600 research outputs found
Electric quadrupole and magnetic dipole moments of odd nuclei near the magic ones in a self-consistent approach
We present a model which describes the properties of odd-even nuclei with one
nucleon more, or less, with respect to the magic number. In addition to the
effects related to the unpaired nucleon, we consider those produced by the
excitation of the closed shell core. By using a single particle basis generated
with Hartree-Fock calculations, we describe the polarization of the doubly
magic-core with Random Phase Approximation collective wave functions. In every
step of the calculation, and for all the nuclei considered, we use the same
finite-range nucleon-nucleon interaction. We apply our model to the evaluation
of electric quadrupole and magnetic dipole moments of odd-even nuclei around
oxygen, calcium, zirconium, tin and lead isotopes. Our Random Phase
Approximation description of the polarization of the core improves the
agreement with experimental data with respect to the predictions of the
independent particle model. We compare our results with those obtained in
first-order perturbation theory, with those produced by
Hartree-Fock-Bogolioubov calculations and with those generated within the
Landau-Migdal theory of finite Fermi systems. The results of our universal,
self-consistent, and parameter free approach have the same quality of those
obtained with phenomenological approaches where the various terms of the
nucleon-nucleon interaction are adapted to reproduce some specific experimental
data. A critical discussion on the validity of the model is presented.Comment: 18 pages, 7 figures, 7 table
Magnetic excitations in nuclei with neutron excess
The excitation of the , and modes in O, O,
O, O, Ca, Ca, Ca and Ca nuclei is
studied with self-consistent random phase approximation calculations.
Finite-range interactions of Gogny type, containing also tensor-isospin terms,
are used. We analyze the evolution of the magnetic resonances with the
increasing number of neutrons, the relevance of collective effects, the need of
a correct treatment of the continuum and the role of the tensor force.Comment: 18 pages, 12 figures, 2 tables, accepted for publication in Physical
Review
Pulsed Ultrasound-Assisted Extraction as an Alternative Method to Conventional Maceration for the Extraction of the Polyphenolic Fraction of Ribes nigrum Buds: A new category of food supplements proposed by the Finnover project
Low-lying magnetic excitations of doubly-closed-shell nuclei and nucleon-nucleon effective interactions
We have studied the low lying magnetic spectra of 12C, 16O, 40Ca, 48Ca and
208Pb nuclei within the Random Phase Approximation (RPA) theory, finding that
the description of low-lying magnetic states of doubly-closed-shell nuclei
imposes severe constraints on the spin and tensor terms of the nucleon-nucleon
effective interaction. We have first made an investigation by using four
phenomenological effective interactions and we have obtained good agreement
with the experimental magnetic spectra, and, to a lesser extent, with the
electron scattering responses. Then we have made self-consistent RPA
calculations to test the validity of the finite-range D1 Gogny interaction. For
all the nuclei under study we have found that this interaction inverts the
energies of all the magnetic states forming isospin doublets.Comment: 19 pages, 13 figures, 7 tables, accepted for publication in Phys.
Rev.
The Astrocytic S100B Protein with Its Receptor RAGE Is Aberrantly Expressed in SOD1(G93A) Models, and Its Inhibition Decreases the Expression of Proinflammatory Genes
Neuroinflammation is one of the major players in amyotrophic lateral sclerosis (ALS) pathogenesis, and astrocytes are significantly involved in this process. The astrocytic protein S100B can be released in pathological states activating the receptor for advanced glycation end products (RAGE). Different indications point to an aberrant expression of S100B and RAGE in ALS. In this work, we observed that S100B and RAGE are progressively and selectively upregulated in astrocytes of diseased rats with a tissue-specific timing pattern, correlated to the level of neurodegeneration. The expression of the full-length and soluble RAGE isoforms could also be linked to the degree of tissue damage. The mere presence of mutant SOD1 is able to increase the intracellular levels and release S100B from astrocytes, suggesting the possibility that an increased astrocytic S100B expression might be an early occurring event in the disease. Finally, our findings indicate that the protein may exert a proinflammatory role in ALS, since its inhibition in astrocytes derived from SOD1(G93A) mice limits the expression of reactivity-linked/proinflammatory genes. Thus, our results propose the S100B-RAGE axis as an effective contributor to the pathogenesis of the disease, suggesting its blockade as a rational target for a therapeutic intervention in ALS
Fibronectin localization and fibrillization are affected by the presence of serum in culture media
The 3Rs: reduction and refinement through a multivariate statistical analysis approach in a behavioural study to unveil anxiolytic effects of natural extracts of Tilia Tomentosa.
Proceedings of the second Centro 3R Annual Meeting - Young Scientists | June 20-21, 2019, Genoa (Italy
Tensor effective interaction in self-consistent Random Phase Approximation calculations
We present a study of the effects of the tensor-isospin term of the effective
interaction in Hartree-Fock and Random Phase Approximation calculations. We
used finite-range forces of Gogny type, and we added to them a tensor-isospin
term which behaves, at large internucleonic distances, as the analogous term of
the microscopic interactions. The strength of this tensor force has been chosen
to reproduce the experimental energy of the lowest 0 excited state in
O, which shows large sensitivity to this term of the interaction. With
these finite-range interactions, we have studied the effects of the
tensor-isospin force in ground and excited states of carbon, oxygen, calcium,
nickel, zirconium, tin and lead isotopes. Our results show that the tensor
force affects mainly the nucleon single particle energies. However, we found
some interesting cases where also bulk nuclear properties are sensitive to the
tensor interaction.Comment: 18 pages, 14 figures, 3 table
Use of an animal model to evaluate anxiolytic effects of dietary supplementation with tilia tomentosa moench bud extracts
Anxiety disorders are common and complex psychiatric syndromes affecting a broad spectrum of patients. On top of that, we know that aging produces an increase in anxiety vulnerability and sedative consumption. Moreover, stress disorders frequently show a clear gender susceptibility. Currently, the approved pharmacological strategies have severe side effects such as hallucinations, addiction, suicide, insomnia, and loss of motor coordination. Dietary integration with supplements represents an intriguing strategy for improving the efficacy and the safety of synthetic anxiolytics. Accordingly, a recent article demonstrated that glyceric bud extracts from Tilia tomentosa Moench (TTBEs) exert effects that are consistent with anxiolytic activity. However, the effects of these compounds in vivo are unknown. To examine this question, we conducted behavioral analysis in mice. A total of 21 days of oral supplements (vehicle and TTBEs) were assessed by Light Dark and Hole Board tests in male and female mice (young, 3 months; old, 24 months). Interestingly, the principal component analysis revealed gender and age-specific behavioral modulations. Moreover, the diet integration with the botanicals did not modify the body weight gain and the daily intake of water. Our results support the use of TTBEs as dietary supplements for anxiolytic purposes and unveil age and gender-dependent responses
HIV infection and frequency of micronucleus in human peripheral blood cells
Purpose. People living with HIV have higher rates of malignancies than the general population in the era of active antiretroviral therapy (ART). Genotoxic effects of HIV infection and/or ART that can induce neoplastic development are not yet well known. A prospective cohort study to investigate DNA damage measured through the micronuclei (MN) frequency in HIV-patients has been performed. Methods. Peripheral blood mononuclear cells (PBMC) were isolated from 52 HIV-patients treated with ART and 55 healthy controls. Results. By the comparison of MN frequency, a significant difference between HIV-patients (15.5 ± 9.8) and controls (6.0 ± 3.6) (p < 0.001) has been revealed. In univariate linear regression analysis, HCV infection (r = 0.31; p < 0.001), HIV-RNA (r = 0.29; p < 0.03) and duration of infection (r = - 0.16; p < 0.25) were associated with MN frequency; while only viral load (VL) significantly correlates (r = 0.29; p < 0.05) in a multiple regression model. Conclusions. The association of VL with MN frequency supports a genotoxic effect of HIV infection
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