Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?10⁴ L mol^?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.     

Fe(III)–EDDS complex in Fenton and photo-Fenton processes: from the radical formation to the degradation of a target compound

The present work compares the efficiency of homogenous Fenton and photo-Fenton processes in the presence of Fe(III)–EDDS complex under different experimental conditions. 4-tert-Butylphenol (4-t-BP), which is one of the endocrine disrupting chemicals, was used as a model pollutant to investigate the Fenton and photo-Fenton application. The efficiency of homogenous photo-Fenton process was significantly much higher than homogenous Fenton process, which is due to the rapid formation of Fe²⁺ under UV irradiation of the iron complex and the photochemical formation of HO^? from the photolysis of the complex Fe(III)–EDDS. Through the degradation of 4-t-BP, the effect of Fe(III)–EDDS concentration, H₂O₂ concentration, pH, and oxygen was investigated in both processes. Such trend was also correlated with pH calculating the polychromatic Fe²⁺ quantum yield formation at pH 4.0, 6.0, and 8.6. The results showed that at high Fe(III)–EDDS and H₂O₂ concentrations, a negative effect was found. By the way, the Fenton process was found to be enhanced at basic pH. These results can be very useful for the use and optimization of such iron complex in water treatment process as function of different physico-chemical conditions.     

介质阻挡放电协同Ag/Al_2O_3对NO_x脱除的影响

为有效去除发电厂烟气中产生的NOx,利用介质阻挡放电(DBD)产生低温等离子体并结合催化剂Ag/Al2O3进行烟气脱硝实验,研究了在加入乙烯的条件下,平均负载量、催化温度和装置的布置方式对NOx脱除的影响。结果表明,随着负载的增多,NO脱除率呈现先增大后减小的趋势,5种负载量中最佳为1.76%;随着催化温度的升高,NO脱除率同样呈现先增大后减小的趋势,最佳的催化温度为150℃左右;3种不同布置方式对NO和NOx脱除有明显差别,单独催化剂在NO和NOx的脱除率都比较低;单独介质阻挡放电NO脱除率很高,但是NOx很却很低;而两者结合在NO和NOx都达到了很好的效果。     

Enhanced degradation of ortho-nitrochlorobenzene by the combined system of zero-valent iron reduction and persulfate oxidation in soils

ortho-Nitrochlorobenzene (o-NCB) in soil poses significant health risks to human because of its persistence and high toxicity. The removal of o-NCB by both zero-valent iron (ZVI) and chemical oxidation (persulfate) was investigated by batch experiments. The o-NCB removal rate increases significantly from 15.1 to 97.3 % with an increase of iron dosage from 0.1 to 1.0 mmol g^?1. The o-NCB removal rate increases with the decrease of the initial solution pH, and a removal efficiency of 90.3 % is obtained at an initial pH value of 6.8 in this combined system. It is found that temperature and soil moisture could also increase the o-NCB removal rate. The o-NCB degradation rate increases from 83.9 to 96.2 % and from 41.5 to 82.4 % with an increase of temperature (15 to 35 °C) and soil moisture (0.25 to 1.50 mL g^?1), respectively. Compared to the persulfate oxidation system and ZVI system, the persulfate–iron system shows high o-NCB removal capacity. o-NCB removal rates of 41.5 and 62.4 % are obtained in both the persulfate oxidation system and the ZVI system, while the removal rate of o-NCB is 90.3 % in the persulfate–iron system.     

钱塘江引水降氮示范工程的构建和运行研究

针对杭州西湖钱塘江引水低碳高氮的特点,提出以改性水草塘—复合垂直流人工湿地(IVCW)相耦合的生物—生态工艺进行引水处理,对该引水降氮示范工程的构建和运行效果进行了跟踪研究。结果表明,整个稳定运行期间(2012年7月19日至11月19日),耦合工艺对COD、TN、硝酸盐氮、TP的平均去除率分别为52.27%、52.49%、53.69%、52.79%,系统出水满足《地表水环境质量标准》(GB 3838—2002)Ⅳ标准;改性水草塘和IVCW单元作为耦合工艺的两个重要组成部分,在脱氮、除磷方面优势互补,从而共同保证出水水质的稳定;在改性水草塘单元,温度与COD的去除效果呈负相关关系,进水C/N与TN去除效果呈正相关关系;而在IVCW单元,温度与COD、TN的去除效果均呈线性正相关关系,进水C/N与两者的去除效果也呈正相关关系,且对COD的影响要大于对TN的影响。     

两级EGSB反应器处理焦化废水的实验研究

采用两级膨胀颗粒污泥床(EGSB)反应器在微氧条件下处理焦化废水,分别考察了一级和二级EGSB反应器(EGSBⅠ和EGSBⅡ)对污染物的去除效果。结果表明,系统能够高效去除COD和NH3-N,EGSBⅠ主要用于去除COD,EGSBⅡ主要用于去除NH3-N。总水力停留时间(HRT)为24 h(EGSBⅠ12 h+EGSBⅡ12 h),系统对952 mg/L的COD、41.3 mg/L的NH3-N、34.55 mg/L的挥发酚、295.8 mg/L的硫氰化物和0.89 mg/L的氰化物的平均去除率分别为78.1%、81.3%、100%、98.1%和89.9%。出水COD、NH3-N、挥发酚、硫氰化物和氰化物的平均浓度分别为208、7.7、0、5.7和0.09 mg/L。出水NH3-N、挥发酚和氰化物浓度均低于《炼焦化学工业污染物排放标准》(GB 16171-2012)的直接排放限值。     

Comparison of lignin peroxidase and horseradish peroxidase for catalyzing the removal of nonylphenol from water

Concentrations of aqueous-phase nonylphenol (NP), a well-known endocrine-disrupting chemical, are shown to be reduced effectively via reaction with lignin peroxidase (LiP) or horseradish peroxidase (HRP) and hydrogen peroxide. We systematically assessed their reaction efficiencies at varying conditions, and the results have confirmed that the catalytic performance of LiP toward NP was more efficient than that of HRP under experimental conditions. Mass spectrum analysis demonstrated that polymerization through radical–radical coupling mechanism was the pathway leading to NP transformation. Our molecular modeling with the assistance of ab initio suggested the coupling of NP likely proceeded via covalent bonding between two NP radicals at their unsubstituted carbons in phenolic rings. Data from acute immobilization tests with Daphnia confirm that NP toxicity is effectively eliminated by LiP/HRP-catalyzed NP removal. The findings in this study provide useful information for understanding LiP/HRP-mediated NP reactions, and comparison of enzymatic performance can present their advantages for up-scale applications in water/wastewater treatment.     

中国绿色经济发展和机制政策创新研究

通过绿色转型创造新的发展和就业机会对于摆脱经济危机、提升国家竞争力并占据全球制高点和领先地位已经成为全球共识。中国的绿色经济发展将对其未来经济繁荣乃至全球经济发展产生深远影响。转变经济发展方式,实现绿色发展,这不仅是中华民族长远发展的战略性选择和必然需要,也是对全球可持续发展的积极贡献,将对人类发展产生的重要影响。中国正逐步走向绿色发展之路,建设资源节约型社会和环境友好型社会,发展循环经济和低碳经济已经为中国的绿色发展奠定了较为坚实的基础。但是在全球化大背景下,中国正面临各种规模庞大、情况复杂的经济发展、社会转变与环境保护的挑战与机遇,尤其是在宏观层面,绿色发展的体制机制保障尚不健全,制约了中国绿色转型的成效。如何通过恰当的制度创新,进一步推进转型成本效率的提高和体制机制与政策法规质量的改善,加快并深化中国的绿色转型是目前面临的主要问题。本文针对上述问题,系统归纳总结了国际上发展绿色经济的普遍经验以及中国发展绿色经济面临的主要问题和挑战,认为发展绿色经济目前并没有一种通用的模式,解决中国发展绿色经济发展过程中所面临的资源环境制约,必须调整现行以GDP为导向的政府和官员绩效考核体系,平衡目前财政分权体系中财权和事权不对应问题,进一步明确政府和市场的作用及各自起作用的领域,同时,综合应用法律、财政、税收和价格等工具,重视不同手段的综合和协同运用,在不同的发展领域,提出具有适应性和包容性的发展策略,具体来说:①实施"差异化"区域绿色发展战略,针对不同的经济发展和资源环境基础,提出不同的发展重点,同时,建立分区域的绿色发展监测和评估体系;②通过技术进步和管理创新发展绿色农业,以保障农产品安全、生态安全和资源安全为重点,推动农业发展政策、农业生产组织、农业技术服务和农业管理体系的转型;③以资源节约和环境友好为基本原则,实施绿色创新战略,引导和推动工业结构的优化升级;④创建绿色服务业体系;⑤推行绿色消费模式,以绿色消费倒逼绿色经济转型。     

可持续发展新里程:问题与探索——参加“里约+20”联合国可持续发展大会之思考

"里约+20"峰会成果文件《我们憧憬的未来》重申了"共同但有区别的责任"原则;决定启动可持续发展目标讨论进程;肯定绿色经济是实现可持续发展的重要手段之一;决定建立更加有效的可持续发展机制框架;敦促发达国家履行官方发展援助承诺。这是"里约+20"峰会取得的重要成果,这项成果开启了可持续发展的新里程,其理论探索和实践总结将是学术界不懈努力的方向。在《我们憧憬的未来》的框架下,整合现有可持续发展的相关政策,综合考虑各国独特的社会、经济发展和环境保护问题的特殊性,认为可持续发展研究需要在以下6个方面做出努力:①绿色经济的概念、发展模式与政策创新研究,主要包含了绿色经济的内涵;绿色经济与可持续发展之间的关系;绿色经济与就业、脱贫等之间的关系;衡量绿色经济的具体指标体系;对不同区域和不同行业经济发展绿化程度的测度;绿色壁垒的形式以及对我国国际贸易的影响;发展绿色经济对国际政治经济格局的影响;绿色经济的发展模式与政策创新研究等。②自然资本核算、生态补偿机制与政策研究,主要包含了自然资本的内涵;自然资本与可持续发展之间的关系;各种生态服务之间的耦合关系;如何建立基于自然资本核算方法体系的多层次多元化的生态补偿投融资及其运行机制和生态补偿方式;如何从法律、体制、机制、政策等多层面构建一套完整、具有可操作性的生态补偿政策和制度保障体系等。③可持续发展的全球治理机制研究,主要包含了可持续发展领域的国际合作与冲突机制及有效的全球环境治理机制和可持续发展的国际管理体制的研究;中国、巴西、印度等新兴经济体应该如何应对在未来全球可持续发展中面临的压力和责任及经济全球化对于可持续发展的负面影响等。④科技创新与可持续发展研究,主要包含了科技创新对可持续发展的贡献度;各类型产业可持续发展技术(或者是低碳技术、绿色技术等)的识别、评价和预测;可持续发展技术的创新机制研究;如何通过加强可持续技术的研发和应用,促进绿色产业发展和民生改善等。⑤可持续发展的投融资机制研究,主要包含了提高可持续发展中转移支付、生态环境保护专项资金(基金)、生态税、税收差异化等财政手段效率的体制和机制创新问题;如何推进投融资渠道和方式多元化,实现资金供给与资本结构优化的协调互动和资金配置与运作效率的高效互动等。⑥可持续发展利益相关方的有效参与机制研究,主要包含了系统研究可持续发展利益相关者参与机制创新的可行路径,建立中国可持续发展利益相关者参与的分析框架;研究与设计能够在宏观(或共性)层面和微观(或个性)层面有效运行的参与机制;研究可持续发展利益相关者参与机制创新的制度相容性和实践可行性。