• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.53-61
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• 2014

This study was investigated the antimicrobial activity of glutaraldehyde cross-linked glucosamine. Glutaraldehyde was used as a cross-linker which specifically combines an amine-group of molecules. To optimize the mixing ratio of glutaraldehyde and glucosamine, mixing ratio was set up 1:1, 2:1, 3:1 and 0.5:1 in molarity, respectively. The optimum mixing ratio of glucosamine and glutaraldehyde was found to be 3:1 using thin layer chromatography based on the production of complex. Glucosamine-glutaraldehyde cross-linked complex (Ggcc) revealed significant antimicrobial activity toward PWG than F1, both microbial strains were isolated from porcine semen as antibiotics resistance bacteria (ARB). These results clearly demonstrate that Ggcc has potential bactericidal activity toward ARB in porcine semen.

• KSBB Journal
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• v.30 no.1
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• pp.1-10
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• 2015

Nanomaterial-based artificial enzymes (Nanozymes) have attracted recent attention because of their unique advantageous characteristics such as excellent robustness and stability, low-cost production by facile scale-up, and longterm preservation capability that are critically required as an alternative to natural enzymes. These nanozymes exhibit natural enzyme-like activity, and they have been applied to diverse kinds of detection methods for disease-associated biomolecules such as DNAs, proteins, cells, and small molecules including glucose. To highlight the progress in the field of disease diagnostics using nanozyme, this review discusses many nanozyme-based detection methods categorized by the types of target biomolecules. Finally, we address the current challenges and perspectives for the widespread utilization of nanozyme-based disease diagnostics.

• KSTLE International Journal
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• v.8 no.2
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• pp.26-28
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• 2007

Si(100) surfaces were topographically modified i.e. the surfaces were patterned at micro-scale using photolithography and DRIE (Deep Reactive Ion Etching) fabrication techniques. The patterned shapes included micro-pillars and microchannels. After the fabrication of the patterns, the patterned surfaces were chemically modified by coating a thin DLC film. The surfaces were then evaluated for their friction behavior at micro-scale in comparison with those of bare Si(100) flat, DLC coated Si(100) flat and uncoated patterned surfaces. Experimental results showed that the chemically treated (DLC coated) patterned surfaces exhibited the lowest values of coefficient of friction when compared to the rest of the surfaces. This indicates that a combination of both the topographical and chemical modification is very effective in reducing the friction property. Combined surface treatments such as these could be useful for tribological applications in miniaturized devices such as Micro-Electro-Mechanical-Systems (MEMS).

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.417-429
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• 2018

Background: The objective of this study was to make colloidal dispersions of the active compounds of radix of Angelica gigas Nakai that could be charaterized as nano-composites using hot melt extrusion (HME). Food grade hydrophilic polymer matrices were used to disperse these compound in aqueous media. Methods and Results: Extrudate solid formulations (ESFs) mediated by various HPMCs (hydroxypropyl methylcelluloses) and Na-Alg polymers made from ultrafine powder of the radix of Angelica gigas Nakai were developed through a physical crosslink method (HME) using an ionization agent (treatment with acetic acid) and different food grade polymers [HPMCs, such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in the HP55-mediated extrudate solid formulation (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (${\Delta}H=10.62J/g$) of glass transition temperature (Tg) in the HP55-ESF than in the other formulations. Infrared fourier transform spectroscopy (FT-IR) revealed that new functional groups were produced in the HP55-ESF. The content of phenolic compounds, flavonoid (including decursin and decursinol angelate) content, and antioxidant activity increased by 5, 10, and 2 times in the HP55-ESF, respectively. The production of water soluble (61.5%) nano-sized (323 nm) particles was achieved in the HP55-ESF. Conclusions: Nano-composites were developed herein utilizing melt-extruded solid dispersion technology, including food grade polymer enhanced nano dispersion (< 500 nm) of active compounds from the radix of Angelica gigas Nakai with enhanced solubility and bioavailability. These nano-composites of the radix of Angelica gigas Nakai can be developed and marketed as products with high therapeutic performance.

• Korean Journal of Materials Research
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• v.23 no.12
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• pp.745-756
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• 2013

Recent rapid development of the Chinese economy based on science and technology is challenging Korean industries and economy. Since the driving force for this rapid development of China is known to be scientific technologies, the purpose of this research is to confirm the current status of Chinese scientific research in the field of "Materials Science and Engineering" and propose a strategy for competition with China. Even though there are numerous journals of "Materials Science and Engineering", the 10 most popular journals with high impact factors were selected to cover general materials, nano materials, bio materials, and electronic materials. It was found that the number of scientific papers written by Chinese scientists for the materials field in the 10 journals was slowly increasing from the year 2000 until 2005, but has been rapidly increasing since 2005. This research found that Chinese research activities in the traditional metallic materials and nano materials have tremendously increased to occupy around 30 % or more papers published in several major journals related with materials science and engineering. On the other hand, bio materials and electronic materials research has not been pursued so actively; however, very recently the number of publications in these fields is also beginning to increase. To compete with this tremendously growing Chinese scientific development, Korea should have a policy of "selection and concentration" in materials-related fields, including basic science in nano, bio, and electronic materials.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.81-89
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• 2009

In this experimental study, the effects of clean alternative fuels compatible with diesel combustion on nano-sized particle emission characteristics were investigated in a 0.5L auto-ignited single-cylinder engine with a compression ratio of 15. Because the number concentration of nano-sized particles emitted by automotive engine, that are suspected of being hazardous to human health and environment, might increase with engine fuel considerably and recently attracted attention. So a ultra-low sulfur diesel(ULSD), BD100(100% bio-diesel) and Di-Methyl Ether(DME) fuels used for this study. And, as a particle measuring instrument, a fast-response particle spectrometer (DMS 500) with heated sample line was used for continuous measurement of the particle size and number distribution in the size range of 5 to 1000nm (aerodynamic diameter). As this research results, we found that this measurements involving the large proportion of particles under size order of 300nm and number concentration of $4{\times}10^9$ allowed a single or bi-modal distribution to be found at different engine load conditions. Also the influence of oxygen content in fuel and the catalyst could be a dominant factor in controlling the nano-sized particle emissions in auto-ignited engine.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.441-446
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• 2007

Outcoupling efficiency of the OLED device is improved by incorporating both a microlens array and a diffractive grating pattern. The microlens array improves the light transmission at the interface of glass and air, and the diffractive grating outcouples the guided mode propagating at the waveguide, which consists of ITO and organic layers. By using the PDMS soft mold imprinting method, the microlens array is fabricated on the glass substrate. The diffractive grating pattern is directly fabricated on the ITO surface by using laser interferometry. A microlens array with a diameter of $10{\mu}m$ improves the light coupling efficiency by 22%. The diffractive grating made of TSMR photoresist enhances the luminance power efficiency by 41% at a current density of $20mA/cm^2$.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.11-17
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• 2013

Purpose: To improve glasses temple's insert processibility of CA/PEG blend, triacetin with higher specific heat values in the processing temperature range is used as second plasticizer. Methods: The total amount of plasticizer is fixed at 30 wt% by CA. To determine optimal CA/PEG/triacetin blend for glasses frame, blends with different composition ratio were examined by various analysis: thermal properties, mechanical properties, glossiness. Results: Specific heat of the CA/PEG blend increased as the content of triacetin. In CA/PEG/triacetin blends, as triacetin concentration is increased, glass transition temperature is decreased and heat conservation rate of composites is increased. Furthermore, CA/PEG/triacetin blend exhibited higher mechanical properties and similar gloss characterization with CA/PEG blend. Conclusions: It is possible to improve the processibility inserting metal support to CA temple through varying the weight ratio of PEG/triacetin. The extruded sheets of CA/PEG/triacetin blend had better glossiness and mechanical properties than those of CA/PEG blend.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.13-19
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• 2011

Purpose: The purpose of this study was to assess characterize overseas company's Cellulose acetate glasses frame sheets (overseas company's CA sheet) Also, the optimum content of plasticizer and melt extrusion condition of industrial CA resin were established for appropriate glasses frame. Methods: Overseas company's Cellulose acetate glasses frame sheets (overseas company's CA sheet) were characterized by $^1H$-NMR, GPC, and TGA. Also, the optimum content of plasticizer and melt extrusion condition of industrial CA resin were established. Results: The plasticizer of overseas company's CA sheet measured by $^1H$-NMR was diethyl phthalate, and its content was measured 30 wt% by TGA. Also, industrial CA resin showed enough melting behavior in the range of 190~200$^{\circ}C$. Compared to overseas company's CA sheet's tensile strength value of 2.2~2.8 kgf/$mm^2$, industrial CA resin exhibited sufficient tensile strength value of 2.3 kgf/$mm^2$ for glasses frame. Conclusions: Industrial CA resin with 30 wt% plasticizer content would be a promising material for glasses frame prepared by melt extrusion to replace China CA sheet.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.1-10
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• 2012

Purpose: Cellulose acetate (CA) was blended with polyethyleneglycol (PEG) having different molecular weight at various mixing conditions to enhance melt-processibility of CA, which might prevent the harmful effect resulted from the introduction of phthalic plasticizer. Methods: To establish optimal plasticizing conditions, CA/PEG blends were examined under various plasticizing conditions: PEG concentration, molecular weight of PEG, and plasticzing temperature. Mechanical properties of the CA/PEG blends, as well as migration and exudation of the PEG, were performed in order to evaluate the efficiency of plasticization. Results: Compared to industrial CA resin plasticized by diethyl phthalate, CA/PEG blends exhibited similar thermal plasticization. It was established that the optimum condition was to blend 30~40 phr PEG with molecular weight 400 at $175{\sim}180^{\circ}C$. CA/PEG blend showed superior glassness, PEG stability, and mechanical properties. Conclusions: CA/PEG blends would be a eco-friendly glasses frame to substitute traditional CA glasses frame prepared phthalate plasticizers.