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The synthetic androgen 19-nortestosterone (beta-NT) has been used illegally as a growth promoter in cattle production in the European Union. Elimination of beta-NT and its metabolites in plasma, urine and bile was studied in three cattle with cannulated gallbladders following intramuscular injection at a single site of 500 mg of the laurate ester (NTL) containing 300.5 mg beta-NT. Using enzyme immunoassay quantification, plasma Cmax of free beta-NT was 0.5 +/- 0.15 microgram/L (mean +/- SEM). Concentrations of free beta-NT in plasma were consistently greater than the assay limit of quantification (0.12 microgram/L) for 32.7 +/- 13.42 days. Mean residence time for the beta-NT in plasma was 68.5 +/- 20.75 days. Following sample preparation by immunoaffinity chromatography, high-resolution GC-MS was used to quantify beta-NT and alpha-NT in urine and bile. beta-NT was detected irregularly in urine from two of the three animals post injection. The principal metabolite present in the urine, alpha-NT, was detected for 160.3 +/- 22.67 days post injection. Cmax for alpha-NT in urine was 13.7 +/- 5.14 micrograms/L. Mean urinary AUC0-183 days for alpha-NT was 845.7 +/- 400.90 (microgram h)/L. In bile, alpha-NT was the only metabolite detected for 174.3 +/- 8.67 days post treatment. Cmax for alpha-NT in bile was 40.8 +/- 12.70 micrograms/L and mean biliary AUC0-183 days for alpha-NT was 1982.6 +/- 373.81 (microgram h)/L. Concentrations of alpha-NT in bile samples were greater than those in urine samples taken at the same time. The mean ratio of biliary:urinary AUC0-183 days was 3.0 +/- 0.72. It is concluded that bile is a superior fluid for detection of alpha-NT following injection of NTL, owing to the longer period during which residues may be detected after administration.  相似文献   

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Conclusions A method has been developed at the laboratory for producing refractory oxide fibers with a diameter of 0.5–0.06 mm by the extrusion method. These fibers can be used in the manufacture of composite materials with a high mechanical strength. Fibers with a diameter of 60 have been obtained. After heat treatment and the subsequent measurement of mechanical properties these fibers were used in producing the composite materials: ceramic matrix + ceramic fiber, metallic matrix + ceramic fibers, etc.Translated from Poroshkovaya Metallurgiya, No. 4 (76), pp. 10–13, April, 1969.  相似文献   

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The involvement of mdr1a P-glycoprotein (P-gP) on the tissue distribution of the multidrug resistance-reversing agent SDZ PSC 833 was assessed by use of mdr1a (-/-) mice. The mdr1a (-/-) and wild-type mdr1a (+/+) mice received a 4-h constantrate i.v. infusion (2 micrograms/min) of [14C]SDZ PSC 833. Mice were sacrificed at 0, 0.5, 1, 2 and 4 h during infusion and at 0.5, 1, 3, 8 and 24 h after stopping the infusion. Blood and tissues were analyzed on total (14C) and parental SDZ PSC 833 concentrations. Mdr1a (-/-) mice exhibited increased SDZ PSC 833 accumulation in cerebrum, cerebellum and somewhat in testes and small intestine compared with the wild-type mice. The difference between mdr1a (-/-) and (+/+) brain (cerebrum and cerebellum) penetration depended on SDZ PSC 833 blood concentrations, because this cyclosporin analog apparently governs its own brain penetration by inhibiting the P-glycoprotein pump in mdr1a (+/+) mice. Thus the mdr1a (-/-)/(+/+) ratio of brain concentrations tended to decrease and increase at high and low blood concentrations, respectively. These findings clearly demonstrate the interaction of SDZ PSC 833 with the P-glycoprotein present at the blood-brain barrier. The SDZ PSC 833 distribution in other mdr1a P-glycoprotein-expressed tissues, as well as its metabolism and elimination, was not affected by the mdr1a gene disruption. This suggests that factors other than mdr1a P-gP are involved in the disposition of this multidrug resistance-reversing agent.  相似文献   

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Percutaneous treatments are useful in two, frequent, painful conditions involving the shoulder. In frozen shoulder syndrome, distention arthrography with intra-articular injection of steroid is used to provide pain relief and to improve joint motion. In rotator cuff tendon calcifications, needle aspiration of calcific deposits is used to treat pain. Surgery should be restricted to failures of needle aspiration. The techniques of these procedures are described and their results are reported.  相似文献   

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余佑林  吴爱祥  肖雄 《黄金》2001,22(2):13-16
采场出矿振动助流器是新研制成功的一种安装在出矿口内的辅助出矿设备,工业应用实践表明,该设备配合常规电耙出矿,不仅设备成本低,结构简单,而且基本上解决了出矿过程中因大块卡堵及结拱等严重影响和业作的难题,大幅度提高了电耙出矿的生产能力。  相似文献   

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Conclusions The feasibility is demonstrated of direct processing of fine high-speed steel swarf by a powder metallurgy technique including prepressing, extrusion, and heat treatment operations The process developed enables sintered steel to be produced possessing properties similar to those of standard steel. The true mechanical properties of standard (cast) and sintered (extruded) steels were determined, with the aid of the theory of plasticity of porous materials, by plotting their deformation diagrams. It is shown that the above theory is applicable to materials possessing coarse structural porosity. Quantitative discrepancy was found between compression and tensile curves, resulting from the presence in such materials of isolated nonmetallic inclusions and from the discontinuity of their microstructure, which may be regarded as initial porosity.Translated from Poroshkovaya Metallurgiya, No. 4(208), pp. 35–40, April, 1980.  相似文献   

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Controlled modification of the carboxylic acid moieties of hyaluronic acid with mono- and polyfunctional hydrazides leads to biochemical probes, biopolymers with altered physical and chemical properties, tethered drugs for controlled release, and crosslinked hydrogels as biocompatible scaffoldings for tissue engineering. Methods for polyhydrazide synthesis, for prodrug preparation, for hydrogel crosslinking, and for monitoring biodegradation are described.  相似文献   

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潘志兵  田喜林 《黄金》2000,21(9):28-31
针对金矿石堆浸生产中原有的活性炭吸附、解吸、电解工艺中存在的问题,成功地研制出了吸附解吸电解一体化装置。该装置已在四川省的某些金矿堆浸场投入使用,其吸附率在99%以上,解吸率在98%以上,电解率在99%以上,解吸电解时间10~12h,解吸电解成本只相当于委托外加工费的1/4.  相似文献   

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Nematode infection of cattle treated in their first year at pasture with the fenbendazole slow release bolus ('Bolus group') was compared during the second year with that of untreated cattle. Ostertagia was the most prevalent parasite associated with Cooperia. Except for the Dictyocaulus spp. which caused clinical signs of bronchitis in the 'Bolus' group, the infection during the second year resulted in a moderate response of the cattle whatever the group. Rises in both pepsinogen and gastrin levels were correlated with the number of Ostertagia L3 on herbage. Damages in the abomasal mucosa were more frequent and severe in the 'Bolus' group where more inflammatory signs were observed in spite of a smaller number of worms. Nevertheless, the differences in total weight gains were not significant thanks to a compensatory effect during the second part of the grazing season in the 'Bolus' group. Hypotheses related to a minimum threshold of infection during the first year necessary to develop high enough protection during the second year are discussed. The pathological effects of gastrointestinal nematodes seem to vary more according to the inflammatory response than to the number of worms.  相似文献   

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There is some concern that patients treated by postgraduate students during their specialty training may be disadvantaged in the quality of treatment result and subject to longer treatment times if they are treated by more than one operator. This study analysed the pre- and post-treatment study models of orthodontic patients from a district general hospital department, debonded by one junior member of junior staff in the calendar years 1991 and 1992. All patients were treated using the same pre-adjusted edgewise appliance in both arches. Two groups of patients were identified: patients whose treatment was started and finished by the same operator (registrar A), and those whose treatment was begun by another operator (registrar B), but finished by registrar A. A random sample of 30 patients from each group was selected and the study models at the start and end of treatment were scored using the PAR (Peer Assessment Rating) Index. No significant differences were found between the average PAR scores for each group at the beginning of treatment, or between groups A and B at the end of treatment; the average treatment time for the patients treated by one operator was 17.67 months (SD 4.15 months), while the average treatment time for the patients treated by more than one operator was 26.1 months (SD 6.78 months). Statistically, this difference was highly significant (P < 0.001). A highly linear relationship (R2 = 0.92) was found between the percentage PAR score reduction and the initial PAR score. The findings and their implications are discussed.  相似文献   

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The herbicide residue levels in leaves of Erythroxylum coca var. coca Lam. plants treated with soil applications of tebuthiuron and hexazinone at 3.36 and 6.72 kg a.i. ha-1 were determined in order to estimate the potential for human exposure to these residues from consuming the leaves or cocaine produced from them. Field-grown plants were treated with a commercial formulation of tebuthiuron or hexazinone and leaves were harvested at the first indication of herbicide injury (i.e. chlorosis and/or necrosis) and at the onset of leaf abscission. Herbicide residues were detected by HPLC in leaf samples from both harvests of all plants treated with tebuthiuron or hexazinone. At 3.36 kg ha-1, herbicide residues in the leaves were less than 2 micrograms g-1 dry wt. for both harvests of both experiments. The highest residue levels detected were 5.90 micrograms g-1 dry wt. for tebuthiuron and 7.17 micrograms g-1 dry wt. for hexazinone in leaves from plants treated with the herbicide at the rate of 6.72 kg ha-1 and harvested at the onset of leaf drop. Based on published toxicity data and estimates of leaf consumption, the herbicide residues in leaves of E. coca var. coca plants treated with tebuthiuron or hexazinone at twice the recommended control rates or less would have a negligible contribution to the health risks of individuals who chew coca leaves. Furthermore, based on the most conservative estimates of cocaine yield and herbicide carry over, death by cocaine overdose would occur long before the NOEL for either herbicide was reached.  相似文献   

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In this study, some 1,4-disubstituted thiosemicarbazide, 1,2,4-triazole and 1,3,4-thiadiazole type novel compounds derived from 3-hydroxy-2-naphthoic acid hydrazide were synthesized to screen for their antimicrobial activity. The structures of these substances were elucidated using elemental analysis and UV, 1H NMR, and mass spectral methods. All of these compounds were tested in vitro for their antibacterial and antifungal activity.  相似文献   

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氨法浸出电镀废渣中镍铜的工艺   总被引:1,自引:0,他引:1  
实验采用NH3-NH4+-H2O体系浸出电镀废渣中镍和铜,通过正交试验研究了总氨浓度、氨铵比、液固比、温度、浸出时间对浸出率的影响.结果表明,在总氨浓度为6 mol/L、氨铵比为1∶1、液固比为8∶1、浸出温度80℃、浸出时间3h的最优条件下,镍的浸出率可达到82%,铜的浸出率可达到95%.  相似文献   

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