Enantioselective and Enantiospecific Transition-Metal-Catalyzed Cross-Coupling Reactions of Organometallic Reagents To Construct C–C Bonds

The stereocontrolled construction of C−C bonds remains one of the foremost challenges in organic synthesis. At the heart of any chemical synthesis of a natural product or designed small molecule is the need to orchestrate a series of chemical reactions to prepare and functionalize a carbon framework. The advent of transition-metal catalysis has provided chemists with a broad range of new tools to forge C−C bonds and has resulted in a paradigm shift in synthetic strategy planning. The impact of these methods was recognized with the awarding of the 2010 Nobel Prize in Chemistry to Richard Heck, Ei-ichi Negishi, and Akira Suzuki for their seminal contributions to the development of Pd-catalyzed cross-coupling

Tunneling magnetoresistance phenomenon utilizing graphene magnet electrode

Under the terms of the Creative Commons Attribution (CC BY) license to their work.Using magnetic rare-metals for spintronic devices is facing serious problems for the environmental contamination and the limited material-resource. In contrast, by fabricating ferromagnetic graphene nanopore arrays (FGNPAs) consisting of honeycomb-like array of hexagonal nanopores with hydrogen-terminated zigzag-type atomic structure edges, we reported observation of polarized electron spins spontaneously driven from the pore edge states, resulting in rare-metal-free flat-energy-band ferromagnetism. Here, we demonstrate observation of tunneling magnetoresistance (TMR) behaviors on the junction of cobalt/SiO2/FGNPA electrode, serving as a prototype structure for future rare-metal free TMR devices using magnetic graphene electrodes. Gradual change in TMR ratios is observed across zero-magnetic field, arising from specified alignment between pore-edge- and cobalt-spins. The TMR ratios can be controlled by applying back-gate voltage and by modulating interpore distance. Annealing the SiO2/FGNPA junction also drastically enhances TMR ratios up to ~100%.This work at Aoyama Gakuin was partly supported by a Grant-in-aid for Scientific Research (Basic research A: 24241046) in MEXT and AFOSR grant. The work by J.G.P. was financially supported by the Danish Council for Independent Research, FTP Grant Nos. 11-105204 and 11-120941. S.R. and D.S. acknowledge financial support by the Spanish Ministry of Economy and Competitiveness (MAT2012-33911).Peer Reviewe

Integrating organic light-emitting diode and field-effect-transistor in a single device

ArticleORGANIC ELECTRONICS. 9(3): 323-327 (2008)journal articl

Magnetic properties of the S=1/2S=1/2 distorted diamond chain at T=0

We explore, at T=0, the magnetic properties of the $S=1/2$ antiferromagnetic distorted diamond chain described by the Hamiltonian {\cal H} = \sum_{j=1}^{N/3}{J_1 ({\bi S}_{3j-1} \cdot {\bi S}_{3j} + {\bi S}_{3j} \cdot {\bi S}_{3j+1}) + J_2 {\bi S}_{3j+1} \cdot {\bi S}_{3j+2} + J_3 ({\bi S}_{3j-2} \cdot {\bi S}_{3j} + {\bi S}_{3j} \cdot {\bi S}_{3j+2})} \allowbreak - H \sum_{l=1}^{N} S_l^z with $J_1, J_2, J_3\ge0$, which well models ${\rm A_3 Cu_3 (PO_4)_4}$ with ${\rm A = Ca, Sr}$, ${\rm Bi_4 Cu_3 V_2 O_{14}}$ and azurite $\rm Cu_3(OH)_2(CO_3)_2$. We employ the physical consideration, the degenerate perturbation theory, the level spectroscopy analysis of the numerical diagonalization data obtained by the Lanczos method and also the density matrix renormalization group (DMRG) method. We investigate the mechanisms of the magnetization plateaux at $M=M_s/3$ and $M=(2/3)M_s$, and also show the precise phase diagrams on the $(J_2/J_1, J_3/J_1)$ plane concerning with these magnetization plateaux, where $M=\sum_{l=1}^{N} S_l^z$ and $M_s$ is the saturation magnetization. We also calculate the magnetization curves and the magnetization phase diagrams by means of the DMRG method.Comment: 21 pages, 29 figure

Separate Origins of Group I Introns in Two Mitochondrial Genes of the Katablepharid Leucocryptos marina

Mitochondria are descendants of the endosymbiotic α-proteobacterium most likely engulfed by the ancestral eukaryotic cells, and the proto-mitochondrial genome should have been severely streamlined in terms of both genome size and gene repertoire. In addition, mitochondrial (mt) sequence data indicated that frequent intron gain/loss events contributed to shaping the modern mt genome organizations, resulting in the homologous introns being shared between two distantly related mt genomes. Unfortunately, the bulk of mt sequence data currently available are of phylogenetically restricted lineages, i.e., metazoans, fungi, and land plants, and are insufficient to elucidate the entire picture of intron evolution in mt genomes. In this work, we sequenced a 12 kbp-fragment of the mt genome of the katablepharid Leucocryptos marina. Among nine protein-coding genes included in the mt genome fragment, the genes encoding cytochrome b and cytochrome c oxidase subunit I (cob and cox1) were interrupted by group I introns. We further identified that the cob and cox1 introns host open reading frames for homing endonucleases (HEs) belonging to distantly related superfamilies. Phylogenetic analyses recovered an affinity between the HE in the Leucocryptos cob intron and two green algal HEs, and that between the HE in the Leucocryptos cox1 intron and a fungal HE, suggesting that the Leucocryptos cob and cox1 introns possess distinct evolutionary origins. Although the current intron (and intronic HE) data are insufficient to infer how the homologous introns were distributed to distantly related mt genomes, the results presented here successfully expanded the evolutionary dynamism of group I introns in mt genomes

Industrial associations as ideational platforms : why Japan resisted American-style shareholder capitalism

Significant wage and treatment differentials between regular workers in long-term employment and precarious non-regular workers have been a major political issue in Japan since the mid-1990s. I argue this phenomenon was caused by Japanese society’s resistance to American neoliberal hegemony. Why has Japan resisted it, and how has the resistance resulted in the rapid increase in the working poor? I contend anti-liberal, anti-free market norms of Japanese society centred on ‘systemic support’ have bolstered resistance to convergence in order to prevent capitalist dominance from severing long-term social ties, such as management-labour cooperation. My broadened definition of systemic support incorporates dominant elites’ support and protection of subordinates in exchange for their loyalty and obedience. This paper will explore reasons for the resistance to convergence by examining an ideational conflict within Japanese elites between the market liberalisation and anti-free market camps, particularly between two major industrial associations, Keidanren and Keizai Doyukai, which have played a key role as ‘ideational platforms’ for Japanese corporate society. Under the Hashimoto (1996-8) and Koizumi (2001-6) administrations, the market liberalisation camp gained influence, but since 2006, both the anti-free market camp and its subordinates (e.g. regular workers) have driven anti-neoliberal backlash

New forming method of manufacturing cylindrical parts with nano/ultrafine grained structures by power spinning based on small plastic strains

A new spinning method to manufacture the cylindrical parts with nano/ultrafine grained structures is proposed, which consists of quenching, power spinning and recrystallization annealing. The microstructural evolution during the different process stages and macroforming quality of the spun parts made of ASTM 1020 steel are investigated. The results show that the microstructures of the ferrites and pearlites in the ASTM 1020 steel are transformed to the lath martensites after quenching. The martensite laths obtained by quenching are refined to 87 nm and a small amount of nanoscale deformation twins with an average thickness of 20 nm is generated after performing a 3-pass stagger spinning with 55% thinning ratio of wall thickness, where the equivalent strain required is only 0.92. The equiaxial ferritic grains with an average size of 160 nm and nano-carbides are generated by subsequent recrystallization annealing at 480°C for 30 min. The spun parts with high dimensional precision and low surface roughness are obtained by the forming method developed in this work, combining quenching with 3-pass stagger spinning and recrystallization annealing

Distribution and Phylogeny of EFL and EF-1α in Euglenozoa Suggest Ancestral Co-Occurrence Followed by Differential Loss

BACKGROUND: The eukaryotic elongation factor EF-1alpha (also known as EF1A) catalyzes aminoacyl-tRNA binding by the ribosome during translation. Homologs of this essential protein occur in all domains of life, and it was previously thought to be ubiquitous in eukaryotes. Recently, however, a number of eukaryotes were found to lack EF-1alpha and instead encode a related protein called EFL (for EF-Like). EFL-encoding organisms are scattered widely across the tree of eukaryotes, and all have close relatives that encode EF-1alpha. This intriguingly complex distribution has been attributed to multiple lateral transfers because EFL's near mutual exclusivity with EF-1alpha makes an extended period of co-occurrence seem unlikely. However, differential loss may play a role in EFL evolution, and this possibility has been less widely discussed. METHODOLOGY/PRINCIPAL FINDINGS: We have undertaken an EST- and PCR-based survey to determine the distribution of these two proteins in a previously under-sampled group, the Euglenozoa. EF-1alpha was found to be widespread and monophyletic, suggesting it is ancestral in this group. EFL was found in some species belonging to each of the three euglenozoan lineages, diplonemids, kinetoplastids, and euglenids. CONCLUSIONS/SIGNIFICANCE: Interestingly, the kinetoplastid EFL sequences are specifically related despite the fact that the lineages in which they are found are not sisters to one another, suggesting that EFL and EF-1alpha co-occurred in an early ancestor of kinetoplastids. This represents the strongest phylogenetic evidence to date that differential loss has contributed to the complex distribution of EFL and EF-1alpha