Surgical cotton microfibers loaded with proteins and apatite: A potential platform for bone tissue engineering.

Tissue engineering has emerged as the best alternative to replacing damaged tissue/organs. However, the cost of scaffold materials continues to be a significant obstacle; thus, developing inexpensive scaffolds is strongly encouraged. In this study, cellulose microfibers (C), gelatin (G), egg white (EW), and nanohydroxyapatite (nHA) were assembled into a quaternary scaffold using EDC-NHS crosslinking, followed by freeze-drying method. Cellulose microfibers as a scaffold have only received a limited amount of research due to the absence of an intrinsic three-dimensional structure. Gelatin, more likely to interact chemically with collagen, was used to provide a stable structure to the cellulose microfibers. EW was supposed to provide the scaffold with numerous cell attachment sites. nHA was chosen to enhance the scaffold's bone-bonding properties. Physico-chemical, mechanical, and biological characterization of scaffolds were studied. In-vitro using MG-63 cells and in-ovo studies revealed that all scaffolds were biocompatible. The results of the DPPH assay demonstrate the ability of CGEWnHA to reduce free radicals. The CGEWnHA scaffold exhibits the best properties with 56.84 ± 28.45 µm average pore size, 75 ± 1.4 % porosity, 39.23 % weight loss, 109.19 ± 0.98 kPa compressive modulus, and 1.72 Ca/P ratio. As a result, the constructed CGEWnHA scaffold appears to be a viable choice for BTE applications.

Thermal, mechanical, and dielectric properties of high performance PEEK/AIN nanocomposites.

The mechanical, thermal, and dielectric properties of novel high performance poly(ether-ether-ketone) (PEEK)/AIN nanocomposites were discussed. The stiffness of the nanocomposites was significantly improved in the glassy state as well as rubbery state. The coefficient of thermal expansion (CTE) of the nanocomposites was found substantially lower than that of pure PEEK. The glass transition temperature and melting temperature of the nanocomposites were increased significantly. The thermal stability and dielectric constant of the nanocomposites were increased slightly with AIN content. The significant improvement in the properties of the nanocomposites was attributed to the good adhesion between the AIN nanoparticles and the polymer matrix. The fabricated nanocomposite is very promising for use in electronics packaging substrate as an alternative substrate owing to its good thermal, mechanical and dielectric properties.

Photoinduced effects in the vicinity of the smectic-A-smectic-C*A transition: polarization, tilt angle, and response time studies.

We report detailed measurements of the photoinduced effects on the electric polarization, tilt angle, response time, and rotational viscosity in the vicinity of the smectic-A-antiferroelectric-smectic-C (Sm-C*(A)) transition of a guest-host system consisting of photoactive azobenzene-based guest molecules and nonphotoactive host molecules. In the Sm-C*(A) phase all the parameters, except the tilt angle, exhibit both the primary and secondary photoferroelectric effects. The tilt angle dependence of the polarization in the absence of light and in light-on conditions have been analyzed in terms of the predictions of the generalized mean-field and microscopic models.

Time-resolved measurements of the dynamics of the photoinduced smectic-C* alpha-smectic-A transition.

We present the study of the dynamics of the recently reported photoinduced smectic-C(*)(alpha)-smectic-A transition. High resolution time-resolved dielectric dispersion measurements carried out during the photoisomerization process demonstrate that the magnitude of the uv intensity mimics the role played by temperature in determining the behavior of the soft mode relaxation. We also show that the uv intensity dependence of the soft mode relaxation frequency f(R) in the photoinduced smectic-A phase can be described with a functional form similar to that derived for the temperature dependence of f(R) and compare the experimentally determined critical exponent with the theoretically predicted for the Ising and three-dimensional XY universality classes. Our study illustrates an interesting feature, namely, the magnitude of light intensity can be treated like a thermodynamic variable such as temperature and pressure to study phase transitions in general.

Photoinduced effects in the vicinity of the smectic-C(*)(alpha)-smectic-A transition.

We report the first results of photoinduced effects near the smectic-C(*)(alpha)-smectic-A transition in a binary liquid crystalline material. Dielectric dispersion measurements show that the softening of the tilt fluctuation mode in the vicinity of the transition gets enhanced in the presence of the UV light.