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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 22 (1987), S. 3095-3102 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Average radial growth rates in induced morphology crystal aggregates (IMCA) of CaCO3 with sheaf-of-wheat morphologies range between 33.4 and 111 μm/day. The growth process has not been found to be diffusion-controlled. Banding structures appearing in this kind of IMCA are explained just like rhythmic structures similar in origin to Liesegang rings, but the banding law in this case being modified by the matrix effect. Genetical models explaining the formation of ribbons with different particle density are also proposed.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Mineralium deposita 6 (1971), S. 167-176 
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Resume Le gisement de Kamoto est constitué de deux corps minéralisés stratiformes séparés par une unité sédimentaire stérile. C'est un gisement de cuivre et de cobalt dont les principales caractéristiques sont brièvement résumées. Audessus du corps minéralisé supérieur, on trouve des couches de dolomie, où la pyrite est le seul sulfure présent. Cette pyrite a été étudiée à l'aide d'une microsonde: tous les grains idiomorphes y sont entourés d'une bordure bien nette, où la teneur en cobalt atteint 4%; les grains d'apparence framboïdale sont également hétérogènes au point de vue de leur teneur en cobalt. La distribution du nickel et du cuivre est décrite. Ces observations apportent um témoignage supplémentaire de l'importance des événements postérieurs au dépôt dans la «Série des Mines» katangaise, tout spécialement en ce qui concerne la géochimie des métaux lourds. Elles démontrent que le «système» constitué par la roche sédimentaire est resté ouvert pendant un certain temps après la sédimentation.
    Notes: Abstract The Kamoto deposit consists of two stratiform orebodies separated by a barren sedimentary unit. It is a copper and cobalt deposit, the main features of which are summarized in the first part of the paper. Above the upper orebody, dolostone beds are found, where pyrite is the only sulfide mineral. This pyrite was investigated with the help of a microprobe: all idiomorphic grains were found to be surrounded by a well-defined rim, where the cobalt content reaches 4%; framboidal grains were also found to be heterogeneous with respect to cobalt. The distribution of nickel and copper is described. These observations afford one more evidence that post-depositional events played an important role in the “Mine Series” of Katanga, especially with regard to heavy metals geochemistry.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The strata-bound fluorite-(barite-)Pb-Zn ore deposits occurring within the more than 3,000 m thick Alpujárride Carbonate Formation of the Betic Cordillera, southern Spain, are linked to two defined stratigraphic positions (within the Anisian and at the Ladinian-Carnian transition) and to definite sedimentary contexts. These are highly restricted lagoons isolated from the open sea by calcarenitic barriers with noticeable development of algal mats in their inner margins. Preevaporitic deposition conditions are usually recognized. The ore-bearing horizons are located either at the transition from evaporitic to normal marine deposition (as in the case of the Anisian ore-bearing horizon) or at the transition from normal marine to evaporite deposition (as in the case of the uppermost Ladinian to lowermost Carnian ore-bearing horizon). These vertical facies changes correspond also to the transitions from predominantly terrigenous (continental and/or coastal) sedimentation to marine carbonate sedimentation (Anisian ore deposits) and vice versa (upper Ladinian-lower Carnian). It is proposed that the ore deposits in the Triassic Alpujárride Formation are controlled by certain facies associations in the lagoonal environment. The depositional environment determines the hydrologic regimes responsible for early diagenetic formation of fluorite and of the related ore minerals in a way similar to that of early-diagenetic dolomite. This hypothesis is consistent with field and petrographic observations and with available geochemical and itotopic data reported in other works. The present investigation intends to underline the role played by surface-linked ore formation processes, i.e., by ore-forming processes essentially linked to the environments in which sedimentation and early diagenesis takes place, in the genesis of numerous strata-bound Zn-Pb-(F-Ba) ore deposits in carbonate rocks.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1432-5233
    Keywords: Diabetes ; Duodenum ; Kidney ; Pancreas ; Rejection ; Transplant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Il a été mis au point une méthode de laboratoire pour l'allogreffe pancréatico-duodénale chez le chien pancréatectomisé. Les animaux chez lesquels de telles greffes ont été pratiquées ont survecu plusieurs mois, si on les a traités avec azathioprine et prednisone afin de prévenir le rejet. Contrairement à ce que l'on pense généralement, le pancréas n'est pas particulièrement sensible à l'ischémie totale, étant donné qu'il y a été possible de conserverin vitro jusqu'à 24 heures d'allogreffes pancréatico-duodénales, en employant uniquement l'hypothermie et l'hyperbarie. Ces blocs pancréatico-duodénaux conservés ont été en suite allograffés chez des chiens pancréatectomisés, en obtenant la survie des animaux durant de longues périodes. Nous venons de pratiquer une allogreffe pancréatico-duodénale chez des malades avec diabète juvénile et insuffisance rénale. Parmi ces sujets, 9 ont reçu en même temps une allogreffe rénale prélevée du cadavre. Chez tous ces patients, sauf un, le pancréas a fonctionné immédiatement. Cette exception est représentée par un sujet qui a reçu une allogreffe pancréatico-duodénale prélevée du cadavre après avoir subi une ischémie irréversible. Bien que deux patients seulement soient actuellement en vie (maximum depuis onze mois), nous n'avons jamais observé de signes de rejet du pancréas. Dans 7 cas sur 8 la morte était due à complications en rapport avec l'allogreffe rénale de cadavre, tandis que chez un patient seulement l'allogreffe pancréatico-duodénale était la cause du décès. Ce malade est mort sept mois après l'intervention à cause d'une perforation aiguë du duodénum greffé. De ces recherches il résulte évident que l'antigénicité du pancréas est très inférieure à celle du rein et probablement à celle de bien d'autres organes. L'allogreffe pancréatico-duodénale isolée est actuellement projetée pour les diabétiques juvéniles avec néphropathie grave mais non terminale. Si la vasculopathie caractéristique du diabète sera modifiée par une allogreffe de pancréas, cela deviendra alors une procédure de transplantation d'exécution courante.
    Abstract: Resumen Se ha preparado en el ámbito experimental de laboratorio un procedimiento de alotrasplante pancreático-duodenal en perros operados de pancreactomía. Los perros sometidos a trasplante, y tratados después con azatioprina y prednisón para prevenir el rechazo, sobrevivieron durante muchos meses. Al revés de lo que habitualmente se opina, el pancreas no es particularmente sensible a la isquemia total, puesto que ha sido posible conservarin vitro hasta 24 horas un alotrasplante pancreático-duodenal empleando solamente la hipotermia y hiperbaria. Esos bloques pancreático-duodenales conservados, han sido después alotrasplantados en perros operados de pancreactomía consiguiendo la supervivencia de los perros durante largos periodos de tiempo. Hemos efectuado también un alotrasplante pancreático-duodenal en diez pacientes con diabetes juvenil e insuficiencia renal. Nueve de esos pacientes recibieron simultaneamente un alotrasplante renal extraido del mismo cadáver. En todos estos pacientes, menos en uno, el pancreas ha funcionado inmediatamente. La mencionada excepción la constituye un paciente que recibió un alotrasplante pancreático-duodenal procedente de un cadáver, después de haber sufrido una isquemia irreversible. Aunque solamente dos de los mencionados pacientes sigan con vida, todo lo más a los once meses, en ningún caso hemos advertido indicios de rechazo del pancreas. En siete casos de cada ocho la muerte se debió a complicaciones relacionadas con el alotrasplante renal de cadáver y sólo en uno la causa de la muerte se debió al alotrasplante pancreático-duodenal por una perforación aguda del duodeno trasplantado. De estas investigaciones se deduce con evidencia que la antigenicidad del páncreas es mucho menor que la del riñón y probablemente menor también que la de otros órganos. En la actualidad se proyecta el solo alotrasplante pancreático-duodenal para diabéticos juveniles, con nefropatía grave pero no terminal. Si la vasculopatía característica de la diabetes mellitus será modificada por el alotrasplante pancréatico, este último se convertirá en uno de los procedimientos de trasplante de ejecución más común.
    Notes: Riassunto È stato messo a punto in laboratorio un procedimento per l'allotrapianto pancreatico-duodenale nel cane pancreatectomizzato. I cani nei quali sono stati praticati questi trapianti sono sopravvissuti per molti mesi, se trattati con azatioprina e prednisone per prevenire il rigetto. Contrariamente a quanto abitualmente si ritiene, il pancreas non è particolarmente sensibile all'ischemia totale, dato che è stato possibile conservarein vitro fino a 24 ore un allotrapianto pancreatico-duodenale impiegando solamente l'ipotermia e l'iperbaria. Questi blocchi pancreatico-duodenali conservati sono stati poi allotrapiantati in cani pancreatectomizzati, ottenendo la sopravvivenza degli animali per lunghi periodi di tempo. Finora abbiamo effettuato allotrapianti pancreatico-duodenali in dieci pazienti con diabete giovanile ed insufficienza renale. Nove di questi pazienti hanno ricevuto contemporaneamente un allotrapianto renale prelevato dal medesimo cadavere. In tutti questi pazienti, tranne in uno, il pancreas ha funzionato immediatamente. Questa eccezione è rappresentata da un paziente che ricevette un allotrapianto pancreatico-duodenale da cadavere dopo aver subìto una ischemia irreversibile. Sebbene soltanto due pazienti siano attualmente in vita — uno da undici mesi —, in nessun caso abbiamo riscontrato segni di rigetto del pancreas. In sette casi su otto la morte era dovuta a complicazioni legate all'allotrapianto renale di cadavere, mentre in un paziente soltanto l'allotrapianto pancreatico-duodenale era la causa del decesso. Questo paziente morì, sette mesi dopo l'allotrapianto pancreatico-duodenale, per perforazione acuta del duodeno trapiantato. Risulta evidente da queste ricerche che l'antigenicità del pancreas è di gran lunga minore di quella del rene e, probabilmente, anche di altri organi. Il solo allotrapianto pancreatico-duodenale viene ora progettato per pazienti con diabete giovanile e nefropatia grave non in stadio terminale. Se la caratteristica vasculopatia del diabete mellito risulterà modificata per effetto dell'allotrapianto pancreatico, questo diverrà allora uno dei procedimenti di trapianto di più comune esecuzione.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome analysis of 53 specimens from a population of Gobius fallax has revealed inter- and intra-individual variation in the diploid number (2n=38–43) arising mainly through Robertsonian translocations. The presence of a small biarmed chromosome in a few cells from 3 males as well as the numerous multivalent configurations in meiotic plates and the apparent association between the NOR-chromosomes and other acrocentrics suggest that this polymorphism has an inherited as well as a somatic origin and that some translocations may involve more than two acrocentric pairs simultaneously.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 97 (1987), S. 9-16 
    ISSN: 1573-0832
    Keywords: rhinosporidiosis ; fluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Rhinosporidiosis is reviewed, and the first autochthonous case in Spain is presented (site: in the nasal cavity of a 19-year-old male from a rural background). Diagnosis was established morphologically after eliminating the possibilities of Cryptococcus neoformans, Coccidioides immitis, and Chrysosporium crescens. Clinico-pathological features are described. Preparations were stained with hematoxylin-eosin, PAS, and methenamine silver, and studied for fluorescence. Certain aspects of the epidemiology and diagnosis are commented upon.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Origins of life and evolution of the biospheres 19 (1989), S. 458-459 
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 39 (1988), S. 364-369 
    ISSN: 0947-5117
    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: Repassivierungsfähigkeit von keramikbeschichteten EdelstahlprothesenDas Durchbruchs- und das Repassivierungspotential von keramikbeschichteten Prothesen aus nicht rostendem Stahl sind in Hanks-Lösung und an Implantaten an Hunden bestimmt worden. Diese Werkstoffe zeigen geringe Lochkorrosionsempfindlichkeit und starke Repassivierungsfähigkeit. Der Einfluß von Oberflächenrauhigkeit, Tauchzeit und der Homogenisierungsbehandlung auf das Lochfraßverhalten wird diskutiert.
    Notes: The breakdown and repassivation potentials of stainless steel-ceramic prostheses have been determined both in a Hanks' solution and in implants in dogs. These materials show low susceptibility to pitting corrosion as well as a high repassivation capability. The influence of surface roughness, exposure time and homogenization treatment on the pitting corrosion behaviour is studied.
    Additional Material: 8 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 37 (1986), S. 451-456 
    ISSN: 0947-5117
    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: Zuverlässigkeit elektrochemischer Methoden bei der Untersuchung von Prothesen aus nichtrostendem Stahl mit AluminiumoxidüberzugIm vorliegenden Bericht wird die Korrosionsbeständigkeit von Prothesen aus nichtrostendem Stahl mit Aluminiumoxidüberzug erörtert; als Versuchsmaterial dienten Stahl AISI 316 L mit plasmagespritztem Aluminiumoxidüberzug (mit und ohne Nickel als Zwischenschicht).Die Nickelschicht soll die Haftung zwischen dem keramischen Material und dem Stahl gewährleisten. Als Prüfmedium diente die Hank'sche Lösung, da diese Ähnlichkeit mit organischen Flüssigkeiten aufweist. Zur Verbesserung der Aussagefähigkeit der Ergebnisse wird empfohlen, mehrere der nachstehenden elektrochemischen Methoden nebeneinander zu verwenden: Bestimmung der Zeitabhängigkeit des Korrosionspotentials; Polarisationswiderstandsmessung; coulostatische Methoden und Wechselstrommethoden. Bei der elektrochemischen Untersuchung von keramikbeschichtetem nichtrostendem Stahl im passiven Zustand ergeben sich einige spezifische Schwierigkeiten durch die Störung der Arbeitselektrode infolge der einwirkenden elektrischen Signale, wodurch die Genauigkeit der Korrosionsgeschwindigkeitsmessung beeinträchtigt wird. Diese Schwierigkeiten treten nicht auf, wenn eine Kombination mit einer aktiveren Zwischenschicht benutzt wird.
    Notes: The corrosion resistance of alumina-covered stainless steel prosthesis is discussed in this report. The test material was an AISI 316L steel with a plasma sprayed on alumina coating, applied directly or through an intermediate nickel base layer, whose mission is to guarantee a perfect adherence between the ceramic material and the steel. Use was made in the laboratory of Hank's solution as test medium since this solution is similar to organic fluids. In order to increase the reliability of the results the simultaneous use of various of the following electrochemical methods are recommended: Determination of corrosion potential with the time, polarization resistance method, coulostatic method and a.c. methods. The use of electrochemical methods to study ceramic-covered stainless steel in the passive state poses some specific difficulties accruing from the disturbance of the working electrode by the applied electrical signals which limit the accuracy of the corrosion rate measurements. These difficulties do not appear in the case of a material having a intermediate layer which is more active.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 40 (1989), S. 668-673 
    ISSN: 0947-5117
    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: Umweltfaktoren als Ursache der ungewöhnlichen Korrosion von verzinktem StahlEine ungewöhnlich starke Korrosion von feuerverzinktem Stahl in einer subtropischen Meeresatmosphäre wurde untersucht. Aufgrund der mittels Röntgenbeugungsanalyse der Korrosionsprodukte, des umgebenden Bodens und des aus der Luft abgelagerten Staubs sowie aufgrund der REM-Befunde und der EDAX-Analyse der losen Deckschicht sowie aufgrund der metallographischen Untersuchung von Schnitten durch verzinkten Stahl mit unterschiedlichem Korrosionsgrad wird ein Mechanismus für den Angriff vorgeschlagen, der die außerordentlich hohe Korrosionsgeschwindigkeit des verzinkten Stahls auf die dort herrschenden speziellen atmosphärischen Verhältnisse zurückführt.
    Notes: A phenomenon of unusual heavy corrosion of hot dip galvanized structural steelwork in a subtropical severe marine atmosphere has been studied. Through the data optained from X-ray diffraction analysis of corrosion products, surrounding soil samples and environmental dust samples, and from SEM observations and EDAX analysis of loose corrosion scale, as well as from the information provided by the metallographic study of galvanized steel sections with different degree of corrosion, a mechanism of attack has been proposed, which accounts for the special environmental factors prevailing on the place.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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