Earticle

Chiral crown ethers are synthetic macrocyclic polyethers that bind protonated chiral primary amines with high selectivity and affinity. They have been widely used to separate or distinguish the enantiomers of chiral compounds containing a primary amino moiety by high-performance liquid chromatography, capillary electrophoresis, and NMR spectroscopy. In this paper, two important chiral crown ethers including chiral binaphthyl unit and (18-crown-6)-2,3,11,12- tetracarboxylic acid as chiral selectors are focused. And several chiral resolution techniques and their applications in chirotechnology using these chiral crown ethers with related chiral recognition mechanism studies are reviewed. Especially, it was shown that the commercially available HPLC columns based on (18-crown-6)-2,3,11,12-tetracarboxylic acid have been developed and successfully applied for the resolution of various primary amino compounds including amino acids.

Emulsions are mixture of immiscible liquids in which one is dispersed in all over the other. They have been applied to many applications including cosmetics, foods, drug delivery system (DDS), fine chemicals, and chemical separations. Especially, emulsion technology is one of the most useful technique to formulate cosmetics such as eye cream, foundation, and foam cleansing. In general, the emulsions can be generated by mechanical agitation of two immiscible fluids. However, the emulsions obtained by conventional method have limited in stability, monodispersity, and complicate process. We describe here preparation techniques of representative cosmetic emulsions such as liposome, liquid crystal emulsion, nanoemulsion, multiple emulsion, and pickering emulsion. Furthermore, various factors which can control the physical properties of each cosmetic emulsions are briefly discussed.

Synthetic plastics are important in many branches of industry. Although synthetic plastics provide numerous benefits, they also cause a significant environmental pollution problem because of their non-readily-biodegradability. Biodegradation may provide solution to the problem, but not enough is known about the biodegradation mechanisms of synthetic plastics. This review has been written to provide an overview of the current state of synthetic plastics (polyethylene, polyurethane, nylon, polyvinyl alcohol) biodegradation. Several biodegradation mechanisms of a few selected synthetic plastics are also presented.

In this study, the effect of gamma irradiation on the microbial contamination and biological activities of tuna cooking juices was investigated. Tuna cooking juice was by-produced during the canning processing, and had various functional components. But, it was shown that the tuna cooking juice was seriously contaminated. Gamma irradiation effectively reduced the microbial population in tuna cooking juice. Also, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, tyrosinse inhibitory activity, and ACE inhibitory activity of tuna cooking juices were all increased as a result of gamma irradiation. These results suggest that wasted tuna cooking juices can be used as a functional component in the food and cosmetic industries if the irradiation technology were applied.

Whole plants of Zostera asiatica were extracted twice with acetone/methylene chloride (A+M) and methanol (MeOH) in turn. The combined crude extracts were evaporated in vacuo and then the residue was partitioned between water and methylene chloride. The aqueous layer was fractionated into H2O and n-butanol and then the organic layer was also fractionated into 85% aq. MeOH and n-hexane, successively. The crude extracts and their solvent fractions were evaluated for their inhibitory effect on growth of human cancer cells AGS, HT-29, MCF-7, and HT-1080 cells by MTT reduction assay. Among samples tested, 85% aq. MeOH and n-hexane fractions showed strong cytotoxic effect against AGS, HT-29, and MCF-7 cells. On the other hand, for HT-1080 cell, 85% aq. MeOH fraction exhibited the strongest cytotoxic effect.

Comparative liquid chromatographic enantiomer separation of α-amino acids, their esters and primary amino compounds was performed using two chiral stationary phases (CSPs) prepared by covalently bonding (+)-(18-crown-6)- 2,3,11,12-tetracarboxylic acid (18-C-6-TA) of the same chiral selector. In general, the separation factors and resolution factors for these analytes on CSP 1 were greater than on CSP 2, while these capacity factors on CSP 2 were quite greater than on CSP 1. Except for leucine methyl ester and phenylalanine methyl ester, the elution orders of all analytes including α- amino α-alkyl acids and phenylglycine alkyl esters on CSP 1 are identical to those on CSP 2. This study showed that different connecting structures for these two CSPs might influence their ability to resolve the analytes depending on their structures related to the chiral recognition mechanism.

In this study, zein microparticles and drug-loaded zein microparticles were prepared using supercritical ASES technique. The effects of operating parameters on particle size and morphology were investigated. ASES-processed zein microparticles consisted of agglomerates of very fine unit particles. As temperature increased, the size of unit particles increased and their morphology became more spherical. The addition of water to the solvents for zein resulted in the formation of more spherical microparticles. The release characteristics of drug-loaded zein microparticles were also studied.

The ash content, mineral composition, total phenolics, antioxidant capacity, and neuroprotective effect of the antlers of deer fed with herb-incorporated feedstuff (HFS) or normal feedstuff (NFS) were comparatively evaluated. The contents of ash and mineral of the antler of deer fed with HFS were significantly lower than its counterpart. The ash and mineral contents of deer antlers decreased generally from the upper section toward the tip section. The ratios of Ca/ash, Ca/P, and Ca/Fe of antler of deer fed with HFS were lower than those of antler of deer fed with NFS. Antlers of deer fed with HFS had higher total phenolics, nitrite scavenging capacity, and antioxidant capacity than those of deer fed with NFS. Antlers of deer fed with HFS or NFS showed in vitro neuronal protection of PC-12 cells against oxidative stress in a dosedependent manner, where antler of deer fed with HFS generally had higher cellular viability than NFS. These results above suggest that the incorporation of the medicinal herbal complex into feedstuff may improve the biological effects of deer antlers.

In this study we investigated the effect of temperature on the two-stage fermentation of Makgeolli using uncooked germinated black rice. The fermentation processes were conducted at 15℃ for three weeks and 25℃ for 7 days. The pH of Makgeolli at 25℃ increased from pH3.0 to pH 4.2, which was consistent with that at 15℃. In contrast total acidity of Makgeolli at 15℃ was about half of that at 25℃ (0.36% and 0.59%, respectively). By the 7 days-fermentation at 25℃, 11% of alcohol was produced, whereas three weeks were required for the same alcohol production at 15℃. In the case of sugar contents, the amounts of total glucose-equivalent reducing sugars and glucose increased at the end of the fermentation at 25℃ up to 2.25 mg/mL and 3.4 mM, respectively, whereas those at 15℃ were maintained at very low levels (0.18 mg/mL and 0.1 mM, respectively). Such limited supplement of sugars at 15℃ seemed to affect metabolism of yeast, resulting in different composition of organic acid. At 25℃, citric acid that was 73.4 ppm at the initial fermentation was consumed completely, whereas 20 ppm of citiric acid was remained at 15℃. In addition, acetic acid and lactic acid in Makgealli at 15℃ were 53% and 14% of those at 25℃.

The gene encoding Thermus thermophilus HJ6 laccase (Tt-laccase) was cloned, sequenced, and comprised of 1,389 nucleotides encoding a protein (462 amino acids) with a predicted molecular mass of 51,049 Da. The deduced amino acid sequence of Tt-laccase showed 99.7% and 44.3% identities to the Thermus thermophilus HB27 laccase and Synechococcus sp. RS9917 laccase, respectively. Tt-laccase gene was expressed as a fusion protein with six histidine residues in E. coli Rosetta-gami (DE3) cells, and the recombinant protein was purified to homogeneity. UV-Vis spectrum analysis revealed that the enzyme has copper atoms, a type I Cu(II) and a type III binuclear Cu(II). The optimum pH for the oxidation of guaiacol was 5.0 and the optimum temperature was 90℃ The half-life of heat inactivation was about 120 min at 90℃ The enzyme reaction was inhibited by sodium azide, L-cystein, EDTA, dithiothreitol, tropolone, and kojic acid. The enzyme oxidized various known laccase substrates, its lowest Km value being for 4-hydroxyindole, highest kcat value for syringaldazine, and highest kcat/Km for guaiacol.

The purpose of this study was to determine optimum value of aeration rate for the cultivation of Chlorella sp. under illumination of red light emitting diode. The aeration rates varied from 0 to 2.4 vvm under the illumination of 4,400 lux of red light emitting diode. The highest specific growth rate of 1.51 day-1 was obtained at the aeration of 0.7 vvm and lower specific growth rates were obtained for other aeration tests. Furthermore, the highest biomass concentration (1.02 g/L) was also obtained at the aeration of 0.7 vvm. Therefore, aeration of 0.7 vvm was determined to be the optimum aeration rate for the cultivation of Chlorella sp. under red light emitting diode.

Microbially induced calcite precipitation (MICP) has been explored for protection and consolidation of construction materials such as concrete. In this study, we isolated 54 calcite forming bacteria from concrete pavement and selected 5 isolates which showed high specific urease activity. Also response of the 5 strains against various environmental stresses was examined. BC 4 and BC 5 showed 35% and 26% viability at heat stress (50℃), respectively. BC 1 and BC 4 maintained 60.4% and 70.4% viability upon osmotic stress (1 M NaCl), respectively. Among the 5 isolates BC 4 had the highest viability upon alkaline stress (pH 10).