445 research outputs found

    Ultrasound-assisted extraction of anthocyanins and total phenolic compounds in Vitis vinifera L. 'Tempranillo' winemaking lees

    Get PDF
    Winemaking lees (WL) are the less exploited by-products from the winemaking industry. This by-product is generated after the fermentation of grape must and its composition is variable, although it is mainly made up of lysed yeasts, tartaric acid, colloids, polyphenols and ashes. Of all the compounds that can be found in lees, polyphenols exhibit particularly powerful bioactive properties and their extraction for their reuse in different matrices could be a matter of particular interest.Ultrasound-assisted extraction (UAE) has been used to extract both total anthocyanins (TA) and total phenolic compounds (TPC) from lees from Vitis vinifera L. 'Tempranillo' vinification. The optimization of six extraction variables (% methanol, pH, temperature, amplitude, cycle and ratio solvent:mass) was performed using a Box-Behnken design (BBD) where TA and TPC were considered independent variables. The UAE method that has been developed in this research could be a new rapid and efficient method to extract TPC and, coupled to chromatographic methodologies, identify up to fourteen different anthocyanins from WL. The objective of this study is to determine WL polyphenolic content and its potential for further uses in other procedures aiming to create value from vinification waste

    Septic arthritis of the knee due to Prevotella loescheii following tooth extraction

    Get PDF
    This is a case report of septic arthritis of the knee due to Prevotella loescheii, in a patient with advanced arthrosis. Two weeks beforehand he had undergone a dental root extraction without antibiotic prophylaxis. His knee had become inflamed 48 hours after extraction and he was started on ibuprofen and steroid treatment (prescribed by his primary health care doctor). With a provisional diagnosis of septic arthritis, synovial fluid was taken for study. Antimicrobial therapy was commenced with amoxicillin/clavulanic acid and the patient progressed satisfactorily. Prevotella loescheii was identified by anaerobic culture. A site of origin for the infection was never found. Joint infection is generally secondary to haematogenous dissemination of bacteria from habitual sites such as odontogenic locations. We suggest that patients with inflammatory arthropathies should be considered as candidates for antibiotic prophylaxis in oral surgery and invasive dental procedures. We suggest, in these cases, the use of antibiotic with spectrum against aerobic and anaerobic bacteria

    Assessment of the Skill of Coupled Physical–Biogeochemical Models in the NW Mediterranean

    Get PDF
    Numerical modeling is a key tool to complement the current physical and biogeochemical observational datasets. It is essential for understanding the role of oceanographic processes on marine food webs and producing climate change projections of variables affecting key ecosystem functions. In this work, we evaluate the horizontalandverticalpatternsoffourstate-of-the-artcoupledphysical–biogeochemical models, three of them already published. Two of the models include data assimilation, physical and/or biological, and two do not. Simulations are compared to the most exhaustive dataset of in situ observations in the North Western Mediterranean, built ad hoc for this work, comprising gliders and conventional CTD surveys and complemented with satellite observations. The analyses are performed both in the whole domain and in four subregions (Catalan Shelf, Ebro Delta, Mallorca Channel, and Ibiza Channel), characterized by a priori divergent primary production dynamics and driving mechanisms. Overall, existing models offer a reasonable representation of physical processes including stratification, surface temperature, and surface currents, but it is shown that relatively small differences among them can lead to large differences in the response of biogeochemical variables. Our results show that all models are able to reproduce the main seasonal patterns of primary production both at the upper layer and at the deep chlorophyll maximum (DCM), as well as the differential behavior of the four subregions. However, there are significant discrepancies in the local variabilityoftheintensityofthewintermixing,phytoplanktonblooms,ortheintensityand depth of the DCM. All model runs show markedly contrasting patterns of interannual phytoplankton biomass in all four subregions. This lack of robustness should dissuade end users from using them to fill gaps in time series observations without assessing their appropriateness. Finally, we discuss the usability of these models for different applications in marine ecology, including fishery oceanography

    Multiple Mechanisms Promote the Retained Expression of Gene Duplicates in the Tetraploid Frog Xenopus laevis

    Get PDF
    Gene duplication provides a window of opportunity for biological variants to persist under the protection of a co-expressed copy with similar or redundant function. Duplication catalyzes innovation (neofunctionalization), subfunction degeneration (subfunctionalization), and genetic buffering (redundancy), and the genetic survival of each paralog is triggered by mechanisms that add, compromise, or do not alter protein function. We tested the applicability of three types of mechanisms for promoting the retained expression of duplicated genes in 290 expressed paralogs of the tetraploid clawed frog, Xenopus laevis. Tests were based on explicit expectations concerning the ka/ks ratio, and the number and location of nonsynonymous substitutions after duplication. Functional constraints on the majority of paralogs are not significantly different from a singleton ortholog. However, we recover strong support that some of them have an asymmetric rate of nonsynonymous substitution: 6% match predictions of the neofunctionalization hypothesis in that (1) each paralog accumulated nonsynonymous substitutions at a significantly different rate and (2) the one that evolves faster has a higher ka/ks ratio than the other paralog and than a singleton ortholog. Fewer paralogs (3%) exhibit a complementary pattern of substitution at the protein level that is predicted by enhancement or degradation of different functional domains, and the remaining 13% have a higher average ka/ks ratio in both paralogs that is consistent with altered functional constraints, diversifying selection, or activity-reducing mutations after duplication. We estimate that these paralogs have been retained since they originated by genome duplication between 21 and 41 million years ago. Multiple mechanisms operate to promote the retained expression of duplicates in the same genome, in genes in the same functional class, over the same period of time following duplication, and sometimes in the same pair of paralogs. None of these paralogs are superfluous; degradation or enhancement of different protein subfunctions and neofunctionalization are plausible hypotheses for the retained expression of some of them. Evolution of most X. laevis paralogs, however, is consistent with retained expression via mechanisms that do not radically alter functional constraints, such as selection to preserve post-duplication stoichiometry or temporal, quantitative, or spatial subfunctionalization

    Asymmetric synthesis of cyclic β-amino carbonyl derivatives by a formal [3 + 2] photocycloaddition

    Full text link
    Herein, a visible-light mediated strategy unlocking a family of cyclic β-amino carbonyl derivatives bearing three contiguous stereogenic centres is introduced. The overall reactivity relies on the performance of the substrate-catalyst complex to assist both the enantiocontrol and the photoredox tasks. This transformation led to an enantioselective [3 + 2] photocycloaddition between coordinated α,β-unsaturated acyl imidazoles and cyclopropylamine derivative

    Almost Periodic and Asymptotically Almost Periodic Solutions of Liénard Equations

    Get PDF
    The aim of this paper is to study the almost periodic and asymptotically almost periodic solutions on (0,+1) of the Li´enard equation x′′ + f(x)x′ + g(x) = F(t), where F : T ! R (T = R+ or R) is an almost periodic or asymptotically almost periodic function and g : (a, b) ! R is a strictly decreasing function. We study also this problem for the vectorial Li´enard equation. We analyze this problem in the framework of general non-autonomous dynamical systems (cocycles). We apply the general results obtained in our early papers [3, 7] to prove the existence of almost periodic (almost automorphic, recurrent, pseudo recurrent) and asymptotically almost periodic (asymptotically almost automorphic, asymptotically recurrent, asymptotically pseudo recurrent) solutions of Li´enard equations (both scalar and vectorial)
    corecore