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Slicing 3D polygonal meshes is a fundamental operation in various applications such as virtual surgery, garment simulation, and game development. Existing methods primarily slice meshes using either a single line or a set of line segments approximating a smooth curve. This paper introduces a novel approach to freely slice a triangle mesh using a freeform curve without discretizing it into line segments. The user draws a stroke on the screen, defining the desired cutting trajectory. Subsequently, a freeform curve approximating this stroke is generated and extended into a ruled surface in the user’s viewing direction. To efficiently compute intersections between the ruled surface and a triangle mesh, the Line–Surface Intersection (LSI) problem is broken down into two subproblems: Plane–Curve Intersection (PCI) followed by Line–Line Intersection (LLI). Intersection points are then connected to form polylines, effectively cutting the mesh into multiple submeshes. To ensure the solidity of the submeshes, cross-sections are generated by trimming the ruled surface along the polylines and merged with the corresponding submeshes. Our method empowers users to slice triangle meshes along arbitrary trajectories encompassing both straight and freely curved paths while preserving efficiency and accuracy. The effectiveness of the proposed approach is demonstrated through experimental results showing various examples of mesh slicing.

Neurofeedback can be utilized to treat various neuropsychiatric disorders in children. However, therapists primarily set threshold values for neurofeedback training. Thus, the training effect becomes subjective owing to the experience of the therapist. A clinically inexperienced therapist could set inappropriate thresholds, rendering the training ineffective. In this study, an effective neurofeedback system that includes signal processing of large amount of electroencephalogram (EEG) data and auto thresholding and provides various training contents was developed. The system uses a method that determines optimal threshold values, which are significant for an effective neurofeedback system. The success or failure of the activation and inhibition of specific EEG frequencies was determined based on these threshold values. The system determined an optimal threshold value to obtain the target success rate using a numerical optimization technique. The success or failure feedback for the reward and inhibit EEG frequencies was generated using auto thresholding. This feedback was sent to the training contents by the inter-process communication module to control the contents. Most training content was implemented as serious video games by using a commercial game engine. Success feedback on reward EEG frequency leads to game progress. By contrast, failure feedback on inhibiting EEG frequency hinders game progress. Consequently, the user gains the self-regulation ability to enhance the reward EEG frequency and suppress the inhibit EEG frequency. A pilot study involving five children with attention deficiency was conducted to demonstrate the effectiveness of the developed system. The results demonstrated that the childrent’s attention improved after neurofeedback training.

Objectives: To identify and estimate the non-point source (NPS) pollution loads in the Yongdam watershed, and to take an appropriate NPS management plan suitable for the environmental conditions of the sub-basin of Yongdam watershed. Methods: The NPS pollutant loads of the Yongdam watershed was investigated to establish the hydrological simulation program-fortran (HSPF) model for the study area so that the characteristics of non-point runoff were simulated. Furthermore, the detailed catchment area subject to non-point pollution management was selected and the effect of reducing non-point pollution was examined based on the various simulation results. Results and Discussion: The three sub-basins, including specific component of catchments, of Yongdam watershed was selected according to the load intensity and distribution of NPS pollution. The result of analyzing the load flowing into the downstream by rainfall intensity revealed that the pollutant load accounted for 11.8~19.9% in the dry season, and for Jinan-cheon sub-basin the load was high in the range of 10~30 mm while Janggye-cheon sub-basin and downstream of Janggye-cheon junction sub-basin showed a high load in the range 30~60 mm. In addition, the load duration curve (LDC) showed the excess frequency of BOD load was high when the flow rate increased at the end of stream for each sub-basin, whereas the load excess frequency was high in T-P in the entire flow range. LDC analysis led to us that the water quality of stream was affected by point and non-point pollutants in a complex way. When NPS pollution reduction facilities were installed by selecting 10 detailed catchments with high need for NPS pollution management, the reduction of T-P load was estimated to be reduced by 1.85 kg/d in Jinan-cheon sub-basin, 6.40 kg/d in Janggye-cheon sub-basin, and 6.58 kg/d in downstream of Janggye-cheon junction sub-basin. Conclusions: Through various simulation experiments using the HSPF model, it was feasible to select an catchment subject to NPS pollution control in detail and evaluate the effect of reducing NPS pollution.

Due to the outbreak of the SARS-CoV-2 virus, drug repurposing and Emergency Use Authorization have been proposed to treat the coronavirus disease 2019 (COVID-19) during the pandemic. While the efficiency of the drugs has been discussed, it was identified that certain compounds, such as chloroquine and hydroxychloroquine, cause QT interval prolongation and potential cardiotoxic effects. Drug-induced cardiotoxicity and QT prolongation may lead to life-threatening arrhythmias such as torsades de pointes (TdP), a potentially fatal arrhythmic symptom. Here, we evaluated the risk of repurposed pyronaridine or artesunate-mediated cardiac arrhythmias alone and in combination for COVID-19 treatment through in vitro and in silico investigations using the Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative. The potential effects of each drug or in combinations on cardiac action potential (AP) and ion channels were explored using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and Chinese hamster ovary (CHO) cells transiently expressing cardiac ion channels (Nav1.5, Cav1.2, and hERG). We also performed in silico computer simulation using the optimized O’Hara-Rudy human ventricular myocyte model (ORd model) to classify TdP risk. Artesunate and dihydroartemisinin (DHA), the active metabolite of artesunate, are classified as a low risk of inducing TdP based on the torsade metric score (TMS). Moreover, artesunate does not significantly affect the cardiac APs of hiPSC-CMs even at concentrations up to 100 times the maximum serum concentration (Cmax). DHA modestly prolonged at APD90 (10.16%) at 100 times the Cmax. When considering Cmax, pyronaridine, and the combination of both drugs (pyronaridine and artesunate) are classified as having an intermediate risk of inducing TdP. However, when considering the unbound concentration (the free fraction not bound to carrier proteins or other tissues inducing pharmacological activity), both drugs are classified as having a low risk of inducing TdP. In summary, pyronaridine, artesunate, and a combination of both drugs have been confirmed to pose a low proarrhythmogenic risk at therapeutic and supratherapeutic (up to 4 times) free Cmax. Additionally, the CiPA initiative may be suitable for regulatory use and provide novel insights for evaluating drug-induced cardiotoxicity.

Objectives To evaluate the difference between healthcare professionals (HCPs) and adults with spinal cord injury (SCI) in Asia regarding knowledge and interpretation of ‘exercise intensity’ for aerobic exercise prescription.Methods and study design A survey was distributed to practising HCP and adults with SCI. It was completed in participants’ local language on topics related to the importance of exercise frequency, intensity, time and type; methods for monitoring and terms related to exercise intensity prescription. χ2 analysis was used to detect differences in HCP or those with SCI.Results 121 HCP and 107 adults with an SCI ≥1 years (C1–L4) participated. Responses revealed 61% of all HCP ranked ‘intensity’ being most important whereas only 38% respondents from the SCI group ranked it as high importance (p=0.008). For those with SCI, ‘frequency’ was most important (61%) which was significantly higher than the 45% selected by HCPs (p=0.030). Of the 228 respondents on average only 34% believed that the terms, ‘moderate’ and ‘vigorous’ provided enough information for aerobic exercise intensity prescription. HCP most often used HR methods compared with the SCI group (90% vs 54%; p

Abstract Background Dyspnea is a common symptom in patients presenting to the emergency department. It has a variety of causes that range from non-urgent to life-threatening. One episode of dyspnea in a healthy young person is easy to overlook. However, if the symptoms occur after physically or emotionally stressful events, careful evaluation needs to be undertaken because it may be associated with Takotsubo syndrome, which is rarely expected but can be fatal. Herein, we report the case of Takotsubo syndrome in a healthy young woman who arrived at the emergency department after experiencing a short single episode of dyspnea following a minor surgery. Case presentation A 23-year old woman with no underlying chronic disease underwent closed reduction surgery for a nasal bone fracture under general anesthesia (with sevoflurane as the anesthetic). Approximately 5 h later, she presented to the emergency department with dyspnea, which improved soon upon arrival at the emergency department. There were no other symptoms. The dyspnea occurred about 5 h after being discharged on observation, with an uneventful postoperative course. Her electrocardiogram and chest X-ray findings were unremarkable. On testing, troponin I and creatine kinase myocardial band levels were elevated at 6.122 ng/mL and 11.2 µg/L (reference ranges: 0.000–0.046 ng/mL and 0.0–5.0 µg/L), respectively. Bedside echocardiography revealed an ejection fraction of 25%, with mid-ventricular and apical akinesia and basal hyperkinesia. The pulmonary and coronary angiographic computed tomographic scans were unremarkable. Hence, apical Takotsubo syndrome was suspected. A follow-up echocardiogram taken 5 days after admission showed full recovery with a normalized ejection fraction (60%) and no regional wall motion abnormality. The patient was discharged on the sixth day with no other complications. Conclusion When atypical symptoms, such as transient dyspnea, manifest, it becomes necessary to suspect and diagnose Takotsubo syndrome to ensure timely and appropriate medical management, especially when a preceding stressful event, such as minor surgery has occurred. It might be helpful to perform bedside point-of-care echocardiography to check for regional wall motion abnormalities that are typically associated with Takotsubo syndrome.

Objective Bilateral frozen shoulder (FS) is often treated with intra-articular corticosteroid injection (IACI). No studies have been performed to establish whether IACI must be administered in both shoulders or in only one shoulder to improve function. This study was therefore performed to determine whether unilateral IACI improves shoulder pain and passive range of motion (pROM) in bilateral FS. Methods The medical records of 165 patients with bilateral primary FS who underwent ultrasonography-guided IACI (2 mL of 10-mg/mL triamcinolone acetonide mixed with 5 mL of 1% lidocaine) in one shoulder were retrospectively reviewed. The outcome measures, namely the numeric rating scale (NRS) scores and pROM values (abduction, external rotation, flexion, hyperextension, and internal rotation), were evaluated pre- and post-injection. Results The patients’ mean age was 54.0 ± 8.0 years. The mean symptom duration was 6.5 ± 2.8 months. The mean follow-up period after injection was 6.7 ± 0.8 weeks. The NRS scores and pROM values significantly improved in both the injected and non-injected shoulders. Conclusions This study showed that unilateral IACI in patients with bilateral FS improves the clinical outcome of the non-injected shoulder. We suggest that physicians observe the non-injected shoulder after unilateral injection rather than performing bilateral injections.

A shape detail transfer is the process of extracting the geometric details of a source region and transferring it onto a target region. In this paper, we present a simple and effective method, called GeoStamp, for transferring shape details using a Poisson equation. First, the mean curvature field on a source region is computed by using the Laplace–Beltrami operator and is defined as the shape details of the source region. Subsequently, the source and target regions are parameterized on a common 2D domain, and a mean curvature field on the target region is interpolated by the correspondence between two regions. Finally, we solve the Poisson equation using the interpolated mean curvature field and the Laplacian matrix of the target region. Consequently, the mean curvature field of the target region is replaced with that of the source region, which results in the transfer of shape details from the source region to the target region. We demonstrate the effectiveness of our technique by showing several examples and also show that our method is quite useful for adding shape details to a surface patch filling a hole in a triangular mesh.

Curves on a polygonal mesh are quite useful for geometric modeling and processing such as mesh-cutting and segmentation. In this paper, an effective method for constructing C1 piecewise cubic curves on a triangular mesh M while interpolating the given mesh points is presented. The conventional Hermite interpolation method is extended such that the generated curve lies on M. For this, a geodesic vector is defined as a straightest geodesic with symmetric property on edge intersections and mesh vertices, and the related geodesic operations between points and vectors on M are defined. By combining cubic Hermite interpolation and newly devised geodesic operations, a geodesic Hermite spline curve is constructed on a triangular mesh. The method follows the basic steps of the conventional Hermite interpolation process, except that the operations between the points and vectors are replaced with the geodesic. The effectiveness of the method is demonstrated by designing several sophisticated curves on triangular meshes and applying them to various applications, such as mesh-cutting, segmentation, and simulation.

A triangular mesh obtained by scanning 3D models typically contains holes. We present an effective technique for filling a hole in a triangular mesh in geometric modeling. Simple triangulation of a hole is refined and remeshed iteratively to generate an initial patch. The generated patch is then enhanced to become a target patch by minimizing the variation of principal curvatures. In discrete approximation, this produces a third-order Laplacian system of sparse symmetric positive definite matrix, and the symmetry can efficiently be used to find the robust solutions to the given Laplacian system. Laplacian smoothing of the target patch is defined as a source patch. The shape difference between two corresponding vertices of the source and the target patches is measured in terms of Euclidean distance and curvature variation. On the basis of the shape difference and a user-specified control parameter, different blending weights are determined for each vertex, and the final patch is generated by blending two patches. We demonstrate the effectiveness of our technique by discussing several examples. The experimental results show that our technique can effectively restore salient geometric features of the original shape.

Purpose: To demonstrate the superficial hyperechoic band (SHEB) in articular cartilage by using ultrasonography (US) and to assess its correlation with histological images. Methods: In total, 47 regions of interest (ROIs) were analyzed from six tibial osteochondral specimens (OCSs) that were obtained after total knee arthroplasty. Ultrasonograms were obtained for each OCS. Then, matching histological sections from all specimens were obtained for comparison with the ultrasonograms. Two types of histological staining were used: Safranin-O stain (SO) to identify glycosaminoglycans (GAG) and Masson’s trichrome stain (MT) to identify collagen. In step 1, two observers evaluated whether there was an SHEB in each ROI. In step 2, the two observers evaluated which histological staining method correlated better with the SHEB by using the ImageJ software. Results: In step 1 of the analysis, 20 out of 47 ROIs showed an SHEB (42.6%, kappa=0.579). Step 2 showed that the SHEB correlated significantly better with the topographical variation in stainability in SO staining, indicating the GAG distribution, than with MT staining, indicating the collagen distribution (P

We present a new method for constructing a parametric blending surface that smoothly connects two triangular meshes. A user selects a subregion on each triangular mesh. The local parameterizations of two selected regions are found by using geodesic polar coordinates, and a base surface on each triangular mesh is constructed by two boundary curves on parametric domain. Finally, two base surfaces are smoothly blended for generating a blending surface. The shape of a blending surface can easily be controlled by several shape parameters or by directly manipulating surface point. We demonstrate the effectiveness of our technique by showing several modeling examples.

We propose a new tangible visualization table for intuitive and effective visualization of terrain data transferred from a remote server in real time. The shape display approximating the height field of remote terrain data is generated by linear actuators, and the corresponding texture image is projected onto the shape display. To minimize projection distortions, we present a sophisticated technique for projection mapping. Gesture-based user interfaces facilitate intuitive manipulations of visualization results. We demonstrate the effectiveness of our system by displaying and manipulating various terrain data using gesture-based interfaces.

We facilitate the editing of hierarchical B-spline curves at multiple resolutions by expressing a displacement function at each level in rotation minimizing frames (RMFs) on the curve at the next lower level. When the curve is edited at a particular level, RMFs at all the higher levels are updated, and the control points of the displacement function at each higher level are obtained from these new RMFs. This transfers details created at the current level to higher levels. Our method presents a hundred-fold faster way to reflect editing results compared to the traditional approach using Frenet frames. We demonstrate the effectiveness of our technique by showing several examples of editing curves with fine details.

An efficient surface area evaluation method is introduced by using smooth surface reconstruction for three-dimensional scanned human body data. Surface area evaluations for various body parts are compared with the results from the traditional alginate-based method, and quite high similarity between the two results is obtained. We expect that our surface area evaluation method can be an alternative to measuring surface area by the cumbersome alginate method.

PN (point-normal) triangles are cubic Bézier triangles which meet at their edges to surface a triangular mesh, but this only achieves G0 continuity. We define blending regions that span the edges shared by adjacent pairs of triangular domains and blend the corresponding Bézier triangles using a univariate blending function formulated in terms of barycentric coordinates. This produces G2 continuity across boundaries while preserving G1 continuity at vertices. The sharpness of the blends can be controlled locally by varying the extent of these blending regions. We demonstrate the effectiveness of our technique by showing several modeling examples.