2,867 research outputs found
Landslide Hazard in El Salvador
The destructive seismic events of January 13 (ML: 7.6) and February 13 (ML: 6.1) 2001 in El Salvador, with origin in the subduction area and the volcanic chain, respectively, provide an ideal scenario to analyse the factors that define the landslide hazard in this country. In this paper we analysed the events in terms of strong-motion and precedent climatic condition and their relation with the landslides induced; establishing a great opportunity to compare some hazard assessment methods as those proposed by Mora and Vahrson (1994) and Rodríguez (2001) which define the hazard in terms of the interaction between triggering agents and susceptibility conditions.
Historically both rainfalls and earthquakes have shown to be important triggers for landslides in El Salvador, and results show how the combination of these factors are also critical in defining trigger thresholds and in controlling failure mechanisms. It was found that the Mora and Vahrson method underestimates the landslides hazard; as was discussed by Bommer and Rodríguez (2002), this is mainly due to the rainfalls levels used by the method which were defined for the Costa Rica conditions, which are markedly different to those in El Salvador. The Rodríguez model describes in a better way the landslides hazard, however in some areas the hazard is overestimated due to the way as weighting factors for lithology shades the influence of topography, this suggests that assignment of weighting values in the model must be reviewed implementing a multivariate correspondence analysis instead of the bivariate model used so far
SUR1 Receptor Interaction with Hesperidin and Linarin Predicts Possible Mechanisms of Action of Valeriana officinalis in Parkinson.
Parkinson's disease (PD) is one of the most common neurodegenerative disorders. A theoretical approach of our previous experiments reporting the cytoprotective effects of the Valeriana officinalis compounds extract for PD is suggested. In addiction to considering the PD as a result of mitochondrial metabolic imbalance and oxidative stress, such as in our previous in vitro model of rotenone, in the present manuscript we added a genomic approach to evaluate the possible underlying mechanisms of the effect of the plant extract. Microarray of substantia nigra (SN) genome obtained from Allen Brain Institute was analyzed using gene set enrichment analysis to build a network of hub genes implicated in PD. Proteins transcribed from hub genes and their ligands selected by search ensemble approach algorithm were subjected to molecular docking studies, as well as 20 ns Molecular Dynamics (MD) using a Molecular Mechanic Poison/Boltzman Surface Area (MMPBSA) protocol. Our results bring a new approach to Valeriana officinalis extract, and suggest that hesperidin, and probably linarin are able to relieve effects of oxidative stress during ATP depletion due to its ability to binding SUR1. In addition, the key role of valerenic acid and apigenin is possibly related to prevent cortical hyperexcitation by inducing neuronal cells from SN to release GABA on brain stem. Thus, under hyperexcitability, oxidative stress, asphyxia and/or ATP depletion, Valeriana officinalis may trigger different mechanisms to provide neuronal cell protection.Fil: Santos, Gesivaldo. Universidade Estadual do Sudoeste da Bahia; BrasilFil: Giraldez Alvarez, Lisandro Diego. Universidade Estadual do Sudoeste da Bahia; BrasilFil: Ávila Rodriguez, Marco. Pontificia Universidad Javeriana; ColombiaFil: Capani, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Galembeck, Eduardo. Universidade Estadual de Campinas; BrasilFil: Gôes Neto, Aristóteles. Universidade Estadual de Feira de Santana; BrasilFil: Barreto, George E.. Pontificia Universidad Javeriana; ColombiaFil: Andrade, Bruno. Universidade Estadual do Sudoeste da Bahia; Brasi
Eocene decapod crustacea (thalassinidea and brachyura) from Patagonia, Argentina
Rocks of the Rio Turbio Formation, exposed in southern Patagonia, Argentina, represent one of very few occurrences of Eocene rocks in the region. Decapod crustaceans collected from the unit include one species of thalassinidean mud shrimp; Turbiocheir minutospinata, new genus, new species; and three species of brachyurans; Raninoides rioturbiensis, new species; Megokkos patagoniensis, new species; and Nitotacarcinus antipodes, new species. The three brachyuran genera are also known from species in the Northeast Pacific, suggesting an amphitropical distributional pattern.Fil: Schweitzer, Carrie E.. Kent State University; Estados UnidosFil: Feldmann, Rodney M.. Kent State University; Estados UnidosFil: Casadio, Silvio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Rodriguez Raising, Martin Eduardo. Universidad Nacional de La Pampa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Redox and Catalytic Properties of Promoted NiO Catalysts for the Oxidative Dehydrogenation of Ethane
[EN] NiO and metal-promoted NiO catalysts (M-NiO, with a M/(M+Ni) atomic ratio of 0.08, with M = Nb, Sn, or La) have been prepared, tested in the oxidative dehydrogenation (ODH) of ethane, and characterized by means of XRD, TPR, HRTEM, Raman, XPS, and in situ XAS (using H-2/He, air or C2H6/He mixtures). The selectivity to ethylene during the ODH of ethane decreases according to the following trend: Nb NiO Sn NiO > La NiO > NiO, whereas the catalyst reducibility (determined by both TPR and XAS using H-2/He mixtures) shows the opposite trend. However, different reducibility and catalytic behavior in the absence of oxygen (ethane/He mixtures) have been observed, especially when comparing Nb- and Sn-promoted NiO samples. These differences can be ascribed mainly to a different phase distribution of the promoter. The results presented here are discussed in terms of the nature of active and selective sites for ODH of ethane in selective and unselective catalysts, but also the role of promoters and the importance of their phase distribution.The authors would like to acknowledge the DGICYT in Spain CTQ2012-37925-C03-2, CTQ2015-68951-C3-1-R, and CTQ2015-68951-C3-3-R. Authors thank European Synchrotron Radiation Facility, ESRF (Project CH-4512; BM25-SpLine Beamlime). Authors from ITQ also thank Project SEV-2016-0683 for financial support. D.D. thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). B.S. also thanks UV-INV-AE16-484416. Finally, the authors thank the Electron Microscopy Service of Universitat Politecnica de Valencia for their support.Delgado-Muñoz, D.; Solsona Espriu, BE.; Ykrelef, A.; Rodriguez-Gomez, A.; Caballero, A.; Rodríguez-Aguado, E.; Rodriguez-Castellón, E.... (2017). Redox and Catalytic Properties of Promoted NiO Catalysts for the Oxidative Dehydrogenation of Ethane. The Journal of Physical Chemistry C. 121(45):25132-25142. https://doi.org/10.1021/acs.jpcc.7b07066S25132251421214
Online Applied Problem-Based Learning to Determine the Shelf Life of an on-Site Solution of Refrigerated Drug
A problem-based online learning (PBe-L) teaching sequence was designed for calculating the shelf life (expiration date) of an on-site solution of refrigerated drug as part of activities of a Pharmaceutical Physical Chemistry course of Pharmacy major at FES Cuautitlán UNAM in Mexico. The teacher presents students the problem, a group collaborative activity is carried out to search for information in PBL cycles. Students are then shown a virtual experiment that includes experimental results. Another group collaborative activity is carried out for the search of information, for the procedural analysis of the results. Applying knowledge and understanding of the topics of chemical kinetics, temperature effect on the rate of chemical reactions and drug degradation reactions, etc., students solve the problem. Hake's factor was determined for the conceptual gain. A Likert-type satisfaction survey was conducted and compared to the results of a group that was applied to the PBL strategy in person. At the end of the sequence students achieved recognition, comprehension and application learnings and conceptual gain was high. Allowing an integration of its cognitive framework of kinetics topics
Chronic myocardial infarction detection and characterization during coronary artery calcium scoring acquisitions
Background: Hypoenhanced regions on multidetector CT (MDCT) coronary angiography correlate with myocardial hyperperfusion. In addition to a limited capillary density, chronic myocardial infarction (MI) commonly contains a considerable amount of adipose tissue. Objective: We explored whether regional myocardial hypoenhancement on contrast-enhanced MDCT could be identified with standard coronary artery calcium (CAC) scoring acquisitions with noncontrast CT. Methods: Consecutive patients with a history of MI who were referred for contrast-enhanced MDCT from November 2006 until March 2009 were studied. Noncontrast CT for CAC scoring was also performed. The correlation between regional myocardial hypoenhancement on contrast-enhanced CT and regional myocardial hypoattenuated areas on noncontrast CT was defined. Results: Eighty-three patients (mean age, 61.5 ± 12.5 years; n = 67; 81% male) with previous MI were studied. A total of 1411 myocardial segments were evaluated. Two hundred thirty-nine segments (17%) showed myocardial hypoenhancement by MDCT and 140 segments (9.6%) by CAC. On a patient level, noncontrast CT showed a sensitivity, specificity, positive predictive value, (PPV) and negative predictive value (NPV) of 66% (95% CI, 0.53-0.77), 100% (95% CI, 0.76-1.00), 100% (95% CI, 0.90-1.00), and 41% (95% CI, 0.26-0.58), respectively, to detect myocardial hypoenhancement. On a per segment level, noncontrast CT showed a sensitivity, specificity, PPV, and NPV of 58% (95% CI, 0.51-0.64), 100% (95% CI, 0.99-1.00), 99% (95% CI, 0.94-1.00), and 92% (95% CI, 0.90-0.93), respectively, to detect myocardial hypoenhancement. Conclusions: Our findings suggest that chronic MI can be detected with standard CAC scoring acquisitions. © 2010 Society of Cardiovascular Computed Tomography.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Rosales, Miguel A.. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Renes, Paola. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Diez, Eduardo. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Pereyra, Jorge. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Gomez, Estela. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: De Lillo, Gustavo. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Degrossi, Elina. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: Rodriguez, Alfredo E.. Sanatorio "Otamendi y Miroli S. A."; ArgentinaFil: McFadden, Eugene P.. Cork University Hospital; Irland
Altered expression and activation of signal transducers and activators of transcription (STATs) in hepatitis C virus infection: in vivo and in vitro studies
BACKGROUND: Signal transducers and activators of transcription (STATs) play a critical role in antiviral defence. STAT3 is also important in cell protection against inflammatory damage. STAT proteins are activated by interferons and by hepatoprotective cytokines of the interleukin 6 superfamily, including cardiotrophin 1.
METHODS: We analysed the status of STATs in hepatitis C virus (HCV) infected livers and the relationship between expression and activation of STATs and HCV replication in Huh7 cells transfected with HCV genomic replicon.
RESULTS: STAT3alpha expression was reduced in HCV infected livers showing an inverse correlation with serum alanine aminotransferase. In patients with HCV infection, nuclear staining for phosphorylated STAT3 was faint in parenchymal cells (although conspicuous in infiltrating leucocytes), in contrast with strong nuclear staining in hepatocytes from control livers. Expression and activation of STAT1 (a factor activated by both interferon (IFN)-alpha and IFN-gamma) were increased in HCV infected livers, particularly in those with high inflammatory activity. Conversely, phosphorylated STAT2 (a factor selectively activated by IFN-alpha) was undetectable in livers with HCV infection, a finding that was associated with marked downregulation of the two functional subunits of the IFN-alpha receptor. HCV replication in Huh7 cells caused STAT3alpha downregulation and blocked STAT3 phosphorylation by either IFN-alpha or cardiotrophin 1. HCV replication in Huh7 cells also inhibited STAT1 and STAT2 activation by IFN-alpha while there was no impairment of STAT1 phosphorylation by the proinflammatory cytokine IFN-gamma.
CONCLUSIONS: STAT3 is downregulated in HCV infected livers and in Huh7 cells bearing the full length HCV replicon. HCV replication is associated with impaired Jak-STAT signalling by antiviral and cytoprotective cytokines. These effects may favour viral replication while facilitating the progression of liver diseas
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