Low molecular weight organic acids （LMWOAs） are prevalent on the earth＇s surface. They are vital intermediate products during metabolic pathways of organic matter and participate in the tricarboxylic acid cycle dur...Low molecular weight organic acids （LMWOAs） are prevalent on the earth＇s surface. They are vital intermediate products during metabolic pathways of organic matter and participate in the tricarboxylic acid cycle during life activities. Photochemical reactions are pivotal for LMWOAs＇ origination and play a large role in determining their diversity and their ultimate fate. Within the long time that organic matter is preserved in sediments, it can be decomposed and converted to release organic and inorganic pollutants as well as C, N, and P nutrients, which are of potential ecological risk in causing secondary pollution to lake water. The sediment pool is a comprehensive and complex compartment closely associated with overlying water by various biochemical processes, during which LMWOAs play critical roles to transport and transform elements. This article elucidates geochemical behaviors of LMWOAs in the surface environment in details, taking natural water, soil, and aerosol as examples, focusing on reviewing research developments on sources and characteristics, migration and mineralization of LMWOAs and relevant environmental effects. Simultaneously, this review article depicts the categories and contents of LMWOAs or their contribution to DOC in environmental media, and evaluates their importance during organic matter early diagenesis. Through concluding and discussing the conversion mechanisms and influencing factors, the next research orientations on LMWOAs in lake ecosystems are determined, mainly concerning relationships with hydrochemical parameters and microorganisms, and interactions with pollutants. This will enrich the knowledge on organic matter degradation and related environmental effects, and help reconstruct a theoretical framework for organic compound succession and influencing factors, providing basic data for lake eutrophication and ecological risk assessment, conducive to better control over water pollution and proper management of water quality.展开更多
Coal pyrolysis gas from different ranks of coal was monitored on real time basis using photoionization mass spectroscopy. The molecular weight distribution of different products as a function of temperature from vario...Coal pyrolysis gas from different ranks of coal was monitored on real time basis using photoionization mass spectroscopy. The molecular weight distribution of different products as a function of temperature from various coal ranks studied was observed. It was noted that the release of different classes of compounds like phenols, alkenes, alkylated aromatics and aromatic skeletons was temperature dependent. For all the coal ranks at lower temperatures phenols were the main component, with alkenes and alkylated aromatics at slight higher temperatures and aromatic skeletons were released at the highest temperatures studied.展开更多
This study was carried out to find out if alligator pepper can prevent the development of fetal macrosomia in Sprague-Dawley rats fed with high glycemic index diet. Fifteen adult female Sprague-Dawley rats of proven f...This study was carried out to find out if alligator pepper can prevent the development of fetal macrosomia in Sprague-Dawley rats fed with high glycemic index diet. Fifteen adult female Sprague-Dawley rats of proven fertility were acclimatized for a period of two weeks in a well-ventilated laboratory and fed with grower’s mash and water ad libitum. Thereafter, they were randomly placed in separate cages after which a male Sprague-Dawley rat of proven fertility was introduced into each of the cages containing the female rats. They were left in the cages for three days during, which mating was confirmed to have occurred. The male rats were then withdrawn from the female rats, which were placed in separate maternity cages. The female rats were randomly allocated to three groups A, B and C so there were 5 pregnant rats in each group. The rats in group A were fed with 50 g of grower’s mash daily while the rats in groups B and C were fed with 50 g of cooked fermented cassava respectively. All rats were given water ad libitum throughout the duration of the experiment. The rats in groups A and B were intraperitoneally injected with 13.3 ml per Kg body weight of distilled water while the rats in group C were intraperitoneally injected with 13.3 mg/Kg body weight of aqueous extract of alligator pepper respectively. They were observed for 18 - 25 days. The litters of the rats in group B had a significantly higher mean weight than the rats in group A while the litters of the rats in group C had a significantly lower mean weight than the rats in groups B. It was concluded that intraperitoneally injected aqueous extract of alligator pepper, in the first trimester of pregnancy, can prevent the development of fetal macrosomia in Sprague-Dawley rats.展开更多
基金financially supported by the National Natural Sciences Foundation of China(No.41373138,41003055,41261140337)the National Science and Technology Major Special Project(No.2011ZX07212-007)State Key Laboratory of Environmental Geochemistry(No.SKLEG2013404),Institute of geochemistry, Chinese Academy of Sciences
文摘Low molecular weight organic acids （LMWOAs） are prevalent on the earth＇s surface. They are vital intermediate products during metabolic pathways of organic matter and participate in the tricarboxylic acid cycle during life activities. Photochemical reactions are pivotal for LMWOAs＇ origination and play a large role in determining their diversity and their ultimate fate. Within the long time that organic matter is preserved in sediments, it can be decomposed and converted to release organic and inorganic pollutants as well as C, N, and P nutrients, which are of potential ecological risk in causing secondary pollution to lake water. The sediment pool is a comprehensive and complex compartment closely associated with overlying water by various biochemical processes, during which LMWOAs play critical roles to transport and transform elements. This article elucidates geochemical behaviors of LMWOAs in the surface environment in details, taking natural water, soil, and aerosol as examples, focusing on reviewing research developments on sources and characteristics, migration and mineralization of LMWOAs and relevant environmental effects. Simultaneously, this review article depicts the categories and contents of LMWOAs or their contribution to DOC in environmental media, and evaluates their importance during organic matter early diagenesis. Through concluding and discussing the conversion mechanisms and influencing factors, the next research orientations on LMWOAs in lake ecosystems are determined, mainly concerning relationships with hydrochemical parameters and microorganisms, and interactions with pollutants. This will enrich the knowledge on organic matter degradation and related environmental effects, and help reconstruct a theoretical framework for organic compound succession and influencing factors, providing basic data for lake eutrophication and ecological risk assessment, conducive to better control over water pollution and proper management of water quality.
文摘Coal pyrolysis gas from different ranks of coal was monitored on real time basis using photoionization mass spectroscopy. The molecular weight distribution of different products as a function of temperature from various coal ranks studied was observed. It was noted that the release of different classes of compounds like phenols, alkenes, alkylated aromatics and aromatic skeletons was temperature dependent. For all the coal ranks at lower temperatures phenols were the main component, with alkenes and alkylated aromatics at slight higher temperatures and aromatic skeletons were released at the highest temperatures studied.
文摘This study was carried out to find out if alligator pepper can prevent the development of fetal macrosomia in Sprague-Dawley rats fed with high glycemic index diet. Fifteen adult female Sprague-Dawley rats of proven fertility were acclimatized for a period of two weeks in a well-ventilated laboratory and fed with grower’s mash and water ad libitum. Thereafter, they were randomly placed in separate cages after which a male Sprague-Dawley rat of proven fertility was introduced into each of the cages containing the female rats. They were left in the cages for three days during, which mating was confirmed to have occurred. The male rats were then withdrawn from the female rats, which were placed in separate maternity cages. The female rats were randomly allocated to three groups A, B and C so there were 5 pregnant rats in each group. The rats in group A were fed with 50 g of grower’s mash daily while the rats in groups B and C were fed with 50 g of cooked fermented cassava respectively. All rats were given water ad libitum throughout the duration of the experiment. The rats in groups A and B were intraperitoneally injected with 13.3 ml per Kg body weight of distilled water while the rats in group C were intraperitoneally injected with 13.3 mg/Kg body weight of aqueous extract of alligator pepper respectively. They were observed for 18 - 25 days. The litters of the rats in group B had a significantly higher mean weight than the rats in group A while the litters of the rats in group C had a significantly lower mean weight than the rats in groups B. It was concluded that intraperitoneally injected aqueous extract of alligator pepper, in the first trimester of pregnancy, can prevent the development of fetal macrosomia in Sprague-Dawley rats.
文摘白洋淀是雄安新区核心生态功能区,其水生态安全备受关注。本研究采集白洋淀代表性点位的表层沉积物,以青海弧菌Q67(Vibrio qinghaiensis Q67)为受试生物进行急性毒性筛查,以河蚬(Corbicula fluminea)为模型生物开展毒性效应机制解析,典型污染物筛查完成污染物风险评估。通过整合Q67急性毒性分级,河蚬CAT、SOD、AChE、P450、GST活性、MDA含量等生物标志物和掘穴率和虹吸速率个体行为学差异性指标,以及污染物风险分级等4条证据链(lines of evidence,LoE),构建了加权证据法(weight of evidence,WoE)框架,实现对沉积物质量综合评价。结果显示,点位S4(大田庄村)、S7(南刘庄村)和S8(枣林庄村)沉积物对Q67表现急性毒性效应;河蚬转录组分析表明,差异表达基因显著富集于神经信号通路、代谢通路及氧化损伤等相关通路;6项生物标志物指标进一步证实了上述亚致死效应,S6(圈头村)、S7(南刘庄村)和S8(枣林庄村)的综合生物标志物响应指数分别达11.68、15.99和11.13,高于其他点位;行为学指标上,S2(北河庄村)、S4(大田庄村)、S5(端村)、S7(南刘庄村)的掘穴率和虹吸速率均发生显著改变。化学筛查中48种高关注新污染物(含精神类药物、抗生素等)与6种重金属(Cr、Mn、Zn、Cu、Cd、Pb)检测显示,克林霉素(N.D.~43.15μg·kg^(-1))(以干质量dw计,下同)和Cd(0.10~0.68 mg·kg^(-1))存在中度及以上生态风险,为主要风险因子。WoE整合评价表明,邻近城镇的S4(大田庄村)、S6(圈头村)、S7(南刘庄村)点位WoE值较高,沉积物质量相对较差。本研究通过多证据链整合明确了白洋淀沉积物污染特征与关键风险因子,为沉积物污染防控及雄安新区生态安全保障提供数据基础。
