Diffusion dynamics on multiplex networks

We study the time scales associated to diffusion processes that take place on multiplex networks, i.e. on a set of networks linked through interconnected layers. To this end, we propose the construction of a supra-Laplacian matrix, which consists of a dimensional lifting of the Laplacian matrix of each layer of the multiplex network. We use perturbative analysis to reveal analytically the structure of eigenvectors and eigenvalues of the complete network in terms of the spectral properties of the individual layers. The spectrum of the supra-Laplacian allows us to understand the physics of diffusion-like processes on top of multiplex networks.Comment: 6 Pages including supplemental material. To appear in Physical Review Letter

Threading Through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers

In this work we study the reinforcement of polymers by mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare the mechanical properties of fibers made of polymers and of composites with pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked derivatives of SWNTs (MINTs) and the corresponding supramolecular models. Improvements of both Young's modulus and tensile strength of up to 200 % were observed for the polystyrene-MINTs samples with an optimized loading of just 0.01 wt.%, while the supramolecular models with identical chemical composition and loading showed negligible or even detrimental influence. This behavior is found for three different types of SWNTs and two types of macrocycles. Molecular dynamics simulations show that the polymer adopts an elongated conformation parallel to the SWNT when interacting with MINT fillers, irrespective of the macrocycle chemical nature, whereas a more globular structure is taken upon facing with either pristine SWNTs or supramolecular models. The MINT composite architecture thus leads to a more efficient exploitation of the axial properties of the SWNTs and of the polymer chain at the interface, in agreement with experimental results. Our findings demonstrate that the mechanical bond imparts distinctive advantageous properties to SWNT derivatives as polymer fillers.Comment: 39 pages, 19 figure

Use of a new ocular insert versus conventional mydriasis in cataract surgery

Background. To compare the efficacy and safety of a new ocular insert versus conventional mydriasis in cataract surgery. Methods. We selected 70 patients undergoing cataract surgery. Thirty five patients (Group 1) received instillation of mydriatic drops (tropicamide 1%, phenylephrine 10%, and cyclopentolate 1%) prior to surgery, and 35 patients (Group 2) had a Mydriasert insert (Théa Pharma) (0.28¿mg of tropicamide and 5.4¿mg of phenylephrine hydrochloride) placed in the inferior fornix. Pupil size before and after surgery, blood pressure, and heart rate were measured. Results. Before surgery, pupil diameter was ¿mm in Group 1 and in Group 2 ( ). Twenty four hours after surgery, pupil diameter was ¿mm in Group 1 and in Group 2 ( ). There were no statistically significant differences in blood pressure or heart rate between groups. Conclusions. The effect of the Mydriasert insert was similar to conventional mydriatic agents. Pupil size was restored to normal faster when using the Mydriasert insert compared with conventional mydriatic agents for pupil dilation

Chemical physics insight of PPy-based modified ion exchange membranes: a fundamental approach

Four commercially available, cost-effective ion exchange membranes (two cationic and two anionic exchange membranes, CEMs and AEMs, respectively) were modified to mitigate crossover phenomena of the redox active species typically observed in Aqueous Organic Redox Flow Batteries (AORFB) systems. The modification strategy was carried out using a pyrrole(Py)-based polymer which successfully reduced the permeation of two redox active organic molecules, a viologen derivative (named BP7 throughout this study) and TEMPOL, by an order of magnitude. Additionally, modified membranes showed not significant changes in ion conductivity, with negligible effect on the electrical conductivity of the membranes at a given conditions. The morphology, physicochemical, mechanical, and electrochemical properties of the membranes were determined to evaluate the impact of these modifications. AEMs modified in this manner were found to have optimal properties, showing an increase in ion exchange capacity while maintaining excellent mechanical stability and unaltered permselectivity. Additionally, the diffusion boundary layer of these AEMs was slightly extended, which suggests a greater double layer stability for ion exchange processes than in the case of CEMs. Our work shows that these modified membranes could be an appealing approach for AORFB applicationsThis work has been funded by the European Union under the HIGREEW project, Affordable High-performance Green Redox Flow batteries (Grant agreement no. 875613). H2020: LC-BAT-4-2019875613

Occupational exposures and distribution of natural radionuclides in phosphoric acid production by the wet process (Spain)

The industries devoted to the production of phosphoric acid use as a raw material large amount of phosphate rock (PR), which– depending on its geological origin –could be enriched in natural radionuclides either from the uranium or thorium series. In addition, and depending of the process used, different by-products also enriched in natural radionuclides are formed. For this reason, these types of industries are considered as one of the most representative examples where NORM and TENORM is handled, and consequently where a detailed radiological study for protection of the workers is needed.In Spain, a quite large industrial complex is located in an estuary in the surroundings of Huelva town (SW of Spain, see Figure 1), with two big factories devoted to the production of phosphoric acid through the so-called “wet-acid process” (see details in Section 2). In these factories, two types of phosphatic ores are processed: a) sedimentary marine origin phosphate ore from Morocco, and b) igneous origin phosphate ore from Kola (Russia). The Moroccan phosphorites are characterised for their high uranium concentrations, ranging 100-150 ppm, while the igneous phosphate rocks from Kola have clearly lower levels of this element. In opposition, the Kola phosphate rocks present concentrations of the 232Th-series in a factor up to 3 to 5 higher than in word average soils, while the Moroccan phosphorites contain clearly lower concentrations from this natural series [1]In both raw materials, both the 238Uand the 232Th are in secular equilibrium with their daughters. Nevertheless, during the application of the industrial process, the aforementioned secular equilibrium is broken, suffering the different radionuclides their redistributions between intermediate products according to their respective chemical characteristics [2]. This fact need to be taken into consideration for a proper radiological study inside the factories

Estudio baropodométrico en pacientes tratados mediante artroplastia total de rodilla

La patología artrósica de la rodilla condiciona una disminución de la carga del miembro afecto y un patrón de apoyo con predominio generalmente del arco externo. El propósito de este estudio es determinar si existe una modificación significativa de este patrón tras la implantación de una artroplastia total de rodilla (ATR) primaria, recogiendo las presiones plantares de ambos pies mediante baropodometría electrónica previamente y 4 meses tras la cirugía, tanto en estática como en dinámica. Así, se analizan las presiones plantares de 30 pacientes, 21 mujeres y 9 hombres, intervenidos de ATR primaria en el Hospital Universitario Doctor Peset entre los años 2013 y 2015. También se ha determinado si existe una corrección del eje anatómico tras la cirugía. Utilizando test no paramétricos (test de Wilcoxon para datos apareados, U de Mann-Whitney), observamos una modificación significativa de dicho ángulo desde valores medianos de 1.2º de varo a 4.9º de valgo en el postoperatorio, una disminución mediana de la presión plantar en ambos pies y una redistribución de la carga axial, aumentando en el miembro intervenido. Concluimos que, 4 meses tras la cirugía, se produce una tendencia a la “normalización” de la pisada en pacientes en los que se ha implantado una ATR, condicionado tanto por la mejora del dolor y la funcionalidad como por la realineación del eje.Knee osteoarthritis determines a decrease of the load of the affected limb and a pattern usually dominance of external support plantar arc. The purpose of this study is to determine whether a significant change in this pattern is? after implantation of a primary total knee arthroplasty (TKA), measuring plantar pressures in both feet by electronic baropodometry previously and 4 months after surgery, in static and dynamic. Plantar pressures of 30 patients are analyzed, who underwent primary TKA at the University Hospital Doctor Peset between 2013 and 2015. In addition, it has also been determined if there is a correction on the anatomical axis after surgery. Using nonparametric test (Wilcoxon test for paired data, U Mann Whitney), we observed a significant change in the angle from median values of 1.2º varus to 4.9º valgus postoperatively, a median decrease of plantar pressure in both feet and a redistribution of axial load, increasing in the operated limb. We conclude that, 4 months after surgery, there is a tendency to “normalization” of the tread in patients undergoing TKA. This is conditioned by improving pain and function as axis realignment occurs

Zircon to monazite phase transition in CeVO4

X-ray diffraction and Raman-scattering measurements on cerium vanadate have been performed up to 12 and 16 GPa, respectively. Experiments reveal that at 5.3 GPa the onset of a pressure-induced irreversible phase transition from the zircon to the monazite structure. Beyond this pressure, diffraction peaks and Raman-active modes of the monazite phase are measured. The zircon to monazite transition in CeVO4 is distinctive among the other rare-earth orthovanadates. We also observed softening of external translational Eg and internal B2g bending modes. We attributed it to mechanical instabilities of zircon phase against the pressure-induced distortion. We additionally report lattice-dynamical and total-energy calculations which are in agreement with the experimental results. Finally, the effect of non-hydrostatic stresses on the structural sequence is studied and the equations of state of different phases are reported.Comment: 45 pages, 8 figures, 8 table

The Gallecs trial, a mid-term experiment on reduced tillage, fertilisation and green manure in Mediterranean dryland arable cropping systems

Conservation agriculture and organic farming are two alternative strategies aimed at improving soil fertility in arable cropping systems through reducing tillage intensity, maintaining year-round soil cover and increasing nutrient recycling, using farmyard and green manures. However, the reduction of tillage intensity can increase weed infestation and decrease nutrient availability. The mid-term "Gallecs" trial (Catalonia) was established in autumn 2011 at Gallecs, a periurban agricultural area near Barcelona. The effects of tillage (mouldboard versus chisel ploughing), fertilisation by farmyard manure (without versus with) and green manure (without versus with) on soil fertility indicators, weed abundance and grain crop yields were studied in a 4-years cereal-legume rotation for human consumption under organic farming conditions in the Mediterranean region (Catalonia, Spain)

Biological and chemical factors controlling the patchy distribution of soil water repellency among plant species in a Mediterranean semiarid forest

Natural soil water repellency is a property that has already been observed in forest soils and is characterized by its patchy distribution. There are many factors involved in its development. In this work, we have studied a large number of chemical and biological factors under the influence of different plant species (. Pinus halepensis, Quercus rotundifolia, Cistus albidus and Rosmarinus officinalis) to learn which has the greatest responsibility for its presence and persistence in the top-soil layer. We observed strong and significant correlations between ergosterol, glomalin related soil protein (GRSP), extractable lipids, soil organic matter (SOM) content and water repellency (WR). Our results suggested lipid fraction as the principal factor. Moreover, apart from Pinus, fungal biomass seems to be also related to the SOM content. Soil WR found under Pinus appears to be the most influenced by fungi. Quality of SOM, to be precise, lipid fraction could be responsible for WR and its relationship with fungal activity.Ministerio de Economía y Competitividad CGL2010- 21670-C02-01, CGL2012-38655-C04-0