Publications by authors named "Susumu Nagayama"

This study proposes the notion of "root concepts" in cultural production, defined as a novel style and mode that a creator expresses at the initial field development phase, and that has a great influence on subsequent creators. We explore the role of root concepts in cultural evolution by focusing on their capacity to generate new combinations with other elements and examine how creators use root concepts jointly with other elements. Using data on artists and albums in the rap genre from the online database Allmusic, we view music moods as a type of experience that music generates and focus on music moods as a phenotype in studying styles and modes.

View Article and Find Full Text PDF

The relationship between the time-dependent change in serum proteins adsorbed on nanoparticles and their disposition to the liver was investigated by employing lecithin-coated polystyrene nanosphere with a size of 50 nm (LNS-50) as a model nanoparticle in rats. The total amount of proteins adsorbed on LNS-50 increased and the qualitative profile of serum proteins adsorbed on LNS-50 changed during the incubation with serum up to 360 min. The liver perfusion study indicated that the hepatic uptake of LNS-50 incubated with serum for 360 min was significantly larger than those of LNS-50 incubated for shorter period.

View Article and Find Full Text PDF

We tried to evaluate the possible involvement of fetuin in the scavenger receptors (SRs)-mediated hepatic uptake of polystyrene nanospheres with the size of 50 nm (NS-50), which has surface negative charge (zeta potential=-21.8+/-2.3 mV).

View Article and Find Full Text PDF

We evaluated the in vivo disposition characteristics of polystyrene nanospheres (NS) with the particle size of 50 nm (NS-50) pre-coated with human serum albumin (HSA) after intravenous administration in rats. HSA-coated NS-50 showed much longer blood-circulating property and the hepatic uptake clearance for HSA-coated NS-50 was about 1/5 of that for NS-50. In parallel with the results obtained in the in vivo study, liver perfusion experiments also showed that the hepatic disposition of HSA-coated NS-50 was much less than that of NS-50 in the presence of serum in the perfusate.

View Article and Find Full Text PDF

The mechanisms involved in the hepatic uptake of negatively charged carboxylated-polystyrene nanospheres with a size of 50 nm (CNS-50) were examined in rats. The liver perfusion experiments revealed that hepatic disposition of CNS-50 in the absence of serum could be partially ascribed to the direct recognition of the surface negative charge by scavenger receptors. On the other hand, the apparent negative charge of CNS-50 surface dramatically reduced in the presence of serum, because the adsorption of serum protein on their surface results in masking their intrinsic negative charge.

View Article and Find Full Text PDF

To elucidate the important factors for the difference in the hepatic disposition between polystyrene nanospheres with a size of 50 nm (NS-50) and lecithin-coated NS-50 (LNS-50), the liver perfusion studies and the in vitro uptake studies using the cultured Kupffer cells were performed. It was suggested that opsonin-mediated phagocytosis is not significantly involved in the hepatic disposition of LNS-50 in the presence of serum, whereas its involvement in the hepatic uptake of NS-50 was clearly demonstrated. Western blot analysis showed that IgG, complement C3, and fibronectin, well-known opsonins in the serum, adsorbed on the surface of NS-50 in larger amount than on the surface of LNS-50.

View Article and Find Full Text PDF