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  • 1
    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
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  • 2
    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
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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 17 (1996), S. 1183-1196 
    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
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 519-523 
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 26 (1995), S. 1033-1037 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectra of liquid 3-methylstyrene show pairs of bands whose temperature-dependent intensities clearly suggest the occurrence of a conformational equilibrium. From these bands, assigned to cis and trans conformers, a trans-cis energy difference of 0.8 + 0.2 kJ mol-1 was obtained for the liquid phase. On the other hand, ab initio calculations at the 3-21G** and MP2/3-21G* levels predict a cis form more stable than the trans form by less than 0.15 kJ mol-1, in good agreement with gas-phase literature results.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 25 (1994), S. 599-605 
    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
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  • 8
    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 ethylmethylamine and ethylmethylamine-N-d, both in the liquid phase, at different temperatures, and in the solid phase were recorded. Additionally, Fourier transform IR (4000 - 400 cm-1) spectra of these compounds in the liquid phase were also obtained. Normal coordinate calculations were performed for each conformer (T, G and G′), using an optimized local symmetry force field for secondary amines. These calculations allowed the assignment of the vibrational spectra, in good agreement with the experimental evidence. Whereas in the liquid phase all the three possible conformers were detected, in the solid phase only the bands ascribed to the T conformer were observed. From the temperature dependence study of the Raman spectrum of the liquid, the enthalpy differences between conformers were determined, yielding the values 4.6 ± 0.3 kJ mol-1 for ΔHG′-T′ 3.6 ± 0.3 kJ mol-1 for ΔHG - T and 1.1 ± 0.3 kJ mol-1 for ΔHG′- G. These were compared with ab initio SCF-MO results, for the isolated molecule, in order to assess the relative importance of intra-and intermolecular effects on conformational equilibria.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 13 (1982), S. 56-62 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The N—H, C—H and C—C stretching regions at 3100-3400 cm-1, 2800-3000 cm-1 and 1000-1150 cm-1, respectively, and the low-frequency accordion-like vibration region, have been investigated by Raman spectroscopy for the octyl-, nonyl-, dodecyl-, tetradecyl- and hexadecyl-normal primary amines series, at different temperatures and for different physical states. The spectra were interpreted in terms of structural changes, particularly of the conformations of the paraffin chains, the chain length and the physical state. The changes in the N—H region were associated mainly with molecular association, whereas the changes in the other spectral regions studied were associated mainly with the molecular packing of the chains.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 397-402 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectra of liquid 3-fluorostyrene show pairs of bands whose temperature-dependent intensities clearly suggest the occurrence of a conformational equilibrium. From these bands, assigned to cis and trans conformers, a trans-cis energy difference of 0.70 ± 0.20 kJ mol-1 was obtained for the liquid phase, higher than the reported gas-phase microwave and ab initio values. The effects of dilution with several solvents of different polarity properties are reported and the improved relative stability of the cis form in high-polarity solvents is interpreted in terms of medium effects on intramolecular through-space dipole-dipole interactions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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