Voronezh State University

About: Voronezh State University is a education organization based out in Voronezh, Russia. It is known for research contribution in the topics: Silicon & Boundary value problem. The organization has 5166 authors who have published 6097 publications receiving 31680 citations. The organization is also known as: VSU & Voronezh University.

Small parameter perturbations of nonlinear periodic systems

Abstract: In this paper we consider a class of nonlinear periodic differential systems perturbed by two nonlinear periodic terms with multiplicative different powers of a small parameter ? > 0 For such a class of systems we provide conditions that guarantee the existence of periodic solutions of given period T > 0 These conditions are expressed in terms of the behaviour on the boundary of an open bounded set U of of the solutions of suitably defined linearized systems The approach is based on the classical theory of the topological degree for compact vector fields An application to the existence of periodic solutions to the van der Pol equation is also presented

Organic–inorganic nanostructures for luminescent indication in the near-infrared range

Abstract: Amplifying and quenching of IR luminescence of colloidal Ag2S quantum dots were revealed to take place when they couple to organic dye molecules of 3,3′-di-(γ-sulfopropyl)-9-ethyl-4,5,4′,5′-dibenzothiacarbocyanine betaine and erytrosine pyridinium salts, respectively. The observed effects are explained as due to the formation of organic–inorganic heterostructures with different mutual arrangement of electronic states of the dyes and the quantum dots.

Embeddings of Rearrangement Invariant Spaces that are not Strictly Singular

Abstract: We give partial answers to the following conjecture: the natural embedding of a rearrangement invariant space E into L 1([0,1]) is strictly singular if and only if G does not embed into E continuously, where G is the closure of the simple functions in the Orlicz space L Φ with Φ(x) = exp(x2)-1.

A Molecular Method for the Identification of Honey Bee Subspecies Used by Beekeepers in Russia

Abstract: Apis mellifera L. includes several recognized subspecies that differ in their biological properties and agricultural characteristics. Distinguishing between honey bee subspecies is complicated. We analyzed the Folmer region of the COX1 gene in honey bee subspecies cultivated at bee farms in Russia and identified subspecies-specific SNPs. DNA analysis revealed two clearly distinct haplogroups in A. mellifera mellifera. The first one was characterized by multiple cytosine-thymine (thymine–cytosine) transitions, one adenine-guanine substitution, and one thymine–adenine substitution. The nucleotide sequence of the second haplogroup coincided with sequences from other subspecies, except the unique C/A SNP at position 421 of the 658-bp Folmer region. A. mellifera carnica and A. mellifera carpatica could be distinguished from A. mellifera mellifera and A. mellifera caucasica by the presence of the A/G SNP at position 99 of the 658-bp Folmer region. The G/A SNP at position 448 was typical for A. mellifera carnica. A. mellifera caucasica COX1 sequence lacked all the above-mentioned sites. We developed a procedure for rapid identification of honey bee subspecies by PCR with restriction fragment length polymorphism (RFLP) using mutagenic primers. The developed molecular method for honey bee subspecies identification is fast and inexpensive.

Synthesis and Anticoagulant Activity of New Ethylidene and Spiro Derivatives of Pyrrolo[3,2,1-ij]quinolin-2-ones

Abstract: The reaction of pyrrolo[3,2,1-ij]quinoline-1,2-diones with methyl (het)aryl ketones gave the corresponding 1-(het)arylmethylidenepyrroloquinolin-2-ones, and 1,3-dipolar cycloaddition of the latter to azomethine ylide generated from sarcosine and paraformaldehyde afforded 4-acyl-1,4′,4′,6′-tetramethylspiro[pyrrolidine-3,1′-pyrrolo[3,2,1-ij]quinolin]-2′(4′H)-ones. The synthesized compounds were evaluated for inhibitory activity against blood coagulation factors Xa and XIa.