Search

The molecular orientational randomization dynamics of organic thin films during annealing were measured by real-time in situ ellipsometry. The spirofluorene derivatives used in this work formed amorphous thin films with the molecules oriented parallel to the substrates when the films were vacuum deposited at room temperature. However, the molecular orientations became random when the thin films were annealed at temperatures higher than the glass transition temperature because molecular migration occurred. Analysis of the ellipsometry results using a graded model showed that the randomization of the molecular orientations depended on the thickness of the thin film. This suggests that the surface glass transition temperatures are lower than the bulk glass transition temperatures in the thin films of these small molecules.

The dynamics of liposome solubilization was monitored by dynamic light scattering and optical microscopy. A newly designed Y-shape microchannel connected to a room was incorporated into a microchip and the reaction processes of the liposome suspension and surfactant solution were observed in the room after mixing the two fluids and stopping the flow. By using this microchip, we succeeded in real-time monitoring of liposome solubilization and the following dynamic processes of solubilization were proposed: 1) Deformed liposomes become spherical. 2) The liposome size increases until the surfactant/liposome ratio in the liposome membrane reaches a threshold value. 3) Mixed micelles of surfactants and phospholipids are released and the liposomes collapse.

The dependence of the amplified spontaneous emission threshold (Eth) on molecular orientation in vacuum deposited thin films fabricated from diphenyldiamine- and carbazole-substituted spirofluorene derivatives was investigated. The molecular orientations were modified by changing the substrate temperature during deposition and were almost parallel to the substrate at around 300 K in all of the films. The orientation became random in the film containing diphenyldiamine compound at around 380 K, resulting in decreased optical anisotropy. However, for the carbazole compound, the molecular orientation scarcely changed from 300 to 380 K, while the root-mean-square roughness increased from 0.28 to 0.94 nm. Ethapproximately doubled for both the films when the optical anisotropy decreased because of the randomization of molecular orientation or when the surface roughness increased.

A new type of dynamic light scattering method for the size measurement of nanoparticles was developed using a transmission grating. A sample cell was located behind the grating, and light was incident from the grating side. The scattered light by a solution with nanopariticles was mixed with diffracted light by the grating, and the mixed signal was detected; namely, the diffracted light was used as reference light for heterodyne detection. It was confirmed that the S/Nratio of the autocorrelation curve was 26-times improved by heterodyne detection. Furthermore, the S/Nratio was improved by setting the sample cell at the sample grating distance where the electromagnetic field is maximum due to the Talbot effect. Size measurements for several kinds of nanoparticles were demonstrated by this new method.

We demonstrate two efficient blue-green thermally activated delayed fluorescence (TADF) compounds comprising a dimeric phenylcarbazole and four cyano substituents on the phenyl rings. A comparison of the 2,6-dicyano-substituted derivative (26IPNDCz) with the 3,5-dicyano-substituted derivative (35IPNDCz) shows that 26IPNDCz provides a larger dihedral angle and a lower decrease in the energy difference between the first singlet and triplet excited states (ΔEST) and the TADF lifetime. An organic light-emitting diode based on 26IPNDCz afforded an external quantum efficiency of 10% with reduced efficiency roll-off.

A nonhemolytic strain of Staphylococcus aureuswas transformed with deoxyribonucleic acid extracted from two hemolytic strains of S. aureus. In each case the hemolysin pattern after transformation was identical to that of the donor strain. However, bacteriophage type, serotypes, and other biological properties of the recipient strain remained unaffected.

We reported previously that β-blocking agents produced a sustained pressor action in anesthetized rats, and this pressor action was probably due to the blockade of the β-adrenoceptors mediating vasodilation in the vascular bed of skeletal muscle. In this study, experiments using rat hindquarters were performed to investigate further the mechanism of the pressor action. The effects of propranolol, Carteolol, practolol and acebutolol administered intraarterially to the hindquarters were studied. These β-blocking agents produced a sustained rise in perfusion pressure. The pressor actions of practolol and acebutolol were greater tnan we expected. Also effects of these β-blocking agents on changes in perfusion pressure produced by isoproterenol in rat hindquarters were studied. Inhibitory actions of practolol and acebutolol on the isoproterenol-induced depressor action in rat hindquarters were greater than in intact rats. From tnese results, it is considered that practolol and acebutolol may be able to block to a conciderable extent, not only β2-receptors in the heart, but also β2-receptors in the peripheral vascular beds in rats.