Elastic properties of graphyne-based nanotubes

Graphyne nanotubes (GNTs) are nanostructures obtained from rolled up graphyne sheets, in the same way carbon nanotubes (CNTs) are obtained from graphene ones. Graphynes are 2D carbon-allotropes composed of atoms in sp and sp2 hybridized states. Similarly to conventional CNTs, GNTs can present different chiralities and electronic properties. Because of the acetylenic groups (triple bonds), GNTs exhibit large sidewall pores that influence their mechanical properties. In this work, we studied the mechanical response of GNTs under tensile stress using fully atomistic molecular dynamics simulations and density functional theory (DFT) calculations. Our results show that GNTs mechanical failure (fracture) occurs at larger strain values in comparison to corresponding CNTs, but paradoxically with smaller ultimate strength and Young's modulus values. This is a consequence of the combined effects of the existence of triple bonds and increased porosity/flexibility due to the presence of acetylenic groups

Holocene evolution of a barrier island system, Ria Formosa, South Portugal

Holocene evolution of the Ria Formosa barrier island system was studied through the examination of a large subsurface dataset acquired from 191 boreholes and five seismic refraction profiles. Two boreholes with total depths of 26 and 16.5 m were selected for a multi-proxy detailed laboratory analysis, including mean grain size distribution, organic matter (OM) content, color variation, shell identification, and benthic foraminifera assemblages. Selected cores are thought to be representative of the identified depositional sub-basins. Subsurface age data from 16 AMS C-14 dated samples were plotted against depth and resulted in a coherent age model of sedimentary infill. The system evolution was largely controlled by sediment availability, accommodation space, and Holocene sea level rise, first at a rapid rate of 7 mm/yr from 10 kcal yr BP to 7.25 kcal yr BP, followed by a slowdown to 1.1 mm/yr until present. A conceptual model for the origin and Holocene evolution of the Ria Formosa barrier island system implies three main steps, leading to the present system geomorphology: (1) marine flooding of incised palaeovalleys by the rapid transgression of palaeovalleys in the early Holocene(2) development of a proto-barrier island chain perched on Pleistocene detritic headlands and steeper interfluve areas during the early to middle Holoceneand (3) full development of the barrier islands chain and enclosing of the coastal lagoon, followed by the maturation of the system with subsequent siltation and salt marsh expansion from the middle Holocene until present. The onset of barrier system formation dates back to ca. 8 kcal yr BP, predating previously proposed age.SIHER project [PTDC/CTE-GIX112236/2009]EU Erasmus Mundus Joint Doctorate in Marine and Coastal Management (MACOMA) fellowship grant, under University of AlgarveEU Erasmus Mundus Joint Doctorate in Marine and Coastal Management (MACOMA) fellowship grant, under University of Cadi

Health-related quality of life in patients with venous leg ulcer treated in primary care in Brazil and Portugal

Background Venous ulcers constitute an important public health problem as they can cause disability with consequences for multiple dimensions of quality of life. Objective To describe the quality of life in patients with venous leg ulcer treated in primary care in two cities from Brazil and Portugal. Methods This was a cross-sectional comparative study with a non-probabilistic sample of 171 patients with venous leg ulcers who were treated in primary care in two cities from Brazil and Portugal, namely, Natal and Évora. A form covering sociodemographic and health data and the Medical Outcomes Study 36-Item Short-Form Health Survey were used, and descriptive and inferential analyses were performed. Results Significant differences in age and income were observed between the two samples. Patients with venous leg ulcer from Brazil had lower income and were younger than those from Portugal. Quality of life scores were significantly higher in Portugal for the physical aspects, pain, and social functioning, among domains, and for the physical health dimension and total score of QOL. Conclusion The quality of life was better in Portugal than in Brazil and the differences between the countries need further investigation

ATENA–A Novel Rapidly Manufactured Medical Invasive Ventilator Designed as a Response to the COVID-19 Pandemic: Testing Protocol, Safety, and Performance Validation

Background: The urgent need for mechanical ventilators to support respiratory insufficiency due to SARS-CoV-2 led to a worldwide effort to develop low-cost, easily assembled, and locally manufactured ventilators. The ATENA ventilator project was developed in a community-based approach targeting the development, prototyping, testing, and decentralized manufacturing of a new mechanical ventilator. Objective: This article aims to demonstrate ATENA's adequate performance and safety for clinical use. Material: ATENA is a low-cost ventilator that can be rapidly manufactured, easily assembled, and locally produced anywhere in the world. It was developed following the guidelines and requirements provided by European and International Regulatory Authorities (MHRA, ISO 86201) and National Authorities (INFARMED). The device was thoroughly tested using laboratory lung simulators and animal models. Results: The device meets all the regulatory requirements for pandemic ventilators. Additionally, the pre-clinical experiences demonstrated security and adequate ventilation and oxygenation, in vivo. Conclusion: The ATENA ventilator had a good performance in required tests in laboratory scenarios and pre-clinical studies. In a pandemic context, ATENA is perfectly suited for safely treating patients in need of mechanical ventilation.Financial support and sponsorship by CEiiA, INOV4COVID program, donations from scientific patronage, and commercial sales