• 한국정보통신학회논문지
• /
• 제12권4호
• /
• pp.772-780
• /
• 2008

K-means는 알고리즘의 단순함과 효율적인 구현이 가능함으로 인해 군집화를 위해 현재까지 널리 사용되는 방법 중 하나이다. 하지만 K-means는 집단의 개수가 사전에 결정되어야 하는 근본적인 문제점이 있다. 이 논문에서는 BIC(Bayesian information criterion) 점수를 이용하여 효율적으로 집단의 개수를 추정할 수 있는 X-means 알고리즘을 확장한 두 가지 알고리즘을 제안한다. 제안한 방법은 기본적으로 X-means 방법을 따르면서 집단이 임의의 분산 행렬을 가질 수 있도록 함으로써 X-means 알고리즘이 원형 집단만을 허용함에 따른 over-fitting을 개선한다. 제안한 방법은 하나의 집단에서 시작하여 계속해서 집단을 나누어가는 하향식 방법으로, BIC score를 최대로 증가시키는 집단을 분할해 나간다. 제안한 알고리즘은 Modified X-means(MX-means)와 Generalized X-means(GX-means)의 두 가지로, 전자는 K-means 알고리즘을, 후자는 EM 알고리즘을 사용하여 현재 주어진 집단들에서 최적의 분할을 찾아낸다. MX-means는 GX-means보다 그 속도에서 앞서지만 집단들이 중첩 된 경우에는 올바른 집단을 찾아낼 수 없는 단점이 있다. GX-means는 실행 속도가 느린 단점이 있지만 집단들이 중첩된 경우에도 안정적으로 집단들을 찾아낼 수 있다. 이러한 점들은 일련의 실험을 통해서 확인할 수 있으며, 제안한 방법들이 기존의 방법들에 비해 나은 성능을 보임을 확인할 수 있다.

• 한국방사선학회논문지
• /
• 제12권7호
• /
• pp.887-893
• /
• 2018

본 연구는 병원 및 대학교 등에 설치된 X선 발생장치를 대상으로 진단용 방사선 발생장치의 품질관리 항목을 적용하여 성능 비교를 하여 주기적인 성능관리의 중요성을 인식시켜 성능유지 및 관리에 도움을 주고자 한다. 우선 재현성 및 직선성 실험결과 모든 실험조건에서 합격기준에 부합되었으며 주기적인 정도관리가 부족한 GX-650장치의 경우 재현성 평가의 백분율 오차가 높았으며 직선성 평가에서는 관전압을 100 kVp로 설정 시 0.105로 백분율 오차에서 벗어나게 측정되었다. 또한 관전압 및 관전류의 정확도 평가결과 상대적으로 X선 발생횟수가 낮은 장치에서 백분율 오차가 낮은 것을 알 수 있었다. 반가층 실험은 모든 장치에서 관전압 별 반가층 기준에 모두 포함되었다. 따라서 병원용, 실습용 구분보다는 모든 장치의 정도관리의 중요성을 인식하고 적극적으로 장치의 성능관리를 시행하여 장치를 유지 관리해야 할 것이며 특수의료장비처럼 짧은 주기의 정도관리 제도를 마련해야 할 것으로 사료된다.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.423.2-424
• /
• 2002

The present study evaluates the pharmacokinetics and tissue distribution of GX-12, a multiple plasmid DNA vaccine for the treatment of HIV-1 infection. PCR analysis after i.v. injection in mice showed that plasmid DNA was rapidly degraded in blood with a half-life of 1.34 min and was no longer detectable at 90 min post-injection. Plasmid DNA concentration also rapidly declined at the injection site after i.m. injection. with less than 1 % of the initial concentration remaining at 90 min post-injection. (omitted)

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권12호
• /
• pp.1666-1673
• /
• 2011

The presence of sialoglycoproteins (SGPs) in the membranes from goat (Capra aegagrus hircus), buffalo (Bubalus bubalis bubalis) and pig (Sus scrofa domestica) erythrocytes was investigated by partial purification with a chloroform-methanol extraction method followed by Sodium dodecyl sulphate - Polyacrylamide gel electrophoresis in comparison to human (Homo sapiens) erythrocytes. The results show that mammalian erythrocytes possess clear differences in the SGPs numbers and molecular weights although all animals studied in this experiment are from the same class i.e. mammalia. The SGPs number in human, goat, buffalo and pig are four (PAS-1 to PAS-4), ten (PAS-GI to PAS-GX), seven (PAS-BI to PAS-BVII) and four (PAS-PI to PAS-IV) respectively as indicated by staining the polyacrylamide gel with sialoglycoprotein-specific Periodic acid-Schiff's (PAS) stain. The new SGPs could be observed only after the partial purification of membrane fractions named as PAS-HI with molecular weight (Mr) 190 kDa and PAS-HII 150 kDa in human, PAS-BIA in buffalo and PAS-PIA and PAS-PIVA in pig. The gels were also stained with Coomassie brilliant blue (CBB) and Silver stain to check the contamination of other membrane proteins in the purified fractions. The quantitative distribution of SGPs was also determined by densitometry. Present study indicates that there are some basic differences in mammalian erythrocyte membrane SGPs, especially with respect to their number and molecular weights indicating major structural variations.

• The Korean Journal of Physiology and Pharmacology
• /
• 제12권3호
• /
• pp.125-129
• /
• 2008

The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) of matrix metallopeptidase 2 (MMP2) are associated with obesity. MMP2 is an enzyme with proteolytic activity against matrix and nonmatrix proteins, particularly basement membrane constituents. To identify the relationship between polymorphisms of MMP2 and overweight/obese, we genotyped 5 SNPs (rs17242319, rs1053605, rs243849, rs2287074, and rs10775332) of the coding region of MMP2 using the Golden Gate assay on an Illumina BeadStation 500 GX. One hundred and forty two overweight/obese ($BMI\;{\ge}\;23$) and 145 normal (BMI 18 to < 23) subjects were analyzed. SNPStats, Haploview, HapAnalyzer, SNPAnalyzer, and Helixtree programs were used for the analysis of genetic data. A linkage disequilibrium (LD) block was discovered among the 5 SNPs selected, including rs17242319, rs1053605, rs243849, and rs2287074. Of the 5 polymorphisms, 2 synonymous SNPs [rs17242319 (Gly226Gly) and rs10775332 (Phe602Phe)] were found significant associations with overweight/obese. Recently, rs1132896 replaced rs17242319 as a new number (SNP database, BUILD 129). In haplotype analysis using Haploview, a haplotype (haplotype: CCCA) containing a meaningful polymorphism (rs17242319) was found to be significantly different. The results suggest that MMP2 may be associated with overweight/obese in Korean population.

• The Korean Journal of Physiology and Pharmacology
• /
• 제12권4호
• /
• pp.205-209
• /
• 2008

Recently, Sun et al (2008) reported that the IL6R polymorphism is associated with schizophrenia. Therefore, to detect the association between polymorphisms of interleukin 31 receptor A (IL31RA) and schizophrenia, we genotyped 9 SNPs [rs9292101 (intron 1), rs1009639 (exon 2, Pr043Pro), rs2161582 (intron 2), rs68761890 (intron 5), rs16884629 (intron 6), rs11956465 (intron 12), rs12153724 (intron 12), and rs16884641 (intron 14)] using the Golden Gate assay on Illumina BeadStation 500 GX. Two hundred eighteen patients with schizophrenia and 379 normal subjects were recruited. Patients with schizophrenia were diagnosed according to DSM-IV, and control subjects without history of psychiatric disorders were selected. We used SNPStats, Haploview, HapAnalyzer, SNPAnalyzer, and Helixtree programs for the evaluation of genetic data. Of nine polymorphisms, three SNPs (rs9292101, rs1009639, and rs11956465) were associated with schizophrenia. The rs9292101 and rs11956465 showed significant associations with the risk of schizophrenia in the codominant [rs9292101, odds ratio (OR)=0.74, 95% confidence interval (CI)=0.58${\sim}$0.95, p=0.017] and recessive (rs11956465, OR=0.64, 95% CI=0.42${\sim}$0.96, p=0.034) models, respectively. The rs1009639 also was statistically related to schizophrenia in both codominant (OR=0.76, 95% CI=0.60${\sim}$0.97, p=0.025) and dominant (OR=0.66, 95% CI=0.44${\sim}$0.98, p=0.035) models. Two linkage disequilibrium (LD) blocks were made. In the analysis of haplotypes, a haplotype (GCT) in block 1 and a haplotype (CCACAG) in block 2 showed significant associations between schizophrenia and control groups (haplotype GCT, frequency=0.509, chi square=4.199, p=0.040; haplotype CCACAG, frequency=0.289, chi square=5.691, p=0.017). The results suggest that IL31RA may be associated with risk of schizophrenia in Korean population.

• 대한치과보철학회지
• /
• 제31권4호
• /
• pp.580-610
• /
• 1993

The purpose of this study was to analyse the deflection and stress distribution at the supporting bone and it's superstructure by the alteration of angulation between implant and it's implant abutment. For this study, the free-end saddle case of mandibular first and second molar missing would be planned to restore with fixed prosthesis. So the mandibular second premolar was prepared for abutment, and the cylinder type osseointegrated implant was placed at the site of mandibular second molar for abutment. The finite element stress analysis was applied for this study. 13 two-dimensional FEM models were created, a standard model at $0^{\circ}$ and 12 models created by changing the angulation between implant and implant abutment as increasing the angulation mesially and distally with $5^{\circ}$ unittill $30^{\circ}$. The preprocessing decording, solving and postprocessing procedures were done by using FEM analysis software PATRAN and SUN-SPARC2GX. The deflections and von Mises stresses were calculated under concentrated load (load 1) and distributed load(load 2) at the reference points. The results were as follows : 1. Observing at standard model, the amount of total deflection at the distobuccal cusp-tip of pontic under concentrated load was largest of all, and that at the apex of implant was least of all, and the amount of total deflection at the buccal cusp-tip of second premolar under distributed load was largest of all, and that at the apex of implant was least of all. 2. Increasing the angulation mesially or distally, the amounts of total deflection were increased or decreased according to the reference points. But the order according to the amount of total deflection was not changed except apex of second premolar and central fossa of implant abutment under concentrated load during distal inclination. 3. Observing at standard model, the von Mises stress at the distal joint of pontic under concentrated load was largest of all, and that at the apex of implant was least of all. The von Mises stress at the distal margin of second premolar under distributed load was largest of all, and that at the apex of Implant was least of ail. 4. Increasing the angulation of implant mesially, the von Mises stresses at the mesial crest of implant were increased under concentrated load and distributed load, but those were increased remarkably under distributed load and so that at $30^{\circ}$ mesial inclination was largest of all. 5. Increasing the angulation of implant distally, the von Mises stresses at the distal crest of implant were increased remarkably under concentrated load and distributed load, and so those at $30^{\circ}$ distal inclination were largest of all.

• The Plant Pathology Journal
• /
• 제38권1호
• /
• pp.12-24
• /
• 2022

In this study, we conducted whole-genome sequencing with six species of Pectobacterium composed of seven strains, JR1.1, BP201601.1, JK2.1, HNP201719, MYP201603, PZ1, and HC, for the analysis of pathogenic factors associated with the genome of Pectobacterium. The genome sizes ranged from 4,724,337 bp to 5,208,618 bp, with the GC content ranging from 50.4% to 52.3%. The average nucleotide identity was 98% among the two Pectobacterium species and ranged from 88% to 96% among the remaining six species. A similar distribution was observed in the carbohydrate-active enzymes (CAZymes) class and extracellular plant cell wall degrading enzymes (PCWDEs). HC showed the highest number of enzymes in CAZymes and the lowest number in the extracellular PCWDEs. Six strains showed four subsets, and HC demonstrated three subsets, except hasDEF, in type I secretion system, while the type II secretion system of the seven strains was conserved. Components of human pathogens, such as Salmonella pathogenicity island 1 type type III secretion system (T3SS) and effectors, were identified in PZ1; T3SSa was not identified in HC. Two putative effectors, including hrpK, were identified in seven strains along with dspEF. We also identified 13 structural genes, six regulator genes, and five accessory genes in the type VI secretion system (T6SS) gene cluster of six Pectobacterium species, along with the loss of T6SS in PZ1. HC had two subsets, and JK2.1 had three subsets of T6SS. With the GxSxG motif, the phospholipase A gene did locate among tssID and duf4123 genes in the T6SSa cluster of all strains. Important domains were identified in the vgrG/paar islands, including duf4123, duf2235, vrr-nuc, and duf3396.

• 대한핵의학회지
• /
• 제28권2호
• /
• pp.186-191
• /
• 1994

Tc-99m methoxyisobutyisonitrile(이하 MIBI)는 지용성양이온으로 심근혈류검사에 널리 쓰이고 있으나, 갑상선암, 폐암, 유방암 등 각종 암조직에도 섭취된다고 보고되었으며, 일부에서는 치료에 의한 반응을 판정하는데도 유용하다고 보고하고 있으나, 폐암에서 방사선치료에 의해 암부위의 섭취가 어떻게 변하는지에 대한보고는 찾아보기 힘들다. 이에 저자들은 한국에서 그 빈도가 급격히 증가하고 있는 폐암 병소의 국소화 및 방사선치료의 경과를 판정하는데 있어 Tc-99m MIBI SPECT가 유용한지 검토하기 위해 본 연구를 시도하였다. 조직학적으로 확진된 폐암환자 20예를 대상으로 하였으며, 이 중 11예에서는 방사선 치료 전후에 검사할 수 있었다. 대상환자의 평균연령은 59세(범위 45-66세), 남녀비는 19 : 1이었고, 조직학적 진단명은 편평상피세포암(squamous cell ca, 이하 SCC) 16예, 선암(adenoca, 이하 AC) 4예였다. 대상환자는 별다른 전처치를 하지 않은 상태에서 Tc-99m $MIBI740MB_q$(20mCi)를 정맥주사하고, 1시간 후에 감마카메라(Sopha DSX, Sopha Medical, France)를 이용하여 $256{\times}256$매트릭스, 50만 카운트의 흉부 전면상을 얻었다. 이어 환자의 흉부를 360 도에 걸쳐 12도 간격으로 10초씩 $64{\times}64$ 또는 $128{\times}128$ 매트릭스로 단층촬영을 시행하였으며, 얻어진 영상자료는 감마카메라에 접속된 핵의학전용 컴퓨터(Sopha GX, Columbia, USA)에 수면상에서 폐암병소와 반대측 정상체에 관심구역을 설정하고, 이곳의 방사능을 측정하였다. 폐암병소와 Tc-99m MEBI 섭취율은(폐암병소의 방사능/정상 폐의 방사능)${\times}100$으로 계산하였다. 방사선치료 전후에 Tc-99m MIBI SPECT를 시행하였던 11예(남 : 여=10 : 1, 평균 연령 59세, 범위 50-66세, SCC 8예, AC 3예)에서는 단순흉부방사선 검사 및 CT 촬영결과와 Tc-99m MIBI SPECT결과를 비교하였다. 평균 6453cGy의 조사를 하였으며, 조사전 및 조사후 1개월째 단순흉부 촬영 및 CT를 하여 치료반응을 평가하였다. 통계학적 분석을 위해 조직학적 소견별 Tc-99m MIBI 섭취율의 비교는 student's t-test를 이용하였고, 방사선 치료전후 Tc-99m MIBI 섭취율의 변화는 paired t-test를 이용하여 검정하였다. P값 0.05미만을 유의한 것으로 판정하였다. 대상환자 전례에서 폐암병소에 뚜렷한 Tc-99m MIBI의 섭취가 관찰되었으며, SCC환자의 Tc-99m MIBI 섭취율은 평면상에서 $1.50{\pm}0.16$, 단면상에서 $2.73{\pm}0.46$였으며, AC환자의 섭취율은 각각 $1.45{\pm}0.15,\;2.54{\pm}0.37$으로 양군간에 유의한 차이를 인정 할 수 없었다. 방사선학적으로 호전된 예는 11예 중5예(45.5%, SCC 4예, AC 1예)였으며, 11예 중 9예(81.8%)에서 방사선학적 검사결과와 Tc-99m MIBI섭취율의 변화가 일치하였다. 결론적으로, Tc-99m MIBI SPECT는 폐암병소의 국소화 및 방사선치료 효과의 판정에 어느정도 유용하리라 사료되었다.