109 research outputs found
decay and evolution of low-lying structure in Ge and As nuclei
A simultaneous calculation for the shape evolution and the related
spectroscopic properties of the low-lying states, and the -decay
properties in the even- and odd-mass Ge and As nuclei in the mass
region, within the framework of the nuclear density functional
theory and the particle-core coupling scheme, is presented. The constrained
self-consistent mean-field calculations using a universal energy density
functional (EDF) and a pairing interaction determines the interacting-boson
Hamiltonian for the even-even core nuclei, and the essential ingredients of the
particle-boson interactions for the odd-nucleon systems, and of the
Gamow-Teller and Fermi transition operators. A rapid structural evolution from
-soft oblate to prolate shapes, as well as the spherical-oblate shape
coexistence around the neutron sub-shell closure , is suggested to occur
in the even-even Ge nuclei. The predicted low-energy spectra, electromagnetic
transition rates, and -decay values are in a reasonable
agreement with experiment. The predicted values reflect the
structures of the wave functions for the initial and final nuclei of
decay, which are, to a large extent, determined by the microscopic input
provided by the underlying EDF calculation.Comment: 17 pages, 14 figures, 7 table
Octupole correlations in collective excitations of neutron-rich nuclei
Octupole correlations in the low-energy collective states of neutron-rich
nuclei near the neutron number are studied within the interacting boson
model (IBM) based on the nuclear density functional theory. The constrained
self-consistent mean-field (SCMF) calculations using a universal energy density
functional and a pairing interaction provide the potential energy surfaces in
terms of the axially-symmetric quadrupole and octupole deformations for the
even-even nuclei Se, Kr, Sr, Zr, and
Mo. Spectroscopic properties are computed in terms of the IBM that
consists of the monopole , quadrupole , and octupole bosons. Strength
parameters for the boson Hamiltonian are determined by mapping the SCMF energy
surface onto the expectation value of the Hamiltonian in the boson condensate
state. At the SCMF level, no octupole deformed ground-state shape is found,
while the energy surface is generally soft in the octupole deformation at
. The predicted negative-parity yrast bands with the bandhead state
weakly depend on and become lowest in energy at in each of
the considered isotopic chains. The model further predicts finite electric
octupole transition rates between the lowest negative-parity and the
positive-parity ground-state bands.Comment: 18 pages, 13 figures, 4 table
Microscopic Formulation of Interacting Boson Model for Rotational Nuclei
We propose a novel formulation of the Interacting Boson Model (IBM) for
rotational nuclei with axially-symmetric strong deformation. The intrinsic
structure represented by the potential energy surface (PES) of a given
multi-nucleon system has a certain similarity to that of the corresponding
multi-boson system. Based on this feature, one can derive an appropriate boson
Hamiltonian as already reported. This prescription, however, has a major
difficulty in rotational spectra of strongly deformed nuclei: the bosonic
moment of inertia is significantly smaller than the corresponding nucleonic
one. We present that this difficulty originates in the difference between the
rotational response of a nucleon system and that of the corresponding boson
system, and could arise even if the PESs of the two systems were identical. We
further suggest that the problem can be cured by implementing term into the IBM Hamiltonian, with coupling constant derived from the
cranking approach of Skyrme mean-field models. The validity of the method is
confirmed for rare-earth and actinoid nuclei, as their experimental rotational
yrast bands are reproduced nicely.Comment: 5 pages, 5 figures; accepted for publication in Phys. Rev. C Rapid
Communication
Overview of Seniority Isomers
Nuclear isomers are the metastable excited states of nuclei. The isomers can
be categorized into a few classes including spin, seniority, \emph{K}, shape
and fission isomers depending upon the hindrance mechanisms. In this paper, we
aim to present an overview of seniority isomers, which is a category related to
the seniority quantum number. The discussion is mainly based on the concepts of
seniority and generalized seniority. Various aspects of seniority isomers and
their whereabouts have been covered along with the situations where seniority
mixing prevents the isomerism.Comment: To appear in the Symmetry journal's Special Issue Selected Papers
from Shapes and Symmetries in Nuclei: From Experiment to Theory (SSNET'22
Conference
Effect of day-to-day variations in adrenal cortex hormone levels on abdominal symptoms
<p>Abstract</p> <p>Introduction</p> <p>The hypothalamic-pituitary-adrenal axis is known to be related to abdominal symptoms, and the relationship between abdominal pain and cortisol secretory patterns has been previously investigated using a cross-sectional approach. Here, we investigated the effect of day-to-day variations in salivary cortisol and dehydroepiandrosterone-sulfate levels on abdominal symptoms in healthy individuals.</p> <p>Methods</p> <p>Eleven college students (4 males and 7 females) participated in this study. The participants were asked to collect their saliva immediately after awakening and before bedtime for eight consecutive days. They also completed a questionnaire about abdominal symptoms before bedtime. The linear mixed model was applied to analyze the effects of the day-by-day variability or the 8-day average adrenal hormone level (at awakening, before bedtime, slope from awakening to bedtime) on abdominal symptoms.</p> <p>Results</p> <p>The day-to-day variability of cortisol levels before bedtime was negatively related with loose stool, while the day-to-day variability of the cortisol slope was positively correlated with loose stool. A low 8-day average dehydroepiandrosterone-sulfate level at awakening was positively related with frequent bowel movements, loose stool, and long bouts of severe abdominal pain. Likewise, a low 8-day average dehydroepiandrosterone-sulfate slope was positively related with long bouts of abdominal pain.</p> <p>Conclusions</p> <p>Low cortisol levels before bedtime and a steeper diurnal cortisol slope during the day may be related to bouts of diarrhea during the day.</p
Endometrial Cancer and Hypermethylation: Regulation of DNA and MicroRNA by Epigenetics
Endometrial cancer is the seventh most common cancer in women worldwide. Therefore elucidation of the pathogenesis and development of effective treatment for endometrial cancer are important. However, several aspects of the mechanism of carcinogenesis in the endometrium remain unclear. Associations with genetic variation and mutations of cancer-related genes have been shown, but these do not provide a complete explanation. Therefore, in recent years, epigenetic mechanisms that do not involve changes in DNA sequences have been examined. Studies aimed at detection of aberrant DNA hypermethylation in cancer cells present in microscopic amounts in vivo and application of the results to cancer diagnosis have also started. Breakdown of the DNA mismatch repair mechanism is thought to play a large role in the development of endometrial cancer, with changes in the expression of the hMLH1 gene being particularly important. Silencing of genes such as APC and CHFR, Sprouty 2, RASSF1A, GPR54, CDH1, and RSK4 by DNA hypermethylation, onset of Lynch syndrome due to hereditary epimutation of hMLH1 and hMSH2 mismatch repair genes, and regulation of gene expression by microRNAs may also underlie the carcinogenic mechanisms of endometrial cancer. Further understanding of these issues may permit development of new therapies
Mobility variations in mono- and multi-layer graphene films
The electric properties of mono- and multi-layer graphene films were
systematically studied with the layer number determined by their optical
contrast. The current modulation increased monotonically with a decrease in the
layer number due to the reduction of the interlayer scattering. Carrier
mobility in the monolayer was significantly greater than that in the multilayer
due to linear dispersion relation. On the other hand, in the monolayer, carrier
transport was extremely sensitive to charged impurity density due to the
reduction in screening effect, which causes larger mobility variation.
Reduction of the charged impurity density is thus key for high mobility.Comment: 4 page
Inactivation of the Influenza Virus by a Supplemental Fermented Plant Product (Manda Koso)
Manda Koso is a commercial fermented plant product (FPP) made from 53 types of fruits and vegetables that are fermented for more than 3 years. We hypothesized that the FPP can prevent infection by influenza virus and human norovirus. Therefore, we investigated the effects of the FPP on influenza virus and feline calicivirus, a surrogate of human norovirus. We found that 10% FPP inactivated the influenza virus but not the feline calicivirus. Inhibition of the influenza virus was highly concentration-dependent: 1% and 0.3% FPP showed reduced inactivation efficacy. The effects of the FPP on the influenza virus-infected cells were investigated by addition of the FPP to the culture medium after virus infection. No suppressive effect of the FPP on influenza replication in MDCK cells was observed. The results showed that the FPP could inactivate influenza virus by affecting the virus particles
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