12,742 research outputs found

    Botulinum toxin for cervical dystonia: addressing treatment failure and improving outcomes

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    Introduction. Cervical dystonia is a form of focal dystonia characterised by tilting and turning of the head and neck. This can cause significant disability in affected patients. Botulinum toxin injections are the mainstay of therapy. However, approximately 30% of patients discontinue treatment.Clinical reflections. Tyƛlerowicz et al. have provided a comprehensive review of the factors contributing to treatment failure. Such factors include appropriate identification of dystonia patterns, accurate injection of muscles, and addressing non-motor features of cervical dystonia.Clinical implications. A systematic approach is needed to identify and address the potentially modifiable factors that contributeto treatment failure

    Discontinuous Molecular Dynamics for Rigid Bodies: Applications

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    Event-driven molecular dynamics simulations are carried out on two rigid body systems which differ in the symmetry of their molecular mass distributions. First, simulations of methane in which the molecules interact via discontinuous potentials are compared with simulations in which the molecules interact through standard continuous Lennard-Jones potentials. It is shown that under similar conditions of temperature and pressure, the rigid discontinuous molecular dynamics method reproduces the essential dynamical and structural features found in continuous-potential simulations at both gas and liquid densities. Moreover, the discontinuous molecular dynamics approach is demonstrated to be between 2 to 100 times more efficient than the standard molecular dynamics method depending on the specific conditions of the simulation. The rigid discontinuous molecular dynamics method is also applied to a discontinuous-potential model of a liquid composed of rigid benzene molecules, and equilibrium and dynamical properties are shown to be in qualitative agreement with more detailed continuous-potential models of benzene. Qualitative differences in the dynamics of the two models are related to the relatively crude treatment of variations in the repulsive interactions as one benzene molecule rotates by another.Comment: 14 pages, double column revte

    Multi-Sensor System For Level Measurements With Optical Fibres

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    A system for measuring liquid level in multiple tanks using optical fibre technology has been developed. The oil field service industry can benefit from this intrinsically safe technology. Plastic optical fibre (POF) sensor heads are excited by a 650 nm laser. Laser diodes are housed in ST connectors to obtain compact and rough prototypes and these connectors are also used in the fibre pigtails. Optical multiplexing is used to increase the measuring safety area. POF splitters and connectors are used to combine all the receiving sensor head fibres in a single one. Frequency division multiplexing is used to address each sensor head. The global system is controlled through a user friendly software application running in a PC connected to the system via an RS-232 port. A scalable prototype with a range greater than 2 meter, good linearity, better than 1.5% FS (full scale), high accuracy and resolution is developed using a unique lens to collimate and focus the light. Measurements are taken to validate the designs. Up to 8 sensor heads can be connected in the present implementation. But a greater number of sensors can be allocated with minor modifications in the electronics.Universidad Carlos III de MadridPublicad

    Teaching intervention to enhance HIV infection awareness in a biomedical science degree

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Condom use remains the predominant prophylactic intervention to control rates of human immunodeficiency virus (HIV) infection. However, chemoprophylactic strategies, which involve pre-exposure prophyaxis (PrEP) and post-exposure prophyaxis (PEP), have emerged as appropriate prevention tools to minimise and prevent future infections. Different studies have indicated that PrEP can prevent new HIV infections among men who have sex with men when used daily or event-based, and it is also effective with heterosexuals and people who inject drugs. However, appropriate education is needed as recent reports have observed a decline in adherence to PrEP over time, particularly in young adults, which will impact on the effectiveness of PrEP. Thus, we created a brief educational short intervention (3 hours) to increase the awareness of HIV with second year BMedSci Medical Science (Hons) students at De Montfort University (DMU, UK) in 2016/17 (Peña-Fernåndez et al., 2017). Briefly, BMedSci students tailored a community-centred intervention programme to reduce HIV infection rates following evidence-based public health methodology. 92% indicated an acquisition of knowledge for preventing HIV transmission and tools to fight this disease. However, BMedSci students also showed a lack of knowledge of preventative measures (PrEP and PEP), routes of transmission and appropriate screening. We implemented a similar teaching strategy with BSc Biomedical Science (BMS) students enrolled in the level 4 module of Basic Microbiology in 2017/18, but limited to two hours: one-hour lecture and one hour workshop in which different HIV prevention strategies were discussed and analysed by students. BMS students were also provided with an overview about the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90:90:90 targets in the UK (2016). In a similar way as with the BMedSci cohort, BMS students showed little awareness about PEP/PrEP, specifically knowledge about what are they/how they work, access and usage. This teaching intervention was well-received by students according to the feedback provided in the final module level feedback. BMS participants (n=27 out of 187 students) indicated that they enjoyed the session and suggested a practical session and the introduction of case studies to enhance the teaching intervention. We are developing a virtual clinical case study on HIV following recent successful experiences in the development and introduction of these novel learning strategies and have performed small modifications in the delivery of this workshop for 2018/19 to increase engagement and interaction. In conclusion, we consider that similar short education interventions that specifically target HIV chemoprophylaxis would be needed in any degree to prevent the decline in adherence to PrEP over time observed in young adults and reduce PEP/PrEP stigma and other barriers which could impede their access

    A review on the turbulence modelling strategy for ship hydrodynamic simulations

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    Ship operations are accompanied by turbulent regimes that play a significant role in the hydrodynamic characteristics. With the ongoing development of computational technologies, it is now feasible to numerically simulate turbulent ship flows with a high degree of detail. Turbulent simulations, however, tend to be computationally expensive and require a trade off between computational costs and fidelity. Whilst a range of turbulence modelling strategies is available in Computational Fluid Dynamics, there is a lack of up-to-date recommendations on their suitability for different ship-flow simulation scenarios. Addressing this gap, the present work reviews the state-of-the-art of turbulence modelling for ship hydrodynamic applications. As a result, this paper introduces the most known turbulence modelling approaches used in the field, followed by a thorough discussion of their applicabilities and limitations. Furthermore, this paper provides recommendations for the selection of turbulence modelling strategies versus various ship simulation scenarios, such as resistance prediction, ship flow modelling, self-propulsion, and cavitation analyses. It is expected that the present paper will provide decision-making support by helping CFD users minimise the time spent on trial and error, as well as providing valuable insights to promote the advancement of turbulence modelling

    Wave-GAN: A deep learning approach for the prediction of nonlinear regular wave loads and run-up on a fixed cylinder

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    Machine learning techniques have inspired reduced-order solutions in the fluid mechanics field that show benefits of unprecedented capability and efficiency. Targeting ocean-wave problems, this work has developed a novel data-driven computational approach, named Wave-GAN. This new tool is based upon the conditional Generative Adversarial Network (GAN) principle, and it provides the ability to predict three-dimensional nonlinear wave loads and run-up on a fixed structure. The paper presents the principle of Wave-GAN and an application example of regular waves interacting with a vertical fixed cylinder. Computational Fluid Dynamics (CFD) is used to provide training and testing datasets for the Wave-GAN deep learning network. Upon verification, Wave-GAN proved the ability to provide accurate results for predicting wave load and run-up for wave conditions that were not informed during training. Yet the CFD-comparative results were only obtained within seconds by the deep learning tool. The promising results demonstrate Wave-GAN's outstanding potential to act as a pioneering sample of applying machine learning techniques to wave-structural interaction problems. It is envisioned that the new approach could be extended to more complex shapes and wave conditions to facilitate the various design stages of marine and offshore engineering applications such as monopiles. As a result, enhanced reliability is expected to optimise structural performance and prevent environmental disasters

    Biomimetics in Ship Design?

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    The hydrodynamic performance of ships can be improved by the retrofit of Energy Saving Devices (ESDs). These devices are typically seen in the aft part of the ship hull and act by lowering the ship resistance, conditioning the fluid in front of the propeller and/or recovering energy from the rotational swirl of the fluid leaving the propeller. Technological gaps in the field suggested that there is a room for the development of a new biomimetic ESD based on ‘tubercles’ technology. Tubercles are rounded structures naturally found on the leading edge of the Humpback’s whale flipper and they are capable to hydrodynamically control the flow around the whale. Similarly, a novel device has been created to control the flow around the aft part of the hull, reducing ship’s resistance and improving the wake conditions in which the propeller operates. This research paper presents tubercles technology, working principles and the results from the first numerical experiments of a full-scale ship fitted with the created tubercled ESD. The results from this investigation revealed a promising potential of this novel technology

    Electrodeposition of copper using additive-containing low metal ion concentration electrolytes for EnFACE applications

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    In the past decade a new electrodeposition process called Electrochemical nano and micro Fabrication by flow and Chemistry (EnFACE) was developed which enabled mask-less pattern transfers onto a metallic substrate. EnFACE uses a novel acid-free, additive-free plating electrolyte containing low concentrations of metal salts (0.1 MCuSO4), as the process requires electroplating under conditions of fast kinetics and low electrolyte conductivity. However, for electronic applications,industry requires the use of additives, which improve deposit properties such as thickness uniformity, strength, ductility, and conductivity. The use of pulsed current is also known to improve deposit properties such as grain structure, mechanical strength and throwing power. Therefore, in order to use EnFACE for fabrication of industrially useful products, the effect of additives on the electrochemical behaviour and deposit properties of this process needs to be assessed. In addition, the influence of current modulation; i.e. direct current vs pulsed current, on deposit properties also warrants investigation. Potentiodynamic polarisation experiments were performed on additive-free and additive-containing EnFACE electrolyte (0.1 M CuSO₄). The additives tested were Copper Gleam A, Copper Gleam B, and chloride ions (Cl⁻). The effect of two parameters: (i) additive type and (ii) additive concentration, on cathode polarisation were studied.Copper films were electroplated on stainless steel substrates from electrolytes containing different concentrations of plating additives (0%, 17%, 33%, 50%, 100%,200% of the industry recommended additive concentration). Both direct current (DC)ABSTRACT|ii and pulsed current (PC) plating were used. The deposit was characterised using scanning electron microscope (SEM), electron back scattered diffraction (EBSD),tensile test machine (UTM), four-point probe and X-ray diffraction (XRD).Cathode polarisation occurred when the additives were used individually. Thecombination of Copper Gleam B and Cl- suggested synergistic inhibition, particularly in the diffusion-limited region. The addition of Copper Gleam A to the CopperGleam B-Cl⁻ mix increased the limiting current and suggested plating acceleration.These effects are interpreted in terms of the adsorption-desorption behavior of the additives on the cathode surface. SEM and EBSD images indicated that additives caused a concentration dependent decrease in the grain size of the deposit in both the DC and PC plated deposit. This grain refinement resulted in an increase in yield and tensile strength,but reduced the ductility and resistivity of deposits. The PC-plated copper from theEnFACE electrolytes generally possessed better mechanical properties than its DC-plated counterparts, though both plating modes created copper films that can meet industry standards. The optimum additive concentration for the EnFACE electrolyte was 50% of the recommended value when using DC plating; while the optimum was only 33% when using PC plating.In the past decade a new electrodeposition process called Electrochemical nano and micro Fabrication by flow and Chemistry (EnFACE) was developed which enabled mask-less pattern transfers onto a metallic substrate. EnFACE uses a novel acid-free, additive-free plating electrolyte containing low concentrations of metal salts (0.1 MCuSO4), as the process requires electroplating under conditions of fast kinetics and low electrolyte conductivity. However, for electronic applications,industry requires the use of additives, which improve deposit properties such as thickness uniformity, strength, ductility, and conductivity. The use of pulsed current is also known to improve deposit properties such as grain structure, mechanical strength and throwing power. Therefore, in order to use EnFACE for fabrication of industrially useful products, the effect of additives on the electrochemical behaviour and deposit properties of this process needs to be assessed. In addition, the influence of current modulation; i.e. direct current vs pulsed current, on deposit properties also warrants investigation. Potentiodynamic polarisation experiments were performed on additive-free and additive-containing EnFACE electrolyte (0.1 M CuSO₄). The additives tested were Copper Gleam A, Copper Gleam B, and chloride ions (Cl⁻). The effect of two parameters: (i) additive type and (ii) additive concentration, on cathode polarisation were studied.Copper films were electroplated on stainless steel substrates from electrolytes containing different concentrations of plating additives (0%, 17%, 33%, 50%, 100%,200% of the industry recommended additive concentration). Both direct current (DC)ABSTRACT|ii and pulsed current (PC) plating were used. The deposit was characterised using scanning electron microscope (SEM), electron back scattered diffraction (EBSD),tensile test machine (UTM), four-point probe and X-ray diffraction (XRD).Cathode polarisation occurred when the additives were used individually. Thecombination of Copper Gleam B and Cl- suggested synergistic inhibition, particularly in the diffusion-limited region. The addition of Copper Gleam A to the CopperGleam B-Cl⁻ mix increased the limiting current and suggested plating acceleration.These effects are interpreted in terms of the adsorption-desorption behavior of the additives on the cathode surface. SEM and EBSD images indicated that additives caused a concentration dependent decrease in the grain size of the deposit in both the DC and PC plated deposit. This grain refinement resulted in an increase in yield and tensile strength,but reduced the ductility and resistivity of deposits. The PC-plated copper from theEnFACE electrolytes generally possessed better mechanical properties than its DC-plated counterparts, though both plating modes created copper films that can meet industry standards. The optimum additive concentration for the EnFACE electrolyte was 50% of the recommended value when using DC plating; while the optimum was only 33% when using PC plating

    A non-resonant dark-side solution to the solar neutrino problem

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    We re-analyse spin-flavour precession solutions to the solar neutrino problem in the light of the recent SNO CC result as well as the 1258--day Super-Kamiokande data and the upper limit on solar anti-neutrinos. In a self-consistent magneto-hydrodynamics approach the resulting scheme has only 3 effective parameters: Δm2\Delta m^2, ÎŒB⊄\mu B_\perp and the neutrino mixing angle Ξ\theta. We show how a rates-only analysis for fixed ÎŒB⊄\mu B_\perp slightly favours spin-flavour precession (SFP) solutions over oscillations (OSC). In addition to the resonant solution (RSFP for short), there is a new non-resonant solution (NRSFP) in the ``dark-side''. Both RSFP and NRSFP lead to flat recoil energy spectra in excellent agreement with the latest SuperKamiokande data. We also show that in the presence of a neutrino transition magnetic moment of 10−1110^{-11} Bohr magneton, a magnetic field of 80 KGauss eliminates all large mixing solutions other than the so-called LMA solution.Comment: 12 pages, 3 postscript figures, using elsart.cls. Published versio
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