Small anisotropy in iron-based superconductors induced by electron correlation

We have investigated the electron correlation effect on the electronic structures and transport properties of the iron-based superconductors using density functional theory (DFT) and dynamical mean field theory (DMFT). By considering the Fe 3d electron correlation using DMFT, the quasiparticle bandwidth near the Fermi level is found to be substantially suppressed compared to the conventional DFT calculation. Because of the different renormalization factors of each 3d orbital, DMFT gives considerably reduced electrical anisotropy compared to DFT results, which explains the unusually small anisotropic resistivity and superconducting property observed in the iron-based superconductors. We suggest that the electron correlation effect should be considered to explain the anisotropic transport properties of the general d/f valence electron system.close3

Orbital selective Fermi surface shifts and mechanism of high Tc_c superconductivity in correlated AFeAs (A=Li,Na)

Based on the dynamical mean field theory (DMFT) and angle resolved photoemission spectroscopy (ARPES), we have investigated the mechanism of high $T_c$ superconductivity in stoichiometric LiFeAs. The calculated spectrum is in excellent agreement with the observed ARPES measurement. The Fermi surface (FS) nesting, which is predicted in the conventional density functional theory method, is suppressed due to the orbital-dependent correlation effect with the DMFT method. We have shown that such marginal breakdown of the FS nesting is an essential condition to the spin-fluctuation mediated superconductivity, while the good FS nesting in NaFeAs induces a spin density wave ground state. Our results indicate that fully charge self-consistent description of the correlation effect is crucial in the description of the FS nesting-driven instabilities.Comment: 5 pages, 4 figures, supporting informatio

Low phonon conductivity of layered BiCuOS, BiCuOSe, and BiCuOTe from first principles

Combining the effect of layer mixing, mass mismatch, and intrinsic defects, we have investigated the origin of very low phonon conductivity k(p) in thermoelectric (TE) BiCuOQ (Q: S, Se, Te) compounds. Based on the first-principles anharmonic, lattice dynamics calculations, we use the single-mode relaxation time approximation of the linearized phonon Boltzmann equation, which shows good agreement with experiments. Here, we found that the most important parameter for low k(p) is the interlayer interaction between the BiO and CuQ layers. By analyzing the phonon linewidth distribution, which indicates the phonon scattering rate, we propose that the interlayer interactions play a critical role on suppressing k(p), i.e., the heterolayered crystal controls these interlayer interactions, achieving low k(p) and optimal TE properties.1133Ysciescopu

New Classification of Polydactyly of the Foot on the Basis of Syndactylism, Axis Deviation, and Metatarsal Extent of Extra Digit

Background  Polydactyly of the foot is one of the most frequent anomalies of the limbs.However, most classification systems are based solely on morphology and tend to be inaccu­rate and lessrelevantto surgical methods and results. The purpose ofthisstudy isto presentour newclassification of polydactyly ofthe foot,which can serve as a predictor oftreatmentand prognosis.Methods  To find a correlation between the various morphologic traits of polydactyly ofthe foot and the treatment plan and outcomes,we reviewed 532 cases of polydactyly ofthefoot in 431 patients treated in our hospital, expanding on our previous study that describedpolydactyly based on the importance of metatarsal bone status and varus deformity. Therecords of patientswere evaluated and comparedwith previousstudies at other centers.Results  Unsatisfactory results were seen in 36 cases, which included 5 cases of incompleteseparation due to syndactylism, 23 cases of axis deviation, and 8 cases ofremnants of extra­digit metatarsal bones. The locus of the polydactyly, or the digit which wasinvolved, did notseemto affectthe final postoperative outcomesin ourstudy. Three factors­syndactylism, axisdeviation, and metatarsal extension­are the major factors related to treatment strategy andprognosis. Therefore,we developed a newclassification systemusing three characters(S,A,M)followed by three groups(0, 1, 2),to describe the complexity of polydactyly ofthe foot,suchas S1A2M2.Conclusions  Our newclassification could provide a communicable description to help deter­mine the surgical plan and predict outcomes

Down-regulation of phosphoglucomutase 3 mediates sulforaphane-induced cell death in LNCaP prostate cancer cells

<p>Abstract</p> <p>Background</p> <p>Sulforaphane (SFN) is an isothiocyanate found in cruciferous vegetables that exerts anti-oxidant, anti-inflammatory, anti-cancer and radio-sensitizing activities. Nonetheless, the mechanism responsible for SFN-induced cell death is not fully understood. In the present study, anti-cancer mechanism of SFN was elucidated in LNCaP prostate cancer cells.</p> <p>Results</p> <p>SFN exerted cytotoxicity and increased TUNEL positive cells in a concentration-dependent manner in LNCaP cells. Proteomics study revealed that levels of nine proteins including tubulin β-2, phosphoglucomutase-3 (PGM3), melanoma-derived leucine zipper containing extra-nuclear factor, activin A type I receptor precursor, smoothelin-A, KIA0073, hypothetical protein LOC57691 and two unnamed proteins were changed over 8 folds in SFN treated LNCaP cells compared to untreated control. We have further confirmed that SFN reduced PGM3 expression with western blotting and showed that PGM3 siRNA enhanced cytotoxicity demonstrated by cell morphology and TUNEL assays in LNCaP cells.</p> <p>Conclusion</p> <p>Taken together, these findings suggest that PGM3 plays a role in mediating SFN-induced cell death in LNCaP cells, and is a potential molecular therapeutic target for prostate cancer.</p

Suppression of STAT3 and HIF-1 Alpha Mediates Anti-Angiogenic Activity of Betulinic Acid in Hypoxic PC-3 Prostate Cancer Cells

Background: Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. In the present study, we examined that betulinic acid (BA), a triterpene from the bark of white birch, had the inhibitory effects on hypoxia-mediated activation of STAT3 in androgen independent human prostate cancer PC-3 cells. Methodology/Principal Findings: BA inhibited the protein expression and the transcriptional activities of hypoxia-inducible factor-1a (HIF-1a) under hypoxic condition. Consistently, BA blocked hypoxia-induced phosphorylation, DNA binding activity and nuclear accumulation of STAT3. In addition, BA significantly reduced cellular and secreted levels of vascular endothelial growth factor (VEGF), a critical angiogenic factor and a target gene of STAT3 induced under hypoxia. Furthermore, BA prevented in vitro capillary tube formation in human umbilical vein endothelial cells (HUVECs) maintained in conditioned medium of hypoxic PC-3 cells, implying anti-angiogenic activity of BA under hypoxic condition. Of note, chromatin immunoprecipitation (ChiP) assay revealed that BA inhibited binding of HIF-1a and STAT3 to VEGF promoter. Furthermore, silencing STAT3 using siRNA transfection effectively enhanced the reduced VEGF production induced by BA treatment under hypoxia. Conclusions/Significance: Taken together, our results suggest that BA has anti-angiogenic activity by disturbing th