• Korean Journal of Dental Materials
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• v.44 no.1
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• pp.69-77
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• 2017

The aim of this study was to investigate the effects of chitosan powder addition on the strengthening of conventional glass ionomer cement. Two types of chitosan powders with different molecular weight were mixed with conventional glass ionomer cement (GIC): low-molecular weight chitosan (CL; 50~190 kDa), high-molecular weight chitosan (CH; 310~375 kDa). The chitosan powders (CL and CH) were separately added into the GIC liquid (0.25-0.5 wt%) under magnetic stirring, or mixed with the GIC powder by ball-milling for 24 h using zirconia balls. The mixing ratio of prepared cement was 2:1 for powder to liquid. Net setting time of cements was measured by ISO 9917-1. The specimens for the compressive strength (CS; $4{\times}6mm$), diametral tensile strength (DTS; $6{\times}4mm$), three-point flexure (FS; $2{\times}2{\times}25mm$) with flexure modulus (FM) were obtained from cements at 1, 7, and 14 days after storing in distilled water at $(37{\pm}1)^{\circ}C$. All mechanical strength tests were conducted with a cross-head speed of 1 mm/min. Data were statistically analyzed by one-way ANOVA and Tukey HSD post-hoc test. The mechanical properties of conventional glass ionomer cement was significantly enhanced by addition of 0.5 wt% CL to cement liquid (CS, DTS), or by addition of 10 wt% CH (FS) to cement powder. The CL particles incorporated into the set cement were firmly bonded to the GIC matrix (SEM). Within the limitation of this study, the results indicated that chitosan powders can be successfully added to enhance the mechanical properties of conventional GIC.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.188-197
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• 2021

In this study, the optimal conditions for hair dyeing using sappan wood (Caesalpinia sappan L.) powder were determined, and then the effect of chitosan treatment on the hair dyeing properties of sappan wood powder was investigated. Treatment of sappan wood powder and water with the ratio of 1:3 (w/w) at 40℃ for 60 minutes was found to be the most effective to hair dyeing. In addition, the pretreatment of low molecular weight (~30 kDa) chitosan at a concentration of 1% (w/w) prior to treatment with sappan wood powder effectively improved and maintained the hair dyeing properties of sappan wood. In conclusion, the low molecular weight chitosan is considered to be of great help as a mordant in improving the dyeing efficiency and retention of sappan wood powder in hair dyeing.

• Culinary science and hospitality research
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• v.10 no.4
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• pp.190-200
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• 2004

This study was carried out to investigate the effects of intake of whangseoke-jeot with chitosan on the hematological changes. Twelve male students were divided into two groups and have been dieted for 3 days with whangseoke-jeot supplemented with/without 10% of chitosan(50,000 dalton) into seasoning. In order to decrease fishy smell and increase palatable taste effectively, minced ginger, garlic and onion as well as oil and roasted powder of perilla were included into the seasonings. Blood pressure was monitored everyday and serum was prepared following blood collection before and after 3 day diet. Chitosan was shown to decrease systolic pressure and total serum protein. On the other hand, albumin was decreased in the control group. It is noteworthy that seasoned whangseoke-jeot including perilla oil and powder seemed to decrease creatinine and total cholesterol and increase HDL. In conclusion, chitosan and perilla oil and powder might be proposed as good additives into whangseoke-jeot to relieve its highly salty effects on diet.

• Textile Coloration and Finishing
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• v.23 no.1
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• pp.21-27
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• 2011

The natural dyeing of cotton fabric with gardenia blue powder was studied. Cotton fabrics were treated with chitosan in order to increase K/S values and colorfastness. K/S values were increased with increasing the concentration of gardenia blue powder, dyeing time and temperature, and the lower pH of dye bath. In case of chitosan finishing, K/S values were increased, and ${\lambda}_{max}$ shifted to 600nm at 400nm. The wash fastness was improved, but the abrasion fastness was lowered in the case of wet rubbing.

• Animal cells and systems
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• v.1 no.2
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• pp.337-340
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• 1997

The purpose of this study is to evaluate whether water soluble chitosan, a natural nontoxic chelator, can reduce fetal contamination of radiostrontium in pregnant mice. Various forms of water soluble chitosans (10% or 1% powder, or 1% solution) were given to pregnant mice before or after contamination of 0.005 uCi/B.W(g) Sr-85. Transplacental transfer of Sr-85 to fetus was $6.8{\pm}2.7%$ of injected dose, when Sr-85 was administered at the 20th day of pregnancy. Fetal radioactivity was significantly reduced when mother mice were treated with water soluble chitosan before contamination of Sr-85. Water soluble chitosans of 10% or 1% powder, or 1% solution significantly reduced fetal retention of Sr-85 to $2.3{\pm}0.7%$, $2.7{\pm}0.8%$, and $2.0{\pm}0.9%$, respectively. However, fetal contamination was not reduced, when water soluble chitosans of 10% or 1% powder, or 1% solution were administered after maternal contamination of Sr-85. From these data we can conclude that water soluble chitosan could reduce fetal contamination of radiostrontium in pregnant mice, when given before the pregnant mice were exposed to radiostrontium.

• Horticultural Science & Technology
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• v.30 no.3
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• pp.261-269
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• 2012

Soil microbial community and soil physiological parameters were investigated by analyzing phospholipid fatty acids extracted from the soils amended with chitosan powder and solution in a cucumber greenhouse. The soils were sampled at 90, 160, 200 days after treatment. Identified fatty acids were analyzed with principal component (PC) analysis. Chitosan powder soils and chitosan solution soils were separated from non-treated control soils by PC1 and PC2 90 days after treatment, respectively. And chitosan powder soils were separated from non-treated control soils by PC2 160 days after treatment. The ratio of fungi to bacteria increased significantly in chitosan solution-amended soils compared with the control soils 90 days after treatment. Microbial groups and physiological parameters were investigated 160 days after treatment: vesicular-arbuscular mycorrhizal fungi (VAM) significantly increased in soils amended with chitosan powder compared with other soils, the ratio of gram negative bacteria to gram positive bacteria and cyclo-fatty acids to precursors were significantly higher and lower in soils amended with chitosan solution and chitosan powder compared with control soils, respectively, and the ratio of fungi to bacteria were significantly lower in control soils compared with chitosan-treated soils. The chitosan powder increased the ratio of aerobic to anaerobic bacteria and lowered the ratio of saturated to unsaturated fatty acids compared with chitosan solution 200 days after soil application. In conclusion, chitosan powder changed the soil microbial community and the effects maintained up to 160 days after soil application. The effect of physiological parameters on the soil microbial community started to appear 160 days after and continued up to 200 days after soil application of chitosan.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.375-381
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• 2021

Chitosan powder is synthesized by a deasetylation process of chitin, obtained from processing of dried shrimp shell powder. Subsequently, chitosan (CS) membranes filled by montmorillonite (MMT) particles and phosphotungstic acid are prepared, and characterized by FT-IR and SEM. The morphology, obtained by SEM for the composite membrane, showed that MMT filler is successfully incorporated and relatively well dispersed in the chitosan polymer matrix. Water and methanol uptake for the CS/MMT composite membranes decrease with increasing MMT loadings, but IEC value increases. In all prepared CS/MMT composite membranes, the CS membrane filled by 5 wt% MMT particles exhibits the best proton conductivity, while that with 10 wt% MMT loading exhibits the lowest methanol permeability; these values are 2.67 mS·cm^-1 and 3.40 × 10^-7 cm²·s^-1, respectively. The best membrane selectivity is shown in the CS/MMT10 composite membrane; this shows that 10 wt% filled MMT is the optimum loading to improve the performance of the chitosan composite membrane. These characteristics make the developed chitosan composite membranes a promising electrolyte for direct methanol fuel cell (DMFC) application.

• Environmental Engineering Research
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• v.17 no.3
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• pp.151-156
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• 2012

This research described the magnetic method for the rapid removal of green algae in water. We modified the pH, cation concentration, and magnetic powder concentration to discover the best removal performance. In order to rapidly remove green algae from water, we added magnetic powder and chitosan into algae water to make a magnetic substance and this was extracted by a strong neodymium magnet. The optimized conditions were pH of 6.5-7.5, chitosan concentration of 10 mg/L, and magnetite powder concentration of less than 0.05%. A higher removing rate was observed when a higher amount of magnetite or chitosan was used, but the total amounts of phosphorus or nitrogen were not decreased.

• Restorative Dentistry and Endodontics
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• v.38 no.1
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• pp.36-42
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• 2013

Objectives: This study evaluated the antibacterial effect and mechanical properties of composite resins ($L_{CR}$, $M_{CR}$, $H_{CR}$) incorporating chitosan with three different molecular weights (L, Low; M, Medium; H, High). Materials and Methods: Streptococcus (S). mutans 100 mL and each chitosan powder were inoculated in sterilized 10 mL Brain-Heart Infusion (BHI) solution, and was centrifuged for 12 hr. Absorbance of the supernatent was measured at $OD_{660}$ to estimate the antibacterial activities of chitosan. After S. mutans was inoculated in the disc shaped chitosan-containing composite resins, the disc was cleansed with BHI and diluted with serial dilution method. S. mutans was spread on Mitis-salivarius bacitracin agar. After then, colony forming unit (CFU) was measured to verify the inhibitory effect on S. mutans biofilm. To ascertain the effect on the mechanical properties of composite resin, 3-point bending and Vickers hardness tests were done after 1 and 3 wk water storage, respectively. Using 2-way analysis of variance (ANOVA) and Scheffe test, statistical analysis was done with 95% significance level. Results: All chitosan powder showed inhibition effect against S. mutans. CFU number in chitosan-containing composite resins was smaller than that of control resin without chitosan. The chitosan containing composite resins did not show any significant difference in flexural strength and Vickers hardness in comparison with the control resin. However, the composite resin, $M_{CR}$ showed a slightly decreased flexural strength and the maximum load than those of control and the other composite resins $H_{CR}$ and $L_{CR}$. Conclusions: $L_{CR}$ and $H_{CR}$ would be recommended as a feasible antibacterial restorative due to its antibacterial nature and mechanical properties.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.3
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• pp.300-305
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• 2005

Along with development of modem medicine, the average life span has been increased but diseases of lifestyle such as cancer, obesity atheroscerosis, cardiac disorder become social issues. This study was designed to examine the availability of the functional food by adding chitosan-oligosaccharide to Korean traditional food, Soybean Dasik. For the study, 0, 30, 50 and $70\%$ of chitosan-oligosaccharide power that contains $23\%$ of chitosan-oligosaccharide were added to soybean Dasik in proportion to the total powder weight These were compared with the Soybean Dasik itself in relation to the physicochemical characteristics, sensory evaluation, and mechanical characteristics. The results of the research are as follows. Physicochemical characteristics showed that chitosan-oligosaccharide soybean Dasik had less ash, K, and Mn. As for the result of sensory evaluation, Dasik added $0\%$ chitosan-oligosaccharide was evaluated very good in its color. Sweetness and softness was good on $0\%\;30\%\;and\;50\%$ ones, while moistness and overall quality on $30\%\;and\;50\%$ ones. As the test results of mechanical characteristics, the chitosan-oligosaccharide soybean Dasik was good for hardness, cohesiveness, gumminess, and brittleness, especially on $0\%\;30\%\;and\;50\%$ ones. Springiness was good in all groups. In color, L value of chitosan-oligosaccharide soybean Dasik decreased but a and b values increased as the substitution percentage increased Therefore, the right amount of addition fit for the production properties was $30-50\%$ chitosan-oligosaccharide of total powder weight.