2,394 research outputs found

    Bifurcated Dacron patch for simultaneous superficial femoroplasty and profundoplasty: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Common femoral endarterectomy and/or profundoplasty are procedures commonly performed on patients with functional or critical limb ischaemia.</p> <p>Case presentation</p> <p>A 61-year-old Caucasian British man was referred to our unit with recent onset of severe left calf and thigh claudication and rest pain in his left foot. Magnetic resonance angiography revealed occlusive disease of the left common femoral artery, proximal superficial and profunda femoral arteries.</p> <p>These findings were confirmed intraoperatively and an endarterectomy was subsequently performed from the left common femoral onto the proximal superficial femoral artery and then onto the proximal profunda femoris artery. The arteriotomy was closed with a Dacron patch and its distal end was bisected into two to patch the profunda femoris and superficial femoral arteries. The patient made an uneventful recovery with a full clinical improvement of his left leg.</p> <p>Conclusion</p> <p>A Dacron patch that was bisected distally to make a bifurcated patch for simultaneous patching of the profunda femoris artery and the superficial femoral artery was used to treat our patient's occlusions. This technique has not been previously described in the published literature and we have found it easy to do with little time added to conventional operation.</p

    Extracorporeal membrane oxygenation simulation-based training: methods, drawbacks and a novel solution

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    Introduction: Patients under the error-prone and complication-burdened extracorporeal membrane oxygenation (ECMO) are looked after by a highly trained, multidisciplinary team. Simulation-based training (SBT) affords ECMO centers the opportunity to equip practitioners with the technical dexterity required to manage emergencies. The aim of this article is to review ECMO SBT activities and technology followed by a novel solution to current challenges. ECMO simulation: The commonly-used simulation approach is easy-to-build as it requires a functioning ECMO machine and an altered circuit. Complications are simulated through manual circuit manipulations. However, scenario diversity is limited and often lacks physiological and/or mechanical authenticity. It is also expensive to continuously operate due to the consumption of highly specialized equipment. Technological aid: Commercial extensions can be added to enable remote control and to automate circuit manipulation, but do not improve on the realism or cost-effectiveness. A modular ECMO simulator: To address those drawbacks, we are developing a standalone modular ECMO simulator that employs affordable technology for high-fidelity simulation.Peer reviewe

    Advances in pultiple-pulse radio-frequency-gradient imaging of solids

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    Magnetic resonance imaging (MRI) has become the premier tool for the non-destructive evaluation of soft tissue in living systems [1]. Established liquid-state MRI strategies are generally found to be inappropriate for the imaging of rigid solids, because the linewidth for nuclear magnetic resonance in solids is orders-of-magnitude larger than in liquids. Methods currently under development for the NMR imaging of solids either involve the use of very large (fringe-field) magnetic field gradients to encode spatial information over very short periods of time [2], or employ multiple-pulse line-narrowing techniques that prolong a solid’s apparent transverse relaxation time [3–7]. In the latter methods, the magnetic field gradients may be much weaker, but must generally be pulsed synchronously with the line-narrowing sequence. The benefits of implementing this are improved sensitivity and spectroscopic resolution

    Corrigendum: Solar cycles or random processes? Evaluating solar variability in Holocene climate records

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    This is the final version of the article. Available from Springer Nature via the DOI in this record.The article to which this is the corrigendum is in ORE at http://hdl.handle.net/10871/21766A coding error in the Monte Carlo procedure for the determination of critical values in running correlation analysis (presented in Supplementary Data S8) has been brought to the attention of the authors.[...

    Glutamate spill-over in substantia nigra pars compacta

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    N-Methyl-D-aspartate glutamate receptors (NMDARs) contribute to neural development, plasticity and survival, but they are also linked with neurodegeneration. NMDARs at synapses are activated by coincident glutamate release and depolarization. NMDARs distal to synapses can sometimes be recruited by 'spill-over' of glutamate during high-frequency synaptic stimulation or when glutamate uptake is compromised, and this influences the shape of NMDAR-mediated postsynaptic responses. In substantia nigra dopamine neurons, activation of NMDARs beyond the synapse during different frequencies of presynaptic stimulation has not been explored, even though excitatory afferents from the subthalamic nucleus show a range of firing frequencies, and these frequencies change in human and experimental Parkinson's disease. This study reports that high-frequency stimulation (80 Hz/200 ms) evoked NMDAR-excitatory postsynaptic currents (EPSCs) that were larger and longer lasting than those evoked by single stimuli at low frequency (0.1 Hz). MK-801, which irreversibly blocked NMDAR-EPSCs activated during 0.1-Hz stimulation, left a proportion of NMDAR-EPSCs that could be activated by 80-Hz stimulation and that may represent activity of NMDARs distal to synapses. TBOA, which blocks glutamate transporters, significantly increased NMDAR-EPSCs in response to 80-Hz stimulation, particularly when metabotropic glutamate receptors (mGluRs) were also blocked, indicating that recruitment of NMDARs distal to synapses is regulated by glutamate transporters and mGluRs. These regulatory mechanisms may be essential in the substantia nigra for restricting glutamate diffusion from synaptic sites and keeping NMDAR-EPSCs in dopamine neurons relatively small and fast. Failure of glutamate transporters may contribute to the declining health of dopamine neurons during pathological conditions.Funding from The Wellcome Trust (092611/B/10/Z), The Isaac Newton Trust, and a BBSRC-DTP Studentship to PGM.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/ejn.1307

    Dynamics of trimming the content of face representations for categorization in the brain

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    To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1) Over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2) Concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g. the eyes) to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g. the wide opened eyes in 'fear'; the detailed mouth in 'happy'). Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300

    Modulation of gene-specific epigenetic states and transcription by non-coding RNAs

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    Emerging evidence points to a role for long non-coding RNAs in the modulation of epigenetic states and transcription in human cells. New insights, using various forms of small non-coding RNAs, suggest that a mechanism of action is operative in human cells, which utilizes non-coding RNAs to direct epigenetic marks to homology containing loci resulting ultimately in the epigenetic-based modulation of gene transcription. Importantly, insights into this mechanism of action have allowed for certain target sequences, which are either actively involved in RNA mediated epigenetic regulation or targets for non-coding RNA based epigenetic regulation, to be selected. As such, it is now feasible to utilize small antisense RNAs to either epigenetically silence a gene expression or remove epigenetic silencing of endogenous non-coding RNAs and essentially turn on a gene expression. Knowledge of this emerging RNA-based epigenetic regulatory network and our ability to cognitively control gene expression has deep implications in the development of an entirely new area of pharmacopeia

    Community energy storage: A case study in the UK using a linear programming method

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    In this paper, we investigate how energy storage can be used to increase the value of community energy schemes through cost reductions, infrastructure support, increased scheme membership, and reduced carbon emissions. A linear programming optimisation framework is developed to schedule the operation of behind-the-meter energy storage such that costs are minimised, while keeping peak demands within allowable limits. This is also extended to model generation-integrated energy storage systems, where the storage is located in the flow of energy from primary source (e.g. wind) to a usable form (e.g. electricity). To demonstrate the potential of energy storage within a real community energy scheme, we present a case study of a community hydro scheme in North Wales, considering both battery storage and a reservoir-based storage system. It is found that either system can be used to substantially increase the membership of the scheme while avoiding impacts on the electricity network, but that storage remains prohibitively expensive when used for self-consumption of renewables and arbitrage. We also investigate the impacts of energy storage on the community's carbon emissions, showing that storage operation appears to provide very little additional reduction in emissions when grid average emissions factors are used

    A systematic review of peer mentoring interventions for people with traumatic brain injury

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    Objective: This systematic review sought evidence concerning the effectiveness of peer mentoring for people with traumatic brain injury. Data sources: Fourteen electronic databases were searched, including PsycINFO, MEDLINE, CINAHL, EMBASE and the Cochrane Library, from inception to September 21 2016. Ten grey literature databases, PROSPERO, two trials registers, reference lists and author citations were also searched. Review methods: Studies which employed a model of one-to-one peer mentoring between traumatic brain injury survivors were included. Two reviewers independently screened all titles and abstracts before screening full texts of shortlisted studies. A third reviewer resolved disagreements. Two reviewers independently extracted data and assessed studies for quality and risk of bias. Results: The search returned 753 records, including one identified through hand searching. 495 records remained after removal of duplicates and 459 were excluded after screening. Full texts were assessed for the remaining 36 studies and six met the inclusion criteria. All were conducted in the United States between 1996 and 2012 and employed a variety of designs including two randomised controlled trials. A total of 288 people with traumatic brain injury participated in the studies. No significant improvements in social activity level or social network size were found, but significant improvements were shown in areas including behavioural control, mood, coping and quality of life. Conclusion: There is limited evidence for the effectiveness of peer mentoring after traumatic brain injury. The available evidence comes from small-scale studies, of variable quality, without detailed information on the content of sessions or the β€˜active ingredient’ of the interventions
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