Magnetoconduction in the Correlated Semiconductor FeSi in Ultrastrong Magnetic Fields up to a Semiconductor-to-Metal Transition.

Magnetoresistance of the correlated narrow-gap semiconductor FeSi was investigated by the radio frequency self-resonant spiral coil technique in magnetic fields up to 500 T, which is supplied by an electromagnetic flux compression megagauss generator. Semiconductor-to-metal transition accomplishes around 270 T observed as a sharp kink in the magnetoresistance, which implies the closing of the hybridization gap by the Zeeman shift of band edges. In the temperature-magnetic field phase diagram, the semiconductor-metal transition field is found to be almost independent of temperature, which is in contrast to a characteristic magnetic field associated with the hopping magnetoconduction in the in-gap localized states, exhibiting a notable temperature dependence.

Large Enhancement of Thermoelectric Efficiency Due to a Pressure-Induced Lifshitz Transition in SnSe.

The Lifshitz transition, a change in Fermi surface topology, is likely to greatly influence exotic correlated phenomena in solids, such as high-temperature superconductivity and complex magnetism. However, since the observation of Fermi surfaces is generally difficult in the strongly correlated systems, a direct link between the Lifshitz transition and quantum phenomena has been elusive so far. Here, we report a marked impact of the pressure-induced Lifshitz transition on thermoelectric performance for SnSe, a promising thermoelectric material without a strong electron correlation. By applying pressure up to 1.6 GPa, we have observed a large enhancement of the thermoelectric power factor by more than 100% over a wide temperature range (10-300 K). Furthermore, the high carrier mobility enables the detection of quantum oscillations of resistivity, revealing the emergence of new Fermi pockets at ∼0.86 GPa. The observed thermoelectric properties linked to the multivalley band structure are quantitatively reproduced by first-principles calculations, providing novel insight into designing the SnSe-related materials for potential valleytronic as well as thermoelectric applications.

A series of magnon crystals appearing under ultrahigh magnetic fields in a kagomé antiferromagnet.

Geometrical frustration and a high magnetic field are two key factors for realizing unconventional quantum states in magnetic materials. Specifically, conventional magnetic order can potentially be destroyed by competing interactions and may be replaced by an exotic state that is characterized in terms of quasiparticles called magnons, the density and chemical potential of which are controlled by the magnetic field. Here we show that a synthetic copper mineral, Cd-kapellasite, which comprises a kagomé lattice consisting of corner-sharing triangles of spin-1/2 Cu2+ ions, exhibits an unprecedented series of fractional magnetization plateaus in ultrahigh magnetic fields of up to 160 T. We propose that these quantum states can be interpreted as crystallizations of emergent magnons localized on the hexagon of the kagomé lattice.

Topological transitions among skyrmion- and hedgehog-lattice states in cubic chiral magnets.

Manipulating topological spin textures is a key for exploring unprecedented emergent electromagnetic phenomena. Whereas switching control of magnetic skyrmions, e.g., the transitions between a skyrmion-lattice phase and conventional magnetic orders, is intensively studied towards development of future memory device concepts, transitions among spin textures with different topological orders remain largely unexplored. Here we develop a series of chiral magnets MnSi1-xGex, serving as a platform for transitions among skyrmion- and hedgehog-lattice states. By neutron scattering, Lorentz transmission electron microscopy and high-field transport measurements, we observe three different topological spin textures with variation of the lattice constant controlled by Si/Ge substitution: two-dimensional skyrmion lattice in x = 0-0.25 and two distinct three-dimensional hedgehog lattices in x = 0.3-0.6 and x = 0.7-1. The emergence of various topological spin states in the chemical-pressure-controlled materials suggests a new route for direct manipulation of the spin-texture topology by facile mechanical methods.

Large magneto-thermopower in MnGe with topological spin texture.

Quantum states characterized by nontrivial topology produce interesting electrodynamics and versatile electronic functionalities. One source for such remarkable phenomena is emergent electromagnetic field, which is the outcome of interplay between topological spin structures with scalar spin chirality and conduction electrons. However, it has scarcely been exploited for emergent function related to heat-electricity conversion. Here we report an unusually enhanced thermopower by application of magnetic field in MnGe hosting topological spin textures. By considering all conceivable origins through quantitative investigations of electronic structures and properties, a possible origin of large magneto-thermopower is assigned to the strong energy dependence of charge-transport lifetime caused by unconventional carrier scattering via the dynamics of emergent magnetic field. Furthermore, high-magnetic-field measurements corroborate the presence of residual magnetic fluctuations even in the nominally ferromagnetic region, leading to a subsisting behavior of field-enhanced thermopower. The present finding may pave a way for thermoelectric function of topological magnets.

Characteristics of neuropathic pain and its relationship with quality of life in 72 patients with spinal cord injury.

STUDY DESIGN: A cross-sectional study. OBJECTIVES: Neuropathic pain (NP) after spinal cord injury (SCI) tends to be hard to treat, and its heterogeneous properties make it difficult to identify and characterize. This study was conducted to assess the characteristics of SCI-related NP in detail. SETTING: A single hospital for SCI rehabilitation. METHODS: This study included 72 patients who were seen at our hospital in 2012 and 2013 and who had sustained SCI at least 3 months before enrollment. The patients completed the Neuropathic Pain Symptom Inventory (NPSI) and the Short Form (SF)-36 Health Inventory. The NPSI score was analyzed for correlations with clinical presentations of SCI and SF-36 subitems. RESULTS: Paresthesia/dysesthesia was the most common subtype of NP after SCI. With regard to location, below-level superficial NP was significantly more intense than at-level pain. Patients who underwent surgery showed significantly less evoked pain compared with patients with non-surgery. Patients reported significantly more severe pain if >1 year had elapsed after the SCI. Patients with an American Spinal Injury Association Impairment Scale grade of B for completeness of injury reported more intense NP than those with other grades. Among the SF-36 subitems, NP correlated significantly with bodily pain, general health and mental health. CONCLUSION: NP in SCI patients was significantly associated with the location of pain, the time period since the injury, surgery and quality-of-life factors. A more detailed understanding of the characteristics of NP may contribute to better strategies for relieving the pain associated with SCI.

One-Third Magnetization Plateau with a Preceding Novel Phase in Volborthite.

We have synthesized high-quality single crystals of volborthite, a seemingly distorted kagome antiferromagnet, and carried out high-field magnetization measurements up to 74 T and ^{51}V NMR measurements up to 30 T. An extremely wide 1/3 magnetization plateau appears above 28 T and continues over 74 T at 1.4 K, which has not been observed in previous studies using polycrystalline samples. NMR spectra reveal an incommensurate order (most likely a spin-density wave order) below 22 T and a simple spin structure in the plateau phase. Moreover, a novel intermediate phase is found between 23 and 26 T, where the magnetization varies linearly with magnetic field and the NMR spectra indicate an inhomogeneous distribution of the internal magnetic field. This sequence of phases in volborthite bears a striking similarity to those of frustrated spin chains with a ferromagnetic nearest-neighbor coupling J_{1} competing with an antiferromagnetic next-nearest-neighbor coupling J_{2}.

Magnetic control of transverse electric polarization in BiFeO3.

Numerous attempts have been made to realize crossed coupling between ferroelectricity and magnetism in multiferroic materials at room temperature. BiFeO3 is the most extensively studied multiferroic material that shows multiferroicity at temperatures significantly above room temperature. Here we present high-field experiments on high-quality mono-domain BiFeO3 crystals reveal substantial electric polarization orthogonal to the widely recognized one along the trigonal c axis. This novel polarization appears to couple with the domains of the cycloidal spin order and, hence, can be controlled using magnetic fields. The transverse polarization shows the non-volatile memory effect at least up to 300 K.

Field re-entrant hidden-order phase under pressure in URu2Si2.

We succeeded in growing high quality single crystals of URu(2)Si(2) and performed thermal expansion measurements under pressure. Applying a magnetic field along the [001] direction in the tetragonal structure, the so-called hidden-order phase reappears after the suppression of the antiferromagnetic phase above the critical pressure P(x). We determined the pressure-temperature-field phase diagram for the paramagnetic, hidden-order and antiferromagnetic states for the [Formula: see text] direction. We also present the temperature dependence of the upper critical field H(c2) for [Formula: see text] and [100] determined by the AC specific heat measurements, corresponding to the bulk superconductivity in a high quality single crystal.

Quantum computation in correlation space and extremal entanglement.

Recently, a framework was established to systematically construct novel universal resource states for measurement-based quantum computation using techniques involving finitely correlated states. With these methods, universal states were found which are in certain ways much less entangled than the original cluster-state model, and it was hence believed that with this approach, many of the extremal entanglement features of the cluster states could be relaxed. The new resources were constructed as "computationally universal" states-i.e., they allow one to efficiently reproduce the classical output of each quantum computation-whereas the cluster states are universal in a stronger sense since they are "universal state preparators." Here, we show that the new resources are universal state preparators after all, and must therefore exhibit a whole class of extremal entanglement features, similar to the cluster states.

Computerized quantification of psoriasis lesions with colour calibration: preliminary results.

An evaluation was made of a fully automated index of psoriasis, termed Computer-assisted Area and Severity Index (CASI). This method requires taking digital photographs of the target skin area(s) with a colour reference marker, Casmatch. The CASI evaluates the severity of the psoriasis from the size and redness of the lesion(s). In five patients with mild psoriasis vulgaris mainly observed on their trunk, 18 photographs of the trunk were taken every 2 weeks. Three of the five patients [Psoriasis Area and Severity Index (PASI) of 3.0, 3.6 and 10.1, respectively] were treated with oral cyclosporin 3 mg/kg/day for 4 weeks. The mean +/- SD area of lesion selected by a dermatologist was 2.3 +/- 1.3% of the total skin area. This method achieved extraction performance for psoriasis of 72.1 +/- 19.4% for sensitivity and 97.4 +/- 2.0% for specificity. CASI correlated strongly with PASI (r = 0.92), but not with Skindex16 (r = 0.35). Although only erythema was evaluated, our preliminary results indicate that this method is capable of quantifying psoriasis lesions.

Protective effects of nef-deleted SHIV or that having IFN-gamma against disease induced with a pathogenic virus early after vaccination.

To clarify the involvement of primitive non-specific immune responses in the protective effects of a live, attenuated virus, each two rhesus macaques were intravenously immunized with an attenuated chimeric simian and human immunodeficiency virus (SHIV) in which the nef gene was deleted (SHIV-NI) or a SHIV having human IFN-gamma inserted into the deleted nef region (SHIV IFN-gamma). These immunized monkeys were intravenously challenged with a heterologous pathogenic SHIV (SHIV-C2/1) at four weeks post immunization (wpi). After vaccination, one of each SHIV-NI- or SHIV IFN-gamma-immunized monkeys showed a low level of SIV Gag-specific lymphocyte proliferative response but did not have neutralizing antibodies to both the parental and challenge viruses. After the challenge, the plasma viral RNA loads of the challenge virus were suppressed in all the immunized monkeys and the severe CD4+ T cell loss observed in the unimmunized monkeys was not found. Thus, both SHIV IFN-gamma and SHIV-NI infections could prevent from disease progression by a pathogenic virus early after immunization, suggesting that primitive non-specific immune response elicited by attenuated virus infection, in addition to highly acquired virus-specific immunity, contributes to the protective effect against a pathogenic virus.

Homing receptor and chemokine receptor on intraepidermal T cells in psoriasis vulgaris.

Intraepidermal T lymphocytes found in psoriatic skin lesions are involved in the development and maintenance of lesional pathology. It has become clear that differential expression of homing and chemokine receptors determines the specific migration of T cells to distinct tissues and microenvironments, including psoriasis lesions. The aim of the present study was to clarify expression of homing (CLA, VLA-4, and LFA-1) and chemokine (CCR4, CCR6, CCR7, and CXCR3) receptors on intraepidermal T cells in psoriatic lesions using flow cytometry. The vast majority of intraepidermal T cells in psoriatic lesions expressed CLA and LFA-1, whereas 58% of CD4+ and 85% of CD8+ T cells expressed VLA-4. The majority of CD4+ T cells and about half of the CD8+ T cells expressed CCR4 and CCR6, whereas less than one-third of CD4+ and CD8+ T cells expressed CXCR3 or CCR7. In patients with psoriasis the percentages of T cells expressing CLA, CCR4, and CCR6 were much higher in the epidermis of psoriatic plaques than in the peripheral blood. Thus, CLA, CCR4, and CCR6 may play a more important role in the migration of T cells to psoriatic epidermis.

The quantity and diversity of infectious viruses in various tissues of SHIV-infected monkeys at the early and AIDS stages.

To detect the major sites of viral replication in immunodeficiency virus-infected individuals, we quantified proviral DNA and infectious viruses using quantitative PCR and a plaque assay, respectively, in various tissues of SHIV(KU-2)-infected monkeys in the early and AIDS stages of infection. Compared the quantity of infectious virus among PBMC and the lymphoid tissues, the mesenteric lymph node had the largest number of infectious viruses at the AIDS stage more than at the early stage of infection. These results suggested that the gastrointestinal tract was a major site of viral replication. In the brain, proviral DNA was detected at the early and AIDS stage of infection, but infectious viruses were detected at only the AIDS stage. Moreover, we analyzed the nucleotide sequences of the env V3 region in infectious virus clones isolated from each plaque. The viruses in the lymphoid tissues of the monkey that developed AIDS diverged from the inoculated virus and had the same three amino acid substitutions. However, the viruses in the brain were almost identical to the inoculated virus, suggesting that the virus entered the brain early after infection and persisted without replication and genetic diversion until the AIDS stage.

Response to ADP-ribose by activation of TRPM2 in the CRI-G1 insulinoma cell line.

The response to intracellular ADP-ribose in the rat CRI-G1 insulinoma cell line was studied using a patch-clamp method. Dialysis of ADP-ribose into cells induced a response in a dose-dependent manner. The reversal potentials in various solutions showed that the ADP-ribose-gated channel was a Ca2+-permeable nonselective cation channel. In inside-out recordings, ADP-ribose and b-NAD induced responses in the same patch. The single-channel current-voltage relationships for ADP-ribose- and b-NAD-induced responses were almost identical, indicating that ADP-ribose and b-NAD activated the same channel. The physiological properties of the ADP-ribose-gated channel are similar to those we reported previously for the cloned transient receptor potential channel TRPM2. Moreover, RT-PCR analysis showed that TRPM2 was abundantly expressed in CRI-G1 cells, suggesting that the ADP-ribose-gated channel represents the native TRPM2 channel in CRI-G1 cells. These results suggest that ADP-ribose can be an endogenous modulator of Ca2+ influx through the TRPM2 channel into CRI-G1 cells.

Genetics of cognition: outline of a collaborative twin study.

A multidisciplinary collaborative study examining cognition in a large sample of twins is outlined. A common experimental protocol and design is used in The Netherlands, Australia and Japan to measure cognitive ability using traditional IQ measures (i.e., psychometric IQ), processing speed (e.g., reaction time [RT] and inspection time [IT]), and working memory (e.g., spatial span, delayed response [DR] performance). The main aim is to investigate the genetic covariation among these cognitive phenotypes in order to use the correlated biological markers in future linkage and association analyses to detect quantitative-trait loci (QTLs). We outline the study and methodology, and report results from our preliminary analyses that examines the heritability of processing speed and working memory indices, and their phenotypic correlation with IQ. Heritability of Full Scale IQ was 87% in the Netherlands, 83% in Australia, and 71% in Japan. Heritability estimates for processing speed and working memory indices ranged from 33-64%. Associations of IQ with RT and IT (-0.28 to -0.36) replicated previous findings with those of higher cognitive ability showing faster speed of processing. Similarly, significant correlations were indicated between IQ and the spatial span working memory task (storage [0.31], executive processing [0.37]) and the DR working memory task (0.25), with those of higher cognitive ability showing better memory performance. These analyses establish the heritability of the processing speed and working memory measures to be used in our collaborative twin study of cognition, and support the findings that individual differences in processing speed and working memory may underlie individual differences in psychometric IQ.

Field dependence-independence from a working memory perspective: a dual-task investigation of the Hidden Figures test.

Field dependence-independence (FDI) is a construct intensively investigated within cognitive style research, but its cognitive underpinnings are not clearly specified. We propose that performance on FDI tasks primarily reflects the operations of the visuospatial and executive components of working memory. We tested this hypothesis in a dual-task experiment with a commonly used measure of FDI, the Hidden Figures Test. The results showed that performance on this test was impaired by concurrent performance of secondary tasks that primarily tap the visuospatial component (spatial tapping) and the executive component (2-back and random number generation), but was almost unaffected by other secondary tasks (simple tapping and articulatory suppression). Moreover, an analysis of secondary task performance ruled out the possibility of strategic trade-offs and revealed an intriguing dissociation for two different sets of "randomness" indices for the random number generation task. These results support the hypothesised mapping between FDI and working memory components and suggest that the dual-task paradigm can provide a useful way to bring underspecified constructs like FDI into closer alignment with theoretical ideas developed within cognitive psychology.

Immunocyte Ca2+ influx system mediated by LTRPC2.

We characterized an activation mechanism of the human LTRPC2 protein, a member of the transient receptor potential family of ion channels, and demonstrated that LTRPC2 mediates Ca2+ influx into immunocytes. Intracellular pyrimidine nucleotides, adenosine 5'-diphosphoribose (ADPR), and nicotinamide adenine dinucleotide (NAD), directly activated LTRPC2, which functioned as a Ca2+-permeable nonselective cation channel and enabled Ca2+ influx into cells. This activation was suppressed by intracellular adenosine triphosphate. These results reveal that ADPR and NAD act as intracellular messengers and may have an important role in Ca2+ influx by activating LTRPC2 in immunocytes.