Surface Density Research Articles

Revealing Spatial Molecular Heterogeneity of High-Density Biofunctionalized Surfaces Using DNA-PAINT.

The quantification and control of molecular densities and distributions on biofunctionalized surfaces are key for enabling reproducible functions in biosciences. Here, we describe an analysis methodology for quantifying the density and spatial distribution of high-density biofunctionalized surfaces, with densities in the order of 102-105 biomolecules per μm2 area, in a short measurement time. The methodology is based on single-molecule DNA-PAINT imaging combined with simulation models that compensate for lifetime and spatial undersampling effects, resulting in three distinct molecule counting methods and a statistical test for spatial distribution. The analysis methodology is exemplified for a surface with ssDNA affinity binder molecules coupled to a PLL-g-PEG antifouling coating. The results provide insights into the biofunctionalization efficiency, yield, and homogeneity. Furthermore, the data reveal that heterogeneity is inherent to the biofunctionalization process and shed light on the underlying molecular mechanisms. We envision that DNA-PAINT imaging with the developed analysis framework will become a versatile tool to study spatial heterogeneity of densely biofunctionalized surfaces for a wide range of applications.

Plasma Etch of IGZO Thin Film and IGZO/SiO2 Interface Diffusion in Inductively Coupled CH4/Ar Plasmas

ABSTRACTIn this work, the etching characteristics of InGaZnO4 (IGZO) thin films were systemically investigated in inductively coupled CH4/Ar plasmas with various gas ratios, bias voltages, and surface temperatures. The ion flux in the CH4/Ar plasmas was analyzed using bias power and voltage, whereas the relative densities of CH and H radicals were quantified through optical actinometry. The change in CH3 radical density was also estimated based on plasma kinetics analysis. The correlations between the plasma properties and IGZO etch rate were investigated. In CH4/Ar plasmas with CH4 ratios below 80%, the IGZO etch rate increases with a higher CH4 proportion, aligning with the ascending trend of CH3 radical density, which suggests that CH3 radical density acts as a limiting factor (radical‐limited regime). However, the IGZO etch rate decreases when the CH4 ratio exceeds 80%, corresponding to the reduction in ion flux, which indicates that ion flux becomes a limiting factor in this ion‐limited regime. The IGZO etch rate shows a linear relationship with bias voltage and follows the Arrhenius equation with varying surface temperature in plasmas without bias voltage. A spontaneous etch model was proposed based on these relationships. In this model, the IGZO etch rate depends on CH3 radical density and IGZO surface reactivity, where ion bombardment contributes more significantly to surface reactivity than high surface temperature. IGZO thin film was deposited on SiO2 during the fabrication of a 3D stacked ferroelectric field‐effect transistor (FeFET) memory device. The interaction between IGZO and SiO2 during CH4/Ar plasma processing was investigated using time‐of‐flight secondary ion mass spectrometry. The efficacy of removing IGZO atoms that had diffused into the SiO2 network was enhanced when subjected to plasma with a bias voltage, compared to the process without a bias voltage. However, exposure to CH4/Ar plasma resulted in a deeper diffusion of IGZO atoms into the SiO2 network, primarily attributed to ion bombardment rather than elevated surface temperature. A significant improvement in surface smoothness was achieved after IGZO and SiO2 etch by introducing BCl3 into the SiO2 etching chemistry.

Quantitative Analysis of Protein-Protein Equilibrium Constants in Cellular Environments Using Single-Molecule Localization Microscopy.

Current methods for determining equilibrium constants often operate in three-dimensional environments, which may not accurately reflect interactions with membrane-bound proteins. With our technique, based on single-molecule localization microscopy (SMLM), we directly determine protein-protein association (Ka) and dissociation (Kd) constants in cellular environments by quantifying associated and isolated molecules and their interaction area. We introduce Kernel Surface Density (ks-density,) a novel method for determining the accessible area for interacting molecules, eliminating the need for user-defined parameters. Simulation studies validate our method's accuracy across various density and affinity conditions. Applying this technique to T cell signaling proteins, we determine the 2D association constant of T cell receptors (TCRs) in resting cells and the pseudo-3D dissociation constant of pZAP70 molecules from phosphorylated intracellular tyrosine-based activation motifs on the TCR-CD3 complex. We address challenges of multiple detection and molecular labeling efficiency. This method enhances our understanding of protein interactions in cellular environments, advancing our knowledge of complex biological processes.

Radial properties of dust in galaxies: Comparison between observations and isolated galaxy simulations

We study the importance of several processes that influence the evolution of dust and its grain size distribution on spatially resolved scales in nearby galaxies. Here, we compiled several multi-wavelength observations for the nearby galaxies NGC\,628 (M74), NGC\,5457 (M101), NGC\,598 (M33), and NGC 300. We applied spatially resolved spectral energy distribution (SED) fitting to the latest iteration of infrared data to get constraints on the galaxy dust masses and the small-to-large grain abundance ratio (SLR). We separated each galaxy into radial rings and obtained the radial profiles of the properties mentioned above. For comparison, we took the radial profiles of the stellar mass and gas mass surface density for NGC\,628 combined with its metallicity gradient in the literature to calibrate a single-galaxy simulation using the GADGET4-OSAKA code. The simulations include a parametrization to separate the dense and diffuse phases of the ISM where different dust-evolution mechanisms are in action. We find that our simulation can reproduce the radial profile of dust mass surface density but overestimates the SLR in NGC\,628. Changing the dust-accretion timescale has little impact on the dust mass or SLR, as most of the available metals are accreted onto dust grains at early times ($<3$\,Gyr), except in the outer regions of the galaxy where the metallicity is below $2 $. This suggests we can only constrain the accretion timescale of galaxies at extremely low metallicities where accretion still competes with other mechanisms controlling the dust budget. The overestimation of the SLR likely results from (i) overly efficient shattering processes in the diffuse interstellar medium (ISM), which were calibrated to reproduce Milky Way-type galaxies and/or (ii) our use of a diffuse and dense gas density subgrid model that does not entirely capture the intricacies of the small-scale structure present in NGC\,628. We conclude that future modeling efforts will need to focus on improving the subgrid recipes to mimic the multi-phase gas distribution in galaxies before the efficiency of dust evolution processes can be calibrated for galaxies other than the Milky Way.

Multi-modal characterisation of early-stage, subclinical cardiac deterioration in patients with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) is a major risk factor for heart failure with preserved ejection fraction and cardiac arrhythmias. Precursors of these complications, such as diabetic cardiomyopathy, remain incompletely understood and underdiagnosed. Detection of early signs of cardiac deterioration in T2DM patients is critical for prevention. Our goal is to quantify T2DM-driven abnormalities in ECG and cardiac imaging biomarkers leading to cardiovascular disease. We quantified ECG and cardiac magnetic resonance imaging biomarkers in two matched cohorts of 1781 UK Biobank participants, with and without T2DM, and no diagnosed cardiovascular disease at the time of assessment. We performed a pair-matched cross-sectional study to compare cardiac biomarkers in both cohorts, and examined the association between T2DM and these biomarkers. We built multivariate multiple linear regression models sequentially adjusted for socio-demographic, lifestyle, and clinical covariates. Participants with T2DM had a higher resting heart rate (66 vs. 61 beats per minute, p < 0.001), longer QTc interval (424 vs. 420ms, p < 0.001), reduced T wave amplitude (0.33 vs. 0.37mV, p < 0.001), lower stroke volume (72 vs. 78ml, p < 0.001) and thicker left ventricular wall (6.1 vs. 5.9mm, p < 0.001) despite a decreased Sokolow-Lyon index (19.1 vs. 20.2mm, p < 0.001). T2DM was independently associated with higher heart rate (beta = 3.11, 95% CI = [2.11,4.10], p < 0.001), lower stroke volume (beta = -4.11, 95% CI = [-6.03, -2.19], p < 0.001) and higher left ventricular wall thickness (beta = 0.133, 95% CI = [0.081,0.186], p < 0.001). Trends were consistent in subgroups of different sex, age and body mass index. Fewer significant differences were observed in participants of non-white ethnic background. QRS duration and Sokolow-Lyon index showed a positive association with the development of cardiovascular disease in cohorts with and without T2DM, respectively. A higher left ventricular mass and wall thickness were associated with cardiovascular outcomes in both groups. T2DM prior to cardiovascular disease was linked with a higher heart rate, QTc prolongation, T wave amplitude reduction, as well as lower stroke volume and increased left ventricular wall thickness. Increased QRS duration and left ventricular wall thickness and mass were most strongly associated with future cardiovascular disease. Although subclinical, these changes may indicate the presence of autonomic dysfunction and diabetic cardiomyopathy.

Effects of nitrogen vacancy sites of oxynitride support on the catalytic activity for ammonia decomposition

Nitrogen-containing compounds such as imides and amides have been reported as efficient materials that promote ammonia decomposition over nonnoble metal catalysts. However, these compounds decompose in an air atmosphere and become inactive, which leads to difficulty in handling. Here, we focused on perovskite oxynitrides as air-stable and efficient supports for ammonia decomposition catalysts. Ni-loaded oxynitrides exhibited 2.5–18 times greater catalytic activity than did the corresponding oxide-supported Ni catalysts, even without noticeable differences in the Ni particle size and surface area of the supports. The catalytic performance of the Ni-loaded oxynitrides is well correlated with the nitrogen desorption temperature during N2 temperature-programmed desorption, which suggests that the lattice nitrogen in the oxynitride support rather than the Ni surface is the active site for ammonia decomposition. Furthermore, NH3 temperature-programmed surface reactions and density functional theory (DFT) calculations revealed that NH3 molecules are preferentially adsorbed on the nitrogen vacancy sites on the support surface rather than on the Ni surface. Thus, the ammonia decomposition reaction is facilitated by a vacancy-mediated reaction mechanism.

Semantic Segmentation Uncertainty Assessment of Different U-net Architectures for Extracting Building Footprints

Abstract. Automatic extraction of building footprints from aerial and space imageries has been found ever increasing importance in urban planning, disaster management, and environmental monitoring. However, achieving accurate building footprint extraction poses significant challenges due to diverse building characteristics and their similarities to their background elements. While conventional methods in building footprint extraction have mainly relied on image processing techniques, recent advancements in deep learning, particularly semantic segmentation algorithms like U-Net, have shown promise in addressing these challenges through machine learning. This study explores different depths of the U-Net model for building footprint extraction, aiming to identify the optimum architecture while investigating the semantic uncertainty of the building footprint extraction. Utilizing aerial imagery from cities including Berlin, Paris, Chicago, and Zurich, collected from Google Maps and OpenStreetMap (OSM) data, five U-Net models have been compared with varying depths. In addition, the impact of dataset sizes and learning rates on model performance has been investigated. Results confirmed that the U-Net-32-1024 model achieves the highest intersection over union (IoU), Accuracy, and F1-score. Moreover, increasing the training dataset size leads to significant improvements in model performance with IoU, Accuracy and F1-score reaching their values of 73.73%, 88.65% and 88.53%. However, challenges remain in accurately delineating buildings in dense urban areas. Nonetheless, our findings demonstrated the effectiveness of U-Net models in building footprint extraction.

A percolation-type criticality threshold controls immune protein coating of surfaces.

When a material enters the body, it is immediately attacked by hundreds of proteins, organized into complex networks of binding interactions and reactions. How do such complex systems interact with a material, "deciding" whether to attack? We focus on the "complement" system of ∼40 blood proteins that bind microbes, nanoparticles, and medical devices, initiating inflammation. We show a sharp threshold for complement activation upon varying a fundamental material parameter, the surface density of potential complement attachment points. This sharp threshold manifests at scales spanning single nanoparticles to macroscale pathologies, shown here for diverse engineered and living materials. Computational models show these behaviors arise from a minimal subnetwork of complement, manifesting percolation-type critical transitions in the complement response. This criticality switch explains the "decision" of a complex signaling network to interact with a material, and elucidates the evolution and engineering of materials interacting with the body.

Regulating the Pore Structure and Heteroatom Doping of Soybean Straw Carbon Based on a Bifunctional Template Method for the High-Performance Carbon Supercapacitor.

The previous research addressed the waste problem of agriculture and forestry residues by exploring the efficient utilization of liquefied soybean straw in supercapacitor. The structures of the liquefied soybean straw were controlled by coupling microwave hydrothermal treatment with carbonization under the influence of a C3N4 bifunctional template. What's more, C3N4 could effectively regulate the pore structures and provide an effective N active site of carbon materials C3N4. The obtained N-SLR Carbon-700 possess a specific surface area of up to 1593.7 m2 g -1, and the pore size is mainly concentrated in the range of 1.8-2.5 nm, providing efficient ions transmission channels and storage space. Its specific capacitance is up to 261.5 F g-1 (current density of 0.5 A g-1), and the capacity retention is 74.04 % when the current density is expanded by 20 times. In the two-electrode system, the energy density of N-SLR Carbon-700 could reach to 31.3 W h kg-1 at a power density of 360 W kg-1, as well as the energy surface density is maintained at 69 % when the power density is increased by a factor of 20. This work enhances effectively the charging and discharging stability and capacitance value of carbon-based supercapacitor.

Microvascular alterations of the ocular surface and retina in connective tissue disease-related interstitial lung disease.

To examine the disparities in macular retinal vascular density between individuals with connective tissue disease-related interstitial lung disease (CTD-ILD) and healthy controls (HCs) by optical coherence tomography angiography (OCTA) and to investigate the changes in microvascular density in abnormal eyes. For a retrospective case-control study, a total of 16 patients (32 eyes) diagnosed with CTD-ILD were selected as the ILD group. The 16 healthy volunteers with 32 eyes, matched in terms of age and sex with the patients, were recruited as control group. The macular retina's superficial retinal layer (SRL) and deep retinal layer (DRL) were examined and scanned using OCTA in each individual eye. The densities of retinal microvascular (MIR), macrovascular (MAR), and total microvascular (TMI) were calculated and compared. Changes in retinal vascular density in the macular region were analyzed using three different segmentation methods: central annuli segmentation method (C1-C6), hemispheric segmentation method [uperior right (SR), superior left (SL), inferior left (IL), and inferior right (IR)], and Early Treatment Diabetic Retinopathy Study (ETDRS) methods [superior (S), inferior (I), left (L), and right (R)]. The data were analyzed using Version 9.0 of GraphPad prism and Pearson analysis. The OCTA data demonstrated a statistically significant difference (P<0.05) in macular retinal microvessel density between the two groups. Specifically, in the SRL and DRL analyses, the ILD group exhibited significantly lower surface density of MIR and TMI compared to the HCs group (P<0.05). Furthermore, using the hemispheric segmentation method, the ILD group showed notable reductions in SL, SR, and IL in the superficial retina (P<0.05), as well as marked decreases in SL and IR in the deep retina (P<0.05). Similarly, when employing the ETDRS method, the ILD group displayed substantial drops in superficial retinal S and I (P<0.05), along with notable reductions in deep retinal L, I, and R (P<0.05). In the central annuli segmentation method, the ILD group exhibited a significant decrease in the superficial retinal C2-4 region (P<0.05), whereas the deep retina showed a notable reduction in the C3-5 region (P<0.05). Additionally, there was an observed higher positive likelihood ratio in the superficial SR region and deep MIR. Furthermore, there was a negative correlation between conjunctival vascular density and both deep and superficial retinal TMI (P<0.001). Patients with CTD-ILD exhibits a significantly higher conjunctival vascular density compared to the HCs group. Conversely, their fundus retinal microvascular density is significantly lower. Furthermore, CTD-ILD patients display notably lower superficial and deep retinal vascular density in comparison to the HCs group. The inverse correlation between conjunctival vascular density and both superficial and deep retinal TMI suggests that detecting subtle changes in ocular microcirculation could potentially serve as an early diagnostic indicator for connective tissue diseases, thereby enhancing disease management.

Plasma C-peptide mammographic features and risk of breast cancer

Our study in the Nurses’ Health Study (NHS) and NHS2, a nested case-control study with 1260 cases and 2221 controls, investigated the association between C-peptide levels, mammographic density (MD) parameters, V (a measure of gray scale variation), and breast cancer (BC) risk. We also examined how C-peptide and BC risk vary across quartiles of mammographic features. Linear and logistic regressions were used to study the associations between C-peptide and MD parameters, and breast cancer. C-peptide was inversely associated with percent MD and positively with non-dense area, but no associations were found with dense area and V measure. C-peptide was associated with an increased risk of invasive BC risk (top vs. bottom quartile, odds ratio = 1.46, 95% CI: 1.12–1.91). No multiplicative interactions were found between C-peptide, MD parameters, and BC risk. Our results suggest a positive association between C-peptide and BC risk, and MD parameters do not seem to modify this association.

Puerarin alleviates osteoporosis in rats by targeting the JAK2/STAT3 signaling pathway.

Osteoporosis (OP) is a common chronic progressive bone disease that increases fracture risk in postmenopausal women. Research suggests that puerarin (Pue) may be an effective treatment for OP. This study examined the effects and underlying mechanisms of Pue in treating postmenopausal osteoporosis (PMOP) in rats. Sprague-Dawley (SD) rats underwent bilateral ovariectomy to simulate PMOP and were then treated with subcutaneous injections of Pue. Bone mineral density (BMD) was measured using a bone densitometer. Micro-CT scans assessed femur bone structure and various parameters were calculated: bone volume fraction (BV/TV), bone surface density (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and bone surface area-to-bone volume ratio (BS/BV). Hematoxylin-eosin (HE) staining was employed to observe femoral tissue pathology. Serum levels of bone formation metabolism-related markers-osteocalcin (OC), bone alkaline phosphatase (BALP), and procollagen type I N-terminal propeptide (PINP)-were measured via enzyme-linked immunosorbent assay (ELISA). The protein expression levels of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in bone tissue were evaluated using Western blotting assay. The results showed improved bone density and reduced bone loss in rats treated with Pue. There were also significant increases in serum levels of OC and BALP, indicating enhanced osteogenesis. Furthermore, there was a decrease in activation of the JAK2/STAT3 pathway in femoral tissue, suggesting a pathway inhibition. These findings indicate that Pue may combat osteoporosis by promoting osteogenesis and inhibiting activation of the JAK2/STAT3 pathway activation.

Polar alignment of a dusty circumbinary disc–II. Application to 99 Herculis

ABSTRACT We investigate the formation of dust traffic jams in polar-aligning circumbinary discs. In our first paper, we found as the circumbinary disc evolves towards a polar configuration perpendicular to the binary orbital plane, the differential precession between the gas and dust components leads to multiple dust traffic jams. These dust traffic jams evolve to form a coherent dust ring. In part two, we use 3D smoothed particle hydrodynamical simulations of gas and dust to model an initially highly misaligned circumbinary disc around the 99 Herculis (99 Her) binary system. Our results reveal that the formation of these dust rings is observed across various disc parameters, including the disc aspect ratio, viscosity, surface density power-law index, and temperature power-law index. The dust traffic jams are long-lived and persist even when the disc is fully aligned polar. The midplane dust-to-gas ratio within the rings can surpass unity, which may be a favourable environment for planetesimal formation. Using 2D inviscid shearing box calculations with parameters from our 3D simulations, we find streaming instability modes with significant growth rates. The streaming instability growth time-scale is less than the tilt oscillation time-scale during the alignment process. Therefore, the dust ring will survive once the gas disc aligns polar, suggesting that the streaming instability may aid in forming polar planets around 99 Her.

Assessment of a multiphase formulation of one-dimensional turbulence using direct numerical simulation of a decaying turbulent interfacial flow

The interaction between turbulence and surface tension is studied numerically using the one-dimensional-turbulence (ODT) model. ODT is a stochastic model simulating turbulent flow evolution along a notional one-dimensional line of sight by applying instantaneous maps that represent the effects of individual turbulent eddies on property fields. It provides affordable high resolution of interface creation and property gradients within each phase, which are key for capturing the local behavior as well as overall trends, and has been shown to reproduce the main features of an experimentally determined regime diagram for primary jet breakup. Here ODT is used to investigate the interaction of turbulence with an initially planar interface. The notional flat interface is inserted into a periodic box of decaying homogeneous isotropic turbulence, simulated for a variety of turbulent Reynolds and Weber numbers. Unity density and viscosity ratios serve to focus solely on the interaction between fluid inertia and the surface-tension force. Statistical measures of interface surface density and spatial structure along the direction normal to the initial surface are compared to corresponding direct-numerical-simulation (DNS) data. Allowing the origin of the lateral coordinate system to follow the location of the median interface element improves the agreement between ODT and DNS, reflecting the absence of lateral nonvortical displacements in ODT. Beyond the DNS-accessible regime, ODT is shown to obey the predicted parameter dependencies of the Kolmogorov critical scale in both the inertial and dissipative turbulent-cascade subranges. Notably, the probability density function of local fluctuations of the critical scale is found to collapse to a universal curve across both subranges. Published by the American Physical Society 2024

Plastic mulching enhances maize yield and water productivity by improving root characteristics, green leaf area, and photosynthesis for different cultivars in dryland regions

Uneven precipitation during the growing season and frequent seasonal droughts on the Loess Plateau in Northwest China adversely affect crop production and water use efficiency. While plastic mulching (PM) has been used to alleviate water stress, few studies have examined the traits maize cultivars need to adapt to the altered water environment under PM and achieve high yields. A two-year field experiment was conducted to assess the root characteristics and aboveground growth traits of three widely used high-yielding maize cultivars—Zhengdan 958 (ZD), Huanong 138 (HN), Heboshi 122 (HBS)—under no mulching (NM) and PM conditions. Among the three cultivars, HBS had the highest root system indices—root length density (RLD), root surface area density (RSD), and root biomass—in the topsoil (0–40 cm), followed by ZD and HN under both NM and PM conditions. Under NM, HBS_NM treatment exhibited strong water absorption, improving photosynthesis and yield, making it suitable for drought conditions. Under PM, topsoil moisture increased significantly, with root system indices increasing by 22.5–36.1 % for RLD, 30.2–36.1 % for RSD, and 25.2–36.5 % for root biomass across the cultivars compared to NM. While ZD_PM did not have the highest root system indices under PM, it exhibited higher green leaf area index (4.5–7.5 %), chlorophyll content (2.8–8.6 %), and photosynthetic rate (6.0–14.5 %), resulting in the highest aboveground biomass and yield among the treatments. These findings suggest ZD is better adapted to the enhanced soil moisture under PM. Future research should focus on breeding genotypes that thrive under PM conditions, emphasizing traits such as larger leaf areas and higher photosynthetic rates to boost crop productivity in rainfed areas.

Low cost and real-time surveillance of enteric infection and diarrhoeal disease using rapid diagnostic tests in Cox’s Bazar, Bangladesh

BackgroundReal-time disease surveillance is an important component of infection control in at-risk populations. However, data on cases or from lab testing is often not available in many low-resource settings. Rapid diagnostic tests (RDT), including immunochromatographic assays, may provide a low cost, expedited source of infection data.MethodsWe conducted a pilot survey-based prevalence mapping study of enteric infection in Camp 24 of the camps for the forcibly displaced Rohingya population from Myanmar in Cox’s Bazar, Bangladesh. We randomly sampled the population and collected and tested stool from under-fives for eight pathogens using RDTs in January–March 2021 and September–October 2021. A Bayesian geospatial statistical model allowing for imperfect sensitivity and specificity of the tests was adapted.ResultsWe collected and tested 396 and 181 stools in the two data collection rounds. Corrected prevalence estimates ranged from 0.5% (Norovirus) to 27.4% (Giardia). Prevalence of Escherichia coli O157, Campylobacter, and Cryptosporidium were predicted to be higher in the high density area of the camp with relatively high probability (70–95%), while Adenovirus, Norovirus, and Rotavirus were lower in the areas with high water chlorination. Clustering of cases of Giardia and Shigella was also observed, although associated with relatively high uncertainty.ConclusionsWith an appropriate correction for diagnostic performance RDTs can be used to generate reliable prevalence estimates, maps, and well-calibrated uncertainty estimates at a significantly lower cost than lab-based studies, providing a useful approach for disease surveillance in these settings.

Land Use, Travel Patterns and Gender in Barcelona: A Sequence Analysis Approach

Transport systems are essential for the path toward sustainable urbanisation and the transition to more sustainable living. Recently, European cities have undergone substantial changes, and suburbanisation is posing new challenges. Suburban areas are often more affordable in terms of housing, but these neighbourhoods tend to be car-oriented. This leads to higher commuter costs, immobility, transport and time poverty, pollution, higher accident rates and a lack of social interactions. To offer sustainable mobility options to citizens, we must comprehensively understand, together with their individual characteristics, their specific mobility practices and the built environment where they live. This study is centred on the Barcelona Metropolitan Region, which has a public transport network that covers its entire area. The aim of this study is to examine the relationships between travel behaviour, transport mode use, individual characteristics and built environment characteristics in the place of residence using detailed information sources. Herein, we used data from the 2018 to 2021 annual travel survey conducted in the Barcelona region, together with land use and sociodemographic information. Our findings suggest that transport policies have encouraged sustainable mobility practices, particularly in the centre of Barcelona. Despite the positive results, considerable disparities exist between the inner and outer city, with a notable decline in sustainable mobility practices in the latter, due to the uneven distribution of basic services and uneven provision of public transport, together with lower density areas. Our results demonstrate that this uneven distribution reduces the available sequence profiles of inhabitants. In conclusion, the promotion of sustainable mobility policies necessitates further advances in transport, city and land-use planning that consider equity, gender, the socioeconomic profiles of citizens and mixed urban planning.

Canadian adult reference data for body composition, trabecular bone score and advanced hip analysis using DXA

DXA-derived reference data for visceral adipose tissue (VAT) and advanced hip analysis (AHA) parameters spanning the entire adult lifespan are limited. The purpose of this study was to develop age-, site- and sex-specific reference data for dual X-ray absorptiometry (DXA) -derived body composition, trabecular bone score (TBS) and advanced hip analysis (AHA) parameters across the adult lifespan. Adults (N = 908; female: 561 and male: 347) from Calgary and the surrounding area over the age of 20 years participated in this study. Participants received DXA scans of their hip (total hip [TH] and femoral neck [FN]), lumbar spine [LS], forearm [33 % site] and total body (iDXA, GE Lunar, GE Healthcare). Areal bone mineral density (aBMD, g/cm2) was captured at all sites, and body composition variables, including lean mass, fat mass and percent fat, were analyzed from the total body scan. VAT mass was assessed from total body DXA scans. Advanced hip analysis (AHA) was performed on hip scans and trabecular bone score (TBS) on the LS scans to assess bone quality. Site- and sex-specific centile curves and tables were generated using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Clinicians and researchers can use these Canadian reference data as a tool to assess body composition, TBS and AHA parameters across the adult lifespan.

CO2 foam structure and displacement dynamics in a Hele–Shaw cell

The substitution of CO2 gas with CO2 foam for improved mobility control has recently attracted research attentions in enhanced oil recovery (EOR) as well as aquifer and soil remediation. However, the interplay between CO2 foam properties and oil displacement remains less investigated. In this work, using clear visualizations, we systematically investigate the dynamic advection-dominated foam morphology, its corresponding viscosity, and the efficiency and dynamics of oil displacement process by CO2 foam in a Hele–Shaw cell under the effects of gas ratio (Rg), fluid injection rates (Qt), and surfactant type. Clear visualization enables particle image velocimetry to calculate actual, rather than nominal, foam velocity that significantly affects the estimated foam viscosity. Our results demonstrate that at elevated gas ratios under constant total injection rate, larger and more uniform bubbles with less number density and greater interfacial area are obtained. Increasing the injection rates leads to finer foam texture at a constant gas ratio. Different foam structures have an impact on the foam viscosity, with a general increasing trend of viscosity for larger bubbles as Rg increases from 0.5 to 0.85. The higher the foam viscosity, the more stable displacement interfaces with less viscous fingers are observed, leading to improved sweeping rates. The green surfactants (saponin + Cellulose NanoFibers) provide foams with higher viscosity and, thus, more stable displacement interfaces. These findings highlight the important effect of Rg–dependent foam structure on its viscosity, which in turn is crucial for controlling the mobility of CO2 foam to maximize oil recovery rate during EOR processes.

Socio-spatial inequalities in presence of primary care physicians and patients' ability to register: A simulated-patient survey in the Paris Region

ObjectivesWe studied the socio-spatial inequalities of three types of general practitioner (GP) density in the Paris metropolitan area: the density of GPs present (that is, practising) in the census block and of those registering new patients for office visits and, separately, for house calls. Study designAn exhaustive simulated patient survey enabled us to determine the number of GPs practising in the Paris metropolitan region accepting new patient registration for continuing care at their office and/or for house calls. MethodsWe measured at the level of a census block three types of GP densities: density of GPs present, density of GPs registering new patients at their office and density of GP registering new patients for house calls. We compared the association between the social deprivation level and each density measurement overall, then by stratifying for the population density of the census block. ResultsIn 2017–2018, we contacted 8171 physicians (87.6 % of the GPs in the region). Although more than 55 % of Ile-de-France census blocks had (at least) one practising GP, fewer than 40 % had one willing to register a new patient for ongoing office care, and fewer than 20 % for home care. Regardless of the GP density considered, it decreased as the census block's deprivation index rose. However, these inequalities were more marked for registration than for presence and in the most densely populated blocks. ConclusionsIn conclusion, the indicators of GPs' mere presence appear to minimise the socio-spatial disparities associated with access to registration.