Differentiation Between Ripening Stages of Iberian Dry-Cured Ham According to the Free Amino Acids Content

In this paper, the differentiation of three ripening stages, postsalting, drying, and cellar, of Iberian dry-cured ham has been carried out according to their free amino acids contents. Eighteen L-amino acids, alanine, 2-aminobutanoic acid, aspartic acid, cysteine, glutamine, glycine, histidine, hydroxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, and valine have been determined by gas chromatography with derivatization with N,O-bis(trimethylsilyl)-trifluoroacetamide. Gas chromatography-mass spectrometry was used to confirm the presence of the eighteen amino acids in the ham samples, and gas chromatography using a DB-17HT column and flame ionization detector was used for quantitative determination. Extraction with a mixture methanol-acetonitrile has been carried out, achieving recoveries in the range 52-164%. Methimazole was used as internal standard. Limits of detection ranged between 7.0 and 611.7 mg·kg-1. Free amino acids have been used as chemical descriptors to differentiate between the ripening stages. Principal component analysis and linear discriminant analysis have been used as chemometric techniques, achieving complete differentiation between the ripening stages. Alanine, tyrosine, glutamine, proline, 2-aminobutanoic acid, cysteine, and valine were the most differentiating amino acids.Junta de Andalucía the project P09-AGR-0478

Toxic metals from atmospheric particulate matter in food species of tomato (Solanum lycopersicum) and strawberry (Fragaria x ananassa) used in urban gardening. A closed chamber study

In this work, two plant foods, strawberry and tomato, were subjected to exposure to metals from synthetic airborne particles in a closed chamber experiment. The synthetic particles were obtained in the laboratory. Within the closed chamber, particles were added and recirculated for 4 days in a turbulent air stream, causing deposition on the different parts of the plants. They were evaluated because of their increasingly frequent cultivation in urban gardens of cities. The main objectives were to determine whether the species accumulate metals significantly, which species accumulate the most, and in which parts of the plant. Finally, an attempt was made to differentiate the accumulation of pollutants by surface deposition on leaves and fruits from the adsorbed metals into the leaf or the fruit by their stomata or cuticles. The concentration of heavy metals was quantified in fruits, leaves and the soil after exposure. Metals were evaluated as a whole and individually, both in dry and fresh weight basis. The decrease of particulate matter and metals in the air inside the chamber was also studied in order to evaluate the use of both food species as air purifier by vertical gardens. The concentration of metals in plants (mg kg− 1 ) and airborne particles (mg m− 3 ) was measured by microwave plasma optical emission spectroscopy (MP-AES). For the sake comparison of total amount of metals in the samples concentrations were normalized. Strawberries was the food species that accumulated the largest amount of metals. In a dry weight basis, tomato leaves and strawberry fruits were the parts of the plants with higher accumulation capacity of particles and metals. The potential toxic elements Cd, Ni and Cr in tomato leaves and in strawberry fruits had a higher presence in the interior of the plant system. In a fresh weight basis, the strawberry fruit had the most accumulation capacity for metals.Fondo Europeo de Desarrollo Regional (FEDER) - UNSE15-CE-2845, P2016/70

A Practical Example on Uncertainty Evaluation: Spectrophotometric Determination of pKa

A practical example, focused on the evaluation of uncertainty and its propagation in spectrophotometric determination of ionization constants, is proposed in this work. The Hildebrand - Reilley method has been used in order to calculate the acetaminofen pKa value. After applying this method a linear relationship between pH and a logarithmic term depending on absorbances, was established. The value of pKa is obtained as the intercept of this straight-line and its error is evaluated from least squares calculations. As errors in both variables have to be considered, weighted least squares (WLS) must be used. The evaluation of uncertainty in pH measurements was carried out according to IUPAC recommendations in the case of glass electrode with two calibration standards. The uncertainty contributions of absorbance and work standard concentration, evaluated according to GUM, have been propagated to Hildebrand – Reilley expression in order to obtain the errors to be used in WLS calculations. Due to the different topics included in this tutorial, it can be considered as a useful tool for training people learning about the evaluation of uncertainty in measurements and its propagation

Nuevas bases de schiff para el análisis de trazas metálicas

Es ya conocida por todos las tradición de que goza la “escuela de Sevilla” en el análisis de trazas, y la extensión y amplitud de sus hallazgos y publicaciones en el campo espectrofotométrico. La labor de búsqueda ha sido enorme, y tras una etapa inicial en que se puso énfasis sobre las bases de Schiff de tiosemicarbacida con aldehídos y cetonas, especialmente de tipo pridínico, se fueron considerando bistiossemicarbazonas, feniltiosemicarbazonas, y otros análogos. Ya en fecha más reciente se ha abordado el estudio de piridilhidraznoas y de derivados de carbohidracida, tiocarbohidracia y diaminoguanidina. Lógicamente, han sido muy numerosos los reactivos propuestos hasta la fecha, así como la variedad de las determinaciones y problemas resueltos. La evolución que el tiempo y la labor realizada han impuesto, nos han empujado a depurar y seleccionar, cada vez más, las variantes estructurales ensayadas y el propio campo de aplicación, y en este sentido pueden formularse los objetivos que subyacen en el presente trabajo. Citemos tres planteamientos posibles: a) Sintetizar reactivos que reunan en una misma molécula agrupaciones tipo, que previamente hubieran sido ensayadas y estudiadas por nosotros. b) Búsqueda de compuestos que permitieran la determinación de los diversos tipos de iones de la tabla periódica. c) Que los reactivos puedan utilizarse bajo metodología espectrofotométrica ó fluorimétrica. Esta triple vía se ha intentado en la presente Tesis, que explica, también, su división en dos partes ó apartados genéricos: El primero centrado sobre el uso de bases de Schiff dobles asimétricas, que intentan evaluar en un solo compuesto dos agrupaciones de características analíticas diferentes. El segundo pretende, por una parte, disponer de reactivos de iones, que hasta ahora mostraban pocas reacciones coloreadas con tiosemicarbazonas, carbohidrazonas, etc., aprovechando al mismo tiempo que las citadas reacciones tienen propiedades fluorescentes. En la introducción se ven con más detalles los puntos antes citados. Con el objeto de obtener reactivos que reúnan en una misma molécula agrupaciones tipo previamente ensayadas y que sirvan para determinar diversos tipos de iones se han sintetizado y caracterizado los siguientes compuestos: biacetilmono (2-piridil) hidrazona tiosemicarbazona (bpht); biacetilmono(2-piridil)hidrazona semicarbazona (bphs); biacetilmono(2-piridil)hidrazona tiocarbohidrazona(bphtc); bis(biacetilmono(2-piridil)hidrazona) carbohidrazona(bbphc); salicilaldehido oxalilhidrazona(saoh). Se estudian diversos parámetros físico-químicos de BPHT BPHTC SAOH así como su reaccionabilidad frente a los iones metálicos. Se proponen métodos de determinación fotométrica de Ni (ii) Cu(ii) Fe(ii) y Co(ii) con BPHT aplicándose a la determinación de estos metales en aleaciones metálicas. Se propone una determinación fluorimétrica de Al(iii) con SAOH

Some Asian Women Pioneers of Chemistry and Pharmacy

At present, several countries on the Asian continent are still very closed off to the idea of allowing not only the work of women, but also even the fact that they can study university degrees and, after finishing them, go on to practice their professions. In addition, if we go back to the beginning of the 20th century, this situation was even more serious. However, this was not an impediment for some women from these countries to achieve their goals of pursuing higher education and then serving society with their work. This article is dedicated to showing the biographies of three of them, the Indian chemist Asima Chatterjee and Philippine pharmacists Matilde S. Arquiza and Filomena Francisco. The most relevant features of their personal and professional lives are presented and previous biographies about them are completed. The main objective of this work is to show these figures to society and hold them up as references to other people, and the methodology followed has been the search for data about their lives and work that would allow us to complete the previous existing biographies about them. A brief biography on Janaki Ammal, the first Indian woman to obtain a doctorate, is also included

Gertrude Belle Elion, Chemist and Pharmacologist, Discoverer of Highly Relevant Active Substances

Gertrude Belle Elion was a woman who had to overcome many difficulties to achieve her dream of studying to be able to cure illnesses, especially those of the heart. These difficulties were imposed both by the limited economic resources of herself and her family, which did not allow her to pay the academic fees of the university in which she wanted to enroll, as well as gender, since she also had to fight against inequalities of that type prevalent in the society of her time. However, and despite these obstacles, she managed to graduate in Chemistry, based on interest, effort and tenacity, and later began a research career full of successes, which led her to discover relevant active substances which allow her to be awarded the Nobel Prize in Physiology or Medicine in 1988. This article presents the most relevant features of her personal and professional life and completes previous biographies about her life. Its main objective is to reintroduce her to society and put her as a reference to other people. The methodology followed has been the search for those data about her life and work that would allow completing the previous existing biographies about her

Pioneering Black African American Women Chemists and Pharmacists

It is assumed that the history of modern science in Africa began between the last two decades of the 19th century and the first two or three of the 20th century. It is true that in our days there are important female figures who were born on the continent, such as the Ph.D. in Chemistry Fatma Hamad, from Tanzania, or the Egyptian Shendy Nada, Ph.D. in Physics, the Ugandan Florence Mutonyi D’ujanga, Ph.D. in Mathematics and the Mozanbiquela Sarifa Abdul Magide Fagild or Kenyan MaryAbukutsa-Onyango, Ph.D. in Sciences, but the global development of science in Africa, from scientific, health, or literature points of view referring to women date back to the 19th century. However, the people of African descent, both men and women, who promoted the development of this modern science in Africa were, in the main, born in the United States, within families of strong African descent, what has come to be called Black families, and another general characteristic of these people is that they all belonged to the Black race. This article shows the biographies of four women of these characteristics, who achieved important milestones in the fields of Chemistry and Pharmacy and who contributed in a notable way, with their knowledge and their work, to the development of African science. They are Alice Ball, chemist and pharmacist, and Patricia Bath, Mary Elliott Hill and Marie Mainard Daly, graduated in Chemist, who made remarkable discoveries throughout their professional lives. The objective of the article is to highlight the contributions of these four women and show them as a models and examples for the rest of the women who want to follow in their footsteps. Finally, some brief brushstrokes on the lives and work of several other BBlack women of Black descent, also of BBlack race and born in the United States, like the previous ones, are also indicated, who in a similar way contributed greatly to the development of the current African science

Gertrude Belle Elion, Chemist and Pharmacologist, Discoverer of Highly Relevant Active Substances

Gertrude Belle Elion was a woman who had to overcome many difficulties to achieve her dream of studying to be able to cure illnesses, especially those of the heart. These difficulties were imposed both by the limited economic resources of herself and her family, which did not allow her to pay the academic fees of the university in which she wanted to enroll, as well as gender, since she also had to fight against inequalities of that type prevalent in the society of her time. However, and despite these obstacles, she managed to graduate in Chemistry, based on interest, effort and tenacity, and later began a research career full of successes, which led her to discover relevant active substances which allow her to be awarded the Nobel Prize in Physiology or Medicine in 1988. This article presents the most relevant features of her personal and professional life and completes previous biographies about her life. Its main objective is to reintroduce her to society and put her as a reference to other people. The methodology followed has been the search for those data about her life and work that would allow completing the previous existing biographies about her

Cómo enseñar en el aula universitaria

Resumen basado en el de la publicaciónSe analiza la repercusión que está teniendo el proceso de Bolonia en la mejora de la docencia en la universidad lo que está suponiendo una actualización didáctica y constante del profesorado universitario. Se hace hincapié en vincular la integración de las Tecnologías de la Información y la Comunicación (TIC) en la enseñanza universitaria y de su utilización como herramienta educativa más, tanto por parte de los docentes como de los estudiantes universitarios, lo que supone una transformación de la docencia mucho más centrada en el alumno mediante la utilización de plataformas e-learning y el uso de recursos digitales. Supone un nuevo escenario para profesores y alumnos.MadridBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; [email protected]