Nano-calciumphosphate generation with novel surface and chemical features for improvement of cell activity in bone repair and replacement

Ideal biomaterial for bone replacement implanted should be resorbed by osteoclasts, while osteoblastic activity deposits new bone. Electrospun biphasic nanobioceramic scaffolds were synthesized for in vitro testing, contributing to bone tissue engineering.This paper was initially delivered at the Annual Congress of the Biological Sciences Division of the South African Academy for Science and Art, ARC-Plant Protection Research Institute, Roodeplaat, Pretoria, South Africa on 01 October 2010.http://www.satnt.ac.zaam2014ay201

Calciumphosphate scaffolds for bone tissue repair and applications – in vitro characterisation

The purpose of this study was to generate electrospun biphasic nanobioceramic scaffolds for in vitro testing, ultimately contributing to bone tissue engineering.This abstract was initially presented at the annual Biological Sciences Symposium, presented under the protection of the Suid-Afrikaanse Akademie vir Wetenskap en Kuns. The symposium was held at the University of Johannesburg on 01 October 2011.http://www.satnt.ac.z

Reliability and realizability risk evaluation of concept designs

This thesis addresses the improvement in quality of decision making in design through the use of decomposed design evaluation. The research reported in this thesis is supported by the Design Research Methodology. To perform decomposed decision making, it is necessary to identify criteria that are deemed important for this activity. Questionnaire surveys, literature review and interviews with industry helped to identify these criteria. Reliability and realizability are two criteria that are selected for research in this thesis. The questionnaire surveys are discussed in chapter 2. A review of literature on decision making, reliability and realizability is reported in chapters 3 and 4. Methodologies for evaluating reliability and physical realizability are discussed in chapter 5. Relative reliability risk assessment methodology is applied to various examples consisting of university and industry projects in chapter 6. The application helps to reveal the strengths of the methodology and is termed ‘Verification of the methodology’. Validation issues of both the methodologies are dealt with in chapter 7 using the controlled experimental design. It is found that both the methodologies help to improve the quality of decision making during design evaluation. Relative reliability risk evaluation methodology helps to improve the quality of decision making to a substantial extent but physical realizability evaluation methodology shows only a little improvement in quality of decision making. Finally, it is suggested that the decomposed design evaluation methodology helps to improve the quality of decision making and is therefore proposed to be used by both novice and experienced designers.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Submarine Cascais Canyon as a sediment conduit to the deep sea : comparison with adjacent slopes

Submarine canyons are known to be important conduits that trap, accumulate and deliver both natural and anthropogenic sediments from the shelf to the deep sea. Ten multi-cores from the Cascais Canyon and from the neighbour slopes (off Estremadura and Sines) were dated by 21Opb methodologies and analyzed for texture, major and trace metals to evaluate the role of submarine canyons in the transport of anthropogenic metals to the abyssal plains. Higher accumulation mass rates were determined in the upper Cascais Canyon than in the lower canyon and slopes. Enrichment factors (EF) were used to evaluate the level of metal enrichment in the studied areas. EF values exceeding natural background concentrations were obtained for Pb suggesting an anthropogenic and/or diagenetic source for Pb enrichment in the Cascais Canyon, but also, to a lesser extent, in the Estremadura and Sines slopes. Studies of provenance based on the ratio of different stable Pb isotopes can help to determinethe origin of such metal in the sediments

In vitro osteoclast-like and osteoblast cells' response to electrospun calcium phosphate biphasic candidate scaffolds for bone tissue engineering

Successful long term bone replacement and repair remain a challenge today. Nanotechnology has makes it possible to alter materials’ characteristics and therefore possibly improve on the material itself. In this study, biphasic (hydroxyapatite/β-tricalcium phosphate (HA/β-TCP)) nanobioceramic scaffolds were prepared by the electrospinning technique in order to mimic the extracellular matrix (ECM). Scaffolds were characterised by scanning electron microscopy (SEM) and Attentuated Total Reflectance Fourier Transform Infrared (ATRFTIR). Osteoblasts as well as monocytes that were differentiated into osteoclast-like cells, were cultured separately on the biphasic bioceramic scaffolds for up to 6 days and the proliferation, adhesion and cellular response were determined using lactate dehydrogenase (LDH) cytotoxicity assay, nucleus and cytoskeleton dynamics, analysis of the cell cycle progression, measurement of the mitochondrial membrane potential and the detection of phosphatidylserine expression. SEM analysis of the biphasic bioceramic scaffolds revealed nano fibers spun in a mesh-like scaffold. Results indicate that the biphasic bioceramic electrospun scaffolds are biocompatible and have no significant negative effects on either osteoblasts or osteoclast-like cells in vitro.Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa.http://www.springer.com/materials/journal/10853hb201

Alterações recentes nas razões isotópicas de Pb em sedimentos do Canhão Submarino de Cascais, Portugal

Temporal variations in lead concentrations and stable lead isotopic ratios in two sediment cores from the Cascais Canyon shows changes in sources of Pb during the last two centuries. The increase of total Pb contents wIth the evolution of Pb ratio recorded in both cores reveals the Increase of Pb from industrial sources. Nevertheless, this increase is lower in deeper core location (252-32) due to dilution and mixing with uncontaminated marine materials. An isotopic shift towards lower Pb/Pb in the shallower core (252-35) during the 1970s may reflect the increasing number of vehicles in the Lisboa area during that time

HFOB 1.19 osteoblast cells grown on a biomimetic biphasic nanoscaffold : an in vitro evaluation for possible bone tissue engineering

Much research over the past five decades has focussed on the repair and replacement of bone. Recently, the research focus has shifted to nanotechnology since it provides a platform from which to alter and possibly improve materials’ properties. In this study we have made use of previously developed electrospun biphasic nanoscaffolds to culture osteoblast cells on, and investigate specific responses of the cells towards the scaffolds. Osteoclast-like cells and osteoblast cells were cultured separately on the nanoscaffolds and the proliferation, adhesion and cellular response were determined. In this study, the mineralisation of the osteoblast cells was observed in a time study. The intracellular calcium ion concentration and nitric oxide concentration were determined in vitro while the cells were proliferating on the scaffolds. The expression of endothelial and inducible nitric oxide synthase was determined immunohistochemically. Quantitative data were obtained from fluorometer studies. Qualitative data was supplied by light- and fluorescent confocal microscopy. During studies with microscopy, a minimum of five representative images from each sample were captured. The cells showed increased mineralisation over time. An increase in intracellular Ca2+ was not observed when compared to the controls. However, an increase in intracellular nitric oxide formation was detected. Expression of endothelial nitric oxide synthase but not inducible nitric oxide synthase was detected in vitro. From the results we can conclude that the scaffolds are biocompatible and conducive to healthy cell growth and differentiation and could possibly be applied in non-load-bearing bone regeneration and repair applications.http://www.biomedres.infoam2019Physiolog

The Photometric and Kinematic Structure of Face-On Disk Galaxies. I. Sample Definition, H-alpha Integral Field Spectroscopy, and HI Line-Widths

We present a survey of the photometric and kinematic properties of 39 nearby, nearly face-on disk galaxies. Our approach exploits echelle-resolution integral-field spectroscopy of the H-alpha regions, obtained with DensePak on the WIYN 3.5m telescope Bench Spectrograph. This data is complemented by HI line-profiles observed with the Nancay radio telescope for 25 of these sample galaxies. Twelve additional line-widths are available for sample galaxies from the literature. In this paper, we introduce the goals of this survey, define the sample selection algorithm, and amass the integral field spectroscopic data and HI line-widths. We establish spatially-integrated H-alpha line-widths for the sample. We test the veracity of these spatially-integrated line profiles by convolving narrow-band imaging data with velocity field information for one of the sample galaxies, PGC 38268, and also by comparing to HI line profiles. We find HI and H-alpha line profiles to be similar in width but different in shape, indicating we are observing different spatial distributions of ionized and neutral gas in largely axisymmetric systems with flat outer rotation-curves. We also find vertical velocity dispersions of the ionized disk gas within several disk scale-lengths have a median value of 18 km/s and an 80% range of 12-26 km/s. This is only a factor of ~2 larger than what is observed for neutral atomic and molecular gas. With standard assumptions for intrinsic and thermal broadening for H-alpha, this translates into a factor of three range in turbulent velocities, between 8 and 25 km/s.Comment: 29 pages, 20 figures; accepted for publication in ApJ Supplement Serie

Cluster temporal de metales en un testigo corto de sedimento del Cañón Submarino de Cascais (Margen de Portugal)

The Cascais Canyon delivers contaminated sediments from the shelf to the deep marine environment. Multi-core PE252-32, located at 2100 m water depth in the canyon, records the latest 300 years of sedimentation. It was dated by 210Pb and analyzed texturally and geochemically for major elements and selected trace metals (Cu, Cr, Hg, Li, Ni, Pb and Zn). Cluster analysis performed on the down-core geochemical data identified four groups of variables related by grain-size, geochemical source and composition. Mercury, Pb and Zn were grouped in a cluster representing the anthropogenic component. Cluster analysis was applied again particularly to the latter cluster relatively to depth, in order to constrain the onset and temporal evolution of anthropogenic contamination. A second clustering, made on the basis of Hg, Pb and Zn, grouped samples by age and degree of anthropogenic contamination. One cluster contained relatively uncontaminated samples older than 1900 AD, and another cluster samples younger than 1900 AD with distinct metal enrichment. Maximum enrichments occurred during the early 1980s, followed by a slight recovery from the mid-1980s to the present. Mercury was the element with the highest enrichment factor (EFHg=5). Despite relatively low accumulation rates at this core location, our results show the importance of the Cascais Canyon as a transport route for contaminated sediments from the Tagus prodelta into the deep regions of the Portuguese Margin.El Cañón submarino de Cascais distribuye sedimentos contaminados de la plataforma continental al medio marino profundo. El testigo PE252-32, situado a 2100 metros de profundidad dentro del cañón, registra los últimos 300 años de su sedimentación. Se ha datado con 210Pb y ha sido analizada su granulometría, elementos mayoritarios y traza (cobre, cromo, mercurio, litio, níquel, plomo y zinc). Se ha llevado a cabo un análisis estadístico clúster, inicialmente aplicado a las series de datos geoquímicos en función de la profundidad, identificándose 4 grupos de variables, relacionados por la granulometría, procedencia y composición geoquímica. Los metales mercurio, plomo y zinc aparecen agrupados en un clúster que representa la componente antropogénica. A continuación el mismo análisis estadístico se aplicó específicamente a este grupo, en función de la profundidad, organizando las muestras según la edad de contaminación antropogénica. Como resultado las muestras quedan agrupadas en dos clústers principales, el de las muestras no contaminadas y más antiguas de 1900 AC, y el de las muestras más recientes de 1900 AC, marcando esta fecha el inicio de la contaminación por impacto de la actividad humana. Los máximos enriquecimientos ocurren durante el inicio de la década de los años ochenta, seguidos de un ligero descenso a partir de mediados de la misma década hasta la actualidad. De entre los demás, el mercurio es el elemento con el mayor grado de enriquecimiento (EFHg=5). Aunque la tasa de acumulación de sedimentos en este lugar es relativamente baja, los resultados obtenidos ponen en evidencia la importancia del Cañón submarino de Cascais como vía de transporte de sedimentos contaminados depositados en el pro-delta del Tajo a las regiones profundas del margen de Portugal

The certification of the mass fraction of carbon in cementite grains in a Fe-C matrix: IRMM-471

The report describes the production and certification of IRMM-471, a reference material certified for the carbon mass fraction of its cementite (Fe3C) grains. The Fe3C grains are dispersed within an iron pearlite matrix and present an average grain diameter between 20 µm and 50 μm. IRMM-471 has been produced and certified in order to be used as calibrant in electron probe micro-analyser (EPMA) for carbon determination in iron and steel products.JRC.D.2-Standards for Innovation and sustainable Developmen