• 대한화학회지
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• 제52권1호
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• pp.57-65
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• 2008

나노 또는 마이크로 크기를 가지는 구형의 약물 전달체이다. 그러나 일반적인 리포솜은 혈류 순환시 혈장 단백질과의 흡착이 일어나 안정성이 떨어지고, 세망내피계의 대식세포에 의해 옵소닌작용이 일어나 혈중에서 쉽게 소실되는 단점이 있다. 이에 본 연구에서는 모델단백질로 소혈청 알부민(BSA)을 사용하였고, BSA의 등전점보다 높은 pH를 나타내는 수용액에 용해하여 BSA가 음이온성을 갖도록 제조하였으며 이를 양이온성 리포솜 표면에 정전기적 인력에 의해 결합시켰다. 그리고 리포솜 표면에 코팅된 알부민을 60oC 이상의 온도에서 변성시켜 알부민이 코팅된 리포솜을 제조하였다. 대조 리포솜과 양이온성 리포솜의 입자크기는 104±1nm를 나타내었고, 변성된 알부민이 결합된 리포솜은 109±1nm의 입자크기를 나타내었다. 모델약물로서는 독소루비신(doxorubicin, DOX)을 사용하였고, 이온구배에 의한 리모트 로딩 방법을 사용하여 리포솜 내부에 DOX를 봉입시켰다. 혈장 내에서 리포솜의 안정성을 평가한 결과, 알부민이 결합된 리포솜은 입자크기의 변화가 관찰되지 않았고, 대조 리포솜과 양이온 리포솜에 비해 단백질 흡착이 억제되어 변성된 알부민으로 코팅된 리포솜은 혈류 내에서 장기 순환이 가능한 약물전달체로서 유용할 것이라 사료된다.

• E2M - 전기 전자와 첨단 소재
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• 제10권2호
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• pp.141-149
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• 1997

L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.199-199
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• 2016

Commercially pure titanium (cp-Ti) and Ti alloys (typically Ti-6Al-4V) display excellent corrosion resistance and biocompatibility. Although the chemical composition and topography are considered important, the mechanical properties of the material and the loading conditions in the host have, conventionally. Ti and its alloys are not bioactive. Therefore, they do not chemically bond to the bone, whereas they physically bond with bone tissue. The electrochemical deposition process provides an effective surface for biocompatibility because large surface area can be served to cell proliferation. Electrochemical deposition method is an attractive technique for the deposition of hydroxyapatite (HAp). However, the adhesions of these coatings to the Ti surface needs to be improved for clinical used. Plasma electrolyte oxidation (PEO) enables control in the chemical com position, porous structure, and thickness of the $TiO_2$ layer on Ti surface. In addition, previous studies h ave concluded that the presence of $Ca^{+2}$ and ${PO_4}^{3-}$ ion coating on porous $TiO_2$ surface induced adhesion strength between HAp and Ti surface during electrochemical deposition. Silicon (Si) in particular has been found to be essential for normal bone and cartilage growth and development. Zinc (Zn) plays very important roles in bone formation and immune system regulation, and is also the most abundant trace element in bone. The objective of this work was to study electrochemical characteristcs of Zn and Si coating on Ti-6Al-4V by PEO treatment. The coating process involves two steps: 1) formation of porous $TiO_2$ on Ti-6Al-4V at high potential. A pulsed DC power supply was employed. 2) Electrochemical tests were carried out using potentiodynamic and AC impedance methoeds. The morphology, the chemical composition, and the micro-structure an alysis of the sample were examined using FE-SEM, EDS, and XRD. The enhancements of the HAp forming ability arise from $Si/Zn-TiO_2$ surface, which has formed the reduction of the Si/Zn ions. The promising results successfully demonstrate the immense potential of $Si/Zn-TiO_2$ coatings in dental and biomaterials applications.

• 미생물학회지
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• 제39권4호
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• pp.242-247
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• 2003

Murine encephalomyocarditis virus (EMCV)는 혈장유래의약품의 바이러스 안전성 검증을 위해 hepatitis A virus (HAV)의 모델 바이러스로 사용되어왔다. 근래에 혈액응고인자제제에 의한 HAV 감염사례가 보고되면서 혈장유래의약품의 HAV 안전성 검증에 대한 국제적인 규제가 강화되어가고 있다. 본 연구에서는 HAV와 EMCV의 바이러스 불활화 공정에 대한 민감도를 평가하여, 혈장유래의약품 제조공정에서 HAV 불활화 공정의 검증법을 표준화하고자 하였다. HAV와 EMCV의 바이러스 불활화 공정에 대한 민감도를 평가한 결과 HAV가 60$^{\circ}C$ 열처리, low pH 처리(pH 3.9), 0.1 M NaOH 처리, 동결건조 공정 모두에서 EMCV보다 더 저항성이 큰 것을 확인할 수 있었다. EMCV는 특히 열처리와 0.1 NaOH 처리에 민감하게 불활화 되었지만, HAV는 큰 저항성을 나타내었다. 열처리의 경우 2시간 안에 EMCV는 검출한계 이하로 감소하였지만, HAV는 5시간 후에 검출한계 이하로 감소하였다. 0.1 M NaOH 처리시 EMCV는 15분 안에 검출한계 이하로 감소하였지만, HAV는 120분 정도의 처리에도 감염성 바이러스가 검출되었다. pH 3.9에서 25$^{\circ}C$로 14일 동안 항온하였을 때 HAV와 EMCV의 log 감소인수는 각각 1.63, 3.84이었다. 또한 혈액응고 8인자 제조공정의 동결건조 과정에서 HAV와 EMCV의 log 감소인수는 각각 1.21, 4.57이었다. 이와 같은 결과는 혈장유래의약품 제조공정의 HAV 불활화 또는 제거 검증시 모델 바이러스로 사용된 EMCV의 검증 결과를 해석함에 있어 보다 신중함을 가져야 한다는 것을 보여준다. 또한 보다 정확한 HAV검증 결과를 얻고자 한다면 모델 바이러스인 EMCV 보다 HAV를 사용하는 것이 보다 더 타당하다고 사료된다.

• 한국진공학회지
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• 제21권6호
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• pp.328-332
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• 2012

Ag (silver)의 일함수는 T-OLED (Top Emission Organic Light Emitting Diode)의 전극소자로 사용하기에는 다소 낮다는 단점이 있다(~4.3 eV). 이러한 단점을 해결하기 위한 대안으로 Ag 박막의 표면을 플라즈마, UV, 열처리를 통하여 일함수를 높이는 연구가 진행되어 왔다(~5.0 eV). 하지만 현재의 대부분 연구는 후 처리된 박막의 일함수에 초점을 맞춰 연구가 진행되어, 박막의 mechanical property에 대한 연구는 매우 부족하며 이는 T-OLED의 효율과 수명 등의 연구에 매우 중요하다. 본 논문에서는 Ag와 $AgO_x$ 박막의 mechanical property에 초점을 맞춰 분석을 실시하였다. Ag는 유리기판 위에 rf-magnetron sputter를 이용하여 100 W의 power에서 150 nm 두께로 증착되었다. 증착된 박막은 UV 램프를 이용하여 다양한 시간동안 UV 처리되었다(0~9분). 본 논문에서는 처리된 박막의 면저항을 측정하고 nano indenter, Scanning Probe Microscopy의 Atomic Force Microscopy mode를 이용하여 mechanical property를 분석하였다. 실험 결과 UV 처리 시간이 3분을 넘어가는 시편과 3분 이내의 시편은 면저항값 및 경도 값에 큰 차이가 있었다. 이러한 결과는 Ag 박막의 후처리에 따른 Ag 물질의 산화 및 결합상태에 따라 박막 내에 존재하는 stress의 영향으로 예상되어진다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.375.2-375.2
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• 2016

그래핀(Graphene)은 원자 한 층 두께의 얇은 특성에 기인하여 우수한 투과도(~97.3%)를 나타내며, 높은 전자 이동도($200,000cm^2V^{-1}s^{-1}$)로 인하여 전기 전도도가 우수한 2차원 전자소재이다. 또한 유연하고 우수한 기계적 물성을 가지고 있어 실제로 다양한 소자에서 활용되고 있다. 그래핀을 이용하여 다양한 소자로 응용하기 위한 과정 중 하나인 포토리소그래피 공정(Photolithography process)은 원하는 패턴을 만들기 위해 제작하고자 하는 기판 위에 포토레지스트(Photoresist)를 코팅하는 과정을 거치게 된다. 하지만 이러한 과정은 소자 제작에 있어서 포토레지스트 잔여물을 남기게 된다. 그래핀 위에 남은 포토레지스트 잔여물은 그래핀의 우수한 전기적 특성을 저하시켜 소자특성에 불이익을 주게 된다. 본 연구에서는 수소 플라즈마를 이용하여 그래핀 위에 남은 중합체(Polymer) 잔여물을 제거한다. 사용한 그래핀은 화학 기상 증착법(Chemical vapor deposition)을 이용하여 성장시켰으며, PMMA(Poly(methyl methacrylate))를 이용하여 이산화규소(silicon dioxide) 기판에 전사하였다. 그래핀의 손상 없이 중합체 잔여물을 제거하기 위해 플라즈마 처리시간을 15초부터 1분까지 늘려가며 연구를 진행하였으며, 플라즈마 처리 시간에 따른 중합체 잔여물의 제거 정도와 그래핀의 보존 여부를 확인하기 위해 라만 분광법(Raman spectroscopy)과 원자간력현미경(Atomic force microscopy)을 사용하였다. 본 연구 결과를 통해 간단한 플라즈마 처리로 보다 나은 특성의 그래핀 소자를 얻게 됨으로써, 향상된 특성을 가진 그래핀 소자로 산업적 응용 가능성을 높일 수 있을 것이라 생각된다.

• Journal of Nutrition and Health
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• 제32권4호
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• pp.337-352
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• 1999

The effects of dried leaf powders and ethanol extract of persimmon, green tea and pine needle on lipid metabolism, lipid peroxidation and antioxidative activity were investigated in rats. Forty-nine male Spargue-Dawley rats weighing 107.8$\pm$1.8g were blocked into seven groups according to body weight. Rats were raised for four weeks with diets containing either 5%(w/w) dried leaf powders of one of three different Korea traditional teas, persimmon(Diospyros kaki Thunb), green tea(Camellia Sinensis O.Ktzc)or pine needle(pinus Koreansis Sieb. Et Zucc), or ethanol from equal amounts of each dried tea powder. Food intake, weight gain, food efficiency ratio, and weights of liver, kidney and epididymal fat were significantly higher in the green-tea-powder group, and significantly lower in the pine-needle-powder and pine-needle-extract groups. Persimmon-leaf powder was found to decrease plasma total lipid, triglyceride and cholesterol concentration by increasing fecal total lipid triglyceride and cholesterol excretions. Liver cholesterol concentration was significantly lower in the green-tea and pine-needle-extract groups. Red-blood-cell superoxide dismutase(SOD) and glutathione peroxidase(GSH-px) activities were significantly increased in rats fed green-tea extract. Liver SOD activity was increased in rats fed pine-needle powder or extract, and liver GSH-px activity was increased in rats fed greentea powder. Plasma and liver thiobarbituric acid reactive substance(TBARS) concentration were both decreased in rats fed dried leaf posers or extracts of persimmon or green tea. It is believed that high vitamin E levels in persimmon leaf, and high flavonoid, beta-carotene and vitamin C levels in green tea effectively inhibited lipid peroxidation. In conclusion, persimmon and green tea leaves were effective in lowering lipid levels and inhibiting lipid peroxidation in animal tissue, while pine needles were effective and lowering body weight gain. From these results, persimmon and green tea leaves can be recommended in the treatment and prevention of chronic discorders such as cardiovascular disease, cancer and aging. As ethanol extracts from these teas were also effecitive in lowering tissue lipid levels and inhibiting lipid peroxidation, we recommend the use of discarded tea grounds for this.

• 한방재활의학과학회지
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• 제30권2호
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• pp.19-35
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• 2020

Objectives The aim of this study is to evaluate the fracture healing effect of Jinmu-tang (JM) on femur fractured rats. Methods Rats were randomly divided into 5 groups (normal, control, positive control, JM extract with low concentration and JM extract with high concentration). All group except normal group went through both femur fracture. Normal and control group received no treatment at all. Positive control group were medicated with tramadol (20 mg/kg) once a day for 14 days. Experimental group was orally medicated with JM extract (10 mg/kg for low concentration, 50 mg/kg for high concentration) once a day for 14 days. In order to investigate fracture healing process, plasma and serum were obtained. Also, micro-computed tomography was conducted to see the frature site visually. Immunohistochemistry for transforming growth factor-β1, Ki67, alkaline phosphatase, runt-related transcription factor 2, receptor activator of nuclear factor kappa-β, tartrate resistant acid phosphatase was conducted to observe bone healing progress after 14 days since fracture occured. Aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen and creatinine levels were measured in plasma, for hepatotoxicity and nephrotoxicity of JM extract. Osteocalcin was measured to observe activity of osteoblast. Results Through Micro-CT, more fracture healing was observed on both experimental group than control and positive control group. Through Hematoxylin & Eosin and safranin O staining showed bone cell proliferation and bone formation in the experimental group. RANK was significantly increased in the experimental groups. JM with high concentration showed statistically significant of TGF-β and Osteocalcin. NO, TRAP and ALP were not significantly changed. Liver toxicity was not significantly observed. Creatinine significantly increased in both experimental groups after 28 days. Conclusions As described above, JM extract showed anti-inflammatory effect, promoted fracture healing by stimulating the bone regeneration factor, and showed little hepatotoxicity and nephrotoxicity. In conclusion, JM extract can promote fracture healing and it can be used clinically to patients with fracture.

• 공업화학
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• 제9권2호
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• pp.165-171
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• 1998

$Y_2O_3$(99.9%)와 $BaCO_3$(99.9%) 및 CuO(99.9%)를 사용하여 $Y_1Ba_2Cu_3O_{7-x}$(123) 분말을 발화합성법에 의해 제조하였다. 발화전 용액을 여러 가지 pH로 변화시켜 제조하였으며, 이 분말을 성형하여 열처리 온도와 시간 변화에 따른 상형성과 반응특성을 조사하였다. 시료의 조성과 조직의 특성은 ICP와 SEM을 이용하여 측정하였고, Y-Ba-Cu-O계의 상형성과 전화율을 결정하기 위해 X선 회절분석을 하였다. 발화합성법을 이용하여 pH 7(${\pm}0.3$)에서 제조된 123 분말이 순도와 균일성 및 반응특성에서 가장 좋은 결과를 보였다. pH 7(${\pm}0.3$)에서 제조된 분말을 이용한 123 상생성에 따른 활성화에너지(${\Delta}E_a$)는 191kJ/mol으로서 고상반응법의 230kJ/mol에 약 13% 정도 더 낮았다.

• 대한핵의학회지
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• 제38권2호
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• pp.152-160
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• 2004

Radioiodide uptake in thyroid follicular epithelial cells, mediated by a plasma membrane transporter, sodium iodide symporter (NIS), provides a first step mechanism for thyroid cancer detection by radioiodide injection and effective radioiodide treatment for patients with invasive, recurrent, and/or metastatic thyroid cancers after total thyroidectomy. NIS gene transfer to tumor cells may significantly and specifically enhance internal radioactive accumulation of tumors following radioiodide administration, and result in better tumor control. NIS gene transfers have been successfully performed in a variety of tumor animal models by either plasmid-mediated transfection or virus (adenovirus or retrovirus)-mediated gene delivery. These animal models include nude mice xenografted with human melanoma, glioma, breast cancer or prostate cancer, rats with subcutaneous thyroid tumor implantation, as well as the rat intracranial glioma model. In these animal models, non-invasive imaging of in vivo tumors by gamma camera scintigraphy after radioiodide or technetium injection has been performed successfully, suggesting that the NIS can serve as an imaging reporter gene for gene therapy trials. In addition, the tumor killing effects of I-131, ReO4-188 and At-211 after NIS gene transfer have been demonstrated in in vitro clonogenic assays and in vivo radioiodide therapy studies, suggesting that NIS gene can also serve as a therapeutic agent when combined with radioiodide injection. Better NIS-mediated imaging and tumor treatment by radioiodide requires a more efficient and specific system of gene delivery with better retention of radioiodide in tumor. Results thus far are, however, promising, and suggest that NIS gene transfer followed by radioiodide treatment will allow non-invasive in vivo imaging to assess the outcome of gene therapy and provide a therapeutic strategy for a variety of human diseases.