2,404 research outputs found
An approach to the natural and engineered nanoparticles analysis in the environment by inductively coupled plasma mass spectrometry
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
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
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
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
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
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 H 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 H 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
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
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
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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