Magento-rheological Fluid (MRF) and Shear Thickening Fluid (STF) have separately attracted considerable interest due to their fast and reversible response to an external magnetic field or an abrupt shearing loading. In this paper we fabricated a combined phase of Magento-rheological Shear Thickening Fluid (MRSTF) such that it has an MR and a shear thickening effect. To fabricate it, 14 nm primary size fumed silica particles were suspended in ethylene glycol to form a 25% by weight fraction of STF base. Carbonyl iron particles (3-5 μm) were then mixed with the STF base to obtain four MRSTF samples with weight fractions of 5%, 10%, 20%, and 30%. The viscoelastic properties of all four samples, namely their steady state and dynamic behaviour, were investigated with a parallel-plate rheometer. The relevance of the dynamic behaviour to the stress amplitude, frequency, and external magnetic field were investigated and discussed. MRSTFs behave like linear viscoelastic materials for a small range of stress amplitudes, but at large stress amplitudes they are non-linear viscoelastic or viscoplastic, where the storage modulus gradually decreases with the stress amplitude. Within the linear viscoelastic range of shear stress, MRSTFs behave with linear viscoelastic properties as the frequency increases. MRSTFs also exhibit features of both components, but are more prone to MRF with the inception of external field excitations.

Merocyanine 540 (MC540) is a widely used dye probe for membranous environments. However, fundamental knowledge of the spectral features of this dye in aqueous and hydrophobic environments is still lacking. Such knowledge is important because biomembranes involve a hydrophobic environment surrounded by a hydrophilic environment. Because many investigations so far have been performed based on indistinct spectral estimations, the interpretation of the data obtained using this dye as a fluorescent transmembrane probe remains controversial. In order to determine the exact spectra in both aqueous and hydrophobic environments, we adopted principal factor analysis (PFA), a method of multivariate analysis. The PFA method can also determine the number of molecular species present in the reaction mixture, which is three in pure water and two in phospholipid suspension. Two of the species in both water and phospholipid suspension were the monomer and dimer. The third species in water was the trimer, but its amount was so small at 10 microM MC540 solution that the spectral data in water can be approximated neglecting this molecular species. The monomer spectrum changed its form markedly with a bathochromic shift when transferred from the water to phospholipid environment, whereas the dimer remained similar in its shape except for a remarkable red shift. In water, the dissociation constants, K(1) and K(2), for the assumed stacking-model reactions, M+M <--> M(2) and M+M(2) <--> M(3), were 3.1 x 10(-4) M and 5.7 x 10(-4) M, respectively. In the phospholipid environment, the dissociation constant K* for the assumed stacking-model reaction, M(*)+M(*) <--> *M(2), was 1.9x10(-5)M. The fluorescent intensities of MC540 were also measured in both water and phospholipid environments. A comparison based on the absorption and fluorescence spectra suggested that the temporal increase in the amount of the monomer on the excitable membrane contributes to the fluorescent intensity change observed in the transmembrane potential change.

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A dual molecular rotor N-adamantyl camphor sulfonamide (ADCS) consisting of adamantane (AD) and camphor (CA) linked by a sulfonamide (−SO2NH−) bond was designed to form a chiral plastic crystal. Chiral 1S-ADCS and racemic rac-ADCS crystals exhibited a phase transition from the crystal to the plastic crystal phase upon heating at approximately 400 K, as confirmed by optical, structural, and dielectric measurements. In the plastic crystal phase, both the AD and CA units have thermally activated motional freedom and their dynamics freeze to form a low-temperature plastic crystal phase rather than a crystal phase. The most stable and metastable ADCS conformations coexist in the as-grown crystalline phase, and the dynamic behavior of the plastic crystal phase makes it difficult to recover the initial conformations necessary for the formation of the closest packing structure upon cooling, resulting in a phase transition to the plastic crystalline state. The as-grown white crystals of both 1S-ADCS and rac-ADCS exhibited weak luminescence, whereas the phase transition from glass to transparent plastic crystals changed to a non-fluorescent state.