Electronic and Magnetic Properties of Nanographite Ribbons

Electronic and magnetic properties of ribbon-shaped nanographite systems with zigzag and armchair edges in a magnetic field are investigated by using a tight binding model. One of the most remarkable features of these systems is the appearance of edge states, strongly localized near zigzag edges. The edge state in magnetic field, generating a rational fraction of the magnetic flux (\phi= p/q) in each hexagonal plaquette of the graphite plane, behaves like a zero-field edge state with q internal degrees of freedom. The orbital diamagnetic susceptibility strongly depends on the edge shapes. The reason is found in the analysis of the ring currents, which are very sensitive to the lattice topology near the edge. Moreover, the orbital diamagnetic susceptibility is scaled as a function of the temperature, Fermi energy and ribbon width. Because the edge states lead to a sharp peak in the density of states at the Fermi level, the graphite ribbons with zigzag edges show Curie-like temperature dependence of the Pauli paramagnetic susceptibility. Hence, it is shown that the crossover from high-temperature diamagnetic to low-temperature paramagnetic behavior of the magnetic susceptibility of nanographite ribbons with zigzag edges.Comment: 13 pages including 19 figures, submitted to Physical Rev

Seasonal distribution of Gambierdiscus spp. in Wakasa Bay, the Sea of Japan, and antagonistic relationships with epiphytic pennate diatoms

The occurrence of the ciguatera fish poisoning (CFP) causative Gambierdiscus spp. was confirmed in the Sea of Japan for the first time in 2009. This paper reports seasonal distribution of Gambierdiscus spp. and epiphytic diatoms in the Sea of Japan. Monitoring results suggested an antagonistic interaction in abundances between epiphytic diatoms and the dinoflagellate Gambierdiscus spp. Allelopathic effects of diatoms were considered to be involved in the competitive phenomenon. Therefore it is hypothesized that cell densities of epiphytic pennate diatoms on macroalgae are a novel determinant affecting the abundance of Gambierdiscus spp. other than sea water temperature, salinity and nutrients. Monitorings of the abundance of epiphytic diatoms would lead us to predict the occurrences of Gambierdiscus spp. blooms in the CFP area, and thereby the CFP risk assessments would be developed. Phylogenetic analyses indicated that Gambierdiscus spp. in the Sea of Japan belonged to Gambierdiscus sp. type 2 which was reported to be non-toxic. Nevertheless, based on morphological characteristics, at least two types of Gambierdiscus spp. were found in the Sea of Japan. It is needed to test the toxicity of the both types of Gambierdiscus recognized in the present study for evaluation of the probability of CFP outbreak risks in the Sea of Japan in the future

Development of Fast-Neutron Directional Detector for Fusion Neutron Profile Monitor at LHD

Fast-neutron directional detectors using scintillating optical fibers have been adopted for neutron emission profile measurement in magnetic confinement fusion devices. Because of their benefits of rapid response and directional properties to reduce restrictions on shielding, they are anticipated for installation in the Large Helical Device (LHD) of the National Institute for Fusion Science (NIFS). As described herein, the system design has been re-examined based on the results of recent experiments and simulations. Results show that fast neutrons with high energy of 14 MeV are attenuated by a self-shielding effect of scintillating fiber. Moreover, it has been demonstrated that the scintillation photons are attenuated in several centimeters before reaching the photon detector. The control of the photon transmission efficiency is important to enhance the directional property of the system. Along with reduced effects of the background gamma rays, adopting a thin scintillating fiber is effective. Further evaluation should be conducted to design a detector system considering the detecting efficiency, directional property, and gamma ray effect for application to an actual radiation field of the LHD

Additional file 1: Figure S1. of Genomic landscape of colorectal cancer in Japan: clinical implications of comprehensive genomic sequencing for precision medicine

Location of genetic aberrations for Japanese and US patients, and TCGA samples. Mutations in (A) APC, (B) ERBB2, (C) TP53, (D) NRAS, and (E) KRAS for Japanese patients (n = 201), US patients (n = 108), and TCGA samples (n = 224) were aligned to protein domains. The number of mutations at each given amino acid were plotted in corresponding pie graphs. As shown, KRAS G12 were the highest frequency mutations. Patient samples were further plotted by mutation status (F) KRAS-hypermutated and (G) KRAS-non-hypermutated. Figure S2. Correlation of RNF43 mutations with MMR. (A) The frequencies of APC and RNF43 mutations were determined by MMR phenotype. Statistical significance was determined by Fisher’s exact test. (B) Mutation mapper analysis identified G659 as most frequently altered in MMR-D cases. Figure S3. Gene-based statistical analysis for clinical information. Genes were filtered based on Fisher’s exact test (p < 0.05). Cell values are log odds ratios colored from blue to red. Dendrograms were created by Euclidean distance and Ward’s method. Less (blue) or more (red) aggressive factors of seven clinical variables are shown: lymphatic invasion (ly), vascular invasion (v), histopathological grade (G), TNM classifications (T, N, and M), and tumor stage. Figure S4. Cluster of 61-gene co-mutation patterns. (A) Cluster analysis was performed on non-hypermutated Japanese CRC samples (n = 184 tumors) by using Euclidean distance and Ward’s clustering method (closest distance to common mutated genes are colored yellow to blue). (B) Co-mutated gene patterns of the 61-gene set with statistical analysis. Mutation rate in each group is shown as a bar graph in the middle panel. Group-based mean values for age and tumor diameter are shown (left) with cluster colors and fraction for clinical information (right). Dark bars indicate significant difference (p < 0.05, two-tailed Fisher’s exact test) to the distribution of all other non-hypermutated donors, light bars are non-significant (**p < 0.01, *p < 0.05). Figure S5. Data complementary to Fig. 3. (A) Cluster analysis was performed on non-hypermutated Japanese CRC samples (n = 184 tumors) by using Euclidean distance and Ward’s clustering method (closest distance to common mutated genes are colored yellow to blue). (B) Kaplan–Meier survival estimates according to genomic subgroups. Overall survival was analyzed in 102 patients with Stage IV CRC treated with anti-EGFR therapies. The patients were divided to “All WT (wild type)” (Cluster 1; n = 25) or “Mutated” (Clusters 2–8; n = 77) based on the cluster analysis with targeted therapy-related 26 genes. Table S1. The 415-gene list for the CGS platform. Table S2. BRAF mutation and tumor location (J-CRC, n = 201). Table S3. Raw data for gene-based statistical analysis for clinical information. Table S4. Clinicopathological characteristics of 201 CRC patients. (PDF 1435 kb