Publications by authors named "Hirahara T"

We demonstrate the impact of high-density calcium introduction into Ca-intercalated bilayer graphene on a SiC substrate, wherein a metallic layer of Ca has been identified at the interface. We have discerned that the additional Ca layer engenders a free-electron-like band, which subsequently hybridizes with a Dirac band, leading to the emergence of a van Hove singularity. Coinciding with this, there is an increase in the critical temperature for superconductivity.

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Carbon edge sites have been widely studied because of their importance in surface reactivity and electronic properties. The surface chemistry of the carbon edge sites is relevant to various reactions, and carbon active sites are key topics in many applications. Temperature-programmed desorption (TPD) and temperature-programmed reaction (TPR) techniques are used to clarify the fate of oxygen atoms present as CO-yielding functional groups on the activated carbon during heat treatment in hydrogen with an argon balance atmosphere.

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Although the scope of pharmacists' work has expanded in Japan, people's perception of this is unclear. To contribute to medical care together with non- and health care professionals, clarifying the perceptions of these groups is important to best utilize pharmacist professionals. We conducted a cross-sectional questionnaire survey among non-health care professionals (n = 487) and nurses (n = 151), medical doctors (n = 133), and pharmacists (n = 204) regarding the work of pharmacists.

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Ca-intercalation has enabled superconductivity in graphene on SiC. However, the atomic and electronic structures that are critical for superconductivity are still under discussion. We find an essential role of the interface between monolayer graphene and the SiC substrate for superconductivity.

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A magnetic skyrmion induced on a ferromagnetic topological insulator (TI) is a real-space manifestation of the chiral spin texture in the momentum space and can be a carrier for information processing by manipulating it in tailored structures. Here, a sandwich structure containing two layers of a self-assembled ferromagnetic septuple-layer TI, Mn(BiSb)Te (MnBST), separated by quintuple layers of TI, (BiSb)Te (BST), is fabricated and skyrmions are observed through the topological Hall effect in an intrinsic magnetic topological insulator for the first time. The thickness of BST spacer layer is crucial in controlling the coupling between the gapped topological surface states in the two MnBST layers to stabilize the skyrmion formation.

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In electrochemical devices, it is important to control the ionic transport between the electrodes and solid electrolytes. However, it is difficult to tune the transport without applying an electric field. This paper presents a method to modulate the transport via tuning of the electrochemical potential difference by controlling the electronic states at the interfaces.

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Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the quantum anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure MnBiTe/BiTe where multiple magnetic layers are inserted into the topmost quintuple layer of the original topological insulator BiTe. A massive Dirac cone (DC) with a gap of 40-75 meV at 16 K is observed.

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We investigated the superconducting transport properties of the one-unit-cell FeSe ultrathin films epitaxially grown on undoped SrTiO_{3}(001) (STO) with a well-defined surface structure by in situ independently-driven four-point-probe measurements. Our results unambiguously revealed the detection of the two-dimensional electrical conduction of the films without parallel conduction through the underlying substrate, both in the normal and superconducting states. The monolayer film exhibited a superconducting transition at an onset temperature of 40 K.

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Background: The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are representative blood markers of systemic inflammatory responses. However, the clinical significance of the combination of these markers is unclear. This study aimed to investigate the NLR and PLR in patients with advanced gastric cancer treated with chemotherapy and assess the clinical utility of a new blood score combining the NLR and PLR (NLR-PLR score) as a predictor of tumor response and prognosis.

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We herein report the case of a 62-year-old man diagnosed with Legionella pneumonia while engaged in recovery work in a flooded area after the Heavy Rain Event of July 2018 in Japan. The patient was intubated and maintained on mechanical ventilation and continuous hemodiafiltration. He was also administered antimicrobial therapy with ciprofloxacin and azithromycin.

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Purpose: Few studies have assessed the prevalence of perfusion abnormality with migraine. This study aimed to determine the prevalence and topography of perfusion abnormality on three-dimensional (3D) arterial spin labeling (ASL) and assess the correlation between perfusion abnormality and clinical data in pediatric and adolescent patients with migraine.

Methods: Forty-nine consecutive pediatric and adolescent patients with migraine were enrolled, and they underwent 3 T MRI, including 3D ASL.

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Since the advent of graphene, a variety of studies have been performed to elucidate its fundamental physics, or to explore its practical applications. Gate-tunable resistance is one of the most important properties of graphene and has been studied in 1-3 layer graphene in a number of efforts to control the band gap to obtain a large on-off ratio. On the other hand, the transport property of multilayer graphene with more than three layers is less well understood.

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How atoms acquire three-dimensional bulk character is one of the fundamental questions in materials science. Before addressing this question, how atomic layers become a bulk crystal might give a hint to the answer. While atomically thin films have been studied in a limited range of materials, a recent discovery showing how to mechanically exfoliate bulk crystals has opened up the field to study the atomic layers of various materials.

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Electrically insulating graphite particles were prepared by coating graphite with electrically insulating materials a two-step mechanical mixing process. Graphite particles were treated with a binder in the 1 mixing process and coated with an electrically insulating particle in the 2 mixing process under high shear forces within a short processing time (below 1 min). Micron-sized graphite particles were successfully coated with various inorganic particles of appropriate particle diameter.

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This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene-thiophene copolymer having two different chiral side chains at the 9-position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains.

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A 59-year-old man developed brain embolism in the frontal and parietal cortex. Brain CT showed a high-density spot in the upper branch of the left middle cerebral artery, indicating calcified cerebral embolism. Calcified amorphous tumor attached to the mitral valve was identified as the cause of embolism.

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Inducing magnetism into topological insulators is intriguing for utilizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) for technological applications. While most studies have focused on doping magnetic impurities to open a gap at the surface-state Dirac point, many undesirable effects have been reported to appear in some cases that makes it difficult to determine whether the gap opening is due to the time-reversal symmetry breaking or not. Furthermore, the realization of the QAHE has been limited to low temperatures.

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We performed high-resolution photon-energy and polarization-dependent ARPES measurements on ultrathin Bi(111) films [6-180 bilayers (BL), 2.5-70 nm thick] formed on Si(111). In addition to the extensively studied surface states (SSs), the edge of the bulk valence band was clearly measured by using S-polarized light.

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Introduction: Cryptococcal meningitis is a severe infection among immunosuppressed individuals, with a high mortality rate. Although amphotericin B is the first-choice drug for treatment, its use is restricted when adverse effects are clinically problematic. The usefulness of intraventricular infusion of antifungal drugs through Ommaya reservoirs for cryptococcal meningitis treatment has been unconfirmed.

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We performed in situ magnetotransport measurements on ultrathin Bi(111) films [4-30 bilayers (BLs), 16-120 Å thick] to elucidate the role of bulk or surface states in the transport phenomena. We found that the temperature dependence of the film conductivity shows no thickness dependence for the 6-16 BL films and is affected by the electron-electron scattering, suggesting surface-state dominant contribution. In contrast, the weak antilocalization effect observed by applying a magnetic field shows clear thickness dependence, indicating bulk transport.

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Background: Listeria monocytogenes (L. monocytogenes) is a rare causative pathogen of brain abscess that is often found in immunocompromised patients. Although patients with supratentorial listerial abscesses showed a longer survival with surgical drainage, the standard therapy for patients with subtentorial lesions has not been established.

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A bulk material comprising stacked nanosheets of nickel bis(dithiolene) complexes is investigated. The average oxidation number is -3/4 for each complex unit in the as-prepared sample; oxidation or reduction respectively can change this to 0 or -1. Refined electrical conductivity measurement, involving a single microflake sample being subjected to the van der Pauw method under scanning electron microscopy control, reveals a conductivity of 1.

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