Developing Frameworks for School Self-Evaluation to Improve School Effectiveness for Peace in Northern Ireland

This article contributes towards redefining school improvement more broadly than conventional outcomes sometimes imply, and describes original and practical applications of school self-evaluation models. The significance of the work has been acknowledged by reviewers in the school improvement and peacebuilding and development fields. As a result of the research reported here, Smith was invited to support the work of the Department for Education Northern Ireland Schools Community Relations Panel and the Community Relations officers representing the five Education and Library Boards. The latter used the self-evaluation framework as a model for developing a regional whole-school self-evaluation document. Smith was the lead author of the paper.

High Reactivity of Metal-Organic Frameworks under Grinding Conditions: Parallels with Organic Molecular Materials

Interconversion made easy: Metal–organic frameworks (MOFs) are surprisingly reactive under grinding conditions and can perform various rearrangements (see picture). In this respect, the results reveal clear parallels between MOFs and organic molecular materials.

The effect of simvastatin on bone formation and ceramic resorption in a peri-implant defect model

Experimental use of statins as stimulators of bone formation suggests they may have widespread applicability in the field of orthopaedics. With their combined effects on osteoblasts and osteoclasts, statins have the potential to enhance resorption of synthetic materials and improve bone ingrowth. In this study, the effect of oral and local administration of simvastatin to a 0 tricalcium phosphate (beta TCP)-filled defect around an implant was compared with recombinant human bone morphogenetic protein 2 (rhBMP2). On hundred and sixty-two Sprague-Dawley rats were assigned to treatment groups: local application of 0.1, 0.9 or 1.7 mg of simvastatin, oral simvastatin at 5, 10 or 50 mg kg(-1) day(-1) for 20 days, local delivery of I or 10 mu g of rhBMP2, or control. At 6 weeks rhBMP2 increased serum tartrate-resistant acid phosphatase 5b levels and reduced PTCP area fraction, particle size and number compared with control, suggesting increased osteoclast activity. There was reduced stiffness and increased mechanical strength with this treatment. Local simvastatin resulted in a decreased mineral apposition rate at 6 weeks and increased fibrous area fraction, PTCP area fraction, particle size and number at 26 weeks. Oral simvastatin had no effect compared with control. Local application of rhBMP2 increased resorption and improved mechanical strength whereas simvastatin was detrimental to healing. Oral simvastatin was ineffective at promoting either ceramic resorption or bone formation. The effect of statins on the repair of bone defects with graft substitute materials is influenced by its bioavailability. Thus, further studies on the optimal delivery system are needed. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The effect of osteogenic growth factors on bone growth into a ceramic filled defect around an implant

Currently available synthetic bone substitutes perform poorly compared to autograft. It is hoped that by adding osteogenic growth factors to the materials, new bone formation could be increased and the clinical outcome improved. In this study, IGF-1, bFGF and TGFbeta1, alone and in combination, were absorbed onto a carrier of P-tricalcium phosphate (PTCP) and implanted into a defect around a hydroxyapatite-coated, stainless steel implant in the proximal tibia of rat in a model of revision arthroplasty. Animals were sacrificed at 6 and 26 weeks for routine histology and histomorphometry and mechanical push out tests. The results show that only bFGF had a significant effect on ceramic resorption. The groups that received bFGF and bFGF in combination with TGFbeta1 had smaller and fewer betaTCP particles remaining in the defect at 6 and 26 weeks. No growth factor combination significantly enhanced new bone formation or the mechanical strength of the implant. These results indicate that, of the growth factors tested, only bFGF had any beneficial effect on the host response to the implant, perhaps by delaying osteoblast differentiation and thereby prolonging osteoclast access to the ceramic. (C) 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

Bone growth into a ceramic-filled defect around an implant - The response to transforming growth factor beta 1

Synthetic bone substitutes provide an alternative to autograft but do not give equivalent clinical results. Their performance may be enhanced by adding osteogenic growth factors. In this study, TGFbeta1 was absorbed on to a carrier of 0 tricalcium phosphate and Gelfoam(R) and used to fill a defect around a tibial implant in a rat model of revision arthoplasty.

The relationship between cement fatigue damage and implant surface finish in proximal femoral prostheses

The majority of cemented femoral hip replacements fail as a consequence of loosening. One design feature that may affect loosening rates is implant surface finish. To determine whether or not surface finish effects fatigue damage accumulation in a bone cement mantle, we developed an experimental model of the implanted proximal femur that allows visualisation of damage growth in the cement layer. Five matt surface and five polished surface stems were tested. Pre-load damage and damage after two million cycles was measured. Levels of pre-load (shrinkage) damage were the same for both matt and polished stems; furthermore damage for matt vs. polished stems was not significantly different after two million cycles. This was due to the large variability in damage accumulation rates. Finite element analysis showed that the stress is higher for the polished (assumed debonded) stem, and therefore we must conclude that either the magnitude of the stress increase is not enough to appreciably increase the damage accumulation rate or, alternatively, the polished stem does not debond immediately from the cement. Significantly (P = 0.05) more damage was initiated in the lateral cement compared to the medial cement for both kinds of surface finish. It was concluded that, despite the higher cement stresses with debonded stems, polished prostheses do not provoke the damage accumulation failure scenario. (C) 2003 IPEM. Published by Elsevier Ltd. All rights reserved.

Computer simulating a trial of a load-bearing implant: example of an intramedullary prosthesis

Computational modelling is becoming ever more important for obtaining regulatory approval for new medical devices. An accepted approach is to infer performance in a population from an analysis conducted for an idealised or ‘average’ patient; we present here a method for predicting the performance of an orthopaedic implant when released into a population—effectively simulating a clinical trial. Specifically we hypothesise that an analysis based on a method for predicting the performance in a population will lead to different conclusions than an analysis based on an idealised or ‘average’ patient. To test this hypothesis we use a finite element model of an intramedullary implant in a bone whose size and remodelling activity is different for each individual in the population. We compare the performance of a low Young’s modulus implant (View the MathML source) to one with a higher Young’s modulus (200 GPa). Cyclic loading is applied and failure is assumed when the migration of the implant relative to the bone exceeds a threshold magnitude. The analysis for an idealised of ‘average’ patient predicts that the lower modulus device survives longer whereas the analysis simulating a clinical trial predicts no statistically-significant tendency (p=0.77) for the low modulus device to perform better. It is concluded that population-based simulations of implant performance–simulating a clinical trial–present a very valuable opportunity for more realistic computational pre-clinical testing of medical devices.