Experimental test and numerical shape optimization of a point pivoted absorber for wave energy conversion

This paper presents a numerical study on an innovative system for converting energy from waves. It consists of a point pivoted body which oscillates in presence of waves. The system uses a linear electrical generator which converts floating movements of the buoyant body into electrical power. The buoyant body floats, describing an arc, by means of two hinges. A suitable Power Take-off Device (PTO) is placed between buoy support arms and the fixed structure and has the function to convert the mechanical power of the linear oscillating motion of the connecting piston into electrical power. A design assumption is made on the PTO control system: PTO reaction force is assumed to be linearly dependent on piston oscillation velocity with a given force-speed gain. This coefficient is strictly connected to electrical generator characteristics and its value has an effect on power conversion efficiency . A scaled model of this system has also been tested in the wave/towing tank facility of Department of industrial Engineering (DII) of University of Naples “Federico II”. A variety of numerical analyses, such as potential flow simulations and Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations, have been performed to predict the system performances. Numerical and experimental analyses have included the performances of the baseline geometry, both in free response and under wave excitation, in order to characterize the response of the system, and results have been used to understand which parameters affect more the power production. Finally a numerical optimization procedure has been carried out to optimize the shape of the converter with the final objective of increasing the generated power, eventually imposing a constraint on the amount of immersed volume. In this way, a modified configuration has been predicted with higher power output and the same value of submerged volume, but with different shape

Beam diagnostics for charge and position measurements in ELI-NP GBS

The advanced source of Gamma-ray photons to be built in Bucharest (Romania), as part of the ELI-NP European Research Infrastructure, will generate photons by Compton back-scattering in the collision between a multi-bunch electron beam and a high intensity recirculated laser pulse. An S-Band photoinjector and the following C-band Linac at a maximum energy of 720MeV, under construction by an European consortium (EurogammaS) led by INFN, will operate at 100Hz repetition rate with trains of 32 electron bunches, separated by 16ns and a 250pC nominal charge. The different BPMs and current transformers used to measure transverse beam position and charge along the LINAC are described. Design criteria, production status and bench test results of the charge and position pickups are reported in the paper, together with the related data acquisition systems

Colonic metastasis from breast carcinoma detection by CESM and PET/CT: A case report

Introduction: Metastatic spread in invasive lobular carcinoma (ILC) of breast mainly occurs in bones, gynecological organs, peritoneum, retroperitoneum, and gastrointestinal (GI) tract. Metastases to the GI tract may arise many years after initial diagnosis and can affect the tract from the tongue to the anus, stomach being the most commonly involved site. Clinical presentations are predominantly nonspecific, and rarely asymptomatic. CEA, CA 15-3, and CA 19-9 may be informative for symptomatic patients who have had a previous history of breast cancer. Case presentation: We introduce the case of asymptomatic colonic metastasis from breast carcinoma in a 67-year-old woman followed-up for Luminal A ILC. Diagnosis was performed through positron emission tomography/computed tomography (PET/CT) scan and contrast-enhancement spectral mammography (CESM), steering endoscopist to spot the involved intestinal tract and in ruling out further dissemination in the breast parenchyma. Conclusion: In colonic metastases, tumor markers might not be totally reliable. In asymptomatic cases, clinical conditions might be underappreciated, missing local or distant recurrence. CT and PET/CT scan might be useful in diagnosing small volume diseases, and steering endoscopist toward GI metastasis originating from the breast. CESM represents a tolerable and feasible tool that rules out multicentricity and multifocality of breast localization. Moreover, particular patients could tolerate it better than magnetic resonance imaging (MRI)

Post-stroke depression increases disability more than 15% in ischemic stroke survivors: a case-control study

We performed a retrospective, case-control study in consecutive ischemic stroke patients admitted to our stroke rehabilitation unit. Patients were matched for severity of neurological impairment (evaluated with the Canadian Neurological Scale, CNS), age (difference within 1 year), and onset admission interval (difference within 3 days). Participants were divided into two subgroups according to the presence or absence of PSD. Aim was to assess the specific influence of post-stroke depression (PSD) and antidepressant treatment on both basal functional status and rehabilitation outcomes. All PSD patients were treated primarily with serotoninergic antidepressants (AD). The final sample included 280 patients with depression (out of 320 found in a whole case series of 993 ischemic patients, i.e., 32.25%) and 280 without depression. Forty patients with depression were excluded because they had a history of severe psychiatric illness or aphasia, with a severe comprehension deficit. On one hand, PSD patients obtained lower Barthel Index (BI) and Rivermead Mobility Index (RMI) scores at both admission and discharge, with minor effectiveness of rehabilitative treatment and longer length of stay; on the other hand, this group had a lower percentage of dropouts. Lastly, PSD patients showed a different functional outcome, based on their response to antidepressant therapy, that was significantly better in responders than in non-responders (13.13%). Our results confirm the unfavorable influence of PSD on functional outcome, despite pharmacological treatment

Biomarkers changes after neoadjuvant chemotherapy in breast cancer: A seven-year single institution experience

The adoption of neoadjuvant chemotherapy (NACT) for breast cancer (BC) is increasing. The need to repeat the biomarkers on a residual tumor after NACT is still a matter of debate. We verified estrogen receptors (ER), progesterone receptors (PR), Ki67 and human epidermal growth factor receptor 2 (HER2) status changes impact in a retrospective monocentric series of 265 BCs undergoing NACT. All biomarkers changed with an overall tendency toward a reduced expression. Changes in PR and Ki67 were statistically significant (p = 0.001). Ki67 changed in 114/265 (43.0%) cases, PR in 44/265 (16.6%), ER in 31/265 (11.7%) and HER2 in 26/265 (9.8%). Overall, intrinsic subtype changed in 72/265 (27.2%) cases after NACT, and 10/265 (3.8%) cases switched to a different adjuvant therapy accordingly. Luminal subtypes changed most frequently (66/175; 31.7%) but with less impact on therapy (5/175; 2.8%). Only 3 of 58 triple-negative BCs (5.2%) changed their intrinsic subtype, but all of them switched treatment. No correlation was found between intrinsic subtype changes and clinicopathological features. To conclude, biomarkers changes with prognostic implications occurred in all BC intrinsic subtypes, albeit they impacted therapy mostly in HER2 negative and/or hormone receptors negative BCs. Biomarkers retesting after NACT is important to improve both tailored adjuvant therapies and prognostication of patients

Accuracy and reproducibility of contrast-enhanced mammography in the assessment of response to neoadjuvant chemotherapy in breast cancer patients with calcifications in the tumor bed

This study aimed to evaluate contrast-enhanced mammography (CEM) accuracy and reproducibility in the detection and measurement of residual tumor after neoadjuvant chemotherapy (NAC) in breast cancer (BC) patients with calcifications, using surgical specimen pathology as the reference. Pre-and post-NAC CEM images of 36 consecutive BC patients receiving NAC in 2012–2020, with calcifications in the tumor bed at diagnosis, were retrospectively reviewed by two radiologists; described were absence/presence and size of residual disease based on contrast enhancement (CE) only and CE plus calcifications. Twenty-eight patients (77.8%) had invasive and 5 (13.9%) in situ-only residual disease at surgical specimen pathology. Considering CE plus calcifications instead of CE only, CEM sensitivity for invasive residual tumor increased from 85.7% (95% CI = 67.3–96%) to 96.4% (95% CI = 81.7–99.9% ) and specificity decreased from 5/8 (62.5%; 95% CI = 24.5–91.5%) to 1/8 (14.3%; 95% CI = 0.4–57.9%). For in situ-only residual disease, false negatives decreased from 3 to 0 and false positives increased from 1 to 2. CEM pathology concordance in residual disease measurement increased (R squared from 0.38 to 0.45); inter-reader concordance decreased (R squared from 0.79 to 0.66). Considering CE plus calcifications to evaluate NAC response in BC patients increases sensitivity in detection and accuracy in measurement of residual disease but increases false positives

Effects of Walking Endurance Reduction on Gait Stability in Patients with Stroke

Control of gait is usually altered following stroke, and it may be further compromised by overexertion and fatigue. This study aims to quantitatively assess patients' gait stability during six-minute walking, measuring upper body accelerations of twenty patients with stroke (64 ± 13 years old) and ten age-matched healthy subjects (63 ± 10 years old). Healthy subjects showed a steady gait in terms of speed and accelerations over the six minutes. Conversely, the patients unable to complete the test (n = 8) progressively reduced their walking speed (−22 ± 11%, confidence interval CI95%: −13, −29%, P = 0.046). Patients able to complete the test (n = 12) did not vary their walking speed over time (P = 0.493). However, this ability was not supported by an adequate capacity to maintain their gait stability, as shown by a progressive increase of their upper body accelerations (+5 ± 11%, CI95%: −1; +12%, P = 0.010). Walking endurance and gait stability should be both quantitatively assessed and carefully improved during the rehabilitation of patients with stroke

Temperature analysis in the shock waves regime for gas-filled plasma capillaries in plasma-based accelerators

Plasma confinement represents a crucial point for plasma-based accelerators and plasma lenses because it can strongly affect the beam properties. For this reason, an accurate measurement of the plasma parameters, as plasma temperature, pressure and electron density, must be performed. In this paper, we introduce a novel method to detect the plasma temperature and the pressure for gas-filled capillaries in use at the SPARC-LAB test facility. The proposed method is based on the shock waves produced at the ends of the capillary during the gas discharge and the subsequent plasma formation inside it. By measuring the supersonic speed of the plasma outflow, the thermodynamic parameters have been obtained both outside and inside the capillary. A plasma temperature around 1.4 eV has been measured, that depends on the geometric properties and the operating conditions of the capillary

Focusing of high-brightness electron beams with active-plasma lenses

Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices