• Journal of the Korean Chemical Society
• /
• v.51 no.2
• /
• pp.165-170
• /
• 2007

In this work, caffeine and some catechin compounds such as +C, EGC and EGCG were extracted from green tea using quercetin molecular imprinted polymers in solid-phase extraction. For synthesis of MIP, quercetin as the templates, MAA as the monomer, EGDMA as the crosslinker and AIBN as the initiator were used. For extraction of caffeine and catechin compounds from green tea, the solid-phase extractions of a load followed by wash and elution procedures were done with water, methanol and methanol:acetic acid=90:10 (vol.%) as the solvents, respectively. HPLC analysis (C18 column, 5 μm, 250×4.6 mm) with the mobile phase of methanol:water=40:60 (vol.%) at a flow rate of 0.5 ml/min was adopted for the quantitative determination. By solid-phase extraction, the resolutions of caffeine and some catechin compounds from green tea were increased. The quercetin-MIP had higher selectivity to +C compounds.

• Textile Coloration and Finishing
• /
• v.13 no.6
• /
• pp.33-33
• /
• 2001

The physical properties and the dyeability of the easily dyeable polyester yarn(EDY) were investigated and compared with those of regular polyester (REG-PET). The EDY, copolymerized with small amount of polyethylene glycol(PEG), showed higher intensity of aliphatic CH peak in IR spectrum, lower density and lower compactness than those of the REG-PET from the analysis of IR, density gradient column and XRD respectively. In the physical properties, the EDY has lowers $T_g,\;T_m$, specific stress and initial modulus, and also has higher strain than that of the REG-PET. The EDY can be dyed under atmospheric pressure and its dyeing rate was faster than REG-PET due to low $T_d$, and this seems to be caused by the increased flexibility of Polymer chain in amorphous region of the EDY due to the copolymerization of PEG.ns being within the experimental error, the average values of lifetim.
$\tau$(t) are taken for further calculations. Rate constants such as Stern-Volmer quenching constants K$_{sv}$, quenching rate parameters k$_q$ and k''$_q$, static quenching constant V and kinetic distance r are determined using the modified Stern-Volmer eq.
tion and sphere of action static quenching model. In order to see whether the reactions are diffusion limited, equations k$_q$ = e$^{-Eq/RT}$ and k''$_q$ = e$^{-Eq/RT}$ are used to determine the values of E$_q$ and E''$_q$, the activati.
energies for collisional quenching and the values of E$_q$ are 14.53, 17.28 and 16.20 kJ mole$^{-1}$ for MPNO1, MPNO2 and 2-PI respectively and the values of E''$_q$ are 14.62 and 17.73 for MPNO1 and MPNO2 respectively. From the magnitudes of various quantities it has.
een concluded that the reactions are diffusion limited and the observed positive deviations in the S-V plot are due to static and dynamic quenching.

• Analytical Science and Technology
• /
• v.6 no.5
• /
• pp.435-442
• /
• 1993

Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.

• KSBB Journal
• /
• v.27 no.3
• /
• pp.151-156
• /
• 2012

Lactic acid is an important product arising from the anaerobic fermentation by lactic acid bacteria (LAB). It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. The poly lactic acid (PLA) is an important material for bio-plastic manufacturing process. For PLA production by new LAB, we screened LAB isolates from shellfish. A total of 28 LAB were isolated from various shellfishes. They were all Gram positive, oxidase and catalase negative. Based on API 50CHL kit, 7 strains among the 28 isolates were identified as Lactobacillus plantarum, 6 strains as Lactobacillus delbrueckii, 5 strains as Leuconostoc mesenteroides, 3 strains as Lactobacillus brevis, 2 strains as Lactococcus lactis, 1 strain as Lactobacillus salivarius, 1 strain as Lactobacillus paracasei, 1 strain as Lactobacillus pentosus, 1 strain as Lactobacillus fermentum and 1 strain as Pediococcus pentosaceu. Also, we examined the amount of total lactic acid produced by these new strains by HPLC analysis with Chiralpak MA column. One strain E-3 from Mytilus edulis was indentified as Lactobacillus plantarum and found to produce 20.0 g/L of D-form lactic acid from 20 g/L of dextrose. Further studies are underway to increase the D-lactic acid production by E-3.

• Korean Journal Plant Pathology
• /
• v.14 no.3
• /
• pp.191-202
• /
• 1998

About 300 actinomycetes were isolated from two forest and one sea-shore soil and tested for inhibitory effects on mycelial growth of six plant pathogenic fungi Magnaporthe grisea, Alternaria mali, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f. sp. cucumerinum, and Rhizoctonia solani. Among 300 actinomycetes tested, only 16 actinomycetes showed the antifungal activity against the test fungi. Isolate NH 50 was selected for production and purification of antifungal antibiotic substances. Actinomycete isolate NH 50 displayed the broad antifungal spectra against 11 plant pathogenic fungi. To identify actinomycete isolate NH 50, cultural characteristics on various agar media, diaminopimelic acid type, and morphological characteristics by scanning electron microscopy were examined. As a result, actinomycete isolate NH 50 was classified as a rare actinomycete that had LL-DAP type and did not produce spores. After incubation of isolate NH 50 in yeast extract-malt extract-dextrose broth, antifungal compound NH-B1 that inhibited mycelial growth of some plant pathogenic fungi was purified from the methanol eluates of XAD-16 resins by a series of purification procedures, i.e., silica gel flash chromatography, C18 flash chromatography, Sephadex LH-20 column chromatography, silica gel medium pressure liquid chromatography (MPLC), C18 MPLC, and high pressure liquid chromatography (HPLC). UV spectrum and 1HNMR spectrum of antifungal compound NH-B1 dissolved in methanol were examined. The antibiotic NH-B1 showed the major peaks at 230 and 271.2nm. Based on the data of 1H-NMR spectrum, NH-B1 was confirmed to be an extremely complex polymer of sugars called polysaccharides. The antibiotic NH-B1 showed strong antifungal activity against Alternaria solani and Cercospora kikuchi, but weak activity against M. grisea.

• Advances in concrete construction
• /
• v.8 no.4
• /
• pp.335-349
• /
• 2019

To investigate the axial compressive performance of the recycled aggregate concrete (RAC) filled glass fiber reinforced polymer (GFRP) tube and profile steel composite columns, static loading tests were carried out on 18 specimens under axial loads in this study, including 7 RAC filled GFRP tube columns and 11 RAC filled GFRP tube-profile steel composite columns. The design parameters include recycled coarse aggregate (RCA) replacement percentage, profile steel ratio, slenderness ratio and RAC strength. The failure process, failure modes, axial stress-strain curves, strain development and axial bearing capacity of all specimens were mainly analyzed in detail. The experimental results show that the GFRP tube had strong restraint ability to RAC material and the profile steel could improve the axial compressive performance of the columns. The failure modes of the columns can be summarized as follow: the profile steel in the composite columns yielded first, then the internal RAC material was crushed, and finally the fiberglass of the external GFRP tube was seriously torn, resulting in the final failure of columns. The axial bearing capacity of the columns decreased with the increase of RCA replacement percentage and the maximum decreasing amplitude was 11.10%. In addition, the slenderness ratio had an adverse effect on the axial bearing capacity of the columns. However, the strength of the RAC material could effectively improve the axial bearing capacity of the columns, but their deformability decreased. In addition, the increasing profile steel ratio contributed to the axial compressive capacity of the composite columns. Based on the above analysis, a formula for calculating the bearing capacity of composite columns under axial compression load is proposed, and the adverse effects of slenderness ratio and RCA replacement percentage are considered.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.1
• /
• pp.106-111
• /
• 1994

2-iminothiolane is known to bind $NH_2$ group of lysine in the protein and deliver SH group, which can be used to label protein with $^{99m}Tc$. In this study, we looked for the best reaction condition in which 2-iminothiolane is conjugated to human polyclonal IgG and labeling condition with $^{99m}Tc$-glucoheptonate. Labeling yield was measured with TSK G4000SW column and HPLC or precipitation with 10% TCA (trichloroacetic acid) and 1% HSA. In vivo distribution was investigated with Staphylococcal abscess bearing rats. With decreasing glucoheptonate, the labeling yield decreased. Without 2-iminothiolane, $^{99m}Tc$-glucoheptonate was bound to IgG, which seemed to be direct labeling. With increasing 2-iminothiolane upto 20 times higher than IgG, the labeling yield increased, and plateau was seen with higher molar excess of 2-iminothiolane. Polymer formation was not observed. The pH for the conjugation of 2-iminothiolane and IgG was best around 6.4. $^{99m}Tc$-2-iminothiolane-IgG showed faster blood clearance, higher renal activity and lower hepatic and splenic activity than $^{99m}Tc$-DTPA-IgG. The biodistribution of $^{99m}Tc$-2-iminothiolane-IgG with higher molar excess of 2-iminothiolane was not different from that with lower molar excess. Labeling antibodies with $^{99m}Tc$ using 2-iminothiolane can afford a possible route to simple labeling and wide clinical use of the immunoscintigraphy.

• Applied Biological Chemistry
• /
• v.35 no.1
• /
• pp.36-41
• /
• 1992

Several commercial cottonseed, corn and rapeseed oils were stored at $60^{\circ}C\;and\;70^{\circ}C$ with daily exposure of fluorescent light for 12 hours and evaluated their rancidity by headspace gas chromatographic analysis of pentanal and hexanal. The data of gas chromatographic analysis was compared with organoleptic flavor evaluation. For headspace gas chromatographic analysis, the volatile compounds were recovered by porous polymer trap and flushed into a fused silica capillary column at $250^{\circ}C$. Twenty-three GC peaks were identified on the basis of relative retention time of reference compounds and gas chromatography-mass spectrometry. The results showed that the contents of pentanal and hexanal were linearly increased during storage. A very simple linear relationship was found between organoleptic flavor scores and amounts of two volatile compounds with very high correlation coefficient. This results suggested the possible implication of pentanal and hexanal as an quality index for rancidity evaluation of cottonseed, corn and rapeseed oils.

• Analytical Science and Technology
• /
• v.11 no.6
• /
• pp.478-484
• /
• 1998

Distribution of polyphenolic compounds in oak tree (Quercus acutissima, three years old) collected from Forest Research Institute located in Kwang Leung, Kyeonggi-do, Korea, was investigated using chromatographic studies. Total 25 polyphenolic fractions were separated from an oak tree, of which 15, 11, 7, 7, and 4 were in leaf, stem, root, bark, and seed, respectively. Catechins are predominant compounds in the polyphenols and some flavonoids were also identified. Distribution of polyphenols was relatively different in each part. Polyphenols in all of the part studied, except leaf where polymer was not detected, were existed as polymeric, oligomeric, and monomeric forms. Relative contents of total polyphenols in Quercus acutissima were the highest in bark, followed by root, leaf, acorn, and stem. Monomeric polyphenols were the predominant compounds present in all of the part of the oak tree.

• The Journal of Korean Medicine
• /
• v.23 no.1
• /
• pp.83-91
• /
• 2002

Objectives : In this study, water extracts from Coix lachryma-jobi Linne var. mayuen Stapf. were investigated for their effects on insulin-like action and glucose uptake in 3T3-Ll cells. Methods : We examined the effects of insulin-like action on the differentiation of 3T3-Ll fibroblasts. The Coicis Semen was treated with hot water and the extract was freeze-dried. The hot water extract was chromatographed on nonionic polymer resin (Amberlite XAD-4, Sigma) with distilled water (Fr. 1), 20% (Fr. 2), 40% (Fr. 3), 60% (Fr. 4), 80% (Fr. 5), and 100% EtOH (Fr. 6), successively. Results : Total extract of Coicis Semen was fractionated into 0 to 100% MeOH with Amberlite XDA-4 column. Treatment of cells with $10{\;}\mu\textrm{g}/ml$ of total extracts of Coicis Semen significantly increased the differentiation (p<0.05). At $1{\;}\mu\textrm{g}/ml$ level of insulin, the differentiation was accelerated (p<0.01). The effect of extracts plus insulin on the differentiation was greater than that of insulin alone. In 3T3-Ll adipocytes, glucose uptake was higher by 2.7 times with 5 uM of total extract in low dosage of insulin (3 ng/ml) than without total extract. 5 and 50 uM of water and 40% MeOH fractions increased glucose uptake by 3.5 times in 3T3-Ll adipocytes (p<0.00l). Conclusions : Coicis Semen contains compounds which playa role of insulin-like action and insulin sensitizer.