Influence of the Local Field and Dipole-Dipole Interactions on the Spectral Characteristics of Simple Metals and Their Nanoparticles

The effect of dipole-dipole interactions of free electrons on the spectral characteristics of simple metals and their nanoparticles is analyzed using Drude theory and the model of the Lorentz local field. It is established that accounting for the dispersion of a local field under conditions of one-dimensional (1D) confinement based on the optical constants of the bulk metal allows the determination of its spectral micro-characteristics in the frequency region of the longitudinal collective motions of the free electrons. This corresponds to the spectra of the dielectric losses of bulk plasma oscillations. A similar procedure for three-dimensional (3D) confinement produces the spectrum of dielectric losses at the frequency of localized plasma oscillations. Using a number of simple metal examples, viz., Li, Na, and K, and also Al, Be, and Mg, it is shown that the frequencies of volume and localized plasma oscillations obtained from a model of dispersion of the local field in the long-wave limit are in good agreement with the actual frequencies of the plasma oscillations of the corresponding metals and the absorption maxima of their nanoparticles with a radius of 2–20 nm. It is shown that the frequencies of the main mode of longitudinal plasma oscillations and the absorption frequency of localized plasmons are well described using the dynamic theory of crystal lattice vibrations

The 2003 eclipse of EE Cep is coming. A review of past eclipses

EE Cep is an eclipsing binary with a period of 5.6 years. The next eclipse will occur soon, in May-June 2003, and all available past eclipses were collected and briefly analysed. EE Cep shows very large changes of the shape and the depth of minima during different eclipses, however it is possible to single out some persistent features. The analysis suggests that the eclipsing body should be a long object surrounded by an extended semi-transparent envelope. As an explanation, a model of a precessing optically thick disc, inclined to the plane of the binary orbit, is invoked. The changes of its spatial orientation, which is defined by the inclination of the disc and the tilt, induced most probably by precession of the disc spin axis with a period of about 50 years, produce strange photometric behaviour of this star. The H_alpha emission, and possibly the NaI absorptions, show significant changes during several months outside of the eclipse phase.Comment: 7 pages, 7 figures, LaTeX2e, accepted by A&

Определение профиля флавоноидов в гипогликемическом сборе методом высокоэффективной жидкостной хроматографии

Objectives. Herbal hypoglycemic drugs complement the conventional approach to the treatment of type-2 diabetes based on the use of synthetic prescription drugs. However, their scientifically based application and standardization are limited due to inadequate and often outdated information on their chemical composition. Accordingly, we have developed a hypoglycemic collection (HGС) consisting of common bean pods (Phaseolus vulgaris L.), bilberry shoots (Vaccinium myrtillus L.), galega herb (Gallega officinalis L.), common knotgrass herb (Polygonum aviculare L.), burdock roots (Arctium lappa L.), and cinnamon rose hips (Rosa cinnamomea L.). According to a number of researchers, the antidiabetic properties of these herbs are largely due to the presence of polyphenolic compounds, especially flavonoids. The aim of this study was to determine the profile of flavonoids in the HGС and in its total dry extract (TDE).Methods. The study was performed by reverse-phase high-performance liquid chromatography with diode array and mass spectrometric detection.Results. Nine individual flavonol glycosides—derivatives of myricetin, quercetin, kaempferol and kaempferide—were identified in the HGC and the TDE. The main flavonol glycosides in the studied objects were robinin and kaempferol-3-glucuronide, the contents of which in the HGC were 2.09 and 2.22 mg/g, in the TDE 4.85 and 3.84 mg/g, respectively. The other flavonol glycosides were determined in the HGC and its TDE at significantly lower concentrations.Conclusions. The method developed in the study can be used to standardize HGCs and estimate their pharmacological activities.Цели. Гипогликемические препараты растительного происхождения успешно дополняют синтетические рецептурные лекарства, использующиеся в традиционном подходе к лечению сахарного диабета 2 типа. Однако научно обоснованное применение и стандартизация таких препаратов ограничены из-за неадекватной и часто устаревшей информации об их химическом составе. Нами был разработан гипогликемический сбор (ГГС), состоящий из створок фасоли обыкновенной (Phaseolus vulgaris L.), побегов черники обыкновенной (Vaccinium myrtillus L.), травы галеги лекарственной (Gallega officinalis L.), травы горца птичьего (спорыша) (Polygonum aviculare L.), корней лопуха большого (Arctium lappa L.), плодов шиповника коричного (Rosa cinnamomea L.). По мнению ряда исследователей, антидиабетические свойства вышеупомянутых растений во многом обусловлены присутствием в них полифенольных соединений, особенно флавоноидов. Цель данного исследования – определение профиля флавоноидов в ГГС и в суммарном сухом экстракте (ССЭ) на основе ГГС.Методы. Исследование проводили методом обращено-фазовой высокоэффективной жидкостной хроматографии с диодно-матричным и масс-спектрометрическим детектированием.Результаты. В ГГС и ССЭ было идентифицировано девять индивидуальных флавонолгликозидов – производных мирицетина, кверцетина, кемпферола и кемпферида. Основными флавонолгликозидами в исследуемых объектах были робинин и кемпферол-3-глюкуронид, содержание которых в ГГС составило 2.09 и 2.22 мг/г, в ССЭ – 4.85 и 3.84 мг/г, соответственно. Остальные флавонолгликозиды были обнаружены в ГГС и ССЭ в существенно более низких концентрациях.Выводы. Результаты работы могут быть использованы при стандартизации ГГС и оценке его фармакологической активности

A study of a complex of bioactive compounds in the fruits of promising blue honeysuckle (<i>Lonicera caerulea</i> L.) cultivars

Background. Blue honeysuckle (Lonicera caerulea L.) is a valuable source of bioactive compounds (BAC) of polyphenolic nature and rare for horticultural berries iridoids, which have antioxidant, anti-inflammatory, antimicrobial and other properties and are widely used in the food, medical and cosmetic industries.Materials and methods. The berries of 20 released honeysuckle cultivars of Russian, Canadian and U.S. origin, reproduced at the I.V. Michurin Federal Science Center in Tambov Province, were studied for the content of the main BAC groups using modern methods (spectrophotometry, HPLC-UV, HPLC-RID, and HPLC-DAD-MS).Results and discussion. The main BAC groups (the content and profile of anthocyanins, proanthocyanidins, flavonols and flavones, hydroxycinnamic acids (HCA), iridoids, and organic acids) as well as mono- and disaccharides were studied in detail. A comparative study of the biological value of domestic and foreign honeysuckle cultivars was carried out.Conclusions. The study resulted in identifying the most promising cultivars of honeysuckle according to the content of the main BAC groups

EXPERIMENTAL SUBSTANTIATION OF APPLICATION GEL IMPLANT «SFERO®GEL» AND FILM IMPLANT «ELASTOPOB»® AT A TRAUMA OF PERIPHERAL NERVOUS SYSTEM IN EXPERIMENT

The purpose of the present work was the experimental substantiation of application of new biodegraded materials: gel implant «Sfero®Gel» and a film membrane of «ElastoPOB»® a domestic production, in surgery of defeats of peripheral nerves. Experimental researches carried out on females of nonlinear rats, is powerful 200–250 gramme. In experience 10 animals are used, 20 operative interventions on sciatic nerves are executed. Morphological studying of the received material in 101 days after operation was carried out. At application of a membrane «ElastoPOB»® it was defined delimitin of peripheral nerves from surrounding tissue. A film membrane of «ElastoPOB»® is perspective to apply at traumas of a nervous fabric for the purpose of formation of a friable hem in a damage zone. On the basis of the received experimental data it is possible to make the conclusion about possibility and expediency of application of biodegraded materials in surgical treatment of defeats of peripheral nervous system

The Size Ellect on the Infrared Spectra of Condensed Media Under Conditions of ID, 2D and 3D Dielectric Confinement

A general expression for the dielectric loss spectrum of an absorbing composite medium was obtained from a Maxwell-Garnett general equation. This expression was simplified for the cases of one, two and three dimensional dielectric confinement in both ordered and disordered thin layers, rods (wires) and spheres of absorbing medium which are considered as mesoparticles or mesoscopic molecules. This theoretical approach was verified experimentally using high purity organic liquids with strong absorption bands in the infrared range. Three organic liquids, namely benzene, chloroform and carbon disulphide, were measured in various dielectric confinement configurations using Fourier Transform Infrared (FTIR) spectroscopy with a Grazing Angle attachment GATRTM. A significant shift of the resonant absorption band of liquid mesoparticles was observed for various dielectric confinement geometries which is in good agreement with theoretical predictions. Possible applications of this work include investigations of industrial smoke, toxic aerosols and liquid droplets

Elication of an excitation center in the depth of tissue by visualization with high-frequency electric field

Hardware and software system, which makes it possible to visualize the glow center, marker of the excitation center in tissue, in the electric field, is created. The system was tested in 14 experiments with sinoatrial nodes of cat's hearts, which's fist excitation's center is in the depth of the right auricle's myocardium, and in 30 experiments with frog's venous sinuses, which's first excitation's center is situated in the superficial layer of the sinus wall. Also observations were held with deeply situated center - in cat's tooth's pulp, which is surrounded by insulators: dentine and tooth's enamel. The ability of visualization the excitation's center was developed at localizations in different depths

Micro-Raman Mapping of 3C-SiC Thin Films Grown by Solid–Gas Phase Epitaxy on Si (111)

A series of 3C-SiC films have been grown by a novel method of solid–gas phase epitaxy and studied by Raman scattering and scanning electron microscopy (SEM). It is shown that during the epitaxial growth in an atmosphere of CO, 3C-SiC films of high crystalline quality, with a thickness of 20 nm up to few hundreds nanometers can be formed on a (111) Si wafer, with a simultaneous growth of voids in the silicon substrate under the SiC film. The presence of these voids has been confirmed by SEM and micro-Raman line-mapping experiments. A significant enhancement of the Raman signal was observed in SiC films grown above the voids, and the mechanisms responsible for this enhancement are discussed