457 research outputs found

    Comparative study of the effect of fuel deoxygenation and polar species removal on jet fuel surface deposition

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    The effect of near-complete deoxygenation and polar species removal on deposition propensity of a Jet A-1 fuel type, with marginal thermal oxidative stability was studied in a laboratory scale approach. The fuel deoxygenation was carried out via nitrogen purging and two types of bespoke zeolites were used separately in a packed bed reactor for partial polar separation. The treated fuel samples were assessed individually for deposition propensity, using “High Reynolds Thermal Stability(HiReTS)” test device. It was found that when the concentration of hydroperoxides in fuel is relatively high, polar removal is more effective way than the fuel deoxygenation in reducing carbona- ceous deposits. Furthermore, competitive adsorption of dissolved O 2 with polar species was studied for a model fuel doped with a few polar species, as well as for the Jet A-1 with marginal thermal stability, in the packed bed reactor with zeolite 3.7Å. The polar species added to the model fuel share the same functional groups as those in Jet A-1 with a strong im pact on fuel thermal degradation and surface deposition. These include hexanoic acids, heaxnol, hexanal, hexanone, phenyl amine (aniline), butylated hydroxytoluene(BHT), dibutyl disulfide and Fe naphthenate. A one-dimensional model for calculation of dissolved O 2 adsorption in the packed bed reactor was built using COMSOL Multiphysics. The modelling results were in good agreement with the induction period prior to the beginning of the O 2 adsorption, as well as the different stages of O 2 uptake during the competitive adsorption between dissolved O 2 and polar species in the Jet A-1 fuel. The calculation showed a discrep- ancy with the experimental results beyond the second phase of O 2 adsorption. More theories, assumptions and physical sub-models are required to build a more robust pre- dictive model. A new chemical reaction pathway based on the self-reaction of hydroperoxides was proposed as part of “Basic Autoxidation Scheme(BAS)” to justify the relatively high deposition propensity of the marginal fuel after near-complete deoxygenation. The vi- ability of this reaction pathway was supported by the quantum chemistry calculations

    Public Health and Obesity in England - the New Infrastructure Examined

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    Clinical management of nausea and vomiting in pregnancy and hyperemesis gravidarum across primary and secondary care: a population based study

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    Objectives: To assess how nausea and vomiting in pregnancy (NVP) and hyperemesis gravidarum (HG) are managed and treated across primary and secondary care.Design: Population-based pregnancy cohortSetting: Medical records (CPRD-GOLD) from EnglandPopulation: 417,028 pregnancies, during 1998-2014 Methods: Proportions of pregnancies with recorded NVP/HG diagnoses, primary care treatment and hospital admissions were calculated. Multinomial logistic regression was employed to estimate adjusted relative risk ratios (aRRRs) with 99% confidence intervals (CIs) for the association between NVP/HG management paths and maternal characteristics.Main Outcome Measures: NVP/HG diagnoses, treatments and hospital admissions. Results: Overall prevalence of clinically recorded NVP/HG was 9.1%: 2.1% had hospital admissions, 3.4% were treated with antiemetics in primary care only, and 3.6% had only recorded diagnoses. Hospital admissions and antiemetic prescribing increased continuously during 1998-2013 (trend p less than 0.001). Younger age, deprivation, Black/Asian/Mixed ethnicity, multiple-pregnancy were associated with NVP/HG generally across all levels, but associations were strongest for hospital admissions. Most comorbidities had patterns of association with NVP/HG levels. Among women with NVP/HG who had no hospital admissions, 49% were prescribed antiemetics, mainly from first line treatment (21% prochlorperazine, 15% promethazine, 13% cyclizine) and metoclopramide (10%). Of those admitted, 38% had prior antiemetic prescriptions (34% first-line, 9% second-line, 1% third-line treatment).Conclusion: Previous focus on hospital admissions has greatly underestimated the NVP/HG burden. Although primary care prescribing has increased, most women admitted to hospital have no antiemetics prescribed before this. An urgent call is made to assess whether admissions could be prevented with better primary care recognition and timely treatment

    Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices

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    The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people

    Exploring the biochemistry at the extracellular redox frontier of bacterial mineral Fe(III) respiration

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    Many species of the bacterial Shewanella genus are notable for their ability to respire in anoxic environments utilizing insoluble minerals of Fe(III) and Mn(IV) as extracellular electron acceptors. In Shewanella oneidensis, the process is dependent on the decahaem electron-transport proteins that lie at the extracellular face of the outer membrane where they can contact the insoluble mineral substrates. These extracellular proteins are charged with electrons provided by an inter-membrane electron-transfer pathway that links the extracellular face of the outer membrane with the inner cytoplasmic membrane and thereby intracellular electron sources. In the present paper, we consider the common structural features of two of these outer-membrane decahaem cytochromes, MtrC and MtrF, and bring this together with biochemical, spectroscopic and voltammetric data to identify common and distinct properties of these prototypical members of different clades of the outer-membrane decahaem cytochrome superfamily

    Impact of a community-based pilot intervention to tackle childhood obesity: a ‘whole-system approach’ case study

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    Background Go-Golborne was a three-year pilot programme to test an innovative, community-based ‘whole system’ approach to preventing overweight in children in Golborne ward, London. Whilst there is a growing interest in local whole systems approaches to obesity, understandings of what they look like in practice are newly emerging. Go-Golborne was designed, implemented and evaluated within this context. Methods The evaluation used a case-study design and theory of change approach to assess the effectiveness of the intervention. Height/weight measurements of children in the six participating primary schools were recorded annually for 4 years. For behavioural outcomes, children aged six-11 completed four annual on-line surveys (total 4331 responses). Parents were surveyed in year one and year four (177 responses). Three focus group discussions were held with children aged 10–11 (N = 21); interviews were conducted with parents (N = 11), and school representatives (N = 4). Stakeholders were surveyed twice (37 responses), and interviews were conducted with key stakeholders (N = 11). An extensive range of programme documents were reviewed and additional process data was collected from the programme team. The RE-AIM framework was used to synthesise findings and examine public health impact. Results Go-Golborne reached a diverse range of partners across Golborne. Events were attended by over 3360 local children and families and all six primary schools in the ward actively engaged in activities. The proportion of children in the above healthy weight categories remained stable over time. A number of changes in home, school and neighbourhood environments to support healthy behaviour change were evidenced. There was some qualitative evidence of positive changes in children’s behaviours, though significant or sustained changes were not evidenced by the quantitative data. Conclusions Go-Golborne helped stakeholders and parents to develop a shared commitment to improving healthy weight in children, to identify barriers to a healthy lifestyle, and to start to make changes in their services/behaviours. The campaigns and changes made at micro-level appeared to be insufficient, in the face of counteracting forces and personal factors, to achieve significant behaviour change within 3 years. This highlights the need for local initiatives to be reinforced by supporting action at regional, national and global levels

    Probing a Complex of Cytochromecand Cardiolipin by Magnetic Circular Dichroism Spectroscopy: Implications for the Initial Events in Apoptosis

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    Oxidation of cardiolipin (CL) by its complex with cytochrome c (cyt c) plays a crucial role in triggering apoptosis. Through a combination of magnetic circular dichroism spectroscopy and potentiometric titrations, we show that both the ferric and ferrous forms of the heme group of a CL:cyt c complex exist as multiple conformers at a physiologically relevant pH of 7.4. For the ferric state, these conformers are His/Lys- and His/OH–-ligated. The ferrous state is predominantly high-spin and, most likely, His/–. Interconversion of the ferric and ferrous conformers is described by a single midpoint potential of -80 ± 9 mV vs SHE. These results suggest that CL oxidation in mitochondria could occur by the reaction of molecular oxygen with the ferrous CL:cyt c complex in addition to the well-described reaction of peroxides with the ferric form

    16S pan-bacterial PCR can accurately identify patients with ventilator-associated pneumonia

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    Ventilator-associated pneumonia (VAP) remains a challenge to intensive care units, with secure diagnosis relying on microbiological cultures that take up to 72 hours to provide a result. We sought to derive and validate a novel, real-time 16S rRNA gene PCR for rapid exclusion of VAP. Bronchoalveolar lavage (BAL) was obtained from two independent cohorts of patients with suspected VAP. Patients were recruited in a 2-centre derivation cohort and a 12-centre confirmation cohort. Confirmed VAP was defined as growth of >104^4 colony forming units/ml on semiquantitative culture and compared with a 16S PCR assay. Samples were tested from 67 patients in the derivation cohort, 10 (15%) of whom had confirmed VAP. Using cycles to cross threshold (Ct_t) values as the result of the 16S PCR test, the area under the receiver operating characteristic (ROC) curve (AUROC) was 0.94 (95% CI 0.86 to 1.0, p<0.0001). Samples from 92 patients were available from the confirmation cohort, 26 (28%) of whom had confirmed VAP. The AUROC for Ct_t in this cohort was 0.89 (95% CI 0.83 to 0.95, p<0.0001). This study has derived and assessed the diagnostic accuracy of a novel application for 16S PCR. This suggests that 16S PCR in BAL could be used as a rapid test in suspected VAP and may allow better stewardship of antibiotics.This study was funded by: the Northern Ireland Health and Social Care Research and Development division; the Hospital Infection Society; the Department of Health and Wellcome Trust through the Health Innovation Challenge (HIC) Fund; and the Sir Jules Thorn Charitable Trust

    The response to and impact of the Ebola epidemic: towards an agenda for interdisciplinary research

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    The 2013-16 Ebola virus disease (EVD) epidemic in West Africa was the largest in history and resulted in a huge public health burden and significant social and economic impact in those countries most affected. Its size, duration and geographical spread presents important opportunities for research than might help national and global health and social care systems to better prepare for and respond to future outbreaks. This paper examines research needs and research priorities from the perspective of those who directly experienced the EVD epidemic in Guinea. Methods: The paper reports the findings from a research scoping exercise conducted in Guinea in 2017. This exercise explored the need for health and social care research, and identified research gaps, from the perspectives of different groups. Interviews were carried out with key stakeholders such as representatives of the Ministry of Health, NGOs, academic and health service researchers and members of research ethics committees (N=15); health practitioners (N=12) and community representatives (N=11). Discussion groups were conducted with male and female EVD survivors (N=24) from two distinct communities. Results: This research scoping exercise identified seven key questions for further research. An important research priority that emerged during this study was the need to carry out a comprehensive analysis of the wider social, economic and political impact of the epidemic on the country, communities and survivors. The social and cultural dynamics of the epidemic and the local, national and international response to it need to be better understood. Many survivors and their relatives continue to experience stigma and social isolation and have a number of complex unmet needs. It is important to understand what sort of support they need, and how that might best be provided. A better understanding of the virus and the long-term health and social implications for survivors and non-infected survivors is also needed. Conclusion: This study identified a need and priority for interdisciplinary research focusing on the long-term socio-cultural, economic and health impact of the EVD epidemic. Experiences of survivors and other non-infected members of the community still need to be explored but in this broader context
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