Excavating and developing highly efficient and cost‐effective nonnoble metal single‐atom catalysts for electrocatalytic reactions is of paramount significance but still in its infancy. Herein, reported is a general NaCl template‐assisted strategy for rationally designing and preparing a series of isolated transition metal single atoms (Fe/Co/Ni) anchored on honeycomb‐like nitrogen‐doped carbon matrix (M1‐HNC‐T1‐T2, M = Fe/Co/Ni, T1 = 500 °C, T2 = 850 °C). The resulting M1‐HNC‐500‐850 with M‐N4 active sites exhibits superior capability for oxygen reduction reaction (ORR) with the half‐wave potential order of Fe1‐HNC‐500‐850 > Co1‐HNC‐500‐850 > Ni1‐HNC‐500‐850, in which Fe1‐HNC‐500‐850 shows better performance than commercial Pt/C. Density functional theory calculations reveal a choice strategy that the strong p–d‐coupled spatial charge separation results the Fe‐N4 effectively merges active electrons for elevating d‐band activity in a van‐Hove singularity like character. This essentially generalizes an optimal electronic exchange‐and‐transfer (ExT) capability for boosting sluggish alkaline ORR activity. This work not only presents a universal strategy for preparing single‐atom electrocatalyst to accelerate the kinetics of cathodic ORR but also provides an insight into the relationship between the electronic structure and the electrocatalytical activity.

In the CNS, myelination and remyelination depend on the successful progression and maturation of oligodendroglial lineage cells, including proliferation and differentiation of oligodendroglial progenitor cells (OPCs). Previous studies have reported that Sox2 transiently regulates oligodendrocyte (OL) differentiation in the embryonic and perinatal spinal cord and appears dispensable for myelination in the postnatal spinal cord. However, the role of Sox2 in OL development in the brain has yet to be defined. We now report that Sox2 is an essential positive regulator of developmental myelination in the postnatal murine brain of both sexes. Stage-specific paradigms of genetic disruption demonstrated that Sox2 regulated brain myelination by coordinating upstream OPC population supply and downstream OL differentiation. Transcriptomic analyses further supported a crucial role of Sox2 in brain developmental myelination. Consistently, oligodendroglial Sox2-deficient mice developed severe tremors and ataxia, typical phenotypes indicative of hypomyelination, and displayed severe impairment of motor function and prominent deficits of brain OL differentiation and myelination persisting into the later CNS developmental stages. We also found that Sox2 was required for efficient OPC proliferation and expansion and OL regeneration during remyelination in the adult brain and spinal cord. Together, our genetic evidence reveals an essential role of Sox2 in brain myelination and CNS remyelination, and suggests that manipulation of Sox2 and/or Sox2-mediated downstream pathways may be therapeutic in promoting CNS myelin repair. Promoting myelin formation and repair has translational significance in treating myelin-related neurological disorders, such as periventricular leukomalacia and multiple sclerosis in which brain developmental myelin formation and myelin repair are severely affected, respectively. In this report, analyses of a series of genetic conditional knock-out systems targeting different oligodendrocyte stages reveal a previously unappreciated role of Sox2 in coordinating upstream proliferation and downstream differentiation of oligodendroglial lineage cells in the mouse brain during developmental myelination and CNS remyelination. Our study points to the potential of manipulating Sox2 and its downstream pathways to promote oligodendrocyte regeneration and CNS myelin repair.

Designing well‐defined nanointerfaces is of prime importance to enhance the activity of nanoelectrocatalysts for different catalytic reactions. However, studies on non‐noble‐metal‐interface electrocatalysts with extremely high activity and superior stability at high current density still remains a great challenge. Herein, a class of Co3O4/Fe0.33Co0.66P interface nanowires is rationally designed for boosting oxygen evolution reaction (OER) catalysis at high current density by partial chemical etching of Co(CO3)0.5(OH)·0.11H2O (Co‐CHH) nanowires with Fe(CN)63−, followed by low‐temperature phosphorization treatment. The resulting Co3O4/Fe0.33Co0.66P interface nanowires exhibit very high OER catalytic performance with an overpotential of only 215 mV at a current density of 50 mA cm−2 and a Tafel slope of 59.8 mV dec−1 in 1.0 m KOH. In particular, Co3O4/Fe0.33Co0.66P exhibits an obvious advantage in enhancing oxygen evolution at high current density by showing an overpotential of merely 291 mV at 800 mA cm−2, much lower than that of RuO2 (446 mV). Co3O4/Fe0.33Co0.66P is remarkably stable for the OER with negligible current loss under overpotentials of 200 and 240 mV for 150 h. Theoretical calculations reveal that Co3O4/Fe0.33Co0.66P is more favorable for the OER since the electrochemical catalytic oxygen evolution barrier is optimally lowered by the active Co‐ and O‐sites from the Co3O4/Fe0.33Co0.66P interface.

The mechanisms by which oligodendroglia modulate CNS angiogenesis remain elusive. Previous in vitro data suggest that oligodendroglia regulate CNS endothelial cell proliferation and blood vessel formation through hypoxia inducible factor alpha (HIFα)-activated Wnt (but not VEGF) signaling. Using in vivo genetic models, we show that HIFα in oligodendroglia is necessary and sufficient for angiogenesis independent of CNS regions. At the molecular level, HIFα stabilization in oligodendroglia does not perturb Wnt signaling but rather activates VEGF. At the functional level, genetically blocking oligodendroglia-derived VEGF but not Wnt significantly decreases oligodendroglial HIFα-regulated CNS angiogenesis. Blocking astrogliaderived Wnt signaling reduces astroglial HIFα-regulated CNS angiogenesis. Together, our in vivo data demonstrate that oligodendroglial HIFα regulates CNS angiogenesis through Wnt-independent and VEGF-dependent signaling. These findings suggest an alternative mechanistic understanding of CNS angiogenesis by postnatal glial cells and unveil a glial cell type-dependent HIFα-Wnt axis in regulating CNS vessel formation.

In this work, the effective fluorescence quenching ability of polydopamine nanotubes (PDANTs) toward various fluorescent dyes was studied and further applied to fluorescent biosensing for the first time. The PDANTs could quench the fluorophores with different emission frequencies, aminomethylcoumarin acetate (AMCA), 6-carboxyfluorescein (FAM), 6-carboxytetramethylrhodamine (TAMRA), and Cy5. All the quenching efficiencies reached to more than 97%. Taking advantage of PDANTs' different affinities toward ssDNA and dsDNA and utilizing the complex of FAM-labeled ssDNA and PDANTs as a sensing platform, we achieved highly sensitive and selective detection of human immunodeficiency virus (HIV) DNA and adenosine triphosphate (ATP) assisted with Exonuclease III amplification. The limits of detection (LODs) of HIV DNA and ATP reached to 3.5 pM and 150 nM, respectively, which were all lower than that of previous nanoquenchers with Exo III amplification, and the platform also presented good applicability in biological samples. Fluorescent sensing applications of this nanotube enlightened other targets detection based upon it and enriched the building blocks of fluorescent sensing platforms. This polydopamine nanotube also possesses excellent biocompatibility and biodegradability, which is suitable for future drug delivery, cell imaging, and other biological applications.

It has previously been shown that environmental enrichment can enhance structural plasticity in the brain and thereby improve cognitive and behavioral function. In this study, we reared developmentally noise-exposed rats in an acoustic-enriched environment for ϳ4 weeks to investigate whether or not enrichment could restore developmentally degraded behavioral and neuronal processing of sound frequency. We found that noise-exposed rats had significantly elevated sound frequency discrimination thresholds compared with agematched naive rats. Environmental acoustic enrichment nearly restored to normal the behavioral deficit resulting from early disrupted acoustic inputs. Signs of both degraded frequency selectivity of neurons as measured by the bandwidth of frequency tuning curves and decreased long-term potentiation of field potentials recorded in the primary auditory cortex of these noise-exposed rats also were reversed partially. The observed behavioral and physiological effects induced by enrichment were accompanied by recovery of cortical expressions of certain NMDA and GABA A receptor subunits and brain-derived neurotrophic factor. These studies in a rodent model show that environmental acoustic enrichment promotes recovery from early noise-induced auditory cortical dysfunction and indicate a therapeutic potential of this noninvasive approach for normalizing neurological function from pathologies that cause hearing and associated language impairments in older children and adults.

issues which should be taken seriously. Plenty of logic devices with multi-output signals are implemented by the aid of covalently labeled reporters (e.g., dye or redox), which cause time wastage and high cost. [10][11][12][13][14][15][16][17] In order to generate more than one output signal, it is ineluctable to introduce many other types of substances (e.g., different dyes and unstable hydrogen peroxide), [18,19] which increase complexity of a logic platform and are much detrimental to the repeatability and assembly of different logic systems. In addition, sequence redesign is required for construction of different logic gates, which leads to high cost and low efficiency. Hence, to explore a simple and noncovalent logic platform in a cost-effective manner is urgently demanded.Aimed at surmounting these drawbacks, new DNA-based logic systems should be considered. DNA-templated silver nanoclusters (AgNCs) with excellent fluorescence properties have attracted wide research interests in the field of fabrication of logic devices, [20][21][22][23][24] due to remarkable merits, such as low cost, tunable emission wavelength, ease of preparation, and convenience of utilization in DNA reaction circuits, and noncovalent (so called label-free) and distinctive logic systems could be designed. [21,22,25,26] Recently, a concept of "DNA Janus Logic Pair", also named as "Contrary Logic Pair", was proposed, [18,27] in which two contrary logic gates (positive and negative gates) were obtained via the same one-time reaction, resulting in significant improvement of computing efficiency. However, systematic complexity remains as a constraining factor for effective implementation and integration of DNA-based logic systems. In this study, diverse concomitant contrary logic gates (CCLGs), such as INHIBIT (INH)^IMPLICATION (IMP), XOR^XNOR and MAJORITY (MAJ)^MINORITY (MIN) ("^" stands for "concomitant and contrary"), and extended concatenated logic circuits (e.g., 4-input MAJ||MIN-INH||IMP, "||" stands for "parallel") with specific functions (e.g., parity generator (Pg) and checker (Pc)) were constructed, by utilization of one novel type of hairpin DNA-templated AgNCs (H-AgNCs) as the universal dualfluorescence signal transducer, and based on the mechanism of DNA hybridization and toehold-mediated strand displacement (TSD). Each pair of CCLGs was achieved via the same DNA (YES^NOT, OR^NOR, INHIBIT^IMPLICATION, XOR^XNOR, and MAJORITY^MINORITY) and extended concatenated logic circuits are presented and some of them perform specific functions, such as parity generators and checkers. The introduction of H-AgNCs as noncovalent signal reporters avoids tedious and high-cost labeling procedures. Of note, the concomitant feature of CCLGs attributed to the dual-emitter AgNCs conduces to reducing the time and cost to devise multiple logic gates. As compared to previous ones, this design eliminates numerous substances (e.g., organic dyes) and unstable components (hydrogen peroxide), which not only decreases the complexity of logic performs and impr...

The global pandemic of coronavirus has caused a huge blow to the whole human society. [1] In this regard, the development of renewable energy and corresponding energy Constructing ionic conductive hydrogels with diversified properties is crucial for portable zinc-ion hybrid supercapacitors (ZHSCs). Herein, a freezetolerant hydrogel electrolyte (AF PVA-CMC/Zn(CF 3 SO 3 ) 2 ) is developed by forming a semi-interpenetrating anti-freezing polyvinyl alcohol-carboxymethyl cellulose (AF PVA-CMC) network filled with the ethylene glycol (EG)containing Zn(CF 3 SO 3 ) 2 aqueous solution. The semi-interpenetrating AF PVA-CMC/Zn(CF 3 SO 3 ) 2 possesses enhanced mechanical properties, realizes the uniform zinc deposition, and impedes the dendrite growth. Notably, the interaction between PVA and EG suppresses the ice crystal formation and prevents freezing at −20 °C. Due to these advantages, the designed hydrogel owns high ionic conductivity of 1.73/0.75 S m −1 at 20/−20 °C with excellent tensile/compression strength at 20 °C. Impressively, the flexible AF quasi-solid-state ZHSC employing the hydrogel electrolyte achieves a superior energy density at 20/−20 °C (87.9/60.7 Wh kg −1 ). It maintains nearly 84.8% of the initial capacity after 10 000 cycles and a low self-discharge rate (1.77 mV h −1 ) at 20 °C, together with great tolerance to corrosion. Moreover, this device demonstrates a stable electrochemical performance at −20 °C under deformation. The obtained results provide valuable insights for constructing durable hydrogel electrolytes in cold environments.