• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.335-340
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• 2005

The forward dissolution rate of a borosilicate waste glass was determined as an interlaboratory study(ILS) testing program for the evaluation of precision in the measurement of the dissolution rate or a waste glass using a single-pass flow-through(SPFT) test, whose conducting practice has been written for standardization through American Society for Testing and Materials (ASTM). A simulated low-activity waste glass powder with a size of 100/200 mesh was dissolved by lithium buffer solution (pH=10) at 70? under Ar atmosphere. By plotting the dissolution rates as a function of silicon and boron concentration in eluate, the forward dissolution rate of the glass was obtained as about $2.7\times10^{-5}g{\cdot}m{\cdot}s^{-1}$ in our laboratory.

• 한국해양학회지
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• v.8 no.1
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• pp.9-21
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• 1973

When industrial wastewater containing fluoride runs into the ocean, approximately 0.1ppm of F$\^$-/ will react with seawater and will be eventually lost, and the remaining F$\^$-/ can be determined withe the ALC. Therefore F$\^$-/ is eligible to be used as a tracer of pollutant which contains fluoride. Determination of F$\^$-/ in the seawater with the Dotite reagent, Alfusone, has been made by the following method: To 10 ml of water sample, 1 ml of buffer solution (pH=4.0), 8 ml of acetone, and 1ml of 10% Alfusone were added and diluted to 25ml with distilled water. After 20 minutes the absorbance at 620 nm against a reagent blank was measured. The distributions of F$\^$-/ in Jinhae Bay has been made on the basis of water samples collected from 103 different sampling stations occupied in Jinhae Bay. The water samplings, three in the spring tide and two in the neap tide, were taken from surface layer during the flood and ebb tide periods respectively. The average concentration of F$\^$-/ in the bay, except the area to which the wastewater runs off from the Chemical plant, was 1.45 ppm(1.07-6.33ppm), and that of F$\^$-/ in the plant effluent was 330ppm, occasionally up to 562 ppm. Thus high levels of F$\^$-/ in the bay are strongly correlated to the amount of effluent from the plant, and waters of Jinhae Bay contains at least 0.13% of the plant effluent.

• Journal of Microbiology
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• v.34 no.2
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• pp.192-197
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• 1996

L-Xylosone was detected as its quinoxaline derivative in the degradation solution of dehydro-L-ascorbic acid. The production rate of L-xylosone was much faster in aerated phosphate-cirate buffer (pH 5. 6) than in pure water. L-Xylosone and dehydro-L-ascorbic acid were identified in the crude extracts of Saccharomyces cerevisiae. The concentration of L-xylosone in the crude cell extracts was calculated to be about 0.2 nmol $(mg protein)^{-1}$. When L-xylosone was added to asynchronous culture of S. cerevisiae, it inhibited primarily the synthesis of protein and RNA. Examination of the effect of L- xylosone on synchronous culture of the yeast indicated that L-xylosone inhibited the initiation of DNA replication and that the cells were arrested at $G_1$, stage of cell division cycle. These results suggested a possibility that L-xylosone can act as an inhibitor of cell growth.

• Analytical Science and Technology
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• v.17 no.3
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• pp.217-224
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• 2004

A taste sensor system composed of mini electrode array was built in a flow cell. Potentiometric signals from 9 electrodes were collected for drinking waters and alcoholic beverages which were diluted in a low concentration buffer solution (0.005 M Tris-$H_2SO_4$ pH 7.2) for the measurement. The measured results were treated with the principal component analysis (PCA), and grouped on a two or three dimensional PCA coordinate to discriminate the tastes of each beverage. It is demonstrated that the taste sensor system of this work may be used for the quality control of beverages in production or the examination of their taste variation in the market.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.131-137
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• 1994

Drug delivery system by the use of red blood cells was established to sustain the release of drugs in the circulatory system by the intravenous injection. The entrapment method by the preswelling technique was re-examined and evaluated for searching the new entrapping conditions without hemolysis. The addition of 4 volume of $0.6{\times}\;hank's$ balanced salt solution (HBSS) into 1 volume of 50% red blood cells suspension did not induce the hemolysis and change the hematocrit level in this experimental condition (within 15 min). Most of daunorubicin could be entrapped into red blood cells within 15 min. While the intracellular adenosine triphosphate (ATP) level followed by the entrapment was reduced to 86% of normal ATP level, the membrane fluidity and the shape factor of red blood cells were not altered. The release rate of daunorubicin from red blood cells was affected by the hemolysis under this condition. To maintain the intracellular ATP in red blood cells, the new reaction buffer was made With the addition of ATP and sodium pyruvate during the entrapment procedure because the hemolysis during the release test would reflect the loss of intracellular ATP that might result in the decrease of the viability in vivo. The addition of ATP raised the intracellular ATP level, which protect the hemolysis during the release test.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.249-255
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• 2009

The main object of this study was to prepare of w/o emulsion including glyceryl monooleate(GMO) and to evaluate its stability by using the recently developed $Turbiscan^{(R)}LAB$. GMO is the polar oily surfactant with the low HLB value, and it forms the gel phase of cubic structures after dissolves in aqueous media. Phosphate buffer solution (PBS) of pH 7.4 was prepared as the water phase and Marcol 52(mineral oil) was used as the oil phase in this study. GMO was used as the surfactant of W/O emulsion. W/O emulsion using GMO alone as a surfactant was very unstable. But the emulsion using both GMO and poloxamer 407 was more stable. The stability of W/O emulsions was evaluated after centrifuging the emulsions. But it was difficult with naked eye because an opaque and concentrated system like W/O emulsion was very turbid. So $Turbiscan^{(R)}LAB$ was used to detect the destabilization phenomena in non-diluted emulsion. As a result, the W/O emulsion using the proper amounts of GMO and poloxamer 407 was more stable among them using GMO of various amounts. But it seems that the other element for the stability of W/O emulsion including GMO was required. Furthermore, the $Turbiscan^{(R)}LAB$ was a very efficient analyzer for evaluating the physical stability of emulsion.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.783-790
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• 2016

Objectives: The purpose of this study is to evaluate the non-enzymatic antioxidants stabilities in dentifrices by ascorbic acid and tocopherol according to the chemical condition. Methods: For the analysis of two antioxidants, HPLC UV detector system was used. HPLC was performed using sodium sulfate, acetonitrile(ACN), methanol(MeOH) and measuring absorbance at 240-295 nm. To confirm general pH reaction of two compounds, buffer solution was prepared for the analysis. The dentifrice was titrated by pH so as to examine the change of elapsed time in dentifrice. Linearity of calibration curve of two antioxidants was measured. Results: Each compound showed good linearity at optimized wavelength as well as showing good precision. General pH reaction of two antioxidants was examined. Ascorbic acid showed the highest residue(63.23%) at pH 10 and the lowest residue(2.77%) at pH 4. Tocopherol showed the highest residue(55.70%) at pH 7 and the lowest residue(3.31%) at pH 4. As a result of changing elapsed time of antioxidants in dentifrice by pH, components were remained stably at low temperature($39.2^{\circ}F$) and pH 7. Conclusions: It is necessary to keep dentifrice including ascorbic acid and tocopherol, and non-enzymatic antioxidants at pH 7 and low temperature for improving chemical stability.

• Analytical Science and Technology
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• v.5 no.2
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• pp.177-184
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• 1992

A preparation method and response characteristics of a glucose sensor which consisted of pH-ISFET and glucose oxidase-immobilized membrane were investigated. The pH-ISFET glucose sensor was fabricated by immbilizing bovine serum albumin and glucose oxidase with glutaraldehyde on gate of the pH-ISFET. Effects of pH and concentration of working buffer and enzyme load on the pontentiometric response of the pH-ISFET glucose sensor were examined. Response characteristics for the determination of glucose in synthetic physiological saline solution(pH 7.4) were as follows. That is the concentration range of linear response, slope of linear response(sensitivity), and response time were $1.0{\times}10^{-4}{\sim}6.0{\times}10^{-3}M $, 4.1 mV/decade, and 12~15 min., respectively.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.735-742
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• 1996

Polymeric matrices were prepared with dextran and silver sulfadiazine by adding glycerine as a plasticiser. Namely, the release rate of the drug from the polymeric matrix formulations in dissolved phases was determined in a phosphate buffer solution. The results were as follows : The drug release time was delayed as drug loading contents increased, whereas it decreased as the glycerine concentration increased. The drug release time was not changed with varying the molecular weight of the dextran. The apparent release rate constant (k) increased as the composition of silver sulfadiazine and glycerine was increased. But the apparent release rate constant (k) was not changed with increasing molecular weight of the dextran.

• Journal of Sensor Science and Technology
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• v.16 no.6
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• pp.441-448
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• 2007

In this study, the fiber-optic fluoro-immunosensor was designed to detect foodborne pathogens. The fabricated system is composed of the multimode optical fiber on which antibodies are immobilized. Then, a sandwich immunoassay is applied to the fabricated the fiber-optic fluoro-immunosensor. In the "sandwich" binding format, a primary or "capture" antibody is immobilized on the core surface of the multimode optical fiber and a secondary or named as "tracer" antibody is added to the bulk solution. A tracer is labeled FITC (fluorescein isothiocyanate; ${\lambda}ex$=492 nm, ${\lambda}em$= 520 nm). Different concentrations of antigens are tested in different fibers. The detection limit of the fabricated system is 5.08×103 cfu/ml for Vibrio antigen and $0.1{\mu}g/ml$, $0.05{\mu}g/ml$ in non-labeled monolayer phosphate buffered saline (NMP), non-labeled monolayer carbonate bicarbonate buffer (NMC), respectively.