Gas chromatography of organometallic compounds of group IVB with heteroelement-heteroelement bonds

Russian Chemical Bulletin -     

Theory of stabilizing thermally stable polymers

It has been discovered that chemical compounds generated in some polymeric samples or articles and possessing high activity in the reactions with oxygen and free radicals as well as yielding inert products in the above reactions may stabilize the polymeric materials by inhibiting oxidative (and even thermal) degradation. The phenomenon described has both theoretical and experimental evidence.     

Dependence of laser radiation intensity on the elastic deformation of a revolving optical disk with a reflective coating

The physical mechanism of alteration of intensity of linearly polarized monochromatic electromagnetic radiation with λ = 630 nm in a revolving dielectric disk with a mirror coating is examined. The effect is induced by elastic deformation due to the revolution and by thermoelastic deformation of the optically transparent disk. These deformations result in birefringence, the polarization plane rotation, and a 30–40% change in the intensity of reflected radiation.     

Erratum to: Optical Gain of 1550-nm Range Multiple-Quantum-Well Heterostructures and Limiting Modulation Frequencies of Vertical-Cavity Surface-Emitting Lasers Based on Them

Optics and Spectroscopy - The name of the seventh author should read L. Ya. Karachinsky.     

Comparative Genomics and Evolution of Molybdenum Utilization

The trace element molybdenum (Mo) is the catalytic component of important enzymes involved in global nitrogen, sulfur, and carbon metabolism in both prokaryotes and eukaryotes. With the exception of nitrogenase, Mo is complexed by a pterin compound thus forming the biologically active molybdenum cofactor (Moco) at the catalytic sites of molybdoenzymes. The physiological roles and biochemical functions of many molybdoenzymes have been characterized. However, our understanding of the occurrence and evolution of Mo utilization is limited. This article focuses on recent advances in comparative genomics of Mo utilization in the three domains of life. We begin with a brief introduction of Mo transport systems, the Moco biosynthesis pathway, the role of posttranslational modifications, and enzymes that utilize Mo. Then, we proceed to recent computational and comparative genomics studies of Mo utilization, including a discussion on novel Moco-binding proteins that contain the C-terminal domain of the Moco sulfurase and that are suggested to represent a new family of molybdoenzymes. As most molybdoenzymes need additional cofactors for their catalytic activity, we also discuss interactions between Mo metabolism and other trace elements and finish with an analysis of factors that may influence evolution of Mo utilization.     

Syntheses and reactions of triethylgermyllithium,-sodium, -potassium, -rubidium and -caesium in weak solvating solvents

Germylmetallic compounds, Et₃GeM, where M = Li, Na, K, Rb and Cs, have been prepared in high yield in n-hexane or benzene by the reaction of bis(triethylgermyl)mercury with the appropriate alkali metal. Reactions of these compounds with trimethylchlorosilane afforded the coupled product Et₃GeSiMe₃. The interaction of Et₃GeM with benzophenone, acetophenone and phenylacetylene has also been examined. The course of these reactions (i.e. the composition and the yields of the various products) is strongly dependent on the solvating abitity of the solvent and the nature of the alkali metal M.     

Electrical transport and magnetic ordering in R 2Ti3Ge4 (R=Dy, Ho and Er) compounds

New R ₂Ti₃Ge₄ (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize in the parent, Sm₅Ge₄-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series. The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects.     

Development of a toolkit for early precision immunochromatographic diagnosis

A device is developed for automated immunochromatographic assay, designed for one-time tests at the place of occurrence of a disease. The device comprises a turntable platform for up to five strips placed simultaneously, a unit for sample collection and microdosing to a test strip, a detection unit, and a microprocessor control system. A manual, semiautomatic, or automatic operation mode may be selected. Colloidal quantum dots with a luminescence peak from the visible to near-infrared spectral region (600–800 nm) are used as fluorescent labels. A UV-LED or a laser at 365–480 nm can be used as an excitation system; the detection device is a spectrometer with an operation range of 500–800 nm, based on a CCD series of TCD1304DG sensors (Toshiba). RFID tags of samples can re read and the analysis results can be sent to an external computer. The device is made in a plastic case for carrying.