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61.
When neuraminidase-treated sera are analyzed by agarose gel isoelectric focusing, the factor B (BF) banding pattern is reduced to predominantly one major band without cathodically positioned bands. This not only makes unequivocal typing of BF allotypes possible but also the reliable distinction of all BF F subtype phenotypes with delimitation of "BF F subtype variants". With this new method, serum aging affects the BF determination to a lesser extent than when applying methods that separate native sera. We show that sialylation is not responsible for the BF F subtype polymorphism. All of the investigated BF allotype bands, including those characteristic of the subtypes, show functional hemolytic activity. The banding pattern after removal of neuraminic acid residues ranges from pH 6.8 to 7.3 for factor B, from pH 5.3 to 5.9 for the Ba fragment, and from pH 8.2 to 8.7 for the Bb fragment. The protein structure of factor B is also discussed. Eliminating the superimposition of bands in different BF allotypes, as demonstrated by these methods, proved to be necessary for the detection of hypomorphic BF gene products (BF QL), which are expressed by assumed BF*Q0 alleles in heterozygous genotypes. This allows investigation of BF*Q0 alleles on a protein level, which complements molecular genetic approaches. 相似文献
62.
U. Goeschel H. Lee D. Y. Yoon R. L. Siemens B. A. Smith W. Volksen 《Colloid and polymer science》1994,272(11):1388-1395
Thin films of rigid poly(p-phenylene pyromellitimide) (PMDA-PDA) and semi-rigid poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA), prepared by thermal imidization of the respective poly(amic acid) and poly(amic ethyl ester) precursors, were characterized with respect to their optical, thermomechanical and structural properties. Both polyimides exhibit an unusually large anisotropy between the in-plane and out-of-plane refractive indices, with n ranging from 0.198 to 0.216 for PMDA-PDA and from 0.230 to 0.242 for BPDA-PDA, nearly independent of the nature of the initial polyimide precursor, film thickness, and film preparation method. PMDA-PDA films exhibit low coefficients of thermal expansion (CTE's) of 6.5 and 8.2 ppm/C for the acid-derived and the ester-derived polyimides, respectively. In comparison, the BPDA-PDA films show CTE values of 4.3 and 18.0 for the acid-derived and ester-derived samples, respectively, despite the small differences in their optical anisotropies. Wide-angle x-ray diffraction patterns obtained in reflection and transmission for the various samples reveal a strong in-plane chain orientation for both PMDA-PDA and BPDA-PDA polyimides, with somewhat better intermolecular packing order for the ester-derived polyimide films. These effects of chemical structure and precursor on properties and structures of the polyimide films are discussed in light of recent theoretical considerations of semiflexible polymers.Dedicated to Prof E. W. Fischer on the occasion of his 65th birthday 相似文献
63.
Siemens Halske G. Grube F. Oettel H. Reinhardt B. Fetkenheuer E. Cremer P. S. Tutundžic A. Salminen E. R. Caley A. Glazunov J. Krieglstein Dorothy H. Brophy E. F. Smith L. G. Kollock K. Wagenmann M. L. Nichols E. L. Jewett H. Hölemann M. Garcia G. R. Fitterer R. Treje C. Benedicks B. L. Clarke H. W. Hermance Scheermesser E. Schmidt E. Tornow J. Heyrovský W. Kemula K. Suchý J. Prajzler A. Schleicher 《Analytical and bioanalytical chemistry》1933,91(5-6):197-210
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66.
We estimate the effect of core polarization on the spacing between the centroids of the particle and hole shells in the spectra of 208Pb ± 1 nucleon. We find that this spacing (observed to be ≈ 7 MeV) would be larger by 3 to 4 MeV in the absence of the core polarizations due to the isoscalar and isovector fields. Contributions from core polarizations with both high and low frequency are found to be important. 相似文献
67.
We estimate the influence of thermal fluctuations in heavy-ion induced deep inelastic and fusion reactions by means of a one-dimensional Fokker-Planck equation. Approximating the fusion barrier by an inverted harmonic oscillator, we find an expression for the range of angular momenta ΔJ over which the transmission coefficient falls from 1 to 0. Numerically, ΔJ is fairly but not insignificant, and becomes larger for incident energies near the barrier. 相似文献