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81.
The conclusions are put forward that are adopted by a discussion group preparing the framework for a limitation policy of the radon problem in Belgium. Existing and future situations are treated in a coherent policy that is adequate for practical implementation. An action level is defined, together with a hierachy of levels for new constructions. The decision logic for the acceptance of building materials is explained. 相似文献
82.
J. Buytaert L. De Boeck F. Verbeure
C. Bricman
F. Cao C. De Clercq L. Etienne B. Goorens J. Lemonne F. Stichelbaut S. Tavernier G. Van Beek C. Vander Velde W. Van Doninck L. Van Lancker J. WickensE. Daubie
F. Defontaines F. Grard J. Kesteman O. Pingot C. Poiret 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1991,310(3):596-606The layout and construction of the muon drift chambers equipping the end caps of the DELPHI detector are described. The performance of this forward muon detection system, determined from cosmic ray tests and data collected during the first year of LEP operation, is presented. 相似文献
83.
J G De Nobel F M Klis A Ram H Van Unen J Priem T Munnik H Van Den Ende 《Yeast (Chichester, England)》1991,7(6):589-598
To study cell-cycle-related variations in wall permeability of Saccharomyces cerevisiae, two approaches were used. First, an asynchronous culture was fractionated by centrifugal elutriation into subpopulations containing cells of increasing size. The subpopulations represented different stages of the cell cycle as judged by light microscopy. Cell wall porosity increased when these subpopulations became enriched with budded cells. Secondly, synchronous cultures were obtained by releasing MATa cells from alpha-factor induced G1-arrest. These cultures grew synchronously for at least two generations. The cell wall porosity increased sharply in these cultures, shortly before buds became visible and was maximal during the initial stages of bud growth. It decreased in cells which had completed nuclear migration and before abscission of the bud had occurred. The porosity reached its lowest value during abscission and in unbudded cells. We examined the incorporation of mannoproteins into the wall during the cell cycle. SDS-extractable mannoproteins were incorporated continuously. However, the incorporation of glucanase-extractable mannoproteins, which are known to affect cell wall porosity, showed cyclic oscillations and reached its maximum after nuclear migration. This coincided with a rapid decrease in cell wall porosity, indicating that glucanase-extractable mannoproteins might contribute to this decrease. 相似文献
84.
85.
分子筛吸附柱和热金属镁床是手套箱气氛中氚化水 (HTO)搜集和分解处理的一种有效手段。测试了分子筛柱对气氛中水的吸附性能和热金属镁床对HTO的分解性能。结果表明 :分子筛柱对气氛中水的吸附效率 >99 99% ,在空气中水含量为 3 4× 1 0 - 3~ 4 2× 1 0 - 3条件下 ,未发现吸附柱水的贯穿现象 ;热金属镁床对HTO的分解率 >99 9% ,当金属镁的消耗量大于 80 %时 ,未见分解率明显降低。 相似文献
86.
P. R. J. M. Smits P. H. Van Lieshout A. A. F. Van De Ven 《Journal of Engineering Mathematics》1989,23(2):157-186
A variational principle for the magnetoelastic stability problem of superconductors is constructed. Independently, a pair of integral equations is derived, from which the initial and the perturbed field can be computed. The integral equations are solved for in-plane buckling of a slender pair of concentric tori, and out-of-plane buckling of a slender pair of equal coaxial tori. By using the variational principle, it is shown that both cases can become unstable when the currents on the two tori are equally directed, and the pertinent buckling values are calculated. The thus obtained buckling values are compared with the results of an alternative, mathematically less rigorous, method. A good correspondence between the two methods is found (at least as long as the two tori are not too near). 相似文献
87.
88.
P Pirazzoli E Cacciari R De Iasio MC Pittalis P Dallacasa S Zucchini S Gualandi S Salardi C David S Boschi 《Canadian Metallurgical Quarterly》1997,77(2):F100-F104
AIMS: To evaluate the developmental pattern of fetal growth hormone (GH), insulin-like growth factor I (IGF-I), GH binding protein (GHBP) and IGF binding protein-3 (IGF-3); to determine the implications for fetal growth. METHODS: Serum GH, IGF-I, GHBP and IGFBP-3 were measured in 53 fetuses, 41 aged 20-26 weeks (group A) and 12 aged 31-38 weeks (group B). Fetal blood samples were obtained by direct puncture of the umbilical vein in utero. Fetal blood samples were taken to rule out beta thalassaemia, chromosome alterations, mother to fetus transmissible infections, and for maternal rhesus factor. GHBP was determined by gel filtration chromatography of serum incubated overnight with 125I-GH. GH, IGF-I and IGFBP-3 were determined by radioimmunoassay. RESULTS: Fetal serum GH concentrations in group A (median 29 micrograms/l, range 11-92) were significantly higher (P < 0.01) than those of group B (median 16.7 micrograms/l, range 4.5-29). IGF-I in group A (median 20 micrograms/l, range 4.1-53.3) was significantly lower (P < 0.01) than in group B (median 75.2 micrograms/l, range 27.8-122.3). Similarly, IGFBP-3 concentrations in group A (median 950 micrograms/l, range 580-1260) were significantly lower than those of group B (median 1920 micrograms/l, range 1070-1770). There was no significant difference between GHBP values in group A (median 8.6%, range 6.6-12.6) and group B (median 8.3%, range 6-14.3). Gestational age correlated positively with IGF-I concentrations (P < 0.0001) and IGFBP-3 (P < 0.0001) and negatively with GH (P < 0.0001). GHBP values did not correlate with gestational age. Multiple regression analysis showed a negative correlation between GH:IGF-I ratio and fetal growth indices CONCLUSIONS: The simultaneous evaluation of fetal GH, IGF-I, IGFBP-3 and GHBP suggests that the GH-IGF-I axis might already be functional in utero. The progressive improvement in the efficiency of this axis in the last part of gestation does not seem to be due to an increase in GH receptors. 相似文献
89.
S Manfredini D Simoni R Ferroni R Bazzanini S Vertuani S Hatse J Balzarini E De Clercq 《Canadian Metallurgical Quarterly》1997,40(23):3851-3857
In a dual targeting approach, to explore the ability of tretinoin (all-trans-retinoic acid) to behave as a covalent carrier for cytotoxic entities, conjugates of retinoic acid with a few representative molecules, being important examples of antitumor pharmacophores (i.e., nucleoside analogues and alkylating agents), have been synthesized and tested for their cytostatic and differentiating activity. All compounds were stable to in vitro hydrolysis in human plasma and more lipophilic than the parent compounds, thus consenting enhanced uptake into the cells. Among the nucleoside analogues the Ara-C derivatives 3 and 6 and the Ara-A derivative 7 proved the most cytostatic (IC50 < 0.32 microgram/mL) resulting from 25- to > 144-fold more active (Ara-A derivatives) or at least as equally active (Ara-C derivatives) as compared to the parent nucleosides. Compound 3, endowed with a highly lipophilic silyl moiety at the 3' and 5' positions, showed the highest differentiating activity (54% and 44% differentiated HL-60 cells at 0.2 and 0.05 microgram/mL respectively). With regard to the retinoic acid conjugates of alkylating agents, compound 10 was the most cytostatic agent (IC50 < 0.32 microgram/mL) and the most potent differentiating agent (33-34% at 0.32 and 0.08 microgram/mL). These structures may also be regarded as analogs of either retinoic acid or the cytotoxic compound. 相似文献
90.
P Casolo D Mosca C Amorotti B Drei A Raspadori P Di Blasio E Ganz G De Luca G Colli R De Maria D Amuso 《Canadian Metallurgical Quarterly》1997,68(2):207-11; discussion 212
Primary and sole breast lymphoma is a very rare disease. With the review of our series of 616 cases operated on for breast cancer, only 3 cases (0.48%) of primary breast non-Hodgkin lymphoma (LNH) have been observed. The authors outline the problems concerning diagnosis and therapy of this rare disease: pathological and immunohistochemical aspects are discussed. They stress the importance of staging in order to plan a correct multidisciplinary approach. 相似文献