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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of paleolimnology 9 (1993), S. 161-178 
    ISSN: 1573-0417
    Keywords: 210Pb dating ; geochronology ; sedimentation rates ; 137Cs ; Switzerland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract We present a historical overview of applications of210Pb dating in Switzerland with a special emphasis on the work performed at the University of Bern. It is demonstrated that the average specific activity of210Pb in the lower atmosphere is very constant and does not show seasonal variations. We then concentrate on new results from Lobsigensee, a very small lake, and on published and new data from Lake Zurich. Several210Pb profiles from these lakes show obvious disturbances and a disagreement of the resulting sedimentation rate when compared to that for the 23 years defined by137Cs peaks of 1986 (Chernobyl) and 1963 (bomb fallout). A mean sedimentation rate of about 0.14 g cm−2 y−1 is found in the oxic and suboxic center part of Lake Zurich. In the oxic locations, the210Pb flux to the sediments was close to the atmospheric input of about 1/60 Bq cm−2 y−1. In other parts of the lake a significant deficit in the inventory of210Pb was found in the sediments. This could be due to a chemical redissolution of210Pb together with Mn under reducing conditions. In contrast, in the suboxic part of the lake (135 m depth) the flux of210Pb was about twice the atmospheric input. This excess is not caused by allochthonous contributions and is tentatively explained by the transport of sediment material resulting from small slides at the very steep lake shores or more probably by reprecipitation of210Pb together with Mn when the conditions in the lake water become locally and seasonally more oxidizing. Dissolved210Pb may migrate from locations with reducing conditions and reprecipitate under more oxic conditions. Indeed, a correlation of Mn and210Pb in sediments of Lake Zurich was found.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 41 (1980), S. 347-357 
    ISSN: 1432-0584
    Keywords: Leukocyte transfusion ; Granulocyte substitution ; Granulocyte and ; monocyte function ; Filtrationsleukapherese ; Leukozytentransfusion ; Granulozy-tensubstitution ; Granulozyten- und Monozytenfunktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Filtrationsleukapherese (FL) stellt im Rahmen der Granulozytensubstitution zur Behandlung einer schweren passageren Neutropenie eine effiziente Methode zur Gewinnung adäquater Granulozytenmengen dar. Die Wirksamkeit einer Granulozytentransfusion hängt unter anderem wesentlich vom Funktionszustand der transfundierten Neutrophilen ab. Im Rahmen der repetitiven FL wurde in der vorliegenden Arbeit bei acht hämatologisch gesunden Spendern die Funktion der Neutrophilen und Monozyten im Eluat untersucht und mit den entsprechenden Werten der Zellen im Spenderblut verglichen. Dabei fielen vor allem durch die Prämedikation mit Dexamethason hervorgerufene Veränderungen auf. Die corticosteroidbedingte Ausschüttung des Reservespeichers im Knochenmark bewirkte eine Neutrophilie mit Zunahme der Stabkernigen sowie einen deutlichen Abfall der ALP-Aktivität und der Bakterizidie. Der leichte Anstieg des Latex-Phagozytose-Index während der FL wurde als Zellaktivierung, wahrscheinlich hervorgerufen durch eine Komplementaktivierung im Ablauf des Elutionsprozesses, interpretiert. Eine starke Erhöhung des Latex-Phagozytose-Index im Eluat der Leukopak-Filter reflektiert wohl eine metabolische Folge des Neutrophilenkontaktes mit den Nylonfasern der Filter. Der dadurch aktivierte Degranulationsprozess wurde durch den progredienten Verlust der Bakterizidieleistung bei zunehmender Filtrationsdauer dokumentiert. Die Bakterizidie-Indices des 1,5-h- und 3-h-Eluates aus den Filtern waren jedoch im Vergleich zu den Werten im Spenderblut nicht signifikant verschieden. Durch die Methode der repetitiven FL, welche die Kontaktzeit der Neutrophilen zum Filtermaterial auf ein Minimum beschränkt, scheint die technisch bedingte Degranulation der Granulozyten abgeschwächt und damit die funktionelle Alteration der transfundierten Zellen verringert zu werden. Die durch die Prämedikation induzierten Veränderungen des Blutbildes verursachten durch vermehrtes Auftreten funktionell unreifer Neutrophiler einen geringfügigen Funktionsverlust der Spender-Granulozyten.
    Notes: Summary Filtration leukapheresis (FL) is an effective and economic technique to collect large amounts of neutrophils for substitutional treatment of severe, transient neutropenia. An essential factor for effective granulocyte transfusion is functional integrity of the transfused cells. In this study eight hematologically normal donors were subjected to repetitive-cycle-FL to examine functional changes of the collected neutrophils and monocytes compared to the donor's corresponding blood cells. After conditioning with dexamethasone, increased neutrophil counts, increased percentage of band forms, decreased activity of leukocyte alcaline phosphatase, and decreased bactericidal activity were demonstrated. These changes indicate increased release of functional immature neutrophils of the nonproliferating bone marrow granulocyte pool. An increased latex-phagocytosis-index was noted during FL, signaling a cell stimulation, possibly by complement activation during FL. The marked increase of latex-phagocytosis-indices of the eluted neutrophils was possibly induced by the neutrophils direct contact with the nylon fibers of the filter, resulting in mild degranulation, documented by the progressive but slight loss of bactericidal activity during FL. The indices of bactericidal activity were, however, not significantly different as compared to the values in the donor's blood. The repetitve-cycle-FL with minimal duration of contact between blood cells and nylon fibers of the filter, limits the process of degranulation and thereby technically reduces the functional alteration of donor granulocytes. Pretreatment of the donor with dexamethasone resulted only in a minimal change of functional integrity, caused by a transiently increased release of less mature neutrophils to the donor's blood.
    Type of Medium: Electronic Resource
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