Search results for "Modulation"

showing 10 items of 948 documents

New frontiers in regenerative medicine in cardiology: the potential of Wharton's jelly mesenchymal stem cells.

2013

Cardiomyopathies are still the first cause of death in the world. The identification of resident stem cells, comprising those derived from sub-endocardial stroma, suggests the possible self regeneration of the heart under autocrine/paracrine modulation in the cardiac microenvironment. Nevertheless, because of the limited in vivo regeneration potential of damaged cardiac tissue, the use of drugs and ultimately cardiac transplantation remain the common treatments of heart diseases and defects. The differentiative potential of embryonic and mesenchymal stem cells (MSCs) derived from different tissues (such as bone marrow and adipose tissue) was extensively explored in cell therapy for regenera…

Settore BIO/17 - IstologiaImmune modulationCardiologyMedicine (miscellaneous)Clinical uses of mesenchymal stem cellsHeart failureBiologyRegenerative MedicineRegenerative medicineWharton's jellyHumansWharton JellyTissue repairMesenchymal stem cellStem cell transplantation for articular cartilage repairSettore BIO/16 - Anatomia UmanaWharton's jellyRegeneration (biology)Mesenchymal stem cellMesenchymal Stem CellsGeneral MedicineHeart failure; Immune modulation; Mesenchymal stem cells; Regenerative medicine; Tissue repair; Wharton's jellyTransplantationCardiovascular DiseasesImmunologyCancer researchStem cell
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Umbilical Cord Mesenchymal Stromal Cells for Cartilage Regeneration Applications

2022

Chondropathies are increasing worldwide, but effective treatments are currently lacking. Mesenchymal stromal cell (MSCs) transplantation represents a promising approach to counteract the degenerative and inflammatory environment characterizing those pathologies, such as osteoarthritis (OA) and rheumatoid arthritis (RA). Umbilical cord- (UC-) MSCs gained increasing interest due to their multilineage differentiation potential, immunomodulatory, and anti-inflammatory properties as well as higher proliferation rates, abundant supply along with no risks for the donor compared to adult MSCs. In addition, UC-MSCs are physiologically adapted to survive in an ischemic and nutrient-poor environment a…

Settore BIO/17 - IstologiaReview ArticleCell Biologymesenchymal stromal cells stem cells cartilage regenerative medicien tissue engineering immune modulationMolecular BiologyInternal medicineRC31-1245Stem Cells International
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Mesenchymal Stromal cells from Wharton's jelly (MSCs): coupling their hidden differentiative program to their frank immunomodulatory phenotype.

2018

No abstract

Settore BIO/17 - IstologiaWharton's jelly mesenchymal stromal cells differentiation immunomodulation umbilical cord stem cells
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The Immunomodulatory Features of Mesenchymal Stromal Cells Derived from Wharton’s Jelly, Amniotic Membrane, and Chorionic Villi In Vitro and In Vivo …

2016

This chapter focuses on the immunomodulatory properties of placental mesenchymal stromal cells (MSCs) derived from the amniotic membrane, umbilical cord, and chorionic villi. Within the amniotic membrane (AM), we discuss the immunomodulatory properties of the two main cell populations that can be isolated from AM: human amniotic mesenchymal stromal cells (hAMSCs) and human amniotic epithelial cells (hAECs). Within the umbilical cord, several compartments have been described, including the amniotic compartment, the Wharton’s jelly (WJ) compartment, and the vascular and perivascular compartment, but herein attention is focused on the properties of human WJ MSCs (hWJMSCs). Since different isol…

Settore BIO/17 - IstologiaWharton’s JellyUmbilical cord Wharton's jelly placenta mesenchymal stromal cells stem cells chorionic villi amniotic membrane regenerative medicine differentiation immeune modulationSettore BIO/16 - Anatomia UmanaSettore BIO/13 - BIOLOGIA APPLICATA
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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Performance of LoRa technology: link-level and cell-level performance

2020

Abstract LoRa is a chirp spread spectrum technology that is becoming very popular for low-power wide-area networks, with high-density devices. In this chapter, we study the capacity of LoRa in rejecting different interfering signals. First, we analyze LoRa modulation numerically demonstrating that channel captures appear easily and that collisions between packets modulated with different spreading factors (SFs) are not uncommon. We validate such findings in experiments based on commercial devices and software-defined radios. Second, we model the network capacity obtainable in a typical LoRa cell: we show that high SFs can be seriously influenced by inter-SF collisions and that fading has a …

Settore ING-INF/03 - Telecomunicazionibusiness.industryComputer scienceNetwork packetLoRa IoTspreading factorinterferencecapacityperformanceChirp spread spectrumCellular levelModulationDefault gatewayLink levelFadingbusinessCommunication channelComputer network
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Investigation on Cascode Devices for High Frequency Electrical Drives Applications

2019

In the last years a widespread development in the market of electrical drives employing high-speed electrical machines has occurred in various industrial fields, due to the extremely high power density that can be reached. Nevertheless, to maintain output power quality without using bulky filtering networks, DC-AC converters should be controlled by means of higher PWM switching frequencies. New switching device technologies, such as Field Effect Transistors based on SiC and GaN, are therefore gathering momentum in order to comply with the higher working frequencies. To operate under high frequencies and at the same time at high voltage levels, alternative circuital configurations for switch…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniMomentum (technical analysis)High voltage deviceComputer sciencebusiness.industry020209 energyCascode020208 electrical & electronic engineeringElectrical engineeringHigh voltage02 engineering and technologyConvertersSettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciHigh frequencyPower transistors0202 electrical engineering electronic engineering information engineeringField-effect transistorPower semiconductor deviceCascodebusinessFrequency modulationPulse-width modulation
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Numerical study of the Kadomtsev–Petviashvili equation and dispersive shock waves

2018

A detailed numerical study of the long time behaviour of dispersive shock waves in solutions to the Kadomtsev-Petviashvili (KP) I equation is presented. It is shown that modulated lump solutions emerge from the dispersive shock waves. For the description of dispersive shock waves, Whitham modulation equations for KP are obtained. It is shown that the modulation equations near the soliton line are hyperbolic for the KPII equation while they are elliptic for the KPI equation leading to a focusing effect and the formation of lumps. Such a behaviour is similar to the appearance of breathers for the focusing nonlinear Schrodinger equation in the semiclassical limit.

Shock waveBreatherGeneral MathematicsGeneral Physics and AstronomySemiclassical physicsFOS: Physical sciencesPattern Formation and Solitons (nlin.PS)Kadomtsev–Petviashvili equation01 natural sciences010305 fluids & plasmassymbols.namesakeMathematics - Analysis of PDEs[ MATH.MATH-AP ] Mathematics [math]/Analysis of PDEs [math.AP]0103 physical sciencesModulation (music)FOS: Mathematics[MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]Mathematics - Numerical Analysis0101 mathematicsSettore MAT/07 - Fisica MatematicaNonlinear Schrödinger equationNonlinear Sciences::Pattern Formation and SolitonsLine (formation)PhysicsKadomtsev-Petviashvili equationKadomtsev Petviashvili equatuonNonlinear Sciences - Exactly Solvable and Integrable SystemsDispersive Shock waves010102 general mathematicsGeneral EngineeringNumerical Analysis (math.NA)Dispersive shock waves[ MATH.MATH-NA ] Mathematics [math]/Numerical Analysis [math.NA]Whitham equationsNonlinear Sciences - Pattern Formation and SolitonsLumpsKadomtsev Petviashvili equation dispersive shock wavesClassical mechanicsNonlinear Sciences::Exactly Solvable and Integrable SystemssymbolsSolitonExactly Solvable and Integrable Systems (nlin.SI)[MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]Kadomtsev Petviashvili equationAnalysis of PDEs (math.AP)
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Simple guidelines to predict self-phase modulation patterns

2018

International audience; We present a simple approach to predict the main features of optical spectra affected by self-phase modulation (SPM), which is based on regarding the spectrum modification as an interference effect. A two-wave interference model is found sufficient to describe the SPM-broadened spectra of initially transform-limited or up-chirped pulses, whereas a third wave should be included in the model for initially down-chirped pulses. Simple analytical formulae are derived, which accurately predict the positions of the outermost peaks of the spectra.

Shock wavePhysics[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics]FOS: Physical sciencesStatistical and Nonlinear Physics02 engineering and technologyInterference (wave propagation)01 natural sciencesAtomic and Molecular Physics and OpticsSpectral lineComputational physics010309 optics020210 optoelectronics & photonicsFiber Bragg gratingSimple (abstract algebra)0103 physical sciencesModulation (music)0202 electrical engineering electronic engineering information engineeringSelf-phase modulationFrequency modulationOptics (physics.optics)Physics - Optics
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A New Model for Sigma-Delta Modulator Oriented to Digitally Controlled DC/DC Converter

2007

Recent research activities have shown the feasibility and advantages of using digital controller ICs specifically developed for high-frequency switching converters, highlighting a challenging future trend in Switched-mode power supplies (SMPS) applications. Up to a few years ago, the application of digital control for SMPS was impractical due to the high cost and low performance of DSP and microcontroller systems, even if the advantages that digital controllers offer were well known, such as immunity to analog component variations and ability to implement sophisticated control schemes and system diagnostics. Digital controller ICs potentially offer other advantages from the integrated desig…

Sigma-delta modulatorEngineeringAdaptive controlbusiness.industryBuck converterHardware description languageDelta-sigma modulationSettore ING-INF/01 - Elettronicadigital controlDC/DC converterHardware and ArchitectureMechanics of MaterialsModeling and SimulationVHDLElectronic engineeringDigital controlElectrical and Electronic EngineeringbusinessField-programmable gate arraycomputerSoftwareDigital signal processingcomputer.programming_languageInternational Journal of Modelling and Simulation
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