Neutron Spin Resonance in the 112-Type Iron-Based Superconductor.

We use inelastic neutron scattering to study the low-energy spin excitations of the 112-type iron pnictide Ca_{0.82}La_{0.18}Fe_{0.96}Ni_{0.04}As_{2} with bulk superconductivity below T_{c}=22 K. A two-dimensional spin resonance mode is found around E=11 meV, where the resonance energy is almost temperature independent and linearly scales with T_{c} along with other iron-based superconductors. Polarized neutron analysis reveals the resonance is nearly isotropic in spin space without any L modulations. Because of the unique monoclinic structure with additional zigzag arsenic chains, the As 4p orbitals contribute to a three-dimensional hole pocket around the Γ point and an extra electron pocket at the X point. Our results suggest that the energy and momentum distribution of the spin resonance does not directly respond to the k_{z} dependence of the fermiology, and the spin resonance intrinsically is a spin-1 mode from singlet-triplet excitations of the Cooper pairs in the case of weak spin-orbital coupling.

Field control of quasiparticle decay in a quantum antiferromagnet.

Dynamics in a quantum material is described by quantized collective motion: a quasiparticle. The single-quasiparticle description is useful for a basic understanding of the system, whereas a phenomenon beyond the simple description such as quasiparticle decay which affects the current carried by the quasiparticle is an intriguing topic. The instability of the quasiparticle is phenomenologically determined by the magnitude of the repulsive interaction between a single quasiparticle and the two-quasiparticle continuum. Although the phenomenon has been studied in several materials, thermodynamic tuning of the quasiparticle decay in a single material has not yet been investigated. Here we show, by using neutron scattering, magnetic field control of the magnon decay in a quantum antiferromagnet RbFeCl3, where the interaction between the magnon and continuum is tuned by the field. At low fields where the interaction is small, the single magnon decay process is observed. In contrast, at high fields where the interaction exceeds a critical magnitude, the magnon is pushed downwards in energy and its lifetime increases. Our study demonstrates that field control of quasiparticle decay is possible in the system where the two-quasiparticle continuum covers wide momentum-energy space, and the phenomenon of the magnon avoiding decay is ubiquitous.

Long-term prognosis of patients with Kawasaki disease complicated by giant coronary aneurysms: a single-institution experience.

BACKGROUND: Some patients with Kawasaki disease develop giant coronary aneurysms and coronary stenosis, leading to ischemic heart disease. The aim of this study was to determine the long-term prognosis of patients with Kawasaki disease with giant aneurysms. METHODS AND RESULTS: From our institutional database, 76 patients (57 men and 19 women) who developed giant aneurysms after January 1, 1972, were identified. Information on patient demographics, catheter and surgical interventions, and most recent status was collected from medical charts and patients' contacts. From these data, we calculated the survival rate and cumulative coronary intervention rate. The average age at onset was 2.9±2.9 years, and the median observational period was 19 years. During this period, 7 patients died and 1 patient underwent a heart transplantation, resulting in 95%, 88%, and 88% survival rates at 10, 20, and 30 years after the onset of KD, respectively. On the other hand, catheter and surgical coronary interventions (median, 1 intervention; range, 1 to 7 interventions) were performed to alleviate coronary ischemia in 46 patients (61%) at 1 month to 21 years (mode at 1 month) after onset, resulting in 28%, 43%, and 59% cumulative coronary intervention rates at 5, 15, and 25 years after onset, respectively. CONCLUSIONS: The long-term survival of patients with Kawasaki disease complicated by giant coronary aneurysms is moderately good with multiple catheter and surgical interventions. Further research should focus on the prevention of coronary vascular remodeling and on the indications for and effectiveness of percutaneous and surgical coronary interventions.

[A case of urethrovesical foreign body in an adolescent boy].

We report an unusual case of a 14-year old boy who presented with proteinuria and pyuria detected in a medical checkup at school. After denial of kidney disease, computed tomography of the pelvis showed a bladder stone with an internal low density and urethroscopy showed an odd stick at the prostatic urethra. Because of the failure of removal by the transurethral technique, he underwent suprapubic cystostomy against the foreign body stuck into the prostatic urethra. After surgery, he admitted that he had self-introduced a sewing instrument into the bladder for the purpose of masturbation one year three months previously.

Antiferromagnetic Kitaev interaction inJeff=1/2 cobalt honeycomb materials Na3Co2SbO6and Na2Co2TeO6.

Finding new materials with antiferromagnetic (AFM) Kitaev interaction is an urgent issue for quantum magnetism research. We conclude that Na3Co2SbO6and Na2Co2TeO6are new honeycomb cobalt-based systems with AFM Kitaev interaction by carrying out inelastic neutron scattering experiments and subsequent analysis. The spin-orbit excitons observed at 20-28 meV in both compounds strongly support the idea that Co2+ions of both compounds have a spin-orbital entangledJeff= 1/2 state. Furthermore, we found that a generalized Kitaev-Heisenberg Hamiltonian can describe the spin-wave excitations of both compounds with additional 3rd nearest-neighbor interaction. Our best-fit parameters show significant AFM Kitaev terms and off-diagonal symmetric anisotropy terms of a similar magnitude in both compounds. We also found a strong magnon-damping effect at the higher energy part of the spin waves, entirely consistent with observations in other Kitaev magnets. Our work suggests Na3Co2SbO6and Na2Co2TeO6as rare examples of the AFM Kitaev magnets based on the systematic studies of the spin waves and analysis.

Field-induced quantum spin disordered state in spin-1/2 honeycomb magnet Na2Co2TeO6.

Spin-orbit coupled honeycomb magnets with the Kitaev interaction have received a lot of attention due to their potential of hosting exotic quantum states including quantum spin liquids. Thus far, the most studied Kitaev systems are 4d/5d-based honeycomb magnets. Recent theoretical studies predicted that 3d-based honeycomb magnets, including Na2Co2TeO6 (NCTO), could also be a potential Kitaev system. Here, we have used a combination of heat capacity, magnetization, electron spin resonance measurements alongside inelastic neutron scattering (INS) to study NCTO's quantum magnetism, and we have found a field-induced spin disordered state in an applied magnetic field range of 7.5 T < B (⊥ b-axis) < 10.5 T. The INS spectra were also simulated to tentatively extract the exchange interactions. As a 3d-magnet with a field-induced disordered state on an effective spin-1/2 honeycomb lattice, NCTO expands the Kitaev model to 3d compounds, promoting further interests on the spin-orbital effect in quantum magnets.

Noncoplanar ferrimagnetism and local crystalline-electric-field anisotropy in the quasicrystal approximant Au70Si17Tb13.

Neutron scattering experiments have been performed to elucidate magnetic properties of the quasicrystal approximant Au70Si17Tb13, consisting of icosahedral spin clusters in a body-centered-cubic lattice. Bulk magnetic measurements performed on the single crystalline sample unambiguously confirm long-range ordering at T C = 11.6 ± 1 K. In contrast to the simple ferromagnetic response in the bulk measurements, single crystal neutron diffraction confirms a formation of intriguing non-collinear and non-coplanar magnetic order. The magnetic moment direction was found to be nearly tangential to the icosahedral cluster surface in the local mirror plane, which is quite similar to that recently found in the antiferromagnetic quasicrystal approximant Au72Al14Tb14. Inelastic neutron scattering on the powdered sample exhibits a very broad peak centered at ℏω ≃ 4 meV. The observed inelastic spectrum was explained by the crystalline-electric-field model taking account of the chemical disorder at the fractional Au/Si sites. The resulting averaged anisotropy axis for the crystalline-electric-field ground state is consistent with the ordered moment direction determined in the magnetic structure analysis, confirming that the non-coplanar magnetic order is stabilized by the local uniaxial anisotropy.

Gapless spin liquid in a square-kagome lattice antiferromagnet.

Observation of a quantum spin liquid (QSL) state is one of the most important goals in condensed-matter physics, as well as the development of new spintronic devices that support next-generation industries. The QSL in two dimensional quantum spin systems is expected to be due to geometrical magnetic frustration, and thus a kagome-based lattice is the most probable playground for QSL. Here, we report the first experimental results of the QSL state on a square-kagome quantum antiferromagnet, KCu6AlBiO4(SO4)5Cl. Comprehensive experimental studies via magnetic susceptibility, magnetisation, heat capacity, muon spin relaxation (µSR), and inelastic neutron scattering (INS) measurements reveal the formation of a gapless QSL at very low temperatures close to the ground state. The QSL behavior cannot be explained fully by a frustrated Heisenberg model with nearest-neighbor exchange interactions, providing a theoretical challenge to unveil the nature of the QSL state.

Regulatory T cells and liver pathology in a murine graft versus host response model.

AIM: We have previously reported in mice the hepatic inflammatory in graft versus host response (GVHR) model due to the disparity of major histocompatibility complex class-II. The regulatory T (Treg) cells have been reported to control excessive immune response and prevent immune-related diseases. This study aimed to investigate the pathogenesis profiles of chronic GVHR progression, focusing on the Treg cells. METHODS: GVHR mice induced by parental spleen CD4(+) T cell injection were sacrificed after 0, 2, 4, and 8 weeks (G0, G2, G4, G8). Further, one GVHR group received anti-IL-10 antibody in advance and were maintained for 2 weeks. Pathologic profiles of hepatic infiltrating inflammatory cells were evaluated by haematoxylin and eosin and immunohistochemistry staining with surface markers including Treg cell markers. RESULTS: Remarkable hepatic inflammatory in G2 significantly and gradually improved over time up to G8. In immunohistochemical staining, the increased IL-10 receptor beta(+) Tr1 cells in G2 were maintained through to G8; although other inflammatory cells decreased from G2 to G8. By contrast, in the anti-IL-10 antibody received-GVHR mice, the Tr1 cells were not detectable with significant inflammatory aggravation, while FoxP3(+) Treg cells significantly enhanced. CONCLUSIONS: These findings in the GVHR mice suggest that the expression and activity of Treg cells, especially the Tr1 cells, might be key factors for pathologic alteration in immune-related liver disease.

Novel excitations near quantum criticality in geometrically frustrated antiferromagnet CsFeCl3.

The investigation of materials that exhibit quantum phase transition provides valuable insights into fundamental problems in physics. We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder in the low-pressure phase and a noncollinear structure in the high-pressure phase. The neutron spectrum continuously evolves through critical pressure; a single mode in the disordered state becomes soft with the pressure and it splits into gapless and gapped modes in the ordered phase. Extended spin-wave theory reveals that the longitudinal and transverse fluctuations of spins are hybridized in the modes because of noncollinearity, and previously unidentified magnetic excitations are formed. We report a new hybridization of the phase and amplitude fluctuations of the order parameter near a quantum critical point in a spontaneously symmetry-broken state.

[Method for DNA extraction and purification from corn-processed food using an ion-exchange resin type kit].

The yield of genomic DNA extracted from corn-processed foods, such as corn flake and one of the corn snack what is called "Jumbo corn", using an ion-exchange resin type kit (Gtip) has been reported to be very low, and it is thought to be difficult to detect the intrinsic corn gene "Zein" in the foods. Therefore, we developed a new method using Gtip, which we called the "KNG-Gtip method," by modification of the Ministry of Health, Labour and Welfare (MHLW) method using Gtip (MHLW-Gtip method). We compared the KNG-Gtip method, MHLW-Gtip method, the Gtip method for detection of allergen (ALG-Gtip method), and the Gtip method according to the Ministry of Agriculture, Forestry and Fisheries (MAFF) (JAS-Gtip method) in terms of the yield and quality of genomic DNA and the detection probabilities of the PCR-amplified Zein gene. The concentrations of DNA and the detection probabilities of the PCR-amplified Zein gene of genomic DNA extracted from 4 g corn flake and 4 g Jumbo corn by the KNG-Gtip method were larger than those by using the conventional methods. In addition, the PCR-amplified Zein gene from 4 g of corn starch could be detected by the KNG-Gtip method. We propose that the KNG-Gtip method, in which requires sample weight of four grams, is practical and useful to extract genomic DNA from corn flake and Jumbo corn.

Essential role for the Menkes ATPase in activation of extracellular superoxide dismutase: implication for vascular oxidative stress.

Extracellular superoxide dismutase (SOD3), a secretory copper enzyme, plays an important role in atherosclerosis and hypertension by modulating the levels of extracellular superoxide anion (O2*-) in the vasculature. Little is known about the mechanisms by which SOD3 obtains its catalytic copper cofactor. Menkes ATPase (MNK) has been shown to transport cytosolic copper to the secretory pathway in nonvascular cells. We performed the present study to determine whether MNK is required for the activation of SOD3 in the vasculature. Here we show that MNK was highly expressed in the various vascular tissues and cells. Aortas and cultured fibroblasts from MNK mutant (MNK(mut)) mice showed a marked decrease in specific activity of SOD3, but not SOD1 (cytosolic form), which was partially restored by copper addition. Copper treatment in wild-type cells promoted the direct interaction and colocalization of SOD3 with MNK in the trans-Golgi network (TGN), suggesting that MNK transports copper to SOD3 in the TGN. Aortas of MNK(mut) mice revealed a decrease in activity of SOD3, but not SOD1, in association with a robust increase in O2*- levels. Finally, both MNK and SOD3 proteins were highly expressed in the intimal lesions of atherosclerotic vessels. In conclusion, vascular MNK plays an essential role in full activity of SOD3 through transporting copper to SOD3 in the TGN, thereby regulating O2*- levels in the vasculature. These studies provide a novel insight into vascular MNK as a critical modulator of "superoxide" stress, which may contribute to cardiovascular disease.

Role of antioxidant-1 in extracellular superoxide dismutase function and expression.

The extracellular superoxide dismutase (ecSOD or SOD3) is a copper-containing enzyme which is highly expressed in the vasculature. Copper-containing enzymes require copper chaperones for their activity however the chaperone which delivers copper to SOD3 has not previously been defined. Atox1 is a copper chaperone proposed to deliver copper to the trans-Golgi network. Because SOD3 is secreted via the trans-Golgi network, we sought to determine whether Atox1 acts as a copper chaperone for SOD3. Using recombinant human SOD3, we found that the specific activity of SOD3 directly correlates with its copper content (R2=0.99). SOD3 specific activity in the conditioned medium from cultured Atox1-/- fibroblasts was markedly decreased, but could be recovered to that of wild-type cells by copper addition. These results indicated that Atox1 is required for delivering copper to SOD3 for its full activity. Unexpectedly, the protein and mRNA levels of SOD3 were dramatically decreased in cultured Atox1-/- fibroblasts. This was associated with a marked decrease in SOD3 transcription rate but no change in SOD3 mRNA stability. Overexpression of Atox1 markedly increased SOD3 mRNA in both Atox1-/- and Atox1+/+ cells. These findings indicate that Atox1 positively regulates SOD3 transcription. Because SOD3 protein is upregulated in atherosclerotic vessels, we examined expression of Atox1 in vessels from ApoE-/- mice. Western and immunohistochemical analysis in ApoE-/- mice revealed that both Atox1 and SOD3 protein levels are markedly increased in atherosclerotic intimal lesions. In summary, Atox1 functions not only as a copper chaperone for SOD3 but also as a positive regulator for SOD3 transcription and may have an important role in modulating oxidative stress in the cardiovascular system.

Structure of the magnetic excitations in the spin-1/2 triangular-lattice Heisenberg antiferromagnet Ba3CoSb2O9.

A spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) is a prototypical frustrated quantum magnet, which exhibits remarkable quantum many-body effects that arise from the synergy between spin frustration and quantum fluctuation. The ground-state properties of a spin-1/2 TLHAF are theoretically well understood. However, the theoretical consensus regarding the magnetic excitations is limited. The experimental study of the magnetic excitations in spin-1/2 TLHAFs has also been limited. Here we show the structure of magnetic excitations in the spin-1/2 TLHAF Ba3CoSb2O9 investigated by inelastic neutron scattering. Significantly different from theoretical expectations, the excitation spectrum has a three-stage energy structure. The lowest-energy first stage is composed of dispersion branches of single-magnon excitations. The second and third stages are dispersive continua accompanied by a columnar continuum extending above 10 meV, which is six times larger than the exchange interaction J = 1.67 meV. Our results indicate the shortcomings of the current theoretical framework.Two-dimensional frustrated magnets are heavily studied because theories predict that quantum effects may lead to the emergence of fractionalized excitations. Ito et al. use inelastic neutron scattering to show that the excitation spectrum of Ba3CoSb2O9 disagrees with current theoretical expectations.

Large Magnetovolume Effect Induced by Embedding Ferromagnetic Clusters into Antiferromagnetic Matrix of Cobaltite Perovskite.

Materials that show negative thermal expansion (NTE) have significant industrial merit because they can be used to fabricate composites whose dimensions remain invariant upon heating. In some materials, NTE is concomitant with the spontaneous magnetization due to the magnetovolume effect (MVE). Here the authors report a new class of MVE material; namely, a layered perovskite PrBaCo2 O5.5+x (0 ≤ x ≤ 0.41), in which strong NTE [ß ≈ -3.6 × 10-5 K-1 (90-110 K) at x = 0.24] is triggered by embedding ferromagnetic (F) clusters into the antiferromagnetic (AF) matrix. The strongest MVE is found near the boundary between F and AF phases in the phase diagram, indicating the essential role of competition between the F-clusters and the AF-matrix. Furthermore, the MVE is not limited to the PrBaCo2 O5.5+x but is also observed in the NdBaCo2 O5.5+x . The present study provides a new approach to obtaining MVE and offers a path to the design of NTE materials.

Possible Tomonaga-Luttinger spin liquid state in the spin-1/2 inequilateral diamond-chain compound K3Cu3AlO2(SO4)4.

K3Cu3AlO2(SO4)4 is a highly one-dimensional spin-1/2 inequilateral diamond-chain antiferromagnet. Spinon continuum and spin-singlet dimer excitations are observed in the inelastic neutron scattering spectra, which is in excellent agreement with a theoretical prediction: a dimer-monomer composite structure, where the dimer is caused by strong antiferromagnetic (AFM) coupling and the monomer forms an almost isolated quantum AFM chain controlling low-energy excitations. Moreover, muon spin rotation/relaxation spectroscopy shows no long-range ordering down to 90 mK, which is roughly three orders of magnitude lower than the exchange interaction of the quantum AFM chain. K3Cu3AlO2(SO4)4 is, thus, regarded as a compound that exhibits a Tomonaga-Luttinger spin liquid behavior at low temperatures close to the ground state.

Fibulin-5 is a novel binding protein for extracellular superoxide dismutase.

The extracellular superoxide dismutase (ecSOD) plays an important role in atherosclerosis and endothelial function by modulating levels of the superoxide anion (O2*-) in the extracellular space. Although heparan sulfate proteoglycan is an important ligand for ecSOD, little is known about other biological binding partners of ecSOD. The goal of this study was to identify novel proteins that interact with ecSOD. A yeast two-hybrid screening of a human aorta cDNA library using ecSOD as bait identified fibulin-5 as a predominant binding protein for ecSOD. Further analysis showed that the binding domain of ecSOD within fibulin-5 mapped to its C-terminal domain. In vitro pulldown assays and coimmunoprecipitation analysis further confirmed that ecSOD interacts with fibulin-5 in vitro and in vivo. Studies using fibulin-5-/- mice indicated that fibulin-5 is required for binding of ecSOD to vascular tissue. Importantly, the decrease in tissue-bound ecSOD levels in aortas from fibulin-5-/- mice was associated with an increase in vascular O2*- levels. Furthermore, immunohistochemical analysis using ApoE-/- mice suggested a codistribution of ecSOD and fibulin-5 in atherosclerotic vessels. In summary, we provide in this study the first evidence that the ecSOD-fibulin-5 interaction is required for ecSOD binding to vascular tissues, thereby regulating vascular O2*- levels. This interaction may represent a novel mechanism for controlling vascular redox state in the extracellular space in various cardiovascular diseases such as atherosclerosis and hypertension in which oxidative stress is increased.

[Does early vascular access intervention therapy reduce acute obstruction and reconstruction of arterial-venous fistula?].

Acute vascular access (VA) obstruction is one of the most common complications for hemodialysis patients and medical professions. We performed early vascular access intervention therapy (VAIVT) to reduce the incidence of acute VA obstruction, VAIVT and fistula reconstruction. During a 2-year period, we performed 125 procedures of VAIVT in 145 cases in 50 patients who underwent arterio-venous fistula angiography. We performed early VAIVT within two weeks since we clinically found VA stenosis. The 125 procedures of VAIVT (95 non-thrombosed cases, 30 thrombosed cases) involved 86 native fistulas (74 non-thrombosed, 12 thrombosed) and 39 graft fistulas (21 non-thrombosed, 18 thrombosed). Prevalence of thrombosed cases was significantly higher in graft fistula than in native fistula (P<0.001). The primary patency rate in 50 patients at 6, 12 and 24 months was 62.1, 46.9 and 41.7%, respectively, while the secondary patency rate was 93.7, 90.7 and 86.6%, respectively. The highest primary patency rate was found in the non-thrombosed group with native fistula and the lowest secondary patency rate was found in the thrombosed group with graft fistula. By comparing the results of this study with the events for the previous 2 years, the total VAIVT number was almost the same. The number of non-thrombosed cases increased significantly from 54 to 95, and those of thrombosed cases decreased from 68 to 30 (P < 0.001). The number of fistula reconstructions significantly decreased from 59 to 22 (P<0.001). Early VAIVT for VA stenosis could decrease acute VA obstruction and fistula reconstruction without increasing the total number of VAIVT.