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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Abdominal imaging 23 (1998), S. 266-274 
    ISSN: 1432-0509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess and biosystems engineering 6 (1990), S. 49-61 
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effect of NH4Cl addition on intracellular pH (pH i ) was determined by flow cytometric measurements of the fluorescence of a pH-sensitive dye. The effects of NH4Cl on growth were determined for batch growth of cells in flasks in an incubator. The addition of NH4Cl caused a cytoplasmic acidification. A new lower steady-state value of pH i was attained within 20–40 min of NH4Cl addition. A correlation was found between the effects of NH4Cl on growth and on pH i : whereas 3 mM NH4Cl had little effect on growth and on pH i , 10 mM NH4Cl caused a substantial growth inhibition and a pH i decrease of 0.2–0.3 units. The effects of NH4Cl on growth and on pH i were found to be independent of the external pH value (pH e over the range 6.8 to 7.6, except that 10 mM NH4Cl was more toxic at pH e 7.6. The addition of NH4Cl caused an increase in the average cell volume at pH e 7.6, but had no effect on the average cell volume at pH e 's 6.8 and 7.2. For comparison, the effects of pH e alone on growth and on pH i were determined. There was little difference in cell growth at pH e 's 6.8, 7.2 and 7.6. At pH e 6.6, there was a substantial growth inhibition. Some measurements of the effects of pH e on pH i were made, although the steady-state value of pH i as a function of pH e was not determined due to limitations in the pH i -measuring technique. These measurements showed that pH i remained constant from pH e 7.6 to 6.8, but fell by 0.2 units at pH e 6.6, in agreement with the growth results.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effects of dissolved oxygen concentration on hybridoma cell growth, metabolism, and antibody production were studied. A mouse hybridoma cell line producing an IgG1 directed at a consensus α-interferon was grown in batch cultures in a 5 dm3 stirred bioreactor at dissolved oxygen (DO) concentrations of 5, 30, 90 and 95% or air saturation. High oxygen tension (95% of air saturation) reduced specific growth rate without affecting cell viability. At lower dissolved oxygen levels, specific growth rates were approximately independent of DO, although changes in mitochondrial function and antibody production were observed. Flow cytometry assays of a fluorescent mitochondria-specific marker (Rhodamine 123) show significant single-cell heterogeneities during late exponential growth and greater average fluorescence in cultures grown at 95% DO. The quantity of cell-surface immunoglobulin, measured by an immunofluorescent flow cytometric technique, was the same at high (95%) and low (5%) dissolved oxygen concentrations. Myeloma cells of the type used in constructing the above hybridoma line were much less sensitive to dissolved oxygen level. Specific respiration rate, pyruvate utilization rate, cytochrome oxidase activity, and succinate-cytochrome c oxidoreductase activity were significantly greater (62–116%) for the hybridoma cells than for the myeloma cells in T-flask cultures.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 589 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 3369-3387 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Particle-in-cell simulations of applied-B ion diodes using the QUICKSILVER code [D. B. Seidel et al., in Proceedings of the Europhysics Conference on Computational Physics, Amsterdam, 1990, edited by A. Tenner (World Scientific, Singapore, 1991), p. 475] have been augmented with Monte Carlo calculations of electron–anode interactions (reflection and energy deposition). Extraction diode simulations demonstrate a link between the instability evolution and increased electron loss and anode heating. Simulations of radial and extraction ion diodes show spatial nonuniformity in the predicted electron loss profile leading to hot spots on the anode that rapidly exceed the 350 °C–450 °C range, known to be sufficient for plasma formation on electron-bombarded surfaces. Thermal desorption calculations indicate complete desorption of contaminants with 15–20 kcal/mole binding energies in high-dose regions of the anode during the power pulse. Comparisons of parasitic ion emission simulations and experiment show agreement in some aspects, but also highlight the need for better ion source, plasma, and neutral gas models. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed a new ion pinhole camera to obtain energy density profiles of a focused multiterawatt ion beam as a function of ion energy. Beam ions that are elastically scattered from a thin gold foil are imaged through six baffled pinholes onto six separate areas of a sheet of CR-39 nuclear track detector. Each of the areas is covered by an aluminum range filter and records an image with a different lower bound on the ion energy. Subtracting images with adjacent cutoff energies results in images with upper and lower bounds on the ion energy. Ion images are read from the CR-39 with VERA, a fully automatic, image-processor-based nuclear track counting system. Images of the Particle Beam Fusion Accelerator-II (PBFA-II) proton beam have been obtained and show that the beam has been focused to achieve a horizontal FWHM of 5.7 mm and has delivered 9 kJ/cm2 to a target.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1369-1600
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract A study of 13 male opiate addicts was undertaken to investigate the feasibility of transferring abruptly from methadone maintenance treatment to buprenorphine in an outpatient setting. The mean age of subjects was 30 years (range 18-45) and all fulfilled DSM-III-R criteria for opioid dependence. All were maintained on a methadone dose of 20-30 mg mixture daily and were transferred for 3 days to 4 mg buprenorphine sublingually 24-26 hours after their last dose of methadone. On day 1 repeated measures of drug effects were performed, including agonist and withdrawal effects, and this was complemented by saccadic eye movements, a potential new measure of central opioid effects. These recordings were repeated once on days 2 and 3 and the subjects returned to their previous dose of methadone on day 4. Buprenorphine caused no detectable agonist effects or drug “high”, but had “good” effects, was “liked” and well tolerated, suggesting that subjects would comply with buprenorphine treatment despite the lack of reinforcing effects. A mild increase in subjective withdrawal symptoms, which was not clinically significant, was seen in association with an increase in saccadic peak velocity on day 2 of the study but no withdrawal occurred on the other days, indicating that the abrupt transfer technique was acceptable.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Present-day Z-pinch experiments generate 200 TW peak power, 5–10 ns duration x-ray bursts that provide new possibilities to advance radiation science. The experiments support both the underlying atomic and plasma physics, as well as inertial confinement fusion and astrophysics applications. A typical configuration consists of a sample located 1–10 cm away from the pinch, where it is heated to 10–100 eV temperatures by the pinch radiation. The spectrally-resolved sample-plasma absorption is measured by aiming x-ray spectrographs through the sample at the pinch. The pinch plasma thus both heats the sample and serves as a backlighter. Opacity measurements with this source are promising because of the large sample size, the relatively long radiation duration, and the possibility to measure opacities at temperatures above 100 eV. Initial opacity experiments are under way with CH-tamped NaBr foil samples. The Na serves as a thermometer and absorption spectra are recorded to determine the opacity of Br with a partially-filled M-shell. The large sample size and brightness of the Z pinch as a backlighter are also exploited in a novel method measuring re-emission from radiation-heated gold plasmas. The method uses a CH-tamped layered foil with Al+MgF2 facing the radiation source. A gold backing layer that covers a portion of the foil absorbs radiation from the source and provides re-emission that further heats the Al+MgF2. The Al and Mg heating is measured using space-resolved Kα absorption spectroscopy and the difference between the two regions enables a determination of the gold re-emission. Measurements are also performed at lower densities where photoionization is expected to dominate over collisions. Absorption spectra have been obtained for both Ne-like Fe and He-like Ne, confirming production of the relevant charge states needed to benchmark atomic kinetics models. Refinement of the methods described here is in progress to address multiple issues for radiation science. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The CR-39/range-filter technique measures ion energy by determining the maximum filter thickness which ions can penetrate. CR-39 located behind the filter records the ions. This method is used to measure peak voltage in pulsed power accelerators. We investigated range and straggling effects in this diagnostic by exposing it to 8- and 15-MeV protons for both Al and Ta filters. The range agreed with published values to better than ±6%. The range straggling decreased for higher incident ion energy and lower atomic number, as expected, although there were differences up to a factor of 1.7 between the experimental values and predictions. The dependence of the track diameter distribution on ion energy enabled us to establish a signature which is characteristic of ions which penetrate a filter, via straggling. These results can be used to evaluate the errors present when this diagnostic is used to measure accelerator voltage.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: During the past year we have conducted a series of PBFA II target experiments. The design of the experiments was threefold: to characterize the response of targets to ion beams, develop our experimental diagnostic capability, and benchmark our theoretical ability to design and predict the response of the experimental diagnostics to ion-beam-heated, ICF targets. We present here an analysis of spherical exploding pusher experiments. The targets were 6-mm-diam, 100-μm-thick, Cl-doped CH spheres, filled with 1.2 atm of deuterium doped with 7 Torr of H2S. The diagnostics included XRDs, x-ray pinhole, framing, and streak cameras, and a spatially resolved, x-ray crystal spectrometer. Our analysis includes comparisons between experimental results and theoretical predictions of diagnostics responses and sulfur line emission from the compressed target using one- and two-dimensional radiation/hydrodynamic code runs. This work supported by the U. S. Department of Energy under Contract No. DE-AC04-76-DP00789.
    Type of Medium: Electronic Resource
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