Quantitative determination of tertatolol in biological fluids by gas chromatography-mass spectrometry

Quantitative determination of tertatolol concentrations in plasma and urine was performed by gas chromatography-mass spectrometry in the chemical-ionization mode with ammonia after successive extractions of the beta-blocking drug in alkaline, acid and final alkaline medium. [2H9]Tertatolol, isotopically stable under the operating conditions employed, was used as an internal standard, thus allowing quantities of 1 ng/ml to be specifically determined. Overall analytical error was less than 10%. Prior to isothermal chromatography at 240 degrees C on a column packed with 3% SE-30, both compounds were silylated with bis(trimethylsilyl)trifluoroacetamide. Detection was performed by monitoring the quasimolecular ions of tertatolol, m/z 368 and m/z 377, for the [2H9]tertatolol in the chemical-ionization mode with ammonia. The calibration curves obtained had linear characteristics for the concentration range 1-1125 ng/ml.     

Influence of chelating agents in eluent on the separation factor of lithium isotopes

The influence of chelating agents on the separation factor, , of lithium isotopes separation was studied by ion exchange elution chromatography. Eluents contained the chelating agent having different number of coordination sites. The chelating agents used in eluent were Na-glycine (Na–Gly), 2Na-iminodiacetic acid (2Na-IDA), 3Na-nitrilotriacetic acid (3Na-NTA), and 4Na-ethylenediaminetetraacetic acid (4Na-EDTA). The ion exchanger was Dowex 50W-X8, sulfonic acid type, sodium form. As a result,⁶Li was enriched in resin phase, and⁷Li was in solution phase. The separation factor, , was gradually increased with increasing number of coordination site (=1.0022–1.0038) at the same distribution coefficient and with increasing distribution coefficients (=1.0017–1.0026) at the same concentration of chelating agents.     

[(Fe/Pt/Fe)/Ag]n多层膜低温合成分离的L10相FePt纳米颗粒

制备了［（Fe/Pt/Fe）/Ag］n多层膜,研究了不同温度退火后的微结构和磁特性.实验结果表明温度高于400℃退火后,样品开始形成L10相的FePt纳米颗粒与Ag基体的复合结构.ΔM曲线的测量表明FePt颗粒之间不存在交换作用,非常清楚地说明非磁基体Ag有效地隔离了FePt磁性颗粒.有序相的低温合成可能和多层膜结构所造成的界面扩散以及Ag层引入的界面缺陷有关,同时,Ag原子较强的迁移性以及FePt与Ag之间表面自由能的显著差异,使FePt纳米颗粒被Ag隔离. 关键词： L10相 FePt 交换作用     

Construction of a natural partition of incomplete horseshoes

We present a method for constructing a partition of an incomplete horseshoe in a Poincare map. The partition is based only on the unstable manifolds of the outermost fixed points and eventually their limits. Consequently, this partition becomes natural from the point of view of asymptotic scattering observations. The symbolic dynamics derived from this partition coincides with the one derived from the hierarchical structure of the singularities of the scattering functions.     

Release of N(2) from the carbon nanotubes via high-temperature annealing

Nitrogen (N)-doped carbon nanotubes (CNTs) were heated to 1000 degrees C under an ultrahigh vacuum. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) reveal three different N structures; graphitelike, pyridine-like, and molecular N(2). The vibrationally resolved XANES peaks of N(2) were first observed, suggesting the existence of molecular N(2) as intercalated and trapped forms. The annealing process can decrease the average N content from 6.3 at. % to 3.3 at. %, mainly by releasing molecular N(2). Electron energy-loss spectroscopy (EELS) confirms that the annealing releases molecular N(2) from the CNTs.     

Depositional characteristics of metal coating on single-crystal TiO2 nanowires

Ultralong single-crystalline TiO(2) nanowires were prepared by a simple, low-cost solvothermal process. Silver nitrate, neodymium chloride, ceric nitrate, stannic chloride hydrate, and cadmium chloride were used as metal sources and deposited by reduction on the surface of TiO(2) nanowires. The composites were subsequently characterized by transmission electron microscopy, and their coverage was compared. The nature of the coatings on the TiO(2) nanowires varies from metal to metal. A novel approach on modified one-dimensional nanostructures with metal coating was developed, which has great potential applications in catalysts, sensors, and nanoscale devices.     

Strong coupling in a microcavity LED

Thin films of polyelectrolyte/J aggregate dye bilayers with high absorption coefficient (6 nm thick with alpha approximately equal to 1.0 x 10(6) cm(-1)) inserted in an optical microcavity enable the cavity quantum electrodynamic strong coupling limit to be reached at room temperature with a coupling strength (Rabi splitting) of 265 +/- 15 meV. By embedding these films in a resonant cavity organic LED structure, we demonstrate the first emissive electrically pumped exciton-polariton device.     

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).     

Sharp decay rates for the fastest conservative diffusions

In many diffusive settings, initial disturbances will gradually disappear and all but their crudest features — such as size and location — will eventually be forgotten. Quantifying the rate at which this information is lost is sometimes a question of central interest. Here this rate is addressed for the fastest conservative nonlinearities in the singular diffusion equation

$u_t=\mathrm{\Delta }(u^m),{(n?2)}_{+}/n<m?n/(n+2),u,t?0,\mathbf{x}\in {\mathbf{R}}^n,$

which governs the decay of any integrable, compactly supported initial density towards a characteristically spreading self-similar profile. A potential theoretic comparison technique is outlined below which establishes the sharp $1/t$ conjectured power law rate of decay uniformly in relative error, and in weaker norms such as $L^1({\mathbf{R}}^n)$. To cite this article: Y.J. Kim, R.J. McCann, C. R. Acad. Sci. Paris, Ser. I 341 (2005).