Waseda University

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

Gender differences in the viscoelastic properties of tendon structures

Abstract: The purpose of this study was to investigate the differences in the viscoelastic properties of human tendon structures (tendon and aponeurosis) in the medial gastrocnemius muscle between men (n=16) and women (n=13). The elongation of the tendon and aponeurosis of the medial gastrocnemius muscle was measured directly by ultrasonography, while the subjects performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between the estimated muscle force (Fm) and tendon elongation (L) during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness. The percentage of the area within the Fm- L loop to the area beneath the curve during the ascending phase was calculated as hysteresis. The L values at force production levels beyond 50 N were significantly greater for women than for men. The maximum strain (100xDeltaL/initial tendon length) was significantly greater in women [9.5 (1.1)%] than in men [8.1 (1.6)%]. The stiffness and Young's modulus were significantly lower in women [16.5 (3.4) N/mm, 277 (25) MPa] than in men [25.9 (7.0) N/mm, 356 (32) MPa]. Furthermore, the hysteresis was significantly lower in women [11.1 (5.9)%] than in men [18.7 (8.5)%, P=0.048]. These results suggest that there are gender differences in the viscoelastic properties of tendon structures and that these might in part account for previously observed performance differences between the genders.

Assembly of Hollow Carbon Nanospheres on Graphene Nanosheets and Creation of Iron–Nitrogen-Doped Porous Carbon for Oxygen Reduction

Abstract: Triblock copolymer micelles coated with melamine-formaldehyde resin were self-assembled into closely packed two-dimensional (2D) arrangements on the surface of graphene oxide sheets. Carbonizing these structures created a 2D architecture composed of reduced graphene oxide (rGO) sandwiched between two monolayers of sub-40 nm diameter hollow nitrogen-doped carbon nanospheres (N-HCNS). Electrochemical tests showed that these hybrid structures had better performance for oxygen reduction compared to physically mixed rGO and N-HCNS that were not chemically bonded together. Further impregnation of the sandwich structures with iron (Fe) species followed by carbonization yielded Fe1.6-N-HCNS/rGO-900 with a high specific surface area (968.3 m2 g–1), a high nitrogen doping (6.5 at%), and uniformly distributed Fe dopant (1.6 wt %). X-ray absorption fine structure analyses showed that most of the Fe in the nitrogen-doped carbon framework is composed of single Fe atoms each coordinated to four N atoms. The best Fe1.6-N...

Correlation of the 5.0- and 7.6-eV absorption bands in SiO2 with oxygen vacancy

Abstract: Various uv and vacuum-uv optical-absorption bands found in as-manufactured high-purity ${\mathrm{SiO}}_{2}$ glass were studied. Two types of absorption bands were found near 5.0 eV, one of which is attributed to the oxygen vacancy (?Si-Si?). The absorption band at 7.6 eV is also found to be caused by the same oxygen vacancy. Observation of the decay lifetime of photoluminescence and calculations using the ab initio molecular-orbital program show that the 7.6-eV band is caused by a singlet-to-singlet transition, while the 5.0-eV band is caused by a singlet-to-triplet transition.

Gene fliA encodes an alternative sigma factor specific for flagellar operons in Salmonella typhimurium

Abstract: Through genetic studies, the fliA gene product has been shown to regulate positively gene expression in late operons of the flagellar regulon in Salmonella typhimurium. In the present study, the fliA gene was cloned and sequenced. The fliA coding region consisted of 717 nucleotides beginning with the GTG initiation codon and the conserved sequence specific to promoters for flagellar operons was found to exist upstream of the coding region. The fliA gene product deduced from the nucleotide sequence was a protein with 239 amino acid residues and the calculated molecular mass was 27,470 dalton. The deduced amino acid sequence was homologous with that of sigma 28, a flagellar specific sigma factor of Bacillus subtilis. The fliA gene product was identified as a protein of molecular mass 29 kDa in the in vitro transcription-translation system, while three proteins of 29 kDa, 31 kDa and 32 kDa were found in the products programmed by the fliA gene in minicells and in maxicells. The 29 kDa FliA protein was purified from the FliA overproducing strain which carried the ptac-fliA fusion. This protein activated the in vitro synthesis of flagellin, the fliC gene product. RNA polymerase containing the purified FliA protein was shown to transcribe the fliC gene. These results indicate that FliA protein functions as an alternative sigma factor specific for S. typhimurium flagellar operons.