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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 33 (1981), S. 631-639 
    ISSN: 1432-0827
    Keywords: Bone ; Osteopenia ; Noninvasive monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Radiological techniques were utilized for monitoring progressive changes in compact bone in the tibia of monkeys during experimentally induced osteopenia. Bone mass loss in the tibia during restraint was evaluated from radiographs, from bone mineral analysis, and from images reconstructed from gamma ray computerized tomography. The losses during 6 months of restraint tended to occur predominantly in the proximal tibia and were characterized by subperiosteal bone loss, intracortical striations, and scalloped endosteal surfaces. Bone mineral content in the cross section of the tibia declined 17–21%. Tomography demonstrated endosteal widening and reduced mineral content per unit of thickness of cortical bone. In 6 months of recovery, the mineral content of the proximal tibia remained depressed. Effects of the dynamic environment on local-regional changes in various skeletal areas are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 27 (1979), S. 109-115 
    ISSN: 1432-0827
    Keywords: Bone ; Bending rigidity ; Disuse atrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The in vivo bending rigidity and bone mineral content of monkey ulnae and tibiae were measured. Bending rigidity in the anteroposterior plane was measured by an impedance probe technique. Forced vibrations of the bones were induced with an electromechanical shaker, and force and velocity at the driving point were determined. The responses over the range of 100–250 Hz were utilized to compute the bending rigidity. Bone mineral content in the cross section was determined by a photon absorption technique. Seventeen male monkeys (Macaca nemestrina) weighing 6–14 kg were evaluated. Repeatability of the rigidity measures was 4%. Bone mineral content was measured with a precision of 3.5%. Bending rigidity was correlated with the mineral content of the cross section,r=0.899. Two monkeys were evaluated during prolonged hypodynamic restraint. Restraint produced regional losses of bone most obviously in the proximal tibia. Local bone mineral content declines 17 to 24% and the average bending rigidity declines 12 to 22%. Changes in bones leading to a reduction in mineral content and stiffness are discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0827
    Keywords: Microradiography ; Parturition ; Hypocalcemia ; Hypervitaminosis D ; Adult ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une étude microradiographique et histologique de l'os cortical et spongieux a permis de mettre en évidence des remaniements peu profonds chez des vaches, présentant une sévère hypocalcémie et des parésies peu avant la mise à bas. Les surfaces de l'os spongieux et haversien apparaissent inactives et identiques à des coupes de vaches non pleines ou ne fournissant pas de lait. Les surfaces inactives sont lisses et bordées par une zone de radiodensité augmentée. L'absence de réponse ostéoclastique n'est pas due à l'accumulation de tissu ostéoide le long des surfaces d'os haversien et spongieux. La lactation est associée à une augmentation triple de la résorption de l'os spongieux de 7 à 10 jours post-partum chez les vaches témoins. En soumettant les vaches à un régime pauvre en calcium pendant 30 jours, on observe une hypocalcémie significative et une augmentation double de la résorption osseuse. L'adjonction de doses pharmacologiques de vitamine D (30 millions d'unités par jour), du 20ème au 30ème jour de l'administration du régime pauvre en calcium provoque une résorption osseuse additionnelle (environ quintuplée), surtout à la surface de l'os spongieux. L'adjonction de vitamine D empêche le développement de l'hypocalcémie, mais ne produit pas une hypercalcémie décelable. Des concentrations identiques de vitamine D, administrées, pendant 3 à 10 jours, à des vaches, ingérant du calcium et du phosphore à doses normales, provoquent une hypercalcémie et des lacunes de résorption de l'os cortical. La vitamine D semble plus efficace que les régimes pauvres en calcium pour agir sur l'homéostasie du calcium, en modifiant le métabolisme squelettique des vaches adultes.
    Abstract: Zusammenfassung Durch mikroradiographische und histologische Bestimmungen des kortikalen und trabekulären Knochens konnte ein niedriger Knochenumsatz bei Kühen nachgewiesen werden, die kurz vor dem Kalbern ein Syndrom von schwerer Hypocalcaemie und Parese entwickelten. Die trabekulären und Haversschen Oberflächen schienen inaktiv und sahen Schnitten von nicht säugenden und nicht trächtigen Kühen ähnlich. Die inaktiven Oberflächen waren glatt und von einer Zone erhöhter Röntgendichte umgeben. Der Ausfall der Osteoklastenreaktion beruhte nicht auf einer Anhäufung von Osteoid längs der trabekulären und Haversschen Oberflächen. Während der Laktation nahm die Resorption des trabekulären Knochens vom siebten bis zum zehnten Tag postpartum bei Kontrollkühen um das Dreifache zu. Wurden die Kühe während 30 Tagen mit einer calciumarmen Diät gefüttert, so entstanden eine signifikante Hypocalcaemie und eine zweifache Zunahme der Knochenresorption. Wurde vom 20. bis 30. Tag der calciumarmen Diätperiode Vitamin D in pharmakologischen Dosen (30 Millionen Einheiten pro Tag) zugesetzt, so erhöhte sich die Knochenresorption noch mehr (ungefähr um das Fünffache), vor allem längs der trabekulären Oberflächen. Das zugesetzte Vitamin D verhinderte die Bildung einer Hypocalcaemie, verursachte jedoch keine nachweisbare Hypercalcaemie. Gleiche Vitamin D-Dosen, die während 3 bis 10 Tagen an Kühe mit einer normalen Calcium- und Phosphateinnahme abgegeben wurden, verursachten eine Hypercalcaemie und zahlreiche Resorptionsräume im kortikalen Knochen. Es scheint, daß Vitamin D wirksamer ist als eine calciumarme Diät in der Beeinflussung der Calciumhomöostase durch Veränderung des Skelettmetabolismus bei ausgewachsenen Kühen.
    Notes: Abstract Microradiographic and histologic evaluation of cortical and trabecular bone revealed a low turnover in cows which developed a syndrome of profound hypocalcemia and paresis near parturition. Trabecular and Haversian surfaces appeared inactive and were similar to sections from nonlactating-nonpregnant cows. The inactive surfaces were smooth and bordered by a zone of increased radiodensity. The failure of osteoclastic response was not due to the accumulation of osteoid along trabecular and Haversian surfaces. Lactation was associated with a threefold increase in resorption of trabecular bone at 7 to 10 days postpartum in control cows. Feeding a calcium-deficient diet to cows for 30 days resulted in a significant hypocalcemia and a twofold increase in bone resorption. The addition of pharmacologic doses of vitamin D (30 million units daily) from the 20th to 30th day of feeding the calcium-deficient diet further increased bone resorption (approximately fivefold), primarily along trabecular surfaces. The added vitamin D prevented hypocalcemia but did not produce a detectable hypercalcemia. Similar levels of vitamin D administered for 3 to 10 days to cows with a normal calcium and phosphorus intake resulted in hypercalcemia and numerous resorption spaces in cortical bone. Vitamin D appeared to be more effective than calcium-deficient diets in influencing calcium homeostasis by altering skeletal metabolism in adult cows.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 4 (1968), S. 257-261 
    ISSN: 1432-0428
    Keywords: Insulin inhibitor ; serum insulin inhibitor ; insulin-like activity ; nonsuppressible insulin-like activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé 1. L'essai biologique intrapéritonéal pour la mesure de l'insuline a été utilisé pour comparer l'efficacité de l'insuline injectée avec du sérum à celle de l'insuline injectée dans de l'albumine à 5%. La différence d'efficacité a été attribuée à un inhibiteur sérique de l'action de l'insuline sur le muscle. — 2. Pour obtenir une estimation quantitative de cette activité inhibitrice, l'efficacité de l'insuline a été calculée par la soustraction de l'effet du sérum seul de celui de l'insuline ajoutée au sérum. Puisque l'effet de l'insuline est fonction du logarithme de la dose, une telle soustraction exige que les deux formes d'activité «insulinlike». (ILA) soient essentiellement différentes. — 3. Malgré la forte quantité d'ILA dans le sérum, les courbes dose-réponse de l'insuline injectée dans le sérum seul et dans l'albumine sont parallèles; l'analyse de ce phénomène démontre clairement que les effets de l'ILA sérique et de l'insuline ajoutée sont arithmétiquement additifs. — 4. Dans le système d'essai intrapéritonéal utilisé, l'ILA du sérum peut être distinguée de l'action de l'insuline ajoutée, car elle n'est pas supprimée par un puissant sérum antiinsulinique.— 5. Le fait que cette méthode, appliquée aux données de toute une série d'expériences, donne lieu à des résultats consistants, est un élément important en sa faveur.
    Abstract: Zusammenfassung 1. Die Methode der intraperitonealen Insulin-Bestimmung wurde verwandt, um die Wirksamkeit von in Serum injizierten Insulin mit der von Insulin zu vergleichen, das in 5%iger Albuminlösung injiziert worden war. Der Unterschied wurde als Wirkung eines Seruminhibitors der Insulinwirkung am Muskel aufgefaßt. — 2. Um quantitative Anhaltspunkte über die Hemmwirkung zu erhalten, bestimmten wir die Wirksamkeit des Insulins, indem wir die Werte, die sich bei alleiniger Injektion von Serum ergaben, arithmetisch von denen subtrahierten, die bei Injektion von Serum mit Insulinzusatz resultierten. Da die Wirkung des Insulins vom Logarithmus der Dosis abhängt, setzt eine solche Subtraktion voraus, daß sich die beiden Formen der insulin-ähnlichen Aktivität grundsätzlich unterscheiden. —3. Die Dosis-Wirkungskurven verliefen für Insulin, das zusammen mit Serum oder mit Albumin injiziert worden war, parallel trotz erheblichen Serumgehaltes an ILA. Die Analyse der Befunde zeigt eindeutig, daß sich die Wirkungen der Serum-ILA und des zugesetzten Insulins arithmetisch addierten. — 4. Im Unterschied zum zugesetzten Insulin konnte die Serum-ILA in dem von uns verwandten intraperitonealen Nachweissystem auch durch Zugabe starker Anti-Insulin-Seren nicht unterdrückt werden. — 5. Die gute Übereinstimmung in den Ergebnissen, die wir bei der Anwendung dieses Berechnungsverfahrens auf die Daten einer ganzen Reihe verschiedener Experimente erhielten, spricht deutlich zu Gunsten des Verfahrens.
    Notes: Summary 1. The intraperitoneal assay of insulin has been used to compare the effectiveness of insulin injected in serum with that of insulin injected in 5% albumin. The difference was interpreted as being due to a serum inhibitor of insulin action on muscle. — 2. To obtain a quantitative assessment of the inhibitory activity, the insulin effectiveness was estimated by the arithmetic subtraction of the effect of the serum alone from that of the insulin added to the serum. Since the effect of insulin is related to the logarithm of the dose, such a subtraction requires that the two forms of insulin-like activity are essentially different. — 3. Dose-response curves for insulin injected in albumin and in serum were parallel, despite the considerable ILA of the serum; and analysis of the phenomenon clearly shows that the effects of the serum ILA and the added insulin were arithmetically additive. — 4. The ILA of the serum was distinguishable from that of the added insulin in not being suppressed by potent anti-insulin serum in the intraperitoneal assay system used. — 5. The consistency in the results obtained by the application of this procedure to the data of a variety of experiments provides effective support for the procedure.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 3 (1967), S. 287-298 
    ISSN: 1432-0428
    Keywords: Insulin inhibitor ; Serum insulin inhibitor ; Muscle ; Adipose tissue ; Polypeptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé 1. Le dosage biologique de l'activité insulinique selon la technique de l'injection intrapéritonéale a été utilisé pour détecter l'existence d'un inhibiteur sérique de l'insuline. 2. Il a été établi que la solution d'injection permettant d'obtenir un effet insulinique maximum est celle qui contient de l'albumine bovine, à raison de 5 g pour cent. 3. On constate que l'insuline mélangée, soit à du sérum humain normal, soit à du sérum de rats mâles normaux, est moins efficace dans son action sur le diaphragme que l'insuline injectée seule dans la solution d'albumine bovine à 5%. L'effet sur le tissu adipeux par contre demeure inchangé. 4. L'activité inhibitrice ainsi observée est associée à la fraction albumine du sérum. Elle ne disparaît ni après dialyse prolongée du sérum complet ni après celle de la fraction albumine seule. 5. L'activité inhibitrice est libérée de l'albumine quand on fait bouillir celle-ci, le pH étant de 4 à 5. Il semble que la substance obtenue de cette manière soit un polypeptide d'un poids moléculaire de 5000 à 10000.
    Abstract: Zusammenfassung 1. Die Messung der Wirkung intraperitoneal injizierten Insulins am Zwerchfell und am epididymalen Fettgewebe erlaubt den Nachweis von Inhibitoren der Insulinaktivität in der Injektionsflüssigkeit. 2. In einer 5%igen Lösung von Rinder-Albumin hat intraperitoneal injiziertes Insulin einen maximalen Effekt. 3. Die Insulinwirkung am Zwerchfell, nicht aber am Fettgewebe, wird signifikant vermindert, wenn das Hormon zusammen mit Seren von männlichen Ratten und Menschen injiziert wird. 4. Die Inhibitor-Aktivität befindet sich in der Albuminfraktion der betreffenden Seren und wird durch Dialyse des Serums oder der Albuminfraktion nicht vermindert. 5. Sie kann nach Sieden bei pH 4 bis 5 vom Albumin abgetrennt werden. Bei der inhibitorisch aktiven Substanz scheint es sich um ein Peptid mit MG zwischen 5000 und 10000 zu handeln.
    Notes: Summary 1. The intraperitoneal assay of insulin activity has been used to detect the presence of an insulin inhibitor in serum. 2. A solution of 5% bovine serum albumin has been established as an injection medium permitting the maximum insulin effectiveness. 3. When insulin was injected intraperitoneally in serum from male rats or male human subjects, the insulin effectiveness on the diaphragm was reduced compared with that of insulin in 5% bovine albumin; whereas that on the epididymal adipose tissue was unaffected. 4. The inhibitory activity was associated with the albumin fraction of the serum; and neither the inhibitory activity of the serum nor that of the albumin derived from the serum was affected by prolonged dialysis. 5. The inhibitory activity was released from the albumin by boiling at pH 4 to 5. The inhibitory substance appears to be a polypeptide of mol. wt between 5000 and 10000.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 40 (1993), S. 245-274 
    ISSN: 1573-4889
    Keywords: sulfidation ; Fe-Mn-Mo ; FexMo6S8−z ; three-layered scale ; internal sulfidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Iron-base alloys containing ca. 27 a/o (atomic percent) manganese and up to 17.3 a/o molybdenum were sulfidized in H2/H2S gases of 4 Pa sulfur partial pressure at temperatures of 700–1000° C. Three-layered scales developed on all the molybdenum-containing alloys, and an internal sulfidation zone was observed in most cases. The overall scaling process and individual layer growth all followed parabolic kinetics. The outer and intermediate layers comprised Fe(Mn)S and Mn(Fe)S, respectively. Sulfidation rates varied with the morphology and constitution of the inner layer. The reaction product FexMo6S8−z, which was restricted to the inner layer, is permeable to sulfur, iron and manganese, but not molybdenum.For high-molybdenum levels, the overall scaling rate decreased, as a result of the slow diffusion of iron in FexMo6S8−z. For low-molybdenum levels, this beneficial effect is small and outweighed by the formation of an inner two-phase layer.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 21 (1984), S. 103-118 
    ISSN: 1573-4889
    Keywords: duplex steels ; sulfidation ; kinetics ; transport processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two austeno-ferritic stainless steels were sulfidized at temperatures of 783, 873, and 963 K under sulfur pressures in the range 4×10−12 to 3×10−5 atm. In all cases a triplex scale developed, consisting of an outermost layer of (Fe, Cr)1−xS, an intermediate layer of FeCr2S4, and an innermost layer of porous (Cr, Fe)1−xS containing particles of Mo2S3. Parabolic kinetics were observed except at the lowest temperature where one of the steels reacted according to irregular kinetics. The Mo2S3 particles in the innermost layer acted as inert markers, imaging the former positions of the steels' ferrite phase in which Mo is enriched. The lamellar microstructure of the steel was thus reproduced in the innermost sulfide layer. The positions of the Mo2S3 particles together with the porosity of the inner layer are taken to imply inward sulfur transport through this layer and outward metal transport through all three layers.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 34 (1990), S. 161-172 
    ISSN: 1573-4889
    Keywords: transient effects ; steady state ; preoxidation ; sulfidation ; Fe-Mn alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An Fe-27 w/o (weight %) Mn alloy was sulfidized at temperatures of 973, 1073, and 1173 K inflowing H2/H2S/N2 atmospheres corresponding to equilibrium sulfur pressures of 8 Pa. Steady-state parabolic kinetics were always observed after an initial period during which the instantaneous parabolic rate constant increased with time. Product scales were compact and consisted of a layer of Fe(Mn)1−x S over an inner layer of α-Mn(Fe)S. Preoxidation led to a diminution in the subsequent sulfidation rate. Conflicts between differing reports in the literature of the kinetics of this reaction are resolved, and it is concluded that the protective effect expected of an α-MnS layer is in fact possible.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-4889
    Keywords: sulfidation ; Fe−Mo−Al−Mn ; Fe−Mo−Al−Mn−Y ; Fe−Mo−Al−Mn−Zr ; Al2O3, Al0.55Mo2S4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of zirconium and yttrium additions on the sulfidation behavior of an Fe−10Mo−20Al−8Mn(a/o, atom percent) alloy were examined in flowing H2/H2S gas of 4Pa sulfur partial pressure at 900°C. Good scale protection was obtained during the initial reaction stage of the base alloy. However, after 7–8 hr, the formation of internal (Mn,Fe) Al2S4 platelets triggered breakdown of the protective scale. The reaction products of the zirconium-containing alloy were nonprotective. Yttrium addition resulted in an Y(Fe1−xAlx)12 network along the alloy ferrite grain boundaries. Preferential sulfidation of this phase led to almost complete manganese depletion from the engulfed ferrite, and consequently avoided the manganese-promoted scale breakdown.After an even slower initial stage, this alloy sulfidized at a parabolic rate two orders of magnitude slower than that of pure iron. The protection during the initial and following stages was believed to be provided by an Al2O3-containing layer and an Al0.55Mo2S4+FexMo6S8−z layer, respectively. The formation of Al2O3 is thought to be due to oxygen impurities in the H2S gas, which cannot be removed by conventional means.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 36 (1991), S. 409-421 
    ISSN: 1573-4889
    Keywords: Fe-Mn-Cr alloys ; sulfidation ; Cr3S4 ; multilayered scales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Alloys of composition (in weight percent) Fe-10Mn-10Cr, Fe-10Mn-25Cr, and Fe-25Mn-10Cr were reacted at temperatures of 973 and 1073 K with flowing hydrogen-hydrogen sulfide mixtures corresponding to equilibrium sulfur partial pressures of 10−3 and 8 Pa. Sulfide-scale-growth kinetics and morphologies were compared with those found on pure iron and on the binary alloys Fe-25Cr and Fe-25Mn. All alloys reacted according to parabolic kinetics after an initial period of slow approach to this steady state. Of the materials examined, the binary Fe-25Mn showed the slowest sulfidation rates, except at 973 K and a sulfur pressure of 8 Pa, where Fe-10Mn-25Cr had the best performance. Ternary alloys provided improved performance only when a scale layer of Cr3S4 was formed, an event dependent on temperature and sulfur activity. Multilayered scales were always formed on the ternary alloys, and the role of these layers in controlling sulfidation rates is discussed.
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