Effects of Imprinting and Water Activity on Transesterification and Thermostability with Lipases in Ionic Liquid

The effect of bio-imprinting and water activity on catalytic activities and the thermostability of lipases was investigated for transesterification using vinyl acetate and benzyl alcohol as substrates in ionic liquid, [Cnmim][PF6] (n=4,6,8), and benzene. The catalytic activities were enhanced by imprinting in benzene and [C4mim][PF6], and the relations between the transesterification activities and the water activity in both solvents were approximately bell shaped. The reactivity of the transesterification in benzene was higher than that in [C4mim][PF6]. The effects of water activity and imprinting on the kinetic parameters in [C4mim][PF6] were examined. Without controlling the water content, the values of Km,VA and Km,BA (Michaelis constants of vinyl acetate and benzyl alcohol, respectively) decreased, and the values of Vm (maximum rate) increased by imprinting. On the other hand, by controlling the water content in the organic media, the values of Vm, Km,VA, and Km,BA increased by imprinting. The activities of lipase in ionic liquid are more strongly affected by water activity and imprinting than those in benzene. We observed effects of water activity on thermostability but none from imprinting. This work is licensed under a Creative Commons Attribution 4.0 International License

Toward the beta-FeSi2 p-n homo-junction structure

ArticleTHIN SOLID FILMS. 515(22): 8210-8215 (2007)journal articl

Enhanced Esterification Activity and Thermostability of Imprinted Poly(Ethylene Glycol)-Lipase Complex

Although the range of applications for enzymatic reactions in organic solvents is rapidly expanding, this study focused on the enzymatic activity in the esterification of lauric acid with benzyl alcohol, and thermostability of lipase using poly(ethylene glycol) (PEG)-lipase complex and molecular imprinting techniques. The catalytic activity was enhanced through molecular imprinting and the PEG-lipase complex. The imprinting operation was particularly effective for catalytic activity after forming the PEG-lipase complex. The kinetic analysis of the lipase-catalyzed esterification revealed that the increase in esterification rate with imprinted lipases was mainly due to the higher maximum rate achieved by the system. The thermostability of the lipases was significantly improved by imprinting at all temperatures (50~70 °C). After forming a PEG-lipase complex, the imprinted lipase exhibited much higher reactivity and thermostability compared to the native lipase and the imprinted PEG-lipase complex

Variational Monte Carlo Study of the Kondo Necklace Model with Geometrical Frustration

We investigate the ground state of the Kondo necklace model on geometrically-frustrated lattices by the variational Monte Carlo simulation. To explore the possibility of a partially-ordered phase, we employ an extension of the Yosida-type wave function as a variational state, which can describe a coexistence of spin-singlet formation due to the Kondo coupling and magnetic ordering by the Ruderman-Kittel-Kasuya-Yosida interaction. We show the benchmark of the numerical simulation to demonstrate the high precision brought by the optimization of a large number of variational parameters. We discuss the ground-state phase diagram for the model on the kagome lattice in comparison with that for the triangular-lattice case.Comment: 3 pages, proceedings for ICHE201

Layer-specific morphological and molecular differences in neocortical astrocytes and their dependence on neuronal layers

Non-pial neocortical astrocytes have historically been thought to comprise largely a nondiverse population of protoplasmic astrocytes. Here we show that astrocytes of the mouse somatosensory cortex manifest layer-specific morphological and molecular differences. Two- and three-dimensional observations revealed that astrocytes in the different layers possess distinct morphologies as reflected by differences in cell orientation, territorial volume, and arborization. The extent of ensheathment of synaptic clefts by astrocytes in layer II/III was greater than that by those in layer VI. Moreover, differences in gene expression were observed between upper-layer and deep-layer astrocytes. Importantly, layer-specific differences in astrocyte properties were abrogated in reeler and Dab1 conditional knockout mice, in which neuronal layers are disturbed, suggesting that neuronal layers are a prerequisite for the observed morphological and molecular differences of neocortical astrocytes. This study thus demonstrates the existence of layer-specific interactions between neurons and astrocytes, which may underlie their layer-specific functions