138 research outputs found

    Assessing the Potential of Sensors Based on LbL and Sputtering Films

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    Funding text This research was funded by the project PCIF/GFC/0078/2018: influence of forest VOCs (volatile organic compounds) on extreme fire behavior at Fundação para a Ciência e a Tecnologia (FCT). The authors also thankful for the research center grants no. UIDB/FIS/04559/2020 and no. UIDP/FIS/04559/2020 (LIBPhys) from FCT/MCTES, Portugal.A new theory suggests that flammable gases generated by heated vegetation, in particular the volatile organic compounds (VOC) common to Mediterranean plants, may, under certain topographic and wind conditions, accumulate in locations where, after the arrival of the ignition source, they rapidly burst into flames as explosions. Hence, there is a need for the development of a system that can monitor the development of these compounds. In this work, a sensor's array is proposed as a method for monitoring the amount of eucalyptol and α-pinene, the major VOC compounds of the Eucalyptus and Pine trees. The detection of the target compounds was assessed using the impedance spectroscopy response of thin films. Combinations of layers of polyelectrolytes, such as poly(allylamine hydrochloride) (PAH), polyethyleneimine (PEI), poly(sodium 4-sytrenesulfonate) (PSS) graphene oxide (GO), and non/functionalized multiwall nanotubes (MWCNT-COOH or MWCNT), namely, PAH/GO, PEI/PSS, PEI/GO, PAH/MWCNT, PAH/MWCNT-COOH, films, and TiO2 and ZnO sputtered films, were deposited onto ceramic supports coated with gold interdigitated electrodes. The results showed that concentrations of the target VOCs, within the range of 68 to 999 ppmv, can be easily distinguished by analyzing the impedance spectra, particularly in the case of the ZnO- and PAH/GO-film-based sensors, which showed the best results in the detection of the target compounds. Through principal component analysis (PCA), the best set of features attained for the ZnO and PAH/GO based sensor devices revealed a linear trend of the PCA's first principal component with the concentration within the range 109 and 807 ppmv. Thus, the values of sensitivity to eucalyptol and α-pinene concentrations, which were (2.2 ± 0.3) × 10-4 and (5.0 ± 0.7) × 10-5 per decade, respectively, as well as resolutions of 118 and 136 ppbv, respectively, were identified.publishersversionpublishe

    Taxonomic and functional diversity of insect herbivore assemblages associated with the canopy-dominant trees of the Azorean native forest.

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    Oceanic islands have been providing important insights on the structuring of ecological communities and, under the context of the present biodiversity crisis, they are paramount to assess the effects of biological invasions on community assembly. In this study we compare the taxonomic and functional diversity of insect herbivore assemblages associated with the dominant tree species of Azorean native forests and investigate the ecological processes that may have originated current patterns of plant-herbivore associations. Five dominant trees?Erica azorica, Ilex perado subsp. azorica, Juniperus brevifolia, Laurus azorica and Vaccinium cylindraceum?were sampled in the remnants of the native forest of Terceira Island (Azores) using a standardised methodology. The taxonomic and functional diversity of insect herbivore assemblages was assessed using complementary metrics and beta diversity partitioning analysis (species replacement and richness differences) aiming to evaluate the variation in insect herbivore assemblages within and between the study plant species. Sixty two insect species, mostly bugs (Hemiptera) and caterpillars (Lepidoptera), were found in the five study plants with indigenous (endemic and native non-endemic) insects occurring with higher species richness and abundance than introduced ones. Species replacement was the most important component of insect herbivore taxonomic beta diversity while differences in trait richness played a major role on functional beta diversity. The endemic E. azorica stands out from the other study plants by having associated a very distinct insect herbivore assemblage with a particular set of functional attributes, mainly composed by large bodied and long shaped species that feed by chewing. Despite the progressive biotic homogenization witnessed in the Azores during the last few decades, several strong associations between the endemic trees and their indigenous insect herbivores remain

    Effect of PEDOT:PSS with secondary dopants and DBD plasma treatment on the conductive properties of polyester fabrics

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    [Excerpt] Introduction Smart textiles have the capability to interact with the surrounding environment and react in different ways, namely in electrical conduction. The conductive properties of these materials are useful in medical, healthcare, and protective clothing.This research was funded by FEDER funds through the Operational Competitiveness Program– COMPETE, under the projects POCI-01-0247-FEDER-068924, and by National Funds through Fundação para a Ciência e Tecnologia (FCT), under the project UID/CTM/00264/2020. Ana Isabel Ribeiro and Cátia Alves acknowledge FCT, MCTES, FSE, and UE PhD grant SFRH/BD/145269/2019 and 2022.10454.BD

    Towards a natural classification of Sapotaceae subfamily Chrysophylloideae in the Neotropics

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    Generic limits of Chrysophyllum and Pouteria (Chrysophylloideae, Sapotaceae) have been found to be untenable. We here search for natural lineages in Neotropical Chrysophylloideae by sampling 101 terminals for molecular sequences of nuclear ribosomal DNA (external and internal transcribed spacer), the nuclear gene RPB2 and 17 morphological characters. Data were analysed with Bayesian inference and parsimony jackknifing. Morphological traits were finally optimized onto the tree to identify the most coherent characters. The resulting phylogenetic tree suggests that the limits of the well-known genera Chrysophyllum and Pouteria must be amended. Diploon, Ecclinusa and Elaeoluma can be maintained and Chrysophyllum sections Ragala section Prieurella and the satellite genera Achrouteria, Cornuella, Martiusella and Nemaluma merit generic resurrection. Lucuma may be restored if the type species belongs to the clade. The accepted genera Chromolucuma, Pradosia and Sarcaulus gain strong clade support, but are embedded in a core clade of Pouteria and may be relegated to the subgeneric level if morphological studies cannot provide evidence concurring with narrow generic concepts. Circumscriptions of Micropholis and Chrysophyllum sections Chrysophyllum and Villocuspis remain unclear and must be explored by using an extended taxon sampling. We predict that yet-to-be-analysed species of Pouteria sections Franchetella, Gayella, Oxythece and Pouteria and members of the currently accepted genera Chromolucuma, Pradosia and Sarcaulus will fall inside the core clade of Pouteria when analysed. © 2017 The Linnean Society of London

    In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

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    Artemisinin is the active antimalarial compound obtained from the leaves of Artemisia annua L. Artemisinin, and its semi-synthetic derivatives, are the main drugs used to treat multi-drug-resistant Plasmodium falciparum (one of the human malaria parasite species). The in vitro susceptibility of P. falciparum K1 and 3d7 strains and field isolates from the state of Amazonas, Brazil, to A. annua infusions (5 g dry leaves in 1 L of boiling water) and the drug standards chloroquine, quinine and artemisinin were evaluated. The A. annua used was cultivated in three Amazon ecosystems (várzea, terra preta de índio and terra firme) and in the city of Paulínia, state of São Paulo, Brazil. Artemisinin levels in the A. annua leaves used were 0.90-1.13% (m/m). The concentration of artemisinin in the infusions was 40-46 mg/L. Field P. falciparum isolates were resistant to chloroquine and sensitive to quinine and artemisinin. The average 50% inhibition concentration values for A. annua infusions against field isolates were 0.11-0.14 μL/mL (these infusions exhibited artemisinin concentrations of 4.7-5.6 ng/mL) and were active in vitro against P. falciparum due to their artemisinin concentration. No synergistic effect was observed for artemisinin in the infusions

    Synthesis of Analogues of Thyroid Hormones: Nuclear Receptor Modulators

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    Thyroid hormones are essential for the development and differentiation of all cells of the human body. This work reports the synthesis of some synthetic structural analogues of thyroid hormones, which may be modulators of the thyroid hormone receptor. The known compounds GC-1 (Sobetirome) and CG-24 were successfully prepared and two novel analogous molecules were also synthesized by a new and efficient synthetic methodology. DOI: http://dx.doi.org/10.17807/orbital.v7i3.73

    The Iberian Massif Landscape and Fluvial Network in Portugal: a geoheritage inventory based on the scientific value

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    Integrated in the national inventory of geological heritage in Portugal, the “Iberian Massif Landscape and Fluvial Network” was selected as one of the geological frameworks with international relevance. Taking into account the diversity of geomorphological and stratigraphic elements occurring in the Portuguese Iberian Massif, 38 geosites were selected in order to represent five themes related to the main geomorphological elements of the Iberian Massif Landscape: major residual landforms, granite landforms, tectonic landforms, correlative sediments, and fluvial landforms. For each theme, some sub-themes were defined, together with key-areas that were considered for the selection of geosites. A quantitative assessment of the scientific value and vulnerability of all geosites was undertaken using a methodology that numerically scores a set of criteria. Results highlight the Vilariça geosite with top-priority for management based on its high scientific value and high vulnerability, and the key-area of Miranda do Corvo-Lousã Basin because of the high concentration of geosites. The quantitative evaluation shows that seven geosites have high vulnerability and that special attention should be paid to sedimentary sections. These results allow the establishment of priorities for the management of geosites under the scope of a national geoconservation strategy.This paper results of the research done at the University of Minho and at the Geology Centre of the University of Porto, both partially founded by the Foundation for Science and Technology (strategic project with reference PEst-OE/CTE/UI0039/2014), and IMAR-CMA – University of Coimbra, sponsored by the Foundation for Science and Technology (Portugal).info:eu-repo/semantics/publishedVersio

    Influenza virus type/subtype and different infection profiles by age group during 2017/2018 season

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    DDI-INSA em colaboração com a Rede Portuguesa de Laboratórios para o Diagnóstico da GripeBackground: Influenza has a major impact in hospitalization during each influenza season. We analysed the influenza type/subtype distribution by age group and medical care wards (ambulatory, hospital, intensive care unit). Material and Methods: During 2017/2018 season, 14 hospitals from Portugal mainland and Atlantic Island (Azores and Madeira) reported to the National Influenza Centre 13747 cases of respiratory infection, all tested for influenza type and/or subtype. Epidemiological data: age, sample collection, hospital dwelling service and patient outcome were reported. Results: From the 13747 reported cases, 3717(27%) were influenza positive of which 2033 (55%) were influenza B, 722 (19%) A unsubtyped, 505 (14%) AH3, 442 (12%) AH1pdm09 and 15(0,1%) mixed infections. Influenza A was detected in 71% (204/208) of toddlers(<5 years) although in the remaining age groups influenza B was detected in more than 50% of the confirmed flu cases. Influenza B was the predominant virus in hospitalized and ICU influenza cases between 5-14 years (69% and 75%, respectively) and played a major role in elderly (65+ years) hospitalized and ICU cases(57% and 67%, respectively). AH1pdm09 virus was detected in 30% of the influenza confirmed ICU patients, 2.1 times more than in hospitalized cases in other wards and 3.3 times more than influenza AH1pdm09 cases in ambulatory care. Influenza mixed infection were detected sporadically,mainly in hospitalized and ICU patients. From 2080 known outcomes, 40(1.9%) patients deceased, influenza was confirmed in 11(28%) of these cases. Conclusions: Cocirculation of different influenza virus type/subtype may indicate different infection profiles by age groups and should guide influenza preventive/treatment measures.N/
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