Revealing the Intercalation Mechanism of Aluminum Fluoride in Graphite

The electrolyte intercalation mechanism facilitates the insertion/extraction of charge into the electrode material in rechargeable batteries. Aluminum fluoride (AlF$_{3}$) has been used as an electrolyte in rechargeable aluminum batteries with graphite electrodes, demonstrating improved reversibility of battery charging and discharging processes; however, the intercalation mechanism of this neutral molecule in graphite is so far unknown. In this work, we combine scanning tunneling microscopy (STM) in ultra-high vacuum conditions, calculations based on density functional theory, and large-scale molecular dynamics simulations to reveal the mechanism of AlF$_{3}$ intercalation in highly oriented pyrolytic graphite (HOPG). We report the formation of AlF$_{3}$ molecules clusters between graphite layers, their self-assembly by graphene buckling-mediated interactions, and explain the origin and distribution of superficial {\it blisters} in the material.Comment: 8 pages, 3 figures, SI on deman

Evidence of strong antiferromagnetic coupling between localized and itinerant electrons in ferromagnetic Sr2FeMoO6

Magnetic dc susceptibility ($\chi$) and electron spin resonance (ESR) measurements in the paramagnetic regime, are presented. We found a Curie-Weiss (CW) behavior for $\chi$(T) with a ferromagnetic $\Theta = 446(5)$ K and $\mu_{eff} = 4.72(9) \mu_{B}/f.u.$, this being lower than that expected for either $Fe^{3+}(5.9\mu_{B})$ or $Fe^{2+}(4.9\mu_{B})$ ions. The ESR g-factor $g = 2.01(2)$, is associated with $Fe^{3+}$. We obtained an excellent description of the experiments in terms of two interacting sublattices: the localized $Fe^{3+}$ ($3d^{5}$) cores and the delocalized electrons. The coupled equations were solved in a mean-field approximation, assuming for the itinerant electrons a bare susceptibility independent on $T$. We obtained $\chi_{e}^{0} = 3.7$ $10^{-4}$ emu/mol. We show that the reduction of $\mu_{eff}$ for $Fe^{3+}$ arises from the strong antiferromagnetic (AFM) interaction between the two sublattices. At variance with classical ferrimagnets, we found that $\Theta$ is ferromagnetic. Within the same model, we show that the ESR spectrum can be described by Bloch-Hasegawa type equations. Bottleneck is evidenced by the absence of a $g$-shift. Surprisingly, as observed in CMR manganites, no narrowing effects of the ESR linewidth is detected in spite of the presence of the strong magnetic coupling. These results provide evidence that the magnetic order in $Sr_{2}FeMoO_{6}$ does not originates in superexchange interactions, but from a novel mechanism recently proposed for double perovskites

Avances en los estudios arqueológicos, geoarqueológicos y paleoambientales en las Sierras Orientales de Tandilia. Resultados preliminares de los sitios Alero El Mirador y Abrigo La Grieta

This paper presents the characteristics of the archaeological record of two sites recently taken up, called Alero El Mirador and Abrigo La Grieta. The study of different proxy data like lithic assemblages, zooarchaeological and paleoenvironmental record (obtained by diatoms, phytoliths and anthracology inferences) and their relationship to stratigraphic units, allows us to hypothesize anthropic management aspects of local natural resources and paleoclimatic events occurred in the eastern of Tandilia hill during different moments of the Pleistocene-Holocene archaeological sequence.Este trabajo presenta las características de los registros arqueológicos de dos sitios recientemente retomados, denominados Alero El Mirador y Abrigo La Grieta. Se dan a conocer los resultados del análisis de los conjuntos líticos, del registro zooarqueológico y paleoambiental (obtenidos a partir de la evidencias de diatomeas, antracología y fitolitos), y su relación con las unidades estratigráficas. Esta información proxy permite hipotetizar aspectos del manejo antrópico de recursos naturales locales y de eventos paleoclimáticos ocurridos en el sector serrano de Tandilia oriental durante distintos tramos de la secuencia Pleistoceno-Holoceno

Avances en los estudios arqueológicos, geoarqueológicos y paleoambientales en las Sierras Orientales de Tandilia: resultados preliminares de los sitios Alero El Mirador y Abrigo La Grieta

Este trabajo presenta las características de los registros arqueológicos de dos sitios recientemente retomados, denominados Alero El Mirador y Abrigo La Grieta. Se dan a conocer los resultados del análisis de los conjuntos líticos, del registro zooarqueológico y paleoambiental (obtenidos a partir de la evidencias de diatomeas, antracología y fitolitos), y su relación con las unidades estratigráficas. Esta información proxy permite hipotetizar aspectos del manejo antrópico de recursos naturales locales y de eventos paleoclimáticos ocurridos en el sector serrano de Tandilia oriental durante distintos tramos de la secuencia Pleistoceno-Holoceno.This paper presents the characteristics of the archaeological record of two sites recently taken up, called Alero El Mirador and Abrigo La Grieta. The study of different proxy data like lithic assemblages, zooarchaeological and paleoenvironmental record (obtained by diatoms, phytoliths and anthracology inferences) and their relationship to stratigraphic units, allows us to hypothesize anthropic management aspects of local natural resources and paleoclimatic events occurred in the eastern of Tandilia hill during different moments of the Pleistocene-Holocene archaeological sequence.Facultad de Ciencias Naturales y Muse

Avances en los estudios arqueológicos, geoarqueológicos y paleoambientales en las Sierras Orientales de Tandilia: resultados preliminares de los sitios Alero El Mirador y Abrigo La Grieta

Este trabajo presenta las características de los registros arqueológicos de dos sitios recientemente retomados, denominados Alero El Mirador y Abrigo La Grieta. Se dan a conocer los resultados del análisis de los conjuntos líticos, del registro zooarqueológico y paleoambiental (obtenidos a partir de la evidencias de diatomeas, antracología y fitolitos), y su relación con las unidades estratigráficas. Esta información proxy permite hipotetizar aspectos del manejo antrópico de recursos naturales locales y de eventos paleoclimáticos ocurridos en el sector serrano de Tandilia oriental durante distintos tramos de la secuencia Pleistoceno-Holoceno.This paper presents the characteristics of the archaeological record of two sites recently taken up, called Alero El Mirador and Abrigo La Grieta. The study of different proxy data like lithic assemblages, zooarchaeological and paleoenvironmental record (obtained by diatoms, phytoliths and anthracology inferences) and their relationship to stratigraphic units, allows us to hypothesize anthropic management aspects of local natural resources and paleoclimatic events occurred in the eastern of Tandilia hill during different moments of the Pleistocene-Holocene archaeological sequence.Facultad de Ciencias Naturales y Muse

Virus de Distemper Canino: detección molecular de diferentes aislamientos provenientes de perros de la provincia de santa fe, argentina, entre los años 2000 y 2010

In the city of Santa Fe, Argentina, during years 2000 and 2010, 13 wild type strains of canine distemper virus were isolated. All the samples were obtained from dogs with clinical signs of disease. Isolations were performed in MDCK cells which shown characteristic cytopathogenic effect. Identification of the wild type strains was performed by RT-PCR of a region that encodes NP nucleoprotein associated to RNA. The amplified product was a 287 bp corresponding to positions 769-1055 of the Onderstepoort and Lederle vaccine strains genome, which confirmed presence of the virus in all the samples. The isolate strains were tested by neutralization on MDCK cells with the monoclonal antibody against protein H, and only 6 of them were neutralized. This finding suggests the inability of the vaccine strains to protect the canines against the circulation of some wild type strains.Fil: Pinotti, M. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Gollan, A. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Canavesio, M. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Passeggi, C. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Larrateguy, M.V. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Paz, M.E. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Microbiología. Santa Fe, ArgentinaFil: Formentini, E. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Farmacología. Santa Fe, ArgentinaEn la ciudad de Santa Fe, Argentina, durante los años 2000 y 2010, se aislaron 13 cepas autóctonas del virus Distemper Canino. Las muestras se tomaron de caninos con signos clínicos de la enfermedad y consistieron en hisopados nasales, oculares, faríngeos (tonsilas) y conjuntivales. Los aislamientos se realizaron en células MDCK, las cuales mostraron efecto citopatogénico característico. Los virus provenientes de la cosecha, se detectaron por RT-PCR de una región que codifica la nucleoproteína NP asociada al RNA (posición 769 a la 1055 del genoma) obteniéndose en todos los casos un producto de 287 pb comparable con el obtenido con cepas vacunales (cepas Ondersterpoort y Lederle), lo que indica presencia viral en todas las muestras procesadas. Las cepas aisladas se sometieron a pruebas de neutralización en células MDCK con el anticuerpo monoclonal frente a la proteína H y sólo 6 de ellas fueron neutralizadas. Este hallazgo sugiere la incapacidad de las cepas vacunales para proteger a los caninos frente a la circulación de algunas cepas virales autóctonas

Chemical changes of titanium and titanium dioxide under electron bombardment

The electron induced effect on the first stages of the titanium (Ti0) oxidation and titanium dioxide (Ti4+) chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+)