Molecular cytogenetic analysis of term placentae suspected of mosaicism using fluorescence in situ hybridization

In first-trimester chorionic villus sampling (CVS) for prenatal diagnosis, abnormal chromosomal findings, such as mosaicism, trisomies, or suspect abnormal karyotypes, are found more frequently than at amniocentesis. The fact that these chromosomal abnormalities do not always reflect the fetal karyotype but may be restricted to the placenta is a major problem in diagnosis and counselling. In this paper we present the results of fluorescence in situ hybridization (FISH) studies on interphase nuclei of three term placentae investigated because of false-positive findings at first-trimester CVS. The chorionic villi of the first case showed a mosaic chromosome pattern involving a trisomy 10 cell line and a normal cell line, those of the second case a total trisomy 8 cell line, while in the third case a complete monosomy X was found. Follow-up amniocentesis in each of these three cases revealed a normal karyotype. By using FISH, we were able to confirm the presence of the aberrant cell lines, which were all confined to one part of the placenta. FISH on interphase nuclei allows the investigation of large numbers of cells for the existence of numerical chromosome aberrations in a quick and reliable way.     

Particle emissions of a railway line determined by detailed single particle analysis

The goal of this study was to identify and quantify particles emitted from railway traffic. For that purpose PM10 samples were collected near a busy railway line using a wind direction and speed controlled sampling equipment consisting of five devices. Measurements taken perpendicular to the railway lines at 10, 36 and 120 m distance enable an identification and separation of particles caused by the railway traffic from background particles. Morphology and chemistry of more than 11,000 particles were analysed by computer controlled scanning electron microscopy (CCSEM). Based on chemical composition five particle classes are defined and assigned to their sources. The mass of the individual particles is determined by multiplying their volumes, calculated based on their morphology with a density assigned specifically to each particle class. The density of the particle classes is derived from their chemical composition. To estimate the PM10 contributions of the railway lines, the mass of PM10 at 120 m (background, not influenced by the railway lines) is subtracted from the mass of PM10 at 10 m. The emissions of the railway lines are dominated by ‘iron’ particles, which contribute 2.9 μg m⁻³ or 67% to the railway related PM10. In addition, ‘aluminium’ and ‘calcium’ particles contribute also to the railway related PM10 (1.0 μg m⁻³ or 23% for the ‘aluminium’ and 0.4 μg m⁻³ or 10% for the ‘calcium’ particles). These particles are assigned to abrasion of the gravel bed and re-suspension of mineral dust.Long-term gravimetric results of the contribution of iron to the mass of railway related PM10 from a study performed earlier at the same site are in good agreement with the data presented in this study.     

Environmental occurrence of Q1, a C9H3C17N2 compound,that has been identified as a natural bioaccumulative organochlorine

Environmental appearance of Q1, a natural heptachloro compound with the molecular formula C₉H₃Cl₇N₂, was studied in samples from different sites all over the world. Q1 was expected to have a bipyrrole backbone, similar to other compounds ascribed to natural sources. A method for isolation of Q1 was developed by combination of adsorption chromatography on silica and normal phase HPLC with an amino phase. UV-detection of Q1 supports the aromatic character of the compound.

The high levels detected in samples of marine mammals and birds suggested that Q1 is both a persistent and a bioaccumulative contaminant. This was underscored by calculated log K_OW in the range of other lipophilic organohalogens. In accordance with earlier studies, highest Q1 concentrations were found in the Southern Hemisphere, but with a highly selective GC/ECNI-MS-SIM method, detection of Q1 was also achieved in many samples from the Northern Hemisphere. In addition to marine mammals and birds, Q1 was also detected in fish from the Mediterranean Sea and the Antarctic. Traces were also detected in SRM 1588 certified cod liver oil, but Q1 was not detected in fish from Hong Kong and Lake Baikal.     

PM10冲击采样器切割头设计参数对切割粒径的影响

本文从颗粒在气流中的受力情况分析入手 ,得到冲击采样器中喷嘴喷出后颗粒的运动轨迹方程以及运动轨迹与采样器切割头设计参数的关系式。分析了PM10空气采样器的切割原理 ,并利用数值计算研究颗粒在不同的流量、喷嘴尺寸及喷嘴与冲击板的距离下的运动轨迹 ,从而得到切割头设计参数对切割粒径的影响     

渭南市区冬春季PM2.5和PM10时间分布特征及与气象因素的关系

为研究渭南市区2014?—?2016年的冬春季雾霾天气的特点,选取覆盖渭南市区的4个监测站点,分析渭南市区PM_(10)和PM_(2.5)污染时间分布特征;同时选取日平均气温、相对湿度、风等气象因素,用线性回归分析法分析各个气象因素同大气中PM_(10)和PM_(2.5)的相互关系。研究发现:三年来冬季PM_(10)和PM_(2.5)的日变化的峰值主要出现在12月—?次年1月;春季PM_(10)和PM_(2.5)的逐日变化的峰值主要出现在3月;日内的周期变化趋势呈多次波动。渭南市区冬春PM_(10)和PM_(2.5)的质量浓度与风速、气温呈负相关,与相对湿度呈正相关,为雾霾的形成创造了条件,在冬季温度较高的情况下以及相对湿度较大的情况下应加强防范。在冬季12月—?次年1月和春季3月应注意雾霾的防范和治理,燃煤企业要安装脱硫脱硝装置,居民日常生活中尽量减少生物燃料的燃烧,同时政府应根据污染物排放量征税,用制度保护环境。     

基于机器学习和卫星遥感的PM2.5/10 空间连续分布反演方法研究

在过去的几十年里,快速的经济发展以及工业化、城镇化进程加速使得中国的资源环境承担的压力不断加大。作为影响空气质量的首要污染物,PM_2.5和PM₁₀（记为PM_2.5/10）直接影响着广大人民群众的身体健康。因此,针对PM_2.5/10浓度进行遥感反演研究,对环境监测和控制改善全国空气环境质量具有重要的意义。近些年来,随着对近地面PM_2.5/10浓度研究的不断深入,基于遥感影像数据进行PM_2.5/10浓度的反演方法也日益增多。本文利用Google Earth engine（GEE）平台获取了海量的Landsat 8 OLI遥感影像数据,并结合气象信息、空间特征等参数,采用机器学习中常用的多层映射反向传播神经网络构建了波段反射率与PM_2.5/10浓度之间的反演模型,以获得PM_2.5/10在研究区域的连续分布。为了提高基础PM_2.5/10反演模型的反演精度,还从影响因素和前溯时间两个维度出发,探寻了模型的最优化输入参数组合,并最终实现了对PM_2.5/10浓度的精准反演。以北京市地区为例,模型的PM_2.5和PM₁₀的反演精度R²分别达到0.814和0.796,均方根误差RMSE分别为19.21 μg?m^?3和28.31 μg?m^?3。鉴于该反演结果具有较高的准确性和可靠性,本文所建立的方法模型为研究PM_2.5/10在空间上的连续分布特征提供了新的思路和方法,具有较为重要的科研意义与广泛的应用价值。     

植物叶表尘及重金属对城市大气颗粒物污染的指示与评估

城市大气颗粒物污染问题日渐突出,目前主要依靠大气站点的直接观测数据反映污染的即时状况,而植物叶表尘及重金属的监测为评价大气颗粒物阶段性污染状况提供了新的途径.本研究通过分析北京交通带和公园共7个样点的臭椿(Ailanthus altissima)、槐(Sophora japonica)、北京杨(Populus beijingensis)、榆树(Ulmus pumila)、紫叶李(Prunus cerasifera f.atropurpurea)等5种常见绿化树种的叶表尘及重金属Cd、Cr、Cu、Mn、Ni、Pb、Zn含量,并计算尘金属综合累积指数(MAI),进而与邻近站点大气颗粒物观测数据对比并进行统计分析,尝试量化评价植物所处环境的大气颗粒物及尘重金属综合污染状况.结果表明:采用榆树叶表尘可量化评价大气可吸入颗粒物PM10的月均质量浓度,相对误差为1.2%~10.6%;臭椿叶表尘可量化评价大气细颗粒物PM2.5的月均质量浓度和月均空气质量指数(AQI),相对误差分别为0.18%~3.7%和0.26%~5.7%.MAI值可指示大气尘重金属综合污染状况,本研究中京承高速和朝阳公园大气尘重金属综合污染较重,其次为念坛公园、望京公园和玉蜓桥,最轻为岳各庄桥和麋鹿苑.     

A bioaugmentation failure caused by phage infection and weak biofilm formation ability

Two biological aerated filters (BAF) were setup for ammonia removal treatment of the circulation water in a marine aquaculture. One of the BAFs was bioaugmented with a heterotrophic nitrifying bacterium, Lutimonas sp. H10, where the ammonia removal was not improved and the massive inoculation was even followed by a nitrification breakdown from day 9 to 18. The nitrification was remained stable in control BAF operated under the same conditions. Fluorescent in situ hybridization (FISH) with rRNA-targeted probes and cultivable method revealed that Lutimonas sp. H10 almost disappeared from the bioaugomented BAF within 3 d, and this was mainly due to the infection of a specific phage as revealed by flask experiment, plaque assay and transmission electron observation. Analyses of 16S rRNA gene libraries showed that bacterial groups from two reactors evolved di erently and an overgrowth of protozoa was observed in the bioaugmented BAF. Therefore, phage infection and poor biofilm forming ability of the inoculated strain are the main reasons for bioaugmentation failure. In addition, grazing by protozoa of the bacteria might be the reason for the nitrification breakdown in bioaugmented BAF during day 9–18.     

上海吴淞地区PM_(10)中重金属的来源分析

使用8通道采样器ACCU(Automatic Cartridge Collection Unit)对上海吴淞地区进行大气颗粒物PM10的采样。对滤膜采用质子激发X射线荧光(PIXE)分析方法进行重金属质量浓度测定,然后对获取的数据分别进行主成分分析,讨论了吴淞地区PM10中含有的主要重金属的可能来源。     

武汉市PM_(10)源解析及其对策研究

随着我国社会经济的迅速发展,大气环境中颗粒物的污染日趋突出,PM10是当今最受关注的空气污染物之一,文章在为期13个月监测的基础上,对武汉市大气中PM10的污染水平、元素组成及其来源与贡献进行了研究,并针对PM10中不同组分的来源提出了控制措施。