225 research outputs found
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Wayfinding and Glaucoma: A Virtual Reality Experiment.
PurposeWayfinding, the process of determining and following a route between an origin and a destination, is an integral part of everyday tasks. The purpose of this study was to investigate the impact of glaucomatous visual field loss on wayfinding behavior using an immersive virtual reality (VR) environment.MethodsThis cross-sectional study included 31 glaucomatous patients and 20 healthy subjects without evidence of overall cognitive impairment. Wayfinding experiments were modeled after the Morris water maze navigation task and conducted in an immersive VR environment. Two rooms were built varying only in the complexity of the visual scene in order to promote allocentric-based (room A, with multiple visual cues) versus egocentric-based (room B, with single visual cue) spatial representations of the environment. Wayfinding tasks in each room consisted of revisiting previously visible targets that subsequently became invisible.ResultsFor room A, glaucoma patients spent on average 35.0 seconds to perform the wayfinding task, whereas healthy subjects spent an average of 24.4 seconds (P = 0.001). For room B, no statistically significant difference was seen on average time to complete the task (26.2 seconds versus 23.4 seconds, respectively; P = 0.514). For room A, each 1-dB worse binocular mean sensitivity was associated with 3.4% (P = 0.001) increase in time to complete the task.ConclusionsGlaucoma patients performed significantly worse on allocentric-based wayfinding tasks conducted in a VR environment, suggesting visual field loss may affect the construction of spatial cognitive maps relevant to successful wayfinding. VR environments may represent a useful approach for assessing functional vision endpoints for clinical trials of emerging therapies in ophthalmology
Phylogenetic structure of geographical co-occurrence among New World Triatominae species, vectors of Chagas disease
The tropical niche conservatism (TNC) hypothesis is one of the most prominent evolutionary hypotheses that has been supported as an explanation for the diversity gradients of several animal taxa, mainly vertebrates. However, the validity of TNC for less-known taxa such as disease vectors is not clear. Here, we test predictions of TNC in driving the geographical co-occurrence among triatomine species, vector insects of Chagas disease. We aim to infer the relative effects of ecological and evolutionary processes in determining triatomine species richness at broad spatial scales. Location: America. Taxon: Triatominae (Hemiptera: Reduviidae). Methods: We gathered distributional, phylogenetic and climatic information for 63 triatomine species. We apply the phylogenetic field (PF) framework based on the phylogenetic structure of species co-occurrences, considering their climatic preferences. We defined PFs of species by estimating the phylogenetic structure of species co-occurrence within a focal species’ range. Likewise, climatic conditions within focal species’ ranges were defined as their preferred climates. We applied a spatial-phylogenetic statistical framework to evaluate geographical variation of species’ co-occurrence and tested the significance of PFs based on biogeographically informed null models. Results: Phylogenetic fields of 17 out of 59 triatomine species showed a trend from overdispersed to clustered, coincident with tropical to subtropical–temperate climate. Triatomines co-occur with more closely related species in temperate areas and more distantly related species in tropical areas. Temperature seasonality was inversely related to the phylogenetic structure of co-occurrence within species ranges. Main conclusions: Geographical co-occurrence among triatomine species revealed a tropical to subtropical–temperate gradient from overdispersed to clustered PFs and a correspondence between the type of climate in which these species are found and their PFs. Phylogenetic structure within triatomine ranges is explained by their evolutionary history. Our study provides a methodological framework to evaluate the New World triatomine geographical co-occurrence patterns under a phylogenetic perspective and our results make an important contribution to the understanding of the broad-scale biodiversity patterns in Triatominae.Fil: Ceccarelli, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Justi, Silvia A.. Smithsonian Institution Museum Support Center; Estados Unidos. Walter Reed Army Institute of Research. Entomology Branch; Estados UnidosFil: Rabinovich, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Diniz Filho, José Alexandre F.. Universidade Federal de Goiás; BrasilFil: Villalobos, Fabricio. Universidade Federal de Goiás; Brasil. Instituto de Ecología; Méxic
Design of bio-based supramolecular structures through self-assembly of α-lactalbumin and lysozyme
Bovine α-lactalbumin (α-La) and lysozyme (Lys), two globular proteins with highly homologous tertiary structures and opposite isoelectric points, were used to produce bio-based supramolecular structures under various pH values (3, 7 and 11), temperatures (25, 50 and 75 °C) and times (15, 25 and 35 min) of heating. Isothermal titration calorimetry experiments showed protein interactions and demonstrated that structures were obtained from the mixture of α-La/Lys in molar ratio of 0.546. Structures were characterized in terms of morphology by transmission electron microscopy (TEM) and dynamic light scattering (DLS), conformational structure by circular dichroism and intrinsic fluorescence spectroscopy and stability by DLS. Results have shown that protein conformational structure and intermolecular interactions are controlled by the physicochemical conditions applied. The increase of heating temperature led to a significant decrease in size and polydispersity (PDI) of α-La–Lys supramolecular structures, while the increase of heating time, particularly at temperatures above 50 °C, promoted a significant increase in size and PDI. At pH 7 supramolecular structures were obtained at microscale – confirmed by optical microscopy – displaying also a high PDI (i.e. > 0.4). The minimum size and PDI (61 ± 2.3 nm and 0.14 ± 0.03, respectively) were produced at pH 11 for a heating treatment of 75 °C for 15 min, thus suggesting that these conditions could be considered as critical for supramolecular structure formation. Its size and morphology were confirmed by TEM showing a well-defined spherical form. Structures at these conditions showed to be stable at least for 30 or 90 days, when stored at 25 or 4 °C, respectively. Hence, α-La–Lys supramolecular structures showed properties that indicate that they are a promising delivery system for food and pharmaceutical applications.CNPq and CAPES, and their support to FAPEMIG and CNPEM-LNBio (Centro Nacional de Pesquisa em Energia e Materiais-Laboratório Nacional de Biociências) both from Brazil. Fundação para a Ciência e a Tecnologia. The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684), the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and the project “BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes”, REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER
High mobility group box 1 levels in large vessel vasculitis are not associated with disease activity but are influenced by age and statins
Introduction: Takayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV. Methods: Twenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay. Results: In GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 +/- 4.19 ng/ml vs. 4.17 +/- 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45-2.10) ng/ml vs. 1.46 (0.89-3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63-2.16) ng/ml vs. 0.75 (0.39-2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29-1.46) ng/ml vs. 1.93 (0.88-3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status. Conclusions: Patients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV
Mapping of trace elements on the island of sal (cape verde) and blood concentrations in inhabitants.
Geochemical mapping provides a set of information that allows easy
interpretation and helps in decision-making on public policies that address a balance
between health, environment and economy of a country.
The Sal island (Cape Verde) has an area of 216 km2. In this study, 60 topsoil samples
were collected, corresponding to a density of 1/7 km2. Chemical analysis, including
analytical quality control, was carried out following the recommendations of the "IGCP
259 - International Geochemical Mapping" project. The obtained map shows an
ecological risk for mercury. At the same sites, 50% of participants had blood mercury
levels above the guideline limit. The neuropsychologic assessment suggests a
correlation between blood mercury levels and the incidence of cognitive disorders. The
number of years participants resided in those danger areas correlated with cognitive
impairment. The results also point to the area of residency as a relevant exposure
factor. This strategy may be useful for predictive diagnosis in population screening for
cognitive impairment. Improved diagnostic results can be obtained using blood
mercury data along with Mini Mental State Examination (MMSE) scores
Ferramentas e Aspectos Práticos da TV Digital Técnica Projectos / Tools and Practical Aspects of Digital TV Technical Projects
A TV aberta é um importante ator de comunicação na sociedade contemporânea com alguns padrões de sucesso, entre eles o Sistema Brasileiro de Televisão Digital Terrestre (SBTVD-T). Este artigo discute aspectos relacionados à construção de um projeto técnico para obtenção de outorgas para o serviço de televisão e seus serviços ancilares no Brasil. Apresentamos algumas ferramentas de livre acesso que podem ser utilizadas para realizar tal atividade. Por fim, um estudo de caso apresenta a construção do projeto técnico da TV Universitária, uma emissora de TV da Universidade Federal do Rio Grande do Norte, Brasil. Como principal resultado, pretendeu-se preencher a lacuna de material técnico relacionado ao uso de ferramentas abertas e bases de dados governamentais para a construção de projetos técnicos de TV digital no Brasil
Aspectos da Legislação e Procedimentos para a Concessão da TV Digital e dos seus Serviços Auxiliares no Brasil / Legislation and Procedures Aspects for the Grant of Digital TV and Its Ancillary Services in Brazil
O serviço de radiodifusão sonora e de imagens continua sendo um dos principais veículos de mídia e informação da sociedade contemporânea e vem passando por um longo processo de alteração de seus aspectos regulatórios decorrente da implantação do Sistema Brasileiro de Televisão Digital Terrestre (SBTVD-T). Este artigo apresenta e discute os procedimentos para obtenção de outorgas para o serviço de televisão e seus serviços ancilares no Brasil. Como resultado principal, pretendeu-se preencher a lacuna por material técnico relacionado à discussão da legislação da TV digital no Brasil
PERIÓDICOS BRASILEIROS DA ÁREA DE ADMINISTRAÇÃO NO CONTEXTO DE INTERNACIONALIZAÇÃO DA PRODUÇÃO CIENTÍFICA
Este ensaio é fruto da experiência do autor como editor-chefe da RAE-Revista de Administração de Empresas entre 2009 e 2015, e reflete a sua visão sobre a gestão do processo editorial científico, sobre mecanismos de disseminação da produção científica, sobre estratégias de internacionalização dos periódicos brasileiros e sobre a necessidade de uma política de internacionalização para os periódicos brasileiros da área de administração
The influence of Fe2O3 doping on the pore structure and mechanical strength of TiO2-containing alumina obtained by freeze-casting
This work investigated TiO/FeO doped alumina prepared by the freeze-casting technique and using camphene as the solvent. Dendritic pores were formed in the TiO doped alumina, a structure conferred by the frozen camphene. Contrary to this trend, further FeO doping of TiO-containing alumina resulted in the formation of non-dendritic structures. This behavior was attributed to the higher density of α-FeO (5.24 g cm) when compared to α-AlO (3.95 g cm) and anatase TiO (3.89 g cm), which reduced critical solidification front velocity, thus forming material with different pore shape. FeO doping also improved the densification of TiO-alumina and inhibited the formation of cracks, reflected by superior mechanical strength with best results ∼150% higher for 10% FeO loaded samples as compared to TiO-alumina samples
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