146 research outputs found

    Antenna-Based Popup Vapor Sensor Guided by Controlled Compressive Buckling

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    A novel highly stretchable gas sensor is reported that is based on popup antenna reconfiguration due to the strain induced by the swelling of a polydimethylsiloxane (PDMS) substrate when exposed to diethyl ether. When the swollen substrate is removed from the volatile solvent environment, the PDMS volume increase is reversed leading to compressive stress in an attached antenna transforming a 2D structure to a 3D structure through mechanically induced shaping. This provides a low cost and simple route to tune the antenna resonant frequency and gain in direct response to a chemical stimulus. Our proposed solvent sensor is able to measure 0 to 60% PDMS swelling corresponding to diethyl ether concentrations up to 1620 ppm via a resonant frequency shift from 4 to 2.4 GHz. A fatigue life study indicated 〖10〗^(3.5) life cycles which demonstrates the durability of these sensors to accommodate large strain and repeatability of the sensing process. Multiphysics Finite Element Method (FEM) modelling of the mechanical and RF simulations along with analytical results based on an equivalent circuit model were in good agreement with experimental data and demonstrate the potential of these structures as sensors

    Discrete cilia modelling with singularity distributions

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    We discuss in detail techniques for modelling flows due to finite and infinite arrays of beating cilia. An efficient technique, based on concepts from previous ‘singularity models’ is described, that is accurate in both near and far-fields. Cilia are modelled as curved slender ellipsoidal bodies by distributing Stokeslet and potential source dipole singularities along their centrelines, leading to an integral equation that can be solved using a simple and efficient discretisation. The computed velocity on the cilium surface is found to compare favourably with the boundary condition. We then present results for two topics of current interest in biology. 1) We present the first theoretical results showing the mechanism by which rotating embryonic nodal cilia produce a leftward flow by a ‘posterior tilt,’ and track particle motion in an array of three simulated nodal cilia. We find that, contrary to recent suggestions, there is no continuous layer of negative fluid transport close to the ciliated boundary. The mean leftward particle transport is found to be just over 1 ÎŒm/s, within experimentally measured ranges. We also discuss the accuracy of models that represent the action of cilia by steady rotlet arrays, in particular, confirming the importance of image systems in the boundary in establishing the far-field fluid transport. Future modelling may lead to understanding of the mechanisms by which morphogen gradients or mechanosensing cilia convert a directional flow to asymmetric gene expression. 2) We develop a more complex and detailed model of flow patterns in the periciliary layer of the airway surface liquid. Our results confirm that shear flow of the mucous layer drives a significant volume of periciliary liquid in the direction of mucus transport even during the recovery stroke of the cilia. Finally, we discuss the advantages and disadvantages of the singularity technique and outline future theoretical and experimental developments required to apply this technique to various other biological problems, particularly in the reproductive system

    Optimizing case reports and case series: guidance on how to improve quality

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    Case reports and case series remain an important part of journals and are often first to document medical breakthroughs. This article reviews their characteristics, aims and limitations. It provides information on how to increase the validity of the bedside decision‐making process that these studies report, using tools such as validated outcomes and split body or n‐of‐1 trials. A section describing tools to improve writing of case reports and case series provides suggestions for detailed reporting and good evaluation of novelty, validity and relevance. It includes general and British Journal of Dermatology specific guidance

    Adjustable Passive RFID Skin Mounted Sticker

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    Passive Radio Frequency Identification (RFID) can be limited by such aspects as size that make overcoming the capacitive loading introduced by human tissue difficult when intending to produce an efficient antenna with a high read range. It is still possible to design a small and thin RFID tag with a read range above half a meter. Here we present such a design with a diameter of less than 3 cm, By utilizing a breathable polyurethane polymer with two thicknesses, it is possible to use a single tag design for human tissue (dielectric constants ranging from a 22 to 40) with only a slight loss in antenna read range. It is more cost effective to just adjust the polyurethane thickness for a single design than to tune the antenna design itself. Volunteers one and two had read ranges above one meter while volunteer three (with permittivity of 40) caused the largest shift in antenna resonance from 865 MHz (EU band) and required an increase in polyurethane thickness from 1.1 mm to 1.5 mm. However, both designs still produced read ranges above 0.5 meters which could be further tuned with future adjustments to increase read range. This led to a passive RFID design that can be worn by most people with a simple thickness adjustment if needed

    Convection in colloidal suspensions with particle-concentration-dependent viscosity

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    The onset of thermal convection in a horizontal layer of a colloidal suspension is investigated in terms of a continuum model for binary-fluid mixtures where the viscosity depends on the local concentration of colloidal particles. With an increasing difference between the viscosity at the warmer and the colder boundary the threshold of convection is reduced in the range of positive values of the separation ratio psi with the onset of stationary convection as well as in the range of negative values of psi with an oscillatory Hopf bifurcation. Additionally the convection rolls are shifted downwards with respect to the center of the horizontal layer for stationary convection (psi>0) and upwards for the Hopf bifurcation (psi<0).Comment: 8 pages, 6 figures, submitted to European Physical Journal

    Home interventions and light therapy for treatment of vitiligo (HI-Light Vitiligo Trial): study protocol for a randomized controlled trial

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    Vitiligo is a condition resulting in white patches on the skin. People with vitiligo can suffer from low self-esteem, psychological disturbance and diminished quality of life. Vitiligo is often poorly managed, partly due to lack of high quality evidence to inform clinical care. We describe here a large, independent, randomised controlled trial (RCT) assessing the comparative effectiveness of potent topical corticosteroid, home-based hand-held narrowband ultraviolet B-light (NB-UVB) or combination of the two, for the management of vitiligo. Methods and Analysis The HI-Light Vitiligo Trial is a multi-centre, three-arm, parallel group, pragmatic, placebo-controlled RCT. 516 adults and children with actively spreading, but limited, vitiligo are randomised (1:1:1) to one of three groups: mometasone furoate 0.1% ointment plus dummy NB-UVB light, vehicle ointment plus NB-UVB light, or mometasone furoate 0.1% ointment plus NB-UVB light. Treatment of up to three patches of vitiligo is continued for up to 9 months with clinic visits at baseline, 3, 6 and 9 months and four post treatment questionnaires. The HI-Light Vitiligo Trial assesses outcomes included in the vitiligo core outcome set and places emphasis on participants’ views of treatment success. The primary outcome is proportion of participants achieving treatment success (patient-rated Vitiligo Noticeability Scale) for a target patch of vitiligo at 9 months with further independent blinded assessment using digital images of the target lesion before and after treatment. Secondary outcomes include time to onset of treatment response, treatment success by body region, percentage repigmentation, quality of life, time-burden of treatment, maintenance of response, safety, and within-trial cost effectiveness. Ethics and Dissemination Approvals were granted by East Midlands–Derby Research Ethics Committee (14/EM/1173) and the MHRA (EudraCT 2014-003473-42). The trial was registered 8th January 2015 ISRCTN (17160087). Results will be published in full as open access in the NIHR Journal library and elsewhere

    Supercoherent States, Super K\"ahler Geometry and Geometric Quantization

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    Generalized coherent states provide a means of connecting square integrable representations of a semi-simple Lie group with the symplectic geometry of some of its homogeneous spaces. In the first part of the present work this point of view is extended to the supersymmetric context, through the study of the OSp(2/2) coherent states. These are explicitly constructed starting from the known abstract typical and atypical representations of osp(2/2). Their underlying geometries turn out to be those of supersymplectic OSp(2/2) homogeneous spaces. Moment maps identifying the latter with coadjoint orbits of OSp(2/2) are exhibited via Berezin's symbols. When considered within Rothstein's general paradigm, these results lead to a natural general definition of a super K\"ahler supermanifold, the supergeometry of which is determined in terms of the usual geometry of holomorphic Hermitian vector bundles over K\"ahler manifolds. In particular, the supergeometry of the above orbits is interpreted in terms of the geometry of Einstein-Hermitian vector bundles. In the second part, an extension of the full geometric quantization procedure is applied to the same coadjoint orbits. Thanks to the super K\"ahler character of the latter, this procedure leads to explicit super unitary irreducible representations of OSp(2/2) in super Hilbert spaces of L2L^2 superholomorphic sections of prequantum bundles of the Kostant type. This work lays the foundations of a program aimed at classifying Lie supergroups' coadjoint orbits and their associated irreducible representations, ultimately leading to harmonic superanalysis. For this purpose a set of consistent conventions is exhibited.Comment: 53 pages, AMS-LaTeX (or LaTeX+AMSfonts

    Recent Developments in Understanding Two-dimensional Turbulence and the Nastrom-Gage Spectrum

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    Two-dimensional turbulence appears to be a more formidable problem than three-dimensional turbulence despite the numerical advantage of working with one less dimension. In the present paper we review recent numerical investigations of the phenomenology of two-dimensional turbulence as well as recent theoretical breakthroughs by various leading researchers. We also review efforts to reconcile the observed energy spectrum of the atmosphere (the spectrum) with the predictions of two-dimensional turbulence and quasi-geostrophic turbulence.Comment: Invited review; accepted by J. Low Temp. Phys.; Proceedings for Warwick Turbulence Symposium Workshop on Universal features in turbulence: from quantum to cosmological scales, 200

    A 14-year experience with kidney transplantation.

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    Between November, 1962 and August, 1975, 668 kidney transplants were done in 556 consecutive patients at Denver, Colorado. The Denver experience has been divided into 7 periods of time, according to the conditions of care during each period. The results in related transplantation have changed little during the decade beginning in 1966. The results in unrelated transplantation have not materially changed since 1968. The long-term patient survival after related transplantation has been better than after cadaver transplantation. The results of transplantation in 57 children ages 3 to 18 years have been slightly better than the results of adult transplantation. The outcome of kidney transplantation and the feasibility of improving this therapy with present techniques are limited by our inability to accurately match each patient with the immunologically best donor and by our inability to precisely control the immune system of the recipient. Rejection is still the main reason for graft loss, and sepsis remains the main cause of patient mortality. More specific and less toxic means of achieving graft acceptance are needed before a higher level of patient service can be realized. However, even with the tools now available, thousands of recipients throughout the world have been returned to useful lives

    Reading religion in Norwegian textbooks: are individual religions ideas or people?

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    Different religions are treated in different ways in Norwegian sixth form textbooks. We carried out an exhaustive content analysis of the chapters devoted to individual religions in textbooks for the Religion and Ethics course currently available in Norway, using rigorous indicators to code each word, image and question according to whether they were treated the religion as a set of ideas or a group of people. After adjusting for trends in the different kinds of data (word, image, question), we found that Buddhism and Christianity receive significantly more attention for their ideas than Hinduism, Islam and Judaism, which are treated more as people. This difference cannot be explained by the national syllabus or the particularities of the individual religions. The asymmetry also has implications for the pupils’ academic, moral and pedagogical agency for which teachers play a critical role in compensating.acceptedVersio
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