Search Results - (Author, Cooperation:J. H. Ryu)

2018-01-03

The Society of Nuclear Medicine (SNM)

0022-3123

Medicine

2011-11-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Acetobacter/genetics/*physiology ; Animals ; Body Size/genetics ; Carbohydrate Dehydrogenases/*metabolism ; Drosophila/growth & development/*microbiology ; Female ; Homeostasis ; Insulin/*metabolism ; Intestines/microbiology ; Metagenome/*physiology ; *Signal Transduction ; Somatomedins/metabolism

1615-6102

Chloroplasts ; Epidermal cell ; Microfilament ; Orientation movement ; Phytochrome ; Vallisneria gigantea Graebner

Springer Online Journal Archives 1860-2000

Biology

Summary Using time-lapse video microscopy, we performed a semiquantitative investigation of the movement of chloroplasts on the cytoplasmic layer that faces the outer periclinal wall (P side) of epidermal cells of leaves of the aquatic angiospermVallisneria gigantea Graebner. Under continuous irradiation with red light (650 nm, 0.41 W/m2), the movement of chloroplasts on the P side was transiently accelerated within 5 min. The increased movement began to decrease at around 20 min and fell below the original level after 40 to 60 min of irradiation with red light. The acceleration and deceleration of movement of chloroplasts on the P side seemed to lead directly to the increase and the subsequent decrease in the rate of migration of chloroplasts from the P side to the anticlinal layers of cytoplasm, which are responsible for the accumulation of chloroplasts on the P side, as we demonstrated previously. In the presence of inhibitors of photosynthesis, the accelerated movement of chloroplasts was maintained for as long as the chloroplasts were irradiated with red light. The rapid acceleration and deceleration of the movement of chloroplasts could be observed repeatedly with sequential irradiation with red and then far-red light (746 nm, 0.14 W/m2). Concomitantly with the loss of motility of chloroplasts on the P side, a dynamic change in the configuration of microfilaments, from a network to a honeycomb, occurred on the P side.

Electronic Resource

1435-1536

Key words Monodisperse micron-sized polystyrene particles ; Urethane acrylate ; Particle diameter ; Particle number density ; Polymerization rate

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract Monodisperse micron-sized polystyrene particles crosslinked using urethane acrylate were produced by dispersion polymerization in ethanol solution and the effect of the crosslinked network structure on the polymerization procedure was studied. The influences of the concentrations of the initiator and urethane acrylate on the particle diameter (D n), the particle number density (N p), and the polymerization rate (R p) were found to obey the approximate relationships D n ∝ [initiator]0.43 [urethane acrylate]0.05, N p ∝ [initiator]−1.30 [urethane acrylate]0.19, and R p ∝ [initiator]0.24 ± 0.02. The power-law dependence of D n and N p on the initiator concentration showed a similar trend to that of linear polystyrene reported in the literature. Especially, it was found that urethane acrylate does not have a serious effect on D n and N p of the particles produced. The dependence of R p on the initiator concentration was observed to be higher than that of linear polystyrene, suggesting that there is still competition between heterogeneous polymerization and solution polymerization because of the crosslinked network structure of the primary particle.

Electronic Resource