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  • 1
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The suitability of PVD films of γ-Al2O3 and of ternary Al-O-N as diffusion barriers between a nickel based superalloy CMSX-4 and NiCoCrAlY for a possible application in gas turbines was investigated. Therefore, an Al2O3 film and, alternatively, an Al-O-N film were deposited on CMSX-4 at 100 °C substrate temperature by means of reactive magnetron sputtering ion plating (MSIP). After characterization of composition and structure of the films by X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (XRD), a NiCoCrAlY coating was deposited onto the diffusion barriers and, for comparison, directly onto CMSX-4 by MSIP as well. The composites were annealed for 4 h at 1100 °C under inert atmosphere. Wavelength dispersive X-ray (WDX) element mappings and line-scans of the cross-sectional cut served to evaluate the suitability of the films as diffusion barriers. After detachment of the coatings from the substrate, the phase stabilities of the two metastable phases γ-Al2O3 and Al-O-N were determined by means of grazing incidence XRD. Without a diffusion barrier, enhanced interdiffusion was observed. Analyses of the composite with the γ-Al2O3 interlayer revealed diffusion of Ti and Ta from the substrate into the NiCoCrAlY coating. No interdiffusion of Ni, Ti, Ta, and Cr could be detected in case of the ternary Al-O-N film. Whereas the ternary Al-O-N film remained in the as-deposited X-ray amorphous structure after annealing, a phase change from the γ to the α modification could be observed in case of the Al2O3 film, presumably responsible for its lower efficiency as a diffusion barrier.
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  • 2
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Homogeneous films of metastable Cu3N were deposited on Si-〈100〉 wafers at 90° C by means of reactive magnetron sputtering ion plating. Under electron bombardment with a focused beam at high current (〉 700 nA, 15 keV) these films transform into metallic Cu and N2. The depletion of N was measured quantitatively by EPMA. Structures with a lateral size of 2 μm consisting of metallic copper were written into the Cu3N films. AFM surface scans revealed a vertical growth of the columnar grains of the Cu3N film due to the electron bombardment.
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  • 3
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Structural transitions of metastable Ti1–xAlxN coatings on technically relevant substrates were determined as a function of the Ti/Al ratio. Ti1–xAlxN films with different Ti/Al ratios were deposited on high speed steel (HSS) substrates at substrate temperatures of 300 ° and 500 °C by means of reactive magnetron sputtering ion plating (MSIP). A Ti/Al compound target was used as well as a cluster arrangement of one Ti and one Al target for comparison. The composition of the films was determined by electron probe microanalysis (EPMA), the crystallographic structure by thin film X-ray diffraction (XRD). The analyses revealed that films deposited with Ti/Al ratios of 44/56 and 36/64 had grown in cubic NaCl structure, a film with a Ti/Al ratio of 32/68 was two-phase, and a Ti/Al ratio of 25/75 led to a hexagonal film in wurtzite structure. Only small differences of the lattice parameters could be observed in dependence of temperature: At 300 °C the lattice parameters of the cubic structure corresponded exactly to Vegard‘s law, whereas they slightly decreased in the films deposited at 500 °C. The application of a cluster arrangement instead of a compound target resulted in nearly the same lattice parameters and peak shapes.
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  • 4
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Due to its high surface sensitivity, electron spectroscopy has proven to be a powerful tool for the determination of binding states and electronic structures of thin films. The principal processes of electrons and photons interacting with a surface are briefly discussed. Special attention is paid to the determination of binding states, near range orders and the electronic structures in ceramics by Auger- and Photoelectron Spectroscopy (AES and XPS) as well as Electron Energy Loss Spectroscopy (EELS). The particularities of electron spectroscopy of metastable ternary ceramic solution phases which have been deposited by means of reactive magnetron sputtering are described. Because of their continuous change in composition and, thus, in chemical environment, these solution phases are attractive systems for the analysis of the effects of chemical environment upon binding states and the electronic structure of ceramics.
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  • 5
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 6
    ISSN: 1432-1076
    Keywords: Key words Latex allergy ; Spina bifida ; Fruit allergy ; Atopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Type 1 allergy against natural rubber latex is an increasing problem in health care workers and children with spina bifida or urogenital malformations. The aim of our study was to evaluate the prevalence of latex IgE antibodies and cross-reacting fruit antibodies in patients with spina bifida compared with atopic and non-atopic controls. Risk factors for sensitization should be determined. Sera of 148 patients with spina bifida and 98 controls (44 with atopy) were screened for IgE antibodies against latex, banana and kiwi by fluorescence enzyme immunoassay (CAP system). Atopies, allergic symptoms after latex contacts and the number of operations were compiled by a questionnaire. Patients with spina bifida developed latex IgE antibodies (≥0.7 kU/l) more frequently (40.5%) than atopic children (11.4%) or healthy controls (1.9%). All 18 symptomatic patients belonged to the spina bifida group and had high values of latex antibodies. The risk for developing latex antibodies increases with the number of operations. There was no difference in the history of atopic diseases and in a screening test of IgE antibodies against inhalative allergens between latex sensitized and not sensitized children with spina bifida. Antibodies against banana were more frequent in the latex sensitized children with spina bifida. (18.3% vs 3.4%, P = 0.002). Conclusion The high prevalence of latex antibodies in children with spina bifida justifies a primary prophylaxis by avoiding latex contacts, especially during anaesthesia and surgery, a correlation between the number of operations and the development of latex antibodies exists.
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  • 7
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 8
    ISSN: 1432-1076
    Keywords: Key words Disseminated intra-vascular coagulation ; Limb ischaemia ; Purpura fulminans ; Septic shock ; Skin necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract More than 10% of children surviving septic shock with purpura have skin necrosis or limb ischaemia (SNLI.). Among 44 children consecutively admitted to our pediatric intensive care unit, 35 (80%) survived, 6 of them (17%) developed SNLI (defined as the need of a surgical procedure). Two timed haemostasis measurements included the determination of coagulation factors, protein C (PC), protein S (PS), C4b binding protein (C4bBP), antithrombin (AT), and plasminogen activator inhibitor 1 (PAI-1). Two severity scores and CRP levels were determined at admission. Children with SNLI and without SNLI were compared. On admission, severity scores, and AT, PC, PS, C4bBP levels were similar in both groups with and without SNLI. Prothrombin time (23% vs 34%; P 〈 0.01), factor VII+X (20% vs 31%; P = 0.05) and factor VII (0% vs 19%; P 〈 0.01) were lower in the group with SNLI. The 2nd sample showed no difference between the two groups. Kinetics of haemostatic abnormalities were no different between the two groups. Conclusion In this series, the only difference between the two groups was lower factor VII levels in children with skin necrosis or limb ischaemia. This suggests the benefit of tissue factor pathway inhibitor administration as an adjunctive therapy to prevent skin necrosis or limb ischaemia. Further studies including more children are needed to determine the potential effects of treatments such as protein C, antithrombin, and plasminogen activator inhibitor antibody administration, and to advocate tissue factor pathway inhibitor in preventing skin necrosis or limb ischaemia.
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  • 9
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Williams Beuren-Syndrom ; Nierenarterienstenose ; Renovaskuläre Hypertonie ; Key words Williams-Beuren-syndrom ; Renovascular hypertension ; Renal artery stenosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Patients with Williams-Beuren-Syndrome characterized by the combination of typical morphology, supravalvular aortic stenosis and mental retardation. The typical cardiac malformation, the supravalvular aortic stenosis may be absent. Progressive peripheral vascular lesions as renal artery stenosis, coronary vascular abnormalities and cerebrovascular ischemia were not commonly observed in the past. Case report: We present a 12 year old girl with Williams-Beuren-Syndrome without typical signs of cardiac involvement who developed renovascular hypertension after 9 years of follow up due to stenosis of a renal artery. It was successfully treated by aortorenal bypass. Discussion: In the absence of typical cardiac involvement Patients with Williams-Beuren Syndrome can develop progressive vascular lesions as renal artery stenosis, coronary artery stenosis or cerebro-vascular lesions. Therefore irrespective of cardiac involvement patients with Willliams-Beuren syndrome should be followed up with special regards to this complication.
    Notes: Zusammenfassung Patienten mit Williams-Beuren-Syndrom werden durch die klassischen Symptome der auffälligen Morphologie des Gesichts, der supravalvulären Aortenstenose und der mentalen Retardierung beschrieben. Die klassische kardiale Beteiligung in Form der supravalvulären Aortenstenose kann bei Patienten mit Williams-Beuren-Syndrom fehlen. Unabhängig davon können progressive periphere Gefäßveränderungen bestehen. Diese können z. B. als Nierenarterienstenose, Koronaranomalie oder zerebrovaskuläre Ischämie symptomatisch werden. Fallbericht: Wir berichten über 1 Patientin mit Williams-Beuren-Syndrom ohne die kardiale Veränderung der supravalvulären Aortenstenose, die im Alter von 10 Jahren eine schwere arterielle Hypertonie infolge einer einseitigen Nierenarterienstenose entwickelte. Die Anlage eines aortorenoarterialen Bypasses war eine effektive Behandlung. Diskussion: Auch beim Fehlen der klassischen Symptomen des Williams-Beuren-Syndroms müssen progrediente Gefäßveränderungen rechtzeitig erkannt und als bedeutsame Komplikationen des Krankheitsverlaufs bedacht werden.
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  • 10
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Latexallergie ; Latexproteine ; Kreuzallergene ; HLA-Assoziation ; Prophylaxe ; Key words Latex allergy ; Latex proteins ; Crossreacting fruits ; HLA-association ; Prophylaxis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary During the last ten years better hygienic standards led to an increased use of natural latex gloves for protection of medical staff. During this time reports about an IgE mediated allergy to latex up to life-threatening anaphylactic reactions came up. This allergy was different from the known type IV reactions on latex additives. Health care workers and patients with multiple surgery were identified as high risk groups. For unknown reasons patients with spina bifida show the highest prevalence of latex-specific IgE antibodies. A preexisting atopy increases the risk of latex sensitization. Allergic reactions are caused mainly by medical treatments, especially surgery, when latex gloves and other latex containing articles are used. Allergenic proteins: Meanwhile some allergenic proteins in latex could be identified. Patients in different risk groups showed different prevalences of sensitization to these allergens. The way of allergen uptake (aerogen or by intraoperative direct mucosal contact) may play an important role in sensitization to different allergens. Some allergens like Hev b 1, Hev b 3, Hev b 6.02 habe been totally or partially sequenced; on Hev b 1 molecule several IgE binding epitopes have been localized. T lymphocytes could be estimated by latex proteins. There is an association between the HLA antigens DR4 and DQ8 and the specific IgE response to the latex allergen Hev b 6.02, in contrast no significant association was observed between the IgE response to Hev b 1 and HLA class II alleles. Crossreacting antibodies between latex and numerous tropical fruits are described. For some proteins structural homologies are well characterized. Diagnosis: For the diagnosis of latex allergy serologic tests (for instance the CAP system) are available. Latex protein extracts for skin prick tests are difficult to standardize. Prophylaxis: For high risk patients a primary prophylaxis is recommended, a secondary or tertiary prophylaxis allows safe operations without symptoms of latex allergy.
    Notes: Zusammenfassung Im zeitlichen und wahrscheinlichen auch ursächlichem Zusammenhang mit dem steigenden Verbrauch von Latexhandschuhen wurde neben den schon bekannten Typ-IV-Allergien auf Zusatzstoffe des Latex auch über IgE vermittelte Typ-I-Sofortreaktionen bis zu lebensbedrohlichen anaphylaktischen Reaktionen berichtet. Als besondere Risikogruppen wurden neben medizinischem Personal Patienten mit multiplen Voroperationen identifiziert. Von ihnen haben aus noch nicht näher bekannten Gründen Patienten mit Spina bifida die höchsten Prävalenzen. Eine vorbestehende Atopie erhöht das Risiko der Latexsensibilisierung. Allergische Reaktionen auslösende Situationen sind v. a. bei medizinischen Maßnahmen verschiedenster Art gegeben, in denen Latexhandschuhe und andere Latexartikel verwendet werden. Allergene: Inzwischen konnten mehrere allergene Proeine im Latex identifiziert werden, die in unterschiedlicher Häufigkeit Risikogruppen sensibilisieren, wobei auch der Weg der Allergenaufnahme (aerogen, durch direkten intraoperativen Schleimhautkontakt) eine Rolle spielen dürfte. Einzelne Allergene (z. B. Hev b 1, Hev b 3, Hev b 6.02) wurden ganz oder teilweise sequenziert, für Hev b 1 liegen bereits Analysen der IgE-Bindungsstellen vor. Auch T-Zell-Stimulationsexperimente wurden mit einzelnen Proteinen erfolgreich durchgeführt. Die Assoziation der IgE-Antwort auf Hev b 6.02 mit den HLA-Antigenen DR4 und DQ8 konnte gesichert werden, eine signifikante Assoziation zwischen der IgE-Antwort auf Hev b 1 und dem HLA-System war nicht zu finden. Kreuzreagierende Antikörper sind zwischen Latex und zahlreichen exotischen Früchten beschrieben worden, deren Allergenhomologien z. T. bereits gut charakterisiert sind. Diagnose: Zur Diagnose der Latexallergie stehen z. Z. serologische Tests (z. B. CAP-System) und wenige schwer zu standardisierende Hauttests zur Verfügung. Prophylaxe: Bei Hochrisikopatienten wird erfolgreich eine primäre Prophylaxe angewandt, auch eine sekundäre oder tertiäre Prävention ermöglicht Operationen ohne Symptome der Latexallergie.
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