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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Heparin, a highly sulfated glycosaminoglycan, is known to be obligatory for long-term endothelial cell cultures; it potentiates the mitogenic activities of endothelial cell growth factors and prolongs the replicative life span of the cells. Here we have shown that besides its growth factor-supportive role, heparin exerts a specific action on cerebral capillary endothelial cells (cECs), unrelated to serum or growth factors, by increasing activity of ornithine decarboxylase (ODC; EC 4.1.1.17) in these cells. For our experiments we have used two different types of cloned cECs: type I cECs, grown in the presence of endothelial cell growth factor and heparin, and type II cECs, usually cultivated without growth factors. Heparin action on ODC activity was shown to be dose dependent within the range of 1–100 μg/ml. Increasing concentrations of or depletion of endothelial cell growth factor from type I cultures had no effect on ODC activity. The increase in enzyme activity was highest after 30 min to 1 h of heparin treatment. As evidenced by northern analysis, the heparin-mediated enhancement of ODC activity was not accompanied by changes of ODC mRNA levels. Studies of DNA replication revealed that in the absence of heparin-binding growth factors, heparin did not affect the proliferative activity of cloned cECs.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 51 (1988), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Intracranial microdialysis was used to measure changes in extracellular amino acids within the rat brain during local osmotic alteration of the extracellular micro-environment or during systemic water intoxication. Increased cellular hydration produced by either of these methods was accompanied by a marked increase in extracellular taurine levels without affecting the other amino acids measured. With local osmotic alteration, this increase was osmolarity dependent and reversible. The specificity, sensitivity, and reversibility of the increase in extracellular taurine strongly suggest a functional role in osmoregulation in the brain under normal as well as pathological conditions.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2879-2883 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Systems for focusing a light ion beam onto an inertial confinement fusion (ICF) target are studied using a thin lens model to compute ion trajectories. Three focusing systems are analyzed. The systems are (1) an uncorrected single focusing lens; (2) a focusing lens with chromatic correction due to the self magnetic field of the beam; and (3) the combination of a focusing lens, a defocusing lens for divergence correction, and chromatic correction from the beam's self field. Systems (2) and (3) both produce energy efficiencies of greater than 50% for transporting an ion beam with 6 mrad divergence over 4 m and focusing it onto a 1 cm radius target. The predictions of the thin lens model are compared to predictions made by codes using numerical integration of particle trajectories. The implications for ICF applications are discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5110-5113 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The band gap and microstructure of Ga0.5In0.5P have been shown to vary with deposition conditions. However, growth on (511)B GaAs substrates has been reported to give Ga0.5In0.5P with band gaps close to that of disordered material. It is shown here, that with appropriate selection of the growth parameters, Ga0.5In0.5P can be grown with low band gap and significant ordering on even the (511)B substrates, implying that surface steps play an important role in the ordering process. For the lattice-matched composition, a band gap of 1.83 eV was obtained using low growth temperature (575 °C), low growth rate (0.55 μm/h), and high phosphine pressure (5 Torr).
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 2515-2519 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present results of Raman scattering from coupled phonon-plasmon modes in Se-doped n-Ga0.52In048P alloy. Due to the small energy separation between the Γ- and the L-point conduction-band minima for this alloy composition, a significant fraction of the free carriers at room temperature are present in the L-conduction-band valley, giving rise to a multicomponent plasma. The carrier concentrations extracted from the Raman spectra for the different epilayers are in good agreement with the free electron concentrations determined by capacitance-voltage measurements. We employ the light scattering technique to extract the carrier concentration in the n-type emitter layer of a GaInP-based solar cell. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 7 (1968), S. 2242-2249 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe the design of an intense, pulsed, repetitive, neutral beam based on magnetically insulated diode technology for injection into ITER for spectroscopic measurements of thermalizing alpha particle and thermal helium density profiles, ion temperature, plasma rotation, and low Z impurity concentrations throughout the confinement region. The beam is being developed to enhance low signal-to-noise ratios expected with conventional steady-state ion beams because of severe beam attenuation and intense bremsstrahlung emission. A 5 GW (e.g., 100 keV, 50 kA) 1 μs duration beam would increase the charge exchange recombination signal by 103 compared to a conventional 5 MW beam. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 4502-4508 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ordered Ga0.52In0.48P alloys (GaInP2 for simplicity) grown on miscut [001] GaAs resemble monolayer superlattices with alternating Ga- and In-rich layers along either the [1¯11] or [11¯1] directions. Recent calculations suggest that, in fully ordered GaInP2, an intrinsic ordering-induced electric field of order 1600 kV/cm should exist. In partially ordered samples, as can actually be grown, the expected field is reduced to 400 kV/cm. For such a strong internal electric field, clear Franz–Keldysh Oscillations (FKOs) would be expected in an electroreflectance measurement. We report electroreflectance measurements of ordered GaInP2 layers measured at T=100 K. For all samples measured, no FKOs are observed in the absence of an additional external dc bias voltage. At the lowest bias voltages for which FKOs are seen, the internal electric field in the GaInP2 layer, determined from the FKOs, is ∼60 kV/cm along the [001] direction corresponding to ∼100 kV/cm along the ordering direction. Hence, we conclude that, at least in the organometallic vapor phase epitaxy grown samples studied here, any net macroscopic internal electric field in the GaInP2 layer is less than ∼100 kV/cm along the ordering direction. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 3418-3425 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have developed a high-purity, intense, lithium ion beam source which operates at 500 kV and 120 A/cm2 with pulse widths of 125 ns full width half maximum. The beams were generated using a lithium chloride anode in planar magnetically insulated geometry. We have found that the combination of vacuum baking of the anode at 250 °C followed by the application of 100 W of pure argon, steady-state, glow discharge cleaning reduced the impurity concentration in the beam to approximately 10% (components other than chlorine or lithium were considered impurities). Although the impurities were low, the concentration of chlorine in the 1+ and 2+ charge states was significant (∼25%). The remaining 65% of the beam consisted of Li+ ions. Without the special cleaning process, over half the beam particles were impurities. It was determined that these impurities entered the beam at the anode surface but came originally from material in the vacuum chamber. After the cleaning process, recontamination was observed to occur in approximately 6 min. This long recontamination time, which was much greater than the expected monolayer formation time, was attributed to the elevated temperature of the anode. We also compared the electrical characteristics of the beams produced by LiCl anodes to those generated by a standard polyethylene proton source. In contrast to the polyethylene anode, the LiCl source exhibited a higher impedance, produced beams of lower ion current efficiency and had longer turn on times.
    Type of Medium: Electronic Resource
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