• 한국정보통신학회논문지
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• 제11권1호
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• pp.46-55
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• 2007

다음은 부동소수점 역수 및 역제곱근 계산에 많이 사용하는 뉴톤-랍손 알고리즘은 일정한 횟수의 곱셈을 반복하여 계산한다. 본 논문에서는 뉴톤-랍손 알고리즘의 반복 과정의 오차를 예측하여 오차가 정해진 값보다 작아지는 시점까지 반복 연산하는 개선된 뉴톤-랍손 알고리즘을 제안한다. 본 논문에서 제안한 알고리즘은 입력 값에 따라서 곱셈 횟수가 다르므로, 평균 곱셈 횟수를 계산하는 방식을 유도하고, 여러 크기의 근사 테이블에서 단정도실수 및 배정도실수의 역수 및 역제곱근 계산에 필요한 평균 곱셈 횟수를 산출한다. 이들 평균 곱셈 횟수를 종래 알고리즘과 비교하여 본 논문에서 제안한 알고리즘의 우수성을 증명한다. 본 논문에서 제안한 알고리즘은 오차가 일정한 값보다 작아질 때까지만 반복 연산을 수행하므로 역수 및 역제곱근 계산기의 성능을 높일 수 있고 최적의 근사 테이블을 구성할 수 있다. 본 논문의 연구 결과는 디지털 신호처리, 컴퓨터 그라픽스, 멀티미디어, 과학 기술 연산 등 부동소수점 계산기가 사용되는 분야에서 폭 넓게 사용될 수 있다.

• Journal of Korean Dental Science
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• 제13권2호
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• pp.52-58
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• 2020

Purpose: Using two types of electronic apex locators, this study aimed to investigate the differences in accuracy according to the evaluator and equipment. Materials and Methods: Artificial teeth of the lower first premolars and two mandibular acrylic models (A and B) were used in this study. In the artificial teeth, the pulp chamber was opened and the access cavity was prepared. Using calibrated digital Vernier calipers, the distance from the top of the cavity and the root apex was measured to assess the actual distance between two artificial teeth. The evaluation was conducted by 20 dentists, and each evaluator repeated measurements for each electronic apex locator five times. The difference between the actual distance from the top of the cavity to the root apex and the distance measured using electronic measuring equipment was compared. For statistical analysis, the Friedman test the Mann-Whitney U-test were conducted and the differences between groups were analyzed (α=0.05). Result: As for the accuracy of measurement according to the two types of electronic apex locators, the value of the measurement error was 0.4753 mm in Dentaport ZX and 0.3321 mm in E-Cube Plus. Moreover, electronic apex locators Dentaport ZX and E-Cube Plus showed statistically significant differences (P<0.05). As for the difference in the accuracy of the two types of electronic apex locators according to the evaluator, the resulting values differed depending on the evaluator and showed a statistically significant difference (P<0.001). Conclusion: Electronic apex locator E-Cube Plus showed higher accuracy than did Dentaport ZX. Nevertheless, both types of electronic apex locators showed 100% accuracy in finding the region within root apex ±0.5 mm zone. Furthermore, according to the evaluator, the two electronic apex locators showed different resulting values.

• Toxicological Research
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• 제31권1호
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• pp.77-88
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• 2015

Lithospermum erythrorhizon has long been used in traditional Asian medicine for the treatment of diseases, including skin cancer. The oral toxicity of a hexane extract of Lithospermum erythrorhizon root (LEH) was investigated in Beagle dogs by using single escalating doses, two-week dose range-finding, and 4-week oral repeat dosing. In the single dose-escalating oral toxicity study, no animal died, showed adverse clinical signs, or changes in body weight gain at LEH doses of up to 2,000 mg/kg. In a 2 week dose range-finding study, no treatment-related adverse effects were detected by urinalysis, hematology, blood biochemistry, organ weights, or gross and histopathological examinations at doses of up to 500 mg LEH/kg/day. In the 4 week repeat-dose toxicity study, a weight loss or decreased weight gain was observed at 300 mg/kg/day. Although levels of serum triglyceride and total bilirubin were increased in a dose dependent manner, there were no related morphological changes. Based on these findings, the sub-acute no observable adverse effect level for 4-week oral administration of LEH in Beagles was 100 mg/kg/day.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.31-31
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• 2018

Benign prostatic hyperplasia (BPH), which is the most common disorder in elderly men, involves androgenic hormone imbalance with chronic inflammation that causes imbalance between cell apoptosis and cell proliferation. As the root cause of the BPH remains unclear and synthetic drugs for treatment of BPH have undesirable side effects, the development of effective alternative medicines has been considered. Chinese Skullcap has been considered natural remedy to treat pyrexia, micturition disorder and inflammation. Although skullcap has effective properties on various diseases, the effects and molecular mechanism of Skullcap on BPH are not fully understood. Therefore, in this study, we evaluated the efficacy of Chinese Skullcap root extract (SRE) in testosterone-induced BPH rats. Compared with the untreated group, the SRE treatment group suppressed pathological alterations, such as prostate growth and increase in serum dihydrotestosterone and $5{\alpha}$-reductase levels. Furthermore, SRE significantly decreased the expression of androgen receptor and proliferating cell nuclear antigen. SRE also restored Bax/Bcl-2 balance. These effect of SRE was more prevalent than commercial $5{\alpha}$-reductase inhibitor, finasteride. Taken together, we propose that SRE suppresses abnormal androgen events in prostate tissue and inhibits the development of BPH by targeting inflammation- and apoptosis-related markers. These finding strengthens that SRE could be used as plant-based $5{\alpha}$-reductase inhibitory alternative.

• 대한소아치과학회지
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• 제6권1호
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• pp.43-52
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• 1979

The purpose of this study was to finding out the relationship between the tooth calcification and eruption of the mandibular permanent teeth in Korean. This study was undertaken in 592 children at ages from 3 to 13 years who had good oral condition by means of panoramic roentgenographic analysis. The following results were obtained. 1. The mean ages of crown completion were as follows; Canine 1st. Premolar 2nd. Premolar 1st. Molar Male 6yrs. 4mos. 6yrs. 8mos. 7yrs. 6mos. 7yrs. 6mos. Female 5yrs. 11mos. 6yrs. 5mos. 7yrs. 2mos. 3yrs. 3mos. 2. Each tooth started to move toward occlusion at approximately stage 6 or after crown completion. 3. The highest increment in eruption rate was at about 1/3~1/2 completion of root and ages at 10-11 years in male, 9-10 years in female. 4. Eruption period of both sexes were as follows; Canine: 6-12years 1st. Premolar: 7-12 years 2nd. Premolar: 7-13 years 1st. Molar: 3-7 years 5. The eruption was completed before the root completion. 6. The sequence of eruption and calcification was 1st. Molar-Canine-1st. Premolar-2nd. Premolar in both sexes.

• 한국한의학연구원논문집
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• 제16권1호
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• pp.141-147
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• 2010

Objectives : The aim of present study is to examine the effect of methanolic extract from the root of Bupleurum falcatum L. (BF) on acute cocaine-induced c-Fos expression in the rat caudate putamen (CPu), a major dopaminergic terminal. Methods : Male Sprague-Dawley rats were subjected to an intraperitoneal injection with either cocaine hydrochloride (20 mg/kg) or saline 30 min after an administration of either extract of BF (100 mg/kg, i.p.) or vehicle. Animals were sacrificed 2 hr after treatment with cocaine or saline for immunohistochemistry. Quantification of brain slices was examined for c-Fos positive nuclei using light microscopy. Results : Pretreatment with BF significantly attenuated cocaine-induced c-Fos expression in the rat CPu. Conclusions : This finding suggests that BF has the inhibitory effect on cocaine-induced c-Fos expression in the rat CPu via possibly modulating the activities of central dopaminergic systems.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.23-36
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• 2021

The study explores the nexus between foreign direct investment (FDI), financial innovation, and exchange rate volatility in selected South Asian countries for 1980 to 2017. The study applies the unit root test, Autoregressive Distributed Lagged, nonlinear ARDL, and causality test following Toda-Yamamoto. Unit root tests ascertain that variables are integrated in a mixed order; few variables are stationary at a level and few after the first difference. Empirical model estimation with ARDL, Long-run cointegration revealed with the tests of FPSS, WPSS, and tBDM by rejecting the null hypothesis of "no cointegration." This finding suggests that, in the long-run financial innovation, FDI inflows, and exchange rate volatility move together. Moreover, study findings established adverse effects running from FDI inflows and financial innovation to exchange rate volatility in the long run. These findings suggest that continual FDI inflows and innovativeness in the financial system assist in lessening the volatility in the foreign exchange market. Furthermore, nonlinear ARDL confirms the presence of asymmetric cointegration in the model. The standard Wald test established asymmetric effects running from FDI inflows and financial innovation to exchange rate volatility, both in the long and short run. Directional causality unveils feedback hypothesis holds for explaining causality between FDI, financial innovation, and exchange rate volatility.

• Journal of Forest and Environmental Science
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• 제26권3호
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• pp.171-179
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• 2010

Effect of chromium (Cr) stress on antioxidant enzyme activities and malondialdehyde (MDA) content were investigated in leaves and roots of mangrove (italic (L.) Druce) seedlings. Cr toxicity effects were also assessed on young seedlings. The seedlings were grown in green house condition for three months in nutrient solution with 0, 0.5, 1, 1.5, 2, 2.5, and 3 mg $L^{-1}$ $CrCl_3$. This study showed that Cr led to the change of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and activities at different concentrations. The activity of antioxidant enzymes in leaves of K. candel seedlings indicates that enzymes engaged in antioxidant defense in certain level especially in low concentration of Cr treatments. The activities of SOD and POD were activated by Cr in the root level, while CAT activity was inhibited. CAT activity decreased in response to high concentrations of Cr. In the present study indicated that SOD in root was active in scavenging the superoxide produced by Cr. Both in roots and leaves, an increase in malondialdehyde (MDA) content was observed with increase in metal concentration and exposure periods. Our finding indicated that the high concentration of excessive Cr supply may interfere with several metabolic processes of seedlings, causing toxicity to plants as exhibited by chlorosis, necrosis, photosynthetic impairing and finally, plant death.

• Journal of Periodontal and Implant Science
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• 제29권4호
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• pp.893-914
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• 1999

Tooth mobility may be the decisive factor that determines whether dental treatment of any kind is undertaken. Although tooth mobility in isolation says little in itself, the finding of increased tooth mobility is of both diagnostic and prognostic importance. Only the detection of an increase or decrease in mobility makes an evaluation possible. Thus prior to treatment, we must understand the pathologic process causing the observed the tooth mobility and decide whether the pattern and degree of observed tooth mobility is reversible or irreversible. And then it must be decided whether retention and treatment or extraction and replacement. The purpose of this study was to compare tooth mobility at different time period during root planing and flap operation and to relate changes in mobility to each treatment method. Twenty-one patients (287 teeth) with chronic adult periodontitis were treated with root planing(control group) and flap operation(experimental group), and each group was divided 3 subgroups based upon initial probing pocket depth (1-3mm, 4-6mm, 7mm and more). Tooth mobility was measured with $Periotest^{(R)}$ at the day of operation, 4 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 8 weeks, 12 weeks after each treatment. Tooth mobility, attachment loss, radiographic bone loss, and bleeding on probing were measured at the day of operation, 4 weeks, 8 weeks and 12 weeks after treatment. 1. In group initial probing depth was 1-3mm, tooth mobility had no significant difference after root planing and flap operation. 2 . In group initial probing depth was 4-6mm, 7mm and more, tooth mobility had decreased in 12 weeks after root planing(p<0.01). And the mobility had increased after flap operation(p<0.01) and was at peak in 1 week, and decreased at initial level in 4 weeks, below the initial level in 12 weeks(p<0.01). 3. In 1 week, significant difference in tooth mobility between control and experimental group was found(p<0.01) but, in 12 weeks no difference between two groups was found. 4. Change of immediate tooth mobility after treatment was more larger in deep pocket than in shallow one. In group with the same probing pocket depth, the change of tooth mobility in molar group was greater than that of premolar group. 5. Tooth mobility before treatment was more strongly correlated with radiographic bone loss (r=0.5325) than probing depth, attachment loss and bleeding on probing, in 12 weeks after treatment, was more strongly correlated with attachment loss($r^2$=0.4761) than probing depth and bleeding on probing. Evaluation of the treatment effect and the prognosis after root planing and flap operation were meaningful on tooth initial probing depth 4mm and more. After flap operation, evaluation of the prognosis should be performed at least in 4 weeks and in 12 weeks after treatment, no difference in tooth mobility between two groups was observed. Radiographic bone loss and attachment loss were good clinical indicators to evaluate tooth mobility.

• Journal of Ginseng Research
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• 제27권2호
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• pp.78-85
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• 2003

Agrobacterium rhizognes $A_4$ Ti-plasmid를 인삼 뿌리에 도입하여 유전적으로 안정하며 반영구적으로 이용할 수 있는 형질전환된 인삼모상근 캘러스(GHC-T78)를 유도하였다. 특정 ginsenoside를 대량으로 생산할 수 있는 최적배양조건을 확립하기 위해서 먼저 모상근으로부터 캘러스의 유도하는 과정에서 BA의 단독 처리구는 auxin과 cytokinin의 혼합 처리구보다 캘러스 형성이 더 우수하였다. 인삼 캘러스 형성율은 Benzyladenine(BA)를 1 mg-3 mg/L 까지 첨가한 배지에서 가장 높게 나타났으며, ginsenoside 함량 역시 bezyladenine 단독처리구는 가장 우수하였다. 캘러스 세포의 액체배양 기간을 4주로 설정할 때 BA의 농도 역시 BA 2 mg/L로 첨가한 배지에서 가장 우수한 캘러스 생장률을 보였다. 실제로 인삼 모상근 캘러스의 생장율은 암상태에서 배양하는 것이 광상태에서 보다 다소 양호하였으나, ginsenoside의 생성에는 연속광상태에서 더 효과적임이 확인되었다. 모상근 캘러스에서 얻은 이러한 결과는 국내외 처음으로 보고되는 내용이며, 액체배양의 캘러스 세포에서 분화된 무수히 많은 단일 모상근 근모의 형성은 액체배양을 통한 특정 ginsenosid의 새로운 생산방법을 개발할 수 있도록 하고 있다.