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551.
An integrator is described for the measurement of the time integral ∫0t rpm2dt in preparative ultracentrifuge where linearity exists either (a) between tachometer generator ac voltage amplitude and rpm (e.g., Sorvall RC2-B) or dc voltage and rpm, or (b) between the square-wave frequency from the tachometer generator and rpm (e.g., Beckman L2-65B). The construction and the precision levels of an integrator for Sorvall RC2-B preparative ultracentrifuge in the range 0–10,000 rpm and for Beckman L2-65B preparative ultracentrifuge in the range 0–40,000 rpm are described. 相似文献
552.
The proteins released in vitro by metabolically radiolabeled adult Schistosoma mansoni were identified by 2-dimensional gel electrophoresis. To determine the origin of these proteins, adult worms were fractionated into surface membrane, tegument, and remaining body components, and the electrophoretic patterns of the proteins in the 3 fractions were compared to those of the released proteins. The immunogens present in these fractions then were identified by immunoprecipitation with sera from humans infected with S. mansoni. This analysis indicated that essentially all of the proteins released from the worm were immunogenic, whereas most of the major membrane and tegumental proteins were not reactive with the immune sera. Thus, it appears that the adult worm is defended against immune attack by detection of the host's antibody response against released proteins rather than against proteins-exposed on the worm's surface. 相似文献
553.
Adrenocorticotropin (ACTH)-treated adrenalectomized rats subjected to crush denervation recover sensation and functional movement sooner than saline-treated rats. Axonal regeneration is accelerated, the number of large endplates and the frequency of preterminal branching are increased. ACTH has no effect on either intact or denervated muscles. The ameliorative action of ACTH during regeneration is apparently neurogenic and independent of corticoids. 相似文献
554.
E J Goldsmith C Sheng-Cheng D E Danley R D Gerard K F Geoghegan J Mottonen A Strand 《Proteins》1991,9(3):225-227
Crystals of bacterially expressed plasminogen activator inhibitor (PAI-1) suitable for X-ray diffraction analysis have been obtained from 8% (w/v) PEG 1500, pH 8.25. The space group is P1, and the lattice constants are a = 82.17 A, b = 47.82 A, c = 62.89 A, alpha = 90.00 degrees, beta = 106.90 degrees, gamma = 106.84 degrees. The diffraction limit is 2.3 A, and the unit cell contains two molecules of PAI-1. The crystals contain latent PAI-1 which can be partly reactivated by exposure to denaturants. 相似文献
555.
A technique was developed for the measurement of levels of caesium radionuclides (137Cs+134Cs) in live reindeer, cattle, and sheep and in carcasses from these species. The instrument used was a sodium iodide scintillation detector coupled to a portable multi-channel analyser. Based on a combination of background measurements and measurements of impulses from animals with the detector in different anatomical positions we recommmend the following procedures: Lamb: The detector placed on os sacrum (standing animal). Reindeer: The detector placed between the hind legs (animal lying on its side). Cattle: The detector placed on the back of the standing animal, midway between os sacrum and trochanter major. Average geometrical factors for live animals were estimated. It was a linear correlation between measured activity levels in meat samples and counted impulses per sec in live animals. Geometrical factors were estimated at 95% confidence level with uncertainty between 6–14%. The detection limits varied between 50–200 Bq (becquerel)/kg in areas with ground depositions between 5–200 kBq/m2. Since the winter 1986/87 the technique has been the standard procedure for monitoring slaughter animals and carcasses for radiocaesium activity concentrations. 相似文献