• Nuclear Engineering and Technology
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• v.28 no.1
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• pp.79-92
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• 1996

In a repository containing low-level waste, gas generation will occur principally by the coupled processes of metal corrosion and microbial degradation of cellulosic waste. This paper describes a mathematical model designed to address gas generation by these mechanisms and assesses the potential effects of gas generation on the performance of a radioactive waste repository. The metal corrosion model incorporates a three-stage process encompassing aerobic and anaerobic corrosion regimes ; the microbial degradation model simulates the activities of eight different microbial populations, which are maintained as functions both of pH and of the concentrations of particular chemical species. A prediction is made for gas concentrations and generation rates over an assessment period of ten thousand years in a radioactive waste repository. The results suggest that H$_2$will be the principal gas generated within the radioactive waste cavern.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.687-694
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• 2012

$Jeot-gal$ is a traditional Korean fermented seafood with a salt concentration of 15~20%. However, today's consumers prefer low-salted foods as they have become aware that high levels of salt cause hypertension and diabetes. In this study, the quality characteristics and shelf-life of low-salted squid $Jeot-gal$ were investigated at different fermentation temperatures and salt concentrations. The shelf-lives of 3%-salted squid $Jeot-gal$ fermented at -1, 4, and $10^{\circ}C$ were 45, 31, and 23 days, respectively, whereas those of 5%-salted squid $Jeot-gal$ were 52, 36, and 25 days. The DPPH radical scavenging activity of the ethanol extract of squid $Jeot-gal$ was stronger than that of the water extract. However, the other antioxidative activities, such as hydrogen peroxide and hydrogen peroxide radical scavenging activities, as well as enzyme inhibitory activities were very low at 20 mg/mL of water and ethanol extracts. Based on the results of the sensory evaluation, the quality of low-salted fermented squid $Jeot-gal$ was almost similar to that of commercial squid $Jeot-gal$ with a high salt concentration.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.86-93
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• 1997

Purpose: To assess the ability of in vivo H-1 MRS to determine the degree of malignancy and to characterize the histopathologic type of intracranial solid tumors. Materials and Methods: In vivo H-1 MR spectra of the pathologically-proven 81 intracranial soild tumors (low-grade glioma 17 cases, high-grade glioma 31 cases, lymphoma 9 cases, meningioma 8 cases, central neurocytoma 4 cases, medulloblastoma 3 cases, PNET 3 cases, metastasis 2 cases, others 4 cases) were analyzed. H-1 MR spectroscopy was performed on a 1.5T MR unit using PRESS sequence with a TR of 2000ms, a TE of 270 or 135ms and a voxel size of $2{\times}2{\times}2cm^3$ for all spectra. N-acetyl aspartate (NAA)/Creatine complex(Cr), Choline complex (Cho)/Cr, and lactate (Lac)/Cr ratios were measured on the peak heights of each resonance and compared among the different tumors. Results: All intracranial solid tumors demonstrated decreased NAA, elevated Cho and lactate, and variable Cr levels. All tumors showed increased Cho/Cr and Lac/Cr, whereas NAA/Cr level was decreased. Mean Cho/Cr and Lac/Cr ratios were significantly higher in high-grade gliomas than in low-grade gliomas. However, NAA/Cr ratio showed no significant difference between low-grade and high-grade gliomas. Very high Cho peaks were seen in lymphomas, meningiomas, medulloblastomas, and neurocytomas in addition to high-grade gliomas. Conclusion: H-1 MRS may be useful in differentiating between low-grade and high-grade gliomas, however cannot characterize the histologic types or subtypes of tumors.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.27-32
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• 2010

We used phototrophic bacteria to remove low concentrated organic materials (CODCr), nitrogen and phosphorus. We applied $COD_{Cr}$ 37.3 mg/L, $NH_3-N$ 4.0 mg/L, and $PO_4^{3-}-P$ 1.0 mg/L (C:N:P=100:10:1) in the batch test, and the removal efficiencies were shown as follow: $COD_{Cr}$ 87.4%, $NH_3-N$ 46.3%, $PO_4^{3-}-P$ 79.7%. The aerobic process with mixed phototrophic bacteria, ceramic media, and media KSP01 showed the removal efficiencies of $COD_{Cr}$, $NH_3-N$, and $PO_4^{3-}-P$, each as 72.7% and 79.2%, respectively in the lab-scale reactor. The maximum $PO_4^{3-}-P$ removal efficiency reached 92.6% by adjusting pH. There were three conditions used to remove $NH_3-N$. The highest removal efficiency was 98.5% with 10.2 L/min of aeration in 1-2 reactors, and the result of applying river-water showed the high removal efficiency of $NH_3-N$ (82.8%). Therefore, this purification system may be useful to control nitrogen and phosphorus at low concentration in field.

• Tuberculosis and Respiratory Diseases
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• v.63 no.3
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• pp.242-250
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• 2007

Background: Abnormal angiogenesis can induce hypoxia within a highly proliferating tumor mass, and these hypoxic conditions can in turn create clinical problems, such as resistance to chemotherapy. However, the mechanism by which hypoxia induces these changes has not yet been determined. Therefore, this study was conducted to determine how hypoxia induces changes in cell viability and extracellular microenvironments in an in vitro culture system using non-small cell lung cancer cells. Methods: The non-small cell lung cancer cell line, A549 was cultured in DMEM or RPMI-1640 media that contained fetal bovine serum. A decrease in the oxygen tension of the media that contained the culture was then induced in a hypoxia microchamber using a $CO_2-N_2$ gas mixture. A gas analysis and an MTT assay were then conducted. Results: (1) The decrease in oxygen tension was checked the anaerobic gas mixture for 30 min and then reoxygenation was induced by adding a 5% $CO_2-room$ air gas mixture to the chamber. (2) Purging with the anaerobic gas mixture was found to decrease the further oxygen tension of cell culture media. (3) The low oxygen tension resulted in a low pH, lactic acidosis and a decreased glucose concentration in the media. (4) The decrease in glucose concentration that was observed as a result of hypoxia was markedly different when different types of media were evaluated. (5) The decrease in oxygen tension inhibited proliferation of A549 cells. Conclusion: These data suggests that tumor hypoxia is associated with acidosis and hypoglycemia, which have been implicated in the development of resistance to chemotherapy and radiotherapy.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.174-178
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• 1999

An anthocyanin-deficient tomato (Lycopersicon esculentum Mill.) strain, H957, shows an unusual tolerance to low phosphorus (P). To investigate whether the tolerance originates from a tissue/cellular strength, plant tissue culture procedure was employed which facilitate to characterize the tolerance independent of morphological features. The tolerance was analyzed by comparing H957 against H883, its maternal wild type, while each explant was co-cultured on minimal P media. Comparisons were made in fresh weight, dry weight, callus and shoot formation, mineral contents, and P utilization ratios at $0-400{\cdot}\bar{I}MP$, . Growth of the two strains was severely impaired at 0 and $12.5{\cdot}\bar{I}MP.\;At\;25-200{\cdot}\bar{I}MP$, however, H957 consistently showed a greater fresh and dry weight than H883. Shoot onset of H957 was less delayed than H883 compared to optimal P conditions. H957 tissue contains an overall lower P concentration than H883. These observations indicate that H957 may tolerate to low P by its tissue or cellular strength in P utilization side from its morphology.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.1-8
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• 2005

Fractional compositions and leaching potentials of Cd, Cu and Zn were investigated in the soils which had been disposed with the metal processing wastes, tungsten mine tailings and low quality coal mine area. Total concentrations of metals in these soils were higher than in non-polluted paddy and upland soils. Fractions of Cd, Cu and Zn were mostly reducible, organic and residual forms, but varied with origins of wastes. Residual fraction was a predominant form in the nonpolluted soils. Leaching potentials of metals were higher in polluted soils than in non-polluted soils. Metals leached were higher at pH 4.0 than 7.0 and increased with the duration time. After 25 to 35 hrs, metals released from soils reached a pseudoequilibrium. Leaching potential of metals in non-polluted soils was low due to high percentage of residual fractions.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.286-291
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• 2016

This study was carried out to evaluate the feasibility of air-stripping by DIWS(Dip Injection Wet Scrubber) system on high concentration of ammonia wastewater more than 10,000 mg/L. In the case of changing temperature from $30^{\circ}C$ to $70^{\circ}C$ maintaining pH 12.5 within the 72 hours, the removal efficiency of T-N by the present treatment plant was increased to 90.5% which was initially kept 70.3%. Although the high concentration of T-N with 9,120~12,955 mg/L was treated by micro-bubble through DIWS system maintaining the temperature of $30^{\circ}C$ within the 20 hours, the removal efficiency of T-N reached 91.9%, which indicated the possibility of air-stripping.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.84-91
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• 1998

Random copolymers of N-isopropyl acrylamide (NIPAAm) and acrylic acid (AAc) which exhibit temperature- and pH-responsive behavior were synthesized by free-radical polymerization. The copolymers were characterized by means of FT-IR spectrometry and titration. The influence of polyelectrolyte on the lower critical solution temperature (LCST) of pH/temperature-sensitive polymers was investigated in the pH range of 2-12. The LCSTs of PNIPAAm/water in poly(NIPAAm-co-AAc) were determined by cloud-point measurements. A polyelectrolyte complex was prepared by mixing poly(NIPAAm-co-AAc) with poly(allylamine) (PAA) or poly(L-lysine) (PLL) solutions as anionic and cationic polyelectrolytes, respectively. Back titration was performed to determine the content of AAc and to study the effect of comonomer ionization on the LCST. The LCSTs of PNIPAAm/water in the copolymers were strongly affected by pH, presence of polyelectrolyte, AAc content, and charge density on the polymer. The polyelectrolyte complexes were formed at neutral condition. The influence of more hydrophobic PLL as polyelectrolyte on the cloud-point of PNIPAAm/water in the copolymer was stronger than that of poly(allylamine) (PAA).

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.135-143
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• 1988

The treatments of $H_2O_2$ were more effective on the degradation of difficult digestible materials by increasing the treatment concentration and adjusting the pH to alkaline. The smaller particle size of rice straw was, the more these effect. $2N_2CO_3{\cdot}3H_2O_2$, didn't need to adjust on pH, but the effect of treatment was lower than $H_2O_2$(pH 11.5) treatment. Lignin and hemicellulose content were decreased by the alkaline peroxide treatments. The fermentation of rice straw which pretreated with alkaline peroxide, the content of total nitrogen and ash increased. And NDF, hemicellulose and lignin were decreased, and ADF and cellulose decreased as the lower concentra­tion of treatment. The digestibility of rice straw which treated alkaline peroxide was increased with increasing the treatment concentration. The treatment of 12% $H_2O_2$(pH 11.5) and 12% $2Na_2^-CO_3{\cdot}3H_2O_2$ increased the digestibility from 31.1% to 89.4% and 76.8% compared with nontreated rice straw, respectively. The digestibility of fermented rice straw which pretreated with alkaline peroxide was effectively increased as the pretreatment concentration was low. Semi-dry treat­ment of $H_2O_2$ decreased the ADF and cellulose, and exhibited the 57.5% of digestjbility. Fer­mentation of rice straw which semi-dry treated with 4% $H_2O_2$, increased the digestibility from 33.4% to 63.4% compared with control.