13C NMR spectra and stereoisomerism in series of androstano-and estrano-D′-pentaranes

Conclusions The stereoisomerism in series of androstano- and estrano-D-pentaranes in solution has been investigated by¹³C NMR. The orientation of the D ring in the 15,16-, 15,16-, and 15,16-isomers relative to the steroid skeleton, as well as the boat conformation of the D ring, were determined from the¹³C chemical shifts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1038–1045, May, 1984.     

Synthesis of 4-hydroxy- and 3-aryl-4-amino- 2-trifluoromethylpyridines

Schemes for synthesizing 3-acyl-4-amino(hydroxy)-2-trifluoromethylpyridines from 3-acyl 4-amino-5,5,5-trifluoro-3-penten-2-ones via their diphenylboron chelate complexes have been suggested.Translated fromlzvestiyn Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2715–2718, November, 1996,     

An NMR study of the allyl rearrangement in boron compounds

The temperature dependence of the PMR spectrum is reported for allyl compounds of boron, nitrogen, and silicon. The allyl rearrangement is observed in triallylboron, allylboracyclopentane, and triallylboron pyridinate. The rate of the rearrangement has been measured as a function of temperature to give the activation energy. A scheme is proposed for the rearrangement in boron compounds.     

Cross sections of 102 element isotopes formation in the reactions of22Ne+236U and26Mg+232Th

The production cross sections of the isotopes²⁵²102,²⁵³102, and²⁵⁴102 were measured for the heavy ion fusion reactions of²²Ne+²³⁶U and²⁶Mg+²³²Th by using the kinematic separator VASSILISSA. The obtained excitation functions and the maximum production cross sections are compared with the ones for more asymmetric reactions leading to the same compound nucleus²⁵⁸102. The experimental cross sections and the results of statistical model calculations are compared and discussed.The authors express their gratitude to Prof. Yu. Ts. Oganessian for his great interest and support of this work, to Drs. E.A. Cherepanov, Yu.A. Muzychka and B.I. Pustylnik for the calculations and for the useful discussions.     

Inverse problem of mechanics in momentum space

The problem is solved of reproducing a spherically symmetric potential by means of the velocity vector hodograph in a classical mechanics approximation. A definite transcendental equation is obtained for the radial velocity dependence. Considered as an illustration is the problem of the Maxwell fish eye. A relativistic generalization is given. The algorithms constructed can be used to retrieve potentials possessing internal symmetries in the classical or quantum cases.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 46–50, January, 1985.In conclusion, I am grateful to Prof. Yu. N. Demkov for active and stimulating interest in the research.     

A family of novel DNA sequencing instruments based on single-photon detection

We have developed a family of high-performance capillary DNA sequencing instruments based on a novel multicolor fluorescent detection technology. This technology is based on two technical innovations: the multilaser excitation of fluorescence of labeled DNA fragments and the "color-blind" single-photon detection of modulated fluorescence. Our machines employ modern digital and broadband techniques that are essential for achieving superior instrument performance. We discuss the design and testing results for several versions of the automated single lane DNA sequencers, as well as our approach to scaling up to multilane instruments.     

Relationship between the morphology and combustibility of fluorinated polyamide composites

The effect that polyfluorinated alcohols immobilized on montmorillonite support exert on structuralmorphological characteristics and combustibility of polymer composites was studied with 1,1,9-trihydroperfluoro- 1-nonanol as example. The relationship between the flame resistance of this heterochain polymer and its morphology was revealed by X-ray diffraction analysis, electron microscopy, DSC, and Fourier IR spectroscopy. This relationship is associated with the reorganization of the crystal and molecular structure under the influence of fluorinated organoclay, ensuring increased degree of crystallinity and redistribution of the fractions of α- and γ-crystalline forms in the polymorphic composition of polycaprolactam, making its supramolecular structure more perfect, and favoring preparation of a fluorinated material of decreased combustibility.

     

Development of a Fourier-transform waveguide spectrometer for space applications

We describe the development of a waveguide Fourier-transform spectrometer for space-borne high-resolution sensing. A prototype device is designed to monitor the water vapor absorption band near 1,364?nm with a resolution of 0.05?nm. It has no moving parts and is based on a unique concept of arrayed interferometers implemented in silicon-on-insulator planar waveguide chip. The optical input is formed by many independent waveguides, providing a significantly increased light gathering capability (étendue) compared to single-waveguide input configurations. Enhancements of the spectrometer capabilities are achieved by stacking planar waveguide layers and by using surface gratings to couple light into the waveguides.