Análisis de la validez de las ecuaciones de estimación del 1RM con técnica de parada: una nueva propuesta

This study validates new regression equations to estimate the value of the absolute maximum dynamic strength (1RM) by means of a maximum number of repetitions test to muscular failure (nRM) executed with stop technique. Also, this study assesses the validity of the equations that are already stablished in the international publications to estimate the load (% 1RM) and the 1RM value from a nRM test in executions with stop technique. The results indicate that the new equations proposed in this research [Bench Press 1RM = weight lifted in kg (-0,01841*nRM)+0,981; Full Squat 1RM = weight lifted in kg (-0,01176*nRM)+0,975] show substantially better validity levels (SEM = 1,8-2,2 kg; R2 = 0,956-0,988), and therefore of greater predictive ability, than the rest of equations described in the international literature to date.El objetivo de esta investigación es validar nuevas ecuaciones de regresión para estimar el valor de fuerza dinámica máxima absoluta (1RM) mediante test de máximo número de repeticiones hasta el fallo muscular (nRM) ejecutados con técnica de parada o stop. Igualmente, se estudian los niveles de validez que presentan las ecuaciones que ya se encuentran actualmente definidas en la literatura internacional para estimar la magnitud de la carga (%1RM) y el valor de 1RM a partir de un test nRM en ejecuciones con técnica de parada. Los resultados indican que las nuevas ecuaciones propuestas en esta investigación [1RM en Press Banca = masa desplazada en kg (-0,01841*nRM)+0,981; 1RM en Sentadilla Completa = masa desplazada en kg (-0,01176*nRM)+0,975] muestran indicadores sustancialmente mejores de validez(ET = 1,8-2,2 kg; R2 = 0,956-0,988), y por lo tanto de mayor capacidad predictiva, que el resto de ecuaciones definidas en la literatura internacional hasta la fecha

Energetics and the magnetic state of Mn2 adsorbed on Au(111): Dimer bond distance dependence

"In this work we present a theoretical study of the adsorption Mn2 dimer on the Au(111) surface. Here we use the density functional theory to construct a map of adsorption energies, EA, of Mn2 on a Au(111) surface as a function of interatomic bond distance, , among Mn atoms. We employed a 4×4 supercell of Au(111) surface which lead us to reach values in the range from 2.6 to 6.8 Å. To make a full study of the adsorption energies we considered the antiferromagnetic (AFM) and ferromagnetic (FM) states of the Mn2 on the surface. The energy landscape contains local minima when the Mn atoms are adsorbed above triangular sites and barriers that the Mn adatoms have to overcome when they move across the Au(111) surface along various paths. Our results show that the lowest energy state corresponds to the state in which the Mn atoms are next-nearest neighbors and are antiferromagnetically coupled. Furthermore, all the local minima with higher bonding energy are also those in the antiferromagnetic state. Nevertheless we find a short interval in which the FM state has lower energy than the AFM one. Finally, scanning tunneling microscope simulations for various dimer configurations on surface are reported.

Evaluation of Mechanical Characteristics of Cement Mortar with Fine Recycled Concrete Aggregates (FRCA)

[EN] One of the growing demands in concrete manufacture is the availability of natural fine aggregates, which account for 35% to 45% of the total concrete. An alternative method of disposal of fine recycled concrete aggregates (FRCA) generated from demolition and construction waste (C&DW) is their usage in mortar and the development of recycled mortar. The main aim of this research work is to evaluate the viability of incorporating FRCA from urban C&DW for the manufacture of cement-based mortars. Simple processing techniques like washing and sieving are adopted to improve the FRCA quality. Physical and chemical characterization of ingredients is carried out. In total four mixes of 1:3 (cement: sand) mortar with partial replacement of normalized sand with FRCA (0%, 25%, 50%, and 100%) are evaluated for mechanical properties. Water to cement ratio for all four mortar mixes are determined by fixed consistency. Mechanical and physical properties like density, compressive strength, and flexural strength are studied for various curing periods, and the result is that the optimum usage of FRCA is 25% based on a 90-day curing period.SIReutiliza S.L. for offering the recycled and natural aggregate used in this study free of cost. Eduardo Torroja Institute for Construction Science and FCT for financial support

Emulación del sistema músculo-esqueletal y el control de movimiento en una plataforma experimental

Muchos fisiólogos han observado que el músculo humano o animal es una especie de tejido elástico (como un muelle) con componentes contráctiles, los cuales dan una longitud de umbral modificable neuralmente para el desarrollo de fuerzas. La determinación de las fuerzas del músculo durante el movimiento no es solamente esencial para el análisis de las cargas internas que actúan en los huesos y articulaciones, si no que también contribuyen ha entender más profundamente los controladores neuronales. Los sistemas de control biológicos han sido estudiados como una posible inspiración para la construción de controladores de sistemas robóticos. En este trabajo, se diseño e implemento un sistema biomecánico que tiene propiedades mécanicas casi similares a las de un brazo humano o animal. En este sistema se implementaron modelos matemáticos del músculo biológico, para la generación de fuerzas en el músculo esqueletal total. Además, se desarrollo una red cortical para el control de movimientos voluntarios con restricciones neurofisiológicas y psicofísicas motoras. El controlador neuronal es propuesto para realizar el seguimiento de trajectorias deseadas en la articulación de un simple eslabón controlado por un par de actuadores agonista-antagonista con propiedades musculares. El sistema es capaz de ejecutar movimientos de alcance voluntarios, con perfiles de velocidad en forma de campana bajo perturbaciones. Los resultados experimentales muestran que el sistema presenta las propiedades básicas del músculoesqueletal las cuales son las relaciones fuerza-longitud y fuerza-velocidad. El controlador neuronal permite controlar los movimientos deseados y compesar las fuerzas externas.Se agradece el apoyo recibido por los miembros del grupo de investigación de Neurotecnología, Control y Robótica (NEUROCOR) del departamento de Ingeniería de Sistemas y Automática de la Universidad Politécnica de Cartagena. Este trabajo fue financiado en parte por la CICYTTIC99- 0446-C02-01, y por el proyecto SYNERAGH - BRE2-CT980797 BRITE EURAM- de Investigación Básica

Spatio-temporal variability of droughts in Bolivia: 1955-2012

In this study, the spatio-temporal variability and trends of droughts across Bolivia between 1955 and 2012 were investigated using two climate drought indices: the Standardized Precipitation Index (SPI), which is based on precipitation data, and the Standardized Precipitation Evapotranspiration Index (SPEI), which is based on the difference between the precipitation and the reference evapotranspiration (ETo). We found that the average drought conditions across the country showed a temporal behaviour mainly characterized by decadal variations. The spatial pattern of drought evolution showed marked differences between the Amazonian region and the Bolivian Altiplano. Both regions showed different drought periods, a lower frequency of drought variability in the Amazon region and trends towards drier conditions in the Altiplano, mainly due to a higher atmospheric water demand as a consequence of increased ETo. We also showed that inclusion of ETo, obtained from maximum and minimum temperature records, increased the spatial heterogeneity of the drought evolution in relation to the evolution observed when only precipitation droughts were considered. The SPEI, the calculation of which includes precipitation and ETo, indicated intensification in drought severity in the last years analysed relative to the pattern found when precipitation droughts alone were considered, and also indicated an increase in the magnitude and duration of drought events. The potential for increasing drought conditions under various climate change scenarios is discussed. © 2015 Royal Meteorological Society.This work has been supported by research projects I-COOP H2O 2013CD0006: ‘Test multisectorial y actividades demostrativa sobre el potencial desarrollo de sistemas de monitorización de sequías en tiempo real en la región del oeste de Sudamérica’ financed by the Spanish National Research Council (CSIC), CGL2011-27574-CO2-02 financed by the Spanish Commission of Science and Technology and FEDER, ‘Demonstration and validation of innovative methodology for regional climate change adaptation in the Mediterranean area (LIFE MEDACC)’ financed by the LIFE programme of the European Commission, C.A.-M. received a postdoctoral fellowship # JCI-2011-10263. A.S.-L. is supported by the ‘Secretaria per a Universitats i Recerca del Departament d'Economia i Coneixement, de la Generalitat de Catalunya i del programa Cofund de les Accions Marie Curie del 7è Programa marc d'R + D de la Unió Europea’ (2011 BP-B 00078) and the postdoctoral fellowship # JCI-2012-12508.Peer Reviewe

Monitoring the growth of a microbubble generated photothermally onto an optical fiber by means Fabry–Perot interferometry

In the present paper, we show the experimental measurement of the growth of a microbubble created on the tip of a single mode optical fiber, in which zinc nanoparticles were photodeposited on its core by using a single laser source to carry out both the generation of the microbubble by photothermal effect and the monitoring of the microbubble diameter. The photodeposition technique, as well as the formation of the microbubble, was carried out by using a single-mode pigtailed laser diode with emission at a wavelength of 658 nm. The microbubble’s growth was analyzed in the time domain by the analysis of the Fabry–Perot cavity, whose diameter was calculated with the number of interference fringes visualized in an oscilloscope. The results obtained with this technique were compared with images obtained from a CCD camera, in order to verify the diameter of the microbubble. Therefore, by counting the interference fringes, it was possible to quantify the temporal evolution of the microbubble. As a practical demonstration, we proposed a vibrometer sensor using microbubbles with sizes of 83 and 175 m as a Fabry–Perot cavity; through the time period of a full oscillation cycle of an interferogram observed in the oscilloscope, it was possible to know the frequency vibration (500 and 1500 Hz) for a cuvette where the microbubble was created.CONACyT (FOINS) Grant No. 2319Fondo Sectorial de Investigación para la Educación Grant No. A1-S-28440

Sperm chromatin dispersion by formaldehyde in Wistar rats

Formaldehyde (FA) is an environmental xenobiotic, which is genotoxic and carcinogenic to humans and animals; it induces DNA damage, mutations, and clastogenicity during critical cytogenetic events. FA-mediated oxidative stress is an important mechanism that has been associated with the induction of cytotoxic and genotoxic damage. Therefore, the objective of this study was to evaluate the dispersion of sperm chromatin and reproductive parameters induced by exposure to different concentrations of FA in Wistar rats. Compared to the percentage of sperm with fragmented DNA in the control group (18.10 ± 8.62%), the percentage of sperm with fragmented DNA increased following exposure to 5, 10, and 30 mg FA/kg body weight (29.60 ± 8.44, 85.20 ± 20.94 and 96.0 ± 7.87, respectively; P = 0.0001). Histopathological alterations were evident, especially in the seminiferous tubules. In conclusion, this study provides experimental evidence concerning the genotoxicity of FA, with particular reference to the decreased sperm concentration and motility and increased dispersion of DNA chromatin in rats

SPROUTY-2 represses the epithelial phenotype of colon carcinoma cells via upregulation of ZEB1 mediated by ETS1 and miR-200/miR-150

SPROUTY-2 (SPRY2) is a modulator of tyrosine kinase receptor signaling with receptor- and cell type-dependent inhibitory or enhancing effects. Studies on the action of SPRY2 in major cancers are conflicting and its role remains unclear. Here we have dissected SPRY2 action in human colon cancer. Global transcriptomic analyses show that SPRY2 downregulates genes encoding tight junction proteins such as claudin-7 and occludin and other cell-to-cell and cell-to-matrix adhesion molecules in human SW480- ADH colon carcinoma cells. Moreover, SPRY2 represses LLGLL2/HUGL2, PATJ1/INADL and ST14, main regulators of the polarized epithelial phenotype, and ESRP1, an epithelial-to-mesenchymal transition (EMT) inhibitor. A key action of SPRY2 is the upregulation of the major EMT inducer ZEB1, as these effects are reversed by ZEB1 knock-down by means of RNA interference. Consistently, we found an inverse correlation between the expression level of claudin-7 and those of SPRY2 and ZEB1 in human colon tumors. Mechanistically, ZEB1 upregulation by SPRY2 results from the combined induction of ETS1 transcription factor and the repression of microRNAs (miR-200 family, miR-150) that target ZEB1 RNA. Moreover, SPRY2 increased AKT activation by epidermal growth factor (EGF) whereas AKT and also Src inhibition reduced the induction of ZEB1. Altogether, these data suggest that AKT and Src are implicated in SPRY2 action. Collectively, these results show a tumorigenic role of SPRY2 in colon cancer that is based on the dysregulation of tight junction and epithelial polarity master genes via upregulation of ZEB1. The dissection of the mechanism of action of SPRY2 in colon cancer cells is important to understand the upregulation of this gene in a subset of patients with this neoplasia that have poor prognosis.This study was supported by the Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional (FEDER) (grant SAF2013-43468-R to A.M., SAF2011-29530 to F.X.R.); FEDERInstituto de Salud Carlos III (RD12/0036/0021 to A.M. and J.M.R., RD12/0036/0034 to F.X.R., RD12/0036/0016 to M.S., RD12/0036/0012 to H.G.P., RD06/0020/0003, PS09/00562 and PI13/00703 to J.M.R.); Comunidad de Madrid (S2010/BMD-2344 Colomics2 to A.M.); Fundación Científica de la Asociación Española contra el Cáncer (to J.M.R.); U.S. Department of Defense (CA093471 and CA110602 to E.H.); National Institutes of Health/National Cancer Institute (1R01CA155234-01 to E.H.); National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases (1R21AR062239-01 to E.H.); and the Melanoma Research Alliance (to E. H.)

High-resolution genome screen for bone mineral density in heterogeneous stock rat

We previously demonstrated that skeletal mass, structure, and biomechanical properties vary considerably in heterogeneous stock (HS) rat strains. In addition, we observed strong heritability for several of these skeletal phenotypes in the HS rat model, suggesting that it represents a unique genetic resource for dissecting the complex genetics underlying bone fragility. The purpose of this study was to identify and localize genes associated with bone mineral density in HS rats. We measured bone phenotypes from 1524 adult male and female HS rats between 17 and 20 weeks of age. Phenotypes included dual-energy X-ray absorptiometry (DXA) measurements for bone mineral content and areal bone mineral density (aBMD) for femur and lumbar spine (L3-L5), and volumetric BMD measurements by CT for the midshaft and distal femur, femur neck, and fifth lumbar vertebra (L5). A total of 70,000 polymorphic single-nucleotide polymorphisms (SNPs) distributed throughout the genome were selected from genotypes obtained from the Affymetrix rat custom SNPs array for the HS rat population. These SNPs spanned the HS rat genome with a mean linkage disequilibrium coefficient between neighboring SNPs of 0.95. Haplotypes were estimated across the entire genome for each rat using a multipoint haplotype reconstruction method, which calculates the probability of descent for each genotyped locus from each of the eight founder HS strains. The haplotypes were tested for association with each bone density phenotype via a mixed model with covariate adjustment. We identified quantitative trait loci (QTLs) for BMD phenotypes on chromosomes 2, 9, 10, and 13 meeting a conservative genomewide empiric significance threshold (false discovery rate [FDR] = 5%; p < 3 × 10(-6)). Importantly, most QTLs were localized to very small genomic regions (1-3 megabases [Mb]), allowing us to identify a narrow set of potential candidate genes including both novel genes and genes previously shown to have roles in skeletal development and homeostasis