• 대한기계학회논문집
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• 제11권1호
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• pp.44-52
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• 1987

본 논문에서는 앞서의 연구들에서 얻은 연구성과를 실제의 디이젤기관에 적용 시켜 화염의 발달상태와 기관속도의 상승 등을 고찰하여, 그 유효성을 평가했다. 또 고온공기류덕트에서는 실험하기가 곤란했던, 분무자체에 족회운동을 일으킨 경우의 연 소과정에 대해서도 피스톤요부의 벽면에 충돌하는 분무의 각도를 변화시켜, 고속도 화 염사진으로 부터 검토했다.

• The Plant Pathology Journal
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• 제22권4호
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• pp.318-322
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• 2006

One hundred and nine Agrobacterium isolates were recovered from 68 samples(51 plant tumor and 17 soil) that were collected from different habitats in Northern Jordan. The isolated cultures were grouped into 3 biovars based on their biochemical characteristics and biovar I, II, and III comprised a total number of 46, 41, and 22 isolates, respectively. Isolates of biovar I were obtained primarily from the diseased peach, oak and rose plants, whereas isolates of biovar II and ill were obtained mostly from apple and grape plants, respectively. Twenty-nine isolates were found to be virulent to at least one of the tested hosts such as carrots, chickpeas, garden peas and tomato plants with a response of tumor formation or tumor with roots induction. Our result suggested that A. tumefaciens strains from tumor of various plants and soil of Jordan were diverse and they have a variation in their virulence.

• 식물조직배양학회지
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• 제22권2호
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• pp.101-104
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• 1995

작약동아의 정아 및 액아의 기내배양에 의한 유묘의 증식에 필요한 배양조건을 구명코자 실험한 결과는 다음과 같다. 정아배양의 경우, 생장조절재의 조성에 무관하게 두지방종에서 100% 신초가 신장하였으나 생장은 의성지방종 은 NAA 0.1 mg/L 단용배지, 영천지방종은 NAA 0.01 mg/L 단용배지에서 가장 양호하였다. 액아배양의 경우, NAA 0.01 mg/L와 zeatin 5.0 mg/L 혼용배지에서 의성지방종은 100%, 영천지방종은 50%의 가장 높은 신초신장율을 보였고 신초의 생장도 양호한 경향이었다. 정아 및 액아배양으로부터 유도된 신초는 vermiculite를 지지물로 한 NAA 0.1 mg/L 첨가배지에서 30.0%의 발근율을 보였으나 뿌리의 생장은 양호하였다.

• 한국식물병리학회지
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• 제14권6호
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• pp.654-660
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• 1998

Colletotrichum gloeosporioides and Glomerella cingulata are the most important pathogens causing anthracnose which may reduce the stand rate and yield on wide kinds of plants including strawberry. Average occurrence rate of anthracnose is 36.9% on major strawberry cropping areas in Korea. We newly found that C. gloeosporioides which does not forming a sexual stage, infects strawberry and differs in some characteristics concerning virulence, cultural and morphological properties to G. cingulata which has a sexual stage. C. gloeosporioides was mainly isolated from the crown with 35.2% rate, while G. cingulata was largely isolated from petiole, runner with 40.9% rate in infected strawberry plants. These two pathogens showed significant differences in cultural characteristics such as perfect stage formation, temperature response as well as benomyl resistance. It was demonstrated that C. gloeosporioides has significantly stronger pathogenicity than G. cingulata in pathogenicity test carried on strawberry plants to various strawberry cultivars. Akihime, Akaneko and Nyoho forcing cultured strawberry cultivars, considered to be susceptible, while semiforcing cultured cultivars, such as Suhong and Holowase, were shown resistant to both pathogens. In non-wound inoculation, C. gloeosporioides was shown pathogenicity on the apple fruit, but G. cingulata could not infect it.

• 원예과학기술지
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• 제33권1호
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• pp.31-38
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• 2015

This study was carried out to investigate the relationship between endogenous polyamines (PAs) and floral bud differentiation in chrysanthemum (Chrysanthemum morifolium). In this study, PA content (free, bound, and conjugated) in apical buds, leaves, and roots changed appreciably during floral bud differentiation. PAs accumulated during series of processes such as floral induction, differentiation of floret primordia, and crown formation in apical buds; changes in PAs in apical buds may have a relationship with those in leaves and roots. The levels of free PAs and conjugated PAs [putrescine (Put) and spermine (Spm)] in apical buds rapidly increased during the initiation stage of floral bud differentiation, while free and conjugated spermidine (Spd) reached their highest levels at the stage of floret primordium differentiation. In the free, conjugated, and bound PA fractions, the changes in Spm content were negligible compared to those of Put and Spd throughout the experiment. These findings indicate that PAs participate in regulating the process of flower bud differentiation in chrysanthemum.

• International Journal of Oral Biology
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• 제48권4호
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• pp.33-44
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• 2023

In this review, the regulatory mechanisms of autophagy were described, and its interaction with apoptosis was identified. The role of autophagy in embryogenesis, tooth development, and cell differentiation were also investigated. Autophagy is regulated by various autophagy-related genes and those related to stress response. Highly active autophagy occurrences have been reported during cell differentiation before implantation after fertilization. Autophagy is involved in energy generation and supplies nutrients during early birth, essential to compensate for their deficient supply from the placenta. The contribution of autophagy during tooth development, such as the shape of the crown and root formation, ivory, and homeostasis in cells, was also observed. Genes control autophagy, and studying the role of autophagy in cell differentiation and development was useful for understanding human aging, illness, and health. In the future, the role of specific mechanisms in the development and differentiation of autophagy may increase the understanding of the pathological mechanisms of disease and development processes and is expected to reduce the treatment of various diseases by modulating the autophagic phenomenon.

• 대한소아치과학회지
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• 제29권4호
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• pp.607-617
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• 2002

연령과 치아 발육상태 단계와의 상관관계, 치아의 발육에 따른 치아의 이동상태를 평가하기 위하여 최근 5년 이내에 경북대학교 병원에 내원한 아동(남아 446명, 여아 326명)의 파노라마 방사선사진을 대상으로 하여, Moorrees의 기준에 의하여 하악 영구치아의 발육단계를 평가한 후, 발육단계와 연령, 치조골내 치아의 위치를 평가하여 다음과 같은 결론을 얻었다. 치아의 발육시기는 치관이 완료될 때까지 남, 여의 차이가 없었으나, 치근형성이 되면서 부터는 남아보다 여아에서 더 빨리 발육되는 경향을 나타내었다. 치관형성의 완료시점의 평균연령은 남아 여아 각각에서 중절치 3.71, 4.05세, 측절치 4.44, 4.60세, 견치 5.35, 5.11세, 제1소구치 6.62, 6.36세, 제2소구치 7.36, 7.17세, 제1대구치 3.51, 3.69세, 제2대구치 7.90, 7.64세 이었고, 치근단이 폐쇄되기 전단계인 $A_{1/2}$는 중절치 8.70, 8.18세, 측절치 9.55, 8.99세, 견치 12.48, 11.60세, 제1소구치 12.30, 12.01세, 제2소구치 12.19, 12.26세, 제1대구치 912, 8.87세, 제2대구치 12.59, 12.45세 이었다. 치조골내의 교두점 위치는 치관형성 완료시까지는 거의 변화가 없었으나, 치근이 형성됨에 따라 빠르게 교합평면을 향해 이동하였고, 치근형성 완료단계(Rc)에서 다시 움직임 없이 정체되었다. 치근단의 위치는 치관형성 시작부터 치근 1/4 형성 시까지 일정한 위치에 유지되었으나, 그 후에 급격하게 교합면 쪽으로 이동하였고, 치근 3/4 형성시점부터 비교적 일정한 위치에 유지되었다. 치아의 석회화가 시작되는 초기의 치배 위치는 견치가 가장 하방에 위치하였으며, 그 다음이 제2소구치, 제1소구치, 측절치 제2대구치, 제1대구치 순이었고, 중절치가 가장 상방에 위치하였다.

• 대한소아치과학회지
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• 제38권3호
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• pp.290-295
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• 2011

치아형성 과정 중 치배 주위의 물리적 작용이나 대사 환경의 변화로 치아 발생은 영향을 받을 수 있다. 유치열기에 가해진 외상은 계승 영구치의 발생에 장애를 초래시킬 수 있는 가장 대표적인 물리적 요인으로 이로 인한 합병증으로 계승 영구치의 법랑질 변색 및 저형성증이 가장 흔히 발생하고 드물게 매복, 이소 맹출, 치근 형성 정지 및 치근 만곡 등이 나타난다. 본 증례에서는 만 6세 5개월의 여자 어린이 환자가 안면부 외상을 주소로 내원하여 상악 좌우 유중절치의 정출성 탈구, 상악 우측 유측절치의 함입성 탈구, 상악 좌측 유측절치의 구개측 측방 탈구로 진단되었고, 상악 치은부의 열상과 상악 전치부의 치조골 골절이 관찰되었다. 내원 당일 치과 응급실에서 동요도가 심한 상악 좌우 유중절치의 발치 후 치은 봉합술을 시행하였다. 24개월 정기 검진 중 방사선 사진 상에서 상악 좌,우측 측절치의 백악 법랑 경계(Cemento enamel junction, CEJ) 근방에 치근 만곡이 관찰되었고 상악 중절치 치근의 치관부 1/3부위에서 치근 형성이 정지되고 있는 양상이 관찰되었다. 치조골 골절이 어린이에서 흔하게 나타나는 외상의 유형은 아니나 본 증례에서와 같이 치근 발육이상 등 여러 합병증을 일으킬 수 있으므로 외상을 입은 환아에서 치조골 골절 여부에 대한 면밀한 검사 및 주기적인 검진은 예후 예측 및 향후 치료에 있어서 중요할 것이다.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.219-237
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• 1998

Numerous bone graft materials have been used in Periodontics, in an attempt to reach the main goal of periodontal therapy, i.e. the regeneration of periodontal tissue lost due to destructive periodontal diseases. The present study investigates the effect of composite graft of DFDB and Calcium sulfate with and without Calcium sulfate barrier in Periodontal 1-wall intrabony defects in dogs. Following the initiation of general anesthesia by I.V. administration of 40mg/Kg of Pentobabital, second premolar was extracted and full thickness flap elevated. The crown portion of premolars was removed. Exposed root canals were sealed with Caviton and covered completely with flap. After the healing period of 8 weeks, the surgical sites were re-opened and 1-wall intrabony defects were created, and treated with flap operation alone(control group), with composit graft of 80% DFDB and 20% Calcium sulfate(Experimental group 1), with composite graft of DFDB and calcium sulfate with calcium sulfate membrane( Experimental group 2). Healing response was histologically observed after 8 weeks and the results were as follows : 1. New bone formation was 70 % in the control group, 93 % in the Experimental group I, 89 % in the Experimental group II. There was a no differences between Experimental groups. 2. New cementum formation was not significantly different between control and two Experimental groups. 3. The length of connective tissue adhesion was 30 % in the control, 7% in the Experimental group I and 11 % in the Experimental group II. 4. After 8weeks, calcium sulfate was completely resorbed, while DFDB particle remained. These results suggest that the use of composite graft of allogenic DFDB and Calcium sulfate with and without Calcium sulfate barrier in periodontal 1 wall intrabony defects have little effect on connective tissue adhesion, but has beneficial effect on new alveolar bone and new cementum formation, and prevent downgrowth of epithelium and connective tissue effectively.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.