• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.745-751
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• 2013

Environmental Specimen Banks (ESBs) have been established widely in the world since 1979 for monitoring long-term bio-accumulation of environmental pollutants. The ESBs perform the retrospective analysis of representative biological samples collected regularly and store them in cryogenic condition. In Korea, National Environmental Specimen Bank (NESB) was established in 2009. Since then, NESB had prepared the standard operating procedures (SOPs) for the seven kinds of specimens (Red Pine (Pinus densiflora), Common Carp (Cyprinus carpio), and etc.) for monitoring the effect of environmental pollution on the terrestrial ecosystem and river ecosystem. In 2012, NESB added Black-tailed Gull (Larus crassirostris)'s eggs to the list of the environmental specimen for monitoring marine environmental pollution. In this study, we sampled the eggs of the Black-tailed Gull on two islands (Baekryeongdo of the West Sea and Hongdo of the South Sea). Especially, we selected eggs which remained in the early stages of embryo development for certifying the consistent and stable monitoring for environmental pollutants in egg contents. However, it was not considered to classify an order of eggs per clutch in this study. It is known that the concentration variations of pollutants exist among eggs in one clutch. Therefore, it is needed to consider the positions of eggs in the laying sequences to meet the objective of bioaccumulation monitoring. We collected 30 eggs in each site but the amount may be insufficient to achieve storage target (over 2,000 g). Therefore, we need to consider an optimal sampling size.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.23-27
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• 2006

Doxorubicin (DXR) is a type of anti-cancer drug called an 'anthracycline glycoside', It works by impairing DNA synthesis, a crucial feature of cell division, and thus is able to target rapidly dividing cells. Doxorubicin is a very serious anti-cancer medication with definite potential to do great harm as well as great good. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method was developed to identify and quantify DXR in small-volume biological samples. After the addition of internal standard (IS, $5{\mu}L\;of\;1{\mu}M/ml$ daunorubicin methanol solution) into the serum sample, the drug and IS were extracted by methanol. Following vortex for a 1min and centrifugation at 15,000g for 10 min the organic phase was transferred and evaporated under a vacuum. The residue was reconstituted with $350{\mu}L$ of mobile phase and $10{\mu}L$ was injected into C18 column with mobile phase composed of 0.05M ammonium acetate (0.1 M acetic acid adjusted to pH 3.5) and acetonitrile (40:60, v/v). The flow rate was kept constant at $350{\mu}L/min$. The ions were quantified in the multiple reaction mode (MRM), using positive ions, on a triple quadrupole mass spectrometer. The lower limits of quantification for Doxorubicin in plasma and small tissues were approximately 0.5 ng/mL and 0.5 ng/mL respectively. Intra- and inter-assay accuracy (% of nominal concentration) and precision (% CV) for all analytes were within 15%, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.122-126
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• 2012

The properties of Al-doped ZnO (AZO) films were investigated as a function of $H_2/(Ar+H_2)$ gas ratio using an AZO (2 wt% $Al_2O_3$) ceramic target in a radio frequency (RF) magnetron sputtering system. The deposition process was done at $200^{\circ}C$ and in $2{\times}10^{-2}$ Torr working pressure and with various ratios of $H_2/(Ar+H_2)$ gas. During the AZO film deposition process, partial $H_2$ gas affected the AZO film characteristics. The electron resistivity (${\sim}9.21{\times}10^{-4}\;{\Omega}cm$) was lowest and mobility (${\sim}17.8\;cm^2/Vs$) was highest in AZO films when the $H_2/(Ar+H_2)$ gas ratio was 2.5 %. When the $H_2/(Ar+H_2)$ gas ratio was increased above 2.5 %, the electron resistivity increased and mobility decreased with increasing $H_2/(Ar+H_2)$ gas ratio in AZO films. The carrier concentration increased with increasing $H_2/(Ar+H_2)$ gas ratio from 0 % to 7.5 %. This phenomenon was explained by reaction of hydrogen and oxygen and additional formation of oxygen vacancy. The average optical transmission in the visible light wavelength region over 90 % and an orientation of the deposition was [002] orientation for AZO films grown with all $H_2/(Ar+H_2)$ gas ratios.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.35-42
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• 2016

Formamide is a colorless fluid with ammonia odor, and irritable when inhaled. It has $LD_{50}$ value of > 5,577 mg/kg in rats for acute oral toxicity and NOAEL of 113 mg/kg/day for target organ (liver) of whole body toxicity. It is also known as reproductive toxicant (1B) and TWA(Time Weighted Average) for it is 10 ppm. Workplace measurements of work places dealing with formamide showed the ppm of all 25 samples was very lower than WEL. However, the exposure concentration can change, depending on workplace condition such as the intensity of work, operating local ventilation system, and wearing protection equipment (Respirators). Therefore, considering it with the risk of whole body toxicity and reproductive toxicity, exposure quantity of each imaginary scenario was calculated at 5.16, 1.72, and $0.43mg/m^3$. The average value was calculated at 0.02-0.58, 0.02-0.66 at 90 percent of cumulative distribution, 0.02-0.69 at 95 percent of cumulative distribution. Therefore, it was generally evaluated to be safe because all values were below 1. However, caution is required to prevent health hazard because it has hepatotoxicity and reproductive toxicity and risk of a high level momentary exposure, depending on the condition of workplace.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3123-3128
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• 2014

The liver is normally the major site of glucose metabolism in intact organisms and the most important target organ for the action of insulin. It has been widely accepted that insulin resistance (IR) is closely associated with postoperative recurrence of hepatocellular carcinoma (HCC). However, the relationship between IR and drug resistance in liver cancer cells is unclear. In the present study, IR was induced in HepG2 cells via incubation with a high concentration of insulin. Once the insulin-resistant cell line was established, the stability of HepG2/IR cells was further tested via incubation in insulin-free medium for another 72h. Afterwards, the biological effects of insulin resistance on adhesion, migration, invasion and sensitivity to cis-platinum (DDP) of cells were determined. The results indicated that glucose consumption was reduced in insulin-resistant cells. In addition, the expression of the insulin receptor and glucose transportor-2 was downregulated. Furthermore, HepG2/IR cells displayed markedly enhanced adhesion, migration, and invasion. Most importantly, these cells exhibited a lower sensitivity to DDP. By contrast, HepG2/IR cells exhibited decreased adhesion and invasion after treatment with the insulin sensitizer pioglitazone hydrochloride. The results suggest that IR is closely related to drug resistance as well as adhesion, migration, and invasion in HepG2 cells. These findings may help explain the clinical observation of limited efficacy for chemotherapy on a background of IR, which promotes the invasion and migration of cancer cells.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.455-464
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• 2015

Investments into existing cultural facilities are determined based on administrative district-based indices like population and area. Such macro judgment indices, however, fail to consider accessibility of cultural facilities from neighboring administrative districts and thus create problems including wasted budgets and duplicated investments. More recently, the government has made it a goal to increase the level of citizen awareness of these facilities, but achieving this requires the integration of neighboring administrative districts such that characteristics including transportation network and buildings are reflected in a comprehensive manner. This research therefore looks into Urban Network Analysis (UNA) as a means to investigate accessibility of cultural facilities. Use of UNA will make it possible to analyze the transportation network as well as building distribution, explained by building density, settled population, and other important building factors, in tandem, leading to the concentration of cultural facilities and the surrounding economic district being more properly reflected, and thus allowing for greater explanatory power in determining the level of accessibility. To test this, four target research districts were chosen from within the Gyeonggi Province and analyzed in terms of the accessibility of their everyday cultural facilities. Of the four districts of Gunpo, Anyang, Uiwang, and Gwacheon, accessibility of the first two districts, was found to be high, while accessibility was found to be relatively low for the latter two districts. This finding indicates that cultural facilities investments should be concentrated in the districts of Gunpo and Anyang.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.4
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• pp.391-404
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• 1991

Three anticncer agents which are different in time or dosage dependence as well as in phase specificity, namely mitomycin and adriamycin from natural products, and widely different cancer cell lines_Four epidermoid carcinomas originated from larynx, cervix, skin and gut were used toghether with one osteosarcoma as the target cell of single and combined administration of anticancer drugs. Semiautomated tetrazolium dye assay(MTT) appears to offer an attractive option for chemosensitivity of head and neck cancers since it is a simple, valid and inexpensive method of assessing chemosensitivity for large samples in a short time. The results obtained form this study were as follows. 1. Good correlations were obtained with the results of the MTT test and those of $^3H$ thymidine uptake assay. 2. $LD_{50}$ values of HIST and St.Ca. which showed relatively high doubling time on adriamycin were $30{\mu}g/ml$ and $15{\mu}g/ml$ while those of HeLa, Hep-2 and KHOS/NP were $2.1{\mu}g/ml$, $4.8{\mu}g/ml$, and $6.8{\mu}g/ml$ respectively. 3. The $LD_{50}$ value of 5-FU on five cancer cells were very high ranging from 15mg/ml to almost indefinite number, which means 5-FU is very resistant to epidermoid carcinomas or osteosarcoma examined in this study. 4. Mitomycin was relatively effective showing 80% cancer killing effect on HeLa, 70% on St. Ca. and 50% on Hep-2 at the high concentrations used. 5. Adriamycin was the most effective showing 90% cancer cell killing effect on KHOS/NP, 98% on HeLa, 80% both on Hep-2 and St. Ca. The least susceptible cancer cells toward adriamycin was HIST having only 55% cell killing effect at the high cincentration. 6. Combined therapy of adriamycin and 5-FU was more effective than single administration in all the cases examined. Most effective synergism was observed on St. Ca. at the low concentration, showing 21 times higher than each single administration.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.335-335
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• 2014

Over the past several years, transparent conducting oxides have been extensively studied in order to replace indium tin oxide (ITO). Here we report on fluorine doped zinc tin oxide (FZTO) films deposited on glass substrates by radio-frequency (RF) magnetron sputtering using a 30 wt% ZnO with 70 wt% SnO2 ceramic targets. The F-doping was carried out by introducing a mixed gas of pure Ar, CF4, and O2 forming gas into the sputtering chamber while sputtering ZTO target. Annealing temperature affects the structural, electrical and optical properties of FZTO thin films. All the as-deposited FZTO films grown at room temperature are found to be amorphous because of the immiscibility of SnO2 and ZnO. Even after the as-deposited FZTO films were annealed from $300{\sim}500^{\circ}C$, there were no significant changes. However, when the sample is annealed temperature up to $600^{\circ}C$, two distinct diffraction peaks appear in XRD spectra at $2{\Theta}=34.0^{\circ}$ and $52.02^{\circ}$, respectively, which correspond to the (101) and (211) planes of rutile phase SnO2. FZTO thin film annealed at $600^{\circ}C$ resulted in decrease of resistivity $5.47{\times}10^{-3}{\Omega}cm$, carrier concentration ~1019 cm-3, mobility~20 cm2 V-1s-1 and increase of optical band gap from 3.41 to 3.60 eV with increasing the annealing temperatures and well explained by Burstein-Moss effect. Change of work function with the annealing temperature was obtained by ultraviolet photoemission spectroscopy. The increase of annealing temperature leads to increase of work function from ${\phi}=3.80eV$ (as-deposited FZTO) to ${\phi}=4.10eV$ ($600^{\circ}C$ annealed FZTO) which are quite smaller than 4.62 eV for Al-ZnO and 4.74 eV for SnO2. Through X-ray photoelectron spectroscopy, incorporation of F atoms was found at around the binding energy of 684.28 eV in the as-deposited and annealed FZTO up to 400oC, but can't be observed in the annealed FZTO at 500oC. This result indicates that F atoms in FZTO films are loosely bound or probably located in the interstitial sites instead of substitutional sites and thus easily diffused into the vacuum from the films by thermal annealing. The optical transmittance of FZTO films was higher than 80% in all specimens and 2-3% higher than ZTO films. FZTO is a possible potential transparent conducting oxide (TCO) alternative for application in optoelectronics.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.177-183
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• 2016

Sewage treatment using microorganisms is affected by multiple factors such as microbial properties, characteristics of sewage and operating conditions, and nanoparticles inflow may cause negative effects on sewage treatment system especially on the system stability and efficiency. It was studied to assess the toxic effects of nanoparticles on microorganism growth. The activated sludge in the sewage treatment plant of university was cultured in the optimized medium for each strain. Bacillus (gram-positive), Pseudomonas and E.coli (gram-negative) in the activated sludge were selected as target microorganisms, and ZnO and $TiO_2$ were chosen as nanoparticles. For same concentration of nanoparticles, average growth inhibition rate of Bacillus was 60% or more, while that of Pseudomonas was less than 10%. The toxicity of nanoparticles was shown to be higher for gram-positive bacteria than gram-negative bacteria because of their differences on structure of cell wall, components of cell wall protein, physiology of cells and metabolism. ZnO affected 3 times more negative on the growth of microorganisms as compared to $TiO_2$. It was assumed that, therefore, toxicity of ZnO was found to be greater than $TiO_2$.