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  • 1
    Electronic Resource
    Electronic Resource
    Microphotoluminescence and Raman scattering study of defect formation in diamond films (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3951-3957 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence and Raman spectroscopy are employed to explore the time evolution of defect formation in chemical vapor deposition diamond films for stages of growth spanning nucleation to continuous film formation. Our research is concentrated on three types of defects which give rise to the 1.68 eV optical band, the sp2 phase which centers at 1500 cm−1, and the broadband luminescence at 565–800 nm. The investigation of these types of defects suggests the following conclusions. Si atoms are most likely responsible for the creation of the 1.68 eV optical centers which takes place at the initial stages of growth. Plasma interactions with the Si substrate contribute to the 1.68 eV defect formation. The broad luminescence and sp2 bonding defects were not present in the isolated nuclei but were significantly present when a continuous film was formed. Two rates of diamond growth were obtained and the changes of the rates were attributed to the lowering degree of freedom available for the growth of the nuclei as well as to the formation of the sp2 phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352858
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  • 2
    Electronic Resource
    Electronic Resource
    Observation of surface modification and nucleation during deposition of diamond on silicon by scanning tunneling microscopy (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 6400-6405 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The surface topography of silicon substrates after the initial stages of diamond growth, by microwave plasma enhanced chemical vapor deposition, has been observed by scanning tunneling microscopy. The initial surfaces were polished with diamond paste before deposition to enhance nucleation, and the scratches were examined. After one half hour growth, the surface showed additional topography over all regions, and widely spaced faceted structures were detected which were attributed to diamond nuclei. The surface between nuclei showed increased roughness with increased deposition time. The faceted nuclei were found along the scratches. The nuclei showed facets which were smooth to within 5 A(ring). Fingerlike ridge structures were found extending from and in-between some of the nuclei. These structures indicate a mechanism of the lateral diamond growth. The electronic properties of the surface were probed by local I-V measurements, and characteristics attributable to SiC were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348843
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  • 3
    Electronic Resource
    Electronic Resource
    Femtosecond optical absorption measurements of electron-phonon scattering in GaAs quantum wells (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3188-3190 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a combined experimental and theoretical investigation of intra- and intersubband carrier relaxation in GaAs/AlAs quantum wells following femtosecond laser excitation at low density. Time-resolved optical absorption has been measured using 125 fs pulses from a tunable Ti:sapphire laser which allows carriers to be excited preferentially into different subbands. The experiments have been analyzed using a multi-subband Monte Carlo simulation which contains all the important scattering mechanisms. Electron-phonon scattering rates obtained from dielectric continuum theory have been used, and we find excellent agreement with the experiment. The dominance of interface phonons in intrasubband relaxation is confirmed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113718
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  • 4
    Electronic Resource
    Electronic Resource
    Electronic states in GaAs v-groove quantum wire structures with superlattice barriers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2851-2853 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a joint theoretical and experimental investigation of GaAs v-groove quantum wires confined in GaAs/AlAs superlattice barriers. We have computed the electronic states for both the quantum wire and the barriers. The intrinsic bending of the superlattice layers, together with systematic spatial variations of their thickness, create localized states in the barriers that are separated from the wire. This effect has a strong impact on the overall luminescence efficiency of the wires. The results are in excellent agreement with photoluminescence and photoluminescence excitation spectra. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114806
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  • 5
    Electronic Resource
    Electronic Resource
    The isolation of an allergen from extracts of Dermatophagoides pteronyssinus using a murine IgA myeloma with a specificity for phosphorylcholine (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 10 (1980), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The presence of a high molecular weight glycoprotein component bearing the hapten phosphorylcholine (Pc) has been demonstrated in some but not all extracts of house dust mite using a phosphorylcholine specific IgA myeloma protein (S107). The Pc bearing component was isolated from house dust mite extracts by precipitation at equivalence using whole myeloma serum and the isolated fraction was found to be allergenic as judged by a direct RAST assay using a highly house dust mite allergic human serum pool. RAST inhibition studies using free hapten and direct RAST studies using pneumococcal polysaccharide C-substance indicated that the Pe moiety did not contribute significantly to the immunodominant portion of the isolated allergen. Further studies indicated that the S107 isolated material was immunochemically different from the tridacnin reactive material and the con A reactive material previously isolated from extracts of house dust mite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1980.tb02144.x
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  • 6
    Electronic Resource
    Electronic Resource
    Prevalence and features of asthma in a sample survey of urban Goroka, Papua New Guinea (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 15 (1985), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study found a prevalence of asthma of 2.5% in adults and 0.2% in children in Goroka, the major town and administrative centre of the Eastern Highlands Province of Papua New Guinea. The disease features are similar to those found in previous studies in Papua New Guinea: late age of onset and virtual absence of childhood cases; strong association with allergy to house dust mite and high mite-specific IgE levels; and considerable impairment of resting lung function. However, the prevalence is much lower than that recently found in the nearby rural South Fore linguistic group of the Okapa District. Moreover, it was noted that a preponderance of the urban cases in the present study were originally from Okapa. The implication is that particular local tetiological factors may be responsible for the documented rise in prevalence in the South Fore (Okapa) people, rather than the process of ‘Westernization’per se. This creates a valuable opportunity to learn more about the pathogenesis of asthma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1985.tb02292.x
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  • 7
    Electronic Resource
    Electronic Resource
    Relationship between mite densities and the prevalence of asthma: comparative studies in two populations in the Eastern Highlands of Papua New Guinea (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 18 (1988), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The recent dramatic rise from 0.1 to 7.3% in the prevalence of adult asthma in the South Fore area of the Eastern Highlands of Papua New Guinea (PNG) has not been matched by a similar increase in asthma in the adjacent Asaro valley, where the prevalence remains extremely low at 0.3%. While the living conditions of these two populations appear comparable, the mean density of house dust mite (principally Dermatophagoides pteronyssinus) in blankets of residents in the Asaro valley was found to be significantly lower (283/g dust) than that of a corresponding random selection in the South Fore (1371/g dust). Since from 200 to 600 mites per g dust have been reported to constitute a risk factor for asthma, the data suggest that the relative risk for asthma in the Asaro valley population is low compared with that in the South Fore. In randomly selected sera, both IgE and IgG antibodies to D. pteronyssinus from the Asaro valley were comparable with those of a group of non-asthmatics from the South Fore (mean 4.39 vs 3.43 U/ml for IgE antibodies and 1832 vs 1815 U/ml for IgG antibodies for Asaro valley vs South Fore, respectively) but significantly lower (P 〈 0.001) than corresponding data for subjects in the South Fore with asthma (108.6 U/ml and 3365 U/ml, respectively). This study emphasizes the interplay between genetic and environmental factors in determining the development of asthma, and highlights the importance of house dust mites in the pathogenesis of asthma in the Eastern Highlands of Papua New Guinea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1988.tb02880.x
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  • 8
    Electronic Resource
    Electronic Resource
    Isotype specific immunoglobulin responses to the house dust mite Dermatophagoides pteronyssinus and the purified allergen Der p 1 in asthmatic and control subjects from the Eastern Highlands of Papua New Guinea (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 18 (1988), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The IgG, IgE and IgA antibody responses to the whole mite extract and a purified major mite allergen Der p 1, in sera from asthmatic and age- and sex-matched control subjects from the South Fore region of the Eastern Highlands of Papua New Guinea, have been studied. Radio-allergosorbent studies showed that the majority of the asthmatics, in contrast to control subjects, produced IgE to whole mite extract, and that Der p 1 was a major allergen in this population with 88% of mite allergic asthmatics responding. Enzyme-linked immunosorbent assay studies on these sera showed that the geometric mean levels of whole mite, but not Der p 1, specific IgG and IgA were significantly higher in the asthmatic group than in the control group. Significant correlations between whole mite specific IgG, IgE and IgA responses were obtained. These data indicate that Papua New Guinean asthmatics are similar to Caucasian asthmatic population with regard to serological responses to mite allergens, despite differences in disease presentation, particularly the late age of onset and severity of symptoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1988.tb02865.x
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  • 9
    Electronic Resource
    Electronic Resource
    Precipitating factors in respiratory allergic disease in Indonesian children (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 8 (1978), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Skin test results and IgE antibody levels measured by RAST indicate that hyper-sensitivity to house dust mite (D. pteronyssinus) is a major feature of asthma and allergic rhinitis in Indonesian children. Total serum IgE levels were higher in the allergic than in control children. 60% (twenty-one out of thirty-five) of the asthmatic children and 56% (five out of nine) of the children with allergic rhinitis had IgE antibodies to the helminth Ascaris lumbricoides compared with none out of four control children. A tendency was found for high IgE antibody levels to D. pteronyssinus to occur in association with low IgE antibody levels to A. lumbricoides and vice versa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1978.tb00459.x
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  • 10
    Electronic Resource
    Electronic Resource
    The effect of disodium cromoglycate (DSCG) on the levels of albumin and the immunoglobulins IgA, IgG, IgM and IgE in sputum (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 5 (1975), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Sputum samples from control subjects with cardiac disease and from patients with asthma were assayed for albumin content and immunoglobulins IgA, IgG, IgM and IgE. The asthmatics were divided into three groups: one group had received disodium cromoglycate (DSCG) for at least 48 hr prior to sampling, another group was sampled daily after commencing DSCG therapy and the third group were not taking DSCG. Albumin and immunoglobulins accounted for approximately 8% of the total sputum proteins in each of the four groups of subjects. There was no significant difference in the mean sputum levels of albumin or the immunoglobulins, when expressed as a percentage of total sputum proteins, between the subjects in each group. However, the ratios of IgA/albumin and IgA/IgG in the asthmatic group receiving DSCG were significantly lower than the corresponding ratios in sputa from both asthmatics and control subjects with cardiac disease. The sputum IgE levels tended to be higher in the asthmatics than in the control group, but DSCG therapy had little effect upon sputum IgE levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2222.1975.tb01836.x
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