• Horticultural Science & Technology
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• v.29 no.3
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• pp.187-194
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• 2011

The objective of this study was to determine the effects of light intensity and electrical conductivity (EC) of nutrient solution on the growth and nutrient uptake of potted kalanchoe plants (Kalanchoe blossfeldiana 'Marlene') with growth stage in ebb and flow subirrigation systems. The plants were grown at four ECs of 0.5, 1.0, 1.5, and 2.0 $dS{\cdot}m^{-1}$ for seedling stage and four ECs of 1.0, 1.5, 2.0, and 3.0 $dS{\cdot}m^{-1}$ for short day stage under three daily photosynthetic photon flux (PPF) of 6.5, 10.3, 18.2 $mol{\cdot}m^{-2}{\cdot}d^{-1}$. At seedling stage, plant height was the longest under the lowest light intensity, and particularly dry weights and leaf areas were the highest at PPF 10.3 $mol{\cdot}m^{-2}{\cdot}d^{-1}$. Dry weights and leaf areas were the highest at EC 1.5 $dS{\cdot}m^{-1}$ regardless of light intensity. At short day exposure, plant height was the longest under the lowest light intensity. Dry weights, leaf areas, and number of pedicels of the plants significantly increased as light intensity increased. Under all light intensity conditions, dry weights, leaf areas, and number of pedicles increased until EC becomes to 1.0 - 2.0 $dS{\cdot}m^{-1}$. And after reached the highest at EC 2.0 $dS{\cdot}m^{-1}$, they decreased at EC 3.0 $dS{\cdot}m^{-1}$. By comparing the ion uptakes at EC 1.5 $dS{\cdot}m^{-1}$ of seedling stage and EC 2.0 $dS{\cdot}m^{-1}$ of short day stage in which the plants grew better, we confirmed that ion balance of nutrient solution among $NO_3{^-}$-N, $H_2PO_4{^-}$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were significantly changed at short day stage compared to seedling stage. For better growth of the plants, both ion balance and EC of nutrient solution should be considered under different light intensities at short day stage while control of EC is enough at seedling stage.

• Journal of Periodontal and Implant Science
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• v.31 no.3
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• pp.555-564
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• 2001

The purpose of this study is to evaluate the bioresorbability of Calcium Polyphosphate added with $Na_2O$ and chitosan. Though calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To solve these problem, we developed a new ceramic, calcium polyphosphate(CPP), and report the biologic response to CPP in extraction sites of beagle dog. Porous CPP granules were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. CPP granules added with $Na_2O$ and chitosan were implanted in extraction sockets and histologic observation were performed at 12 weeks later. Histologic observation at 12 weeks revealed that CPP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CPP granules added with chitosan were well adatped without any adverse tissue reaction and resorbed slowly and spontaneously. CPP granules added with $Na_2O$ and chitosan show multinucleated giant cells and osteoblast-like cells around grafted material and newly formed bone. This result revealed that CPP, regardless of its additive component, had a high affinity for bone and had been resorbed slowly. From this results, it was suggested that CPP is promising ceramic as a bone substitute and addition of $Na_2O$ and chitosan help biodegradation. In further study , it will be determined which concentration of $Na_2O$ help biodegradation and the other additive components increase the degradation rate.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.89-94
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• 2004

Callus of Rhodiola sachalinensis A. Bor were induced from leaf explant on l/2MS solid supplemented with combination of auxin (2.4-D, NAA: 0.1∼2mg/L) and cytokinin (BA: 0.1∼0.2mg/L). The effects of various medium, culture conditions and phytohormones on the growth of callus were investigated. MS, WPM, B$_{5}$ medium and diluted or concentrated media (1/2X, 2X, 3X) were used to investigate the growth of callus on each media. Among these, the highest growth was observed when cultured in in 2B$_{5}$ medium containing 0.5mg/L NAA and 1mg/L BA, 3％ sucrose and 49.6 mM KNO$_3$ as nitrogen source, and 2.16mM NaH$_2$PO$_4$ as phoshate source at $25^{\circ}C$ in the dark. The calli cultured with 5％ sucrose produced high salidroside content (0.41％ on the basis of dry wt) than normal root (0.17％).

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.185-185
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• 1994

관상동맥은 전기적으로 자극하여도 활동전위가 쉽게 유발되지 않는 조직인데, 이는 세포내의 $Ca^{2+}$에 의해서 활성화되는 $K^{+}$통로때문이라고 여겨지고 있다. 저자들은 단일 이온통로 수준에서 이러한 관상동맥 $K^{+}$ 통로의 성질을 조사하고, 아울러 $K^{+}$ 통로 개방제를 포함한 몇가지 약물이 $K^{+}$ 통로에 미치는 영향을 알아보고자 본 연구를 수행하였다. 막소포는 돼지의 심장에서 관상동맥을 분리하여 균질화 및 원심분리하여 준비하였으며, sucrose 20/30%에 있는 층을 취하여 분주한 후 -7$0^{\circ}C$로 보관하여 사용하였다. 평지방막은 1-palmitoyl, 2-oleoyl-phosphatidyl ethanolamine과 1-palmitoyl, 2-oleoyl phosphatidylcholine (4:1)을 n-decane에 녹인지방액(25mg/m1)을 200 $\mu\textrm{m}$의 구멍에 칠하여 만들었다. 단일 $K^{+}$ 통로는 막소포 (1-5$\mu\textrm{g}$/ml)를 평지방막의한쪽에 추가하고 자석으로 저어 융합이 되도록 하였으며, 통로의 활성은 막의 양쪽에 150 mM KCI, 10 mM HEPES-KOH, 0.5 mM EGTA, 0.6 mM $CaCl_2$ (pH 7.2)로 된용액이 존재하는 상태에서 막전압을 다르게 하며 기록하였다. 단일 이온 통로 전류는 amplifier를 통하여 VCR tape에 녹화하여 후에 분석에 이용하였으며, 동시에 종이기록지에 기록하였다. 단일이온통로 활성의 분석은 pClamp (Ver5.5)를 이용하여 수행하였다. 관상동맥에서 가장 흔히 기록되는 이온통로는 막전압과 $Ca^{2+}$의 농도에 의하여 변하는 $K^{+}$ 통로이었는데 pCa 4.0과 -10 mV에서 초기 활성도(Po)는 0.1에서 0.8까지 다양하였다. 전류와 전압과의 관계는 -60 - +60mV의 전압범위에서 직선형이었다.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.183-196
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• 1998

The purpose of this study was to determine the effect of bleaching technique on the shear bond strength of esthetic restorative materials to bovine enamel. The bleaching agent was used 35% $H_2O_2$(Hi-Lite, Shofu, U.S.A.). Experimental groups were divided into two divisions as group A and B. Experimental A groups for the effect of number of bleaching were as follows ; Group Al : no bleaching Group A2 : bleaching 1 time ( for 5 minutes ) Group A3 : bleaching 3 times ( each for 5 minutes ) Group A4 : bleaching 6 times ( each for 5 minutes ) Group A5 : bleaching 9 times ( each for 5 minutes ) Experimental B groups for the effect of storage period in artificial saliva were as follows ; Group B1 : not stored in artificial saliva after bleaching Group B2 : stored in artificial saliva for 1 day after bleaching Group B3 : stored in artificial saliva for 1 week after bleaching Group B4 : stored in artificial saliva for 2 weeks after bleaching Group B5 : stored in artificial saliva for 4 weeks after bleaching Composite resin and glass ionomer cement were bonded to all specimens, and the shear bond strength between enamel and r~storative material were measured in Instron Universal Testing Machine(Instron, 4467, U.S.A,), Additionally, the bleached enamel specimens were examed after etching with 37.4% $H_3PO_4$ for 1 min under SEM(S-2300, Hitachi Co., Japan) to observe the effect of bleaching procedure on enamel surface morphology. The result were as follows ; 1. In SEM findings, bleached bovine enamel was found to be superficially rough. 2. In bleached bovine enamel, the effect of acid etching was reduced with the increase of number of bleaching. 3. The mean shear bond strength of composite resin and glass ionomer cement to bleached enamel surface tended to be lower than those to non-bleached enamel surface. 4. With the increase of number of bleaching, the shear bond strength of composite resin and glass ionomer cement to bleached enamel were progressively decreased. 5. Increasing the, storage period in artificial saliva after bleaching, the shear bond strength of composite resin and glass ionomer cement to bleached enamel were progressively increased. 6. The mean shear bond strength of glass ionomer cement to bleached bovine enamel tended to be clearly lower than that of composite resin.

• Korean Journal of Materials Research
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• v.22 no.9
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• pp.482-488
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• 2012

To fabricate a precise micro metal mold, the electrochemical etching process has been researched. We investigated the electrochemical etching process numerically and experimentally to determine the etching tendency of the process, focusing on the current density, which is a major parameter of the process. The finite element method, a kind of numerical analysis, was used to determine the current density distribution on the workpiece. Stainless steel(SS304) substrate with various sized square and circular array patterns as an anode and copper(Cu) plate as a cathode were used for the electrochemical experiments. A mixture of $H_2SO_4$, $H_3PO_4$, and DIW was used as an electrolyte. In this paper, comparison of the results from the experiment and the numerical simulation is presented, including the current density distribution and line profile from the simulation, and the etching profile and surface morphology from the experiment. Etching profile and surface morphology were characterized using a 3D-profiler and FE-SEM measurement. From a comparison of the data, it was confirmed that the current density distribution and the line profile of the simulation were similar to the surface morphology and the etching profile of the experiment, respectively. The current density is more concentrated at the vertex of the square pattern and circumference of the circular pattern. And, the depth of the etched area is proportional to the current density.

• Journal of Environmental Science International
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• v.13 no.3
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• pp.245-250
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• 2004

The SBR(Sequencing Batch Reactor) process is ideally suited to treat high loading wastewater due to its high dilution rate. SBR operates by a cycle of periods consisting of filling, reacting, settling, decanting and idling. The react phases such as aeration or non-aeration, organic oxidation, nitrification, denitrification and other bio-logical reactions can be achieved in a reactor. Although the whole reactions can be achieved in a SBR with time distributing, it is hard to manage the SBR as a normal condition without recognizing a present state. The present state can be observed with nutrient sensors such as ${NH_{4}}^{+}-N$, ${NO_{2}}^{-}-N$, ${NO_{3}}^{-}-N} and ${PO_{4}}^{ 3-}-P.$ However, there is still a disadvantage to use the nutrient sensors because of their high expense and inconvenience to manage. Therefore, it is very useful to use common on-line sensors such as DO, ORP and pH, which are less expensive and more convient. Moreover, the present states and unexpected changes of SBR might be predicted by using of them. This study was conducted to get basic materials for making an inference of SBR process from ORP(oxidation reduction potential) of synthetic wastewater. The profiles of ORP, DO, and pH were under normal nitrification and denitrification were obtained to compare abnormal condition. And also, nitrite and nitrate accumulation were investigated during reaction of SBR. The bending point on ORP profile was not entirely in the low COD/NOx ratio condition. In this case, NOx was not entirely removed, and minimum ORP value was presented over -300mV. Under suitable COD/NOx ratio which complete denitrification was achieved, ORP bending point was observed and minimum ORP value was under -300m V. Under high COD/NOx ratio, ORP bending point was not detected at the first subcycle because of the fast denitrification and minimum ORP value was under -300mV at the time.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.311-319
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• 2003

치주조직재생을 도모하기 위한 전통적인 시술방법으로는 여러 가지 골이식재를 이용한 골이식술이 오래 전부터 이용되고 있다. 이번 실험의 목적은 장,단기간의 신생골의 형성과 CPP의 흡수를 비교하여 골이식재로서 Calcium Polyphosphate(CPP)를 평가하는 것이다. 이번 실험에 사용된 CPP는 무수 $Ca(H_2PO_4)$를 condensation하여 무결정의 $Ca(PO_3)_2$를 얻고 이를 용융하고 냉각시킨후 분쇄하여 얻은 것으로 키토산이나 $Na_2O$를 첨가한 후 3세된 비글견에 이식하여 관찰하였다. 양성 대조군으로 동결탈회건조골을 이용하였다. 조직학적으로 3개월 소견과 같이 섬유조직의 게재없이 신생골의 형성이 관찰되었다. 12개월 후의 신생골의 형성은 3개월 결과에 비해서 동결탈회건조골이나 키토산, $Na_2O$를 넣은 CPP 과립에서 더 많은 비율로 나타났다. 음성 대조군과 이식재를 넣은 군간에는 유의성이 있는 것으로 나타났고(p<0.05), 또한 키토산을 첨가한 CPP 과립과 $Na_2O$를 첨가한 CPP 과립 사이에는 신생골의 형성에 유의성이 없었다. 이식한 CPP 과립의 경우 흡수소견이 3개월 결과에 비해 크게 증가하지 않았다. 이번 실험에서는 첨가물에 상관없이 CPP 과립은 골유도성과 생체적합성을 보였다. 그러나 흡수속도가 매우 느려 신생골로 대체되는 여부를 알 수 없었다. 향후 연구에서는 흡수속도를 증가시킬 수 있는 적당한 CPP 형태와 첨가물을 밝혀내어야 할 것이다.

• Journal of Aquaculture
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• v.8 no.2
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• pp.117-131
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• 1995

In order to improve the present running seawater system for seedling production of marine fishes, rearing experiments with the juveniles of black seabream (Acanthopagrus schlegeli) and oblong rockfish (Sebastes oblongus) were conducted. The recirculating seawater system (F) equipped with the rotating biological contactors and the running seawater system (R) were used. Environmental factors, growth, survival rate and rearing density of the fish were compared between two systems during the experimental period. In the rearing experiment of black seabream, water temperature in F was fluctuated with surrounding air temperature and was higher than that in R. Specific gravity of the rearing seawater in F was relatively stable in the range of 1.0252 to 1.0266, while that in R was greatly fluctuated. pH in F turned out to be 7.51, but pH in R was similar to that in the natural seawater. Dissolved nitrite and nitrate in F were higher than those in R. While no significant differences in the growth of black seabream juveniles were recognized between two systems, survival rates of fishes in F were higher than those of fishes in R. In the rearing experiment of oblong rockfish, water temperature in F was higher than that in R. Specific gravity in F was slightly higher than that in R which showed relatively less fluctuation in the range of 1.0253 to 1.0270. pH in F turned out to be 7.96, but pH in R was similar to that in the natural seawater. Dissolved nitrite and nitrate in F were higher than those in R, but ammonia was lower in F. The juveniles of oblong rockfish reared in F grew significantly faster in their total length and body weight than those in R (P<0.05). However, survival rates of fishes between two systems showed no significant differences.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.253-263
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• 2002

To test for the effect of applied fertilizer and nutrients on uptake and transport for paddy rice, two paddy field trials were conducted with Dongjinbyeo in degenerated salt paddy field of Jeonbuk series from 1999 to 2000. After experiment, soil acidity, content of organic matter phosphate, silicate, potassium, calcium, and total nitrogen was increased by application of fresh cattle manure(FCM). Content of Nitrogen in soil layer leached inorganic nitrogen $NO_3$ was higher that that of $NH_4$ and was high in treatment of FCM. Content of $PO_4$ was higher in FCM than other treatments. But content of potassium was in high control. During the growth of rice plant, the amount of water consumption was 477mm. The amount of supplied nitrogen was high in treatment of no nitrogen(NN), 20% reduced application of LCU(LCU-20%), and no fertilizer. In case of phosphate, the supplied amount was more than the consumed amount with the exception of treatment "no phosphate(NP) and no fertilizer(NF)". In case of potassium, the consumed amount was more than the supplied amount in all treatments. The amount of applied nitrogen in the nutrient infiltrated water was high in treatment soil test(ST), C+FCM+Si(Silicate) and the ratio of recovered nitrogen was high in 20% reduced application of LCU. The amount of applied phosphate in the nutrient infiltrated water was high in FCM and that of applied potassium was high in 20% reduced application of LCU. Nitrogen use efficiency of paddy rice was high in 20% reduced application of LCU and use efficiency of phosphate and potassium was high in C+Si(Silicate). Grain yield of rice was high in order of 20% reduced application of LCU>C+Si=C+FCM+Si>C+FCM.