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  • 1
    Electronic Resource
    Electronic Resource
    Properties of the second-order nonlinear optical susceptibility χ(2) in asymmetric undoped AlGaAs/InGaAs double quantum wells (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 1467-1471 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The second-order nonlinear optical susceptibility χ(2) for second-harmonic generation is calculated for the 11H transition of a graded double quantum well (DQW) structure of undoped GaAs/AlxGa1−xAs. These results are compared with the single quantum well (QW). Our results show that the values of χ(2) have optimal magnitudes dependent on the width, depth and separation between the QWs in a DQW structure. When the electric field increases, the dipole moment increases due to the increasing separation between the electron and hole wave functions. On the other hand, the oscillator strength of the 11H transition is reduced as a result of the decrease in the overlap of the electron and hole envelope functions. These two competing factors give rise to optimal conditions for the enhancement of the second-order nonlinear susceptibility χ(2). It is demonstrated that χ(2) for the DQW structure is more enhanced than for the biased single QW. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.370914
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  • 2
    Electronic Resource
    Electronic Resource
    Surface morphology effect on the photoresponse of high temperature superconducting microbridges (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 1306-1308 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Three Y1Ba2Cu3O7−δ superconducting thin films with 20%, 60%, and 100% coverage of precipitates were fabricated into microbridges of 25×650 μm2 by a conventional photolithography method. These microbridges exhibit a Tco(R=0) from 83.6 to 87.2 K and a transition width of about 1.8 K. These also have (dR/dt)max values of about 71–78 Ω/K. We find that the fewer the precipitates on the film, the better the thermal conduction, and a larger responsivity (S) can be achieved. The best responsivity of 783 V/W measured at Ib=8 mA, Top=86.8 K, and f=2 Hz for various wavelengths of light sources is obtained from the film with 20% precipitation. The photoresponse signals decay exponentially with the precipitation coverages, which indicates that these precipitates behave as thermal resistance layers that smooth out the ac incident signal, suppress the rise in microbridge temperature, and result in a smaller photoresponse signal for the bolometer. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117400
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  • 3
    Electronic Resource
    Electronic Resource
    Photo-pumped ZnCdSe/ZnCdMgSe blue-green quantum well lasers grown on InP substrates (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1351-1353 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the operation of new photo-pumped blue-green ZnCdSe/ZnCdMgSe graded-index separate confinement heterostructure single quantum well lasers grown lattice matched on InP substrates. Laser emission at 512 nm was observed. The T0 value is 150 K at room temperature. These materials are proposed as alternative materials for the fabrication of visible semiconductor lasers. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118576
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  • 4
    Electronic Resource
    Electronic Resource
    Bolometric detection in a precipitation free Y1Ba2Cu3O7−δ film at 77 K (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2741-2743 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A photodetector with high responsivity has been fabricated with a high quality Y1Ba2Cu3O7−δ film on a regular SrTiO3 (100) substrate that has no thinning or etching. The film exhibits a precipitation-free morphology and has an extremely smooth surface having a rms roughness smaller than 5 nm. The film was patterned into a 25×650 μm2 long microbridge by a conventional photolithography technique. The Tco of the microbridge can be tuned by applying different bias currents, which results in a tunable operation temperature of the photodetector at 77.35±1 K. This makes it operationally more practical and economical. The noise voltage at 10 mA bias current is less than the resolution of our setup, 15 nV Hz−0.5. A high responsivity of 2.3×103 V/W was obtained when a bias current of 8 mA and a low power density He–Ne laser of 0.08 J/cm2 s chopped at 2 Hz were applied on the microbridge at 77.35 K. Under the same condition, the noise equivalent power (NEP) and detectivity (D*) have been measured to be 4.34×10−12 W Hz−0.5 and 3×109 cm Hz0.5 W−1, respectively. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115583
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  • 5
    Electronic Resource
    Electronic Resource
    Detection of dural involvement by magnetic resonance imaging in adult patients with acute leukemias — preliminary experience (1995)
    Springer
    Annals of hematology 70 (1995), S. 243-249 
    Details
    ISSN: 1432-0584
    Keywords: Acute leukemia ; Dura ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Retrospectively, the dura in 18 adult patients with acute leukemia were evaluated by gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). Abnormal dural enhancements were detected in three of four patients with positive cerebrospinal fluid (CSF) cytology, in one of five with suspicious central nervous system (CNS) disease, and in two of nine asymptomatic patients. Computed tomography failed to demonstrate any dural abnormality in these six patients. The abnormal dural enhancement was found in either (a) the brain and the spine, (b) the thoracolumbar spine, or (c) the area adjacent to the parenchymal lesions. Three of the patients were in hematological remission stage; disappearance of the abnormal dural enhancement was observed 1–2 months after radiotherapy and high-dose systemic chemotherapy. The results suggest that MRI is a sensitive and noninvasive imaging modality and superior to CT in detecting dural disease in leukemic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784043
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  • 6
    Electronic Resource
    Electronic Resource
    Detection of dural involvement by magnetic resonance imaging in adult patients with acute leukemias – preliminary experience (1995)
    Springer
    Annals of hematology 70 (1995), S. 243-249 
    Details
    ISSN: 1432-0584
    Keywords: Key words Acute leukemia ; Dura ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Retrospectively, the dura in 18 adult patients with acute leukemia were evaluated by gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). Abnormal dural enhancements were detected in three of four patients with positive cerebrospinal fluid (CSF) cytology, in one of five with suspicious central nervous system (CNS) disease, and in two of nine asymptomatic patients. Computed tomography failed to demonstrate any dural abnormality in these six patients. The abnormal dural enhancement was found in either (a) the brain and the spine, (b) the thoracolumbar spine, or (c) the area adjacent to the parenchymal lesions. Three of the patients were in hematological remission stage; disappearance of the abnormal dural enhancement was observed 1–2 months after radiotherapy and high-dose systemic chemotherapy. The results suggest that MRI is a sensitive and noninvasive imaging modality and superior to CT in detecting dural disease in leukemic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784043
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  • 7
    Electronic Resource
    Electronic Resource
    Flavonoids as inducers of extracellular proteins and exopolysaccharides of Sinorhizobium fredii (1999)
    Springer
    Biology and fertility of soils 30 (1999), S. 83-89 
    Details
    ISSN: 1432-0789
    Keywords: Key words Sinorhizobium fredii ; Flavonoids ; Extracellular proteins ; Exopolysaccharides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Some flavonoids present in root exudates are inducers of nod genes in rhizobia-legume symbioses. They also induce changes in the molecular weight, structure, and level of secretion of some extracellular proteins, exopolysaccharides (EPS) and lipopolysaccharides. We showed that incubation of Sinorhizobium fredii USDA 257 with four flavonoids (genistein, naringenin, chrysin, and apigenin) promoted its growth in the late log phase. By contrast, only genistein accelerated the growth of S. fredii TU 6 under the same conditions. When both strains were incubated with naringenin the synthesis of EPS decreased. However, this compound increased the secretion of extracellular proteins in the early log phase. The specific mode of action of naringenin is still not clear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050591
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  • 8
    Electronic Resource
    Electronic Resource
    Comparative Evaluation on the Biological Monitoring of Exposure to Parathion and Its Methyl Analog (1997)
    Springer
    Archives of environmental contamination and toxicology 32 (1997), S. 422-425 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. The effects of both parathion and methyl parathion on the inhibition of plasma cholinesterase were elaborated in a rat model employing a modified isocratic reverse-phase HPLC method coupled with UV detection for the determination of the urinary metabolite p-nitrophenol (U-4NP). A linearity of r2 〉 0.995 was found for a standard curve ranging from 0.06 to 0.96 μg/mL with a % relative error of ≤±10% and a recovery of 89 ± 2%. The % CV at all levels was ≤11%. A linear correlation was observed between the oral administration of parathion and methyl parathion for both the percent inhibiton of cholinesterase as well as the urinary elimination of 4NP. It is tentatively recommended that an U-4NP of 2.0 mg/g creatinine be established as a biological exposure index (BEI) for methyl parathion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900207
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  • 9
    Electronic Resource
    Electronic Resource
    Subtyping of human T-lymphotropic virus type I by amplification of long terminal repeat sequences and restriction fragment length polymorphism analysis in carriers with multiple transfusions (1996)
    Springer
    Annals of hematology 73 (1996), S. 127-134 
    Details
    ISSN: 1432-0584
    Keywords: Key words Human T-lymphotropic virus type I ; Long terminal repeat ; Restriction fragment length polymorphism ; Polymerase chain reaction ; Transfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Five major subtypes of human T-lymphotropic virus type I (HTLV-I) have been proposed: cosmopolitan, Japanese, West African, Central African, and Melanesian. Based on nucleotide variations specific to particular subtypes, it was possible to genotype HTLV-I rapidly by restriction fragment length polymorphism (RFLP) studies following polymerase chain reaction (PCR) . In this study, the restriction patterns of two LTR fragments were analyzed using eight restriction endonucleases (AvaI, Eco57I, BsoFI, NdeI, SacI, DraI, MaeII, and MaeIII). Genotyping of HTLV-I was done in nine patients with adult T-cell leukemia or HTLV-I-associated myelopathy/tropical spastic paraparesis, in three prostitutes, and in 19 carriers with multiple transfusion in Taiwan. The subtyping results of RFLP studies using these eight restriction endonucleases were in accordance with those of phylogenetic analysis. A substitution of G by A at nucleotide position 503, which creates the DraI site but suppresses the SacI site, was found not only in the Japanese subtype but also in a minority of the cosmopolitan subtype. A mutation near the position of subtype-specific nucleotide variations might suppress the restriction site and lead to unexpected restriction patterns. Amplification of more than one proviral fragment and RFLP studies with a group of appropriate restriction endonucleases may provide rapid and accurate genotyping of HTLV-I. More carriers are required to evaluate the possibility of mixed infection with different HTLV-I subtypes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002770050213
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  • 10
    Electronic Resource
    Electronic Resource
    Mandibular mass as the presenting manifestation of IgM myeloma in a 22-year-old man (1999)
    Springer
    Annals of hematology 78 (1999), S. 93-95 
    Details
    ISSN: 1432-0584
    Keywords: Key words IgM myeloma ; Mandibular mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report here the youngest known IgM myeloma patient to have presented with a mandibular mass. A 22-year-old Chinese man sought medical attention due to a mass over his right mandible that had been growing progressively for 6 months. A solitary osteolytic lesion in the right mandible was identified radiologically. Incisional biopsy revealed the presence of plasma cells of monoclonal origin, as evidenced by the exclusively positive staining of the kappa light chain. The diagnosis of multiple myeloma with mandibular involvement was confirmed by bone marrow examination. Further tests, including immunoglobulin electrophoresis and assay of the serum levels of kappa and lambda light chains, demonstrated that his myeloma was of the IgM, kappa subtype. The patient achieved a nonsustained partial response to six courses of melphalan and prednisolone therapy and palliative radiotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002770050481
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