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861.
Ping Gong Niladri Basu Anton M. Scheuhammer Edward J. Perkins 《Environmental science and pollution research international》2010,17(1):181-186
Background, aim, and scope
Hexanitrohexaazaisowurtzitane (CL-20) is a relatively new energetic compound sharing some degree of structural similarity with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a known neurotoxic compound. Previously, we demonstrated using a noninvasive electrophysiological technique that CL-20 was a more potent neurotoxicant than RDX to the earthworm Eisenia fetida. In the present study, we investigated the effect of CL-20 exposure and subsequent recovery on muscarinic acetylcholine receptors (mAChRs) to further define the mechanism of reversible neurotoxicity of CL-20 in E. fetida.Materials and methods
We used a noninvasive electrophysiological technique to evaluate neurotoxicity in CL-20-treated worms, and then measured how such exposures altered levels of whole-body mAChR in the same animals.Results and discussion
A good correlation exists between these two types of endpoints. Effect on mAChR levels was most prominent at day 6 of exposure. After 7 days of recovery, both conduction velocity and mAChR were significantly restored. Our results show that sublethal concentrations of CL-20 significantly reduced mAChR levels in a concentration- and duration-dependent manner, which was accompanied with significant decreases in the conduction velocity of the medial and lateral giant nerve fibers. After 7-day post exposure recovery, worms restored both neurochemical (mAChR) and neurophysiological (conduction velocity) endpoints that were reduced during 6-day exposures to CL-20 concentrations from 0.02 to 0.22 µg/cm2.Conclusions and perspectives
Our findings support the idea that CL-20 induced neurotoxic effects are reversible, and suggest that CL-20 neurotoxicity may be mediated through the cholinergic system. Future studies will investigate other neurotransmission systems such as GABA, glutamate, and monoamine. Ion channels in the nerve membrane should be examined to further define the precise mechanisms underlying CL-20 neurotoxicity. 相似文献862.
含氟离子和氯离子酸性废水处理技术 总被引:1,自引:0,他引:1
本实验研究了石灰乳和铝酸钠处理废水中的氟离子和氯离子的效果。通过正交实验得出:影响除氟离子效果因素的主次顺序为:pH值>氟离子浓度>反应时间;影响除氯离子效果因素的主次顺序为:氯离子浓度>铝酸钠与氯离子的质量浓度比>反应时间。通过单因素实验得出:在pH=9、反应时间为5 min的条件下,废水中氟离子含量可由370.37mg/L降低到2 mg/L以下,去除率可达99.45%;在铝酸钠与氯离子的质量浓度比为1∶10,反应时间为5 min的条件下,废水中氯离子含量可由503.4 mg/L降低到201 mg/L以下,去除率可达60%。 相似文献
863.
为测定含大量干扰离子的水样中镍的浓度,提出一种改进的分光光度法。即以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出浓度的方法。新方法在不进行修正时,对含Cr6+干扰的水样Ni2+测定的结果,误差较小。多组分的水样测量吸光度误差较大,通过引入修正系数修正后误差大幅下降。方法中Ni2+、Fe3+的吸光度与显色时间基本无关;而对于Mn2+、Cu2+和Cr6+,显色时间应控制在0.5~2.5 min内或10 min外,以保证测得吸光度值的稳定与准确。对组成不同的含Mn2+和Fe3+水样测得的Ni2+浓度分析,变异系数(CV)4.74%,检出限为0.275 mg/L,精确度和精密度较好。同时,这种规避方法还具有其他作用,可以在分析组分的同时粗略算出含量。 相似文献
864.
865.
含油量对餐厨垃圾厌氧发酵的影响 总被引:3,自引:0,他引:3
在35℃条件下,研究了不同含油量(0%、1%、2%、3%、4%、5%)餐厨垃圾中温厌氧消化过程中日产气量、甲烷含量、总固体(TS)、挥发性固体(VS)、干物质产气率等的变化,为后续餐厨垃圾连续发酵的预处理提供参考。结果表明:5%含油量餐厨厌氧发酵周期最长,累计产气量最大,为5800mL。在消化过程中,沼气中甲烷含量先上升后下降,最高可达76%;于物质产气率随含油量增大而增大,依次为497.4、506.1、543.8、554.4、590.7和600.1mL/gTS;5%含油餐厨垃圾的TS和VS去除率最大,分别为34.4%和42.9%。 相似文献
866.
Historical change of heavy metals in urban soils of Nanjing, China during the past 20 centuries 总被引:5,自引:0,他引:5
Two typical areas, including once commercial and residential quarters of Nanjing, China, were studied by investigating soil properties especially heavy metals of soils in various cultural layers formed in different Chinese Dynasties. The age of the soil profiles was dated by both archaeological and 14C chronological methods. The results showed that urban soils in the old commercial/workshop quarter of Nanjing were generally contaminated by heavy metals Cu, Zn, Pb, but their concentration levels varied significantly among the cultural layers formed in different dynasties. The substantial increase of heavy metals appeared in three historical periods, i.e., South Dynasty (222-589 AD), the earlier Ming (1368-1644 AD) and the late Qing (1644-1912 AD) in one area. The tremendous input and storage of heavy metals in soils was explained by the primitive smelting and the strengthened metal processing activities, which might be due to the requirement of weapon making or other industries, in the changing social conditions of the corresponding periods. Soils in the once noble political, cultural centers did not show significant increase of heavy metals. The difference in the distribution pattern of heavy metals revealed the contrasting history of the site uses. The change of contaminant level in soils is believed to be a reflection of various human activities in the city during the past 20 centuries. 相似文献
867.
BingXin Gong 《International Journal of Sustainable Engineering》2016,9(5):345-352
This is a new technique for operating a Stirling heat engine. Theoretically, its thermal efficiency should be greater than 100%. However, it does not violate the first and second laws of thermodynamics; it is not a perpetual motion engine, because the atmospheric pressure can be utilized as the external energy source, which no other existing heat engines can do. This means that the new type of heat engine can offer an immediate and concrete solution to the many energy and climate challenges that we are facing; therefore the reliability and significance of this new type of Stirling heat engine is self-evident. 相似文献
868.
869.
870.
针对H2S污染的严峻形势,构建了包括催化再生装置和生物滴滤器的生物催化氧化装置。该装置以沸石为填料,以氧化亚铁硫杆菌为脱硫菌种,通过微生物和Fe3+的双重氧化作用高效脱除H2S。试验确定了装置的适宜喷淋量和沸石的最佳粒径。在温度为30℃,进气量为0.25 m3/h,进气H2S浓度为2500mg/m3,喷淋量为1000mL/h,喷淋液的pH值为1.97、Fe3+浓度为0.05 mol/L的条件下,出气H2S浓度足以达到GB14554-93规定的一级厂界标准值。试验证明,生物催化氧化法是一种新型高效的脱硫技术,应进一步开展中试研究。 相似文献