232 research outputs found
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The monitoring of an existing cast iron tunnel with distributed fibre optic sensing (DFOS)
Instrumentation is vital to tunnelling projects for validation of design assumptions, monitoring of trigger levels during construction and also serving as a feedback loop to understand the deformation mechanisms of the particular problem which could be used to improve future designs. It can also be used for long term monitoring of the tunnel for maintenance purposes. Distributed fibre optic sensing (DFOS) systems based on brillouin optical time domain reflectometry are able to provide continuous and distributed strain measurements to be taken along the entire length of, for example, an existing cast iron tunnel where the fibre optic cable length is fully attached. This enables engineers to understand the stresses and strains that develop within the lining caused by external influences; which in this case, the construction of a new tunnel directly underneath it, rather than relying on discrete point measurements of displacement from conventional methods of monitoring. Nonetheless, proper installation of DFOS is of paramount importance to obtain high quality data. This paper aims to provide some practical guidance on the planning and installation of DFOS and presents a brief case study on the monitoring of London’s Royal Mail tunnel during the construction of the large Crossrail platform tunnel, located directly below it at Liverpool Street Station. It demonstrates the potential benefits of using such systems in complex tunnelling scenarios.The authors would like to gratefully note the contributions in the form of logistical and technical support from Crossrail (particularly Mike Black, Stephen Roberts, Alison Norrish and Chris Dulake), Royal Mail (particularly Mitch Harris), ARUP (particularly Mike Devriendt), CH2 M Hill (particularly Peter Wright). This project would not have been possible without the financial support from Laing O’Rourke for the first author’s PhD studentship as well as the continuous support from the UK Engineering and Physical Sciences Research Council (EPSRC) and Innovate UK through their funding of the Centre for Smart Infrastructure and Construction (CSIC) at Cambridge.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s13349-015-0109-
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Monitoring the effects of tunnelling under an existing tunnel-fibre optics
Underground tunnel networks are at the heart of United Kingdom's infrastructure, carrying more than 1,100 million passengers each year along its 249 miles long network via 11 underground lines, serving 270 stations.With a complex existing underground rail network already in place; it is inevitable that new tunnels will be constructed within close proximity to existing tunnels. At London Liverpool Street Station, the new eastbound Crossrail platformtunnel was constructed underneath the existing Royal MailTunnel at a parallel alignment over a length of over 100m with a clear distance of less than 2m separating the two. Fibre optic strain sensing system based on Brillouin Optical Time Domain Reflectometry (BOTDR) was installed to measure continuous strain profiles of the cast iron linings of Royal Mail Tunnel. This has provided valuable insights to the deformation mechanisms both during the pilot and final tunnel enlargement. © 2014 Korean Geotechnical Society
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Tunnelling close beneath an existing tunnel in clay – perpendicular undercrossing
A series of centrifuge model tests in clay was carried out to investigate the response of an existing tunnel at different clear distances to new tunnelling. A three-dimensional (3D) staged tunnelling model was adopted to simulate a wide range of tail void volume losses for the new tunnel construction while monitoring detailed 3D soil surface settlements and tunnelling-induced strains in the existing tunnel lining. This paper also presents a detailed case study of a similar scenario in the London Underground redevelopment of Bond Street station; various state-of-the-art instrumentation methods, including fibre optic Brillouin optical time domain reflectometry, instrumented tunnel bolts and photogrammetry, were deployed to monitor the response of the existing Royal Mail tunnel due to the new tunnelling works close beneath. The combination of field and centrifuge modelling data provides important new insights into the deformation mechanisms encountered in such complex tunnelling scenarios.This research would not have been possible without financial support from Laing O'Rourke plc for the first author's PhD studentship. The authors would also like to acknowledge the logistical and technical support provided by London Underground, Royal Mail Group Ltd, CH2M Hill and the Schofield Centre technicians and the continuous support from the UK Engineering and Physical Sciences Research Council (EPSRC) and Innovate UK through their funding of the Cambridge Centre for Smart Infrastructure and Construction (CSIC)
Chronic Delivery of Antibody Fragments Using Immunoisolated Cell Implants as a Passive Vaccination Tool
BACKGROUND: Monoclonal antibodies and antibody fragments are powerful biotherapeutics for various debilitating diseases. However, high production costs, functional limitations such as inadequate pharmacokinetics and tissue accessibility are the current principal disadvantages for broadening their use in clinic.
METHODOLOGY AND PRINCIPAL FINDINGS: We report a novel method for the long-term delivery of antibody fragments. We designed an allogenous immunoisolated implant consisting of polymer encapsulated myoblasts engineered to chronically release scFv antibodies targeted against the N-terminus of the Aβ peptide. Following a 6-month intracerebral therapy we observed a significant reduction of the production and aggregation of the Aβ peptide in the APP23 transgenic mouse model of Alzheimer's disease. In addition, functional assessment showed prevention of behavioral deficits related to anxiety and memory traits.
CONCLUSIONS AND SIGNIFICANCE: The chronic local release of antibodies using immunoisolated polymer cell implants represents an alternative passive vaccination strategy in Alzheimer's disease. This novel technique could potentially benefit other diseases presently treated by local and systemic antibody administration
Efficacy of Memantine for Agitation in Alzheimer’s Dementia: A Randomised Double-Blind Placebo Controlled Trial
Agitation in Alzheimer's disease (AD) is common and associated with poor patient life-quality and carer distress. The best evidence-based pharmacological treatments are antipsychotics which have limited benefits with increased morbidity and mortality. There are no memantine trials in clinically significant agitation but post-hoc analyses in other populations found reduced agitation. We tested the primary hypothesis, memantine is superior to placebo for clinically significant agitation, in patients with moderate-to-severe AD
Psychometric properties of a generic, patient-centred palliative care outcome measure of symptom burden for people with progressive long term neurological conditions
Background
There is no standard palliative care outcome measure for people with progressive long term neurological conditions (LTNC). This study aims to determine the psychometric properties of a new 8-item palliative care outcome scale of symptom burden (IPOS Neuro-S8) in this population.
Data and Methods
Data were merged from a Phase II palliative care intervention study in multiple sclerosis (MS) and a longitudinal observational study in idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). The IPOS Neuro-S8 was assessed for its data quality, score distribution, ceiling and floor effects, reliability, factor structure, convergent and discriminant validity, concurrent validity with generic (Palliative care Outcome Scale) and condition specific measures (Multiple Sclerosis Impact Scale; Non-motor Symptoms Questionnaire; Parkinson's Disease Questionnaire), responsiveness and minimally clinically important difference.
Results
Of the 134 participants, MS patients had a mean Extended Disability Status Scale score 7.8 (SD = 1.0), patients with an IPD, MSA or PSP were in Hoehn & Yahr stage 3±5. The IPOS Neuro-S8 had high data quality (2% missing), mean score 8 (SD = 5; range 0±32), no ceiling effects, borderline floor effects, good internal consistency (Cronbach's α = 0.7) and moderate test-retest reliability (intraclass coefficient = 0.6). The results supported a moderately correlated two-factor structure (Pearson's r = 0.5). It was moderately correlated with generic and condition specific measures (Pearson's r: 0.5±0.6). There was some evidence for discriminant validity in IPD, MSA and PSP (p = 0.020), and for good responsiveness and longitudinal construct validity.
Conclusions
IPOS Neuro-S8 shows acceptable to promising psychometric properties in common forms of progressive LTNCs. Future work needs to confirm these findings with larger samples and its usefulness in wider disease groups
The Winchcombe meteorite, a unique and pristine witness from the outer solar system.
Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water
Mixed Cerebrovascular Disease and the Future of Stroke Prevention
Stroke prevention efforts typically focus on either ischemic or hemorrhagic stroke. This approach is overly simplistic due to the frequent coexistence of ischemic and hemorrhagic cerebrovascular disease. This coexistence, termed “mixed cerebrovascular disease”, offers a conceptual framework that appears useful for stroke prevention strategies. Mixed cerebrovascular disease incorporates clinical and subclinical syndromes, including ischemic stroke, subclinical infarct, white matter disease of aging (leukoaraiosis), intracerebral hemorrhage, and cerebral microbleeds. Reliance on mixed cerebrovascular disease as a diagnostic entity may assist in stratifying risk of hemorrhagic stroke associated with platelet therapy and anticoagulants. Animal models of hemorrhagic cerebrovascular disease, particularly models of cerebral amyloid angiopathy and hypertension, offer novel means for identifying underlying mechanisms and developing focused therapy. Phosphodiesterase (PDE) inhibitors represent a class of agents that, by targeting both platelets and vessel wall, provide the kind of dual actions necessary for stroke prevention, given the spectrum of disorders that characterizes mixed cerebrovascular disease
Positioning pharmacists’ roles in primary health care: a discourse analysis of the compensation plan in Alberta, Canada
Abstract Background A comprehensive Compensation Plan for pharmacy services delivered by community pharmacists was implemented in Alberta, Canada in July 2012. Services covered by the Compensation Plan include care planning services, prescribing services such as adapting prescriptions, and administering a drug or publicly-funded vaccine by injection. Understanding how the Compensation Plan was framed and communicated provides insight into the roles of pharmacists and the potential influence of language on the implementation of services covered by the Compensation Plan by Albertan pharmacists. The objective of this study is to examine the positioning of pharmacists’ roles in documents used to communicate the Compensation Plan to Albertan pharmacists and other audiences. Methods Publicly available documents related to the Compensation Plan, such as news releases or reports, published between January 2012 and December 2015 were obtained from websites such as the Government of Alberta, Alberta Blue Cross, the Alberta College of Pharmacists, the Alberta Pharmacists’ Association, and the Blueprint for Pharmacy. Searches of the Canadian Newsstand database and Google identified additional documents. Discourse analysis was performed using social positioning theory to explore how pharmacists’ roles were constructed in communications about the Compensation Plan. Results In total, 65 publicly available documents were included in the analysis. The Compensation Plan was put forward as a framework for payment for professional services and formal legitimization of pharmacists’ changing professional roles. The discourse associated with the Compensation Plan positioned pharmacists’ roles as: (1) expanding to include services such as medication management for chronic diseases, (2) contributing to primary health care by providing access to services such as prescription renewals and immunizations, and (3) collaborating with other health care team members. Pharmacists’ changing roles were positioned in alignment with the aims of primary health care. Conclusions Social positioning theory provides a useful lens to examine the dynamic and evolving roles of pharmacists. This study provides insight into how communications regarding the Compensation Plan in Alberta, Canada positioned pharmacists’ changing roles in the broader context of changes to primary health care delivery. Our findings may be useful for other jurisdictions considering implementation of remunerated clinical services provided by pharmacists
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