bluuebunny/crossref_metadata_2025 huggingface dataset:
Human treadmill walking needs attention
Authors: Regnaux Jean Philippe , Robertson Johanna , Smail Djamel Ben , Daniel Olivier , Bussel Bernard
Published: August 2006

Background

The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive) RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor) task. Varying the level of difficulty of the reaction time (RT) task is used to verify the priority of allocation of attentional resources.

Methods

11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration.

Results

Gait cycle duration was unchanged (p > 0.05) by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p < 0.01) indicating that an increased amount of resources are required for the maintainance of walking performance on a treadmill at a steady state. No interaction (p > 0.05) was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance.

Conclusion

We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.
Validity of air-displacement plethysmography in the assessment of body composition changes in a 16-month weight loss program
Authors: Minderico Cláudia S , Silva Analiza M , Teixeira Pedro J , Sardinha Luis B , Hull Holly R , Fields David A
Published: August 2006

Objective

To compare the accuracy of air displacement plethysmography (ADP) and dual energy x-ray absorptionmetry (DXA) in tracking changes in body composition after a 16 month weight loss intervention in overweight and obese females.

Methods

93 healthy female subjects (38.9 ± 5.7 yr, 159.8 ± 5.6 cm, 76.7 ± 9.9 kg, 30.0 ± 3.4 kg/m2) completed a 16 month weight loss intervention. Eligible subjects attended 15 treatment sessions occurring over the course of 4 months with educational content including topics relating to physical activity and exercise, diet and eating behavior, and behavior modification. In the remaining 12 months, subjects underwent a lifestyle program designed to increase physical activity and improve eating habits. Before and after the intervention, subjects had their percent body fat (%fat), fat mass (FM), and fat-free mass (FFM)) assessed by DXA and ADP.

Results

Significant differences (p ≤ 0.001) were found between DXA and ADP at baseline %fat (46.0 % fatvs. 42.0 % fat), FM (35.3 kgvs. 32.5 kg) and FFM (40.8 kgvs. 44.2 kg) as well as at post intervention for %fat (42.1% fatvs. 38.3 % fat), FM (30.9 kgvs. 28.4 kg) and FFM (41.7 kgvs. 44.7 kg). At each time point, ADP %fat and total FM was significantly lower (p ≤ 0.001) than DXA while FFM was significantly higher (p ≤ 0.001). However, both techniques tracked %fat changes similarly considering that there were no differences between the two means. Furthermore, a Bland-Altman analysis was performed and no significant bias was observed, thus demonstrating the ability of ADP to measure body fat across a wide range of fatness.

Conclusion

At baseline and post weight loss, a significant difference was found between ADP and DXA. However, the results indicate both methods are highly related and track changes in %fat similarly after a weight loss program in overweight and obese females. Additionally, the mean changes in %fat were similar between the two techniques, suggesting that ADP can be translated to its use in clinical practice and research studies as DXA currently is used.
In vitro hydrodynamic properties of the Miethke proGAV hydrocephalus shunt
Authors: Allin David M , Czosnyka Zofia H , Czosnyka Marek , Richards Hugh K , Pickard John D
Published: August 2006

Background

Adjustable shunts are very popular in the management of hydrocephalus and are believed to help in minimizing the number of surgical revisions. The drawback with almost all constructions is that they may be accidentally readjusted in relatively weak magnetic fields (around 30–40 mTesla)

Materials and methods

The ProGav Miethke shunt is composed of an adjustable ballon-spring valve unit and an integrated over-drainage compensating gravitational device (known as the shunt assistant). A mechanical 'brake' is intended to prevent changes to the valve's performance level in a strong magnetic field. We evaluated the performance and hydrodynamic properties of a sample of three valves in the UK Shunt Evaluation Laboratory.

Results

All the shunts showed good mechanical durability over the three-month period of testing, and good stability of hydrodynamic performance over a one-month period

The pressure-flow performance curves, operating, opening and closing pressures fell within the limits specified by the manufacturer, and changed according to the programmed performance levels. The operating pressure increased when the shunt assistant was in the vertical position, as specified. The valve has a low hydrodynamic resistance (0.53 mm mmHg ml-1 min-1). External programming proved to be easy and reliable. Strong magnetic fields from a 3 Tesla MR scanner were not able to change the programming of the valve.

Conclusion

The ProGAV shunt is an adjustable, low resistance valve that is able to limit posture-related over-drainage. Unlike other adjustable valves, the ProGAV cannot be accidentally re-adjusted by external magnetic field such as a 3T MR scanner.
Chiropractic manipulation in Adolescent Idiopathic Scoliosis: a pilot study
Authors: Rowe Dale E , Feise Ronald J , Crowther Edward R , Grod Jaroslaw P , Menke J Michael , Goldsmith Charles H , Stoline Michael R , Souza Thomas A , Kambach Brandon
Published: August 2006

Background

Adolescent idiopathic scoliosis (AIS) remains the most common deforming orthopedic condition in children. Increasingly, both adults and children are seeking complementary and alternative therapy, including chiropractic treatment, for a wide variety of health concerns. The scientific evidence supporting the use chiropractic intervention is inadequate. The purpose of this study was to conduct a pilot study and explore issues of safety, patient recruitment and compliance, treatment standardization, sham treatment refinement, inter-professional cooperation, quality assurance, and outcome measure selection.

Methods

Six patients participated in this 6-month study, 5 of whom were female. One female was braced. The mean age of these patients was 14 years, and the mean Cobb angle was 22.2 degrees. The study design was a randomized controlled clinical trial with two independent and blinded observers. Three patients were treated by standard medical care (observation or brace treatment), two were treated with standard medical care plus chiropractic manipulation, and one was treated with standard medical care plus sham manipulation. The primary outcome measure was Cobb, and the psychosocial measure was Scoliosis Quality of Life Index.

Results

Orthopedic surgeons and chiropractors were easily recruited and worked cooperatively throughout the trial. Patient recruitment and compliance was good. Chiropractic treatments were safely employed, and research protocols were successful.

Conclusion

Overall, our pilot study showed the viability for a larger randomized trial. This pilot confirms the strength of existing protocols with amendments for use in a full randomized controlled trial.

Trial registration

This trial has been assigned an international standard randomized controlled trial number by Current Controlled Trials, Ltd.http://www.controlled-trials.com/isrctn/. The number is ISRCTN41221647.
Radiation-induced leiomyosarcoma of the oropharynx
Authors: Pfeiffer Jens , Boedeker Carsten Christof , Ridder Gerd Jürgen , Maier Wolfgang , Kayser Gian
Published: August 2006

Leiomyosarcoma is a malignant mesenchymal tumor originating from smooth muscle cells, which most frequently develops in the myometrium and in the gastro-intestinal tract. Reviewing the international literature, radiation-induced sarcoma arise in 0.035 to 0.2 % of all irradiated patients. Especially in the head and neck region, radiation-induced leiomyosarcoma is an extremely rare lesion. The authors report a case of a radiation-induced leiomyosarcoma of the tonsillar region of the oropharynx in a 51-year-old male patient, who had undergone radiation therapy of this region 38 years before. The lesion was treated by radical surgery. Diagnostic steps, histological presentation and therapy are described in detail and the literature concerning radiation induced malignancies in general as well as radiation induced leiomyosarcoma in particular is reviewed. The highlights of this case are an extremely uncommon location and a rare pathological entity of radiation induced malignancies.
Bcl-2 over-expression fails to prevent age-related loss of calretinin positive neurons in the mouse dentate gyrus
Authors: Han Mingbo , Schottler Frank , Lei Debin , Dong Elizabeth Y , Bryan Alexander , Bao Jianxin
Published: August 2006

Background

Cognitive performance declines with increasing age. Possible cellular mechanisms underlying this age-related functional decline remain incompletely understood. Early studies attributed this functional decline to age-related neuronal loss. Subsequent studies using unbiased stereological techniques found little or no neuronal loss during aging. However, studies using specific cellular markers found age-related loss of specific neuronal types. To test whether there is age-related loss of specific neuronal populations in the hippocampus, and subsequently, whether over-expression of the B-cell lymphoma protein-2 (Bcl-2) in these neurons could delay possible age-related neuronal loss, we examined calretinin (CR) positive neurons in the mouse dentate gyrus during aging.

Result

In normal mice, there was an age-related loss of CR positive cells in the dentate gyrus. At the same region, there was no significant decrease of total numbers of neurons, which suggested that age-related loss of CR positive cells was due to the decrease of CR expression in these cells instead of cell death. In the transgenic mouse line over-expressing Bcl-2 in neurons, there was an age-related loss of CR positive cells. Interestingly, there was also an age-related neuronal loss in this transgenic mouse line.

Conclusion

These data suggest an age-related loss of CR positive neurons but not total neuronal loss in normal mice and this age-related neuronal change is not prevented by Bcl-2 over-expression.
HIV-1 coreceptor preference is distinct from target cell tropism: a dual-parameter nomenclature to define viral phenotypes
Authors: Goodenow Maureen M , Collman Ronald G
Published: August 2006

HIV-1 infection of cells is mediated by engagement between viral envelope glycoproteins (Env) and a receptor complex comprising CD4 and one of two chemokine receptors, CCR5 and CXCR4, expressed on the surface of target cells. Most CD4+-transformed T cell lines express only CXCR4, but primary lymphocytes and macrophages, the main cellular targets for infection in vivo, express both coreceptors. Cell- and viral strain-specific utilization of these coreceptor pathways, rather than coreceptor expression per se, regulates lymphocyte and macrophage entry and tropism. Virus use of coreceptor[s] (R5, X4, or R5 and X4) and its target cell tropism (lymphocytes, macrophages, and/or transformed T cell lines) are related but distinct characteristics of Envs. A comprehensive classification schema of HIV-1 Env phenotypes that addresses both tropism and coreceptor use is proposed. Defining Env phenotype based on both parameters is important in the development of entry inhibitors and vaccines, for understanding changes in Env that evolve over time in vivo, and for discerning differences among viral species that underlie aspects of pathogenesis and transmission. Recognizing how tropism is related to, yet differs from, coreceptor selectivity is critical for understanding the mechanisms by which these viral characteristics impact pathogenesis.
An investigation into the utility of the Stroke Aphasic Depression Questionnaire (SADQ) in care home settings
Authors: Sackley Catherine M , Hoppitt Thomas J , Cardoso Karina
Published: August 2006

Objective: To assess the utility of the Stroke Aphasia Depression Scale (SADQ) to identify emotional distress among individuals living in a care home setting.

Design: A prospective comparison of the SADQ and the depression subsection of the Hospital Anxiety and Depression Scale (HADS).

Setting: Care homes in Oxfordshire.

Participants: Eighty-two care home residents without major communication or cognitive problems.

Measures: Participants completed the HADS. The SADQ was completed on behalf of each resident by his or her principal carer.

Results: Spearman's rank correlation between the two measures was statistically significant (r=0.447, P B< 0.01). Receiver operator characteristics plots revealed an optimal cut-off point of 14 on the SADQ which gave sensitivity and specificity of 77% and 78% respectively.

Conclusion: The SADQ, an observational measure, can identify emotional distress in non-aphasic patients in a care home setting. It would be reasonable to use it with people with communication and cognitive problems who are unable to take part in conventional assessments.
Segmental stabilizing exercises and low back pain. What is the evidence? A systematic review of randomized controlled trials
Authors: Rackwitz Berid , de Bie Rob , Limm Heribert , von Garnier Katharina , Ewert Thomas , Stucki Gerold
Published: August 2006

Study design: A systematic review of randomized controlled trials.

Objectives: To evaluate the effectiveness of segmental stabilizing exercises for acute, subacute and chronic low back pain with regard to pain, recurrence of pain, disability and return to work.

Methods: MEDLINE, EMBASE, CINAHL, Cochrane Controlled Trials Register, PEDro and article reference lists were searched from 1988 onward. Randomized controlled trials with segmental stabilizing exercises for adult low back pain patients were included. Four comparisons were foreseen: (1) effectiveness of segmental stabilizing exercises versus treatment by general practitioner (GP); (2) effectiveness of segmental stabilizing exercises versus other physiotherapy treatment; (3) effectiveness of segmental stabilizing exercises combined with other physiotherapy treatment versus treatment by GP and (4) effectiveness of segmental stabilizing exercises combined with other physiotherapy treatment versus other physiotherapy treatment.

Results: Seven trials were included. For acute low back pain, segmental stabilizing exercises are equally effective in reducing short-term disability and pain and more effective in reducing long-term recurrence of low back pain than treatment by GP. For chronic low back pain, segmental stabilizing exercises are, in the short and long term, more effective than GP treatment and may be as effective as other physiotherapy treatments in reducing disability and pain. There is limited evidence that segmental stabilizing exercises additional to other physiotherapy treatment are equally effective for pain and more effective concerning disability than other physiotherapy treatments alone. There is no evidence concerning subacute low back pain.

Conclusion: For low back pain, segmental stabilizing exercises are more effective than treatment by GP but they are not more effective than other physiotherapy interventions.
Long-term effects of the intensification of the transition between inpatient neurological rehabilitation and home care of stroke patients
Authors: Gräsel E , Schmidt R , Biehler J , Schupp W
Published: August 2006

Objective: To investigate an intensified transition concept between neurological inpatient rehabilitation and home care for long-term effects on the care situation two and a half years after stroke patients' discharge.

Design: Controlled clinical trial allocating patients to intervention group (intensified transition on ward II) or control group (standard transition on ward I); patients were allocated to whichever ward had a vacancy. The last follow-up assessment was carried out on average 31 months after discharge.

Intervention: The intensified transition concept consisted of therapeutic weekend care, bedside teaching and structured information for relatives during the second phase of the rehabilitation.

Subjects: Seventy-one patients and their family carers were included, of which one case dropped out. Therefore 70 family carers - 35 individuals in each group - were available for assessment at long-term follow-up.

Data collection: Family carers were asked via telephone whether the patient was still alive and if so, where he or she is living - at home or in a nursing home.

Statistical methods: Binary logistic regression analysis with the care situation (home care versus institutionalized care or deceased) as dependent variable.

Results: Two and a half years after discharge (T3) in the intervention group significantly fewer patients were institutionalized (2 versus 5) or deceased (4 versus 11) (P = 0.010). Multivariate analysis showed that besides a higher functional life quality at discharge and lower patient's age, the participation in the intensified transition programme is the third significant predictor for home care at T3.

Conclusion: Effects of an intensified transition programme can persist over a long-term period. They can sustain home care by reducing institutionalization and mortality.
Toward an evidence-based toxicology
Authors: Hoffmann S , Hartung T
Published: August 2006

The increasing demands on toxicology of large-scale risk assessment programmes for chemicals and emerging or expanding areas of chemical use suggest it is timely to review the toxicological toolbox. Like in clinical medicine, where an evidence-based medicine (EBM) is critically reviewing traditional approaches, toxicology has the opportunity to reshape and enlarge its methodology and approaches on the basis of compounded scientific knowledge. Such revision would have to be based on structured reviews of current practice, ie, assessment of test performance characteristics, mechanistic understanding, extended quality assurance, formal validation and the use of integrated testing strategies. This form of revision could optimize the balance between safety, costs and animal welfare, explicitly stating and, where possible, quantifying uncertainties. After a self-critical reassessment of current practices and evaluation of the thus generated information, such an evidence-based toxicology (EBT) promises to make better use of resources and to increase the quality of results, facilitating their interpretation. It shall open up hazard and also risk assessments to new technologies, flexibly accommodating current and future mechanistic understanding. An EBT will be better prepared to answer the continuously growing safety demands of modern societies.
Lower expression of p14ARF and p16INK4a correlates with higher DNMT3B expression in human oesophageal squamous cell carcinomas
Authors: de Almeida Simão Tatiana , De Bonis Almeida Simões Gabriela Loureiro , Ribeiro Fabiana Siqueira , de Paula Cidade Daniela Anhel , Andreollo Nelson Adami , Lopes Luiz Roberto , Macedo Jacyara Maria Brito , Acatauassu Rodolfo , Teixeira Ana Maria Rossini , Felzenszwalb Israel , Pinto Luis Felipe Ribeiro , Albano Rodolpho Mattos
Published: August 2006

Oesophageal squamous cell carcinoma (ESCC) is one of the most common malignancies and is the sixth cause of cancer-related death in the world. Inactivation of cell-cycle regulating genes, such as p14ARF and p16INK4a, and cell adhesion genes, such as E-cadherin, is common in cancer, and results from genetic and/or epigenetic alterations. Therefore, we have analysed the mRNA expression of p14ARF, p16INK4a and E-cadherin in 17 matched ESCC and normal mucosal samples obtained from Brazilian patients by semi-quantitative RT-PCR. The expression of p14ARF and p16INK4a was absent or reduced in several ESCC samples. Hypermethylation of CpG islands, caused by the action of DNA methyltransferases (DNMTs), is a major form of epigenetic inactivation of the p14ARF and p16INK4a genes in tumours. Hence, we also investigated the mRNA expression of the human DNA methyltransferases in normal oesophageal mucosa and in the tumour matched samples. All DNMTs were constitutively expressed in the normal oesophageal mucosa but a significantly higher expression of DNMT3B was observed in the tumours. Data analysis by the Spearman rank test showed that the expression of DNMT3B was inversely correlated with that of p14ARF and p16INK4a. Our results suggest that DNMT3B over-expression may be involved in the suppression or lower expression of p14ARF and p16INK4a observed in ESCC.
An Engineering Approach for Design and Analysis of Metallic Pipe Joints Under Torsion by the Finite Element Method
Authors: Hosseinzadeh R , Cheraghi N , Taheri F
Published: August 2006

Design and stress analysis of pipe joints are still matters of controversy with respect to a unified design approach, despite the fact that many exact and finite element solutions have been presented in the literature. Owing to the complicated and lengthy nature of most exact solutions, development of an applied method for optimized design and stress analysis of a strong and low-cost joint remains a pressing issue. In this work, a simple method was developed for assessing the behaviour of adhesively bonded tubular joints under torsion, based on a parametric study conducted by ABAQUS finite element software. Many case studies of typical metallic joints under torsion were considered for examining the interactions among the main parameters governing the joint performance (i.e. adhesive thickness, pipe and coupling thickness/diameter, joint length, and material properties). Finally, a prototypical joint was designed by using the developed design curves, and the stress distributions were verified by the same software.
An Analysis of Ride Coupling in Automobile Suspensions
Authors: Odhams A M C , Cebon D
Published: August 2006

The tuning of a pitch-plane model of a passenger car with a ‘coupled’ suspension system was investigated and compared to that of a conventional suspension system. Direct comparison of stiffness matrices for the two models was used as well as modal analysis and frequency domain analysis, to gain insight into the optimal pitch-bounce tuning. Performance was measured in terms of body acceleration, dynamic tyre force, and suspension working space. Optimum tuning of the coupled system was found to be at lower pitch stiffness, but greater pitch damping than that of a popular saloon car. Uncorrelated inputs to the model were found to give tuning suitable for a realistic range of road speeds from 5 to 25 m/s. The Olley suspension tuning criterion was found to represent an optimal conventional suspension stiffness tuning for dynamic tyre force minimization, but not for driver chest acceleration minimization.
Kriging Optimal Design of an Intake System with Meta-Heuristic Methods for Reducing Noise
Authors: Ryu Je-Seon , Sim Hyoun-Jin , Chin Chung-Un , Park Young-Sun , Cha Kyung-Joon , Oh Jae-Eung
Published: August 2006

Recently, government regulations and public concern have increased interest in noise pollution levels. Therefore, many researchers have studied to reduce this noise in the field of automotive engineering. The current paper proposes an optimal design scheme to reduce the noise of the intake system by adapting Kriging with two meta-heuristic techniques. This was achieved by using performance prediction software (developed by one of the present authors and his co-workers) as a measuring tool for the performance of the intake system. The length and radius of each component of the current intake system were then selected as input variables and the L18 table of orthogonal arrays was adapted as a space-filling design. With these simulated data, a correlation parameter can be estimated in Kriging by solving the non-linear problem with a genetic algorithm to find an optimal level for the intake system by optimizing Kriging estimated through simulated annealing. This optimal design scheme gives significant results and is a preferable way to analyse the intake system. Therefore, an optimal design for the intake system is proposed for reducing the noise of its system.
Modelling a Twin Tube Cavitating Shock Absorber
Authors: Alonso M , Comas Á
Published: August 2006

An analytical method to quantify the damping force of a twin tube shock absorber is proposed. Fluid and chambers compressibility effects and fluid cavitation are included. A comparison of a calculated damping force against the ideal damping force (assuming that non-cavitation occurs) is presented.
Modelling of Unsteady Gas-Dynamic Flow in a Pipe and at Its Exit using CFD
Authors: Thornhill D , Li Hongyan , Fleck R , Cuningham G
Published: August 2006

Traditionally the simulation of the thermodynamic aspects of the internal combustion engine has been undertaken using one-dimensional gas-dynamic models to represent the intake and exhaust systems. Computational fluid dynamics (CFD) analysis of engines has been restricted to modelling of in-cylinder flow structures. With the increasing accessibility of CFD software it is now worth considering its use for complete gas-dynamic engine simulation. This paper appraises the accuracy of various CFD models in comparison with a one-dimensional gas-dynamic simulation. All of the models are compared to experimental data acquired on an apparatus that generates a single gas-dynamic pressure wave. The progress of the wave along a constant area pipe and its subsequent reflection from the open pipe end are recorded with a number of high-speed pressure transducers.

It was found that there was little to choose between the accuracy of the one-dimensional model and the best CFD model. The CFD model did not require experimentally derived loss coefficients to represent accurately the open pipe end; however, it took several hundred times longer to complete its analysis. The best congruency between the CFD models and the experimental data was achieved using the RNG k-∊ turbulence model. The open end of the pipe was most effectively represented by surrounding it with a relatively small volume of cells connected to the rest of the environment using a pressure boundary.
Strategies and Calculation Methods for Automotive Powertrain Motion Control under Quasi-Static Loads
Authors: Shangguan Wen-Bin , Hou Zhichao
Published: August 2006

The mount in an automotive powertrain mounting system (PMS) is modelled as three-dimensional springs in its local coordinate system (LCS). The relation of the force versus the displacement of each spring is usually non-linear and is simplified as piecewise linear at five ranges in the present paper. The equation for solving displacements of the powertrain centre of gravity is presented, and an iterative algorithm is developed to obtain the displacements. The methods for estimating the displacements and the reaction forces of a mount are also proposed. The widely used strategies for the powertrain motion control under static or quasi-static loads are suggested. The calculation method is validated in designing a PMS with four mounts. The present paper adds significantly to other publications on this subject because it develops a calculation method for the design of the powertrain motion control under quasi-static loads.
Eco-Diesel Engine Fuelled with Rapeseed Oil Methyl Ester and Ethanol. Part 3: Combustion Processes
Authors: Kowalewicz A
Published: August 2006

In Part 1 of the paper efficiency and emissions of the engine fuelled with rape oil methyl ester (RME) and ethanol were presented and discussed. In the second part of the paper a comparison of emissions and brake fuel conversion efficiency of the engine for two base fuels, diesel fuel and rape oil ethyl ester, was carried out. In this paper, Part 3, combustion processes are investigated. Experiments were carried out on the same single-cylinder direct injection compression ignition engine as in Part 1. In the course of the experiments the pressure-time history of the engine cylinder and instantaneous parameters of injection of the RME fuel were measured and used to calculate the rate of heat release and the fraction of fuel burnt versus crank angle, which showed that the higher the energy fraction of ethanol in the total fuel, the longer the ignition delay but the shorter the total time of combustion. It was found that shorter combustion results in higher efficiency.
Pedestrian Risk from Cars and Sport Utility Vehicles - A Comparative Analytical Study
Authors: Simms C K , Wood D P
Published: August 2006

Analysis of real-world crash data from the USA shows that 11.5 per cent of pedestrians struck by large sport utility vehicles (SUVs) are killed, compared with 4.5 per cent of pedestrians struck by passenger cars. The design of the vehicle front-end structure has a substantial influence on injury outcome when pedestrians are struck by vehicles. In the context of the rising population of SUVs, it is important to determine the causes of their increased hazard to pedestrians. In this paper, validated multi-body models are used to show that the shape of SUVs results in higher pedestrian injuries to the mid-body regions compared to passenger cars. Analysis shows that the mass difference between cars and SUVs is not significant for pedestrian injury causation and it is shown that an important effect of the higher front profile of SUVs is that the pedestrian is struck more centrally with respect to the body's centre of gravity, increasing the momentum transfer in the primary impact. A further important effect of the higher bonnet leading edge is that there is a direct impact to the mid-body region, which explains the significant abdomen and other internal injuries reported from real-world SUV/pedestrian impacts. By comparison, head injuries sustained from primary vehicle contact are shown to be similar or slightly lower for SUV/pedestrian impacts compared to car/pedestrian impacts. However, real-world evidence and the current models suggest that the secondary impact with the ground is more severe in SUV/pedestrian impacts compared to car/pedestrian impacts. Overall, these results show that the empirical finding that SUVs are more hazardous for pedestrians than passenger cars is primarily a function of the high bumper and bonnet for such vehicles.
Importance of Head Diameter, Clearance, and Cup Wall Thickness in Elastohydrodynamic Lubrication Analysis of Metal-On-Metal Hip Resurfacing Prostheses
Authors: Liu Feng , Jin Zhongmin , Roberts P , Grigoris P
Published: August 2006

The main design features of metal-on-metal (MOM) hip resurfacing prostheses in promoting elastohydrodynamic lubrication were investigated in the present study, including the femoral head diameter, the clearance, and the cup wall thickness. Simplified conceptual models were developed, based on equivalent uniform wall thicknesses for both the cup and the head as well as the support materials representing bone and cement, and subsequently used for elastohydrodynamic lubrication analysis. Both typical first- and second-generation MOM hip resurfacing prostheses with different clearances and cup wall thicknesses were considered with a fixed large bearing diameter of 50 mm, as well as a 28 mm diameter MOM total hip replacement bearing for the purpose of comparison. The importance of the head diameter and the clearance in promoting elastohydrodynamic lubrication was confirmed. Furthermore, it was also predicted that a relatively thin acetabular cup in the more recently introduced second-generation MOM hip resurfacing prostheses would be capable of improving elastohydrodynamic lubrication even further.
The Effects of Proteins on the Friction and Lubrication of Artificial Joints
Authors: Scholes S C , Unsworth A
Published: August 2006

The tribological testing of artificial hip and knee joints in the laboratory has been ongoing for several decades. This work has been carried out in an attempt to simulate the loading and motion conditions applied in vivo and, therefore, the potential for the success of the joint. However, several different lubricants have been used in these tests. The work documented in this paper compares results obtained using different lubricants and makes suggestions for future work. Hip joints and knee joints of different material combinations were tested in a friction simulator to determine their friction and lubrication properties. Both carboxymethyl cellulose (CMC) fluids and bovine serum (with CMC fluids added) were used as the lubricants. These were prepared to various viscosities to produce the Stribeck plots. Human synovial fluid, of just one viscosity, was used as the lubricant with some of the joints to give a true comparison with physiological lubricants. The results showed that, in most cases, the lubricant had a significant effect on the friction developed between the joint surfaces. This is thought to be due to the proteins that are present within the bovine serum adsorbing to the bearing surfaces, creating ‘solid-like’ films which rub together, protecting the surfaces from solid-to-solid contact. This would be beneficial in terms of wear but can either increase or decrease the friction between the contacting surfaces. It is important to simulate the conditions in vivo as closely as possible when testing these joints to try to obtain a better comparison between the joints and to simulate more accurately the way that these joints will operate in the body. In an attempt to simulate synovial fluid, bovine serum seems to be the most popular lubricant used at present. It would be beneficial, however, to develop a new synthetic lubricant that more closely matches synovial fluid. This would allow us to predict more accurately how these joints would operate long term in vivo.
A Pilot Study in the Application of Texture Relief for Digitally Designed Facial Prostheses
Authors: Eggbeer D , Evans P L , Bibb R
Published: August 2006

This pilot research aims to identify and assess suitable technologies that may be used to capture, create, and produce fine textures and wrinkles that may be incorporated into computer aided prosthesis design and production techniques. A range of suitable technologies is identified and two methods that may be used in different prosthetic rehabilitation situations are assessed: the creation of three-dimensional relief in a computer aided design environment and the capture of facial anatomy and texture using fringe-projection surface scanning. Patterns were produced using the suitable rapid prototyping processes identified, and these were assessed by a qualified and experienced prosthetist. The suitability of the technologies is commented upon, limitations discussed, and future directions identified.
Winding Control Using Pseudo-Derivative Feedback
Authors: White A , Iwashita T , Strothmeyer H , Buaka L. D. , Sinclair R
Published: August 2006

This work examines the winding of film from one free reel to a driven reel using both a pseudo-derivative feedback (PDF) and a proportional-integral-derivative (PID)-controlled servomotor. Measurements are compared with a theoretical model simulated with Simulink®. In this work, only the velocity of the film was controlled after measurement with an optical encoder; tension in the film was not controlled. The measurements and control were executed on a personal computer using LabVIEW®. Overall both controllers could cope with the range of full and empty reels for a demand velocity step of 1 m/s but the PDF controller could cope with a demand for 2 m/s. Rise times of less than 500 ms were obtained for both controllers with the best PID controller faster at around 130 ms. The motor current required for the PDF controller was less than that for the PID system. Tension forces were, as predicted, higher with PID control; therefore the overall steady state average error was zero for both controllers. The results show that the rise time differences to achieve steady state in the case when opposite spools were full were less for the PID controller.
Friction Compensation of an Actively Restrained Clutch for Path Tracking
Authors: Lacraru L. M. , Bouazza-Marouf K
Published: August 2006

Friction compensation of an electromechanical friction clutch mechanism capable of restraining motion so that various predefined paths can be followed is investigated in this paper. The clutch mechanism is driven by an external source of energy, and a computer-controlled system is used to produce frictional resistance so that a desired motion can be achieved. Unknown stick-slip within the clutch is a critical characteristic of the system, which has to be overcome. Three different controllers are investigated in order to avoid stick-slip at low motion rates. A proportional-derivative controller, a sliding-mode controller, and a computed-torque controller, have been implemented and their performances compared using simulation and experimental analyses. The results demonstrate the effectiveness of the sliding-mode controller and the potential of a computed-torque controller for the motion control in a system with dry friction at low velocities.
Reduced-Order Thermodynamic Models for Servo-Pneumatic Actuator Chambers
Authors: Carneiro J Falcão , de Almeida F Gomes
Published: August 2006

This paper discusses thermodynamic models of air inside pneumatic actuator chambers. In servo-pneumatics common practice, these models are simplified by neglecting the temperature dynamics. Classical models in the literature assume the temperature inside the pneumatic chamber either to be constant or to follow a polytropic law. Furthermore, the mixing process of air entering the chamber and heat transfer between air and cylinder walls is often neglected or only implicitly taken into account.

This work evaluates the impact of these simplifications and order reductions in the prediction of pressure inside the actuator chamber. Classical models are compared with several others not only taking into account the mixing process but also explicitly including the heat transfer between air and cylinder walls. Simulation studies show that the reduced-order models proposed in this paper can lead to a mean square error in pressure prediction of only 10 per cent of that obtained using classical models.
Influence of Chemical and Physical Contaminants on the Antiwear Performance of Model Automotive Engine Oil
Authors: Masuko M , Suzuki A , Ueno T
Published: August 2006

The antiwear performance of simulated used-engine-oil that contained a chemical contaminant (degraded zinc dialkyldithiophosphate (ZnDTP)) was studied with and without physical contamination (carbon black) using a four-ball tribometer. By reacting with cumene hydroperoxide, sec-C6-ZnDTP was degraded and produced many compounds containing both phosphorous and sulphur. The simulated used-oils were found to promote wear. This wear was considered to be due to corrosive wear by the excess reaction of surfaces with the sulphur contained in the degraded compounds. Carbon black was used to model carbon soot, which is another key substance of degraded engine oils, especially in diesel engines, to study the synergism between chemical contamination (ZnDTP degradation) and physical contamination (carbon soot contamination). Carbon black increased wear irrespective of the level of ZnDTP degradation, and the acceleration was much greater in the degraded oils. The wear acceleration by carbon black was observed even when the antiwear film from ZnDTP was already present on the surface. It was suggested that the wear acceleration by carbon black was due to abrasion.
Determination of Roll Motion for a Floating Body in Regular Waves
Authors: Das S K , Sahoo P K , Das S N
Published: August 2006

This paper deals with the mathematical modelling of the roll motion of a floating body in regular waves in beam seas for non-restrained conditions. The hydrodynamic forces are computed with the application of strip theory, and frequency dependent sectional added mass moment of inertia and damping are integrated over the length of the body by using the Frank close fit method. The governing equation that arises after balancing the hydrodynamic and exciting forces is reduced to non-dimensional form prior to converting it into the frequency domain by applying the Laplace transform technique. Numerical experiments have been carried out for a vessel of 19 190 t displacement under the action of a small amplitude sinusoidal wave of 11.2 s periodicity to obtain the roll response. This has been done in order to check the roll response computed numerically by developing a numerical model, SHIPMOT-R, where the Runge-Kutta-Gill method is adopted. A good agreement has been achieved between the time histories of roll motions computed numerically and derived analytically for zero and nonzero forward speeds. It is observed that the roll amplitude increases with the increase of vessel speed. This modelling technique would be very useful for ascertaining a vessel's safety requirements in the early stages of design.
Season of birth and childhood intelligence: Findings from the Aberdeen Children of the 1950s cohort study
Authors: Lawlor Debbie A. , Clark Heather , Ronalds Georgina , Leon David A.
Published: August 2006

Background. In this study, 2 main hypotheses have been put forward to explain the variation in childhood intelligence or school performance by season of birth. In the first hypothesis, it is suggested that it is due to school policy concerning school entry, whereas the second suggests that a seasonally patterned exposure such as temperature, maternal nutrition, or infection during critical periods of brain development have a lasting effect on intelligence.

Aims. To determine whether childhood performance on tests of different domains of intelligence is patterned by season of birth and to examine possible mechanisms for any associations.

Sample. 12,150 individuals born in Aberdeen, Scotland between 1950 and 1956.

Methods. Birth cohort study in which the variation in different domains of childhood intelligence measured at ages 7, 9, and 11 by season of birth were examined.

Results. Reading ability at age 9 and arithmetic ability at age 11 varied by season of birth, with lowest scores among those born in autumn or early winter (September–December) and highest scores among those born in later winter or spring (February–April); p = .002 for joint sine‐cosine functions for reading ability at age 9 and p = .05 for sine‐cosine function for arithmetic ability at age 11. The child's perception and understanding of pictorial differences at age 7, verbal reasoning at 11, and English language ability at 11 did not vary by season of birth. Age at starting primary school and age relative to class peers were both associated with the different measurements of childhood intelligence and both attenuated the association between month of birth and reading ability at age 9 and arithmetic ability at age 11 towards the null. Both adjusted and unadjusted differences in reading ability at age 9 and arithmetic ability at age 11 between those born from September to December compared with other times of the year were less than 0.1 of a standard deviation of the test scores. Ambient temperature around the time of conception, during gestation, and around the time of birth did not affect intelligence.

Conclusion. Any variation in mean childhood intelligence by season of birth is weak and largely explained by age at school entry and age relative to class peers.
Teachers' and pupils' definitions of bullying
Authors: Naylor Paul , Cowie Helen , Cossin Fabienne , de Bettencourt Rita , Lemme Francesca
Published: August 2006

Background. Comparison of teachers' and pupils' definitions of bullying is important for considering the implications for reports of its incidence in schools, for the study of developmental trends in children's and adolescents' perceptions of the phenomenon and for evaluating the effectiveness of interventions designed to combat bullying.

Aims. To investigate the effects of gender, teacher/pupil status and, for pupils, bullied/non‐bullied (target/non‐target) status and age on the definition of bullying.

Samples. Teachers (N = 225: 158 women, 67 men) and pupils (N = 1,820: 466 boys, 460 girls were 11–12 years old, year 7, and 415 boys, 479 girls were 13–14 years, year 9) in 51 UK secondary schools participated in a questionnaire survey. A total of 557 of the pupils (117 girls and 117 boys aged 11–12 years, and 197 girls and 126 boys aged 13–14 years) reported that they had been bullied at some time in their present school.

Methods. Written questionnaire responses to the question, ‘Say what you think bullying is’ have been content analysed to derive two sets of categories, one of bullying behaviour and the other of effects of bullying on the target.

Results. Regarding both bullying behaviour and the effects of bullying on the target, teachers – by comparison with pupils – have been found to express more comprehensive ideas in their definitions. Specifically, pupils compared with teachers are more likely to restrict their definitions to direct bullying (verbal and/or physical abuse) and are less likely to refer to social exclusion, a power imbalance in the bully's favour and the bully's intention to cause the target hurt or harm and to feel threatened. Analysis of definitions on the bases of sex, pupil age and target/non‐target status show that: targets are more likely than non‐targets are to refer to the bully's physically and verbally abusive behaviour, and for Year 7 compared with Year 9 pupils, to suggest that bullies socially exclude targets; girls are more likely than boys are to mention verbal abuse and the effects on the target of ‘Feels hurt/harm’, but boys are more likely than girls are to construe bullying as involving repetition; older pupils are more likely than younger ones are to refer to a power imbalance in the bully's favour but, for bully targets, younger ones compared with older ones are more likely to invoke the idea of social exclusion in their definitions.

Conclusions. The most important implication of the findings of this study that there are important differences between teachers' and pupils' definitions of bullying is that teachers need to listen carefully to what pupils have to say about bullying and work with and help them to develop their conceptions of the phenomenon. Some teachers, too, need to develop their conceptions of bullying.