全氟辛烷磺酸(PFOS)对人骨髓间充质干细胞PPARs亚型及分化潜能的影响

过氧化物酶体增殖物激活受体(peroxisome proliferators-activated receptors,PPARs)是全氟辛烷磺酸(perflurooctane sulfon-ate,PFOS)的首要分子靶标,但PPARs各亚型在PFOS毒性效应中可能产生不同调控作用,相关机理并不清楚.本研究采用人骨髓间...     

Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure

There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their manure as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOCs) and greenhouse gases (GHGs). We report measurements of alcohols, volatile fatty acids, phenols, and methane (CH4) emitted from nonlactating (dry) and lactating dairy cows and their manure under controlled conditions. The experiment was conducted in an environmental chamber that simulates commercial concrete-floored freestall cow housing conditions. The fluxes of methanol, ethanol, and CH4 were measured from cows and/or their fresh manure. The average estimated methanol and ethanol emissions were 0.33 and 0.51 g cow(-1) h(-1) from dry cows and manure and 0.7 and 1.27 g cow(-1) h(-1) from lactating cows and manure, respectively. Both alcohols increased over time, coinciding with increasing accumulation of manure on the chamber floor. Volatile fatty acids and phenols were emitted at concentrations close to their detection limit. Average estimated CH4 emissions were predominantly associated with enteric fermentation from cows rather than manure and were 12.35 and 18.23 g cow(-1) h(-1) for dry and lactating cows, respectively. Lactating cows produced considerably more gaseous VOCs and GHGs emissions than dry cows (P < 0.001). Dairy cows and fresh manure have the potential to emit considerable amounts of alcohols and CH4 and research is needed to determine effective mitigation.     

Effects of sodium bisulfate on alcohol, amine, and ammonia emissions from dairy slurry

Sodium bisulfate (SBS) is extensively used in the poultry industry to reduce ammonia and bacterial levels in litter. It is also used in the dairy industry to reduce bacterial counts in bedding and ammonia emissions, preventing environmental mastitis and calf respiratory stress. The present study measured the effect of SBS on the air emission of ammonia, amine, and alcohol from a dairy slurry mix. Amine flux was undetectable (<5 ng L(-1)) across treatments. Application of SBS decreased ammonia, methanol, and ethanol emissions from fresh dairy slurry. Ammonia emissions decreased with increasing levels of SBS treatment. The 3-d average ammonia flux from the control (no SBS applied) and the three different SBS surface application levels of 0.125, 0.250, and 0.375 kg m(-2) were 513.4, 407.2, 294.8, and 204.5 mg h(-1) m(-2), respectively. The ammonia emission reduction potentials were 0, 21, 43, and 60%, respectively. Methanol and ethanol emissions decreased with an increase in the amount of SBS applied. The 3-d average methanol emissions were 223.7, 178.0, 131.6, and 87.0 mg h(-1) m(-2) for SBS surface application level of 0, 0.125, 0.250, and 0.375 kg m(-2), with corresponding reduction potentials of 0, 20, 41, and 61, respectively. Similar emission reduction potentials of 0, 18, 35, and 58% were obtained for ethanol. Sodium bisulfate was shown to be effective in the mitigation of ammonia and alcohol emissions from fresh dairy slurry.     

生态环境脆弱地区油气田开发生态保护措施探讨

我国许多油气田处于生态环境脆弱地区,石油开采以及油气集输、储运等工程对生态环境的影响非常突出。文章依据生态保护的原则提出了油气田开发规划、设计、施工以及施工后几个阶段应当采取的生态保护措施,同时还提出了施工结束后的一些生态恢复措施,以供借鉴。     

新型除磷混凝剂的研制与应用＊

实验以处理金属表面所产生的磷化废水为研究对象,系统地分析了在新型混凝剂的使用过程中,pH值、温度、石灰投入量、沉降时间、助剂A等因素对脱磷效果的影响。结果表明,含磷量为18mg/L、COD为300mg/L、SS为150mg/L、pH值为5.7～6.5的废水,石灰投入量为300mg/L、沉降时间为10min左右、温度为25℃、pH值调节至9.0、加入5mL助剂A处理后,废水中磷含量为0.25～0.35mg/L、COD为80mg/L、SS为60mg/L,满足《污水综合排放标准》(GB8978—1996)中的一级标准。     

相对湿度对烟气脱硫及烟气监测的影响

烟气脱硫是目前国际上广泛采用的控制二氧化硫的成熟技术,其中半干法烟气脱硫工艺在电厂烟气脱硫装置中占到20%～30％。该工艺的核心是将燃煤烟气绝热增湿,以促进氢氧化钙与二氧化硫反应而进行的。其衡量指标之一为烟气相对湿度,烟气湿度大,烟气脱硫效果好,但不利于烟气排放。为此,本文分析了相对湿度的概念、对脱硫的影响,同时分析了相对湿度对烟气监测的影响,并提出了相应的解决办法。     

几种络合态铜对彩虹方头鱼的生物有效性

通过暴露实验和化学形态计算方法研究了彩虹方头鱼(Ｐａｒａｃｈｅｉｒｏｄｏｎｉｎｎｅｓｉ)对四种铜络合物的吸收．结果表明,络合态铜可被彩虹方头鱼吸收,但对络合态铜的吸收率显著低于对非络合态铜的吸收率,在其它形态铜含量基本恒定的条件下,铜吸收量随络合态铜含量的增加而呈线性增加趋势．不同络合态铜的有效性也有显著差别,条件稳定常数越高,则越不容易被吸收．由于铜暴露导致的粘液分泌量的变化从另一侧面证实了络合态铜的可吸收性．     

A new intelligent electronic nose system for measuring and analysing livestock and poultry farm odours

This paper introduces a new portable intelligent electronic nose system developed especially for measuring and analysing livestock and poultry farm odours. It can be used in both laboratory and field. The sensor array of the proposed electronic nose consists of 14 gas sensors, a humidity sensor, and a temperature sensor. The gas sensors were especially selected for the main compounds from the livestock farm odours. An expert system called “Odour Expert” was developed to support researchers’ and farmers’ decision making on odour control strategies for livestock and poultry operations. “Odour Expert” utilises several advanced artificial intelligence technologies tailored to livestock and poultry farm odours. It can provide more advanced odour analysis than existing commercially available products. In addition, a rank of odour generation factors is provided, which refines the focus of odour control research. Field experiments were conducted downwind from the barns on 14 livestock and poultry farms. Experimental results show that the predicted odour strengths by the electronic nose yield higher consistency in comparison to the perceived odour intensity by human panel. The “Odour Expert” is a useful tool for assisting farmers’ odour management practises. Supported by Ontario Pork, Natural Sciences and Engineering Research Council (NSERC), and Ontario Ministry of Agriculture and Food (OMAF) of Canada.     

Metal release from stainless steel particles in vitro-influence of particle size

Human inhalation of airborne metallic particles is important for health risk assessment. To study interactions between metallic particles and the human body, metal release measurements of stainless steel powder particles were performed in two synthetic biological media simulating lung-like environments. Particle size and media strongly influence the metal release process. The release rate of Fe is enhanced compared with Cr and Ni. In artificial lysosomal fluid (ALF, pH 4.5), the accumulated amounts of released metal per particle loading increase drastically with decreasing particle size. The release rate of Fe per unit surface area increases with decreasing particle size. Compared with massive sheet metal, fine powder particles (<4 microm) show similar release rates of Cr and Ni, but a higher release rate of Fe. Release rates in Gamble's solution (pH 7.4), for all powders investigated, are significantly lower compared to ALF. No clear trend is seen related to particle size in Gamble's solution.