Tailoring natural-based oleogels combining ethylcellulose and virgin coconut oil

Oleogels are becoming an attractive research field, since they have recently been shown to be feasible for the food and pharmaceutical sectors and provided some insights into the biomedical area. In this work, edible oleogels were tailored through the combination of ethylcellulose (EC), a gelling agent, with virgin coconut oil (VCO), vegetable oil derived from coconut. The influence of the different EC and VCO ratios on the structural, physical, and thermal properties of the oleogels was studied. All EC/VCO-based oleogels presented a stable network with a viscoelastic nature, adequate structural stability, modulable stiffness, high oil-binding capability, antioxidant activity, and good thermal stability, evidencing the EC and VCOâ s good compatibility.The authors acknowledge financial support from the Portuguese FCT (SFRH/BPD/93697/2013, and CEECIND/01306/2018). This work is also financially supported by the FCT R&D&I projects with references POCI-01-0145-FEDER-029813 (PTDC/CTM-CTM/29813/2017), POCI-01-0145-FEDER-031570 (PTDC/BII-BIO/31570/2017), and TERM RES Hub, Ref Norte-01-0145-FEDER-02219015

Collagen membrane from bovine pericardium for treatment of long bone defect

The treatment of bone regeneration failures has been constantly improved with the study of new biomaterials. Techgraft® is a collagen membrane derived from bovine pericardium, which has been shown to have biocompatibility and effectiveness in tissue repair. However, its use in orthopedics has not yet been evaluated. Therefore, the purpose of this study was to characterize a bovine pericardium collagen membrane and evaluate the effects of its use in the regeneration of a bone defect in rat tibia. Scanning electron microscopy, atomic force microscopy, weight lost and water uptake tests, and mechanical test were performed. Afterwards, the membrane was tested in an experimental study, using 12 male Sprague Dawley rats. A bone defect was surgically made in tibiae of animals, which were assigned to two groups (n = 6): bone defect treated with collagen membrane (TG) and bone defect without treatment (CONT). Then, tibiae were submitted to micro-CT. The membranes preserved their natural collagen characteristics, presenting great strength, high water absorption, hydrophilicity, and almost complete dissolution in 30 days. In the experimental study, the membrane enhanced the growth of bone tissue in contact with its surface. A higher bone volume and trabeculae number and less trabecular space was observed in bone defects of the membrane group compared to the control group at 21 days. In conclusion, the Techgraft membrane seems to have favorable characteristics for treatment of long bone repair.The authors gratefully acknowledge the financial support from the São Paulo Research Foundation (reference 2017/20051-0) and the scholarship from the Coordination for the Improvement of Higher Education Personnel

The influence of the Mediterranean climate on vernacular architecture : a comparative analysis between the vernacular responsive architecture of southern Portugal and north of Egypt

Mediterranean vernacular architecture was developed not only with respect to environmental and climatic factors but also with respect to culture, traditional construction materials and morphology. Despite the far distance between Portugal and Egypt, it was possible to find similar vernacular strategies under the influence of the Mediterranean climate and both Roman and Arab cultures. The paper adopted an explanatory qualitative analysis and comparative synthesis methods for vernacular passive and climatic responsive strategies for two regions. Covering from site planning, building design till building materials used through considering topography, resources, historic and cultural aspects. The outcomes of this research allow for understanding how different passive solar strategies and the use of natural energy sources can contribute to achieve appropriate indoor comfort conditions for contemporary practice. The paper draws a set of recommendations for more in-depth quantitative survey and energy efficiency measurements in Mediterranean climate

Development and characterisation of cytocompatible polyester substrates with tunable mechanical properties and degradation rate

Although it has been repeatedly indicated the importance to develop implantable devices and cell culture substrates with tissue-specific rigidity, current commercially available products, in particular cell culture substrates, have rigidity values well above most tissues in the body. Herein, six resorbable polyester films were fabricated using compression moulding with a thermal presser into films with tailored stiffness by appropriately selecting the ratio of their building up monomers (e.g. lactide, glycolide, trimethylene carbonate, dioxanone, ε-caprolactone). Typical NMR and FTIR spectra were obtained, suggesting that the fabrication process did not have a negative effect on the conformation of the polymers. Surface roughness analysis revealed no apparent differences between the films as a function of polymer composition. Subject to polymer composition, polymeric films were obtained with glass transition temperatures from -52 °C to 61 °C; contact angles in water from 81 ° to 94 °; storage modulus from 108 MPa to 2,756 MPa and loss modulus from 8 MPa to 507 MPa (both in wet state, at 1 Hz frequency and at 37 °C); ultimate tensile strength from 8 MPa to 62 MPa, toughness from 23 MJ/m3 to 287 MJ/m3, strain at break from 3 % to 278 %, macro-scale Young's modulus from 110 MPa to 2,184 MPa (all in wet state); and nano-scale Young's modulus from 6 kPa to 15,019 kPa (in wet state). With respect to in vitro degradation in phosphate buffered saline at 37 °C, some polymeric films [e.g. poly(glycolide-lactide) 30 / 70] started degrading from day 7 (shortest timepoint assessed), whilst others [e.g. poly(glycolide-co-ε-caprolactone) 10 / 90] were more resilient to degradation up to day 21 (longest timepoint assessed). In vitro biological analysis using human dermal fibroblasts and a human monocyte cell line (THP-1) showed the potential of the polymeric films to support cell growth and controlled immune response. Evidently, the selected polymers exhibited properties suitable for a range of clinical indications.This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie, grant agreement no. 676338; the Widespread: Twinning, grant agreement no. 810850; and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement no. 866126. This work was also supported by Science Foundation Ireland, Career Development Award, grant agreement no. 15/CDA/3629 and Science Foundation Ireland/European Regional Development Fund, grant agreement no. 13/RC/2073. We would also like to thank Darlene Nebinger, Danielle Lord and Oswaldo Fabian from Medtronic North Haven, USA, for all their technical/experimental support

Thermal performance and comfort conditions analysis of a vernacular Palafitic timber building in Portuguese Coastline context

The palafitic timber constructions of the central Portuguese coastline are an example of the adaptation to site-specific conditions (climate and sand landscape morphodynamics) using the available endogenous resources. Thus, in a context of environmental awareness and climate change, it is relevant to understand their features/strategies and how they perform. This work analyses the energy performance and thermal condition evaluation of a vernacular timber building–palheiro–from Praia de Mira, through in situ measurements, subjective analysis and energy simulation provided by DesignBuilder/EnergyPlus. The results show a good or satisfactory thermal performance during most of the seasons by passive means only. Despite, it was not possible to guarantee thermal comfort conditions for the occupants during winter. In the energy performance analysis, five scenarios, with different external walls, were compared. In the two scenarios that satisfy the maximum U-value for the climate zone, the current conventional building had a slightly better performance on heating and cooling (less 1.1 and 1.4 kWh/m2, respectively) than the timber building. However, the difference between the two construction solutions is not substantial in the annual energy demand (2.5 kWh/m2, 7.3%), indicating that timber structures are suitable in this mild climate area.POCI-01-0145-FEDER-029328; PD/BD/113641/2015. FEDER funds through the Competitively and Internationalization Operational Programme (POCI) and by national funds through FCT (Foundation for Science and Technology) within the scope of the project with the reference POCI-01-0145-FEDER-029328 and of the PhD grant with the reference PD/BD/113641/2015, that were fundamental for the development of this stud

The potential of the reed as a regenerative building material—characterisation of its durability, physical, and thermal performances

Knowing the properties of vernacular materials is crucial to heritage conservation and to develop innovative solutions. Reed, considered to be a carbon-neutral and a carbon dioxide sink material, has been used for centuries for diverse uses. Its high availability and properties made it a popular building material, including in Portuguese vernacular architecture. An experimental investigation was conducted to evaluate the physical performance, thermal performance, and durability of the reed found in Portugal since the characterisation of this material was not found in previous studies. The influence of geometric characteristics and the presence of nodes on these properties were also analysed, and the results showed that they are irrelevant. The studied reeds were found to have an adequate thermal performance to be used as thermal insulation. Their thermal resistance (1.8 m2·°C/W) and thermal conductivity (0.06 W/m·°C) are under the requirements defined by Portuguese regulations on thermal insulation materials. Overall, the physical characteristics (moisture content, density, and retraction) are compatible to its use in the construction. Concerning durability, there was only a trend for mould growth in particular environments. The results provide valuable data to be considered in the development of new construction products based on this natural and renewable material. Additionally, considering the studied samples, the reed found in Portugal has characteristics suitable for use as a building material, especially as a thermal insulation material.FEDER funds through the Competitively and Internationalization Operational Programme (POCI) and by national funds through FCT (the Foundation for Science and Technology) within the scope of the project with the reference POCI-01-0145-FEDER-029328, reVer

Chitosan-based hierarchical scaffolds crosslinked with genipin

Osteochondral defects present significant challenges for effective tissue regeneration due to the complex composition of bone and cartilage. To address this challenge, this study presents the fabrication of hierarchical scaffolds combining chitosan/β-tricalcium phosphate (β-TCP) to simulate a bone-like layer, interconnected with a silk fibroin layer to mimic cartilage, thus replicating the cartilage-like layer to mimic the native osteochondral tissue architecture. The scaffolds were produced by freeze-drying and then crosslinking with genipin. They have a crosslinking degree of up to 24%, which promotes a structural rearrangement and improved connection between the different layers. Micro-CT analysis demonstrated that the structures have distinct porosity values on their top layer (up to 84%), interface (up to 65%), and bottom layer (up to 77%) and are dependent on the concentration of β-tricalcium phosphate used. Both layers were confirmed to be clearly defined by the distribution of the components throughout the constructs, showing adequate mechanical properties for biomedical use. The scaffolds exhibited lower weight loss (up to 7%, 15 days) after enzymatic degradation due to the combined effects of genipin crosslinking and β-TCP incorporation. In vitro studies showed that the constructs supported ATDC5 chondrocyte-like cells and MC3T3 osteoblast-like cells in duo culture conditions, providing a suitable environment for cell adhesion and proliferation for up to 14 days. Overall, the physicochemical properties and biological results of the developed chitosan/β-tricalcium phosphate/silk fibroin bilayered scaffolds suggest that they may be potential candidates for osteochondral tissue strategies.This study was partially financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), PVE 407035/2013-3. This work is also financially supported by Portuguese FCT (PD/BD/135247/2017, SFRH/BPD/93697/2013, DL 57/2016/CP1377/CT0054 (https://doi.org/10.54499/DL57/2016/CP1377/CT0054), CEECINST/00018/2021), PhD programme in Advanced Therapies for Health (PATH) (PD/00169/2013), FCT R&D&I projects with references PTDC/BII-BIO/31570/2017, PTDC/CTM-CTM//29813/2017, and PTDC/CTM-BIO/4706/2014- (POCI-01-0145-FEDER-016716). The authors would like to thank the contributions to this research from the project “TERM RES Hub—Scientific Infrastructure for Tissue Engineering and Regenerative Medicine”, reference PINFRA/22190/2016 (Norte-01-0145-FEDER-022190), funded by the Portuguese National Science Foundation (FCT) in cooperation with the Northern Portugal Regional Coordination and Development Commission (CCDR-N), for providing relevant lab facilities, state-of-the-art equipment, and highly qualified human resources

Structural monitoring and modeling of the mechanical deformation of three-dimensional printed poly(ε-caprolactone) scaffolds

Three-dimensional (3D) printed poly(ε-caprolactone) (PCL) based scaffolds have being proposed for different tissue engineering applications. This study addresses the design and fabrication of 3D PCL constructs with different struts alignments at 90°, 45° and 90° with offset. The morphology and the mechanical behavior under uniaxial compressive load were assessed at different strain percentages. The combination of a new compressionCT device and micro computed tomography (micro-CT) allowed understanding the influence of pore geometry under controlled compressive strain in the mechanical and structural behavior of PCL constructs. Finite element analysis (FEA) was applied using the micro-CT data to modulate the mechanical response and compare with the conventional uniaxial compression tests. Scanning electron microscopic analysis showed a very high level of reproducibility and a low error comparing with the theoretical values, confirming that the alignment and the dimensional features of the printed struts are reliable. The mechanical tests showed that the 90° architecture presented the highest stiffness. With the compressionCT device was observed that the 90° and 90° with offset architectures presented similar values of porosity at same strain and similar pore size, contrary to the 45° architecture. Thus, pore geometric configurations affected significantly the deformability of the all PCL scaffolds under compression. The prediction of the FEA showed a good agreement to the conventional mechanical tests revealing the areas more affected under compression load. The methodology proposed in this study using 3D printed scaffolds with compressionCT device and FEA is a framework that offers great potential in understanding the mechanical and structural behavior of soft systems for different applications, including for the biomedical engineering field.The author Fernandes E M acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) and 'Programa Operacional Potencial Humano-POPH' and 'Fundo Social Europeu-FSE' for the post-doctoral grant (SFRH/BPD/96197/2013).info:eu-repo/semantics/publishedVersio

Adaptações no Serviço de Cirurgia Vascular do CHULN durante a pandemia de COVID-19 e impacto na atividade global

© SPACVWith the onset of the SARS-CoV-2 pandemic in early 2020, health services and personnel adapted their resources to mitigate and control the outbreak. These needs inevitably led to adaptations in most medical and surgical departments, including in our Vascular Surgery department. As we are facing a second outbreak of this pandemic, with unpredictable outcomes and repercussions in health services, it is crucial to learn from previous experiences and share strategies to perform the best care to our patients, despite the restrictions that have been imposed. Through this paper, we review the adaptations in Centro Hospitalar Universitário Lisboa Norte and particularly in our department to overcome the pandemic. We also assess the impact of these changes in our activity and compare with the experience of other fellow surgeons. With an upcoming second outbreak, it is crucial to learn from this and other departments’ experiences to overcome a potential health crisis.info:eu-repo/semantics/publishedVersio

Advanced polymeric membranes as biomaterials based on marine sources envisaging the regeneration of human tissues

The self-repair capacity of human tissue is limited, motivating the arising of tissue engineering (TE) in building temporary scaffolds that envisage the regeneration of human tissues, including articular cartilage. However, despite the large number of preclinical data available, current therapies are not yet capable of fully restoring the entire healthy structure and function on this tissue when significantly damaged. For this reason, new biomaterial approaches are needed, and the present work proposes the development and characterization of innovative polymeric membranes formed by blending marine origin polymers, in a chemical free cross-linking approach, as biomaterials for tissue regeneration. The results confirmed the production of polyelectrolyte complexes molded as membranes, with structural stability resulting from natural intermolecular interactions between the marine biopolymers collagen, chitosan and fucoidan. Furthermore, the polymeric membranes presented adequate swelling ability without compromising cohesiveness (between 300 and 600%), appropriate surface properties, revealing mechanical properties similar to native articular cartilage. From the different formulations studied, the ones performing better were the ones produced with 3 % shark collagen, 3% chitosan and 10% fucoidan, as well as with 5% jellyfish collagen, 3% shark collagen, 3% chitosan and 10% fucoidan. Overall, the novel marine polymeric membranes demonstrated to have promising chemical, and physical properties for tissue engineering approaches, namely as thin biomaterial that can be applied over the damaged articular cartilage aiming its regeneration.The authors would like to acknowledge the Portuguese Foundation of Science and Technology (FCT) for Ph.D. fellowship (D. N. Carvalho, under the scope of doctoral program TERM&SC, ref. PD/BD/143044/2018), post-doctoral fellowship (L.C. Rodrigues, ref. SFRH/BPD/93697/2013) and research project with ref. PTDC/CTM-CTM/29813/2017-(POCI-01-0145-FEDER-029813). The authors also thank Jellagen Ltd. (UK) for the provision of purified jellyfish collagen and Julio Maroto (Fundación CETMAR, Vigo, Spain) for the kind offer of the squid pens for chitosan production.This work has been partially funded by ERDF under the scope of the Atlantic Area Program through project EAPA_151/2016 (BLUEHUMAN)