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  • 11
    Electronic Resource
    Electronic Resource
    Resonant Raman scattering in germanium
    Amsterdam : Elsevier
    Solid State Communications 10 (1972), S. 591-595 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(72)90598-4
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  • 12
    Electronic Resource
    Electronic Resource
    Magneto-reflectance of the 1S exciton ground states in InP and GaAs
    Amsterdam : Elsevier
    Solid State Communications 14 (1974), S. 783-786 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(74)90885-0
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  • 13
    Electronic Resource
    Electronic Resource
    Heme-apoprotein interaction in the modified oxyhemoglobin-bis(N-maleimidomethyl)ether andin oxyhemoglobin at high Cl^- concentrations detected by resonance Raman scattering
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular 830 (1985), S. 224-232 
    Details
    ISSN: 0167-4838
    Keywords: Chemical modification ; Cl^- effect ; Heme-apoprotein interaction ; Oxyhemoglobin structure ; Resonance Raman scattering
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-4838(85)90278-X
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  • 14
    Electronic Resource
    Electronic Resource
    Correlation of pH-dependent resonance Raman and optical absorption data reflecting haem-apopprotein interaction in oxy haemoglobin
    Amsterdam : Elsevier
    Journal of Molecular Structure 143 (1986), S. 457-460 
    Details
    ISSN: 0022-2860
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-2860(86)85299-1
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  • 15
    Electronic Resource
    Electronic Resource
    The analyzation of the depolarization ratio-dispersion of resonant Raman lines in haemproteins. A suitable tool to detect haem-protein interaction.
    Amsterdam : Elsevier
    Journal of Molecular Structure 143 (1986), S. 453-456 
    Details
    ISSN: 0022-2860
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-2860(86)85298-X
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  • 16
    Electronic Resource
    Electronic Resource
    A model of early evolution of karst conduits affected by subterranean CO2 sources (2000)
    Springer
    Environmental geology 39 (2000), S. 531-543 
    Details
    ISSN: 1432-0495
    Keywords: Key words Karst ; Speleogenesis ; Subterranean ; CO2 ; Limestone dissolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  In investigating early karstification of one-dimensional conduits by computer models, so far one has assumed that the CO2 content of the calcite aggressive water stems entirely from the surface. Subterranean sources of CO2, however, can rejuvenate the solutional power of water already close to equilibrium with respect to calcite, and boost dissolution rates. In a first scenario we have investigated the influence of a punctual source of CO2 as the most simple case of release of CO2 into a karstifiable fracture at some position KL from its entrance of the widening joint with length L, (K〈1). The results show that only a small increase of the p CO2 in the solution to about 0.01 atm is sufficient to reduce the breakthrough times to about 0.3 with respect to the case, where no CO2 is delivered. Other sources of CO2 are due to the metabolic activity of microorganisms. The existence of such diverse subterraneous microbial life in karst systems is demonstrated. Whether situated on the fissure surfaces or free floating in the karst water, one basic product of their metabolism is CO2. This contributes over the whole flow path to the p CO2 of the karst water. Therefore in a second scenario we assumed a constant rate of CO2-input along parts of the fracture, as could be delivered by the activity of aerobic bacteria dwelling at its walls. Such a scenario also applies to an extended diffuse CO2 migration from volcanic activity deep underground. In this case drastic reductions of the breakthrough time by about one order of magnitude are observed. These reductions are enhanced when the fracture aperture width of the initial fracture decreases. The physicochemical mechanisms of enhancement of karstification are discussed in detail by considering the evolution of the fracture aperture width and of the dissolution rates in space and time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050464
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  • 17
    Electronic Resource
    Electronic Resource
    Investigation of pH-induced symmetry distortions of the prosthetic group in deoxyhaemoglobin by resonance Raman scattering (1983)
    Springer
    European biophysics journal 10 (1983), S. 241-256 
    Details
    ISSN: 1432-1017
    Keywords: Deoxyhaemoglobin ; Resonance Raman scattering ; Dispersion of depolarization ratio ; Symmetry distortions ; Bohr effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The depolarization ratio and the excitation profiles of the Raman line at 1,355 cm−1 (oxidation marker) of deoxyhaemoglobin show a significant dispersion in the region between the α- and Soret-band, which is drastically dependent on the pH-value of the solution. The experimental data are interpreted by extending the Loudon theory of the Raman tensor by introducing static distortions of the haem group, which result from haem-apoprotein interactions. Thus, a Raman tensor results as a linear combination of A 1g , A 2g , B 1g , B 2g Raman tensors in D 4h -symmetry. By fitting the data to this expression, constants are obtained which are related linearly to symmetry classified distortions of the haem group. The variation of all these distortions shows a similar pH-dependence, which is interpreted to be caused by protonation processes of two titrable groups with pK1=4.3 and pK2=5.4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535552
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  • 18
    Electronic Resource
    Electronic Resource
    The influence of structural variations in the F- and FG-helix of the β-subunit modified oxyHb-NES on the heme structure detected by resonance Raman spectroscopy (1989)
    Springer
    European biophysics journal 17 (1989), S. 87-100 
    Details
    ISSN: 1432-1017
    Keywords: Oxyhemoglobin-NES ; resonance Raman scattering ; depolarization ratio ; tertiary effector binding ; Bohr effect ; heme-apoprotein interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The dispersion of the depolarization ratio of two prominent Raman lines (1,375 cm−1 and 1,638 cm−1) of oxyhemoglobin-N-ethyl succinimide have been examined for pH values between pH=6.0 and 8.5. Both exhibit a significant pH dependence. Calculation of the Raman tensor in terms of a fifth-order time dependent theory provides information about the pH-dependence of parameters reflecting symmetry classified distortions of the prosthetic heme group. To correlate these distortions with the functional properties of the molecule the following protocol was used: 1) An allosteric model suggested by Herzfeld and Stanley (1974) has been applied to O2-binding curves measured at different pH values between 6.5 and 9.0. From this calculation one obtains both, the energy differences between different molecular conformations and the equilibrium constants of oxygen and proton binding. 2) A titration model was formulated relating each conformation of a molecule to a distinct set of distortion parameters of the heme group. 3) The distortion parameters resulting from the analysis of our Raman data were assigned as an effective value due to incoherent superposition of the distortion parameters related to the different titration states. The application of this procedure yields an excellent reproduction of the pH-dependent effective distortion parameters of both Raman lines investigated. It is shown that the protonation of two tertiary effector groups located in the β-subunits affect the symmetry of the heme in a contrary manner: the protonation of a His-residue (pK=8.2, probably His(FG4)β) causes a symmetric position of the proximal imidazole thus lowering the perturbations of the heme core. Further it influences the interaction between amino acid residues of the heme cavity and pyrrole side chains (probably Val (FG5)β-vinyl (pyrrole 3) thus causing a decrease of the distortions related to the peripheral part of the heme. In contrast, the protonation of Lys (EF6) β causes a tilt position of the proximal imidazole and an increase of asymmetric perturbations of the heme core, whereas the interaction between the pyrrole side chains and the heme cavity is weakened. Our results are consistent with stereochemical predictions of Moffat (1971) concerning the existence of an H-bond between His(FG4)β and Cys(F9)β.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257106
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  • 19
    Electronic Resource
    Electronic Resource
    Investigation of pH-induced symmetry distortions of the prosthetic group in oxyhaemoglobin by resonance Raman scattering (1984)
    Springer
    European biophysics journal 11 (1984), S. 61-76 
    Details
    ISSN: 1432-1017
    Keywords: Oxyhaemoglobin ; resonance Raman scattering ; dispersion of depolarisation ratio ; fifth-order Raman theory ; alkaline Bohr effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The depolarisation ratio and the excitation profiles of some prominent Raman lines of the oxyhaemoglobin spectrum (1,375 cm-1, 1,583 cm-1, 1,638 cm-1) have been measured as functions of the exciting laser frequency. The depolarisation ratio shows a complicated minimum-maximum structure in the preresonant region between Soret- and β-band of the optical spectrum, which depends on the pH-value of the solution. These dispersion curves are interpreted by fifth-order Loudon theory of the polarisability tensor including static distortions of the haem group, which lower its symmetry from the ideal D 4h-symmetry, and enhancement by a second, non-Raman-active phonon. The fitting constants needed to fit the experimental data are related to static distortions of A 1g, B 1g, B 2g, and A 2g` symmetry types and thus give information on the symmetry lowering from D 4h. The variation of the fitting constants with the pH-value of the solution is interpreted to be caused by protonation/deprotonation processes of titrable amino acid groups contributing to the alkaline and acid Bohr effect. The protonation changes the electrostatic interaction energies in the globular protein and destabilises the salt bridge between His(HC3)β and Asp(FG1)β in the R-state. These processes induce distortions of the haem group via haem-apoprotein interactions. Our results give no indication for a dominant role of the covalent Fe2+-N[His(F8)] bond in this process. They are in agreement, however, with the allosteric model of Hopfield, which assumes all interactions to be evenly distributed all over the protein molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00253859
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  • 20
    Electronic Resource
    Electronic Resource
    Determination of the Raman tensor of the haem group in myoglobin by resonance Raman scattering in solution and single crystals (1983)
    Springer
    European biophysics journal 10 (1983), S. 257-273 
    Details
    ISSN: 1432-1017
    Keywords: Myoglobin ; Resonance Raman scattering ; Dispersion of depolarization ratio ; Symmetry distortions ; Haem ; Single crystals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We have measured the depolarization ratio and the excitation profiles of the Raman lines at 1,355 cm−1, 1,564 cm−1 and at 1,373 cm−1, 1,580 cm−1 in solutions of deoxy Mb and ferric MbCN, respectively, in the region between the Soret and the α, Β-bands. From their dispersion we have determined the tensor components of the Raman tensor by an extension of Loudon's theory, taking into account static distortions from the ideal D 4h -symmetry of the haem group, induced by haem-protein interactions and the interaction of the side-chains with the porphyrin skeleton (Schweitzer et al. 1984). Analogous to the excitation profiles in solution, measurements on Mb single crystals yield intensities I a, b which are related to the tensor components viewed in the laboratory system, spanned by the three orthogonal crystals axes a, b, c *. By using the structural data of the crystals and coordinate transformation from the system of the molecular coordinates into the laboratory system, the quantities I a, b can be calculated by use of the tensor components determined from the solution data. The values thus calculated and those which are determined experimentally from the single crystals are in good agreement. This confirms the theoretical approach of Schweitzer et al. (l984).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535553
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