1,157 research outputs found
Genomic variations in Saccharomyces cerevisiae populations: diffusion in vineyards and effect on vinification processes
No full textThe project of this doctoral thesis arisen from a previous work of vineyard yeast isolation, collection and characterization, which was held at the Wine Microbiology laboratory of the University of Padova in Conegliano (CIRVE). Some genomic variations have been uncovered thanks to the genome sequencing of four S. cerevisiae strains. The relationship between the yeast genotype and phenotype is one of the most debated topics in wine microbiology. Aimed to trying deepening the knowledge regarding the genomic variations effects on the oenological performances of wine yeasts, this thesis is focused on the diffusion of some genomic variations in vineyard yeasts populations and on their implications on the strains technological phenotype.
The oenological characterization of Brazilian Saccharomyces cerevisiae yeast strains has been performed, paying attention to the link between the local agricultural practices and the strains biodiversity in vineyard. Results showed that the heavy use of Cu in plant protection contributed to develop a strong Cu tolerance in the autochthonous population. This effect didn’t affect the strains genotype biodiversity so those vineyards were confirmed as great reservoir for wine yeast strains isolation and selection.
The strains Cu and SO2 tolerance has been studied on Italian and Brazilian S. cerevisiae vineyard strains. The studied topics were the relationship between the CUP1 Copy N° Variation and the Cu tolerance and the relationship between the presence of two chromosomal translocations and the SO2 tolerance. Results evidenced an association between genetic traits and tolerant phenotypes at vineyard population level, in particular for Cu tolerance and the CUP1 CNV. Moreover, hints of an association between Cu and SO2 tolerance are discussed.
The fermentable carbon sources uptake in 4 S. cerevisiae strains has been investigated. The expression of the hexose transporters genes has been analysed during stationary phase of synthetic must fermentation. The study involved FSY1, found in EC1118 and encoding for a high affinity fructose/H+ symporter, present in the 25% of the vineyard strains. Gene expression analysis evidenced that strain-specificity is not related to a single gene but it depends on the main regulation pathways. The higher utilization of FSY1 by P301.9 and R31.3 seems counterbalancing their higher glucose preference during fermentation. The FSY1 putative role in wine yeast seems to be its acting as helper of more effective carbon sources utilization at the latest fermentation stages. This work can contribute in improving the wine yeasts characterization by giving a tool for their distinction for fitness in the winemaking environment, at transcriptional level.
Lastly, S. cerevisiae strains EC1118 and QA23have been studied under the Martinotti’s method for sparkling wine production. The yeast cells viability during the pied-de-cuve preparation, the pressure evolution in autoclave and the cells response to the wine chilling at the end of the second fermentation were taken into account. During the wine chilling, cells have been recovered for the total RNA extraction to be used in transcriptomic analysis. Preliminary results show that EC1118 has been characterized by lower cells viability than QA23 since the ethanol adaptation procedure and all along the fermentative process. This difference reflected to the pressure evolution kinetic. Data of the total RNA extraction, quantification, integrity and quality check are also presented
Diffusion of FSY1 fructose transporter in a population of Saccharomyces cerevisiae isolated in vineyard and its effect on sugar conversion
No full textGiulia Veronica Varisco
No full textThe headword explains the biography and the contribution of the author Giulia Varisco to the children's literatur
Chemical and microbiological assessment of early wine fermentation phase can predict yeast cell viability during post-fermentation process
No full textThe management of post-fermentation phase is essential for the protection of wine oxidation. The prolonged contact of yeast lees and wine can help to limit this problem, although off-flavours can originate. It is known that some cellular components (mannoproteins, lipids, glutathione, etc.) released into the wine influence oxygen protection; however, still active cells could contribute to maintaining protection against oxidation. To date, in the literature there is a lack of data that evaluates cell viability, especially in the post-fermentation phase, particularly using methods different by plate count that identifies only a small part of the viable population. The aim of the work was to investigate the yeast viability of 12 wine Saccharomyces cerevisiae strains during 45 days after the fermentation in natural grape juice. The major fermentation parameters were measured at early phase (40 h) and at the end of the process, and were correlated with total and viable cells in the post-fermentation phase. Contrary to what has been observed in the literature, this work demonstrates that cell viability in the post-fermentation phase is very high and dependent on the yeast strain. A predictive model that can estimate viability in the post-fermentation phase, based on parameters measured at the early fermentation phase, was successfully set up. This approach can be adopted by wineries or winemakers as it uses fermentation data (sugar and nitrogen residues, ethanol and glycerol production, total cell count) obtained through simple chemical and microbiological analyses
The role of nitrogen uptake on colonization ability of vineyard Saccharomyces cerevisiae strains
No full textPolarization and long-run mobility: yearly wages comparison in three southern European countries
No full textWe explore the possible presence of polarization in the wage distribution
for Italy, Spain and Portugal, using both descriptive statistics and the Mover Stayer
model to evaluate its long-run behavior. We find that Italy and Spain are characterized
by an increasing polarization, mainly due to a rise in the percentage of part-time
workers, whereas Portugal maintains a unimodal wage’s distribution
Ytterbium Disilicate/Monosilicate Multilayer Environmental Barrier Coatings: Influence of Atmospheric Plasma Spray Parameters on Composition and Microstructure
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Ytterbium Disilicate/Monosilicate Multilayer Environmental Barrier Coatings: Influence of Atmospheric Plasma Spray Parameters on Composition and Microstructure
by Giulia Di Iorio,Laura Paglia *ORCID,Giulia PedrizzettiORCID,Virgilio GenovaORCID,Francesco MarraORCID,Cecilia BartuliORCID andGiovanni PulciORCID
INSTM Reference Laboratory for Materials and Surface Engineering, Sapienza University of Rome, Eudossiana 18, 00184 Rome, Italy
*
Author to whom correspondence should be addressed.
Coatings 2023, 13(9), 1602; https://doi.org/10.3390/coatings13091602
Original submission received: 10 August 2023 / Revised: 31 August 2023 / Accepted: 11 September 2023 / Published: 13 September 2023
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Abstract
SiC/SiC ceramic matrix composites (SiCf/SiC CMCs) are regarded as the new materials for the hot-section components of aircraft gas turbine engines, since they have one-third of the density of metallic superalloys, a higher temperature capability, good mechanical strength, and excellent thermal shock resistance. However, high-temperature water-vapor-rich combustion gases can induce severe surface recession phenomena in SiC/SiC leading to component failure. For this reason, it is necessary to design protective coatings, i.e., environmental barrier coatings (EBCs), able to protect the SiC/SiC surface in combustion environments. In the present work, ytterbium monosilicate (Yb2SiO5), stable when exposed to water vapor at high temperatures, and ytterbium disilicate (Yb2Si2O7), characterized by a thermal expansion coefficient closer to that of the substrate, were selected for a multilayer EBC system. EBCs were processed using the atmospheric plasma spray (APS) technique. A set of deposition parameters were tested, varying the power of the torch, and the composition and microstructure of the deposited coatings were studied in terms of porosity, crack density, and post-deposition phase retention by performing SEM, EDS, and XRD analysis. The results allow for the definition of the influence of deposition parameters on the final properties of multilayer EBC coatings
Correction to: Safety and Psychological Outcomes of Tandem t:Slim X2 Insulin Pump with Control-IQ Technology in Children, Adolescents, and Young Adults with Type 1 Diabetes: A Systematic Review
No full textThe second author name was incorrectly published as Giula Maria Smylie. The correct name is Giulia Marie Smylie. The original article has been corrected
Scrivere senza anestesia. La chiarezza di Giulia Niccolai
No full textIl saggio colloca storicamente la narratrice e poetessa Giulia Niccolai nel canone del Novecento letterario italiano discutendone poetica e cifre stilistiche. L'ampia analisi proposta tocca tutte le opere dell'autrice evidenziandone i legami intertestuali, anche tra poesia e narrativa, e i progressivi sviluppi in un arco cronologico esteso, tra anni Sessanta e primi anni Duemila. Lo studio coglie anche l'importanza dei riferimenti alle arti visive, in particolare alla fotografia, che Giulia Niccolai ha praticato in prima persona negli anni della Neoavanguardia, e alla pittura americana.The essay places the narrator and poet Giulia Niccolai in the canonical twentieth century Italian literary discussing her poetics and stylistic figures. The wide analysis proposed touches all the works of the author highlighting the intertextual links, also between poetry and narrative, and the progressive developments in an extended chronological period, between the Sixties and early Twenties. The study also captures the importance of references to the visual arts, especially photography, which Giulia Niccolai has practiced in the years of the Neo-avant-garde, and to American painting
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L'afrofuturismo tra Stati Uniti e Italia. Dalla memoria storica ai viaggi intergalattici per re-immaginare futuri postumani
No full textIn this article the author explores the cultural movement called Afrofuturism, tracing its origins, features, simbology, and its historical and political meanings. Starting from the (supposed) discoursive gap between African and African American people on one side and technology and science fiction on the other, this paradigm addresses themes related to the intersection of African Diaspora and African cultures with technology and science fiction, with the aim to recover the history of slavery and racism through the projections into alternative space-time contexts. In particular, the author explores the feminist afrofuturism perspective in order to examine the specific oppression and cultural production of African and African American women. In doing so, the author analyzes the development of afrofuturism in Italy, focusing on the work of the singer and beatmaker Karima 2G
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