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Morphometric Study of the Irradiation Effect on the Cartilage Formation in the Rat Mandibular Condyle (방사선 조사가 백서 하악과두 연골 형성에 미치는 영향에 관한 형태계측학적 연구)

  • Kim Jeong-Hwa;Heo Min-Suk;Lee Sam-Sun;Choi Soon-Chul
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.29 no.1
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    • pp.87-103
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    • 1999
  • Purpose: This study was undertaken to quantitatively estimate the degree of the damage and recovery of the irradiated rat condylar cartilage using the Image Analyzer. Materials and Methods: Experimental animals were 16 male rats of the Sprague-Dawley strain at the age of 20 day irradiated with the dose of 10 Gy in their head and neck region. Four rats were sacrificed at the each of the following time intervals - 1, 4, 7 and 14 days, respectively. The same number of control group animals were sacrificed at the each age of 21. 24, 27 and 34 days, respectively. The specimens were stained with 0.5% toluidine blue and examined with light microscope. The condylar cartilage was divided into 4 zones; fibrous zone, proliferating zone, upper hypertrophic zone, and lower hypertrophic zone. And then, the proliferating zone was subdivided into 2 layers - upper and lower layer, and upper and lower hypertrophic zone were subdivided into three layers, respectively - upper, middle and lower layer. With the aid of Image Analyzer, morphometric analysis was performed. The thickness, the numerical density of cells, the cell area density, the extracellular matrix area density, the mean area of single cell, the mean area of extracellular matrix per single cell were measured and analysed. Results: In the experimental group, the thickness of the fibrous zone was slightly increased and that of the proliferating zone and the upper and the lower hypertrophic zone was markedly decreased. With time, the thickness of the fibrous zone was gradually increased and that of the proliferating zone and the upper and the lower hypertrophic zone was steadily in the decreased state. The numerical density of cells of the proliferating zone was increased on post-irradiated 1 day, but decreased after post-irradiated 4 day, and that of the upper hypertrophic zone was decreased. The numerical density of cells of the lower hypertrophic zone was decreased in the early stage and then was decreased or not significantly different from that of the control group with time. In the experimental group, the cell area density of the fibrous zone and the proliferating zone was decreased in the early stage and then gradually increased or not significantly different from that of the control group with time. The cell area density of the upper and the lower hypertrophic zone was varied with time. The extracellular matrix area density value were totally opposite to the cell area density values: The mean area of single cell of the fibrous zone and the proliferating zone was .decreased on post-irradiated 1 day, and increased after post-irradiated 4 day. The mean area of single cell of the upper hypertrophic zone was varied with each layer and time. In the experimental group, the mean area of extracellular matrix per single cell of the fibrous zone was not significantly different with control group, and that of the proliferating zone was decreased on post-irradiated 1 day, and increased after post-irradiated 4 day. The mean area of extracellular matrix per single cell of the lower hypertrophic zone was increased in the early stage. and that of upper hypertrophic zone was varied with each layer and time. Conclusion: The condylar cartilages of rats were affected by irradiation, but the changes were vaned with each layer and time. By morphometric analysis. the changes of the cells of the condylar cartilage of irradiated rat could be calculated quantitatively.

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A STUDY ON THE CHILD PATIENT'S PREFERENCE TOWARD DENTIST'S ATTIRE (소아환자의 치과의사 복장에 대한 선호도 연구)

  • Wee, You-Min;Lee, Chang-Seop;Lee, Sang-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.2
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    • pp.168-179
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    • 2002
  • The purpose of this study was to find a method for improving the children's behavior during dental treatment in relation with dentist's attire. For this study 150 children, visiting a dental clinic, were asked to participate in a survey on the attire of the dentist. The results of the survey were as follows: 1. In the survey for the preference between gown and ordinary clothes according to sex(P<0.05), age(P<0.05), residence (P<0.05) and number of visits(P<0.05), there was more preference for gown(65.3%). 2. The preference for the type of gown and attire under the gown was a long gown and white shirt (30.7%), followed by a suit-like gown (18.7%) and white shirt, and long gown and polo shirt(17.3%). 3. The preference for the color of gown was white(34.7%), followed by pink (18.7%), green(18.0%), blue(15.3%) and yellow(13.3%). 4. The preference for the pattern on the gown was cartoon characters(49.3%), followed by hospital logo(28.7%) and no pattern(14.7%). 5. The preference for ordinary clothes of female dentists was polo shirt(37.3%), followed by striped shirt(28.7%), round T-shirt(18.7%), and everyday Korean traditional dress(15.3%). 6. The preference for ordinary clothes of male dentists was pattern necktie and no pattern Y-shirt(28.0%), followed by no pattern necktie and Y-shirt(21.3%) or pattern shirt with no necktie, and no pattern Y-shirt with no necktie(14.7%). 7. The preference on the protective equipment worn was mask and glove(28.7%), followed by no protective equipment(26.7%), mask, glove and protective glasses(22.7%) at)d only mask(22.0%). Based on the above results, it seems that parting with the traditional white gown and wearing multi-color and pattern attire will provide psychological stability and help improve children's behavior during treatment.

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Scientific Analysis of the Historical Characteristics and Painting Pigments of Gwaebultaeng in Boeun Beopjusa Temple (보은 법주사 <괘불탱>의 미술사적 특징과 채색 안료의 과학적 분석 연구)

  • Lee, Jang-jon;Gyeong, Yu-jin;Lee, Jong-su;Seo, Min-seok
    • Korean Journal of Heritage: History & Science
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    • v.52 no.4
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    • pp.226-245
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    • 2019
  • Beopjusa Gwaebultaeng (Large Buddhist Painting), designated as Treasure No. 1259, was painted in 1766 and featured Yeorae (Buddha) at the center in the style of a single figure. It is the longest existing buddhist painting and was created by Duhun, a painter who was representative of 18th century Korean artists. His other remaining work is Seokgayeorae Gwaebultaeng (1767) in Tongdosa Temple. Considering their same iconography, they are assumed to have used the same underdrawing. Duhun had a superb ability to maintain a consistent underdrawing, while most painters changed theirs within a year. The Beopjusa painting carries significance because it was not only painted earlier than the one in Tongdosa, but also indicates possible relevance to the royal family through its records. Beopjusa Temple is also the site of Seonhuigung Wondang, a shrine housing the spirit tablet of Lady Yi Youngbin, also known as Lady Seonhui. Having been built only a year before Beopjusa Gwaebultaeng was painted, it served as a basis for the presumption that it has a connection to the royal family. In particular, a group of unmarried women is noticeable in the record of Beopjusa painting. The names of some people, including Ms. Lee, born in the year of Gyengjin, are recorded on the Bonginsa Temple Building, the construction of which Lady Yi Youngbin and Princess Hwawan donated money to. In this regard, they are probably court ladies related to Lady Yi Youngbin. The connection of Beopjusa Gwaebultaeng with the royal family is also verified by a prayer at the bottom of the painting, reading "JusangJusamJeonhaSumanse (主上主三殿下壽萬歲, May the king live forever)." While looking into the historical characteristics of this art, this study took an approach based on scientific analysis. Damages to Beopjusa Gwaebultaeng include: bending, folding, wrinkles, stains due to moisture, pigment spalling, point-shaped pigment spalling, and pigment penetration to the lining paper at the back. According to the results of an analysis of the painting pigments, white lead was used as a white pigment, while an ink stick and indigo were used for black. For red, cinnabar and minium were used independently or were combined. For purple, organic pigments seem to have been used. For yellow, white lead and gamboge were mixed, or gamboge was painted over white lead, and gold foil was adopted for storage. As a green pigment, atacamite or a mixture of atacamite and malachite was used. Azurite and smalt were used separately or together as blue pigments.

MICROLEAKAGE AND SHEAR BOND STRENGTH OF FLOWABLE COMPOSITE RESIN (Flowable Composite Resin의 미세변연누출 및 전단결합강도)

  • 박성준;오명환;김오영;이광원;엄정문;권혁춘;손호현
    • Restorative Dentistry and Endodontics
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    • v.26 no.4
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    • pp.332-340
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    • 2001
  • Flowable composite resin has lower filler content, increased flow, and lower modules of elasticity. It is suggested that flowable composite resin can be bonded to the tooth structure intimately and absorb or dissipate the stress. Therefore, it may be advantageous to use flowable composite resin for the base material of class II restoration and for the class V restoraton. The purpose of this study was to evaluate the microleakage and shear bond strength of four flowable composite resins (Aeliteflo, Flow-It, Revolution, Ultraseal XT Plus) compared to Z100 using Scotchbond Multi Purpose dentin bonding system. To evaluate the microleakage, notch-shaped class V cavities were prepared on buccal and lingual surfaces of 80 extracted human premolars and molars on cementum margin. The teeth were randomly divided into non-thermocycling group (group 1) and thermocycling group (group 2) of 40 teeth each. The experimental teeth of each group were randomly divided onto five subgroups of eight samples (sixteen surfaces). The Scotchbond Multi-Purpose and composite resin were applied for each group following the manufacturer's instructions. the teeth of group 2 were thermocycled five hundred times between 5$^{\circ}C$ and 55$^{\circ}C$. The teeth of group 2 were placed in 2% methylene blue dye for 24 hours, then rinsed with tab water. The specimens were embedded in clear resin, and sectioned longitudinally with a diamond saw. The dye penetration on each of the specimen were observed with a stereomicioscope at $\times$20 magnification. To evaluate the shear bond strength, 60 teeth were divided into five groups of twelve teeth each. The experimental teeth were ground horizontally below the dentinoenamel junction, so that no enamel remained. After applying Scotchbond Multi-Purpose on the dentin surface, composite resin was applied in the shape of cylinder. The cylinder was 4mm in diameter and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. After shear bond strength measurement, mode of failure was evaluated with a stereomicroscope at $\times$30 magnification. All data were statistically analyzed by One Way ANOVA and Student-Newman-Keuls method. The correlation between microleakage and shear bond strength was analyzed by linear regression. The results of this study were as follows ; 1. In non-thermocycling group, the leakage value of Z100 was significantly lower than those of flowable composite resins at the enamel and dentin margin, margin, except that Revolution showed the lower leakage value than that of Z100 at the dentin margin (p<0.05). 2. In thermocycling group, the leakage values of Z100 and Ultraseal XT Plus were lower than those of other subgroup at the enamel and dentin margin, except that Flow-It showed the lower leakage value than that of Ultraseal XT Plus at the dentin margin (p<0.05). 3. The leakage value of Z100 and Ultraseal XT Plus in thermocycling group were not higher than that in non-thermocycling group at the enamel margin. The leakage value of Z100 in thermocycling group was not higher than that in non-thermocycling group at the dentin margin (p<0.05). 4. As for the shear bond strength measurement, there were no statistically significant differences among groups (p<0.05). The shear bond strengths given in descending order were as follows: Z100(16.81$\pm$2.98 MPa), Flow-It(14.8$\pm$4.43 MPa), Aeliteflo(14.34$\pm$3.69 MPa), Revolution(13.46$\pm$4.23 MPa), Ultraseal XT Plus(12.83$\pm$3.16 MPa). 5. Failure modes of all specimens were adhesive failures. 6. There was no correlation between microleakage and shear bond strength.

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Optimization of HPLC Method and Clean-up Process for Simultaneous and Systematic Analysis of Synthetic Color Additives in Foods (식품 중 타르색소의 동시분석 및 계통분석을 위한 HPLC 분석조건 및 정제과정 확립)

  • Park, Sung-Kwan;Hong, Yeun;Jung, Yong-Hyun;Lee, Chang-Hee;Yoon, Hae-Jung;Kim, So-Hee;Lee, Jong-Ok
    • Korean Journal of Food Science and Technology
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    • v.33 no.1
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    • pp.33-39
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    • 2001
  • To develop a method for separation process using Sep-pak $C_18$, simultaneous and systematic analysis of 8 permitted and 11 non-permitted synthetic food colors in Korea, optimization of analysis conditions for reverse phase ion-pair high performance liquid chromatography was carried out. For the best result of Sep-pak $C_18$ separation the pH of color standard mixture solution was $5{\sim}6$ and 0.1% HCl-methanol solution were set as eluent. The colors eluated from Sep-pak $C_18$ cartridge were determined and confirmed by high performance liquid chromatography with a photodiode array detector at 420 nm for yellow colors type, at 520 nm for red colors type, at 600 nm for blue and green colors type and at 254 nm for mixed colors. Conditions for HPLC analysis were as follows: column, Symmetry $C_18$ (5 m, 3.9 mm $i.d.{\times}150\;mm$); mobile phase, 0.025 M ammonium acetate (containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (65 : 25 : 10) and 0.025 M ammonium acetate(containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (40 : 50 : 10); flow rate, 1 mL/min. It takes 35 minutes for simultaneaus analysis and 18 minutes for systematic analysis. The detection limits range of each colors were $0.01{\sim}0.05\;{\mu}g/g$.

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Extraction and Characteristics of Purple Sweet Potato Pigment (자색고구마 색소의 추출과 특성)

  • Kim, Seon-Jae;Rhim, Jong-Whan;Lee, Lan-Sook;Lee, Joon-Seol
    • Korean Journal of Food Science and Technology
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    • v.28 no.2
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    • pp.345-351
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    • 1996
  • Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

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Characteristics of Cooked Rice by Adding Grains and Legumes (곡류와 두류를 혼합한 잡곡의 취반 특성)

  • 임상빈;강명수;좌미경;송대진;오영주
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.1
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    • pp.52-57
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    • 2003
  • Nutritional compositions of the raw materials, such as well-milled rice, milled upland glutinous rice, milled barley, glutinous millet, SoRiTae, red beans and mung beans were analysed, and cooking characteristics and sensory attributes of mixed cereals were measured. Crude protein and crude fat in SoRiTae were 31.6% and 16.16%, respectively, and the highest among the raw materials. Crude ash was 3~11 times higher and crude fiber was 5~7 times higher in legumes than in grains. Iron content in SoRiTae was the highest as 7.8 mg/100 g, and calcium content was the highest as 71.0 mg/100 g in SoRiTae and mung beans. Phosphorus content was higher in glutinous millet and mung beans, and potassium content was greatly higher in legumes than in grains and the highest as 934 mg/100 g in red beans. Vitamin B$_1$ and B$_2$ contents were higher in legumes than in grains, and niacin content was the highest as 5.51 mg/100 g in mung beans and was 3.77 mg/100 g in glutinous millet. Water uptake of the raw materials increased greatly after 5 min of soaking in water and then stayed at the almost same level. Water uptake was the highest in SoRiTae and decreased in the order of milled barley, milled upland glutinous rice, glutinous millet and well-milled rice. Hardness was the lowest as 142.8 g/cm$^2$ in cooked SoRiTae, and the highest as 206.3 g/cm$^2$ in cooked milled barley compared with 169.4 g/cm$^2$ in cooked well-milled rice. Cooking time increased and hardness of cooked mixed cereals decreased with the increase of water added. Moisture content decreased, while crude protein, crude ash and crude fiber increased as the increase of mixing ratio of SoRiTae and red beans in mixed cereals. Lightness decreased, while red and blue color increased, and hardness increased with the increase of mixing ratio of SoRiTae and red beans. Sensory evaluation showed greater preference in terms of color, roasted nutty, sweet taste and overall acceptance in the cooked mixed cereals with 8 and 10% of SoRiTae and red beans.

The study of stereoscopic editing process with applying depth information (깊이정보를 활용한 입체 편집 프로세스 연구)

  • Baek, Kwang-Ho;Kim, Min-Seo;Han, Myung-Hee
    • Journal of Digital Contents Society
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    • v.13 no.2
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    • pp.225-233
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    • 2012
  • The 3D stereoscopic image contents have been emerging as the blue chip of the contents market of the next generation since the . However, all the 3D contents created commercially in the country have failed to enter box office. It is because the quality of Korean 3D contents is much lower than that of overseas contents and also current 3D post production process is based on 2D. Considering all these facts, the 3D editing process has connection with the quality of contents. The current 3D editing processes of the production case of are using the way that edits with the system on basis of 2D, followed by checking with 3D display system and modifying, if there are any problems. In order to improve those conditions, I suggest that the 3D editing process contain more objectivity by visualizing the depth data applied in some composition work such as Disparity map, Depth map, and the current 3D editing process. The proposed process has been used in the music drama , comparing with those of the film . The 3D values could be checked among cuts which have been changed a lot since those of , while the 3D value of drew an equal result in general. Since the current process is based on an artist's subjective sense of 3D, it could be changed according to the condition and state of the artist. Furthermore, it is impossible for us to predict the positive range, so it is apprehended that the cubic effect of space might be perverted by showing each different 3D value according to cuts in the same space or a limited space. On the other hand, the objective 3D editing by applying the visualization of depth data can adjust itself to the cubic effect of the same space and the whole content equally, which will enrich the 3D contents. It will even be able to solve some problems such as distortion of cubic effect and visual fatigue, etc.

The essay of Bijeung by chinese doctors in 20th century - Study of - (20세기(世紀) 중의사(中醫師)들의 비증(痺證)에 대(對)한 논술(論述) 연구(硏究) - 《비증전집(痺證專輯)》 에 대(對)한 연구(硏究) I -)

  • Kim, Myung Wook;Oh, Min Suk
    • Journal of Haehwa Medicine
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    • v.9 no.1
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    • pp.547-594
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    • 2000
  • I. Introduction The essence of Oriental medicine consists of ancient books, experienced doctors and succeeded skills of common society. Many famous doctors studied medical science by their fathers or teachers. So the history of medical science is long. $\ll$DangDaeMyeongIImJeungJeongHwa(當代名醫臨證精華)$\gg$ written by SaWoogWang(史宇廣) and DanSeoGeon(單書健) has many medical experience of famous doctors. So it has important historical value. Bi(痺) means blocking. BiJeung is one kind of symptoms making muscles, bones and jonts feel pain, numbness or edema. For example it can be gout or SLE etc. So I studied ${\ll}BiJeungJuJip{\gg}$. II. Final Decision Following decisions of Chinese doctors of 20th century are as follows ; 1. JuYangChun(朱良春) emphasized on IkSinJangDok(益腎壯督) to treat BiJeong. And he devided WanBi(頑痺) as PungHanSeup(風寒濕), DamEo(痰瘀), YeolDok(熱毒), SinHeo(腎虛). He used insects for medicine. 2. ChoSuDoek(焦樹德) introduced past prescription. He used ChiBiTang(治痺湯) to treat HaengBi(行痺), TongBi(痛痺), ChakBi(着痺). He insisted that Han(寒; coldness) and Seup(濕; dampness) be Eum(陰) and Pung(風; wind) can change his character to be Eum. After all BiJeung is usually EumJeung. So he used GaeJi(桂枝) and BuJa(附子). By the way he used ChungYeolSanBiTang(淸熱散痺湯) for YeolBi, BoSinGeoHanChiWangTang SaBok(王士福) emphasized on the importance of medicine. He introduced many treatments like CheongYeol(情熱) for YeolBi and YiO(二烏) for HanBi. And he divided BiJeung period for three steps. At 1st step, we must use GeoSa(祛邪), at 2nd step, we must use BuJeong(扶正) and at 3rd step, we must use BoHyeol(補血), he insisted. And he introduced many herbs to treat BiJeung. 4. JeongGwangJeok(丁光迪) said that GaeJi(桂枝), MaHwang(麻黃), OYak(烏蘖) and BuJa(附子) are very important for TongRak(通絡). And pain usually results from Han(寒), so he liked to use hot-character herbs. 5. MaGi(馬志) insisted that BiJeung usually result from ChilJeong(七情). And he liked to use insects for treatment of BiJeung. 6. WeolSeokMu(越錫武) introduced 8 kinds of treatments and divided BiJeung period. Also he divided BeJeung for PungBi(風痺), HanBi(寒痺) and SeupBi(濕痺). 7. SeoGeaHam(徐季含) observed many patients and concluded that 86.7% of BiJeung is HeuJeung(虛症). 8. YuJiMyeong(劉志明) said that YeolBi is important and CheongYeol is also important. So he emphasized on DangGyuiJeomTongTang(當歸拈痛湯) and SeonBiTang(宣痺湯). 9. WangLiChu(汪履秋) studied cause of WanBi. Internal cause is GiHyeolHeo(氣血虛) and GanSinHeo(肝腎虛) and external cause is SaGi(邪氣) he insisted. 10. WangSaSang(王士相) said that YeolBi can be SeupYeolBi or EumHeuYeolBi(陰虛熱痺) and HanSeupBi(寒濕痺) is rare. He use WooBangJaSan(牛蒡子散) and BangPungHwan(防風丸) for SeupYeolBi, DangGyuiSaYeokTang(當歸四逆湯) for HanSeupBi. 11. JinTaekGang(陳澤江) treated YeolBi with BaekHoGaGyeJiTang(自虎加桂枝湯) and SaMyoSan(四妙散). If they don't have effect, he tried to cure BiJeung step by step. And he used e term of GeunBi(筋痺) and BangGiMogwaEIInTang(防己木瓜薏苡仁湯) was good for GeunBi. 12. MaSeoJeong(麻瑞亭) said that PungSeupYeokJeul(風濕歷節) is BiJeung and it is related to GanBinSin(肝脾腎; liver, Spleen, Kindey). And he emphasized on balance WiGi(衛氣) and YoungHeul(營血). 13. SaJeJu(史濟桂) said that GeunGolBi(筋骨痺) is similar to arthritis and sometimes called ChakBi. And SinBi(腎痺) is terminal stage of ChakBi, he said. He also used insects for treatment. 14. JeongJeNam(丁濟南) tried to cure SLE and used GyeJi, CheonCho(川椒), SinGeunCho(伸筋草), SunRyeongBi(仙靈脾), HyconSam(玄蔘) and GamCho(甘草). 15. JinGYungHwa(陳景和) emphasized on diagnosis of tongue. If the color of tongue is blue, it usually has EoHyeol(瘀血), for example. And he also used insects. 16. JuSongI(朱松毅) tried to devide YeolBi with OnByeong(溫病), Wi(衛), Gi(氣) and Hyeol(血). 17. RuDaBong(蔞多峰) said that JyeongHeo(正虛), OiSa(外邪) and EoHyeol are closely related. And he explained BiJeung by deviding the body into the part, for example head, neck, shoulder, waist, upper limb and lower limb. 18. YuMuBo(劉茂甫) defined PungHanSyubBi as chronic stage and YeolBi as acute stage.

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Inhibition of Urea Hydrolysis and Nitrification in Upland Soils by Artemisia asiatica Extracts (쑥 추출물(抽出物)의 밭토양중(土壤中) 요소분해(尿素分解), 질산화(窒酸化) 작용(作用) 억제효과(抑制效果))

  • Lim, Sun-Uk;Shin, Myonug-Ho;Park, Hyun-Jun;Kim, Min-Kyun
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.4
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    • pp.392-399
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    • 1998
  • Nitrogen fertilizers such as urea are readily hydrolyzed in soils to produce ammonium ions which pass through nitrification and denitrification processes. These serial processes have drawn attention due to nitrogen losses, eutrophication, blue baby syndrome, and ozone depletion problems. The purpose of this study was to test the inhibitory effects of hot-water extract and organic solvent fractions of Artemisia asiatica leaves on soil urea hydrolysis and nitrification. In addition, the effects of organic solvent fractions on urease activity and ureolytic bacterial population were also investigated. First, hot-water extract of Artemisia asiatica leaves inhibited soil nitrification substantially with a marginal stimulatory effect on soil urea hydrolysis. Soils treated with hot-water extract of Artemisia asiatica leaves showed significant decreases in the accumulation of soil $NO_3-N$ (~68% decrease) compared with the control soil without the treatment of hot-water extract. In contrast, $CHCl_3$/MeOH fraction and basic aqueous layer of Artemisia asiatica leaves inhibited soil urea hydrolysis very strongly, causing 5.8 and 4.3-fold higher accumulation in amounts of remaining urea-N compared with the non-treated soil. Meanwhile, non of the organic solvent fractions showed any significant effects on soil nitrification inhibition. The inhibition of ureolytic bacterial activity by $CHCl_3$/MeOH fraction and aqueous basic layer of Artemisia asiatica leaves without any effects on urease activity itself led us to conclude that the inhibitions of soil urea hydrolysis were caused by the antagonistic effects on ureolytic bacterial activity.

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