2,906 research outputs found

    Modeling the kinetics of peroxidase inactivation, colour and texture changes of Portuguese cabbage (Brassica oleracea L. var. costata DC) during UV-C light and heat blanching

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    The e ects of heat blanching and UV-C light followed by heat on Portuguese cabbage peroxidase (POD), colour and texture were studied in the temperature range of 80-95 °C. POD inactivation, lightness (L) and yellowness (b) colour changes were described by a rst-order reaction model. The greenness (a) colour and texture ( rmness) changes followed a two fraction kinetic model behaviour. The temperature e ect was well described by the Arrhenius law. At lower temperatures the combined treatment showed higher POD inactivation. Colour and texture parameters did not show signi cant di erences between treatments. Long processing times turned the leaves slightly darker, decreased greenness, yellowness and rmness. Short processing times increased the rmness and greenness of the leaves. The treatment at 80 °C for 90 seconds reduced 90% of POD, retaining 98% of lightness and 92% of yellowness and improved the green colour (130%) and rmness (125%). At 80 °C the heat blanching required 7.4 min to inactivate 90% of the enzyme activity, reducing lightness, greenness, yellowness and rmness to 92%, 68%, 62% and 61%, respectively. The present ndings will help to optimize the Portuguese cabbage blanching conditions.info:eu-repo/semantics/publishedVersio

    Antioxidant Activity and Cytotoxicity of Taraxacum hispanicum Aqueous and Ethanolic Extracts on HepG2 Cells

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    Plants belonging to the genus Taraxacum have been used in traditional medicine. Nowadays, extracts of these plants have been reported for the treatment of diseases, including liver disorders. Increasing interest and research on these plants also revealed its potential for treating cancer. This study aims to evaluate the antioxidant activity and cytotoxic properties of crude extracts from aerial parts of Taraxacum hispanicum H.Lindb, against human hepatocarcinoma (HepG2). Material and methods: Evaluation of the antioxidant properties was performed using DPPH in vitro test, superoxide scavenging assay and Fe2+ chelating activity. MTT assay was used to determine metabolic activity, for 24 and 48 hours.info:eu-repo/semantics/publishedVersio

    Estudos soroepidemiológico e molecular de infecção por EV-71 no Estado do Pará, Brasil

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    In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Pará showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.Em muitos países, o Enterovírus 71 (EV-71) família Picornaviridae é associado a doença de pé-mão e boca e doenças neurológicas agudas enquanto que no Brasil esse vírus está mais associado às últimas. O objetivo desta pesquisa foi utilizar em estudos moleculares e soroepidemiológicos, o primeiro isolamento de EV-71 obtido na região norte do Brasil. No período de janeiro de 1998 a dezembro de 2000 foram coletadas 88 amostras (44 casos de PFA) de fezes das quais, duas (2,2%) foram positivas para EV-71 (73442/PA/99). A seqüência de nucleotídeos do gen que codifica a proteína VP1 mostrou que o isolado 73442/PA/99 foi similar às cepas de EV-71 pertencentes ao grupo B- mais próxima das norte americanas. Teste de neutralização com 389 amostras de soro colhidas no período de janeiro de 1998 a novembro de 2001, de indivíduos com idade de 0 a 15 anos residentes na cidade de Belém, Estado do Pará mostrou os seguintes resultados em relação ao isolado 73442/PA/99 e ao protótipo BrCr: 207 indivíduos (53,2%) tinham anticorpos neutralizantes para ambos os vírus, 167 (42,9%) não tinham anticorpos e 15 tinham anticorpos para um dos dois vírus. Somente 20,2% das crianças com idade de 0 a 3 anos tinham anticorpos neutralizantes para EV-71, indicando que essas crianças estavam mais suscetíveis à infecção. Tanto o estudo de soroprevalência quanto o de sequenciamento da VP1 foram importantes para demonstrar a propagação e o padrão molecular do EV-71 circulante na região norte do Brasil

    Detection of apoptotic events, using different methods, in renal tissues after acute haemorrhage.

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    Apoptosis plays an important role in cellular damage caused by acute renal hypoperfusion. The aim of this study was to detect apoptotic events in an animal model of acute haemorrhage, followed by volume replacement with different intravenous solution

    Período crítico de competencia de la Zanahoria (Daucus carota L.) y malezas asociadas al cultivo

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    Las malezas constituyen uno de los problemas fitosanitarios que afectan la rentabilidad de los cultivos. El periodo crítico de competencia con el cultivo (PCC), permite prever el nivel de interferencia de las malezas sobre la producción del cultivo de interés. El objetivo de esta investigación fue determinar el PCC entre zanahoria y las plantas asociadas al cultivo, en el municipio de Ventaquemada, departamento de Boyacá, implementando un diseño en Bloques Completos al Azar, con 12 tratamientos y cuatro repeticiones, el cual incluía un grupo de tratamientos libres de malezas por un periodo de tiempo (10, 20, 30, 40 ó 50 días), al término del cual se permitía el crecimiento de las mismas en el cultivo, de modo que el cultivo estuviese primero libre y luego en competencia (LC) y en el segundo grupo de tratamientos se permitía primero el desarrollo del proceso de competencia entre la maleza y el cultivo por un intervalo de tiempo igual al del grupo anterior y luego se retiraban las malezas. El mayor número de plantas cosechadas se obtuvo en la parcela libre de competencia durante los primeros 50 días después de emergencia. El mayor rendimiento se obtuvo en el tratamiento que se mantuvo limpio durante todo el ciclo de cultivo, con una producción de 5810g m-2, superior en 2252g a la obtenida en el punto crítico de competencia. para las condiciones evaluadas, el periodo crítico de competencia en zanahoria, se sitúa entre los 20 a 45 días, después de la emergencia del cultivo

    In vitro exposure of acer negundo pollen to atmospheric levels of SO2 and NO2: effects on allergenicity and germination

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    In the last years, a rising trend of pollen allergies in urban areas has been attributed to atmospheric pollution. In this work, we investigated the effects of SO2 and NO2 on the protein content, allergenicity, and germination rate of Acer negundo pollen. A novel environmental chamber was assembled to exposure pollen samples with SO2 or NO2 at two different levels: just below and two times the atmospheric hour-limit value acceptable for human health protection in Europe. Results showed that protein content was lower in SO2- exposed pollen samples and slightly higher in NO2-exposed pollen compared to the control sample. No different polypeptide profiles were revealed by SDSPAGE between exposed and nonexposed pollen, but the immunodetection assays indicated higher IgE recognition by all sera of sensitized patients to Acer negundo pollen extracts in all exposed samples in comparison to the nonexposed samples. A decrease in the germination rate of exposed in contrast to nonexposed pollen was verified, which was more pronounced for NO2-exposed samples. Our results indicated that in urban areas, concentrations of SO2 and NO2 below the limits established for human protection can indirectly aggravate pollen allergy on predisposed individuals and affect plant reproduction

    Portuguese propolis: a source of valuable bioactivities

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    To FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145-FEDER-006958 and FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013

    Stress ocupacional no ensino : um estudo com professores dos 3º ciclo e ensino secundário

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    Este trabalho foi realizado com 689 professores portugueses, a leccionarem nos terceiro ciclo e ensino secundário. Foram avaliados indicadores de stress, “burnout”, saúde física e satisfação profissional. Observaram-se valores significativos de stress ocupacional (perto de 40%), e de “burnout” (10% na exaustão emocional, 3% na baixa realização pessoal e 1% na despersonalização), vários problemas de saúde física e valores de insatisfação profissional perto dos 20%. As análises de regressão múltipla apontaram diferentes variáveis preditoras para as três dimensões do “burnout” (62% de variância explicada na exaustão emocional, 16% na realização pessoal e 13% na despersonalização). As análises discriminantes e “t-test” para amostras independentes demonstraram maior stress ocupacional nas mulheres, nos professores mais velhos, nos profissionais com vínculos profissionais mais precários, nos professores com mais horas de trabalho e com mais alunos em sala de aula. No final, apresentam-se as limitações do estudo e as implicações para a investigação futura.(undefined

    Parainfluenza fusion peptide promotes membrane fusion by assembling into oligomeric porelike structures

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    © 2022 The Authors. Published by American Chemical SocietyParamyxoviruses are enveloped viruses harboring a negative-sense RNA genome that must enter the host’s cells to replicate. In the case of the parainfluenza virus, the cell entry process starts with the recognition and attachment to target receptors, followed by proteolytic cleavage of the fusion glycoprotein (F) protein, exposing the fusion peptide (FP) region. The FP is responsible for binding to the target membrane, and it is believed to play a crucial role in the fusion process, but the mechanism by which the parainfluenza FP (PIFP) promotes membrane fusion is still unclear. To elucidate this matter, we performed biophysical experimentation of the PIFP in membranes, together with coarse grain (CG) and atomistic (AA) molecular dynamics (MD) simulations. The simulation results led to the pinpointing of the most important PIFP amino acid residues for membrane fusion and show that, at high concentrations, the peptide induces the formation of a water-permeable porelike structure. This structure promotes lipid head intrusion and lipid tail protrusion, which facilitates membrane fusion. Biophysical experimental results validate these findings, showing that, depending on the peptide/lipid ratio, the PIFP can promote fusion and/or membrane leakage. Our work furthers the understanding of the PIFP-induced membrane fusion process, which might help foster development in the field of viral entry inhibition.This work was financially supported by FCT-Fundação para a Ciência e a Tecnologia, Portugal, through project PTDC/CCI-BIO/28200/2017 and by the European Union (H2020-FETOPEN-2018-2019-2020-01, grant no. 828774). This work was also financially supported by Project LISBOA-01-0145-FEDER-007660 (Microbiologia Molecular, Estrutural e Celular) funded by FEDER funds through COMPETE2020_Programa Operacional Competitividade e Internacionalização (POCI). M.V. and D.A.M. thank FCT for their PhD fellowships (SFRH/BD/148542/2019 and PD/BD/136752/2018, respectively). M.N.M. thanks FCT for the Post-Doc fellowship CEECIND/04124/2017. M.N.M. and D.L. thank the MACC for the computing hours in their HPC center (CPCA/A0/7329/2020 and CPCA/A0/7305/2020).info:eu-repo/semantics/publishedVersio

    The influence of semantic and phonological factors on syntactic decisions: An event-related brain potential study

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    During language production and comprehension, information about a word's syntactic properties is sometimes needed. While the decision about the grammatical gender of a word requires access to syntactic knowledge, it has also been hypothesized that semantic (i.e., biological gender) or phonological information (i.e., sound regularities) may influence this decision. Event-related potentials (ERPs) were measured while native speakers of German processed written words that were or were not semantically and/or phonologically marked for gender. Behavioral and ERP results showed that participants were faster in making a gender decision when words were semantically and/or phonologically gender marked than when this was not the case, although the phonological effects were less clear. In conclusion, our data provide evidence that even though participants performed a grammatical gender decision, this task can be influenced by semantic and phonological factors
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