Self-Heating Model of Spherical Aluminum Nanoparticle Oxidation

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Nanoenergetic thermites include mixtures of nanostructured Al and oxidizer particles. The main distinguishing features of these reactive systems are their significant enthalpy release and tunable rate of energy discharge, which gives rise to a wide range of combustion rates, energy release, and ignition sensitivity. In this paper, we consider rapid oxidation of a spherically symmetric aluminum particle. We use the Cabrera Mott oxidation model to describe the kinetics of oxide growth of an aluminum nanoparticle and to predict reaction temperature and oxidation time. We assume that aluminum particle of diameter 10 to 50 nm is covered by a thin oxide layer (1-4 nm) and is surrounded by abundant amount of oxygen stored by oxidizers. The particle is rapidly heated up to ignition temperature to initiate self-sustaining oxidation reaction as a result of highly exothermic reaction. We numerically investigated the oxidation model by using COMSOL multiphysics software. The software creates a mesh fitted to geometric configuration of a nanoparticle, and performs finite element method computations

Development of an advanced water filtering system based on graphene irradiated by gas cluster and highly charged ions

Effects of a heavy low energy ion bombardment of various materials are explored for the purposes of creating new materials that have advanced properties. In this study, features of the defects’ formation in the samples of graphene, graphene oxide and silicon by Ar cluster ions irradiation are given..

Development of an advanced water filtering system based on graphene irradiated by gas cluster and highly charged ions

Effects of a heavy low energy ion bombardment of various materials are explored for the purposes of creating new materials that have advanced properties. In this study, features of the defects’ formation in the samples of graphene, graphene oxide and silicon by Ar cluster ions irradiation are given..

Luminescence of sapphire single crystals irradiated with high-power ion beams

Optical absorption, photo- and cathodoluminescence of a sapphire single crystal (α-Al 2 O 3 ) exposed to pulsed nanosecond radiation with high-power ion beams C + /H + with an energy of 300 keV and energy density 0.5-1.5 J/cm 2 were first investigated in this work. It was found that under ion irradiation accompanied by heating of sapphire up to melting, the formation of F-type centers and their aggregates associated with oxygen vacancies was observed in the crystals under study. These centers have luminescence bands at 330, 410 and 500 nm which depend on the type and wavelength of the optical excitation. The appearance of a new PL emission at 435 nm, presumably associated with a complex vacancy-impurity defect, was also observed in the photoluminescence spectra. © Published under licence by IOP Publishing Ltd.The work was supported by the initiative scientific project № 16.5186.2017/8.9 of the Ministry of Education and Science of the Russian Federation. Experiments on ion irradiation of sapphire was done at the KIPT as a part of the state task

Effect of the Porosity Ran ge and its Nature on Mechanical Properties of Magnesium Alloys Mg-Al-Zn

The possibilities of porosity adjustment in alloys of the Mg-Al-Zn system obtained by melting under a layer of flux were studied. The elements that significantly increase corrosion resistance and heat resistance, and improve mechanical strength and technological characteristics were chosen as doping components. Measurements showed that the range of porosity varied between 5.9 and 14.8%, and the relationshipВ between porosity and strength of alloys was defined for the first time for this range. For an alloy with porosity of 14.8%, the percentage of open pores was 12.8% while the percentage of closed pores was 2%. Micro-hardness of alloys with the given porosity was 661 MPa after casting, 876 MPa after homogenizing annealing and 897 MPa after artificial aging. The tensile strength was 235 MPa. Analysis identified that the main cause of porosity was catching atoms of hydrogen from atmosphere by molten alloys during melting, casting and liquation. In order to reduce the percentage of porosity alloys were doped by metal manganese, liquid metal was processed by calcium and hexachloroethane, and casting form was treated by boron nitride. These manipulations resulted in reduction of samples porosity up to 5.9%, increase of tensile strength up to 240 MPa. Open porosity was 4.5%, while closed porosity was 1.4%. At the same time micro-hardness of cast samples was 867 MPa, 903 MPa after homogenization annealing and 961 MPa after artificial aging. Further reduction of porosity and increasing of magnesium alloys strength is possible with the use of inert gases or vacuum melting. Samples porosity can be increased by more than 14.8% with the help of melting in the hydrogen containing atmosphere

Применение однофотоннои эмиссионном компьютерной томографии, совмещенном с компьютерной томографией, с целью диагностики рака молочной железы

Objective. To evaluate the efficacy of single-photon emission computed tomography combined with computed tomography (SPECT-CT) in the diagnosis of breast cancer (BC).Materials and methods. We performed 44 SPECT-CT examinations in 40 women with malignant breast neoplasms.Study Results. The obtained data enabled us to calculate the characteristics of SPECT-CT in the evaluation of the primary tumor. The sensitivity, specificity, and diagnostic accuracy of the method were 88.1 %, 78.3 %, and 88.0 %, respectively. When the method was used to detect nodal and distant metastases, these characteristics were 87.3 %, 76.8 %, 86.9 % and 82.6 %, 73.1 %, 81.4 %, respectively.Conclusion. SPECT-CT is one of the most accurate methods to assess the primary tumor, lymph node involvement and distant metastases in BC. Цель исследования. Изучить эффективность применения однофотонной эмиссионной компьютерной томографии, совмещенной с компьютерной томографией (ОФЭКТ/КТ), с целью диагностики рака молочной железы (РМЖ).Материалы и методы. Проведено 44 обследования с применением ОФЭКТ/КТ 40 женщинам со злокачественными новообразованиями молочных желез.Результаты исследования. Полученные данные позволили нам рассчитать характеристики метода ОФЭКТ/КТ при оценке первичной опухоли. Чувствительность метода составила 88,1%, специфичность — 78,3%, диагностическая точность — 88,0%. Аналогичные показатели при определении метастатического поражения лимфатических узлов составили, соответственно, 87,3%, 76,8% и 86,9%, отдаленных метастазов — 82,6%, 73,1% и 81,4%.Заключение. ОФЭКТ/КТ является одним из наиболее точных методов оценки первичной опухоли, поражения лимфатических узлов и отдаленных метастазов при РМЖ.

Composite Medicine “Azisal” Based on Azithromycin and Salicylic Acid

Salicylic acid essentially is obtained under the pressure by the method of Kolbe-Schmidt. One of the biggest drawbacks of this method is the necessity of synthesizing sodium phenolate in advance which involves considerable technological difficulties: water predistillation under vacuum and also the dry sodium phenolate getting very hygroscopic. It is therefore of interest to look for more convenient alternative pathways for the synthesis of salicylic acid, excluding the use of sodium phenolate and this drawback is eliminated by using sodium and potassium salts of ethyl carbonic acid as carboxylation body. Consequently, according to the more convenient method we obtained the salicylic acid. In medicine, 1% solution of salicylic acid in 70 % alcohol called salicylic alcohol is used as an antiseptic. We investigated the antimicrobial activity of a 1% solution of salicylic acid in various concentrations of ethanol (40%, 50%, 60%, 70%, 80% and 90%) in order to determine the effect of different concentrations of ethanol on the antimicrobial activity of salicylic acid. The experiment proved that 1% solution of salicylic acid in various concentrations of ethanol (40-90%) to the appropriate strains of bacteria acts with the same activity regardless of the concentration of ethanol (40%, 50%, 60%, 70%, 80% and 90%). These actions of the acid are due to its solubility in alcohols of different concentrations and complete disintegration of salicylic acid molecules into ions. Thus, on the basis of antimicrobial research the necessity of preparation of 1% solution of salicylic acid in 40% alcohol is proved as the drug is cheaper and cost-effective to produce. The technology of the new composition of the drug “Azisal” consisting of 0.25 g azithromycin and 1.0 g salicylic acid in 60% ethanol was developed, in a similar way solution of azithromycin in different concentrations 0.25, 0.5, 0.75, 1.0% in 60% ethanol were prepared and their antimicrobial activities were defined. The comparison of their antimicrobial activity shows the effectiveness of the composite product called “Azisal”

New materials for the electromechanical and acoustoelectric transducers

The technology for creation of the polymer-microsized piezoelectriccomposite substrate is developed by employing the electric gas dis-charge plasma method. It is determined experimentally that as aresult of the nano-structurization of the volume of the polymer-pie-zoceramic composite close to the surface it is Young and piezo-modulus as well as the mechanical quality and electromechanicalcoupling coefficients and the dielectric constant has been increased,whereas, tangent losses are decreased depending on the type of thenanoparticle and its volume rate

ОПЫТ ПРИМЕНЕНИЯ БЕВАЦИЗУМАБА У БОЛЬНЫХ НЕОПЕРАБЕЛЬНЫМ КОЛОРЕКТАЛЬНЫМ РАКОМ В КИРОВСКОЙ ОБЛАСТИ

Purpose. To conduct retrospective analysis of treatment results of combined first line therapy of metastatic colorectal cancer with bevacizumab with further bevacizumab maintenance and second line treatment with or without bevacizumab use in Kirov regional clinical oncology dispensary.Materials and methods. The study was conducted in Kirov regional clinical oncology dispensary from 2008 until 2014. 35 patients treated with combined first line therapy including bevacizumab with further bevacizumab maintenance and second line treatment with or without bevacizumab were retrospectively evaluated. Overall response was evaluated using RECIST ver. 1.1 criteria. Long term outcomes – progression free and overall survival were evaluated. Treatment safety was evaluated using NCI CTCAE.Results. There were no complete remissions in second line bevacizumab treatment, partial remissions were detected for 4 (22.2 %) patients, stable disease for 14 (77.8 %). Median progression free survival in both groups was comparable 9.1 and 10.4 months respectively. Patients treated with bevacizumab in first and second lines of treatment had 8.2 months survival benefit (p > 0.05).Conclusions. Combined first line therapy of metastatic colorectal cancer with bevacizumab with further bevacizumab maintenance and second line treatment with bevacizumab improves overall survival on 8.2 months in comparison with patients who stopped bevacizumab treatment after first disease progression.Задачи. Провести ретроспективный анализ результатов комбинированной терапии 1-й линии метастатического колоректального рака (мКРР) с включением бевацизумаба с последующей поддерживающей терапией с включением бевацизумаба и терапии 2-й линии с продолжением назначения бевацизумаба или без него на базе КОГБУЗ «Кировский областной клинический онкологический диспансер».Материалы и методы. Исследование проводилось в Кировском областном клиническом онкологическом диспансере с 2008 по 2014 г. Ретроспективно оценено 35 пациентов, получавших комбинированную терапию 1-й линии мКРР с включением бевацизумаба с последующей поддерживающей терапией с включением бевацизумаба и терапию 2-й линии с продолжением назначения бевацизумаба или без него. Проводилась оценка непосредственного эффекта (общий ответ) по критериям RECIST версия 1.1. Для оценки отдаленных результатов определялась медиана общей выживаемости (ОВ) и медиана выживаемости без прогрессирования (ВБП). Оценивалась безопасность лечения с использованием NCI CTCAE.Результаты. В группе больных, продолживших терапию бевацизумабом во 2-й линии, полных ремиссий не наблюдалось, частичные ремиссии опухоли были зарегистрированы у 4 (22,2 %) пациентов, стабилизация у 14 (77,8 %). Медиана ВБП у пациентов в обеих группах была сопоставимой – 9,1 и 10,4 мес соответственно. У больных, получавших химиотерапию (ХТ) бевацизумабом в 1-й и 2-й линии, выявлено улучшение ОВ на 8,2 мес (p > 0,05).Выводы. Применение бевацизумаба в 1-й линии терапии мКРР с последующей поддерживающей терапией бевацизумабом до прогрессирования заболевания и дальнейшее применение во 2-й линии со сменой режима ХТ до 2-го прогрессирования заболевания привело к увеличению ОВ на 8,2 мес по сравнению с группой пациентов, завершивших терапию бевацизумабом при 1-м прогрессировании заболевания