111 research outputs found

    Cell-Degradation of Calcium Phosphate Ceramics

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    Calcium phosphate ceramics are used in bone surgery under different forms: dense or porous ceramic s as bone substitute, thin ceramic coatings on metallic implants as an osseointegration enhancer. Their degradation depends on their physico-chemical properties and particularly on their chemical composition. Natural calcium phosphates of bone are degraded by mononuclear or multinuclear cells and the extracellular matrix induces the differentiation of the degrading-cells. Hydroxyapatite, which is one of the most used calcium phosphates , is known as a low degradation material. However, the histological analysis of implanted HA-materials both in animals and in humans showed that a cellular degradation took place on the surface of the material

    Designing multifunctional protective PVC electrospun fibers with tunable properties

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    In this work, the electrospinning technique is used for the fabrication of electrospun functional fibers with desired properties in order to show a superhydrophobic behavior. With the aim to obtain a coating with the best properties, a design of experiments (DoE) has been performed by controlling several inputs operating parameters, such as applied voltage, flow rate, and precursor polymeric concentration. In this work, the reference substrate to be coated is the aluminum alloy (60661T6), whereas the polymeric precursor is the polyvinyl chloride (PVC) which presents an intrinsic hydrophobic nature. Finally, in order to evaluate the coating morphology for the better performance, the following parameters-such as fiber diameter, surface roughness (Ra, Rq), optical properties, corrosion behavior, and wettability-have been deeply analyzed. To sum up, this is the first time that DoE has been used for the optimization of superhydrophobic or anticorrosive surfaces by using PVC precursor for the prediction of an adequate surface morphology as a function of the input operational parameters derived from electrospinning process with the aim to validate better performance.This research was funded by the Ministerio de Ciencia, Innovación y Universidades-Retos (Project RTI2018-096262-B-C41-MAITAI, Multidisciplinary Approach for the Implementation of new Technologies to prevent Accretion of Ice on aircraft), and by the Public University of Navarre (Project PJUPNA1929).This research was funded by the Ministerio de Ciencia, Innovaci?n y Universidades-Retos (Project RTI2018-096262-B-C41-MAITAI, Multidisciplinary Approach for the Implementation of new Technologies to prevent Accretion of Ice on aircraft), and by the Public University of Navarre (Project PJUPNA1929)

    Modeling experimental parameters for the fabrication of multifunctional surfaces composed of electrospun pcl/zno-nps nanofibers

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    In this work, a one-step electrospinning technique has been implemented for the design and development of functional surfaces with a desired morphology in terms of wettability and corrosion resistance by using polycaprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs). The surface morphology has been characterized by confocal microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA), whereas the corrosion resistance has been evaluated by Tafel polarization curves. Strict control over the input operational parameters (applied voltage, feeding rate, distance tip to collector), PCL solution concentration and amount of ZnO NPs have been analyzed in depth by showing their key role in the final surface properties. With this goal in mind, a design of experiment (DoE) has been performed in order to evaluate the optimal coating morphology in terms of fiber diameter, surface roughness (Ra), water contact angle (WCA) and corrosion rate. It has been demonstrated that the solution concentration has a significant effect on the resultant electrospun structure obtained on the collector with the formation of beaded fibers with a higher WCA value in comparison with uniform bead-free fibers (dry polymer deposition or fiber-merging aspect). In addition, the presence of ZnO NPs distributed within the electrospun fibers also plays a key role in corrosion resistance, although it also leads to a decrease in the WCA. Finally, this is the first time that an exhaustive analysis by using DoE has been evaluated for PCL/ZnO electrospun fibers with the aim to optimize the surface morphology with the better performance in terms of corrosion resistance and wettability.Project RTI2018-096262-B-C41–MAITAI, funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by ERDF 'A way of making Europe'. Grant PRE2019-090656, funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by ESF 'Investing in your future'. Project PJUPNA1929 funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by ERDF 'A way of making Europe' and by BEI

    Eine neue In-vivo-Technik zur dreidimensionalen Analyse der Translation der Femurkondylen und der Menisken unter dem Einfluß antagonistischer Muskelkräfte

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    The aim of our study was to develop a 3-D MR-based technique for the analysis of meniscal and femoral translations during flexion of the knee, and under the influence of antagonistic muscle forces in healthy subjects. In an open MR system, 5 knees were examined at 30 degrees and 90 degrees flexion using a T1-weighted 3-D gradient echo sequence. A force of 30 Newtons, first in the extending and then in the flexing direction, was applied to the distal lower leg. After three-dimensional reconstruction, the minimal distances between the centre of the tibial plateau and the posterior edge of the menisci and femoral condyles were determined. At 30 degrees flexion, the minimum distance for the meniscus was larger medially than laterally (23.2 +/- 1.8 mm vs. 16.2 +/- 3.3 mm), and this also applied to the condyles (25.1 +/- 1.5 vs. 19.0 +/- 3.0 mm). During flexion to 90 degrees, a posterior translation of 0.5 +/- 0.2 mm was observed for the lateral, and of 3.4 +/- 1.2 mm for the medial, meniscus. The condyles demonstrated a different posterior translation (lateral 2.2 +/- 0.56 mm; medial 1.8 +/- 1.9 mm). No obvious differences were found between extension and flexion muscle activity for the different positions of the knee. In the present study, a new 3-D technique is presented for the analysis of the femoral and meniscal translation at various positions of the knee, and under muscle activity. The results suggest different translation for the menisci and condyles

    Ultrasonic Monitoring of Recrystallization Textures in Aluminum

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    The present paper is an attempt to use ultrasonic velocity measurements to characterize the texture of an aluminum-magnesium alloy (Al 5xxx) and to compare the results with orientation imaging microscopy (OIM) results. The results are characterized in terms of three orientation distribution coefficients (ODC’s), W400, W420, and W440, each of which describes a particular forming anisotropy, and each of which has significant impact on the final products

    Ion exchanges in apatites. Effects on composition and properties

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    The modification of the composition of apatites materials can be made by several processes corresponding to ion exchange reactions which can conveniently be adapted to current coatings and ceramics and are an alternative to the set up of new synthesis methods. In addition to high temperature thermal treatments, which allow to virtually replace partly or totally monovalent OH- anion of stoichiometric hydroxyapatite by any halogen ion or carbonate, aqueous processes corresponding to dissolution-reprecipitation reactions have also been proposed and used. The most interesting possibilities are however provided by aqueous ion exchange reactions involving nanocrystalline apatites. These apatites are characterised by the existence on the crystal surface of a hydrated layer of loosely bound mineral ions which can be easily exchanged in solution. This layer offers a possibility to trap mineral ions and possibly active molecules which can modify the apatite properties. Such processes are involved in mineralised tissues and could be used in biomaterials for the release of active mineral species

    Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

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    Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves.Fil: Coughlan, Neil E.. The Queens University of Belfast; Irlanda. University College Cork; IrlandaFil: Cunningham, Eoghan M.. The Queens University of Belfast; IrlandaFil: Cuthbert, Ross N.. The Queens University of Belfast; Irlanda. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Joyce, Patrick W. S.. The Queens University of Belfast; IrlandaFil: Anastácio, Pedro. Universidade de Évora; PortugalFil: Banha, Filipe. Universidade de Évora; PortugalFil: Bonel, Nicolás. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Bradbeer, Stephanie J.. University of Leeds; Reino UnidoFil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Butitta, Vince L.. University of Wisconsin; Estados UnidosFil: Cadková, Zuzana. Czech University of Life Sciences; República ChecaFil: Dick, Jaimie T. A.. The Queens University of Belfast; IrlandaFil: Douda, Karel. Czech University of Life Sciences; República ChecaFil: Eagling, Lawrence E.. The Queens University of Belfast; IrlandaFil: Ferreira Rodríguez, Noé. Universidad de Vigo; EspañaFil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Johansson, Mattias L.. University of North Georgia; Estados UnidosFil: Kregting, Louise. The Queens University of Belfast; IrlandaFil: Labecka, Anna Maria. Jagiellonian University; PoloniaFil: Li, Deliang. Hunan Agricultural University; ChinaFil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Marescaux, Jonathan. University of Namur; Bélgica. e-biom; BélgicaFil: Morris, Todd J.. Fisheries and Ocean Canada; CanadáFil: Nowakowska, Patrycja. University of Gdansk; PoloniaFil: Ozgo, Malgorzata. Kazimierz Wielki University; PoloniaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Peribáñez, Miguel A.. Universidad de Zaragoza; EspañaFil: Riccardi, Nicoletta. Consiglio Nazionale delle Ricerche; ItaliaFil: Smith, Emily R. C.. University College London; Estados UnidosFil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin

    Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

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    Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves. © 2021 The Authors. Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Societ

    Immunomagnetic microbeads for screening with flow cytometry and identification with nano-liquid chromatography mass spectrometry of ochratoxins in wheat and cereal

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    Multi-analyte binding assays for rapid screening of food contaminants require mass spectrometric identification of compound(s) in suspect samples. An optimal combination is obtained when the same bioreagents are used in both methods; moreover, miniaturisation is important because of the high costs of bioreagents. A concept is demonstrated using superparamagnetic microbeads coated with monoclonal antibodies (Mabs) in a novel direct inhibition flow cytometric immunoassay (FCIA) plus immunoaffinity isolation prior to identification by nano-liquid chromatography–quadrupole time-of-flight-mass spectrometry (nano-LC-Q-ToF-MS). As a model system, the mycotoxin ochratoxin A (OTA) and cross-reacting mycotoxin analogues were analysed in wheat and cereal samples, after a simple extraction, using the FCIA with anti-OTA Mabs. The limit of detection for OTA was 0.15 ng/g, which is far below the lowest maximum level of 3 ng/g established by the European Union. In the immunomagnetic isolation method, a 350-times-higher amount of beads was used to trap ochratoxins from sample extracts. Following a wash step, bound ochratoxins were dissociated from the Mabs using a small volume of acidified acetonitrile/water (2/8 v/v) prior to separation plus identification with nano-LC-Q-ToF-MS. In screened suspect naturally contaminated samples, OTA and its non-chlorinated analogue ochratoxin B were successfully identified by full scan accurate mass spectrometry as a proof of concept for identification of unknown but cross-reacting emerging mycotoxins. Due to the miniaturisation and bioaffinity isolation, this concept might be applicable for the use of other and more expensive bioreagents such as transport proteins and receptors for screening and identification of known and unknown (or masked) emerging food contaminants
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