Xing Z.,University of Bergen |
Pedersen T.O.,University of Bergen |
Wu X.,Innsbruck Medical University |
Xue Y.,University of Bergen |
And 7 more authors.
Tissue Engineering - Part A | Year: 2013
Significant evidence has indicated that poly(L-lactide)-co-(É"- caprolactone) [(poly(LLA-co-CL)] scaffolds could be one of the suitable candidates for bone tissue engineering. Oxygen-terminated nanodiamond particles (n-DP) were combined with poly(LLA-co-CL) and revealed to be positive for cell growth. In this study, we evaluated the influence of poly(LLA-co-CL) scaffolds modified by n-DP on attachment, proliferation, differentiation of bone marrow stromal cells (BMSCs) in vitro, and on bone formation using a sheep calvarial defect model. BMSCs were seeded on either poly(LLA-co-CL)- or n-DP-coated scaffolds and incubated for 1 h. Scanning electron microscopy (SEM) and fluorescence microscopy were used in addition to protein and DNA measurements to evaluate cellular attachment on the scaffolds. To determine the effect of n-DP on proliferation of BMSCs, cell/scaffold constructs were harvested after 3 days and evaluated by Bicinchoninic Acid (BCA) protein assay and SEM. In addition, the osteogenic differentiation of cells grown for 2 weeks on the various scaffolds and in a dynamic culture condition was evaluated by real-time RT-PCR. Unmodified and modified scaffolds were implanted into the calvaria of six-year-old sheep. The expression of collagen type I (COL I) and bone morphogenetic protein-2 (BMP-2) after 4 weeks as well as the formation of new bone after 12 and 24 weeks were analyzed by immunohistochemistry and histology. Scaffolds modified with n-DP supported increased cell attachment and the mRNA expression of osteopontin (OPN), bone sialoprotein (BSP), and BMP-2 were significantly increased after 2 weeks of culture. The BMSCs had spread well on the various scaffolds investigated after 3 days in the study with no significant difference in cell proliferation. Furthermore, the in vivo data revealed more positive staining of COL I and BMP-2 in relation to the n-DP-coated scaffolds after 4 weeks and presented more bone formation after 12 and 24 weeks. n-DP modification significantly increased cell attachment and differentiation of BMSCs on poly(LLA-co-CL) scaffolds in vitro and enhanced bone formation in vivo. © 2013, Mary Ann Liebert, Inc. Source
Agency: Cordis | Branch: FP7 | Program: BSG-SME | Phase: SME-1 | Award Amount: 1.15M | Year: 2009
Aerospace has been pioneer in the industrial manufacturing of fibre reinforced composites for high performance components. Composite materials are used extensively as their higher specific properties (properties per unit weight) of strength and stiffness, when compared to metals, offer interesting opportunities for new product design. Still nowadays it is a growing market due to the technical improvements in the properties of the fibres, allowing the substitution of other materials like aluminium. It is remarkable the case of Boeings new 787 jet, where 35 tons (50% of total weight) of fibre reinforced composites are being used for each jet. By comparison, the 777 aircraft, currently Boeings most advanced passenger jet, only has 12% composites. Aerospace sector expects that the high use of composites will reduce maintenance time and expense and cut fuel burn per passenger by 20%. However, being nonhomogeneous, anisotropic and reinforced by very abrasive components, these materials are difficult to machine. Significant damage to the workpiece may be introduced and high wear rates of the cutting tools are experienced. One added problem related with the machining of composite materials is the operator safety, as instead of chips, the machining of composite produces small particles and dust in the range of 0,5 micrometres to 20 micrometres. These residues are harmful for human beings if aspirated because of their carcinogenic potential. Therefore, these residues must be controlled to avoid the hazards they can provoke. The main objective of ASPIRATE is to develop a new machining technology for carbon and glass fibre reinforced plastic (CFRP and GFRP) parts based on the internal extraction of the produced chip and dust particles through the whole machining system (cutting tool, tool holder, spindle). This innovative machining system will allow the safe, dry and clean machining of CFRP and GFRP, opening a growing and profitable market to the SMEs involved in the project.
Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-ITN-2008 | Award Amount: 2.14M | Year: 2009
There is a consensus today that supplying a growing world population with energy is one of the biggest if not the biggest challenge mankind is facing in the 21st century. The reasons for this are numerous and are among others related to the observation that energy is critical to human development, including economic growth, equity and employment, and that fossil fuels our current energy backbone are slowly but inevitably declining. This generates an increasing demand of well-educated young scientists knowledgeable in materials science for energy conversion and storage, because a central problem for all forms of energy is their efficient generation or conversion as well as energy storage with sufficiently high density (e.g., hydrogen or biofuels). In this broader context, the proposed Marie Curie Initial Training Network (ITN) MATCON will concentrate on the following topics of fundamental importance: Photo-electrochemical generation of hydrogen by water splitting Bio-inspired and biomimetic energy conversion Thermoelectric and thermoionic heat conversion For all of these topics, alternative or new materials and materials combinations will be necessary to improve the efficiency of energy conversion or to overcome existing problems with stability. Therefore, the Network will also put considerable emphasis on the tailoring and development of specific materials for electrodes, substrates and functional interfaces. This expertise will be of central importance for the successful implementation of the different research topics outlined above and, at the same time, provide an ideal basis for the training of the young researchers in state of the art materials science and semiconductor technology.
Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: NMP-2008-3.2-2 | Award Amount: 3.41M | Year: 2009
The European manufacturing industry is currently facing the challenge of reducing production costs and times while increased product quality. In order to achieve this, the industry must develop new, innovative machining concepts beyond the current state-of-the-art. Current process monitoring systems concentrate on the monitoring of forces, vibrations and acoustic emission as input signals, but do not consider tool temperature. Tool temperature does however have a significant influence on workpiece quality and tool wear and therefore on manufacturing productivity. The ConTemp project will develop a self-learning temperature monitoring system combined with a self-cooling tool. The system will control and stabilise tool temperature in the cutting process, which leads to longer tool lifetimes and increased part accuracies. Significant cost reductions can therefore be achieved, as well as allowing the machining of difficult-to-cut materials without incurring the larger costs typically associated with this. The system is based on the development of a combined sensor/actor system. By using an innovative micro cooling device a closed coolant circuit can be used for the measurement of the tool temperature, and by variation of the coolant flow the temperature can be controlled. A further significant advantage of the system is the possibility of avoiding the need for cooling lubricant. Diamond coatings on the surface of the self-cooling tool will ensure maximumheat dissipation from the tool tip, and so sufficient cooling can be achieved with the interior micro-cooling device to allow dry machining. The avoidance of cooling lubricant will lead to substantial cost reductions and environmentally friendly machining.
Sternschulte H.,TU Munich |
Staudinger I.,TU Munich |
Sepe A.,TU Munich |
Sepe A.,University of Cambridge |
And 5 more authors.
Diamond and Related Materials | Year: 2013
In this work, an ultrananocrystalline diamond film was studied with grazing-incidence small-angle X-ray scattering (GISAXS) to determine the diamond grain size and average distance of the grains with a non-destructive method and with excellent sampling statistics. The measured 2D GISAXS patterns were modelled with the assumption of monodisperse spheres. The best fits were obtained with the «buried layer» model where the spheres are correlated within the film plane. This correlation was approximated with a two-dimensional Percus-Yevick structure factor. The average diamond grain size of D = 8.0-8.5 nm and a centre-to-centre distance of the grains with 10.4-11.9 nm agrees well with transmission electron microscopy results of comparable samples. © 2013 Elsevier B.V. Source