A new phlorotannin, named eckstolonol (1), was isolated from the EtOAc soluble fraction of the methanolic extract of the brown alga, Ecklonia stolonifera OKAMURA, along with three known phlorotannins, eckol (2), phlorofucofuroeckol A (3), and dieckol (4). The structure of eckstolonol was identified as 5,8,13,14-tetraoxa-pentaphene-1,3,6,9,11-pentaol on the basis of spectroscopic evidence. The new compound was found to be a radical scavenger on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. 相似文献
The thermal disruption of collagen I in rat tail tendon is investigated with second-harmonic generation (SHG) microscopy. We investigate its effects on SHG images and intensity in the temperature range 25 degrees-60 degrees C. We find that the SHG signal decreases rapidly starting at 45 degrees C. However, SHG imaging reveals that breakage of collagen fibers is not evident until 57 degrees C and worsens with increasing temperature. At 57 degrees C, structures of both molten and fibrous collagen exist, and the disruption of collagen appears to be complete at 60 degrees C. Our results suggest that, in addition to intensity measurement, SHG imaging is necessary for monitoring details of thermally induced changes in collagen structures in biomedical applications. 相似文献
Summary: In order to achieve a reasonable response time in an electrochromic display, viologen‐modified porous polymeric microspheres of various porosities have been used as substrates. Porous microspheres are prepared using seeded polymerization in the presence of a porogen. Based on ionic conductivity and the chronocoulometry measurements, it is confirmed that the electrolyte content increases, and the resistance of the polymer particles in the device decreases as the specific surface area of the porous particles increases. This results in a rapid response time of 270 ms.
Schematic representation of the viologen‐modified porous polymeric microspheres in the manufactured ECD device (A). Images of the device (B) in the OFF state (left) and in the ON state (right). 相似文献
Journal of Sol-Gel Science and Technology - Solution-processed oxide thin films have many attractive features for various electronic applications as like a next generation display and flexible... 相似文献
Herein, PEGylated multi-walled carbon nanotube (MWNT) was prepared for the successive fabrication of poly(vinyl alcohol) PVA/MWNT nanocomposite film by solution casting. The surface modified MWNT showed a good colloidal stability in a polar solvent, i.e., water. Also, the PEGylated MWNT had an improved dispersion stability in aqueous PVA solution. The mixture of PEGylated MWNT and PVA dissolved in water was film casted and the dispersion uniformity and corresponding improvement of electrical conductivity were investigated. The electrical conductivity of PVA/modified MWNT composite film was three-fold higher than that of PVA/pristine MWNT composite film due to the much improved distribution uniformity of modified MWNT in PVA matrix. 相似文献
Adsorption and desorption of fullerene on a single layer of graphene grown on SiC(0001) were investigated by photoemission spectroscopy (PES). No significant change in the band structure of graphene was observed after fullerene deposition on the graphene layer under vacuum conditions, and subsequent exposure to the air. After annealing the fullerene layer at 275 °C in a vacuum, complete desorption of fullerene was observed without any resulting damage to the graphene structure. The desorption temperature of fullerene was significantly higher than that of pentacene, indicating that fullerene layers show higher stability than pentacene as protection layers of graphene-based devices. 相似文献
Solubility measurements over the pH range 2.6–7.6 for tetracycline, chlortetracycline, dimethylchlortetracycline and oxytetracycline are used to determine thermodynamic values for the solubility constant and the first and second acidity constants of these compounds. 相似文献