• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.280-287
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• 2015

Soil samples were collected from three depths (0-10 cm, 10-40 cm and 40-80 cm) of two forest sites including one plantation dominated by teak with some other minor species and another degraded natural forest in Cox's Bazar, Bangladesh to compare their soil properties. Some vegetation parameters were also studied. For this study $10{\times}10\;m$ and $2{\times}2\;m$ quadrats were used for the tree and undergrowth parameters, respectively. Soil samples were also collected from these quadrats. Between the two forest types, the highest levels of organic carbon, total nitrogen, available phosphorus, exchangeable bases and cation exchange capacity (CEC) were found in soils of the plantation. The soils were acidic in nature and exchangeable Al concentrations were low. Teak dominated forest plantation had higher soil fertility index (SFI) than the degraded natural forest site. Steps for reforestation and appropriate protection are needed to improve the situation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.161-161
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• 1998

To achieve the aim of this investigation, the extracellular protease was isolated from bacteria BAC-4, a strain was cultivated in the medium for the production of penicillin acilase in a period of 32 hours. The enzyme was first purified by aceton precipitation method, followed by ion exchange chromatography on DEAE-sephacel column. The highest specific activity of the aceton fraction was found to be 2.19 unit per mg, with degree of purification of 13 times. Further purification of the enzyme on DEAE -sephacel had a specific activity of 58.6 unit per mg and degree of purification of 344 times compared to its crude extract. The optimum pH of the enzyme was 8.4, and the potimum temparature was 37$^{\circ}C$. The K$\_$M/ and $V_{max}$ calculated at experiment conditions were found to be 0.66%(W/V) and 3.61 unit per mL respectively.

• YAKHAK HOEJI
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• v.28 no.3
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• pp.129-138
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• 1984

Specific [$^{3}H$] ouabain binding and $Ca^{2+}$ -uptake were measured to elucidate the role of high affinity [$^{3}H$] ouabain binding site in rat cardiac myocytes which contain 65% of rod cells. High affinity [$^{3}$H] ouabain binding site, which is about 3% of total pump sites, with apparent dissociation constant ($K_{D}$) of $1.1{\times}10^{-7}M$ and maximum binding site concentration (Bmax) of 1.2 pmol/mg protein ($1.754{\times}10^{5}cells$) were identified. At the concentration of $10^{-7}M$ to $10^{-4}M$, ouabain produced concentration dependent increase in $Ca^{2+}$-uptake of myocytes. The effect of ouabain on $Ca^{2+}$-uptake was not effected by membrane depolarization (elevated K+ in incubation medium) or verapamil. These results suggest that in rat ventricular myocytes the ouabain receptor complex to high affinity site may increase Na+ - $Ca^{2+}$ exchange across the sarcolemmal membrane by inhibition of Na+, K+ - ATPase.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.80-80
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• 2003

The isolation and purification of ferritin from the cricket, Gryllus bimaculatus haemolymph were accomplished by anion exchange column chromatography using HiTrap Q column (1.6 $\times$ 4 cm, Amersham Phamacia Co.), 7$0^{\circ}C$ heat and acid treatment, and gel filtration column chromatography using G4000SW column (0.75 $\times$ 60cm, TOSOH Co.) by FPLC system. (omitted)

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.692-696
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• 1993

Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.

• The Korean Journal of Zoology
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• v.30 no.2
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• pp.167-176
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• 1987

배추흰나비의 전용기 혈림프에서 $\beta$-N-Acetylglucosaminidase를 DEAE-cellulose ion exchange 및 Sephadex G-200 column chromatography 법을 이용하여 정제하였다. 정제된 효소는 7% acrylamide gel 전기영동에서 단일 band를 나타내었으며, 당을 함유한 복합단백질이었다. 최적 pH는 5.0, 최적반응온도는 6$0^{\circ}C$이었으며, 각 온도에서 10분간 incubation한 열안정성에 있어서는 6$0^{\circ}C$까지 비교적 높은 활성을 나타내었지만 7$0^{\circ}C$ 이후에는 거의 활성을 나타내지 않았다. 또한 Hg$^2$+ 처리는 심한 효소활성의 저해 현상을 보였지만, Mn$^2$+, $Mg^2$+ 등은 활성의 증가를 나타내었으며, Km 값은 6.67$\times$10-$^3$M, pl 값은 5.8, 분자량은 4.1$\times$105 daltons 이었다.

• Bulletin of the Korean Chemical Society
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• v.16 no.3
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• pp.205-210
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• 1995

Catalytic effects of various Schiff base metal(II) complexes on the reduction of thionyl chloride at glassy carbon electrode are evaluated by determining the kinetic parameters from cyclic voltammetry technique. The charge transfer process is affected strongly by the concentration of catalysts during the reduction of thionyl chloride. The catalytic effects are shown by both a shift of the reduction potential for thionyl chloride toward more positive direction and an increase in peak current. The diffusion coefficient value, Do, of the 8.17 ${\times}$ 10-9 $cm^2/s$ was observed at the bare glassy carbon electrode, whereas larger values (0.9-1.09 ${\times}$ 10-8 $cm^2/s$) were observed at the catalyst supported glassy carbon electrode. Significant improvements in the cell performance have been noted in terms of both exchange rate constants and current densities at glassy carbon electrode.

• Analytical Science and Technology
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• v.22 no.5
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• pp.355-359
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• 2009

An enzyme electrode bound by rubber solution was newly constructed and the test of its practicability were carried out. The binder of carbon powder was styrene-butadiene rubber dissolved in toluene and enzyme source was ground tissue of cabbage root. Volatilization of the solvent made the electrode material possess a mechanical robustness and a fast signal appearance. The electrode showed electrochemically irreversible characteristics and a powerful catalytic power (detection limit=$5.0{\times}10^{-5}M$, S/N=2). The double reciprocal plot of signal current and substrate concentration was ideally linear and the symmetry factor and exchange current density of the electrode used in this work were 0.35 and $4.93{\times}10^{-5}Acm^{-2}$ respectively.

• Journal of Radiation Protection and Research
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• v.22 no.4
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• pp.227-235
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• 1997

Cytogenetic studies were performed in peripheral blood lymphocytes from hospital workers occupationally exposed to low doses of radiation (0.30 - 40.07mSv). The workers were divided into three groups according to their job area : 18 diagnostic radiology, 17 therapeutic radiology, and 16 nuclear medicine. The control group consisted of 49 non-radiation workers with no history of exposure to radiation. A higher percentage of cells with aberration(1.275%) was observed in the workers compared to the controls(0.677%) and the difference was statistically significant(p<0.001). The frequency of chromosomal aberration was $0.706{\times}10^{-2}$/cell in the exposed and $0.344{\times}10^{-2}$/cell in the control(p<0.05). Chromosomal exchange frequency was $0.083{\times}10^{-2}$/cell in the control vs $0.245{\times}10^{-2}$/cell in the workers. There was no evidence of significant increase of chromosome aberration related to age or to the duration of employment. The frequency of chromosomal exchange in workers of nuclear medicine was $0.313{\times}10^{-2}$/cell, which was significantly higher than in the control($0.083{\times}10^{-2}$/cell) or other working groups: therapeutic radiology($0.265{\times}10^{-2}$/cell), and diagnostic radiology($0.167{\times}10^{-2}$/cell). No dose-effect relation was found between chromosome aberration and total cumulative doses, recent 5 yr, recent 2 yr cumulative dose. But in case of last 1 yr cumulative dose, dose-dependant increase was observed when controls were considered(p<0.05). The radiation dose which workers have received was much lower than the maximum permissible dose, but there was a significant difference in the frequency of chromosome aberration between occupationally exposed workers and control. So, it is clear that chromosome aberration is a quite sensitive indicator of radiation exposure and it can be detected at very low dose level of occupational exposure.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.177-180
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• 2003

A glassy carbon electrode(GCE) modified with nafion-DTPA-glycerol was used for the highly selective and sensitive determination of a trace amount of Cu$\^$2+/. Various experimental parameters, which influenced the response of nafion-DTPA-glycerol modified electrode to Cu$\^$2+/, were optimized. The copper(II) was accumulated on the electrode surface by the formation of the complex in an open circuit, and the resulting surface was characterized by medium exchange, electrochemical reduction, and differential pulse voltammetry, A linear range was obtained in the concentration range 1.0${\times}$10$\^$-8/M∼1.0${\times}$10$\^$-6/M Cu(II) with 7 min preconcentration. Further, when an approximate amount of lead(II) is added to the test solution, nafion-DTPA-glycerol modified glassy carbon electrode has a dynamic range of 2 orders magnitude(1.0${\times}$10$\^$-9/M∼1.0${\times}$10$\^$-7/M). The detection limit(3 $\sigma$) was as low as 5.0${\times}$10$\^$-6/M(0.032ppb). The interferences from other metal ions could be reduced by adding KCN into the sample solutions. This method was applied to the determination of coppe,(II) in certified reference material(3.23${\times}$10$\^$-7/M, 21ppb), sea water(9.50${\times}$10/sup-7/M, 60ppb). The result agrees satisfactorily with the value measured by Korea Research Institute of Standard and Science.