• Korean Journal of Human Ecology
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• v.1 no.1
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• pp.103-112
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• 1998

Cotton fabric was treated with chitosan by pad-dry(-cure) method to impart antimicrobial properties. Four chitosans of different degree of deacetylation (DAC: 65~95%) with similar molecular weight(MW: ca. 50, 000) and one chitosan oligomer(MW 1, 800, DAC 86%) were used. In order to improve the durability to laundering of antimicrobial activity for the fabrics treated with chitosan oligomer, crosslinker or binder was included in the finishing formulation. Antimicrobial activity against Staphylococcus aureus and Proteus vulgaris was evaluated by the Shake Flask Method. The treated fabrics were laundered up to 20 times according to AATCC Test Method 60-1986 or JIS 0217-104 and antimicrobial activity of the laundered fabrics was evaluated. The antimicrobial activity was increased with the increase of concentration and degree of deacetylation of chitosan. And the cured fabrics showed better durability to laundering than the not-cured fabrics according to AATCC Test Method 60-1986. Crosslinker and binder decreased antimicrobial according of the fabrics treated with chitosan oligomer and were not effective to improve the durability to laundering according to JIS 0217-104. (Korean J Human Ecology 1(1) : 103~112, 1998)

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.66-70
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• 2006

Magnetite nanoparticles, which have been extensively used in many fields, were encapsulated with a natural polymer, chitosan, to improve their biocompatibility. We have synthesized magnetite $(Fe_3C_4)$ nanoparticles using chemical coprecipitation technique with sodium oleate as surfactant. Nanoparticle size can be varied from 1.2 to 7.4nm by controlling the sodium oleate concentration. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetic colloid suspensions containing particles with sodium oleate and chitosan have been prepared. High magnetic property chitosan-microsphere particles were prepared from oleate-coated magnetite suspension using spray method. The surftce, and tile morphology of the magnetic chitosan microsphere particles were characterized using optical microscope and scanning electron microscope. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the chitosan microspheres including magnetite nanoparticles. The SQUID measurements revealed superparamagnetism of nanoparticles.

• Polymer(Korea)
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• v.28 no.4
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• pp.291-297
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• 2004

Water-soluble chitosan micro spheres were prepared by emulsification of chitosan solution in mineral oil followed by cross linking reaction with different amount of the cross linking agent (glutraraldehyde), different chitosan concentration. Then, the physicochemical properties such as morphological change by degradation, drug loading efficiency, and drug release profiles were investigated with the drug loaded water-soluble chitosan microspheres. Norfloxacin loaded water-soluble chitosan micro spheres showed excellent drug entrapping capacities without burst release caused by surface bound drug. The absence of the surface bound drug also confirmed by X-ray diffraction study. Degradation and drug release studies showed that the amount of the crosslinking agent played a crucial role for drug loading, release and degradation. The water-soluble chitosan micro spheres showed more sustained drug release profiles with slower degradation and larger particle size by increasing crosslinking agent.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.855-861
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• 1998

Composite films based on ${\kappa}-carrageenan$ and chitosan were prepared, and tensile strength (TS), elongation (E), and water vapor permeability (WVP) of the films were measured. The molecular weight of ${\kappa}-carrageenan$ and chitosan was measured by a light-scattering instrument and was $5.1{\times}10^5,{\;}and{\;}1.71{\times}10^5$, respectively. TS of ${\kappa}-carrageenan$ and chitosan free film was 30.2 MPa and 21.0 MPa, respectively. TS of composite film was not related to the amount of the ascorbic acid. E of composite film was lower than those of the free films of ${\kappa}-carrageenan$ and chitosan. WVP of composite film was lower than that of chitosan film and was similar to WVP of ${\kappa}-carrageenan$ film.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.167-174
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• 2006

This study was initiated to investigate the effect of chitosan on creeping bentgrass growth. Chitosan was applied several times in dilution of 300, 500 and 800 times at ten-day intervals after transplanting. Such growth characteristics as leaf length, root length, numbers of leaves, fresh weight and dry weight and chlorophyll content were observed. Treatment of 500 times diluted chitosan resulted in the longest root length, being 31.5cm while the control the shortest root of 25.1cm. Leaf numbers were 27.9 and 45.5, respectively for the control and the 300 times treatment. The highest chlorophyll content was associated with treatment of 300 times diluted chitosan and the lowest one with the control, resulting in 11.9 and $18.4mg/100cm^2$, respectively. We found that leaf number, chlorophyll content, fresh and dry weight were higher in the treatment of 500 times than the other treatments.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.198-208
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• 2021

The aim of this study was to evaluate the antibacterial effect on Enterococcus Faecalis and physical properties of chitosan added calcium hydroxide canal filling material. Low, medium, high molecular weights of chitosan powder were mixed with calcium hydroxide canal filling material. Also, for each molecular weight group, 1.0, 2.0, 5.0 wt% of chitosan powder were added. An overnight culture of E. faecalis was adjusted to 1 × 10⁶ CFU/ml. For test of antibacterial effect, three different molecular weights of 2.0 wt% chitosan and three different concentrations of high molecular weight chitosan were mixed with calcium hydroxide canal filling material. The absorbance of plates was analyzed using spectrophotometer at 570 nm with a reference wavelength of 600 nm. Physical properties such as flow, film thickness and radiopacity were examined according to ISO 6876 : 2012. All molecular weight type of chitosan containing material showed inhibitory effect against E. faecalis growth compared to non-chitosan added calcium hydroxide canal filling material group (p < 0.05). High molecular weight chitosan containing material showed the most antibacterial effect. Also, the antibacterial effect decreased as the incorporated amount of chitosan decreased (p < 0.05). Every molecular weight group of material containing chitosan had a tendency for reduced flow and radiopacity, increased film thickness according to amount of chitosan. Low molecular weight of 1.0 wt% chitosan addition did not show any significant difference of physical properties compared to conventional calcium hydroxide canal filling material. In conclusion, for reinforcement of antibacterial effect against E. faecalis and for favorable physical properties, 2.0 wt% of chitosan adding is recommended. Considering its antibacterial effect of chitosan, further studies are required for clinical application of chitosan in endodontics and pediatric dentistry.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.10a
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• pp.36-37
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• 1995

투과증발법은 기존의 증류법에 의해 분리되기 어려운 혼합물(공비혼합물이나 끓는점이 비슷한 혼합물)이외에 열에 민감한 생성물의 분리, 과익쥬스의 농축, 불순물 찌꺼기의 제거, 정량 검출을 위한 유기 오염물질의 농축 등에 이용되었으며 특히 물과 에탄올의 공비혼합물의 분리와 물로부터 희박 유기물질을 회수하는데 행해져 왔다. 본 연구에서 사용된 키토산은 친수성기들을 가지고 있기 때문에 물과 알코올의 분리에서 물을 선택적으로 투과시켜 효과적인 투과증발막으로 사용될 수 있으며 투과속도를 높이기 위해서 활성층이 매우 얇은 복합막을 제조하였다. 또한 키토산 복합막을 다양한 가교제 (glutaraldehyde, glyoxal, terephthalaldehyde, 황산등)로 가교한 막들을 열처리를 하거나 키토산과 PVA를 블렌드하여 제조한 키토산/PVA 블렌드 복합막을 이용하여 에탄올/물, IPA/물 혼합용액에서의 탈수 실험을 실시하여 이에 따른 투과성능의 영향을 살펴보았다.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.399-403
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• 1998

The gelation characteristics of chitosan of different molecular weight were investigated in terms of concentration and temperature of alkari aqueous solution. The average molecular weights and the degrees of deacetylation of the chitosan used were $2.0{\times}10^5$, $5.2{\times}10^5$, $8.2{\times}10^5$ and 85%, respectively. Sodium hydroxide solution was used as a gelation agent. A simple diffusion model was applied to study the gelation rate. The diffusion coefficients of the gelation agent in the chitosan gel increased with increasing its concentration, temperature of the casting solution, and molecular weight of the chitosan.

• Polymer(Korea)
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• v.34 no.6
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• pp.501-506
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• 2010

Natural chitosan has high molecular weight and the poor solubility in water. Water-soluble chitosan with low molecular weight was prepared by the hydrolysis method. In order to develop an efficient gene delivery carrier, chitosan was conjugated with lipoic acid to form the comb-type copolymer. The copolymer with the amphiphilic property formed the self-assembled nanoparticles in the aqueous solution. The average size of nanoparticles was 217.6 nm and the average size of nanoparticles/DNA complex was 170 nm. New chitosan-lipoic acid copolymer showed the low cytotoxicity and 10 times higher transfection efficiency than that of the pure chitosan.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.193-198
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• 1999

The optimal culture condition of Bacillus sp. P16 was investigated for production of an extracellular endo-splitting chitosanase. The best carbon and nitrogen sources for the chitosanase production were chitosan and tryptone, respectively. The best condition for the maximum activity was at $37^{\circ}C$ in a medium containing 0.5% powdered chitosan, 1% tryptone, and 1% NaCl(at initial pH 7.0) in a rotary shaker(200 rpm). In a jar fermenter, the culture duration shortened to $6{\sim}12$ hr for maximum activity and the enzyme activity increased about 100% compared with that of flask culture.