• 식물조직배양학회지
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• 제24권3호
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• pp.167-173
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• 1997

The embryogenic callus (EC), from which somatic embryos could be induced, was compared with nonembryogenic callus(NE) to study the origin and features of totipotent cell in water dropwort (Oenanthe stolonifera DC). To induce and maintain of EC and the NE, meristematic stem and immature floret were inoculated in MS media supplemented with 1 mg/L 2,4-D, and with 2.5 mg/L NAA and 5mg/L BA, respectively, The EC was not induced from the NE even after subculturing in MS medium supplemented with 1 mg/L 2,4-D. Plantlets were not regenerated from the NE in hormone-free medium. In histochemical comparison of the EC with the NE by light microscopy, the EC had smaller cells in size, dense cytoplasm, and more starch granules of cells compared to the NE cells. The cell from the EC, as observed by transmission electron microscopy, had smaller vaculoes, well developed ribosomes, mitochondria, and endoplasmic reticulum, whereas the cells from the NE had larger vacuoles and underdeveloped organelles. In protein pattern from NE, EC and Somatic embryo (SE), as analyzed by SDS polyacrylamide gel electrophoresis, different proteins specific for tissue were observed: 17 and 28 KD for NE, 50, 52, 57, 66, 68 KD for EC and 20 KD for SE. DNA polymorphism was also observed between EC and NE as analyzed by RAPD (randomly amplified polymorphic DNA) method. The origin of totipotent stem cell and the relationship between irreversible genomic change arose in differentiation and the loss of totipotency in plant were discussed.

• 한국응용과학기술학회지
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• 제13권1호
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• pp.99-105
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• 1996

Furfurylidene acetophenone derivatives were synthesis, it was measured that hydrolysis made use of UV at a wide pH $1.0{\sim}13.0$ range in 30% $dioxane-H_2O$ solution, $25{\pm}1^{\circ}C$. On the basis of general base catalysis, substitutent effect, confirmation of hydrolysis products, it was measured the reaction rate of furfurylidene acetophenone derivatives for the pH change. It maybe concluded that a part was unrelated to pH and another part was in proportion to concentration of hydroxide ion : Above pH 10.0, It was in proportion to concentration of hydroxide ion, a part having no concern with pH was added to the neutral $H_2O$ molecule. From the result of measurement the reaction rate, hydrolysis of furfurylidene acetophenone derivatives confirmed to the irreversible first order. Through measurement the substituent effect, It found that reaction rate was accelerated by electron attracting group. Also, From the result of final product, There were furfural and acetophenone. On the basis of these findings, Hydrolysis for the furfurylidene acetophenone derivative was proposed a fitting mechanisms.

• Ocean and Polar Research
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• 제43권2호
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• pp.53-63
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• 2021

Changes in a marine environment have a broad socioeconomic implication on fisheries and their relevant industries so that there has been a growing demand for the medium-range (months to years) prediction of the marine environment Using a medium-range ocean prediction model (Ocean Mid-range prediction System, OMIDAS) for the northwest Pacific, this study attempted to assess seasonal difference in the mid-range predictability of the sea surface temperature (SST), focusing on the Korea seas characterized as a complex marine system. A three-month re-forecast experiment was conducted for each of the four seasons in 2016 starting from January, forced with Climate Forecast System version 2 (CFSv2) forecast data. The assessment using relative root-mean-square-error was taken for the last month SST of each experiment. Compared to the CFSv2, the OMIDAS revealed a better prediction skill for the Korea seas SST, particularly in the Yellow sea mainly due to a more realistic representation of the topography and current systems. Seasonally, the OMIDAS showed better predictability in the warm seasons (spring and summer) than in the cold seasons (fall and winter), suggesting seasonal dependency in predictability of the Korea seas. In addition, the mid-range predictability for the Korea seas significantly varies depending on regions: the predictability was higher in the East Sea than in the Yellow Sea. The improvement in the seasonal predictability for the Korea seas by OMIDAS highlights the importance of a regional ocean modeling system for a medium-range marine prediction.

• 대한화학회지
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• 제66권2호
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• pp.92-95
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• 2022

Failure Renal is the function of the kidneys to remove waste products and keep them on the periphery. and minerals for the body. Chronic renal failure is a syndrome characterized by a slow, irreversible deterioration of renal function due to the slow destruction of renal parenchyma. Calcium is one of the important minerals that the body contains in the blood and important tissues, and it has an important role in vital processes such as muscle contraction, nerve impulse conduction, the efficiency of heart muscle work, and blood clotting processes. The aim of the study is to study and compare calcium levels in men and women. It includes studying abnormal levels of calcium that cause many diseases, including chronic renal failure, and studying changes associated with renal failure. The method of this study was conducted on patients with chronic renal failure at Murjan Teaching Hospital in Babylon city during the period. The study included a sample of 70 patients (40 males, 30 females) with chronic renal failure, their ages ranged from 30-65, and 60 (30 males, 30 females) healthy without the disease of the same age. The result was a significant decrease in the number of red and white blood cells, hemoglobin concentration, hematocrit and platelets in patients with chronic renal failure, The result has been showed significant level in enzymes activity for transfer of amine group (alanine amino transferase, aspartate amino transferas) and phosphatase alkaline and also concentration of total bilirubin in patient with compare with healthy, Significantly increases, were found in the concentration of urea, uric acid and creatinine, as well as the concentration of calcium and phosphorous ions in the blood serum of patients compared to healthy controls.

• 한국표면공학회지
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• 제56권1호
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• pp.104-114
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• 2023

Three dimensional (3D) porous structures consisting of Cu@CoO core-shell-type nano-dendrites were synthesized and tested as the anode materials in lithium secondary batteries. For this purpose, first, the 3D porous films comprising Cu@Co core-shell-type nano-dendrites with various thicknesses were fabricated through the electrochemical co-deposition of Cu and Co. Then the Co shells were selectively anodized to form Co hydroxides, which was finally dehydrated to get Cu@CoO nanodendrites. The resulting electrodes exhibited very high reversible specific capacity almost 1.4~2.4 times the theoretical capacity of commercial graphite, and excellent capacity retention (~90%@50^th cycle) as compared with those of the existing transition metal oxides. From the analysis of the cumulative irreversible capacity and morphology change during charge/discharge cycling, it proved that the excellent capacity retention was attributed to the unique structural feature of our core-shell structure where only the thin CoO shell participates in the lithium storage. In addition, our electrodes showed a superb rate performance (70.5%@10.8 C-rate), most likely due to the open porous structure of 3D films, large surface area thanks to the dendritic structure, and fast electron transport through Cu core network.

• 한국표면공학회지
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• 제56권1호
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• pp.62-68
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• 2023

Silicon (Si) is considered as a promising substitute for the conventional graphite due to its high theoretical specific capacity (3579 mAh/g, Li₁₅Si₄) and proper working voltage (~0.3V vs Li⁺/Li). However, the large volume change of Si during (de)lithiation brings about severe degradation of battery performances, rendering it difficult to be applied in the practical battery directly. As a one feasible candidate of industrial Si anode, silicon monoxide (SiO_x) demonstrates great electrochemical stability with its specialized strategy, downsized Si nanocrystallites surrounded by Li⁺ inactive buffer phase (Li₂O and Li₄SiO₄). Nevertheless, SiO_x inherently has the initial irreversible capacity and poor electrical conductivity. To overcome those issues, conformal carbon coating has been performed on SiO_x utilizing ethylbenzene as the carbon precursor of chemical vapor deposition (CVD). Through various characterizations, it is confirmed that the carbon is homogeneously coated on the surface of SiO_x. Accordingly, the carbon-coated SiOx from CVD using ethylbenzene demonstrates 73% of the first cycle efficiency and great cycle life (88.1% capacity retention at 50th cycle). This work provides a promising synthetic route of the uniform and scalable carbon coating on Si anode for high-energy density.

• 한국재료학회지
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• 제33권6호
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• pp.257-264
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• 2023

To develop a high capacity lithium secondary battery, a new approach to anode material synthesis is required, capable of producing an anode that exceeds the energy density limit of a carbon-based anode. This research synthesized carbon nano silicon composites as an anode material for a secondary battery using the RF thermal plasma method, which is an ecofriendly dry synthesis method. Prior to material synthesis, a silicon raw material was mixed at 10, 20, 30, 40, and 50 wt% based on the carbon raw material in a powder form, and the temperature change inside the reaction field depending on the applied plasma power was calculated. Information about the materials in the synthesized carbon nano silicon composites were confirmed through XRD analysis, showing carbon (86.7~52.6 %), silicon (7.2~36.2 %), and silicon carbide (6.1~11.2 %). Through FE-SEM analysis, it was confirmed that the silicon bonded to carbon was distributed at sizes of 100 nm or less. The bonding shape of the silicon nano particles bonded to carbon was observed through TEM analysis. The initial electrochemical charging/discharging test for the 40 wt% silicon mixture showed excellent electrical characteristics of 1,517 mAh/g (91.9 %) and an irreversible capacity of 133 mAh/g (8.1 %).

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.173-182
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• 1996

This study was performed to provide the information on the clinical characteristics of the most common paroxysmal pain disorder in maxillofacial region, trigeminal neuralgia, and the effects and side effects of carbamazepine. The patients who visited Orofacial Pain Clinic, Dept. of Oral Diagnosis, Seoul National University Dental Hospital for treating paroxysmal pain were studied by history taking, clinical examination, and radiography. Sixty-two patients(male 20, female42) without any clinical and radiological abnormalities were Included. The change of pain, blood tests, and side effects were investigated periodically after administration of carbamazepine. The obtained results were as follows : 1. Almost all patient with trigeminal neuralgia were over the age of forties and it was more common in women. 2. Trigeminal neuralgia was more right sided and the involved nerve was in the order of maxillary n., mandibular n., and ophthalmic n. 3. The mean duration of suffering was 20.7 months. Eighty percent of patients had apparent trigger area. 4. The duration of pain attack was in the older of several seconds, 1 min. to 5 min., more than 10 min., and 5 min. to 10 min. The frequency of pain attack was in the order of more than 10 per day, 6-10 per day, and 1-5 per day. 5. The clinic the patients had visited for reducing neuralgic pain was in the order of dental clinic, neurology, oriental medicine, otolaryngology, and pharmacy. 6. Unnecessary dental treatments for reducing neuralgic pain were performed in 41.9% of the patients. Almosit all treatments were irreversible ones such as endodontic treatment and tooth extraction. 7. The initial mean VAS was 8.6, but it was decreased to 3.8 after 1 month, to 2.7 after 2 months. Almost all patients showed decreased pain with 200-600mg/day of carbamazepine to 6 months. 8. WBC counts, especially neutrophil counts, was decreased in 1 week after administration of carbamazepine but reached initial level after 1 month. SGOT, SGPT, and creatinine did not show any significant change. 9. Blood pressure was not changed significantly after administration of carbamazepine. 10. Almost patients did not show any apparent side effects, but drowsiness, dizziness, skin itching, constipation, and gastric irritation were occurred in some patients.

• 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.

• 한국해양환경ㆍ에너지학회지
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• 제10권4호
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• pp.201-210
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• 2007

생태계로 유입되는 POPs, EDCs, PBTs 등과 같은 화학물질에 의한 오염은 점점 복잡다양화 되고 있으며, 사람의 건강이나 생태계에 돌이킬 수 없는 피해를 가져올 우려 또한 증가되고 있다. 그러나 위해성 평가의 중요한 과정중 하나인 화학물질의 노출량 산정 부분에 대한 적정한 평가가 이루어지지 않는 경우가 많았다. 본 연구에서는 환경매체 중 화학물질량 산정에 있어 보다 효율적인 모델링 수행을 위하여, 화학물질의 물성 데이터베이스 및 지역 개황 데이터베이스 등과 프로그램으로 연계되어 있으며, 동시에 여러 대상물질이 시뮬레이션 가능한 다매체환경모델 MUSEM(Multi-media Simple box-systems Environmental Model)을 이용하여 62종의 화학물질에 대하여 일본 47개 지역의 환경매체 중 농도예측 및 동경지역에 대한 민감도 분석을 통하여 모델의 적용성을 검토하였다. 이러한 62종의 물질에 대한 매체별 잔류비(%)는 수역에 고비율로 분포하는 물질이 많은 것으로 예측되었다. 옥탄올-물 분배계수에 따른 환경매체중의 화학물질 농도변화는 도시산업용지의 토양 및 담수의 저질에서 상대적으로 크게 나타났으며, 대기와 담수에서는 상대적으로 작게 나타났다. 분해계수에 의한 환경매체중의 화학물질 농도변화는 육수역 물환경 및 도시산업용지의 토양, 육수역의 저질에서의 변화폭이 비슷하게 나타났으며 대기의 경우는 상대적으로 작게 나타났다.