• The korean journal of orthodontics
• /
• v.46 no.4
• /
• pp.189-198
• /
• 2016

Objective: The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods: We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results: Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions: For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone.

• Physical Therapy Rehabilitation Science
• /
• v.7 no.3
• /
• pp.95-101
• /
• 2018

Objective: To determine if the provision of visual biofeedback using real-time rehabilitative ultrasound imaging (RUSI) enhances the acquisition and retention of diaphragm muscle recruitment during exercise. Design: Two group pretest posttest design. Methods: Thirty healthy subjects were randomly assigned to the verbal feedback group (VG, n=15) or the visual and verbal feedback group (VVG, n=15). The VG performed breathing exercises 10 times with verbal feedback, and the VVG also performed breathing exercises 10 times with verbal feedback and visual feedback with the use of RUSI to measure changes in diaphragm thickness (DT). For DT, the mid-axillary lines between ribs 8 and 9 on both sides were measured in standing, and then the chest wall was perpendicularly illuminated using a linear transducer with the patients in supine to observe the region between rib 8 and 9 and to obtain 2-dimensional images. DT was measured as the distance between the two parallel lines that appeared bright in the middle of the pleura and the peritoneum. After one week, three repetitions (follow-up session) were performed to confirm retention effects. Intra- and between- group percent changes in diaphragm muscle thickness were assessed. Results: In the VVG, the intervention value had a medium effect size compared to the baseline value, but the follow-up value decreased to a small effect size. In the between-group comparisons, during the intervention session, the VVG showed no significant effect on percent change of DT but had a medium effect size compared to the VG (p=0.050, Cohen's d=0.764). During the follow-up session, retention effect did not persist (p=0.311, Cohen's d=0.381). Conclusions: RUSI can be used to provide visual biofeedback and improve performance and retention in the ability to activate the diaphragm muscle in healthy subjects. Future research needs to establish a protocol for respiratory intervention to maintain the effect of diaphragmatic breathing training using RUSI with visual feedback.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.8
• /
• pp.64-71
• /
• 2004

A computational study on the supersonic flow around the lateral jet controlled missile has been performed. For this purpose a three dimensional Navier-Stokes computer code(AADL3D) has been developed and case studies have been performed by comparing the normal force coefficient and the moment coefficient of a missile body for different jet flow conditions including jet pressure and jet Mach number. The results show different behavior of normal force and moment variation according to jet pressure variation and jet Mach number variation. From the detailed flow field analyses, it is verified that most of the normal force loss and the pitching moment generation are taken place at the low-pressure region behind the jet nozzle. Furthermore, it is shown that the pitching moment can be efficiently reduced by obtaining the lateral thrust through higher jet Mach number rather than through high jet pressure.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.11
• /
• pp.1154-1166
• /
• 1991

Optical flow is important not only for determining velocity and trajectory of the object but also for image segmentation and three dimensional information. In this paper an algorithm for segmentation of the optical flow field is presented. This method is based on a pyramid linking method combined with the proposed models. In this method each node contained a model of the flow in the region that it represented regions were combined by taking the model that best fit the union of the two regions. Each node linked to one of its fathers based on the error between the pixels represented by the node and the father's model of its flow. A major problem which has emerged in conventional researchs on optical flow field is sensitive to noise the proposed method is relatively insensitive to noise at the result of computer simulation the pyramid algorithm proposed in this paper seem to have useful properties.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.6
• /
• pp.9-21
• /
• 2016

Agricultural reservoirs in Korea have been recognized as an emerging resource for recreational and cultural activities for residents. However, most of the reservoirs are eutrophic and showing high level of contamination with nuisance algal bloom and offensive odor during the summer. For better management and restoration of the reservoirs' water quality, scientific modeling approaches could be used to diagnose the problems and evaluate the efficacy of alternative control measures. The objectives of this study were to validate the performance of a three-dimensional (3D) hydrodynamic and water quality model (Environmental Fluid Dynamics Code, EFDC) for a eutrophic agricultural reservoir and assess the effect of bypassing of the effluent from a wastewater treatment plant on the reservoir water quality. The 3D model successfully simulated the temporal variations of water temperature, DO, TOC, nitrogen and phosphorus species and Chl-a observed in 2014 and also captured their spatial heterogeneity in the reservoir. The simulation results indicated that the point source bypassing may reduce the T-N and T-P concentrations of the reservoir by 6.6 ~ 8.2 %, and 1.7 ~ 16.8 %, respectively. The bypassing, however, showed a marginal effect on the control of TOC due to the increased algal biomass associated with the increased water retention time after bypassing as well as the lower TOC level of the effluent compared to the ambient reservoir water.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.11
• /
• pp.1830-1840
• /
• 2019

Loliolide is one of the most ubiquitous monoterpenoid compounds found in algae, and its potential therapeutic effect on various dermatological conditions via agent-induced biological functions, including anti-oxidative and anti-apoptotic properties, was demonstrated. Here, we investigated the effects of loliolide on hair growth in dermal papilla (DP) cells, the main components regulating hair growth and loss conditions. For this purpose, we used a three-dimensional (3D) DP spheroid model that mimics the in vivo hair follicle system. Biochemical assays showed that low doses of loliolide increased the viability and size of 3D DP spheroids in a dose-dependent manner. This result correlated with increases in expression levels of hair growth-related autocrine factors including VEGF, IGF-1, and KGF. Immunoblotting and luciferase-reporter assays further revealed that loliolide induced AKT phosphorylation, and this effect led to stabilization of β-catenin, which plays a crucial role in the hair-inductive properties of DP cells. Further experiments showed that loliolide increased the expression levels of the DP signature genes, ALP, BMP2, VCAN, and HEY1. Furthermore, conditioned media from loliolide-treated DP spheroids significantly enhanced proliferation and the expression of hair growth regulatory genes in keratinocytes. These results suggested that loliolide could function in the hair growth inductivity of DP cells via the AKT/β-catenin signaling pathway.

• The korean journal of orthodontics
• /
• v.48 no.2
• /
• pp.81-89
• /
• 2018

Objective: The aim of this study was to evaluate the stress distribution and displacement of various craniofacial structures after nonsurgical rapid palatal expansion (RPE) with conventional (C-RPE), bone-borne (B-RPE), and miniscrew-assisted (MARPE) expanders for young adults using three-dimensional finite element analysis (3D FEA). Methods: Conventional, bone-borne, and miniscrew-assisted palatal expanders were designed to simulate expansion in a 3D FE model created from a 20-year-old human dry skull. Stress distribution and the displacement pattern for each circumaxillary suture and anchor tooth were calculated. Results: The results showed that C-RPE induced the greatest stress along the frontal process of the maxilla and around the anchor teeth, followed by the suture area, whereas B-RPE generated the greatest stress around the miniscrew, although the area was limited within the suture. Compared with the other appliances, MARPE caused relatively even stress distribution, decreased the stress on the buccal plate of the anchor teeth, and reduced tipping of the anchor teeth. Conclusions: The findings of this study suggest that the incorporation of miniscrews in RPE devices may contribute to force delivery to the sutures and a decrease in excessive stress on the buccal plate. Thus, MARPE may serve as an effective modality for the nonsurgical treatment of transverse maxillary deficiency in young adults.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.4
• /
• pp.265-270
• /
• 2018

PURPOSE. The purpose of this in vitro study was to evaluate the accuracy of a new implant impression technique using bite impression coping and a dual arch tray. MATERIALS AND METHODS. Two implant fixtures were placed on maxillary left second premolar and first molar area in dentoform model. The model with two fixtures was used as the reference. The impression was divided into 2 groups, n=10 each. In group 1, heavy/light body silicone impression was made with pick up impression copings and open tray. In group 2, putty/light body silicone impression was made with bite impression copings and dual arch tray. The reference model and the master casts with implant scan bodies were scanned by a laboratory scanner. Surface tessellation language (STL) datasets from test groups was superimposed with STL dataset of reference model using inspection software. The three-dimensional deviation between the reference model and impression models was calculated and illustrated as a color-map. Data was analyzed by independent samples T-test of variance at ${\alpha}=.05$. RESULTS. The mean 3D implant deviations of pick up impression group (group 1) and dual arch impression group (group 2) were 0.029 mm and 0.034 mm, respectively. The difference in 3D deviations between groups 1 and 2 was not statistically significant (P=.075). CONCLUSION. Within limitations of this study, the accuracy of implant impression using a bite impression coping and dual arch tray is comparable to that of conventional pick-up impression.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.15
• /
• pp.6595-6597
• /
• 2015

Objective: To investigate short- and long-term treatment effects and side reactions of lobaplatin plus 5-Fu combined and concurrent radiotherapy in treating patients with inoperable middle-advanced stage esophageal cancer. Methods: Sixty patients with middle-advanced stage esophageal squamous cell cancer were retrospectively analyzed. All patients were administered lobaplatin (50 mg intravenously) for 2 h on day 1, and 5-Fu ($500mg/m^2$) injected intravenously from day 1 to 5 for 1 cycle, in an interval of 21 days for totally 4 cycles. At the same time, late-course accelerated hyperfractionated three-dimensional conformal radiotherapy was performed. Patients were firstly treated with conventional fractionated irradiation (1.8 Gy/d, 5 times/week, a total of 23 treatments, and DT41.4 Gy), and then treated with accelerated hyperfractionated irradiation (1.5 Gy, 2 times/d, a total of 27 Gy in 9 days, an entire course of 6-7 weeks, and DT 68.4Gy). Results: All patients completed treatment, including 10 complete response (CR), 41 partial response (PR), 7 stable disease (SD), and 2 progressive disease (PD). The total effective rate was 85.0% (51/60). Thirty-nine patients had an increased KPS score. One-, 2-, and 3-year survival rates were 85.3%, 57.5%, and 41.7%, respectively. The median survival time was 27 months. The adverse reactions included myelosuppression, which was mainly degree I and II. The occurrence rate of radiation esophagitis was 17.5%. No significant hepatic or renal toxicity was observed. Conclusion: Lobaplatin plus 5-Fu combined with concurrent radiotherapy is safe and effective in treating patients with middle-advanced stage esophageal cancer. However, this result warrants further evaluation by randomized clinical studies.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.4
• /
• pp.153-159
• /
• 2012

For the construction of safe and clear urban environment, it is necessary that we identify the rubbish waste volume and we know the accuracy volume. In this paper, we proposed the algorithm computes the waste volume periodically for the way of waste repository standard. After stereo camera calibration, we obtained the point cloud on the surface of the object and took this as the input of the calculation algorithm of the object volume. We proposed the volume calculation algorithms based on the non-uniform triangular meshing methods and verified the validity of the algorithm through simulation and real experiments. The proposed algorithm can be used not only as the volume calculation of the waste repository but also as the general volume calculation of a three dimensional object.