• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.52-60
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• 1985

Oxides of nitrogen (NO$_x$) in exhaust gases was determined by absorbing the gas in alkaline peroxide solution containing 0.03${\%}$ H2O2 and 0.1N NaOH. About 100 ppm of NO$_x$ was rapidly oxidized to NO$_2$ or N$_2$O$_5$ by H$_2$O$_2$ and required a contact time of 2 minutes with the absorbing solution for complete absorption. With vigorous shaking including air or oxygen gas, high concentration of NO$_x$ (>200 ppm) can be absorbed within 30 minutes. The remaining H$_2$O$_2$ affect the absorbance of color solution strongly. However, the excess H$_2$O$_2$ was completely decomposed by zinc powder 0.5g and the sample solution should be adjusted to the pH range 6.1∼6.6 before the reduction so that conversion of nitrate to nitrite ion is possible. The absorbed NO$_x$ is determined colorimetrically by the diazotization-coupling method with sulfonilamide and NEDA as the coupling agent. The sensitivity of the new method was 4.48 ${\times}$ 10$^4$ as molar absorptivity which was high sensitive compared with that obtained for the usual zinc reduction NEDA method with O$_3$. This method was far more rapid, brief and accurate than previously published O$_3$-NEDA method in Korean industrial standard.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.61-71
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• 2007

The photosynthetic characteristics and primary production by phytoplankton in open waters of two wetlands (the Banwol and the Donghwa wetland) of Sihwa Constructed Wetland with different water chemistry were investigated to provide the information for the wetland management considering the water treatment efficiency. During the study period (from March to October, 2005) the primary productivity in open waters ranged from 481 to 11,275 mgC $m^{-2}$ $day^{-1}$, which is very high compared with the eutrophic level of 600mgC $m^{-2}$ $day^{-1}$. From the analysis of the photosynthesis-irradiance (P-I) model parameters, the photosynthetic characteristics may be affected by different concentration and ratio of nutrient (N and P) between two wetlands. Assimilation number (AN) was higher in the Donghwa wetland (average AN: 8.5gC $gChl^{-1}$ $hr^{-1}$) with high P and low N/P ratio than the Banwol wetland (average AN: 5.8gC $gChl^{-1}$ $hr^{-1}$) with high N and high N/P ratio. This result indicates that AN may be concerned with phosphorus than nitrogen and low NIP ratio. Positive correlation (R=0.81) was observed between the initial slope and AN, implying that AN was high in case of phytoplankton having more active photosynthesis ability under low light. On the other hand, maximum photosynthesis (Pmax) was related positively with chlorophyll a concentration showing correlation coefficient of 0.47. In this study, considering the high primary production through phytoplankton photosynthesis in open waters of Sihwa Constructed Wetland, the produced organic matter by phytoplankton may affect the water quality within wetland and its efficiency of water treatment. Also, the photosynthetic characteristics may be affected by different nutrient enrichment (especially phosphorus) of wetlands. This study suggests that the production by phytoplankton and its characteristics in open water of constructed wetland for water treatment should be considered to improve the removal efficiency of organic matter.

• Journal of Korean Society on Water Environment
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• v.24 no.5
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• pp.563-568
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• 2008

In petroleum refining industry, caustic (NaOH) solution is used to remove $H_2S$ from hydrocarbon streams in naphtha cracking process. Once $H_2S$ is absorbed in caustic solution, the solution becomes known as spent sulfidic caustic (SSC), which contains high concentrations of hydrogen sulfide and alkalinity. This study was focused on the evaluation of autotrophic denitrification by SSC in a hybrid Bardenpho process. SSC was injected to the anoxic (1) and anoxic (2) tank at different S/N ratio. In a previous lab-scale study, as we operated a modified Ludzack-Ettinger process, it was observed that the COD increment of effluent and nitrification failure happened because of non-biodegradable matters in SSC and high pH, respectively. Thus cilia media was packed at 2.4%(v/v) in all aerobic tanks and the pH of SSC was neutralized from 13.3 to 11.5 with addition of sulphuric acid ($H_2SO_4$). Consequently, these strategies were successful because no COD increment of effluent was observed and nitrification failure did not happen. The maximum TN removal efficiency was 77.5% when SSC was injected to both the anoxic (1) and anoxic (2) tanks. The mean TN concentration of effluent in this condition was 5.8 mg/L.

• Molecules and Cells
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• v.38 no.5
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• pp.457-465
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• 2015

The 15-kDa selenoprotein (Sep15) is a selenoprotein residing in the lumen of the endoplasmic reticulum (ER) and implicated in quality control of protein folding. Herein, we established an inducible RNAi cell line that targets Sep15 mRNA in Chang liver cells. RNAi-induced Sep15 deficiency led to inhibition of cell proliferation, whereas cell growth was resumed after removal of the knockdown inducer. Sep15-deficient cells were arrested at the G1 phase by upregulating p21 and p27, and these cells were also characterized by ER stress. In addition, Sep15 deficiency led to the relocation of focal adhesions to the periphery of the cell basement and to the decrease of the migratory and invasive ability. All these changes were reversible depending on Sep15 status. Rescuing the knockdown state by expressing a silent mutant Sep15 mRNA that is resistant to siRNA also reversed the phenotypic changes. Our results suggest that SEP15 plays important roles in the regulation of the G1 phase during the cell cycle as well as in cell motility in Chang liver cells, and that this selenoprotein offers a novel functional link between the cell cycle and cell motility.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.254-260
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• 2024

This study is to manufacture a titanium dioxide (TiO₂) photocatalyst by recycling sludge generated using titanium tetrachloride (TiCl₄) as a coagulant. Compared to general sewage, a TiCl₄ coagulant was applied to dyeing wastewater containing a large amount of non-degradable organic compounds to evaluate its performance. Then the generated sludge was dried and fired to prepare a photocatalyst (TFS). Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and nitrogen oxide reduction experiments were conducted to analyze the surface properties and evaluate the photoactive ability of the prepared TFS. After using titanium tetrachloride (TiCl₄) as a coagulant in the dyeing wastewater, the water quality characteristics were measured at 84 mg/L of chemical oxygen demand (COD), 10 mg/L of T-N, and 0.9 mg/L of T-P to satisfy the discharge water quality standards. The surface properties of the TFS were investigated and the anatase crystal structure was observed. It was confirmed that the ratio of Ti and O, the main components of TiO₂, accounted for more than 90 %. As a result of the nitric oxide (NO) reduction experiment, 1.56 uMol of NO was reduced to confirm a removal rate of 20.60 %. This is judged to be a photocatalytic performance similar to that of the existing P-25. Therefore, by applying TiCl₄ to the dyeing wastewater, it is possible to solve the problems of the existing coagulant and to reduce the amount of carbon dioxide generated, using an eco-friendly sludge treatment method. In addition, it is believed that environmental and economic advantages can be obtained by manufacturing TiO₂ at an eco-friendly and lower cost than before.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.2
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• pp.180-186
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• 2009

In this study, Crotalaria sessiliflora L., leaf was extracted with a solvent mixture of $CH_2Cl_2$ and $CH_2OH$ (3:1). In order to draw or separate effective components from the leaf extract with high activity, a 1:1 solvent mixture of water and butanol was used after removal of the sugar and fat from the extract. From the decompressed and concentrated butanol layer, 10 small fractions (Fr1, Fr2, Fr3, Fr4, Fr5, Fr6, Fr7, Fr8, Fr9, and Fr10) were obtained using a chromatography column filled with sephadex LH-20. The activity of each fraction was measured by the same method as that used to measure the antioxidant effect of each part(p<0.05). The Fr1, Fr4, and Fr6 fractions showed the highest activity levels(p<0.05). The vital unknown material that vitality exists in the strong butanol fractions of F1, F4 and F6 will be isolated and identified. Currently, we are performing for a single compound from an unknown peak by instrumental analysis.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.1
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• pp.69-81
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• 2005

The objective of this study was to evaluate the toothbrush abrasion characteristics of class V restorations. Thirty extracted human premolars, which were collected from oral surgery clinics were used. We mounted five teeth in a metal ring mold of 50 mm in diameter and 15 mm in height using chemically cured acrylic resin. Class V cavities were prepared in lingual cervical root surfaces and restored using one of following restorative materials : Dentin Conditioner/Fuji II LC (Group FL), All Bond II/Z-250 (Group ZT), One-up Bond F/Palfigue Estelite (Group PE), F2000 Primer/Adhesive (Group FT), and Prime & Bond 2.1/Dyract AP (Group DR). They were stored under distilled water at $37^{\circ}C$ for seven days. The toothbrush abrasion test was conducted using a wear testing machine of pin-on disk type under a load of 1.5 N for 100,000 cycles. We have examined the bonded interfaces, the changes of surface roughness and color of abraded surfaces. From this experiment, the following results were obtained. 1. The change of surface roughness showed high degree: RMGIC>compomer>composite resin (p<0.05). 2. Because of the protrusion and missing of filler particles, SEM observation of abraded surfaces of RMGIC and compomers revealed the increase of surface roughness due to the selective removal of matrix resin. 3. The color change by toothbrush abrasion was affected in large part by the change of $L^*$ and $b^*$ of resin composites (p<0.05). 4. The color change by toothbrush abrasion was so small to detect by human eyes. 5. SEM observation of abraded surfaces revealed the interface bonding was the best in the FT group.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.1
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• pp.21-28
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• 2010

Phenolic compounds affect intracellular free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) signaling. The study examined whether the simple phenolic compound octyl gallate affects ATP-induced $Ca^{2+}$ signaling in PC12 cells using fura-2-based digital $Ca^{2+}$ imaging and whole-cell patch clamping. Treatment with ATP ($100\;{\mu}M$) for 90 s induced increases in $[Ca^{2+}]_i$ in PC12 cells. Pretreatment with octyl gallate (100 nM to $20\;{\mu}M$) for 10 min inhibited the ATP-induced $[Ca^{2+}]_i$ response in a concentration-dependent manner ($IC_{50}=2.84\;{\mu}M$). Treatment with octyl gallate ($3\;{\mu}M$) for 10 min significantly inhibited the ATP-induced response following the removal of extracellular $Ca^{2+}$ with nominally $Ca^{2+}$-free HEPES HBSS or depletion of intracellular $Ca^{2+}$ stores with thapsigargin ($1\;{\mu}M$). Treatment for 10 min with the L-type $Ca^{2+}$ channel antagonist nimodipine ($1\;{\mu}M$) significantly inhibited the ATP-induced $[Ca^{2+}]_i$ increase, and treatment with octyl gallate further inhibited the ATP-induced response. Treatment with octyl gallate significantly inhibited the $[Ca^{2+}]_i$ increase induced by 50 mM KCI. Pretreatment with protein kinase C inhibitors staurosporin (100 nM) and GF109203X (300 nM), or the tyrosine kinase inhibitor genistein ($50\;{\mu}M$) did not significantly affect the inhibitory effects of octyl gallate on the ATP-induced response. Treatment with octyl gallate markedly inhibited the ATP-induced currents. Therefore, we conclude that octyl gallate inhibits ATP-induced $[Ca^{2+}]_i$ increase in PC12 cells by inhibiting both non-selective P2X receptor-mediated influx of $Ca^{2+}$ from extracellular space and P2Y receptor-induced release of $Ca^{2+}$ from intracellular stores in protein kinase-independent manner. In addition, octyl gallate inhibits the ATP-induced $Ca^{2+}$ responses by inhibiting the secondary activation of voltage-gated $Ca^{2+}$ channels.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.123-130
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• 2020

Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 μS/cm and temperature, 19.4-22.2 ℃) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.293-298
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• 2005

Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. The performance load of SBR process was shown to be 0.095kg ${\cdot}$ TOC/$m^{3}$ ${\cdot}$ day. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sluge produced in the SBR process is characterized by low generation rate (about 0.36kg ${\cdot}$ MLSS/kg ${\cdot}$ TOC) and excellent settleability. The number of Bacillus sp. in the SBR was 24.2%, indicating that Bacillus sp. was a predominant species in the reactor.