Dual-Size Silicon Nanocrystal-Embedded SiO_<i>x</i> Nanocomposite as a High-Capacity Lithium Storage Material

SiO_<i>x</i>-based materials attracted a great deal of attention as high-capacity Li⁺ storage materials for lithium-ion batteries due to their high reversible capacity and good cycle performance. However, these materials still suffer from low initial Coulombic efficiency as well as high production cost, which are associated with the complicated synthesis process. Here, we propose a dual-size Si nanocrystal-embedded SiO_<i>x</i> nanocomposite as a high-capacity Li⁺ storage material prepared <i>via</i> cost-effective sol–gel reaction of triethoxysilane with commercially available Si nanoparticles. In the proposed nanocomposite, dual-size Si nanocrystals are incorporated into the amorphous SiO_<i>x</i> matrix, providing a high capacity (1914 mAh g^–1) with a notably improved initial efficiency (73.6%) and stable cycle performance over 100 cycles. The highly robust electrochemical and mechanical properties of the dual-size Si nanocrystal-embedded SiO_<i>x</i> nanocomposite presented here are mainly attributed to its peculiar nanoarchitecture. This study represents one of the most promising routes for advancing SiO_<i>x</i>-based Li⁺ storage materials for practical use

Dendrite-Free Polygonal Sodium Deposition with Excellent Interfacial Stability in a NaAlCl₄–2SO₂ Inorganic Electrolyte

Room-temperature Na-metal-based rechargeable batteries, including Na–O₂ and Na–S systems, have attracted attention due to their high energy density and the abundance of sodium resources. Although these systems show considerable promise, concerns regarding the use of Na metal should be addressed for their success. Here, we report dendrite-free Na-metal electrode for a Na rechargeable battery, engineered by employing nonflammable and highly Na⁺-conductive NaAlCl₄·2SO₂ inorganic electrolyte, as a result, showing superior electrochemical performances to those in conventional organic electrolytes. We have achieved a hard-to-acquire combination of nondendritic Na electrodeposition and highly stable solid electrolyte interphase at the Na-metal electrode, enabled by inducing polygonal growth of Na deposit using a highly concentrated Na⁺-conducting inorganic electrolyte and also creating highly dense passivation film mainly composed of NaCl on the surface of Na-metal electrode. These results are highly encouraging in the development of room-temperature Na rechargeable battery and provide another strategy for highly reliable Na-metal-based rechargeable batteries

Surface distribution of iGluR complexes at various Neto levels.

<p>(A) Confocal images of NMJ4 in third instar larvae of indicated genotypes labeled for GluRIIC (green), and HRP (red). Surface distribution of GluRIIC at synaptic and extrasynaptic locations was captured by immunohistochemistry with an N-terminal-specific antibody in detergent-free conditions. The GluRIIC signals were absent in the knockdown control (<i>G14>GluRIIC^RNAi</i>) and were shifted from synaptic to extrasynaptic locations at either low (<i>G14>neto^RNAi</i>) and excess Neto levels (<i>neto³⁶;G14>neto-A3</i> and <i>G14>neto-A1</i>) (quantified in B). The image insets are shown at higher intensity. The numbers of NMJs examined are indicated in each bar. Error bars indicate SEM. *; <i>p</i><0.001, **; p<0.01. Bars: 10 μm, 1 μm in details.</p

Ultrasound-Driven Triboelectric Nanogenerator with Biocompatible 2‑Hydroxyethyl Methacrylate

Ultrasound-driven triboelectric nanogenerators (TENGs) were recently proposed as an energy solution technology for a sustainable lifespan of implantable medical devices (IMDs). While the improvement of ultrasound transmission is crucial for achieving high energy generation, research on the material properties of ultrasound-driven TENGs is still in its initial stage. In this work, multifunctional, biocompatible 2-hydroxyethyl methacrylate (HEMA) is suggested as both an encapsulation and triboelectric layer for an implantable, modulus-tunable ultrasound-driven TENG (IMU-TENG). By adjusting the acoustic impedance of HEMA to be suitable for the surrounding environment, the ultrasonic transmission coefficient is about 10 times higher than that of a titanium (Ti) plate. Under in vivo conditions, the IMU-TENG generates sufficient energy to charge a 100 μF capacitor 3.7 times faster than the case with a Ti plate. This strategy of using multifunctional HEMA for high-performance ultrasound-driven TENGs could be a promising energy solution for low-powered IMDs

Prodomain Removal Enables Neto to Stabilize Glutamate Receptors at the <i>Drosophila</i> Neuromuscular Junction

<div><p>Stabilization of neurotransmitter receptors at postsynaptic specializations is a key step in the assembly of functional synapses. <i>Drosophila</i> Neto (Neuropillin and Tolloid-like protein) is an essential auxiliary subunit of ionotropic glutamate receptor (iGluR) complexes required for the iGluRs clustering at the neuromuscular junction (NMJ). Here we show that optimal levels of Neto are crucial for stabilization of iGluRs at synaptic sites and proper NMJ development. Genetic manipulations of Neto levels shifted iGluRs distribution to extrajunctional locations. Perturbations in Neto levels also produced small NMJs with reduced synaptic transmission, but only Neto-depleted NMJs showed diminished postsynaptic components. <i>Drosophila</i> Neto contains an inhibitory prodomain that is processed by Furin1-mediated limited proteolysis. <i>neto</i> null mutants rescued with a Neto variant that cannot be processed have severely impaired NMJs and reduced iGluRs synaptic clusters. Unprocessed Neto retains the ability to engage iGluRs in vivo and to form complexes with normal synaptic transmission. However, Neto prodomain must be removed to enable iGluRs synaptic stabilization and proper postsynaptic differentiation.</p></div

The prodomain restricts Neto activities.

<p>(A) Diagram and Western blot analysis of constitutively active (CA) and processing mutant (PM) Neto-GFP variants. (B) Fluorescence images of salivary glands from third instar larvae expressing Neto-GFP variants as indicated (<i>G14>neto-GFP</i>). Prodomain processing did not affect the apical localization of Neto. (C) Co-immunoprecipitation (IP: α-GFP, WB: α-GluRIIC) from muscle extracts from control (<i>y¹w¹¹¹⁸</i>) and <i>neto</i> rescued larvae (<i>neto³⁶;G14>CA-neto-GFP</i> and <i>neto³⁶;G14>PM-neto-GFP</i>) showed that both CA- and PM-Neto bind iGluRs. (D-E) PM-Neto is less efficient in rescuing the embryonic lethality and adult viability of <i>neto</i> null mutants compared with control or CA-Neto. Genotypes: control (<i>neto³⁶;G14>neto-GFP</i> at 25°C); CA-Neto normal (<i>neto³⁶;G14>CA-neto-GFP-N4</i> at 18°C); CA-Neto high (<i>neto³⁶;G14>CA-neto-GFP-N4</i> at 25°C); PM-Neto normal (<i>neto³⁶;G14>PM-neto-GFP-D2</i> at 25°C); PM-Neto high (<i>neto³⁶;G14>PM-neto-GFP-D1</i> at 25°C). The numbers of animals analyzed are indicated in each bar. Bars: 10 μm.</p

High Neto levels affect the BMP signaling.

<p>(A) Confocal images of NMJ4 (segment A4) in larvae of indicated genotypes labeled for GluRIIA (green), pMad (red), and HRP (blue). Excess Neto induced a decrease in the intensity but not number of synaptic GluRIIA and pMad signals (quantified in B-C). All samples were processed and imaged similarly using at least ten NMJs per genotype. Error bars indicate SEM. *; <i>p</i><0.001, **; <i>p</i><0.01, ***; <i>p</i><0.05. Bars: 10 μm.</p

Prodomain processing affects Neto-mediated iGluR clustering.

<p>(A-B) Confocal images of NMJ4 (A) and bouton details (B) in larvae of indicated genotypes labeled for Brp (green), GluRIIC (red), and Neto (blue). Similar to <i>neto</i> transgenes, <i>CA-neto</i> induced dose-dependent gain-of-function NMJ phenotypes. In contrast, <i>PM-neto</i> transgenes severely disrupted the NMJ morphology and the synaptic contacts. (C) Confocal images of NMJ4 labeled for GluRIIA (green), GluRIIB (red), and HRP (blue) uncovered a drastic reduction of GluRIIA synaptic signals at PM-Neto rescued NMJs. (D) Western blot comparison of Neto expression levels in muscle extracts from third instar larvae rescued with: (i) untagged Neto (lane 2, <i>neto³⁶;G14>neto-A3</i>); (ii) CA-Neto-GFP, normal (lane 3) and high (lane 4); and (iii) PM-Neto-GFP, normal (lane 5) and high (lane 6). (*) uncleaved proteins. (E-F) Quantification of various synaptic signals at <i>neto</i> null NMJs rescued with normal levels of CA- and PM-Neto. (G) Bouton numbers were severely reduced at PM-Neto rescued NMJs. The numbers of NMJs examined are indicated in each bar. Genotypes: CA-Neto normal (<i>neto³⁶;G14>CA-neto-GFP-N4</i> at 18°C); CA-Neto high (<i>neto³⁶;G14>CA-neto-GFP-N4</i> at 25°C); PM-Neto normal (<i>neto³⁶;G14>PM-neto-GFP-D2</i> at 25°C); PM-Neto high (<i>neto³⁶;G14>PM-neto-GFP-D1</i> at 25°C). Error bars indicate SEM. *; <i>p</i><0.001, **; <i>p</i><0.01. Bars: 10 μm, 1 μm in details.</p

Neto contains a prodomain cleaved by Furin1-mediated limited proteolysis.

<p>(A-B) Diagrams and Western blot analyses of various Neto constructs. (A) Neto-V5/His is full-length Neto (SP- signal peptide, CUB1 and -2- the CUB domains, L- LDLa motif, TM- transmembrane domain) C-tagged with V5-6xHis epitopes (V5). Neto-extra-V5 contains only the extracellular part. The majority of tagged Netos were detected as cleaved forms in tissue culture or rescued embryos (<i>neto³⁶;da>neto-V5</i>). (*) uncleaved proteins. (B) A short variant including the CUB1 domain retained processing; the C-end fragment was used to identify the cleavage site(s). (C) <i>Drosophila</i> Neto proteins contain highly conserved Furin consensus sites (arrows). The R-Q bond, 9 residues upstream the CUB1 domain (in blue) appears to be the primary cleavage site. (D-E) RNAi interference in S2 cells showed that Fur1 cleaves Neto. The efficiency of RNAi treatment was verified by RT-PCR and DNA analyses relative to β-Actin control (D). Fur2 did not influence Neto processing. In S2 cells, Amon expression levels were too low to rule out its contribution. The data shown are representative images from five experimental repeats.</p