Turbulence Transition in Magnetically Confined Hydrogen and Deuterium Plasmas.

In this study, we discovered a turbulence transition in a large helical device. The turbulence level and turbulence-driven energy transport decrease to a specific transition density and increase above it. The ruling turbulences below and above the transition density were ion-temperature gradient (ITG) and resistive-interchange (RI) turbulences, consistent with the predictions of gyrokinetic theory and two-fluid MHD model, respectively. Isotope experiments on hydrogen (H) and deuterium (D) clarified the role of transitions. In the ITG regime, turbulence levels and energy transport were comparable in the H and D plasmas. In contrast, in the RI regime, they were clearly suppressed in the D plasma. The results provide crucial knowledge for understanding isotope effects and future optimization of stellarator and heliotron devices.

Field Induced Multiple Superconducting Phases in UTe_{2} along Hard Magnetic Axis.

The superconducting (SC) phase diagram in uranium ditelluride is explored under magnetic fields (H) along the hard magnetic b axis using a high-quality single crystal with T_{c}=2.1 K. Simultaneous electrical resistivity and ac magnetic susceptibility measurements discern low- and high-field SC (LFSC and HFSC, respectively) phases with contrasting field-angular dependence. Crystal quality increases the upper critical field of the LFSC phase, but the H^{*} of ∼15 T, at which the HFSC phase appears, is always the same through the various crystals. A phase boundary signature is also observed inside the LFSC phase near H^{*}, indicating an intermediate SC phase characterized by small flux pinning forces.

Longitudinal Spin Fluctuations Driving Field-Reinforced Superconductivity in UTe_{2}.

Our measurements of ^{125}Te NMR relaxations reveal an enhancement of electronic spin fluctuations above µ_{0}H^{*}∼15 T, leading to their divergence in the vicinity of the metamagnetic transition at µ_{0}H_{m}≈35 T, below which field-reinforced superconductivity appears when a magnetic field (H) is applied along the crystallographic b axis. The NMR data evidence that these fluctuations are dominantly longitudinal, providing a key to understanding the peculiar superconducting phase diagram in H∥b, where such fluctuations enhance the pairing interactions.

Dual-Task Training Combining Cognitive Tasks and Occupations among Japanese Community-Dwelling Older Adults: A Pilot Study.

This study investigated whether dual tasks comprising cognitive tasks and occupations related to daily living can improve the mental and cognitive function of Japanese community-dwelling older adults. Participants included 30 older adults, equally divided into intervention and control groups. The outcome measures were memory, attention, depression, and health-related quality of life. No adverse effects of the intervention were observed in any participant in the intervention group. Logical memory I, logical memory II, and Center for Epidemiologic Studies Depression Scale scores showed a significant interaction. Dual tasks combining cognitive tasks and occupations may help improve delayed recall and alleviate depression. A novel attempt to integrate cognitive stimulation and activities valued by individuals may help mediate age-related cognitive function decline and reduce depressive symptoms in community-dwelling older adults.

Whole-Genome Sequencing of the NARO World Rice Core Collection (WRC) as the Basis for Diversity and Association Studies.

Genebanks provide access to diverse materials for crop improvement. To utilize and evaluate them effectively, core collections, such as the World Rice Core Collection (WRC) in the Genebank at the National Agriculture and Food Research Organization, have been developed. Because the WRC consists of 69 accessions with a high degree of genetic diversity, it has been used for >300 projects. To allow deeper investigation of existing WRC data and to further promote research using Genebank rice accessions, we performed whole-genome resequencing of these 69 accessions, examining their sequence variation by mapping against the Oryza sativa ssp. japonica Nipponbare genome. We obtained a total of 2,805,329 single nucleotide polymorphisms (SNPs) and 357,639 insertion-deletions. Based on the principal component analysis and population structure analysis of these data, the WRC can be classified into three major groups. We applied TASUKE, a multiple genome browser to visualize the different WRC genome sequences, and classified haplotype groups of genes affecting seed characteristics and heading date. TASUKE thus provides access to WRC genotypes as a tool for reverse genetics. We examined the suitability of the compact WRC population for genome-wide association studies (GWASs). Heading date, affected by a large number of quantitative trait loci (QTLs), was not associated with known genes, but several seed-related phenotypes were associated with known genes. Thus, for QTLs of strong effect, the compact WRC performed well in GWAS. This information enables us to understand genetic diversity in 37,000 rice accessions maintained in the Genebank and to find genes associated with different phenotypes. The sequence data have been deposited in DNA Data Bank of Japan Sequence Read Archive (DRA) (Supplementary Table S1).

Study of Quasielastic Barrier Distributions as a Step towards the Synthesis of Superheavy Elements with Hot Fusion Reactions.

The excitation functions for quasielastic scattering of ^{22}Ne+^{248}Cm, ^{26}Mg+^{248}Cm, and ^{48}Ca+^{238}U are measured using a gas-filled recoil ion separator. The quasielastic barrier distributions are extracted for these systems and are compared with coupled-channel calculations. The results indicate that the barrier distribution is affected dominantly by deformation of the actinide target nuclei, but also by vibrational or rotational excitations of the projectile nuclei, as well as neutron transfer processes before capture. From a comparison between the experimental barrier distributions and the evaporation residue cross sections for Sg (Z=106), Hs (108), Cn (112), and Lv (116), it is suggested that the hot fusion reactions take advantage of a compact collision, where the projectile approaches along the short axis of a prolately deformed nucleus. A new method is proposed to estimate the optimum incident energy to synthesize unknown superheavy nuclei using the barrier distribution.

Mapping of a New Deformation Region around

We performed the first direct mass measurements of neutron-rich scandium, titanium, and vanadium isotopes around the neutron number 40 at the RIKEN RI Beam Factory using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{58-60}Sc, ^{60-62}Ti, and ^{62-64}V were measured for the first time. The experimental results show that the two-neutron separation energies in the vicinity of ^{62}Ti increase compared to neighboring nuclei. This shows that the masses of Ti isotopes near N=40 are affected by the Jahn-Teller effect. Therefore, a development of Jahn-Teller stabilization appears below the Cr isotopes, and the systematics in Sc, Ti, and V isotopes suggest that ^{62}Ti is located close to the peak of the Jahn-Teller effect.

How Different is the Core of

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

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.

Evidence for Spin Singlet Pairing with Strong Uniaxial Anisotropy in URu_{2}Si_{2} Using Nuclear Magnetic Resonance.

In order to identify the spin contribution to superconducting pairing compatible with the so-called "hidden order", ^{29}Si nuclear magnetic resonance measurements have been performed using a high-quality single crystal of URu_{2}Si_{2}. A clear reduction of the ^{29}Si Knight shift in the superconducting state has been observed under a magnetic field applied along the crystalline c axis, corresponding to the magnetic easy axis. These results provide direct evidence for the formation of spin-singlet Cooper pairs. Consequently, results indicating a very tiny change of the in-plane Knight shift reported previously demonstrate extreme uniaxial anisotropy for the spin susceptibility in the hidden order state.

Excitation of the Isovector Spin Monopole Resonance via the Exothermic

The (^{12}N, ^{12}C) charge-exchange reaction at 175 MeV/u was developed as a novel probe for studying the isovector spin giant monopole resonance (IVSMR), whose properties are important for better understanding the bulk properties of nuclei and asymmetric nuclear matter. This probe, now available through the production of ^{12}N as a secondary rare-isotope beam, is exothermic, is strongly absorbed at the surface of the target nucleus, and provides selectivity for spin-transfer excitations. All three properties enhance the excitation of the IVSMR compared to other, primarily light-ion, probes, which have been used to study the IVSMR thus far. The ^{90}Zr(^{12}N,^{12}C) reaction was measured and the excitation energy spectra up to about 70 MeV for both the spin-transfer and non-spin-transfer channels were deduced separately by tagging the decay by γ emission from the ^{12}C ejectile. Besides the well-known Gamow-Teller and isobaric analog transitions, a clear signature of the IVSMR was identified. By comparing with the results from light-ion reactions on the same target nucleus and theoretical predictions, the suitability of this new probe for studying the IVSMR was confirmed.

Extraction of the Landau-Migdal Parameter from the Gamow-Teller Giant Resonance in

The key parameter to discuss the possibility of the pion condensation in nuclear matter, i.e., the so-called Landau-Migdal parameter g^{'}, was extracted by measuring the double-differential cross sections for the (p,n) reaction at 216 MeV/u on a neutron-rich doubly magic unstable nucleus, ^{132}Sn with the quality comparable to data taken with stable nuclei. The extracted strengths for Gamow-Teller (GT) transitions from ^{132}Sn leading to ^{132}Sb exhibit the GT giant resonance (GTR) at the excitation energy of 16.3±0.4(stat)±0.4(syst) MeV with the width of Γ=4.7±0.8 MeV. The integrated GT strength up to E_{x}=25 MeV is S_{GT}^{-}=53±5(stat)_{-10}^{+11}(syst), corresponding to 56% of Ikeda's sum rule of 3(N-Z)=96. The present result accurately constrains the Landau-Migdal parameter as g^{'}=0.68±0.07, thanks to the high sensitivity of the GTR energy to g^{'}. In combination with previous studies on the GTR for ^{90}Zr and ^{208}Pb, the result of this work shows the constancy of this parameter in the nuclear chart region with (N-Z)/A=0.11 to 0.24 and A=90 to 208.

Magic Nature of Neutrons in

We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.

Observation of the Isovector Giant Monopole Resonance via the

The (^{10}Be,^{10}B^{*}[1.74 MeV]) charge-exchange reaction at 100 AMeV is presented as a new probe for isolating the isovector (ΔT=1) nonspin-transfer (ΔS=0) response of nuclei, with ^{28}Si being the first nucleus studied. By using a secondary ^{10}Be beam produced by fast fragmentation of ^{18}O nuclei at the NSCL Coupled Cyclotron Facility, applying the dispersion-matching technique with the S800 magnetic spectrometer to determine the excitation energy in ^{28}Al, and performing high-resolution γ-ray tracking with the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) to identify the 1022-keV γ ray associated with the decay from the 1.74-MeV T=1 isobaric analog state in ^{10}B, a ΔS=0 excitation-energy spectrum in ^{28}Al was extracted. Monopole and dipole contributions were determined through a multipole-decomposition analysis, and the isovector giant dipole resonance and isovector giant monopole resonance (IVGMR) were identified. The results show that this probe is a powerful tool for studying the elusive IVGMR, which is of interest for performing stringent tests of modern density functional theories at high excitation energies and for constraining the bulk properties of nuclei and nuclear matter. The extracted distributions were compared with theoretical calculations based on the normal-modes formalism and the proton-neutron relativistic time-blocking approximation. Calculated cross sections based on these strengths underestimate the data by about a factor of 2, which likely indicates deficiencies in the reaction calculations based on the distorted wave Born approximation.

Risk factors for severe dysphagia in acute cervical spinal cord injury.

STUDY DESIGN: A retrospective, consecutive case series. OBJECTIVES: The relationship between dysphagia and acute cervical spinal cord injury (CSCI) has been recently reported; however, the cause and mechanism of dysphagia are still not well understood. No definitive factors have yet been established according to multivariate analysis. The objective is to elucidate the incidence and risk factors of dysphagia in patients with acute CSCI. SETTING: Spinal Injuries Center, Fukuoka, Japan. METHODS: A total of 298 patients with acute CSCI, who were evaluated for neurological impairment within 3 days after injury, were reviewed. CSCI patients with tube dependence due to obvious aspiration after injury were defined as having dysphagia. The factors postulated to increase the risk for dysphagia, including the patient's age, sex, American Spinal Injury Association (ASIA) impairment scale at 3 days after injury, level of injury, tracheostomy and operative treatment, were analyzed using a multiple logistic regression model. RESULTS: Of 298 patients, 21 were suffering from severe dysphagia after acute CSCI (7.0%). Of these 21 patients, 12 (57%) had CSCI at the C3-C4 level. Multivariable logistic regression analysis revealed that old age (>72 years), severe ASIA impairment scale (A or B) and presence of tracheostomy were significant risk factors of dysphagia. Level of injury ⩾C3-C4 was not a significant risk factor after adjustment for several potential confounders. CONCLUSION: The incidence of severe dysphagia associated with aspiration was 7%. Old age, severe paralysis and presence of tracheostomy may be the risk factors for dysphagia. The risk for dysphagia should be evaluated to prevent aspiration pneumonia.

A radiographic evaluation of facet sagittal angle in cervical spinal cord injury without major fracture or dislocation.

STUDY DESIGN: A retrospective radiographic study with a minimum 2-year follow-up. OBJECTIVE: To evaluate the relationships between the cervical articular facets' morphology and the incidence of traumatic cervical spinal cord injury (CSCI) without major fracture or dislocation. SETTING: Spinal Injuries Center, Japan. METHODS: This study included 113 patients with traumatic CSCI without major fracture or dislocation. Eighty-four healthy volunteers without neurological deficits or cervical cord pathology on magnetic resonance imaging (MRI) were defined as control subjects. We used a plain sagittal radiograph to measure the facet sagittal angles (FSA) at four cervical segments in all the CSCI patients and controls. We defined the FSA as the angle between the inferior margin of the superior cervical spinal body and the inferior articular process of the superior vertebra. RESULTS: Most frequent incidence of CSCI was seen at C3-4 segment (54%). With respect to CSCI at C3-4 segment, 55.7% of the subjects showed smallest FSA at C3-4 segment. CONCLUSION: Most of the traumatic CSCI at C3-4 segment showed raised cervical articular facets at C3-4 segment. On the basis of our results, we hypothesized that the raised cervical articular facets might have an important role in the etiology of traumatic CSCI. The cervical spinal cord at the C3-4 segment might receive the highest load during acute hyperextension of the cervical spine because of the C3-4 articular facets' morphology.

Candidate Resonant Tetraneutron State Populated by the

A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186 MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst) MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be) reaction, an almost recoilless condition of the four-neutron system was achieved so as to obtain a weakly interacting four-neutron system efficiently.

Development of polymorphic microsatellite loci in Odontobutis obscura using Illumina paired-end sequencing and the test of cross-species amplification.

Odontobutis obscura is a bottom-dwelling freshwater fish native to East Asia. Its range encompasses southwest China, western Japan, and Geoje Island in South Korea. Despite its widespread range in China and Japan, only a small and spatially isolated population is found in South Korea. We developed a total of 23 novel and polymorphic microsatellite loci of O. obscura using Illumina paired-end shotgun sequencing and characterized them using 80 Japanese and Korean samples. An extensive genetic polymorphism was detected at these 23 loci, with the observed number of alleles at a locus ranging from 2 to 15 and expected and observed heterozygosities ranging from 0 to 0.656 and 0 to 0.547, respectively. Korean O. obscura exhibited a much lower level of genetic variability than the Japanese population did, probably as a result of long-term isolation combined with historical bottlenecks. The Japanese and Korean populations showed a high level of genetic differentiation with FST = 0.700 and RST = 0.913. Many of our primer sets were successfully transferable to congeneric O. interrupta and O. platycephala, which exhibited even greater polymorphism than Korean O. obscura. In conclusion, our study showed that these 23 microsatellite markers are useful for understanding the conservation biology and population genetic structure of O. obscura and other congeneric species.

Phase I/II study of S-1 in combination with sorafenib for metastatic renal cell carcinoma.

BACKGROUND: The potential of S-1 for the treatment of metastatic renal cell carcinoma (mRCC) has been shown in two phase II studies. We aimed to assess the safety, tolerance, pharmacokinetics and clinical activity of S-1 combined with sorafenib in patients with mRCC. PATIENTS AND METHODS: In this multicenter, single-arm, open-label, phase I/II study of S-1 plus sorafenib, we recruited patients with clear-cell or papillary renal cell carcinoma who had received a maximum of one prior cytokine-based regimen. The phase I primary end points were the maximum tolerated dose (MTD) and recommended dose (RD). S-1 was administered orally at 60, 80, 100 or 120 mg/day on days 1-28 of a 42-day cycle in combination with sorafenib (400 or 800 mg/day), given daily with dose adjustment. In phase II, the primary end point was to assess the overall response rate (ORR) at the RD. RESULTS: Nine patients were enrolled into phase I and 21 (including 6 patients who received the RD in the phase I portion) were enrolled into phase II. In the phase I portion, the MTD could not be determined, and the RD was defined as S-1 80 mg/m(2)/day on days 1-28 + sorafenib 800 mg/day on days 1-42. In the phase II portion, 21 patients were fully assessable for efficacy and safety. The confirmed ORR was 52% [95% confidence interval (CI) 29.8-74.3], including one complete response (5%) and 10 partial responses (48%). The median progression-free survival was 9.9 (95% CI 6.5-17.1) months. The most frequently reported treatment-related adverse event for all grades was hand-foot skin reaction (100%). The major reasons for dose reduction were hand-foot skin reaction (38%) and rash (14%). CONCLUSION: Combination therapy with S-1 plus sorafenib is effective and tolerable for patients with mRCC. However, skin events management is important in S-1 plus sorafenib combination therapy.