Exploiting the potential of bioreactors for creating spatial organization in the soil microbiome: A strategy for increasing sustainable agricultural practices

Industrial production of synthetic nitrogen fertilizers and their crop application have caused considerable environmental impacts. Some eco-friendly alternatives try to solve them but raise some restrictions. We tested a novel method to produce a nitrogen bioinoculant by enriching a soil microbial community in bioreactors supplying N2 by air pumping. The biomass enriched with diazotrophic bacteria was diluted and applied to N-depleted and sterilized soil of tomato plants. We estimated microbial composition and diversity by 16S rRNA metabarcoding from soil and bioreactors at different run times and during plant uprooting. Bioreactors promoted the N-fixing microbial community and revealed a hided diversity. One hundred twenty-four (124) operational taxonomic units (OTUs) were assigned to bacteria with a greater Shannon diversity during the reactor’s steady state. A total of 753 OTUs were found in the rhizospheres with higher biodiversity when the lowest concentration of bacteria was applied. The apparent bacterial abundance in the batch and continuous bioreactors suggested a more specific functional ecological organization. We demonstrate the usefulness of bioreactors to evidence hidden diversity in the soil when it passes through bioreactors. By obtaining the same growth of inoculated plants and the control with chemical synthesis fertilizers, we evidence the potential of the methodology that we have called directed bioprospecting to grow a complex nitrogen-fixing microbial community. The simplicity of the reactor’s operation makes its application promising for developing countries with low technological progress

Architectural optimization of an epoxy-based hybrid sol–gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

An epoxy-based hybrid sol–gel coating was prepared in various architectural configurations has beenstudied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layerof this coating presents defects consisting of macro-pores and protuberances, which opens access for cor-rosive species to reach the metallic substrate. These defects are suspected to result from the high reactivityof the substrate, as well as to the irregular topography of the substrate disrupted by the microstructureof the own magnesium alloy. Hence, a sol–gel coating in bilayer architecture is proposed, where the firstlayer would “inert” the surface of the magnesium substrate, and the second layer would cover the defectsof the first layer and also thickening the coating. The morphological characteristics of the sol–gel coatingswere analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated byOCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloridemedia. It is shown that both the architectural arrangement and the individual thickness of the first andsecond layers have an important influence on the anticorrosion performances of the protective system,just as much as its global thickness

Dry-sliding wear behavior of 3Y-TZP/Al2O3-NbC nanocomposites produced by conventional sintering and spark plasma sintering

[EN] This work presents the initial results of the dry-sliding wear behavior of 3 mol% yttria-stabilized zirconia reinforced with 5 vol% alumina-niobium carbide (3Y-TZP/5 vol% Al2O3-NbC) nanocomposites sintered by conventional sintering and spark plasma sintering methods in the temperature range of 1350-1450 degrees C. The reinforcement of 3Y-TZP matrix with hard nanoparticles aimed to improve wear strength of the composites. Wear tests were performed by the ball-on-disc method using alumina (Al2O3) and tungsten carbide with 6 wt% cobalt cermet (WC-6%Co) balls as counter-materials, a load of 15 N, a sliding distance of 2000 m, and a sliding speed of 0.1 m/s. Wear behavior was evaluated in terms of wear rate and FE-SEM micrograph analysis of the wear tracks. The nanocomposite sintered at 1450 degrees C by conventional sintering exhibited the least wear when tested with the WC-6%Co ball. Generally, the wear mechanism showed evidence of severe wear regime with both counter-materials.The authors acknowledge the Brazilian institutions CAPES-PVE (grant number 23038.009604/2013-12), FAPESP (grant number 2015/07319-8), Fundação Araucária (grant number 810/2014), European Union/Erasmus Mundus for doctorate mobility (grant number EB15DM1542), and the Spanish Ministry of Economy and Competitiveness (RYC-2016-20915).Salem, R.; Gutiérrez-González, C.; Borrell Tomás, MA.; Salvador Moya, MD.; Chinelatto, AL.; Chinelatto, AS.; Pallone, E. (2019). Dry-sliding wear behavior of 3Y-TZP/Al2O3-NbC nanocomposites produced by conventional sintering and spark plasma sintering. International Journal of Applied Ceramic Technology. 16(3):1265-1273. https://doi.org/10.1111/ijac.13151S12651273163Liu, H., Zhao, W., Ji, Y., Cui, J., Chu, Y., & Rao, P. (2017). Determination of fracture toughness of zirconia ceramics with different yttria concentrations by SEVNB method. 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Ceramics International, 43(5), 3931-3939. doi:10.1016/j.ceramint.2016.12.033Balko, J., Csanádi, T., Sedlák, R., Vojtko, M., KovalĿíková, A., Koval, K., … Naughton-Duszová, A. (2017). Nanoindentation and tribology of VC, NbC and ZrC refractory carbides. Journal of the European Ceramic Society, 37(14), 4371-4377. doi:10.1016/j.jeurceramsoc.2017.04.064Alecrim, L. R. R., Ferreira, J. A., Gutiérrez-González, C. F., Salvador, M. D., Borrell, A., & Pallone, E. M. J. A. (2017). Effect of reinforcement NbC phase on the mechanical properties of Al2O3-NbC nanocomposites obtained by spark plasma sintering. International Journal of Refractory Metals and Hard Materials, 64, 255-260. doi:10.1016/j.ijrmhm.2016.10.021Alecrim, L. R. R., Ferreira, J. A., Gutiérrez-González, C. F., Salvador, M. D., Borrell, A., & Pallone, E. M. J. A. (2017). Sliding wear behavior of Al2O3-NbC composites obtained by conventional and nonconventional techniques. Tribology International, 110, 216-221. doi:10.1016/j.triboint.2017.02.028Santos, C., Maeda, L. D., Cairo, C. A. A., & Acchar, W. (2008). Mechanical properties of hot-pressed ZrO2–NbC ceramic composites. International Journal of Refractory Metals and Hard Materials, 26(1), 14-18. doi:10.1016/j.ijrmhm.2007.01.008Ünal, N., Kern, F., Öveçoğlu, M. L., & Gadow, R. (2011). Influence of WC particles on the microstructural and mechanical properties of 3mol% Y2O3 stabilized ZrO2 matrix composites produced by hot pressing. Journal of the European Ceramic Society, 31(13), 2267-2275. doi:10.1016/j.jeurceramsoc.2011.05.032Sequeira, S., Fernandes, M. H., Neves, N., & Almeida, M. M. (2017). Development and characterization of zirconia–alumina composites for orthopedic implants. Ceramics International, 43(1), 693-703. doi:10.1016/j.ceramint.2016.09.216Schmitt-Radloff, U., Kern, F., & Gadow, R. (2017). Wire-electrical discharge machinable alumina zirconia niobium carbide composites – Influence of NbC content. Journal of the European Ceramic Society, 37(15), 4861-4867. doi:10.1016/j.jeurceramsoc.2017.07.014Akatsu, T., Nakanishi, S., Tanabe, Y., Wakai, F., & Yasuda, E. (2013). Toughening enhanced at elevated temperatures in an alumina/zirconia dual-phase matrix composite reinforced with silicon carbide whiskers. Journal of the European Ceramic Society, 33(15-16), 3157-3163. doi:10.1016/j.jeurceramsoc.2013.05.029Lee, D.-J., Choi, H.-S., Jin, F.-L., & Park, S.-J. (2015). A study on mechanical properties and microstructure of tetragonal zirconia-based composites. Journal of Industrial and Engineering Chemistry, 27, 322-328. doi:10.1016/j.jiec.2015.01.008Salem, R. E. P., Monteiro, F. R., Gutiérrez-González, C. F., Borrell, A., Salvador, M. D., Chinelatto, A. S. A., … Pallone, E. M. J. A. (2018). Effect of Al2O3-NbC nanopowder incorporation on the mechanical properties of 3Y-TZP/Al2O3-NbC nanocomposites obtained by conventional and spark plasma sintering. Ceramics International, 44(2), 2504-2509. doi:10.1016/j.ceramint.2017.10.235Schmitt-Radloff, U., Kern, F., & Gadow, R. (2018). Spark plasma sintering and hot pressing of ZTA-NbC materials – A comparison of mechanical and electrical properties. Journal of the European Ceramic Society, 38(11), 4003-4013. doi:10.1016/j.jeurceramsoc.2018.04.022Pędzich, Z., Haberko, K., Faryna, M., & Sztwiertnia, K. (2002). Interphase Boundary in Zirconia – Carbide Particulate Composites. Key Engineering Materials, 223, 221-226. doi:10.4028/www.scientific.net/kem.223.221Acchar, W., Zollfrank, C., & Greil, P. (2004). Microstructure and mechanical properties of WC-Co reinforced with NbC. Materials Research, 7(3), 445-450. doi:10.1590/s1516-14392004000300012Guillon, O., Gonzalez‐Julian, J., Dargatz, B., Kessel, T., Schierning, G., Räthel, J., & Herrmann, M. (2014). Field‐Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments. Advanced Engineering Materials, 16(7), 830-849. doi:10.1002/adem.201300409Munir, Z. A., Anselmi-Tamburini, U., & Ohyanagi, M. (2006). The effect of electric field and pressure on the synthesis and consolidation of materials: A review of the spark plasma sintering method. Journal of Materials Science, 41(3), 763-777. doi:10.1007/s10853-006-6555-2Lu, K. (2008). Sintering of nanoceramics. International Materials Reviews, 53(1), 21-38. doi:10.1179/174328008x254358Borrell, A., Fernández, A., Torrecillas, R., Córdoba, J. M., Avilés, M. A., & Gotor, F. J. (2010). Spark Plasma Sintering of Ultrafine TiCxN1−x Powders Synthesized by a Mechanically Induced Self-Sustaining Reaction. Journal of the American Ceramic Society, 93(8), 2252-2256. doi:10.1111/j.1551-2916.2010.03735.xBonache, V., Salvador, M. D., Fernández, A., & Borrell, A. (2011). Fabrication of full density near-nanostructured cemented carbides by combination of VC/Cr3C2 addition and consolidation by SPS and HIP technologies. International Journal of Refractory Metals and Hard Materials, 29(2), 202-208. doi:10.1016/j.ijrmhm.2010.10.007Gutiérrez-Mora, F., Cano-Crespo, R., Rincón, A., Moreno, R., & Domínguez-Rodríguez, A. (2017). Friction and wear behavior of alumina-based graphene and CNFs composites. Journal of the European Ceramic Society, 37(12), 3805-3812. doi:10.1016/j.jeurceramsoc.2017.02.024Wei, J., Lin, B., Wang, H., Sui, T., Yan, S., Zhao, F., … Fang, S. (2018). Friction and wear characteristics of carbon fiber reinforced silicon carbide ceramic matrix (Cf/SiC) composite and zirconia (ZrO2) ceramic under dry condition. Tribology International, 119, 45-54. doi:10.1016/j.triboint.2017.10.023Fan, H., Hu, T., Zhang, Y., Fang, Y., Song, J., & Hu, L. (2014). Tribological properties of micro-textured surfaces of ZTA ceramic nanocomposites under the combined effect of test conditions and environments. Tribology International, 78, 134-141. doi:10.1016/j.triboint.2014.05.010Gee, M., & Nunn, J. (2017). Real time measurement of wear and surface damage in the sliding wear of alumina. Wear, 376-377, 1866-1876. doi:10.1016/j.wear.2017.01.114Wang, Y., Yang, Y., Zhao, Y., Tian, W., Bian, H., & He, J. (2009). Sliding wear behaviors of in situ alumina/aluminum titanate ceramic composites. Wear, 266(11-12), 1051-1057. doi:10.1016/j.wear.2008.11.006Krell, A. (1996). Improved hardness and hierarchic influences on wear in submicron sintered alumina. Materials Science and Engineering: A, 209(1-2), 156-163. doi:10.1016/0921-5093(95)10155-1Botta F, W. ., Tomasi, R., Pallone, E. M. J. ., & Yavari, A. . (2001). Nanostructured composites obtained by reactive milling. Scripta Materialia, 44(8-9), 1735-1740. doi:10.1016/s1359-6462(01)00789-8Pallone, E. M. J. ., Trombini, V., Botta F, W. ., & Tomasi, R. (2003). Synthesis of Al2O3–NbC by reactive milling and production of nanocomposites. Journal of Materials Processing Technology, 143-144, 185-190. doi:10.1016/s0924-0136(03)00411-4ASTM G99‐03 Standard test method for wear testing with a pin‐on‐disc apparatus ASTM Annual Book of Standards vol.03. West Conshohocken PA;2003.Chen, W.-H., Lin, H.-T., Chen, J., Nayak, P. K., Lee, A. C., Lu, H.-H., & Huang, J.-L. (2016). Microstructure and wear behavior of spark plasma sintering sintered Al2O3/WC-based composite. International Journal of Refractory Metals and Hard Materials, 54, 279-283. doi:10.1016/j.ijrmhm.2015.07.030Espinosa-Fernández, L., Borrell, A., Salvador, M. D., & Gutierrez-Gonzalez, C. F. (2013). Sliding wear behavior of WC–Co–Cr3C2–VC composites fabricated by conventional and non-conventional techniques. Wear, 307(1-2), 60-67. doi:10.1016/j.wear.2013.08.003Bundschuh, W., & Gahr, K.-H. Z. (1991). Influence of porosity on friction and sliding wear of tetragonal zirconia polycrystal. Wear, 151(1), 175-191. doi:10.1016/0043-1648(91)90356-yBayer, R. J. (2004). Mechanical Wear Fundamentals and Testing, Revised and Expanded. doi:10.1201/9780203021798Zum Gahr, K.-H. (1989). Sliding wear of ceramic-ceramic, ceramic-steel and steel-steel pairs in lubricated and unlubricated contact. Wear, 133(1), 1-22. doi:10.1016/0043-1648(89)90109-9Kato, K., & Adachi, K. (2002). Wear of advanced ceramics. Wear, 253(11-12), 1097-1104. doi:10.1016/s0043-1648(02)00240-5Pasaribu, H. R., Sloetjes, J. W., & Schipper, D. J. (2004). The transition of mild to severe wear of ceramics. Wear, 256(6), 585-591. doi:10.1016/j.wear.2003.10.025Wang, S. W., Chen, L. D., Hirai, T., & Kang, Y. S. (1999). 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Chronic bovine besnoitiosis: histopathological findings and parasite distribution and load in subclinical cases [abstract]

PublishedPoster 50, Apicowplexa 201

Experiencias en la tutorización de enseñanzas técnicas

El PAT en la Escuela Politécnica está abierto a todos aquellos tutores que deseen formar parte del plan y también a todos los alumnos, que, voluntariamente pueden marcar la opción de participar en el plan en la matrícula, y también a aquellos que, a pesar de no marcar la opción en la matrícula, finalmente han decidido seguir el plan de acción tutorial. Esta característica de participación e inscripción voluntaria permite que el trabajo se realice más satisfactoriamente tanto por parte de tutores como por parte de los alumnos, puesto que han decidido seguir el plan por ello mismos y no como una imposición. Con este trabajo nos proponemos presentar nuestras experiencias en el desarrollo de la tutorización de nuestros estudiantes así como la evolución en el desarrollo de la tutorización por pares

The avoidance of G-CSF and the addition of prophylactic corticosteroids after autologous stem cell transplantation for multiple myeloma patients appeal for the at-home setting to reduce readmission for neutropenic fever

Background Autologous stem cell transplantation (ASCT) remains the standard of care for young multiple myeloma (MM) patients; indeed, at-home ASCT has been positioned as an appropriate therapeutic strategy. However, despite the use of prophylactic antibiotics, neutropenic fever (NF) and hospital readmissions continue to pose as the most important limitations in the outpatient setting. It is possible that the febrile episodes may have a non-infectious etiology, and engraftment syndrome could play a more significant role. The aim of this study was to analyze the impact of both G-CSF withdrawal and the addition of primary prophylaxis with corticosteroids after ASCT. Methods Between January 2002 and August 2018, 111 MM patients conditioned with melphalan were managed at-home beginning +1 day after ASCT. Three groups were established: Group A (n = 33) received standard G-CSF post-ASCT; group B (n = 32) avoided G-CSF post-ASCT; group C (n = 46) avoided G-CSF yet added corticosteroid prophylaxis post-ASCT. Results The incidence of NF among the groups was reduced (64%, 44%, and 24%; P2 (OR 6.1; P = 0.002) and G-CSF avoidance plus corticosteroids (OR 0.1; P60 years (OR 14.6; P = 0.04) and G-CSF avoidance plus corticosteroids (OR 0.07; P = 0.05). Conclusions G-CSF avoidance and corticosteroid prophylaxis post ASCT minimize the incidence of NF in MM patients undergoing at-home ASCT. This approach should be explored in a prospective randomized clinical trial

Coordinación del Plan de Acción Tutorial en la Escuela Politécnica Superior

Al igual que en cursos anteriores en la Escuela Politécnica se desarrolla, promovido por el Vicerrectorado de Estudios, Formación y Calidad, coordinado desde el Instituto de Ciencias de la Educación, el Plan de Acción Tutorial (PAT) el cual está abierto a todos aquellos tutores que deseen formar parte del plan y también a todos los estudiantes, que, voluntariamente pueden marcar la opción de participar en el plan en la matrícula, y también a aquellos que, a pesar de no marcar la opción en la matrícula, finalmente han decidido seguir el plan de acción tutorial. Esta característica de participación e inscripción voluntaria permite que el trabajo se realice más satisfactoriamente tanto por parte de tutores como por parte de los estudiantes, puesto que han decidido seguir el plan por ello mismos y no como una imposición. Con este resumen nos proponemos presentar nuestras experiencias en el desarrollo del PAT de nuestro centro