Glutamine: Metabolism and immune function, supplementation and clinical translation

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Glutamine is the most abundant and versatile amino acid in the body. In health and disease, the rate of glutamine consumption by immune cells is similar or greater than glucose. For instance, in vitro and in vivo studies have determined that glutamine is an essential nutrient for lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities, and neutrophil bacterial killing. Glutamine release to the circulation and availability is mainly controlled by key metabolic organs, such as the gut, liver, and skeletal muscles. During catabolic/hypercatabolic situations glutamine can become essential for metabolic function, but its availability may be compromised due to the impairment of homeostasis in the inter-tissue metabolism of amino acids. For this reason, glutamine is currently part of clinical nutrition supplementation protocols and/or recommended for immune suppressed individuals. However, in a wide range of catabolic/hypercatabolic situations (e.g., ill/critically ill, post-trauma, sepsis, exhausted athletes), it is currently difficult to determine whether glutamine supplementation (oral/enteral or parenteral) should be recommended based on the amino acid plasma/bloodstream concentration (also known as glutaminemia). Although the beneficial immune-based effects of glutamine supplementation are already established, many questions and evidence for positive in vivo outcomes still remain to be presented. Therefore, this paper provides an integrated review of how glutamine metabolism in key organs is important to cells of the immune system. We also discuss glutamine metabolism and action, and important issues related to the effects of glutamine supplementation in catabolic situations

Influence of the CO Adsorption Environment on Its Reactivity with (111) Terrace Sites in Stepped Pt Electrodes under Alkaline Media

The effect of the electrode potential in the reactivity of platinum stepped single crystal electrodes with (111) terraces toward CO oxidation has been studied. It is found that the CO adlayer is significantly affected by the potential at which the adlayer is formed. The electrochemical and FTIR experiments show that the adsorbed CO layer formed in acidic solution at 0.03 V vs SHE is different from that formed at −0.67 V vs SHE in alkaline solutions. The major effect of the electrode potential is a change in the long-range structure of CO adlayer. The adlayer formed in alkaline media presents a higher number of defects. These differences affect the onset and peak potential for CO stripping experiments. The stripping voltammogram for the adlayer formed at −0.67 V vs SHE always shows a prewave and the peak potential is more negative than that observed for the adlayer formed at 0.03 V vs SHE. This means that the apparent higher activity for CO oxidation observed in alkaline media is a consequence of the different CO adlayer structure on the (111) terrace, and not a true catalytic effect. The different behavior is discussed in terms of the different mobility of CO observed depending on the electrode potential. Also, the FTIR frequencies are used to estimate the pzc (potential of zero charge) for the Pt(111) electrode covered with a CO adlayer.M.J.S.F would like to thanks CNPq, Brazil, for financial support for his stay at Universidad de Alicante. This work has been financially supported by the MICINN (Spain) (project CTQ2010-16271) and Generalitat Valenciana (project PROMETEO/2009/045, FEDER)

Nuevos materiales didácticos para descubrir los aspectos más cotidianos de la Electroquímica

A pesar del amplio abanico de aplicaciones que posee la electroquímica, con importantes repercusiones en muchos aspectos de la vida cotidiana, los egresados de química de las universidades españolas poseen en general un notable desconocimiento de esta materia. Con objeto de hacer más atractivo el aprendizaje de esta parte de la química, al tiempo que se revelan algunas de sus aplicaciones menos conocidas, se han preparado nuevos materiales didácticos. En ellos se describen de manera divulgativa algunas de las aplicaciones más importantes de la electroquímica, como son las baterías, síntesis de aluminio, o su uso en biosensores. Los nuevos materiales se han suministrado al alumnado del primer curso del grado de química de la Universidad de Alicante y se ha pedido su opinión a través de una encuesta. En general la recepción ha sido buena, aunque la respuesta de los estudiantes ha sido algo escasa. Para dar mayor difusión, se está creando una página web con estos mismos contenidos. Esta página web se ha puesto a disposición de los alumnos de la asignatura Electroquímica de 4º curso de la licenciatura (plan a extinguir) de Química y de nuevo se pedirá su opinión a través de un formulario web

Adatom modified shape-controlled platinum nanoparticles towards ethanol oxidation

Different adatom modified shape-controlled Pt nanoparticles have been prepared and their electrocatalytic properties have been evaluated toward ethanol electrooxidation. Based on previous findings with Pt model surfaces, Sn, Rh, Ru and Pb adatoms have been selected as promising surface modifiers. The different adatoms have been gradually incorporated on the surface of the preferentially oriented (100) and (111) Pt nanoparticles under electrochemical conditions. The results obtained in 0.5 M H2SO4 indicated that, among the selected adatoms, Sn-modified nanoparticles displayed not only a significant shift to negative values on the onset potential of the ethanol oxidation, but also an important decrease on the hysteresis between the positive and negative sweeps. Interestingly, in chronoamperometic measurements at 0.6 V, the oxidation enhancement factors have been found to be dependent on the surface structure of the Pt nanoparticles. On the other hand, Ru and Pb-modified Pt nanoparticles only presented a rather small oxidation enhancement, whereas the activity of the Rh-modified Pt nanoparticles clearly diminished. In alkaline solutions, the oxidation mechanism changes, and the adsorption of Rh, Sn and Pb on the platinum surfaces just displays small catalytic effect at lower coverage for the potential onset in the voltammetric experiments. Ru adsorption does not present any positive effect over the reaction.This work has been financially supported by the Ministerio de Economía y Competitividad (project CTQ2013-44083-P) and Generalitat Valenciana (project PROMETEOII/2014/013)

Oxidation of ethanol on platinum nanoparticles: surface structure and aggregation effects in alkaline medium

The ethanol oxidation reaction in 0.1 M NaOH on Pt nanoparticles with different shapes and loadings was investigated using electrochemical and spectroscopic techniques. The surface structure effect on this reaction was studied using well-characterized platinum nanoparticles. Regardless of the type of Pt nanoparticles used, results show that acetate is the main product with negligible CO2 formation. From the different samples used, the nanoparticles with a large amount (111) of ordered domains have higher peak currents and a higher onset potential, in agreement with previous works with single crystal electrodes. In addition, spherical platinum nanoparticles supported on carbon with different loadings were used for studying possible diffusional problems of ethanol to the catalyst surface. The activity in these samples diminishes with the increase of Pt loading, due to diffusional problems of ethanol throughout the whole Pt nanoparticle layer, being the internal part of the catalyst layer inactive for the oxidation. To avoid this problem and prepare more dispersed nanoparticle catalyst layers, deposits were dried while the carbon support was rotated to favor the dispersion of the layer around the support. The improvement in the electrocatalytic activity for ethanol oxidation confirms the better performance of this procedure for depositing and drying.This work has been financially supported by the Ministerio de Economía y Competitividad and Generalitat Valenciana through projects CTQ2013-44083-P and PROMETEOII/2014/013, respectively

Influence of different cooling techniques on the surface roughness in milling operations of carbon steels

Comunicació presentada al 22rd International Congress on Project Management and Engineering CIDIP 2018 (Madrid, 11-13 July 2018)In machining processes the use of coolants and lubricants in the cutting zone is critical to reduce cutting forces, facilitate the chip removal and improve the surface quality of the workpiece. However, the influence of different coolant/lubricant techniques on the surface finish depends on many factors, such as the geometry of the cutting tool, material of the workpiece, cutting conditions, and so on. This paper studies the effect of different lubrication techniques such as: internal coolant, external coolant, dry cutting, air coolant and MQL lubrication (Minimum Quantity Lubrication) on the surface finish and the advantages and disadvantages of these systems for milling carbon steels. The study fundamentally analyzes the variations in roughness due to the built-up edge (BUE) and the minimum chip thickness in relation to the type of lubrication / cooling used.En los procesos de mecanizado la refrigeración / lubricación de la zona de corte es fundamental para conseguir menores fuerzas de corte, facilitar el arranque de viruta y mejorar la calidad superficial de la pieza. Sin embargo, la influencia de las diferentes técnicas en el acabado superficial depende de muchos factores, como la geometría de la herramienta de corte, material de la pieza de trabajo, condiciones de corte, etc. En esta comunicación se estudia el efecto de diferentes técnicas de lubricación como: lubricación interna, externa, en seco, con aire y con MQL (Minimum Quantity Lubrication) sobre el acabado superficial y se presentan las ventajas e inconvenientes de estos sistemas para el fresado de aceros al carbono. El estudio analiza fundamentalmente las variaciones de rugosidad debidas al efecto de filo recrecido (Built-up Edge, BUE) y del espesor mínimo de viruta en relación con el tipo de lubricación / refrigeración emplead

Predictors of Functional Outcomes following Operative Treatment of Acute Achilles Tendon Ruptures

Introduction: Previous studies involving operative management of Achilles tendon ruptures have attempted to determine if patient factors influence outcomes. No previous study has attempted to identify outcome predictors in patients exclusively undergoing surgical repair. The purpose of this study is to determine if any injury or patient variables were predictive of outcomes following operative management of Achilles ruptures. Methods: Patient demographics including age, sex, body mass index (BMI), comorbidities (diabetes mellitus, depression, anxiety), mechanism of injury (sports, non-sports), and date of injury were collected. Postoperative notes were reviewed to determine compliance. Patients completed the Foot & Ankle Ability Measure (FAAM)-Activities of Daily Living (ADL) and –Sports subscales, and visual analog scale (VAS) for pain. Multivariable regression analysis was performed, and regression coefficients with 95% confidence intervals and p-values were reported. Results: Female sex was associated with lower FAAM-Sports score (-10.11 [-19.73,-0.50]) and a lower Single Assessment Numeric Evaluation score from the FAAM-Sports subscale (-13.79 [-26.28,-1.30]; p=0.0325). History of anxiety was related to a lower FAAM-ADL score (-29.02 [-45.68, -12.36]; p=0.0009), FAAM-Sports score (-33.41 [-64.46, -2.37]; p=0.0368), and a higher VAS pain score (19.83 [4.43, 35.23]; p=0.0128). Age, BMI, a history of depression or diabetes mellitus, mechanism of injury, timing of repair, and patient compliance were not predictive. Discussion: Females and patients with anxiety have significantly poorer outcomes following Achilles tendon repair. Further study is indicated to determine whether these factors are also predictive of outcomes of Achilles ruptures treated non-surgically and how this may affect surgical indications in these patients

La elaboración del informe científico: los artículos científicos como referencia para la elaboración de informes de prácticas

El análisis, elaboración y presentación de resultados tanto experimentales como teóricos es una parte extremadamente importante en la investigación científica. Según nuestra experiencia docente, existe una notable carencia entre los estudiantes en su capacidad para la preparación de informes a partir de los trabajos experimentales realizados en el laboratorio. A veces esa carencia se agrava por no disponer de unos criterios claros de lo que debe aparecer en un informe científico. Por tanto, el trabajo de esta red será la búsqueda de metodologías para incentivar la obtención de competencias por parte del alumnado en lo que respecta a la preparación de informes de resultados de trabajos científicos, sean experimentales o de cálculo teórico. Se tomarán como guía los modelos universalmente utilizados en la bibliografía científica. De esta forma se logrará también familiarizar al alumnado en los cauces habituales de publicación de la investigación, usando ejemplos relacionados con el ámbito de la asignatura escogida (Cinética Química, 3er curso del Grado de Química)