Determinant factors of long-term performance development in young swimmers

To develop a performance predictor model based on swimmers’ biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction. 91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors. Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] –2.05, P < .001), arm span (EST –0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST –0.17, P = .001) were entered in the final model. Over 3 consecutive seasons young swimmers’ performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.info:eu-repo/semantics/publishedVersio

Comparison between transfer path analysis methods on an electric vehicle

A comparison between transfer path analysis and operational path analysis methods using an electric vehicle is presented in this study. Structure-borne noise paths to the cabin from different engine and suspension points have been considered. To realise these methods, two types of test have been performed; operational tests on a rolling road and hammer tests in static conditions. The main aim of this work is assessing the critical paths which are transmitting the structure-borne vibrations from the electric vehicle's vibration sources to the driver's ear. This assessment includes the analysis of the noise contribution of each path depending on the frequency and vehicle speed range and moreover, the assessment of the path noise impact for harmonic orders which arise due to the physical components of the electric vehicle. Furthermore, the applicability of these methods to electric vehicles is assessed as these techniques have been extensively used for vehicles powered with internal combustion engines

Brote de legionelosis asociado a un balneario

The start of seasonal activity at a spa in Guipuzcoa coincided with the detection of an associated legionnaire outbreak in 1998. This led to the closure of the premises and to the carrying out of opportune environmental and epidemiological studies. The latter included case-control study. A case was defined as a person who, either during his stay or in a period of 10 days thereafter, developed pneumonia or a clinical sindrome compatible with that of Pontiac fever (EIC-9).The environmental study included spa and surrounds, and samples of the sanitary water systems and all water therapy elements.12.5% of the 278 people surveyed in the Basque Autonomous Community matched the case definition. 9 had pneumonia and 27 Pontiac fever. The epidemic curve began on May 7th, peaked on May 14th and 15th, and finalized on the 20th. The risk of illness adjusted according to age, sex and tobacco consumption was associated with the length of stay at the spa (RR=118.5, 95% C.I.: 18.7-750.2) and with swimming-pool use. Serogroup 1 L. pneumophila was detected in counts above 103 ufc/l at different points in the water therapy system and in the shower in the room of one patient. The pulsed field gel eletrophoresis analysis of one of the biological samples and environmental samples allowed genotypic confirmation. The establishment was reopened to the public after emergency treatment was carried out and confirm that after 15 days no L. pneumophila had been detected in the environmental samples.En 1998 el inicio de la temporada de actividad de un balneario en Gipuzkoa coincidió con la detección de un brote de legionelosis asociado al mismo, lo cual condujo al cierre de la instalación y al estudio epidemiológico -casos y controles- y ambiental oportunos. Se definió como caso toda persona que durante su estancia en el balneario o durante los 10 días siguientes presentará neumonía o un cuadro febril compatible con fiebre de Pontiac.El estudio ambiental incluyó la inspección del balneario y entorno y muestreos de los sistemas sanitarios de agua y de los elementos de hidroterapia.De las 287 personas encuestadas de la Comunidad Autónoma Vasca, el 12.5% cumplían con la definición de caso; 9 casos presentaron neumonía y 26 fiebre de Pontiac. La curva epidémica se inició el 7 de mayo, alcanzando un pico los días 14 y 15 de mayo y finalizando el día 20. El riesgo de enfermar ajustado por edad, sexo y consumo de tabaco se asoció con la duración de la estancia en el balneario (OR=118.5, 95% I.C: 18.7-750.2) y con el uso de una piscina (OR=10.5, 95% I.C: 1.3-82.6). Se detecto L. pneumophila serogrupo1 en recuentos superiores a 103 ufc/l en diversos puntos de la red de hidroterapia y en la ducha de la habitación de uno de los enfermos. El análisis por electroforesis en campos pulsados de una muestra biológica y muestras ambientales permitió la confirmación genotípica. El establecimiento se abrió al público tras realizar un tratamiento de choque y comprobar que transcurridos 15 días no se detectó L. pneumophila en las muestras ambientales

Differential analysis of genome-wide methylation and gene expression in mesenchymal stemcells of patients with fractures and osteoarthritis

Insufficient activity of the bone-forming osteoblasts leads to low bone mass and predisposes to fragility fractures. The functional capacity of human mesenchymal stem cells (hMSCs), the precursors of osteoblasts, may be compromised in elderly individuals, in relation with the epigenetic changes associated with aging. However, the role of hMSCs in the pathogenesis of osteoporosis is still unclear. Therefore, we aimed to characterize the genome-wide methylation and gene expression signatures and the differentiation capacity of hMSCs from patients with hip fractures. We obtained hMSCs from the femoral heads of women undergoing hip replacement due to hip fractures and controls with hip osteoarthritis. DNA methylation was explored with the Infinium 450K bead array. Transcriptome analysis was done by RNA sequencing. The genomic analyses revealed that most differentially methylated loci were situated in genomic regions with enhancer activity, distant from gene bodies and promoters. These regions were associated with differentially expressed genes enriched in pathways related to hMSC growth and osteoblast differentiation. hMSCs from patients with fractures showed enhanced proliferation and upregulation of the osteogenic drivers RUNX2/OSX. Also, they showed some signs of accelerated methylation aging. When cultured in osteogenic medium, hMSCs from patients with fractures showed an impaired differentiation capacity, with reduced alkaline phosphatase activity and poor accumulation of a mineralized matrix. Our results point to 2 areas of potential interest for discovering new therapeutic targets for low bone mass disorders and bone regeneration: the mechanisms stimulating MSCs proliferation after fracture and those impairing their terminal differentiation

Comparison between transfer path analysis methods on an electric vehicle

A comparison between transfer path analysis and operational path analysis methods using an electric vehicle is presented in this study. Structure-borne noise paths to the cabin from different engine and suspension points have been considered. To realise these methods, two types of test have been performed; operational tests on a rolling road and hammer tests in static conditions. The main aim of this work is assessing the critical paths which are transmitting the structure-borne vibrations from the electric vehicle?s vibration sources to the driver?s ear. This assessment includes the analysis of the noise contribution of each path depending on the frequency and vehicle speed range and moreover, the assessment of the path noise impact for harmonic orders which arise due to the physical components of the electric vehicle. Furthermore, the applicability of these methods to electric vehicles is assessed as these techniques have been extensively used for vehicles powered with internal combustion engines.The authors would like to acknowledge the COST ACTION TU1105 for supporting this research

Efficiency analysis of spur gears with a shifting profile

A model for the assessment of the energy efficiency of spur gears is presented in this study, which considers a shifting profile under different operating conditions (40–600 Nm and 1500–6000 rpm). Three factors affect the power losses resulting from friction forces in a lubricated spur gear pair, namely, the friction coefficient, sliding velocity and load sharing ratio. Friction forces were implemented using a Coulomb’s model with a constant friction coefficient which is the well-known Niemann formulation. Three different scenarios were developed to assess the effect of the shifting profile on the efficiency under different operating conditions. The first kept the exterior radii constant, the second maintained the theoretical contact ratio whilst in the third the exterior radii is defined by the shifting coefficient. The numerical results were compared with a traditional approach to assess the results.The authors would like to acknowledge Project DPI2013-44860 funded by the Spanish Ministry of Science and Technology and the COST ACTION TU 1105 for supporting this research

Influencia del oxígeno a alta concentración en cámara hiperbárica sobre el metabolismo óseo

RESUMEN: Objetivos: Conocer las acciones del oxígeno a alta concentración en cámara hiperbárica (CH) sobre la expresión de genes relacionados con el metabolismo óseo en líneas celulares osteoblasticas y hueso trabecular humano. Material y métodos: Se analizó la expresión diferencial de varios genes relacionados con el metabolismo óseo (SOST, RUNX2, MMP14, OPG, HIF‐1α y SIRT1) en dos líneas celulares osteoblasticas humanas (Saos y Super‐Saos) y en fragmentos de hueso trabecular humano sometidos a una, tres o cinco sesiones de CH (90 minutos, oxigeno 100%; 2,3 atmosferas). En cada experimento se utilizó un control que no recibió CH. Resultados: No encontramos diferencias significativas tras la CH en la expresión de los genes estudiados, ni en las células ni en hueso trabecular. Solo en la línea celular Super‐Saos la expresión de OPG tras 5 sesiones de CH descendió 6 veces con respecto a la del grupo control (2‐ΔCt de 72; p=0,01). Conclusiones: El oxígeno a alta concentración en cámara hiperbárica no parece tener influencia en la expresión de genes relacionados con el metabolismo óseo

Advanced model for the calculation of meshing forces in spur gear planetary transmissions

This paper presents a planar spur gear planetary transmission model, describing in great detail aspects such as the geometric definition of geometric overlaps and the contact forces calculation, thus facilitating the reproducibility of results by fellow researchers. The planetary model is based on a mesh model already used by the authors in the study of external gear ordinary transmissions. The model has been improved and extended to allow for the internal meshing simulation, taking into consideration three possible contact scenarios: involute–involute contact, and two types of involute-tip rounding arc contact. The 6 degrees of freedom system solved for a single couple of gears has been expanded to 6 + 3n degrees of freedom for a planetary transmission with n planets. Furthermore, the coupling of deformations through the gear bodies’ flexibility has been also implemented and assessed. A step-by-step integration of the planetary is presented, using two typical configurations, demonstrating the model capability for transmission simulation of a planetary with distinct pressure angles on each mesh. The model is also put to the test with the simulation of the transmission error of a real transmission system, including the effect of different levels of external torque. The model is assessed by means of quasi-static analyses, and the meshing stiffness values are compared with those provided by the literature.The authors would like to acknowledge Project DPI2013-44860 funded by the Spanish Ministry of Science and Technology

Analysis of SNP-SNP interactions and bone quantitative ultrasound parameter in early adulthood

Background: Osteoporosis individual susceptibility is determined by the interaction of multiple genetic variants and environmental factors. The aim of this study was to conduct SNP-SNP interaction analyses in candidate genes influencing heel quantitative ultrasound (QUS) parameter in early adulthood to identify novel insights into the mechanism of disease. Methods: The study population included 575 healthy subjects (mean age 20.41; SD 2.36). To assess bone mass QUS was performed to determine Broadband ultrasound attenuation (BUA, dB/MHz). A total of 32 SNPs mapping to loci that have been characterized as genetic markers for QUS and/or BMD parameters were selected as genetic markers in this study. The association of all possible SNP pairs with QUS was assessed by linear regression and a SNP-SNP interaction was defined as a significant departure from additive effects. Results: The pairwise SNP-SNP analysis showed multiple interactions. The interaction comprising SNPs rs9340799 and rs3736228 that map in the ESR1 and LRP5 genes respectively, revealed the lowest p value after adjusting for confounding factors (p-value = 0.001, β (95% CI) = 14.289 (5.548, 23.029). In addition, our model reported others such as TMEM135-WNT16 (p = 0.007, β(95%CI) = 9.101 (2.498, 15.704), ESR1-DKK1 (p = 0.012, β(95%CI) = 13.641 (2. 959, 24.322) or OPG-LRP5 (p = 0.012, β(95%CI) = 8.724 (1.936, 15.512). However, none of the detected interactions remain significant considering the Bonferroni significance threshold for multiple testing (p<0.0001). Conclusion: Our analysis of SNP-SNP interaction in candidate genes of QUS in Caucasian young adults reveal several interactions, especially between ESR1 and LRP5 genes, that did not reach statistical significance. Although our results do not support a relevant genetic contribution of SNP-SNP epistatic interactions to QUS in young adults, further studies in larger independent populations would be necessary to support these preliminary findings.This study was supported by a grant PI-0414-2014 from Consejería de Salud (Junta de Andalucía, Spain). Correa-Rodríguez M is a predoctoral fellow (FPU13/ 00143) from the Ministerio de Educación, Cultura y Deporte (Programa de Formación del Profesorado Universitario)