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71.
Let ω be a primitive element of GF(2n), where . Let d=(22k+2s+1-2k+1-1)/(2s-1), where n=2k, and s is such that 2s divides k. We prove that the binary m-sequences s(t)=tr(ωt) and s(dt) have a four-level cross-correlation function and give the distribution of the values. 相似文献
72.
Aminoglycosides (including neomycin B and tobramycin) exhibit poor uptake by eukaryotic cell lines. When the amines of these natural products are converted into guanidine groups, their cellular uptake is dramatically enhanced. We have synthesized BODIPY-containing aminoglycosides and guanidinoglycosides to evaluate their cellular uptake properties. Fluorescence activated cell sorting (FACS) and fluorescence microscopy are used to compare the membrane translocation and the cellular localization of these compounds. Upon guanidinylation, the cellular uptake efficiencies of tobramycin and neomycin B are enhanced by 10-fold and 20-fold, respectively. Guanidino-neomycin B exhibits a highly efficient uptake, superior to a fluorescent poly-arginine peptide. Interestingly, the cellular uptake of this common transduction peptide is inhibited by guanidine-neomycin B, suggesting a similar uptake mechanism for both the arginine-rich peptides and the guanidinoglycosides. 相似文献
73.
Synthesis and anti-HIV activity of guanidinoglycosides 总被引:6,自引:0,他引:6
The new guanidinylation reagent N,N'-diBoc-N'-triflylguanidine was used to efficiently convert multiamine-containing glycosides including kanamycin A and B, tobramycin, paromomycin, and neomycin B to the corresponding fully guanidinylated analogues (guanidinoglycosides). This transformation occurs in the presence of H(2)O under mild conditions. Guanidinotobramycin and guanidinoneomycin B were found to inhibit the replication of the HIV virus with activities approximately 100 times greater than the parent aminoglycosides. 相似文献
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76.
New calculations of the4P0 (1,2,3) therms of LiI** are reported which support those of Weiss against those of Holøien and Geltman. A corresponding revision of the spectral analysis of Berry is proposed. 相似文献
77.
Tor Helleseth 《Discrete Mathematics》1979,28(2):161-171
We construct an infinite sequence of codes with related parity-check matrices. We show how to reduce the calculations of the weight distribution of the coset leaders for all these codes, to the calculation of finitely many numbers Flj. This method is applied in determining the weight distribution of the coset leaders for several classes of codes. 相似文献
78.
It is shown that the effects of doping on the elastic constant and on the Raman frequency of p-type silicon disappear upon application of a stress along [001], with a very similar functional dependence on stress. These experiments prove the intimate relationship between these two phenomena and the degeneracy of the valence bands of silicon. 相似文献
79.
Tor Dokken 《PAMM》2007,7(1):1022203-1022204
Most published work on intersection algorithms for Computer Aided Design (CAD) systems addresses transversal intersections [1], situations where the surface normals of the surfaces intersected are well separated along all intersection curves. For transversal intersections the divide and conquer strategy of recursive subdivision, Sinha's theorem [2] and the convex hull property of NonUniform Rational B-Spline surfaces (NURBS) efficiently identify all intersection branches. However, in singular or near singular intersections, situations where the surfaces are parallel or near parallel in an intersection region, along an intersection curve or in an intersection point, even deep levels of subdivision will frequently not sort out the intersection topology. The paper will focus on the novel approach of Approximate Implicitization to address these challenges. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
80.
A new functional bifacial nucleoside derived from 7-aminopyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione, a Janus-type nucleobase, has been synthesized and incorporated into DNA oligonucleotides. The nucleobase, having self-complementary H-bonding faces, mimics both T and A and engages in the corresponding Watson-Crick-like base pairs, forming stable duplexes. 相似文献