IZINDABA An anniversary of major medical intere s t passed by virtually unnoticed last month. On 2 April 2003 it was exactly 50 years since the publication of a letter in the journal N a t u re by James Watson and Francis Crick 1. In it, they described the double helix molecular stru c t u re of deoxyribose nucleic acid (DNA) (Fig. 1), a publication which ushered in a new era in medicine. The t...

The traditional Watson-Crick base pairs in DNA may occasionally adopt a Hoogsteen conformation, with a different organization of hydrogen bonds. Previous crystal structures have shown that the Hoogsteen conformation is favored in alternating AT sequences of DNA. Here we present new data for a different sequence, d(ATTAAT)2, which is also found in the Hoogsteen conformation. Thus we demonstrate ...

L. A. Clark and D. Watson (1991) proposed a tripartite model of depression and anxiety that divides symptoms into 3 groups: symptoms of general distress that are largely nonspecific, manifestations of anhedonia and low positive affect that are specific to depression, and symptoms of somatic arousal that are relatively unique to anxiety. This model was tested by conducting separate factor analys...

B. D. Anderson, 1 L. A. C. Garcia, 1,* D. J. Millener, 2 D. M. Manley, 1 A. R. Baldwin, 1 A. Fazely, 1,* R. Madey, 1,4 N. Tamimi, 1,† J. W. Watson, 1 and C. C. Foster 3 Department of Physics and Center for Nuclear Research, Kent State University, Kent, Ohio 44242 Brookhaven National Laboratory, Upton, New York 11973 Indiana University Cyclotron Facility, Bloomington, Indiana 47405 Hampton Unive...

21 Sueoka, N., these PROCEEDINGS, 45, 1480 (1959). 22 Meselson, M., personal communication. 23 Meselson, M., Ph.D. thesis, California Institute of Technology (1957). 24 DeLamater, E. D., Stain Tech., 26, 199 (1955). 25 Watson, J. D., and F. H. C. Crick, Cold Spring Harbor Symp. Quant. Biol., 18, 123 (1953). 26 Delbruck, M., and G. S. Stent, in The Chemical Basis of Heredity, ed. W. D. McElroy a...

Novel Janus-type nucleoside analogues (1a-d) were synthesized. Their pyrimido[4,5-d]pyrimidine base moiety has one face with a bidentate Watson-Crick donor-acceptor (DA) H-bond array of adenine and the other face with an acceptor-donor (AD) H-bond array of thymine. These nucleosides may self-associate through the self-complementary base pair. Indeed, in the solid state, compound 6d displayed a ...

BACKGROUND 5S ribosomal RNA is the smallest rRNA. Its Watson-Crick helices were identified more than 20 years ago, but the conformations of its loops have long defied analysis. One of the three arms of 5S rRNA, residues 69-106 in Escherichia coli, contains a 14-residue internal loop called loop E. The sequence of loop E is conserved within kingdoms, and is terminated by a pyrimidine-rich loop c...

L.A. Clark and D. Watson (1991) proposed a tripartite model that groups symptoms of depression and anxiety into 3 subtypes: symptoms of general distress that are largely nonspecific, manifestations of somatic tension and arousal that are relatively unique to anxiety, and symptoms of anhedonia and low Positive Affect that are specific to depression. This model was tested in 5 samples (3 student,...

We study the directed polymer model for general graphs (beyond $${\mathbb {Z}}^d$$ ) and random walks. provide sufficient conditions existence or non-existence of a weak disorder phase, an $$L^2$$ region, very strong disorder, in terms properties graph walk. some detail (biased) walk on various trees including Galton–Watson trees, range other examples that illustrate counter-examples to intuiti...