bluuebunny/crossref_metadata_2025 huggingface dataset:
The Biophysical Effects of a Single Impact Load on Human and Bovine Articular Cartilage
Authors: Jeffrey J E , Aspden R M
Published: August 2006

Impact injury to a joint is a known risk factor for the subsequent development of secondary osteoarthritis. An in vitro model, employing a drop-tower loading machine, was used to examine the effect of an impact load on isolated articular cartilage explants from human and bovine femoral heads. Two different types of impact experiment were performed. In the first, 4 mm diameter explants were loaded using a plane-ended impactor. In the second, a modified impactor was developed that had a central 4 mm diameter plane-ended indentor which was used to load the centre of 8 mm diameter explants. This enabled the unloaded outer ring of each explant to be compared with the loaded central core. The modulus values measured using the impactor were found to be higher, compared with the indentor in both species. Scanning electron microscopy showed that cartilage surrounding the loaded central region of the 8 mm explants protected the indented tissue, and these explants showed less damage than the 4 mm samples that were fully impacted. In addition, human cartilage was found to be less damaged than bovine, possibly as a consequence of the different structure as well as of a greater thickness. Both the source of the tissue and the nature of the impact affected the type of damage observed.
Three-Dimensional Finite Element Stress and Strain Analysis of a Transfemoral Osseointegration Implant
Authors: Xu Wei , Xu Dong Hao , Crocombe A D
Published: August 2006

The percutaneous transfemoral osseointegration implant is an alternative technique for direct prosthetic limb attachment. In order to investigate the stress and strain in the trans-femoral osseointegration implant system, finite element (FE) analyses were carried out using three-dimensional femur-implant models and the commercial FE software ABAQUS. The three-dimensional femoral model was reconstructed from presurgery CT scans of an above-knee amputee. The implant was then inserted into the femoral model using Boolean operations in CAD software. Under a typical walking load, stress and strain from the femur-implant FE model were investigated. Stress concentrations were found near to the distal and proximal regions of the femur. To study the effect of different contact ratios between femur and implant, FE analyses were carried out using different implant diameters. The results showed that there were local stress variations near the contact discontinuity areas. A comparison was also made between the results of this study and a previous study using axisymmetric FE models. The results of the two studies revealed different stress levels, but good correlation was found in the overall stress distribution.
New Construction of an Electro-Conjugate Fluid-Jet-Driven Micromotor with an Inner Diameter of 2 mm
Authors: Yokota S , Edamura K
Published: August 2006

Electro-conjugate fluid (hereafter abbreviated as ECF) is a kind of dielectric fluid that produces a powerful jet flow (ECF jet) between rod-type electrodes in an applied non-uniform static electric field. By using the ECF jet, a new type of micromotor with a simple structure and light weight can be realized. Until now, some types of ECF micromotors have been developed with a 3 mm inner diameter. In this study, a micromotor is fabricated with a 2 mm inner diameter in order to improve the output power density, using the ECF jet. The micromotor was first designed and fabricated; then, the performance of the motor was measured. The experimental results confirm that the micromotor developed here has a higher power density than the micromotors previously developed with 3 mm inner diameter.
Hybrid Learning Control Schemes with Acceleration Feedback of a Flexible Manipulator System
Authors: Tokhi M O , Zain M Z Md
Published: August 2006

This paper presents investigations into developing a hybrid iterative learning control scheme with acceleration feedback. An experimental flexible manipulator rig and corresponding simulation environment are used to demonstrate the effectiveness of the proposed control strategy. A collocated proportional-derivative controller utilizing hub-angle and hub-velocity feedback is developed for control of rigid-body motion of the system. This is then extended to incorporate iterative learning control with acceleration feedback and genetic algorithms for optimization of the learning parameters for control of vibration (flexible motion) of the system. The system performance with the controllers is presented and analysed in the time and frequency domains. The performance of the hybrid learning control scheme without and with acceleration feedback is assessed in terms of input tracking and level of vibration reduction at resonance modes and robustness to variation in payload.
Storage Device Sizing for a Hybrid Railway Traction System by Means of Bicausal Bond Graphs
Authors: Gandanegara G , Roboam X , Sareni B
Published: August 2006

In this paper, the application of bicausal bond graphs for system design in electrical engineering is emphasized. In particular, it is shown how this approach is very useful for model inversion and parameter dimensioning. To illustrate these issues, a hybrid railway traction device is considered as a case study. The synthesis of a storage device (a supercapacitor) included in this system is then discussed.
Direct Self-Tuning Model-Following Control with Integral Action for a Variable-Frequency Oil-Cooling Process
Authors: Tsai Ching-Chih , Wang Tai-Yu , Lin Shui-Chun , Teng Fei-Jen
Published: August 2006

This paper presents a direct self-tuning model-following control with integral action for a variable-frequency oil-cooling process, suitable for cooling down high-speed machine tools. The oil-cooling process is experimentally modelled as a first-order system with a given time-delay Based on this model, a direct self-tuning model-following control with integral action is proposed for achieving set-point tracking and disturbance rejection. A real-time adaptive predictive control algorithm is then presented and implemented utilizing a standalone digital signal processor (DSP). In comparison with the control method of Tsai and Huang, the proposed method provides a more practical and less computationally intensive approach for achieving the desired high-precision set-point tracking and disturbance rejection. Experimental results show that the proposed control method is capable of giving a satisfactory set-point tracking performance under set-point changes, fixed loads, and load changes.
The Modelling, Prediction, and Experimental Evaluation of Gear Pump Meshing Pressures with Particular Reference to Aero-Engine Fuel Pumps
Authors: Eaton M , Keogh P S , Edge K. A.
Published: August 2006

This paper presents the development of a model for the evaluation of pressure transients occurring within an involute tooth form twin-pinion gear pump and addresses, in particular, the influence of cavitation. The latter can cause erosion, limiting the life of such pumps, and liberate hard particles, leading to secondary damage elsewhere. The model considers the inter-tooth volumes that are formed at the roots of the driver and driven gears and utilizes the continuity equations by considering compressible flow into and out of these volumes. Cavitation arising from insufficient flow into the expanding inter-tooth volumes is taken into account. The continuity equations are expressed in terms of fluid density rather than pressure. Hence correct solutions are ensured even during cavitating conditions, when the minimum void pressure is fixed at the appropriate vapour pressure. The effectiveness of the model is assessed through gear pump meshing pressure measurement and flow visualization. The significant influence of inlet pressure ripple on low-pressure predictions is also investigated.
Contouring Error Control of Machine Tool Drives with Backlash Compensation
Authors: ElBeheiry E. M.
Published: August 2006

This article presents ideas for contour error control of machine tools. A demonstration of these ideas is performed on a biaxial drive system exhibiting linear and circular contouring. A new independent contour error control (ICEC) strategy, which utilizes the equations of the well-known cross-coupling controller, is shown to diminish a linear contour error without using any cross-feeding signals between the driving axes. For circular contouring, new exact equations for contour error calculations are presented. These exact equations may lead to some significant control strategies that can be based on the cross-coupling control (CCC) concept. One new CCC strategy, based on one of these exact contour error equations, is shown to be very promising for circular contouring. Finally, the proposed strategies have been further developed for either independent or cross-coupling backlash compensation. These backlash compensation schemes may save complications of having special means for backlash control if CCC systems are intended for implementation.
State Observation for Elastoplastic Friction Models in Positioning Systems by Utilizing Leunberger Observers
Authors: Temeltas H , Aktas G
Published: August 2006

In this study, state observation in positioning systems is discussed. A dynamical friction model, also called an elastoplastic model, describing basic friction phenomena such as stick-slip dynamics, presiding motion, the Stribeck effect, etc., is included in the positioning system model. A Luenberger-type state observer is presented and developed for motion control systems with the non-linear elastoplastic friction model in order to overcome difficulties in measuring internal states physically. Since the parameters of the elastoplastic friction model are required in the experimental studies, a combined parameter identification method is also outlined in three different levels. Simulation and experimental results are presented to illustrate benefits of the method by observing both velocity and friction states. The proposed method is tested successfully on an electromechanical positioning system.
Robust Stability of Uncertain Linear Systems with Time-Varying Delay and Non-Linear Perturbations
Authors: Qiu Jiqing , Zhang Jinhui , Shi Peng
Published: August 2006

In this paper, the problem of robust stability for uncertain linear systems with time-varying delay and non-linear perturbations is investigated. The systems possess both nonlinear perturbations and norm-bounded uncertainties. Based on the Lyapunov-Krasovskii functional approach and S procedure, a new delay-dependent stability criterion is presented, which is in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness of the developed techniques.
Virtual-Design-Model-Based Pressure-Tracking Control of High-Dynamic Pneumatic Valves Using a Sliding Mode Controller Combined with a Proportional-Integral-Derivative Scheme
Authors: Cho S. H. , Fiedler M , Rüdiger F , Helduser S
Published: August 2006

This paper deals with the issue of pneumatic pressure-tracking control based on a virtual design model of high-dynamic valves. As a fundamental step prior to controller design, a virtual valve model is developed by defining the required parameters through analysing geometrical and material data. For validation of the virtual model, the open-loop performances of subsystems are compared with experimental results. A sliding-mode controller combining a proportional-integral-derivative scheme is developed for compensation of inherent non-linearities and thus a significant reduction in tracking error is achieved for pressure-tracking control applications.
A Linear-Programming-Based Sliding-Mode Control Design for Stabilization of a Double-Inverted Pendulum
Authors: Yazici A , Karamancioglu A
Published: August 2006

A linear programming approach for computation of sliding-mode control inputs is proposed. The method is applied to a double-inverted pendulum system and it takes input and approaching rate constraints into account. The derivation procedure reveals that it is generalizable to a large class of dynamic systems and can take a more general set of constraints into account. The approach preserves the robustness property of the sliding-mode control and enriches it by adding the features of the linear programming. The main feature incorporated into the sliding-mode control is the optimal update of the control inputs under a set of linear constraints. The constraints are specified to meet the sliding-mode conditions and to improve its undesired chattering behaviour.
Reliability Evaluation of Fault Tolerant Control with a Semi-Markov Fault Detection and Isolation Model
Authors: Li Hongbin , Zhao Qing
Published: August 2006

In this paper, a stochastic modelling method is used to study the reliability evaluation problem of fault-tolerant control systems (FTCSs). The faults in the system are described by a Markov chain, while the fault detection and isolation (FDI) and system operation for reliability evaluation are described by two semi-Markov chains. The semi-Markov description of FDI removes the restrictive memoryless assumption in Markov models and provides a general model for cyclic FDI schemes. Furthermore, a reliability index and evaluation method are presented for FTCSs. This index reflects the control performance and hard deadline and can be used as a quantitative reliability measure for FTCSs.
Anomaly Detection in Thermal Pulse Combustors Using Symbolic Time Series Analysis
Authors: Gupta S , Ray A , Mukhopadhyay A
Published: August 2006

This paper presents symbolic time series analysis of observable process variables for anomaly detection in thermal pulse combustors. The anomaly detection method has been tested on the time series data of pressure oscillations, generated from a non-linear dynamic model of a generic thermal pulse combustor. Results are presented to exemplify early detection of combustion instability due to reduction of friction coefficient in the tailpipe, which eventually leads to flame extinction.
Contaminants in Used Oils and Their Problems
Authors: Sasaki A
Published: August 2006

Contaminants in hydraulic and lubricating oils are harmful to lubrication. Therefore, contamination control of hydraulic and lubricating oils has been implemented in many factories and oil cleanliness standards of hydraulic and lubricating oils have been established as criteria for oil contamination control. There are two types of oil cleanliness standards: one is based on particle count and the other on gravimetric analysis. NAS 1638, ISO 4406, SAE AS4059, and JISB9930 belong to the former and ASTM D4898 and JISB9931 to the latter. The par tide count defines oil cleanliness by counting the number of particulate contaminants in the certain size ranges, and the gravimetric analysis shows the weight of contaminants remaining, on a membrane filter disc after a certain quantity of oil was filtered under vacuum, the oil was washed out, and the membrane filter disc was completely dried. Recently, there is a ten dency that particle count dominates the technology to judge oil cleanliness. Of course, it is important to quantify the number of particulate contaminants in oils. However, all particles are not contaminants, as particles like graphite and MoS2, which are countable by particle count, are good additives for lubricants. Therefore, it is very important for us not only to judge oil cleanliness by the particle count but also to know without prejudice what they are. This article discusses some methods to separate contaminants, what contaminants are, and how much they are.
Influence of Solid Contaminants on the Fatigue Life of Lubricated Machine Elements
Authors: Ville F , Coulon S , Lubrecht A. A.
Published: August 2006

Solid contamination of lubricants is one of the main causes of premature rolling contact fatigue of machine elements (e.g. rolling element bearings in automotive gearboxes). Understanding the indentation process (creation of surface defect by debris passing through the contact) and the surface damage initiation allows the prediction of the induced risk. This article summarizes the work of the authors and proposes a risk prediction on the basis of operating conditions and dent geometry.
Abrasive Wear of Rolling Bearings by Lubricant Borne Particles
Authors: Nilsson R , Dwyer-Joyce R. S. , Olofsson U
Published: August 2006

Damage caused by lubricant borne particles in rolling/sliding contacts can severely reduce the operational life of machine elements such as cam mechanisms, roller bearings, gears, and pumps. Lubricant supplies frequently contain such contaminating particles, either generated from within the machinery itself or entrained from the surroundings. The particle can be entrained into a lubricated contact and damage the bearing surfaces. Many such individual abrasive actions can lead to significant change in the surface profile of the rolling elements.

In this work, a series of experiments has been carried out to investigate the mechanism of this surface damage and abrasion process when the contaminating particles are small and hard. The tests show, how particles are entrained into the contacts, the form of the scratches they produce, and the resulting surface profile changes. On the basis of these observations, a model of the abrasive wear process has been developed. The prediction of abrasive wear compares qualitatively well with observed form change on the bearing surface.
Soot Wear in Diesel Engines
Authors: Yamaguchi E. S. , Untermann M , Roby S. H. , Ryason P. R. , Yeh S. W.
Published: August 2006

In response to regulatory requirements, lubricant manufacturers are seeking oils that minimize soot thickening and the accompanying soot wear. Formulation technology is being developed by additive manufacturers to satisfy these requirements. For example, such work is in progress at Chevron Oronite Company LLC, using the Cummins M-11 exhaust gas recirculation (EGR) engine test as a surrogate for the anticipated soot wear test for PC-10. Simultaneously, the authors developed bench tests to screen candidate formulations and reduce costs.

A ball-on-disc sliding wear test, using a PCS Instruments MTM® tribometer, has been investigated. Sliding conditions at high pressure are required for soot polishing wear. Conditions that correlate tribometer test results with M-11 engine results at high soot concentrations (∼9 per cent) have been found. Both ball wear and Stribeck curves were determined in these tests. The high-wear oil progresses from mixed lubrication conditions to boundary lubrication at higher sliding speeds than the low-wear oil. X-ray photoelectron spectroscopy experiments were also conducted on the ball wear scars, revealing differences in the chemical constitution of the tribofilms from the two oils.
Analysis of the Behaviour of Rolling Bearings in Contaminated Oil Using Some Condition Monitoring Techniques
Authors: Akagaki T , Nakamura M , Monzen T , Kawabata M
Published: August 2006

Friction and wear behaviours of rolling bearing in contaminated oil containing white-fused alumina particles were studied. The friction and wear processes were monitored using wear debris analysis, such as ferrography and spectrometric oil analysis program, and vibration analysis. Test bearing was a deep groove ball bearing (6002P5); Wear debris and worn surfaces of the bearing components were observed with a scanning electron microscope (SEM).

It was found that the friction coefficient in the contaminated oil became lower by about 0.001 than that in the new oil for the large contaminants. The results of wear debris analysis showed that the large contaminants caused the high wear rate in the bearing. Three types of wear debris were commonly observed: thread-like debris, cutting chip debris, and plate-like debris. On the basis of the SEM observation results of the worn surfaces, wear mechanisms of these wear debris were discussed. The results of vibration analysis showed that the probability density function of vibration waveform was normal distribution in both the new and contaminated oils. In the contaminated oil, it changed depending on the contaminant size and the runtime, i.e. the progress of wear in the bearing. The result of wear debris analysis was related to that of vibration analysis and discussed.
Effect of Contamination on the Performance of Hydrodynamic Bearings
Authors: Khonsari M. M. , Booser E. R.
Published: August 2006

This paper surveys three areas: experimental evaluations and operating experience relating to contaminant detrimental effects to the particle size and hardness; importance of film thickness; and self-propagating damage with high-chromium steel rotors and chlorine oil additives. Analytical thermal criteria are also presented for a particle size limit to avoid flash temperature scuffing failures from particles embedding in a bearing at a sliding surface contact.
Environmental Improvements in Ship Design by the Use of Scoring Functions
Authors: Winnes H , Ulfvarson A
Published: August 2006

The introduction of environmental aspects in ship design requires a holistic view of the design process. The designer needs to integrate environmental knowledge with the design process without increasing calendar time for the design work. A design tool that supports trade-off analyses with environmental objectives will be presented in this paper.

Interviews with experienced ship designers have been conducted to support the mapping of the ship design process. This has resulted in identification of decision points, where environmental aspects could be addressed, and has shown the possibilities of the aforementioned integration.

The aim has been to show a design tool that is able to manage geographical differences in sensitivity, when it comes to environmental effects from a ship. The paper will point out changes in approach to include this tool in the design process.

This paper demonstrates so-called scoring functions in-a trade-situation with environmental information. The tool produced keeps a lot of information ready at an early stage in the design process and deals with the issue of changing environmental sensitivity in the ship surroundings. Recommendations are given on further development for the use of environmentally focused scoring functions in ship design.
Adaptive Roll Stabilization of Fishing Vessels
Authors: Jones E B , Roskilly A P , Webster B , Birmingham R W
Published: August 2006

The application of frequency adaptive anti-roll tanks on fishing vessels is well established but currently restricted to U-tube designs. This paper concerns the initial stages of a research programme to develop a more generic anti-roll system that will be applicable to a range of tank geometries, with minimal alteration to the existing tank structure. Two possible control strategies, based on continuous and intermittent fluid flow, are assessed for a U-tube tank and the potential of extending the technique to a free-surface tank with a central partition is examined. The intermittent flow scheme was found to be most effective at longer roll periods while the continuous flow scheme was heavily reliant on a low value of fluid flow resistance.
Structural Safety Analysis of Bow Doors
Authors: Karlsson U B , Ulfvarson A
Published: August 2006

Bow doors are one of the most vulnerable parts on a RoRo vessel. At the same time, they are necessary for the profitability of today's RoRo vessels.

The minimum design rules for bow-door systems, stated in the International Association of Classification Societies (IACS) UR S8, constitute the basis for the class rules. In this work, the Rules of IACS UR S8 have been assessed regarding the structural integrity for bow doors of the ‘clam door’ type. The work is based on previous damage, compared to the design rules, so as to find weaknesses in the rules. Damage was mapped and weak points in the rules as well as in the design and construction stages were identified. For the problem areas found, part analyses were performed.

Fractures and cracks dominate as being the cause of damage to bow-door systems. In most of these cases, cracks in welds are involved. Fatigue appears to be a major cause for the development of fractures and cracks. Assuming the bow door as being a rigid body and distributing the forces equally on each support, as prescribed by IACS UR S8, appears to be an approach that leads to inadequate results. The deformation of the door causes the loads on the supports to differ significantly and the real pressure distribution subjects the lower supports to much higher loads then the upper ones. It is common with gaps between the supports in the doors and the corresponding ones in the hull. These gaps considerably affect the load distribution on the supports.
Effective role redesign: an audit of outcomes following the introduction of a new nurse-led service
Authors: Challenor Rachel , Henwood Elizabeth , Burgess Janet , Clare Daniel
Published: August 2006

Genitourinary medicine services have had to modernize to try to meet the growth in demand. Changes should be audited to ensure standards remain high. We introduced a 'comprehensive care nurse-led service' for patients presenting for asymptomatic screening and as asymptomatic contacts (partners of known positive patients). Following implementation we audited outcomes and patient satisfaction. During the audit period (01/07/2005 to 30/11/2005), 446 patients were seen. A sexual health screen was performed in 433 (216 females: 217 males). Forty-one patients (9.5%) were chlamydia-positive by enzyme-linked immunosorbent assay testing (background clinic rate 8.5%). Forty-six (10.6%) were treated epidemiologically as chlamydia-negative contacts of chlamydia-positive index patients and 18 (4.1%) were treated as chlamydia-negative urethritis/cervicitis. Uptake of HIV testing was 71.2% (311/433). Average wait-to-appointment was three days (background clinic wait 2–3 weeks). Nurse-led clinics were judged successful in terms of outcomes, improving access and patient satisfaction.
How many sexually transmitted infections (STIs) will we miss? — an algorithm to assess risk factors for STI
Authors: Al Sharqi A , Thompson C , Clutterbuck D J
Published: August 2006

A self-administered algorithm for the assessment of symptoms of, and risk factors for, sexually transmitted infection (STI) was developed. The algorithm was applied retrospectively to all cases of STI other than chlamydia diagnosed over a one-year period, to estimate the risk of missing STI diagnoses by its introduction. Three hundred and eighty-nine cases were identified, of whom 81 (21%) were asymptomatic. Seven asymptomatic cases had no identifiable risk factors for infection and might potentially have been offered a postal testing kit for chlamydia rather than a full STI screen. We estimate that 1.8% of STIs diagnosed in the unit might be missed by the introduction of the algorithm.
Prevalence of infection by HTLV-I/II among pregnant women and high-risk groups in the Peloponnese peninsula, Greece
Authors: Tseliou Parthenopi M , Spanakis Nicholas , Spiliotakara Anna , Markogiannakis Antonios , Legakis Nicholas J , Tsakris Athanassios
Published: August 2006

Although screening for human T-cell lymphotropic virus types I and II (HTLV–I/II) antibodies in volunteer blood donors has been systematic in Greece since 1995, the epidemiology and the determinants of HTLV-I/II infection are not well defined among population groups. During 1997–2005, the prevalence of HTLV-I/II infection was investigated in a sample of 2016 pregnant women, 102 multitransfused haematologic and oncologic patients, 93 thalassaemic patients and 57 intravenous drug users originating from four geographic areas of Pelopennese peninsula, Greece. One recipient of HTLV-I infected blood and the relatives of a woman died from adult T-cell leukaemia/lymphoma (ATTL) related to HTLV-I have also been tested. The subjects were initially screened by an enzyme immunoassay whereas Western blot, INNO-LIA HTLV, polymerase chain reaction and nucleotide sequencing confirmed the infection. One thalassaemic patient had proved HTLV-I infection giving an overall prevalence of 11 per 1000. In the recipient of the infected blood and in two of the five relatives of the woman died from ATTL, HTLV-I infection was also detected. In none of the pregnant women, multitransfused patients and intravenous drug users HTLV-I/II infection was confirmed. These data suggest that HTLV-I is present in Greece among populations at high-risk. However, they would not support the need for HTLV-I/II antenatal screening in Greece.
Enrolment of 22,000 adolescent women to cancer registry follow-up for long-term human papillomavirus vaccine efficacy: guarding against guessing
Authors: Lehtinen Matti , Apter Dan , Dubin Gary , Kosunen Elise , Isaksson Rita , Korpivaara Eeva-Leena , Kyhä-Österlund Laura , Lunnas Terhi , Luostarinen Tapio , Niemi Lubov , Palmroth Johanna , Petäjä Tiina , Rekonen Sirpa , Salmivesi Susanna , Siitari-Mattila Mari , Svartsjö Sofia , Tuomivaara Leena , Vilkki Marjo , Pukkala Eero , Paavonen Jorma
Published: August 2006

Human papillomaviruses (HPVs, most notably types 16 and 18) cause cervical carcinoma, the second most common cancer among women. Vaccination of adolescents against HPV16/18 might prevent large proportion of cervical and other anogenital cancers. However, because of ethical reasons this cannot be proven by clinical studies. To determine the long-term vaccine efficacy (VE) of HPV16/18 virus-like-particle (VLP) vaccine against cervical carcinoma in situ (CIS+) and invasive cervical carcinoma, the following three population-based cohorts of adolescent women have been enrolled: (1) women vaccinated with the HPV vaccine; (2) women vaccinated with hepatitis A control vaccine; and (3) unvaccinated control women. These cohorts will be passively followed for cumulative incidence of CIS+ endpoints by population-based cancer registry. Overall 24,046 16- to 17-year-old adolescent women from 18 cities in Finland were invited between May 2004 and June 2005 to participate in a phase III trial with bivalent HPV16/18 VLP vaccine. A total of 58,996 18- to 19-year-old women were invited in May 2005 to participate as unvaccinated controls. Women who reported their willingness to participate in an HPV vaccination trial had they been 1–2 years younger were eligible. Cumulative incidence (CI) of CIS+ in our cohorts over 15 years is approximately 0.45%. VE of 70% against CIS+ with 80% power requires 3357–3189 HPV16/18 vaccine recipients, 3357–3189 other vaccine recipients, and 6714–9567 unvaccinated controls. We have now enrolled 2404 HPV16/18 vaccine recipients, 2404 hepatitis A-vaccine recipients, and 5130 unvaccinated controls. This enrolment in addition to our earlier enrolment in another phase III trial guarantees enough power so that by 2020 we can ultimately provide data on the efficacy of HPV16/18 vaccination against CIS+.
Septic shock and multi-organ failure in HIV infection-'sepsis tuberculosa gravissima'
Authors: Ferrand Rashida A , Herman Joanna , Elgalib Ali , Cartledge Jonathan , Miller Robert F
Published: August 2006

A profoundly immunosuppressed HIV-infected man developed sepsis syndrome with multi-organ failure. A septic screen failed to identify a bacterial or fungal cause and despite empirical treatment for these pathogens the patient remained unwell. Investigations revealed disseminated tuberculosis. With specific anti-tuberculosis therapy the patient rapidly recovered. Although most cases of sepsis syndrome in HIV-infected patients are due to bacteria, tuberculosis should be added to the differential diagnosis of this presentation.
The cost of antiretroviral drugs and influence on prescribing policies
Authors: Jones Rachael , Gazzard Brian
Published: August 2006

With the advent of highly active antiretroviral therapy (HAART), the prognosis for HIV-infected individuals with access has been transformed. HAART provides one of the most cost-effective treatments for any chronic disease. Immediate cost remains a legitimate factor when chosing HAART regimens, however, the cost of long-term side-effects and adherence issues must also be considered. The review examines the cost issues associated with HAART prescription and its influence on prescribing policies.
Characteristics of younger and older men with urethral chlamydial infection
Authors: Arnot D J , Manavi K , McMillan A
Published: August 2006

This study examined some characteristics of male clinic attenders with urethral chlamydial infection. The prevalence of urethral chlamydial infection among heterosexual men (men who have sex with women [MSW]) was 446 (17%) of 2684 men.

Men aged 16–34 years were more likely to have chlamydiae than older men with only casual partners (χ2 = 16.08; P = 0.001). Infected younger men with casual partners had more partners than uninfected men (median 2.0 [interquartile range [IQR] 1.0] versus 1.0 [IQR 1.0]) ( P<0.05). However, this was not true of older men (median number of partners 1.0 [IQR 1.0] versus 1.0 [IQR 1.0]) ( P>0.05).

Consistent condom use by younger but not by older men was associated with a lower prevalence of chlamydial infection compared with those whose use of condoms was inconsistent (χ2 = 19.75; P<0.001).

Our results suggest that chlamydia testing should be offered to any MSW, irrespective of his age, who has had a new partner.
The changing prevalence of hepatitis B virus infection among men who have sex with men who attended a sexually transmitted infections clinic in Edinburgh, Scotland between 1989 and 2003
Authors: McMillan Alexander
Published: August 2006

The aim of the study was to discover if the prevalence of serological markers of hepatitis B virus infection among men who have sex with men (MSM) who attended a sexually transmitted infections clinic in Edinburgh, Scotland had changed in a 15-year period. This was a retrospective study of 3334 MSM attending the clinic as new patients. Forty-four men (1%) had hepatitis B surface antigenaemia. Overall, sera from 398 (12%) men gave positive results for anti-HBc. The seroprevalence of HBV in men aged 25–34 years and older men declined significantly during the study period. There was no significant change in seropositivity for anti-HBc in men aged 16–24 years. The proportion of men who had been vaccinated previously rose significantly during the most recent three-year period. Although there has been a decline in the prevalence of infection in clinic attendees, there is continued transmission of HBV in the local community.
Medical student attitudes towards HIV
Authors: Ivens D , Sabin C
Published: August 2006

The aim of the study was to determine medical student attitudes towards HIV-related issues, to examine if the following student factors can affect attitudes: gender, perception of HIV infectivity, exposure to an HIV+ individual, career intent and attending a clinical attachment.

A self-administered questionnaire was given to students at the beginning and end of a clinical attachment.

Of the 240 questionnaires handed out at the beginning of the attachment, 183 (76%) were completed. Students generally expressed positive attitudes towards people with HIV. Female students and individuals who had considered working in a related specialty or had met an HIV+ person expressed more patient-centred attitudes in some of their responses. Following the course, 72 questionnaires were returned. Responses to several of the attitudinal statements had changed significantly.

Medical students generally have enlightened attitudes towards HIV-related issues, which may be affected by student factors and attending a clinical attachment.
Severe osteoporosis and multiple fractures in an AIDS patient treated with short-term steroids for lymphoma: a need for guidelines
Authors: Panayotakopoulos George D , Day Sarah , Peters Barry S , Kulasegaram Ranjababu
Published: August 2006

An HIV-1 infected patient on dual protease inhibitor treatment developed spontaneous vertebral fractures and avascular necrosis of the femoral bone after receiving combined chemotherapy for Burkitt's lymphoma including short-term prednisolone. The factors involved in the pathogenesis of osteopaenia and osteoporosis in this case are discussed and we propose the need for guidelines in order to reduce the incidence of such events in HIV-infected patients in the future.
Comparison of time to undetectable HIV viral load in the first 16 weeks after the start of three and four antiretroviral regimens
Authors: Manavi K , Scott G
Published: August 2006

The aim of this paper is to compare the time to a viral load <50 copies/mL of three or four antiretroviral therapy (ART) regimens among ART naïve patients within the first 16 weeks after the start of treatment. A retrospective study was carried out on ART naïve patients who started HAART between 1 January 1999 and 1 January 2004. ART naïve patients with a viral load >5.3 log10 copies/mL at the time of treatment were routinely started on four ART regimens in one of the HIV centres in Edinburgh. These patients were compared with ART naïve patients with viral load >5.3 log10 copies/mL at the time of start of three ART regimens in the other centre within the study period. During the study period, of 93 ART naïve patients with a viral load >5.3 log10 copies/mL, 56 and 37 commenced four drug and three drug regimens, respectively. Patients in each group were matched for their age, prevalence of HCV, median age, and median viral load at the start of therapy; however, patients on three drug regimens had significantly lower CD4 counts ( P<0.01). The median time to undetectable viral load was 13.5 weeks for three and four drug regimens ( P>0.05). By the time of undetectable viral load, there was no difference in the CD4 count of patients on three or four drug regimens. Similar proportions of immunosuppressed patients on three and four ART regimens had undetectable viral load within the first 16 weeks of therapy.
Timing of highly active antiretroviral therapy and chemotherapy for Kaposi's sarcoma in patients with HIV infection
Authors: Loke W C , Spittle M F , Mitchell S , Kulasegaram R
Published: August 2006

Highly active antiretroviral therapy (HAART) is an important part of the treatment of Kaposi's sarcoma (KS) in HIV-infected patients. We describe two cases of KS, which worsened on HAART.
Confidentiality is essential if young people are to access sexual health services
Authors: Thomas N , Murray E , Rogstad K E
Published: August 2006

A survey was undertaken to determine the importance of confidentiality of sexual health clinics to young people, and their preferences for service provision. A questionnaire was given to school attenders in year 9 (age 13–14 years) at four comprehensive schools. Class leaders assisted students with literacy or language difficulties.

Two hundred and ninety five questionnaires were distributed and all were returned (male 143 (48.5%), female 152 (51.5%). In all 199 (67.5%) had never used sexual health services. The importance of confidentiality (asked in two differently worded questions) was rated as 8.84 and 8.59 (mean) on a scale of 1 (not important) to 10 (very important), 166 (56.3%) rated confidentiality as most important feature of service and 254 (86.1%) were more likely to use a service if it was confidential; 161 (54.6%) would not use service if it were not confidential. Two hundred and sixty-six (90.2%) would give honest answers in a confidential service; 186 (63.1%) would not attend if they thought that child protection services would be informed; 136 (46.1%) would not want general practitioner informed of attendance; 209 (70.8%) would like regular sexual health check ups; 150 (50.8%) would prefer a young people clinic, but only 105 (35.6%) prefer a 'one-stop shop'.

This study shows that confidentiality is extremely important to young people considering using a sexual health service. It is the first UK study to show that if confidentiality is lost, young people may not attend, or may not be honest when they utilize a sexual health service. This is particularly relevant at the moment in light of the threat to confidentiality for young people attending sexual health services.
Heterosexual men and women who seek sex through the Internet
Authors: Bolding Graham , Davis Mark , Hart Graham , Sherr Lorraine , Elford Jonathan
Published: August 2006

Heterosexual women ( n = 330), heterosexual men ( n = 319) and gay men ( n = 331) attending a London HIV-testing clinic in 2002–03 completed a confidential self-administered questionnaire concerning their sexual behaviour and use of the Internet for seeking sexual partners (response rate 70%). One-in-twenty (5%) heterosexual women and one-in-ten (10%) heterosexual men had used the Internet to look for sexual partners in the previous 12 months compared with nearly half (43%) the gay men ( P<0.001). Rates of high-risk sexual behaviour with a casual partner were elevated among those who used the Internet to look for sex (compared with those who did not). However, people who looked for sex through the Internet were just as likely to meet their high-risk casual partners offline as online. Our findings suggest that high-risk heterosexual women and men are selectively using the Internet to look for sex rather than the Internet per se leading to riskier sexual behaviour.
The recurrence of cervical intraepithelial neoplasia in HIV-positive women: a review of the literature
Authors: Tebeu Pierre Marie , Major Attila L , Mhawech Paulette , Rapiti Elisabetta
Published: August 2006

The objective of this study was to assess the available evidence on the outcome of cervical intraepithelial neoplasia (CIN) in HIV-positive women after conization. We performed a literature search of Medline and Cochrane libraries to locate published articles reporting about the rate of recurrence of CIN after excisional treatment in patients with negative surgical margins. Out of 15 articles, five studies reported recurrence rate of CIN in margin negative patients. The recurrence rate of CIN after conization in HIV-infected women ranges from 20% to 75%. No conclusions can be drawn about the impact of CD4 cell counts on the recurrence rate. Available evidence suggests that standard excisional treatments for CIN are associated with high rates of recurrence in HIV-positive women. Despite the fact that the evidence is limited because of the few number of eligible studies, this issue should be considered in the management of HIV-positive patient with CIN.
Dissemination of Strongyloides stercoralis as an immune restoration phenomenon in an HIV-1-infected man on antiretroviral therapy
Authors: Brown M , Cartledge J D , Miller R F
Published: August 2006

We present a case of Strongyloides stercoralis infection in an HIV-infected man, resulting in Escherichia coli meningitis after initiation of antiretroviral therapy. Recent evidence from studies of strongyloides development supports the concept that strongyloides dissemination in this case is an example of an immune reconstitution inflammatory syndrome.
Circumcision in Australia: prevalence and effects on sexual health
Authors: Richters Juliet , Smith Anthony M A , de Visser Richard O , Grulich Andrew E , Rissel Christopher E
Published: August 2006

The results from a telephone survey in 2001–02 of a probability sample of Australian households including 10,173 men aged 16–59 (response rate 69.4%) are used to assess the prevalence of circumcision across social groups in Australia and examine lifetime history of sexually transmissible infection (STI), sexual difficulties in the last year, sexual practices including masturbation, and sexual attitudes.

More than half (59%) of the men were circumcised. Circumcision was less common among younger men (32% aged <20) and more common among the Australian born (69%). After correction for age, circumcision was unrelated to reporting STI, but appeared to protect against penile candidiasis. Circumcision was unrelated to most sexual difficulties, but circumcised men were less likely to report physical pain during intercourse or trouble keeping an erection; reasons for this are unknown. There were no significant differences in practices at last sexual encounter with a female partner or in masturbation alone. Circumcised men had somewhat more liberal sexual attitudes.

Neonatal circumcision was routine in Australia until the 1970s. It appears not to be associated with significant protective or harmful sexual health outcomes. This study provides no evidence about the effects on sexual sensitivity.
Oscillating kissing stem–loop interactions mediate 5′ scanning-dependent translation by a viral 3′-cap-independent translation element
Authors: Rakotondrafara Aurélie M. , Polacek Charlotta , Harris Eva , Miller W. Allen
Published: August 2006

The 3′-untranslated regions (UTRs) of a group of novel uncapped viral RNAs allow efficient translation initiation at the 5′-proximal AUG. A well-characterized model is the Barley yellow dwarf virus class of cap-independent translation elements (BTE). It facilitates translation by forming kissing stem–loops between the BTE in the 3′-UTR and a BTE-complementary loop in the 5′-UTR. Here we investigate the mechanisms of the long-distance interaction and ribosome entry on the RNA. Upstream AUGs or 5′-extensions of the 5′-UTR inhibit translation, indicating that, unlike internal ribosome entry sites in many viral RNAs, the BTE relies on 5′-end-dependent ribosome scanning. Cap-independent translation occurs when the kissing sites are moved to different regions in either UTR, including outside of the BTE. The BTE can even confer cap-independent translation when fused to the 3′-UTR of a reporter RNA harboring dengue virus sequences that cause base-pairing between the 3′- and 5′-ends. Thus, the BTE serves as a functional sensor to detect sequences capable of long-distance base-pairing. We propose that the kissing interaction is repeatedly disrupted by the scanning ribosome and re-formed in an oscillating process that regulates ribosome entry on the RNA.
Factors related to perceived power usage in schools
Authors: Schwarzwald Joseph , Koslowsky Meni , Brody‐Shamir Shlomit
Published: August 2006

Based onRaven's (1992)power interaction model, situational and personal variables were examined as determinants of power choice in educational settings. The impact of educational sector (secular, religious), class level, gender and content of conflict on perceived power usage in teacher–pupil conflicts was analysed. A total of 370 elementary and junior high school pupils and 62 teachers from the same schools responded to a series of scenarios where they were asked how often specific power bases are used by teachers in trying to gain compliance. Results indicated that harsh power bases were perceived as more prevalent in the secular educational sector rather than in the religious one, in junior high school rather than elementary school, for boys as compared with girls, and for conflicts stemming from students rather than teachers. Findings were interpreted in terms of conformity level and frequency of conflicts. The discussion also addresses the lack of correspondence between teacher and pupil responses.