• The Korean Journal of Nuclear Medicine
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• v.31 no.4
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• pp.440-451
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• 1997

This study was designed to prospect the $^{111}In$-labelled paclitaxel as tumor imaging agent. In order to provide a taxol molecule with a functional group which is able to chelate In-111, taxol-DTPA conjugate and 2'-hemisuccinyltaxol were synthesized by esterification of taxol at C-2'on C-13 carbon with DTPA anhydride and succinic anhydride, respectively. Synthesis yield of the taxol derivatives was 34% for taxol-DTPA and 80% for 2'-hemisuccinyltaxol. Cytotoxicity of the taxol derivatives were measured by MTT method toward cell lines HT29, B16, P388, and CT26. The cytotoxic activities of the taxol derivatives were maintained, although less active than taxol. Radiolabelling of the taxol derivatives were proceeded directly with $^{111}InCl_3$ or indirectly with $^{111}In$-citrate(ligand-exchange method). The ligand-exchange method was not suitable because some precipitates appeared during the reaction. On the contrary, by direct radiolabelling method, we were able to obtain taxol-DTPA-$^{111}In$ in 100% radiochemical yield. However, 2'-hemisuccinyltaxol was not labelled by both methods. Yield and radiochemical purity of the radiolabelled com-pound were determined by HPLC, paper chromatography and instant thin layer chromatography. Taxol-DTPA-$^{111}In$ was characterized to be hydrophilic by lipophilicity test, and nearly non-adhesive to HT29, B16, P388, and CT26 by cell binding affinity test. Binding affinity of the taxol-DTPA-$^{111}In$ complex to serum proteins was also examined by protein precipitation with 30% trichloroacetic acid. The results showed that 30% of the taxol-DTPA-$^{111}In$ complex binds with serum proteins.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1063-1067
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• 2007

The Bcl-2 family proteins play critical roles in regulation of apoptosis, and the balanced interaction of pro- and anti-death members is a key factor in determining the cell fate. Noxa, a BH3-only Bcl-2-family member, has been originally identified as a target gene of p53. To understand the mechanism by which human Noxa (hNoxa) regulates the cell death, we screened the hNoxa binding partner using the yeast two hybrid screening and found that anti-death protein Mcl-1 binds to hNoxa. The binding of hNoxa to Mcl-1 was confirmed by immunoprecipitation in human colon cancer cell line HCT 116 cells. Mcl-1 significantly inhibited the hNoxa-induced cell death in HCT 116 cells. During the cell death induced by hNoxa, Mcl-1 protein was degraded. Its degradation was inhibited by z-VAD-fmk, a pancaspase inhibitor, suggesting caspase is responsible for Mcl-1 degradation in response to hNoxa. Together, the results indicate that hNoxa binds to Mcl-1 that is degraded by cas-pases during hNoxa-induced cell death.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.1-21
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• 2011

This review describes several kinds of emulsification methods for nanoemulsions and the application of nanoemulsions. Nanoemulsion droplet sizes fall typically in the range of 20 ~200 nm and show narrow size distributions. Although most of the publications on either oil-in-water (O/W) or water-in-oil (W/O) nanoemulsions have reported their formation by dispersion or high-energy emulsification methods, an increased interest is observed in the study of nano-emulsion formation by condensation or low-energy emulsification methods based on the phase transitions that take place during the emulsification process. Phase behaviour studies have shown that the size of the droplets is governed by the surfactant phase structure (bicontinuous microemulsion or lamellar) at the inversion point induced by either temperature or composition. Studies on nanoemulsion formation by the phase inversion temperature (PIT) method have shown a relation between minimum droplet size and complete solubilization of the oil in a microemulsion bicontinuous phase independently of whether the initial phase equilibrium is single or multiphase. Due to their small droplet size nanoemulsions possess stability against sedimentation or creaming with Ostwald ripening forming the main mechanism of nanoemulsion breakdown. An application of nanoemulsions is the preparation of nanoparticles using a polymerizable monomer as the disperse phase where nanoemulsion droplets act as nanoreactors, cosmetics and controlled drug delivery. In this review, we mainly focus on the cosmetics.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.49-57
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• 1997

Naturally-occurring iron minerals, goethite and magnetite, were used to catalyze hydrogen peroxide and initiate Fenton-like oxidation of silica sand contaminated with diesel, kerosene in batch systems. Reaction conditions were investigated by varying H$_2$0$_2$concentration(0%, 1%, 15%), initial contaminant concentration(0.2, 0.5, 1.0g diesel and kerosene/kg soil), and iron minerals(1, 5wt% magnetite or goethite). Contaminant degradations in silica sand-iron mineral-$H_2O$$_2$ systems were identified by determining total petroleum hydrocarbon(TPH) concentration. In case of silica sand contaminated with diesel(1g contaminan/kg soil with 5wt% magnetite) addition of 0%, 1%, 15% of $H_2O$$_2$showed 0%, 25%, and 60% of TPH reduction in 8 days, respectively When the mineral contents were varied from 1 to 5wt%, removal of contaminants increased by 16% for magnetite and 13.1% for goethite. The results from system contaminated by kerosene were similar to those of the diesel. Reaction of magnetite system was more aggressive than that of goethite system due to dissolution of iron and presence of iron(II) and iron(III); however, dissolved iron precipitated on the surface of iron mineral and seemed to cause reducing electron transfer activity on the surface and quenching $H_2$$O_2$. The system used goethite has better treatment efficiency due to less $H_2$$O_2$ consumption. Results of this study showed possible application of catalyzed $H_2$$O_2$ system to petroleum contaminated site without addition of iron source since natural soils generally contain iron minerals such as magnetite and goethite.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.295-301
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• 2010

Recent studies demonstrated that the combination of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) resulted in the formation of a precipitate, para-chloroaniline (PCA). Alexdidine (ALX) is a kind of biguanides like CHX, and has stronger detoxification effect against the bacterial virulence factors such as lipoteichoic acid and lipopolysacchardide compared with CHX. The purpose of this study was to determine whether PCA was formed after chemical interaction between ALX and NaOCl using mass spectrometry. Mass spectrometry was performed for the mixture of five different concentrations of ALX (1, 0.5, 0.25, 0.125, 0.0625%) and 4% NaOCl. Results showed that the peak of PCA was not detected in mixed solutions of ALX and NaOCl in mass spectrometry analysis. The color of mixed solution of ALX and NaOCl after chemical interaction was light yellow to white, but there wasn't any precipitate found.

• Resources Recycling
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• v.25 no.2
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• pp.33-41
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• 2016

A scale up tests (380 kg/day) using a continuous solvent extraction and electro-winning system was carried out to separate and recover cobalt from a solution containing 1.91 g/L Co and 14.65 g/L Ni. The solution was obtained during a process including solvent extraction and precipitation stages for removal of Cu and Fe from a synthetic sulfuric acid solution of manganese nodule matte. The optimal condition for solvent extraction was : solvent concentration of 0.22M Na-Cyanex 272 (45% saponified with NaOH) and O:A phase ratios of 1:1.5, 10:1 and 1.5:1 used in extraction, scrubbing and stripping stages, respectively. The extraction and stripping efficiencies were found to be 99.8% and 99.88%, respectively. The stripped solution contained 40.27 g/L Co with 4 ppm Ni. Cobalt metal of 99.963% purity was yielded with current efficiency of 67% and current density of $0.563A/dm^2$ during the electro-winning process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.4
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• pp.32-39
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• 1986

A strain of Aspergillus niger CAD 1 which produces considerable amount of beta-galactosidase was selected from extracellular beta-galctaosidase producing fungi isolated from soil. Optimal conditions for the enzyme from Aspergillus niger CAD 1 were the growth in wheat bran supplemented with 0.5% skim milk powder at $30^{\circ}C$ for 72 hrs. The crude enzyme was purified 1,387 fold through DEAE-cellulosc and Sephadex G-100 chromatographr and its recovery was 6.2%, The optimal pH and temperature for the purified enzyme were pH 4.5 ana $45^{\circ}C$, respectively. The Km and Vmax on ONPG were $3.57{\times}10^3M$ and 33.0 unit/mg protein, whereas those on lacose were $83.3{\times}10^3M$and 15.33 unit/mg protein, respectively, The activation energy for the enzyme was 9,900 cal/mol and the enzyme had no metal ion requirement for its activity and stability. The hydrolysis of lactose in skim milk, 4.8% lactose solution and acidic whey were 65%, 70% and 78% after 10 hrs incubation at $45^{\circ}C$, when 182 units of the enzyme were used 50ml of the substrate solutions.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.243-248
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• 2016

RNase E (Rne) is an essential enzyme involved in the processing and degradation of a large portion of RNAs in Escherichia coli. The enzymatic activity of RNase E is controlled by regulators of ribonuclease activity, namely, RraA and RraB. Gram-positive bacterium Streptomyces coelicolor also contains homologs of Rne and RraA, designated as RNase ES (Rns), RraAS1, and RraAS2. In the present study, we investigated the effect of S. coelicolor RraAS1 on the ribonucleolytic activity of RNase E in E. coli. Coexpression of RraAS1 with Rne resulted in the decreased levels of rpsO, ftsZ, and rnhB mRNAs, which are RNase E substrates, and augmented the toxic effect of Rne overexpression on cell growth. These in vivo effects appeared to be induced by the binding of RraAS1 to Rne, as indicated by the results of co-immunoprecipitation analysis. These results suggested that RraAS1 induces ribonucleolytic activity of RNase E in E. coli.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.129-134
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• 1995

With a view to utilizing effectively fish skin wasted from marine manufactory, an extracted dover sole skin gelatin was fractionated by further ethanol fractional precipitation method, and then the functional and physicochemical properties for the modified gelatin were determined. Ethanol was added to the concentration of 30% in an extracted dover sole skin gelatin solution, and then the mixture was left to stand at $0^{\circ}C$ for 12 hours. Finally, the precipitates were dried by hot-air$(40^{\circ}C)$ blast. The yellowfin sole skin gelatin prepared by further ethanol fractional precipitation has 223.0 g in gel strength, $17.7^{\circ}C$ in the melting point, and $12.0^{\circ}C$ in the gelling point. The physicochemical properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol adding, whereas inferior to those of animal skin gelatin. The functional properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol adding, and were more similar to animal skin gelatin. It may be concluded, from these results, that the dover sole skin gelatin prepared by further ethanol fractional precipitation can be effectively utilized as a human food by improving the functional properties.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.381-391
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• 2011

Weathering can reduce rock strength and eventually affect the structural stability of a rock mass, which is important in the field of engineering geology. Several methods have been developed to evaluate the degree of weathering, including the chemical weathering index. In this study, we analyzed the weathering degree and characteristics of microtextures and pores in crystalline rocks (gneiss and granites) based on petrographic observations, the chemical weathering index, mineralogy by XRD, microtextural analysis by SEM/EDS, measurements of pore size and surface area by the BET method, and microporosity by X-ray CT. The formation of secondary minerals and microtexture in gneiss and granitic rocks are assumed to be affected by complex processes such as dissolution, precipitation, and fracturing. Hence, it is clear that some chemical weathering indices that are based solely on whole-rock chemistry (e.g., CIA and CWI) are unable to provide reliable assessments of the degree of weathering. Great care is needed to evaluate the degree of chemical weathering, including an understanding of the mineralogy and microtexture of the rock mass, as well as the characteristics of micropores.