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  • 1
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    Washington : Periodicals Archive Online (PAO)
    Middle East Journal. 3 (1949) 211 
    ISSN: 0026-3141
    Topics: Ethnic Sciences , History , Political Science , Sociology , Economics
    Notes: Economic Reviews
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  • 2
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    Washington : Periodicals Archive Online (PAO)
    Middle East Journal. 4 (1950) 244 
    ISSN: 0026-3141
    Topics: Ethnic Sciences , History , Political Science , Sociology , Economics
    Notes: Economic Reviews
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The release of endogenous 5-hydroxytryptamine (5-HT), substance P (SP), and neurokinin A (NKA) from superfused tissue slices of rat ventral lumbar spinal cord, where SP and NKA coexist with 5-HT in terminals of descending bulbospinal neurons, was investigated. Electrical field stimulation was performed using square-wave pulses of 2-ms duration and 30 mA stimulus intensity. The following four different patterns of stimulation were used: 2 Hz continuous, 20 Hz continuous, 20 Hz intermittent, and 50 Hz intermittent. 5-HT was measured in the slice superfusates by HPLC with electrochemical detection. SP and NKA were measured by radioimmunoassay. The release of 5-HT was significantly enhanced using all stimulation paradigms and the evoked release of 5-HT per pulse was independent of the stimulation frequency. The release was found to be calcium dependent and there was no increase in the efflux of 5-hydroxyindoleacetic acid in response to stimulation. At 2 Hz (continuous), no significant increase in the release of SP was observed. Stimulation at higher frequencies yielded a significant increase in the release of SP per pulse. At 20 Hz, the release was increased by 73% (continuous) and 74% (intermittent), and at 50 Hz (intermittent) by 175% of basal efflux. The evoked release of NKA was also frequency dependent. At 2 Hz (continuous), no significant increase in the release of NKA was observed. At 20 Hz (intermittent), the evoked release per pulse was increased by 33% and at 50 Hz (intermittent) by 53% compared with the basal efflux of NKA. The results suggest that coexisting neurotransmitters/neuromodulators in the spinal cord may be released in different proportions depending on the stimulation frequency and that only 5-HT is released when the nerve terminal is activated by low-frequency stimulation.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract Neuron-enriched cultures derived from embryonic day 17 rat cerebral cortex were incubated in the presence of [3H]myristic or [3H]palmitic acid. Analysis of radiolabeled proteins by two-dimensional gel electrophoresis and fluorography revealed extensive incorporation of fatty acids into a small number of neuronal proteins. The major acylated proteins had apparent molecular weights and isoelectric points as follows: 87,000, 4.3; 63,000, 4.4; 45,000, 4.4; and 20,000, 5.3. After labeling with [3H]myristic acid, the radioactivity associated with these proteins was identified as myristic acid, which was attached via an ester linkage. All four of the major acylated neuronal proteins were found to be membrane-bound and enriched in growth cones. By virtue of its molecular weight, isoelectric point, subcellular distribution, and peptide map, the 87-kilodalton polypeptide was shown to be equivalent to pp80, a phosphoprotein that has been described in developing and mature synaptic terminals. The 45-kilo-dalton acylated protein also appears to coincide with another growth cone phosphoprotein, pp40. Acylation may serve as a mechanism to regulate the function of these proteins, or may play a role in directing them to the nerve terminal membrane.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 4273-4277 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    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 80 (1996), S. 3031-3042 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theoretical investigation of the electrical characteristics of GaN/AlxGa1−xN (x is the Al mole fraction in AlGaN) modulation doped field-effect transistors (MODFETs) is carried out. Using a self-consistent solution of Schrödinger's equation and Poisson's equation, relations between the concentration of two-dimensional electron gas (2DEG), the Fermi level in GaN, and the average distance of the electrons from the heterointerface are calculated. A relation between the gate bias and the 2DEG concentration is obtained for a flat quasi Fermi level in AlxGa1−xN. Based on the relation between the 2DEG concentration and the applied gate bias, a model for the drain current and the transconductance of the device is developed. The effects of the n-AlxGa1−xN layer thickness, the spacer i-AlxGa1−xN layer thickness, the n-AlxGa1−xN doping level, the aluminum mole fraction x, and the channel length L on the electrical characteristics of MODFETs are presented. Theoretical results are compared with the recent experimental data, which show striking agreement. The 2DEG concentration is found to be as high as 1013 cm−2, and transconductance as high as 1000 mS/mm. Finally, the effect of the difference in the properties of AlN and GaN, and a device structure that would take advantage of the bending of the quasi Fermi level for electrons in n-AlxGa1−xN, are discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 7498-7506 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A parametric study of single-crystal silicon roughness induced by an SF6 plasma has been carried out by means of atomic force microscopy. An helicon source (also called resonant inductive plasma etcher) has been used to study the relation between plasma parameters and subsequent surface damage. The surface damage has been examined in terms of height roughness analysis and in terms of spatial (lateral) extent of the surface roughness. The central result is that roughness scales with the ratio of the ion flux over the reactive neutral flux (J+/JF), showing the combined role of both ionic and neutral species. At low ion flux, the neutrals smooth the surface, while at higher ion flux, they propagate the ion-induced defects, allowing the roughness to be enhanced. Influences of other parameters such as exposure duration, ion energy, or substrate temperature have also been quantified. It is shown that the roughness growth is well described by an empirical law: rms∝(1/(square root of)E)(J+/JF)ηtβ, with η≈0.45 and β≈1 (rms is the root mean square of the roughness). In other respects, we analyze the data with a Fourier transform analysis. The main advantage is to minimize noise and to separate the magnitude of the roughness, the lateral correlation length on which the roughness is growing, and the behavior of short and long range roughness. The results are identical to the rms analysis, especially, the above scaling law. The time evolution of the lateral correlation length follows a scaling law (which is not accessible by means of the rms) leading to a fractal dimension of 2.67. Also is observed a variation of the short range roughness as a function of the substrate bias voltage. Consequence for further scaling down of integrated circuits is called to mind.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2509-2511 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have built a new injection-locking set-up which allows the study of low frequency noise in an oscillator. The interaction between a driving 100 MHz signal and a surface acoustic wave delay line oscillator undergoing a nonlinear modulational instability is investigated. Driving amplitude is used to control the synchronization range and therefore the frequency stability of a newly discovered carrier-envelope resonance process. In the soliton-locked regime, fundamental and subharmonic steps attached to a Lorentzian shape frequency-amplitude characteristic are found. They are explained thanks to a driven nonlinear Schrödinger model and the joined synchronization map. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    USA/Oxford, UK : Blackwell Science Ltd
    Cephalalgia 15 (1995), S. 0 
    ISSN: 1468-2982
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Despite the high prevalence of migraine in the population, the pathophysiology of this condition remains poorly understood. Vascular changes have been postulated. With positron emission tomography and various radiotracers, it is possible to have a non-invasive access to a number of parameters of interest in migraine research. These are presented and discussed in this article. PET has great potential for answering some basic questions concerning the physiological or biochemical changes that can occur during and between migraine attacks. Few studies have been published, however, probably because of (i) limitations inherent to the technique and (ii) problems in study design.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 94 (1987), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In six women with a normal vaginal delivery at term, in 12 women who had a suction curettage between 6 and 12 weeks gestation and in eight women with an ectopic pregnancy, the post-partum or the post-surgery decline in radioimmunoassayable SP1 was faster during the first 24 h after surgery or delivery than later, so that two half-lives were calculated. The first‘half-life’of about 20 h (0–24 h after delivery or surgery) was of the same order of magnitude in all groups studied and corresponded well to previously published values. The mean second‘half-life’(〈24 h after delivery or surgery) was significantly longer in term (72·2 h) and in ectopic pregnancies (64·1 h) than in first trimester pregnancies (45·5 h). These results might indicate that the metabolism of SP1 either changes during pregnancy or that the changing SPlβ/SPlα ratio during pregnancy markedly influences the levels of SP1 as measured by radioimmunoassay.
    Type of Medium: Electronic Resource
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