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  • 1
    Electronic Resource
    Electronic Resource
    Local vibrational modes as a probe of activation process in p-type GaN (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1383-1385 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Raman spectra for a series of Mg-doped GaN films grown by metal organic chemical vapor deposition and annealed in N2 ambiance at different temperatures have been investigated. Some local vibrational modes related to hydrogen were observed, showing drastic changes with the annealing temperature. The spectra show clearly that H impurities incorporated in as-grown films, which passivate Mg acceptors, are released from the Mg–N bonding at above ∼600 °C, and diffuse in the film to form new chemical bondings. We have also observed a local mode related to activated Mg acceptors. This mode is conveniently used as a probe of the activation process of Mg acceptors. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124701
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  • 2
    Electronic Resource
    Electronic Resource
    Raman studies on phonon modes in cubic AlGaN alloy (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 191-193 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Cubic AlxGa1−xN alloy layers have been successfully grown for x=0−1 by gas-source molecular beam epitaxy on cubic-SiC/Si substrates, and the compositional dependence of the transverse-optic (TO) and longitudinal-optic (LO) phonon modes has been studied by Raman scattering. The LO-mode frequency of mixed crystals shows a systematic variation from the pure cubic AlN phase to the cubic GaN phase (one-mode type). On the contrary, there are two branches for the TO mode varying slowly in frequency with the composition (two-mode type). This behavior is explained within a random-element-isodisplacement model including the effect of polarization field. Our result indicates a strong polarization field acting on the cation-nitrogen bonds. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123289
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  • 3
    Electronic Resource
    Electronic Resource
    Extramammary Paget’s disease in two siblings (1999)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 141 (1999), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.1999.03192.x
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  • 4
    Electronic Resource
    Electronic Resource
    XAFS study on EuC60 (1999)
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 6 (1999), S. 779-780 
    Details
    ISSN: 1600-5775
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0909049598016288
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  • 5
    Electronic Resource
    Electronic Resource
    Nestmate recognition in the stingless bee Melipona panamica (Apidae, Meliponini) (1999)
    Springer
    Insectes sociaux 46 (1999), S. 208-218 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Melipona panamica, stingless bees, Apidae, nestmate recognition, worker oviposition.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Nestmate recognition was studied in the Neotropical stingless bee Melipona panamica, a species in which workers “sneak” their own reproductive eggs into 1 % of brood cells. We manipulated four factors that could influence individual recognition cues: the mother queen, the environment during the immature stage, the environment during the early adult stage, and worker age. We also simulated the action of natural enemies on colonies tested for discrimination of such worker characteristics. All factors that we tested affected responses of the discriminating workers, which could recognize sisters, nieces and unrelated workers. Previous exposure of unrelated callow bees to the odor of the host nest greatly increased chances of acceptance by the host colony. Probability of acceptance decreased, however, with increasing age of introduced bees or increasing disturbance of the host colony. These complexities in patterns of nestmate recognition and nest defense are adequately explained from the standpoint of inclusive fitness of the discriminating workers. Differences in nestmate recognition and worker egg laying among Meliponini are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050136
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  • 6
    Electronic Resource
    Electronic Resource
    Calcaneus Bone Mineral Density Using Single X-ray Absorptiometry in Japanese Women (1999)
    Springer
    Calcified tissue international 65 (1999), S. 106-111 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Calcaneus bone mineral density — Osteoporosis — Single X-ray absorptiometry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Calcaneus bone mineral density (BMD) of 738 Japanese women (605 healthy and 133 with osteoporosis) was measured using single X-ray absorptiometry (SXA). A reference range of calcaneus BMD values for healthy Japanese women was established and the usefulness of this method for screening and diagnosis of osteoporosis was evaluated. There was no significant age change of calcaneus BMD prior to menopause, though values decreased significantly thereafter. BMD loss ratio was 1.7%/year in the 10 years after menopause. The reference range of calcaneus BMD was 410 ± 43 mg/cm2, calculated from the mean BMD value of subjects whose ages ranged from 25 to 50 years old. The fracture threshold for the spine was established as 294 mg/cm2, which corresponded to −2.67 SD from the average BMD of the young healthy women, and the odds ratio for spine fracture in the subjects with BMD lower than this threshold was 3.52 [95% CI (confidence interval) 1.34–9.26]. The spine fracture group showed statistically lower calcaneus BMD than the nonfracture group when subjects with adjusted age and body size were analyzed. There were no significant differences in the ROC analysis for spine fracture between calcaneus BMD and spine BMD. Therefore, calcaneus BMD is not readily affected by degenerative change or soft tissue, and the annual decrement rate (1.7%/year) can be detected easily and with low precision error (0.8%). These indices may prove useful for the screening and diagnosis of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900665
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  • 7
    Electronic Resource
    Electronic Resource
    Mg-vacant structural modules and dilution of the symmetry of hydrous wadsleyite, β-Mg2–xSiH2xO4 with 0.00≤x≤0.25 (1999)
    Springer
    Physics and chemistry of minerals 26 (1999), S. 382-388 
    Details
    ISSN: 1432-2021
    Keywords: Key words Hydrous wadsleyite ; Mg-vacant structural modules ; Dilution of symmetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract  The crystal structures of the two hydrous wadsleyite crystals with formulae, Mg1.75SiH0.50O4 (0.5H–β) and Mg1.86SiH0.28O4 (0.3H–β) have been analyzed in this study. The single-crystal X-ray diffraction data showed that the unit cells of the 0.3H–β and the 0.5H–β are metrically monoclinic with a slight distortion from the orthorhombic cell but their intensity distributions conform to the orthorhombic symmetry within the limit of experimental errors. The Fourier and the difference Fourier syntheses were calculated. Small but significant Fourier peaks were found at the site, Si2, in a normally vacant tetrahedral void adjacent to Mg3 site as reported for the monoclinic hydrous wadsleyite by Smyth et al.. From the comparison of the hydrous and anhydrous wadsleyite structures, the Mg-vacant structural modules were found to be the building units for the structure of hydrous wadsleyite. The dilution of symmetry from orthorhombic to monoclinic in the hydrous wadsleyite structure is interpreted qualitatively due to lack of mirror perpendicular to the a axis in the module. The mode of arrangement of the Mg-vacant structural modules interprets the symmetry and hydrogen content of the hydrous wadsleyite and gives the structural relationship between hydrous wadsleyite and hydrous ringwoodite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002690050198
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  • 8
    Electronic Resource
    Electronic Resource
    Fission fragment configurations at the scission point of233U,235U and239Pu(nth,f) (1999)
    Springer
    Journal of radioanalytical and nuclear chemistry 239 (1999), S. 117-122 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In order to estimate the deformation rate of fission fragment at the scission point for thermal neutron-induced fission of233,235U and239Pu, double-velocity and double-energy measurements were carried out. As the result of the estimation of the deformation rate, two types of scission point configurations were found. One type is composed of deformed light and heavy fragments, and the other type is a combination of deformed light and spherical heavy fragments. Mass and total kinetic energy distributions were sorted in two distributions by means of the type of configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349541
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  • 9
    Electronic Resource
    Electronic Resource
    Reaction mechanism for target-like products from197Au target bombarded with12C ions of energies above 100 MeV/u (1999)
    Springer
    Journal of radioanalytical and nuclear chemistry 239 (1999), S. 143-149 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Target-like products, that is,191–200Au,185–200Pt, and183–195Ir, from197Au target bombarded with12C ions at the energies of 180, 230, and 400 MeV/u were measured by using off-line gamma-ray spectrometry combined with chemical separation procedures. Spallation systematics by Rudstam reproduces well the measured cross sections for formation of platinum and iridium isotopes. It was found that the cross sections of gold nuclides increase with increase of the incident energy in the range studied and they are enhanced if compared with the reported proton-induced reaction of gold at a similar incident energy. It is suggested that the electromagnetic dissociation process plays a role for production of such gold nuclides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349546
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of glucocorticoids on bone mineral density in rheumatoid arthritis patients (1999)
    Springer
    Archives of orthopaedic and trauma surgery 119 (1999), S. 18-21 
    Details
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We carried out a comparative study in 78 post-menopausal women with rheumatoid arthritis (RA). Forty-four women with a mean disease duration of 17.5 years had been treated with low-dose glucocorticoid (prednisone at 〈 5 mg/day) for at least 12 months. They were studied for an average period of 3 years and 8 months. The remaining 34 women had been treated only with non-steroidal anti-rheumatic drugs (NSAIDs) and served as the control group. Bone mineral density (BMD) in the lumbar spine (L2–4) and femoral neck was measured by dual-energy X-ray absorptiometry (DXA). Reduction of BMD in the lumbar spine was significant in both groups (P 〈 0.05 ∼ 0.01), but there was no statistically significant difference between the two groups. BMD of the femoral neck decreased significantly (P 〈 0.05) in the prednisone group, but again the difference was not significant between the two groups. Our data suggest that low-dose prednisone administration probably does not induce significant axial bone loss in female RA patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004020050348
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