Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that tend to rapidly associate to particulate organic matter in sediments due to their hydrophobic characteristics, inducing toxic, ...carcinogens and mutagens effects to many living organisms. The monitoring and identification of the sources of PAHs in sediments is relevant especially because they are the main reservoir and secondary source of contamination of aquatic systems. To identify the sources there are different methods for data treatment that complement each other: evaluation of profiles distribution, source-specific diagnostic ratios of PAHs and principal component analysis (PCA). To demonstrate the applicability of these different methods, concentrations of PAHs from sediments of four Portuguese estuarine systems were used: Ria de Aveiro, Tagus River, Sado River and Ria Formosa, in order to identify the sources.
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•PAHs sources in river sediments were identified by different approaches.•The highest PAHs concentration was found in Tagus river.•The main source of PAHs is pyrogenic.•Other origins of PAHs are notorious: petrogenic and petroleum combustion.
There is mounting evidence that family functioning is linked to childhood overweight and obesity, and that both of these are associated with health-related behaviours and adverse health outcomes in ...children and adolescents. This paper systematically examines the peer-reviewed evidence regarding the relationship between child and adolescent overweight and obesity and family functioning. Peer-reviewed literature published between 1990 and 2011 hosted in Scopus, Pub Med or Psyc INFO were searched, in addition to the reference lists of included papers. Twenty-one studies met the selection criteria. Of the 17 identified cross-sectional and longitudinal studies, 12 reported significant associations between family functioning and childhood overweight and obesity. The instruments used to measure family functioning in the identified studies were heterogeneous. Poor family functioning was associated with increased risk of obesity and overweight in children and adolescents, and obese children and adolescents were more likely to come from families with poor family functioning. Aspects of family functioning which were associated with increased risk of child and adolescent obesity included poor communication, poor behaviour control, high levels of family conflict and low family hierarchy values. Half (2/4) of the identified intervention studies showed a significant relationship between family functioning and changes in child weight. The results demonstrate that family functioning is linked to obesity; however, higher level evidence and greater understanding of the mechanisms behind this relationship are required. The results indicate a need for a standardised family functioning measure applicable across populations. The results provide evidence of the value of considering family functioning in childhood obesity research and intervention.
The South American continent is composed of several biogeographical regions harbouring the highest biodiversity on the globe, encompassing five of the world's biodiversity ‘hot spots’. Nonetheless, ...the patterns and processes responsible for shaping its astonishing species diversity are largely unknown. Here, we present a review of current South American phylogeographical knowledge based on published articles on this topic. An appraisal of the literature reveals emerging phylogeographical patterns in the biota of South America. The striking phylogeographical divergence observed among organism lineages in South American studies is suggestive of high levels of undocumented species diversity. The interplay between Pleistocene climatic oscillations and Pliocene/Miocene orogenic events has contributed to shaping the current diversity and distribution of modern lineages in both the tropical and temperate regions of South America. Although older divergence times were observed for a range of species, most herpetofauna underwent an intraspecific lineage split much earlier than other organisms. The geographical ranges of species associated with forest habitats were reduced mainly during glacial cycles, whereas species associated with open vegetation domains have shown variable responses to climatic oscillations. The results suggest a highly complex mosaic of phylogeographical patterns in South America. We suggest future research directions to promote a better understanding of the origin and maintenance of the South American biota.
Abstract
Metal-insulator-semiconductor (MIS) structures are widely used in Si-based solar water-splitting photoelectrodes to protect the Si layer from corrosion. Typically, there is a tradeoff ...between efficiency and stability when optimizing insulator thickness. Moreover, lithographic patterning is often required for fabricating MIS photoelectrodes. In this study, we demonstrate improved Si-based MIS photoanodes with thick insulating layers fabricated using thin-film reactions to create localized conduction paths through the insulator and electrodeposition to form metal catalyst islands. These fabrication approaches are low-cost and highly scalable, and yield MIS photoanodes with low onset potential, high saturation current density, and excellent stability. By combining this approach with a p
+
n-Si buried junction, further improved oxygen evolution reaction (OER) performance is achieved with an onset potential of 0.7 V versus reversible hydrogen electrode (RHE) and saturation current density of 32 mA/cm
2
under simulated AM1.5G illumination. Moreover, in stability testing in 1 M KOH aqueous solution, a constant photocurrent density of ~22 mA/cm
2
is maintained at 1.3 V versus RHE for 7 days.
•A micro-solid phase extraction device for portable liquid chromatography is shown.•The device uses 10 mg of C18 sorbent immobilized on a modified syringe filter.•Samples are processed manually ...without prior treatment.•Desorption and injection are performed in one step and in-port.•The device has been tested for different organic pollutants in environmental waters.
A micro-solid phase extraction (micro-SPE) device packed with a C18 sorbent (10 mg) has been developed for the enrichment and purification of organic water pollutants prior to their analysis using a portable liquid chromatograph with a dual UV detector. To this end, the sorbent was immobilized at the inlet of a 4 mm syringe filter (0.20 µm), which was modified to reduce its internal volume. The filter was coupled to the needle of the chromatograph. After loading the sample and cleaning the sorbent for analyte purification, the device was installed into the injection port of the chromatograph, and the target compounds were desorbed and transferred directly to the chromatographic column with a small volume of organic solvent. Under optimized conditions, sample volumes as large as 50 mL could be processed with the micro-SPE device, while the analytes were desorbed with only 60 µL of methanol. As a result, efficient preconcentration could be reached, as demonstrated for different water contaminants, namely aclonifen, bifenox, tritosulfuron, triflusulfuron-methyl and caffeine. The proposed micro-SPE device was applied to the analysis of different types of water (river, well, sea, ditch and wastewater). The recoveries of the target compounds in samples ranged from 76 % to 109 %, which allowed their detection at low to sub µg/L levels. All operations were carried out manually, and thus, no additional laboratory instruments such as centrifuges, stirrers or evaporators were required. This proof-of-concept study shows that the proposed micro-SPE approach can be considered a reliable and effective option for the on-site analysis of pollutants in environmental water samples by portable liquid chromatography.
Impact of Diabetes on Cardiovascular Disease: An Update Matheus, Alessandra Saldanha de Mattos; Tannus, Lucianne Righeti Monteiro; Cobas, Roberta Arnoldi ...
International Journal of Hypertension,
01/2013, Letnik:
2013
Journal Article
Recenzirano
Odprti dostop
Cardiovascular diseases are the most prevalent cause of morbidity and mortality among patients with type 1 or type 2 diabetes. The proposed mechanisms that can link accelerated atherosclerosis and ...increased cardiovascular risk in this population are poorly understood. It has been suggested that an association between hyperglycemia and intracellular metabolic changes can result in oxidative stress, low-grade inflammation, and endothelial dysfunction. Recently, epigenetic factors by different types of reactions are known to be responsible for the interaction between genes and environment and for this reason can also account for the association between diabetes and cardiovascular disease. The impact of clinical factors that may coexist with diabetes such as obesity, dyslipidemia, and hypertension are also discussed. Furthermore, evidence that justify screening for subclinical atherosclerosis in asymptomatic patients is controversial and is also matter of this review. The purpose of this paper is to describe the association between poor glycemic control, oxidative stress, markers of insulin resistance, and of low-grade inflammation that have been suggested as putative factors linking diabetes and cardiovascular disease.
The depopulation of rural areas in Spain, a phenomenon that has given rise to what is currently known as ‘empty Spain’, has become a serious social problem. The mass exodus of the young to the ...country's cities poses the main threat to rural sustainability. In this paper, at attempt is made to determine the factors that prompt the young to leave the Celtiberian Highlands, one of the most sparsely populated areas in Southern Europe, and the socio-educational measures that could be taken to avoid this exodus. To this end, a mixed-method approach with a sequential design was employed, in which members of the region's Rural Development Groups were administered a questionnaire and interviewed, whose findings were supplemented by in-situ observations. The young people living in the Celtiberian Highlands are currently facing a series of professional, social and personal challenges that encourage them to emigrate. A worrying feeling of rootlessness and inferiority with respect to urbanites was detected among them. In light of this, it is essential to adopt socio-educational measures that contribute to strengthen their ties to the rural community and to raise their awareness about the serious problems to which depopulation gives rise and the role that they could play to prevent it.
•There are few studies of the exodus of rural youth focusing on the most underpopulated area in Southern Europe.•The results suggest that fostering a feeling of belonging among the young to the community go to preventing their exodus.•A feeling of inferiority among rural youth with respect to urbanites has an influence on them when deciding to emigrate.•Rural youth should be made aware of the job and entrepreneurial opportunities open to them in their villages.
Relative humidity (RH) is a common interferent in chemical gas sensors, influencing their baselines and sensitivity, which can limit the performance of e-nose systems. Tuning the composition of the ...sensing materials is a possible strategy to control the impact of RH in gas sensors. Hybrid gel materials used as gas sensors contain self-assembled droplets of ionic liquid and liquid crystal molecules encapsulated in a polymeric matrix. In this work, we assessed the effect of the matrix hydrophobic properties in the performance of hybrid gel materials for VOC sensing in humid conditions (50% RH). We used two different polymers, the hydrophobic PDMS and the hydrophilic bovine gelatin, as polymeric matrices in hybrid gel materials containing imidazolium-based ionic liquids, BMIMCl and BMIMDCA, and the thermotropic liquid crystal 5CB. Better accuracy of VOC prediction is obtained for the hybrid gels composed of a PDMS matrix combined with the BMIMCl ionic liquid, and the use of this hydrophobic matrix reduces the effect of humidity on the sensing performance when compared to the gelatin counterpart. VOCs interact with all the moieties of the hybrid gel multicomponent system; thus, VOC correct classification depends not only on the polymeric matrix used, but also on the IL selected, which seems to be key to achieve VOCs discrimination at 50% RH. Thus, hybrid gels' tunable formulation offers the potential for designing complementary sensors for e-nose systems operable under different RH conditions.
The roles of intra‐ and interspecific gene flow in speciation and species evolution are topics of great current interest in molecular ecology and evolutionary biology. Recent modelling studies call ...for new empirical data to test hypotheses arising from the recent shift from a ‘whole‐genome reproductive isolation’ view to a ‘genic’ view of species and speciation. Particularly scarce (and thus of particular interest) are molecular genetic data on recently radiated, naturally hybridizing species in strongly structured and species‐rich environments. Here, we studied four sympatric plant species (Pitcairnia spp.; Bromeliaceae) adapted to Neotropical inselbergs (isolated outcrops resembling habitat ‘islands’ in tropical rainforests) using nuclear and plastid DNA. Patterns of plastid DNA haplotype sharing and nuclear genomic admixture suggest the presence of both, incomplete lineage sorting and interspecific gene flow over extended periods of time. Integrity and cohesion of inselberg species of Pitcairnia are maintained despite introgression and in the face of extremely low within‐species migration rates (Nem < 1 migrant per generation). Cross‐evaluation of our genetic data against published pollination experiments indicate that species integrity is maintained by the simultaneous action of multiple prezygotic barriers, including flowering phenology, pollinator isolation and divergent mating systems. Postzygotic Bateson–Dobzhansky–Muller incompatibilities appear to contribute to isolation, as suggested by asymmetric introgression rates of single loci. Our results suggest that incomplete lineage sorting, hybridization and introgression form integral aspects of adaptive radiation in Neotropical inselberg ‘archipelagos’. Inselbergs with multiple closely related co‐occurring species should be of special interest to students of speciation in mountain systems, and to ongoing conservation programmes in the Atlantic Rainforest biodiversity hotspot.
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