2,579 research outputs found
Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry
A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg
The Current State of Knowledge of Hepatic Ischemia-Reperfusion Injury Based on Its Study in Experimental Models
The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R) injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered
The role of family in the intergenerational transmission of collective action
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThe present research demonstrates intergenerational influences on collective action participation, whereby parents’ past and current participation in collective action (descriptive family norms) shape their children’s participation in conventional and radical collective action via injunctive family norms (perception that parents value such participation). Two unique data sets were used: dyads of activist parents and their adult children (Study 1, N = 100 dyads) and student activists who participated in a yearlong, three-wave longitudinal study (Study 2, Ns wave 1 = 1,221, Wave 2 = 960, and Wave 3 = 917). Parents’ past and current participation directly and indirectly predicted children’s protest participation in Study 1, while Study 2 showed a similar pattern longitudinally: Perceptions of parents’ participation (descriptive family norm) and approval (injunctive family norm) predicted change in collective action participation over time. Together, results highlight family environment as a critical setting for the intergenerational transmission of protest
Determination of Arsenic, Mercury and Barium in Herbarium Mount Paper using 5 Dynamic Ultrasound-Assisted Extraction prior to Atomic Fluorescence and Absorption 6 Spectrometries 7 8
Abstract 25 A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic 26 Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and 27 barium from herbarium mount paper originating from the herbarium collection of the 28 National Museum of Wales. The variables influencing extraction were optimised by a 29 multivariate approach. The optimal conditions were found to be 1% HNO 3 extractant solution 30 used at a flow rate of 1 mL min -1 . The duty cycle and amplitude of the ultrasonic probe was 31 found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance 32 between the probe and the top face of the extraction chamber was found to be 0 cm. Under 33 these conditions the time required for complete extraction of the three analytes was 25 min. 34 2 Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was 1 utilized to determine mercury and arsenic, respectively. The chemical and instrumental 2 conditions were optimized to provide detection limits of 0.01ng g -1 and 1.25 ng g -1 for 3 mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic 4 absorption spectrometry, with a detection limit of 25 ng g -1 . By using 0.5 g of sample, the 5 concentrations of the target analytes varied for the different types of paper and ranged 6 between 0.4-2.55 µg g -1 for Ba, 0.035-10.47 µg g -1 for As and 0.0046-2.37 µg g -1 for Hg. 7 8
Encephalopathies Associated With Severe COVID-19 Present Neurovascular Unit Alterations Without Evidence for Strong Neuroinflammation.
Coronavirus disease (COVID-19) has been associated with a large variety of neurologic disorders. However, the mechanisms underlying these neurologic complications remain elusive. In this study, we aimed at determining whether neurologic symptoms were caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) direct infection or by either systemic or local proinflammatory mediators.
In this cross-sectional study, we checked for SARS-CoV-2 RNA by quantitative reverse transcription PCR, SARS-CoV-2-specific antibodies, and 49 cytokines/chemokines/growth factors (by Luminex) in the CSF +/- sera of a cohort of 22 COVID-19 patients with neurologic presentation and 55 neurologic control patients (inflammatory neurologic disorder [IND], noninflammatory neurologic disorder, and MS).
We detected anti-SARS-CoV-2 immunoglobulin G in patients with severe COVID-19 with signs of intrathecal synthesis for some of them. Of the 4 categories of tested patients, the CSF of IND exhibited the highest level of cytokines, chemokines, and growth factors. By contrast, patients with COVID-19 did not present overall upregulation of inflammatory mediators in the CSF. However, patients with severe COVID-19 (intensive care unit patients) exhibited higher concentrations of CCL2, CXCL8, and vascular endothelium growth factor A (VEGF-A) in the CSF than patients with a milder form of COVID-19. In addition, we could show that intrathecal CXCL8 synthesis was linked to an elevated albumin ratio and correlated with the increase of peripheral inflammation (serum hepatocyte growth factor [HGF] and CXCL10).
Our results do not indicate active replication of SARS-CoV-2 in the CSF or signs of massive inflammation in the CSF compartment but highlight a specific impairment of the neurovascular unit linked to intrathecal production of CXCL8
Correlación en triatlón masculino entre fases y resultado inal en los JJOO de Pekin 2008
Introduction: Triathlon is a sport that is composed of the combination of three phases of competition. The most widespread triathlon is the Olympic, and is used in the Olympic Games, consists of swim, 1.5 km, bike 40 km and run 10 km. Aims: To determine the influence of the duration and order of the phases with the final result of the test in the male triathlon in the Olympic Games Beijing 2008. Method: We analyzed the data of 50 athletes who finished. Results and conclusions: The final result is not determined by the order of the phases, nor by the duration of these, the least influential phase has been Bike with rs = .039; p = .351; Being the one that has occupied the most time with 52.55%; The most influential phase was the Run phase with rs = .991; and p = .000; and R2 = .982 and with duration 30.21%.Introducción: El triatlón es un deporte que se compone de la combinación de tres fases de competición. La modalidad de triatlón más extendida es la olímpica, y es utilizada en los Juegos Olímpicos (JJOO), se compone de nado 1,5 km, bicicleta 40 km y carrera 10 km. Objetivos: Determinar la influencia de la duración y orden de las fases con el resultado final de la prueba en el triatlón masculino en los JJOO Pekín 2008. Método: Se analizaron los datos de 50 deportistas que finalizaron. Resultados y conclusiones: El resultado final no viene determinado ni por el orden de las fases, ni por la duración de estas, la fase menos influyente ha sido Bike con rs= 0,039; p =0,351; siendo la que más tiempo ha ocupado con un 52,55%; la fase más influyente ha sido la fase Run con rs=0,991; y p=0,000; y R2=0,982 y con duración 30,21%
The intergenerational transmission of participation in collective action: The role of conversation and political practices in the family
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordIn this study, we examined the intergenerational transmission of collective action from parents to children. Using a mixed-method approach combining quantitative and qualitative analysis, we analysed data from 100 dyads of activist parents in Chile (involved in the mobilizations against the dictatorship during the 1980s) and their adult children (N = 200). The quantitative analysis addressed the role of conversations about politics in the family. The results provided evidence of a direct association between those conversations and the frequency of participation in conventional and radical actions by the children, and an indirect association via children’s knowledge about parental involvement in past social movements. The qualitative phase, which used interviews and thematic analysis on a subsample of 24 dyads (N = 48), confirmed the role of political conversations, but also revealed the influence of other factors such as cultural consumption and joint political participation. This phase allowed the identification of factors that facilitate or hinder family transmission. Overall, the study highlights the relevance of family as a critical site of socialization that enables the intergenerational transmission of protest.Chilean National Foundation for Scientific and Technological DevelopmentCenter for Social Conflict and Cohesion StudiesInterdisciplinary Center for Intercultural and Indigenous Studie
Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and
Technology (CICYT), the
Spanish National Parks agency, the European Commission, the
Spanish Ministry of Science, and the European
Social Fund
Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and
Technology (CICYT), the
Spanish National Parks agency, the European Commission, the
Spanish Ministry of Science, and the European
Social Fund
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