Inexact Bregman iteration with an application to Poisson data reconstruction

This work deals with the solution of image restoration problems by an iterative regularization method based on the Bregman iteration. Any iteration of this scheme requires to exactly compute the minimizer of a function. However, in some image reconstruction applications, it is either impossible or extremely expensive to obtain exact solutions of these subproblems. In this paper, we propose an inexact version of the iterative procedure, where the inexactness in the inner subproblem solution is controlled by a criterion that preserves the convergence of the Bregman iteration and its features in image restoration problems. In particular, the method allows to obtain accurate reconstructions also when only an overestimation of the regularization parameter is known. The introduction of the inexactness in the iterative scheme allows to address image reconstruction problems from data corrupted by Poisson noise, exploiting the recent advances about specialized algorithms for the numerical minimization of the generalized Kullback–Leibler divergence combined with a regularization term. The results of several numerical experiments enable to evaluat

Milestones in Natural Lubrication of Synovial Joints

For years, the physical and mathematical modeling of tribological phenomena in natural human synovial joints has been a great challenge for researchers and scientists. This short review aims to summarize the main findings on lubrication modeling of human synovial joints over the years, starting from first insights and then underlining the evolution of the proposed theories. The complexity of natural human synovial joints, in which biological, fluid dynamic, and tribological phenomena takes place, makes this research area fascinating for scientists from several investigation fields. This manuscript underlines the necessity of deep scientific cooperation between researchers from different branches of the involved disciplines to achieve complete knowledge of these tribo-systems by taking in to account different points of view

The molecular imaging suite: applications in nanotechnology, targeted imaging and cell tracking

The blurring of the boundaries between the disciplines of engineering and the biological sciences has revolutionized medicine. Medicine is still a science of decisionmaking under uncertainty. However, during the past 30 years, this uncertainty gradually diminished thanks to exceptional advancements in many medical specialties, particularly imaging (1). Advancements and refinements in technology have substantially broadened the range of available imaging procedures. Medical imaging has become an essential tool in preclinical research, clinical trials and medical practice

Editorial: Biotribology and Biotribocorrosion Properties of Implantable Biomaterials

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The Effect of Chemical Composition of Biological Solutions on the Tribocorrosive Behavior and Synergistic Wear of Titanium Grade V Alloys for Biomedical Applications

Currently, the impact of tribocorrosion on medical devices such as dental implants has achieved notable effects since tribocorrosion is directly correlated with the longevity of the prosthesis. In a scenario where the phenomenon involves several variables, both from the tribological and chemical fields, this work aims to investigate the effect of the chemical compositions of biological solutions on the coupling of titanium grade V-alumina. The experimental tests were performed by a reciprocating tribometer equipped with a potentiostat and by a confocal/interferometric laser microscope connected with high-performance software for particle and wear analysis. The latter was evaluated by the synergistic approach, which is commonly adopted in the scientific community, as the sum of mechanical and synergistic effects. The results underlined that sodium lactate induced the greatest volume loss as much as the greatest tribocorrosive current and friction coefficient. On the other hand, the presence of salts such as sodium chloride and sodium bicarbonate also influenced the tribocorrosive response of titanium grade V alloys. In conclusion, the analytical equation considered for synergistic wear was modified by the introduction of a novel coefficient derived from the direct relationship between the friction coefficient and synergy and compared with the experimental data, providing a determination coefficient (R2) of 0.89

Tandems as Injectors for Synchrotrons

This is a review on the use of Tandem electrostatic accelerators for injection and filling of synchrotrons to accelerate intense beams of heavy-ions to relativistic energies. The paper emphasizes the need of operating the Tandems in pulsed mode for this application. It has been experimentally demonstrated that at the present this type of accelerators still provides the most reliable and best performance