Stability and mixing behavior of vanadium-iron oxide monolayers on Pt(111) and Ru(0001) substrates.

Cation mixing is a well-recognized means to obtain oxides of desired functionality with predetermined structure and stoichiometry, which yet has been only little analyzed at the nanoscale. In this context, we present a comparative analysis of the stability and mixing properties of O-poor and O-rich two-dimensional V-Fe oxides grown on Pt(111) and Ru(0001) surfaces, with the aim of gaining an insight into the role of substrate and oxygen conditions on the accessible Fe contents. We find that due to the high oxygen affinity of the Ru substrate, the mixed O-rich layers are highly stable while the stability of O-poor layers is limited to inaccessibly oxygen-poor environments. In contrast, on the Pt surface, O-poor and O-rich layers coexist with, however, a much lower Fe content in the O-rich phase. We show that cationic mixing (formation of mixed V-Fe pairs) is favored in all considered systems. It results from local cation-cation interactions, reinforced by a site effect in O-rich layers on the Ru substrate. In O-rich layers on Pt, Fe-Fe repulsion is so large that it precludes the possibility of substantial Fe content. These findings highlight the subtle interplay between structural effects, oxygen chemical potential, and substrate characteristics (work function and affinity towards oxygen), which governs the mixing of complex 2D oxide phases on metallic substrates.

Mixing properties of Al2O3(0001)-supportedM2O3andMM'O3monolayers (M,M' = Ti, V, Cr, Fe).

Considering the importance of sub-monolayer transition metal oxides supported on another oxide in many industrial processes, with the help of a DFT +Uapproach, we provide information on the structural and electronic properties of pureM2O3and mixedMM'O3oxide monolayers (M,M' = Ti, V, Cr, Fe) supported on anα-Al2O3(0001) support. With their structure in the prolongation of the alumina corundum lattice, the monolayers have non-equivalent surface and interface cations, which leads to two different cation configurations in the mixed oxides. In all cases, the interfacial charge transfer is weak, but strong cation-cation electron redistributions may take place as in TiVO3, TiFeO3, VFeO3, and TiCrO3in which actual redox processes lead to cation oxidation states different from the expected +3 value. We show that the tendency to mixing relies on the interplay between two very different driving forces. Cation-cation redox reactions, in most cases, strongly stabilise mixed configurations, but preference for a given cation position in the monolayer, because of surface energy reasons, may strengthen, weaken or even block the mixing tendency. By comparison with results obtained in bulk ilmenite, in free-standing monolayers and in MLs deposited on transition metal substrates, we evidence the flexibility of their electronic structure as a function of size, dimensionality and nature of support, as a lever to tune their properties for specific applications.

Modelling the precipitation of nanoparticles in a closed medium in the presence of seeds: Application to amorphous silica synthesis.

Seed-mediated methods are widely used in industrial or academic laboratories for the synthesis of nanoparticles of controlled shape and size. In the natural medium, precipitation of secondary minerals also often take place on seeds. In this context, we have devised a formalism which accounts for the competition between seed growth and nucleation and growth of secondary particles in an initially over-saturated aqueous solution. Based on the classical nucleation theory, it involves a size-dependent growth law which accounts for Ostwald ripening effects, unlike most water-rock interaction codes. We find that, in such closed system, seed growth and nucleation/growth of secondary particles are strongly coupled. In the multi-dimensional parameter space, regions where one or the other process prevails are well-separated by a rather abrupt transition. In general, the value of the initial seed total surface area is insufficient to fully orientate the synthesis. Relying on this approach, we propose an alternative interpretation of recent experimental results on amorphous silica nanoparticle synthesis. Besides fundamental understanding of the kinetics of precipitation, the interest of the present approach is to serve as a guideline to experimentalists or industrialists working in seed-mediated syntheses and warn on the undesired formation of secondary particles when monodispersed distributions of nano- or micro-particles are searched.

Síndrome de mala dirección del humor acuoso crónico tras facoemulsificación: diagnóstico, tratamiento y factores a tener en cuenta / Chronic fluid misdirection syndrome of aqueous humor after phacoemulsification: diagnosis, treatment and asscociated factors

El síndrome de mala dirección del humor acuoso crónico es una entidad poco frecuente pero grave si no se trata de forma precoz. Presentamos el caso de un mujer que acude a nuestro servicio de urgencias con una presión intraocular de 43,00mmHg e hipotalamia en su ojo izquierdo. Como antecedente de interés fue intervenida de cirugía de cataratas en dicho ojo unas semanas antes. Ante la sospecha de glaucoma maligno se decidió realizar capsulotomía e iridotomía sin lograr buenos resultados. Por esta razón se decidió realizar una vitrectomía central, no respondiendo a este tratamiento quirúrgico tampoco. Así se realizó una segunda intervención que incluyó vitrectomía periférica, hialoidectomía anterior, zonulectomía e iridectomía; obteniendo buenos resultados. Finalmente se consiguió una bajada de la presión intraocular y una apertura del ángulo camerular. Por tanto si el cuadro no se resuelve en consulta con iridotomía y capsulotomía es precisa la realización de vitrectomía creando una cámara única que restablezca la fluídica del humor acuoso

The chronic fluid misdirection syndrome of aqueous humor is a rare and serious condition if not treated promptly. The case is presented of a woman attending the emergency department with an intraocular pressure of 43.00mmHg and shallow anterior chamber in her left eye. As clinical history of interest, she had cataract surgery in that eye several weeks before. Following the suspicion of malignant glaucoma, a capsulotomy and iridotomy were performed with an unfavourable outcome. For this reason, it was decided to perform a central vitrectomy, but the patient did not respond to this surgical treatment either. A second surgery was then performed with peripheral vitrectomy, anterior hyaloidectomy, zonulectomy, and iridectomy, obtaining good results. Finally, a decrease in intraocular pressure, and an opening of camerular angle were achieved. Thus, if malignant glaucoma is not resolved in medical consultation with iridotomy and capsulotomy, a vitrectomy, creating a unique chamber that restores the fluid mechanics of the aqueous humor, will be needed

Chronic fluid misdirection syndrome of aqueous humor after phacoemulsification: diagnosis, treatment and asscociated factors. / Síndrome de mala dirección del humor acuoso crónico tras facoemulsificación: diagnóstico, tratamiento y factores a tener en cuenta.

The chronic fluid misdirection syndrome of aqueous humor is a rare and serious condition if not treated promptly. The case is presented of a woman attending the emergency department with an intraocular pressure of 43.00mmHg and shallow anterior chamber in her left eye. As clinical history of interest, she had cataract surgery in that eye several weeks before. Following the suspicion of malignant glaucoma, a capsulotomy and iridotomy were performed with an unfavourable outcome. For this reason, it was decided to perform a central vitrectomy, but the patient did not respond to this surgical treatment either. A second surgery was then performed with peripheral vitrectomy, anterior hyaloidectomy, zonulectomy, and iridectomy, obtaining good results. Finally, a decrease in intraocular pressure, and an opening of camerular angle were achieved. Thus, if malignant glaucoma is not resolved in medical consultation with iridotomy and capsulotomy, a vitrectomy, creating a unique chamber that restores the fluid mechanics of the aqueous humor, will be needed.

Symbiotic performance and induction of systemic resistance against Cercospora sojina in soybean plants co-inoculated with Bacillus sp. CHEP5 and Bradyrhizobium japonicum E109.

Soybean is an economically very important crop throughout the word and particularly in Argentina. Soybean yield may be affected by many factors such as the lack of some essential nutrients or pathogens attack. In this work we demonstrated that the co-inoculation of the native biocontrol bacterium Bacillus sp. CHEP5 which induces resistance against Cercospora sojina in soybean and the nitrogen fixing strain Bradyrhizobium japonicum E109, was more effective in reducing frog leaf spot severity than the inoculation of the biocontrol agent alone. Probably, this is related with the increase in the ability to form biofilm when both bacteria are growing together. Furthermore, Bacillus sp. CHEP5 inoculation did not affect Bradyrhizobium japonicum E109 symbiotic behavior and flavonoids composition of root exudates in pathogen challenged plants. These results suggest that co-inoculation of plants with rhizobia and biocontrol agents could be a strategy to improve soybean production in a sustainable system.

Precipitation mechanism of amorphous silica nanoparticles: a simulation approach.

HYPOTHESIS: Despite its importance in numerous industrial and natural processes, many unsolved questions remain regarding the mechanism of silica precipitation in aqueous solutions: order of the reaction, role of silica oligomers, existence of an induction time and characteristics of the particle population. This may be traced back, in past models, to the lack of account of the first stages of nucleation, size dependence of the growth law, and full particle population. COMPUTATIONAL METHOD: A microscopic description of the nucleation and growth of amorphous silica nanoparticles is achieved which reproduces a large set of experimental measurements, under various thermodynamic conditions. The time evolution of the solution supersaturation and of the precipitate characteristics is established. FINDINGS: A growth law of order 6 allows reproducing experimental results, without being correlated to the presence of silica oligomers in the aqueous solution. The saturation plateaus are shown not to be due to an induction period. The characteristics of the particle population are more complex than assumed by simple precipitation models (Johnson-Mehl-Avrami-Kolmogorov or Chronomal models) and strongly depend on how supersaturation is reached. Such a microscopic approach thus proves to be well suited to elucidate the mechanism of nanoparticle formation in natural and industrial contexts.

Structural phase diagrams of supported oxide nanowires from extended Frenkel-Kontorova models of diatomic chains.

Relying on Frenkel Kontorova (FK) models of diatomic chains of increasing levels of complexity, this study presents an overall view of the diversity of structural effects that a compound (oxide) chain supported on a metal may display and helps assigning them to precise microscopic mechanisms. At each stage, the models are solved numerically, in order to provide phase diagrams as a function of chain-substrate interaction and misfit. Analytic derivations of transition lines are also provided within the continuum approximation. Their predictions are shown to quantitatively account for the numerical results, thus showing the validity of the continuum approximation in the misfit range under consideration. The present study thus extends our knowledge of the FK model by specifically focusing on diatomic chains and brings new information on a potentially interesting system which experimentalists just start being able to synthesize--oxide chains on metal substrates.

[Prevention of thromboembolism in bariatric surgery]. / Prevencíon del tromboembolismo en cirugía bariátrica.

Disease thromboembolic (ETEV) is one of the major complications that can occur after surgery, and is the leading cause of death in the postoperative period of Bariatric Surgery. Among other factors, should be aware that these patients are at additional risk of ETEV due to own obesity (IMC > 30). After Bariatric Surgery the risk of thromboembolic events varies according to the surveyed series. In general, it is estimated that danger EP (pulmonary embolism) is 0.8% and DVT (deep vein thrombosis) of 1.7%. ETEV global mortality estimates of 0.1 to 2%.

Switching prostaglandin analogues and 24-hour IOP fluctuations.

OBJECTIVES: To evaluate the fluctuations in 24h mean intraocular pressure (IOP) when switching prostaglandin analogues in patients with glaucoma. METHODS: Fourteen patients with primary open angle glaucoma were evaluated with monthly 24-hour IOP curves, using a monthly switching pattern of prostaglandin analogues and brinzolamide during 3 years of follow-up. RESULTS: Average IOP and average fluctuation (peak to through difference) were significantly higher with brinzolamide than with any of the analogues. There was no significant difference in either parameter with the different prostaglandin analogues, regardless of the order in which they were evaluated, or even if a month on brinzolamide was intercalated between the analogues. CONCLUSIONS: Brinzolamide was less effective than prostaglandin analogues in reducing 24-hour mean IOP and its fluctuations. Switching analogues had no significant effect on mean IOP or mean IOP fluctuations.

Rotación de análogos de prostaglandinas y fluctuaciones diurnas de la presión intraocular / Switching prostaglandin analogues and 24-hour iop fluctuations

Objetivos: Evaluar la eficacia de la rotación de análogos de prostaglandinas sobre las fluctuaciones de la presión intraocular (PIO) en 24h. Métodos: Se evaluó a 14 pacientes con glaucoma primario de ángulo abierto mediante curvas mensuales de presión intraocular de 24h, realizando un patrón de cambios mensuales del tratamiento hipotensor entre brinzolamida y análogos de prostaglandinas durante un período de tres años. Resultados: Tanto el promedio de PIO como el promedio de variación (diferencia entre el pico y el valle) durante las curvas fueron significativamente mayores con la brinzolamida que con cualquiera de los tres análogos. Tanto el promedio de PIO como el promedio de fluctuaciones fueron similares entre los tres análogos, independiente del orden en que se usaron o de si se intercaló un mes de brinzolamida entre uno y otro análogo. Conclusiones: La brinzolamida fue menos efectiva para reducir la PIO promedio y sus fluctuaciones durante 24h. No hubo un cambio significativo al rotar los análogos(AU)

Objectives: To evaluate the fluctuations in 24h mean intraocular pressure (IOP) when switching prostaglandin analogues in patients with glaucoma. Methods: Fourteen patients with primary open angle glaucoma were evaluated with monthly 24-hour IOP curves, using a monthly switching pattern of prostaglandin analogues and brinzolamide during 3 years of follow-up. Results: Average IOP and average fluctuation (peak to through difference) were significantly higher with brinzolamide than with any of the analogues. There was no significant difference in either parameter with the different prostaglandin analogues, regardless of the order in which they were evaluated, or even if a month on brinzolamide was intercalated between the analogues. Conclusions: Brinzolamide was less effective than prostaglandin analogues in reducing 24-hour mean IOP and its fluctuations. Switching analogues had no significant effect on mean IOP or mean IOP fluctuations(AU)

Prevención del tromboembolismo en cirugía bariátrica / Prevention of thromboembolism in bariatric surgery

La enfermedad tromboembólica (ETEV) es una de las complicaciones más importantes que pueden aparecer tras cualquier cirugía, y constituye la primera causa de muerte en el postoperatorio de cirugía bariátrica. Entre otros factores, se debe tener en cuenta que estos pacientes presentan un riesgo adicional de ETEV debido a la propia obesidad (IMC>30). Tras la cirugía bariátrica el riesgo de padecer eventos tromboembólicos varía según las series consultadas. En líneas generales, se estima que el peligro de EP (embolia pulmonar) es del 0,8% y el de TVP (trombosis venosa profunda) de 1,7%. La mortalidad global por ETEV se estima del 0,1 al 2%(AU)

Disease thromboembolic (ETEV) is one of the major complications that can occur after surgery, and is the leading cause of death in the postoperative period of Bariatric Surgery. Among other factors, should be aware that these patients are at additional risk of ETEV due to own obesity (IMC>30). After Bariatric Surgery the risk of thromboembolic events varies according to the surveyed series. In general, it is estimated that danger EP (pulmonary embolism) is 0.8% and DVT (deep vein thrombosis) of 1.7%. ETEV global mortality estimates of 0.1 to 2%(AU)

Evaluación de la actividad antimicrobiana de los extractos etanólicos de Azadirachta indica / Evaluation of the antimicrobial activity of Azadirachta indica ethanolic extracts

La presencia del acné juvenil, es una enfermedad que repercute directamente en la autoestima del adolescente, provocando en ocasiones inseguridad para establecer comu nicación y relaciones con otras personas, debido a su falta de confianza y respeto a su imagen. Debido a los altos costo del tratamiento para esta patología, el siguiente trabajo tuvo como objetivo determinar la actividad antimicrobiana de la Azadirachta indica y preparar una fórmula magistral (crema) antiacné. Los resultados obtenidos de la actividad antibacteriana de los extractos etanólicos de las hojas de Azadirachta indica A. Juss, mostraron que el Staphylococcus aureus presentó la mayor sensibilidad con una zona de inhibición de 15 mm. a una dilución 1/10; E. faecalis, con una sensibilidad de 7 mm, tanto en las diluciones 1/10 y 1/100; K. pneumoniae, con una zona de inhibición de 8 mm. y E. coli; mostró ser resistente a todas las diluciones ensayadas. Esta búsqueda sugiere que los principios activos extraídos con etanol de las hojas, pueden jugar un rol significativo en la acción inhibitoria contra el Staphylococcus aureus responsable del acné juvenil.

The presence of the youthful acne, is a disease that directly repels in the self-esteem of the adolescent, causing sometimes insecurity to contact and relations with other people, due to its lack of confidence and respect to its image. Due to high the cost of the treatment for this pathology, the following work had as objective to determine the antimicrobial activity of the Azadirachta it indicates and to prepare a skillful formula (Cream) antiacne. The obtained results of the antibacterial activity of the etanólicos extracts of the leaves of Azadirachta indica A. Juss, showed that the Staphylococcus aureus presented/displayed greater sensitivity with a zone of inhibition of 15 mm to a dilution 1/10; E. faecalis, with a sensitivity of 7 mm, as much in dilutions 1/10 and 1/100; K. pneumoniae with a zone of inhibition of 8 mm and E. coli, showed to be resistant all the tried dilutions. This search suggests them extracted active principles with ethanol of the leaves, can play a significant roll in the inhibiting action against the Staphylococcus aureus responsible for the youthful acne.

Plantilla de la sonrisa / Smiles’s Template

La valoración estética en reposo y en sonrisa es fundamental en la exploración clínica del paciente ortodóncico, dentro de la cual el análisis y diseño de la sonrisa se ha convertido en la última década en la llave del diagnóstico y del tratamiento. Se ha realizado una amplia revisión bibliográfica, donde los autores coinciden en valorar la sonrisa por la exposición gingival, por su relación labiodental, simetría y tamaño transversal de forma individual; sin embargo, de momento no existe en la bibliografía un modo de evaluar cada uno de estos factores de manera integral. Con el fin de incorporar el análisis exhaustivo de la sonrisa en la práctica clínica diaria, resulta necesario el uso de una plantilla a modo de esquema que nos permita registrar de manera rápida y sistemática cada una de las variables

The aesthetic evaluation of the face, both relaxed and smiling, is basic in the clinical exploration of the orthodontic patient. Within this valuation, the analysis and the design of the smile, has become the most important key issue for both the diagnostic and the treatment in the last decade. Extensive bibliographic revision has been made through which different authors agree to analyze the smile by its gingival exposure, lip and teeth relationship, symmetry, and transversal measure among others. Individually you cannot find throughout this literature a way to measure each of this factors in an integral way. In order to incorporate the exhaustive analysis of the smile on a daily clinical practice, it becomes necessary the use of a template as a scheme that allows us to quickly and systematically register each of these variables

Influence of prime-probe stimulus onset asynchrony and prime precuing manipulations on semantic priming effects with words in a lexical-decision task.

The present research examines semantic priming from attended and unattended parafoveal words. Participants made a lexical decision in response to a single central target. The target was preceded by two parafoveal prime words, with one of them (the attended prime) being precued by a peripheral cue. The main variables manipulated across experiments were cue informativeness (valid vs. neutral cues) and stimulus onset asynchrony (SOA) between prime and probe (200, 300, 600, or 1,000 ms). The results showed (a) reliable semantic priming from both attended and ignored prime words and (b) that the ignored priming effects were either negative or positive, depending on both the prime-probe SOA and cue informativeness. The present findings are discussed in relation to inhibitory versus episodic retrieval models of negative priming.