21 research outputs found

    Anomalous oriented attachment growth behavior on SnO2 nanocrystals

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    This work reports a detailed characterization of an anomalous oriented attachment behaviour for SnO2 nanocrystals. Our results evidenced an anisotropic growth for two identical 〈110〉 directions, which are equivalent according to the SnO2 crystallographic structure symmetry. A hypothesis is proposed to describe this behaviour

    Arabidopsis thaliana SPF1 and SPF2 are nuclear-located ULP2-like SUMO proteases that act downstream of SIZ1 in plant development

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    Post-translational modifiers such as the small ubiquitin-like modifier (SUMO) peptide act as fast and reversible protein regulators. Functional characterization of the sumoylation machinery has determined the key regulatory role that SUMO plays in plant development. Unlike components of the SUMO conjugation pathway, SUMO proteases (ULPs) are encoded by a relatively large gene family and are potential sources of specificity within the pathway. This study reports a thorough comparative genomics and phylogenetic characterization of plant ULPs, revealing the presence of one ULP1-like and three ULP2-like SUMO protease subgroups within plant genomes. As representatives of an under-studied subgroup, Arabidopsis SPF1 and SPF2 were subjected to functional characterization. Loss-of-function mutants implicated both proteins with vegetative growth, flowering time, and seed size and yield. Mutants constitutively accumulated SUMO conjugates, and yeast complementation assays associated these proteins with the function of ScUlp2 but not ScUlp1. Fluorescence imaging placed both proteins in the plant cell nucleoplasm. Transcriptomics analysis indicated strong regulatory involvement in secondary metabolism, cell wall remodelling, and nitrate assimilation. Furthermore, developmental defects of the spf1-1 spf2-2 (spf1/2) double-mutant opposed those of the major E3 ligase siz1 mutant and, most significantly, developmental and transcriptomic characterization of the siz1 spf1/2 triple-mutant placed SIZ1 as epistatic to SPF1 and SPF2.We thank Mark Hochstrasser (Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA) for kindly providing the ulp1-ts yeast mutant strain. This research was funded by FEDER (through COMPETE), and by Fundacao para a Ciencia e Tecnologia (FCT), within the scope of project SUMOdulator (FCOMP-01-0124-FEDER-028459 and PTDC/BIA-PLA/3850/2012). PHC was supported by FCT (SFRH/BD/44484/2008). HA and FF were supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000007 and Norte-01-0145-FEDER-000008, respectively). The work was supported by FEDER through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT, within the framework of projects 'Rede de Investigacao em Biodiversidade e Biologia Evolutiva' (POCI-01-0145-FEDER-006821) and 'Institute for Research and Innovation in Health Sciences' (POCI-01-0145-FEDER-007274). This research was also supported by a grant from the Spanish Ministerio de Ciencia y Tecnologia (AGL2016-75819-C2-1-R) and FEDER (PCQ, AGC, ERB)

    Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study

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    : The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity > 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI

    Electrical properties of SnO 2

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    Dopant segregation analysis on Sb:SnO2 nanocrystals

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    The development of reliable nanostructured devices is intrinsically dependent on the description and manipulation of materials properties at the atomic scale. Consequently, several technological advances are dependent on improvements in the characterization techniques and in the models used to describe the properties of nanosized materials as a function of the synthesis parameters. The evaluation of doping element distributions in nanocrystals is directly linked to fundamental aspects that define the properties of the material, such as surface-energy distribution, nanoparticle shape, and crystal growth mechanism. However, this is still one of the most challenging tasks in the characterization of materials because of the required spatial resolution and other various restrictions from quantitative characterization techniques, such as sample degradation and signal-to-noise ratio. This paper addresses the dopant segregation characterization for two antimony-doped tin oxide (Sb:SnO2 ) systems, with different Sb doping levels, by the combined use of experimental and simulated highresolution transmission electron microscopy (HRTEM) images and surface-energy ab initio calculations. The applied methodology provided threedimensional models with geometrical and compositional information that were demonstrated to be self-consistent and correspond to the systems mean properties. The results evidence that the dopant distribution configuration is dependent on the system composition and that dopant atom redistribution may be an active mechanism for the overall surface-energy minimization

    Deposition of controlled thickness ultrathin SnO2 : Sb films by spin-coating

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    The technological interest in transparent conductive oxide films (TCOs) has motivated several works in processing techniques, in order to obtain adequate routes to application. In this way, this work describes a new route to obtain antimony-doped tin oxide (ATO) films, based in colloidal dispersions of oxide nanocrystals. The nanoparticles were obtained by a hydrolisis method, using SnCl2 and SbCl3 in ethanolic solutions. The residual halides were removed by dyalisis, obtaining a limpid and transparent colloidal suspension. By this, the method offers the advantage of producing ultrathin films without organic contaminants. This route was employed to produce films with 5, 10, 14, and 18 mol% Sb doping, with thickness ranging from 40 to 70 nm. The physical characterization of the samples showed a uniform layer deposition, resulting in good packing density and high transmittance. A preliminar electrical study confirmed the low electrical resistivity even in the ultrathin films, in such level similar of reported data. The method described is similar in some aspects to layer-by-layer (LbL) techniques, allowing fine control of thickness and interesting properties for ultrathin films, however, with low cost when compared to similar routes

    Under pressure: an integrated assessment of human activities and their potential impact on the ecosystem components of the Southern Brazilian continental shelf

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    Abstract Economic activities in the South Brazilian Shelf (SBS) are concentrated on the coast, causing several impacts. To balance biodiversity and habitat conservation in coastal and marine areas with human activities relevant to society, it is important to identify and understand those sectors and pressures. We conducted an analysis to assess ecosystem risks from multiple drivers and pressures in the continental shelf that extends from the Southernmost point of Brazil (Chuí) to Cabo Frio cape, in Rio de Janeiro State. We used the Integrated Ecosystem Assessment (IEA) methodology, a framework for implementing ecosystem-based management grounded on five steps: scoping, indicator development, ecosystem assessment, risk analysis, and management strategy evaluation. This work presents the scoping step consisting of a semi-quantitative assessment identifying sector–pressure–ecological component pressure pathways. Subsequently, these pathways were scored using expert judgment supported by literature and data, regarding their level of overlap with each ecosystem component, frequency of occurrence, and degree of impact, enabling estimation of the magnitude of impact risk arising from each one of the sectors and pressures. The assessment involved 20 experts from multiple disciplines and backgrounds. To validate the results, we conducted a thorough literature review and engaged in further discussions with relevant stakeholders. As a result, 16 sectors and 19 pressures were identified as impacting 18 ecological components. Fishing, land-based industry, tourism and recreation, wastewater, and coastal infrastructure represented the main economic sectors impacting the area. The major associated pressures were the incidental catch of species, the introduction of contaminants and organic matter into the water, and the generation of waste. The most affected ecosystem components were, in turn, those located on or close to the coast, such as mangroves, saltmarshes, and rocky reefs while the preeminent impacted taxonomic groups were elasmobranchs, seabirds, reptiles, mammals, and bony fish. The literature review supported the expert assessment, and the stakeholders’ workshop endorsed our findings. Additionally, this assessment highlights the need to implement public policies that focus on reducing the impact of the most influential sectors and pressures and the necessity of strengthening research and monitoring. Identifying these priorities for integrated coastal and marine management is crucial, and our research outcomes can be key in promoting regional ocean sustainability
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