157 research outputs found

    A survey of the in vitro antifungal activity of heather (Erica sp.) organic honey

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    Monofloral heather (Erica sp.) honey samples (n = 89), harvested in Portugal according to European organic beekeeping rules, were analyzed to test their antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The specific growth rate (l) values showed that growth of all the yeasts was reduced in the presence of honey. The honey concentration (% wt/vol) that inhibited 10% of the yeast growth (Xmin) was 13.5% for C. albicans, 20.5% for C. krusei, and 17.1% for C. neoformans. The respective concentrations of heather honey and synthetic honey in the C. krusei culture medium above 60% (wt/vol) that inhibited 90% of the yeast growth (Xmax) and Xmin, respectively, were established, whereas C. albicans and C. neoformans were more resistant because Xmax values were not reached over the range tested (10–60%, wt/vol). Heather honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. Further studies are now required to demonstrate if this antifungal activity has any clinical application

    Study of organic honey from the Northeast of Portugal

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    Concerns about traces of numerous toxic substances and authenticity have prompted consumer demand for honey that is certified as organic, based on strict ecological, natural principles and traceability. The present study aims to characterize organic honey samples (n = 73) from Northeast Portugal, with respect to floral nectar origin, physicochemical parameters and microbial safety. The phenols and flavonoids contents, often referred to as responsible for honey’s bioactive properties, were also assessed. All organic honey samples were classified as monofloral lavender (Lavandula sp.), exceeded in quality the international physicochemical standards and showed low microbiological counts (yeast, moulds and aerobic mesophiles), with negative results in respect to fecal coliforms, Salmonella and sulphite-reducing Clostridium spp. Correlation of the palynological, physicochemical and microbiological results is necessary to check the authenticity, quality and sanitation of honey. Although not required by international legislation, results of those assessments provide a complete outlook and elucidation of the organic honey’s properties, which could promote its valorisation

    Antifungal effect of lavender honey against Candida albicans, Candida krusei and Cryptococcus neoformans

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    Monofloral lavender honey samples (n=30), were analyzed to test antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. The specific growth rates (μ) showed that all the yeast growths were reduced in the presence of honey. The honey concentration (% w/v) that inhibited 10% of the yeasts growth (Xmin) ranged from 31.0% (C. albicans), 16.8% (C. krusei) and 23.0% (C. neoformans). A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The presence of synthetic honey in the C. krusei culture medium at concentrations above 58.0% (w/v) was established as Xmin, while C. albicans and C. neoformans were more resistant, since Xmin values were not reached over the ranged tested (10–60%, w/v). What the data suggests is that the component in the lavender honey responsible for the observed antifungal in vitro properties is not sugar based. Honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. This could be very useful, onsidering the increasing resistance of antifungals. It should be noticed that this is the first study concerning the effect of lavender honey on the growth of pathogenic yeasts

    Métodos de aproximación de solucións na Teoría de Xogos

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    Traballo Fin de Grao en Matemáticas. Curso 2021-2022A teoría de xogos cooperativa céntrase principalmente en analizar os seguintes dous aspectos dunha interacción multi-axente: qué coalicións se formarán e cómo será repartido o beneficio (ou custe) xerado entre os diferentes individuos involucrados. Para realizar esta distribución seguindo criterios como a xustiza ou a equidade, establécense as chamadas regras de reparto, que serán consideradas solucións dos xogos cooperativos. Sen embargo, cando o número de axentes involucrados é relativamente grande, o cómputo exacto destas solucións adoita presentar unha elevada complexidade computacional, sendo necesaria así a súa aproximación. Ao longo deste traballo, repasaremos os procesos de estimación presentados na literatura tanto para o valor de Shapley e o valor de Banzhaf, como para as súas extensións a situacións con estruturas de prioridade, o valor de Owen e o valor de Banzhaf-Owen. Ademáis, mediante a implementación en R destes algoritmos, calcularemos novas cotas de leite en Galicia ao supoñer unha redución da produción con respecto a 2015.Cooperative game theory focuses mainly on analyzing the following two aspects of a multiagent interaction: what coalitions will be formed and how the benefit (or cost) generated will be shared among the different individuals involved. For allocating according to different criteria such as justice or fairness, the so-called allocation rules are established, which will be considered solutions of the cooperative games. However, when the number of agents involved is relatively large, the exact computation of these solutions presents a high computational complexity, thus making its approximation necessary. Along this work, we will review the estimation processes presented in the literature for the Shapley value and the Banzhaf value, as well as for their extensions to situations with a priori unions, the Owen value, and the Banzhaf-Owen value. In addition, by implementing these algorithms in R, we will calculate new milk quotas in Galicia by assuming a reduction in the production with respect to 2015

    Antimicrobial activity, phenolic profile and role in the inflammation of propolis

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    Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile, the in vitro antimicrobial activity and effect in the hyaluronidase enzyme (widely related with the inflammation process) of propolis harvested in Portugal. The efficacy of three extracts (hydro-alcoholic, methanolic and aqueous) was also compared. It was chosen the hydroalcoholic extract, because this was the most effective for extracting phenolic compounds. The antimicrobial activity was accessed in Gram-positive and Gram-negative bacteria and yeasts, isolated from different biological fluids and the results were then compared with the obtained for reference microorganisms. The propolis from Bragança was the one that possessed the highest polyphenols’ content. The sample from Beja showed the less significant inhibition of the hyaluronidase enzyme. Concerning the antimicrobial activity, Candida albicans was the most resistant and Staphylococcus aureus the most sensitive. The reference microorganisms were more sensitive than the ones isolated from biological fluids

    Waste management in civil engineering: a dynamic framework

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    [Abstract:] The recycling and later use of construction and demolition waste (C&D waste) as construction materials present a strategic inconvenience for many stakeholders involved in the sustainable construction. In some countries, the recycling percentage of C&D waste is around 80% of the C&D generated. However, in other countries this percentage is much lower. This complexity requires a better understanding of the recycling dynamic. In the specific case of Spain, the National Integrated Waste Management Plan (PNIR 2008-2015) suggests a number of goals for recycling and recovery of building materials that are difficult to meet without laying down policies intended to stimulate the companies´ behaviour of consumption of recycled C&D waste. This paper presents a conceptual framework within which the issue of recycling can be raised from a multidisciplinary approach, taking into account the technical conditioning factors as well as the socioeconomic aspects that might influence the behaviour of companies and the government. On the basis of a systemic problem approach, a dynamic simulation model was designed to evaluate the consequences of incentives policies by promoting the use of recycled aggregates. Actions aimed at increasing the use of C&D waste materials in construction, by providing economic incentives to the industry, are proposed as a short-term policy to balance the achievement of goals for sustainable construction in the future. This conceptual framework possesses a transferable potential that might be applied to other countries involved in the same dynamic.Ministerio de Educación y Ciencia; BIA 2010-17751Consellería de Innovación; 10MDS012C

    Characterization of artisanal honey produced on the Northwest of Portugal by melissopalynological and physico-chemical data

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    Honey has always been regarded as a food which is advantageous for one’s health and as a product which has healing qualities. For this reason, is necessary to protect consumers from the fraudulent mislabeling of inferior honeys. The purpose of this study was to investigate some properties of artisanal honey samples (n = 45) collected from the Northwest of Portugal by using different honey analysis tests such as moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural (HMF), apparent sucrose, reducing sugars and diastase activity. 77.8% of the total exceeded the quality parameters and should be labeled as ‘‘virgin” (humidity 618% and HMF 6 25 mg/kg). The present study found a linear correlation (y = 0.551x 0.089; R = 0.995) between the electrical conductivity of honeys and their ash content. All of the samples showed an Erica sp. pollen percentageP15%, and 42% of the total were monofloral Erica sp. In respect to coliforms and Salmonella’s presence, all the honey’s samples shown to be negative. The existence of sulphite-reducing Clostridia was low, and well below the established limit by MERCOSUR. Yeasts, moulds and aerobic mesophiles were detected in low amounts

    Estudio de la determinación de ftalatos en muestras de interés clínico y alimentario

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    Los diésteres del ácido ftálico, comunmente conocidos como ftalatos, son compuestos químicos usados en la industria desde 1930. A nivel industrial, el interés de estos compuestos radica en sus propiedades físico-químicas, que los convierten en los aditivos idóneos en la fabricación de polímeros por la función plastificante que desempeñan. Desde el punto de vista de la Salud Pública, el interés de los ftalatos se debe a los riesgos para la salud que se derivan de la presencia de estas sustancias en nuestro entorno (suelo, agua, aire, alimentos…) y que tiene como consecuencia su aparición en el organismo humano. Algunos de los ftalatos que han sido objeto de estudio en este trabajo como el BBP, DBP y DEHP han sido clasificados como tóxicos para la reproducción (categoría 2) por la Unión Europea. En esta Tesis se pone de manifiesto la presencia de distintos ftalatos en varios tipos de muestras. En todos los casos, los ftalatos analizados provienen de la liberación de los mismos desde diferentes plásticos (envases monodosis, bolsas de infusión, lentes de contacto y films transparentes) donde desarrollan su función como plastificantes. La técnica de análisis utilizada ha sido la cromatografía líquida de alta resolución acoplada a la espectrometría de masas, simple y en tándem. Se seleccionó esta técnica por su gran sensibilidad y se evitó, en la medida de lo posible, la manipulación de las muestras con el fin de minimizar los problemas de contaminación inherentes al análisis de estos compuestos

    Comprehensive study of honey with protected denomination of origin and contribution to the enhancement of legal specifications

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    In this study the characterization of a total of 60 honey samples with Protected Denomination of Origin (PDO) collected over three harvests (2009–2011, inclusive), from the Northeast of Portugal was carried out based on the presence of pollen, physicochemical and microbiological characteristics. All samples were found to meet the European Legislation, but some didn’t meet the requirements of the PDO specifications. Concerning the floral origin of honey, our results showed the prevalence of rosemary (Lavandula pedunculata) pollen. The microbiological quality of all the analyzed samples was satisfactory, since fecal coliforms, sulfite-reducing clostridia and Salmonella were absent, and molds and yeasts were detected in low counts. Significant differences between the results were studied using one-way analysis of variance (ANOVA), followed by Tukey’s HSD test. The samples were submitted to discriminant function analysis, in order to determine which variables differentiate between two or more naturally occurring groups (Forward Stepwise Analysis). The variables selected were in this order: diastase activity, pH, reducing sugars, free acidity and HMF. The pollen spectrum has perfect discriminatory power. This is the first study in which a honey with PDO was tested, in order to assess its compliance with the PDO book of specifications
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