Numerical analysis and simulations in bone remodeling models

Conclusions In the course of this Ph.D. thesis we studied several bone remodeling models, trying to develop a complete study from the mathematical and physical points of view. In Chapter 2, the Cowin and Hegedus model was introduced. In this model, the bone is considered as an elastic material. A variational formulation was provided, obtaining an elliptic variational equation for the displacement ¯eld and an ordinary di®erential equation which describes the evolution of the bone density. Applying the ¯nite ele- ment method and an Euler scheme to approximate the spatial variable and the time derivatives, respectively, we obtained a fully discrete problem and we proved an error estimates result. Moreover, under additional regularity assumptions, we derived the linear convergence of the algorithm. Numerical simulations in one, two and three dimensions were presented to show the accuracy and the behavior of the approximations. In the second part of this chapter, we considered a similar problem assuming now that the bone may come into contact with a rigid or a deformable obstacle. In order to model these two contact conditions, we used the classical Signorini condition and the normal compliance contact law, respectively. The variational formulation was obtained for both problems and the convergence of the solution to the contact problem with a deformable obstacle, when the deformability coeficient tends to zero, to the solution of the Signorini's problem was established. We introduced fully discrete aproximations and we proved an error estimates result for both problems. Finally, under additional regularity assumptions, we obtained the linear convergence of the algorithm and some simulations were also presented. The third chapter dealt with the numerical analysis, including numerical simulations in one and two dimensions, of a bone remodeling model introduced byWeinans, Huiskes and Grootenboer in [66]. A numerical algorithm for the variational problem, based on the ¯nite element method to approximate the spatial variable and an Euler scheme to discretize the time derivatives, was proposed, an error estimate on its solutions was obtained and its linear convergence was established under suitable regularity assump- tions. The numerical simulations demonstrated the accuracy of the approximations and some properties related to the behavior of the solution. Finally, in the last chapter, we proposed a new bone remodeling model in which we considered the bone as an piezoelectric material. This property of the bone tissue was suggested in 1957. However, it was not normally used to understand bone remodeling and there are not many models that justify bone remodeling based on bone piezoelec- tricity. We continued the work developed in the previous chapter, using this model to characterize the evolution of the bone density and the mechanical properties of the bone. Then, we extended the classical electro-mechanical dependence adding a func- tion ®(½) = ½°, which regulates the coupling between the mechanical and electric ¯elds. This function guarantees that the electric ¯eld increases with the density of the bone. The variational formulation for this model was derived and a numerical algorithm was proposed, coupling the electric and displacement ¯elds. Finally, error estimates were proved and the linear convergence was established under adequate regularity condi- tions. Again, the numerical results shown the accuracy of the approximations as well as the behavior of the solution, giving also a numerical justi¯cation of the electro- mechanical bone remodeling model. All the algorithms proposed in this Ph.D. thesis were implemented using MATLAB code and a good number of examples were computed. First, the one-dimensional exam- ples were chosen in such a way as to show the numerical convergence of the algorithms and also their linear convergence. Then, two-or three-dimensional examples were per- formed in order to show the behavior of the models. The existence and uniqueness of weak solutions for the discrete problems were ob- tained applying classical results on linear variational equations or nonlinear variational inequalities (see [44]). However, we remark that the existence and uniqueness results of weak solutions for the continuous variational formulations are open problems. In the Cowin and Hegedus model, this result was obtained for a similar variational formula- tion in which stronger assumptions were made over the data. Recently, Fern¶andez and Kuttler dealt with the model proposed byWeinans, Huiskes and Grootenboer obtaining an existence and uniqueness result for a regularized problem

Polyhydroxyalkanoates production from methane emissions in Sphagnum mosses: Assessing the effect of temperature and phosphorus limitation

Producción CientíficaThe isolation of highly efficient methanotrophic communities is crucial for the optimization of methane bioconversion into products with a high market value such as polyhydroxyalkanoates (PHA). The research here presented aimed at enriching a methanotrophic consortium from two different inocula (Sphagnum peat moss (Sp) and Sphagnum and activated sludge (M)) able to accumulate PHA while efficiently oxidizing CH4. Moreover, the effect of the temperature and phosphorus limitation on the biodegradation rate of CH4 and the PHA accumulation potential was investigated. Higher CH4 degradation rates were obtained under P availability at increasing temperature (25, 30 and 37 °C). The biomass enriched from the mixed inoculum always exhibited a superior biodegradation performance regardless of the temperature (a maximum value of 84.3 ± 8.4 mg CH4 h−1 g biomass−1 was recorded at 37 °C). The results of the PHB production showed that phosphorus limitation is required to promote PHB accumulation, the highest PHB content being observed with the Sphagnum inoculum at 25 °C (13.6 ± 5.6%). The differential specialization of the microbial communities depending on the enrichment temperature supported the key role of this parameter on the results obtained. In all cases after the completion of the enrichment process and of the P limitation tests, Methylocystis, a type II methanotroph known for its ability to accumulate PHA, was the genus that became dominant (reaching percentages from 16 to 46% depending on the enrichment temperature). Thus, the results here obtained demonstrated for the first time the relevance of the temperature used for the enrichment of the methanotrophic bacteria to boost PHA production yields under P limiting condition, highlighting the importance of optimizing culture conditions to improve the cost-efficiency of bioprocesses based on using methane as the primary feedstock for the PHA industrial market.Ministerio de Economía, Industria y Competitividad - FEDER (Project CTM2015-73228-JIN)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. UIC 71 and CLU 2017-09

Characterization of Lactobacillus rhamnosus MP01 and Lactobacillus plantarum MP02 and Assessment of Their Potential for the Prevention of Gastrointestinal Infections in an Experimental Canine Model

The aim of the present study was to evaluate the probiotic potential of Lactobacillus rhamnosus MP01 and Lactobacillus plantarum MP02, two strains isolated from canine milk. These two isolates were characterized in vitro for their survival to conditions similar to those found in the canine gastrointestinal tract, production of antimicrobial compounds, adherence to intestinal mucin, degradation of mucin, and antibiotic sensitivity. Globally, both strains exhibited a high in vitro probiotic potential. Finally, their potential for the prevention of gastrointestinal infections was evaluated in an experimental canine model using 1-month-old puppies. A group of 12 German shepherd puppies, 6 males and 6 females, received L. rhamnosus MP01 daily for 2 months and a second group of 12 puppies, 6 males and 6 females, of the same breed received L. plantarum MP02 during the same period of time. The same experimental approach was carried with Yorkshire puppies. Additionally, the trial included 12 dogs of each breed in the placebo groups. The results demonstrated that administration of the strains resulted in a significant preventive effect of gastrointestinal infections in such populations

SISTEMA DE TAREAS, PARA EL DESARROLLO DE HABILIDADES COGNITIVAS

En la Formación de pregrado del futuro profesional de las Ciencias la Cultura Fisca y el Deporte, según el nuevo modelo pedagógico, exige una formación más independiente siendo el auto aprendizaje el centro de su proceso de formación con una dedicación sistemática al estudio, con independencia y creatividad y  con un elevado desarrollo de la capacidad de gestionar sus propios conocimiento. Esto está reflejado en la auto preparación del estudiante y un sistema de tareas orientado por el profesor. El trabajo propone una metodología de sistema de tareas facilitando la auto preparación del estudiante permitiéndole estudiar con independencia. La metodología se corresponde con las funciones específicas determinadas a los docentes y a los estudiantes y expresan de forma independiente las tareas a desarrollar.Palabras claves: Investigación-acción, auto preparación, estudio independiente, sistema de tareas, interdisciplinariedad. AbstractIn the undergraduate training of the future professional of the Sciences, the Fisca Culture and Sports, according to the new pedagogical model, requires a more independent training, self-learning being the center of its training process with a systematic dedication to study, independently and creativity and with a high development of the ability to manage their own knowledge. This is reflected in the self-preparation of the student and a system of tasks guided by the teacher. The work proposes a methodology of system of tasks facilitating the selfpreparation of the student allowing him to study independently. The methodology corresponds to the specific functions determined to the teachers and the students and they express independently the tasks to be developed.Keywords: Action research, selfpreparation, independent study, task system, interdisciplinarit

Abdominal adiposity increases lordosis and doubles the risk of low back pain

Vertebral disorders have significant health and economic impacts, and due to aging and current lifestyle habits, there is a trend toward their increase. Obesity and the alignment of vertebral curvatures can be associated with back pain. Objective: This study aims to analyze whether general and abdominal obesity are associated with cervical, dorsal, and lumbar vertebral pain as well as increased or decreased values of cervical, dorsal, and lumbar vertebral curvatures. Methodology: Body composition, degree of vertebral curvature, and the perception of cervical, dorsal, and lumbar pain were evaluated in a study population of 301 people (>18 years old). Linear and logistic regression analyses were performed to evaluate the influence of several variables of body composition on vertebral angles and cervical, dorsal, and lumbar pain. Results: Lumbar pain was the most prevalent (66.1%), mainly affecting women (70.9%). They were also shown to have greater lumbar angles (p < 0.001). The degrees of lumbar curvature increased, as did the BMI, waist circumference, and waist-to-height ratio. Cervical and dorsal curvatures were increased by all the variables of adiposity and abdominal adiposity. It was found that people with abdominal obesity carried twice the risk of lower back pain than those without abdominal obesity (OR = 2.172, p < 0.05). In addition, an increased lumbar angle was related to an increased risk of low back pain (OR = 1.031, p < 0.05). Cervical pain, on the other hand, was associated with the waist-height index (OR = 0.948, p <0.01). Conclusions: This study shows that increased lumbar curvature and abdominal obesity may be risk factors for lower back pain. In addition, it shows an association between the amount of body and abdominal fat in relation to the degree of curvature of the spine in the sagittal plane. Investigating the effect of obesity on vertebral morphology and musculoskeletal disorders makes it possible to prescribe interventions and therapeutic strategie

Assessment of the differences in the phenolic composition and color characteristics of new strawberry (Fragaria x ananassa Duch.) cultivars by HPLC–MS and Imaging Tristimulus Colorimetry

The phenolic composition (by HPLC-DAD-MS) and color characteristics (by Imaging Tristimulus Colorimetry) of four strawberry cultivars that have shown good climate adaptation to subtropical area (Nikte, Zamorana, Jacona and Pakal) have been assessed. 24 monomeric phenolics were identified, including 15 anthocyanins, 5 phenolic acids, 1 flavanol and 4 flavonols. Nikte and Zamorana showed the highest phenolic potential mainly due to their higher content of anthocyanins, while Pakal was richer in phenolic acids. Regarding color, Nikte and Zamorana were the more similar cultivars having the lowest values of lightness and hue. On the contrary, the color of Pakal was quite different from all the rest, due to the specific distribution between pelargonidin and cyanidin. The inclusion of both phenolic and colorimetric information in the Linear Discriminant Analysis allowed reaching very good discriminations among cultivar

A Systematic Two-Sample Mendelian Randomization Analysis Identifies Shared Genetic Origin of Endometriosis and Associated Phenotypes

Endometriosis, one of the most common gynecological disorders, is a complex disease characterized by the growth of endometrial-like tissue in extra-uterine locations and is a cause of pelvic pain and infertility. Evidence from observational studies indicate that endometriosis usually appears together with several other phenotypes. These include a list of autoimmune diseases, most of them more prevalent in women, anthropometric traits associated with leanness in the adulthood, as well as female reproductive traits, including altered hormone levels and those associated with a prolonged exposure to menstruation. However, the biological mechanisms underlying their co-morbidity remains unknown. To explore whether those phenotypes and endometriosis share a common genetic origin, we performed a systematic Two-Sample Mendelian Randomization (2SMR) analysis using public GWAS data. Our results suggest potential common genetic roots between endometriosis and female anthropometric and reproductive traits. Particularly, our data suggests that reduced weight and BMI might be mediating the genetic susceptibility to suffer endometriosis. Furthermore, data on female reproductive traits strongly suggest that genetic variants that predispose to a more frequent exposure to menstruation, through earlier age at menarche and shorter menstrual cycles, might also increase the risk to suffer from endometriosis

Relación entre los actores y niveles de confianza en centros de educación secundaria del cantón Guayaquil (Ecuador)

The public policy of Ecuador has placed the improvement of educational quality as one of the main objectives of government management. The climate-school constructs, organizational climate, work climate, and institutional climate, are used in different environments to accentuate the importance of the relationship established between a management environment factor and the quality of results in organizations. Through out this study, the objective has been to analyze the variations in the relationship among the actors, and the levels of trust between the actors of the school organizational climate, according to the socioeconomic level, the role played in the educational community, or the type of socio-educational center. The study follows a new approach of an experimental, descriptive-comparative investigation, using techniques such as the survey, the interview, and the discussion group, adjusting to the mixed methodology according to the objectives and sense of the research proposed. In consideration of the results, we will appreciate that the relationships between the actors and the confidence levels of the actors show mostly positive indicators based on the responses of the participants in the study. However, the percentage of negative perceptions (24.34%) is a factor to consider, since it might suggest that these perceptions underlie indicators of distrust that should be taken into account for any future interventions. In conclusion, the schools participating in this study have built a mostly positive school organizational climate, which generates favorable spaces for innovation and change processes.La política pública del Ecuador ha ubicado a la mejora de la calidad educativa como uno de los principales objetivos de la gestión gubernamental. Los constructos clima-escolar, clima organizacional, clima de trabajo y clima institucional son utilizados en diferentes entornos para acentuar la importancia de la relación que se establece entre un ambiente de gestión satisfactorio y la calidad de resultados en las organizaciones. A través del presente estudio se planteó como objetivo el análisis de las variaciones de la relación entre los actores y los niveles de confianza entre los actores del clima organizacional escolar de acuerdo con el nivel socioeconómico, el rol desempeñado en la comunidad educativa o el tipo de centros escolares. El estudio corresponde a una investigación de tipo no experimental, descriptiva-comparativa, mediante técnicas como la encuesta, la entrevista y el grupo de discusión, ajustándose a la metodología mixta de acuerdo a los objetivos y sentido de la investigación planteada. Como resultados apreciaremos que las relaciones entre los actores y los niveles de confianza de los actores muestras indicadores mayoritariamente positivos en función de las respuestas de los participantes en el estudio, sin embargo el porcentaje de percepciones negativas (24,34%) es un dato a tener en cuenta, puesto que podría sugerir que subyacen en esas percepciones indicadores de desconfianza que habría que tomar en cuenta para posibles intervenciones posteriores. En conclusión, los centros escolares participantes de este estudio han construido un clima organizacional escolar mayoritariamente positivo, lo cual genera espacios favorables a procesos de innovación y cambio.Universidad Pablo de Olavid

Venciendo la degradación climática del patrimonio pétreo mediante recubrimiento con nanomateriales basados en carbono

Resumen de la comunicación oral presentada en el XVII Simposio de Investigadores Jóvenes de la RSEQ, celebrado en la Universidad de Alcalá de Henares, 23-26 noviembre 2021.Cada año se notan más los efectos del cambio climático, que conllevan episodios de lluvia más agresivos y cambios térmicos más acusados. Estos cambios meteorológicos suponen un impacto muy grave, como el daño que pueden generar al patrimonio pétreo, altamente amenazado sobretodo en piedras blandas debido a su susceptibilidad a daños ocasionados por el agua. Las administraciones responsables de la protección del patrimonio tratan de paliar este desgaste con medidas que buscan proteger el bien de interés, pero bajo la máxima de que sean tratamientos que no alteren la apariencia física del mismo y que sean reversibles. Estos tratamientos que se realizan, si bien no son agresivos con el monumento, resultan muy costosos e ineficaces cuando, por causa de la escasez de recursos, no pueden realizarse con la frecuencia requerida (al menos una vez cada 5 años). Y esto conduce a que muchos monumentos esperando el tratamiento van abandonándose a su suerte. Nuestro equipo ya ha logrado encontrar y patentar una posible alternativa de protección basada en óxido de grafeno, de excelentes características: un recubrimiento transparente, más duradero, resistente e inocuo para la piedra. Además, se cumplen los requerimientos específicos de la protección monumental, que es no poner en riesgo el aspecto físico ni la estética del monumento. Además, mediante la actual financiación del MICINN se explorarán otros nanomateriales sostenibles y biodegradables. Esta prometedora idea supondrá que ni la economía, pues es barato y perdura su protección periodos superiores a los 10 años, ni el medio ambiente, pues buscamos recubrimientos que cumplan con los principios de sostenibilidad ambiental, fueran afectadas. Y además este proyecto combina estos trabajos y pruebas con el desarrollo de una herramienta digital SIG que permita evaluar y calcular el mejor tratamiento y su coste para distintos monumentos de un territorio, así como gestionar mejor los limitados recursos de las administraciones que custodian estos monumentos, indicando la fecha y localización de las aplicaciones y la prioridad de actuación bajo criterios objetivos.Overcoming the climatic degradation of the stone-based cultural heritage by shielding with sustainable nanomaterials (NANOSHIELD). Proyecto MICINN Retos PID2020-120439RA-I00