167 research outputs found

    A cascading nonlinear magneto-optical effect in topological insulators

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    Topological insulators (TIs) are characterized by possessing metallic (gapless) surface states and a finite band-gap state in the bulk. As the thickness of a TI layer decreases down to a few nanometers, hybridization between the top and bottom surfaces takes place due to quantum tunneling, consequently at a critical thickness a crossover from a 3D-TI to a 2D insulator occurs. Although such a crossover is generally accessible by scanning tunneling microscopy, or by angle-resolved photoemission spectroscopy, such measurements require clean surfaces. Here, we demonstrate that a cascading nonlinear magneto-optical effect induced via strong spin-orbit coupling can examine such crossovers. The helicity dependence of the time-resolved Kerr rotation exhibits a robust change in periodicity at a critical thickness, from which it is possible to predict the formation of a Dirac cone in a film several quintuple layers thick. This method enables prediction of a Dirac cone using a fundamental nonlinear optical effect that can be applied to a wide range of TIs and related 2D materials

    Diagnostic utility of C-reactive Protein combined with brain natriuretic peptide in acute pulmonary edema: a cross sectional study

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    Introduction Discriminating acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) from cardiogenic pulmonary edema (CPE) using the plasma level of brain natriuretic peptide (BNP) alone remains controversial. The aim of this study was to determine the diagnostic utility of combination measurements of BNP and C-reactive protein (CRP) in critically ill patients with pulmonary edema

    A passively Q-switched compact Er:Lu2O3 ceramics laser at 2.8 μm with a graphene saturable absorber

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    We have demonstrated a passively Q-switched Er:Lu2O3 ceramics laser using a monolayer graphene saturable absorber (SA). Stable pulsed operation with watt-level average power was achieved by a compact linear cavity without focusing on the SA. This is the first demonstration of a passively Q-switched mid-IR Er:Lu2O3 laser using a graphene SA. A maximum pulse energy of 9.4 μJ and a peak power of 33 W were achieved with a 247 ns pulse duration. To our knowledge, this is the shortest pulse duration, highest pulse energy, and highest peak power obtained with a graphene SA in the 3 μm wavelength region

    Distinctive detection of insulinoma using [¹⁸F]FB(ePEG12)12-exendin-4 PET/CT

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    Specifying the exact localization of insulinoma remains challenging due to the lack of insulinoma-specific imaging methods. Recently, glucagon-like peptide-1 receptor (GLP-1R)-targeted imaging, especially positron emission tomography (PET), has emerged. Although various radiolabeled GLP-1R agonist exendin-4-based probes with chemical modifications for PET imaging have been investigated, an optimal candidate probe and its scanning protocol remain a necessity. Thus, we investigated the utility of a novel exendin-4-based probe conjugated with polyethylene glycol (PEG) for [¹⁸F]FB(ePEG12)12-exendin-4 PET imaging for insulinoma detection. We utilized [¹⁸F]FB(ePEG12)12-exendin-4 PET/CT to visualize mouse tumor models, which were generated using rat insulinoma cell xenografts. The probe demonstrated high uptake value on the tumor as 37.1 ± 0.4%ID/g, with rapid kidney clearance. Additionally, we used Pdx1-Cre;Trp53R172H;Rbf/f mice, which developed endogenous insulinoma and glucagonoma, since they enabled differential imaging evaluation of our probe in functional pancreatic neuroendocrine neoplasms. In this model, our [¹⁸F]FB(ePEG12)12-exendin-4 PET/CT yielded favorable sensitivity and specificity for insulinoma detection. Sensitivity: 30-min post-injection 66.7%, 60-min post-injection 83.3%, combined 100% and specificity: 30-min post-injection 100%, 60-min post-injection 100%, combined 100%, which was corroborated by the results of in vitro time-based analysis of internalized probe accumulation. Accordingly, [¹⁸F]FB(ePEG12)12-exendin-4 is a promising PET imaging probe for visualizing insulinoma

    Mirror-symmetric Magneto-optical Kerr Rotation using Visible Light in [(GeTe)2(Sb2Te3)1]n Topological Superlattices

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    Interfacial phase change memory (iPCM), that has a structure of a superlattice made of alternating atomically thin GeTe and Sb2Te3 layers, has recently attracted attention not only due to its superior performance compared to the alloy of the same average composition in terms of energy consumption but also due to its strong response to an external magnetic field (giant magnetoresistance) that has been speculated to arise from switching between topological insulator (RESET) and normal insulator (SET) phases. Here we report magneto-optical Kerr rotation loops in the visible range, that have mirror symmetric resonances with respect to the magnetic field polarity at temperatures above 380 K when the material is in the SET phase that has Kramers-pairs in spin-split bands. We further found that this threshold temperature may be controlled if the sample was cooled in a magnetic field. The observed results open new possibilities for use of iPCM beyond phase-change memory applications

    Commuting quantum transfer matrix approach to intrinsic Fermion system: Correlation length of a spinless Fermion model

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    The quantum transfer matrix (QTM) approach to integrable lattice Fermion systems is presented. As a simple case we treat the spinless Fermion model with repulsive interaction in critical regime. We derive a set of non-linear integral equations which characterize the free energy and the correlation length of for arbitrary particle density at any finite temperatures. The correlation length is determined by solving the integral equations numerically. Especially in low temperature limit this result agrees with the prediction from conformal field theory (CFT) with high accuracy.Comment: 17 page

    Epidemiology of potentially inappropriate medication use in elderly patients in Japanese acute care hospitals.

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    [Purpose]The elderly receive many medications which may have adverse effects. Little evidence is available about the epidemiology of potentially inappropriate medications being prescribed to the elderly in Japan as defined by the Beers criteria, or whether or not these medications result in harm when used in this population. [Methods]We conducted a prospective cohort study of patients aged ≥65 years who were admitted to three acute care hospitals in Japan. Trained research nurses followed up patients from randomly selected wards and collected data about their medications and all potential adverse drug events (ADEs). Two independent reviewers evaluated all the data. The use of potentially inappropriate medications and their effects on patients were identified using the updated Beers criteria. [Results]A total of 2155 elderly patients were eligible; 56.1% received at least one drug listed in the Beers criteria (BL drug). The rates of BL drug prescriptions were 103.8 per 100 admissions and 53.7 per 1000 patient-days, and the incidence rate of ADEs related to BL drugs was 1.7 per 100 BL drug prescriptions. Among patients aged ≥65 years, relatively younger patients (p = 0.0002) and those with less complications (p = 0.04) were likely to be prescribed BL drugs. [Conclusions]Although BL drugs were frequently prescribed to elderly Japanese inpatients, the incidence of related ADEs appeared infrequent. These data suggest that re-evaluation of the appropriateness of the Beers criteria is needed before they are used in Japan and other nations to assess quality or for decision support

    Вклад А.А.Вагина в развитие советской методики преподавания истории

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    В работе рассматривается вклад ученого-методиста Алексея Алексеевича Вагина в развитие советской методики преподавания истории в общеобразовательных школах
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