• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.83-92
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• 2020

This study investigated the optimal conditions of enzymatic reaction for production of isomaltooligosaccharides (IMO) using rice flour. To manufacture IMO, commercial enzymes (Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L and Transglucosidase L) were used. The sugar composition and amount of IMO were examined by HPLC with charged aerosol detector (HPLC-CAD) in each manufacturing process. Liquefaction reaction was performed according to different Termamyl 2X concentrations (0.025%, 0.05%, 0.075%, 0.1%) and reaction times (1 h, 2 h). As a result, the reducing sugar content was the highest at 138.26 g/L when 0.075% Termamyl 2X was added for 2 hours. In order to optimize simultaneous saccharification and transglucosylation, experiments on enzyme selection, enzyme concentration and enzyme reaction time were conducted. Reaction with 0.0015% Maltogenase L, 0.05-0.1% Promozyme D2 and 0.1% Tansglucosidase L was effective in decreasing glucose content and increasing content of IMO with a high degree of polymerization. A change in sugar content was observed every 6 hours to determine the optimal reaction time, and the highest IMO was produced after 36 hours of reaction (75.36 g/L). The IMO prepared under optimal conditions showed isomaltose, 35.11 g/L; panose, 11.97 g/L; isomaltotriose, 19.95 g/L; isomaltotetraose, 7.46 g/L; isomaltopentaose, 1.05 g/L at 18 brix and the ratio of IMO in the total sugar was 56.37%.

• Polymer(Korea)
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• v.35 no.2
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• pp.166-170
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• 2011

This study reported the synthesis of perfluoropolyether intermediate (TP-$COOCF_3$) having a $CF_3$ functional group via electrophilic fluorine substituting direct fluorination from PFPE intermediate (TP-$COOCH_3$) having a $CH_3$ functional group, which was synthesized by the ring opening polymerization and methyl esterification of HFPO. The effects of reaction conditions such as the amount of solvent, fluorine partial pressure, reaction time, were investigated. The results showed that the yield of fluorination reaction became the highest when the reaction was carried out in a mild condition for a long reaction time, which also minimized side reactions. The sample was characterized by FTIR and NMR, which confirmed the synthesis of the final product, TP-$COOCF_3$, via direct fluorination converting $CH_3$ of TP-$COOCH_3$ to $CF_3$ of TP-$COOCF_3$ with 95.4% yield.

• Polymer(Korea)
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• v.32 no.1
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• pp.70-76
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• 2008

The PES-g-BTCA membrane was synthesized by UV irradiation method and then used to be modified into the PES anion exchange membrane by the amination reaction. Their chemical structures and adsorption properties were investigated. The degree of grafting and amination were increased with increasing the reaction time and had the maximum values of 138% and 1.20 mmol/g at 80 min, respectively. The initial thermal degradation temperature of PES membrane was $400^{\circ}C$. Which was reduced as the surface modification reaction had proceeded. The values of contact angle for PES membrane were decreased from 68.1 to $40.2^{\circ}$ with increasing the extent of amination, the water up-take and ion exchange capacity were also increased with increasing UV irradiation time until 80 min. The average pore size and BET surface area were decreased in order of PES, PES-g-BTCA, and aminated PES ion exchange membrane. Their average pore sizes were 624.8, 359.7, and 138.5 ${\AA}$, and their surface areas were 10.1,9.7 and 1.7 $m^2/g$, respectively.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.346-351
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• 2017

This study was planned considering the chain length, hydrophilicity, and hydrophobicity of the additives to be used in the polymerization, while various ophthalmic lenses that use various additives with similar water contents were manufactured before their optical and physical properties were compared and analyzed. With regard to the additives required for manufacturing high-, medium-, and low-water content lens groups, HEA (hydroxyethyl acrylate), PVP (polyvinylpyrrolidone), and NMV(N-methyl-N-vinylacetamide) were used as additives for preparing the high-water content lens group, HEMA(2-hydroxyethyl methacrylate), HPMA(hydroxypropyl methacrylate) and BD(1,4-butanediol) were used for the medium-water content lens group. For the low-water content lens group, BMA(buthyl methacrylate), BDDA(1,4-butanediol diacrylate), and Bis-GMA(bisphenol A glycerolate diacrylate) were used, respectively. The average water content of HEA was 40.14%; that of PVP, 39.63%; and that of NMV, 40.52%. The mean of water content was 35.92% for HEMA, 35.74% for BD, and 34.62% for HPMA. For the low-water content lens group, the mean of water content was 26.69% for BMA, 27.76% for BDDA, and 26.14% for Bis-GMA. With regard to the results of the water content measurement using a moisture analyzer, the average water content of the high-water content lens group was 41.34% for HEA, 42.62% for PVP, and 42.73% for NMV. Finally, for the low-water content lens group, the average water content was 28.62% for BMA, 28.82% for BDDA, and 28.32% for Bis-GMA. The measurements of the water contents of the lenses using the two methods showed that the water content and refractive index of the lenses were similar in all the lens groups. The measurements of the contact angles, however, showed a different wettability value for each lens with a similar water content. Also, the change tendency of the lens curvature according to the change of time showed that the change amount became larger and the recovery time became longer from the lens samples with a lower water content to those with a higher water content. Based on these results that will be helpful for the study of ophthalmic lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.45-50
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• 2008

Purpose: A soft contact lens was manufactured by adding naringin known as natural anti-bacterial material to resin solution. With solution eluted from manufactured contact lens, we examined its optical properties, physical and chemical states of naringin in the polymer, and elution properties. Methods: The soft contact lens with naringin was synthesized by bulk polymerization method. IR spectrum and HPLC were used to define the bonding type of naringin itself in the soft contact lens contained naringin, elution process of naringin to the saline solution, and the amount of naringin solution eluted from the lens with elapsed time. Results: Naringin was continuously eluted with constant concentration from the soft contact lens for about a month and the structure ofnaringin which is eluted was as same as before it was added to resin solution. Any change in optical properties such as transmittance couldn't be found. Bonding state and the structure of naringin in contact lens were explained with IR spectrum and HPLC results. Conclusions: In the contact lens with naringin, naringin remained in the contact lens bonding with weak hydrogen bonding and/or van der Waals force between naringin and polymer. Naringin was continuously eluted from the contact lens contained naringin during about 1 month. Even after 1 month, it showed that the concentration of the naringin eluted was approximately 10 ppm in a day. From the results, adding naringin to the soft contact lens resin is very effective method for manufacturing the soft contact lens which has anti-bacterial function for a period of time.

• Membrane Journal
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• v.29 no.1
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• pp.44-50
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• 2019

In this paper, we developed mixed matrix membranes (MMMs) consisting of SBS-g-POEM block-graft copolymer, ionic liquid (EMIMTFSI) and ZIF-8 nanoparticles to separate a $CO_2/N_2$ gas pair. The SBS-g-POEM is a rubbery block-graft copolymer synthesized through low-cost free-radical polymerization. The EMIMTFSI was dissolved into the SBS-g-POEM matrix and solution synthesized ZIF-8 nanoparticles were also dispersed into the copolymer matrix. The physico-chemical properties of manufactured membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), which showed that the components were compatible with each other. The gas separation performance was confirmed by time-lag measurements showing $CO_2$ permeability of 537.0 barrer and $CO_2/N_2$ selectivity of 15.2. The result represents the EMIMTFSI and ZIF-8 nanoparticles improves the gas permeability more than two-times, without significantly sacrificing the $CO_2/N_2$ selectivity.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.623-631
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• 2007

Effect of Soft-start curing on the contraction stress of composite resin restoration polymerized with LED and plasma curing unit The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin (Filtek $Z-250^{TM}$, 3M ESPE, USA) was cured using the one-step continuous curing method with three difference light sources ; conventional halogen light ($XL3000^{TM}$, 3M ESPE, USA) cure for 40 seconds at $400 mw/cm^2$, LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure for 20 seconds at $800\;mW/cm^2$ a and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure for 12 seconds at $1300 mW/cm^2$. For the soft-start curing method ; LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure exponential increase with 5 seconds followed by 17 seconds at $800\;mW/cm^2$ and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure 2 seconds light exposure at $650\;mW/cm^2$ followed by 11 seconds at $1300\;mW/cm^2$. The strain guage method was used for determination of polymerization contraction. Measurements were recorded at each 2 second for the total of 800 seconds including the periods of light application. Obtained data were analyzed statically using Repeated measures ANOVA, One way ANOVA, and Tukey test. The results of present study can be summarized as follows: 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05). 2. Contraction stress was not revealed significant difference between Halogen curing light groups and LED and Plasma Light curing with soft-start group (P>0.05). 3. LED and Plasma Light curing with soft-start showed lower contraction stress than the one-step continuous light curing (P<0.05).

• Journal of dental hygiene science
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• v.12 no.4
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• pp.342-347
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• 2012

This study is a temporary crowns and the period you want to avoid the exposure of the coffee girl polymerization types is difficult given the temporary tolerance by producing resin. 1. Change of brightness ($L^*$) edge in time increases, distilled water, Americano, Cafelatte, Vanillalatte was reduced to a significant level of brightness (p<.001). The most significant decrease in brightness of the Americano, which tend to grow out of a Cafelatte, Vanillalatte, which was followed by distilled water. 2. Change of redness ($a^*$) edge in time tend to increase saturation increases, the redness value of Americano, Cafelatte, redness value was a statistically significant difference in distilled water and Vanillalatte (p<.05) was not significant. 3. Change of yellowness ($b^*$) edge in time tend to increase saturation increases, the yellowness value of Cafelatte, Vanillalatte, Americano, except for distilled water at the saturation of yellowness value were no statistically significant (p<.05). 4. Change of color difference (${\Delta}E^*$) in order of (Americano>Cafelatte>Vanillalatte) as time of immersion increases change of color difference appear and no statistically significant (p<.05). Americano, the edge, since there can be more than chrominance is 3.3 uses station than a Vanillalatte, Cafelatte and discoloration when edge in 28, since even in the one to two difficult to distinguish with the naked eye as a discoloration. It was no difference statistically in color difference (${\Delta}E^*$) value in distilled water (p>.05).

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.54-61
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• 2008

Purpose : This study was designed to clarify the mechanism of proteinuria in nephrotic syndrome patients by using puromycin aminonucleoside (PAN) nephrosis model. Methods : Following administration of various concentrations of PAN and antioxidants we observed the changes of podocyte cytoskeletons in cultured rat glomerular epithelial cells (GEpC) by method of scanning electron microscope, reactive oxyten species (ROS) analysis, permeability assay, confocal microscope, and Western blot assay. Results : PAN not only induced the ultrastructural changes of GEpC, such as shortening and fusion of microvilli, but also separated the intercellular gaps and linear ZO-1. PAN induced oxidative stresses in time and dose dependent manners and increases of intercellular permeability in anti-oxidants inhibitable manners. High concentration of PAN induced not only actin polymerization and disorganization, but also the conglomerulation and internal dislocation of ${\alpha}-actinin$ protein. The intensities of fluorescences of ZO-1 protein were diminished and internalized by PAN in a dose-dependent manner, which were inhibited by anti anti-oxidants. Conclusion : PAN induced the changes of podocytes cytoskeleton and junctional barriers by way of increasing ROS in GEpC that resulted in increasing their permeability in a antioxidatn-inhibitable manner. Glomerular hyperpermeability induced by PAN mediateing through oxidative stresses is thought to take part in the mechanism of proteinuria in nephrotic syndrome.

• Korean Journal of Food Science and Technology
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• v.12 no.1
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• pp.45-52
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• 1980

The nylon (poly 6, 10) microcapsules containing ${\beta}-galactosidase$ were obtained by the interfacial polymerization of 1, 6-diaminohexane and sebacoyl chloride with ${\beta}-galactosidase$ from Escherichia coli. They were generally spherical and had a mean diameter of $80{\mu}$ with 45 % of the activity recovery. In particular, there was no transport hamper of lactose through the membrane of microcapsules. The characteristics of the microencapsulated enzyme were similar to those of soluble enzyme optimal pHs, $7.0{\sim}7.2$ for the soluble and $7.3{\sim}7.5$ for the microencapsulated ; optimal temperatures, $50^{\circ}C$ for both ; apparent $K_m,\;3.33{\times}10^{-4}(on ONPG),$ $2.86{\times}10^{-3}$ M(on lactose) for the soluble and $5.28{\times}10^{-4}$ (on ONPG), $4.25{\times}10^{-3}$ M (on lactose) for the microencapsulated ; activation energies, 8.94 for the soluble and 9.78 Kcal/mole for the microencapsulated enzyme. Using this microencapsulated ${\beta}-galactosidase$, hydrolyses of lactose and milk lactose were carried out and 80 % of 5 % lactose solution and 70 % of lactose in skim milk were hydrolyzed in 40 hr at $27^{\circ}C$. The reusability and operational stability showed that the remaining activity was 50 % of the original activity after 5 runs and 120 hr of total operating time at $27^{\circ}C$.