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Miyoshi T, Maeno Y, Matsuda T, Ito Y, Inamura N, Kim KS, Shiraishi I, Kurosaki K, Ikeda T, Sago H. Neurodevelopmental outcome after antenatal therapy for fetal supraventricular tachyarrhythmia: 3-year follow-up of multicenter trial. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2023; 61:49-58. [PMID: 36350016 DOI: 10.1002/uog.26113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/30/2022] [Accepted: 10/20/2022] [Indexed: 05/27/2023]
Abstract
OBJECTIVES Although many studies have supported the efficacy of transplacental treatment for fetal supraventricular tachyarrhythmia, the long-term neurodevelopmental outcome after antenatal antiarrhythmic treatment is not well understood. The aim of this study was to investigate the prognosis and neurodevelopmental outcome at 36 months of corrected age and the incidence of tachyarrhythmia after birth, following protocol-defined antenatal therapy for fetal supraventricular tachyarrhythmia. METHODS This was a 3-year follow-up study of a multicenter trial that evaluated the efficacy and safety of protocol-defined transplacental treatment for fetal supraventricular tachycardia (SVT) and atrial flutter (AFL). The primary endpoints were mortality and neurodevelopmental impairment (NDI) at 36 months of corrected age. NDI was defined as any of the following outcomes: cerebral palsy, bilateral blindness, bilateral deafness or neurodevelopmental delay. Neurodevelopmental delay was evaluated using appropriate developmental quotient scales, mainly the Kyoto Scale of Psychological Development, or examination by pediatric neurologists. The detection rate of tachyarrhythmia at birth and at 18 and 36 months of corrected age was also evaluated as the secondary endpoint. In addition, the association of NDI at 36 months with perinatal and postnatal factors was analyzed. RESULTS Of 50 patients enrolled in the original trial, one withdrew consent and in two there was fetal death, leaving 47 patients available for enrollment in this follow-up study. Of these, 45 cases were available for analysis after two infants were lost to follow-up. The mortality rate was 2.2% (1/45) during a median follow-up of 3.2 (range, 2.1-9.4) years. The infant died at the age of 2.1 years. Another infant had missing neurodevelopmental assessment data. In the remaining 43 infants, at 36 months of corrected age, NDI was detected in 9.3% (4/43) overall and in two of three (66.7%) cases with fetal hydrops with subcutaneous edema. Cerebral palsy was noted in two infants with severe subcutaneous edema or ascites at an early gestational age. Neurodevelopmental delay was found in two infants with severe congenital abnormalities (one with tuberous sclerosis and the other with heterotaxy syndrome). Tachyarrhythmia was present in 31.9% (15/47) cases in the neonatal period and decreased to 8.9% (4/45) and 4.5% (2/44) at 18 and 36 months of corrected age, respectively. The median ventricular rate at diagnosis was significantly higher in infants with NDI compared to those without (265 vs 229 bpm; P = 0.003). In infants with NDI, compared to those without, fetal hydrops with subcutaneous edema at diagnosis was more common (50.0% vs 2.6%; P = 0.019) and the duration of fetal effusion was longer (median, 10.5 vs 0 days; P = 0.013). Postnatal arrhythmia and physical development abnormalities were not associated with NDI. CONCLUSIONS This multicenter 3-year follow-up study is the first to demonstrate the long-term mortality and morbidity of infants born following protocol-defined transplacental treatment for fetal SVT and AFL. NDI was associated with the presence of fetal hydrops with subcutaneous edema at diagnosis and longer duration of fetal effusion. Neurodevelopmental delay was detected only in infants with severe congenital abnormalities. Therefore, in infants that have undergone antenatal treatment for fetal tachyarrhythmia and in which there are no comorbidities, the risk of NDI is low. However, in those with fetal hydrops with subcutaneous edema and/or associated severe congenital abnormalities, the risk for long-term neurologic morbidity might be considered somewhat increased. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.
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Kinjo K, Manago M, Kitagawa S, Mao ZQ, Yonezawa S, Maeno Y, Ishida K. Superconducting spin smecticity evidencing the Fulde-Ferrell-Larkin-Ovchinnikov state in Sr 2RuO 4. Science 2022; 376:397-400. [PMID: 35446631 DOI: 10.1126/science.abb0332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Translational symmetry breaking is antagonistic to static fluidity but can be realized in superconductors, which host a quantum-mechanical coherent fluid formed by electron pairs. A peculiar example of such a state is the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, induced by a time-reversal symmetry-breaking magnetic field applied to spin-singlet superconductors. This state is intrinsically accompanied by the superconducting spin smecticity, spin density-modulated fluidity with spontaneous translational-symmetry breaking. Detection of such spin smecticity provides unambiguous evidence for the FFLO state, but its observation has been challenging. Here, we report the characteristic "double-horn" nuclear magnetic resonance spectrum in the layered superconductor Sr2RuO4 near its upper critical field, indicating the spatial sinusoidal modulation of spin density that is consistent with superconducting spin smecticity. Our work reveals that Sr2RuO4 provides a versatile platform for studying FFLO physics.
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Uchida K, Mattoni G, Yonezawa S, Nakamura F, Maeno Y, Tanaka K. High-Order Harmonic Generation and Its Unconventional Scaling Law in the Mott-Insulating Ca_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2022; 128:127401. [PMID: 35394320 DOI: 10.1103/physrevlett.128.127401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/17/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Competition and cooperation among orders is at the heart of many-body physics in strongly correlated materials and leads to their rich physical properties. It is crucial to investigate what impact many-body physics has on extreme nonlinear optical phenomena, with the possibility of controlling material properties by light. However, the effect of competing orders and electron-electron correlations on highly nonlinear optical phenomena has not yet been experimentally clarified. Here, we investigated high-order harmonic generation from the Mott-insulating phase of Ca_{2}RuO_{4}. Changing the gap energy in Ca_{2}RuO_{4} as a function of temperature, we observed a strong enhancement of high order harmonic generation at 50 K, increasing up to several hundred times compared to room temperature. We discovered that this enhancement can be well reproduced by an empirical scaling law that depends only on the material gap energy and photon emission energy. Such a scaling law can hardly be explained by the electronic structure change in the single particle model and has not been predicted by previous theoretical studies on HHG in the simple Mott-Hubbard model. Our results suggest that the highly nonlinear optical response of strongly correlated materials is influenced by competition among the multiple degrees of freedom and electron-electron correlations.
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Fittipaldi R, Hartmann R, Mercaldo MT, Komori S, Bjørlig A, Kyung W, Yasui Y, Miyoshi T, Olde Olthof LAB, Palomares Garcia CM, Granata V, Keren I, Higemoto W, Suter A, Prokscha T, Romano A, Noce C, Kim C, Maeno Y, Scheer E, Kalisky B, Robinson JWA, Cuoco M, Salman Z, Vecchione A, Di Bernardo A. Unveiling unconventional magnetism at the surface of Sr 2RuO 4. Nat Commun 2021; 12:5792. [PMID: 34608149 PMCID: PMC8490454 DOI: 10.1038/s41467-021-26020-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/14/2021] [Indexed: 11/09/2022] Open
Abstract
Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr2RuO4, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr2RuO4 is still ongoing, a deeper understanding of the Sr2RuO4 normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr2RuO4 in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr2RuO4 surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.
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Petsch AN, Zhu M, Enderle M, Mao ZQ, Maeno Y, Mazin II, Hayden SM. Reduction of the Spin Susceptibility in the Superconducting State of Sr_{2}RuO_{4} Observed by Polarized Neutron Scattering. PHYSICAL REVIEW LETTERS 2020; 125:217004. [PMID: 33275021 DOI: 10.1103/physrevlett.125.217004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 07/01/2020] [Accepted: 10/14/2020] [Indexed: 06/12/2023]
Abstract
Recent observations [A. Pustogow et al., Nature (London) 574, 72 (2019).NATUAS0028-083610.1038/s41586-019-1596-2] of a drop of the ^{17}O nuclear magnetic resonance (NMR) Knight shift in the superconducting state of Sr_{2}RuO_{4} challenged the popular picture of a chiral odd-parity paired state in this compound. Here we use polarized neutron scattering (PNS) to show that there is a 34±6% drop in the magnetic susceptibility at the Ru site below the superconducting transition temperature. We measure at lower fields H∼1/3H_{c2} than a previous PNS study allowing the suppression to be observed. The PNS measurements show a smaller susceptibility suppression than NMR measurements performed at similar field and temperature. Our results rule out the chiral odd-parity d=z[over ^](k_{x}±ik_{y}) state and are consistent with several recent proposals for the order parameter including even-parity B_{1g} and odd-parity helical states.
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Steffens P, Sidis Y, Kulda J, Mao ZQ, Maeno Y, Mazin II, Braden M. Spin Fluctuations in Sr_{2}RuO_{4} from Polarized Neutron Scattering: Implications for Superconductivity. PHYSICAL REVIEW LETTERS 2019; 122:047004. [PMID: 30768293 DOI: 10.1103/physrevlett.122.047004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Indexed: 06/09/2023]
Abstract
Triplet pairing in Sr_{2}RuO_{4} was initially suggested based on the hypothesis of strong ferromagnetic spin fluctuations. Using polarized inelastic neutron scattering, we accurately determine the full spectrum of spin fluctuations in Sr_{2}RuO_{4}. Besides the well-studied incommensurate magnetic fluctuations, we do find a sizable quasiferromagnetic signal, quantitatively consistent with all macroscopic and microscopic probes. We use this result to address the possibility of magnetically driven triplet superconductivity in Sr_{2}RuO_{4}. We conclude that, even though the quasiferromagnetic signal is stronger and sharper than previously anticipated, spin fluctuations alone are not enough to generate a triplet state strengthening the need for additional interactions or an alternative pairing scenario.
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Watanabe S, Yamaguchi OU, Masumoto AI, Maeno Y, Kawashima Y, Ishimoto O, Sugawara S, Yoshizawa H, Kikuchi T, Nukiwa T, Kobayashi K. Phase I Study Evaluating the Combination of Afatinib with Carboplatin and Pemetrexed After First-line EGFR-TKIs. Anticancer Res 2018; 38:4699-4704. [PMID: 30061238 DOI: 10.21873/anticanres.12776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 06/27/2018] [Accepted: 06/29/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Promising reports have described the combination of first-generation epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR-TKIs) with carboplatin plus pemetrexed or bevacizumab. However, no analysis of afatinib with platinum-doublet chemotherapies has been performed. PATIENTS AND METHODS We evaluated the safety and antitumor efficacy of afatinib combined with carboplatin and pemetrexed in EGFR-mutated non-small-cell lung cancer (NSCLC) patients who progressed during first-generation EGFR-TKIs. RESULTS Ten patients received 20 or 30 mg/day afatinib with carboplatin (area under the curve, 5) and pemetrexed (500 mg/m2). Dose-limiting toxicities included delay of afatinib ≥14 days, grade 3 diarrhea, grade 3 hypokalemia, grade 3 serum amylase increase and grade 4 thrombocytopenia. The recommended dose of afatinib was 20 mg/day in this combination therapy. Overall response rate was 30% and median progression-free survival was 13.7 months. CONCLUSION This is the first study to investigate the combination of afatinib, carboplatin and pemetrexed. At the recommended dose, this combination was well tolerated and had a good clinical efficacy.
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Nomura T, Maeno Y, Abramowitz Y, Yoon S, Kubo S, Jilaihawi H, Kawamori H, Kazuno Y, Miyasaka M, Takahashi N, Kashif M, Chakravarty T, Nakamura M, Sharma R, Makkar R. P6311Prognostic impact of permanent pacemaker implantation in patients with low left ventricular ejection fraction following transcatheter aortic valve replacement. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p6311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Yamaguchi O, Watanabe S, Masumoto A, Maeno Y, Kawashima Y, Ishimoto O, Sugawara S, Yoshizawa H, Kobayashi K, Nukiwa T. P2.03-021 A Phase I Study Evaluating the Combination of Afatinib, Carboplatin and Pemetrexed after Failure of 1st Generation EGFR-TKIs. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.09.1272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kunkemöller S, Steffens P, Link P, Sidis Y, Mao ZQ, Maeno Y, Braden M. Absence of a Large Superconductivity-Induced Gap in Magnetic Fluctuations of Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2017; 118:147002. [PMID: 28430489 DOI: 10.1103/physrevlett.118.147002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Indexed: 06/07/2023]
Abstract
Inelastic neutron scattering experiments on Sr_{2}RuO_{4} determine the spectral weight of the nesting induced magnetic fluctuations across the superconducting transition. There is no observable change at the superconducting transition down to an energy of ∼0.35 meV, which is well below the 2Δ values reported in several tunneling experiments. At this and higher energies magnetic fluctuations clearly persist in the superconducting state. Only at energies below ∼0.3 meV can evidence for partial suppression of spectral weight in the superconducting state be observed. This strongly suggests that the one-dimensional bands with the associated nesting fluctuations do not form the active, highly gapped bands in the superconducting pairing in Sr_{2}RuO_{4}.
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Kondo T, Ochi M, Nakayama M, Taniguchi H, Akebi S, Kuroda K, Arita M, Sakai S, Namatame H, Taniguchi M, Maeno Y, Arita R, Shin S. Orbital-Dependent Band Narrowing Revealed in an Extremely Correlated Hund's Metal Emerging on the Topmost Layer of Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2016; 117:247001. [PMID: 28009182 DOI: 10.1103/physrevlett.117.247001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Indexed: 06/06/2023]
Abstract
We use a surface-selective angle-resolved photoemission spectroscopy and unveil the electronic nature on the topmost layer of Sr_{2}RuO_{4} crystal, consisting of slightly rotated RuO_{6} octahedrons. The γ band derived from the 4d_{xy} orbital is found to be about three times narrower than that for the bulk. This strongly contrasts with a subtle variation seen in the α and β bands derived from the one-dimensional 4d_{xz/yz}. This anomaly is reproduced by the dynamical mean-field theory calculations, introducing not only the on-site Hubbard interaction but also the significant Hund's coupling. We detect a coherence-to-incoherence crossover theoretically predicted for Hund's metals, which has been recognized only recently. The crossover temperature in the surface is about half that of the bulk, indicating that the naturally generated monolayer of reconstructed Sr_{2}RuO_{4} is extremely correlated and well isolated from the underlying crystal.
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Grigera SA, Borzi R, Slobinsky DG, Gibbs AS, Higashinaka R, Maeno Y, Grigera TS. An intermediate state between the kagome-ice and the fully polarized state in Dy$_2$Ti$_2$O$_7$. PAPERS IN PHYSICS 2015. [DOI: 10.4279/pip.070009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Yamaguchi O, Kawashima A, Shiono A, Maeno Y, Ishikawa R, Masumoto A, Utsugi H, Daito H, Okano T, Murayama Y, Kobayashi K. [Hange-Shashin-to for preventing diarrhea during afatinib therapy]. Gan To Kagaku Ryoho 2015; 42:581-583. [PMID: 25981651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Afatinib is an epidermal growth factor receptor-tyrosine kinase inhibitor(EGFR-TKI). In a randomized phase III study(Lux- Lung 3 study)employing patients harboring EGFR mutations, patients administered afatinib show a significantly longer progression free survival time(PFS)than those administeredcombination chemotherapy comprising cisplatin andpemetrexed . However, most of the patients(95.2%)treatedwith afatinib experiencedd iarrhea. In the present report, 16 patients with EGFR mutations were treatedby afatinib at our institution from May 2014 to December 2014. Twelve patients were administered a diarrhea prevention herbal medicine, Hange-shashin-to. Seven of 12 patients(58%)had no diarrhea during the 28 days of therapy. All 4 of the patients who did not receive Hange-shashin-to experienced diarrhea above Grade 1 within 6 days of starting therapy. The rate of diarrhea differed significantly between the patients receiving and not receiving Hangeshashin- to. In conclusion, preventive administration of Hange-shashin-to may reduce the occurrence of diarrhea during afatinib treatment.
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Otsuka M, Maeno Y, Fukami T, Inoue M, Tagami T, Ozeki T. Developmental considerations for ethanolates with regard to stability and physicochemical characterization of efonidipine hydrochloride ethanolate. CrystEngComm 2015. [DOI: 10.1039/c5ce00751h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efonidipine hydrochloride ethanolate arranges the chloride ion within a basket-type conformation. This distinctive crystal structure would contribute to the improvement of the API's thermal stability.
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Matsumoto T, Maeno Y, Kato H, Seko-Nakamura Y, Monma-Ohtaki J, Ishiba A, Nagao M, Aoki Y. 5-hydroxytryptamine- and dopamine-releasing effects of ring-substituted amphetamines on rat brain: a comparative study using in vivo microdialysis. Eur Neuropsychopharmacol 2014; 24:1362-70. [PMID: 24862256 DOI: 10.1016/j.euroneuro.2014.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 04/06/2014] [Accepted: 04/27/2014] [Indexed: 10/25/2022]
Abstract
Using in vivo microdialysis, a comparative study was conducted to examine the effects of amphetamine-related compounds (methamphetamine, MAP; 3,4-methylenedioxymethamphetamine, MDMA; p-methoxyamphetamine, PMA; p-methoxymethamphetamine, PMMA; 4-methylthioamphetamine, 4-MTA; 3,4,5-trimethoxyamphetamine, TMA; 2,5-dimethoxy-4-iodoamphetamine, DOI) on extracellular levels of serotonin (5-HT) and dopamine (DA). Dialysates were assayed using HPLC equipped with electrochemical detector following i.p. administration with each drug at a dose of 5 mg/kg. MAP was found to drastically and rapidly increase 5-HT and DA levels (870% and 1460%, respectively). PMA, PMMA, and 4-MTA slightly increased DA levels (150-290%) but remarkably increased 5-HT levels (540-900%). In contrast, TMA and DOI caused no detectable changes in levels of both monoamines. We observed that the potent DA-releasing action of MAP was remarkably decreased by introduction of methoxy or methylthio group at the para position (MAP vs. PMMA or 4-MTA), but introduction of two additional adjacent methoxy groups into PMA totally abolished its 5-HT-/DA-releasing action (PMA vs. TMA). In addition, para-mono-substituted compounds inhibited both monoamine oxidase (MAO) enzymes more strongly than other compounds; PMA and 4-MTA exhibited submicromolar IC50 values for MAO-A. On the other hand, TMA scarcely affected the activity of both MAO enzymes as well as extracellular levels of 5-HT and DA. In this comparative study, MDMA, PMA, and 4-MTA functioned similar to PMMA, a typical empathogen; these findings therefore could be helpful in clarifying the psychopharmacological properties of amphetamine-related, empathogenic designer drugs.
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Hicks CW, Brodsky DO, Yelland EA, Gibbs AS, Bruin JAN, Barber ME, Edkins SD, Nishimura K, Yonezawa S, Maeno Y, Mackenzie AP. Strong Increase of Tc of Sr2RuO4 Under Both Tensile and Compressive Strain. Science 2014; 344:283-5. [DOI: 10.1126/science.1248292] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Veenstra CN, Zhu ZH, Raichle M, Ludbrook BM, Nicolaou A, Slomski B, Landolt G, Kittaka S, Maeno Y, Dil JH, Elfimov IS, Haverkort MW, Damascelli A. Spin-orbital entanglement and the breakdown of singlets and triplets in Sr2RuO4 revealed by spin- and angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2014; 112:127002. [PMID: 24724673 DOI: 10.1103/physrevlett.112.127002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Indexed: 06/03/2023]
Abstract
Spin-orbit coupling has been conjectured to play a key role in the low-energy electronic structure of Sr2RuO4. By using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, we directly measure the value of the effective spin-orbit coupling to be 130±30 meV. This is even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz,yz orbitals around the Fermi surface, resulting in a strongly momentum-dependent entanglement of spin and orbital character in the electronic wavefunction. As demonstrated by the spin expectation value ⟨sk⃗·s-k⃗⟩ calculated for a pair of electrons with zero total momentum, the classification of the Cooper pairs in terms of pure singlets or triplets fundamentally breaks down, necessitating a description of the unconventional superconducting state of Sr2RuO4 in terms of these newly found spin-orbital entangled eigenstates.
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Rastovski C, Dewhurst CD, Gannon WJ, Peets DC, Takatsu H, Maeno Y, Ichioka M, Machida K, Eskildsen MR. Anisotropy of the superconducting state in Sr2RuO4. PHYSICAL REVIEW LETTERS 2013; 111:087003. [PMID: 24010467 DOI: 10.1103/physrevlett.111.087003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Indexed: 06/02/2023]
Abstract
Despite intense studies the exact nature of the order parameter in superconducting Sr2RuO4 remains unresolved. We have used small-angle neutron scattering to study the vortex lattice in Sr2RuO4 with the field applied close to the basal plane, taking advantage of the transverse magnetization. We measured the intrinsic superconducting anisotropy between the c axis and the Ru-O basal plane (~60), which greatly exceeds the upper critical field anisotropy (~20). Our result imposes significant constraints on possible models of triplet pairing in Sr2RuO4 and raises questions concerning the direction of the zero spin projection axis.
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Anwar MS, Nakamura T, Yonezawa S, Yakabe M, Ishiguro R, Takayanagi H, Maeno Y. Anomalous switching in Nb/Ru/Sr₂RuO₄ topological junctions by chiral domain wall motion. Sci Rep 2013; 3:2480. [PMID: 23963428 PMCID: PMC6505398 DOI: 10.1038/srep02480] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 08/02/2013] [Indexed: 11/27/2022] Open
Abstract
A spontaneous symmetry breaking in a system often results in domain wall formation. The motion of such domain walls is utilized to realize novel devices like racetrack-memories, in which moving ferromagnetic domain walls store and carry information. Superconductors breaking time reversal symmetry can also form domains with degenerate chirality of their superconducting order parameter. Sr2RuO4 is the leading candidate of a chiral p-wave superconductor, expected to be accompanied by chiral domain structure. Here, we present that Nb/Ru/Sr2RuO4 topological superconducting-junctions, with which the phase winding of order parameter can be effectively probed by making use of real-space topology, exhibit unusual switching between higher and lower critical current states. This switching is well explained by chiral-domain-wall dynamics. The switching can be partly controlled by external parameters such as temperature, magnetic field and current. These results open up a possibility to utilize the superconducting chiral domain wall motion for future novel superconducting devices.
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Hirose A, Maeno Y, Suda K, Fusazaki N, Kado H, Matsuishi T. Serial hemodynamic assessment using Doppler echocardiography in a fetus with left ventricular aneurysm presented as fetal hydrops. J Perinatol 2013; 33:486-9. [PMID: 23719251 DOI: 10.1038/jp.2012.93] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A 22-week fetus presented with a large left ventricular aneurysm, 24 × 21 × 18 mm in size, detected by abnormal four-chamber view, and severe fetal hydrops with pericardial effusion, ascites and skin edema. The aneurysm was thin-walled, hypokinetic, and had enlarged with gestational age, causing compression of the lung. Although the left ventricular function had progressively impaired as expressed by increase in Tei index, hydrops had resolved by 32 weeks of gestation, probably because of maternal digoxin therapy and successful compensation by the right ventricle, as represented by retrograde blood flow in the distal aortic arch via the patent arterial duct. Because of the significant risk of severe cardiorespiratory failure, we transported the mother to a neonatal cardiac surgical center at 38 weeks of gestation. Indeed, the baby showed severe cardiopulmonary failure after birth, showing 100% of cardiothoracic ratio on the chest X-ray film, but was saved by the successful Dor procedure, including surgical resection of the aneurysm at 10 h of life. In this case, serial echocardiographic evaluation can allow us to monitor the hemodynamics and lead to successful postnatal management.
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Veenstra CN, Zhu ZH, Ludbrook B, Capsoni M, Levy G, Nicolaou A, Rosen JA, Comin R, Kittaka S, Maeno Y, Elfimov IS, Damascelli A. Determining the surface-to-bulk progression in the normal-state electronic structure of Sr(2)RuO(4) by angle-resolved photoemission and density functional theory. PHYSICAL REVIEW LETTERS 2013; 110:097004. [PMID: 23496740 DOI: 10.1103/physrevlett.110.097004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Indexed: 06/01/2023]
Abstract
We revisit the normal-state electronic structure of Sr(2)RuO(4) by angle-resolved photoemission spectroscopy with improved data quality, as well as ab initio band structure calculations in the local-density approximation with the inclusion of spin-orbit coupling. We find that the current model of a single surface layer (√2×√2)R45° reconstruction does not explain all detected features. The observed depth-dependent signal degradation, together with the close quantitative agreement with the slab calculations based on the surface crystal structure as determined by low-energy electron diffraction, reveal that-at a minimum-the subsurface layer also undergoes a similar although weaker reconstruction. This model accounts for all features-a key step in understanding the electronic structure-and indicates a surface-to-bulk progression of the electronic states driven by structural instabilities. Finally, we find no evidence for other phases stemming from either topological bulk properties or, alternatively, the interplay between spin-orbit coupling and the broken symmetry of the surface.
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Nakamura S, Maeno Y, Ohara M, Yamamura A, Funahashi Y, Shibata N. Enantioselective Synthesis of Imidazolines with Quaternary Stereocenters by Organocatalytic Reaction of N-(Heteroarenesulfonyl)imines with Isocyanoacetates. Org Lett 2012; 14:2960-3. [DOI: 10.1021/ol301256q] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Sala G, Castelnovo C, Moessner R, Sondhi SL, Kitagawa K, Takigawa M, Higashinaka R, Maeno Y. Magnetic Coulomb fields of monopoles in spin ice and their signatures in the internal field distribution. PHYSICAL REVIEW LETTERS 2012; 108:217203. [PMID: 23003295 DOI: 10.1103/physrevlett.108.217203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Indexed: 06/01/2023]
Abstract
Fractionalization-the breaking up of an apparently indivisible microscopic degree of freedom-is one of the most counterintuitive phenomena in many-body physics. Here we study its most fundamental manifestation in spin ice, the only known fractionalized magnetic compound in 3D: we directly visualize the 1/r(2) magnetic Coulomb field of monopoles that emerge as the atomic magnetic dipoles fractionalize. We analyze the internal magnetic field distribution, relevant for local experimental probes. In particular, we present new zero-field NMR measurements that exhibit excellent agreement with the calculated line shapes, noting that this experimental technique can in principle measure directly the monopole density in spin ice. The distribution of field strengths is captured by a simple analytical form that exhibits a low density of low-field sites-in apparent disagreement with reported muon spin rotation results. Counterintuitively, the density of low-field locations decreases as the local ferromagnetic correlations imposed by the ice rules weaken.
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Carlo JP, Goko T, Gat-Malureanu IM, Russo PL, Savici AT, Aczel AA, MacDougall GJ, Rodriguez JA, Williams TJ, Luke GM, Wiebe CR, Yoshida Y, Nakatsuji S, Maeno Y, Taniguchi T, Uemura YJ. New magnetic phase diagram of (Sr,Ca)2RuO4. NATURE MATERIALS 2012; 11:323-328. [PMID: 22344326 DOI: 10.1038/nmat3236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 12/23/2011] [Indexed: 05/31/2023]
Abstract
High-T(c) cuprates, iron pnictides, organic BEDT and TMTSF, alkali-doped C(60), and heavy-fermion systems have superconducting states adjacent to competing states exhibiting static antiferromagnetic or spin density wave order. This feature has promoted pictures for their superconducting pairing mediated by spin fluctuations. Sr(2)RuO(4) is another unconventional superconductor which almost certainly has a p-wave pairing. The absence of known signatures of static magnetism in the Sr-rich side of the (Ca, Sr) substitution space, however, has led to a prevailing view that the superconducting state in Sr(2)RuO(4) emerges from a surrounding Fermi-liquid metallic state. Using muon spin relaxation and magnetic susceptibility measurements, we demonstrate here that (Sr,Ca)(2)RuO(4) has a ground state with static magnetic order over nearly the entire range of (Ca, Sr) substitution, with spin-glass behaviour in Sr(1.5)Ca(0.5)RuO(4) and Ca(1.5)Sr(0.5)RuO(4). The resulting new magnetic phase diagram establishes the proximity of superconductivity in Sr(2)RuO(4) to competing static magnetic order.
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Stingl C, Perry RS, Maeno Y, Gegenwart P. Symmetry-breaking lattice distortion in Sr₃Ru₂O₇. PHYSICAL REVIEW LETTERS 2011; 107:026404. [PMID: 21797628 DOI: 10.1103/physrevlett.107.026404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Indexed: 05/31/2023]
Abstract
The electronic nematic phase of Sr₃Ru₂O₇ is investigated by high-resolution in-plane thermal expansion measurements in magnetic fields close to 8 T applied at various angles Θ off the c axis. At Θ < 10° we observe a very small (10⁻⁷) lattice distortion which breaks the fourfold in-plane symmetry, resulting in nematic domains with interchanged a and b axis. At Θ ≳ 10° the domains are almost fully aligned and thermal expansion indicates an area-preserving lattice distortion of order 2 × 10⁻⁶ which is likely related to orbital ordering. Since the system is located in the immediate vicinity of a metamagnetic quantum critical end point, the results represent the first observation of a structural relaxation driven by quantum criticality.
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