232 research outputs found

    Modified Gravity at Astrophysical Scales

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    Using a perturbative approach we solve stellar structure equations for low-density (solar-type) stars whose interior is described with a polytropic equation of state in scenarios involving a subset of modified gravity theories. Rather than focusing on particular theories, we consider a model-independent approach in which deviations from General Relativity are effectively described by a single parameter ξ\xi. We find that for length scales below those set by stellar General Relativistic radii the modifications introduced by modified gravity can affect the computed values of masses and radii. As a consequence, the stellar luminosity is also affected. We discuss possible further implications for higher density stars and observability of the effects before described.Comment: 12 pages, 7figures, matches published versio

    Identification of peptides from edible silkworm pupae (Bombyx mori) protein hydrolysates with antioxidant activity

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    Silkworm (Bombyx mori) pupae is a by-product from the silk industry which is rich in protein. Hydrolysates from silkworm pupae generated using Alcalase®, Prolyve®, Flavourzyme® and Brewers Clarex® proteolytic prepa- rations were characterised. The antioxidant activity of the hydrolysates was investigated using in vitro antioxi- dant assays and an in situ assay for reactive oxygen species (ROS) reduction using hepatic HepG2. Overall, Alcalase and Prolyve hydrolysates had highest scavenging activities, however, Flavourzyme and Brewers Clarex hydrolysates had enhanced ferric reducing antioxidant power (FRAP) activity compared to the other samples. Furthermore, the Flavourzyme hydrolysate significantly reduced ROS by 40% compared to untreated control HepG2 cells. Peptides identified by LC-MS/MS were synthetised and then tested for their in vitro and in situ antioxidant activity. Peptides SWFVTPF and NDVLFF showed highest antioxidant activity (ROS reduction, su- peroxide dismutase (SOD) expression and glutathione (GSH) production activity) in HepG2 cells, and therefore may have potential as natural antioxidants

    Current knowledge on the extraction, purification, identification and validation of bioactive peptides from seaweed

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    peer-reviewedSeaweed (macroalgae) is considered as a sustainable bioresource rich in high-quality nutrients such as protein. Seaweed protein can be used as an alternative to other protein sources. Furthermore, these proteins are natural reservoirs of bioactive peptides (BAPs) associated with various health benefits such as antioxidant, antihypertensive and antidiabetic activities. However, seaweed derived BAPs remain underexploited due to challenges which arise during protein extraction from algal biomass. Coupled with this, limited proteomic information exists regarding certain seaweed species. This review highlights the current state of the art of seaweed protein extraction techniques, e.g., liquid, ultrasound, microwave, pulsed electric field and high hydrostatic pressure assisted extraction. The review also focuses on the enzymatic hydrolysis of seaweed proteins and characterisation of the resultant hydrolysates/peptides using electrophoretic and chromatographic techniques. This includes reference to methods employed for separation, fractionation and purification of seaweed BAPs, as well as the methodologies used for identification, e.g., analysis by mass spectrometry. Furthermore, a bioinformatics or in silico approach to aid discovery of seaweed BAPs is discussed herein. Based on the information available to date, it is suggested that further research is required in this area for the development of seaweed BAPs for nutraceutical applications

    Interfacial/foaming properties and antioxidant activity of a silkworm (Bombyx mori) pupae protein concentrate

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    The current consumer demand for healthier diets, the growing interest in the search for new sources of protein, and the desire to reduce the negative effects on the environment have increased interest in the study of insect proteins. The present study focused on the technofunctional characteristics (interfacial and foaming properties) and the in-vitro antioxidant activity of a protein concentrate obtained from silkworm (Bombyx mori) pupae (SPC). The isoelectric point of the SPC was close to pH 4.0–5.0 as determined by protein solubility and z potential analysis. Given that the SPC had solubilities of ~50% and z potentials of ~20 mV at pH 2.0 and 8.0, it was decided to further study SPC properties at these pH values. The supernatant obtained after adjustment of SPC to pH 8.0 showed higher (p < 0.05) antioxidant activity than that at pH 2.0 when analysed by the ferric reducing antioxidant power (FRAP) assay (168.0 ± 3.0 V. 43.5 ± 8.1 μmol Trolox Eq. ·g−1 protein). However, no significant differences in antioxidant activity were found between pH 2.0 and 8.0 when using the oxygen radical absorbance capacity (ORAC) assay (1826.0 ± 131.9 vs. 1659.2 ± 46.8 μmol Trolox Eq. g−1 protein). The interfacial properties of SPC were determined at pH 2.0 and 8.0 during protein adsorption and after reaching the pseudo equilibrium state by means of dilatational and interfacial shear rheology following by foaming capacity and stability analyses. Faster adsorption kinetic values were obtained at pH 8 ( Vs. at pH 2.0). However, lower kinetic values at pH 2.0 increased the elastic behaviour of the viscoelastic interfacial film formed (E's ⁓ 30 mN/m at pH 2.0 V. E's ⁓ 20 mN/m at pH 8.0), which can be related with the higher protein sizes found at pH 2.0. These rearrangements of the SPC components appeared to increase its foaming capacity, whereas the foaming capacity of SPC adjusted to pH 8.0 was minimal.University of Seville for the VPPI-US grant (Ref.-II.5)Ministerio de Ciencia, Innovación y Universidades (España) / FEDER RTI2018-097100-B-C2

    Trophic and tectonic limits to the global increase of marine invertebrate diversity

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    9 pages, 3 figures, supplementary material https://doi.org/10.1038/s41598-017-16257-wThe marine invertebrate fossil record provides the most comprehensive history of how the diversity of animal life has evolved through time. One of the main features of this record is a modest rise in diversity over nearly a half-billion years. The long-standing view is that ecological interactions such as resource competition and predation set upper limits to global diversity, which, in the absence of external perturbations, is maintained indefinitely at equilibrium. However, the effect of mechanisms associated with the history of the seafloor, and their influence on the creation and destruction of marine benthic habitats, has not been explored. Here we use statistical methods for causal inference to investigate the drivers of marine invertebrate diversity dynamics through the Phanerozoic. We find that diversity dynamics responded to secular variations in marine food supply, substantiating the idea that global species richness is regulated by resource availability. Once diversity was corrected for changes in food resource availability, its dynamics were causally linked to the age of the subducting oceanic crust. We suggest that the time elapsed between the formation (at mid-ocean ridges) and destruction (at subduction zones) of ocean basins influences the diversity dynamics of marine invertebrates and may have contributed to constrain their diversificationP.C. was supported by a Ramón y Cajal contract from the Spanish Government. This research was funded by the Spanish Government through research grant CTM2014-54926-R.Peer Reviewe

    Enzyme-assisted release of antioxidant peptides from porphyra dioica conchocelis

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    peer-reviewedThe conchocelis life cycle stage of P. dioica represents an unexplored source of bioactive compounds. The aim of this study was to generate and characterise, for the first time, hydrolysates of conchocelis using a specific combination of proteases (Prolyve® and Flavourzyme®). Hydrolysate molecular mass distribution and free amino acid contents were assessed, and the antioxidant activity was determined using a range of in vitro assays. The protein content and the total amino acid profiles of conchocelis were also studied. Conchocelis contained ~25% of protein (dry weight basis) and had a complete profile of essential amino acids. Direct sequential enzymatic treatment modified the profile of the generated compounds, increasing the amount of low molecular weight peptides (<1 kDa). There was a significant improvement in the antioxidant activity of the hydrolysates compared with the control (up to 2.5-fold), indicating their potential as a novel source of antioxidant ingredients

    Kappa free light chains is a valid tool in the diagnostics of MS: A large multicenter study

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    To validate kappa free light chain (KFLC) and lambda free light chain (LFLC) indices as a diagnostic biomarker in multiple sclerosis (MS).We performed a multicenter study including 745 patients from 18 centers (219 controls and 526 clinically isolated syndrome (CIS)/MS patients) with a known oligoclonal IgG band (OCB) status. KFLC and LFLC were measured in paired cerebrospinal fluid (CSF) and serum samples. Gaussian mixture modeling was used to define a cut-off for KFLC and LFLC indexes.The cut-off for the KFLC index was 6.6 (95% confidence interval (CI) = 5.2-138.1). The cut-off for the LFLC index was 6.9 (95% CI = 4.5-22.2). For CIS/MS patients, sensitivity of the KFLC index (0.88; 95% CI = 0.85-0.90) was higher than OCB (0.82; 95%CI = 0.79-0.85; p < 0.001), but specificity (0.83; 95% CI = 0.78-0.88) was lower (OCB = 0.92; 95% CI = 0.89-0.96; p < 0.001). Both sensitivity and specificity for the LFLC index were lower than OCB.Compared with OCB, the KFLC index is more sensitive but less specific for diagnosing CIS/MS. Lacking an elevated KFLC index is more powerful for excluding MS compared with OCB but the latter is more important for ruling in a diagnosis of CIS/MS

    Rol de conjugados proteína-polisacáridos en la estabilidad de emusliones procesadas con proteína de suero de leche

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    Recientemente las propiedades bioactivas de los distintos alimentos han despertado un gran interés. En el presente trabajo se pretende establecer una relación entre propiedades bioactivas de emulsiones y la estabilidad de éstas. Para preparar estas emulsiones, se ha empleado proteína de suero de leche conjugada con carragenano, el cual es un hidrocoloide conocido por su capacidad de formar conjugados con proteínas, así como de aumentar la viscosidad de los sistemas donde está presente. Tras establecer una relación tiempo/temperatura óptima para la conjugación. Tras llevar a cabo un diseño de experimento, se seleccionaron cuatro sistemas para establecer aquel que mantuviera las propiedades bioactivas y funcionales en una mejor proporción. Los resultados obtenidos ayudan a determinación de una concentración óptima de proteína de suero de leche y de carragenano (polisacárido) en sistemas las emulsiones empleadas. Además de las propiedades bioactivas logradas con este sistema, estos resultados son fundamentales para la posible encapsulación de ingredientes activos en alimentos funcionales

    Four-year safety and effectiveness data from patients with multiple sclerosis treated with fingolimod : The Spanish GILENYA registry

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    Objective To describe the profile of patients with multiple sclerosis (MS) treated with fingolimod in Spain and to assess the effectiveness and safety of fingolimod after 4 years of inclusion in the Spanish Gilenya Registry. Methods An observational, retrospective/prospective, multicenter case registry, including all patients with relapsing-remitting MS (RRMS) starting treatment with fingolimod in 43 centers in Spain. Analyses were performed in the overall population and in subgroups according to prior disease-modifying therapy (DMT): glatiramer acetate/interferon beta-1 (BRACE), natalizumab, other treatment, or naïve. Results Six hundred and sixty-six evaluable patients were included (91.1% previously treated with at least one DMT). The mean annualized relapse rate (ARR) prior to fingolimod was 1.12, and the mean EDSS at fingolimod initiation was 3.03. Fingolimod reduced the ARR by 71.4%, 75%, 75.5%, and 80.3%, after 1, 2, 3 and 4 years, respectively (p<0.001). This significant reduction in the ARR continuedto be observed in all subgroups. After 4 years, the EDSS showed a minimal deterioration, with the EDSS scores from year 1 to year 4 remaining mostly stable. The percentage of patients without T1 Gd+ lesions progressively increased from 45.6% during the year prior to fingolimod initiation to 88.2% at year 4. The proportion of patients free from new/enlarged T2 lesions after 4 years of fingolimod treatment was 80.3%. This trend in both radiological measures was also observed in the subgroups. Adverse events (AEs) were experienced by up to 41.6% of patients (most commonly: lymphopenia [12.5%] and urinary tract infection [3.7%]). Most AEs were mild in severity, 3.6% of patients had serious AEs. Conclusions The patient profile was similar to other observational studies. The results obtained from the long-term use of fingolimod showed that it was effective, regardless of prior DMT, and it had adequate safety results, with a positive benefit-risk balance
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