LEED Study Research Articles

P1021 Comparison of subcutaneous and intravenous infliximab in patients with inflammatory bowel disease showed no differences in immunogenicity or treatment persistence at one year

Abstract Background The effectiveness of infliximab (IFX) in inflammatory bowel disease (IBD) can be impaired by the formation of anti-drug antibodies (ADA). Subcutaneous (SC) IFX has a different pharmacokinetic profile compared to intravenous (IV) administration. These differences may affect the risk of immunogenicity and we sought to explore this in a retrospective study. Methods We performed a retrospective study in Leeds, United Kingdom. Adult patients starting IFX for the first time between January 2019 and June 2022 were identified. All received standard induction with three IV doses followed by either: 1) maintenance SC IFX 2-weekly (standard practice from 2021), or 2) maintenance IV IFX (standard practice until 2021). We compared ADA levels, IFX trough levels and treatment persistence between groups after 12-months of treatment. ADA levels above 10 AU/ml were considered positive and ADA levels above 50 AU/ml as clinically relevant. Results After excluding 41 patients (16 stopped IFX after IV induction, 24 moved to SC after >4 IV doses, and 1 lost to follow-up), 101 patients receiving maintenance SC IFX were compared to 108 patients continuing with maintenance IV IFX. At 12-months, prevalence of ADA positivity was similar in both groups (48.1% SC vs 50.6%; p=0.775). Clinically relevant ADA levels (>50 AU/ml) were also similar (21.1% SC vs 26.5% IV; p=0.481). Additionally, there were no statistically significant differences in terms of detectable IFX trough levels and treatment persistence after 12-months of treatment between the two groups. Patients receiving combination therapy with IFX and immunomodulators showed a significant reduction in ADA formation irrespective of the route of IFX administration. 34.8% of patients receiving combination therapy had detectable ADA compared to 65.2% receiving IFX monotherapy (OR 0.28 (95% CI 0.13-0.58; p=0.001)). Treatment persistence was also significantly higher in those receiving combination therapy compared with monotherapy at 12-months (73.3% vs. 51.9%; p=0.004). The proportion of patients with detectable drug levels at 12-months was also higher with combination therapy (91.3% vs. 72.7%; p=0.005). Conclusion There were no significant differences in ADA levels, IFX levels, and treatment persistence between the SC and IV routes of IFX administration after 12 months of treatment. Concurrent use of immunomodulators was associated with reduced immunogenicity and better treatment persistence regardless of the route of maintenance IFX. Clinicians should advise patients on the benefits of immunomodulator combination therapy when initiating IFX regardless of route of administration.

Examining The Potential Efficacy Of An Incentive-based Mhealth Application: A Proof-of-concept Study In Leeds, Uk

Examining The Potential Efficacy Of An Incentive-based Mhealth Application: A Proof-of-concept Study In Leeds, Uk

Quasicrystal approximants in the two-dimensional Ba-Ti-O system on Pd(111): A LEED, XPS, and STM study

Long-range aperiodically ordered dodecagonal oxide quasicrystals (OQCs) have been observed on Pt(111), together with a variety of related approximants. All structures contain barium, titanium, and oxygen atoms in ${\mathrm{Ti}}_{n}{\mathrm{O}}_{n}$ ring structures with rings of $n$ = 4, 7, and 10. Barium decorates the larger rings and forms a dodecagonal square-triangle-rhombus tiling. In contrast to these studies on Pt(111), we report here on Ba-Ti-O layers on Pd(111), which has a 1% smaller lattice constant than Pt(111). We find a series of quasicrystal approximants with unit cells consisting of up to 60 triangles, 22 squares, and eight rhombuses. The latter resembles the largest quasicrystal approximant reported to date. The basis for these structures are local patches of the $\ensuremath{\sigma}$-phase square-triangle approximant, into which rhombuses are incorporated due to the formation of ordered antiphase domain boundaries in two orthogonal directions. A structural phase diagram of all quasicrystal approximants on Pd(111) system is presented.

Evolution of geometric and electronic structures of oxygen-induced superstructures on Mo(110) surface: A LEED, ARPES, and DFT study

We have studied the evolution of atomic structure and electronic band dispersion of oxygen-induced superstructures on the Mo(110) surface by using low-energy electron diffraction, angle-resolved photoemission spectroscopy, and density functional theory. Our experiments show that adsorption of oxygen at an elevated temperature (473 K) gets rid of the mixed-phase coexisting region observed at room temperature and exhibits three distinct superstructures: $p(2\ifmmode\times\else\texttimes\fi{}2$), $p(2\ifmmode\times\else\texttimes\fi{}1$), and $p(2\ifmmode\times\else\texttimes\fi{}6$) phases. Oxygenation of the Mo(110) surface leads to a confinement-induced gaplike opening at the zone center that can be tuned by the overlayer oxygen coverage. The ``hole'' pockets on the Fermi surface of the clean Mo(110) surface are found to persist upon oxygen adsorption with slightly changed volumes, while the ``electron'' pocket does not show any significant shift in momentum with no Fermi surface nesting behavior until saturation oxygen coverages. Apart from the significant modifications to the electronic states of the clean Mo(110) surface, we also observe the formation of new oxygen-induced bands. The evolution of the surface states near ${E}_{F}$ can be attributed to a change in the surface potential, while the evolution of oxygen-induced bands results from the hybridization between O-$2p\phantom{\rule{4pt}{0ex}}({m}_{j}=1/2$) and Mo-$4d$ (${m}_{j}=1/2$) orbitals at the interface. The interlayer separation, bond length, and lateral repulsive interactions between the adatoms are found to play a crucial role in the selective chemisorption of the Mo(110) surface.

Imaging three phases of iodine on Ag (111) using low-temperature scanning tunneling microscopy

We investigated the adsorption of iodine on Ag (111) in ultra-high vacuum. Using low-temperature scanning tunneling microscopy (LT-STM) measurements we catalog the complex surface structures on the local scale. We identified three distinct phases at various iodine coverage which we tentatively associate with three phases previously reported in LEED experiments ((3×3)R30∘, triangular, hexagonal). We used Fourier-space and real-space analysis to fully characterize each phase. While Fourier analysis most easily connects our measurements to previous LEED studies, the real-space inspection reveals local variations in the superstructures of the hexagonal and triangular phase. The latter, observed here for the first time by LT-STM, appears to be stabilized by one or two adatoms sitting at the center of a rosette-like iodine reconstruction. The most stunning discovery is that variation in the adatom separation of the triangular phase reflects the Ag (111) surface lattice.

A data flow process for confidential data and its application in a health research project.

The use of linked healthcare data in research has the potential to make major contributions to knowledge generation and service improvement. However, using healthcare data for secondary purposes raises legal and ethical concerns relating to confidentiality, privacy and data protection rights. Using a linkage and anonymisation approach that processes data lawfully and in line with ethical best practice to create an anonymous (non-personal) dataset can address these concerns, yet there is no set approach for defining all of the steps involved in such data flow end-to-end. We aimed to define such an approach with clear steps for dataset creation, and to describe its utilisation in a case study linking healthcare data. We developed a data flow protocol that generates pseudonymous datasets that can be reversibly linked, or irreversibly linked to form an anonymous research dataset. It was designed and implemented by the Comprehensive Patient Records (CPR) study in Leeds, UK. We defined a clear approach that received ethico-legal approval for use in creating an anonymous research dataset. Our approach used individual-level linkage through a mechanism that is not computer-intensive and was rendered irreversible to both data providers and processors. We successfully applied it in the CPR study to hospital and general practice and community electronic health record data from two providers, along with patient reported outcomes, for 365,193 patients. The resultant anonymous research dataset is available via DATA-CAN, the Health Data Research Hub for Cancer in the UK. Through ethical, legal and academic review, we believe that we contribute a defined approach that represents a framework that exceeds current minimum standards for effective pseudonymisation and anonymisation. This paper describes our methods and provides supporting information to facilitate the use of this approach in research.

Research on the Selection of Path Planning Algorithm: A Case Study in Leeds

Path planning algorithms are the core of path planning technology, and different path planning algorithms have different performances in terms of search efficiency and planning efficiency in different application areas. The traditional path planning algorithm selection mainly relies on personal knowledge and experience and takes a qualitative analysis method. With the variety of path planning algorithms and the increase of environmental complexity, the limitations of this empirical method are more and more obvious, and it is difficult to meet the actual needs of path planning and achieve the ideal path planning effect. The selection of path planning algorithms is an evaluation problem involving multiple factors and requires comprehensive algorithm selection and analysis. This paper addresses the problems of the selection method of the path planning algorithm, applies uncertainty theory and multi-attribute decision theory, constructs an evaluation system for path planning algorithm selection, proposes a multi-criteria EV-VIKOR decision model and decision method for path planning algorithm selection, and combines the results show the effectiveness of the decision-making method proposed in this paper.

Efficient Electrocatalytic CO2 Reduction to C2+ Alcohols at Defect-Site-Rich Cu Surface

Summary Electrochemical CO2 reduction is a promising approach for upgrading excessive CO2 into value-added chemicals, while the exquisite control of the catalyst atomic structures to obtain high C2+ alcohol selectivity has remained challenging due to the intrinsically favored ethylene pathways at Cu surface. Herein, we demonstrate a rational strategy to achieve ∼70% faradaic efficiency toward C2+ alcohols. We utilized a CO-rich environment to construct Cu catalysts with stepped sites that enabled high surface coverages of ∗CO intermediates and the bridge-bound ∗CO adsorption, which allowed to trigger CO2 reduction pathways toward the formation alcohols. Using this defect-site-rich Cu catalyst, we achieved C2+ alcohols with partial current densities of > 100 mA·cm−2 in both a flow-cell electrolyzer and a membrane electrode assembly (MEA) electrolyzer. A stable alcohol faradaic efficiency of ∼60% was also obtained, with ∼500 mg C2+ alcohol production per cm2 catalyst during a continuous 30-h operation.

I–V LEED study of Neodymium adsorption on W(110) at submonolayer coverage

The adsorption of neodymium (Nd) atoms on W(110) surface was studied by means of the LEED, AES and work function change measurements. It was found out, that Nd atoms form a set of dilute chain structures at coverages below 1 ML similarly to previously investigated rare earth metals (REM) adsorbed on Mo(110). The absence of particular fractional diffraction proved that the atoms in dilute chain structures form a zigzag not only in the case of the Mo(110) substrate but also for adsorption of REM on W(110). As a result of the glide plane symmetry considerations a modified model was proposed with a different configuration of adatoms in the unit cell of the surface forming the zigzag. To support the new hypothesis an I–V LEED analysis was made for the (6 × 2) Nd/W(110) dilute chain system. Several theoretical structures were tested in dynamical scattering simulations, including a centered structure with inequivalent adsorption sites in consecutive chains and a zigzag chain previously discussed in the literature. Ultimately the I–V LEED experiment validated a new modified zigzag chain model.

Development and external validation study of a melanoma risk prediction model incorporating clinically assessed naevi and solar lentigines.

Melanoma risk prediction models could be useful for matching preventive interventions to patients' risk. To develop and validate a model for incident first-primary cutaneous melanoma using clinically assessed risk factors. We used unconditional logistic regression with backward selection from the Australian Melanoma Family Study (461 cases and 329 controls) in which age, sex and city of recruitment were kept in each step, and we externally validated it using the Leeds Melanoma Case-Control Study (960 cases and 513 controls). Candidate predictors included clinically assessed whole-body naevi and solar lentigines, and self-assessed pigmentation phenotype, sun exposure, family history and history of keratinocyte cancer. We evaluated the predictive strength and discrimination of the model risk factors using odds per age- and sex-adjusted SD (OPERA) and the area under curve (AUC), and calibration using the Hosmer-Lemeshow test. The final model included the number of naevi ≥2mm in diameter on the whole body, solar lentigines on the upper back (a six-level scale), hair colour at age 18 years and personal history of keratinocyte cancer. Naevi was the strongest risk factor; the OPERA was 3·51 [95% confidence interval (CI) 2·71-4·54] in the Australian study and 2·56 (95% CI 2·23-2·95) in the Leeds study. The AUC was 0·79 (95% CI 0·76-0·83) in the Australian study and 0·73 (95% CI 0·70-0·75) in the Leeds study. The Hosmer-Lemeshow test P-value was 0·30 in the Australian study and <0·001 in the Leeds study. This model had good discrimination and could be used by clinicians to stratify patients by melanoma risk for the targeting of preventive interventions. What's already known about this topic? Melanoma risk prediction models may be useful in prevention by tailoring interventions to personalized risk levels. For reasons of feasibility, time and cost many melanoma prediction models use self-assessed risk factors. However, individuals tend to underestimate their naevus numbers. What does this study add? We present a melanoma risk prediction model, which includes clinically-assessed whole-body naevi and solar lentigines, and self-assessed risk factors including pigmentation phenotype and history of keratinocyte cancer. This model performs well on discrimination, the model's ability to distinguish between individuals with and without melanoma, and may assist clinicians to stratify patients by melanoma risk for targeted preventive interventions.

Structure of a Zn monolayer on Ag(111) and Ag(110) substrates: An AES, LEED and STM study

Auger Electron Spectroscopy, Low Energy Electron Diffraction and Scanning Tunneling Microscopy have been used to study the atomic structure of a Zn monolayer deposited on Ag(111) and Ag(110) substrates at room temperature. On both faces, there is formation of a close packed monolayer of Zn covering the entire substrate surface and giving rise to specific Moiré patterns. From a comprehensive LEED and STM data analysis, we deduce that the Zn monolayer adopts a (111) structure equivalent to a pure Zn layer rotated with respect to the silver substrate, of about 1.5° on the Ag(111) face and of about 4.5° on the Ag(110) face giving rise respectively to (√156x√156)R18° and c(12 × 6) superstructures.

City‐wide emissions modelling using fleet probe vehicles

Five UK cities will implement clean air zones to improve air quality (AQ), specifically in relation to oxides of nitrogen, and 253 UK local authorities have declared AQ management areas. Extended range electric vehicles can offer zero emission (ZE) operation but cities lack the ability to monitor and control when vehicles can switch from engine to battery. Project Autonomous and Connected vehicles for CleaneR Air (ACCRA) aims to develop and demonstrate a system allowing hybrid vehicle to become part of a city's urban traffic management control system; monitoring the vehicles’ location and operational state, and controlling the strategy to ensure ZE operation through geofenced zones with poor AQ. This study demonstrates a new methodology to model emissions using state-of-the-art instantaneous vehicle emissions modelling, geographic information system (GIS) and a new method for capturing vehicle behaviour using global positioning system. Probe vehicles were used for the pilot study in Leeds, UK, to capture drive-cycle data and the emissions are modelled. A GIS interface is used to match these emissions to the network. Finally, a high-resolution emissions map is generated to be used as input for AQ dispersion models and the ACCRA decision-making engine for the generation of geofencing AQ zones.

Growth optimization and electronic structure of ultrathin CoO films on Ag(001): A LEED and photoemission study

We present here a detailed growth optimization of CoO thin film on Ag(001) involving the effects of different growth parameters on the electronic structure. A well-ordered stoichiometric growth of 5 ML CoO film has been observed at 473 K substrate temperature and 1 × 10−6 mbar oxygen partial pressure. The growth at lower substrate temperature and oxygen partial pressure show non-stoichiometric impurity phases which have been investigated further to correlate the growth parameters with surface electronic structure. The coverage dependent valence band electronic structure of the films grown at optimized condition reveals the presence of interfacial states near the Fermi edge (EF) for lower film coverages. Presence of interfacial states in the stoichiometric films rules out their defect-induced origin. We argue that this is an intrinsic feature of transition metal monoxides like NiO, CoO, MnO in the low coverage regime.

Is dietary macronutrient composition during pregnancy associated with offspring birth weight? An observational study.

There is lack of evidence on the differential impact of maternal macronutrient consumption: carbohydrates (CHO), fats and protein on birth weight. We investigated the association between maternal dietary macronutrient intakes and their sub-components such as saccharides and fatty acids and birth weight. This analyses included 1,196 women with singleton pregnancies who were part of the CAffeine and REproductive health study in Leeds, UK between 2003 and 2006. Women were interviewed in each trimester. Dietary information was collected twice using a 24-h dietary recall about 8-12 weeks and 13-27 weeks of gestation. Multiple linear regression models adjusted for alcohol and smoking in trimester 1, showed that each additional 10 g/d CHO consumption was associated with an increase of 4 g (95 % CI 1, 7; P=0·003) in birth weight. Conversely, an additional 10 g/d fat intake was associated with a lower birth weight of 8 g (95 % CI 0, 16; P=0·04) when we accounted for energy contributing macronutrients in each model, and maternal height, weight, parity, ethnicity, gestational age at delivery and sex of the baby. There was no evidence of an association between protein intake and birth weight. Maternal diet in trimester 2 suggested that higher intakes of glucose (10 g/d) and lactose (1 g/d) were both associated with higher birth weight of 52 g (95 % CI 4, 100; P=0·03) and 5 g (95 % CI 2, 7; P<0·001) respectively. These results show that dietary macronutrient composition during pregnancy is associated with birth weight outcomes. An appropriately balanced intake of dietary CHO and fat during pregnancy could support optimum birth weight.

Honeycomb BeO monolayer on the Mo(112) surface: LEED and DFT study

Abstract From the combined experimental and theoretical investigations, we suggest the formation of a honeycomb structure of BeO monolayer on the Mo(112) surface. This structure is matched to the substrate Mo(112), thus giving the (1 × 1) LEED pattern, and its formation is confirmed also by DFT calculations and work function measurements. While a free BeO monolayer is dielectric, the BeO/Mo(112) system is definitely metallic as follows from the bands crossing EF and significant density of states at EF. The honeycomb BeO monolayer is bound to the Mo(112) surface through O atoms situated atop Mo atoms of the surface rows. A substantial rigidity of the BeO monolayer leads to the appearance of empty space above the Mo(112) surface furrows, which may be filled by some gas or water molecules. Hence, this layered system can be very attractive in various applications where porous materials are explored (e.g. for hydrogen storage purposes).

Stages of Se adsorption on Au(111): A combined XPS, LEED, TOF-DRS, and DFT study

We have studied the adsorption of Se on the surface Au(111) using XPS, TOF-DRS, LEED and DFT calculations. The use of a doser that operates in vacuum allowed us to investigate all the stages of the adsorption from the clean surface up to the formation of multilayers. In the monolayer regime we have found two ordered phases with distinctive LEED patterns. The LEED pattern of the first phase presents three fractional spots arranged symmetrically around the positions of the spots in a √3x√3 pattern. The analysis of this pattern suggests the formation of either a nxn superstructure of √3x√3 domains with n=19 or n=22, or that the adsorption occurs without removing the 22x√3 herringbone reconstruction of the gold surface. This last possibility is in accordance with DFT calculations which show that the charge transfer to a Se adsorbate might not be enough to destabilize the surface reconstruction. Increasing the coverage, beyond 0.3ML a new LEED pattern appears with broad spots which upon annealing at 150°C become well defined indicating a 1×8 periodicity. At the highest doses we have observed the formation of multilayers with no discernible LEED pattern. The comparison with adsorption experiments carried out in liquid solutions show similarities and also some important differences.

A revisit to ultrathin NiO(0 0 1) film: LEED and valence band photoemission studies

LEED and photoemission measurements have been performed on ultrathin NiO films to reinvestigate its surface quality and valence electronic structures, respectively. On Ag(001) substrate, the best epitaxial order was observed for high temperature deposition with sufficient oxygen flux associated with a post-deposition oxygen annealing. The effect of the substrate vicinity on valence band electronic structure, in case of interfacial NiO layers, has been explained. The variation of Ni 3d to O 2p photoemission cross-section with photon energy (hν) has been demonstrated in this work.

Lived Realities of Local Community: Evidence from a Qualitative Case Study in Leeds

This article draws on case study research of a low-income neighbourhood in Leeds to explore experiences of, and attitudes towards, place-based community. Through tracing social relations in the neighbourhood over time, from the early twentieth century to the present day, the ways in which community is embedded in everyday activities and social interactions, and the social impact of socioeconomic change on local neighbourhoods, is demonstrated. It is argued that the relentless and nostalgic focus on local communities as an idealised form of social solidarity has meant that the reasons why place-based community has declined over time have been overlooked. The article challenges the assumption that social fragmentation on neighbourhood levels necessarily indicates antisocial trends or a lack of a sense of duty towards others, and draws attention to the constraints people face in developing relationships with others. Questions are raised about the viability of top-down attempts to shape social relations in particular ways.

LEED studies on modulated surface structures

Abstract The problems occurring in structure analyses of modulated surfaces by LEED or X-ray diffraction are briefly discussed. In previous LEED studies of modulated surfaces a commensurate unit cell and Fourier coefficients to describe the modulation function has been used. The wave length of the modulation and the size of the supercell are limited in this way by the computational effort of the multiple scattering calculations. To overcome this problem an approximation is proposed allowing the analysis of commensurate or incommensurate surface modulations with long wave lengths.

Genome-wide association study of L-arginine and dimethylarginines reveals novel metabolic pathway for symmetric dimethylarginine.

Dimethylarginines (DMA) interfere with nitric oxide formation by inhibiting nitric oxide synthase (asymmetrical DMA [ADMA]) and l-arginine uptake into the cell (ADMA and symmetrical DMA [SDMA]). In prospective clinical studies, ADMA has been characterized as a cardiovascular risk marker, whereas SDMA is a novel marker for renal function and associated with all-cause mortality after ischemic stroke. The aim of the current study was to characterize the environmental and genetic contributions to interindividual variability of these biomarkers. This study comprised a genome-wide association analysis of 3 well-characterized population-based cohorts (Framingham Heart Study [FHS; n=2992], Gutenberg Health Study [GHS; n=4354], and Multinational Monitoring of Trends and Determinants in Cardiovascular Disease Study [MONICA]/Cooperative Health Research in the Augsburg Area, Augsburg, Bavaria, Germany [KORA] F3 [n=581]) and identified replicated loci (DDAH1, MED23, Arg1, and AGXT2) associated with the interindividual variability in ADMA, l-arginine, and SDMA. Experimental in silico and in vitro studies confirmed functional significance of the identified AGXT2 variants. Clinical outcome analysis in 384 patients of the Leeds stroke study demonstrated an association between increased plasma levels of SDMA, AGXT2 variants, and various cardiometabolic risk factors. AGXT2 variants were not associated with poststroke survival in the Leeds study or were they associated with incident stroke in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. These genome-wide association study support the importance of DDAH1 and MED23/Arg1 in regulating ADMA and l-arginine metabolism, respectively, and identify a novel regulatory renal pathway for SDMA by AGXT2. AGXT2 variants might explain part of the pathogenic link between SDMA, renal function, and outcome. An association between AGXT2 variants and stroke is unclear and warrants further investigation.