Dual‐sites single atom catalysts hold promise for efficiently regulating multiple reaction processes and explicitly explaining the underlying mechanisms. However, delicate atomic engineering for ...dual‐site single atom catalysts remains a huge challenge. Herein, atomically dispersed Fe‐Ni single atoms embedded in a nitrogen‐doped carbon matrix (FeNi SAs/NC) are successfully developed with extraordinary activity for electrocatalytic oxygen reduction and evolution reactions (ORR/OER). The atomic FeNi SAs/NC catalyst displays high onset potential (0.98 V) and half‐wave potential (0.84 V) for the ORR, as well as, low overpotential of (270 mV) at 10 mA cm−2 for the OER. The density functional theory calculations indicate that the Fe site as the active center can facilitate the four‐electron reaction process, while Ni sites regulate the electronic structure of Fe sites and further reduce the energy barrier of the rate‐determining step. In addition, the nitrogen‐doped carbon matrix prevents the metal atoms from aggregation and corrosion, leading to the improvement of catalyst durability. As a proof of concept, flexible quasi‐solid‐state zinc– and aluminum–air batteries assembled with the FeNi SAs/NC catalyst exhibit superior peak power densities and discharging specific capacities outperforming the commercial Pt/C. This work provides rational guidance for the synthesis of bifunctional electrocatalysts in next‐generation energy devices for flexible consumer electronics.
Unique noble metal‐free electrocatalysts with atomically dispersed Fe‐Ni dual‐sites are precisely designed and present superior oxygen reduction and evolution reaction reactivity under alkaline conditions, which provides a perspective and guidance for the design of efficient catalysts for metal–air batteries.
Astrocytes are the most abundant cell type in the brain, where they perform a wide array of functions, yet the nature of their cellular heterogeneity and how it oversees these diverse roles remains ...shrouded in mystery. Using an intersectional fluorescence-activated cell sorting-based strategy, we identified five distinct astrocyte subpopulations present across three brain regions that show extensive molecular diversity. Application of this molecular insight toward function revealed that these populations differentially support synaptogenesis between neurons. We identified correlative populations in mouse and human glioma and found that the emergence of specific subpopulations during tumor progression corresponded with the onset of seizures and tumor invasion. In sum, we have identified subpopulations of astrocytes in the adult brain and their correlates in glioma that are endowed with diverse cellular, molecular and functional properties. These populations selectively contribute to synaptogenesis and tumor pathophysiology, providing a blueprint for understanding diverse astrocyte contributions to neurological disease.
Astrocytes play essential roles in brain function by supporting synaptic connectivity and associated circuits. How these roles are regulated by transcription factors is unknown. Moreover, there is ...emerging evidence that astrocytes exhibit regional heterogeneity, and the mechanisms controlling this diversity remain nascent. Here, we show that conditional deletion of the transcription factor nuclear factor I-A (NFIA) in astrocytes in the adult brain results in region-specific alterations in morphology and physiology that are mediated by selective DNA binding. Disruptions in astrocyte function following loss of NFIA are most pronounced in the hippocampus, manifested by impaired interactions with neurons, coupled with diminution of learning and memory behaviors. These changes in hippocampal astrocytes did not affect basal neuronal properties but specifically inhibited synaptic plasticity, which is regulated by NFIA in astrocytes through calcium-dependent mechanisms. Together, our studies reveal region-specific transcriptional dependencies for astrocytes and identify astrocytic NFIA as a key transcriptional regulator of hippocampal circuits.
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•NFIA is required to maintain astrocyte function in a brain-region-specific manner•Brain-region-specific DNA binding by NFIA is inhibited by its association with NFIB•Astrocyte-neuron communication in the hippocampus is disrupted•Synaptic plasticity and memory are impaired in mice lacking astrocytic NFIA
Astrocytes play essential roles in brain function by supporting synaptic connectivity and associated circuits. We found the transcription factor NFIA is required to maintain astrocyte function in the hippocampus through region-specific DNA binding mechanisms. Alterations in astrocyte-neuron communication disrupt hippocampal circuit function, resulting in impaired learning and memory behaviors.
Spintronic elements based on spin transfer torque have emerged with potential for on‐chip memory, but they suffer from large energy dissipation due to the large current densities required. In ...contrast, an electric‐field‐driven magneto‐electric storage element can operate with capacitive displacement charge and potentially reach 1–10 µJ cm−2 switching operation. Here, magneto‐electric switching of a magnetoresistive element is shown, operating at or below 200 mV, with a pathway to get down to 100 mV. A combination of phase detuning is utilized via isovalent La substitution and thickness scaling in multiferroic BiFeO3 to scale the switching energy density to ≈10 µJ cm−2. This work provides a template to achieve attojoule‐class nonvolatile memories.
Spintronic elements based on spin transfer torque have emerged with potential for on‐chip memory, but they suffer from large energy dissipation. Magneto‐electric switching of a magnetoresistive element operating at or below 200 mV with a pathway to reduce a switching energy density to ≈10 µJ cm‐2 is shown. This work provides a template to achieve attojoule‐class nonvolatile memories.
Two compact, printed, ultrawideband (UWB) monopole antennas with tri-band notched characteristics are reported. The notched filters are achieved by introducing printed, electrically small, ...capacitively-loaded loop (CLL) resonators. The directly driven elements consist of printed top-loaded CLL-based monopoles and 50 Ω microstrip feed lines. By adding three CLL elements close to the feed line, band-notch properties in the WiMAX (3.3-3.6GHz), lower WLAN (5.15-5.35GHz) and higher WLAN (5.725-5.825GHz) bands are achieved. Each antenna system is contained on a 27×34mm 2 sheet of Rogers Duroid 5880 substrate. One is designed with three additional CLL elements; the other is achieved with only two. Comparisons between the simulation and measurement results show that these UWB antennas have broadband matched impedance values and stable radiation patterns for all radiating frequencies.
Abstract
Magnetoelectric coupling at room temperature in multiferroic materials, such as BiFeO
3
, is one of the leading candidates to develop low-power spintronics and emerging memory technologies. ...Although extensive research activity has been devoted recently to exploring the physical properties, especially focusing on ferroelectricity and antiferromagnetism in chemically modified BiFeO
3
, a concrete understanding of the magnetoelectric coupling is yet to be fulfilled. We have discovered that La substitutions at the Bi-site lead to a progressive increase in the degeneracy of the potential energy landscape of the BiFeO
3
system exemplified by a rotation of the polar axis away from the 〈111〉
pc
towards the 〈112〉
pc
discretion. This is accompanied by corresponding rotation of the antiferromagnetic axis as well, thus maintaining the right-handed vectorial relationship between ferroelectric polarization, antiferromagnetic vector and the Dzyaloshinskii-Moriya vector. As a consequence, La-BiFeO
3
films exhibit a magnetoelectric coupling that is distinctly different from the undoped BiFeO
3
films.
Long-range transport (LRT) of air pollutants from East Asia during the northeast monsoon season impacts several downwind locations. In 2020, the initial COVID-19 lockdowns in China overlapped with ...Week 3 of the Chinese New Year (CNY) holiday, and an Asian outflow event. Thus, movement of the Chinese populace from city to city was already greatly reduced by the time of the LRT episode, although the reductions in industrial output are less clear. We found NO2 column concentrations were reduced by 24% during the CNY Week 3 this year compared to previous years. The attenuated transport event arrived to northern Taiwan with a PM2.5 concentration <45 μg m−3 and most often <35 μg m−3, which is 2–3 times lower than LRT episodes of similar back-trajectory and synoptic patterns. The whole episode persisted for about 60 h, longer than most LRT episodes from China to Taiwan. CMAQ v5.2.1 modeling of the LRT event with 100% emission and reduced emission scenarios, revealed emissions in China were approximately 50% less than normal periods. Due to the length of the episode and the significant reduction in emissions, Taiwan avoided a PM2.5 surplus of 19.2 μg m−3 on average during the episode, equivalent to a 0.5 μg m−3 reduction for the whole 3-month winter season. Employing the 100% emission model scenario and scaling up to the average episode hours each winter, the PM2.5 surplus delivered via plumes on the northeast monsoon is equivalent to a 0.5 μg m−3 surplus for the whole year.
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•COVID-19 lockdown in China reduced long-range transport of air pollution to Taiwan.•OMI NO2 over central-north China reduced by 24% compared to previous years.•PM2.5 concentration in northern Taiwan 2 times lower compared to similar episode•CMAQ simulation with 50% reduced emission in China matches measured PM2.5 in Taiwan.•Avoided PM2.5 pollution equivalent to 0.5 μg m−3 reduction for entire winter season
Abstract
Architected materials that actively respond to external stimuli hold tantalizing prospects for applications in energy storage, wearable electronics, and bioengineering. Molybdenum disulfide, ...an excellent two-dimensional building block, is a promising candidate for lithium-ion battery anode. However, the stacked and brittle two-dimensional layered structure limits its rate capability and electrochemical stability. Here we report the dewetting-induced manufacturing of two-dimensional molybdenum disulfide nanosheets into a three-dimensional foam with a structural hierarchy across seven orders of magnitude. Our molybdenum disulfide foam provides an interpenetrating network for efficient charge transport, rapid ion diffusion, and mechanically resilient and chemically stable support for electrochemical reactions. These features induce a pseudocapacitive energy storage mechanism involving molybdenum redox reactions, confirmed by in-situ X-ray absorption near edge structure. The extraordinary electrochemical performance of molybdenum disulfide foam outperforms most reported molybdenum disulfide-based Lithium-ion battery anodes and state-of-the-art materials. This work opens promising inroads for various applications where special properties arise from hierarchical architecture.
Oxide interfaces exhibit a broad range of physical effects stemming from broken inversion symmetry. In particular, they can display non‐reciprocal phenomena when time reversal symmetry is also ...broken, e.g., by the application of a magnetic field. Examples include the direct and inverse Edelstein effects (DEE, IEE) that allow the interconversion between spin currents and charge currents. The DEE and IEE have been investigated in interfaces based on the perovskite SrTiO3 (STO), albeit in separate studies focusing on one or the other. The demonstration of these effects remains mostly elusive in other oxide interface systems despite their blossoming in the last decade. Here, the observation of both the DEE and IEE in a new interfacial two‐dimensional electron gas (2DEG) based on the perovskite oxide KTaO3 is reported. 2DEGs are generated by the simple deposition of Al metal onto KTaO3 single crystals, characterized by angle‐resolved photoemission spectroscopy and magnetotransport, and shown to display the DEE through unidirectional magnetoresistance and the IEE by spin‐pumping experiments. Their spin–charge interconversion efficiency is then compared with that of STO‐based interfaces, related to the 2DEG electronic structure, and perspectives are given for the implementation of KTaO3 2DEGs into spin–orbitronic devices is compared.
2D electron gases formed by sputtering a thin film of Al onto KTaO3 crystals are used to interconvert charge and spin currents with a high efficiency, thanks to the large Rashba spin–orbit coupling in the electron gas. These results are relevant for the integration of quantum oxide materials into spintronics devices.
ENO1 (α-enolase) expression is significantly correlated with reduced survival and poor prognosis in many cancer types, including lung cancer. However, the function of ENO1 in carcinogenesis remains ...elusive. In this study, we found that high expression of ENO1 is present in metastatic lung cancer cell lines and malignant tumors and is associated with poor overall survival of patients with lung cancer. Knockdown of ENO1 decreased cancer cell proliferation and invasiveness, whereas overexpression of ENO1 enhanced these processes. Moreover, ENO1 expression promoted tumor growth in orthotopic models and enhanced lung tumor metastasis in tail-vein injection models. These effects were mediated by upregulation of mesenchymal markers N-cadherin and vimentin and the epithelial-to-mesenchymal transition regulator SLUG, along with concurrent downregulation of E-cadherin. Mechanistically, ENO1 interacted with hepatocyte growth factor receptor (HGFR) and activated HGFR and Wnt signaling via increased phosphorylation of HGFR and the Wnt coreceptor LRP5/6. Activation of these signaling axes decreased GSK3β activity via Src-PI3K-AKT signaling and inactivation of the β-catenin destruction complex to ultimately upregulate SLUG and β-catenin. In addition, we generated a chimeric anti-ENO1 mAb (chENO1-22) that can decrease cancer cell proliferation and invasion. chENO1-22 attenuated cancer cell invasion by inhibiting ENO1-mediated GSK3β inactivation to promote SLUG protein ubiquitination and degradation. Moreover, chENO1-22 prevented lung tumor metastasis and prolonged survival in animal models. Taken together, these findings illuminate the molecular mechanisms underlying the function of ENO1 in lung cancer metastasis and support the therapeutic potential of a novel antibody targeting ENO1 for treating lung cancer. SIGNIFICANCE: This study shows that ENO1 promotes lung cancer metastasis via HGFR and WNT signaling and introduces a novel anti-ENO1 antibody for potential therapeutic use in lung cancer.
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