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831.
832.
Silvia Hartzstein Oscar Salinas 《Journal of Mathematical Analysis and Applications》2008,342(2):950-969
In this paper we characterize the weighted BMO(ω)(X), with X a space of homogeneous type, through an adequate weighted Carleson measure. As a byproduct we can define the weighted Triebel-Lizorkin space and obtain the identification with the above space. 相似文献
833.
834.
We study the translational friction coefficients of a spherical micrometric probe moving in nematic liquid crystalline fluids, by solving numerically the constitutive hydrodynamic equations of uncompressible isothermal nematic fluids (Leslie–Ericksen equations). The nematic medium is described by a vector field, which specifies the director orientation at each point and by the velocity vector field. Simulations of director dynamics surrounding the moving probe are presented, and the dependence of translational diffusion upon liquid crystal viscoelastic parameters is discussed. The time evolution of director field is studied in the presence of an orienting magnetic field in two characteristic situations, i.e. direction of motion parallel and perpendicular to field. In particular, a detailed analysis is given for the case of a spherical probe in rectilinear motion in nematic MBBA (4-methoxibenzylidene-4′-n-butylaniline), together with a comparison with other nematogens. 相似文献
835.
Olga S. Finikova Dr. Artem Y. Lebedev Dr. Alexey Aprelev Dr. Thomas Troxler Dr. Feng Gao Dr. Carmen Garnacho Dr. Silvia Muro Prof. Robin M. Hochstrasser Prof. Sergei A. Vinogradov Prof. 《Chemphyschem》2008,9(12):1673-1679
High‐resolution images of oxygen distributions in microheterogeneous samples are obtained by two‐photon laser scanning microscopy (2P LSM), using a newly developed dendritic nanoprobe with internally enhanced two‐photon absorption (2PA) cross‐section. In this probe, energy is harvested by a 2PA antenna, which passes excitation onto a phosphorescent metalloporphyrin via intramolecular energy transfer. The 2P LSM allows sectioning of oxygen gradients with near diffraction‐limited resolution, and lifetime‐based acquisition eliminates dependence on the local probe concentration. The technique is validated on objects with a priori known oxygen distributions and applied to imaging of pO2 in cells. 相似文献
836.
Constable EC Housecroft CE Neuburger M Price JR Schaffner S 《Dalton transactions (Cambridge, England : 2003)》2008,(29):3795-3797
Metal-mediated redox-interconversion of the new ligand 2,2':6',2'-terpyridine-6(1H)-thione and the corresponding disulfide allows the programmed assembly of dinucleating ligands. 相似文献
837.
Carlotto S Polimeno A Ferrante C Benzi C Barone V 《The journal of physical chemistry. B》2008,112(27):8106-8113
A stochastic model for the interpretation of the emission fluorescence of 4-( N, N-dimethylamino)benzonitrile (DMABN) is discussed. We proceed by reviewing the stochastic modeling approach ( Polimeno, A. ; Barbon, A. ; Nordio, P. L. ; Rettig, W. J. Phys. Chem. 1994, 98, 12158 ), in which internal degrees of freedom are coupled with an effective solvent relaxation variable. Potential energy surfaces are obtained using a reliable but computationally cost-effective quantum mechanical (QM) approach, and estimates of dissipative parameters are calculated on the basis of direct hydrodynamic arguments. Emission fluorescence is estimated by solving numerically a diffusion/sink/source equation for the stationary population of excited state and compared to emission fluorescence of DMABN measured experimentally. 相似文献
838.
Santagneli SH Schneider J Skripachev I Ribeiro SJ Messaddeq Y 《The journal of physical chemistry. B》2008,112(16):4943-4947
Glasses having the composition (100 - x)As2P2S8-xGa2S3 with x ranging from 0 to 50% were investigated to determine the compositional effect on properties and local structure. The glass transition temperature (Tg) and the stability parameter against crystallization (Tx - Tg) increased with the addition of Ga2S3. The structure of these glasses was probed by Raman scattering, Fourier transform infrared (FT-IR) and 31P nuclear magnetic resonance. On the basis of the observed vibrations and the strength of the 31P-31P homonuclear magnetic dipolar coupling, two scenarios can be proposed for the structural evolution induced by the addition of Ga2S3. For x or= 30% we have depolymerization of the As2P2S8 units and the formation of a network of GaPS4 units with each PS 4/2 unit (Q4) species carrying a single positive formal charge. 相似文献
839.
Sarah K. Wypysek Silvia P. Centeno Till Gronemann Dominik Wöll Walter Richtering 《Macromolecular bioscience》2023,23(8):2200456
Depending on their architectural and chemical design, microgels can selectively take up and release small molecules by changing the environmental properties, or capture and protect their cargo from the surrounding conditions. These outstanding properties make them promising candidates for use in biomedical applications as delivery or carrier systems. In this study, hollow anionic p(N-isopropylacrylamid-e-co-itaconic acid) microgels are synthesized and analyzed regarding their size, charge, and charge distribution. Furthermore, interactions between these microgels and the model protein cytochrome c are investigated as a function of pH. In this system, pH serves as a switch for the electrostatic interactions to alternate between no interaction, attraction, and repulsion. UV–vis spectroscopy is used to quantitatively study the encapsulation of cytochrome c and possible leakage. Additionally, fluorescence-lifetime images unravel the spatial distribution of the protein within the hollow microgels as a function of pH. These analyses show that cytochrome c mainly remains entrapped in the microgel, with pH controlling the localization of the protein – either in the microgel's cavity or in its network. This significantly differentiates these hollow microgels from microgels with similar chemical composition but without a solvent filled cavity. 相似文献
840.
Pyrolytic graphite electrodes (PGE) were modified into dopamine solutions using phosphate buffer solutions, pH 10 and 6.5, as supporting electrolyte. The modification process involved a previous anodization of the working electrode at +1.5 V into 0.1 mol L−1 NaOH followed by other anodization step, in the same experimental conditions, into dopamine (DA) solutions. pH of the supporting electrolyte performed an important role in the production of a superficial melanin polymeric film, which permitted the simultaneous detection of ascorbic acid (AA), (DA) and uric acid (UA), ΔEAA-DA = 222 mV; ΔEAA-UA = 360 mV and ΔEDA-UA = 138 mV, avoiding the superficial poisoning effects. The calculated detection limits were: 1.4 × 10−6 mol L−1 for uric acid, 1.3 × 10−5 mol L−1 for ascorbic acid and 1.1 × 10−7 mol L−1 for dopamine, with sensitivities of (7.7 ± 0.5), (0.061 ± 0.001) and (9.5 ± 0.05) A mol−1 cm−2, respectively, with no mutual interference. Uric acid was determined in urine, blood and serum human samples after dilution in phosphate buffer and no additional sample pre-treatment was necessary. The concentration of uric acid in urine was higher than the values found in blood and serum and the recovery tests (92-102%) indicated that no matrix effects were observed. 相似文献