46 research outputs found

    Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2

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    An abrupt first-order metal-insulator transition (MIT) without structural phase transition is first observed by current-voltage measurements and micro-Raman scattering experiments, when a DC electric field is applied to a Mott insulator VO_2 based two-terminal device. An abrupt current jump is measured at a critical electric field. The Raman-shift frequency and the bandwidth of the most predominant Raman-active A_g mode, excited by the electric field, do not change through the abrupt MIT, while, they, excited by temperature, pronouncedly soften and damp (structural MIT), respectively. This structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure

    Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension

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    OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo

    Minimal Symptom Expression' in Patients With Acetylcholine Receptor Antibody-Positive Refractory Generalized Myasthenia Gravis Treated With Eculizumab

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    The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension

    Concentration gradient generation of multiple chemicals using spatially controlled self-assembly of particles in microchannels

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    We present a robust microfluidic platform for the stable generation of multiple chemical gradients simultaneously using in situ self-assembly of particles in microchannels. This proposed device enables us to generate stable and reproducible diffusion-based gradients rapidly without convection flow: gradients are stabilized within 5 min and are maintained steady for several hours. Using this device, we demonstrate the dynamic position control of bacteria by introducing the sequential directional change of chemical gradients. Green Fluorescent Protein (GFP)-expressing bacterial cells, allowing quantitative monitoring, show not only tracking motion according to the directional control of chemical gradients, but also the gradual loss of sensitivity when exposed to the sequential attractants because of receptor saturation. In addition, the proposed system can be used to study the preferential chemotaxis assay of bacteria toward multiple chemical sources, since it is possible to produce multiple chemical gradients in the main chamber; aspartate induces the most preferential chemotaxis over galactose and ribose. The microfluidic device can be easily fabricated with a simple and cost effective process based on capillary pressure and evaporation for particle assembly. The assembled particles create uniform porous membranes in microchannels and its porosity can be easily controlled with different size particles. Moreover, the membrane is biocompatible and more robust than hydrogel-based porous membranes. The proposed system is expected to be a useful tool for the characterization of bacterial responses to various chemical sources, screening of bacterial cells, synthetic biology and understanding many cellular activities.close10

    Role of the Myristoylation Site in Expressing Exogenous Functional Proteins in Coxsackieviral Vector

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    Usefulness of Procalcitonin in the Diagnosis of Bacterial Infection in Immunocompetent Children

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    Bacterial infections (BIs) need to be differentiated from non-BIs (NBIs) to enable prompt administration of antibiotics. Therefore, inflammatory biomarkers are needed as they can accurately identify BIs. This study evaluated the usefulness of procalcitonin (PCT) in the diagnosis of BI in immunocompetent children. We retrospectively reviewed the medical records of patients <18 years who underwent PCT measurements between July 2012 and June 2019. In total, 474 patients were enrolled and divided into the BI (n = 205) and NBI groups (n = 269). The BI group was subcategorized into the invasive BI (IBI; n = 94), mucosal BI (MBI; n = 31), toxigenic BI (TBI; n = 23), and localized BI (LBI; n = 57) subgroups. The NBI group was further subcategorized into the viral infection (VI; n = 118) and inflammatory disease groups (ID; n = 151). PCT was compared with the levels of C-reactive protein (CRP), white blood cell (WBC), and erythrocyte sedimentation rate (ESR). Between the BI and NBI groups, PCT (4.2 ± 16.9 vs. 1.1 ± 2.5 ng/mL; p = 0.008) and ESR (39.1 ± 32.4 vs. 54.8 ± 28.2 mm/h; p < 0.001) were significantly different. Between the IBI and other groups, WBC (14,797 ± 7148 vs. 12,622 ± 5770 × 106/L; p = 0.007), ESR (35.3 ± 30.3 vs. 51.5 ± 30.3 mm/h; p < 0.001), and PCT (8.1 ± 23.8 vs. 1.0 ± 3.4 ng/mL; p = 0.005) were significantly different. However, none of the biomarkers were useful in differentiating BI from NBI. While WBC (area under curve (AUC) = 0.615, p = 0.003) and PCT (AUC = 0.640, p < 0.001) were useful, they fared poorly in differentiating IBI from other groups. Thus, additional studies are needed to identify more accurate biomarkers capable of differentiating BIs, especially IBIs