National Institute of Advanced Industrial Science and Technology

About: National Institute of Advanced Industrial Science and Technology is a government organization based out in Tsukuba, Ibaraki, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 22114 authors who have published 65856 publications receiving 1669827 citations. The organization is also known as: Sangyō Gijutsu Sōgō Kenkyū-sho.

Electron knock-on damage in hexagonal boron nitride monolayers

Abstract: We combine first-principles molecular-dynamics simulations with high-resolution transmission electron microscopy experiments to draw a detailed microscopic picture of irradiation effects in hexagonal boron nitride ($h$-BN) monolayers. We determine the displacement threshold energies for boron and nitrogen atoms in $h$-BN, which differ significantly from the tight-binding estimates found in the literature and remove ambiguity from the interpretation of the experimental results. We further develop a kinetic Monte Carlo model which allows to extend the simulations to macroscopic time scales and make a direct comparison between theory and experiments. Our results provide a comprehensive picture of the response of $h$-BN nanostructures to electron irradiation.

Formation of Anhydrous and Hydrous Skarn in Cu-Au Ore Deposits by Magmatic Fluids

Abstract: Most skarn ore deposits are characterized by two distinctly different alteration styles. An early prograde stage with anhydrous minerals, such as garnet and pyroxene, forms from relatively high-temperature, hypersaline liquid. A later retrograde stage with hydrous minerals, such as epidote, amphibole, and chlorite plus sulfide ore minerals, forms from lower temperature, lower salinity fluids. These two alteration stages commonly have been thought to reflect a dominance of magmatic and meteoric water, respectively, with relevance to the source of ore metals. We report data from two different skarn systems, one being part of the world’s largest Cu-Au resource. Stable isotope compositions of anhydrous and hydrous alteration minerals from both deposits indicate a magmatic source for both the prograde and retrograde stages: δ 18O averages 5.0 per mil for garnet (range, 3.4–7.2‰), 6.5 per mil for pyroxene (4.3–8.2‰), and 7.1 per mil for amphibole (4.3–8.7‰). The δ D values of late amphibole are more complex, with magmatic values (–77 to –78‰) for one deposit and both magmatic and lighter values for another deposit that could be explained either by magmatic degassing or by limited mixing with meteoric water. We conclude that the differences in fluid composition—prograde versus retrograde stages—resulted from a magmatic fluid that intersected its solvus during the early stage, creating vapor and hypersaline liquid, whereas in the later stage this magmatic fluid did not intersect its solvus because it followed a different cooling path. This late, low- salinity liquid only boiled once its vapor-pressure curve was reached, causing sulfide ore to precipitate during the retrograde stage.

Application of the MAFFT sequence alignment program to large data—reexamination of the usefulness of chained guide trees

Abstract: Motivation: Large multiple sequence alignments (MSAs), consisting of thousands of sequences, are becoming more and more common, due to advances in sequencing technologies. The MAFFT MSA program has several options for building large MSAs, but their performances have not been sufficiently assessed yet, because realistic benchmarking of large MSAs has been difficult. Recently, such assessments have been made possible through the HomFam and ContTest benchmark protein datasets. Along with the development of these datasets, an interesting theory was proposed: chained guide trees increase the accuracy of MSAs of structurally conserved regions. This theory challenges the basis of progressive alignment methods and needs to be examined by being compared with other known methods including computationally intensive ones. Results: We used HomFam, ContTest and OXFam (an extended version of OXBench) to evaluate several methods enabled in MAFFT: (1) a progressive method with approximate guide trees, (2) a progressive method with chained guide trees, (3) a combination of an iterative refinement method and a progressive method and (4) a less approximate progressive method that uses a rigorous guide tree and consistency score. Other programs, Clustal Omega and UPP, available for large MSAs, were also included into the comparison. The effect of method 2 (chained guide trees) was positive in ContTest but negative in HomFam and OXFam. Methods 3 and 4 increased the benchmark scores more consistently than method 2 for the three datasets, suggesting that they are safer to use. Availability and Implementation: http://mafft.cbrc.jp/alignment/software/ Contact: pj.ca.u-akaso.cerfi@hotak Supplementary information: Supplementary data are available at Bioinformatics online.

Systematic Alkaline Stability Study of Polymer Backbones for Anion Exchange Membrane Applications

Abstract: Anion exchange membranes are an important component in alkaline electrochemical energy conversion and storage devices, and their alkaline stability plays a crucial role for the long-term use of these devices. Herein, a systematic study was conducted for the analysis of polymer backbone chemical stability in alkaline media. Nine representative polymer structures including poly(arylene ether)s, poly(biphenyl alkylene)s, and polystyrene block copolymers were investigated for their alkaline stability. Polymers with aryl ether bonds in their repeating unit showed poor chemical stability when treated with KOH and NaOCH3 solutions, whereas polymers without aryl ether bonds [e.g., poly(biphenyl alkylene)s and polystyrene block copolymers] remained stable. Additional NMR studies and density functional theory (DFT) calculations of small molecule model compounds that mimic the chemical structures of poly(arylene ether)s confirmed that electron-withdrawing groups near to the aryl ether bonds in the repeating unit acc...