Modelado y procesado láser de titanio para aplicaciones en ingeniería de superficies y desarrollo de aleaciones

Programa Oficial de Doutoramento en Enxeñaría Naval e Industrial . 5015V01[Resumen] Este trabajo pretende abordar el procesado láser de aleaciones de Ti. Por un lado, se ha estudiado la generación de recubrimientos mediante la técnica de láser cladding. El material de aporte utilizado generalmente en esta técnica es polvo con morfología esférica. En este trabajo se ha investigado la factibilidad de emplear polvo irregular más económico y se han comparado los resultados de los depósitos obtenidos para ambos tipos de polvo. Por otro lado se ha examinado la capacidad del sistema láser para producir aleaciones binarias de TiNb, bien como complemento de procesos pulvimetalúrgicos, empleando la técnica de refusión mediante láser o bien en técnicas de deposición láser a partir de la proyección y mezcla in-situ de polvos de Ti y Nb puros. Además se ha estudiado la posibilidad de efectuar oxidación de Ti mediante un láser continuo y se han buscado las estrategias y parámetros óptimos para obtener capas de óxido controladas. Finalmente, se han desarrollado modelos numéricos de los procesos anteriores y se han contrastado con los resultados experimentales.[Resumo] Este traballo pretende abordar o procesado láser de aliaxes de Ti. Por una banda, estudouse a xeración de recubrimentos mediante a técnica de láser cladding. O material de aporte utilizado xeralmente nesta técnica é po con morfoloxía esférica. Neste traballo investigouse a factibilidade de empregar po irregular máis económico e comparáronse os resultados dos depósitos obtidos para ambos tipos de po. Doutra banda examinouse a capacidade do sistema láser para producir aliaxes binarias de TiNb, ben como complemento de procesos pulvimetalúrxicos, empregando a técnica de refusión mediante láser ou ben en técnicas de deposición láser a partir da proxección e mestura in-situ de pos de Ti e Nb puros. Ademais estudouse a posibilidade de efectuar oxidación de Ti mediante un láser continuo e buscáronse as estratexias e parámetros óptimos para obter capas de óxido controladas. Finalmente, desenvolvéronse modelos numéricos dos procesos anteriores e contrastáronse cos resultados experimentais[Abstract] This work aims to address the laser processing of Ti alloys. On the one hand, the generation of coatings using the laser cladding technique has been studied. The feedstock material generally used in this technique is powder with spherical morphology. This work have investigated the feasibility of using a more economical irregular powder and the results of the coatings obtained for both types of powder have been compared. On the other hand the capacity of the laser system to produce binary TiNb alloys, either as a complement to powder metallurgical processes, using the laser refusion technique, or by means of laser deposition techniques, with projection and in-situ mixing of pure Ti and Nb powders has been analyzed. In addition, the possibility of oxidation of Ti by means of a continuous wave laser has been studied and the optimal strategies and parameters to obtain controlled oxide layers have been sought. Finally, numerical models of the above processes have been developed and contrasted with the experimental results

Autopercepción de la imagen corporal en mujeres y su correlación con el índice de masa corporal.

Objetivo: Determinar la correlación entre la autopercepción de la imagen corporal y el índice de masa corporal en mujeres. Material y Métodos: Se realizó un estudio transversal de correlación en mujeres adscritas a una unidad del primer nivel de atención en Cosoleacaque, Veracruz. El periodo del estudio comprendió de febrero a mayo de 2007. Incluyó a mujeres de 25 a 55 años que no presentaran algún tipo de discapacidad física y que no estuvieran embarazadas, con residencia en la región de un año o más. A cada mujer se le entrevistó e interrogó respecto a características sociodemográficas, antecedentes personales patológicos y actividad física. Después de la entrevista se realizaron mediciones antropométricas y una evaluación de la autopercepción de la imagen corporal con un instrumento diseñado ex profeso. Resultados: Se incluyó a 120 mujeres, con edad media fue de 37.6 ± 9.4 años. Sesenta y cuatro (53.3%) pertenecen al área rural y 52 (43.3%) tienen estudios de primaria. Con base en el IMC, 38.3% (46) de las mujeres presentó sobrepeso y 39.2% (47), obesidad. La correlación entre la autopercepción de imagen corporal y el IMC fue de 58%; esta correlación disminuyó según el grupo de peso: en mujeres con peso dentro de los intervalos normales fue 62% (0.30 a 0.82); en mujeres con sobrepeso, 28% (-0.01 a 0.53), y en mujeres con obesidad, 21% (-0.08 a 0.47). Conclusiones: La correlación entre la autopercepción y el IMC es menor que la informada en estudios previos, y lo es aún más en aquéllas con obesidad que en las de peso normal. En este estudio se observó que las mujeres con sobrepeso u obesidad se perciben como de peso normal

Tribo-mechanical and cellular behavior of superficially modified porous titanium samples using femtosecond laser

Abstract: In this work, the surface of porous titanium samples obtained by the space-holder technique was treated with a femtosecond laser to improve their osseointegration. Instrumented micro-indentation and scratch test were implemented to evaluate the tribo-mechanical behavior of the surface of the modified samples. A detailed study of micro-hardness, stiffness, scratch resistance and elastic recovery was performed. Also, in vitro analysis was carried out to evaluate the cellular behavior. Modified samples showed less ALP activity, which could indicate a greater differentiation of the cells. The cell culture was similar in all cases although more differentiated morphology, good cell adherence and biological response were observed on treated samples. Finally, the discs with a pore size between 100–200 μm present being potential candidates for the replacement of small portions of damaged cortical bone tissues.Ministerio de Ciencia e Innovación; PID2019-109371GB-I00 Junta de Andalucía; US-125977

Surface Modification of Porous Titanium Discs Using Femtosecond Laser Structuring

The failure of titanium implants is associated with two main problems that include the bone resorption and fracture of the surrounding bone tissue (stiffness incompatibility) and implant loosening (poor osseointegration). The development of porous titanium implants with low Young modulus solve the stress shielding phenomenon, while the modification of the implant surface must be implemented to promote a fast bond between the implant and bone. In this work, femtosecond laser micromachining was applied to modify the topography of the surface of Ti porous samples obtained by a space-holder technique to obtain hierarchical structures (micro and nano roughness patterns) to enhance osseointegration. Scanning electron microscopy, confocal laser microscopy, andimageanalysiswereusedforcharacterizationofthesurfacemorphology,roughness,andporosity before and after performing the laser treatment. Based on these results, the effect of the treatment on the mechanical behavior of the samples was estimated. In addition, a preliminary in-vitro test was performed to verify the adhesion of osteoblasts (filopodia presence) on modified titanium surface. Resultsrevealedthatlasertexturinggeneratedclustersofmicro-holesandmicro-columnsbothonthe flat surface of the samples and inside the macro-pores, and periodic nanometric structures across the entire surface. The porous substrate offers suitable biomechanics (stiffness and yield strength) and bio-functional behavior (bone ingrowth and osseointegration), which improves the clinic success of titanium implants.FEDER-Junta de Andalucía Research Project US-125977

Influence of Femtosecond Laser Modification on Biomechanical and Biofunctional Behavior of Porous Titanium Substrates

Bone resorption and inadequate osseointegration are considered the main problems of titanium implants. In this investigation, the texture and surface roughness of porous titanium samples obtained by the space holder technique were modified with a femtosecond Yb-doped fiber laser. Different percentages of porosity (30, 40, 50, and 60 vol.%) and particle range size (100–200 and 355–500 μm) were compared with fully-dense samples obtained by conventional powder metallurgy. After femtosecond laser treatment the formation of a rough surface with micro-columns and micro-holes occurred for all the studied substrates. The surface was covered by ripples over the micro-metric structures. This work evaluates both the influence of the macro-pores inherent to the spacer particles, as well as the micro-columns and the texture generated with the laser, on the wettability of the surface, the cell behavior (adhesion and proliferation of osteoblasts), micro-hardness (instrumented micro-indentation test, P–h curves) and scratch resistance. The titanium sample with 30 vol.% and a pore range size of 100–200 μm was the best candidate for the replacement of small damaged cortical bone tissues, based on its better biomechanical (stiffness and yield strength) and biofunctional balance (bone in-growth and in vitro osseointegration).Ministerio de Ciencia e Innovación del Gobierno de España PID2019-109371GB-100Junta de Andalucía (Spain) PAIDI P20-0067

Autophagy activation by resveratrol reduces severity of experimental rheumatoid arthritis

Instituto de Salud Carlos III; RETIC‐RIER RD16/0012/0002Instituto de Salud Carlos III; PI12/02771Instituto de Salud carlos III; AGRUP2015/05Instituto de Salud Carlos III; AGRUP2018/0

Neutrophils play a key role in the initiation of glomerular hematuria in a postinfectious igan experimental model

2 p.BACKGROUND AND AIMS: Hematuria is a common finding in patients with IgA nephropathy (IgAN), occurring mainly after upper respiratory tract infections.Hematuria can lead to acute kidney injury and chronic loss of renal function in IgAN.However, the mechanisms involved in egression of erythrocytes from the glomerular capillaries into the urinary space are unknown. To answer this question, we developed an infection with Streptococcus pneumoniae (SP) in a humanized experimental IgAN model (a1KICD89tg mice) that resembles the pathological and clinical findings of disease (IgA1 and soluble CD89 mesangial deposits, complement activation,proteinuria and hematuria).METHOD: a1KICD89tg mice (12 weeks old) received an intranasal instillation of SP(107 bacteria). Blood, urine and renal samples were obtained during 1 month after induction of respiratory infection. The presence of SP in lungs from these mice was confirmed by microbiological analysis. Hematuria was quantified in the urinary sediment and renal function was determined by biochemical analysis. Renal histological characteristics were evaluated by hematoxylin/eosin, masson’s trichrome and PAS staining. IgA glomerular deposits, activation of complement system and infiltration of proinflammatory cells was examined by immunohistochemistry or immunofluorescence. Circulating leukocyte populations were studied on a hemocytometer. Renal inflammatory cytokines, metalloproteases, as well as markers of tubular and glomerular damage were determined in kidneys by RT-PCR and western-blot. To further validate the role of neutrophils in this pathological setting, we selective depleted these cells through a single injection of anti-Ly6G mAb (200 mg/kg i.p).RESULTS: SP-intranasal instillation in a1KICD89tg mice increased hematuria,microalbuminuria and proteinuria, peaking at 48h after induction of the respiratory infection. SP instillation caused disruption of the glomerular basement membrane,with decreased expression of the slit diaphragm proteins nephrin and synaptopodin, as well as higher glomerular accumulation of IgA and proteins of complement system (C3, MBL). Hematuria intensity was positively correlated with the presence of interstitial F4/80þ macrophages, matrix metalloproteinase 9 (MMP-9), inflammatory cytokines and chemokines (IL-1b, IL-6, TNF-a, CCL-2, CCL5 and CX3CL1/CX3CR1) as well as p65 NF-jB activation. Hematuria was negatively correlated with anti inflammatory IL-10 mRNA expression, Factor H levels and collagen IV content. Notably, SP infection induced expression of the tubular injury markers N-GAL andKIM-1. Increased peripheral neutrophils levels were observed in the SP-infected a1KICD89tg mice. Mechanistically, anti-Ly6G-mediated neutrophil depletion reduced SP-mediated hematuria, proteinuria and albuminuria, prevented loss of synaptopodin and nephrin, decreased renal inflammation and MMP-9 expression in a1KICD89tg mice.CONCLUSION: In a humanized mouse model of IgAN, hematuria bouts following respiratory tract infections are caused by a neutrophil-mediated alteration of the glomerular filtration barrier (podocyte damage, complement deposits and loss of Collagen IV). These findings may help to unveil novel potential therapeutic approaches to combat one of the key elements in the progression of IgAN and related conditions.Peer reviewe

Implementación de la metodología flipped classroom en los laboratorios de Química Analítica

Adaptar el sistema tradicional de aprendizaje a las necesidades actuales del alumnado empleando la metodología flipped classroom en el laboratorio de Química Analítica I, con el objetivo de fomentar el aprendizaje utilizando herramientas digitales.Depto. de Química AnalíticaFac. de Ciencias QuímicasFALSEsubmitte

PhDAY 2020 -FOO (Facultad de Óptica y Optometría)

Por cuarto año consecutivo los doctorandos de la Facultad de Óptica y Optometría de la Universidad Complutense de Madrid cuentan con un congreso propio organizado por y para ellos, el 4º PhDAY- FOO. Se trata de un congreso gratuito abierto en la que estos jóvenes científicos podrán presentar sus investigaciones al resto de sus compañeros predoctorales y a toda la comunidad universitaria que quiera disfrutar de este evento. Apunta en tu agenda: el 15 de octubre de 2020. En esta ocasión será un Congreso On-line para evitar que la incertidumbre asociada a la pandemia Covid-19 pudiera condicionar su celebración

Homeopathic treatment for pediatric exogenous obesity in Pinar del Rio, Cuba

Introduction: overweight management should not be delayed until adulthood, as this would make it even harder to achieve lasting reductions in body weight. Objective: to evaluate the action of homeopathy to treat exogenous obesity. Material and Methods: a quasi-experimental intervention study was conducted in children aged 5- 18 years at Pepe Portilla Children Hospital of Pinar del Rio, Cuba, from January 2013 to November 2014. The sample was intentionally chosen: 98 obese children 5-18 years of age. Two groups were randomly selected: study and control groups. Group I was indicated to practice exercise, going on diet and homeopathic treatment when the symptoms were reported, and for Group II to practice exercises and going on diet. Their development was evaluated in ten sessions. A database was created with descriptive statistical processing and applying the Kolmogorov-Smirnov nonparametric hypothesis test (p = 0.00) to confirm the advantage of therapeutic method used. Results: female gender prevailed in both groups. There were no differences in the number of children regarding age groups. Breakdown of breastfeeding, low physical activity and high family per capita were risk factors for the development of exogenous obesity. In the study group, 44 patients showed good evolution, 4 patients as regular; while in the control group only 15 patients had an evolution described as good and 28 as regular. Only one of the patients in the study group showed poor outcomes. Conclusions: homeopathy is a useful therapeutic modality in the treatment of exogenous obesity