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11.
Elena Buixaderas Elena Maria Anghel Simona Petrescu 《Journal of solid state chemistry》2010,183(9):2227-2235
Composites in the TiB2-Na2O·B2O3·Al2O3 systems, TiB2-MBA (MB stands for sodium metaborate and A is Al2O3), were prepared by self-propagating high-temperature synthesis (SHS), in simultaneous mode. Selection of these compositions was ruled by the interesting properties of both TiB2 and double borates of alkali metal and aluminum. The structure of the obtained materials was evaluated by micro-Raman spectroscopy, from room temperature up to 600 °C, and X-ray photoelectron spectroscopy (XPS). Formation of the TiB2 and TiO2−xBx phases along with TiO2 as rutile were identified as titanium speciation in the grain phase embedded in a sodium aluminum borate matrix. Integration of the Raman spectra of the grain phases revealed a TiB2 content of 16.99% and 23.32% for the two composite investigated 2TiB2·2MBA and 3TiB2·5MBA. A constrained-width model for the spectral deconvolution of the high-frequency Raman band was forwarded to calculate the proportion of tetrahedral boron atoms (7.424%) in the blank borate matrix Na2B2O4·Al2O3 in solid phase. 相似文献
12.
E. Gyorgy S. Grigorescu I.N. Mihailescu A. Dindune Z. Kanepe E. Palcevskis S.M. Petrescu 《Applied Surface Science》2007,253(19):7981-7986
Bioactive glass (BG), calcium hydroxyapatite (HA), and ZrO2 doped HA thin films were grown by pulsed laser deposition on Ti substrates. An UV KrF* (λ = 248 nm, τ ≥ 7 ns) excimer laser was used for the multi-pulse irradiation of the targets. The substrates were kept at room temperature or heated during the film deposition at values within the (400-550 °C) range. The depositions were performed in oxygen and water vapor atmospheres, at pressure values in the range (5-40 Pa). The HA coatings were heat post-treated for 6 h in a flux of hot water vapors at the same temperature as applied during deposition. The surface morphology, chemical composition, and crystalline quality of the obtained thin films were studied by scanning electron microscopy, atomic force microscopy, and X-ray diffractometry. The films were seeded for in vitro tests with Hek293 (human embryonic kidney) cells that revealed a good adherence on the deposited layers. Biocompatibility tests showed that cell growth was better on HA than on BG thin films. 相似文献
13.
We have directly time resolved the lattice motions associated with the formation of the self-trapped exciton in the quasi-one-dimensional system [Pt(en)(2)] [Pt(en)2Br2];(PF6)(4) ( en = ethylene-diamine, C2H8N2), using femtosecond impulsive excitation techniques. A strongly damped, low-frequency wave packet modulation at approximately 110 cm(-1) accompanies the formation of the self-trapped exciton on a approximately 200 fs time scale following excitation of the intervalence charge-transfer transition. Coherent oscillations at the ground state vibrational frequency and its harmonics are also detected. 相似文献
14.
This paper gives one-term componentwise asymptotics for theM and spectral matrices of a self-adjoint realisation of aneven-order ordinary differential expression. The underlyinginterval is assumed to have at least one regular endpoint, andthe boundary conditions are supposed to be separated. Furthermore,the weight function and the reciprocal of the highest-ordercoefficient are supposed to be of regular variation at the regularendpoint, in the sense of Bingham, Goldie and Teugels. 1991Mathematics Subject Classification: 34B24, 34E05. 相似文献
15.
Lipid diffusion from single molecules of a labeled protein undergoing dynamic association with giant unilamellar vesicles and supported bilayers 总被引:1,自引:0,他引:1
Sharonov A Bandichhor R Burgess K Petrescu AD Schroeder F Kier AB Hochstrasser RM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(3):844-850
It is demonstrated that single-molecule tracking of a fluorescently labeled protein undergoing transient binding to model membranes presents a useful method of obtaining fluid properties. The labeled ACBP protein was tracked during its binding to free-standing giant unilamellar vesicles (GUVs) and supported bilayers prepared from the GUVs in the same environment. The analysis of images that are blurred as a result of fast probe diffusion was discussed. An examination of the lateral diffusion trajectories revealed a homogeneous diffusion on the top segments of the GUVs with D = 6.9 +/- 0.3 microm(2)/s. The supported bilayer experiments revealed two diffusion processes, one with Df = 3.1 +/- 0.4 microm(2)/s and the other with Ds = 0.078 +/- 0.001 microm(2)/s. The 2-fold difference in the lipid bilayer mobility for the free-standing and fast components in the supported bilayers is attributed to the known effect of frictional coupling with the solid support. The slow mobile fraction in the bilayer is suggested to be associated with the migration of pore-like structures, originating from the interaction of the membrane with the glass support. 相似文献
16.
Weihong Lin Ejiofor AD EzekweJr Zhen Zhao Emily R Liman Diego Restrepo 《BMC neuroscience》2008,9(1):114
Background
The main olfactory epithelium (MOE) in the nasal cavity detects a variety of air borne molecules that provide information regarding the presence of food, predators and other relevant social and environmental factors. Within the epithelium are ciliated sensory neurons, supporting cells, basal cells and microvillous cells, each of which is distinct in morphology and function. Arguably, the least understood, are the microvillous cells, a population of cells that are small in number and whose function is not known. We previously found that in a mouse strain in which the TRPM5 promoter drives expression of the green fluorescent protein (GFP), a population of ciliated olfactory sensory neurons (OSNs), as well as a population of cells displaying microvilli-like structures is labeled. Here we examined the morphology and immunocytochemical properties of these microvillous-like cells using immunocytochemical methods. 相似文献17.
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19.
S. GeorgescuO. Toma A.M. VoiculescuC. Matei R. BirjegaL. Petrescu 《Physica B: Condensed Matter》2012,407(7):1124-1127
Bright green (at 525 and 550 nm) and red (at 660 nm) luminescence in Er:Yb:La3Ga5.5Ta0.5O14 (LGT) powder synthesized by solid state reaction was obtained by pumping at 936 nm. Yb3+-Er3+ energy transfer processes accounting for population of the 2H211/2, 4S3/2 and 4F9/2 Er3+ levels are discussed. The dependence of ratio between the intensities of the green and red luminescence on pump intensity is analyzed. The rather high quantum efficiency (58%) of the (4S3/2, 2H211/2) Er3+ emitting level recommends LGT doped with erbium and ytterbium for upconversion applications. 相似文献
20.
Bandichhor R Petrescu AD Vespa A Kier AB Schroeder F Burgess K 《Journal of the American Chemical Society》2006,128(33):10688-10689
A special, water-soluble, fluorescent probe 1 was designed. This consisted of a fluorescein-based component to harvest irradiation at 488 nm and a rhodamine-based part designed to emit it at a significantly longer wavelength. This cassette was used to label an illustrative protein called ACBP. Evidence was accumulated to support the assertion that ACBP-1 bound its native ligand with a binding constant similar to that of the unlabeled protein, and retained its secondary structure (CD). ACBP-1 was imported into cells using the Chariot peptide. Confocal images proved that some ACBP-1 localized into the nucleus (as expected) and, most significantly, it could be visualized more effectively by irradiating at the donor (fluorescein-like) part of the cassette, than the acceptor (rhodamine-like) part. Overall, this study demonstrates that cassettes of this kind can label a protein without significantly perturbing its function or secondary structure and they can be visualized effectively via irradiation of the donor and observation of the acceptor fluorescence. 相似文献