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Cerebral phaeohyphomycosis is infection of the central nervous system (CNS) caused by dematiaceous fungi. The most common mechanisms of infection are by direct extension from the paranasal sinuses or by hematogenous spread. The mortality rate is high and ranges from 50%–79% in the limited studies on this infection. Our case describes a young man without any preexisting disease who acquired cerebral phaeohyphomycosis following nasal inhalation of garden mushrooms. Despite aggressive treatment, he ultimately died due to this severe infection. Our case report discusses our treatment approach and reviews the literature on this deadly infection. Keywords: fungal infection, cerebral abscess, Bipolaris, phaeohyphomycosis

The objective was to evaluate the performance of decellularised porcine superflexor tendon (pSFT) as an anterior cruciate ligament (ACL) reconstruction device. The ACL of adult sheep was reconstructed with decellularised pSFT or ovine allograft SFT and animals sacrificed at 4, 12 and 26 weeks (n = 4 per group) for biological evaluation and 26 weeks (n = 6) for biomechanical evaluation of the grafts. Both grafts showed good in vivo performance with no major differences at macroscopic evaluation post euthanasia. Histopathology revealed an inflammatory reaction to both grafts at 4 weeks, which reduced by 26 weeks. There was advanced cellular ingrowth from 12 weeks, ligamentisation of intra-articular grafts, ossification and formation of Sharpey's fibers at the graft/bone junctions. Immunohistochemistry showed that at 4 and 12 weeks, the host response was dominated by CD163+ M2 macrophages and a cell infiltrate comprising α-SMA + myofibroblasts , CD34 + and CD271+ progenitor cells . At 26 weeks the biomechanical properties of decellularised pSFT and oSFT grafts were comparable, with all grafts failing in the intra-articular region. This study provides new insight into constructive remodelling of tendons used for ACL replacement and evidence of integration and functional performance of a decellularised xenogeneic tendon with potential as an alternative for ACL reconstruction.

After hip replacement, in cases where there is instability at the joint, contact between the femoral head and the acetabular liner can move from the bearing surface to the liner rim, generating edge loading conditions. This has been linked to polyethylene liner fracture and led to the development of a regulatory testing standard (ISO 14242:4) to replicate these conditions. Performing computational modelling alongside simulator testing can provide insight into the complex damage mechanisms present in hard-on-soft bearings under edge loading. The aim of this work was to evaluate the need for inertia and elastoplastic material properties to predict kinematics (likelihood of edge loading) and plastic strain accumulation (as a damage indicator). While a static, rigid model was sufficient to predict kinematics for experimental test planning, the inclusion of inertia, alongside elastoplastic material, was required for prediction of plastic strain behaviour. The delay in device realignment during heel strike, caused by inertia, substantially increased the force experienced during rim loading (e.g. 600 N static rigid, ∼1800 N dynamic elastoplastic, in one case). The accumulation of plastic strain is influenced by factors including cup orientation, swing phase force balance, the moving mass, and the design of the device itself. Evaluation of future liner designs could employ dynamic elastoplastic models to investigate the effect of design feature changes on bearing resilience under edge loading.

A range of surgical techniques and osteochondral interventions have been developed for early stage chondral/osteochondral repair interventions in the knee however, methods for functional, pre-clinical assessment of these therapies are limited. In this study, a method for simulating physiological loading and motion in the porcine patellofemoral joint was developed using a 6-axis simulator. As an example of how the method can be used, the influence of surgical positioning of osteochondral allografts in the patella on cartilage wear, deformation and damage and graft stability was investigated in this porcine patellofemoral joint model. The functional performance of allografts implanted either optimally (flush with the cartilage surface) or 1 mm proud of the cartilage surface was compared to a positive control (stainless steel pin implanted 1 mm proud of the cartilage surface), a negative control (no intervention) and a defect model. Allografts implanted flush with the surrounding cartilage could restore the articulating surface of the patella resulting in low wear, damage and deformation of the opposing cartilage surface, similar to that of the negative control group. Implanting the graft proud of the patella surface resulted in cartilage lesions on the femoral trochlea (ICRS grade 2) and a cartilage volume difference of 2.0 ± 3.9 mm3; the positive controls resulted in more severe lesions, a higher volume difference (14.2 ± 7.4 mm3) which in some cases exposed subchondral bone (ICRS grade 4). Defects in the patella caused deformation of the opposing cartilage surface. All grafts implanted in the patella subsided over the duration of the study. This study demonstrated a method that can be used to evaluate osteochondral repair strategies in the patellofemoral joint applying physiological loading and motions.

Osteochondral grafts are used clinically to repair cartilage and bone defects and to restore the congruent articulating surfaces of the knee joint following cartilage damage or injury. The clinical success of such osteochondral grafts is heavily reliant on the biomechanical and tribological properties of the surgical repair; however, a limited number of studies have investigated these factors. The aim of this study was to evaluate the influence of graft harvesting and implantation technique as well as bone properties on the primary stability of press-fit implanted osteochondral grafts using a series of uniaxial experimental push-in and push-out tests. Animal (porcine and bovine) knees were used to deliver models of different bone properties (elastic modulus and yield stress). The study showed the graft harvesting method using either a chisel or drill-aided trephine to have no influence on primary graft stability; however, the preparation technique for the graft recipient site was shown to influence the force required to push the graft into the host tissue. For example, when the length of the graft was equal to the recipient site (bottomed), the graft was more stable and dilation of the recipient site was shown to reduce short-term graft stability especially in immature or less dense bone tissue. The push-out tests which compared tissue of different skeletal maturities demonstrated that the maturity of both the graft and host bone tissue to influence the stability of the graft. A higher force was required to push out more skeletally mature grafts from mature bone tissue. The study demonstrates the importance of surgical technique and bone quality/properties on the primary stability and ultimately, the success of osteochondral grafts in the knee.

Hip simulation is a common technique for pre-clinical evaluation of wear performance of total hip arthroplasty. Standard techniques replicate kinematics of walking patterns of a typical patient. Attention has focussed in developing simulations of other typical patient daily activities to improve accuracy of wear predictions. A method for simulating stop-dwell-start motion during patient walking and the effect on 36-mm metal-on-metal total hip arthroplasty was previously presented by the authors. This study sought to extend the previous work to look at the effect of these conditions on ceramic-on-ceramic, metal-on-polyethylene and ceramic-on-polyethylene bearings. Two stop-dwell-start protocols were used: one reproducing average patient movement patterns and one examining more severe conditions. For all materials tested, no significant increase in wear was observed under average stop-dwell-start conditions, suggesting the bearing types tested are robust to this type of activity. A significant increase in wear was observed for metal-on-metal, metal-on-polyethylene and ceramic-on-polyethylene bearings under severe stop-dwell-start conditions, this was attributed to depletion of lubricant in the bearing during the dwell period. A greater relative increase in wear was observed for metal-on-metal bearings compared with metal-on-polyethylene and ceramic-on-polyethylene bearings. This may be explained by the contributions of the different lubrication mechanisms in each bearing type. Wear of ceramic-on-ceramic was very low in all tests, suggesting normal measurement variation was masking any effect of the adverse conditions. It was not possible to determine any effect of the different activities. These results emphasise the importance of exploring adverse patient activity simulations. The increase in wear rate associated with an adverse activity such as seen in stop-dwell-start motion, has to be considered in the context of the frequency of the adverse activity cycle relative to other activities such as standard continuous walking, to determine the impact on the total wear in a given time period.

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A smartphone application (app) may facilitate identification of cardiac implanted electrical devices (CIEDs) (e.g., pacemakers and defibrillators) in urgent or emergent settings. Programming and interrogation of CIEDs requires the use of proprietary software and manufacturer-specific equipment. In

Anterior cruciate ligament rupture is rising in its prevalence amongst the young and those with physically active lifestyles. Acellular human patellar tendon (PT) grafts offer a promising restoration solution, returning knee joint stability and overcoming some of the current disadvantages of autologous or allogeneic grafts. However, it is necessary to ensure that the decellularisation bio-processes involved do not cause structural changes in the microstructure of the tendon tissue that may adversely affect the mechanical properties, particularly with respect to the physiological range of loading.Sixteen cadaveric human PT grafts were sourced and processed from eight donors, with full ethical approval and consent for use in research. Eight specimens were allocated for decellularisation, while the remaining eight contralateral specimens were used as native controls. Testing consisted of 12 preconditioning cycles followed by uniaxial extension until failure occurred. Stress–strain data was then fitted to a bi-linear model using least squares regression by a custom-written Matlab script. The elastic moduli for the toe region and linear region of each specimen were determined, in addition to the transition point co-ordinates and strain energy density for increasing strain. No significant differences were found between groups for all of the parameters investigated. Hence, the shape and magnitude of the stress–strain profile was found to be the same for both groups throughout loading.The results of this study indicated that decellularisation appeared to have no effect on the material properties of human PT grafts under quasistatic conditions. Therefore, acellular human PT grafts can offer a viable additional solution for ACL replacement compared to current autologous and allogeneic treatment options.

The occurrence of edge loading in hip joint replacement has been associated with many factors such as prosthetic design, component malposition and activities of daily living. The present study aimed to quantify the occurrence of edge loading/contact at the articulating surface and to evaluate the effect of cup angles and edge loading on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR) during different daily activities. A three-dimensional finite element model was developed based on a modular MoP bearing system. Different cup inclination and anteversion angles were modelled and six daily activities were considered. The results showed that edge loading was predicted during normal walking, ascending and descending stairs activities under steep cup inclination conditions (≥55°) while no edge loading was observed during standing up, sitting down and knee bending activities. The duration of edge loading increased with increased cup inclination angles and was affected by the cup anteversion angles. Edge loading caused elevated contact pressure at the articulating surface and substantially increased equivalent plastic strain of the polyethylene liner. The present study suggested that correct positioning the component to avoid edge loading that may occur during daily activities is important for MoP THR in clinical practice.

The aim of this paper is to present the implementation of Fractional-Order Proportional-Integral-Derivative (FOPID) to control the step response of the first-order circuit. With FOPID control, we obtain a satisfying result. The FOPID controller outperforms the classical integer PID, wherein both of them are optimized with the Nelder-Mead method. The FOPID controller succeeds to regulate the output of the system to our desired set point with better settling time and rise time than the classical one. In addition, hardware realization is presented with Arduino Uno.

A review of research undertaken to evaluate the biomechanical stability and biotribological behaviour of osteochondral grafts in the knee joint and a brief discussion of areas requiring further improvement in future studies are presented. The review takes into consideration osteochondral autografts, allografts, tissue engineered constructs and synthetic and biological scaffolds.

ObjectiveOn April 15, 2013, two improvised explosive devices (IEDs) exploded at the Boston Marathon and 264 patients were treated at 26 hospitals in the aftermath. Despite the extent of injuries sustained by victims, there was no subsequent mortality for those treated in hospitals. Leadership decisions and actions in major trauma centers were a critical factor in this response.MethodsThe objective of this investigation was to describe and characterize organizational dynamics and leadership themes immediately after the bombings by utilizing a novel structured sequential qualitative approach consisting of a focus group followed by subsequent detailed interviews and combined expert analysis.ResultsAcross physician leaders representing 7 hospitals, several leadership and management themes emerged from our analysis: communications and volunteer surges, flexibility, the challenge of technology, and command versus collaboration.ConclusionsDisasters provide a distinctive context in which to study the robustness and resilience of response systems. Therefore, in the aftermath of a large-scale crisis, every effort should be invested in forming a coalition and collecting critical lessons so they can be shared and incorporated into best practices and preparations. Novel communication strategies, flexible leadership structures, and improved information systems will be necessary to reduce morbidity and mortality during future events. (Disaster Med Public Health Preparedness. 2015;9:489–495)

Parameterised finite element models of the human hip have the potential to allow controlled analysis of the effect of individual geometric features on the contact mechanics of the joint. However, the challenge lies in defining a set of parameters which sufficiently capture the joint geometry in order to distinguish between individuals. In this study, a simple set of parameters to describe the geometries of acetabulum and cartilage in the hip were extracted from two segmentation-based models, which were then used to generate the parameterised finite element models for the two subjects. The contact pressure and contact area at the articular surface predicted from the parameterised finite element models were compared with the results from the segmentation-based models. The differences in the predicted results between the parameterised models and segmentation-based models were found to be within 11% across seven activities simulated. In addition, the parameterised models were able to replicate features of the contact pressure/area fluctuations over the loading cycle that differed between the two subjects. These results provide confidence that the parameterised approach could be used to generate representative finite element models of the human hip for contact analysis. Such a method has the potential to be used to systematically evaluate geometric features that can be captured from simple clinical measurements and provide a cost- and time-effective approach for stratification of the acetabular geometries in the patient population.

Background Preclinical durability testing of hip replacement implants is standardised by ISO-14242-1 (2002) which is based on historical inverse dynamics analysis using data obtained from a small sample of normal healthy individuals. It has not been established whether loading cycles derived from normal healthy individuals are representative of loading cycles occurring in patients following total hip replacement. Methods Hip joint kinematics and hip contact forces derived from multibody modelling of forces during normal walking were obtained for 15 asymptomatic total hip replacement patients and compared to 38 normal healthy individuals and to the ISO standard for pre-clinical testing. Findings Hip kinematics in the total hip replacement patients were comparable to the ISO data and the hip contact force in the normal healthy group was also comparable to the ISO cycles. Hip contact forces derived from the asymptomatic total hip replacement patients were comparable for the first part of the stance period but exhibited 30% lower peak loads at toe-off. Interpretation Although the ISO standard provides a representative kinematic cycle, the findings call into question whether the hip joint contact forces in the ISO standard are representative of those occurring in the joint following total hip replacement.

Finite element models are becoming increasingly useful tools to conduct parametric analysis, design optimisation and pre-clinical testing for hip joint replacements. However, the verification of the finite element model is critically important. The purposes of this study were to develop a three-dimensional anatomic finite element model for a modular metal-on-polyethylene total hip replacement for predicting its contact mechanics and to conduct experimental validation for a simple finite element model which was simplified from the anatomic finite element model. An anatomic modular metal-on-polyethylene total hip replacement model (anatomic model) was first developed and then simplified with reasonable accuracy to a simple modular total hip replacement model (simplified model) for validation. The contact areas on the articulating surface of three polyethylene liners of modular metal-on-polyethylene total hip replacement bearings with different clearances were measured experimentally in the Leeds ProSim hip joint simulator under a series of loading conditions and different cup inclination angles. The contact areas predicted from the simplified model were then compared with that measured experimentally under the same conditions. The results showed that the simplification made for the anatomic model did not change the predictions of contact mechanics of the modular metal-on-polyethylene total hip replacement substantially (less than 12% for contact stresses and contact areas). Good agreements of contact areas between the finite element predictions from the simplified model and experimental measurements were obtained, with maximum difference of 14% across all conditions considered. This indicated that the simplification and assumptions made in the anatomic model were reasonable and the finite element predictions from the simplified model were valid.

Hip joint simulators have been largely used to assess the wear performance of joint implants. Due to the complexity of joint movement, the motion mechanism adopted in simulators varies. The motion condition is particularly important for ultra-high molecular weight polyethylene (UHMWPE) since polyethylene wear can be substantially increased by the bearing cross-shear motion. Computational wear modelling has been improved recently for the conventional UHMWPE used in total hip joint replacements. A new polyethylene wear law is an explicit function of the contact area of the bearing and the sliding distance, and the effect of multidirectional motion on wear has been quantified by a factor, cross-shear ratio. In this study, the full simulated walking cycle condition based on a walking measurement and two simplified motions, including the ISO standard motion and a simplified ProSim hip simulator motion, were considered as the inputs for wear modelling based on the improved wear model. Both the full simulation and simplified motions generated the comparable multidirectional motion required to reproduce the physiological wear of the bearing in vivo. The predicted volumetric wear of the ProSim simulator motion and the ISO motion conditions for the walking cycle were 13% and 4% lower, respectively, than that of the measured walking condition. The maximum linear wear depths were almost the same, and the areas of the wear depth distribution were 13% and 7% lower for the ProSim simulator and the ISO condition, respectively, compared with that of the measured walking cycle motion condition., Highlights ► Computational wear modelling was conducted for UHMWPE hip joints. ► The loading/motion of the measured walking, the ISO and the ProSim simulator was analysed. ► The cross-shear ratios, slide tracks, and contact pressures were compared. ► The comparable wear was predicted.

The clinical incidence of squeaking has been reported with increasing frequency, with ceramic-on-ceramic bearings seemingly most affected. This study investigated potential causes of squeaking in hard-on-hard hip bearings through 2 sets of experimental conditions. Bearing clearance appeared to affect the incidence of squeaking in metal-on-metal surface arthroplasties. The addition of third-body particles to the interface for total hip arthroplasties also affected the incidence of squeaking. In both studies, the incidence of squeaking correlated well with elevated friction. The findings of this study suggest that a likely cause of squeaking in the hip arthroplasty is adverse tribological conditions caused by suboptimal lubrication. There are numerous factors that may cause the suboptimal lubrication, and therefore, it is unlikely that an individual cause for squeaking will be identified.

Unicondylar knee arthroplasty (UKA) has become a popular alternative to total knee arthroplasty or high tibial osteotomy for unicompartmental knee conditions. This study investigated the effects of kinematics and femoral liftoff on the wear of fixed and mobile versions of a UKA design. The fixed bearing had lower wear than the mobile bearing under all conditions. Wear was higher in lateral bearings than medial bearings, indicating that the increased sliding distance laterally had a greater effect than the greater loading medially. Femoral condylar liftoff resulted in increased wear in the medial UKAs but reduced wear in the lateral UKAs for both the bearing designs. The reduced wear rates observed for the fixed UKA bearings highlight the potential for a longer osteolysis-free clinical outcome for these devices.

A new Stratified Approach For Enhanced Reliability (SAFER) pre-clinical simulation testing of joint prostheses has been described in a preceding paper in this volume. The application of SAFER in vitro simulation and testing to metal-on-metal bearings is described in this review paper. The review aims to provide further understanding of the reasons for, and causes of, increased wear in metal-on-metal hips in a proportion of patients. Variation in positioning (mal-positioning) of the head and cup in hip prostheses results in the head contacting the rim of the cup and producing increased wear. Variation in both translational and rotational positioning has been investigated. Variation in translational positioning of the centres of the head and cup, which is not detected on radiographs, is a frequent occurrence clinically and can result in a substantial increase in wear rate. The variation in translational positioning acts synergistically with variation in rotational positioning to produce substantial increases in wear. These recent findings are consistent with the wear mechanisms and formation of stripe wear reported for ceramic-on-ceramic bearings over a decade ago, and provide insight into the reasons for the variation and increases in the wear rate found clinically in metal-on-metal hips in specific patients, which may cause premature failure.

Study Design An in-vitro study of the wear rates of the Charite lumbar total disc replacement.

Surgeons have used cryopreserved vascular allografts successfully for many years to treat arterial occlusive disease and to repair arterial aneurysms. Vascular allografts demonstrate high patency rates but contain viable cells, which may evoke a rejection response following implantation. Removing the cells could prevent such a response and negate the need for cryopreservation and ultra-low temperature storage. The objectives of the study were to characterize human common femoral arteries and develop a decellularization protocol with a view to the generation of biocompatible and biomechanically functional vascular grafts for use in vascular bypass and arteriovenous access. The arteries were decellularized by subjecting the tissue to a single freeze-thaw cycle followed by sequential incubation in hypotonic tris buffer and low concentration sodium dodecyl sulphate. Each artery was disinfected using 0.1% (v/v) peracetic acid. Histological analysis demonstrated a lack of cells following decellularization and confirmed the integrity of the tissue histioarchitecture and retention of major structural proteins. There was a95% reduction in DNA levels. The acellular tissues and extracts were not cytotoxic to either mouse 3T3 or baby hamster kidney cells. Biomechanical properties were determined by burst pressure, compliance, and tensile tests, which confirmed the retention of biomechanical properties following decellularization. In conclusion the study has developed a suitable protocol for the removal of cells from human common femoral arteries without adversely affecting the biochemical or biomechanical properties. These properties indicate the potential use for acellular human common femoral arteries for vascular bypass or arteriovenous access.

In vitro studies were conducted to investigate the incidence of squeaking in total hip replacements, examining ceramic-on-ceramic, ceramic-on-metal, and metal-on-metal bearings. Third-body debris materials were introduced into each bearing, and the incidence of squeaking was noted through simple friction studies. The addition of ceramic fragments caused squeaking in all bearings, although most significantly in the metal-on-metal bearings. The incidence of squeaking correlated well with elevated friction. It is proposed that squeaking in total hip replacement is related to adverse tribological conditions, where the lubrication of the implant is compromised.

Effective and capable people are in high demand amongst businesses and educational establishments. Companies are not getting the best out of their people. It appears that there is a gap between what people are saying they are going to do and what they actually do. This research, based on a combination of what is already known about the subject matter under investigation and the practical experiences of research participants, investigated how this organizational behavior gap could be closed and what the potential benefits would be for both individuals and companies. The main focus of this research was to identify effective solutions how talkers could become doers and how talkers would benefit from adopting and applying the suggested recommendations how changes in attitude/behaviors and routines could lead to improved action-based capabilities. The outcome of this research suggests that the contributions made by this research can be measured through appropriate Key Performance Indicators (KPIs) to measure and demonstrate the effectiveness of considered performance improvements. It is suggested that the contributions from this research can be applied universally provided that cultural diversity is taken into consideration.

We recently developed a one-dimensional imager of neutrons on the Z facility. The instrument is designed for Magnetized Liner Inertial Fusion (MagLIF) experiments, which produce D-D neutrons yields of ∼3 × 1012. X-ray imaging indicates that the MagLIF stagnation region is a 10-mm long, ∼100-μm diameter column. The small radial extents and present yields precluded useful radial resolution, so a one-dimensional imager was developed. The imaging component is a 100-mm thick tungsten slit; a rolled-edge slit limits variations in the acceptance angle along the source. CR39 was chosen as a detector due to its negligible sensitivity to the bright x-ray environment in Z. A layer of high density poly-ethylene is used to enhance the sensitivity of CR39. We present data from fielding the instrument on Z, demonstrating reliable imaging and track densities consistent with diagnosed yields. For yields ∼3 × 1012, we obtain resolutions of ∼500 μm.

Patellofemoral complications are cited as a leading cause for revision surgery following total knee arthroplasty. Despite widespread clinical use, the decision to resurface the patella, or not, is controversial and remains surgeon dependent. Damage to the patellar component can lead to revision surgery; however, little work exists investigating the damage they sustain in vivo. Twenty-four retrieved patellar components were assessed for damage. There was a wide variation in wear scar morphology, although the mean wear scar area spanned mediolaterally in a band across the articular surface and was 364.32±64.7 mm2 in area. Maximum linear penetration was located in the lateral region of the articular surface. Assessment of damage mode grading indicated that it was more severe in the lateral quadrant, although the method's lack of consideration of the chronological progression of wear creates uncertainty over this finding. Volume change ranged from −1.3 to −45.16 mm3/year, and maximum penetration was in the lateral region. Damage to the patellar component of knee replacement has been shown to be significant. The number of components in the study was too small to determine a difference in damage in all-polyethylene and metal-backed designs; however, the volume loss of all-polyethylene patellae was found to be significant.

High wear rates and high patient ion levels have been associated with high (55 degrees) cup inclination angles for metal-on-metal surface replacements. Wear rates and patterns have been simulated for ceramic-on-ceramic bearings by applying microseparation to replicate head offset deficiency. We tested 39-mm metal-on-metal surface replacements (n = 5) in a hip simulator with (A) an increased cup inclination angle of 60 degrees and (B) an increased cup inclination angle and microseparation over 2 million cycles. (A) resulted in a ninefold increase in wear rate and (B) resulted in a 17-fold increase in wear rate compared to a standard gait condition study. Wear particles produced under microseparation conditions were larger than those produced under standard conditions but of similar shape (round to oval). The data suggest both head and cup position influence the wear of surface replacements; we believe it likely bearings with high wear either have a high cup inclination angle, an offset deficient head, or a combination of both.

Tendring Technology College has harnessed a robotic buggy and Web-based learning to transform D&T and ICTteaching.

Nanometre-sized particles of ultra-high molecular weight polyethylene have been identified in the lubricants retrieved from hip simulators. Tissue samples were taken from seven failed Charnley total hip replacements, digested using strong alkali and analysed using high-resolution field emission gun-scanning electron microscopy to determine whether nanometre-sized particles of polyethylene debris were generated in vivo. A randomised method of analysis was used to quantify and characterise all the polyethylene particles isolated. We isolated nanometre-sized particles from the retrieved tissue samples. The smallest identified was 30 nm and the majority were in the 0.1 μm to 0.99 μm size range. Particles in the 1.0 μm to 9.99 μm size range represented the highest proportion of the wear volume of the tissue samples, with 35% to 98% of the total wear volume comprised of particles of this size. The number of nanometre-sized particles isolated from the tissues accounted for only a small proportion of the total wear volume. Further work is required to assess the biological response to nanometre-sized polyethylene particles.

Tai Chi—Moving for Better Balance, a falls-prevention program developed from a randomized controlled trial for community-based use, was evaluated with the RE-AIM framework in 6 community centers. The program had a 100% adoption rate and 87% reach into the target older adult population. All centers implemented the intervention with good fidelity, and participants showed significant improvements in health-related outcome measures. This evidence-based tai chi program is practical to disseminate and can be effectively implemented and maintained in community settings.

The performance of novel ceramic-on-metal bearing couples has been compared with metal-on-metal and ceramic-on-ceramic bearing couples in laboratory and short-term clinical studies. Laboratory studies compared ceramic-on-metal with metal-on-metal and ceramic-on-ceramic bearings with diameters of 28 and 36 mm under standard conditions and under adverse conditions with head loading on the rim of the cup. Clinical studies compared metal ion levels in ceramic-on-metal with metal-on-metal, ceramic-on-ceramic, and ceramic-on-polyethylene bearings in a randomized prospective study. In the laboratory studies, friction, wear, and ion levels were lower in ceramic-on-metal bearings compared with metal-on-metal, with results similar to ceramic-on-ceramic couples. Under adverse conditions and rim loading, all bearings showed increased wear with lower wear and absence of stripe wear in ceramic-on-metal compared with metal-on-metal bearings. Short-term studies in 31 patients at 6 months revealed lower metal ion levels (cobalt and chromium) in those with ceramic-on-metal compared with metal-on-metal bearings.

Before 1914 several government departments dealt on a routine basis with Britons travelling worldwide. The contexts were extremely varied and ranged from royal travel to scientific discovery, to espionage and affected those undertaking private travel as well as those on official business. This study focuses particularly on the consular tour, on outrages committed against British travellers, and on the issue of travellers bearing arms, often for sporting purposes. By examining the administrative arrangements of the Foreign and India Offices for dealing with such issues it seeks to illuminate the way in which officials from these departments perceived the overseas. The shared assumptions that existed were, in part, inculcated in the leading public schools and universities and were reinforced in the gentlemen's clubs of London's West End and in various learned societies. This article explores a neglected aspect of the official mind at a time when assumptions of British pre-eminence were beginning to be challenged.

A Translational Research Symposium was organized at the 2014 annual meeting of the European society for biomaterials. This brought together leading Tier one companies in clinical biomaterials and medical device markets, small and medium enterprises and entrepreneurial academics who shared their experiences on taking biomaterials technologies to commercial endpoints, in the clinics. The symposium focused on "Progressing Innovation in Biomaterials. From the Bench to the Bed of Patients". The aim of the present document is to illustrate the content of the symposium and to highlight the key lessons from selected lectures.

Advancements in knee replacement design, material and sterilisation processes have provided improved clinical results. However, surface wear of the polyethylene leading to osteolysis is still considered the longer-term risk factor. Experimental wear simulation is an established method for evaluating the wear performance of total joint replacements. The aim of this study was to investigate the influence of simulation input conditions, specifically input kinematic magnitudes, waveforms and directions of motion and position of the femoral centre of rotation, on the wear performance of a fixed-bearing total knee replacement through a combined experimental and computational approach. Studies were completed using conventional and moderately cross-linked polyethylene to determine whether the influence of these simulation input conditions varied with material. The position of the femoral centre of rotation and the input kinematics were shown to have a significant influence on the wear rates. Similar trends were shown for both the conventional and moderately cross-linked polyethylene materials, although lower wear rates were found for the moderately cross-linked polyethylene due to the higher level of cross-linking. The most important factor influencing the wear was the position of the relative contact point at the femoral component and tibial insert interface. This was dependent on the combination of input displacement magnitudes, waveforms, direction of motion and femoral centre of rotation. This study provides further evidence that in order to study variables such as design and material in total knee replacement, it is important to carefully control knee simulation conditions. This can be more effectively achieved through the use of displacement control simulation.

Metal-on-polyethylene total disc replacements have been an alternative to spinal fusion in the lumbar spine under certain indications for more than a decade. Recently, cervical total disc replacement has also become an alternative to cervical fusion. Knowledge acquired from years of in vitro simulator studies on other joint replacements has highlighted the risks associated with premature wear due to unforeseen adverse clinical conditions and the effect of particulate debris on surrounding natural tissues. Having no evidence of the type and composition of the lubricating fluid that will result after spinal arthroplasty, a study on the effects of lubricant serum concentration was undertaken. The wear rate was shown to be inversely proportional to protein content of the serum over a range of 50%–3% bovine serum to water concentration.

The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

Total disc arthroplasty offers both theoretical and practical advantages over fusion surgery as a treatment for low back pain. In the majority of cases, these relatively new devices owe much of their evolution to the success of other total joint replacements, in particular, hip and knee prostheses, which have been developed over the last four decades. The demands on these new joints are substantial, and although short-term data appear to demonstrate good outcomes in a significant proportion of patients, medium- and longer-term results are sparse. The wear performance of these devices should be emphasized as a possible cause of failure through both adverse biological reactions, such as osteolysis, and inappropriate biomechanics, similar to that observed in a small proportion but numerically significant number of hip and knee prostheses. This article reviews the current technology in terms of the performance parameters these devices are required to operate within and the evidence for future problems akin to those observed in other joint arthroplasties. The article calls for more rigorous preclinical testing and follow-up protocols, based on the technologies and procedures developed for the current range of conventional hip and knee replacements.

Tribology of hip joints is reviewed, covering a full spectrum from natural hip joints to total hip replacements, as well as tissue engineered articular cartilage. The importance of integrated tribological studies of contact mechanics, friction, wear and lubrication, as well as fully coupled with biological considerations, has been emphasized. The exact lubrication mechanism in natural hip joints is still not clear, although the unique biphasic characteristics of articular cartilage play an important role. Tribological studies of bearing surfaces for artificial hip joint replacements are important in developing and optimizing alternative material combinations to conventional polyethylene. Recently developed tissue engineered articular cartilage has been shown to be inadequate as far as the tribological property is concerned.

OBJECTIVES: To determine the relative effects of cobblestone mat walking, in comparison with regular walking, on physical function and blood pressure in older adults. DESIGN: Randomized trial with allocation to cobblestone mat walking or conventional walking. SETTING: General community in Eugene, Oregon. PARTICIPANTS: One hundred eight physically inactive community-dwelling adults aged 60 to 92 (mean age � standard deviation 577.5 � 5.0) free of neurological and mobility-limiting orthopedic conditions. INTERVENTION: Participants were randomized to a cobblestone mat walking condition (n 554) or regular walking comparison condition (n 554) and participated in 60-minute group exercise sessions three times per week for 16 consecutive weeks. MEASUREMENTS: Primary endpoint measures were balance (functional reach, static standing), physical performance (chair stands, 50-foot walk, Up and Go), and blood pressure (systolic, diastolic). Secondary endpoint measures were Short Form-12 physical and mental health scores and perceptions of health-related benefits from exercise. RESULTS: At the 16-week posttest, differences between the two exercise groups were found for balance measures (P 5.01), chair stands (Po.001), 50-foot walk (P 5.01), and blood pressure (P 5.01) but not for the Up and Go test (P 5.14). Although significant within-group changes were observed in both groups for the secondary outcome measures, there were no differences between intervention groups. CONCLUSION: Cobblestone mat walking improved physical function and reduced blood pressure to a greater extent than conventional walking in older adults. Additional benefits of this walking program included improved health-related quality of life. This new physical activity may provide a therapeutic and health-enhancing exercise alternative for older adults. J Am Geriatr Soc 2005.

Summary In recent years there has been renewed interest in metal-on-metal (MOM) bearings for both total hip replacement and surface replacement hip arthroplasty. Short-term clinical results have been encouraging; with low wear rates and few prostheses requiring revision. This review concentrates on the factors that affect the wear of all metal devices such as specification of the alloy, processing techniques, head diameter, clearance between the components, lubrication regime, loading and surface finish. The concerns associated with MOM bearings are also discussed. These include wear particle release and dissemination, and elevated metal ion levels, which may lead to cytotoxicity, hypersensitivity and genotoxicity.

Objective: To examine the relation between built environment factors (representing several dimensions of urban form of neighbourhoods) and walking activity at both the neighbourhood level and the resident level, in an older adult sample. Design, setting, participants: A cross sectional, multilevel design with neighbourhoods as the primary sampling unit and senior residents as the secondary unit. Five hundred and seventy seven residents (mean age = 74 years, SD = 6.3 years) participated in the survey, which was conducted among 56 city defined neighbourhoods in Portland, Oregon, USA. Neighbourhood level variables were constructed using geographical information systems. Resident level variables consisted of a mix of self reports and geocoded data on the built environment. Main outcome measure: Self reported neighbourhood walking. Main results: A positive relation was found between built environment factors (density of places of employment, household density, green and open spaces for recreation, number of street intersections) and walking activity at the neighbourhood level. At the resident level, perceptions of safety for walking and number of nearby recreational facilities were positively related to high levels of walking activity. A significant interaction was observed between number of street intersections and perceptions of safety from traffic. Conclusions: Certain neighbourhood built environment characteristics related to urban form were positively associated with walking activity in the neighbourhoods of senior residents. Public health promotion of walking activity/urban mobility and the design of interventions need to consider the contribution of neighbourhood level built environment influences.

Metal-on-metal is one potential bearing option for total hip arthroplasty (THA). Proponents of the bearing have suggested that if the tribology is optimal, volumetric wear may occur at levels at least one order of magnitude lower than metal-on-polyethylene bearings. We present a unique postmortem case of a well fixed, metal-on-metal, McKee-Farrar total hip arthroplasty implanted 30 years previously that was clinically asymptomatic in life. Clinical and radiological examination is supplemented by tribological examination of the bearing and histopathological examination of the cement-bone interface.

LI, F., P. HARMER, K. J. FISHER, and E. MCAULEY. Tai Chi: Improving Functional Balance and Predicting Subsequent Falls in Older Persons. Med. Sci. Sports Exerc., Vol. 36, No. 12, pp. 2046–2052, 2004. Purpose: To determine whether improved functional balance through a Tai Chi intervention is related to subsequent reductions in falls among elderly persons. Methods: Two hundred fifty-six healthy, physically inactive older adults aged 70–92 (mean age SD 77.48 4.95), recruited from a local health system in Portland, OR, participated in a 6-month randomized controlled trial, with allocation to Tai Chi or exercise stretching control, followed by a 6-month postintervention follow-up. Functional balance measures included Berg balance scale, dynamic gait index, and functional reach, assessed during the 6-month intervention period (baseline, 3-month, and 6-month intervention endpoint) and again at the 6-month postintervention follow-up. Fall counts were recorded during the 6-month postintervention follow-up period. Data were analyzed through intention-to-treat analysis of variance and logistic regression procedures. Results: Tai Chi participants who showed improvements in measures of functional balance at the intervention endpoint significantly reduced their risk of falls during the 6-month postintervention period, compared with those in the control condition (odds ratio (OR), 0.27, 95% confidence interval (CI), 0.07–0.96 for Berg balance scale; OR, 0.27, 95% CI, 0.09–0.87 for dynamic gait index; OR, 0.20, 95% CI, 0.05–0.82 for functional reach). Conclusions: Improved functional balance through Tai Chi training is associated with subsequent reductions in fall frequency in older persons. Key Words: BALANCE, FALL PREVENTION, AGING

Objectives: To determine the effectiveness of tai chi on self-rated sleep quality and daytime sleepiness in older adults reporting moderate sleep complaints. Design: Randomized, controlled trial with allocation to tai chi or exercise control. Setting: General community. Participants: One hundred eighteen women and men aged 60 to 92. Intervention: Participants were randomized into tai chi or low-impact exercise and participated in a 60-minute session, three times per week, for 24 consecutive weeks. Measurements: Primary outcome measures were the seven subscales of the Pittsburgh Sleep Quality Index (PSQI), PSQI global score, and Epworth Sleepiness Scale (ESS). Secondary outcome measures were physical performance (single leg stand, timed chair rise, 50-foot speed walk) and 12-item short form (SF-12) physical and mental summary scores. Results: Tai chi participants reported significant improvements in five of the PSQI subscale scores (sleep quality, sleep-onset latency, sleep duration, sleep efficiency, sleep disturbances) (P

Metal-on-metal bearings offer one possible solution to problems of osteo-lysis associated with ultra high molecular weight polyethylene (UHMWPE) wear debris generated during articulation in total joint replacements. Designs using larger bearing diameters are also possible with associated improvements in both range of motion and stability. There has been considerable debate as to the optimum metallurgical structure of the cobalt chrome alloys used in these metal-on-metal bearings. This review addresses the main metallurgical design issues in metal-on-metal bearing design and reviews some recent studies from two independent academic centres. Cobalt chrome alloys with a low carbon content, when paired against themselves, have been shown to have poor wear properties under both simple configuration and simulator testing. Other cobalt chrome alloy couples with higher carbon content, whether wrought, cast or cast and heat-treated, appear to have similar performance in clinically relevant wear simulation studies. (Hip International 2004; 14: 1-10).