ANALISI DELLO STATO TENSIONALE IN RESINE EPOSSIDICHE SOTTOPOSTE AD INVECCHIAMENTO IDROTERMICO MEDIANTE TECNICA FOTOELASTICA

In questo lavoro si è analizzato lo stato tensionale che nasce in sistemi epossidici DGEBA quando sono sottoposti ad invecchiamento idro-termico, tramite la tecnica fotoelastica a trasmissione, basata sul metodo a variazione di fase di Compensazione di Tardy. I provini, monitorati ad intervalli di tempo regolari durante i processi di assorbimento e desorbimento di acqua, sono stati osservati al polariscopio circolare. La tecnica ha permesso di analizzare, sia qualitativamente, sia quantitativamente, lo stato tensionale indotto dal non uniforme “swelling” durante l’intero processo di invecchiamento. Inoltre, lo studio ha analizzato anche provini criccati di tipo Single Edge Notched Bending; l’analisi fotoelastica ha evidenziato come all’apice della cricca si crea un sistema di frange fotoelastiche peculiari, influenzato dalla presenza della singolarit

Nonischemic Donor Heart Preservation: New Milestone in Heart Transplantation History

Heart transplantation is considered the gold standard for the treatment of advanced end-stage heart failure. However, standard donors after brain death are decreasing, whereas patients on the heart transplant waitlist are constantly rising. The introduction of the ex vivo machine perfusion device has been a turning point; in fact, these systems are able to significantly reduce ischemic times and have a potential effect on ischemia-related damage reduction. From a clinical standpoint, these machines show emerging results in terms of heart donor pool expansion, making marginal donors and donor grafts after circulatory death suitable for donation. This article aims to review mechanisms and preclinical and clinical outcomes of currently available ex vivo perfusion systems, and to explore the future fields of application of these technologies

Water diffusion and swelling stresses in highly crosslinked epoxy matrices

The present work investigates the swelling induced stresses arising in two epoxy systems during water uptake. The analysed systems are two epoxy resin based on DGEBA monomer and DGEBF monomer respectively, both fully cured by DDS amine. The systems achieve different cross-link density degrees, and are characterised by high glass transition temperatures ranging between 200 and 230 °C. Both epoxies have been conditioned in deionized water baths at two different temperatures (50 °C and 80 °C). A desorption process at room temperature in a dry airborne environment was performed after saturation. Dynamic Mechanical Thermal Analysis, carried out at the various stages of hydrothermal conditioning, has allowed to characterise the modifications occurring in the network structures during aging. Photoelastic Stress Analysis is adopted to monitor the evolution of stresses on rectangular beam samples during absorption and desorption of water. Correlation of water uptake, dynamic mechanical behaviour and transitory stress fields, has allowed to make some assumptions about the influence of the epoxy network on the swelling behaviour

Comparative study of seminal parameters between samples collected in 1992 and samples collected in 2010

Objective: The aim of this study was to conduct a comparative study of semen quality in two large populations; one evaluated in 1992 and another in 2010, in order to evaluate any possible decline in male fertility due, at least in part, to environmental factors. Material and Methods: A total of 701 subjects in 1992 (TOTAL group 1992) and a total of 626 subjects in 2010 (TOTAL group 2010) were enrolled in our Andrology Unit. Each group was subdivided into 3 subgroups: Subfertile, Pathology and Control. Standard semen analysis was performed using the Superimposed Image Analysis System, according to WHO guidelines 1987 (for TOTAL group 1992) and WHO guidelines 1999 (for TOTAL group 2010). Results: The mean values of sperm number (concentration/ml as well as the total ejaculate) and progressive motility were significantly higher in TOTAL group 2010 than TOTAL group 1992. Atypical forms in TOTAL group 1992 semen samples were significantly lower than TOTAL group 2010. The mean age of TOTAL Group 2010 was significantly higher compared with TOTAL Group 1992. In particular, the mean age gap was more evident in Subfertile subjects. Conclusions: In conclusion, environmental factors have not determined a significant decline in seminal parameters in the past 18 years

A Review of Model Predictive Controls Applied to Advanced Driver-Assistance Systems

Advanced Driver-Assistance Systems (ADASs) are currently gaining particular attention in the automotive field, as enablers for vehicle energy consumption, safety, and comfort enhancement. Compelling evidence is in fact provided by the variety of related studies that are to be found in the literature. Moreover, considering the actual technology readiness, larger opportunities might stem from the combination of ADASs and vehicle connectivity. Nevertheless, the definition of a suitable control system is not often trivial, especially when dealing with multiple-objective problems and dynamics complexity. In this scenario, even though diverse strategies are possible (e.g., Equivalent Consumption Minimization Strategy, Rule-based strategy, etc.), the Model Predictive Control (MPC) turned out to be among the most effective ones in fulfilling the aforementioned tasks. Hence, the proposed study is meant to produce a comprehensive review of MPCs applied to scenarios where ADASs are exploited and aims at providing the guidelines to select the appropriate strategy. More precisely, particular attention is paid to the prediction phase, the objective function formulation and the constraints. Subsequently, the interest is shifted to the combination of ADASs and vehicle connectivity to assess for how such information is handled by the MPC. The main results from the literature are presented and discussed, along with the integration of MPC in the optimal management of higher level connection and automation. Current gaps and challenges are addressed to, so as to possibly provide hints on future developments

MetApprendo. Il primo caso di social blockchain su larga scala. Formazione continua, contrattazione collettiva e aspetti di innovazione digitale

With an interdisciplinary approach this essay investigates the implementation of a social blockchain that has the form of a digital wallet created for the metalworkers subject to the 2021 NCBA and the related paritiarian institution MetApprendo. This is considered a special pilot project aimed at modernizing the labor market activation and the application of person-centric. Section 3 describes, under the legal viewpoint, the digital wallet functioning in relation to the 2021 NCBA for metalworkers and MetApprendo. By means of the Section 4 the tech viewpoint of the digital wallet functioning is delineated. Section 5 encompasses the future application of the social blockchain and the pilot project MetApprendo

Short-term results of a randomized trial examining timing of carotid endarterectomy in patients with severe asymptomatic unilateral carotid stenosis undergoing coronary artery bypass grafting

ObjectiveThis study evaluated the timing of carotid endarterectomy (CEA) in the prevention of stroke in patients with asymptomatic carotid stenosis >70% receiving a coronary artery bypass graft (CABG).MethodsFrom January 2004 to December 2009, 185 patients with unilateral asymptomatic carotid artery stenosis >70%, candidates for CABG, were randomized into two groups. In group A, 94 patients received a CABG with previous or simultaneous CEA. In group B, 91 patients underwent CABG, followed by CEA. All patients underwent preoperative helical computed tomography scans, excluding significant atheroma of the ascending aorta or aortic arch. Baseline characteristics of the patients, type of coronary artery lesion, and preoperative myocardial function were comparable in the two groups. In group A, all patients underwent CEA under general anesthesia with the systematic use of a carotid shunt, and 79 patients had a combined procedure and 15 underwent CEA a few days before CABG. In group B, all patients underwent CEA, 1 to 3 months after CABG, also under general anesthesia and with systematic carotid shunting.ResultsTwo patients (one in each group) died of cardiac failure in the postoperative period. Operative mortality was 1.0% in group A and 1.1% in group B (P = .98). No strokes occurred in group A vs seven ipsilateral ischemic strokes in group B, including three immediate postoperative strokes and four late strokes, at 39, 50, 58, and 66 days, after CABG. These late strokes occurred in patients for whom CEA was further delayed due to an incomplete sternal wound healing or because of completion of a cardiac rehabilitation program. The 90-day stroke and death rate was 1.0% (one of 94) in group A and 8.8% (eight of 91) in group B (odds ratio [OR], 0.11; 95% confidence interval [CI], 0.01-0.91; P = .02). Logistic regression analysis showed that only delayed CEA (OR, 14.2; 95% CI, 1.32-152.0; P = .03) and duration of cardiopulmonary bypass (OR, 1.06; 95% CI, 1.02-1.11; P = .004) reliably predicted stroke or death at 90 days.ConclusionsThis study suggests that previous or simultaneous CEA in patients with unilateral severe asymptomatic carotid stenosis undergoing CABG could prevent stroke better than delayed CEA, without increasing the overall surgical risk

The organizational culture of a Brazilian public hospital

O objetivo deste estudo foi analisar a cultura organizacional de um hospital público brasileiro. Trata-se de pesquisa descritiva, com abordagem quantitativa dos dados, desenvolvida em um hospital público do Estado de São Paulo. A amostra foi composta por 52 enfermeiros e 146 técnicos e auxiliares de enfermagem. Os dados foram coletados entre janeiro e junho de 2011, sendo utilizado o Instrumento Brasileiro para Avaliação da Cultura Organizacional – IBACO. A análise dos valores organizacionais demonstrou existência de rigidez hierárquica, centralização de poder, individualismo e competição no trabalho, dificultando o desenvolvimento do trabalho em equipe. Valores de bem-estar, satisfação e motivação dos trabalhadores foram pouco considerados. Em relação às práticas organizacionais, a promoção de relações interpessoais, as práticas de educação permanente e a recompensa dos trabalhadores também foram pouco valorizadas. Fica evidenciado que modelos tradicionais de organização do trabalho sustentam as práticas de trabalho do hospital e determinam a cultura organizacional.El objetivo de este estudio fue analizar la cultura organizacional de un hospital público brasileño. Corresponde a una investigación descriptiva con enfoque cuantitativo de los datos, desarrollada en un hospital público en el estado de São Paulo. La muestra estuvo conformada por 52 enfermeras y 146 técnicos y auxiliares de enfermería. Los datos fueron recogidos entre enero y junio de 2011, y se utilizó el Instrumento Brasileño para la Evaluación de la Cultura Organizacional - IBACO. El análisis de los valores de la organización demostró la existencia de una jerarquía rígida, la centralización del poder, el individualismo y la competencia en el trabajo, dificultando el desarrollo del trabajo en equipo. Los valores de bienestar, satisfacción y motivación de los trabajadores fueron poco considerados. En relación a las prácticas de la organización, la promoción de las relaciones interpersonales, las prácticas de educación continua y las prácticas de recompensa de los trabajadores también fueron infravaloradas. Se evidencia que los modelos tradicionales de organización del trabajo soportan las prácticas de trabajo del hospital y determinan la cultura organizacional.The objective of this research was to analyze the organizational culture of a Brazilian public hospital. It is a descriptive study with quantitative approach of data, developed in a public hospital of São Paulo State, Brazil. The sample was composed by 52 nurses and 146 nursing technicians and auxiliaries. Data were collected from January to June 2011 using the Brazilian Instrument for Assessing Organizational Culture – IBACO. The analysis of the organizational values showed the existence of hierarchical rigidity and centralization of power within the institution, as well as individualism and competition, which hinders teamwork. The values concerning workers’ well-being, satisfaction and motivation were not highly valued. In regard to organizational practices, the promotion of interpersonal relationship, continuous education, and rewarding practices were not valued either. It becomes apparent that traditional models of work organization support work practices and determine the organizational culture of the hospital.