A case of partial sirenomelia and possible vitamin A teratogenesis

Prenatal echographical findings of a partial sirenomelic fetus are described. An attempt was made to terminate pregnancy by administration of prostaglandin F₂a, but uterine rupture occurred. The teratogenic role of vitamin A ingested by the mother in the penconceptional period is discussed.     

胶州湾大沽河口邻近海域海水水质预测

通过对胶州湾水质现状的数值模拟 ,预测了胶州市城市污水处理场建成后 ,在正常运行和事故情况下大沽河口邻近海域的水质。预测结果表明 :在污水处理场正常运行情况下 ,除大沽河入海口很小面积范围内超二类海水水质标准 ,邻近其他海域皆不超二类海水水质标准 (GB 30 97 1997) ,但在事故情况下 ,大沽河邻近海域超二类海水水质标准的面积较大 ,且有超四类海水水质标准的区域。因此 ,要确保大沽河口邻近海域水质的改善 ,污水处理场的正常运行是关键。     

First-trimester biochemical and molecular diagnoses using chorionic villi: High accuracy in the U.S. collaborative study

The accuracy of biochemical and molecular prenatal diagnoses using chorionic villi as the fetal source was assessed by seven centres participating in the NICHD collaborative study on the safety and accuracy of chorionic villus sampling (CVS) and amniocentesis. Of 601 pregnancies studied, biochemical methods were used to determine the diagnosis in 283 fetuses at risk for 35 different metabolic disorders. Fifteen different lysosomal storage diseases accounted for 81 per cent of the biochemical prenatal diagnoses performed, with 57 per cent of these pregnancies at risk for Tay-Sachs disease. No errors were made in the biochemical diagnoses that predicted affected or unaffected fetuses. However, the diagnoses of certain disorders (e.g., mucopolysacchariodosis type IH, metachromatic leukodystrophy, and Krabbe disease) occasionally required confirmatory studies in cultured amniocytes because the enzyme results were inconclusive in direct and/or cultured villi or due to the presence of a pseudodeficiency allele. Of these, only the diagnosis of a fetus at risk for Krabbe disease remained inconclusive after special studies to discriminate between mutant and pseudodeficiency alleles. Recombinant DNA techniques were used to predict the diagnosis of 318 fetuses at risk for 16 different disorders in which the defective disease gene could be detected either directly or by linkage analysis to a nearby polymorphic marker. Of these, 32 per cent were for haemoglobinopathies, 25 per cent for cystic fibrosis, 24 per cent for Duchenne or Becker muscular dystrophy, and 7 per cent for haemophilias. Pregnancies at risk for known disorders with specific molecular lesions (e.g., sickle cell disease) were accurately diagnosed in direct and/or cultured villi. Diagnoses requiring analyses with closely linked polymorphic markers were occasionally uninformative or inconclusive. Maternal contamination was not reported in any biochemical or molecular-based diagnosis. These studies document the high accuracy and rapidity of both biochemical and mutation-specific prenatal diagnoses with direct and cultured chorionic villi.     

利用造纸废物生产全粉煤灰轻质建筑材料研究(Ⅰ)

根据外营力自然成岩理论 ,探讨了利用造纸废物与粉煤灰生产复合材料的新理论、新工艺。在工业性试生产中产生的制品具有容重轻、强度高 ,隔热性能和憎水性良好的优点 ;同时 ,由于其吃灰量大 ( >95 % ) ,又为大规模利用粉煤灰开辟了新途径。     

海洋环境下航空电连接器腐蚀行为规律研究

目的研究电子设备中电连接器的腐蚀问题。方法以军用飞机典型电连接器为研究对象,在实验室条件下模拟军用飞机服役的海洋环境条件,开展加速腐蚀试验。得到电连接器宏观、微观腐蚀形貌,接触电阻和绝缘电阻的变化规律,分析加载电流和未加载电流对电连接器腐蚀行为的影响规律。结果在腐蚀试验的前3个周期,绝缘电阻值在1500～0 M?之间剧烈变化,到第4个周期降到0 M?,完全丧失绝缘性能。结论加载电流明显加重了电连接器的腐蚀程度,导致接触电阻快速增大,腐蚀明显劣化了电连接器的导电性能。     

上海气象参数与太阳活动和ENSO的关系

运用2进小波的分解与重构技术分析了太阳活动、厄尔尼诺—南方涛动(ENS0)与上海地区月降水量、月均气压和月均温度序列之间的可能关系。研究结果表明，在不同的时间尺度(频带)上太阳活动和ENS0对上海的月降水量、月均气压和月均温度有不同的影响；在某种程度上ENS0活动对上海月降水量和月均气温的影响强于太阳活动的影响。结果还清楚表明和证实了在不同频带上太阳活动与ENS0活动之间的密切联系。     

正确引导有机食品产业的发展

论述了有机食品开发中存在的问题，提出了发展有机食品产业的建议。     

Decline of sacred fir (Abies religiosa) in a forest park south of Mexico City

Decline of sacred fir (Abies religiosa) trees in the high elevation forest park, Desierto de los Leones, located south of Mexico City, is described. Trees located in the windward zone (exposed to air masses from Mexico City) were the most severely affected, especially trees at the distal ends of ravines. Examination of tree growth rings indicated decreases in ring widths for the past 30 years. Polluted air from Mexico City may be an important causal factor in fir decline. Drought, due to excessive removal of soil water, insects, mites and pathogens, and poor forest management are possible contributing and interactive factors in fir decline.     

Effects of early developmental conditions on innate immunity are only evident under favourable adult conditions in zebra finches

Long-term effects of unfavourable conditions during development can be expected to depend on the quality of the environment experienced by the same individuals during adulthood. Yet, in the majority of studies, long-term effects of early developmental conditions have been assessed under favourable adult conditions only. The immune system might be particularly vulnerable to early environmental conditions as its development, maintenance and use are thought to be energetically costly. Here, we studied the interactive effects of favourable and unfavourable conditions during nestling and adult stages on innate immunity (lysis and agglutination scores) of captive male and female zebra finches (Taeniopygia guttata). Nestling environmental conditions were manipulated by a brood size experiment, while a foraging cost treatment was imposed on the same individuals during adulthood. This combined treatment showed that innate immunity of adult zebra finches is affected by their early developmental conditions and varies between both sexes. Lysis scores, but not agglutination scores, were higher in individuals raised in small broods and in males. However, these effects were only present in birds that experienced low foraging costs. This study shows that the quality of the adult environment may shape the long-term consequences of early developmental conditions on innate immunity, as long-term effects of nestling environment were only evident under favourable adult conditions.