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Miniaturized photonic sources based on semiconducting two-dimensional (2D) materials offer new technological opportunities beyond the modern III-V platforms. For example, the quantum-confined 2D electronic structure aligns the exciton transition dipole moment parallel to the surface plane, thereby outcoupling more light to air which gives rise to high-efficiency quantum optics and electroluminescent devices. It requires scalable materials and processes to create the decoupled multi-quantum-well superlattices, in which individual 2D material layers are isolated by atomically thin quantum barriers. Here, we report decoupled multi-quantum-well superlattices comprised of the colloidal quantum wells of lead halide perovskites, with unprecedentedly ultrathin quantum barriers that screen interlayer interactions within the range of 6.5 Å. Crystallographic and 2D k-space spectroscopic analysis reveals that the transition dipole moment orientation of bright excitons in the superlattices is predominantly in-plane and independent of stacking layer and quantum barrier thickness, confirming interlayer decoupling., Nature Communications, 11 (1), ISSN:2041-1723

Introduction Neck of femur (NOF) fractures form a significant proportion of trauma. Especially since they do not benefit from COVID-19 social isolation policies. Surgery and hospital admissions present risks to patients during the COVID-19 pandemic. Method Retrospective analysis of all NOF fractures from 24/3/20 to 26/6/20 in Morriston Hospital. Directly compared with 2019, allowing assessment of COVID-19’s impact. Results 179 NOF fractures were admitted, 158 had an operation. Increased from 127 patients in 2019. Average time to surgery increased from 39 to 67 hours. There were operation delays for 98 patients, and non-operative treatment increased from 2 to 21 patients. Prompt orthogeriatric reviews completed in 80.4% patients in 2020, up from 72.5%. Prompt physiotherapy review increased from 66.9% to 74.6%. Mortality remained similar at 8.6% (2019) and 8.5% (2020). Average length of stay reduced; 17.4 to 11 days in 2020. Conclusions 2020 saw increased waits for operations. There was reduction in length of stay and improved promptness of orthogeriatric and physiotherapy reviews. Increased non-operative treatment in 2020, reflecting decisions about risks and benefits of surgery in the pandemic. Mortality remained stable. This department improved some aspects of care, potentially due to pressures of COVID-19 heightening awareness of patient's needs.

Colloidal nanocrystals (NCs) of lead halide perovskites have generated considerable interest in the fabrication of optoelectronic devices, such as light emitting-diodes (LEDs), because of their tunable optical bandgap, narrow spectral width, and high defect tolerance. However, the inhomogeneous halide distribution within individual NCs remains a critical challenge in order to obtain color-stable electroluminescence in mixed-halide systems. Here, we demonstrate a new post-synthetic approach, ligand-assisted solid phase synthesis (LASPS), for the preparation of electroluminescent colloidal NCs of methylammonium (MA) lead halide perovskites, at room temperature. The slow reaction kinetics preserves the morphology, size, and shape in the resulting NCs whose emission covers the entire visible spectral region with photoluminescence (PL) quantum yields (QYs) of up to >90% and colloidal stability up to several months. The LEDs fabricated using the prepared mixed-halide NCs display narrowband electroluminescence (EL) ranging from 476 to 720 nm. The optimized red LEDs exhibit an external quantum efficiency, ηext, of up to 2.65%, with the CIE 1931 color coordinates of (0.705, 0.290), nearly identical to those of the red primary in the recommendation (rec.) 2020 standard (0.708, 0.292)., We have developed a new post-synthetic approach, ligand-assisted solid phase synthesis (LASPS), to tune the optical properties of colloidal methylammonium lead halide perovskite nanocrystals with color-pure electroluminescence.

SARS-CoV-2 emerged from animals and is now easily transmitted between people. Sporadic detection of natural cases in animals alongside successful experimental infections of pets, such as cats, ferrets and dogs, raises questions about the susceptibility of animals under natural conditions of pet ownership. Here, we report a large-scale study to assess SARS-CoV-2 infection in 919 companion animals living in northern Italy, sampled at a time of frequent human infection. No animals tested PCR positive. However, 3.3% of dogs and 5.8% of cats had measurable SARS-CoV-2 neutralizing antibody titers, with dogs from COVID-19 positive households being significantly more likely to test positive than those from COVID-19 negative households. Understanding risk factors associated with this and their potential to infect other species requires urgent investigation., SARS-CoV-2 can infect cats and dogs, but the extent to which pets are infected in households remains unclear. Here, Patterson et al. test 919 companion animals in northern Italy and find that some dogs and cats from COVID-19 positive households can test positive for COVID-19 neutralizing antibodies, with dogs significantly more likely to do so if they came from COVID-19 positive households.

Magic-sized clusters (MSCs) of semiconductor are typically defined as specific molecular-scale arrangements of atoms that exhibit enhanced stability. They often grow in discrete jumps, creating a series of crystallites, without the appearance of intermediate sizes. However, despite their long history, the mechanism behind their special stability and growth remains poorly understood. It is particularly difficult to explain experiments that have shown discrete evolution of MSCs to larger sizes well beyond the "cluster" regime and into the size range of colloidal quantum dots. Here, we study the growth of MSCs, including these larger magic-sized CdSe nanocrystals, to unravel the underlying growth mechanism. We first introduce a synthetic protocol that yields a series of nine magic-sized nanocrystals of increasing size. By investigating these crystallites, we obtain important clues about the mechanism. We then develop a microscopic model that uses classical nucleation theory to determine kinetic barriers and simulate the growth. We show that magic-sized nanocrystals are consistent with a series of zinc-blende crystallites that grow layer by layer under surface-reaction-limited conditions. They have a tetrahedral shape, which is preserved when a monolayer is added to any of its four identical facets, leading to a series of discrete nanocrystals with special stability. Our analysis also identifies strong similarities with the growth of semiconductor nanoplatelets, which we then exploit to further increase the size range of our magic-sized nanocrystals. Although we focus here on CdSe, these results reveal a fundamental growth mechanism that can provide a different approach to nearly monodisperse nanocrystals.

ISSN:1071-0922 ISSN:1938-3657

Unlike interictal Positron Emission Tomography (PET), ictal PET is not regularly used in the study of refractory focal epilepsy, and its usefulness in presurgical evaluations, and prognosis value have not been established. The aim is to present six patients with epilepsy whose PET/CT brain scans showed focal hypermetabolism, and analyze their correlation with the histopathological findings and clinical results. We reviewed 146 18F-FDG PET/CT scans performed on patients with refractory focal epilepsy. Only those cases with hypermetabolic foci which were subsequently surgically resected were selected. The epidemiological and clinical data were reviewed in addition to the brain MRI, Electroencephalography (EEG), video-EEG monitoring, intraoperative Electrocorticography (ECoG), histopathology, and postsurgical outcome. The PET findings were correlated with the clinical characteristics of the seizures, the EEG, brain MRI, ECoG, and histopathology. Seven PET/CT scans carried out on six patients showed well-defined hypermetabolic foci (three temporal, four extratemporal). There was a high correlation between the clinical lateralization, EEG/ECoG findings, and hypermetabolic foci located by PET. An MRI correctly identified the resected histopathological lesion in five cases and it was negative in two. Three patients had Focal Cortical Dysplasia (FCD), one had FCD with areas of polymicrogyria, one had temporal lobe cavernoma associated with hippocampal sclerosis, and one had a focal subcortical heterotopia. Mean postsurgical follow-up was 29.1 months (range: 16-24 months) and all patients were seizure free during this period. This small series of patients who underwent surgery for intractable focal epilepsy have shown good correlation between the ictal F18-FDG PET/CT scan and the electroclinical and pathological findings. These results suggest that hypermetabolic foci showed in PET/CT provides a reliable estimation of epileptogenic zone. Focus size underestimation in one case suggest the need of doing an interictal PET before surgery.

A Leica camera on an indexing head was used to obtain photographic panoramas from three stations on a mountaineering expedition to Lahul in 1958. The field calibration of the camera presented some problems and various methods of calculating the focal length were investigated; a more convenient form of the Hotine method was derived. A map of the area at a scale of 1:50,000 was plotted from the photographs. The authors conclude that a good 35-mm. camera has some advantages over a plane table for exploration mapping.

Background Little is known about the sensations patients feel prior to or that provoke their cough. Aims To identify, from the patient9s perspective, key descriptors that relate to the sensations provoking cough in patients diagnosed with one of the following: idiopathic cough, asthma, chronic obstructive pulmonary disease (COPD), fibrotic interstitial lung disease (ILD) and cystic fibrosis. Methods One-to-one, audio recorded, semi- structured interviews were conducted with 34 participants (7 idiopathic cough: age 40–69 years, 5 female, 6 asthma: age 42–65 years, 5 female, 7 COPD: age 52–86 years, 2 female, 7 ILD: age 58–79 years, 3 female, 7 cystic fibrosis: age 20–39 years, 2 female). Words and phrases relating to 1 of 8 top level codes, derived from the interview topic guide (triggers, sensation, sputum, emotion, location, frequency, time and relief) were extracted using simple manifest content analysis. These descriptions were then organised into similar themes. Relationships between the descriptions and themes both within and between the groups were explored. Results All groups described the sensation of a “tickle” or an “irritation” that was felt most in the throat and upper chest. Cystic fibrosis and COPD participants most commonly described feeling a “need to clear” their airways. The ILD group mostly described a “dry”, “tickly” sensation. The idiopathic cough and asthma groups used a very heterogeneous set of terms regarding the sensations provoking their cough. Common across the groups is a hypersensitive response to things that may trigger their urge to cough and all groups described coughing as relieving that urge. Emotionally the sensation is associated with negative emotions, however positive feelings were also described; by some who described feeling a need to clear their airways. Conclusion The extracted list of descriptions has provided some insight into what the sensations provoking cough feel like from patient9s perspective and suggest that the sensations felt relate to the pathology of the individual9s diagnosis. The distinction between the need to clear and a sensation of a tickle or irritation could be important in understanding the mechanisms driving cough and may be important for the development of targeted interventions.