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Aims: Neointimal formation remains a major limitation after arterial reconstruction. To overcome this problem, we focused on two important transcription factors, nuclear factor-kappaB (NFκB) and E2F. The purpose of this study was to determine the effects of simultaneous inhibition of these transcription factors on the formation of neointimal hyperplasia. [ABSTRACT FROM PUBLISHER]

The discovery of monolayer graphene has initiated two fertile fields in condensed matter physics: Dirac semimetals and atomically thin layered materials. When these trends meet again in transition metal compounds, which possess spin and orbital degrees of freedom and strong electron correlations, more exotic phenomena are expected to emerge in the cross section of topological states of matter and Mott physics. Here, we show by using ab initio calculations that a monolayer form of transition metal trichalcogenides (TMTs), which has a honeycomb network of 4 d and 5 d transition metal cations, may exhibit multiple Dirac cones in the electronic structure of the half-filled e g orbitals. The Dirac cones are gapped by the spin-orbit coupling under the trigonal lattice distortion and, hence, can be tuned by tensile strain. Furthermore, we show that electron correlations and carrier doping turn the multiple Dirac semimetal into a topological ferromagnet with high Chern number. Our findings indicate that the honeycomb-monolayer TMTs provide a good playground for correlated Dirac electrons and topologically nontrivial magnetism. [ABSTRACT FROM AUTHOR]

We propose a refined scheme of deriving an effective low-energy Hamiltonian for materials with strong electronic Coulomb correlations beyond density functional theory (DFT). By tracing out the electronic states away from the target degrees of freedom in a controlled way by a perturbative scheme, we construct an effective Hamiltonian for a restricted low-energy target space incorporating the effects of high-energy degrees of freedom in an effective manner. The resulting effective Hamiltonian can afterwards be solved by accurate many-body solvers. We improve this "multiscale ab initio scheme for correlated electrons" (MACE) primarily in two directions by elaborating and combining two frameworks developed by Hirayama et al. [M. Hirayama, T. Miyake, and M. Imada, Phys. Rev. B 87, 195144 (2013)] and Casula et al. [M. Casula, P. Werner, L. Vaugier, F. Aryasetiawan, T. Miyake, A. J. Millis, and S. Biermann, Phys. Rev. Lett. 109, 126408 (2012)]: (1) Double counting of electronic correlations between the DFT and the low-energy solver is avoided by using the constrained G W scheme; and (2) the frequency dependent interactions emerging from the partial trace summation are successfully separated into a nonlocal part that is treated following ideas by Hirayama et al. and a local part treated nonperturbatively in the spirit of Casula et al. and are incorporated into the renormalization of the low-energy dispersion. The scheme is favorably tested on the example of SrVO3. [ABSTRACT FROM AUTHOR]

Abdominal aortic aneurysm (AAA) is a common degenerative condition with high mortality in older men. Elective surgical or endovascular repair is performed to prevent rupture of large AAAs. In contrast, despite gradual expansion, small AAAs have a low risk of rupture, and there is currently no well-defined treatment strategy for them. Therefore, a pharmacological approach for AAA is expected in the clinical setting. Indeed, several therapeutic effects of pharmacological agents have been reported in experimental models, and some agents have undergone clinical trials. Treatment with statins, angiotensin-converting enzyme-inhibitors, antibiotics, and anti-inflammatory agents appears to inhibit the growth rate of AAA in humans. However, as the sample size and follow-up period were limited in these studies, a large randomized study with long-term follow-up of small AAA should be performed to clarify the effect of these agents. Recently, the regression of AAA using molecular pharmacological approaches was reported in experimental studies. The characteristics of these strategies are the regulation of multiple molecular mediators and the signalling networks associated with AAA formation. On the basis of the results of these investigations, it may be possible to repair the injured aortic wall and obtain the remission of AAA using pharmacological therapy. [ABSTRACT FROM AUTHOR]

Electronic and magnetic properties of molybdenum pyrochlores A2Mo2O7 are studied by the fully relativistic density-functional theory plus on-site repulsion (U) method, with a focus on the spin-glass insulating material Y2Mo2O7. We find that the system exhibits peculiar competition in energy between different magnetic states in the large-U insulating region. The magnetic competition cannot be explained by the conventional picture based on the geometrical frustration of isotropic Heisenberg antiferromagnetic exchange interactions. Through an analysis by using a generalized spin model, we find that the effective spin interactions are distinct from the simple Heisenberg form and strongly anisotropic in spin space. We also reveal that they give rise to keen competition between antiferromagnetic and ferromagnetic states. The complex form of the magnetic interactions indicates a crucial role of the orbital degree of freedom. Analyzing a three-orbital Hubbard model, we clarify that the magnetic competition is tightly connected with orbital frustration in the 4d² electronic configuration through the spin-orbital interplay. The results challenge the conventional picture of the spin-glass behavior that attributes the origin to the geometrical frustration of purely antiferromagnetic exchange interactions. [ABSTRACT FROM AUTHOR]

We present a first-principles investigation of NdFe12 and NdFe12X (X = B, C, N, O, and F) crystals with the ThMn12 structure. Intersite magnetic couplings in these compounds, the so-called exchange couplings, are estimated by using Liechtenstein’s method. It is found that the Nd–Fe couplings are sensitive to the interstitial dopant X, with the Nd–Fe(8j) coupling in particular reduced significantly for X = N. This suggests that magnetocrystalline anisotropy decays quickly with rising temperature in the X = N system although nitrogenation has advantages over other dopants in terms of enhancing low-temperature magnetic properties. The Curie temperature is also calculated from the magnetic couplings by using the mean field approximation. Introduction of X enhances the Curie temperature, with both structural changes and chemical effects found to play important roles in this enhancement. [ABSTRACT FROM AUTHOR]

Recently synthesized NdFe12N has excellent magnetic properties, while it is thermodynamically unstable. Using the first-principles method, we study the effect of substitutional 3d transition metal elements to the mother compound NdFe12. We find that Co has a positive effect on the stability of the ThMn12 structure. In contrast to Ti substitution, Co substitution does not reduce the magnetization significantly. The crystal field parameter hr²iA20 is nearly unchanged by Co substitution, and nitrogenation to NdFe11Co greatly enhances hr²iA20. This suggests that Co is a good candidate as a substitutional element for NdFe12N. [ABSTRACT FROM AUTHOR]

We demonstrate that knowledge of chemical physics on a materials system can be automatically extracted from first-principles calculations using a data mining technique; this information can then be utilized to construct a simple empirical atomic potential model. By using unsupervised learning of the generative Gaussian mixture model, physically meaningful patterns of atomic local chemical environments can be detected automatically. Based on the obtained information regarding these atomic patterns, we propose a chemical-structure-dependent linear mixture model for estimating the atomic potential energy. Our experiments show that the proposed mixture model significantly improves the accuracy of the prediction of the potential energy surface for complex systems that possess a large diversity in their local structures. [ABSTRACT FROM AUTHOR]

A classical spin model derived ab initio for rare-earth-based permanent magnet compounds is presented. Our target compound, NdFe12N, is a material that goes beyond today's champion magnet compound Nd2Fe14B in its intrinsic magnetic properties with a simpler crystal structure. Calculated temperature dependence of the magnetization and the anisotropy field agrees with the latest experimental results in the leading order. Having put the realistic observables under our numerical control, we propose that engineering 5d-electron-mediated indirect exchange coupling between 4f-electrons in Nd and 3d-electrons from Fe would most critically help enhance the material's utility over the operation-temperature range. [ABSTRACT FROM AUTHOR]

Recent progress in understanding the electronic band topology and emergent topological properties encourage us to reconsider the band structure of well-known materials including elemental substances. Controlling such a band topology by external field is of particular interest from both fundamental and technological viewpoints. Here we report possible signatures of the pressure-induced topological phase transition from a semiconductor to a Weyl semimetal in elemental tellurium probed by transport measurements. Pressure variation of the periods of Shubnikov-de Haas oscillations, as well as oscillation phases, shows an anomaly around the pressure theoretically predicted for topological phase transition. This behavior is consistent with the pressure-induced band deformation and resultant band-crossing effect. Moreover, effective cyclotron mass is reduced toward the critical pressure, potentially reflecting the emergence of massless linear dispersion. The present result paves the way for studying the electronic band topology in well-known compounds and topological phase transition by the external field. [ABSTRACT FROM AUTHOR]

We apply the first-principles density functional theory + dynamical mean-field theory framework to evaluate the crystal-field splitting on rare-earth sites in hard magnetic intermetallics. An atomic (Hubbard-I) approximation is employed for local correlations on the rare-eart 4f shell and self-consistency in the charge density is implemented. We reduce the density functional theory self-interaction contribution to the crystal-field splitting by properly averaging the 4f charge density before recalculating the one-electron Kohn-Sham potential. Our approach is shown to reproduce the experimental crystal-field splitting in the prototypical rare-earth hard magnet SmCo5. Applying it to RFe12 and RFe12X hard magnets (R=Nd, Sm and X=N, Li), we obtain in particular a large positive value of the crystal-field parameter A20〈r²〉 in NdFe12N resulting in a strong out-of-plane anisotropy observed experimentally. The sign of A20〈r²〉 is predicted to be reversed by substituting N with Li, leading to a strong out-of-plane anisotropy in SmFe12Li. We discuss the origin of this strong impact of N and Li interstitials on the crystal-field splitting on rare-earth sites. [ABSTRACT FROM AUTHOR]

We study magnetic properties of NdFe11TiX, where X=B, C, N, O, and F, by using first-principles calculations based on density functional theory. Its parent compound NdFe11Ti has the ThMn12 structure, which has the symmetry of space group I4/mmm, No. 139. The magnetization increases by doping B, C, N, O, and F at the 2b site of the ThMn12 structure. The amount of the increase is larger for X=N, O, F than for X=B, C. On the other hand, the crystal field parameter A20, which controls the axial magnetic anisotropy of the Nd 4f magnetic moment, depends differently on the dopant. With increase of the atomic number from X=B, A20 increases, takes a maximum value for X=N, and then turns to decrease. This suggests that in NdFe11TiX, nitrogen is the most appropriate dopant among B, C, N, O, and F for permanent magnets in terms of magnetization and anisotropy. The above calculated properties are explained based on the detailed analysis of the electronic structures of NdFe11TiX. [ABSTRACT FROM AUTHOR]

We study Weyl nodes in materials with broken inversion symmetry. We find based on first-principles calculations that trigonal Te and Se have multiple Weyl nodes near the Fermi level. The conduction bands have a spin splitting similar to the Rashba splitting around the H points, but unlike the Rashba splitting the spin directions are radial, forming a hedgehog spin texture around the H points, with a nonzero Pontryagin index for each spin-split conduction band. The Weyl semimetal phase, which has never been observed in real materials without inversion symmetry, is realized under pressure. The evolution of the spin texture by varying the pressure can be explained by the evolution of the Weyl nodes in k space. [ABSTRACT FROM AUTHOR]

We calculate the electronic structure of Sr2RuO4, treating correlations within dynamical mean-field theory. The approach successfully reproduces several experimental results and explains the key properties of this material: the anisotropic mass renormalization of quasiparticles and the crossover into an incoherent regime above a low temperature scale. While the orbital differentiation originates from the proximity of the van Hove singularity, strong correlations are caused by the Hund's coupling. The generality of this mechanism for other correlated materials is pointed out. [ABSTRACT FROM AUTHOR]

The long-term maintenance of hematopoietic stem cells (HSCs) is assessed by serial bone marrow transplantation (BMT), in which HSCs are injected intravenously. Recently, we have found that intra-bone marrow (IBM)–BMT can efficiently reconstitute the hematopoietic system with cells of donor origin, in contrast to conventional intravenous (IV) BMT. In the present study, we have compared the long-term maintenance of HSCs using multiple rounds of serial IV-BMT and IBM-BMT. The frequencies of donor-derived progenitor cells (Lin−c-kitcells) and more primitive progenitors (Lin−c-kitCD34Sca-1cells) were higher in the tertiary recipients by serial IBM-BMT than in those that had received bone marrow cells by serial IV-BMT. Furthermore, neither donor-derived progenitor cells nor mature hematolymphoid cells were detected in ∼25 of the tertiary recipients after serial IV-BMT, indicating that progenitor cells can be efficiently maintained by IBM-BMT but not by IV-BMT. Finally, we confirmed that the recipients treated with the primary IBM-BMT (without carrying out serial BMT) showed a significantly higher survival rate than those treated with IV-BMT. These findings clearly show that IBM-BMT efficiently promotes the longterm maintenance of donor-derived hematopoiesis. [ABSTRACT FROM AUTHOR]

We investigate the effects of magnetic inhomogeneities and thermal fluctuations on the magnetic properties of a rare-earth intermetallic compound, Nd2Fe14B. The constrained Monte Carlo method is applied to a Nd2Fe14B bulk system to realize the experimentally observed spin reorientation and magnetic anisotropy constants KAm (m = 1,2,4) at finite temperatures. Subsequently, it is found that the temperature dependence of KA1 deviates from the Callen-Callen law, KA1(T)∝M(T)³, even above room temperature, TR~300K, when the Fe (Nd) anisotropy terms are removed to leave only the Nd (Fe) anisotropy terms. This is because the exchange couplings between Nd moments and Fe spins are much smaller than those between Fe spins. It is also found that the exponent n in the external magnetic field Hext response of barrier height FB = F0B(1-Hext/H0)n is less than 2 in the low-temperature region below TR, whereas n approaches 2 when T>TR, indicating the presence of Stoner-Wohlfarth-type magnetization rotation. This reflects the fact that the magnetic anisotropy is mainly governed by the KA1 term in the T>TR region. [ABSTRACT FROM AUTHOR]