• Journal of fish pathology
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• v.27 no.2
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• pp.99-105
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• 2014

Biosensors consist of biochemical recognition agents like antibodies immobilized on the surfaces of transducers that change the recognition into a measurable electronic signal. Here we report a piezoelectric immunosensor made to detect Vibrio vulnificus. A 9MHz AT-cut piezoelectric wafer attached with two gold electrodes of 5mm diameter was used as the transducer of the QCM biosensor with a reproducibility of ${\pm}0.1Hz$ in frequency response. We have tried different approaches to immobilize antibody on the sensor chip. Concerning the orientation of antibody for the best antigen binding capacity, the antibody was immobilized by specific binding to protein G or by cross-linking through hydrazine. In addition, protein G was cross-linked on glutaraldehyde activated immine layer (PEI) or EDC/NHS activated sulfide monolayer (MPA). PEI was found to be more effective to immobilize protein G following glutaraldehyde activation than MPA. However, hydrazine chip showed a better capability to immobilize more IgG than protein G chip and a higher sensitivity. The sensor system was able to detect V. vulnificus in dose dependent manner and was able to detect bacterial cells within 5 minutes by monitoring frequency shifts in real time. The detection limit can be improved by preincubation to enrich the bacterial cell number.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4035-4040
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• 2012

Presented study describes the synthesis of photo cross-linkable and water soluble hydroxyethyl starch hydroxyethyl methacrylate (HESHEMA) samples with different degree of substitution (DS) by functionalization of hydroxyethyl starch (HES) with hydroxyethyl methacrylate (HEMA) or hydroxyethyl methacrylate carbonylimidazole (HEMACI) in DMSO using two different routes. It was revealed that the reaction time for HESHEMA synthesis can be reduced from 5 days to 24 h by conducting the reaction at $80^{\circ}C$ instead of at room temperature. Solubility of HESHEMA was found to be dependent on DS which in turn was dependent on ratio between HES and HEMA or HEMACI. HESHEMA samples with DS > 0.24 depicted insoluble in water, whereas the samples with DS < 0.05 did not form appreciable gel. HESHEMA samples with appropriate DS were converted into hydrogels by cross-linking polymer chains under UV radiations and resulting HESHEMA hydrogels showed swelling up to 1200%. Application of HESHEMA in controlled drug delivery was investigated by diffusion based encapsulation of Ondansetron, a serotonin 5-$HT_3$ receptor antagonist drug, mainly used for nausea and vomiting treatment.

• Membrane Journal
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• v.25 no.5
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• pp.391-397
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• 2015

The porous support polyvinylidene fluoride (PVDF) with a salting out based on the hollow fiber membrane polyethyleneimine (PEI) and polyvinylsulfonic acid (PVSA) by coating with by phase separated and pressurization (PSP) method to produce a multilayer membrane. The resulting membranes were characterized under the various conditions, such as the heat treatment temperature, coating concentration, feed concentration, cross-linking time and cross-link agent concentration in terms of flux and rejection rate for NaCl 100 ppm solution at 4 atm. The best results were PEI 20,000 ppm and PVSA 1,000 ppm, PEI 15% with a 2% malic acid aqueous solution coated by PSP method the hollow fiber membrane heat-treated for 1 minute showed flux 24.3 LMH, the rejection of 82.1%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.576-581
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• 2014

This study used the heat conductive silicone rubber sample of 0.95 mm thickness to research the properties of current by changing voltage. When the 1, 10, 30, 60, and 90 minute have passed, the running current has been measured through the applied voltage range of 200 V~800 V on setting temperature of $110^{\circ}C{\sim}170^{\circ}C$. As the temperature increased in applied voltage of 800 V, so did the current value according to time in proportion to the increasing temperature. In an analysis of FT-IR (fourier transform infrared) spectrum, the hydroxyl radicals group(O-H) was created by effects of the hydrogen that methyl group is eliminated by addition of the cross-linking agent peroxide.

• BMB Reports
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• v.32 no.5
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• pp.440-444
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• 1999

Membrane lipid peroxidation processes yield reactive aldehydes that may react with copper,zinc superoxide dismutase (Cu,Zn SOD), one of the key antioxidant enzymes against oxidative stress. We investigated this possibility and found that exposing Cu,Zn SOD to malondialdehyde (MDA) or 4-hydroxynonenal (HNE) caused the loss of dismutase activity, cross-linking of peptides, and an increase in protein oxidation, reflected by the increased level of carbonyl groups. When Cu,Zn SOD that had been exposed to MDA or HNE was subsequently analyzed by amino acid analysis, histidine content was found to be significantly lost. Both MDA-and HNE-treated Cu,Zn SOD were resistant to proteolysis, which may imply that damaged proteins exist in vivo for a longer period of time than the native enzyme. The lipid peroxidation-mediated damage to Cu,Zn SOD may result in the perturbation of cellular antioxidant defense mechanisms, and subsequently lead to a pro-oxidant condition.

• Macromolecular Research
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• v.13 no.2
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• pp.96-101
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• 2005

Thin-film humidity sensors were prepared using inorganic/organic hybrid polyelectrolytes, which were prepared from the sol-gel reaction of copolymers of [2-(methacryloyloxy)ethyl]dimethylpropylammonium bromide (MEPAB), n-butyl methacrylate (BMA), and 3-(trimethoxysilyl)propyl methacrylate (TSPM) with tetraethyl ortho-silicate (TEOS). The humidity-sensitive polyelectrolytes were composed of the copolymers having the following mole ratios of MEPAB, BMA, and TSPM: 60/30/10, 55/30/15, and 50/30/20. We found that the impedance varied with the content of MEPAB or TEOS; it ranged from $10^{7} to 10^{3}\Omega$ between 20 and $95\%$ relative humidity, which is the range required for a humidity sensor operating at ambient humidity. In addition we investigated a number of characteristics of these humidity sensors, such as their hysteresis, response time, temperature dependence, frequency dependence, water durability, and long-term stability.

• Fibers and Polymers
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• v.7 no.1
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• pp.36-41
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• 2006

PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.

• Elastomers and Composites
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• v.25 no.2
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• pp.112-116
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• 1990

In this study, as one way of developing the new cross-linking method that is curable in water, kinetic analysis of solution reaction between CR and silane coupling agents was attemped. First, CR was reacted with silane coupling agents in solution state. According to the time, reaction quantity was pursued by gas chromatography. Also, reaction rate coefficient and activation energy were calculated from the reaction quantity. Silane coupling agents which were used in this study were MPS, CPS and VES.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.223-226
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• 1995

Polymers have been developed and applied in many biomedical areas as well as engineering and industrial fields. The first essential to achieve successful development and applications is that properties of such polymer materials would be investigated. In many cases, such investigations are accomplished by observing polymeric behavior arising from the environmental changes such as pH, temperature, and ionic concentration. It has long been known that NMR is extremely sensitive to many biochemical and physical changes occurring in the polymer samples. In the present study we focus our study on NMR Microimaging, which is one of the important NMR applications, to characterize the swelling effect by observing the time dependent spatial variations of polymer specimens. For the samples three kinds of polyvinyl alcohol (PVA) specimens are prepared with different degrees of cross linking density. $^1H$ NMR microimages are acquired as a function of time to visualize the swelling behavior as well as volumetric changes occurring in the specimens. From the acquired time dependent images, the swelling process is exploited.

• Journal of Life Science
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• v.22 no.12
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• pp.1651-1657
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• 2012

Plectin and microtubule actin cross-linking factor 1 (MACF1) are architectural proteins that contribute to the function of skeletal muscle as generators of mechanical force. However, the influence of insulin- like growth factor-I (IGF-I), a master regulator of skeletal muscle cells, on plectin and MACF1 in skeletal muscle cells has not been demonstrated. The effect of IGF-I on plectin and MACF1 gene expression was investigated by treating differentiated C2C12 murine skeletal muscle cells with 20 ng/ml of IGF-I at different time points. The IGF-I treatment increased plectin protein expression in a dose-dependent manner. The mRNA level of plectin was measured by real-time quantitative PCR to determine if plectin induction was regulated pretranslationally. IGF-I treatment resulted in a very rapid induction of plectin mRNA transcript in C2C12 myotubes. Plectin mRNA increased by 140 and 180% after 24 and 48 hours of IGF-I treatment, respectively, and returned to the control level after 72 hours of IGF-I treatment. MACF1 mRNA increased 86 and 90% after 24 and 48 hours of IGF-I treat-ment, respectively, and returned to the control level after 72 hours of IGF-I treatment. These results suggested that the plectin gene is regulated pretranslationally by IGF-I in skeletal muscle cells. In conclusion, IGF-I induces a rapid transcriptional modification of the plectin and MACF1 genes in C2C12 skeletal muscle cells and has modulating effects on a cytolinker protein as well as on contractile proteins.