• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1135-1140
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• 2007

Pseudo-first-order rate constants (kobs) for the reaction of N-benzylphthalimide (NBPT) with HO- have been determined at 2.0 × 10?4 M NBPT, 1.0 × 10?3 and 2.0 × 10?3 M NaOH as well as varying concentrations of cetyltrimethylammonium bromide ([CTABr]T = 0.0-1.7 × 10?1 M). The effects of [CTABr]T ? CMC (with CMC representing the critical micelle concentration of CTABr) on kobs have been analyzed in terms of Berezin's pseudophase (BPP) model and pseudophase ion-exchange (PIE) model. Although both models give the best observed data fit with least-squares values not significantly different from each other, the calculated values of KS from BPP model appear to be more reliable compared to those from PIE model because the values of KS from BPP model are similar to the corresponding KS values determined spectrophotometrically.

• Biomedical Science Letters
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• v.1 no.1
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• pp.1-8
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• 1995

The present study was undertaken to determine the dissociation constant (Kd)of monoclonal antibody to human apolipoprotein A-I (apo A-I) using enzyme-linked immunosorbent assay (ELISA). First the monoclonal antibody was incubated in solution with the antigen until the equilibrium was reached; then the free antibody which remains unsaturated at equilibrium was captured by binding to antigen on the microtiter plate and be measured by a classical indirect ELISA. The value of Kd determined from Scatchard plot was 0.625$\times$10^{-9}$ for purified antibody and 0.720$\times$10$^{-9}$ for unpurified antibody. This method was valuable for the measurement of true dissociation constant and found to be simple, reproducible, and accurate.

• The Korean Journal of Nuclear Medicine
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• v.7 no.2
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• pp.1-12
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• 1973

The most commonly used methods for determining thyroxine binding globulin(TBG) concentration as the total thyroxine-binding capacity utilize electrophoretic seperation of serum. Although technically simple, the electrophoretic method is time consuming and is limited in the number of samples which can be run in a single assay. The author presented a single $T_4$ load ion exchange resin method as an approach to simplify the technique as with clinical practicability and results were analyzed. For construction of the standard curves, serum mixtures were diluted with barbital buffer.which effectively blocked $T_4$-binding to TBPA. For each serum dilution, a constant amount of $T_4-^{125}I$ and increments of unlabelled $T_4$ were added. After incubation in water bath, resin beads were dispensed to the samples which binded all $T_4$ not bound to TBG. The radioactivity in the supernatant was counted in the gamma scintillation counter. Each standard curve was plotted from the percent counts in the supernatant and total $T_4$ in each tube. Unknown samples were diluted to 1:40 and ran at a single $T_4$ loading concentration, and the TBG capacity of the samples was able to be read on the standard isobars. The following results were obtained. 1) Mean and standard deviation for TBG capacity in normal population was $28.6{\pm}5.09{\mu}g\;T_4/100ml$. 2) $24.9{\pm}3.87{\mu}g\;T_4/100ml$ in hyperthyroidism showed low TBG capacity comparing to normal population.(p<0.025) 3) $31.0{\pm}2.40{\mu}g\;T_4/100ml$ in hypothyroidism showed high TBG capacity tendency comparing to normal population. 4) Reversed correlationship existed between TBG capacity and $T_3$ resin uptake(r=-0.624), TBG capacity and serum $T_4$ value (r=-0.859), and TBG capacity and free thyroxine index(r=-0.623). The author assumes that this method of assay is considerably simpler in instrumentation and technique than any other assays traditionally being used, and seems to be more practical for routine clinical laboratory use.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.388-394
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• 1994

A Hg(0.79)Cd(0.21)Te single crystal has been grown by the Traveling Heater Method(THM). Its zinc blend cubic structure is identified from the X-ray diffraction patterns and its lattice constant is determined to be $6.464 {\AA}$ using the least-square method of Cohen. From the values of the lattice constant, the composition x is determined to be 0.21. The electron density is calculated from the relative intensities of the scattered X-ray and compared with the theoretically calculated values. From the electron density distribution, it is shown that the crystal binding of Hg(1-x)Cd(x)Te(MCT) is mainly covalent and has tetrahedron bonds between adjacent atoms.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.115-120
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• 1998

The $TiN_x$ thin films were prepared on glass substrate by RF(radio-frequency) magnetron sputtering apparatus from a Ti target in a gaseous mixture of argon and nitrogen. In deposition, a RF power supply was used as a power source with a constant power of 240W, and the substrate was heated to $200^{\circ}C$. The films were obtained at nitrogen flow rates in the range 3-9 seem with a constant argon flow rate of 20 seem. For the films obtained, the chemical binding energy of the films was investigated by XPS (x-ray photoelectron spectroscopy) in order to analyze the chemical nature and composition of the films.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1162-1168
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• 2015

Accelerated thermal aging of chlorosulfonated polyethylene (CSPE) was performed for 0 days, 80.82 days, and 161.63 days at 100℃, which is equivalent to 0 y, 40 y, and 80 y of aging, respectively, at 50℃. After freshwater flooding, the volume electrical resistivity of CSPE was highest after 180 days of drying, and its insulating property recovered when dried for more than 300 days. The dielectric constant of the CSPE was not measured after seawater flooding. The dielectric constant of the accelerated thermally aged CSPE was higher after freshwater flooding than that before seawater flooding. The bright, open pores of CSPE were converted into dark, closed pores after seawater flooding, and the dark, closed pores of the accelerated thermally aged CSPE samples were partly converted into bright, open pores after freshwater flooding. The apparent density of CSPE increased slightly whereas its elongation at break (EAB) decreased until 80 y of accelerated thermal aging before seawater flooding. The peak binding energies of oxygen in the non-accelerated and accelerated thermally aged CSPE for 40 y and 80 y were shifted by more than 1.0 eV after seawater and freshwater flooding. The CH2 content in the non-accelerated and accelerated thermally aged CSPE for 40 y and 80 y after seawater flooding for 5 days was lower than that before seawater flooding whereas atoms such as Cl, O, Pb, Al, Si, Sb, and S that are related to conducting ions such as Na⁺, Cl^-, Mg²⁺, SO4 ^2-, and K⁺ were relatively increased.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2419-2424
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• 2013

Guanosine-5'-diphosphate 3'-diphosphate (ppGpp) serves as alarmone in bacterial stringent responses. In this study, an affinity column was constructed by immobilizing ppGpp to NHS-Sepharose for isolating ppGpp-binding proteins. A novel ppGpp-binding protein, YjgA, was isolated and characterized by MALDI-TOF MS (matrix-assisted laser desorption ionization-time-of-flight mass spectrometry) coupled with two-dimensional gel electrophoresis. YjgA and truncated forms of YjgA were cloned and over-expressed in BL21 (DE3). The binding affinity of YjgA to ppGpp was determined by equilibrium dialysis. The interaction of YjgA with ppGpp was very specific, considering that the dissociation constant of YjgA with ppGpp was measured as $5.2{\pm}2.0{\mu}M$, while the affinities to GTP and GDP were about 60 and 30 times weaker than ppGpp. Expression of yjgA gene in Escherichia coli K-12 MG1655 was examined by reverse transcription polymerase chain reaction (RT-PCR). RT-PCR results revealed that yjgA was expressed from early to late stationary phase. The yjgA deletion mutant exhibited decreased cell number at stationary phase compared to parent strain and the over-expression of YjgA increased the cell number. These results suggested that YjgA might stimulate cell division under stationary phase. In most prokaryotic genome, about half of the protein candidates are hypothetical, that are expected to be expressed but there is no experimental report on their functions. The approach utilized in this study may serve as an effective mean to probe the functions of hypothetical proteins.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1599-1603
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• 2011

Novel chemosensors based on 2-(2'-hydroxyphenyl)quinoline were prepared and evaluated for sensing metal cations. The photophysical properties of chemosensors 1-3 were examined and their ion-selectivity was evaluated by measuring their fluorescent emission responses to alkali, alkaline earth, and transition metal ions. Chemosensors 1, 2 and 3 show ratiometric and enhanced fluorescence changes with transitional metals that are efficient fluorescence quenchers, especially 3 has a high binding constant with $Hg^{+2}$ in $CH_3CN$.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.483-487
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• 2015

The different calculated quantum chemical descriptors by DFT method were used for prediction of some sulphanilamide Schiff bases inhibitor activity as a binding constant (log K). Multiple linear regression (MLR) and artificial neural network (ANN) were employed for developing the useful quantitative structure activity relationship (QSAR) model. The obtained results presented superiority of ANN model over the MLR one. The offering QSAR model is very easy to computation and Physico-Chemically interpretable. Sensitivity analysis was used to determine the relative importance of each descriptor in ANN model. The order of importance of each descriptor according to this analysis is: molecular volume, molecular weight and dipole moment, respectively. These descriptors appear good information related to different structure of sulphanilamide Schiff bases can participate in their inhibitor activity.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.98-104
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• 1995

Recently murine monoclonal antibodies have been studied actively for radioimmuno-scintigraphy and radioimmunotherapy, especially on patients with leukemia and lymphoma. In this research, we studied radiolabeling and immunologic characteristics of two in-house anti-leukemic monoclonal antibodies(anti-CALLA & anti-JL-1 antibodies) to make the basis for their clinical application. Each antibody was radiolabeled successfully with $^{99m}Tc$ by pretargeting transchelation method and with $^{125}I$ by lodogen method. We also studied cell binding assay, Scatchard analysis and modulation phenomenon. $^{125}I$ showed 90% labeling efficiency for each anti-body which was satisfactory, but $^{99m}Tc$ showed labeling efficiency below 70%, for which we need better labeling method. In cell binding assay, the immunoreactivity(IR) was low for $^{99m}Tc$-labeled antibodies. Scatchard analysis showed satisfactory data for both binding affinity. The affinity constant and antibody binding sites per cell are around $10^9M^{-1}$ and $10^4$, respectively. There was no modulation phenomenon in cases of $^{125}I$ or $^{99m}Tc$ labeled antibodies. We expect that two anti-leukemic monoclonal antibodies may be useful in diagnosis and therapy for leukemia and lymphoma patients.