Synthesis and study of thioglycoside conjugates of 4-chloro-1,2-dithiol-3-one as potential cancer-preventive substances in vitro and in vivo

Russian Chemical Bulletin - Nucleophilic substitution of the chlorine atom in 4,5-dichloro-1,2-dithiol-3-one using 1-thio-β-d-glucopyranose and its 2,3,4,6-tetra-O-acetyl derivative in...     

Entanglement of a photon and a collective atomic excitation

We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After a programmable delay, the atomic excitation is converted into a photon (idler). Polarization states of both the signal and the idler are recorded and are found to be in violation of the Bell inequality. Atomic coherence times exceeding several microseconds are achieved by switching off all the trapping fields--including the quadrupole magnetic field of the magneto-optical trap--and zeroing out the residual ambient magnetic field.     

Violation of Bell's inequality by a generalized einstein-podolsky-rosen state using homodyne detection

Using homodyning with weak coherent fields and photon counting, we have observed violations of Bell-type inequalities by the generalized Einstein-Podolsky-Rosen state produced in a pulsed nondegenerate optical parametric amplifier, as predicted by Grangier et al. [Phys. Rev. A 38, 3132 (1988)]. The maximum observed visibility of the interference pattern was (89+/-4)%. This interference can be regarded as a manifestation of nonlocality in the sense described by Banaszek and Wodkiewicz [Phys. Rev. A 58, 4345 (1998)]. We have investigated the interference both theoretically and experimentally and have measured the influence of dispersion and phase matching.     

Mössbauer effect in f.c.c. Fe-Ni-C alloys after the ultrasonic impact surface treatment

M?ssbauer spectroscopy was used for study of the f.c.c. Fe-30.5%Ni-1.5%C, Fe-30.0%Ni-1.3%C, Fe-30.1%Ni-0.44%Mn-1.22%C, Fe-30.3%Ni alloys after the heat treatment at 1373 K in vacuum and the impact ultrasonic surface treatment in vacuum. The vibration amplitude of the magnetostrictor-wave guide-sample system on the (1–3)kHz frequencies was 20 μm and 28 μm corresponding to the power of impacts of 2.4 and 4.7 J/s. In order to show the redistribution process of carbon under the treatment, the ageing of the Fe-30.0%Ni-1.3%C alloy was carried out at 773 K in vacuum. As shown, the ultrasonics of smaller power does not result in distinctive changes in the hyperfine magnetic structure and solid solution state. The increase of power of impacts does not change the phase composition of the alloys except the atomic redistribution in a solid solution varying the electron spin and charge densities on iron nuclei. The results were analyzed in comparison with the data derived after the low-frequency impact surface treatment. Presented at International Colloquium “M?ssbauer Spectroscopy in Materials Science”, Všemina, Czech Republic, June 1–4, 2004. The Science and Technology Center in Ukraine (project #2412) and partially budget program supported this work.     

Syntheses of the marine alkaloids 6-oxofascaplysin,fascaplysin and their derivatives

A simple approach towards the pyrido[1,2-a:3,4-b′]diindole system via the reaction of indigo with methylene active compounds was used for the syntheses of the marine alkaloids 6-oxofascaplysin, fascaplysin, and their derivatives. It was also demonstrated that the reaction with ketones led to indigo decomposition and the formation of isatin derivatives. The derivative of fascaplysin with a phenyl substituent at C-7 demonstrated 2–3 times greater inhibitory activity against selected cancer cell lines than fascaplysin.     

Changes in the adsorption activity of metal oxyhydroxide hydrogels during their ageing in electrolyte solutions

Adsorption properties of Ti(IV), Zr(IV), In(III), Cr(III) and Fe(III) oxyhydroxides aged in sodium chloride and sulphate solutions have been studied. The main research method was determination the rates of heterogeneous hydrolysis reactions for RhCl₆³⁻ and IrCl₆²⁻ complexes. The rate constants of these reactions were a measure of adsorption activity of the oxyhydroxides on which surface they occur. For comparison the corresponding data for freshly formed oxyhydroxides are presented. It was found that adsorption activity (the values of rate constants K_obs) of ferro- and indiogels decrease slowly with increasing of duration and temperature of ageing. The sulphate electrolyte promotes the decrease of sorption activity more than chloride electrolyte. In contrast, the samples of titano- and chromogels aged during 2 h at 80°C have much greater adsorption activity than freshly formed ones, and this activation holds for a very long time. The zirconogel keeps in these conditions stable adsorption activity for a very long time. Apparently, after precipitation the chromo-, titano- and zirconogels some metastable non-crystalline or micro-crystalline structures stable to further ageing form rapidly. The oxyhydroxides behaviour is obviously connected with the electronic structure of outer electronic shell of their central ions. The chromium(III) oxyhydroxide with a unsymmetrical, partially filled 3d-sublevel is the most effective sorbent and has the most stable sorption properties.     

A novel method for the synthesis of 9-[[2-hydroxy-1-(aminomethyl)ethoxy]methyl]guanine - a potential antiviral agent

9-[[2-Hydroxy-1-(aminomethyl)ethoxy]methyl]guanine (1a), an amino analogue of 9-[[2-hydroxy-1-(hydroxymethyl)-ethoxy]methyl]guanine (I) which is a potent antiviral agent, has been synthesized $\text{via}$ a multistep-synthesis.     

Nonsymmetric entanglement of atomic ensembles

The entanglement of multiatom quantum states is considered. In order to cancel noise due to inhomogeneous light-atom coupling, the concept of matched multiatom observables is proposed. As a means to eliminate an important form of decoherence this idea should be of broad relevance for quantum information processing with atomic ensembles. The general approach is illustrated on the example of rotation angle measurement, and it is shown that the multiatom states that were thought to be only weakly entangled can exhibit near-maximum entanglement.     

Dual-species matter qubit entangled with light

We propose and demonstrate an atomic qubit based on a cold 85Rb-87Rb isotopic mixture, entangled with a frequency-encoded optical qubit. The interface of an atomic qubit with a single spatial light mode, and the ability to independently address the two atomic qubit states, should provide the basic interferometrically robust element of a quantum network.     

Dephasing of multiparticle Rydberg excitations for fast entanglement generation

An approach to fast entanglement generation based on Rydberg dephasing of collective excitations (spin waves) in large, optically thick atomic ensembles is proposed. Long-range 1/r(3) atomic interactions are induced by microwave mixing of opposite-parity Rydberg states. The required long coherence times are achieved via four-photon excitation and readout of long wavelength spin waves. The dephasing mechanism is shown to have favorable, approximately exponential, scaling for entanglement generation.