718 research outputs found
Effect of Sugars on Gelation Kinetics of Gelatin Gels
We investigate the rheological behavior of aqueous solutions containing animal gelatin, sugars and polyols. The aim is to study how the gelation kinetics, transition temperatures and gel strengths of an aqueous gelatin solution can be affected by the progressive addition of co-solutes. Aqueous solutions with a fixed mass percentage of gelatin of 6.8 wt% were prepared at various concentrations of sugars and polyols. Through Dynamic Temperature Ramp tests, performed at various ramp rates, and Dynamic Time Sweep and Dynamic Frequency Sweep tests, carried out at different temperatures, it was possible both to evaluate the transition temperatures and to monitor the gelation kinetics of the samples. It was found that the contribution of co-solutes positively affects both the gelation process and the thermal stability of the aqueous gelatin solution by reducing the gelation time and improving the mechanical properties of the gel in terms of network elasticity
VALUTAZIONE DEL CALCIO INTRACELLULARE IN PIASTINE DI CANI SANI ED AFFETTI DA LEISHMANIOSI
Le piastrine rappresentano gli elementi cellulari fondamentali per il processo di regolazione dell’emostasi. La loro
interazione con l’endotelio vasale riveste un ruolo fondamentale sia nella fisiologia che nella fisiopatologia della
coagulazione. fisiologicamente, infatti, le piastrine hanno la capacitĂ di aderire alla parete del vaso solo dopo attivazione
da parte dell’endotelio vasale. In condizioni patologiche, come quelle causate dalla rottura di una placca aterosclerotica,
le piastrine aderiscono all’endotelio, si attivano e reclutano numerose altre piastrine per la formazione del tappo
piastrinico. In medicina veterinaria, diversamente dalla medicina umana, la conoscenza dei meccanismi fisiologici
specifici alla base di tali processi è piuttosto scarsa. Le piastrine subiscono fenomeni di attivazione, fra i quali è possibile
menzionare, lo shape change, l’attivazione del recettore per il fibrinogeno che causa l’aggregazione delle piastrine, il
rilascio del contenuto dei granuli e la produzione di trombossano A2 (Gachet C. et al., 1996, Mills D.C.B., 1996). Tali
fenomeni sono mediati da modificazioni del calcio intracellulare che origina dal rilascio di calcio dagli store intracellulari
e dall’entrata di calcio dal mezzo extracellulare (Rink T.J. et al., 1985, Rink T.J. et al., 1990). D’altro canto però, sono
note numerose patologie nel cane, tra cui forme di Leishmaniosi eo Ehrlichiosi, che comportano seria compromissione
della funzione coagulativa (Harrus S. et al., 1996; Weiss D.J. et al., 1995). La leishmaniosi, in particolare, è una zoonosi
largamente diffusa nelle zone costiere del Mediterraneo caratterizzata da una alterazione della coagulazione spesso
asintomatica che si inserisce in un quadro sintomatologico estremamente vario. In precedenti ricerche abbiamo mostrato
che, in corso di leishmaniosi, si verifica un danno piastrinico di entitĂ variabile che, peraltro, non trova completa
risoluzione con le terapie normalmente utilizzate in corso di tale patologia. I meccanismi attraverso i quali l’aggregazione
piastrinica risulta alterata in corso di leishmaniosi non sono ancora chiari. Per tale motivo, l’obiettivo di questo studio è
stato quello di valutare le variazioni di calcio nelle piastrine di cani sani ed affetti da leishmaniosi allo scopo di
raggiungere una migliore comprensione dei meccanismi responsabili di alterazioni dell’emostasi in corso di tale
patologia
Ofd1 Controls Dorso-Ventral Patterning and Axoneme Elongation during Embryonic Brain Development.
Oral-facial-digital type I syndrome (OFDI) is a human X-linked dominant-male-lethal developmental disorder caused by mutations in the OFD1 gene. Similar to other inherited disorders associated to ciliary dysfunction OFD type I patients display neurological abnormalities. We characterized the neuronal phenotype that results from Ofd1 inactivation in early phases of mouse embryonic development and at post-natal stages. We determined that Ofd1 plays a crucial role in forebrain development, and in particular, in the control of dorso-ventral patterning and early corticogenesis. We observed abnormal activation of Sonic hedgehog (Shh), a major pathway modulating brain development. Ultrastructural studies demonstrated that early Ofd1 inactivation results in the absence of ciliary axonemes despite the presence of mature basal bodies that are correctly orientated and docked. Ofd1 inducible-mediated inactivation at birth does not affect ciliogenesis in the cortex, suggesting a developmental stage-dependent role for a basal body protein in ciliogenesis. Moreover, we showed defects in cytoskeletal organization and apical-basal polarity in Ofd1 mutant embryos, most likely due to lack of ciliary axonemes. Thus, the present study identifies Ofd1 as a developmental disease gene that is critical for forebrain development and ciliogenesis in embryonic life, and indicates that Ofd1 functions after docking and before elaboration of the axoneme in vivo
Role of polymeric coating on metallic foams to control the aeroacoustic noise reduction of airfoils with permeable trailing edges
Studies on porous trailing edges, manufactured with open-cell Ni-Cr-Al foams with sub-millimeter pore sizes, have shown encouraging results for the mitigation of turbulent boundary-layer trailing-edge noise. However, the achieved noise mitigation is typically dependent upon the pore geometry, which is fixed after manufacturing. In this study, a step to control the aeroacoustics effect of such porous trailing edges is taken, by applying a polymeric coating onto the internal foam structure. Using this method, the internal topology of the foam is maintained, but its permeability is significantly affected. This study opens a new possibility of aeroacoustic control, since the polymeric coatings are temperature responsive, and their thickness can be controlled inside the foam. Porous metallic foams with pore sizes of 580, 800, and 1200 ÎĽm are (internally) spray-coated with an elastomeric coating. The uncoated and coated foams are characterized in terms of reduced porosity, average coating thickness and air-flow resistance. Subsequently, the coated and uncoated foams are employed to construct tapered inserts installed at the trailing edge of an NACA 0018 airfoil. The noise mitigation performances of the coated metal foams are compared to those of uncoated metal foams with either similar pore size or permeability value, and both are compared to the solid trailing edge reference case. Results show that that the permeability of the foam can be easily altered by the application of an internal coating on the metallic foams. The noise reduction characteristics of the coated foams are similar to equivalent ones with metallic materials, provided that the coating material is rigid enough not to plastically deform under flow conditions
DIMENSIONLESS PHYSICAL-MATHEMATICAL MODELING OF TURBULENT NATURAL CONVECTION
Natural convection heat transfer is present in the most diverse applications of Thermal Engineering, such as in electronic equipment, transmission lines, cooling coils, biological systems, etc. The correct physical-mathematical modeling of this phenomenon is crucial in the applied understanding of its fundamentals and the design of thermal systems and related technologies. Dimensionless analyses can be applied in the study of flows to reduce geometric and experimental dependence and facilitate the modeling process and understanding of the main influence physical parameters; besides being used in creating models and prototypes. This work presents a methodology for dimensionless physical-mathematical modeling of natural convection turbulent flows over isothermal plates, located in an “infinite” open environment. A consolidated dimensionless physical-mathematical model was defined for the studied problem situation. The physical influence of the dimensionless numbers of Grashof, Prandtl, and Turbulent Prandtl was demonstrated. The use of the Theory of Dimensional Analysis and Similarity and its application as a tool and numerical device in the process of building and simplifying CFD simulations were discussed
Il Sistema Informativo Territoriale della Rete Integrata Nazionale GPS (RING)
Since 2004, an important technological infrastructure has been created in Italy by INGV in order to investigate active tectonics targets. A Continuous GPS network constituted by about 130 stations has been deployed all over Italy. The development and the realization of a stable GPS monumentation, the integration with other classical seismological instruments and the choice of both satellite and internet data transmission make this network one of the most innovative and reliable CGPS networks in the world. The development of the CGPS network has been accompanied by a technologically advanced development of all the aspects related to the data acquisition and the data information mining: a database and a SIT. Based on the recent techniques of Knowledge Management, the database has been developed to manage the data and the data information of all the sites of the RING network, thus allowing us to centralize information in a single common data bank and to create an unique service of access point to the data from different remote sites by internet connections. The SIT has been developed to be fully integrated with the Knowledge Management technology and it is aimed to synthesize and to display in a geographic interface the information of the RING sites. This work has been integrated with all other spatial data, such as topographic and geo-thematic maps, geological, seismological and seismo-tectonic databases. In this work, the technological aspects of the SIT of the RING network will be detailed and some examples of thematic maps will be shown
Objective Knowledge Mediates the Relationship between the Use of Social Media and COVID-19-Related False Memories
The exposure to relevant social and/or historical events can increase the generation of false memories (FMs). The Coronavirus Disease 2019 (COVID-19) pandemic is a calamity challenging health, political, and journalistic bodies, with media generating confusion that has facilitated the spread of fake news. In this respect, our study aims at investigating the relationships between memories (true memories, TMs vs. FMs) for COVID-19-related news and different individual variables (i.e., use of traditional and social media, COVID-19 perceived and objective knowledge, fear of the disease, depression and anxiety symptoms, reasoning skills, and coping mechanisms). One hundred and seventy-one university students (131 females) were surveyed. Overall, our results suggested that depression and anxiety symptoms, reasoning skills, and coping mechanisms did not affect the formation of FMs. Conversely, the fear of loved ones contracting the infection was found to be negatively associated with FMs. This finding might be due to an empathy/prosociality-based positive bias boosting memory abilities, also explained by the young age of participants. Furthermore, objective knowledge (i) predicted an increase in TMs and decrease in FMs and (ii) significantly mediated the relationships between the use of social media and development of both TMs and FMs. In particular, higher levels of objective knowledge strengthened the formation of TMs and decreased the development of FMs following use of social media. These results may lead to reconsidering the idea of social media as the main source of fake news. This claim is further supported by either the lack of substantial differences between the use of traditional and social media among participants reporting FMs or the positive association between use of social media and levels of objective knowledge. The knowledge about the topic rather than the type of source would make a difference in the process of memory formation
Oxaliplatin plus irinotecan and leucovorin-modulated5-fluorouracil triplet regimen every other week:a dose-finding study in patients with advanced gastrointestinal malignancies
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Validation of High-Fidelity Numerical Simulations of Acoustic Liners Under Grazing Flow
High-fidelity numerical simulations with the lattice-Boltzmann method are carried out to characterize the response of an acoustic liner in the presence and in the absence of grazing flow. The liner’s impedance is numerically computed with different methods, i.e. in-situ, mode matching and Prony-like Kumaresan-Tufts, and the results are compared against experimental data, measured in the Federal University of Santa Catarina (UFSC) liner test rig, and the Goodrich semiempirical model. The no-flow results show a reasonable agreement with the semiempirical model but some differences with respect to the experimental educed results are present. It is found that, even in the absence of grazing flow, when applying the in-situ method, there are large variations of the local impedance depending on the sampling location on the face sheet. In presence of grazing flow, simulations with acoustic plane wave propagating in the same direction and in the direction opposite to the mean flow are carried out. Results show that, with the current grid resolution, the numerical educed impedance still overestimates the experimental one particularly at low frequencies, while better agreement is obtained with the in-situ numerical estimation, for both cases. The effects of the grazing flow on the local impedance measurements show high influence of near-orifice wake development. A drastic reduction of the effective percentage of open area is observed when there is grazing flow, as a result of the formation of vortices in the orifices of the liner
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