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761.
762.
A simple high resolution technique for human chromosomes is described for fibroblasts obtained from amniotic fluid cell cultures. The application and clinical significance of this technique in prenatal diagnosis is discussed. 相似文献
763.
In 450 patients with pregnancy at high risk for fetal malformation and/or intrauterine growth retardation, the umbilical cord was investigated sonographically for the presence of a single umbilical artery. A single umbilical artery was diagnosed in four fetuses between 23 and 33 weeks of gestation and suspected in two. Three cases were overlooked at sonography. All seven surviving fetuses had growth retardation at delivery and four also showed severe malformations. Whenever a single umbilical artery is found at sonography, further work-up is required to rule out associated anomalies, intrauterine growth retardation, or chromosomal abnormality. 相似文献
764.
A survey was conducted on 15th November, 1970, in mangrove forests and backwater regions of a section of the Vellar-Coleroon estuarine complex; a total of 19 stations were occupied. Detailed investigations on nutrients, pigments, and plankton were carried out. The following ranges in values were recorded: salinity, 10.40 to 30.50; pH, 7.50 to 8.30; temperature, 29.50° to 30.50°C; total phosphorus, 0.72 to 3.34 g at/l; inorganic phosphate, 0.19 to 1.59 g at/l; ammonia, 0.34 to 0.36 g at/l; nitrite, 0.11 to 0.25 g at/l; nitrate, 2.85 to 6.94 g at/l; silicate, 18.49 to 134.92 g at/l. Dissolved oxygen content ranged from a minimum of 3.69 ml to a maximum of 5.44 ml/l. Chlorophyll a ranged from an undetectable amount to 1.01 mg/m3, chlorophyll b from 0.02 to 0.85 mg/m3, chlorophyll c from 0 to 0.41 mg/m3 and carotenoids from 0 to 0.74 MSPU/m3. The plankton displacement volume ranged from a negligible amount to 3.60 cm3/m3; seston varied between 0.29 and 0.91 g/l. Phytoplankton was abundant at 3 stations; at other stations zooplankton was abundant. Coscinodiscus, Asterionella and Ditylum were the dominant forms among the phytoplankton; Oithona, Acrocaanus, Euterpina, Centropages, Corycaeus, Lucifer and Oikocreura were dominant among the zooplankton. Phytoplankton and zooplankton populations, as percentage of the total plankton, varied between 3.70 and 89.00% and between 11 and 96.30%, respectively. Average gross production values in the mangrove and back-water stations were 7.56 and 3.33 g C/m3/day, and the net production values 6.29 and 2.67 g C/m3/day, respectively. 相似文献
765.
Maximum substrate and cosubstrate affinity, as judged by the Michaelis constant (K
M
), of NADP+-dependent isocitrate dehydrogenase of pig heart (purchased from Boehringer, Mannheim, FRG) is attained at 37°C. If K
M
-values of substrate (Isocitrate, IC) and cosubstrate (NADP+) of NADP+-dependent isocitrate dehydrogenase (ICDH) of the white dorsal muscle of Idus idus L. is plotted against the experimental temperature (VT), W-shaped curves result. With increasing adaptation temperature (AT), there is a shift to increasing VT. It is suggested that the W-shaped curves are due either to the simultaneous presence of two multiple forms of the enzyme, or to the reversible temperature-dependent interconversion of one protein species. 相似文献
766.
Dr G. Petsch 《Environmental geochemistry and health》1982,4(2-3):75-80
In 1979 it was noted that the production of deep-mined coal in the Federal Republic of Germany, including the Ruhr area, has risen once again. Since the beginning of the sixties the convenient source of both energy and raw material, oil, has been responsible for the falling levels of coal production in the Ruhr, to almost one half of peak production in 1956. Not much would have been needed to give up the entire troublesome and expensive process of deep coal mining in the Federal Republic in favour of the then cheap and bountiful oil. Only lignite managed to maintain a more or less steady annual production rate due to the direct conversion into electricity of a major part of its production at the site of extraction. Since the limitations and uncertainties governing the supply of crude oil have now been clearly exposed, the illusions about oil have begun to fade, and as a result confidence in our indigenous supplies of energy and raw material resources has been restored. What, however, are the implications of this revival of home-produced energy and raw material, which are not without problems both when produced and when consumed for the region in which they are extracted and brought to the surface, and where, to a large extent, the processing takes place? The region benefits from employment and investment, and in turn offers its resources (labour, land, water, air) inasmuch as past development has left them available for future development. But is the region to be covered with even more ‘honourable’ scars? In 1980, 87 million tonnes of deep mined coal were produced in the Federal Republic of Germany which resulted in roughly the same amount of minestone (spoil). Approximately 600 km2 of densely populated area in the Ruhr district was already acquiring artificial drainage due to subsidence. Coking plants and old coal-based stations fired with deep mined coal pollute air and water. Lignite production in 1980 in the Federal Republic of Germany — which was almost entirely obtained by opencast mining — amounted to 130 million tonnes. To achieve this an additional 445×106m3 of overburden had to be shifted. Already in 1977 in the Rhineland between Cologne, Dusseldorf and Aachen (Aix-la-Chapelle), 522 km2 of mainly good agricultural land was acquired under compulsory purchase order for lignite mining. Villages, roads, rail and waterways were and continue to be re-routed and re-sited. The direct conversion of lignite into electricity produces emission and spreads pollution. Now, it is not only the people of the Ruhr area, the largest industrial conurbation in Europe, that have become sensitive to the impact of mining upon their environment. In all industrial countries it has been learned that those things which cannot be replaced, i.e. environment, are not always being valued by the free market at a price which represents the value they may have for the individual and possibly should have for all of us. Today the need for mining is hardly being questioned any more but people are voicing their opinion as to what is a just price to be paid. The citizen of the Ruhr, for instance, no longer accepts that the specific environmental impacts caused by deep coal mining, which produces a commodity wanted by the entire nation, should be borne solely at the place where it is produced and by the people who happen to live there. He demands that such burdens are borne by everybody who enjoys the benefits. Clear political ideas must be developed and made know as to how much we value home-produced energy sources, what proportion of the resulting burdens the country is willing to bear and how they are to be distributed fairly. There are many methods and technical means by which the burdens of the mining and industrial regions can be minimised, by which damage can be repaired and derelict areas reclaimed. The application of such means must be safeguarded by early planning and sufficient finanacing so that the exploitation of one resource will not result in other resources being lost. 相似文献
767.
768.
769.
770.
Dr. P. P. Ewald 《Die Naturwissenschaften》1914,2(10):217-222