Household air pollution and lung cancer in China:a review of studies in Xuanwei

Over half of the world's population is exposed to household air pollution from the burning of solid fuels at home. Household air pollution from solid fuel use is a leading risk factor for global disease and remains a major public health problem, especially in low- and mid-income countries. This is a particularly serious problem in China, where many people in rural areas still use coal for household heating and cooking. This review focuses on several decades of research carried out in Xuanwei County, Yunnan Province, where household coal use is a major source of household air pollution and where studies have linked household air pollution exposure to high rates of lung cancer. We conducted a series of case-control and cohort studies in Xuanwei to characterize the lung cancer risk in this population and the factors associated with it. We found lung cancer risk to vary substantially between different coal types, with a higher risk associated with smoky(i.e., bituminous) coal use compared to smokeless(i.e., anthracite) coal use. The installation of a chimney in homes resulted in a substantial reduction in lung cancer incidence and mortality. Overall, our research underscores the need among existing coal users to improve ventilation, use the least toxic fuel, and eventually move toward the use of cleaner fuels, such as gas and electricity.

Phytochemical, Anti-oxidant, Larvicidal, and Antimicrobial Activities of Castor(Ricinus communis) Synthesized Silver Nanoparticles

Objective Castor possesses the medicinal properties. Hence, castor extract has the reducing power agent was used in nanoparticles synthesis. Extract of castor also produces secondary metabolites （phenolics, reducing agent） and exhibits anti-oxidant property, which was used as larvicide and antimicrobial agent. In the present study the silver nanoparticles （AgNPs） were synthesized using aqueous leaf extract of castor. Methods The synthesized AgNPs were characterized with UV-visible spectroscopy and transmission electron microscopy （TEM）. The phenolics, reducing sugar and total sugar were evaluated performing Folin-Ciocalteu reagent method, DNS method and Phenol-sulphuric acid method. Anti-oxidant activity of synthesized nanoparticles was evaluated using DPPH assay. The larvicidal activity of synthesized AgNPs was evaluated against the third instar of Anopheles stephensi and Aedes aegypti. The mortality was observed after 24 h by probit analysis. Further, the antimicrobial activity was reported against Staphylococcus aureus （Gram positive） and Pseudomonas aeruginosa （Gram negative）. Results The UV spectra showed maximum absorbance at 445 nm and TEM analysis indicated spherical shape of nanoparticles with average size of 8.96 nm. The synthesized nanoparticles also possessed anti-oxidant potentials. Thus, it could be used as potential free radical scavenger. The larvae of A. stephensiwere found more susceptible to AgNPs than larvae of A. aegyptL Conclusion Due to the medicinal properties and reducing power activity, in the present study AgNPs have been synthesized using the aqueous leaves extract of castor and access their phytochemical, anti-oxidant, larvicidal and antimicrobial properties.

基于三个职业队列的柴油机尾气与肺癌死亡率的暴露-反应估计

[背景]近来，柴油机尾气（DEE）被列为一种已知的人类致癌物。[目的]根据假设的职业和环境暴露场景，得出DEE与肺癌死亡率的meta暴露-反应曲线（ERC），以及肺癌死亡率的估计寿命超额风险（ELRs）。[方法]根据三项大型职业队列研究（包括两项有关货运行业工人的研究和一项有关矿工的研究）得出的相对危险度（RR），对肺癌死亡率与累积元素碳（EC，为DEE的一个替代指标）暴露进行meta回归分析。根据所得出的风险函数，计算终生职业和环境暴露情况下的ELRs，并计算因DEE导致的年肺癌死亡分数。[结果]线性meta回归模型显示，累计EC每增加1μg/（m^3·年），肺癌死亡率的lnRR值为0．00098（95％CI：0．00055～0．0014）.各研究相对应的lnRRs介于0．00061～0．0012。直到80岁终生职业性暴露于1、10、和25μg／m^3 EC的环境中，每10000人中所对应的超额肺癌死亡人数的估计值分别为17、200和689例。终生暴露于0．8μg／m^3 EC环境中，每10000人中超额肺癌死亡数估值为21例。基于对以往职业和环境暴露的普遍的假设，估计每年约有6％的肺癌死亡可能归因于DEE暴露。[结论]三项美国职业病队列研究的综合数据表明，工作场所和室外空气中常见水平的DEE，可能造成大量额外的肺癌终生风险。这一结果高于美国和欧洲通常可接受的限值：基于职业人群和普通人群的终生暴露，限值通常分别设为1／1000和1／100000。