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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 4164-4167 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Observations of a vacuum spark discharge are presented using a coaxial line driver. A 120 ns, 1.5 Ω coaxial line is used to give peak discharges of 90 kA. The usual line spark gap is shorted out giving a new mode of operation. The discharge is initiated once the rising sinusoidal voltage is applied by focusing a Nd:YAG laser onto the cathode front surface, peak current is reached at 250 ns after this. Reproducible hot spot formation is observed at this time. Holographic interferometry combined with time and space resolved x-ray observations show emission from a dense anode plasma as well as from the dense plasma column in which hot spot forms at peak current.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 3910-3916 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental observations are presented of a vacuum spark driven by a low impedance pulse forming line delivering 100 kA to the load. A pulsed laser is used to form a preionizing plasma on the cathode. The combination of axial and radial optical streak camera observations, together with the time and space resolved soft x-ray emission, permit the evolution of the plasma dynamics, density and temperature to be measured. Three kinds of behavior are observed according to axial position. A close correlation is found between the x-ray and the optical emission, with the observation of micropinch formation. A discussion is presented in which the behavior of the vacuum spark under differing operating conditions is compared. © 1995 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)
    Review of Scientific Instruments 64 (1993), S. 3330-3331 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The design of a fast multiframe holographic interferometry system for rapidly evolving transparent objects is described. Essential elements to the configuration are a multipulse laser, an electro-optic deflector (EOD), and a concave spherical mirror. The hologram, EOD and concave mirror are in a circle whose radius is the same as the spherical mirror. The different frames are superimposed on the same area of the hologram. On reconstruction separation of multiple images is achieved on the Fourier plane of a lens which is used to image the reconstruction of the hologram. The total number of optical components is kept to a minimum and only two of these are used in transmission. Due to the low component count the quality of interferograms obtained is very high.
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  • 4
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 4244-4249 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Comparative observations of the Vacuum Spark discharge are presented under differing electrical drive conditions but identical geometrical conditions. A 1.5 Ω 120 nsec, coaxial line is used to provide maximum currents to 90 kA. The line may be operated in the usual switched mode to give a rectangular voltage and current wave form, or in the Hybrid mode, in which case the voltage builds slowly until breakdown occurs. In both modes of operation the value of dI/dt is about 1×1012 A/sec. A Nd:YAG is focused onto either electrode to initiate the discharge. With the laser focused onto the anode a low-density plasma accompanied by intense electron beams is formed. With the laser focused on the cathode a much higher plasma density is observed in the gap, with the formation of a dense tight pinch close to the cathode, in which hot spots form at peak current. The Hybrid mode is favored for its reproducible behavior.
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  • 6
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An experiment was conducted to study the effect of protein level on the growth rate, survival, pre- and postprandial oxygen consumption, and ammonia (N-NH3) excretion in white shrimp. Penaeus setiferus (L.), juveniles. Diets containing 10%, 20%, 30%, 40% and 50% protein were provided at a proportion of 15% of the dry weight of shrimp weighing 0.19 ± 0.01g. The instantaneous growth rate was recorded for 45 days. The optimum protein level, in terms of the best growth rate, was that of the 30% protein diet (1.1 5g45days−1). All shrimp fed with the diets had significantly higher respiration rates after feeding because of the apparent heat increment (AHI). A greater postprandial nitrogen excretion (PPNE) excretion was also observed after feeding. Shrimp maintained on the 30% protein diet had the lowest AHI and PPNE coefficients (percentage of ingested energyl. and took the least time to reach the oxygen consumption and nitrogen excretion peak. The 0:N ratios varied according to protein level, with higher values (32 and 44, fasting and Feeding, respectively) with a 30% protein diet, and lower values (10 and 13. fasting and feeding, respectively) with 10% and 50% protein diets. These results indicate that P. setiferus juveniles use protein when fed with high (50%) and low (10%) protein diets, and lipid-protein substrates with a 30% protein diet. Under these conditions, P. setiferus grow better with a 30% protein diet where shrimp use food more efficiently.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 51 (1986), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When polyphenoloxidase (PPO) was exposed to sulfite prior to susbstrate addition, inhibition was irreversible. Trials to regenerate PPO activity, using extensive dialysis, column chromatography, and addition of copper salts were not successful. Increased concentrations of sulfite and pH levels less than 5 enhanced the inhibition of PPO by sulfite. At pH 4, concentrations greater than 0.04 mg/mL completely inhibited 1,000 units of PPO activity almost instantaneously. This suggested that the HSO3- molecule was the main component in the sulfite system inhibiting PPO. Column chromatography, extensive dialysis, and gel electrophoresis did not demonstrate 35SO2 bound to purified pear PPO protein. Formation of extra protein bands of sulfite inhibited purified pear PPO fractions on gel electrophoresis was demonstrated. This and other evidence suggested that the major mode of direct irreversible inhibition of PPO was modification of the protein structure, with retention of its molecular unity.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 53 (1998), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The food web in Terminos Lagoon, south-western Gulf of Mexico was dominated by the detrital pathway, with benthic invertebrates playing a significant role in transferring energy from detritus to higher trophic levels. The fish yield per unit of net primary production was only 0.04%. Fractional trophic levels ranged from 1.0 to 3.31, with fish occupying the highest trophic levels. Using network analysis, the system network was mapped into a linear food chain and five discrete trophic levels were found with a mean trophic transfer efficiency of 7%. Analysis of mixed trophic impacts showed that fish had very little impact on the other compartments, due to their relatively low biomass and consumption, with exception of the Engraulidae. Detritus and lower trophic levels had significant positive impacts on other groups in the system, suggesting ‘bottom-up’ control of the food web. A high detritivory: herbivory ratio (4.6: 1) indicated that most of the primary production was recycled through the detritus-based food web. A Finn cycling index of 7% and average path length of 10 were obtained.
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Analytical Biochemistry 162 (1987), S. 301-308 
    ISSN: 0003-2697
    Keywords: ELISA ; fluorescence ; immunoassay ; isopentenyl adenosine ; monoclonal antibody ; zeatin riboside
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 70 (1987), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sixteen monoclonal antibodies against isopentenyl adenosine (iPA) were developed and characterized for reactivity towards this cytokinin and structurally related molecules by use of a competition fluorescence enzyme immunoassay. Antibodies with suitable affinity and specificity were used in an immunoassay to detect and quantify isopentenyl adenosine. Logit/log plots of fluorescence vs pmol of the cytokinin indicated that the assay had a measurement range of 0.03–256 pmol (10–8500 pg) with high linearity (r =–0.98). This competition fluorescence enzyme immunoassay showed that three antibodies cross-reacted with N-6-benzyladenine and its riboside: cross-reactivity with dihydrozeatin and its riboside, cis-zeatin, trans-zeatin riboside, adenine and adenosine was minor. When an immunoaffinity-HPLC technique was used to measure the cross-reactivity of two of the antibodies in the presence of known quantities of multiple cytokinins, iPA was bound in preference to the other cytokinins. One of the antibodies was used to quantify this cytokinin in developing wheat (Triticum aestivum L. cv. Stephens) seeds and in wheat seeds spiked with known amounts of certain other cytokinins. The use of these antibodies in immunoassay in combination with HPCL for quantification of iPA in plant extracts is discussed.
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