脉冲防护加固措施研究

目的 研究毫米波引信近炸探测器超宽带(Ultra-wideband,UWB)电磁脉冲防护加固措施,提高引信的电磁防护能力。方法 利用超宽带辐照试验平台,开展辐照试验,通过测试,确定受损探测器的损伤部位,明确辐照效应机理,并提出针对性加固措施。结果 超宽带电磁脉冲可使探测器出现死机或硬损伤的现象,受试探测器的效应场强阈值在50~80 kV/m。死机可在重启后恢复,而硬损伤为不可恢复现象。结论 毫米波引信近炸探测器对超宽带电磁脉冲较为敏感,锁相环回路是探测器的敏感部位。探测器暴露在辐照场下的射频电路和天线窗口是超宽带能量的主要耦合通道。采取改进元器件布局、更换器件和屏蔽线等加固措施后,探测器超宽带的防护能力有较大提升,证明了加固措施的有效性。     

Effect of Tinospora cordifolia on the reduction of ultraviolet radiation‐induced cytotoxicity and DNA damage in PC12 cells

The safety of Tinospora cordifolia and its potential to protect against ultraviolet radiation‐induced cytotoxicity and DNA damage in PC12 cells were investigated. To evaluate the safety of T. cordifolia, cell viability and agarose gel electrophoresis were carried out using PC12 cells treated with 0 to 100 μg mL^?1 of methanol extract of T. cordifolia. T. cordifolia extracts did not show cytotoxicity ranging 0 to 100 μg mL^?1. In addition, T. cordifolia extracts significantly increased cell viability at 1 ng, 10 ng and 1 μg mL^?1 concentrations in serum‐deprived medium compared to control. To confirm the protective role against UV‐induced damage, PC12 cells alone or in the presence of 10 ng, 100 ng, or 1 μg mL^?1 of T. cordifolia extract were exposed to 250, 270 and 290 nm of UV radiation, which corresponded to doses of 120, 150 and 300 mJ cm^?2, respectively. Treatment with T. cordifolia extracts significantly increased the cell survival rate irradiated at 290 nm. In addition, T. cordifolia extracts significantly reduced cyclobutane pyrimidine dimer formation induced by UV irradiation at all wavelengths. In conclusion, T. cordifolia is not toxic and safe for cells. Our findings can support its application as phototherapy in the medical sector.     

Growth and Foliar Nitrogen Status of Four Plant Species Exposed to Atmospheric Ammonia

A chamber study was conducted to evaluate the growth response and leaf nitrogen (N) status of four plant species exposed to continuous ammonia (NH₃) for 12 weeks (wk). This was intended to evaluate appropriate plant species that could be used to trap discharged NH₃ from the exhaust fans in poultry feeding operations before moving off-site. Two hundred and forty bare-root plants of four species (Juniperus virginiana (red cedar), Gleditsia triacanthos var. inermis (thornless honey locust), Populus sp. (hybrid poplar), and Phalaris arundinacea (reed canary grass) were transplanted into 4- or 8-L polyethylene pots and grown in four environmentally controlled chambers. Plants placed in two of the four chambers received continuous exposure to anhydrous NH₃ at 4 to 5 ppm while plants in another two chambers received no NH₃. In each of the four chambers, 2 to 4 plants per species received no fertilizer while the rest of the plants were fertilized with a 100 ppm solution containing 21% N, 7% phosphorus, and 7% potassium. The results showed that honey locust was the fastest-growing species. The superior growth of honey locust among all species was also supported by its total biomass, root, and root dry matter (DM) weights. For all species there was a trend for plants exposed to NH₃ to have greater leaf DM than their non-exposed counterparts at 6 (43.0 vs. 30.8%; P = 0.09) and 12 wk (47.9 vs. 36.6%; P = 0.07), and significantly greater (P ≤ 0.05) leaf N content at 6 (6.44 vs. 3.67%) and 12 wk (7.05 vs. 3.51%) when exposed to NH₃. Numerically greater leaf DM due to NH₃ exposure was also consistently measured in poplar at both sampling periods. Hybrid poplar, as well as honey locust and reed canary grass, deposited 1.5 to 2-fold greater N in their leaves than red cedar tissues as a result of NH₃ exposure compared to non-exposed plants. Regardless of the effect of NH₃ on foliar color and damage score of the plants, the increase of foliar N content (g 100 g^?1 of fresh foliage weight) after NH₃ exposure at 6 and 12 wk was 0.45 and 0.87 for grass,1.25 and 1.34 for locust, and 2.67 and 6.09 for poplar. However, only honey locust likely benefited from ambient NH₃ as indicated by its consistent leaf color quality and lower damage score, compared with other species that were adversely affected by atmospheric NH₃.     

考虑“双碳”目标与健康损失的区域现役火电机组有序退役研究

火电行业是我国经济社会发展的重要基础和保障，但也是碳排放的主要源头之一。在“双碳”目标约束下，新能源装机将持续增长，而火电机组则面临降碳和退役的压力。以安徽省为研究区域，考虑“双碳”目标与污染导致的健康损失等因素，对全省现役火电机组的计划退役与有序退役方案进行对比分析，为火电行业实现低碳发展提供路径参考。在有序退役方案下，结合初始投资、使用年限、年度发电收益与污染物排放计算出现役机组每年的净现值，并且根据未来安徽省碳排放削减目标，得到优化后的机组退役时间和顺序。结果表明：与常规的计划退役方案相比，有序退役方案使安徽省火电机组退役时间平均提前约5 a，在2060年碳中和之前可实现现役机组全部退役。2020—2060年，现役机组有序退役可累计减少碳排放量12.76亿t；累计减少SO₂、NO_x、PM_2.5排放量分别为1.44万t、2.13万t、0.17万t，比计划退役方案减少8.66亿元的健康损失。机组的有序退役不仅能带来巨大的环境效益与社会效益，也为“双碳”目标的实现提供了有力保障。     

关于国际油污赔偿基金组织索赔手册

介绍了国际油污赔偿基金组织索赔手册的主要内容，包括法律框架、索赔的提出以及可以得到的赔偿等。     

介绍两种震害损失估算方法

本文介绍了两种震害损失估算方法:全概率法和单位面积法。并据此法对宁夏、青海等地震害作了估算。     

山东临沂市集体林权改革环境影响调查研究—以小山口村、魏城村和南垛庄铺为例

本文选取小山口村、魏城村和南垛庄铺三个林权改革试点村作为调查对象,通过描述统计、交叉列联表分析和Ridit分析,就林权改革的方式、林改对经济和环境产生的影响及林权流转三个方面的问题对山东临沂市的集体林权制度改革现状展开调查研究。分析发现,在历经3年的林改中,临沂市始终坚持尊重实际、区别对待,灵活选择林权改革的方式,使当地的林权制度改革受到村民的欢迎。此外,林权改革后,当地的经济收入和生态环境及对林业的投入均有不同程度的提高和改善,村民的营林、护林积极性也大大增加。但是在涉及到林权流转方面的问题时,大部分的村民不能清楚认识到林权的价值,从而使落实处置权的目标短期内难以实现。     

热障涂层对DD6单晶高温合金高周疲劳性能的影响

目的研究电子束物理气相沉积热障涂层对单晶高温合金高周疲劳性能的影响,为热障涂层在涡轮叶片上的应用提供技术支持。方法采用真空电弧镀和电子束物理气相沉积工艺制备YSZ热障涂层,进行900℃条件下高周疲劳性能测试,采用扫描电镜对测试后的试样表面、断口形貌进行观察与分析。结果在900℃、380 MPa条件下,带涂层的DD6单晶试棒循环次数(Nf)超过了107,420 MPa条件下超过了106。通过对DD6单晶试棒断口分析,失效后的带涂层试棒仍以DD6单晶常见滑移解离形式发生破坏。结论高周疲劳性能测试条件下,带YSZ热障涂层的试棒中粘结层率先产生垂直微裂纹,但是裂纹扩展延伸中发生氧化钝化,之后DD6基体沿正常的滑移方向从表面向内部疲劳扩展,带涂层的试棒疲劳裂纹并非由涂层微裂纹直接扩展形成,热障涂层对DD6单晶高温合金高周疲劳性能影响较小。