• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.250-256
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• 1998

D-Tagatose production from D-galactose was investigated using 35 type strains of American Culture Type Collection (ATCC) and Korean Collection for Type Cultures (KCTC) which have potential to produce D-tagatose. Enterobacter agglomerans ATCC 27987 was selected as a D-tagatose producing strain due to its short fermentation time and high production of D-tagatose. Optimization of the culture conditions for D-tagatose production by E. agglomerans ATCC 27987 was performed. Among various carbon sources, D-galactose was the most effective carbon source for D-tagatose production. As the D-galactose concentration was increased, cell growth and D-tagatose production increased. Effect of nitrogen sources on D-tagatose production was studied. Of inorganic nitrogen sources, ammonium sulfate was effective one for D-tagatose production and yeast extract was the most suitable organic nitrogen nutrient. The concentrations of inorganic compounds such as KH$_2$PO$_4$, K$_2$HPO$_4$, and MgSO$_4$$.$7H$_2$O were also optimized for D-tagatose production. The optimal medium was determined to contain D-galactose of 20 g/l, yeast extract of 5.0 g/l, (NH$_4$)$_2$SO$_4$ of 2.0 g/l, KH$_2$PO$_4$ of 5.0 g/l, K$_2$HPO of 5.0 g/l, and MgSO$_4$$.$7H$_2$O of 5 mg/l. The optimal environmental conditions in a 250-$m\ell$ flask were found to be pH of 6.0, temperature of 30$^{\circ}C$, and agitation speed of 150 rpm. D-tagatose of 0.41 g/l could be obtained in 24 h from 20 g/l D-galactose at the optimal culture condition without induction and cell concentration.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.59-64
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• 2015

Purpose: Lactate has two optical isomers, L-lactate and D-lactate. In human L-lactate is the most abundant enantiomer of lactate. As plasma and urinary levels of L-lactate is associated with inherited metabolic disorders in general, D-lactate have been linked to the presence of diabetes and inflammatory bowel disease. Previously developed techniques have shown several limitations to further evaluate D-lactate as a biomarker for this condition. In this paper, we describe a highly sensitive, specific and fast liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the analysis of D-, L-lactate in urine. Methods: D- and L-lactate were quantified using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) with labelled internal standard. Samples were derivatized with (+)-O,O'-diacety-L-tartaric anhydride (DATAN) and seperated on a Poroshell 120 EC-C18 column. Results: Quantitative analysis of D-, and L-lactate was achieved successfully. Calibration curves were linear (r>0.999) over $0.5-100{\mu}g/mL$. Stabilities for samples were within the 10% varation. Inter- and Intra-day assay variations were below 10%. Conclusion: The presented method proved to be suitable for the quantitation of D- and L-lactate and opens the possibility to explore the use of D-lactate as a biomarker.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1119-1125
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• 2004

The effect of hemicellulose extracted from soy fiber on the level of blood glucose and serum cholesterol in the streptozotocin-induced diabetic rat were investigated. The experimental plots were divided to cellulose group (control, 0.5％ hemicellulose group (H-l) and 1％ hemicellulose group (H-2) group. The groups were fed for 6 weeks, then fed for 1 week more after streptozotocin injection. Food intakes, weight gain and food efficiency ratio of H-2 group were higher, while water intakes and liver weight were lower than those of control and H-l group. The content of blood glucose and urine glucose were 212.8 mg/dL, 0.97 mg/dL in the control group, 160.5 mg/dL, 0.53 mg/dL in the H-l group, 141.0 mg/dL, 0.35 mg/dL in the H-2 group, respectively. There was no significantly difference in the content of neutral lipid, while the content of total serum cholesterol was 101.6 mg/dL in the control group, 73.8-78.4 mg/dL in the hemicellulose groups. The content of serum HDL-cholesterol in the all experimental groups showed no significantly difference showing 39.8-44.7 mg/dL. HTR and atherogenic index were 0.44 and 1.27 in the control group, but 0.54 and 0.46-0.85 in the hemicellulose groups, respectively.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.286-291
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• 2003

We investigated the effects of molting-hormone insecticide tebufenozide on D7 (the day of hatching from egg) larvae of the midge Chironomus riparius in growth developments. D7 instar larvae were exposed test concentrations were chosen control, 10${\mu}g \;L^{-1}$, 30${\mu}g \;L^{-1}$, 60${\mu}g \;L^{-1}$ and 100${\mu}g \;L^{-1}$ of tebufenozide. In general, dead larvae showed 16% on the next day after insecticide treatments (D12), and observed 44% from D12 to D16 in this exposed days. Dead larvae of C. riparius was abruptly increased on D12 and also continuously increased along the days in 10${\mu}g \;L^{-1}$ treatments. The converged day was from D12 to D16 at move 30${\mu}g \;L^{-1}$ treatments in this study. Therefore, dead larvae obviously increased along these concentrations of tebufenozide. In control condition,78% of the test individuals have grown the pupae. But the larvae have developed the pupa stage from 5% to 17% of the test organism in 10${\mu}g \;L^{-1}$ and 30${\mu}g \;L^{-1}$ treatments. And 75% of the test individuals was arrived the adult through the molting process in control condition. While the other condition was rarely observed the adult. Usually, the emerged period of the test individuals was gathered the D26-D29 in control. The dead pupa showed from D19 to D20 in 30${\mu}g \;L^{-1}$ treatments, D32 in control and D33 in 10${\mu}g \;L^{-1}$ treatments. The observed periods of dead pupa were D32-D34 in control and D33-D37 in 10${\mu}g \;L^{-1}$ treatments. Consequently, due to molting hormone disruption, development of midge was postponed relatively low concentration such as 10 treatments of tebufenozide.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.1
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• pp.59-64
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• 1999

Purpose: The aims of this study are to measure the serum levels of fat soluble vitamins (vitamin A and D) from bile duct ligated rats, and to evaluate the effect of oral bile acids administration to facilitate absorption of fat soluble vitamins. Methods: We measured serum ALT, total bilirubin, vitamin A, and vitamin D of Sprague-Dawley rats 1 week before and 4 weeks after experimental bile duct ligation. Rats were consisted with 3 groups. Group 2 had been fed bile acids and group 3 ursodeoxycholic acid after operation for 4 weeks. Multi-vitamin was given to all groups. Results: 1) Base line (mean value before duct ligation): ALT 74.2 IU, total bilirubin 0.26 mg/dL; vitamin D 13.01 ng/mL vitamin A $0.87\;{\mu}g/mL$, total bile acids $25.16\;{\mu}mol/L$. 2) Four weeks after ligation: ALT 100.7 IU, total bilirubin 2.58 mg/dL; vitamin D 7.89 ng/mL vitamin A $1.37{\mu}g/mL$, total bile acids $278.22\;{\mu}mol/L$. 3) 4 weeks after ligation, each group (group 1, group 2 and group 3) showed vitamin D (7.62, 8.10 and 7.99) ng/mL, vitamin A (1.68, 1.06 and 1.33) ${\mu}g/mL$, total bile acids (233.17, 345.80 and 268.57) ${\mu}mol/L$, which were statistically not significant. Conclusion: Serum level of vitamin A is increased after bile duct ligation although vitamin D is decreased. Oral administration of bile acids does not affect the serum levels of vitamin A and D in bile duct ligated rats.

• Polymer(Korea)
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• v.35 no.1
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• pp.52-59
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• 2011

L-PLA or D-PLA was synthesized in bulk at $140^{\circ}C$ by ring opening polymerization(ROP) of L-lactide or D-lactide as a monomer using tin(II) octoate and lauryl alcohol as a catalyst and an initiator with changing the amounts of catalyst(0.25~1.0 wt%) and initiator(0.l~0.5 wt%). And stereocomplex-PLA was prepared by L-PLA/D-PLA having a wide range of molecular weight(30000~90000 g/mol) and L-PLA/D-PLA blends having different mixing ratio ($X_D$). The melting temperature. thermal degradation temperature and thermal stability of stereocomplex-PLA were higher than those of homopolymers(L-PLA, D-PLA). We supposed that these improvements arose from a strong interaction between L-PLA and D-PLA. The improved mechanical properties and changes in morphology of LPLA/D-PLA blends were compared to those of homopolymers(L-PLA, D-PLA).

• Archives of Pharmacal Research
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• v.12 no.1
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• pp.42-47
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• 1989

From the roots of Puisatiila koreana, three monodesmosides(pulsatilla saponins A, B and D) and two bisdesmosides(pulsatilla saponins F and H) were isolated. The structure of these saponins have been determined as hederagenin 3-O-${\beta}$-L-rhamnopyranosyl($1{\to}2$)- ${\alpha}$-L-arabinopyranoside(A), hederagenin 3-O-${\beta}$-D-glucopyrano syl($1{\to}4$) - ${\alpha}$-L-arabinopyranoside(B), hederagenin 3-O- ${\alpha}$-L-rhamnopyranosyl ($1{\to}2$)-[${\beta}$-D-glucopyranosyl($1{\to}4$]-${\alpha}$-L-arabinopyranoside(D), 3-O-${\alpha}$-L-rhamnopyranosyl($1{\to}2$)-{${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\alpha}$-L-rhamnopyrano syl($1{\to}4$)-${\beta}$-D-glucopyrano syl($1{\to}6$)-${\beta}$-D-glucopyranosyI ester (F) and 3-O-${\alpha}$-L-rhamnopyranosyl($1{\to}2$)-[${\beta}$-D-glucopyranosyl($1{\to}4$)]- ${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\alpha}$-L-lharnnopyranosyl($1{\to}4$)-${\beta}$-D-glucopyranosyl($1{\to}6$)-${\beta}$-D-glucop yranosyl ester(H) on the basis of chemical and spectral studies. Pulsatilla saponin B is the first report of its presence in plants but saponins A, D, F, and H have recently been isolated from the same genus p. cernua.

• Bulletin of the Korean Mathematical Society
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• v.49 no.4
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• pp.767-774
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• 2012

For a positive square-free integer $d$, let $t_d$ and $u_d$ be positive integers such that ${\epsilon}_d=\frac{t_d+u_d{\sqrt{d}}}{\sigma}$ is the fundamental unit of the real quadratic field $\mathbb{Q}(\sqrt{d})$, where ${\sigma}=2$ if $d{\equiv}1$ (mod 4) and ${\sigma}=1$ otherwise For a given positive integer $l$ and a palindromic sequence of positive integers $a_1$, ${\ldots}$, $a_{l-1}$, we define the set $S(l;a_1,{\ldots},a_{l-1})$ := {$d{\in}\mathbb{Z}|d$ > 0, $\sqrt{d}=[a_0,\overline{a_1,{\ldots},2a_0}]$}. We prove that $u_d$ < $d$ for all square-free integer $d{\in}S(l;a_1,{\ldots},a_{l-1})$ with one possible exception and apply it to Ankeny-Artin-Chowla conjecture and Mordell conjecture.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1169-1176
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• 2010

The RF front-end for L1/L2 dual-band Global Positioning System(GPS) receiver is presented in this paper. The RF front-end(down-converter) using low IF architecture consists of a wideband low noise amplifier(LNA), a current mode logic(CML) frequency divider and a I/Q down-conversion mixer with a poly-phase filter for image rejection. The current bleeding technique is used in the LNA and mixer to obtain the high gain and solve the head-room problem. The common drain feedback is adopted for low noise amplifier to achieve the wideband input matching without inductors. The fabricated RF front-end using $0.18{\mu}m$ CMOS process shows a gain of 38 dB for L1 and 41 dB for L2 band. The measured IIP3 is -29 dBm in L1 band and -33 dBm in L2 band, The input return loss is less than -10 dB from 50 MHz to 3 GHz. The measured noise figure(NF) is 3.81 dB for L1 band and 3.71 dB for L2 band. The image rejection ratio is 36.5 dB. The chip size of RF front end is $1.2{\times}1.35mm^2$.

• Journal of Nutrition and Health
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• v.48 no.6
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• pp.476-487
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• 2015

Purpose: This study was conducted to examine the concentration of nutrients in transitional breast milk from Korean lactating mothers and to evaluate daily intakes of their infants based on the Dietary Reference Intakes for Koreans 2010 (KDRIs 2010). Methods: Breast milk samples were collected at 5~15 days postpartum from 100 healthy lactating Korean mothers. Macro- and micro-nutrients, and immunoglobulin (Igs) concentrations in breast milk were analyzed. Results: The mean energy, protein, fat, and carbohydrate concentrations in breast milk were $59.99{\pm}8.01kcal/dL$, $1.47{\pm}0.27g/dL$, $2.88{\pm}0.89g/dL$, and $6.72{\pm}0.22g/dL$. The mean linoleic acid (LA), a-linolenic acid (ALA), arachidonic acid (AA), and docosahexaenoic acid (DHA) concentrations were $181.44{\pm}96.41mg/dL$, $28.15{\pm}8.89mg/dL$, $5.67{\pm}1.86mg/dL$, and $5.74{\pm}2.57mg/dL$. The mean vitamin A, vitamin D, vitamin E, vitamin $B_1$, vitamin $B_2$, vitamin $B_{12}$, and folate concentrations were $2.75{\pm}1.75{\mu}g/dL$, $2.31{\pm}1.12ng/dL$, $0.74{\pm}1.54mg/dL$, $3.02{\pm}1.84mg/dL$, $7.51{\pm}20.96{\mu}g/dL$, $61.78{\pm}26.78{\mu}g/dL$, $63.71{\pm}27.19ng/dL$, and $0.52{\pm}0.26{\mu}g/dL$. The mean concentrations of calcium, iron, potassium, sodium, zinc, and copper were $20.71{\pm}3.34mg/dL$, $0.59{\pm}0.86mg/dL$, $66.71{\pm}10.35mg/dL$, $27.72{\pm}10.16mg/dL$, $0.44{\pm}0.41mg/dL$, and $70.48{\pm}30.41{\mu}g/dL$. The mean IgA and total IgE concentrations were $61.85{\pm}31.97mg/dL$ and $235.00{\pm}93.00IU/dL$. The estimated daily intakes of infants for protein, vitamin D, vitamin E, vitamin $B_2$, vitamin $B_{12}$, iron, potassium, sodium, zinc, and copper were sufficient compared to KDRIs 2010 adjusted by transitory milk intakes. The estimated infants' intakes of energy, fat, carbohydrate, vitamin A, vitamin C, vitamin $B_1$, folate, and calcium did not meet KDRIs 2010 adjusted by transitory milk intakes. Conclusion: In general most estimated nutrient intakes of Korean breast-fed infants in transitory breast milk were sufficient, however some nutrient intakes were not sufficient based on KDRIs 2010. These results warrant conduct of future studies for investigation of important dietary factors associated with nutrients in breast milk to improve the quality of breast milk, which may contribute to understanding nutrition in early life and promoting growth and development of breast-fed infants.