948 research outputs found

    Close-to-native bone repair via tissue-engineered endochondral ossification approaches

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    In order to solve the clinical challenges related to bone grafting, several tissue engineering (TE) strategies have been proposed to repair critical-sized defects. Generally, the classical TE approaches are designed to promote bone repair via intramembranous ossification. Although promising, strategies that direct the osteogenic differentiation of mesenchymal stem/stromal cells are usually characterized by a lack of functional vascular supply, often resulting in necrotic cores. A less explored alternative is engineering bone constructs through a cartilage-mediated approach, resembling the embryological process of endochondral ossification. The remodeling of an intermediary hypertrophic cartilaginous template triggers vascular invasion and bone tissue deposition. Thus, employing this knowledge can be a promising direction for the next generation of bone TE constructs. This review highlights the most recent biomimetic strategies for applying endochondral ossification in bone TE while discussing the plethora of cell types, culture conditions, and biomaterials essential to promote a successful bone regeneration process.publishe

    An analysis of the potentialities of portuguese vernacular architecture to improve energy efficiency

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    Vernacular architecture is characterised by a type of formal expression that has been developed in response to a number of factors â climatic, lithologic, cultural and economic â characterising the local area or region. In its various forms, a range of techniques has been employed in different regions to mitigate the effects of climate. Despite the fact that Portugal is a small country, it has a territory full of contrasts, which gave origin to many different architectural manifestations. The approaches adopted in the design and construction of vernacular buildings have the potential for further development and could be adapted in response to contemporary needs. In the future, a blend of tradition and modernity should be aimed at in order to develop a new form of aesthetics and functional construction. Portuguese vernacular architecture is associated with a fund of valuable knowledge that should be studied and aligned with the principles of sustainability. In this paper, is presented the climatic contrast between the northern and southern parts of Portugal and the relation with the purpose of different passive solar techniques used in vernacular architecture to provide comfort. The focus is on the effectiveness of passive cooling techniques (e.g. high thermal inertia, the use of light colours and patios), and the findings of a case study in which the thermal performance during the summer of a vernacular residential building located in the south of Portugal are presented. In the context of the current global drive for clean energy and sustainable buildings, much can be learned from a review of past experience in order to provide an understanding of such forms of construction, which are an intrinsic feature of specific places and have evolved over time in the face of a lack of resources

    Photocatalytic Bi2O3/TiO2:N thin films with enhanced surface area and visible light activity

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    Bi2O3 nanocone films functionalized with an overlayer of TiO2 were deposited by d.c. reactive magnetron sputtering. The aforementioned nanocone structures were formed via a vapour-liquid-solid (VLS) growth, starting from a catalytic bismuth seed layer. The resultant nanocones exhibit an improved surface area, measured by atomic force microscopy, when compared to non-VLS deposition of the same metal oxide. X-ray diffraction texture analysis enabled the determination of the crystallographic β-phase of Bi2O3. A very thin TiO2 overlayer (6 nm thick), undoped and doped with nitrogen, was deposited onto the nanocones template, in order to functionalize these structures with a photocatalytic, self-cleaning, cap material. N-doped TiO2 overlayers increased the selective absorption of visible light due to nitrogen doping in the anatase cell, thus, resulting in a concomitant increase in the overall photocatalytic efficiency.The authors acknowledge the financial support of the project “NANOPURIFY—Development of photocatalytic panels for air treatment units, Vieira & Lopes Lda.”, with the reference 024121, co-funded by the European Regional Development Fund (ERDF), through the Operational Programme for Competitiveness and Internationalisation (COMPETE 2020), under the PORTUGAL 2020 Partnership Agreement. Filipe C. Correia acknowledges the financial support from the Fundação para a Ciência e Tecnologia (FCT) for the Ph.D grant SFRH/BD/111720/2015

    Interstitial deletion on chromosome 14q in prenatal diagnosis

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    A limited number of prenatal diagnosis (PND) cases have reported interstitial deletions of the long arm of chromosome 14 involving the 14q31-32 region. Those cases presented cardiac anomalies, urogenital anomalies, congenital diaphragmatic hernia, and mild pyelectasis. We report the PND of a 33-year-old pregnant woman, who underwent chorionic villus sampling at 12 weeks of gestation after a positive combined 1st trimester screen. The karyotype revealed a 14q interstitial deletion. Amniocentesis was performed at 18 weeks of gestation to confirm the deletion and to exclude a confined placental mosaicism and a microarray analysis was performed in order to accurately define the deletion breakpoints. Cytogenetics analysis revealed a karyotype 46,XY,del(14)(q31q32.2)dn. Microarray analysis allowed to redefined the breakpoints accurate localization and the identification of a ~21Mb deletion (arr[hg19] 14q31.1q32.31(79917376_101568230)x1). At 18 weeks of gestation the fetus presented abnormal fetal biometric parameters (occipitofrontal diameter, cephalic perimeter and abdominal circumference) on ultrasound. After counseling the couple opted for pregnancy termination. The postmorten analysis presented decreased biometry, low weight and low fetal size, facial dysmorphism, clinodactyly, club foot, overlapping fingers and short penis. In internal habitus he presented thymus hypoplasia, bladder hypoplasia, and horseshoe kidneys. The genotype-phenotype correlation in PND pure del(14q) cases is not well established. Furthermore, to our knowledge, del(14q) had not been reported so early in the gestation yet. In this case the positive 1st trimester screen was related to the inverted ductus venosus and low PAPP-A value. The urogenital anomalies (as horseshoe kidneys) and biometry anomalies are described in the literature. However, to our knowledge, some features of the present case were not seen in other reported cases, for instance clinodactyly, club foot, overlapping fingers, thymus hypoplasia and bladder hypoplasia. Other reports described cardiac and cerebral anomalies, diaphragmatic hernia, and also UPD(14)like phenotypes, which are possibly liked to the 14q32 imprinted region. The establishment of a phenotype-genotype correlation is difficult given the size of the deletion, which includes a large number of genes in distinct regions. Nevertheless, this work contributes to a better identification of additional features associated to del(14q) that can be present in PND.info:eu-repo/semantics/publishedVersio

    Advances in bioprocessing, analytics and formulation of influenza HA-VLP vaccine candidates produced by insect cells

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    The emergence of new influenza strains demands the continued development of novel, flexible, and scalable platforms for vaccine production. In this study, we describe advancements in the manufacturing process of influenza hemagglutinin (HA)-displaying virus-like particle (VLP)-based vaccines produced by insect cells, from upstream and downstream processing to analytics and formulation. Aiming to improve influenza HA-VLPs production, evolutionary engineering and process intensification have been applied. Adaptation of stable Sf-9 cells producing HA-VLPs to hypothermic growth resulted in up to 12-fold higher expression. Likewise, adaptation of parental High Five cells to neutral pH induced a 3-fold higher specific HA-VLPs production rate following infection with baculovirus. In both case studies, the adaptation process had no impact on VLPs activity and morphology. Noteworthy, stable adapted Sf-9 cells could be cultured in perfusion (up to 100x106 cell/mL) and continuous (~20x106 cell/mL) operation modes with cell-specific productivity similar to batch mode. Please click Download on the upper right corner to see the full abstract

    SWIMMING BIOPHYSICAL RELEVANT PARAMETERS EXTRACTED FROM VELOCIMETRY AND ACCELEROMETRY

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    This paper presents different examples of the use of direct velocimetry and accelerometry for the biophysical evaluation and advice of swimmers, assessing relevant parameters for performance enhancement. The described techniques are easy to build and operate, and allow real-and useful-time feedback for practitioners. The velocimetric measurements were based on a cable speedmeter (SwimSensor), and the accelerometric ones using a 3-axial inertial central –WIMU –, incorporating both accelerometers and gyroscopes. Results include swimming intracyclic velocity fluctuations for technical feedback, spectral analysis of the v(t) function to depict bioenergetical anaerobic intensity zones transition and specific fatigue, and breaststroke gliding drag assessment using inverse dynamics
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