• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.448-468
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• 1996

To maintain its functional integrity, bone is continuously remodelled by a process involving resorption by osteoeclasts and formation by osteoblasts, In order to respond to changes in the physical environment or to trauma with the relevant action, this process is strictly regulated by locally synthesized or systemic fators, Prostaglandin $E_2(PGE_2$) is perhaps one of the best studied factors, having been known to affect bone cell function for several decades.$PGE_2$ has both anabolic and catabolic activities. Excess of $PGE_2$ has been implicated in a number of pathological states associated with bone loss in a number of chronic inflammatory conditions such as periodontal disease and rheumatoid arthritis. $PGE_2$ and other arachidonic acid metabolites have been shown to be potent stimulators of osteoclastic bone resorption in organ culture. The anabolic effects of $PGE_2$ were first noticed when an increase in periosteal woven bone formation was seen after the infusion of $PGE_2$ into infants in order to prevent closure of the ductus arteriosus. The cellular basis for the catabolic actions of $PGE_2$ has been well characterized. $PGE_2$increases osteoclast recruitment in bone marrow cell cultures. Also $PGE_2$ has a direct action on osteoclast serving to inhibit activity and can also indirectly activate osteoclast via other cells in the vicinity, presumably osteoblast. The cellular mechanisms for the anabolic actions of $PGE_2$ are not nearly so well understood. The purpose of this paper was to study the effects of $PGE_2$ and dibutyl(DB)cAMP on osteoblastic clone MC3T3El cells and on the generation of osteoclasts from their precursor cells. The effect of $PGE_2$ and DBcAMP on the induction of alkaline phoaphatase(AlP) was investigated in osteoblastic clone MC3T3El cells cultured in medium containing 0.4% fetal bovine serum. $PGE_2$ and DBcAMP stimulated ALP activity and MTT assay in the cells in a dose-dependent manner at concentrations of lO-SOOng/ml. Cycloheximide, protein synthesis inhibitor, inhibited the stimulative effect of $PGE_2$ and DBcAMP on ALP activity in the cells. $PGE_2$also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 500ng/ml. The effect of $PGE_2$ on the generation of osteoclasts was investigated in a coculture system of mouse bone marrow cells with primary osteoblastic cells cultured in media containing 10% fetal bovine serum.After cultures, staining for tartrate-resistant acid phosphatase(TRAP)-marker enzyme of osteoclast was performed. The TRAP(+) multinucleated cells(MNCs), which have 3 or more nuclei, were counted. More TRAP(+) MNCs were formed in coculture system than in control group. $PGE_2(10^{-5}10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in culture. $PGE_2(10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in coculture of osteoblastic clone MC3T3E1 cells This results suggest that $PGE_2$ stimulates the differentiation of osteoblasts and generation of osteoclast, and are involved in bone formation, as well as in bone resorption.

• The Korean Journal of Air & Space Law and Policy
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• v.23 no.2
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• pp.173-205
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• 2008

Space debris have frequently caused damage to space objects like satellites in orbits and sometimes have fallen on the earth. Such increase in space debris will lead to the high possibility of threatening space activities of mankind. However, it is not so easy for the damage caused both by identified and by unidentified space debris to be recovered since in the regime of the current international law, there is no legislation of prescribing the damage done by space debris. For overcoming the limitation it seems desirable that either the Liability Convention should partly be amended or new international law regime should be established. For instance, 'space debris' should be included in the new definition of 'space object' and the range of launching should also be defined clearly by making the concept of 'launching' somewhat more specified. Moreover, the subject of international liability for damage caused by space debris should be divided into two classes: the subject before and after registration. While in case of before-registration launch states should be held liable for any damage jointly or individually, in case of after-registration 'the state of registry' or 'owner' of the space debris should be. In the event of damage being caused elsewhere than on the surface of the earth to a space object of other State, 'fault-based liability' is currently applied. But it needs to be changed into 'absolutely liability'. In this paper, 'Liability Pool', 'Insurance', 'Market-Share Liability' are presented as aid devices of the damages resulting from unidentified space debris. They should be defined through the amendment of the Liability Convention or another international treaty. Some day there comes a time when our country shall possess many of the astronomical price of satellites. It means that we can't be free from the damage by the increasing number of space debris. Provided that our satellites are damaged by such space debris, it will do the satellites damage and cause impaired functioning or troubles in operation. As a result, if we are not paid for the damage by space debris, we will be confronted with tremendous economic loss because it is necessarily connected with the excess burden of taxation. Thus, an international agreement regarding the measures of the compensation for space debris damage must be made very soon.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.2
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• pp.119-130
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• 1999

After preparing $Mg_2Ni_{1-x}{^{57}}Fe_x$(x=0.015, 0.03, 0.06, 0.12 and 0.24) alloys, they were studied by $M{\ddot{o}}ssbauer$ resonance. The $M{\ddot{o}}ssbauer$ spectra of x=0.015 and 0.03 alloys exhibit two doublets (doublet 1, 2). That of x=0.06 alloys shows two doublets (doublet 1,2) and one six-line, and those of x=0.12 and 0.24 alloys have only one six-line. The doublet 1 for x=0.015, 0.03 and 0.06 alloys is considered to result from a fraction of Fe in excess showing a superparamagnetic behavior. The doublet 2 is considered to result from the Fe substituted for Ni in the $Mg_2Ni$ phase. The values of isomer shift 0.24 ~ 0.28 mm/s suggest that the iron exist in the state $Fe^{+3}$. The result that the quadrapole splitting of the doublet 2 is not zero shows that the distribution of electrons around the iron is asymmetric. Their values for the doublet 2, 1.20 ~ 1.38 mm/s, approach the value of quadrapole for the oxidation number +3. The six-line showing the magnetic hyperfine interactions results from the iron which has not substituted the nickel in the $Mg_2Ni$ phase. The $M{\ddot{o}}ssbauer$ spectra of the hydrided alloys with x=0.015 and 0.03 show six-line. This suggests that the iron segregates with the hydriding reaction. The analysis results of the $M{\ddot{o}}ssbauer$ spectrum, the variation of magnetization with magnetic field, Auger electron spectroscopy and electron diffraction show the segregation of Ni and the formation of MgO. This is considered to result from the reaction of the $Mg_2Ni$ phase with the oxygen contained in the hydrogen as impurity.

• Journal of Korean Medical Ki-Gong Academy
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• v.4 no.2
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• pp.153-186
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• 2000

Jigam(止感), Josik(調息), Kumchock(禁觸), from the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) treat three elements of Kigong, regulation of mental activties, regulation of breathing and adjustment of posture and there are some similar mentions with the view of human body based on oriental medicine like those Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境) ect. Thus as a result of comparison and observation about the interrelationships between principle of Kigong in the lecture on Truth of ${\ll}Samilshingo{\gg}$(三一神誥) and oriental medicine. I have conclusion as follows. 1. According to the lecture on Truth, the components of human body are the one and only Samjin(三眞), Sammang(三妄) and Samdo(三途) resulted from facing Samjin(三眞) to Sammang(三妄) and Sippalkyoung(十八境). This fact presents the principle of human change. 2. the principle of Kigong mentioned in the lecture on Truth shows the original Ilshin(一神) on the basis of Samjin(三眞), Sammang(三妄), Samdo(三途) and Sippalkyoung(十八境). This makes common, unity and sound Sim(心), Ki(氣) and Shin(身), Sammang(三妄) through Jigam(止感), Josik(調息) and Kumchock(禁觸), be versed, intellected and guaranteed Sung(性), Myoung(命) and Jung(精), Samjin(三眞) and emit Kyun(見), Mun(聞), Ji(知) and haeng(行), Sadaeshingi(四大神機) and finally all these are harmonized into Duk(德), Hye(慧) and Ryuk(力), Samdae(三大) which is the entity of God. 3. Samsipyookjongmyowhasang(三十六種妙化相) is an ascetic practice done after a chulin(哲人) deduce Ji(止), Jo(調) and Kum(禁), Sambup(三法) on the basis of the lecture on Truth. So I suppose it correlates nature's six elements. Kong(空)(Chun(天)). Yol(熱)(Wha(火)). Jin(震(Jeon(電)), Seup(濕)(Shoo(水)), Han(寒)(Poong(風)) and Ko(固)(Ji(地)), human's Samjin(三眞), Sung(性), Myoung(命) and Jung(精) and Sammang(三妄), Sim(心), Ki(氣) and Shin(身) and makes clear the principle of discipline. 4. In comparison with Samjin(三眞) and Sammang(三妄) says from the lecture on Truth and the Three Essential Elements of the body construction(三寶) from oriental medicine, Samjin(三眞) and Sammang(三妄) as factors of human body in the concept of practical knowledge. That is the one and only Samjin(三眞) in terms of the Three Essential Elements of the body construction(三寶) is considered a structural principle for every single person and Sammang(三妄) is considered a functional form for each individual. And it can be Sung(性)+Sim(心)=Spirit(神), Myoung(命)+Ki(氣)=Vital Force(氣) and Jung(精)+Shin(身)=True Essence(精). 5. In comparison with Sippalkyoung(十八境) of Samdo(三途) from the lecture on Truth and three medical causes of disease, Gamdoyookkyoung(感途六境) is similar with endopathic cause caused by Naesangchiljung(內傷七情), Sikdoyukkyoung(息途六境) is similar with exopathic cause by six climatic conditions in excess as pathogenic factors(六淫) and Yoegi(?氣) and Chokdoyukkyoung(觸途六境) is similar with non-endo-exopathogenic causes by diet imbalance, fatigue, intemperance in sexual life and trauma etc. 6. In the lecture on Truth, the Chulin(哲人) who discipline Sambup(三法), Sangchul(上哲), Choongchul(中哲) and Hachul(下哲) can be compared with Kigong expert(health preserving expert) such as the Spiritual Men(眞人), the Sapients(至人), the Sages(聖人) and the Men of Exellent Virtue(寶人) in the Sang Gu Tian Zhen Lun of the Huang Ti Nei Ching Su Wen(素問 上古天眞論) and then Sangchul(上哲) is the Spiritual Men(眞人), Choongchul(中哲) is the Sapients(至人) and Hachul(下哲) is the Sages(聖人) while the men of Exellent Virtue(賢人) is inferior to Chulin(哲人) when he goes to extremes.

• KSBB Journal
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• v.19 no.2
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• pp.93-97
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• 2004

We investigate the effect of enzyme pretreatment using protease, carbohydrase, and lipase on improvement of sludge treatment efficiency by measuring SCOD and TCOD. The enzyme-pretreatment increases SCOD of excess sludge. In addition, the amount of sludge reduction during digestion, in terms of SCOD and TCOD, are enhanced by enzyme-pretreatment. Among pretense, carbohydrase, and lipase, pretense showed the best enhancement of the sludge treatment efficiency. Sludge digestion followed by ozone and enzyme treatments showed more effective sludge treatment when compared with ozone treatment alone. Therefore, we expect that enzyme pretreatment can be used as a useful tool for enhancing the sludge treatment efficiency.

• Clean Technology
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• v.20 no.4
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• pp.390-397
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• 2014

This study was performed to investigate the effects of fluidizing media on $N_2O$ production in fluidized bed incineration of sewage sludge. The fluidized media were prepared in a form of 2 mm bead by mixing zeolite powders in our lab. Sand having 0.4 mm of the mean size showed 0.44 m/s of minimum fluidization velocity ($U_{mf}$), while the prepared zeolite media 0.5 m/s. When the ratio of fluidizing media height to the inside diameter of the incinerator (bed aspect ratio) increased from 1.4 to 3.1, it was found that $U_{mf}$ of the zeolite media was varied from 0.5 m/s to 0.7 m/s. Under the operation conditions in 1.79 of excess air ratio, $909^{\circ}C$ of bed temperature and ca. 1.65 m/s of superficial velocity, as the weight of fluidizing meadia was increased, $O_2$ concentration in the flue gas was slightly decreased, and $CO_2$ increased. Above 6 kg of fluidizing media weight (1.98 of bed aspect ratio), it was observed that $N_2O$ concentration was significantly reduced, which might result from the decomposition of $N_2O$ on the zeolite media rather than transformation of $N_2O$ to NOx. On the other hand, in a variation of the zeolite media mixing ratio to sand and bed temperature at a constant total bed height, significant difference was exhibited in $N_2O$ emission concentration according to the temperature. Considering the operation temperature in the incineration, the effective calcination temperature of the zeolite media was suggested to be around $900^{\circ}C$.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.298-304
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• 2012

This study was carried out to investigate the effects of various thawing methods on the physical and microbiological properties of frozen pork. The frozen pork was thawed using four methods: refrigerator, cold water, room temperature, and microwave oven. Changes in physicochemical properties of thawed pork were analyzed by measuring color, pH, thawing loss and thiobarbituric acid reactive substances (TBARS) values. Changes in the microbiological properties of thawed pork were analyzed by counting total aerobic bacteria and coliform group. L values of thawed pork were significantly increased by all thawing methods for normal thawing time except the uncooked portion of thawed pork via a microwave. However, the a value decreased in pork thawed by all thawing methods. pH values significantly increased in the pork thawed by microwave and by applying two times the normal thawing time. After thawing, thawing loss was highest in the pork thawed at room temperature for two times the normal thawing time. In addition, TBARS values also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. The total aerobic bacteria count significantly increased in the case of microwave thawing for normal thawing time and it also increased in the pork thawed in a refrigerator and at room temperature for two times the normal thawing time. These results demonstrate that refrigeration and cold water thawing are the most suitable for frozen pork, and that excess thawing should be avoided.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.651-658
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• 2004

Runx2 is a transcription factor in homologous with Drosophila runt gene and it is essential for bone formation during embryogenesis and a critical gene for osteoblast differentiation and osteoblast function. Runx2-haploinsufficency causes cleidocranial dysplasia (CCD). CCD is an autosomal-dominant inherited disorder characterized by hypoplastic clevicle and delayed ossification in fontanelles and wormian bones. Dental defects are possibly shown to CCD patients : multiple supernumerary teeth, irregular and compressed permanent tooth crowns, hypoplastic and hypomineralized defects in enamel and dentin, an excess of epithelial root remnants, the absence of cellular cementum, and abnormally shaped roots. In addition, delayed eruption of the secondary dentition is a constant finding. The aim of this study is to evaluate the role of Runx2 in the tooth development and eruption through analyzing the expression pattern of Runx2 by in situ hybridization during crown (late bell stage) and root formation of tooth, using postnatal day 1, 4, 7, 14 and 21 mice mandibular molar teeth. mRNA of Runx2-full length is expressed in dental follicle and surrounding tissue at postnatal day1 and 4. At postnatal day 7, it is expressed in ameloblasts of occlusal surface of enamel and bone area surrounding the tooth. In comparison with previous stage, at postnatal day 14, it is expressed in ameloblasts of proximal surface of enamel. At postnatal day 21 it's expression is observed only in bone area. mRNA of Runx2-typeII is not expressed. At postnatal day 1 and 7. At postnatal day 14 and 21, it's expression is observed in the bone area. In this study, we suggest that Runx2 have a relation of ameloblasts differentiation and an important role to tooth eruption made by dental follicle during intraosseous eruption stage. Also we can confirm that Runx2 has a role to bone formation.

• Journal of Aquaculture
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• v.13 no.2
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• pp.169-174
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• 2000

Reproductive cycle of U. unicinctus was studied from September 1998 to August 1999, using gonadosomatic index (CSI) as an indicator. In November, the CSI values were maximum for male (6.2) and female (7.0), respectively; the values were lowest for them (1.0 and 0.5) during the successive february. Subsequently, they rapidly increased and attained peak by March-April. The values decreased again in both sexes and remained unchanged until August. The index increased in October to attain the peak by November. The CSI values clearly indicated that there are two spawning events in a year, namely the first one during April-May and the second one in December. Reproductive cycle was classified into the following successive stages: in female, multipication (January~February, June ~Setember), maturation (March~April, November), spent (May and December), degeneration and resting (June and January), and in male, multiplication January ~ february, June ~September), maturation (March~April, October~November), spent (May and December) and degeneration and resting (January and June). Histological observations revealed that oocytes in the ovary matured simultaneously in November and March. At the same time, the envelopes of matured testis became thinner than those in the early stage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1278-1285
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• 2017

Accumulation of excess low density lipoprotein (LDL) cholesterol in the blood can initiate and accelerate atherosclerosis. Statins mediate the transactivation of proprotein convertase subtilisin/kexin type 9 (PCSK9), which in turn limits their cholesterol-lowering effects via LDL receptor (LDLR) degradation. The objective of this study was to investigate whether or not Allium tuberosum (AT) regulates LDLR and PCSK9. Mice were fed a low fat control diet (LD) or Western diet (WD) supplemented with AT (1%, w/w). AT significantly attenuated total and LDL cholesterol levels in mice fed WD (P<0.05). AT also significantly inhibited hepatic PCSK9 gene expression (P<0.05) while AT maintained hepatic LDLR gene expression. To further investigate AT-mediated PCSK9 regulation, HepG2 cells were treated with 10% delipidated serum (DLPS) in the presence or absence of AT. Non-toxic level of AT dose-dependently increased the LDLR protein level, and AT at $400{\mu}g/mL$ markedly inhibited PCSK9 protein expression. Similarly, AT significantly increased LDLR gene expression, whereas it significantly down-regulated PCSK9 gene expression. AT-mediated reduction of PCSK9 gene expression is likely due to decreased hepatic nuclear factor $1{\alpha}$ ($HNF1{\alpha}$) expression, but not SREBP2 in HepG2 cells under lipid-depleted conditions. AT-mediated PCSK9 inhibition contributed to LDLR protein stabilization via protection against LDLR lysosomal degradation in HepG2 cells under lipid-depleted conditions. Further investigation is warranted to determine the active components of AT and whether or not these components are effective in reducing hypercholesterolemia.