Simultaneous determination of small amounts of carbazole and anthracene in some monosubstituted anthraquinones

Simple separation of carbazole and anthracene from monosubstituted anthraquinones is achieved through the application of the zone-melting technique used biphenyl as a medium. Determination limits for both compounds measured by synchronous fluorimetry are 2 μg g^?1 in 2-methyl-, 2-ethyl-, 1-hydroxy- and 1-chloroanthraquinones, and 10 μg g^?1 in another four derivatives.     

High-fidelity teleportation beyond the no-cloning limit and entanglement swapping for continuous variables

We experimentally demonstrate continuous-variable quantum teleportation beyond the no-cloning limit. We teleport a coherent state and achieve the fidelity of 0.70 +/- 0.02 that surpasses the no-cloning limit of 2/3. Surpassing the limit is necessary to transfer the nonclassicality of an input quantum state. By using our high-fidelity teleporter, we demonstrate entanglement swapping, namely, teleportation of quantum entanglement, as an example of transfer of nonclassicality.     

Potentiation of ifosfamide toxicity by chlordiazepoxide, diazepam and oxazepam

The effects of chlordiazepoxide, diazepam and oxazepam on the lethal toxicity and metabolic activation of ifosfamide were investigated in mice. Ifosfamide was administered 24 h after the final injection of chlordiazepoxide, diazepam or oxazepam (100 mg/kg/d for 3 d, i.p.). The prior administration of chlordiazepoxide, diazepam or oxazepam enhanced the toxicity of ifosfamide (778 mg/kg, i.p.) during observation for 6 d after the administration of ifosfamide. In chlordiazepoxide-, diazepam- or oxazepam-treated mice, a higher concentration of active metabolite in the plasma after the administration of ifosfamide (200 or 600 mg/kg, i.p.) was observed as compared with that in mice treated with ifosfamide alone. On the other hand, chlordizepoxide, diazepam or oxazepam markedly enhanced the activity of ifosfamide oxidase in the liver microsomes. These results suggest that the potentiation of ifosfamide toxicity is due to stimulation of the metabolic activation of ifosfamide by chlordizepoxide, diazepam and oxazepam.     

Rapid one-step synthesis, characterization and functionalization of silica coated gold nanoparticles

This paper describes a rapid, simple and one-step method for preparing silica coated gold (Au@SiO₂) nanoparticles with fine tunable silica shell thickness and surface functionalization of the prepared particles with different groups. Monodispersed Au nanoparticles with a mean particle size of 16 nm were prepared by citrate reduction method. Silica coating was carried out by mixing the as prepared Au solution, tetraethoxysilane (TEOS) and ammonia followed by microwave (MW) irradiation. Although there are several ways of coating Au nanoparticles with silica in the literature, each of these needs pre-coating step as well as long reaction duration. The present method is especially useful for giving the opportunity to cover the colloidal Au particles with uniform silica shell within very short time and forgoes the use of a silane coupling agent or pre-coating step before silica coating. Au@SiO₂ nanoparticles with wide range of silica shell thickness (5-105 nm) were prepared within 5 min of MW irradiation by changing the concentration of TEOS only. The size uniformity and monodispersity were found to be better compared to the particles prepared by conventional methods, which were confirmed by dynamic light scattering and transmission electron microscopic techniques. The prepared Au@SiO₂ nanoparticles were further functionalized with amino, carboxylate, alkyl groups to facilitate the rapid translation of the nanoparticles to a wide range of end applications. The functional groups were identified by XPS, and zeta potential measurements.     

Flow-injection determination of 9,10-phenanthrenequinone with catalytic photometric detection

A catalytic photometric method with a flow-injection system is described for the determination of 9,10-phenanthrenequinone. It is based on the catalytic effect of 9,10-phenanthrenequinone on the redox reaction of 1,2-dinitrobenzene with formaldehyde under alkaline conditions. 9,10-Phenanthrenequinone at the 5.0 x 10(-8)-5.0 x 10(-6)M level can be determined at a rate of 20 samples/hr. The detection limit is 1.0 x 10(-8)M (40 pg in a 10-microl injection).     

Storage and retrieval of a squeezed vacuum

Storage and retrieval of a squeezed vacuum was successfully demonstrated using electromagnetically induced transparency. The squeezed vacuum pulse having a temporal width of 930 ns was incident on the laser cooled 87Rb atoms with an intense control light in a coherent state. When the squeezed vacuum pulse was slowed and spatially compressed in the cold atoms, the control light was switched off. After 3 mus of storage, the control light was switched on again, and the squeezed vacuum was retrieved, as was confirmed using the time-domain homodyne method.     

Adsorption kinetics of carcinogens to DNA liquid crystalline gel beads

Adsorption behaviors of acridine orange (AO) and biphenyl (BP) to DNA liquid crystalline gel (LCG) beads in aqueous dispersing solution have been studied theoretically and experimentally. A theoretical consideration based on nonequilibrium thermodynamics predicted that the time course of the adsorption process is expressed with a scaled equation, and a scaled number of adsorbed carcinogen molecules ? is expressed with the square root of a scaled immersion time t, ? proportional, variant square root t at early stage, whereas it is expressed with a power law function 1 - ? proportional, variant (te - t)3/2 for ?0 > 1 and an exponential equation ?0 - ? proportional, variant e-t/alpha tau0 for ?0 > 1 at later stages of adsorption. Here, ?0 is the ratio of the initial number of carcinogen molecules in the dispersing solution to the number of the sites of adsorption of carcinogen molecules in the beads, te is the scaled equilibrium time of adsorption, tau0 is a time constant for adsorption, and alpha is a constant. Observed adsorption processes for AO were well expressed by the predicted ones, and the fitting parameters ?0 and tau0 increased with increasing cobalt chloride concentration CCo used for preparation of the beads, and both saturated above CCo > or = 400 mM for the adsorption of AO, whereas the adsorption processes for BP were expressed with the square root function. These results indicate that (1) the adsorption process at early stage is explained by diffusion-limited binding of the carcinogen molecules to DNA beads, and the time range of the early stage depends on the solubility (the solubility of AO in water is high whereas that of BP is low); and (2) the process at later stages depends on the balance of the numbers of adsorption sites and carcinogen molecules.     

Reactions of sterically congested 1,6‐ and 1,7‐bis(diazo)alkanes with elemental sulfur and selenium: Formation of cyclohexene, 1,2‐dithiocane, 1,2‐diselenocane,and 1,2,3‐triselenecane derivatives

The reaction of 3,8‐bis(diazo)‐2,2,4,4,7,7,9,9‐octamethyldecane ( 5 ) with elemental selenium in 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) at 130°C yielded 1,2‐di‐tert‐butyl‐3,3,6,6‐tetramethylcyclohexene ( 1 ) (64%) and trans‐3,8‐di‐tert‐butyl‐4,4,7,7‐tetramethyl‐1,2‐diselenocane ( 8 ) (13%), while that of 5 with elemental sulfur in DBU gave trans‐3, 8‐di‐tert‐butyl‐4,4,7,7‐tetramethyl‐1,2‐dithiocane ( 9 ) (77%). The reaction of 3,9‐bis(diazo)‐2,2,4,4,8,8,10,10‐octamethylundecane ( 6 ) with elemental selenium in DBU at 80°C gave a cyclic triselenide, cis‐4,10‐di‐tert‐butyl‐5,5,9,9‐tetramethyl‐1,2,3‐triselenecane ( 11 ), in 15% yield as the only identifiable product. The structures of 9 and 11 were confirmed by X‐ray crystallography. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:351–356, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10046     

Resveratrol oligomers and their O-glucosides from Cotylelobium lanceolatum

Three new resveratrol oligomers, cotylelophenol C (1) (resveratrol tetramer) and cotylelosides A (2) and B (3) (O-glucosides of resveratrol trimer), together with four known glucosides of resveratrol oligomers (vaticasides A, B, C, D) and piceid, were isolated from an acetone soluble part of stem of Cotylelobium lanceolatum (Dipterocarpaceae). The structures of new compounds were determined by spectral data analysis. The characteristic properties observed in the NMR spectra of 1 were also discussed.