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  • 1
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Chirulen® - a semifinished material from UHMW-PE for surgical implantsThis report deals with the development of the joint replacement, especially concerning Chirulen®. This product consists of a semifinished material from UHMW-PE with extremely high purity grade prepared by the Ziegler low pressure polymerisation process. According to biological and clinical tests Chirulen® has proved its worth as artificial limb material because of its excellent physical properties. Its particular advantages are:1excellent friction and abrasion properties during physiological processes involved in walking, when there is a force of about five times the body weight on the femur bone.2no marked difference in the physical properties at the sterilization with γ-rays.The tendency to replace by an artificial limb other damaged joints, e. g. knee, shoulder, elbow, hand and finger joints is increasing. At these constructions the combination metal/UHMW-PE especially is preferred.
    Notes: Es wird eine zusammenfassende Darstellung über die Entwicklung der Gelenkplastik - insbesondere unter Berücksichtigung von Chirulen®- gegeben. Bei diesem Material handelt es sich um ein Halbzeug aus ultrahochmolekularem Polyäthylen mit sehr hohem Reinheitsgrad, das nach dem Ziegler-Verfahren hergestellt wird. Es hat sich nach biologischen Prüfungen und klinischen Befunden wegen seiner günstigen physikalischen Eigenschaften als Prothesenmaterial gut bewährt. Seine besonderen Vorzüge sind, daß es1während des physiologischen Gangablaufes, bei dem am Schenkelkopf eine Druckkraft von etwa dem 5fachen Körpergewicht auftritt, hervorragende Gleit- und Verschleißeigenschaften zeigt, und2bei der Sterilisation mit γ-Strahlen keine merkliche Änderung in den physikalischen Eigenschaften aufweist.Die Tendenz, auch andere schadhafte Gelenke, wie Knie-, Schulter-, Ellenbogen, Hand- und Fingergelenke, durch eine Prothese zu ersetzen, nimmt stetig zu. Auch bei diesen Konstruktionen bietet sich die Kombination Metall/ultrahochmolekulares Polyäthylen besonders an.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 753-756 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Electronic flow controller ; Advanced flow controller (AFC) ; Pressure programming ; Flow programming ; Automatic optimization ; Split injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An electronic gas-flow controller system called Advanced Flow Control (AFC), which controls not only carrier gas pressure at the column inlet but also the total gas flow including the split flow, was designed and evaluated. BASIC programming of repetitive analyses of standard mixtures under varied split ratios and pressure programs allowed automated optimization of those conditions for the desired column loading and resolution between adjacent peaks.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 308 (1961), S. 23-32 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rhenium pentacarbonyl hydride, a colourless liquid (mp 12.5°) which is sensitive to air is prepared by reaction of alkali pentacarbonyl rhenate(-I) and acid. ReH(CO)5, is considerably more stable than the hydrides of iron and cobalt. Its chemical and physical properties are described. From the infrared spectra of the gaseous samples ReH(CO)5 and ReD(CO)5, the molecule appears to have - like the manganese compound - only low symmetry. The absorption band at 1832 cm-1 and 1318 cm-1, respectively, is assigned to the Re—H-(Re—D-) stretching frequency.
    Notes: „Rheniumcarbonylwasserstoff“, eine farblose luftempfindliche Flüssigkeit (Fp.12,5 °C), bildet sich durch Säurezersetzung der Alkalipentacarbonylrhenate(-I) und zeichnet sich gegenüber den Carbonylhydriden von Eisen und Kobalt durch erhebliche Beständigkeit aus. Sein chemisches und physikalisches Verhalten wird näher charakterisiert. Auf Grund der IR-Spektren der gasförmigen Verbindungen ReH(CO)5 und ReD(CO)5 dürfte der Molekel - ebenso wie MnH(CO)5 - nur geringe Symmetrie zukommen. Die Absorptionsbande bei 1832 bzw. 1318 cm-1 läßt sich der Re—H-bzw. Re—D-Valenzschwingung zuordnen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 1029-1038 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The effect of 40- to 60-mesh hydroxyapatite (HA) granules (Calcitek, Inc., Carlsbad, CA) on the process of primary mineralization during bone healing was examined following insertion of the HA granules into rat tibial bone after marrow ablation. Response to HA was assessed by monitoring morphometric and biochemical changes in matrix vesicles, which are extracellular organelles associated with initial calcification. Following insertion of HA, matrix vesicle-enriched membranes (MVEMs) were isolated from the tissue adjacent to the implant and from the endosteum of the contralateral limb at 3,6,14, and 21 days and from a nonimplanted control group (t = 0). MVEM alkaline phosphatase- and phospholipase A2-specific activities were increased on days 6 (peak) and 14; phosphatidylserine content was also elevated on days 6 and 14 (peak). Comparable changes were seen in the contralateral limb but at lesser magnitudes. Morphological changes were observed as well. The number of matrix vesicles/μm2 matrix increased on days 6 (peak) and 14. The mean diameter of the matrix vesicles was elevated on days 6 (peak), 14, and 21. Mean distance from the calcifying front increased on day 6 but was decreased on days 14 and 21. These results indicated that HA behaves like bone-bonding implants in that there is a stimulation of matrix vesicle enzymes, increased phosphatidylserine content, and increase numbers of matrix vesicles. However, the increases occur only after 6 days postimplantation, indicating a delay in response when compared to normal healing. This delay is confirmed by the morphometric measurements. HA causes a reduction in the response associated with marrow ablation. In addition, the effects of HA are comparable locally and systemically but with different intensity. These observations suggest that osteogenic cells are able to compensate for the inhibitory effects of HA and primary calcification involves normal matrix vesicle production and maturation, if somewhat delayed and reduced in magnitude. The ability to support primary mineral formation may contribute to the successful bonding of HA with surrounding osseous tissue. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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