Prototyping and load testing of thin-shell concrete floors

Buildings are being constructed at ever faster rates, fuelled by population growth and urbanisation. The total worldwide floor area of buildings is expected to almost double over the next 40 years, the equivalent of constructing Paris every five days. The majority of the mass and embodied energy (60% to 70%) in a typical multi-storey building structure exists within the floors, making these a primary target for sustainable structural design. In a typical reinforced concrete slab, much of the concrete is assumed to be cracked and therefore not structurally utilised, but nevertheless adds significant weight. This project proposes a radical re-design of concrete floors, using precast textile-reinforced concrete shells with an in-situ foamed concrete fill. By harnessing membrane action, self-weight savings of 62% have been demonstrated for typical spans (compared to traditional flat slabs). This paper discusses the design, optimisation, construction, measurement, analysis and structural testing of two prototype shells, one with and one without foamed concrete fill. The construction accuracy was quantified using digital scanner measurements which were then used as a geometry input for the analysis model. Each shell was loaded both uniformly and asymmetrically to beyond the design loading before failure. The foamed concrete was found to provide only a small increase in strength and stiffness. A design methodology for full-scale, practical application is currently under development.Building Research Establishment (BRE) Trust Cambridge University Department of Engineerin

Development and evaluation of a diagnostic cytokine-release assay for Mycobacterium suricattae infection in meerkats (Suricata suricatta)

CITATION: Clarke, C., et al. 2017. Development and evaluation of a diagnostic cytokine-release assay for mycobacterium suricattae infection in meerkats (Suricata suricatta). BMC Veterinary Research, 13:2, doi:10.1186/s12917-016-0927-x.The original publication is available at http://bmcvetres.biomedcentral.comBackground: Sensitive diagnostic tools are necessary for the detection of Mycobacterium suricattae infection in meerkats (Suricata suricatta) in order to more clearly understand the epidemiology of tuberculosis and the ecological consequences of the disease in this species. We therefore aimed to develop a cytokine release assay to measure antigen-specific cell-mediated immune responses of meerkats. Results: Enzyme-linked immunosorbent assays (ELISAs) were evaluated for the detection of interferon-gamma (IFN-γ) and IFN-γ inducible protein 10 (IP-10) in meerkat plasma. An IP-10 ELISA was selected to measure the release of this cytokine in whole blood in response to Bovigam® PC-HP Stimulating Antigen, a commercial peptide pool of M. bovis antigens. Using this protocol, captive meerkats with no known M. suricattae exposure (n = 10) were tested and results were used to define a diagnostic cut off value (mean plus 2 standard deviations). This IP-10 release assay (IPRA) was then evaluated in free-living meerkats with known M. suricattae exposure, categorized as having either a low, moderate or high risk of infection with this pathogen. In each category, respectively, 24.7%, 27.3% and 82.4% of animals tested IPRA-positive. The odds of an animal testing positive was 14.0 times greater for animals with a high risk of M. suricattae infection compared to animals with a low risk. Conclusion: These results support the use of this assay as a measure of M. suricattae exposure in meerkat populations. Ongoing longitudinal studies aim to evaluate the value of the IPRA as a diagnostic test of M. suricattae infection in individual animals.http://bmcvetres.biomedcentral.com/articles/10.1186/s12917-016-0927-xPublisher's versio

The Changing Face of Youth Employment in Europe

This article examines trends in youth employment across the EU-15 countries during 2002-6 and 2007-11. Drawing upon microdata from the EU-Labour Force Survey it examines changes in contract-type, hours worked and occupation by level of education. Although the financial crisis creates a discontinuity in numbers employed, and despite certain country specificities, we observe common structural changes across the two periods. We find an increasing shift from permanent full-time to temporary part-time contracts, the ‘hollowing out’ of traditional mid-skill level occupations and evidence of ‘occupational filtering down’ whereby the higher-educated are substituted for the lower-educated in low-skilled occupations. We observe some growth in ‘professionals’ following the crisis, but little evidence of the rise of a new knowledge economy. This raises questions concerning the most appropriate policy approaches to education and training and labour market regulation if European nations are to provide high-quality employment opportunities for their young people

A strong sense of coherence associated with reduced risk of anxiety disorder among women in disadvantaged circumstances: British population study.

OBJECTIVE: Many patients receiving medical treatment for anxiety relapse or do not improve. Research has therefore been turning to coping mechanisms as a way to decrease anxiety rates. Previously, we showed that living in a deprived area significantly increases the risk of anxiety in women, but not in men. The objective of this study is to assess whether sense of coherence (coping mechanism) buffers the influence of area deprivation on women's risk of generalised anxiety disorder using data from the European Prospective Investigation of Cancer-Norfolk. DESIGN: Large, population study. SETTING: UK population-based cohort. PARTICIPANTS: 30 445 people over the age of 40 years were recruited through general practice registers in England. Of these, 20 919 completed a structured health and lifestyle questionnaire used to assess generalised anxiety disorder and sense of coherence. Area deprivation was measured using 1991 Census data, and sense of coherence and anxiety were examined in 1996-2000. 10 183 women had data on all variables. MAIN OUTCOME MEASURE: Past-year generalised anxiety disorder defined according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. RESULTS: In this study, 2.6% (260/10 183) of women had generalised anxiety disorder. In those with a strong sense of coherence, area deprivation was not significantly associated with anxiety (OR 1.29, 95% CI 0.77 to 2.17). However, among women with a weak sense of coherence, those living in deprived areas were almost twice as likely to have generalised anxiety disorder compared with those living in more affluent areas (OR 1.99, 95% CI 1.37 to 2.91). CONCLUSION: The number of women living in deprived conditions is large worldwide, and significant numbers are affected by generalised anxiety disorder. Sense of coherence moderates the association between area deprivation and anxiety in women; therefore, interventions targeting coping mechanisms may need to be considered for people with anxiety

VE-cadherin and claudin-5: it takes two to tango

Endothelial barrier function requires the adhesive activity of VE-cadherin and claudin-5, which are key components of adherens and tight endothelial junctions, respectively. Emerging evidence suggests that VE-cadherin controls claudin-5 expression by preventing the nuclear accumulation of FoxO1 and -catenin, which repress the claudin-5 promoter. This indicates that a crosstalk mechanism operates between these junctional structures

Sleep duration and risk of fatal and nonfatal stroke: a prospective study and meta-analysis.

OBJECTIVE: To study the association between sleep duration and stroke incidence in a British population and to synthesize our findings with published results through a meta-analysis. METHODS: The prospective study included 9,692 stroke-free participants aged 42-81 years from the European Prospective Investigation into Cancer-Norfolk cohort. Participants reported sleep duration in 1998-2000 and 2002-2004, and all stroke cases were recorded until March 31, 2009. For the meta-analysis, we searched Ovid Medline, EMBASE, and the Cochrane Library for prospective studies published until May 2014, and pooled effect estimates using a weighted random-effect model. RESULTS: After 9.5 years of follow-up, 346 cases of stroke occurred. Long sleep was significantly associated with an increased risk of stroke (hazard ratio [HR] = 1.46 [95% confidence interval (CI) 1.08, 1.98]) after adjustment for all covariates. The association remained robust among those without preexisting diseases and those who reported sleeping well. The association for short sleep was smaller (and not statistically significant) (HR = 1.18 [95% CI 0.91, 1.53]). There was a higher stroke risk among those who reported persistently long sleep or a substantial increase in sleep duration over time, compared to those reporting persistently average sleep. These were compatible with the pooled HRs from an updated meta-analysis, which were 1.15 (1.07, 1.24) and 1.45 (1.30, 1.62) for short and long sleep duration, respectively. CONCLUSIONS: This prospective study and meta-analysis identified prolonged sleep as a potentially useful marker of increased future stroke risk in an apparently healthy aging population.The design and conduct of the EPIC-Norfolk study was supported by program grants from the Medical Research Council of the United Kingdom (grants G9502233 and G1000143) and Cancer Research UK (grants SP2024/0204 and C864/A14136). Ms. Leng is supported by Cambridge Commonwealth, European & International Trusts. Prof. Cappuccio leads the Sleep Health & Society Programme at the University of Warwick supported, in part, by the University of Warwick RDF and IAS. It has received funding by the NHS National Workforce Projects and the Economic & Social Research Council (ES/K002910/1).This is the final published version. It first appeared at http://www.neurology.org/content/early/2015/02/25/WNL.0000000000001371.short

Daytime napping and increased risk of incident respiratory diseases: symptom, marker, or risk factor?

BACKGROUND: We have identified a strong association between daytime napping and increased mortality risk from respiratory diseases, but little is known about the relationship between daytime napping and respiratory morbidity. METHODS: Data were drawn from the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort. Participants reported napping habits during 1998-2000 and were followed up for respiratory disease hospital admissions until March 2009. Cox proportional hazards regression was used to examine the association between daytime napping and respiratory disease incidence risk. RESULTS: The study sample included 10,978 men and women with a mean age of 61.9 years, and a total of 946 incident respiratory disease cases were recorded. After adjustment for age, sex, social class, education, marital status, employment status, nightshift work, body mass index, physical activity, smoking, alcohol intake, self-reported general health, hypnotic drug use, habitual sleep duration, and preexisting health conditions, daytime napping was associated with an increase in the overall respiratory disease incidence risk (hazard ratio (HR) = 1.32, 95% confidence interval (CI) 1.15, 1.52 for napping <1 h; HR = 1.54, 95% CI 1.14, 2.09 for napping ≥1 h). This association was more pronounced for lower respiratory diseases, especially for the risk of chronic lower respiratory diseases (HR = 1.52, 95% CI: 1.18, 1.96 for napping <1 h; HR = 1.72, 95% CI: 1.01, 2.92 for napping ≥1 h, overall p = 0.003). CONCLUSIONS: Excessive daytime napping might be a useful marker of future respiratory disease incidence risk. Further studies are required to confirm these findings and help understand potential mechanisms.Medical Research Council (Grant IDs: G9502233, G1000143); Cancer Research UK (Grant IDs: SP2024/0204, C864/A14136)This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.sleep.2016.06.01

The removal of thermally aged films of triacylglycerides by surfactant solutions

Thermal ageing of triacylglycerides (TAG) at high temperatures produces films which resist removal using aqueous surfactant solutions. We used a mass loss method to investigate the removal of thermally aged TAG films from hard surfaces using aqueous solutions of surfactants of different charge types. It was found that cationic surfactants are most effective at high pH, whereas anionics are most effective at low pH and a non-ionic surfactant is most effective at intermediate pH. We showed that the TAG film removal process occurs in several stages. In the first ‘‘lag phase’’ no TAG removal occurs; the surfactant first partitions into the thermally aged film. In the second stage, the TAG film containing surfactant was removed by solubilisation into micelles in the aqueous solution. The effects of pH and surfactant charge on the TAG removal process correlate with the effects of these variables on the extent of surfactant partitioning to the TAG film and on the maximum extent of TAG solubilisation within the micelles. Additionally, we showed how the TAG removal is enhanced by the addition of amphiphilic additives such as alcohols which act as co-surfactants. The study demonstrates that aqueous surfactant solutions provide a viable and more benign alternative to current methods for the removal of thermally aged TAG films

Daytime napping, sleep duration and serum C reactive protein: a population-based cohort study.

OBJECTIVES: To explore whether daytime napping and sleep duration are linked to serum C reactive protein (CRP), a pro-inflammatory marker, in an older aged British population. DESIGN: Cross-sectional study. SETTING: European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study. PARTICIPANTS: A total of 5018 men and women aged 48-92 years reported their sleep habits and had serum CRP levels measured. OUTCOME AND MEASURES: CRP was measured (mg/L) during 2006-2011 in fresh blood samples using high-sensitivity methods. Participants reported napping habits during 2002-2004, and reported sleep quantity during 2006-2007. Multivariable linear regression models were used to examine the association between napping and log-transformed CRP, and geometric mean CRP levels were calculated. RESULTS: After adjustment for age and sex, those who reported napping had 10% higher CRP levels compared with those not napping. The association was attenuated but remained borderline significant (β=0.05 (95% CI 0.00 to 0.10)) after further adjustment for social class, education, marital status, body mass index, physical activity, smoking, alcohol intake, self-reported health, pre-existing diseases, systolic blood pressure, hypnotic drug use, depression and in women-only hormone replacement therapy use. The geometric means (95% CI) of CRP levels were 2.38 (2.29 to 2.47) mg/L and 2.26 (2.21 to 2.32) mg/L for those who reported napping and no napping, respectively. A U-shaped association was observed between time spent in bed at night and CRP levels, and nighttime sleep duration was not associated with serum CRP levels. The association between napping and CRP was stronger for older participants, and among extremes of time spent in bed at night. CONCLUSIONS: Daytime napping was associated with increased CRP levels in an older aged British population. Further studies are needed to determine whether daytime napping is a cause for systemic inflammation, or if it is a symptom or consequence of underlying health problems.The design and conduct of the EPIC-Norfolk study and collection and management of the data was supported by programme grants from the Medical Research Council UK (G9502233, G0300128) and Cancer Research UK (C865/A2883). YL is supported by the Cambridge Overseas Trust. FPC leads the Sleep Health & Society Programme at the University of Warwick supported, in part, by the University of Warwick RDF and IAS. It has received funding by the NHS National Workforce Projects and the Economic & Social Research Council (ES/K002910/1).This is the final version. It was first published by BMJ Group at http://bmjopen.bmj.com/content/4/11/e006071.full

Daytime napping and the risk of all-cause and cause-specific mortality: a 13-year follow-up of a British population.

Epidemiologic studies have reported conflicting results on the relationship between daytime napping and mortality risk, and there are few data on the potential association in the British population. We investigated the associations between daytime napping and all-cause or cause-specific mortality in the European Prospective Investigation Into Cancer-Norfolk study, a British population-based cohort study. Among the 16,374 men and women who answered questions on napping habits between 1998 and 2000, a total of 3,251 died during the 13-year follow-up. Daytime napping was associated with an increased risk of all-cause mortality (for napping less than 1 hour per day on average, hazard ratio = 1.14, 95% confidence interval: 1.02, 1.27; for napping 1 hour or longer per day on average, hazard ratio = 1.32, 95% confidence interval: 1.04, 1.68), independent of age, sex, social class, educational level, marital status, employment status, body mass index, physical activity level, smoking status, alcohol intake, depression, self-reported general health, use of hypnotic drugs or other medications, time spent in bed at night, and presence of preexisting health conditions. This association was more pronounced for death from respiratory diseases (for napping less than 1 hour, hazard ratio = 1.40, 95% confidence interval: 0.95, 2.05; for napping 1 hour or more, hazard ratio = 2.56, 95% confidence interval: 1.34, 4.86) and in individuals 65 years of age or younger. Excessive daytime napping might be a useful marker of underlying health risk, particularly of respiratory problems, especially among those 65 years of age or younger. Further research is required to clarify the nature of the observed association.The funding sources did not have a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript