• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Molecules and Cells
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• v.25 no.1
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• pp.112-118
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• 2008

Laccases are multicopper-containing oxidases that catalyze the oxidation of many aromatic compounds with concomitant reduction of oxygen to water. Interest in this enzyme has arisen in many fields of industry, including detoxification, wine stabilization, paper processing, and enzymatic conversion of chemical intermediates. In this study, we cloned a laccase gene (GLlac1) from the white-rot fungus Ganoderma lucidum. The cloned gene consists of 4,357 bp, with its coding region interrupted by nine introns, and the upstream region has putative CAAT and TATA boxes as well as several metal responsive elements (MREs). We also cloned a full-length cDNA of GLlac1, which contains an uninterrupted open reading frame (ORF) of 1,560 bp coding for 520 amino acids with a putative 21-residue signal sequence. The DNA and deduced amino acid sequences of GLlac1 were similar but not identical to those of other fungal laccases. GLlac1 was released from the cells when expressed in P. pastoris, and had high laccase activity. In addition, GLlac1 conferred antioxidative protection from protein degradation, and thus may be useful in bio-medical applications.

• Polymer(Korea)
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• v.26 no.3
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• pp.410-414
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• 2002

The late transition Pd catalyst of low oxophilicity that has ferrocene -based diimine ligand for stabilization of center metal had been synthesized and applied for the polymerization of methyl methacrylate (MMA). In the presence of triisobutylaluminium (TIBA) for impurity scavenger, the effects of polymerization temperature and [TIBA]/[Pd] mole ratio on the yield and glass transition temperature ($T_g$) of PMMA had been examined. For 40~$50^{\circ}C$ of polymerization temperature and 2000~3000 of [TIBA]/[Pd] mole ratio, higher polymer yields were obtained. It was observed that ($T_g$) of PMMA is almost independent to the polymerization temperature but influenced by the [TIBA]/[Pd] mole ratio. With the examination of($T_g$) of PMMA with the structure of polymer, it had been found that T$_{g}$ of PMMA exhibits a linear relationship with the isotacticity of polymer.r.

• Journal of Korean Neurosurgical Society
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• v.40 no.6
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• pp.412-418
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• 2006

Objective : The safety of titanium metal cages in tuberculous spondylitis has not been investigated. We evaluated the outcome and complications of titanium mesh cages for reconstruction after thoracolumbar vertebrectomy in the tuberculous spondylitis. Methods : There were 17 patients with 18 operations on the tuberculous spondylitis in this study. Sixteen patients were operated with anterior corpectomy and reconstruction with titanium mesh cage followed by posterior transpedicular screw fixations on same day, two pateints were operated by either anterior or posterior approach only. After the affected vertebral body resection and pus drainage from the psoas muscle, titanium mesh cage, filled with morselized autogenous bone, was inserted. All the patients had antituberculosis medication for 18 months. The degree of kyphosis correction and the subsidence of cage were measured in the 15 patients available at a minimum of 2 years. Outcome was assessed with various cross-sectional outcome measures. Recurrent infection was identified by serial ESR[Erythrocyte Sedimentation Rate] and CRP[Cross Reactive Protein]. Results : There was no complication from the use of a titanium mesh cage. Recurrent infection was not detected in any case. Average preoperative of $9.2^{\circ}$ was reduced to $-2^{\circ}$ at immediate postoperative period, and on final follow up period kyphotic angle was measured to be $4.5^{\circ}$. Postoperatively, subsidence was detected in most patients especially at ambulation period, however further subsidence was prevented by the titanium mesh cage. Osseous union was identified in all cases at the final follow-up. Conclusion : The cylindrical mesh cage is a successful instrument in restoring and maintaining sagittal plane alignment without infection recurrence after vertebrectomy for tuberculous spondylitis.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.348-355
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• 2012

Ferulic and caffeic acids are hydroxycinnamic acid derivatives, which are potent plant antioxidants. Their free radical scavenging abilities in aqueous solution exposed to DPPH radical, and chemical stabilities against oxidative stress like high temperature and metal ion, were evaluated. To improve the stability of ascorbic acid solution, ferulic acid or caffeic acid was incorporated into ascorbic acid solution. Stability improvement of ascorbic acid was verified through $SC_{50}$ value change according to storage time. Ascorbic acid in combination with ferulic acid or caffeic acid was encapsulated with high efficiency inside BGsome. In this form, its stability was remarkably enhanced compared to that in free aqueous solution.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.356-361
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• 2013

Lead (II) ion selective poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore as a sulfur containing sensing material is successfully developed. The electrode exhibits good linear response of 25.6 mV / decade (at $20{\pm}0.2^{\circ}C$, r2=0.995) within the concentration range of $1.0{\times}10^{-1}{\sim}4.0{\times}10^{-7}$ M Pb (II). The composition of this electrode was Ionophore : PVC : dioctylphthalate : potassiumtetrakis(4-chlorophenyl)borate : Oleic acid = 5.0 : 20.0 : 25.0 : 4.0 : 5.0. When we consider the results of using different composition electrodes based on only one potassiumtetrakis(4-chlorophenyl)borate or Oleic acid liphophlic additive, poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore with potassiumtetrakis(4-chlorophenyl)borate and Oleic acid liphophlic additive had the best result in response characteristics. The electrode shows good selectivity for lead (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.0 ~ 7.0 and their standard deviation in the measured emf differences was ${\pm}2.94$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-2}$ M and ${\pm}2.82$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-3}$ M. Their stabilization time was less than 710 s. and response time was less than 16 s.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.104-112
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• 2002

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Thyristor Controlled Series Capacitor(TCSC) using Geletic Algorithm(GA). A TCSC meddle consists of a stories capacitor and a parallel path with a thyristor valve and a series inductor. Also in in parallel, as is typical with series capacitor applications, is a metal-oxide varistor(MOV) for overvoltage protection. The proposed PSS parameters are optimized using GA in order to maintain optimal operation of TCSC which is expected to be applied in transmission system to achieve a number of benefits under the various operating conditions. In order to verify the robustness of the proposed method, we considered the dynamic response of angular velocity deviation and terminal voltage deviation under a power fluctuation and rotor angle variation.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.522-533
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• 2014

Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of $Ag^+$ ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of $Ag^+$ ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

• Advances in nano research
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• v.3 no.2
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• pp.97-109
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• 2015

Citrate ion is a commonly used reductant in metal colloid synthesis, undergoes strong surface interaction with silver nanocrystallites. The slow crystal growth observed as a result of the interaction between the silver surface and the citrate ion makes this reduction process unique compared to other chemical and radiolytic synthetic methods. The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of citrate coated Ag nanoparticles (CAgNPs) are scant. Herein, we have isolated biofilm causative bacteria and fungi from drinking water PVC pipe lines. Stable CAgNPs were prepared and the formation of CAgNPs was confirmed by UV-visible spectroscopic analysis and recorded the localized surface plasmon resonance of CAgNPs at 430 nm. Fourier transform infrared spectroscopic analysis revealed C=O and O-H bending vibrations due to organic capping of silver responsible for the reduction and stabilization of the CAgNPs. X-ray diffraction micrograph indicated the face centered cubic structure of the formed CAgNPs, and morphological studies including size (average size 50 nm) were carried out using transmission electron microscopy. The hydrodynamic diameter (60.7 nm) and zeta potential (-27.6 mV) were measured using the dynamic light scattering technique. The antimicrobial activity of CAgNPs was evaluated (in vitro) against the isolated fungi, Gram-negative and Gram-positive bacteria using disc diffusion method and results revealed that CAgNPs with 170ppm concentration are having significant antimicrobial effects against an array of microbes tested.

• Clinics in Shoulder and Elbow
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• v.20 no.3
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• pp.153-161
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• 2017

Background: This study was conducted to compare the clinical and radiological outcomes of the locking hook plate fixation (HP) technique and the single tight rope (TR) technique applied for acute high-grade acromioclavicular (AC) joint separations. Methods: Between 2009 and 2014, 135 consecutive patients with acute AC joint separation Rockwood types III, IV, and V were subjected to surgical reconstruction. One hundred fourteen patients (84.4%) were available for retrospective evaluation. Of them, 62 and 52 were treated using the single TR group and clavicular HP group techniques, respectively. The visual analogue scale, Constant, American Shoulder and Elbow Surgeons (ASES), and Taft scores were used for clinical assessment. Postoperative shoulder range of motion was also assessed. An anteroposterior radiograph of the coracoclavicular distance (CCD) was obtained to evaluate the radiographic signs of recurrence. Results: The TR group patients had better Constant, ASES, and Taft scores than the HP group patients. The loss of reduction in terms of the CCD did not differ between groups. Subacromial osteolysis was observed in 34.6% of the cases in the HP group. However, there were no significant differences in the clinical outcomes between the patients with and without osteolysis in the HP group. Subcoracoid osteolysis, drill tunnel widening, and metal displacement were observed in 3.2%, 22.6%, and 4.8% of the cases in the TR group, respectively. Conclusions: The single TR technique was relatively more effective at treating acute high-grade AC joint injuries than the HP fixation technique (level of evidence: therapeutic; retrospective comparative study, Level III).