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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 84 (1962), S. 4599-4600 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InxGa1−xAs layers (0≤x≤0.37) doped with carbon (〉1020 cm−3) were grown on semi-insulating GaAs substrates by chemical beam epitaxy using carbon tetrabromide (CBr4) as the dopant source. Hall measurements imply that all of the carbon was present as CAs for values of x up to 0.15. The C acceptors were passivated by exposing samples to a radio frequency hydrogen plasma for periods of up to 6 h. The nearest-neighbor bonding configurations of CAs were investigated by studying the nondegenerate antisymmetric hydrogen stretch mode (A−1 symmetry) and the symmetric XH mode (A+1 symmetry) of the H–CAs pairs using IR absorption and Raman scattering, respectively. Observed modes at 2635 and 450 cm−1 had been assigned to passivated Ga4CAs clusters. New modes at 2550 and 430 cm−1 increased in strength with increasing values of x and are assigned to passivated InGa3CAs clusters. These results were compared with ab initio local density functional theory. Modes due to AlInGaCAs clusters were detected in samples containing grown in Al and In. These results demonstrate that for InGaAs, CBr4 is an efficient C doping source since both In–CAs bonds as well as Ga–CAs bonds are formed, whereas there is no evidence for the formation of In–CAs bonds in samples doped with C derived from trimethylgallium or solid sources. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Contact dermatitis 50 (2004), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A large number of monoterpenes and their degradation products are likely skin sensitizing agents (Hausen et al., 1999). Terpenes are very common e.g., as constituents of cosmetics, food and other daily used products.We investigated responses to the endoperoxide 1,4-epidioxy-2-p-menthen (ascaridol), an autoxidation product of tea tree oil, using monocyte derived dendritic cells (MDDC). Therefore, we isolated peripheral blood mononuclear cells (PBMC) from 9 healthy donors by the standard Ficoll-Paque gradient centrifugation.Monocytes were isolated by adherence and incubated in media (RPMI 1640) containing GM-CSF (800 units/ml), IL-4 (1000 units/ml) and 10% autologous serum. The immature MDDC (day 6) were characterized by flow cytometry (CD1a+, CD14−, CD40, CD45, CD80, CD83, CD86, HLA-DR and CCR-7) and incubated with various concentrations of ascaridol (1–70 μg/ml). After one hour incubation time LPS was added (1 μg/ml) for 23 h. Cell culture supernatants were collected after 24 h for cytokine analysis.IL-12p40, IL-12p70 and prostaglandin E2 were measured by ELISA, TNF-alpha and IL-2 were measured by flow cytometry (FACS). Methods of the quantification of steady state mRNA levels were established for IL-12 and CCR7 (real-time RT-PCR). Ascaridol enhanced significantly IL-12p70 production (120% up to 396%) by MDDC as well as mRNA levels for IL-12 and CCR7. Moreover, we detected a distinct increase of TNF-alpha (110% up to 146%) secretion, IL-2 (135%) and PGE2 (102% up to 155%).Totally, these results suggest that ascaridol may be a potent modulator of maturation and antigen presenting function of dendritic cells, and we performing further experiments to verify this hypothesis.This study was supported by the Deutsche Forschungsgemeinschaft.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Contact dermatitis 50 (2004), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Allergic reactions to arylamine dyes are well-known causes for allergic contact dermatitis (ACD). These compounds are found in synthetic and natural materials, hair dyes, sun screen, photographic additives as well as temporary tattoos. Cross-reactions between different para-compounds have been frequently observed but the underlying mechanisms are not fully elucidated. We investigated the immunogenic capacities of p-phenylendiamine (PPD), Bandrowski’s base (BB), 2-methyl-1,4-phenylendiammoniumsulfat (PTD), 4-aminoazobenzene (AAB), disperse orange (DO), disperse yellow (DY), 4–4-diaminophenylmethan (DDM), bismarckbrown (BBY) and 2-mercaptobenzothiazole (MBT) by measuring the proliferative responses of T-cells on polyclonal and monoclonal level (thymidine incorporation). T cell responses were based on CD4+ and CD8+ T cells. Recently, we characterized PPD/BB T cell clones (TCC) as predominantly CD4+/CD45RO+ cells with a alpha/beta T cell receptor (Sieben et al., 2002). We isolated T cell lines (TCL, n = 16) and T cell clones (TCC, n = 20) from totally 11 PPD-allergic persons and 5 exposed persons. We established TCLs and TCCs to 4 para-amino compounds. We found some PPD and/or BB specific TCCs with no cross-reactivity to the other compounds tested. Some TCCs showed a narrow range of cross-reactions (BB, BBY, MBT), while others reacted to 6 different para-amino compounds. We observed similiar patterns of crossreaction for the TCLs. The stimulation indices (SI) varied between 2.2 and 14.0. Our preliminary results on cross-reactions between para-amino compounds support recent findings in mice (Wulferink et al., 2002) demonstrating a limited discriminatory capacity of T cells carrying an alpha/beta T cell receptor. Further studies on the mechanisms of cross-reactivities and the cytokine profiles are now under investigation. This study was supported by the Interdiciplinary Center for Clinical Research and Biomaterials (IZKF, Germany) and the Deutsche Forschungsgemeinschaft (Germany).
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Para-phenylenediamine (PPD), an arylamine dye, is a strong allergen causing allergic contact dermatitis. Cytokines such as TNF-α and IL-1beta are key mediators in the initiation of this reaction. Both cytokines are predominantly produced by stimulated monocytes and macroghages. We investigated the responses of PPD and Bandrowski's base (BB), an autoxidation product of PPD in human monocytes. We isolated monocytes from healthy volunteers and incubated them with the allergens. TNF-α and IL-1beta mRNA expression and protein levels were estimated after 45 min, 2 h, 4 h and 24 h after allergen contact. IL-1beta and TNF-alpha were measured in cell culture supernatants by ELISA (n = 7) and mRNA expression was determined by real-time RT-PCR. We found that PPD reduced TNF-α protein secretion by 20–69.9%(n = 6). Further, IL-1beta levels were decreased by 44–98%. The same tendency was found studying IL-1beta and TNF-α mRNA steady state levels (n = 3; 1 h incubation). These effects were substance-specific and not found for PPD derivatives nor for the autoxidation product BB. These findings suggest that PPD may specifically modify immune responses by directly infering with the cellular proinflammatory cytokine network.This study was supported by the EU.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 51 (1995), S. 1784-1788 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 47 (1991), S. 871-872 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Computers and Education 12 (1988), S. 289-300 
    ISSN: 0360-1315
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Education
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Computers and Education 8 (1984), S. 305-316 
    ISSN: 0360-1315
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Education
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary 4-Fluoro- and 4,4′-difluorostilbene are similar in their reactivities towards the benzoyloxy radical; a similar conclusion has been reached in respect of 4-chloro- with 4,4′-dichlorostilbene and 4-phenyl-with 4,4′-diphenylstilbene. These results have been obtained by consideration of the numbers of benzoate and phenyl end-groups in poly (methyl methacrylate) made using benzoyl peroxide in the presence of the appropriate derivative of stilbene.
    Type of Medium: Electronic Resource
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