Deformation Of Nucleus Research Articles

Proton-Neutron Interactions: New Perspectives on Collective Behaviour, Deformation, and Phase Transitions in Nuclei

Proton-Neutron Interactions: New Perspectives on Collective Behaviour, Deformation, and Phase Transitions in Nuclei

Investigating the strength of the scissors mode in 151Sm

Change in nuclei deformation leads to changes in statistical properties such as the nuclear level density (NLD) and γ-ray strength function (γSF). The NLD and γSF of 151Sm were extracted using the Oslo method. The strength of the scissors resonance (SR) and its centroid energy for 151Sm were found to be 2.13 ± 0.60 and 2.48 ± 0.25 MeV, respectively. These results were used to place the SR of 151Sm and its magnetic dipole strength B(M1)SR into the context of previously measured Sm isotopes.

Multiscale Imaging of Nuclear Deformation at the Electron-Ion Collider.

We show within the color glass condensate framework that exclusive vector meson production at high energy is very sensitive to the geometric deformation of the target nucleus at multiple length scales. We show that different multipole deformation parameters affect different regions of transverse momentum transfer. These results have two important consequences: (1)Deformations of nuclear targets need to be taken into account when making predictions for and interpreting certain observables at the EIC. (2)Differential diffractive vector meson production has the potential to become a powerful tool, enabling the most direct measurements of nuclear structure at different length scales, ranging from large scale nuclear deformation at low transverse momentum transfer to fluctuations on nucleon- and subnucleon-size scales at higher transverse momentum transfer.

Shape evolution of nuclei in the region of (A≈30) using covariant density functional theory

Shape evolution of even–even isotopes of Ne, Mg, Si, S, Ar and Ca in the vicinity of [Formula: see text] mass region of the nuclear chart is studied using covariant density functional theory. It will be studied based on finite range NN-interaction force represented by NL3∗ and DD-ME2 and zero finite range NN-interaction force represented by DD-PC1. Both [Formula: see text]Mg and [Formula: see text]Si exhibit shape coexistence and the ground state shape which is found to be both oblate and prolate. The spherical shape is obtained for the Ca isotopes, and for nuclei that have magic neutron numbers [Formula: see text] and 20. The rest of the isotopic chain has only one minimum and alternates between prolate and oblate shapes. Physical properties are calculated at the location of ground state deformation with neutron number ([Formula: see text]) and proton number ([Formula: see text]), such as the binding energy, two-neutron separation energies, proton, neutron and charge radii. In general, a smooth change in these properties is found, except near [Formula: see text] and 20 one can see a sharp change, which reflects the sudden change in the ground state deformation in the neighboring nuclei. A very good agreement is found with the available experimental data, HF and FRDM models

Nesprin-1/2 facilitates breast cancer cell pore migration via nucleus deformation

Nesprin-1/2 facilitates breast cancer cell pore migration via nucleus deformation

Half-lives for proton emission and α decay within the deformed Gamow-like model

In this work, α decay and proton emission half-lives are studied by the deformed Gamow-like model, which introduces the effects of nucleus deformation. The calculations show that it is necessary to consider the deformation in the calculation for nuclei far from the shell. Moreover, this model is used to predict the proton emission half-lives of the nuclei far from the shell more accurately. The calculations indicate that our deformed model follows the Geiger-Nuttall law. Furthermore, the deformed Gamow-like model is used to study the shell structure, and we find that the number of the next neutron shell is likely to be 152. This work may benefit future research on the search for superheavy nuclei and new proton radionuclides.

Octupole deformation of nuclei near the spherical closed-shell configurations

Octupole deformation of nuclei near the spherical closed-shell configurations

Study of α-decay half-life for axially symmetric deformed even–even isotopes of nuclei with atomic numbers 88≤Z≤104

In this paper, [Formula: see text]-decay half-life of axially symmetric deformed even–even isotopes with atomic numbers [Formula: see text] had been studied for the transition between the ground states of the parent and daughter nuclei. Quadrupole deformation of daughter nuclei (if any) is considered in calculations. The interaction between the [Formula: see text]-particle and daughter nucleus includes the nuclear double-folding, the Coulomb and rotational terms. Wang’s formula is used for coulomb interaction between spherical [Formula: see text]-particle and deformed daughter nucleus. The Q-value of [Formula: see text]-decay is calculated and used to obtain its half-life, based on the WKB approximation for the penetration probability of [Formula: see text]-particle through the potential barrier. A Q-value-related formula is used to estimate the [Formula: see text]-particle preformation factor. The calculated [Formula: see text]-decay half-lives are compared with the available experimental data. The standard deviation between computed results and experimental data is obtained equal to 0.288. Comparison of our obtained standard deviation indicates well the validity of our chosen theoretical model. Furthermore, the characteristic of [Formula: see text]-decay energy and half-lives confirms the shell effects at [Formula: see text] magic number. Also, the obtained results predict similar closed shells behavior at [Formula: see text] and [Formula: see text] neutron numbers.

INVESTIGATION OF THE INFLUENCE OF THE NUCLEON PAIRING FORCE ON THE OCTUPOLE DEFORMATION OF URANIUM AND THORIUM ISOTOPES IN THE MEAN-FIELD APPROXIMATION

In the Hartree-Fock-Bogolyubov approximation and the axial symmetry of nuclei with Skyrm forces SkM*, the properties of U with A = 220 – 232 and Th with A = 218 – 230 isotopes were calculated. In addition, the properties of U and Th near the neutron drip line A = 280 – 292 were calculated. Pairing of nucleons in nuclei is described by pairing forces of zero radius of action of a mixed type with different sets of pairing force constants. In our calculations, we used constrained conditions on the parameters of quadrupole β2 and octupole β3 deformations of nuclei. It is shown that for the considered U isotopes, as well as Th isotopes, the deformation of the β3 nuclei strongly depends on the choice of the parameters of the nucleon pairing force.

Impact of nuclear deformation on collective flow observables in relativistic U+U collisions

A Multi-Phase Transport (AMPT) model is used to investigate the efficacy of several flow observables to constrain the initial-state deformation of the Uranium nuclei in U$+$U collisions at nucleon-nucleon center-of-mass energy $\sqrt{s_{\mathrm{NN}}}$ = 193 GeV. The multiparticle azimuthal cumulant method is used to investigate the sensitivity of (I) a set of quantities that are sensitive to both initial- and final-state effects as well as (II) a set of dimensionless quantities that are more sensitive to initial-state effects to the Uranium nuclei quadrupole shape deformation. I find that the combined use of the flow harmonics, flow fluctuations and correlations, linear and nonlinear flow correlations to the quadrangular flow harmonic, and the correlations between elliptic flow and the mean-transverse momentum could serve to constrain the nuclear deformation of the Uranium nuclei. Therefore, a comprehensive set of measurements of such observables can provide a quantifying tool for the quadrupole shape deformation via data-model comparisons

Investigation of giant dipole resonance in Mo isotopes within TDHF theory

The isovector giant dipole resonance (IVGDR) in the chain of even-even Mo isotopes is investigated within the time-dependent Hartree-Fock (TDHF) using the Skyrme force Sly6. The GDR calculated in Mo92−108 are presented, and compared with the available experimental data. An overall agreement between them is obtained. Moreover, the dipole strength in Mo102−108 is predicted. Shape phase transition from spherical to oblate as well as shape coexistence (A ∼ 100) in Mo isotopes are also investigated in this work. In addition, the correlation between the deformation splitting ΔE and the quadrupole deformation parameter β2 is studied. The results confirm that ΔE is proportional to the deformation of nucleus. We also discuss the dependence of GDR strength on some nuclear properties of Skyrme forces, such as the asymmetry energy as. We find that as=32 MeV, corresponding to SLy6, is quite consistent with experimental data.

Half-lives of deformed nuclei for exotic cluster decays

In this paper, we considered the cluster radioactivity half-lives for all known cluster decay modes (i.e., from $^{14}\mathrm{C}$ up to $^{34}\mathrm{Si}$) that these nuclei were first satisfied by the observed systematics [Silisteanu and Scheid, Phys. Rev. C 51, 2023 (1995), Poenaru et al., Phys. Rev. C 83, 014601 (2011); Ni et al., Phys. Rev. C 78, 044310 (2008)]. The Coulomb and proximity potential model for deformed nuclei is considered as penetration of the emitter particle through the potential barrier formed by the nuclear, Coulomb, and centrifugal interactions between the emitter particle and nucleus. The spins and parities of the parent and daughter nuclei in addition to the quadrupole $({\ensuremath{\beta}}_{2})$ and hexadecapole $({\ensuremath{\beta}}_{4})$ deformations of the parent nuclei are taken into account for the calculation of the cluster radioactivity half-lives. Our results exhibit, which the minimum $\mathrm{lo}{\mathrm{g}}_{10}{T}_{1/2}$ value denotes doubly magic $^{208}\mathrm{Pb}$ ($Z=82$, $N=126$) as the daughter nuclei.

Measurements and computational analysis of the natural decay of Lu176

Background: Mainly because of its long half-life and despite its scientific relevance, spectroscopic measurements of $^{176}\mathrm{Lu}$ forbidden $\ensuremath{\beta}$ decays are very limited and lack formulation of shape factors. A direct precise measurement of its Q value is also presently unreported. In addition, the description of forbidden decays provides interesting challenges for nuclear theory. The comparison of precise experimental results with theoretical calculations for these decays can help to test underlying models and can aid the interpretation of data from other experiments.Purpose: Perform the first precision measurements of $^{176}\mathrm{Lu}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$-decay spectra and attempt the observation of its electron capture decays, as well as perform the first precision direct measurement of the $^{176}\mathrm{Lu}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$-decay Q value. Compare the shape of the precisely determined experimental $\ensuremath{\beta}$ spectra to theoretical calculations, and compare the end point energy to that obtained from an independent Q value measurement.Method: The $^{176}\mathrm{Lu}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$-decay spectra measurements and the search for electron capture decays were performed with an experimental setup that employed lutetium-containing scintillator crystals and a NaI(Tl) spectrometer for coincidence counting. The $\ensuremath{\beta}$ decay Q value was determined via high-precision Penning trap mass spectrometry (PTMS) with the LEBIT facility at the National Superconducting Cyclotron Laboratory. The $\ensuremath{\beta}$-spectrum calculations were performed within the Fermi theory formalism with nuclear structure effects calculated using a shell model approach.Results: Both $\ensuremath{\beta}$ transitions of $^{176}\mathrm{Lu}$ were experimentally observed and corresponding shape factors formulated in their entire energy ranges. The search for electron capture decay branches led to an experimental upper limit of $6.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ relative to its $\ensuremath{\beta}$ decays. The $^{176}\mathrm{Lu}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$-decay and electron capture Q values were measured using PTMS to be 1193.0(6) and 108.9(8) keV, respectively. This enabled precise $\ensuremath{\beta}$ end point energies of 596.2(6) and 195.3(6) keV to be determined for the primary and secondary $\ensuremath{\beta}$ decays, respectively. The conserved vector current hypothesis was applied to calculate the relativistic vector matrix elements. The $\ensuremath{\beta}$-spectrum shape was shown to significantly depend on the Coulomb displacement energy and on the value of the axial vector coupling constant ${g}_{A}$, which was extracted according to different assumptions.Conclusion: The implemented self-scintillation method has provided unmatched observations of $^{176}\mathrm{Lu}$, independently validated by the first direct measurements of its $\ensuremath{\beta}$-decay Q value by Penning trap mass spectrometry. Theoretical study of the main $\ensuremath{\beta}$ transition led to the extraction of very different effective ${g}_{A}$ and ${log}_{10}\phantom{\rule{0.16em}{0ex}}f$ values, showing that a high-precision description of this transition would require a realistic nuclear structure with nucleus deformation.

The effects of the water-soluble fractions of crude oil on liver and kidney tissues of Caspian Kutum juveniles, Rutilus frisii

The lethal and histopathological impacts of crude oil's Water-Soluble Fraction (WSF) on the liver and kidney tissues of juvenile Rutilus frisii were investigated. The LC50 96 h of WSF was calculated at 33.95 ppm. Fish exposed to two concentrations (0.1 LC50 and LC50) of WSF and control for 24 and 96 h were used for histopathological studies. Tissues in the control group and 0.1 LC50–24 h were healthy, and no specific damages were observed. With increasing exposure time (96 h) and concentration (LC50), damages' type, frequency, and intensity gradually increased. Cloudy swelling, loss of cell boundary, nuclei deformation, and congestion of blood vessels were found in the liver, enlarged glomeruli, reduced Bowman's space, and occlusion of the tubular lumen, were found in the kidney. It is demonstrated that the WSF of crude oil can cause severe damage to the tissues of juvenile Kutum, depending on the exposure concentration.

Effect of deformation dependence and mirror nucleus corrections energy on multinucleon transfer reaction cross sections

Multinucleon transfer reactions are currently a powerful way to synthesize neutron-rich nuclei. To explore the effect of nucleus deformation and mirror nucleus shell correction energy in the nucleus mass model on the calculation of multinucleon transfer reaction cross sections in the dinuclear system (DNS) model, three macroscopic microscopic mass models are selected and the transfer reaction cross sections are calculated for 136Xe+208Pb and 64Ni+238U by improved DNS model+GEMINI++, respectively. The mirror nucleus shell correction energy does not improve the accuracy of the cross section of the transfer reaction. The introduction of a different dependence of the Coulomb and surface energy on the deformation can improve the calculation of the transfer reaction cross section when the projectile and target nuclei are deformed nuclei.

Binary Colloidal Crystals Promote Cardiac Differentiation of Human Pluripotent Stem Cells via Nuclear Accumulation of SETDB1

Biophysical cues can facilitate the cardiac differentiation of human pluripotent stem cells (hPSCs), yet the mechanism is far from established. One of the binary colloidal crystals, composed of 5 μm Si and 400 nm poly(methyl methacrylate) particles named 5PM, has been applied as a substrate for hPSCs cultivation and cardiac differentiation. In this study, cell nucleus, cytoskeleton, and epigenetic states of human induced pluripotent stem cells on the 5PM were analyzed using atomic force microscopy, molecular biology assays, and the assay for transposase-accessible chromatin sequencing (ATAC-seq). Cells were more spherical with stiffer cell nuclei on the 5PM compared to the flat control. ATAC-seq revealed that chromatin accessibility decreased on the 5PM, caused by the increased entry of histone lysine methyltransferase SETDB1 into the cell nuclei and the amplified level of histone H3K9me3 modification. Reducing cytoskeleton tension using a ROCK inhibitor attenuated the nuclear accumulation of SETDB1 on the 5PM, indicating that the effect is cytoskeleton-dependent. In addition, the knockdown of SETDB1 reversed the promotive effects of the 5PM on cardiac differentiation, demonstrating that biophysical cue-induced cytoskeletal tension, cell nucleus deformation, and then SETDB1 accumulation are critical outside-in signal transformations in cardiac differentiation. Human embryonic stem cells showed similar results, indicating that the biophysical impact of the 5PM surfaces on cardiac differentiation could be universal. These findings contribute to our understanding of material-assistant hPSC differentiation, which benefits materiobiology and stem cell bioengineering.

The comprehensive effect of copper oxide nanoparticles on the physiology of the diatom microalga Thalassiosira weissflogii.

The high rate of production and use of copper oxide nanoparticles (CuO NPs) results in its accumulation in the environment. However, the effect of large quantities of CuO NPs on aquatic ecosystems is not fully known. In aquatic ecosystems, phytoplankton is the primary producer of organic matter and the basis of all the trophic interactions; accordingly, the potential effect of CuO NPs on the microalgae community is of great concern. This study established the main patterns of changes in morphological, structural, functional, fluorescent and cytometric parameters in the marine diatom Thalassiosira weissflogii after adding CuO NPs to the medium at concentrations of 250-2500μgL-1. As shown, the investigated pollutant has cytotoxic, genotoxic and mechanical effect on the microalga covering almost all the aspects of cell functioning. A two-fold decrease in the culture abundance relative to the control is observed at the toxicant content of 550μgL-1 in the medium. At CuO NPs content above 750μgL-1, a pronounced inhibition of the alga growth is recorded, as well as a decrease in the efficiency of its photosynthetic apparatus, a disturbance of membrane integrity, an increase in cell volume, a rise in abundance of dead/inactive cells in the culture, enlargement and deformation of nuclei, an increase in reactive oxygen species production, and depolarisation of the mitochondrial membrane. Our results show that high CuO NPs concentrations in water can cause serious disruptions in phytoplankton functioning and in equilibrium of aquatic ecosystems in general.

Tissue fluidification promotes a cGAS–STING cytosolic DNA response in invasive breast cancer

The process in which locally confined epithelial malignancies progressively evolve into invasive cancers is often promoted by unjamming, a phase transition from a solid-like to a liquid-like state, which occurs in various tissues. Whether this tissue-level mechanical transition impacts phenotypes during carcinoma progression remains unclear. Here we report that the large fluctuations in cell density that accompany unjamming result in repeated mechanical deformations of cells and nuclei. This triggers a cellular mechano-protective mechanism involving an increase in nuclear size and rigidity, heterochromatin redistribution and remodelling of the perinuclear actin architecture into actin rings. The chronic strains and stresses associated with unjamming together with the reduction of Lamin B1 levels eventually result in DNA damage and nuclear envelope ruptures, with the release of cytosolic DNA that activates a cGAS–STING (cyclic GMP-AMP synthase–signalling adaptor stimulator of interferon genes)-dependent cytosolic DNA response gene program. This mechanically driven transcriptional rewiring ultimately alters the cell state, with the emergence of malignant traits, including epithelial-to-mesenchymal plasticity phenotypes and chemoresistance in invasive breast carcinoma.

A Review on Stimuli-Actuated 3D Micro/Nanostructures for Tissue Engineering and the Potential of Laser-Direct Writing via Two-Photon Polymerization for Structure Fabrication.

In this review, we present the most recent and relevant research that has been done regarding the fabrication of 3D micro/nanostructures for tissue engineering applications. First, we make an overview of 3D micro/nanostructures that act as backbone constructs where the seeded cells can attach, proliferate and differentiate towards the formation of new tissue. Then, we describe the fabrication of 3D micro/nanostructures that are able to control the cellular processes leading to faster tissue regeneration, by actuation using topographical, mechanical, chemical, electric or magnetic stimuli. An in-depth analysis of the actuation of the 3D micro/nanostructures using each of the above-mentioned stimuli for controlling the behavior of the seeded cells is provided. For each type of stimulus, a particular recent application is presented and discussed, such as controlling the cell proliferation and avoiding the formation of a necrotic core (topographic stimulation), controlling the cell adhesion (nanostructuring), supporting the cell differentiation via nuclei deformation (mechanical stimulation), improving the osteogenesis (chemical and magnetic stimulation), controlled drug-delivery systems (electric stimulation) and fastening tissue formation (magnetic stimulation). The existing techniques used for the fabrication of such stimuli-actuated 3D micro/nanostructures, are briefly summarized. Special attention is dedicated to structures' fabrication using laser-assisted technologies. The performances of stimuli-actuated 3D micro/nanostructures fabricated by laser-direct writing via two-photon polymerization are particularly emphasized.

Influence of pre-scission neutron emission on high-energy U238 fission studied by the Langevin approach

Background: The information about the pre-scission emitted neutrons is crucial for the fission dynamics study such as fission time scale and dissipation mechanism. Purpose: The aim is to investigate the influence of the pre-scission neutron emission on the fragments mass, total kinetic energy, and the deformation distribution at the scission point in $^{238}\mathrm{U}(n,f)$ fissions at 110, 325, and 500 MeV. Method: A three-dimensional Langevin approach considering nucleus elongation, deformation, and mass asymmetry is applied to simulate fission dynamics. The Hauser-Feshbach statistical decay model is coupled to simulate the pre-scission neutron emission. Results: The properties of the pre-scission emitted neutron are first investigated. It is found that the multiplicity and the average kinetic energy increase with increasing excitation energy. The energy carried away by neutron emission is not negligible and it leads to the multichance fission, especially for the 110 MeV case. The fragments mass, total kinetic energy, and the deformation distribution at the scission point are then calculated with and without coupling the Hauser-Feshbach statistical decay model. It is found that the calculations partially reproduce the leftward shift of the experimental fragment mass distribution at high excitation energy. The pre-scission neutron emission also causes a reduction of the average total kinetic energy by about 2 MeV and a leftward shift of the distribution. The deformation distribution shows that about 75% of the fragments are produced in spherical and prolate ellipsoid shapes. No significant influence on deformation at the scission point was found. Conclusions: For high-energy fission, the energy reduction by pre-scission neutron emission should be considered, which will lead to the multichance fission. The pre-scission neutron emission is one of the reasons for the decrease of the average mass and the leftward shift of the fission fragments mass and total kinetic energy distribution.