Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Ab Initio-MIA and Molecular Mechanics Studies of the Distorted Sucrose Linkage of Raffinose (1994)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 116 (1994), S. 9590-9595 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00100a025
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Linkage position in oligosaccharides by fast atom bombardment ionization, collision-activated dissociation, tandem mass spectrometry and molecular modeling. L-Fucosylp-(.alpha.1.fwdarw.X)-D-N-acetyl-D-glucosaminylp-(.beta.1.fwdarw.3)-D-galactosylp-(.beta.1-O-methyl) where X = 3, 4, or 6 (1988)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 110 (1988), S. 6931-6939 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00229a001
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Studies of crystalline native celluloses using potential energy calculations (1994)
    Springer
    Cellulose 1 (1994), S. 161-168 
    Details
    ISSN: 1572-882X
    Keywords: cellulose I ; molecular mechanics ; crystal structure ; molecular ; modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Energies for various trial packing arrangements of unit cells for the Iα and Iβ phases of native cellulose discovered by Sugiyamaet al. were evaluated. Both a rigid-ring method, PLMR, and the full-optimization, molecular mechanics program, MM3(90), were used. For both phases the models that had the lowest PLMR energy also had the lowest MM3 energy. Both calculated models have the chains packed ‘up’, O6s intg positions, and the same sheets of hydrogen-bonded chains. The Iβ structure model is essentially identical to that proposed previously for ramie cellulose by Woodcock and Sarko. It is also the same as the best parallel model previously proposed that was based on the X-ray data of Mann, Gonzalez and Wellard, once the various unit cell conventions are considered. Also, the energies from both methods for all three celluloses, Iα, Iβ and II, are in the order that rationalizes their relative stabilites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00819665
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Analysis of the ring-form tautomers of psicose with MM3 (92) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 15 (1994), S. 561-570 
    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: By nuclear magnetic resonance (NMR), the four ring forms of psicose, α-and β-pyranose and α- and β-furanose, have almost equal concentrations in aqueous solution. Prediction of this equilibrium by molecular mechanics tests both the balance within the force field and the methods for including the many degrees of freedom in the system. For both the α- and β-furanoses, each of 410 different ring shapes was studied in combination with 37 combinations of staggered side-group orientations. Of these, 48 and 57 initial combinations of side-group orientations contributed to the α- and β-furanose energy surfaces. The pyranoses were analyzed in two steps. First, the 38 characteristic ring conformations were optimized with the 63 staggered side-group combinations. All combinations that gave the lowest energy at one or more of the 38 shapes (20 combinations for α-pyranose, 15 for β-pyranose) were then optimized with 4912 different ring forms. Ring conformations were generated by fixing nonadjacent ring atoms (two for furanose rings, three for pyranoses) at increments of 0.1 Å from the plane of the remaining three atoms. At a dielectric constant of 4.0, prediction was in fair agreement with the NMR results. Model northern and southern conformers contribute to the furanose equilibrium, and both chairs are important for α-psicopyranose. © 1994 by John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540150508
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Factors controlling relative stability of anomers and hydroxymethyl conformers of glucopyranose (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 19 (1998), S. 1111-1129 
    Details
    ISSN: 0192-8651
    Keywords: anomer ; conformational analysis ; glucose ; molecular orbital theory ; molecular modeling ; quantum mechanics ; solvation ; stereoelectronic effects ; sugars ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The relative energies of 11 different conformers of D-glucose, including different exo-anomeric orientations and at least one of each hydroxymethyl conformer (G-, G+, and T) for each of the two anomeric forms (α and β), were calculated at much more complete levels of quantum mechanical (QM) electronic structure theory than previously available, and relative free energies in solution were calculated by adding rotational, vibrational, and aqueous solvation effects. The gas-phase results are based on very large basis sets (up to 624 contracted basis functions) and the coupled cluster method for electron correlation. Solvation Model 5.4/ AM1 was used to calculate the effects of aqueous solvation. Factors contributing to the relative energies of these conformers have been analyzed. Relative energies varied considerably (up to 4.5 kcal/mol), depending on the theoretical level, and different levels of theory disagreed as to which anomer was lower in energy. The highest-level gas-phase calculations predicted the α-anomer to be lower in free energy by 0.4 kcal/mol (Boltzmann average). Gas-phase energies from several different classical force fields were compared to QM results. The QM structures optimized at the MP2/cc-pVDZ level of theory compared well with experiment for three different crystal structures. In water, the β-anomers were better solvated than the α-anomers by 0.6 kcal/mol (Boltzmann average). Contributions of individual hydrophilic groups to the solvation free energies were analyzed.   © 1998 John Wiley & Sons, Inc.   J Comput Chem 19: 1111-1129, 1998
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Conformational analysis of trehalose disaccharides and analogues using MM3 (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 13 (1992), S. 102-114 
    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: Energy surfaces for the relative orientations of the pyranosyl rings of α,α-, α,β-, and β,β-trehalose and analogues were generated with MM3. Sixteen starting conformations of the rotatable side groups of α,β-trehalose were considered, while only 10 conformations were needed for α,α- and β,β-trehalose because of molecular symmetry. Energies were calculated at 20° increments of the two torsional angles of the glycosidic linkage, but otherwise the molecules were fully relaxed. The structure at the overall minimum for α,α-trehalose agrees well with that found in crystal structures, and also agrees with interpretations of NMR and optical rotation data. The energy surfaces for the three trehaloses differ greatly from each other, but are each similar to those for the corresponding three 2-(6-methyltetrahydropyran-2-yloxy)6-methyltetrahydropyrans. This suggests that linkage type (axial or equatorial) is more important than exocyclic substituents in determining trehalose conformations. A comparison with surfaces from the corresponding 5a-carba trehalose analogues illustrates that the exo-anomeric effect is important in determining disaccharide conformation.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540130113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Availability and disposition of hydroxyl groups on surfaces of crystalline cellulose II (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 445-454 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relative availabilities of hydroxyl groups at C(2), C(3), and C(6) on the D-glucopyranosyl units of a particular, highly ordered hydrocellulose II have been studied by means of the reaction of N,N-diethylaziridinium chloride, which introduces 2-(diethyl-amino)ethyl substituents. The hydrocellulose II was formed by hydrolysis of fibrous cotton cellulose II during 40 min reflux in 2.5M hydrochloric acid and is designated EHC-II (exemplar hydrocellulose II) because it represents the most highly ordered (crystalline) particles in a series of hydrocelluloses. The deviation in the distribution of substituents among the 2-O-, 3-O-, and 6-O- positions of the D-glucopyranosyl units in EHC-II from that in a disordered cellulose, in which the three types of hydroxyl groups are equally available, is the basis for estimated availabilities of the three types of hydroxyl groups on the surfaces of elementary fibrils in EHC-II. The experimental values of relative availabilities of O(2)H:O(3)H:O(6)H for EHC-II were 1.0:0.26:0.72 compared to estimated values of 1.0:0.0:.075 for surfaces of elementary fibrils of an idealized, perfectly ordered cellulose II, a model that is based on intensities of x-ray diffraction peaks.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.170120215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Comments on the proposed helical structure of cellulose I (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1579-1579 
    Details
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160625
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Digital comparison of x-ray diffraction data from cotton textiles (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 1469-1478 
    Details
    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: It is proposed that step-scanned digital x-ray diffraction data from closely similar samples be compared only after averaging several scans. The comparison of averaged data for two samples is shown directly by a running difference curve; more subtle differences are indicated by a running sum of difference curve. In order to compensate for inequalities arising from experimental difficulties, scaling of the two data sets may be optionally accomplished by either equating the total intensity sums or performing a least-squares fitting. Comparison of the two scale factors and consideration of the intercept (background) and resulting standard deviation provide a quantitative estimate of the difference between samples. The proposed techniques are illustrated for hydrocellulose II, cotton treated with acid, flame retardant, and permanent-press agent, and for the experimental differences of intact cloth versus pressed pellet and different beam-current settings on the diffractometer.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1980.070250720
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Rigid- and relaxed-residue conformational analyses of cellobiose using the computer program mm2 (1988)
    New York : Wiley-Blackwell
    Biopolymers 27 (1988), S. 1519-1525 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360270914
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...