Abstract
Noble metal electrocatalysts (e.g., Pt, Ru, etc.) suffer from sluggish kinetics of water dissociation for the electrochemical reduction of water to molecular hydrogen in alkaline and neutral ...pH environments. Herein, we found that an integration of Ru nanoparticles (NPs) on oxygen-deficient WO
3-x
manifested a 24.0-fold increase in hydrogen evolution reaction (HER) activity compared with commercial Ru/C electrocatalyst in neutral electrolyte. Oxygen-deficient WO
3-x
is shown to possess large capacity for storing protons, which could be transferred to the Ru NPs under cathodic potential. This significantly increases the hydrogen coverage on the surface of Ru NPs in HER and thus changes the rate-determining step of HER on Ru from water dissociation to hydrogen recombination.
Low availability of nitrogen (N) is often a major limiting factor to crop yield in most nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most land plants that ...enhance plant nutrient uptake, particularly of phosphate. A growing number of reports point to the substantially increased N accumulation in many mycorrhizal plants; however, the contribution of AM symbiosis to plant N nutrition and the mechanisms underlying the AM-mediated N acquisition are still in the early stages of being understood. Here, we report that inoculation with AM fungus Rhizophagus irregularis remarkably promoted rice (Oryza sativa) growth and N acquisition, and about 42% of the overall N acquired by rice roots could be delivered via the symbiotic route under N-NO₃⁻ supply condition. Mycorrhizal colonization strongly induced expression of the putative nitrate transporter gene OsNPF4.5 in rice roots, and its orthologs ZmNPF4.5 in Zea mays and SbNPF4.5 in Sorghum bicolor. OsNPF4.5 is exclusively expressed in the cells containing arbuscules and displayed a low-affinity NO₃⁻ transport activity when expressed in Xenopus laevis oocytes. Moreover, knockout of OsNPF4.5 resulted in a 45% decrease in symbiotic N uptake and a significant reduction in arbuscule incidence when NO₃⁻ was supplied as an N source. Based on our results, we propose that the NPF4.5 plays a key role in mycorrhizal NO₃⁻ acquisition, a symbiotic N uptake route that might be highly conserved in gramineous species.
γ-Aminobutyric acid (GABA) is the major inhibitory transmitter in the mature brain but is excitatory in the developing cortex. We found that mouse zona incerta (ZI) projection neurons form a ...GABAergic axon plexus in neonatal cortical layer 1, making synapses with neurons in both deep and superficial layers. A similar depolarizing GABAergic plexus exists in the developing human cortex. Selectively silencing mouse ZI GABAergic neurons at birth decreased synaptic activity and apical dendritic complexity of cortical neurons. The ZI GABAergic projection becomes inhibitory with maturation and can block epileptiform activity in the adult brain. These data reveal an early-developing GABAergic projection from the ZI to cortical layer 1 that is essential for proper development of cortical neurons and balances excitation with inhibition in the adult cortex.
Lithium (Li) metal has been considered as the most promising anode material for high-energy-density batteries. However, its practical application has been affected by the growth of dendrites and ...volume change, which results in low coulombic efficiency (CE) and safety concerns during repeated Li plating/stripping. Herein, we show that a 3D current collector with graphene anchored on copper foam (GN@Cu foam) can induce uniform and stable Li deposition over a wide current density range and long-term cycling. It can maintain a CE of 97.4% for 150 cycles at a current density of 2 mA cm −2 in half cells and afford an areal capacity of 6 mA h cm −2 at 6 mA cm −2 in symmetric cells. When cycling at 0.5 mA cm −2 , the current collector presents a CE as high as 98.6% for 250 cycles in half cells and a low voltage hysteresis of 10 mV over 2000 h in symmetric cells. The GN@Cu foam serves as a conductive skeleton with moderate specific surface area and lithiophilic sites to store Li, exhibiting a dendrite-free morphology after long term cycling. This study provides novel insights into modifying a 3D current collector with lithiophilic materials towards an advanced and stable Li metal anode.
•The PdNi/CNF catalyst was synthesized by facile electrospinning and carbonization processes.•The PdNi/CNF mats were directly employed as highly efficient bifunctional catalysts for the HER and ...OER.•The hybrid materials exhibited high catalytic activity and long-term stability during the HER and OER.•We offer an effective and feasible method for generating hydrogen by water electrolysis.
Efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be developed to realize an inexpensive water-splitting system for large-scale applications. Herein, a novel PdNi carbon nanofiber (PdNi/CNF) catalyst was synthesized by facile electrospinning and carbonization processes. The size and homogeneity of the Pd−Ni alloy nanoparticles (NPs) could be effectively tuned by controlling the molar feed ratio of metal precursors .The morphology and structure of the PdNi/CNFs were characterized, and the working electrodes fabricated from the prepared catalyst mats were directly employed in the HER and OER. The PdNi/CNFs-1:2 catalyst exhibits high catalytic activity in the HER with a low overpotential of 55mV at a current density of 10mAcm−2 in an acidic solution. Moreover, under 1M KOH electrolyte, an overpotential of 187mV is required in the HER over the catalyst to arrive 10mAcm−2 and an overpotential of 289mV is achieved in the OER at the same current density. The superior HER and OER activities of the PdNi/CNFs are attributed to the synergistic effects of the PdNi alloy nanoparticles (NPs) assembled on the CNFs. This work provides a simple route for synthesizing highly efficient bifunctional electrocatalysts from 3d transition metals and a small amount of noble metals for hydrogen and oxygen evolution reactions.
The search for non-noble metal catalysts with high activity for the hydrogen evolution reaction (HER) is crucial for efficient hydrogen production at low cost and on a large scale. Herein, we report ...a novel WO3–x catalyst synthesized on carbon nanofiber mats (CFMs) by electrospinning and followed by a carbonization process in a tubal furnace. The morphology and composition of the catalysts were tailored via a simple method, and the hybrid catalyst mats were used directly as cathodes to investigate their HER performance. Notably, the as-prepared catalysts exhibit substantially enhanced activity for the HER, demonstrating a small overpotential, a high exchange current density, and a large cathodic current density. The remarkable electrocatalytic performances result from the poor crystallinity of WO3–x , the high electrical conductivity of WO3–x , and the use of electrospun CNFs. The present work outlines a straightforward approach for the synthesis of transition metal oxide (TMO)-based carbon nanofiber mats with promising applications for the HER.
Radial glia, the neural stem cells of the neocortex, are located in two niches: the ventricular zone and outer subventricular zone. Although outer subventricular zone radial glia may generate the ...majority of human cortical neurons, their molecular features remain elusive. By analyzing gene expression across single cells, we find that outer radial glia preferentially express genes related to extracellular matrix formation, migration, and stemness, including TNC, PTPRZ1, FAM107A, HOPX, and LIFR. Using dynamic imaging, immunostaining, and clonal analysis, we relate these molecular features to distinctive behaviors of outer radial glia, demonstrate the necessity of STAT3 signaling for their cell cycle progression, and establish their extensive proliferative potential. These results suggest that outer radial glia directly support the subventricular niche through local production of growth factors, potentiation of growth factor signals by extracellular matrix proteins, and activation of self-renewal pathways, thereby enabling the developmental and evolutionary expansion of the human neocortex.
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•oRG and vRG cells represent molecularly distinct subpopulations of human radial glia•oRG transcriptional state first emerges in VZ during early cortical development•Single oRG cells generate hundreds of daughter cells of diverse types•Molecular profile suggests that oRG cells sustain proliferative niche in primate OSVZ
Single-cell transcriptomics reveals molecular distinctions between human radial glia residing in the ventricular and outer subventricular zones, suggesting that outer radial glia may generate a self-sustaining proliferative niche that supports primate brain expansion during development of the cerebral cortex.
Directed differentiation from human pluripotent stem cells (hPSCs) has seen significant progress in recent years. However, most differentiated populations exhibit immature properties of an early ...embryonic stage, raising concerns about their ability to model and treat disease. Here, we report the directed differentiation of hPSCs into medial ganglionic eminence (MGE)-like progenitors and their maturation into forebrain type interneurons. We find that early-stage progenitors progress via a radial glial-like stem cell enriched in the human fetal brain. Both in vitro and posttransplantation into the rodent cortex, the MGE-like cells develop into GABAergic interneuron subtypes with mature physiological properties along a prolonged intrinsic timeline of up to 7 months, mimicking endogenous human neural development. MGE-derived cortical interneuron deficiencies are implicated in a broad range of neurodevelopmental and degenerative disorders, highlighting the importance of these results for modeling human neural development and disease.
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•hPSC-derived MGE-like GABAergic interneurons model human neural development•MGE-like progenitors display human-enriched radial glial stem cell complexity•MGE-like cells exhibit protracted maturation into functional interneuron subtypes•MGE-like cells mature and functionally integrate postinjection in the mouse brain
Directed differentiation of hPSC-derived GABAergic interneurons progress along a prolonged intrinsic timeline that mirrors stages of human postnatal development.
Abstract
Phototherapy of deep tumors still suffers from many obstacles, such as limited near-infrared (NIR) tissue penetration depth and low accumulation efficiency within the target sites. Herein, ...stimuli-sensitive tumor-targeted photodynamic nanoparticles (STPNs) with persistent luminescence for the treatment of deep tumors are reported. Purpurin 18 (Pu18), a porphyrin derivative, is utilized as a photosensitizer to produce persistent luminescence in STPNs, while lanthanide-doped upconversion nanoparticles (UCNPs) exhibit bioimaging properties and possess high photostability that can enhance photosensitizer efficacy. STPNs are initially stimulated by NIR irradiation before intravenous administration and accumulate at the tumor site to enter the cells through the HER2 receptor. Due to Pu18 afterglow luminescence properties, STPNs can continuously generate ROS to inhibit NFκB nuclear translocation, leading to tumor cell apoptosis. Moreover, STPNs can be used for diagnostic purposes through MRI and intraoperative NIR navigation. STPNs exceptional antitumor properties combined the advantages of UCNPs and persistent luminescence, representing a promising phototherapeutic strategy for deep tumors.
The absence of some forms of non-verbal communication in virtual reality (VR) can make VR-based group discussions difficult even when a leader is assigned to each group to facilitate discussions. In ...this paper, we discuss if the sensor data from off-the-shelf VR devices can be used to detect opportunities for facilitating engaging discussions and support leaders in VR-based group discussions. To this end, we focus on the detection of suppressed speaking intention in VR-based group discussions by using personalized and general models. Our extensive analysis of experimental data reveals some factors that should be considered to enable effective feedback to leaders. In particular, our results show the benefits of combining the sensor data from leaders and low-engagement participants, and the usefulness of specific HMD sensor features.
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