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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 237-242 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Defects in SiO2 (48 nm)/Si induced by 30 keV Er ion implantation were studied by positron annihilation. Depth-selective information on defects for samples implanted with doses of 3.0×1014 and 1.5×1015 Er/cm2 was obtained by a variable-energy positron beam by measuring Doppler broadening of positron annihilation γ rays as a function of incident positron energy. Comparison of the results by Doppler broadening with those by electron spin resonance after annealing indicates that the types of defects (which predominantly exist in the SiO2 layer) depend on implantation dose. The annealing temperature dependence of positron data is compared with that of the cathodoluminescence intensity at 1.54 μm, and the possible effect of defects on luminescence intensity is discussed. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical & experimental allergy 33 (2003), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Vascular endothelial growth factor (VEGF) is highly expressed in the airway of asthmatic patients. As VEGF increases airway vascular permeability, consequent thickening of the airway wall mucosa may lead to narrowing of the airway lumen.Objective We evaluated the relationship between VEGF levels in induced sputum and eosinophilic inflammatory profiles, and the degree of airway vascular permeability in asthmatic patients and we evaluated the effect of inhaled corticosteroids on VEGF levels in induced sputum.Methods Induced sputum specimens were obtained from 28 glucocorticosteroids free asthmatics and 11 healthy control subjects. We examined VEGF levels and airway vascular permeability index in induced sputum. After the initial sputum induction, 21 asthmatics received 8-week inhaled beclomethasone dipropionate (BDP, 800 µg/day) therapy, then sputum induction was repeated.Results The VEGF levels in asthmatics were significantly higher than in healthy control subjects (P 〈 0.0001). The VEGF levels were negatively correlated with forced expiratory volume of 1 s (FEV1, % predicted, r = − 0.68, P 〈 0.001), the percentage of eosinophils (r = 0.51, P 〈 0.01) and ECP levels (r = 0.39, P 〈 0.05). Moreover, the VEGF levels were significantly correlated with airway vascular permeability index (r = 0.61, P 〈 0.001). After 8-week inhaled BDP therapy, the VEGF levels were significantly decreased compared to pretreatment levels (P 〈 0.0001) and the VEGF levels were significantly correlated with airway vascular permeability index even in post-treatment asthmatics (r = 0.62, P 〈 0.01).Conclusion The VEGF levels in induced sputum were increased in asthmatics and its levels were associated with degree of airway narrowing and airway vascular permeability. These findings provide strong evidence that VEGF may play an important role in the pathogenesis of bronchial asthma.
    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 91 (2002), S. 1704-1706 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Positronium annihilation was applied to characterize the nanoporous structure of thin silicon oxide films sputter-deposited at different argon pressures ranging from 0.1 to 2.0 Pa. At higher argon pressures, the 3γ decay probability of ortho-positronium (o-Ps) was substantially enhanced. A comparison of this result with that obtained for capped samples indicated that: (a) 3γ annihilation is due to the intrinsic decay of o-Ps diffusing out from the film into vacuum and (b) films deposited at high argon pressures contain highly connected, open pores. Positron lifetime spectroscopy measurements on the capped films showed that the characteristic size of the pores can be as large as 2.6 nm, depending on the argon pressure. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow-through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free-running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six-hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 26 (2003), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The effect of abscisic acid (ABA) on the tolerance to oxidative stress in a freshwater green alga, Chlamydomonas reinhardtii, was investigated. Exogenously added ABA enhanced the growth of this alga, which was observed under continuous illumination but not in the dark. The cells treated with ABA for 24 h showed tolerance to oxidative stress caused by exposure to paraquat or hydrogen peroxide. In the ABA-treated cells, the activities of two antioxidant enzymes, catalase (CAT) and ascorbate peroxidase (APX), were significantly higher than those in the untreated control. The result suggests that ABA plays a role in the enhancement of tolerance to oxidative stress by increasing the activity of antioxidant enzymes.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1436-2813
    Keywords: Key Words: chylous cyst, mesentery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 250 (2000), S. 152-155 
    ISSN: 1433-8491
    Keywords: Key words Event related potentials (ERPs) dementia of Alzheimer type (DAT) ; Attention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Electrical field changes of event-related potentials (ERPs) were investigated in 26 patients with dementia of Alzheimer's type (DAT) and 12 age-matched normal subjects. The patients were assessed with the Clinical Dementia Rating and Mini-Mental State. Each patient selected had only mild to moderate mental disability. Auditory oddball stimulation was presented at 1.5 s intervals and 1000 Hz for the nontarget and 2000 Hz for the target tones, both at 85 dB. The target tones were 20% of all the tones. The reference-independent data (latency, global field power: GFP, dissimilarity index: DISS and location of centroids) were obtained and analyzed for each ERP component. The momentary electric strength or ‘hilliness’ of the ERPs landscape was indicated by GFP. The patients showed prolonged latencies and decreased P300 GFP amplitudes and of N100 GFP. These findings suggest that the abnormal electrical field of ERP may reflect abnormal information processing following the attentional process for target stimuli in DAT patients.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 15 (2000), S. 715-722 
    ISSN: 1434-6036
    Keywords: PACS. 45.70.Vn Granular models of complex systems; traffic flow - 05.45.Gg Control of chaos; applications of chaos - 47.62.+q Flow control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The jam phenomenon in traffic flow wastes not only considerable traffic-transportation time but also great amounts of fuel due to many accelerate-decelerate actions. From traffic-economic and traffic-pollution viewpoints, the suppression of traffic jam is an important issue we have to solve. The present paper shows that -norm, which has been used in the field of control theory, can reveal the traffic jam phenomenon in an optimal velocity traffic model under an open boundary condition. Furthermore, we suppress the traffic jam in the model by the decentralized delayed-feedback control method. Some numerical simulations are shown to verify our theoretical results.
    Type of Medium: Electronic Resource
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