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  • 1
    Electronic Resource
    Electronic Resource
    COMPUTED TOMOGRAPHY OF THE NORMAL CANINE LUMBOSACRAL SPINE: A MORPHOLOGIC PERSPECTIVE (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Veterinary radiology & ultrasound 37 (1996), S. 0 
    Details
    ISSN: 1740-8261
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The lumbosacral spine of six normal dogs weighing 4.5 to 24.5kg was imaged by computed tomography in 5.0 mm & 10.0 mm transverse planes. The vertebral canal and thecal sac (including emerging nerve roots not distinguished as separate structures from the spinal cord) were measured along dorsoventral and transverse dimensions at cranial, middle and caudal levels within each vertebra from transverse tomographic images. Linear measurements were standardized to the dorsoventral dimension of the L6 vertebral midbody to permit comparison and averaging of the vertebral and thecal sac dimensions among different sized dogs. The dorsoventral and transverse vertebral canal size progressively increased from cranial to caudal within each vertebra from L1−L6 (p ≤ 0.05). The transverse dimension of the thecal sac image increased caudally within each vertebra from L1−L4 (p ≤ 0.05). The vertebral canal dorsoventral and transverse dimensions were largest in the midlumbar area (p ≤ 0.05). The transverse, but not the dorsoventral, imaged dimension of the thecal sac peaked in the L4 vertebra (p ≤ 0.05). The dorsoventral thecal sac image was observed to fill the vertebral canal in the cranial and middle vertebral levels in vertebrae L1 through L5 in over 60% of these normal dogs. However, epidural fat could almost always be seen lateral to the thecal sac regardless of what lumbar vertebra or vertebral level was imaged. Cranial to the lumbosacral junction, the dorsal intervertebral disk margin was almost always concave relative to the thecal sac. However, at the L7-S1 junction, some dogs had flat or even slightly convex dorsal intervertebral disk margins. The dorsal and ventral longitudinal ligaments and the ligamentum flavum could not be identified as distinct structures on the 5.0 mm transverse tomographic images.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1740-8261.1996.tb01250.x
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  • 2
    Electronic Resource
    Electronic Resource
    Stereoisomere Aromastoffe (1991)
    Springer
    European food research and technology 192 (1991), S. 209-213 
    Details
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Zusammenfassung 5-Alkyl-substituierteδ-Lactone finden sich als aromarelevante Substanzen in tierischen Fetten, aber auch in einigen Früchten. Vor kurzem gelang die erste direkte gaschromatographische Stereodifferenzierung einigerδ-Lactone an der chiralen Phase Oktakis(3-O-butyryl-2,6-di-O-pentyl)-γ-cyclodextrin [4]. Es wird nun die Enantiomerentrennung derδ-Lactone bis zu den langkettigen Verbindungenδ-Trideca-(δ-C13-)- undδ-Tetradeca-(δ-C14-)-lacton aufgezeigt. Über optisch reine Referenzsubstanzen konnte die Elutionsfolge S(I), R(II) der drei wichtigsten aromarelevanten Vertreter dieserδ-Lactonklasse bestimmt werden. Die Enantiomerenverteilung der C8-, C10-, C12-δ-Lactone im Wasserdampfdestillat verschiedener Milchprodukte (Milch, Sahne, Butter), in Margarine sowie im Kokosnußfleisch wurde exemplarisch mit Hilfe der HRGC, auch unter Einsatz der multidimensionalen Gaschromatographie (MDGC), untersucht. Es zeigten sich charakteristische, substratspezifische Enantiomerenverteilungen. Die Verteilungsmuster der untersuchten Spiegelbildisomeren aus Kokosnüssen unterschieden sich wesentlich von denen der Milchprodukte.
    Notes: Summary 5-Alkylatedδ-lactones are well known flavour compounds in animal fats and also some special kinds of fruit. Recently, the first direct stereo-differentiation of chiralδ-lactones was reported using Oktakis(3-O-butyryl-2,6-di-O-pentyl)-γ-cyclodextrin as the chiral stationary phase [4]. The enantiomeric separation ofδ-lactones up to the long-chain compoundsδ-trideca-(δ-C13−) andδ-tetradeca-(δ-C14−)-lactone is demonstrated. By means of optically pure references, the order of elution S(I), R(II) was determined for the important flavour compoundsδ-octa-,δ-deca-, andδ-dodecalactone. Analysis of the steam distillate of some dairy products (milk, cream, butter), of margarine and of coconut has been carried out, in order to yield the enantiomeric distribution of C8-, C10- and C12-δ-lactones by HRGC and multidimensional gas chromatography. Characteristic and product-specific ratios ofδ-lactone enantiomers are detected. The pattern of enantiomeric composition ofδ-octa-,δ-deca-,δ-dodecalactone in coconuts differs completely from that found in the dairy products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01202880
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  • 3
    Electronic Resource
    Electronic Resource
    Stereochemical analysis of constituents of essential oils and flavor compounds by enantioselective capillary gas chromatography (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 328-332 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Cyclodextrin derivatives ; Terpenoid hydrocarbons ; Chiral carbonyl compounds ; Flavor alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Modified cyclodextrins interact enantioselectively with a great variety of volatile chiral constituents of essential oils by forming diastereomeric inclusion complexes. Capillary gas chromatography is used for resolving the enantiomers of terpenoid hydrocarbons (camphene, α-pinene, limonene, α-phellandrene), carbonyl compounds (carvone, fenchone, menthone, isomenthone, piperitone, camphor, myrtenal), and alcohols (trifluoroacetylated β-citronellol, myrtenol, trans-pinocarveol, 1-octen-3-ol, and underivatized linalool). The enantiomeric composition of some of these compounds in a variety of essential oils is investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130507
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  • 4
    Electronic Resource
    Electronic Resource
    New, selectively substituted cyclodextrins as stationary phases for the analysis of chiral constituents of essential oils (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 367-372 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Two-dimensional GC ; Essential oils ; Lavandulol ; α-Bisabolol ; Nerolidol ; Methyl jasmonate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New β- and γ-cyclodextrin derivatives, selectively substituted with n-pentyl and methyl groups, e.g. heptakis(2,6-di-O-methyl-3-O-pentyl)-β-cyclodextrin, octakis(2-O-methyl-3,6-di-O-pentyl)-γ-cyclodextrin, and octakis(2,6-di-O-methyl-3-O-pentyl)-γ-cyclodextrin, have been prepared from specifically protected intermediates. The new cyclodextrin derivatives exhibit unique enantioselectivity towards important chiral constituents of essential oils. The enantiomers of lavandulol, α-bisabolol, nerolidol, and other terpenoid alcohols could be resolved and their presence in different essential oils could be proved. Methyl jasmonate and epi-methyl jasmonate could, in addition, be detected in jasmine concrete by two-dimensional gas chromatography. The enantiomers of the macrocyclic ketone muscone have been separated for the first time.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150603
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