• 한국작물학회지
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• 제43권3호
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• pp.161-167
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• 1998

Root and shoot development of two rice (Oryza sativa L.) cultivars with different genetic backgrounds was studied with reference to their relative growth. Tongil type (indica-japonica hybrid) cultivar 'Kuemkangbyeo' and japonica cultivar 'Koshihikari' were grown in $5000^{-1}$ a Wagnar pots under flooded condition. Three plants with roots of both cultivars were taken in every phyllochron through the heading stage to record morphological characteristics of shoot and root system. Compared to Koshihikari, Kuemkangbyeo produced more tillers and had greater shoot weight and leaf area per hill. Length and weight of the root system in both cultivars increased exponentially with time. At the same time, root system development was significantly faster in Kuemkangbyeo than in Koshihikari after the panicle initiation stage. As a result, Kuemkangbyeo has a vigorous root system which consists of larger number of nodal roots compared to Koshihikari. Also, the root length and weight per unit leaf area of Kuemkangbyeo were larger than those of Koshihikari in the later half of growing period, which suggests possible higher physiological activity of the root system of Kuemkangbyeo which is known as a high-yielding cultivar. The relationship between root traits (crown root number, total root length, and root dry weight) and shoot traits (leaf area and leaf+culm dry weight) in both cultivars closely showed allometry until the flag leaf stage.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.103-103
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• 2017

Vigorous root growth at the seedling stage in dry direct-seeded conditions is considered as a critical trait because it is involved in seedling emergence, early vegetative vigour, nutrient uptake as well as drought tolerance. In this study, we performed QTL mapping using the recombinant inbred lines obtained from the cross between Tongil-type Dasan and temperate japonica TR22183 (DT-RILs) to identify QTL underlying early root development. TR22183, which was previously reported to have high nitrogen utility and cold tolerance, showed vigorous root growth at the seedling stage in semi-drought conditions. Root length, fresh weight and dry weight of TR22183 were significantly higher than in Dasan. By QTL analysis with genotyping-by-sequencing method, we identified two QTLs for root fresh weight (RFW) in chromosome 7 and root dry weight (RDW) in chromosome 8, explaining phenotypic variances of 13.5% and 10.6%, respectively. These QTLs would be used to develop rice varieties adapted to direct-seeded cultivating system.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2019년도 추계학술대회
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• pp.21-21
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• 2019

Approximately 80% of rice field in Africa conducts in rainfed (Nishimaki 2017). The rice is damaged by water stress because fields like rainfed lowland repeat drying and humidity of soil because of impossible water control. Then water stress is one of the major limiting factors for decreasing rice yield. So, in initial growth stage, quick and efficient root development is useful way to avoid drought stress by getting water from deeper soil layer with roots elongation as the hypothesis. Daniel et al (2016) reported that NERICA1 and NERICA4 show different patterns of root plasticity for drought stress. NERICA1 has greater development of lateral root in shallow soil layer, while NERICA4 has greater development in deep root elongation to underground. This study was aimed to evaluate the effect of root development in initial growth stage on growing NERICA1 and NERICA4 under different soil moisture condition in rainfed lowland rice field. They were grown in same water condition until 35 days after sowing (35DAS), and after that each varieties were separated in dry and wet condition. The rice plants were grown until 60DAS. The results of soil moisture, the root extension angle, shoot dry weight and bleeding ratio showed that NERICA4 can mitigate dry stress from surface soil compered to NERICA1.

• 원예과학기술지
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• 제33권2호
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• pp.166-176
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• 2015

본 연구는 USGA 지반으로 조성된 연구포장에서 조성단계별 주요 한지형 잔디의 뿌리생육 특성 차이 파악 및 스포츠 잔디설계, 시공 및 관리에 필요한 기본 정보를 수집하고자 수행하였다. 공시초종은 켄터키 블루그래스, 퍼레니얼 라이그래스, 톨 페스큐와 이들 한지형 혼합구 세 종류로 전체 6종류이었다. 본 실험결과 한지형 초종별 뿌리생장, 뿌리활착도 및 근계발달에 대해 유의한 차이가 나타났다. 전반적으로 뿌리생장, 뿌리활착도 및 근계발달은 조성 후 시간이 지남에 따라 증가하는 경향이었으며 조성단계에 따라 차이가 크게 나타났다. 조성 초기 단일 초종 간 뿌리생장은 퍼레니얼 라이그래스 > 톨 페스큐 > 켄터키 블루그래스 순서로 나타났다. 조성 중기 뿌리생장은 조성 초기와 비슷한 경향이었지만, 전체적인 뿌리생장은 초기에 비해 13-31% 정도 낮게 나타났다. 그리고 조성 후기 뿌리생장은 조성 중기에 비해 34-85% 정도 크게 증가하였으며 혼합구 I을 제외한 대부분 초종의 뿌리길이가 22cm 전후로 비슷하였다. 뿌리활착도는 경시적인 차이가 있었지만, 초종 간 우열관계는 조성단계에 따라 다르게 나타났다. 즉 조성 초기 단일 초종구의 뿌리활착도는 퍼레니얼 라이그래스 > 켄터키 블루그래스 > 톨 페스큐, 조성 중기에는 퍼레니얼 라이그래스 > 톨 페스큐 > 켄터키 블루그래스, 그리고 조성 후기에는 톨 페스큐 > 퍼레니얼 라이그래스 > 켄터키 블루그래스 순서로 나타났다. 잔디밭 조성이 완료된 시점 초종간 근계발달 범위는 톨 페스큐 > 퍼레니얼 라이그래스 > 켄터키 블루그래스 순서로 나타났다. 종합적으로 뿌리생장, 뿌리활착도 및 근계발달 특성을 고려 시 한지형 잔디의 지하부 뿌리생육 특성은 톨 페스큐가 가장 우수한 초종으로 판단되었으며, 혼합구의 뿌리생육 특성은 초종 및 혼합정도에 따라 다양하게 나타났다. 초종별 뿌리생육 특성 차이는 발아속도, 생육습성 및 유전적 특성 때문에 나타나는 것으로 판단되었다. 즉, 톨 페스큐는 조성 후 시간이 경과할수록 뿌리생장, 특히 근계발달 형성능력이 우수하게 나타났으며, B-type 퍼레니얼 라이그래스는 조성 초기 뿌리생장이 우수하였지만, 조성 후기로 갈수록 근계발달 능력이 저조한 경향으로 나타났다. R-type 켄터키 블루그래스는 초기 뿌리생장은 저조하였지만, 조성 후기 활착이 진행될수록 뿌리생장 및 근계발달 능력이 양호하게 나타났다. 스포츠 잔디밭 설계 및 시공 시 지상부 생육특성과 함께 지하부 뿌리특성도 함께 고려해서 컨셉에 적합한 잔디밭 조성이 중요한데 본 연구에서 밝혀진 한지형 잔디의 조성단계별 뿌리생장, 뿌리활착도 및 근계발달 특성은 실무에 유용하게 활용될 것이다.

• Journal of Oral Medicine and Pain
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• 제17권2호
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• pp.119-128
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• 1992

In order to evaluate the relationship of age with the developmental stage on mandibular second molars in female, the author examined the radiographs in standard films taken by intraoral paralleling technic and analysed the development of 620 roots of 310 females ranged from 10 to 18 years. The development was divided into 7 stages : Crown complete (Cr.C.), Root lengthed 1/4(R.1/4), Root length 1/2 (R.1/2), Rooth length 3/4 (R.3/4), Rooth length complete (R.C), Apex 1.2 closed (A. 1/2), Apical closure complete (A.C) The obtained results were as follows : 1. The formation of roots in fulllength of mandibular second molars was completed at 14.21-year-age in mesial root and at 14.96-year-age in distal root. 2. The formation of apical foramen of mandibular second molars was completed at 17.11-year-age in mesial root and at 17.53-year-age in distal root. 3. The mesial root of mandibular second molar was generally developed earlier than distal root (p<0.01) 4. Coefficients of correlation and regression equations between for age(Y) and the developmental stage of mandibular second molar(X) were "Y=1.53X+6.54, r=0.91 (p<0.01)" in mesial root and "Y=1.52X+7.11, r=0.92(p<0.01)" in distal root respectively.l root respectively.

• International Journal of Oral Biology
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• 제36권3호
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• 한국작물학회지
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• 제42권2호
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• pp.146-152
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• 1997

Development of shoot and root, leaf water potential and photosynthetic rate affected by water stress in early growing stage of tobacco were surveyed to interpret stress response in terms of plant physiological and agricultural aspects. The growth of shoot and root was highly suppressed by water stress and the difference in dry weight by rewatering was smaller in root than in shoot. The total root length was highly decreased by water stress and the lengths of root for water stress and non-stress were 74m and 84m, respectively, after rewatering. The root growth treated by water stress was increased between 2nd and 3rd day after treatment indicating that temporary water stress at early growing stage might have increased of root zone activity for early growth stage. The leaf water potentials were decreased to -7.63MPa, -9.47MPa, -11.89MPa, -13MPa at the 2nd, 3rd, 4th and 5th day by water stress. The relative water contents were 75%, 62% and 57% at the 3rd, 4th and 5th day after treatment. Photosynthesis was reduced largely by water stress. The photosynthetic rate after treatment at 2nd day and 3rd day was dropped to 18.15$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$ and 9.35$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$. It was never recovered to the normal, even after rewatering. Stomatal conductance had been reduced since 2nd day after treatment and increased after rewatering.

• 대한소아치과학회지
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• 제48권4호
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• pp.449-459
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• 2021

이 연구는 재생근관치료 결과에 영향을 줄 것으로 예상되는 인자를 후향적으로 분석하였다. 2011년 2월부터 2020년 1월까지 외상과 치외치 파절로 항생제 복합제제를 사용하여 재생근관치료를 시행한 54명의 환자와 57개의 치아를 대상으로 하였다. 의도적 출혈 여부, 치료원인, 치근발육단계에 따른 재생근관치료 결과를 분석하였다. 치료 결과는 증상의 개선, 치근단병소의 변화, 치근성장량을 토대로 판단하였다. 영상 촬영각도 및 위치에 의한 왜곡을 보정하기 위해 Turboreg plugin을 사용하였고, ImageJ softeware상에서 치근단공 크기, 치근면적, 치근길이의 변화를 측정하였다. 의도적 출혈 유무는 치료 결과에 유의한 영향이 없었다. 외상으로 인한 경우 치외치 파절로 인한 경우보다 치근면적과 치근길이의 증가가 적었다. 치근발육이 덜 진행된 치아일수록 치근면적의 성장이 크게 나타났다.

• 한국정밀공학회지
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• 제28권6호
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• pp.738-744
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• 2011

The reliability of blade root fixing section is required to endure the centrifugal force and vibration stress for the last stage blade of steam turbine in thermal power plant. Most of the domestic steam turbine last stage blades have finger type roots. The finger type blade is very complex, so the inspection had been performed only on the exposed fixing pin cross-section area due to the difficulty of inspection. But the centrifugal force and vibration stress are also applied at the blade root finger and the crack generates, so the inspection method for finger section is necessary. For the inspection of root finger, inspection points were decided by simulating ultra-sonic path with 3D modeling, curve-shape probe and fixing jig were invented, and the characteristics analysis method of ultrasonic reflection signal and defect signal disposition method were invented. This invented method was actually executed at site and prevented the blade liberation failure by detecting the cracks at the fingers. Also, the same type blades of the other turbines were inspected periodically and the reliability of the turbine increased.

• Journal of Oral Medicine and Pain
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• 제6권1호
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• pp.23-34
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• 1981

In order to evaluate the correlation of age with development stage on permanent lower posterior teeth. the author exmined the roentgeregrams in standard films taken by intraoral technic and analysed the development phases of 1358 teeth of 500 males ranging from 9 to 15 years. The development was divided into 7 phases : Crown complete (Cr. C.). Root length 1/4(R. 1/4) Root length /2 (R. 1/2) Apical closure complete (A.C) The obtained results were as follows : 1. The formation of roots in full length on posterior teeth was complete as follow : a. Roots of 1st premolar : 12.72 years b. Roots of 2nd premolar : 12.94 years c. Meral Roots of 2nd molar : 13.38 years d. Distal Roots of 2nd molar : 13.46 years 2. The formation of apical forman of premolar was closured as follows : a. Apical foramen of root of 1st premolar : 13.64 years b. Apical foramen of root of 2nd premolar : 13.93 years 3. As a general rule. the mesial roots of second molar were developed earlier than distal roots of second molar. 4. In the correlation of age with the development stage, the regression equations. the correlation coefficents. and the sample numbers were “Y = 0.8370x + 10.2160, r = 0.71(p<0.01), n = 318”on lower first premolar, “Y = 0.6984x + 10.2148, r = 0.71(p<0.01), n = 385”on lower second premolar, “Y = 0.8810x + 10.2040, r = 0.65(p<0.01), n = 344”on mesial Root of lower second molar, and “Y = 0.7310x + 10.7940, r = 0.66(p<0.01), n = 311”on Distal Root of lower second molar respectively.