The evaluation of surface diffusion coefficients of gold and platinum atoms at electrochemical interfaces from combined STM-SEM imaging and electrochemical techniques

A simple method is presented for measuring the surface diffusion coefficients of Au and Pt atoms at electrodispersed electrodes of the same metals in contact with 0.5M H2SO4. The technique is based upon the time dependence of the surface roughness factor of electrodispersed metal overlayers. The method requires a model for the surface roughness of the metal structure. The model is deduced from microscopic measurements by a STM integrated into a conventional SEM microscope. This allows the relationship between the roughness factor and the area of the surface structure to be obtained. For Au and Pt in contact with an electrolyte solution, the values of our diffusion coefficients are higher than those reported in vacuum at the same temperature.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

The evaluation of surface diffusion coefficients of gold and platinum atoms at electrochemical interfaces from combined STM-SEM imaging and electrochemical techniques

A simple method is presented for measuring the surface diffusion coefficients of Au and Pt atoms at electrodispersed electrodes of the same metals in contact with 0.5M H2SO4. The technique is based upon the time dependence of the surface roughness factor of electrodispersed metal overlayers. The method requires a model for the surface roughness of the metal structure. The model is deduced from microscopic measurements by a STM integrated into a conventional SEM microscope. This allows the relationship between the roughness factor and the area of the surface structure to be obtained. For Au and Pt in contact with an electrolyte solution, the values of our diffusion coefficients are higher than those reported in vacuum at the same temperature.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Studies on structural, morphological, and optical properties of Cr2O3 nanoparticles: Synthesized via one step combustion process by different fuels

Esta investigación presenta un nuevo método de síntesis de un solo paso para obtener Cr2O3 nanoestructurado a partir de una solución de nitrato de cromo y un combustible como ácido aspártico, o lisina, o trihidroximetilaminometano, o etilendiaminotetraacético. Una vez obtenido los polvos fueron calcinados a 500ºC. Luego se caracterizaron mediante difracción de rayos X (DRX), microscopía electrónica de barrido (MEB), microscopía electrónica de transmisión (TEM), espectroscopía infrarroja por transformada de Fourier (FTIR), espectroscopía por UV-Visible y técnicas de Brunauer–Emmett–Teller (BET). Estos polvos serán utilizados en superficies absorbedoras como cermts o pinturas selectivas solares. En las cenizas y los polvos calcinados obtenidos se identificó la estructura cristalina del Cr2O3, correspondiente al sistema romboédrico y al grupo espacial R-3c. El tamaño promedio de cristalita de los productos obtenidos estuvo entre 29 y 45 nm, donde para las cenizas el tamaño fue menor en comparación a los polvos obtenidos para todos los combustibles utilizados. Es probable que para un incremento de la temperatura el tamaño de cristalita crezca. Un área específica de 167 m2 /g fue determinada para las cenizas obtenidas con ácido aspártico. Este fue el mayor valor observado en la literatura específica y podría utilizarse para reacciones de catálisis, mientras que el resto de los valores obtenidos para las cenizas fue mayor en comparación a los polvos calcinados para todos los combustibles. El tamaño promedio de partícula observado a través de TEM resultó entre 50 y 100 nm aproximadamente. La energía de Band Gap determinada resultó entre 3.055 eV y 3.078 eV, esta variable aumenta suavemente con la temperatura de calcinación. Para confirmar esta tendencia se deberían realizar mayor cantidad de experimentos.This research presents a novel one-step solution combustion synthesis to obtain nano-structured Cr2O3 from chrome nitrate solution and one fuel such as aspartic acid (Asp) or Lysine (Lys), or trihydroxymethylamino methane (Tris) or ethylenediaminetetraacetic acid (Edta). Once obtained, the ashes were calcined at 500°C. The powders were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy with Fourier transform (FTIR), UV-Visible Spectroscopy (UV-VIS) spectroscopy and Brunauer-Emmett-Teller (BET) techniques. These powders will be used in solar absorbing surfaces: in composites (o cermets) and painted coatings. Within the obtained ashes and calcined powders, it was identified a Cr2O3 crystalline structure corresponding to the rhombohedral system and to the R-3c spatial group. The average crystallite size was determined for ashes and calcined powders, this value was in nanometric range between 29 and 45 nm, where for ashes were in general minor than calcined powders in all cases. It is probable that with an increment of the temperature, crystallite size would grow. A specific area of 167 m2/g was determined for asp-ashes. This was a highest value observed in specific literature and it could be used in catalysis reactions, while the area values of ashes was higher than calcined powders value for each fuel. The average particle size observed through TEM resulted in 50 nm to 100 nm approximately. The determined Energy band gap resulted in 3.055eV to 3.078 eV approximately. The Energy band gap slightly increased with calcination temperature. Further trials and investigation will confirm the mentioned tendencies.Fil: Palermo, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Gardey Merino, María Celeste. Universidad Tecnológica Nacional. Facultad Regional de Mendoza; ArgentinaFil: Vazquez, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Alonso, José A.. Consejo Superior de Investigaciones Científicas; EspañaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Rodriguez, Marina. Universidad Tecnológica Nacional. Facultad Regional de Mendoza; ArgentinaFil: Lassa, Maria Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

A Bethe lattice representation for sandpiles

Avalanches in sandpiles are represented throughout a process of percolation in a Bethe lattice with a feedback mechanism. The results indicate that the frequency spectrum and probability distribution of avalanches resemble more to experimental results than other models using cellular automata simulations. Apparent discrepancies between experiments are reconciled. Critical behavior is here expressed troughout the critical properties of percolation phenomena.Comment: 5 pages, 4 figures, submitted for publicatio

Supergravity brane worlds and tachyon potentials

We study massless and massive graviton modes that bind on thick branes which are supergravity domain walls solutions in $D$-dimensional supergravity theories where only the supergravity multiplet and the scalar supermultiplet are turned on. The domain walls are bulk solutions provided by tachyon potentials. Such domain walls are regarded as BPS branes of one lower dimension that are formed due to tachyon potentials on a non-BPS D-brane.Comment: RevTex4, 6 pages; version to appear in Phys. Rev.

Plio-Quaternary tectonic evolution of the southern margin of the Alboran Basin (Western Mediterranean)

We thank the members of the SARAS and Marlboro cruises in 2011 and 2012. We thank Emanuele Lodolo, Jacques Déverchère, Guillermo Booth-Rea for their helpful comments and discussion. We also thank the editor, Federico Rossetti, for the attention provided to this article. This work was funded by the French program Actions Marges, the EUROFLEETS program (FP7/2007-2013; no. 228344) and project FICTS-2011-03-01. The French program ANR-17-CE03-0004 also supported this work. Seismic reflection data were processed using the Seismic UNIX SU and Geovecteur software. The processed seismic data were interpreted using Kingdom IHS Suite© software. This work also benefited from the Fauces Project (Ref CTM2015-65461-C2-R; MINCIU/FEDER) financed by Ministerio de Economía y Competitividad y al Fondo Europeo de Desarrollo Regiona (FEDER).Progress in the understanding and dating of the sedimentary record of the Alboran Basin allows us to propose a model of its tectonic evolution since the Pliocene. After a period of extension, the Alboran Basin underwent a progressive tectonic inversion starting around 9–7.5 Ma. The Alboran Ridge is a NE–SW transpressive structure accommodating the shortening in the basin. We mapped its southwestern termination, a Pliocene rhombic structure exhibiting series of folds and thrusts. The active Al-Idrissi Fault zone (AIF) is a Pleistocene strike-slip structure trending NNE– SSW. The AIF crosses the Alboran Ridge and connects to the transtensive Nekor Basin and the Nekor Fault to the south. In the Moroccan shelf and at the edge of a submerged volcano we dated the inception of the local subsidence at 1.81– 1.12 Ma. The subsidence marks the propagation of the AIF toward the Nekor Basin. Pliocene thrusts and folds and Quaternary transtension appear at first sight to act at different tectonic periods but reflect the long-term evolution of a transpressive system. Despite the constant direction of Africa– Eurasia convergence since 6 Ma, along the southern margin of the Alboran Basin, the Pliocene–Quaternary compression evolves from transpressive to transtensive along the AIF and the Nekor Basin. This system reflects the logical evolution of the deformation of the Alboran Basin under the indentation of the African lithosphere.This research has been supported by the CNRSINSU-TOTAL-BRGM-IFREMER Actions Marges program, EUROFLEETS program FP7/2007-2013 (grant no. 228344), EU Regional Structural Fund (grant no. FICTS-2011-03-01) and DAMAGE Project (project no. FEDER/CGL2016-80687-R AEI), Fauces Project (project no. FEDER/CTM2015-65461-C2-R; MINCI), ALBAMAR Project (project no. ANR/ANR-17-CE03-0004)

The evaluation of surface diffusion coefficients of gold and platinum atoms at electrochemical interfaces from combined STM-SEM imaging and electrochemical techniques

A simple method is presented for measuring the surface diffusion coefficients of Au and Pt atoms at electrodispersed electrodes of the same metals in contact with 0.5M H2SO4. The technique is based upon the time dependence of the surface roughness factor of electrodispersed metal overlayers. The method requires a model for the surface roughness of the metal structure. The model is deduced from microscopic measurements by a STM integrated into a conventional SEM microscope. This allows the relationship between the roughness factor and the area of the surface structure to be obtained. For Au and Pt in contact with an electrolyte solution, the values of our diffusion coefficients are higher than those reported in vacuum at the same temperature.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Popliteal block with transfibular approach in ankle arthrodesis: a case series

<p>Abstract</p> <p>Introduction</p> <p>Ankle arthrodesis is primarily undertaken to control severe pain in the ankle joint. Immediate postoperative pain is usually treated using oral analgesics, intravenous opiates and regional anaesthesia. The outcomes of ankle fusion, including patient satisfaction studies, are well documented in the literature. However, the advantage of popliteal block in the management of early postoperative pain after ankle fusion for osteoarthritis has not been widely reported. This study aims to determine the role of popliteal block using ankle fusion in the management of ankle osteoarthritis.</p> <p>Case presentation</p> <p>Ankle arthrodeses were performed in 27 patients over a five-year period. Eighteen patients were males (one had bilateral arthrodesis) and eight were females. Their mean age was 56 years and they were all Caucasians. The notes and radiographs of the patients were reviewed in retrospect for the duration of their hospital admission, time to union and complications.</p> <p>Conclusion</p> <p>Popliteal block is a safe and effective technique for postoperative analgesia in ankle arthrodesis. By using this technique, we achieved a significant reduction in the duration of hospital stay for our patients after ankle arthrodesis. The resultant cost saving was GBP717 for each patient.</p

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients' PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa