• Economic and Environmental Geology
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• v.45 no.4
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• pp.377-384
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• 2012

The main field component of the Earth's magnetic field was modeled from the tri-axial magnetometer onboard KOrean MultiPurpose SATellite-II (KOMPSAT-II) for the purpose of satellite attitude control. The model computed by the KOMPSAT-II magnetometer measurement data is compared with the International Geomagnetic Reference Field (IGRF) model of a degree of up to 13 in spherical harmonic coefficients. The previous study with KOMPSAT-I (Kim et al. 2004) indicated a good correlation of power spectrum of spherical harmonic coefficients with respect to the degree up to 5. This study, however, showed an agreement of the degree up to 8-9 of the coefficient power spectrum and a discrepancy between degrees 10 and 13. We have concluded that relevant data selection process, removal of the external field from the data in the high latitude region, an accuracy of the magnetometer all play an important role in finding a coherence with the IGRF model. This study will be extended to the secular variation model of geomagnetism if longer-period data become available.

• Journal of Conservation Science
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• v.34 no.3
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• pp.179-193
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• 2018

This study is aimed to investigate the provenance of raw materials and firing temperature of jar coffins excavated from the Oryang-dong kiln site and Jeonchon tomb site, Naju, Korea. Most of jar coffin samples shows same range of magnetic susceptibility and have gray color, while 404 and 405 of Jeongchon site are reddish yellow. In some samples fired at high temperature, the water absorption at the mouth rim and body part of same jar coffin were 3.50% and 7.56% respectively. It means that heat transfer and equilibrium in the kiln was not properly continued and the heat energy transferred to the mouth rim and the body part was different. In the petrographic analysis, As a tempering materials, biotite, weathered quartz and feldspar were added in the jar coffins of Oryang-dong site, and biotite, polycrystalline quartz and feldspar in it of Jeongchon site. Tempering materials were found more in the body than in the mouth rim of same jar coffin of Oryang-dong site. It seemed that some samples were fired at over 1,000 to $1,100^{\circ}C$, which showed vitrified texture in the scanning electron images and the rest of samples were fired at below $900^{\circ}C$. Due to similarity of chemical compositions, it is estimated that jar coffins of Jeongchon tomb were produced and supplied from Oryang-dong kiln site. However, the slight difference of some trace elements distribution of samples is attributed to the selection of clay depending on the location.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.403-410
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• 2015

Since 1970, MRI has greatly been developing in terms of strength of magnetic field, the number of receipt channels, and short time of examination. With the development of digital systems and wireless network, hospitals have also acquired, saved, and managed digital images taken by various kinds of medical imaging equipment. However, domestic universities fail to provide practice training course independently thanks to expensive practice equipment and high maintenance cost, and rely on clinical training. Therefore, this study developed a MR patient diagnosis program based on Windows PC to help out students before their working in clinical filed. The designed Relational Database of MRI Simulator is made up of seven tables according to functions and data characteristics. Regarding the designed patient information, each stepwise function was classified by the patient registration method in clinical field. In addition, on the assumption of the basic information for diagnosis, each setting and content were classified. The menu by execution step was arrayed on the left side for easy view. For patient registration, a patient's name, gender, unique ID, birth date, weight, and other types of basic information were entered, and the patient's posture and diagnosis direction were set up. In addition, the body regions for diagnosis and Pulse Sequence were listed for selection. Also, Protocol name and other additional factors were allowed to be entered. The final window was designed to check diagnosis images, patient information, and diagnosis conditions. By learning how to enter patient information and change diagnosis conditions in this program, users will be able to understand more theories and terms learned in practice and thereby to shorten their learning time in actual clinical work.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.311-315
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• 2004

The brown planthopper, Nilaparvata lugens, is among the most serious insect pests of rice. It is widely distributed in Asia, Australia and Pacific islands. An earlier mitochondrial DNA study revealed that there exist significant genetic differences between populations north and south of the Red River Delta region in Vietnam. However the mitochondrial DNA was not sufficiently variable to examine the sources of immigration. For a more detailed analysis of geographic population structure of N. lugens, we developed microsatellite markers. Thirty-seven putative microsatellite loci were isolated using a magnetic biotin method, and five primer pairs designed from the flanking regions of sequenced microsatellite clones were labeled with fluorescent. Of these five primer sets, two have proven to be useful across all the samples we used in this study. We used variation at these two microsatellite loci to test the hypothesis that N. lugens biotypes (1, 2, and 3) sampled from laboratory selection constituted distinct genetic units. Allele frequency differences among the three major biotype categories were not significantly different at one locus (27035). However, the other (7314) did show differences among the major three biotypes. The methods we describe here will be useful for studying population structure of crop pest and for tracking the patterns of migratory pest like the rice planthoppers.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.637-645
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• 2017

The objective of this study was to find the optimum test device for the cerebral blood vessels by comparing and analyzing the SNR and CNR methods for images of three devices (i.e., MRA, CTA, and DSA). The study targeted 90 patients who underwent cerebral angiography from November 2016 to May 2017. The measuring parts were measured by using Rt MCA, Lt MCA, and ACA Image J. The results of quantitative analysis showed that the mean SNR of MRA, the CNR of MRA, the signal strength of MRA, the mean SNR of CTA, the CNR of CTA, the signal strength of CTA, the SNR of DSA, the CNR of DSA, and the signal strength of DSA were evaluated as 254.87, 178.13, 326.81, 74.75, 62.2, 356.66, 26.85, 25.89, and 4400.69, respectively (p<0.05). As a result, both SNR and CNR methods measured it in the order of MRA>CTA>DSA. Statistical significance was determined by using ANOVA analysis at p<0.05 and Bonferroni method was used as a post-hoc analysis SPSS. In conclusion, the results of this study revealed that the optimum imaging devices were MRA, CTA, and DSA after evaluating randomly selected patients with cerebrovascular disease.

• Journal of Gastric Cancer
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• v.20 no.1
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• pp.60-71
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• 2020

Purpose: The utility of 18-fluordesoxyglucose positron emission tomography ([¹⁸F]-FDG-PET) combined with computer tomography or magnetic resonance imaging (MRI) in gastric cancer remains controversial and a rationale for patient selection is desired. This study aims to establish a preclinical patient-derived xenograft (PDX) based [¹⁸F]-FDG-PET/MRI protocol for gastric cancer and compare different PDX models regarding tumor growth and FDG uptake. Materials and Methods: Female BALB/c nu/nu mice were implanted orthotopically and subcutaneously with gastric cancer PDX. [¹⁸F]-FDG-PET/MRI scanning protocol evaluation included different tumor sizes, FDG doses, scanning intervals, and organ-specific uptake. FDG avidity of similar PDX cases were compared between ortho- and heterotopic tumor implantation methods. Microscopic and immunohistochemical investigations were performed to confirm tumor growth and correlate the glycolysis markers glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) with FDG uptake. Results: Organ-specific uptake analysis showed specific FDG avidity of the tumor tissue. Standard scanning protocol was determined to include 150 μCi FDG injection dose and scanning after one hour. Comparison of heterotopic and orthotopic implanted mice revealed a long growth interval for orthotopic models with a high uptake in similar PDX tissues. The H-score of GLUT1 and HK2 expression in tumor cells correlated with the measured maximal standardized uptake value values (GLUT1: Pearson r=0.743, P=0.009; HK2: Pearson r=0.605, P=0.049). Conclusions: This preclinical gastric cancer PDX based [¹⁸F]-FDG-PET/MRI protocol reveals tumor specific FDG uptake and shows correlation to glucose metabolic proteins. Our findings provide a PET/MRI PDX model that can be applicable for translational gastric cancer research.

• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.323-330
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• 2016

Pinellia ternata Breitenbach, the natural medicinal plant of the Araceae family, is a perennial plant originated from the East Asia, but also widely distributed in Europe and North America. Its tuber is used as traditional medicine for treatment of various diseases such as vomiting, inflammation, and traumatic injury. Pharmacological studies revealed that P. ternata possesses anticonvulsant, anti-tumor, insecticidal, and cytotoxic activities. Despite being well-known as the useful medicinal plant, there is no reliable, standardized method for origin discrimination. Ultra performance liquid chromatography-photodiode array detector and quadrupole time of flight-mass spectrometry based metabolite-profiling was applied to explore significant metabolite for origin discrimination between Korean and Chinese P. ternata. One compound was isolated from Korean P. ternata using repeated ODS column chromatography by bioactivity guided fractionation, and determined as [6]-gingerol according to the results of spectroscopic data including nuclear magnetic resonance and MS. This compound was selected as cosmeceutical biomarker by fingerprints, and it was associated to melanin inhibitory effect determining its origin authenticity. Furthermore, the calibration curve of biomarker was prepared using validated method for the comparison of content between Korean and Chinese P. ternata. This is the report to address the selection and successful validation of the discriminant metabolite for confirmation of Korean P. ternata.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.337-346
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• 2006

Aims: The present study investigated the relationship between condylar resorption and craniofacial skeleton types(especially vertical relationships), the differences of craniofacial skeleton types between with open bite group and without open bite group, and the associations of anterior disc dislocation with or without reduction to condylar resorption with MRI. Patients selection and methods: Clinical examination, magnetic resonance imaging (MRI), panorama, lateral transcranial and lateral cephalometric radiographs in 34 patients with condylar resorption were used to investigate this relationship. Results and Conclusions: Patients with the following specific facial morphologic characteristics appear to be most susceptible to condylar resorption: (1) females were predominant, (2) patients' age ranged from 12 to 50 years old with a strong predominance for 2nd and 3rd decades, (3) patients had high mandibular plane angle and high gonial angle, (4) patients had decreased vertical height of the ramus, (5) patients had generally significant antegonial notch, (6) patients had predominance of Class I occlusal relationship with or without open bite but mandible was retruded as mean ANB 5.54 degrees, (7) condylar resorption rarely occurs in lower mandibular plane angle facial types, (8) although no statistically significant difference was found, the open bite group had a tendency more hyperdivergent skeletal pattern than the non open bite group, and (9) imaging demonstrates from small resorbing condyles to idiopathic condylar resorption and TMJ articular disc dislocations. Thus, morphologic features of patients with vertical discrepancies may represent a risk factor for the development of condylar resorption.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.225-234
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• 2009

Real-time Aerial Monitoring System (RAMS) is to perform the rapid mapping in an emergency situation so that the geoinformation such as orthophoto and/or Digital Elevation Model is constructed in near real time. In this system, the GPS/INS plays an very important role in providing the position as well as the attitude information. Therefore, in this study, the performance of an IMU sensor which is supposed to be installed on board the RAMS is evaluated. And the integration algorithm of GPS/INS are tested with simulated dataset to find out which is more appropriate in real time mapping. According to the static and kinematic results, the sensor shows the position error of 3$\sim$4m and 2$\sim$3m, respectively. Also, it was verified that the sensor performs better on the attitude when the magnetic field sensor are used in the Aerospace mode. In the comparison of EKF and UKF, the overall performances shows not much differences in straight as well as in curved trajectory. However, the calculation time in EKF was appeared about 25 times faster than that of UKF, thus EKF seems to be the better selection in RAMS.

• Journal of Korean Foot and Ankle Society
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• v.26 no.2
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• pp.95-102
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• 2022

Purpose: This study was based on the Korean Foot and Ankle Society (KFAS) member survey and aimed to report the current trends in the management of syndesmotic injuries over the last few decades. Materials and Methods: A web-based questionnaire containing 36 questions was sent to all KFAS members in September 2021. The questions were mainly related to the preferred techniques and clinical experiences in the treatment of patients with syndesmotic injuries. Answers with a prevalence ≥50% of respondents were considered a tendency. Results: Seventy-six (13.8%) of the 550 members responded to the survey. The results showed that the most preferred method to diagnose a syndesmotic injury was magnetic resonance imaging (MRI). Intraoperatively, the external rotation stress test and the Cotton test were most frequently used to confirm syndesmotic diastasis. The reduction was usually done by a reduction clamp. One 3.5-mm screw was used most frequently over three cortices at 2~4 cm above the ankle joint. The preferred ankle position during fixation was 0° dorsiflexion. Removal of the syndesmotic screw was routinely done by most surgeons, mainly because of the limitation of movement and risk of screw breakage. Factors that affect suture button selection included non-rigid fixation which enables adequate fixation, early weight-bearing, and an infrequent need to remove the hardware. Inadequate reduction was considered the main factor that affects poor prognosis. Conclusion: This study proposes updated information about the current trends in the management of syndesmotic injuries in Korea. Consensuses in both the diagnostic and therapeutic approach to patients with syndesmotic injury were identified in this survey study. This study may raise the awareness of the various possible approaches toward the injury and should be used to further establish a standard protocol for the management of syndesmotic injuries.