720 research outputs found

    Al2O3-3YTZP-Graphene multilayers produced by tape casting and spark plasma sintering

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    This work aims to establish a colloidal route to obtain laminates of alumina zirconia combining layers with and without graphene. Green tapes of alumina, alumina with 5 vol.% of 3Y-TZP and alumina with 5 vol.% of 3Y-TZP and graphene-oxide (2 vol.%) were obtained by aqueous tape casting. It is possible to design materials for different structural applications with a controlled microstructure with a high number of different layers. The tapes were punched into 20-mm discs, joined to form laminates alternating up to 18-layers, and sintered in one-step by spark plasma sintering (SPS) at 1400 degrees C. It has demonstrated that there is a significant graphite diffusion provoked by the required graphite holders into the SPS-furnace. Dense laminates with layer thicknesses similar to 100 mu m and good cohesion between layers were obtained. Nanoindentation results showed that hardness and elastic modulus values were higher than 27 GPa and 300 GPa, respectively, and similar for all layers. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.This work has been supported by Spanish Ministry of Economy and Competitiviness (MAT2012-31090). A. S. A. Chinelatto thanks to CAPES - Programa Ciencias sem Fronteiras (Brazil) for the concession of a fellowship for post-doctoral sabbatical grant in ICV-CSIC, Spain. A. Borrell, acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva contract (JCI-2011-10498) and the Generalitat Valenciana by the financial support for the BEST/2012/302 grant. Authors thank to Nanoinnova Technologies (Spain) for supplying the graphene oxide and helpful discussions.Rincón, A.; Moreno, R.; Chinelatto, ASA.; Gutierrez-Gonzalez, CF.; Rayón Encinas, E.; Salvador Moya, MD.; Borrell Tomás, MA. (2014). Al2O3-3YTZP-Graphene multilayers produced by tape casting and spark plasma sintering. Journal of the European Ceramic Society. 34(10):2427-2434. https://doi.org/10.1016/j.jeurceramsoc.2014.02.011S24272434341

    Gangrena de Fournier en paciente obeso con COVID-19: reporte de caso

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    La Gangrena de Fournier (GF) es una fascitis necrotizante que afecta los planos superficiales. Se presenta frecuentemente en hombres entre 50 y 79 años con una elevada tasa de mortalidad, la cual aumenta con la presencia de factores de riesgo destacándose entre ellos la diabetes y obesidad. Se reporta el caso de un paciente obeso diagnosticado con COVID-19 antes del ingreso y tratado con corticoides, que acude por aparente celulitis escrotal que evoluciona a GF, la cual fue diagnosticada 2 días luego de la hospitalización. Se le realiza intervención quirúrgica inmediata, previa cobertura antibiótica. La COVID-19 no tuvo relevancia clínica en la evolución y pronóstico de la GF; sin embargo, fueron las terapias desmesuradas las que influyeron negativamente. A pesar de ello, el paciente evolucionó favorablemente hasta su recuperación total. Palabras clave: Gangrena de Fournier, obesidad, COVID-19 (MeSH) DOI: http://dx.doi.org/10.17268/rmt.2020.v16i01.1

    An experimental model of episodic gas release through fracture of fluid confined within a pressurized elastic reservoir

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    We present new experiments that identify a mechanism for episodic release of gas from a pressurized, deformable reservoir confined by a clay seal, as a result of the transition from bulk deformation to channel growth through the clay. Air is injected into the center of a thin cylindrical cell initially filled with a mixture of bentonite clay and water. For sufficiently dry mixtures, the pressure initially increases with little volume change. On reaching the yield stress of the clay‐water mixture, the lid of the cell then deforms elastically and an air‐filled void forms in the center of the cell as the clay is driven radially outward. With continued supply of air, the pressure continues to increase until reaching the fracture strength of the clay. A fracture‐like channel then forms and migrates to the outer edge of the cell, enabling the air to escape. The pressure then falls, and the clay flows back toward the center of the cell and seals the channel so the cycle can repeat. The phenomena may be relevant at mud volcanoes

    The H-NS regulator plays a role in the stress induced by carbapenemase expression in acinetobacter baumannii

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    Disruption of the histone-like nucleoid structuring protein (H-NS) was shown to affect the ability of Gram-negative bacteria to regulate genes associated with virulence, persistence, stress response, quorum sensing, biosynthesis pathways, and cell adhesion. Here, we used the expression of metallo-β-lactamases (MBLs), known to elicit envelope stress by the accumulation of toxic precursors in the periplasm, to interrogate the role of H-NS in Acinetobacter baumannii, together with other stressors. Using a multidrug-resistant A. baumannii strain, we observed that H-NS plays a role in alleviating the stress triggered by MBL toxic precursors and counteracts the effect of DNA-damaging agents, supporting its role in stress response. IMPORTANCE Carbapenem-resistant A. baumannii (CRAB) is recognized as one of the most threatening Gram-negative bacilli. H-NS is known to play a role in controlling the transcription of a variety of different genes, including those associated with the stress response, persistence, and virulence. In the present work, we uncovered a link between the role of H-NS in the A. baumannii stress response and its relationship with the envelope stress response and resistance to DNA-damaging agents. Overall, we posit a new role of H-NS, showing that H-NS serves to endure envelope stress and could also be a mechanism that alleviates the stress induced by MBL expression in A. baumannii. This could be an evolutionary advantage to further resist the action of carbapenems.Fil: Huang, Fanny. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Fitchett, Noelle. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Razo Gutierrez, Chelsea. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Le, Casin. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Martinez, Jasmine. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Ra, Grace. California State University. College Of Natural Science And Mathematics; Estados UnidosFil: Lopez, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Gonzalez, Lisandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Sieira, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Vila, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Bonomo, Robert A.. Louis Stokes Cleveland Va Medical Center; Estados Unidos. Case Western Reserve University School of Medicine; Estados UnidosFil: Ramirez, Maria Soledad. California State University. College Of Natural Science And Mathematics; Estados Unido

    Efectos de la fibra dietética en la reducción de factores de riesgo cardiovasculares asociados a la obesidad

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    La obesidad es una pandemia que afecta a más de 650 millones de personas en todo el mundo. Los principales efectos del aumento y la acumulación de grasa corporal son la resistencia a la insulina, la dislipidemia y la hipertensión, los cuales son factores de riesgo para presentar enfermedades cardiovasculares. Por lo tanto, una de las terapias nutricionales para revertir estas alteraciones es el consumo de fibra dietética, que al evadir la digestión por enzimas humanas y la absorción intestinal, tienen efectos en todo el tracto digestivo disminuyendo la absorción de macronutrientes, aumentando la saciedad y modificando la microbiota intestinal. Por lo mencionado anteriormente, la presente revisión tiene como objetivo describir los efectos de la fibra dietética en la reducción de los factores de riesgo cardiovasculares asociados a la obesidad. Para el desarrollo de tal objetivo describiremos los factores de riesgo mencionados. Asimismo, describiremos la fibra dietética y los mecanismos implicados en la reducción de dichos factores. Palabras claves: Fibra dietética, enfermedades cardiovasculares y obesidad (DeCS). DOI: http://dx.doi.org/10.17268/rmt.2021.v16i02.0

    Human Subcutaneous Dirofilariasis, Russia

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    We report 14 cases of human subcutaneous dirofilariasis caused by Dirofilaria repens, diagnosed from February 2003 through July 2004, in patients from Rostov-on-Don, Russia. Serologic analysis showed evidence of high risk of exposure to D. repens. Surveillance studies on prevalence and prevention effectiveness of canine infection are needed to control this emerging zoonosis

    Otitis media and interna with or without polyps in cats:association between meningeal enhancement on postcontrast MRI, cerebrospinal fluid abnormalities, and clinician treatment choice and outcome

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    OBJECTIVES The aim of this study was to evaluate the association between meningeal enhancement (MgE) and cerebrospinal fluid (CSF) analysis results, their individual association with bacteriology results from affected ear samples and whether these test results influenced clinicians' therapeutic choice in cats with otitis media and interna (OMI). METHODS This was a multicentre retrospective study carried out over an 8-year period. Cats diagnosed with OMI, with or without a nasopharyngeal polyp, leading to peripheral vestibular signs were included. Only cats for which MRI with postcontrast T1-weighted sequences and CSF analyses available were included. Cats with intra-axial MRI lesions or empyema were excluded. RESULTS Fifty-eight cats met the inclusion criteria. MgE was reported in 26/58 cases, of which nine had an abnormal CSF result (increased total nucleated cell count [TNCC] or total protein); 32/58 cases had no MgE, of which 10 showed abnormal CSF results. There was no association between bacteriology results (external ear canal or bulla) and MgE or abnormal CSF results. CSF abnormalities were statistically significantly more common in acute cases (n = 16/37) than in chronic cases (n = 3/21; Fischer's test P = 0.04). Prednisolone was prescribed in 10/16 cases with increased TNCC. Among the 42 cases with normal TNCC, 15 received prednisolone and 13 received non-steroidal anti-inflammatory drugs. Various antimicrobial drugs were prescribed in 53/58 cats. Duration of antimicrobial treatment was similar, regardless of positive bacterial culture (5.58 vs 4.22 weeks), abnormal CSF (5.83 vs 4.76 weeks) or MgE (5.33 vs 4.90 weeks). CONCLUSIONS AND RELEVANCE No association was found between the CSF and MgE results. Furthermore, no association was found between MgE, CSF or bacteriology findings. In addition, abnormal CSF results might lead the clinician to treat with corticosteroids, but they did not have any impact on duration of antimicrobial treatment. CSF abnormalities were seen significantly less frequently in chronic cases. The outcome tended to be poorer when MgE was detected on MRI

    Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia

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    We present a comparison of our results from ground-based observations of asteroid (21) Lutetia with imaging data acquired during the flyby of the asteroid by the ESA Rosetta mission. This flyby provided a unique opportunity to evaluate and calibrate our method of determination of size, 3-D shape, and spin of an asteroid from ground-based observations. We present our 3-D shape-modeling technique KOALA which is based on multi-dataset inversion. We compare the results we obtained with KOALA, prior to the flyby, on asteroid (21) Lutetia with the high-spatial resolution images of the asteroid taken with the OSIRIS camera on-board the ESA Rosetta spacecraft, during its encounter with Lutetia. The spin axis determined with KOALA was found to be accurate to within two degrees, while the KOALA diameter determinations were within 2% of the Rosetta-derived values. The 3-D shape of the KOALA model is also confirmed by the spectacular visual agreement between both 3-D shape models (KOALA pre- and OSIRIS post-flyby). We found a typical deviation of only 2 km at local scales between the profiles from KOALA predictions and OSIRIS images, resulting in a volume uncertainty provided by KOALA better than 10%. Radiometric techniques for the interpretation of thermal infrared data also benefit greatly from the KOALA shape model: the absolute size and geometric albedo can be derived with high accuracy, and thermal properties, for example the thermal inertia, can be determined unambiguously. We consider this to be a validation of the KOALA method. Because space exploration will remain limited to only a few objects, KOALA stands as a powerful technique to study a much larger set of small bodies using Earth-based observations.Comment: 15 pages, 8 figures, 2 tables, accepted for publication in P&S
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