0000000000795216
AUTHOR
R. De Luca
Low-field diamagnetic response of granular superconductors at finite temperatures
We study the low-field diamagnetic response of granular superconductors at finite temperatures by means of a simple two-dimensional Josephson-junction array. The temperature effects are taken into account by inserting white-noise current sources in parallel to the resistively shunted junction circuit models of the Josephson junctions of the network. By this analysis we argue that a simplified one-dimensional description of the equivalent circuit, proposed by the authors for cylindrical granular superconductors, is still valid even in the presence of thermally activated flux jumps. A flux-creep picture for intergranular flux motion follows.
Time evolution of non-lethal infectious diseases: a semi-continuous approach.
A model describing the dynamics related to the spreading of non-lethal infectious diseases in a fixed-size population is proposed. The model consists of a non-linear delay-differential equation describing the time evolution of the increment in the number of infectious individuals and depends upon a limited number of parameters. Predictions are in good qualitative agreement with data on influenza.
Ion motion in salt water flowing under a transverse magnetic field
The problem of ion motion in an electrolyte solution flowing in a thin rectangular duct with velocity VE in the presence of a transverse magnetic field B0 is studied by means of classical mechanics and electrodynamics. Because of Lorentz force on the ions in the electrolyte solution, a so called Faraday voltage appears at the electrodes orthogonal to both the field B0 and the velocity VE. The dynamics of positive and negative ions (cations and anions, respectively) in this classical system is studied by taking into account the viscosity of the fluid and the process of charge accumulation on the opposite walls of the duct. Hydrogen production is seen to take place at one of the electrodes wh…
Impact of combination chemotherapy on toxicity in ovarian cancer: Systematic revision of literature and meta-analysis
The purpose of this statistical analysis is to demonstrate the real advantages in terms of cost-benefit of combination chemotherapy compared with single-agent chemotherapy. The trials, which are used in this meta-analysis, have been searched on PubMed database and they are phase II or randomized phase III studies with only chemotherapy regimens. In this meta-analysis were evaluated adverse effects with odds ratio (OR), which is expressed in 95% confidence intervals (95% CI). Only 4 studies contained all the set selection criteria and they were selected. The data, which were obtained, were analyzed using MedCalc Application. The combination therapy was more strongly linked to certain adverse…
Pac-Man Josephson junctions: Useful trigonometric puzzles?
Abstract Rather interesting trigonometric equations arise when considering a Josephson junction obtained by embedding a Pac-Man shaped superconducting island in between two superconducting electrodes. In the present work we unfold these equations, written in terms of the superconducting phase difference between the two electrodes, and find the current-phase relation and the maximum superconducting current of the Josephson junction network. The solution of the trigonometric equations defining the superconducting current state of the system can be proposed to advanced high-school students or to undergraduate students in an interdisciplinary lecture.
Surgeons' fear of getting infected by COVID19: A global survey
During the last three months, COVID- 19 pandemic had led to a serious backlog of operations globally, and plans for restarting operation are imperative. Recommendations for surgical activities were studied, aiming to protect the surgical staff from being infected. In the meantime, it is also important to give attention to the surgeon’s personal feeling during work. We conducted a survey to investigate global surgi- cal practices during the COVID-19 pandemic, and the surgeon’s personal feeling was also investigated in the sur- vey. In this special letter, we performed multivariate analysis to explore factors that associated with surgeon’s fear of getting infected by COVID-19.
The patient-physician relationship in the face of oncological disease: A review of literature on the emotional and psychological reactions of patients and physician
The physician-patient relationship is daily destabilized by emotional reactions and psychic defenses that cancer arises in the two partners. Continued scientific and technological progresses which were reached by medicine in recent years, and particularly oncologic clinical discoveries, increased the chance of not only survival but also healing. Nevertheless, cancer diagnosis is still a hard existential text that destabilizes everyday life, all the psychic and relational balance, inevitably causing a psychological and social change not only in the patient who is affected but also into the wide social network around him (family, friends, doctors, healthcare team). The aim of this review is t…
From microscopic to macroscopic description of Josephson dynamics in one-dimensional arrays of weakly-coupled superconducting islands
Abstract By starting from a microscopic quantum mechanical description of Josephson dynamics of a one-dimensional array of N coupled superconductors, we obtain a set of linear differential equations for the system order parameter and for additional macroscopic physical quantities. With opportune considerations, we adapt this description to two coupled superconductors, obtaining the celebrated Feynman model for Josephson junctions. These results confirm the correspondence between the microscopic picture and the semi-classical Ohta’s model adopted in describing the superconducting phase dynamics in multi-barrier Josephson junctions.
Unusual case of dorsal vertebral metastases from a male breast cancer
Introduction: Breast cancer is a malignant neoplasm arising from mammary glands and is a rare entity in the male patient. Spine is a common site for skeletal metastases. Case presentation: A 53-years-old male was admitted to our Neurosurgical unit because of an untreatable dorsal pain. He had been treated 3 years before for breast cancer. A dorsal Magnetic Resonance Imaging (MRI) evidenced pathological masses at T8 level. A total body Computed Tomography (CT) scan revealed lungs and liver metastases. After a multidisciplinary consult, a posterior T8 decompression, a radiofrequency thermoablation in T8 vertebral body followed by screws and rods fixation (T7-T9) was performed. Post-operative …
Impact of asymptomatic COVID-19 patients in global surgical practice during the COVID-19 pandemic
The rapid spread of COVID-19 has changed the global surgical care. Patients infected with COVID-19 may present without typical symptoms, and such asymptomatic patients may potentially trigger in-hospital outbreaks by transmitting the disease to health care providers and other hospitalized patients. Further, asymptomatic COVID-19 patients have worse postop- erative outcomes with an unexpectedly high morbidity and mortality, reaching 20⋅5 per cent deaths. However, we do not have objective global data on this issue. In an attempt to clarify the current global surgical practice under the COVID-19 pandemic particularly focusing on the preoperative screening of asymptomatic COVID-19 patients, we …
Non-pegylated liposomal doxorubicin plus cyclophosphamide as first-line therapy in elderly women with HER2 negative metastatic breast cancer.
Background. The use of anthracyclines in metastatic breast cancer (MBC) is limited by cumulative dose-dependent cardiotoxicity mostly in elderly women with comorbidities. The aim of this observational retrospective study was to evaluate the efficacy of non-pegylated liposomal doxorubicin (Myocet®) and cyclophosphamide in elderly women as HER2 negative first-line MBC treatment. Methods. 84 elderly women >70 years of age (median age 78 years) with MBC HER2 negative were enrolled. Performance Status in 58 patients was ECOG-0 and in 26 patients was ECOG-1. Results. The drug was well tolerated, with overall response rates were >40%, median overall survival was 16.2 months (95%CI:14.6- 18.8…
Pac-Man Josephson junctions: useful trigonometric puzzles?
Abstract Rather interesting trigonometric equations arise when considering a Josephson junction obtained by embedding a Pac-Man shaped superconducting island in between two superconducting electrodes. In the present work we unfold these equations, written in terms of the superconducting phase difference between the two electrodes, and find the current-phase relation and the maximum superconducting current of the Josephson junction network. The solution of the trigonometric equations defining the superconducting current state of the system can be proposed to advanced high-school students or to undergraduate students in an interdisciplinary lecture.