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Accurate signal transmission between neurons is accomplished by vesicle release with high spatiotemporal resolution in the central nervous system. The vesicle release occurs mainly in the active zone (AZ), a unique area on the presynaptic membrane. Many structural proteins expressed in the AZ connect with other proteins nearby. They can also regulate the precise release of vesicles through protein-protein interactions. RIM-binding proteins (RIM-BPs) are one of the essential proteins in the AZ. This review summarizes the structures and functions of three subtypes of RIM-BPs, including the interaction between RIM-BPs and other proteins such as Bassoon and voltage-gated calcium channel, their significance in stabilizing the AZ structure in the presynaptic region and collecting ion channels, and ultimately regulating the fusion and release of neuronal vesicles.

The aging behaviors of PMMA in liquid scintillator at different temperatures of 30 °C, 40 °C, 50 °C and 55 °C under static tensile stress were experimentally investigated with dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC), and the service life of the PMMA was predicted on the basis of the time-temperature superposition approach. The results showed that the higher the aging temperature, the faster the tensile strength of PMMA decreased. Acceleration of aging can be realized by applying high temperatures, and a master curve can be constructed using the time-temperature superposition concept. The linear behavior of the plot of the shift factors versus the inverse aging temperature indicated that the aging mechanism was consistent with Arrhenius's law, and the lifetime of PMMA was predicted to be 25 years at 20 °C. Keywords: PMMA, Tensile stress, Aging, Time-temperature superposition, Lifetime prediction, Liquid scintillator

We report quantitative measurement of terrace size as a function of annealing time for step bunching induced by direct current heating in the step-down direction for the temperatures 945°C and 1245°C. This result is shown to be inconsistent with simple models of step bunching in which there is a temperature-independent electromigration force on diffusing surface atoms. Deposition of Si atoms onto the surface held at 945°C with current running in the step-down direction slows the step bunching. By estimating the parameters governing step flow from experimental observations, this result is shown to be inconsistent with simple models of step bunching incorporating an electromigration force as the source of diffusional anisotropy. The evolution of step bunching was monitored by measuring the growth of the terrace sizes revealing a functional form of t α , with α ∼0.5.

Instabilities in step structure induced by direct-current heating have been measured using STM on Si(111) surfaces with an equilibrium step separation of approximately 1500 A. The two-dimensional structure of kinetically formed step bunches and associated “crossing arrays” of single-height steps shows qualitatively good agreement with predictions of a generalized theory of step-flow instability. Quantitative analysis of the structures is consistent with the theory. The result provides the first experimental determination of an effective anisotropy ratio governing kinetic step bunching. The measured value of this anisotropy ratio is 0.20 ± 0.03.

The structural stability of the Si(112) surface has been investigated using low-energy electron diffraction (LEED). Heating between 950° C and 1150° C causes faceting to the (111), (113), (525) and (255) surfaces unless great care is taken to prevent carbon contamination. Increasing the carbon concentration increases the extent of the faceting. Removal of the carbon by heating to 1250° C returns the surface orientation to (112).