ABSTRACT
Abstract Lipoprotein monitoring is desirable in the management of medical conditions such as atherosclerotic cardiovascular disease and coronary artery disease, in which controlling the concentration of these chylomicrons is crucial. Current clinical methods are complex and present poor reproducibility between laboratories. For these reasons, recent guidelines discard the assessment of low-density lipoprotein cholesterol (LDL-C) as a routine analysis during lipid-lowering therapies. Concerning the importance of monitoring this parameter, the authors present an electrochemical immunosensor constructed from a simple and easy-to-reproduce platform that allows detecting and quantifying LDL nanoparticles directly from human serum samples. The performance of the biosensor was studied by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The biosensing platform displays good stability and linearity between 30 mg dL-1 and 135 mg dL-1 with a detection limit of 20 mg dL-1. The proposed biosensor can be easily employed for monitoring LDL concentration in clinical treatments.
Subject(s)
Phase Transition , Lipoproteins, LDL/analysis , Microscopy, Electron, Scanning/methods , Electrochemistry/instrumentation , Dielectric Spectroscopy/methods , Hypercholesterolemia/classificationABSTRACT
ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.
Subject(s)
Zirconium/chemistry , Acidulated Phosphate Fluoride/chemistry , Surface Properties/drug effects , Time Factors , X-Ray Diffraction/methods , Materials Testing , Microscopy, Electron, Scanning , Dental Implants , Ceramics/chemistry , Corrosion , Dielectric Spectroscopy/methods , ImmersionABSTRACT
Serum iron, zinc and copper concentrations in Rheumatoid Arthritic [RA] patients as compared to normal controls were measured. Serum calcium, magnesium, phosphorus concentrations, and alkaline phosphatase activity as well as 1, 25 [OH][2] Vitamin D in RA patients as compared to normal controls were measured. In addition, Hemoglobin derivatives, and the dielectric relaxation in the frequency range 100 KHz up to 10 MHz of Hb molecules of RA patients compared to normal controls were measured. It was found that a significant increase in Met-Hb, abnormal dynamic motion of Hb and changes in the overall shape of Hb. Also, The dielectric results indicated that the molecular shape of hemoglobin tends to deviate from the spherical form as the disease geos to the severity