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By assuming Vinogradov–Korobov-type zero-free regions and the generalized Ramanujan–Petersson conjecture, we establish nontrivial upper bounds for almost all short sums of Fourier coefficients of Hecke–Maass cusp forms for S L (n , ℤ). As applications, we obtain nontrivial upper bounds for the averages of shifted sums involving coefficients of the Hecke–Maass cusp forms for S L (n , ℤ). Furthermore, we present a conditional result regarding sign changes of these coefficients. [ABSTRACT FROM AUTHOR]

Skeletal muscle connective tissue (MCT) surrounds myofiber bundles to provide structural support, produce force transduction from tendons, and regulate satellite cell differentiation during muscle regeneration. Engineered muscle tissue composed of myofibers layered within MCT has not yet been developed. Herein, a bioengineering strategy to create MCT‐layered myofibers through the development of stem cell fate‐controlling biomaterials that achieve both myogenesis and fibroblast differentiation in a locally controlled manner at the single construct is introduced. The reciprocal role of transforming growth factor‐beta 1 (TGF‐β1) and its inhibitor as well as 3D matrix stiffness to achieve co‐differentiation of MCT fibroblasts and myofibers from a human‐induced pluripotent stem cell (hiPSC)‐derived paraxial mesoderm is studied. To avoid myogenic inhibition, TGF‐β1 is conjugated on the gelatin‐based hydrogel to control the fibroblasts' populations locally; the TGF‐β1 degrades after 2 weeks, resulting in increased MCT‐specific extracellular matrix (ECM) production. The locations of myofibers and fibroblasts are precisely controlled by using photolithography and co‐axial wet spinning techniques, which results in the formation of MCT‐layered functional myofibers in 3D constructs. This advanced engineering strategy is envisioned as a possible method for obtaining biomimetic human muscle grafts for various biomedical applications. [ABSTRACT FROM AUTHOR]

Sodium super ionic conductor (NASICON)-structured Na3V2(PO4)2F3 (NVPF) is a promising cathode for application in sodium-ion batteries (SIBs) because of its high working potential (3.7 V and 4.2 V vs. Na/Na+) and structural stability. Nonetheless, interfacial instability deteriorates its electrochemical performance. Therefore, to overcome this limitation, we introduced a sodium polyacrylate (NaPAA) binder for NVPF cathodes. The NaPAA binder effectively suppresses electrolyte decomposition by uniformly covering NVPF particles. Furthermore, the sodium carboxylate group of R–COONa in the NaPAA binder can react with the HPO2F2 intermediate generated by the hydrolysis of NaPF6 and be converted into R–COOH and NaPO2F2via the displacement of Na+ by H+. This results in the formation of a stable and Na-ion conductive NaPO2F2-rich cathode–electrolyte interphase (CEI) layer. In addition, the NaPAA-based electrode exhibits desirable cycling and rate performances compared to those of conventional poly(vinylidene difluoride)-based electrodes. This study provides new insights into the design of CEI layers by introducing chemical functional groups in the binder for high-performance SIB cathodes. [ABSTRACT FROM AUTHOR]

The increasing demand for electric vehicles, portable electronic devices, and energy storage devices has spurred interest in the development of high-capacity rechargeable lithium-ion batteries (LIBs). Polyionic liquids are used in LIB binders or electrolytes owing to their favorable physical properties. Chemical cross-linking of polymer binders has been proposed as an effective and simple method for increasing the volume of electrodes. The designed polymer binder offers high ion conductivity and robustness via an appropriate adjustment of the solid electrolyte interphase layer and chemical cross-linking during the electrochemical test. A cross-linked poly(N-allyl-vinyl imidazolium) (C-PAVIm)-based electrode can improve the cycle properties by decreasing the overpotential and allowing Li+ to flow at the interface between the active material and electrolyte. The surface of a C-PAVIm-based electrode is monitored via scanning electron microscopy and X-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy results show that the C-PAVIm-based electrode after cycling exhibits a thinner solid electrolyte interphase layer and a lower diffusion resistance as compared with a poly(vinylidene fluoride) (PVDF)-based electrode. Therefore, the C-PAVIm-based electrode exhibits better charge-discharge stability than the PVDF-based electrode. These findings imply that polymer binders with appropriately designed chemical structures can improve the electrochemical performance of LIB systems. [ABSTRACT FROM AUTHOR]