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11.
Two-sector linked-scan analysis of an unpurified proteolytic digest of a pyruvate decarboxylase enzyme (60,000 Da) has allowed the discovery and assignment of an amino-terminal post-translational modification and processing event. A difference in amino acid sequence from that predicted by a recently published nucleotide sequence has also been found. These results illustrate both the use and considerable potential of linked-scan methods for the analysis of complex biopolymer mixtures.  相似文献   
12.
A new cyclic nitrone spin trap, [4-(3′,3′-dibutyl-2′-oxy-3′H-isoindol-5′-yloxy)butyl]triphenylphosphonium bromide (MitoSpin), bearing a lipophilic cation has been prepared by a route that involves a novel Parham-type lithiation-cyclization of an isocyanate to give the isoindolinone core. MitoSpin accumulates in a membrane potential dependent way in energized mitochondria and its oxidation could potentially be used in the study of oxidative stress resulting from reactive oxygen species generated in mitochondria.  相似文献   
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High-spin properties of the nucleus 169Hf have been studied through the fusion evaporation reaction 96Zr(76Ge,3n)169Hf at a beam energy of 310 MeV. The known rotational bands have been extended considerably and 6 new bands have been established, four of which form coupled bands with pronounced M1 connections. Quasiparticle assignments are suggested for the new band structures, and it appears that coupling to vibrational degrees of freedom plays a role. Both coupled bands involve the excitation of quasiprotons. In the region of highest spin, a large alignment gain is interpreted in terms of a mixed crossing where an h 9/2 and an h 11/2 quasiproton provide the two signatures of the aligning configuration. Received: 23 March 2001 / Accepted: 20 September 2001  相似文献   
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Equations have been obtained for determining residual stresses in the wall of a hollow, axially symmetric body consisting of concentric layers of elastically dissimilar materials, all having cylindrical elastic orthotropy. These equations permit residual normal stresses in the radial, circumferential, and axial directions and residual shear stresses on planes normal to the axis of the body to be calculated from measurements of the strains developed on the inner or outer cylindrical surface of the body as thin layers of stressed material are serially removed from the outer or inner surfaces, respectively. The equations are applied to a parametric study of stresses in an elastically isotropic, two-component body to determine the nature of the differences in stresses between the composite body and a homogeneous body as a function of the difference in elastic constants.  相似文献   
17.
In this paper it is shown that any (abstract) polytope is a quotient of a regular polytope by some subgroup N of the automorphism group W of , and also that isomorphic polytopes are quotients of by conjugate subgroups of W . This extends work published in 1980 by Kato, who proved these results for a restricted class of polytopes which he called ``regular'. The methods used here are more elementary, and treat the problem in a purely nongeometric manner. Received January 27, 1997, and in revised form October 1, 1997.  相似文献   
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Summary. In an earlier paper, it was shown that every abstract polytope is a quotient Q = M(W)/N {\cal Q} = {\cal M}(W)/N of some regular polytope M(W) {\cal M}(W) whose automorphism group is W, by a subgroup N of W. In this paper, attention is focussed on the quotient Q {\cal Q} , and various important structures relating to polytopes are described in terms of N ', the stabilizer of a flag of the quotient under an action of W (the 'flag action'). It is pointed out how N ' may be assumed without loss of generality to equal N. The paper also shows what properties of N ' yield polytopes which are regular, section regular, chiral, locally regular, or locally universal. The aim is to make it more practical to study non-regular polytopes in terms of group theory.  相似文献   
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The research of the two last authors has been supported by DGICYT (Spain) PS88-0085.  相似文献   
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