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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2494-2496 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the propagation of quasiparticles in a superconducting film which is penetrated by a magnetic field. We inject quasiparticles into an Al film at 75 mK using a normal–insulator–superconductor tunnel junction and measure the flux of quasiparticles which diffuse into an adjoining thermal detector. A magnetic field applied perpendicular to the plane of the film produces regions of reduced energy gap which trap quasiparticles. We find a significant reduction in the quasiparticle flux for fields as small as 2 G and explain our measurements with a model that incorporates inelastic scattering rates in Al and the characteristics of field penetration. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2705-2707 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present measurements and theoretical modeling of two normal/insulator/superconductor tunnel junction microrefrigerators. The first device, fabricated on a thick silicon substrate, had a cooling power of 36 pW, an active volume of 350 μm3, and a temperature drop for electrons of 2 mK from a 300 mK bath. The second device, fabricated on a thin silicon nitride membrane, had a cooling power of 4 pW and cooled both electrons and phonons in a similar volume by almost 2 mK from a bath of 300 mK. These are the largest cooling powers and active volumes for electron and phonon refrigeration reported to date. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1062-1064 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The incorporation of hydrogen in ZnSe:N and ZnSe:Cl films grown by gas source molecular beam epitaxy (GSMBE) using elemental Zn and H2Se as source material has been investigated. The hydrogenation behavior was found to be significantly enhanced when nitrogen was used as a dopant, and typically resulted in highly resistive films. On the other hand, Cl-doped ZnSe films showed a hydrogen concentration at or near the background levels independent of the Cl concentration. ZnSe was also grown by conventional molecular beam epitaxy with intentionally introduced H2 in order to clarify the source of the hydrogen. Significant hydrogen incorporation was observed in the MBE-grown ZnSe:N layers only when hydrogen gas was introduced. Injection of hydrogen in excess of the amount generated during typical GSMBE experiments was found to give rise to an unambiguous increase in the hydrogen concentration, but with a hydrogen:nitrogen ratio less than that measured in GSMBE films. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The pathogenesis of nasal polyp disease is poorly understood. Recent evidence has suggested that nitric oxide (NO), an endogenous soluble gas vasodilator and inflammatory mediator, may be synthesised within the nasal cavity. Three nitric oxide synthase isoforms have been identified in humans, with the inducible isoform (iNOS) generally expressed in the setting of inflammation.〈section xml:id="abs1-2"〉〈title type="main"〉ObjectiveThe aim of this study was to detect and localize iNOS expression in nasal polyp tissue, and compare these findings with normal nasal turbinate tissue.〈section xml:id="abs1-3"〉〈title type="main"〉MethodsWe examined the expression and localisation of inducible nitric oxide synthase (iNOS) in human nasal airway specimens from patients undergoing elective nasal turbinectomy (n = 5) or nasal polypectomy (n = 5). iNOS mRNA expression was determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern blot analysis and localised by in situ hybridization. Densitometric data were analysed using Student's unpaired t-test. Adjacent sections were also examined for iNOS protein expression by immunohistochemistry.〈section xml:id="abs1-4"〉〈title type="main"〉ResultsSemi-quantitative RT-PCR/Southern analysis of RNA obtained from the 10 surgical specimens demonstrated that iNOS mRNA expression was significantly increased in the five nasal polyps (P 〈 0.05). In situ hybridization studies revealed strong iNOS mRNA signal localized to the respiratory epithelium of nasal polyps, but not nasal turbinates. This pattern was confirmed by immunohistochemistry. Localization to inflammatory cells or other subepithelial structures was not seen.〈section xml:id="abs1-5"〉〈title type="main"〉ConclusionsWe conclude that iNOS expression is upregulated in nasal polyp disease, and is localized to the polyp epithelial layer. These data reinforce the concept that the epithelial layer may be important in the pathogenesis of nasal disease, and suggest a potential role for NO in the formation of nasal polyps.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 96 (1998), S. 969-979 
    ISSN: 1432-2242
    Keywords: Key words Molecular markers ; Pinus radiata ; Microsatellites ; Multi-copy ; Null alleles ; Mutation rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Dinucleotide microsatellites were isolated from Pinus radiata using both a standard genomic library and libraries enriched for microsatellites. Locus-specific primers were designed to amplify 43 unique microsatellites. Thirty two of these loci had interpretable PCR patterns, 11 of which were polymorphic in a screen of 19 P. radiata individuals; all 11 polymorphic loci contained at least 17 repeats in the sequenced plasmid. Six of the eleven primer pairs amplified multiple fragments per individual (3–8), suggesting that these loci were present in multiple copies in the genome. Genotyping a 48-tree P. radiata production population with seven of the most polymorphic microsatellites revealed an average of 17 bands per locus (the multi-copy microsatellites were treated as one locus). When tested on known pedigrees, both single and multi-copy microsatellites exhibited co-dominant inheritance and Mendelian segregation. Two loci had null alleles and one locus had a high frequency of non-parental alleles, suggesting a high mutation rate. Eight of these microsatellites, including five multi-copy loci, were placed on a partially constructed P. radiata genetic map. Four of the five multi-copy microsatellites had two or more sets of alleles that mapped to the same locus, and the fifth mapped to two unlinked loci. All seven tested primer pairs amplified PCR products from other species of hard pine, three amplified products from soft-pine species, and one amplified bands in other conifers.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 217-222 (May 1996), p. 159-164 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bradford, West Yorkshire [u.a.] : Emerald
    Journal of property valuation & investment 16 (1998), S. 99-108 
    ISSN: 0960-2712
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Economics
    Notes: This article discusses the future of property valuation data provision by examining a new data initiative designed to increase valuation data availability known as a National Valuation Evidence Database (NVED). This NVED will be an on-line source of comparable evidence which, when combined with the National Land Information System, will provide valuers with a single source of on-line valuation evidence. It is argued that the future of valuation data provision will revolve around these two initiatives and that it is up to property professionals to take the lead in encouraging these initiatives, to indicate to their clients a progressive attitude towards property service provision.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0983
    Keywords: Key words Mitochondria ; Ribosomal RNA ; RNA editing ; Polycistronic transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Northern analyses and reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed on total RNA of Dictyostelium discoideum. The mitochondrial genes encoding the small subunit ribosomal RNA (SSU), cytochrome b (CYTB) and subunit 3 of the NADH dehydrogenase (ND3) were found to be co-transcribed. Further post-transcriptional processing resulted in a dicistronic transcript for CYTB and ND3, and a monocistronic SSU transcript. Markedly higher steady state transcript levels were detected for the mature SSU ribosomal RNA. A comparison of the SSU cDNA sequence with the mitochondrial DNA sequence of the SSU gene revealed C-to-U substitutional editing of the SSU ribosomal RNA at a single site, as a consequence of which the cDNA contained a PvuII site not present in the genomic DNA. The editing was shown to be highly efficient and to occur in the primary transcript before the release of the mature mRNA, rRNA and tRNAs. It is suggested that the editing may be required for normal pseudoknot formation in the 530 loop of the RNA and thus is important for efficient, accurate translation in the mitochondria.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 101 (1995), S. 561-566 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a design for a novel electronic refrigerator having a base temperature of about 18 mK when operating from a bath temperature as high as 1.5 K. This all-electronic refrigerator is a factor of 104 smaller and lighter than dilution and adiabatic demagnetization refrigerators, and is compatible with conventional photolithographic fabrication. The refrigerator, based on the unique thermal transport properties of a normal-insulator-superconductor (NIS) tunnel junction, preferentially removes electrons whose energy is higher than the Fermi energy from a normal metal. Electrons with an average energy equal to the Fermi energy are returned to the metal by a superconductor contact. Consequently, high energy thermal excitations are removed from the normal metal, thus cooling the electrons. In our configuration, the junction is deposited on a Si3N4 membrane of submicron thickness that thermally isolates the normal electrode from the bath. As a result, both electrons and phonons in the metal are cooled below the bath temperature. We calculate a cooling power of 2 nW at 100 mK, and a base temperature of 18 mK for a refrigerator area of about 100X100 μm2. Using 105 such refrigerator circuits, the cooling power can be increased to 200 μW.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1433-0350
    Keywords: Key words Craniopharyngioma ; Brain neoplasms ; Children ; Surgery ; Radiotherapy ; Relapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Past studies of craniopharyngiomas in children have shown overall survival (OS) up to 95% at 5 years and 80% progression-free survival (PFS) at 5 years, although many of these series predate modern neuroimaging and current therapeutic management. Moreover, little mention has been made of failure patterns for craniopharyngioma in children. To obtain a contemporary assessment of outcome among pediatric craniopharyngioma patients, and also to determine the failure patterns for this tumor, we completed a retrospective study of a consecutive cohort of all children with craniopharyngioma diagnosed at the Johns Hopkins Hospital from 1980 to 1996. Resection was performed in 30 children, in 8 of whom gross total resection (GTR) was achieved. Initial treatment took the form of GTR followed by observation for 8, subtotal resection (STR) plus observation in 11, and STR followed immediately by radiotherapy in 8. The timing of radiotherapy following STR was unclear for 3. OS was 95.2% (SE= 4.7%) at 5 years, with only 2 children dying after 4 years from diagnosis. Five-year PFS was 59.4% (SE=10.2%). Before surgery, 19 children had visual loss and 15, endocrine deficits; after surgery, 21 children had visual loss and 29, endocrine deficits. Median time to relapse was 0.98 years (SD=2.5 years). Radiographic (n=4) and clinical (n=7) relapses did not differ in time to progression (P=0.32), but radiographic relapses were significantly associated with age at diagnosis less than 5 years (P=0.02). Degree of resection was not significantly associated with PFS (P=0.32) or with postoperative visual or endocrine deficits. Absence of calcification on diagnostic neuroimaging (n=8) was significantly associated with improved PFS [5-year PFS 100% vs. 42.9% (SE=14.7%), P=0.02], even when adjusted for extent of resection (P=0.03). Preoperative visual loss was predictive of postoperative visual loss (P=0.03). Survival for children diagnosed with craniopharyngioma in the current era is outstanding, even with relapse, although postoperative visual and endocrinological morbidities are high. Failures occurred both radiographically and clinically, typically in the first 3–4 years after surgery, suggesting a need for close surveillance initially with neuroimaging, particularly in younger children, and also clinical examination. The short times to relapse observed here may stem from a tendency to delay radiotherapy until recurrence. Lack of calcification at diagnosis is associated with a tendency to remain free of relapse.
    Type of Medium: Electronic Resource
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