Search results for "ingegneria"

Development of a novel in vitro system for biomedical applications

2022

Nella ricerca scientifica e medica, l'uso degli animali ha apportato notevoli benefici all’uomo. Sebbene la loro fisiologia non imiti perfettamente il corpo umano, essi agiscono come perfetti "modelli" per lo studio delle malattie umane e lo sviluppo di nuovi farmaci e trattamenti. Tuttavia, secondo la Food and Drug Administration (FDA), solo l'8% dei farmaci testati sugli animali è considerato sicuro ed efficace per l'uso sull’essere umano, il 92% non lo è. Questi tassi di fallimento estremamente elevati nello sviluppo di farmaci, insieme ai costi in forte aumento, hanno portato molti ricercatori a rivalutare il valore degli studi in vivo sugli animali. Questo è stato il motivo per cui, ne…

PLLA scaffolds with controlled architecture as potential microenvironment for in vitro tumor model

2019

Abstract The "microenvironment" where a tumor develops plays a fundamental role in determining its progression, the onset of metastasis and, eventually, its resistance to therapies. Tumor cells can be considered more or less invasive depending both on the nature of the cells and on the site where they are located. Commonly adopted laboratory culture protocols for the investigation of tumor cells take usually place on standard two-dimensional supports. However, such cultures do not allow for reproduction of the biophysical properties of the tumor’s microenvironment, thus causing the cells to lose most of their relevant characteristics. In this work MDA-MB 231 breast cancer cells were cultiva…

Firefly Algorithm for Structural Optimization Using ANSYS

2021

In the mid-1980s, several metaheuristic methods began to be developed for solving a very large class of computational problems with the aim of obtaining more robust and efficient procedures. Among them, many metaheuristic methods use bio-inspired intelligent algorithms. In recent years, these methods are becoming increasingly important and they can be used in various subject areas for solving complex problems. Firefly Algorithm is a nature-inspired optimization algorithm proposed by Yang to solve multimodal optimization problems. In particular, the method is inspired by the nature of fireflies to emit a light signal to attract other individuals of this species. In this work, a numerical stu…

Absorption kinetics and swelling stresses in hydrothermally aged epoxies investigated by photoelastic image analysis

2015

Abstract The present work proposes an experimental optical methodology able to measure the transient swelling stresses induced by the water uptake ageing of polymers. In particular, the work describes the implementation of a Photoelastic technique to quantify internal stresses arising during the hydrothermal ageing of cast epoxy samples. The material investigated is a model DGEBA/DDS epoxy system. Curing and post-curing cycles have been optimised in order to obtain a fully cured, high T g , and completely stress free initial condition. Rectangular beam samples were then left in a hydrothermal bath at 90 °C, and regularly monitored by gravimetric and photoelastic analyses. The quantitative e…

Nitrous oxide emission from a moving bed membrane biofilm reactor: the effect of the sludge retention time

2016

The aim of the present study was to investigate the nitrous oxide (N2O) emissions from a University of Cape Town (UCT) moving bed membrane bioreactor pilot plant. An experimental campaign was carried out during 60 days with three different sludge retention time (SRT). The pilot plant reactor was provided of funnel shape covers that guaranteed gas accumulation in the headspace. The results highlighted that N2O concentrations significantly increased when the biofilm concentrations increased within the aerobic and anoxic compartments. Furthermore, results have shown an increase of N2O with the decrease of SRT. Moreover, the MBR tank resulted the key emission source (up to 70% of the total N2O …

Aeration tank and secondary clarifier as one system. in "Activated Sludge Separation Problems: Theory, Control Measures, Practical Experieces. Eds. R…

2017

Traditionally the activated sludge process is treated as two stage process. The first stage (aeration basin) is described in terms of biological processes while the description of the second stage concentrates on processes of biomass separation and thickening. The modern approach to the activated sludge process looks at both the biological and the separation stage as one system. The aim of this chapter is to explain the interactions between the two parts of the activated sludge system.

Adaptive scheduling of acceleration and gyroscope for motion artifact cancelation in photoplethysmography

2022

Background and objective: Recently, various algorithms have been introduced using wrist-worn photo-plethysmography (PPG) to provide high accuracy of instantaneous heart rate (HR) estimation, including during high-intensity exercise. Most studies focus on using acceleration and/or gyroscope signals for the motion artifact (MA) reference, which attenuates or cancels out noise from the MA-corrupted PPG signals. We aim to open and pave the path to find an appropriate MA reference selection for MA cancelation in PPG.Methods: We investigated how the acceleration and gyroscope reference signals correlate with the MAs of the distorted PPG signals and derived both mathematically and experimentally a…

PROGETTAZIONE PER ADDITIVE MANUFACTURING DI ORTESI DI GOMITO PERSONALIZZATE E SVILUPPO DI MODELLO PARAMETRICO BASATO SU ALGORITMI GENERATIVI

Nonlinear coupling is absent in acute myocardial patients but not healthy subjects.

2008

We investigated whether autonomic nervous system imbalance imposed by pharmacological blockades and associated with acute myocardial infarction (AMI) is manifested as modifications of the nonlinear interactions in heart rate variability signal using a statistically based bispectrum method. The statistically based bispectrum method is an ideal approach for identifying nonlinear couplings in a system and overcomes the previous limitation of determining in an ad hoc way the presence of such interactions. Using the improved bispectrum method, we found significant nonlinear interactions in healthy young subjects, which were abolished by the administration of atropine but were still present afte…

Effect of aneurysm on the mechanical dissection properties of the human ascending thoracic aorta

2012

Objectives: The acute dissection of an ascending thoracic aortic aneurysm (ATAA) represents a devastating separation of elastic layers occurring when the hemodynamic loads on the diseased wall exceed the adhesive strength between layers. At present, the mechanics underlying aortic dissection are largely unclear, and the biomechanical delamination properties of the aneurysmal aorta are not defined. Individuals with bicuspid aortic valve (BAV) are particularly predisposed to ascending aortic aneurysm formation, with a marked risk of aortic dissection. The purpose of this study was to evaluate and compare the dissection properties of nonaneurysmal and aneurysmal human ascending thoracic aorta …