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1.
Leszek Wachowski Antoni Grodzicki Piotr Piszczek Monika Richert Magdalena Hofman 《Reaction Kinetics and Catalysis Letters》2007,91(1):93-99
Hydrogenation of styrene has been applied as a test reaction to study the catalytic activity of TiO2 deposited by the CVD (chemical vapour deposition) method on the surface of a carbonaceous material enriched in nitrogen (CN). 相似文献
2.
The activity of enzyme I (EI), the first protein in the bacterial PEP:sugar phosphotransferase system, is regulated by a monomer–dimer equilibrium where a Mg2+-dependent autophosphorylation by PEP requires the homodimer. Using inactive EI(H189A), in which alanine is substituted for the active-site His189, substrate binding effects can be separated from those of phosphorylation. Whereas 1 mM PEP (with 2 mM Mg2+) strongly promotes dimerization of EI(H189A) at pH 7.5 and 20 °C, 5 mM pyruvate (with 2 mM Mg2+) has the opposite effect. A correlation between the coupling of N- and C-terminal domain unfolding, measured by differential scanning calorimetry, and the dimerization constant for EI, determined by sedimentation equilibrium, is observed. That is, when the coupling between N- and C-terminal domain unfolding produced by 0.2 or 1.0 mM PEP and 2 mM Mg2+ is inhibited by 5 mM pyruvate, the dimerization constant for EI(H189A) decreases from >108 to <5 × 105 or 3 × 107 M−1, respectively. With 2 mM Mg2+ at 15–25 °C and pH 7.5, PEP has been found to bind to one site/monomer of EI(H189A) with KA′106 M−1 (ΔG′=−33.7±0.2 kJ mol−1 and ΔH=+16.3 kJ mol−1 at 20 °C with ΔCp=−1.4 kJ K−1 mol−1). The binding of PEP to EI(H189A) is synergistic with that of Mg2+. Thus, physiological concentrations of PEP and Mg2+ increase, whereas pyruvate and Mg2+ decrease the amount of dimeric, active, dephospho-enzyme I. 相似文献
3.
Janusz Brzdęk Magdalena Piszczek 《Journal of Fixed Point Theory and Applications》2017,19(4):2441-2448
We prove a fixed point theorem for nonlinear operators, acting on some function spaces (of set-valued maps), which satisfy suitable inclusions. We also show some applications of it in the Ulam type stability. 相似文献
4.
Oxo/hydoxo zirconium(IV) complex of the general formula [Zr6(μ3-O)4(μ3-OH)4(OOCCH2tBu)9(μ2-OH)3]2 has been isolated, when Zr(OiPr)4 reacted with a 2-fold excess of 3,3-dimethylbutyric acid. Single crystal X-ray diffraction data, collected at 103 and 153 K, showed that the studied compound crystallizes in hexagonal system (P63/m (no. 176)). Structure consists of dimers composed of [Zr6(μ3-O)4(μ3-OH)4(OOCCH2tBu)9] sub-units, linked by six μ2-OH bridges. Infrared spectroscopic studies proved the presence of hydroxo groups in the structure of studied clusters and formation of different types of oxo/hydroxo bridges. The application of variable temperature infrared spectroscopy and differential scanning calorimetry revealed that the structure of this complex undergoes the phase transitions at 143–183 and 203–293 K. Comparison of spectral and crystallographic data suggests that these phase transitions might be related to changes in the strength of Zr–O bonds of μ2-OH bridges linking complex sub-units, and change in symmetry of the crystal lattice (from hexagonal to trigonal). Analysis of thermogravimetric data showed that decomposition of [Zr6(μ3-O)4(μ3-OH)4(OOCCH2tBu)9(μ2-OH)3]2 proceeds with complete conversion to ZrO2 (monoclinic form) between 603 and 803 K. 相似文献
5.
M. Piszczek K. Rutyna M. Szustakowski 《The European physical journal. Special topics》2008,154(1):153-157
Imaging of space with using optoelectronic observation
system with active illumination is the innovatory detection method and
identification of subtle spatial imaging structure. The paper presents
comparisons of passive and active images methods of registration. Individual
images (photo frame fragment of scene) were registered for different
distances and deepness field of observation. The possibility of control
spatiotemporal frame and results of laboratory investigation and ground
tests were graphically presented. Received results shows on potentially
large measuring and application possibilities methods of observation with
active illumination. 相似文献
6.
Assuming elastic-plastic material behavior the slow growth of Mode III crack under both monotonic and pulsating loadings is considered. Rice's idea of universal R-curve is employed while the mathematical analysis is based on the one-dimensional plasticity model suggested by Kostrov and Nikitin. Motion of a quasi-static Mode III crack is studied and the stable/unstable transition points are found through application of the final stretch failure condition proposed in 1972 by Wnuk. A logarithmic formula for fatigue crack extension rate is derived. Results are compared to other well-known solutions. 相似文献
7.
Magdalena Piszczek 《Aequationes Mathematicae》2013,85(1-2):111-118
We prove that a set-valued function satisfying some functional inclusions admits, in appropriate conditions, a unique selection satisfying the corresponding functional equation. As a consequence we obtain the result on the Hyers–Ulam stability of that functional equation. 相似文献
8.
Hexanuclear oxo titanium(IV) isopropoxide carboxylates, of the general formula [Ti6O6(OPri)6(O2CR)6] (R = But (1), CH2But (2)) and [Ti6O6(OPri)6(O2CC(CH3)2Et)6] · 0.5(C7H8) (3), have been synthesized as polycrystalline powders in order to study their thermal properties and usability as TiO2 CVD precursors. Analysis of thermogravimetric and variable temperature (VT-IR) data shows that the thermal stability of the synthesized complexes decreases as follows 3 > 2 > 1. The composition of the vapors formed during the thermolysis of 1–3 were qualitatively analysed with VT-IR methods and mass spectrometry (MS-EI). According to obtained results, the decomposition of 1 and 2 proceeds with a partial decomposition and the formation of a volatile and stable titanium species, sufficient for their transport in vapors. The formation of volatile titanium-containing derivatives is an important factor that decides the application of 1 and 2 as precursors in CVD experiments. The high stability of 3 causes the thermal decomposition of this complex to be observed just above 573 K, and volatile titanium-containing derivatives were not detected in vapors. These results indicate that 3 could not be used as a precursor in CVD processes. 相似文献
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10.
Grzegorz Piszczek Badri P. Maliwal Ignacy Gryczynski Jonathan Dattelbaum Joseph R. Lakowicz 《Journal of fluorescence》2001,11(2):101-107
We describe multiphoton excitation of the lanthanides europium (Eu3+) and terbium (Tb3+) when these ions are complexed with nucleic acids, proteins, and fluorescent chelators. In all cases excitation occurs by multiphoton absorption of the sensitizers. For the nucleotide GDP and an oligonucleotide with several guanines, the sensitized emission of Tb3+ excited at 776 nm indicated a three-photon process. For Tb3+ bound to the wild-type troponin C and a single tryptophan mutant (26W), excitation at 794 nm was also close to a three-photon process. For lanthanide chelators containing various sensitizers, we observed three-photon excitation in the case of methyl anthranilate, a mixuture of two- and three-photon excitation for carbostyril 124, and a two-photon process with a coumarin derivative. In the case of coumarin-sensitized emission of Eu3+ varied from a two- to a three-photon process at wavelengths ranging from 780 to 880 nm. The sensitized luminescence also shows significantly higher photostability compared to the fluorescence from the organic fluorophores alone. These results suggest the use of multiphoton-induced sensitized lanthanide fluorescence in biochemistry and cellular imaging.On leave from the Institute of Experimental Physics 相似文献