This paper presents the anomalous release kinetics of a cancer drug (prodigiosin) frompoly-n-isopropyl-acrylamide ( P(NIPA))-based gels. The release exponents, n, which correspond to the drug release mechanisms, were found to be between 0.41 and 1.40. This is within a range that include Fickian case I (n = 0.45) and non-Fickian diffusion (case II) (n > 0.45) for cylindrical drug-loaded structures. The results, however, suggest that the release exponents, n, correspond mostly to anomalous case II and super case II transport mechanics with sigmoidal characteristics. The drug release kinetics of the P(NIPA)-based hydrogels are well described by bi-dose functions. The observed drug release behavour is related to the porosity of the hydrogels, which can be controlled by cross-linking and copolymerization with acrylamide, which also improves the hydrophilicity of the gels. The paper also presents the effects of cancer drug release on cell survival (%), as well as the cell metabolic activities of treated cells and non-treated cells. The implications of the results are discussed for the development of implantable thermosensitive gels for the controlled release of drugs for localized cancer treatment.

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Surface and subsurface crack nucleation and growth mechanisms are elucidated for equiaxed (microstructure 1), elongated (microstructure 2), and colony (microstructure 3) microstructures of Ti6242. Prominent cleavage facets, indicative of a Stroh-type dislocation-pile phenomenon characterize the nucleation sites. Beachmarking and scanning electron microscopy (SEM) techniques are used to study fatigue crack growth rates and crack shape evolution in the short and long crack regimes. The studies reveal that surface crack growth rate data are generally comparable to the through-crack growth rate data in the long crack growth regime. However, the depth crack growth rates are somewhat slower than the through-crack growth rates. Surface crack evolution profiles are shown to exhibit a tendency towards “Preferred Propagation Paths” (PPPs). However, the magnitudes of the aspect ratios along the PPPs are different from those reported for square or rectangular cross sections subjected to cyclic tension or bending loads. Finally, the measured crack lengths and aspect ratios are compared with predictions obtained from a fracture mechanics model.