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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 39-42 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new type of instrument has been designed and built to make Fourier transform nuclear-magnetic-resonance (NMR) spectroscopic measurements at temperatures to at least 1200 °C, with a resolution of about 1 ppm. A sample is rapidly and repeatedly shuttled between the furnace and the radio frequency (rf) coil of the NMR probe (both located within a high field superconducting magnet), spending most of the time in the furnace. During each cycle, a series of rf pulses may be given and a single free-induction decay sampled. The rf coil is located outside of the furnace and is maintained at room temperature despite its close proximity to the sample. Electronic stability and coil "filling factor'' are thus both optimized. The sample temperature drops below that of the furnace when cycling begins, but rapidly approaches a nearly constant value with only small fluctuations. 99% BN has been successfully used as a sample container in experiments on 27Al, 29Si, and 23Na in molten silicates in the system Na2O–Al2O3–SiO2.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In vivo activated T cells could be isolated from cerebrospinal fluid (CSF) of a patient suffering from chronic meningitis of unclear origin. Although the patient's skin reactivity to purified protein derivative (PPD) was negative, and peripheral T cells did not proliferate to this antigen in vitro, the majority of T cell clones from CSF specifically recognized PPD on either autologous or allogeneic HLA class II compatible macrophages. Remarkably, peripheral blood mononuclear cells potently suppressed the PPD-specific proliferate responses of healthy donors. The selective enrichment of oligoclonal IgG in the CSF but not in the patient's serum further indicated T and B cell responses lacking systemic feedback control. Analyses of a persisting immune stimulation in the CSF provide a potent diagnostic tool and may explain neurological complications as observed in a number of autoimmune diseases and chronic infections.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1600-065X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Research in nondestructive evaluation 1 (1989), S. 65-75 
    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of a crack on time-of-flight of shear waves (4.5 MHz) polarized in perpendicular (t ⊥) and parallel (t ‖) directions to the crack surface, propagating parallel to the direction of crack growth is investigated. The first and second back-wall echoes are used instead of the weak crack-tip echo for the measurement of time-of-flight. The measurement is made for fatigue cracks grown by different loading histories in ferritic steel (pressure vessel steel A533B-1) under the condition of no loading. The normalized time-of-flight (t ⊥−t ‖)/t ⊥ at the crack position is found to change proportionally as the ratio of crack depth to specimen width increases. The change is mainly due to the effect of plastic deformation occurring around the crack ont ‖. It is shown that the depth of tightly closed fatigue crack in austenitic stainless steel (AISI 304) also can be evaluated under the condition of no loading by using this relationship.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The apparatus developed for high-temperature liquid-state NMR will be described in detail elsewhere. A sample in a 1-cm diameter boron nitride capsule is rapidly shuttled 15 cm between a furnace and a room-temperature radio frequency NMR coil, spending 10 s in the former and -0.5 s in the latter ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 70 (1987), S. 237-253 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents For fast calculation of modal components in three-phase-systems nonrecursive filtering is normally used. By application of these method on the αβ-components instead of originalRST-values the necessary amount of arithmetic calculation can be cut by one third. — During transients the calculation can be accomplished within a quader of a period with a step-by-step adjustment of the filter order, if the time of change-of-state is known. — The behaviour of Fourier- and Kalman-Algorithms with and without using the aperiodic decay in the determination of the filter is shown by the transfer-functions in frequency domaine and with two examples in time-domaine.
    Notes: Übersicht Zur schnellen digitalen Ermittlung der Modalkomponenten in Drehstromsystemen werden in der Regel nichtrekursive Filterverfahren verwendet. Durch die Anwendung dieser Verfahren auf die αβ-Komponenten läßt sich im Vergleich zu denRST-Originalgrößen der Rechnaufwand etwa um ein Drittel reduzieren. Bei Übergangsvorgängen kann die Berechnung durch schrittweise aufbauende Filter bis auf eine Viertelperiode verkürzt werden, wenn sich der Zeitpunkt der plötzlichen Zustandsänderung feststellen läßt. — Das Verhalten von Fourier- und Kalmanalgorithmen mit und ohne Berücksichtigung des aperiodischen Gliedes im Filteransatz wird durch die Übertragungsfunktionen im Frequenzbereich und anhand zweier Beispiele im Zeitbereich vorgestellt.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new method for the histochemical demonstration of pyruvate kinase (PK) activity was developed using a semi-permeable membrane and ATP-dependent phosphorylation of glucose coupled with tetrazolium reduction via glucose-6-phosphate dehydrogenase (G6PD) in order to investigate normal liver tissue nd neoplastic hepatic nodules induced by thioacetamide (TAA). A series of control reactions and comparison with microbiochemical analysis of microdissected lyophilised material were used to determine the specificity of the reaction. In agreement with earlier reports, an activity gradient in control liver decreasing from zone 3 to zone 1 was apparent both histochemically and after biochemical analysis. Liver neoplastic nodules induced by 25 weeks dietary thioacetamide administration and characterized by increased G6PD demonstrated a clear decrease in PK activity. In contrast, epithelial cells within areas of cholangio-fibrosis thought to be direct precursors for cholangioccllular tumour development were characterized by a strong increase. Comparison of the results with immunohistochemical and biochemical data from the literature indicate that the specific histochemical method described will be of great assistance in future assessment of disease and physiological alteration in activity of this key enzyme of glycolysis.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 10 (1988), S. 317-322 
    ISSN: 1279-8517
    Keywords: Pedicle ; Thoracolumbar ; Spine ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les caractéristiques géométriques de 380 pédicules vertébraux, compris entre T6 et L5, ont été analysées. Les différentes mesures ont été pratiquées directement sur les pièces anatomiques et sur leurs images radiographiques. Le diamètre horizontal et vertical du pédicule vertébral, son angle avec le plan transversal et sagittal, le diamètre transversal et ventrodorsal du canal rachidien et du corps vertébral ont été pris en considération. La longueur du pédicule seule, ainsi que sa longueur associée à celle du corps vertébral jusqu'au cortex ventral ont été mesurées le long de l'axe pédiculaire et sur une ligne parallèle à la ligne médiane. Les diamètres pédiculaires horizontaux et verticaux les plus étroits ont été mis en évidence aux niveaux compris entre T6 et T10. La corrélation entre la largueur pédiculaire et la dimension des vis utilisées en clinique est évidente. Sur le plan transversal, le pédicule forme un angle plus ou moins divergent à partir du corps vertébral, à l'exception de T12. Sur le plan sagittal le pédicule a une direction crâniale de T6 à L3 et légèrement caudale pour L5. La connaissance de la distance comprise entre la limite dorsale du pédicule et le cortex ventral du corps vertébral est très importante pour pouvoir insérer une vis avec sûreté. Cette distance est significativement plus grande le long de l'axe pédiculaire par rapport à une ligne parallèle à l'axe médian à tous les niveaux sauf pour T12.
    Notes: Summary The geometric properties of 380 vertebral pedicles, ranging from T6 to L5, were analysed. Measurement were made directly from the specimens as well as from roentgenograms. The parameters considered were the horizontal and vertical pedicle diameters, pedicle angles in the transverse and sagittal planes, and the transverse and anteroposterior widths of the spinal canal and vertebral body. In addition, the length of the pedicle and the length of the pedicle including the vertebral body to the anterior cortex were measured along the pedicle axis and in a line parallel to the midline of the vertebral body. The smallest horizontal and vertical pedicle diameters were found at vertebral levels from T6 to T10. The correlation between pedicle widths and screw dimensions is obvious. In the transverse plane, the pedicle angle diverged from the vertebral body at all levels, except at T12. In the sagittal plane, the pedicles were angled cephalad from T6 to L3 and slightly caudally at L5. Knowledge of the length of the pedicle to the anterior vertebral body cortex is very important for safe screw purchase. At all levels, with the exception of T12, this length was found to be significantly greater along the pedicle axis than along a line parallel to the midline of the vertebral body.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 52 (1986), S. 305-315 
    ISSN: 1432-0584
    Keywords: T Cell Clones ; Myelopoiesis ; CFU-GM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Regulatory effects of mixed lymphocyte culture (MLC)-derived CD4+ human T cell clones on granulocyte-macrophage colony (CFU-GM) formation by normal bone marrow (BM) were studied in an initial attempt to establish an in vitro model for the negative feedback control of myelopoiesis by alloactivated T cells. This is likely to be of clinical significance in the aberrant control of haematopoiesis during some cases of graft-versus-host disease (GVHD) after allogeneic BM transplantation. Whilst 5 such alloproliferative clones generally failed to suppress CFU-GM, the majority of clones with natural killer (NK)-like activity [10], or those with suppressive activity in MLC [2], regularly and strongly suppressed in this system, reinforcing the view that certain T cells may have potent negative regulatory effects on haematopoiesis.
    Type of Medium: Electronic Resource
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