866 research outputs found
Peptide-mediated targeted delivery system towards triple negative breast cancer treatment
About 2.1 million new diagnosed breast cancer cases among women were estimated for 2018. Triple negative breast cancer (TNBC), characterized by the absence of hormone receptors (estrogen and progesterone), lack of expression of epidermal growth factor receptor-2 and poor prognosis, represents 10-20% of all breast cancers. Hence, the identification of novel biomarkers for this type of breast cancer is highly relevant for an early diagnosis. Additionally, TNBC peptide ligands can be used to design powerful drug delivery systems that specifically target this type of breast cancer. Therefore, the following study aimed to
select and characterize novel peptides for a triple negative breast cancer murine mammary carcinoma cell line 4T1. Using phage display, 7 and 12 amino acid random peptide libraries were screened against the 4T1 cell line. A total of four rounds, plus a counter-selection round using the 3T3 murine fibroblast cell line, was performed. The enriched selective peptides were characterized and their binding capacity towards 4T1 tissue samples was confirmed by immunofluorescence and flow cytometry analysis. The selected peptides (4T1pep1 CPTASNTSC and 4T1pep2EVQSSKFPAHVS) were enriched over few rounds of selection and exhibited specific binding to the 4T1 cell line.
Exosomes derived from BJ cells were isolated by differential centrifugation and further characterized by nanoparticle tracking analysis, transmission electron microscopy (TEM), flow cytometry and western blot. Cell-derived exosomes were efficiently uptake by different TNBC cell lines (MDA-MB-231, MDA-MB-453, MDA-MB-157 and Hs 578T). Moreover, in vivo circulation times and biodistribuition experiments were accomplished to assess performance. The ultimate goal is to develop multifunctional exosomes decorated with the previously selected peptides to achieve a drug delivery system with increased affinity/selectivity for triple negative breast cancer cells. Targeted exosomes have led to a completely new paradigm for the therapeutic delivery of drug molecules to specific targets,
opening the door for new treatments of diseases caused by aberrant gene expression as cancer.info:eu-repo/semantics/publishedVersio
Exploring chemical compound space with a graph-based recommender system
With the availability of extensive databases of inorganic materials,
data-driven approaches leveraging machine learning have gained prominence in
materials science research. In this study, we propose an innovative adaptation
of data-driven concepts to the mapping and exploration of chemical compound
space. Recommender systems, widely utilized for suggesting items to users,
employ techniques such as collaborative filtering, which rely on bipartite
graphs composed of users, items, and their interactions. Building upon the Open
Quantum Materials Database (OQMD), we constructed a bipartite graph where
elements from the periodic table and sites within crystal structures are
treated as separate entities. The relationships between them, defined by the
presence of ions at specific sites and weighted according to the thermodynamic
stability of the respective compounds, allowed us to generate an embedding
space that contains vector representations for each ion and each site. Through
the correlation of ion-site occupancy with their respective distances within
the embedding space, we explored new ion-site occupancies, facilitating the
discovery of novel stable compounds. Moreover, the graph's embedding space
enabled a comprehensive examination of chemical similarities among elements,
and a detailed analysis of local geometries of sites. To demonstrate the
effectiveness and robustness of our method, we conducted a historical
evaluation using different versions of the OQMD and recommended new compounds
with Kagome lattices, showcasing the applicability of our approach to practical
materials design
Hacia un enfoque para el desarrollo profesional de los docentes: cómo trabajar con el pensamiento algebraico en los primeros años
This article received national funding from the FCT - Fundação para a Ciência e a
Tecnologia, IP, within the scope of the UIDEF - Unidade de Investigação e
Desenvolvimento em Educação e Formação - UIDB/04107/2020.This article presents the first intervention cycle of a design-based research
program on teacher professional development. The study aims to
understand how the formative process helped teachers to understand what
algebraic thinking means and how to work with it in the early years. Data
analysis was based on three principles of design: teacher’s role and
actions, professional learning tasks for teachers, and discursive
interactions among participants. The results suggest that these design
principles contributed to teachers’ understanding of the meaning of
algebraic thinking and how to promote it in elementary students.Este artículo presenta el primer ciclo de intervención de una investigación
basada en el diseño del desarrollo profesional docente. Su objetivo es
comprender cómo el proceso formativo ayudó a los maestros a
comprender qué significa el pensamiento algebraico y cómo trabajar con
él en los primeros. El análisis de datos se basó en tres principios de
diseño, papel y acciones del formador de docentes, tareas de aprendizaje
profesional para los docentes e interacciones discursivas entre los
participantes. Los resultados sugieren que los principios de diseño
contribuyeron a la comprensión del significado del pensamiento
algebraico y cómo promoverlo en los estudiantes de primaria.FCT - Fundação para a Ciência e a
Tecnologia UIDB/04107/202
An Evaluation System for University-Industry Partnership Sustainability: Enhancing Options for Entrepreneurial Universities
The concept of university–industry partnership sustainability (UIPS) stands for well-adjusted progress among key players from universities and industry by sustaining their welfare, both in the present and in the future. This paper sought to develop an evaluation system for UIPS. The need for such a system is justified at three levels: the micro level (i.e., research and innovation performance, transfer and absorptive capability, and technology development), the meso level (i.e., institutional arrangements, communication networks, and local and indigenous rules) and the macro level (i.e., supply and demand, regulations, financing, taxes, culture, traditions, market, climate, politics, demographics, and technology). The UIPS evaluation system developed in this study offers the possibility of calculating a fair value of UIPS and providing recommendations for improving university–industry (U–I) partnerships. This can be of great importance for entrepreneurial universities that would like to strengthen their corporate links and/or reduce/reverse the “hollowing effect” of globalisation in disadvantaged regions. Additionally, this paper also contains discussions on the advantages, limitations, and managerial implications of this proposal.info:eu-repo/semantics/publishedVersio
Exopolysaccharide production by Helicobacter pylori
Helicobacter pylori is a widespread Gram-negative bacterium that infects the
stomach of humans leading to the onset of several gastric disorders, such as, gastritis,
gastric ulcers, and cancers. Studies from developing countries with low socioeconomic
status and poor management of the drinking water suggest that it may serve as an
environmental reservoir of H. pylori and therefore contribute to human infection.
It has been reported that H. pylori has the ability to form microbial consortia
embedded by a highly hydrated exopolysaccharidic matrix (biofilms) on surfaces
exposed to water. The enhanced protection provided to microbial cells by the
exopolysaccharides (EPS) brings added concerns about the possibility of H. pylori
being transmitted through drinking water. H. pylori EPS as been reported to be
composed mainly by Gal:Glc:GlcN in a proportion of 1.0:2.1:7.0, respectively (Stark et
al., 1999).
The present work brings about microscopical evidences of the capability of H.
pilory to form free swimming bacterial aggregates and biofilms when submitted to
nutrient depletion and hydrodynamic stress. Evidences that H. pylori aggregation is an
exopolysaccharidic mediated phenomena both in planktonic and sessile states are also
showed. Ethanol fractioning of the material recovered from these aggregates revealed an
EPS composed of Gal:Glc:GlcN in a proportion of 1.0:0.4:1.6 respectively. A further
structural detail about this EPS is under progress
Ductility and durability of strain hardening cementitious composites in the marine environment
Modern structures are being exposed to severe environments and the lack of durability is one of the most serious problems in concrete infrastructures. Structural concrete exposed to marine environment deserves special attention as the sea salts chemically react with the cement matrix and the steel reinforcement which results in loss of strength, cracking, spalling, etc. The challenges of Civil Engineering, especially within the structures in extreme environments, pose considerable expectations with regards to the development of fibre reinforced materials for the development of more resistant and durable solutions.
In the present work, the behaviour of an Engineered Cementitious Composite (ECC) was studied. All the specimens prepared were cured in 4 types of environments: exposed to air (20ºC of temperature and 60% of humidity) immersed in tap water, immersed in salted water and immersed in seawater, all at an average temperature of 18ºC. A series of experiments, including compressive and direct tension tests were carried out to characterize the mechanical properties of the ECC materials while exposed to different environments.
The most important characteristic of ECC, which include multiple-cracking behaviour at increasing tensile strains when subjected to increasing tensile loading, was confirmed in all types of curing environments. In all cases the cementitious composites performed well with regards to the strain hardening behaviour typically observed in these materials, although the cracking processes have shown different characteristics. Due to the ability of the material to control crack opening below extremely low values, typically under 100 µm, the durability of structures can be significantly improved when ECC materials are used in the in marine environments. It was shown also that the salted water does not represent well the effect of seawater while characterising ECC mechanical characteristics in the laboratory.The authors acknowledge the material suppliers Secil, Civitest, Sika, Saint-Gobain (Fibraflex) and Eurocálcio – Calcários e Inertes SA for providing the materials used in this study
Creation of a vehicular delay-tolerant network prototype
Vehicular Delay-Tolerant Network (VDTN) is a new disruptive network architecture where vehicles act as the communication infrastructure. VDTN follows a layered architecture based on control and data planes separation, and positioning the bundle layer under the network layer. VDTN furnishes low-cost asynchronous communications coping with intermittent and sparse connectivity, variable delays and even no end-to-end connection. This paper presents a VDTN prototype (testbed) proposal, which implements and validates the VDTN layered architecture considering the proposed out-of-band signaling. The main goals of the prototype are emulation, demonstration, performance evaluation, and diagnose of protocol stacks and services, proving the applicability of VDTNs over a wide range of environments.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Covilhã Delegation, Portugal in the framework of the VDTN@Lab Project, and by the Euro-NF Network of Excellence from the Seventh Framework Programme of EU
Strategic environmental assessment in Tróia (Portugal)
Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 91-98Over the last two decades, the Tróia peninsula (SW coast of Portugal) has been designated by the Portuguese authorities both as a protected area and as an area of tourism development. The private investor that took over the tourism developments in Tróia asked the Institute of Marine Research (IMAR) to undertake an SEA, to help frame
the design and management of the future resort. SEA results were changed by local/central government decisions,
granting “more” than stakeholder/owner’s proposal, in terms of loads and densities. This process, as well as the main
characteristics and results of the SEA, are presented and discussed
Analysis of the oxypropylation process of a lignocellulosic material, almond shell, using the response surface methodology (RSM)
info:eu-repo/semantics/publishedVersio
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