Implantes personalizados de polimetilmetacrilato (PMMA) para aplicaciones en craneoplastia

Los implantes a la medida para aplicaciones en craneoplastias tienen el objetivo de restaurar la protección del cerebro que el cráneo proporcionaba y mejorar el aspecto de la superficie después de sufrir un traumatismo o para corregir una malformación. Los principales inconvenientes del procedimiento de craneoplastia incluyen la individualización de la geometría y las propiedades mecánicas del implante para que sea funcional. El objetivo de nuestra investigación fue proponer una metodología integrada para el dise~no biomecánico y fabricación de implantes craneales y aplicarlo a un caso de estudio de un implante personalizado craneofacial para el hueso frontal hecho con polimetilmetacrilato (PMMA) que cumpla con la geometría adecuada y las propiedades mecánicas para su funcionalidad. La primera etapa del procedimiento fue obtener los datos médicos del paciente a través de tomografía axial computarizada (TAC) y luego se realizó un procesamiento de las imágenes para crear un modelo 3D de la región de interés por medio de un software de procesamiento de imágenes. Se desarrollo el diseño del implante utilizando un software CAD y, finalmente, se utilizó la tecnología de prototipado rápido para crear el molde del implante final. La metodología utilizada nos permitió obtener un implante de acuerdo a los requerimientos geométricos y mecánicos. Del mismo modo, se observó que los costos finales de desarrollo del implante individualizado son competitivos, y permite que haya una reducción significativa del tiempo quirúrgico. Igualmente se realizó un análisis biomecánico por medio del método de los elemento finitos como validación del implante con las propiedades del PMMA. Por medio de este se pudo concluir que el PMMA proporciona las condiciones mecánicas suficientes para la protección de las estructuras cerebrales.Abstract. Custom implants for cranioplasty applications have the aim to restore the brain protection that the skull provided and improve the surface appearance after suffring a trauma or to correct a malformation. Major drawbacks of the procedure of cranioplasty include the individualization of the geometry and mechanical properties of the implant to make it functional. The aim of our investigation was to propose an integrated methodology to biomechanical design and manufacturing of cranial implants and apply it to a case study of a craniofacial custom implant for the frontal bone made with Polymethylmethacrylate (PMMA) that meets the suitable geometry and mechanical properties for its functionality. The first process step was to obtain the medical data from the patient through computed tomography; then the images were processed to create a 3D model of the interest region by an imaging processing software; we designed the implant using CAD software and finally we used rapid prototyping technology to create the implant mold to produce the final geometry of the implant. The used methodology allowed us to obtain an implant according to the geometric and mechanical requirements. Likewise, it was observed that the final costs of developing individualized implant are competitive with surgical time savings and further there is an increased quality of the procedure. Similarly a biomechanical analysis was performed using the finite element method as a validation of the implant with the properties of PMMA. Through this it was possible to concluded that the PMMA provides sufficient mechanical conditions for the protection of brain structures.Maestrí

Preconditioning of Bioactive Glasses before Introduction to Static Cell Culture: What Is Really Necessary?

Due to their high bioreactivity, the in-vitro analysis of bioactive glasses (BGs) can be challenging when it comes to maintaining a physiological pH. To improve BG biocompatibility, a heterogenic spectrum of preconditioning approaches, such as “passivation” of the BGs by incubation in cell culture medium, are used but have never been directly compared. In this study, the effect of passivation periods of up to 72 h on pH alkalization and viability of human bone marrow-derived mesenchymal stromal cells was evaluated to determine a time-efficient passivation protocol using granules based on the 45S5-BG composition (in wt%: 45.0 SiO2, 24.5 Na2O, 24.5 CaO, 6.0 P2O5) in different concentrations. pH alkalization was most reduced after passivation of 24 h. Cell viability continuously improved with increasing passivation time being significantly higher after passivation of at least 24 h compared to non-passivated 45S5-BG and the necessary passivation time increased with increasing BG concentrations. In this setting, a passivation period of 24 h presented as an effective approach to provide a biocompatible cell culture setting. In conclusion, before introduction of BGs in cell culture, different passivation periods should be evaluated in order to meet the respective experimental settings, e.g., by following the experimental protocols used in this study

PLASTIMONIUM, plastilina como una manera divertida para apropiación del patrimonio. Exposiciones de resultados.

This is a short article that summarizes some of the experiences of the social projection project “Plastimonium, Plastilina as a didactic strategy for the dissemination of heritage”, a dissemination strategy of the research project “Tunjan heritage locator.” Plastimonium is a project initially aimed at children with the aim of disseminating Tunja’s architectural heritage, proposing a didactic strategy for raising awareness and recognition of the value of the City’s Heritage of Cultural Interest. An exploratory research was carried out, with a structure that could be made more flexible after the confinement and different points of view were taken into account according to the partial results. A primary research method was used as part of the qualitative methodology based on direct observation of children’s attitudes during the workshops and results measured from surveys and interviews. The practice was developed with an active and participatory methodology. The results have been satisfactory in children and young people and the experiences have continued to be replicated even after the end of the initial project activities.El presente es un artículo corto que resume algunas de las experiencias del proyecto de proyección social “Plastimonium, Plastilina como estrategia didáctica para la difusión del patrimonio”, estrategia de difusión del proyecto de investigación “dLocalizador patrimonial tunjano”. Plastimonium es un proyecto inicialmente dirigido a niños con el objetivo de difundir el patrimonio arquitectónico de Tunja, planteando una estrategia didáctica para la sensibilización y reconocimiento del valor de los Bienes de Interés Cultural de la ciudad. Se realizó una investigación de tipo exploratorio, con una estructura que pudo flexibilizarse a raíz del confinamiento y se tuvieron presentes distintos puntos de vista de acuerdo con los resultados parciales. Se utilizó un método de investigación primario como parte de la metodología cualitativa a partir de la observación directa de las actitudes de los niños durante los talleres y de los resultados medidos a partir de encuestas y entrevistas. La práctica se desarrolló con una metodología activa y participativa. Los resultados han sido satisfactorios en niños y jóvenes y las experiencias se han continuado replicando aún después de terminar las actividades iniciales del proyecto

Facile Preparative Access to Bioactive Silicon Oxycarbides with Tunable Porosity

In the present work, Ca-containing silicon oxycarbides (SiCaOC) with varying Ca content have been synthesized via sol-gel processing and thermal treatment in inert gas atmosphere (pyrolysis). It has been shown that the as-prepared SiCaOC materials with low Ca loadings (Ca/Si molar ratios = 0.05 or 0.12) were X-ray amorphous; their glassy network contains Q(3) sites, indicating the presence of Ca2+ at non-bridging-oxygen sites. SiCaOC with high Ca content (i.e., Ca/Si molar ratio = 0.50) exhibits the presence of crystalline calcium silicate (mainly pseudowollastonite). Furthermore, it has been shown that the incorporation of Ca into the SiOC glassy network has a significant effect on its porosity and specific surface area. Thus, the as-prepared Ca-free SiOC material is shown to be non-porous and having a specific surface area (SSA) of 22.5 m(2)/g; whereas SiCaOC with Ca/Si molar ratio of 0.05 exhibits mesoporosity and a SSA value of 123.4 m(2)/g. The further increase of Ca content leads to a decrease of the SSA and the generation of macroporosity in SiCaOC; thus, SiCaOC with Ca/Si molar ratio of 0.12 is macroporous and exhibits a SSA value of 39.5 m(2)/g. Bioactivity assessment in simulated body fluid (SBF) confirms the hydroxyapatite formation on all SiCaOC samples after seven days soaking, unlike the relatively inert ternary silicon oxycarbide reference. In particular, SiCaOC with a Ca/Si molar ratio of 0.05 shows an increased apatite forming ability compared to that of SiCaOC with Ca/Si molar ratio of 0.12; this difference is considered to be a direct consequence of the significantly higher SSA of the sample with the Ca/Si ratio of 0.05. The present work indicates two effects of Ca incorporation into the silicon oxycarbide glassy network on its bioactivity: Firstly, Ca2+ is shown to contribute to the slight depolymerization of the network, which clearly triggers the hydroxyapatite formation (compare the bioactive behavior of SiOC to that of SiCaOC with Ca/Si molar ratio 0.12 upon SBF exposure); secondly, the Ca2+ incorporation seems to strongly affect the porosity and SSA in the prepared SiCaOC materials. There is an optimum of Ca loading into the silicon oxycarbide glassy network (at a Ca/Si molar ration of 0.05), which provides mesoporosity and reaches maximum SSA, both highly beneficial for the bioactive behavior of the materials. An increase of the Ca loading leads, in addition to the crystallization of calcium silicates, to a coarsening of the pores (i.e., macroporosity) and a significant decrease of the SSA, both negatively affecting the bioactivity

Effect of Sr, Mg and Fe substitution on thephysico-chemical and biological properties ofSi Ca P multilayer scaffolds

tIn this work, a new combination of ceramic materials is proposed for bone tissue engi-neering applications. Multilayer scaffolds consisting of a core composed mainly of calciumpyrophosphate and external coatings of silica and calcium doped with Fe3+, Sr2+and Mg2+were prepared. To study the influence of the arrangement of dopant ions in the externalcoatings, two different scaffolds were developed: scaffolds 3J consisting of a single exter-nal coating with 9 mol% of Fe3+, Sr2+and Mg2+ions; and scaffolds 3S comprising threeexternal coatings, each containing 3 mol% of Fe3+, Sr2+and Mg2+ions. Scaffolds were physico-chemically characterized and evaluated for in vitro bioactivity and cellular response in thepresence of MG-63 cells. The results showed that the core scaffold displayed no in vitro bioac-tivity or good cellular response, but served as a support for the external coatings given itsmechanical resistance. The cell viability of scaffolds 3J and 3S increased more than 100%in relation to the core, and also improved cell proliferation and adhesion resulting in adense layer of cells that covered the scaffolds’ entire surface. The arrangement of ions inthe external coatings did not influence the cellular response, but determined the bioactivityrate

A new population of the hooded antpitta (Grallaricula cucullata: Grallaridae) for the Colombian Central Andes

We report a new population of the Hooded Anpitta (Grallariculla cucullata) in the Central Andes of Colombia, a threatened bird species inhabiting montane cloud forests in Colombian and Venezuelan Andes. We present capture-rate data, which suggest the occurrence of a resident with the highest population size reported for this bird species.Presentamos una nueva población del Tororoi Cabecirrufo (Grallariculla cucullata), una especie de ave amenazada de los bosques montanos nublados de los Andes de Colombia y Venezuela. Presentamos datos de tasas de captura que indican la presencia de una población residente con el tamaño poblacional más alto reportado para la especie

Facile Preparative Access to Bioactive Silicon Oxycarbides with Tunable Porosity

In the present work, Ca-containing silicon oxycarbides (SiCaOC) with varying Ca content have been synthesized via sol-gel processing and thermal treatment in inert gas atmosphere (pyrolysis). It has been shown that the as-prepared SiCaOC materials with low Ca loadings (Ca/Si molar ratios = 0.05 or 0.12) were X-ray amorphous; their glassy network contains Q³ sites, indicating the presence of Ca²⁺ at non-bridging-oxygen sites. SiCaOC with high Ca content (i.e., Ca/Si molar ratio = 0.50) exhibits the presence of crystalline calcium silicate (mainly pseudowollastonite). Furthermore, it has been shown that the incorporation of Ca into the SiOC glassy network has a significant effect on its porosity and specific surface area. Thus, the as-prepared Ca-free SiOC material is shown to be non-porous and having a specific surface area (SSA) of 22.5 m²/g; whereas SiCaOC with Ca/Si molar ratio of 0.05 exhibits mesoporosity and a SSA value of 123.4 m²/g. The further increase of Ca content leads to a decrease of the SSA and the generation of macroporosity in SiCaOC; thus, SiCaOC with Ca/Si molar ratio of 0.12 is macroporous and exhibits a SSA value of 39.5 m²/g. Bioactivity assessment in simulated body fluid (SBF) confirms the hydroxyapatite formation on all SiCaOC samples after seven days soaking, unlike the relatively inert ternary silicon oxycarbide reference. In particular, SiCaOC with a Ca/Si molar ratio of 0.05 shows an increased apatite forming ability compared to that of SiCaOC with Ca/Si molar ratio of 0.12; this difference is considered to be a direct consequence of the significantly higher SSA of the sample with the Ca/Si ratio of 0.05. The present work indicates two effects of Ca incorporation into the silicon oxycarbide glassy network on its bioactivity: Firstly, Ca²⁺ is shown to contribute to the slight depolymerization of the network, which clearly triggers the hydroxyapatite formation (compare the bioactive behavior of SiOC to that of SiCaOC with Ca/Si molar ratio 0.12 upon SBF exposure); secondly, the Ca²⁺ incorporation seems to strongly affect the porosity and SSA in the prepared SiCaOC materials. There is an optimum of Ca loading into the silicon oxycarbide glassy network (at a Ca/Si molar ration of 0.05), which provides mesoporosity and reaches maximum SSA, both highly beneficial for the bioactive behavior of the materials. An increase of the Ca loading leads, in addition to the crystallization of calcium silicates, to a coarsening of the pores (i.e., macroporosity) and a significant decrease of the SSA, both negatively affecting the bioactivity

Sol–Gel Synthesis and Characterization of YSZ Nanofillers for Dental Cements at Different Temperatures

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-26, pub-electronic 2021-10-29Publication status: PublishedFunder: The project is co-financed by Greece and the EuropeanUnion (European Social Fund-ESF) by the Operational Program Human Resources Development,Education and Lifelong Learning 2014–2020.; Grant(s): MIS5047876Background: Yttria-stabilized zirconia nanoparticles can be applied as fillers to improve the mechanical and antibacterial properties of luting cement. The aim of this study was to synthesize yttria-stabilized zirconia nanoparticles by the sol–gel method and to investigate their composition, structure, morphology and biological properties. Methods: Nanopowders of ZrO2 7 wt% Y2O3 (nY-ZrO) were synthesized by the sol–gel method and were sintered at three different temperatures: 800, 1000 and 1200 °C, and their composition, size and morphology were investigated. The biocompatibility was investigated with human gingival fibroblasts (hGFs), while reactive oxygen species (ROS) production was evaluated through fluorescence analysis. Results: All synthesized materials were composed of tetragonal zirconia, while nanopowders sintered at 800 °C and 1000 °C additionally contained 5 and 20 wt% of the cubic phase. By increasing the calcination temperature, the crystalline size of the nanoparticles increased from 12.1 nm for nY-ZrO800 to 47.2 nm for nY-ZrO1200. Nano-sized particles with good dispersion and low agglomeration were received. Cell culture studies with human gingival fibroblasts verified the nanopowders’ biocompatibility and their ROS scavenging activity. Conclusions: the obtained sol–gel derived nanopowders showed suitable properties to be potentially used as nanofillers for dental luting cement

Dilemas de la paz territorial en los tiempos del post-acuerdo: Experiencias territoriales en la región del eje cafetero

El presente libro, tejido a múltiples voces, perspectivas, abordajes teóricos y metodológicos, se inscribe en los proyectos editoriales de la región eje cafetero que se alejan de las lecturas dicotómicas o categóricas, por el contrario, transita los laberintos que se abren camino cuando una sociedad se traza la difícil tarea de construir una paz territorial en medio de los escenarios de la guerra. La memoria social, las voces de sobrevivientes, organizaciones sociales, medios de comunicación, posturas oficiales y cívicas, las apuestas pedagógicas por la paz, las lecturas territoriales del conflicto y las múltiples secuelas de las variadas violencias constituyen los horizontes temáticos de los 12 capítulos del presente libro, interpretando las complejas realidades presentes en el corazón de la región cafetera. Resultado de multiplicidad de voces, formaciones disciplinares y experiencias vitales, así como de la diversidad de organizaciones, entidades y universidades que acogieron el llamado del ¨Programa de Investigación en Transiciones, Violencias y Memoria¨ para construir una apuesta editorial recreada en los marcos de la sociología relacional, las cuales, a partir de perspectivas históricas, críticas y situadas, adelantaron análisis situados en la región cafetera en los tiempos del postacuerdo.Ruta Pacífica de las Mujeres ; Sistema Universitario del Eje Cafetero ; Universidad Católica de Manizales ; Universidad Católica de Pereira ; Vicerrectoría de Investigaciones, Innovación y Extensión Editorial Universidad Tecnológica de Pereira Pereira, Colombia.CONTENIDO Prólogo ....................................................................................................................6 Jefferson Jaramillo Marín Encrucijadas de una paz inacabada. A manera de introducción.....................12 Por: Luis Adolfo Martínez Herrera y Oscar Arango Gaviria PARTE I................................................................................................................20 Las tensiones de la memoria histórica y de los medios de comunicación en el contexto regional ..................................................................................................20 CAPÍTULO UNO.................................................................................................21 La memoria histórica en la región......................................................................22 Alberto Berón Ospina CAPÍTULO DOS .................................................................................................38 La mutación del periodismo en tiempos transicionales....................................39 Juan Antonio Ruiz Romero PARTE II..............................................................................................................73 Excombatientes, reintegrados y sobrevivientes del conflicto armado..............73 CAPÍTULO TRES...............................................................................................74 Una guerra silenciada: enunciaciones iniciales sobre los actores ...................75 y las dinámicas del conflicto armado en el Eje Cafetero ..................................75 Oscar Fernando Martínez Herrera y Miguel Gómez Bermeo CAPÍTULO CUATRO .....................................................................................106 Experiencia institucional de la Agencia para la Reincorporación y la Normalización en la atención de personas que se acogen a procesos de desarme, desmovilización, reintegración y reincorporación en el Eje Cafetero: 2003- 2020 .....................................................................................................................107 José Luis Medrano Benavides, Lina Marcela Duque Ossa, Oscar Fernando Sanmiguel CAPÍTULO CINCO..........................................................................................137 Entre víctimas y victimarios. Percepciones sociales de sobrevivientes del conflicto armado ................................................................................................................138 Luis Adolfo Martínez Herrera y Nicolás Muñoz Giraldo CAPÍTULO SEIS...............................................................................................173 Transición y reincorporación desde el Jimmy Tatamá: entre retórica y territorialidad.....................................................................................................174 Julio César Murillo García PARTE III...........................................................................................................197 Organizaciones sociales, historias y pedagogías regionales para la paz .......197 CAPÍTULO SIETE............................................................................................198 La Unión Patriótica: notas históricas sobre su acción política en el departamento de Risaralda, marzo 28 de 1984 - enero 6 de 1989 ..........................................199 Jahir Rodríguez Rodriguez CAPÍTULO OCHO ...........................................................................................250 Quinchía: memoria latente de un pueblo ultrajado. Reflexiones sobre la reparación simbólica..........................................................................................251 Gina M. Arias-Rodríguez y Érika V. Tobón-González CAPÍTULO NUEVE .........................................................................................279 La escuela de liderazgo para la paz: seis años al servicio dela educación para la paz ...................................................................................................................280 Oscar Arango Gaviria CAPÍTULO DIEZ..............................................................................................313 Una experiencia de formación para la paz ......................................................314 Claudia Mónica Londoño V. y Claudia Patricia Herrera G.. ........................314 PARTE IV...........................................................................................................338 Secuelas del conflicto armado y redefiniciones de las nociones de memoria y transiciones..........................................................................................................338 CAPÍTULO ONCE............................................................................................339 Comprensiones psicosociales sobre la desaparición forzada en Colombia...340 Mitzin Guadalupe Mata Mata y Mauricio Orozco Vallejo CAPÍTULO DOCE............................................................................................362 Narrativas, obsolescencias y hegemonías.........................................................363 Camilo Lozano River