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Among other factors, the electrochemical capacitor (EC) properties of graphene oxide (GO) are limited by conductivity issues emanating from high oxygen concentrations. Hence, innovative GO modifications, such as derivatisation and synthesising composites with conducting polymers, are required to boost the EC properties. This allows the exploitation of the low material cost associated with carbonaceous materials. Herein, the effect of temperature (70, 130 and 190 °C) on the hydrothermal treatment of a GO/urea mixture (to form nitrogen-doped reduced GO samples U70, U130 and U190 (N-RGO), respectively) was investigated in order to study the resulting physicochemical and EC properties of N-RGO in a K2SO4 electrolyte. Subsequently, the EC properties of the N-RGO obtained from the optimum temperature were investigated in composites with polyaniline (PANI). The functionality of the composites in the electrolytes, namely, K2SO4 (SO42− radius: 258 pm) versus KOH (OH− radius: 133 pm), was compared. The nitrogen at% in GO and N-RGO (U190) was 0.39 and 6.74%, respectively, with corresponding conductivities of 4.61 × 10−7 and 4.17 × 10−1 S cm−1. Compared with GO, U130 achieved the highest increase in specific capacitance (Cs) of 200 times at 10 mV s−1. The 5 wt% PANI composite displayed the highest enhancement of Cs of 14 032% at 50 mV s−1 and 4749% at 5 mV s−1 relative to N-RGO and PANI in K2SO4, respectively. The highest Cs values for NRGO-PANI composites in KOH were more than double those of K2SO4. This work demonstrates that the hydrothermal treatment temperature tailors the physicochemical properties of the doped GO and, together with the anion size of the electrolyte and PANI wt%, synergistically tunes the EC properties of the ultimate PANI-N-RGO composite. [ABSTRACT FROM AUTHOR]

Objective: To identify the factors enabling and limiting family medicine (FM) programmes in Sub-Saharan Africa (SSA). Design: A narrative review was conducted by searching a variety of databases. Papers focusing on the training, deployment, or contribution to healthcare systems of doctors with postgraduate training in FM in SSA, published in peer-reviewed journals from 2015 onwards and in English language were included. Included papers underwent qualitative analysis. Results: Seventy-one papers were included in the review. 38% focussed on South Africa, while papers focussing on FM in a further 15 countries in SSA were identified. Key factors enabling FM programmes are support from key stakeholders, recognition of family practitioners (FP) as specialists, international collaboration, and dedicated FPs. Key factors limiting FM programmes are a lack of sufficient and well-trained faculty, inappropriate training settings, higher rates of trainee attrition, lack of FM in undergraduate curriculums, lack of career pathways, inappropriate deployment, and a lack of a critical mass. Conclusions: Support from national stakeholders, the recognition of FPs as specialists, and sustainable international collaboration promote FM programmes. The absence of a defined role within the healthcare system, low numbers of FM faculty, a poor presence in undergraduate curriculum, high attrition rate of trainees and the lack of a critical mass limit FM programmes. The standardisation of the role of FM and the implementation of undergraduate and postgraduate FM programmes with national and international collaboration could enable FM to reach a critical mass and realise its full potential in strengthening primary healthcare in SSA. [ABSTRACT FROM AUTHOR]

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]

In practice, the capacitance from the electrochemical double layer formation on porous carbon‐based electrodes is still below preferred values, limiting their use in electrochemical capacitors. The current drive is to innovate ways that generate additional capacitance in the electrochemical double layer capacitive nature of carbon nanomaterials towards both a high specific energy density (Es) and power density (Ps). Herein we report the use of metal‐organic chemical vapor deposition (MOCVD) to coat multiwalled carbon nanotubes (MWCNTs) with anatase titanium dioxide (TiO2) to induce pseudocapacitive charge storage characteristics on a carbon‐based electrode. The study shows that MWCNTs were coated in bundles, and targeted TiO2 loadings were successfully attained, though the TiO2 agglomerates also increased with TiO2 wt.%. The 10 wt.% TiO2 TiO2‐MWCNT material displayed the best capacitive behavior with associated specific discharge capacitance (Cd), Es, and Ps values of 907 F kg−1, 55.56 Wh kg−1, and 2.78 W kg−1 at 0.1 A g−1, respectively, due to the synergistic effect of the two components of the composite. Additionally, the integral capacitance (Cs) of the 20 wt.% TiO2 material was enhanced more than 5000‐fold relative to that of the 5 wt.% TiO2 TiO2‐MWCNT composite at higher scan speeds of 100 and 200 mV s−1. Electrochemical measurements further demonstrated the possible positive tuning of capacitive characteristics (charge/discharge rates, Cd and Cs) with TiO2 wt.% control. The MOCVD synthesis method imparted the TiO2‐MWCNT composites with suitable traits that showed high potential in improving physicochemical processes favorable in electrical energy storage. [ABSTRACT FROM AUTHOR]

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]

Background: Parkinson's disease (PD) is a multi-system disorder that can impact on driving ability. Little is known about how these changes in driving ability affect people with PD, making it difficult for clinicians and carers to offer appropriate support. Objective: To assess patient views concerning the effect of PD on their driving ability, the impact of these changes and how they manage them. Method: An online survey was created by a team of clinicians, people with PD, their carers, and representatives from Parkinson's UK. People with PD throughout the United Kingdom were invited to participate through Parkinson's UK's website, newsletter and Parkinson's Excellence Network email list. Results: 805 people with PD took part in the survey. We found that the loss of a driving licence had an adverse impact on employment, socialisation, travel costs and spontaneous lifestyle choices. Multiple changes in driving ability related to PD were described, including that impulse control disorders can have an adverse impact on driving. Changes in driving ability caused people to change their driving practices including taking shorter journeys and being less likely to drive at night. Participants advised managing changes in driving ability through planning, vehicle adaptions, maintaining skills and self-assessment. Conclusion: This study demonstrates the impact that changes in driving ability can have on the lifestyle of people with PD and reveals the strategies that individuals adopt to manage these changes. [ABSTRACT FROM AUTHOR]

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]

Colloidal metal chalcogenide quantum dots (QDs) have excellent quantum efficiency in light–matter interactions and good device stability. However, QDs have been brought to the forefront as viable building blocks in bottom‐up assembling semiconductor devices, the development of QD solar cell (QDSC) is still confronting considerable challenges compared to other QD technologies due to their low performance under natural sunlight, as a consequence of untapped potential from their quantized density‐of‐state and inorganic natures. This report is designed to address this long‐standing challenge by accessing the feasibility of using QDSC for indoor and concentration PV (CPV) applications. This work finds that above bandgap photon energy irradiation of QD solids can generate high densities of excitons via multi‐photon absorption (MPA), and these excitons are not limited to diffuse by Auger recombination up to 1.5 × 1019 cm−3 densities. Based on these findings, a 19.5% (2000 lux indoor light) and an 11.6% efficiency (1.5 Suns) have been facilely realized from ordinary QDSCs (9.55% under 1 Sun). To further illustrate the potential of the MPA in QDSCs, 21.29% efficiency polymer lens CPVs (4.08 Suns) and viable sensor networks powered by indoor QDSCs matrix have been demonstrated. [ABSTRACT FROM AUTHOR]

Soil water repellency, that is, the reduced ability of soils to absorb water, is thought to be caused by organic coatings with predominantly non‐polar properties on soil particle surfaces. Given the important role of particle surface polarity in determining soil water repellency, we explored the use of fluorescent probes as a method for the direct in‐situ determination of the distribution and polarity of organics on bulk soil surfaces, and of their molecular mobility. We used nile red and pyrene, which have both been used successfully as environmental probes in previous studies, but have not been applied before to bulk soils. The probes were either (a) co‐deposited with other organics known to induce water‐repellent behaviour with acid‐washed sand to produce 'model soils' or (b) adsorbed directly onto sandy soils that were naturally water repellent to different degrees, and studied using fluorescence microscopy and steady‐state and time‐resolved fluorescence. Reliable measurements could be made using pyrene as an in‐situ probe on both model and natural soils, and a viscosity/mobility probe on model soils, whereas nile red was found not to be a useful probe. On model soils, made using hexadecane (HEX), octadecane (OCT) or stearic acid (SA) on acid‐washed sand, pyrene excimer formation kinetics showed a decrease in environment mobility as the organic layer changes from a liquid through to a hard wax. Spectra from pyrene adsorbed to natural soils indicated varying environmental polarity and heterogeneity within the soil samples studied. Highlights: Exploration of in‐situ fluorescent probes to study polarity and viscosity of organics on soils.Fluorescent probes have never been used in situ on bulk soils before.Pyrene probe shows variation in mobility, polarity and heterogeneity of organics on soils.Pyrene is a useful in‐situ fluorescent probe of polarity and mobility of organics on soils. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have attracted a great deal of attention thanks to their high efficiency, ease of manufacturing, and potential low cost. However, the stability of these devices is considered their main drawback and needs to be addressed. Mesoporous carbon perovskite solar cells (m‐CPSC), consisting of three mesoporous layers (TiO2/ZrO2/C) infiltrated with CH3NH3PbI3 (MAPI) perovskite, have presented excellent lifetimes of more than 10 000 h when the additive NH2(CH2)4CO2HI (5‐ aminovaleric acid iodide; 5‐AVAI) is used to modify the perovskite structure. Yet, the role of 5‐AVAI in enhancing the stability has yet to be determined. Here, superoxide‐mediated degradation of MAPI m‐CPSC with and without the 5‐AVAI additive is studied using the fluorescence probe dihydroethidium for superoxide detection. In situ X‐ray diffractometry shows that aminovaleric acid methylammonium lead iodide (AVA‐MAPI) perovskite infiltrated in mesoporous layers presents higher stability in an ambient environment under illumination, evidenced by a slower decrease of the MAPI/PbI2 peak ratio. Superoxide yield measurements demonstrate that AVA‐MAPI generates more superoxide than regular MAPI when deposited on glass but generates significantly less when infiltrated in mesoporous layers. It is believed that superoxide formation in m‐CPSC is dependent on a combination of competitive factors including oxygen diffusion, sample morphology, grain size, and defect concentration. [ABSTRACT FROM AUTHOR]

Background: Cortical hand strokes affect the 'hand knob' of the motor cortex, resulting in isolated distal upper limb or hand weakness. They are rare and can be easily misdiagnosed for peripheral lesions.Case Reports: Case 1: A 59-year-old man presented to the Emergency Department (ED) after noticing left hand weakness while driving. There was no sensory deficit noted. A full neurological examination suggested an upper motor neurone rather than a peripheral nerve lesion. This was confirmed by a magnetic resonance imaging scan of his brain. Case 2: An 88-year-old man presented to the ED after developing sudden-onset left hand weakness while completing a newspaper puzzle. Power returned gradually over approximately 4 h, with no sensory symptoms being noted. A transient ischemic attack leading to cortical hand was diagnosed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Cortical hand strokes are a rare, but important, differential for wrist drop. They are often first strokes and embolic in nature. Therefore, correct diagnosis is vital to enable initiation of secondary prevention. [ABSTRACT FROM AUTHOR]

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]

Abstract Photovoltaics (PV) are increasingly important for electrification in rural Sub-Saharan Africa, but what is the best battery technology to use? To explore this question, a small-scale domestic PV system for South Africa (20-year lifetime) to deliver 1.42 kWh electricity from batteries overnight with 10-h discharge was costed with various Li-ion, Pb-acid and Aquion aqueous hybrid ion batteries (AHIBs). Environmental impact; compatibility with circular economy; potential for cost-reduction through lifetime extension; and valorisation of batteries at end-of-life is discussed. Batteries are 81–93% of system costs, and battery production required over the system lifetime would emit 743, 674 and 6060 kg CO2-eq (Pb-acid, Li-ion and AHIBs respectively). Hazardous materials in Li-ion and Pb-acid batteries pose risks at end-of-life. Li-ion and AHIBs face potential resource supply constraints due to use of Co, Li and graphite. Closed-loop recycling and refurbishment of Pb-acid batteries is well established in South Africa. Currently, no African facilities for Li-ion or AHIB recycling exist, with little opportunity to retain material value from these batteries within the region. Despite lower efficiencies and shorter lifetimes, Pb-acid batteries, which are readily available from domestic manufacturing at low cost, are the current best choice for sustainable small-scale domestic PV systems in South Africa. [ABSTRACT FROM AUTHOR]

We report a solvent-free approach to synthesizing organolead perovskites by using solid state reactions to coat perovskite crystals onto Al2O3 or TiO2 nanoparticles followed by addition of terpineol affording perovskite inks. We have bar cast these inks to produce photoactive perovskite thin films which are significantly more stable to humidity than solution-processed films. This new method also avoids the use of toxic DMF solvent. [ABSTRACT FROM AUTHOR]

An extremely fast annealing technique for mixed-halide perovskite solar cells is presented. Using photonic flash sintering, we have demonstrated that a spin-coated perovskite precursor may be fully annealed in as little as 1 ms. Devices annealed in 1.15 ms yielded power conversion efficiencies (PCEs) of upto 11.3% compared to 15.2% for samples annealed for 90 minutes on a hotplate. [ABSTRACT FROM AUTHOR]

A rapid annealing technique for CH3NH3PbI3 perovskite solar cells is presented. We report a co-deposited Al2O3–perovskite device annealed in under 2.5 seconds with a PCE of 10.0% compared to 10.9% for a 45 minute oven-annealed device. [ABSTRACT FROM AUTHOR]

The synthesis and full characterization of new half-squaraine dyes (Hf-SQ) containing two or three carboxylate-based linker units is reported and these dyes tested in dye-sensitized solar cell (DSC) devices. The data show improved device efficiency for a Hf-SQ dye with two linkers (η = 5.5%) compared to the highest efficiency Hf-SQ previously reported which had only a single linker (η = 5.0%); this is mainly due to improved Voc. To understand the effects of using multiple dye linker groups, device I–V data have been correlated with single crystal X-ray structural analysis and dye electrical properties (both in solution and adsorbed to TiO2) using UV-visible and ATR-IR spectroscopy along with cyclic voltammetry, and also theoretical studies using density functional theory (DFT) calculations. These data show that positioning the linkers near the dye LUMO and so that this enables complete linker chemisorption are key factors for device performance. [ABSTRACT FROM AUTHOR]