2,171 research outputs found

    Characterisation of PVD-TiN coated austempered ductile iron: Effects of nodule count and austempering temperature

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    In this work PVD-TiN coatings are deposited on ADI substrates austempered at 280 and 360°C, with nodule counts varying between 490 and 1 100 nod/mm2. The deposition is performed at 300°C by the arc ion plating technique. The effects of the substrates' microstructure on the characteristics of the coatings and the possible changes in ausferritic microstructure owing to the effects of the deposition process are evaluated. The existing phases, preferred orientation, film thickness, hardness, Young's modulus, surface topography and adhesion of each coated sample are determined. A metallographic characterisation of the ausferritic matrices and determination of the retained austenite content are performed before and after deposition. The results obtained indicate that PVD-TiN coatings feature a preferred orientation of (111) planes parallel to the surface and film thicknesses of about 2m m. Knoop hardness is influenced by the substrates characteristics, the values range from 1 700 to 2 100 HK0.015. Nanohardness values are close to 25 GPa, while Young's modulus shows some scattering (323 to 336 GPa). The surface topography is dependent on the microstructure of the substrates and the surface preparation method employed as well as on the deposition process used. The adhesion strength quality of the coatings, according to the Rockwell-C adhesion test, can be related to HF1-HF2 and is affected neither by the hardness differences between the different substrates nor by the nodule count variation. After the coating process, the microstructure of ADI substrates only suffers negligible changes and the amount of retained austenite decreases slightly.Fil: Colombo, Diego Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Echeverría, María D.. Universidad Nacional de Mar del Plata; ArgentinaFil: Moncada, Osvaldo Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Massone, Juan Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

    Asociación entre Trastornos Óseos Degenerativos y Acumulación de Líquido en los Recesos de la Articulación Temporomandibular

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    ResumenEl Objetivo del presente estudio fue determinar la asociación entre presencia de líquido intra-articular y alteraciones degenerativas en las ATM de pacientes adultos con diagnóstico clínico de Trastornos Temporomandibulares, por medio de diagnóstico imagenológico, antes de iniciar su tratamiento.Material y MétodoSe reclutaron 135 pacientes consecutivos (promedio de edad = 33,3 años) que clínicamente presentan disfunciones de las ATM y que fueron examinados por medio de Resonancia Magnética (RM) y Tomografía Computada (TC). Los criterios de exclusión fueron: pacientes menores de 16 años, pacientes mayores de 65 años, pacientes portadores de prótesis dentarias removibles, con enfermedades sistémicas como gota, Osteoartrosis sistémica, hiperlaxitud ligamentaria, malformaciones anatómicas, enfermedades quísticas, tumorales, historia de trauma o cirugía de las ATM. Todos los pacientes fueron examinados utilizando el resonador magnético [Phillips Intera 1,5 T, bobina Sense Flex S Dual] en las secuencias; sagital DP-T2-Spir, coronal DP y dinámico ECHO gradiente y también fueron examinados por medio de Tomografía Computada (TC), con cortes de volúmenes-axiales y volúmenes-coronales de 625um de espesor [BrightSpeed®ELITE, General Electric, Milwaukee, USA)] tanto a boca abierta como cerrada, bajo los siguientes parámetros: FOV: 16.0cms, Algoritmo Hueso, Filtro Edge A2 y Matriz 512x512 pxs]. Los estudios imagenológicos de las ATMs formaron los siguientes ocho grupos: Grupo A: Ausencia de líquido (L) en ATM Derecha con Alteración Degenerativa (AD); Grupo B: Presencia de Líquido en ATM Derecha con AD; Grupo C: Ausencia de Líquido en ATM Izquierda con AD; Grupo D: Presencia de L en ATM Izquierda con AD; Grupo E: Ausencia de AD y Ausencia de L en ATM Derecha; Grupo F: Ausencia de AD y Presencia de L en ATM Derecha; Grupo G: Ausencia de L en ATM Izquierda; Grupo H: Presencia de L y ausencia de AD en ATM Izquierda. Los datos fueron analizados estadísticamente con la prueba Chi2 (Systat v12.0).ResultadoGrupo A: n= 61; Grupo B: n= 64; Grupo C: n= 54; Grupo D: n= 53; Grupo E; n=12; Grupo F; n=13; Grupo G: n=8 y Grupo H: n=5.ConclusiónNo existe asociación entre la presencia de líquido intra-articular y Alteraciones Degenerativas de las superficies articulares en la ATM.AbstractThe Objective of the present study was to determine the association between articular space effusion and degenerative bone disease in adult TMJ with internal derangement, previous any treatment, by images diagnosis.Materials y MethodsWere recruited 135 consecutives patients (X=33.3 years) that presented TMJ dysfunction were examined using Magnetic Resonance (MRI) [Phillips Intera 1,5 T, Sense Flex S Dual Coil] in sequences; sagital DP-T2-Spir, coronal DP and dynamic ECHO gradient and using Computed Tomography (TC) by axial-volumes slices and coronal-volumes slices of 625um of width [BrightSpeed®ELITE, General Electric, Milwaukee, USA], with the patient in open mouth and closed mouth under the next parameters: FOV: 16.0cms, Bone Algorithm, Edge Filter A2 and Matrix 512x512 pxs. The exclusion criteria was: patients below 16 years and above 65 years of age, patients using removable dental prosthetics, patients that presented systemic disease such as Gout Disease, Osteoarthrosis and hipermobility, anatomic structural alterations, Quistic or Tumor disease and TMJ surgery. The TMJ images studies formed the following eight groups: Group A: Absence of effusion (L) in right TMJ with Degenerative Disease (AD); Group B: Presence of L in right TMJ with AD; Grupo C: Absence of L in left TMJ with AD; Group D: Presence of L in left TMJ with AD; Group E: Absence of AD and absence of L in right TMJ; Group F: Absence of AD and presence of L in right TMJ; Group G: Absence of L in left TMJ; Group H: Presence of L and absence of AD in left TMJ. Data were statistically analyzed by Chi2 (Systat v12.0).ResultsGroup A: n= 61; Group B: n= 64; Group C: n= 54; Group D: n= 53; Group E; n=12; Group F; n=13; Group G: n=8 y Group H: n=5.ConclusionNo association was found between Degenerative Bone Disease and Temporo mandibular Joint Articular Space Effusion in TMJ

    Human colon cancer cell lines show a diverse pattern of nitric oxide synthase gene expression and nitric oxide generation.

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    A panel of human colonic adenocarcinoma cell lines was examined both for expression of mRNAs of the nitric oxide synthase (NOS) gene family and for evidence of enzymic activity based on citrulline and nitrite (NO2-) formation. Reverse transcription-polymerase chain reaction (RT-PCR), revealed that all lines (SW480, SW620, DLD-1 and WiDr) expressed mRNA for the Ca(2+)-dependent endothelial (e)NOS, while SW480 cells also expressed the Ca(2+)-dependent neuronal (n)NOS. The mRNA for the Ca(2+)-independent inducible (i)NOS was expressed both by cytokine-stimulated and by unstimulated SW480, SW620 and DLD-1 cells, but none was seen at any time in the WiDr cells. There was, however, little correlation between mRNA expression and enzymic activity based on citrulline and NO2- formation. Thus none of the cell lines exhibited measurable Ca(2+)-dependent NOS activity, while Ca(2+)-independent NOS activity was seen in all but the WiDr cells. Furthermore, DLD-1 cells generated citrulline with resultant NO2- formation only after stimulation with lipopolysaccharide (LPS) and/or cytokines, while SW480 and SW620 did so constitutively. Thus RT-PCR studies indicate that tumour cells of similar epithelial origin display a diverse pattern of NOS gene family expression, and parallel biochemical studies clearly indicate that such expression does not always result in measurable enzymic activity leading to the generation of NO

    Calidad de frutos cítricos en Colombia.

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    Se efectuaron análisis para determinar el valor nutritivo y comercial de frutas cítricas en 3 zonas del país. El material se seleccionó de las colecciones existentes en los Centros Nacionales de Investigaciones Palmira (Valle del Cauca), Tulio Ospina (Antioquia) y haciendas cercanas a la ciudad de Cartagena (Bolivar). Se incluyeron los siguientes grupos cítricos: naranjas, mandarinas, grapefruits, limones, limas ácidas, pomelos, tangelos, cidras, kumquats, limequats, citranges y trifoliados. Se encontró, que por lo general, los frutos presentan mejor calidad interna a bajas altitudes y disminuye a medida que aumenta la altitud. Los cambios más notables que se presentan al aumentar la altitud son: aumento de la intensidad del color de la corteza y la pulpa, en el espesor de la corteza, en la acidez y en el ácido ascórbico y disminución en el porcentaje de jugo. Las naranjas de ombligo se adaptan mejor a altitudes superiores a 1000 m.s.n.m. Las variedades de naranjas normales se adaptan a distintas altitudes, sin embargo, son más indicadas para bajas altitudes. Los tangelos, grapefruits y líneas ácidas se recomiendan para bajas altitudes. Por último, las mandarinas tienen una mayor capacidad de adaptación a las diversas altitude

    Small is fast: astrocytic glucose and lactate metabolism at cellular resolution

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    Brain tissue is highly dynamic in terms of electrical activity and energy demand. Relevant energy metabolites have turnover times ranging from milliseconds to seconds and are rapidly exchanged between cells and within cells. Until recently these fast metabolic events were inaccessible, because standard isotopic techniques require use of populations of cells and/or involve integration times of tens of minutes. Thanks to fluorescent probes and recently available genetically-encoded optical nanosensors, this Technology Report shows how it is now possible to monitor the concentration of metabolites in real-time and in single cells. In combination with ad hoc inhibitor-stop protocols, these probes have revealed a key role for K(+) in the acute stimulation of astrocytic glycolysis by synaptic activity. They have also permitted detection of the Warburg effect in single cancer cells. Genetically-encoded nanosensors currently exist for glucose, lactate, NADH and ATP, and it is envisaged that other metabolite nanosensors will soon be available. These optical tools together with improved expression systems and in vivo imaging, herald an exciting era of single-cell metabolic analysis

    Injectable hybrid hydrogels physically crosslinked based on carrageenan and green graphene for tissue repair

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    Injectable and biocompatible novel hybrid hydrogels based on physically crosslinked natural biopolymers and green graphene for potential use in tissue engineering are reported. Kappa and iota carrageenan, locust bean gum and gelatin are used as biopolymeric matrix. The effect of green graphene content on the swelling behavior, mechanical properties and biocompatibility of the hybrid hydrogels is investigated. The hybrid hydrogels present a porous network with three-dimensionally interconnected microstructures, with lower pore size than that of the hydrogel without graphene. The addition of graphene into the biopolymeric network improves the stability and the mechanical properties of the hydrogels in phosphate buffer saline solution at 37 °C without noticeable change in the injectability. The mechanical properties of the hybrid hydrogels were enhanced by varying the dosage of graphene between 0.025 and 0.075 w/v%. In this range, the hybrid hydrogels preserve their integrity during mechanical test and recover the initial shape after removing the applied stress. Meanwhile, hybrid hydrogels with graphene content of up to 0.05 w/v% exhibit good biocompatibility for 3T3-L1 fibroblasts; the cells proliferate inside the gel structure and show higher spreading after 48 h. These injectable hybrid hydrogels with graphene have promising future as materials for tissue repair.The research leading to these results received funding from the Xunta de Galicia Government: program of consolidation and structuring competitive research units [grant number: ED431C 2019/17]. Y.F. is a ‘Sara Borrell’ researcher funded by Instituto de Salud Carlos III (ISCIII) and co-funded by Fondo Europeo de Desarrollo Regional (FEDER) [CD21/00042]. Thanks to Corfo 22CVID-206836, CIPA, ANID Regional, GORE BIO BIO, R17A10003, ACE210016, ACE210012. Funding for open access charge was provided by Universidade da Coruna/CISU
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