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Impedance Bandwidth Improvement of a Planar Antenna Based on Metamaterial-Inspired T-Matching Network
Get PDFYesIn this paper a metamaterial-inspired T-matching network is directly imbedded inside the feedline of a microstrip antenna to realize optimum power transfer between the front-end of an RF wireless transceiver and the antenna. The proposed T-matching network, which is composed of an arrangement of series capacitor, shunt inductor, series capacitor, exhibits left-handed metamaterial characteristics. The matching network is first theoretically modelled to gain insight of its limitations. It was then implemented directly in the 50-Ω feedline to a standard circular patch antenna, which is an unconventional methodology. The antenna's performance was verified through measurements. With the proposed technique there is 2.7 dBi improvement in the antenna's radiation gain and 12% increase in the efficiency at the center frequency, and this is achieved over a significantly wider frequency range by a factor of approximately twenty. Moreover, there is good correlation between the theoretical model, method of moments simulation, and the measurement results
Bandwidth and gain enhancement of composite right/left-handed metamaterial transmission-line planar antenna employing a non foster impedance matching circuit board
Get PDFYesThe paper demonstrates an effective technique to significantly enhance the bandwidth and radiation gain of an otherwise narrowband composite right/left-handed transmission-line (CRLH-TL) antenna using a non-Foster impedance matching circuit (NF-IMC) without affecting the antenna's stability. This is achieved by using the negative reactance of the NF-IMC to counteract the input capacitance of the antenna. Series capacitance of the CRLH-TL unit-cell is created by etching a dielectric spiral slot inside a rectangular microstrip patch that is grounded through a spiraled microstrip inductance. The overall size of the antenna, including the NF-IMC at its lowest operating frequency is 0.335λ0 × 0.137λ0 × 0.003λ0, where λ0 is the free-space wavelength at 1.4 GHz. The performance of the antenna was verified through actual measurements. The stable bandwidth of the antenna for |S11|≤ - 18 dB is greater than 1 GHz (1.4-2.45 GHz), which is significantly wider than the CRLH-TL antenna without the proposed impedance matching circuit. In addition, with the proposed technique the measured radiation gain and efficiency of the antenna are increased on average by 3.2 dBi and 31.5% over the operating frequency band.RTI2018-095499-B-C31, Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (MCIU/AEI/FEDER,UE), Innovation Programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424 and UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E022936/1
Transcultural identity development among third generation minority consumers
Get PDFYesThis study explores how global and local forces influence the processes of consumer re-acculturation amongst third-generation British Sikhs in the United Kingdom (U.K.). Data is collected over a three-year period using multiple methods that focus on the experiential consumption of shaadi.com by third-generation British-born Sikhs. Data is analysed using thematic analysis, and findings reveal three transcultural identity patterns: accommodating, re-acculturating, and resisting Sikh culture. We argue that the emergent identity patterns are fluid, as our participants feel neither wholly British, wholly Sikh, nor wholly British-Sikh, positioning themselves beyond, rather than against, Sikh or British culture. We uncover the connectedness between the traditional cultural practices of arranged marriages and the space of shaadi.com, a matrimonial website. We interpret this website as a medium through which transcultural identities are constructed. We contribute to theory by showing the development of transcultural patterns of consumption and consistent transcultural identity construction in non-migrating ethnic communities
Triple-layer Tissue Prediction for Cutaneous Skin Burn Injury: Analytical Solution and Parametric Analysis
No full textYesThis paper demonstrates a non-Fourier prediction methodology of triple-layer human skin tissue for determining skin burn injury with non-ideal properties of tissue, metabolism and blood perfusion. The dual-phase lag (DPL) bioheat model is employed and solved using joint integral transform (JIT) through Laplace and Fourier transforms methods. Parametric studies on the effects of skin tissue properties, initial temperature, blood perfusion rate and heat transfer parameters for the thermal response and exposure time of the layers of the skin tissue are carried out. The study demonstrates that the initial tissue temperature, the thermal conductivity of the epidermis and dermis, relaxation time, thermalisation time and convective heat transfer coefficient are critical parameters to examine skin burn injury threshold. The study also shows that thermal conductivity and the blood perfusion rate exhibits negligible effects on the burn injury threshold. The objective of the present study is to support the accurate quantification and assessment of skin burn injury for reliable experimentation, design and optimisation of thermal therapy delivery
Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers
Get PDFYesRapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability
Nanopore sequencing for Mycobacterium tuberculosis: a critical review of the literature, new developments and future opportunities
Get PDFYesThe next-generation short-read sequencing technologies that generate comprehensive, whole-genome data with single-nucleotide resolution have already advanced tuberculosis diagnosis, treatment, surveillance and source investigation. Their high costs, tedious and lengthy processes, and large equipment remain major hurdles for research use in high tuberculosis burden countries and implementation into routine care. The portable next-generation sequencing devices developed by Oxford Nanopore Technologies (ONT) are attractive alternatives due to their long-read sequence capability, compact low-cost hardware, and continued improvements in accuracy and throughput. A systematic review of the published literature demonstrated limited uptake of ONT sequencing in tuberculosis research and clinical care. Of the 12 eligible articles presenting ONT sequencing data on at least one Mycobacterium tuberculosis sample, four addressed software development for long read ONT sequencing data with potential applications for M. tuberculosis. Only eight studies presented results of ONT sequencing of M. tuberculosis, of which five performed whole-genome and three did targeted sequencing. Based on these findings, we summarize the standard processes, reflect on the current limitations of ONT sequencing technology, and the research needed to overcome the main hurdles. Summary: The low capital cost, portable nature and continued improvement in the performance of ONT sequencing make it an attractive option for sequencing for research and clinical care, but limited data is available on its application in the tuberculosis field. Important research investment is needed to unleash the full potential of ONT sequencing for tuberculosis research and care
A Simple Subjective Evaluation of Enface OCT Reflectance Images Distinguishes Glaucoma From Healthy Eyes
Get PDFYesPurpose: We present a subjective approach to detecting glaucomatous defects in
enface images and assess its diagnostic performance. We also test the hypothesis that
if reflectivity changes precede thickness changes in glaucoma there should be reduced
correlation between the modalities in glaucoma compared to controls.
Methods: Twenty glaucoma participants and 20 age-matched controls underwent
high-resolution OCT scans of one eye. 4 μm-thick enface slabs were constructed through
the retina. Enface indices were depths of first gap in visible retinal nerve fiber bundles
(RNFBs) and last visible bundle, subjectively evaluated in six sectors of a 3.5 mm circle
around the optic disc. Retinal nerve fiber layer thickness (RNFLT) along the same circle
was extracted at angles corresponding to enface indices. Between-group differences
were tested by linear mixed models. Diagnostic performance was measured by partial
receiver operating characteristic area (pAUC).
Results: First gap and last visible bundle were closer to the inner limiting membrane in
glaucoma eyes (both P < 0.0001). Enface indices showed excellent diagnostic perfor mance (pAUCs 0.63–1.00), similar to RNFLT (pAUCs 0.63–0.95). Correlation between
enface and RNFLT parameters was strong in healthy (r = 0.81–0.92) and glaucoma eyes
(r = 0.73–0.80).
Conclusions: This simple subjective method reliably identifies glaucomatous defects
in enface images with diagnostic performance at least as good as existing thickness
indices. Thickness and reflectivity were similarly related in healthy and glaucoma eyes,
providing no strong evidence of reflectivity loss preceding thinning. Objective analyses
may realize further potential of enface OCT images in glaucoma.
Translational Relevance: Novel enface OCT indices may aid glaucoma diagnosis
Understanding the principles of non-invasive positive pressure ventilation
No full textNoNon-invasive positive pressure ventilation (NPPV) provides respiratory support to patients without the need for invasive intubation. Although it has been used for several years in critical care, NPPV has come to prominence as a management option for certain patients with respiratory complications of coronavirus disease 2019 (COVID-19). This has led to increased care provision by nurses with little or no experience and expertise in critical care and NPPV. This article provides an overview of the principles of NPPV and its use in type 1 and type 2 respiratory failure. It explains the pathophysiology of several conditions that often lead to respiratory failure and how NPPV can mitigate respiratory failure and improve gas exchange. An individualised assessment of the patient’s suitability for NPPV and an evaluation of the effectiveness of the therapy are crucial to ensure its safe and effective use. Nurses also have an important role in providing explanations and support to patients
Supporting medicines management for older people at care transitions - a theory-based analysis of a systematic review of 24 interventions
No full textYesBackground
Older patients are at severe risk of harm from medicines following a hospital to home transition. Interventions aiming to support successful care transitions by improving medicines management have been implemented. This study aimed to explore which behavioural constructs have previously been targeted by interventions, which individual behaviour change techniques have been included, and which are yet to be trialled.
Method
This study mapped the behaviour change techniques used in 24 randomised controlled trials to the Behaviour Change Technique Taxonomy. Once elicited, techniques were further mapped to the Theoretical Domains Framework to explore which determinants of behaviour change had been targeted, and what gaps, if any existed.
Results
Common behaviour change techniques used were: goals and planning; feedback and monitoring; social support; instruction on behaviour performance; and prompts/cues. These may be valuable when combined in a complex intervention. Interventions mostly mapped to between eight and 10 domains of the Theoretical Domains Framework. Environmental context and resources was an underrepresented domain, which should be considered within future interventions.
Conclusion
This study has identified behaviour change techniques that could be valuable when combined within a complex intervention aiming to support post-discharge medicines management for older people. Whilst many interventions mapped to eight or more determinants of behaviour change, as identified within the Theoretical Domains Framework, careful assessment of the barriers to behaviour change should be conducted prior to intervention design to ensure all appropriate domains are targeted.National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG-0317-20010
What Are the Barriers and Enablers to the Implementation of Pharmacogenetic Testing in Mental Health Care Settings?
Get PDFYesIn psychiatry, the selection of antipsychotics and antidepressants is generally led by a trial-and-error approach. The prescribing of these medications is complicated by sub-optimal efficacy and high rates of adverse drug reactions (ADRs). These both contribute to poor levels of adherence. Pharmacogenetics (PGx) considers how genetic variation can influence an individual’s response to a drug. Pharmacogenetic testing is a tool that could aid clinicians when selecting psychotropic medications, as part of a more personalized approach to prescribing. This may improve the use of and adherence to these medications. Yet to date, the implementation of PGx in mental health environments in the United Kingdom has been slow. This review aims to identify the current barriers and enablers to the implementation of PGx in psychiatry and determine how this can be applied to the uptake of PGx by NHS mental health providers. A systematic searching strategy was developed, and searches were carried out on the PsychInfo, EmBase, and PubMed databases, yielding 11 appropriate papers. Common barriers to the implementation of PGx included cost, concerns over incorporation into current workflow and a lack of knowledge about PGx; whilst frequent enablers included optimism that PGx could lead to precision medicine, reduce ADRs and become a more routine part of psychiatric clinical care. The uptake of PGx in psychiatric care settings in the NHS should consider and overcome these barriers, while looking to capitalize on the enablers identified in this review.Bradford District Care NHS Foundation Trust in partnership with the University of Bradford; National Institute for Health Research (NIHR) Yorkshire and Humber Patient Safety Translational Research Centre (NIHR Yorkshire and Humber PSTRC); National Institute for Health Research Leeds in vitro Diagnostics Co-operative