The associations between the environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk and progression

Polychlorinated biphenyls(PCBs) are chlorinated biphenyl compounds with wide applications in the industry.In spite of a ban on their production in the late 1970s,PCBs,as a group of POPs,are still persistent and widely spread in the environment,posing potential threats to human health.The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo,animal and epidemiologic studies.Initial investigations indicated higher levels of PCBs in mammary tissues or sera cor...     

Effect of binder on the properties of iron oxide sorbent for hot gas desulfurization

The most difficult problem in hot gas desulfurization in Integrated Coal Gasification Combined Cycle (IGCC) is the pulverization of sulfur removal sorbents. Appropriate binders for hot gas sulfur removal sorbents can solve the pulverization problem. In this paper, six sorbents with binders of different argillaceous minerals were prepared by mechanical mixing method. Desulfurization behavior for hot gas desulfurization sorbents was investigated in a fixed-bed reactor. Result showed that sorbent NTKW2 with binder of clay had a better sulfidation performance. NTKW2 had a more stable performance than other sorbents in the continuous sulfidation-regeneration cycles. Sulfur capacity of sorbent remained the same in each cycle. The desulfurization efficiency and mechanical strength of NTKW2 were the best among the tested sorbents. The behavior of NTKW2 at different temperatures showed different performances, and the best reaction temperature was 550 ℃. Higher heat stability, sulfur capacity and desulfurization efficiency were found on NTKW2 in six continuous sulfidation-regeneration cycles.     

Study on the supramolecular systems of two basic violets with cyclodextrins by MWNTs/Nafion modified glassy carbon electrode

The electrochemical properties of two basic violets(methyl violet and ethyl violet) at the MWNTs/Nafion modified glassy carbon electrode were investigated.The redox of the basic violets is two-electron and two-proton process,and methyl violet presents stronger electron transfer capacity than ethyl violet.Meanwhile,the inclusion constants of the two basic violets with five CDs were determined by differential pulse voltammetry(DPV).The two basic violets and CDs can form 1:1 complexes. The inclusion capacit...     

Study on the inclusion interactions of berberine hydrochloride and cucurbit[7] by spectrofluorimetry

The inclusion interaction between berberine hydrochloride(BRH) and cucurbit[7](CB[7]) has been studied by spectro-fluorimetry. The result showed that CB[7]interaction with BRH to form a stable inclusion complex with an association constant of 9.57×10~4 L/mol and the fluorescence intensity of the complex was enhanced in 17 times higher than that of the studied drug itself. Based on the significant enhancement of fluorescence intensity of B RH in inclusion complex,a spetrofluorimetric method with high sens...     

Voltammetric determination of isoproterenol using a 5-amino-2’,4’-dimethoxybiphenyl-2-ol modified carbon nanotube paste electrode

A new electrochemical sensor for determination of isoproterenol(IP) is described.The sensor is based on carbon paste electrode (CPE) modified with 5-amino-2’,4’-dimethoxybiphenyl-2-ol(5ADMB) and takes the advantages of carbon nanotubes(CNTs). Under the optimum pH of 7.0,the oxidation of IP occurs at a potential about 210 mV less positive than that of the unmodified CPE. The oxidation currents increased linearly with two concentration intervals of IP,one is 0.09 to 20.0 |xmol/L and,the other is 20.0 to 400.0μmol/L.The detection limit(3σ) obtained by square wave voltammetry(SWV) was 39.0 nmol/L.The practical application of the modified electrode was demonstrated by determining IP in IP ampoule,urine and human blood serum samples.     

珠江三角洲夏季臭氧区域污染及其控制因素分析

2006年夏季,在珠江三角洲(简称珠三角)开展了一次大型野外综合空气质量观测实验.实验包括了珠三角现有的环境监测网络和两个额外设置的超级观测站.本文基于环境监测网络的观测结果对区域臭氧污染状况和污染过程进行了分析,对各站点所记录的气团光化学属性进行了诊断.结果发现,两个超级站点分别对应着污染城市地区和下风向远郊区的光化学条件,它们较好地覆盖了区域尺度上主要的臭氧高值区.使用基于观测的模型对超级站上臭氧的光化学产生过程及臭氧控制区进行了分析.结果显示,第一,模式中的醛类化学和缺失的HONO化学对于臭氧光化学产生具有重要影响;第二,在城市地区,臭氧的光化学产生速率主要受人为源排放碳氢化合物控制;而在城市远郊区,臭氧的光化学产生速率主要受NO控制;第三,重要的人为源排放的碳氢化合物是烯烃和芳香烃.使用O′x和NOz的回归结果对臭氧产生效率进行了估算,发现城市和郊区的数值存在显著差异(分别为2.1和7.8),这从侧面支持了模型对于城市和郊区臭氧控制区属性的判断.     

司帕沙星氯代物的制备及荧光性质研究

司帕沙星在酸性介质中与亚硝酸反应 ,其重氮盐在氯化亚铜存在下 ,继而与氢氯酸反应生成一种较司帕沙星荧光响应值高 1 1 0倍的强荧光物质 ,采用元素分析、红外光谱和质谱对其衍生物的结构进行了表征。结果表明 ,司帕沙星的荧光强度与其喹啉环 5 位上的氨基密切相关 ,本文还对司帕沙星的荧光自猝灭及氯代荧光增敏机理进行了探讨。     

病毒性肝炎动物模型的研究

病毒性肝炎动物模型的研究李菁菁，陈乾生广东省实验动物监测所（广州市新港西路１０５号５１０２６０）人类许多疾病的研究进展在一定程度上依赖于动物模型的建立。实验动物模型对人类病毒性肝炎的致病机理、传播途径和病毒复制机制的研究以及免疫预防和疫苗研究起了相当...     

火焰原子吸收光谱测定微量锗的研究

本文研究了空气－乙炔火焰原子吸收分光光度法测定饮料及灵芝酒中微量金属元素锗。该法线性范围宽（５０－３００μｇ／ｍｌ），选择性强，并有良好的精密度和准确度。样品加标回收率为９７．９－１０３．４％，变异系数１．４％。本方法适用于保健滋补饮品中锗的分析。     

桩基小应变检测中混凝土强度等级判断结果的准确性分析

对桩基小应变检测原理及混凝土强度的准确性进行了分析，提出了针对性的建议，以提高对检测结果的综合判断能力。