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1.
Purified cell-envelope polyphosphatase as well as polyphoshatase activities of cytosol and isolated vacuoles, of nuclei and mitochondria of the yeast Saccharomyces cerevisiae were compared. The polyphosphatases of cell envelope and cytosol are similar, the polyphosphatases of nuclei, vacuoles and mitochondria differ in their kinetic properties, substrate specificity, requirements in divalent cations and in some effector actions both from these and from each other. 相似文献
2.
Increased concentrations of octachlorodibenzo-p-dioxin in cases with breast cancer--results from a case-control study 总被引:1,自引:0,他引:1
L Hardell G Lindstr?m G Liljegren P Dahl A Magnuson 《Canadian Metallurgical Quarterly》1996,5(5):351-357
Organochlorines are persistent and highly lipophilic environmental contaminants which bioaccumulate in the food chain. Some of these chemicals, 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), have been suggested to be of significance in the aetiology of breast cancer. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an anti-oestrogen in animal studies and should be thus lower the risk of breast cancer. The other isomers of polychlorinated dibenzo-p-dioxins (PCDDs) or the chemically related polychlorinated dibenzofurans (PCDFs) have not been tested regarding carcinogenesis of the breast. The purpose of this study was to investigate whether PCDDs or PCDFs influence the risk for breast cancer. Consecutive patients who underwent surgery for a breast disease between 1993 and 1995 were recruited for the study. Cases were 22 patients with infiltrative breast cancer and controls were 19 patients operated for a benign breast disease during the same time period. Approximately 10 g of breast tissue free from tumour was taken from the specimen and frozen until analysis. Fat was extracted, cleaned and analysed with a high-resolution gas chromatograph coupled to a high-resolution mass spectrometer. Median concentrations of octachlorinated dibenzo-p-dioxin (OCDD) were 598 (170-14,880) and 396 (103-1,847) pg/g lipid in the cases and in the controls, respectively. In a multivariate logistic regression analysis controlling for other risk factors for breast cancer increased odds ratio (OR) was obtained for OCDD: 401-1000 pg/g lipid yielded OR 3.8, 95% confidence interval (CI) 0.4-39, > 1000 pg/g lipid gave OR 5.2, CI 0.4-72. When the lipid OCDD variable was examined as a continuous risk factor there was a 1.09 (9%), CI 0.95-1.25, increase in the adjusted OR for breast cancer per 100 unit (pg/g lipid) increase in OCDD. No differences were found between cases and controls for the other six tested PCDDs. Mean concentration of TCDD was in the cases 3.6 (1.0-7.9) and in the controls 3.3 (1.1-6.3) pg/g lipid. For PCDFs no significant differences were found between cases and controls. The results were not changed if oestrogen or progesterone receptor status, S-phase fraction and DNA ploidy were considered. Breast tissue concentration of OCDD was increased in cancer patients, whereas the concentrations of other PCDDs and PCDFs were equal in cases and controls. 相似文献
3.
R.M. Scanlan W.A. Barletta D. Dell'Orco A.D. McInturff A. Asner E.W. Collings P.F. Dahl H. Desportes A. Devred R. Garre E. Gregory W. Hassenzahl M. Lamm D. Larbalestier D. Leroy P. McIntyre J. Miller T. Shintomi H. ten Kate S. Wipf 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1996,380(3):544-554
4.
Thermal maturation of Swedish Alum Shale kerogen and bitumen has been determined from core samples from Eastern and Central Sweden. In samples from Eastern Sweden (Öland and Gotland), the kerogen and bitumen are thermally immature with respect to petroleum generation. In some areas of Central Sweden (Närke, ÖstergÖtland, and Kinnekulle in VästergÖtland), the kerogen is immature, whereas the bitumen is marginally mature to mature. In other areas of Central Sweden (Halleberg-Hunneberg in VästergÖtland), the kerogen is supermature and the bitumen mature. This suggests that bitumen from a mature source-rock has migrated into the Alum Shales of Central Sweden. Migration in Central Sweden is further evidenced by the occurrence of obviously-migrated bituments in vugs and voids in the organicpoor Ordovician limestone overlying the Alum Shale in Central Sweden, and in concretions within the Alum Shale itself. Based on biomarker distributions of extracted bitumen, Alum Shale kerogen pyrolysate and obviously-migrated oils, and the fact that the Alum Shale in most of the areas studied is the only petroleum source-rock extant, it is suggested that the migrated bitumen in Central Sweden is from the Alum Shale itself. Bitumen has migrated from areas where the Alum Shale is in close proxmity to Permo-Carboniferous intrusions, such as Halleberg-Hunneberg, into nearby areas such as Närke and ÖstergÖtland, where there is no evidence of intrusion and the indigenous organic matter is thermally immature. Other areas, where Alum Shales were associated with intrusions and consequently sourced oil, may have been eroded away. There are producing wells on the island of Gotland, where the Alum Shale is also thermally immature. It is therefore assumed that heating which was responsible for generating Gotland's oil was very localized (such as by an intrusion) or that the oil has migrated from a thermally moremature, distant area. On the basis of reservoir rock porosity, and the fact that the Alum Shale of Gotland contains no migrated component, localized heating is favored. 相似文献
5.
KP Nordal E Dahl J Halse A Attramadal A Flatmark 《Canadian Metallurgical Quarterly》1995,10(2):203-206
In an uncontrolled open study 13 patients with moderate to preterminal renal failure were treated with low doses (average 0.36 micrograms/day) of calcitriol up to the time of renal transplantation, which was performed before dialysis had been initiated. A transiliac bone biopsy was obtained both at the start and at the end of the treatment period, the latter coinciding with renal transplantation. All patients who started calcitriol treatment at a creatinine clearance (Ccr) above 30 ml/min had normal bone histology at the time of transplantation, but this was not observed when calcitriol treatment was started at Ccr below 30 ml/min. The study suggests that full benefit of calcitriol at the bone level is obtained only if prophylactic administration is started early in the course of renal failure. 相似文献
6.
7.
This paper presents results of investigations on the influence of loading rate on yielding and fracture behaviour of ferritic steels. The range of loading rates was below a certain level at which a special stress wave analysis is required. Concerning the yielding behaviour it was found, that the yield strength can be predicted by the model of thermally activated flow. The strain hardening dσ/dε appeared to be independent of strain rate, if adiabetic heating can be neglected. Concerning the fracture behaviour it is demonstrated that the Klc-T-curves are shifted to higher temperatures with increasing loading rate. The temperature shift could be correlated with the strain rate sensitivity m = d lnσ/d lnε. The ductile/brittle transition temperature increases with incrasing loading rate. For the upper shelf region crack resistance curves as a function of loading rate are presented. It is shown that the crack length can be determined using the key-curve-method. A slightly increasing tendency of the evaluated JR-curves was found. 相似文献
8.
Effects and side effects of injectable depot steroid in the treatment of allergic rhinoconjunctivitis (hay fever) are described. A few controlled studies have shown injectable steroids to be superior to the effect of placebo and locally applied steroid. Over a period of 10 years from 1984-95 only 26 registered side effects were reported to the central Danish register for side effects of drugs (Laegemiddelstyrelsens Bivirkningsregister). Only eight concerned subcutaneous atrophy and in two cases the cutaneous changes persisted. Based on registration of number of treatments in the county of Funen 1996, it is estimated that the use of injectable depot steroids for treatment of hay fever accounts for about 535,000 DDD (defined daily doses corresponding to about 33,000 treatments per year). We conclude that the use of injectable corticosteroids in the treatment of hay fever is common and effective and side effects are very rare. However, injectable corticosteroids should only be used when conventional treatment is not sufficient to control symptoms. 相似文献
9.
Effect of molybdenum on the stress corrosion cracking behaviour of low alloy steels in nitrate solutions under slow strain rate testing conditions CERT tests ($ \mathop \varepsilon \limits^. = 10^{ - 6} {\rm s}^{ - {\rm 1}} $) were carried out in NaNO3 solutions (0.1… 5 mol/l and 25… 90ßC) to determine the critical parameters for stress corrosion cracking. The steels tested were 15 Mo 3, LStE 36 and two laboratory heats with 0.08% C and molybdenum concentrations of 0 and 1%. All cracked specimens were examined metallographically. Different kinds of corrosion attack with and without intergranular features were observed. The critical potential range for intergranular attack is defined by two critical potentials. The negative critical potential is about UH = ?0.2 V. It is hardly affected by the test parameters and the material. All free corrosion potentials lie in this range. All freely corroding specimens failed by intergranular cracking in 5 M NaNO3 at 90°C. Only the coarse grained material without Mo showed intergranular cracks at even lower concentrations of NaNO3. The positive critical potential varied widely over 0 to 0.5 V, depending on the test parameters and the material. Furthermore, in all cases a second critical potential range of intergranular attack was found at about UH = 0.8 V. The potential range of UH = 0.5 to 0.8 V for resistance against intergranular attack disappears with increasing temperature, as with the test conditions according to DIN 50 915 in boiling Ca(NO3)2 solutions. Furthermore, this was observed for the heat without Mo at already 90°C. With respect to environmental parameters, the effect of NaNO3 concentration is very small but the effect of temperature is markedly high. The materials can be better characterized by critical temperatures rather than by critical potential ranges. Unified ranking of the materials with respect to their resistance to intergranular attack is not possible because of its dependence on the potential. However, on the basis of the extent of the domains in which the materials are resistant, it is possible to differentiate among the materials. Their resistance to intergranular attack increases in the following order: Heat without Mo → LStE 36 → 15 Mo 3 → heat with 1% Mo. The effect of Mo is explained in terms of its association with high proportions of bainite in the microstructure. 相似文献
10.
S.R. Dahl 《Chemical engineering science》2005,60(23):6658-6673
Discrete-particle simulations of a gas-solid fluidized bed are used to investigate the species segregation (de-mixing) behavior of systems with continuous particle size distributions. Both Gaussian and lognormal distributions are investigated over a range of distribution widths, restitution and friction coefficients, and gas velocities. The results indicate that: (i) the average particle diameter decreases as the height within the bed increases, (ii) the level of segregation increases with an increase in the width of the particle size distribution, and (iii) segregation is attenuated as bubbling becomes more vigorous. Furthermore, the shape of the local size distribution (i.e., Gaussian or lognormal) is found to mimic that of the overall size distribution in most regions of the fluidized bed. 相似文献