65 research outputs found
Hybrid Metaheuristic Approach to Solve the Problem of Containers Reshuffling in an Inland Terminal
The paper deals with the problem of minimizing the reshuffling of containers in an inland intermodal terminal. The problem is tackled according to a hybrid approach that combines a preliminary selection of heuristics and a genetic algorithm. The heuristics are used to determine the initial population for the genetic algorithm, which aims to optimize the locations of the containers to store in the yard in order to minimize the operational costs. A simulation model computes the costs related to storage and pick-up operations in the yard bay. The proposed optimization method has been calibrated by selecting the optimal parameters of the genetic algorithm in a toy case and has been tested on a theoretical example of realistic size. Results highlighted that the use of a suitable heuristic to generate the initial population outperforms the genetic algorithm, initialized with a random solution, by 20%
Graphene decoupling through oxygen intercalation on Gr/Co and Gr/Co/Ir interfaces
We perform a density functional theory study of the effects of oxygen
adsorption on the structural and electronic properties of Gr/Co(0001) and
Gr/Co/Ir(111) interfaces. In both interfaces, the graphene-Co distance
increases with increasing O concentration. The oxygen intercalation effectively
decreases the electronic interaction, preventing the hybridization of graphene
states with Co -orbitals, hence (partly) restoring the typical Dirac cone of
pristine graphene. In the case of graphene/Co 1ML/Ir(111), which presents a
moir\'e pattern, the interplay between the O distribution and the continuous
change of the graphene-Co registry can be used to tune graphene corrugation and
electronic properties. The computed electronic properties are in very good
agreement with previously reported angle resolved photoemission spectroscopy
and photoemission electron microscopy measurements for Gr/Co(0001).Comment: 15 pages, 15 figure
Tungsten Oxide Nanowires Chemical Sensors
AbstractTungsten oxide nanowires have been synthetized by a simple thermal oxidation route in an oxygen atmosphere, at low vacuum pressure. The morphology of the nanostructures was investigated by scanning electron microscope (SEM).Chemical sensors were fabricated using tungsten oxide nanowires as active layer, directly deposited on the transducer. Gas sensingperformances were evaluated towards some target chemical species (CO, NO2, NH3, Acetone, Ethanol). Firstly, a temperature screening was performed in presence of a fixed gas concentration, to determine the optimal working temperature of the sensors. Then, calibration curves for some chemical species were estimated. The influence of relative humidity was taken into account. Fabricated devices seem very promising for the detection of ammonia and carbon monoxide
Finite Element Thermal Analysis of Metal Parts Additively Manufactured via Selective Laser Melting
In this chapter, a three-dimensional finite element model is developed to simulate the thermal behavior of the molten pool in selective laser melting (SLM) process. Laser-based additive manufacturing (AM) is a near net shape manufacturing process able to produce 3D objects. They are layer-wise built through selective melting of a metal powder bed. The necessary energy is provided by a laser source. The interaction between laser and material occurs within a few microseconds, hence the transient thermal behavior must be taken into account. A calibration procedure is carried out to fit the numerical solution with the experimental data. Once the calibration has corrected the thermal parameters, a dynamic mesh refinement is applied to reduce the computational cost. The scanning strategy adopted by the laser is simulated by a path simulator built using MatLab®, while numerical analysis is carried out using ANSYS®, a commercial finite element software. To improve the performance of the simulation, the two codes interact each other to solve the analysis. Temperature distribution and geometrical feature of the molten pool under different process conditions are investigated. Results from the FE analysis provide guidance for setting up the optimization of process parameters and develop a base for further residual stress analysis
Critical Review of the Pivotal Studies of Four rFVIII Products for the Treatment of Hemophilia A Patients: The Role of Octocog Alfa
INTRODUCTION: Hemophilia A is a rare congenital bleeding disorder caused by a deficiency of clotting factor VIII (FVIII). The severe form of the disease is characterized by spontaneous bleeds, especially into the joints. Prophylaxis, based on regularly intravenous administration of the missing factor to avoid hemorrhages, represents the gold standard of treatment. In recent years, new products that significantly improve the treatment management options for patients with hemophilia have become available in the market.OBJECTIVE: To critically evaluate the pivotal studies of recombinant FVIII (rFVIII) products, approved in Europe within the first half of 2018 having obtained the indication for a prophylaxis dosing regimen based also on a twice weekly infusion frequency or even less, highlighting their limitations or strengths.METHODS: A systematic literature search was conducted, and several databases (PubMed and Embase) were consulted.RESULTS: Nine clinical trials involving patients with severe hemophilia A without inhibitor were included in this analysis. Four rFVIII products (Elocta®, Biogen, Cambridge, MA, USA; Kovaltry®, Bayer HealthCare Pharmaceuticals, Germany; Afstyla®, CSL Behring GmbH, Germany; Adynovi®, Baxalta Innovation GmbH, Austria) with different pharmacokinetic profiles were evaluated. The trials included in this analysis had different designs and heterogeneous methods were utilized to assess the study outcomes. The baseline characteristics of the patients enrolled in the studies were also often different and sometimes not adequately described. LEOPOLD II, a trial to compare prophylaxis to on-demand therapy with an unmodified rFVIII product (Kovaltry®, octocog alfa), was the only completely randomized trial that enrolled a more critical patient population in terms of compromised joint condition than the other studies. Based on these side-by-side comparison, Octocog alfa reported similar efficacy, in terms of annualized bleeding rate, to the other rFVIII products, including extended half-life.CONCLUSIONS: Even without structural modifications, octocog alfa may be considered a useful treatment option for two times a week prophylaxis in a selected population of haemophilia patients
Effects of robotic guidance on the coordination of locomotion
Functional integration of motor activity patterns enables the production of coordinated
movements, such as walking. The activation of muscles by weightened summation of
activation signals has been demonstrated to represent the spatiotemporal components that
determine motor behavior during walking. Exoskeleton robotic devices are now often used in
the rehabilitation practice to assist physical therapy of individuals with neurological
disorders. These devices are used to promote motor recovery by providing guidance force to
the patients. The guidance should in principle lead to a muscle coordination similar to
physiological human walking. However, the influence of robotic devices on locomotor
patterns needs still to be characterized. The aim of this study was to analyze the effect of
force guidance and gait speed on the modular organization of walking in a group of eight
healthy subjects.This project is funded by the European Commission, project "BETTER" (contract number 247935) and Spanish Consolider-Ingenio Programme, project "HYPER" (contract number CSD2009-00067) and Universita Degli Studi di Roma "Foro Italico", research project "Dynamic sensorimotor interaction during locomotion: influences of perturbations and/or body unloading"
Solid state molecular rectifier based on self organized metalloproteins
Recently, great attention has been paid to the possibility of implementing
hybrid electronic devices exploiting the self-assembling properties of single
molecules. Impressive progress has been done in this field by using organic
molecules and macromolecules. However, the use of biomolecules is of great
interest because of their larger size (few nanometers) and of their intrinsic
functional properties. Here, we show that electron-transfer proteins, such as
the blue copper protein azurin (Az), can be used to fabricate biomolecular
electronic devices exploiting their intrinsic redox properties, self assembly
capability and surface charge distribution. The device implementation follows a
bottom-up approach in which the self assembled protein layer interconnects
nanoscale electrodes fabricated by electron beam lithography, and leads to
efficient rectifying behavior at room temperature.Comment: 13 pages including two figures. Accepted for publication in Advanced
Material
Cardiac injury and mortality in patients with Coronavirus disease 2019 (COVID-19): insights from a mediation analysis
Patients at greatest risk of severe clinical conditions from coronavirus disease 2019 (COVID-19) and death are elderly and comorbid patients. Increased levels of cardiac troponins identify patients with poor outcome. The present study aimed to describe the clinical characteristics and outcomes of a cohort of Italian inpatients, admitted to a medical COVID-19 Unit, and to investigate the relative role of cardiac injury on in-hospital mortality
Improving assessment and management of pain in hemophilia. An Italian Delphi consensus statement
: Comprehensive evidence-based guidelines and well-validated assessment scales for pain in people with hemophilia (PwH) are needed. Here, we report 28 statements covering five topics on pain assessment and management in pediatric and adult PwH that were developed by 60 Italian hemophilia specialists during a Delphi consensus process. Overall, a clear consensus was achieved for 19 of the 28 statements. Consensus was reached on all statements on the topic of pain assessment and quality of life (QoL), including the need for regular pain assessment on a quantitative scale, the importance of distinguishing between different pain types, and the need to evaluate the impact of pain on patient QoL. The other four topics concerned acute and chronic pain management in adults and in children. Consensus was reached on statements regarding non-pharmacologic treatment and the use of first-line paracetamol (acetaminophen). There was a lack of consensus regarding the use of non-steroidal anti-inflammatory drugs, cyclooxygenase-2 inhibitors, or opioids
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