• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.231-237
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• 2011

A gene encoding a putative alanine racemase in Xanthomonas. oryzae pv. oryzae was cloned, expressed and characterized. Expression of the cloned gene was performed in Escherichia coli BL21(DE3)pLys using a pET-21(a) vector harbouring $6{\times}histidine$ tag. Purification of the recombinant alanine racemase by affinity chromatography resulted in major one band by sodium dodecyl sulfate polyacryl amide gel electrophoresis analysis, showing about 45 kDa of molecular weight. The alanine racemase gene, cloned in this experiment, appears to be constitutively expressed in X. oryzae, as analyzed by reverse transcriptase polymerase chain reaction. The enzyme was the most active toward L-alanine and secondly D-alanine, showing a racemic reaction, thus the enzyme is considered as an alanine racemase. The enzyme was considerably activated by addition of pyridoxal-5-phosphate (PLP), showing that 75% increase in activity was observed at 0.3 mM, compared with control. D-Cysteine as well as L-cysteine significantly inhibited the enzyme activity. The inhibitions by cysteines were more prominent in the absence of PLP, showing 9 and 5% of control activity at 2 mM of addition, respectively. The enzyme was the most active at pH 8.0 and more stable at alkaline pHs than acidic pH condition.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.182-183
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• 2014

Hemispherical dimples with diameter, ø=$60{\mu}m$ and depth, d= $30{\mu}m$ were created on the metal and ceramics surfaces using INYA 10 watt Laser of 1064 nm wavelength. This study reports the influence of dimple pitch on friction and wear behavior rather than dimple size, depth and density. LST was performed on the specimens with dimple pitch and density in the range of 80 to-$200{\mu}m$ and 44 to 7 %, respectively. Surface topography was analyzed by using roughness measurement, scanning electron microscopy (SEM), and optical microscopy. Friction and wear characteristics were analyzed on textured surfaces at lubricating environment to observe the effect of surface texturing on reduction of friction and wear. Reduction on coefficient of friction was achieved by more than 70% due to the dual behavior of dimples as wear (debris) traps and lubricant reservoirs. Wear reduced significantly for the textured surface as compared to the polished surface. Moreover, the friction coefficient of the textured specimens reduced with increasing load and speed which may be attributed to the transition of lubrication regime.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.192-196
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• 2010

This paper describes the effects of modified sulfur polymer content on the compressive strength and chemical resistance of Portland cement concrete with and without the modified sulfur polymer. The Portland cement concrete which contained modified sulfur had much higher strength than the Portland cement concrete without modified sulfur, workability is stabled at $55^{\circ}C$. Alkali tolerance test was evaluated by immersing these concrete specimens in 13 % $CaCl_2$ solutions. In the alkali tolerance test, the resistance of Portland cement concrete with modified sulfur to $CaCl_2$ increased compared with Portland cement concrete without modified sulfur.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.41-41
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• 2023

Red pepper (Capsicum annuum L.) is one of the most consumed vegetable worldwide. In this study, we tried to suggest the possibility of Cheongyang pepper as a functional cosmetic material by identifying the physiological activity, especially antioxidant and whitening effects of Cheongyang pepper through bibliometric analysis and experimental studies. A bibliometric analysis was performed through co-word analysis of 8,892 papers retrieved from SCOPUS. 4 research fields were obtained by cluster mapping from VOSviewer software, among which we noted the antioxidant activity of extracts from Capsicum annum L.. Phenol as a useful ingredient of Cheongyang pepper was analyzed using HPLC (high-performance liquid chromatography). Antioxidant and whitening effects were evaluated by measuring DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, hydrogen peroxide scavenging activity, and tyrosinase inhibitory activity. Cheongyang pepper extract showed contents of 0.106 ± 0.01 and 0.105 ± 0.02 mg/g, respectively, in the order of gallic acid and protocatechuic acid. The extract exhibited 56.95% DPPH scavenging activity and 43.97% hydrogen peroxide scavenging activity at a concentration of 1,000 ㎍/ml. In addition, 1,000 ㎍/ml of the extract inhibited tyrosinase activity by 52.44% and 42.61%, respectively in a whitening efficacy test using L-tyrosine and L-DOPA (L-3,4- dihydroxyphenylalanine) as substrates. These results suggest that Cheongyang pepper extract and its active ingredients have antioxidant and whitening effects, and the possibility of future development as a whitening functional cosmetic material.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2899-2905
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• 2011

We have demonstrated that TPyPA can be used as an efficient multi-functional material for OLEDs; hole transporting material (HTL), blue and white-light emitter. The device based on TPyPA as the HTL exhibited an external quantum efficiency of 1.7% and a luminance efficiency of 4.2 cd/A; these values are 40% higher than the external quantum efficiency and luminance efficiency of the NPD-based reference device. The device based on TPyPA as a blue-light emitter exhibited an external quantum efficiency of 4.2% and a luminance efficiency of 5.3 $cdA^{-1}$ with CIE coordinates at (0.16, 0.14), the device based on TPyPA as a white-light emitter exhibited an external quantum efficiency of 3.2% and a luminance efficiency of 7.7 $cdA^{-1}$ with CIE coordinates at (0.33, 0.39). Also, TPyPA-based organic solar cell (OSC) exhibited a maximum power conversion efficiency of 0.35%. TPyPA-based organic thin-film transistors (OTFTs) exhibited highly efficient field-effect mobility (${\mu}_{FET}$) of $1.7{\times}10^{-4}cm^2V^{-1}s^{-1}$, a threshold voltage ($V_{th}$) of -15.9 V, and an on/off current ratio of $8.6{\times}10^3$.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.203-209
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• 2011

The cement industry is expected to face a major set-back in the near future due to its large energy consumption and $CO_2$ production, causing global warming. In order to overcome these environmental problems, this research has bee carried out to find a cement substitute material. One possible cement substitute material is Zeolite cement. In this study, the materialistic characteristics of Zeolite cement mortar were evaluated. Natural Zeolite cement mortar was prepared using alkali activation (NaOH) instead of water ($H_2O$) to determine achievable strength and appropriate mixing ratio. Based on the mixing ratio, functional material was added to alkali active agent to harden Zeolite mortar to develop a highly functional construction material. The study result showed that pure Zeolite cement mortar achieved compressive strength of 42 MPa in 7 days depending on the mixing amount of alkaline catalyst and the hardening temperature, showing high efficiency and possibility as a new construction material.

• Fashion & Textile Research Journal
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• v.22 no.5
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• pp.628-638
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• 2020

This study develops a cool-touch functional Dancesport top for middle-aged women by using cool-touch materials in areas where surface temperature becomes high after exercise. The post-exercise surface temperature of the developed research product was compared and analyzed. In addition, subjective evaluation of cool-touch as well as appearance and movement evaluations were performed. The results are as follows. In designing the research product, a detachable neckband was made using highly-preferred hydrated polymer crystals. A material with high moisture absorption speed was also used in F1, S1, under arm and B5, while a material with good thermal conductivity was used in other parts of the bodice. Deodorant tape with antibacterial and deodorant effects was incorporated in the armpit for additional comfort. As for wear evaluation of the research product, significant differences were found in 10 areas using a material with high moisture absorption speed to compare and analyze the post-exercise surface temperatures of the clothing. The temperature difference between the compared top and the research product in the neckband area was 9.16℃, demonstrating clear cool-touch function in using cool-touch material. In the subjective evaluation of cool-touch function, the results showed high scores when asked about the efficiency of the detachable neckband and the ease of movement when wearing the product. In the appearance evaluation, significant differences were found in 11 items, including redundant folds, tightfit, fit, and design line. The overall mean score of the movement evaluation was 4.6, indicating excellent function for movement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.584-592
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• 2012

Room temperature powder spray in vacuum process, so called Aerosol deposition (AD) is a room temperature (RT) process to fabricate thick and dense ceramic films, based on collision of solid ceramic particles. This technique can provide crack-free dense thin and thick films with thicknesses ranging from sub micrometer to several hundred micrometers with very fast deposition rates at RT. In addition, this technique is using solid particles to form the ceramic films at RT, thus there is few limitation of the substrate and easy to control the compositions of the films. In this article, we review the progress made in synthesis of piezoelectric thin/thick films, multi-layer structures, NTC thermistor thin/thick films, oxide electrode thin films for actuators or sensor applications by AD at Korea Institute of Materials Science (KIMS) during the last 4 years.

• Current Applied Physics
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• v.18 no.11
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• pp.1410-1414
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• 2018

Magnetic nanoparticles (MNP) have attracted considerable interest in many fields of research and applied science due to their impressive properties. In the past, especially biomedical problems have promoted the development of MNPs. For technical applications e.g. wastewater treatment and absorption of electromagnetic waves, the existing synthesis approaches are too expensive and/or the producible quantities are too low. In this work we present a method for simple preparation of size-controlled magnetic iron oxide nanoparticles by electroerosion dispersion (EED) of carbon steel in water. We describe the synthesis method, the laboratory installation and discuss the structural, chemical and electromagnetic properties of the synthetized EED powders as well as their applicability for microwave absorption compared to other available ferrite powders.

• Food Science and Preservation
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• v.8 no.2
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• pp.224-230
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• 2001

To develop a material for functional food, the fraction Ⅰ,II and Ⅲ of onion extract were separated by Sephadex LH-20 column. The revealed purification levels of each fraction were 5.2%-6.5%, 12.2%-14.5% and 82.6%-86.7%, respectively. A functional activity test was performed with fraction Ⅲ. The ACE inhibition activity was about 50% at 5mg and about 80% at 10mg. The XOase inhibition activity of Korean Changnyong Daego was 84%, which was the highest. At the experiment of tyrosinase inhibition was detected 21-36% at 10mg. The cholesterol dose in mice blood was as low as low as 79$\pm$5(mg/100 mL) after the intake of fraction Ⅲ. Cholestrol dose in liver was decreased to below 50%. The results show that Sephadex LH-20 column method was very useful as a fraction method for the development of functional food material nsing onions.