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  • 1
    Electronic Resource
    Electronic Resource
    Uptake and reduction of glycerate by isolated chloroplasts (1974)
    Springer
    Planta 120 (1974), S. 31-46 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00388269
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  • 2
    Electronic Resource
    Electronic Resource
    Amino acid permeability of the chloroplast envelope as measured by light scattering, volumetry and amino acid uptake (1974)
    Springer
    Planta 120 (1974), S. 47-61 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00388270
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  • 3
    Electronic Resource
    Electronic Resource
    Output power saturation in high current regions of different noble-gas ion lasers (1974)
    Springer
    Applied physics 5 (1974), S. 203-210 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00928130
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  • 4
    Electronic Resource
    Electronic Resource
    Gegenseitige Beeinflussung der beiden Ar+-Laserlinien 4880 und 5145 Å (1973)
    Springer
    The European physical journal 259 (1973), S. 355-364 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01395941
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  • 5
    Electronic Resource
    Electronic Resource
    Investigation of photon-photon angular correlations in atomic mercury (1970)
    Springer
    The European physical journal 240 (1970), S. 71-92 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01400170
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  • 6
    Electronic Resource
    Electronic Resource
    Resonanzabsorption in Medien kleiner optischer Dichte (1973)
    Springer
    The European physical journal 261 (1973), S. 423-430 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01395699
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  • 7
    Electronic Resource
    Electronic Resource
    Sättigungsverhalten und Verlauf der Elektronentemperatur beim Argon-Ionenlaser (1971)
    Springer
    The European physical journal 241 (1971), S. 280-290 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01395335
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  • 8
    Electronic Resource
    Electronic Resource
    Static electric quadrupole interaction of Ta- and Hf-ions in barium and lead titanate (1972)
    Springer
    The European physical journal 257 (1972), S. 336-352 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The static electric quadrupole interaction of181Ta and178Hf in polycrystalline barium and lead titanate at the site of titanium has been measured using time differential PAC and the Mössbauer effect. The electric field gradients (EFG) at room temperature at the181Ta nucleus are ¦V zz¦=(3.6±0.2)·1017V/cm2 in BaTiO3 and ¦V zz¦=(14.6±0.6)·1017 V/cm2 in PbTiO3. The temperature dependence of the quadrupole interaction has been studied giving the following EFG values: ¦V zz¦=(2.4±0.2)·1017 V/cm2 in the monoclinic and ¦V zz¦=(1.1±0.3)·1017 V/cm2 in the rhomboedral phase of BaTiO3, and ¦V zz¦=(15.7±0.6)·1017 V/cm2 for181Ta/PbTiO 3 at 77 °K. The EFG of178Hf in PbTiO3 has been derived from a Mössbauer effect experiment to beV zz=+(10.7±0.5)·1017 V/cm2. The results are compared with EFG's calculated in a point charge model and with experimental EFG's measured at44Sc and57Fe in the same titanates by other authors. Contributions of covalent bonds to the effective EFG's in perovskit crystals are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01392991
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  • 9
    Electronic Resource
    Electronic Resource
    The electric fieldgradient at Cd-impurities in heavy rare earth metals (1973)
    Springer
    The European physical journal 265 (1973), S. 197-206 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The static electric quadrupole interaction of111Cd in the heavy rare metals Gd, Tb, Ho and Er has been studied at room temperature by time differential perturbed angular correlation techniques. From these measurements the effective electric field-gradient,V zz eff , at the Cd-site was derived on a relative scale. The lattice contributions,V zz lat , to the total electric fieldgradient have been determined by lattice-sum calculations. The ratioα=V zz eff /V zz lat , which to a certain extent represents the conduction electron contribution to the electric fieldgradient, decreases with increasing atomic number. Possible reasons for this behaviour are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01394657
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  • 10
    Electronic Resource
    Electronic Resource
    Static electric quadrupole interaction of Ce and Pb ions in lead titanate (1974)
    Springer
    The European physical journal 269 (1974), S. 265-267 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The static electric quadrupole interaction of140Ce and204Pb has been studied in polycrystalline PbTiO3 at the lead site with the time-differential perturbed angular correlation (TDPAC) method. The interaction frequencies areω Q(2083 keV;140Ce)=2.11 (17) MHz andω Q(1274keV;204Pb)=3.60(3) MHz. The results are compared with the electric field gradient calculated in a point charge model. Under the assumption that the covalent contributions for Ce and Pb are equal, one can derive the quadrupole moment of the 1274 keV state of204Pb to be ¦Q¦=0.68 b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01668692
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