University of Minho

About: University of Minho is a education organization based out in Braga, Portugal. It is known for research contribution in the topics: Context (language use) & Population. The organization has 10585 authors who have published 34736 publications receiving 732436 citations. The organization is also known as: Universidade do Minho & UMinho.

Fluorinated polymers as smart materials for advanced biomedical applications

Abstract: Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.

Osteogenic Induction of Human Bone Marrow-Derived Mesenchymal Progenitor Cells in Novel Synthetic Polymer–Hydrogel Matrices

Abstract: The aim of this project was to investigate the in vitro osteogenic potential of human mesenchymal progenitor cells in novel matrix architectures built by means of a three-dimensional bioresorbable synthetic framework in combination with a hydrogel. Human mesenchymal progenitor cells (hMPCs) were isolated from a human bone marrow aspirate by gradient centrifugation. Before in vitro engineering of scaffold-hMPC constructs, the adipogenic and osteogenic differentiation potential was demonstrated by staining of neutral lipids and induction of bone-specific proteins, respectively. After expansion in monolayer cultures, the cells were enzymatically detached and then seeded in combination with a hydrogel into polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) frameworks. This scaffold design concept is characterized by novel matrix architecture, good mechanical properties, and slow degradation kinetics of the framework and a biomimetic milieu for cell delivery and proliferation. To induce osteogenic differentiation, the specimens were cultured in an osteogenic cell culture medium and were maintained in vitro for 6 weeks. Cellular distribution and viability within three-dimensional hMPC bone grafts were documented by scanning electron microscopy, cell metabolism assays, and confocal laser microscopy. Secretion of the osteogenic marker molecules type I procollagen and osteocalcin was analyzed by semiquantitative immunocytochemistry assays. Alkaline phosphatase activity was visualized by p-nitrophenyl phosphate substrate reaction. During osteogenic stimulation, hMPCs proliferated toward and onto the PCL and PCL-HA scaffold surfaces and metabolic activity increased, reaching a plateau by day 15. The temporal pattern of bone-related marker molecules produced by in vitro tissue-engineered scaffold-cell constructs revealed that hMPCs differentiated better within the biomimetic matrix architecture along the osteogenic lineage.

Exporting barriers: Insights from Portuguese small- and medium-sized exporters and non-exporters

Abstract: This study aimed to identify some of the major barriers that may hinder potential exporters and non-exporters from exporting their operations. Both parametric and semi-parametric binary choice models were used to analyze the data with the aim of assessing which of the major barriers detected can better explain the surveyed SMEs' decision to export or not. Six out of the 23 distinct barriers defined initially in the survey were found as statistically significant determiners of the probability that a surveyed SME firm would be a non-exporter. If public agents are interested in promoting and implementing the most effective mechanisms to stimulate exporting of domestic firms, several policy measures are advisable in order to minimize or alleviate the perceived inhibiting impact of barriers on SME firms' exporting decisions. In summary, results from the study revealed that non-exporters consider the lack of knowledge of potential markets, lack of qualified export personnel, lack of technical suitability, degree of competition in the sector, lack of financial assistance (governmental and financial institutions), and lack of qualified human resources as the main export barriers. By comparison, exporters perceived warehousing and control of the physical product flow in the target market to be the biggest barrier.