盐酸胍诱导的apo-CP43去折叠过程

膜蛋白生物合成与色素组装中蛋白的稳定性可以通过去折叠条件与过程分析得到.利用色氨酸荧光光谱和ANS荧光光谱研究了apo-CP43在盐酸胍条件下的稳定性.色氨酸荧光光谱观测到apo-CP43在盐酸胍作用下去折叠进程的主要特征:荧光强度先是逐渐降低,之后再逐渐升高,而最大荧光发射峰位置则一直持续红移.盐酸胍处理后apo-CP43的F360 nm/F335 nm比值逐渐增大,表明荧光最大发射峰逐步红移.当盐酸胍浓度约为5.5 mol/L时,去折叠比例趋于相对稳定状态,说明此时apo-CP43已经基本完成去折叠.荧光相图法结果显示盐酸胍诱导apo-CP43变性的过程符合三态模型.ANS荧光测定数据显示盐酸胍处理之后最大ANS荧光发射峰位置红移,并且荧光强度逐渐降低.以上数据表明在盐酸胍条件下apo-CP43是一个相对比较稳定的蛋白.     

南京市大气VOCs污染特征及来源解析

利用南京市2022年挥发性有机物（VOCs）在线监测数据,对VOCs污染特征、来源及对臭氧的影响进行了分析研究。结果表明：2022年南京市φ（TVOCs）年均值为25.1×10^-9,其中各组分占比为烷烃＞含氧挥发性有机物（OVOCs）＞氯代烃＞烯烃＞芳香烃＞炔烃。TVOCs及烷烃、烯烃和芳香烃的体积分数季节变化表现为冬季＞秋季＞春季＞夏季,φ（OVOCs）季节变化表现为夏季＞秋季＞春季＞冬季。烷烃、烯烃和炔烃日变化呈“双峰型”特征,芳香烃和氯代烃为“单峰型”。臭氧生成潜势（OFP）贡献总体表现为OVOCs＞烯烃＞芳香烃＞烷烃＞氯代烃＞炔烃,但冬季烯烃的贡献率最高。南京市臭氧生成的关键VOCs物种为乙醛、乙烯、丙烯、间/对-二甲苯和甲苯。正交矩阵因子分解结果显示,机动车尾气、生物质燃烧和工业生产是南京VOCs的主要来源;对南京臭氧生成贡献最大的VOCs来源为溶剂涂料使用和石化行业。     

陕西省城镇污水处理厂进出水中主要离子与重点元素分布特征

污水处理厂出水中主要离子和重点元素的浓度特征及去除效果会影响受纳水体的盐度、碱度等指标,从而影响河湖的生态服务功能,但是这方面的研究长期以来未得到充分关注。在陕西省全境选择51家城镇污水处理厂,测定进水和出水中的钾、钙、钠、镁、氟、氯和硫酸根离子,以及铁、锰、硼、钼、锶等重点元素的浓度。测定结果显示:陕西省城镇污水处理厂进水和出水中的阳离子以钠离子为主,其次是钙、镁离子,钾离子浓度最低;阴离子中,氯离子浓度最大,其次为硫酸根离子。就总离子浓度而言,陕北和关中地区污水处理厂进水的离子浓度普遍高于陕南地区。相关性分析结果显示:在污水处理厂进水中,钠、氟、氯、镁及硫酸根离子相互之间均呈现显著正相关关系;铁、锰在进水中没有表现出明显的相关关系,而在出水中呈现显著的正相关关系。污水处理厂仅能够处理污水中少量的氟、钾和镁离子。铁元素和锰元素在经过污水处理厂的处理后,浓度有所升高。此研究的研究结果可为河湖水化学组成管理决策提供参考。     

磷酸三苯酯对斑马鱼早期生命阶段的神经毒性研究

磷酸三苯酯(triphenyl phosphate,TPP)作为多溴联苯醚类阻燃剂的替代产品,是一类生产和需求量均相当高的有机磷酸酯类阻燃剂,目前已在多种环境介质以及生物体内均有不同程度检出。由于结构和有机磷农药具有相似性,其对生物的神经毒性值得关注。本研究以斑马鱼为实验动物,研究了TPP(5~625%g·L-1)的胚胎发育毒性和行为毒性,并通过检测乙酰胆碱酯酶活性以及神经系统相关基因的转录水平,探讨其可能的毒性机制。研究发现,TPP可导致斑马鱼胚胎孵化时间延长,体长变短,心率变慢。同时,TPP暴露也可以影响斑马鱼幼鱼在持续光照和明暗周期刺激下的游泳行为,表现为低浓度增加而高浓度降低其游泳速度。而TPP暴露后幼鱼乙酰胆碱酯酶活性以及神经发育相关基因转录水平的变化可能是导致其行为毒性的原因。虽然实验中所设定的暴露浓度高于环境中一般浓度,但TPP在短期暴露中所表现出的胚胎和神经发育毒性表明TPP对于水生生物可能存在一定风险,需要进一步研究加以确认。     

Evolving remanufacturing strategies in China: an evolutionary game theory perspective

Environment, Development and Sustainability - Rapid pace of natural resource depletion and environment deterioration is a cause of concern worldwide. Remanufacturing offers a promising option for...     

微波辐射下改性壳聚糖的制备及其絮凝性能

采用微波辐射法合成了壳聚糖-丙烯酰胺接枝共聚物。通过傅立叶变换红外光谱(FTIR)谱图对比分析表明,丙烯酰胺成功地接枝到壳聚糖上,发生了接枝共聚反应;产物的热重-差热(TG-DSC)谱图表明,壳聚糖-丙烯酰胺接枝共聚物的热稳定性比壳聚糖差。壳聚糖-丙烯酰胺接枝共聚物作为絮凝剂处理高岭土悬浊液的最佳条件为:絮凝剂加入量4.0 mg/L,沉降时间20 min,溶液pH 7。处理印染废水时,与壳聚糖相比,壳聚糖-丙烯酰胺接枝共聚物加入量较少而COD去除效果较好。在废水pH为7、絮凝剂加入量为100 mg/L、沉降时间为20 min的条件下,壳聚糖-丙烯酰胺接枝共聚物对废水COD去除率达41.55%。     

三维电极法处理钻井废水影响因素分析

采取电化学法处理某钻井废水,考察了三维电极系统处理钻井废水时,废水浓度、电流密度、处理时间、电解质浓度和pH值对废水COD降解率的影响,实验结果表明,三维电极法处理钻井废水效果显著;增大电流密度、提高电解质浓度和延长处理时间能使COD去除率提高;最佳pH值为9。正交实验得到最优水平组合为A2B3C2D3E4,在此条件下COD去除率为86.56%。     

Dissolved inorganic tin sources and its coupling with eco-environments in Bohai Bay

Dissolved inorganic tin (DISn) and its spatial variation were examined in Bohai Bay seawaters to understand the DISn behavior and pollution in this area. DISn concentration gradually increased with the distance from the coast and showed a slight decrease with the increasing depth from surface water, suggesting the scavenged behavior of tin with an atmospheric input to surface water. Besides, the higher DISn values also were found near the Haihe Estuary inferring that the riverine input was a source of DISn. Based on the data in this study, a preliminary estimate of the tin budget via riverine input and atmospheric deposition has been established. According to our estimate, about 2 × 10⁶ and 8.47 × 10⁵ g/year of tin reach Bohai Bay via rivers and atmosphere. Environmental factors such as suspended particulate material, salinity, total organic matter, pH, nutrients, and phytoplankton had the important influences on DISn distribution. Among them, the negative correlation between DISn and phytoplankton at most stations might indicate the biological uptake of tin.     

New insights into the evaluation of anaerobic properties of sludge: Biodegradability and stabilization

Evaluating anaerobic biodegradability of sludge and then identifying the stabilization of digestate is necessary in sludge treatment and disposal. 48 sludge samples from 24 typical waste water treatment plants (WWTPs) in 11 provinces in China were selected to investigate the relationship between Biochemical Acidogenic Potential (BAP) test and Biochemical Methane Potential (BMP) test. The volatile fatty acid (VFA) production obtained from BAP tests was found linearly related to the ultimate methane production from corresponding BMP tests. Satisfying results were obtained with Pearson correlation coefficient as 0.929 and R² value as 0.76. Furthermore, the physio-chemical characteristics (FCI, SUVA₂₅₄, E₄/E₆) of supernatant, which were associated with humic-like substances (HS), were investigated before and after BMP tests. Through which a new criterion (FCI>1.50, SUVA₂₅₄>1.10, E₄/E₆<4.0) was proposed to evaluate the stabilization level of anaerobic digested sludge.