Osaka University

About: Osaka University is a education organization based out in Osaka, Japan. It is known for research contribution in the topics: Laser & Catalysis. The organization has 83778 authors who have published 185669 publications receiving 5158122 citations. The organization is also known as: Ōsaka daigaku.

Plasmonics for near-field nano-imaging and superlensing

Abstract: Diffraction of light prevents optical microscopes from having spatial resolution beyond a value comparable to the wavelength of the probing light. This essentially means that visible light cannot image nanomaterials. Here we review the mechanism for going beyond this diffraction limit and discuss how manipulation of light by means of surface plasmons propagating along the metal surface can help to achieve this. The interesting behaviour of light under the influence of plasmons not only allows superlensing, in which perfect imaging is possible through a flat thin metal film, but can also provide nano-imaging of practical samples by using a localized surface plasmon mode at the tip of a metallic nanoprobe. We also discuss the current research status and some intriguing future possibilities.

5-Hydroxymethylcytosine in the mammalian zygote is linked with epigenetic reprogramming

Abstract: The epigenomes of early mammalian embryos are extensively reprogrammed to acquire a totipotent developmental potential. A major initial event in this reprogramming is the active loss/demethylation of 5-methylcytosine (5mC) in the zygote. Here, we report on findings that link this active demethylation to molecular mechanisms. We detect 5-hydroxymethylcytosine (5hmC) as a novel modification in mouse, bovine and rabbit zygotes. On zygotic development 5hmC accumulates in the paternal pronucleus along with a reduction of 5mC. A knockdown of the 5hmC generating dioxygenase Tet3 simultaneously affects the patterns of 5hmC and 5mC in the paternal pronucleus. This finding links the loss of 5mC to its conversion into 5hmC. The maternal pronucleus seems to be largely protected against this mechanism by PGC7/Dppa3/Stella, as in PGC7 knockout zygotes 5mC also becomes accessible to oxidation into 5hmC. In summary, our data suggest an important role of 5hmC and Tet3 for DNA methylation reprogramming processes in the mammalian zygote.

Spin-triplet superconductivity in Sr2RuO4 identified by 17O knight shift

Abstract: Superconductivity — one of the best understood many-body problems in physics — has again become a challenge following the discovery of unconventional superconducting materials: these include heavy-fermion1, organic2 and the high-transition-temperature copper oxide3 superconductors In conventional superconductors, the electrons form superconducting Cooper pairs in a spin-singlet state, which has zero total spin (S = 0) In principle, Cooper pairs can also form in a spin-triplet state (S = 1), analogous to the spin-triplet ‘p-wave’ state of paired neutral fermions in superfluid 3He (ref 4) At present, the heavy-fermion compound UPt3 is the only known spin-triplet superconductor5,6, although the layered oxide superconductor Sr2RuO4 (ref 7) is believed, on theoretical grounds8, to be a promising candidate The most direct means of identifying the spin state of Cooper pairs is from measurements of their spin susceptibility, which can be determined by the Knight shift (as probed by nuclear magnetic resonance (NMR)) Here we report Knight-shift measurements of Sr2RuO2 using 17O NMR Our results show no change in spin susceptibility on passing through the superconducting transition temperature, which provides the definitive identification of Sr2RuO4 as a spin-triplet superconductor