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  • 1
    Electronic Resource
    Electronic Resource
    Nanostructure of thin amorphous hydrogenated carbon films studied by positron annihilation and photoluminescence (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 404-410 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We deposited polymer-like a-C:H films using the plasma-enhanced chemical vapor deposition technique and characterized film microstructure by variable-energy positron lifetime spectroscopy, photoluminescence (PL), and UV-visible absorption spectroscopy. It was confirmed that PL occurs from a chromophore in a sp2 cluster as a result of fast recombination of a photoexcited electron-hole pair. Positron annihilation lifetime spectroscopy showed that positronium (Ps) formation takes place via electron-positron recombination in the sp3 matrix. The lifetime of ortho-positronium (o-Ps) in our a-C:H films was similar to that in polyethylene, indicating their polymer-like nature. The relative PL efficiency increased by about an order of magnitude with increasing film band gap from 1.3 to 3.4 eV, which can be related to the decreasing concentration of nonradiative centers. On the other hand, Ps formation was much less influenced by the band gap and nonradiative centers. Comparison of this result with that for polyethylene mixed with carbon-black nanoparticles, where a considerable reduction in Ps formation was observed, showed that nonradiative centers were of a different nature from the defects on the carbon nanoparticle surface. This work demonstrated the usefulness of positron lifetime spectroscopy combined with optical measurements to study the nanostructure of a-C:H. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1378063
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  • 2
    Electronic Resource
    Electronic Resource
    Nanoporous structure of sputter-deposited silicon oxide films characterized by positronium annihilation spectroscopy (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 1704-1706 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Positronium annihilation was applied to characterize the nanoporous structure of thin silicon oxide films sputter-deposited at different argon pressures ranging from 0.1 to 2.0 Pa. At higher argon pressures, the 3γ decay probability of ortho-positronium (o-Ps) was substantially enhanced. A comparison of this result with that obtained for capped samples indicated that: (a) 3γ annihilation is due to the intrinsic decay of o-Ps diffusing out from the film into vacuum and (b) films deposited at high argon pressures contain highly connected, open pores. Positron lifetime spectroscopy measurements on the capped films showed that the characteristic size of the pores can be as large as 2.6 nm, depending on the argon pressure. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1428787
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  • 3
    Electronic Resource
    Electronic Resource
    Epitaxial growth of LiNbO3-LiTaO3 thin films on Al2O3 (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 2989-2993 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Epitaxial thin films of LiNbO3 and LiTaO3 were grown on sapphire substrates by the rf-magnetron sputtering method. Structural characterization was made by several spectroscopic measurements: x-ray diffraction, Raman scattering, and optical absorption. We obtained epitaxial thin films with lattice-mismatched strained layers, without misfit defects which are usually created at the interface. Impurity-ion (Nd3+ and Cr3+) doped films were also grown; these films had larger refractive indices than the pure films. Furthermore, the heteroepitaxial thin films of up to 10 alternating LiNbO3/LiTaO3 layers were successfully grown, and their periodic structures were studied by optical second-harmonic generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.339385
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  • 4
    Electronic Resource
    Electronic Resource
    Chemical and Histological Characterization of Raw Muscle from Soft and Hard Crabs of Snow Crab Chionoecetes opilio (2001)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 66 (2001), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: : Chemical analysis showed soft snow crab muscle to have a higher water content and a lower protein content than hard crab muscle. Histological observations revealed frequent occurrences of disintegrated regions in muscle fibers and pericellular connective tissue of soft snow crab muscle tissue. Salinity of the free body fluid recovered from the meropodites of the soft snow crab was significantly higher than that of the hard snow crab. Sensory evaluation revealed differences in texture and taste between soft and hard crabs, which corresponded well to their compositional and histological differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2001.tb11324.x
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  • 5
    Electronic Resource
    Electronic Resource
    Free volume and physical aging of poly(vinyl acetate) studied by positron annihilation (1989)
    s.l. : American Chemical Society
    Macromolecules 22 (1989), S. 2302-2306 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00195a052
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation and properties of III-V nitride thin films (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 2984-2988 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thin films of III-V nitride semiconductors (AlN, GaN, InN), mixed-crystalline films (AlxIn1−xN), and multilayered films (GaN/InN)n were grown by rf magnetron sputtering at low substrate temperatures below 500 °C. These films were characterized by x-ray diffraction, Raman scattering, optical absorption, and electrical measurements; it was proved that they have high crystal quality comparable to the previously reported data obtained by other growth methods. Dependence of the band-gap energy of AlxIn1−xN on composition x was determined. Multilayered films of (GaN/InN) were prepared for the first time; these films showed the characteristic diffusion property to make an ordered-alloy superlattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344181
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  • 7
    Electronic Resource
    Electronic Resource
    Novel dinucleotide repeat polymorphism in the first exon of the STAT-6 gene is associated with allergic diseases (2001)
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 31 (2001), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background T helper-type 2 cytokines, such as interleukin-4 (IL-4) and IL-13, may play a central role in allergic diseases. The protein known as ‘signal transducers and activators of transcription 6’ (STAT-6) is a key transcription factor involved in both IL-4- and IL-13-mediated biological responses.Objective The objective of this study was to evaluate the possible role of the STAT-6 gene in modulating atopy in the Japanese population.Methods We screened all 23 exons of the STAT-6 gene from 10 subjects for mutations by direct polymerase chain reaction (PCR) sequencing. The STAT-6 gene polymorphisms were genotyped by PCR fragment length polymorphism analysis and PCR-SSCP analysis. The IL-4 receptor Q576R polymorphism was also examined by PCR-SSCP analysis.Results We found a novel dinucleotide repeat polymorphism in the first exon of the STAT-6 gene. The genotypes were classified into four groups according to the number of GT repeats present, from 13 to 16. The frequency of the A1 allele (326 bp, containing 13 repeats of GT) was higher in children with allergic diseases (bronchial asthma, atopic dermatitis and/or food-related anaphylaxis) than controls, although this was not statistically significant (P = 0.0158). In addition, a strong association between the A1 and A3 allele (containing 15 repeats of GT) heterozygote and allergic diseases was identified (P = 0.0002). However, the levels of IgE were not related to the GT repeat polymorphism in the allergic subjects. The GT repeat polymorphism was not associated with the polymorphism in the IL-4 receptorachain gene (Q576R) and there was no association between the G2964A variant and allergic diseases.Conclusion This suggests that genetic variation in the STAT-6 gene may be associated with predisposition to allergic diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2222.2001.01191.x
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  • 8
    Electronic Resource
    Electronic Resource
    Increased serum nitrate levels in infants with atopic dermatitis (2001)
    Copenhagen : Munksgaard International Publishers
    Allergy 56 (2001), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: The pathogenesis of atopic dermatitis (AD) is still unknown. A recent study has shown that inducible nitric oxide synthase (iNOS) is expressed in the atopic skin lesion, suggesting the involvement of nitric oxide in the skin inflammation of AD. The purpose of the study was to examine serum nitrate (NO3) levels in relation to the disease severity in children with AD. Methods: Serum nitrate levels were assessed in relation to the skin scores in 88 patients with atopic dermatitis (AD) (aged 0.4–8 years: mean±SD, 2.2±1.9, 41 boys and 47 girls) and 12 nonatopic children (aged 0.8–4 years: mean±SD, 1.8±0.9, seven boys and five girls). Results: Serum nitrate levels of patients with AD were significantly increased as compared to nonatopic controls and were also correlated with the disease severity. The skin scores were significantly correlated with serum nitrate levels as well as peripheral eosinophil counts. Conclusions: Our results indicate that nitric oxide may be involved in the pathogenesis of vasodilation and erythema in AD skin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1398-9995.2001.00131.x
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  • 9
    Electronic Resource
    Electronic Resource
    Long-term effect of 2-year steroid therapy in progressive IgA nephropathy: A 30-year follow-up study compared with a non-steroid group (2003)
    Melbourne, Australia : Blackwell Science Pty
    Nephrology 8 (2003), S. 0 
    Details
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1797.2003.00198.x
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  • 10
    Electronic Resource
    Electronic Resource
    Long-term prognosis of 366 IgA nephropathy patients (2002)
    Melbourne, Australia : Blackwell Science Pty
    Nephrology 7 (2002), S. 0 
    Details
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1797.7.s.38.x
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