Vitaly Buckin

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High-resolution ultrasonic spectroscopy was applied to analyse a pseudo-ternary phase diagram for a mixture consisting of water/ethyl oleate/Tween 80 and Span 20 at 25 degrees C. The measured changes in the ultrasonic velocity and attenuation with concentration of water in oil/surfactants mixtures showed several, well defined stages and transitions between(More)
In the present work, high-resolution ultrasonic spectroscopy was applied to analyze a pseudoternary phase diagram for mixtures consisting of water/isopropyl myristate/Epikuron 200 and a cosurfactant (n-propanol). Changes in the ultrasonic velocity and attenuation in the megahertz frequency range were measured in the course of titration of the(More)
Dynamics of micro-structural changes in milk during the renneting process were analysed using high-resolution ultrasonic spectroscopy in combination with dynamic rheology and NIR transmission measurements. Two independent ultrasonic parameters, velocity and attenuation were measured in the frequency range 2 to 15 MHz, as a function of time after addition of(More)
The interaction of hexamminecobalt(III), Co(NH(3))(6)(3+), with 160 and 3000-8000 bp length calf thymus DNA has been investigated by circular dichroism, acoustic and densimetric techniques. The acoustic titration curves of 160 bp DNA revealed three stages of interaction: (i) Co(NH(3))(6)(3+) binding up to the molar ratio [Co(NH(3))(6)(3+)]/[P] = 0.25, prior(More)
Different DNA sequences have different physical properties, which seem to be important for their biological function. In particular, (dA)n.(dT)n has many unusual features, which include resistance to conformational changes in a variable chemical environment, an unusual thermodynamics of interaction with ligands, and the inability to reassociate into(More)
In the present paper we describe the application of the thickness shear mode resonator technique for the measurement of viscoelastic parameters of milk and acidified milk gels in the megahertz frequency range. The technique provides information on the viscoelasticity of milk and milk gels in the time scale of 10(-8) to 10(-7) s. The length scale of the(More)
Apparent molar adiabatic compressibilities and apparent molar volumes of poly[d(A-T)].poly[d(A-T)], poly(dA).poly(dT), DNA and poly(A).poly(U) in aqueous solutions were determined at 1 degree C. The change of concentration increment of the ultrasonic velocity upon replacing counter ion Cs+ by the Mg2+ ion was also determined for these polymers. The(More)
High-resolution ultrasonic spectroscopy (HR-US) was applied for real-time analysis of enzymatic hydrolysis of cellobiose by a β-glucosidase from Aspergillus niger (Novozyme 188) at 50°C and pH 4.9. This technique is noninvasive, it does not require optical transparency and is suitable to continuously monitor the time dependence of the reaction progress in a(More)
The concentration increment of the ultrasound velocity has been measured with an accuracy of +/- 0.03 cm/s in dilute aqueous solutions of a variety of nucleic bases and their derivatives in the concentration range 0.5-1.5 mg/g H2O at temperatures of 15-35 degrees C. A new method for the precise measurement of ultrasound velocity in small volumes of liquids(More)
The paper introduces ultrasonic technology for real-time, nondestructive, precision monitoring of enzyme-catalyzed reactions in solutions and in complex opaque media. The capabilities of the technology are examined in a comprehensive analysis of the effects of a variety of diverse factors on the performance of enzyme β-galactosidase in formulations for(More)