Artificial Coherent States of Light by Multiphoton Interference in a Single-Photon Stream.

Coherent optical states consist of a quantum superposition of different photon number (Fock) states, but because they do not form an orthogonal basis, no photon number states can be obtained from it by linear optics. Here we demonstrate the reverse, by manipulating a random continuous single-photon stream using quantum interference in an optical Sagnac loop, we create engineered quantum states of light with tunable photon statistics, including approximate weak coherent states. We demonstrate this experimentally using a true single-photon stream produced by a semiconductor quantum dot in an optical microcavity, and show that we can obtain light with g^{(2)}(0)→1 in agreement with our theory, which can only be explained by quantum interference of at least 3 photons. The produced artificial light states are, however, much more complex than coherent states, containing quantum entanglement of photons, making them a resource for multiphoton entanglement.

[Destabilization and stabilization of poly(A).poly(U) structure by platinum(II) compounds].

On the basis of molecular biophysics, a methodology for the analysis of intramolecular structural order of the polynucleotide duplex poly(A).poly(U) has been developed. It was shown that the combination of circular dichroism spectroscopy with differential scanning calorimetry is an optimal approach, which ensures the screening of a wide set of substances and interaction conditions and the choice of compound(s) that can stabilize the structure and increase the biological activity of this duplex. The study is aimed at obtaining a new and highly active antiviral remedy.

Analysis of the 237Np-233Pa photon spectrum using the full response function method.

A study has been made of X- and gamma-ray emission from 237Np in equilibrium with 233Pa using the full response function method. This analysis process is characterised by photon spectrometry in which the entire spectrum is modelled in a pseudo-empirical way by means of elementary functions describing the total absorption and escape peaks, the Compton diffusion internal and external to the detector and the peaks resulting from detection of internal conversion electrons. This method has been applied to determine the L X-, K X- and gamma-rays emission probabilities in 237Np and 233Pa decay studies.

[Influence of the activator of transcription GAL4 on growth and development of embryos and embryonic cells in primary cultures of sand dollar]. / Vliianie aktivatora transkriptsii GAL4 na rost i razvitie émbrionov i émbrional'nykh kletok v pervichnykh kul'turakh ploskogo morskogo ezha.

In order to solve many tasks of biotechnology, constant lines of the cells of marine invertebrates with a high growth potential are required, which are absent at present. We used the universal activator of transcription gal4 to change the degree of expression of genes of growth factors in embryonic sea urchin cells and, thereby, increase their proliferative activity. The fertilized sea urchin eggs and dissociated embryonic cells at the blastula stage were treated with plasmids containing both the functional gene gal4 and the gene devoid of the regions encoding the activator domain. The transfection of embryonic sea urchin eggs with the functional gene led to cell dedifferentiation and formation of tumor-like structures in the embryos or increased number of embryonic cells in culture. In the cells obtained from the transfected embryos, the pigments were found within two months of cultivation, whose absorption spectrum coincided with that of echinochrome.

[Comparison of DNA complexation with antitumor therapeutic cis-DDP and binuclear bivalent platinum compound containing pyrazine]. / Sravnenie kompleksoobrazovaniia DNK s protivoopukholevym preparatom tsis-DDP i biiadernym soedineniem dvykhvalentnoi platiny, soderzhashchim pirazin.

Conformational properties of DNA molecule upon its complexation with binuclear compounds of bivalent platinum in the cis configuration containing pyrazine ligand were studied by circular dichroism, viscometry, and dynamic birefringence. Comparison with active antitumor therapeutic cis-diamminedichloroplatinum (cis-DDP) was made. Experimental data indicates that interaction of these compounds with DNA results in the formation of coordination bond of platinum with nitrogen bases. The structure of the complex depends on the ratio of platinum and DNA concentrations in initial solution. The study of DNA protonation in complex with the binuclear coordination compound showed that the binding of platinum with DNA bases occurs at the N7 atom of guanine. It was observed a competition between the studied compound and cis-DDP for binding site on DNA. The macromolecule binds stronger to the binuclear platinum compound as compared with cis-DDP.

Emission probabilities of the KX-rays following the decay of 237Np in equilibrium with 233Pa.

Following international EUROMET Project No. 416 and our recent measurement of the emission probabilities of the main gamma-rays of 237Np in equilibrium with 233Pa, a complementary work has been undertaken to determine the photon emission probabilities of the KX-rays associated with the decay of these nuclides. Two different analysis methods have been used: the KX-rays region was analyzed by fitting both Voigt and full response functions. Photon emission probabilities were determined with a relative uncertainty of about 2%.

[Dependence of biological activity of triamine type platinum (II) complexes on their composition and structure]. / Zavisimost' biologicheskoi aktivnosti kompleksov platiny(II) triaminovogo tipa ot ikh sostava i stroeniia.

The growth-inhibiting effect on the roots of maize and cucumber shoots was studied. We tested 53 triamine complexes of platinum (cis*- and trans*-[Pt(NH3)*2LCl]Cl, cis*- and trans*-[PtHx*2LCl]Cl and [PtenLCl]Cl, where Hx is hydroxylamine, en is ethylenediamine, and L are various heterocycles, which either have biological activity and occur in the cells or have no biological activity and are foreign to the cells). The cis*-[Pt(NH3)*2LCl]Cl and [PtenLCl]Cl complexes showed cytostatic properties, and the latter were effective at higher concentrations. Small changes in the composition of ligand L led to marked changes in the biological activity of the complexes. In order to characterize the effect of the complexes, we first determined the time of development of the lateral root from its initial appearance to its divergence from the main root (Tlat). The complexes with cytostatic properties markedly inhibited root branching and increased Tlat. The other complexes had virtually no effect on Tlat and reduced the zone of lateral roots only at the expense of inhibition of the main root growth. The complexes with cytostatic properties markedly inhibited the main root growth with time. Parallel studies conducted in the Oncological Research Center, Russian Academy of Medical Sciences have shown that the complexes with cytostatic properties display distinct antitumor activity.