Low Frequency Dielectric and Optical Behavior on Physicochemical Properties of Hydroxyapatite/Cornstarch Composite.

An investigation on relationship among the physicochemical, optical and dielectric properties of the hydroxyapatite/cornstarch (HA/Cs) composites with the starch proportion of 30, 40, 50, 60, 70, 80 and 90 wt% is presented in this work. The HA/Cs composites have been characterized via FTIR, XRD, DRS and impedance analyzer. This work depicts that the strong interaction is exhibited between the hydroxyapatite nanoparticles and starch as the starch proportion increases. This increment trend results in the higher crystallinity of the HA/Cs composites. The highly crystallized HA/Cs with hydroxyapatite nucleation center presents low optical properties (diffuse reflectance and optical band gap energy). The HA/Cs composite with 80 wt% starch proportion (H2C8) show higher dielectric properties (dielectric constant, loss factor and conductivity) due to the stronger interfacial interaction and close-packed HA/Cs crystalline structure. The relationship among the physicochemical, optical and dielectric properties of the HA/Cs composite is studied in this work for potential of instrumentation design.

Dielectric and material analysis on physicochemical activity of porous hydroxyapatite/cornstarch composites.

This paper provides a comprehensive analysis of the dielectric and physicochemical properties of the porous hydroxyapatite/cornstarch (HAp/Cs) composites in a new perspective. The porous composites have been characterized via SEM, FTIR, XRD and dielectric spectroscopy. The dielectric permittivity spectra were obtained in Ku-band (12.4-18.0 GHz) and it was correlated with the physicochemical properties of the porous HAp/Cs. Porous HAp/Cs composites exhibits low ε' and negative ε″, which influenced by the microstructural morphology, interaction between Hap and Cs, as well as crystalline features due to the various proportion of the HAp/Cs. The physicochemical effect of the composites results in the dielectric polarization and energy loss. This phenomenon indicates the presence of the three obvious relaxation responses in the ε' spectrum (13.2-14.0, 15.2-16.0, and 16.6-17.4 GHz) and the negative behaviours in the ε″ spectrum. The relationships between physicochemical and dielectric properties of the porous composite facilitate the development of the non-destructive microwave evaluation test for the porous composite.

Human respiratory epithelial cells from nasal turbinate expressed stem cell genes even after serial passaging.

Current development in the field of tissue engineering led to the idea of repairing and regenerating the respiratory airway through in vitro reconstruction using autologous respiratory epithelial (RE). To ensure the capability of proliferation, the stem cell property of RE cells from the nasal turbinate should be evaluated. Respiratory epithelial cells from six human nasal turbinates were harvested and cultured in vitro. The gene expression of FZD-9 and BST-1 were expressed in passage 2 (P2) and passage 4 (P4). The levels of expression were not significant between both passages. The RE cells exhibit the stem cell properties, which remains even after serial passaging.