• 한국환경복원기술학회지
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• 제16권3호
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• pp.83-95
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• 2013

To understand natural regeneration and stand development after fire in mixed broadleaved-coniferous forests of Sikhote-Alin Mountains, ten sample plots of $50m{\times}50m$ size were established in 1975 and 1983 at the stands burned by wildfires in 1973 and 1982, respectively. And, the number of naturally regenerated seedlings were monitored in two $50m{\times}4m$ subplots in each plot. The most fire-sensitive conifer species is Abies nephrolepis, while Betula costata is the most fire-sensitive broadleaved tree species. The most fire-resistant species were Q. mongolica, T. taquetii and A. mono. The results of 20 and 30 years after the fire showed that pioneer tree species, e.g. Populus, Salix, and Betula, were regenerated immediately at the early stage of stand development and grew where there is a mono canopy layer with high density. On the other hand, the densities of successors, e.g. Pinus koraiensis, Picea jezoensis, Abies nephrolepis, Acer mono and Tilia taquetii, which were present in the study plots before the fire, increased gradually. Naturally regenerated tree species after forest fire by the growth rate were divided into three groups according to their annual height growth. The seral tree species (Betula costata, Betula platyphylla, Padus maackii, Populus tremula and Sarix caprea) belong to the first group and have the highest growth rate (from 40 to 96 cm per year). The late successional broad-leaved trees (Tilia taquetii, Acer mono and Quercus mongolica) belong to the second group and have intermediate annual height growth (from 3.7 to 13.5 cm per year). The late successional coniferous species (Picea jezoensis, Pinus koraiensis and Abies nephrolepis) form the third group and have the least annual height growth (from 1.4 to 3.5 cm per year).

• 농업생명과학연구
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• 제45권4호
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• pp.47-58
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• 2011

The forest of Korea had been severely degraded since early 1900s until 1950s. Korean Government has successfully accomplished the reforestation works since 1960s. However, some plantations showed poor survival and growth caused by ignoring site characteristics in selecting plantation species and lack of tending works such as thinning. The natural regeneration of indigenous species, such as Quercus species and Pinus densiflora Siebold & Zucc., were examined in the plantations of Pinus koraiensis Siebold & Zucc. and Larix kaempferi Fortune ex Gordon. Quercus species regenerated mainly by sprouting while P. densiflora regenerated naturally from a few mother trees that remained in the plantations. P. koraiensis showed poor survival ($IVI{\leq}25%$) and suppressed growth (height ${\leq}3m$ and $DBH{\leq}3cm$ at 20 year-old) by Quercus species or P. densiflora in the plantation areas, however had high survival ($IVI{\geq}70%$) and growth (8 m height and 14.1 cm DBH at 20 year-old) in areas where silvicultural practices were conducted. L. kaempferi showed good survival ($IVI{\geq}40%$) and growth (17.2 m height and 16.3 cm DBH at 30 year-old) mostly in valley areas, while it was nearly dead ($IVI{\leq}10%$) in ridge or ridge-slope areas and was replaced by indigenous species such as Quercus species ($IVI{\geq}25{\sim}55%$) or P. densiflora ($IVI{\geq}18{\sim}50%$).

• 혜화의학회지
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• 제28권2호
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• pp.41-47
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• 2019

Objectives : Atopic dermatitis is an irritable skin disease accompanying rash and itching leading to impaired skin barrier. ATO-ALL is an ethanol extract of natural products comprising 12 herbs and effective on atopic dermatitis. In this study, we aimed to propose that the effect of ATO-ALL on skin regeneration in human keratinocyte cell line, HaCaT cells. Methods : To evaluate the skin regenerating effects of ATO-ALL, scratch wound healing assay, bromodeoxyuridine (BrdU) assay, and propidum iodide (PI) assay were performed using cultured HaCaT cell line. Result : Scratch wound healing assay showed that ATO-ALL was able to enhance the gap filling activity more than 2-fold at 7 ppm concentration compared with control group. BrdU assay demonstrated that ATO-ALL treatment increased the de novo cell proliferation in a dose-dependent manner. Finally, PI assay indicated that the cell cycle of HaCaT cells was modulated by ATO-ALL treatment. Conclusions : These results suggested that ATO-ALL may have skin regenerating effects by increasing cell proliferation via cell cycle regulation. Taken together, ATO-ALL is supposed to have a potential on regeneration of damaged skin or functional disease including atopic dermatitis.

• Journal of Periodontal and Implant Science
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• 제30권3호
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• pp.553-569
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• 2000

Many natural medicines have been studied for their capacity and effects of antibacterial, anti-inflammatory and regenerative potential in periodontal tissues. Safflower seed has been traditionally used as a drug for treatment of bone fracture in oriental medicine. The purpose of the present study was to compare the effects of safflower seed extract and bone substitute on bone formation and regeneration in artificial defects in mongrel dogs. The bony defects were made with round bur at mandible and tibia. Extracts of safflower seed and bovine bone were placed directly at each defect for experimental group, and the defect of control group was sutured without any other treatment. Experimental animals were sacrificed at 8 weeks. And then histopathologic reading and histomorphometric study was done. There was not significant differences between control and experimental groups in osteoclastic activity and infiltration of inflammatory cells. However, new capillary proliferation, fibrosis and new bone formation were prominent in safflower seed extract group. The mandibular defects of safflower seed extract group were healed with dense connective and bony tissues, and endochondral bone formation was observed in tibial defect of safflower seed extract group only. New bone area of safflower seed extract group was more significantly increased than that of control and that of bone substitute group. These results indicate that direct local application of safflower seed extracts on bony defects seems to reduces the early inflammatory response and to promotes the bone regeneration.

• 한국산림과학회지
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• 제84권2호
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• pp.258-265
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• 1995

본(本) 연구(硏究)는 경상북도(慶尙北道) 울진군(蔚珍群) 불영계곡 일대(一帶)에서 토지극상(土地極相)을 형성(形成)하고 있는 소나무림(林)을 대상(對象)으로 임분(林分)의 재생(再生) 과정(過程)을 밝히고자 하였다. 소나무 임분(林分)은 수고(樹高)가 12-5m 정도(程度)이며, 상층목(上層木)은 개체(個體)가 중심(中心)이 되어 임의적으로 분포(分布)하고 있으며, 하층목(下層木)은 집중반(集中斑)으로 분포(分布)하고 있다. 상층목(上層木)은 주로 60-80년(年) 정도(程度)의 정점을 갖는 단봉형(單峰型)의 분포(分布)를 나타내고 있으며, 이들 임분(分布)의 수평적(水平的) 분포(分布)는 대체로 동령적(同齡的) 집단(集團)을 보여주고 있다. 상층목(上層木)의 초기(初期) 25년(年) 동안의 비대생장(肥大生長) 속도(速度)는 중(中) 하층목(下層木) 보다 빠르다. 소나무림(林)의 재생(再生) 과정(過程)은 임내(林內)에 gap이 형성(形成)된 이후(以後)에 집중적(集中的)으로 발생(發生)한 후생(後生)한 추수(推樹)가 성장(成長)하여 그 중(中)의 몇 개체(個體)가 임관(林冠)을 형성(形成)하는 것으로 추정(推定)된다.

• Journal of Plant Biotechnology
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• 제36권2호
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• pp.193-196
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• 2009

Pinellia koreana K-H Tae & J-H Kim is a recently discovered Korea endemic medicinal plant species whose natural habitat is rapidly destroyed by industrial development. Described in this paper are culture conditions for high frequency plant regeneration via bulblet formation from leaf explant cultures of P. koreana. Leaf explants formed white nodular structures and off-white calluses at a frequency of 91.2% when cultured on MS medium supplemented with 2 mg/L BA and 0.5 mg/L NAA. However, the frequency of white nodular structures and off-white calluses formation was slightly decreased with an increasing concentration of NAA up to 4 mg/L, where the frequency reached 31.7%. Most petiole explants did not form white nodular structures and off-white calluses except the combination treatment of 2 mg/L BA and 2 mg/L NAA. Upon transfer onto MS basal medium, over 90% of nodular structures gave rise to numerous bulblets and developed into plantlets. Plantlets regenerated from bulblets were transplanted to potting soil and grown to maturity at a survival rate of over 95% in a growth chamber. Therefore, the in vitro plant regeneration system of P. koreana obtained in this study will be useful for mass propagation and long-term preservation of genetic resources of P. koreana.

• Journal of Forest and Environmental Science
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• 제34권4호
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• pp.338-351
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• 2018

This study was conducted in a long-term experimental forest in the central hardwoods region of southwestern Michigan to retrospectively examine the role of past forest management practices and climate on red oak (Quercus rubra L.) productivity. Initially, in 1971, plots within the experimental forest were treated separately with a clearcut and shelterwood regeneration harvest in an attempt to increase red oak regeneration. From 1987-1989, a new study was initiated within a portion of the clearcut and shelterwood plots to evaluate the effectiveness of additional oak crop tree release using mechanical and chemical applications. Cumulative diameter and mortality rates of 719 red oaks were monitored across the four silvicultural treatments: Clearcut-A (clearcut without additional release treatment), Clearcut-B (clearcut with additional release treatment), Shelterwood-A (shelterwood without additional release), and Shelterwood-B (shelterwood with additional release) plus an untreated control. Increment cores were obtained from red oak trees and neighboring competitor species. Tree-ring analyses (dendrochronology) were applied to examine the effect of these silvicultural treatments and climatic factors (temperature and precipitation) on red oak productivity. The results indicated that crop tree release following a clearcut or shelterwood harvest reduced mortality rates and thus increased survival of red oak. Red oak in control plots or plots only receiving the initial regeneration harvesting treatment and no additional competition release were negatively affected by climatic stress, which included summer moisture stress. In contrast, red oak in plots that received the competition release treatment from shade tolerant tree species not only had higher tree level productivity (i.e., tree basal area) and lower mortality rates, but were also relatively more resilient to climatic stress by showing limited or no associations between climate and growth.

• The Korean Journal of Ecology
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• 제18권1호
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• pp.189-201
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• 1995

In order to clarify regeneration processes and mechanisms of the disturbed Pinus densiflora forest, responses of Pinus densiflora to gap formed by disturbance were analysed by growth of saplings and mature and growth equations were obtained from branch growth of mature trees and height growth of saplings, and age distribution of saplings and young trees recruited within gap was analysed in relation to gap age. Height growth of saplings within gaps was accelerated after gap formation. Such abrupt increases of growth of saplings after the gap formation might be resulted in the difference of growth of saplings between gap and non-gap areas. In fact, height and diameter of saplings in the central part of gap were larger than those of saplings in marginal parts of gap and non-gap area. However, density of saplings was not different in both parts. In addition, growth of annual rings of mature trees bordering on gap also increased after gap formation. Branch growth of mature trees bodering on gap was 6.3 - 6.5 cm /year and the mean radius of gaps created by death of only one canopy tree was about 3 m. Therefore, for those gaps to be closed by branch growth it will take 46 years. Growth of saplings within gap showed exponential equation. Fifty years will be required for the saplings to enter the forest canopy by the exponential growth equation. Therefore, gap created by only one tree might be closed by branch growth of surrounding canopy trees in advance of being done by height growth of saplings. But gaps created by death of trees more than 2 will be closed by the growth of saplings. Among the regenerating saplings and young trees within gaps, individuals established in advance of gap formation were more than those established after the gap formation. From these results, it was assumed that the disturbed Pinus densiflora forests in these sites were regenerated by height growth of saplings recruited in advance of gap formation.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.15-15
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• 2019

The walnut (Juglans regia L.), a member of the Juglandaceae, is native to the mountain ranges of central Asia. This species of walnut is valued commercially for its nuts and in some areas for its timber. The seeds of walnut are recalcitrant and it has strong integument dormancy and their germination is irregular, making its natural propagation difficult. Low percentage of seed germination and long propagation cycle are the main problems of propagation. This study was conducted medium composition on in vitro plantlet regeneration from axillary buds of walnut. It has proved to be the most generally applicable and reliable method of in vitro propagation. Micropropagation culture that axillary buds are excised aseptically enables faster multiplication of plants. The axillary buds of walnut new cultivar "Sinlyeong" were cultured on two basal media which contained the different plant growth regulators depending on the respective shooting and rooting stage. After 12 weeks, the shoot generation rate was 85.3%, the shoot number and its length were 1.9/explant and 2.7 cm in the most favorable medium composition. The percentage of rooting was 25.4%. From these results, it was found the optimum basal medium and plant growth regulator for in vitro plant regeneration from axillary buds of walnut new cultivar "Sinlyeong". However, we have continued to search the other medium additives to enhance the rate of walnut root.

• 대한치과교정학회지
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• 제49권5호
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• pp.299-309
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• 2019

Objective: This study aimed to investigate the effect of pre-applied orthodontic force on the regeneration of periodontal ligament (PDL) tissues and the underlying mechanisms in tooth replantation. Methods: Orthodontic force (50 cN) was applied to the left maxillary first molars of 7-week-old male Sprague-Dawley rats (n = 32); the right maxillary first molars were left untreated to serve as the control group. After 7 days, the first molars on both sides were fully luxated and were immediately replanted in their original sockets. To verify the effects of the pre-applied orthodontic force, we assessed gene expression by using microarray analysis and real-time reverse transcription polymerase chain reaction (RT-PCR), cell proliferation by using proliferating cell nuclear antigen (PCNA) immunofluorescence staining, and morphological changes by using histological analysis. Results: Application of orthodontic force for 7 days led to the proliferation of PDL tissues, as verified on microarray analysis and PCNA staining. Histological analysis after replantation revealed less root resorption, a better arrangement of PDL fibers, and earlier regeneration of periodontal tissues in the experimental group than in the control group. For the key genes involved in periodontal tissue remodeling, including CXCL2, CCL4, CCL7, MMP3, PCNA, OPG, and RUNX2, quantitative RT-PCR confirmed that messenger RNA levels were higher at 1 or 2 weeks in the experimental group. Conclusions: These results suggest that the application of orthodontic force prior to tooth replantation enhanced the proliferation and activities of PDL cells and may lead to higher success rates with fewer complications.