J_{eff}=1/2 Hyperoctagon Lattice in Cobalt Oxalate Metal-Organic Framework.

We report the magnetic properties of a cobalt oxalate metal-organic framework featuring the hyperoctagon lattice. Our thermodynamic measurements reveal the J_{eff}=1/2 state of the high-spin Co^{2+} (3d^{7}) ion and the two successive magnetic transitions at zero field with two-stage entropy release. ^{13}C-NMR measurements reveal the absence of an internal magnetic field in the intermediate temperature phase. Multiple field-induced phases are observed before full saturation at around 40 T. We argue the unique cobalt oxalate network gives rise to the Kitaev interaction and/or a bond frustration effect, providing an unconventional platform for frustrated magnetism on the hyperoctagon lattice.

Magnon thermal Hall effect via emergent SU(3) flux on the antiferromagnetic skyrmion lattice.

Complexity of quantum phases of matter is often understood theoretically by using gauge structures, as is recognized by the [Formula: see text] and U(1) gauge theory description of spin liquids in frustrated magnets. Anomalous Hall effect of conducting electrons can intrinsically arise from a U(1) gauge expressing the spatial modulation of ferromagnetic moments or from an SU(2) gauge representing the spin-orbit coupling effect. Similarly, in insulating ferro and antiferromagnets, the magnon contribution to anomalous transports is explained in terms of U(1) and SU(2) fluxes present in the ordered magnetic structure. Here, we report thermal Hall measurements of MnSc2S4 in an applied field up to 14 T, for which we consider an emergent higher rank SU(3) flux, controlling the magnon transport. The thermal Hall coefficient takes a substantial value when the material enters a three-sublattice antiferromagnetic skyrmion phase, which is in agreement with the linear spin-wave theory. In our description, magnons are dressed with SU(3) gauge field, which is a mixture of three species of U(1) gauge fields originating from the slowly varying magnetic moments on these sublattices.

Titanium Hydride Complex BaCa2Ti2H14 with 9-Fold Coordination.

We present the high-pressure synthesis and crystal structure of a novel titanium hydride complex, BaCa2Ti2H14, with 9-fold coordination. It comprises a unique dinuclear [Ti2H14]6- complex that consists of a pair of Ti4+ ions each coordinated by nine hydrides in the monocapped square antiprism, distinguished from the known 9-fold coordination in the mononuclear tricapped trigonal prism of [MH9]x-. The dinuclear hydride complex is stabilized by three-center two-electron bonding at the four bridging Ti-H-Ti bonds to compensate for the lack of valence electrons in the Ti4+ ions. Optical measurements show that BaCa2Ti2H14 is a band insulator with a wide band gap of 2.25 eV. Density functional theory calculations reveal that the top of the valence band is dominated by H-1s-derived states, as expected from the 9-fold coordination, which would present a playground for electronic properties such as high-Tc superconductivity when doped with hole carriers or under high pressure.

Impact of proprioception during the oral phase on initiating the swallowing reflex.

OBJECTIVES/HYPOTHESIS: We hypothesized that proprioceptive signals during the oral phase play a pivotal role in the initiation of pharyngeal phase during volitional swallowing. Therefore, we tested if swallowing could be modified by changing the amount of proprioceptive feedback from a number of different receptors while holding a food bolus in the mouth and clenching. STUDY DESIGN: Basic research. METHODS: Surface electromyography (sEMG) recordings of the masticatory muscles were obtained during volitional swallowing movements from seven healthy adults with no clinical history of swallowing difficulties. The swallowing procedure involved holding 5 ml of jelly on the tongue before swallowing it completely, according to visual cues on a computer display. Initiation of the swallowing reflex was detected by an anterior shift of the thyroid cartilage using a laser displacement sensor and by submental sEMG signals. To vary the proprioceptive input, the participants were instructed to occlude their teeth at various intensities (weak, intermediate, and strong) while holding the 5-ml jelly bolus on the tongue. RESULTS: Rectified and integrated sEMG (iEMG) signals obtained from the submental area showed two upward deflections. Contractile forces of the masseter muscles showed significant negative values for Pearson correlation coefficient against time intervals from the onset of the second submental iEMG deflection to the onset of the anterior shift of the thyroid cartilage in six of the seven participants (average -0.534, standard deviation 0.176). CONCLUSION: Contractile forces of the masseter muscles during occlusion tended to correlate negatively with electromechanical delays on suprahyoid muscle contraction. LEVEL OF EVIDENCE: NA Laryngoscope, 126:1595-1599, 2016.

Cu substitution effects on the local magnetic properties of Ba(Fe(1-x)Cu(x))(2)As(2): a site-selective (75)As and (63)Cu NMR study.

We take advantage of the site-selective nature of the ^{75}As and ^{63}Cu NMR techniques to probe the Cu substitution effects on the local magnetic properties of the FeAs planes in Ba(Fe_{1-x}Cu_{x})_{2}As_{2}. We show that the suppression of antiferromagnetic Fe spin fluctuations induced by Cu substitution is weaker than a naive expectation based on a simple rigid band picture, in which each Cu atom would donate three electrons to the FeAs planes. Comparison between ^{63}Cu and ^{75}As NMR data indicates that spin fluctuations are suppressed at the Cu and their neighboring Fe sites in the tetragonal phase, suggesting the strongly local nature of the Cu substitution effects. We attribute the absence of a large superconducting dome in the phase diagram of Ba(Fe_{1-x}Cu_{x})_{2}As_{2} to the emergence of a nearly magnetically ordered FeAs plane under the presence of orthorhombic distortion.

An orbital-selective spin liquid in a frustrated heavy fermion spinel LiV2O4.

The pronounced enhancement of the effective mass is the primary phenomenon associated with strongly correlated electrons. In the presence of local moments, the large effective mass is thought to arise from Kondo coupling, the interaction between itinerant and localized electrons. However, in d electron systems, the origin is not clear because of the competing Hund's rule coupling. Here we experimentally address the microscopic origin for the heaviest d fermion in a vanadium spinel LiV(2)O(4) having geometrical frustration. Utilizing orbital-selective (51)V NMR, we elucidate the orbital-dependent local moment that exhibits no long-range magnetic order despite persistent antiferromagnetic correlations. A frustrated spin liquid, Hund-coupled to itinerant electrons, has a crucial role in forming heavy fermions with large residual entropy. Our method is important for the microscopic observation of the orbital-selective localization in a wide range of materials including iron pnictides, cobaltates, manganites and ruthnates.

The vitamin D receptor is a Wnt effector that controls hair follicle differentiation and specifies tumor type in adult epidermis.

We have investigated how Wnt and vitamin D receptor signals regulate epidermal differentiation. Many epidermal genes induced by beta-catenin, including the stem cell marker keratin 15, contain vitamin D response elements (VDREs) and several are induced independently of TCF/Lef. The VDR is required for beta-catenin induced hair follicle formation in adult epidermis, and the vitamin D analog EB1089 synergizes with beta-catenin to stimulate hair differentiation. Human trichofolliculomas (hair follicle tumours) are characterized by high nuclear beta-catenin and VDR, whereas infiltrative basal cell carcinomas (BCCs) have high beta-catenin and low VDR levels. In mice, EB1089 prevents beta-catenin induced trichofolliculomas, while in the absence of VDR beta-catenin induces tumours resembling BCCs. We conclude that VDR is a TCF/Lef-independent transcriptional effector of the Wnt pathway and that vitamin D analogues have therapeutic potential in tumors with inappropriate activation of Wnt signalling.

Human sebaceous tumors harbor inactivating mutations in LEF1.

We found that one-third of human sebaceous tumors examined had double-nucleotide substitutions in the same LEF1 allele, irrespective of DNA mismatch repair status. The mutations impaired both LEF1 binding to beta-catenin and transcriptional activation, and are the first tumor-associated mutations that inactivate Wnt signaling. Mutant LEF1 not only inhibited expression of beta-catenin target genes but also stimulated expression of sebocyte markers, suggesting that it may determine the differentiated characteristics of sebaceous tumors.

Effects of angiotensin II receptor signaling during skin wound healing.

The tissue angiotensin (Ang) system, which acts independently of the circulating renin Ang system, is supposed to play an important role in tissue repair in the heart and kidney. In the skin, the role of the system for wound healing has remained to be ascertained. Our study demonstrated that oral administration of selective AngII type-1 receptor (AT(1)) blocker suppressed keratinocyte re-epithelization and angiogenesis during skin wound healing in rats. Immunoprecipitation and Western blot analysis indicated the existence of AT(1) and AngII type-2 receptor (AT(2)) in cultured keratinocytes and myofibroblasts. In a bromodeoxyuridine incorporation study, induction of AT(1) signaling enhanced the incorporation into keratinocytes and myofibroblasts. Wound healing migration assays revealed that induction of AT(1) signaling accelerated keratinocyte re-epithelization and myofibroblasts recovering. In these experiments, induction of AT(2) signaling acted vice versa. Taken together, our study suggests that skin wound healing is regulated by balance of opposing signals between AT(1) and AT(2).

Occurrence and comparison of the expressed keratins in cultured human fibroblasts, endothelial cells and their sarcomas.

We investigated keratin (K) expression in cultured fibroblasts, endothelial cells and their sarcomas by using two-dimensional gel electrophoresis and electron microscopy techniques. Although the fibroblast and endothelial cell lines were derived from mesenchyme, we confirmed Ks in both cell lines. The K in two cultured cell lines consisted of K14 and K16, together with vimentin. In addition to the above Ks, K5 and K8/K17 were comprised in each cell line, respectively. On the other hand, the cultured fibrosarcomas contained K8 and K18 in addition to the Ks present in the cultured fibroblasts, except K17. Moreover, cultured angiosarcomas showed the same Ks expression as those of the cultured fibrosarcomas, except vimentin. However, electron microscopy showed that the extremely thin fiber-like substances existed or at least did not form filamentous structures in four cultured cell types.