Dispersión de rayos X aplicado al análisis de nanotubos de carbono, polímeros y nanocompuestos

[EN] In this review we will show that wide and small angle X-ray scattering techniques (WAXS and SAXS respectively) can be a valuable tool to characterize the structure of carbon nanotubes (CNT) and related CNT-polymer nanocomposites at different characteristic length scales. Ranging from single carbon nanotubes to aggregates of CNTs X-ray scattering may offer structural information which can be crucial in order to design new materials based on carbon nanotubes.[ES] En este trabajo de revisión mostramos que las técnicas de dispersión de rayos X a alto y bajo ángulo (WAXS y SAXS respectivamente) pueden ser una herramienta muy valiosa para caracterizar la estructura de nanotubos de carbono (CNT) y nanocompuestos CNT-polímero, en diferentes escalas de longitud. La dispersión de rayos X puede ofrecer información estructural en el rango desde nanotubos de carbono aislados, hasta agregados de CNT. Dicha información puede ser crucial de cara a diseñar materiales basados en nanotubos de carbono.The authors thank the financial support from the MCYT (grant MAT2005-01768), Spain. The help of G. Broza, Z. Roslaniec, K. Schulte, I. Sics, B. H. Hsiao, S. S. Funari in different parts of this work is gratefully acknowledge. M. C. G.-G. and A. N. are also grateful to the Ramón y Cajal Program for the support of this reserach­.Peer reviewe

Influence of a polymer membrane on the electrochemical determination of insulin in nanomodified screen printed carbon electrodes

Ajuts: the research was supported by the projects VEGA 1/0074/17 of the Slovak Scientific Grant Agency, APVV-16-0029 of the Slovak Research and Development Agency, and VVGS-PF-2018-795 and VVGS-PF-2018-794 of Pavol Jozef Šafárik University in Košice.Diabetes mellitus can be considered one of the most widespread diseases globally. Hence, the diabetes research is currently focused on developing an effective, low-cost sensor having high stability and suitable analytical characteristics. Screen printed carbon electrodes (SPCEs) embody ideal candidates for insulin determination due to the small area of the working electrode eliminating the solution volume required for the given purpose. Modification of SPCEs by using nanoparticles resulted in an increase of the working electrode surface area and formation of a higher number of active species. The aim of this paper is to examine the impact of a chitosan membrane on the electrochemical determination of insulin on NiO nanoparticles (NiONPs) and multi-walled nanotube (MWCNTs) modified SPCE (NiONPs/MWCNTs/SPCE). This study is primarily conceived to compare the analytical characteristics and stability of NiONPs/chitosan-MWCNTs/SPCE and NiONPs/MWCNTs/SPCE. An electrode modified with chitosan displays a wider linear range, one of 0.25 μM - 5 μM (R² 0.997); a lower limit of detection, 94 nM; a high sensitivity (0.021 μA/μM) and better stability than that of an electrode without chitosan. According to these characteristics, the polymer is considered a necessary compound of the electrochemical insulin sensor, improving the sensor's analytical characteristics

Toxicity of a dental adhesive compared with ionizing radiation and zoledronic acid

Background: To determine the toxicity of aqueous dilutions of a universal self-priming dental adhesive (DA) and comparing these with those elicited by exposure to ionizing radiation (IR), Zoledronic acid (Z) treatment and the synergic effects of the combined treatment with IR+Z. Material and Methods: The genotoxic effect of DA was determined by the increase in the frequency of micronuclei in cytokinesis-blocked in cultured human lymphocytes before and after exposure to 2Gy of X-rays. The cytotoxic effect was studied by using the MTT cell viability test in normal prostate cell lines (PNT2) after exposure to different X-ray doses (0Gy-20Gy). The cell lines divided into different groups and treated with different test substances: DA in presence of O 2 , DA in absence of O 2 , Z-treated and control. Results: An in vitro dose-dependent and time-dependent cytotoxic effect of DA, Z and IR on PNT2 cells ( p >0.001) was demonstrated. DA without-O 2 , following the recommendations of manufacturers, had a more pronounced effect of increasing cell death than DA with-O 2 ( p <0.001). In the genotoxicity assay, DA at 25% of its original concentration significantly increased chromosome damage ( p <0.001). The samples studied were found to be toxic, and the samples photo-polymerized in absence of O 2 showed a bigger cytotoxic effect comparable to the additive toxic effect showed by the combined treatment of IR+Z. Conclusions: Additional effort should be carried out to develop adhesives, which would reduce the release of hazardus substances; since toxic effects are similar to that reported by other agents whose clinical use is controlled by the health authorities

Laser-Induced Periodic Surface Structures on Conjugated Polymers: Poly(3-hexylthiophene)

8 pags.; 11 figs.© 2015 American Chemical Society. In this work, we report on the surface patterning of semiconducting poly(3-hexylthiophene) (P3HT) thin films by means of laser-induced periodic surface structures (LIPSS). Two different laser wavelengths, 266 and 532 nm, and a broad range of fluences and number of pulses have been used in order to optimize the LIPSS morphology. Ripples period and depth can be tuned by laser parameters. In particular, the high optical absorption of P3HT at 532 nm enables the formation of well-ordered nanostructures with periodicities around 460 nm. Near edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopy reveal a good chemical stability of P3HT thin films during LIPSS formation. Conducting atomic force microscopy (C-AFM) performed on the LIPSS reveals a higher electrical conduction in the trenches than in the ridge regions. Resonance Raman spectroscopy and grazing incidence wide-angle X-ray scattering (GIWAXS) indicate a loss of crystallinity of P3HT thin films during LIPSS formation, suggesting melting of the outer polymer surface. This effect produces ridges with molecular order lower than that of the original thin film. As a consequence of this transformation, the electrical conduction in the ridges becomes lower than that in the trenches.The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (MINECO) through Projects MAT 2011-23455, MAT 2012-33517 and CTQ 2013-43086-P. A.R.-R. and E.R. are indebted to MINECO for a FPI (BES-2013-062620) and Ramon y Cajal (RYC-2011-08069) contracts, respectively. We thank the Swiss Light Source for beamtime at PolLux, where the NEXAFS experiments were performed. We also thank the ESRF for beamtime at BM26 where in situ GISAXS and GIWAXS experiments were carried out. We thank B. Watts for assistance in using beamline PolLux and G. Portale and W. Bras for beamline support at BM26. P. Müller-Buschbaum and S. Guo are thanked for seminal comments at the beginning of this workPeer Reviewe

Comment on 'Distinct clinical outcomes of two CIMP-positive colorectal cancer subtypes based on a revised CIMP classification system'

This work was funded by Projects PI13/01741, PI13/01273, PI16/01920 and PI16/01650 from the Spanish Ministry of Health and Consumer Affairs and FEDER, and Mutua Madrileña Foundation (2012-0036), and was approved by the Ethics Committee of our Institution.Peer Reviewe

CardIAP: calcium transients confocal image analysis tool

One of the main topics of cardiovascular research is the study of calcium (Ca2+) handling, as even small changes in Ca2+ concentration can alter cell functionality (Bers, Annu Rev Physiol, 2014, 76, 107–127). Ionic calcium (Ca2+) plays the role of a second messenger in eukaryotic cells, associated with cellular functions such as cell cycle regulation, transport, motility, gene expression, and regulation. The use of fluorometric techniques in isolated cells loaded with Ca2+-sensitive fluorescent probes allows quantitative measurement of dynamic events occurring in living, functioning cells. The Cardiomyocytes Images Analyzer Python (CardIAP) application addresses the need to analyze and retrieve information from confocal microscopy images systematically, accurately, and rapidly. Here we present CardIAP, an open-source tool developed entirely in Python, freely available and useable in an interactive web application. In addition, CardIAP can be used as a standalone Python library and freely installed via PIP, making it easy to integrate into biomedical imaging pipelines. The images that can be generated in the study of the heart have the particularity of requiring both spatial and temporal analysis. CardIAP aims to open the field of cardiomyocytes and intact hearts image processing. The improvement in the extraction of information from the images will allow optimizing the usage of resources and animals. With CardIAP, users can run the analysis to both, the complete image, and portions of it in an easy way, and replicate it on a series of images. This analysis provides users with information on the spatial and temporal changes in calcium releases and characterizes them. The web application also allows users to extract calcium dynamics data in downloadable tables, simplifying the calculation of alternation and discordance indices and their classification. CardIAP aims to provide a tool that could assist biomedical researchers in studying the underlying mechanisms of anomalous calcium release phenomena.Fil: Velez Rueda, Ana Julia. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonano, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Smith, Agustín García. Universidad Nacional de Quilmes; ArgentinaFil: Parisi, Gustavo Daniel. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fornasari, Maria Silvina. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sommese, Leandro Matías. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

In situ monitoring of laser-induced periodic surface structures formation on polymer films by grazing incidence small-angle X-ray scattering

9 pags.; 9 figs.© 2015 American Chemical Society. The formation of laser-induced periodic surface structures (LIPSS) on model spin-coated polymer films has been followed in situ by grazing incidence small-angle X-ray scattering (GISAXS) using synchrotron radiation. The samples were irradiated at different repetition rates ranging from 1 up to 10 Hz by using the fourth harmonic of a Nd:YAG laser (266 nm) with pulses of 8 ns. Simultaneously, GISAXS patterns were acquired during laser irradiation. The variation of both the GISAXS signal with the number of pulses and the LIPSS period with laser irradiation time is revealing key kinetic aspects of the nanostructure formation process. By considering LIPSS as one-dimensional paracrystalline lattice and using a correlation found between the paracrystalline disorder parameter, g, and the number of reflections observed in the GISAXS patterns, the variation of the structural order of LIPSS can be assessed. The role of the laser repetition rate in the nanostructure formation has been clarified. For high pulse repetition rates (i.e., 10 Hz), LIPSS evolve in time to reach the expected period matching the wavelength of the irradiating laser. For lower pulse repetition rates LIPSS formation is less effective, and the period of the ripples never reaches the wavelength value. Results support and provide information on the existence of a feedback mechanism for LIPSS formation in polymer films.The authors gratefully acknowledge financial support from the MINECO (MAT2011-23455, MAT2012-33517 and CTQ 2013-43086-P). E.R., I.M.-F., and A.R-R. also thank MINECO for a Ramon y Cajal contract (RYC-2011-08069) and FPI ́ fellowships (BES-2010-030074 and BES-2013-062620).Peer Reviewe

Implementació i pilotatge de l'entorn virtual d'aprenentatge Quantum LEAP (Learning English for Academic Purposes), com a eina per a la millora de la comunicació acadèmica en anglès a la UPC

Aquest projecte forma part d’un treball més ampli que està duent a terme un equip interuniversitari d'innovació docent, amb seu a la UPC, que treballa en el desenvolupament de Quantum LEAP (Learning English for Academic Purposes, un entorn virtual d'aprenentatge d'anglès acadèmic a la universitat, que contè una gran quantitat i varietat de materials interactius multimèdia pel desenvolupament de la comprensió i expressió oral i escrita en anglès. Amb aquest projecte es dóna resposta a necessitats clau de la universitat actual respecte a les competències de llengua i comunicació (diferents nivells de competència en anglès i diferents estils d’aprenentatge, millorar l’aprenentatge i pràctica de l’anglès acadèmic, per exemple). El context actual està caracteritzat per una major mobilitat acadèmica i profesional, una major presencia de l’anglès com a lingua franca, i una ja plena implantació de l’EEES (Espai Europeu d’Educació Superior) amb èmfasi en els processos d’aprenentatge, l’adquisició de competències i l’aprenentatge autònom. Tenint Institut de Ciències de l’Educació – Universitat Politècnica de Catalunya 2 en compte aquest context i el grau de desenvolupament de Quantum LEAP, en aquest projecte s’ha treballat en la revisió dels materials didàctics, en la implementació de l’entorn d’aprenentatge a l’aula i com a recurs per aprenents autònoms, i s’ha dut a terme una profunda revisió tècnica i de disseny, per tal d’adaptar-lo a criteris pedagògics i d’usabilitat.Peer Reviewe

Rational design of MXene/activated carbon/polyoxometalate triple hybrid electrodes with enhanced capacitance for organic-electrolyte supercapacitors

Altres ajuts: ICN2 and IREC are funded by the CERCA programme / Generalitat de Catalunya, and ICN2. This work has been carried out within the framework of doctoral program (PhD) of Material Science (Department of Physics) of Universitat Autònoma de Barcelona (UAB).We report a triple hybrid electrode (MXene/activated carbon (AC)/polyoxometalates (POMs)) combining the merits of three materials: MXene (high volumetric capacitance), AC (high gravimetric capacitance) and Phosphotungstate (fast redox). Phosphotungstic acid (HPW12) and tetraethylammonium phosphotungstate (TEAPW12) were the two POMs used to prepare MXene/AC/POMs triple hybrids. MXene/AC/TEAPW12 outperformed MXene/AC/HPW12 in 1 M tetraethylammonium tetrafluoroborate (TEABF4)/acetonitrile. Nano-dispersion of POMs facilitates charge storage through surface capacitive processes (91% at 2 mV s). MXene/AC/TEAPW12 delivered significantly higher gravimetric capacitance (87F g at 1 mV s) than MXene (40F g at 1 mV s) in the same organic electrolyte, without sacrificing much volumetric capacitance (less than 10%). The gravimetric capacitance of the triple hybrid was similar to that of MXene/AC, whereas its volumetric capacitance was 1.5 times higher. Replacing TEA cations with 1-ethyl-3-methylimidazolium cations (EMIM), the capacitance improved by 21%. Coupled with AC positive electrodes in an asymmetric cell, MXene/AC/TEAPW12 delivered 4.6 times higher gravimetric energy density and 3.5 times higher volumetric energy density than a similar MXene asymmetric cell at relatively high-power densities. This study proves that MXene/AC/TEAPW12 combines the merits and compensates for the demerits of each component and is a promising electrode material for organic-electrolyte supercapacitors