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  • 2000-2004  (7)
  • 1975-1979
  • 2004  (1)
  • 2000  (6)
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  • 2000-2004  (7)
  • 1975-1979
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  • 1
    Electronic Resource
    Electronic Resource
    Isoelectronic As doping effects on the optical characteristics of GaN films grown by metalorganic chemical-vapor deposition (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 2819-2821 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the As doping effects on the optical characteristics of GaN films by time-integrated photoluminescence and time-resolved photoluminescence. When As is incorporated into the film, the localized defect levels and donor–acceptor pair transition become less resolved. The recombination lifetime of neutral-donor-bound exciton (I2) transition in undoped GaN increases with temperature as T1.5. However, the I2 recombination lifetime in As-doped GaN first decreases exponentially from 98 to 41 ps between 12 and 75 K, then increases gradually to 72 ps at 250 K. Such a difference is related to the isoelectronic As impurities in GaN, which generate nearby shallow levels that dominate the recombination process. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1316075
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  • 2
    Electronic Resource
    Electronic Resource
    Time-resolved photoluminescence study of isoelectronic In-doped GaN films grown by metalorganic vapor-phase epitaxy (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3224-3226 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Time-resolved photoluminescence spectra were used to characterize isoelectronically doped GaN:In films. Our results indicate that the recombination lifetime of the donor-bound-exciton transition of undoped GaN exhibits a strong dependence on temperature. When In is doped into the film, the recombination lifetime decreases sharply from 68 to 30 ps, regardless of the measured temperature and In source flow rate. These observations might be related to the isoelectronic In impurity itself in GaN, which creates shallow energy levels that predominate the recombination process. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126588
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  • 3
    Electronic Resource
    Electronic Resource
    Enhancement of p-type doping of ZnSe using a modified (N+Te)δ -doping technique (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 2205-2207 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Delta doping techniques have been investigated to enhance the p-type doping of ZnSe. Tellurium was used as a codopant for improving the nitrogen doping efficiency. The net acceptor concentration (NA−ND) increased to 1.5×1018 cm−3 using single δ doping of N and Te (N+Te), while it was limited to 8×1017 cm−3 by δ doping of N alone. A promising approach was developed in which three consecutive δ-doped layers of N+Te were deposited for each δ-doping cycle. An enhancement in the (NA−ND) level to 6×1018 cm−3 has been achieved in ZnSe using this technique. The resultant layer has an average ZnTe content of only about 3%. This doping method shows potential for obtaining highly p-type doped ohmic contact layers without introducing significant lattice mismatch to ZnSe. Low-temperature photoluminescence spectra reveal some Te-related emissions. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126297
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  • 4
    Electronic Resource
    Electronic Resource
    Identification of Neurones in the Female Rat Hypothalamus That Express Oestrogen Receptor-Alpha and Vesicular Glutamate Transporter-2 (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Oestrogen exerts its effects in the brain by binding to and activating two members of the nuclear receptor family, oestrogen receptor (ER)-α and ER-β. Evidence suggests that oestrogen-receptive neurones participate in the generation of reproductive behaviours and that they convey the oestrogen message to gonadotropin-releasing hormone (GnRH) neurones. The aim of the present study was to identify the neurochemical phenotype of a subset of oestrogen receptor-expressing neurones. To this aim, we focused on the glutamate neuronal system, which is one of the most important stimulators of GnRH synthesis and release. We used the presence of vesicular glutamate transporter-2 (VGLUT2) mRNA as a specific marker to identify glutamate neurones and employed dual in situ hybridization to localize ERα mRNA-(35S-labelling) and VGLUT2 mRNA-(digoxigenin-labelling) expressing neurones within the hypothalamus. The results show that the overall distribution of VGLUT2 mRNA and ERα mRNA are consistent with previous data in the literature. Dual-labelled neurones were localized in the ventrolateral part of the ventromedial nucleus where 81.3 ± 3.4% of the ERα mRNA containing neurones expressed VGLUT2 mRNA, in the anteroventral periventricular nucleus (30% colocalization) and in the medial preoptic nucleus (19% colocalization). Only 4.4% of the ERα expressing neurones in the arcuate nucleus contained VGLUT2 mRNA. These findings reveal that certain subpopulations of oestrogen-receptive neurones are glutamatergic in select hypothalamic areas that are known to regulate reproductive behaviour and GnRH neurones in the female rat. Thus, the oestrogen signal could be propagated through glutamate neurones to distant sites and influence the activity of the postsynaptic neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.2004.01109.x
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  • 5
    Electronic Resource
    Electronic Resource
    Production and characterization of monoclonal antibodies to serine proteinase allergens in Penicillium and Aspergillus species (2000)
    Oxford BSL : Blackwell Science Ltd
    Clinical & experimental allergy 30 (2000), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Alkaline and/or vacuolar serine proteinases are major allergens in prevalent airborne Penicillium and Aspergillus species.〈section xml:id="abs1-2"〉〈title type="main"〉ObjectiveThe object of this study is to generate and characterize monoclonal antibodies against these serine proteinase allergens.〈section xml:id="abs1-3"〉〈title type="main"〉MethodsBALB/c mice were immunized individually with the Penicillium citrinum culture medium or the crude extract and culture medium preparations of Aspergillus fumigatus. Hybridoma cells that secrete monoclonal antibodies against serine proteinase allergens were selected by immunoblotting. Antigens in three different Penicillium (P. citrinum, P. notatum and P. oxalicum) and two different Aspergillus species (A. fumigatus, and A. flavus) recognized by these monoclonal antibodies were analysed by sodium dodecyl sulphate and two-dimensional polyacrylamide gel electrophoresis immunoblotting and N-terminal amino acid sequence analysis.〈section xml:id="abs1-4"〉〈title type="main"〉ResultsFour (PCM8, PCM10, PCM16 and PCM39) and one (FUM20) monoclonal antibodies against serine proteinase allergens were generated after fusion of NS-1 cells with spleen cells obtained from BALB/c mice immunized with antigens from P. citrinum and A. fumigatus, respectively. Immunoblotting results showed that PCM8 reacted with an alkaline serine proteinase allergen in P. citrinum and P. notatum. PCM10 and PCM39 reacted with the alkaline serine proteinase in two Penicillium (P. citrinum, P. notatum) and two Aspergillus species (A. fumigatus, and A. flavus) tested. PCM16 reacted with the alkaline serine proteinase allergen in P. citrinum, A. fumigatus and A. flavus but not with that in P. notatum. MoAb FUM20 reacted with the alkaline serine proteinase allergen in two Aspergillus species (A. fumigatus and A. flavus) but not with that in two different Penicillium species (P. citrinum, P. notatum) tested. Among these five monoclonal antibodies generated, only PCM39 and FUM20 can react with the vacuolar serine proteinase allergen in P. notatum, P. oxalicum and in A. fumigatus. The 35 kDa P. citrinum component that reacted with FUM20 has an N-terminal amino acid sequence of DSPSVEKNAP.〈section xml:id="abs1-5"〉〈title type="main"〉ConclusionFive monoclonal antibodies against different epitopes of the serine proteinase major allergens in prevalent Penicillium and Aspergillus species were generated in the present study. Antibodies obtained may be useful in the characterization and standardization of serine proteinase allergens in crude fungal extracts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2222.2000.00922.x
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  • 6
    Electronic Resource
    Electronic Resource
    Down-Regulation of Osteoblastic Cell Differentiation by Epidermal Growth Factor Receptor (2000)
    Springer
    Calcified tissue international 67 (2000), S. 141-150 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Osteoblast — Differentiation — Epidermal growth factor receptor — Bone matrix.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The role of epidermal growth factor receptors (EGF-R) in osteogenic cell differentiation was investigated using preosteoblastic MC3T3-E1 (MC3T3) cells and osteoblast-like ROS 17/2.8 (ROS) cells. When cultured in the presence of β-glycerophosphate (GP) and ascorbic acid (AA), MC3T3 cells underwent spontaneous differentiation into osteoblasts which was confirmed as they expressed osteoblast markers such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). Interestingly, the number of EGF-binding sites decreased during their differentiation into osteoblasts, and the osteogenic protein-1 (OP-1) treatment, which accelerated their differentiation, lowered the number of EGF-binding sites even further. On the other hand, ROS cells with high expression levels of osteoblast markers and no EGF-R, after being transfected with human EGF-R cDNA (EROS cells), expressed numerous EGF-binding sites as well as EGF-R mRNA and protein; in the process, they ceased to express osteoblast markers, indicating their dedifferentiation into osteoprogenitor cells. Both MC3T3 and EROS cells showed increased cell growth in response to EGF, whereas ROS cells did not. These results imply that the EGF/EGF-R system in osteogenic cells has a crucial function in osteoblast phenotype suppression and osteogenic cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00223001128
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  • 7
    Electronic Resource
    Electronic Resource
    Hyperprolinaemia in patients with deletion (22)(q11.2) syndrome (2000)
    Springer
    Journal of inherited metabolic disease 23 (2000), S. 847-848 
    Details
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026773005303
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