Isoperimetric inequalities in graphs and surfaces

Let M be the set of metric spaces that are either graphs with bounded degree or Riemannian manifolds with bounded geometry. Kanai proved the quasi-isometric stability of several geometric properties (in particular, of isoperimetric inequalities) for the spaces in M. Kanai proves directly these results for graphs with bounded degree; in order to prove the general case, he uses a graph (an ?-net) associated to a Riemannian manifold with bounded geometry. This paper studies the stability of isoperimetric inequalities under quasi-isometries between non-exceptional Riemann surfaces (endowed with their Poincare metrics). The present work proves the stability of the linear isoperimetric inequality for planar surfaces (genus zero surfaces) without the condition on bounded geometry. It is also shown the stability of any non-linear isoperimetric inequality

Effect of a polyphenol–vacuum packaging on lipid deterioration during an 18-month frozen storage of Coho Salmon (Oncorhynchus kisutch)

10 páginas, 3 tablas, 2 figuras.-- The final publication is available at www.springerlink.comA packaging system combining a polyphenolrich film and vacuum (PPRF–VP) was applied to farmed coho salmon (Oncorhynchus kisutch) muscle for an 18- month storage (−18 °C). For it, two different concentrations of polyphenol compounds (namely, p-coumaric and ferulic acids) obtained from a barley husk extract were applied (PPRF–VP conditions) and compared to vacuum packaging without polyphenol presence (vacuum control; VP condition) and to packaging in the absence of vacuum and polyphenols (control; CP condition). The study was addressed to lipid hydrolysis and oxidation development and to lipid changes related to nutritional value. Both PPRF–VP conditions provided an inhibitory effect (p< 0.05) on conjugated diene and fluorescent compound formation in frozen salmon. Compared to CP condition, vacuum packaging (PPRF–VP and VP conditions) led to lower (p<0.05) peroxide and anisidine values and to an inhibitory effect (p<0.05) on α- and γ-tocopherol losses. No effect (p>0.05) of polyphenol presence and vacuum packaging could be inferred on free fatty acid formation (hydrolysis development) and on polyunsaturated fatty acid retention (polyene index assessment). A low rancid odour development was observed in all kinds of fish samples, this being lower (p<0.05) in fish kept under vacuum (PPRF–VP and VP) conditions.Peer reviewe

La influencia del uso de las TICs, los videojuegos y la violencia escolar en el bienestar psicológico (ansiedad y depresión)

El objetivo del presente trabajo es analizar la influencia del uso de las TICs, los videojuegos y la violencia escolar en el bienestar psicológico (ansiedad y depresión). Para ello se ha utilizado una muestra de 35 niños de 7 y 8 años de educación primaria. Los resultados mostraron en primer lugar, que la violencia escolar estuvo correlacionada positiva y significativamente con niveles de depresión y ansiedad. En segundo lugar, el uso de las TICs estuvo correlacionado positiva y significativamente con el uso de videojuegos, y además el uso de videojuegos estuvo positivamente relacionado con el hecho de ser niño y con la subdimensión violencia física directa de violencia escolar. En tercer lugar, se estableció una relación positiva y significativa entre las variables ansiedad y depresión. Por último, existió una relación positiva entre el uso de las TICs y la ansiedad, que fue más intensa en los participantes que usaron en menor medida los videojuegos.<br /

Programa para mejorar competencias digitales, autodeterminación y los componentes semántico y pragmático del lenguaje en personas con Síndrome de Down (SD)

El objetivo del presente trabajo es mejorar las competencias digitales, la autodeterminación y los componentes semántico y pragmático del lenguaje en dos jóvenes con Síndrome de Down (SD). Para ello, se ha evaluado de manera inicial los cuatro ámbitos de interés en ambas participantes, a través de distintos instrumentos estandarizados para posteriormente, diseñar un programa de mejora de competencias digitales, autodeterminación, semántica y pragmática en personas con discapacidad intelectual. Los resultados muestran que ambas participantes mejoraron sus puntuaciones directas y sus medias en los aspectos evaluados, tras la aplicación del programa. Por ello, se puede evidenciar que las participantes experimentaron un desarrollo positivo en los cuatro ámbitos de interés, siendo las competencias digitales el ámbito más desarrollado, seguido por el ámbito de la autodeterminación. También mejoraron los componentes semántico y pragmático del lenguaje, pero en este caso en menor medida.<br /

Skin and subcutaneous mycoses in tilapia (Oreochromis niloticus) caused by fusarium oxyspoum in coinfection with Aeromonas hydrophila

Subcutaneous mycoses in freshwater fish are rare infections usually caused by oomycetes of the genus Saprolegnia and some filamentous fungi. To date, Fusarium infections in farmed fish have only been described in marine fish. Here, we report the presence of Fusarium oxysporum in subcutaneous lesions of Nile tilapia (Oreochromis niloticus). Histopathologic evaluation revealed granuloma formation with fungal structures, and the identity of the etiological agent was demonstrated by morphological and molecular analyses. Some of the animals died as a result of systemic coinfection with Aeromonashydrophila

Lipid Oxidation Inhibition in Frozen Farmed Salmon (Oncorhynchus kisutch ): Effect of Packaging

3 pages, 1 table.Coho salmon (Oncorhynchus kisutch) has recently attracted a great interest as a farmed product. This research focuses on its commercialisation as a frozen product. For it, an advanced storage technology combining vacuum and a polyphenolic rich-film was applied for a 9-months storage period (–18°C). The study was addressed to lipid hydrolysis and oxidation changes and to endogenous antioxidant content in salmon muscle. No effect of packaging conditions could be observed on free fatty acid formation. However, vacuum packaging conditions provided a partial inhibition of primary (peroxide) and secondary (anisidine value) lipid oxidation development; this inhibitory effect was accompanied by a lower tocopherol isomers loss. The employment of a film including polyphenolic compounds led to a partial inhibition of α-tocopherol breakdown and to a lower secondary (anisidine value) and tertiary (fluorescent compound formation) lipid oxidation development. A partial inhibitory effect on lipid oxidation development is concluded for the employment of a polyphenolic compound rich-film packaging when applied to farmed coho salmon.This research was carried out in the frame of the Project No. 2006 CL 0034 (2007–2008), granted by the U. Chile-CSIC Cooperation Program. Coho salmon fish was provided by Aquachile SA (Puerto Montt, Chile).Peer reviewe

Radical scavenging and cellular antioxidant activity of the cocoa shell phenolic compounds after simulated digestion

The cocoa industry generates a considerable quantity of cocoa shell, a by-product with high levels of methylxanthines and phenolic compounds. Nevertheless, the digestion process can extensively modify these compounds’ bioaccessibility, bioavailability, and bioactivity as a consequence of their transformation. Hence, this work’s objective was to assess the influence of simulated gastrointestinal digestion on the concentration of phenolic compounds found in the cocoa shell flour (CSF) and the cocoa shell extract (CSE), as well as to investigate their radical scavenging capacity and antioxidant activity in both intestinal epithelial (IEC-6) and hepatic (HepG2) cells. The CSF and the CSE exhibited a high amount of methylxanthines (theobromine and caffeine) and phenolic compounds, mainly gallic acid and (+)-catechin, which persisted through the course of the simulated digestion. Gastrointestinal digestion increased the antioxidant capacity of the CSF and the CSE, which also displayed free radical scavenging capacity during the simulated digestion. Neither the CSF nor the CSE exhibited cytotoxicity in intestinal epithelial (IEC-6) or hepatic (HepG2) cells. Moreover, they effectively counteracted oxidative stress triggered by tert-butyl hydroperoxide (t-BHP) while preventing the decline of glutathione, thiol groups, superoxide dismutase, and catalase activities in both cell lines. Our study suggests that the cocoa shell may serve as a functional food ingredient for promoting health, owing to its rich concentration of antioxidant compounds that could support combating the cellular oxidative stress associated with chronic disease developmentThis research was funded by the COCARDIOLAC project from the Spanish Ministry of Science and Innovation (RTI 2018-097504-B-I00) and the Excellence Line for University Teaching Staff within the Multiannual Agreement between the Community of Madrid and the UAM (2019–2023). M. Rebollo-Hernanz received funding from the FPU program of the Ministry of Universities for his predoctoral fellowship (FPU15/04238) and a grant for the requalification of the Spanish university system (CA1/RSUE/2021-00656

Influence of potato crisps processing parameters on acrylamide formation and bioaccesibility

A fractional factorial design was used to evaluate the effects of temperature, frying time, blanching treatment and the thickness of potato slices on acrylamide content in crisps. The design was used on freshly harvested and four-month stored potatoes. The critical factors found were temperature and frying time, and the interaction between blanching treatment and slice thickness. Once frying conditions were selected, an acrylamide content of 725 and 1030 mg kg−1 was found for non-stored and 4-month stored tubers, with adequate textural parameters in both cases. The difference in concentration is related to storage conditions, which must be controlled in order to control acrylamide levels. Bioaccesibility studies demonstrated that acrylamide concentration remained at 70%, and reductions took place mainly at the intestinal phase, as a result of reaction with nucleophilic compounds.This research was funded by Fritos Totis SA de CV and CONACyT-Incentives for Research, Technological Development and Innovation Program (conv 2016-232271)S

Slower growth during lactation rescues early cardiovascular and adipose tissue hypertrophy induced by fetal undernutrition in rats

Low birth weight (LBW) and accelerated growth during lactation are associated with cardiometabolic disease development. LBW offspring from rats exposed to undernutrition during gestation (MUN) develops hypertension. In this rat model, we tested if slower postnatal growth improves early cardiometabolic alterations. MUN dams were fed ad libitum during gestation days 1–10, with 50% of the daily intake during days 11–21 and ad libitum during lactation. Control dams were always fed ad libitum. Pups were maintained with their own mother or cross-fostered. Body weight and length were recorded weekly, and breastmilk was obtained. At weaning, the heart was evaluated by echocardiography, and aorta structure and adipocytes in white perivascular fat were studied by confocal microscopy (size, % beige-adipocytes by Mitotracker staining). Breastmilk protein and fat content were not significantly different between groups. Compared to controls, MUN males significantly accelerated body weight gain during the exclusive lactation period (days 1–14) while females accelerated during the last week; length growth was slower in MUN rats from both sexes. By weaning, MUN males, but not females, showed reduced diastolic function and hypertrophy in the heart, aorta, and adipocytes; the percentage of beige-type adipocytes was smaller in MUN males and females. Fostering MUN offspring on control dams significantly reduced weight gain rate, cardiovascular, and fat hypertrophy, increasing beige-adipocyte proportion. Control offspring nursed by MUN mothers reduced body growth gain, without cardiovascular modifications. In conclusion, slower growth during lactation can rescue early cardiovascular alterations induced by fetal undernutrition. Exclusive lactation was a key period, despite no modifications in breastmilk macronutrients, suggesting the role of bioactive components. Our data support that lactation is a key period to counteract cardiometabolic disease programming in LBW and a potential intervention window for the mothe

Investigation of a relationship between twin-disc wear rates and the slipping contact area on R260 grade rail

Twin-disc tests present some limitations for wheel-rail wear characterization such as the obtained contact patch and the error for very low creepages. In this work, creepage phenomena are investigated ranging from 0.12% to 2.45%. To improve the fitting of experimental tests with the theoretical adhesion curve, a modification of the FASTSIM algorithm is proposed. A linear correlation has been found between wear and the slip area including the non-linear zone. Normalized weight losses and wear rates are similar for all tested creepages. Applying this relationship, identified for delaminative wear by surface and metallographic characterization, it is possible to calculate wear for low creepages at wheel-rail contact from twin-disc tests, which should be close to the satu- ration of the friction coefficient