295 research outputs found

    Accurate simultaneous lead stopping power and charge-state measurements in gases and solids:Benchmark data for basic atomic theory and nuclear applications

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    We have measured for the first time simultaneously both the mean charge states and stopping powers of (35–280) MeV/u 208Pb ions in gases and solids with an accuracy of 1%. The existence at lower energies and disappearance at higher of density effects in the charge-state distribution and the corresponding stopping power are directly confirmed and comparisons with widely used theories and simulations for heavy ions demonstrate strong deviations of up to 27%. However, an unprecedented prediction power of better than 3% has been achieved for the energy loss when the measured mean charge-states are implemented in the Lindhard-Sørensen theory. Our present benchmark data contribute to an improved understanding of the basic atomic collision processes and to numerous applications in nuclear physics. Extending the GANIL data [1] to higher accuracy and energies, we can now answer at which velocities the Bohr-Lindhard density effect in stopping will vanish.</p

    Spectroscopy of η<sup>0</sup>-mesic nuclei with WASA at GSI/FAIR

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    We plan to conduct an experimental search for η0-mesic nuclei in order to investigate in-medium properties of the η0 meson. A 2.5 GeV proton beam is employed to produce η0-mesic 11C nuclei with the 12C(p,d)η0⊗ 11C reaction. Simultaneous measurements of the forward ejected deuterons and decay protons from η0-mesic nuclei will allow us to achieve high experimental sensitivity. The experiment will be performed at GSI by making full use of the fragment separator FRS and the WASA detector system. The plan of this proposed experiment is described.</p

    WASA-FRS EXPERIMENTS IN FAIR PHASE-0 AT GSI

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    We have developed a new and unique experimental setup integrating the central part of the Wide Angle Shower Apparatus (WASA) into the Fragment Separator (FRS) at GSI. This combination opens up possibilities of new experiments with high-resolution spectroscopy at forward 0◦ and measurements of light decay particles with nearly full solid-angle acceptance in coincidence. The first series of the WASA-FRS experiments have been successfully carried out in 2022. The developed experimental setup and two physics experiments performed in 2022 including the status of the preliminary data analysis are introduced.</p

    Studies of three-and four-body hypernuclei with heavy-ion beams, nuclear emulsions and machine learning

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    Interests on few-body hypernuclei have been increased by recent results of experiments employing relativistic heavy ion beams. Some of the experiments have revealed that the lifetime of the lightest hypernucleus, hypertriton, is significantly shorter than 263 ps which is expected by considering the hypertriton to be a weakly-bound system. The STAR collaboration has also measured the hypertriton binding energy, and the deduced value is contradicting to its formerly known small binding energy. These measurements have indicated that the fundamental physics quantities of the hypertriton such as its lifetime and binding energy have not been understood, therefore, they have to be measured very precisely. Furthermore, an unprecedented Λnn bound state observed by the HypHI collaboration has to be studied in order to draw a conclusion whether or not such a bound state exists. These three-body hypernuclear states are studied by the heavy-ion beam data in the WASA-FRS experiment and by analysing J-PARC E07 nuclear emulsion data with machine learning.</p

    Magnetostimulated inhomogeneity of electric field in aluminum

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    The results of low temperature experimental and theoretical study of potential distribution of stationary electric field in Al under the action of inhomogeneous magnetic field are presented

    On the appearance of space temperature electric structures in hyperconductors under high magnetic fields

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    As part of the study of low temperature galvanomagnetic properties of high purity A1 in the Corbino geometry the voltage-current characteristics (IV) under external transverse magnetic field in the regime of given current revealed the effects of voltage stabilization. Here we attempt to ascribe these phenomena to appearance in the sample of bulk temperature structures characteristic of highly nonequilibrium systems. Joule’s heat of flowing electric current gives rise to disk warming. We also discuss the problems of the influence of warming in disks on the phenomena of electric transport with allowance for own magnetic fields being generated in disk

    Genetic approaches to the investigation of serotonergic neuron functions in animals

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    The serotonergic system is one of the most important neurotransmitter systems that take part in the regulation of vital CNS functions. The understanding of its mechanisms will help scientists create new therapeutic approaches to the treatment of mental and neurodegenerative diseases and find out how this neurotransmitter system interacts with other parts of the brain and regulates their activity. Since the serotonergic system anatomy and functionality are heterogeneous and complex, the best tools for studying them are based on manipulation of individual types of neurons without affecting neurons of other neurotransmitter systems. The selective cell control is possible due to the genetic determinism of their functions. Proteins that determine the uniqueness of the cell type are expressed under the regulation of cell-specific promoters. By using promoters that are specific for genes of the serotonin system, one can control the expression of a gene of interest in serotonergic neurons. Here we review approaches based on such promoters. The genetic models to be discussed in the article have already shed the light on the role of the serotonergic system in modulating behavior and processing sensory information. In particular, genetic knockouts of serotonin genes sert, pet1, and tph2 promoted the determination of their contribution to the development and functioning of the brain. In addition, the review describes inducible models that allow gene expression to be controlled at various developmental stages. Finally, the application of these genetic approaches in optogenetics and chemogenetics provided a new resource for studying the functions, discharge activity, and signal transduction of serotonergic neurons. Nevertheless, the advantages and limitations of the discussed genetic approaches should be taken into consideration in the course of creating models of pathological conditions and developing pharmacological treatments for their correction

    Novel concept of hyperconducting concentrator of magnetic energy

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    The properties of Hall drift of electrons and generation of respective self magnetic field are examined. The problem of design of high effective cryogenic generator of magnetic field advances the requirement of optimization of magnetic system geometry for the most magnitude of field to be obtained in the same volume at the same energy supply. Besides an electron drift along electric field there is a transverse drift of carriers stimulated by Lorentz force if magnetic field is applied. Generally transverse Hall drift as a source of magnetic field is ignored. A paper is represented here to indicate a novel way of improvement of magnetic system arrangement and efficiency. It is based on validity of use the energy concentrator made from high purity aluminum. Such concentrator may be installed into traditional solenoid and as a consequence the magnitude of magnetic field will increase. An experiment on A1 disk conductors having inner and outer concentric current leads is made in coaxial magnetic field of 8T. Current density is sufficient to achieve a boiling crisis of helium. It is shown that magnetic field of solenoid will be increased in volume of concentrator in accordance with power type law instead of summation taking place in many layer solenoid system. The benefits and advantages of application of magnetic field of Hall drift arc discussed. Parameters together with all necessary requirement for operation are represented for cryogenic range of temperature 4.2–30 K. Research is supported by Fund of Fundamental Investigations of the Republic of Belarus

    Quantification of C1 esterase inhibitor in human serum by enzyme-linked immunosorbent assay: Correlation with turbidimetric immunoassay

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    C1 inhibitor of serine proteases (C1-INH) performs a regulatory function in the complement system and vascular permeability. Deficiency of C1-INH leads to various forms of angioedema, including hereditary angioedema (HAE). The cause of HAE is a genetically determined violation of the synthesis of C1-INH. A decrease in the level of C1-INH to 50% relative to the norm leads to an increase in the production of bradykinin, which is the basis for the diagnosis of HAE. The development of affordable ELISA for the quantitative determination of C1-INH is a popular direction for clinicians. During the development of a new kit for quantitative determination of C1-INH, two mouse monoclonal antibodies (mAb) with different epitope specificities were obtained. On their basis, a sandwich-type ELISA was developed. The specificity of the obtained mAb's was confirmed using the medical device “Berinert”. To prepare calibrators, C1-INH was affinity purified from human blood plasma using a sorbent with immobilized mAbs. The identity of the C1-INH protein was confirmed by PAGE electrophoresis, immunoblotting, and mass spectrometry on MALDI-TOF/TOF UltrafleXtreme mass spectrometer. To assess the quality indicators of developed reagents kit, studies were carried out in accordance with GOST R 51352-2013 and TU 21.20.23-041-01967164-2022. Values of quality indicators: accuracy — 93.53%; measurement linearity interval — 22.00-176.07 ng/mL. Using the developed ELISA test system, we examined 28 blood sera from healthy donors and 7 blood sera from patients with confirmed HAE. In the same samples, the content of C1-INH was determined by turbidimetric method, using the "Diagnostic reagents for in vitro immunochemical studies of specific blood proteins. Model: C1-esterase inhibitor (C1 EsteraseInhibitor)" (Aptec, Belgium). The correlation coefficient was 0.94 (p &lt; 0.05). It was found that the diagnostic sensitivity and specificity of the developed ELISA is 100%. As a result of the study, an original ELISA test system for the quantitative determination of C1-INH was developed "Reagent kit for enzyme-linked immunosorbent assay of human C1-inhibitor (C1-inh PS)"

    МЕТОД АТОМНО-СИЛОВОЙ МИКРОСКОПИИ В ИССЛЕДОВАНИИ ТРОМБОЦИТОВ ПАЦИЕНТОВ С ТЕРМИНАЛЬНОЙ СТАДИЕЙ ХРОНИЧЕСКОЙ СЕРДЕЧНОЙ НЕДОСТАТОЧНОСТИ

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    Atomic force microscopy was used to estimate the intravascular platelet activation and determine local elastic modulus, adhesion and stiffness of the platelets membrane in patients with end-stage of chronic heart failure with heart ventricle implantation before surgery and intrasurgical: before the heparin injection, after the heparin injection and after neutralization of heparin with protamine.Методом атомно-силовой микроскопии производилась оценка внутрисосудистой активации тромбоцитов и определялись локальный модуль упругости, адгезия, жесткость мембраны тромбоцитов у пациентов с терминальной стадией хронической сердечной недостаточности с использованием имплантируемого двухжелудочкового вспомогательного сердца на этапах до операции и интраоперационно: до введения гепарина, после введения гепарина, после нейтрализации гепарина протамином
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