159370 research outputs found
Sort by
Fabrication and characterization of boron-terminated tetravacancies in monolayer hBN using STEM, EELS and electron ptychography
Get PDFTetravacancies in monolayer hexagonal boron nitride (hBN) with consistent edge termination (boron or nitrogen) form triangular nanopores with electrostatic potentials that can be leveraged for applications such as selective ion transport and neuromorphic computing. In order to quantitatively predict the properties of these structures, an atomic-level understanding of their local electronic and chemical environments is required. Moreover, robust methods for their precision manufacture are needed. Here we use electron irradiation in a scanning transmission electron microscope (STEM) at a high dose rate to drive the formation of boron-terminated tetravacancies in monolayer hBN. Characterization of the defects is achieved using aberration-corrected STEM, monochromated electron energy-loss spectroscopy (EELS), and electron ptychography. Z-contrast in STEM and chemical fingerprinting by core-loss EELS enable identification of the edge terminations, while electron ptychography gives insight into structural relaxation of the tetravacancies and provides evidence of enhanced electron density around the defect perimeters indicative of bonding effects
Innovative P(3HB)/carbon-based material composites for bone tissue regeneration: Biocompatibility, thermo-mechanical, and structural insights
Get PDFBone tissue engineering (BTE) aims to address the challenge of repairing critical size bone defects, but effective substitutes with suitable mechanical properties and bioactivity are still needed. Poly(3-hydroxybutyrate), P(3HB)is a sustainable polymer with promising potential but suffers from poor mechanical properties and thermal instability. In this study, P(3HB) was reinforced with various carbon-based materials (CBMs) to evaluate thermomechanical and structural properties as well as biological responses, in composites before and after aging. CBMs with P(3HB) interactions and their spatial distribution were examined using advanced imaging, including Atomic Force Microscopy (AFM), Secondary Electron Hyperspectral Imaging (SEHI), and Short-Wave Infrared (SWIR) analysis. Biological responses were assessed using various biocompatibility assays; cytotoxicity and osteogenicity with primary human osteoblasts (ECACC, 406-05a) and MG63 cells. Aged P(3HB)/inkjet composites showed a 140 % increase in Young's modulus (1.2 GPa), matching trabecular bone stiffness, with a 3 % lower processing temperature than neat P(3HB), enhancing suitability for 3D printing. SEHI revealed elevated OH (4.8 eV) and CO (5.7 eV) functional groups, resulting in increased surface hydrophilicity and promoted cellular responses. P(3HB)/inkjet demonstrated the highest cell attachment (267.5 ± 43.3 cells) and ALP activity (6.3 ± 0.7 nmol PNP/min), outperforming composites with Starbon (150.1 ± 38.3 cells, 6.1 ± 0.8 ALP) and activated carbon (103.4 ± 24.5 cells, 5.7 ± 0.5 ALP). All aged composites showed improved performance over their fresh counterparts. In contrast, TCP and neat P(3HB) exhibited the lowest levels of mineralization. 3D printing offers further potential for enhancing P(3HB)/inkjet composites through precise and bespoke scaffold design and clinical feasibility
Ultrasonic resonance approach to measure rolling element bearing raceway films in-situ: A practical approach
Get PDFThe lubricant film adhering to a bearing raceway is the primary contributor to developing an adequate inlet meniscus to avoid starvation and thus premature wear. This paper shows that lubricant films adhering to the raceways of rolling element bearings are measurable via an in-situ ultrasonic resonance technique, that is applicable to fully metallic bearings. This work first validates the measurement of free-surface oil films on bearing steel using the ultrasonic resonance method before applying to a fully metallic, cylindrical roller bearing. Practical considerations are discussed to optimise the measurement range and accuracy, and limitations are highlighted. Quantifying a dynamic raceway film into single thickness measurements is discussed, and two oils with a magnitude difference in viscosity are compared
Treatment of enteric fever (typhoid and paratyphoid fever) with cephalosporins: a Cochrane review
No full textMaritime security technologies and coastal neo-fortification
Get PDFData technologies promise new ways of tackling maritime security challenges - from trafficking and smuggling, to environmental crime and terrorism. This is particularly the case at coastlines, where global security threats manifest as local maritime issues, and where general maritime traffic conceals small vessel landings, drug drops and clandestine movements. Coastlines are increasingly sites of technological neo-fortification, the prime aim of which is the detection and tracking of seaborne movement. This article draws on qualitative fieldwork with volunteers monitoring the British coast and research on global maritime security technologies. It gains critical traction on new technologies by placing them within a history of littoral fortification, which I show has always been concerned with discerning movement at sea. I make two contributions. First, I show that the machine learning technologies govern maritime movement through movement, weaponising the ocean’s materiality in the pursuit of so-called dark targets. Second, I argue that the techno neo-fortification of coastlines is underpinned by algorithmic spatialities and differentiations that seek to render wider ocean movement controllable. Bordering and security practice - from launching life-saving search and rescue missions, to targeting “small boats”, countering illegal fishing and disrupting smuggling - is re-ordered via these spatialities and differentiations. Contemporary maritime security technologies do not enhance existing practice: rather, they are reorganising sea borders, reconfiguring the relationship between territorial and global waters, and altering how life is governed at sea
Blame Games in Reflexive Discrimination Law
No full textThis paper examines the upcoming commencement of the 'socio-economic duty' in Section 1 of the Equality Act 2010 in England. The duty, which requires certain public bodies to have 'due regard' to reducing inequalities from socio-economic disadvantage when making strategic decisions, is part of a longer-standing 'reflexive turn' in discrimination law. Drawing on qualitative data from 267 civil servants and a survey experiment with a further 432, this paper explores what English civil servants think about reflexive discrimination law. The paper argues that engagement with the 'blame avoidance' literature can help to understand their attitudes. Drawing blame avoidance research, the paper argues that without adequate resources and enforcement, the socio-economic duty will be less likely to reduce socio-economic inequality and more likely to trigger blame games between central government and the public authorities subject to the duty
Cost-effectiveness of early surgical fixation versus cast immobilization for adults with a scaphoid waist fracture:five-year follow-up of the Scaphoid Waist Internal Fixation for Fractures Trial
Get PDFAIMS: The conclusion of the one-year analysis of the Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT) was that initial cast immobilization with surgical fixation for nonunion was the optimal treatment for patients with a fracture of the waist of the scaphoid. However, there remained significant uncertainty about the medium-term outcomes and how these could influence the patient's health-related quality of life (HRQoL), care requirements, and costs. The aim of this study was to explore how additional data from the five-year follow-up influenced the cost-effectiveness of the treatment of these fractures. METHODS: The analysis presents the patient-reported HRQoL, measured with the EuroQol five-dimension three-level health questionnaire, and the use of healthcare resources at five years after randomization, and considers which factors influenced the results. The original analytical model, in which the implications of the different forms of treatment throughout the patient's life were estimated, was also updated. RESULTS: Five years after randomization, most patients in both groups returned to the HRQoL level which is consistent with age-adjusted norms and did not require further healthcare. In contrast, those who continued to have clinically relevant adverse events at five years reported significantly worse HRQoL scores and greater care needs. It was also confirmed in the updated model that initial cast immobilization was the most cost-effective strategy, with a mean cost to the health system of £1,606 less per eligible patient compared with those who initially underwent surgery, an annual saving of £7.5 million. CONCLUSION: Most patients had no long-term impact from the injury regardless of the form of treatment. However, the few who had clinically defined adverse events at five years had poor HRQoL and greater care needs. The limited difference in these clinical outcomes between the two groups informed the findings of the decision model that, over the patient's lifetime, the small quality-adjusted life year gains for those who underwent surgery initially were not sufficient to justify the higher costs. These findings confirm that initial immobilization in a cast with fixation for nonunion is the optimal form of treatment for these patients
AC loss calculation for Litz wire windings in electrical machines
Get PDFHigh-frequency operation of electrical machines leads to excessive AC losses in the windings due to skin and proximity effects. To mitigate these losses, multistrand windings or Litz wire windings can be employed. This paper explores the applicability of the direct finite element (FE) method and two computationally efficient approaches—the homogenization technique and the FE-based dB/dt technique—for predicting Litz wire AC losses in electrical machines. Experimental validation is conducted using a motorette model with different configurations. Based on the dB/dt technique, a fast sweep method is proposed for AC loss calculation across various Litz wire specifications. This method efficiently scales with variations in working points, enabling the optimal design of Litz wire over a working cycle to minimize winding losses in a computationally efficient manner
Caring for and caring about in economic evaluation: modelling the family and caregiving effects
Get PDFCurrent methods for modelling spillover effects on carers in economic evaluation include four main methods: (absolute) utilities, disutilities, increments and multipliers. Each of these approaches assumes that the spillover effect is one-dimensional. We aimed to develop a new approach that better reflects the complexity of caring and the nuances of how a new treatment may impact the caregiver. We propose a new method based on the established concepts of the ‘family effect’ (or caring about someone) and the ‘caregiving effect’ (providing care for someone). These effects can be disentangled through analysis of carer-patient dyads or using patient and carer (dis)utilities and estimates from the literature. We consider case studies in Duchenne Muscular Dystrophy, Spinal Muscular Atrophy and Alzheimer’s Disease. Our approach models a small carer health-related quality of life (HRQoL) gain for each intervention, whereas the utility approach consistently models a substantial carer HRQoL gain, and the disutility approach models a carer HRQoL loss in two case studies. Our method allows explicit consideration of the benefits to carers of extending patient survival or improving patient health, with the negative HRQoL impact of increased caregiving burden. We propose that our method can be used with published data at present, and further research should analyse the family and caregiving effects in different conditions
Targeting angiogenesis and white matter repair for enhanced functional recovery after acute ischemic stroke: a focus on the roles of glial cells
No full textNeural network connections require adequate blood flow to deliver sufficient oxygen and glucose. Acute ischemic stroke (AIS) significantly impairs neural function due to insufficient blood flow, leading to diffuse microvascular dysfunction and compromised white matter integrity, both indicators of poor prognosis. Post-stroke neural recovery hinges on promoting neovascularization around the infarct and restoring white matter integrity. Therefore, strategies to enhance angiogenesis and white matter repair are crucial for post-stroke neuro-rehabilitation. Emerging research highlights the pivotal roles of activated microglia, astrocytes, and oligodendrocyte precursor cells in facilitating neurogenesis, angiogenesis, and neural functional recovery following cerebral ischemia. In this review, we explore the mechanisms by which these neuroglial cells contribute to angiogenesis and white matter repair after AIS. We also propose potential therapeutic strategies that target the intricate interactions at the glial cell-endothelial cell interface. A deeper understanding of oligovascular signaling in ischemic conditions could unveil novel therapeutic targets for improving outcomes after AIS
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇