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  • 1
    Electronic Resource
    Electronic Resource
    Effects of dephasing and vibronic structure on the first hyperpolarizability of strongly charge-transfer molecules (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 1917-1924 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The dispersion of the first molecular hyperpolarizability β of strongly charge-transfer chromophores is investigated. The investigation extends the well-known Oudar–Chemla nonresonant two-level model into the resonant regime. An equation for β that includes the effect of dephasing and vibrational structure of electronic states is derived. It is shown that if only the dephasing mechanism is included in the two-level model, the intrinsic hyperpolarizability β0 calculated using the Oudar–Chemla equation from the hyper-Rayleigh scattering (HRS) experimental data will decrease with decreasing the excitation wavelength. The trend is reversed when the vibrational structure is also incorporated. It is concluded that in order to obtain a consistent β0 in the HRS experiment using an excitation wavelength in the resonance regime, it is inadequate to include only the dephasing mechanism. The vibronic structure also plays an important role and needs to be considered in the data analysis in order to obtain a β0 to agree with the off-resonance experimental result. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.480754
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  • 2
    Electronic Resource
    Electronic Resource
    Cathodoluminescence analysis of cleaved facets of a ZnSe p–n junction (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 3823-3828 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: ZnSe diodes grown on (100) GaAs substrates by molecular beam epitaxy were investigated using cathodoluminesence (CL) measurements at sample temperatures between 50 and 300 K. The CL line scans at different photon energies were performed on cleaved p–n junctions at 50 and 300 K, respectively. Taking into account surface recombination, carrier generation volume, carrier diffusion and internal built-in electric field and related carrier drift, the CL measurements from cleaved p–n junctions could be qualitatively explained. The charge depletion layer has a strong influence on the CL measurements. The calculated charge depletion width is in good agreement with CL measurements. The experimental data from the spatially resolved CL on the cleaved ZnSe diodes revealed important information of the carrier dynamics and recombination processes in these devices. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372420
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  • 3
    Electronic Resource
    Electronic Resource
    Correlation between surface step structure and phase separation in epitaxial GaInAsSb (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 2077-2079 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A strong correlation between the surface step structure and phase separation in metastable GaInAsSb epitaxial layers grown by organometallic vapor-phase epitaxy is reported. The full width at half maximum (FWHM) of the 4 K photoluminescence (PL) peak energy is used as a semiquantitative measure of the degree of phase separation: FWHM values increase with phase separation. The step structure of GaInAsSb grown at 525 °C is vicinal, while it is step bunched for layers grown at 575 °C. The corresponding 4 K PL FWHM data indicate smaller FWHM values for layers grown at the lower temperature, and suggest a lower degree of phase separation. Extreme PL broadening is associated with an aperiodic surface structure. Furthermore, the PL FWHM values decrease when the growth rate increases from 1.2 to 5 μm/h. It is proposed that longer adatom lifetimes, which are associated with longer terrace lengths of a step-bunched surface compared to a vicinal one, allow more time for the adatoms to reach equilibrium and thus phase separate. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126260
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  • 4
    Electronic Resource
    Electronic Resource
    Hypoxia during upper gastrointestinal endoscopy with and without sedation and the effect of pre-oxygenation on oxygen saturation (2000)
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 55 (2000), S. 0 
    Details
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In Study A, the incidence of arterial oxygen desaturation was studied using pulse oximetry (Sao2) in 100 sedated and 100 nonsedated patients breathing room air who underwent diagnostic upper gastrointestinal endoscopy. Hypoxia (Sao2 92% or less of at least 15 s duration) occurred in 17% and 6% of sedated patients and nonsedated patients, respectively (p 〈 0.03). Mild desaturation (Sao2 94% or less and less than 15 s duration) occurred in 47% of sedated patients compared with 12% of nonsedated patients (p 〈 0.001). In Study B, the effects of supplementary oxygen therapy and the effects of different pre-oxygenation times on arterial oxygen saturation (Sao2) in sedated patients were studied using pulse oximetry. One hundred and twenty patients who underwent diagnostic upper gastrointestinal endoscopy with intravenous sedation were studied. Patients were randomly allocated to one of four groups: Group A (n = 30) received no supplementary oxygen while Groups B–D received supplementary oxygen at 4 l.min−1 via nasal cannulae. The pre-oxygenation time in Group B (n = 30) was zero minutes, Group C (n = 30) was 2 min and Group D (n = 30) was 5 min before sedation and introduction of the endoscope. Hypoxia occurred in seven of the 30 patients in Group A and none in groups B, C and D (p 〈 0.001). We conclude that desaturation and hypoxia is common in patients undergoing upper gastrointestinal endoscopy with and without sedation. Sedation significantly increases the incidence of desaturation and hypoxia. Supplementary nasal oxygen at 4 l.min−1 in sedated patients abolishes desaturation and hypoxia. Pre-oxygenation confers no additional benefit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2044.2000.01520.x
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  • 5
    Electronic Resource
    Electronic Resource
    Differences in size and growth rates of male and female migrating Japanese eels in Pearl River, China (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 57 (2000), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The Sr/Ca ratios in otoliths of silver Japanese eels Anguilla japonica, in Pearl River, China, indicated that both sexes did not stay in brackish water and grew in fresh water from the glass eel stage until spawning migration. This did not support the hypothesis that females tended to distribute upstream and males might be restricted to estuaries. The back-calculated total length of males at glass eel stage was not significantly different from that of females, indicating that the hypothesis that small glass eels became males and larger ones became females may not be true. The mean (±S.D.) age and total length of males at migration were 6·4±1·6 years and 48·3±4·5 cm, which were significantly smaller than for females, 8·3±1·6 years and 61·4±4·1 cm. The age of migration was related inversely to growth rate for both sexes. Growth parameters of the von Bertalanffy growth equation were K=0·21 cm year°1, L∞=55·7 cm and to=-0·55 year for males and K=0·14 cm year−1, L∞=77·5 cm and to=-0·60 year for females. The difference in asymptotic length (L∞) between males and females may be because females postpone migration to achieve larger size for maximizing reproductive success.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2000.tb00484.x
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  • 6
    Electronic Resource
    Electronic Resource
    Protein Extraction From Chicken Myofibrils Irrigated with Various Polyphosphate and NaCl Solutions (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 65 (2000), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Physical changes in chicken gastrocnemius myofibrils incubated in 0.1 to 1.0 M NaCl solutions with or without 10 mM ortho-(P), pyro-(PP), tripoly-(TPP) or hexameta- (HMP) phosphate at pH 6.0 were examined by phase-contrast microscopy, electrophoresis, and solubility. PP and TPP performed similarly in promoting protein extraction, P had no apparent effect, and HMP exhibited an intermediate effect. PP, TPP, and HMP treatments markedly improved protein solubility in 0.3 and 0.4 M NaCl through the release of myosin, but the phosphate effect diminished in ≥ 0.6 M NaCl. Overall, phosphates influenced the ultrastructure of myofibrils and extraction of their constituents in the order: PP ∼ TPP 〉 HMP 〉 P ∼ nonphosphate control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2000.tb15962.x
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  • 7
    Electronic Resource
    Electronic Resource
    Nocardiosis in sea bass, Lateolabrax japonicus, in Taiwan (2000)
    Oxford, UK : Blackwell Science Ltd
    Journal of fish diseases 23 (2000), S. 0 
    Details
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: An epizootic in pond cultured sea bass, Lateolabrax japonicus, was caused by Nocardia sp. in Taiwan, in September and October 1997. The cumulative mortality within 1 month was 17.5% (3500 out of 20 000 fish) and diseased fish were 7 months old with total lengths from 25 to 30 cm. Multiple, yellowish white nodules, 0.1–0.2 cm in diameter, were scattered in the gill, heart, liver, spleen and kidney. Histopathologically, typical granulomatous lesions appeared in those organs. The morphology of isolated bacteria from brain heart infusion (BHI) medium or Lowenstein–Jensen medium (LJM) were bead-like filaments, as shown by Ziehl-Neelsen's (ZN) staining method. The gross lesion and histopathological changes found in experimentally infected fish were similar to those in naturally infected fish. Based on the growth characteristics, morphological and biochemical properties of the bacterium, and histopathological changes, the isolated bacteria were identified as Nocardiaseriolae. This is the first report of N. seriolae-infected sea bass in aquaculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2761.2000.00217.x
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  • 8
    Electronic Resource
    Electronic Resource
    Fatigue crack closure analysis of bridged cracks representing composite repairs (2000)
    Oxford, UK : Blackwell Science Ltd
    Fatigue & fracture of engineering materials & structures 23 (2000), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This article presents an analytical and numerical study of the fatigue crack-closure behaviour of a bridged crack representing a crack that has been repaired by a composite patch. It is shown that, provided that the plate stress beneath the patch is less than 40% of the material’s yield stress, the crack-closure stress of a patched crack is approximately equal to that of an unbridged crack under small-scale yielding, depending only on the stress ratio. Furthermore, it is shown that the transient crack-closure behaviour of a patched crack subjected to variable amplitude loading can be determined by analysing an unpatched crack subjected to the same stress intensity factor history. Based on these findings, it is proposed that the fatigue crack closure of a patched crack can be determined by analysing an unpatched centre crack subjected to an adjusted stress, for which an explicit expression is given. Predictions based on the proposed method are shown to correlate very well with experimental results obtained under two aircraft loading spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-2695.2000.00318.x
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  • 9
    Electronic Resource
    Electronic Resource
    Gelation Characteristics of Paddlefish (Polyodon spathula) Surimi Under Different Heating Conditions (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 65 (2000), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gelation properties of paddlefish surimi were investigated with different heating procedures. Without pre-incubation, gel strength of paddlefish surimi increased as temperature increased from 40 to 60 °C. Pre-incubation at 40 °C caused myosin degradation and reduced gel strength by 55% compared to the control. Pre-incubation at 70 °C followed by cooking at 90 °C produced gels with maximum strength. Isothermal heating between 40 and 50 °C produced rheological transitions between 0 and 15 min. Beef plasma powder reduced myosin degradation and enhanced gelation of surimi incubated around 40 °C. These results indicated that the gel-weakening phenomenon in paddlefish surimi was due to the degradation of myosin by some endogenous protease(s).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2000.tb16014.x
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  • 10
    Electronic Resource
    Electronic Resource
    Occurrence of the semi-catadromous European eel Anguilla anguilla in the Baltic Sea (2000)
    Springer
    Marine biology 137 (2000), S. 93-98 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Strontium (Sr) and calcium (Ca) contents in the otoliths of yellow and silver European eels [Anguilla anguilla (L.)] collected from coastal waters of the Baltic Sea and a freshwater lake in Sweden were examined by wavelength dispersive X-ray spectrometry with an electron microprobe. The mean Sr/Ca ratios from elver check to otolith edge were significantly higher for the eels from coastal waters (5.39 ± 1.09‰) than for those from the lake (0.71 ± 0.89‰). The evidence indicates that European eels in the Baltic Sea do not necessarily migrate into freshwater streams during the growth phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270000330
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