Surface Mapping Research Articles

3D Uncertain Implicit Surface Mapping Using GMM and GP

3D Uncertain Implicit Surface Mapping Using GMM and GP

Anatomy of Lister's Tubercle: Implications for Volar Locked Plating of the Distal Radius.

Determining accurate intraoperative screw length in complex distal radius fractures may pose difficulties. With volar plate fixation, excessive screw length may result in extensor pollicis longus injury and this can be challenging to determine via intraoperative imaging. This study aims to identify the precise anatomic location and parameters of Lister's tubercle on the dorsal aspect of the radius. The anatomy and location of Lister's tubercle was evaluated in 26 cadaveric arms, of which 27% were female, with a mean age of 73.6 years. Additionally, Lister's tubercle was evaluated on 198 computed tomography (CT) scans using a quantitative distal radius surface map. Median age was 28 years, and 28% of the patients were female. As measured in cadaveric arms, the mean Lister's tubercle length was 12.6 mm, and width was 5.4 mm. The distance from the radial styloid to the distal and proximal border of Lister's tubercle averaged 23.0 and 10.4 mm, respectively. Of the total distal radial width, Lister's tubercle begins 43% from the radial border and spans to 42% of the ulnar border, encompassing 16% of the entire width of the dorsal distal radius. On CT mapping, the distance between the peak of Lister's tubercle and the ulnar and radial border of the radius was 46% and 54%, respectively. Female sex was associated with a smaller distal radius width, but not with a smaller Lister's tubercle. Knowledge of Lister's tubercle anatomy may assist in more precise screw placement in volar locked plating of distal radius fractures. IV-Therapeutic.

Soil Physical Properties, Root Distribution, and “Ponkan” Tangerine Yield Across Different Rootstocks in a Deep Tillage Ultisol

Deep soil tillage and proper rootstock selection mitigate the root development limitations in Ultisol’s Bt horizon, enhancing the citrus yield potential. This study evaluates the root spatial distribution of three Ponkan tangerine rootstocks in Ultisol under deep tillage alongside the physical-hydric attributes and plant measurements. The experimental area underwent furrow creation, subsoiling, and hole opening for planting. The treatments included three rootstocks: “Cravo Santa Cruz” (CSC), “Sunki Tropical” (ST), and “Citrandarin Índio” (CI). Under the Ultisol preparation, these rootstocks were compared to a native forest area (FA). Three years post-initial tillage, soil samples were collected at depths of 0–0.05, 0.35–0.40, and 0.45–0.50 m from the pre-established positions. The evaluation encompassed soil dispersive clay, available water, crop water use, plant measurement, and crop yield. The root evaluation utilized the crop profile method and 2D images, with subsequent surface mapping of the root variables, number (NR), and diameter (RD) analyzed via kriging geostatistical analysis. The Ultisol showed significant changes in its physical-hydric attributes regarding structural change and more excellent clay dispersion, with a considerable contribution to the micropore volume. Deep tillage effectively improved the root spatial distribution, especially concerning the number and diameter of roots, and enhanced the water use, reflected in the vegetative growth and yield, with the rootstock CSC standing out.

The Synthesis and Application of Chitosan@Ag2O@Mn3O4 Three‐Phase Nanocomposite as a Heterogeneous Catalyst in the Synthesis of 2‐Hydroxynaphthalenepyrimidine Trione

ABSTRACTThe catalyst is often the most expensive element in a chemical process, rather than the reactants or products. Apart from the financial benefits, it is equally crucial to recover and reuse the catalyst to prevent waste and enhance the process's greenness. This study successfully synthesized the new, superior, and recyclable heterogeneous chitosan@Ag2O@Mn3O4 three‐phase nanocatalyst with high surface area and stability using Ag2O and Mn3O4 nanoparticles that stabilized on chitosan by copreparation method and was characterized by Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), transmission electron microscopy (TEM), surface mapping (mapping), X‐ray diffraction (XRD), Brunner–Emmett–Teller (BET), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques in detail. Following, the efficiency of the synthesized nanocatalyst in the preparation of 2‐hydroxynaphthalenepyrimidine triones using the reaction of aromatic aldehydes, β‐naphthol, and barbituric acid derivatives was investigated and proved. The advantages of this method include performing reactions at room temperature, green media, short reaction times, and the easy purification of the products.

The Cibarco anticline of the northernmost San Jacinto fold belt: Possible influence of mud diapirism on the Neogene to the recent evolution of the structure where the first oil and gas wells were drilled in Colombia

The Cibarco anticline, located in the northwestern South American convergent margin, is a long (approximately 40 km) and narrow (2.5 km wide), south-southwest–north-northeast-trending structure that separates two much wider depocenters, the Tubará-Juan de Acosta depocenter (approximately 20 km wide) to the west, and the Sabanalarga syncline (approximately 11 km wide) to the east. Detailed geologic surface mapping and subsurface seismic interpretation suggest that the formation and evolution of the Cibarco anticline have been strongly influenced by mud diapirism, which has been focused along a west-southwest–east-northeast-trending, inverted pre-Oligocene extensional fault. Seismic interpretation and outcrop analyses also confirmed that the source of mobile shales is the Upper Oligocene marlstones of the Lower Ciénaga de Oro Formation. We suggest that the main mechanism that caused the overpressures that triggered and controlled shale mobilization was disequilibrium compaction related to the sedimentary loading of impermeable seals and the shortening and inversion of pre-Oligocene extensional faults. Growth strata indicate that the Upper Oligocene mud started moving in Early Miocene times during the deposition of the thick Porquero mudstones, and it stopped migrating in Latest Miocene times. After an uplift and erosion event, mud diapirism remained inactive in the Early Miocene, and it was then reactivated in Late Pliocene times. Slight mud migration focused on the inverted fault continued throughout the Pleistocene and to the present. Today, the slight mud migration to the surface is observed in volcanoes located in the northern strand of the Cibarco anticline, although the rest of the anticline has become welded. Our new interpretations, carried out more than a century after the first hydrocarbon exploration activities began in Colombia, will hopefully allow us to increase our understanding of shale tectonics, petroleum systems, and plays in this portion of the convergent margin.

Asynchronous Visual-Inertial Odometry for Event Cameras

Abstract. Event cameras are bio-inspired visual sensors that output changes in pixel-level brightness asynchronously instead of standard intensity frames at a fixed rate. These cameras offer reliable visual information in high-speed motion and high dynamic range (HDR) scenes, addressing the limitations of traditional cameras in such scenarios. Therefore, research of integrating event cameras into established visual algorithms holds significant value. In this study, based on traditional Visual-Inertial Odometry (VIO) frameworks, we proposed an innovative asynchronous monocular event-based inertial odometry method to fully exploit the benefits of event cameras. First, the corner features are extracted separately from the raw event stream and the time surface map, followed by uniform feature selection to accurately describe three-dimensional spatial geometry. Then, feature tracking is achieved by integrating these two event representation methods. In addition, our method obtains stable and high frequency state estimation by fusing event and IMU measurements through graph optimization. We validate the effectiveness of our proposed approach, comparing with several state-of-the-art EVIO systems and VIO systems.

High dynamic range land wavefield reconstruction from randomized acquisition

Compressive sensing (CS) is an alternative to regular Shannon sampling that captures similar information from reduced measurements. It relies on randomized sampling patterns and a sparse data representation to reconstruct the regularly sampled object. CS is an important ingredient in affordable seismic acquisition, which can lead to improvements in the near-surface mapping and noise suppression for land data. However, the near surface traps most of the source-generated energy, resulting in data that are rich in high-wavenumber content and have amplitudes spanning several orders of magnitude. When dealing with such high dynamic range nonstationary data, the Fourier domain is not optimal for providing a sparse representation — a necessary condition for successful application of CS. In contrast, a discrete complex wavelet transform can localize high-energy features, has good directional selectivity, and is near-shift invariant. Combined, these properties allow complex wavelets to represent detail-rich wavefields in a compact form. To leverage these features and achieve good CS reconstructions, we develop a scale- and orientation-dependent iterative soft thresholding (IST) scheme for reconstructing high dynamic range wavefields. Our approach requires little parameterization, is easy to implement, and is robust to reconstructed wavefield sampling grid and dynamic range. We test IST on different wavefields with randomly missing traces and compare the data reconstructions with the spectral projected gradient solver and projection onto convex sets. We quantify the reconstructions by a direct comparison of Fourier coefficients between fully sampled and reconstructed wavefields. Taking log10 of Fourier coefficients prior to computing the quality metric deemphasizes the importance of magnitude match while highlighting Fourier coefficient support accuracy, which usually translates into good structural fidelity of reconstructed data. We find that IST performs consistently among all examples, yielding good phase match while performing gentle denoising.

Introducing a New Index for Flood Mapping Using Sentinel-2 Imagery (SFMI)

Accurate surface water detection and mapping using Remote Sensing (RS) imagery is crucial for effective water and flood management and for supporting natural ecosystems and human development. In recent years, RS technology and satellite image processing have significantly advanced in flood and permanent water extraction, particularly in water index, clustering, classification, and sub-pixel analysis. Water-index-based techniques, distinguished by their quickness and convenience, offer notable advantages. The dynamic and extensive nature of surface water and flooded areas make the water index particularly effective for monitoring large areas. However, challenges arise due to the complexity of ground surfaces in aquatic environments, including shadows in built-up, vegetated, and mountainous regions, narrow water bodies, and muddy water. This research presents a new Flood Mapping Index using Sentinel-2 imagery (SFMI) designed to address these challenges and identify water and flooded areas more accurately. The SFMI utilizes visible and near-infrared bands derived from Sentinel-2 data, employing 10-meter bands to compensate for errors arising from spectral and spatial changes more effectively. The SFMI index is designed based on the spectral signatures of various land cover classes, utilizing the potential of 10-meter resolution bands to identify water bodies and flood areas. Unlike the most conventional methods, the SFMI identifies and extracts water and flood regions without complex thresholding, and thus mitigates the impact of irrelevant features, such as dense vegetation and rugged topography on the flood and water body maps. The proposed index was tested in two large areas with high spectral diversity, yielding promising results. The SFMI index demonstrates an average overall accuracy of 97.1% for pre-flood water extraction, 97.95% for post-flood water extraction, and 98% for flooded area extraction. Moreover, the results showed an average kappa coefficient of 0.958 for pre-flood water extraction, 0.965 for post-flood water extraction, and 0.978 for flooded area extraction. The performance of the SFMI index for extracting flooded areas (ΔSFMI) is superior to its performance for water extraction both before and after the flood. However, it is essential to note that the accuracy of the flooded area map is contingent on the accuracy of the water area map both before and after the flood. Thus, the SFMI index based on 10-meter Sentinel-2 imagery accurately detects floods and water bodies over time, without relying on thresholding, making it suitable for flood management and monitoring various water bodies like dams, lakes, wetlands, and rivers. The findings underscore the applicability of the proposed SFMI index in diverse and spectrally rich areas, demonstrating its effectiveness in monitoring various surface water bodies, detecting floods, and managing flood crises.

Force and Energy Transmission at the Brain-Skull Interface of the Minipig In Vivo and Post-Mortem

The brain-skull interface plays an important role in the mechano-pathology of traumatic brain injury (TBI). A comprehensive understanding of the mechanical behavior of the brain-skull interface in vivo is significant for understanding the mechanisms of TBI and creating accurate computational models. Here we investigate the force and energy transmission at the minipig brain-skull interface by non-invasive methods in the live (in vivo) and dead animal (in situ). Displacement fields in the brain and skull were measured in four female minipigs by magnetic resonance elastography (MRE), and the relative displacements between the brain and skull were estimated. Surface maps of deviatoric stress, the apparent mechanical properties of the brain-skull interface, and the net energy flux were generated for each animal when alive and at specific times post-mortem. After death, these maps reveal increases in relative motion between brain and skull, brain surface stress, stiffness of brain-skull interface, and net energy flux from skull to brain. These results illustrate the ability to study both skull and brain mechanics by MRE; the observed post-mortem decrease in the protective capability of the brain-skull interface emphasizes the importance of measuring its behavior in vivo.

Novel schiff base as potent antimalarial: Synthesis, single crystal x-ray structure, spectroscopic analysis, theoretical investigation and molecular docking studies

The title compound N’-[(E)-(2-Hydroxy-1-naphthyl)methylene]benzohydrazide was compounded completely by the condensation reaction between 2-hydroxynaphthaldehyde and benzhydrazide. The Schiff base obtained was attributed by single-crystal X-ray diffraction (SCXRD), FT-IR, UV–Visible spectroscopy, and mass spectrometry. Computational validation was performed using DFT- B3LYP/6–311 + G(d,p) theory to ascertain the optimal geometry of the compound. Thermodynamic parameters and nonlinear optical (NLO) plots were also investigated. The HOMO-LUMO energy gap was found to be 3.6380 eV. Mulliken charges were found and electrostatic field surface mapping conducted to explore various properties. Theoretical findings were consistent with experimental results. Molecular docking studies revealed that the Schiff base exhibits antimalarial activity against Plasmodium falciparum, with the LibDock score and binding energy assessed for the malaria-causing protein 4WZ3. ADMET analysis indicated favorable pharmacokinetic properties of the synthesized ligand compared to current antimalarial drugs, highlighting its potential for malaria treatment.

Synthesis, spectroscopy, solvation effect, topology and molecular docking studies on 2,2′-((1,2 phenylenebis (azaneylylidene)) bis (methaneylylidene)) bis(4-bromophenol)

The 2,2′-((1,2 phenylenebis (azaneylylidene)) bis (methaneylylidene)) bis(4-bromophenol) (5BSOP) Schiff base was synthesized, characterized using different spectroscopic techniques, and the data are compared with predictions from DFT computations. The calculated energy values are -8.65 eV (HOMO) and -6.66 eV (LUMO), and the energy gap was found to be 1.99 eV. The reactive atom sites in the chemical are identified by MEP analysis. The locations of localized and delocalized orbitals are revealed through ELF and LOL surface maps. The sites of non-covalent interactions are exposed by RDG and NCI analysis. The possible inter and intra-molecular interactions were determined by NBO analysis and the highest stabilization energy observed was 40.07 kcal/mol. Biological performance as a HMGCS2 expression enhancer was predicted by Pass online studies. Molecular docking simulation with protein 706I having HMGCS2 expression inhibition characteristics revealed a stable receptor-ligand interaction pose at a binding energy of -4.74 kcal/mol. The interaction of the Phe61 amino acid chain of 706I with 5BSOP through conventional H-bond expressed a bond distance of 3.24 A°.

DFT, Structure Activity Relationship, Fukui, Wave Function, NBO, NLO, Spectral and Hole-Electron Analyses of Dexmethylphenidate

Dexmethylphenidate (DMP) is used to treat attention deficit hyperactivity disorder (ADHD) and belongs to the central nervous system (CNS) stimulant group of medicines. The physical properties of DMP were analyzed under the DFT/B3LYP/6-311++G(d,p) basis set. The ESP study reveals the electrophilic attack is possible, while FMO analysis shows that the molecule is hard, stable and an electron donor. The non-covalent interaction (NCI) study explains that van der Waals and steric repulsion forces are observed. The HEI studies indicated that this molecule has CT excitation in the S0→S5 state. The shaded surface map analysis reveals the presence of electron depletion regions in this molecule. The UV-Vis spectral analysis was carried out in various solvents. The Fukui function analysis conveys that 7C is the best domain for electrophilic attack. Theoretical IR determinations and NLO properties were also performed. The structure-activity relationship findings were performed in order to improve the docking score.

Effects of stamp material and restoration depth on the accuracy of direct composite resin restorations using stamp technique

ObjectivesTo evaluate the effects of different stamp materials and restoration depths on the accuracy of direct composite resin restorations using stamp technique. MethodsEighty standard resin teeth were divided into four groups based on different stamp materials: flowable composite resin (FR), vinyl polydimethyl siloxane (VPS) for bite registration (VB), VPS for impression (VI) and transparent VPS (TV). Each material group was further divided into two subgroups based on restoration depth (1 and 2 mm; n = 10). Standardized Class I cavities were prepared and restored with the corresponding stamps. Pre- and post-treatment scans of each tooth were fitted using Geomagic Control X software, generating deviation distribution maps of the occlusal surface. The accuracy indicators, including mean height variation (MHV), root mean square (RMS), and proportions of height variation with different ranges (PHVrange), were recorded to evaluate the accuracy of restorations. Analysis of variance (ANOVA) were used for statistical analysis (α=0.05). ResultsThe type of stamp material significantly affected all accuracy indicators, while restoration depth did not show a significant effect on any of the indicators. MHV values ranged from 29.70 ± 5.88 μm to 63.52 ± 9.58 μm, and RMS values ranged from 62.78 ± 8.76 μm to 101.79 ± 13.17 μm, displaying a trend of FR<VB<VI<TV. The FR groups had the highest PHV<0.05mm values (72.24 ± 3.40 % for 1 mm, 71.47 ± 8.54 % for 2 mm) and the lowest PHV>0.2mm values (0.70 ± 0.50 % for 1 mm, 0.94 ± 0.47 % for 2 mm). In contrast, the TV groups exhibited the lowest PHV<0.05mm values (59.69 ± 10.23 % for 1 mm, 59.67 ± 5.70 % for 2 mm), while the VI groups showed the highest PHV>0.2mm values (7.34 ± 1.58 % for 1 mm, 8.20 ± 3.16 % for 2 mm). ConclusionsThe accuracy of direct composite resin restorations using stamp made of flowable composite resin was higher than that of all tested VPS materials, thereby reducing the need for occlusal adjustment and improving clinical efficiency. Besides, restoration depth had no significant impact on the accuracy of stamp technique, regardless of the stamp material used. Clinical significanceThe accuracy of direct composite resin restorations using stamp technique with different stamp materials varies. The flowable composite resin stamp exhibits higher accuracy compared with VPS stamps, reducing the need for occlusal adjustments.

Research into the Structure and Adhesion of WCCoCr Coatings Plasma-Sprayed onto Castings of AlSi Alloy Plates

The article presents structural investigations and mechanical properties of hard coatings deposited by spraying WCCoCr powder in an argon-hydrogen plasma jet onto the surfaces of AlSi10Mg alloy casting plates. Two variants (A and B) of processing parameters of the powder spraying process onto the surface of silumin plates were applied, resulting in different coating thickness. The coating applied according to variant A was done with 12 passes, and its thickness was approximately 150 μm. The coating applied according to variant B was done with 20 passes, and its thickness was about 320 μm. The microstructures of these coatings are similar, consisting of wavy, alternately deposited phases of solid solutions with varying concentrations of elements, and fine spherical phases, irregularly dispersed carbides. A qualitative analysis of the distribution of microstructure components was performed based on surface mapping. Precipitates differing in their degree of grayness and shape were identified based on microanalysis of their chemical composition. The porosity assessment of coatings performed in five randomly selected areas amounts to an average of 9%. The applied coatings exhibit good adhesion to the substrate, as evidenced by the absence of delamination during scratching tests using a diamond Rockwell indenter loaded with a force of 10 N. The coating hardness averaged 1180HV0.2. The test results indicate the high quality of the WCCoCr coatings, regardless of their thickness.

Neural network reconstruction of the left atrium using sparse catheter paths.

Catheter-based radiofrequency ablation for pulmonary vein isolation has become the first line of treatment for atrial fibrillation in recent years. This requires a rather accurate map of the left atrial sub-endocardial surface including the ostia of the pulmonary veins, which requires dense sampling of the surface and currently takes more than 10min. The focus of this work is to provide left atrial visualization early in the procedure to ease procedure complexity and enable further workflows, such as using catheters that have difficulty sampling the surface. We propose a dense encoder-decoder network with a novel regularization term to reconstruct the shape of the left atrium from partial data which is derived from simple catheter maneuvers. To train the network, we acquire a large dataset of 3D atria shapes and generate corresponding catheter trajectories, from which traversed point clouds are obtained. Once trained, we show that the suggested network can sufficiently approximate the atrium shape based on a given trajectory. We compare several network solutions for the 3D atrium reconstruction. We demonstrate that the solution proposed produces realistic visualization using partial acquisition within a 3-min time interval using human clinical cases.

Global Localization using OpenStreetMap and Elevation Offsets

Localization is a critical component in autonomous vehicle navigation stacks. While GNSS-only localization cannot be fully reliable and available all the time, localization based on 3D high-definition (HD) maps have to be robust to world changes, which is still a challenging issue. Added to that, in general, HD maps are expensive and difficult to construct and maintain.In this paper, we propose a particle filter-based 2D global pose estimation method that can use the crowdsourced OpenStreetMap (OSM) API, a digital surface map, or both. The main contributions of the proposed approach are: that it is lightweight, does not require the vehicle to map the environment, does not require a GPU (can be used with low-power computing resources), is agnostic to the odometry source, and achieved relatively low position and orientation errors for this localization modality using the KITTI dataset sequences. The proposed method's implementation is open source and is available with the experimental results on our GitHub page.

3256: Surface Mapping with Machine Learning for Resimulation Decision Support in Prostate Proton Therapy

3256: Surface Mapping with Machine Learning for Resimulation Decision Support in Prostate Proton Therapy

Enhancing SLAM efficiency: a comparative analysis of B-spline surface mapping and grid-based approaches

Enhancing SLAM efficiency: a comparative analysis of B-spline surface mapping and grid-based approaches

Resistivity as a Witness of Local Crystal Growth Conditions

A detailed knowledge of the growth front geometry during physical vapor transport (PVT) growth of SiC single crystals is beneficial to achieve high quality n+ SiC substrates for power device applications. In this report we show how mapping of resistivity in SiC wafers can shed light on local growth conditions, which are very difficult-to-study in situ. We consider both thermodynamic quantities (absolute temperature T and partial pressure pN₂) and geometric characteristics of the growth surface relevant to growth kinetic parameters, namely atomic terrace width and atomic step velocity. Specifically, we show how an elevation map of the growth surface can be reconstructed from a spatially-resolved measurement of resistivity in a SiC wafer by integrating the spatial derivative of elevation with respect to the basal plane, which is assumed to be related to local resistivity through dependence of non-equilibrium nitrogen incorporation on the atomic step velocity.

Force-Free Identification of Minimum-Energy Pathways and Transition States for Stochastic Electronic Structure Theories.

The accurate mapping of potential energy surfaces (PESs) is crucial to our understanding of the numerous physical and chemical processes mediated by atomic rearrangements, such as conformational changes and chemical reactions, and the thermodynamic and kinetic feasibility of these processes. Stochastic electronic structure theories, e.g., Quantum Monte Carlo (QMC) methods, enable highly accurate total energy calculations that in principle can be used to construct the PES. However, their stochastic nature poses a challenge to the computation and use of forces and Hessians, which are typically required in algorithms for minimum-energy pathway (MEP) and transition state (TS) identification, such as the nudged elastic band (NEB) algorithm and its climbing image formulation. Here, we present strategies that utilize the surrogate Hessian line-search method, previously developed for QMC structural optimization, to efficiently identify MEP and TS structures without requiring force calculations at the level of the stochastic electronic structure theory. By modifying the surrogate Hessian algorithm to operate in path-orthogonal subspaces and at saddle points, we show that it is possible to identify MEPs and TSs by using a force-free QMC approach. We demonstrate these strategies via two examples, the inversion of the ammonia (NH3) molecule and the nucleophilic substitution (SN2) reaction F- + CH3F → FCH3 + F-. We validate our results using Density Functional Theory (DFT)- and Coupled Cluster (CCSD, CCSD(T))-based NEB calculations. We then introduce a hybrid DFT-QMC approach to compute thermodynamic and kinetic quantities, free energy differences, rate constants, and equilibrium constants that incorporates stochastically optimized structures and their energies, and show that this scheme improves upon DFT accuracy. Our methods generalize straightforwardly to other systems and other high-accuracy theories that similarly face challenges computing energy gradients, paving the way for highly accurate PES mapping, transition state determination, and thermodynamic and kinetic calculations at significantly reduced computational expense.