2,343 research outputs found

    An approach to the natural and engineered nanoparticles analysis in the environment by inductively coupled plasma mass spectrometry

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    Different approaches to the most relevant and recent studies and applications of inductively coupled plasma mass spectrometry (ICP-MS) applied to the analysis of natural and engineered nanoparticles in the environment are described. Usually several separation methods like polyacrylamide gel electrophoresis (PAGE), field-flow fractionation (FFF) and size exclusion chromatography (SEC) are used prior to the mass spectrometric measurements. In many cases the use of these hyphenated techniques provides important methodologies to know the bioavailability, mobility and toxicity of elements in life and environmental sciences. Alternatively, the capabilities of the single particle detection by ICP-MS (SD-ICP-MS) for the selective identification, characterization and determination of engineered nanoparticles will be also discussed

    Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples

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    The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for dealing with complex samples. Single- and multi-method approaches applied to solve the nanometrological challenges posed by a variety of stakeholders are also presented

    Minimal spontaneously broken hidden sector and its impact on Higgs boson physics at the Large Hadron Collider

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    We have studied a hidden sector of the SM with spontaneous symmetry breaking that opens many different scenarios for Higgs physics. We have shown that this hidden sector can affect the SM Higgs detection. In some speci c regimes it is still possible to detect the Higgs; in other scenarios the hidden sector would completely eclipse it

    A longitudinal study on perceived health in cardiovascular patients. The role of conscientiousness, subjective wellbeing and cardiac self-efficacy

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    Cardiovascular disease (CVD) is the world’s most prevalent chronic disease and the leading chronic cause of morbidity. There are several psychosocial factors associated with quality of life during CVD. Our main objectives were to analyze the roles of conscientiousness, subjective wellbeing and self-efficacy beliefs. The sample comprised 514 patients (mean age 63.57 years) who were assessed twice over a nine-month interval. At Time 1, participants answered a questionnaire assessing conscientiousness, perceived subjective wellbeing (positive and negative affect, life satisfaction), cardiac self-efficacy and health-related quality of life (HRQoL). The same variables (except for conscientiousness) were re-assessed at Time 2. Results showed that conscientiousness had a positive relation with subjective wellbeing, cardiac self-efficacy, and HRQoL at Time 1. Moreover, cardiac self-efficacy at Time 1 had a positive longitudinal effect on HRQoL at Time 2, while controlling for autoregressive effects. Mediation analyses indicated that the relationship between conscientiousness and HRQoL was mediated by positive affect and cardiac self-efficacy. These results suggest the usefulness of psychosocial interventions aimed at promoting positive affect and self-efficacy beliefs among CVD patients

    Genetic diversity of Huaya India (\u3ci\u3eMelicoccus oliviformis\u3c/i\u3e Kunth), a neglected Neotropical fruit crop

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    Currently, some species of Sapindaceae are important fruit crops worldwide. The Huaya India (Meliccocus oliviformis, Sapindaceae) is a neglected Neotropical fruit tree consumed locally in the Maya Lowlands of Mexico, where it exists in both wild and domesticated forms. Our objective was to evaluate the genetic diversity of the Huaya India in its possible domestication area and thus generate knowledge that serves as the basis for a commercial management. A total of 450 individuals collected from 15 natural vegetation sites and 15 Maya villages, were characterized using nine microsatellite loci and population genetics approaches were applied. STRUCTURE, Neighbor-Joining and PCoA analyses suggested the existence of three main groups: 1) one composed by 14 natural vegetation sites, 2) one integrated by 10 Maya villages plus one natural vegetation site, 3) one composed by five Maya villages. At the species level, genetic differentiation was high (FST = 0.562) and gene flow was low (Nm = 0.395); between genetic groups, differentiation was low and gene flow was high. Genetic diversity was low at the level species (HE = 0.19) and higher in the group composed for only natural vegetation sites. When we considered only two groups (natural vegetation sites vs Maya villages) to explore a possible bottleneck as a consequence of human management, the natural vegetation sites showed higher, and significant, genetic diversity (HE = 0.231) than the Maya villages (HE = 0.152). This study can serve as a basis to develop management strategies for Huaya India in the Maya Lowlands of Mexico, but without compromising its conservation

    Asymmetrical structure of ionization and kinematics in the Seyfert galaxy NGC 5033

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    We present integral field spectroscopy of NGC 5033, a low luminosity Seyfert galaxy. The observations were made with INTEGRAL, a fiber based system operating at the WHT. The intensity map of the Hβ\beta emission line represents a spiral or ring-like pattern of HII regions. On the contrary, the [OIII] intensity map morphology is markedly anisotropic. The strong morphological differences imply that the [OIII] emitters represent highly ionized gas illuminated by the central source. The [OIII] map morphology is compatible with a biconical structure of ionization induced by strong extinction in the galaxy disc that also obscures half of the spheroidal stellar bulge. We identify the spectrum corresponding to the Seyfert 1 nucleus from the presence of Hβ\beta broad emission lines. This spectrum is located in a region where strong extinction is expected but exhibits the bluest spectral energy distribution. The Seyfert 1 nucleus seems to be offcenter with respect to the stellar rotation center. This result has been also found in other Seyfert galaxies and interpreted in terms of a past merger. The offcentering could indicate the presence of nonsymmetric departures in the gravitational potential which could be fueling the active nucleus. The kinematics of the [OIII] emitters show important deviations at a kpc scale with respect to the stellar velocity field and show features related to the asymmetrical morphology of the high ionization region.Comment: 9 pages, accepted for publication in Astronomy and Astrophysics. Figures 1 and 7 are attached as .gif file

    ¿Se asocia el consumo de refrescos azucarados con la composición corporal? Estudio transversal en adolescentes españoles

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    Objectives: Published data about the association between the consumption of sweetened soft-drinks (SSD) and obesity in childhood are controversial and still inconsistent. In addition, data are lacking in the Spanish population. The purpose of this study was therefore, to explore the cross-sectional association between body composition- related parameters and SSD consumption in Spanish adolescents. Subjects and methods: A representative sample of 1,523 adolescents (768 boys and 755 girls), with complete dietary data as well as anthropometric measurements, were included in this study. Weight, height, waist circumferences, and 6 skinfolds were measured, and BMI and percentage body fat were calculated. From a 24h dietary recall the subjects were grouped in 3 groups according to their SSD consumption: 1) Non-consumers (0 g of SSD consumption); 2) Moderate consumption (< 336 g/day of SSD, equivalent to the average SSD portion size); and 3) High consumption (> 336 g/day of SSD). Results: 67% males and 75% females did not consume any SSD the day before the dietary recall interview. Males consumed more SSD than females. Regarding the association between SSD consumption and measures of obesity, no difference was observed between the three groups of SSD consumption in any of the anthropometric measurement, BMI or body fat. Conclusion: As no association was present between SSD consumption and obesity in our cross-sectional study we suggest that dietary patterns and habits as well as lifestyle factors such as physical activity should be present when examining cross-sectional or longitudinal relationships with obesity. Multidisciplinary intervention studies are crucial when trying to develop solutions against the increasing obesity epidemic.Objetivos: Los datos publicados sobre la asociación entre el consumo de refrescos azucarados (SSD) y la obesidad en la infancia son controvertidos y todavía inconsistentes. Además, estos datos son muy escasos en la población española. Por ello, el propósito de este estudio ha sido estudiar la asociación entre los parámetros relacionados con la composición corporal y el consumo de SSD en adolescentes españoles. Sujetos y métodos: Se ha realizado el estudio en una muestra de 1.523 adolescentes (768 chicos y 755 chicas) que tenían cumplimentados los datos dietéticos y los parámetros antropométricos (peso, altura, circunferencias de cintura, y 6 pliegues). Se calculó el IMC y el porcentaje de grasa corporal. La dieta ha sido calculada a partir de un recordatorio de 24h. Los sujetos fueron divididos en grupos dependiendo de la cantidad de SSD que consumían: 1) No consumidores (0 g de consumo SSD); 2) Consumo moderado (< 336 g/día de SSD, equivalente a una bebida al día de SSD); y 3) Consumo alto (> 336 g/día de SSD). Resultados: El 67% de los varones y el 75% de las mujeres indican no consumir este tipo de bebidas el día anterior a la encuesta. Los varones en general consumieron más SSD que las mujeres. En cuanto a la asociación entre consumo SSD y medidas antropométricas y de composición corporal, no se encontraron diferencias significativas entre los tres grupos de estudio en los parámetros antropométricos, IMC o grasa corporal. Conclusión: Dado que no se ha encontrado en este estudio ninguna asociación entre el consumo de SSD y la obesidad, sugerimos que los patrones y hábitos dietarios así como los factores del estilo de vida, y la actividad física, deberían tenerse en cuenta al examinar las relaciones transversales o longitudinales con la obesidad, y que los estudios de intervención multidisciplinar son cruciales cuando se trata de desarrollar soluciones contra el incremento de una epidemia como la obesidad.The AVENA study was supported by Spanish Ministry of Health (00/0015) and by grants from the Spanish Higher Sports Council (05/UPB32/01, 09/UPB31/03 and 13/UPB20/04), the Spanish Ministry of Education (AP2003-2128 and AP2004-2745), Coca-Cola, Panrico SA, Madaus SA and Procter & Gamble SA

    Nicotianamine Synthase 2 Is Required for Symbiotic Nitrogen Fixation in Medicago truncatula Nodules

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    Symbiotic nitrogen fixation carried out by the interaction between legumes and diazotrophic bacteria known as rhizobia requires relatively large levels of transition metals. These elements are cofactors of many key enzymes involved in this process. Metallic micronutrients are obtained from soil by the roots and directed to sink organs by the vasculature, in a process mediated by a number of metal transporters and small organic molecules that facilitate metal delivery in the plant fluids. Among the later, nicotianamine is one of the most important. Synthesized by nicotianamine synthases (NAS), this molecule forms metal complexes participating in intracellular metal homeostasis and long-distance metal trafficking. Here we characterized the NAS2 gene from model legume Medicago truncatula. MtNAS2 is located in the root vasculature and in all nodule tissues in the infection and fixation zones. Symbiotic nitrogen fixation requires of MtNAS2 function, as indicated by the loss of nitrogenase activity in the insertional mutant nas2-1, phenotype reverted by reintroduction of a wild-type copy of MtNAS2. This would result from the altered iron distribution in nas2-1 nodules shown with X-ray fluorescence. Moreover, iron speciation is also affected in these nodules. These data suggest a role of nicotianamine in iron delivery for symbiotic nitrogen fixation

    Clinical case of a patient undergoing radium-223 treatment following treatment with abiraterone acetate and enzalutamide

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    Objective: Over the last decade, significant advances have been made in the development of therapies for patients with metastatic castration-resistant prostate cancer. Abiraterone and enzalutamide were approved as treatments based on data supporting improved overall survival compared to placebo. Radium-223 became the first approved radiopharmaceutical which decreased skeletal-related events, palliated pain, and showed improved overall survival in symptomatic patients with castration-resistant prostate cancer and bone metastasis only. Materials and Methods: We present the case of an eighty-two year old man with metastatic castration-resistant prostate cancer who was treated with sequential therapy (abiraterone — enzalutamide — radium-223). The sequencing and treatment used for our patient was viable because of his clinical characteristics, which have allowed for longer survival time with an acceptable quality of life. These actions must be agreed on by the Multidisciplinary Tumour Board, in order to optimize the use of available courses of treatment. Results: The treatment of these patients is changing rapidly, but many questions remain regarding the optimal sequencing of the available drugs. Sequential or concomitant use of the next generation hormonal agents — abiraterone and enzalutamide — cannot currently be recommended. Data regarding the safety of concomitant abiraterone, enzalutamide or denosumab with radium-223 is reassuring and timely. However, we cannot advocate the general use of combined radium-223 therapy at this time, irrespective of prior therapy. Conclusion: A better understanding of active mechanisms, the genetic characteristics of each metastatic castration-resistant prostate cancer and the development of new prognostic and predictive biomarkers will help determine sequencing or different combination treatments for each individual patient. Key Words: castration-resistant prostate cancer, treatment sequence, abiraterone acetate, enzalutamide, radiopharmaceutic
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