188 research outputs found
Line Defects in Molybdenum Disulfide Layers
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-NaxCoyMn1âyO2 (x = 0.66, y = 0.1) cathode material for stable sodium-ion storage
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 NaxCoyMn1âyO2 (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 gâ1 at 50 mA gâ1 compared to a bare cathode material synthesized via the solâgel process. Further, a high capacity of 78.3 mAh gâ1 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 gâ1, affirming the potential of this layered cathode material for high-rate Na+ storage. Additionally, full SIBs assembled with a NaxCoyMn1âyO2 (x = 0.66, y = 0.1) cathode and a carbon nanofiber (CNF) anode exhibited a high cycle performance, retaining 96.3 mAh gâ1 after 100 cycles at 300 mA gâ1
Ethnic armies and ethnic conflict in Burma â Reconsidering the history of colonial militarization in the Kachin region of Burma during the Second World War
Should patients with kearns-sayre syndrome and corneal endothelial failure be genotyped for a TCF4 trinucleotide repeat, commonly associated with fuchs endothelial corneal dystrophy?
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 probandâs 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
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 âregime breakdownâ and âregime maintenanceâ. 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 Myanmarâs always-fragile territorial integrity and sovereignty. Far from suddenly liberalising in 2010, the regime sought to create a âdisciplined democracyâ 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 âceasefire capitalismâ, 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 âvictoryâ 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
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 âpower over,â âpower toâ, âpower withâ and âpower withinâ 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
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
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
SaâÄ«d b. កasan, biographical notes through the prism of MasÄlik al-Naáșar
The Islamic polemical tract KitÄb MasÄlik al-Naáșar reveals much about its author, the Jewish apostate SaâÄ«d b. កasan. SaâÄ«d 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 QurâÄn. The discussion explores SaâÄ«dâs treatment of various issues in Muslim-Jewish polemics through the prism of his important polemical tract, MasÄlik al-Naáșar, and takes one of the first steps toward lifting SaâÄ«d out of his undeserved obscurity in scholarship
EstĂ©tica urbana: uma anĂĄlise atravĂ©s das ideias de ordem, estĂmulo visual, valor histĂłrico e familiaridade
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. Ă 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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