Nilpotent Steiner loops of class 2

We describe Steiner loops of nilpotency class 2 and establish the classification of finite 3-generated nilpotent Steiner loops of nilpotency class 2.     

Synthesis and Properties of N,N′-Disubstituted Ureas and Their Isosteric Analogs Containing Polycyclic Fragments: II. N-(4-Oxoadamantan-1-yl)-N′-[fluoro(chloro)phenyl]ureas

Russian Journal of Organic Chemistry - A series of N-(4-oxoadamantan-1-yl)-N′-[fluoro(chloro)phenyl]ureas have been synthesized in 27–73% yields by reaction of...     

Synthesis of Bicyclic Isocyanates and Bioisosteric 1,3-Disubstituted Ureas as Soluble Epoxide Hydrolase Inhibitors

Russian Journal of Organic Chemistry - (1S)-1-Isocyanato-4,7,7-trimethyl-2-oxabicyclo[2.2.1]heptan-3-one and 2-isocyanatobicyclo[2.2.1]-hept-5-ene were prepared by the Curtius rearragement reaction...     

Microwave synthesis of hydroxyapatite and physicochemical study of its properties

Method for microwave liquid-phase synthesis of hydroxyapatite samples was developed. The composition of the synthesis products obtained and natural hydroxyapatite was studied by X-ray phase and X-ray fluorescence microanalysis. IR spectra were measured and the dispersity of hydroxyapatite powders obtained, their solubility in water at 20°C, and structural parameters were determined in comparison with natural hydroxyapatite and that produced by the common (“classical”) liquid-phase technique. The microwave-synthesized hydroxyapatite compares well in its properties with the biological and “classical” hydroxyapatites.     

Levi and Malcev Theorems for Finite-Dimensional Algebras from the Variety Defined by the Identities x2 =J(x,y, zu) =0

We study the variety of binary Lie algebras defined by the identities x2 =J(x,y,zu) =0,where J(a,b,c) denotes the Jacobian of a,b,c.Building on previous work by Carrillo,Rasskazova,Sabinina and Grishkov,in the present article it is shown that the Levi and Malcev theorems hold for this variety of algebras.     

Mechanisms of sibilant noise formation observed during forced exhalation of a healthy person

Wheezes of the forced exhalation (FEW) are important for the diagnostics of bronchial obstruction, however, mechanisms of FEW noise formation have not been clearly identified. The objective of the study is statistical modeling of mechanisms of FEW noise formation in the selected subset of health volunteers. FEW were identified by experts with the use of the spectrogram. The frequencies of FEW with maximal amplitudes were determined in four time fractions. In the assumption of air incompressibility for Weibel morphometry of the bronchial tree considering a decreased section of the respiratory tract at the forced exhalation, the average values of proportionality coefficients between the correlations of the linear velocity of air flow and the average diameters of the respiratory tract, and the maximal frequencies of FEW were calculated. Obtained values of the coefficients have been compared with predictable empirical models     

Hyperbolic Kac-Moody algebras of rank 2

We describe the structure of a hyperbolic Kac-Moody algebra of rank 2 treated as a module over a root subalgebra which is isomorphic to a simple 3-dimensional Lie algebra and is associated with an imaginary root.Translated fromAlgebra i Logika, Vol. 33, No. 3, pp. 286–300, May–June, 1994.     

Synthesis and Properties of N,N′-Disubstituted Ureas and Their Isosteric Analogs Containing Polycyclic Fragments: XI. 1-[(Adamantan-1 yl)alkyl]-3-arylselenoureas

Russian Journal of Organic Chemistry - A series of N,N′-disubstituted selenoureas containing an adamantane fragment have been synthesized in 23–75% yields. Procedures for the isolation...