19 research outputs found
Self-consistent calculations of the electric giant dipole resonances in light and heavy mass nuclei
While bulk properties of stable nuclei are successfully reproduced by
mean-field theories employing effective interactions, the dependence of the
centroid energy of the electric giant dipole resonance on the nucleon number A
is not. This problem is cured by considering many-particle correlations beyond
mean-field theory, which we do within the "Quasiparticle Time Blocking
Approximation". The electric giant dipole resonances in O, Ca,
and Pb are calculated using two new Skyrme interactions.Comment: 4 pages, 4 figure
Safety and immunogenicity of rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine against SARS-CoV-2 in healthy adolescents: an open-label, non-randomized, multicenter, phase 1/2, dose-escalation study
To protect young individuals against SARS-CoV-2 infection, we conducted an open-label, prospective, non-randomised dose-escalation Phase 1/2 clinical trial to evaluate the immunogenicity and safety of the prime-boost “Sputnik V” vaccine administered at 1/10 and 1/5 doses to adolescents aged 12–17 years. The study began with the vaccination of the older cohort (15-to-17-year-old participants) with the lower (1/10) dose of vaccine and then expanded to the whole group (12-to-17-year-old participants). Next, 1/5 dose was used according to the same scheme. Both doses were well tolerated by all age groups. No serious or severe adverse events were detected. Most of the solicited adverse reactions were mild. No significant differences in total frequencies of adverse events were registered between low and high doses in age-pooled groups (69.6% versus 66.7%). In contrast, the 1/5 dose induced significantly higher humoral and T cell-mediated immune responses than the 1/10 dose. The 1/5 vaccine dose elicited higher antigen-binding (both S and RBD-specific) as well as virus-neutralising antibody titres at the maximum of response (day 42), also resulting in a statistically significant difference at a distanced timepoint (day 180) compared to the 1/10 vaccine dose. Higher dose resulted in increased cross-neutralization of Delta and Omicron variants.;Clinical Trial RegistrationClinicalTrials.gov, NCT04954092, LP-007632
Self-consistent studies of the dipole response in neutron rich nuclei using realistic potentials
The dipole response in neutron rich nuclei is investigated within self-consistent
approaches which make direct use of a nucleon-nucleon optimized chiral potential complemented
with a density dependent term simulating a three-body force. Hartree-Fock-Bogoliubov plus
Tamm-Dancoff and random-phase approximations show that such a potential improves the
description of the dipole modes with respect to other realistic interactions. The inclusion of the
two-phonon states within an equation of motion method induces a pronounced fragmentation
of both giant and pygmy resonances in agreement with recent experiments
Unraveling cell processes: interference imaging interwoven with data analysis
The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution of hemoglobin, and that interference imaging of neurons can show intracellular compartmentalization and submembrane structures. We investigate temporal and spatial variations of the refractive index for different cell types: isolated neurons, mast cells and erythrocytes. We show that the refractive dynamical properties differ from cell type to cell type and depend on the cellular compartment. Our results suggest that low frequency variations (0.1–0.6 Hz) result from plasma membrane processes and that higher frequency variations (20–26 Hz) are related to the movement of vesicles. Using double-wavelet analysis, we study the modulation of the 1 Hz rhythm in neurons and reveal its changes under depolarization and hyperpolarization of the plasma membrane. We conclude that interference microscopy combined with wavelet analysis is a useful technique for non-invasive cell studies, cell visualization, and investigation of plasma membrane properties
Application of an extended random-phase approximation to giant resonances in light-, medium-, and heavy-mass nuclei
We present results of the time blocking approximation (TBA) on giant
resonances in light, medium and heavy mass nuclei. The TBA is an extension of
the widely used random-phase approximation (RPA) adding complex configurations
by coupling to phonon excitations. A new method for handling the
single-particle continuum is developed and applied in the present calculations.
We investigate in detail the dependence of the numerical results on the size of
the single particle space and the number of phonons as well as on nuclear
matter properties. Our approach is self-consistent, based on an energy-density
functional of Skyrme type where we used seven different parameter sets. The
numerical results are compared with experimental data.Comment: 17 pages, 12 figure