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51. The Cause and Duration of Emergency Admissions to Hospital in People with Idiopathic Parkinson's Disease, Under the Care of a UK Service, During the First Year of the COVID-19 Pandemic.

Author

Ellis, Penelope K., Davies, Matthew L., Gray, William K., Barber, Margaret, Bolnykh, Ifkov, Sadler, Molly, and Walker, Richard W.

Subjects
*PARKINSON'S disease, *HOSPITAL admission & discharge, *COVID-19 pandemic, *HOSPITAL emergency services, *MEDICAL audit
Abstract

Background: People with Parkinson's disease (PD) have higher rates of hospitalisation and healthcare utilisation compared to the general population. The COVID-19 pandemic caused significant changes in admissions to hospital and access to healthcare. People with PD are some of the most vulnerable to such changes. There is no pre-existing data on the cause and duration of admission to hospital of people with PD during the COVID-19 pandemic. Objective: To determine the cause, duration, and outcome of hospital admissions to Northumbria Healthcare NHS Foundation Trust (NHCFT) for people with idiopathic Parkinson's disease (IPD) in 2020. Methods: All people with IPD who had an emergency admission to NHCFT between 01/01/2020 and 31/12/2020 were identified. Demographic and disease characteristics, the number, duration, cause of admission and the location prior to admission were collected from an audit of medical notes. Results: 271 people with IPD had one or more emergency admissions to NHCFT between 01/01/2020 and 31/12/2020. There was a total of 453 emergency admissions, with a median duration of 5 (IQR 2-13) days. The most common causes of admission to hospital were PD-related motor dysfunction (includes falls with no other underlying cause or associated injury) and injury (includes falls with fracture), at 78 (17.2%) and 70 (15.5%) respectively. Conclusions: People with IPD had a short duration but high number of emergency admissions to hospital. Our chronological data on number of admissions shows a peak in admissions during August 2020. As a result of these findings and emerging data we suggest that individuals with PD deconditioned during 2020. [ABSTRACT FROM AUTHOR]

Published
2022
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53. Spectroscopic study of D1–A–D2–A terpolymer films for optoelectronic applications.

Author

Correa, Roger S., Santos, Bianca P. S., Ribeiro, Arthur C., da Silva, Luiz Alberto F., Péan, Emmanuel V., Davies, Matthew L., Marques, Maria de Fátima V., and Rocco, Maria Luiza M.

Abstract

Several strategies have been considered in search of more efficient organic materials for charge transfer in photovoltaic devices. Among them, the integration of donor–acceptor (D–A) functional units on a conjugated copolymer has been widely applied. In this framework, we evaluated four terpolymers made up of donor moieties derived from 9,9-dioctylfluorene and 9-(heptadecan-9-yl)-9H-carbazole combined with 2,1,3-benzothiadiazole, the acceptor moiety, in different monomer ratios and polymerization routes (block and random microstructures). The preferred molecular orientation and charge transfer dynamics of the polymeric films were assessed by near edge X-ray absorption fine structure spectroscopy (NEXAFS) and resonant Auger electron spectroscopy (RAES) around the sulfur K-edge. Charge transfer times (τCT) were estimated by the Core–Hole Clock (CHC) method. Films with a high degree of organization were identified for the block terpolymer and random terpolymers with uneven amounts of donor units, showing a preferred orientation of the benzothiadiazole (BT) molecular plane parallel to the substrate surface. The values of τCT measured for all terpolymers were higher than those for typical polymers used in photovoltaic devices, which is not desirable for this type of optoelectronic application, but this may be correlated to the strong acceptor character of BT, the unit probed. To investigate the effect of film formation on the excited state behavior, steady-state and time-resolved photoluminescence measurements were also conducted. X-ray photoelectron spectroscopy (XPS) was employed to characterize the surface chemical composition of the terpolymer films. Based on the spectroscopic data the block copolymer appears to be the most suitable for the desired application. [ABSTRACT FROM AUTHOR]

Published
2022
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55. Multiphoton Absorption Stimulated Metal Chalcogenide Quantum Dot Solar Cells under Ambient and Concentrated Irradiance

Author

Hou, Bo, primary, Kim, Byung‐Sung, additional, Lee, Harrison Ka Hin, additional, Cho, Yuljae, additional, Giraud, Paul, additional, Liu, Mengxia, additional, Zhang, Jingchao, additional, Davies, Matthew L., additional, Durrant, James R., additional, Tsoi, Wing Chung, additional, Li, Zhe, additional, Dimitrov, Stoichko D., additional, Sohn, Jung Inn, additional, Cha, SeungNam, additional, and Kim, Jong Min, additional

Published
2020
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64. Interpreting time-resolved photoluminescence of perovskite materials.

Author

Péan, Emmanuel V., Dimitrov, Stoichko, De Castro, Catherine S., and Davies, Matthew L.

Abstract

Time-resolved photoluminescence (TRPL) spectroscopy is a powerful technique to investigate excited charge carrier recombinations in semiconductors and molecular systems. The analysis of the TRPL decays of many molecular systems (e.g. molecules and organic materials) is usually fairly straightfoward and can be fitted with an exponential function allowing extraction of the rate constants. Due to the non-excitonic nature of charge carriers in lead halide perovskite materials coupled with the presence of localised trap states in their band-gap, the TRPL of these materials is much more complicated to interpret. Here we discuss two models used in the literature to simulate charge carrier recombinations and TRPL in perovskites. These models consider the bimolecular nature of direct electron–hole recombination but differ in their treatment of trap-mediated recombination with one model describing trapping as a monomolecular process whereas the other as a bimolecular process between free carriers and the available trap states. In comparison, the classical analysis of perovskite TRPL decay curves (using a sum of exponentials) can lead to misinterpretation. Here we offer some recommendations for meaningful measurements of lead halide perovskite thin-films. The fluence dependence as well as charge carrier accumulation due to incomplete depopulation of all photoexcited carriers between consecutive excitation pulses are discussed for both models. [ABSTRACT FROM AUTHOR]

Published
2020
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67. Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics

Author

Speller, Emily M., primary, McGettrick, James D., additional, Rice, Beth, additional, Telford, Andrew M., additional, Lee, Harrison K. H., additional, Tan, Ching-Hong, additional, De Castro, Catherine S., additional, Davies, Matthew L., additional, Watson, Trystan M., additional, Nelson, Jenny, additional, Durrant, James R., additional, Li, Zhe, additional, and Tsoi, Wing C., additional

Published
2017
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68. Nitrogen/Carbon-Coated Zero-Valent Copper as Highly Efficient Co-catalysts for TiO2Applied in Photocatalytic and Photoelectrocatalytic Hydrogen Production

Author

Ombaka, Lucy M., Curti, Mariano, McGettrick, James D., Davies, Matthew L., and Bahnemann, Detlef W.

Abstract

Zero-valent copper (Cu0) is a promising co-catalyst in semiconductor-based photocatalysis as it is inexpensive and exhibits electronic properties similar to those of Ag and Au. However, its practical application in photocatalytic hydrogen production is limited by its susceptibility to oxidation, forming less active Cu species. Herein, we have carried out in situencapsulation of Cu0nanoparticles with N-graphitic carbon layers (14.4% N) to stabilize Cu0nanoparticles (N/C-coated Cu) and improve the electronic communication with a TiO2photocatalyst. A facile solvothermal procedure is used to coat the Cu0nanoparticles at 200 °C, while graphitization is achieved by calcination at 550 °C under an inert atmosphere. The resultant N/C-coated Cu/TiO2composites outperform the uncoated Cu counterparts, exhibiting a 27-fold enhancement of the hydrogen evolution rate compared to TiO2and achieving a rate of 19.03 mmol g–1h–1under UV–vis irradiation. Likewise, the N/C-coated Cu co-catalyst exhibits a less negative onset potential of −0.05 V toward hydrogen evolution compared to uncoated Cu (ca. −0.30 V). This superior activity is attributed to coating Cu0with N/C, which enhances the stability, electronic communication with TiO2, conductivity, and interfacial charge transfer processes. The reported synthetic approach is simple and scalable, yielding an efficient and affordable Cu0co-catalyst for TiO2.

Published
2020
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70. Improving the light harvesting and colour range of methyl ammonium lead tri-bromide (MAPbBr3) perovskite solar cells through co-sensitisation with organic dyes.

Author

McFarlane, Tamara D., De Castro, Catherine S., Holliman, Peter J., and Davies, Matthew L.

Subjects
METHYLAMMONIUM, PEROVSKITE, SOLAR cells
Abstract

Co-sensitisation of methylammonium lead tri-bromide perovskite solar cells with red (D205) and blue (SQ2) organic dyes improves device efficiencies and allows device colour tuning. Sensitising the film after perovskite crystallisation produces higher device efficiencies (2.6% SQ2, 3.1% D205) than perovskite-only devices (2%) and devices sensitised before the perovskite layer deposition (1.5% SQ2, 2.0% D205). [ABSTRACT FROM AUTHOR]

Published
2019
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71. Detailed Sunyaev–Zel’dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius

Author

Rodríguez-Gonzálvez, Carmen, Shimwell, Timothy W., Davies, Matthew L., Feroz, Farhan, Franzen, Thomas M. O., Grainge, Keith J. B., Hobson, Michael P., Hurley-Walker, Natasha, Lasenby, Anthony N., Olamaie, Malak, Pooley, Guy, Saunders, Richard D. E., Scaife, Anna M. M., Schammel, Michel P., Scott, Paul F., Titterington, David J., and Waldram, Elizabeth M.

Abstract

We present detailed 16-GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with L_X > 7 × 10^(37) W (h_(50) = 1) selected from the Local Cluster Substructure Survey (LoCuSS; 0.142 ≤ z ≤ 0.295) and of Abell 1758b, which is in the field of view of Abell 1758a. We detect and resolve Sunyaev–Zel'dovich (SZ) signals towards 17 clusters, with peak surface brightnesses between 5σ and 23σ. We use a fast, Bayesian cluster analysis to obtain cluster parameter estimates in the presence of radio point sources, receiver noise and primordial cosmic microwave background (CMB) anisotropy. We fit isothermal β-models to our data and assume the clusters are virialized (with all the kinetic energy in gas internal energy). Our gas temperature, T_(AMI), is derived from AMI SZ data and not from X-ray spectroscopy. Cluster parameters internal to r_(500) are derived under the assumption of hydrostatic equilibrium. We find the following. (i) Different generalized Navarro–Frenk–White (gNFW) parametrizations yield significantly different parameter degeneracies. (ii) For h_(70) = 1, we find the classical virial radius, r_(200), to be typically 1.6 ± 0.1 Mpc and the total mass M_T(r_(200)) typically to be 2.0–2.5× M_T(r_(500)). (iii) Where we have found M_T(r_(500)) and M_T(r_(200)) X-ray and weak-lensing values in the literature, there is good agreement between weak-lensing and AMI estimates (with M_(T,AMI)/M_(T,WL) = 1.2^(+0.2)_(−0.3) and 1.0 ± 0.1 for r_(500) and r_(200), respectively). In comparison, most Suzaku/Chandra estimates are higher than for AMI (with M_(T,X)/M_(T,AMI) = 1.7 ± 0.2 within r_(500)), particularly for the stronger mergers. (iv) Comparison of T_(AMI) to T_X sheds light on high X-ray masses: even at large radius, T_X can substantially exceed T_(AMI) in mergers. The use of these higher T_X values will give higher X-ray masses. We stress that large-radius T_(AMI) and T_X data are scarce and must be increased. (v) Despite the paucity of data, there is an indication of a relation between merger activity and SZ ellipticity. (vi) At small radius (but away from any cooling flow) the SZ signal (and T_(AMI)) is less sensitive to intracluster medium disturbance than the X-ray signal (and T_X) and, even at high radius, mergers affect n^2-weighted X-ray data more than n-weighted SZ, implying that significant shocking or clumping or both occur in even the outer parts of mergers.

Published
2012

77. Synthesis, spectroscopy, photophysics and thermal behaviour of stilbene-based triarylamines with dehydroabietic acid methyl ester moieties

Author

Gigante, Bárbara, Esteves, M. Alexandra, Pires, N., Davies, Matthew L., Douglas, Peter, Fonseca, Sofia M., Burrows, Hugh D., Pina, João, and Melo, João Seixas de

Abstract

Novel stilbene-based triarylamines with dehydroabietic acid methyl ester moieties have been synthesised by palladium catalysed C–N coupling reactions. The presence of the bulky dehydroabietic acid group increases solubility, hinders crystallisation and permits their sublimation while preserving their electronic and optical characteristics. This makes them good candidates for various molecular electronic applications. We report a detailed characterisation of their electrochemical, spectroscopic and photophysical properties. In addition, the thermal stability and behaviour is discussed with reference to the potential for preparation of stable thin films.

Published
2009

78. Do DNA and Guanine Quench Fluorescence of Conjugated Cationic Polymers by Induced Aggregation?

Author

Davies,Matthew L., Douglas,Peter, Burrows,Hugh D., Miguel,M. Graça, and Douglas,Alastair

Subjects
energy migration, quenching, aggregation, guanine, DNA, cationic conjugated polyelectrolytes
Abstract

DNA and guanine are efficient fluorescence quenchers of the cationic conjugated polymer, poly {9,9-bis[N,N-(trimethylammonium)hexyl] fluorene-co-l,4-phenylene} (CCP). Studies with CCPs, of average chain length ~6, 12 and 100 repeat units, with single strand (ss) DNA, double strand (ds) DNA, and guanine, in 25/75 acetonitrile/water (v/v) mixtures result in Stern-Volmer quenching plots that show upward curvature. Initial Stern-Volmer constants, kSV, are in the range ≈ 3-20 x 10(7) M-1 which is much higher than possible by diffusional encounter quenching. Aggregation studies in acetonitrile/water mixtures show that aggregation is also an effective quencher of CCP fluorescence, and we note that both aggregation and quenching by DNA or guanine is accompanied by a reduction in solution absorbance at 380 nm. Comparison of the relationship between changes in absorbance and changes in emission intensity suggest that both solvent and chemical induced fluorescence quenching are due to aggregation. We interpret the correlated changes in absorption and emission, high quenching constants, and upward curving Stern-Volmer plots as evidence that the dominant mechanism for fluorescence quenching by DNA or guanine is via induced aggregation of the polymer. The upward curvature of Stern- Volmer plots and high kSV values for DNA and guanine are indicative of “aggregate energy migration quenching” in which CCP aggregates around a DNA or guanine molecule to form an aggregate complex in which excitation energy migrates between and along the polymer chains until it is quenched at an aggregate trap.

Published
2009

82. An effective approach of vapour assisted morphological tailoring for reducing metal defect sites in lead-free, (CH3NH3)3Bi2I9bismuth-based perovskite solar cells for improved performance and long-term stability

Author

Jain, Sagar M., Phuyal, Dibya, Davies, Matthew L., Li, Meng, Philippe, Bertrand, De Castro, Catherine, Qiu, Zhen, Kim, Jinhyun, Watson, Trystan, Tsoi, Wing Chung, Karis, Olof, Rensmo, Håkan, Boschloo, Gerrit, Edvinsson, Tomas, and Durrant, James R.

Abstract

We present a controlled, stepwise formation of methylammonium bismuth iodide (CH3NH3)3Bi2I9perovskite films prepared via the vapour assisted solution process (VASP) by exposing BiI3films to CH3NH3I (MAI) vapours for different reaction times, (CH3NH3)3Bi2I9semiconductor films with tunable optoelectronic properties are obtained. Solar cells prepared on mesoporous TiO2substrates yielded hysteresis-free efficiencies upto 3.17% with good reproducibility. The good performance is attributed mainly to the homogeneous surface coverage, improved stoichiometry, reduced metallic content in the bulk, and desired optoelectronic properties of the absorbing material. In addition, solar cells prepared using pure BiI3films without MAI exposure achieved a power conversion efficiency of 0.34%. The non-encapsulated (CH3NH3)3Bi2I9devices were found to be stable for as long as 60 days with only 0.1% drop in efficiency. This controlled formation of (CH3NH3)3Bi2I9perovskite films highlights the benefit of the VASP technique to optimize material stoichiometry, morphology, solar cell performance, and long-term durability.

Published
2018
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93. Ultra-fast co-sensitization and tri-sensitization of dye-sensitized solar cells with N719, SQ1 and triarylamine dyes

Author

Holliman, Peter J., primary, Mohsen, Moneer, additional, Connell, Arthur, additional, Davies, Matthew L., additional, Al-Salihi, Kareem, additional, Pitak, Mateusz B., additional, Tizzard, Graham J., additional, Coles, Simon J., additional, Harrington, Ross W., additional, Clegg, William, additional, Serpa, Carlos, additional, Fontes, Octávio H., additional, Charbonneau, Cecile, additional, and Carnie, Matthew J., additional

Published
2012
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94. Sunyaev-Zel’dovich observations of galaxy clusters out to the virial radius with the Arcminute Microkelvin Imager★

Author

Zwart, Jonathan T. L., primary, Feroz, Farhan, additional, Davies, Matthew L., additional, Franzen, Thomas M. O., additional, Grainge, Keith J. B., additional, Hobson, Michael P., additional, Hurley-Walker, Natasha, additional, Kneissl, Rüdiger, additional, Lasenby, Anthony N., additional, Olamaie, Malak, additional, Pooley, Guy G., additional, Rodríguez-Gonzálvez, Carmen, additional, Saunders, Richard D. E., additional, Scaife, Anna M. M., additional, Scott, Paul F., additional, Shimwell, Timothy W., additional, Titterington, David J., additional, and Waldram, Elizabeth M., additional

Published
2011
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96. Microwave observations of spinning dust emission in NGC6946⋆

Author

Scaife, Anna M. M., primary, Nikolic, Bojan, additional, Green, David A., additional, Beck, Rainer, additional, Davies, Matthew L., additional, Franzen, Thomas M. O., additional, Grainge, Keith J. B., additional, Hobson, Michael P., additional, Hurley-Walker, Natasha, additional, Lasenby, Anthony N., additional, Olamaie, Malak, additional, Pooley, Guy G., additional, Rodríguez-Gonzálvez, Carmen, additional, Saunders, Richard D. E., additional, Scott, Paul F., additional, Shimwell, Timothy W., additional, Titterington, David J., additional, Waldram, Elizabeth M., additional, and Zwart, Jonathan T. L., additional

Published
2010
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97. High-resolution AMI Large Array imaging of spinning dust sources: spatially correlated 8 μm emission and evidence of a stellar wind in L675

Author

Scaife, Anna M. M., primary, Green, David A., additional, Pooley, Guy G., additional, Davies, Matthew L., additional, Franzen, Thomas M. O., additional, Grainge, Keith J. B., additional, Hobson, Michael P., additional, Hurley-Walker, Natasha, additional, Lasenby, Anthony N., additional, Olamaie, Malak, additional, Richer, John S., additional, Rodríguez-Gonzálvez, Carmen, additional, Saunders, Richard D. E., additional, Scott, Paul F., additional, Shimwell, Timothy W., additional, Titterington, David J., additional, Waldram, Elizabeth M., additional, and Zwart, Jonathan T. L., additional

Published
2010
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99. Follow-up observations at 16 and 33���GHz of extragalactic sources fromWMAP3-yr data: II ��� Flux density variability

Author

Franzen, Thomas M. O., primary, Davies, Matthew L., additional, Davies, Rod D., additional, Davis, Richard J., additional, Feroz, Farhan, additional, G��nova-Santos, Ricardo, additional, Grainge, Keith J. B., additional, Green, David A., additional, Hobson, Michael P., additional, Hurley-Walker, Natasha, additional, Lasenby, Anthony N., additional, L��pez-Caniego, Marcos, additional, Olamaie, Malak, additional, Padilla-Torres, Carmen P., additional, Pooley, Guy G., additional, Rebolo, Rafael, additional, Rodr��guez-Gonz��lvez, Carmen, additional, Saunders, Richard D. E., additional, Scaife, Anna M. M., additional, Scott, Paul F., additional, Shimwell, Timothy W., additional, Titterington, David J., additional, Waldram, Elizabeth M., additional, Watson, Robert A., additional, and Zwart, Jonathan T. L., additional

Published
2009
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100. Follow-up observations at 16 and 33���GHz of extragalactic sources fromWMAP3-yr data: I ��� Spectral properties

Author

Davies, Matthew L., primary, Franzen, Thomas M. O., additional, Davies, Rod D., additional, Davis, Richard J., additional, Feroz, Farhan, additional, G��nova-Santos, Ricardo, additional, Grainge, Keith J. B., additional, Green, David A., additional, Hobson, Michael P., additional, Hurley-Walker, Natasha, additional, Lasenby, Anthony N., additional, L��pez-Caniego, Marcos, additional, Olamaie, Malak, additional, Padilla-Torres, Carmen P., additional, Pooley, Guy G., additional, Rebolo, Rafael, additional, Rodr��guez-Gonz��lvez, Carmen, additional, Saunders, Richard D. E., additional, Scaife, Anna M. M., additional, Scott, Paul F., additional, Shimwell, Timothy W., additional, Titterington, David J., additional, Waldram, Elizabeth M., additional, Watson, Robert A., additional, and Zwart, Jonathan T. L., additional

Published
2009
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