What supports and services post COVID-19 do children with disabilities and their parents need and want, now and into the future?

Introduction: Children and youth with disabilities and special healthcare needs, and their families, have been uniquely affected by the COVID-19 pandemic. However, the voices of children themselves are still not well represented in the existing literature. Methods: This qualitative descriptive study used a combination of visual methods and interviews to learn about the experiences of Canadian children with disabilities (n=18) and their parents (n=14) during the COVID pandemic and into the post-pandemic period. Data collection was carried out between January and July 2023. The aim was to identify the supports and services children and families need at present and moving forward. Results: Families' pandemic experiences were complex and nuanced. For many, the pandemic complicated and disrupted everyday activities and supports. These disruptions were largely buffered by parents. However, some families also identified unexpected benefits. Key themes pertaining to present and future needs included the need for services that are flexible; consistent; conducive to relationship-building; comprehensive; coordinated across sectors; and designed to support the needs of the whole family. Discussion: Implications for policy and practice are outlined.

Life expectancy inequalities in Wales before COVID-19: an exploration of current contributions by age and cause of death and changes between 2002 and 2018.

OBJECTIVES: The COVID-19 pandemic in Wales and the UK has highlighted significant and historic inequalities in health between social groups. To better understand the composition of these inequalities and inform planning after the pandemic, we undertook a decomposition of life expectancy inequalities between the most and least deprived quintiles for men and women by age and cause of death and explored trends between 2002 and 2018. STUDY DESIGN: Statistical decomposition of life expectancy inequalities by age and cause of death using routine population mortality datasets. METHODS: We used routine statistics from the Office for National Statistics for the period 2002-2018 on population and deaths in Wales stratified by age, gender, Welsh Index of Multiple Deprivation (WIMD) 2019 quintile and cause of death, categorised by International Classification of Disease, version 10, code into 15 categories of public health relevance. We aggregated data to 3-year rolling figures to account for low numbers of events in some groups annually. Next, we estimated life expectancy at birth by quintile, gender and period using life table methods. Lastly, we performed a decomposition analysis using the Arriaga method to identify the specific disease categories and ages at which excess deaths occur in more disadvantaged areas to highlight potential areas for action. RESULTS: Life expectancy inequalities between the most and least WIMD quintiles rose for both genders between 2002 and 2018: from 4.69 to 6.02 years for women (an increase of 1.33 years) and from 6.34 to 7.42 years for men (an increase of 1.08 years). Exploratory analysis of these trends suggested that the following were most influential for women: respiratory disease (1.50 years), cancers (1.36 years), circulatory disease (1.35 years) and digestive disease (0.51 years). For men, the gap was driven by circulatory disease (2.01 years), cancers (1.39 years), respiratory disease (1.25 years), digestive disease (0.79 years), drug- and alcohol-related conditions (0.54 years) and external causes (0.54 years). Contributions for women from respiratory disease, cancers, dementia and drug- and alcohol-related conditions appeared to be increasing, while among men, there were rising contributions from respiratory, digestive and circulatory disease. CONCLUSIONS: Life expectancy inequalities in Wales remain wide and have been increasing, particularly among women, with indications of worsening trends since 2010 following the introduction of fiscal austerity. As agencies recover from the pandemic, these findings should be considered alongside any resumption of services in Wales or future health and public policy.

3D Strain in 2D Materials: To What Extent is Monolayer Graphene Graphite?

This work addresses a fundamental question: To what extent is graphene graphite? In particular does 2D graphene have many of the same 3D mechanical properties as graphite, such as the bulk modulus and elastic constant c_{33}? We have obtained, for the first time, unambiguous Raman spectra from unsupported monolayer graphene under pressure. We have used these data to quantify the out-of-plane stiffness of monolayer graphene, which is hard to define due to its 2D nature. Our data indicate a first physically meaningful out-of-plane stiffness of monolayer graphene, and find it to be consistent with that of graphite. We also report a shift rate of the in-plane phonon frequency of unsupported monolayer graphene to be 5.4 cm^{-1} GPa^{-1}, very close to that of graphite (4.7 cm^{-1} GPa^{-1}), contrary to the previous value for supported graphene. Our results imply that monolayer graphene has similar in-plane and out-of-plane stiffnesses, and anharmonicities to graphite.

Resonant photoluminescence studies of carrier localisation in c-plane InGaN/GaN quantum well structures.

In this paper we report on changes in the form of the low temperature (12 K) photoluminescence spectra of an InGaN/GaN quantum well structure as a function of excitation photon energy. As the photon energy is progressively reduced we observe at a critical energy a change in the form of the spectra from one which is determined by the occupation of the complete distribution of hole localisation centres to one which is determined by the resonant excitation of specific localisation sites. This change is governed by an effective mobility edge whereby the photo-excited holes remain localised at their initial energy and are prevented from scattering to other localisation sites. This assignment is confirmed by the results of atomistic tight binding calculations which show that the wave function overlap of the lowest lying localised holes with other hole states is low compared with the overlap of higher lying hole states with other higher lying hole states.

A qualitative study exploring awareness and attitudes towards tuberculosis in migrant populations in a Metropolitan District Council in the North of England.

Background: The majority of tuberculosis (TB) cases in the UK occur among people born in high-burden countries (73%), and are concentrated in large urban centres. This study explores migrants' attitudes and beliefs towards TB in an English District where the incidence is higher than the UK average. Methods: Community engagement workers ran 26 focus groups using a standardized questionnaire. Purposeful sampling was used to obtain a cross-section of migrant communities. The summary reports were analysed using thematic analysis. Results: Most groups did not see TB as a current issue in their community and associated it either with the past or with their country of birth. It appeared to be rarely discussed in their communities and generally not noted as being associated with stigma. Conclusions: This study revealed a change in social attitudes to TB in migrant groups to those reported in previous literature. Stigma had considerably less effect than expected. However, the evidence revealed that these high-risk groups made the erroneous assumption that, by moving to a low incidence country, they were no longer at risk of the disease. TB services need to respond by revising the information that they provide to take into account the risk perception of these populations.

The atomic structure of polar and non-polar InGaN quantum wells and the green gap problem.

We have used high resolution transmission electron microscopy (HRTEM), aberration-corrected quantitative scanning transmission electron microscopy (Q-STEM), atom probe tomography (APT) and X-ray diffraction (XRD) to study the atomic structure of (0001) polar and (11-20) non-polar InGaN quantum wells (QWs). This paper provides an overview of the results. Polar (0001) InGaN in QWs is a random alloy, with In replacing Ga randomly. The InGaN QWs have atomic height interface steps, resulting in QW width fluctuations. The electrons are localised at the top QW interface by the built-in electric field and the well-width fluctuations, with a localisation energy of typically 20meV. The holes are localised near the bottom QW interface, by indium fluctuations in the random alloy, with a localisation energy of typically 60meV. On the other hand, the non-polar (11-20) InGaN QWs contain nanometre-scale indium-rich clusters which we suggest localise the carriers and produce longer wavelength (lower energy) emission than from random alloy non-polar InGaN QWs of the same average composition. The reason for the indium-rich clusters in non-polar (11-20) InGaN QWs is not yet clear, but may be connected to the lower QW growth temperature for the (11-20) InGaN QWs compared to the (0001) polar InGaN QWs.

A phase II study of tivozanib in patients with metastatic and nonresectable soft-tissue sarcomas.

Background: Soft tissue sarcomas (STSs) overexpress vascular endothelial growth factors (VEGF) and VEGF-receptors (VEGFR) activation have been associated with tumor aggressiveness. Tivozanib is a potent small molecule tyrosine kinase inhibitor against VEGFR1-3, with activity against PDGFRα/ß and cKIT. The primary endpoint of this study was progression free survival (PFS) rate at 16 weeks. Secondary end points were overall survival (OS), response rate, safety and correlative studies. Patients and methods: A Simon two-stage phase II trial was performed using tivozanib given orally at 1.5 mg daily, 3 week on 1 week off on a 28 day cycle until disease progression or intolerable toxicity. Results: Fifty-eight patients were enrolled and treated with tivozanib. Leiomyosarcoma was the most common STS histological type in our cohort (47%) and 27 patients (46%) had received at least 3 lines of therapy prior to study entry. Up to 24 patients (41%) had prior VEGF targeted therapies. Partial response and stable disease were observed in 2 (3.6%) and 30 (54.5%) patients. The 16 week PFS rate was 36.4% [95% confidence interval (CI) 23.7-49.1] and a median PFS of 3.5 months (95% CI 1.8-3). Median OS observed was 12.2 months (95% CI 8.1-16.8). The most frequent all grade toxicities were fatigue (48.3%), hypertension (43.1%), nausea (31%) and diarrhea (27.6%). The most common grade three toxicity was hypertension (22.4%). Correlative studies demonstrate no correlation between the expression of VEGFR 1, 2 or 3, PDGFRα/ß or FGF, and activity of tivozanib. Conclusion: Tivozanib was well tolerated and showed antitumor activity with a promising median PFS and PFS rate at 4 months in a heavily pretreated population of metastatic STSs. Our results support further studies to assess the clinical efficacy of tivozanib in STS. Clinical Trial Number: NCT01782313.

High-quality III-nitride films on conductive, transparent (2Ì 01)-oriented ß-Ga2O3 using a GaN buffer layer.

We demonstrate the high structural and optical properties of InxGa1-xN epilayers (0 ≤ x ≤ 23) grown on conductive and transparent (01)-oriented ß-Ga2O3 substrates using a low-temperature GaN buffer layer rather than AlN buffer layer, which enhances the quality and stability of the crystals compared to those grown on (100)-oriented ß-Ga2O3. Raman maps show that the 2″ wafer is relaxed and uniform. Transmission electron microscopy (TEM) reveals that the dislocation density reduces considerably (~4.8 × 10(7) cm(-2)) at the grain centers. High-resolution TEM analysis demonstrates that most dislocations emerge at an angle with respect to the c-axis, whereas dislocations of the opposite phase form a loop and annihilate each other. The dislocation behavior is due to irregular (01) ß-Ga2O3 surface at the interface and distorted buffer layer, followed by relaxed GaN epilayer. Photoluminescence results confirm high optical quality and time-resolved spectroscopy shows that the recombination is governed by bound excitons. We find that a low root-mean-square average (≤1.5 nm) of InxGa1-xN epilayers can be achieved with high optical quality of InxGa1-xN epilayers. We reveal that (01)-oriented ß-Ga2O3 substrate has a strong potential for use in large-scale high-quality vertical light emitting device design.

Heterogeneous integration of gallium nitride light-emitting diodes on diamond and silica by transfer printing.

We report the transfer printing of blue-emitting micron-scale light-emitting diodes (micro-LEDs) onto fused silica and diamond substrates without the use of intermediary adhesion layers. A consistent Van der Waals bond was achieved via liquid capillary action, despite curvature of the LED membranes following release from their native silicon growth substrates. The excellence of diamond as a heat-spreader allowed the printed membrane LEDs to achieve optical power output density of 10 W/cm(2) when operated at a current density of 254 A/cm(2). This high-current-density operation enabled optical data transmission from the LEDs at 400 Mbit/s.

Direct observation of depth-dependent atomic displacements associated with dislocations in gallium nitride.

We demonstrate that the aberration-corrected scanning transmission electron microscope has a sufficiently small depth of field to observe depth-dependent atomic displacements in a crystal. The depth-dependent displacements associated with the Eshelby twist of dislocations in GaN normal to the foil with a screw component of the Burgers vector are directly imaged. We show that these displacements are observed as a rotation of the lattice between images taken in a focal series. From the sense of the rotation, the sign of the screw component can be determined.

Prospects of III-nitride optoelectronics grown on Si.

The use of III-nitride-based light-emitting diodes (LEDs) is now widespread in applications such as indicator lamps, display panels, backlighting for liquid-crystal display TVs and computer screens, traffic lights, etc. To meet the huge market demand and lower the manufacturing cost, the LED industry is moving fast from 2 inch to 4 inch and recently to 6 inch wafer sizes. Although Al2O3 (sapphire) and SiC remain the dominant substrate materials for the epitaxy of nitride LEDs, the use of large Si substrates attracts great interest because Si wafers are readily available in large diameters at low cost. In addition, such wafers are compatible with existing processing lines for 6 inch and larger wafers commonly used in the electronics industry. During the last decade, much exciting progress has been achieved in improving the performance of GaN-on-Si devices. In this contribution, the status and prospects of III-nitride optoelectronics grown on Si substrates are reviewed. The issues involved in the growth of GaN-based LED structures on Si and possible solutions are outlined, together with a brief introduction to some novel in situ and ex situ monitoring/characterization tools, which are especially useful for the growth of GaN-on-Si structures.

Mg doping affects dislocation core structures in GaN.

Aberration-corrected scanning transmission electron microscopy was used to investigate the core structures of threading dislocations in undoped GaN films with both high and low dislocation densities, and in a comparable high dislocation density Mg-doped GaN film. All a-type dislocations in all samples have a 5/7-atom core structure. In contrast, most (a+c)-type dislocations in undoped GaN dissociate due to local strain variations from nearby dislocations. In contrast, Mg doping prevents (a+c)-type dislocation dissociation. Our data indicate that Mg affects dislocation cores in GaN significantly.

Development and testing of models of tuberculosis contact tracing in rural southern Africa.

SETTING: A regional hospital in rural Swaziland. OBJECTIVES: To evaluate a hospital-based contact screening programme and test approaches to improve its effectiveness. DESIGN: An evaluation and quality improvement study of tuberculosis (TB) contact tracing services. RESULTS: Hospital-based TB contact tracing led to screening of 157 (24%) of 658 contacts; of these, 4 (2.5%) were diagnosed with TB. Of 68 contacts eligible for human immunodeficiency virus (HIV) testing and counselling, 45 (66%) were tested and 7/45 (16%) were identified as HIV-positive. Twelve (50%) of 24 screened contacts aged <5 years were provided isoniazid prophylaxis. Three enhanced models of TB contact tracing were piloted to screen contacts in the community. Although some enhanced models screened large numbers of contacts, no contacts were diagnosed with TB. CONCLUSION: Contact tracing of household members conducted in TB clinics within hospital settings is effective in high-burden, low-income settings, and can be provided using current resources. Enhanced household contact tracing models that followed up contacts in the community were not found to be effective. Additional resources would be required to provide household TB contact tracing in the community.

The significance of Bragg's law in electron diffraction and microscopy, and Bragg's second law.

Bragg's second law, which deserves to be more widely known, is recounted. The significance of Bragg's law in electron diffraction and microscopy is then discussed, with particular emphasis on differences between X-ray and electron diffraction. As an example of such differences, the critical voltage effect in electron diffraction is described. It is then shown that the lattice imaging of crystals in high-resolution electron microscopy directly reveals the Bragg planes used for the imaging process, exactly as visualized by Bragg in his real-space law. Finally, it is shown how in 2012, for the first time, on the centennial anniversary of Bragg's law, single atoms have been identified in an electron microscope using X-rays emitted from the specimen. Hence atomic resolution X-ray maps of a crystal in real space can be formed which give the positions and identities of the different atoms in the crystal, or of a single impurity atom in the crystal.

Atom probe tomography and transmission electron microscopy of a Mg-doped AlGaN/GaN superlattice.

The electronic characteristics of semiconductor-based devices are greatly affected by the local dopant atom distribution. In Mg-doped GaN, the clustering of dopants at structural defects has been widely reported, and can significantly affect p-type conductivity. We have studied a Mg-doped AlGaN/GaN superlattice using transmission electron microscopy (TEM) and atom probe tomography (APT). Pyramidal inversion domains were observed in the TEM and the compositional variations of the dopant atoms associated with those defects have been studied using APT. Rarely has APT been used to assess the compositional variations present due to structural defects in semiconductors. Here, TEM and APT are used in a complementary fashion, and the strengths and weaknesses of the two techniques are compared.

Imaging dislocations in gallium nitride across broad areas using atomic force microscopy.

We have employed an atomic force microscope with a high sampling rate to image GaN samples grown using an epitaxial layer overgrowth technique and treated with silane and ammonia to enlarge the surface pits associated with threading dislocations (TDs). This allows TDs to be identified in high pixel density images tens of microns in size providing detailed information about the spatial distribution of the TDs. An automated software tool has been developed, which identifies the coordinates of the TDs in the image. Additionally, we have imaged the same sample using Kelvin probe force microscopy, again at high pixel density, providing data about the local changes in surface potential associated with hundreds of dislocations.

Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN.

For non-centrosymmetric crystals, the refinement of charge-density maps requires highly accurate measurements of structure-factor phase, which can now be obtained using the extinction-free convergent-beam electron microdiffraction method. We report here accurate low-order structure-factor phases and amplitudes for gallium nitride (GaN) in the wurtzite structure. The measurement accuracy is up to 0.1% for amplitude and 0.2 degrees for phases. By combining these with high-order structure factors from electronic structure calculation, charge-density maps were obtained. Fine bonding features suggest that the Ga-N bonds are polar and covalent, with charge transfer from Ga to N; however, the polarity effect is extremely small.

Lattice distortions in GaN on sapphire using the CBED-HOLZ technique.

The convergent beam electron diffraction (CBED) methodology was developed to investigate the lattice distortions in wurtzite gallium nitride (GaN) from a single zone-axis pattern. The methodology enabled quantitative measurements of lattice distortions (alpha, beta, gamma and c) in transmission electron microscope (TEM) specimens of a GaN film grown on (0,0,0,1) sapphire by metal-organic vapour-phase epitaxy. The CBED patterns were obtained at different distances from the GaN/sapphire interface. The results show that GaN is triclinic above the interface with an increased lattice parameter c. At 0.85 microm from the interface, alpha=90 degrees , beta=8905 degrees and gamma=11966 degrees . The GaN lattice relaxes steadily back to hexagonal further away from the sapphire substrate. The GaN distortions are mainly confined to the initial stages of growth involving the growth and the coalescence of 3D GaN islands.

HANSIS software tool for the automated analysis of HOLZ lines.

A software tool, named as HANSIS (HOLZ analysis), has been developed for the automated analysis of higher-order Laue zone (HOLZ) lines in convergent beam electron diffraction (CBED) patterns. With this tool, the angles and distances between the HOLZ intersections can be measured and the data can be presented graphically with a user-friendly interface. It is capable of simultaneous analysis of several HOLZ patterns and thus provides a tool for systematic studies of CBED patterns.