• Analytical Science and Technology
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• v.23 no.3
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• pp.225-232
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• 2010

In present study, a conventional sol-gel method was used to prepare Fe-ACF/$TiO_2$ composites, a kind of composite photocatalysts, whose capability was evaluated by degrading methylene blue (MB) solution. The particle size, surface structure, crystal phase and elemental identification of the composites prepared were characterized by BET, SEM, XRD and EDX, respectively. The spectra of MB concentration degraded under visible light were obtained by UV/Vis spectrophotometer. These obtained spectra demonstrated the photocaltalytic activity from removal concentrations of MB. It was considered that these photonic activities are induced by a strong synergetic reaction among ACF, $TiO_2$ and Fe in the composite photocatalysts under visible light.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.375-380
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• 2011

This study investigated the effects of inorganic sulfur on metastasis in MDA-MB-231 human breast cancer cells. MDA-MB-231 cells were cultured in the absence or presence of various concentrations (12.5, 25, or 50 ${\mu}mol$/L) of inorganic sulfur. Cell motility, invasion, and the activity and mRNA expression of matrix metalloproteases (MMPs) were examined. Numbers of viable MDA-MB-231 cells did not differ by inorganic sulfur treatment from 0 to 50 ${\mu}mol$/L within 48 h. Inorganic sulfur significantly decreased cell motility and invasion in the MDA-MB-231 cells in a dose-dependent manner (P<0.05), as determined using a Boyden chamber assay and a Matrigel chamber. The activities of MMP-2 and MMP-9 were significantly reduced by inorganic sulfur in a dose-dependent manner (P<0.05). The inorganic sulfur also significantly inhibited MMP-2 and MMP-9 expression in the cells (P<0.05). These data suggest that inorganic sulfur can suppress cancer cell motility and invasion by inhibiting MMP-2 and MMP-9 activity and gene expression in MDA-MB-231 cells.

• Journal of the Korean Chemical Society
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• v.28 no.6
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• pp.355-360
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• 1984

A new absorption spectrum observed from dilute aqueous solutions of methylene blue$(MB^+)$ and tetraphenylborate(TPB$^-$) ions was investigated by spectrophotometry. The species responsible for the spectrum can be a charge-transfer complex formed between the two, univalent, and poorly hydrated ions in order to minimize the disturbance to the water structure. However, as the absorption band of MB$^+$ is split into two bands with exciton splitting of about 2,000 cm$^{-1}$, the formation of double ion-pair, (MB-TPB)$_2$ appears to be more favorable than the charge transfer complex.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.927-932
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• 2009

Toxic and recalcitrant organic pollutants in wastewaters can be effectively treated when advanced oxidation and biodegradation are combined, ideally with intimate coupling, in which both processes occur simultaneously in the same system. One means to achieve intimate coupling is to coat nanoscale $TiO_2$ on the outside of macroporous biofilm carriers. This study investigated the kinetics of photocatalysis with $TiO_2$-coated porous carriers. The carriers were made of polyvinyl alcohol (PVA) and coated with $TiO_2$ using a low-temperature sol-gel process. The $TiO_2$-coated carriers catalyzed the oxidation of methylene blue (MB) effectively under irradiation of UV light. The overall reaction rate with adsorption and photolysis saturated at high MB concentration, and approached the adsorption rate, which was first order for all MB concent rations. This result indicates that adsorbed MB may have slowed photocatalysis by blocking active sites for photocatalysis. The overall kinetics could be described by a quasi-Langmuir model. The estimated maximum specific (per unit mass of $TiO_2$) transformation rate of MB by the $TiO_2$-coated carriers was four times larger than that obtained from slurry-$TiO_2$ reactors. This observation demonstrated that the $TiO_2$ present as a coating on the carriers maintained high efficiency for transforming recalcitrant organic matter via photocatalysis. These findings serve as a foundation for advancement of an intimate coupling of photocatalysis to biodegradation.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.412-420
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• 2023

In this study, red mud/fly ash based geopolymer adsorbents (RFGPA) were prepared with calcination temperatures of 200, 400, and 600 ℃, and the effects of these calcination temperatures on the adsorption of methylene blue (MB) were investigated. In addition, the prepared RFGPA was characterized using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, and Brunauer-EmmettTeller (BET) analysis. The results of the adsorption kinetics of MB at RFGPA prepared calcination temperatures indicated that the adsorption equilibrium of MB was reached after about 72 h. From the results of the adsorption isotherm, we verified that the degree of adsorption increased with increasing MB concentrations. In addition, the adsorption amount (Q) of MB decreased with an increase in calcination temperature. The experimental adsorption isotherm data were well fitted to the Freundlich and Sips equations compared to the Langmuir equation. In order to verify the effects of photocatalytic decomposition (C/C₀) of MB on Fe₂O₃ present in prepared RFGPA, the degree of decomposition of MB was examined under dark and visible conditions. Results indicated that the decomposition of MB in visible conditions was about 3.0 times faster than that in dark conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.983-988
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• 2007

Epigallocatechin gallate (EGCG), a principal antioxidant derived from green tea, is one of the most extensively investigated chemopreventive phytochemicals. However, the effect of EGCG on proliferation in MDA-MB-231 breast cancer cell is not well known. We investigated the effect of EGCG on protein and mRNA expression related to cell proliferation in MDA-MB-231 human breast cancer cell lines. We cultured MDA-MB-231 cells in the presence of 0, 5, 10 and 20 ${\mu}m$ of EGCG. EGCG significantly inhibited the cancer cell proliferation (p<0.05). In MDA-MB-231 huamn breast cancer cell, EGCG lowered $ErbB_2$ and $ErbB_3$ protein as well as mRNA expression. In addition, protein and mRNA expression of phosphorylated Akt and total Akt were significantly decreased (p<0.05). We suggest that EGCG inhibits cell proliferation through $ErbB_2$, $ErbB_3$ and Akt cell signaling.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.27-35
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• 2002

Background: A perioperative myocardial infarction(PMI) is one of the major complications after CABG. Among diagnostic methods of PMI, CK-MB activity assays have been increasingly replaced by CK-MB mass assays, which have more sensitive, simple measurement. Also, new cardiac-specific and -sensitive marker, cardiac troponin I(cTnl), has been shown to be a marker of myocardial infarction. We report our evaluation of clinical significance of CK-MB mass and cTnl as a marker of PMI after CABG. Material and Method: We studied 32 patients who underwent CABG at Kangdong Sacred Hospital between April 2000 and April 2001. Postoperative serum CK-MB activity level, serum CK-MB mass, cTnl, electrocardiogram, echocardiogram, and clinical data were recorded prospectively The diagnosis of PMI was defined as positive 2 among 3 or all of the following , by a new Q wave on the electrocardiogram, by serum CK-MB activity higher than 200 lU/L within 72 hours after operation, and by new regional wall motion abnormality on the echocardiogram. Result: After CABG, 3 patients had sustained a PMI according to current diagnostic criteria. As serum CK-MB activity time course, a level of CK-MB activity 12 hours after CABG had very linear correlated significance with serum CK-MB mass 24hours(R=0.946) and cTnl 48 hours(R=0.933) after CABG(p=0.000). As we used a receiver operating characteristics curve(ROC curve) for a diagnostic cutoff value in patients with PMI, serum CK-MB mass levels higher than 30.05 ug/L 24 hours after CABG detected the presence of PMI with an area under the ROC curve of 1.0, a sensitivity of 100%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 100%. Also serum cTnl levels higher than 17.15 ug/L 48 hours after CABG detected the presence of PMI with an area under the ROC curve of 0.98, a sensitivity of 100%, a specificity of 96.6%, a positive preclictive value of 75%, and a negative predictive value of 100% Conclusion: We concluded that both the measurement of CK-MB mass and cTnl are the easier, accurate methods as a diagnostic marker of PMT after CABG, also as a proposal of diagnostic cutoff value enables to an early detection of PMI. However, a 1arger number of patient will be needed because of statistic limitation that a small number of participating patients, a small number of PMI.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.963-971
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• 1992

A (4,6) block binary line code is proposed. In addition to being de-free and runlength-limited, the new code called MB46 is strictly bandwidth-limited to the Nyquist frequency, thus achieving improved bandwidth efficiency over previously known binary line code. A technique specially employed in the design of the code is described in depth, and some performance measures including the eye pattern and the power spectrum are presented as obtained by simulation.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.397-409
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• 2014

Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.268-279
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• 1997

In this paper, we show the movable boundary (MB) method is the effective bandwidth allocation strategy for the ABR service among existing bandwidth allocation methods. The MB method can gurantee the QOS requirement according to the service priority and improve bandwidth utilization using the characteristics of the ABR service. The threshold values of the MB, which have an important effect upon connection blocking probability(CBP) performance of each service, are obtained by simulation. The MB method with the fixed thresholds, however, may not have good performance to variation of input traffic parameters. We suggest the dynamic MB method which changes the threshold values adaptively according to the required bandwidth of input traffic. We also show that the dynamic MB method can urantee the CBP performance according to the service priority regardless of variation of input traffic parameters.