139 research outputs found
C'è Vita su Marte?
No full textUna raccolta di interviste esclusive a dieci importanti personalità del mondo della scienza e dell'aerospazio, con un duplice obiettivo: da un lato, scattare una fotografia sullo stato attuale del settore spaziale, raccontandone i diversi aspetti dal punto di vista dei suoi protagonisti; dall'altro, proiettare lo sguardo del lettore verso il futuro, concentrandosi sulle prossime missioni di esplorazione planetaria, robotica e con equipaggio umano, non solo alla volta del Pianeta Rosso, ma anche della Luna e di altri corpi celesti, che vedono e vedranno l'Italia in prima fila. Attraverso il punto di vista di questo dream team spaziale, accompagnato da una bella selezione di immagini, l'Autore approfondisce alcuni fra i temi di maggior interesse e attualità, con riferimenti anche alla recente pandemia di coronavirus, all'importante ruolo della medicina spaziale e alle ricerche scientifiche in campo biomedico condotte in condizioni di microgravità sulla Stazione Spaziale Internazionale, tratteggiando un quadro in cui l'esplorazione planetaria non è che il filo conduttore, il pretesto, per intraprendere un viaggio nello spazio e nel futuro di più ampio respiro. Prefazione di Luca Parmitano. Interviste a: Piero Angela, Giorgio Bianciardi, Piero Bianucci, Walter Cugno, Giancarlo Genta, Vincenzo Giorgio, Paolo Nespoli, Linda Raimondo, Liliana Ravagnolo, Giorgio Saccoccia
Pharmaconutrition: Which substrates?
No full textWith the term “pharmaconutrition” or “immunonutrition” is intended the use of specific nutritional substrates having the ability of modulating specific mechanisms involved in several immune and inflammatory pathways. To achieve these goals, these substrates have to be administered with over physiologic dose. Glutamine and omega-3 polyunsaturated fatty acids, used as single substrate, did not show clear clinical advantages on solid endpoints such as postoperative complications. Despite several multiple substrate enteral feeds are available on the market, very few of them have been tested in randomized clinical trial to prove efficacy. The most extensive investigated formulation is a combination of arginine, omega-3 fatty acids, ribonucleic acid with or without glutamine. Several meta-analyses of randomized clinical trials have been conducted to compare the effects of enteral immunonutrition with control diets on post-surgical morbidity. The results consistently showed that the use of enteral multiple substrate formulas significantly reduced infectious complications and duration of hospitalization. In a more contemporary view, pharmaconutrition should be tested more accurately in the contest of enhanced recovery programs, during neoadjuvant chemotherapy, and in the prehabilitation setting
Correction to: The decrease of non-complicated acute appendicitis and the negative appendectomy rate during pandemic (European Journal of Trauma and Emergency Surgery, (2021), 10.1007/s00068-021-01663-7)
No full textThe original version of this article unfortunately contained a mistake. The Acknowledgement with the members of the Appendicitis- COVID study group is missing. The correct version of is given below. Acknowledgements Members of the Appendicitis-COVID study group: Monza: Marco Nizzardo, Luca Nespoli, Luca Fattori, Luca Degrate, Stefano Perrone, Marco Cereda Bergamo: Michele Pisano, Elia Poiasina, Paolo Bertoli Lodi: Michele Ballabio, Stefano Braga Pavia: Giorgio Graziano Pisa: DarioTartaglia, Francesco Arces Lecco: Marco Mariani, Fulvio Tagliabue Parma: Gennaro Perrone, Alfredo Annicchiarico, Mario Giuffrida Legnano: Giovanni Ferrari, Antonio Benedetti, Niccolò Allievi Ponte San Pietro: Michele Ciocca, Enrico Pinotti, Mauro Montuori San Raffaele: Michele Carlucci, Valentina Tomajer Cesena: Paola Fugazzola The original article has been corrected
Experimental and Numerical Characterization of an Oil-Free Scroll Expander
No full textMicro-ORC systems are characterized by low efficiency values, but at the same time could be used as energy recovery systems in domestic applications for which reliability and low noise level represent the biggest challenges. In this paper, an integrated Reverse Engineering (RE)-Computational Fluid Dynamics (CFD) methodology is applied in order to study the adaptation of a commercial scroll compressor to be used as an expander in a micro-ORC system. The analyses reported in this paper consist of: (i) the acquisition of the 5-kW oil-free scroll expander through a RE procedure and its CAD reconstruction, (ii) the set-up of fully three-dimensional transient simulations with the Chimera strategy using the Siemens PLM software, (iii) the validation of the computational analysis by means of experimental tests and finally, (iv) the analysis of the geometry-flow features like flank and axial gaps, coupled with the analysis of the scroll volumetric efficiency and overall performance. Chimera strategy is able to move the computational grid at each time step in order to accommodate the shape and size changes of the gas pockets. The scroll characterization was carried out using both experimental and numerical tests. Six different rotational velocities in the range of (400 - 2400) rpm with a fixed pressure level (7.5 bar) were tested for validating the numerical model using air as a working fluid. The numerical model was then used to calculate the scroll expander performance operating in an existing ORC system with R134a as working fluid
Battery Sizing for Different Loads and RES Production Scenarios through Unsupervised Clustering Methods
No full textThe increasing penetration of Renewable Energy Sources (RESs) in the energy mix is determining an energy scenario characterized by decentralized power production. Between RESs power generation technologies, solar PhotoVoltaic (PV) systems constitute a very promising option, but their production is not programmable due to the intermittent nature of solar energy. The coupling between a PV facility and a Battery Energy Storage System (BESS) allows to achieve a greater flexibility in power generation. However, the design phase of a PV+BESS hybrid plant is challenging due to the large number of possible configurations. The present paper proposes a preliminary procedure aimed at predicting a family of batteries which is suitable to be coupled with a given PV plant configuration. The proposed procedure is applied to new hypothetical plants built to fulfill the energy requirements of a commercial and an industrial load. The energy produced by the PV system is estimated on the basis of a performance analysis carried out on similar real plants. The battery operations are established through two decision-tree-like structures regulating charge and discharge respectively. Finally, an unsupervised clustering is applied to all the possible PV+BESS configurations in order to identify the family of feasible solutions
A high visceral adipose tissue-to-skeletal muscle ratio as a determinant of major complications after pancreatoduodenectomy for cancer
No full textObjective Complication rates after pancreatic resections remain high despite improvement in perioperative management. The effects of body composition and the relationship among different body compartments on surgical morbidity are not comprehensively investigated. The aim of this study was to assess whether the evaluation of different body compartments and their relationship was associated with the development of major postoperative complications after pancreatoduodenectomy (PD) for cancer. Methods We retrospectively analyzed 124 patients who underwent PD and had a staging computed tomography (CT) scan at our center. CT scan was used to measure abdominal skeletal muscle area and volume, as well as visceral fat area (VFA) and volume. The total abdominal muscle area (TAMA) was then normalized for height. The severity of complications was assessed. Univariate and multivariate analyses were performed to investigate correlations between the above variables and postoperative complications. The receiver operating characteristic curve methodology was used to investigate the predictive ability of each parameter. Results Major complications occurred in 42 patients (33.9%). The prevalence of sarcopenia was 24.2%. Regression analyses revealed no correlation between abdominal muscular and adipose tissue areas. Univariate analysis showed that the depletion of muscle area normalized for height was not per se predictive of complications (P = 0.318). Multivariate logistic regression showed that the VFA/TAMA was the only determinant of major complications (odds ratio, 3.20; 95% confidence interval, 1.35–7.60; P = 0.008). The model predictive performance was 0.735 (area under the curve) with a sensitivity of 64.3% and a specificity of 74.4%. Conclusion Sarcopenic obesity is a strong predictor of major complications after PD for cancer
MRONJ ASSOCIATED WITH DENTAL INFECTION AND SECONDARY INVOLVEMENT OF THE NEARBY IMPLANT: A CASE REPORT
No full textSince the first reports concerning osteonecrosis of the jaws there has been a lot of debate about the treatment modalities: therapy of the established pathology can in fact be medical or surgical and, in the latter case, be conservative or radical. The widespread difference of clinical presentations and relative rarity of advanced stages disease at diagnosis has not yet been able to guarantee a complete standardization in the therapeutic planning phase. Although there is a well-defined staging of the pathology, the international debate is still heated about more or less invasive surgical attitudes.
We collected data about ONJ in oncological patients surgically treated in our centre during the last 14 years: particular attention was paid to the variables and correlations between relapse, disease staging and treatment modalities. This is to underline the correlation between stage and type of treatment, as well as the greater possibility of relapse in the more advanced stages, in addition to its constancy in relation to the types of treatment. Finally, particular attention was paid to the timing of the relapse, generally located in the second semester of follow-up.
Our clinical cases presentation, although far from statistical significance, aims to generate attention especially on this last parameter, in order to improve outpatient follow-up procedures
On the thermo-mechanical behavior of NiTi shape memory elements for potential smart micro-actuation applications
No full textAmong smart and functional materials, the shape memory alloys are enabling the development of a new class of devices for the automotive, aerospace, biomedical, and mechanical applications based on the shape memory and superelastic effects. In this work, a study on the mechanical response of NiTi shape memory micro-elements, in the so-called “snake-like” configuration, is reported. These elements were patterned by means of laser micro-processing from thin NiTi sheets and then chemically etched. Different micro-elements, as function of the number of the curvatures replicated, were fabricated and tested. The functional performances of the micro-elements were characterized through calorimetric analysis for the definition of the operating temperatures and through thermo-mechanical testing for the evaluation of their actuating response. Mechanical tests were carried out to assess the tensile behavior of martensite and austenite phases separately, and for evaluating the thermal hysteresis under different constant loads during cooling/heating loops. Moreover, finite element modeling was also accomplished to analyze the stress distribution in both the martensitic and austenitic phases as loading
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