Röntgenfluoreszenzspektrometrische Bestimmung des Schwefels in festen und flüssigen Brennstoffen

Anwendungsbereich der genormten Verfahren. Röntgenfluoreszenzspektrometrische Bestimmung des Gesamtschwefelgehaltes in Heizöl, Kohle und Koks. Untersuchungsbedingungen, Standardabweichungen und Zeitaufwand des Verfahrens. Einfluß der Bindungsform des Schwefels in Kohle auf das Meßergebnis.     

Improving the outcome of bone marrow transplantation by using CD52 monoclonal antibodies to prevent graft-versus-host disease and graft rejection

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity after allogeneic bone marrow transplantation, but can be avoided by removing T lymphocytes from the donor bone marrow. However, T-cell depletion increases the risk of graft rejection. This study examined the use of CD52 monoclonal antibodies to eliminate T cells from both donor marrow and recipient to prevent both GVHD and rejection. Seventy patients receiving HLA-identical sibling transplants for acute myelogenous leukemia (AML) in first remission were studied. An IgM (CAMPATH-1M) was used for in vitro depletion of the graft and an IgG (CAMPATH-1G) for in vivo depletion of the recipient before graft infusion. No posttransplant immunosuppression was given. Results were compared with two control groups: (1) 50 patients who received bone marrow depleted with CAMPATH-1M, but no CAMPATH-1G in vivo; and (2) 459 patients reported to the International Bone Marrow Transplant Registry (IBMTR) who received nondepleted grafts and conventional GVHD prophylaxis with cyclosporin A (CyA) and methotrexate (MTX). The incidence of acute GVHD was 4% in the treatment group compared with 35% in the CyA/MTX group (P <.001). Chronic GVHD was also exceptionally low in the treatment group (3% v 36%; P <.001). The problem of graft rejection, which had been frequent in the historic CAMPATH-1M group (31%), was largely overcome in the treatment group (6%). Thus, transplant-related mortality of the treatment group (15% at 5 years) was lower than for the CyA/MTX group (26%; P =.04). There was little difference in the risk of leukemia relapse between the treatment group (30% at 5 years) and the CyA/MTX group (29%). Survival of the treatment group at 6 months was better than the CyA/MTX group (92% v 78%), although at 5 years the difference was not significant (62% v 58%) and neither was the difference in leukemia-free survival (60% v 52%). We conclude that T-cell depletion is a useful strategy to prevent GVHD, provided that measures are taken to ensure engraftment. Using CAMPATH-1G to deplete residual host lymphocytes is a simple and practical method to do this. At least in AML, the beneficial reduction in GVHD can be achieved without an increased risk of relapse.     

Prevention of diabetes but not insulitis in NOD mice injected with antibody to CD4

Non-obese diabetic (NOD) mice were injected with a rat monoclonal antibody to CD4 from birth every two weeks through 6 months of age. These animals gained weight normally but < 11% of their spleen T cells were CD4+, compared with 28% of CD4+ in controls injected with polyclonal rat IgG. The reduction in CD4 cell percentage was associated with a reduction in the number of cells in the thymus and spleen following the injection. CD4+ cells which survived the injections were nevertheless able to enter cell cycle when stimulated by Con A. None of the CD4-treated NOD mice became diabetic by 6 months of age and none of the animals studied histologically at this time had insulitis. At 9 months of age (three months after stopping the CD4 injections) the mice made antibody to human IgG. At 1 year of age most of the male mice had insulitis, although none of the male or female mice had become spontaneously diabetic. Two thirds of animals injected with cyclophosphamide at 16 months became diabetic within 3 weeks. The results confirm that treatment with CD4 antibody in the first 6 months suffices to reduce the incidence of diabetes in NOD mice. The treatment does not prevent the subsequent development of insulitis in injected mice and does not prevent the accumulation of cells capable of causing overt diabetes after cyclophosphamide injection.     

Desaktivierung von technischen Silber-Trägerkatalysatoren für die Herstellung von Ethylenoxid

Deactivation of industrial supported silver catalysts for ethylene oxide production. In view of the model character of the reaction and the unique nature of the catalyst system, it is of interest to study the deactivation behaviour of technical supported silver catalysts for the production of ethylene oxide. In the present study the influence of the catalyst components support, silver, promoter and inhibitor upon the deactivation behaviour is described. The results of chemical, physical and technical investigations of various catalysts and catalyst components are presented. The investigations show that a decrease in the surface area of the exposed silver and increased deposition of chloride are responsible for catalyst deactivation. The possible influence of alkali promoters is discussed and modifications to the catalyst which have been described in the literature as influencing the deactivation are also evaluated.     

Die Analysenfabrik – eine Generation von zukunftsorientierten Eisenhüttenlaboratorien

Ausgehend vom Selbstverständnis eines Eisenhüttenlaboratoriums und dessen Prüfwerten als Dienstleistungsprodukt, werden die Rationalisierungsbemühungen einer Projektgruppe über Reorganisation, Mechanisierung, elektronische Datenverarbeitung und Motivation der Mitarbeiter beschrieben. Die Erfolge zeigen sich in Leistung, Kosten und Personal. Die ?Analysenfabrik“ hat sich bewährt und ist auch für die Aufgaben der Zukunft gerüstet.     

Comparison of several fatigue crack propagation laws with experimental results

The accuracy of several crack propagation equations published in recent years are tested on crack propagation behaviour of fourteen metallic materials. Some equations cannot be verified because they contain unknown material parameters. Four equations based on different crack propagation models yield reasonably good approximations of measured behaviour.     

Klärung der Aufgabe und logische Wirkzusammenhänge beim systematischen Projektieren und Konstruieren

Einteilung technischer Systeme. Hauptschritte und Vorgehen bei systematischer Arbeitsweise. Aufgabenklärung. Wirkzusammenhänge. Logische Wirkzusammenhänge. Logische Funktionen.     

Crack propagation in AlZnMgCu 0.5 during static loading

Fatigue cracked bend specimens of the age hardened aluminum alloy AlZnMgCu 0.5 were investigated in interrupted static load tests. The purpose of the work described in the present paper was to get some informations about the behaviour of cracks under static loads. The fractographic observations showed that crack propagation due to static loads can be divided into two stages, namely initial crack propagation by minute amounts during the blunting of the crack tip and crack propagation due to dimple formation. Both stages of crack propagation can be described quantitatively by simple models. In addition, the stress intensity at the onset of the second crack propagation stage and the plane strain crack toughness can be predicted quite accurately.