Determination and Finite Element Validation of the WYPIWYG Strain Energy of Superficial Fascia from Experimental Data

What-You-Prescribe-Is-What-You-Get (WYPIWYG) procedures are a novel and general phenomenological approach to modelling the behavior of soft materials, applicable to biological tissues in particular. For the hyperelastic case, these procedures solve numerically the nonlinear elastic material determination problem. In this paper we show that they can be applied to determine the stored energy density of superficial fascia. In contrast to the usual approach, in such determination no user-prescribed material parameters and no optimization algorithms are employed. The strain energy densities are computed solving the equilibrium equations of the set of experiments. For the case of superficial fascia it is shown that the mechanical behavior derived from such strain energies is capable of reproducing simultaneously the measured load-displacement curves of three experiments to a high accuracy

Optimization of a new Ni-free Ti alloy for applications in the implant field

Three new Ni-free Ti alloys, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr and Ti-16Hf-36.2Nb-1Zr (wt%), were designed and produced in order to obtain shape memory and/or low elastic modulus materials in order to avoid stress shielding and to enhance bone regeneration in the load transfer implant field. The alloys were microstructurally and mechanically characterized, cytotoxicity was evaluated using MG63 osteoblast-like cells. The elastic modulus of the new alloys (between 67-90 GPa) are smaller than those of the commercial alloys employed for implantation. The lowest elastic modulus alloy, Ti-16.2Hf-24.8Nb-1Zr (wt %), with 67.5 GPa, was optimized by cold work in order to determine the key factor that promotes the desired shape memory properties and/or low elastic modulus. A higher proportion of martensite was observed by optical and electron transmission microscopy in the low cold work samples compared to the quenched alloy. The elastic modulus for each cold work condition was evaluated by nanoindentation tests using a spherical tip. The elastic modulus decreases when increasing the cold work level. The lowest value corresponds to the 99% cold work condition, with 44 GPa, closer to that of cortical bone and smaller than the quenched alloy (67.5 GPa).Tres nuevas aleaciones de Ti libres de Ni, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr y Ti-16Hf-36.2Nb-1Zr, porcentajes en peso, fueron diseñadas y fabricadas con el fin de obtener memoria de forma y/o bajo módulo elástico con el objetivo de evitar el apantallamiento de cargas y mejorar la regeneración ósea en el campo de la implantología de transferencia de carga. Las aleaciones fueron caracterizadas microestructural y mecánicamente y la citotoxicidad fue evaluada utilizando osteoblastos MG63. El módulo elástico de las nuevas aleaciones (entre 67-90 GPa) es menor que el de las aleaciones comerciales utilizadas en implantología. El menor módulo elástico corresponde a la aleación Ti-16.2Hf-24.8Nb-1Zr, con 67.5 GPa y fue optimizado mediante trabajo en frío con el objetivo de determinar el factor responsable de la obtención de las propiedades deseadas de bajo módulo elástico y/o memoria de forma. Una mayor proporción de martensita fue observada por microscopía óptica y microscopía electrónica de transmisión en las muestras con bajo porcentaje de trabajo en frío en comparación con la muestra templada. El módulo elástico correspondiente a cada condición de trabajo en frío fue evaluado mediante nanoindentación con punta esférica. El módulo elástico disminuye al aumentar el porcentaje de trabajo en frío. El menor valor corresponde a la condición de 95% de trabajo en frío, con 44 GPa, valor cercano al del hueso cortical y menor que el del material templado (67.5 GPa).Peer Reviewe

Estudio de la biocompatibilidad de una nueva aleación beta-titanio de bajo módulo de elasticidad

Peer Reviewe

A multi-agent system with distributed bayesian reasoning for network fault diagnosis

In this paper, an innovative approach to perform distributed Bayesian inference using a multi-agent architecture is presented. The final goal is dealing with uncertainty in network diagnosis, but the solution can be of applied in other fields. The validation testbed has been a P2P streaming video service. An assessment of the work is presented, in order to show its advantages when it is compared with traditional manual processes and other previous systems

Chickenpox outbreak in Herrera del Duque, Badajoz, Spain.

Introducción. La varicela es una enfermedad de distribución mundial con una elevada morbilidad y pocas complicaciones, aunque puede presentar cuadros clínicos graves en inmunodeprimidos y adultos sanos. El objeto de este estudio es identificar y describir las características y los costes de un brote epidémico en Extremadura, cuya tasa anual de casos declarados al sistema de Enfermedades de Declaración Obligatoria (EDO) oscila en alrededor de 5 por 1.000 habitantes. Métodos.Estudio descriptivo con búsqueda activa de casos entre los meses de noviembre del año 2000 y marzo de 2001, y de la susceptibilidad de la cohorte escolarizada del colegio de Herrera del Duque (Badajoz). Las definiciones de casos fueron recogidas de los protocolos de la Red de Vigilancia de la comunidad extremeña. La confirmación microbiológica se realizó por aislamiento del virus y por presencia de marcadores IgM e IgG en el suero del enfermo. Se analizaron los costes tangibles directos e indirectos y los no tangibles del brote. Resultados.De los 75 casos identificados, 71 (94,7%) eran niños de entre uno y 9 años, predominando el sexo masculino. La tasa de ataque fue de 18,5 casos por 1.000 habitantes, y del 68,2% en convivientes menores de 10 años. La evolución fue benigna, sin ingresos hospitalarios ni complicaciones. Se encontró un 71,6% de niños susceptibles en los de entre 3 y 8 años. Se analizó una posible agregación temporal de casos en el colegio, obteniéndose un riesgo relativo (RR) de 5,01 (p < 0,001). Se aisló el virus en las 4 muestras de vesículas estudiadas y la serología (IgM) fue positiva en los 9 sueros estudiados. El coste total de brote fue de 927,21 e, con una media de 12,53 e por caso, y 205 días de pérdida escolar. Conclusión. Se confirmó la existencia de un brote de varicela en el colegio de la localidad de Herrera del Duque, con transmisión persona a persona, que afectó a niños de entre uno y 9 años. La elevada susceptibilidad del alumnado, las características de la docencia y las reuniones previas a los carnavales tuvieron un papel determinante en la propagación de la epidemia. El coste estimado para este brote se corresponde con un gasto un 76% menor del producido por la vacunación con una dosis de los 75 casos de este brote.S

Microplastic pollution in sublittoral coastal sediments of a North Atlantic island: The case of La Palma (Canary Islands, Spain)

In this work, the microplastic content of sediments collected in July 2020 between 5 and 7 m depth was studied in four locations of La Palma island (Canary Islands, Spain). At each sampling location, three samples were taken parallel to the shoreline. The microplastic content in each sampling corer was studied every 2.5 cm depth after digestion with a H2O2 solution followed by flotation in a saturated NaCl solution. Visualization of the final filtrates under a stereomicroscope revealed that all the sediment samples evaluated contained mostly microfibers (98.3%) which were mainly white/colorless (86.0%) and blue (9.8%), with an average length of 2423 ± 2235 (SD) mm and an average concentration of 2682 ± 827 items per kg of dry weight, being the total number of items found 1,019. Fourier Transform Infrared microscopy analysis of 13.9% (n = 139) of the microfibers also showed that they were mainly cellulosic (81.3%). No significant differences were found between the depths of the sediment. However, significant differences were found between the number of fibers from the sampling sites at the east and west of the island. Such variability could be driven by the winds and ocean mesoscale dynamics in the area. This study confirms the wide distribution of microfibers in sediments from an oceanic island like La Palma, providing their first report in marine sediments of the Canary Islands.En prensa3,20

Exploring Health Science Students’ Notions on Organ Donation and Transplantation: A Multicenter Study

The knowledge acquired during university education about organ donation and transplantation (ODT) decisively influences the information future health professionals transmit. This is important in ODT where the participation of the general public is essential to obtain organs. Objective: To determine notions of Spanish medicine and nursing students on ODT and its relationship with attitude toward ODT. Methods and Design: and design. We conducted a sociologic, multicenter, and observational study. The population for our study consisted of medical and nursing students in Spanish universities. Our database was the Collaborative International Donor Project, stratified by geographic area and academic course. A validated questionnaire (PCID-DTO-RIOS) was self-administered and completed anonymously. Our sample consisted of 9598 medical and 10, 566 nursing students (99% confidence interval; precision of ±1%), stratified by geographic area and year of study. Results: The completion rate for our study was 90%. Only 20% (n=3640) of students thought their notions on ODT were good; 41% (n=7531) thought their notions were normal; 36% (n=6550) thought their notions were scarce. Comparing groups, there were differences between those who believed that their notions on ODT were good (44% nursing vs 56% medical students; P < .000), and those who believed it scarce (54% nursing vs 46% medical students; P < .000). Notions on ODT were related with attitude toward the donation of one''s own organs: those who considered their notions were good were more in favor then those who considered it scarce (88% vs 72%; P < .000). Conclusion: Only 20% of Spanish medical and nursing students thought their notions on ODT were good. Having good knowledge is related to a favorable attitude towards ODT. Receiving specific information on the subject could improve their knowledge about ODT during their training

Conservative management of perforated duodenal diverticulum: a case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs

GWAS for Systemic Sclerosis Identifies Multiple Risk Loci and Highlights Fibrotic and Vasculopathy Pathways

Systemic sclerosis (SSc) is an autoimmune disease that shows one of the highest mortality rates among rheumatic diseases. We perform a large genome-wide association study (GWAS), and meta-analysis with previous GWASs, in 26,679 individuals and identify 27 independent genome-wide associated signals, including 13 new risk loci. The novel associations nearly double the number of genome-wide hits reported for SSc thus far. We define 95% credible sets of less than 5 likely causal variants in 12 loci. Additionally, we identify specific SSc subtype-associated signals. Functional analysis of high-priority variants shows the potential function of SSc signals, with the identification of 43 robust target genes through HiChIP. Our results point towards molecular pathways potentially involved in vasculopathy and fibrosis, two main hallmarks in SSc, and highlight the spectrum of critical cell types for the disease. This work supports a better understanding of the genetic basis of SSc and provides directions for future functional experiments.Funding: This work was supported by Spanish Ministry of Economy and Competitiveness (grant ref. SAF2015-66761-P), Consejeria de Innovacion, Ciencia y Tecnologia, Junta de Andalucía (P12-BIO-1395), Ministerio de Educación, Cultura y Deporte through the program FPU, Juan de la Cierva fellowship (FJCI-2015-24028), Red de Investigación en Inflamación y Enfermadades Reumaticas (RIER) from Instituto de Salud Carlos III (RD16/0012/0013), and Scleroderma Research Foundation and NIH P50-HG007735 (to H.Y.C.). H.Y.C. is an Investigator of the Howard Hughes Medical Institute. PopGen 2.0 is supported by a grant from the German Ministry for Education and Research (01EY1103). M.D.M and S.A. are supported by grant DoD W81XWH-18-1-0423 and DoD W81XWH-16-1-0296, respectively

Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties

Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale