Influencia de la intensidad de la caída del racimo sobre los compuestos bioactivos y la composición de ácidos grasos en la avellana

This study was conducted to determine how the intensity of the cluster drop effects nut traits, bioactive compounds, and fatty acid composition in Tombul, Palaz and Kalınkara hazelnut cultivars. The cluster drop significantly affected bioactive compounds and fatty acid composition while it did not affect the traits of the nuts. As cluster drop intensity increased, nut traits and bioactive compounds in all cultivars increased. Strong cluster drop intensity determined the highest total phenolics, total flavonoids, and antioxidant activity. Except for the Kalınkara cultivar, a low amount of linoleic acid was detected while high amounts of oleic and stearic acid were determined in slight cluster drop intensity. As cluster drop intensity increased, palmitic acid increased. Principal component analysis showed that the slight and intermediate drop intensity were generally associated with kernel length, oleic, linoleic, stearic, palmitoleic, 11-eicosenoic and arachidic acids. In contrast, strong intensity was associated with nut and kernel weight, kernel ratio, kernel width, kernel thickness, kernel size, bioactive compounds, and palmitic acid. As a result, the bioactive compounds and fatty acid composition, which are important for human health, was significantly affected by cluster drop intensity.El estudio se realizó para determinar el efecto de la intensidad de la caída de los racimos en las características de las avellanas, los compuestos bioactivos y la composición de ácidos grasos en cultivares de avellanas Tombul, Palaz y Kalınkara. La caída del racimo afectó significativamente a la composición de bioactivos y ácidos grasos, mientras que no afectó a las características de la avellana. A medida que aumentaba la intensidad de la caída de los racimos, aumentaban los compuestos bioactivos en todos los cultivares. La fuerte intensidad de caída de los racimos determinó que los fenoles totales, los flavonoides totales y la actividad antioxidante fueran más altos. Excepto para el cultivar Kalınkara, con un bajo contenido de ácido linoleico, un alto contenido de los ácidos oleico y esteárico se determinó en una ligera intensidad de caída de racimos. A medida que aumentaba la intensidad de la caída de los racimos, aumentaba el ácido palmítico. El análisis de componentes principales mostró que la intensidad de caída leve e intermedia generalmente se agrupaba con la longitud del grano, los ácidos oleico, linoleico, esteárico, palmitoleico, 11-eicosenoico y araquídico. En contraste, la intensidad fuerte se agrupó con el peso de la avellana y el grano, la proporción del grano, el ancho del grano, el grosor del grano, el tamaño del grano, los compuestos bioactivos y el ácido palmítico. Como resultado, la composición de compuestos bioactivos y ácidos grasos, que es eficaz para la salud humana, se vio significativamente afectada por la intensidad de la caída del grupo

A connection management protocol for promoting cooperation in Peer-to-Peer networks

Cataloged from PDF version of article.The existence of a high degree of free riding in Peer-to-Peer (P2P) networks is an important threat that should be addressed while designing P2P protocols. In this paper we propose a connection-based solution that will help to reduce the free riding effects on a P2P network and discourage free riding. Our solution includes a novel P2P connection type and an adaptive connection management protocol that dynamically establishes and adapts a P2P network topology considering the contributions of peers. The aim of the protocol is to bring contributing peers closer to each other on the adapted topology and to push the free riders away from the contributors. In this way contribution is promoted and free riding is discouraged. Unlike some other proposals against free riding, our solution does not require any permanent identification of peers or a security infrastructure for maintaining a global reputation system. It is shown through simulation experiments that there is a significant improvement in performance for contributing peers in a network that applies our protocol. © 2007 Elsevier B.V. All rights reserved

Molten-Salt-Assisted Self-Assembly (MASA)-Synthesis Mesoporous Metal Titanate-Titania, Metal Sulfide-Titania, and Metal Selenide-Titania Thin Films

Cataloged from PDF version of article.New synthetic strategies are needed for the assembly of porous metal titanates and metal chalcogenite-titania thin films for various energy applications. Here, a new synthetic approach is introduced in which two solvents and two surfactants are used. Both surfactants are necessary to accommodate the desired amount of salt species in the hydrophilic domains of the mesophase. The process is called a molten-salt-assisted self-assembly (MASA) because the salt species are in the molten phase and act as a solvent to assemble the ingredients into a mesostructure and they react with titania to form mesoporous metal titanates during the annealing step. The mesoporous metal titanate (meso-Zn2TiO4 and meso-CdTiO3) thin films are reacted under H2S or H2Se gas at room temperature to yield high quality transparent mesoporous metal chalcogenides. The H2Se reaction produces rutile and brookite titania phases together with nanocrystalline metal selenides and H2S reaction of meso-CdTiO3 yields nanocrystalline anatase and CdS in the spatially confined pore walls. Two different metal salts (zinc nitrate hexahydrate and cadmium nitrate tetrahydrate) are tested to demonstrate the generality of the new assembly process. The meso-TiO2-CdSe film shows photoactivity under sunlight

Fabrication of Mesoporous Metal Chalcogenide Nanoflake-Silica Thin Films and Spongy Mesoporous CdS and CdSe

Cataloged from PDF version of article.Mesoporous silica metal oxide (ZnO and CdO) thin films have been used as metal ion precursors to produce the first examples of mesoporous silica metal sulfide (meso-SiO2@ZnS, meso-SiO2@CdS) or silica metal selenide (meso-SiO2@ZnSe, meso-SiO2@CdSe) thin films, in which the pore walls are made up of silica and metal sulfide or metal selenide nanoflakes, respectively. A gentle chemical etching with a dilute HF solution of the meso-SiO2@CdS (or meso-SiO2@CdSe) produces mesoporous cadmium sulfide (meso-CdS) (or cadmium selenide, meso-CdSe). Surface modified meso-CdS displays bright blue photoluminescence upon excitation with a UV light. The mesoporous silica metal oxides are formed as metal oxide nanoislands over the silica walls through a self-assembly process of a mixture of metal nitrate salt-two surfactants-silica source followed by calcination step. The reactions, between the H2S (or H2Se) gas and solid precursors, have been carried out at room temperature and monitored using spectroscopy and microscopy techniques. It has been found that these reactions are: 1) taking place through the diffusion of sulfur or selenium species from the top metal oxide layer to the silica metal oxide interface and 2) slow and can be stopped at any stage to obtain mesoporous silica metal oxide metal sulfide or silica metal oxide metal selenide intermediate thin films

Assembly of Molten Transition Metal Salt-Surfactant in a Confined Space for the Synthesis of Mesoporous Metal Oxide-Rich Metal Oxide-Silica Thin Films

Cataloged from PDF version of article.ABSTRACT: Uniform and homogeneous coating of mesoporous materials with an active (catalytically, photonic, electrical) nanostructure can be very useful for a number of applications. Understanding chemical reactions in a confined space is important in order to design new advanced materials. In this work, we demonstrate that an extensive amount (as high as 53 mol percent) of transition metal salts can be confined between silica walls and two surfactant domains (cetyltrimethylammonium bromide, CTAB, and lauryl ether, C12H25(OCH2CH2)10OH, C12EO10) as molten salts and then converted into sponge-like mesoporous silica metal oxides by thermal annealing. This investigation has been carried out using two different salts, namely, zinc nitrate hexahydrate, [Zn(H2O)6](NO3)2, and cadmium nitrate tetrahydrate, [Cd(H2O)4](NO3)2, in a broad range of salt concentrations. The ZnO (or CdO) layers are as thin as about ∼1.6 nm and are homogenously coated as crystalline nano-islands over the silica pore walls

Effect of Helicobacter pylori infection on deep vein thrombosis seen in patients with Behçet's disease

Objective: To investigate the role of homocysteine metabolism due to Helicobacter pylori infection on the development of deep vein thrombosis (DVT) in patients with Behcet's disease (BD). Design: Prospective clinical study. Setting: Teaching hospital. Subject: Fifty-five patients with BD divided into groups, with DVT and without DVT, 19 healthy individuals and 18 patients with coronary artery disease (CAD) were enrolled into the study. Interventions: Plasma homocysteine and Hp seropositivity were determined. Results: There was significant Hp positivity in all groups (p>0.05). Homocysteine levels were not significantly different for each group except patients with CAD (p>0.05). Conclusion: There was no difference for frequency of Hp infection in all groups. We conclude that Hp does not influence DVT seen in BD via homocysteine metabolism, but the methinnin-loading test would be appropriate for enlighting patients whose fasting plasma homocysteine levels are found to be normal. East African Medical Journal Vol. 83(1) 2006: 49-5

Modifying titania using the molten-salt-assisted self-assembly process for cadmium selenide-quantum dot-sensitized photoanodes

Sensitizing titania with semiconducting quantum dots (QDs) is an important field for the development of third-generation photovoltaics. Many methods have been developed to effectively incorporate QDs over the surface of mesoporous titania, assembled from the 20-25 nm titania nanoparticles. Here, we introduce a molten-salt-assisted self-assembly (MASA) method to fabricate CdSe-modified mesoporous titania photoanodes. A mixture of ethanol, two surfactants (cetyltrimethylammonium bromide and 10-lauryl ether), silica (tetramethyl orthosilicate) or titania source (Ti(OC4H9)4, acid (HNO3), and cadmium nitrate solution was infiltrated into the pores of mesoporous titania (assembled using Degussa 25, P25) and immediately calcined at 450 °C to obtain mesoporous cadmium oxide-silica-titania (meso-CdO-SiO2-P25) or cadmium titanate-titania (meso-CdTiO3-P25) films. The MASA process is a simple method to smoothly coat or fill the pores of titania with mesoporous CdO-SiO2 or CdTiO3 that can be reacted under an H2Se atmosphere to convert cadmium species to CdSe at 100 °C. Etching of the silica films with a very dilute hydrogen fluoride solution produces mesoporous CdSe-titania (meso-CdSe-P25) electrodes. The method is flexible to adjust the CdSe/TiO2 mole ratio over a very broad range in the films. The films were characterized at every stage of the preparation to demonstrate the effectiveness of the method. The electrodes were also tested in a simple two-electrode solar cell to demonstrate the performance of the electrodes that have a power conversion efficiency of 3.35%. © 2017 American Chemical Society

Impact of COVID-19 on Formal Education: An International Review of Practices and Potentials of Open Education at a Distance.

In terms of scale, shock, and disenfranchisement, the disruption to formal education arising from COVID-19 has been unprecedented. Anecdotally, responses from teachers and educators around the world range from heightened caution to being inspired by distance education as the 'new normal.' Of all the challenges, face-to-face and formal teaching have been most heavily affected. Despite some education systems demonstrating resilience, a major challenge is sustaining quality and inclusiveness in formal education suddenly delivered at a distance. In probing these issues, this article profiles international perspectives on the role of open education in responding to the impact on formal school and higher education caused by the COVID-19 pandemic. We proceed by highlighting and analysing practices and case studies from 13 countries representing all global regions, identifying and discussing the challenges and opportunities that have presented themselves. Reports cover the period from the beginning of 2020 until 11 March 2021, the first anniversary of the COVID-19 outbreak as declared by the World Health Organization. In our comparative study, we identify seven key aspects of which three (missing infrastructure and sharing OER, open education and access to OER, and urgent need for professional development and training for teachers) are directly related to open education at a distance. After comparing examples of existing practice, we make recommendations and offer insights into how open education strategies can lead to interventions that are effective and innovative¿to improve formal education at a distance in schools and universities in the future