Abstract: [Object] Provided are a 11C-labeled acyclic retinoid that can be synthesized in a short time with a high yield and can be suitably used for PET for elucidating intracerebral kinetics, a PET probe using it, and methods for producing them. [Solution] The 11C-labeled acyclic retinoid of the present invention is characterized by being represented by the following chemical formula (a). This compound can be produced by a coupling step of cross-coupling a methyl iodide labelled with 11C and the following organotin compound (b) (provided that in the formula, R1 and R2 represent alkyl groups which may have a branch) in an aprotic solvent in the presence of a palladium complex, a phosphine ligand, and a cuprous halide.

Abstract: Disclosed is a synthetic medium with PDGF, vitronectin, IL-1.beta. and BSA added to Eagle's minimum essential medium or medium with transferrin, insulin, progesterone and putrescine further added thereto. When cultivating the postnatal central neurons using the inventive medium, there are effects such that good attachment to substrate, extension of neuritic processes and maintenance of survival are achieved, that more stable sure cultivation becomes possible as well over the astrocyte-conditioned medium used hitherto, and the like.

Abstract: A resin composition for soft bumpers is disclosed, comprising (a) 100 parts by weight of a selectively hydrogenated block copolymer having at least two mono-alkenyl or mono-alkenylidene aromatic hydrocarbon polymer blocks having a number average molecular weight of from 5,000 to 15,000 and at least one partially or completely hydrogenated aliphatic conjugated diene hydrocarbon polymer block having a number average molecular weight of from 10,000 to 75,000, (b) from 10 to 100 parts by weight of an ethylene-propylene copolymer rubber having a Mooney viscosity of from 15 to 50 as measured at 100.degree. C. and an intrinsic viscosity of from 1.2 to 2.0 dl/g as measured in a xylene solution at 70.degree. C., (c) from 200 to 400 parts by weight of a propylene-ethylene block copolymer having a melt flow rate of from 10 to 30 g/10 min and an ethylene content of from 5 to 15% by weight, and (d) from 20 to 200 parts by weight of a non-aromatic diluent oil for rubber.