• Restorative Dentistry and Endodontics
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• v.45 no.1
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• pp.1.1-1.9
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• 2020

Objectives: The purpose of this study was to determine the incidence of radix molaris (RM) (entomolaris and paramolaris) in the mandibular first permanent molars of a sample Saudi Arabian subpopulation using cone-beam computed tomography (CBCT). Materials and Methods: A total of 884 CBCT images of 427 male and 457 female Saudi citizens (age 16 to 70 years) were collected from the radiology department archives of 4 dental centers. A total of 450 CBCT images of 741 mature mandibular first molars that met the inclusion criteria were reviewed. The images were viewed at high resolution by 3 examiners and were analyzed with Planmeca Romexis software (version 5.2). Results: Thirty-three (4.5%) mandibular first permanent molars had RM, mostly on the distal side. The incidence of radix entomolaris (EM) was 4.3%, while that of radix paramolaris was 0.3%. The RM roots had one canal and occurred more unilaterally. No significant difference in root configuration was found between males and females (p > 0.05). Types I and III EM root canal configurations were most common, while type B was the only RP configuration observed. Conclusions: The incidence of RM in the mandibular first molars of this Saudi subpopulation was 4.5%. Identification of the supernumerary root can avoid missing the canal associated with the root during root canal treatment.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.29-36
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• 2016

Objectives: The purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA). Materials and Methods: Eighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP). Results: On micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP. Conclusions: Our results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA.

• The Journal of the Korean dental association
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• v.56 no.2
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• pp.84-93
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• 2018

Purpose: This study evaluated the apical root canal system of maxillary second molars, in which conventional endodontic treatment had failed. Materials and Methods: One hundred eighteen extracted endodontically failed maxillary second molars were examined to investigate the root canal morphology using clinical photographs. High-resolution cross-sectional images at the 3mm level from the root apices were taken to evaluate the anatomic variations and canal cleanliness. The incidence of anatomic variations and canals containing debris were evaluated statistically. Results: One (0.85%) maxillary second molar had four separate roots, while 52 (44.07%) had three separate roots. The remaining 65 (55.08%) showed 6 different types of fusion in their roots. As the number of fused roots increased from none to three, the incidence of isthmuses in the cross-sectional images increased significantly from 43.40% to 76.92% in 2-root fusion and 88.46% in 3-root fusion. In addition, the occurrence of less-cleansed canals increased from 22.64% to 38.46% and 53.85%, respectively (p<0.05). Sixty four teeth (54.24%) had 3 canals while 38(32.2%) had additional canals; most of them were located in the MB roots (81.58%). Seventy six (64.41%) had isthmuses in the apical region and 58 out of 76 were located in MB roots. Condlusions: Logistic analysis indicated that the less division of roots was associated significantly with the occurrence of insufficient cleaning during endodontic treatment (OR=1.765, p<0.05), while the presence of an additional canal showed no association.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1122-1127
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• 2007

We propose the complexity reduction algorithm of real root method that is mainly used in the Vocoder. The real root method is that if polynomial equations have the real roots, we are able to find those and transform them into LSP(Line Spectrum Pairs). However, this method takes much time to compute, because the root searching is processed sequentially in frequency region. The important characteristic of LSP is that most of coefficients are occurred in specific frequency region. So, the searching frequency region is ordered and adjusted by each coefficient's distribution in this paper. Transformation time can be reduced by proposed algorithm than the sequential searching method in frequency region. When we compare this proposed method with the conventional real root method, the experimental result is that the searching time was reduced about 48% in average.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.156-162
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• 2021

Background: It is estimated that 20-30% of ginseng crops in Canada are lost to root rot each harvest. This disease is commonly caused by fungal infection with Ilyonectria, previously known as Cylindrocarpon. Previous reports have linked the virulence of fungal disease to the production of siderophores, a class of small-molecule iron chelators. However, these siderophores have not been identified in Ilyonectria. Methods: High-resolution LC-MS/MS was used to screen Ilyonectria and Cylindrocarpon strain extracts for secondary metabolite production. These strains were also tested for their ability to cause root rot in American ginseng and categorized as virulent or avirulent. The differences in detected metabolites between the virulent and avirulent strains were compared with a focus on siderophores. Results: For the first time, a siderophore N,N',N"-triacetylfusarinine C (TAFC) has been identified in Ilyonectria, and it appears to be linked to disease virulence. Siderophore production was suppressed as the concentration of iron increased, which is in agreement with previous reports. Conclusion: The identification of the siderophore produced by Ilyonectria gives us further insight into the root rot disease that heavily affects ginseng crop yields. This research identifies a molecular pathway previously unknown for ginseng root rot and could lead to new disease treatment options.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.155-164
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• 2002

In this study, in order to discuss the geometric correction methods of high-resolution IKONOS satellite image, the existing polynomial model and RFM which is able to rectify satellite image without auxiliary data are applied to IKONOS satellite image data. Then the accuracy of ground point versus number of GCPs and each order of RFM are assessed. A numerical instability is removed by application of Tikhonov regularization method. As the results of this study, the root mean square errors of RFM is decreased more than 2 pixels in comparison with the two dimensional polynomial model.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.268-277
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• 2008

Authors evaluated 1171 patients at the department of Pediatric Dentistry in Kyoungpook National University Hospital through clinical records and radiographs. And the following features were studied ; age, sex distribution, number of mesiodens per patients, cause of discovery of mesiodens, location, status of eruption, shape and orientation of crown, complication, dental age of adjacent upper incisor tooth at the time of surgical extraction of mesiodens and the relationship between the resolution rate of complication after extraction of mesiodens and the dental age of adjacent upper incisor tooth, length of diastema, the eruption status of lateral incisor and the crowding status of premaxilla. The followings are the results : 1. The cause of discovery of mesiodens were as follows ; delayed eruption of the permanent incisors in 13.8%, midline diastema in 11.6%, radiographs taken for other reasons in 23.4% and for caries treatment in 15.1%. 2. Complication due to the presence of mesiodens did not occur in 36.8%, delayed eruption of adjacent teeth was observed in 16.1%, midline diastema in 34.4%, rotation in 8.8%, displacement in 2.4%, and crowding in 1.0% of all evaluated patients. 3. As for the dental age of adjacent upper incisor tooth at the time of surgical extraction of mesiodens, below 1/3 of total root length were observed in 3.5%, $1/3{\sim}1/2$ of total root length in 19.9%, $1/2{\sim}2/3$ of total root length in 54.7% and over 2/3 in 21.9% of all evaluated patients. 4. Resolution rate of delayed eruption after the extraction of mesiodens was significant higher in the group with the root length below 1/2. Resolution rate of midline diastema was significant higher in the group with diastema width below 3mm and with non-crowding of adjacent upper incisor teeth.

• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.48-53
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• 2010

Water-uptake through roots, is an essential process of the water flow in plants. Its visualization is very useful for understanding sap flow dynamics at whole plant level. In this study, the tips of Arabidopsis' root hairs were excised and exposed to repeated dehydration and rehydration processes. The water-refilling through individual xylem vessels was visualized using the synchrotron X-ray micro-imaging technique. The high temporal resolution ($2\;{\mu}m$) and beam intensity of the X-ray source allowed to acquisition of consecutive X-ray images of the water-refilling process up to 10 frames/sec. Various flow patterns were observed and the ascending speed of the water-air interfaces was analyzed. The relation between the water-rising height and ascending speed was also analyzed. The present results would provide better alternative for investigating sap flows in roots.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.422-431
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• 2003

Helicopter-borne electromagnetic (HEM) systems were originally developed for the exploration of mineral deposits. The frequency range of a conventional HEM system for mineral exploration, however, is relatively low and so not invariably suitable for its application to the fields of civil engineering because of its poor resolution in the shallower part of the earth. A DIGHEM HEM system was acquired by Nippon Engineering, with the frequencies chosen by the senior author. The five frequencies range from 220 Hz (the lowest) to 137,500 Hz (the highest). These frequencies improve the resolution of materials in the shallower part while maintaining a depth of investigation of greater than 100 m. This paper describes six case histories of geological and geotechnical surveys for civil engineering using HEM. These case histories include HEM surveys for investigating landslide, an alluvial area, root selection of road construction, areas related to dam and tunnel construction, and the simultaneous joint inversion of HEM and CSAMT data for a deep tunnel. These survey results show that HEM has sufficient resolution in both horizontal and vertical directins to contribute significantly to outlining the regional geology and its engineering problems.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.571-581
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• 2015

Soil moisture content is generally accepted as an important factor to understand the process of crop growth and is the basis of earth system models for analysis and prediction of the crop condition. To continuously monitor soil moisture changes at kilometer scale, it is demanded to create high resolution data from the current, several tens of kilometers. In this paper we described a downscaling method for Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) from 10 km to 30 m resolution using a soil texture and field measurements that have a high correlation with the SMC. As a result, the soil moisture variations of both data (before and after downscaling) were identical, and the Root Mean Square Error (RMSE) of SMC exhibited the low values. Also, time series analyses showed that three kinds of SMC data (field measurement, original AMSR2, and downscaled AMSR2) had very similar temporal variations. Our method can be applied to downscaling of other soil variables and can contribute to monitoring small-scale changes of soil moisture by providing high resolution data.