209 research outputs found

    Biosurfactants produced by Pseudomonas syringae pv tabaci: A versatile mixture with interesting emulsifying properties

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    In recent years, worldwide awareness about environmental concerns has led to an extensive searching for products of natural origin. Biosurfactants (BS), are an attractive alternative to the chemical counterparts. In these sense, this works evaluate for the first time the emulsifying and surface activity of biosurfactants produced by P. syringae pv. tabaci. Chemical characterization revealed that the produced BS extract mostly consisted in a mixture of syringopeptins and arthrofactins. Besides, this sample was able to reduce water surface tension up to 36.89 mN/m. This activity was improved by modifying conditions of pH, temperature and salinity. For instance, the surface tension was reduced up to 29 mN/m when using NaCl 5 % w/w. The BS also exhibited a high emulsifying activity, this being comparable or even superior to that of commercial bioemulsifiers such xanthan, tara and guar gums. A notorious emulsification index, close to 90 %, was exhibited by BS in coconut oil/water mixtures. Moreover, emulsifying activity resulted to be little affected by different operational conditions, thus retaining about 80 % of its emulsificant index in presence of 20 % w/w of NaCl at 80 °C. These findings are indicative of the BS promising properties and its potential as additive in a variety of industrial applications.Fil: Haidar, Carla Nahir. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Pereira, Matheus M.. Universidade Tiradentes; BrasilFil: Lima, Álvaro S.. Universidade Tiradentes; BrasilFil: Nerli, Bibiana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Pellegrini Malpiedi, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentin

    Study of a simplified model for DFIG-based wind turbines

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    In the study of the dynamical behavior of doublyfed induction generators (DFIG), for wind power applications, the use of reduced order models is useful in order to design specific control strategies for wind power plants as well as to obtain lightweight computing simulations. Within this field this paper presents a new dynamic model for wind turbines, based on DFIG, able of representing accurately its behavior during both the steady state and the transient of the grid voltage. As it will be proven this model permits to perform an accurate analysis of the system when there is a voltage dip in the grid. In the following a theoretical study of this model will be carried out and the accuracy of its performance will be tested under different conditions, by means of PSCAD/EMTDC simulations, in order to show its reliability. Finally the reliability of the simplified model will be tested in a scaled experimental setup.Peer ReviewedPostprint (published version

    Validity of the Néel-Arrhenius model for highly anisotropic CoxFe3−xO4 nanoparticles

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    We report a systematic study on the structural and magnetic properties of CoxFe3−xO4 magnetic nanoparticles with sizes between 5 and 25 nm, prepared by thermal decomposition of Fe(acac)3 and Co(acac)2. The large magneto-crystalline anisotropy of the synthesized particles resulted in high blocking temperatures (42 K < TB < 345 K for 5 < d < 13 nm) and large coercive fields (HC ≈ 1600 kA/m for T = 5 K). The smallest particles (⟨d⟩=5 nm) revealed the existence of a magnetically hard, spin-disordered surface. The thermal dependence of static and dynamic magnetic properties of the whole series of samples could be explained within the Neel–Arrhenius relaxation framework by including the thermal dependence of the magnetocrystalline anisotropy constant K1(T), without the need of ad-hoc corrections. This approach, using the empirical Brükhatov-Kirensky relation, provided K1(0) values very similar to the bulk material from either static or dynamic magnetic measurements, as well as realistic values for the response times (τ0 ≈ 10−10s). Deviations from the bulk anisotropy values found for the smallest particles could be qualitatively explained based on Zener's relation between K1(T) and M(T).This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO, Project Nos. MAT2010-19326 and MAT2013-42551).Peer Reviewe

    Application of Nanostructured Carbon-Based Electrochemical (Bio)Sensors for Screening of Emerging Pharmaceutical Pollutants in Waters and Aquatic Species: A Review

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    Pharmaceuticals, as a contaminant of emergent concern, are being released uncontrollably into the environment potentially causing hazardous effects to aquatic ecosystems and consequently to human health. In the absence of well-established monitoring programs, one can only imagine the full extent of this problem and so there is an urgent need for the development of extremely sensitive, portable, and low-cost devices to perform analysis. Carbon-based nanomaterials are the most used nanostructures in (bio)sensors construction attributed to their facile and well-characterized production methods, commercial availability, reduced cost, high chemical stability, and low toxicity. However, most importantly, their relatively good conductivity enabling appropriate electron transfer rates—as well as their high surface area yielding attachment and extraordinary loading capacity for biomolecules—have been relevant and desirable features, justifying the key role that they have been playing, and will continue to play, in electrochemical (bio)sensor development. The present review outlines the contribution of carbon nanomaterials (carbon nanotubes, graphene, fullerene, carbon nanofibers, carbon black, carbon nanopowder, biochar nanoparticles, and graphite oxide), used alone or combined with other (nano)materials, to the field of environmental (bio)sensing, and more specifically, to pharmaceutical pollutants analysis in waters and aquatic species. The main trends of this field of research are also addressed.This work was financially supported by: projects UID/QUI/50006/2019 and PTDC/ASP-PES/29547/2017 (POCI-01-0145-FEDER-029547) funded by FEDER funds through the POCI and by National Funds through FCT - Foundation for Science and Technology. This proposal was also subsidized by the Brazilian agencies CNPq (Proc. 420261/2018-4) and CAPES (Proc. 88881.140821/2017-01; Finance code 001). F.W.P. Ribeiro acknowledges funding provided by FUNCAP-BPI (Proc. BP3-0139-00301.01.00/18). Acknowledgments T.M.B.F. Oliveira thanks the UFCA’s Pro-Rectory of Research and Innovation for initiating his investigations. F.W.P. Ribeiro thanks the CNPq (proc. 406135/2018-5) and all support provided by the UFCA‘s Pro-Rectory of Research and Innovation. A.N. Correia thanks the CNPq (proc. 305136/2018-6).info:eu-repo/semantics/publishedVersio

    New edible coatings composed of galactomannans and collagen blends to improve the postharvest quality of fruits: influence on fruits gas transfer rate

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    The objective of this work was to produce new edible coatings, based on a mixture of galactomannans from novel sources (seeds of Adenanthera pavonina and Caesalpinia pulcherrima), collagen and glycerol, and to determine their influence in gas transfer rates when they are applied on mangoes and apples. The first part of the work consisted in obtaining coating solutions with the convenient values of wettability for each fruit; such coating solutions were then characterized in terms of their permeability (to CO2, O2 and water vapour), mechanical properties, colour and opacity. Gas transfer rates from mangoes coated with a solution of A. pavonina galactomannan (0.5%), collagen (1.5%) and glycerol (1.5%) were compared with those of mangoes without coating: 28% less O2 consumption and 11% less CO2 production were observed in coated mangoes. The same procedure was performed in apples (in this case using C. pulcherrima galactomannan (0.5%), collagen (1.5%) and no glycerol); the CO2 production and the O2 consumption was approximately 50% lower in apples with coating than in apples without coating. The results suggest that these coatings can reduce gas transfer rates in these fruits, and can be therefore important tools to extend their shelf life.The author A.M. Lima was the recipient of fellowship from ALFA VALNATURA Project of the Europe Aid Cooperation Office, M.A.Cerqueira is recipient of a fellowship from Fundação para a Ciência e Tecnologia (FCT, SFRH/BD/23897/2005) and B.W.S. Souza is a recipient of a fellowship from the Coordenação Aperfeiçoamento dePessoal de Nível Superior, Brazil (Capes, Brazil)

    Design and development of an Automatic Optical Inspection (AOI) system support based on digital manufacturing

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    Visual inspection of components, subassemblies and final products is an essential step to ensure the quality control of ready-to-market electronic components. In many manufacturing plants, including Bosch Car Multimedia S.A., typically automated systems for automatic optical inspection (AOI) are implemented at several workstations to perform visual verification and validation in between critical production tasks. At Bosch Car Multimedia S.A., the AOI system includes a metallic support frame that accommodates a series of components for the function of AOI. The support frame is attached to a robotic arm for controlled movement. As the AOI is a rather fast-moving process, deformation of components may occur during monitoring due to the high acceleration of the robotic arm while operating. In addition to this issue, the existent AOI system includes a high number of components and connections which increase complexity for assembly and disassembly operations. This paper presents the redesign for enhanced performance and functionality of a AOI metallic support frame by resourcing to the generative design (GD) exploration method. Furthermore, additive manufacturing technology, based in selective laser sintering (SLS) of polymeric powders, was used for the production of a new lightweight and reliable version of an AOI support frame. The alternative AOI support frame configuration consists of a single consolidated polymeric component that enabled an overall weight decrease above 30% and a reduction of main components and total number of parts of approximately 89% and ~77%, respectively.FEDER - Federación Española de Enfermedades Raras(undefined)European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 039479

    (Bio)Sensing Strategies Based on Ionic Liquid-Functionalized Carbon Nanocomposites for Pharmaceuticals: Towards Greener Electrochemical Tools

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    The interaction of carbon-based nanomaterials and ionic liquids (ILs) has been thoroughly exploited for diverse electroanalytical solutions since the first report in 2003. This combination, either through covalent or non-covalent functionalization, takes advantage of the unique characteristics inherent to each material, resulting in synergistic effects that are conferred to the electrochemical (bio)sensing system. From one side, carbon nanomaterials offer miniaturization capacity with enhanced electron transfer rates at a reduced cost, whereas from the other side, ILs contribute as ecological dispersing media for the nanostructures, improving conductivity and biocompatibility. The present review focuses on the use of this interesting type of nanocomposites for the development of (bio)sensors specifically for pharmaceutical detection, with emphasis on the analytical (bio)sensing features. The literature search displayed the conjugation of more than 20 different ILs and several carbon nanomaterials (MWCNT, SWCNT, graphene, carbon nanofibers, fullerene, and carbon quantum dots, among others) that were applied for a large set (about 60) of pharmaceutical compounds. This great variability causes a straightforward comparison between sensors to be a challenging task. Undoubtedly, electrochemical sensors based on the conjugation of carbon nanomaterials with ILs can potentially be established as sustainable analytical tools and viable alternatives to more traditional methods, especially concerning in situ environmental analysisThis work was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalization (POCI), and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-029547—PTDC/ASP-PES/29547/2017. This work received support by UIDB/50006/2020, UIDP/50006/ 2020 and LA/P/0008/2020 by the Fundação para a Ciência e a Tecnologia (FCT), Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds. T.M.B.F. Oliveira thanks the Brazilian agencies CNPq (Proc. 420261/2018-4 and 308108/2020-5) and FUNCAP (Proc. BP4-0172-00111.01.00/20) for their financial support, and he is grateful to UFCA and CAPES (Finance code 001) for supporting his investigations. F.W.P. Ribeiro thanks all support provided by the UFCA’s Pro-Rectory of Research and Innovation and the funding provided by FUNCAP-BPI (Proc. BP4-0172-00150.01.00/20) and CNPq (Proc. 406135/2018-5). P. de Lima-Neto thanks the financial support received from CNPq projects 408626/2018-6 and 304152/2018-8 and FUNCAP project FCT-00141-00011.01.00/18. A. N. Correia thanks the financial support received from CNPq projects: 305136/2018-6 and 405596/2018-9info:eu-repo/semantics/publishedVersio

    Rutin-functionalized multi-walled carbon nanotubes: molecular docking, physicochemistry and cytotoxicity in fibroblasts

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    Multi-Walled Carbon Nanotubes (MWCNT) have been functionalized with rutin through three steps (i. reaction step; ii. purification step; iii. drying step) and their physicochemical properties investigated with respect to morphological structure, thermal analysis, Fourier Transform Infrared Spectroscopy (FTIR), and cytotoxicity. The molecular docking suggested the rutin-functionalized MWCNT occurred by hydrogen bonds, which was confirmed by FTIR assays, corroborating the results obtained by thermal analyses. A tubular shape, arranged in a three-dimensional structure, could be observed. Mild cytotoxicity observed in 3T3 fibroblasts suggested a doseeffect relationship after exposure. These findings suggest the formation of aggregates of filamentous structures on the cells favoring the cell penetration.The authors acknowledge Classius Ferreira da Silva, from the Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, for the scanning electron microscopy analyses.info:eu-repo/semantics/publishedVersio

    The North African coastal low level wind jet: a high resolution view

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    The North African coastal low-level jet (NACLLJ) lies over the cold Canary current and is synoptically linked to the Azores Anticyclone and to the continental thermal low over the Sahara Desert. Although being one of the most persistent and horizontally extended coastal wind jets, this is the first high resolution modelling effort to investigate the NACLLJ climate. The current study uses a ROM atmospheric hindcast simulation with ~ 25 km resolution, for the period 1980–2014. Additionally, the underlying surface wind features are also scrutinized using the CORDEX-Africa runs. These runs allow the building of a multi-model ensemble for the coastal surface flow. The ROM and the CORDEX-Africa simulations are extensively evaluated showing a good ability to represent the surface winds. The NACLLJ shows a strong seasonal cycle, but, unlike most coastal wind jets, e.g. the California one, it is significantly present all year round, with frequencies of occurrence above 20%. In spring and autumn, the maxima frequencies are around 50%, and reach values above 60% in summer. The location of maximum frequency of occurrence migrates meridionally from season to season, being in winter and spring upwind of Cap-Vert, and in summer and autumn offshore the Western Sahara. Analogously, the lowest jet wind speeds occur in winter, when the median is below 15 m/s. In summer, the jet wind speed median values are ~ 20 m/s and the maxima are above 30 m/s. The jet occurs at heights ~ 360 m. A momentum balance is pursued disclosing that the regional flow is almost geostrophic, dominated by the pressure gradient and Coriolis force. Over the jet areas the ageostrophy is responsible for the jet acceleration

    Peces capturados en la campaña "CIGALA-79" a lo largo de la Plataforma Atlántica de la Península Ibérica (División IX-a del ICES)

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    En el presente trabajo se relacionan las especies de peces capturados en la Campaña "CIGALA -79 ", que tuvo lugar del 6 de agosto al 4 de setiembre de 1979 a lo largo de la División IX-a del ICES. Se expresa el número de ejemplares capturados de cada especie, por zona de latitud y estrato de profundidad. Se citan un total de 109 especies de peces.No presente traballo relacionam-se as especies de peixes capturados no Cruzeiro "CIGALA-79", que teve lugar de 6 de Agosto a 4 de Setembro de 1979 ao tongo da Dioistio IX-a do ICES. Expressa-se o número de exemplares capturados de cada espécie por zona de latitude e estrato de profuntlidade. Citam-se um total de 109 espécies de peixes.The following study relates the species of captured fishes in the survey "CIGALA- 79" that has been realized since the 6th August until the 4th September 1979 along the Division IX-a of ICES. It is reported the number of captured individuals of each species by area of latitude and stratum of depth, A total of 109 species of fishes are cited,Versión del editor
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