Cathodoluminescence hyperspectral imaging on the nanometre scale

Extending cathodoluminescence microscopy into the hyperspectral imaging mode brings significant benefits to an already powerful nano-scale characterization tool. In this paper, we give an introduction to the technique, and illustrate its potential with examples of its application to both semiconducting and plasmonic nanostructures

Wide-bandgap halide perovskites for indoor photovoltaics

LJ acknowledges the funding through the UKRI-Future Leaders Fellowship (MR/T022094/1).Indoor photovoltaics (IPVs) are receiving great research attention recently due to their projected application in the huge technology field of Internet of Things (IoT). Among the various existing photovoltaic technologies such as silicon, Cadmium Telluride (CdTe), Copper Indium Gallium Selenide (CIGS), organic photovoltaics, and halide perovskites, the latter are identified as the most promising for indoor light harvesting. This suitability is mainly due to its composition tuning adaptability to engineer the bandgap to match the indoor light spectrum and exceptional optoelectronic properties. Here, in this review, we are summarizing the state-of-the-art research efforts on halide perovskite-based indoor photovoltaics, the effect of composition tuning, and the selection of various functional layer and device architecture onto their power conversion efficiency. We also highlight some of the challenges to be addressed before these halide perovskite IPVs are commercialized.Publisher PDFPeer reviewe

Service evaluation: Three subjective questions that aid in identifying frozen shoulder—Within a multi‐centre musculoskeletal physiotherapy department in primary care

From Crossref journal articles via Jisc Publications RouterHistory: received 2024-04-04, accepted 2024-04-10, epub 2024-04-21, issued 2024-04-21, published 2024-04-21Article version: VoRPublication status: PublishedPrateek Rangra - ORCID: 0000-0002-1457-991X https://orcid.org/0000-0002-1457-991XFrozen shoulder is a prevalent condition seen in primary care in the UK, 2%–10% of the general population and up to 20% of the diabetic population (Hanchard et al., 2020; Rae et al., 2019; Walker-Bone et al., 2004). Frozen shoulder is characterised by stiffness, pain, and limitation in function. Frozen shoulder is associated with variable prognosis and management strategies (Pandey & Madi, 2021; Rangan et al., 2020; Rex et al., 2021). It can be difficult to assess, diagnose and differentiate from other shoulder pathologies (Lyne et al., 2022). This is mainly due to commonality in aetiology and subjective findings in people presenting with shoulder pain. Physical examination is an integral part of frozen shoulder diagnosis. Therefore, an early identification is important to deliver good quality of care. The delivery of care in primary care settings is changing in the UK, with remote consultations on first contact becoming more prevalent in MSK settings (Rennie et al., 2022). It is also important to note that telephone assessments remain far more in number than assessments over video-based platforms in primary care settings (Murphy et al., 2021). This presents with a new set of challenges in diagnosing frozen shoulder and may cause delay in delivery of care. There are subjective pain related complaints of frozen shoulder originally described by Codman in the 1930s and more recently by Atkin et al. (2016). These include pain constant in nature, pain on lying on the side at night and no radiating pain below the elbow. With stiffness in the shoulder being a common underlying feature. There has been a lot of research on aetiology, pathophysiology, and physical examination of frozen shoulder. However, there is a gap in the literature on exploring the relationship between key pain related subjective complaints and diagnosis of frozen shoulder. The musculoskeletal physiotherapy service in East Lothian National Health Service, Scotland, consists of a telephone consultation to triage on first contact for self-referring patients. It was noted that pain related questions were regularly asked in these remote consultations when assessing shoulder pain; however, as discussed before, their relevance has not been evaluated in the literature in depth. Therefore, a service evaluation was carried out to investigate the relationship between three questions related to pain (i.e., Is the pain constant? Is there pain lying on the side at night? Does the pain radiate below the elbow?) and a diagnosis of frozen shoulder was made following face to face assessment. Additionally, this may help to provide some insight into whether frozen shoulder and other shoulder pathologies can be differentiated based on these pain related questions.pubpu

Acquisition of procedural skills in pre-registration physiotherapy education comparing mental practice against no mental practice: The Learning of Procedures in Physiotherapy Education Trial - a development of concept study

Kavi Jagadamma - ORCID 0000-0003-2011-0744 https://orcid.org/0000-0003-2011-0744Gillian Baer - ORCID 0000-0002-1528-2851 https://orcid.org/0000-0002-1528-2851Introduction: Procedural skills are a central element in the education of physiotherapists. Procedural skills relate to the execution of a practical task. An educational intervention, which can be used to support skill acquisition of procedural skills, is mental practice (MP). Several studies have investigated the use of MP or imaging in medical education. This pilot study evaluated the application of MP on the acquisition of procedural skills in physiotherapy education.Methods: This pilot randomised controlled study recruited a convenience sample of 37 BSc physiotherapy student participants. Two different complex task procedures (transfer and vestibular rehabilitation) were trained during this study. Participants in both the transfer (task procedure 1) and the vestibular rehabilitation (task procedure 2) arm of the study were randomly assigned to either MP or no MP.Results: For the transfer task, median performance at post-acquisition testing showed a moderate effect size in favour of the group using MP (r: −0.3), but the findings were not statistically significant (P: 0.2). Similar results were found for the vestibular rehabilitation task (r: 0.29; P: 0.21). In addition, the self-reported confidence was higher in the MP group.Conclusion: Moderate effect sizes were identified in favour of MP at post-acquisition testing. In addition, the between-group difference was higher than the minimally important difference. The feasibility of the study was high based on quantitative feasibility measures such as the recruitment rate. Both these findings suggest larger well-powered studies should be considered to confirm the findings of this pilot study.https://doi.org/10.1177/23821205209273827pubpu

High-resolution cathodoluminescence hyperspectral imaging of nitride nanostructures

Hyperspectral cathodoluminescence imaging provides spectrally and spatially resolved information on luminescent materials within a single dataset. Pushing the technique toward its ultimate nanoscale spatial limit, while at the same time spectrally dispersing the collected light before detection, increases the challenge of generating low-noise images. This article describes aspects of the instrumentation, and in particular data treatment methods, which address this problem. The methods are demonstrated by applying them to the analysis of nanoscale defect features and fabricated nanostructures in III-nitride-based materials

The biomechanical optimisation (tuning) of the Ankle Foot Orthosis-Footwear Combination (AFO-FC) of children with cerebral palsy : the effects on sagittal gait characteristics, muscle and joint characteristics and quality of life

The current study aimed to investigate influences of rigid Ankle Foot Orthoses (AFOs) on gait in children with Cerebral Palsy (CP), immediate effects of tuning of AFO-FC (AFO-Footwear Combination) on gait of children with CP, short-term effects of tuning of AFO-FC on gait, muscle and joint characteristics and quality of life in children with CP, and the feasibility of conducting a larger trial. The study included 11 healthy children and 8 children with CP. Outcome measurements included sagittal plane kinematics and kinetics derived using 3D motion analysis, Gait Deviation Index (GDI), physical examination, and quality of life using the PedsQL™ questionnaire. Data from healthy children demonstrated influences of shoes on gait parameters and the role of the ankle joint in adapting to various wedges and rockers during gait. When studying children with CP, beneficial effects of rigid AFO-FC on gait parameters were evident; these were thought to relate to the appropriateness of the AFO-FC and familiarisation with the prescription. Immediate effects of tuning varied according to gait patterns previously demonstrated with non-tuned AFO-FC; benefits to knee kinematics and kinetics were largely seen in legs with extended knee gait, followed by jump knee gait, and with poorest responses in legs with crouch knee gait. Short-term effects of tuning were evident when comparing measurements taken before and after two-to-four months of wearing the tuned AFO-FC. Barefoot walking demonstrated significantly improved walking speed. Stride-length improved when comparing tuned AFO-FC at baseline with the tuned AFO-FC following the intervention period. No short-term changes were seen in PedsQL™ scores, muscle and joint characteristics, and GDI. Feasibility issues were also identified. It was concluded from this exploratory trial that tuning of AFO-FC improved gait for children with CP, although initial gait pattern affected the amount of benefit. This was evident immediately after tuning and some parameters improved further after short-term intervention. A randomised controlled trial is required; power analysis indicates the need for a larger sample of 18 in each group to detect change in GDI with a medium effect size and at a power of 0.8 and p <0.05.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Hysteresis in hybrid perovskite indoor photovoltaics

L.K.J. acknowledges funding from UKRI-FLF through grant no MR/T022094/1.Halide perovskite indoor photovoltaics (PV) are a viable solution to autonomously power the billions of sensors in the huge technology field of the Internet of Things. However, there exists a knowledge gap in the hysteresis behaviour of these photovoltaic devices under indoor lighting conditions. The present work is the first experimental study dedicated to exploring the degree of hysteresis in halide perovskite indoor photovoltaic devices by carrying out both transient J-V scan and steady state maximum power point tracking (MPPT) measurements. Dependence of hysteresis on device architecture, selection of electron transporting layers and the composition of the perovskite photoactive layers were investigated. Under indoor illumination, the p-i-n MAPbI3-based devices show consistently high power conversion efficiency (PCE) (stabilized PCE) of greater than 30% and negligible hysteresis behaviour, whereas the n-i-p MAPbI3 devices show poor performance (stabilized PCE ∼ 15%) with pronounced hysteresis effect. Our study also reveals that the n-i-p triple cation perovskite devices are more promising (stabilized PCE ∼ 25%) for indoor PV compared to n-i-p MAPbI3 due to their suppressed ion migration effects. It was observed that the divergence of the PCE values estimated from the J-V scan measurements, and the maximum power point tracking method is higher under indoor illumination compared to 1 Sun, and hence for halide perovskite-based indoor PV, the PCE from the MPPT measurements should be prioritized over the J-V scan measurements. The results from our study suggest the following approaches for maximizing the steady state PCE from halide perovskite indoor PV: (i) select perovskite active layer composition with suppressed ion migration effects (such as Cs-containing triple cation perovskites) and (ii) for the perovskite composition such as MAPbI3, where the ion migration is very active, p-i-n architecture with organic charge transport layers is beneficial over the n-i-p architecture with conventional metal oxides (such as TiO2, SnO2) as charge transport layers. This article is part of the theme issue 'Developing resilient energy systems'.Publisher PDFPeer reviewe

Interface limited hole extraction from methylammonium lead iodide films

Small solar cells based on metal halide perovskites have shown a tremendous increase in efficiency in recent years. These huge strides in device performance make it important to understand processes such as accumulation and extraction of charge carriers to better address the scalability and stability challenges which have not been solved yet. In most studies to date it is unclear whether the limiting factor of charge extraction is charge transport in the bulk of the perovskite or transfer across the interface with the charge extracting layer, owing largely to the inaccessibility of buried interfaces. Separating bulk and interfacial effects on charge extraction can help the search for new charge extracting materials, improve understanding of charge transport in active layer materials and help optimise device performance; not only in the laboratory setting but also for commercial production. Here we present a method to unambiguously distinguish between bulk and interface effects on charge extraction dynamics which is based on time-resolved photoluminescence with different excitation density profiles. We use this method to study charge extraction from solution-deposited CH3NH3PbI3 films to NiO and PEDOT:PSS layers. We find that NiO shows faster hole extraction than PEDOT:PSS from the 300 nm thick perovskite film on the time scale of 300 ps which is independent of charge carrier density in the region of 1016–1017 cm−3. The interface with NiO is found to only slightly limit charge extraction rate at charge densities exceeding 1016 cm−3 as the extraction rate is fast and does not decrease with time. This is in contrast to PEDOT:PSS where we find the charge extraction rate to be slower, decreasing with time and dependent on charge density in the region 1016–1017 cm−3 which we interpret as charge accumulation at the interface. Hence we find that charge extraction is severely limited by the interface with PEDOT:PSS. These findings are confirmed by transient absorption spectroscopy. A hole diffusion coefficient of D = (2.2 ± 0.5) cm2 s−1 was determined in the perovskite film that is independent of charge density. This indicates a band-like hole transport regime, not observed for solution processed films before. Our findings stress the importance of interface optimization in devices based on perovskite active layers as there is still room for improvement of the hole extraction rate even in the case of the superior NiO layer

The assessment of procedural skills in physiotherapy education: A measurement study using the Rasch model

Gillian Baer - ORCID 0000-0002-1528-2851 https://orcid.org/0000-0002-1528-2851Replaced AM with VoR 2020-05-26Background: Procedural skills are a key element in the training of future physiotherapists. Procedural skills relate to the acquisition of appropriate motor skills, which allow the safe application of clinical procedures to patients. In order to evaluate procedural skills in physiotherapy education validated assessment instruments are required. Recently the assessment of procedural skills in physiotherapy education (APSPT) tool was developed. The overall aim of this study was to establish the structural validity of the APSPT. In order to do this the following objectives were examined: i) the fit of the items of APSPT to the Rasch-model, ii) the fit of the overall score to the Rasch model, iii) the difficulty of each test item and iv) whether the difficulty levels of the individual test items cover the whole capacity spectrum of students in pre-registration physiotherapy education.Methods: For this observational cross-sectional measurement properties study a convenience sample of 69 undergraduate pre-registration physiotherapy students of the HES-SO Valais-Wallis was recruited. Participants were instructed to perform a task procedure on a simulated patient. The performance was evaluated with the APSPT. A conditional maximum likelihood approach was used to estimate the parameters of a partial credit model for polytomous item responses. Item fit, ordering of thresholds, targeting and goodness of fit to the Rasch model was assessed.Results: Item fit statistics showed that 25 items of the APSPT showed adequate fit to the Rasch model. Disordering of item thresholds did not occur and the targeting of the APSPT was adequate to measure the abilities of the included participants. Undimensionality and subgroup homogeneity were confirmed.Conclusion: This study presented evidence for the structural validity of the APSPT. Undimensionality of the APSPT was confirmed and therefore presents evidence that the latent dimension of procedural skills in physiotherapy education consists of several subcategories. However, the results should be interpreted with caution given the small sample size.https://doi.org/10.1186/s40945-020-00080-010pubpu

Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing

We acknowledge support from EPSRC (grant number EP/L012294/1) and the European Research Council (grant number 321305). I.D.W.S. also acknowledges a Royal Society Wolfson Research Merit Award. VS acknowledges support from the Office of Naval Research NDSEG fellowship. Research data supporting this paper is available at doi http://dx.doi.org/10.17630/eadf56f3-8c70-47da-ac6d-67f2d78b3f74Selective optimisation of light harvesting materials and interface properties has brought breakthroughs in power conversion efficiency (11-12 %) of organic photovoltaics (OPVs). However to translate this promising efficiency to economically viable applications, long term stability is a fundamental requirement. A number of degradation pathways, both extrinsic and intrinsic, reduce the long term stability of OPVs. Here, the photovoltaic properties of a highly efficient bulk heterojunction PTB7-Th:PC71BM blend were investigated as a function of thermal annealing. The changes in charge generation, separation, and transport due to thermal annealing were measured and related to changes in the microstructure and photovoltaic performance. A 30 % drop in power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 oC was identified as mainly due to morphological instability induced by strong phase separation of donor and acceptor molecules of the blend films. Based on the insight gained from these investigations, enhanced thermal stability was demonstrated by replacing the PC71BM fullerene acceptor with the non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9 % upon thermal annealing at 150 oC.PostprintPeer reviewe