243 research outputs found

    Inhibición de la oxidación de la manteca de cerdo por fracciones de diferentes aceites esenciales

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    The ability to inhibit lard oxidation by the essential oils of Origanum vulgare L. spp. hirtum , Thymus vulgaris L., Thymus serpyllum L., Satureja montana L. and Satureja cuneifolia Ten. was examined. Except Satureja cuneifoila Ten. essential oil, all the essential oils studied showed a strong phenolic profile characterized by the presence of phenolic monoterpenes - thymol and carvacrol. The Rancimat method has been applied on lard spiked with essential oils and their fractions. The ability of the essential oils tested and their fractions to act as inhibitors of the lipid oxidation process was lower in comparison with reference antioxidants (BHA and BHT), ascorbic acid and a -tocopherol). The antioxidant effect of the antioxidants tested was dose-dependent. Induction time of pure lard is not effected by the quantity of the oil sample in the reacting system.Se examinó la capacidad de los aceites esenciales de Origanum vulgare L. spp. hirtum , Thymus vulgaris L., Thymus serpyllum L., Satureja montana L. y Satureja cuneifolia Ten. para inhibir la oxidación de la manteca de cerdo pura. Excepto Satureja cuneifolia Ten., todos los aceites esenciales mostraron un acusado perfil fenólico caracterizado por la presencia de fenoles monoterpénicos- timol y carvacrol. El método Rancimat ha sido aplicado a manteca de cerdo sembrada con los aceites esenciales y sus fracciones. La capacidad de los aceites y sus fracciones para actuar como inhibidores de la oxidación de lípidos fue menor en comparación con la de antioxidante sintéticos (BHA y BHT), ácido ascórbico y a -tocoferol. El efecto antioxidante de las sustancias ensayadas dependió de la dosis. El periodo de inducción de la manteca de cerdo pura no se afectó por la cantidad de muestra presente en el sistema de reacción

    ENERGY AUDIT – METHOD FOR ENERGY CONSERVATION IN HOTELS

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    In the very near future, energy efficient hotels will cease to be the exception but will be the rule. Energy conservation and the intelligent utilization of renewable energy sources are prerequisite for sustainable development of tourism. Due to global warming and increased standards in hotel industry, there is an increasing demand for energy for cooling in general, although this is especially reflected in hotel industry peaking in summer period. Furthermore, energy demand for hot water and food and beverages preparation in a hotel increases proportionally with the number of tourists. All these energy issues are overburdening the ever competing hotel industry. Hotels, in order to optimize their energy costs and implementation of renewable energy sources utilization, have to perform energy audit - an analysis of thermal performance and energy systems of building with the purpose to determent its energy efficiency or non-efficiency. This paper combines energy audit methodology with properties of energy consumption in hotel industry with an aim to provide guidelines for modern hotel energy management

    TOURISM AS A PATHWAY FOR RES UTILISATION

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    Tourism, due its property of being an “invisible export” sector, has a strong multiplier effect over the economy. Tourists boost demand for numerous goods and services, one of them being energy. Unfortunately, energy sources are scarce for most of the countries in the region. Thus, one could think of another solution to the excess demand for energy than import. Namely, for more than a decade, renewable energy sources are in the central focus of the EU energy policy with an aim to ensure security, price stability, availably and affordability of energy to its citizens together with reduction of GHG emissions and making the EU economy more competitive. Combining tourism with renewable energy sources utilisation helps reducing the spill over effect from energy import. In this paper, the cross-section analysis based on environmental determination of tourism and renewable energy sources potentials is performed in order to indicate a pathway for implementation of renewable energy sources utilisation in the tourism and hotel industry

    Functionalization of Pyrene To Prepare Luminescent Materials—Typical Examples of Synthetic Methodology

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    Pyrene-based π-conjugated materials are considered to be an ideal organic electro-luminescence material for application in semiconductor devices, such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs) and organic photovoltaics (OPVs), and so forth. However, the great drawback of employing pyrene as an organic luminescence material is the formation of excimer emission, which quenches the efficiency at high concentration or in the solid-state. Thus, in order to obtain highly efficient optical devices, scientists have devoted much effort to tuning the structure of pyrene derivatives in order to realize exploitable properties by employing two strategies, 1) introducing a variety of moieties at the pyrene core, and 2) exploring effective and convenient synthetic strategies to functionalize the pyrene core. Over the past decades, our group has mainly focused on synthetic methodologies for functionalization of the pyrene core; we have found that formylation/acetylation or bromination of pyrene can selectly lead to functionalization at K-region by Lewis acid catalysis. Herein, this Minireview highlights the direct synthetic approaches (such as formylation, bromination, oxidation, and de-tert-butylation reactions, etc.) to functionalize the pyrene in order to advance research on luminescent materials for organic electronic applications. Further, this article demonstrates that the future direction of pyrene chemistry is asymmetric functionalization of pyrene for organic semiconductor applications and highlights some of the classical asymmetric pyrenes, as well as the latest breakthroughs. In addition, the photophysical properties of pyrene-based molecules are briefly reviewed. To give a current overview of the development of pyrene chemistry, the review selectively covers some of the latest reports and concepts from the period covering late 2011 to the present day

    Antioxidant activity of twenty wild Spanish Thymus mastichina L. populations and its relation with their chemical composition

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    The antioxidant activity and chemical composition of essential oils and methanolic extracts of twenty Spanish Thymus mastichina L. populations were studied. Both essential oils and methanolic extracts possessed antioxidant properties. However, the total phenol contents of the methanolic extracts varied between 2.90 and 9.15mg GAE/g extract and the EC 25 values of DPPH free radical scavenging activity between 0.90 and 3.45mg/mL for the methanolic extracts and 78-241mg/mL for essential oils, these showing low antioxidant potential. Actually, in essential oils the main compound determined was the 1,8-cineole (56.8-69.6%), whereas thymol, γ-terpinene, terpinolene and geraniol (species with considerable DPPH scavenging activity) were observed in low amounts. Concerning methanolic extracts, rosmarinic acid was the most abundant polyphenol (1.70-9.85mg/g), followed by methoxysalicylic acid, apigenin, kaempferol and luteolin.The authors are grateful to the POCTEPePrograma Cooperação Transfronteiriça España-Portugal 2007 e 2013 for financial support through the project “Mejora de la competitividad del sector agrario de Castilla y León y Norte de Portugal a través de la innovación y el desarrollo de productos diferenciados de alto valor”.info:eu-repo/semantics/publishedVersio

    Review: Pharmacological effects of Capparis spinosa L.

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    Medicinal plants have been known as one of the most important therapeutic agents since ancient times. During the last two decades, much attention has been paid to the health-promoting effects of edible medicinal plants, because of multiple beneficial effects and negligible adverse effects. Capparis spinosa L. is one of the most common medicinal plants, used widely in different parts of the world to treat numerous human diseases. This paper aims to critically review the available scientific literature regarding the health-promoting effects of C. spinosa, its traditional uses, cultivation protocols and phytochemical constituents. Recently, a wide range of evidence has shown that this plant possesses different biological effects, including antioxidant, anticancer and antibacterial effects. Phytochemical analysis shows that C. spinosa has high quantities of bioactive constituents, including polyphenolic compounds, which are responsible for its health-promoting effects, although many of these substances are present in low concentrations and significant changes in their content occur during processing. In addition, there is negligible scientific evidence regarding any adverse effects. Different health promotion activities, as well as tremendous diversity of active constituents, make C. spinosa a good candidate for discovering new drugs. However these findings are still in its infancy and future experimental and clinical studies are needed

    Mathematical modeling of gallic acid release from chitosan films with grape seed extract and carvacrol

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    Controlled release of antimicrobial and antioxidant compounds from packaging films is of utmost importance for extending the shelf-life of perishable foods. This study focused on the mathematical modeling of gallic acid release into an aqueous medium from three chitosan films, formulated with grape seed extract (GSE) and carvacrol. We quantified the release by HPLC technique during 30days at three temperatures (5, 25 and 45°C). The diffusion coefficients, varying with temperature according to an Arrhenius-type relationship, and the respective activation energies for Film-1 and Film-2 were, respectively [Formula: see text] m2s-1 and [Formula: see text] m2s-1, Ea1=58kJmol-1 and Ea2=60kJmol-1 as obtained from the Fickian fit. The low concentrations of gallic acid released by Film-3 could not be detected by HPLC, therefore the respective diffusion coefficient was not estimated. This study will help with the development and optimization of active packaging (AP) films aiming at improved food preservation and shelf-life extension.Javiera F. Rubilar gratefully acknowledges her Ph.D. grant from ErasmusMundus 2008-1022/001 Frame ECW/17, EACEA(European Union), financial support of the Fondecyt-Postdoctoral #3140349 project from CONICYT, and also “Dirección de Investigación e Innovación Escuela de Ingeniería” at Pontificia Universidad Católica de Chile. Rui M. S. Cruz acknowledges grant SFRH/BPD/70036/2010 from Fundac¸ ão para a Ciência e Tecnologia, Portugalinfo:eu-repo/semantics/publishedVersio

    Coupling shRNA screens with single-cell RNA-seq identifies a dual role for mTOR in reprogramming-induced senescence

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    Expression of the transcription factors OCT4, SOX2, KLF4, and cMYC (OSKM) reprograms somatic cells into induced pluripotent stem cells (iPSCs). Reprogramming is a slow and inefficient process, suggesting the presence of safeguarding mechanisms that counteract cell fate conversion. One such mechanism is senescence. To identify modulators of reprogramming-induced senescence, we performed a genome-wide shRNA screen in primary human fibroblasts expressing OSKM. In the screen, we identified novel mediators of OSKM-induced senescence and validated previously implicated genes such as CDKN1A. We developed an innovative approach that integrates single-cell RNA sequencing (scRNA-seq) with the shRNA screen to investigate the mechanism of action of the identified candidates. Our data unveiled regulation of senescence as a novel way by which mechanistic target of rapamycin (mTOR) influences reprogramming. On one hand, mTOR inhibition blunts the induction of cyclin-dependent kinase (CDK) inhibitors (CDKIs), including p16INK4a, p21CIP1, and p15INK4b, preventing OSKM-induced senescence. On the other hand, inhibition of mTOR blunts the senescence-associated secretory phenotype (SASP), which itself favors reprogramming. These contrasting actions contribute to explain the complex effect that mTOR has on reprogramming. Overall, our study highlights the advantage of combining functional screens with scRNA-seq to accelerate the discovery of pathways controlling complex phenotypes

    Enhancement of the Performance of Perovskite Solar Cells, LEDs, and Optical Amplifiers by Anti-Solvent Additive Deposition

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    The efficiency of perovskite optoelectronic devices is increased by a novel method; its suitability for perovskite solar cells, light-emitting diodes, and optical amplifiers is demonstrated. The method is based on the introduction of organic additives during the anti-solvent step in the perovskite thin-film deposition process. Additives passivate grain boundaries reducing non-radiative recombination. The method can be easily extended to other additives
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