Colloidal systems for crystallization processes from liquid phase

Colloidal systems are involved in crystallization processes in many different ways: on one hand, colloids may be used as controlling or structure-directing agents, as nanoreactors and as scaffolds and templates for crystallization. On the other hand, it is very often desirable to obtain colloidal particles in a crystalline or nanocrystalline state. In this highlight, we cover the challenges and the recent advances on the following topics: (i) the use of polymer colloids as additives for crystallization due to their ability to control nucleation and growth and even to promote enantiomer resolution by enantioselective crystallization; (ii) state of the art in the preparation of inorganic crystalline colloids; and (iii) the application of colloidal systems (i.e., colloidal particles, droplets, micelles and vesicles) as supports, templates and nanoreactors for inorganic crystallization

Assembly of Ordered Polystyrene Nanoparticles on Self- Assembled Monolayers

Spontaneous assembly of nanoparticles onto a surface is a promising bottom-up concept for the fabrication of new functional materials that can be used for various applications in the nanotechnology. In this paper, we describe a system based on gold/polystyrene (Au/PS) Janus particles arranged onto Au self-assembled monolayer (SAM) of 1-dodecanthiol (NDA). The micro-size Au/PS Janus particles are self-assembled onto Au surface and are dissolved into polystyrene (PS) nanoparticles. The SAM of NDA plays two different roles; it dissolves the original Au/PS Janus particles and organizes the PS nanoparticles onto the Au surface. Overall, our proposed method for the assembly of large-scale area nanoparticles can be extended for further uses in the surface science

PROSA RITMICA E STILE IN DEMOSTENE E CICERONE

Il presente lavoro intende applicare un approccio maggiormente pragmatico e stilistico nella ricerca dell'importante fenomeno della prosa ritmica greca e latina. La compresenza di registri stilistici differenti in un medesimo punto dimostra con un grado di sicurezza maggiore l'intenzionalità delle scelte effettuate dagli oratori presi in esame

El desarrollo de una metodología híbrida para el estudio de las prácticas comunicativas en las regiones fronterizas de América del Sur

When we as new researchers embark on our first field research stay, we often face the challenge of bridging the gap between the project’s research design and the practical fieldwork. Drawing from my experiences in collecting data for my doctoral project, this article emphasizes the adaptability needed to adjust research designs as new knowledge emerges. More specifically, it also caters to those interested in conducting qualitative sociolinguistic research to gather data on the usage of contact languages. This article sheds light on my research design, primarily focusing on empirical data collection related to communicative practices in South American Portuñol and other languages in five border regions. It argues that the effective study of Portuñol practices across diverse borders requires consistent data collection methods that promote triangulation. Proposed methods are sociolinguistic interviews, documenting the linguistic landscape, and analysing official documents to comprehensively understand the regions’ diverse sociolinguistic behaviors.A medida que los jóvenes investigadores se embarcan en su primer viaje de investigación de campo, la mayoría de nosotros nos encaramos por primera vez con la discrepancia entre el mundo empírico y las consideraciones metodológicas que se establecieron en la fase preparatoria del diseño de investigación. Por más que éste parezca transferible a la recopilación de datos en el mundo real, son inevitables los cambios metodológicos. Basadas en mis propias experiencias recopilando datos para mi proyecto de doctorado, este artículo se dirige tanto a lectores interesados en explorar cómo elaborar una investigación cualitativa para la recogida de datos sobre el uso del portuñol sudamericano, como a jóvenes investigadores que se encuentran en las primeras etapas de su carrera para discutir la importancia de estar dispuesto al ajuste del diseño de investigación conforme la adquisición de nuevos conocimientos en el campo de estudio. En este artículo, se describe el diseño de investigación para la recopilación de datos empíricos sobre el uso de la lengua en contacto portuñol y otras lenguas en cinco regiones fronterizas sudamericanas mediante una metodología cualitativa de etnografía sociolingüística y lentes teóricos de lingüística poscolonial y la glotopolítica. Se argumenta que la metodología efectiva para estudiar el fenómeno lingüístico del portuñol sudamericano en áreas fronterizas diferentes requiere métodos de recopilación de datos comparables entre sí que aseguren la triangulación de datos, como entrevistas sociolingüísticas, el método del paisaje lingüístico y análisis de documentos oficiales para comprender la influencia de las políticas lingüísticas en las conductas sociolingüísticas en las zonas fronterizas

Toward efficient synthesis of porous all-carbon-based nanocomposites for enantiospecific separation

Chiral separation and asymmetric synthesis and catalysis are crucial processes for obtaining enantiopure compounds, which are especially important in the pharmaceutical industry. The efficiency of the separation processes is readily increased by using porous materials as the active material can interact with a larger surface area. Silica, metal–organic frameworks, or chiral polymers are versatile porous materials that are established in chiral applications, but their instability under certain conditions in some cases requires the use of more stable porous materials such as carbons. In addition to their stability, porous carbon materials can be tailored for their ability to adsorb and catalytically activate different chemical compounds from the liquid and the gas phase. The difficulties imposed by the functionalization of carbons with chiral species were tackled in the past by carbonizing chiral ionic liquids (CILs) together with a template to create pores, which results in the entire body of a material that is built up from the precursor. To increase the atomic efficiency of ionic liquids for better economic utilization of CILs, the approach presented here is based on the formation of a composite between CIL-derived chiral carbon and a pristine carbon material obtained from carbohydrate precursors. Two novel enantioselective carbon composite materials are applied for the chiral recognition of molecules in the gas phase, as well as in solution. The enantiomeric ratio of the l-composite for phenylalanine from the solution was (L/D) = 8.4, and for 2-butanol from the gas phase, it was (S/R) = 1.3. The d-composite showed an opposite behavior, where the enantiomeric ratio for phenylalanine was (D/L) = 2.7, and for 2-butanol from the gas phase, it was (R/S) = 1.3

Reducción de la cobertura social para los fármacos antiartrósicos sintomáticos de acción lenta: una iniciativa de desinversión en Argentina, 2015-2017

In April 2016, the National Institute of Social Services for Retirees and Pensioners discontinued its policy of 100% coverage for 159 drugs (the “social subsidy”), including symptomatic slow-acting drugs for osteoarthritis (SYSADOAs), due to insufficient evidence of significant clinical benefit. We evaluated the effect of this measure on the use of SYSADOAs as well as non-steroidal anti-inflammatory drugs (NSAIDs), which were unaffected by this policy change. We compared outpatient dispensations of SYSADOAs and NSAIDs from 2015 to 2017, measuring dispensed units, retail price, and out-of-pocket expenses for beneficiaries each month. After the change in coverage, there was a 61.6% total decrease in SYSADOA units dispensed, and a 63.4% decrease in the final sales price to the public, measured in constant values. Dispensation was not reoriented towards NSAIDs, which fell by 6.1%. The incidence of new treatments decreased (from 6.4 to 3.3 treatments per 1,000 beneficiaries per month), as did their continuity. Beneficiaries’ out-of-pocket spending on SYSADOAs increased by 75.8% (at constant values). Disinvestment in interventions with questionable therapeutic value is an important tool in working toward the sustainability of health systems.En abril de 2016, el Instituto Nacional de Servicios Sociales para Jubilados y Pensionados excluyó del subsidio social la cobertura al 100% de 159 fármacos, entre ellos, los antiartrósicos sintomáticos de acción lenta o symptomatic slow-acting drugs for osteoarthritis (SySADOA), por insuficiente evidencia de beneficio clínico significativo. Evaluamos el efecto de esta medida sobre la utilización de SySADOA y de los antiinflamatorios no esteroides (AINE), no afectados por la medida. Se compararon las dispensas ambulatorias de los SySADOA y los AINE de 2015 a 2017, midiendo unidades dispensadas, precio de venta al público y gasto de bolsillo del beneficiario para cada mes. Luego de la medida, descendieron un 61,6% los envases de SySADOA dispensados y un 63,4% el monto total del precio de venta al público, medido en valores constantes. La dispensa no se reorientó hacia los AINE, que descendieron un 6,1%. Disminuyó tanto la incidencia de nuevos tratamientos (de 6,4 a 3,3 tratamientos por 1.000 beneficiarios por mes) como su continuidad. El gasto de bolsillo de los beneficiarios en SySADOA aumentó un 75,8% (a valores constantes). La desinversión en intervenciones de valor terapéutico cuestionable es una herramienta valiosa para la sustentabilidad de los sistemas de salud

Photoluminescence Stokes shift and exciton fine structure in CdTe nanocrystals

The photoluminescence spectra of spherical CdTe nanocrystals with zincblende structure are studied by size-selective spectroscopic techniques. We observe a resonant Stokes shift of 15 meV when the excitation laser energy is tuned to the red side of the absorption band at 2.236 eV. The experimental data are analyzed within a symmetry-based tight-binding theory of the exciton spectrum, which is first shown to account for the size dependence of the fundamental gap reported previously in the literature. The theoretical Stokes shift presented as a function of the gap shows a good agreement with the experimental data, indicating that the measured Stokes shift indeed arises from the electron-hole exchange interaction.Comment: 8 pages, 4 figures, LaTe