An investigation of methods for enriching trophoblast from maternal blood

Trophoblast deportation is known to occur in normal human pregnancy, but it is not yet clear whether these cells routinely enter the maternal peripheral circulation and are available as a source of fetal DNA for non-invasive prenatal diagnosis of genetic disorders. To resolve this issue requires an efficient method of enriching trophoblast from maternal blood combined with a means to confirm its identity. Five different techniques were tested on ten retroplacental blood samples to determine the most sensitive and operator-efficient method. Lysis of red cells alone gave the best recovery of trophoblast but had to be discounted, together with Ficoll density gradient centrifugation, due to the very low purity and the excessive time required. Fluorescence-activated cell sorting (FACS) of pre-enriched trophoblast resulted in the lowest recovery rate (8 per cent) despite a 3250-fold enrichment and a very high purity. Immunomagnetic beads (Dynabeads) coated with anti-CD 16 antibody proved to be the best method for the subsequent immunocytochemical characterization of deported trophoblast. However, IO beads coated with anti-CD45 antibody may be more useful for isolating trophoblast for prenatal diagnosis due to the high purity, enrichment (32-fold), and recovery rate (78 per cent) obtained with this method.     

华南玄武岩红土化过程中微量元素地球化学

广东、海南的玄武岩．在强烈的红土化过程中．元素在红土剖面中发生迁移和残留、贫化和富集。根据红土化过程中元素的地球化学性状，将元素划分为活泼元素和不活泼元素两大类。并首次采用了元素它集因子这个概念来探讨红土化过程中微量元素的地球化学行为。最后讨论了红土化过程小金的表生富集作用。     

characteristics of PM2.5 in rural areas of southern Jiangsu Province, China

Introduction Anumberofstudiesabroadhavedemonstratedthat atmosphericfineparticulatematter(PM2.5,dp<2.5μm)is notonlyassociatedwithatmosphericvisibilityreductionbut alsohasaclearcorrelationwiththenumberofdailydeathsandhospitalizationsasaconsequenceofpulmonarydisease(Chan,1997;Christoforous,2000;Schwartz,1996;Wilson,1997).On18July,1997,theU.S.EnvironmentalProtectionAgency(USEPA)promulgatednewandsevere standardsforfineparticulates(PM2.5)withthesizebelow2.5μm(15μg m3asannualaverage,65μg m…     

A novel technology for quick acclimation of an anaerobic microbial consortia used for biodegrading teraphthalic acid (TA)

ＩｎｔｒｏｄｕｃｔｉｏｎＴｅｒａｐｈｔｈａｌｉｃａｃｉｄ (ＴＡ)ｉｓｏｎｅｏｆｔｈｅｐｅｔｒｏｃｈｅｍｉｃａｌｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｓｙｎｔｈｅｓｉｓｏｆｐｏｌｙｅｓｔｅｒｆｉｂｅｒ,ｖｉｄｅｏｆｉｌｍｓａｎｄｏｔｈｅｒａｐｐｌｉｃａｔｉｏｎｓ .Ｓｉｎｃｅｂｉｓ (2 ｅｔｈｙｌｈｅｘｙｌ)ｐｈｔｈａｌａｔｅ ,ｄｉｅｔｈｙｌｐｈｔｈａｌａｔｅａｎｄｄｉｍｅｔｈｙｌｐｈｔｈａｌａｔｅｈａｖｅｂｅｅｎｃｌａｓｓｉｆｉｅｄａｓｐｒｉｏｒｉｔｙｈａｚａｒｄｏｕｓｃｏｍｐｏｕｎｄｓｂｙＥＰＡｏｆｔｈｅ…     

淮河流域平原区第四系含水层划分及特征分析

以中国地质调查局资助的《淮河流域环境地质调查》项目为依托,对收集到的区域基础地质和水文地质资料进行了二次开发。并根据近三年来淮河流域环境地质调查项目新取得的水文地质钻孔资料、水化学及同位素样品分析结果,科学地对淮河流域平原区第四系含水层进行了划分和印证,结合项目阶段研究成果,对淮河流域平原区第四系含水层特征进行了初步分析和总结。     

Effect of free-air CO2 enrichment on nematode communities in a Chinese farmland ecosystem

At a rice-wheat rotational free-air CO2 enrichment(FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 μl/L 200 μl/L).32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.     

厌氧折流板反应器处理有毒废水及其污泥特性的研究

在１６．２Ｌ厌氧折流板反应器中，处理以葡萄糖为共基质的含五氯酚钠（ＰＣＰ－Ｎａ）有毒废水，进水ＣＯＤ为１１００－１２００ｍｇ／Ｌ，ＨＲＴ为１d。结果表明，ＡＢＲ 对有毒物负荷变化的适应能力强，当进水ＰＣＰ－Ｎa小于８ｍｇ／Ｌ时，出水ＣＯＤ在８０ｍｇ／Ｌ以下，ＰＣＰ－Ｎa在０．２ｍｇ／Ｌ以下，运行稳定。在有毒物低于抑制浓度 下反应器内参形成颗粒污泥，颗粒污泥表面为发酵产酸菌，内部为产甲烷菌，自身形成良好     

谈双鸭山市气象特征及地形特征对空气质量的影响

双鸭山市采暖期污染较重是因为采暖期燃煤量大、低矮分散的面源多的缘故,同时气象因素及地形特征对空气质量的影响也起着相当大的作用,采用2005年空气质量监测数据,进行双鸭山市气象特征及地形特征对空气质量影响分析,得出空气较稳定的取暖期和具有山风、谷风、局地环流的地形特征是形成双鸭山市空气污染的主要原因之一,并针对地形特征及气象特征对双鸭山市空气质量的影响提出空气污染治理措施.     

城市生活垃圾热解产气特性的试验研究

在外热式固定床试验台上,针对城市生活垃圾中的典型组分,进行了不同条件下的热解试验研究。试验测量不同条件下产物的产气量和产气速率,分析了热解气的组分和气体热值。分析发现,物料的挥发分、加热方式以及热解终温等对产气影响大,随温度的增加产气中H2含量逐渐增多,C2H4和C2H6的含量逐渐下降,气体热值有一个最大值。     

太湖藻类状况分析

对太湖藻类发生的内因、外因作了阐述，就有关的环境因子与藻类的关系作了相关分析，对太湖藻类的监测工作提出了建议。