TiO2 surfaces support neuron growth during electric field stimulation

The authors are grateful to Francisco Almendros and Ismael Santamaría for help in preparation of the TiO2 substrates. We acknowledge the European Project NERBIOS (NEST/STREP (FP6), 028473-2) for financial support. Maria Canillas acknowledges the JAE-CSIC program of her PhD scholarship. Berta Moreno acknowledges the Fondo Social Europeo and the CSIC for the funding of her JAE Doc contract. Ann Rajnicek acknowledges financial support from The Development Trust at the University of Aberdeen to the Aberdeen Spinal Research Group, including support from the Scottish Rugby Union.Peer reviewedPostprin

Scavenging activity of Magnéli phases as a function of Ti(4+)/Ti(3+) ratios

TiO2 is able to scavenge reactive oxygen and nitrogen species (ROS and RNS) in the absence of light. The scavenging mechanism has been related to the chemistry of defects (oxygen vacancy reduced oxidation states of Ti) but it is still unknown. This study describes the ROS scavenging activity of different titanium oxide phases and relates their scavenging activities with the Ti4+/Ti3+ molar ratio as well as the band gap value. The Ti5O9 phase, with a mixture of both oxidation states, presented a substantially higher percentage of 2,2-diphenyl-1-picrylhydracyl radicals (DPPH) eliminated per m2 of specific surface area in comparison to phases with predominant oxidation states Ti4+ or Ti3+ such as TiO2 and Ti2O3, respectively. The obtained results indicate that the DPPH scavenging mechanism corresponds to a catalytic process on the Ti5O9 surface which is facilitated by the presence of charges that can easily move through the material. The mobility of charges and electrons in the semiconductor surface, related to the presence of oxidation states Ti4+ and Ti3+ and a small band gap, could create an attractive surface for radical species such as DPPH. This puts forward Ti5O9 as a promising candidate coating for implantable biomedical devices, as an electrode, since it can cushion inflammatory processes which could lead to device encapsulation and, consequently, failure.The authors would like to thank the Fundación General CSIC and Obra Social “La Caixa” (Project BIOAMD) for providing financial support to this work. Dr Canillas acknowledges the financial support received from the CSIC for her PhD JAEpre grant and Dr Moreno is grateful to the Fondo Social Europeo and CSIC for her JAEDoc contract

Validating GIC modeling in the Spanish power grid by differential magnetometry

series of experiences and recommendations are presented concerning the derivation of geomagnetically induced currents (GIC) by use of the differential magnetometry method (DMM) under power lines. This indirect technique, intended to obtain observations to validate GIC models, is an alternative to measuring the current flow in the transformer neutrals. It is a non-intrusive and autonomous technique, as the procedure does not depend on the grid operator. In contrast, the selection of suitable sites devoid of human interferences, the need for power to supply the magnetometer, the data acquisition and transmission system, along with the choice of the appropriate instrumentation are difficulties that make not just any site suitable for installation and often require costly solutions. We focus on the methodology followed to estimate the GIC flowing in several transmission lines of the Spanish power grid with the aim of validating our GIC models, and we share our experience on the installation of the measuring points. Uncertainty inherent in the DMM is assessed, showing that noise is the main handicap, although it can be minimized with appropriate filtering. According to such experience, on some occasions only total DC currents above a significant fraction of 1 A give magnetic signatures well above the noise level, so this figure can roughly be considered as the threshold limit for detection. The low solar activity, combined with the mid-latitude condition of Spain, limited the significance of available recorded data, but we can already report and analyze the results for several minor geomagnetic storms

Structure vs. excitonic transitions in self-assembled porphyrin nanotubes and their effect on light absorption and scattering

The optical properties of diprotonated meso-tetrakis(4-sulphonatophenyl)porphyrin (TPPS4) J-aggregates of elongated thin particles (nanotubes in solution and ribbons when deposited on solid interfaces) are studied by different polarimetric techniques. The selective light extinction in these structures, which depends on the alignment of the nanoparticle with respect to the polarization of light, is contributed by excitonic absorption bands and by resonance light scattering. The optical response as a function of the polarization of light is complex because, although the quasi-one-dimensional structure confines the local fields along the nanotube axis, there are two orthogonal excitonic bands, of H- and J-character, that can work in favor of or against the field confinement. Results suggest that resonance light scattering is the dominant effect in solid state preparations, i.e. in collective groups (bundles) of ribbons but in diluted solutions, i.e. with isolated nanotubes, the absorption at the excitonic transitions remains dominant and linear dichroism spectra can be a direct probe of the exciton orientations. Therefore, by analyzing scattering and absorption data we can determine the alignment of the excitonic bands within the nanoparticle, i.e. of the orientation of the basic 2D porphyrin architecture in the nanoparticle. This is a necessary first step for understanding the directions of energy transport, charge polarization and non-linear optical properties in these materials

Synchrotron X-ray microdiffraction to study dental structures in Cretaceous crocodylomorphs

Synchrotron radiation X-ray microdiffraction (SR-μXRD) has been applied for the first time as a fundamental method of analysis to unveil crocodilian teeth growth and development. Teeth from a fossil crocodylomorph from the Upper Cretaceous site of Lo Hueco (Spain) and a modern crocodylian from the living species Crocodylus niloticus have been analysed. Both samples have been studied through Polarized Light Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy, Confocal Raman Spectroscopy, and SR-μXRD. Significant differences have been found in hydroxyapatite (HA) crystallite sizes and texture, and the evolution of these two features along teeth depth. The main differences observed in crystallite size are related to postdepositional processes and/or the environmental and functional pressures of teeth during crocodylomorph life, very different from that of the modern specimen. Regarding the crystalline texture in the tooth enamel, it can be linked to teeth functionality during crocodilian life, causing the directed growth of HA crystallites due to the mechanical stress to which they are subjectedThis work was funded by the projects PGC2018-099405-B-100 (Ministerio de Ciencia, Innovacion y Universidades); HAR2017- 82755-P, HAR2016-78036-P, HAR2016-74846-P, HAR2017-83004-P, CGL2015-66604, CGL2015-68363 and MAT2015-67593-P (Ministerio de Economía y Competitividad, Spain); and 201860E127 (CSIC

Cómo minimizar los cambios radiológicos laterales en la osteotomía valguizante de adición medial de rodilla

Objetivo: estudiar la relación entre posición del injerto en Osteotomía Valguizante de Adición (OVA) en rodilla, los cambios radiológicos experimentados por la rótula y la pendiente tibial y su correlación clínica. Material y métodos: estudio retrospectivo de 10 pacientes operados de OVA. Medimos el cambio experimentado tras la osteotomía en Índice de Catón y la pendiente tibial y su relación con la ubicación del injerto. Valoración clínica mediante test de Lisholm y WOMAC. Resultados: edad media de 49.5 años, seguimiento medio de 32,2 meses. Se observa un cambio estadísticamente significativo de 1,45º en la pendiente tibial y de 0,15 unidades (Índice Catón) en la altura de la patela, pero sin correlación con la clínica. La ubicación del injerto en el cuadrante posterior se halló en el 80% de los casos. Conclusión : la osteotomía valguizante de adición medial tiene buenos resultados clínicos. Los cambios en la pendiente tibial y en la patela son menores cuanto más posterior es la ubicación del injerto.Objectives: we investigated changes in patellar height and tibial inclination angle after open-wedge high tibial osteotomy, the effect of these changes on patient satisfaction and the correlation with the graft position. Methods: retrospective study of 10 knees who underwent open-wedge proximal tibial osteotomy with allograft and medial plate for medial compartment. Were measured pre- and postoperatively tibial inclination angle, and patellar height (Caton Index), and we study the correlation of these changes with the location of the graft. Clinical evaluations were made using the Lysholm and WOMAC score. Results: the mean age was 49.5 years, the mean follow up was 32,2 months. The mean increase in the tibial inclination angle was 1,45 ° (p<0.05) and the mean of decrease in patellar height was 0.15 Units Caton Index (p<0.05). There weren’t correlation between radiological changes and patients satisfaction. The graft localization was posterior in 80% of patients. Conclusion: the open-wedge tibial osteotomy has good results and high clinical satisfaction. Changes in the tibial slope and the patellar height are lower if the graft position is posterior

Relation between 2D/3D chirality and the appearence of chiroptical effects in real nanostructures.

The optical activity of fabricated metallic nanostructures is investigated by complete polarimetry. While lattices decorated with nanoscale gammadia etched in thin metallic films have been described as two dimensional, planar nanostructures, they are better described as quasi-planar structures with some three dimensional character. We find that the optical activity of these structures arises not only from the dissymmetric backing by a substrate but, more importantly, from the selective rounding of the nanostructure edges. A true chiroptical response in the far-field is only allowed when the gammadia contain these non-planar features. This is demonstrated by polarimetric measurements in conjunction with electrodynamical simulations based on the discrete dipole approximation that consider non-ideal gammadia. It is also shown that subtle planar dissymmetries in gammadia are sufficient to generate asymmetric transmission of circular polarized light

Reversible mechanical induction of optical activity in solutions of soft-matter nanophases

Nanophases of J-aggregates of several achiral amphiphilic porphyrins, which have thin long acicular shapes (nanoribbons), show the immediate and reversible formation of a stationary mechano-chiral state in the solution by vortex stirring, as detected by their circular dichroic signals measured by 2-modulator generallized ellipsometry. The results suggest that when a macroscopic chiral force creates supramolecular chirality, it also creates an enantiomeric excess of screw distortions, which may be detected by their excitonic absorption. An explanation on the effect of the shear flow gradients is proposed on the basis of the orientation of the rotating particles in the vortex and the size, shape, and mechanical properties of the nanoparticles

On the mechano-chiral effect of vortical flows on the dichroic spectra of 5-phenyl-10,15,20-tris(4-sulfonatophenyl)porphyrin J-aggregates

Phase-modulated ellipsometry of the J-aggregates of the title porphyrin shows that the material gives a true CD signal. This confirms that there is a real chiral transfer by mechanical forces, mediated by shear gradient flows, from the macroscopic to the electronic transition level. Dislocations in the structure of the aggregate could justify the formation of chirality at the level of the electronic transitions once the mesophases can be sculptured by hydrodynamic gradient flows

Synchrotron X-ray microdiffraction to study dental structures in Cretaceous crocodylomorphs

Synchrotron radiation X-ray microdiffraction (SR-μXRD) has been applied for the first time as a fundamental method of analysis to unveil crocodilian teeth growth and development. Teeth from a fossil crocodylomorph from the Upper Cretaceous site of Lo Hueco (Spain) and a modern crocodylian from the living species Crocodylus niloticus have been analysed. Both samples have been studied through Polarized Light Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy, Confocal Raman Spectroscopy, and SR-μXRD. Significant differences have been found in hydroxyapatite (HA) crystallite sizes and texture, and the evolution of these two features along teeth depth. The main differences observed in crystallite size are related to postdepositional processes and/or the environmental and functional pressures of teeth during crocodylomorph life, very different from that of the modern specimen. Regarding the crystalline texture in the tooth enamel, it can be linked to teeth functionality during crocodilian life, causing the directed growth of HA crystallites due to the mechanical stress to which they are subjected