• Nuclear Engineering and Technology
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• 제31권4호
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• pp.391-400
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• 1999

A conceptual core design of the 1,300MWe KNGR (Korean Next Generation Reactor) without using soluble boron for reactivity control was developed to determine whether it is technically feasible to implement SBF (Soluble Boron Free) operation. Based on the borated KNGR core design, the fuel assembly and control rod configuration were modified for extensive use of burnable poison rods and control rods. A new fuel rod, in which Pu-238 had been substituted for a small amount of U-238 in fuel composition, was introduced to assist the reactivity control by burnable poison rods. Since Pu-238 has a considerably large thermal neutron capture cross section, the new fuel assembly showed good reactivity suppression capability throughout the entire cycle turnup, especially at BOC (Beginning of Cycle). Moreover, relatively uniform control of power distribution was possible since the new fuel assemblies were loaded throughout the core. In this study, core excess reactivity was limited to 2.0 %$\delta$$\rho$ for the minimal use of control rods. The analysis results of the SBF KNGR core showed that axial power distribution control can be achieved by using the simplest zoning scheme of the fuel assembly Furthermore, the sufficient shutdown margin and the stability against axial xenon oscillations were secured in this SBF core. It is, therefore, concluded that a SBF operation is technically feasible for a large sized LWR (Light Water Reactor).

• Carbon letters
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• 제27권
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• pp.18-25
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• 2018

In this study, graphene oxide(GO) was used as drug carriers to amorphize poorly watersoluble drugs via a co-spray drying process. Two poorly water-soluble drugs, fenofibrate and ibuprofen, were investigated. It was found that the drug molecules could be in the graphene nanosheets in amorphous or nano crystalline forms and thus have a significantly enhanced dissolution rate compared with the counterpart crystalline form. In addition, the dissolution of the amorphous drug enwrapped with the graphene oxide was higher than that of the amorphous drug in activated carbon (AC) even though the AC possessed a larger specific surface area than that of the graphene oxide. The amorphous formulations also remained stable under accelerated storage conditions ($40^{\circ}C$ and 75% relative humidity) for a study period of 14 months. Therefore, graphene oxide could be a potential drug carrier and amorphization agent for poorly water-soluble drugs to enhance their bioavailability.

• 한국축산식품학회지
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• 제23권1호
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• pp.86-95
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• 2003

비타민 E에 의한 육색소의 산화 안정성 향상 기작을 정리하였다. 지용성 산화제인 $\alpha$-토코페롤이 수용성 단백질인 옥시마이오글로빈을 보호하는 원리가 밝혀지고 있다. 최근의 연구들에서 $\alpha$-토코페롤이 세포막 지방산화의 2차 산화물들의 방출을 지연시켜 옥시마이오글로빈 산화를 억제시키고 식육의 바람직한 육색을 유지시킨다는 증거가 제시되고 있다. 지방산화물의 한 그룹인 $\alpha$,$\beta$-분포화 알데하이드들은 단백질과 서로 결합하는 역할을 하여 옥시마이오글로빈의 산화를 증진시키는 것으로 밝혀졌다. 만약 $\alpha$-토코페롤이 이런 활동적인 알데하이드들의 발생을 지연시킨다면 이런 지방산화물들이 옥시마이오글로빈의 산화에 미치는 영향도 억제될 것이다. 또한$\alpha$-토코페롤은 메트마이오글로빈의 환원에 작용하여 쇠고기의 육색 안정성 유지에 일정부분 역할을 담당하는 것으로 사료된다.

• 약학회지
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• 제37권4호
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• pp.370-382
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• 1993

In order for formulation of rectal containing OMZ, the OMZ suppositories were prepared using water-soluble base, PEG 4000 base and oil-soluble base, Witepsol H 15. Chemical stability of OMZ in suppositories was increased when Witepsol H 15 was used as a suppository base and arginine was added as a stabilizer. The decomposition of OMZ in suppository bases followed the first-order kinetics and their rate constants were 0.11 day $^{1}(t_{1/2}$=/6.25 days) for Witepsol H 15 suppository and 0.48 day $^{1}(t_{1/2}$=/1.43 days) for PEG 4000 suppository, respectively. On the other hand, the decomposition rate constants of Witepsol suppository and PEG suppository stabilized with arginine were 3.89$\times$10$^{-3}$(t$_{1/2}$=171.1 days) and 8.76$\times$10$^{-3}$ day $^{1}(t_{1/2}=79.9 days), respectively. Shelf-lives of the Witepsol and PEG suppositories stabilized with arginine were t$_{90%}$=291.8 days and t$_{90%}$=282.1 days at $35^{\circ}C$ and 75% RH, respectively. The dissolution test of OMZ suppositories was performed by rotating dialysis cell(RDC) method and the release rate constant was calculated by the simplified Higuchi's equation, Q'=K' t$^{1/2}$. Dissolution of OMZ from suppositories was augmented as arginine was added, particle size of OMZ was reduced and a suitable surfactant such as SLS was added. RDC method was more appropriate and available than Paddle method to evaluate the dissolution rate of lipophilic-base suppositoies. Arginine was found to be a very useful exipient for the enhancement of stability and dissolution of OMZ in suppositories.

• Journal of Animal Science and Technology
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• 제58권9호
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• pp.34.1-34.9
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• 2016

Background: By-products of pickled radish (BPR) are considered food waste. Approximately 300 g/kg of the total mass of raw materials becomes BPR. Production of pickled radish has grown continuously and is presently about 40,000 metric tons annually in Korea. The objective of the present study was thus to explore the possibility of using BPR as a ruminant feed ingredient. Results: BPR contained a large amount of moisture (more than 800 g/kg) and ash, and comprised mostly sodium (103 g/kg DM) and chloride (142 g/kg DM). On a dry matter basis, the crude protein (CP) and ether extract (EE) levels in BPR were 75 g/kg and 7 g/kg, respectively. The total digestible nutrient (TDN) level was 527 g/kg and the major portion of digestible nutrients was carbohydrate; 88 % organic matter (OM) was carbohydrate and 65 % of total carbohydrate was soluble or degradable fiber. The coefficient of variation (CV) of nutrient contents among production batches ranged from 4.65 to 33.83 %. The smallest CV was observed in OM, and the largest, in EE. The variation in CP content was relatively small (10.11 %). The storage stability test revealed that storage of BPR at $20^{\circ}C$ (room temperature) might not cause spoilage for 4 d, and possibly longer. If BPR is refrigerated, spoilage can be deferred for 21 d and longer. The in vitro ruminal fermentation study showed that substitution of annual ryegrass straw with BPR improved ruminal fermentation, as evidenced by an increase in VFA concentration, DM degradability, and total gas production. Conclusion: The major portion of nutrients in BPR is soluble or degradable fiber that can be easily fermented in the rumen without adverse effects, to provide energy to ruminant animals. Although its high sodium chloride content needs to be considered when formulating a ration, BPR can be successfully used as a feed ingredient in a ruminant diet, particularly if it is one component of a total mixed ration.

• 한국식품과학회지
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• 제50권3호
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• pp.324-330
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• 2018

본 연구에서는 서로 다른 성질을 지닌 기름(MO, CO, PO)을 선정한 후 산화방지제(아스코브산, 토코페롤)의 종류와 농도를 달리한 베타카로텐 함유 나노에멀션을 제조하여, 산화안정성을 검토하였다. 베타카로텐 나노에멀션은 낮은 pH에 비하여 높은 pH에서 화학적으로 더 안정하였다. 또한 베타카로텐의 산화는 기름의 특성에 많은 영향을 받았으며, 지방산 사슬길이가 길며 포화 지방산 함량이 낮은 CO를 유상(oil phase)으로 사용할 경우 베타카로텐 산화를 더욱 가속화시키는 것으로 나타났다. 에멀션 내의 베타카로텐의 분해는 아스코브산과 토코페롤 산화방지제를 첨가함으로써 지연시킬 수 있었다. 그러나 베타카로텐을 함유한 산성 상태의 음료와 식품을 제조하고 이를 장기간 보존하기 위해서는 높은 농도의 산화방지제 첨가가 요구됨을 확인하였다.

• Journal of Pharmaceutical Investigation
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• 제22권2호
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• pp.105-113
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• 1992

To improve the solubility and dissolution rate of trimethoprim (TMP), which is slightly soluble drug, its inclusion complexes were prepared and studied in this experiment. Inclusion complexes of TMP with ${\beta}-cyclodextrin$ and ${\beta}-cyclodextrin$ polymer (CDPS) were prepared according to Fenyvesi method. These were compared with TMP and its physical mixture with CDPS. Water, diluted hydrochloric acid and phosphate buffer solution were used as dissolution media. And accelerated stability test was studied at $50,\;70\;and \;80^{\circ}C$. It was found that solubility and dissolution rate of inclusion complexes were increased in water. Especially, the solubility and dissolution rate of TMP was found to be markedly increased by inclusion complexation with CDPS. In stability test, ${\beta}-cyclodextrin$ inclusion complexes were more or less stable than TMP alone. This tendency was not led in CDPS. Consequently, CDPS was useful in increasing dissolution rate and stability of TMP.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1196-1199
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• 2004

A bacterium, isolated from rabbit's waste and identified as Cellulomonas sp., had cellulase and thermostable $\alpha$-amylase activity when grown on wheat bran. Maximum activity of thermostable $\alpha$-amylase was obtained by adding $3\%$ soluble starch. However, soybean oil (1 ml $1^{-1}$) could increase the production of $\alpha$-amylase and cellulase in 'wheat bran. The $\alpha$-amylase was characterized by making a . demonstration of optimum activity at $90^{\circ}C$ and pH 6- 9, with soluble starch as a substrate. The effect of ions on the activity and the stability of this enzyme were investigated. This strain secreted carboxymethyl cellulase (CMCase), cellobiase ($\beta$­glucosidase), and filter paperase (Fpase) during growth on wheat bran. Carboxymethy1cellulase, cellobiase, and Fpase activities had pH optima of 6, 5.5, and 6, respectively. CMCase and cellobiase activities both had an optimum temperature of $50^{\circ}C$, whereas Fpase had an optimum temperature of $45^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• 제28권3호
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• pp.159-164
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• 1998

The O/W and W/O emulsions containing Scutellariae Radix extract(SRE) which is very slightly soluble in oil phases and sparingly soluble in water phases, were prepared by homogenizing water and oil phases with emulsifier. The diameters of emulsion were ranged from 100 to $300\;{\mu}m$. The viscosity of W/O emulsion was higher than that of O/W emulsion. W/O emulsion was more stable than O/W emulsion which was gradually degraded when tested by centrifuge method and temperature tolerance method at $50^{\circ}C$. The antibacterial activity of two emulsions was not significantly different from that of aqueous solution of SRE, and showed similar MIC and bacterial growth inhibition rate.

• 한국식품영양학회지
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• 제9권2호
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• pp.143-150
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• 1996

The studies was carried out to investigate ripening degree and functional properties of EMC produced with pancreatic protease and palatase ML. During production of EMC, the amounts of free amino acid and free fatty acid were increased with increasing the reaction time. The amount of total nitrogen(T-N) and water soluble nitrogen(WSN) were increased with increasing time. EMC had contents of 1.79eA T-N and 0.52o WSN at 60 min of hydrolysis time. SRI and FRI value had also a similar correlationship. On the gel filtration, 2 kinds of soluble proteining capacity was also shown in alkali solution. Furthermore the foaming stability had the same result as that of the solubility. The water absorption of EMC showed the highest level at pH 4.0 and 5.0.