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.

Aqueous electrochemistry of poly(vinylanthraquinone) for anode-active materials in high-density and rechargeable polymer/air batteries.

Abstract: A layer of poly(2-vinylanthraquinone) on current collectors underwent reversible electrode reaction at -0.82 V vs Ag/AgCl in an aqueous electrolyte. A repeatable charging/discharging cycles with a redox capacity comparable to the formula weight-based theoretical density at the negative potential suggested that all of the anthraquinone pendants in the layer was redox-active, that electroneutralization by an electrolyte cation was accomplished throughout the polymer layer, and that the layer stayed on the current collector without exfoliation or dissolution into the electrolyte during the electrolysis. The charging/discharging behavior of the polymer layer in the aqueous electrolyte revealed the capability of undergoing electrochemistry even in the nonsolvent of the pendant group, which offered insight into the nature of the anthraquinone pendants populated on the aliphatic chain. Charging/discharging capability of air batteries was accomplished by using the polymer layer as an organic anode-active material. A test cell fabricated using the conventional MnO(2)/C cathode catalyst exhibited a discharging voltage at 0.63 V corresponding to their potential gap and a charging/discharging cycle of more than 500 cycles without loss of the capacity.

Discovery and evolutionary history of gonadotrophin-inhibitory hormone and kisspeptin: new key neuropeptides controlling reproduction.

Abstract: Gonadotrophin-releasing hormone (GnRH) is the primary hypothalamic factor responsible for the control of gonadotrophin secretion in vertebrates. However, within the last decade, two other hypothalamic neuropeptides have been found to play key roles in the control of reproductive functions: gonadotrophin-inhibitory hormone (GnIH) and kisspeptin. In 2000, we discovered GnIH in the quail hypothalamus. GnIH inhibits gonadotrophin synthesis and release in birds through actions on GnRH neurones and gonadotrophs, mediated via GPR147. Subsequently, GnIH orthologues were identified in other vertebrate species from fish to humans. As in birds, mammalian and fish GnIH orthologues inhibit gonadotrophin release, indicating a conserved role for this neuropeptide in the control of the hypothalamic-pituitary-gonadal axis across species. Subsequent to the discovery of GnIH, kisspeptin, encoded by the KiSS-1 gene, was discovered in mammals. By contrast to GnIH, kisspeptin has a direct stimulatory effect on GnRH neurones via GPR54. GPR54 is also expressed in pituitary cells, but whether gonadotrophs are targets for kisspeptin remains unresolved. The KiSS-1 gene is also highly conserved and has been identified in mammals, amphibians and fish. We have recently found a second isoform of KiSS-1, designated KiSS-2, in several vertebrates, but not birds, rodents or primates. In this review, we highlight the discovery, mechanisms of action, and functional significance of these two chief regulators of the reproductive axis.

Ir(I)-catalyzed C-H bond alkylation of C2-position of indole with alkenes: selective synthesis of linear or branched 2-alkylindoles.

Abstract: A cationic iridium-catalyzed C2-alkylation of N-substituted indole derivatives with various alkenes has been developed, which selectively gives linear or branched 2-alkylindoles in high to excellent selectivity. This protocol relies on the use of the carbonyl group on the nitrogen atom of indole as a directing group: a linear product was predominant when an acetyl group was used as a directing group, and a branched product was predominant with a benzoyl group.

Searches for Higgs boson pair production in the hh →bbττ, γγWW∗, γγbb, bbbb channels with the ATLAS detector

Abstract: Searches for both resonant and nonresonant Higgs boson pair production are performed in the hh -> bb tau tau, gamma gamma WW* final states using 20.3 fb(-1) of pp collision data at a center-of-m ...

Transmission Analysis of OFDM-Based Wireless Services Over Turbulent Radio-on-FSO Links Modeled by Gamma–Gamma Distribution

Abstract: Radio-on-free space optical (RoFSO) communication systems are rapidly gaining popularity as an efficient and cost-effective means of transferring high data rates and radio frequency (RF) signals with the same capacity as optical fiber. However, the performance of those systems depends strongly on the atmospheric conditions and the nonlinear characteristics of the optical link. In this paper, we introduce an analytical model for the transmission of orthogonal frequency division multiplexing (OFDM)-based signals over freespace optics (FSO) links. Further, we derive a closed-form bit error probability (BEP) and outage probability expressions, taking into account the optical noises, the laser diode nonlinear distortion, and the atmospheric turbulence effect on the FSO channel modeled by the gamma-gamma distribution. This paper reports the most significant parameters that degrade the transmission performance of the OFDM signal over FSO links and indicates the cases that provide the optimal operating conditions for the link. The obtained results can be useful for designing, predicting, and evaluating the RoFSO system's ability to transmit wireless services over turbulent FSO links under actual conditions.