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With quantitative conversion to volatile derivatives,substance such as perfluorooctane sulfonate (PFOS) that is difficult to analyze can be separated by conventional techniques and then be characterized. In this paper,the methods and procedures in which perfluorooctane sulfonic acids were converted to corresponding sulfonic ester by reaction with triethylorthoacetate(TEOA) in the presence of solvent were described,and then PFOS was analyzed as ethyl ester derivatives. Mass spectra (MS) were generated using electron ionization (EI) mode. And the EI spectra of the volatile derivatives show ions characteristic of both the fluorinated hydrocarbon and the sulfonic ester portion of the molecules. 相似文献
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全氟辛磺酸对于爪蟾的甲状腺激素干扰效应 总被引:1,自引:0,他引:1
运用两栖类变态实验(AMA)研究了全氟辛磺酸(PFOS)对于非洲爪蟾(Xenopus laevis)蝌蚪的生长、变态和甲状腺组织结构的影响.结果显示,与对照组相比,7d后,10,50和250μg.L-1PFOS暴露组蝌蚪的后肢长分别减小了17%,11%和18%,蝌蚪的发育延缓了1~2个阶段;19d后,10,50和250μg.L-1PFOS组蝌蚪的体重分别增加了17%,10%和20%,体长分别增加了5%,4%和6%,而10μg.L-1和250μg.L-1PFOS组蝌蚪的后肢长分别减小了12%和13%;暴露组甲状腺组织结构出现滤泡数目减少、上皮细胞增生、胶质减少甚至滤泡溶通等现象.结论是,在本实验浓度下,PFOS对于非洲爪蟾的蝌蚪生长有促进作用,对于变态发育过程却有抑制作用.参照AMA的方法,可以判断PFOS为抗甲状腺激素干扰物. 相似文献
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Perfluorooctane sulfonate (PFOS) and other fluorochemicals in viscera and muscle of farmed pigs and chickens in Beijing,China 总被引:2,自引:0,他引:2
Eleven perfluorinated compounds (PFCs) were determined in tissue samples from farmed pigs and chickens (n=143) that were purchased in Beijing in March 2009. The total PFCs mean concentration was the highest in pig liver (3.438 ng g–1 wet weight (ww)), followed by pig kidney (0.508 ng g–1 (ww)), pig heart (0.167 ng g–1 (ww)), chicken liver (0.098 ng g–1 (ww)), chicken heart (0.050 ng g–1 (ww)), pork loin (0.018 ng g–1 (ww)), and chicken breast (0.012 ng g–1 (ww)). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) was the predominant compound in viscera and muscle of farmed pigs and chickens. In addition, a strong linear correlation (r = 0.932) was observed between the concentrations of PFOS and perfluoroundecanoic acid (PFUnDA) in pig liver. Our preliminary conclusion is that there is little potential risk of exposure to PFCs via the consumption of these products in Beijing. 相似文献
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Temporal trends of perfluoroalkyl substances (PFASs) have been determined in the blood samples from several countries globally including a female population in Sweden recently, yet little is known about the time trends in the blood levels of these compounds in Swedish male populations over recent years. In this study, the fourteen target PFASs consisted of four perfluorosulfonates (PFSAs) and ten perfluorocarboxylates (PFCAs) in the whole blood samples, collected from 153 Swedish elderly men during the period between 2008 and 2010, were analyzed via ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). As the dominant PFASs contaminants in the blood samples, perfluorooctane sulfo- nate (PFOS) showed the highest geometric mean (GM) at 8.5 ng/mL, ranging from 1.7 to 29 ng/mL, while blood perfluorooctanoic acid (PFOA) contained the GM of 1.8 ng/mL, ranging from 0.35 to 6.4 ng/mL. Both the levels of these two compounds were lower than those determined in the blood samples of Swedish elderly pop- ulations derived from the late 1990s. According to the temporal trend analysis, over the three years, the blood levels of PFOS in Swedish male populations declined 16 % per annum, while those of perfluoroundecanoic acid (PFUnDA) increased 6.1% per annum, which were con- sistent with those reported previously for the populations from other countries. 相似文献
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利用聚丙烯酰胺凝胶的垂直管型盘状电泳,对重庆竹犬血清的前白蛋白(Pa)、白蛋白(Alb)、后白蛋白(Po)的多态性进行了检测,并计算它们的基因型频率和基因频率。结果表明,Alb呈现单一的ALBBB型,Pa未出现条带,Po呈现多态性;并且存在PoA-B、PoAA、PoAA-三种表现型,其基因型频率分别为42.86%、42.86%、14.28%;PoA、PoB、PoA-等位基因频率分别为0.500 0、0.214 3、0.285 7。 相似文献
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深圳塘朗山桫椤孑遗种群的遗传分化研究 总被引:1,自引:0,他引:1
应用RRPD标记分析了深圳塘朗山桫椤孑遗种群全部57个个体的遗传变异和进化关系。50个引物共检测到171个位点,其中多态位点10个,多态位点比率5.85%。基于基因频率的Shannon多样性指数平均值为0.0165,Nei基因多样度指数平均值为0.0094,表明该种群的遗传多样性水平极低。对Jaccard相似性系数矩阵用UPGMA法进行聚类分析显示,57个个体可分为4个亚群。RAPD谱带表型的主成分分析(PCA)支持聚类分析结果。根据研究结果讨论了种群的管理和保护策略。 相似文献
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四溴双酚A对鲫鱼血清抗氧化系统的影响 总被引:2,自引:0,他引:2
研究了幼龄鲫鱼(Carassius auratus)体外暴露于四溴双酚A(TBBPA)后,血清抗氧化系统中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)及过氧化氢酶(CAT)活性和还原型谷胱甘肽(GSH)含量分别随暴露剂量和时间的变化.在整个试验剂量范围内,GSH含量被显著抑制;GSH-Px在中低浓度下被显著诱导,高浓度时活性变化不大;SOD、CAT活性在高浓度暴露时显著升高.0.1 mg/L动态暴露中,GSH含量在整个过程中都被抑制,SOD呈先抑制后诱导,GSH-Px在暴露初期和中期被诱导CAT活性则在暴露后期被显著诱导.试验表明在鱼体受到不同程度的氧化胁迫时,可能会倾向于选择不同的应激补偿机制来消除胁迫;GSH对TBBPA十分敏感,可以考虑作为水环境中TBBPA污染的生物监测指标. 相似文献
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采用荧光猝灭光谱、同步荧光光谱研究生物杀虫剂甲氨基阿维菌素苯甲酸盐(Emamectin Benzoate,EB)与牛血清白蛋白(BSA)相互作用的方式及机理.结果表明,EB可动态猝灭BSA内源荧光;在温度为290 K、300 K、310 K时它们的结合常数(Kb)分别为1.38×103L.mol-1、3.91×103L.mol-1和6.38×104L.mol-1,结合位点分别为0.97、1.02和1.32;通过计算热力学参数可推断二者主要靠疏水作用力结合.同步荧光光谱研究表明EB对BSA构象未产生影响,其结合位点更接近于色氨酸. 相似文献
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种群动态是种群生态学研究的核心问题.为深化对太行山猕猴种群生态学的认识,本研究以栖息于太行山猕猴国家级自然保护区天坛山管护区的太行山猕猴王屋-1群(WW-1)为对象,基于野外观察记录,并结合访问调查和文献查阅,整理分析了该群2002年12月至2015年12月的种群参数、个体扩散模式和种群增长方式等.结果显示:1)WW-1群由2002年12月的14只增长至2015年12月的106只;2)WW-1群平均出生率为每年每只成年雌性生产(0.56±0.23)只婴猴,婴猴(1岁)平均死亡率为10.8%±21.0%;3)WW-1群表现出明显的偏雄(male-biased)的个体扩散模式;4)种群呈指数式增长(Nt=13.32×e~(0.153 1(t-2002))),瞬时增长率为0.153 1. 相似文献
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用聚丙烯酰胺凝胶圆盘电泳和光密度扫描法,对摩拉(Murrah)、尼里(Nili-Ravi)及三品系杂交[Ni♂X(Mu♂×Nanning♀)♀]三种母奶水牛血清LDH同工酶谱型、活力及其与产奶量的关系进行了定量测定和”分析。再次确证其同工酶谱型特点是LDH1>LDH2>LDH3>LDH4>LDH5和LDH6的发现。其相对总活力为尼里>摩拉>三品杂。种间LDH1和LDH2的相对百分含量与产奶量呈正相关趋势,LDH3与之正相反,LDH4和LDH5是尼里<摩拉<三品杂。种内其相对总活力和相对百分含量在LDH1的三种牛、LDH2的尼里和三品杂、LDH5的摩拉等均与产奶量呈正相关趋势,而在LDH2的摩拉、LDH3、LDH4、LDH5的尼里和三品杂等则与之正相反。 相似文献
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CAIXiao-hu ZHONGXiang-hao WANGJin-xi HEFei LIUXing-liang 《武汉大学学报:自然科学英文版》2005,10(4):694-700
It analyses the Castanopsis carlesii, Camellia oleifera and Symplocos laurina populations‘ status and role in the Castanop.sis carlesii community basing on the study on the dominant population size structure, survival curve and dynamic. It reveals the Castanopsis carlesi population acts as a main role in the community which maintains the stabilization and renovation of the community. The populations of Camellia oleifera and Symplocos laurina act as a secondary position. The development and succession dynamics of dominant populations is also discussed. The management method is preliminary draw nout which offers a theoretical basis for the evergreen broad-leaved forest restoration and reconstruction in the lower hilly of the west edge of the Sichuan basin. 相似文献
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在大鼠海马脑薄片上电刺激海马Schaffer侧支纤维 ,胞外记录CA1区锥体细胞层诱发群体峰电位 (PopulationSpike ,PS) ,观察灌流谷氨酸 (Glu)和褪黑素 (MEL) 40min ,人工脑脊液冲洗30min对PS的影响 ,结果显示 :不同浓度 ( 1 .0、1 .2 5、2 .5和 5.0mmol/L)的Glu作用下 ,70min末PS值百分比分别为 1 560 .5%、1 50 .7%、1 3.1 %、4.1 % ;并且Glu浓度高时 ( 2 .5或 5.0mmol/L) ,恢复期末增加刺激强度均不能使PS值升高 .不同浓度MEL( 0 .4μmol/L、0 .5μmol/L、0 .6μmol/L、0 .7μmol/L)作用下PS值在 70min内波动幅度随浓度升高而变小 ,70min末PS值百分比分别为1 93.8%、1 2 9%、75.2 % (恢复期末增大刺激强度 ,则可恢复到 1 0 0 % )、97.1 % .上述结果提示 :低浓度Glu( 1mmol/L ,1 .2 5mmol/L)对神经元具有兴奋作用 ;高浓度Glu( 2 .5mmol/L ,5mmol/L)具有神经毒性作用 ;MEL对神经元具有兴奋和抑制双重作用 ,因MEL浓度不同 ,其作用形式会有不同 相似文献
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福田红树林桐花树和秋茄的生长过程研究 总被引:2,自引:0,他引:2
对深圳福田红树林群落两个优势种桐花树(Aegicerascorniculatum)和秋茄(Kandeli-acandel)进行横剖树干解析,研究这两个树种的胸径、地径、树高、材积生长量的年变化规律及形数年变化规律,结果为:胸径、地径、树高、材积生长量呈镊合状曲线态;其年生长量一般在其最大值的50%~98%之间;各种平均生长量随年龄的增加而平缓地增加,近峰值而未及,可见两树种有相当长的成熟及衰老期,它们的现存年龄为20a左右;两树种的基部形数不随年龄的增加而呈规律性的变化,很难确定其经验形数值 相似文献
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湖北后河国家级自然保护区水丝梨种群分布格局 总被引:4,自引:0,他引:4
对湖北后河国家级自然保护区常绿阔叶林水丝梨 (Sycopsissinensis Oliver)群落进行了种群空间分布格局的研究 .分别将种群中的每个个体在样方中进行定位 ,随机选取一系列不同尺度的小样方 ,运用多种指数判定水丝梨在不同取样尺度上的格局类型 .结果表明 :4m× 4m、6m×6m的尺度上为集群分布 ,其余区组为随机分布 ,且各指数判定吻合性较好 .集群分布出现在较小的观测尺度上是缘于微环境异质性诸如光因子、土壤因子、林窗、岩石裸露的影响 .在较大区组上多呈随机分布 ,这与群落内气候和大生境的一致以及长期处于原始自然状态下密切相关 .水丝梨种群的空间分布格局受群落学特征的影响主要体现在群落种类组成和结构上 .水湿因子和土壤因子是影响其生长进而影响其分布格局的主导生态因子 相似文献