60 research outputs found

    Phase transformations in mechanically alloyed Al-Cu-Cr powders

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    Mechanical alloying was used to form a decagonal phase in the Al-Cu-Cr system. Elemental powders of Al67Cu20Cr13, Al75Cu10Cr15, Al65Cu24Cr11, Al69Cu21Cr10 and Al78Cu10Cr12 compositions (in at. %) were mechanically alloyed in a planetary ball mill. Annealing in the temperature range of 500 to 550 0C results in the formation of binary and ternary compounds including the decagonal quasicrystalline phase that was found to be stable at least up to 800 0C and was present in various amounts in all investigated alloys. No icosahedral quasicrystalline phase was found in the samples. The maximum content (95 vol. %) of decagonal quasicrystalline phase was observed for Al69Cu21Cr10 compound annealed at 635 0С. Further increase in the annealing temperature results in the quasicrystalline phase transformation into ψ-Al65Cu25Cr10 phase, which is an approximant phase to icosahedral quasicrystal

    Pionic Degrees of Freedom in Atomic Nuclei and Quasielastic Knockout of Pions by High-Energy Electrons

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    The nonlinear model of pionic condensate in nuclei by G. Preparata can be efficiently verified by investigation of the quasielastic knockout process of pions out of nuclei by high energy electrons. First, a momentum distribution (MD) of the collective pions has a bright maximum at q=0.3 Gev.Second the excitation spectrum of a recoil nucleus is concentrated at low energies E lesser than 1MeV. The results for the pion knockout from mesonic clouds of individual nucleons are absolutely different. The latter results are presented both for pion and rho-meson clouds localized on nucleons.Comment: 13 pages, 3 figure

    FACILITIES OF NON-INVASIVE ABLATION OF LIVER’S SECONDARY TUMORS (HIFU)

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    In the work are elucidates advanced approaches to local treatment of hepatic tumors. Such modalities as super-selective intra-arterial chemoembolization, cryoablation, laser and radio-frequency ablation, as well as most modern technique based on high intensity focused ultrasound (HIFU) for distant local tumor destruction are presented in a comparative format. A classification of local ablation techniques based on degree of invasiveness (factor of local tumor destruction) is proposed. The authors present through analysis of published data, describing benefits and disadvantages of all local ablation techniques, indications and contraindications, associated complications and long-term clinical outcomes

    Mechanisms of Development of Heart Failure in Chronic Kidney Disease

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    The study of scientific data over the past 5 years has shown that cardiorenal syndrome, which has a complex and multifactorial pathophysiology, is a clinical problem. Modern pharmacological methods of treatment are effective, but insufficient to satisfactorily influence or mitigate the progression of cardiorenal syndrome, therefore, the discovery of new drugs and new therapeutic strategies for cardiorenal syndrome is a high priority tas

    Аллерген-ассоциированные молекулярные паттерны: новое слово в современной аллергологии

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    Over the last decade the role of innate immunity has been known to be crucial for the activation of adaptive immune system. The main triggers that upregulate reactions of innate immunity are small exogenous molecules with conserved motifs, molecular patterns. The article discusses a variety of possible roles of molecular patterns in the immune mechanisms, including the participation of Allergen Associated Molecular Patterns (AAMPs) in allergic processes.В последнее десятилетие ни у кого не вызывает сомнения факт важности вовлечения в формирование адаптивного иммунного ответа компонентов врожденной иммунной системы. Основным триггером, вызывающим активацию врожденного иммунитета, являются молекулярные паттерны. В статье рассмотрены вопросы, касающиеся роли паттернов в механизмах иммунитета, а также освещены новые данные об аллерген-ассоциированных молекулярных паттернах

    Piezo-Responsive Hydrogen-Bonded Frameworks Based on Vanillin-Barbiturate Conjugates

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    A concept of piezo-responsive hydrogen-bonded π-π-stacked organic frameworks made from Knoevenagel-condensed vanillin–barbiturate conjugates was proposed. Replacement of the substituent at the ether oxygen atom of the vanillin moiety from methyl (compound 3a) to ethyl (compound 3b) changed the appearance of the products from rigid rods to porous structures according to optical microscopy and scanning electron microscopy (SEM), and led to a decrease in the degree of crystallinity of corresponding powders according to X-ray diffractometry (XRD). Quantum chemical calculations of possible dimer models of vanillin–barbiturate conjugates using density functional theory (DFT) revealed that π-π stacking between aryl rings of the vanillin moiety stabilized the dimer to a greater extent than hydrogen bonding between carbonyl oxygen atoms and amide hydrogen atoms. According to piezoresponse force microscopy (PFM), there was a notable decrease in the vertical piezo-coefficient upon transition from rigid rods of compound 3a to irregular-shaped aggregates of compound 3b (average values of d33 coefficient corresponded to 2.74 ± 0.54 pm/V and 0.57 ± 0.11 pm/V), which is comparable to that of lithium niobate (d33 coefficient was 7 pm/V). © 2022 by the authors.2.1.06.03, 20211572; Russian Foundation for Basic Research, РФФИ: 20-53-00043-Bel_a; Ministry of Science and Technology, Taiwan, MOST: 19-52-06004 MNTI_a; Ural Federal University, UrFU: 2968; Ministry of Science and Higher Education of the Russian Federation: 075-15-2021-677The work was supported by the Russian Foundation for Basic Research (RFBR, project no. 20-53-00043-Bel_a) and the PFM measurements were done under RFBR and MOST project no. 19-52-06004 MNTI_a. The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg. No. 2968), which is supported by the Ministry of Science and Higher Education RF (project No. 075-15-2021-677), was used. T.V.S. acknowledges the support from the State Program of Scientific Researchers of Belarus (research issue 2.1.06.03, state registration number: 20211572)

    Remote heart rate monitoring - Assessment of the Facereader rPPg by Noldus

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    Remote photoplethysmography (rPPG) allows contactless monitoring of human cardiac activity through a video camera. In this study, we assessed the accuracy and precision for heart rate measurements of the only consumer product available on the market, namely the Facereader™ rPPG by Noldus, with respect to a gold standard electrocardiograph. Twenty-four healthy participants were asked to sit in front of a computer screen and alternate two periods of rest with two stress tests (i.e. Go/No-Go task), while their heart rate was simultaneously acquired for 20 minutes using the ECG criterion measure and the Facereader™ rPPG. Results show that the Facereader™ rPPG tends to overestimate lower heart rates and underestimate higher heart rates compared to the ECG. The Facereader™ rPPG revealed a mean bias of 9.8 bpm, the 95% limits of agreement (LoA) ranged from almost -30 up to +50 bpm. These results suggest that whilst the rPPG Facereader™ technology has potential for contactless heart rate monitoring, its predictions are inaccurate for higher heart rates, with unacceptable precision across the entire range, rendering its estimates unreliable for monitoring individuals
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