THE DEPENDENCE OF THE CHAIN BRANCHING DEGREE ON MOLECULAR WEIGHT: FRACTAL ANALYSIS

The fractal analysis methodology allows the clear structural identification of both chemical and physical factors controlling a chain branching degree. The effective number of branching centers per one macromolecule m is controlled by four factors: polymer molecular weight, MW, maximal “chemical” density of reactive centers, cch, dimension of non-screening surface of macromolecular coil, du, and its fractal dimension, D. The presented research allows the determination of the critical value, Dcr = 1.10, the lower of which branching degree is equal to zero (i.e., branching does not occur

Comprehensive patterns of comorbidity: copd and depression

Introduction: Data on the prevalence of psychopathological disorders in the exacerbation of chronic obstructive pulmonary disease (COPD) are very heterogeneous. COPD and depression have common predisposing factors. The aim: The aim of the research is to conduct a comprehensive assessment of the e»ect of paroxetine on the level of depressive disorders in the exacerbation of severe degree COPD in women. Materials and methods: The study included patients with severe degree COPD and depressive disorder. A step-by-step test, dynamometry of muscular strength of muscle groups and calculation of the percent ratio of muscular strength to mass were performed for all patients, and the strength of the respiratory muscles was measured. To assess the level of depression, the HADS questionnaire and the CES-D self-questionnaire were used. Assessment of the severity of the patient’s condition was conducted according to the Hospital Alert and Depression Scale (HADS). Results: In exacerbation of severe COPD, the level of depression in patients correlates with the severity of the main criteria: FEV1, the 6-minute step test distance, oxygen saturation after the 6-minute step test, expiratory pressure in the oral cavity. Conclusions: Upon the synchronization of the standard therapy, the level of depression in patients with exacerbation of severe COPD e»ectively decreases. Paroxetine is a valid choice in the comprehensive treatment of COPD. According to the data of evidence-based medicine, the medication demonstrates high eÈciency and favorable safety pro le, without exerting a negative e»ect on COPD, which is of key signi cance in the combined pathology treatment

ВЛИЯНИЕ ПРИРОДЫ И СОДЕРЖАНИЯ НАПОЛНИТЕЛЕЙ НА СВОЙСТВА КОМПОЗИТОВ НА ОСНОВЕ ФЕНИЛОНА

 Physico-mechanical and tribotechnical properties of materials obtained on the basis of phenilon С-2 thermoplastic modified with thermally expanded graphite and synthesized by cobalt epoxy-silicate have been investigated. The optimum composite content and maintenance modes have been stated. The combined application of compounds result in their mutual activation and synergetic effect allowing to vary widely the operational properties of the material was shown. Исследованы физико-механические и триботехнические свойства материалов, полученных на основе термопласта фенилон С-2, модифицированного терморасширенным графитом и синтезированным эпоксисиликатом кобальта. Установлены оптимальные состав композита и режимы эксплуатации. Показано, что совместное использование наполнителей приводит к их взаимному активированию и синергическому эффекту, позволяющему широко варьировать эксплуатационные свойства материала.

THE DEPENDENCE OF THE CHAIN BRANCHING DEGREE ON MOLECULAR WEIGHT:

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ENVIRONMENTAL AND ECONOMIC PROSPECTS FOR USAGE OF PULTRUDED COMPOSITE SHEET PILES

The article focuses on the description of pultruded composite sheet piles. The article covers the production technology, advantages over other traditional materials, as well as environmental and economic prospects for expanding of the usage of composite sheet piling

Paramagnetic Properties of Fullerene-Derived Nanomaterials and Their Polymer Composites: Drastic Pumping Out Effect

Abstract The evolution of paramagnetic properties of the fullerene soot (FS), fullerene black (FB), and their polymer composites Phenylon C-2/FS, FB has been studied using the electron paramagnetic resonance (EPR) method. For the first time, a drastic growth of the EPR signals in the FB, FS, and composite samples was observed under pumping out at temperatures T = 20 ÷ 300 °C, which is attributed to the interaction between carbon defects and adsorbed gas molecules, mainly oxygen. It is shown that the ensemble of paramagnetic centers in the FB, FS, and the composite is heterogeneous. This ensemble consists of three spin subsystems 1, 2, and 3 related with different structural elements. The subsystems give three corresponding contributions, L 1, L 2 and L 3, into the overall contour of the EPR signal. The most intensive and broad signal L 3 is caused by 2D electrons from the surface of carbon flakes. Theoretical calculations of the L 3 signal line shape were carried out, and the decay rate of the integral intensity has been obtained for each component L 1, L 2, and L 3 after the contact of the sample with the ambient air. The signal decay process in the bulk composite samples is much slower due to their low gas permeability at room temperature (RT)