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  • 1
    Electronic Resource
    Electronic Resource
    Doubt about studies of globin evolution based on maximum parsimony codons and the augmentation procedure (1981)
    Springer
    Journal of molecular evolution 17 (1981), S. 121-122 
    Details
    ISSN: 1432-1432
    Keywords: Globin evolution ; Evolutionary distance estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Both the maximum parsimony method of codon assignment and the augmentation procedure, as used by Goodman and his associates, are liable to serious errors and therefore should not be used for studying molecular evolution in general, and globin evolution in particular.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732684
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  • 2
    Electronic Resource
    Electronic Resource
    A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences (1980)
    Springer
    Journal of molecular evolution 16 (1980), S. 111-120 
    Details
    ISSN: 1432-1432
    Keywords: Molecular evolution ; Evolutionary distance estimation ; Synonymous substitution rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Some simple formulae were obtained which enable us to estimate evolutionary distances in terms of the number of nucleotide substitutions (and, also, the evolutionary rates when the divergence times are known). In comparing a pair of nucleotide sequences, we distinguish two types of differences; if homologous sites are occupied by different nucleotide bases but both are purines or both pyrimidines, the difference is called type I (or “transition” type), while, if one of the two is a purine and the other is a pyrimidine, the difference is called type II (or “transversion” type). Letting P and Q be respectively the fractions of nucleotide sites showing type I and type II differences between two sequences compared, then the evolutionary distance per site is K = — (1/2) ln {(1 — 2P — Q) }. The evolutionary rate per year is then given by k = K/(2T), where T is the time since the divergence of the two sequences. If only the third codon positions are compared, the synonymous component of the evolutionary base substitutions per site is estimated by K'S = — (1/2) ln (1 — 2P — Q). Also, formulae for standard errors were obtained. Some examples were worked out using reported globin sequences to show that synonymous substitutions occur at much higher rates than amino acid-altering substitutions in evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01731581
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  • 3
    Electronic Resource
    Electronic Resource
    Strategy for the synthesis of large peptides: An application to the total synthesis of human parathyroid hormone [hPTH(1-84)] (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 1823-1832 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A strategy suitable for the synthesis of larger peptides is proposed. It involves the following four considerations: (1) all of the side-chain functional groups are protected by benzyl-type protective groups; (2) a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, is used for the fragment-condensation reactions together with 1-hydroxybenzotriazole as the additive; (3) all the protective groups are cleaved simultaneously by the HF method in the final stage of the synthesis; and (4) side products formed are detected and removed by an efficient high-performance liquid chromatography procedure. The usefulness of these procedures is demonstrated taking the synthesis of human parathyroid hormone [hPTH(1-84)] as an example.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360200907
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and conformation of the cyclic octapeptides cyclo(Phe-Pro)4, cyclo(Leu-Pro)4, and cyclo[Lys(Z)-Pro]4 (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2191-2206 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclic octapeptides, cyclo(X-Pro)4, where X represents Phe, Leu, or Lys(Z), were synthesized and their conformations investigated. A C2-symmetric conformer containing two cis peptide bonds was found in all of these cyclic octapeptides. The numbers of available conformations due to the cis-trans isomerization of Pro peptide bonds depended on the nature of the solvent and X residue: they decreased in the following order: cyclo[Lys(Z)-Pro]4 〉 cyclo(Leu-Pro)4 〉 cyclo(Phe-Pro)4 in CDCl3. 13C spin-lattice relaxation times (T1) of these cyclic octapeptides were measured, and the contribution of segmental mobility to T1 was found to vary with the nature of the X residue.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221006
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  • 5
    Electronic Resource
    Electronic Resource
    Computer building of β-helical polypeptide models (1984)
    New York : Wiley-Blackwell
    Biopolymers 23 (1984), S. 23-38 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general method is presented for computing the atomic coordinates of helices in which a dipeptide is the repeating unit. The method will generate both single- and double-stranded model helices having idealized bond lengths and angles, and any arbitrary, user-specified, pitch and number of residues per turn. The variation of inter- and intrastrand hydrogen bonds with pitch and number of residues per turn can thus be examined. An application of the method is the construction of a β-helix having pitch of 6.3 Å per turn and 4.85 residues per turn, a model which can pack nicely into the unit cell of crystals of cation-bound gramicidin A.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360230104
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  • 6
    Electronic Resource
    Electronic Resource
    A peculiar temperature-dependent behavior of iodine species at the formation of chromophore between iodine and aqueous poly(vinyl alcohol) (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 749-755 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The blue colored complex between poly(vinyl alcohol) (PVA) and iodine was prepared at 5°C by mixing an aqueous solution of PVA with an aqueous ethanolic solution of iodine containing boric acid. The absorption spectrum of the system shows bands at 226 nm (A), 290 nm (B), 355 nm (C), and 650 nm (D). Their relative absorbances change largely depending on temperature. When the system is gradually warmed, the chromophoric band D decays and the intensity of band A increases. By lowering the temperature again to 5°C the concentration of chromophore increases. It was found that the decay and the re-formation of the chromophore are reversible in the temperature range 5 to 15°C. Above 15°C, contrarily, hysteresis effects are encountered for the re-formation. Thus, when the chromophore is re-formed at 5°C, the spectra shows an isosbestic point at 420 nm, between bands C and D. The dependence on temperature of bands B and C is quite independent from each other, which strongly indicates that the latter band should be assigned to another iodide species than the I-3 ion (band B) and the I- ion (band A). Based on these experimental data a new mechanism is proposed involving the complex ion I-3 · I2 which is supposed to be a precursor of the chromophoric pentaiodide ion I5-.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021850411
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  • 7
    Electronic Resource
    Electronic Resource
    Cation-binding ability of tactic poly(crown ether)s (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 1579-1586 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cation-binding ability of tactic poly(crown ether)s was evaluated by solvent extraction of alkali metal picrates. It was found that isotactic poly(crown ether)s bind particular cations, which can be easily sandwiched by two neighboring crown ether units, a little more effectively than syndiotactic ones. No difference of cation-binding ability was, however, observed between the corresponding d,l- and meso-bis(crown ether)s. This suggests that the rigidity of the poly(crown ether)s, in combination with the tactic configurations, causes the difference in the cation-binding ability.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820528
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis of a polyvinyl-polyamino acid graft copolymer (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1393-1400 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A copolymer having reactive primary amino groups was synthesized by the copolymerization of styrene and N-methyl-N-(4-vinylphenethyl)ethylenediamine (1). Polymerization of N-carboxy amino acid anhydrides (NCA's) of L-alanine, γ-benzyl-L-glutamate, or β-benzyl-L-aspartate was initiated by the primary amino groups of this copolymer to give a novel polyvinyl-polyamino acid graft copolymer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1982.021830604
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  • 9
    Electronic Resource
    Electronic Resource
    Syntheses of N-(4-substituted phenyl)isocitraconimides and reactivities in their radical copolymerizations with styrene (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 479-488 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Radical copolymerizations of isomeric N-(4-substituted phenyl)isocitraconimides 7a-f and 9a-f (M1) with styrene (ST) (M2) were performed at 60°C, using 2,2′-azoisobutyronitrile as initiator in tetrahydrofuran, in order to study the substitutent effect on the copolymerization parameters. From the results, the monomer reactivity rations were determined as r1 = 0,0,81 ≤ r2 = 1,76 in the 7/ST systems, and r1 = 0, 0,27 ≤ r2 ≤ 0,42 in the system 9/ST. It was found that the relative reactivities (1/r2) of 7 toward the polystyrly radical cannot be correlated by the polar-substituent constant (σ) but by the resonance-substituent constant (ER) in the modified Hammett equation: log(1/r2) = ρσ + γER. Furthermore, the monomer reactivity ratios considering the influence of the penultimate effect were also determined, and the substituent effect of 7 and 9 was studied according to the above equation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021850306
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  • 10
    Electronic Resource
    Electronic Resource
    Noradrenergic axon terminals in the substantia gelatinosa of the rat spinal cord (1982)
    Springer
    Cell & tissue research 222 (1982), S. 359-378 
    Details
    ISSN: 1432-0878
    Keywords: Axon terminals ; Substantia gelatinosa ; Spinal cord ; Noradrenaline ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The noradrenergic terminals in the substantia gelatinosa of the dorsal horn of the cervical spinal cord of the rat were investigated by means of the histofluorescence technique and electron-microscopic cytochemistry using the glyoxylic acid-KMnO4 fixation technique. In accordance with the topographical distribution of fluorescent catecholaminergic fibers, noradrenergic terminals containing small granular vesicles were frequently observed electron microscopically in the outer layer of the substantia gelatinosa. These terminals were most frequently found to appose without showing typical synaptic features, small-caliber dendrites, spine apparatus, and rarely, large caliber dendrites. Only in a few cases, the noradrenergic terminals exhibited typical synaptic contacts with dendritic elements of small size. In addition, noradrenergic terminals apposed non-noradrenergic terminals containing small agranular vesicles. In rats bearing surgical lesions of the dorsal roots, no noradrenergic terminal were found in contact with the degenerated axon terminals in the substantia gelatinosa. These findings suggest that the noradrenergic afferents to the substantia gelatinosa may exert their influence on sensory transmission via dorsal horn cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213218
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