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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 4 (1998), S. 61-71 
    ISSN: 1075-4261
    Keywords: L-tyrosine ; polarized Raman spectra ; Raman tensor ; ab initio MO calculation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Polarized Raman scattering measurements have been made of a single crystal of L-tyrosine by the use of a Raman microscope with the 488.0-nm exciting beam from an argon ion laser. The L-tyrosine crystal belongs to the space group P212121 (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L-tyrosine-d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3 → ND3 and OH → OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L-tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L-tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm-1 (benzene ring breathing), 642 cm-1 (benzene ring deformation), and 432 cm-1 (Cα-Cβ-Cγ bending). © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: 61-71, 1998
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 25 (1957), S. 159-171 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared absorption spectra of oriented cellulose fibers have been observed using polarized radiation. Natural fibers are in general too thick but swelling them in NaOH solution followed by pressing, washing, and drying is an effective way of obtaining a suitable thickness in the 650-3100 cm.-1 region. The dichroism observed for the bands which can be assigned has been interpreted on the basis of the crystal structure of cellulose. The CH stretching band is polarized perpendicular to the fiber axis, in accord with the previously proposed model of the crystal structure (Meyer and Misch). Because both the CH2 symmetric and antisymmetric stretching bands are polarized parallel, a modification of the previously proposed model is necessary. In the region of CH and OH deformation frequencies (1200-1500 cm.-1) nine bands are observed, of which four are polarized parallel and five, perpendicular, to the fiber axis. Deuteration effect of amorphous cellulose on the spectrum in this region was examined. Probable assignments are given for these bands. In the region of CO and CC stretching frequencies (800-1200 cm.-1) all the bands are polarized parallel to the fiber axis. Observations were also made on deuterated cellulose, i.e., cellulose which had been swelled in NaOD. Of the six OD stretching bands observed, five show parallel dichroism, indicating that the OH bands in cellulose are arranged predominantly parallel to the fiber axis. The OH out-of-plane deformation band at 650 cm.-1 is polarized perpendicular to the fiber axis.
    Additional Material: 7 Ill.
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  • 3
    ISSN: 0263-6484
    Keywords: Cortisone ; immature intestine ; carbohydrase concentration ; de novo synthesis ; turnover ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rats of the carbohydrates as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1107-1111 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 1445-1452 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Since 4-vinylbenzyl N,N-diethyldithiocarbamate (VBDC) polymer easily cleaves at the C - S bond and generates benzyl radical, graft copolymerization of methyl methacrylate (MMA) or 4-vinylpyridine (VPy) onto VBDC polymer is easily performed by UV irradiation. The structural analyses of the graft copolymers are performed through glass transition temperature measurements. The graft copolymers of MMA have one Tg and VPy graft copolymers have two Tg's arising from the main and side chains. It becomes clear that the mode of side chains propagation is significantly different for each of the second monomers used.
    Additional Material: 4 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1791-1802 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Depolarization ratios of Raman bands, excited at 488.0 nm, of guanosine-5′-monophosphoric 4 acid, cytidine-5′-monophosphoric acid, adenosine-5′-monophosphoric acid, thymidine-5′-monophosphoric acid, and uridine-5′-monophosphoric acid have been measured in their H2O and D2O solutions in the spectral region from 300 to 1800 cm-1. For comparison, the disodium salt of 2′-deoxyadenosine-5′-monophosphoric acid was also subjected to the depolarization measurement in its H2O solution. The results have been correlated with possible orientations of the principal axes of the Raman scattering tensors as well as with the relative magnitudes of the tensor components. Results should be useful for future polarized Raman studies of synthetic and natural DNA. © 1993 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
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  • 7
    ISSN: 0006-3525
    Keywords: Raman tensor ; polarized Raman spectrum ; adenine ; uracil, uridylyl(3′-5′)adenosine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polarized Raman scattering measurements have been made of a single crystal of uridylyl(3′-5′)adenosine (UpA) by the use of a Raman microscope with 488.0 nm excitation. The UpA crystal belongs to space group P21 (monoclinic), and Raman intensities Iaa, Ibb, and Ic′c′, have been determined for each Raman band. These intensities correspond to the aa, bb, and c′c′ components of the crystal Raman tensor, where c′ is defined as an axis perpendicular to the crystallographic a axis in the ac plane. From these experimental data, and by taking the known crystal structure into account, anisotropic and isotropic molecular Raman tensors have been calculated for the following 11 normal modes: ring stretching modes of the adenine residue (protonated) at 1560, 1516, 1330, and 715 cm-1; ring stretching modes of the uracil residue at 1696, 1657, 1615, 1228, and 790 cm-1; PO-2 symmetric stretching mode at 1080 cm-1; P( - )O single bond stretching mode at 801 cm-1. These pieces of information of the Raman tensors are considered to be useful for estimating the orientations of the DNA and RNA strands in a biological complex from a polarized Raman spectroscopic measurement of such a complex. © 1998 John Wiley & Sons, Inc. Biopoly 45: 135-147, 1998
    Additional Material: 7 Ill.
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  • 8
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Infrared absorption and x-ray diffraction measurements have been made of D,L-copoly-γ-benzylglutamate fibers (cast from dioxane solutions) with various D/L ratios and with various degrees of polymerization. It was found that each chain of these copolymers consists of a random coil portion and an α-helix portion and that the conformation of the latter is similar to the α-helix of pure poly-γ-benzyl-L-glutamate. It was also found that the fraction of the α-helix portion increases with the degree of polymerization of the copolymer. A simplified polymerization mechanism has been proposed for mixtures of D- and L-amino acid N-carboxyanhydrides. A model of the molecular conformation of the D,L-copolypeptide chains derived from this proposed polymerization mechanism is in good agreement with infrared, x-ray, and other measurements. Based on the results of these observations, we discuss the number of L- or D-residues linked in succession that is required for initiating the formation of an α-helix during the course of polymerization.
    Additional Material: 12 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 4 (1966), S. 837-854 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical density-temperature profile of double-stranded poly(A + U), triple stranded poly(A + 2U), and double-stranded RNA from rice dwarf virus in solutions with and without poly-L-lysine has been examined. When poly-L-lysine is added, more than one melting temperature Tm is observed for poly(A + U) and poly(A + 2U). One of them is considered to correspond to the melting of the polynucleotide molecule free from poly-L-lysine, and another to the melting of a polynucleotide-poly-L-lysine complex. For rice dwarf virus RNA, the Tm assignable to the complex is not found to be lower than 99°C. In every case, however, the hyperchromicity observed at the Tm of the free poly-nucleotide molecule is lowered linearly as the amount of poly-L-lysine added to the solution increases. This fact is taken as indicating that there is a stoichiometric complex formed. The stoichiometric ratio lysine/nucleotide in each complex is determined by examining the relation between the amount of poly-L-lysine added to the solution and the percentage of hyperchromicity remaining at Tm of the free polynucleotide molecule. The ratio is found to be 2/3 for all of the three complexes. A discussion is given on the molecular conformations of four types of polynucleotide-polylysine complex hitherto found: (A) double-stranded DNA plus poly-L-lysine in which the lyslne/nucleotide ratio is 1, (B) three-stranded RNA [poly(A + 2U)] plus poly-L-lysine in which the ratio is 2/3, (C) double-stranded RNA [poly (A + U) or rice dwarf virus RNA] plus poly-L-lysine in which the ratio is 2/3, and (D) double-stranded RNA [poly(I + C)] plus poly-L-lysine in which the ratio is 1/2.
    Additional Material: 11 Ill.
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  • 10
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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