1,721,074 research outputs found
Il GM-CSF può promuovere il differenziamento di monociti umani in cellule dendritiche dotate di distinte proprietà immuno-stimolatorie e migratorie: ruolo dell'espressione del recettore del GM-CSF
Full text linkLe cellule dendritiche mieloidi (DCs) e i macrofagi evolvono da un precursore comune. Comunque, è ancora poco chiaro quale siano i fattori che controllano il differenziamento dei monociti in DC o macrofagi. Noi abbiamo riportato che la densità di superficie della subunità α del recettore del GM-CSF (GM-CSFR) in monociti del sangue periferico umano varia tra i diversi donatori. Sebbene poi nessuna correlazione sia stata trovata tra l’entità di espressione del GM-CSFR e la capacità di monociti di differenziare in DC in presenza di GM-CSF e IL-4, l’espressione del GM-CSFR è stata vista però influenzare fortemente la generazione di cellule CD1a+ DC-like in assenza di IL-4. Le cellule CD1a+ generate in presenza del solo GM-CSF sono risultate esprimere le molecole CD40, CD80, MHC I and II, DC-SIGN, MR, CCR5 e mantenere in modo parziale il CD14. Queste stesse cellule sono state anche trovate capaci di indurre spontaneamente l’espansione di linfociti T CD4+ and CD8+ allogenici rilascianti IFN-gamma, e migrare in risposta alla CCL4 e alla CCL19. Dopo stimolazione con vari ligandi dei TLR, infine, esse sono state trovate acquisire caratteristiche fenotipiche di DC mature. La loro capacità allostimolatoria, invece, non è risultata ulteriormente incrementare a causa della produzione endogena di IL-10. Infatti, una più alta risposta proliferativa di cellule T e produzione di IL-12 da parte delle stesse DC-like attivate è stata osservata solo in seguito al blocco dell’IL-10 endogena indotta da LPS. Al contrario, l’IL-10 endogena non è stata vista avere effetti sulla secrezione di IL-23. Questi risulatati sottolineano l’importanza dell’espressione del GM-CSFR in monociti per la generazione di DC indotta da citochine e guardano al GM-CSF come ad un diretto protagonista nella generazione di DC funzionalmente distinte.Myeloid dendritic cells (DCs) and macrophages evolve from a common precursor. However, factors controlling monocyte differentiation toward DC or macrophage are poorly defined. We report that surface density of GM-CSF receptor (GM-CSFR) α subunit in human peripheral blood monocytes varies among donors. Although no correlation was found between the extent of GM-CSFR and monocyte differentiation into DC driven by GM-CSF and IL-4, GM-CSFR expression strongly influenced the generation of CD1a+ dendritic-like cells in the absence of IL-4. CD1a+ cells generated in the presence of GM-CSF express CD40, CD80, MHC I and II, DC-SIGN, MR, CCR5, and partially retain CD14 expression. Interestingly, they spontaneously induce the expansion of CD4+ and CD8+ allogeneic T lymphocytes producing IFN-gamma, and migrate toward CCL4 and CCL19. Upon stimulation with TLR ligands, they acquire the phenotypic features of mature DCs. In contrast, the allostimulatory capacity is not further increased upon LPS activation. However, by blocking LPS-induced IL-10, a higher T cell proliferative response and IL-12 production was observed. Interestingly, IL-23 secretion was not affected by endogenous IL-10. These results highlight the importance of GM-CSFR expression in monocytes for cytokine-induced DC generation and point to GM-CSF as a direct player in the generation of functionally distinct DCs
A hydraulic cylinder with variable power configuration: Design and validation of the fluid-dynamic model
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Hybrid Propulsion in SI Engines for New Generation Motorcycles: A Numerical-Experimental Approach to Assess Power Requirements and Emission Performance
No full textHybrid Electric Aircraft Model Based on ECMS Control
No full textThe hybrid-electric propulsion control system plays a fundamental role to ensure the correct function of all components and to operate a performing energy management. Several control strategies have been proposed in the literature, but the challenge is to keep these techniques methodologically simple and easy to implement. In this paper, an analytical derivation of the Equivalent Consumption Minimization Strategy (ECMS) for energy management of hybrid-electric aircraft is presented, based on Pontryagin’s Minimum Principle (PMP). Simulation results obtained for a parallel hybrid electric configuration with a maximum take-off power of 134 kW are also presented
Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions
No full textAmong the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions
A comparative assessment of hybrid parallel, series, and full-electric propulsion systems for aircraft application
Full text linkThis article presents a preliminary suitable sizing methodology for the design process of the powertrain architecture for a hybrid-electric propulsion system for ultra-light and general aviation aircraft. The main objective of this activity is to design and realize a prototype of a hybrid-electric propulsion system for Cessna 337 aircraft with a maximum take-off power of 134 kW. At the same mission, two operating strategies have been chosen, max recharge and max efficiency. Where, in the first case the engine runs at wide-open throttle to quickly charge the battery, while for the second run at minimum specific consumption to reduce consumption. The primary energy assessment has been conducted in all proposed propulsion configurations with the same aircraft, mission, and maximum take-off weight. The results also indicated that parallel hybrid propulsion shows a better compromise in terms of 10% energy saving, 4% CO2 reduction, and mission duration
Hybrid Propulsion for Motorcycle Application to Reduce Engine-out Emissions: An Analytical-Experimental Investigation
No full textAll over the world, motorcycles represent an important share of motorized vehicles helping to meet daily urban transport needs, thus, particularly in urban contexts, two-wheelers impact to air pollution is significant. In a previous experimental investigation, emissions of regulated pollutants were measured in the exhaust of a four-stroke motorcycle belonging to the Euro-3 legislative category. Since exhaust emissions and fuel consumption are very sensitive to variations in vehicles instantaneous speed and acceleration, such experimental results are used in this research to recognize the kinematic parameters that cause higher CO and HC emissions. The hybrid electric propulsion is then proposed to reduce exhaust emissions in particular driving conditions which include high levels of acceleration with resultant sudden steep increase in engine speed. In such phases, in fact, an enrichment of the air/fuel mixture is needed which affects the catalyst conversion efficiency. Subsequently, the power requirements and the grade of electrical assistance in such driving situations are estimated by a procedure based on both the measured exhaust emissions and the kinematic parameters that characterize the driving dynamics collected during the experimental tests. Finally, the share of CO and HC emissions that could be saved utilizing a hybrid motorcycle instead of a conventional thermal motorcycle is calculated through an environmental analysis
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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