• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.576-581
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• 2012

A 23 W continuous wavelength $CO_2$ laser system exited by a high-frequency LCC resonant converter is adapted to cut a biodegradable rope fabricated with polybutylene succinate. As the biodegradable rope consists of three twisted strands, the thickness changes relative to the position of the laser beam and we thus propose a method to determine exact cutting depth. In order to obtain the parameters related to the rope cutting, the experimental and theoretical cutting depths are compared and analyzed for a range of laser heat sources. The melted thickness and groove width of the cut biodegradable rope are also examined. The proposed theoretical cutting depth depends on the incident power and target velocity ratio. From these experimental results, the biodegradable rope with a diameter of 22 mm can be cut with a heat source of 50 J/cm resulting in a melted thickness of 1.96 mm and a groove width of 0.65 mm. The laser system is shown to be perfect tool for the processing of biodegradable rope without the occurrence of raveling.

• 한국전기전자재료학회논문지
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• 제26권12호
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• pp.920-923
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• 2013

In this paper, the characteristics of a carbon nanotube composite heat sink proposed to replace the advanced Al heat sinks for LED lighting devices were studied. Proposed CMP-PLA heat sink was made by mixing 20~70 wt% carbon nanotube, 20~70 wt% bio-degradable polymer of melt-blended PLA (poly lactic acid) and PBS (poly butylene succinate) and PLA nucleating agents composed of the mixture of soybean oil and biotites, at $150{\sim}220^{\circ}C$ with 1,000~1,500 rpm. Optical and electric characteristics of 7.5 W LED lighting devices using heat sinks with such prepared CMP-PLA were investigated. And, the properties of the heat, which was not released from the CMP-PLA type heat sinks, was also investigated. The color temperature of LED lighting devices using the CMP-PLA heat sinks was 5,956 K, which is x= 0.32 and y= 0.34 in the XY chromaticity, and the color rendering index was 75. The luminous flux and the luminous efficiency of LED lighting devices using the CMP-PLA heat sinks was 540.6 lm and 72.68 lm/W respectively. Measured initial temperature of the heat sinks was $27^{\circ}C$, and their temperature increased as time to be saturated at $52^{\circ}C$ after an hour.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.93-97
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• 2002

Poly(ethylene glycol)-phosphatidylethanolamine conjugate (PEG-PE) has been used in preparing longcirculating liposomes. As a substitute for PEG-PE which can also be used in the long-circulating liposome formualtions, but can be prepared more readily with a lower cost, PEG-Phe-Chol was synthesized from PEG, phenylalanine, and cholesterol. The addition of the PEG derivative to distearoylphosphatidylcholine (DSPC) led to the formation of mixed micelles as well as liposomes when the derivative content was 10 mol% or greater. On the other hand, the addition of just 5 mol% PEG-Phe-Chol to dioleoylphosphatidylethanolamine (DOPE) generated mixed micelles as well as liposomes, but the formation of mixed micelles was completely inhibited by the addition of cholesterol. The leakage of entrapped calcein out of DOPE/cholesterol (7/3) liposomes containing 5 mol% PEG-Phe-Chol was about 45% during the incubation time for 24 h in 50% rabbit plasma, which was similar to that of the same liposomes containing 5 mol% PEG-dipalmitoylphosphatidylethanolamine (DPPE) under the identical conditions.

• 한국조리학회지
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• 제3권
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• pp.239-257
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• 1997

This study investigated the effect of the addition of alcohol on the quality change of Chungkukjang during the aging, The Cung-kuk-jang was made by the degree of 3, 5, 10%, respectively, and determined NH2-N, NH3-N, total acidity, cell numbers, lactate, succinate and phenolic acid to measure the change of flavor component in the aging of 2$0^{\circ}C$. 1. In the treatment groups of different amount of alcohol and salt added and aging period of Chung-kuk-hang, NH2-N was more decreased with more addition of alcohol and salt in the 3-and 10-day of aging. NH3-N was increased gradually in the addition of up to 2.0% alcohol and then decreased in the 3-and 10-day of aging. 2. In the treatment groups of different amount of alcohol added and aging period Chung-kuk-hang, the total acidity was more decreased with more addition of alcohol and higher degree of salt. Cell number was decreased rapidly with the addition of 1.0% alcohol in the 3-day and then decreased relatively and in the 10-day of aging, and it was increased with the addition of alcohol 3. With the addition of alcohol and the different growing temperature, the content of phenolic acid was more browning changed at 3$0^{\circ}C$ than that of at 2$0^{\circ}C$ and the phenol content of each group was decreased with increasing the addition amount of alcohol. Thus, the more addition of alcohol amount would the more extend the period of Chung-kuk-hang aging.

• Applied Microscopy
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• 제14권2호
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• pp.1-14
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• 1984

Chick embryos received a single injection of actinomycin D($0.1{\mu}g,\;0.05{\mu}g\;or\;0.1{\mu}g$) or puromycin($10.0{\mu}g,\;30.0{\mu}g\;or\;50.0{\mu}g$) into the yolk sac of Arbor acres chick embryos either prior to incubation or at certain periods of time (48, 96 and 144 hours) after incubation. After 10days of incubation, surviving embryos were investigated morphologically and biochemically. Embryos treated with actinomycin D or puromycin showed a high mortality when they were exposed prior to incubation and at 48 hours after incubation. Electron micrographs of chondrocytes in tarso-metatarsal of antibiotics (actinomycin D or puromycin) treated embryos showed the destruction of cytoplasm and nuclei when they were exposed prior to incubation. Endoplasmic reticulum was expanded and mitochondria were damaged in chondrocytes of surving embryos treated with low doses at 48 hours, 96 hours or 144 hours after incubation. The activities of enzymes such as lactate dehydrogenase, malate dehydrogenase and succinate dehydrogenase in embryos treated with actinomycin D or puromycin were much less than those of the saline treated group. Also, the amounts of DNA, RNA and protein were greatly decreased.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.269-273
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• 2001

This study presents a new formulation method for improving DNA transfection effi-ciency using a fusogenic peptide and polyethylene glycol-grafted polyethylenimine. Succinimidyls succinate polyethylene glycol (PEG-SSA) was conjugated with polyethylenimine(PEL). PEL is well known for a good endosomal escaping and DNA condensign agent. The positively charged syn-thetic fusogenic peptide, KALA was coated on the negatively charged PEG-g-PEI/DNA and PEI/DNA complexes. The KALA/PEI/ DNA complexes exhibited aggregation behavior at higher KALA coating amount with an effective diameter of around 1,000 nm. However, the LALA/PEG-g-PEI/DNA complexes were 100-300 nm in size with a surface zeta-potential (ζ)value of about +20mV. The conjugated PEG molecules suppressed any KALA-mediated inter-particle aggregation, and thereby improved the transfection efficiency, Consequently, the transfection efficiency of the KALA/PEG-g-PEI/DNA complexes was obtained by utilizing both the fusogenic activity of KALA and the steric repulsion effect of PEC.

• BMB Reports
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• 제41권3호
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• pp.242-247
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• 2008

MSS, a comprising mixture of maesil (Prunus mume Sieb. et Zucc) concentrate, disodium succinate and Span80 (3.6 : 4.6 : 1 ratio) showed a significant improvement of memory when daily administered (460 mg/kg day, p.o.) into the normal rats for 3 weeks. During the spatial learning of 4 days in Morris water maze test, both working memory and short-term working memory index were significantly increased when compared to untreated controls. We investigated a molecular signal transduction mechanism of MSS on the behaviors of spatial learning and memory. MSS treatment increased hippocampal mRNA levels of NR2B and TrkB without changes of NR1, NR2A, ERK1, ERK2 and CREB. However, the protein levels of pERK/ERK and pCREB/CREB were all significantly increased to $1.5{\pm}0.17$ times. These results suggest that the improving effect of spatial memory for MSS is linked to MAPK/ERK signaling pathway that ends up in the phosphorylation of CREB through TrkB and/or NR2B of NMDA receptor.

• 생약학회지
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• 제5권4호
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• pp.211-216
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• 1974

시판(市販) ${\ulcorner}$김${\lrcorner}$의 유리(遊離) 지방산(脂肪酸)을 20% DEGS (diethyleneglycol succinate) 칼람을 장치(裝置)한 가스 크로마토그라피를 사용하여 separation factor 및 oxymereuration-demercuration법(法)을 이용(利用)함으로써 23종(種)의 지방산(脂肪酸)을 확인(確認)하였으며, 가스 크로마로그람의 면적(面積)으로부터 그들을 각각 정량(定量)하였다. 진기(珍奇)한 산(酸)은 존재(存在)하지 않았으며, $C_{22}F{\times}1,\;C_{26}$, oleic acid, palmitic acid가 거의 60%를 차지했다. Oxymercuration-demercuration법(法)에 의(依)하여 분리(分離)된 불포화 지방산(脂肪酸)중에서 $C_{13}F{\times}1,\;C_{18}F{\times}1,\;C_{20}F{\times}1$는 명명(名名) 두 개(個)의 기하이성체(幾何理性體)가 존재하는 것으로 추정(推定)된다. 쇄상 포화 지방산(脂肪酸) 및 $F{\times}1$ 및 $F{\times}2 $의 쇄상 불포화 지방산(脂肪酸)은 $R_{USEVA}-A_{TANSONA}$ 및 $M_{URRAY}$등이 언급(言及)한 바와 같이 지방산(脂肪酸)의 탄소수(炭素數)에 대해서 $t_R\;(retention time)$을 semi-log plot를 하였을때 직선(直線)을 주었다.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.54-68
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• 2011

$^1H$ nuclear magnetic resonance (NMR) spectroscopy of biological samples has been proven to be an effective and nondestructive approach to probe drug toxicity within an organism. In this study, ketoprofen toxicity was investigated using $^1H$-NMR spectroscopy coupled with multivariate statistical analysis. Histopathologic test of ketoprofen-induced acute gastrointestinal damage in rats demonstrated a significant dose-dependent effect. Furthermore, principal component analysis (PCA) derived from $^1H$-NMR spectra of urinary samples showed clear separation between the vehicle-treated control and ketoprofen-treated groups. Moreover, PCA derived from endogenous metabolite concentrations through targeted profiling revealed a dose-dependent metabolic shift between the vehicle-treated control, low-dose ketoprofen-treated (10 mg/kg body weight), and high-dose ketoprofen-treated (50 mg/kg) groups coinciding with their gastric damage scores after ketoprofen administration. The resultant metabolic profiles demonstrated that the ketoprofen-induced gastric damage exhibited energy metabolism perturbations that increased urinary levels of citrate, cis-aconitate, succinate, and phosphocreatine. In addition, ketoprofen administration induced an enhancement of xenobiotic activity in fatty oxidation, which caused increase levels of N-isovalerylglycine, adipate, phenylacetylglycine, dimethylamine, betaine, hippurate, 3-indoxylsulfate, N,N-dimethylglycine, trimethyl-N-oxide, and glycine. These findings demonstrate that $^1H$-NMR-based urinary metabolic profiling can be used for noninvasive and rapid way to diagnose adverse drug effects and is suitable for explaining the possible biological pathways perturbed by nonsteroidal anti-inflammatory drug toxicity.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1327-1332
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• 2004

The hemA gene encoding 5-aminolevulinic acid synthase (ALAS) was cloned from Rhodobacter capsulatus, and its nucleotide sequence was determined. DNA sequencing data revealed one open reading frame coding for a protein with 401 amino acids that displayed high similarity to the amino acid sequences of other known ALASs. The hemA gene was then cloned and expressed under the control of constitutive promotor in E. coli. The recombinant E. coli strain was able to accumulate 5-aminolevulinic acid to 21 mM in the liquid medium supplemented with 45 mM glycine and 120 mM succinate. In addition, a marked effect of the pH of the culture medium on ALA production was observed, and the optimum pH for culture medium was determined to be 5.8-6.3.