• Journal of Pharmaceutical Investigation
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• v.40 no.6
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• pp.357-362
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• 2010

To enhance therapeutic effects of insulin-sensitizing adipokine, ADN gene and potent agonists, rosiglitazone for the $PPAR{\gamma}$, cationic liposomes as non-viral vectors were formulated. The particle size and zeta potential of drug loaded and unloaded cationic liposomes were investigated. The complex formation between cationic liposomes and negatively charged plasmid DNA was confirmed and the protection from DNase was observed. In vitro transfection was investigated in HepG2, HeLa, and HEK293 cells by mRNA expression of ADN. Encapsulation efficacy of rosiglitazone-loaded liposomes was determined by UV detection. Particle sizes of cationic liposomes were in the range of 110-170 nm and those of rosiglitazone-loaded cationic liposomes were in the range of 130-180 nm, respectively. Gel retardation of complexes indicated that the complex was formed at weight ratios of cationic lipid to plasmid DNA higher than 20:1. Both complexes protected plasmid DNA from DNase either drug free or drug loading. Encapsulation efficiency of rosiglitazone-loaded emulsion was increased by drug dose. The mRNA expression levels of ADN were dose-dependently increased in cells transfected with plasmid DNA. Therefore, cationic liposomes could be potential co-delivery system for drug and gene.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.246-251
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• 2013

With -$OCH_2CO$- as a linker, a non ${\beta}$-substituted cationic bisporphyrin (4a) and a ${\beta}$-substituted cationic bisporphyrin (4b) were prepared through methylation of the intermediate which was obtained from ${\beta}$-amino-5,10,15,20-tetra (4-cyanophenyl) porphyrin or 5-hydroxylphenyl-10,15,20-tris(4-cyanophenyl) reacting with 5-hydroxy-10,15,20-trispyridinylporphyrin. Their structures were confirmed by $^1H$ NMR, IR, UV-vis, MS and elemental analysis. DNA photocleavage ability and the singlet oxygen ability of those cationic bisporphyrins were investigated. DNA photocleavage activity of ${\beta}$-substituted cationic bisporphyrin was significantly weaker than that of $H_2TMPyP$, but similar to that of non ${\beta}$-substituted cationic bisporphyrin. While 4a and 4b showed substantial photocleavage activities toward DNA, with 68% and 66% observed at 10 ${\mu}M$. The assessment of indirectly measured $^1O_2$ production rates against $H_2TMPyP$ were described and the relative singlet oxygen production yields were: free cationic bisporphyrins > $H_2TMPyP$. The results showed the cationic bisporphyrins with ${\beta}$-substitution and non ${\beta}$-substitution could be developed as potential photodynamic agents.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.931-935
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• 2013

Lipid events in liposome-mediated transfection (lipofection) are largely unknown. Here we studied whether phospholipase D (PLD), an important enzyme responsible for phospholipid breakdown, was affected during lipofection of HepG2 cells with a luciferase plasmid. Synthetic cholesterol (Chol) derivatives, including $3{\beta}$[L-ornithinamide-carbamoyl]Chol, [polyamidoamine-carbamoyl]Chol and $3{\beta}$[N-(N',N'-dimethylaminoethane)-carbamoyl]Chol, and a cationic lipid, N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride were mixed with a helper lipid dioleoylphosphatidylethanolamine to form respective cationic liposomes. All cationic liposomes were found to stimulate PLD. Although orders of magnitude effects of the cationic liposomes on PLD stimulation did not consistently match those on cytotoxicity and luciferase expression, a causal relationship between PLD activation and cytotoxic effect was remarkable. PLD stimulation by the cationic liposomes was likely due to their amphiphilic characters, leading to membrane perturbation, as supported by similar results obtained with other membrane-perturbing chemicals such as oleate, melittin, and digitonin. Our results suggest that lipofection induces cellular lipid changes such as a PLD-driven phospholipid turnover.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.1 s.109
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• pp.1-9
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• 2005

Many factors which affect the adsorption of cationic polymers on fibers and fines have been investigated by many researchers that include contact time, pH, collision frequency, properties of cationic polymers and adsorbent, etc. But the effect of white water quality on the adsorption of cationic polymer have not been examined throughly. In this study, the adsorption of cationic PAM was analyzed as a function of white water quality. The adsorption of the cationic PAM was analyzed by two analysis methods, Kjeldahl nitrogen content measurement and electrokinetic measurements. When the distilled water was used, adsorbed amount of C-PAM and zeta-potential of fibers increased as a function of the addition of C-PAM. When closure level increased, nitrogen content of fibers increased indicating that the cationic PAM was adsorbed. Zeta-potential of fibers, however, showed no significant change with the increased addition of C-PAM. This showed that adsorption of C-PAM was not reflected by zeta-potential of fibers due to the deteriorated efficiency of C-PAM by the anionic contaminants in white water.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1433-1436
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• 1999

The 2-(2,4-dimethoxyphenyl)-4-MDO (2) underwent polymerization with ring opening as well as cyclization reaction in the presence of various cationic catalysts such as boron trifluoride, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid and trifluoroacetic acid. They afforded a mixture of the ring-opened poly(keto ether) and 3(2H)-dihydrofuranone derivative. Both the methylene group and oxygen atom of 1,3-dioxolane ring were participated in the reaction with cationic catalyst. The contents of the polymer and cyclization product were variable according to the acid strength of the cationic catalysts.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.277-282
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• 1998

Whereas cationic extracellular peroxidases (PODs) were observed in the suspension cultures of rose (Rosa sp. L. cv Pual's scarlet) grown under normal conditions, new anionic isozymes were induced within 24 hr by the treatment of low host-specific elicitor (10 mg glucan/L media) prepared from yeast cell wall. Prominent anionic (pI 6.1) and cationic POD (pI 8.4) were purified and characterized to understand the physiological role of the enzymes. Both enzymes were purified (ca.200 fold) by the ammonium sulfate precipitation, ion exchange chromate-graphy and gel filtration chromatography. The Km values of the purified anionic POD for ferulic acid and $\textrm{H}_2\textrm{O}_2$ were 4.64 mM and 0.72 mM, whereas those of the cationic POD were 1.38 mM and 0.48 mM, respetively. The activity of the anionic POD as NADH oxidase was twice higher than that of cationic POD. The NADH oxidation in the anionic POD fraction was inhibited by 60% on the addition of 0.1 mM coniferyl alcohol, while that in the cationic fraction was inhibited by 15%.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.85-90
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• 2006

Increasing the filler content of sheet improves the optical properties and printability of paper and provides an opportunity for saving production cost through fiber replacement with relatively low-priced filler. But increasing the filler content tends to decrease the strength of paper and filler retention. It also tends to deteriorate drainage on the paper machine. To overcome these problems, preflocculation technology of fillers may be employed. Many research efforts have been made on the properties of preflocculated filler, namely prefloc, whose size and size distribution were influenced by polymer type and shear level. But there is much to be investigated about the effect of the prefloc characteristics on the physical properties of paper. To evaluate the effect cationic polymers on the size and size distribution of preflocculated GCC and their shear stability, cationic PAM and cationic starch were used. The influence of the preflocculation on filler retention and its surface distribution, and the changes of physical and optical properties of handsheets affected by the characteristics of preflocs were examined. Filler distribution on sheet surface was also analyzed by EPMA. Results showed that cationic PAM formed large preflocs at low dosage. Cationic starch was required to add 15 times as much as cationic PAM to obtain the preflocs with similar size. But preflocs formed with cationic starch was superior in shear stability to those formed with cationic PAM. Filler preflocculation technology could provide an opportunity of increasing filler content significantly without loss in tensile strength. And increased filler contents could compensate brightness loss which often accompanies filler preflocculation. When excessively large preflocs were used, however, brightness loss rather than the improvement in tensile strength was predominant. Therefore it is of great importance to produce preflocs with proper size and shear stability for maximizing the improvement of physical properties of papers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.2
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• pp.8-17
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• 2012

Three kinds of cationic acrylamide copolymer with different branch degree were prepared controlling the dosage of N, N'-methylenebisacrylamide. The physical characteristics of the branch-degree-modified copolymers were analyzed by intrinsic viscosity and charge density. The branch degree measurements were investigated by applying the colloidal titration phenomena using a spectrophotometer and comparison with the cationic regain measurement method. The results showed that the absorbance behaviors of spectrophotometer were distinctively different with the branch degree of copolymers. Also, the branch degree determinations and molecular structure estimations of the copolymers were numerically measured by applying the titration phenomena using a spectrophotometer. Finally, three kinds of branch-degree-modified copolymers were applied to flocculation test using arbocel micro pulp for the determination of flocculation behavior by different morphology of cationic acrylamide copolymers.

• Textile Coloration and Finishing
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• v.15 no.5
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• pp.294-300
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• 2003

The anionic agent containing dichloro-s-triazinyl reactive group was synthesized and applied to the cotton fabrics to introduce covalent bonds. This attempt was expected to improve the affinities of cationic compounds, such as cationic dyes, chitosan, quaternary ammonium antimicrobial agents and metal ions, by the electrostatic attractive force. As expected, the anionic agent was reacted with cotton fabrics at room temperature. In order to examine the adsorptivity of the cationic compounds on to the anionized cotton fabrics, firstly a cationic dye(C. I. Basic Violet 7) was applied. The color strength of the dyeing of anioized cotton fabric was highly increased comparing to that of untreated fabric.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.625-631
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• 2015

In this study, low cost bio-flocculants, chitosan, cationic starch and Mg-sericite, were used as a flocculant to harvest freshwater microalgae, Chlorella vulgaris. Chitosan, cationic starch and Mg-sericite separated successfully >98% of C. vulgaris at following optimal parameters: 90 mg/L chitosan at pH 6-7, 70 mg/L cationic starch at pH 9-10 and 50 mg/L Mg-sericite at pH 4-5. A relatively high correlation coefficient (R²) of 0.9993 for chitosan, 0.9971 for catonic starch and 0.9924 for Mg-sericite was obtained. The investigated flocculants amount increased linearly with increasing the microalgae amount. The biopolymer, Mg-sericite, was more effective than that of other investigated flocculants. These results indicated that a bio-flocculants, chitosan, cationic starch and Mg-sericite, could prove to be an effective flocculant for economical production of microalgae biomass. In addition, Mg-sericite was more effective comparing to the other investigated flocculants.