• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.485-490
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• 2003

Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.95-103
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• 1992

The purpose of this study was to evaluate the effect of the dentin pretreatment on the marginal leakage of a glassionomer cement. 1n this study, 60 molars with sound and healthy crown portion were used. The dentin surface of these teeth were exposed and polished with 600 grit silicon carbide paper. Square - shaped cavities were prepared on the flattened dentin surfaces and these were divided into 4 groups according to the dentin pretreatment procedures. Group I : Dentin pretreatment with distilled water as a control group. Group II : Dentin pretreatment with 5% sodium hypochlorite solution. Group III : Dentin pretreatment with Ketac conditioner. Group IV : Dentin pretreatment with 40% polyacrylic acid. The degrees of dye penetration in the cavity walls were assessed using a stereoscope at ${\times}40$ magnification according to the maximum dye penetration. The results were analyzed by using Mann - Whitney U test. The results were as follows : 1. All groups showed varying depth of dye penetration. 2. Distilled water group showed the most severe marginal leakage when compared with the other groups(P<0.05). 3. 40% polyacrylic acid group showed the least amount of marginal leakage compared with the other groups (P<0.05). 4. There were significant differences between Goup I(distilled water) and Group IV (40% polyacrylic acid)(P<0.05), but there were no significant differences among Group I(distilled water), Group II(sodium hypochlorite), Group III(Ketac conditioner) (P>0.05).

• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.200-205
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• 2017

Objectives: The aim of this in vivo study was to assess the accuracy of 2 third-generation electronic apex locators (EALs), Propex II (Dentsply Maillefer) and Root ZX II (J. Morita), and radiographic technique for locating the major foramen (MF). Materials and Methods: Thirty-two premolars with single canals that required extraction were included. Following anesthesia, access, and initial canal preparation with size 10 and 15 K-flex files and SX and S1 rotary ProTaper files, the canals were irrigated with 2.5% sodium hypochlorite. The length of the root canal was verified 3 times for each tooth using the 2 apex locators and once using the radiographic technique. Teeth were extracted and the actual WL was determined using size 15 K-files under a ${\times}25$ magnification. The Biostat 4.0 program (AnalystSoft Inc.) was used for comparing the direct measurements with those obtained using radiographic technique and the apex locators. Pearson's correlation analysis and analysis of variance (ANOVA) were used for statistical analyses. Results: The measurements obtained using the visual method exhibited the strongest correlation with Root ZX II (r = 0.94), followed by Propex II (r = 0.90) and Ingle's technique (r = 0.81; p < 0.001). Descriptive statistics using ANOVA (Tukey's post hoc test) revealed significant differences between the radiographic measurements and both EALs measurements (p < 0.05). Conclusions: Both EALs presented similar accuracy that was higher than that of the radiographic measurements obtained with Ingle's technique. Our results suggest that the use of these EALs for MF location is more accurate than the use of radiographic measurements.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.274-277
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• 2007

Purpose: Microsuturing is a difficult job for beginners of microsurgery. It is because they are not familiar with microscopic environment and, it needs much time for them to get used to microanastomosis. Before the real microsurgery, sometimes a surgeon wants rehearsal. But, microsurgical exercise has been performed with surgical glove, silastic drain or rat femoral artery. Rat femoral artery is a very good training material. But, it needs animal laboratory, anesthesia and its keeping facilities. And the surgeon should appoint the time to exercise with the laboratory. Methods: We used chicken wing brachial artery for education material of microsuturing. The artery is 5 cm long and the diameter is about 1 mm. Monofilament 10-0 was used for suture material. Results: Six persons of Seoul National University medical school students and one resident attended in this program. Each of them performed arterial anastomosis ten times. They were satisfied with chicken wing brachial artery for anastomosis training under the magnification environment. Conclusion: We think that chicken wing brachial artery is a very cheap and an effective training material for the beginners of microsurgery.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.642-648
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• 2011

Purpose: The recent advances in microsurgical techniques and their refinement over the past decade have greatly expanded the indications for digital replantations and have enabled us to salvage severed fingers more often. Many studies have reported greater than 80% viability rates in replantation surgery with functional results. However, replantation of multi-level amputations still remain a challenging problem and the decision of whether or not to replant an amputated part is difficult even for an experienced reconstructive surgeon because the ultimate functional result is unpredictable. Methods: Between January of 2002 and May of 2008, we treated 10 multi-level amputated digits of 7 patients. After brachial plexus block, meticulous replantation procedure was performed under microscopic magnification. Postoperatively, hand elevation, heat lamp, drug therapy and hyperbaric oxygen therapy were applied with careful observation of digital circulation. Early rehabilitation protocol was performed for functional improvement. Results: Among the 19 amputated segments of 10 digits, 16 segments survived completely without any complications. Overall survival rate was 84%. Complete necrosis of one finger tip segment and partial necrosis of two distal amputated segments developed and subsequent surgical interventions such as groin flap, local advancement flap and skin graft were performed. The overall result was functionally and aesthetically satisfactory. Conclusion: We experienced successful replantations of multi-level amputated digits. When we encounter a multi-level amputation, the key question is whether or not it is a contraindication to replantation. Despite the demand for skillful microsurgical technique and longer operative time, the authors' results prove it is worth attempting replantations in multi-level amputation because of the superiority in aesthetic and functional results.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.179-181
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• 1986

Computed tomography (CT) adds a new dimension in the study of body contour, organs, and tissues as well as various pathologic conditions. This modality provides a great degree of accuracy in radiation therapy Planning (RTP). However, CT images are usually taken on a small reduced format so that possible errors can be made during inputting the CT data into an automatic planner. Authors have designed a simple inexpensive magnifying device of CT images to obviate errors created by reduced image.

• Journal of the Korean Society of Radiology
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• v.4 no.1
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• pp.19-24
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• 2010

A cone-beam computed tomography (CT) system for a small animal has been widely used in the bio-medical application. This paper introduced simple methods for evaluating a cone-beam CT system using a simple tungsten wire phantom of 10{$\mu}m$ diameter and a water phantom. Slice images and three-dimensional tomography images were obtained through 360 projection views per one sample rotation under stable X-ray tube conditions for a long running time. The cone-beam CT system at a position of a 1.07 magnification showed a spatial frequency of 13.78 lp/mm ($36.2{\mu}m$ spatial resolution) and gave a CNR of 10.33 and a S/N of 5.87 under a tube voltage of 80kV.

• Laser Solutions
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• v.6 no.3
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• pp.19-28
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• 2003

The manufacturing process for the microfluidic device can include sequential steps such as master fabrication, electroforming, and injection molding. The laser ablation, using masks, has been applied to the fabrication of channels in microfluidic devices. In this research, an excimer laser was used to engrave microscopic channels on the surface of PET (polyethylene terephthalate), which shows a high absorption ratio for an excimer laser beam with a wavelength of 248 m. When 50-${\mu}{\textrm}{m}$-wide rectangular microscopic channels are ablated with a 500 ${\times}$ 500 ${\mu}{\textrm}{m}$ square mask at a magnification ratio of 1/10, ditch-shaped defects were found in both corners. The measurement of laser beam intensity showed that a coherent image in the PET target caused such defects. Analysis based on the Fourier diffraction theory enabled the prediction of the coherent shape at the image surface as well as the diffraction beam shape between the mask and the image surface. It also showed that the diameter of the aperture had a dominant effect. The application of aperture with a diameter of less than 3 mm helped to eliminate such defects in the ablated rectangular microscopic channels on PET without such ditch-shaped defects.

• Journal of Fashion Business
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• v.6 no.4
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• pp.32-45
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• 2002

The purpose of this study is, to renew understanding the aesthetic value of a ruff collar and to expand the border of creation in designing as the source of inspiration being applied to an retro style by inquiring various ruff collars re-illuminated in the present-day fashion trend. The ruff collar investigated through the above historical contemplation became the source of inspirations in the current retro trend and was variously modified in modern fashion. In the 1980s, we can find a dignified and feminine image in graceful and exquisite suits or dresses. Especially, the spanish round ruff of the 2st period appeared on works by a lot of designers. From the application by designers like John Galliano in the latter half of the 80s, we can be well aware that the meaning of decoration was newly altered. In the 1990s, the ruff collar was shown in various fashion style, but it was what was reborn as a factor of modern fashion through a liberal compromise and harmony. Various style was shown from exaggeratedly swelling one to smaller one, which were more diversely applied than that of the 80s. A Medici collar and a Queen Elizabeth collar were also displayed being fitted to a modern sense by Vivienne Westwood and Louis F raud. A ruff in the 2000s was settled as a factor of modern fashion, exposing on works of designers more often than in the 1980s and 90s. The spanish round ruff appeared on garments, while a Medici collar and a Queen Elizabeth collar went out of sight. A new form of the ruff was regenerated by extreme magnification and simplification, and several designers like Issey Miyake and Alexander Mcqueen brought forward a new way in materials and technical skills. According to this research, a ruff collar developed as a fashion factor which characterizes a certain period of time, reflecting the aesthetical sense of Renaissance and turning into various and distinct forms. Afterwards, it exerted influence on modern fashion. This is offering the source of inspiration to contemporary designers.

• KIISE Transactions on Computing Practices
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• v.21 no.9
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• pp.610-615
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• 2015

The accuracy and precision of video-based remote gaze trackers is affected by numerous factors (e.g. the head movement of the participant). However, it is challenging to control all factors that have an influence, and doing so (e.g., using a chin-rest to control geometry) could lead to losing the benefit of using gaze trackers, i.e., the ecological validity of their unobtrusive nature. We propose an adaptive zoom-based gaze tracking technique, ZoomTrack that addresses this problem by improving the resolution of the gaze tracking results. Our approach magnifies a region-of-interest (ROI) and retrieves gaze points at a higher resolution under two different zooming modes: only when the gaze reaches the ROI (temporary) or whenever a participant stares at the stimuli (omnipresent). We compared these against the base case without magnification in a user study. The results are then used to summarize the advantages and limitations of our technique.