In situ SR-XPS observation of Ni-assisted low-temperature formation of epitaxial graphene on 3C-SiC/Si

Low-temperature (~1073 K) formation of graphene was performed on Si substrates by using an ultrathin (2 nm) N

In Situ SR-XPS Observation of Ni-Assisted Low-Temperature Formation of Epitaxial Graphene on 3C-SiC/Si

Low-temperature (~1073 K) formation of graphene was performed on Si substrates by using an ultrathin (2 nm) Ni layer deposited on a 3C-SiC thin film heteroepitaxially grown on a Si substrate. Angle-resolved, synchrotron-radiation X-ray photoemission spectroscopy (SR-XPS) results show that the stacking order is, from the surface to the bulk, Ni carbides(Ni(3)C/NiC(x))/graphene/Ni/Ni silicides (Ni(2)Si/NiSi)/3C-SiC/Si. In situ SR-XPS during the graphitization annealing clarified that graphene is formed during the cooling stage. We conclude that Ni silicide and Ni carbide formation play an essential role in the formation of graphene

In situ SR-XPS observation of Ni-assisted low-temperature formation of epitaxial graphene on 3C-SiC/Si

Low-temperature (~1073 K) formation of graphene was performed on Si substrates by using an ultrathin (2 nm) N

Insights into the Proton Transfer Mechanism of a Bilin Reductase PcyA Following Neutron Crystallography

Phycocyanobilin, a light-harvesting and photoreceptor pigment in higher plants, algae, and cyanobacteria, is synthesized from biliverdin IXα (BV) by phycocyanobilin:ferredoxin oxidoreductase (PcyA) via two steps of two-proton-coupled two-electron reduction. We determined the neutron structure of PcyA from cyanobacteria complexed with BV, revealing the exact location of the hydrogen atoms involved in catalysis. Notably, approximately half of the BV bound to PcyA was BVH⁺, a state in which all four pyrrole nitrogen atoms were protonated. The protonation states of BV complemented the protonation of adjacent Asp105. The “axial” water molecule that interacts with the neutral pyrrole nitrogen of the A-ring was identified. His88 Nδ was protonated to form a hydrogen bond with the lactam O atom of the BV A-ring. His88 and His74 were linked by hydrogen bonds via H₃O⁺. These results imply that Asp105, His88, and the axial water molecule contribute to proton transfer during PcyA catalysis

Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program

International audienceThis paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg|$^2$| in all five broad-band filters (⁠|$grizy$|⁠) to the nominal survey exposure (10 min in |$gr$| and 20 min in |$izy$|⁠). Partially observed areas are also included in the release; about 1100 deg|$^2$| is observed in at least one filter and one exposure. The median seeing in the i-band is |${0_{.}^{\prime \prime }6}$|⁠, demonstrating the superb image quality of the survey. The Deep (26 deg|$^2$|⁠) and UltraDeep (4 deg|$^2$|⁠) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of |$i\sim 28$| at |$5 \, \sigma$| for point sources. In addition to the broad-band data, narrow-band data are also available in the Deep and UltraDeep fields. This release includes a major update to the processing pipeline, including improved sky subtraction, PSF modeling, object detection, and artifact rejection. The overall data quality has been improved, but this release is not without problems; there is a persistent deblender problem as well as new issues with masks around bright stars. The user is encouraged to review the issue list before utilizing the data for scientific explorations. All the image products as well as catalog products are available for download. The catalogs are also loaded into a database, which provides an easy interface for users to retrieve data for objects of interest. In addition to these main data products, detailed galaxy shape measurements withheld from Public Data Release 1 (PDR1) are now available to the community. The shape catalog is drawn from the S16A internal release, which has a larger area than PDR1 (160 deg|$^2$|⁠). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/