Preliminary structural and seismic performance assessment of the Mosque-Cathedral of Cordoba: The Abd al-Rahman I sector

This manuscript discusses some preliminary results on the structural and the seismic performance of the Mosque-Cathedral of Cordoba, a UNESCO World Heritage. The area is characterized by a moderate seismic hazard. The building was built from the 8th to the 16th century and it has undergone several transformations. Owing to the complexity of the building, this work has focused on the assessment of the Abd al-Rahman I sector, which is the most aged part of the complex. For that, first, a 3D numerical finite element model of the sector has been done in the OpenSees framework and calibrated. To do so, an experimental non-destructive campaign has been carried out. Second, the model has been used to evaluate the structural behaviour, under vertical and horizontal loads, considering different scenarios. Finally, the crack patterns and the seismic safety have been obtained. The results showed that the numerical damage obtained for the gravitational loads is in good agreement with the data collected from the in situ surveys. Also, particular attention should be paid to the cymatiums, as they are the most demanded part of the system. Regarding its seismic performance, the building presents a higher capacity in the direction of the arcades. For the seismic demand, slight damage is expected in both principal directions of the building, which could be easily repaired. Damage concentration is expected in the contact between the perimetral wall and the arcades. This work has expanded the study of the features of the Mosque-Cathedral of Cordoba to the structural and seismic analysis with advanced numerical FE computing, which has not been done to date. To the authors’ knowledge, this is the first time that a macro-modelling approach with solid elements is presented for the seismic assessment of heritage buildings using the OpenSees framework. The methodology to do so is also presented. Apart from showing how advanced numerical analyses can provide useful information to assess the existing damage on monumental buildings, this work aims at contributing to the assessment of the vulnerability and the safety of one of the most emblematic mosque-like buildings of the world.20 página

Evaluation of bone mineral with dexa in youth soccer players

El objetivo de este estudio fue evaluar la densidad mineral ósea (DMO) y el contenido mineral óseo (CMO) de los segmentos corporales durante un periodo de entrenamiento de seis meses. Se evaluaron a 41 futbolistas juveniles profesionales en dos momentos, una al comienzo (TI) y otra al final (TF) de la intervención con el equipo de absorciometría dual de rayos X (DEXA). Se lograron aumentos significativos en la DMO en los segmentos corporales de la cadera, columna lumbar, triangulo de Ward, tronco y del cuerpo total (p<0.05). También se obtuvo un incremento significativo del CMO en la cadera, columna lumbar, pierna, tronco y costillas (p<0.05). El entrenamiento de futbol fortaleció el CMO y la DMO del hueso de la extremidad inferior y de la caja torácica, con lo cual el fútbol podría ser una actividad útil para la mejorar la mineralización y fortalecimiento del hueso, para prevenir lesiones y fracturasThe objective of this study was to assess bone mineral density (BMD) and bone mineral content (BMC) of body segments for a six months training period. 41 professional youth players were evaluated in two moments, one at the beginning (TI) and another at the end (TF) of the intervention with the dual energy x-ray absorptiometry equipment (DEXA). Significant increases in BMD were achieved in the body segments of the hip, lumbar spine, ward triangle, trunk and total body (p <0.05). There was also a significant increase in BMC in the hip, lumbar spine, leg, trunk and ribs (p <0.05). Soccer training strengthened the BMC and BMD of the lower limb bone and the rib cage, which could be a useful activity to improve bone mineralization and strengthening, to prevent injuries and fracture

Proline cis-​trans isomerization and its implications for the dimerization of analogues of cyclopeptide stylostatin 1: a combined computational and experimental study

Cis and trans proline conformers are often associated with dramatic changes in the biological function of peptides. A slow equilibrium between cis and trans Ile-Pro amide bond conformers occurs in constrained derivatives of the native marine cyclic heptapeptide stylostatin 1 (cyclo-(NSLAIPF)), a potential anticancer agent. In this work, four cyclopeptides, cyclo-(NSTAIPF), cyclo-(KSTAIPF), cyclo-(RSTAIPF) and cyclo-(DSTAIPF), which are structurally related to stylostatin 1, are experimentally and computationally examined in order to assess the effect of residue mutations on the cis-trans conformational ratio and the apparent capacity to form dimeric aggregates. Primarily, cyclo-(KSTAIPF) and cyclo-(RSTAIPF) showed specific trends in circular dichroism, MALDI-TOF and HPLC purification experiments, which suggests the occurrence of peptide dimerization. Meanwhile, the NMR spectrum of cyclo-(KSTAIPF) indicates that this cyclopeptide exists in the two slow-exchange families of conformations mentioned above. Molecular dynamics simulations combined with quantum mechanical calculations have shed light on the factors governing the cis/trans conformational ratio. In particular, we have found that residue mutations affect the internal hydrogen bond pattern which ultimately tunes the cis/trans conformational ratio and that only trans conformers are capable of aggregating due to the shape complementarity of the two subunits

Corrosion and tribocorrosion behavior of Ti-Alumina composites

This work focus on the corrosion and wear properties of titanium reinforced with 1% wt. alumina particles, produced by a combination of colloidal techniques and powder metallurgy. The alumina particles were added to control the grain growth of titanium during sintering, and simultaneously to increase hardness and wear resistance. Colloidal techniques permitted a homogeneous dispersion of alumina particles on the surface of fine Ti particles by the formulation of stable aqueous suspensions that were further processed by spray-dry to obtain spherical granules with improved compressibility. Ti-Alumina samples were produced by uniaxial pressing of granules and vacuum sintering leading to materials with homogeneous microstructure, a reduction of grain size higher than 50 % with respect to pure titanium, and a sensible increase in hardness. But the addition of ceramic particles can also have an influence on the corrosion behavior that is one of the most interesting properties of titanium alloys, and on wear resistance, that is one of the drawbacks of Ti. Moreover, the study of simultaneous action of wear and corrosion (tribocorrosion) is an area of highest interest in applications like biomedical or automotive. The corrosion behavior was evaluated by Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PP) in NaCl at two concentrations (0.9 % and 3.5 %) and temperatures (37 °C, and room temperature). Tribocorrosion tests were performed using a reciprocating ball-on-plate tribometer where a 10 mm diameter alumina ball was used as counter material, and 10 N normal load was applied during 30 min in the same concentrations and temperatures of NaCl as in the static corrosion test s. The results showed a clear improvement of wear resistance on the composite without reducing the corrosion behavior in both conditions.(undefined)info:eu-repo/semantics/publishedVersio

Optoelectrical analysis of TCO Silicon oxide double layers at the front and rear side of silicon heterojunction solar cells

Silicon Heterojunction has become a promising technology to substitute passivated emitter and rear contact PERC solar cells in pursuance of lower levelized cost of electricity through high efficiency devices. While high open circuit voltages and fill factors are reached, current loss related to the front and rear contacts, such as the transparent conductive oxide TCO layers is still a limiting factor to come closer to the efficiency limit of silicon based solar cells. Furthermore, reducing indium consumption for the TCO has become mandatory to push silicon heterojunction technology towards a terawatt scale production due to material scarcity and costs. To address these issues dielectric layers, such as silicon dioxide or nitride cappings are implemented to reduce TCO thicknesses both diminishing parasitic absorption and material consumption. However, reducing the TCO thickness comes in cost of resistive losses. Furthermore, the TCO properties do vary with thickness and neighboring layer configuration altering the optimization frame of the device. In this paper we present a detailed analysis to quantify the optoelectrical losses trade off associated to the TCO thickness reduction in such layer stacks. Through the analysis we show and explain why experimental bifacial cells with 20 nm front and rear TCO perform at a similar level to reference cells with 75 nm under front and rear illumination reaching efficiency close to 24 at 92 bifaciality. We present as well a simple interconnection method via screen printing metallization to implement a thin TCO silicon dioxide silver reflector enhancing current density from 39.6 to 40.4 mA cm2 without compromising resistive losses resulting in a 0.2 absolute solar cell efficiency increase from a bifacial design 23.5 23.7 . Finally, following this approach we present a certified champion cell with an efficiency of 24.

The response of the tandem pore potassium channel TASK-3 (K2P9.1) to voltage : gating at the cytoplasmic mouth

Although the tandem pore potassium channel TASK-3 is thought to open and shut at its selectivity filter in response to changes of extracellular pH, it is currently unknown whether the channel also shows gating at its inner, cytoplasmic mouth through movements of membrane helices M2 and M4.We used two electrode voltage clamp and single channel recording to show that TASK-3 responds to voltage in a way that reveals such gating. In wild-type channels, Popen was very low at negative voltages, but increased with depolarisation. The effect of voltage was relatively weak and the gating charge small, ∼0.17.Mutants A237T (in M4) and N133A (in M2) increased Popen at a given voltage, increasing mean open time and the number of openings per burst. In addition, the relationship between Popen andvoltagewas shifted to lesspositive voltages. Mutation of putative hinge glycines (G117A, G231A), residues that are conserved throughout the tandem pore channel family, reduced Popen at a given voltage, shifting the relationship with voltage to a more positive potential range. None of these mutants substantially affected the response of the channel to extracellular acidification. We have used the results from single channel recording to develop a simple kinetic model to show how gating occurs through two classes of conformation change, with two routes out of the open state, as expected if gating occurs both at the selectivity filter and at its cytoplasmic mouth

Topological and biomass balance approaches to analyzing food webs of Bahía Magdalena, Baja California Sur, Mexico

In this paper, we used two methodological approaches to analyze the structure and function of a trophic web in the temperate coastal lagoon of Bahía Magdalena, Baja California Sur, Mexico, which represents the largest wetland ecosystem along the west coast of the Baja California peninsula. Ecosystem structure was studied using a topological approach, while ecosystem functioning was analyzed using a biomass balance model. Connectance values indicated a low number of functional group interactions, consistent with the range proposed for similar marine trophic webs. This pattern may reflect incorporation of a few functional groups clustered along the trophic web. Results would vary if the model included more functional groups or different levels of aggregation, since aggregation and diversity strongly influence the base of the food web. Topological results suggest that trophic web structure depends primarily on lower and intermediate trophic level organisms like macrobenthic invertebrates, penaeid shrimp and marine turtles. Balance biomass model results suggest that trophic groups positioned on the first level most strongly support Bahía Magdalena trophic web functioning. In particular, the pelagic red crab (Pleurocondes planipes) transfers energy between basal and upper levels of the food web (a wasp-waist energy control). When compared to ecosystems at different latitudes, the results indicate that the Bahía Magdalena ecosystem is still in a developmental phase, wherein trophic web functioning depends largely on the balance between energy flows originating from primary producers and those originating from detrital pathways. While these results are preliminary, they demonstrate the potential of combined topological and biomass approaches in analyzing highly organized ecosystems. The combined approach can make both theoretical and empirical predictions about the functional response of real systems to structural changes, thus enhancing evidence-based methods for ecosystem management