Direct solution of differential equations using the Wavelet-Galerkin method

International audienceThe use of compactly supported wavelet functions has become increasingly popular in the development of numerical solutions for differential equations, especially for problems with local high gradient. Daubechies wavelets have been successfully used as base functions in several schemes like the Wavelet-Galerkin Method, due to their compact support, orthogonality, and multi-resolution properties. Another advantage of wavelet-based methods is the fact that the calculation of the inner products of wavelet basis functions and their derivatives can be made by solving a linear system of equations, thus avoiding the problem of approximating the integral by some numerical method. These inner products were defined as connection coefficients and they are employed in the calculation of stiffness, mass and geometry matrices. In this work, the Wavelet-Galerkin Method has been adapted for the direct solution of differential equations in a meshless formulation. This approach enables the use of a multiresolution analysis. Several examples based on differential equations for beams and plates were studied successfully

The Mexican Spanish version of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR)

The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) is a new parent/patient reported outcome measure that enables a thorough assessment of the disease status in children with juvenile idiopathic arthritis (JIA). We report the results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Mexican Spanish language. The reading comprehension of the questionnaire was tested in 10 JIA parents and patients. Each participating centre was asked to collect demographic, clinical data and the JAMAR in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents. The statistical validation phase explored descriptive statistics and the psychometric issues of the JAMAR: the 3 Likert assumptions, floor/ceiling effects, internal consistency, Cronbach\u2019s alpha, interscale correlations, test\u2013retest reliability, and construct validity (convergent and discriminant validity). A total of 100 JIA patients (16% systemic, 16% oligoarticular, 30% RF positive polyarthritis, 38% other categories) and 99 healthy children, were enrolled at the paediatric rheumatology department of the Hospital General de Mexico. The JAMAR components discriminated well healthy subjects from JIA patients. However, there was no significant difference between healthy subjects and their affected peers in school related problem variable. All JAMAR components revealed good psychometric performances. In conclusion, the Mexican Spanish version of the JAMAR is a valid tool for the assessment of children with JIA and is suitable for use both in routine clinical practice and clinical research

Heparan sulfate and chondroitin sulfate: general aspects of their participation during Plasmodium falciparum development

La malaria es considerada una de las enfermedades infecciosas de mayor importancia alrededor del mundo debido a la alta morbimortalidad que causa cada año en países tropicales. A pesar de los esfuerzos de investigación en malaria, muchos de los mecanismos que entrañan las interacciones hospedero-parásito aún no son claros, lo que constituye un gran obstáculo en el manejo y control de la malaria. Numerosos estudios se han llevado a cabo en los últimos años en busca de una mejor comprensión de los mecanismos fisiopatológicos, diseño de nuevas drogas, diseño de una vacuna y bloqueo de la transmisión. En todos estos temas de investigación, un elemento común son los glicanos como moléculas clave en el ciclo de vida de los parásitos de la malaria. El objetivo de esta revisión es mostrar como los glicanos se necesitan para el desarrollo y la transmisión de Plasmodium y como esta información resulta ser una valiosa herramienta en la investigación para combatir la malaria. Métodos: La presente revisión se basó principalmente en artículos originales publicados entre 1985 y 2015, obtenidos de las bases de datos PubMed y EmBase. La búsqueda fue hecha en inglés y se usaron las palabras clave: glicanos sulfatados, malaria, Anopheles y Plasmodium. Conclusión: Los glicoconjugados sulfatados están íntimamente vinculados al desarrollo, la transmisión y la supervivencia de Plasmodium, tanto en el hospedero intermediario como en el hospedero definitivo. Una mejor comprensión del rol de los glicoconjugados sulfatados en la infección malárica permitiría el desarrollo de nuevas alternativas terapéuticas, así como el diseño de estrategias para inhibir la transmisión.Malaria is one of the most important infectious diseases worldwide due to its high morbidity and mortality rates every year in tropical countries. Despite efforts in malaria research, several mechanisms underlying hostparasite interactions remain unclear, which is a big obstacle for the management and control of malaria. Recently, numerous studies have attempted to provide a better understanding of the physiopathological mechanisms to assist in the design of new drugs, vaccines and transmission blocking agents. These research topics have indicated that glycans are key molecules in the life cycle of the malarial parasites. The aim of this review is to highlight the relevance of glycans for the development and transmission of Plasmodium and to use that information as a valuable research tool to fight malaria. Because glycans play roles in parasite invasion and interactions with the mosquito host, both of which are part of “parasite development”, this review seeks to specify the role of glycans in parasite development. Methods: This review was mainly based on research articles published between 1985 and 2015 that were obtained from the PubMed and Embase databases. The keywords used in this search were sulfated glycans, malaria, Anopheles and Plasmodium. Conclusions: Sulfated glycoconjugates are intimately linked to the development, transmission and survival of Plasmodium in the intermediate and definitive hosts. A better understanding of the role of sulfated glycoconjugates in malaria infection would permit the development of new therapeutic strategies and the design of strategies to inhibit parasite transmissio

Influencia del caucho reciclado en las propiedades físicas – mecánicas en una mezcla asfáltica en caliente, Trujillo 2021

El presente trabajo de investigación tiene la finalidad de determinar la influencia del caucho reciclado en las propiedades físicas y mecánicas en una mezcla asfáltica en caliente. La investigación es tipo experimental donde la base de esta investigación es el ensayo Marshall que se realizó a una mezcla convencional y la otra con adición de caucho reciclado; primero obtuvimos el óptimo contenido de cemento asfáltico entre 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5% y 8.0%, encontrando una mejor estabilidad en un 6.0%, por lo que fue el óptimo contenido de asfalto que encontramos. A base del óptimo contenido asfáltico encontramos el porcentaje necesario de caucho para poder comparar las propiedades físicas y mecánicas. Los porcentajes de caucho utilizado fueron de 0.5%, 1.0% y 1.5%. Al analizar el 0.5% de caucho arrojó un porcentaje de vacíos 4.11%, flujo de 9.28 y una estabilidad de 9.84KN, luego al analizar el 1.00% de caucho arrojó un porcentaje de vacíos de 3.85%, flujo de 9.72 y una estabilidad de 10.87 KN y por último se analizó el 1.50% de caucho y arrojó un porcentaje de vacíos de 3.54%, flujo de 10.14 mm y una estabilidad de 9.3 KN. Se concluyó que el óptimo porcentaje de cemento asfáltico para esta investigación es de 6.0% con un porcentaje de caucho al 1.0%, se mejoró la estabilidad de la mezcla modificada con caucho en un 10% con respecto a la mezcla tradicional. Por último, se realizó la comparación de costos entre una mezcla convencional y una modificada con caucho, de esta comparación se determinó que una carpeta asfáltica con caucho reduce el costo en un 24% con respecto a una carpeta asfáltica convencional

Estudio mecánico sobre la resistencia de la pared de la aorta humana como predictor de riesgo de rotura de aneurisma

Definir el riesgo de rotura de un aneurisma, se considera un factor básico para elegir el momento adecuado de la intervención quirúrgica. Uno de los parámetros clásico utilizados es el diámetro del aneurisma (Ley de la Place). Sin embargo, otro factor mecánico como es el cociente entre la tensión máxima que soporta la pared (depende del diámetro de la aorta y de la morfología) y de la resistencia del material (pared de la aorta) es un elemento poco conocido. La razón estriba en comparar aortas “sanas” con “patológicas”. Este estudio lo hemos realizado en colaboración con el Departamento de Ciencias de Materiales de la Universidad Politécnica de Madri

Influencia de la edad y los aneurismas en la rotura de la pared aorta ascendente

Para mejorar los criterios de diagnóstico y prevención de las enfermedades cardiovasculares resulta fundamental conocer las propiedades mecánicas de la pared arterial. Este trabajo estudia el comportamiento mecánico y la rotura de la aorta torácica ascendente humana, tanto para individuos sanos como en pacientes aneurismáticos. Se estudia, asimismo, la influencia de la edad en las propiedades mecánicas. Se ha evaluado el comportamiento mecánico hasta rotura de la aorta torácica ascendente de 23 donantes sanos cuyas edades varían desde los 15 a los 65 años, y de 14 pacientes aneurismáticos, con edades entre 40 y 87 años. Se han realizado ensayos de tracción tanto en dirección longitudinal como circunferencial para evaluar la anisotropía de la pared arterial. Los resultados muestran que la influencia de la edad en las propiedades mecánicas de la pared arterial es significativa, tanto para los individuos sanos como para los enfermos. No se encuentran diferencias significativas entre el comportamiento en rotura de las sanas y las aneurismáticas cuando se comparan pacientes de las mismas edades. En cambio, la zona de trabajo fisiológico de las aortas enfermas se sitúa en la parte más rígida de su respuesta mecánica, perdiendo parte de su función amortiguadora de las ondas de presión generadas por el corazón

Comparison of computed tomography and dual-energy X-ray absorptiometry in the evaluation of body composition in patients with obesity

Body composition; Computed tomography; Morbid obesityComposición corporal; Tomografía computarizada; Obesidad mórbidaComposició corporal; Tomografia computaritzada; Obesitat mòrbidaObjective: a) To evaluate the accuracy of the pre-existing equations (based on cm2 provided by CT images), to estimate in kilograms (Kg) the body composition (BC) in patients with obesity (PwO), by comparison with Dual-energy X-ray absorptiometry (DXA). b) To evaluate the accuracy of a new approach (based on both cm2 and Hounsfield Unit parameters provided by CT images), using an automatic software and artificial intelligence to estimate the BC in PwO, by comparison with DXA. Methods: Single-centre cross-sectional study including consecutive PwO, matched by gender with subjects with normal BMI. All the subjects underwent BC assessment by Dual-energy X-ray absorptiometry (DXA) and skeletal-CT at L3 vertebrae. CT images were processed using FocusedON-BC software. Three different models were tested. Model 1 and 2, based on the already existing equations, estimate the BC in Kg based on the tissue area (cm2) in the CT images. Model 3, developed in this study, includes as additional variables, the tissue percentage and its average Hounsfield unit. Results: 70 subjects (46 PwO and 24 with normal BMI) were recruited. Significant correlations for BC were obtained between the three models and DXA. Model 3 showed the strongest correlation with DXA (r= 0.926, CI95% [0.835-0.968], p<0.001) as well as the best agreement based on Bland – Altman plots. Conclusion: This is the first study showing that the BC assessment based on skeletal CT images analyzed by automatic software coupled with artificial intelligence, is accurate in PwO, by comparison with DXA. Furthermore, we propose a new equation that estimates both the tissue quantity and quality, that showed higher accuracy compared with those currently used, both in PwO and subjects with normal BMI.This study was supported by grants from the Instituto de Salud Carlos III (Fondo de Investigación Sanitaria, PI20/01806). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Actividades educativas en el yacimiento de vertebrados miócenos de Somosaguas (Universidad Complutense, Pozuelo de Alarcón, Madrid)

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Additive Manufacturing of Fe-Mn-Si-Based Shape Memory Alloys: State of the Art, Challenges and Opportunities

Additive manufacturing (AM) constitutes the new paradigm in materials processing and its use on metals and alloys opens new unforeseen possibilities, but is facing several challenges regarding the design of the microstructure, which is particularly awkward in the case of functional materials, like shape memory alloys (SMA), as they require a robust microstructure to withstand the constraints appearing during their shape change. In the present work, the attention is focused on the AM of the important Fe-Mn-Si-based SMA family, which is attracting a great technological interest in many industrial sectors. Initially, an overview on the design concepts of this SMA family is offered, with special emphasis to the problems arising during AM. Then, such concepts are considered in order to experimentally develop the AM production of the Fe-20Mn-6Si-9Cr-5Ni (wt%) SMA through laser powder bed fusion (LPBF). The complete methodology is approached, from the gas atomization of powders to the LPBF production and the final thermal treatments to functionalize the SMA. The microstructure is characterized by scanning and transmission electron microscopy after each step of the processing route. The reversibility of the &epsilon; martensitic transformation and its evolution on cycling are studied by internal friction and electron microscopy. An outstanding 14% of fully reversible thermal transformation of &epsilon; martensite is obtained. The present results show that, in spite of the still remaining challenges, AM by LPBF offers a good approach to produce this family of Fe-Mn-Si-based SMA, opening new opportunities for its applications.This research was supported by the Industry Department of the Basque Government through the ELKARTEK-MINERVA (KK-2022/000082) project, and also from the GIU-021/24 from the University of the Basque Country UPV/EHU. This work made use of the electron microscopes installed at the General Service of Electron Microscopy of Materials, of the SGIKER—UPV/EHU, and the Zeiss at LORTEK technology center. Lucía Del-Río acknowledges the Pre-Doctoral grant (PRE_2022_1_0109) from the Education Department of the Basque Government

Comparison of computed tomography and dual-energy X-ray absorptiometry in the evaluation of body composition in patients with obesity

Objectivea) To evaluate the accuracy of the pre-existing equations (based on cm2 provided by CT images), to estimate in kilograms (Kg) the body composition (BC) in patients with obesity (PwO), by comparison with Dual-energy X-ray absorptiometry (DXA). b) To evaluate the accuracy of a new approach (based on both cm2 and Hounsfield Unit parameters provided by CT images), using an automatic software and artificial intelligence to estimate the BC in PwO, by comparison with DXA.MethodsSingle-centre cross-sectional study including consecutive PwO, matched by gender with subjects with normal BMI. All the subjects underwent BC assessment by Dual-energy X-ray absorptiometry (DXA) and skeletal-CT at L3 vertebrae. CT images were processed using FocusedON-BC software. Three different models were tested. Model 1 and 2, based on the already existing equations, estimate the BC in Kg based on the tissue area (cm2) in the CT images. Model 3, developed in this study, includes as additional variables, the tissue percentage and its average Hounsfield unit.Results70 subjects (46 PwO and 24 with normal BMI) were recruited. Significant correlations for BC were obtained between the three models and DXA. Model 3 showed the strongest correlation with DXA (r= 0.926, CI95% [0.835-0.968], p&lt;0.001) as well as the best agreement based on Bland – Altman plots.ConclusionThis is the first study showing that the BC assessment based on skeletal CT images analyzed by automatic software coupled with artificial intelligence, is accurate in PwO, by comparison with DXA. Furthermore, we propose a new equation that estimates both the tissue quantity and quality, that showed higher accuracy compared with those currently used, both in PwO and subjects with normal BMI