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  • 1
    Electronic Resource
    Electronic Resource
    Carrier relaxation dynamics in an ultrafast all-optical modulator using an intersubband transition (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 4509-4511 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An improvement of an all-optical modulation scheme that utilizes an intersubband transition is proposed and investigated in connection with intersubband carrier relaxation dynamics. N-doped GaAs/AlGaAs quantum wells are pumped by an ultrashort (∼120 fs) intersubband-resonant pulse and probed by an interband-resonant white-light continuum. Ultrafast modulation speed of ∼0.4 ps is demonstrated, which is faster than that of the previous scheme by as much as a factor of 10. It is found that a large part of the carriers, which are excited from the first conduction subband to the second conduction subband, transfer to unknown trapping states at a relaxation time that is comparable to that of the pump–pulse duration. The existence of the carrier relaxation path via L valley subbands is strongly suggested as the cause. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1427154
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  • 2
    Electronic Resource
    Electronic Resource
    Pump-probe measurement of ultrafast all-optical modulation based on intersubband transition in n-doped quantum wells (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 19-21 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Modulation of interband-resonant light (∼800 nm) by intersubband-resonant light (5–7 μm) was investigated in n-doped AlGaAs/GaAs multiple quantum wells by a two-color femtosecond pump-probe technique. Modulation with a recovery time of ∼1 ps is observed in a plainer-type modulation device at room temperature. The modulation of interband absorption coefficient is ∼1000 cm−1 when the energy density of the intersubband light pulse is ∼4 fJ/μm2. The modulation efficiency indicates that 99% modulation can be achieved with a control pulse energy of ∼1 pJ when a conventional waveguide-type device structure is utilized. The mechanism which determines the modulation speed is discussed in terms of carrier relaxation process. It is shown that the modulation speed is mainly determined by the inter- and intrasubband relaxation times, where the latter is influenced by hot phonon effects. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126863
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  • 3
    Electronic Resource
    Electronic Resource
    Anticentromere Antibody as a Risk Factor for Cancer in Patients with Systemic Sclerosis (2000)
    Springer
    Clinical rheumatology 19 (2000), S. 123-126 
    Details
    ISSN: 1434-9949
    Keywords: Key words:Anticentromere antibody – Cancer – Systemic sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: This study has estimated the cancer risk among patients with systemic sclerosis (SSc) using a population-based analysis. Using the inpatient and outpatient registries for patients at Kyushu University Hospital between 1982 and 1996, standardised incidence rates (SIRs) (ratio of observed-to-expected cancers) were calculated in 43 patients with SSc, 24 patients with polymyositis (PM) and 17 patients with dermatomyositis (DM). Risk factors predisposing to cancers were also investigated in the SSc patients. Compared with the Japanese general population, the SIR for developing cancer in SSc patients was 5.1 (95% confidence interval (CI), 1.7–10.8), while the SIRs for cancer in the PM and DM groups were 4.7 (95% CI, 1.5–10.3) and 61.2 (95% CI, 46.8–77.6), respectively. A statistically significant risk factor for cancers in the SSc patients was positivity for anticentromere antibody (ACA) (p〈0.05), while the erythrocyte sedimentation rate, serum lactate dehydrogenase concentration, serum γ-globulin concentration, titre of antinuclear antibody and positivity for antitopoisomerase I antibody were not associated with cancer in SSc. Our population-based study confirms the increased risk of cancer among patients with SSc in Japan and provides new evidence that positivity for ACA should be considered as a risk factor for cancer in future monitoring of patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100670050029
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  • 4
    Electronic Resource
    Electronic Resource
    Factors correlated with emotional instability in SLE outpatients (2000)
    Springer
    Modern rheumatology 10 (2000), S. 31-37 
    Details
    ISSN: 1439-7609
    Keywords: Key words Systemic lupus erythematosus ; Emotional instability ; Social factors ; Medical factors ; Physical factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Eighty-four female outpatients with systemic lupus erythematosus (SLE) who are able to live on their own were investigated. We statistically analyzed the relationship between emotional instability based on psychological tests (Cornell Medical Index), and physical, medical, and social factors based on both our clinical records and original questionnaires. The emotional instability was related to not "working," an older "age at the time of SLE diagnosis," being "anxious about the adverse effects of steroids," or not "understanding the details of the disease and treatment at the time SLE treatment was started." No relationship with previously experienced physical factors was observed. In addition, no relationship with disease activity was observed either. We identified the characteristic correlation between emotional instability and medical and social factors in this study. Paying close attention to these factors may thus be useful in both preventing the appearance of psychological problems and developing effective early treatment strategies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101650070036
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