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  • 11
    Electronic Resource
    Electronic Resource
    Depolymerization of hyaluronate by the phototoxic drugs phenothiazines and sulfacetamide (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 84-89 
    Details
    ISSN: 1435-1536
    Keywords: Key words Hyaluronate ; Depolymerization ; Phenothiazines ; Sulfacetamide ; UV irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Phenothiazines (promazine, promethazine, chlorpromazine) and sulfacetamide, known as phototoxic drugs, depolymerize aqueous sodium hyaluronate (HA) on exposure to light. The reduction in the HA molecular weight was followed by size-exclusion chromatography with low-angle laser light scattering. In the low-concentration region of the drugs below 0.05 mM, the rate constants of depolymerization increased. The molecular weight of HA was practically unchanged without UV irradiation in the presence of drugs or with UV irradiation in the absence of drugs, indicating the phenothiazines and sulfacetamide require photoenergy to yield any kind of damaging chemical species for HA depolymerization. An involvement of active oxygen radicals in the effects of promazine and promethazine was evidenced by inhibition under anaerobic conditions. Further, addition of mannitol controlled the reaction in the presence of oxygen, pointing to hydroxyl radicals as the damaging agent. Chlorpromazine and sulfacetamide preferably depolymerized HA under anaerobic conditions, suggesting the participation of hydrated electrons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050014
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  • 12
    Electronic Resource
    Electronic Resource
    Quantum Tunneling of D(H) Atoms and 2 – in Solid Hydrogen (1998)
    Springer
    Journal of low temperature physics 111 (1998), S. 453-461 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper contains three results. First, the rate constants for the tunneling reaction HD + D → H + D 2 in solid HD increase steeply with increasing temperature above 5 K, while they are almost independent of temperature below 5 K. A mechanism of a vacancy–assisted tunneling reaction is proposed to account for this temperature dependence. Second, a hydrogen atom and a hydrogen molecule form a van der Waals complex in the Ar matrix at 20 K, where the tunneling reaction HD + D →H + D 2 takes place in this complex. The analysis of well–resolved ESR spectra of the complex determined the distance between a hydrogen atom and a hydrogen molecule as 2.3 – 2.5 Å. Third, the decay rate constants of $${\text{H}}_{\text{2}}^ - $$ anions in solid parahydrogen decrease with decreasing temperature below 6.6 K, attain the minimum value at 5 K, and then increase with decreasing temperature in the range of 5 → 2.7 K. The abnormal temperature dependence of the decay rate constants below 5 K is ascribed to a phonon–scattering process of quantum diffusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022264509705
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  • 13
    Electronic Resource
    Electronic Resource
    Landau laminar intermediate state structures with straight Normal-Superconducting boundaries (1988)
    Springer
    Journal of low temperature physics 71 (1988), S. 215-221 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Under the criterion that normal-superconducting (NS) boundaries are straight when the sample thickness is less than the coherence length, experimental conditions for superconducting lead and aluminum are investigated where Landau laminar intermediate state structures with straight NS boundaries are expected. It is shown that in a narrow range near the critical temperature and in low magnetic fields, type I superconductors thicker than the critical thickness should have a laminar structure with straight NS boundaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00118576
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  • 14
    Electronic Resource
    Electronic Resource
    Landau intermediate state structure in type I superconductors (1984)
    Springer
    Journal of low temperature physics 54 (1984), S. 63-80 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Landau laminar structures are discussed for cases where the normal-superconducting (N-S) boundary is curved and where it is straight throughout a sample. A numerical calculation shows that the free energy for a curved N-S boundary is less than that for a straight one, except for values ofd/Δ less than about 8 and a small region of magnetic fields close toh ⊥. Here Δ is the surface energy parameter andh ⊥ is the perpendicular critical field corresponding to a sample thicknessd. The expression forh ⊥ for the straight N-S boundary is different from that obtained by Simonin and López. It is shown that the data ofh ⊥ reported to date are insufficient to verify the formation of laminar structures with a straight N-S boundary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00681477
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  • 15
    Electronic Resource
    Electronic Resource
    Experimental Observation of 2 – Anion and its para → ortho Conversion in Solid para hydrogen Using High–Resolution ESR Spectroscopy (1998)
    Springer
    Journal of low temperature physics 111 (1998), S. 509-514 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present experimental observations and study of $${\text{H}}_{\text{2}}^ - $$ in solid parahydrogen. Since the parahydrogen molecule does not produce local magnetic fields, high–resolution ESR spectra of trapped radicals can be observed in the solid parahydrogen matrices. Using this high–resolution ESR spectroscopy, new quartet ESR signals were observed in γ–rays irradiated solid parahydrogen and assigned as $${\text{H}}_{\text{2}}^ - $$ In addition, para– $${\text{H}}_{\text{2}}^ - $$ was observed to convert into ortho– $${\text{H}}_{\text{2}}^ - $$ on the storage at 4.2 K. On the other hand, ortho–H 2 molecule converts into para– $${\text{H}}_{\text{2}}^ - $$ at cryogenic temperatures. The difference in the conversion between the H 2 molecule and the $${\text{H}}_{\text{2}}^ - $$ anion is explained by the parity conservation law of wavefunctions on exchanging the protons in homonuclear diatomic molecules such as the $${\text{H}}_{\text{2}}^ - $$ anion and H 2 molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022280913340
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  • 16
    Electronic Resource
    Electronic Resource
    Decay of 2 - Anions in Solid Parahydrogen via Two-Stage Quantum Tunneling Diffusion Processes (1999)
    Springer
    Journal of low temperature physics 114 (1999), S. 413-429 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Decay mechanism of H 2 - anions in X(γ)-irradiated solid para-H2 (p-H 2 ) has been studied using high-resolution ESR spectroscopy in the temperature range between 1.3–6.6 K. The results are summarized as follows. First,the decay rate constant of the 2 - anions is not proportional to initial yields of reactive species such as cations and H atoms but proportional to the concentration of less-reactive species of HD molecules in p-H2 . This result shows that the decay of the 2 - anion is due to the reaction neither with cations nor H atoms but with HD molecules originally contained in the p-H2 sample at natural abundance. Second,the decay rate constant of the 2 - anions increases proportionally with the increase in temperature below 3 K and decreases with the increase in temperature between 3–5 K,although it increases exponentially with the increase in temperature above 5 K. This result indicates that the decay rate constant of the 2 - anions is controlled by the rate constant for the diffusion of the 2 - anions via one-phonon assisted quantum tunneling below 3 K,two-phonon scattered or assisted quantum tunneling between 3–5 K,and thermally-activated process above 5 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021850103903
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  • 17
    Electronic Resource
    Electronic Resource
    Computer simulation of A2/B2 second-order phase transition based upon the Khachaturyan diffusion equation (1997)
    Springer
    Journal of materials science 32 (1997), S. 5797-5804 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A computer simulation, based on the Khachaturyan diffusion equation, is presented to develop the kinetics of the morphological evolution of the A2/B2 second-order phase transition in a binary solid solution. The evolution of the occupation probability, as a function of composition, shows a good similarity to the actual micrographs experimentally obtained based on the macroscopic composition gradient method. These results are used in parallel with the results of the evolution of the long-range order parameter as a function of the ageing time, to verify a new concept of the ordering behaviour inside the ordered phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018634204712
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  • 18
    Electronic Resource
    Electronic Resource
    Experimental and theoretical phase diagrams of the iron-rich Fe-Si-Ge ordering system (1995)
    Springer
    Journal of materials science 30 (1995), S. 5056-5064 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The phase separation in iron-rich Fe-Si-Ge ternary alloys was investigated by means of transmission electron microscopy. The phase separations into A2 and D03 were recognized in several alloys in addition to the phase separation into B2 and D03 which has already been found in Fe-Si and Fe-Ge binary systems. On the basis of TEM observations, isothermal section diagrams are proposed for the iron-rich corner at 823, 873, 923 and 973 K. The A2 + D03 two-phase field exists in a band-shaped region at 823 K. With increase in temperature,the A2 + D03 field gradually shrinks and is eventually replaced at 973 Kwith the B2 + D03 field, which extends from both the Fe-Si and Fe-Ge binary sides. The phase diagrams were well reproduced by the calculations based on the so-called Bragg-Williams-Gorsky approximation, taking account of the chemical and magnetic pair interactions up to the second nearest neighbour. The effects of the magnetism on the equilibria are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00356049
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  • 19
    Electronic Resource
    Electronic Resource
    A new parameter for describing the structure bifurcation in two-phase alloys containing coherent particles (1992)
    Springer
    Journal of materials science 27 (1992), S. 6291-6298 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The so-called bifurcation diagrams for γ′ precipitate particles in nickel-based alloys were obtained by calculating the energy state for a pair of particles on the basis of the bifurcation theory. Based on the bifurcation diagrams, we have proposed a new parameter for describing the two-phase structure containing coherent particles. The parameter is defined as the mean particle radius at the intersection of the energy ridge and the line ofR=−0.5 orR=0.5 in the bifurcation diagram (R≡(r α−r β)/(r α+r β), wherer α andr β are the radii of α and β), and is symbolized by¯r * ±0.5. Because the energy state of the paired α and β is maximum at¯r * ±0.5 whenR=±0.5,¯r * ±0.5 is just like the watershed and hence we have termed it “structureshed”. This parameter successfully describes the effects of elastic energy as well as surface energy on the microstructural changes during coarsening of precipitate particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00576274
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  • 20
    Electronic Resource
    Electronic Resource
    Experimental and theoretical studies on phase separations in the Fe-Al-Co ordering alloy system (1994)
    Springer
    Journal of materials science 29 (1994), S. 652-659 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Phase separations in iron-rich Fe-Al-Co ternary alloys were investigated by means of transmission electron microscopy, differential thermal analysis and magnetization measurement. Two kinds of phase separations have been found at 923 K; A2+B2 and B2+B2*. The former occurs in a tongue-shaped composition region ranging from Fe-12 at % Al-15 at % Co to Fe-35 at % Al-45 at % Co and the latter appears in the small region bordering on the Fe-Al binary side of the A2+B2 field. These two-phase fields have theoretically been evaluated on the basis of the so-called Bragg-Williams-Gorsky model taking account of not only chemical but also magnetic interactions. The magnetic ordering accounts for the expansion of the A2+B2 coexistent region. In the measurement of magnetic properties, large increases in coercive force, H c, and residual magnetic flux density, B r, were observed in the two-phase microstructures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00445974
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