Epitaxial lift-off of II-VI semiconductors from III-V substrates using a MgS release layer

Epitaxial lift-off (ELO) is a post-growth process that allows an epitaxial layer to be removed from its original substrate and transferred to a new one. ELO has previously been successfully demonstrated for III-V materials and also ZnSe based II-VI semiconductors using a MgS sacrificial layer. Following the recent successful growth of epitaxial MgS layers on GaP and InP substrates, in this paper we compare ELO of II-VI epilayers grown on GaP, GaAs, and InP substrates using MgS sacrificial layers in the range of 7-15 nm thick. Good quality lifted layers are obtained rapidly from InP and GaAs substrates. For GaP substrates, ELO is much slower and good quality lifts have only been achieved with ZnSe epilayers. Photoluminescence spectra obtained from epitaxial layers before and after ELO show changes in peak positions, which are compatible with changes of strain in the layer. The layers produced by ELO are flat and free of cracks, suggesting that this is an efficient and convenient method for the transfer of II-VI epitaxial layers to other substrates.</p

Influence of frailty in older patients undergoing emergency laparotomy: a UK-based observational study

Introduction The National Emergency Laparotomy Audit (NELA) has reported that older patients (≥65 years) form a large percentage of emergency high-risk cases with increased postoperative morbidity and mortality. With the population continuing to age rapidly, it is clear that a greater understanding of the factors affecting surgical outcomes in older patients is required. Frailty is a relatively new concept taking into account a variety of factors that increase an individual’s vulnerability to increased dependency and death. Research has suggested that high frailty scores increase postoperative complications, length of stay and mortality but the majority of these studies have been carried out on elective patients. Knowledge of how frailty affects patients in an emergency setting would aid clinicians’ and patients’ decision-making process. Methods and analysis This multicentre study will include consecutive adult patients aged 65 years and over undergoing emergency laparotomies over a 3-month period at 52 National Health Service hospitals across the UK. The primary outcome will be 90-day mortality. Secondary outcomes will include length of hospital stay, 30-day complications, change in level of independence and 30-day readmission. This study has been powered to detect a 10% change in mortality associated with frailty (n=500 patients). Ethics and dissemination This study has been approved by the National Health Service Research Ethics Committee. It has been registered centrally with HRA for English sites, NRSPCC for Scottish sites and Health and Care Research Permissions Service for sites in Wales.Dissemination will be via international and national surgical and geriatric conferences. In addition, manuscripts will be prepared following the close of the project. Trial registration number This study is also registered online at www.clinicaltrials.gov (registration number NCT02952430)

Analysis of lesion localisation at colonoscopy: outcomes from a multi-centre U.K. study

Background: Colonoscopy is currently the gold standard for detection of colorectal lesions, but may be limited in anatomically localising lesions. This audit aimed to determine the accuracy of colonoscopy lesion localisation, any subsequent changes in surgical management and any potentially influencing factors. Methods: Patients undergoing colonoscopy prior to elective curative surgery for colorectal lesion/s were included from 8 registered U.K. sites (2012–2014). Three sets of data were recorded: patient factors (age, sex, BMI, screener vs. symptomatic, previous abdominal surgery); colonoscopy factors (caecal intubation, scope guide used, colonoscopist accreditation) and imaging modality. Lesion localisation was standardised with intra-operative location taken as the gold standard. Changes to surgical management were recorded. Results: 364 cases were included; majority of lesions were colonic, solitary, malignant and in symptomatic referrals. 82% patients had their lesion/s correctly located at colonoscopy. Pre-operative CT visualised lesion/s in only 73% of cases with a reduction in screening patients (64 vs. 77%; p = 0.008). 5.2% incorrectly located cases at colonoscopy underwent altered surgical management, including conversion to open. Univariate analysis found colonoscopy accreditation, scope guide use, incomplete colonoscopy and previous abdominal surgery significantly influenced lesion localisation. On multi-variate analysis, caecal intubation and scope guide use remained significant (HR 0.35, 0.20–0.60 95% CI and 0.47; 0.25–0.88, respectively). Conclusion: Lesion localisation at colonoscopy is incorrect in 18% of cases leading to potentially significant surgical management alterations. As part of accreditation, colonoscopists need lesion localisation training and awareness of when inaccuracies can occur

Co-designing transformation research:lessons learned from research on deliberate practices for transformation

Co-production of new knowledge can enhance open and integrative research processes across the social and natural sciences and across research/science, practice and policy interrelationships. Thus, co-production is important in the conduct of research about and for transformations to sustainability. While co-design is an integral part of co-production, it often receives limited attention in the conduct of co-produced research. This paper reports on lessons learned from an early stage of the co-design process to develop research on deliberate practices for transformative change. Key lessons learned are the need to: (1) ensure co-design processes are themselves carefully designed; (2) encourage emergence of new ways of thinking about problem formulation through co-design; (3) carefully balance risks for the participants involved while also enhancing opportunities for intellectual risk taking; (4) facilitate personal transformations in co-design as a way to stimulate and encourage further creativity; and (5) for funders to carefully and constructively align criteria or incentives through which a project or future proposal will be judged to the goals of the co-design, including for instrumental outcomes and objectives for creativity and imagination. Given that co-design necessarily involves a reflective practice to iteratively guide emergence of new thinking about the practices of change, co-design can itself be considered an important deliberate practice for transforming the conduct of research and the contribution of that research to social transformations

Prognostic value of lymph node ratio and extramural vascular invasion on survival for patients undergoing curative colon cancer resection

There was no study funding. We are grateful to Tony Rafferty (Tailored Information for the People of Scotland, TIPs) for providing survival data.Peer reviewedPublisher PD

Transformation in a changing climate: a research agenda

The concept of transformation in relation to climate and other global change is increasingly receiving attention. The concept provides important opportunities to help examine how rapid and fundamental change to address contemporary global challenges can be facilitated. This paper contributes to discussions about transformation by providing a social science, arts and humanities perspective to open up discussion and set out a research agenda about what it means to transform and the dimensions, limitations and possibilities for transformation. Key focal areas include: (1) change theories, (2) knowing whether transformation has occurred or is occurring; (3) knowledge production and use; (4), governance; (5) how dimensions of social justice inform transformation; (6) the limits of human nature; (7) the role of the utopian impulse; (8) working with the present to create new futures; and (9) human consciousness. In addition to presenting a set of research questions around these themes the paper highlights that much deeper engagement with complex social processes is required; that there are vast opportunities for social science, humanities and the arts to engage more directly with the climate challenge; that there is a need for a massive upscaling of efforts to understand and shape desired forms of change; and that, in addition to helping answer important questions about how to facilitate change, a key role of the social sciences, humanities and the arts in addressing climate change is to critique current societal patterns and to open up new thinking. Through such critique and by being more explicit about what is meant by transformation, greater opportunities will be provided for opening up a dialogue about change, possible futures and about what it means to re-shape the way in which people live

II/VI metastable sulphides : fundamental studies of MBE growth, characterization and nanostructure formation

This thesis presents a fundamental study of II-VI metastable sulfides. Details of the growth by Molecular Beam Epitaxy (MBE) and characterization of CrS,ZnS,MgS, and ZnMgSSe structures on GaP and GaAs substrates are presented. Multilayer structures of ZnS/CrS and ZnMgS/CrS were grown on GaP substrates and characterized using X-ray interference. Asymmetric X-ray spectra indicated the presence of mosaic structure in the layers. A discussion on solutions to the disordered surface is presented. Superlattice structures were designed to contain 100Å of CrS. These samples were sent to the Polish academy of science for further analysis of magnetic properties. The surface morphology of zinc blende MgS layers grown on ZnSe buffer layers has been investigated by AFM. Nanowire formation is studied as a function of flux ratio and MgS layer thickness. Typical wire dimensions were found to be 0.6μm (length), 900Å (width), and 20Å (height). The method of wire formation is consistent with an anisotropic relaxation of the MgS layer by mismatch dislocations leading to a surface instability by the Asaro-Tiller-Grinfield mechanism. RHEED patterns from zincblende MgS (100) surfaces have been observed during growth, annealing and both during and after irradiation of the surface with an Mg flux. The results are compatible with the c(2x2) surface being formed from a ZnMgS alloy which converts to a pure MgS 4x1 reconstruction on Mg irradiation. Samples containing ZnMgSSe alloy were grown and analyzed by X-ray Interference. The alloy composition was found to be Zn0.20Mg0.80S0.64Se0.36. Samples with this composition are shown to be single phase using transmission electron microscopy. Structures with Zn0.20Mg0.80S0.64Se0.36 barriers were grown with ZnSe quantum wells and CdSe quantum dots, and showed good quantum confinement. The incorporation of Zn0.20Mg0.80S0.64Se0.36 in an epitaxial lift off technology has also been demonstrated

The prevalence of hyperglycaemia and its relationship with mortality, readmissions and length of stay in an older acute surgical population : a multicentre study

Funding statement This research received no specific grant from any funding agency in the public, commercial or not-for-profit sector.Peer reviewedPostprin