• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.343-343
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• 2001

최근 전자산업과 전파통신산업의 발달에 따라 불요전자파에 의한 전자파장해가 심각한 수 준에 이르게 되었다. 그 결과 국 . 내외 전자파환경은 나날이 악화되고 있으며, 이로 인한 사 회적 문제가 점차 증가되고 있는 실정이다. 이에 대한 대책으로 CISPR(Comite Internationale S Special des Perturbations Radioelectrique), FCC (Federal Communications Commissions) A ANSI(Amercian National Standards Institute) 둥이 주축이 되어 국제 규정이 제정되어 각종 전자기기들에 대해 방사(EMI) 및 내성(EMS)의 규제가 강화되고 있다. 그러나 국제규정이 요구하는(30 MHz - 18 GHz) 주파수 범위에서의 EMIjEMS 측정을 하기 위해 광대역(Broad-band) 전파무향실(Anechoic Chamber)이 필요하지만1 기존의 Ferrite T Tile 또는 그리드형 전파홉수체는 20 dB 이상 전파를 홉수할 수 잇는 주파수 대역이 30 M MHz - 400 MHz 또는 780 MHz에 불과하기 때문에 상기의 조건을 만족하는 전파무향실 을 구성하기에는 곤란한 실정이다. 본 논문에서는 국제 규격을 만족하는 전파무향실을 위한 광대역 전파홉수체를 개발하기 위해, 다충형으로 구성하고, 전파흡수체의 형상을 변화시켜 등가재료정수법을 사용하여 설계하고 그 특성을 평가함을 그 목적으로 하였다. 따라서 본 논문에서는 본 연구실에서 기폰에 제안한바 있는, 금속판 위에 타일형 페라이 트 충, 그 위에 원추절단형 페라이트 층과 원통형 페라이트 층을 적층시칸 형상의 전파홉수 체는 30 MHz - 6 GHz 정도까지 커버할 수 있으나, 1 GHz 부근의 주파수 대에서 16 dB 정도의 홉수능 밖에 가지지 못하였다. 이를 개선하기 위해, 금속판 위에 타일형 페라이트 층 을 형성하고 그 위에 원통형 페라이트 충, 원추절단형 페라이트 충I 원통형 페라이트 충, 타 원형 페라이트 충을 형성한 새로운 형태의 전파홉수체를 제안하였다. 본 논문에 제안한 새로운 형태의 전파흡수체의 시물레이션 결과 30 MHz - 20 GHz의 주파수 범위에서 전반적으로 25 dB이상의 전파흡수능을 가짐을 확인하였으며/ 특히 기폰에 제안한 전파홉수체와 비교하면,1GHz 부끈에서의 전파홉수능을 10 dB 이상 개선하였다. 나아가서/ 실재로 제작한 전파흡수체의 측정된 주파수특성이 시율레이션에 의한 이론치와 3 30 MHz - 6 GHz의 범위에서 잘 일치함을 확인하였다. 또한y 전파 홉수체의 전체 높이는 2 27 mm 밖에 되지 않으므로 본 연구에서 제안한 전파 홉수체를 사용할 경우 전파무향실의 유 효공간 확보에 매우 유리한 이점을 가진다

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.279-285
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• 1993

Alterations of the p53 gene arc among the most frequent genetic changes in human cancer and often result in increased levels of p53 protein within the malignant cells. Detection of accumulated p53 protein can be a useful prognostic tool in human cancer. In order to make polyclonal antibodies for immunohistochemical screening. human p53 gene was expressed in E. coli in the form of GST (glutathione S-transfi.:rase) fusion proteins. Two p53 gene fragments. which were N('()I small fragment encoding amino acid residues of 1-151-: and Ncol large fragment of 159-393. were subeloned into the unique BamHI site present within the pGEX-2T vector using BamHI linker and recombinant plasmids pGTNS and pGTNL were constructed. respectively. The p53 cDNA fragment (from pC53-$SN_3$,) encoding amino acid 38-145 (proline at residue 72) was amplified by polymerase chain reaction(PCR). The amplified DNA was digested with BamHI and Prull and inserted into the BamHI-Smal sites of pG EX-2T and recombinant plasmid pGTBP was constructed. After IPTG induction of these plasmids for 4 hours. fusion proteins were purified from E. coli extracts with glutathione Sepharose beads. The bound proteins were resolved by 10% SDS-polyacrylamide gel electrophoresis and the molecular weights were 54 kDa. 53 kDa and 40 kDa. respectively. Approximately one milligram of fusion proteins were purified from 1 -liter cultures.

• Journal of the Korean Society of Child Welfare
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• no.56
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• pp.253-281
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• 2016

The purpose of this study was to verify the clinical utility of th Korea Child Behavior Checklist 16-18(K-CBCL 6-18) in diagnosing ADHD among children with psychological disorders in child welfare institutions. The participants were 509 elementary school children(309 boys and 200 girls) who lived in child welfare institutions. They were assessed using the Korean ADHD Rating Scale(K-ARS) and K-CBCL 6-18. Only five scales of the K-CBCL 6-18 related with attention were used for analysis: syndrom total, externalizing total, aggressive behavior, attention problems and DSM-oriented ADHD scales. The results were as follows. First, K-ARS and K-CBCL 6-18 had significantly positive correlations with all five scales. Second, as a result of a t-test on the ADHD and the non-ADHD groups, which were divided using K-ARS, the mean scores of ADHD group were significantly higher than the non-ADHD group for all five scales of the K-CBCL 6-18. The hit rate of all five scales of the K-CBCL 6-18 was 60 to 70 percent. The syndrom total and externalizing total scales had high sensitivity, whereas the aggressive behavior, attention problems, and the DSM-oriented ADHD scales had high specificity. In addition, all scales had high positive predictive values. Third, as the result of a t-test on the ADHD group and the emotional disorder group, there were significant difference in the mean scores of the attention problems and the DSM-oriented ADHD scales. The attention problems and the DSM-oriented ADHD scales had a similar percentage of hit rate, high specificity and low sensitivity. Especially, the DSM-oriented ADHD scale revealed higher specificity than the attention problems scale. The results of this study suggested that the five scales related to attention of the K-CBCL 6-18 are useful in diagnosing ADHD in child welfare institutions.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.369-372
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• 1997

Socket pressure distributions with gait analyses of a transfemoral and a transtibial prostheses were measured in order to assess an optimal socket fitting and unction. Ankle joint was aligned by the neutral and the dorsi/plantar flexed positions. Compared to dorsi and plantar flexed positions of ankle joint, cadence and walking speed increased with the neutral ankle joint alignment. Other gait parameters were close to the normative data with the neutral ankle joint alignment. For the transfemoral amputee, dorsiflexed alignment of the ankle joint created high pressure on the lateral aspect of the socket, on the other hand, plantarflexed alignment resulted in increased pressure on the medial aspect of the socket. For the transtibial amputee, dorsiflexed alignment of the ankle resulted in high pressure on the antero-lateral aspect of the socket during mid-stance, but plantarflexion of the ankle joint showed slight increases in pressure at the same location in the socket. The present study clearly demonstrated that malalignment of a prosthesis results in localized increasing pressure within the socket. Proper alignment of the prosthesis is required in order to acquire an appropriate socket-limb interface as well as the proper gait.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.162-165
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• 2005

The objective of this research work is to investigate into the three-dimensional temperature distribution using quasi steady-state heat transfer analysis fur the case of the laser cutting of CSP 1N sheet using high power CW Nd:YAG laser. The laser heat source is assumed as a volumetric heat source with a gaussian heat distribution in a plane. Through the comparison of the results of analyses with those of the experiments, the optimal finite element model is obtained. Finally, characteristics of the three-dimensional heat transfer and temperature distribution have been estimated by the optimal finite element model.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.62-73
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• 2010

In this paper we proposed a candidate algorithm on G.711.1 and G.722 superwideband extension codec which is under standardization by ITU-T. The proposed codec not only provides an interoperable bitstream with ITU-T G.711.1 and G.722, but also encodes a superwideband signal with a bandwidth of 50-14,000 Hz using superwideband extension layer. The candidate codec consists of a core layer to provide an interoperability with conventional wideband codecs and superwideband extension layer using linear prediction-based sinusoidal coding. The proposed extension codec operates on 5ms frame and provides four superwideband bitrates of 64, 80, 96, and 112 kbit/s depending on the core codec. Since the resulting bitstream has an embedded structure, it can be converted into core bitstream by simple truncation without transcoding. The proposed codec has a short algorithmic delay and low complexity and passed the qualification test of G.711.1 and G.722 superwideband extension codec performed by ITU-T.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.239-255
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• 1997

Expression of the cDNA of the VP1 gene on the genome RNA B segment of infectious pancreatic necrosis virus (IPNV) DRT strain in E. coli and a recombinant baculovirus were carried out. The VP1 gene in the pMal-pol clone (Lee et al. 1995) was cleaved with XbaI and transferred into baculovirus transfer vector, pBacPAK9 and it was named pBacVP1 clone. The VP1 gene in the pBacVP1 clone was double-digested with SacI and PstI and then inserted just behind T5 phage promoter and the $6{\times}His$ region of the pQE-3D expression vector, and it was called pQEVPl. Again, the $6{\times}$His-tagged VP1 DNA fragment in the pQEVP1 was cleaved with EcoRI and transferred into the VP1 site of the pBacVP1, resulting pBacHis-VP1 recombinant. The pBacHis-VP1 DNA was cotransfected with LacZ-Hyphantria cunea nuclear polyhedrosis virus (LacZ-HcNPV) DNA digested with Bsu361 onto S. frugiperda cells to make a recombinant virus. One VP1-gene inserted recombinant virus was selected by plaque assay. The recombinant virus was named VP1-HcNPV-1. The $6{\times}$His-tagged VP1 protein produced by the pQEVP1 was purified with Ni-NTA resin chromatography and analyzed by SDS-PAGE and Western blot analysis. The molecular weight of the VP1 protein was 94 kDa. The recombinant virus, VP1-HcNPV-1 did not form polyhedral inclusion bodies and expressed VP1 protein with 95 kDa in the infected S. frugiperda cells, which was detected by Western blot. The titer of the VP1-HcNPV-1 in the first infected cells was $2.0{\times}10^5\;pfu/ml$ at 7 days postinfection.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.129-141
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• 2001

When oral microorganisms were sampled from occlusal surfaces of caries and non-caries teeth, $3.43\times10^5$ CFU and $3.47\times10^3$ CFU of bacteria were counted on MSB agar plates, respectively. All the 20 colonies isolated from a caries surface were Streptococcus mutans but, only two of 20 colonies were identified as Streptococcus mutans by API test. S. mutans SM1 from caries tooth and S. mutans SM2 from non-caries tooth showed the same results except for $\alpha-galactosidase$ activity on sugar fermentation tests and biochemical tests. For the bacterial replication, both SM1 and SM2 were actively multiplicated at pH 5.5. And the viability of SM1 was high at 20% of sucrose, while that of SM2 was high at 5% of sucrose in the media. SM1 actively replicated at 16mM of $CaCl_2$, 160mM of KCl, and 6.4mM of $MgCl_2$, and the replication of SM2 was increased at 16mM of $CaCl_2$, 40mM of KCl, 6.4mM of $MgCl_2$. At 1mM of sodium bicarbonate and sodium phosphate, both bacteria were actively multiplicated. SM1 and SM2 were actively replicated at 1mM and 10mM of Tris, respectively. For potassium phosphate buffer, SM1 grew well proportionally to the concentration up to 100mM, while the growth of SM2 were inhibited by the increase of concentration. The 4.6 kb of gtf gene was amplified with a pair of primer, gtfB-F961 and gtfC-R5574 by polymerase chain reaction from the chromosomal DNA of SM1 and SM2. When 4.6kb bands were eluted from gel and were treated with restriction enzyme, EcoR I produced the same RFLP like 0.8kb and 3.8kb of DNA fragments for S. mutans GS-5, SM1 and SM2. By Hind III, the PCR products weren't digested for S. mutans GS-5 and SM1, but 3 fragments such as 2.4kb, 1.8kb and 400bp were examined for SM2. These results indicated the difference between gtf genes of SM1 and SM2. BamH I treatment showed 4 fragments for SM1 and SM2, while the 3 fragments for S. mutans GS-5. The PCR products were not digested by Kpn I, Sma I, Xho I and Pst I.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.620-631
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• 2022

Purpose This study aimed to investigate the diagnostic performance of features suggestive of nodal metastasis on preoperative MRI in patients with invasive breast cancer. Materials and Methods We retrospectively reviewed the preoperative breast MRI of 192 consecutive patients with surgically proven invasive breast cancer. We analyzed MRI findings of axillary lymph nodes with regard to the size, long/short ratio, cortical thickness, shape and margin of the cortex, loss of hilum, asymmetry, signal intensity (SI) on T2-weighted images (T2WI), degree of enhancement in the early phase, and enhancement kinetics. Receiver operating characteristic (ROC) analysis, chi-square test, t test, and McNemar's test were used for statistical analysis. Results Increased shorter diameter, uneven cortical shape, increased cortical thickness, loss of hilum, asymmetry, irregular cortical margin, and low SI on T2WI were significantly suggestive of metastasis. ROC analysis revealed the cutoff value for the shorter diameter and cortical thickness as 8.05 mm and 2.75 mm, respectively. Increased cortical thickness (> 2.75 mm) and uneven cortical shape showed significantly higher sensitivity than other findings in McNemar's test. Irregular cortical margins showed the highest specificity (100%). Conclusion Cortical thickness > 2.75 mm and uneven cortical shape are more sensitive parameters than other findings, and an irregular cortical margin is the most specific parameter for predicting axillary metastasis in patients with invasive breast cancer.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.327-337
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• 1999

Background: Reactive oxygen species are involved in multi-stage process of carcinogenesis. The moot of cancer cell lines and cancer cells in tumor tissue produce reactive oxygen species and on the other hand, the activities of catalase, Mn- and CuZn-superoxide dismutase in tumor cells are usually low. These persistent oxidative stress in tumor tissue facilitates tumor invasion and metastasis. 12-kDa thioredoxin, which regulates the intracellular redox potential with glutathione and glutaredoxin is involved in cell activation, proliferation, differentiation and redox-mediated apoptosis. It is also purified as 14-kDa and 10-kDa eooinophilic cytotoxic enhancing factor(ECEF) from human histiocytic cell(U937) and 10-kDa ECEF has more than 20 times eosinophilic stimulation activity than 14-kDa ECEF. It has been reported that adult T-cell leukemia, squamous cell carcinoma of uterine cervix, and hepatocellular carcinoma show increased amounts of human thioredoxin and thioredoxin mRNA is increased in lung cancer. In this study, we investigated the expression of conventional antioxidant enzymes such as catalase, CuZn-SOD, and glutathione peroxidase and thioredoxin in lung cancer tissue compared to adjacent normal lung tissue and the induction of thioredoxin in macrophage cells after treatment of oxidative stress and endotoxin Methods: We measured the amount of conventional antioxidant enzymes such as catalase, CuZn-SOD, and glutathione peroxidase and thioredoxin in lung cancer tissue compared to adjacent normal lung tissue by immunoblot analysis and the induction of thioredoxin in mouse monocyte-macrophage cells(RAW 264.7) by treatment of 5 ${\mu}M$ menadione and 1 ${\mu}g/ml$ endotoxin Results: On immunoblot analysis, the expression of 12-kDa thioredoxin was increased in lung cancer tissue compared to paired normal lung tissue. but the expression of catalase and CuZn-SOD were decreased in lung cancer tissue compared to paired normal tissue and the expression of glutathione peroxidase in lung cancer was variable. The expression of truncated thioredoxin was also increased in lung cancer. When mouse monocyte-macrophage cells were treated with 5 ${\mu}M$ menadione and 1 ${\mu}g/ml$ endotoxin, the expression of thioredoxin was peaked at 12 hrs and sustained to 48 hrs. Conclusion: In contrast with other conventional antioxidants, the expression of 12-kDa and truncated thioredoxin in lung cancer were increased and it is closely associated with persistent oxidative stress in tumor microenvironment. Considering especially the biological functions of truncated thioredoxin, the increased amount of truncated thioredoxin has significant role in tumor growth through cell proliferation.