1,128 research outputs found

    Magnetically modified Posidonia oceanica biomass as an adsorbent for organic dyes removal

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    Magnetically modified Posidonia oceanica sea grass dead biomass was employed as an adsorbent of organic dyes. The adsorption of seven water-soluble organic dyes was characterized using Langmuir adsorption model. The highest calculated maximum adsorption capacity was found for Bismarck brown Y (233.5 mg g-1), while the lowest capacity value was obtained for safranin O (88.1 mg g-1). The adsorption processes followed the pseudo-second-order kinetic model and the thermodynamic studies indicated spontaneous and endothermic adsorption

    Magnetic Properties of Ni-Fe Nanowire Arrays: Effect of Template Material and Deposition Conditions

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    The objective of this work is to study the magnetic properties of arrays of Ni-Fe nanowires electrodeposited in different template materials such as porous silicon, polycarbonate and alumina. Magnetic properties were studied as a function of template material, applied magnetic field (parallel and perpendicular) during deposition, wire length, as well as magnetic field orientation during measurement. The results show that application of magnetic field during deposition strongly influences the c-axis preferred orientation growth of Ni-Fe nanowires. The samples with magnetic field perpendicular to template plane during deposition exhibits strong perpendicular anisotropy with greatly enhanced coercivity and squareness ratio, particularly in Ni-Fe nanowires deposited in polycarbonate templates. In case of polycarbonate template, as magnetic field during deposition increases, both coercivity and squareness ratio also increase. The wire length dependence was also measured for polycarbonate templates. As wire length increases, coercivity and squareness ratio decrease, but saturation field increases. Such magnetic behavior (dependence on template material, magnetic field, wire length) can be qualitatively explained by preferential growth phenomena, dipolar interactioComment: 26 pages, 7 figures, 5 Tables Submitted to Physical Review

    A guide to the use of bioassays in exploration of natural resources

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    This publication is based upon work from COST Action CA18238 (Ocean4Biotech), supported by COST (European Cooperation in Science and Technology) program . Funding Information: Research of Dina Simes was funded by the Portuguese National Funds from FCT—Foundation for Science and Technology , through projects UIDB/04326/2020 , UIDP/04326/2020 and LA/P/0101/2020 and AAC n° 41/ALG/2020 - Project n° 072583 – NUTRISAFE. Funding Information: Research of Evita Strode was supported by ERDF post-doctoral research grant 1.1.1.2/16/I/001 (application No 1.1.1.2/VIAA/3/19/465). Funding Information: Susana P. Gaudêncio: This work is financed by national funds from FCT - Fundação para a Ciência e a Tecnologia , I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences - UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy - i4HB . Funding Information: Research of Jerica Sabotič and Nika Janež was supported by Slovenian Research Agency ( J4- 2543 , J4-4555 , P4-0127 , P4-0432 ). Funding Information: Research of Anna Luganini and Giovanna Cristina Varese was financed by the University of Torino (Ricerca Locale) and the European Commission – NextGenerationEU , Project “Strengthening the MIRRI Italian Research Infrastructure for Sustainable Bioscience and Bioeconomy”, code n. IR0000005. Funding Information: Research of David Ezra was supported by The Chief Scientist of the Israeli Ministry of Agriculture and Rural Development (MOARD), grant number 20-02-0122 , and Copia Agro Israel. Publisher Copyright: © 2024 The AuthorsBioassays are the main tool to decipher bioactivities from natural resources thus their selection and quality are critical for optimal bioprospecting. They are used both in the early stages of compounds isolation/purification/identification, and in later stages to evaluate their safety and efficacy. In this review, we provide a comprehensive overview of the most common bioassays used in the discovery and development of new bioactive compounds with a focus on marine bioresources. We present a comprehensive list of practical considerations for selecting appropriate bioassays and discuss in detail the bioassays typically used to explore antimicrobial, antibiofilm, cytotoxic, antiviral, antioxidant, and anti-ageing potential. The concept of quality control and bioassay validation are introduced, followed by safety considerations, which are critical to advancing bioactive compounds to a higher stage of development. We conclude by providing an application-oriented view focused on the development of pharmaceuticals, food supplements, and cosmetics, the industrial pipelines where currently known marine natural products hold most potential. We highlight the importance of gaining reliable bioassay results, as these serve as a starting point for application-based development and further testing, as well as for consideration by regulatory authorities.publishersversionpublishe

    New results from the NA57 experiment

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    We report results from the experiment NA57 at CERN SPS on hyperon production at midrapidity in Pb-Pb collisions at 158 AA GeV/cc and 40 AA GeV/cc. Λ\Lambda, Ξ\Xi and Ω\Omega yields are compared with those from the STAR experiment at the higher energy of the BNL RHIC. Λ\Lambda, Ξ\Xi, Ω\Omega\ and preliminary KS0K_S^0 transverse mass spectra are presented and interpreted within the framework of a hydro-dynamical blast wave model.Comment: 8 pages, 3 figures, contribution to the proceedings of The XXXVIIIth Rencontres de Moriond "QCD and High Energy Hadronic Interactions

    Strange particle production in 158 and 40 AA GeV/cc Pb-Pb and p-Be collisions

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    Results on strange particle production in Pb-Pb collisions at 158 and 40 AA GeV/cc beam momentum from the NA57 experiment at CERN SPS are presented. Particle yields and ratios are compared with those measured at RHIC. Strangeness enhancements with respect to p-Be reactions at the same beam momenta have been also measured: results about their dependence on centrality and collision energy are reported and discussed.Comment: Contribution to the proceedings of the "Hot Quarks 2004" Conference, July 18-24 2004, New Mexico, USA, submitted to Journal of Physics G 7 pages, 5 figure

    Turnover of Carbohydrate-Rich Vegetal Matter During Microaerobic Composting and After Amendment in Soil

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    We propose that microaerobic composting (MC) can be used to decompose vegetal matter with a short turnover time and large carbon (C) recycling potential. We used a novel method for measuring the degree of fragmentation of water-insoluble acid-soluble (WIAS) polysaccharides as a proxy in tracking their relative degree of degradation (i.e., fragmentation endpoint index). Oak leaves and food scrap processed by MC reached a fragmentation end point within 2 weeks. After amending the MC products into soil, the half-life of the polysaccharide residues was ~6–7 times longer (~100–110 days) than that measured during MC. The main products given up during MC were volatile organic acids (VOAs), alcohols and soluble carbohydrates in the compost tea, and CO2. These products accounted for about 2% of the initial carbon in the feedstock. Very small amounts of VOAs, particularly butyric acid, were formed in the amended soil. Based on a residence time of materials in fermentors of 2 weeks, a ~100-m3 capacity MC facility could process 2,000–4,000 metric tons of vegetable matter amended in ten hectares of arable land per year

    Effective Rheology of Bubbles Moving in a Capillary Tube

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    We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

    Kinetic, Isotherm and Thermodynamic Analysis on Adsorption of Cr(VI) Ions from Aqueous Solutions by Synthesis and Characterization of Magnetic-Poly(divinylbenzene-vinylimidazole) Microbeads

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    The magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter 53–212 μm) were synthesized and characterized; their use as adsorbent in removal of Cr(VI) ions from aqueous solutions was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerizing of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterized by N2 adsorption/desorption isotherms, ESR, elemental analysis, scanning electron microscope (SEM) and swelling studies. At fixed solid/solution ratio the various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. Langmuir, Freundlich and Dubinin–Radushkvich isotherms were used as the model adsorption equilibrium data. Langmuir isotherm model was the most adequate. The pseudo-first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The apparent activation energy was found to be 5.024 kJ mol−1, which is characteristic of a chemically controlled reaction. The experimental data fitted to pseudo-second-order kinetic. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The thermodynamic parameters obtained indicated the endothermic nature of adsorption of Cr(VI) ions. Morever, after the use in adsorption, the m-poly(DVB-VIM) microbeads with paramagnetic property were separeted via the applied magnetic force. The magnetic beads could be desorbed up to about 97% by treating with 1.0 M NaOH. These features make the m-poly(DVB-VIM) microbeads a potential candidate for support of Cr(VI) ions removal under magnetic field
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