Synthesis of a new cyclic analogue of luliberin

A new cyclic analogue of luliberin possessing the capacity for stimulating ovulation in sexually mature and infantile rats and also exhibiting a pronounced prolongation of its influence on a number of behavioral reactions of animals has been synthesized.     

Simulation of the tomographic reconstruction of thermoacoustic sources: Iteration-correlation methods

Schemes for improving the resolution of thermal tomographs using multielement receiving arrays are considered. Algorithms for processing the space-time correlation information are developed on the basis of the generalization of the high-resolution spectral analysis techniques in application to the problems of medical acoustic thermotomography in narrow-band and wide-band modes of operation. Special attention is given to Capon-type algorithms, which allow an increase in the spatial resolution of the fine structure of the power density distribution of thermoacoustic radiation sources.     

A new method of synthesizing mesoionic 1,2,4-triazole-3-thiones and their spectra

Mesoionic 1,2,4-triazole-3-thiones have been synthesized by the reaction of 1-acyl-1-arylhydrazines and 1-acyl-1-alkylhydrazines with isothiocyanates in the presence of triethylamine. The structure of the compounds obtained has been confirmed by a study of their UV, IR, PMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1136–1142, August, 1973.     

Amplified luminescence and threshold current temperature dependencies of ZnSe and GaN laser diodes

Using a transfer equation approach, it is shown that the cavity-trapped amplified luminescence (AL) flux densities S integrated over the frequency and cavity length at the threshold of ZnSe, zinc-blende and wurtzite GaN laser diodes (LDs) with stripe-geometry bulk active layers reach (3.5–9)×10⁴ MW/m² within the temperature range 200–400 K. At these values of S, the nonlinear optical effects induced by AL can be observed. The AL induced recombination can enhance the threshold current density of the short wavelength LDs by two or even three times. Received: 7 January 2002 / Revised version: 11 April 2002 / Published online: 8 August 2002     

Contrast agents for magnetic resonance imaging based on dendronized <Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone polymers

In order to prepare polymeric contrast agents, various ways of modification of N-vinylpyrrolidone copolymers with vinylamine or acrolein with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid derivatives were investigated.     

Oligonucleotide cross-linking with copper ions. Spectral and quantum chemical study

Copper(II) complexes with synthetic oligonucleotides consisting of repeating adenine–thymine and guanine–cytosine complementary base pairs have been studied by UV spectroscopy and simulated by DFT quantum chemical calculations at the B3LYP/6-311G++(d,p) level of theory with inclusion of solvation (hydration) effects. The obtained data suggest selective interaction of copper(II) ions with guanine–cytosine complementary pairs, followed by DNA cross-linking at those sites.