Search results for "PLL"
showing 10 items of 62 documents
Tuning of biodegradation rate of PLLA scaffolds via blending with PLA
2009
Blends of Poly-L-Lactic Acid (PLLA) with Poly-Lactic Acid (PLA) in different proportions (95/5, 90/10, 80/20, 70/30 and 60/40) were utilized in order to realize biodegradable and biocompatible scaffolds for soft tissue engineering applications. The scaffolds were produced via thermally induced phase separation (TIPS) starting from ternary systems where dioxane was the solvent and water the non-solvent. Morphology was evaluated by Scanning Electron Microscopy (average pore size and interconnection). Foams’ apparent density was also evaluated (porosity ranges from 87% to 92%). Moreover an in vitro biodegradation test of scaffolds was set-up in order to verify the rate of degradation of the va…
Polymeric scaffolds based on blends of poly-l-lactic acid (PLLA) with poly-d-l- lactic acid (PLA) prepared via thermally induced phase separation (TI…
2012
Porous scaffolds based on blends of high crystalline Poly-L-lactic acid (PLLA) with low crystalline poly-D-L-lactic acid (PLA) were prepared via Ther- mally Induced Phase Separation (TIPS), with the aim of exploring the possibility to control the degradation behaviour of the PLA-based scaffold, simultaneously pre- serving the morphological characteristics required for tissue engineering applica- tions. Porous foams with different PLLA/PLA weight ratios (from 95/5 to 60/40) were produced and characterised in terms of pore size, porosity, and thermal properties. The scaffolds present an open porosity, with average pore sizes ranging from 30 to 70 lm. Results showed that, when dealing with a P…
IN-HOSPITAL COMPLICATIONS OF ACUTE MYOCARDIAL INFARCTION IN HYPERTENSIVE SUBJECTS
2005
BACKGROUND: Recent studies have shown a worse in-hospital outcome in hypertensive than in normotensive patients with acute myocardial infarction (AMI), which has been attributed to more frequent complications. The aim of this study was to investigate clinical patterns, risk factors, and in-hospital complications in hypertensive and normotensive patients with AMI. METHODS: Of 4994 consecutive patients with AMI admitted to the intensive care unit, hypertensive patients with first infarction (n = 915; mean age 68.8 +/- 11.4 years) and 915 gender- and age-matched normotensive subjects were retrospectively studied. RESULTS: In the univariate analysis, hypertensive subjects presented more frequen…
PLLA Scaffold via TIPS for Bone Tissue Engineering
2016
Tissue engineering offers a promising new approach to repair bone fractures, fractures that do not heal, and fractures due to bone tumors. In this work, two different approaches were tested in order to obtain Poly-L- Lactic Acid (PLLA) porous scaffolds via Thermally Induced Phase Separation (TIPS) for bone tissue engineering application. First, the possibility to produce a composite material, by incorporating Hydroxyapatite (HA) particles in a Poly-L-lactic acid (PLLA) matrix was investigated. Two PLLA/HA weight ratios (70/30 and 50/50) were tested. The results showed that the presence of HA does not influence the phase separation process, i.e. the composite scaffolds microstructure is simi…
Computation of lock-in range for classic PLL with lead-lag filter and impulse signals
2016
For a classic PLL with square waveform signals and lead-lag filter for all possible parameters lock-in range is computed and corresponding diagrams are given. peerReviewed
Non-linear analysis of a modified QPSK Costas loop
2019
A Costas loop is one of the classical phase-locked loop based circuits, which demodulates data and recovers carrier from the input signal. The Costas loop is essentially a nonlinear control system and its nonlinear analysis is a challenging task. In this article for a modified QPSK Costas loop we analyze the hold-in, pull-in and lock-in ranges. New procedure for estimation of the lock-in range is considered and compared with previously known approach. peerReviewed
A Continuous Pore Size Gradient PLLA Scaffold For Osteochondral Regeneration
2016
Osteochondral (OC) scaffold-based regenerative approaches in the joint are challenging since the scaffold must provide mechanical strength while also mimicking the local cartilage and bone microenvironments. Thermally Induced Phase Separation (TIPS) can produce scaffolds with a wide range of pore size morphologies/distributions. Here, we produced by TIPS a poly-L-lactide (PLL A) scaffold with a continuous pore size gradient along the sample thickness, from ~70μm diameter on one side to ~200 μm diameter on the opposite surface.
A software receiver adaptive phase lock loop method
2009
The aim of this paper is to introduce a new and relatively simple algorithm which is capable to tune the parameters of the loop filter in a phase lock loop, like the one that can be found in a global navigation satellite system receiver. The parameters are chosen while the system is running, in order to make the bandwidth of the filter adaptive with respect to the signal dynamic and strength. A wider bandwidth is obtained to make the filter more reactive when searching the carrier, while the bandwidth gets narrower when the system is in the tracking state, in order to cut off as much noise as possible. The algorithm is based on the observation of the estimated variance of the phase lock loo…
Computation of the lock-in ranges of phase-locked loops with PI filter
2016
In the present work the lock-in range of PLL-based circuits with proportionallyintegrating filter and sinusoidal phase-detector characteristics are studied. Considered circuits have sinusoidal phase detector characteristics. Analytical approach based on the methods of phase plane analysis is applied to estimate the lock-in ranges of the circuits under consideration. Obtained analytical results are compared with simulation results. peerReviewed
Síntesis de biodiésel y caracterización de bebidas alcohólicas mediante técnicas de elevada resolución
2015
En esta Tesis Doctoral se describe el desarrollo de procedimientos de síntesis de biodiésel y caracterización de bebidas alcohólicas mediante técnicas analíticas de elevada resolución. La puesta a punto de los procedimientos de síntesis de biodiésel y sus estudios de caracterización se realizó en respuesta a la demanda de producción de biocombustibles basados en materias primas renovables y de bajo impacto ambiental que puedan reemplazar de manera efectiva al diésel convencional obtenido a partir de fuentes fósiles. Otro de los aspectos descritos en esta Tesis, y entroncando con una de las líneas actuales de investigación del grupo, es la caracterización de proteínas en diversos extractos v…