1,221 research outputs found
COVID-19 among ethnic minorities:How missing data and colour-blind policies perpetuate inequalities in the United Kingdom and the European Union
Morphology control of epitaxial monolayer transition metal dichalcogenides
Funding: AFM system (funded via an EPSRC equipment grant: EP/L017008/1) used in this work and experimental support. The Leverhulme Trust (Grant no. RL-2016-006); The Royal Society; the European Research Council (Grant No. ERC-714193-QUESTDO). K.U. acknowledges EPSRC for PhD studentship support through grant no. EP/L015110/1.To advance fundamental understanding and ultimate application of transition-metal dichalcogenide (TMD) monolayers, it is essential to develop capabilities for the synthesis of high-quality single-layer samples. Molecular beam epitaxy (MBE), a leading technique for the fabrication of the highest-quality epitaxial films of conventional semiconductors has, however, typically yielded only small grain sizes and suboptimal morphologies when applied to the van der Waals growth of monolayer TMDs. Here, we present a systematic study on the influence of adatom mobility, growth rate, and metal:chalcogen flux on the growth of NbSe2, VSe2, and TiSe2 using MBE. Through this, we identify the key drivers and influence of the adatom kinetics that control the epitaxial growth of TMDs, realizing four distinct morphologies of the as-grown compounds. We use this to determine optimized growth conditions for the fabrication of high-quality monolayers, ultimately realizing the largest grain sizes of monolayer TMDs that have been achieved to date via MBE growth.PostprintPeer reviewe
Induction of fibroblast senescence generates a non-fibrogenic myofibroblast phenotype that differentially impacts on cancer prognosis
Cancer-associated fibroblasts (CAF) remain a poorly characterized, heterogeneous cell population. Here we characterized two previously described tumor-promoting CAF sub-types, smooth muscle actin (SMA)-positive myofibroblasts and senescent fibroblasts, identifying a novel link between the two
Engineering standards for trauma and orthopaedic implants worldwide : a systematic review protocol
Introduction
Despite multiple scandals in the medical implant sector, premarket testing has been the attention of little published research. Complications related to new devices, such as the DePuy Articular Surface Replacement (ASR, DePuy Synthes, USA), have raised the issue of how designs are tested and whether engineering standards remain up to date with our understanding of implant biomechanics. Despite much work setting up national joint registries to improve implant monitoring, there have been few academic studies examining the premarket engineering standards new implants must meet. Emerging global economies mean that the markets have changed, and it is unknown to what degree engineering standards vary around the world. Governments, industry and independent regulatory bodies all produce engineering standards; therefore, the comparison of surgical implants across different manufacturers and jurisdictions is difficult. In this review, we will systematically collate and compare engineering standards for trauma and orthopaedic implants around the world. This will help inform patient, hospital and surgeon choice and provide an evidence base for future research in this area.
Methods and analysis
This protocol is based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) guidelines. We will conduct a systematic review of trauma and orthopaedic engineering standards from four main sources of information as identified in our preliminary scoping searches: governments, industry, independent regulatory bodies and engineering and medical publications. Any current standard relevant to trauma and orthopaedic implants will be included. We will use a predefined search strategy and follow the recommendations of the Cochrane handbook where applicable. We will undertake a narrative synthesis with qualitative evaluation of homogeneity between engineering standards.
Ethics and dissemination
No ethics approval is required as no primary data are being collected. The results will be made available by peer-reviewed publication and reported according to PRISMA-P guidelines
Chord distribution functions of three-dimensional random media: Approximate first-passage times of Gaussian processes
The main result of this paper is a semi-analytic approximation for the chord
distribution functions of three-dimensional models of microstructure derived
from Gaussian random fields. In the simplest case the chord functions are
equivalent to a standard first-passage time problem, i.e., the probability
density governing the time taken by a Gaussian random process to first exceed a
threshold. We obtain an approximation based on the assumption that successive
chords are independent. The result is a generalization of the independent
interval approximation recently used to determine the exponent of persistence
time decay in coarsening. The approximation is easily extended to more general
models based on the intersection and union sets of models generated from the
iso-surfaces of random fields. The chord distribution functions play an
important role in the characterization of random composite and porous
materials. Our results are compared with experimental data obtained from a
three-dimensional image of a porous Fontainebleau sandstone and a
two-dimensional image of a tungsten-silver composite alloy.Comment: 12 pages, 11 figures. Submitted to Phys. Rev.
Orbital-selective band hybridisation at the charge density wave transition in monolayer TiTe2
Funding: We gratefully acknowledge support from the Leverhulme Trust and the Royal Society. W.R. is grateful to University College London for awarding a Graduate Research Scholarship and an Overseas Research Scholarship. O.J.C. and K.U. acknowledge PhD studentship support from the UK Engineering and Physical Sciences Research Council (EPSRC, Grant Nos. EP/K503162/1 and EP/L015110/1). I.M. and E.A.-M. acknowledge studentship support from the International Max-Planck Research School for Chemistry and Physics of Quantum Materials. S.R.K. acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM, EP/S023259/1) for funding a PhD studentship.Reducing the thickness of a material to its two dimensional (2D) limit can have dramatic consequences for its collective electronic states, including magnetism, superconductivity, and charge and spin ordering. An extreme case is TiTe2, where a charge density wave (CDW) emerges in the single-layer which is absent for the bulk compound, and whose origin is still poorly understood. Here, we investigate the electronic band structure evolution across this CDW transition using temperature-dependent angle-resolved photoemission spectroscopy. Our study reveals an orbital-selective band hybridisation between the backfolded conduction and valence bands occurring at the CDW phase transition, which in turn leads to a significant electronic energy gain, underpinning the CDW transition. For the bulk compound, we show how this energy gain is almost completely suppressed due to the three-dimensionality of the electronic band structure, including via a kz-dependent band inversion which switches the orbital character of the valence states. Our study thus sheds new light on how control of the electronic dimensionality can be used to trigger the emergence of new collective states in 2D materials.Publisher PDFPeer reviewe
Synthesis and activity of a novel Autotaxin inhibitor-Icodextrin conjugate
© Copyright 2018 American Chemical Society. Autotaxin is an extracellular phospholipase D that catalyses the hydrolysis of lysophosphatidyl choline (LPC) to generate the bioactive lipid lysophosphatidic acid (LPA). Autotaxin has been implicated in many pathological processes relevant to cancer. Intraperitoneal administration of an autotaxin inhibitor may benefit patients with ovarian cancer, however low molecular mass compounds are known to be rapidly cleared from the peritoneal cavity. Icodextrin is a polymer that is already in clinical use because it is slowly eliminated from the peritoneal cavity. Herein we report conjugation of the autotaxin inhibitor HA-155 to icodextrin. The conjugate inhibits autotaxin activity (IC50 = 0.86 ± 0.13 μg mL-1) and reduces cell migration. Conjugation of the inhibitor increased its solubility, decreased its membrane permeability and improved its intraperitoneal retention in mice. These observations demonstrate the first application of icodextrin as a covalently-bonded drug delivery platform with potential use in the treatment of ovarian cancer
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