806 research outputs found

    Holographic Meson Spectra in the Dense Medium with Chiral Condensate

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    We study two 1/Nc1/N_c effects on the meson spectra by using the AdS/CFT correspondence where the 1/Nc1/N_c corrections from the chiral condensate and the quark density are controlled by the gravitational backreaction of the massive scalar field and U(1) gauge field respectively. The dual geometries with zero and nonzero current quark masses are obtained numerically. We discuss meson spectra and binding energy of heavy quarkonium with the subleading corrections in the hard wall model.Comment: 16 pages, 4 figure

    Non-monotonic temperature dependent transport in graphene grown by Chemical Vapor Deposition

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    Temperature-dependent resistivity of graphene grown by chemical vapor deposition (CVD) is investigated. We observe in low mobility CVD graphene device a strong insulating behavior at low temperatures and a metallic behavior at high temperatures manifesting a non-monotonic in the temperature dependent resistivity.This feature is strongly affected by carrier density modulation. To understand this anomalous temperature dependence, we introduce thermal activation of charge carriers in electron-hole puddles induced by randomly distributed charged impurities. Observed temperature evolution of resistivity is then understood from the competition among thermal activation of charge carriers, temperature-dependent screening and phonon scattering effects. Our results imply that the transport property of transferred CVD-grown graphene is strongly influenced by the details of the environmentComment: 7 pages, 3 figure

    Paleoparasitological Studies on Mummies of the Joseon Dynasty, Korea

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    Paleoparasitology is the application of conventional or molecular investigative techniques to archeological samples in order to reveal parasitic infection patterns among past populations. Although pioneering studies already have reported key paleoparasitological findings around the world, the same sorts of studies had not, until very recently, been conducted in sufficient numbers in Korea. Mummified remains of individuals dating to the Korean Joseon Dynasty actually have proved very meaningful to concerned researchers, owing particularly to their superb preservation status, which makes them ideal subjects for paleoparasitological studies. Over the past several years, our study series on Korean mummies has yielded very pertinent data on parasitic infection patterns prevailing among certain Joseon Dynasty populations. In this short review, we summarized the findings and achievements of our recent paleoparasitological examinations of Joseon mummies and discussed about the prospects for future research in this vein

    Paleoparasitological Studies on Mummies of the Joseon Dynasty, Korea

    Get PDF
    Paleoparasitology is the application of conventional or molecular investigative techniques to archeological samples in order to reveal parasitic infection patterns among past populations. Although pioneering studies already have reported key paleoparasitological findings around the world, the same sorts of studies had not, until very recently, been conducted in sufficient numbers in Korea. Mummified remains of individuals dating to the Korean Joseon Dynasty actually have proved very meaningful to concerned researchers, owing particularly to their superb preservation status, which makes them ideal subjects for paleoparasitological studies. Over the past several years, our study series on Korean mummies has yielded very pertinent data on parasitic infection patterns prevailing among certain Joseon Dynasty populations. In this short review, we summarized the findings and achievements of our recent paleoparasitological examinations of Joseon mummies and discussed about the prospects for future research in this vein

    Plasma-Induced Frequency Chirp of Intense Femtosecond Lasers and Its Role in Shaping High-Order Harmonic Spectral Lines

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    We investigate the self-phase modulation of intense femtosecond laser pulses propagating in an ionizing gas and its effects on collective properties of high-order harmonics generated in the medium. Plasmas produced in the medium are shown to induce a positive frequency chirp on the leading edge of the propagating laser pulse, which subsequently drives high harmonics to become positively chirped. In certain parameter regimes, the plasma-induced positive chirp can help to generate sharply peaked high harmonics, by compensating for the dynamically-induced negative chirp that is caused by the steep intensity profile of intense short laser pulses.Comment: 5 pages, 5 figure

    Attenuating the EGFR-ERK-SOX9 axis promotes liver progenitor cell‐mediated liver regeneration in zebrafish

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    The liver is a highly regenerative organ, but its regenerative capacity is compromised in severe liver injury settings. In chronic liver diseases, the number of liver progenitor cells (LPCs) correlates proportionally to disease severity, implying that their inefficient differentiation into hepatocytes exacerbates the disease. Moreover, LPCs secrete pro‐inflammatory cytokines; thus, their prolonged presence worsens inflammation and induces fibrosis. Promoting LPC‐to‐hepatocyte differentiation in patients with advanced liver disease, for whom liver transplantation is currently the only therapeutic option, may be a feasible clinical approach since such promotion generates more functional hepatocytes and concomitantly reduces inflammation and fibrosis. Here, using zebrafish models of LPC‐mediated liver regeneration, we present a proof‐of‐principle of such therapeutics by demonstrating a role for the EGFR signaling pathway in differentiation of LPCs into hepatocytes. We found that suppression of EGFR signaling promoted LPC‐to‐hepatocyte differentiation via the MEK‐ERK‐SOX9 cascade. Pharmacological inhibition of EGFR or MEK/ERK promoted LPC‐to‐hepatocyte differentiation as well as genetic suppression of the EGFR‐ERK‐SOX9 axis. Moreover, Sox9b overexpression in LPCs blocked their differentiation into hepatocytes. In the zebrafish liver injury model, both hepatocytes and biliary epithelial cells contributed to LPCs. EGFR inhibition promoted the differentiation of LPCs regardless of their origin. Notably, short‐term treatment with EGFR inhibitors resulted in better liver recovery over the long term. Conclusion: The EGFR‐ERK‐SOX9 axis suppresses LPC‐to‐hepatocyte differentiation during LPC‐mediated liver regeneration. We suggest EGFR inhibitors as a pro‐regenerative therapeutic drug for patients with advanced liver disease

    Strongly adhesive dry transfer technique for van der Waals heterostructure

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    That one can stack van der Waals materials with atomically sharp interfaces has provided a new material platform of constructing heterostructures. The technical challenge of mechanical stacking is picking up the exfoliated atomically thin materials after mechanical exfoliation without chemical and mechanical degradation. Chemically inert hexagonal boron nitride (hBN) has been widely used for encapsulating and picking up vdW materials. However, due to the relatively weak adhesion of hBN, assembling vdW heterostructures based on hBN has been limited. We report a new dry transfer technique. We used two vdW semiconductors (ZnPS3 and CrPS4) to pick up and encapsulate layers for vdW heterostructures, which otherwise are known to be hard to fabricate. By combining with optimized polycaprolactone (PCL) providing strong adhesion, we demonstrated various vertical heterostructure devices, including quasi-2D superconducting NbSe2 Josephson junctions with atomically clean interface. The versatility of the PCL-based vdW stacking method provides a new route for assembling complex 2D vdW materials without interfacial degradation.Comment: Accepted for publication in 2D Material

    Primary intraosseous carcinoma in the pediatric and adolescent mandible

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    Abstract Background Primary intraosseous carcinoma (PIOC) is a rare malignant odontogenic tumor that predominantly occurs in males older than 50 years. PIOC can be misdiagnosed as odontogenic cyst because it occasionally shows a well-defined border on radiography. In this study, related literatures of pediatric and adolescent PIOC cases were analyzed under strict PRISMA guidelines along with an adolescent case who was provisionally misdiagnosed as an odontogenic cyst. Methods All case reports for PIOC published in English from 1966 to 2021 were collected. Cases under the age of 20 were classified as pediatric and adolescent populations in this study. A total of 12 pediatric and adolescent cases including 11 PIOCs from the literature and one new case of a 14-year-old female were analyzed. Clinical and radiographic features, diagnosis and treatment approaches, and prognosis were investigated. Results Ages ranged from 4 to 18 years. The female to male ratio was 1.4:1. Seven cases occurred in the mandible. Swelling was observed in 11 patients. The radiologic borders were well-defined in six cases and corticated in four cases. Tooth displacement and root resorption were observed in four and six cases, respectively. The provisional diagnosis for seven patients was odontogenic cyst and enucleation was performed in six cases including the new case. During the follow-up period, local recurrence occurred in three patients. The pediatric and adolescent PIOC cases with local recurrence showed poor prognosis. The locally recurred lesion in the new case did not decrease in size despite concurrent chemo-radiation therapy. Conclusions Three-dimensional imaging modalities and incisional biopsy with multiple specimens are necessary to rule out PIOC in the lesions with atypical radiographic findings. PIOC should be diagnosed differentially from odontogenic cyst even in pediatric and adolescent populations to properly manage the disease with poor prognosis

    An iterative approach to Large-N case studies: insights from qualitative analysis of quantitative inconsistencies

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    Large-N comparative studies have helped common pool resource scholars gain general insights into the factors that influence collective action and governance outcomes. However, these studies are often limited by missing data, and suffer from the methodological limitation that important information is lost when we reduce textual information to quantitative data. This study was motivated by nine case studies that appeared to be inconsistent with the expectation that the presence of Ostrom’s Design Principles increases the likelihood of successful common pool resource governance. These cases highlight the limitations of coding and analysing Large-N case studies. We examine two issues: 1) the challenge of missing data and 2) potential approaches that rely on context (which is often lost in the coding process) to address inconsistencies between empirical observations theoretical predictions. For the latter, we conduct a post-hoc qualitative analysis of a large-N comparative study to explore 2 types of inconsistencies: 1) cases where evidence for nearly all design principles was found, but available evidence led to the assessment that the CPR system was unsuccessful and 2) cases where the CPR system was deemed successful despite finding limited or no evidence for design principles. We describe inherent challenges to large-N comparative analysis to coding complex and dynamically changing common pool resource systems for the presence or absence of design principles and the determination of “success”. Finally, we illustrate how, in some cases, our qualitative analysis revealed that the identity of absent design principles explained inconsistencies hence de-facto reconciling such apparent inconsistencies with theoretical predictions. This analysis demonstrates the value of combining quantitative and qualitative analysis, and using mixed-methods approaches iteratively to build comprehensive methodological and theoretical approaches to understanding common pool resource governance in a dynamically changing context
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