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ABSTRACT: In this study, we analyzed the effect of water and frequency on the dielectric properties of the nail plate in healthy individuals and in diabetic patients. The temperature dependencies of the loss tangent for both healthy and diabetic nail represent the relation between the electrical energy lost and stored in keratin-glucose-water complexes of this tissue. The differences between these materials concern the temperature ranges in which there appears the decomposition of loosely bound water. The effect of glycation on the loss tangent of the wet and the dry nail is supported by higher values of this parameter than in those describing the healthy samples in the whole temperature range and above 100°C, respectively. In addition, glycation lead to distinct increase in the dielectric relaxation decrement in permittivity and dielectric loss between the frequency of 500Hz and 100kHz for the wet and the dry nail. The results of this study indicate that the dielectric spectroscopy may be useful in observing the decomposition of water in the diabetic nail plate.
Colloids and surfaces. B, Biointerfaces 04/2013; 109C:143-146. · 2.60 Impact Factor
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ABSTRACT: The temperature and frequency dependencies of the dielectric parameters for the rat artery are used to analyse effects of hypothermia on this tissue. Measurements were performed over the frequency range 500Hz to 100kHz and at temperatures from 19 to 60°C. The artery samples contained about 12% water by mass at room temperature at a relative humidity of 70%. The frequency dependencies of the loss tangent for the control, mild hypothermic and moderate hypothermic artery exhibit two peaks at 2kHz and 35kHz in the α-dispersion region. The results were discussed in terms of the distribution of relaxation frequencies and the activation energy for the conduction and polarization mechanisms particularly in the elastin-water and collagen-water systems. The knowledge about dielectric behavior of the hypothermic rat artery in vitro is important due to clinical application of local and systemic hypothermia.
Colloids and surfaces. B, Biointerfaces 06/2012; 101C:1-5. · 2.60 Impact Factor
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ABSTRACT: In this work, we have carried out a dielectric study to determine the effect of tobacco smoke on the rat corneal function. Measurements were performed over the frequency range of 500 Hz-100 kHz in air and at the temperature of 35°C. The frequency dependencies of the loss tangent for both healthy and smoky cornea exhibit two peaks with different width occurring as a narrow at 2 kHz and a broad at around 16 kHz. The distribution parameter α at 2 kHz has a value of about 0.3, which increases to 0.6 at 16 kHz. The magnitude of the permittivity decrement at 2 and 16 kHz is about two and four times higher, respectively, for the smoky cornea than that for the healthy one. These dielectric studies indicate that the present method is useful in detection of the effect of tobacco smoke exposure on the corneal behavior.
Colloids and surfaces. B, Biointerfaces 02/2012; 90:109-12. · 2.60 Impact Factor
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ABSTRACT: In the course of the study, we carried out a dielectric examination to determine the effect of diabetes mellitus on the rat corneal function. Measurements were performed over the frequency range of 500 Hz-100 kHz in air and at the temperatures from 25 to 150°C. The frequency dependencies of the loss tangent for the healthy and the diabetic cornea exhibit two peaks at 2 kHz and 16 kHz in the α-dispersion region. The amplitude of these both peaks is smaller for the diabetic cornea than that for the healthy one. The temperature dependencies of the loss tangent for the healthy and the diabetic cornea reveal β-relaxation in the range of 30-70°C and 50-90°C, respectively. The present study exhibits that the dielectric spectroscopy is useful in detection of the effect of diabetes mellitus on the corneal molecular behavior.
Colloids and surfaces. B, Biointerfaces 11/2011; 91:266-8. · 2.60 Impact Factor
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ABSTRACT: This paper reports on the effect of paracetamol on the dielectric behavior of the rabbit lens. Measurements were performed over the frequency range of 100 Hz-100 kHz in air and at the temperature of 35°C. The frequency dependencies of the relative permittivity and dielectric loss for the control and paracetamol-control lenses are described in terms of a power-low, Debye and Cole-Cole relations. The effect of paracetamol on the dielectric properties of the lens is visible in the lower values of the relative permittivity than those for the control sample at the same frequency. In addition, the relaxations around 18 and 46 kHz for the paracetamol-control lens are shifted to lower frequencies compared with the control lens. The results of this work indicate that the present method is useful in detection of the lens toxicity elicited by overdoses of paracetamol in animal.
Colloids and surfaces. B, Biointerfaces 05/2011; 84(1):131-4. · 2.60 Impact Factor
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ABSTRACT: The influence of diabetes mellitus on dielectric properties of the human fingernail was measured in vitro in the alpha-dispersion region. The frequency dependencies of the permittivity and conductivity for the healthy and the diabetic nail plate revealed three separate relaxations, which were similar for both materials. Significant differences were observed in the values of permittivity at the same frequency between the healthy and the diabetic nails with low water content of about 0% and 3%. Results of this paper suggest that hyperglycemia alters the first-order structure of the nail keratin macromolecule.
Colloids and surfaces. B, Biointerfaces 12/2008; 69(1):91-4. · 2.60 Impact Factor
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ABSTRACT: Dielectric measurements as a function of temperature (22–200 °C) and frequency (100 Hz–100 kHz) are reported for the healthy and the diabetic nail plate. The plots of the relative permittivity versus temperature at the same frequency are higher in the healthy than in the diabetic nail. These results are interpreted as caused by the damage of the polar sites in the keratin–matrix–water system of the diabetic nail. The activation energy of the β-relaxation is higher for the diabetic nail than for the healthy nail, suggests that advanced glycation end products (AGEs) may form cross-links by interaction with keratin. The results of this work indicate that the dielectric measurements of the nail could be used in detection of diabetes.
Journal of Non-Crystalline Solids 355:2456-2460. · 1.54 Impact Factor
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ABSTRACT: The temperature and frequency dependencies of the dielectric parameters for the human fingernail are used to analyse keratin degradation in high temperatures. Measurements were performed over the frequency range of 100 Hz to 100 kHz and at temperatures from 22 to 260 °C. The nail samples contained 11% water by mass at room temperature at a relative humidity of 70%. The results were discussed in terms of the distribution of relaxation frequencies and the activation energy for the conduction and polarization mechanisms in the keratin–water system. The information on the dielectric behavior of the keratin degradation might become handy in course of future research on biomaterials obtained from nail keratin.
Thermochimica Acta 506:73-76. · 1.80 Impact Factor
