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  • 1
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Chiral separation ; Alcohols ; Diols ; Trimethylsilylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic chiral separation of several chiral 2-and 3-alkanols and diols was studied both in their free hydroxyl and in their trimethylsilyl ether forms. First, the derivatization procedure was verified through the identification of the trimethylsilyl ethers formed on the basis of their mass spectra and optimized to obtain quantitative reaction. The optimized procedure was applied to the trimethylsilylation of racemic mixtures of various hydroxyl compounds. The silylation was found to be highly effective in the improvement of the separation of the individual enantiomers. The major advantages of the derivatization process can be summarized as: (i) excellent baseline separation of the enantiomers of the silyl ethers was achieved in contrast to the parent OH-containing compounds, (ii) the sensitivity of detection highly increased, (iii) the separations do not show any significant concentration dependence and finally (iv) the analysis time needed decreased significantly.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Clinical and experimental medicine 148 (1968), S. 81-89 
    ISSN: 1591-9528
    Keywords: Cardiac surgery ; Myocardial revascularization ; Coronary flow reversal ; Myocardial infarction ; Veines of the heart ; Herzchirurgie ; Myokard-Revascularisation ; Coronarflowumkehr ; Myokardinfarkt ; Herzvenen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei Hunden wurde der Einfluß der retrograden Perfusion des Descendens anterior-Gebietes auf die Folgen der Ramus descendens-Ligatur untersucht. Aus den Akutversuchen geht hervor, daß im Coronarsystem eine Flowumkehr zu verwirklichen ist und daß eine echte Gewebedurchblutung stattfindet. Im günstigsten Fall (3 von 23 Tieren) kann die Flowumkehr ein Kammerflimmern verhindern. Diese Vorteile sind aber mit nachteiligen Begleiterscheinungen verbunden. Die Coronarvenen halten dem hohen arteriellen Druck nicht immer stand, weswegen Gewebeblutungen entstehen können; die venösen Kollateralen leiten mehr als 80% des in die Venen einströmenden Blutes vom Descendensgebiet ab, und die Gewebedurchströmung ist ungleichmäßig, weswegen Zirkulationsstörungen und Infarktzeichen im EKG auftreten. Das Problem der Coronarflowumkehr sollte daher mit weiteren, auf Langzeitüberleben ausgerichteten Versuchen abgeklärt werden.
    Notes: Summary The influence of retrograde perfusion of the vena cordis magna on the sequelae of ligaturing the anterior descendens coronary artery was investigated in acute canine experiments. The results prove that a real inversion of the coronary circulation with an effective tissue perfusion can be obtained. In some cases (3 out of 23) the inversion of the flow prevents ventricular fibrillation. Besides these favorable results a few disadvantageous effects have been noted. The high arterial pressure in the venous system may cause extravasations. By the way of venous collaterals more than 80 percent of the blood may be shunted away from the area to be perfused. The tissue perfusion may be irregular. Further studies with experiments designed for long term survival are therefore necessary.
    Type of Medium: Electronic Resource
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