• Geomechanics and Engineering
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• v.12 no.5
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• pp.739-752
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• 2017

This study was intended to evaluate the improved strength of the ground by applying the bio grouting method to a loose sandy ground. The injection material was prepared in the form of cement-like powder, with the bio injection material produced by microbial reactions. The grouting test was conducted under the conditions similar to the field where the bio injection material can be applied. In addition, the injection materials (cement and sodium silicate No. 3) used for Labile Waterglass (LW) method and the conventional grouting methodwere prepared through a two-solution one-step process. The injection into the specimens was done at a pressure of 150 kPa and then, with a bender element, their moduliof elasticity were measured on the 7th, 14th, 21st and 28th curingdays to analyze their strengths according to the duration of curing. It was confirmed that in all injection materials the moduli of elasticity increased over time. In particular, when 30% of the bio injection material was added to 100% cement, the modulus of elasticity tended to increase by about 15%. This confirmed that the applicability became higher when the bio injection material was used in place of the conventional sodium silicate.

• KSBB Journal
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• v.30 no.6
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• pp.268-274
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• 2015

3D printing technology has been used in various fields such as materials science, manufacturing, education, and medical field. A number of research are underway to improve the 3D printing technology. Recently, the use of 3D printing technology for fabricating an artificial tissue, organ and bone through the laminating of cell and biocompatible material has been introduced and this could make the conformity with the desired shape or pattern for producing human entire organs for transplantation. This special printing technique is known as "3D Bio-Printing", which has potential in biomedical application including patient-customized organ out-put. In this paper, we describe the current 3D bio-printing technology, and bio-materials used in it and present it's practical applications.

• BMB Reports
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• v.46 no.5
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• pp.244-251
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• 2013

Lignocellulosic materials are commonly used in bio-$H_2$ production for the sustainable energy resource development as they are abundant, cheap, renewable and highly biodegradable. In the process of the bio-$H_2$ production, the pretreated lignocellulosic materials are firstly converted to monosaccharides by enzymolysis and then to $H_2$ by fermentation. Since the structures of lignocellulosic materials are rather complex, the hydrolysates vary with the used materials. Even using the same lignocellulosic materials, the hydrolysates also change with different pretreatment methods. It has been shown that the appropriate hydrolysate compositions can dramatically improve the biological activities and bio-$H_2$ production performances. Over the past decades, hydrolysis with respect to different lignocellulosic materials and pretreatments has been widely investigated. Besides, effects of the hydrolysates on the biohydrogen yields have also been examined. In this review, recent studies on hydrolysis as well as their effects on the biohydrogen production performance are summarized.

• Journal of the Korea Furniture Society
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• v.29 no.1
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• pp.18-23
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• 2018

The purpose of this study was to develop wood pots for create Optimum environment of plant growth using unused wood. to prove this, we examined the effects of cycle of water supply and nutrient concentration in wood pots on plant germination rate and growth factors (leaf number, stem diameter and length). The results are as follows. 1) The growth rate was higher at once of 2 days watering period. This suggests that the growth of the plants was better than that of the less water because the larch pots itself has the water retention capacity inside. 2) Germination rate and growth rate were better than other treatment groups when the concentration of nutrient solution was 0.5%. 3) Nitrogen, available phosphoric acid, and potassium showed higher contents than the nutrient - treated soil at 0.5% concentration of nutrient solution. This indicates that the nutrient solution absorbed from the larch affected the soil and plant growth in the inside.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.39-50
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• 2007

The purpose of this study was to investigate the physico-mechanical properties and characteristics on reduction of formaldehyde and total volatile organic compound (TVOC) emission from particleboard (PB) with added volcanic pozzolan. Pozzolan was added as a scavenger at the level of 1, 3, 5, and 10 wt.% of urea formaldehyde (UF) resin for PB manufacture. The moisture content, density, thickness swelling, water absorption and physical properties of PBs were examined. Three-point bending strength and internal bond strength were determined using a universal testing machine. Formaldehyde and TVOC were determined by desiccator and 20L small chamber methods. With increasing pozzolan content the physical and mechanical properties of the PBs were not significantly changed, but formaldehyde and TVOC emissions were decreased. Because pozzolan has a rough and irregular surface with porous form, it can be used as a scavenger for PBs at a content up to 10 wt.% without any detrimental effect on the physical and mechanical properties.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1806-1808
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• 2014

We report the successful preparation of gold nanoparticles (Au NPs) using a novel electroreduction process, which is simple, fast, and environmentally friendly (toxic chemicals such as strong reducing agents are not required). Our process allows for the mass production of Au NPs and adequate particle size control. The Au NPs prepared show high biocompatibility and are non-toxic to healthy human cells. By applying radio-frequency (RF) ablation, we monitored the electro-hyperthermia effect of the Au NPs at different RFs. The Au NPs exhibit a fast increase in temperature to $55^{\circ}C$ within 5 min during the application of an RF of 13 MHz. This temperature rise is sufficient to promote apoptosis through thermal stress. Our work suggests that the selective Au NP-mediated electro-hyperthermia therapy for tumor cells under an RF of 13 MHz has great potential as a clinical treatment for specific tumor ablation.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.291-298
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• 2013

Conjugated linoleic acid methylester was synthesized through isomerization of linoleic acid methylester by using heterogeneous catalysts. As for heterogeneous catalysts, Ni supported zeolite type catalysts were used. H zoelite Y (HY) were ion exchanged with KCl aqueous solution to synthesize K zeolite Y (KY), and with impregnation method, Ni supported zeolite catalysts were synthesized. Catalysts were used after pre-treatment by using hydrogen. HY catalysts showed a high conversion at low temperatures; but a low selectivity for conjugation reaction. KY catalysts showed a low conversion at low temperatures; but a similar conversion with HY catalysts at high temperatures while a high selectivity at low temperatures. As a result, 4 wt% Ni/KY720 recorded the high conjugation yield of 63.4% at 220.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.143-149
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• 2015

This experiment was conducted to evaluate the synergistic effects of vitamin C and E on methylmercury (MeHg) toxicity in juvenile olive flounder Paralichthys olivaceus. In a $3{\times}3$ factorial design, 9 experimental diets containing three different vitamin C (0, 200 or 400 mg/kg diet in the form of l-ascorbyl-2-monophosphate) and vitamin E (0, 100 or 200 mg/kg diet in the form of dl-${\alpha}$-tocopheryl acetate) levels with the Hg toxicity level (20 mg/kg diet in the form of MeHg) were formulated. Triplicate groups of fish averaging $2.3{\pm}0.05g(mean{\pm}SD)$ were fed one of the 9 diets in a flow through system for 8 weeks. Fish fed 400 mg vitamin C/kg diet with 100 or 200 mg vitamin E/kg diet showed significantly (P < 0.05) higher weight gain (WG) than did fish fed the other diets. Fish fed 400 mg vitamin C/kg diet at all vitamin E levels and those which fed vitamin C and E equally at a rate of 200 mg/kg diet showed significantly (P < 0.05) higher feed efficiency (FE), specific growth rate (SGR) and protein efficiency ratio (PER) than did fish fed the other diets. Fish fed 200 and 400 mg vitamin C/kg diet exhibited significantly (P < 0.05) lower Hg concentration in their muscle as well as kidney than did fish fed the other diets. Therefore, these results clearly indicated that the synergistic effects of these two vitamins on MeHg toxicity by supplementing dietary vitamin C (200 and 400 mg/kg diet) with vitamin E (100 and 200 mg/kg diet) in juvenile olive flounder.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.759-765
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• 2013

The gene encoding squalene synthase (SQS) of the lipid-producing heterotrophic microalga Aurantiochytrium sp. KRS101 was cloned and characterized. The krsSQS gene is 1,551 bp in length and has two exons and one intron. The open reading frame of the gene is 1,164 bp in length, yielding a polypeptide of 387 predicted amino acid residues with a molecular mass of 42.7 kDa. The deduced krsSQS sequence shares at least four conserved regions known to be required for SQS enzymatic activity in other species. The protein, tagged with $His_6$, was expressed into soluble form in Escherichia coli. The purified protein catalyzed the conversion of farnesyl diphosphate to squalene in the presence of NADPH and $Mg^{2+}$. This is the first report on the characterization of an SQS from a Thraustochytrid microalga.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.156-163
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• 1992

Bacillus sp. was isolated from soil for its strong activity of cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19). The enzyme was purified by gel filtration and anion exchange column chromatography using FPLC. The purified enzyme exhibited its maximum CGTase activity in the pH range of 6~8 and the temperature range of 50~$70^{\circ}C$. The molecular weight was estimated as 114,000 by SDS-PAGE. The isoelectric point of the enzyme was 4.3. The CGTase of Bacillus sp. E l produced $\beta$-cyclodextrin mainly and did not produce a-cyclodextrin. The product ratio of $\beta$-cyclodextrin to $\gamma$-cyclodextrin was 7:l.