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  • Chemistry  (13)
  • classification  (2)
  • Computational Chemistry and Molecular Modeling  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Numerical taxonomy of Portuguese Tronchuda cabbage and Galega kale landraces using morphological characters (1993)
    Springer
    Euphytica 69 (1993), S. 51-68 
    Details
    ISSN: 1573-5060
    Keywords: Brassica oleracea ; classification ; landrace groups ; morphology ; Portuguese coles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A morphological study was carried out to determine the relationships among Portuguese cole landraces using 58 accessions belonging to: (i) Portuguese Tronchuda cabbage (Brassica oleracea var. tronchuda Bailey syn. var. costata De Candolle, Couve Tronchuda); (ii) Portuguese Galega kale (B. oleracea var. acephala De Candolle, Couve Galega); and (iii) other economically less important coles such as Algarve cabbages (B. oleracea var. capitata L., Couve do Algarve or B. oleracea var. sabauda L., Couve Repolho-lombarda do Algarve). The cole accessions were collected from the growers, studied under field conditions during two consecutive years, and characterized using 46 morphological characters from seedling stage to ripe silique. Morphological data were analysed by numerical taxonomy techniques using UPGMA (Unweighted Pair Group Method Using Arithmetic Averages) and by principal component analysis (PCA). Phenograms based on correlation and distance coefficients showed the existence of 8 main groups (A-H). Five of these groups correspond to Tronchuda cabbage landraces: (A) “Couves de Trás-os-Montes”; (B) “Couves do Minho”; (C) “Couves from Central Portugal”; (D) “Couve Portuguesa”; (E) “Couves from Southern inland Portugal”. The three other groups correspond to: (F) cabbages; (G) miscellaneous coles; and (H) Galega kales. Landrace groups are primarily associated with morphological differences among accessions and secondly with accession geographical origin. The interannual character variation did not affect the clustering patterns of the accessions and therefore the stability of landrace classification. PCA was congruent with the landrace groups defined by the phenograms and gave supplementary information on the usefulness of the characters for the definition of the various groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00021725
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  • 2
    Electronic Resource
    Electronic Resource
    Genetic diversity and taxonomy of Portuguese Tronchuda cabbage and Galega kale landraces using isozyme analysis (1994)
    Springer
    Euphytica 75 (1994), S. 221-230 
    Details
    ISSN: 1573-5060
    Keywords: allozyme variation ; allozyme polymorphism ; Brassica oleracea ; classification ; Portuguese coles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Isozyme analysis was used to study the genetic variation and the genetic relationships of a collection of 48 Brassica spp. including 31 Portuguese coles (Brassica oleracea L.) accessions representative of the different landraces cultivated in Portugal. Other brassicas included in this experiment were Jersey kale, kailaan, common cabbages, broccolis, cauliflower, nine-chromosome wild brassica and turnip. Nine enzymes used in the starch gel electrophoresis included: PGM, PGI, AAT, LAP, TPI, FBP, SOD, IDH and GR. Twenty-one putative loci were revealed, with 3 showing invariance and the other 18 contained 50 alleles. The allelic frequencies at these loci represented by 40 plants per accession were used to calculate the following estimators of genetic variation: % of polymorphic loci, average number of alleles per polymorphic loci, average number of alleles per locus, and index of heterozygosity. The genetic relationships were evaluated considering Nei (1978) and Rogers (1972) genetic distances between each pair of accessions whose matrices were hierarchically clustered by the UPGMA method. The accessions were also studied using the principal coordinate analysis. Portuguese Tronchuda cabbages and Galega kales have shown high genetic diversity in comparison with the other accessions. This indicates their potential variation for use in breeding programs. The UPGMA results show that the 48 accessions, with the exception of B. insularis, B. cretica, and turnip, can be clustered into 6 groups: (a) Portuguese Tronchuda cabbages, Galega kales and Algarve cabbages; (b) common cabbages and kales; (c) Couve Poda do Algarve and broccoli; (d) Algarve cabbage and common cabbages; (e) kailaan; (f) broccoli and cauliflower. The groupings obtained by the isozyme analysis are difficult to interpret considering the origin of the Brassica spp. and the morphological resemblance among the accessions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025607
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  • 3
    Electronic Resource
    Electronic Resource
    Response of a continuous culture of saccharomyces cerevisiae to variation of temperature (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 231-235 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220118
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  • 4
    Electronic Resource
    Electronic Resource
    The Cα—C internal rotation in α-alkyl substituted carbonyls and thiocarbonyls: CH(CH3)2C(=X)YH (X, Y= O or S) (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 12 (1991), S. 1047-1057 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The Cα—C internal rotation in 2-methylpropionic, 2-methylthiopropionic (thiol and thion forms) and 2-methyldithiopropionic acids was studied by the ab initio SCF-MO method using 3-21G and 3-21G + d(0.65S) basis sets. Energies and structures of several conformations of these molecules, determined by gradient geometry refinement, are reported and used to assess the effects of oxygen-by-sulphur substitution on molecular properties. The nature and relative importance of intramolecular interactions involving both the α-methyl substituents and the C(=X)Y (X, Y= O or S) fragment are also discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540120902
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  • 5
    Electronic Resource
    Electronic Resource
    Structures and vibrational frequencies of vanadium (V) oligomers: An ab initio study using effective core potentials (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 17 (1996), S. 1183-1196 
    Details
    ISSN: 0192-8651
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Ab initio molecular geometries and vibrational frequencies of various isolated vanadate species (VO3-4, HVO2-4, H2VO-4, and V2O4-7) were calculated using different pseudopotentials. The relative merits of these were assessed by comparing the calculated molecular parameters with the corresponding values obtained from calculations at all-electron levels and, whenever available, from X-ray studies for the salts. The calculations were extended to higher oligomers (V3O5-10, V4O6-13, and V4O4-12) using the pseudopotential whose basis functions are (10s5p5d)/[2s1p1d] (55/5/5) on vanadium and (4s4p)/[2s2p] (31/31) on oxygen, which yielded the best compromise between accuracy and computational effort. The results indicate a linear centrosymmetric geometry for the isolated V2O4-7 anion. The higher oligomers have less than 180° V(SINGLE BOND)O(SINGLE BOND)V angles, except the noncyclic tetraoligomer which has a linear central V(SINGLE BOND)O(SINGLE BOND)V angle (180°). The cyclic V4O4-12 species presents a planar structure with all the vanadium and bridging oxygen atoms in the same plane. This structure was alrea dy reported for the [(CH3)CNH3][V4O12] salt. The results suggest a lower stability of the linear V4O6-13 species, in agreement with previous reports. © 1996 by John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.1
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  • 6
    Electronic Resource
    Electronic Resource
    Rotational isomers of methyl trans-cinnamate: A Raman study (1991)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 519-523 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman and infrared spectra of methyl trans-cinnamate were measured as a function of temperature in the liquid and solid phases. The temperature dependence of the band intensities established the presence of two conformers in the liquid phase (the s-cis and s-trans forms, with C=C—C=O dihedral angles equal to 0° and 180°, respectively; ΔH(s-trans)-(s-cis) = 3.43 ± 0.84 kJ mol-1) and led to the conclusion that the thermodynamically most stable s-cis form is the only form present in the solid.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250220909
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  • 7
    Electronic Resource
    Electronic Resource
    Temperature-dependent intensities of Raman bands of di-n-butylamine (1987)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 18 (1987), S. 115-118 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra of di-n-butylamine show bands whose temperature-dependent intensities clearly suggest the occurrence of different conformers in simultaneous equilibria. In particular, the Raman spectrum of the solid phase is compared with that of n-nonane in order to identify the more stable conformation. In addition, intensity rations vs temperature for pairs of Raman bands in the CH stretching region exhibit a smooth variation between the liquid and solid.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250180209
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  • 8
    Electronic Resource
    Electronic Resource
    Conformational equilibria for 2- and 3-chlorostyrene: Raman and Fourier transform infrared spectra and ab initio calculations (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 25 (1994), S. 353-357 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ab initio SCF MO calculations at the 3-21G level and the vibrational spectra [Raman and Fourier transform (FT) IR] of liquid-phase 2-chloro- and 3-chlorostyrene are reported. For 2-chlorostyrene, the ab initio calculations predict skew and gauche minima, with an energy difference of 11.5 kJ mol-1, and no evidence of more than one conformer was found in the liquid-phase Raman and FTIR spectra. The Raman spectra of liquid 3-chlorostyrene show pairs of bands whose temperature-dependent intensities clearly suggest the occurrence of a conformational equilibrium. From these bands, assigned to non-planar cis and trans conformers, a trans-cis energy difference of 2.3 ± 0.5 kJ mol-1 was obtained for the liquid phase.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250250511
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  • 9
    Electronic Resource
    Electronic Resource
    Meta-substituted styrene molecules included in cydodextrins: A Raman spectroscopic study (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 25 (1994), S. 599-605 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra of styrene (S), 3-fluorostyrene (3FS), 3-chlorostyrene (3CS) and 3-methylstyrene (3MS) and their complexes in α-, β- and γ-cyclodextrins (α-, β-, γCD) were recorded at various temperatures. The substituted styrene molecules were found to provide good group frequencies, namely, vC=C and vC—H, for probing the guest molecules. Generally, the C=C oscillator is shown to be a good probe for studying conformational equilibria of the guest molecule perturbed by complex formation with the various CD molecules. The CH oscillators provide information concerning plausible structures for the complexes. On the whole, all the spectral observations are consistent with different types of structures for the (S, 3MS)-αCD and (3FS, 3CS)-αCD complexes. In particular, the Raman spectroscopic results suggest that, for 3MS-αCD the vinyl group keeps some rotational freedom. For 3FS-αCD and 3CS-αCD, it is suggested that the most electronegative fluorine and chlorine atoms are left outside the the CD cavity, with the vinyl group rotationally hindered. For the γCD complexes, the wider CD cavity sould be able to accommodate all the guest molecules considered keeping the conformer distributions of the pure liquids approximately. However, the inclusion process seems to hinder the internal rotation in such a way that even below 200 K the conformer distribution remains similar to that of the pure liquid at room temperature.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250250721
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  • 10
    Electronic Resource
    Electronic Resource
    Reorientation of methylbenzene molecules in the liquid phase: A comparative Raman band shape analysis (1987)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 18 (1987), S. 497-500 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A comparative Raman band shape study of the reorientation of monosubstituted benzene molecules (C6H5X, X = CH3, CH2Cl, CHCl2, CCl3 and C≡CCH3) in the liquid phase has been performed. Reorientational correlation functions appear to be less sensitive to molecular reorientation about the major axis (Z axis) than to rotation of the axis itself, approaching a symmetric top case. Molecular motion anisotropy is found to increase in the order C6H5CH3 〈 C6H5CH2Cl 〈 C6H5CHCl2 〈 C6H5CCl3 〈 C6H5CCCH3 as the rotation about the Z axis becomes increasingly preferred. These results are in agreement with NMR spin-lattice relaxation data.As expected for liquids with imporatant intermolecular interactions, both the free rotor and Kubo's model fail to fit the experimental correlation functions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250180709
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