2,642 research outputs found

    Wood-plastic composite based on post-consumer HDPE and vermiculite / Compósito madeira-plástico à base de HDPE pós-consumo e vermiculita

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    In this work, wood plastic-composites (WPCs) were prepared by the incorporation of vermiculite in the post-consumer HDPE. The processing of WPCs with different clay contents (2, 5 and 10% by weight) was carried out in a mono-extruder. The specimens were obtained by compression and characterized by density (ASTM D792), hardness (ASTM D2240) and melt flow index (MFI, ASTM D1238). The composites obtained showed a tendency of increased density and reduced MFI from 5% clay. However, no significant difference in WPC hardness was observed in relation to the matrix. 

    Species pool structure determines the level of generalism of island parasitoid faunas

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    Copyright © 2011 Blackwell Publishing Ltd.AIM To examine whether island parasitoid faunas are biased towards generalists when compared with the mainland and their species pool, and to evaluate the effects of climate, island characteristics and regional factors on the relative proportions of idiobionts (i.e. generalists) and koinobionts (i.e. specialists) of two parasitic wasp families, Braconidae and Ichneumonidae. LOCATION Seventy-three archipelagos distributed world-wide. METHODS We used data on the distribution and biology obtained from a digital catalogue and several literature sources. We related level of generalism, measured as the ratio between the number of idiobiont and koinobiont species, to climatic, physiographic and regional factors using generalized linear models. We compared models by means of Akaike weighting, and evaluated the spatial structure of their residuals. We used partial regressions to determine whether the final models account for all latitudinal structure in the level of generalism. RESULTS Islands host comparatively more idiobionts than continental areas. Although there is a latitudinal gradient in the level of generalism of island faunas correlating with both environmental factors and island characteristics, the most important determinant of island community structure is their source pool. This effect is stronger for ichneumonids, where generalism is higher in the Indomalayan region, arguably due to the higher diversity of endophytic hosts in its large rain forests. MAIN CONCLUSIONS The level of generalism of island parasitoid faunas is largely constrained by regional factors, namely by the structure of the species pool, which emphasizes the importance of including regional processes in our understanding of the functioning of ecological communities. The fact that generalist species are more predominant in islands with a large cover of rain forests pinpoints the importance of the indirect effects of ecological requirements on community structure, highlighting the complex nature of geographical gradients of diversity

    A model of diffuse Galactic Radio Emission from 10 MHz to 100 GHz

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    Understanding diffuse Galactic radio emission is interesting both in its own right and for minimizing foreground contamination of cosmological measurements. Cosmic Microwave Background experiments have focused on frequencies > 10 GHz, whereas 21 cm tomography of the high redshift universe will mainly focus on < 0.2 GHz, for which less is currently known about Galactic emission. Motivated by this, we present a global sky model derived from all publicly available total power large-area radio surveys, digitized with optical character recognition when necessary and compiled into a uniform format, as well as the new Villa Elisa data extending the 1.4 GHz map to the entire sky. We quantify statistical and systematic uncertainties in these surveys by comparing them with various global multi-frequency model fits. We find that a principal component based model with only three components can fit the 11 most accurate data sets (at 10, 22, 45 & 408 MHz and 1.4, 2.3, 23, 33, 41, 61, 94 GHz) to an accuracy around 1%-10% depending on frequency and sky region. Both our data compilation and our software returning a predicted all-sky map at any frequency from 10 MHz to 100 GHz are publicly available at http://space.mit.edu/home/angelica/gsm .Comment: Accuracy improved with 5-year WMAP data. Our data, software and new foreground-cleaned WMAP map are available at https://ascl.net/1011.01

    Metal-sensitive and thermostable trypsin from the crevalle jack (Caranx hippos) pyloric caeca: purification and characterization

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    Background: Over the past decades, the economic development and world population growth has led to increased for food demand. Increasing the fish production is considered one of the alternatives to meet the increased food demand, but the processing of fish leads to by-products such as skin, bones and viscera, a source of environmental contamination. Fish viscera have been reported as an important source of digestive proteases with interesting characteristics for biotechnological processes. Thus, the aim of this study was to purify and to characterize a trypsin from the processing by-products of crevalle jack (Caranx hippos) fish.Results: A 27.5 kDa trypsin with N-terminal amino acid sequence IVGGFECTPHVFAYQ was easily purified from the pyloric caeca of the crevalle jack. Its physicochemical and kinetic properties were evaluated using N-alpha-benzoyl-(DL)-arginine-p-nitroanilide (BApNA) as substrate. in addition, the effects of various metal ions and specific protease inhibitors on trypsin activity were determined. Optimum pH and temperature were 8.0 and 50 degrees C, respectively. After incubation at 50 degrees C for 30 min the enzyme lost only 20% of its activity. K-m, k(cat), and k(cat)/K-m values using BApNA as substrate were 0.689 mM, 6.9 s(-1), and 10 s(-1) mM(-1), respectively. High inhibition of trypsin activity was observed after incubation with Cd2+, Al3+, Zn2+, Cu2+, Pb2+, and Hg2+ at 1 mM, revealing high sensitivity of the enzyme to metal ions.Conclusions: Extraction of a thermostable trypsin from by-products of the fishery industry confirms the potential of these materials as an alternative source of these biomolecules. Furthermore, the results suggest that this trypsin-like enzyme presents interesting biotechnological properties for industrial applications.Financiadora de Estudos e Projetos (FINEP/RECARCINE)Petroleo do Brasil S/A (PETROBRAS)Secretaria Especial de Aquicultura e Pesca (SEAP/PR)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundacao de Apoio a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE)Univ Fed Pernambuco, Lab Enzimol LABENZ, Dept Bioquim CCB, BR-50670910 Recife, PE, BrazilUniv Fed Pernambuco, LIKA, BR-50670910 Recife, PE, BrazilUniversidade Federal de São Paulo, Dept Biofis, Escola Paulista Med, BR-04044020 São Paulo, BrazilUniv Fed Pernambuco, Lab Glicoprot, Dept Bioquim CCB, BR-50670910 Recife, PE, BrazilUniversidade Federal de São Paulo, Dept Biofis, Escola Paulista Med, BR-04044020 São Paulo, BrazilWeb of Scienc

    Dietary phytase effects on copper requirements of broilers

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    Information on the availability of Cu from plant feedstuffs for broilers in the presence of phytase is scarce. The present research has been conducted with the objective of evaluating the Cu requirements of broilers when fed corn-soy diets with or without phytase. A total of 640 one-day-old male Cobb x Cobb 500, allocated into 80 battery cages with 8 chicks in each, were fed a low Cu content diet (formulated with 8.58 ± 0.21 mg/kg Cu) without phytase from placement to day 7. Starting on day 8, battery cages were distributed into a 2 × 5 factorial arrangement (phytase-added diets X 5 with graded increases of supplemental Cu) until day 28. Feeding treatments (feeds added or not with phytase and 5 graded increases of Cu) were randomly distributed with 8 cages of 8 chicks. The basal non-supplemented feeds were formulated with corn and soybean meal (SBM) without any other significant Cu contributors. Supplemental Cu was from laboratory-grade Cu sulfate pentahydrate (CuSO5H20) which was increasingly added to the feeds. Phytase was added in excess to the producer recommendation (2,500 FYT) and had average analyzed values of 2,768 ± 135.2 FYT/kg whereas analyzed Cu values were: 8.05 ± 0.25, 11.25 ± 0.15, 14.20 ± 0.40, 16.55 ± 0.05, and 19.45 ± 0.45 mg/kg. Statistics were conducted using linear and quadratic polynomial regression models. No interactions occurred between dietary Cu and phytase (p &gt; 0.05) for any response and no effects were found for the individual factors (phytase or dietary Cu) for Ht, Hb, varus, valgus, rotated tibia, and tibia breaking strength, as well as for Cu contents in breast, gastrocnemius tendon, and kidney (p &gt; 0.05). However, the phytase-added diets led to higher BWG, lower FCR, and increased ileal digestible Cu (p &lt; 0.05). The gradual increase in dietary Cu produced linear increases in Cu content in livers, as well as in excreta and retention (p &lt; 0.05). Supplementing phytase at levels expected to maximize phytate degradation was demonstrated to improve BWG and FCR; however, no effects were observed when dietary Cu was increased to a maximum of 19.45 mg/kg. An increase of 8.8% in ileal digestible Cu was observed when birds were fed phytase

    Perillyl alcohol in Solid Lipid Nanoparticles (SLN-PA): Cytotoxicity and antitumor potential in sarcoma 180 mice model

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    Cancer is a group of diseases characterized by the uncontrolled growth of cells. These cells invade organs and tissues by extension or direct dissemination and can spread to other regions of the body. Nanomedicine offers many possibilities to prevent the spread of cancer tissue and help cure the disease. In this work, solid lipid nanoparticles (SLN) were used to encapsulate perillyl alcohol (PA), a volatile monoterpene with proven anticancer activity. Encapsulation of PA into SLN (SLN-PA) is expected to promote controlled release, increase PA bioavailability, and impair the volatility of the monoterpene. SLN-PA prepared by high-shear homogenization showed average particle diameter around 254 nm, polydispersity index ~ 0.35, zeta potential ~ -14.7 mV, and encapsulation efficiency 84.6%. Scanning electron microscope analysis revealed a decrease in crystallinity, suggesting the encapsulation of PA in the SLN, confirming the spherical shape and the loading of the monoterpene in the SLN. In vitro cytotoxicity assays against murine fibroblasts (L929) showed that SLN-PA in both treated doses did not induce any cytotoxicity on non-tumoral cells. In vivo antitumor effect of the SLN-PA was evaluated in sarcoma 180-transplanted mice. The in vivo results demonstrated a significant tumor inhibition rate of 51.76 and 54.49% via intraperitoneal application of SLN-PA at doses of 100 and 200 mg/kg/day (p < 0.05), respective when compared to the negative control (dimethyl sulfoxide). Adverse side effects of SLN-PA were not noticed in the liver, the kidney, or spleen tissue. The developed SLN-PA can be considered as a safe approach for site-specific antitumor effect in vivo, reinterpreting new nanoparticles- based cancer therapy.This work was supported by the Banco do Nordeste (grant FUNDECI/2016.0015), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Apoio à Pesquisa e à Inovação Tecnológica do Estado de Sergipe (Fapitec) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Eliana B. Souto would like to acknowledge the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) for the project UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

    Morte súbita e angina vasoespástica

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    Variant angina is defined by chest pain occurring at rest associated with transitory ST segment elevation on ECG, and is caused by a spasm of a coronary artery. Frequently, variant angina is associated with atherosclerotic coronary obstruction and patients with normal coronary arteries are rare. Patients with variant angina and normal coronary arteries have good prognosis, and the development of ventricular arrhythmias or sudden death is rare. The authors present two cases of sudden cardiac death in patients with variant angina and normal coronary arteries

    Silver nanoparticles-composing alginate/gelatine hydrogel improves wound healing in vivo

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    Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430450 nm in the ultraviolet-visible (UVVis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FTIR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.This research received funding from the Coordenação Aperfeiçoamento de Pessoal de Nivel Superior (CAPES), Fundação de Amparo à Pesquisa do Estado de Sergipe (FAPITEC), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, #443238/2014-6, #470388/2014-5), and from the Portuguese Science and Technology Foundation (FCT) projects M-ERA-NET/0004/2015 (PAIRED) and UIDB/04469/2020 (strategic fund).info:eu-repo/semantics/publishedVersio
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