Search

The mixed-anion compounds Sn2SbS2−xSexI3 (x = 0, 0.2, 0.5) and Sn2BiS2I3 were synthesized and ultralow thermal conductiviy was found for the mixed-anion solid solution.

Background: Immune-related sclerosing cholangitis (irSC) is relatively rare and its clinical characteristics are not well known. In this study, we aimed to summarize the clinical features of irSC. Methods: Clinical data were collected retrospectively from 1,393 patients with advanced malignancy treated with immune-checkpoint inhibitors (ICIs) between August 2014 and October 2021. We analyzed patients with immune-related adverse events of liver injury (liver-irAEs) and compared irSC and non-irSC groups. Results: Sixty-seven patients (4.8%) had a liver-irAE (≥ grade 3) during the follow-up period (median, 262 days). Among these, irSC was observed in eight patients (11.9%). All patients in the irSC group were treated with anti-PD-1/PD-L1 antibodies. Compared with the non-irSC group, the irSC group showed mainly non-hepatocellular liver injury (87.5 % vs 50.8 %, P = 0.065), and had elevated serum inflammatory markers (e.g., CRP and NLR) and biliary enzymes (e.g., GGTP and ALP) at the onset of liver-irAEs. Furthermore, most patients with irSC had abdominal pain. In the non-irSC group, the liver injury of 23 patients improved only with the discontinuation of ICIs, and 22 patients improved with medication including prednisolone (PSL). Conversely, almost all patients (n=7) in the irSC group were treated with PSL, but only two patients experienced an improvement in liver injury. Conclusion: We found that irSC is characterized by a non-hepatocellular type of liver injury with abdominal pain and a high inflammatory response and is refractory to treatment. Further examination by imaging is recommended to detect intractable irSC in cases with these characteristics.

Background: The trend of the diffusion of heated tobacco products (HTPs) is a great concern because HTPs have become available worldwide. This study examined the sociodemographic characteristics of HTPs users in Japan, where HTPs were first launched. Methods: This cross-sectional study used data from an online survey conducted in 2017. A total of 4,926 participants, aged 20–69 years, were included. The dependent variable was the type of tobacco products used. The independent variables were age and equivalent income. Two analyses estimated the odds ratios (ORs) for 1) being smokers compared to “non-smokers,” and 2) being “HTP smokers” compared to “only combustible cigarette smokers.” Analyses were stratified by sex. Educational attainment and occupation were also used in the sensitivity analyses. Results: The percentages of “non-smokers,” “only combustible cigarette smokers,” and “HTP smokers” were 82.8%, 14.2%, and 3.0%, respectively. When compared to the oldest participants (aged 60–69), the youngest participants (aged 20–29) tended to be “HTP smokers” (OR 7.90; 95% confidence interval [CI], 3.09–20.22 for men and OR 9.28; 95% CI, 2.14–40.28 for women). Compared to participants with the lowest incomes (

The layered perovskite (MA)2PbI2(SCN)2 (MA = CH3NH3+) is a member of an emerging series of compounds derived from hybrid organic-inorganic perovskites. Here, we successfully synthesized (MA)2PbI2-xBrx(SCN)2 (0 ≤ x < 1.6) by using a solid-state reaction. Despite smaller bromide substitution for iodine, 1% linear expansion along the a axis was observed at x ∼ 0.4 due to a change of the orientation of the SCN- anions. Diffuse reflectance spectra reveal that the optical band gap increases by the bromide substitution, which is supported by the DFT calculations. Curiously, bromine-rich compounds where x ≥ 0.8 are light sensitive, leading to partial decomposition after ∼24 h. This study demonstrates that the layered perovskite (MA)2PbI2(SCN)2 tolerates a wide range of bromide substitution toward tuning the band gap energy.

The success and continued expansion of research on metal-oxo clusters owe largely to their structural richness and wide range of functions. However, while most of them known to date are negatively charged polyoxometalates, there is only a handful of cationic ones, much less functional ones. Here, we show an all-inorganic hydroxyiodide [H₁₀.₇Sb₃₂.₁O₄₄][H₂.₁Sb₂.₁I₈O₆][Sb₀.₇₆I₆]₂·25H₂O (HSbOI), forming a face-centered cubic structure with cationic Sb₃₂O₄₄ clusters and two types of anionic clusters in its interstitial spaces. Although it is submicrometer in size, electron diffraction tomography of HSbOI allowed the construction of the initial structural model, followed by powder Rietveld refinement to reach the final structure. The cationic cluster is characterized by the presence of acidic protons on its surface due to substantial Sb3+ deficiencies, which enables HSbOI to serve as an excellent solid acid catalyst. These results open up a frontier for the exploration and functionalization of cationic metal-oxo clusters containing heavy main group elements., 正電荷の酸化物クラスターの発見 酸触媒としての高い可能性. 京都大学プレスリリース. 2022-06-18., Scientists serendipitously discover rare cluster compound. 京都大学プレスリリース. 2022-06-18.

This study examined the effects of a "community-based center" intervention to prevent the onset of functional disability among residents in disaster-affected areas.We used data from a prospective cohort study conducted from 2010 to 2016 in Iwanuma City, Japan. Participants were community-dwelling independent adults aged ≥65 years. The exposure variable was the experience of using a community-based center. The outcome variable was functional disability onset. The average treatment effect on the treated (ATET) was estimated by adjusting for possible confounders. Additional analysis stratified by sex was conducted considering the sex differences in social participation rates.Among 3794 participants (mean ± SD age = 72.9 ±5.3 years, 46.0% men), 196 (5.2%) used the community-based center, and 849 (22.4%) exhibited disability onset. Of those with functional disabilities, 40 (20.4%) used the community-based center, while 809 (22.5%) did not. The ATET for functional disability onset with community-based center activities across all participants were not significant (ATET: 0.51 years [95% confidence interval [CI] = -0.23; 1.27]). However, the direction of the effect of community-based center activities differed by sex (ATET: -0.14, 95% CI = -2.59; 2.31 for men [n = 18], and 0.66, 95% CI = 0.18; 1.16 for women [n = 178]). Women exhibited a 15.63% (95% CI = 3.58; 27.68) increase in the time until functional disability onset.The use of community-based centers was associated with a longer period without functional disability in women. Geriatr Gerontol Int 2022; 22: 465-470.

Background: Proteinuria is a common adverse event in systemic therapy for hepatocellular carcinoma (HCC). However, whether the presence of pretreatment proteinuria affects the clinical course is still unclear. Method: From 2011 to 2022, 321 patients with unresectable HCC who were treated with systemic therapy as first-line treatment were enrolled in this study. We retrospectively analyzed the presence of pretreatment proteinuria and the treatment course of systemic therapy. Results: In the cohort, 190 patients were tested for proteinuria qualitatively within 3 months before systemic therapy; 75 were treated with sorafenib, 72 were treated with lenvatinib, and 43 were treated with atezolizumab plus bevacizumab. Overall survival tended to be longer for patients treated with lenvatinib and significantly longer with atezolizumab plus bevacizumab in patients without pretreatment proteinuria but not for those treated with sorafenib. Further analysis was performed in 111 patients treated with lenvatinib or atezolizumab plus bevacizumab who had proteinuria measured quantitatively. Multivariate analysis including proteinuria, liver function, and HCC stage revealed that the severity of proteinuria was an independent predictor of prognosis. Conclusion: Pretreatment proteinuria predicts a poorer prognosis in patients with unresectable HCC treated with lenvatinib or atezolizumab plus bevacizumab but not in those treated with sorafenib.

The processing of promising magnetocaloric materials into spheres is one of the important issues on developing high-performance magnetic refrigeration systems. In the present study, we achieved in producing spherical particles of a giant magnetocaloric compound HoB2 by a crucible-free gas atomization process, despite its high melting point of 2350 C. The particle size distribution ranges from 100 to 710 micrometers centered at 212-355 micrometers with the highest yield of 14-20wt% of total melted electrode, which is suitable for magnetic refrigeration systems. The majority of the resulting particles are mostly spherical with no contamination during the processing, while unique microstructures are observed on the surface and inside. These spherical particles exhibit sharp magnetic transitions and huge magnetic entropy change of 0.34 J cm^{-3} K^{-1} for a magnetic field change of 5 T at 15.5 K. The high sphericality and the high magnetocaloric performance suggest that the HoB2 gas-atomized particles have good potential as magnetic refrigerants for use in magnetic refrigerators for hydrogen liquefaction., Comment: 6pages(double column), 6 figures

Metal oxide clusters composed of group 5 metal ions, such as Nb and Ta, exhibit catalytic activities for CO2 fixation to styrene oxide (SO) due to the highly negative natural bonding charge of the terminal O atoms that could work as CO2 activation sites. In this study, tetrabutylammonium (TBA) salts of [TaxNb6−xO19]8− (TBA-TaxNb6−x, x = 0–6) were prepared and Ta-substitution effect on the catalytic properties of TBA-TaxNb6−x for CO2 fixation to SO was investigated. We found that TBA-Ta1Nb5 shows the highest styrene carbonate (SC) selectivity (95%) among TBA-TaxNb6−x, although the SO conversion monotonously increases with the incremental Ta substitution amount. The CO2 fixation to SO under various conditions and in situ X-ray absorption fine structure measurements reveal that CO2 is activated on both terminal O sites coordinated to the Ta (terminal OTa) and Nb (terminal ONb) sites, whereas the activation of SO proceeds on the terminal OTa and/or bridge O sites that are connected to Ta. Density functional theory (DFT) calculations reveal that the terminal OTa of TBA-Ta1Nb5 preferentially adsorbs CO2 compared with other ONb base sites. We conclude that the selective CO2 activation at terminal OTa of TBA-Ta1Nb5 without SO activation is a crucial factor for high SC selectivity in the CO2 fixation to SO.

Recently, a massive magnetocaloric effect near the liquefaction temperature of hydrogen has been reported in the ferromagnetic material HoB$_{2}$. Here we investigate the effects of Dy substitution in the magnetocaloric properties of Ho$_{1-x}$Dy$_{x}$B$_{2}$ alloys ($\textit{x}$ = 0, 0.3, 0.5, 0.7, 1.0). We find that the Curie temperature ($\textit{T}$$_{C}$) gradually increases upon Dy substitution, while the magnitude of the magnetic entropy change |$\Delta \textit{S}_{M}$| at $\textit{T}$ = $\textit{T}_{C}$ decreases from 0.35 to 0.15 J cm$^{-3}$ K$^{-1}$ for a field change of 5 T. Due to the presence of two magnetic transitions in these alloys, despite the change in the peak magnitude of |$\Delta \textit{S}_{M}$|, the refrigerant capacity ($\textit{RC}$) and refrigerant cooling power ($\textit{RCP}$) remains almost constant in all doping range, which as large as 5.5 J cm$^{-3}$ and 7.0 J cm$^{-3}$ for a field change of 5 T. These results imply that this series of alloys could be an exciting candidate for magnetic refrigeration in the temperature range between 10-50 K., Comment: 19 pages, 5 figures, 2 tables

Background Although the majority of survivors of the huge Great East Japan Earthquake and Tsunami evacuated to two types of temporary housings, prefabricated housing and rented housing, health effects of these different environments were unclear. We examined whether prevalent social participation in prefabricated housing brought larger health benefits than in rented housing using the largest health survey data of the disaster survivors. Methods This cross-sectional study used a 2012 survey by the Miyagi Prefectural Government, in which almost all of evacuees were targeted (response rate: 61.6%). Self-rated health (SRH) and psychological distress measured via K6 score were the dependent variables, and social participation was the independent variable. Odds ratios of the social participation on health variables were estimated using logistic regression models. To assess the contribution of social participation, the population attributable fraction (PAF) was estimated. Results The participants lived in prefabricated and rented housing numbered 19,726 and 28,270, respectively. Participants in prefabricated housing had poorer SRH and K6 than those in rented housing. The proportions of participants engaging in social participation of prefabricated and rented housing were 38.2% and 15.4%, respectively. The absence of social participation was significantly associated with poor SRH and K6 among participants in both housing types. The PAFs of social participation with good SRH were 39.5% in prefabricated housing and 14.4% in rented housing. For K6, the PAFs were 47.1% and 19.5% in prefabricated and rented housing, respectively. Conclusion Compared to the residents in rented housing, residents in prefabricated housing had more frequent opportunities for social participation, which was associated with larger health benefits.

The discovery of new extended structures has often led to the development of new fields in chemistry and physics. However, the numerous combinations of metals (or cations) to yield new materials ha...

The solid base catalysis of sodium salts of Lindqvist-type metal oxide clusters was investigated using a Knoevenagel condensation reaction. We successfully synthesized the sodium salts of Ta and Nb mixed-oxide clusters Na8−nHn[(Ta6−xNbx)O19]·15H2O (Na-Ta6−xNbx, n = 0, 1, x = 0–6) and found them to exhibit activity for proton abstraction from nitrile substrates with a pKa value of 23.8, which is comparable to that of the conventional solid base MgO. The Ta-rich Na-Ta6 and Na-Ta4Nb2 exhibited high activity among Ta and Nb mixed-oxide clusters. Synchrotron X-ray diffraction (SXRD) measurements, Fourier-transform infrared (FT-IR) spectroscopy, and X-ray absorption spectroscopy (XAS) revealed the structure of Na-Ta6−xNbx: (1) The crystal structure changed from Na7H[M6O19]·15H2O to Na8[M6O19]·15H2O (M = Ta or Nb) by the anisotropic expansion of the unit cell with an increase in Ta content, (2) Highly symmetrical Lindqvist [Ta6−xNbxO19]8− was generated in Na-Ta4Nb2 and Na-Ta6 because of the symmetrical association of Na+ ions with [Ta6−xNbxO19]8− in the structure. DFT calculation revealed that the Lindqvist structures with high symmetry have large NBO charges on surface oxygen species, which are strongly related to base catalytic activity, whereas the composition hardly affects the NBO charges. The above results showed that the Brønsted base catalysis was sensitive to the symmetry of the Lindqvist [Ta6−xNbxO19]8− structure. These findings contribute to the design of solid base catalysts composed of anionic metal oxide clusters with alkaline-metal cations.

Prevalence of tooth loss has increased due to population aging. Tooth loss negatively affects the overall physical and social well-being of older adults. Understanding the role of socio-demographic and other predictors associated with tooth loss that are measured in non-clinical settings can be useful in community-level prevention. We used high-dimensional epidemiological data to investigate important factors in predicting tooth loss among older adults over a 6-year period of follow-up. Data was from participants of 2010 and 2016 waves of the Japan Gerontological Evaluation Study (JAGES). A total of 19,407 community-dwelling functionally independent older adults aged 65 and older were included in the analysis. Tooth loss was measured as moving from a higher number of teeth category at the baseline to a lower number of teeth category at the follow-up. Out of 119 potential predictors, age, sex, number of teeth, denture use, chewing difficulty, household income, employment, education, smoking, fruit and vegetable consumption, community participation, time since last health check-up, having a hobby, and feeling worthless were selected using Boruta algorithm. Within the 6-year follow-up, 3013 individuals (15.5%) reported incidence of tooth loss. People who experienced tooth loss were older (72.9 ± 5.2 vs 71.8 ± 4.7), and predominantly men (18.3% vs 13.1%). Extreme gradient boosting (XGBoost) machine learning prediction model had a mean accuracy of 90.5% (±0.9%). A visual analysis of machine learning predictions revealed that the prediction of tooth loss was mainly driven by demographic (older age), baseline oral health (having 10–19 teeth, wearing dentures), and socioeconomic (lower household income, manual occupations) variables. Predictors related to wide a range of determinants contribute towards tooth loss among older adults. In addition to oral health related and demographic factors, socioeconomic factors were important in predicting future tooth loss. Understanding the behaviour of these predictors can thus be useful in developing prevention strategies for tooth loss among older adults.

BackgroundThe clinical course of liver injury induced by immune checkpoint inhibitors (ICIs) varies among individuals, and there were few reports on the therapeutic effects of corticosteroids based on the patterns of liver injury.MethodsWe evaluated the characteristics and clinical course of immune-related liver injury in 1087 patients treated with ICIs for advanced malignancies between August 2014 and December 2020. ResultsDuring the follow-up period (median, 270 days), 56 patients (5.2%) had immune-related liver injury (≥Grade 3). The liver-injury patterns were hepatocellular (n = 25, 44.6%), mixed (n = 10, 17.9%), or cholestatic (n = 21, 37.5%), and the median time to onset of liver injury was 36, 85, and 53 days, respectively; the hepatocellular pattern occurred earlier than the other types (P = 0.036). Corticosteroids were administered to 29 (51.8%) patients. While liver injury was improved in almost all patients with the hepatocellular pattern (n = 13/14, 92.9%), that failed to show improvement in over half of the patients with the non-hepatocellular patterns (mixed, n = 8; cholestatic, n = 7), and three patients with mixed patterns needed secondary immunosuppression with mycophenolate mofetil. Liver biopsies performed in 13 patients mainly showed lobular injury, endothelialitis, and spotty necrosis with infiltration of T cells positive for CD3 and CD8, but not CD4 or CD20. Conclusion The incidence pattern and therapeutic response to corticosteroids in immune-related liver injury differs according to the injury type. Although corticosteroids were effective for the hepatocellular pattern, an additional strategy for refractory non-hepatocellular patterns is needed.

Background Hepatocellular carcinoma (HCC) is considered a leading cause of death in patients with haemophilia. Recent advances in the treatment of unresectable HCC with molecular-targeted agents (MTAs) have led to better clinical outcomes. However, the tolerability of MTAs by haemophilic patients with HCC remains unclear. Aim This study aimed to compare the tolerability of MTAs in such patients. Patients and methods From January 2011 to October 2020, five haemophilic patients with HCC were treated with MTAs. Adverse events were assessed in comparison with 265 non-haemophilic patients with HCC. Results The prevalence of hand-foot skin reaction was not higher in the haemophiliacs than in the non-haemophiliacs, whereas the rate of haemorrhagic events was higher in the haemophiliacs (6.0% versus 40.0%, p=0.037). Conclusion Haemophiliacs tolerate long-term MTA use, without the occurrence of life-threatening complications. However, careful observation and prevention are needed for MTA-related gastrointestinal bleeding in haemophiliacs.

Mixed oxide hydride anion systems constitute a novel class of materials exhibiting intriguing properties such as solid-state hydride ion conduction and fast anion exchange. In this contribution we derive the kinetics of hydride ion transport in a mixed oxide–hydride system, SrTiO3–xHx, through isotope exchange and depth profiling. Density functional theory (DFT) calculations indicate that migration of H– to neighboring vacant oxygen lattice sites is fast, but that long-range transport is impeded by slow reorganization of the oxygen sublattice. From measured hydride tracer-diffusion coefficients and the correlation factors derived from DFT, we are able to derive the hydrogen self-diffusion coefficients in SrTiO3–xHx. More generally, the explicit description of hydride ion transport in SrTiO3–xHx through combination of experimental and computational methods reported in this work can be applied to explore anion diffusion in other mixed anion systems.

Magnetic refrigeration exploits the magnetocaloric effect which is the entropy change upon application and removal of magnetic fields in materials, providing an alternate path for refrigeration other than the conventional gas cycles. While intensive research has uncovered a vast number of magnetic materials which exhibits large magnetocaloric effect, these properties for a large number of compounds still remain unknown. To explore new functional materials in this unknown space, machine learning is used as a guide for selecting materials which could exhibit large magnetocaloric effect. By this approach, HoB$_{2}$ is singled out, synthesized and its magnetocaloric properties are evaluated, leading to the experimental discovery of gigantic magnetic entropy change 40.1 J kg$^{-1}$ K$^{-1}$ (0.35 J cm$^{-3}$ K$^{-1}$) for a field change of 5 T in the vicinity of a ferromagnetic second-order phase transition with a Curie temperature of 15 K. This is the highest value reported so far, to our knowledge, near the hydrogen liquefaction temperature thus it is a highly suitable material for hydrogen liquefaction and low temperature magnetic cooling applications., 12 pages including 3 figures and 1 table + 11 pages of supplementary information. Published version available at: https://rdcu.be/b36ep

In this study, the cracking behavior and microstructural, mechanical and thermal characteristics of tungsten–rhenium (W–Re) binary alloys fabricated by laser powder bed fusion (L-PBF) were investigated. Four bulk specimens were prepared by L-PBF: pure W, W–1%Re, W–3%Re and W–10%Re (percentages indicate the mass percent of Re). High-density bulk specimens (relative density > 98.0%) were obtained for pure W and W–Re alloys under the same laser irradiation conditions. The columnar grains elongated along the building direction were gradually refined as the Re content increased. The most remarkable grain refinement was observed for the W–10%Re alloy. Hardness under a high-temperature environment increased with increasing Re content; the micro-Vickers hardnesses of pure W and W–10%Re at 400 °C were 179 ± 4 HV0.1/30 and 281 ± 5 HV0.1/30, respectively. Observations with a scanning electron microscope revealed that the 10 mass% Re addition resulted in a shorter and narrower crack morphology in comparison with pure W and consequently reduced crack area by 59%. Furthermore, the anisotropy of the thermal diffusivity was mitigated in the high Re content specimens, suggesting that, at high Re content, thermal diffusivity is affected less by cracks than by the effect of Re atoms on heat carrier transfer via isotropic scattering.

Consumption of green tea without sugar, as well as social networks, are associated with a lower risk of tooth loss. There is a possibility of confounding both factors because tea is often drunk with friends. Therefore, the present study aimed to examine whether green tea consumption is beneficially associated with the number of remaining teeth, while considering social networks. This cross-sectional study was based on the Japan Gerontological Evaluation Study (JAGES) in 2016. Self-administered questionnaires containing questions about green tea consumption were mailed to 34,567 community-dwelling residents aged &ge, 65 years. We used the number of remaining teeth as a dependent variable, and green tea consumption and the number of friends met over the past month (social network size) as independent variables. Linear regression models with multiple imputation were used. A total of 24,147 people responded (response rate = 69.9%), and 22,278 valid data were included into our analysis. Participants&rsquo, mean age was 74.2 years (standard deviation = 6.3), and 45.9% were men. Among the participants, 52.2% had &ge, 20 teeth, 34.2% drank 2&ndash, 3 cups of green tea per day, and 32.6% met &ge, 10 people over the past month. After adjusting for all potential confounders, both higher green tea consumption and a larger social network size were associated with more remaining teeth (both p for trend &lt, 0.001). The association of green tea was greater among those with smaller social networks (p for interaction &lt, 0.05). The protective association of green tea was remarkable among people with smaller social networks.

We have developed an approach to control the carrier density in various material under high pressure by the combination of an electric double layer transistor (EDLT) with a diamond anvil cell (DAC). In this study, this EDLT-DAC was applied to a Bi thin film, and here we report the field-effect under high pressure in the material. Our EDLT-DAC is a promising device for exploring unknown physical phenomena such as high transition-temperature superconductivity (HTS)., 10 pages, 4 figures

We report the fabrication of ErAl2 magnetocaloric wires by a powder-in-tube method (PIT) and the evaluation of magnetic entropy change through magnetization measurements. The magnetic entropy change of ErAl2 PIT wires exhibits similar behavior to the bulk counterpart, while its magnitude is reduced by the decrease in the volume fraction of ErAl2 due to the surrounding non-magnetic sheaths. We find that another effect reduces the magnetic entropy change of the ErAl2 PIT wires around the Curie temperature, and discuss its possible origin in terms of a correlation between magnetic properties of ErAl2 and mechanical properties of sheath material., Comment: This is the version of the article before peer review or editing, as submitted by an author to {insert name of Journal}. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at {https://dx.doi.org/10.1088/1361-6463/ab5c71}

Magnetic properties of $\mathrm{MnS}{\mathrm{b}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ were examined through magnetic susceptibility, specific-heat, and neutron-diffraction measurements. As opposed to isostructural $\mathrm{MnB}{\mathrm{i}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ with the antiferromagnetic ground state, $\mathrm{MnS}{\mathrm{b}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ develops a spontaneous magnetization below 25 K. From our first-principles calculations on the material in a ferromagnetic state, the state could be interpreted as a type-II Weyl semimetal state with broken time-reversal symmetry. Detailed structural refinements using x-ray-diffraction and neutron-diffraction data reveal the presence of site mixing between Mn and Sb sites, leading to the ferrimagnetic ground state. With theoretical calculations, we found that the presence of site mixing plays an important role for the interlayer Mn-Mn ferromagnetic interactions.

To optimize the giant magnetocaloric properties of HoB2, we synthesized and characterized the magnetocaloric properties of Ho1-xGdxB2 (0.1 ≤ x ≤ 0.4) alloys. We found out that Gd enters stoichiometrically and randomly into the Ho site, leading to a Vegard-type structural change. The addition of spherical S7/2 Gd3+ moments prompts an enhancement in Curie temperature from 15 K to 30 K (at x = 0.4), a reduction in peak value of the magnetic entropy change, from 0.35 (40.1) to 0.17 (20.2) J cm−3 K−1 (J kg−1 K−1), and a broadening of the magnetic entropy change curves. The overall influence is a relatively high refrigerant capacity and relative cooling power, peaking at 6.07 (711) and 7.68 (899) J cm−3 (J kg−1) for x = 0.2, and an extension of the thermal working range to higher temperatures. Unlike Ho1−xDyxB2 alloys, the Gd substituted samples show no magnetic hysteresis. Furthermore, scaling analysis of the entropy curves suggests a second-order phase transition for the ferromagnetic transition in these alloys. Thus, Ho1-xGdxB2 alloys are potential candidates for cryogenic refrigeration applications.

Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T[2]PTe[2] (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti[2]PTe[2]). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid., 重金属を固体中で選択的に吸収する材料の発見 : 電子機器からの新たな金属回収法などの開発に期待. 京都大学プレスリリース. 2016-12-20.

The NiAs-type structure is one of the most common structures in solids, but metal order has been almost exclusively limited to chalcogenides. The synthesis of HfMnSb2 is reported with a novel metal-ordered NiAs-type structure. HfMnSb2 undergoes a conical spin order below 270 K, in marked contrast to conventional magnetic order observed in NiAs-type pnictides. We argue that the layered arrangement of Hf and Mn makes it a quasi 2D magnet, where the Mn layers with localized magnetic moments (Mn(2+) ; S=5/2) can interact only through RKKY interactions, instead of metal-metal bonding that is otherwise dominant for typical NiAs-type pnictides. This result suggests that controlling order-disorder in NiAs-type pnictides enables a study of 2D-to-3D crossover behavior in itinerant magnetic system.

In this study, the effects of fabrication conditions on the microstructure, pore characteristics and gas retention of pure tungsten specimens prepared by laser powder bed fusion (LPBF) were investigated. The LPBF specimens contained micro- and nano- sized pores as internal defects. By optimizing the laser irradiation conditions, the formation of micropores was suppressed. The densest LPBF specimen was obtained when the input energy density was adjusted to be 411 J/mm3, and the relative density of the specimen measured by utilizing Archimedes' principle reached 98.58 ± 0.25% (19.03 ± 0.05 g/cm3). Heat treatment at a high temperature (1900 °C) was effective to reduce the number density of nanopores. The compositions and amounts of internal gas in the specimens were examined using a quadrupole mass spectrometer. The results indicated that the specimens contained the argon (Ar), which was used as the shielding gas. The Ar retention was correlated with the number density of nanopores in the specimens and not with the density of micropores. The Ar retention decreased to almost half that in the as-fabricated specimen after the heat treatment at 1900 °C. These observations suggest that Ar gas was trapped in nanopores in the LPBF material. It was demonstrated that a part of the trapped Ar dissolved and diffused in grains during the heat treatment and was released to the outside.

Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. Separately, lattice strain between thin film oxides and a substrate induces improved functions and novel states of matter, while little attention has been paid to changes in chemical composition. Here we combine these two aspects to achieve strain-induced creation and switching of anion-vacancy patterns in perovskite films. Epitaxial SrVO3 films are topochemically converted to anion-deficient oxynitrides by ammonia treatment, where the direction or periodicity of defect planes is altered depending on the substrate employed, unlike the known change in crystal orientation. First-principles calculations verified its biaxial strain effect. Like oxide heterostructures, the oxynitride has a superlattice of insulating and metallic blocks. Given the abundance of perovskite families, this study provides new opportunities to design superlattices by chemically modifying simple perovskite oxides with tunable anion-vacancy patterns through epitaxial lattice strain., Using strain to control oxynitride properties. 京都大学プレスリリース. 2020-12-01., 原子空孔の配列を制御する新手法の発見. 京都大学プレスリリース. 2020-12-02.

We report the adiabatic temperature change in ErAl2 magnetocaloric wires fabricated by a powder-in-tube (PIT) process. The adiabatic temperature change of the PIT wires is found to be determined by not only the volume fraction of ErAl2 core but also the magnitude relationship between the specific heat of the ErAl2 core and the metal sheath. We propose a quantitative analysis method for calculating the temperature and core volume fraction dependence of adiabatic temperature change in the PIT wire, whose formula is applicable to also various magnetocaloric composites, useful to estimate the magnetocaloric response prior to fabrication., Comment: 14 pages, 5 figures