Soluble iron dust export in the high altitude Saharan Air Layer

Every summer huge amounts of desert dust particles are exported from the hyperarid subtropical Sahara to the North Atlantic the so-called Saharan Air Layer (SAL), a dry, warm and dust-laden corridor that expands from the North African coast (1-5 km.a.s.I.) to the Americas above the marine boundary layer. Because of the potential impact of the dust deposited on the ocean on marine biogeochemistry and climate, we studied the Fe solubility (in seawater) of atmospheric aerosols samples directly collected in the SAL off the North African coast, i.e, the fresh aerosols recently exported from the Sahara in the SAL. The aerosol sampling was performed at 2400 m.a.s.l. in Izana observatory in Tenerife island. In the total aerosols, we found low Fe concentrations and high fractional Fe solubility (FFS-2%) in the North Atlantic free troposphere airflows and high Fe concentrations and low FFS (-0.7%) within the SAL; the resulting FFS versus total dust (or total Fe) plot shows a hyperbolic trend attributed to the conservative mixing of 'fine combustion aerosols' and 'lithogenic mineral dust'. We then focused on the soluble Fe in the SAL Our results indicate that 70% of soluble Fe is associated with the dissolution of submicron dust particles, probably involving Fe-bearing clays. We found a FFS of submicron dust (-6%) higher than that typically observed in submicron particles of soil dust samples (<1%).This study is part of the project AEROATLAN e 2015-66229 -, funded by the Ministry of Economy and Competitiveness of Spain. M.I. García holds a research grant e TESIS20120054 e co-funded by the Canarian Agency for Research, Innovation and Information Society and the European Social Fund

Duas décadas de Acta Colombiana de Psicología: uma análise bibliométrica

The aim of the present study was to conduct a bibliometric analysis of the journal Acta Colombiana de Psicología, by virtue of its two decades of uninterrupted work (1998-2017). Initially, historical elements are described in the trajectory of the journal and its chronological evolution is revealed from a database that in its final sample took into account 388 scientific articles. Subsequently, the appraisal of the productivity indices (Lotka) as well as of the topics and methodologies used was carried out. Likewise, an appraisal of the collaboration indicators and the relationships between the authors with respect to the signatory countries was performed. The results highlight the large number of papers from Mexican institutions, a sustained increase in collaboration is visualized -which is evident in the Lawani and Subramanyam indices-, and it is found that the largest amount of papers focused on the areas of clinical and health psychology. The analysis undertaken allows showing what the journal has achieved throughout two decades of scientific work during which it contributed fundamentally to the development of psychology in Latin America.O objetivo do presente estudo foi realizar uma análise bibliométrica da revista Acta Colombiana de Psicología, devido a suas duas décadas de trabalho ininterrupto (1998-2017). Inicialmente, descrevem-se elementos históricos na trajetória da revista e revela-se sua evolução cronológica a partir de uma base de dados que considerou 388 artigos científicos em sua amostra final. Posteriormente, foram realizadas as análises dos índices de produtividade (Lotka) e das temáticas e metodologias utilizadas. Além disso, foi desenvolvida uma análise dos indicadores de colaboração e das relações entre os autores com respeito aos países signatários. Nos resultados, destaca-se a grande quantidade de trabalhos provenientes de instituições mexicanas, visualiza-se uma alta prolongada na colaboração - o que se evidencia nos índices de Lawani e Subramanyam -, e nota-se que a maior quantidade de trabalhos concentrou-se nas áreas de psicologia clínica e da saúde. A análise realizada permite exibir o feito da revista ao longo de duas décadas de trabalho científico nas quais colaborou de maneira fundamental para o desenvolvimento da psicologia na América espanhola.El objetivo del presente estudio fue realizar un análisis bibliométrico de la revista Acta Colombiana de Psicología, debido a sus dos décadas de trabajo ininterrumpido (1998-2017). Inicialmente, se describen elementos históricos en la trayectoria de la revista y se releva su evolución cronológica a partir de una base de datos que consideró 388 artículos científicos en su muestra final; posteriormente, se realizaron los análisis de los índices de productividad (Lotka) y de las temáticas y metodologías utilizadas. Asimismo, se desarrolló un análisis de los indicadores de colaboración y de las relaciones entre los autores con respecto a los países firmantes. En los resultados se destaca la gran cantidad de trabajos provenientes de instituciones mexicanas, se visualiza un alza sostenida en la colaboración -lo que se evidencia en los índices de Lawani y Subramanyam-, y se encuentra que la mayor cantidad de trabajos se enfocó en las áreas de psicología clínica y de la salud. El análisis realizado permite exhibir lo realizado por la revista a lo largo de dos décadas de trabajo científico en las que se aportó de manera fundamental al desarrollo de la psicología en Hispanoamérica

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

New natural sesquiterpenes as modulators of daunomycin resistance in a multidrug-resistant Leishmania tropica line

The effects produced by nine dihydro-β-agarofuran sesquiterpenes isolated from Crossopetalum tonduzii (1-8) and Maytenus macrocarpa (9) (Celastraceae) on the reversion of the resistant phenotype on a multidrug- resistant Leishmania line and their binding to recombinant C-terminal nucleotide-binding domain of Leishmania P-glycoprotein-like transporter were studied. The structures of the new compounds (1-5) were elucidated by spectroscopic methods, including 1H-13C heteronuclear correlation (HMQC), long-range correlation spectra with inversal detection (HMBC), ROESY experiments; and chemical correlations. The absolute configuration of one of them (1) was determined by CD studies. The structure-activity relationship is discussed.Peer Reviewe

Chemosensitization of a multidrug-resistant Leishmania tropica line by new sesquiterpenes from Maytenus magellanica and Maytenus chubutensis

Parasite resistance to drugs has emerged as a major problem in current medicine, and therefore, there is great clinical interest in developing compounds that overcome these resistances. In an intensive study of South American medicinal plants, herein we report the isolation, structure elucidation, and biological activity of dihydro-β-agarofuran sesquiterpenes from the roots of Maytenus magellanica (1-14) and M. chubutensis (14-17). This type of natural products may be considered as privileged structures. The structures of 10 new compounds, 1, 3, 6-9, and 12-15, were determined by means of 1H and 13C NMR spectroscopic studies, including homonuclear (COSY and ROESY) and heteronuclear correlation experiments (HMQC and HMBC). The absolute configurations of eight hetero- and homochromophoric compounds, 1, 3, 6-9, 12, and 13, were determined by means of CD studies. Fourteen compounds, 1-3 and 6-16, have been tested on a multidrug-resistant Leishmania tropica line overexpressing a P-glycoprotein-like transporter to determine their ability to revert the resistance phenotype and to modulate intracellular drug accumulation. From this series, 1, 2, 3, 14, and 15 showed potent activity, 1 being the most active compound. The structure-activity relationships of the different compounds are discussed.Peer Reviewe

Bis-pyranobenzoquinones as a new family of reversal agents of the multidrug resistance phenotype mediated by P-glycoprotein in mammalian cells and the protozoan parasite Leishmania

We have synthesized a set of bis-pyranobenzoquinones through a direct and highly efficient approach based on a double intramolecular domino Knoevenagel hetero Diels-Alder reaction. These bis-pyranobenzoquinone derivatives are compounds whose skeletons have similarities to those of some anticancerous and leishmanicidal drugs. Considering that these drugs are substrates for some members of the ATP-binding cassette (ABC) family of proteins that confers a multidrug resistance (MDR) phenotype, we have carried out the biological evaluation of 20 bis-pyranobenzoquinones as modulators of the MDR phenotype in mammalian cell lines overexpressing P-glycoprotein, MRP1, or BCRP. Moreover, we also tested some of these compounds as potential MDR modulators in a Leishmania tropica line overexpressing a P-glycoprotein-like transporter. Compounds 9 and 10 are, in this work, the most promising reversal agents of MDR in human cancer cell lines, while compounds 4 and 20 showed potent reversal activity of MDR phenotype in the protozoan parasite Leishmania. © 2008 American Chemical Society.Peer Reviewe

Application of the Permutation Entropy over the Heart Rate Variability for the Improvement of Electrocardiogram-based Sleep Breathing Pause Detection

In this paper the permutation entropy (PE) obtained from heart rate variability (HRV) is analyzed in a statistical model. In this model we also integrate other feature extraction techniques, the cepstrum coefficients derived from the same HRV and a set of band powers obtained from the electrocardiogram derived respiratory (EDR) signal. The aim of the model is detecting obstructive sleep apnea (OSA) events. For this purpose, we apply two statistical classification methods: Logistic Regression (LR) and Quadratic Discriminant Analysis (QDA). For testing the models we use seventy ECG recordings from the Physionet database which are divided into equal-size learning and testing sets. Both sets consist of 35 recordings, each containing a single ECG signal. In our experiments we have found that the features extracted from the EDR signal present a sensitivity of 65.6% and specificity of 87.7% (auc = 85) in the LR classifier, and sensitivity of 59.4% and specificity of 90.3% (auc = 83.9) in the QDA classifier. The HRV-based cepstrum coefficients present a sensitivity of 63.8% and specificity of 89.2% (auc = 86) in the LR classifier, and sensitivity of 67.2% and specificity of 86.8% (auc = 86.9) in the QDA. Subsequent tests show that the contribution of the permutation entropy increases the performance of the classifiers, implying that the complexity of RR interval time series play an important role in the breathing pauses detection. Particularly, when all features are jointly used, the quantification task reaches a sensitivity of 71.9% and specificity of 92.1% (auc = 90.3) for LR. Similarly, for QDA the sensitivity is 75.1% and the specificity is 90.5% (auc = 91.7)

Libs portable system for the determination of chemical elements present in the deterioration of patrimonial buildings

Stone materials, despite their great stability as construction materials, are not free from deterioration caused by nature, an effect that has been intensified by urban and industrial developments. Laser-induced breakdown spectroscopy (LIBS) is considered one of the most dynamic and promising techniques in the field of analytical spectroscopy. LIBS, which is performed in situ and is virtually non-destructive, offers a potential alternative to other techniques used in fields such as archaeology, preservation and restoration. In this work, the LIBS technique identifies key components and contaminants on the surface of the walls of the Convento y Basílica Menor de San Francisco de Asís, a historical building located in Old Havana, Cuba. The results are compared to previously performed analyses by X-ray fluorescence (XRF)