654 research outputs found
Assessing customer satisfaction and loyalty in the retail sector
info:eu-repo/semantics/publishedVersio
Highly effective SERS nanopattern substrate. The enhancement is demonstrated using thiophenol as a molecular probe
The number of different types of Surface-enhanced Raman Scattering (SERS) substrates available for experimentation is increasing at high speed. New alternatives are introduced and explored every year in the literature including both novel nano-particles in solution as well as self-assembled or engineered structures with different levels of control over their optical properties. In this work silver nanopattern obtained by the nano-sphere lithography approach was prepared and characterized by AFM. This method basically exploits the regular patterns formed by self-assembly of dielectric (polystyrene, PS) nano-spheres on a surface upon drying. The evaporation of a silver film on top of the array can be followed by the lift-off of the nano-spheres themselves in which case an array of interstitial sites is left on the surface [1-2] (Fig. 1). We have observed in the AFM images that the shape of the nanopatterns is regular but the surface is rough and they are homogeneously distributed with dimensions in the sub-wavelength range.SERS properties of this substrate were examined by using thiophenol (TP) as molecular probe through the preparation of self-assembled monolayer (SAM) by dipping the substrates for 1h in 0.1mM solution of TP in CH2Cl2 at the temperature of 25ºC. Samples were subsequently rinsed with solutions solvents and dried before scanning.
The surface interaction of this molecule has been studied by several groups and the most significant Raman change after the adsorption is the disappearance of the S-H stretching mode at about 2566 cm-1 in the SERS spectrum and indicating that an Ag-S bond has been formed [3]. The reproducibility on different areas of this substrate has been analyzed by using this molecular probe concluding that a fairly homogeneous distribution of the SERS intensity is observed (Fig. 2) which is a prerequisite for applications as ultrasensitive sensing assemblies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Novel approach for the characterisation of Sicilian honeys based on the correlation of physico-chemical parameters and artificial senses
The aim of this work was to characterise some of the most representative Sicilian honeys. Sugars, pH and minerals were determined with conventional analyses. Chestnut honeys showed the lowest sugar content, with a fructose and glucose sum of 62.31\u2009g/100g. Citrus and Eucalyptus honeys showed the highest fructose content (38.08 and 38.04\u2009g/100g), while Citrus and Sulla honeys had the highest sucrose content (3.16 and 3.92\u2009g/100g). The highest fructose to glucose ratio was 1.59, found for Chestnut honeys, which had also the highest pH-value of 4.98. Potassium is the most abundant element in honey and the highest values were found for Chestnut and Eucalyptus honey (4.412 and 1.956\u2009mg/g). Among micro-minerals, Zinc showed the highest concentration, ranging from 4.64 to 7.16 \ub5g/g. Alongside physicochemical analyses, E-tongue and computer vision was used to estimate the organoleptic proprieties of honey. In particular, Pearson\u2019s correlation was used to study the relationship between the electrical E-tongue\u2019 signals, pH and sugars content, which have a major influence on the main taste attributes investigated in honey. Chestnut honeys scored the lowest values for the sweet and sour taste, being the bitterest among the samples evaluated. On the other hand, Sulla and Citrus honeys were the sweetest and the sourest. The colour of honey was examined with machine vision and the weight of the different minerals on the colour parameters was disclosed, resulting in dark colours correlated to sodium and microelements, and in a light colour that showed a negative correlation with potassium and magnesium
Utilização de um modelo de treinamento fisico em pequenos animais para pesquisa em fisiologia
Estabilidad oxidativa de aceites de soja y maíz enriquecidos con extracto hidroalcohólico de Pluchea quitoc
Soybean and corn oils are among the most popular vegetable oils, and are ingredients which are widely used in cooking and in the food industry. These oils contain many unsaturated fatty acids such as oleic, linoleic and linolenic acids, which makes them easily oxidized by oxygen. Extensive efforts are being made to prevent or minimize vegetable oil oxidation through the development of antioxidants. Phenolic antioxidants which are present in some extracts can be used as food additives to prevent lipid oxidation. In this study chromatographic analyses (HPLC and GC) of the Pluchea quitoc hydroalcoholic extract were performed. The content of phenolic compounds by the Folin-Ciocalteau method and the antioxidant properties against radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) were also evaluated. The effect of samples prepared with soybean and corn oils enriched with Pluchea quitoc hydroalcoholic extract was determined and compared with samples of these oils which were free of antioxidants and with samples containing the synthetic antioxidant BHT. The results showed potential for application of the extract. A high content of phenolic compounds (314 milligrams of gallic acid equivalents (GAE)/g of extract) and good IC50 values were detected for the inhibition of the radicals DPPH and ABTS (13.2 µg·mL-1 and 5.6 µg·mL-1). In the evaluation of the oxidative stability of the oils enriched with this extract, it was found that at 1% concentration it was possible to obtain values of induction period (IP) close to the samples with added BHT.Los aceites de soja y maíz se encuentran entre los aceites vegetales más populares, ingredientes ampliamente utilizados en la cocina y también en la industria alimentaria. Estos aceites contienen muchos ácidos grasos insaturados como los ácidos oleico, linoleico y linolénico que se oxidan fácilmente con el oxígeno. Se están realizando grandes esfuerzos para prevenir o minimizar la oxidación de los aceites vegetales mediante el desarrollo de antioxidantes. Los antioxidantes fenólicos presentes en algunos extractos se pueden utilizar como aditivos alimentarios para prevenir la oxidación de lípidos. En este estudio se realizó la obtención y análisis cromatográficos (HPLC y GC) del extracto hidroalcohólico de Pluchea quitoc. El contenido de compuestos fenólicos se evaluó por el método de Folin-Ciocalteau y las propiedades antioxidantes frente a radicales DPPH y ABTS. Se determinó el efecto de muestras preparadas con aceites de soja y maíz enriquecidas con extracto hidroalcohólico de Pluchea quitoc y se comparó con muestras de estos aceites libres de antioxidantes y con el antioxidante sintético BHT. Los resultados mostraron potencial para la aplicación del extracto. Se detectó un alto contenido de compuestos fenólicos (314 mg GAE) y buenos valores de IC50 para la inhibición de los radicales DPPH y ABTS (13.2 µg·mL-1 y 5.6 µg·mL-1). En la evaluación de la estabilidad oxidativa de los aceites enriquecidos con este extracto, se encontró que para la concentración del 1% es posible obtener valores de período de inducción (IP) cercanos a las muestras adicionadas con BHT
Enhanced Joule Heating in Umbral Dots
We present a study of magnetic profiles of umbral dots (UDs) and its
consequences on the Joule heating mechanisms. Hamedivafa (2003) studied Joule
heating using vertical component of magnetic field. In this paper UDs magnetic
profile has been investigated including the new azimuthal component of magnetic
field which might explain the relatively larger enhancement of Joule heating
causing more brightness near circumference of UD.Comment: 8 pages, 1 figure, accepted in Solar Physic
The Quality of Five Natural, Historical Italian Cheeses Produced in Different Months: Gross Composition, Fat-Soluble Vitamins, Fatty Acids, Total Phenols, Antioxidant Capacity, and Health Index
Five natural historic cheeses of Southern Italy were investigated\u2014Caciocavallo Palermitano (CP), Casizolu del Montiferru (CdM), Vastedda della Valle del Bel\uecce (VVB), Pecorino Siciliano (PS), and Caprino Nicastrese (CN)\u2014which are produced with raw milk and with traditional techniques and tools, from autochthonous breeds reared under an extensive system. The effects of the month of production on gross composition, MUFA, PUFA, PUFA-\u3c96, PUFA-\u3c93, \u3b1-tocopherol, retinol, cholesterol, TPC, TEAC, and GHIC were evaluated. In CP, CLA, TPC, and GHIC were higher in April than in February. CdM showed higher values in terms of fat, saturated fatty acids, PUFA-\u3c93, \u3b1-tocopherol, TEAC, and GHIC in May than in February and September, while low values in terms of protein, moisture, and CLA were found. In VVB, MUFA, PUFA-\u3c96, and \u3b1-tocopherol increased in June compared with April; conversely, protein, FRAP, and TEAC were higher in April. In PS, protein, CLA, PUFA, PUFA-\u3c93, \u3b1-tocopherol, and GHIC increased in May compared with January; on the contrary, moisture, NaCl, and TEAC showed high values in January. CN showed higher values in terms of PUFA, PUFA-\u3c96, PUFA-\u3c93, TPC, TEAC, and GHIC in April and June compared with January. It is shown that each cheese is unique and closely linked to the production area. Cheeses produced in the spring months showed a high nutritional quality due to the greatest presence of healthy compounds originating from an extensive feeding system. For the purposes of raising awareness of five historical cheeses of Southern Italy that are less known by consumers, and of restoring dignity to the breeders and producers of these cheeses, we studied their quality in terms of chemical composition, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), conjugated linoleic acid (CLA), PUFA-\u3c96, PUFA-\u3c93, \u3b1-tocopherol, retinol, cholesterol, polyphenol content (TPC), total antioxidant capacity (FRAP and TEAC), and health index (GHIC). Two stretched-curd bovine cheeses, Caciocavallo Palermitano (CP) and Casizolu del Montiferru (CdM), two ovine cheeses, Vastedda della Valle del Bel\uecce (VVB) and Pecorino Siciliano (PS), and one caprine cheese, Caprino Nicastrese (CN), were evaluated. These cheeses are produced in different months, with raw milk from animals reared in an extensive feeding system. In April, the CP cheese showed high values for CLA, TPC, and GHIC, while the CN cheese exhibited high PUFA, PUFA-\u3c96, PUFA-\u3c93, TEAC, and GHIC. In May, the CdM cheese exhibited high content of fat, saturated fatty acids, PUFA-\u3c93, \u3b1-tocopherol, TEAC, and GHIC, while the PS cheese showed high values of protein, CLA, PUFA, PUFA-\u3c93, \u3b1-tocopherol, and GHIC. These measured parameters characterize and distinguish each cheese due to links with numerous factors: Species, breed, feeding system, pasture biodiversity, climate, production technology, traditional tools, and ripening type. It is highlighted that, in general, the highest nutritional quality, linked to the highest presence of healthy compounds, originates from the pasture of cheese production in the spring
Structural basis for inhibition of the histone chaperone activity of SET/TAF-Iß by cytochrome c
Chromatin is pivotal for regulation of the DNA damage process insofar as it influences access to DNA and serves as a DNA repair docking site. Recent works identify histone chaperones as key re- gulators of damaged chromatin’s transcriptional activity. However, understanding how chaperones are modulated during DNA damage response is still challenging. This study reveals that the histone chap- erone SET/TAF-Iß interacts with cytochrome c following DNA damage. Specifically, cytochrome c is shown to be translocated into cell nuclei upon induction of DNA damage, but not upon stimulation of the death receptor or stress-induced pathways. Cytochrome c was found to competitively hinder binding of SET/TAF-Iß to core histones, thereby locking its histone-binding domains and inhibiting its nucle- osome assembly activity. In addition, we have used NMR spectros- copy, calorimetry, mutagenesis, and molecular docking to provide an insight into the structural features of the formation of the complex between cytochrome c and SET/TAF-Iß. Overall, these findings estab- lish a framework for understanding the molecular basis of cyto- chrome c-mediated blocking of SET/TAF-Iß, which subsequently may facilitate the development of new drugs to silence the oncogenic effect of SET/TAF-Iß’s histone chaperone activity
Former Food Products Safety Evaluation : Computer Vision as an Innovative Approach for the Packaging Remnants Detection
Former food products (FFPs) represent a way by which leftovers from the food industry (e.g., biscuits, bread, breakfast cereals, chocolate bars, pasta, savoury snacks, and sweets) are converted into ingredients for the feed industry, thereby keeping food losses in the food chain. FFPs represent an alternative source of nutrients for animal feeding. However, beyond their nutritional value, the use of FFPs in animal feeding implies also safety issues, such as those related to the presence of packaging remnants. These contaminants might reside in FFP during food processing (e.g., collection, unpacking, mixing, grinding, and drying). Nowadays, artificial senses are widely used for the detection of foreign material in food and all of them involve computer vision. Computer vision technique provides detailed pixel-based characterizations of colours spectrum of food products, suitable for quality evaluation. The application of computer vision for a rapid qualitative screening of FFP's safety features, in particular for the detection of packaging remnants, has been recently tested. This paper presents the basic principles, the advantages, and disadvantages of the computer vision method with an evaluation of its potential in the detection of packaging remnants in FFP
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