TY - JOUR
T1 - Behavior of the thermal diffusivity of native and oxidized human low-density lipoprotein solutions studied by the Z-scan technique
AU - Santos, Priscila R.
AU - Genaro-Mattos, Thiago C.
AU - Monteiro, Andrea M.
AU - Miyamoto, Sayuri
AU - Neto, Antonio M.Figueiredo
N1 - Funding Information:
Authors acknowledge Dr. Fernando Batalioto for writing the code of the iterative method-fitting program. This study was supported by The National Counsel for Scientific and Technological Development (CNPq), São Paulo Research Foundation (FAPESP) and National Institute of Science and Technology of Complex Fluid (INCT-FCx) and Redoxoma (INCT-Redoxoma).
PY - 2012/10
Y1 - 2012/10
N2 - Modifications in low-density lipoprotein (LDL) have emerged as a major pathogenic factor of atherosclerosis, which is the main cause of morbidity and mortality in the western world. Measurements of the heat diffusivity of human LDL solutions in their native and in vitro oxidized states are presented by using the Z-Scan (ZS) technique. Other complementary techniques were used to obtain the physical parameters necessary to interpret the optical results, e.g., pycnometry, refractometry, calorimetry, and spectrophotometry, and to understand the oxidation phase of LDL particles. To determine the sample's thermal diffusivity using the thermal lens model, an iterative one-parameter fitting method is proposed which takes into account several characteristic ZS timedependent and the position-dependent transmittance measurements. Results show that the thermal diffusivity increases as a function of the LDL oxidation degree, which can be explained by the increase of the hydroperoxides production due to the oxidation process. The oxidation products go from one LDL to another, disseminating the oxidation process and caring the heat across the sample. This phenomenon leads to a quick thermal homogenization of the sample, avoiding the formation of the thermal lens in highly oxidized LDL solutions.
AB - Modifications in low-density lipoprotein (LDL) have emerged as a major pathogenic factor of atherosclerosis, which is the main cause of morbidity and mortality in the western world. Measurements of the heat diffusivity of human LDL solutions in their native and in vitro oxidized states are presented by using the Z-Scan (ZS) technique. Other complementary techniques were used to obtain the physical parameters necessary to interpret the optical results, e.g., pycnometry, refractometry, calorimetry, and spectrophotometry, and to understand the oxidation phase of LDL particles. To determine the sample's thermal diffusivity using the thermal lens model, an iterative one-parameter fitting method is proposed which takes into account several characteristic ZS timedependent and the position-dependent transmittance measurements. Results show that the thermal diffusivity increases as a function of the LDL oxidation degree, which can be explained by the increase of the hydroperoxides production due to the oxidation process. The oxidation products go from one LDL to another, disseminating the oxidation process and caring the heat across the sample. This phenomenon leads to a quick thermal homogenization of the sample, avoiding the formation of the thermal lens in highly oxidized LDL solutions.
KW - High-performance liquid chromatography
KW - Low density lipoprotein
KW - Oxidation
KW - Thermal diffusivity
KW - Thermal-lens
KW - Z-scan
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U2 - 10.1117/1.JBO.17.10.105003
DO - 10.1117/1.JBO.17.10.105003
M3 - Article
C2 - 23223997
AN - SCOPUS:84876531929
SN - 1083-3668
VL - 17
JO - Journal of Biomedical Optics
JF - Journal of Biomedical Optics
IS - 10
M1 - 105003
ER -