bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying a case-based reasoning method for fault diagnosis during maintenance
Authors: Tsai Y-T
Published: June 2009

The development of a fault-diagnosis system (FDS) could be helpful in identifying the source of faults before the occurrence of complete system failure. Here we report on such a diagnostic procedure for narrowing down maintenance tasks and shortening system downtime. A web-based FDS is developed based on case-based reasoning (CBR) from previous maintenance experience, for an injection moulding machine (IMM). The techniques of fault tree analysis (FTA) and information flow analysis are introduced to systematically clarify possible faults and symptoms shown by a system. A logical process is introduced to determine the correlation between the possible faults and the symptoms for computing case similarity while progressing CBR diagnosing. Some frontpages are developed for the CBR diagnosis using an ASP program in cooperation with a Microsoft Access database. The resultant FDS achieves good results with the potential for supporting remote IMM maintenance.
An investigation of sleeper voids using a flexible track model integrated with railway multi-body dynamics
Authors: Bezin Y , Iwnicki S D , Cavalletti M , de Vries E , Shahzad F , Evans G
Published: June 2009

This article describes a flexible track system model (FTSM) that represents the track structure for a typical ballasted track, taking into account the flexibility of the rails, the sleeper mass and the resilience of the pad/fastening elements, as well as the ballast support stiffness condition. The detailed track model is integrated into a commercial railway vehicle dynamics software, thus allowing for any vehicle to be simulated onto the flexible track while at the same time taking into account the detailed calculation of the non-linear wheel—rail contact interaction. As an example, the application of the FTSM to the study of hanging sleepers, with respect to the UK Railway Group Standard limits, is presented. This example shows the impact of forces because of hanging sleepers on the vehicle and on the track, and attempts at quantifying the damage made to the track components for the specific conditions simulated.
Characterization of a membraneless direct-methanol micro fuel cell
Authors: Sprague I B , Dutta P , Ha S
Published: June 2009

The performance of a membraneless laminar flow micro fuel cell was evaluated under different operating conditions. The fuel cell was microfabricated in polydimethylsiloxane using standard soft-lithography techniques. It used methanol solution as the fuel for the anode side, and oxygen saturated sulphuric acid for the cathode. The parameters studied were the methanol concentration, flowrate, device width, and the concentration of sulphuric acid in the anode stream. Performance was characterized by V— I plots, stability of open circuit potential (OCP), polarization resistances, and anode polarization curves. We observed behaviour different from that shown thus far by existing laminar flow fuel cells. Our results show that the power output of the device decreases with an increase in the methanol concentration. An increase in the flowrate also decreases the power output of the device. It is shown that these trends are likely caused by the cell's internal resistance to proton transport. The addition of sulphuric acid to the fuel significantly decreases this resistance. It was found that the device OCP was not stable over extended operation, and could drop by more than 150 mV in 72 h.
A comparison of the performance of a direct expansion solar assisted heat pump working with R22 and a mixture of R407C–liquefied petroleum gas
Authors: Mohanraj M , Jayaraj S , Muraleedharan C
Published: June 2009

In the present work, an experimental investigation has been made of a direct expansion solar assisted heat pump (DXSAHP) working with R22 and mixture of R407C–liquefied petroleum gas (LPG). The experiments were carried out under the meteorological conditions of Calicut (latitude of 11.15 °N, longitude of 75.49 °E), India. An artificial neural network model with two neurons (ambient temperature and solar intensity) in input layer and five neurons (instantaneous compressor power consumption (PC), heating capacity, energy performance ratio (equivalent to coefficient of performance), compressor discharge temperature, and solar energy input ratio (SEIPR)) in the output layer has been developed for predicting the performance of a DXSAHP based on the data acquired from the experiments. The results showed that R407C–LPG (in the ratio of 70:30, by mass) has 1.2 per cent higher instantaneous compressor PC with 1–4.5 per cent lower heating capacity compared to R22. The energy performance ratio (EPR) of the mixture was found to be lower in the range of 2–5 per cent compared to that of R22. The compressor discharge temperature was also found to be low by 2 °C compared to R22. The SEIPR of the new mixture was found to be higher than that of R22 in the range of 7–14 per cent. Total equivalent warming impact of new refrigerant mixture was found to be low compared to R22 under leakage conditions. The results confirmed that R407C–LPG is an ozone friendly alternative option to phase out R22 in solar assisted heat pump applications.
Alkali-ions diffusion, mullite formation, and crystals dissolution during sintering of porcelain bodies: Microstructural approach
Authors: Leonelli C , Kamseu E , Boccaccini D N , Sglavo V M , Pellacani G C
Published: June 2009

The effect of alkali-silicate glassy matrix as replacement for feldspar in soft and hard porcelain compositions was studied. SEM and X-ray diffraction analysis were used to evidence phase evolution. For each composition, the influence of soaking time was evaluated. The difference in chemical composition (amount of alkali and alumina) between the two types of porcelain studied influenced the final microstructure: density, pore size and shape, and mullite content. Quartz dissolution was more important in soft porcelain where the mullitization was limited by the low amount of alumina compared to hard porcelain. Replacing the feldspar by alkali-silicate glassy matrices with similar chemical composition, the amount of secondary mullite and mechanical properties increased in both soft and hard compositions.
The effect of post-weld heat treatments on the microstructure and mechanical properties of maraging steel laser weldments
Authors: Reddy G Madhusudhan , Rao V V , Raju A V S
Published: June 2009

The role of post-weld heat treatments on the microstructure and mechanical properties of maraging steel laser welds has been investigated. The post-weld heat treatments are (a) direct ageing at 480°C/3h/air cooling, (b) solutionizing at 815°C/1h/air cooling+at 480°C/3h/air cooling, and (c) homogenization at 1150°C/1h/air cooling+solutionizing at 815°C/1h/air cooling+ageing at 480°C/3h/air cooling. The welded+aged and welded+solutionized+aged microstructure consisting of reverted austenite exhibited low strength and toughness. Homogenization treatment resulted in a microstructure free from reverted austenite and subsequent solutionizing and ageing resulted in improved strength and impact toughness.
Physical programming and conjoint analysis-based redundancy allocation in multistate systems: A Taguchi embedded algorithm selection and control (TAS&C) approach
Authors: Kumar V V , Tripathi M , Pandey M K , Tiwari M K
Published: June 2009

Amidst increasing system complexity and technological advancements, the manufacturer aims to win the consumer's trust to maintain his or her permanent goodwill. This expectation directs the manufacturer to address the problem of attaining desired quality and reliability standards; hence, the measure of performance of a system in terms of reliability and utility optimization poses an issue of primary concern. In order to meet the requirement of a reliable and trouble-free product, optimal allocation of all conflicting parameters is essential during the design phase of a system. With this in mind, this paper presents a physical programming and conjoint analysis-based redundancy allocation model (PPCA-RAM) for a multistate series—parallel system. Use of physical programming approach is the key feature of the proposed algorithm to eliminate the need for multi-objective optimization. Physical programming methodology provides an adequate balance among various associated performance measures and thus provides an efficient tool for formulating the objective function of a practical redundancy allocation problem. The proposed model has been addressed by a novel methodology called Taguchi embedded algorithm selection and control (TAS&C). An illustrative example has been presented to authenticate the efficiency of the proposed model and algorithm. The results obtained are compared with the genetic algorithm (GA), artificial immune system (AIS), and particle swarm optimization (PSO), where TAS&C was seen to significantly outperform the rest.
Improved utility and application of probabilistic methods for reliable mechanical design
Authors: Goh Y M , McMahon C A , Booker J D
Published: June 2009

In a modern product development process such as in the automotive and aerospace sectors, extensive analytical and simulation approaches often are used to assess the ability of a design in fulfilling its requirements. Consideration of uncertainty in such situations is critical in ensuring a reliable design is produced. Probabilistic methods facilitate an improved understanding of design performance through characterization of uncertainty in the design parameters. The probabilistic methods developed over the past several decades have a range of capabilities and modes of application, for example, to predict reliability, for optimization, and to perform sensitivity studies, but have yet to be taken up routinely by industry due to a number of reasons. In this paper, issues that have typically inhibited their use or prevented a successful outcome are addressed through a systematic framework for improved utility and successful application of probabilistic designing for mechanical reliability.
Determination of fibroblast growth factor 23
Authors: Heijboer Annemieke C , Levitus Marieke , Vervloet Marc G , Lips Paul , Wee Piet M ter , Dijstelbloem Hilde M , Blankenstein Marinus A
Published: June 2009

Background

Fibroblast growth factor 23 (FGF-23) is a recently discovered hormone, which plays a key role in phosphate regulation. To investigate whether FGF-23 can be determined reliably, we validated the three available FGF-23 assays.

Methods

Currently, two intact FGF-23 assays (Kainos; Immutopics) and one C-terminal FGF-23 assay (Immutopics) are available. We determined intra- and inter-assay variation, linearity and matrix interference in these assays. Moreover, we compared assay results from healthy subjects with those of patient groups with expected high FGF-23 concentrations.

Results

Intra-assay variation was reasonably good in all three assays. Inter-assay variation and linearity were poor for the intact Immutopics assay but reasonable for both other assays. Immutopics assays gave best results in ethylenediaminetetraacetic acid (EDTA) plasma, while the Kainos assay showed comparable reproducibility in EDTA plasma and serum. Although the manual of the Kainos assay states that an automatic washing machine can be used, acceptable results were only found by manual washing. Patients with kidney disease and patients with hypophosphatemic osteomalacia had increased C-terminal FGF-23 concentrations compared with healthy controls.

Conclusion

Two assays of reasonable quality are available for FGF-23, the intact FGF-23 assay (Kainos) provided proper attention is paid to the washing procedure, and the C-terminal assay (Immutopics).
Feasibility and Constraint Analysis of Sets of Linear Matrix Inequalities
Authors: Caron Richard J. , Traynor Tim , Jibrin Shafiu
Published: June 2009

We present a constraint analysis methodology for linear matrix inequality constraints. If the constraint set is found to be feasible, we search for a minimal representation; otherwise, we search for an irreducible infeasible system. The work is based on the solution of a set-covering problem where each row corresponds to a sample point and is determined by constraint satisfaction at the sampled point. Thus, an implementation requires a method to collect points in the ambient space and a constraint oracle. Much of this paper will be devoted to the development of a hit-and-run sampling methodology. Test results confirm that our approach not only provides information required for constraint analysis but will also, if the feasible region has a nonvoid interior, with probability one, find a feasible point.
Numerically Safe Gomory Mixed-Integer Cuts
Authors: Cook William , Dash Sanjeeb , Fukasawa Ricardo , Goycoolea Marcos
Published: June 2009

We describe a simple process for generating numerically safe cutting planes using floating-point arithmetic and the mixed-integer rounding procedure. Applying this method to the rows of the simplex tableau permits the generation of Gomory mixed-integer cuts that are guaranteed to be satisfied by all feasible solutions to a mixed-integer programming problem (MIP). We report on tests with the MIPLIB 3.0 and MIPLIB 2003 test collections as well as with MIP instances derived from the TSPLIB traveling salesman library.
An Inexact Bundle Approach to Cutting-Stock Problems
Authors: Kiwiel Krzysztof C.
Published: June 2009

We show that the linear programming relaxation of the cutting-stock problem can be solved efficiently by the recently proposed inexact bundle method. This method saves work by allowing inaccurate solutions to knapsack subproblems. With suitable rounding heuristics, our method solves almost all the cutting-stock instances from the literature.
Sequential Sampling to Myopically Maximize the Expected Value of Information
Authors: Chick Stephen E. , Branke Jürgen , Schmidt Christian
Published: June 2009

Statistical selection procedures are used to select the best of a finite set of alternatives, where “best” is defined in terms of each alternative's unknown expected value, and the expected values are inferred through statistical sampling. One effective approach, which is based on a Bayesian probability model for the unknown mean performance of each alternative, allocates samples based on maximizing an approximation to the expected value of information (EVI) from those samples. The approximations include asymptotic and probabilistic approximations. This paper derives sampling allocations that avoid most of those approximations to the EVI but entails sequential myopic sampling from a single alternative per stage of sampling. We demonstrate empirically that the benefits of reducing the number of approximations in the previous algorithms are typically outweighed by the deleterious effects of a sequential one-step myopic allocation when more than a few dozen samples are allocated. Theory clarifies the derivation of selection procedures that are based on the EVI.
Synthetic Optimization Problem Generation: Show Us the Correlations!
Authors: Reilly Charles H.
Published: June 2009

In many computational experiments, correlation is induced between certain types of coefficients in synthetic (or simulated) instances of classical optimization problems. Typically, the correlations that are induced are only qualified—that is, described by their presumed intensity. We quantify the population correlations induced under several strategies for simulating 0–1 knapsack problem instances and also for correlation-induction approaches used to simulate instances of the generalized assignment, capital budgeting (or multidimensional knapsack), and set-covering problems. We discuss implications of these correlation-induction methods for previous and future computational experiments on simulated optimization problems.
Branch and Cut and Price for the Pickup and Delivery Problem with Time Windows
Authors: Ropke Stefan , Cordeau Jean-François
Published: June 2009

In the pickup and delivery problem with time windows vehicle routes must be designed to satisfy a set of transportation requests, each involving a pickup and delivery location, under capacity, time window, and precedence constraints. This paper introduces a new branch-and-cut-and-price algorithm in which lower bounds are computed by solving through column generation the linear programming relaxation of a set partitioning formulation. Two pricing subproblems are considered in the column generation algorithm: an elementary and nonelementary shortest path problem. Valid inequalities are added dynamically to strengthen the relaxations. Some of the previously proposed inequalities for the pickup and delivery problem with time windows are also shown to be implied by the set partitioning formulation. Computational experiments indicate that the proposed algorithm outperforms a recent branch-and-cut algorithm.
Lengthening of the congenital short femur using the Ilizarov technique
Authors: Aston W. J. S. , Calder P. R. , Baker D. , Hartley J. , Hill R. A.
Published: June 2009

We present a retrospective review of a single-surgeon series of 30 consecutive lengthenings in 27 patients with congenital short femur using the Ilizarov technique performed between 1994 and 2005.

The mean increase in length was 5.8 cm/18.65% (3.3 to 10.4, 9.7% to 48.8%), with a mean time in the frame of 223 days (75 to 363). By changing from a distal to a proximal osteotomy for lengthening, the mean range of knee movement was significantly increased from 98.1° to 124.2° (p = 0.041) and there was a trend towards a reduced requirement for quadricepsplasty, although this was not statistically significant (p = 0.07). The overall incidence of regenerate deformation or fracture requiring open reduction and internal fixation was similar in the distal and proximal osteotomy groups (56.7% and 53.8%, respectively). However, in the proximal osteotomy group, pre-placement of a Rush nail reduced this rate from 100% without a nail to 0% with a nail (p < 0.001). When comparing a distal osteotomy with a proximal one over a Rush nail for lengthening, there was a significant decrease in fracture rate from 58.8% to 0% (p = 0.043).

We recommend that in this group of patients lengthening of the femur with an Ilizarov construct be carried out through a proximal osteotomy over a Rush nail. Lengthening should also be limited to a maximum of 6 cm during one treatment, or 20% of the original length of the femur, in order to reduce the risk of complications.
The reliability and accuracy of digital templating in total knee replacement
Authors: Trickett R. W. , Hodgson P. , Forster M. C. , Robertson A.
Published: June 2009

We aimed to determine the reliability, accuracy and the clinical role of digital templating in the pre-operative work-up for total knee replacement.

Initially a sample of ten pre-operative digital radiographs were templated by four independent observers to determine the inter- and intra-observer reliability of the process. Digital templating was then performed on the radiographs of 40 consecutive patients undergoing total knee replacement by a consultant surgeon not involved with the operation, who was blinded to the size of the implant inserted. The Press Fit Condylar Sigma Knee system was used in all the patients. The size of the implant as judged by templating was then compared to that of the size used.

Good inter- and intra-observer agreement was demonstrated for both femoral and tibial templating. However, the correct size of the implant was predicted in only 48% of the femoral and 55% of the tibial components. Albeit reproducible, digital templating does not currently predict the correct size of component often enough to be of clinical benefit.
A comparison of regional and general anaesthesia for total replacement of the hip or knee
Authors: Hu S. , Zhang Z.-Y. , Hua Y.-Q. , Li J. , Cai Z.-D.
Published: June 2009

We performed a meta-analysis to evaluate the relative efficacy of regional and general anaesthesia in patients undergoing total hip or knee replacement. A comprehensive search for relevant studies was performed in PubMed (1966 to April 2008), EMBASE (1969 to April 2008) and the Cochrane Library. Only randomised studies comparing regional and general anaesthesia for total hip or knee replacement were included.

We identified 21 independent, randomised clinical trials. A random-effects model was used to calculate all effect sizes. Pooled results from these trials showed that regional anaesthesia reduces the operating time (odds ratio (OR) −0.19; 95% confidence interval (CI) −0.33 to −0.05), the need for transfusion (OR 0.45; 95% CI 0.22 to 0.94) and the incidence of thromboembolic disease (deep-vein thrombosis OR 0.45, 95% CI 0.24 to 0.84; pulmonary embolism OR 0.46, 95% CI 0.29 to 0.80).

Regional anaesthesia therefore seems to improve the outcome of patients undergoing total hip or knee replacement.
Survival and clinical function of cemented and uncemented prostheses in total knee replacement
Authors: Gandhi R. , Tsvetkov D. , Davey J. R. , Mahomed N. N.
Published: June 2009

Using meta-analysis we compared the survival and clinical outcomes of cemented and uncemented techniques in primary total knee replacement. We reviewed randomised controlled trials and observational studies comparing cemented and uncemented fixation. Our primary outcome was survival of the implant free of aseptic loosening. Our secondary outcome was joint function as measured by the Knee Society score. We identified 15 studies that met our final eligibility criteria. The combined odds ratio for failure of the implant due to aseptic loosening for the uncemented group was 4.2 (95% confidence interval (CI) 2.7 to 6.5) (p < 0.0001). Subgroup analysis of data only from randomised controlled trials showed no differences between the groups for odds of aseptic loosening (odds ratio 1.9, 95% CI 0.55 to 6.40, p = 0.314). The weighted mean difference for the Knee Society score was 0.005 (95% CI −0.26 to 0.26) (p = 0.972).

There was improved survival of the cemented compared to uncemented implants, with no statistically significant difference in the mean Knee Society score between groups for all pooled data.
Lengthening of subscapularis and transfer of the lower trapezius in the correction of recurrent internal rotation contracture following obstetric brachial plexus palsy
Authors: Bertelli J. A.
Published: June 2009

An internal rotation contracture is a common complication of obstetric brachial plexus palsy. We describe the operative treatment of seven children with a recurrent internal rotation contracture of the shoulder following earlier corrective surgery which included subscapularis slide and latissimus dorsi transfer. We performed z-lengthening of the tendon of the subscapularis muscle and transferred the lower trapezius muscle to the infraspinatus tendon. Two years postoperatively the mean gain in active external rotation was 47.1°, which increased to 54.3° at four years.

Lengthening of the tendon of subcapularis and lower trapezius transfer to infraspinatus improved the range of active external rotation in patients who had previously had surgery for an internal rotation contracture.
The medial periosteal hinge, a key structure in fractures of the proximal humerus
Authors: Kralinger F. , Unger S. , Wambacher M. , Smekal V. , Schmoelz W.
Published: June 2009

The medial periosteal hinge plays a key role in fractures of the head of the humerus, offering mechanical support during and after reduction and maintaining perfusion of the head by the vessels in the posteromedial periosteum. We have investigated the biomechanical properties of the medial periosteum in fractures of the proximal humerus using a standard model in 20 fresh-frozen cadaver specimens comparable in age, gender and bone mineral density. After creating the fracture, we displaced the humeral head medial or lateral to the shaft with controlled force until complete disruption of the posteromedial periosteum was recorded. As the quality of periosteum might be affected by age and bone quality, the results were correlated with the age and the local bone mineral density of the specimens measured with quantitative CT.

Periosteal rupture started at a mean displacement of 2.96 mm (sd 2.92) with a mean load of 100.9 N (sd 47.1). The mean maximum load of 111.4 N (sd 42.5) was reached at a mean displacement of 4.9 mm (sd 4.2). The periosteum was completely ruptured at a mean displacement of 34.4 mm (sd 11.1). There was no significant difference in the mean distance to complete rupture for medial (mean 35.8 mm (sd 13.8)) or lateral (mean 33.0 mm (sd 8.2)) displacement (p = 0.589).

The mean bone mineral density was 0.111 g/cm3 (sd 0.035). A statistically significant but low correlation between bone mineral density and the maximum load uptake (r = 0.475, p = 0.034) was observed.

This study showed that the posteromedial hinge is a mechanical structure capable of providing support for percutaneous reduction and stabilisation of a fracture by ligamentotaxis. Periosteal rupture started at a mean of about 3 mm and was completed by a mean displacement of just under 35 mm. The microvascular situation of the rupturing periosteum cannot be investigated with the current model.
A dual anteroposterior approach to the Bernese periacetabular osteotomy
Authors: Kim H. T. , Woo S. H. , Lee J. S. , Cheon S. J.
Published: June 2009

When the Bernese periacetabular osteotomy is performed through an anterior approach, the ischial and retroacetabular osteotomies and manual fracture of the incompletely osteotomised ischium are conducted with an incomplete view resulting in increased risk and morbidity. We have assessed the dual anteroposterior approach which appears to address this deficiency.

We compared the results of the Bernese periacetabular osteotomy performed in 11 patients (13 osteotomies) through a single anterior approach with those in 12 patients (13 osteotomies) in whom the procedure was carried out through a dual anteroposterior approach. The estimated blood loss, the length of anaesthesia, duration of surgery and radiological parameters were measured.

The mean operative time and length of anaesthesia were not significantly different in the two groups (p = 0.781 and p = 0.698, respectively). The radiological parameters improved to a similar extent in both groups after the operation but there was significantly less blood loss in the dual osteotomy group (p = 0.034).

The dual anteroposterior approach provides a direct view of the retroacetabular and ischial parts of the osteotomy, within a reasonable operating time and with minimal blood loss and gives a satisfactory outcome.
The incidence of physiological radiolucency following Oxford unicompartmental knee replacement and its relationship to outcome
Authors: Gulati A. , Chau R. , Pandit H. G. , Gray H. , Price A. J. , Dodd C. A. F. , Murray D. W.
Published: June 2009

Narrow, well-defined radiolucent lines commonly observed at the bone-implant interface of unicompartmental knee replacement tibial components have been referred to as physiological radiolucencies. These should be distinguished from pathological radiolucencies, which are poorly defined, wide and progressive, and associated with loosening and infection. We studied the incidence and clinical significance of tibial radiolucent lines in 161 Oxford unicondylar knee replacements five years after surgery. All the radiographs were aligned with fluoroscopic control to obtain views parallel to the tibial tray to reveal the tibial bone-implant interface.

We found that 49 knees (30%) had complete, 52 (32%) had partial and 60 (37%) had no radiolucent lines. There was no relationship between the incidence of radiolucent lines and patient factors such as gender, body mass index and activity, or operative factors including the status of the anterior cruciate ligament and residual varus deformity. Nor was any statistical relationship established between the presence of radiolucent lines and clinical outcome, particularly pain, assessed by the Oxford Knee score and the American Knee Society score.

We conclude that radiolucent lines are common after Oxford unicompartmental knee replacement but that their aetiology remains unclear. Radiolucent lines were not a source of adverse symptoms or pain. Therefore, when attempting to identify a source of postoperative pain after Oxford unicompartmental knee replacement the presence of a physiological radiolucency should be ignored.
The Morscher Press Fit acetabular component
Authors: Gwynne-Jones D. P. , Garneti N. , Wainwright C. , Matheson J. A. , King R.
Published: June 2009

We reviewed the results at nine to 13 years of 125 total hip replacements in 113 patients using the monoblock uncemented Morscher press-fit acetabular component. The mean age at the time of operation was 56.9 years (36 to 74). The mean clinical follow-up was 11 years (9.7 to 13.5) and the mean radiological follow-up was 9.4 years (7.7 to 13.1). Three hips were revised, one immediately for instability, one for excessive wear and one for deep infection.

No revisions were required for aseptic loosening. A total of eight hips (7.0%) had osteolytic lesions greater than 1 cm, in four around the acetabular component (3.5%). One required bone grafting behind a well-fixed implant. The mean wear rate was 0.11 mm/year (0.06 to 0.78) and was significantly higher in components with a steeper abduction angle.

Kaplan-Meier survival curves at 13 years showed survival of 96.8% (95% confidence interval 90.2 to 99.0) for revision for any cause and of 95.7% (95% confidence interval 88.6 to 98.4) for any acetabular re-operation.
The principle of low frictional torque in the Charnley total hip replacement
Authors: Wroblewski B. M. , Siney P. D. , Fleming P. A.
Published: June 2009

The design of the Charnley total hip replacement follows the principle of low frictional torque. It is based on the largest possible difference between the radius of the femoral head and that of the outer aspect of the acetabular component. The aim is to protect the bone-cement interface by movement taking place at the smaller radius, the articulation. This is achieved in clinical practice by a 22.225 mm diameter head articulating with a 40 mm or 43 mm diameter acetabular component of ultra-high molecular weight polyethylene.

We compared the incidence of aseptic loosening of acetabular components with an outer diameter of 40 mm and 43 mm at comparable depths of penetration with a mean follow-up of 17 years (1 to 40).

In cases with no measurable wear none of the acetabular components were loose. With increasing acetabular penetration there was an increased incidence of aseptic loosening which reflected the difference in the external radii, with 1.5% at 1 mm, 8.8% at 2 mm, 9.7% at 3 mm and 9.6% at 4 mm of penetration in favour of the larger 43 mm acetabular component.

Our findings support the Charnley principle of low frictional torque. The level of the benefit is in keeping with the predicted values.
Acetabular revision using an anti-protrusion (ilio-ischial) cage and trabecular metal acetabular component for severe acetabular bone loss associated with pelvic discontinuity
Authors: Kosashvili Y. , Backstein D. , Safir O. , Lakstein D. , Gross A. E.
Published: June 2009

Pelvic discontinuity with associated bone loss is a complex challenge in acetabular revision surgery. Reconstruction using ilio-ischial cages combined with trabecular metal acetabular components and morsellised bone (the component-cage technique) is a relatively new method of treatment.

We reviewed a consecutive series of 26 cases of acetabular revision reconstructions in 24 patients with pelvic discontinuity who had been treated by the component-cage technique. The mean follow-up was 44.6 months (24 to 68). Failure was defined as migration of a component of > 5 mm.

In 23 hips (88.5%) there was no clinical or radiological evidence of loosening at the last follow-up. The mean Harris hip score improved significantly from 46.6 points (29.5 to 68.5) to 76.6 points (55.5 to 92.0) at two years (p < 0.001). In three hips (11.5%) the construct had migrated at one year after operation. The complications included two dislocations, one infection and one partial palsy of the peroneal nerve.

Our findings indicate that treatment of pelvic discontinuity using the component-cage construct is a reliable option.
Comparison of periacetabular osteotomy and total hip replacement in the same patient
Authors: Hsieh P.-H. , Huang K.-C. , Lee P.-C. , Chang Y.-H.
Published: June 2009

We evaluated 31 patients with bilateral dysplastic hips who had undergone periacetabular osteotomy for early (Tönnis grade 0 or 1) or moderate (Tönnis grade 2) osteoarthritis in one hip and total hip replacement for advanced (Tönnis grade 3) osteoarthritis in the other. At a mean follow-up of 5.5 years (2 to 9) after periacetabular osteotomy and 6.7 years (3 to 10) after total hip replacement, there was no difference in the functional outcome in hips undergoing osteotomy for early or moderate osteoarthritis and those with a total hip replacement, as determined by the Merle d’Aubigné and Postel score and the Western Ontario and McMaster Universities osteoarthritis index. More patients preferred the spherical periacetabular osteotomy to total hip replacement (53% vs 23%; p = 0.029). Osteoarthritis secondary to hip dysplasia is often progressive. Given the results, timely correction of dysplasia by periacetabular osteotomy should be considered whenever possible in young patients since this could produce a favourable outcome which is comparable with that of total hip replacement.
Hydroxyapatite-ceramic-coated femoral components in young patients followed-up for 16 to 19 years
Authors: Shah N. N. , Edge A. J. , Clark D. W.
Published: June 2009

In 2004 we described the ten-year prospective results of 38 total hip replacements using the Furlong hydroxyapatite-ceramic-coated femoral component in 35 patients < 50 years old. We have now reviewed the surviving 35 arthroplasties in 33 patients at a mean of 16 years (10.3 to 19.9). The mean age of the surviving patients at the time of operation was 41.3 years (26.0 to 49.0). Of these, eight have undergone revision of their acetabular component for aseptic loosening. None of the femoral components has had revision for aseptic loosening giving a survival rate of 100% at 16 years (95% confidence interval 89% to 100%).

The Furlong hydroxyapatite-ceramic-coated femoral component gives excellent long-term survival in young and active patients.
Genetic influences in the progression of tears of the rotator cuff
Authors: Gwilym S. E. , Watkins B. , Cooper C. D. , Harvie P. , Auplish S. , Pollard T. C. B. , Rees J. L. , Carr A. J.
Published: June 2009

The aim of this study was to investigate genetic influences on the development and progression of tears of the rotator cuff. From a group of siblings of patients with a tear of the rotator cuff and of controls studied five years earlier, we determined the prevalence of tears of the rotator cuff with and without associated symptoms using ultrasound and the Oxford Shoulder Score.

In the five years since the previous assessment, three of 62 (4.8%) of the sibling group and one of the 68 (1.5%) controls had undergone shoulder surgery. These subjects were excluded from the follow-up.

Full-thickness tears were found in 39 of 62 (62.9%) siblings and in 15 of 68 (22.1%) controls (p = 0.0001). The relative risk of full-thickness tears in siblings as opposed to controls was 2.85 (95% confidence interval (CI) 1.75 to 4.64), compared to 2.42 (95% CI 1.77 to 3.31) five years earlier. Full-thickness tears associated with pain were found in 30 of 39 (76.9%) tears in the siblings and in eight of 15 (53.3%) tears in the controls (p = 0.045). The relative risk of pain associated with a full-thickness tear in the siblings as opposed to the controls was 1.44 (95% CI 2.04 to 8.28) (p = 0.045).

In the siblings group ten of 62 (16.1%) had progressed in terms of tear size or development compared to one of 68 (1.5%) in the control group which had increased in size.

Full-thickness rotator cuff tears in siblings are significantly more likely to progress over a period of five years than in a control population. This implies that genetic factors have a role, not only in the development but also in the progression of full-thickness tears of the rotator cuff.
Severe periprosthetic osteolytic lesions after the Ankle Evolutive System total ankle replacement
Authors: Koivu H. , Kohonen I. , Sipola E. , Alanen K. , Vahlberg T. , Tiusanen H.
Published: June 2009

Between 2002 and 2008, 130 consecutive ankles were replaced with an hydroxyapatite (HA) and titanium-HA-coated Ankle Evolutive System total ankle prosthesis. Plain radiographs were analysed by two independent observers. Osteolytic lesions were classified by their size and location, with cavities > 10 mm in diameter considered to be ‘marked’. CT scanning was undertaken in all patients with marked osteolysis seen on the plain radiographs.

Osteolytic lesions were seen on the plain films in 48 (37%) and marked lesions in 27 (21%) ankles. The risk for osteolysis was found to be 3.1 (95% confidence interval 1.6 to 5.9) times higher with implants with Ti-HA porous coating.

Care should be taken with ankle arthroplasty until more is known about the reasons for these severe osteolyses.
Length of stay, mortality, morbidity and delay to surgery in hip fractures
Authors: Lefaivre K. A. , Macadam S. A. , Davidson D. J. , Gandhi R. , Chan H. , Broekhuyse H. M.
Published: June 2009

Our aim was to determine the effect of delay to surgery on the time to discharge, in-hospital death, the presence of major and minor medical complications and the incidence of pressure sores in patients with a fracture of the hip. All patients admitted to Vancouver General Hospital with this injury between 1998 and 2001 inclusive were identified from our trauma registry. A review of the case notes was performed to determine the delay in time from admission to surgery, age, gender, type of fracture and medical comorbidities. A time-to-event analysis was performed for length of stay. Additionally, a Cox proportional hazards model was used to determine the effect of delay to surgery on the length of stay while controlling for other pertinent confounding factors. Using logistical regression we determined the effect of delay to surgery on in-hospital death, medical complications and the presence of pressure sores, while controlling for confounding factors.

Delay to surgery (p = 0.0255), comorbidity (p < 0.0001), age (p < 0.0001) and type of fracture (p = 0.0004) were all significant in the Cox proportional hazards model for increased time to discharge. Delay to surgery was not a significant predictor of in-hospital mortality. However, a delay of more than 24 hours was a significant predictor of a minor medical complication (odds ratio (OR) 1.53, 95% confidence interval (CI) 1.05 to 2.22), while a delay of more than 48 hours was associated with an increased risk of a major medical complication (OR 2.21, 95% CI 1.01 to 4.34), a minor medical complication (OR 2.27, 95% CI 1.38 to 3.72) and of pressure sores (OR 2.29, 95% CI 1.19 to 4.40).

Patients with a fracture of the hip should have surgery early to lessen the time to acute-care hospital discharge and to minimise the risk of complications.
Whiplash injury
Authors: Bannister G. , Amirfeyz R. , Kelley S. , Gargan M.
Published: June 2009

This review discusses the causes, outcome and prevention of whiplash injury, which costs the economy of the United Kingdom approximately £3.64 billion per annum. Most cases occur as the result of rear-end vehicle collisions at speeds of less than 14 mph. Patients present with neck pain and stiffness, occipital headache, thoracolumbar back pain and upper-limb pain and paraesthesia. Over 66% make a full recovery and 2% are permanently disabled. The outcome can be predicted in 70% after three months.
How Normative Information Shapes Attributions for the Actions of Persons With Traumatic Brain Injury
Authors: McClure John , Abbott Joanne
Published: June 2009

Many citizens misunderstand the actions of persons with brain injury, and these misunderstandings hamper rehabilitation. A specific misunderstanding is where people misattribute behaviours resulting from brain injury to the injured person's personality or life stage (e.g., adolescence). The present study examined if this pattern is explained by the Abnormal Conditions Focus model of attribution, which claims that attributions for behaviours reflect whether the behaviours are normal for the person (Consistency) and the culture (Consensus). Scenarios described an adolescent with brain injury performing four undesirable behaviours and then indicated whether the behaviour was normal or not normal for the person prior to injury and normal or not normal for that person's culture. For each of the four behaviours, students (n = 136) rated three attributions: brain injury, personality and adolescent norms. Participants attributed the behaviours more to brain injury and less to personality when the behaviours were not normal for that person than when they were normal for the person. They attributed the behaviours more to adolescence when the behaviours were normal for the person's culture than when they were not normal for the culture. Rehabilitation implications include assessing individuals' premorbid behaviour to enable citizens and less experienced professionals to make more accurate attributions for behaviours and target treatment more effectively.
Christian song in a global church: The role of musical structure in community formation
Authors: Hawn C. Michael
Published: June 2009

While recognizing the importance of musical style in congregational singing, this article suggests that the underlying structure of the people's song influences how they receive theology and the relationship of song to ritual action. The author, after introducing sequential, cyclic and refrain structures, defines the characteristics of each and proposes ways that each structure may enliven a ritual and enable community building.
Ritual community and identity formation: A case study of the Thai Covenant Church in Thailand
Authors: Hong Lim Swee
Published: June 2009

This essay seeks to showcase the emerging efforts of the Christian church in Asia to recover her indigenous voice in worship through contextualized Christian ritual praxis and music making. Through the life and ministry of the Thai Covenant Church, we examine its significance to the
formation of a community of faith.
A musical ichthus: Praise & worship and Evangelical identity
Authors: Scheer Greg
Published: June 2009

The author draws on his own experiences as a church music practitioner to explore the relationship between the Evangelical Christian community and the contemporary Praise and Worship music genre.
Book Review
Authors: Brown Melanie
Published: June 2009

A Fusion of Traditions: Liturgical Music in the Copenhagen Synagogue, Jane Mink Rossen & Uri Sharvit (2006) University Press of Southern Denmark, ISBN 87-7674-038-2, nnn pp.156, paperback, price E 28.30
Application of numerical continuation to compute all solutions of semilinear elliptic equations
Authors: Allgower Eugene , Cruceanu Stefan-Gicu , Tavener Simon
Published: June 2009

We adapt numerical continuation methods to compute all solutions of finite difference discretizations of nonlinear boundary value problems involving the Laplacian in two dimensions. New solutions on finer meshes are obtained from solutions on coarser meshes using a complex homotopy deformation. Two difficulties arise. First, the number of solutions typically grows with the number of mesh points and some form of filtering becomes necessary. Secondly, bifurcations may occur along homotopy paths of solutions and efficient methods to swap branches are developed when the mappings are analytic. For polynomial nonlinearities we generalize an earlier strategy for finding all solutions of two-point boundary value problems in one dimension and then introduce exclusion algorithms to extend the method to general nonlinearities.
Unstable minimal surfaces of annulus type in manifolds
Authors: Kim Hwajeong
Published: June 2009

Unstable minimal surfaces are the unstable stationary points of the Dirichlet integral. In order to obtain unstable solutions, the method of the gradient flow together with the minimax-principle is generally used, an application of which was presented in [Struwe, J. Reine Angew. Math. 349: 1–23, 1984] for minimal surfaces in Euclidean space. We extend this theory to obtain unstable minimal surfaces in Riemannian manifolds. In particular, we consider minimal surfaces of annulus type.
Constructing simplicial branched covers
Authors: Witte Nikolaus
Published: June 2009

Izmestiev and Joswig described how to obtain a simplicial covering space (the partial unfolding) of a given simplicial complex, thus obtaining a simplicial branched cover [Adv. Geom. 3:191–255, 2003]. We present a large class of branched covers which can be constructed via the partial unfolding. In particular, for d ≤ 4 every closed oriented PL d-manifold is the partial unfolding of some polytopal d-sphere.
Tangential connection
Authors: Mella Massimiliano
Published: June 2009

Let X ⊂ be a smooth variety. The embedding in gives naturally rise to the notion of embedded tangent spaces. That is the locus spanned by tangent lines to a point x ∈ X. Generally the embedded tangent space intersects the variety X only at the point x. In this paper I am interested in those X for which this intersection, for x ∈ X general, is a positive dimensional subvariety. The results of this paper support the conjecture that these varieties are built out of some special varieties.
Review of Multiaxis Fatigue Testing for Fatigue/Durability of Cardiovascular Medical Devices
Authors: Anderson Scott
Published: June 2009

The use of nitinol stents in the superficial femoral artery (SFA) is becoming commonplace. The SFA is a tortuous biomechanical environment that has challenged the durability of these devices. A thorough understanding of the biomechanical loading environment is necessary to design and evaluate new stents. This paper reports recent methods for use of bench testing as a tool to predict fatigue fracture of stents for complex multimode duty cycles.
Overview of Pearlitic Rail Steel: Accelerated Cooling, Quenching, Microstructure, and Mechanical Properties
Authors: Sahay Satyam S. , Mohapatra Goutam , Totten George E.
Published: June 2009

Railway networks form an integral part of the infrastructure development of a developing country with ever-increasing passenger and freight volume. Increase in train speed, pay load, reliability, and safety are the major thrust areas for railways requiring more stringent mechanical properties such as wear, deformation resistance, and fatigue life from the railway steel. Steel chemistry control and thermomechanical processing significantly affect final properties and performance of the railway steel. For example, for a given steel composition, a number of stable or metastable microstructures can be obtained by controlling heat treatment operations. Conventional rail steels primarily contain nearly eutectoid pearlitic microstructure, which is dependent on the criticality of the application. An overview of the physical metallurgy principles involved during the manufacturing of rail steel will be provided here. The primary focus of this review is thermal processing including quenching and accelerated cooling of the rail steel. In addition, other important aspects relating to design and production of rail steel are discussed, including: impact of steel chemistry on the phase diagram, effect of thermomechanical processing on microstructure, and influence of microstructure or residual stress on mechanical properties.