• Journal of Forest and Environmental Science
• /
• 제31권4호
• /
• pp.280-287
• /
• 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.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
• /
• pp.161-161
• /
• 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.

• 약학회지
• /
• 제28권3호
• /
• pp.129-138
• /
• 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.

• 한국잠사학회:학술대회논문집
• /
• 한국잠사학회 2003년도 제46회 춘계 학술연구 발표회
• /
• pp.80-80
• /
• 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
• /
• 제14권6호
• /
• pp.692-696
• /
• 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.

• 한국동물학회지
• /
• 제30권2호
• /
• pp.167-176
• /
• 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
• /
• 제16권3호
• /
• pp.205-210
• /
• 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.

• 분석과학
• /
• 제22권5호
• /
• pp.355-359
• /
• 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
• /
• 제22권4호
• /
• pp.227-235
• /
• 1997

병원내 방사선 작업 종사자 51명(진단방사선과 18명, 치료방사선과 17명, 핵의학과 16명)에서 림프구의 염색체이상 빈도를 대조군 49명과 비교하여 저선량 만성피폭시 인체에 미치는 영향을 조사하였다. 종사자의 축적선량은 0.30-40.07 mSv 였으며 총축적선량 5 mSv 이하가 46%로 가장 많았다. 염색체 이상이 있는 세포수는 종사자군에서 1.275%로, 대조군에서의 0.677%에 비해 더 높았다(p<0.001). 염색분체형 이상은 종사자군이 약간 높은 경향은 있지만 통계적인 유의성은 없었으며, 염색체형 이상은 대조군 $0.344{\times}10^{-2}$/cell에 비해 종사자군이 $0.706{\times}10^{-2}$/cell로 2.1배 높았다(p<0.05). 이중 교환은 대조군 $0.083{\times}10^{-2}$/cell에 비해 종사자군 $0.245{\times}10^{-2}$/cell로 3.0배 높았다(p<0.05). 총축적선량, 최근 5년 및 최근 2년간의 선량은 염색체이상과 선량-반응 관계가 없었으나, 최근 1년간 피폭선량과 염색체형 교환 빈도사이에 유의한 상관관계가 있었다(p<0.05). 근무년수와 염색체 이상빈도와 선량-반응관계는 없었으며, 각 작업부서 별 염색체이상 빈도 및 대조군과의 비교시, 염색체형 교환이 핵의학과 $0.313{\times}10^{-2}$/cell로 가장 높았으며 (p<0.05), 치료방사선과 근무자 $0.265{\times}10^{-2}$/cell (p=0.0622), 진단방사선과 근무자 $0.167{\times}10^{-2}$/cell (p=0.1107)순이었다. 색체이상이 유발될 수 있음을 확인하였으며, 따라서 림프구 염색체이상은 매우 낮은 양의 방사선 피폭에 의하여도 발생함을 알 수 있었다.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
• /
• pp.177-180
• /
• 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.