Amniotic fluid alpha-fetoprotein,gamma-glutamyltranspeptidase,and autosomal trisomies

Alpha-fetoprotein (AFP) concentration and gamma-glutamyltranspeptidase (GGT) activity have been analysed in amniotic fluid from a series of 65 pregnancies with autosomal trisomies. AFP values were reduced on average to 60 per cent of normal in cases of trisomy 21, but were not significantly different from normal in cases of trisomies 18 and 13. GGT activities were uniformly lower (44 per cent of normal) for all types of autosomal trisomy. A review of the literature indicates that over 85 per cent of Down's pregnancies but only 39 per cent of trisomy 18 and 13 pregnancies have amniotic fluid AFP levels below the normal median value, while the corresponding figures for GGT are 91 per cent for Down's syndrome and 96 per cent for trisomies 18 and 13.     

Quantenchaos: Komplexe Dynamik im Grenzbereich zwischen mikroskopischer und makroskopischer Physik

Die Autoren danken der Deutschen Forschungsgemeinschaft für die Förderung dieser Arbeit im Sonderforschungsbereich 237 Unordnung und große Fluktuationen. T. Dittrich dankt der Abteilung für Kernphysik am Weizmann Institut, Rehovot, Israel, insbesondere Prof. U. Smilansky, für Gastfreundschaft während der Fertigstellung des Manuskripts.     

Field and experimental studies on cadmium in the edible crab Cancer pagurus

The distribution of cadmium within captive crabs (Cancer pagurus) exposed experimentally to cadmium-contaminated food and water is described and illustrated by triangular diagrams. Crabs from the Orkney Islands (Scotland) are known to contain relatively high levels of cadmium (up to 62 g g^-1 wet wt) in the hepatopancreas. The distribution of cadmium between the hepatopancreas, gonad, gill, carapace, claw muscle, heart, and haemolymph, is described in crabs collected during 1978, and compared with similar data from crabs exposed to cadmium for ca. 300 d (September 1978 – June 1979) experimentally. It is concluded that the dominant uptake route of cadmium to Orkney crabs is through their diet.     

Triploidy: Pregnancy complications and clinical findings in seven cases

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth–Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.     

瑞典水文变化-气候变化影响模拟

温室效应加剧导致的气候变化将会引起水文系统的变化.随着气候要素的变化,水文变化将会在全球呈现出区域差异性.因此,有必要开展局地和区域尺度上的水文变化影响研究,评价不同区域将会受到怎样的影响.本研究旨在对广泛的瑞典流域上气候变化的水文影响(响应)进行评估.我们采用不同的方法,将气候模型中产生的气候变化信号转换输入到水文模型中.利用瑞典区域气候模拟计划(SWECLIM)生成的区域气候情景,我们进行了几次水文模型模拟研究.得出的基本结论是根据流域的地理位置处于瑞典北部或南部,气候变化对河道水流的分区影响是显著不同的.此外,预测的水文变化不仅与用于确定区域气候模型边界条件的全球气候模型的选择有关,而且与人为气体排放情景的选取有关.     

Sorption of ozone by 'New Yorker' tomato leaves

Tomato (Lycopersicon esculentum Mill.) 'New Yorker' plants were exposed to O(3) to compare leaf diffusive conductance (LDC) before exposure to O(3) with O(3) sorption rates and visible injury ratings. Two plant development stages and four or five leaf growth stages were examined. The LDC varied among leaf growth stages and between plant development stages and leaf surfaces; there was no continuity in the LDC pattern. Sorption rates differed among some leaf growth stages, and between plant development stages in expanding leaves (growth stage 1). For both development stages high sorption rates occurred in fully mature leaves; otherwise little similarity between corresponding leaf growth stages was evident. Total O(3) flux to the leaf was not well predicted by the LDC for water vapour; nor was visible injury well related to total flux. Differential mesophyll processes and leaf surface sorption capabilities may have accounted for some of the inconsistencies observed.     

Flooding and the Distribution of Selected Metals in Floodplain Sediments in St. Maries, Idaho

The link between sediment contamination and flooding is not well established, since flooding may exacerbate problems by spreading pollutants throughout the floodplain, or alternatively may dilute contaminants in source areas. To determine the substance of such relationships, the pattern of sediment contamination was examined in a small Idaho town following flooding in 1996. Four heavy metals were tested, nickel, chromium, zinc and copper, in 97 soil samples obtained from sites across the floodplain of the St. Joe River. Flood history and land-uses at each sample site were noted. Results showed that contamination levels generally were not high, with flood areas having lower concentrations than non-flood areas. A stronger relationship could be argued for land-use, with higher concentrations of contamination associated with some industrial sites. High levels of contamination were also found in several samples taken from recreational areas. Further research looking at the potential sources of contamination in relation to characteristics of the flood hydrology would seem pertinent.     

气候变化对波罗的海入海河流流量的影响

进入波罗的海的河流流量是在一个面积约160万km2的流域中各种不同气候状况下产生的.波罗的海流域气候的变化不仅影响入海淡水的总量,而且对这些水源的分配亦有影响.利用水文模拟,分析了未来气候变化对波罗的海入海径流的影响.使用了瑞典区域气候模拟计划(SWECLIM)中的4种不同的气候变化情景.根据这些不同的气候情景,全部入海河流总的平均年入海量的变化范围为当前入海量的-2%～+15%.波罗的海不同亚区的入海量的变化是大不相同的,其中最剧烈的年均变化范围是-30%～+40%.但是,所有评价的气候情景的共同点是总体趋势为来自波罗的海流域南部地区入海流量减少,北部地区入海量增加.     

Characterization of Fugitive Material within a Primary Lead Smelter

ABSTRACT

The primary production of Pb via the sinter plant-blast furnace method resulted in a large number of Pb and other phases, reflecting the complex reactions occurring within each of the processes. Optical microscopy and X-ray diffraction (XRD) techniques have been used to characterize fugitive emissions and dusts generated during sintering, smelting, Cu drossing, refining, and slag fuming at a primary Pb-Zn smelter. The results displayed a complex array of phases, with the mineralogy of the dusts and fume reflecting conditions of the particular metallurgical operation. The principal Pb species followed a transformation from PbS through PbSO₄ and PbO to Pb° (metal) from raw materials to the refinery. The fugitive emissions generated by the blast furnace were of a finer size with more complex chemistry than fugitive material from other source areas. XRD identified a mixture of PbS, ZnO, and ZnS, associated with one or more of the Cl-bearing phases Pb(OH)Cl, PbCl₂, Pb₄O₃Cl₂, Na₃Pb₂(SO₄)₃Cl, Pb₁₀(SO₄)Cl₂O₈, Pb₄SCl₆, and Pb₇S₂Cl₁₀. The presence of Cl-bearing phases in the fume has possible health implications.