1,260 research outputs found

    Defect Motion and Lattice Pinning Barrier in Josephson-Junction Ladders

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    We study motion of domain wall defects in a fully frustrated Josephson-unction ladder system, driven by small applied currents. For small system sizes, the energy barrier E_B to the defect motion is computed analytically via symmetry and topological considerations. More generally, we perform numerical simulations directly on the equations of motion, based on the resistively-shunted junction model, to study the dynamics of defects, varying the system size. Coherent motion of domain walls is observed for large system sizes. In the thermodynamical limit, we find E_B=0.1827 in units of the Josephson coupling energy.Comment: 7 pages, and to apear in Phys. Rev.

    Potential identity of multi-potential cancer stem-like subpopulation after radiation of cultured brain glioma

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    <p>Abstract</p> <p>Background</p> <p>Glioblastoma multiforme (GBM) is the most frequently encountered brain cancer. Although the existence of cancer stem cells in GBM has been previously established, there is little evidence to explain the difference between cancer stem cells and radio-resistant cells in GBM. In an effort to increase our understanding of whether cellular radio-resistance is a characteristic associated with cancer stem cells, we developed a dissociated cell system of subpopulations derived from GBM, and demonstrated radiotherapy resistance therein.</p> <p>Results</p> <p>The radio-resistant cancer cell subpopulations of GBM abundantly express CD133, CD117, CD71, and CD45 surface markers, and these radio-resistant cancer cell subpopulations have the capacity for extensive proliferation, self-renewal, and pluripotency. These radio-resistant cancer subpopulations have been shown to initiate tumorigenesis when transplanted into SCID mouse brains. Moreover, these tumors evidenced highly peculiar nest-like shapes harboring both vascular and cancerous tissue structures, which expressed the blood vessel specific marker, the von Willebrand factor. Accordingly, subpopulations of radio-resistant cells in GBM have been shown to be very similar to hematopoietic stem cells (HSCs) in the circulating blood. This similarity may contribute to increased tumor growth and GBM recurrence.</p> <p>Conclusion</p> <p>The results of the present study provide further evidence for radio resistant subpopulations of cancer stem cells in GBM. Also, our results will assist in the identification and characterization of cancer stem cell populations in glioma, and will help to improve the therapeutic outcomes of GBM.</p

    Glutaminase 1 inhibition reduces thymidine synthesis in NSCLC

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    AbstractWe found that non-small cell lung cancer (NSCLC) is remarkably sensitive to the regulation of glutamine supply by testing the metabolic dependency of 11 cancer cell lines against regulation of glycolysis, autophagy, fatty acid synthesis, and glutamine supply. Glutamine is known as a key supplement of cancer cell growth that is converted to α-ketoglutarate for anabolic biogenesis via glutamate by glutaminase 1 (GLS1). GLS1 inhibition using 10 μM of bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) showed about 50% cell growth arrest by SRB assay. By testing the synergistic effects of conventional therapeutics, BPTES combined with 5-fluorouracil (5-FU), an irreversible inhibitor of thymidylate synthase, significant effects were observed on cell growth arrest in NSCLC. We found that GLS1 inhibition using BPTES reduced metabolic intermediates including thymidine and carbamoyl phosphate. Reduction of thymidine and carbamoyl-phosphate synthesis by BPTES treatment exacerbated pyrimidine supply by combination with 5-FU, which induced cell death synergistically in NSCLC

    Spectroscopic ellipsometry and absorption study of Zn1-xMnxO/Al2O3 (0 \u3c= x \u3c= 0.08) thin films

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    We grow Zn1−xMnxO∕Al2O3 (0⩽x⩽0.08)thin films on sapphire (0001) using radio-frequency sputtering deposition method with Ar and various N2 flow rates. We examine the effect of N2 codoping on the band gap and Mn-related midgap absorption of (Zn,Mn)O. Using spectroscopic ellipsometry, we measure pseudodielectric functions in the spectral range between 1 and 4.5eV. Using the model of Holden et al. [T. Holden et al., Phys. Rev. B56, 4037 (1997)], we determine the uniaxial (Zn,Mn)O dielectric function and the E0 band-gapenergy. The fitted band gap does not change appreciably with increasing Mn composition up to 2%. We find a very large broadening of both the E0 band gap and its exciton partner E0x peaks even for less than 2% of optically determined Mn composition. In ellipsometric spectra, we also find Mn-related 3eV optical structure. In particular, optical absorption spectra with varying N2 gas flow rate show that the Mn-related peak intensity decreases with increasing N2 flux. The decrease of the 3eV Mn-related peak intensity is attributed to increasing N2 flow rate and Mn–N hybridization

    Pre-set extrusion bioprinting for multiscale heterogeneous tissue structure fabrication

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    Recent advances in three-dimensional bioprinting technology have led to various attempts in fabricating human tissue-like structures. However, current bioprinting technologies have limitations for creating native tissue-like structures. To resolve these issues, we developed a new pre-set extrusion bioprinting technique that can create heterogeneous, multicellular, and multimaterial structures simultaneously. The key to this ability lies in the use of a precursor cartridge that can stably preserve a multimaterial with a pre-defined configuration that can be simply embedded in a syringe-based printer head. The multimaterial can be printed and miniaturized through a micro-nozzle without conspicuous deformation according to the pre-defined configuration of the precursor cartridge. Using this system, we fabricated heterogeneous tissue-like structures such as spinal cords, hepatic lobule, blood vessels, and capillaries. We further obtained a heterogeneous patterned model that embeds HepG2 cells with endothelial cells in a hepatic lobule-like structure. In comparison with homogeneous and heterogeneous cell printing, the heterogeneous patterned model showed a well-organized hepatic lobule structure and higher enzyme activity of CYP3A4. Therefore, this pre-set extrusion bioprinting method could be widely used in the fabrication of a variety of artificial and functional tissues or organs

    Axial Load Testing of Hybrid Concrete Columns Consisting of UHPFRC Tube and Normal-Strength Concrete Core

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    To investigate the axial load behavior of hybrid concrete columns consisting of an ultra-high performance fiber-reinforced concrete tube (20 mm thick, 92.6 MPa or 143.3 MPa) and normal-strength concrete core (28.2 MPa), concentric axial load tests were performed for five column specimens. The UHPFRC tube can function as a form during core-filling and as a cover having high performance at service and ultimate load conditions. Axial loading was applied to the core only, and the tube was indirectly loaded by bearing of transverse threaded bars. Test parameters included the volume fraction of steel fibers, volumetric ratio of transverse bars, and usage of wire-mesh in the tube. Test results showed that structural performance such as initial stiffness, peak load, displacement ductility, and energy absorption capacity varied greatly according to each test parameter. During the course of axial loading applied on the core only, the axial load behavior of the hybrid concrete columns generally corresponded to the full composite action at the initial loading stage and then changed to that of non-composite action (core only) after the failure of the threaded bars.This research was supported by grants from the National Natural Science Foundation of China (Grant No. 51678196) and the Fundamental Research Funds for the Central Universities (Grant No. HIT. NSRIF. 2013112), and the authors are grateful to the authorities for their supports

    Cough persistence in adults with chronic cough: a 4-year retrospective cohort study

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    BackgroundThere is very limited evidence regarding long-term prognosis of chronic cough. We examined longitudinal outcomes among patients with chronic cough, and explored predictors of cough persistence.MethodsA retrospective cohort was constructed of adults who had newly visited a specialist cough clinic in 2012–2013. All had undergone systematic investigation for chronic cough. The Hull Airway Reflux Questionnaire (HARQ) was administered to assess reflux cough symptoms. A follow-up survey was conducted in 2016–2017 to assess cough persistence.ResultsFrom 418 candidates, 323 participated in the follow-up study; main analyses focused on patients with chronic persistent cough (n=64; 19.8%) and remitted cough (n=193; 59.8%). Compared with remitted cough, chronic persistent cough group had more family history of chronic cough (17.2% vs. 4.7%, p=0.001) and cold air-sensitive cough (62.5% vs. 44.6%, p=0.013). The total HARQ score did not differ; however, two items (cough with eating and cough with certain foods) scored significantly higher in chronic persistent cough. In multivariate analyses, a family history of chronic cough (adjusted odds ratio 4.27 [95% confidence interval 1.35-9.89]), cold air-sensitive cough (2.01 [1.09-3.73]), and cough with eating (1.22 [1.02–1.45]) were associated with chronic persistent cough at 4 years.Conclusions Cough persists in about 20% of patients after 4 years following systematic assessment and treatments. Several cough characteristics, such as family history, cold air-sensitivity, or reflux cough, may be associated with cough persistence. Larger cohort studies are warranted to further understand long-term prognosis and confirm predictors of persistence in patients with chronic cough

    Could Fractional Exhaled Nitric Oxide Test be Useful in Predicting Inhaled Corticosteroid Responsiveness in Chronic Cough? A Systematic Review

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    © 2016 Background Fractional exhaled nitric oxide (FENO) is a safe and convenient test for assessing T H 2 airway inflammation, which is potentially useful in the management of patients with chronic cough. Objective To summarize the current evidence on the diagnostic usefulness of FENO for predicting inhaled corticosteroid (ICS) responsiveness in patients with chronic cough. Methods A systematic literature review was conducted to identify articles published in peer-reviewed journals up to February 2015, without language restriction. We included studies that reported the usefulness of FENO (index test) for predicting ICS responsiveness (reference standard) in patients with chronic cough (target condition). The data were extracted to construct a 2 × 2 accuracy table. Study quality was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. Results We identified 5 original studies (2 prospective and 3 retrospective studies). We identified considerable heterogeneities in study design and outcome definitions, and thus were unable to perform a meta-analysis. The proportion of ICS responders ranged from 44% to 59%. Sensitivity and specificity ranged from 53% to 90%, and from 63% to 97%, respectively. The reported area under the curve ranged from abou t 0.60 to 0.87; however, studies with a prospective design and a lower prevalence of asthma had lower area under the curve values. None measured placebo effects or objective cough frequency. Conclusions We did not find strong evidence to support the use of FENO tests for predicting ICS responsiveness in chronic cough. Further studies need to have a randomized, placebo-controlled design, and should use validated measurement tools for cough. Standardization would facilitate the development of clinical evidence

    Taurine in drinking water recovers learning and memory in the adult APP/PS1 mouse model of Alzheimer's disease

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    Alzheimer's disease (AD) is a lethal progressive neurological disorder affecting the memory. Recently, US Food and Drug Administration mitigated the standard for drug approval, allowing symptomatic drugs that only improve cognitive deficits to be allowed to accelerate on to clinical trials. Our study focuses on taurine, an endogenous amino acid found in high concentrations in humans. It has demonstrated neuroprotective properties against many forms of dementia. In this study, we assessed cognitively enhancing property of taurine in transgenic mouse model of AD. We orally administered taurine via drinking water to adult APP/PS1 transgenic mouse model for 6 weeks. Taurine treatment rescued cognitive deficits in APP/PS1 mice up to the age-matching wild-type mice in Y-maze and passive avoidance tests without modifying the behaviours of cognitively normal mice. In the cortex of APP/PS1 mice, taurine slightly decreased insoluble fraction of Aβ. While the exact mechanism of taurine in AD has not yet been ascertained, our results suggest that taurine can aid cognitive impairment and may inhibit Aβ-related damages.MIT International Science and Technology InitiativesKorea Health Industry Development Institute (H14C04660000)Korea Institute of Science and Technology (Open Research 2E24582)Korea Institute of Science and Technology (Flagship 2E25023
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