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Background Organ transplant recipients (OTRs) have up to 500-fold increased risk of keratinocyte skin cancer (KSC). International guidelines recommend at least annual skin cancer screening for OTRs. Objectives To explore the current skin cancer surveillance practice in UK transplant centres across all solid organs and the barriers to surveillance. Materials and methods An online survey was sent to all 59 transplant centres in the UK specialising in kidney (n = 24), pancreas (n = 10), heart and/or lung (n = 13), liver (n = 8) and intestine (n = 4) transplants. Results Fifty-one (86%) transplant centres responded. Twenty-eight (55%) centres provided skin cancer surveillance post-transplantation, of which 18 (64%) had a non-skin cancer specialist providing screening. Only 21 (41%) units performed a full skin examination. Eight units (29%) screened at least bi-annually in the first five years post-transplantation. Of the 23 (45%) centres that did not provide skin cancer surveillance, limitations included: reliance on patient-reported lesions (48%), lack of skin surveillance training (30%), lack of funding (48%), not a requirement in all patients (17%) and time restraints in the clinic (30%). Conclusion In the UK, many transplant units do not provide skin surveillance. Collaboration between skin cancer and transplant specialists would improve surveillance rates and reduce morbidity and mortality.

Introduction The severity of Covid-19 infection is associated with viral load. For infection to occur, viruses including SARS-CoV-2 must first penetrate the respiratory mucus to attach to the host cell surface receptors. Iota-carrageenan (I-C), a sulphated polysaccharide extracted from red edible seaweed, has shown efficacy against a range of viruses in clinical trials, through prevention of viral entry into respiratory host cells and in-vitro activity against SARS-CoV-2. Our aim, as an academic surgical department, was to design and implement a clinical trial to investigate whether I-C nasal and throat sprays are effective in reducing the rate and severity of Covid-19 infection. Method The study is a single centre, double-blinded randomised controlled trial. Recruitment of 480 participants aged ≥18 years without previous Covid-19 infection and who have not yet been vaccinated, commenced in December 2020. Participants are randomised to either the treatment (0.12% I-C in 0.5% saline spray) or placebo (0.5% saline spray) arm and will prophylactically apply the spray to their nose and throat while completing a daily symptom tracker for a total of 10 weeks. The primary outcome is the acquisition of Covid-19 infection. Secondary outcomes include symptom type, severity and duration, subsequent familial/household Covid-19 infection and infection with non-Covid-19 upper respiratory tract infections. Discussion Our hypothesis is that I-C sprays will reduce SARS-CoV-2 attachment to the naso- and oropharyngeal mucosal epithelial cells thus reducing the effective viral infective dose. If proven effective, the self-administered prophylactic spray would have wider utility for key workers and the general population. Trial registration number NCT04590365

Skin cancer is more common in transplant recipients, although the quoted incidence is variable. This study investigated the incidence of skin cancer in solid organ transplant recipients (OTRs) in a national cohort and the effect of pharmacotherapeutic agents Transplant patients were identified from Patient Episode Database for Wales (PEDW) using Office of Population Census and Surveys Classifications of Interventions and Procedures-4 (OPCS-4) codes. Controls were matched to cases according to age, sex and socioeconomic status. Skin cancer data were obtained from linkage with other national data sources. Incidence was calculated per 100,000 person-years at risk (PYAR). Negative binomial regression was used to calculate adjusted incidence rate ratios (IRRs) for each organ type. During 2000-2018, 2,852 Welsh patients underwent solid organ transplantation. A total of 13,527 controls were matched from the general population. The incidence of skin cancer within the OTR cohort was 1203.2 per 100,000 PYAR vs 133.9 in the matched control group. Age, male gender and azathioprine use were all associated with an increased risk of skin cancer. Contemporary immunomodulators such as tacrolimus and mycophenolate were associated with a reduction in skin cancer risk when compared to their predecessors, cyclosporin and azathioprine. The highest adjusted IRR was observed in heart transplant recipients (IRR: 10.82; 95% CI: 3.64-32.19) and the lowest in liver transplant recipients (IRR: 2.86; 95% CI: 1.15-7.13). This study highlights the need for long-term routine skin cancer surveillance for all OTRs and the importance of using contemporary immunomodulators, when possible, for risk reduction.

Background Previous studies have identified an inverse association between melanoma and smoking; however, data from population-based studies are scarce. Objectives To determine the association between smoking and socioeconomic (SES) on the risk of development of melanoma. Furthermore, we sought to determine the implications of smoking and SES on survival. Methods We conducted a population-based case-control study. Cases were identified from the Welsh Cancer Intelligence and Surveillance Unit (WCISU) during 2000-2015 and controls from the general population. Smoking and SES were obtained from data linkage with other national databases. The association of smoking status and SES on the incidence of melanoma were assessed using binary logistic regression. Multivariate survival analysis was performed on a melanoma cohort using a Cox proportional hazard model using survival as the outcome. Results During 2000-2015, 9636 patients developed melanoma. Smoking data were obtained for 7124 (73·9%) of these patients. There were 26 408 controls identified from the general population. Smoking was inversely associated with melanoma incidence [odds ratio (OR) 0·70, 95% confidence interval (CI) 0·65-0·76]. Smoking was associated with an increased overall mortality [hazard ratio (HR) 1·30, 95% CI 1·09-1·55], but not associated with melanoma-specific mortality. Patients with higher SES had an increased association with melanoma incidence (OR 1·58, 95% CI 1·44-1·73). Higher SES was associated with an increased chance of both overall (HR 0·67, 95% CI 0·56-0·81) and disease-specific survival (HR 0·69, 95% CI 0·53-0·90). Conclusions Our study has demonstrated that smoking appeared to be associated with reduced incidence of melanoma. Although smoking increases overall mortality, no association was observed with melanoma-specific mortality. Further work is required to determine if there is a biological mechanism underlying this relationship or an alternative explanation, such as survival bias. What's already known about this topic? Previous studies have been contradictory with both negative and positive associations between smoking and the incidence of melanoma reported. Previous studies have either been limited by publication bias because of selective reporting or underpowered. What does this study add? Our large study identified an inverse association between smoking status and melanoma incidence. Although smoking status was negatively associated with overall disease survival, no significant association was noted in melanoma-specific survival. Socioeconomic status remains closely associated with melanoma. Although higher socioeconomic populations are more likely to develop the disease, patients with lower socioeconomic status continue to have a worse prognosis.

The FACE-Q Skin Cancer module is a patient-reported outcome measure (PROM) for facial skin cancer. It has been anglicised for the UK population and undergone psychometric testing using classical test theory. In this study, further evaluation of construct validity using Rasch measurement theory and hypothesis testing was performed.Patients were prospectively recruited to the Patient-Reported Outcome Measures In Skin Cancer Reconstruction (PROMISCR) study and asked to complete the anglicised FACE-Q Skin Cancer module. The scalability and unidimensionality of the data were assessed with a Mokken analysis prior to Rasch analysis. Response thresholds, targeting, fit statistics, local dependency, and internal consistency were examined for all items and subscales. Four a priori hypotheses were tested to evaluate the convergent and divergent validity. We additionally hypothesised that the median 'cancer worry' score would be lower in post-operative than pre-operative patients.239 patients self-completed the questionnaire between August 2017 and May 2019. Of the ten subscales assessed, five showed relative fit to the Rasch model. Unidimensionality was present for all five subscales, with most demonstrating ordered item thresholds and appropriate fit statistics. Two items in the 'cancer worry' subscale had either disordered or very close response thresholds. Subscales of the FACE-Q Skin Cancer module demonstrated convergent and divergent validity with relevant Skin Cancer Index comparators (p 0.001). Median 'cancer worry' was lower in post-operative patients (44 vs 39, p 0.001).The anglicised FACE-Q Skin Cancer module shows psychometric validity through hypothesis testing, and both classical and modern test theory.

ObjectivesTo report the volume of surgical activity and the number of cancelled surgical procedures during the COVID-19 pandemic.Design and settingAnalysis of electronic health record data from the National Health Service (NHS) in England and Wales.MethodsWe used hospital episode statistics for all adult patients undergoing surgery between 1st January 2020 and 31st December 2020. We identified surgical procedures using a previously published list of procedure codes. Procedures were stratified by urgency of surgery as defined by NHS England. We calculated the deficit of surgical activity by comparing the expected number of procedures from the years 2016-2019 with the actual number of procedures in 2020. We estimated the cumulative number of cancelled procedures by 31st December 2021 according patterns of activity in 2020.ResultsThe total number of surgical procedures carried out in England and Wales in 2020 was 3,102,674 compared to the predicted number of 4,671,338. This represents a 33.6% reduction in the national volume of surgical activity. There were 763,730 emergency surgical procedures (13.4% reduction), compared to 2,338,944 elective surgical procedures (38.6% reduction). The cumulative number of cancelled or postponed procedures was 1,568,664. We estimate that this will increase to 2,358,420 by 31st December 2021.ConclusionsThe volume of surgical activity in England and Wales was reduced by 33.6% in 2020, resulting in over 1,568,664 cancelled operations. This deficit will continue to grow in 2021.Summary boxesWhat is already known on this topicThe COVID-19 pandemic necessitated a rapid change in the provision of care, including the suspension of a large proportion of surgical activitySurgical activity has yet to return to normal and has been further impacted by subsequent waves of the pandemicThis will lead to a large backlog of casesWhat this study adds3,102,674 surgical procedures were performed in England and Wales during 2020, a 33.6% reduction on the expected yearly surgical activityOver 1.5 million procedures were not performed, with this deficit likely to continue to grow to 2.3 million by the end of 2021This deficit is the equivalent of more than 6 months of pre-pandemic surgical activity, requiring a monumental financial and logistic challenge to manage

ObjectivesTo confirm the incidence of perioperative SARS-CoV-2 infection and associated mortality after surgery.Design and settingAnalysis of routine electronic health record data from National Health Service (NHS) hospitals in England.MethodsWe extracted data from Hospital Episode Statistics in England describing adult patients undergoing surgery between 1st January 2020 and 31st October 2020. The exposure was SARS-CoV-2 infection defined by ICD-10 codes. The primary outcome measure was 90-day in-hospital mortality. Data were analysed using multivariable logistic regression adjusted for age, sex, Charlson co-morbidity index, index of multiple deprivation, presence of cancer, surgical procedure type and admission acuity. Results are presented as n (%) and odds ratios (OR) with 95% confidence intervals.ResultsWe identified 1,972,153 patients undergoing surgery of whom 11,940 (0.6%) had SARS-CoV-2. In total, 19,100 (1.0%) patients died in hospital. SARS-CoV-2 infection was associated with a much greater risk of death (SARS-CoV-2: 2,618/11,940 [21.9%] vs No SARS-CoV-2: 16,482/1,960,213 [0.8%]; OR: 5.8 [5.5 – 6.1]; pConclusionsThe low incidence of SARS-CoV-2 infection in NHS surgical pathways suggests current infection prevention and control policies are highly effective. However, the high mortality amongst patients with SARS-CoV-2 suggests these precautions cannot be safely relaxed.Summary boxesWhat is already known on this topicHigh mortality rates have been reported amongst surgical patients who develop COVID-19 but we don’t know how this compares to the concurrent surgical population unaffected by COVID-19.Strict infection prevention and control procedures have substantially reduced the capacity of surgical treatment pathways in many hospitals.The very large backlog in delayed and cancelled surgical procedures is a growing public health concern.What this study addsFewer than 1 in 100 surgical patients are affected by COVID-19 in the English National Health Service.Elective surgical patients who do develop COVID-19 are 30 times more likely to die while in hospital.Infection prevention and control procedures in NHS surgical pathways are highly effective but cannot be safely relaxed.

Summary Background Prominent ears are the most common congenital abnormality of the head and neck, occurring in 5% of the Caucasian population. Facial disfigurement can cause psychosocial distress, low self-esteem and varying levels of social isolation most notable in school-age children. Although prominent ear correction is the most frequently performed aesthetic operation in children and adolescents, to our knowledge, the relationship between prominent ears and psychological, social and educational issues has not been systematically assessed. Purpose of study To investigate the psychological, social and educational impact of prominent ears and to examine how prominent ear correction affects health-related quality of life (HRQoL). Methods A systematic review was conducted using a protocol registered with PROSPERO and in line with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses statement. A comprehensive search of the literature was conducted using MEDLINE, EMBASE, PyscINFO, HMIC Health Management Information Consortium, Ovid Journals Database, NHS Wales Full-Text Journals and The Cochrane Database. The inclusion criteria stated that any study investigating the association between psychological, social or educational issues, or HRQoL and prominent ears or otoplasty should be incorporated. All studies were reviewed by two authors, with data extracted for the studies finally included. Findings Fourteen articles were finally included, with a total of 786 patients. Thirteen out of 14 papers analysed the post-operative effect of surgical correction of prominent ears. The most common motivating factor for surgery was bullying, with young males of school age being the worst affected. Prominent ear patients report higher levels of bullying and social problems, and lower levels of physical activity than patients with more severe facial disfigurements. Every study that assessed the psychosocial impact of surgery on prominent ears found a significant benefit to HRQoL. Conclusion and relevance Prominent ears pose severe psychological and social issues that should not be underestimated. Surgical correction has consistently been shown to significantly improve HRQoL.

Background Seizure recurrence after a fit has implications for both individuals and healthcare providers guiding neurologic prognosis, treatment, and driving and work restrictions. A systematic review of long-term seizure recurrence after eclampsia will help to quantify recurrence risk in this setting. Objective To evaluate the long-term recurrence of seizures after eclampsia. Search strategy After PROSPERO registration, Medline (Ovid), Embase, and Cochrane Library were searched by using the terms (eclampsia OR eclamp* OR eclamptic seizure* OR eclamptic fit*) AND (recur* OR recurrent fit* OR recurrent seizure*) for studies published up until December 2019. Selection criteria Studies describing long-term seizure recurrence after a diagnosis of eclampsia were included. Data collection and analysis Data were extracted from studies independently by two authors. Pooled prevalence was calculated and weighted based on sample size with a 95% confidence interval (CI). Main results Initially, 1754 unique studies were identified and 4 were included in the final analysis. The studies involved 1896 women, of whom 7 (0.37%) were affected by a further seizure. The weighted pooled prevalence of seizure recurrence was 0.18% (95% CI, 0.03-1.02). Conclusion The absolute rate of long-term seizure recurrence after eclampsia is extremely low and within safe limits for driving.

Facial skin cancer is common, and its treatment affects patient's health-related quality of life (HRQoL), as demonstrated by patient-reported outcome measures (PROMs). In this study, we anglicise and validate the novel FACE-Q Skin Cancer Module for the UK population. Anglicisation of the FACE-Q Skin Cancer Module followed international guidance for cross-cultural adaptation. Cognitive interviews were performed, producing a reconciled and harmonised version for validation. Patients undergoing facial skin cancer excision were prospectively recruited and asked to complete the anglicised FACE-Q Skin Cancer Module, along with the Skin Cancer Index (SCI) and European Quality of Life-Five Dimensions (ED-5D) questionnaire, pre-operatively and 6-8 weeks post-operatively. Data were analysed using classical test theory. Ethical approval was obtained (REC: 16/WM/0445). One hundred and ten patients were recruited between August 2017 and July 2018. Internal consistency was high (Cronbach's alpha 0.867-0.967). All subscales had a single-factor solution using principal component analysis. Construct validity, as measured between the FACE-Q subscales and SCI subscales, was good, with >75% of a priori predictions confirmed. Pearson's r for item-total correlation was >0.80 for several items, and significant ceiling effects are shown in 7 of the 10 subscales, suggesting some item redundancy. The UK version of this well-designed PROM demonstrates good face and construct validity. There is however a degree of redundancy within the scales, and further work using Rasch analysis on a larger sample will help address this.

This study proposes a novel approach to determine the fibre volume fraction in composites using vibration based non-destructive technique with a neural network. Currently, the volume fraction of a glass fibre/matrix based composite material is assessed using destructive techniques. Instead of changing or destroying the structure, a new non-destructive approach based on vibration analysis is proposed. Complete experimental protocols were developed to capture the vibration pattern. An auto-regressive model was developed as a feature extraction tool to classify the fibre volume fractions and as a pole tracking algorithm. The classification performances were within the range of 90–98%. For NDT method to be efficient, the classification results were then compared with destructive burn-out technique. The results of non-destructive test showed good agreement with those obtained through destructive test suggesting that the proposed method is an alternative to ASTM D2584-11 for determining the volume fraction of a glass fibre/matrix composite.

The design of composite repairs of corroded oil and gas pipelines must take into account the strength of the interface adhesion between composite and metal. A shaft-loaded blister test is a common method to measure interface fracture toughness and energy release rate. The study aimed on evaluating shaft-loaded blister tests as replacements for more complex pressure blister tests. Specimens investigated were thick fibre-reinforced plates bonded on metal disks as substrates containing a circular through-hole defect. This paper presents the influence of different punch head geometries on the resulting energy release rates and compares the results with blister tests using fluid pressure. Test and simulation results are presented and analytical solutions were derived and evaluated to establish best fitting formulations. It was shown, that significant variations between the different means of loading exist.

The effects of winding angle on the behaviour of glass/epoxy composite tubes under multiaxial cyclic loading were investigated. The performance of such composite tubes was studied using an indigenous automated test procedure that is compatible with the internal qualification requirements of the composite pipe manufacturers. Glass fibre reinforced epoxy (GRE) composite pipes with three winding angles, namely, [±45°]4, [±55°]4, and [±63°]4, were tested. A novel automated test rig was fabricated to accommodate five stress ratios, ranging from pure axial to pure hoop loadings. The cyclic pressure test was conducted until droplets of water were seen on the outer surface of the pipe. Failure envelopes were then constructed based on the first ply failure (FPF) points determined from the axial stress to hoop strain response at five stress ratios. Three functional failure modes, namely, tensile axial, weepage, and local leakage failures, were observed during the tests. The results indicate that each winding angle dominates a different optimum pressure loading condition, namely, [±55°]4 for pure hydrostatic loading, [±45°]4 for hoop to axial loading, and [±63°]4 for quad hoop to axial loading. The envelopes show a strong dependence on the stress ratio and winding angle. Keywords: Glass fibre reinforced epoxy (GRE), Ultimate Elastic Wall Stress (UEWS), First ply failure (FPF), Multiaxial stress ratio, Cyclic loading

Background Facial scarring can have a dramatic effect on a patient's psychological health and wellbeing and present unique management challenges. This patient population remains poorly characterised in the contemporary literature. Aims To evaluate the prevalence of, and risk factors associated with affective disorders in adult patients with facial scars. Methods A systematic review was conducted using a protocol registered with PROSPERO and in line with the PRISMA statement. A comprehensive search of the literature was conducted using PubMed, MEDLINE, EMBASE, PSYCHInfo and The Cochrane Library. Results Twenty one studies were included, with a total of 2,394 participants. Using a random effects model, the weighted pooled prevalence of anxiety was 26.1% (95% CI 17.9%-36.3%) and the weighted pooled prevalence of depression was 21.4% (95% CI 15.4%-29.0%). Studies identified female gender, past psychiatric history and violent causation as factors associated with anxiety and depression. Limitations Included studies were limited to those published in peer reviewed journals. Longitudinal trends in both anxiety and depression were limited by a short duration of follow up. Conclusions There is a high and persistent burden of affective disorders in patients with facial scars. Additional research is required to further characterise this population and develop effective management strategies.

This paper presents the stress–strain response and general lifetime damage modelling of glass fibre reinforced epoxy (GRE) composite pipes subjected to multi-ratios stress loadings at room temperature (RT). This particular modelling work was developed to predict the non-linear stress– strain response caused by the fatigue static and cyclic loading in the multiaxial ultimate elastic wall stress (UEWS) tests by considering the effects of matrix cracking within the laminates. Although the UEWS procedure is not a standard protocol used for qualification of GRE pipes, it appears to offer an option to existing procedures delineated in ASTM D2992. The ply properties initially expressed as a function of crack density was computed as a function of increasing stress and strain using shear lag approximation. In general lifetime damage model, the effects of stress developed in each ply from ultimate elastic wall stress (UEWS) test were expressed in a single quadratic term of axial and hoop stress. The term then solved to produce limits with respect to axial and hoop stress, which represented in a graphical form of failure envelope. The predictions from both models are found to be in good agreement with the data from the multiaxial UEWS tests of i55u filament wound GRE pipes. These models thus enable for the long term performance prediction of the pipes under combined loadings.

This paper describes the acoustic emission (AE) monitoring of multiaxial ultimate elastic wall stress (UEWS) tests of filament wound glass fibre-reinforced epoxy composite pipes under hydrostatic, pure axial and pure hoop loadings at room temperature. The purpose of AE monitoring is to quantitatively identify and characterise damage inception and evolution, which leading to different failure mechanisms via an analysis of AE parameters. AE parameters such as counts and energy released were plotted against time, and changes of these AE activities were monitored. A 3D correlation plot between AE amplitude and duration against time for each loading condition was produced and analysed. The AE measurement of both hydrostatic and pure axial loading suggested that matrix cracks were initiated early in the tests and possible had progressed into delamination failure just before UEWS point was reached at 200 MPa of hoop stress and 63 MPa of axial stress, respectively. No clear damage initiation and progression was o...

This paper presents the modelling of a general lifetime performance for glass fibre reinforced epoxy (GRE) composite pipes similar to the well-known Tsai-Hill interactive failure criterion. Tsai Hill criterion is based on the Von Misses distortional energy criterion which was modified to satisfy the orthotropic nature of GRE composite pipes. The effects of stress developed in each ply from ultimate elastic wall stress (UEWS) test were expressed in a single quadratic term of axial and hoop stress through laminate theory. The term then solved to produce limits with respect to axial and hoop stress, which represented in a graphical form of failure envelope. The modelled envelop shows a good agreement with experimental data from the multiaxial UEWS test of ±55° GRE composite pipes. This indicates that such model can be used to predict the long-term performance of GRE pipes under combine loadings.

One of the typical failure modes of composite repairs in oil and gas pipelines is the formation of a blister underneath the repair. Exceeding the critical pressure, and therefore the critical energy release rate ( GC) for crack propagation, will result in failure of the repair. Knowing the magnitude of the energy release rate ( G) is therefore key to understanding the interfacial debonding between a steel pipe and a composite repair. This paper describes two approaches for calculating the value of G for crack advance: (a) a purely analytical evaluation and (b) finite element analysis computation using the pressure–volume method (PVM). The design guidance by ASME and ISO standards for correct dimensioning is also presented, incorporating the most recent changes, which are derived from the work presented here.

This paper describes the modeling of multiaxial ultimate elastic wall stress (UEWS) at room temperature for glass fibre reinforced epoxy (GRE) composite pipes. The model developed, predicts the stress-strain response caused by the combined, static and cyclic of UEWS loading taking into effects of transverse matrix cracking within the laminates. The procedure, although not a standard method, seems to provide a good alternative to the current raw materials' re-qualification procedure delineated in ISO 14692 through ASTM D2992. The effective transverse and shear modulus of the lamina due to increasing presence of transverse matrix cracking were estimated. Classical laminate analysis was then applied to compute the corresponding ply properties as a function of increasing stress and strain. The model shows a good agreement with the experimental results of multiaxial UEWS tests on ±55° filament wound glass-reinforced epoxy pipes.

This article presents an experimental study of fusion-bonded polypropylene (PP) glass composite joints in the context of small craft manufacture. The objective is to investigate the manufacturing of lap joints and T-joints as a structural part of a small boat and study their properties, because a joining technique is a fundamental requirement of any boat construction technology. Results show that PP interlayers improve bond quality for both lap joints and T-joints and that woven precursor materials are preferred for T-joint manufacturing. It was also found that this technique produces higher lap shear strength values than adhesives and resistance welding, and that pull-out strength values were comparable with those of thermosetting designs, demonstrating that fusion bonding is a suitable joining technique for thermoplastic composite craft.

This paper presents an experimental investigation of the behaviour of filament wound glass fibre reinforced epoxy (GRE) composite pipe under hydrostatic and biaxial load conditions at temperatures up to 95 °C. The format of the experiments has been chosen to be compatible with the Future Pipe Industries (FPI) procedure using the ultimate elastic wall stress (UEWS) concept in the qualification and production control of GRE. The test appears to provide an attractive alternative to the current 1000 hour test procedure detailed in ASTM D2992 for the detection of manufacturing changes and reconfirmation of the design basis of the pipe. Six different stress ratios ranging from pure axial loading 0:1, 0.5:1, 1:1, 2:1, 4:1 and pure hoop 1:0 loading were tested. Three distinct failure modes were observed: tensile axial failure at pure axial loading, weepage at axial dominated loading from 0.5:1 to 2:1 and localized leakage failure under hoop dominated loading of 4:1 and 1:0. Full tensile–tensile UEWS and leakage based failure envelopes have been developed at a range of temperatures from 20 °C (RT) to 95 °C. Both showed a strong dependence on stress ratio and test temperatures. It was also shown that the UEWS based failure envelope at elevated temperatures generally degraded, except for the 2:1 loading where the UEWS strength increased.

Procedures for qualifying fibreglass pipes are discussed here in relation to industry needs. The ultimate elastic wall stress (UEWS) test appears to provide an efficient means of rating pressure pipe, and indeed vessels, for the case where weepage failure occurs resulting from the accumulation of matrix cracks. The principle behind the UEWS test is to identify, from the pressure–strain response, a pressure level below which damage growth is either negligible or at least sufficiently low to avoid failure within the design life. The version of the UEWS test most often used involves the application of groups of 10 one-minute pressure cycles at increasing pressure values, recording the hoop or axial strain. The onset of non-linearity in the pressure–strain relationship can be accurately determined and enables a safe long term pressure level to be identified. The UEWS test appears to provide a desirable alternative to the currently used procedure laid down in ISO 14692, which involves an expensive series of long term constant pressure tests, as described in ASTM 2992, running for a period in excess of 10 000 h. It is shown here that the UEWS test reflects the cyclic fatigue behaviour of fibreglass pipe, but further work on the relationship between cyclic and static behaviour would be desirable. It has been shown that a Miner’s law approach is effective in modelling damage due to combined static and cyclic effects, and that damage can be directly related to matrix crack growth. This approach could form the basis of a future procedure for describing lifetime behaviour of glass reinforced epoxy pipes under any required combination of static, fatigue, hydrostatic and non-hydrostatic (multiaxial) loading.

The effect of heat and fire on the mechanical properties and failure of polymer composite materials used in naval ship structures is investigated. Coupled thermal-mechanical models are presented for predicting the loss in strength and failure of load-bearing polymer laminates when heated from one-side. The thermal component of the models predicts the temperature and decomposition rate of a laminate. Using this information, several mechanical models based on progressive softening analysis or laminate analysis can be used to predict the reduction in strength and time-to-failure. A coupled thermal-mechanical model that is solved using finite element analysis is also presented. Experimental fire-under-load tests are performed on several types of polymer laminate materials to evaluate the accuracy of the models. The tests were performed at different heat flux levels between 10 kW/m2 and 75 kW/m2, which is equivalent to surface temperatures between about 250°C and 700°C. The temperature, mass loss and char formation of a laminate can be accurately predicted for a wide range of thermal conditions using the models. The models can also predict the time-to-failure of laminates under static tension or compression loading. The models presented in this chapter are considered useful analytical tools for naval architects to estimate the loss in mechanical performance and time-to-failure of composite ship materials in fire.

A coupled thermo-mechanical model is presented for calculating the compressive strength and failure of polymer laminated composites with thermal barrier when exposed to fire. Thermal barriers are used to protect composite structures from fire, and this article presents a model for calculating the improved structural survivability under compression loading. The thermal component of the model predicts the through-thickness temperature profile of the composite when protected from fire using a passive thermal barrier insulation material. The thermal analysis is coupled to a mechanical model that calculates the loss in compressive strength with increasing temperature and heating time. The model predicts the strength loss and failure time of an insulated composite supporting a static compressive load when exposed to fire. The accuracy of the model is evaluated using failure times measured in fire-under-compression load tests on a woven E-glass/vinyl ester composite protected with a passive thermal barrier. The model predicts reductions to the failure time with increasing heat flux (temperature), applied compressive stress, and reduced insulation thickness, and this is confirmed by experimental testing. It is envisaged that the thermo-mechanical model is a useful analytical method to design thermal barrier material systems to protect composite structures exposed to high temperature or fire.

The delivery of the power from remote power generation sites to urban centres is increasingly becoming a challenge for the power industry since the use of traditional power transmission technology, such as overhead cables, is a politically sensitive issue and alternative approaches are sought. This paper reports the findings of a feasibility study into long distance power transmission via small diameter underground tunnels, constructed using trenchless technologies such as horizontal directional drilling or microtunnelling. The study examines the suitability of AC or DC transmission for such underground tunnels, various cooling methods to remove the heat generated in the conductors from electrical losses, type of conductor to be used, and issues concerning conductor installation. As a result of this study a number of technical challenges have been identified that need to be overcome in order to make the method an economically and technically viable option.

The composites have wide range of applications in different fields especially in offshore oil and gas industry, where it was used in the areas of pipe works and structural applications. The awareness of utilizing the composite material is still not deployed successfully in the above said fields. Hence an attempt was made to review the effective usage of composite materials in the field of offshore industry and its applications. It was noticed that further improvements in the field of deepwater construction using composite materials is necessary for the betterment of the offshore industry. The challenges for the future in offshore industry will be from shallow to deepwater construction and a probable change of emphasis from topside to subsea application. These challenges bring with them the possibility of greatly increased markets for both glass fiber-based and high-performance composites. Moreover, the development of functional graded composite material is essential for the suitable application and its effective usage. It is concluded that the further research in the field of composite material for the betterment of the offshore industry should be carried out with advanced smart materials.

This paper presents a model for the stiffness terms of composite sandwich panels with structured cores (referred to as ‘z-core’ panels). Truss-cores, corrugated-cores and double-corrugated cores containing a polymeric foam were considered. The model was validated, both through finite element simulation and through comparison with the results of experimental three point bend tests on panels. A parametric study was performed to assess the performance of the different reinforced panel configurations.

Composite repairs are emerging as a viable and often preferred alternative to metallic repairs in the oil and gas industry. The use of composite presents key advantages over metal, including reduced weight, smaller relative density with water and greater corrosion resistance. This chapter reviews current and emerging methods for composite repairs of pipelines, along with repair codes, and presents in-depth discussions on two different repair solutions: clamp and overwrap. It is shown that these composite repairs allow rehabilitation of wall thinning and through-wall damage above water, in the splash zone and subsea, over a range of conditions.

This paper relates to the ‘netting–analysis’ approach, often used in calculations of the behaviour of helically wound reinforced pressure vessels and tubes. Numerical calculation of the stress–strain relations for angle ply composite laminates often gives the impression of unexpected instability in the underlying equations. For instance, when the in–plane principal stresses are in the ratio 2:1 and the fibres are inclined at an angle close to θ ± arctan 2, the stress–strain relations are very sensitive to the value of θ and to the relative stiffness of the fibres and matrix. There is a simple explanation for this, which is most clearly understood by developing analytical approximations for the stress–strain relations. It is shown that the stable angle of inclination of the fibres, where no strain–induced fibre rotations occur, deviates from the so–called ‘ideal’ fibre angle predicted by netting analysis by an amount that depends on the matrix–to–reinforcement–stiffness ratio. When the initial angle of inclination of the fibres deviates from the stable angle, the application of strain produces fibre rotation and nonlinear stress–strain relations result. Analytical expressions for the stress–strain relations have been obtained; they show the interaction of the parameters that control the shape of the stress–strain curves.

The structural performance of a symmetric steel to composite bonded joint has been examined. Numerical predictions and experimental results on the mechanical strength of the joint are presented. The experimental data and the findings from this study provide useful guidelines to ship designers for using large composite structural components in steel ships.

Summary Background Ataxia is the commonest neurological manifestation of coeliac disease. Some individuals with genetic susceptibility to the disease have serological evidence of gluten sensitivity without overt gastrointestinal symptoms or evidence of small-bowel inflammation. The sole manifestation of disease in such patients may be ataxia. We describe the clinical, radiological, and neurophysiological features of this disorder. Methods Patients with ataxia attending the neurology outpatient clinics at the Royal Hallamshire Hospital, Sheffield, UK, were screened for gluten sensitivity as shown by the titre of antibody to gliadin. Those with other causes of ataxia were excluded. We carried out clinical, neurophysiological, neuroradiological, and, in two cases, neuropathological examinations. Findings 28 patients with gluten ataxia were identified. All had gait ataxia and most had limb ataxia. Those with more severe gait ataxia had longer disease duration. No patient had tremor or other extrapyramidal features. 19 patients showed some form of peripheral neuropathy on neurophysiological examination. 16 patients had no gastrointestinal symptoms. Distal duodenal biopsy showed lymphocytic infiltration in two patients, and changes compatible with coeliac disease in 11. Six patients had evidence of cerebellar atrophy on magnetic-resonance imaging. Necropsy was done on two patients who died; there was lymphocytic infiltration of the cerebellum, damage to the posterior columns of the spinal cord, and sparse infiltration of the peripheral nerves. Interpretation Gluten sensitivity is an important cause of apparently idiopathic ataxia and may be progressive. The ataxia is a result of immunological damage to the cerebellum, to the posterior columns of the spinal cord, and to peripheral nerves. We propose the term gluten ataxia to describe this disorder.

The paper describes low-velocity impact tests on square panels made from two polymer composite sandwich constructions, namely woven glass vinyl ester skins with Coremat core and woven glass epoxy pre-preg skins with honeycomb core. The impact velocity was up to 8 m s -1 with an impact mass of up to 30 kg giving a maximum impact energy of 882 J. This maximum energy gives full perforation of the panels. The panels were 0.5 m by 0.5 m with clamped but free to pull in boundary conditions. The impactor geometry considered was a 50 mm diameter hemisphere. Results are expressed in the form of energy and failure mode plots and it is shown that the energy absorbing capabilities of the panels increase with the velocity of impact. The increase in energy absorption is attributed to an increase in the core crush stress and skin failure stress at high strain rates. Some discussion is given on the influence of the energy absorbing capabilities of constituent materials on the overall energy absorption behaviour of the panel. Suggestions have also been made for increasing panel perforation energy.

Objectives—To describe the range of neuromuscular disorders which may be associated with cryptic coeliac disease. Methods—Nine patients were described with neuromuscular disorders associated with circulating antigliadin antibodies, whose duodenal biopsies later confirmed the diagnosis of coeliac disease. Neurological symptoms antedated the diagnosis of coeliac disease in all, and most had minimal or no gastrointestinal symptoms at the onset of the neuromuscular disorder. Results—Three patients had sensorimotor axonal peripheral neuropathy, one had axonal motor peripheral neuropathy, one had probable inclusion body myositis and axonal motor peripheral neuropathy, one had polymyositis and sensorimotor peripheral neuropathy, one had mononeuropathy multiplex,one had neuromyotonia, and one had polyneuropathy. Conclusion—A wide range of neuromuscular disease may be the presenting feature of coeliac disease. This represents the first report of inclusion body myositis and neuromyotonia associated with coeliac disease. Estimation of circulating antigliadin antibodies should be considered in all patients with neuromuscular disease of otherwise obscure aetiology. (J Neurol Neurosurg Psychiatry 1997;63:770‐775)

External pressure tests on two 0·8 m diameter torispherical domed ends made from woven roving carbon fibre reinforced plastic (CFRP) pre-preg are discussed in the paper. The domes were made from 20 and 30 plies, respectively. The BOSOR 4 program was used to predict the stresses in the shells and their buckling pressures; the Tsai-Wu equation (in stress space) was adopted for the material failure criterion. In the test on the 20-ply dome, the first cracking noises occurred simultaneously with the collapse of the dome. The predicated first ply failure (FPF) pressure differed by about 10% from the experimental collapse pressure and was about two-thirds the theoretical buckling pressure of the dome (assumed to be perfect). The actual 20-ply dome had a slight flattening at its apex but, when this was incorporated into the buckling analyis, it had no effect on the theoretical buckling pressure. For the 30-ply dome, the FPF pressure again differed by about 10% from the experimental collapse pressure and was less than 60% of the theoretical buckling pressure. However, in this case, the first cracking noises were heard at a pressure which was about one-half the experimental collapse pressure. Between the two pressures, many cracking noises were heard. The test pressures at which first cracking was heard were not very different for the 20-ply and the 30-ply domes. However, the reason of the ‘first cracking’ pressure for the 30-ply being so much lower than its FPF pressure is not known at the moment. It is clear that, if CFRP domes are to be used in deep submersibles, then the ‘first cracking’ pressure for the 30-ply dome will have to be increased considerably. Changing the stacking sequence, the fabrication process or the shape of the dome might bring this about.

Summary Background Antigliadin antibodies are a marker of untreated coeliac disease but can also be found in individuals with normal small-bowel mucosa. Because neurological dysfunction is a known complication of coeliac disease we have investigated the frequency of antigliadin antibodies, as a measure of cryptic gluten sensitivity, and coeliac disease in neurological patients. Methods Using ELISA, we estimated serum IgG and IgA antigliadin antibodies in 147 neurological patients who were divided into two groups. There were 53 patients with neurological dysfunction of unknown cause despite full investigation (25 ataxia, 20 peripheral neuropathy, 5 mononeuritis multiplex, 4 myopathy, 3 motor neuropathy, 2 myelopathy). The remaining 94 patients were found to have a specific neurological diagnosis (16 stroke, 12 multiple sclerosis, 10 Parkinson's disease, 56 other diagnoses) and formed the neurological control group. 50 healthy blood donors formed a third group. Findings The proportions of individuals with positive titres for antigliadin antibodies in the three groups were 30/53, 5/94, and 6/50 respectively (57, 5, and 12%). The difference in proportion between group 1 and the combined control groups was 0·49 (95% Cl 0·35-0·63). Distal duodenal biopsies in 26 out of 30 antigliadin-positive patients from group 1 revealed histological evidence of coeliac disease in nine (35%), non-specific duodenitis in ten (38%), and no lesion in seven (26%) individuals. Interpretation Our data suggest that gluten sensitivity is common in patients with neurological disease of unknown cause and may have aetiological significance.

SUMMARY The aerobic bacterial flora of 20 patients with atopic dermatitis and 19 control subjects was extensively sampled using the Williamson and Kligman scrub technique and a contact-plate method (cysteine lactose electrolyte deficient media). Comparison of the two quantitative techniques showed that the contact plate is a reliable and convenient alternative to the scrub technique for the quantification of Staphylococcus aureus, micrococci and coagulase negative staphylococci. Quantification of bacterial flora using both techniques showed high rates of colonization by S. aureus on both involved and clinically normal skin of patients with atopic dermatitis. A linear increase in S. aureus counts with increasing severity of dermatitis was found. In contrast, diphtheroids showed a trend of decreasing isolation rates and counts as the severity of the dermatitis increased. Isolation rates and absolute counts for micrococci/coagulase negative cocci were unaffected by the severity of the dermatitis.

The embryo, as represented by the model, is bent upon itself, at the level of the cranial border of its umbilical orifice—that is, at the caudal end of the pericardial region; and, as a result of the bending, the general outline of the embryo, when viewed from the side, is hook-shaped.The dorsal and longer limb of the hook is formed by the more caudal portion of the embryo—that is, the part which would lie caudal to the cranial margin of the umbilicus if the embryo were unbent.

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