The synthesis of a mg amount of pure argon containing fullerene allowed the synthesis of the first endohedral superconductors with critical temperatures lower than expected, an indication of the strong influence of the argon atom on the C60 cage.

The photo-intermediate state of bacteriorhodopsin is a metastable state that spontaneously transforms to the ground state over the energy barrier of a local minimum. As the recovery of the photocycle to the ground state and irreversible photobleaching to the denatured state may occur from the same local energy minimum, depending on the temperature, the structural stability of bacteriorhodopsin under illumination at high temperature was measured in order to study the intra- and inter-molecular interactions that contribute to the recovery of the ground state. Visible CD spectra of bacteriorhodopsin began to change at 60 degrees C from a bilobed to positive type in accordance with an appearance of an absorption peak at 470 nm. Irreversible photobleaching, the light-induced denaturation, also started to occur at 60 degrees C, suggesting some correlation between irreversible photobleaching and the structural change to the high-temperature intermediate state. However, bacteriorhodopsin in the dark was stable up to 70 degrees C, suggesting that there is some additional factor that lends structural stability to bacteriorhodopsin in the dark. The contribution of protein-protein interactions to stability is discussed on the basis of the difference in the denaturation behaviors between light and dark conditions.

Heterogeneity in the state of bacteriorhodopsin in purple membrane was studied through temperature jump experiments carried out in darkness and under illumination with visible light. The thermal denaturation, the irreversible component of spectral change at high temperature, had two decay components, suggesting that bacteriorhodopsin in purple membrane has heterogeneous stability. The temperature dependence of kinetic parameters under illumination revealed that the fast-decay component gradually increased at above 60 degrees C, indicating that the proportion of unstable bacteriorhodopsin increased. Significant change in the visible circular dichroism (CD) spectra was observed in darkness in the same temperature range as the increase of the fast-decay component under illumination. Denaturation experiments for C-terminal-cleaved bacteriorhodopsin showed that the C-terminal segment had some effect on the structural stability of bacteriorhodopsin under illumination. Dynamic and static models of the inhomogeneous stability of bacteriorhodopsin in purple membrane are discussed on the basis of the results of the denaturation kinetics and the visible CD spectra.

We discuss that β-Cu1.8Zn0.2V2O7 exhibits a large negative thermal expansion (NTE) behavior with a wide operating temperature window. The crystallographic parameters obtained by synchrotron x-ray diffraction experiments indicate that the volume contraction of β-Cu1.8Zn0.2V2O7 remains at most Δv/v = 0.83%. In contrast, the dilatometry measurements show T-linear NTE behavior from 100 K to 700 K and a large volume contraction of ΔV/V = 2.16% on heating from 200 K to 700 K. This discrepancy indicates that NTE in β-Cu1.8Zn0.2V2O7 is enhanced by the microstructural effect, similar to that employed for explaining the colossal NTE behavior in layered ruthenates. We further discuss that β-Cu1.8Zn0.2V2O7 is free from expensive and toxic elements, making it a potential candidate for practical NTE materials.