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Of Structures (of + structure)

Distribution by Scientific Domains
Chemistry50%
Life Sciences33%

Kinds of Of Structures

  • variety of structure
    		•

    Selected Abstracts

    Recent advances in enantioseparations of peptides by capillary electrophoresis

    ELECTROPHORESIS, Issue 22-23 2003
    Gerhard K. E. Scriba
    Abstract The present review summarizes peptide enantioseparations by capillary electrophoresis with the focus on recent developments. These include the application of new chiral selectors and systematic studies involving series of di- and tripeptides with either common features or with a variety of structures. One section emphasizes mechanistic aspects of the migration order of the enantiomers in cyclodextrin-assisted chiral separations with respect to the complexation constants and the mobilities of the transient diastereomeric complexes. In addition, short paragraphs on the application of chiral capillary electrophoresis to the determination of the stereochemical purity of peptidomimetics and on chiral separations of peptides by capillary electrochromatography have also been included. [source]

    Catalytic epoxide oxidation: a novel access to ,avouring and odorant , -diketones

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2004
    Sylvain Antoniotti
    Abstract The catalytic oxidation of epoxides to , -diketones provides a novel access to a variety of ,avouring compounds and odorants. This alternative synthetic strategy involves an oxidation reaction catalysed by commercially available reagents and affords four cyclic and acyclic , -diketones presenting interesting organoleptic properties. The availability of epoxides, easily obtained by ole,n epoxidation, and the possibility of obtaining , -diketones with a variety of structures gives a high potential to this method. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    A study of ground-structure interaction in dynamic plate load testing

    INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 12 2002
    Bojan B. Guzina
    Abstract A mathematical treatment is presented for the forced vertical vibration of a padded annular footing on a layered viscoelastic half-space. On assuming a depth-independent stress distribution for the interfacial buffer, the set of triple integral equations stemming from the problem is reduced to a Fredholm integral equation of the second kind. The solution method, which is tailored to capture the stress concentrations beneath footing edges, is highlighted. To cater to small-scale geophysical applications, the model is used to investigate the near-field effects of ground-loading system interaction in dynamic geotechnical and pavement testing. Numerical results indicate that the uniform-pressure assumption for the contact load between the composite disc and the ground which is customary in dynamic plate load testing may lead to significant errors in the diagnosis of subsurface soil and pavement conditions. Beyond its direct application to non-intrusive site characterization, the proposed solution can be used in the seismic analysis of a variety of structures involving annular foundation geometries. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    First Heterogeneous Ligand- and Salt-Free Larock Indole Synthesis

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009
    Nelly Batail
    Abstract A new ligand- and salt-free procedure using heterogeneous palladium catalysts for the Larock indole and benzofuran synthesis is reported. After optimisation of the reaction conditions, good to high isolated yields have been achieved for a variety of structures. Recycling studies have shown that the palladium catalysts can be readily recovered and reused. Reactions and recovery of the palladium catalysts can be carried out in the presence of air, without any particular precaution. [source]

    Novel Superalkali Superhalogen Compounds (Li3)+(SH), (SH=LiF2, BeF3, and BF4) with Aromaticity: New Electrides and Alkalides

    CHEMPHYSCHEM, Issue 5 2006
    Fang-Fang Wang Dr.
    Abstract Optimized structures, with all real frequencies, of superalkali superhalides (Li3)+(SH), (SH=LiF2, BeF3, and BF4), are obtained, for the first time, at the B3LYP/aug-cc-pVDZ and MP2/aug-cc-pVDZ computational levels. These superalkali superhalides possess three characteristics that are significantly different from normal alkali halides. 1) They have a variety of structures, which come from five bonding mode types: edge,face, edge,edge, face,face, face,edge, and staggered face,edge. We find that the bonding mode type closely correlates with the Li3SH bond energy. 2) The valence electrons on the Li3 ring are pushed out by the (SH), anion, and become excess electrons, conferring alkalide or electride characteristics on these Li3SH species, depending on the bonding mode type. 3) The highest occupied molecular orbital of each Li3SH species is a doubly occupied delocalized , bonding orbital on the Li3 ring, which indicates its aromaticity. It is noticeable that the maximum negative nucleus-independent chemical shift value (about ,10 ppm) moves out from the center of the Li3 ring, owing to repulsion by the SH, anion. We find that these superalkali superhalides are not only complicated "supermolecules", but are also a new type of alkalide or electride, with aromaticity. [source]

    Developmental craniofacial anthropometry: Assessment of race effects

    CLINICAL ANATOMY, Issue 7 2009
    Reid B. Durtschi
    Abstract Differences in craniofacial anatomy among racial groups have been documented in a variety of structures, but the oral and maxillofacial regions have been shown to be a particularly defining region of variability between different racial/ethnic groups. Such comparisons are informative, but they neither address developmental changes of the craniofacial anatomy nor do they assess or take into account the natural variability within individual races that may account for similar reported, across-group variations. The purpose of this report was to compare,using medical imaging studies,the growth trend of select race-sensitive craniofacial variables in the oral and pharyngeal regions when all races [White, Asian, Black, and Hispanic (AR)] are included versus only a single race category [White (WR)]. Race effect was tested by comparing sex-specific growth fits (fourth degree polynomial model) for AR versus WR data. Findings indicate that the inclusion of all races versus a single race did not significantly alter the growth model fits. Thus, the inclusion of all races permits the advancement of general growth models; however, methodologically, it is best to treat the race variable as a covariate in all future analysis to test for both potential all race effects or individual race effects, on general growth models. Clin. Anat. 22:800,808, 2009. © 2009 Wiley-Liss, Inc. [source]