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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 2701-2703 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Si/Si0.85Ge0.15/Si p-type modulation-doped double heterostructures have been grown by the ultrahigh vacuum/chemical vapor deposition technique, and mobility enhancement has been observed at low temperatures. For heterostructures with Si layers doped with boron to ∼1×1019 cm−3, hole mobilities of ∼900 cm2/V s at 14 K have been obtained. No carrier freeze-out behavior has been observed at low temperatures. The existence of two-dimensional hole gas was determined by the tilted-field Shubnikov–de Haas measurement. Both Si/SiGe and SiGe/Si heterointerfaces were found to be equivalent and of excellent interfacial quality. The valence-band maximum of Si0.85Ge0.15 alloy has been estimated to be (approximately-equal-to)0.95 meV higher than that of Si. A hole effective mass of 0.44±0.03m0, which is consistent with the interpolation of the bulk band structures for the Si0.85Ge0.15 alloy, has been obtained for the heterostructure.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2333-2335 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High quality Si/Si1−xGex/Si p-type modulation-doped double heterostructures with x=0.12 and 0.15 have been grown by the ultrahigh vacuum/chemical vapor deposition technique. Hole mobilities as high as ∼3700 cm2/V s at 14 K have been obtained for heterostructures with x=0.12, at a sheet carrier concentration of ∼8×1011 cm−2. This is the highest hole mobility ever reported for p-type Si material at these carrier concentrations. The electrical properties of these heterostructures at low temperatures are those expected of a two-dimensional hole gas at Si/SiGe and SiGe/Si heterointerfaces. The high hole mobility is indicative of excellent interfacial properties. Peak mobilities were observed to depend on the level and proximity of remote B dopant species, as well as the Ge content of the alloyed layers.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric radiology 17 (1987), S. 80-81 
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of pyelocalyceal diverticula in a patient with the Beckwith-Wiedemann syndrome is presented. The abnormalities were first identified on screening ultrasound and confirmed at excretory urography. The diverticula in this syndrome are likely secondary to hereditary embryopathy of the kidneys.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric radiology 18 (1988), S. 169-171 
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Juvenile xanthogranuloma is a benign histiocytosis of infancy and childhood characteristically involving the skin, the eye, and, rarely, the lungs, liver and mesothelial structures. This report documents the first known case of renal involvement which is demonstrated by ultrasound and computed tomography.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric radiology 19 (1989), S. 479-480 
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lesch-Nyhan syndrome is a rare X-linked recessive disorder of purine metabolism associated with a virtually complete deficiency of the enzyme hypoxanthine-guanine phosphoribosyl-transferase (HPRT). The disease is characterized by hyperuricemia, self-multilation, choreoathetosis, spasticity, and mental retardation. The abnormalities of purine metabolism are present at birth and may lead to uric acid crystalluria and stone formation early in life [1]. Radiographic findings described in Lesch-Nyhan syndrome include faintly radio-opaque stones on abdominal radiographs or, if renal disease is present, small kidneys with poor function on intravenous urogram. Radiolucent stones are usually composed of uric acid; however, several cases of xanthine and hypoxanthine-containing calculi in Lesch-Nyhan patients receiving allopurinl therapy have also been described [2, 3]. Oxypurine is the collective name for the compounds hypoxanthine, xanthine, and uric acid, and all may be radiolucent. We report a case of Lesch-Nyhan syndrome with presumed renal parenchymal oxypurine deposition demonstrated readily by ultrasonography but not detected on standard radiographs or intravenous urograms.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2242
    Keywords: Gametoclonal variation ; Barley doubled haploids ; Wheat doubled haploids ; Hordeum bulbosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To investigate whether the Hordeum bulbosum system of doubled haploid production generates gametoclonal variation, populations of second generation doubled haploid lines were developed from first generation doubled haploid lines of two barley varieties and three wheat genotypes. In barley, no variation between doubled haploids from doubled haploids was detected for a range of quantitative characters, suggesting the absence of any gametoclonal effects. However, the original selfed-seed stocks were shown to contain cryptic allelic variation for some of the characters investigated. In wheat, gametoclonal variation was detected for ear emergence time, plant height and yield, and its components for two out of the three genotypes investigated. The type and range of variation was similar to that reported from studies of somaclonal variation from immature embryos and gametoclonal variation from anther culture. Generally, the effects appeared to reduce the yield performance of individual lines. The difference in response between the two species and the consequences for the use of the doubled haploid system in breeding programmes are discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 71 (1985), S. 518-526 
    ISSN: 1432-2242
    Keywords: Wheat ; Vernalisation genes ; Agronomic characters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chromosome 5A of bread wheat, Triticum aestivum carries the major gene, Vrnl, which is one of the main determinants of the winter/spring growth habit polymorphism in this species. Genetical analysis of this chromosome has been carried out using single-chromosome recombinant lines to establish the pleiotropic effects of this locus and two other major genes, q determining ear morphology and bl determining the presence of awns, on important agronomic characters. The three major genes were located on the long arm of chromosome 5A with a gene order of: centromere -bl-q-Vrnl. Analysis of quantitative characters from a winter sowing revealed pleiotropic effects of Vrnl or the effects of closely linked loci on the characters plant height, tiller number and spikelet number. However effects on ear emergence time were not associated with Vrnl but with q as were effects on spikelet number and ear length. In addition a locus determining yield/plant was located between Vrnl and q. Independant loci determining height and ear length were apparent on the short arm of chromosome 5A. From a spring sowing, however, there was a large pleiotropic effect of Vrnl on ear emergence time, as well as the effects previously detected. In addition, associated with q were effects on plant height and grain size which were not expressed from the winter sowing.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 24 (1989), S. 2177-2182 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The α-phase of the Al−Mn−Si ternary system has been precipitated from four liquid solutions (2.8 wt% Mn−3.7 wt% Si, 4.5 wt% Mn−7 wt% Si, 7.7 wt% Mn−10 wt% Si and 8.7 wt% Mn−12.6 wt% Si) and equilibrated slightly over the melting point of the (secondary) solid solution. Quenching into water enabled the precipitates to be separated from the solid solution and the co-nodal tie-lines for the α-phase and liquid to be determined. The silicon content varied from 9.8 to 11.8 wt%, while the manganese content, 29.6±0.6 wt%, did not vary significantly. The lattice parameter of the cubic unit cell decreased from 1.267 6(2) nm to 1.265 10(4) nm with increasing silicon. Neutron powder diffraction showed silicon to constitute approximately 50% of atoms on the icosahedral aluminium sublattices and 70% of a six-fold aluminium site in the interstices between the almost spherical, 54-atom clusters. This decrease in unit cell volume is interpreted as evidence for substitution of the silicon atoms on the six-fold sublattice.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1988), S. 88-90 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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