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91.
92.
S. S. Muradova T. Yu. Yusupov I. M. Khalilov A. G. Guzalova M. M. Muradov 《Chemistry of Natural Compounds》2001,37(6):559-561
The buoyant density of DNA from various local strains of mung-bean nodule bacteria (Bradyrhizobium sp.) was determined by ultracentrifugation in an equilibrium CsCl gradient. The number of GC base pairs (61.1-62.7% mol %) and DNA melting point (94.3-95.0°C) were calculated from the buoyant density. DNA preparations purified by ultracentrifugation in a CsCl gradient by electrophoresis show a bimodal distribution. The DNA composition varies little (1.6 mol %). The electrophoretic distribution of local and Type-strain mung-bean nodule bacteria are identical. This proves that they belong to a single taxonomic group. 相似文献
93.
In the one-loop approximation of quantum electrodynamics, we study the Faraday rotation effect in the propagation of a weak linearly polarized wave through the field of a strong plane electromagnetic wave and also processes induced by a strong wave: the emission of a photon whose energy is an integer multiple of the strong-wave quantum and photon absorption with the emission of several photons identical (coherent) to the strong-wave quanta. The induced processes should occur in a vacuum in a superposition of external fields, namely, the field of a strong plane electromagnetic wave and a static spatially inhomogeneous electromagnetic field. We show that the induced photon emission in the field of a strong electromagnetic wave with circular polarization and in a static inhomogeneous field is equivalent to the merging of two strong-wave quanta with the production of one photon and that the induced photon absorption in the same combination of fields is equivalent to the decay (splitting) of a photon into two photons completely identical to the strong-wave quanta. All these effects are induced by the phenomenon of the vacuum polarization by a strong external time-dependent electromagnetic field. The probabilities of the induced processes are nontrivial nonlinear functions of the squared strength of the time-dependent field also depending on other parameters. 相似文献
94.
A model of a degenerate gas consisting of neutrons that are in chemical equilibrium with degenerate protons and electrons in a stationary and homogeneous superstrong magnetic field is used to describe the state of the matter in central regions of strongly magnetized neutron stars. Expressions for thermodynamic quantities (such as energy density, particle density, pressure, and magnetization) characterizing a degenerate gas of neutrons, protons, and electrons are obtained. In these expressions, the contributions determined by the interaction between anomalous magnetic moments of fermions and the magnetic field are taken into account. Macroscopic effects that may occur in strongly magnetized neutron stars are discussed. We show that all thermodynamic quantities characterizing electrically charged fermions in a strong magnetic field are subject to nonperiodic oscillations caused by the interaction of the anomalous magnetic moments of protons and electrons with the magnetic field. We also show that if the nucleon density and the electron density exceed threshold values that are relatively small and depend on the magnetic field strength, all fermions are fully polarized with respect to the spin. The full spin polarization effect in neutrons is caused by the interaction between the anomalous magnetic moment and the magnetic field. The obtained results may prove useful in understanding processes that occur in the nucleus of a neutron star with a magnetic field frozen into the star. 相似文献
95.
G. A. Tolstikov L. A. Baltina L. M. Khalilov L. V. Spirikhin V. R. Sultanmuratova Yu. I. Murinov 《Chemistry of Heterocyclic Compounds》1991,27(6):623-626
3-(-D-Ribofuranosyl)-5-hydroxy-6-methyluracil was synthesized by the silyl method in the presence of SnCl4 using 1-O-acetyl-2,3,5-tri-O-benzoyl--D-ribofuranose as the carbohydrate component. The structures of the glycosides were confirmed by spectral methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 794–797, June, 1991. 相似文献
96.
A. G. Mustafin I. N. Khalilov I. B. Abdakhmanov G. A. Tolstikov 《Chemistry of Natural Compounds》1989,25(6):693-695
A convenient route is described for the preparation of 1,4-dimethylcarbazole — the key compound in the synthesis of the antitumoral alkaloid ellipticine. The interaction of 2,5-xylidine with 3-chlorocyclohexene led to N-(cyclohex-2-enyl)-2,5-xylidine (I), the two-hour heating of which at 140–150°C gave the product of an amino-Claisen rearrangement, 6-(cyclohex-2-enyl)-2,5-xylidine (II) with a yield of 82%. The intramolecular cyclization of compound (II) in polyphosphoric acid (130–140°C, 5 h) led to 5,6,7,8,12,13-hexahydro-1,4-dimethylcarbazole (III) in a yield of 75%. The dehydrogenation of substance (III) by boiling in trimethylbenzene in the presence of Pd/C gave 1,4-dimethylcarbazole (IV) with a yield of 87%. The conditions for performing the reactions and the physicochemical constants of the compounds obtained are given. 相似文献
97.
In the weakly relativistic limit, an expression is obtained for the damping of quasistationary energy levels in Schwarzschild and Kerr fields due to capture by a collapsar. The strength of the damping in the Schwarzschild field decreases strongly with increasing angular momentum of the particle. If the condition < mH is satisfied in the case of a rotating black hole, the damping can be replaced by excitation. A particle production process (Hawking process) is considered that leads to the accumulation of particles on quasistationary levels near the black hole. Dynamical equilibrium can be established in the system between the processes of production and capture of particles by the black hole.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, 109–114, September, 1978. 相似文献
98.
L. M. Khalilov O. V. Shitikova R. I. Khusnutdinov U. M. Dzhemilev 《Russian Chemical Bulletin》1998,47(12):2463-2464
Comparison of experimental and calculated chemical shifts of carbon atoms in13C NMR spectra of two isomeric dodecacyclo[14.9.1.14,13.17,10.02,15.03,14.05,12.06,11.017,25.018,24.019,21. 020,24]-octacos-8-enes, bicyclo[2.2.1]heptadiene tetramers, confirmed theirexo-trans-exo-trans-exo-endo-andexo-trans-exo-trans-exo-exo-configurations.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2545–2547, December, 1998. 相似文献
99.
L. M. Khalilov E. V. Vasil'eva A. A. Fatykhov G. A. Tolstikov 《Chemistry of Natural Compounds》1991,27(3):313-317
An assignment of1H and13C NMR signals has been made by the methods of homonuclear two-dimensional spectroscopy, HH COSY (45°), and heteronuclear correlation spectroscopy, CH HET CORR. It has been shown that the range of diastereomeric effects in the13C NMR spectra substantially exceeds the effects due to solvents, in contrast to the proton spectra in which these ranges overlap.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 363–368, May–June, 1991. 相似文献
100.
V. N. Odinokov I. V. Galyautdinov A. A. Fatykhov L. M. Khalilov 《Russian Chemical Bulletin》2000,49(11):1923-1924
A new phytoecdysteroid,viz, 2-deoxy-3-epi-4β, 20-dihydroxycedysone ((20R,22R)-3α,4β 14α,20,22,25-hexahydroxy-5β-cholest-7-en-6-one), named coronatasteronc, was isolated fromSerratula coronata and identified by NMR spectroscopy.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1955, November, 2000. 相似文献