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  • 1970-1974  (11)
  • 1965-1969  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Planta 120 (1974), S. 31-46 
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intact chloroplasts of spinach (Spinacia oleracea L.) evolve O2 in the light in a glycerate-dependent reaction at rates usually close to 10 μmolxmg-1 chlorophyllxh-1. Glycerate isfirst phosphorylated and the resulting phosphoglycerate reduced to the sugar level. Products of the reaction are the intermediates of the Calvin cycle and glycolate. The ratio of triosephosphates to phosphoglycerate is higher under low light or at a low pH than under high light or at a high pH. Chloroplasts contain activities of glycerate kinase which approximately correspond to observed glycerate reduction rates at light saturation. The main part of the glycerate kinase of leaf cells is localized in the chloroplasts, but considerable activity also resides outside these organelles. Glycerate can enter intact chloroplasts of spinach as the anion and the undissociated acid. It can thus mediate indirect proton transfer across the chloroplast envelope. In the presence of slowly permeating cations it is taken up mainly in an anion exchange reaction. Chloride and acetate anions permeate faster than the glycerate anion. The relation between glycerate reduction and photorespiration is discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The amino acid permeability of the envelope of intact, functional spinach (Spinacia oleracea L.) chloroplasts was investigated by light scattering, volumetry and uptake of 14C-labelled amino acids. The criterion for the functionally of the chloroplasts was their ability to reduce CO2, PGA and oxaloacetate in the light at high rates. Net uptake into the chloroplast interior of neutral amino acids such as alanine, glycine, serine, proline, threonine or valine occurred only at very low rates. The uptake was concentration dependent, indicating unspecific diffusion rather than carrier-mediated transport. The slowness of uptake is emphasized by the capability of neutral amino acids to provide osmotic support for intact chloroplasts during a considerable length of time. Back-exchange experiments also failed to indicate the existence of specific exchange carriers for the transport of neutral amino acids such as alanine or glycine through the envelope of intact chloroplasts. Dicarboxylic amino-acids are known to be taken up by the so-called dicarboxylate translocator. The same carrier was found to catalyze also the transfer of asparagine and glutamine. The data do not support current assumptions concerning fast carrier-mediated transport of neutral amino acids and their role in the transfer of carbon during photosynthesis.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Investigations of “antibody-suppressible” and “non-suppressible” ILA have been performed in two groups of women during an oral glucose tolerance test (100 g Glucose per os). Group 1: Women 3–6 days after the delivery of a baby with normal weight (about 3300 g); group 2: Women 3–6 days after the delivery of a big baby (weight about 4300 g). Inspite of a normal glucose tolerance in all subjects it could be demonstrated that the women of group 2 showed a delayed and significantly higher increase of the fat pad ILA and the “suppressible” ILA, particularly. This behaviour of the insulin secretion seems to be a prediabetic symptom.
    Notes: Zusammenfassung Bei Wöchnerinnen wurden vor und nach oraler Belastung mit 100 g Glucose Bestimmungen der Seruminsulinspiegel durchgeführt. Dabei zeigte sich, daß Frauen, die von Kindern mit einem durchschnittlichen Geburtsgewicht von 4300 g entbunden worden waren, mit einem verzögerten und signifikant höheren Anstieg der Werte des „freien“ (mit Antiserum unterdrückbaren) Insulins und der gesamten „insulinähnlichen Aktivität“ reagierten als Mütter von normalgewichtigen Kindern (Durchschnittsgewicht 3300g). Da die Glucosetoleranz bei allen Probandinnen normal war, kann dieser Befund neben dem erhöhten Geburtsgewicht als prädiabetisches Symptom angesehen werden.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary “Suppressible” and “non-suppressible” insulin was estimated in 25 glycosuric pregnant women with a normal glucose tolerance. After application of 100 g glucose orally 11 pregnants with a history of a “large baby” or a family history of diabetes showed a delayed but significantly higher increase of suppressible insulin (and whole ILA) than the other 16 pregnants. This behaviour of the insulin secretion seems to be a prediabetic symptom.
    Notes: Zusammenfassung Bei 25 glucosurischen Schwangeren mit normaler Glucosetoleranz wurden die Serumspiegel des „freien“ (mit Antiserum unterdrückbaren) und des „gebundenen“ (nicht unterdrückbaren) Insulins nach Belastung mit 100 g Glucose per os untersucht. Dabei zeigte sich, daß 11 Frauen mit familiärer Diabetesbelastung oder mit Geburten übergewichtiger Kinder in der Anamnese einen trägen, verzögerten Anstieg der signifikant erhöhten Spiegel des „freien“ (und Gesamt-) Insulins aufweisen im Vergleich zu den übrigen 16 Schwangeren des Kollektivs. Dieses Verhalten der Insulinsekretion ist als ein prädiabetisches Symptom anzusehen.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Is oxidative phosphorylation the only mechanism controlling the respiratory activity of mitochondria ? In isolated rat heart mitochondria the sites of metabolic control seem to vary with the respiratory ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 5 (1974), S. 203-210 
    ISSN: 1432-0630
    Keywords: Saturation of ion lasers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Detailed experiments with cw noble gas ion lasers in high current regions are reported. Optimum lasing conditions and saturation behaviour of individual laser transitions in singly and doubly ionized argon, krypton, and xenon have been investigated. Various saturation mechanisms are discussed, such as resonance-radiation trapping, collisional deexcitation, multiple ionization, radial and axial gas pumping, and optical degradation of the cavity mirrors. The experimental results indicate that resonanceradiation trapping is the most probable cause of power limitation in noble-gas ion lasers.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 259 (1973), S. 355-364 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Ar+-laser-transition 4880 Å shows a decrease of the output power caused by the simultaneous laser action of the transition 5145 Å. Both lines correspond to the same lower level. The mutual influence of these transitions was calculated by solving the rate equations for the density of the excited ions. The calculations were compared with experiments.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 240 (1970), S. 71-92 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract By application of the time differential coincidence technique developed in nuclear spectroscopy, for the first time the angular correlation of light quanta of atomic decays was observed. The experiments were carried out with the 73 S 1-63 P 1-61 S o-cascade of mercury excited by electron impact at energies of 50 eV. The two transitions of 4358 and 2536 Å were selected by interference filters and detected by photomultipliers. Time differential coincidence spectra were measured at the two angular positions 0=90 ° and 0=180 °. It was found that the excitation of the 73 S 1-state by the electron beam leads to no alignment. Therefore the usual γ-γ angular correlation theory is applicable. Perturbations occur by static interaction with external magnetic fields and by free hyperfine interaction in the odd isotopes of mercury. The interaction frequencies of the free hyperfine interaction are in all cases too high to be resolved. Measurements were performed using mercury of natural abundances, with and without external magnetic fields. First of all the spin rotation in the magnetic field of the earth (690 mG) was observed, giving for theg-factor of the 63 P 1-state $$g(Hg, 6^3 P_1 ) = 1.35 \pm 0.10.$$ This value is in agreement with the more precise values determined by other techniques. Shielding of the earth's field gave a nearly unattenuated angular correlation, with an integral attenuation factor of $$G_2 = 0.98 \pm 0.06.$$ The value of the angular correlation coefficientA 2. $$A_2 = - 0.188 \pm 0.009,$$ is in good agreement with the expected average value for the natural isotope mixture $$\overline {A_2^{theor} } = - 0.196.$$ A third measurement in an external magnetic field of 5.6 G showed several complete spin rotations. A nice fit was possible by using the superposition of all six participating cascades in the hyperfine level schemes of the different isotopes. The theoretical anisotropies,g F -values, and intensities were inserted according to natural isotope abundances. From the time differential measurements also a value for the lifetime of the Hg-63 P 1-level was derived. The result $$\tau (Hg, 6^3 P_1 ) = (120 \pm 2) nsec$$ is in agreement with earlier measurements. Further applications of the method are discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 261 (1973), S. 423-430 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The calculations of the inversion population of gas lasers must take into account, that the lifetime of laser levels can differ from those of isolated atoms. This can be caused by resonance absorption if one of the laser levels is a resonant level. As the theory of Holstein is not applicable for small specular transmission density, an escape factor has been calculated in this case.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 241 (1971), S. 280-290 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recently saturation of laser power ofCW ion lasers has been observed with large bored laser tubes made of metal segments. The saturation was observed in Argon, Krypton and Xenon in high current regions. In this case it was necessary to calculate the correlation between the electron temperature, electron- and ion-density and on the other hand the discharge quantities as current density and voltage drop. By measuring the discharge quantities at optimum laser power it is possible to determine the optimum electron temperature for any current density. The comparison of the run of these quantities leads to the assumption that the saturation mechanism causes a decrease of the optimum electron temperature.
    Type of Medium: Electronic Resource
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