• Journal of Ginseng Research
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• 제16권1호
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• pp.31-36
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• 1992

The ultrastructural changes and differentiation mechanism of chromoplasts and leucoplasts from Proplastids in root tip cells of Panax ginseng seedlings were studied with transmission electron microscope. Initial cells have so many proplastids with a few osmiophilic droplets and a lot of mitochon dria at early stage of germination, therefore electron density of cytoplasm is generally higher than that of the other cells just like periblem, plerome and root cap. Proplastids are observed in the initial cells, but only leucoplasts appeared in the central root cap cells. Because root cap cells are derived ultimately from initial cells, the cell organelles in the root cap cells are directly related by those of initial cells. This result postulates that leucoplast is diferentiated from proplastid, and this is the same with other's concepts. On the contrary, the precise observations of chromoplast with crystalline inclusions in the peripheral root cap cells can conclude the direct pathway of chromoplast development from proplastid. Because of the differences of these result from those of other experiments, new scheme of plastid development, direct differentiation of chromoplast from proplastid, can be postulated. And this is the originality of this research on the differentiation of plastids.

• 대한치과교정학회지
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• 제28권4호
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• pp.591-600
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• 1998

본 연구는 교정치료를 목적으로 발치가 예정된 치아를 대상으로 임상적으로 매우 중요한 치료과정 중의 한 부분인 초기치아배열단계에서 다양한 기간과 크기의 교정력을 가하여 치아배열기간, 교정력의 크기,치아이동방향에 따라 치근표면에 일어나는 흡수와 회복 양상에 대한 정보를 얻기 위하여 시행되었다. 치료받지 않은 13개의 치아를 대조군으로 하고 교정치료계획상 제1소구치를 발거하기로 예정된 37개의 치아를 실험군으로 하여 20-450gm의 초기교정력을 가한 후 주사전자현미경적 관찰을 통하여 다음과 같은 결과를 얻었다. 1. 실험군 37개 중 22개의 치아($59.5\%$)에서 치근흡수가 발견되었다. 치근흡수는 최소실험기간인 3주군부터 나타났으며 흡수부위의 회복은 3개월군부터 나타났다. 2. 교정력의 기간 증가에 따라 치근흡수의 발생빈도가 증가하는 경향을 보였다. 3. 교정력이 클수록 상아질을 포함하는 홉수가 증가하는 경향을 보였다. 4. 치근 흡수의 부위는 하중 받는 부위와 일치하는 경향을 보였다. 5. 치근 흡수 부위의 면적과 가장 상관성이 높은 변수는 교정력의 크기였다.

• 한국자원식물학회지
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• 제26권6호
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• pp.709-717
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• 2013

The objective of this study was to examine the effect of root pruning intensity in combination with different initial seedling size on the growth of transplanting seedlings of Quercus acutissima. One-year-old seedlings were divided into three groups depending on their height, i.e. small (< 15 cm), medium (25-35 cm) and large size (35 cm <). Root of seedlings was pruned by three intensity such as, leaving 5 cm (severe), 10 cm (medium) and 15 cm (light) of taproot from the root-collar. After one year, we investigated survival rate, height and root-collar diameter (RCD) increment and final shoot dry weight. Also we measured characteristics of newly developed lateral roots such as number, total length, dry weight and diameter. Severe root pruning showed the lowest survival rate in all seedling size. Height increment, RCD increment and shoot dry weight were decreased with increasing intensity of root pruning. Seedlings of medium and light root pruning showed similar above-ground growth and dry weight of lateral roots. More large seedlings showed good survival rate, height increment and final shoot dry mass in all root pruning intensity. Therefore, one-year-old seedlings of Q. acutissima should be pruned taproot by 10 cm and transplanted to obtain excellent performance and increase the efficiency of transplanting work. Based on the findings of this study, it is important that applying to different root pruning intensity depending on initial seedling size for producing 2-year-old seedlings with excellent growth and high quality.

• The Plant Pathology Journal
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• 제24권3호
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• pp.352-356
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• 2008

Root discs of 4-year-old ginseng, Panax ginseng C. A. Meyer, were inoculated with the higher($10^8$ colonyforming units(CFU)/ml) and lower($10^6\;or\;10^5$ CFU/ml) initial inoculum levels of a plant-growth promoting rhizobacterium(PGPR), Paenibacillus polymyxa GBR-1 to examine rot symptom development and bacterial population changes on the root discs. At the higher inoculum level, brown rot symptoms developed and expanded on the whole root discs in which the bacterial population increased continuously up to 4 days after inoculation. In light and electron microscopy, ginseng root cells on the inoculation sites were extensively decayed, which were characterized by dissolved cell walls and destructed cytoplasmic contents. However, no rot symptoms were developed and the bacterial population increased only during the initial two days of inoculation at the lower inoculum level($10^6$ CFU/ml) of P. polymyxa GBR-1. At the lower inoculum level($10^5$ CFU/ml), boundary layers with parallel periclinal cell divisions, structurally similar to wound periderm, were formed internal to the inoculation sites, beneath which the cells were intact containing numerous normal-looking starch granules and no disorganized cell organelles, suggesting that these structural features may be related to the suppression of symptom development, a histological defense mechanism.

• Journal of Periodontal and Implant Science
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• 제39권3호
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• pp.375-381
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• 2009

Purpose: Root resection can be a valuable procedure when the tooth in question has a high strategic value. The prognosis of root resection has been well documented in previous studies, but the results focused on the palatal root resection have not been discussed in depth. I represent here the short term effectiveness of palatal root resection of maxillary first molars. Methods: Palatal root resection was performed on maxillary first molars of three patients. All the palatal roots were floating state on the radiographic finding and showed full probing depth and purulent exudation at initial examination. Reduction of palatal cusp and occlusal table was performed concomitantly. Endodontic therapy was completed after root resection. Results: Compromised maxillary first molars were treated successfully by palatal root resection in 3 cases. The mobility of resected tooth was decreased a little bit. The probing pocket depth of remaining buccal roots was not increased compared to initial depth. All the patients satisfied with comfort and cost effective results and the fact they could save their natural teeth. Conclusions: Within the above results, palatal root resection is an effective procedure treating compromised maxillary first molar showing advanced palatal bone loss to root apex with or without pulp involvement when proper case selection is performed.

• 한국식품영양학회지
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• 제28권5호
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• pp.926-932
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• 2015

This study was conducted to examine the effect of mustard root on the shelf life of kimchi. Ethanol extract was prepared from the mustard root (Brassica juncea) and antimicrobial activities were examined against Lactobacillus plantarum and Leuconostoc mesenteroides which are the representative lactic bacteria in kimchi. Growth of lactic bacteria were inhibited by ethanol extract from mustard root and the growth time of Leuconostoc mesenteroides was delayed more than 24 hours compared with that of Lactobacillus plantarum. Also, the fermentative and sensory characteristics of kimchi with mustard root were evaluated during fermentation at $10^{\circ}C$. The pH and acidity was lower than that of the control kimchi and the fermentation period was retarded in proportion to the increase in mustard content. The total numbers of microorganism and lactic bacteria in the control kimchi were higher than those in kimchi with mustard root during fermentation. Leuconostoc sp. in the initial stage of growth was more inhibited than Lactobacillus sp. While the pH of kimchi were in the initial stage, the sensory evaluation score for savory flavors of the kimchi with mustard root was lower than that of control due to bitterness and pungency. But when the pH of kimchi reached the optimum stage, the scores for texture and savory flavor of kimchi with mustard root were higher than that of the control. Then overall quality score for kimchi with mustard root increased as bitterness decreased.

• 식물병과 농업
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• 제5권2호
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• 대한기계학회논문집
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• 제11권5호
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• pp.740-745
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• 1987

본 연구에서는 파괴조건(4)와 유사하게 임계 스트레인 조건을 사용하나 기존 스트레인이 없는 재료의 날카로운 균열선단을 가진 시편의 파괴인성실험치(.delta.$_{IC}$)로 부터 재료의 고유상수인 특성길이를 결정하는 방법이 제안되었다.이 파괴조건을 이 용하여 처음노치선단의 유한한 반경과 재료의 기존 스트레인이 시편의 파괴개시에 미 치는 영향을 예측하고자 한다.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.371-376
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• 1998

This study presents an evaluation of the effectiveness of nonsurgical subgingival scaling and root planing related to initial pocket depth, type of teeth, and individual root surfaces. A total of 110 teeth designated for periodontal surgery in 67 patients with marginal periodontitis were selected and received thorough scaling and root planing with standard rigid Gracey curettes. After a healing period of 4 to 8 weeks, residual calculus was assessed at the time of periodontal surgery following the reflection of mucoperiosteal flap. The results demonstrated a high correlation between the percentage of residual calculus and initial pocket depth. It was further noted that tooth type and involved root surface also influenced the rate of calculus remnant. The results of this study suggest that complete removal of subgingival calculus utilizing conventional instrumentation via closed approach is rare.

• 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.