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1.
Phys Rev Lett ; 127(14): 145701, 2021 Oct 01.
Article in English | MEDLINE | ID: mdl-34652188

ABSTRACT

We report complex behaviors in the phase evolution of transition-metal dichalcogenide IrTe_{2} thin flakes, captured with real-space observations using scanning Raman microscopy. The phase transition progresses via growth of a small number of domains, which is unlikely in statistical models that assume a macroscopic number of nucleation events. Consequently, the degree of phase evolution in the thin flakes is quite variable for the selected specimen and for a repeated measurement sequence, representing the emergence of complexity in the phase evolution. In the ∼20-µm^{3}-volume specimen, the complex phase evolution results in the emergent coexistence of a superconducting phase that originally requires chemical doping to become thermodynamically stable. These findings indicate that the complexity involved in phase evolution considerably affects the physical properties of a small-sized specimen.

2.
Nat Commun ; 11(1): 2466, 2020 May 18.
Article in English | MEDLINE | ID: mdl-32424170

ABSTRACT

Topologically nontrivial materials host protected edge states associated with the bulk band inversion through the bulk-edge correspondence. Manipulating such edge states is highly desired for developing new functions and devices practically using their dissipation-less nature and spin-momentum locking. Here we introduce a transition-metal dichalcogenide VTe2, that hosts a charge density wave (CDW) coupled with the band inversion involving V3d and Te5p orbitals. Spin- and angle-resolved photoemission spectroscopy with first-principles calculations reveal the huge anisotropic modification of the bulk electronic structure by the CDW formation, accompanying the selective disappearance of Dirac-type spin-polarized topological surface states that exist in the normal state. Thorough three dimensional investigation of bulk states indicates that the corresponding band inversion at the Brillouin zone boundary dissolves upon the CDW formation, by transforming into anomalous flat bands. Our finding provides a new insight to the topological manipulation of matters by utilizing CDWs' flexible characters to external stimuli.

3.
Phys Rev Lett ; 124(4): 047002, 2020 Jan 31.
Article in English | MEDLINE | ID: mdl-32058775

ABSTRACT

GeTe is a chemically simple IV-VI semiconductor which bears a rich plethora of different physical properties induced by doping and external stimuli. Here, we report a superconductor-semiconductor-superconductor transition controlled by finely-tuned In doping. Our results reveal the existence of a critical doping concentration x_{c}=0.12 in Ge_{1-x}In_{x}Te, where various properties, including structure, resistivity, charge carrier type, and the density of states, take either an extremum or change their character. At the same time, we find indications of a change in the In-valence state from In^{3+} to In^{1+} with increasing x by core-level photoemission spectroscopy, suggesting that this system is a new promising playground to probe valence fluctuations and their possible impact on structural, electronic, and thermodynamic properties of their host.

4.
Phys Rev Lett ; 119(20): 207001, 2017 Nov 17.
Article in English | MEDLINE | ID: mdl-29219367

ABSTRACT

Structural, magnetic, and electrical characterizations reveal that SnP with an unusual valence state (nominally Sn^{3+}) undergoes a ferroelectriclike structural transition from a simple NaCl-type structure to a polar tetragonal structure at approximately 250 K at ambient pressure. First-principles calculations indicate that the experimentally observed tetragonal distortion enhances the charge transfer from Sn to P, thereby making the polar tetragonal phase energetically more stable than the nonpolar cubic phase. Hydrostatic pressure is found to promptly suppress the structural phase transition in SnP, leading to the emergence of bulk superconductivity in a phase-competitive manner. These findings suggest that control of ferroelectriclike instability in a metal can be a promising way for creating novel superconductors.

6.
Dermatology ; 195 Suppl 2: 107-10, 1997.
Article in English | MEDLINE | ID: mdl-9403267

ABSTRACT

To our knowledge, there are no published papers detailing antisepsis for injection sites. In view of this, the efficacies of povidone-iodine (PVP-I) ethanol solution and chlorhexidine (CH) ethanol, the agents most commonly used for antisepsis of the operative field, were compared. Before and after the injection site was disinfected with either of these antiseptics, specimens of indigenous bacteria on the skin were collected by the cylinder scrub method, and the bacteria reduction rate and the reduction factor (RF) were determined to evaluate the efficacy of antisepsis. The bacteria reduction rate and RF value obtained for PVP-I ethanol were 95.1 +/- 11.2 and 2.1 +/- 0.9% and those for CH ethanol were 93.5 +/- 9.3 and 1.8 +/- 0.9%. Since there were individual differences in cell count before antisepsis, no significant difference was seen in bactericidal activity. However, slightly more favorable results were obtained with PVP-I ethanol. Although it is impossible to eradicate completely the indigenous microbes with currently available methods, it is considered important for the prevention of infection of the injection site to decrease bacterial counts as much as possible.


Subject(s)
Anti-Infective Agents, Local/therapeutic use , Bacteria/drug effects , Iodophors/therapeutic use , Povidone-Iodine/therapeutic use , Skin/microbiology , Anti-Infective Agents, Local/administration & dosage , Antisepsis , Bacteria/growth & development , Bacterial Infections/prevention & control , Chemoprevention , Chlorhexidine/administration & dosage , Chlorhexidine/therapeutic use , Colony Count, Microbial , Cross-Over Studies , Ethanol/administration & dosage , Ethanol/therapeutic use , Humans , Injections/adverse effects , Iodophors/administration & dosage , Povidone-Iodine/administration & dosage
8.
Acta Neuropathol ; 88(4): 384-8, 1994.
Article in English | MEDLINE | ID: mdl-7839833

ABSTRACT

A 57-year-old woman with primary intracerebral osteosarcoma is reported. The tumor was identified by computed tomography as a mass with hemorrhage in the right parietal lobe. The surgical and pathological examinations confirmed an osteosarcoma of intracerebral origin. She suffered from repeated local recurrence of the tumor and died about 1 year after the onset. The pathological findings showed features of osteoblastic osteosarcoma with numerous osteoclast-like multinucleated giant cells. Immunohistochemically, tumor cells were positive for vimentin, and partially for actin. Multinucleated giant cells were reactive with vimentin and CD68 antibodies. Ultrastructurally, tumor cells were rich with rough endoplasmic reticulum. These findings are consistent with the histological features of skeletal or extraskeletal osteosarcoma. This is the third case of primary intracerebral osteosarcoma reported in the literature and the first one analyzed ultrastructurally.


Subject(s)
Brain Neoplasms/pathology , Osteosarcoma/pathology , Brain Neoplasms/chemistry , Brain Neoplasms/ultrastructure , Female , Humans , Immunoenzyme Techniques , Middle Aged , Osteosarcoma/chemistry , Osteosarcoma/ultrastructure
9.
Neurol Med Chir (Tokyo) ; 32(4): 232-5, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1378570

ABSTRACT

Left transverse sinus thrombosis developed in a 27-year-old male with ulcerative colitis. The diagnosis was based on cerebral angiography and magnetic resonance (MR) imaging, the latter of which clearly delineated the intraluminal thrombus. Serial MR images demonstrated thrombus organization. The use of this method in the diagnosis of cerebral sinus thrombosis might reduce the need for cerebral angiography.


Subject(s)
Colitis, Ulcerative/complications , Sinus Thrombosis, Intracranial/etiology , Adult , Cerebral Angiography , Colitis, Ulcerative/blood , Humans , Incidence , Magnetic Resonance Imaging , Male , Sinus Thrombosis, Intracranial/diagnostic imaging , Sinus Thrombosis, Intracranial/pathology , Thromboembolism/epidemiology , Thromboembolism/etiology
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