Waseda University

About: Waseda University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Catalysis & Large Hadron Collider. The organization has 24220 authors who have published 46859 publications receiving 837855 citations. The organization is also known as: Waseda daigaku & Sōdai.

Strategic Synthesis of Trimetallic Au@Pd@Pt Core−Shell Nanoparticles from Poly(vinylpyrrolidone)-Based Aqueous Solution toward Highly Active Electrocatalysts

Abstract: Our recent study has shown that Pluronic F127 triblock copolymer can assist the formation of unique Au@Pd@Pt triple-layered core−shell-structured nanoparticles consisting of a Au core, a Pd inner layer, and nanoporous Pt outer shell (J. Am. Chem. Soc.2010, 132, 13636). Pluronic F127 is a very typical surfactant that is commonly used in the synthesis of mesoporous silica and carbon, but Pluronic F127 is very rarely used for the synthesis of metallic nanostructures. Herein, we expand our previous concept to further demonstrate that such interesting Au@Pd@Pt nanoparticles can be easily synthesized by using poly(vinylpyrrolidone) (PVP) instead of Pluronic F127. PVP is a very typical capping and structure-directing agent used for the synthesis of various metallic nanostructures. The present synthetic route using a PVP-based aqueous solution will greatly contribute to the further design of multilayered metallic nanoarchitectures with designed compositions and desired functions. Furthermore, a detailed investiga...

Anisotropy and corotation of galactic cosmic rays.

Abstract: The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

Identification, Expression, and Physiological Functions of Siberian Hamster Gonadotropin-Inhibitory Hormone

Abstract: Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion in birds and mammals. To further understand its physiological roles in mammalian reproduction, we identified its precursor cDNA and endogenous mature peptides in the Siberian hamster brain. The Siberian hamster GnIH precursor cDNA encoded two RFamide-related peptide (RFRP) sequences. SPAPANKVPHSAANLPLRF-NH(2) (Siberian hamster RFRP-1) and TLSRVPSLPQRF-NH(2) (Siberian hamster RFRP-3) were confirmed as mature endogenous peptides by mass spectrometry from brain samples purified by immunoaffinity chromatography. GnIH mRNA expression was higher in long days (LD) compared with short days (SD). GnIH mRNA was also highly expressed in SD plus pinealectomized animals, whereas expression was suppressed by melatonin, a nocturnal pineal hormone, administration. GnIH-immunoreactive (-ir) neurons were localized to the dorsomedial region of the hypothalamus, and GnIH-ir fibers projected to hypothalamic and limbic structures. The density of GnIH-ir perikarya and fibers were higher in LD and SD plus pinealectomized hamsters than in LD plus melatonin or SD animals. The percentage of GnRH neurons receiving close appositions from GnIH-ir fiber terminals was also higher in LD than SD, and GnIH receptor was expressed in GnRH-ir neurons. Finally, central administration of hamster RFRP-1 or RFRP-3 inhibited LH release 5 and 30 min after administration in LD. In sharp contrast, both peptides stimulated LH release 30 min after administration in SD. These results suggest that GnIH peptides fine tune LH levels via its receptor expressed in GnRH-ir neurons in an opposing fashion across the seasons in Siberian hamsters.