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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2273-2275 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the effects of rapid thermal annealing on the electrical and optical properties of planar-doped AlGaAs/InGaAs/GaAs high electron mobility transistor structures grown by molecular beam epitaxy. Hall effect and photoluminescence measurements on samples with In0.22Ga0.78As and In0.28Ga0.72As channels reveal a temperature-dependent degradation in sheet charge density, Hall mobility, and photoluminescence response. The structures were essentially stable through the temperature range used in normal device processing. However, annealing temperatures greater than 700 °C resulted in strain relaxation and layer intermixing, especially for the In0.28Ga0.72As sample.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 3974-3977 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have used pyridine and a number of related molecules to lower the workfunction of thin Ag films so as to compare the effects of various molecular properties on the photoemission process and on surface electronic modes. We find that a nitrogen lone pair electronic orbital is essential for a large threshold shift. Other molecular properties, such as dipole moment and polarizability have a very small effect. The films are rough, therefore we see strong photoyields at the energy of the surface plasma mode, 3.6 eV. There is also a peak in the photoyield at 3.85 eV, the energy of the bulk plasmon.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 31 (2004), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The purpose of this study was to evaluate the polymerization shrinkage of three orthodontic adhesive resins when polymerized with a high-energy plasma arc light (1340 mW cm−2) and a conventional halogen light (500 mW cm−2), and to correlate the polymerization shrinkage with the degree of conversion. To equalize the total light energy delivered to the adhesive resin, irradiation time was varied between 3 or 6 s for a plasma arc-curing unit, and 8 or 16 s for a halogen light-curing unit. The polymerization shrinkage of adhesive resins during the light-curing process was measured using a computer-controlled mercury dilatometer and the degree of conversion was measured using Fourier transform infrared spectroscopy. A plasma arccuring unit produced significantly lower polymerization shrinkage than a halogen light-curing unit when the equivalent total light energy was irradiated to the orthodontic adhesive resins (P 〈 0·05). The magnitude of polymerization shrinkage was significantly different depending on the kind of adhesive resins (P 〈 0·05), but there was no significant correlation between the filler fraction and the polymerization shrinkage (r2 = 0·039). There was strong correlation (r2 = 0·787) between the polymerization shrinkage and the degree of conversion with a halogen light-curing unit, but poor correlation (r2 = 0·377) was observed with a plasma arc-curing unit.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 31 (2004), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light-emitting diodes) and irradiation methods (one-step, two-step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis-GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17·0 J cm−2 (P = 0·05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15·6–17·7 J cm−2), the efficiency of irradiation methods was different by the following order: one-step ≥ two-step 〉 pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 30 (2003), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The objective of this study was to compare the mechanical properties of calcium phosphate cements (CPC) for possible dental applications with varied liquid and powder compositions under the same testing condition. Cements studied in this experiment were divided into two groups of CPC not containing polymer and polymeric CPC (PCPC). Cement powder was formed by combining equimolar amounts of dicalcium phosphate anhydrous and tetracalcium phosphate, or acrylic resin polymer powder mixture. The CPC specimens for the compressive strength (CS) and diametral tensile strength (DTS) measurements were prepared by mixing powder and liquid for 30 s with a powder/liquid ratio of 3:1, and subsequently packing the paste into a brass mould. The specimens were kept at 37 °C and 100% relative humidity for 24 h before measurements were conducted on a Universal Testing Machine with a cross-head speed of 1 mm min–1. The CS of CPC was 0ḃ14–10ḃ29 MPa and that of PCPC was 0ḃ26–117ḃ58 MPa. The DTS of CPC was 0ḃ10–4ḃ56 MPa and that of PCPC was 0ḃ07–22ḃ54 MPa. The CS and DTS were very diverse depending on the composition of powder and liquid. Some compositions showed higher values than commercial liners. Thus compositions of 2% carboxymethyl cellulose + 35% citric acid in phosphate buffered saline (PBS), 20% gelatin in PBS, 2% sodium alginate in PBS, 20–40% aqueous acrylic-maleic copolymer solution, and some of the HPMC and PMVE-Ma solutions exhibited promising formulae for dentine regenerating materials. Acrylic resin-PCPC group showed generally higher CS and DTS values. Based on this study, further studies on the reaction with odontoblast and resultant dentine regeneration should be performed using promising compositions.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 141 (1999), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 148 (2003), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 31 (2004), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The objectives of this study were to determine the influence of thermocycling on the changes of elastic modulus (EM) and colour, and to evaluate cytotoxicity after repeated elution of short-term-use soft liners. Three short-term-use soft liners [soft acrylic-based Coe Comfort (CCM), Coe Soft (CST) and Soft Liner (SFL)], and long-term-use silicone-based Tokuso Soft Liner (TSL) acting as a control were studied. EM was measured at baseline and after thermocycling at 5–55 °C for 500, 1000, 1500 and 2000 cycles. For the colour measurement, specimens in discs 20 mm in diameter and 1 mm in thickness were prepared, attached to a denture base resin plate, and then thermocycled as above. Colour change (ΔE*) was measured according to the Commission Internationale de l'Eclairage (CIE) L*, a*, and b* scale on a spectrophotometer. For the cytotoxicity evaluation, specimens were eluted for 24 h in culture media repeatedly up to four times, and MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed. EM of CCM and CST increased up to 1500 and 1000 cycles of thermocycling respectively. EM of SFL gradually increased up to 2000 cycles, and that of TSL increased after 500 cycles and did not change after then. ΔE* of soft liners after 2000 cycles except CCM were 3·68–8·65. EM increased up to 1000–1500 cycles, and perceivable colour change was observed after 2000 cycles in most materials. Therefore, short-term-use soft liners should be used within a limited time, although the cytotoxicity decreased after repeated elution.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 29 (2002), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The purpose of this study was to determine the effectiveness of polymerization in the newly introduced blue light emitting diode (LED) (Experimental, SNU, Korea), and plasma arc curing (PAC) (Apollo 95E, Elite, DMD, USA) compared with conventional halogen lamp (Spectrum 800, Dentsply, USA). Various irradiation time with fixed intensity of light-curing units (LCUs) were irradiated to produce the same total light energy. The degree of double bond conversion (DC) of three resin composite (shade A3) was measured with a Fourier-transform infrared (FT-IR) spectrophotometer at various depths from the surface. Immediately after exposure to light, 100 μm thickness of resin composite was sectioned at the 1, 2, 3 and 4 mm from the top surface. The infrared spectrum of uncured resin and each wafer specimen were then obtained. The results were as follows: DC was significantly influenced by three variables of material, depth from the surface, and light source and energy level (P 〈 0·01). When the same light energy was irradiated, DC by plasma arc and LED was not significantly different from the halogen lamp (P 〉 0·05). When light energy was increased twice, no significant difference in DC was observed up to 2 mm from the surface (P 〉 0·05), but DC increased significantly from 3 mm (P 〈 0·05).
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Der p 2 isoallergens have been reported and the possibility of different allergenicity has also been suggested. In addition, the quantification with 2-site ELISA may be affected by the isoallergens.Objectives Two different recombinant Der p 2 (rDer p 2) isoallergens were compared in terms of human IgE responses and the reliability of quantification of them with two-site ELISA kits which use monoclonal antibodies (mAbs) as capture and detection of Der p 2.Methods Seven different Der p 2 cDNA from the cultured Dermatophagoides pteronyssinus (DP) were cloned and polymorphism in nine amino acid residues was found. Two different recombinant isoallergens (rDer p 2A and rDer p 2B) were expressed and compared to their human IgE immune responses by ELISA and the ELISA inhibition test with 23 sera of DP-allergic patients. The reliability of quantification of two different available 2-site ELISA kits, which used mAbs for capture and detection of Der p 2, was evaluated.Results The ELISA optical density of rDer p 2B-specific IgE (sIgE) was higher than that of rDer p 2A (P 〈 0.001). The ELISA inhibition curve of rDer p 2B sIgE in pool I sera (n = 5; high sIgE both to rDer p 2A and rDer p 2B) did not show any differences in the 50% inhibition concentration and maximum inhibitory percentage of rDer p 2A and rDer p 2B sIgE. However, with pool II sera (n = 5; markedly higher sIgE to rDer p 2B than rDer p 2A), the 50% inhibitory concentrations (10 µg/mL vs. 40 ng/mL) and maximum inhibitory percentage (61% vs. 99%) of rDer p 2B sIgE with the two recombinant isoallergens were quite different. rDer p 2B could be quantified with two different 2-site ELISA kits, but rDer p 2A was detected by only one kit.Conclusion We conclude that isoallergens of Der p 2 may have different IgE immune responses. Quantification of Der p 2 with 2-site ELISA kits that adopted mAbs, might be affected by the prevalent form of the isoallergens in reservoir dust.
    Type of Medium: Electronic Resource
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