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Moving contact line dynamics calculations include two models: precursor film models and slip models. The lubrication approximation method is used to establish a three-dimensional mathematical model to analyze the droplet thermocapillary migration behavior on a non-uniformly heated solid substrate with a wettability track. The contact line dynamics in the slip model and the disjoining pressure effect in the precursor model are proposed to regulate the substrate wettability. Both models are numerically implemented to investigate droplet spreading for three cases: free spreading on an isothermal substrate, thermocapillary migration on a uniform wettability substrate, and thermocapillary migration on a wettability-confined track. For the case of free spreading on an isothermal substrate, the three-dimensional results of the slip and precursor contact line models are essentially consistent with two-dimensional slip model results. For the case of thermocapillary migration on a uniform wettability substrate, the results of the two models essentially agree with the experimental results. Decreasing the thermal gradient reduces the discrepancies between the two models that result from the coordinate transformation method used in the slip model, which reduces the contact angles measured in the y-direction and enlarges the advancing contact angle in the migration direction. For the case of thermocapillary migration on a wettability-confined track, the slip model gradually shows a "dynamic-pinning" behavior with increasing equilibrium contact angle in the hydrophobic region. By contrast, the precursor film model maintains a stationary pinning behavior but separates a residual liquid outside the track. The precursor film model is preferred over the slip model in lubrication approximations for three-dimensional fluids when calculating complex moving contact dynamics caused by wettability differences. However, the precursor film model must be further optimized to prevent numerical instability. [ABSTRACT FROM AUTHOR]

To enhance the performance of solid oxide electrolysis cell (SOEC), two biomimetic flow fields are designed based on the vein structures of ginkgo and clover leaves in this study. A three-dimensional SOEC model is developed to investigate the impacts of the flow fields on the electrochemical performance of SOEC. The results indicate that the SOEC with biomimetic leaf-like flow fields require lower voltage compared to the SOEC with conventional serpentine and parallel flow fields. Under the same simulation conditions, the voltage demand of the SOEC with the clover flow field was found to be 0.1154 V lower than that of the SOEC with the serpentine flow field. To better understand the reasons behind this improvement, the distribution of pressure, reaction gas, chemical reaction, overpotential, and temperature are analyzed. The findings demonstrate a significant improvement in temperature uniformity in the cell with the clover flow field, showing a 70.73% enhancement compared to the cell with the serpentine flow field. The utilization of these biomimetic flow fields has the potential to improve the performance and stability of SOEC operation. • Two biomimetic flow fields inspired by ginkgo and clover leaves are proposed. • A three-dimensional model is established to study the impacts of flow fields. • The voltage demand reduction can reach 0.115 V by using a bio-inspired flow field. • The uniformity of temperature increased by 70.73% in a bio-inspired flow field. [ABSTRACT FROM AUTHOR]

Harnessing non-spatial properties of photons as if they represent an additional independent coordinate underpins the emerging synthetic dimension approach. It enables probing of higher-dimensional physical models within low-dimensional devices, such as on a planar chip where this method is relatively nascent. We demonstrate an integrated thin-film lithium niobate ring resonator that, under dynamic modulation, simulates a tight-binding model with its discrete frequency modes representing lattice sites. Inter-mode coupling, and the simulated lattice geometry, can be reconfigured by controlling the modulating signals. Up to a quasi-3D lattice connectivity with controllable gauge potentials has been achieved by simultaneous synchronized nearest-, second- and third-nearest-neighbor coupling, and verified by acquiring synthetic band structures. Development of synthetic frequency dimension devices in the thin-film lithium niobate photonic integration platform is a key step in increasing the complexity of topological models achievable on a chip, combining efficient electro-optic mode coupling with non-linear effects for long-range mode interactions. Lithium niobate on insulator (LNOI) is emerging as a powerful photonic integration platform for synthetic dimension approaches that enable probing of higher-dimensional physical models within low-dimensional devices. The authors present a LNOI ring device, whose frequency modes represent lattice sites for versatile simulation of tight-binding models with up to three-dimensional connectivity. [ABSTRACT FROM AUTHOR]

Daily agro-industrial waste, primarily cellulose, lignin, and hemicellulose, poses a significant environmental challenge. Harnessing lignocellulolytic enzymes, particularly endo-1,4-β-xylanases, for efficient saccharification is a cost-effective strategy, transforming biomass into high-value products. This study focuses on the cloning, expression, site-directed mutagenesis, purification, three-dimensional modeling, and characterization of the recombinant endo-1,4-β-xylanase (XlnA) from Aspergillus clavatus in Escherichia coli. This work includes evaluation of the stability at varied NaCl concentrations, determining kinetic constants, and presenting the heterologous expression of XlnAΔ36 using pET22b(+). The expression led to purified enzymes with robust stability across diverse pH levels, exceptional thermostability at 50 °C, and 96–100% relative stability after 24 h in 3.0 M NaCl. Three-dimensional modeling reveals a GH11 architecture with catalytic residues Glu 132 and 22. XlnAΔ36 demonstrates outstanding kinetic parameters compared to other endo-1,4-β-xylanases, indicating its potential for industrial enzymatic cocktails, enhancing saccharification. Moreover, its ability to yield high-value compounds, such as sugars, suggests a promising and ecologically positive alternative for the food and biotechnology industries. [ABSTRACT FROM AUTHOR]

The French National Radioactive Waste Management Agency is leading the design of a deep geological radioactive waste disposal to be located in the Callovo-Oxfordian formation. At the disposal main level, large-diameter galleries will ensure access to the storage cells and connection between zones. After a long operational period, the disposal will be closed by sealing structures located at some key positions to ensure post-closure safety over the long term. The seals are intended to prevent the flow of water and the migration of radionuclides from the disposal to the biosphere throughout the entire storage life. Thus, the long-term safety of the disposal relies to a large extent on the performance of these structures. The paper presents the work carried out to assess and simulate the phenomena underlying the response and performance of a large-diameter sealing concept under real disposal conditions. The complexity of the problem is addressed by considering in the simulations large-scale 3D geometries, advanced constitutive models, complex coupled phenomena, key geometric details at decimetre scale, and all the phases from the excavation to the post-closure period (~ a few thousand years). Highlights: The three-dimensional hydro-mechanical modelling of a large structure concept, foreseen to seal access galleries in a clayey rock deep disposal, has been carried out. Model considers large geometry (order of tens of meters), anisotropy, constitutive laws of different complexity, interfaces, and relevant geometrical details (order of cm). Results evidence a progressive hydration and swelling of the sealing core during more or less 2000 years after disposal closure. The concrete plugs placed at both ends of the sealing structure move longitudinally, but core density and swelling pressure do not change significantly in seal central part. Swelling core recompresses partially the excavation-induced damaged zone in the area of lining deposition. [ABSTRACT FROM AUTHOR]

This study is part of numerical simulations performed on an in-situ heating test conducted by the French National Radioactive Waste Management Agency (Andra) at the Meuse/Haute-Marne Underground Research Laboratory (URL) to study the thermo-hydromechanical behavior of the host Callovo-Oxfordian COx claystone in quasi real conditions, through the international research project DECOVALEX. We present a numerical study of damage and cracking process in saturated claystone subjected to thermo-hydromechanical coupling by considering material heterogeneity distribution. For this purpose, a macroscopic elastic model is first determined by using two steps of homogenization by taking into account the effects of porosity and mineral inclusions. This model is implemented into a finite element code devoted to solving thermo-hydromechanical coupling problems. The nucleation and propagation of cracks are described by using an extended phase-field method, considering the effects of temperature and fluid pressure on the evolution of phase-field. The proposed model is applied to the numerical analysis of cracking process due to excavation and heating around a group of boreholes (CRQ). The numerical results of the 3D simulation are compared with in-situ measurements of temperature and pore pressure distribution. The excavation damage zone and heating fracture is reproduced and analysed according to the structure of the heating position and the heterogeneity of the rock. Highlights: A phase-field model is developed with thermo-hydromechanical processes; Both tensile and shear cracks are taken into account; Crack nucleation is emphasized by spatial heterogeneity of material properties; Cracking processes due to thermal-hydraulic interaction are analyzed in three-dimensional conditions. [ABSTRACT FROM AUTHOR]

The thermal conductivity of frozen soil is a significant parameter in theoretical research and practice pertaining to surface environments and geothermal energy. This paper proposes a three-dimensional random model that improves the accuracy of predicting thermal conductivity in unsaturated frozen soil, thereby reducing the difficulty in determining its thermal parameters. To achieve this, a nuclear magnetic resonance (NMR) analyzer was used to determine the proportion of the four phases and the pore distribution of unsaturated frozen soil. A portable thermal property analyzer was also used to measure the thermal conductivity of frozen soil and assess the relationship between unfrozen moisture content and thermal conductivity. Using MATLAB, a three-dimensional stochastic porous medium model of unsaturated frozen soil was developed and then loaded into COMSOL simulation software, after which the pore ratios from the NMR results were inputted, and the steady-state solid heat transfer module automatically calculated the thermal conductivity of the simulation model. The calculated value was compared with experimental data, and the effectiveness and simulation accuracy of the model were analyzed. The study demonstrated that unfrozen water significantly affects the thermal conductivity of frozen soil, and pore water always maintains dynamic equilibrium with ice. Furthermore, the thermal conductivity of soils increases with decreasing temperature, increasing moisture content, or increasing unfrozen moisture content. The calculated value of the simulation model and measured value of the test exhibited the same change trend, and the fitting effect was excellent, validating the reliability of the model. Thus, the results of this study provide valuable reference material for future developments related to soil thermodynamics and temperature prediction. [ABSTRACT FROM AUTHOR]

Secondary cooling electromagnetic stirring (S-EMS) significantly impacts the internal quality of continuous casting slabs. In order to investigate the effects of S-EMS modes on segregation in slabs, a three-dimensional numerical model of the full-scale flow field, solidification, and mass transfer was established. A comparative analysis was conducted between continuous electromagnetic stirring and alternate stirring modes regarding their impacts on steel flow, solidification, and carbon segregation. The results indicated that adopting the alternate stirring mode was more advantageous for achieving uniform flow fields and reducing the disparity in solidification endpoints, thus mitigating carbon segregation. Specifically, the central carbon segregation index under continuous stirring at 320 A was 1.236, with an average of 1.247, while under alternate stirring, the central carbon segregation index decreased to 1.222 with an average of 1.227. [ABSTRACT FROM AUTHOR]

Buildings are significant components of digital cities, and their precise extraction is essential for the three-dimensional modeling of cities. However, it is difficult to accurately extract building features effectively in complex scenes, especially where trees and buildings are tightly adhered. This paper proposes a highly accurate building point cloud extraction method based solely on the geometric information of points in two stages. The coarsely extracted building point cloud in the first stage is iteratively refined with the help of mask polygons and the region growing algorithm in the second stage. To enhance accuracy, this paper combines the Alpha Shape algorithm with the neighborhood expansion method to generate mask polygons, which help fill in missing boundary points caused by the region growing algorithm. In addition, this paper performs mask extraction on the original points rather than non-ground points to solve the problem of incorrect identification of facade points near the ground using the cloth simulation filtering algorithm. The proposed method has shown excellent extraction accuracy on the Urban-LiDAR and Vaihingen datasets. Specifically, the proposed method outperforms the PointNet network by 20.73% in precision for roof extraction of the Vaihingen dataset and achieves comparable performance with the state-of-the-art HDL-JME-GGO network. Additionally, the proposed method demonstrated high accuracy in extracting building points, even in scenes where buildings were closely adjacent to trees. [ABSTRACT FROM AUTHOR]

Glutathione-S-transferase enzymes (GSTs) are essential components of the phase II detoxification system and protect organisms from oxidative stress induced by xenobiotics and harmful toxins such as 1-chloro-2,4-dinitrobenzene (CDNB). In Tetrahymena thermophila, the TtGSTm34 gene was previously reported to be one of the most responsive GST genes to CDNB treatment (LD50 = 0.079 mM). This study aimed to determine the kinetic features of recombinantly expressed and purified TtGSTm34 with CDNB and glutathione (GSH). TtGSTm34-8xHis was recombinantly produced in T. thermophila as a 25-kDa protein after the cloning of the 660-bp full-length ORF of TtGSTm34 into the pIGF-1 vector. A three-dimensional model of the TtGSTm34 protein constructed by the AlphaFold and PyMOL programs confirmed that it has structurally conserved and folded GST domains. The recombinant production of TtGSTm34-8xHis was confirmed by SDS‒PAGE and Western blot analysis. A dual-affinity chromatography strategy helped to purify TtGSTm34-8xHis approximately 3166-fold. The purified recombinant TtGSTm34-8xHis exhibited significantly high enzyme activity with CDNB (190 µmol/min/mg) as substrate. Enzyme kinetic analysis revealed Km values of 0.68 mM with GSH and 0.40 mM with CDNB as substrates, confirming its expected high affinity for CDNB. The optimum pH and temperature were determined to be 7.0 and 25 °C, respectively. Ethacrynic acid inhibited fully TtGSTm34-8xHis enzyme activity. These results imply that TtGSTm34 of T. thermophila plays a major role in the detoxification of xenobiotics, such as CDNB, as a first line of defense in aquatic protists against oxidative damage. [ABSTRACT FROM AUTHOR]

In this paper, we mainly study the dynamic properties of a class of three-dimensional SIR models. First, we use the complete discriminant theory of polynomials to obtain the parameter conditions for the topological types of each fixed point. Second, by employing the centre manifold theorem and bifurcation theory, we prove that the system may undergo transcritical, flip and Neimark–Sacker bifurcations at fixed points. Finally, we simulated all the codimension-1 bifurcations. We found that the system also has codimension-2 bifurcations, i.e. 1:2, 1:3 and 1:4 strong resonances. [ABSTRACT FROM AUTHOR]

Recognizing the variety of borders that gather and divide our world, such as geographical, temporal, social and psychological, the study highlights that the transit across these borders drives changes and continuities that contribute to human development. The research emphasizes the relevance of reviewing both the individual singularities and the shared aspects of border crossing experiences. The matching of these approaches allows building theoretical models referring to those experiences. Thus, this article aims to review borders crossing as a developmental and abductively generalizable process. Through the analogy between Abductive Generalization and photogrammetry, the study proposes an innovative way of representing these complex experiences. Three ways of border crossing - spatial displacement, imagination and social interactions - are explored in terms of their developmental potential. Using a case study of psychologists in a humanitarian non-governmental organization - NGO, an abductively generalized model is presented highlighting the spatial, cultural and psychological dimensions involved. In addition, the study proposes a three-dimensional helical model of development inspired by photogrammetry, incorporating principles of this technique to improve the understanding on the border crossing process. By recognizing mesogenetic influences, such as institutional and cultural dimensions, the article puts forward an interdisciplinary approach to understand development through border crossing. The models presented may potentially drive future research and interventions in Semiotic Cultural Psychology, enriching the promotion of human development in different border contexts. The study fosters the extension of this work by including several perspectives, methods and paradigms. [ABSTRACT FROM AUTHOR]

This study intends to theoretically analyze the effects of different shapes of corrugated electrolytes on cell performance. On the basis of the mesoscale electrode–electrolyte interface modification theory, corrugated electrolytes with different shapes are applied to conventional anode-supported planar solid oxide fuel cells (SOFCs). Three-dimensional models of solid oxide fuel cells with electrolytes corrugated in different shapes were developed. For the purpose of further understanding the influence mechanism of the corrugated electrolyte on the cell, we analyze the influence of the corrugated electrolyte on the overall performance of the cell. Furthermore, the local gas distribution, concentration polarization, activation polarization, exchange current density and electron current density are discussed. Results indicate that the corrugated electrolyte structure reduces the local exchange current density, while the extension of the activation reaction zone results in an increase in the overall charge transfer, which leads to the improvement of cell performance. And for different corrugated shapes, the area expansion degree of corrugated electrolyte is proportional to the degree of cell performance improvement. Under the operating voltage of 0.7 V, the average current density improvement percentage of the rectangular corrugated electrolyte with a spreading factor of 1.47 is 38.01%. [ABSTRACT FROM AUTHOR]

Cavities are common subsurface anomalies that have a significant impact on the bearing capacity of footings. While cavities behave three-dimensionally, in previous studies, the analysis of cavities has been limited to two-dimensional plane-strain analysis because of the time-consuming nature and complexity of three-dimensional modeling. However, this study demonstrates that the bearing capacity factor derived from three-dimensional modeling can be up to 10 times higher than that obtained from plane-strain analysis, highlighting the importance of considering three-dimensional effects. The present paper conducted three-dimensional simulations to investigate the impact of spherical cavity on the failure mechanisms and bearing capacity of footings under undrained conditions. An extensive parametric study was performed to investigate the influential parameters, including footing width to cavity dimension ratio (B/D), cover depth ratio (C/D), overburden factor (γD/Su), and void eccentricity ratio (S/D) for both circular or square footings. The results indicate that increasing the overburden factor and void eccentricity ratio leads to a decrease and increase in the bearing capacity of the footing, respectively. Furthermore, changes in other parameters can either increase or decrease the bearing capacity depending on the characteristics of the cavity (size and location) and footing (size and shape). General solutions for the bearing capacity factor are provided for different variations of the dimensionless parameters. This study also examined various failure mechanisms, including both cavity-independent and cavity-dependent failure mechanisms, associated with circular and square footings and influential parameters. These mechanisms are categorized into three zones for cavity-independent failures and four zones for cavity-dependent failures. The changes in the influential parameters including B/D, S/D, γD/Su, and C/D lead to changes in the type of failure mechanism and the size of the failure zones, while the foundation shape does not have a significant effect on the failure mechanism. Sinkholes and underground cavities annually contribute to infrastructure damage and financial losses. The 1981 incident in Winter Park, Florida, exemplifies the real-world consequences. Previous investigations have been limited to two-dimensional models due to the time-consuming nature and complexity of three-dimensional modeling, but the real-world nature of cavities in three dimensions requires a more comprehensive understanding. This study directly addresses this need by investigating the impact of three-dimensional cavities on the bearing capacity of circular and square building foundations, also known as footings. This study thoroughly investigated the factors influencing the results, encompassing cavity size, depth, soil weight, and off-center position. It extensively explored potential footing failures, providing detailed discussions. Our findings are presented as easy-to-understand maps and charts covering a broad range of potential scenarios. These visual tools can help engineers and researchers accurately estimate the stability of a building's foundation when a cavity is present underneath. In simpler terms, this research has created a handy tool for professionals to predict the potential danger posed by hidden cavities to buildings and infrastructure. This knowledge can then be applied to ensure safer building practices, potentially saving a significant amount of money and preventing accidents in the future. [ABSTRACT FROM AUTHOR]

This study aims to model the temperature evolution near the heater of an in situ heating test for a nuclear waste repository. Based on the governing equation of heat conduction, a mathematical model is established to obtain temporal and spatial temperature distributions in the in situ heating test. Then, semi-analytical solutions are derived using the Laplace and Fourier transforms and their inverse transforms. The corresponding results in the time domain are obtained by conducting the Crump method. The semi-analytical solution is applied to predict temperature change near the heater in two in situ heating tests. Finally, a parametric study is conducted to explore the impacts of some parameters on the temperature evolution of the buffer layer for one prototype repository in situ heating test. The results show that the semi-analytical solution of the proposed model can well predict the temperature change near the heater in the two in situ heating tests. The thermal conductivities of the buffer layer and the rock layer and the thickness of the buffer layer have significant effects on the temperature evolution of the buffer layer in the prototype repository in situ heating test. [ABSTRACT FROM AUTHOR]

The diagrid structural system has become popular in the construction of high-rise buildings in light of significant advantages over other structural systems. The present study explores the effects of the vertical near-fault earthquake component on the axial forces of diagonal elements in steel diagrid structures. Nonlinear time-history analysis was carried out using 11 near-fault earthquake records. A total of nine three-dimensional models of 12, 18, and 24 stories, each with diagonal angles of 45, 63.4, and 71.5 degrees, were designed and analyzed. Due to the three-dimensional modeling complexities of diagrid structures, a method was developed to transform three-dimensional models into two-dimensional ones. Finally, the scenarios with and without the vertical earthquake component were compared. It was found that the incorporation of the vertical earthquake component into the analysis of diagrid structures substantially influenced the axial forces of diagonal elements. This can affect the design load estimation of diagonal elements as the main components of a diagrid structure. [ABSTRACT FROM AUTHOR]

The city phenomenon is dynamic, complex, and has an abundance of data. City Information Modeling (CIM) and Digital Twins (DTs) are new data-driven approaches toward monitoring, controlling, and managing cities. The main purpose of this research is to introduce and raise the concept of CIM and DTs as a necessity in the smart city era for urban planning, design, and management and to implement a practical way to achieve these concepts in the Narmak neighborhood of Tehran City (Iran) as our case study. The primary tool is CityEngine software. A method was discovered to simulate cities where the existence and access to data are severely constrained. First, a Geographic Information System (GIS) database was assembled, then it was analyzed, and the relationships between urban data were determined. Then, programming in CityEngine generated a smart three-dimensional (3D) model with all the city's information. Finally, CIM and DTs led to the production of an integrated 3D database that is smart and interactive. [ABSTRACT FROM AUTHOR]

Controlled‐source electromagnetic methods are applied to survey the electrical resistivity distribution of the subsurface. This work compares normalized electromagnetic field components and transfer functions such as impedance tensors and vertical magnetic transfer functions generated by two independent source polarizations as input data for three‐dimensional inversion. As most other available inversion codes allow for inverting only one of the mentioned input data types, it is unclear which data type is preferable for controlled‐source electromagnetic inversion. Our three‐dimensional non‐linear conjugate gradient inversion code can handle both input data types, facilitating a comparison of normalized electromagnetic field components and transfer functions inversion. Examining inversion results for a three‐dimensional synthetic model with two anomalies, we infer that the transfer functions inversion is favourable for recovering the overall resistivity distribution below the receiver sites in fewer iterations. The inversion of normalized electromagnetic field components produces a sharper image of the anomalies and may be capable of detecting the resistivity distribution below the extended sources, which comes at the price of introducing a more heterogeneous background resistivity in the model. [ABSTRACT FROM AUTHOR]

3D stratum roaming can visualize the complex geomorphology, underground structure and stratum distribution of geotechnical engineering. Conventional 3D stratum roaming technology is generally aimed at roaming outside the 3D stratum model but rarely roams inside the 3D stratum model, and the efficiency of switching between external and internal roaming is low. In practical engineering, especially in geological and geotechnical engineering, the underground structure and stratum situation are critical. Therefore, focusing on this problem, this paper adopts a three-dimensional roaming engine to connect the inside and outside of a three-dimensional model. Based on an internal and external boundary identification method, the combination of external roaming and internal roaming of the three-dimensional stratum model is implemented by using a stratum virtual surface, and lightweight loading is carried out by controlling the stratum virtual surface to establish the internal and external roaming of the 3D stratum model, and to give full play to the advantages of lightweight loading to provide more intuitive and comprehensive geological information for the project. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis is a chronic joint disease mainly characterized by cartilage degeneration. The treatment is challenging due to the lack of blood vessels and nerve supplies in cartilaginous tissue, causing a prominent limitation of regenerative capacity. Hence, we investigated the cellular promotional and anti-inflammatory effects of sericin, Bombyx mori-derived protein, on three-dimensional chondrogenic ATDC5 cell models. The results revealed that a high concentration of sericin promoted chondrogenic proliferation and differentiation and enhanced matrix production through the increment of glycosaminoglycans, COL2A1, COL X, and ALP expressions. SOX-9 and COL2A1 gene expressions were notably elevated in sericin treatment. The proteomic analysis demonstrated the upregulation of phosphoglycerate mutase 1 and triosephosphate isomerase, a glycolytic enzyme member, reflecting the proliferative enhancement of sericin. The differentiation capacity of sericin was indicated by the increased expressions of procollagen12a1, collagen10a1, rab1A, periostin, galectin-1, and collagen6a3 proteins. Sericin influenced the differentiation capacity via the TGF-β signaling pathway by upregulating Smad2 and Smad3 while downregulating Smad1, BMP2, and BMP4. Importantly, sericin exhibited an anti-inflammatory effect by reducing IL-1β, TNF-α, and MMP-1 expressions and accelerating COL2A1 production in the early inflammatory stage. In conclusion, sericin demonstrates potential in promoting chondrogenic proliferation and differentiation, enhancing cartilaginous matrix synthesis through glycolysis and TGF-β signaling pathways, and exhibiting anti-inflammatory properties. [ABSTRACT FROM AUTHOR]

Patient-specific 3D models of the human mandible are finding increasing utility in medical fields such as oral and maxillofacial surgery, orthodontics, dentistry, and forensic sciences. The efficient creation of personalized 3D bone models poses a key challenge in these applications. Existing solutions often rely on 3D statistical models of human bone, offering advantages in rapid bone geometry adaptation and flexibility by capturing a range of anatomical variations, but also a disadvantage in terms of reduced precision in representing specific shapes. Considering this, the proposed parametric model allows for precise manipulation using morphometric parameters acquired from medical images. This paper highlights the significance of employing the parametric model in the creation of a personalized bone model, exemplified through a case study targeting mandibular prognathism reconstruction. A personalized model is described as 3D point cloud determined through the utilization of series of parametric functions, determined by the application of geometrical morphometrics, morphology properties, and artificial neural networks in the input dataset of human mandible samples. With 95.05% of the personalized model's surface area displaying deviations within −1.00–1.00 mm relative to the input polygonal model, and a maximum deviation of 2.52 mm, this research accentuates the benefits of the parametric approach, particularly in the preoperative planning of mandibular deformity surgeries. [ABSTRACT FROM AUTHOR]

The performance of the Plate Indirect Evaporative Cooler (PIEC) can be effectively improved by incorporating baffles in the dry channel. However, in the dimensional influence of the baffles on PIEC performance there remains a research gap. In order to investigate the impact of baffle dimensions on the wet bulb efficiency, namely the average heat transfer coefficient and the cooling capacity of the PIEC, this paper proposed and verified a three-dimensional numerical model and method based on the species transport model and the Euler wall film model. At the same time, in order to obtain the equilibrium point between the enhanced heat transfer performance and the additional resistance induced by baffles, a comprehensive performance evaluation index is introduced. The results indicate that, under the same conditions, (1) the baffle effect on PIEC performance is significant at a lower inlet air velocity, and the wet bulb efficiency of the PIEC with baffles can be improved by 22.8%; (2) the baffle effect on PIEC performance is negative if its relative length exceeds 60% or the primary air inlet velocity surpasses 4 m/s under the conditions specified in this paper; and (3) the baffle effect on PIEC performance is significant when its channel height is lower and its channel width is larger, and the wet bulb efficiency of the PIEC with baffles can be improved by 29.3%. [ABSTRACT FROM AUTHOR]

The underlying mechanism of the ongoing seismic swarm in the Noto Peninsula, Japan, which generates earthquakes at 10 times the average regional rate, remains elusive. We capture the evolution of the subsurface stress state by monitoring changes in seismic wave velocities over an 11-year period. A sustained long-term increase in seismic velocity that is seasonally modulated drops before the earthquake swarm. We use a three-dimensional hydromechanical model to quantify environmentally driven variations in excess pore pressure, revealing its crucial role in governing the seasonal modulation with a stress sensitivity of 6 × 10-9 per pascal. The decrease in seismic velocity aligns with vertical surface uplift, suggesting potential fluid migration from a high-pore pressure zone at depth. Stress changes induced by abnormally intense snow falls contribute to initiating the swarm through subsequent perturbations to crustal pore pressure. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) remains a persistent epidemic, and the emergence of drug-resistant Mycobacterium tuberculosis (Mtb) presents a global healthcare threat. While some new agents have been successfully introduced, innovative technologies to evaluate emerging anti-TB compounds are required to inform transformative approaches. Mtb is an obligate human pathogen, and consequently utilizing models that are consistent with human disease is likely to be critical. We have developed a human 3-dimensional (3-D) cell culture model that reflects human disease gene expression patterns and causes Mtb to become pyrazinamide sensitive in vitro. Here, we identify key differences in virulence between the standard laboratory strain, Mtb H37Rv, and clinical isolates. We demonstrate that Mtb H37Rv is attenuated in the 3-D system, more susceptible to antibiotics and hyperinflammatory compared to clinical isolates. Prolonged in vitro culture of a clinical strain leads to attenuation. We then characterise antibiotic sensitivity of multi-drug-resistant Mtb within the 3-D model and define relative bactericidal activity. Finally, we demonstrate that verapamil increases efficacy of bedaquiline and delamanid antibiotic therapy. Taken together, our findings suggest that studying virulent clinical strains in an advanced cell culture system is a powerful adjunct to established methodologies to evaluate new interventions for TB. [ABSTRACT FROM AUTHOR]

Intense use of groundwater in urban areas requires appropriate monitoring, which in turn necessitates proper data management with employment of increasingly sophisticated statistical methods and mapping tools. An example of such an urban area with intensive use of groundwater is the study area of GeoPot Project, namely Munich (Germany) and its surroundings. The aim of the presented study was to provide a description of the hydrogeochemical characteristics of the aquifers occurring in the Quaternary and Upper Freshwater Molasse (German: Obere Süßwassermolasse – OSM) sediments and to further improve the understanding of interactions between the aquifers. The focus was put on the identification of hydrochemical facies, the chemical signatures of different water types, an understanding of occurring processes, and spatial relationships between the aquifers. In order to deal with hydrogeochemical data generated for this study, as well as with data coming from existing external databanks (e.g. BIS-BY), a methodology of quality assurance was developed. The analytical methods focused on multivariate statistics. To enhance the interpretation of the obtained clusters, a recently developed three-dimensional geological model was used for better understanding and presentation. It was found that in the study area, deeper aquifer systems represent the most distinct hydrogeochemical signature of the Na–HCO3 water type. In the remaining clusters, a transition from deeper (alkaline) to shallow (alkaline-earth) groundwater can be observed. The results of the study can be utilized for improved, sustainable groundwater management. [ABSTRACT FROM AUTHOR]

Oculoplastics is a subspecialty of ophthalmology/dermatology concerned with eyelid, orbital, and lacrimal diseases. Artificial intelligence (AI), with its powerful ability to analyze large data sets, has dramatically benefited oculoplastics. The cutting-edge AI technology is widely applied to extract ocular parameters and to use these results for further assessment, such as screening and diagnosis of blepharoptosis and predicting the progression of thyroid eye disease. AI also assists in treatment procedures, such as surgical strategy planning in blepharoptosis. High efficiency and high reliability are the most apparent advantages of AI, with promising prospects. The possibilities of AI in oculoplastics may lie in three-dimensional modeling technology and image generation. We retrospectively summarize AI applications involving eyelid, orbital, and lacrimal diseases in oculoplastics, and we also examine the strengths and weaknesses of AI technology in oculoplastics. [ABSTRACT FROM AUTHOR]

During the period from 25 August 2012 to 11 December 2013, five typhoons were tracked passing by an observation station near the Xisha Islands in the northern South China Sea (NSCS). An analysis of the temperature observations revealed that the lower ocean layer (below the thermocline) experiences warming prior to the typhoon's arrival. A three-dimensional model was used to analyze the dynamic processes of lower layer ocean warming. The simulations indicate that the upper layer (above the thermocline) is controlled by Ekman dynamics, with intense vertical mixing leading to upper-ocean cooling, consistent with previous understanding. Below the thermocline, the barotropic quasigeostrophic constraint emerges as the pivotal dynamic control of the waters preceding the typhoon, where the vertical velocity induced by Ekman suction drives the circulation in the lower layer. The geostrophic imbalance contributed by the pressure gradient force supplies anticlockwise acceleration and enhances divergence. Due to the negative Ekman suction and the lower layer ocean divergence, there is strong downwelling prior to the typhoon, which induces vertical warm advection leading to the warming of the intermediate ocean. Finally, a simplified estimate is formulated for the lower layer ocean warming preceding the typhoon's arrival. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces have been extensively utilized due to their high hydrophobicity and anti-icing properties. Inspired by the shape of a cross flower, research has utilized circular arc curves and Bessel curves to design a cross flower structure model. Using 3D modeling software for modeling and 3D printing technology to prepare biomimetic microstructures in structural design. The structural shape of the microstructure before and after spray coating was detected using ultra depth of field and laser confocal microscopy. Using Ultra-Ever Dry as a low surface energy substance to alter the wettability of microstructure surfaces. Through surface wettability tests, droplet freezing, and droplet impact tests, the cross shaped biomimetic structure designed by the Bessel curve has a maximum droplet freezing time of 4193 s and a minimum droplet impact time of 9.81 ms. The experimental results indicate that the cross shaped biomimetic structure has good hydrophobicity and broad application prospects. [ABSTRACT FROM AUTHOR]

The effects of corrosion in the serviceability state and capacity state on the failure contingency, life cycle cost (LCC) and optimum repair time (ORT) of reinforced concrete beams were evaluated. Gradual corrosion-induced crack widths were obtained using the cohesive crack model. Deterioration of flexural capacity was examined through a simplified three-dimensional finite-element model. Considering the crack width and capacity as random variables in the gamma process, the LCC and ORT were investigated using a renewal process. Analysis of the effective parameters indicated that the corrosion rate in the serviceability state and the tensile rebar ratio in the capacity state had the most significant effects on the probability of failure (PoF), the LCC and the ORT. With a decrease in the corrosion rate, the PoF reduced and the ORT increased. With an increase in the aspect ratio of the section, the LCC increased and the ORT declined. [ABSTRACT FROM AUTHOR]

Machining of Nomex honeycomb composite (NHC) structures is of critical importance in manufacturing parts to the specifications required in the aerospace industry. However, the special characteristics of the Nomex honeycomb structure, including its composite nature and complex geometry, require a specific machining approach to avoid cutting defects and ensure optimal surface quality. To overcome this problem, this research suggests the adoption of RUM technology, which involves the application of ultrasonic vibrations following the axis of revolution of the UCK cutting tool. To achieve this objective, a three-dimensional finite element numerical model of Nomex honeycomb structure machining is developed with the Abaqus/Explicit software, 2017 version. Based on this model, this research examines the impact of vibration amplitude on the machinability of this kind of structure, including cutting force components, stress and strain distribution, and surface quality as well as the size of the chips. In conclusion, the results highlight that the use of ultrasonic vibrations results in an important reduction in the components of the cutting force by up to 42%, improves the quality of the surface, and decreases the size of the chips. [ABSTRACT FROM AUTHOR]

Interactive deformation via control handles is essential in computer graphics for the modeling of 3D geometry. Deformation control structures include lattices for free‐form deformation and skeletons for character articulation, but this report focuses on cage‐based deformation. Cages for deformation control are coarse polygonal meshes that encase the to‐be‐deformed geometry, enabling high‐resolution deformation. Cage‐based deformation enables users to quickly manipulate 3D geometry by deforming the cage. Due to their utility, cage‐based deformation techniques increasingly appear in many geometry modeling applications. For this reason, the computer graphics community has invested a great deal of effort in the past decade and beyond into improving automatic cage generation and cage‐based deformation. Recent advances have significantly extended the practical capabilities of cage‐based deformation methods. As a result, there is a large body of research on cage‐based deformation. In this report, we provide a comprehensive overview of the current state of the art in cage‐based deformation of 3D geometry. We discuss current methods in terms of deformation quality, practicality, and precomputation demands. In addition, we highlight potential future research directions that overcome current issues and extend the set of practical applications. In conjunction with this survey, we publish an application to unify the most relevant deformation methods. Our report is intended for computer graphics researchers, developers of interactive geometry modeling applications, and 3D modeling and character animation artists. [ABSTRACT FROM AUTHOR]

High‐fidelity digital human modeling has become crucial in various applications, including gaming, visual effects and virtual reality. Despite the significant impact of eyelashes on facial aesthetics, their reconstruction and modeling have been largely unexplored. In this paper, we introduce the first data‐driven generative model of eyelashes based on semantic features. This model is derived from real data by introducing a new 3D eyelash reconstruction method based on multi‐view images. The reconstructed data is made available which constitutes the first dataset of 3D eyelashes ever published. Through an innovative extraction process, we determine the features of any set of eyelashes, and present detailed descriptive statistics of human eyelashes shapes. The proposed eyelashes model, which exclusively relies on semantic parameters, effectively captures the appearance of a set of eyelashes. Results show that the proposed model enables interactive, intuitive and realistic eyelashes modeling for non‐experts, enriching avatar creation and synthetic data generation pipelines. [ABSTRACT FROM AUTHOR]

When heating units are operated in winter, the extreme conditions, such as deep peak regulation and large extraction, can easily lead to a low unit load and severe icing in the wet cooling tower, which threatens the safe operation of the unit. Therefore, it is necessary to study the anti-freezing characteristics of the wet cooling tower. In this paper, a three-dimensional numerical model of a high-level, natural draft wet cooling tower is developed based on the constant heat load method. The influence of withdrawing a certain percentage of circulating water into the bypass on the cooling performance and anti-freezing characteristics of the high-level, natural draft wet cooling tower is investigated. The results show that as the percentage of circulating water bypass extraction increases, the temperature drop of circulating water in the tower continues to increase, but the lowest and the average water temperatures at the bottom of the packing continue to decrease. At the same time, the amount of circulating water entering the tower decreases, the pressure difference between the inside and outside of the tower under the same environmental conditions decreases, and the pumping force of the cooling tower decreases. If the circulating water bypass extraction percentage is less than 10%, it can prevent the circulating water from freezing at the bottom of the packing and, at the same time, try to reduce the temperature of the circulating water entering the condenser to ensure the efficiency of the unit. [ABSTRACT FROM AUTHOR]

This study conducted both three-dimensional physical model tests and numerical back-analyses to examine the performance of a single pile subjected to twin tunnelling beneath the pile toe in dry sand. Moreover, numerical parametric analyses were carried out to assess the impact of working load level and tunnel volume loss on pile behaviour. The findings revealed that the first tunnelling induced a 1.9%dp (pile diameter) settlement in the pile when the pile toe was 0.5 D (tunnel diameter) above the twin tunnels, which had a 1.0% volume loss. The settlement was accompanied by an upward load transfer mechanism. The second tunnelling had a reduced impact and induced only 76% of the settlement caused by the first tunnelling. The study also showed that tunnelling-induced shearing behaviours weakened beneath the pile toe with a decrease in working load, resulting in reduced pile head settlement. Moreover, the computed pile settlement increased by 178% when the tunnel volume loss increased from 0.5% to 2%. The findings of this study offer valuable data for the validation and calibration of numerical models. In addition, the outcome from this study provides useful insights into the prediction of the pile-soil-tunnel interaction when subjected to twin tunnelling. [ABSTRACT FROM AUTHOR]

Objective: Endometriosis affects approximately 10% of women of reproductive age and leads to significant morbidity and financial burden. Consequently, countries such as France and Germany are formulating strategies to combat endometriosis. In this study, we propose the implementation of our three‐dimensional model (3D‐E) to raise awareness about endometriosis and enhance timely diagnosis, treatment, and long‐term care for affected patients. Methods: Based on the adapted Six Sigma Principle and the modified recommendation of Sales et al. for implementing evidence‐based findings into a clinical routine, we first conducted a comprehensive investigation to identify risk factors leading to diagnostic delay of endometriosis. After identifying improvable factors, the applicable options were selected due to defined criteria such as integrability in the clinical routine, cost‐effectiveness, and evidence‐based‐principle. Finally, solutions feasible for health care providers were integrated and the 3D‐E model was established. Results: Some of the main risk factors contributing to diagnostic delays are symptoms acceptance and misinterpreted symptoms, especially if presenting to nongynecologists in cases of extragenital endometriosis with atypical presentation. Therefore, we tried to sensitize colleagues (first dimension) with a review paper in Germany's largest medical journal and started an elective for medical students (second dimension) at our university. In order to involve additional health care professionals in endometriosis care (third dimension), we are preparing the concept of the EndoNurse. Conclusion: The 3D‐E model is a relatively low‐cost, comprehensive, and worldwide adaptable approach for facilitating knowledge transfer, sensitizing health care providers, and improving endometriosis diagnostics and therapy for patients with endometriosis who are in the center of the model. Synopsis: The 3D‐E model could have the potential to be a first step to improve endometriosis awareness and care. [ABSTRACT FROM AUTHOR]

Virtual reality–based learning of neuroanatomy is a new feasible method to explore, visualize, and dissect interactively complex anatomic regions. We provide a new interactive photorealistic three-dimensional (3D) model of sellar region microsurgical anatomy that allows side-by-side views of exocranial and endocranial surfaces to be explored, with the aim of assisting young neurosurgery residents in learning microsurgical anatomy of this complex region. Four head specimens underwent an endoscopic endonasal approach extended to the anterior and posterior skull base to expose the main bony anatomic landmarks of the sellar region. The same bony structures were exposed from a transcranial perspective. By using a photogrammetry method, multiple photographs from both endocranial and exocranial perspectives, different for angulations and depth, were captured, fused, and processed through dedicated software. All relevant bony structures were clearly distinguishable in the 3D model reconstruction, which provides several benefits in neuroanatomy learning: first, it replicates bony structures with high degrees of realism, accuracy, and fidelity; in addition, it provides realistic spatial perception of the depth of the visualized structures and their anatomic relationships; again, the 3D model is interactive and allows a 360° self-guided tour of the reconstructed object, so that the learner can read the bones and their anatomic relationship from all desired points of view. Detailed knowledge of key surgical landmarks representing keyholes and/or anatomic structures to not violate is mandatory for safer surgery, especially for a complex region such as the skull base. Highly accurate virtual and functional neurosurgical models, such as photogrammetry, can generate a realistic appearance to further improve surgical simulators and learn neuroanatomy. [ABSTRACT FROM AUTHOR]

Numerical simulation of radon migration in fractured rock masses is crucial for environmental radon pollution protection, radon tracing technology and the co-exploitation of coal and uranium resources. This paper proposed a novel model based on a fractal discrete fracture network (DFN) to simulate radon migration in fractured rock masses. The paper provided a detailed method for determining the locations of three-dimensional fractures using the multiplicative cascade process. The governing equations for radon migration in fractures and the rock matrix were established and numerically solved using the finite element method. The study developed open-source software DFNRn (Discrete Fracture Network model for Radon migration), which was publicly available on GitHub. The software simulated radon migration in a fractured rock mass with a domain size of 100 m. The results demonstrate that fluid convection in fractures drives radon migration, which is dominant compared to the diffusion process. The accuracy of our proposed model was verified by comparing it with the measured data of the fractured rock. Furthermore, the study investigated the relationship between the percolation threshold of the fracture density P 32 ′ and the key parameters of the DFN. The results show that P 32 ′ decreased with the fractal dimension Df (1.4 ≤ Df ≤ 1.9) and normalization constant α (1.4 ≤ α ≤ 1.8) and is not correlated with the length exponent a (1.2 ≤ a ≤ 2.8). P 32 ′ decreased with the mean orientation angle and has no correlation with the Fisher constant. The radon source term of the rock matrix has the greatest impact on radon migration in fractured rock masses compared to the radon diffusion coefficient and permeability. Highlights: A new approach is proposed to model radon migration in fractured rock masses. An open-source software DFNRn was developed and is publicly available on GitHub. The procedure of the multiplicative cascade method in 3D space is given in detail. [ABSTRACT FROM AUTHOR]

Accurate and efficient 3D medical image segmentation models are critical for clinical applications. However, many models which performed well in recent years have consumed significant computational cost, especially those based on self‐attention. For more efficient and accurate segmentation of medical 3D images, we develop an efficient multiscale spatial attention model for 3D abdominal multiorgan segmentation. We use 1D and 2D kernels in the encoder and decoder modules to simulate 3D kernels to reduce the number of parameters and computational cost. Furthermore, we use the lightweight spatial attention and mixed pooling module to capture cross‐dimensional information, multiscale features, and long‐range contextual information. We achieved a Dice Similarity Coefficient (DSC) of 89.86 and a Normalized Surface Dice (NSD) of 78.2 on the FLARE dataset with only 1183 M GPU memory usage, 9 M parameters, and 193G floating point operations(FLOPs). [ABSTRACT FROM AUTHOR]

Introduction: The present study evaluates the influence of virtual surgical planning with a preoperative 3D resin model on aesthetic and functional outcomes in patients treated by segmental mandibulectomy and reconstruction with fibula-free flap for oral cancer. Methods: All consecutive patients who underwent segmental mandibulectomy and mandibular reconstruction with a fibula-free flap using a 3D template at our department from January 2021 to January 2023 were included in the study. "Patients control" were patients treated by reconstruction with a fibula-free flap without using a 3D template. Three-dimensional modeling was performed by converting from preoperative computed tomography to a stereolithography format to obtain the resin 3D models. Qualitative analysis of anatomical and aesthetic results consisted of the evaluation of the patients' aesthetic and functional satisfaction and the symmetry of the mandibular contour observed at clinical examination. Quantitative analysis was based on the assessment of the accuracy and precision of the reconstruction by comparing preoperative and postoperative computed tomograms as objective indicators. Results: Seven patients (five males and two females, mean age of 65.1 years) were included in the study. All patients showed a symmetric mandibular contour based on the clinical examination. After recovery, six patients (85.7%) considered themselves aesthetically satisfied. The quantitative analysis (assessed in six/seven patients) showed that the mean difference between preoperative and postoperative intercondylar distance, intergonial angle distance, anteroposterior dimension, and gonial angle improved in the 3D template-assisted group. Conclusion: The 3D-printed template for mandibular reconstruction with microvascular fibula-free flap can improve aesthetic outcomes in comparison with standard approaches. [ABSTRACT FROM AUTHOR]

The study aimed to explore an extra-articular screw placement strategy in Stoppa approach. Radiographic data of patients who underwent pelvic computed tomography from January 2016 to June 2017 were imported into Materiaise's interactive medical image control system software for three-dimensional reconstruction. Superior and lower margins of acetabulum and ipsilateral pelvic brim could be observed simultaneously through inlet-obturator view. A horizontal line from superior acetabular margin intersected pelvic brim at point "A" and another vertical line from lower margin intersected pelvic brim at point "B" were drawn, respectively. Lengths form sacroiliac joint to "A" (a), "A" to "B" (b), and "B" to pubic symphysis (c) were measured. Patients were divided into four groups depending on gender and side difference of measured hemi-pelvis: male left, male right, female left, and female right. Lengths of adjacent holes (d) and spanning different holes (e) of different plates were also measured. Mean lengths of a, b, c in four groups were 40.94 ± 1.85 mm, 40.09 ± 1.93 mm, 41.78 ± 3.62 mm, and 39.77 ± 2.23 mm (P = 0.078); 40.65 ± 1.58 mm, 41.48 ± 1.64 mm, 40.40 ± 1.96 mm, and 40.66 ± 1.70 mm (P = 0.265); 57.03 ± 3.41 mm, 57.51 ± 3.71 mm, 57.84 ± 4.40 mm, and 59.84 ± 4.35 mm (P = 0.165), respectively. Mean d length of different plates was 12.23 mm. Average lengths spanning 1, 2, 3 and 4 holes were 19.33 mm, 31.58 mm, 43.80 mm, and 55.93 mm. Our data showed that zones a and c could be safely inserted three and four screws. Penetration into hip joint could be avoided when vacant 3-hole drilling was conducted in zone b. Fracture line in zone b could serve as a landmark for screw placement. [ABSTRACT FROM AUTHOR]

BACKGROUND: The traditional fixation method for femoral neck fractures is three hollow screws inverted triangle fixation, and the optimal fixation method for femoral neck fractures that have not achieved anatomical reduction is inconclusive. OBJECTIVE: To compare the biomechanical properties of cannulated screws internal fixation for sub-capitated femoral neck fracture with different reduction qualities based on finite element analysis. METHODS: The three-dimensional digital model was reconstructed using CT data of the proximal femur from a healthy male volunteer. The femur was modeled to sub-capitated femoral neck fractures. Fracture models were divided into anatomical reduction group, coxa vara group, and coxa valgus group. All fracture model groups were transferred using the standard group, screw depression group, and screw elevation group. A vertical downward stress of 1 400 N was applied to the femoral head at the top of the acetabulum. The displacement and stress distribution of the femur and internal fixator under different fixation methods were observed, and the maximum stress and displacement of the femur and fixator were compared. RESULTS AND CONCLUSION: (1) For anatomical reduction femoral neck fracture, the peak stress of fixation in the standard group, screw depression group and screw elevation group was 41.35, 31.27 and 43.32 MPa, respectively. The maximum peak stress of the femur was found on the screw elevation group (28.58 MPa), and the standard group had the maximum peak displacement. (2) During hip varus, the stresses in the three subgroups were relatively dispersed and even. The peak stress of the femur in the standard group was the smallest, but the peak displacement was the largest. The stability of fixation might be poor. The peak displacement of the femur in the screw depression group was the smallest. (3) In the hip valgus, obvious screw stress concentration appeared in the screw depression group, and the peak displacement was the largest among the three subgroups, and an in-out-in phenomenon appeared. The peak stress of the screws in the screw elevation group was the largest among the three subgroups, but the peak displacement was the smallest. (4) It is concluded that for sub-capitated femoral neck fractures that are completely anatomically reduced, it is recommended to use standard inverted triangular nails for fixation. When the hip varus and hip valgus occur within the allowable range of the reduction standard, it is recommended to use the inverted triangle screw to fix it by rotating the corresponding angle in the same direction as the hip varus or valgus. [ABSTRACT FROM AUTHOR]

BACKGROUND: Calcaneal defects are common in clinical practice. It is difficult for surgeons to evaluate the effect of calcaneal reconstruction due to the complex anatomical structure and motor function of the heel. Finite element analysis has become an effective method for biomechanical behavior simulation and numerical analysis. OBJECTIVE: To compare the clinical effect and biomechanical characteristics of total calcaneal reconstruction with the II-shaped and V-shaped fibular flap. METHODS: CT images of one left foot of a healthy 50-year-old male were acquired. Mimics software was used to obtain the preliminary three-dimensional model. Geomagic software was used to trim and curve the model. The model was imported into Solidworks software to simulate calcaneal reconstruction and complete the pre-processing of finite element calculation. Finally, Ansys software was used to solve the problem. The simulation results were compared with previous literature results to verify the effectiveness of the model. The surgical effect and biomechanical characteristics of the foot in different gait phases based on the simulated stress results were analyzed. RESULTS AND CONCLUSION: (1) Both II-shaped and V-shaped fibular flaps could be used to reconstruct completely missing calcaneus, which could restore the length, width and height of normal calcaneus, and fill up the missing calcaneus bone. (2) Compared with the normal calcaneus, both configurations of fibular flaps showed a tendency for over-concentration of stress after loading. The normal calcaneus stress was mostly concentrated around the calcaneus nodule, the subtalar process and the calcaneus groove, while the stress of the two fibular flaps was mostly concentrated at the junction between the bone flap with the talus and cuboid bones. (3) The maximum stress of calcaneus was different between the two models and normal calcaneus under different simulation conditions, with statistically significant differences (P < 0.05). Compared with the V-shaped fibular flaps, II-shaped fibular flaps had less force change in different gaits and were closer to the normal calcaneus. The V-shaped fibular flap bore excessive stress during the period of push-off, and the grafted bone material may yield under this condition and have the risk of fractures. [ABSTRACT FROM AUTHOR]

The transpedicular procedure has been widely used in spinal surgery. The determination of the best entry point is the key to perform a successful transpedicular procedure. Various techniques have been used to determine this point, but the results are variable. This study was carried out to determine the posterior endpoint of the lumbar pedicle central axis on the standard anterior–posterior (AP) fluoroscopic images. Computer-aided design technology was used to determine the pedicle central axis and the posterior endpoint of the pedicle central axis on the posterior aspect of the vertebra. The standard AP fluoroscopic image of the lumbar vertebral models by three-dimensional printing was achieved. The endpoint projection on the AP fluoroscopic image was determined in reference to the pedicle cortex projection by the measurements of the angle and distance on the established X–Y coordinate system of the radiologic image. The projection of posterior endpoint of the lumbar pedicle central axis were found to be superior to the X-axis of the established X–Y coordinate system and was located on the pedicle cortex projection on the standard AP fluoroscopic image of the vertebra. The projection point was distributed in different sectors in the coordinate system. It was located superior to the X-axis by 18° to 26° at L1, while they were located superior to the X-axis by 12° to 14° at L2 to L5. The projections of posterior endpoints of the lumbar pedicle central axis were located in different positions on the standard AP fluoroscopic image of the vertebra. The determination method of the projection point was helpful for selecting an entry point for a transpedicular procedure with a fluoroscopic technique. [ABSTRACT FROM AUTHOR]

Microwave heating is an emerging alternative pretreatment method for road maintenance in cold seasons. The thermal behavior of asphalt pavement under microwave heating is mainly determined by the complex permittivity of the asphalt mixture. In this study, an innovative approach for calculating the complex permittivity of an asphalt mixture based on a three-dimensional meso-scale heterogeneous structure was proposed. A series of experiments was conducted to verify the accuracy of this approach. The effect of porosity, void size, moisture content and aggregate gradation on the complex permittivity for an asphalt mixture were computationally analyzed based on the validated approach. Moreover, the applicability of commonly used classical dielectric models was analyzed. The classical Lichtenecker–Rother (LR) dielectric model was modified on the basis of simulation data for various conditions. The results showed that the real part of the complex permittivity decreased with the increase in porosity. Some sudden change in the imaginary part of the complex permittivity was observed within the frequency range from 2.6 GHz to 3.9 GHz. A larger air void size would lead to a larger frequency at which sudden change occurs. The real part and imaginary part of the complex permittivity tend to be smaller when more coarse aggregates are replaced with fine aggregates. Both the real part and the imaginary part of the complex permittivity increase with higher moisture content due to the stronger dielectric property of water. Each 1% increase in moisture content would lead to about a 3~4% increase in the real part of the complex permittivity. The determination coefficients R2 for the real part and the imaginary part of the complex permittivity fitted by the modified Brown model were the maximum values, which were 0.922 and 0.980, respectively. The method presented in this study is useful for transportation agencies to optimize microwave heating during winter maintenance. [ABSTRACT FROM AUTHOR]