청양 지역에 분포하는 트라이아스기 후기의 조계리층에서 산출된 규화목 화석

김종헌,백승덕,이원국 공주대학교 과학교육연구소 2003 과학교육연구 Vol.34 No.-

충남 청양 지역에 분포하는 트라이아스기 후기의 조계리층에서 규화목 화석이 발견되었다. 규화목 화석의 산출은 남한에 분포하는 하부중생계 지층에서 최초의 기록이다. 분류학적 연구결과, 구과류에 속하는 Xenoxylon sp.와 Dadoxylon sp.의 2속 2종이 식별되었다. 본 논문에서 구과류 화석의 특징과 비교 및 그 의미에 대해서 고찰하였다. Petrified wood fossils are discovered from the Upper Triassic Jogyeri Formation distributed in the Cheongyang area. The occurrence of petrified fossils is the first record in the Lower Mesozoic strata distributed in South Korea. As a result of anatomical study of wood fossils, two specie belonging to two genera of Xenoxylon sp. and Dadoxylon sp. which belong to conifers, are recognized. This paper deals with the characteristics, comparison and significance of conifer wood fossils.

한국인 부정교합자의 하악 치열궁의 크기와 형태

이성준,백승학,김상철,국윤아 대한치과교정학회 2005 대한치과교정학회지 Vol.35 No.1

본 연구의 목적은 한국인 부정교합자에서 하악 치열궁간의 형태적 차이를 알아보고자 하였다. Ⅰ급 114명. Ⅱ급 119명, Ⅲ급 135명의 부정교합자를 대상으로 하악 모형의 교합면을 복사한 후 13개의 접촉점 중에서 가장 협측면으로 위치한 부분을 digitize 하였고 각 치아의 브라켓 위치에 해당하는 점을 하악치아의 두께에 의거하여 4개의 선계측과 2개의 비율을 측정하였다. 치열궁의 형태는 square ovoid, tapered형으로 분류하여 그 빈도를 조사한 결과 Angle 분류와 남녀 성별에 따른 특별한 치열궁 형태가 존재하지 않았으나, 특정 치열궁 형태의 빈도는 Angle 분류에 따라 다르게 나타났다. 치열궁 크기의 계측항목에서는 대구치간 폭경에서만 남녀 성별 차이를 보였으며, 치열궁 크기에 있어서 Ⅰ급과 Ⅲ급, Ⅱ급 부정교합군간에는 유의한 차이가 있었다. 치열궁 형태의 분포는 Ⅰ급과 Ⅲ급 부정교합군에서는 square, ovoid, tapered 형태 순이었고, Ⅱ급 부정교합군은 square, tapered ovoid 형태 순이었다. 치열궁 형태의 빈도분포에 있어서는 남녀간의 차이는 없었다. The purpose of this study was to clarify morphological differences among mandibular dental arch forms in Korean malocclusion patients. The sample in this study consisted of 114 Class Ⅰ, 119 Class Ⅱ, and 135 Class Ⅲ malocclusion cases. The most facial portions of 13 proximal contact areas were digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on the data of the mandibular tooth thickness. Four linear and two proportional measurements were undertaken. The dental arches were classified into square, ovoid, and tapered forms to compare the frequency distributions. Our results suggested that there was no single arch form specific to any particular Angle classification or sex. It appeared to be the frequency of a particular arch form that varies among the Angle classifications. In comparison of arch measure between male and female, there was no statistical difference except in the intermolar width. In comparison of arch size measurements among the different Angle classifications, there were statistically significant differences between Class Ⅰ and Class Ⅲ malocclusion groups and between Class Ⅱ and Class Ⅲ malocclusion groups. In comparison of frequency distribution of arch forms in Class Ⅰ and Ⅲ malocclusion groups, the square form demonstrated the highest distribution followed by the ovoid and tapered forms in that order. In the Class Ⅱ malocclusion group, the square form showed the highest distribution, followed by the tapered and ovoid forms in that order. There was no statistical difference in the frequency distribution of arch forms between male and female groups.

Agrobacterium을 이용한 고추의 형질전환체계개발

최근원,박영두,박승국,전영주,유일웅,김인태,백운돈 경희대학교 생명자원과학연구원 1997 硏究論文集 Vol.18 No.-

본 실험은 고추의 형질전환체 선발을 위한 최소의 항생제농도를 결정하고 그 결과를 이용하여 형질전환체를 유기하고 효율을 최대화하기 위하여 수행한 바 그 결과는 다음과 같다. 1. 항생제 감응성 검정결과 kanamycin 40㎎/ℓ와 hygromycin 20 ㎎/ℓ에서 신초형성이 완전히 억제되었다. 2. Agrobacterium 제거에 사용되는 carbenicillin과 cefotaxime 처리시 재분화에 아무런 영향을 미치지 않았으며 cefotaxime 200㎎/ℓ 처리에서는 무처리구보다 신초형성이 더 활발하였다. 3. 회복친인 135Q와 276F에서는 형질 전환시 높은 재분화율을 보였으나 형질전환율은 각각 10%와 11.1%의 낮은 빈도를 보였다. 4. 재분화된 신초들을 대상으로 histochemical GUS assay를 실시한 결과 부분적으로 푸른발색이 확인되었다. 5. GUS활성을 보인 신초들에 대한 NPTⅡprimer를 이용한 PCR검정에서 NPTⅡ 유전자의 존재가 확인되었다. A transformation system using Agrobacterium tumefaciens was developed with different genotypes of hot peppers (Capsicum annuum). Four antibiotics commonly used in Agrobacterium-mediated transformation were tested for their effects on shoot regeneration. Shoot induction was completely inhibited by kanamycin at 40㎎/ℓ and hygromycin at 20㎎/ℓ or higher, but not by carbenicillin and cefotaxime. Cotyledon explants of hot peppers were cocultivated with Agrobacterium turnefaciens LBA4404 which carries a binary. vector pBI121 harboring the neomycin phosphotransferase, type Ⅱ (NPT Ⅱ) gene and β-glucuronidase (GUS) gene. For selection of transformed cells, 40㎎/ℓ kanamycin were used because the sensitivity test showed that 40㎎/ℓ kanamycin completely inhibited shoot induction from nontransformed cells. Histochemical GUS assay showed the presence of the GUS gene and PCR analysis confirmed the NP TⅡ gene was integrated. Transformation frequency was about 10.0% and 11.1% of total regenerants from 135Q and 276F, respectively.

절삭력 추정을 위한 CNC 이송계의 파라미터 식별

백승국(Seung Guk Baek),이성철(Sung-chul Lee),송창규(Chang Kyu Song),노승국(Seung Kook Roh) 한국생산제조학회 2020 한국생산제조시스템학회 학술발표대회 논문집 Vol.2020 No.12

폐경기 여성에서 나이관련황반변성과 여성 호르몬 요인과의 관계: 제5기 국민건강영양조사 자료

백승국(Seung Kook Baek),이영훈(Young Hoon Lee) 대한안과학회 2017 대한안과학회지 Vol.58 No.9

Purpose: To investigate whether endogenous and exogenous female hormone exposures were associated with risks for age-related macular degeneration (AMD) in postmenopausal women. Methods: This study included 4,479 postmenopausal females aged 45 years and older who completed the Korea National Health and Nutrition Examination Survey (KNHANES) V. The participants were divided into 4 groups: subjects with AMD, subjects without AMD, subjects with early AMD, and subjects with late AMD. Variables associated with endogenous and exogenous female hormone exposures were analyzed. Results: Among the 4,479 participants, 516 were found to have AMD and 3,963 were normal. There was no significant difference between the AMD and normal groups execpt for age in the risk analysis. Of the total 516 AMD participants, 488 had early AMD and 28 had late AMD. Women with AMD who had used oral contraceptives longer in the past had significantly higher odds of late AMD than early AMD (odds ratio [OR] = 1.013, 95% confidence interval [CI]: 1.002-1.024). Increasing number of children was also associated with decreased odds of late AMD (OR = 0.672, 95% CI: 0.506-0.893). Conclusions: These findings suggest that exposure to endogenous and exogenous female hormones may influence the risk of AMD progression. J Korean Ophthalmol Soc 2017;58(9):1066-1073

Overjet at the Anterior and Posterior Segments: Three-Dimensional Analysis of Arch Coordination

Kook, Yoon-Ah,Bayome, Mohamed,Park, Soo-Byung,Cha, Bong-Kuen,Lee, Young-Wuk,Baek, Seung-Hak The Angle Orthodontist 2009 The Angle orthodontist Vol.79 No.3

<B>Abstract</B><P>Objectives: To compare the amounts of anatomical overjet measured from facial axis (FA) points with the amounts of bracket overjet measured from bracket slot center (BSC) points.</P><P>Materials and Methods: The samples consisted of 27 subjects with normal occlusion whose models were fabricated with a three-dimensional (3D) scanner and the 3Txer program (Orapix Co Ltd, Seoul, Korea). 3D virtual brackets (0.022″ Slot, MBT setup, 3M Unitek, Monrovia, Calif) constructed with a 3D-CAD program were placed on an FA point with the 3Txer program. The arch dimension and the amounts of overjet from FA and BSC points were measured. Paired t-tests and analysis of variance (ANOVA) tests were used for statistical analysis.</P><P>Results: No significant difference in arch width and depth was observed between FA and BSC points. Although the amounts of overjet measured from FA points showed homogenous distribution, a tendency to decrease from the anterior segment (2.3 mm) to the posterior one (2.0 mm) was noted. However, the amounts of overjet measured from BSC points were variable, especially in the premolar and molar areas. Significant discrepancies in the amounts of overjet in most of the areas between FA and BSC points (more than P &lt; .05), except the lower second premolar and second molar areas, were reported, even though insets and offsets are part of the prescription for the base of straight-wire appliance (SWA) brackets.</P><P>Conclusions: The hypotheses that the amount of overjet measured from BSC points was 3 mm through the whole segments and that distribution of the amounts of overjet from BSC points was the same as that from FA points were rejected.</P>

The Optimal Treatment Strategy in Hormone Receptor-positive, Human Epidermal Growth Factor Receptor 2-negative Breast Cancer Patients with 1-2 Suspicious Axillary Lymph Node on Breast MRI: Upfront Surgery vs.Neoadjuvant Chemotherapy?

Seung Eun Lee,Soong June Bae,Sung Gwe Ahn,Jung Hwan Ji,Yoonwon Kook,Ji Soo Jang,Seung Ho Baek,Joon Jeong 대한외과학회 2022 대한외과학회 학술대회 초록집 Vol.2022 No.5

Better Failure-Free Survival and Graft- versus-Host Disease-Free/Failure Free Survival with Fludarabine-Based Conditioning in Stem Cell Transplantation for Aplastic Anemia in Children

Seung Hwan Im,김보람,Soo Min Park,윤보애,Tai Ju Hwang,Hee Jo Baek,Hoon Kook 대한의학회 2020 Journal of Korean medical science Vol.35 No.7

Background: This study aimed to assess the outcome of stem cell transplantation (SCT), including overall survival (OS), failure-free survival (FFS) and graft-versus-host disease (GvHD)-free/failure-free survival (GFFS), and to analyze prognostic factors in children with aplastic anemia (AA). Methods: From 1991 to 2018, 43 allogeneic SCT recipients were enrolled in the study to investigate the demographic characteristics, survival outcomes and prognostic factors. Results: With the median follow-up of 7.1 years, the estimated 10-year OS, FFS, GFFS were 86.0%, 60.5%, and 51.2%, respectively. Matched related donors (MRD, n = 28) showed better 10-year OS than unrelated donors (n = 15) (96.4% vs. 66.7%; P = 0.006). Engraftment failure was seen in 13 patients (30.2%). Donor-type aplasia was seen in 13.8% (4/29) after fludarabine (Flu)-based conditioning (Flu-group), while in 42.6% (6/14) after cyclophosphamide (Cy)-based regimen (Cy-group) (P = 0.035). Six patients died. The 10- year OS in Cy-group was 92.9% (n = 14, all MRD), while that of Flu-group was 82.1% (n = 29; P = 0.367). But Flu-group tended to have better FFS and GFFS than Cy-group, although Flu-group had less MRDs (41.4% vs. 100%; P = 0.019), and higher proportion of previous immunosuppressive treatment (IST; 62% vs. 21.4%, P = 0.012). In MRD transplants, OS was similar between Flu-group (100%, n = 14) and Cy-group (92.9%, n = 14), while FFS (100.0% vs. 42.9%; P = 0.001) and GFFS (85.7% vs. 35.7%; P = 0.006) were significantly better in Flu- group. Stem cell sources, irradiation in the conditioning, and method of GvHD prophylaxis did not significantly influence the outcome. Conclusion: This study reviewed SCT outcomes for pediatric AA with changes of transplant strategies over the last 25 years. The FFS and GFFS were higher in Flu-group than in Cy- group, especially in matched related transplantation. Graft failure including donor-type aplasia remains troublesome even with Flu-based conditioning. Further refinement of transplant strategies to ensure better quality-of-life should be pursued.

Comparison of FcRγ-Deficient and CD57+ Natural Killer Cells Between Cord Blood and Adult Blood in the Cytomegalovirus-Endemic Korean Population

Baek, Hee Jo,Kim, Da-Woon,Phan, Minh-Trang Thi,Kim, Ju-Sun,Yang, Ji-Hoon,Choi, Jeong Il,Lee, Je-Jung,Shin, Myung-Geun,Ryang, Dong-Wook,Kim, Sang-Ki,Lee, Seung-Hwan,Kook, Hoon,Cho, Duck The Korean Society for Laboratory Medicine 2015 Annals of Laboratory Medicine Vol.35 No.4

<P><B>Background</B></P><P>FcRγ-deficient natural killer (NK) cells (g<SUP>-</SUP>NK cells) have been associated with cytomegalovirus (CMV) infection. However, the frequency of g<SUP>-</SUP>NK cells in a CMV-endemic area (i.e., Korea) has not yet been studied. We examined the frequency of g<SUP>-</SUP>NK cells and expression of CD57 on NK cells in cord blood (CB) and adult blood (AB).</P><P><B>Methods</B></P><P>Of the 24 AB samples collected, 95.8% (23/24) were CMV IgG<SUP>+</SUP>/IgM<SUP>-</SUP>, while 100% of the 13 healthy CB samples were CMV IgG<SUP>+</SUP>/IgM<SUP>-</SUP>. We performed whole-blood flow cytometry assays to analyze intracellular FcRγ and CD3ζ expression of CD3<SUP>-</SUP>/CD56<SUP>dim</SUP> NK cells from 13 CB and 24 AB samples, and surface CD57 expression on CD3<SUP>-</SUP>/CD56<SUP>dim</SUP>/CD16<SUP>+</SUP> NK cells from 13 CB and 19 AB samples.</P><P><B>Results</B></P><P>All CMV seropositive AB samples contained g<SUP>-</SUP>NK cells (23/23), and the median proportion of g<SUP>-</SUP>NK cells in the CD3<SUP>-</SUP>/CD56<SUP>dim</SUP> NK cell pool was 35.0% (range: 11-77%). CD57<SUP>+</SUP> NK cells in the CD3<SUP>-</SUP>/CD56<SUP>dim</SUP>/CD16<SUP>+</SUP> NK cell population were detected in all 19 AB samples tested, but not in any CB samples.</P><P><B>Conclusions</B></P><P>Our data suggest that g<SUP>-</SUP>NK cells and CD57<SUP>+</SUP> NK cells are present at a very high frequency in CMV-seropositive AB, but rare in CMV-naïve CB.</P>

식이내(食餌內) Cadmium 수준차이에 따른 생쥐 체내에서의 Cadmium 축적(蓄積)에 관한 연구

백승화,김성조,국중화 한국환경농학회 1991 한국환경농학회지 Vol.10 No.1

Cd添加量과 Cd源을 달리하여 調製한 飼料로 생쥐를 12週間 飼育한 後 體重과 생쥐내 臟器의 무게에 따른 成長速度를 調査하고 생쥐의 臟器들 卽, 腎臟, 肝, 心臟, 허파, 脾臟 및 全血中에 蓄積되는 Cd蓄積作用을 分析한 結果는 다음과 같다. 1. 飼育時期 9週째에 생쥐의 體重增加는 Cd添加水準에 따라 달라져서 飼料中의 Cd을 많이 添加하여 飼育하는 생쥐일수록 體重이 적어졌다. 2. 臟器의 무게는 Cd無添加 飼料로 飼育한 생쥐가 腎臟, 肝, 心臟, 脾臟 等의 臟器의 種類에 關係없이 무거웠다. 그러나 Cd을 添加하여 生育한 생쥐에서는 Cd添加水準差異에 따른 臟器의 무게 差異를 認定하기 어려웠다. 3. 臟器內에 Cd蓄積作用은 腎臟과 肝에서 가장 높았고 心臟이 그 다음이었으며 蓄積濃度는 飼料中의 Cd含量이 많을수록 높아지는 比例的 關係를 나타내었다. 4. 飼料中 Cd濃度가 낮을수록 모든 臟器 및 血液에 蓄積되는 比率이 높아짐을 알 수 있었다. An animal experiment was performed to investigate the effects of dietary cadmium on growth rates and cadmium accumulations in internal organic tissues and blood by feeding mice with dietary cdcl₂ additives and/or brown rice with high cadmium content as during a 12-week feeding period. The results were as follows : Mice weights decreased with increasing levels of dietary cadmium at the end of a 9-week feeding period. The weights of mice organs in the cadmium-free feeding group were higher than in the cadmium-added groups, and the weights of mice organs did not show any significant differences among feeding groups with different levels of dietary cadmium. The concentrations of cadmium in kidney and liver were much higher than in other internal organs and blood, and the next higher concentration was in the heart. The cadmium accumulation in all internal organs and blood increased with increasing dietary cadmium levels, respectively. The ratios of cadmium accumulation in organ tissues and total blood of cadmium-added groups increased with decreasing dietary cadmium levels.