Jae Cheol Kwak

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Zn2+ binding to the anticoagulant heparin was examined using a dye spectrophotometric method, with added NaCl concentrations of 0.005, 0.0075, 0.01, 0.02 and 0.04 mol/l. The results are shown as Scatchard plots and demonstrate the entropy-driven anticooperativity of Zn2+ binding to heparin. From these Scatchard plots, intrinsic binding constants are(More)
Measurements of magnesium and calcium ion activities in solutions of the polyelectrolyte dextransulfate, with added sodium chloride or potassium chloride are presented. A two wavelength dye spectrophotometric method is used. Dextransulfate concentrations Cp (expressed as moles sulfate ion/litre) vary between 0.001 and 0.007, total ionic strengths between(More)
This paper compares two liquid introduction atmospheric pressure ionization techniques for the analysis of alkyl ethoxysulfate (AES) anionic surfactant mixtures by mass spectrometry, i. e., electrospray ionization (ESI) in both positive and negative ion modes and atmospheric pressure chemical ionization (APCI) in positive ion mode, using a triple quadrupole(More)
Isotherms for the binding of dodecyltrimethylammonium (DTA+) and tetradecyltrimethylammonium (TTA+) ions by DNA in aqueous solution at 30 degrees C are reported. The binding isotherms were determined using a potentiometric technique with cationic surfactant-selective electrodes. The DNA concentrations used are 5 X 10(-4) and 10(-3) equiv./kg, surfactant(More)
Query graph (QG) is an easy-to-use visual query language which facilitates formulating a query. Unlike relational databases, in object-oriented databases (OODBs), the basic entity of QG, i.e. a class, may consist of several entities to which the operations of a query actually apply, which causes the increase of query complexity and lack of expressiveness.(More)
Mean molal activity coefficients of simple electrolyte in aqueous solutions of Li, Na, K or Cs salts of dextransulfate (DS) with added LiCl, NaCl, KCl or CsCl are reported. The measurements were carried out by means of an electrochemical cell method using a cation exchange membrane as cation selective electrode and Ag/AgCl electrodes. For LiDS-LiCl,(More)
A dual-wavelength dye spectrophotometric method is reported for measuring zinc and manganese activities using the dyes tetramethylmurexide (TMMX) and murexide (MX) respectively. The method is applied to the measurement of the activities of these metal ions in solutions of the polyelectrolyte dextransulfate with added sodium chloride. Polyion concentrations,(More)
The dye spectrophotometric method for the measurement of the activity of divalent metal ions in polyelectrolyte solutions containing added electrolytes is discussed. The method is applied to mixtures containing the dextransulfate polyanion, NaCl, and MgCl2 or Ca2. A two wavelength ratio method as applied to polyelectrolyte solutions is compared to the(More)
Measurements of the equivalent conductivity of aqueous solutions of alkalimetal salts of a number of ionic polysaccharides at 25 degrees C are reported. The polysaccharides studied are: (1) three carboxymethylcelluloses of various degrees of substitution (Li+, Na+, Cs+ salts) in the concentration range 4 X 10(-4) - 6 X 10(-2) equivalents alkali ion per(More)