Multiplicity of Th(IV) and U(VI) HEH[EHP] Chelates at Low Temperatures from Concentrated Nitric Acid Extractions.

Organophosphorus extractants have been widely investigated for lanthanide recovery from ore and for application in the reprocessing of spent nuclear fuel, such as in Advanced TALSPEAK schemes. Determining the speciation of the extracted metal complex in the organic phase remains a significant challenge. A better understanding of the variability of HEH[EHP]-actinide complexes and the speciation of chelates for tetra- and hexavalent actinides can improve the predictability of actinide phase transfer in such biphasic systems. In this study, the extraction of Th(IV) and U(VI) from nitric acid media using HEH[EHP] in heptane is examined. The distribution ratio as a function of nitric acid concentration was quantified using UV-vis spectroscopy, and then the speciation of HEH[EHP]-metal complexes in the organic phase was investigated using Fourier transform infrared (FTIR) spectroscopy and low-temperature 31P nuclear magnetic resonance (NMR) spectroscopy. In addition to perturbation of the vibrational modes proximal to the phosphonic moiety in HEH[EHP] in the FTIR spectra, the appearance of a nitrate signal was found in the organic phase following extraction from the highest acidity conditions for U(VI). The 31P NMR spectra of the organic phase at a low temperature (-70 °C) exhibited a surprising number (n) of resonances (n ≥ 7 for Th(IV) and n ≥ 11 for U(VI)), with the distribution between these resonances changing with the initial concentration of nitric acid in the aqueous phase. These results indicate that the compositions of the inner and outer spheres of the extracted actinides in the organic phase are more diverse than initially thought.

VSD-MOEA: A Dominance-Based Multiobjective Evolutionary Algorithm with Explicit Variable Space Diversity Management.

Most state-of-the-art Multiobjective Evolutionary Algorithms (moeas) promote the preservation of diversity of objective function space but neglect the diversity of decision variable space. The aim of this article is to show that explicitly managing the amount of diversity maintained in the decision variable space is useful to increase the quality of moeas when taking into account metrics of the objective space. Our novel Variable Space Diversity-based MOEA (vsd-moea) explicitly considers the diversity of both decision variable and objective function space. This information is used with the aim of properly adapting the balance between exploration and intensification during the optimization process. Particularly, at the initial stages, decisions made by the approach are more biased by the information on the diversity of the variable space, whereas it gradually grants more importance to the diversity of objective function space as the evolution progresses. The latter is achieved through a novel density estimator. The new method is compared with state-of-art moeas using several benchmarks with two and three objectives. This novel proposal yields much better results than state-of-the-art schemes when considering metrics applied on objective function space, exhibiting a more stable and robust behavior.

The thyroid hormone nuclear receptors and the Wnt/ß-catenin pathway: An intriguing liaison.

The thyroid hormones, T3 and T4, control several developmental and homeostatic processes. From a molecular point of view, most of their actions depend on the activity of the thyroid hormone nuclear receptors (TRs), which are T3-modulated transcription factors. Recent studies have not only highlighted that the physiological response induced by T3 within a cell depends on the expression of specific TRs, but also that the functions of TRs are coordinated by and integrated in other signalling pathways. This is particularly the case for the multilevel interactions between TRs and the Wnt signalling pathway. Interestingly both signals are involved in development and homeostasis, and their alterations are responsible for the development of pathologies, such as cancer. Here, we present findings on the complex crosstalk between TRs and Wnt in several organisms and in different tissue contexts, and speculate on the biological relevance of modulating TR-Wnt functionality in therapeutic approaches aimed to target cancer cells or applications for regenerative medicine.

Application of asymmetric flow field-flow fractionation (AF4) and multiangle light scattering (MALS) for the evaluation of changes in the product molar mass during PVP-b-PAMPS synthesis.

The use of polymers for the delivery of drugs has increased dramatically in the last decade. To ensure the desired properties and functionality of such substances, adequate characterization in terms of the molar mass (M) and size is essential. The aim of this study was to evaluate the changes in the M and size of PVP-b-PAMPS when the amounts of the synthesis reactants in the two-step radical reaction were varied. The determination of the M and size distributions was performed by an asymmetric flow field-flow fractionation (AF4) system connected to multiangle light scattering (MALS) and differential refractive index (dRI) detectors. The results show that the M of the polymers varies depending on the relative amounts of the reactants and that AF4-MALS-dRI is a powerful characterization technique for analyzing polymers. Using AF4, it was possible to separate the product of the first radical reaction (PVP-CTA) into two populations. The first population had an elongated, rod-like or random coil conformation, and the second had a conformation corresponding to homogeneous spheres or a microgel structure. PVP-b-PAMPS had only one population, which had a rod-like conformation. The molar masses of PVP-CTA and PVP-b-PAMPS found in this study were higher than those reported in previous studies.

Increased expression of the thyroid hormone nuclear receptor TRα1 characterizes intestinal tumors with high Wnt activity.

Our previous work demonstrated a key function of the thyroid hormone nuclear receptor TRα1, a T3-modulated transcription factor, in controlling intestinal development and homeostasis via the Wnt and Notch pathways. Importantly, increased expression of TRα1 in the intestinal epithelium in a mutated Apc genetic background (vil-TRα1/Apc+/1638N mice) accelerated tumorigenesis and contributed to a more aggressive tumor phenotype compared to that of the Apc mutants alone. Therefore, the aim of this study was to determine the relevance of this synergistic effect in human colorectal cancers and to gain insights into the mechanisms involved. We analyzed cohorts of patients by in silico and experimental approaches and observed increased TRα1 expression and a significant correlation between TRα1 levels and Wnt activity. TRα1 loss-of-function and gain-of-function in Caco2 cell lines not only confirmed that TRα1 levels control Wnt activity but also demonstrated the role of TRα1 in regulating cell proliferation and migration. Finally, upon investigation of the molecular mechanisms responsible for the Wnt-TRα1 association, we described the repression by TRα1 of several Wnt inhibitors, including Frzb, Sox17 and Wif1. In conclusion, our results underline an important functional interplay between the thyroid hormone nuclear receptor TRα1 and the canonical Wnt pathway in intestinal cancer initiation and progression. More importantly, we show for the first time that the expression of TRα1 is induced in human colorectal cancers.

Empathic orientation among medical students from three universities in Barranquilla, Colombia and one university in the Dominican Republic.

OBJECTIVE: To compare empathic orientation among medical students from three schools of medicine in Colombia and one in the Dominican Republic. MATERIAL AND METHODS: Empathic orientation of medical students was measured using the Jefferson Scale of Physician Empathy (JSPE), Spanish version for students (the "S" version) validated in Mexico and Chile, and culturally adapted to Colombia and the Dominican Republic. Data were compared using a three-factor analysis of variance (model III) and a discriminant analysis. RESULTS: No differences in empathic orientation were observed among courses and between sexes, but differences were found in schools of medicine considered as a unit in each studied country. CONCLUSIONS: Empathic orientation levels tend to reduce as courses advance. This was observed in both male and female students and in all schools analyzed.

Orientación empática en estudiantes de Medicina en una universidad de República Dominicana / Empathic orientation observed in medical students at one university in the Dominican Republic

Objetivo: determinar el nivel de orientación empática de los estudiantes de medicina de la Universidad Central del Este. Métodos: esta es una investigación no experimental, descriptiva, transversal y ex posfacto causa-efecto. La población estuvo constituida por 853 estudiantes (años: 1ro., 2do. 3ro., 4to. y 5to.), de la cual se tomó una muestra de 515 voluntarios (n = 108 del 1ro.; n = 151 del 2do.; n = 109 del 3ro.; n = 94 del 4to. y n= 53 del 5to.) Se aplicó, en 2012, la versión en español de la Escala de Empatía Médica de Jefferson (EEMJ) para estudiantes de Medicina (versión S), validada en México y Chile y adaptada culturalmente a República Dominicana por los autores del presente trabajo. Resultados: el nivel de orientación empática de los estudiantes fue bajo. No se encontraron diferencias significativas en las puntuaciones según nivel de la carrera. Sin embargo sí fue significativa la diferencia en las puntuaciones de género. Conclusiones: es necesario realizar más investigaciones para determinar cuáles son los factores que están influyendo en los resultados encontrados, por qué fueron bajos y cuáles son las condiciones (internas y externas) en que se desenvuelve el proceso de formación de los estudiantes de Medicina de la Universidad Central del Este de República Dominicana.

Objective: to determine the level of empathic orientation of the medical students in Universidad Central del Este in the Dominican Republic. Methods: non-experimental, descriptive, cross-section and ex posfacto cause-effect research study. The study population was 853 students from the first, second, third, fourth and fifth years of the career and the final sample consisted of 515 voluntary students (108 from 1st year, 151 from the 2nd, 109 from the 3rd, 94 from the 4th and 53 from the 5th. In 2012, the Spanish version of the Jefferson Scale of Physician Empathy was applied to medical students after being validated in Mexico and Chile and adapted from the cultural viewpoint by the authors of this paper to the Dominican Republic background. Results: the level of empathic orientation found in the Dominican students was low. There were no significant differences in scores by study year. However, the difference was significant in gender scores. Conclusions: it is required to carry out research studies in order to determine the factors that have an impact on the observed results, the reasons why these indexes were low and the internal and external conditions of the process of medical student formation in Universidad Central del Este in the Dominican Republic.

Orientación empática de estudiantes de medicina en tres universidades de Barranquilla, Colombia y en una universidad de República Dominicana / Empathic orientation among medical students from three universities in Barranquilla, Colombia and one university in the Dominican Republic

Objetivo. Comparar la orientación empática entre estudiantes de Medicina de tres facultades de Medicina de Colombia y una de República Dominicana. Material y métodos. Se midió la orientación empática de los estudiantes de Medicina mediante la escala de empatía médica de Jefferson, en la versión en español para estudiantes (versión S) validada en México y Chile, y adaptada culturalmente a Colombia y República Dominicana. Los datos se compararon mediante un análisis de varianza trifactorial (modelo III) y por un análisis discriminante. Resultados. No se encontraron diferencias de orientación empática entre los cursos ni entre los sexos, pero sí entre las facultades de Medicina consideradas como una unidad en cada uno de los países estudiados. Conclusiones. Los niveles de orientación empática tienden a disminuir a medida que los cursos avanzan. Este hecho se produce en estudiantes de ambos sexos y en todas las facultades analizadas.

Objective. To compare empathic orientation among medical students from three schools of medicine in Colombia and one in the Dominican Republic. Material and Methods. Empathic orientation of medical students was measured using the Jefferson Scale of Physician Empathy (JSPE), Spanish version for students (the "S" version) validated in Mexico and Chile, and culturally adapted to Colombia and the Dominican Republic. Data were compared using a three-factor analysis of variance (model III) and a discriminant analysis. Results. No differences in empathic orientation were observed among courses and between sexes, but differences were found in schools of medicine considered as a unit in each studied country. Conclusions. Empathic orientation levels tend to reduce as courses advance. This was observed in both male and female students and in all schools analyzed.

Orientación empática en estudiantes de odontología de la Universidad Central del Este / Empathic orientation in dental students of Universidad Central del Este

Objetivo: determinar la orientación empática en estudiantes de odontología. Metodología: es una investigación no experimental, descriptiva, de corte transversal y ex post facto causa-efecto. La población estuvo constituida por 284 estudiantes de la carrera de odontología de la Universidad Central del Este (República Dominicana) y la muestra se conformó con 239 sujetos, quienes cursaban los niveles 1º, 2º, 3º, 4º y 5º (Años), durante 2012. Se utilizó la Escala de Empatía Médica de Jefferson (EEMJ), versión S, adaptada culturalmente para la República Dominicana. Resultados: se analizaron las variables año y género. Se encontró que el factor año fue altamente significativo (p<0,001), contrario a resultados del factor género (p>0,05), lo cual indica que existen diferencias entre los años estudiados, pero no entre los géneros. Conclusiones: es necesario realizar estudios que favorezcan la observación de las variables estudiadas y compararlas con modificaciones hechas a nivel de los programas académicos y mallas curriculares.

Purpose: To determine the empathetic orientation of dental school students. Methods: This is a non-experimental, descriptive, transversal and ex post facto cause and effect study. The population consisted of 284 dentistry students from the Universidad Central del Este (Dominican Republic). The sample size was of 239 subjects, who were enrolled in level 1º, 2º, 3º, 4º and 5º (years) during 2012. We applied a culturally adapted Spanish version of the Scale of Physician Empathy Jefferson (JSPE). Results: We analyzed variables year and gender, finding that year was highly significant (p <0.001), in contrast to gender (p> 0.05). This indicates that there are differences in empathetic orientation between years but not between genders. Conclusions: Further studies should be conducted that favor the observation of the variables studied. When possible, comparative analysis should be made to determine the impact of changes made at the academic programs and curricula.