• Journal of Periodontal and Implant Science
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• 제49권5호
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• pp.287-298
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• 2019

Purpose: The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure. Methods: Patients who received implant treatment with a single implant system ($Luna^{(R)}$, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively. Results: This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47-61 years) and were followed up for a median of 7.2 months (IQR, 5.6-9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37-5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12-4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05). Conclusions: Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.

• Journal of Plant Biotechnology
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• 제48권4호
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• pp.255-263
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• 2021

Paederia foetida L. is an important medicinal plant that has been used for the treatment of various gastrointestinal related ailments by different tribal communities in India. This plant is also known for its use as a food. Due to overexploitation, P. foetida has been classified as a vulnerable plant in some states of India. The propagation of P. foetida by conventional methods is easy but very slow. Synthetic seed technology offers incredible potential for in vitro propagation of threatened and commercially valuable plants, and can also facilitate the storage and exchange of axenic plant material between laboratories. However, synthetic seed production for P. foetida has not yet been reported. Thus, to the best of our knowledge, the present study is the first attempt to produce synthetic seeds of P. foetida by calcium alginate encapsulation of in vitro regenerated axenic nodal segments. Sodium alginate (3%) and CaCl₂ (100 mM) were found to be the optimal materials for the preparation of ideal synthetic seeds, both in terms of morphology and germination ability. The synthetic seeds showed the best germination (formation of both shoot as well as root; 83.3%) on ½ MS medium augmented with 0.5 mg/L indole-3-acetic acid. The plantlets obtained from these synthetic seeds could be successfully acclimatized under field conditions. We also studied the storage of these synthetic seeds at low temperature and their subsequent sprouting/germination. The seeds showed a germination rate of 63.3% even after 21 days of storage at 4 ℃; thus, they could be useful for transfer and exchange of P. foetida germplasm.

• Journal of the Korean Applied Science and Technology
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• 제35권4호
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• pp.1433-1441
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• 2018

The development of acidosis during intense exercise has traditionally been explained by the increased production of lactic acid which causes the release of a proton and the formation of the acid salt sodium lactate. Through this explanation, when the rate of lactate production is high enough to exceed cellular proton buffering capacity, cellular pH is decreased. This biochemical process has been termed lactic acidosis. This belief has been an interpretation that lactate production causes acidosis and fatigue during intense exercise. However, this review provides clear evidence that there is no biochemical support for lactate production causing acidosis and fatigue. Metabolic acidosis is caused by an increased reliance on nonmitochondrial ATP turnover. Lactate production is essential for muscle to produce cytosolic $NAD^+$ to support continued ATP regeneration from glycolysis. In addition, Lactate production consumes protons. Although lactate accumulation can be a good indirect indicator for decreased cellular and blood pH, that is not direct causing acidosis.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.308-316
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• 2018

Background: Genus Sasa, dwarf bamboos, are considered to be species that lower biodiversity in the temperate forests of East Asia. Although they have a long interval, they, the monocarpic species, have a unique characteristic of large-scale synchronized flowering. Therefore, once they have flowered and then declined, it may be an opportunity for suppressed surrounding species. A previous study reported that Sasa borealis showed specialized flowering nationwide with a peak in 2015. However, this was based on data from a social network service and field survey at Mt. Jeombong. Therefore, we investigated S. borealis in the forests of five national parks in order to determine whether this rare synchronized flowering occurred nationwide, as well as its spatial distribution. Results: We found a total of 436 patches under the closed canopy of Quercus mongolica-dominated deciduous forests in the surveyed transects from the five national parks. Of these patches, 75% occupied a whole slope area, resulting in an enormous area. The patch area tended to be larger in the southern parks. Half (219 patches) of the patches flowered massively. Among them, 76% bloomed in 2015, which was consistent with the results of the previous report. The flowering rate varied from park to park with that of Mt. Seorak being the highest. The culms of the flowering patches were significantly taller (F = 93.640, p < 0.000) and thicker (F = 61.172, p < 0.000). Following the event, the culms of the flowering patches declined, providing a good opportunity for the suppressed plant species. The concurrent massive flowering of the mature patches was believed to be triggered by some stress such as a spring drought. Conclusion: We confirmed that the rare synchronized flowering of S. borealis occurred with a peak in 2015 nationwide. In addition, we explored that S. borealis not only monopolized an enormous area, but also dominated the floors of the late-successional Q. mongolica-dominated deciduous forests. This presents a major problem for Korean forests. As it declined simultaneously after flowering, there are both possibilities of forest regeneration or resettlement of S. borealis by massively produced seeds.

• Proceedings of the Plant Resources Society of Korea Conference
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.55-55
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• 2019

Strawberry which is the genus Fragaria under family Rosaceae is one of the most important fruit plants for both fresh consumption and food processing in the temperate and subtropical countries. Propagation of strawberry is achieved either through runners or by in vitro micropropagation. Meristem tips, generally obtained from runners of virus-free plants, are commonly used to establish in vitro cultures, which are employed for mass propagation or as a source of plant material for regeneration and transformation experiments. This study was conducted to determine the optimal natural additives strength to improve sprouting shoot rate of apical meristem of strawberry 'Seolhyang'. Strawberry apical meristem at size (0.2 mm to 0.3 mm) with leaf primordials were cultured on the 1/3MS(Murashige & Skoog) medium supplemented with five natural additives such as coconut milk, maple sap, banana powder and peptone. The sprouting ratio and growth characteristics were evaluated after eight weeks after in vitro culture. Shoot ratio of 'Seolhyang' apical meristem was 72.9% in 1/3MS medium supplemented with maple sap. On the other hand, the low shoot ratio was observed 47.7% in 1/3MS medium supplemented with banana powder. Shoot length was different as natural additives but numbers of leaf was not significantiy different among the natural additives. As a result, the sprouting ratio and plant growth were enhanced effectively in 1/3MS medium with maple sap compared to the others.

• Journal of Periodontal and Implant Science
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• 제49권3호
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• pp.148-157
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• 2019

Purpose: This study aimed to evaluate periodontal and pulpal healing in replanted rat teeth, preserved under different storage conditions, with or without root conditioning using doxycycline. Methods: A total of 40 maxillary first molars extracted from 20 Sprague-Dawley rats were stored for different durations under different conditions (5 minutes in dry storage and 60 minutes in Hank's balanced salt solution [HBSS]) and subsequently replanted. The rats were divided into 2 groups based on the use of root surface treatment: the doxycycline group (root surface treated with doxycycline) and the control group (no doxycycline treatment). Eight weeks after replantation, the animals were sacrificed, and the teeth were evaluated using micro-computed tomography (micro-CT) and histomorphometric analysis. Results: In the micro-CT analysis, the doxycycline group showed the same rate of occurrence of periapical radiolucency as was observed in the control group, but a lower degree of root resorption in teeth replanted after 60 minutes of storage in HBSS (P<0.05). In the histomorphometric analysis, the doxycycline group exhibited no improvement in either pulpal or periodontal healing of the replanted tooth after 5 minutes of dry storage, but showed a lower grade of surface root resorption ($1.37{\pm}0.77$) and inflammatory resorption in the teeth stored for 60 minutes in HBSS ($1.33{\pm}0.71$). Conclusions: In conclusion, doxycycline improved the periodontal healing of replanted teeth stored for 60 minutes in HBSS, whereas doxycycline did not improve periodontal healing of replanted tooth after 5 minutes of dry storage. Within the limits of this study, doxycycline showed more favorable periodontal healing despite delayed replantation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.16-16
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• 2019

The Cassava (Manihot esculenta Crantz) is a perennial woody shrub cultivated mainly in the tropics for its starchy tuberous roots. It belongs to the family Euphorbiaceae which also includes rubber (Hevea brasiliensis) and castor bean (Ricinus communis). Among tropical crops, rice, sugarcane, maize and cassava are the most important sources of calories for human consumption. Problems in the propagation of cassava are virus diseases and low rates of seed germination. Thus, a study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with single node after sterilization, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, single-node stem segments, approximately 1 cm in length, were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate was 55.6%, the shoot number and its length were 1.0/explant and 2.3 cm in the most favorable medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Journal of Korean Dental Hygiene Science
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• 제3권2호
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• pp.51-58
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• 2020

Oral examination ensures early detection and treatment of oral diseases and improvement of quality of health-related life. This is imperative as it reduces individuals' dental medical expenses and social costs caused by diseases. However, as the low oral examination acceptance rate continues to be a problem, this study was conducted to identify the factors that influence the oral examination of an economically active population. In this study, 4,836 economically active individuals between the ages of 20 and 65 years were studied using data from the 7th National Health and Nutrition Survey in 2018. Logistic regression analysis was performed to determine the factors influencing demographic and sociological characteristics on oral examination after adjusting for complaints of mastication and speech discomfort. As a result of confirming the factors influencing the oral examination, increase in age tended to be inversely proportional to the oral examination. Income level, type of job, and job position were identified as factors that influenced oral examinations. Compared to the group with a high socioeconomic status, which is represented by a group with a high income level or a stable job type or job position, the group with low economic status was found to have a negative effect on oral examination. Oral management of vulnerable groups, who might not be considered while devising oral health management policies, should be promoted through the development and provision of oral health management policies that consider employment status and environment.

• Journal of Plant Biotechnology
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• 제48권2호
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• pp.86-92
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• 2021

The present study aimed to evaluate the initiation, proliferation potential, and mass clonal production ability of a micropropagation system for banana through tissue culture. A total of 60 explants were cultured on basal media supplemented with various concentrations of BAP and NAA. Banana plants regenerated on MS basal medium (control) without the addition of BAP + NAA showed a significantly (P < 0.05) lower survival rate with no signs of shoots up to the end of the experimental period. The results further revealed that the performance in MSS-XI medium was almost 89%, followed by MSS-IX and MSS-X media, both of which showed performance up to 88%. In contrast, the performance in the MSS-XVI medium was less than 60%, at the less duration of time and highly shoot induction detected at MSS-XIII medium. The maximum number of shoots (4.9) was observed in the medium supplemented with growth adjuster MSS-XI, followed by the MSS-XII medium (4.5). Surprisingly, the best performance was observed for the MSR-VII medium approximately 16 days after initiation, while the lowest performance was observed with MSR-XI (approximately 31 days). The maximum rooting percentage (98%) was observed in the MSR-V to MSR-VIII media (98%), while the minimum rooting percentage was observed in MSR-XI (approximately 45%).

• Journal of the Korean Recycled Construction Resources Institute
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• 제9권2호
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• pp.117-126
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• 2021

An experimental study was carried out to investigate the applicability of cement-based materials for green soil which is a soil for promoting plant growth. The results show that the shear strength of the green soil mixed with gypsum cement (No.3) was low, but the hardness (23.6mm) and pH value (7.4) was most suitable for the vegetation environment. In addition, the initial vegetation germination of green soil, which improved performance by adding a moisturizer, was slower than that of general green soil, and the conductivity value tended to be slightly higher. On the other hand, the slope adhesion of advanced green soil was high, and it was found that the plant growth rate and the regeneration capacity were superior after time passed.