5,982 research outputs found

    Measurements of the free stream fluctuations above a turbulent boundary layer

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    This paper investigates the velocity fluctuations in the free stream above an incompressible turbulent boundary layer developing at constant pressure. It is assumed that the fluctuations receive contributions from three statistically independent sources: (1) one-dimensional unsteadiness, (2) free stream turbulence, and (3) the potential motion induced by the turbulent boundary layer. Measurements were made in a wind tunnel with a root-mean-square level of the axial velocity fluctuations of about 0.2 percent. All three velocity components were measured using an X-wire probe. The unsteadiness was determined from the spanwise covariance of the axial velocity, measured using two single wire probes. The results show that it is possible to separate the contributions to the r.m.s. level of the velocity fluctuations, without resorting to the dubious technique of high-pass filtering. The separation could be extended to the spectral densities of the contributions, if measurements of sufficient accuracy were available. The Appendix provides a general guide for the measurement of small free stream fluctuation levels

    Neurofibromin knockdown in glioma cell lines is associated with changes in cytokine and chemokine secretion in vitro.

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    The neurofibromin-1 tumor suppressor gene (NF1) is altered in approximately 20% of sporadic glioblastoma (GBM) cases. NF1 deficient GBM frequently shows a mesenchymal gene expression signature, suggesting a relationship between NF1 status and the tumor microenvironment. To identify changes in the production of secreted cytokines/chemokines in NF1 deficient glioma, we applied cytokine arrays to conditioned media from a panel of three GBM cell lines after siRNA-mediated NF1 knockdown. We identified increased secretion of platelet-derived growth factor AA (PDGF-AA), chitinase-3-like protein 1 (CHI3L1), interleukin-8 (IL-8), and endoglin (ENG) in different subsets of these cell lines. Secretion was associated with induction of the corresponding messenger RNA, suggesting a mechanism involving transcriptional upregulation. By contrast, in non-transformed immortalized normal human astrocytes, PDGF-AA secretion was increased upon NF1 knockdown, while secreted CHI3L1, ENG, and IL-8 were reduced or unchanged. Analysis of The Cancer Genome Atlas confirmed a relationship between glioma NF1 status and ENG and CHI3L1 in tumor samples. Overall, this study identifies candidate changes in secreted proteins from NF1 deficient glioma cells that could influence the tumor microenvironment, and suggests a direct link between NF1 loss and increased tumor cell production of CHI3L1 and endoglin, two factors implicated in mesenchymal identity in glioblastoma

    IJBNPA in 2016:Strategy for advancing the science of behavior change in nutrition and physical activity, and associated editorial priorities

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    The goal of the International Journal of Behavioral Nutrition and Physical Activity (IJBNPA) is to be the leading diet and physical activity journal. To achieve this aim we embrace and publish a number of different research designs from small, but in depth, qualitative studies to large scale cohort studies. IJBNPA prioritises research based on randomised controlled trials (RCTs), systematic reviews (with or without meta-analyses, as appropriate), and well conducted observational studies that expand knowledge and understanding of the area. IJBNPA will also consider and publish other study designs that are of sufficient quality such as strong or ground-breaking methodological papers, rigorous qualitative studies, debate papers and commentaries. However, due to the demands on the journal, we publish pilot studies only in exceptional circumstances and we do not publish protocol papers or letters to the editors. The goal of this editorial is to highlight to our readers and authors the process by which we identify which papers to review and publish along with our editorial priorities

    Summary care record early adopter programme: an independent evaluation by University College London.

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    Benefits The main potential benefit of the SCR is considered to be in emergency and unscheduled care settings, especially for people who are unconscious, confused, unsure of their medical details, or unable to communicate effectively in English. Other benefits may include improved efficiency of care and avoidance of hospital admission, but it is too early for potential benefits to be verified or quantified. Progress As of end April 2008, the SCR of 153,188 patients in the first two Early Adopter sites (Bolton and Bury) had been created. A total of 614,052 patients in four Early Adopter sites had been sent a letter informing them of the programme and their choices for opting out of having a SCR. Staff attitudes and usage The evaluation found that many NHS staff in Early Adopter sites (which had been selected partly for their keenness to innovate in ICT) were enthusiastic about the SCR and keen to see it up and running, but a significant minority of GPs had chosen not to participate in the programme and others had deferred participation until data quality improvement work was completed. Whilst 80 per cent of patients interviewed were either positive about the idea of having a SCR or ?did not mind?, others were strongly opposed ?on principle?. Staff who had attempted to use the SCR when caring for patients felt that the current version was technically immature (describing it as ?clunky? and ?complicated?), and were looking forward to a more definitive version of the technology. A comparable technology (the Emergency Care Summary) introduced in Scotland two years ago is now working well, and over a million records have been accessed in emergency and out-of-hours care. Patient attitudes and awareness Having a SCR is optional (people may opt out if they wish, though fewer than one per cent of people in Early Adopter sites have done so) and technical security is said to be high via a system of password protection and strict access controls. Nevertheless, the evaluation showed that recent stories about data loss by government and NHS organisations had raised concerns amongst both staff and patients that human fallibility could potentially jeopardise the operational security of the system. Despite an extensive information programme to inform the public in Early Adopter sites about the SCR, many patients interviewed by the UCL team were not aware of the programme at all. This raises important questions about the ethics of an ?implied consent? model for creating the SCR. The evaluation recommended that the developers of the SCR should consider a model in which the patient is asked for ?consent to view? whenever a member of staff wishes to access their record. Not a single patient interviewed in the evaluation was confident that the SCR would be 100 per cent secure, but they were philosophical about the risks of security breaches. Typically, people said that the potential benefit of a doctor having access to key medical details in an emergency outweighed the small but real risk of data loss due to human or technical error. Even patients whose medical record contained potentially sensitive data such as mental health problems, HIV or drug use were often (though not always) keen to have a SCR and generally trusted NHS staff to treat sensitive data appropriately. However, they and many other NHS patients wanted to be able to control which staff members were allowed to access their record at the point of care. Some doctors, nurses and receptionists, it seems, are trusted to view a person?s SCR, whereas others are not, and this is a decision which patients would like to make in real time

    Structure-property-function relationships in triple helical collagen hydrogels

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    In order to establish defined biomimetic systems, type I collagen was functionalised with 1,3-Phenylenediacetic acid (Ph) as aromatic, bifunctional segment. Following investigation on molecular organization and macroscopic properties, material functionalities, i.e. degradability and bioactivity, were addressed, aiming at elucidating the potential of this collagen system as mineralization template. Functionalised collagen hydrogels demonstrated a preserved triple helix conformation. Decreased swelling ratio and increased thermo-mechanical properties were observed in comparison to state-of-the-art carbodiimide (EDC)-crosslinked collagen controls. Ph-crosslinked samples displayed no optical damage and only a slight mass decrease (∼ 4 wt.-%) following 1-week incubation in simulated body fluid (SBF), while nearly 50 wt.-% degradation was observed in EDC-crosslinked collagen. SEM/EDS revealed amorphous mineral deposition, whereby increased calcium phosphate ratio was suggested in hydrogels with increased Ph content. This investigation provides valuable insights for the synthesis of triple helical collagen materials with enhanced macroscopic properties and controlled degradation. In light of these features, this system will be applied for the design of tissue-like scaffolds for mineralized tissue formation

    Do Employees From Less-Healthy Communities Use More Care and Cost More? Seeking to Establish a Business Case for Investment in Community Health.

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    INTRODUCTION: Few studies have examined the impact of community health on employers. We explored whether employed adults and their adult dependents living in less-healthy communities in the greater Philadelphia region used more care and incurred higher costs to employers than employees from healthier communities. METHODS: We used a multi-employer database to identify adult employees and dependents with continuous employment and mapped them to 31 zip code regions. We calculated community health scores at the regional level, by using metrics similar to the Robert Wood Johnson Foundation (RWJF) County Health Rankings but with local data. We used descriptive analyses and multilevel linear modeling to explore relationships between community health and 3 outcome variables: emergency department (ED) use, hospital use, and paid claims. Business leaders reviewed findings and offered insights on preparedness to invest in community health improvement. RESULTS: Poorer community health was associated with high use of ED services, after controlling for age and sex. After including a summary measure of racial composition at the zip code region level, the relationship between community health and ED use became nonsignificant. No significant relationships between community health and hospitalizations or paid claims were identified. Business leaders expressed interest in further understanding health needs of communities where their employees live. CONCLUSION: The health of communities in which adult employees and dependents live was associated with ED use, but similar relationships were not seen for hospitalizations or paid claims. This finding suggests a need for more primary care access. Despite limited quantitative evidence, business leaders expressed interest in guidance on investing in community health improvement

    In-situ crosslinked wet spun collagen triple helices with nanoscale-regulated ciprofloxacin release capability

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    The design of antibacterial-releasing coatings or wrapping materials with controlled drug release capability is a promising strategy to minimise risks of infection and medical device failure in vivo. Collagen fibres have been employed as medical device building block, although they still fail to display controlled release capability, competitive wet-state mechanical properties, and retained triple helix organisation. We investigated this challenge by pursuing a multiscale design approach integrating drug encapsulation, in-situ covalent crosslinking and fibre spinning. By selecting ciprofloxacin (Cip) as a typical antibacterial drug, wet spinning was selected as a triple helix-friendly route towards Cip-encapsulated collagen fibres; whilst in–situ crosslinking of fibre-forming triple helices with 1,3–phenylenediacetic acid (Ph) was hypothesised to yield Ph-Cip π-π stacking aromatic interactions and enable controlled drug release. Higher tensile modulus and strength were measured in Ph–crosslinked fibres compared to state-of-the-art carbodiimide–crosslinked controls. Cip-encapsulated Ph-crosslinked fibres revealed decreased elongation at break and significantly-enhanced drug retention in vitro with respect to Cip-free variants and carbodiimide-crosslinked controls, respectively. This multiscale manufacturing strategy provides new insight aiming at wet spun collagen triple helices with nanoscale-regulated tensile properties and drug release capability
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