Overview of the novel sorbents available in solid-phase extraction to improve the capacity and selectivity of analytical determinations

Aquest article descriu els nous desenvolupaments en materials polimèrics que milloren l'extracció en fase sòlida (SPE) dels anàlits presents en mostres líquides. Se centra principalment en nous sorbents polimèrics, tant els comercialment disponibles com els sintetitzats per grups de recerca, amb propietats millorades per a l'extracció d'analits. Es descriuen diversos tipus de sorbents polimèrics, des dels que milloren la capacitat d'extracció (anomenats hypercrosslinked, amb elevada àrea superficial i hidrofilicitat) fins als que milloren la selectivitat del procés (els polímers d'empremta molecular [MIP] sintetitzats amb una cavitat específica per a l'analit d'interès) i també aquells que combinen ambdues propietats (coneguts com sorbents de mode mixt, que són sorbents d'elevada capacitat amb un grup d'intercanvi iònic que aporta la selectivitat en el procés d'extracció). També es presenten i es comparen resultats dels diversos sorbents quan s'apliquen a SPE d'analits en matrius dels camps d'aplicació analítics més rellevants.This article provides an overview of the most recent developments in polymer materials that improve the solidphase extraction (SPE) of analytes from liquid samples. The main focus is on new polymeric sorbents, both commercially available and “in-house” synthesized, whose enhanced properties allow suitable extraction. Several types of polymeric sorbents are described herein. Hypercrosslinked sorbents improve the capacity of the extraction process due to their large specific surface areas and balanced hydrophilicities. Molecularly imprinted polymers (MIPs) are synthesized with a specific cavity for the analyte of interest, improving extraction selectivity. Another type are mixed-mode sorbents that are high-capacity sorbents that contain an ion-exchange moiety that finetunes the selectivity of the extraction process. Finally, the results obtained when these sorbents are applied as SPE material to extract analytes in different liquid matrices are presented and comparatively discussed in the context of the most relevant analytical fields

'To 'seafood' or not to 'seafood'?' An isotopic perspective on dietary preferences at the Mesolithic-Neolithic transition in the Western Mediterranean

Stable isotope investigations of the Prehistory of the Western Mediterranean have increased exponentially during the last decade. This region has a high number of Mesolithic and Neolithic carbon and nitrogen isotope ratio data available compared with other world areas, resulting from the interest in the 'transition' between hunter-gathering and farming. This type of analysis is important as one of the few tools that give direct information on the poorly understood dietary transition from hunter-gatherer to agro-pastoralist subsistence in the Mediterranean Basin. Carbon and nitrogen stable isotope analysis on bulk collagen are especially useful for exploring marine vs. terrestrial protein input and therefore assess marine resource exploitation by these two different lifestyles. Gathering together all isotopic data for these chronologies we show that theWestern Mediterranean underwent a unique/distinct Neolithisation process. These data show a gradual dietary shift in aquatic resource consumption during the transition to farming that contrasts to elsewhere in Europe

Consequences of the Lack of IL-10 in Different Endotoxin Effects and its Relationship With Glucocorticoids

Sepsis constitutes one of the major causes of death in ICUs. In sepsis induced by gram-negative, although lipopolysaccharide (LPS) initially induces an exacerbated secretion of proinflammatory cytokines leading to endotoxic shock and death resembling a septic shock, it is also capable of inducing refractoriness to subsequent challenge with LPS, a state known as endotoxin tolerance, which is considered the initial step of the immunosuppression found in septic patients. As we previously demonstrated the importance of glucocorticoids in endotoxin tolerance, the aim of this study was to evaluate the contribution of Interleukin-10 (IL-10) both in the endotoxic shock and in the development of the tolerance and its relationship with glucocorticoids. Our results show that, upon LPS challenge, IL-10 knockout mice (KO) mice had an enhanced LPS sensitivity, along with elevated levels of proinflammatory cytokines as tumor necrosis factor-α, IL-12 and interferon-γ, and enhanced tissue damage, despite the high levels of glucocorticoids. This effect may be because, in part, of the higher expression of tumor necrosis factor receptors in IL-10 KO mice. Further, the injection of dexamethasone did not protect IL-10 KO mice from a LPS lethal challenge. Although tolerance was achieved in the absence of IL-10, it was weaker and the elevated levels of glucocorticoids were not able to reverse the high sensitivity of IL-10 KO mice to LPS. Nevertheless, glucocorticoids would play a pivotal role in the establishment and maintenance of this partial tolerance in IL-10 KO mice. Finally, our results show that IL-10 and glucocorticoids could act in a bidirectional way influencing the inflammatory and anti-inflammatory periods.Fil: Córdoba Moreno, Marlina Olyissa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Todero, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Fontanals, Adriana Mirta. Fundación Instituto Leloir; ArgentinaFil: Pineda, Gonzalo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Montagna, Daniela Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Yokobori, Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Ramos, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Barrientos, Gabriela Laura. Hospital Alemán. Laboratorio de Medicina Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Toblli, Jorge Eduardo. Hospital Alemán. Laboratorio de Medicina Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Isturiz, Martín Amadeo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Rearte, María Bárbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Morfologia i formació del complexe sinaptinèmic a espermatòcits i oòcits de Mus musculus

A method for the sequential study of synaptonemal complexes by light and electron microscopy has been used to characterize the synaptic process in mouse (Mus musculus) spermatocytes and oocytes. Pre- and post-synaptic figures can be easily identified

Matemática Financiera: Autoevaluación y rendimiento académico

Durante el curso 2006-2007, un equipo de profesores del Departamento de Matemática Económica, Financiera y Actuarial de la Universidad de Barcelona, relacionados con la asignatura de Matemática Financiera, vio la necesidad de adaptar materiales y crear nuevas formas para mejorar el aprendizaje, aprovechando el plan Bolonia. En nuestra facultad el número de alumnos siempre ha sido muy elevado y es una de las principales variables a tener en cuenta. En aquel curso, el volumen de alumnos que cursaban asignaturas relacionadas con la Matemática Financiera ascendió a 3.328. Utilizando Moodle hemos elaborado un material de aprendizaje y autoevaluación consistente en un banco de 218 preguntas. Con los datos completos de tres cursos académicos, desde 2008-2009 hasta el curso 2010-2011, los resultados de la experiencia se exponen en esta ponencia y se pueden calificar de esperanzadores

Hypercrosslinked polymer microspheres decorated with anion- and cation-exchange groups for the simultaneous solid-phase extraction of acidic and basic analytes from environmental waters

Mixed-mode ion-exchange sorbents were introduced to improve the selectivity and retention of solid-phase extraction (SPE) sorbents,. Mixed-mode ion-exchange sorbents integrate reversed-phase chemistry with ion-exchange groups to promote favourable interactions with ionic species. Nevertheless, a need to extract analytes with acidic and basic properties simultaneously within the same SPE cartridge led to the introduction of novel amphoteric/zwitterionic sorbents, which incorporate cation- and anion-exchange moieties within the same functional group attached to the polymeric network. In the present study, the development, preparation and SPE evaluation of two novel hypercrosslinked zwitterionic polymeric sorbents, functionalised with either strong anion-exchange (SAX) and weak cation-exchange (WCX) or weak anion-exchange (WAX) and strong cation-exchange (SCX) groups (namely HXLPP-SAX/WCX and the HXLPP-WAX/SCX), is presented for the simultaneous retention of acidic and basic compounds. The sorbents were prepared by a precipitation polymerisation route which yielded poly(divinylbenzene-co-vinylbenzylchloride) as a precursor polymer; subsequently, the precursor polymer was hypercrosslinked, to increase the specific surface areas and capacities of the sorbents, and then functionalised to impart the zwitterionic character. The HXLPP-SAX/WCX sorbent was decorated with quaternised sarcosine groups and the HXLPP-WAX/SCX sorbent was decorated with taurine moieties. The SPE parameters were optimised to exploit the ionic interactions between compounds and the functional groups. The optimal conditions involve a washing step to remove the compounds retained by hydrophobic interactions, thus increasing the selectivity. The optimised SPE protocol used the quaternised sarcosine-based sorbent followed by liquid chromatography and tandem mass spectrometry, and was applied to determine compounds with acidic and basic properties from environmental samples, such as river water and effluent wastewater samples, with excellent selectivity and matrix effect values below -30% and apparent recovery results ranging from 52% to 105% for most of the compounds. The analytical method was validated for environmental water samples and used in the analysis of samples in which some of the target compounds were found at ng L−1 concentration levels

Morfologia i formació del complexe sinaptinèmic a espermatòcits i oòcits de Mus musculus

A method for the sequential study of synaptonemal complexes by light and electron microscopy has been used to characterize the synaptic process in mouse (Mus musculus) spermatocytes and oocytes. Pre- and post-synaptic figures can be easily identified

Technical and cultural processes during the early Holocene in the NE of the Iberian Peninsula. The levels B and Bb of La Cativera (El Catllar, Tarragona)

[spa] Este trabajo presenta la estructura tecnológica observada en los niveles B y Bb (Boreal) de La Cativera, donde se observa una dualidad entre explotaciones laminares simplificadas y una producción de lascas cortas normalizadas. Una nueva datación inédita refuerza la posición cronológica de estos niveles pese a que las estrategias de talla de los mismos difieren significativamente de las documentadas en yacimientos sincrónicos. Los niveles B y Bb coinciden en el tiempo con los conjuntos del Mesolítico de Muescas y Denticulados, sin embargo el análisis tecnológico de la industria lítica lo pone en relación más directa con los conjuntos del Magdaleniense final y/o Epipaleolítico microlaminar propios del Tardiglaciar.[eng] This study presents the technological structure observed in levels B and Bb (Boreal) from La Cativera. A dual technological pattern is observed. For one side simplified blade exploitation is observed and for the other, a normalized short flake production is documented too. A new 14C data corroborates the chronological position of both levels despite showing technical schemes which significantly vary from those of synchronous sites. The B and Bb levels match in time with the so called Notched and Denticulate Mesolithic industries, however the observed knapping patterns present a major affinity with the Late Magdalenian or Epipalaeolithic Late Glacial knapping scheme