• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.83-87
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• 2021

Antimicrobial activity of an aqueous extract from Caesalpinia sappan L. was investigated against skin flora such as Escherichia coli, Staphylococcus aureus, Cutibacterium acnes, and Malassezia furfur. The yield and polyphenol content of the aqueous extract were 14.01±0.81% and 487.5±19.69 ㎍/mg-extract, respectively. The minimum inhibitory concentration of the aqueous extract against E. coli, S. aureus, C. acnes, and M. furfur was 0.875, 1.750, 1.750, and 1.750 mg/mL, respectively. In disc diffusion test, the aqueous extract of C. sappan L. increased the clear zone in a dose-dependent manner. The aqueous extract inhibited the microbial growth in a concentration-dependent manner.

• Analytical Science and Technology
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• v.20 no.3
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• pp.237-245
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• 2007

The presence of benzene in 31 products of vitamin drinks purchased from 20 retail outlets was determined using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The sample (25 ml) was stirred at 1200 rpm for 4 min using a magnetic bar with a $100{\mu}m$ SPME fiber as an adsorbent for benzene which was then desorbed from the fiber for 1 min in the GC injector. Quantitation was achieved using the standard addition method. The limit of detection was determined as 0.56 ng/ml and over a concentration range 0-40 ng/ml the coefficient of correlation was greater than 0.999. The concentration of benzene in the drinks examined was in the range not detectable to 47.35 ng/ml. Benzene was detected in 15 of the drinks with concentration in 5 of them greater than 10 ng/ml which is the limit set for the presence of benzene in the Drinking Water Regulations. The concentrations of benzene in the 5 drinks which exceeded the limit of 10 ng/ml were 16.99, 35.14, 16.03, 47.35 and 14.28 ng/ml respectively.

• Analytical Science and Technology
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• v.17 no.1
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• pp.69-81
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• 2004

The formation pattern of DBPs (disinfection by-products) in raw water treated with hypochlorite, chlorine disinfectant was studied. TOC (total organic carbon), residual chlorine, turbidity and 14 DBPs in raw water from Han-river and Nakdong river during 1 ~ 14 days were determined. Total DBPs in Han river was 101.3 ng/mL (789.6 nM) after 7days and THMs (trihalomethanes) are the dominant portion of 68%. HAAs (haloacetic acids) and chloral hydrate were determined 19% and 10% respectively. In Nakdong river total DBPs was 98.4 ng/mL (678.6 nM) and dominant class was HAAs. (55.8 ng/mL, 57%) THMs(34%) and N-compounds like HANs (haloacetonitriles, 5%) and chloropicrin were increased. It may be explained that high concentration of NH4-N in Nakdong river react with chlorine produced chloramine and this formed different pattern of DBPs. As a result, total DBPs formation pattern depends on raw water and disinfectant and in generally the initial concentration of acidic HAAs was high and THMs was increased gradually.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.45-53
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• 2012

Lactobacillus acidophilus isolated from the feces of a 7-day-old breast-fed infant was characterized to examine the scope of its commercial use. Forty-three Lactobacillus strains, which could grow at pH 5.5, were isolated. From these Lactobacillus isolates, 14 Lactobacillus strains were selected, which demonstrated more than 80% viability and homofermentative lactic fermentation. Finally, 9 L. acidophilus strains (NB 201~NB 209) were identified as candidate strains based upon biochemical properties, carbohydrate utilization, and cellular fatty acid composition. L. acidophilus isolates demonstrated a survival rate of more than 80% when exposed to pH 2.5 for 2 h. In particular, L. acidophilus NB 204 showed a strong acid tolerance, with a 71% survival rate even at pH 2.0. L. acidophilus isolates also manifested high bile acid tolerance; more than 87% of the cells survived on agar containing 1% bile extract, except for L. acidophilus NB 206, which showed a 73% survival rate. All L. acidophilus isolates were confirmed to have proteolytic activity; L. acidophilus NB 204 and NB 209 yielded higher levels of TCA-soluble peptides and free amino acids. The ${\beta}$-galactosidase activity of the L. acidophilus isolates was in the range of 1.97~2.45 units/mL.

• Journal of Life Science
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• v.14 no.1
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• pp.115-120
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• 2004

Lepista nuda is a world-wide species which has and international reputation as a excellent edible species. In this study, we investigated the genetic variation and taxonomic relationship of L. nuda and other five Tricholomataceae species were analyzed by random amplied polymorphic DNA (RAPD). 15 kinds of random primers were used. The distance matrix was calculated using UPGMA and phyolgenetic relationship were inferred by neighnor-joining (NJ) method. Various bands of 100bp∼1600bp were observed in electrophoretic patterns of RAPD. Nei's genetic distance was calculated using a total of 228 DNA bands identified, and phylogenetic tree was made. The Nei's genetic variations of L. nuda, Lepista surdida, Collybia peronata, Collybia confluens, Lyophyllum cinerascens, Laccara laccata were 0∼21.3%, 21.2∼28.0%, 15.4∼23.0%, 14∼21.8%, 16.5∼34.6%, and 12.4∼27.4%, respectively The consistency index, the retention index and homoplasy index were 0.5217, 0.5769 and 0.5156, respectively. Also, two groups could be made by NJ tree. The genetic distance between L. nuda and C. confluens was closer than that between L. nuda and L. sordida.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.108-113
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• 2019

In this study, the decomposition characteristics of perfluorinated compounds generated in semiconductor manufacturing process were investigated by using a high temperature plasma. The analysis results revealed that $CF_4$ and $SF_6$ showed the highest efficiency at 12.8 kW power, but no significant difference was observed at the power above. Experimental results showed that the maximum efficiency was obtained at the flow rate of about 14 mL/min and the treatment efficiency decreased as the flow rate increased or decreased with respect to the flow rate of 14 mL/min. As a result, the decomposition characteristics of perflurocompounds (PFCs) using a high temperature plasma could be grasped, and also the basis for the treatment of PFCs and greenhouse gases generated in the semiconductor manufacturing process could be obtained.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.561-567
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• 1993

The twelve macrocycle (L) complexes of cadmium(II) nitrate have been synthesized: $CdL(NO_3)_2$. All the complexes have been indentified by elemental analysis, electric conductivity measurements, IR and NMR spectroscopic techniques. The molar electric conductivities of the complexes in water and acetonitrile solvent were in the range of 236.8-296.1 $cm^2{\cdot}mol^{-1}{\cdot}ohm^{-1}$ at 25$^{\circ}$C. The characteristic peaks of macrocycles affected from Cd(II) were shifted to lower frequencies as compared with uncomplexed macrocycles. A complex with 1,4,8,11-tetrakis(methylacetato)-1,4,8,11-tetraaza cyclodecane (L4) exhibited two characteristic bands such as strong stretching (1646 $cm^{-1})$, and weaker symmetric stretching band (1384 $cm^{-1})$. NMR studies indicated that all nitrogen donor atoms of macrocycles have greater affinity to cadmium(II) metal ion than do the oxygen atoms. The $^{13}$C-resonance lines of methylene groups neighboring the donor atom such as N and S were shifted to a direction of high magnetic field and the order of chemical shifts were $L_1 < L_2 < L_3 < L_6 < L_4$. Also the chemical shifts values were larger than those of methylene groups bridgeheaded in side-armed groups. This result seems due to not only the strong interaction of Cd(Ⅱ) with nitrogen donors according to the HSAB theory, but weak interaction of Cd(Ⅱ) and COO- ions or sulfur which is enhanced by the flexible methylene spacing group in side-armed groups. Thus, each additional gem-methyl pairs of L_3, L_4\;and\; L_6$ macrocycles relative to $L_1, L_2,\;and\;L_5$ leads to an large enhancement in Cd(II) affinity. ^{13}C$-NMR spectrum of the complex with $L_{12}$ (1,5,9,13-tetracyclothiacyclohexadecane-3,11-diol) reveals the presence of two sets of three resonance lines, and intensities of the each resonance line have the ratio of 1 : 2 : 2. This molecular conformation is predicted as structure of tetragonal complex to be formed by coordinating two sulfur atoms and the other two sulfur atoms which is affected by OH-groups.

• KSBB Journal
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• v.8 no.5
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• pp.452-456
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• 1993

This study was carried out to optimize the fermentation conditions for direct alcohol fermentation of xylose by Pichia stipitis CBS 5776. The best cell growth and the ethanol production were obtained under 0.05 VVM aeration and 300rpm agitation at $30^{\circ}C$ using 100 g/l xylose medium of the initial pH 5.0. In the above condition, the maximum specific growth rate and maximum cell concentration were 0.14hr-1 and $1.3 \times109$ cells/ml, respectively. Pichia stipitis CBS 5776 also produced 40.2g/l ethanol utilizing about 96% of 100g/l xylose after 72hr fermentation. At this point, the overall volumetric ethanol productivity was 0.56g/1-hr and the ethanol yield was 0.42 g-ethanol/g-xylose consumed, which corresponds to 82% of the theoretical yield.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.51-56
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• 2004

Age and growth of three-lined tonguefish (Cynoglossus abbreviatus) were studied using samples from the waters off Yosu, Korea, from June to December, 2001. Sagittal otoliths had relatively clear annuli. Each annulus was formed once a year in April. The peak of the gonadosomatic index occurred also in April. The oldest fish observed in this study was 5 years old for females and 4 years old for males. The relationship between the otolith radius (R) and total length (L) was as follows: L=14.921R-2.5318 for females and L=13.527R-0.5584 for males. The relationship between total length and body weight (W) was as follows: $W=0.0008L^{3.54}$ for females and $W=0.0029L^{3.14}$ for males. The growth in length of the fish was expressed by the von Bertalanffy's growth equation as: $$L_t=44.54(1-e^{-0.16(t+2.69)})\;for\;females\;and\;L_t=41.52(1-e^{-0.15(t+3.34)})\;for\;males$$.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.12-16
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• 2003

This paper presents a compensation method for a temperature-dependent gain tilt in L-band erbium-doped fiber amplifier using a voltage-controlled attenuator. The gain tilts in the L-band of 1570-1605 nm due to a temperature change have negative slopes, whereas they have positive slopes for the increasing optical input powers in a saturation region. The proposed method utilizes these opposite gain variations to compensate for the gain tilt over a wide range of temperature. While applying forty channels with a channel spacing of 100 GHz in the L-band and changing the ambient temperature from 0 to $50^{\circ}C$, the compensation method maintained the gain deviation within 1 dB.