188 research outputs found

    Line Defects in Molybdenum Disulfide Layers

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    Layered molecular materials and especially MoS2 are already accepted as promising candidates for nanoelectronics. In contrast to the bulk material, the observed electron mobility in single-layer MoS2 is unexpectedly low. Here we reveal the occurrence of intrinsic defects in MoS2 layers, known as inversion domains, where the layer changes its direction through a line defect. The line defects are observed experimentally by atomic resolution TEM. The structures were modeled and the stability and electronic properties of the defects were calculated using quantum-mechanical calculations based on the Density-Functional Tight-Binding method. The results of these calculations indicate the occurrence of new states within the band gap of the semiconducting MoS2. The most stable non-stoichiometric defect structures are observed experimentally, one of which contains metallic Mo-Mo bonds and another one bridging S atoms

    Electrospun interconnected bead-like P2-NaxCoyMn1−yO2 (x = 0.66, y = 0.1) cathode material for stable sodium-ion storage

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    The development of high-rate and long-cycle-life Na-based cathode materials, on par with the performance of commercialized lithium-based cathodes, is crucial to satisfy the recurring surge in energy demand. Here, we report an interconnected bead-like P2-type manganese-based oxide NaxCoyMn1−yO2 (x = 0.66, y = 0.1) synthesized by electrospinning and subsequent heat treatment as a high-rate cathode material for sodium-ion batteries (SIBs). The employed strategy of one-dimensional morphological design with interconnected bead-like particles profusely enhances Na+ diffusion pathways. This layered cathode material exhibits a stable and superior discharge capacity of 180.0 mAh g−1 at 50 mA g−1 compared to a bare cathode material synthesized via the sol–gel process. Further, a high capacity of 78.3 mAh g−1 was achieved, maintaining excellent capacity retention of 85.0% even after 500 insertion/desertion cycles implying robust Na+ storage properties. High-rate tests also revealed promising electrochemical performances at C-rates as high as 5000 mA g−1, affirming the potential of this layered cathode material for high-rate Na+ storage. Additionally, full SIBs assembled with a NaxCoyMn1−yO2 (x = 0.66, y = 0.1) cathode and a carbon nanofiber (CNF) anode exhibited a high cycle performance, retaining 96.3 mAh g−1 after 100 cycles at 300 mA g−1

    Should patients with kearns-sayre syndrome and corneal endothelial failure be genotyped for a TCF4 trinucleotide repeat, commonly associated with fuchs endothelial corneal dystrophy?

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    The aim of this study was to describe the ocular phenotype in a case with Kearns-Sayre syndrome (KSS) spectrum and to determine if corneal endothelial cell dysfunction could be attributed to other known distinct genetic causes. Herein, genomic DNA was extracted from blood and exome sequencing was performed. Non-coding gene regions implicated in corneal endothelial dystrophies were screened by Sanger sequencing. In addition, a repeat expansion situated within an intron of TCF4 (termed CTG18.1) was genotyped using the short tandem repeat assay. The diagnosis of KSS spectrum was based on the presence of ptosis, chronic progressive external ophthalmoplegia, pigmentary retinopathy, hearing loss, and muscle weakness, which were further supported by the detection of ~6.5 kb mtDNA deletion. At the age of 33 years, the proband’s best corrected visual acuity was reduced to 0.04 in the right eye and 0.2 in the left eye. Rare ocular findings included marked corneal oedema with central corneal thickness of 824 and 844 ”m in the right and left eye, respectively. No pathogenic variants in the genes, which are associated with corneal endothelial dystrophies, were identified. Furthermore, the CTG18.1 genotype was 12/33, which exceeds a previously determined critical threshold for toxic RNA foci appearance in corneal endothelial cells

    Explaining Myanmar's Regime Transition: The Periphery is Central

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    In 2010, Myanmar (Burma) held its first elections after 22 years of direct military rule. Few compelling explanations for this regime transition have emerged. This article critiques popular accounts and potential explanations generated by theories of authoritarian ‘regime breakdown’ and ‘regime maintenance’. It returns instead to the classical literature on military intervention and withdrawal. Military regimes, when not terminated by internal factionalism or external unrest, typically liberalise once they feel they have sufficiently addressed the crises that prompted their seizure of power. This was the case in Myanmar. The military intervened for fear that political unrest and ethnic-minority separatist insurgencies would destroy Myanmar’s always-fragile territorial integrity and sovereignty. Far from suddenly liberalising in 2010, the regime sought to create a ‘disciplined democracy’ to safeguard its preferred social and political order twice before, but was thwarted by societal opposition. Its success in 2010 stemmed from a strategy of coercive state-building and economic incorporation via ‘ceasefire capitalism’, which weakened and co-opted much of the opposition. Having altered the balance of forces in its favour, the regime felt sufficiently confident to impose its preferred settlement. However, the transition neither reflected total ‘victory’ for the military nor secured a genuine or lasting peace

    Types, obstacles and sources of empowerment in co-design: the role of shared material objects and processes

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    Co-design is intrinsically linked to the notion of empowerment, however little research has focussed specifically on understanding the types, obstacles and sources of empowerment in co-design. This paper combines theoretical investigations with observations derived from co-designed research by academic and non-academic partners to explore these issues, in particular, the role of shared material objects and processes in supporting empowerment during co-design. The paper uses the notions of ‘power over,’ ‘power to’, ‘power with’ and ‘power within’ to tease out different aspects of empowerment, and draws on empirical observations to determine different obstacles and sources associated with each. The study therefore makes a theoretical contribution to the understanding of co-design as an empowerment process and should be useful for design researchers undertaking co-design projects with non-experts

    The Importance of Preventive Medicine in Family Practice: A Review of Current Guidelines and Recommendations

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    Prevention is seen as a critical topic in family practice. Primordial prevention, primary prevention, secondary prevention, tertiary prevention, and quaternary prevention are all part of this strategy to disease prevention. To avoid the formation and development of risk factors, primary prevention focuses on addressing the fundamental causes and social determinants of disease. Primary prevention is the practice of preventing illnesses before they arise via the use of treatments such as immunizations and health education. Secondary prevention focuses on illness identification and intervention as early as possible to avoid disease development. Tertiary prevention addresses illness outcomes by restoring health and offering rehabilitation. Finally, quaternary prevention seeks to safeguard patients against needless medical treatments and the harm caused by over-medicating. Risks frequently rise in tandem with frailty and comorbidities. In contrast, advantages frequently drop as life expectancy increases. Preventive management strategies should consider the patient's viewpoint and be mutually agreed upon. Healthcare providers must prioritize the deployment of preventive care services, even when clinical treatments are required, in order to overcome preventive care hurdles. Healthcare practitioners may play a critical role in illness prevention and contribute to family well-being by investing in preventive care and executing these measures

    Enhanced Long-Path Electrical Conduction in ZnO Nanowire Array Devices Grown via Defect-Driven Nucleation

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    Vertical arrays of nanostructures have been widely used as major components in some of the most ground-breaking modern research-based devices, and ZnO nanowires have received particular attention because of their favorable electronic properties. Using a local multiprobe technique to measure the properties of individual ZnO nanowires in vertical arrays, we show for the first time that for metal-catalyzed ZnO nanowire growth the electrical contribution of individual wires to a device is highly dependent on the fate of the catalyst nanoparticle during growth. To overcome the limitations of metal-catalyzed growth, nanowires grown from a defect-driven nucleation process are shown to provide high-quality device structures with excellent long-path electrical conduction

    Sa‘īd b. កasan, biographical notes through the prism of Masālik al-Naáș“ar

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    The Islamic polemical tract Kitāb Masālik al-Naáș“ar reveals much about its author, the Jewish apostate Sa‘īd b. កasan. Sa‘īd plunges into diverse polemic themes, including some with which he is poorly acquainted, and uses sources from all three Abrahamic faiths, showing greater familiarity with Jewish sources than with the Qur’ān. The discussion explores Sa‘īd’s treatment of various issues in Muslim-Jewish polemics through the prism of his important polemical tract, Masālik al-Naáș“ar, and takes one of the first steps toward lifting Sa‘īd out of his undeserved obscurity in scholarship

    Estética urbana: uma anålise através das ideias de ordem, estímulo visual, valor histórico e familiaridade

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    Este artigo examina a dicotomia entre a abordagem da estĂ©tica filosĂłfica e a da estĂ©tica empĂ­rica, assim como os impactos da estĂ©tica formal e da estĂ©tica simbĂłlica, a partir das respostas de usuĂĄrios do espaço urbano de Porto Alegre. SĂŁo investigados os impactos estĂ©ticos causados por cenas urbanas com diferentes nĂ­veis de ordem e estĂ­mulo visual, com e sem valor histĂłrico, e com diferentes nĂ­veis de familiaridade. É tambĂ©m examinada a existĂȘncia ou nĂŁo de diferenças entre as respostas estĂ©ticas de arquitetos, nĂŁo arquitetos com curso superior e pessoas com o primeiro ou segundo grau. Ainda, sĂŁo identificadas as razĂ”es para as avaliaçÔes realizadas por esses trĂȘs grupos. Os principais resultados evidenciam o potencial da estĂ©tica empĂ­rica em explicar as avaliaçÔes estĂ©ticas e revelam o impacto positivo e preponderante da ideia de ordem e estĂ­mulo visual em tais avaliaçÔes
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