• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.5
• /
• pp.501-509
• /
• 2016

In this study, a flat-type photocatalytic reactor is applied under solar irradiation for simultaneous treatment of target pollutants: reduction of Cr(VI) to Cr(III) and oxidation of EDCs (BPA, EE2, E2). An immobilized type of photocatalyst was fabricated to have self-grown nanotubes on its surface in order to overcome limitations of powdery photocatalyst. Moreover, Ti mesh form was chosen as substrate and modified to have both larger surface area and photocatalyst content. Ti mesh was anodized at 50V and $25^{\circ}C$ for 30min in the mixed electrolytes ($NH_4F-H_2O-C_2H_6O_2$) and annealed at $450^{\circ}C$ for 2 hours in ambient oxygen to have anatase structure. Surface characterization was done with SEM and XRD methodologies. Fabricated NTT was applied to water treatment, and coexisting Cr(VI) and organics (EDCs) enhanced each other's reactions by scavenging holes and electrons and thus impeding recombination. Also, several experiments were conducted outdoor under direct sunlight and it was observed that both solar-tracking and applying modified photocatalyst were proven to enhance reaction efficiency.

• The Journal of Korean Medicine
• /
• v.36 no.1
• /
• pp.45-60
• /
• 2015

Objectives: The purpose of this study was to understand the status of reporting and characteristics of adverse drug reactions (ADRs) induced by herbal drugs and to make a suggestion for the domestic pharmacovigilance system on herbal medicine. Methods: We carried out a hospital-based observational study at Dongguk University Ilsan Oriental Hospital from April 2012 to December 2014. We reviewed all the herbal-drug-associated ADRs reports registered to the spontaneous ADR reporting system in electronic medical records of the hospital in the period. Results: We found out 101 reports including 163 herbal-drug-associated ADRs from 97 patients. Females (69.3%) outnumbered males and the most frequent age group was the 50s (44, 27.0%). No serious adverse event was observed. The most commonly reported ADR was gastro-intestinal system disorders (68, 41.5%) followed by skin-related disorders (42, 25.8%). Diarrhea (29, 17.8%) was the most frequently referred clinical manifestation. Most ADRs were induced by internal medicines (160, 98.2%) including manufactured (36, 22.1%) and self-prepared decoction (160, 76.1%). The pairs of Igi-hwan-diarrhea, gamiboa-tang-vomiting, and Magnoliae Flos-gastro-intestinal-system-related ADRs were observed twice each and the others appeared only once. Conclusions: We propose Korean government to take an initiative in national pharmacovigilance system for herbal medicine. To perform the surveillance on herbal drugs, the Association of Korean Medicine (AKOM) should set up a nationwide network by designating centers connecting the Korean medical hospitals, local Korean medicine clinics, and the public health centers. The government and AKOM should also educate and encourage them to understand the pharmacovigilance system and report the ADRs actively.

• Journal of Powder Materials
• /
• v.17 no.3
• /
• pp.216-222
• /
• 2010

Self-standing $TiO_2$ nanotube arrays were fabricated by potentiostatic anodic oxidation method using pure Ti foil as a working electrode and ethylene glycol solution as electrolytes with small addition of $NH_4F$ and $H_2O$. The influences of anodization temperature and time on the morphology and formation of $TiO_2$ nanotube arrays were investigated. The fabricated $TiO_2$ nanotube arrays were applied as a photoelectrode to dye-sensitized solar cells. Regardless of anodizing temperature and time, the average diameter and wall thickness of $TiO_2$ nanotube show a similar value, whereas the thickness show a different trend with reaction temperature. The thickness of $TiO_2$ nanotube arrays anodized at $20^{\circ}C$ and $30^{\circ}C$ was time-dependent, but on the other hand its at $10^{\circ}C$ are independent of anodization time. The conversion efficiency is low, which is due to a morphology breaking of the $TiO_2$ nanotube arrays in manufacturing process of photoelectrode.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.8 no.1
• /
• pp.71-76
• /
• 2010

The electrorefining process, one of main processes which are composed of pyroprocess to recover the useful elements from spent fuel, and the domestic development of electrorefiner have been reviewed. The electrorefiner is composed of an anode basket containing reduced spent fuel such as uranium, transuranic and rare earth elements, and a solid cathode, which are in LiCl-KCl eutectic electrolyte. Oxidation (dissolution) reaction occurs on the anode and a pure uranium is electrochemically reduced (deposited) on the solid cathode. By application of graphite cathode, which has a self-scrapping characteristics for the uranium deposits, and a recovery of the fallen deposits by a screw conveyer, a high-throughput continuous electrorefiner with a capacity of 20 kgU/day has been developed.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.2
• /
• pp.335-341
• /
• 2017

The complexity of the bacterial recombination system is a barrier for the construction of bacterial mutants for the further functional investigation of specific genes. Several protocols have been developed to inactivate genes from the genus Pseudomonas. Those protocols are complicated and time-consuming and mostly do not enable easy construction of multiple knock-ins/outs. The current study describes a single and double crossover-recombination system using an optimized vector-free allele-exchange protocol for gene disruption and gene replacement in a single species of the family Pseudomonadaceae. The protocol is based on self-ligation (circularization) for the DNA cassette which has been obtained by overlapping polymerase chain reaction (Fusion-PCR), and carries an antibiotic resistance cassette flanked by homologous internal regions of the target locus. To establish the reproducibility of the approach, three different chromosomal genes (ncRNA31, rpoN, rpoS) were knocked-out from the root-associative bacterium Pseudomonas stutzeri A1501. The results showed that the P. stutzeri A1501 mutants, which are free of any plasmid backbone, could be obtained via a single or double crossover recombination. In order to optimize this protocol, three key factors that were found to have great effect on the efficiency of the homologous recombination were further investigated. Moreover, the modified protocol does not require further cloning steps, and it enables the construction of multiple gene knock-in/out mutants sequentially. This work provides a simple and rapid mutagenesis strategy for genome editing in P. stutzeri, which may also be applicable for other gram-negative bacteria.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.75-75
• /
• 2003

We report here the results on N-acetyl-N'-dimethylamide of proline (Ac-Pro-NM $e_2$) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level with the 6-31+G(d) basis set to investigate the conformational preference of polyproline depending on the cis/trans peptide bonds and down/up puckerings along the backbone torsion angle $\square$ in the gas phase, chloroform, and water. In the gas phase, Ac-Pro-NM $e_2$ has seven local minima of tFd, tFu, cFd, cFu, cAu, tAu, and cAd conformations. In particular, polyproline conformations tFd, tFu, cFd, and cFu are found to be more stable than $\square$-helical conformations cAu, tAu, and cAd. In contrast, Ac-Pro-NHMe has seven local minima of tCd, tCu, cBd, cAu, tAu, cFd, and cFu conformations. Conformations tCd and tCu are found to be most stable, which is ascribed to the intramolecular hydrogen bond between C=O of acetyl group and $N^{~}$ H of N'-methyl amide group. The stability of the cFd conformation (i.e., the polyproline I structure) in chloroform is somewhat increased, relative to that in water, although tFd and tFu conformations (i.e., the polyproline II structure) are dominate both in chloroform and water. The population of backbone conformations feasible in chloroform and water is consistent with the experiments. This work is supported by a Korea Research Foundation Grant (KRF-2002-041-C00129).

• Journal of the Korean Chemical Society
• /
• v.47 no.2
• /
• pp.104-108
• /
• 2003

The reaction of $[Cu(L)]Cl_2{\cdot}H_2O(L=3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^{1.18},0^{7.12}]docosane)$ with 2,5-pyridinedicarboxylate(pdc) led to the formation of $[Cu(L)(H_2O)](pdc){\cdot}6H_2O(1)$. The structure was characterized by X-ray crystallography and spectroscopic method. The coordination geometry around the copper atom is a distorted square-pyramid with four secondary amines of the macrocycle occupying the basal sites and a water molecule at the axial position. Intermolecular hydrogen bonds in 1 form a three-dimensional molecular network.

• Journal of Environmental Health Sciences
• /
• v.41 no.4
• /
• pp.268-276
• /
• 2015

Objectives: According to the 2007 Korea National Environmental Health Survey (KNEHS), some areas in the Gyeongsang Provinces showed very high blood mercury levels in adults. We conducted this project to investigate any related health effects in children due to mercury levels in these areas. Methods: In total, 1,097 students between grades 3 and 6 at 19 elementary schools were recruited from four areas with high mercury exposure as identified by the KNEHS. Total mercury levels in biological samples were compared with health check-ups performed on the schoolchildren. Biological monitoring, supported by questionnaires, a computerized neurobehavioral test, a posturography test and a personality test, were applied. Results: Triglycerides showed a significant relation with mercury in blood, urine and hair. Total mercury concentrations were divided into two groups: upper and lower concentration groups based on the median value. In the computerized neurobehavioral test, the upper blood mercury group showed a greater reaction time for color-word vigilance (p<0.05). In the posturography test, the intensity value of the tremor test showd high significant relations with mercury levels (p<0.01). In the personality test, self-consciousness, misdeeds and family relationships showed significant differences between the upper and lower urine mercury groups (p<0.01), and specific reactions, ego resilience and hyperactivity also showed some differences (p<0.1). Conclusion: Some items in the neurobehavioral test, posturography test and personality test showed significant relations with biological mercury levels. Therefore, monitoring and appropriate management of students showing high mercury levels are recommended in order to reduce their mercury exposure.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1470-1474
• /
• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• Bulletin of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.805-810
• /
• 2007

Molecular recognition for a specific cation depending on the change of the oxidation state of the metal catalyst component contained in the hydrogel network has been studied in a self-oscillating hydrogel. The selfoscillating hydrogels are synthesized by the copolymerization of N-isopropylacrylamide (NIPAAm), lead methacrylic acid (Pb(MAA)2), and Ru(bpy)3 2+ monomer as a metal catalyst component. The recognition for a specific cation (in this study, Ca2+ has been used) is characterized by the adsorbed amount of Ca2+ into the gel. The recognition of the gels for Ca2+ is higher at the temperature below the LCST, and also higher at the oxidized state than at reduced state of the metal catalyst component which corresponds to a more swollen state. Moreover, a propagating wave induced by a periodic change of the oxidation state with the diffusion phenomena in the oscillating hydrogel shows a possibility for temporal and site-specific molecular recognition due to the local swelling of the gel.