On almost contact metric 1-hypersurfaces in Kählerian manifolds

We prove that an almost contact metric structure on an orientable hypersurface with type number 1 in a Kählerian manifold is necessarily cosymplectic.     

Crystal structure of 9-(5,5-dimethyl-2,4,5,6-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-phenalen-2-yl)-5,5,9-trimethyl-5,6,8,9-tetrahydrocyclopenta[<Emphasis Type="Italic">a</Emphasis>]phenalen-10(4<Emphasis Type="Italic">H</Emphasis>)-one

The structure of 9-(5,5-dimethyl-2,4,5,6-tetrahydro-1H-phenalen-2-yl)-5,5,9-trimethyl-5,6,8,9-tetrahydrocyclopenta[а]phenalen-10(4H)-one was determined by X-ray crystallography. The intermolecular interaction energies were calculated by the atom-atomic approach for the crystal structure. The character of the crystal structure and the structural subclass were established.     

Almost contact metric hypersurfaces with type number 0 or 1 in nearly-Kählerian manifolds

It is proved that for an almost contact metric hypersurface in a nearly-Kählerian manifold the condition that the type number is equal to 1 or 0 is not only necessary but also sufficient for this almost contact metric structure be weakly cosymplectic.     

Critical Molecular Coordination Numbers in the Structural Class P21/c,Z = 4(1)

Moscow University Chemistry Bulletin - The network of intermolecular contacts in an organic crystal contains a finite set of strong contacts sufficient to form a network. These contacts form a...     

Proton redundancy in planar aqueous networks (H<Subscript>2</Subscript>O)<Subscript>∞</Subscript>

It has been shown by numerical experiments that, at any finite set of the type {i ₁, i ₂, ..., im} with acceptable sizes of an i-angle aqueous cycle of the (H₂O)_∞ planar network, the most probable mean size of the cycle is the arithmetical mean of the above set. The maximally degenerate proton redundancy values of the aqueous network have been obtained. Supposing that proton redundancy values are rational, a range of the most probable values of the mean size of an aqueous cycle in the network has been deduced.     

Dependence of pharmacokinetic properties of 1,4-dihydropyridine calcium antagonists on agglomeration in crystals

With the aim of validating the hypothesis that the pharmacokinetic properties of drugs depend on molecular agglomeration, crystal-chemical analysis was performed for the following representatives of 1,4-dihydropyridine calcium antagonists: nifedipine, felodipine, and nitrendipine. These compounds belong to the structural class P2₁/c, Z = 4(1). The energy of intermolecular interactions was calculated with the use of the CCA program designed for the conventional crystal-chemical analysis. The structural subclasses for the compounds in question were determined. On the basis of the published data, the relationship between the pharmacokinetic properties of these compounds and molecular agglomeration was revealed.     

Multivariate analysis of melting points for homologous series C x H2x − 1NO (x = 3−6)

A multivariate analysis of the empirical structure data for isomeric homologues using principal-component analysis has been carried out, and the correlation with experimental melting points has been shown. Based on the data on the CSD structure, we discuss the impact of molecular H-aggregation.     

On almost contact metric hypersurfaces with type number 1 in 6-dimensional Kähler submanifolds of the Cayley algebra

We prove that the condition for the type number of an almost contact metric surface in a six-dimensional Kähler submanifold of the Cayley algebra to be 0 or 1 is not only necessary but also sufficient condition for the almost contact metric structure to be cosymplectic.     

Pseudosymmetry in the crystal structure of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine

Within the framework of a detailed crystallochemical analysis a comparison of the structures of symmetrically independent molecules was performed and the energy of intermolecular interaction was calculated for a triclinic bisystem crystal, 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine. Pseudosymmetrical operations were detected and identified. The presence of highly efficient layers with pseudomonoclinic symmetry was disclosed in this structure.