Journal of Nuclear Physics, Material Sciences, Radiation and Applications
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Nonfactorizable Contribution to B-Meson Decays to s-Wave Mesons
Get PDFTwo-body weak decays of bottom mesons into two pseudoscalar and pseudoscalar and vector mesons, are examined under isospin analysis to study nonfactorizable contribution
Receptor Binding Domain (RBD) Structural Susceptibility in the SARS-CoV-2 Virus Spike Protein Exposed to a Pulsed Electric Field
Get PDFSARS-CoV-2 is responsible for causing the Coronavirus disease 2019 (COVID-19) pandemic, which has so far infected more than thirty million people and caused almost a million deaths. For this reason, it has been a priority to stop the transmission of the outbreak through preventive measures, such as surface disinfection, and to establish bases for the design of an effective disinfection technique without chemical components. In this study, we performed in silico analysis to identify the conformational alterations of the SARS-CoV-2 Spike Receptor Binding Domain (RBD) caused by the effect of a pulsed electric field at two different intensities. We found that both stimuli, especially the one with the highest angular frequency and amplitude, modified the electrical charge distribution in the RBD surface and the number of hydrogen bonds. Moreover, the secondary structure was significantly affected, with a decrease of the structured regions, particularly the regions with residues involved in recognizing and interacting with the receptor ACE2. Since many regions suffered conformational changes, we calculated RMSF and ΔRMSF to identify the regions and residues with larger fluctuations and higher flexibility. We found that regions conformed by 353-372, 453-464, and 470-490 amino acid residues fluctuate the most, where the first is considered a therapeutic target, and the last has alreadybeen characterized for its flexibility. Our results indicate that a pulsed electric field can cause loss of stability in the Spike-RBD, and we were able to identify the vulnerable sites to be used as a starting point for the development of viral inhibition or inactivation mechanisms
Gamma Irradiation of Aqueos Solution of L-Aspartic Acid, L-Aspartic Acid in Solid State, and L-Aspartic Acid Adsorbed into Na-Montmorillonite: Its Relevance in Chemistry Prebiotic
Get PDFAspartic acid is an amino acid present in the modern proteins, however, is considered a primitive amino acid hence its importance in prebiotic chemistry experiments studies. In some works of prebiotic chemistry have been studied the synthesis and the stability of organic matter under high energy sources, and the role of clays has been highlighted due to clays that can affect the reaction mechanisms in the radiolytic processes. The present work is focused on the study of the role of Namontmorillonite in the gamma radiolysis processes of L-aspartic acid. Gamma radiolysis processes were carried out in three different systems a) L-aspartic acid in aqueous solution; b) L-aspartic acid in solid-state; and c) L-aspartic acid adsorbed into Na-montmorillonite. L-aspartic acid was analyzed by high-performance liquid chromatography−electrospray ionization−mass spectrometry (HPLCESI-MS). The results showed that the decomposition of L-aspartic acid considerably decreased in the presence of clay thus highlighting the protector role of clays and favors the stability of organic matter even under the possible high energy conditions of primitive environments. The principal product ofgamma radiolysis of L-aspartic acid was succinic acid produced by deamination reaction. On the other hand, when aspartic acid was irradiated in solid-state the main product was the L-aspartic acid dimer. Both radiolysis products are important for chemical evolution processes for L-aspartic acid in primitive environments
Texture One Zero Model Based on A4 Flavor Symmetry and its Implications to Neutrinoless Double Beta Decay
Get PDFNeutrinos are perhaps the most elusive particles in our Universe. Neutrino physics could be counted as a benchmark for various new theories in elementary particle physics and also for the better understanding of the evolution of the Universe. To complete the neutrino picture, the missing information whether it is about their mass or their nature that the neutrinos are Majorana particles could be provided by the observation of a process called neutrinoless double beta (0νββ) decay. Neutrinoless double beta decay is a hypothesised nuclear process in which two neutrons simultaneously decay into protons with no neutrino emission. In this paper we proposed a neutrino mass model based on A4 symmetry group and studied its implications to 0νββ decay. We obtained a lower limit on |Mee| for inverted hierarchy and which can be probed in 0νββ experiments like SuperNEMO and KamLAND-Zen.
Enhanced Fission Probability of Even-Z Fragments in the Decay of Hot and Rotating 210Rn* Compound System
Get PDFMass and charge distribution of the cross-section for the fission fragments obtained in the decay of hot and rotating compound system formed in the reaction 48Ca + 162Dy → 210Rn* at an incident energy 139.6 MeV has been calculated using the dynamical cluster-decay model. Isotopic composition for each element belonging to the symmetric mass region has been obtained. The shell closure at N=50 for light and at Z=50 for heavy mass binary fragments gives a deep minima in the fragmentation potential at touching configuration and governs the fission partition of the compound system. The fission fragments of the symmetric mass region have their dominating presence along with strong odd-even staggering i.e., even-Z fission fragments are more probable than the odd ones, similar to the observed trends of the yield
Comparative Analysis of Woods-Saxon and Yukawa Model Nuclear Potentials
Get PDFIn this paper, we model the nuclear potential using Woods-Saxon and Yukawa interaction as the mean field in which each nucleon experiences a central force due to rest of the nucleons. The single particle energy states are obtained by solving the time independent Schrodinger wave equation using matrix diagonalization method with infinite spherical well wave-functions as the basis. The best fit model parameters are obtained by using variational Monte-Carlo algorithm wherein the relative mean-squared error, christened as chi-squared value, is minimized. The universal parameters obtained using Woods-Saxon potential are found to be matched with literature reported data resulting a chi-square value of 0.066 for neutron states and 0.069 for proton states whereas the chi-square value comes out to be 1.98 and 1.57 for neutron and proton states respectively by considering Yukawa potential. To further assess the performance of both the interaction potentials, the model parameters have been optimized for three different groups, light nuclei up to 16O - 56Ni, heavy nuclei 100Sn - 208Pb and all nuclei 16O - 208Pb. It is observed that Yukawa model performed reasonably well for light nuclei but did not give satisfactory results for the other two groups while Woods-Saxon potential gives satisfactory results for all magic nuclei across the periodic table.
Heavy Particle Accompanied Fission of 284Og - A Statistical Model Study
Get PDFThe structural characteristics of SHN can be investigated through the decay of SHN. In the present work ternary fission of SHN 284Og for two proton magic fixed third fragment 48Ca and 68Ni is studied at three different excitation energies 20, 35 and 50 MeV. Interestingly, 169Yb + 67Ni + 48Ca is having larger yield values and hence it is the most favoured way of fragmentation at intermediate excitation energy 35 MeV. It is observed that, asymmetric fission is favoured over symmetric fission at all the excitation for the third fragment 48Ca. Asymmetric fission is the most favoured with the fragment combination 148Sm + 68Ni + 68Ni for fixed A3 = 68Ni at all the excitations. Unlike the Ca third fragment, near symmetric fission is also favoured with 113Ag + 103Tc + 68Ni for A3 = 68Ni at all the three excitation energies
Charged Lepton Masses as a Possible CPV Source
Get PDFWe realize a model-independent study of the so-called Tri-Bi-Maximal pattern of leptonic flavor mixing. Different charged lepton mass matrix textures are studied. In particular, we are interested in those textures with a minimum number of parameters and that are able to reproduce the current experimental data on neutrino oscillation. The textures studied here form an equivalent class with two texture zeros. We obtain a Tri-Bi-Maximal pattern deviation in terms of the charged leptons masses, leading to a reactor angle and three CP violation phases non-zero. These lastest are one CP violation phase Dirac-like and two phases Majorana-like. Also, we can test the phenomenological implications of the numerical values obtained for the mixing angles and CP violation phases, on the neutrinoless double beta decay, and in the present and upcoming experiments on long-base neutrino oscillation, such as T2K, NOvA, and DUNE
Changes of the Neutron Flux of the Nuclear Reactor Triga Mark III Since the Conversion from High to Low 235U Enrichment
Get PDFThe neutron flux of the Triga Mark III research reactor was studied using nuclear track detectors. The facility of the National Institute for Nuclear Research (ININ), operates with a new core load of 85 LEU 30/20 (Low Enriched Uranium) fuel elements. The reactor provides a neutron flux around 2 × 1012 n cm-2s-1 at the irradiation channel. In this channel, CR-39 (allyl diglycol policarbonate) Landauer® detectors were exposed to neutrons; the detectors were covered with a 3 mm acrylic sheet for (n, p) reaction. Results show a linear response between the reactor power in the range 0.1 - 7 kW, and the average nuclear track density with data reproducibility and relatively low uncertainty (±5%). The method is a simple technique, fast and reliable procedure to monitor the research reactor operating power levels
Study of the Production Cross-Sections of the Neutron-rich 184Ta and 186Ta
Get PDFSynthesizing nuclei through reactions that produce a reasonable yield is important for the experimental study of neutron-rich nuclei. In this study, the cross-section values of 184Ta and 186Ta nuclei in various experiments were reviewed and analysed. The experimental data of (n, p), (p, x) and (n, α) reactions were compared to identify the best reaction to produce these nuclei for further study. Our study shows that (n, p) reactions on natural Tungsten targets are the most feasible reactions with a good yield of the neutron-rich Tantalum isotopes. New reactions have been proposed for the effective synthesis of 184Ta and 186Ta using tritium beams on Hafnium targets. The cross-section values of the proposed reactions were calculated by PACE4 software simulations