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  • 11
    Electronic Resource
    Electronic Resource
    STUDIES ON THE REGULATION OF GABA SYNTHESIS: SUBSTRATE-PROMOTED DISSOCIATION OF PYRIDOXAL-5′-PHOSPHATE FROM GAD (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 30 (1978), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The association between glutamate decarboxylase (GAD) and its cofactor, pyridoxal-5′-phos-phate (pyridoxal-P), was studied using 20,0000 supernatant of rat brain. In this preparation GAD required added pyridoxal-P to maintain a linear reaction rate beyond 5 min of incubation. Following exhaustive dialysis the enzyme was more than 83% saturated with cofactor indicating that the cofactor was tightly bound to the enzyme. When incubations were performed in the presence of glutamate and without added pyridoxal-P there was a progressive inactivation of the enzyme which was dependent on the glutamate concentration. This lost activity was almost completely recovered by addition of pyridoxal-P to the dialyzed glutamate-inactivated enzyme. The results suggest that glutamate inactivates GAD by promoting the dissociation of pyridoxal-P from the enzyme thereby producing inactive apoen-zyme which can be reactivated by combining with available pyridoxal-P. This interpretation is supported by the finding that progress curves for the reaction were accurately described over a 30 min incubation period and 10-fold glutamate concentration range by an integrated rate equation which takes the glutamate-promoted dissociation of cofactor into account. The progressive inactivation could not be attributed to denaturation of the enzyme, impurities in the substrate, effects of pH, depletion of substrate, protein concentration, sulfhydryl reagents or product inhibition. The results presented here also show that certain precautions must be adopted to accurately measure GAD activity in the absence of added pyridoxal-P as has been widely done in studies of drug action. Specifically, measurements must be made at short times of incubation and low concentrations of glutamate to minimize the glutamate-promoted inactivation of the enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1978.tb06538.x
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  • 12
    Electronic Resource
    Electronic Resource
    STUDIES ON THE REGULATION OF GABA SYNTHESIS: THE INTERACTION OF ADENINE NUCLEOTIDES AND GLUTAMATE WITH BRAIN GLUTAMATE DECARBOXYLASE (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 30 (1978), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effects of adenine nucleotides and glutamate on glutamate decarboxylase were studied in a dialyzed, high-speed supernatant of rat brain. When incubated with 10 μm-pyridoxal-P the enzyme was strongly inhibited by ATP, ADP and their Mg2+ complexes at concentrations which were well below tissue levels. The enzyme was not significantly inhibited by 15 mm-AMP or by 100 μM-3′-5’cyclic AMP or 3′-5’cyclic GMP. Inhibition by the nucleotides cannot be described in conventional steady-state kinetic terms. Addition of ATP in the presence of pyridoxal-P resulted in a slow, progressive decrease in the reaction rate which was similar to the inactivation observed when the enzyme was incubated in the absence of pyridoxal-P. The progressive inactivation in the presence of ATP was minimal at concentrations of glutamate which were well below Km and became much more pronounced at higher glutamate concentrations. Addition of suprasaturating amounts of pyridoxal-P late in the incubation when the enzyme was almost completely inactivated resulted in an immediate and complete reactivation of the enzyme. Inhibition by ATP could be prevented by addition of saturating amounts of pyridoxal-P at the start of the reaction and was also relieved by addition of potassium phosphate buffer. The results suggest that inhibition by the nucleotides involves the prior formation of the inactive apoenzyme which results from the glutamate-promoted dissociation of pyridoxal-P. In the absence of the nucleotides, the enzyme is normally reactivated by the added pyridoxal-P. The nucleotides act to block this reassociation of pyridoxal-P with the apoenzyme thereby producing a progressive inactivation of the enzyme. The implications of these results for the regulation of GABA synthesis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1978.tb06539.x
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  • 13
    Electronic Resource
    Electronic Resource
    THE MANAGEMENT OF SOCIAL EXPERIMENTS: A COMMENT ON THE PAPER BY IRA S. LOWRY (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Papers in regional science 37 (1976), S. 0 
    Details
    ISSN: 1435-5957
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1435-5597.1976.tb00969.x
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  • 14
    Electronic Resource
    Electronic Resource
    Technology transfer and the process of technological innovation: new concepts, new models (1976)
    Oxford, UK : Blackwell Publishing Ltd
    R & D management 6 (1976), S. 0 
    Details
    ISSN: 1467-9310
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: Many so-called ‘technology transfer’ programs are based on the belief that the process is essentially one of communication rather than of innovation. As such, the designers and managers of such programs concern themselves with questions of how to transfer technology after it is already developed, rather than how to develop or adapt technology so that it is transferable. The net result, we believe, has been a very poor showing and a very low level of effectiveness. To design a successful transfer program one must develop a view of the flow of technology in an integrated innovation process, and this paper concludes with the presentation of a highly significant flow model in which the critical aspect is constant assessment of the non-technological factors during the entire course of the innovation cycle–including those related to marketing, regulations, capital and human resources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1467-9310.1976.tb01248.x
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  • 15
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    PIANO LAB AT M.I.T. (1975)
    New York : Periodicals Archive Online (PAO)
    Music journal. 33:7 (1975:Sept.) 12 
    Details
    ISSN: 0027-4364
    Topics: Musicology
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:1166-1975-033-07-000003
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  • 16
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    Historical References in Chekhov's Later Stories (1976)
    Cambridge : Periodicals Archive Online (PAO)
    The Modern language review. 71:3 (1976:June) 595 
    Details
    ISSN: 0026-7937
    Topics: Linguistics and Literary Studies
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:0094-1976-071-03-000010
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  • 17
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    A Note on the Relationship between Higher Education and Political Trust (1977)
    Washington, D.C., etc. : Periodicals Archive Online (PAO)
    Teaching political science. 4:4 (1977:July) 435 
    Details
    ISSN: 0092-2013
    Topics: Political Science
    Notes: Teaching Notes
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:f721-1977-004-04-000006
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  • 18
    Electronic Resource
    Electronic Resource
    Source of the solar flare energy (1976)
    Springer
    Solar physics 47 (1976), S. 183-192 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent Skylab and magnetograph observations indicate that strong photospheric electric currents underlie small flare events such as X-ray loops and surges. What is not yet certain, because of the non-local dynamics of a fluid with embedded magnetic field, is whether flare emission derives from the energy of on-site electric currents or from energy which is propagated to the flare site through an intermediary, such as a stream of fast electrons or a group of waves. Nevertheless, occurrences of: (1) strong photospheric electric currents beneath small flares; (2) similar magnetic fine structure inside and outside active regions; (3) eruptive prominences and coronal white light transients in association with big flares; and, (4) active boundaries of large unipolar regions suggest the possibility that all phenomena of solar activity are manifestations of the rapid ejection and/or gradual removal of electric currents of various sizes from the photosphere. The challenge is to trace the precise magnetofluid dynamics of each active phenomenon, particularly the role of electric current build-up and dissipation in the low corona.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152255
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  • 19
    Electronic Resource
    Electronic Resource
    Tabulation of the harmonic coefficients of the solar magnetic fields (1975)
    Springer
    Solar physics 41 (1975), S. 225-226 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Tables of spherical harmonic coefficients for the global photospheric magnetic field between 1959 and 1974 are now available on microfilm. (These are the same coefficients which were used to construct the maps of the coronal magnetic atlas.)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152968
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  • 20
    Electronic Resource
    Electronic Resource
    High resolution mapping of the magnetic field of the solar corona (1977)
    Springer
    Solar physics 51 (1977), S. 345-375 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High resolution KPNO magnetograph measurements of the line-of-sight component of the photospheric magnetic field over the entire dynamic range from 0 to 4000 gauss are used as the basic data for a new analysis of the photospheric and coronal magnetic field distributions. The daily magnetograph measurements collected over a solar rotation are averaged onto a 180 × 360 synoptic grid of equal-area elements. With the assumption that there are no electric currents above the photospheric level of measurement, a unique solution is determined for the global solar magnetic field. Because the solution is in terms of an expansion in spherical harmonics to principal index n = 90, the global photospheric magnetic energy distribution can be analyzed in terms of contributions of different scale-size and geometric pattern. This latter procedure is of value (1) in guiding solar dynamo theories, (2) in monitoring the persistence of the photospheric field pattern and its components, (3) in comparing synoptic magnetic data of different observatories, and (4) in estimating data quality. Different types of maps for the coronal magnetic field are constructed (1) to show the strong field at different resolutions, (2) to trace the field lines which open into interplanetary space and to locate their photospheric origins, and (3) to map in detail coronal regions above (specified) limited photospheric areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216372
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