Biodegradable Polyester Films from Renewable Aleuritic Acid: Surface Modifications Induced by Melt-polycondensation in Air.

Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by meltcondensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parametersPeer reviewe

Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies

Background: Perfluoroalkyl substances (PFAS) and phthalates are synthetic chemicals widely used in various types of consumer products. There is epidemiological and experimental evidence that PFAS and phthalates may alter thyroid hormone levels; however, studies in children and adolescents are limited. Aim: To investigate the association of exposure to PFAS and phthalate with serum levels of thyroid hormones in European adolescents. Methods: A cross-sectional study was conducted in 406 female and 327 male adolescents (14–17 years) from Belgium, Slovakia, and Spain participating in the Aligned Studies of the HBM4EU Project (FLEHS IV, PCB cohort, and BEA, respectively). Concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were measured in sera from study participants, and urinary metabolites of six phthalates (DEP, DiBP, DnBP, BBzP, DEHP, and DiNP) and the non-phthalate plasticizer DINCH® were quantified in spot urine samples. Associations were assessed with linear regression and g-computational models for mixtures. Effect modification by sex was examined. Results: In females, serum PFOA and the PFAS mixture concentrations were associated with lower FT4 and higher FT3 levels; MEP and the sums of DEHP, DiNP, and DINCH® metabolites ( ∑DEHP, ∑DiNP, and ∑DINCH) were associated with higher FT4; ∑DEHP with lower FT3; and the phthalate/DINCH® metabolite mixture with higher FT4 and lower FT3. In males, PFOA was associated with lower FT4 and the PFAS mixture with higher TSH levels and lower FT4/TSH ratio; MEP and ∑DiNP were associated with higher FT4; and MBzP, ∑DEHP, and the phthalate/DINCH® metabolite mixture with lower TSH and higher FT4/TSH. PFOA, mono-(2-ethyl-5-hydroxyhexyl) phthalate (OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (oxo-MEHP), and monocarboxyoctyl phthalate (MCOP) made the greatest contribution to the mixture effect. Conclusions: Results suggest that exposure to PFAS and phthalates is associated with sex-specific differences in thyroid hormone levels in adolescent

Adipose tissue concentrations of persistent organic pollutants and total cancer risk in an adult cohort from Southern Spain: Preliminary data from year 9 of the follow-up

There is an increasing trend in the incidence of cancer worldwide, and it has been accepted that environmental factors account for an important proportion of the global burden. The present paper reports preliminary findings on the influence of the historical exposure to a group of persistent organic pollutants on total cancer risk, at year 9 in the follow-up of a cohort from Southern Spain. A cohort of 368 participants (median age 51 years) was recruited in 2003. Their historical exposure was estimated by analyzing residues of persistent organic pollutants in adipose tissue. Estimation of cancer incidence was based on data from a population-based cancer registry. Statistical analyses were performed using multivariable Cox-regression models. In males, PCB 153 concentrations were positively associated with total cancer risk, with an adjusted hazard ratio (95% confidence interval) of 1.20 (1.01–1.41) for an increment of 100 ng/g lipid. Our preliminary findings suggest a potential relationship between the historical exposure to persistent organic pollutants and the risk of cancer in men. However, these results should be interpreted with caution and require verification during the future follow-up of this cohort.This study was supported in part by research grants from the Spanish Ministry of Health (FIS 02/974, EUS2008-03574), CIBER de Epidemiología; Junta de Andalucía (01/264, P09-CTS-5488 Project of Excellence, PI-0675-2010, and PI-0513-2012), and the Instituto de Salud Carlos III (FIS PI11/0610)

Radiaciones ionizantes y su impacto Primer Simposio Internacional sobre Medioambiente (ISE 2017)

Son ya varias las décadas en las que en América Latina se ha trabajado arduamente sobre las radiaciones ionizantes; tanto en las ionizantes directas, tales como las partículas beta positivas y negativas, las partículas alfa, los protones, los mesones cargados, los muones y los iones pesados, así como también en las ionizantes indirectas (las producidas por partículas sin cargas), como las generadas por fotones con energías superiores a los 10 keV y los neutrones. Por otro lado, las radiaciones no ionizantes también han sido objeto de detallados estudios, y muy especialmente las provenientes del Sol, como el factor natural más influyente sobre la Tierra. En esta obra se presentan algunos de los avances en los que han participado reconocidos científicos latinoamericanos, como el Dr. Héctor Vega Carrillo, Dr. Daniel Palacios, Dra. Patrizia Pereyra, Dra. Sheila Serrano, y el Dr. Manuel Ernesto Delgado, entre otros. Esta obra puede ser de interés para profesionales del área de la protección radiológica, la ingeniería ambiental, física de la atmósfera y áreas afines, así como para estudiantes

Re-imaginando la clínica jurídica de derechos humanos

There are experiences that provide alternative perspectives on how best to configure a human rights clinic. One of these is provided by the proliferation of public interest and human rights (PIHR) law clinics (clínicas jurídicas de interés público y derechos humanos) in several Latin American countries. The goal of the article is to contribute to the debate on the best ways to pursue social justice through clinical education by importing a number of relevant insights drawn from the Latin American experience of the PIHR law clinics. The article also advances an original perspective: That a successful trajectory of these home-grown clinics in countries like Argentina, Chile, and Colombia can be contrasted constructively with the development of their counter parts at law schools in the United States. Several of the lessons learned from this Latin American model, it will be argued, are relevant to the addressing the methodological challenges described.Fil: Carrillo, Arturo J. Universidad George Washington. Facultad de Derecho. Clínica Jurídica de Derechos Humanos. Washington D. C., Estados UnidosFil: Yaksic, Nicolás Espejo. Universidad Central de Chile. Facultad de Ciencias Jurídicas y Sociales. Investigación y Postgrado. Santiago, Chile"Original publicado en inglés en: Carrillo, Arturo J. y Nicolás E. Yaksic, Re-imagining "The Human Rights Law Clinic", en Maryland Journal of International Law, nro. 26, pp. 80/112, 2011. Disponible en:https://digitalcommons.law.umaryland.edu/mjil/vol26/iss1/7/. -- Traducción: María Virginia Deymonnaz. Revisión: Federico De Fazio". -- Hay experiencias que proporcionan perspectivas alternativas sobre la mejor manera de armar una clínica de derechos humanos. Una de ellas es proporcionada por el aumento de las Clínicas Jurídicas de Interés Público y Derechos Humanos (PIHR) en varios países de América Latina. El objetivo de este artículo es contribuir al debate sobre las mejores maneras de perseguir la justicia social a través de la educación clínica mediante la importación de una serie de ideas relevantes extraídas de la experiencia latinoamericana de las clínicas jurídicas de interés público y derechos humanos. El artículo también presenta una perspectiva original que sostiene que una trayectoria exitosa de estas clínicas de cosecha propia en países como Argentina, Chile y Colombia puede ser contrastada de manera constructiva con el desarrollo de sus homólogas en las escuelas de derecho de los Estados Unidos de América. Varias de las lecciones aprendidas de este modelo latinoamericano, se argumenta, son relevantes para hacer frente a los desafíos metodológicos que se describen (en el trabajo)

Efectos de algunas variables macroeconómicas sobre los costos de operación de la maquinaria agrícola

The development of the agriculture sector depends on the efficiency of programs applied to the several processes of production, industrialization and commercialization. In order to get this efficiency is necessary to evaluate correctly the effect of the macroeconomics variables such as inflation, interest rates and exchange rates on the productivity of a particular enterprise. In agriculture, the farm machinery is a necessary factor to increase the work efficiency but its operation costs are important; so the costs have to be estimated correctly to elaborate adequate mechanization policies. In this study, the method of cash flow is utilized expressing the costs to present value, and an analysis of sensibility is carried out to identify the factors which affect more the costs of possession of farm machinery.

El propio entorno como el soporte para el diseño dle bloque "los seres vivos": el modelo del grupo Marmenor

Lo que empezó siendo un esfuerzo por adaptar el contenido medioambiental del programa de las Ciencias Naturales para la E.G.B. al estudio del Mar Menor y su campo ha ido derivando en una alternativa concreta para el conocimiento del entorno natural con una fundamentación y unas características propias, que se concretan en una secuencia y unos materiales que sirven de soporte a la acción sistemática y al cambio metodológico que proponemos y que intentaremos mostrar en estas Jornadas, así como las ayudas y dificultades que hemos encontrado para su realización