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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 30 (1982), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Common problems encountered during the determination of the thermal conductivities of tight sandstones are rock specimen-to-heat source contact and complicated sample preparation. An experimental technique using an electromagnetic heat source solves the direct contact problem between the heat source and the sample. Also, it simplifies the sample preparation and reduces the measurement time.A CO2 laser operating in a pulsed mode is used as a heat source with about 500 W output power. Thus, heat losses due to radiation and air convection are negligible. Unpolished penny-sized samples of tight sandstones are irradiated on one side and the temperature is measured on the opposite side. The temperature is recorded with 12-bit accuracy by a digital data acquisition system. Carbon black is used to give the samples a uniform absorption.The transient temperature data are acquired, processed, and interpreted with interactive computer programs. Transients for each sample can be stacked, to improve the signal-to-noise ratio, and normalized. The thermal conductivity is calculated from the rise portion of the transient using a ridge-regression type generalized linear inversion scheme.As many as 20 samples per hour can be measured with this simple but expensive set-up. In the long run, this means a reduction of laboratory expenses. In addition, the resolution of this method is superior to other variable-state measurement methods due to the real time controlled data acquisition and the numerical interpretation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 114 (1992), S. 16-19 
    ISSN: 0942-0940
    Keywords: Subarachnoid haemorrhage ; Saudi Arabia ; cerebral aneurysm ; arteriovenous malformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It has often been claimed that subarachnoid haemorrhage (SAH) is a rare condition in the Middle East. A 7-1/2-year retrospective study was undertaken to substantiate or disprove this claim. It was found that although the condition is less common than the global average, it was not as rare as previously supposed. The pattern of distribution throughout the population, in terms of sex, was significantly different. The possible reasons for this are discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 18 (1994), S. 154-156 
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les modifications osseuses survenant au cours de la drépanocytose sont la conséquence d'une hyperplasie médullaire, d'une ischémie tissulaire et d'un infarcissement liés à l'occlusion vasculaire. Cette étude rétrospective analyse les complications rachidiennes de la drépanocytose observées de 1982 à 1991. Trente-quatre patients ont été traités dans les services d'orthopédie et de neuro-chirurgie de l'Hôpital universitaire King Fahd à Al Khobar. Il s'agissait de 21 hommes et de 13 femmes, âǵes en moyenne de 17.4 ans, avec des extrêmes de 4 à 28 ans. Des modifications structurales du corps vertébral liées à l'hyperplasie médullaire sont survenues chez 44% des patients. Des nécroses avasculaires responsables d'un effondrement du corps vertébral ont été observéees chez 9 patients (26.5%). La spondylite infectieuse, qui constitue la complication la plus grave, a concerné 8 patients (23.5%), dont la plupart ont bénéficié d'une décompression antérolatérale et de greffes osseuses. Nous pensons que le rachis est souvent atteint au cours de la drépanocytose et qu'un traitement agressif et une étroite surveillance sont nécessaires pour éviter des séquelles majeures.
    Notes: Summary Bone changes in sickle cell disease occur due to marrow hyperplasia, tissue ischaemia and infarction due to vaso-occlusion. Between 1982 and 1991 thirty four patients were treated in the Orthopaedic and Neurosurgery Departments of the Kind Fahd University Hospital, Al-Khobar, with spinal complications due to sickle cell disease. There were 21 males and 13 females aged between 4 and 28 years (mean 17.4 years). Structural changes in the vertebral bodies due to marrow hyperplasia occurred in 44% of the patients. Avascular necrosis leading to collapse of the vertebral bodies was seen in 9 (27%) patients. Infective spondylitis was the most serious complication seen in 8 (24%) patients; the majority needed anterolateral decompression and bone grafting. The spine is often affected in sickle cell disease and aggressive treatment with close follow-up is required to avoid disabling complications.
    Type of Medium: Electronic Resource
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