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961.
Tomasz Szarek Stanislaw Wedrychowicz 《Proceedings of the American Mathematical Society》2005,133(2):437-440
It is shown that every class of contracting similitudes on satisfying the OSC and such that , where denotes the corresponding fractal, can be extended to an infinite family of contracting similitudes which still satisfies the OSC but the SOSC does not hold.
962.
963.
964.
Zofia Drzazga Katarzyna Michalik Tomasz Halat Anna Michnik Henryk I. Trzeciak 《Journal of Thermal Analysis and Calorimetry》2010,102(1):143-148
Differential scanning microcalorimetry (DSC) and UV–VIS absorption spectroscopy were used to obtain the characteristics of
blood serum from newborn rat’ after maternal treatment with cyclophosphamide in comparison with control. The obtained DSC
curves reveal a complex endothermic peak due to the unfolding process of various serum proteins. Thermal profiles and absorption
spectra of blood serum are sensitive to the age of newborns as well as to effect of maternal administration of cyclophosphamide.
The most significant disturbances in serum proteome were observed for 14-day old newborns. The thermodynamic parameters: enthalpy
change (∆H), the normalized first moment (M1) of the thermal transition with respect to the temperature axis and the ratio of C
pex at 70 and 60 °C describing denaturation contributions of globulin forms in respect to unliganded albumin with haptoglobin
was estimated. Moreover, the second derivative spectroscopy in the UV region was used to resolve the complex protein spectrum.
The differences in blood serum detected by DSC and UV–VIS confirm a potential usefulness of these methods for diagnostic and
monitoring changes with age as well as the pathological state of blood serum. 相似文献
965.
966.
Gustavo Dominguez-Espinosa Tomasz Halamus Piotr Wojciechowski Lidia Okrasa Aleksandra Wypych 《Journal of Non》2011,357(3):986-991
In this paper, dielectric spectroscopy investigations of organic–inorganic hybrid composite obtained from (2-hydroxypropyl)cellulose (HPC) with nanosheet crystallites of quasi-TiO2 are presented. This hybrid belongs to the class of composites, which have no covalent bonds between organic and inorganic constituents and the behaviour of composite is determined mainly by interface of two constituents. The analysis of the molecular dynamics of the hybrid system reveals the influence of the nanosheet crystallites of quasi-TiO2 on the relaxation processes of HPC matrix. The relaxation strength of γ process strongly increases in composite as compared to neat HPC. A shift to higher temperature has been evidenced in the case of α and β processes. A higher value of the slope of the maximum frequency vs. the inverse temperature for the α-relaxation of the composite has been observed. At high temperatures the mesomorphic behaviour of HPC has been drastically reduced in the composite. The results of our investigations are interpreted in terms of a presence of intermolecular forces between HPC and nanosheet crystallites of quasi-TiO2. 相似文献
967.
M Zhong EK Kim JP McGann SE Chun JF Whitacre M Jaroniec K Matyjaszewski T Kowalewski 《Journal of the American Chemical Society》2012,134(36):14846-14857
Novel nanoporous nitrogen-enriched carbon materials were prepared through a simple carbonization procedure of well-defined block copolymer precursors containing the source of carbon, i.e., polyacrylonitrile (PAN), and a sacrificial block, i.e., poly(n-butyl acrylate) (PBA). The preparation of nitrogen-enriched nanocarbons with hierarchical pore structure was enabled by the high fidelity preservation of the initial phase-separated nanostructure between two polymer blocks upon carbonization. Supercapacitors fabricated from the prepared carbons exhibited unusually high capacitance per unit surface area (>30 μF/cm(2)) which was attributed to the pseudocapacitance resulting from the high nitrogen content originating from the PAN precursor. Electrochemical availability of the nitrogen species was also evident from the results of oxygen reduction experiments. The hierarchical pore structure and the high nitrogen content in such materials make them particularly promising for use in supercapacitor and electrocatalyst applications. 相似文献
968.
Charge stabilization improves the numeric performance of double ionization potential equation-of-motion (EOM-DIP) method when using unstable (autoionizing) dianion references. However, the stabilization potential introduces an undesirable perturbation to the target states' energies. Here we introduce and benchmark two approaches for removing the perturbation caused by the stabilization. The benchmark calculations of excitation energies in selected diradicals illustrate that the so-called core correction based on evaluating the perturbation in a small basis set is robust and yields reliable EOM-DIP values, i.e., the errors of 0.0-0.3 eV against a similar-level coupled-cluster approach. 相似文献
969.
Wojciech Szczolko Lukasz Sobotta Piotr Fita Tomasz Koczorowski Michal Mikus Maria Gdaniec Aleksandra Orzechowska Kvetoslava Burda Stanislaw Sobiak Marcin Wierzchowski Jadwiga Mielcarek Ewa Tykarska Tomasz Goslinski 《Tetrahedron letters》2012,53(16):2040-2044
The synthesis and physicochemical properties of novel porphyrazines possessing an alternate system of two peripheral substituents, 2,5-dimethylpyrrol-1-yl and dimethylamino, are presented. All the macrocycles were subjected to HPLC purity studies. Spectroscopic studies of magnesium(II) porphyrazine encompassed steady state absorption, emission measurements, including fluorescence decays, transient absorption spectra, and thermoluminescence. Additionally, magnesium(II) porphyrazine was found to be a moderate photosensitizer with singlet oxygen generation values of 0.12 and 0.14 in DMF and DMSO, respectively. Comparison of the quantum yields of singlet oxygen generation before and after deoxygenation showed that the photodynamic effect of magnesium(II) porphyrazine is governed by the photosensitization mechanism II. Magnesium(II) and manganese(III) porphyrazines were characterized using X-ray crystallography. 相似文献
970.
Tomasz Bereźniak Andres Jäschke Jeremy C. Smith Petra Imhof 《Journal of computational chemistry》2012,33(19):1603-1614
The Diels‐Alderase ribozyme is an in vitro‐evolved ribonucleic acid enzyme that catalyzes a [4 + 2] cycloaddition reaction between an anthracene diene and a maleimide dienophile. The ribozyme can in principle be used to selectively synthesize only one product enantiomer, depending on which of the two entrances to the catalytic pocket, “front” or “back”, the substrate is permitted to use. Here, we investigate stereoselection and substrate recognition in the ribozyme by means of multiple molecular dynamics simulations, performed on each of the two substrates individually in the pocket, on the reactant state, and on the product state. The results are consistent with a binding mechanism in which the maleimide likely binds first followed by the anthracene, which enters preferentially through the front door. The free energy profiles for anthracene binding indicate that the pre‐(R,R)‐enantiomer conformation is slightly preferred, in agreement with the experimentally observed small enantiomeric excess of the (R,R)‐enantiomer of the product. The reactant state is stabilized by the simultaneous presence of both substrates bound to their binding sites in the hydrophobic pocket as well as by stacking interactions between them. © 2012 Wiley Periodicals, Inc. 相似文献