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991.
Khlebtsov BN Panfilova EV Terentyuk GS Maksimova IL Ivanov AV Khlebtsov NG 《Langmuir : the ACS journal of surfaces and colloids》2012,28(24):8994-9002
We describe a novel strategy for the fabrication of plasmonic nanopowders (dried gold nanoparticles) by using wet chemical nanoparticle synthesis, PEG-SH functionalization, and a standard freeze-drying technique. Our strategy is illustrated by successful fabrication of different plasmonic nanopowders, including gold nanorods, gold-silver nanocages, and gold nanospheres. Importantly, the dried nanoparticles can be stored for a long time under usual conditions and then can easily be dissolved in water at a desired concentration without such hard manipulations as sonication or heating. Redispersed samples maintain the plasmonic properties of parent colloids and do not form aggregates. These properties make pegylated freeze-dried gold nanoparticles attractive candidates for plasmonic photothermal therapy in clinical settings. In this work, redispersed gold nanorods were intravenously administered to mice bearing Ehrlich carcinoma tumors at doses of 2 and 8 mg (Au)/kg (animal). Particle biodistribution was measured by atomic absorption spectroscopy, and tumor hyperthermia effects were studied under laser NIR irradiation. Significant tumor damage was observed only at the higher dose of the nanorods. 相似文献
992.
Veselov AA Abraham BG Lemmetyinen H Karp MT Tkachenko NV 《Analytical and bioanalytical chemistry》2012,402(3):1149-1158
Fluorescent proteins have the inherent ability to act as sensing components which function both in vitro and inside living
cells. We describe here a novel study on a covalent site-specific bonding of fluorescent proteins to form self-assembled monolayers
(SAMs) on the surface of etched optical fibers (EOFs). Deposition of fluorescent proteins on EOFs gives the opportunity to
increase the interaction of guided light with deposited molecules relative to plane glass surfaces. The EOF modification is
carried out by surface activation using 3-aminopropylthrimethoxysilane (APTMS) and bifunctional crosslinker sulfosuccinimidyl
4-[N-maleimidomethyl]cyclohexane-1-carboxylate (sulfo-SMCC) which exposes sulfhydryl-reactive maleimide groups followed by covalent
site-specific coupling of modified yellow fluorescent protein (YFP). Steady-state and fluorescence lifetime measurements confirm
the formation of SAM. The sensor applications of YPF SAMs on EOF are demonstrated by the gradual increase of emission intensity
upon addition of Ca2+ ions in the concentration range from a few tens of micromolars up to a few tens of millimolars. The studies on the effect
of pH, divalent cations, denaturing agents, and proteases reveal the stability of YFP on EOFs at normal physiological conditions.
However, treatments with 0.5% SDS at pH 8.5 and protease trypsin are found to denaturate or cleave the YFP from fiber surfaces. 相似文献
993.
Harpham MR Nguyen SC Hou Z Grossman JC Harris CB Mara MW Stickrath AB Kanai Y Kolpak AM Lee D Liu DJ Lomont JP Moth-Poulsen K Vinokurov N Chen LX Vollhardt KP 《Angewandte Chemie (International ed. in English)》2012,51(31):7692-7696
Caught in the light: The fulvalene diruthenium complex shown on the left side of the picture captures sun light, causing initial Ru-Ru bond rupture to furnish a long-lived triplet biradical of syn?configuration. This species requires thermal activation to reach a crossing point (middle) into the singlet manifold on route to its thermal storage isomer on the right through the anti?biradical. 相似文献
994.
A total of twelve novel enantiomerically pure tetra-carbohydrazide cyclophane macrocycles have been synthesised in quantitative yields by reacting chiral (4R,5R)- and (4S,5S)-1,3-dioxolane-4,5-dicarbohydrazides with aromatic bis-aldehydes in a [2 + 2]-cyclocondensation reaction. The compounds show a dynamic behaviour in solution, which has been rationalized in terms of an unprecedented conformational interconversion between two conformers one stabilised by intramolecular hydrogen bonding and π-π stacking interactions. 相似文献
995.
Matano Y Matsumoto K Hayashi H Nakao Y Kumpulainen T Chukharev V Tkachenko NV Lemmetyinen H Shimizu S Kobayashi N Sakamaki D Ito A Tanaka K Imahori H 《Journal of the American Chemical Society》2012,134(3):1825-1839
5-(Diphenylphosphanyl)-10,15,20-triarylporphyrins (meso-phosphanylporphyrins) underwent complexations with palladium(II) and platinum(II) salts to afford phosphapalladacycle- and phosphaplatinacycle-fused coplanar porphyrin dimers, respectively, via regioselective peripheral β-C-H activation of the meso-phosphanylporphyrin ligands. The optical and electrochemical properties of these metal-linked porphyrin dimers as well as their porphyrin monomer/dimer references were investigated by means of steady-state UV-vis absorption/fluorescence spectroscopy, cyclic and differential pulse voltammetry, time-resolved spectroscopy (fluorescence and transient absorption lifetimes and spectra), and magnetic circular dichroism spectroscopy. All the observed data clearly show that the palladium(II) and platinum(II) linkers play crucial roles in the electronic communication between two porphyrin chromophores at the one-electron oxidized state and in the singlet-triplet intersystem-crossing process at the excited state. It has also been revealed that the C-Pt-C linkage makes more significant impacts on these fundamental properties than the C-Pd-C linkage. Furthermore, density functional theory calculations on the metal-linked porphyrin dimers have suggested that the antibonding dπ-pπ orbital interaction between the peripherally attached metal and adjacent pyrrolic β-carbon atoms destabilizes the highest occupied molecular orbitals of the porphyrin π-systems and accounts for the observed unique absorption properties. On the basis of these experimental and theoretical results, it can be concluded that the linear carbon-metal-carbon linkages weakly but definitely perturb the optical, photophysical, and electrochemical properties of the phosphametallacycle-linked coplanar porphyrin dimers. 相似文献
996.
Andrey E. Kovtanyuk Alexander Yu. Chebotarev Nikolai D. Botkin Karl-Heinz Hoffmann 《Journal of Mathematical Analysis and Applications》2014
Conductive–convective–radiative heat transfer in a scattering and absorbing medium with reflecting and radiating boundaries is considered. The P1 approximation (diffusion model) is used for the simplification of the original problem. The existence of bounded states of the diffusion model is proved. The uniqueness of solutions is established under certain assumptions. 相似文献
997.
We consider systems of Euler–Lagrange equations with two degrees of freedom and with Lagrangian being quadratic in velocities. For this class of equations the generic case of the equivalence problem is solved with respect to point transformations. Using Lie?s infinitesimal method we construct a basis of differential invariants and invariant differentiation operators for such systems. We describe certain types of Lagrangian systems in terms of their invariants. The results are illustrated by several examples. 相似文献
998.
The classical theory of Toeplitz operators in spaces of analytic functions deals usually with symbols that are bounded measurable functions on the domain in question. A further extension of the theory was made for symbols being unbounded functions, measures, and compactly supported distributions, all of them subject to some restrictions. 相似文献
999.
Let V denote a finite-dimensional vector space over some field. We say that a linear group G ≤ GL(V) is a linearly Kleiman group if, for every pair of linear subspaces v, u ≤ V, there is an element g ∈ G such that the subspaces g(v), u are in general position. The main result of this paper is the classification of connected linear algebraic groups over a field of characteristic zero which are linearly Kleiman. We also consider some properties of linearly Kleiman groups. 相似文献
1000.
Nikolai Nowaczyk 《Annals of Global Analysis and Geometry》2013,44(4):541-563
It is well known that on a bounded spectral interval the Dirac spectrum can be described locally by a non-decreasing sequence of continuous functions of the Riemannian metric. In the present article, we extend this result to a global version. We view the spectrum of a Dirac operator as a function $\mathbb Z \,\rightarrow \mathbb R \,$ and endow the space of all spectra with an $\mathrm{arsinh }$ -uniform metric. We prove that the spectrum of the Dirac operator depends continuously on the Riemannian metric. As a corollary, we obtain the existence of a non-decreasing family of functions on the space of all Riemannian metrics, which represents the entire Dirac spectrum at any metric. We also show that, due to spectral flow, these functions do not descend to the space of Riemannian metrics modulo spin diffeomorphisms in general. 相似文献