1,226 research outputs found
Recent Advances on Ionic Liquid Uses in Separation Techniques
Ionic liquids (ILs) are non-molecular solvents; specifically, molten salts with low melting points, often below 100 °C and even below room temperature, thus allowing these solvents to remain liquid [1,2,3]. Chemically, they are formed by a bulky organic cation and a variety of usually smaller inorganic/organic anions to achieve electrical neutrality. Therefore, the number of combinations of cations and anions with substituted head-groups is unlimited, whereas the hydrophobicity range is guaranteed by the alkyl chain length of the organic moieties [4]. The physico-chemical properties of ILs include volatility, flammability, thermal stability, viscosity, solvation ability, an electrochemical window and relatively low toxicity, among others [1,2]. All of them can be tuned and modulated by the appropriate selection of both IL cation and anion—but what makes ILs so attractive? The main reason for their popularity is that they are considered a greener alternative to pollutant organic solvents, traditionally used in many technical and scientific fields, to decrease the environmental impact and overall risk of chemical exposure. Consequently, the scientific interest in ILs has been extended to different fields of chemistry with a high impact. In analytical chemistry, ILs have attracted special attention in separation techniques, where new ILs with specific properties, such as amphiphilic, magnetic and chiral properties, among others, are continuously being developed for new applications [3]. All this research has resulted in a rapid growth of the literature on the development and use of ILs, with an almost exponential increase, which usually involves books and Special Issues, such as the one we presented in Separations in 2019–2020.
The Special Issue (SI), entitled “Recent Advances on Ionic Liquid Uses in Separation Techniques”, was devoted to applications of ILs in chromatography, extraction for sample preparation and related techniques. The scope was extended to deep eutectic solvents (DES), which are a promising class of solvents with similar properties to ILs [5]. The SI gathered the collaborations of different authors with wide experience in the IL or DES fields that discussed the state-of-the-art preparation and application of IL-based composites and hydrophobic DES in analytical sample preparation, or presented new results in different HPLC modes for the analysis of basic compounds
La cromatografía líquida micelar: una técnica competitiva frente a la cromatografía líquida en fase inversa clásica
Resumen
Se presenta una serie de estudios en los que se compara el uso de sistemas cromatográficos de fase inversa micelares y acuo-orgánicos clásicos, para el análisis de varias familias de compuestos de interés en la industria farmacéutica (antidepresivos tricíclicos, ?-bloqueantes, diuréticos, esteroides y sulfonamidas), cuya elución cuando se emplean fases móviles acuo-orgánicas y fases estacionarias alquil-enlazadas convencionales, puede originar serios inconvenientes. Se muestran también tres aplicaciones de la cromatografía líquida micelar (CLM) al control de fármacos en preparados farmacéuticos y muestras de orina.
Las investigaciones realizadas se agrupan de la siguiente manera:
(i) comparación de las capacidades separativas de los sistemas cromatográficos micelares y acuo orgánicos clásicos y
(ii) desarrollo de nuevos procedimientos para la determinación de fármacos.
Las investigaciones de tipo fundamental abordan aspectos relacionados con las eficacias y simetrías de los picos cromatográficos, la fuerza eluyente, la resolución, la capacidad de screening de la CLM y la optimización de las condiciones de separación, considerando tanto la composición de la fase móvil como el pH. Se establecen unos principios básicos de selección del disolvente orgánico en las fases micelares, basados en la correlación existente entre la retención y la polaridad de los compuestos separados.
Se utilizan las mismas herramientas quimiométricas para realizar las comparaciones entre los dos sistemas de fase inversa, micelar y acuo-orgánico. En la bibliografía, no existe antecedente sobre estudios similares. El examen detallado del comportamiento cromatográfico de los compuestos de prueba que poseen una gran diversidad de estructuras, polaridades y comportamiento ácido-base, demuestra que la CLM es una técnica muy competitiva frente a la cromatografía de fase inversa clásica. Como aspectos relevantes presenta su menor toxicidad debido a la importante reducción de disolvente orgánico, sus características de retención que evitan la elución en gradiente, su particular selectividad, distinta de la cromatografía clásica, su versatilidad, la posibilidad de eluir compuestos muy apolares con ayuda de disolventes que se solubilizan gracias a la presencia de las micelas y la mejora espectacular de la forma de los picos de los compuestos básicos. Estas características permiten el uso de columnas convencionales de bajo precio y la posibilidad de inyectar directamente muestras con un elevado contenido en proteínas, como son las muestras fisiológicas.
Finalmente, los estudios aplicados se refieren al desarrollo de procedimientos para la determinación de antidepresivos tricíclicos en preparados farmacéuticos empleando fases móviles micelares y acuo orgánicas, que incluye una comparación de varias fases estacionarias, y la determinación del ? bloqueante propranolol a través del control de sus metabolitos y del diurético furosemida junto con sus productos de degradación, en muestras de orina y empleando la CLM.
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Summary
In this work, micellar and classical aqueous-organic chromatographic systems are compared in order to analyse several groups of interest in the pharmaceutical industry (tricyclic antidepressants, ?-blockers, diuretics, steroids and sulfonamides), which give rise to serious problems when eluting with aqueous-organic mobile phases and using conventional alkyl-bonded stationary phases. Micellar liquid chromatography (MLC) is also applied to the control of therapeutic active principles contained in pharmaceuticals and urine samples.
The research work is divided as follows:
(i) comparison of the chromatographic separation obtained with micellar and aqueous-organic systems and
(ii) developing of new procedures to the control of pharmaceutical products.
Fundamental studies consider aspects related to efficiencies and assymetries of the chromatographic peaks, elution strength, resolution, screening capability using MLC and optimisation of the separation conditions considering mobile phase composition and pH.
Some basic principles to select the organic solvent in micellar mobile phases are established. These are based on the correlation existing between retention and polarity of the compounds to separate.
The same chemometric tools are used to perform the comparison between the two reversed-phase systems, micellar and aqueous-organic modes. In the literature, it is not possible to find similar studies. A detailed examination of the chromatographic behaviour of the test compounds, showing a great diversity of structures, polarities and acid-base behaviour, revealed that MLC is a very competitive technique versus classical reversed-phase liquid chromatography. Some relevant aspects of micellar systems are: their low toxicity, due to the low amount of organic solvent used, the characteristics of retention, which avoid the use of a gradient mode, their particular selectivity, versatility, the possibility of eluting very low polar compounds, and a great improvement of the shape of the chromatographic peaks showed by basic compounds. This permits the use of low price conventional columns and the possibility of direct injection of samples with a high content of proteins.
Finally, the applied studies show three procedures to determine tricyclic antidepressants in pharmaceuticals using micellar and hydro-organic mobile phases, including the comparison of several stationary phases, and the control of the ?-blocker propranolol through its metabolites and the diuretic furosemide joint to its degradation products, in urine samples using MLC
Non-Query-Based Pattern Mining and Sentiment Analysis for Massive Microblogging Online Texts
Pattern mining has been widely studied in the last decade given its great interest for research and its numerous applications in the real world. In this paper the definition of query and non-query based systems is proposed, highlighting the needs of non-query based systems in the era of Big Data. For this, we propose a new approach of a non-query based system that combines association rules, generalized rules and sentiment analysis in order to catalogue and discover opinion patterns in the social network Twitter. Association rules have been previously applied for sentiment analysis, but in most cases, they are used once the process of sentiment analysis is finished to see which tokens appear commonly related to a certain sentiment. On the other hand, they have also been used to discover patterns between sentiments. Our work differs from these in that it proposes a non-query based system which combines both techniques, in a mixed proposal of sentiment analysis and association rules to discover patterns and sentiment patterns in microblogging texts. The obtained rules generalize and summarize the sentiments obtained from a group of tweets about any character, brand or product mentioned in them. To study the performance of the proposed system, an initial set of 1.7 million tweets have been employed to analyse the most salient sentiments during the American pre-election campaign. The analysis of the obtained results supports the capability of the system of obtaining association rules and patterns with great descriptive value in this use case. Parallelisms can be established in these patterns that match perfectly with real life events.COPKIT Project, through the European Union's Horizon 2020 Research and Innovation Programme
786687Spanish Ministry for Economy and Competitiveness
TIN2015-64776-C3-1-RAndalusian Government, through Data Analysis in Medicine: from Medical Records to Big Data Project
P18-RT-2947Spanish Ministry of Education, Culture, and Sport
FPU18/00150University of Granad
NOFACE: A new framework for irrelevant content filtering in social media according to credibility and expertise
Social networks have taken an irreplaceable role in our lives. They are used daily by millions of people
to communicate and inform themselves. This success has also led to a lot of irrelevant content and even
misinformation on social media. In this paper, we propose a user-centred framework to reduce the amount
of irrelevant content in social networks to support further stages of data mining processes. The system also
helps in the reduction of misinformation in social networks, since it selects credible and reputable users. The
system is based on the belief that if a user is credible then their content will be credible. Our proposal uses
word embeddings in a first stage, to create a set of interesting users according to their expertise. After that, in
a later stage, it employs social network metrics to further narrow down the relevant users according to their
credibility in the network. To validate the framework, it has been tested with two real Big Data problems on
Twitter. One related to COVID-19 tweets and the other to last United States elections on 3rd November. Both
are problems in which finding relevant content may be difficult due to the large amount of data published
during the last years. The proposed framework, called NOFACE, reduces the number of irrelevant users posting
about the topic, taking only those that have a higher credibility, and thus giving interesting information
about the selected topic. This entails a reduction of irrelevant information, mitigating therefore the presence
of misinformation on a posterior data mining method application, improving the obtained results, as it is
illustrated in the mentioned two topics using clustering, association rules and LDA techniques.European Commission 786687Andalusian government
FEDER operative program P18-RT-2947
B-TIC-145-UGR18University of Granada's internal plan PPJIB2021-04Spanish Government FPU18/0015
Our ten years of work on transparet box business simulation
Traditional business games are of the so-called black-box type (BBBS=Black box business
simulator); that is to say, the internal structure which generates the results of the simulation after
decision-making is not known. As a result, the player normally operates by trial and error and bases
his decisions on the symptoms of the problem (the observed behaviors of the system's variables)
and not on the real causes of the problem (the system's structure). Since 1988 José A.D. Machuca
has insisted that the business games based on System Dynamics models should be Transparent-box
business simulators (TBBSs). That means that, during the game, the user has access to the structure
of the underlying model and is able to relate it to the observed behaviors. The hypothesis is that
such transparency would facilitate causal reflection and favor systemic learning of business
problems.
In 1990, the G.I.D.E.A.O. Research Group took action on this idea and centered one of its
lines of research on this matter, with three main objectives: a) Creation of TBBSs, b) Introduction
of TBBSs in undergraduate and graduate Management courses as well as in executive training, c)
Experimentation in controlled environments in order to test the hypothesis mentioned in the above
paragraph. Now, ten years after the birth of the idea, we would like to share in this paper the results
obtained during that period
An E-pHEMT self-biased and self-synchronous class E rectifier
In this paper, the design of a self-biased and self-synchronous class E rectifier, based on an Enhancement-mode Pseudomorphic High Electron Mobility Transistor (E-pHEMT), is proposed. Characterized by a small value of the switch-mode time-constant (the on-state resistance times the output capacitance), high power efficiency figures may be obtained when forcing zero-voltage and zero-voltage-derivative switching conditions (ZVS and ZVDS). The self-synchronous operation, made possible by the device gate-to-drain coupling capacitance, leads to a compact design, while the gate-to-source Schottky junction allows self-biasing the gate terminal in order to improve the efficiency versus input power profile. Simulations, based on an extracted simplified non-linear model, are combined with measured results for implementations at 900 MHz and 2.45 GHz. Efficiency values as high as 76% and 64% have been estimated at power levels of -4 dBm and -1 dBm, respectively, with peak figures of 88% and 77%.This work was supported by MINECO through projects TEC2011-29126-C03-01, co-funded with FEDER, and Consolider CSD2008-0006
Dietary Intake, Nutritional Adequacy, and Food Sources of Selected Antioxidant Minerals and Vitamins; and Their Relationship with Personal and Family Factors in Spanish Children Aged 1 to <10 Years: Results from the EsNuPI Study
Minerals and vitamins involved in the antioxidant defense system are essential for healthy
growth and proper development during infancy. Milk and dairy products are of particular importance
for improving the supply of these nutrients to children. Indeed, the present study aimed to evaluate
the nutrient intake and food sources of zinc (Zn), selenium (Se), retinol and carotenoids (sources
of vitamin A), and vitamins C and E, and to analyze their relationships with personal and familiar
factors in Spanish children from the EsNuPI study. One subpopulation representative of the Spanish
population from 1 to <10 years old (n = 707) (reference group, REF) who reported consuming all
types of milk over the last year, and another subpopulation of the same age who reported consuming
fortified milk formulas (FMFs) (including follow-on formula, young child formula, growing up milk,
toddler’s milk, and enriched and fortified milk) (n = 741) (fortified milk consumers, FMCs) completed
two 24 h dietary recalls used to estimate their nutrient intakes and to compare them to the European
Food Safety Authority (EFSA) Dietary Reference Values (DRVs). The REF reported higher median
intakes than FMCs for Se (61 g/kg vs. 51 g/kg) and carotenoids (1079 g/day vs. 998 g/day).
Oppositely, FMCs reported higher intakes than REF for Zn (7.9 mg/day vs. 6.9 mg/day), vitamin
A (636 g/day vs. 481 g/day), vitamin E (8.9 mg/day vs. 4.5 mg/day), vitamin C (113 mg/day
vs. 71 mg/day), and retinol (376 g/day vs. 233 g/day). In the REF group, more than 50% of the
children met the EFSA recommendations for Zn (79.6%), Se (87.1%), vitamin A (71.3%), and vitamin
C (96.7%), respectively. On the other hand, 92.2% were below the EFSA recommendations for vitamin
E. In the FMC group, more than 50% of the children met the EFSA recommendations for Zn (55.2%),
Se (90.8%), vitamin A (75.7%), vitamin E (66.7%), and vitamin C (100%). We found statistically
significant differences between subpopulations for all cases except for Se. In both subpopulations,
the main sources of all antioxidant nutrients were milk and dairy products. For carotenoids, the
main sources were vegetables and fruits followed by milk and dairy products. A high percentage of
children had vitamins A and E intakes below the recommendations, information of great importance
to stakeholders. More studies using intakes and biomarkers are needed, however, to determine an
association with diverse factors of oxidative damage.Instituto Puleva de Nutricion (IPN)FENFINUTdairy company Lactali
Patrimonio, viñedo y turismo: recursos específicos para la innovación y el desarrollo territorial de Castilla-La Mancha
La revalorización del patrimonio cultural y la promoción del enoturismo constituyen factores indiscutibles de desarrollo en Castilla-La Mancha, puesto que, una vez integrados, desempeñan un papel clave en la consolidación de los procesos de gobernanza y en la creciente diversificación económica de las explotaciones agrarias. La implantación de estas estrategias está resultando bastante interesante en ciudades de tamaño medio como Alcázar de San Juan, ejemplo que permite descubrir la importancia de la construcción de capitales sociales territoriales para impulsar nuevos modelos productivos más sostenibles
Neuroprotective Effect of Bexarotene in the SOD1(G93A) Mouse Model of Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive weakness and muscle atrophy related to the loss of upper and lower motor neurons (MNs) without a curative treatment. There is experimental evidence suggesting that retinoids may be involved in ALS pathogenesis. Bexarotene (Bxt) is a retinoid-X receptor agonist used in the treatment of cutaneous lymphoma with a favorable safety profile whose effects have been recently investigated in other neurodegenerative diseases. In this study, we analyze the potential therapeutic effect of Bxt in the SOD1(G93A) mouse model of ALS. Mice were treated with Bxt or vehicle five times per week from day 60 onward. Survival, weight, and neuromuscular function studies together with histological and biochemical analyses were performed. Bxt significantly delayed motor function deterioration, ameliorated the loss of body weight, and extended mice survival up to 30% of the symptomatic period. Histological analyses of the lumbosacral spinal cord revealed that Bxt markedly delayed the early motor-neuron degeneration occurring at presymptomatic stages in ALS-transgenic mice. Bxt treatment contributed to preserve the MN homeostasis in the SOD1(G93A) mice. Particularly, it reduced the neuronal loss and the chromatolytic response, induced nucleolar hypertrophy, decreased the formation of ubiquitylated inclusions, and modulated the lysosomal response. As an agonist of the retinoic-X receptor (RXR) pathway, Bxt notably increased the nuclear expression of the RXRα throughout transcriptionally active euchromatin domains. Bxt also contributed to protect the MN environment by reducing reactive astrogliosis and preserving perisomatic synapsis. Overall, these neuroprotective effects suggest that treatment with Bxt could be useful in ALS, particularly in those cases related to SOD1 mutations
Why do motor neurons degenerate? Actualization in the pathogenesis of amyotrophic lateral sclerosis
Introducción: La esclerosis lateral amiotrófica (ELA) es la enfermedad degenerativa de las motoneuronas más frecuente. Aunque un peque?no porcentaje de los casos de ELA tienen un origen familiar y son secundarios a mutaciones en genes concretos, a la gran mayoría de ellos se les presupone un origen multifactorial, sin que su patogenia haya sido completamente aclarada. No obstante, en los últimos a?nos varios estudios han aumentado el conocimiento sobre la patogenia de la enfermedad, planteando la cuestión de si se trata de una proteinopatía, una ribonucleinopatía, una axonopatía o una enfermedad del microambiente neuronal. Desarrollo: En el presente artículo revisamos los trabajos publicados tanto en pacientes como en modelos animales de ELA y discutimos la implicación de los principales procesos celulares que parecen contribuir a su patogenia (procesamiento génico, metabolismo de proteínas, estrés oxidativo, transporte axonal y relación con el microambiente neuronal). Conclusiones: Aunque la patogenia de la ELA dista de estar aclarada, los estudios recientes apuntan a la idea de que hay unos desencadenantes iniciales que varían de unos sujetos a otros,y unas vías finales de degeneración de las motoneuronas que están implicadas en la mayor parte de los casos de enfermedad.Introduction: Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons. Although a small proportion of ALS cases are familial in origin and linked to mutations in specific genes, most cases are sporadic and have a multifactorial aetiology. Some recent studies have increased our knowledge of ALS pathogenesis and raised the question of whether this disorder is a proteinopathy, a ribonucleopathy, an axonopathy, or a disease related to the neuronal microenvironment. Development: This article presents a review of ALS pathogenesis. To this end, we have reviewed published articles describing either ALS patients or ALS animal models and we discuss how the main cellular pathways (gene processing, protein metabolism, oxidative stress, axonal transport, relationship with neuronal microenvironment) may be involved in motor neurons degeneration. Conclusions: ALS pathogenesis has not been fully elucidated. Recent studies suggest that although initial triggers may differ among patients, the final motor neurons degeneration mechanisms are similar in most patients once the disease is fully established
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