• 대한화장품학회지
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• 제39권3호
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• pp.225-231
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• 2013

아스타잔틴을 포함하는 수중유형 형태의 나노에멀젼을 고압균질기를 이용하여 제조하였다. 이에 유화조건, 유화제 종류, 유화제 농도 그리고 아스타잔틴 농도에 따라 최적화를 되었다. 나노에멀젼의 안정성은 제타포텐셜, FF-SEM, 입도분석기, 색차계를 이용하여 측정하였다. 제조된 아스타잔틴 나노에멀젼의 입도는 160 ~ 190 nm로 균일하였으며 레시친에 의한 나노에멀젼 보다 glyceryl citrate/lactate/linoleate/oleate에 의한 나노에멀젼이 더욱 안정하고 균일한 입도분포를 가졌다. 아스타잔틴의 봉입도는 HPLC, FF-SEM을 이용하여 확인 하였으며, 제형 구성 후 보관조건에서의 안정도 및 제타 포텐셜 값도 -41의 우수한 결과를 나타내었다.

• 자원환경지질
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• 제33권1호
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• pp.19-30
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• 2000

The Sannae-Eonyang granitic rocks are a large fossil hydrothermal system containing the Sannae Mo-W fissure-vein type and the Eonyang amethyst deposits in the southeastern Kyongsang Basin. They evolved through similar stages showing the similarities in chemical and mineralogical compositions, fractionation trends and early magmatic fluids. Major, trace and rare earth element(REE) variations can be accounted for fractional crystallization combined with variable degrees of metasomatism. Based on the aqueous fluids exsolved directly from the crystallizing melt, the Sannae-Eonyang granitic rocks were emplaced at similar depth or pressure conditions. High temperature fluid interaction with the granitic rocks affects the elements such as K, Na, Rb, Ba, Sr, Eu, and heavy REE (HREE) mostly through feldspar re-equilibration. Although hydrothermal fluids produced partly positive Eu anomalies and HREE depletion in the granitic rocks at the Sannae Mo-W mine, the chemical concentrations defining fractionnation trends have survived the effects of alteration. Aqueous fluids exsolved from the crystallizing melt appears to be widespread, whereas fluids of moderate to low salinity and low-density with relatively high homogenization temperatures and $Co_2$-rich fluids appear to be mainly restricted and responsible for Mo-W and amethyst mineralization, respectively. Hydrothermal system of the Sannae-Eonyang granitic rocks represents repeated fluid events; from exsolution of aqueous fluids from the crystallizing melt, through fluid immiscibility and meteoric convection to later mineralization.

• 한국분말재료학회지
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• 제17권6호
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• pp.482-488
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• 2010

In this study, $FeSi_2$ as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below $1200^{\circ}C$ for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering ($1200^{\circ}C$, 12 h). In order to precipitate ${\beta}-FeSi_2$, heat treatment was performed at $850^{\circ}C$ with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase ${\beta}-FeSi_2$ was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.

• 자원환경지질
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• 제6권4호
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• pp.195-200
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• 1973

Temperature environments of the formation of fluorite deposits in the Wolaksan area and the Cheonil Mine, Chungcheongbuk-Do are presented and interpreted in brief. These deposits occur more or less near the contact zone between the Paleozoic limestone formations and the Cretaceous biotite granites as a number of hydrothermal veins or replacement deposits. The homogenization temperatures of fluorite crystals from the Wolaksan area fall within the narrow range of $149{\sim}167^{\circ}C$, of which lower limit is quite high, while those of the Cheonil Mine show wide range of $126{\sim}177^{\circ}C$, which indicates much lower mean temperature of formation. If the possible correction for pressure, which may not exceed $+30^{\circ}C$ as the depth of the deposits was 1.5km, were applied, the possible highest value of the true formation temperatures of fluorites in both area might be reached to around $200^{\circ}C$ that means these deposits were formed as a series of early products of the epithermal stage of hydrothermal processes.

• Journal of Pharmaceutical Investigation
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• 제41권5호
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• pp.295-300
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• 2011

Paclitaxel is a well known anticancer agent and has been a pharmaceutical challenge because of its extremely poor water-solubility and susceptibility to the p-glycoprotein (p-gp)-mediated efflux in multi-drug resistant (MDR) cancer cells. Tributyrin (TB), a triglyceride with relatively short fatty acid chains, was chosen as solubilizing vehicle for paclitaxel based on the solubility study (26.6 mg/mL). Tributyrin (10%) o/w emulsion containing paclitaxel (5%), egg phosphatidylcholine (5%) and pegylated phospholipid (0.5%) was prepared by high pressure homogenization to obtain submicron-sized emulsion. The mean particle size of the resultant TB emulsion was 395.5 nm. Paclitaxel in TB emulsion showed higher anticancer activity against human breast cancer cell line, MCF-7, than free form delivered in DMSO solution. On the other hand, its anticancer activity was significantly reduced in MCF-7/ADR, a MDR variant cancer cell line of MCF-7, and recovered by the presence of verapamil, suggesting of the susceptibility to the p-gp mediated efflux even though paclitaxel was encapsulated into emulsion. The TB emulsion showed great potential as a promising vehicle for water-insoluble anticancer agent, paclitaxel.

• Journal of Pharmaceutical Investigation
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• 제38권1호
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• pp.39-43
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• 2008

Cyclosporin A (CyA), a potent immunosuppressive drug used in allogeneic transplants and autoimmune disease, is a typical water-insoluble drug. Recently, nanoparticle carriers were investigated to improve the intestinal absorption of drugs. In this study, CyA-loaded nanostructured lipid carriers (NLCs) were prepared from a hot o/w emulsion using the high pressure homogenization method. The NLCs were consisted of cationic lipids, solid lipids, liquid lipids (oils), surfactant and stabilizer. Encapsulation efficiency of CyA in NLCs was approximately 71%. The average particle size and zeta potential of NLCs were below 250 nm and above +40 mV, respectively. The morphology of NLCs was confirmed by transmission electron microscopy (TEM) analysis. Compared to the CyA powder, higher in vitro release of CyA from NLCs was observed after burst release within 30 min. Thus, CyA-loaded NLCs could be applied not only for parenteral route but also for gastrointestinal administration, which needs further investigation.

• Structural Engineering and Mechanics
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• 제37권2호
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• pp.197-213
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• 2011

Concrete is a heterogeneous material exhibiting quasi-brittle behaviour. While homogenization of concrete is commonly accepted in general engineering applications, a detailed description of the material heterogeneity using a mesoscale model becomes desirable and even necessary for problems where drastic spatial and time variation of the stress and strain is involved, for example in the analysis of local damages under impact, shock or blast load. A mesoscale model can also assist in an investigation into the underlying mechanisms affecting the bulk material behaviour under various stress conditions. Extending from existing mesoscale model studies, where use is often made of specialized codes with limited capability in the material description and numerical solutions, this paper presents a mesoscale computational model developed under a general-purpose finite element environment. The aim is to facilitate the utilization of sophisticated material descriptions (e.g., pressure and rate dependency) and advanced numerical solvers to suit a broad range of applications, including high impulsive dynamic analysis. The whole procedure encompasses a module for the generation of concrete mesoscale structure; a process for the generation of the FE mesh, considering two alternative schemes for the interface transition zone (ITZ); and the nonlinear analysis of the mesoscale FE model with an explicit time integration approach. The development of the model and various associated computational considerations are discussed in this paper (Part 1). Further numerical studies using the mesoscale model for both quasi-static and dynamic loadings will be presented in the companion paper (Part 2).

• 한국표면공학회지
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• 제37권6호
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• pp.350-359
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• 2004

Stress corrosion cracking(SCC) characteristics of shot-peened stainless steel containing Ti (0.09 wt%-0.92 wt%) fabricated by the vacuum furnace were investigated using SCC tester and potentiostat. The homogenization and the sensitization treatment were carried out at $1050^{\circ}C$ for 1hr and $650^{\circ}C$ for 5 hr. The samples for SCC were shot-peened using $\Phi$0.6 mm steel ball for 4 min and 10 min. Intergranular and pitting corrosion characteristics were investigated by using EPR and CPPT. SCC test was carried out at the condition of$ 288^{\circ}C$, 90 kgf pressure, water with 8 ppm dissolved oxygen, and $8.3xl0^{-7}$/s strain rate. After the corrosion and see test, the surface of the tested specimen was observed by the optical microscope, TEM and SEM. Specimen with Ti/C ratio of 6.14 showed high tensile strength at the sensitization treatment. The tensile strength decreased with the increase of the Ti/C ratio. Pitting and intergranular corrosion resistance increased with the increase of Ti/C ratio. Stress corrosion cracking strength of shot-peened specimen was higher than that of non shot- peened specimen. Stress corrosion cracking strength decreased with the increase of the Ti/C ratio.

• Biomolecules & Therapeutics
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• 제25권4호
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• pp.411-416
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• 2017

Paclitaxel (PTX) is a effectively chemotherapeutic agent which is extensively able to treat the non-small cell lung, pancreatic, breast and other cancers. But it is a practically insoluble drug with water solubility less than $1{\mu}g/mL$, which restricts its therapeutic application. To overcome the problem, hyaluronic acid-complexed paclitaxel nanoemulsions (HPNs) were prepared by ionic complexation of paclitaxel (PTX) nanoemulsions and hyaluronic acid (HA) to specifically target non-small cell lung cancer. HPNs were composed of ${\small{DL}}-{\alpha}$-tocopheryl acetate, soybean oil, polysorbate 80, ferric chloride, and HA and fabricated by high-pressure homogenization. The HPNs were $85.2{\pm}7.55nm$ in diameter and had a zeta potential of $-35.7{\pm}0.25mV$. The encapsulation efficiency was almost 100%, and the PTX content was 3.0 mg/mL. We assessed the in vivo antitumor efficacy of the HPNs by measuring changes in tumor volume and body weight in nude mice transplanted with CD44-overexpressing NCI-H460 xenografts and treated with a bolus dose of saline, $Taxol^{(R)}$, PTX nanoemulsions (PNs), or HPNs at a dose of 25 mg/kg. Suppression of cancer cell growth was higher in the PN- and HPN-treated groups than in the $Taxol^{(R)}$ group. In particular, HPN treatment dramatically inhibited tumor growth, likely because of the specific tumor-targeting affinity of HA for CD44-overexpressed cancer cells. The loss of body weight and organ weight did not vary significantly between the groups. It is suggest that HPNs should be used to effective nanocarrier system for targeting delivery of non-small cell lung cancer overexpressing CD44 and high solubilization of poorly soluble drug.

• 자원환경지질
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• 제53권3호
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• pp.221-234
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• 2020

금-은 천열수 광상의 유체 환경의 재구성을 위하여, 해남 일대에 위치한 모이산 광상에서 획득한 심도별 맥상 시료에 대하여, 변질-조직 양상, 유체포유물 microthermometry, 그리고 황철석 LA-ICP-MS 분석을 실시하였다. 맥상 시료에서 모암은 규화 및 석영-일라이트 변질양상이 확인되며, 석영맥은 모암으로부터 초기의 옥수-미립 석영-황철석에서 후기 맥중심의 자형 석영으로 발달된다. 일부 시료에서는 황철석과 함께 텔루라이드 광물이 함께 나타난다. 유체포유물은 염도가 0.18-2.24wt% 가량의 액상 수용액 포유물들이 주로 발견되며 일부 기체상 포유물 또한 발견된다. 유체포유물의 균질화 온도는 141-384℃ 범위에서 나타나며, 대체로 깊어질수록 균질화온도가 높아진다. 특히 금-은 침전이 집중된 고품위 구간에서는 얕아질수록 유체의 염도 및 균질화 온도가 낮아지며 또한 범위가 넓어지는 것을 볼 수 있다. 이를 통하여 함 금-은 유체의 압력하강으로 인한 열수의 비등 그리고 천수와의 혼합이 금-은 침전과 함께 이루어진 것으로 생각된다. 황철석의 LA-ICP-MS 분석을 통하여, 황철석 광물 내의 금-은 치환은 이루어지지 않음을 발견하였다. 하지만, 황철석 내의 금-은은 대부분 텔루라이드 혹은 에렉트럼 등 함 금은 광물의 포유물에 저장이 됨을 알 수 있었다. 깊이별 황철석 내 포획된 함 금-은 광물은 차이가 없었고, 포유물의 금-은 비율 또한 차이가 없음을 확인하였다.