457 research outputs found

    Fischer-Tropsch synthesis in microchannels

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    Different metallic supports (aluminum foams of 40ppi, honeycomb monolith and micromonolith of 350 and 1180cpsi, respectively) have been loaded with a 20%Co-0.5%Re/γ-Al2O3 catalyst by the washcoating method. Layers of different thicknesses have been deposited onto the metallic supports. The catalytic coatings were characterized measuring their textural properties, adhesion and morphology. These structured catalysts have been tested in the Fischer-Tropsch synthesis (FTS) and compared with a microchannel block presenting perpendicular channels for reaction and cooling. The selectivity depends on the type of support used and mainly on the thickness of the layer deposited. In general, the C5+ selectivity decreased at increasing CO conversion for all of the systems (powder, monoliths, foams and microchannels block). On the other hand, the selectivity to methane increased with the thickness of the catalytic layer due to the higher effective H2/CO ratio over the active sites resulting from the higher diffusivity of H2 compared with CO in the liquid products filling the pores. The C5+ selectivity of the microchannels reactor is higher than that of the structured supports and the powder catalyst.Ministerio de Ciencia e Innovación MAT2006-12386-C05, ENE2009-14522-C0

    Evaluation of sensory parameters of grapes using near infrared spectroscopy

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    [EN] Grape seed and skin sensory parameters are important characteristics in making decisions concerning the optimal harvest time and producing high-quality red wines. The potential of near infrared spectroscopy to determine several sensory parameters of seeds and skins was evaluated. Taste (sourness), texture (astringency, tannic intensity, dryness and hardness), visual (colour) and olfactory (intensity and type of aroma) attributes were considered. Calibration models were performed by modified partial least squares regression. The differences between sensory analysis and NIRS analysis in external validation were lower in the case of seeds; they were between 4.5% for hardness and 8.7% for colour. For the skins, differences in external validation were between 9.8% for tannic intensity and 13.7% for astringency. The results obtained show that NIRS technology has considerable potential for predicting the above sensory attributes

    Sensory evaluation of bitterness and astringency sub-qualities of wine phenolic compounds: synergistic effect and modulation by aromas

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    [EN] Mouthfeel characteristics of wine phenolic compounds (catechin, epicatechin, coumaric acid, caffeic acid, protocatechuic acid and gallic acid) were evaluated by sensory analysis using a Labeled Magnitude Scale for rating the intensity of the perceived sensations. Synergisms on bitterness and on astringent sub-qualities were detected when the phenolic compounds were tested as mixtures in comparison to individual compounds, maintaining the total amount of stimulus constant in all tasted samples. Principal component analysis was applied to observe trends in the data and to indicate relationships between phenolic substances and sensory attributes. It allowed us to easily visualize the synergistic effect discussed above. To our knowledge, this is the first time that astringency synergism between phenolic compounds has been described. This research also shows that wine aromas may modulate the perception of the astringency. In this study, the addition of volatile compounds increased the intensity of the astringent perception of the flavanol solutions and also its persistence

    Determination of phenolic compounds of grape skins during ripening by NIR spectroscopy

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    [EN] The potential of near infrared spectroscopy (NIRS) to determine the content of phenolic compounds in red grapes has been evaluated. The near infrared spectra of intact grapes and grape skins throughout maturity were recorded using a fibre-optic probe and a transport quartz cup, respectively. Reference values of phenolic compounds were obtained by HPLC-DAD-MS. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models for flavanols, flavonols, phenolic acids, anthocyanins and total phenolic compounds. The procedure reported here seems to have an excellent potential for fast and reasonable cost analysis. The results of this work show that the models developed using NIRS technology together with chemometric tools allow the quantification of total phenolic compounds and the families of main phenolic compounds in grape skins throughout maturation. The validation of these models showed the best results for the determination of flavonols (differences between HPLC and NIRS of 7.8% using grapes and 10.7% using grape skins) in the external validation procedure. Good results in the external validation were also obtained for the determination of total phenolic compounds (differences of 11.7% using grapes and 14.7% using grape skins). The best results were generally obtained recording the spectra directly in intact grapes

    Feasibility study on the use of near infrared spectroscopy to determine flavanols in grape seeds

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    [EN] The potential of near infrared spectroscopy to determine the content of flavanols directly recording the infrared spectra of grape seeds has been evaluated. Moreover, the study shows the potential of this technique to obtain qualitative information related to the samples. In this case, the feasibility to discriminate between possible vineyards of origin has also been evaluated. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models in order to predict the content of flavanols. These models have been validated showing differences between 3.5% and 14.3% in the external validation. Moreover, Discriminant Partial Least Squares algorithm was used in the qualitative analysis to distinguish between two possible vineyards of origin and showed a high degree of accuracy. Prediction rates of samples correctly classified with a mean of 95% in internal validation and 97% in external validation were obtained. The procedure reported here seems to have an excellent potential for a fast and reasonably inexpensive analysis of these flavanols in grape seeds and could also be a tool to distinguish between possible vineyards of origin

    Influence of climatic conditions on the phenolic composition of Vitis vinifera L. cv. Graciano

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    [EN] The influence of different climatic conditions on the phenolic composition of grape skins and seeds of Vitis vinifera L. cv. Graciano – an autochthonous cultivar from Rioja and Navarra regions (Spain) – was evaluated during ripening in a separate way. Graciano grapes from two different vineyards with different climatic conditions and from two different vintages (2008 and 2009) were analysed. Clear differences between phenolic maturity pattern of grape skins and seeds were observed. In this context, it may be important to evaluate the phenolic maturity of seeds and skins in a separate way in order to decide the optimal harvest time. It was also noticeable that the effect of vintage (mainly due to changes in climatic conditions) may affect the changes in the phenolic composition of both grape skins and seeds. Although in a lesser extent, the effect of the vineyard was also observable, and it was especially relevant in vintages with irregular climatic conditions such as 2008 vintage. In a second strand, results obtained from the phenolic composition of grape seeds and skins at harvest, oenological parameters at harvest and climate conditions during vegetative stage were evaluated and relationships among the aforementioned variables were revealed

    Influence of 12-week concurrent training on exosome cargo and its relationship with cardiometabolic health parameters in men with obesity

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    [EN] Exosome release varies depending on the physiological state of the cell, so they could play a fundamental role in obesity, the biggest pandemic in today's societies. The beneficial effects that physical activity has both on weight and cardiovascular parameters may be mediated by exosomes released in response to exercise. Thus, we aimed (I) to study the influence of a 12-week CT intervention on exosome cargo modifications in men with obesity and (II) to determine whether changes in exosomes after the intervention were related to changes in cardiometabolic health parameters in our cohorts. An experimental, controlled design was performed in twelve (nine with valid data) adult male obese patients (mean values: 41.6 years old, 97.6 kg and 32.4 kg/m2) who were randomly divided into a control group (n = 4) and a training group (n = 5), which completed 36 sessions of CT (concurrent training) for 12 weeks. Before and after the training period, cardiometabolic health parameters were evaluated and blood samples to measure exosomes and proteins were drawn. No changes were observed in the levels of any exosomal markers and proteins; however, associations of changes between CD81 and both fat mass and weight, Flot-1 and VO2max, HSP70 and both CRP and left ventricle diastolic diameter or CD14 and leptin were found (all p ≤ 0.05). Although the current CT was not able to clearly modify the exosome cargo, a certain medium to large clinical effect was manifested considering the nature of this study. Moreover, the associations found between the promoted changes in cardiometabolic parameters and exosome-carried proteins could indicate a relationship to be considered for future treatments in patients with obesity.SICurrent research activities of D.J.-P. are supported by a grant from the Spanish Ministry of Science and Innovation—MINECO (RYC-2014-16938) and the EXERNET Research Network on Exercise and Health in Special Populations (DEP2005-00046/ACTI). Technology Fund—FEDER funds (R&D&I Operating Program) was used by and for the benefit of companies (Technology Fund) INNTERCONECTA (BRISA Contract-University of Cádiz). The results of the study are presented clearly, honestly and without fabrication, falsification or inappropriate data manipulation.Biomedical Research Networking Center on Frailty and Healthy Aging (CIBERFES) and FEDER funds from the European Union (CB16/10/00477)

    The JCMT Nearby Galaxies Legacy Survey – XI. Environmental Variations in the Atomic and Molecular Gas Radial Profiles of Nearby Galaxies

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    We present an analysis of the radial profiles of a sample of 43 H I-flux selected spiral galaxies from the Nearby Galaxies Legacy Survey (NGLS) with resolved James Clerk Maxwell Telescope (JCMT) CO J = 3 − 2 and/or Very Large Array (VLA) H I maps. Comparing the Virgo and non-Virgo populations, we confirm that the H i discs are truncated in the Virgo sample, even for these relatively H i-rich galaxies. On the other hand, the H2 distribution is enhanced for the Virgo galaxies near their centres, resulting in higher H2 to H I ratios and steeper H2 and total gas radial profiles. This is likely due to the effects of moderate ram pressure stripping in the cluster environment, which would preferentially remove low-density gas in the outskirts while enhancing higher density gas near the centre. Combined with Hα star formation rate data, we find that the star formation efficiency (SFR/H2) is relatively constant with radius for both samples, but the Virgo galaxies have an ∼40 per cent lower star formation efficiency than the non-Virgo galaxies

    Statistical correlation between flavanolic composition, colour and sensorial parameters in grape seed during ripening

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    [EN] The aim of this work has been to determine the correlations between sensory analysis, colour and content of main flavanols present in seeds. For this, the flavanic composition of grape seeds with different degrees of maturity was analysed by HPLC–DAD-MS and the obtained results were correlated with CIELab colour parameters, perceived colour (C), hardness of the seed (HS), tannic intensity (TI) and astringency (A). Multiple linear regression analysis (MLR) with the variables showing significant correlations (p < 0.05) was also performed. Grape seeds undergo important decreases in the content of catechins and procyanidin oligomers during ripening. Epicatechin-(4-8)-epicatechin-3-O-gallate (B2G) and (−)-epicatechin-3-Ogallate (ECG) are the flavanolic compounds whose contents decrease most. The changes in the phenolic composition accompany changes in TI, A and HS. The total content of flavanols in the seed is not the only factor affecting these attributes, since samples containing higher contents in flavanols can exhibit less astringency and tannic intensity than others with lower ones. The qualitative profile of the seeds is, therefore, also responsible for the sensations elicited in the mouth. A and HS parameters are more affected by the presence of galloylated dimeric procyanidins in the molecule than TI. CIELab colour parameters of seeds have high correlation coefficients with many flavanolic compounds. ECG was the compound most related to these parameters

    Exploring the HIV-1 Rev Recognition Element (RRE)-Rev Inhibitory Capacity and Antiretroviral Action of Benfluron Analogs

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    Human immunodeficiency virus-type 1 (HIV-1) remains one of the leading contributors to the global burden of disease, and novel antiretroviral agents with alternative mechanisms are needed to cure this infection. Here, we describe an exploratory attempt to optimize the antiretroviral properties of benfluron, a cytostatic agent previously reported to exhibit strong anti-HIV activity likely based on inhibitory actions on virus transcription and Rev-mediated viral RNA export. After obtaining six analogs designed to modify the benzo[c]fluorenone system of the parent molecule, we examined their antiretroviral and toxicity properties together with their capacity to recognize the Rev Recognition Element (RRE) of the virus RNA and inhibit the RRE-Rev interaction. The results indicated that both the benzo[c] and cyclopentanone components of benfluron are required for strong RRE-Rev target engagement and antiretroviral activity and revealed the relative impact of these moieties on RRE affinity, RRE-Rev inhibition, antiviral action and cellular toxicity. These data provide insights into the biological properties of the benzo[c]fluorenone scaffold and contribute to facilitating the design of new anti-HIV agents based on the inhibition of Rev function.This research was funded by Generalitat Valenciana of Spain (PROMETEO 2021/036 grant to J.G. and GRISOLIAP/2020/026 contract to M.P.S.), MCIN/AEI/10.13039/501100011033 of Spain and “ERDF A way of making Europe” (grants PID2020-117508RB-I00 to V.M., RTI2021-093935-B-I00 to J.G., PID2021-125978OB-C2 to J.A. and PID2019-109870RB-I00 and CB21/13/00063 to J.M.-P.).S
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