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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 4231-4239 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the alternating current plasma display panel, a widespread discharge can take place accidentally in a large number of cells in the upper or lower panel ends. The undesirable discharge is referred to as global breakdown. This is a serious problem, with consequences not only for display quality, but also for product reliability. The mechanism of the global breakdown was examined experimentally using a surface electrometer and theoretically using plasma simulation. From these examinations, the global breakdown mechanism was clarified as follows. Global breakdown was accompanied by charge separation in the horizontal direction of the panel. This charge separation was caused by electron transport downward in the panel during the address discharge. The electron transport formed a negative wall charge on the phosphor surface. When the wall voltage exceeded the insulation voltage of the protective layer, global breakdown occurred. Furthermore, it was clarified that increasing the front dielectric thickness or reducing the back dielectric thickness could suppress the electron transport during the address discharge. These optimizations of cell geometry could eliminate the global breakdown. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 6216-6223 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A plasma discharge due to a sustaining pulse of an alternating current plasma display panel was analyzed using a two-dimensional particle-in-cell code, and basic characteristics of the plasma discharge were calculated. The characteristics of the plasma discharge due to a sustaining pulse are as follows. (i) A large amount of space charge remained after drawing the discharge current. This excess space charge did not contribute to wall charge formation or ultraviolet radiation. (ii) The electron energy distribution function was evaluated and could be well fitted by the Druyvesteyn distribution in the high-energy region. The Druyvesteyn distribution was a consequence of the cross section for electron-Ne elastic scattering. (iii) The calculated ultraviolet radiation efficiency η of the plasma discharge due to a sustaining pulse was between 5.51% and 30.7%. Examination of the sensitivity of the efficiency to the electron temperature showed that reducing the electron temperature was a key to improving the efficiency. (iv) A detailed understanding of the conditions for a stable plasma discharge, memory margin, firing voltage, and electrode voltage of the sustaining pulse were obtained from the voltage transfer curve. The voltage transfer curve could be used to optimize the discharge cell design. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 7097-7099 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of hyperfine interactions has been studied by means of Mössbauer spectroscopy for rapidly quenched amorphous Fe92Zr8 in as-quenched and partially crystallized states. An analysis of the temperature dependence of the mean hyperfine field based on the molecular-field approximation showed that the Curie temperature of the residual intergranular amorphous phase (TCam) is 330±5 K, well above the maximum Curie temperature in amorphous Fe–Zr binary alloys (TC*(approximate)280 K). The difference of TCam−TC* (ΔTCam(approximate)50 K) cannot be attributed to the possible magnetovolume effect in the sample. The difference of ΔTCam could be explained by an enhancement of the molecular field by ∼50 T at 0 K, induced by the Fe exchange field penetrating from the bcc-Fe nanocrystallites. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3615-3617 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have taken magnetic-field images in a wide temperature range of 4–90 K for square-shaped NdBa2Cu3Oy (Tc=89–92 K) thin-film patterns with an array of slots and a linewidth of 4–40 μm by using a scanning superconducting quantum interference device microscope. The thin-film patterns were cooled below 10 K in a various ambient magnetic field of 0.5–100 μT to investigate the behavior of flux trapping. The number of trapped flux quanta clearly decreases with decreasing the ambient field and the linewidth, and flux quanta are completely excluded from the patterns below the threshold-field strength, which agrees well with the Clem's criterion [E. Dantsker, S. Tanaka, and J. Clarke, Appl. Phys. Lett. 70, 2037 (1997)]. Moreover, additional flux trapping in the pattern-edge regions is observed by applying a field above 50 μT at temperatures near 77 K. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    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: Regulation of fluoride release from restorative resin or sealant is beneficial to patients as it will prevent the occurrence of the secondary caries. In this study, we evaluated whether or not the formation of a hydrophobic polysiloxane layer on the surface of the fluoride compound could contribute to the regulation of fluoride release from resin. First, sodium hexafluorosilicate (Na2SiF6) powder was treated with γ-methacryloxypropyltrimethoxysilane (γ-MPTS) and analysed with scanning electronmicroscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR) and electron spectroscopy for chemical analysis (ESCA). Analysis revealed that a hydrophobic polysiloxane layer was formed on the surface of Na2SiF6 powder. Heat treatment commonly used during γ-MPTS treatment was not necessary for the polysiloxane layer formation on the surface of Na2SiF6 powder. Then Na2SiF6 powder treated with γ-MPTS was loaded in bis-GMA/TEGDMA resin, immersed in distilled water and fluoride release was measured using a fluoride electrode. We found that the rate of fluoride release was significantly lower from the resin containing Na2SiF6 powder treated with c-MPTS. We concluded, therefore, that c-MPTS treatment and the resulting hydrophobic polysiloxane layer formation are very effective for the regulation of fluoride release from resin.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Journal of oral rehabilitation 28 (2001), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To elucidate the nature of dentine hypersensitivity, the effects of plaque control on the patency and occlusion of dentinal tubules were investigated systematically in situ using human dentine slabs embedded in partial dentures. The dentine slabs were divided into three groups. In group I, the dentine slabs were kept in an oral cavity without plaque control. In group II, plaque was removed mechanically by brushing. Plaque control was carried out chemically using chlorhexidine in group III. After being kept in the oral cavities for 1, 2 and 3 weeks, the slabs were removed from the partial denture, followed by SEM observation to determine the morphological changes of the dentinal tubules. When no attempt was made to remove plaque, the diameter of tubule orifices increased to 390% of the original values within 3 weeks. In contrast, dentinal tubules were found to be occluded, i.e. the tubule orifices became 〈20% of the original value within 1 week when plaque control efforts were made, using either method of plaque control. We conclude that plaque control plays one of the key roles in the patency versus occlusion of dentinal tubules, and thus in the aetiology and natural reparative process of dentine hypersensitivity.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 20 (2004), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : The gastric mucosal alcohol dehydrogenase activity was reported to be reduced in subjects with Helicobacter pylori-associated chronic gastritis. However, the role of H. pylori infection in the metabolism of ingested ethanol has not been fully elucidated.Aim : To clarify whether H. pylori infection exerts any influence on the metabolism of small amounts of ethanol in humans.Subjects and methods : 13C-ethanol (100 μL) diluted in 100 mL water was administered orally to 22 healthy volunteers before breakfast. Breath samples were then collected every 10 min for up to 60 min. The content of 13CO2 (‰) was analysed using a mass-spectrometric method. The excretion rate of labelled CO2 was analysed by calculation of the following mathematical parameters, i.e., Tmax, Cmax, and AUC60.Results : In H. pylori-negative controls (n = 11), the Tmax, Cmax and AUC60 were 0.47 ± 0.13, 19.1 ± 6.0 and 13.7 ± 4.5, respectively. The corresponding values were 0.53 ± 0.16 (n.s.) and 12.7 ± 4.8 (P 〈 0.05) and 9.0 ± 3.6 (P 〈 0.05), respectively, in subjects with H. pylori infection (n = 11). Successful eradication of H. pylori was associated with significant increase of these parameters (Cmax and AUC60, n = 6).Conclusions : The metabolism of small amounts of ethanol is attenuated in subjects with H. pylori infection.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Although Helicobacter pylori infection is now acknowledged as a major promoter of gastric cancer in humans, the carcinogenetic process of this effect has not been fully elucidated. Precancerous lesions such as intestinal metaplasia, enhanced proliferation of epithelial cells and elevated level of growth factors have been postulated to play a role.Aim : To analyse a relationship between gastric mucosal proliferation, mucosal content of hepatocyte growth factor and prevalence of intestinal metaplasia before and after successful H. pylori eradication therapy.Methods : We evaluated 25 H. pylori-eradicated patients. At initial endoscopic examination, two biopsy tissue samples each were obtained from the antrum and great curvature of the corpus. Tissue content of hepatocyte growth factor and neutrophil myeloperoxidase were measured using an ELISA method, and histological assessment of intestinal metaplasia (haematoxylin and eosin) and proliferating cells (Ki-67 immunostaining) was performed. The patients were treated with a 1-week course of triple therapy. At 10 months after successful eradication, biochemical and histological assessments were repeated.Results : Among all patients (n = 25), no intestinal metaplasia was detected in the corpus mucosa, but was observed in 10 patients (40%) in the antrum. This prevalence ratio was not changed after eradication. A slight decrease in HGF content was demonstrated in both sites, but the level of antral hepatocyte growth factor was significantly decreased in patients with intestinal metaplasia but not in those without. Proliferative index (Ki-67 positive cells/epithelium) was decreased after eradication therapy in both sites. An increase in proliferative index was observed in the antrum with intestinal metaplasia compared with that without, which significantly decreased after eradication therapy.Conclusions : H. pylori eradication therapy in the present study afforded an inhibitory effect on epithelial cell proliferation and on the mucosal content of HGF.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : There is a lack of evidence for the efficacy of preventive medications for peptic ulcers (PUs) among long-term users of non-steroidal anti-inflammatory drugs (NSAIDs) in Japan.Aim : To estimate the preventive effect by normal dose, not high-dose histamine-H2 receptor antagonists (H2RA) for NSAID-induced ulcers.Methods : We designed two different studies to assess the efficacy of anti-ulcer agents in rheumatoid arthritis (RA) in patients treated over a long term with NSAIDs. An investigative survey divided patients into those not taking anti-ulcer agents (non-medication group); those taking mucosal protective agents (mucosal protectant group), H2RA (H2RA group), proton pump inhibitors (PPI group), or a prostaglandin E1 analog (PG) (PG group). The second study compared prospectively the preventive effects of either famotidine 20 mg bd (famotidine group) or lansoprazole 15 mg daily (lansoprazole group) in patients with PU scars.Results : The prevalence of PU in the H2RA group was significantly lower compared to the mucosal protectant group (P 〈 0.05), and the mucosal protectant group was not significantly different to the non-medication group. The prospective study revealed that the PU onset rate of the famotidine group was 8% (1/13), and lansoprazole group was 15% (2/13), indicating no significant differences between the two.Conclusions : In Japan, normal-dose H2RA is expected to be a new PU preventive treatment strategy in patients requiring long-term NSAID therapy.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 14 (2000), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aim: To investigate the EP receptor subtype involved in the gastroprotective action of prostaglandin (PG) E2 using various EP receptor agonists in rats, and using knockout mice lacking EP1 or EP3 receptors. Methods: Male SD rats and C57BL/6 mice were used after an 18-h fast. Gastric lesions were induced by oral administration of HCl/ethanol (150 m m HCl in 60% ethanol). Rats were given various EP agonists i.v. 10 min before HCl/ethanol: PGE2, sulprostone (EP1/EP3 agonist), butaprost (EP2 agonist), 17-phenyl-ω-trinorPGE2 (17-phenylPGE2: EP1 agonist), ONO-NT012 (EP3 agonist) and 11-deoxyPGE1 (EP3/EP4 agonist). In a separate study, the effect of PGE2 on HCl/ethanol lesions was examined in EP1- and EP3-receptor knockout mice. Results: Gastric lesions induced by HCl/ethanol were dose dependently prevented by PGE2; this effect was mimicked by sulprostone and 17-phenylPGE2 and was significantly antagonized by ONO-AE-829, an EP1 antagonist. Neither butaprost, ONO-NT012 nor 11-deoxyPGE1 exhibited any protective activity against HCl/ethanol-induced gastric lesions. PGE2 caused an inhibition of gastric motility as well as an increase of mucosal blood flow and mucus secretion, the effects being mimicked by prostanoids activating EP1 receptors, EP2/EP3/EP4 receptors and EP4 receptors, respectively. On the other hand, although HCl/ethanol caused similar damage in both wild-type mice and knockout mice lacking EP1 or EP3 receptors, the cytoprotective action of PGE2 observed in wild-type and EP3-receptor knockout mice totally disappeared in mice lacking EP1 receptors. Conclusion: The gastric cytoprotective action of PGE2 is mediated by activation of EP1 receptors. This effect may be functionally associated with inhibition of gastric motility but not with increased mucosal blood flow or mucus secretion.
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