Three-dimensional Analysis Research Articles

Midterm Results of Physician-Modified Endograft in Juxtarenal Abdominal Aortic Aneurysm Using Three-Dimensional Model-Assisted Planning and Intraoperative Three-Dimensional Image Analysis

Midterm Results of Physician-Modified Endograft in Juxtarenal Abdominal Aortic Aneurysm Using Three-Dimensional Model-Assisted Planning and Intraoperative Three-Dimensional Image Analysis

A two-dimensional photographic and three-dimensional digital dental model comparative analysis in maxillary anterior teeth

Objective: To assess the accuracy of two-dimensional (2D) photographs in measuring esthetic parameters of the maxillary anterior teeth by comparing them with measurements obtained from three-dimensional (3D) dental models. Methods: A total of one hundred volunteers (49 males, 51 females, aged 18-23 years) were recruited from School and hospital of Stomatology, Wuhan University from January to February 2024. 3D digital models of their dentitions were obtained using an intraoral scanner, and standardized frontal 2D intraoral photographs were captured with a digital camera. The lengths, widths and width/length ratio of the bilateral incisors, lateral incisors and canines were measured on both the 3D digital models and the 2D intraoral photographs. The width ratios of adjacent maxillary anterior were also calculated on the 2D intraoral photographs and the frontal view of 3D digital models. Results: The widths of lateral incisors [(5.85±0.60) mm] and canines [(4.73±0.71) mm] and the lengths of canines [(8.72±0.96) mm] in the 2D intraoral photographs were significantly lower than those in 3D digital models [(6.65±0.59), (7.76±0.60), (8.90±0.86) mm] (t=-18.24, P<0.001; t=-54.43, P<0.001; t=-4.40, P<0.001), while there were no significant differences in the lengths and widths of the other teeth (P>0.05). The width/length ratios measured from the 2D intraoral photographs for the lateral incisors and canines (0.74±0.08, 0.55±0.08) were significantly lower than those measured in the 3D digital models (0.84±0.09, 0.88±0.09) (t=-19.68, P<0.001; t=-50.21, P<0.001), and the width/length ratio of the central incisors showed no significant difference between the two groups (P>0.05). The width ratios of canines/lateral incisors and lateral incisors/central incisors measured on the 2D intraoral photographs (0.72±0.06, 0.85±0.11) were significantly smaller than those measured in the frontal view of 3D digital models (0.75±0.06, 0.89±0.11) (t=-9.31, P<0.001; t=-6.58, P<0.001). Conclusions: There is a difference between 2D and 3D measurements results of teeth in the esthetic area and the magnitude of the difference varies with their position in the dental arch. When analyzing the measurement of the anterior teeth, it is necessary to choose the appropriate method according to the target tooth position.

Reliability of Obstacle-Crossing Parameters during Overground Walking in Young Adults

We aimed to evaluate the intra-session relative and absolute reliability of obstacle-crossing parameters during overground walking in young adults, and to determine the number of trials required to ensure reliable assessment. We analysed data from 43 young male adults who were instructed to walk at a self-selected velocity on a pathway and to step over an obstacle (height = 15 cm; width = 80 cm, thickness = 2 cm) three times. Spatial–temporal gait parameters of the approaching and crossing phases (i.e., before and after the obstacle) and obstacle clearance parameters (i.e., vertical and horizontal distance between the foot and the obstacle during crossing) were computed using a three-dimensional motion analysis system. Intraclass correlation coefficients were used to compute the relative reliability, while standard error of measurement and minimal detectable change were used to assess the absolute reliability for all possible combinations between trials. Results showed that most spatial–temporal gait parameters and obstacle clearance parameters are reliable using the average of three trials. However, the mean of the second and third trials ensures the best relative and absolute reliabilities of most obstacle-crossing parameters. Further works are needed to generalize these results in more realistic conditions and in other populations.

An integrated three-dimensional aeromechanical analysis for the prediction of stresses on modern coaxial rotors

This paper presents the first application of an Integrated Three-Dimensional aeromechanical analysis—defined as the coupled solution of three-dimensional finite element-based structural dynamics with a three-dimensional Reynolds-Averaged Navier-Stokes-based fluid dynamics—to predict the stresses on a modern coaxial rotor. The coupling was carried out with the University of Maryland’s structural dynamic solver X3D and the U.S. Army’s CREATETM–AV Helios suite of fluid dynamic solvers. A modern four-bladed hingeless coaxial rotor model—inspired by the gross dimensions of the Sikorsky S-97 Raider but generic and open source otherwise—is developed as a demonstration test case. The new structural solver is driven by parallel and scalable solvers and advanced high performance computing. It is enabled by high-order three-dimensional brick finite elements unified with multibody dynamics, integrated aerodynamics, and a special 3D-to-1D fluid-structure interfaces refines the power of delta-coupling procedure while retaining the advantages of existing CFD mesh motion schemes. The analysis predicts the three-dimensional stresses on the rotor blades and hub, together with the deformations, airloads, and wake, in an integrated manner. Two flight conditions are studied: a low-speed flight at 37 knots and a high-speed flight at 150 knots. Interesting three-dimensional unsteady stress patterns are revealed all across the blade but particularly inboard of 50% rotor radius—patterns that change from flight to flight and have remained invisible until now—since they could neither be predicted nor measured in flight. The maximum axial stresses exhibited 3/rev variation at low speed, and 2/rev variation at high speed flight. The lower rotor carried higher oscillatory stress burden at low speed, whereas both the rotors shared the same stress burden at high speed flight. The key conclusion is that such analysis is now indeed possible, and the stress patterns they reveal provide deeper insights into the dynamics of advanced rotors, and these might provide a path toward mitigating them in the future.

Feature analysis of joint motion in paralyzed and non-paralyzed upper limbs while reaching the occiput: A cross-sectional study in patients with mild hemiplegia.

The reaching motion to the back of the head with the hand is an important movement for daily living. The scores of upper limb function tests used in clinical practice alone are difficult to use as a reference when planning exercises for movement improvements. This cross-sectional study aimed to clarify in patients with mild hemiplegia the kinematic characteristics of paralyzed and non-paralyzed upper limbs reaching the occiput. Ten patients with post-stroke hemiplegia who attended the Department of Rehabilitation Medicine of the Jikei University Hospital and met the eligibility criteria were included. Reaching motion to the back of the head by the participants' paralyzed and non-paralyzed upper limbs was measured using three-dimensional motion analysis, and the motor time, joint angles, and angular velocities were calculated. Repeated measures multivariate analysis of covariance was performed on these data. After confirming the fit to the binomial logistic regression model, the cutoff values were calculated using receiver operating characteristic curves. Pattern identification using random forest clustering was performed to analyze the pattern of motor time and joint angles. The cutoff values for the movement until the hand reached the back of the head were 1.6 s for the motor time, 55° for the maximum shoulder joint flexion angle, and 145° for the maximum elbow joint flexion angle. The cutoff values for the movement from the back of the head to the hand being returned to its original position were 1.6 s for the motor time, 145° for the maximum elbow joint flexion angle, 53°/s for the maximum angular velocity of shoulder joint abduction, and 62°/s for the maximum angular velocity of elbow joint flexion. The numbers of clusters were three, four, and four for the outward non-paralyzed side, outward and return paralyzed side, and return non-paralyzed side, respectively. The findings obtained by this study can be used for practice planning in patients with mild hemiplegia who aim to improve the reaching motion to the occiput.

Research on the Correction of Soil Pressure Distribution Pattern in Circular Working Wells in Soft Soil Areas

This paper investigates the distribution characteristics of earth pressure on circular caisson foundations in soft soil areas based on practical engineering considerations. Utilizing a three-dimensional numerical analysis model and a displacement-based method for earth pressure calculation, the lateral earth pressure on the retaining structure is examined. Adjustments are made to the distribution pattern of earth pressure on circular caisson foundations in soft soil areas. The study demonstrates that the radius of the caisson significantly influences the spatial distribution of soil pressure. Additionally, empirical formulas for the depth and radius of the reduction in soil pressure around circular caisson foundations are obtained through the research. Comparative analysis reveals that the modified earth pressure planar foundation beam method, which accounts for the arching effect, is simpler, features more mature parameter selection, and is more cost-effective than the three-dimensional finite element method. In comparison to the standard planar elastic foundation beam method for earth pressure, it aligns more closely with the actual direction of displacement.

3D ocean assessments reveal that fisheries reach deep but marine protection remains shallow

The wave of new global conservation targets, the conclusion of the High Seas Treaty negotiations, and the expansion of extractive use into the deep sea call for a paradigm shift in ocean conservation. The current reductionist 2D representation of the ocean to set targets and measure impacts will fail at achieving effective biodiversity conservation. Here, we develop a framework that overlays depth realms onto marine ecoregions to conduct the first three-dimensional spatial analysis of global marine conservation achievements and fisheries footprint. Our novel approach reveals conservation gaps of mesophotic, rariphotic, and abyssal depths and an underrepresentation of high protection levels across all depths. In contrast, the 3D footprint of fisheries covers all depths, with benthic fishing occurring down to the lower bathyal and mesopelagic fishing peaking in areas overlying abyssal depths. Additionally, conservation efforts are biased towards areas where the lowest fishing pressures occur, compromising the effectiveness of the marine conservation network. These spatial mismatches emphasize the need to shift towards 3D thinking to achieve ocean sustainability.

An Improved Positive Displacement Pump Model Accounting for Suction Cavitation

Abstract Positive displacement (PD) pumps are widely employed in industrial settings due to their inherent simplicity and reliability, serving a diverse range of applications from slurry transport to jet washing. Although their operational principles are straightforward, the fluid dynamics of the pumped medium exhibit non-trivial characteristics, including intricate transient phenomena. Consequently, a comprehensive fluid dynamic description, such as a three-dimensional RANS analysis, presents challenges due to its demanding computational requirements. While simpler analytical PD pump models are available, they often fail to adequately represent the primary system behaviors, particularly when dealing with cavitation. Motivated by these challenges, this study aims to develop a novel one-dimensional model for PD pumps, offering a representation of essential fluid phenomena without imposing significant computational burdens. After assessing the relative importance of the fluid dynamic behaviors that the model must capture, we construct a pump model based on a one-dimensional fluid description and solve it using a second-order in time and space MUSCL-TVD scheme. The model's validity is confirmed by its application to both single-chamber and three-chamber diaphragm PD pumps, which are instrumented for experimental validation. The results of the one-dimensional model exhibit strong agreement with physical experiments, both in controlled laboratory environments and field conditions. This success suggests a promising approach for industrial applications.

Three-Dimensional Numerical Field Analysis in Transformers to Identify Losses in Tape Wound Cores.

To find the total core losses in 1-phase medium-frequency transformers, a 3D numerical field analysis was carried out. The proposed numerical modeling was based on the extended iterative homogenization method (IHM) developed by the authors. The achieved calculation results were validated by the corresponding values obtained experimentally, and a reasonably close agreement was obtained.

Three-dimensional magnetic resonance imaging-based statistical shape analysis and machine learning-based prediction of patellofemoral instability.

This study performed three-dimensional (3D) magnetic resonance imaging (MRI)-based statistical shape analysis (SSA) by comparing patellofemoral instability (PFI) and normal femur models, and developed a machine learning (ML)-based prediction model. Twenty (19 patients) and 31 MRI scans (30 patients) of femurs with PFI and normal femurs, respectively, were used. Bone and cartilage segmentation of the distal femurs was performed and subsequently converted into 3D reconstructed models. The pointwise distance map showed anterior elevation of the trochlea, particularly at the central floor of the proximal trochlea, in the PFI models compared with the normal models. Principal component analysis examined shape variations in the PFI group, and several principal components exhibited shape variations in the trochlear floor and intercondylar width. Multivariate analysis showed that these shape components were significantly correlated with the PFI/non-PFI distinction after adjusting for age and sex. Our ML-based prediction model for PFI achieved a strong predictive performance with an accuracy of 0.909 ± 0.015, and an area under the curve of 0.939 ± 0.009 when using a support vector machine with a linear kernel. This study demonstrated that 3D MRI-based SSA can realistically visualize statistical results on surface models and may facilitate the understanding of complex shape features.

Three-dimensional flutter analysis of a novel circular sandwich plate employing hyperbolic shear deformation theory

Magnetorheological elastomers (MREs) Characterize a category of intelligent materials renowned for their distinct responsiveness to external magnetic fields, demonstrating swift alterations in their mechanical and rheological characteristics. The amalgamation of graphene platelets (GPLs) with MREs, termed GPL-reinforced MRE (GPL-MRE), heralds a novel material category imbued with the adaptive traits of MREs and the structural robustness inherent in GPLs. Such compositional innovation renders this material exceptionally suited for an array of applications across diverse structural frameworks. This research endeavors to scrutinize the flutter boundary of a smart circular sandwich plate featuring a core layer infused with GPL-MRE and variable stiffness composite laminated (VSCL) face layers within the context of supersonic airflow and resting upon a viscoelastic foundation. A novel hyperbolic shear deformation theory is invoked to delineate the displacement field of the sandwich plate. The mechanical properties of the mid-layer are delineated employing the Halpin-Tsai micromechanical methodology. The study probes the effect of supersonic airflow on the structure employing the first-order Piston theory (FPT) in polar coordinates. Hamilton's principle is utilized for deriving the equation of motion governing the structural dynamics in the Finite Element format. Paramount to this investigation is the exploration of assorted parameters and their impact on the flutter occurrence of the structure.

Optimization of automotive aerodynamic performance based on DOE

Based on a new-energy sedan as the research object, the Design of Experiments (DOE) optimization integrated grid deformation method was used to optimize and improve the aerodynamic performance of a certain development model. A three-dimensional flow field comparison analysis was conducted on the improved areas of the whole vehicle flow field, and wind tunnel tests were conducted for verification. Through CFD simulation and wind tunnel test verification, the accuracy of the CFD simulation method was verified. The engineering feasible DOE optimization recommended area for the whole vehicle was summarized. The optimal prediction results based on the DOE optimization method and the corresponding CFD simulation results were analyzed for reliability. The correlation between the optimization variables and the target function was analyzed, and 6 counts reduced the whole vehicle drag coefficient by adjusting the optimization variables within a small range. Finally, wind tunnel tests were used to verify the effectiveness of the optimized variable scheme. The results provide an important reference for the optimization design and development of vehicle aerodynamic performance.

Characteristics and prognostic value of cardiac magnetic resonance strain analysis in patients with different phenotypes of heart failure

BackgroundStrain analysis of cardiac magnetic resonance imaging (CMR) is important for the prognosis of heart failure (HF). Herein, we aimed to identify the characteristics and prognostic value of strain analysis revealed by CMR in different HF phenotypes.MethodsParticipants with HF, including HF with reduced ejection fraction, HF with mildly reduced ejection fraction, and HF with preserved ejection fraction, and controls were enrolled. The baseline information and clinical parameters of participants were collected, and echocardiography and CMR examination were performed. Three-dimensional strain analysis was performed in the left ventricle, right ventricle, left atrium, and right atrium using CMR. A multifactor Cox risk proportional model was established to assess the influencing factors of cardiovascular adverse events in patients with HF.ResultsDuring a median follow-up of 999 days (range: 616–1334), 20.6% of participants (73/354) experienced adverse events (HF readmission and/or cardiovascular death). Univariable Cox regression revealed that a 1% increase in left atrial global longitudinal strain (LAGLS) was associated with a hazard ratio (HR) of 1.21 [95% confidence interval (CI):1.15–1.28; P &amp;lt; 0.001]. Left ventricular global circumferential strain (LVGCS) (HR, 1.18; 95% CI: 1.12–1.24; P &amp;lt; 0.001), and left ventricular global longitudinal strain (LVGLS) (HR, 1.27; 95% CI: 1.20–1.36; P &amp;lt; 0.001) were also associated with HF hospitalizations and cardiovascular deaths. Among clinical variables, hypertension (HR, 2.11; 95% CI: 1.33–13.36; P = 0.002), cardiomyopathy (HR, 2.26; 95% CI: 1.42–3.60; P &amp;lt; 0.001) were associated with outcomes in univariable analysis. Multivariable analyses revealed that LAGLS (95% CI: 1.08–1.29; P &amp;lt; 0.001), LVGLS (95% CI:1.08–1.29; P &amp;lt; 0.001) and LVGCS (95% CI: 1.19–1.51; P &amp;lt; 0.001) were significantly associated with outcomes. Among clinical variables, hypertension (95% CI: 1.09–3.73; P &amp;lt; 0.025) remained a risk factor.ConclusionCMR plays an obvious role in phenotyping HF. Strain analysis, particularly left atrial and left ventricular strain analysis (LAGLS, LVGLS, and LVGCS) has good value in predicting adverse outcome events.

Fast computational approach with prior dimension reduction for three-dimensional chemical component analysis using CT data of spectral imaging.

Spectral image (SI) measurement techniques, such as X-ray absorption fine structure (XAFS) imaging and scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) or electron energy loss spectroscopy (EELS), are useful for identifying chemical structures in composite materials. Machine-learning techniques have been developed for automatic analysis of SI data, and their usefulness has been proven. Recently, an extended measurement technique combining SI with a computed tomography (CT) technique (CT-SI), such as CT-XAFS and STEM-EDS/EELS tomography, was developed to identify the three-dimensional (3D) structures of chemical components. CT-SI analysis can be conducted by combining CT reconstruction algorithms and chemical component analysis based on machine learning techniques. However, this analysis incurs high computational costs owing to the size of the CT-SI datasets. To address this problem, this study proposed a fast computational approach for 3D chemical component analysis in an unsupervised learning setting. The primary idea for reducing the computational cost involved compressing the CT-SI data prior to CT computation and performing 3D reconstruction and chemical component analysis on the compressed data. The proposed approach significantly reduced the computational cost without losing information about the 3D structure and chemical components. We experimentally evaluated the proposed approach using synthetic and real CT-XAFS data, which demonstrated that our approach achieved a significantly faster computational speed than the conventional approach while maintaining analysis performance. As the proposed procedure can be implemented with any CT algorithm, it is expected to accelerate 3D analyses with sparse regularized CT algorithms in noisy and sparse CT-SI datasets.

Pilot study for three-dimensional cephalometric Enlow's counterpart analysis: Vertical track. Two-dimensional and three-dimensional comparison.

The introduction of cone beam computed tomography (CBCT) in dentistry has given orthodontists the possibility of studying craniofacial structures in three dimensions. Despite the possibility to obtain lateral cephalograms synthesized from CBCT, this approach still does not provide a fully three-dimensional evaluation of the patient's anatomy. While there has been some success in adapting traditional two-dimensional cephalometric analyses to three dimensions, the specific application of Enlow's cephalometric analysis using CBCT remains unexplored. This pilot study aims to introduce a novel approach for performing Enlow's vertical track analysis using CBCT images. Eighteen CBCT images of skeletal Class I (ANB = 2 ± 2) subjects (12 males and 6 females, aged from 9 to 19 years) with no history of previous orthodontic treatment were selected. For each subject, 2D Enlow's vertical track analysis was performed on lateral cephalograms extracted from the CBCT images, and separately, 3D vertical track analysis was directly performed on the CBCT images. To validate the proposed method, we compared the differences between the posterior vertical counterpart (PVC) and the middle vertical counterpart (MVC), as well as between the middle vertical counterpart (MVC) and the anterior vertical counterpart (AVC), as obtained from both the two-dimensional and three-dimensional analyses. The Kolmogorov-Smirnov normality test was applied for each variable to check whether data were normally distributed and a paired Student's t-test was performed. The level of statistical significance was .05. The comparison between three-dimensional PVC-MVC (-0.43 ± 0.37 cm) and two-dimensional PVC-MVC (-0.53 ± 0.36 cm) revealed no statistical difference (P = .27). Similarly, no significant difference (P = .28) was observed between two-dimensional MVC-AVC (-0.56 ± 0.34 cm) and three-dimensional MVC-AVC (-0.47 ± 0.37 cm). The method proposed by this study to realize the vertical track analysis on 3D images is valid and superimposable on that described by Enlow on lateral cephalograms.

Ascent and Attachment in Pea Plants: A Matter of Iteration

Pea plants (Pisum sativum L.) can perceive the presence of potential supports in the environment and flexibly adapt their behavior to clasp them. How pea plants control and perfect this behavior during growth remains unexplored. Here, we attempt to fill this gap by studying the movement of the apex and the tendrils at different leaves using three-dimensional (3D) kinematical analysis. We hypothesized that plants accumulate information and resources through the circumnutation movements of each leaf. Information generates the kinematical coordinates for the final launch towards the potential support. Results suggest that developing a functional approach to grasp movement may involve an interactive trial and error process based on continuous cross-talk across leaves. This internal communication provides evidence that plants adopt plastic responses in a way that optimally corresponds to support search scenarios.

E3 ubiquitin ligase UBR5 promotes gemcitabine resistance in pancreatic cancer by inducing O-GlcNAcylation-mediated EMT via destabilization of OGA.

Pancreatic cancer (PC) is among the deadliest malignancies, with an extremely poor diagnosis and prognosis. Gemcitabine (GEM) remains the first-line drug for treating PC; however, only a small percentage of patients benefit from current immunotherapies or targeted therapies. Resistance to GEM is prevalent and affects long-term survival. We found that ubiquitin-protein ligase E3 module N-recognition 5 (UBR5) is a therapeutic target against GEM resistance. UBR5 was markedly upregulated in clinical GEM-resistant PC samples and GEM-resistant PC cells. UBR5 knockdown markedly increased GEM sensitivity in GEM-resistant PC cell lines. UBR5-mediated GEM resistance was accompanied by activation of epithelial-mesenchymal transition (EMT) and could be mitigated by inhibiting EMT. Further analysis revealed that UBR5 promoted GEM resistance in PC cells by enhancing O-GlcNAcylation-mediated EMT. In addition, UBR5 knockdown resulted in increased O-GlcNAase (OGA) levels, an essential negatively regulated enzyme in the O-GlcNAcylation process. We identified a negative association between OGA and UBR5 levels, which further supported the hypothesis that O-GlcNAcylation-mediated GEM resistance induced by UBR5 is OGA-dependent in PC cells. Mechanistic studies revealed that UBR5 acts as an E3 ubiquitin ligase of OGA and regulates O-GlcNAcylation by binding and modulating OGA, facilitating its degradation and ubiquitination. Additionally, high-throughput compound library screening using three-dimensional protein structure analysis and drug screening identified a Food and Drug Administration drug, Y-39983 dihydrochloride, as a potent GEM sensitiser and UBR5 inhibitor. The combination of Y-39983 dihydrochloride and GEM attenuated tumour growth in a mouse xenograft tumour model. Collectively, these data demonstrated that UBR5 plays a pivotal role in the sensitisation of PC to GEM and provides a potential therapeutic strategy to overcome GEM resistance.

An Online Hotel Selection Method With Three-Dimensional Analysis of Reviews' Helpfulness

The multi-attribute decision-making method based on online reviews has been widely used in addressing the hotel selection problem. However, due to information overload and the presence of fake reviews, traditional hotel selection methods that rely solely on unverified review analysis can affect the outcome of hotel selections. In this study, a novel three-dimensional helpful review analysis model based multi-attribute decision-making approach for hotel selection is established. Firstly, a new three-dimensional helpful review analysis model that effectively filters out sentiment inconsistency reviews, topic inconsistency reviews, and reviews from invalid sources is proposed. Secondly, this study employs TF-IDF and LDA to extract attributes for hotel selection. We further utilize BERT to extract sentiment level for each attribute. Then, a ranking result for alternative hotels is obtained using a combination compromise solution method (CoCoSo). Finally, we demonstrate its effectiveness and feasibility through a case study of selecting the optimal hotel from TripAdvisor.com.

Development of branchial ionocytes in embryonic and larval stages of cloudy catshark, Scyliorhinus torazame.

In teleost fish, branchial ionocytes are important sites for osmoregulation and acid-base regulation by maintaining ionic balance in the body fluid. During the early developmental stages before the formation of the gills, teleost ionocytes are localized in the yolk-sac membrane and body skin. By comparing with teleost fish, much less is known about ionocytes in developing embryos of elasmobranch fish. The present study investigated the development of ionocytes in the embryo and larva of cloudy catshark, Scyliorhinus torazame. We first observed ionocyte distribution by immunohistochemical staining with anti-Na+/K+-ATPase (NKA) and anti-vacuolar-type H+-ATPase (V-ATPase) antibodies. The NKA- and V-ATPase-rich ionocytes appeared as single cells in the gill filaments from stage 31, the stage of pre-hatching, while the ionocytes on the body skin and yolk-sac membrane were also observed. From stage 32, in addition to single ionocytes on the gill filaments, some outstanding follicular structures of NKA-immunoreactive cells were developed to fill the inter-filament region of the gill septa. The follicular ionocytes possess NKA in the basolateral membrane and Na+/H+ exchanger 3 in the apical membrane, indicating that they are involved in acid-base regulation like single NKA-rich ionocytes. Three-dimensional analysis and whole-mount immunohistochemistry revealed that the distribution of follicular ionocytes was limited to the rostral side of gill septum. The rostral sides of gill septum might be exposed to faster water flow than caudal side because the gills of sharks gently curved backward. This dissymmetric distribution of follicular ionocytes is considered to facilitate efficient body-fluid homeostasis of catshark embryo.

Analysis of prefabricated myofunctional appliances with different overjet and bumper designs: a three-dimensional finite element analysis

BackgroundPrefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method.MethodsWe established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded.ResultsThe deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively.ConclusionThe prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.