• 동굴
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• 제8호
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• pp.11-18
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• 1998

The mineral hydroxyapatite is very common species in secondary phosphates originating from guanos(HILL et at., 1997). Several mineralogical analyses of spelean hydroxyapatite exist(e.g., KASHIMA, 1968, 1979 ; MAKI et at., 1977 ; SUH et at., 1978 ; WANG, 1982 a, b), whereas detailedeochemical composition of secondary hydroxy apatites has not been reported in Japan.(omitted)

• 대한화학회지
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• 제13권1호
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• pp.62-67
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• 1969

The adaptabilities of various nitrohumates (-K, -Na and $-NH_4$ salt) as a soil conditioner and a raw material for soluble phosphatic fertilizer were studied. 1. Nitrohumates (especially $-NH_4$ salt) protect the soil from fissures and control the phosphoric acid adsorptive functions of soils considerably. 2. Most effective nitrohumic acids as a soil conditioner were prepared with 15% $HNO_3$ solution composed of five times of original humic acids (by weight) at $80^{\circ}C$ for 2 hrs under continuous stirring. 3. When 50% (by weight) of $NH_4$-nitrohumate were added to apatites in water and boiled for 2 hrs, maximum 26% of $P_2O_5$(apatite contains 37% of $P_2O_5$) were changed into water soluble forms.

• 한국재료학회지
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• 제15권11호
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• pp.690-696
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• 2005

The ultrastructure ore of a nanostructured apatite film nucleated from solution was studied to gain insights into that of bone minerals which is the most important constituent to sustain the strength of bones. Needle-shaped apatite crystal plates with a bimodal size distribution $(\~100\;to\;\~1000 nm)$ were randomly distributed and they were found to grow parallel to the c-axis ([002]), driven by the reduction of surface energy. Between these randomly distributed needle-shaped apatite crystals which are parallel to the film, apatite crystals (20-40nm) with the normal of the grains quasi-perpendicular to the c-axis were observed. These observations suggest that the apatite film is the interwoven structure of apatite crystals with the c-axis parallel and quasi-perpendicular to the fan. In some regions, amorphous calcium phosphate, which is a precursor of apatite, was also observed. In the amorphous phase, small crystalline particle with the size of 2-3 nm were observed. These particles were quite similar, in size and shape, to those observed in the femoral trabecular bone, suggesting the nucleation of apatites by a biomimetic process in vitro is similar to that in vivo.

• 자원환경지질
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• 제28권3호
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• pp.231-241
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• 1995

It is well known that hydroxyapatite [$Ca_{10}(PO_4)_6(OH)_2$] have an exchangeability for various heavy metal ions in aqueous solution. To evalute the feasibility of employing the synthetic hydroxyapatites as an eliminatable exchanger for environmentally noxious caions in waste water, the adsorption properties, the removal capacities and the selectivity of the apatites for various cations were investigated in more detailed. The heavy metal cations have been exchanged in calcium part of hydroxyapatite. The order of the degree of amount exchanged of the investigated cations is $Pb^{2+}>Cd^{2+}>Zn^{2+}>Ba^{2+}$. The molar ratios between released $Cd^{2+}$ ions and remeved divalent metal cations in the reacted solution with hydroxyapatite are roughly close to an integer 1.0, suggesting that an ion-exchange reaction could have played a major role in the removal of heavy metals rather then an adsorption effect. The exchangeability of the hydroxyapatite powder of Ca/P molar ratio 1.67, which have specipic surface area of $104.5m^2g^{-1}$, appeared to be better then $237.6{\mu}g$ per g for $Pb^{2+}$ ions. The removal capacity of the heavy metal ions varies directly as particle size of hydroxyapatites. All evidences obtained indicate that the synthesized hydroxyapatite powders by precipitation reaction method can be employed as an effective cation exchanger for eliminating noxious ions in waste water even in some improvemental.

• 한국결정성장학회지
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• 제22권6호
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• pp.279-285
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• 2012

BCP, Mg-BCP, Si-BCP 분말을 공침법(co-precipitation process)을 이용하여 합성하였다. 제조된 분말을 X-선 회절 분석(XRD), 적외선분광분석(FTIR)을 이용하여 특성을 분석하였다. Ca/P 몰 비율이 1.602인 칼슘 결손 아파타이트 공침물을 제조하여 $1000^{\circ}C$ 열처리 과정을 통하여 HAp와 ${\beta}$-TCP 상이 혼재된 BCP, Mg-BCP, Si-BCP을 합성할 수 있었다. 제조된 분말의 생체활성 거동을 평가하기 위하여 Hanks' Balanced Salt Solution(HBSS)에 침적시켜 시간에 따라 형상의 변화 및 결정상을 분석한 결과, BCP 분말에 비하여 금속 이온이 치환된 BCP 분말에서 빠른 생체활성을 관찰할 수 있었다. MTT assay를 통한 세포 성장률 평가에서모든 분말에서 시간 경과에 따라 독성을 나타내지 않았으며, 세포의 활성이 증가하였다.

• 한국재료학회지
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• 제19권7호
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• pp.362-368
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• 2009

Ti scaffolds with a three-dimensional porous structure were successfully fabricated using powder metallurgy and modified rapid prototyping (RP) process. The fabricated Ti scaffolds showed a highly porous structure with interconnected pores. The porosity and pore size of the scaffolds were in the range of 66$\sim$72% and $300\sim400\;\mu$m, respectively. The sintering of the fabricated scaffolds under the vacuum caused the Ti particles to bond to each other. The strength of the scaffolds depended on the layering patterns. The compressive strength of the scaffolds ranged from 15 MPa to 52 MPa according to the scaffolds' architecture. The alkali treatment of the fabricated scaffolds in an aqueous NaOH solution was shown to be effective in improving the bioactivity. The surface of the alkali-treated Ti scaffolds had a nano-sized fibre-like structure. The modified surface showed a good apatite forming ability. The apatite was formed on the surface of the alkali treated Ti scaffolds within 1 day. The thickness of the apatite increased when the soaking time in a simulated body fluid (SBF) solution increased. It is expected that the surface modification of Ti scaffolds by alkali treatment could be effective in forming apatites in vivo and can subsequently enhance bone formation.

• 대한금속재료학회지
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• 제48권6호
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• pp.575-580
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• 2010

Effects of the surface modification on the deposition behaviors of apatite crystals in Zr-1Nb plates were studied. Zr-1Nb alloy plates were polished with abrasive papers to have different roughness and some of them were treated in NaOH or coated with collagen before deposition of apatites in the simulated body fluid (SBF). The weight gain due to the deposition of apatite crystals increased as the surface roughness increased in Zr-1Nb. The size of granular apatite crystals were found to be smaller in Zr-1Nb roughened by $162{\mu}m$ abrasive paper than in Zr-1Nb roughened by $8.4{\mu}m$ paper, suggesting the nucleation rate increased with increase of surface roughness. After, 10 days immersion in a SBF, NaOH-treated Zr-1Nb was completely coated with apatite with the deposited apatite weight comparable to that in Ti-6Al-4V. The deposition rate of Zr-1Nb was not appreciably influenced by NaOH treatment unlike the significant influence of NaOHtreatment on the deposition rate of apatite in Ti-6Al-4V. One significant observation in this study is an appreciable increase of the apatite deposition rate after collagen coating both on Zr-1Nb and Ti-6Al-4V plate, which may be caused by the interaction between collagen and $Ca^{+2}$ ions.

• Journal of Periodontal and Implant Science
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• 제39권sup2호
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• pp.223-230
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• 2009

Purpose: Synthetic bone products such as biphasic calcium phosphate (BCP) are mixtures of hydroxyapatite (HA) and ${\beta}$-tricalcium phosphate (${\beta}$- TCP). In periodontal therapies and implant treatments, BCP provides to be a good bone reconstructive material since it has a similar chemical composition to biological bone apatites. The purpose of this study was to compare bone regeneration capacity of two commercially available BCP. Methods: Calvarial defects were prepared in sixteen 9-20 months old New Zealand White male rabbits. BCP with HA and ${\beta}$- TCP (70:30) and BCP with Silicon-substituted hydroxyapatite (Si-HA) and ${\beta}$-TCP (60:40) particles were filled in each defect. Control defects were filled with only blood clots. Animals were sacrificed at 4 and 8 week postoperatively. Histomorphometric analysis was performed. Results: BCP with HAand ${\beta}$- TCP 8 weeks group and BCP with Si-HA and ${\beta}$- TCP 4 and 8 weeks groups showed statistically significant in crease (P <0.05) in augmented area than control group. Newly formed bone area after 4 and 8 weeks was similar among all the groups. Residual materials were slightly more evident in BCP with HA and ${\beta}$- TCP 8 weeks group. Conclusions: Based on histological results, BCP with HA and ${\beta}$- TCP and BCP with Si-HA and ${\beta}$- TCP appears to demonstrate acceptable space maintaining capacity and elicit significant new bone formation when compared to natural bone healing in 4 and 8 week periods.

• Journal of Periodontal and Implant Science
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• 제49권6호
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• pp.382-396
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• 2019

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO₃Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO₃Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO₃Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO₃Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO₃Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO₃Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.

• 한국결정성장학회지
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• 제20권5호
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• pp.237-242
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• 2010

Mg-BCP(Mg Substituted BCP)를 제조하기 위하여 $Ca(NO_3)_2{\cdot}4H_2O$(Katayama chemical, Japan)과 $(NH_4)_2{\cdot}HPO_4$ (Junsei chemical, Japan), $Mg(NO_3)_2{\cdot}6H_2O$(Junsei chemical, Japan)를 출발물질로 공침법(co-precipitation process)을 이용하여 합성하였다. 제조된 분말의 마그네슘의 첨가에 따른 분말의 분광학적 특성은 FT-IR(MAGNA-IR 560, Nicolet)을 통하여 분석하였으며, SEM(S-4200, Hitachi)을 통하여 미세구조를 분석하였다. XRD 회절피크의 면적적분강도를 Integral Analysis (Rigaku, Japan)를 이용하여 HAp와 ${\beta}$-TCP의 비율을 확인하였다. 1.0 wt% 마그네슘이 첨가된 BCP 샘플의 경우 Hank's solution에서의 2주 침적 후 표면에 침상의 HAp로 추정되는 결정이 성장하였다. 이러한 미세구조의 변화는 생활성을 가지는 마그네슘의 첨가가 BCP 조직 내에서 표면의 활성을 증가시켜 결정의 성장을 촉진시킨 것으로 판단된다.