Metal ion levels post primary unilateral Exeter total hip arthroplasty

BACKGROUND: Metal ion release is common following total hip arthroplasty, yet postoperative levels have not been defined for most stems currently used in clinical practice. AIM: To assess metal ion release in the serum of patients with well functioning unilateral Exeter V40 primary total hip arthroplasties one year after surgery. METHODS: Whole blood chromium and serum cobalt levels were measured in 20 patients following primary total hip arthroplasty with the Exeter V40 stem and a variety of acetabular components one year after surgery. RESULTS: Whole blood chromium levels were within the normal range (10-100 nmol/L), with a single mild elevation of serum cobalt (normal < 20 nmol/L). CONCLUSION: In well functioning primary unilateral total hip arthroplasty using the Exeter V40 stem with a variety of acetabular components one year post surgery, whole blood chromium levels are normal and serum cobalt elevations are rare and mild.

Managing Research Data: Mechanical testing and modelling of bone-implant constructs

Presentation by Dr Caroline Grant, Science & Engineering Faculty, IHBI, at Managing your research data seminar, 2012

Overview of building information modelling in healthcare projects

In this paper, we explore how BIM functionalities together with novel management concepts and methods have been utilized in thirteen hospital projects in the United States and the United Kingdom. Secondary data collection and analysis were used as the method. Initial findings indicate that the utilization of BIM enables a holistic view of project delivery and helps to integrate project parties into a collaborative process. The initiative to implement BIM must come from the top down to enable early involvement of all key stakeholders. It seems that it is rather resistance from people to adapt to the new way of working and thinking than immaturity of technology that hinders the utilization of BIM.

Lean construction, building information modelling and sustainability

This paper investigates the mutual relations of three current drivers of construction: lean construction, building information modelling and sustainability. These drivers are based on infrequently occurring changes, only incidentally simultaneous, in their respective domains. It is contended that the drivers are mutually supportive and thus synergistic. They are aligned in the sense that all require, promote or enable collaboration. It is argued that these three drivers should be implemented in a unified manner for rapid and robust improvements in construction industry performance and the quality of the constructed facilities and their benefits for stakeholders and wider society.

Analysis framework for the interaction between lean construction and building information modelling

Building with Building Information Modelling (BIM) changes design and production processes. But can BIM be used to support process changes designed according to lean production and lean construction principles? To begin to answer this question we provide a conceptual analysis of the interaction of lean construction and BIM for improving construction. This was investigated by compiling a detailed listing of lean construction principles and BIM functionalities which are relevant from this perspective. These were drawn from a detailed literature survey. A research framework for analysis of the interaction between lean and BIM was then compiled. The goal of the framework is to both guide and stimulate research; as such, the approach adopted up to this point is constructive. Ongoing research has identified 55 such interactions, the majority of which show positive synergy between the two.

Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

Based on the characterization by Atomic Force Microscopy (AFM), we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young’s moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton (CSK) and the intracellular fluid when the fixed chondrocytes is mainly governed by their intracellular fluid which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic (PHE) constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

The role of ethylene and cold temperature in the regulation of the apple POLYGALACTURONASE1 gene and fruit softening

Fruit softening in apple (Malus 3 domestica) is associated with an increase in the ripening hormone ethylene. Here, we show that in cv Royal Gala apples that have the ethylene biosynthetic gene ACC OXIDASE1 suppressed, a cold treatment preconditions the apples to soften independently of added ethylene. When a cold treatment is followed by an ethylene treatment, a more rapid softening occurs than in apples that have not had a cold treatment. Apple fruit softening has been associated with the increase in the expression of cell wall hydrolase genes. One such gene, POLYGALACTURONASE1 (PG1), increases in expression both with ethylene and following a cold treatment. Transcriptional regulation of PG1 through the ethylene pathway is likely to be through an ETHYLENE-INSENSITIVE3-like transcription factor, which increases in expression during apple fruit development and transactivates the PG1 promoter in transient assays in the presence of ethylene. A coldrelated gene that resembles a COLD BINDING FACTOR (CBF) class of gene also transactivates the PG1 promoter. The transactivation by the CBF-like gene is greatly enhanced by the addition of exogenous ethylene. These observations give a possible molecular mechanism for the coldand ethylene-regulated control of fruit softening and suggest that either these two pathways act independently and synergistically with each other or cold enhances the ethylene response such that background levels of ethylene in the ethylene-suppressed apples is sufficient to induce fruit softening in apples.

Epigenetic inactivation of chalcone synthase-A transgene transcription in petunia leads to a reversion of the post-transcriptional gene silencing phenotype

Petunia plants that exhibit a white-flowering phenotype as a consequence of chalcone synthase transgene-induced silencing occasionally give rise to revertant branches that produce flowers with wild-type pigmentation. Transcription run-on assays confirmed that the production of white flowers is caused by post-transcriptional gene silencing (PTGS), and indicated that transgene transcription is repressed in the revertant plants, providing evidence that induction of PTGS depends on the transcription rate. Transcriptional repression of the transgene was associated with cytosine methylation at CpG, CpNpG and CpNpN sites, and the expression was restored by treatment with either 5-azacytidine or trichostatin A. These results demonstrate that epigenetic changes occurred in the PTGS line, and these changes interfere with the initiation of transgene transcription, leading to a reversion of the PTGS phenotype.

Effect of constraint on void growth near a blunt crack tip

The growth of a single cylindrical hole ahead of a blunt crack tip was studied using large deformation finite element analysis in three-point bend specimens with different precrack depth. The effect of small second phase particles was taken into account by incorporating Gurson’s constitutive equation. The effects of strain hardening and the initial distance from the hole to the crack tip were also investigated. The results show that the variation of crack tip opening displacement with load is not sensitive to constraint level. The effects of constraint on the growth of hole and ductile initiation toughness are diminished with decreasing initial distance from the hole to the blunt crack tip.

Formation of neutral molecules of potential stellar interest by neutralisation of negative ions in a mass spectrometer - The application of experiment and molecular modelling in concert

This paper is a modified version of a lecture which describes the synthesis, structure and reactivity of some neutral molecules of stellar significance. The neutrals are formed in the collision cell of a mass spectrometer following vertical Franck-Condon one electron oxidation of anions of known bond connectivity. Neutrals are characterised by conversion to positive ions and by extensive theoretical studies at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31G(d) level of theory. Four systems are considered in detail, viz (i) the formation of linear C-4 and its conversion to the rhombus C-4, (ii) linear C-5 and the atom scrambling of this system when energised, (iii) the stable cumulene oxide CCCCCO, and (iv) the elusive species O2C-CO. This paper is not intended to be a review of interstellar chemistry: examples are selected from our own work in this area. (C) 2002 Elsevier Science Inc. All rights reserved.

Numerical investigation on stable crack growth in plane stress

Large deformation finite element analysis has been carried out to investigate the stress-strain fields ahead of a growing crack for compact tension .a=W D 0:5/ and three-point bend .a=W D 0:1 and 0:5/ specimens under plane stress condition. The crack growth is controlled by the experimental J -integral resistance curves measured by Sun et al. The results indicate that the distributions of opening stress, equivalent stress and equivalent strain ahead of a growing crack are not sensitive to specimen geometry. For both stationary and growing cracks, similar distributions of opening stress and triaxiality can be found along the ligament. During stable crack growth, the crack-tip opening displacement (CTOD) resistance curve and the cohesive fracture energy in the fracture process zone are independent of specimen geometry and may be suitable criteria for characterizing stable crack growth in plane stress.

Mechanics of microfilaments networks : a cross-scales study

The mechanical properties of microfilament networks are systematically summarized at different special scales in this paper. We have presented the mechanical models of single microfilaments and microfilament networks at microscale. By adopting a coarse-grained simulation strategy, the mechanical stability of microfilaments related cellular structures are analysed. Structural analysis is conducted to microfilament networks to understand the stress relaxation under compression. The nanoscale molecular mechanisms of the microfilaments deformation is also summarized from the viewpoint of molecular dynamics simulation. This paper provides the fundaments of multiscale modelling framework for the mechanical behaviours simulation of hierarchical microfilament networks.

Impact of the piston secondary motion on its slap force

A theoretical model is developed for the analysis of piston secondary motion. Based on this model, the slap force of a specific L6 diesel engine was compared when considering different boundary conditions, such as lubricating oil on cylinder liner, surface roughness, deformation of cylinder liner and piston skirt. It is concluded that it is necessary to consider the secondary motion of piston in the analysis of the inner excitation for an internal combustion engine. A more comprehensive consideration of the boundary condition (i.e., more close to the actual condition) will lead to a smaller maximum slap force, and among all boundary conditions considered in this paper, the structural deformation of the piston skirt and cylinder liner is the most influential factor. The theoretical model developed and findings obtained in this study will benefit the future analysis and design of advanced internal combustion engine structures.

School physical education in the post-report era : an analysis from public health

The 1996 United States Surgeon General’s report on physical activity and health represents a watershed moment in the modern history of physical activity and public health. Based on a compelling body of scientific evidence from the fields of medicine, epidemiology, physiology, and health psychology, the Surgeon General’s report proclaimed that people of all ages could improve their health and quality of life through lifelong practice of moderate physical activity (United States Department of Health and Human Services [USDHHS], 1996). Physical Activity and Health: A Report of the Surgeon General was an especially important publication for school physical education. Not only did the report acknowledge the importance of regular physical activity during childhood and adolescence, it also identified school physical education as an important vehicle for promoting healthenhancing physical activity in young people. “With evidence that success in this arena is possible, every effort should be made to encourage schools to require daily physical education in each grade and to promote physical activities that can be enjoyed throughout life” (USDHHS, 1996, p. 6). The purpose of this article is to discuss the status of school physical education since the release of the Surgeon General’s report on physical activity and health nearly a decade ago. Specifically, the article will address four questions: 1) What has been the historical role of physical education in physical activity and public health? 2) What impact, if any, has the Surgeon General’s report has had on physical education programs? 3) What impact should physical education have on public health and physical activity? 4) What should teacher education programs in physical education do to prepare physical education teachers, given the current role of physical education?