• 한국결정성장학회지
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• 제21권5호
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• pp.210-213
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• 2011

$P_2O_5$ 함량에 따른 $5Na_2O-36CaO-10TiO_2-xP_2O_5$으로 구성된 glass-ceramic을 다음과 같은 방법으로 제조하였다: 1) 1 N HCl 용액 내에서 $Ca_3(PO_4)_2$와 $NaTi_2(PO_4)_3$ 간의 $Ca_3(PO_4)_2$ 결정을 2일간 추출하여 제거함. 2) Ag($NO_3$) 용액에서 1일간 $Na^+$ 이온을 $Ag^+$ 이온으로 이온 교환시킴. Glass-ceramic의 합성 여부를 SEM 및 XRD를 이용하여 확인하였다. Staphylococus aureus를 이용한 박테리아 실험 결과 3시간 이후에는 완전하게 박테리아가 제거됨을 확인할 수 있었다.

• 한국재료학회지
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• 제24권12호
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• pp.671-676
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• 2014

It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel ($Ag-30CaO{\cdot}70SiO_2$ gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological $Ag-30CaO{\cdot}70SiO_2$ is tested. This was done to impart antimicrobial activity to the $30CaO{\cdot}70SiO_2$. Ag ion was added during sol-gel synthesis to replace the $H_2O$ added during the making of the $30CaO{\cdot}70SiO_2$ gel, which has silver solutions of various concentration. After the sol-gel process, 1N-$HNO_3$ solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-$SiO_2$ gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is $Ag-30CaO{\cdot}70SiO_2$ gel.

• 한국산학기술학회논문지
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• 제3권3호
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• pp.183-188
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• 2002

Antibacterial glass ceramics composed of $5Li_2O{\cdot}36CaO{\cdot}20TiO_2{\cdot}27P_2O_5$ were Prepared. After ion exchange in the $AgNO_3$solution, crystallization phases were $AgTi_2(PO_4)_3$, $LiTi_2(PO_4)_3$ and $Ca_3(PO_4)_2$. In case of ion exchange, the crystallization phases started to be transformed from $LiTi_2(PO_4)_3$ to $AgTi_2(PO_4)_3$in 0.5 mole $AgNO_3$ solution and the transformation was almost completed in 1.0 mole. ion exchange rate of glass-ceramics powder, considering ion exchange time, was more fast than that of bulk. The bacteriostatic effect of the glass-ceramics on Staphyloroccus aureus and Salmonella typhi bacteria was more excellent than that of glass when the crystallization phase was transformed from LTP to AgTP.

• 한국진공학회지
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• 제6권S1호
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• pp.27-33
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• 1997

Recently ion beam assistant deposition (IBAD) was successfully used to produce a dense ultra-adherent and pinhole-free hydroxyapatite (HAp) layer on alumina substrate. After that the HAp-coated alumina was immersed in 20ppm and 100ppm $AgNO_3$ solution at room temperature for 48 hours to carry out the ions exchange between $Ag^+\;and\;Ca^+$ in HAp. The obvious antimicrobial effect against E.Coli, P. Aeruginosa and S. Epidermidis was observed in the samples treated with 20ppm $AgNO_3$ Solution, In contrast to this the untreated samples did not show any bactericidal effect. Scanning electron microscope(SEM) study showed that Ag homogeneously distributed on the surface. X-ray diffraction (XRD) demonstrated that the surface structure in the samples without Ag was HAp whereas with Ag is HAp and AgCaP. It appears that silver ions exchange with calcium ions in HAp does not cause significant changes in the structure of HAp coatings.

• 대한두경부종양학회지
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• 제17권2호
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• pp.148-154
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• 2001

Objectives: This study was designed to investigate the significance of serum SCC antigen, CA 19-9, CA 125 level and DNA microsatellite alterations (MSA) as prognostic factors and indicators for recurrences in the pre-treatment and post-treatment state, respectively in head and neck cancer patients. Materials and Methods: 120 patients who received curative treatment for head and neck cancer from 1995 to 2000 were followed up successfully, and were analyzed retrospectively. Thirty healthy subjects served as normal controls. Serum SCC Ag levels were measured by microparticle enzyme immunoassay technique via IMX SCC assay, CA 19-9 levels were measured by CA 19-9 RIA test kit, and CA 125 levels were measured by CA 125 IRMA kit. MSA were identified after PCR amplification. Heterozygosity was considered lost if the ratio of one allele was significantly decreased (>50%) in serum DNA compared with normal DNA from lymphocytes. Results: Preoperative tumor markers were higher in cancer patients than control, but not significant. Postoperative SCC Ag levels were lower than preoperative levels. The SCC Ag levels were remained low in no evidence of disease (NED) group, but increased in locoregional recurrence and distant metastasis group. CA 19-9 and CA 125 levels showed no correlation between levels and recurrences and were not decreased significantly after primary tumor removal. MSA were detected in five out of 21 cases, and highly detected in distant metastasis group. Conclusion: SCC Ag seems to be a helpful serum tumor marker for early detection of recurrence and distant metastasis of head and neck cancer after curative treatment. But, CA 19-9 and CA 125 were not reliable markers for head and neck tumors. MSA were not statistically significant because of the small number of study group. However they may be helpful for screening serum molecular markers for early detection of distant metastasis of head and neck cancers.

• Journal of Pharmaceutical Investigation
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• 제31권2호
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• pp.101-106
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• 2001

Alginate-chitosan (anion-cationic polymeric complex) was prepared to control the release rate of silver sulfadiazine (AgSD). Na-alginate (2%) solution containing AgSD was gelled in $CaCl_2$ solution. The gel beads formed were immediately encapsulated with chitosan (CS). The gel matrix and membrane were then reinforced with chondroitin-6-sulfate (Ch6S). Release rate of AgSD from the gel matrix was investigated by placing alginate beads in the sac of cellulose membrane simmered in HEPES-buffer solution. The concentration of AgSD released was analyzed by UV at 264 nm. Incorporation capacity of AgSD in Ca-alginate gel was more than 90%. Alginate-Ch6S-CS could control the release rate of AgSD. The amount of AgSD release was dependent on the AgSD loading dose. Incorporation of tripolyphosphate (polyanionic crosslinker) onto the alginate-Ch6S-CS bead increased the release rate of AgSD. Collagen-coating had no influence on the AgSD release rate. Alginate-Ch6S-CS beads with a sufficiently high AgSD encapsulation were capable of controlling the release of the drug over 10 days. In summary, alginate-Ch6S-CS beads could be used as a sustained delivery for AgSD and provide local targeting with low silver toxicity and patient discomfort.

• 한국세라믹학회지
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• 제38권12호
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• pp.1104-1109
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• 2001

110K상의 산화물 고온초전도체를 B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/의 출발조성비로 고상반응법(solid-state reaction)에 의해 합성하였다. 이렇게 합성된 Bi계 110K상의 산화물 고온초전도 물질을 다시 분말 상태로 만든 후, Ag 금속분말을 10wt%, 30wt%, 50wt%의 각 비율로 혼합하였다. Ag 금속분말이 혼합된 시편들을 86$0^{\circ}C$~875$^{\circ}C$로 24시간 동안 최종 소결시켰다. 그후, 각 시편들에 대하여 x-선, $T_{c}$, SEM 등을 측정하여 Ag 혼합량에 대한 초전도특성 및 표면의 grain 크기변화 등에 대한 조사를 진행하였다. Ag 혼합량이 증가됨에 따라 Ag peak의 강도는 증가되었고, 시편 내 2223 상의 비율은 감소하고 2212상의 비율은 증가되었다.비율은 증가되었다.

• 대한본초학회지
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• 제37권3호
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• pp.9-19
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• 2022

Objectives : Angelicae Gigantis Radix (AG) is a plant of the Ranunculus family. AG have been reported to have various pharmacological effects on human health which include uterine growth promotion, anti-inflammatory, analgesic, and immune enhancement. However, research on dermatitis disease is insufficient. Therefore, we investigated the effects of AG on tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ) stimulated HaCaT cell. Methods : To investigate the effect of AG on HaCaT cell, HaCaT cells were pre-treated with AG for 1 hour and then stimulated with TNF-α/IFN-γ. After 24 hours, media and cells were harvested to analyze the inflammatory mediators. Concentration of human interleukin-1beta (IL-1β), monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), and TNF-α in the media were assessed by ELISA. mRNA expression of human thymus and activation-regulated chemokine (TARC), IL-6, and IL-8 were analyzed by RT-PCR. Additionally, the mechanisms of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway were investigated by Western blot. Results : The treatment of AG inhibited gene expression levels of IL-6, IL-8, and TARC and protein expression levels of IL-1β, MCP-1, and GM-CSF. Also, AG significantly reduced extracellular signal-regulated kinase (ERK) phosphorylation and NF-κB translocation in TNF-α/IFN-γ stimulated HaCaT cell. Conclusions : Taken together, these results demonstrate that AG can alleviate inflammatory diseases such as atopic dermatitis by regulating the expression of inflammatory cytokines. Also, it suggest that AG may a promising candidate drug for the treatment of inflammatory disease such as atopic dermatitis.

• Korean Chemical Engineering Research
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• 제60권2호
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• pp.175-183
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• 2022

자동차 시장의 확대에 따라 자동차 모터의 필수 소재로 희토류금속인 Nd에 대한 수요가 급증하고 있다. Nd를 제조하기 위하여 Nd₂O₃와 Ca계 합금의 열 환원반응에 관한 연구가 활발히 진행되어 왔다. 본 연구에서는 Nd₂O₃의 환원제로 사용되는 Ca계 합금인 Ca-Cu를 CaCl₂ 용융염에서 전기분해반응을 통해 제조하였다. 전기분해반응의 작업 전극과 상대전극으로는 Cu 와이어와 흑연을 각각 사용하였다. 기준전극은 AgCl:CaCl₂=1:99 mol%로 혼합한 혼합물에 Ag 와이어를 넣어 제작하였다. 순환전압 전류법 결과에 의하면 -1.8 V의 전위부터 작업전극의 표면에 Ca²⁺의 증착이 관찰되었으며, CaCl₂ 염의 온도가 증가할수록 Ca²⁺의 환원전위가 감소하였다. 시간대전류법 실험을 통해 계산된 Ca²⁺의 확산계수는 5.4(±6.8)×10^-6 cm²/s으로 나타났다. 또한, Cu 전극에 일정한 전위를 가해 Ca-Cu 액상합금을 제조하였으며 제조된 합금은 EDS line scan을 통해 인가 전위의 증가에 따라 Ca의 전기화학적 삽입이 증가함을 확인하였다. -2.0 V보다 음의 전위를 인가하여 제조한 Ca-Cu 합금의 조성비는 Ca:Cu=1:4임을 확인하였다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2002년도 춘계학술발표논문집
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• pp.74-76
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• 2002

항균성 및 원적외선 방사량이 높은 원적외선 방사 항균 글라스 및 글라스 세라믹스의 양산화를 위한 유리 용융에 있어 대량용융의 가능성을 확인할 수 있었으며, 열처리온도는 5Li₂Oㆍ36CaOㆍ20TiO₂ㆍ27P₂O/sub 5/와 1Ag₂Oㆍ4Li₂Oㆍ36CaOㆍ20TiO₂ㆍ27P₂O/sub 5/ 조성에서 최적핵형성온도가 620℃, 최적결정성장온도가 각각 78℃, 800℃였다. 원가절감을 위산 건식법과 습식법의 결정상분석의 결과 피크의 차이는 거의 없었다. 이온교환의 경우 5.0mol AgNO₃수용액에 담지한 시편에서는 많은 LTP 결정상이 AgTP 결정상으로 변환되기 시작하여 1.0omol 농도의 AgNO₃ 수용액에서는 결정상의 주피크가 AgTP 절정상으로 변이 되었다. 이 결과로 AgNO₃ 수음액 0.5mol 농도 이상의 이온교환시 항균특성에 있어서도 매우 유리하리라 예상되어진다.