6,216 research outputs found

    Thomas-Fermi-Poisson theory of screening for latterally confined and unconfined two-dimensional electron systems in strong magnetic fields

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    We examine within the self-consistent Thomas-Fermi-Poisson approach the low-temperature screening properties of a two-dimensional electron gas (2DEG) subjected to strong perpendicular magnetic fields. Numerical results for the unconfined 2DEG are compared with those for a simplified Hall bar geometry realized by two different confinement models. It is shown that in the strongly non-linear screening limit of zero temperature the total variation of the screened potential is related by simple analytical expressions to the amplitude of an applied harmonic modulation potential and to the strength of the magnetic field.Comment: 12 pages, 12 figure

    Intelligent autonomous treatment of bedwetting using non-invasive wearable advanced mechatronics systems and MEMS sensors

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    Post-void alarm systems to monitor bed wetting in Nocturnal Enuresis (NE) have been deemed unsatisfactory. The aim in this study is to develop a safe, comfortable and non-invasive pre-void wearable alarm and associated technology using advanced mechatronics. Each stage of development includes patient and public involvement and engagement (PPI). The early stage of the development involved children with and without nocturnal enuresis (NE) (and parents) who were tested at a hospital under the supervision of physicians, radiologists, psychologists, and nurses. The readings were simultaneously compared to B-mode images and measurements, acquired from a conventional ultrasound device, and were found to correlate highly. The results showed that determining imminent voiding need is viable using non-invasive sensors. Following on from "proof of concept", a bespoke advanced mechatronics device has been created. The device houses custom electronics, an ultrasound system, intelligent software, a user-friendly smartphone application, bedside alarm box and a dedicated undergarment, along with a self-adhesive gel pad - designed to keep the MEMS sensors aligned with the abdomen. Testing of the device with phantoms and volunteers has been successful in determining bladder volume and associated voiding need. Five miniaturized, and therefore more ergonomic, versions of the device are being developed, with an enabled connection to the cloud platform for location independent control and monitoring. Thereafter, the enhanced device will be tested with children with NE at their homes for 14 weeks, to gain feedback relating to wearability and data collection involving the cloud platform

    Sol-Gel-Derived Hydroxyapatite-Carbon Nanotube/Titania Coatings on Titanium Substrates

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    In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO2) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO2 coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO2 coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO2 double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO2 coatings on Ti substrates might be a promising material for bone replacement

    Effect of Fasciola hepatica proteins on the functioning of rat hepatocytes

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    Fasciolosis is a hepatic parasitic infection that affects many mammal species and creates a great economic and veterinary problem. Molecular mechanisms of parasite–hepatocyte interactions have not been precisely characterized yet. Therefore, the aim of the study was to investigate alterations in the metabolic activity of rat liver cells exposed to Fasciola hepatica somatic proteins. Hepatocytes were incubated with 0–1 mg/ml of fluke's somatic proteins for various periods of time. Afterward, changes in hepatocytes metabolic activity were determined with MTT and enzyme leakage tests. Hepatocytes' capacity to synthesize albumin was also investigated. It was observed that protein concentration, as well as longevity of their action, influenced metabolic activity of rat liver cells. Diminution of hepatocytes survival rate, an increase in enzyme leakage and altered synthetic capacity after treatment with parasite's proteins were reported. It is concluded that somatic proteins of F. hepatica may play an important role in liver cell damaging

    RAFT dispersion polymerization : a method to tune the morphology of thymine-containing self-assemblies

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    YesThe synthesis and self-assembly of thymine-containing polymers were performed using RAFT dispersion polymerization. A combination of microscopy and scattering techniques was used to analyze the resultant complex morphologies. The primary observation from this study is that the obtained aggregates induced during the polymerization were well-defined despite the constituent copolymers possessing broad dispersities. Moreover, a variety of parameters, including the choice of polymerization solvent, the degree of polymerization of both blocks and the presence of an adenine-containing mediator, were observed to affect the resultant size and shape of the assembly.University of Warwick, National Science Foundation (U.S.) (NSF), Engineering and Physical Sciences Research Council (EPSRC

    Patient Engagement in Medical Device Design: Refining the Essential Attributes of a Wearable, Pre-Void, Ultrasound Alarm for Nocturnal Enuresis

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    Background To date, no pre-void wearable alarm exists to treat nocturnal enuresis (NE)—night-time bedwetting, and children with NE and their families are disappointed in relation to the post-void moisture alarms and medicine currently available. Development of a safe, comfortable and non-invasive wearable pre-void alarm and associated technology, using advanced mechatronics, is underway (the MyPAD device). Each stage of development includes patient and public involvement (PPI), particularly with respect to human factors, in collaboration with physicians, radiologists, psychologists, nurses, engineers and designers. Objectives The aim of this study was to help us understand the families’ experience of the condition of enuresis, and to provide opinion relating to existing NE alarms, designed to detect moisture, and most importantly, the initial design of the MyPAD wearable technology. Methods A PPI workshop in the form of a focus group, made up of children with enuresis and their parents, was conducted during the early stage of the MyPAD product development. The key research questions (RQs) were: (RQ1) What were the families’ experiences of using existing post-void enuresis alarms? (RQ2) What do families like about the MyPAD prototype? and (RQ3) What do families not like about the MyPAD prototype? A nurse specialised in terms of NE treatment, including post-void alarms, from the Lancashire Teaching Hospitals NHS Foundation Trust, and two MyPAD design engineers were also present, to explain the MyPAD design concept. Braun and Clarke’s six-phase approach to thematic analysis was implemented, which included familiarisation with the data, initial descriptive coding, identifying themes, reviewing themes, defining and labelling themes and producing a report. Results Four common themes were identified from the focus group discussions: the importance of sleep; children do not want to feel different; parents feel frustrated and concerned; resilience and perseverance. These themes applied across the research questions; for example, sleep disruption was highlighted as an issue with existing post-void alarms and as an important requirement for the design of MyPAD. The evaluation of the early version of the MyPAD device has prompted the consideration of changes to some existing facets of the device, including providing multiple alarm types, more options for the design of the garment that houses the device, and the need for clear, age-appropriate and informative instructions relating to how the device should be used, in order to maximise its performance/efficiency and acceptance. Conclusions The qualitative data derived from the focus group discussion was incredibly valuable as it enabled the research and design team to experience the perspectives of the families in terms of the challenges and conflicts of managing the condition and the limited utility of existing post-void alarms. This has improved our understanding of the social and environmental challenges that will need to be considered during the design process

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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