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Twin theories, polytope mutations and quivers for GTPs
No full textWe propose a unified perspective on two sets of objects that usually arise in the study of bipartite field theories. Each of the sets consists of a polytope, or equivalently a toric Calabi-Yau, and a quiver theory. We refer to the two sets of objects as original and twin. In the simplest cases, the two sides of the correspondence are connected by the graph operation known as untwisting. The democratic treatment that we advocate raises new questions regarding the connections between these objects, some of which we explore.
With this motivation in mind, we establish a correspondence between the mutations of the original polytope and the twin quiver. This leads us to propose that non-toric twin quivers are naturally associated to generalized toric polygons (GTPs) and we explore various aspects of this idea. Supporting evidence includes global symmetries, the ability of twin quivers to encode the generalized s-rule, and the connection between the mutations of polytopes and of configurations of webs of 5-branes suspended from 7-branes. We introduce three methods for constructing twin quivers for GTPs. We also investigate the connection between twin quivers obtained using different toric phases. Twin quivers provide a powerful new perspective on GTPs. The ideas presented in this paper may represent a step towards the generalization of brane tilings to GTPs
Engineering the Local Atomic Configuration in 2H TMDs for Efficient Electrocatalytic Hydrogen Evolution
No full textThe introduction of heteroatoms is a widely employedstrategy forelectrocatalysis of transition metal dichalcogenides (TMDs). Thisapproach activates the inactive basal plane, effectively boostingthe intrinsic catalytic activity. However, the effect of atomic configurationsincorporated within the TMDs' lattice on catalytic activityis not thoroughly understood owing to the lack of controllable syntheticapproaches for highly doped TMDs. In this study, we demonstrate afacile approach to realizing heavily doped MoS2 with ahigh doping concentration above 16% via intermediate-reaction-mediatedchemical vapor deposition. As the V doping concentration increased,the incorporated V atoms coalesced in a manner that enabled both thebasal plane activation and electrical conductivity enhancement ofMoS(2). This accelerated the kinetics of the hydrogen evolutionreaction (HER) through the reduced Gibbs free energy of hydrogen adsorption,as evidenced by experimental and theoretical analyses. Consequently,the coalesced V-doped MoS2 exhibited superior HER performance,with an overpotential of 100 mV at 10 mA cm(-2), surpassingthe pristine and single-atom-doped counterparts. This study providesan intriguing pathway for engineering the atomic doping configurationof TMDs to develop efficient 2D nanomaterial-based electrocatalysts
Evidence of Zintl Intermediate Phase and Its Impacts on Li and Na Storage Performance of Pb-Based Alloying Anodes
No full textAnodematerials based on conversion and alloying reactions arepromising to achieve high energy density of advanced sodium-ion batteries(SIBs). While the chemical similarities between sodium and lithiumas alkali elements make the benchmarking strategy practical in developingnew high-performance anodes, simply borrowing the anode material fromone system to the other does not always guarantee success unless itis based on sound understanding of both Li- and Na-reaction mechanisms.In this work, we report the Na storage performance of a Pb-based anodeand its fundamental reaction dynamics. In contrast to its excellentelectrochemical performances in Li cells (reversible similar to 600 mAh/g),the newly developed Pb@PbO-C nanocomposite anode has limitedelectrochemical Na reaction properties showing moderate capacity andrate performances (similar to 300 mAh/g at 20 mA/g). Synchrotron-basedX-ray diffraction and absorption spectroscopy studies reveal the fundamentaldifferences in the Na and Li reaction mechanism of the Pb-based anode.Unlike Li reaction, the unique Na reaction mechanism involves theformation of a highly ionic NaPb Zintl phase, which comprises tetrahedralPb(4) clusters, as an intermediate phase. The strong covalentcharacter of the Pb-4 Zintl clusters adversely affects theelectronic conductivity and thus limits the electrochemical performanceof the Pb-based anode in Na cells. These findings provide new insightsapplicable to developing high-performance alloying anode materials
Materials, Device Structures, and Applications of Flexible Perovskite Light-Emitting Diodes
No full textThe flexible type of displays, which can alter their shape freely (e.g., bendable or foldable displays) according to situational demands, is under an intense spotlight due to applications in human-friendly mobile electronics. Among various types of light-emitting diodes (LEDs), meanwhile, perovskite-based LEDs (PeLEDs) have garnered particular attention in recent years as next-generation optoelectronic devices due to their exceptional optical characteristics, such as high efficiency (up to theoretical limits), high color purity, wide color gamut over the entire visible range, and ultrathin form factor. By integrating perovskite materials on an ultrathin flexible substrate with a proper encapsulation layer, the flexible PeLEDs, which can conform to various curved surfaces and be stably operated in an ambient condition, have been developed. Here, recent advances of the flexible PeLEDs are reviewed. First, light-emitting materials and device structures for the PeLEDs are introduced. Then, research progress on the flexible PeLEDs, either with and without the encapsulation layer are summarized. Next, some representative application examples of the flexible PeLEDs are briefly discussed. Finally, this review includes a brief discussion on future prospects
Simple Coacervation of Guanidinium-Containing Polymers Induced by Monovalent Salt
No full textLiquid-liquid phase separation (LLPS) of macromolecules,called coacervation, is induced by non-covalent intermolecular associationsin aqueous solutions, which is frequently observed in biological processesincluding cellular compartmentation, signaling, and regulation. Recently,associative interactions between pi-conjugated residues haveemerged to induce LLPS, along with electrostatic interaction. An arginineresidue having a positively charged guanidinium group plays a pivotalrole in protein phase behavior because the orientational amphiphilicityof guanidinium groups allows face-to-face pi-pi stackingdespite Coulombic repulsion. In this study, we investigate the simplecoacervates of guanidinium-functionalized polyelectrolytes (i.e., poly-arginine) in aqueous media as a function of saltconcentration, salt type, and temperature to understand the exclusiverole of pi-conjugated moieties. Contrary to ammonium-functionalizedpolyelectrolyte (i.e., poly-lysine) solutions, guanidinium-functionalizedpolyelectrolyte solutions become turbid by adding monovalent saltsand exhibit the upper critical solution temperature (UCST) behavior;the critical temperature is harnessed by salt concentration and salttype. Although a pi-pi stacked guanidinium pair canexist at a lower salt concentration, LLPS occurs when the number ofintermolecular guanidinium pairs goes beyond a critical value to producethe network structure. Furthermore, the enthalpically favored pi-pi interaction directly affects the bulk rheological behavior and theinterfacial property of the coacervates. Our findings provide insightsinto the underlying interactions of protein phase separation and shednew light on the critical role of pi-pi stackingin the biological process and material design
Use of coal bottom ash for the production of sodium silicate solution in metakaolin-based geopolymers concerning environmental load reduction
No full textThis research proposes applying coal bottom ash (CBA) to metakaolin-based geopolymers. The conventional CBA mixing method in geopolymers degrades the compressive strength of the geopolymers mainly because of the low reactivity of CBA. To minimize the strength degradation and maximize the available CBA content in geo-polymers, the CBA was treated with an alkaline solution and then mixed with metakaolin. A sodium hydroxide solution with 10 and 12 M concentrations, a water-to-solid ratio of 0.50, and curing at ambient temperature were used for all geopolymer composites. If replaced with CBA up to 15% of the total weight of the geopolymer, the proposed method can not only yield a higher compressive strength than the conventional mixing method by providing external silicon from the CBA, but it can also show compressive strength similar to a typical geo-polymer without CBA. The properties observed by XRD, FT-IR, SEM/EDS, and MIP disclose the reasons for the proposed method accommodating a larger amount of CBA
Phospholipases in Gliomas: Current Knowledge and Future Perspectives from Bench to Bedside
No full textPhospholipases are essential intermediaries that work as hydrolyzing enzymes of phospholipids (PLs), which represent the most abundant species contributing to the biological membranes of nervous cells of the healthy human brain. They generate different lipid mediators, such as diacylglycerol, phosphatidic acid, lysophosphatidic acid, and arachidonic acid, representing key elements of intra- and inter-cellular signaling and being involved in the regulation of several cellular mechanisms that can promote tumor progression and aggressiveness. In this review, it is summarized the current knowledge about the role of phospholipases in brain tumor progression, focusing on low- and high-grade gliomas, representing promising prognostic or therapeutic targets in cancer therapies due to their influential roles in cell proliferation, migration, growth, and survival. A deeper understanding of the phospholipases-related signaling pathways could be necessary to pave the way for new targeted therapeutic strategies
Brand Exploration in Metaverse: Effects of Avatar Resemblance on Brand Attitude
No full textA ???brand??? metaverse is a virtual space where customers experience the brand via digital avatars. With the advancement of augmented and virtual reality technologies, a brand metaverse is an important medium for communicating the brand with customers. In this study, we focus on the resemblance between a customer???s self and his/her avatar (i.e., self-avatar resemblance) in the brand metaverse and examine its influence on brand attitude. Prior studies examine self-avatar resemblance exclusively in non-brand related virtual gaming platforms and test its effects on identity perception and immersion in the platforms. However, few studies probe the extent to which self-avatar resemblance influences customers??? exploration in a brand metaverse and their attitude toward the brand. We fill this research gap by uncovering the positive effects of self-avatar resemblance on brand attitude and purchase intentions. Moreover, we proffer that attitude toward the brand metaverse platform mediates the relationship between self-avatar resemblance and brand attitude. In addition, based on the interactive nature of metaverse, we hypothesize copresence???the number of avatars exploring the brand metaverse at the same time???to be a moderator which strengthens the mediation. We conduct an experiment using a fashion brand???s virtual world positioned in a popular metaverse platform. In this experiment, participants create an avatar and freely roam around in the brand metaverse with their avatar. By reviewing the screen recording of each participant???s brand exploration in the metaverse, we measure self-avatar resemblance and other constructs. We also collect responses from questionnaires designed to measure attitudinal and behavioral variables. With the accumulated data, we test the hypotheses using partial least square structural equation model and find the results largely consistent with the hypotheses. With the findings, we provide important and interesting implications to marketing practitioners considering and doing ???metaverse marketing.??