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61.
Katarína Kráľová František Šeršeň Matúš Peško Karel Waisser Lenka Kubicová 《Chemical Papers》2014,68(1):46-52
5-Bromo-(Br-PBA) and 3,5-dibromo-2-hydroxy-N-phenylbenzamides (Br2-PBA) inhibited photosynthetic electron transport (PET) and their inhibitory efficiency depended on the compound lipophilicity as well as on the electronic properties of the R substituent in the N-phenyl moiety. Br-PBA showed higher PET inhibiting activity than Br2-PBA with the same R substituent. The most effective inhibitors in the tested series were the derivatives with R = 3-F (Br-PBA; IC50 = 4.3 μmol dm?3) and R = 3-Cl (Br2-PBA; IC50 = 8.6 μmol dm?3). Bilinear dependence of the PET inhibiting activity on the lipophilicity of the compounds as well as on the Hammett constant, σ, of the R substituent was observed for both investigated series. Using EPR spectroscopy it was found that the site of action of the tested compounds in the photosynthetic apparatus is situated on the donor side of PS 2, in D· or in the Z·/D· intermediates. Interaction of the studied compounds with chlorophyll a and aromatic amino acids present in the pigment-protein complexes mainly in photosystem 2 was documented by fluorescence spectroscopy. 相似文献
62.
Łukasz Wiśniewski Katarína Vaňková Pavel Ačai Milan Polakovič 《Chemical Papers》2014,68(12):1649-1655
Galacto-oligosaccharides are typically produced by an enzymatic reaction when the post-reaction mixture contains considerable amounts of lactose and glucose and a smaller amount of galactose. In order to develop a process of chromatographic removal of saccharide impurities, adsorption equilibria and kinetics of these di- and monosaccharides were investigated for Diaion UBK 530, an industrialgrade strong cation-exchanger in the Na+ form. Frontal chromatographic experiments were carried out in the temperature range of 30–70°C and a broad interval of saccharide concentrations up to 350 g L?1. Breakthrough curves were described using the equilibrium-dispersive model with the linear adsorption isotherm. Both the distribution and the axial dispersion coefficient values depended on the saccharide molecule type and size. No significant effect of temperature or concentration on the distribution coefficient was observed. The apparent dispersion coefficients of all saccharides exhibited some decrease with the temperature, which was caused by the decrease of the intraparticle mass transfer resistance. An analysis showed that both the intraparticle mass transfer and the axial dispersion had a significant influence on the front dispersion. 相似文献
63.
Dr. Shantanu Ganesh Kulkarni Kristýna Jelínková Dr. Marek Nečas Dr. Zdeňka Prucková Dr. Michal Rouchal Dr. Lenka Dastychová Dr. Petr Kulhánek Dr. Robert Vícha 《Chemphyschem》2020,21(18):2084-2095
Stilbene derivatives are well-recognised substructures of molecular switches based on photochemically and/or thermally induced (E)/(Z) isomerisation. We combined a stilbene motif with two benzimidazolium arms to prepare new sorts of supramolecular building blocks and examined their binding properties towards cucurbit[n]urils (n=7, 8) and cyclodextrins (β-CD, γ-CD) in water. Based on the 1H NMR data and molecular dynamics simulations, we found that two distinct complexes with different stoichiometry, i. e., guest@β-CD and guest@β-CD2, coexist in equilibrium in a water solution of the (Z)-stilbene-based guests. We also demonstrated that the bis(benzimidazolio)stilbene guests can be transformed from the (E) into the (Z) form via UV irradiation and back via thermal treatment in DMSO. 相似文献
64.
This paper is devoted to the study of the Hamiltonian dynamics of string in non-relativistic D3-brane background. We discuss different gauge fixing functions and construct corresponding gauge fixed Hamiltonians. 相似文献
65.
66.
Various aspects of the C-metric representing two rotating charged black holes accelerated in opposite directions are summarized
and its limits are considered. A particular attention is paid to the special-relativistic limit in which the electromagnetic
field becomes the “magic field” of two oppositely accelerated rotating charged relativistic discs. When the acceleration vanishes
the usual electromagnetic magic field of the Kerr–Newman black hole with gravitational constant set to zero arises. Properties
of the accelerated discs and the fields produced are studied and illustrated graphically. The charges at the rim of the accelerated
discs move along spiral trajectories with the speed of light. If the magic field has some deeper connection with the field
of the Dirac electron, as is sometimes conjectured because of the same gyromagnetic ratio, the “accelerating magic field”
represents the electromagnetic field of a uniformly accelerated spinning electron. It generalizes the classical Born’s solution
for two uniformly accelerated monopole charges. 相似文献
67.
Jan Remsa Miroslav Jelinek Tomáš Kocourek Ji?í Oswald Marian ?erňanský Michal Jelínek 《Applied Surface Science》2009,255(10):5292-5294
High quality, thick, highly oriented crystalline thin films of Yttrium Aluminum Garnet (Y3Al5O12) and Yttrium Aluminum Perovskite (YAlO3) doped with Erbium were prepared by pulsed laser deposition. Samples were created in vacuum or oxygen environment. Depositions were arranged at room temperature, or at high substrate temperatures ranging from 800 to 1100 °C. Amorphous layers were annealed by laser, or in oven (argon flow, temperatures in range from 1200 to 1400 °C). Fused silica and sapphire (0 0 0 1) were used as substrates. Properties of films were characterized by X-ray diffraction, atomic force microscopy, and by photoluminescence measurement. Size of crystalline grains was in the range 116-773 nm. Thickness of layers was up to 17 μm. 相似文献
68.
69.
P. Vaňura V. Jedináková-Křížová 《Journal of Radioanalytical and Nuclear Chemistry》1998,230(1-2):277-279
The isotope dilution with substoichiometric separation for the determination of strontium has been investigated. Strontium
can be extracted with a substoichiometric amount of bis-1,2-dicarbollylcobaltate in nitrobenzene in the presence of 15-crown-5.
It has been found, that Li+, Mg2+, Ca2+ and Fe3+ do not interfere in the strontium determination but the high extraction of K+, Na+ and NH4
+ ions results in marked influence. 相似文献
70.
Spatially resolved measurements of vibrational and rotational temperature determined from the N2(C) nitrogen bands intensities have been performed by means of optical scanner of original construction. It has been found
that radial variations of studied bands are independent of pressure and discharge current under our experimental conditions,
i.e. in the pressure range (100–300) Pa and for discharge current up to 40 mA. Moreover, it has been found that vibrational
as well as rotational temperatures stay almost constant in the radial direction. No radial changes of both temperatures can
be explained by good thermal conductivity of the positive column of DC glow discharge.
This research was supported by grants: Charles University No. GAUK 194/01, Ministry of Education of Czech Republic MSM 11320002,
and Grant Agency of Czech Republic GAČR 202/03/0827. The theme of presented article was included in the EU project No. G1RT-CT-2002-05083
“Plasmatech”. 相似文献