Monotosylated α- and β-cyclodextrins prepared in an alkaline aqueous solution

In order to establish the tosylated positions of α- and β-cyclodextrins, ¹³C-nmr spectra for the monotosyl-derivatives prepared in an alkaline aqueous solution were examined and determined to be in the 6-position of one glucose unit for β-cyclodextrin and to be in the C-2 position for α-cyclodextrin.     

The cyclodextrin-nicotinamide compound as a dehydrogenase model simulating apoenzyme-coenzyme-substrate ternary complex system

The cyclodextrin-dihydronicotinamde had a dihydronicotinamde group at the open side of cyclodextrin cavity, and showed a large rate enhancement in the reduction of substrate upon complexation comparing with NADH.     

Selective separation of hydroxy polychlorinated biphenyls (HO-PCBs) by the structural recognition on the molecularly imprinted polymers: direct separation of the thyroid hormone active analogues from mixtures

We developed novel separation media for hydroxy polychlorinated biphenyls (HO-PCBs) using the molecular imprinting techniques. The results of evaluation for the molecularly imprinted polymers (MIPs) by the liquid chromatography (LC) suggested that MIPs had selective separation ability for certain HO-PCB analogues. The results of the LC evaluations and molecular modeling indicated that the molecular volumes and pK_a values of template molecules were related with the retention factor of HO-PCBs. Additionally, according to the detail evaluation toward the selective separation behaviors of MIPs, these HO-PCB analogues have low pK_a values dependent on their chemical structures. In other words, the prepared MIPs had selective recognition ability against the analogues, which have an OH group on a phenyl carbon and two chlorine atoms on the both neighboring carbons of the carbon attached with the OH group. Moreover, these analogues may have a potential for thyroid hormone activities so that we attempted to separate these analogues directly from mixtures of HO-PCBs using a prepared MIP.     

Dramatic structural rearrangements in porous coordination networks

With the use of ab initio X-ray powder diffraction, a family of isostructural crystalline porous coordination networks, [(ZnX(2))(3)(TPT)(2)](n)· (solvent) (X = I, Br, Cl), has been studied at elevated temperatures of 573-723 K. Upon heating, all three networks exhibited crystalline-to-amorphous-to-crystalline (CAC) phase transformations to three new networks, [(ZnI(2))(3)(TPT)(2)](n), [(ZnBr(2))(3)(TPT)(2)](n)·(H(2)O) and [(ZnBr(2))(μ-Br)(ZnBr)(TPT)](n), and [(ZnCl(2))(μ-Cl)(ZnCl)(TPT)](n), respectively. A set of control experiments was used to obtain detailed mechanistic aspects of the CAC transformations. We demonstrate how bonds are broken and formed in these significant molecular rearrangements and how the initial arrangement plays a crucial role in the formation of the new networks after the CAC transformations. The structural information in the amorphous phase is retained and passed from a metastable to a more stable crystal, thus, reinforcing the notion that coordination networks are flexible and chemically active.     

PIV measurement of particle motion in spiral gas–solid two-phase flow

With a concise review on some basic and novel algorithms and methods for the techniques of particle-imaging velocimetry (PIV), the paper reports an application of the PIV techniques to the investigation of particle motion in a gas–solid two-phase spiral flow in a horizontal tube. Axial velocities of the transported particles are obtained. Some important features of particle motion governing high transportation efficiency of the spiral flow are revealed by investigating probability density distribution of particle locations in a pipe cross-section.     

Resistively coupled single-electron transistor using tunnel gate resistor

A resistively coupled single-electron transistor (R-SET) was fabricated using a modulation-doped heterostructure and metal Schottky gates, and measured at low temperature. Currents of R-SET with tunnel gate resistor were calculated using the orthodox theory. It is shown that the R-SET with tunnel gate resistor has quite similar properties to the originally proposed R-SET.     

Analytical and Numerical Study on Thermally Developing Forced Convective Flow in a Channel Filled with a Highly Porous Medium Under Local Thermal Non-Equilibrium

Transport in Porous Media - An analytical and numerical study was made on thermally developing forced convective flow in a channel filled with a fluid-saturated porous medium, subject to constant...