Formation and Characterization of Reversed Micelles Composed of Phospholipids and Fatty Acids

The formation of reversed micellar systems composed of phosphatidylcholine (PC) and fatty acid was newly demonstrated by a significant increase in water content in the organic ethyl oleate phase when the micelles were prepared by the contact method. The solubilized water concentration in the reversed micellar organic phase reached 3 wt%. The new systems are expected to be used as highly biocompatible reversed micellar systems. The structure of the reversed micelles composed of PC and oleic acid was characterized by determining the water concentration and by small-angle X-ray scattering analysis. The reversed micelles composed of PC and oleic acid formed in ethyl oleate were spherical. The radius of gyration was between 30 and 50 Å. The size of the reversed micelles decreased with an increase in the oleic acid concentration and was independent of the PC concentration. Experimental results indicated that the structure of the reversed micellar system was determined by the oleic acid concentration. An increase in the PC concentration caused an increase in the number of reversed micelles of the same size. These reversed micellar systems are expected to be used as solubilization media in pharmaceutical and food industries because they are not toxic.     

Post-deposition atomic terraces growth of ZnO thin films deposited on epi-GaN templates

We demonstrate how growth processes affect on ZnO film properties, which are to be essential guides to prevent defect formation in order to synthesize reproducible high quality ZnO films. First, we reveal that deposition at a low temperature is indispensable to transfer underlying GaN atomic terraces to ZnO surface. As the film thickness is increased, however, the terraces disappear to develop island morphology. It is found that the thick film surface is smoothed to the extent that atomic terraces can be seen after an appropriate thermal treatment. Adverse effects associated with high annealing temperatures are then demonstrated as evidenced by cracks formation, increased yellow cathode-luminescence and intermixing at the interface.     

First-principles molecular dynamics simulation of biased electrode/solution interface

First-principles molecular dynamics simulations have been carried out for water in contact with Pt(1 1 1) surface. To apply negative bias potential to the water/Pt interface, excess electrons were added to our slab model using the recently developed computational scheme called “effective screening medium (ESM)”. Water molecules located away from the surface reoriented themselves to screen the electric field, but they responded differently near the surface. Water molecules nearest to the surface, forming a distinct layered structure with the hydrogen atom directed to the surface, increased the density with increasing field. On these bases, we discuss microscopic aspects of the electric double layer.     

Unique thermal behavior of acrylic PSAs bearing long alkyl side groups and crosslinked by aluminum chelate

An acrylic pressure-sensitive adhesive (PSA), bearing octadecyl acrylate, methyl acrylate and acrylic acid groups, and crosslinked by aluminum acetylacetonate (AlACA), displayed behavior unique among acrylic PSAs in that its adhesion, which decreases with an increase in temperature, began to increase again from around 150 °C. In order to understand this behavior, the structure and thermal properties of the PSA were investigated in detail, along with another PSA crosslinked by a covalent crosslinking agent (Az). From thermal mechanical analysis, the PSA with ionic crosslinks (AlACA) showed three softening points at 20, 60, and 160 °C. In comparison, the PSA covalently crosslinked by Az only exhibited two softening points (at 20 and 60 °C). The softening point at 160 °C is clearly related to ionic chelate crosslinking. DSC measurements indicated that the softening point at 20 °C resulted from melting of the ordered octadecyl group, and the softening point at 60 °C was due to an increase in the mobility of the main chain. The temperature dependence of viscoelastic measurements revealed that the viscosity of the PSA crosslinked by AlACA increased at around 160 °C. From these results, we considered that the distinctive adhesion of the PSA crosslinked by AlACA could be due to ligand exchange at the aluminum crosslinking points, which are chelated by carboxy groups built in the main chain.     

Nuclear Reactions and Radionuclides in the Study of Fullerenes

Radiochemical techniques have been applied in various ways to the study of fullerenes and metallofullerenes for the past several years, and they have provided invaluable information pertaining to the stability, structures, and formation of the novel carbon material. This paper reviews those experimental results that have fully shown the usefulness and uniqueness of radionuclides demonstrated in the field of fullerene science.     

Synthesis and domino metathesis of functionalized 7-oxanorbornene analogs toward cis-fused heterocycles

Here, we report our strategy to synthesize structurally diverse cis-fused heterocycles via 7-oxanorbornene analogs. By the intramolecular Diels-Alder reaction of 3-iodoacrylamide, followed by the domino metathesis reaction, the cis-fused heterobicyclic skeleton was efficiently constructed in 5-8 steps.     

A modified technique of the self-absorption method applicable to natural mercury afterglows

A modified technique of the self-absorption method has been developed and applied to natural mercury afterglows. A narrow light-emitting layer is produced inside an absorption tube by external pumping at the moment of measuring the afterglow.