Comparison of three molecular subtyping techniques for Listeria monocytogenes Comparación de tres técnicas para subtipificación molecular de Listeria monocytogenes Londero, Alejandra; Costa, Magdalena; Sucari, Adriana; Leotta, Gerardo Anibal Listeria monocytogenes is a foodborne pathogen. The recent alert for L. monocytogenes in vegetables from Argentina warns about the importance of reinforcing its isolation, characterization and subtyping in food, clinical and environmental samples. The aim of the present study was to compare the discriminatory power of enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), automated ribotyping and pulsed-field gel electrophoresis (PFGE) to subtype strains of L. monocytogenes isolated from Argentine meat and environmental samples. Simpson's Diversity Index (DI) was calculated on the basis of based on the dendrograms obtained in the by cluster analysis, showing the following discriminatory power: ApaI-PFGE (0.980), AscI-PFGE (0.966), ribotyping (0.912), ERIC-PCR (0.886). The ID values between ApaI- and AscI-PFGE and between ribotyping and ERIC-PCR were not significantly different. Of the three techniques evaluated, PFGE showed the highest discriminatory power. However, the subtyping techniques should be accompanied by effective food monitoring strategies and reliable clinical and epidemiological studies.

Counter-complementarity control of the weak exchange interaction in a bent {Ni(ii)3 complex with a μ-phenoxide-μ-carboxylate double bridge Fiorini, Guillermo; Carrella, Luca; Rentschler, Eva; Alborés, Pablo We have prepared and structurally characterized a novel {Ni3} bent complex bearing a double μ-phenoxide-μ-carboxylate bridge. Both terminal Ni(ii) sites are symmetry related, offering a simplified exchange interaction scheme. DC magnetic data is consistent with a weak antiferromagnetic interaction between the central and terminal Ni(ii) ions. As expected for a Ni(ii) system, local zero-field splitting is observed, which can be experimentally established. Broken symmetry quantum chemical calculations, as well as ab initio CASSCF-SA-SOC computations that support the magnetic experimental data, were also performed. From the analysis of other reported closely related Ni(ii) systems, a counter-complementarity effect exerted by the carboxylate bridge is proposed, which might explain the weaker exchange interactions compared to those observed in double μ-phenoxide bridged Ni(ii) compounds.

Impact of permeabilization and pH effects in the electrochemical treatment of tumors: Experiments and simulations Maine Calzado, Enaide; Schinca, Herman; Bergues Cabrales, Luis Enrique; García, F.M.; Turjanski, Pablo Guillermo; Olaiz, Nahuel Manuel Electrochemical treatment is used in the local control of solid tumors in preclinical and clinical studies. We study pH fronts, permeabilization, electrical field and concentration of four chemical species in a tissue under electrochemical treatment by means of in vitro and in silico modeling. The in vitro model uses a piece of potato (solanum tuberosum L.) as analogy of tumor tissue, due to the characteristics of the potato tissue and the way in which it reacts against pH and potential. The in silico model solves the two-dimensional Nernst-Planck equations for ionic transport in a four-ion electrolyte. Modeled ions demonstrate the diffusive regime of ionic transport and show the little influence of the low electric field applied on this phenomenon. This work evidences that extreme pH fronts affect the permeabilization of the tissue and consequently its destruction. We also evaluate different shapes of electrode arrays by means of simulated and in vitro models. We concluded that the higher area of necrotic tissue was achieved for the greater separation between electrodes.

First characterization of a canine parvovirus causing fatal disease in coatis (Nasua nasua) Bucafusco, Danilo; Argibay, Hernán Darío; Diaz, Leandro; Vega, Celina Guadalupe; Minatel, Leonardo; Postma, Gabriela; Rinas, Miguel; Bratanich, Ana Cristina A canine parvovirus (CPV)-like virus was detected by PCR and isolated from dead coatis in Argentina. Analysis of the full-length genome sequence revealed that it resembled CPV-but also contained a mutation in the VP2 protein (Arg377Ser) that has not been described previously. This is the first report of a CPV-like virus producing clinical disease in coatis. Genetic similarity to CPV-2c viruses detected in Brazil suggests a strong relationship between these viruses. Although the pathogenic potential of CPV- and feline panleukopenia virus (FPV)-like strains in wild animals is still not completely understood, this study highlights the importance of parvoviruses as a threat to wildlife if proper conditions are present.

Inhibitory Processes Training for School-age Children: Transfer Effects Aydmune, Yésica; Introzzi, Isabel Maria; Lipina, Sebastián Javier Inhibition refers to a basic executive component that can be conceptualized as consisted of different inhibitory processes (i.e., perceptual, cognitive and response inhibition). These processes emerge during the first years of life, and since then are involved in different relevant every day activities. Different individual and contextual factors can modulate their developmental trajectories. The possibility of train in separate ways each inhibitory process is a subject of analysis. In such a context, the aims of this work were: (a) to design, implement and evaluate training of perceptual, cognitive and response inhibition processes, in a sample of school-aged children (6 to 8 years old); and (b) to analyze near, far, short- and long-transfer effects. An experimental design with three training groups (one for each inhibitory process) and an active control group was implemented. Near transfer effects were not observed. We found effects on a visuospatial working memory task in the short term, after the training in the response and cognitive inhibition, and effects on a fluid intelligence task in both the short and long term after the training in cognitive inhibition. The results contribute to a conceptualization of multidimensional inhibitory processes and the plausibility of training them during childhood.

La suspensión estoica del sentido de justicia: Estrategias y dificultades; The Stoic suspension of the sense of justice: Strategies and difficulties Braicovich, Rodrigo Sebastián El objetivo del artículo consistirá en analizar las distintas estrategias que encontramos en las fuentes del estoicismo imperial destinadas a poner en suspenso nuestro sentido de justicia, el cual es considerado implícitamente por los estoicos del período como responsable de algunas actitudes no deseables en nuestra búsqueda de la eudaimonía. Organizaré las estrategias de acuerdo a dos grandes grupos: aquellas que atacan la idea de que una injusticia ha sido cometida, y aquellas que apuntan a la idea de que, aun cuando una injusticia haya sido cometida, existen actitudes más convenientes para exhibir ante la misma que la demanda de castigo o el deseo de venganza. Finalizaré enfatizando la dificultad de conciliar los dos conjuntos de estrategias y sugeriré una posible forma de explicar las razones de dicha dificultad.; The aim of the paper will be to analyze the different strategies that the Stoics of the Imperial times designed in order to put our sense of justice on hold, due to the fact that it is deemed responsible for certain attitudes which do not contribute to our search for eudaimonía. I will organize such strategies in two groups: the first one corresponds to the strategies that target the idea that an injustice has been committed; the second one corresponds to the ones that aim to show that there are more convenient attitudes towards injustice than the demand for punishment or the desire for revenge. I will end by pointing at the difficulty of reconciling both sets of strategies, and I will suggest a possible way to account for that difficulty.

Los adolescentes de la zona oeste: Construcción de identidades y producción de subjetividad; Teenagers from the west: Identities construction and subjetivities production Pagnoni, Anahí Guadalupe; Bais, Paulina Antonela El siguiente escrito tiene como objetivo dar a conocer el trabajo realizado en el proyecto de extensión: “Problemáticas en torno a las identidades y los derechos en los/las jóvenes de barrios vulnerados de la ciudad”, durante 2016 y 2017 en la ciudad de Rosario. Surge a partir de los registros escritos y visuales de los coordinadores al finalizar la experiencia. Nos interesamos, por un lado, en conocer la forma de relación e integración de los adolescentes con el barrio y los diferentes espacios que lo constituyen. Por otro lado, en explorar las formas de producción de subjetividades y la construcción de identidades de las adolescencias de la zona oeste de la ciudad. Priorizando su forma de ver, estar, pensar y percibir el mundo. Esta experiencia apostó a la construcción colectiva de conocimientos, entendiendo esta como una práctica implicada. En ella son puestas en juego nuestras inquietudes y el modo en que estas son interpeladas, siendo este un posicionamiento político y ético. Este proyecto fue desarrollado por estudiantes, graduados y docentes de las carreras de Ciencia Política, Historia y Psicología, sumándose a participar estudiantes de periodismo y nutrición referentes del barrio, así como también colaboradores miembros del club. Esta multiplicidad de campos participantes permitió, no sólo un enriquecimiento mutuo en cada experiencia compartida, sino también afianzar los vínculos entre la universidad y los barrios de la ciudad. Siendo la universidad parte de la comunidad, tiene como deber fomentar las relaciones de ésta con la sociedad.; This text was written with the goal to make public the work done in the extension project called: “Troubles about the identities and the rights of young people from shanty towns”, during 2016 and 2017 in Rosario. This project comes from the written and visual records of the coordinators when they finished the experience. At first, we were interested on understand the relationship ante teenager´s way of integration with the town, and different spaces that from it. In the other hand, we were interested on explore the patters of production of subjectivities and the construction of teenager´s identities from west zone of the city. Giving priority to their point of view, their way to be, they way of thinking, and how perceive the word. This experience bets on the collective building of knowledges, and it is understood as an involved practice, in which is put at stake our concerns and the way to interpellate them. Therefore it is an ethical and political position. The present project was developed by students, graduates and teachers from politics sciences, history and psychology career. Were added journalism and nutrition students town´s mentors, helpers and members of the club. Those multiple fields gave us not only a mutual improvement with each shared experience, but also strengthen links between the university and the towns of the city. Being the last mentioned part of the community; it should promote the relationship between itself and the society.

Un análisis de las empresas TIC desde una perspectiva financiera: Evidencia para las pymes de software y videojuegos; Analysis of ICT companies from a financial perspective: evidence for software and video games SMEs; Análise das empresas TIC sob uma perspectiva financeira: Evidência para as PMEs de software e videogames Guercio, María Belén; Martinez, Lisana Belén; Vigier, Hernan Pedro El objetivo de este trabajo es evaluar las decisiones de financiamiento de dos sub­sectores específicos del segmento de tecnologías de la información y la comunicación (TIC): el de desarrollo de videojuegos (VG) y el de software y servicios informáticos (SSI). Los datos utilizados incluyen 80 empresas argentinas relevadas durante el 2017. Los resultados muestran que la fuente principal de financiamiento en las diferentes etapas del ciclo de negocio son los fondos propios para todas las empresas de la muestra. Sin embargo, la participación de dichos fondos se reduce a medida que las empresas transitan las etapas de start up y de crecimiento. Además, se encuentra que la tipología de las fuentes externas con las que sustituyen el financiamiento propio difiere de acuerdo con el subsector analizado. En la etapa de start up, las empresas de SSI sustituyen fondos propios por subsidios públicos, a diferencia de las empresas de VG que utilizan el financiamiento de prestamistas privados. En la etapa de crecimiento, las empresas de SSI utilizan en mayor proporción financiamiento bancario, y las empresas de VG, subsidios públicos.; This work seeks to evaluate the financing decisions of two specific subsectors of the information and communication technologies (ICT) segment: video games development (VG) and software and computer services (SCS). The data used includes 80 Argentinian companies surveyed during 2017. Results show that the main financing source at the different stages of the business cycle is the company’s own funds for all the busi­nesses in the sample. However, the participation of these funds is reduced as companies go through the start-up and growth stages. In addition, it is found that the typology of external sources with which they replace their own financing differs according to the subsector. In the start-up stage, SCS companies substitute their own funds for public subsidies, unlike VG companies, which use financing from private lenders. In the growth stage, SCS companies use bank financing to a greater extent, while VG companies request public subsidies.; O objetivo deste trabalho é avaliar as decisões de financiamento de dois subsetores específicos do setor de tecnologias da informação e da comunicação (TIC): o desenvolvimento de videogames e o de software e ser­viços informáticos (SSI). Os dados utilizados incluem 80 empresas argen­tinas e foram levantados durante 2017. Os resultados mostram que a fonte principal de financiamento nas diferentes etapas do ciclo de negócio são os fundos próprios para todas as empresas da amostra. Contudo, a parti­cipação desses fundos é reduzida à medida que as empresas passam pelas etapas de start up e de crescimento. Além disso, verifica-se que a tipologia das fontes externas com as quais substituem o financiamento próprio di­fere de acordo com o subsetor analisado. Na etapa de start up, as empresas de ssi substituem fundos próprios por incentivos públicos, à diferença das empresas de videogames que utilizam o financiamento de organismos de crédito privados. Na etapa de crescimento, as empresas de ssi utilizam, em maior proporção, financiamento bancário, e as empresas de videogames, in­centivos públicos.

La Iniciativa Ciudadana de Referéndum: lineamientos para su reforma Linares, Sebastián; Welp, Yanina La iniciativa ciudadana de referéndum (ICR) permite a la ciudadanía someter a votación popular un proyecto de ley, la validación o veto de una ley sancionada por el Congreso (o un decreto del Ejecutivo), o un proyecto de reforma constitucional. En un escenario de creciente desencanto ciudadano con la capacidad transformadora de la política y con los políticos, las ICR están especialmente preparadas para ofrecer canales de refuerzo en ambas direcciones: poniendo limitaciones al poder y dando herramientas a la ciudadanía para intervenir en la toma de decisiones. Y, en principio, su regulación se ha expandido en los países de América Latina. Sin embargo, su desempeño es muy pobre y dista de derivar en los resultados esperados. Partiendo de esta evidencia este documento identifica las reformas necesarias para que las ICR no sean letra muerta.

A putative novel strain of Ehrlichia infecting Amblyomma tigrinum associated with Pampas fox (Lycalopex gymnocercus) in Esteros del Iberá ecoregion, Argentina Eberhardt, María Ayelen Teresita; Fernández, Camilo; Fargnoli, Lucía; Beldomenico, Pablo Martín; Monje, Lucas Daniel The current work evaluated road-killed Pampas foxes (Lycalopex gymnocercus) and their ticks for the presence of vector-borne agents in the ecoregion Esteros del Iberá in northeastern Argentina. Spleen, lung and blood samples and Amblyomma tigrinum adult ticks collected from the foxes were tested by polymerase chain reaction (PCR) assays targeting bacteria of the genera Ehrlichia, Anaplasma, and Rickettsia. All foxes tested were negative for the three genera, but evidence of Ehrlichia and Rickettsia infection was detected in the ticks. One A. tigrinum (out of 12 tested) was infected by an ehrlichial agent, here named Ehrlichia sp. strain Iberá, related to ehrlichial agents recently detected in platypuses in Tasmania (Ornithorhynchus anatinus) and in voles (Myodes rutilus and Myodes rufocanus) and shrews (Sorex araneus) in the Russian Far East. Regarding Rickettsia, all A. tigrinum ticks (100%) were infected by ´Candidatus Rickettsia andeanae´, a member of the spotted fever group rickettsia of unknown pathogenicity. Further research is necessary to unveil the ecology of Ehrlichia sp. strain Iberá as well as its zoonotic relevance. The species of the genus Ehrlichia are known to be pathogenic to mammals, including humans and domestic animals, thus the presence of this ehrlichial agent in A. tigrinum is a potential risk for veterinary and public health, as the adults of A. tigrinum are common parasites of dogs in rural and peri-urban environments, and humans are also frequently bitten by this tick species.

Improved Electrochemical Performance of NCM Cathode Materials Based on the Modification of the Salt Content in the Electrolyte Ortiz, Mariela Gisela; Čech, O.; Sedlaríková, M. In this work, NCM cathode materials, for Li-ion batteries, weresynthesized via a solid-state reaction routine, in which manganese(IV) dioxide, nickel (II) oxide, cobalt (II) hydroxide and lithiumhydroxide monohydrate were employed as metal precursors withdifferent calcination temperature. The prepared materials wereused as a cathode material for lithium-ion batteries and theelectrochemical performance was studied by galvanostatic chargedischargecycling, cyclic voltammetry, electrochemical impedancespectroscopy and rate capability, in which as electrolyte, 1M and1.5M LiPF6 in a mixture of ethylene carbonate and dimethylcarbonate (EC:DMC- 1:1 w/w and 1:2 w/w, respectively) wereemployed.

NIR- and thermo-responsive semi-interpenetrated polypyrrole nanogels for imaging guided combinational photothermal and chemotherapy Theune, Loryn E.; Buchmann, Jens; Wedepohl, Stefanie; Molina, María Alejandra; Laufer, Jan; Calderón, Marcelo Versatile, multifunctional nanomaterials for theranostic approaches in cancer treatment are highly on demand in order to increase therapeutic outcomes. Here, we developed thermo-responsive nanogels equipped with the efficient near-infrared (NIR) transducing polymer polypyrrole (PPY) for combinational photothermal and chemotherapeutic therapy along with photoacoustic imaging ability. Long-term stability and water-dispersibility of PPY was achieved using semi-interpenetration method for in situ polymerization of PPY into hydrophilic thermo-responsive nanogels. The semi-interpenetrated nanogels of spherical shape and with hydrodynamic sizes of around 200 nm retained the temperature response behaviour and exhibit excellent photothermal transducing abilities in the NIR region. The PPY nanogels served as photoacoustic contrast agents, which allowed determination of biodistribution profiles ex vivo. In addition, we developed a new method for biodistribution determination based on the photothermal response of the nanogels with an accuracy down to 12.5 μg/mL. We examined the ability of the nanogels as photothermal agents and drug delivery systems in vitro and in vivo. We showed that they efficiently inhibit tumor growth with combinational effects of chemotherapeutics and photothermal treatment. Our work encourages further exploration of nanogels as functional stabilizing matrix for photothermal transducers and their application as drug delivery devices in combination with photothermal therapy and imaging.

Insight into the Mechanism of Oxygen Reduction Reaction on Micro/Mesoporous Carbons: Ultramicropores versus Nitrogen-Containing Catalytic Centers in Ordered Pore Structure Barrera Diaz, Deicy Amparo; Florent, Marc; Sapag, Manuel Karim; Bandosz, Teresa J. Ordered mesoporous/microporous carbon was synthesized from sucrose. The carbon was oxidized and modified with urea at 600, 800, and 950 °C. The obtained carbons differed in the pore size distributions in the meso- and micropore ranges. The carbons, after an extensive surface characterization, were used as ORR catalysts in a KOH electrolyte. Kinetic current densities and n reached 12.5 mA cm-2 and 3.94, respectively. The results suggested that small micropores increased the efficiency of ORR. The density of surface oxygen in mesopores had also a positive effect on ORR by increasing the hydrophilicity and the electrochemically active surface area (ECSA) and, thus, the accessibility of oxygen dissolved in the electrolyte to the pores of the highest adsorption potential. From the viewpoint of the number of electron transfers, current density, and onset potential, the carbons with small pore sizes and with only traces of nitrogen performed equally, or even better, in ORR process as those containing the catalytic nitrogen sites.

Interaction between β‑Lactoglobuline and Weak Polyelectrolyte Chains: A Study Using Monte Carlo Simulation Torres, Paola Beatriz; Quiroga, Evelina; Ramirez Pastor, Antonio Jose; Boeris, Valeria; Narambuena, Claudio Fabian Complexation between the β-lactoglobulin and a weak acid polyelectrolyte (PE) has been studied using Monte Carlo simulations. Different coarse-grained models were used to represent the system, and two different acidic constants were used on the PE model. The protein-PE interaction is quantified considering the average PE monomers adsorbed on the protein as a function of pH. A maximum in the interaction between macromolecules was found, which is explained as a function of the titration behavior of the β-lactoglobuline and weak PE. We also found that there was a direct relation between the pH range of monomers adsorbed and the change on dissociation profile of the protein and weak PE compared to isolated conditions. The complexation of protein-PE increased both the dissociation degree of the PE chain and the protein net charge. This benefits the monomer adsorption on the protein surface.

Optimization of RANS turbulence models using genetic algorithms to improve the prediction of wind pressure coefficients on low-rise buildings Gimenez, Juan Marcelo; Bre, Facundo Being associated with natural ventilation, the pressure distribution on surfaces is relevant for energy consumption, thermal comfort, and air quality in buildings. The aim of this work is to present a simulation-based optimization methodology to recalibrate the closure coefficients of Reynolds-averaged Navier-Stokes (RANS) turbulence models in order to improve the prediction of wind surface-averaged pressure coefficients on a wide range of isolated low-rise buildings. To accomplish this, genetic algorithms and Computational Fluid Dynamics (CFD) simulations are dynamically coupled to find the closure coefficients set which minimize the CFD prediction error regarding wind-tunnel experimental data. The methodology is applied to two turbulence models, the renormalization group k-epsilon model (RNG) and the Spalart-Allmaras model (SA), considering as target cases buildings with different roof types (flat, gable and hip) and wind incidence angles. In order to show the strength of the novel optimal sets of closure coefficients obtained, an exhaustive validation is performed over other low-rise buildings (52 new cases) which were not calibrated against. Results validate using the optimal sets because the recalibrated RNG and SA models decrease the prediction error between 11-64% and 8?45%, respectively, regarding using the standard ones.

Los conciertos del Centenario: Nacionalismo, música y distinción en el aniversario de la fundación de Bahía Blanca (1928); The concerts of the Centenary: Nationalism, music and distinction on the annuversary of the foundation of Bahia Blanca Caubet, María Noelia El presente artículo indaga en la programación musical de los conciertos organizados por la Comisión Oficial del Centenario con motivo del aniversario de fundación de Bahía Blanca en 1928. Este acontecimiento constituyó un momento consagratorio de balance y exhibición de los progresos de la ciudad en el que la música ocupó un rol destacado. En este marco fue estrenado el Himno a Bahía Blanca, escrito por Carlos Alberto Leumann y musicalizado por Pascual de Rogatis, cuya interpretación estuvo a cargo de un coro y una orquesta integrados por músicos locales. Asimismo, actuaron en sucesivas funciones los cuerpos estables del Teatro Colón de Buenos Aires. Sostenemos que los conciertos del centenario procuraron intervenir en la construcción de la identidad nacional pero también se propusieron consolidar las diferencias entre las élites y los sectores populares. Desde una perspectiva que se inscribe en la Historia Cultural pero que incorpora herramientas teóricas de la Sociología, la Microhistoria y la Musicología, pretendemos demostrar las potencialidades que tiene la programación para analizar los nexos entre la música y la sociedad local, así como las tensiones presentes en las selecciones de los repertorios.; The present article attempts to inquire into the musical programming of several concerts organized by the official Commission of the Centennial on the occasion of the 1928’s Bahía Blanca’s foundation anniversary. This event constituted a consecration of the progress in the city where the Arts and music in particular, played a prominent role. It was in this context that the Himno a Bahía Blanca [Bahía Blanca’s anthem] was released, written by Carlos Alberto Leumann and musicalized by Pascual De Rogatis. The performance was in charge of a choir and an orchestra integrated by local musicians. In addition, the stable bodies of the Colon Theater of Buenos Aires performed in successive presentations. We maintain that these centenary concerts sought to intervene in the construction of national identity but also attempted to consolidate the differences between cultural elites and popular sectors. From a perspective that is inscribed in Cultural History but incorporates theoretical tools of Sociology, Microhistory and Musicology, we intend to demonstrate the potential of those programming to analyze the links between music and local society, as well as the tensions inherent to the selection of the repertoires.

Bioactive compounds obtained from Oilseed by-products with subcritical fluids: Effects on Fusarium verticillioides growth Bodoira, Romina Mariana; Velez, Alexis; Maestri, Damian; Herrera, Jimena María Recovery of bioactive compounds from wastes is gaining interest because they could add value  to by-products arising from, for example, the oil extraction processes. In this work, green solvent extraction (water/ethanol under sub-critical conditions) was used to obtain bioactive compounds from peanut, sesame and pistachio agro-industrial by-products. Extracts were analyzed in their overall chemical composition and tested on growth, ergosterol and fumonisin FB1 production by Fusarium verticillioides. The effects of the extracts on fungal growth rate and biochemical markers were not univocal, and could be associated to differences in their chemical profiles.  Extracts obtained from peanut skin - composed mainly by monomeric and dimeric flavonoids - caused significant reductions in fungal growth rate but increased FB1 production. Extracts from  sesame seeds - dominated by furofuran-type lignans - did not have a clear inhibitory effect on  growth rate but strongly reduced both FB1 and ergosterol production. Extracts from pistachio  nuts - characterized by monomeric flavonoids and gallic acid derivatives ? showed minor effects  on both fungal growth rate and biochemical markers. Sub-critical fluid extraction of peanut skin  and defatted sesame seeds may provide an efficient method to obtain extracts rich in phenolic and lignan compounds with potential use as antifungal agents.

Molecular Anchoring to Oxide Surfaces in Ultrahigh Vacuum and in Aqueous Electrolytes: Phosphonic Acids on Atomically-Defined Cobalt Oxide Bertram, Manon; Schuschke, Christian; Waidhas, Fabian; Schwarz, Matthias; Hohner, Chantal; Montero, María de Los Angeles; Brummel, Olaf; Libuda, Joerg In this work, we investigated the interaction of phenylphosphonic acid (PPA, C6H5PO3H2) with atomically-defined Co3O4(111) thin films, grown on Ir(100), under ultrahigh vacuum (UHV) conditions and in the electrochemical environment. In the first step, we employed infrared reflection absorption spectroscopy (IRAS) and followed the formation of a saturated monolayer (380 K) in UHV. We observed that the binding motif changes from a chelating tridentate in thesub-monolayer regime to a chelating bidentate at full monolayer coverages. In the electrochemical environment, we analyzed the interaction of PPA with the same Co3O4(111) surface by electrochemical infrared reflection absorption spectroscopy (EC-IRRAS) (0.3 VRHE ? 1.3 VRHE). When adsorbed at pH 10 from an ammonia buffered aqueous solution, PPA binds to the surface in form of a fully deprotonated chelating bidentate. With increasing electrode potential, we observed two fully reversible processes. At low buffer concentration, protons are released upon oxidation of surface Co2+ ions and lead to protonation of the anchored phosphonates. At high buffer concentration, most of the protons released are accepted by NH3. Simultaneously, the surface phosphonate changes its adsorption motif from bidentate to tridentate while adopting a more upright geometry.

Compact and efficient gas diffusion electrodes based on nanoporous alumina membranes for microfuel cells and gas sensors Fernandez, Jose Luis; Tosello, Rocío T.; Fernandez, Jose Luis This work describes the fabrication, characterization and evaluation of thin gas diffusion electrodes (GDEs) that are capable of electrocatalyzing the reaction of dissolved gases operating at high diffusion limiting current densities and with fast response times. Nanoporous alumina membranes (NAMs) were used as supports of metal electrocatalysts. NAMs were hydrophobized by silanization and coated on one side with Pt, either over the whole alumina surface by sputtering or just onto the pore openings by local chemical deposition. The Pt-modified NAM-based GDEs were evaluated for hydrogen oxidation. They operated by exposing their coated side to the electrolyte solution and the hydrophobic uncoated side to the flowing gas. Due to the NAM hydrophobicity, flooding of the pores by the electrolyte was diminished, so they were quickly filled by the circulating gas. Simulations of the process on single-pore GDEs showed that the dissolved gas diffused into the solution both radially (ideal pore) and linearly ( partially flooded pore), reaching the electrocatalyst film placed right around the pore, which guaranteed a fast mass transport. Hydrogen oxidation operated on these NAM-based GDEs at a steady state with limiting current densities as high as 0.5 A cm−2, which were attained in less than 5 s and were proportional to H2 concentrations over a wide range. Thus, their potential use in microfuel cells and gas sensors was demonstrated.

Lysophosphatidic acid induces the crosstalk between the endovascular human trophoblast and endothelial cells in vitro Beltrame, Jimena Soledad; Scotti, Leopoldina; Sordelli, Micaela Soledad; Cañumil, Vanesa Alejandra; Franchi, Ana Maria; Parborell, Maria Fernanda Agustina; Ribeiro, Maria Laura Spiral artery remodeling at the maternal?fetal interface is crucial for successful pregnancy and requires the interaction between the first trimester trophoblast and the endothelial cells of the maternal vessels. However, the precise mechanism of this dialog has yet to be determined. The current study investigated whether lysophosphatidic acid (LPA) modulates trophoblast?endothelial crosstalk in vitro. HTR-8/SVneo trophoblast cell line (H8) was seeded on top of Geltrex, incubated with LPA or LPA + NS-398 (selective cyclooxygenase-2 inhibitor), LPA + 1400W (selective inducible nitric oxide synthase inhibitor) or LPA + IL-6 neutralizing antibody and assayed for tube formation to model the acquisition of trophoblast endovascular phenotype. The supernatants were collected and used as conditioned media (CM). To test trophoblast?endothelial crosstalk, the endothelial cell line EA.hy926 was incubated with trophoblast CM. The CM from LPA-induced tubulogenesis stimulated endothelial cells migration and did not modify the apoptosis. Soluble factors derived from cyclooxygenase-2 and IL-6 pathways were involved in H8?EA.hy926 interaction under the LPA effect. Moreover, LPA increased the levels of IL-6 mRNA by cyclooxygenase-2 pathway in H8 cells. Collectively, LPA promotes trophoblast?endothelial crosstalk in vitro and induces the release of trophoblast soluble factors that stimulate endothelial cells migration without changes in apoptosis. The evidence presented here provides new insights about an active role of LPA as a lipid mediator regulating vascular remodeling at the maternal?fetal interface.