Supercritical phase inversion of starch-poly(e-caprolactone) for tissue engineering applications

In this work, a starch-based polymer, namely a blend of starch-poly(ε-caprolactone) was processed by supercritical assisted phase inversion process. This processing technique has been proposed for the development of 3D structures with potential applications in tissue engineering applications, as scaffolds. The use of carbon dioxide as non-solvent in the phase inversion process leads to the formation of a porous and interconnected structure, dry and free of any residual solvent. Different processing conditions such as pressure (from 80 up to 150 bar) and temperature (45 and 55°C) were studied and the effect on the morphological features of the scaffolds was evaluated by scanning electron microscopy and micro-computed tomography. The mechanical properties of the SPCL scaffolds prepared were also studied. Additionally, in this work, the in vitro biological performance of the scaffolds was studied. Cell adhesion and morphology, viability and proliferation was assessed and the results suggest that the materials prepared are allow cell attachment and promote cell proliferation having thus potential to be used in some for biomedical applications.Ana Rita C. Duarte is grateful for financial support from Fundacao para a Ciencia e Tecnologia through the grant SFRH/BPD/34994/2007

Supercritical fluid technology as a tool to prepare gradient multifunctional architectures towards regeneration of osteochondral injuries

Platelet lysates (PLs) are a natural source of growth factors (GFs) known for its stimulatory role on stem cells which can be obtained after activation of platelets from blood plasma. The possibility to use PLs as growth factor source for tissue healing and regeneration has been pursued following different strategies. Platelet lysates are an enriched pool of growth factors which can be used as either a GFs source or as a three-dimensional (3D) hydrogel. However, most of current PLs-based hydrogels lack stability, exhibiting significant shrinking behavior. This chapter focuses on the application of supercritical fluid technology to develop three-dimensional architectures of PL constructs, crosslinked with genipin. The proposed technology allows in a single step operation the development of mechanically stable porous structures, through chemical crosslinking of the growth factors present in the PL pool, followed by supercritical drying of the samples. Furthermore gradient structures of PL-based structures with bioactive glass are also presented and are described as an interesting approach to the treatment of osteochondral defects.info:eu-repo/semantics/publishedVersio

Production of electrospun fast-dissolving drug delivery systems with therapeutic eutectic systems encapsulated in gelatin

Fast-dissolving delivery systems (FDDS) have received increasing attention in the last years. Oral drug delivery is still the preferred route for the administration of pharmaceutical ingredients. Nevertheless, some patients, e.g. children or elderly people, have difficulties in swallowing solid tablets. In this work, gelatin membranes were produced by electrospinning, containing an encapsulated therapeutic deep-eutectic solvent (THEDES) composed by choline chloride/mandelic acid, in a 1:2 molar ratio. A gelatin solution (30% w/ v) with 2% (v/v) of THEDES was used to produce electrospun fibers and the experimental parameters were optimized. Due to the high surface area of polymer fibers, this type of construct has wide applicability. With no cytotoxicity effect, and showing a fast-dissolving release profile in PBS, the gelatin fibers with encapsulated THEDES seem to have promising applications in the development of new drug delivery systems.The research leading to these results has received funding from Fundação para a Ciência e a Tecnologia (FCT) through the projects ENIGMA - PTDC/EQU-EPR/ 121491/2010 and UID/CTM/50025/2013, LAQVREQUIMTE: UID/QUI/50006/2013, UCIBIO-REQUIMTE: UID/Multi/04378/2013 (co-financed by the ERDF under the PT2020 Partnership Agreement [POCI-01-0145-FEDER- 007728]) and by FEDER through the COMPETE 2020 Programme. Marta Martins is grateful for financial support from FCT through the grant BIM/PTDC/EQUEPR/121491/ 2010/ENIGMA. This research has also received funding from the European Union Seventh Framework Programme (FP7/ 2007-2013) under grant agreement number REGPOTCT2012-316331-POLARIS and from the project BNovel smart and biomimetic materials for innovative regenerative medicine approaches^ RL1 - ABMR - NORTE-01-0124- FEDER-000016) co-financed by North Portugal Regional Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Evaluation of Senior Brazilian Dental Students About Mouth Preparation and Removable Partial Denture Design

This study aimed to evaluate the knowledge of senior dental students about mouth preparation and removable partial denture (RPD) design Two hundred sixty six senior students from eleven dental schools in the State of Sao Paulo, Brazil, comprised the sample The subjects examined two partially edentulous casts mounted on a semiadjustable articulator, answered a questionnaire regarding the treatment plan and drew the RPD design The casts consisted of Kennedy Class III, modification 1 maxillary arch and Class II mandibular arch Ninety percent of the students believed that mouth preparation should be performed although no one was able to name all necessary procedures For the maxillary arch 12 percent of the denture designs were completely appropriate, 51 percent were partially appropriate, and 37 percent were inappropriate For the mandibular arch, the results were 3 percent, 40 percent, and 57 percent, respectively74111255126

Soil characteristics in degraded area restoration at Reserva Biol\uf3gica de Po\ue7o das Antas, RJ.

O primeiro passo para garantir o sucesso da restaura\ue7\ue3o de uma \ue1rea degradada \ue9 restabelecer as taxas de ciclagem de nutrientes e os n\uedveis de mat\ue9ria org\ue2nica no solo. Para avaliar as altera\ue7\uf5es no solo em \ue1reas sob restaura\ue7\ue3o na Reserva Biol\uf3gica de Po\ue7o das Antas, foram coletadas amostras em \ue1reas de floresta madura, plantios mistos de esp\ue9cies arb\uf3reas nativas com 8 anos de vida e pastagens abandonadas, nas v\ue1rzeas e morrotes. O delineamento experimental foi o inteiramente casualizado. As amostras foram coletadas nas profundidades de 0-2,5 cm; 2-5-7,5 cm; e 7,5-20 cm, sendo avaliados o pH do solo e os teores de Al, Ca + Mg, P, K, C e N do solo. Os plantios da v\ue1rzea apresentaram teores de Ca + Mg, K, C e mat\ue9ria org\ue2nica do solo (MOS) superiores aos dos outros tratamentos, indicando o r\ue1pido estabelecimento de altas taxas de ciclagem de nutrientes e alta taxa de atividade biol\uf3gica. Os valores das bases troc\ue1veis foram mais altos para a camada mais superficial, pela maior proximidade com a serapilheira. A estabilidade do solo foi alta para todos os tratamentos que apresentaram rela\ue7\ue3o C:N abaixo de 12:1. Para estimar a forma como a MOS est\ue1 armazenada foi feito o fracionamento qu\uedmico pela obten\ue7\ue3o de extratos \ue1cidos e alcalinos, que apontou maior produ\ue7\ue3o de \ue1cidos f\ufalvicos (AF) e h\ufamicos (AH), e huminas (HU) no plantio de v\ue1rzea, para as tr\ueas profundidades de solo. O plantio no morrote apresentou maiores valores para a rela\ue7\ue3o (AF+AH)/HU, o que sugere uma menor estabilidade nesse tratamento. Os resultados indicam que os plantios t\ueam alto potencial para restabelecer as taxas de ciclagem de nutrientes e os teores de mat\ue9ria org\ue2nica do solo no curto prazo, e que as \ue1reas de morrote necessitam de t\ue9cnicas adicionais para acelerar o desenvolvimento dos plantios.A project to restore a degraded area must firstly reestablish organic soil matter and nutrient cycling process. In order to evaluate the influence of indigenous tree plantations on changings in soil fertility and organic matter dynamics, an experiment was installed at the Po\ue7o das Antas Biological Reserve, an Atlantic Rain Forest remnant of ca. 5,200. Six treatments involved mature forests (F), 8-year-old mixed plantations of indigenous tree species (P), and abandoned pastures (G), at both the flooding (V) and the sloping (M) areas of the Reserve. The experimental design was completely randomized. Soil samples were collected at the layers 0-2.5cm; 2-5-7.5cm; and 7.5-20cm to evaluate soil pH, and Al, Ca+Mg, P, K, C and N contents. The PV treatment showed higher values for the exchangeable c\ue1tions, C and soil organic matter (SOM) contents, indicating high cycling rates and biological activity. Soil stability was considered to be high in all treatments, since C:N ratio was lower than 12:1. Organic matter fragmentation showed a higher amount of fulvic acids (FA), humic acids (HA) and humin (HU) in the PV treatment, for the three soil layers. The plantation on the sloping areas (PM) showed the highest values of (FA+HA)/HU ratio, suggesting a lower stability condition. Results suggest indigenous tree plantations have great potential to restore nutrient cycling and soil organic matter contents in short term period in areas where forests have been converted into pastures. Techniques to accelerate the development of trees plantation on the sloping areas must be adopted