Browsing by Author "Vargas, Sebastián"

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    Influence of grape quality tier, harvest timing, and yeast strain on mannoprotein content, phenolic composition, and color modulation in young red wines
    (Elsevier Ltd, 2025) Galaz Torres, Cristian; Vidal Zuñiga, Josefina Victoria; Vargas, Sebastián; Zincker, Jorge; Brossard, Natalia; Bordeu, Edmundo; Ricci, Arianna; Parpinello, Giuseppina P.; Versari, Andrea
    Besides the impact of harvest timing and grape quality, this study investigated the performance of selected yeast strains overproducing mannoproteins versus the conventional strain AGL 804 in terms of mannoprotein release and its consequences on the composition and color modulation of short-aged commercial red wines. The study fills a gap of volume and actual red wine production by comparing 36 winemaking conditions, each of 850 kg of grapes. The results showed that AGL 804 produced the same or more concentration of mannoproteins than the alternatives. Then, an apparent threshold was found for all yeasts when the dissolved solids content of grape musts at harvest exceeded 22 °Bx, beyond which no increase in mannoprotein production was observed. Only below this limit, an independent effect of yeast strains on tannin concentration and tannin-to-anthocyanin ratio (T/A) in wines was observed. These two parameters exhibited a moderate correlation with mannoprotein concentration (R2 = 0.534 and R2 = 0.696, respectively), and a low-moderate correlation for mannoprotein concentration with CIELAB color parameters. Wines produced from grapes > 22 °Bx showed only harvest-related variations in tannin concentration and T/A and no correlation between parameters analyzed and mannoprotein production. The study revealed that, although yeast strains influence the color of red wine after six months of bottling, their effect is secondary to the harvest timing. Moreover, the influence of the yeast strain itself was not consistent across the different harvest dates. Additionally, the study provides winemakers with an improved and practical assay for measuring mannoprotein levels in red wines, especially for small winery laboratories. It also introduces a novel 3D graphical representation of the CIELAB color parameters, which simultaneously integrates the real visible color of the wines and its visual discriminability to the human eye.
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    Manejo de carcinomas queratinocíticos perioculares com cirurgia micrográfica de Mohs e preditores de reconstrução complexa: estudo retrospectivo
    (2024) Peirano, Dominga; Vargas, Sebastián; Hidalgo Acuña, Leonel Esteban; Donoso Mena, Francisca; Albuseme, Eugenia; Sanhueza Zamora, Felipe Alberto; Cardenas De La Torre, Consuelo Paz; Droppelmann Droppelmann, Katherine Ann; Castro, Juan Camilo; Uribe González, Pablo Francisco; Zoroquiain Vélez, José Pablo; Navarrete Dechent, Cristian Patricio
    Fundamentos: O câncer de pele é o tipo mais frequente em todo o mundo e o mais frequente tumor periocular. Os carcinomas queratinocíticos (CQ) localizados em áreas perioculares são considerados tumores de alto risco. A cirurgia micrográfica de Mohs (CMM) é considerada a primeira linha para o tratamento do CQ de alto risco, com menor taxa de recorrência do que a excisão ampla convencional. Objetivo: Descrever as características clinico-patológicas do CQ periocular tratado com CMM em um centro universitário terciário no Chile. Métodos: Estudo retrospectivo unicêntrico de pacientes com CQ localizado na região periocular, submetidos à CMM entre 2017 e 2022. Detalhes da CMM foram registrados. Resultados: Foram incluídos 113 pacientes com carcinomas perioculares. A média de idade foi de 59 ± 13 anos; 52% eram mulheres. A localização mais frequente foi o canto medial do olho (53%), seguido da pálpebra inferior (30,1%). O tipo histológico mais frequente de carcinoma basocelular (CBC) foi o nodular (59,3%). Em relação à CMM, o número médio de estágios foi de 1,5 ± 0,7, e 54% dos casos necessitaram de apenas um estágio para atingir margens livres. Até o momento, nenhuma recorrência foi relatada. Tumores maiores que 8,5 mm em seu maior diâmetro ou 43,5 mm² foram mais propensos a necessitar de reconstrução complexa.