The history and current status of investigations of the unique two-step (
n
, γ
f
) reaction observed in heavy nuclei under the influence of neutrons are discussed using the example of measurements ...made on the neutron time-of-flight spectrometer GNEIS in Gatchina. It is shown what is already known and what kind of information can be derived from experiments to study the (
n
, γ
f
) reaction on resonance neutrons for the most important fissionable nuclei
235
U and
239
Pu, including information on the properties of primary gamma transitions between highly excited states near the neutron bonding energy.
Methods for the synthesis of 1,2-bis(3,4-dinitropyrazol-1-yl)diazene
(1)
, 1,2-bis(3,5-dinitropyrazol-1-yl)diazene
(2)
, and 1,2-bis(3-nitro-1,2,4-triazol-1-yl)diazene
(3)
were improved. The standard ...enthalpies of formation of these compounds were determined experimentally using combustion calorimetry. The density of compound
1
was refined. The possibilities of optimal use of the synthesized diazenes as energetic fillers for solid composite propellants (SCPs) were investigated. The main energy characteristics of SCPs containing diazenes were compared with those of the corresponding propellants based on hexanitrohexaazaisowurzitane, octogen, ammonium dinitramide, and ammonium perchlorate using thermodynamic analysis.
The experimental data on the angular distributions of fragments from the fission of
237
Np nuclei induced by 1–200 MeV neutrons have been presented. Such measurements for neutron energies above 16 ...MeV have been performed for the first time. These distributions have been analyzed and the angular anisotropy in the center-of-mass of fragments has been determined in the entire energy range under study. A method involvng the complex dynamics of the formation and decay of highly excited nuclei and based on the TALYS program has been proposed to calculate the angular distributions of fission fragments in a wide energy range for the collision of nuclei with neutrons. It has been shown that the developed model describes well the main features of the energy dependence of the angular anisotropy for the
237
Np target nuclei and can be used to extract new information on the reaction and fission process.
Clinical characteristics of disseminated intravascular coagulation (DIC) in COVID-19 infection and assessment of the effectiveness of complex therapy for this syndrome at the stages of prevention and ...treatment of various complications.
The study of publications was carried out through search engines on the Internet using keywords. To diagnose the infection, the COVID-19 program was used on the MeDiCase platform, which is publicly available on www.medicase.pro, which suggests a diagnosis with a sensitivity of 89.47%. The study included 85 patients with acute COVID-19 with mild to moderate disease, aged 11 to 81 years. The presence of the pathogen was confirmed immunologically in 12% of patients; in other cases, the diagnosis was based on the results of an automated survey in the MeDiCase system. All patients, according to the MGNOT recommendations, were prescribed one of the oral direct anticoagulants - Eliquis at a dose of 5 mg 2 times a day, Ksarelto at a dose of 10 mg 2 times a day or Pradax at a dose of 110 mg 2 times a day for at least 2 weeks. All other drugs with antiviral, immunomodulatory effects, antibiotics were canceled.
The presence of DIC is substantiated by the morphological picture of changes in organs and tissues, clinical (hematoma-petechial type of bleeding in combination with thromboembolic syndrome and the presence of thrombovasculitis) and laboratory changes: an increase in the level of soluble fibrin-monomer complexes, D-dimer, hyperfibrinogenaemia, less often - thrombocytopenia, violation of fibrinolytic activity. The phenomenon of consumption of clotting factors and profuse bleeding are rare. Direct anticoagulants, fresh frozen plasma transfusions and plasmapheresis are used in the treatment of disseminated intravascular coagulation. The paper presents its own positive results of early prescription at the outpatient stage of direct oral anticoagulants in prophylactic doses (no case of disease progression), individual cases of the use of fresh frozen plasma and plasapheresis.
DIC syndrome with the development of thrombovasculitis is the most important pathogenetic mechanism for the development of microthrombotic and hemorrhagic disorders in organs during infection with COVID-19, leading to dysfunction of the lungs, brain and other nerve tissues, kidneys, thromboembolic complications, etc. Many symptoms of the disease may be associated with a violation of the nervous regulation of the functions of organs and systems. Prevention of thrombovasculitis is effective already at the stage of the first manifestation of the disease with the outpatient use of direct anticoagulants (oral, low molecular weight heparins). In case of more severe manifestations (complications) of the disease, additional use of freshly frozen plasma and plasmapheresis is effective.
The article presents a description of the ISNP/GNEIS testing facility with a neutron spectrum that reproduces the spectrum of atmospheric neutron radiation. The facility was developed at the ...Petersburg Nuclear Physics Institute (PNPI) of the National Research Center Kurchatov Institute in collaboration with the Institute of Space Device Engineering, a branch of JSC (Joint Stock Company) United Rocket and Space Corporation. The spallation neutron source of the facility is based on the 1-GeV SC-1000 proton synchrocyclotron at the PNPI. The internal neutron-production lead target produces 10-ns pulses of neutrons with a repetition rate of 45–50 Hz and an average neutron intensity of 3 × 10
14
n/s (in the 4σ solid angle). In the irradiation area located at a distance of 36 m from the neutron source, a high-quality collimated neutron beam with a broad energy spectrum of 1–1000 MeV and a neutron flux of 4 × 10
5
n/(cm
2
s) allows conducting accelerated single-event soft error testing of electronic components. In the course of the irradiation, the neutron energy spectrum and intensity and the spatial profile of the beam are controlled using a fission ionization chamber (beam monitor) and a position-sensitive multiwire proportional counter (beam profile meter). The data acquisition system of the ISNP/GNEIS facility utilizes 250 MS/s 12 bit CAEN waveform digitizers for the processing of signals from the monitor and profile meter by the neutron time-of-flight technique. In the report, parameters of the ISNP/GNEIS testing facility are discussed in comparison with analogous world-class facilities, as well as requirements and recommendations of the standards used in this field.
In this work, we study photo-induced current transfer through nanocomposite structures consisting of the TiO2 coating activated with plasmonic gold nanoparticles on top of pillar-like structured ...SiO2. It is shown that the photo-response of the nanocomposite can be adjusted via tuning of the heterostructure topology. Processes at the interface between silicon and noble metal nanoparticle play an important role in charge carrier photo-generation. The high photo-activity in visible part of spectrum has been found in the composite, containing pillar-like silicon dioxide nanostructures 1. The electron transport via the SiO2 layer from the potential well at the TiO2-SiO2 interface to the n-Si conduction band was explained by electron tunneling mechanism. We present the empirical qualitative model which explains experimental results and helps to separate the contributions of different transport mechanisms.
Background Epidermolysis bullosa acquisita (EBA) is a chronic autoimmune subepidermal bullous disease characterized by circulating autoantibodies against type VII collagen. Detecting these ...autoantibodies is crucial for the diagnosis of this disease, and is also useful for measuring disease activity. Enzyme‐linked immunosorbent assay (ELISA), a quantitative method to measure anti‐type VII collagen antibody levels, is currently available to diagnose EBA.
Objective The aim of this study was to investigate the relationship of ELISA with overall clinical severity.
Methods Sera from patients with EBA (n = 30), bullous pemphigoid (n = 20), anti‐laminin γ1 pemphigoid (n = 9) and healthy donors (n = 24) were tested using ELISA, using the recombinant non‐collagenous 1 (NC1) and 2 (NC2) domains of type VII collagen. Relationships between clinical characteristics, indirect immunofluoroscence (IIF) titres and ELISA values were investigated.
Results The sensitivity and specificity of the EBA ELISA were 96.7% and 98.1%, respectively. There was no significant difference between ELISA results for classic and inflammatory types. The severity of skin involvement was positively correlated with both ELISA value (r = 0.87, P < 0.01) and IIF titre (r = 0.59, P < 0.01). Time sequence analysis in four patients with EBA showed that ELISA values reflect disease activity better than IIF titres.
Conclusions Type VII collagen ELISA using the NC1 and NC2 domains is useful for diagnosing EBA and monitoring disease severity.
The study of fuel mixtures with palm oil Oshchepkov, P P; Smirnov, S V; Zaev, I A ...
IOP conference series. Materials Science and Engineering,
11/2019, Letnik:
675, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The search for alternative fuels for heat engines is an urgent task for scientists around the world. For diesel engines, vegetable oils seem to be the most promising. The use of a partial addition of ...vegetable oils to diesel fuel allows us to reduce the consumption of hydrocarbons and not cause significant changes in the design of the engine, as well as affect the composition of the exhaust gases. For countries producing palm oil, including Nigeria, this method is economically viable. This article presents the results of computational studies of the features of the combustion process of biodiesel fuel with additives of palm oil and hydrogen peroxide and the effect of additives on the ignition delay period and the combustion process. The calculations have shown the effectiveness of using hydrogen peroxide as an additive to the biofuel under consideration to reduce the ignition delay period and, consequently, improve the power and economic indicators.
Although nanoparticles of heavy metal xanthates and their hydrosols can play important roles in froth flotation, environmental issues, analytics, and manufacturing of metal sulfide nanocomposites, ...they have received little attention. We studied colloidal solutions and immobilized particles prepared via interaction of aqueous lead nitrate with alkyl xanthates applying UV–vis absorption spectroscopy, dynamic light scattering, zeta potential measurement, thermogravimetry analysis, Fourier transform infrared spectroscopy, Raman scattering, X-ray photoelectron spectroscopy, atomic force microscopy, and transmission electron microscopy. The hydrodynamic diameter of colloidal particles of Pb(SSCOR)2 decreased from 500 to 50 nm with an increase in the alkyl radical length and the initial xanthate to lead ratio (X/Pb); the zeta potential magnitude varied similarly, although it remained negative. The effect of pH in the range of 4.5–11 was minor, but the colloids produced using excess of Pb2+ in alkaline media were close to PbX and decomposed much easier than PbX2. The uptake of lead xanthates on supports was generally low because of negative charges of the colloids; however, 50–100 nm thick PbX2 films were deposited on PbS and SiO2 from the media of X/Pb < 2 and pH < 9 because of preadsorption of Pb2+, while nanorods formed on highly oriented pyrolytic graphite.
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