彩钢行业VOCs排放特征及O3和SOA生成潜势

采用固相吸附-热脱附-气质联用技术对浙江某市典型彩钢企业生产车间与废气处理装置进行了VOCs定量分析,获得了该行业的特征VOCs成分谱,并利用最大反应增量法（MIR）和气溶胶转化系数法（FAC）估算了彩钢行业各组分VOCs对臭氧（O₃）及二次有机气溶胶（SOA）的生成潜势.结果显示：该市彩钢行业VOCs成分复杂,酯类和醇类占比在50%以上;车间VOCs浓度水平受温度影响大,夏季浓度约为冬季浓度的1.6~4.2倍;通过对O3和SOA的计算可知,芳烃类、醇类物质对O₃生成潜势贡献率分别为70.0%和28.05%,而SOA生成潜势完全由芳烃类物质提供.     

Risk assessment of amniocentesis between 11 and 15 weeks: Comparison to later amniocentesis controls

We studied 693 consecutive early amniocenteses (prior to 15 weeks) and found a spontaneous abortion rate to 28 weeks' gestation of 1·5 per cent. A control group of women having standard amniocentesis (15–20 weeks) experienced a 0·6 per cent fetal loss in the same period. There were no other apparent differences between the two groups. Early amniocentesis results are generally available 4–6 weeks before standard amniocentesis and 1–3 weeks after chorionic villus sampling (CVS). Alpha-fetoprotein (AFP) can be accurately assayed in 11- to 15-week amniotic fluid samples but additional studies are necessary to determine the accuracy of neural tube defect (NTD) detection. Including the present study, over 5800 early amniocenteses have been reported and the results suggest that this is a relatively safe prenatal diagnostic test and an alternative to CVS and later amniocentesis.     

Normal second-trimester amniotic fluid alphafetoprotein and acetylcholinesterase associated with fetal sacrococcygeal teratoma

Amniocentesis was performed at 19 weeks' gestation on a patient with two sequential serum alphafetoprotein values above 2 times median. Ultrasound examination suggested a possible sacrococcygeal teratoma. However, both amniotic fluid alphafetoprotein and acetylchol-inesterase were normal, and the patient elected to continue her pregnancy. At 24 weeks fetal demise was confirmed, and prostaglandin induction of labour produced a macerated female fetus with a large sacrococcygeal teratoma.     

芜湖市大气挥发性有机物污染特征、大气反应活性及源解析

2018年9月至2019年8月对芜湖市城区大气中挥发性有机物（VOCs）进行观测,探讨其污染特征、光化学影响和来源.结果表明,芜湖市大气中VOCs全年平均体积分数为27.86×10^-9,季节变化规律为：秋季（31.16×10^-9） > 夏季（28.70×10^-9） > 冬季（24.75×10^-9） > 春季（24.04×10^-9）,日变化规律呈双峰型,峰值在08：00~09：00时与18：00~19：00时出现,与交通流量的变化有关.芜湖市大气VOCs的平均臭氧生成潜势（OFP）为255.29 μg ·m^-3,不同组分对平均OFP的贡献率排序为：芳香烃（48.83%） > 烷烃（21.04%） > 烯烃（18.32%） > OVOCs（11.47%） > 卤代烃（0.35%）.总气溶胶生成潜势（AFP）为1.84 μg ·m^-3,芳香烃贡献率最高（87.69%）,其次为烷烃（12.31%）.苯/甲苯/乙苯（B/T/E）比值表明,芜湖市大气中苯系物的主要贡献源为机动车排放源和工业排放及溶剂使用源.源解析显示：油气挥发源、机动车排放源、溶剂挥发源、LPG排放源、植物排放源和二次生成源对采样期内的VOCs贡献率分别为11.57%、34.53%、16.63%、20.76%、3.54%和12.97%.     

Prenatal ascertainment of triploidy by maternal serum alpha-fetoprotein screening

We report our experience in ascertaining fetal triploidy during routine maternal serum alpha-fetoprotein (MSAFP) screening. Three cases were identified after elevated MSAFP tests. Two of the three had normal amniotic fluid alpha-fetoprotein (AFAFP). The third had amniocentesis too late for AFAFP interpretation. Three additional cases were detected by amniocentesis without prior MSAFP screening and none had an elevated AFAFP. A literature review revealed eight triploid fetuses detected as a result of an elevated MSAFP. Of the five with AFAFP quantitation, only one had an abnormal value and the elevation was minimal. In these 14 cases from our own and other reports, ultrasound findings of placental and fetal abnormalities were often noted, but a pattern diagnostic of triploidy was not present. We conclude that, for optimal prenatal detection of triploidy, fetal karyotyping should be included when an amniocentesis is performed for elevated MSAFP.