Nematic-smectic a transition entropies in a homologous series

We have measured the nematic-smectic A transition entropies in the homologous series 4-n-alkoxybenxylidene-4′-phenylazoaniline. The results agree very well with the McMillan theory without the isotropic attraction between the molecules.     

Anisotropy of the self-diffusion tensor in nematic MBBA

The temperature dependence of the anisotropy of the self-diffusion constant tensor in nematic DMBBA was determined by a multiple pulse NMR spin echo technique. The measured anisotropy $\text{D}{}_6\text{D⊥}\text{= 1.4}$ in the partially ordered nematic system was related to the anisotropy $\text{D}{}_{\mathrm{O}}\text{6}\text{D}{}^{\mathrm{O}}\text{⊥}\text{= 2.2}$ in the perfectly ordered system.     

An isotopic effect in the dielectric spectra of Ark. 9/water systems

Dielectric spectra of H₂O and D₂O molecules in the L_α liquid crystalline phase of nonylphenoxy-poly(ethylenoxy)ethanol(Ark. 9)/water lyotropic systems have been investigated by dielectric time domain spectroscopy in the frequency range from 10 MHz to 10 GHz. By fitting the Cole-Cole formula to the dielectric spectra, obtained at different temperatures the dielectric increments, the relaxation times and the distribution parameters have been calculated. A strong retardation of water molecules has been found for the lamellar phase with low water content, i.e. 10 water molecules (H₂O or D₂O) per one Ark. 9 molecule. The relaxation times obtained at room temperature for the light and heavy water are 63 and 93 ps, respectively. It means that the retardation factor for D₂O molecules in the L_α phase is close to 1.5 and higher than that found for pure heavy water (1.25). Any decomposition of the dielectric spectra obtained seems to be unsubstantiated. The temperature dependences of the relaxation times acquired for both kinds of water obey the Arrhenius behaviour.     

The unique role of nanoparticles in nanomedicine: imaging, drug delivery and therapy

This critical review will present the role of nanoparticles (NPs) in the directions that are vital to the new field of nanomedicine, including imaging and drug delivery. We reflect on the physical properties that make NPs advantageous for in vivo efficacy, and review recent advances in major NP based biomedical applications. Critical questions of transport, uptake, and clearance will be discussed and illustrated through the success and opportunities of NP imaging and therapy on a photodynamic therapy (PDT) based NP system that has been developed in our lab over the past decade (540 references).