• Macromolecular Research
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• v.15 no.4
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• pp.385-391
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• 2007

Block copolymer micelles are generally formed via the self-assembly of amphiphilic block copolymers in an aqueous medium. The hydrophilic and hydrophobic blocks form shell and core micelles, respectively. The block copolymers of methoxy poly(ethylene glycol) (MPEG)-b-poly(2-diisopropylamino)ethyl methacrylate (PDPA) were synthesized via atom transfer radical polymerization, with the macro initiator synthesized by the coupling of 2-bromoisobutyryl bromide with MPEG in the presence of a triethyl amine base catalyst. The atom transfer radical polymerization of 2-diisopropylamino)ethyl methacrylate was performed in conjunction with an N,N,N',N",N"-pentamethyl-diethylenetriamine/copper bromide catalyst system, in DMF, at $70^{\circ}C$. The pH induced micellization/demicellization was studied using fluorescence, with a pyrene probe. Furthermore, the pH dependent micellization was confirmed using the microviscosity method, with a dipyme fluorescence probe. The pH dependant micelle size distribution was studied using dynamic light scattering. The characterization of the synthesized polymers was established using gel permeation chromatography and from the $^1H-nuclear$ magnetic resonance spectroscopy.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4311-4317
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in the field of cancer therapy and biologically synthesized gold nanoparticles are known to have a wide range of medical applications. Materials and Methods: Gold nanoparticles (GNPs) were biosynthesized with an aqueous extract of the red alga Corallina officinalis, used as a reducing and stabilizing agent. GNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FT-IR) spectroscopy and tested for cytotoxic activity against human breast cancer (MCF-7) cells cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, considering their cytotoxicty and effects on cellular DNA. Results: The biosynthesized GNPs were $14.6{\pm}1nm$ in diameter. FT-IR analysis showed that the hydroxyl functional group from polyphenols and carbonyl group from proteins could assist in formation and stabilization. The GNPs showed potent cytotoxic activity against MCF-7 cells, causing necrosis at high concentrations while lower concentrations were without effect as indicated by DNA fragmentation assay. Conclusions: The antitumor activity of the biosynthesized GNPs from the red alga Corallina officinalis against human breast cancer cells may be due to the cytotoxic effects of the gold nanoparticles and the polyphenolcontent of the algal extract.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2293-2298
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• 2007

In this study, a dithizone extraction technique involving purge & trap GC-MS was developed for the determination of methylmercury in biological samples, especially blood and fish. After alkaline digestion, methylmercury in biological samples was extracted into dithizone and back-extracted into aqueous sulfide solution. The extracted methylmercury was converted to the volatile ethyl derivative, purged and trapped onto a solid-phase collection medium, and then introduced into the GC-MS system. The determined MDLs of the established method were 0.9 ng·g?1 for biological samples and its accuracy and precision were found to be 93% and 3.8%, respectively. The method was validated by analysis of CRMs such as SRM 966, BCR 463 and IAEA 407 and all analytical results were within certified ranges with average RSDs of less than 6%. The analytical results of field-sampled fish also showed that the method can be successfully used as an alternative for commonly used distillation method followed by GC-CVAFS detection.

• KSBB Journal
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• v.9 no.1
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• pp.85-90
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• 1994

The Gellan-type polysaccharide produced by Pseudomonas elodea(ATCC 31461) is one of the new heteropolysaccharides, having useful properties as gelling, suspending, stabilizing, emulsifying and binding agents in aqueous systems. Medium compositions for growth stage and production stage are improved. The problems of low cell concentration and poor productivity in highly viscous fermentation were attributed to inadequate mixing accompanied by insufficient oxygen transfer. During continuous culture, cell growth and polysaccharide production were greatly affected by the apparent viscosity, and they showed oscillation behavior, i.e. as the product concentration increases, cell concentration decreases. With improved culture conditions, the productivity of continuous culture increased up to 0.6g/$\ell$/hr(6-fold that of batch culture ) at dilution rate, D=$0.14hr^{-1}$.

• Herbal Formula Science
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• v.14 no.2
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• pp.86-96
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• 2006

Objectives : This study wad designed to elucidate the short term effect of Rossa rugosae Radix on proliferation, differentiation and maturation of 3T3-L1 Preadipocyte. Methods : 3T3-L1 preadipocytes obtained from Korean Cell line Bank were cultured in a Dulbecco's modified eagle medium(DMED) culture colution containing 10% fetal bovine serum(FBS) and various concentration of aqueous extract of Rossa rugosae Radix on proliferation, differentiation and maturation of 3T3-L1 preadipocytes were investigate after treatment for 24 hours b measuring MTT, Oil Red O and latate dehydrogenase activity.. Results : The Rossa rugosae Radix extract inhibited significantly the proliferation of 3T3-L1 preadipocytes and tended to increase latate dehydrogenase activity in the media of differentiated 3T3-L1 preadipocytes & matured 3T3-L1 preadipocytes. the extract also inhibit the lipid accumulation of differentiated and maturaion of 3T3-L1 preadipocytes, suggesting that Rossa rugosae Radix has anti-obesity effect: however further in vivo study is needed to demonstrate its pharmacological effects.

• Clean Technology
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• v.11 no.1
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• pp.51-56
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• 2005

In this paper we prepared dextrin dialdehyde (DAS) of a different oxidation ratio (aldehyde content) and examined their properties and discussed their tanning mechanism. DAS was produced by reacting dextrin in aqueous medium with periodate ion used in a molar ratio between periodate and glucose of 0.3 to 1.0 at a temperature of 20 to $45^{\circ}C$. Since DAS reacts with amino group, DAS may have tanning property of aldehyde tanning agent (formaldehyde, glutaraldehyde).

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.172-178
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• 1992

The graft copolymerization of acrylonitrile(AN) onto chitosan film by using $F^{3+}(FeCl_3{\cdot}6H_2O)$ as a photosensitizer in an aqueous medium was carried out under ultraviolet(UV) irradiation. The grafted copolymer was identified by using IR spectroscopy and scanning electron microscope. The effects of various polymerization parameters involving monomer concentration, photosensitizer concentration, polymerization time and polymerization temperature were investigated. As monomer concentration and photosensitizer concentration were increased, the percent grafting was increased up to limiting value. And also the percent grafting was found to increase by increasing the polymerization time and temperature.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.61-72
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• 2014

Study on effluent organic matter (EfOM) characteristic and removal efficiency is required, because EfOM is important in regard to the stability of effluents reuse, quality issues of artificial recharge and water conservation of aqueous system. UV technology is widely used in wastewater treatment. Many reports have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on EfOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics. The high intensity of pulsed UV would mineralize EfOM itself as well as change the characteristics of EfOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of EfOM. The objective of this study is to investigate the effect on EfOM, chlorine residual, and chlorinated DBPs formation with low pressure and pulsed UV treatment. The removal of organic matter through low pressure UV treatment is insignificant effect. Pulsed UV treatment effectively removes/transforms EfOM. As a result, the chlorine consumption is changed and chlorine DBPs formation is decreased. However, excessive UV treatment caused problems of increasing chlorine consumption and generating unknown by-products.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.201-204
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• 2002

The gellan was extracellular polysaccharide produced by Pseudomonas elodea A TCC 31461 at aerobic condition. Gellan provides various functionalities such as gelling, suspending, stabilizing, emulsifying and binding properties in aqueous systems. In this study, the effect of pH on the cell growth and the gellan production were evaluated in shake- flasks and in 5 ${\ell}$ batch fermentor. In the shake-flasks culture, maximum gellan production was obtained with 1.66g/ ${\ell}$ when initial pH was 7.0. The batch fermentation was performed in the medium pH control ranged pH 5.5-8.5. The maximum gellan production of 1.97g/l was obtained with constant pH 6.0.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.321-324
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• 2002

In situ recovery of recombinant human granulocyte-macrophage colony stimulating factor (hGM-CSF) was performed in transgenic Nicotiana tabacum cell suspension cultures. Aqueous two-phase systems (ATPS) were used to utilize its biocompatibility. Transgenic plant cells could be grown up to 15.7 g/L in normal medium and 18.6 g/L in ATPS composed of 6% (w/w) polyethylene glycol (PEG) 20,000 and 10% (w/w) dextran 2,000,000. It was proved that the A TPS was not harmful to cell growth. In addition, It is expected to recover hGM-CSF simultaneously with cell growth. Using this method, maximum hGM-CSF concentration at 1.64 ng/mL was obtained on day 3.