• Korean Journal of Materials Research
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• v.17 no.11
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• pp.622-627
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• 2007

Porous poly(e-caprolactone) (PCL) scaffolds were fabricated by salt leaching method. The PCL scaffolds were treated with aqueous NaOH for 0h, 2h, 4h, 8h, and 12h at $40^{\circ}C$. The NaOH-treated PCL scaffolds were dipped in $CaCl_2$ and $K_2HPO_4{\cdot}_3H_2O$ solution alternately three times to induce apatite nuclei onto the surface of the scaffolds. The NaOH-treated PCL scaffolds were immersed into SBF solution for 1day to grow the apatite. The apatite formation were investigated as a fuction of NaOH treatment time. The hydrophilicty and surface area of the PCL scaffolds were increased with NaOH-treatment time. The NaOH-treated PCL scaffolds were successfully formed a dense and uniform bone-like apatite layer after immersion for 1 day in SBF solution.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.466-472
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• 1991

Petroleum ether extracts of panax ginseng C.A. Meyer (GPEE) were tested for the evaluation of anticlastogenic effects against benzo(a)pyrene-induced micronucleated polychromatic erythrocytes using mouse bone marrow micronucleus test. When the GPEE was singly administered before benzo(a)pyrene injection, GPEE showed significant anticlastogenic effect at $50{\sim}200\;mg/kg$. When the GPEE was multiply administered for 5 consecutive days before benzo(a)pyrene injection, GPEE showed potent anticlastogenic effect, even at the low doses, $5{\sim}50\;mg/kg/day$. As a control experiment, GPEE was administered without benzo(a)pyrene injection to demonstrate a clastogenic effect of this extract. When the range of $1{\sim}200\;mg/kg/day$ for 5 consecutive days was administered to mice, it was found that there was no increase of MNPCEs frequency.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1132-1136
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• 2001

A silicon-substituted hydroxyapatite was prepared using tetraethylorthosilicate as a silicon source to obtain a biomaterial having an improved biocompatibility. From the XRD analysis, it was confirmed that a single-phase hydroxyapatite containing silicon was formed without revealing the presence of extra phases related to silicon oxide or other calcium phosphate species. Silicon content was up to 3.32% by weight. Through $\^$29/Si MAS NMR investigation we could confirm the presence of tetrahedral silicate in the framework of hydroxyapatite structure. Substitution of silicon into the hydroxyapatite framework (Ca$\_$10/(PO$_4$)$\_$6-x/(SiO$_4$)$\_$x/(OH)$\_$2-x/ reduced the amount of hydroxyl group to compensate for the extra negative charge of the silicate group, which is confirmed by FT-IR.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.487-495
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• 2004

In order to compare the induced time of osteoporosis between ovariectomized and neurectomized models in ddY mice. Experimental groups were divided into Sham, ovariectomized (OVX group) and neurectomized (NX group) group. The changes of body weight, tibia weight and histomorphometry of epiphyseal regions of tibia that were generally used as criteria index in osteoporosis, were evaluated at 2 and 4 weeks after operations with other generally used index-changes of serum osteocalcin. Also, calcium and phosphorus levels in the ash tibia were demonstrated with their ratio (Ca/P ratio). From the result of this study, evidences which reflect osteoporotic states of animals such as decrease of absolute and relative tibia weight, histomorphometrical index of epiphyseal region of tibia including trabecular bone volume %, and calcium and phosphorous contents in tibia, were generally detected from 4 weeks after ovariectomy and 2 weeks after neurectomy with increase of serum osteocalcin levels. In conclusion, it is considered that more rapid and favorable osteoporosis was induced in neurectomized model compared to that of ovariectomized model.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1638-1642
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• 2006

An experiment was conducted to elucidate the effect of graded levels of vitamin $D_3$ in White Leghorn (WL) layer breeders on egg production, shell quality, hatchability of eggs and juvenile performance of offspring during their late laying period (72-88 wk). White Leghorn breeder females were randomly divided into 5 groups of 50 each and were housed in individual California cages in an open-side housing system. Considering birds in five cages as a replicate, 10 such replicates were randomly allotted to each treatment. A basal diet was formulated containing all the nutrients as recommended for WL layers except vitamin $D_3$, which served as control. Another, four diets were formulated by supplementing graded levels of feed grade crystalline cholecalciferol to the basal diet that contained 300, 600, 1,200 and 2,400 ICU of vitamin $D_3$ per kg. Each diet was offered ad libitum to one of the above five treatment groups. The egg production, egg weight, daily feed consumption and the feed intake per dozen eggs or kg egg mass of the birds fed diet without any supplemental vitamin $D_3$ was comparable with those of supplemental groups. Similarly, the level of vitamin in the diet did not have any effect on any of the above parameters. However, the specific gravity of eggs laid by the birds fed the diet without supplemental vitamin $D_3$ was comparable with either 600 or 2,400 ICU supplemental groups but significantly higher when compared to the 300 and 1,200 ICU groups. The egg -shell breaking strength was significantly lowered in the 600 ICU supplemental groups as compared to the strength of other dietary groups. The Haugh unit, egg shell weight, shell thickness, tibia breaking strength, bone ash and calcium content were not influenced by vitamin $D_3$ concentration in the diet. Serum Ca concentration was influenced by vitamin $D_3$ level in the diet. The serum Ca concentration of birds fed either control or the vitamin supplemented diet up to 1200 ICU/kg diet was comparable. However, increasing the concentration of vitamin $D_3$ to 2,400 ICU/kg diet significantly enhanced the concentration of Ca in the serum, which was significantly higher compared to other dietary groups. The serum concentration of P and protein, however, was not influenced by level of vitamin $D_3$ in the diet. Neither fertility nor hatchability was influenced by vitamin $D_3$ concentration in the diet. Feeding a vitamin $D_3$ deficient diet or supplementation of vitamin to hens did not have any influence on their progeny chicks. It can be concluded that dietary supplementation of vitamin $D_3$ may not be essential for optimum production, shell quality, hatchability, and juvenile performance of WL breeders during 72 to 88 weeks of age.

• The Journal of Engineering Research
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• v.3 no.1
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• pp.181-187
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• 1998

Hydroxyapatite was used as implant materials, because it has a good biocompatibility and is similar to human bone. However it is not expected to have a high strength as implant materials because of a low fracture strength after sintering of HAp. Alumina ($\alpha$-alumina) shows a stable chemical properties and high strength in physiological environments. Thus it was tried to use a HAp coatings on Alumina substrate as implant materials. In this study, HAp was coated on Alumina substrate by lon Beam Assisted Deposition(IBAD). Then Ag was impregnated on HAp coating layer, which showed antimicrobial effects. To carry out the ion exchange of $Ag^+$ with $Ca^{2+}$ in HAp on the surface, HAp coated alumina substrate was immersed in 20ppm, 100ppm $AgNO_3$ solution at room temperature for 48 hours. Antimicrobial test was studied by using bacteria, which normally caused periprosthetic infections. The follwing bacteria was used in antimicrobial test. Escherichia coli, Pseudomonas aeruginosa (gram negative) and staphylococcus epidermidis (gram positive). Ag impregnated HAp shows very good antimicrobial effects against these bacteria. The surface structure of sample, which was treated in $AgNO_3$ solution was studied by SEM, XRD. Ag release curve was studied in Simulated Body Fluid (SBF) solution.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.227-234
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• 2014

Purpose: The aim of this research was to develop and evaluate natural hydroxyapatite (HA) ceramics produced from the heat treatment of pig bones. Methods: The properties of natural HA ceramics produced from pig bones were assessed in two parts. Firstly, the raw materials were characterized. A temperature of $1,200^{\circ}C$ was chosen as the calcination temperature. Fine bone powders (BPs) were produced via calcinations and a milling process. Sintered BPs were then characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and a 2-year in vitro degradability test. Secondly, an indirect cytotoxicity test was conducted on human osteoblast-like cells, MG63, treated with the BPs. Results: The average particle size of the BPs was $20{\pm}5{\mu}m$. FE-SEM showed a non-uniform distribution of the particle size. The phase obtained from XRD analysis confirmed the structure of HA. Elemental analysis using XRF detected phosphorus (P) and calcium (Ca) with the Ca/P ratio of 1.6. Functional groups examined by FTIR detected phosphate ($PO{_4}^{3-}$), hydroxyl ($OH^-$), and carbonate ($CO{_3}^{2-}$). The EDX, XRF, and FTIR analysis of BPs indicated the absence of organic compounds, which were completely removed after annealing at $1,200^{\circ}C$. The BPs were mostly stable in a simulated body fluid (SBF) solution for 2 years. An indirect cytotoxicity test on natural HA ceramics showed no threat to the cells. Conclusions: In conclusion, the sintering temperature of $1,200^{\circ}C$ affected the microstructure, phase, and biological characteristics of natural HA ceramics consisting of calcium phosphate. The Ca-P-based natural ceramics are bioactive materials with good biocompatibility; our results indicate that the prepared HA ceramics have great potential for agricultural and biological applications.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.155-164
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• 1994

치조골흡수는 만성치주질환의 전형적인 증상이다. 골흡수에 작용하는 여러 요인들 중에서도, 특히 최근에 들어서 몇몇 cytokine들에 대한 관심이 높아지고 있는데, interleukin-1(IL-1), tumor necrosis factor(TNF) 및 interleukin-6(IL-6) 등이 치주질환의 진행과정에서 중요한 치조골흡수요인으로 제안되고 있다. 본 연구의 목적은 신생쥐의 골조직 배양실험을 통해서 recombinant human $interleukin-1{\beta}$ ($rHuIL-1{\beta}$), recombinant human tumor necrosis $factor-{\alpha}$($rHuTNF-{\alpha}$) 및 recombinant human interleukin-6(rHuIL-6) 의 골흡수 유도효과를 알아보고, cyclooxygenase 억제제인 indomethacin과 recombinant murine $interferon-{\gamma}$($rMurIFN-{\gamma}$)가 이들 cytokine의 골흡수 유도능력에 미치는 영향을 알아봄으로써 이들 cytokine의 작용기구에 대해서 알아보고자 하는데 있다. 생후 1-2일된 쥐에게 $1{\mu}Ci^{45}CaCl_2$를 피하주사하고 4일 후에 쥐를 희생시켜 $^{45}Ca$ 로 표지된 두개골을 얻어 24시간 전배양 후, 각 cytokine ($rHuIL-1{\beta}$, $rHuTNF-{\alpha}$ 및 rHuIL-6)과 cytokine 및 첨가약제 (indomethacin 및 $rMurIFN-{\gamma}$)가 함유된 배지로 교환하여 48시간 배양한다. 골흡수 유도효과는 두개골에서 48시간의 배양 중 유리되는 $^{45}Ca$의 방사능 정도로 평가하였다. 본 연구를 통해 다음과 같은 결과를 얻었다. 1. $rHuIL-1{\beta}$ ($10^{-12}-10^{-9}M$) 및 $rHuTNF-{\alpha}$ ($10^{-10}-10^{-8}M$)는 농도변화에 따르는 골흡수 유도효과를 보였으나 , rHuIL-6 ($10^{-10}-10^{-8}M$)는 유의할 만한 효과를 보이지 않았다. 2. Indomethacin ($10^{-6}M$)은 $rHuIL-1{\beta}$ 및 $rHuTNF-{\alpha}$의 골흡수 유도작용에 유의할 만한 억제효과를 나타내지 않았다. 3. $rMurIFN-{\gamma}$ (1000 U/ml) 은 $rHuIL-1{\beta}$ 및 $rHuTNF-{\alpha}$의 골흡수 유도작용에 유의한 억제효과를 나타내었다. 본연구를 통해 치주질환 환자의 치주조직에서 검출되는 $IL-1{\beta}$ 및 $TNF-{\alpha}$가 치조골 흡수에 중요한 역할을 할 것으로 생각된다.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.105-112
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• 2014

Purpose: The aim of present investigation was to find out the influence of several times iatrogenic mobilization in the initial stage of implant installation on bone-implant osteointegration. Materials and methods: The experimental implants (3.75 mm in diameter, 8.0 mm in length) were made of commercially pure (Grade IV) titanium, and were treated with RBM ($MegaGen^{(R)}$: Ca-P) on lower 4.0 mm part. Only lower part of implant was inserted to bone and the implants were nonsubmerged. The 130 implants (two in each tibia) were inserted into the monocortical tibias of 33 rabbits which each weighed more than 3.5 kg (Female, New Zealand White). According to the removal torque interval, the groups were divided into 13 groups, group I (1 day), group II (1 day + 2 days), group III (1 day + 2 days + 3 days), group IV (1 day + 2 days + 3 days + 4 days), group V (2 days), group VI (2 days + 4 days), group VII (2 days + 4 days + 6 days), group VIII (2 days + 4 days + 6 days + 8 days), group IX (4 days), group X (4 days + 7 days), group XI (4 days + 7 days + 10 days), group XII (4 days + 7 days + 10 days + 14 days) and control group. In the control group, the removal torque was measured at 8 weeks with a digital torque gauge (Mark-10, USA). In the experimental groups, the removal torque was given once, twice, three times or four times by experiment design before the final removal torque and the value was measured each time. The implants were then screwed back to their original positions. All the experimental groups were given a final healing time of 8 weeks after placement, in which values were compared with the control groups and the 1st, 2nd, 3rd or 4th removal torque values in each experimental group. Results: In comparison of the final removal torque tests among experimental groups, the removal torque value of experimental groups except group XII were not statistically different that of control group. And the values of group I and II were significantly higher than the values of group VI, VIII, X, XI, and XII. In addition, the values of group III, IV, and V were significantly higher than group XI and XII. In comparison of the removal torque in the each experimental group, the final removal torque were significantly higher in all groups except group VIII, X, XI, and XII. Conclusion: If sufficient healing time was allowed, a few mobilization of fixture at the very early stage after the implant placement in the rabbits didn't interrupt the final bone to implant osseointegration.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.197-206
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• 1997

Purpose : Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer Process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. Materials and Methods : The reaction mixture for the PLD assay contained $0.1\;\muCi\;1,2-di[1-^{14}C]palmitoyl$ phosphatidylcholine 0.5mM phosphatidylcholine, 5mM sodium oleate, $0.2\%$ taurodeoxycholate, 50mM HEPES buffer(pH 6.5), 10mM $CaCl_2$, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cmx loom and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy. Results : Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward $\gamma-rar$ with more than two times amplification in their activities In contrast, the PLD activity of bone marrow appears to be reduced to nearly $30\%$. Irradiation effect was hardly detected in liver which showed the lowest PLD activity. Conclusion : The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation s1ron91y indicates that the PLD is closely related to the physiological function of these organs, Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell Proliferation to cell death on these organs.