Now showing items 21-40 of 7732

    • Frequency Reconfigurable Antenna Array for MM-Wave 5G Mobile Handsets

      Ojaroudi Parchin, Naser; Al-Yasir, Yasir; Abdulkhaleq, Ahmed M.; Elfergani, I.; Rayit, A.; Noras, James M.; Rodriguez, Jonathan; Abd-Alhameed, Raed A. (2018-09-20)
      This study proposes a compact design of frequency-reconfigurable antenna array for fifth generation (5G) cellular networks. Eight compact discrete- fed slot antennas are placed on the top portion of a mobile phone printedcircuit- board (PCB) to form a beam-steerable array. The frequency response of the antenna can be reconfigured to operate at either 28 GHz or 38 GHz, two of the candidate frequency bands for millimeter-wave (MM-Wave) 5G communications. The reconfigurability function of the proposed design can be achieved by implementing and biasing a pair of diodes across each T-shaped slot antenna element. Rogers RT 5880 with thickness of 0.508 mm and properties of ε = 2.2 and δ = 0.0009 has been used as the antenna substrate. The antenna element is very compact in size with a good end-fire radiation pattern in the frequency bands of interest. The proposed beam-steerable array provides very good 3D coverage. The simulation results show that the proposed design provides some good characteristics fitting the need of the 5G cellular communications.
    • A New Polarization-Reconfigurable Antenna for 5G Wireless Communications

      Al-Yasir, Yasir; Ojaroudi Parchin, Naser; Elfergani, I.; Abd-Alhameed, Raed A.; Noras, James M.; Rodriguez, Jonathan; Al-jzari, A.; Hammed, W.I. (2018-09-20)
      This paper presents a circular polarization reconfigurable antenna for 5G applications, which is compact in size and has good axial ratio and frequency response. The proposed microstrip antenna is designed on a FR-4 substrate with a relative dielectric constant of 4.3 and has a maximum size of 30×30 mm2 with 50 Ω coaxial probe feeding. This design has two PIN diode switches controlling reconfiguration between right hand circular polarization (RHCP) and left hand circular polarization (LHCP). To achieve reconfigurability, a C-slot rectangular patch antenna with truncated corner techniques is employed by cutting off two corners on the radiating patch. The proposed antenna has been simulated using CST microwave studio software: it has 3.35-3.77 GHz and 3.4-3.72 GHz bands for both states of reconfiguration, and each is suitable for 5G applications with a good axial ratio of less than 1.8 dB and good gain of 4.8 dB for both modes of operation.
    • Preventing chemical weapons as sciences converge

      Crowley, Michael J.A.; Shang, Lijun; Dando, Malcolm R. (2018-11)
      Stark illustrations of the dangers from chemical weapons can be seen in attacks using toxic industrial chemicals and sarin against civilians and combatants in Syria and toxic industrial chemicals in Iraq, as well as more targeted assassination operations in Malaysia and the United Kingdom, employing VX and novichok nerve agents, respectively. Concerns about such malign applications of chemical technology are exacerbated by the unstable international security environment and the changing nature of armed conflict, “where borderlines between war, civil war, large-scale violations of human rights, revolutions and uprisings, insurgencies and terrorism as well as organized crime are blurred” (1). It is thus essential that the global community regularly review the nature and implications of developments in chemistry, and its convergence with the life and associated sciences, and establish appropriate measures to prevent their misuse. With the parties to the Chemical Weapons Convention (CWC) convening a Review Conference to address such issues beginning 21 November 2018, we highlight important scientific aspects (2)
    • The Performance of SLNR Beamformers in Multi-User MIMO Systems

      Hameed, Khalid W.H.; Abdulkhaleq, Ahmed M.; Al-Yasir, Yasir; Ojaroudi Parchin, Naser; Rayit, A.; Al Khambashi, M.; Abd-Alhameed, Raed A.; Noras, James M. (2018-09-20)
      Beamforming in multi-user MIMO (MU-MIMO) systems is a vital part of modern wireless communication systems. Researchers looking for best operational performance normally optimize the problem and then solve for best weight solutions. The weight optimization problem contains variables in numerator and dominator: this leads to so-called variable coupling, making the problem hard to solve. Formulating the optimization in terms of the signal to leakage and noise ratio (SLNR) helps in decoupling the problem variables. In this paper we study the performance of the SLNR with variable numbers of users and handset antennas. The results show that there is an optimum and the capacity curve is a concave over these two parameters. The performances of two further variations of this method are also considered.
    • The impact of comorbidity on the quality of life of people with dementia: findings from the IDEAL study

      Nelis, S.M.; Wu, Y-T.; Matthews, F.E.; Martyr, A.; Quinn, Catherine; Rippon, I.; Rusted, J.; Thom, J.M.; Kopelman, M.D.; Hindle, J.V.; Jones, R.W.; Clare, L. (2018)
      Background: The aim was to investigate the comorbidity profile of people with dementia and examine the associations between severity of comorbidity, health-related quality of life (HRQoL) and quality of life (QoL). Methods: The improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort consisted of 1,547 people diagnosed with dementia who provided information on the number and type of comorbid conditions. Participants also provided ratings of their health-related and dementia-specific QoL. Results: The majority of the sample were living with more than one chronic condition. Hypertension was commonly reported and frequently combined with connective tissue disease, diabetes and depression. The number of comorbid conditions was associated with low QoL scores, and those with severe comorbidity (≥5 conditions) showed the greatest impact on their well-being. Conclusions: Comorbidity is an important risk factor for poor QoL and health status in people with dementia. Greater recognition of the nature and impact of comorbidity is needed to inform support and interventions for people with dementia and a multidisciplinary approach to care provision is recommended.
    • Protocol for the IDEAL-2 longitudinal study: following the experiences of people with dementia and their primary carers to understand what contributes to living well with dementia and enhances active life

      Silarova, B.; Nelis, S.M.; Ashworth, R.M.; Ballard, C.; Bienkiewicz, M.; Henderson, C.; Hillman, A.; Hindle, J.V.; Hughes, J.C.; Lamont, R.A.; Litherland, R.; Jones, I.R.; Jones, R.W.; Knapp, M.; Kotting, P.; Martyr, A.; Matthews, F.E.; Morris, R.G.; Quinn, Catherine; Regan, J.; Rusted, J.M.; van den Heuval, E.A.; Victor, C.R.; Wu, Y-T.; Clare, L. (2018-10)
      Background: There is a major need for longitudinal research examining the experiences of people with dementia and their primary carers, as relatively little is known about how the factors associated with capability to ‘live well’ vary over time. The main aim of the IDEAL-2 study is to investigate how and why, over time, people with dementia and their primary carers might vary in their capability to live well with dementia, whilst exploring both their use of health and care services and their unmet needs. Methods: IDEAL-2 will build on the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort of 1547 people (who, at recruitment between July 2014 and July 2016, had mild-to-moderate dementia), and their 1283 primary carers in Great Britain. The existing cohort will be enriched with additional participants with mild-to-moderate dementia (and their primary carers where available and willing) from the following groups: people with rarer forms of dementia, and/or those who are ≥90 years or < 65 years of age at time of recruitment. We will assess the primary outcome, capability to live well with dementia, and the factors influencing it using questionnaires at yearly intervals for 3 years. Additionally, we will seek to link the cohort data with administrative data to obtain information about health service use. Some participants will be invited for in-depth face-to-face interviews. The cohort study will be supplemented by linked research focusing on: the co-production of new measures of living well; including the perspectives of people with advanced dementia living in residential care settings; including people with dementia from black, Asian, and minority ethnic groups; and understanding the experience of people living with undiagnosed dementia. Discussion: IDEAL-2 will provide evidence about the key indicators of, and factors associated with, living well over the course of dementia and how these differ for particular subgroups. It will tell us which combinations of services and support are most beneficial and cost-effective. Moreover, the IDEAL-2 study will gather evidence from underresearched groups of people with dementia, who are likely to have their own distinct perceptions of living well.
    • Reflections on PPI from the ‘Action on Living Well: Asking You’ advisory network of people with dementia and carers as part of the IDEAL study

      Litherland, R.; Burton, J.; Cheeseman, M.; Campbell, D.; Hawkins, M.; Hawkins, T.; Oliver, K.; Scott, D.; Ward, J.; Nelis, S.M.; Quinn, Catherine; Victor, C.; Clare, L. (2018-11-01)
      This article describes the work of the ‘Action on Living Well: Asking You’ group – an involvement group of people with dementia and carers attached to the IDEAL research study. The article describes the work of the group, the methods that have helped them to stay involved and people’s perspectives on their experiences of being involved and the impact it has had, for themselves and others. The article has been written following a reflective piece of work with the ‘Action on Living Well: Asking You’ group to review and remember the work of the past four years. An accompanying film brings to life the work and activities of the group, available at www.idealproject.org.uk/mclass/
    • Modelling the potential for multi-location in-sewer heat recovery at a city scale under different seasonal scenarios

      Mohamad, A-A.; Schellart, A.; Kroll, S.; Mohamed, Mostafa H.A.; Tait, S. (2018)
      A computational network heat transfer model was utilised to model the potential of heat energy recovery at multiple locations from a city scale combined sewer network. The uniqueness of this network model lies in its whole system validation and implementation for seasonal scenarios in a large sewer network. The network model was developed, on the basis of a previous single pipe heat transfer model, to make it suitable for application in large sewer networks and its performance was validated in this study by predicting the wastewater temperature variation in a sewer network. Since heat energy recovery in sewers may impact negatively on wastewater treatment processes, the viability of large scale heat recovery across a network was assessed by examining the distribution of the wastewater temperatures throughout the network and the wastewater temperature at the wastewater treatment plant inlet. The network heat transfer model was applied to a sewer network with around 3000 pipes and a population equivalent of 79500. Three scenarios; winter, spring and summer were modelled to reflect seasonal variations. The model was run on an hourly basis during dry weather. The modelling results indicated that potential heat energy recovery of around 116, 160 & 207 MWh/day may be obtained in January, March and May respectively, without causing wastewater temperature either in the network or at the inlet of the wastewater treatment plant to reach a level that was unacceptable to the water utility.
    • Buried flexible pipes behaviour in unreinforced and reinforced soils under cyclic loading

      Elshesheny, Ahmed; Mohamed, Mostafa H.A.; Sheehan, Therese (2018)
      Because of the recent worldwide construction expansion, new roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Limited research studies are available to assess the effect of geogrid reinforcing layers inclusion on mitigating the additional stresses on buried structures due to cyclic loadings. In this research, large-scale fully instrumented laboratory tests were conducted to investigate the behaviour of flexible High-Density Polyethylene pipes (HDPE), in unreinforced and geogrid-reinforced sand, subjected to incrementally increasing cyclic loading, e.g. due to different vehicles capacities or load increase with passing time. Results illustrated that deformation rate in pipe and footing, strain generation rate in pipe and reinforcing layers are rapidly increased in the initial loading cycles, in particular during the first 300 cycles, and then the rate of change decreases significantly, as more cycles are applied. In the unreinforced case, increasing the pipe burial depth significantly reduced the generated deformation and strain in the pipe; however, it has a situational effect on the footing settlement, where it increased after pipe burial depth to its diameter ratio (H/D) of 2.5. In reinforced cases, deformation and strain significantly reduced with the increase in pipe burial depth and number of reinforcing layers. Measurement of strain illustrated that strain generated in the lower reinforcing layer is always higher than that recorded in the upper one, regardless pipe burial depth and value of applied load.
    • Object registration in semi-cluttered and partial-occluded scenes for augmented reality

      Gao, Q.H.; Wan, Tao Ruan; Tang, W.; Chen, L. (2018)
      This paper proposes a stable and accurate object registration pipeline for markerless augmented reality applications. We present two novel algorithms for object recognition and matching to improve the registration accuracy from model to scene transformation via point cloud fusion. Whilst the first algorithm effectively deals with simple scenes with few object occlusions, the second algorithm handles cluttered scenes with partial occlusions for robust real-time object recognition and matching. The computational framework includes a locally supported Gaussian weight function to enable repeatable detection of 3D descriptors. We apply a bilateral filtering and outlier removal to preserve edges of point cloud and remove some interference points in order to increase matching accuracy. Extensive experiments have been carried to compare the proposed algorithms with four most used methods. Results show improved performance of the algorithms in terms of computational speed, camera tracking and object matching errors in semi-cluttered and partial-occluded scenes.
    • Linear free energy relationship analysis of permeability across polydimethylsiloxane (PDMS) membranes and comparison with human skin permeation in vitro

      Liu, Xiangli; Zhang, K.; Abraham, M.H. (2018-10-15)
      The aim of the present work is to evaluate the similarity between PDMS membranes and human skin in vitro in permeation study by linear free energy relationship (LFER) analyses. The values of the permeability coefficient log Kp (cm/s) under reliable experimental conditions were collected from the literature for a set of 94 compounds including both neutral and ionic species, which cover a broad range of structural diversity. The values of log Kp (cm/s) have been correlated with Abraham descriptors to yield an equation with R2 = 0.952 and SD = 0.38 log units. The established LFER model for log Kp (cm/s) across PDMS membranes showed no close analogy with that through human skin in vitro. A further critical analysis of the coefficients of the LFER models confirmed that the PDMS permeation system is a very poor model for human skin permeation.
    • Impact of body part thickness on AP pelvis radiographic image quality and effective dose

      Alzyoud, K.; Hogg, P.; Snaith, Beverly; Flintham, K.; England, A. (2018-10-03)
      Introduction: Within medical imaging variations in patient size can generate challenges, especially when selecting appropriate acquisition parameters. This experiment sought to evaluate the impact of increasing body part thickness on image quality (IQ) and effective dose (E) and identify optimum exposure parameters. Methods: An anthropomorphic pelvis phantom was imaged with additional layers (1e15 cm) of animal fat as a proxy for increasing body thickness. Acquisitions used the automatic exposure control (AEC), 100 cm source to image distance (SID) and a range of tube potentials (70e110 kVp). IQ was evaluated physically and perceptually. E was estimated using PCXMC software. Results: For all tube potentials, signal to noise ratio (SNR) and contrast to noise ratio (CNR) deceased as body part thickness increased. 70 kVp produced the highest SNR (46.6e22.6); CNR (42.8e17.6). Visual grading showed that the highest IQ scores were achieved using 70 and 75 kVp. As thickness increases, E increased exponentially (r ¼ 0.96; p < 0.001). Correlations were found between visual and physical IQ (SNR r ¼ 0.97, p < 0.001; CNR r ¼ 0.98, p < 0.001). Conclusion: To achieve an optimal IQ across the range of thicknesses, lower kVp settings were most effective. This is at variance with professional practice as there is a tendency for radiographers to increase kVp as thickness increases. Dose reductions were experienced at higher kVp settings and are a valid method for optimisation when imaging larger patients.
    • Predicting the skin-permeating components of externally-applied medicinal herbs: application of a newly constructed linear free-energy relationship equation for human skin permeation

      Zeng, X.; Wang, Z.; Liu, Xiangli; Chen, M.; Fahr, A.; Zhang, K. (2018-06)
      A linear free-energy relationship (LFER) equation that is able to provide a valid prediction of the skin permeability coefficients (log Kp) of neutral molecules, ions and ionic species has recently been constructed and optimized. This study aimed to evaluate the feasibility of predicting the skin-permeating components (SPCs) of externally applied herbs using the LFER equation, with Evodiae fructus (EF) taken as a model herb. The log Kp values of the reported chemical components of EF at pH 4.0 were calculated using the LFER equation and their structural descriptors. The results showed that the essential oils, quinolone, acridone and indole alkaloids of EF are more permeable when compared to other main components, such as phenylpropanoids, furoquinoline alkaloids, limonoids and flavonoids. The SPCs of EF were further collected via ex vivo skin permeation experiments, and analyzed by liquid chromatography-high resolution tandem mass spectrometry. A total of 80 SPCs were detected, and part of them were tentatively identified based on their empirical molecular formulae and MS/MS spectra. The SPCs are made up of 58 alkaloids, including 23 or more quinolone alkaloids, 14 or more indole alkaloids and 1 acridone alkaloid, and 22 non-alkaloids, including 7 or more essential oils and 1 flavonoid, which is in good agreement with the prediction by the LFER equation. It is suggested that a log Kp of −7.0 may be considered as a borderline, above which are potential SPCs and below which are non-SPCs. Very interestingly, the primary SPCs give a good explanation to the antihypertensive action of externally applied EF. To sum up, the LFER equation can be used to predict the SPCs of externally applied herbs, and thus to narrow the range of their potential effective components and speed up the pharmacological study.
    • Partition of neutral molecules and ions from water to o-nitrophenyl octyl ether and of neutral molecules from the gas phase to o-nitrophenyl octyl ether

      Abraham, M.H.; Acree Jr, W.E.; Liu, Xiangli (2018-02)
      We have set out an equation for partition of 87 neutral molecules from water to o-nitrophenyl octyl ether, NPOE, an equation for partition of the 87 neutral molecules and 21 ionic species from water to NPOE, and an equation for partition of 87 neutral molecules from the gas phase to NPOE. Comparison with equations for partition into other solvents shows that, as regards partition of neutral (nonelectrolyte) compounds, NPOE would be a good model for 1,2-dichloroethane and for nitrobenzene. In terms of partition of ions and ionic species, NPOE is quite similar to 1,2-dichloroethane and not far away from other aprotic solvents such as nitrobenzene.
    • Perceived tranquility in green urban open spaces

      Marafa, L.M.; Tsang, F.; Watts, Gregory R.; Xu, Y. (2018-08)
      Tranquility has a number of facets. Given the role that tranquility plays in societies, it is increasingly seen as an environmental indicator. Earlier, some have identified tranquility as contributing to health and wellbeing of individuals and the society, making it to be rooted in the context of sound natural ecosystems as a desirable environmental characteristic. Previous studies have identified tranquility places as having links to nature and natural features, wild landscapes, naturally behaving wildlife and natural sounds. The question of how tranquility can be evaluated and the perception of tranquility by visitors is a continuous recurrence. This study therefore selected seven green open spaces in Hong Kong in an attempt to answer these and other questions that are arising. Although results vary, it however provides a perspective on how people perceive tranquil spaces as part of their leisure and recreation indulgence, given rise to the concept of eco-leisure.
    • Fictional first memories

      Akhtar, Shazia; Justice, L.V.; Morrison, Catriona M.; Conway, M.A. (2018)
      In a large-scale survey, 6,641 respondents provided descriptions of their first memory and their age when they encoded that memory, and they completed various memory judgments and ratings. In good agreement with many other studies, where mean age at encoding of earliest memories is usually found to fall somewhere in the first half of the 3rd year of life, the mean age at encoding here was 3.2 years. The established view is that the distribution around mean age at encoding is truncated, with very few or no memories dating to the preverbal period, that is, below about 2 years of age. However, we found that 2,487 first memories (nearly 40% of the entire sample) dated to an age at encoding of 2 years and younger, with 893 dating to 1 year and younger. We discuss how such improbable, fictional first memories could have arisen and contrast them with more probable first memories, those with an age at encoding of 3 years and older.
    • Combined virtual/experimental multicomponent solid forms screening of sildenafil: new salts, cocrystals, and hybrid salt-cocrystals

      Barbas, R.; Font-Bardia, M.; Paradkar, Anant R.; Hunter, C.A.; Prohens, R. (2018)
      New multicomponent solid forms of sildenafil have been discovered by means of a combined virtual/experimental cocrystal screening. Coformer selection of candidates was conducted based on an in silico screening method from a database of more than 2000 organic compounds, and the intensive experimental screen produced 23 new solid forms. Since the 12 coformers chosen have a combination of phenol and carboxylic acid groups, a variety of cocrystals, salts, and hybrid salt-cocrystals were discovered and characterized.
    • The effect of territorial stigmatisation processes on ontological security: A case-study of Bradford politics

      Sullivan, Paul W.; Akhtar, Parveen (2018)
      We investigate the effect of territorial stigmatisation on ontological security through a qualitative case-study of Bradford politics during the 2015 General Election. Territorial stigmatisation and ontological security are important constructs in political geography but there is relatively little research on how territorial stigmatisation effects ontological security in everyday lived experience – in this case, the lived experience of political contests. We conducted thirty in-depth interviews, generated three themes and present and analyse these three themes in the form of three ‘created dialogues’ as outlined by Sullivan (2012), with a smaller sample of ten out of thirty of our participants. Drawing on Bakhtin’s (1981) concept of ‘chronotope’ we identity three key effects of territorial stigmatisation on ontological security: i) A negative reputation of ‘parallel societies’ has the potential to create double meanings for the inhabitants of that society; ii) Local reputation enhances ontological security through linking particular places to particular personalities but potentially decreases ontological security for a district as a whole; iii) Everyday lived experiences sometimes acquire charged emotional symbolic significance, which could encourage the reflexive side of ontological security. Our findings went through a positive member-checking process with five of the participants.
    • Klüver-Bucy Syndrome following traumatic brain injury: a systematic synthesis and review of pharmacological treatment from cases in adolescents and adults

      Clay, F.J.; Kuriakose, A.; Lesche, D.; Hicks, A.J.; Zaman, Hadar; Azizi, E.; Ponsford, J.L.; Jayaram, M.; Hopwood, M. (2018)
      Klüver-Bucy syndrome (KBS) is a rare clinical presentation following traumatic brain injury (TBI). Symptoms include visual agnosia, placidity, hyperorality, sexual hyperactivity, changes in dietary behavior, and hypermetamorphosis. The purpose of this article was to identify and synthesize the available evidence from case reports and case series on the treatment profile of KBS among adolescents and adults after TBI. Four bibliographic databases (MEDLINE OVID, EMBASE, PsycINFO, and SCOPUS) were searched for relevant literature. No date or language restrictions were applied. All case reports containing original data on KBS following TBI among adolescents and adults were included. Articles were evaluated, and data were extracted according to predefined criteria. The literature search identified 24 case reports of KBS post-TBI published between 1968 and 2017. Most case subjects were male (70.1%), and the mean age at injury was 25.1 years (range, 13–67 years). Injury to one or both temporal lobes occurred in most cases. Inappropriate sexual hyperactivity was the most common KBS symptom, followed by a change in dietary behavior and hyperorality. Visual agnosia was the least reported. In 50% of cases, the patient fully recovered from KBS. One-half of all participants described pharmacological management; the most common medication prescribed was carbamazepine. Overall, there was a lack of data available on pharmacotherapy initiation and duration. The complex presentation of KBS presents challenges in terms of treatment options. Although overall individuals who were prescribed carbamazepine had positive outcomes, given the reliance on case reports, it is difficult to make a definitive recommendation to guide clinical practice.