Origin of High-Temperature Superconductivity in Compressed LaH10_{10}

Room-temperature superconductivity has been one of the most challenging subjects in modern physics. Recent experiments reported that lanthanum hydride LaH$_{10{\pm}x}$ ($x$$<$1) raises a superconducting transition temperature $T_{\rm c}$ up to ${\sim}$260 (or 215) K at high pressures around 190 (150) GPa. Here, based on first-principles calculations, we reveal the existence of topological Dirac-nodal-line (DNL) states in compressed LaH$_{10}$. Remarkably, the DNLs protected by the combined inversion and time-reversal symmetry and the rotation symmetry create a van Hove singularity (vHs) near the Fermi energy, giving rise to large electronic density of states. Contrasting with other La hydrides containing cationic La and anionic H atoms, LaH$_{10}$ shows a peculiar characteristic of electrical charges with anionic La and both cationic and anionic H species, caused by a strong hybridization of the La $f$ and H $s$ orbitals. We find that a large number of electronic states at the vHs are strongly coupled to the H-derived high-frequency phonon modes that are induced via the unusual, intricate bonding network of LaH$_{10}$, thereby yielding a high $T_{\rm c}$. Our findings not only elucidate the microscopic origin of the observed high-$T_{\rm c}$ BCS-type superconductivity in LaH$_{10}$, but also pave the route for achieving room-temperature topological superconductors in compressed hydrogen-rich compounds.Comment: 9 pages, 11 figure

Effects of positively charged arginine residues on membrane pore forming activity of Rev–NIS peptide in bacterial cells

AbstractHere, we investigated antibacterial effects of Rev–NIS and suggested the role of positively charged amino acids on membrane pore forming activity of the peptide in bacterial cells, by synthesizing two analogs, Anal R and Anal S. Based on the amphipathic property of Rev–NIS, Anal R and Anal S were designed by substituting E1 and L3 to R and L3 to S, respectively. The circular dichroism (CD) spectroscopy showed that Anal R and Anal S have the same conformation of Rev–NIS, with a significant fraction of helical structure. In succession, the antibacterial susceptibility testing showed that Rev–NIS and its analogs possessed significant activities (Anal R>Rev–NIS>Anal S), without hemolytic effects, against bacterial pathogens including antibiotics-resistant strains. Moreover, the membrane studies, 3,3′-dipropylthiadicarbocyanine iodide (diSC35) staining and FITC-dextran (FD) leakage assay demonstrated that the analogs as well as Rev–NIS acted on the bacterial membranes and potently made pores, with the hydrodynamic radius between 1.4nm and 2.3nm. Especially, Anal R made larger pores than other peptides, with the radius between 2.3nm and 3.3nm. These results also corresponded to the result of antibacterial susceptibility testing. In summary, this study indicates that the two arginine residues are more influential than the hydrophobicity or the helicity, regarding the molecular activity of the peptide, and finally suggests that Anal R peptide may be applied to novel antibacterial agents

OF@TEIN: An OpenFlow-enabled SDN Testbed over International SmartX Rack Sites

In this paper, we will discuss our on-going effort for OF@TEIN SDN(Software-Defined Networking) testbed, which currently spans over Korea and fiveSouth-East Asian (SEA) collaborators with internationally deployed OpenFlowenabledSmartX Racks

Predictive biomarkers for 5-fluorouracil and oxaliplatin-based chemotherapy in gastric cancers via profiling of patient-derived xenografts.

Gastric cancer (GC) is commonly treated by chemotherapy using 5-fluorouracil (5-FU) derivatives and platinum combination, but predictive biomarker remains lacking. We develop patient-derived xenografts (PDXs) from 31 GC patients and treat with a combination of 5-FU and oxaliplatin, to determine biomarkers associated with responsiveness. When the PDXs are defined as either responders or non-responders according to tumor volume change after treatment, the responsiveness of PDXs is significantly consistent with the respective clinical outcomes of the patients. An integrative genomic and transcriptomic analysis of PDXs reveals that pathways associated with cell-to-cell and cell-to-extracellular matrix interactions enriched among the non-responders in both cancer cells and the tumor microenvironment (TME). We develop a 30-gene prediction model to determine the responsiveness to 5-FU and oxaliplatin-based chemotherapy and confirm the significant poor survival outcomes among cases classified as non-responder-like in three independent GC cohorts. Our study may inform clinical decision-making when designing treatment strategies

Strain-induced single-crystalline AgCl nanorods for optoelectronic devices

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脱細胞化肝臓の作製条件最適化法の確立

主1工学_物質プロセス工

Highly transparent hazy film for reducing angular color shift in cavity organic light-emitting diodes

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Unit cell engineering for achromatic metalens in visible

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