Определение возможности применения неметаллических контрольных образцов для оценки работоспособности дефектоскопических материалов и оценки чувствительности капиллярного контроля

INTRODUCTION. Liquid penetrant testing (PT) is one of the most widely used non-destructive testing methods for detecting surface discontinuities in nonporous solid materials. This method has shown good results when looking for defects in details made of any nonporous materials including glass, ceramics, plastic, magnetic or nonmagnetic metals or alloys. Penetrant materials and check samples are the main tools for PT. The samples are used to estimate the performance of penetrant materials and to evaluate the sensitivity of the testing technology. AIM OF THE PAPER. The paper aims to evaluate the discontinuity parameters, such as cracks, in non-metal samples to determine the feasibility of using these samples to assess the sensitivity of the testing technology. METHODS. Discontinuity parameters in non-metallic check samples were determined using a microscope, and then the data was statistically processed in accordance with GOST 8.736-2011"Multiple direct measurements. Methods of measurement results processing. Main principles". RESULTS. The conducted study has showed that samples made of non-metallic material can be used to estimate the performance of penetrant families, as well as to assess penetrant testing sensitivity since the cracks in samples are virtually straight.Введение. Капиллярный метод неразрушающего контроля является одним из наиболее широко используемых методов для выявления поверхностных несплошностей в твердых непористых материалах. Данный метод хорошо зарекомендовал себя при поиске дефектов в деталях из любых непористых материалов, в том числе стекла, керамики, пластмассы, магнитных и немагнитных металлах и сплавах. Дефектоскопические материалы и контрольные образцы являются основными средствами капиллярного контроля. Образцы служат для определения работоспособности дефектоскопических материалов и оценки чувствительности технологии контроля. Цель работы - оценка влияния параметров несплошностей типа трещин в образцах из неметалла для определения возможности применения таких образцов для оценки чувствительности технологии контроля. Методы исследования. Параметры несплошностей в неметаллических контрольных образцах определяли с помощью микроскопа, затем полученные данные подвергали статистической обработке в соответствии с ГОСТ 8.736-2011 «Измерения прямые многократные. Методы обработки результатов измерений. Основные положения». Результаты. По результатам исследования выявлено, что образцы из неметаллического материала пригодны для определения работоспособности наборов дефектоскопических материалов, а также возможности применения данных образцов для оценки чувствительности капиллярного контроля, так как трещины в образцах получаются практически прямолинейными

Моделювання та дослідження магнітоелектричного перетворювача для гідро- та пневмоприводів

Purpose. Presentation of the results of modeling and practical implementation of a magnetoelectric converter for hydraulics and pneumatics systems of the aerospace industry. Methodology. Calculations of three-dimensional magnetic fields are carried out with the Finite Element Method by JMAG program. The solution of the differential equations connecting the input voltage, current, magnetic flux and torque is performed by numerical integration. Results. As a result of calculations, the converter configuration was obtained. Tests of the prototype model of the converter confirmed the principle workability of the adopted design and design solutions in its development. Practical value. Tests of the converter prototype sample confirmed the fundamental performance of the adopted design and constructive solutions.Наведено результати моделювання та практичної реалізації магнітоелектричного перетворювача для гідро- та пневмоприводів аерокосмічної галузі. На основі серії проектних розрахунків при різноманітній конфігурації магнітної системи перетворювача обрано варіант з чотирма зубцями на полюсі статору і отримані його основні характеристики. Результати розрахунків зіставлені з результатами експерименту на макетному зразку магнітоелектричного перетворювача

Определение содержания серы в топливе методом инверсионной вольтамперометрии

The paper describes the developed methodology for sulphur determination with the help of  an inversion voltammetry. The method includes an electrode regeneration at 500 mV (in reference to silver chloride electrode) within 20 sec, sulphur concentration at 100 mV, registration of cathode current-potential curve with 200 mV/sec and within potential interval from 100 up to 400 mV.Разработана методика определения серы методом инверсионной вольтамперометрии, включающая регенерацию электрода при 500 мВ (относительно хлоридсеребряного электрода) в течение 20 с, концентрирование серы при 100 мВ, регистрацию катодной вольт-амперной кривой с разверткой потенциала 200 мВ/с в интервале потенциалов от 100 до 400 мВ

Pixelated full-colour small molecule semiconductor devices towards artificial retinas

Opto-stimulation of semiconductor-biointerfaces provides efficient pathways towards eliciting neural activity through selective spectral excitation. In visual prosthesis, tri-colour stimulation capability is the key to restoring full-colour vision. Here we report on investigation of organic photoactive π-conjugated donor–acceptor small molecules based on triphenylamine whose absorption spectra are similar to those of the photoreceptors of the human eye. Photoactive device fabrication and characterisation towards full colour, pixelated retinal prosthesis based on inkjet printing of these molecules is demonstrated, with round pixels reaching 25 microns in diameter. Photo-response is studied via interfacing with biological electrolyte solution and using long-pulse, narrow-band excitation. Both photo-voltage and photo-current responses in the devices with a ZnO hole-blocking interlayer show clear signatures of capacitive charging at the electrolyte/device interface, also demonstrating spectral selectivity comparable to that of human eye’ cones and rods

Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure

Expression of Foxm1 Transcription Factor in Cardiomyocytes Is Required for Myocardial Development

Forkhead Box M1 (Foxm1) is a transcription factor essential for organ morphogenesis and development of various cancers. Although complete deletion of Foxm1 in Foxm1−/− mice caused embryonic lethality due to severe abnormalities in multiple organ systems, requirements for Foxm1 in cardiomyocytes remain to be determined. This study was designed to elucidate the cardiomyocyte-autonomous role of Foxm1 signaling in heart development. We generated a new mouse model in which Foxm1 was specifically deleted from cardiomyocytes (Nkx2.5-Cre/Foxm1fl/f mice). Deletion of Foxm1 from cardiomyocytes was sufficient to disrupt heart morphogenesis and induce embryonic lethality in late gestation. Nkx2.5-Cre/Foxm1fl/fl hearts were dilated with thinning of the ventricular walls and interventricular septum, as well as disorganization of the myocardium which culminated in cardiac fibrosis and decreased capillary density. Cardiomyocyte proliferation was diminished in Nkx2.5-Cre/Foxm1fl/fl hearts owing to altered expression of multiple cell cycle regulatory genes, such as Cdc25B, Cyclin B1, Plk-1, nMyc and p21cip1. In addition, Foxm1 deficient hearts displayed reduced expression of CaMKIIδ, Hey2 and myocardin, which are critical mediators of cardiac function and myocardial growth. Our results indicate that Foxm1 expression in cardiomyocytes is critical for proper heart development and required for cardiomyocyte proliferation and myocardial growth

β-Catenin Loss in Hepatocytes Promotes Hepatocellular Cancer after Diethylnitrosamine and Phenobarbital Administration to Mice

Hepatocellular Carcinoma (HCC) is the fifth most common cancer worldwide. β-Catenin, the central orchestrator of the canonical Wnt pathway and a known oncogene is paramount in HCC pathogenesis. Administration of phenobarbital (PB) containing water (0.05% w/v) as tumor promoter following initial injected intraperitoneal (IP) diethylnitrosamine (DEN) injection (5 µg/gm body weight) as a tumor inducer is commonly used model to study HCC in mice. Herein, nine fifteen-day male β-catenin knockout mice (KO) and fifteen wild-type littermate controls (WT) underwent DEN/PB treatment and were examined for hepatic tumorigenesis at eight months. Paradoxically, a significantly higher tumor burden was observed in KO (p<0.05). Tumors in KO were β-catenin and glutamine synthetase negative and HGF/Met, EGFR & IGFR signaling was unremarkable. A significant increase in PDGFRα and its ligand PDGF-CC leading to increased phosphotyrosine-720-PDGFRα was observed in tumor-bearing KO mice (p<0.05). Simultaneously, these livers displayed increased cell death, stellate cell activation, hepatic fibrosis and cell proliferation. Further, PDGF-CC significantly induced hepatoma cell proliferation especially following β-catenin suppression. Our studies also demonstrate that the utilized DEN/PB protocol in the WT C57BL/6 mice did not select for β-catenin gene mutations during hepatocarcinogenesis. Thus, DEN/PB enhanced HCC in mice lacking β-catenin in the liver may be due to their ineptness at regulating cell survival, leading to enhanced fibrosis and regeneration through PDGFRα activation. β-Catenin downregulation also made hepatoma cells more sensitive to receptor tyrosine kinases and thus may be exploited for therapeutics

ФАРМАКОКИНЕТИЧЕСКИЕ СВОЙСТВА И ЭНЗИМАТИЧЕСКИЙ ГИДРОЛИЗ ДИАЦИЛГЛИЦЕРОФОСФАТНЫХ ПРОИЗВОДНЫХ ФЛУДАРАБИНА

It is shown that the intragastric administration of 1,2- and 1,3-diacylglycerphosphate fludarabine derivatives to Wistar rats and ICR outbred mice leads to a prolonged circulation of fludarabine in animal serum in comparison with the analogous administration of equimolar fludarabine phosphate. The investigated compounds can be regarded as oral fludarabine prodrugs. It is found that the oral bioavalability of fludarabine from its 1,2-dimyristoylglycerophosphate derivative is close to its oral bioavalability from equimolar fludarabine phosphate. Based on the data of the model in vitro experiments, we can suppose that fludarabine can release from its diacylglycerphosphate prodrugs under the action of phospholipases A and D and phosphodiesterases.Установлено, что в результате внутрижелудочного введения 1,2- и 1,3-диацилглицерофосфатных производных флударабина крысам Вистар и аутбредным мышам наблюдается пролонгированное выделение и более длительная циркуляция нуклеозида в системном кровотоке животных, чем после введения эквимолярных количеств флударабина фосфата. Изученные фосфолипидные производные могут рассматриваться в качестве пероральных пролекарств флударабина. Показано, что оральная биодоступность флударабина из его 1,2-димиристоилглицерофосфатного производного у животных близка к его оральной биодоступности из эквимолярного количества флударабина фосфата. На основании данных, полученных в модельных экспериментах in vitro, можно предположить, что флударабин может выделяться из полученных пролекарств под действием ферментов, принадлежащих к семействам фосфолипаз А и Д, а также фосфодиэстераз

Temporal Dissection of K-rasG12D Mutant In Vitro and In Vivo Using a Regulatable K-rasG12D Mouse Allele

Animal models which allow the temporal regulation of gene activities are valuable for dissecting gene function in tumorigenesis. Here we have constructed a conditional inducible estrogen receptor-K-rasG12D (ER-K-rasG12D) knock-in mice allele that allows us to temporally switch on or off the activity of K-ras oncogenic mutant through tamoxifen administration. In vitro studies using mice embryonic fibroblast (MEF) showed that a dose of tamoxifen at 0.05 µM works optimally for activation of ER-K-rasG12D independent of the gender status. Furthermore, tamoxifen-inducible activation of K-rasG12D promotes cell proliferation, anchor-independent growth, transformation as well as invasion, potentially via activation of downstream MAPK pathway and cell cycle progression. Continuous activation of K-rasG12D in vivo by tamoxifen treatment is sufficient to drive the neoplastic transformation of normal lung epithelial cells in mice. Tamoxifen withdrawal after the tumor formation results in apoptosis and tumor regression in mouse lungs. Taken together, these data have convincingly demonstrated that K-ras mutant is essential for neoplastic transformation and this animal model may provide an ideal platform for further detailed characterization of the role of K-ras oncogenic mutant during different stages of lung tumorigenesis

Expression of the Stress Response Oncoprotein LEDGF/p75 in Human Cancer: A Study of 21 Tumor Types

Oxidative stress-modulated signaling pathways have been implicated in carcinogenesis and therapy resistance. The lens epithelium derived growth factor p75 (LEDGF/p75) is a transcription co-activator that promotes resistance to stress-induced cell death. This protein has been implicated in inflammatory and autoimmune conditions, HIV-AIDS, and cancer. Although LEDGF/p75 is emerging as a stress survival oncoprotein, there is scarce information on its expression in human tumors. The present study was performed to evaluate its expression in a comprehensive panel of human cancers. Transcript expression was examined in the Oncomine cancer gene microarray database and in a TissueScan Cancer Survey Panel quantitative polymerase chain reaction (Q-PCR) array. Protein expression was assessed by immunohistochemistry (IHC) in cancer tissue microarrays (TMAs) containing 1735 tissues representing single or replicate cores from 1220 individual cases (985 tumor and 235 normal tissues). A total of 21 major cancer types were analyzed. Analysis of LEDGF/p75 transcript expression in Oncomine datasets revealed significant upregulation (tumor vs. normal) in 15 out of 17 tumor types. The TissueScan Cancer Q-PCR array revealed significantly elevated LEDGF/p75 transcript expression in prostate, colon, thyroid, and breast cancers. IHC analysis of TMAs revealed significant increased levels of LEDGF/p75 protein in prostate, colon, thyroid, liver and uterine tumors, relative to corresponding normal tissues. Elevated transcript or protein expression of LEDGF/p75 was observed in several tumor types. These results further establish LEDGF/p75 as a cancer-related protein, and provide a rationale for ongoing studies aimed at understanding the clinical significance of its expression in specific human cancers