A high efficiency and great tunability of bandwidth and absorption‐range electromagnetic wave absorber is proposed without precedent. A series of 2D carbon‐based nanocomposites with the loading of ...cerium oxide (CN‐Ce) and other types of rare earth oxides (CN‐REOs) can be successfully synthesized by a simple solvothermal‐sintering method. As‐synthesized 2D nanocomposites with local graphite‐like C3N4 structure and trace N‐doped are identified by transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. The CN‐REOs and polyvinylidene fluoride composite absorbers with reflection loss values above −40 dB are obtained in C‐band, X‐band, and Ku‐band, respectively. The empirical rules on effective bandwidth and frequency range are discovered and summarized, which can be successfully realized by simply tuning the doping amount or type of REO. The mechanism is explained by enhanced attenuation and tunable impedance matching. In addition co‐filled samples by two types of CN‐REOs nanocomposites are prepared to support these findings and inspire the preparation of absorber with desirable frequency band in the range of 2–18 GHz.
In the system of composites of PVDF and trace n‐doped carbon nanocomposites loaded with rare earth oxide, a high‐performance electromagnetic wave‐absorbing composite with adjustable electromagnetic wave absorption frequency range and adjustable effective absorption width is obtained. Regular performance is found based on extensive experimental data and analysis of intrinsic performance. In addition, the empirical conclusions are well‐validated by co‐filled (CN‐Ce+CN‐Eu)/PVDF samples.
Exploring low‐cost and high‐performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal–air batteries is crucial for the commercialization of these ...energy conversion and storage devices. Here we report a novel NPMC consisting of Fe3C nanoparticles encapsulated in mesoporous Fe‐N‐doped carbon nanofibers, which is synthesized by a cost‐effective method using carbonaceous nanofibers, pyrrole, and FeCl3 as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of −0.02 V and half‐wave potential of −0.140 V) closely comparable to the state‐of‐the‐art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.
Nanocomposite electrocatalyst: A high‐performance electrocatalyst for the oxygen reduction reaction (ORR) is based on Fe3C nanoparticles encapsulated in mesoporous Fe‐N‐doped carbon nanofibers. It can be synthesized from low‐cost and abundant precursors and exhibits excellent electrocatalytic performance for the ORR in both alkaline and acidic media.
Activation of tumor suppressors for the treatment of human cancer has been a long sought, yet elusive, strategy. PTEN is a critical tumor suppressive phosphatase that is active in its dimer ...configuration at the plasma membrane. Polyubiquitination by the ubiquitin E3 ligase WWP1 (WW domain-containing ubiquitin E3 ligase 1) suppressed the dimerization, membrane recruitment, and function of PTEN. Either genetic ablation or pharmacological inhibition of WWP1 triggered PTEN reactivation and unleashed tumor suppressive activity.
appears to be a direct MYC (MYC proto-oncogene) target gene and was critical for MYC-driven tumorigenesis. We identified indole-3-carbinol, a compound found in cruciferous vegetables, as a natural and potent WWP1 inhibitor. Thus, our findings unravel a potential therapeutic strategy for cancer prevention and treatment through PTEN reactivation.
The cycling stability of lithium metal batteries is steadily improving. The safety issues, which mainly result from the employment of flammable solvents, should be strongly considered for practical ...Li metal batteries. Nonflammable solvents can mitigate fire hazards; however, their employment irreversibly deteriorates the cycling stability of working batteries owing to intrinsic high reactivity against Li metal. Herein, regulating solvation structure in a dimethylacetamide (DMAC)‐based electrolyte is proposed to achieve compatibility between cycling stability and nonflammability of electrolytes. DMAC, a nonflammable solvent, is employed to construct a nonflammable localized high‐concentration electrolyte (LHCE). In the DMAC‐based LHCE, there are abundant aggregate clusters resulting in the formation of anion‐derived solid electrolyte interphase to circumvent parasitic reactions between DMAC solvents and Li metal and to improve the uniformity of Li deposition, which ensures the compatibility between cycling stability under practical conditions and nonflammability of electrolytes. This work opens an emerging avenue to construct long‐cycling and safe Li metal batteries by manipulating solvation structure in nonflammable electrolytes.
Regulating solvation structure in a dimethylacetamide‐based nonflammable electrolyte is explored to achieve compatibility between cycling stability and safety of electrolytes for practical lithium metal batteries. In the localized high‐concentration electrolyte, aggregate clusters are generated and result in the formation of an anion‐derived solid electrolyte interphase, and also improve the uniformity of Li deposition.
Concerns have been raised regarding the potential association between proton pump inhibitor (PPI) use and dementia.
This study aimed to examine this association in an Asian population.
Patients ...initiating PPI therapy between January 1, 2000 and December 31, 2003 without a prior history of dementia were identified from Taiwan's National Health Insurance Research Database. The outcome of interest was all-cause dementia. Cox regression models were applied to estimate the hazard ratio (HR) of dementia. The cumulative PPI dosage stratified by quartiles of defined daily doses and adjusted for baseline disease risk score served as the primary variables compared against no PPI use.
We analyzed the data of 15726 participants aged 40 years or older and free of dementia at baseline. PPI users (n = 7863; average follow-up 8.44 years) had a significantly increased risk of dementia over non-PPI users (n = 7863; average follow-up 9.55 years) (adjusted HR aHR 1.22; 95% confidence interval: 1.05-1.42). A significant association was observed between cumulative PPI use and risk of dementia (P for trend = .013). Subgroup analysis showed excess frequency of dementia in PPI users diagnosed with depression (aHR 2.73 1.91-3.89), hyperlipidemia (aHR 1.81 1.38-2.38), ischemic heart disease (aHR 1.55 1.12-2.14), and hypertension (aHR 1.54 1.21-1.95).
An increased risk for dementia was identified among the Asian PPI users. Cumulative PPI use was significantly associated with dementia. Further investigation into the possible biological mechanisms underlying the relationship between dementia and PPI use is warranted.
A new Schottky junction ultraviolet photodetector (UVPD) is fabricated by coating a free‐standing ZnO nanorod (ZnONR) array with a layer of transparent monolayer graphene (MLG) film. The ...single‐crystalline 0001‐oriented ZnONR array has a length of about 8–11 μm, and a diameter of 100∼600 nm. Finite element method (FEM) simulation results show that this novel nanostructure array/MLG heterojunction can trap UV photons effectively within the ZnONRs. By studying the I–V characteristics in the temperature range of 80–300 K, the barrier heights of the MLG film/ZnONR array Schottky barrier are estimated at different temperatures. Interestingly, the heterojunction diode with typical rectifying characteristics exhibits a high sensitivity to UV light illumination and a quick response of millisecond rise time/fall times with excellent reproducibility, whereas it is weakly sensitive to visible light irradiation. It is also observed that this UV photodetector (PD) is capable of monitoring a fast switching light with a frequency as high as 2250 Hz. The generality of the above results suggest that this MLG film/ZnONR array Schottky junction UVPD will have potential application in future optoelectronic devices.
A new Schottky junction ultraviolet photodetector is fabricated by coating a free‐standing ZnO nanorod array with a monolayer graphene film. This special structure is able to trap UV light within ZnO nanorods, and exhibits high sensitivity to UV light irradiation with good reproducibility and fast response time.
Arm symmetrical PbS dendrite （ASD-PbS） nanostructures can be prepared on a large scale by a solvothermal process. The ASD-PbSs exhibit a three-dimensional symmetrical structure, and each dendrite ...grows multiple branches on the main trunk. Such unique ASD-PbSs can be combined with polyvinylidene fluoride （PVDF） to prepare a composite material with enhanced dielectric and microwave-absorption properties. A detailed investigation of the dependence of the dielectric properties on the frequency and temperature shows that the ASD-PbS/PVDF composite has an ultrahigh dielectric constant and a low percolation threshold. The dielectric permittivity is as high as 1,548 when the concentration of the ASD-PbS filler reaches 13.79 vol.% at 102 Hz, which is 150 times larger than that of pure PVDF, while the composite is as flexible as pure PVDF. Furthermore, the maximum reflection loss can reach -36.69 dB at 16.16 GHz with a filler content of only 2 wt.%, which indicates excellent microwave absorption. The loss mechanism is also elucidated. The present work demonstrates that the addition of metal sulfide microcrystals to polymer matrix composites provides a useful method for improving the dielectric and microwave-absorption properties.
Solar thermoelectric devices play a significant role in addressing the problem of global warming, owing to their unique features of converting both waste heat and solar energy directly into ...electricity. Herein, a flexible 3D Janus helical ribbon architecture is designed, starting from well‐aligned tellurium (Te) nanowire film, using an in situ redox process reacting with Ag+ and Cu2+ resulting in n‐type, p‐type, and photothermal sides in one film. Remarkably, the device shows all‐day electricity generation and large temperature gradient by coupling the cold side with a passive radiative cooling technique and the hot side with a selective solar absorption technique, showing a temperature gradient of 29.5 K, which is much higher than previously reported devices under a low solar radiation of only 614 W m−2. Especially, the device can still generate electricity even at night. The present strategy offers a new way for heat management by efficiently utilizing solar energy and the cold of the universe.
A solar thermoelectric generator is fabricated with outstanding temperature difference and the property of synergistic utilization of solar energy and waste heat by in situ redox reaction to construct n‐type, p‐type, and photothermal sides in one nanowire film that is the reverse side of passive radiative cooling film. The ordered nanowire film also imparts the solar thermoelectric generator with better thermoelectrical performance.
Severe cognitive decline is a hallmark of Alzheimer’s disease (AD). In addition to gray matter loss, significant white matter pathology has been identified in AD patients. Here, we characterized the ...dynamics of myelin generation and loss in the APP/PS1 mouse model of AD. Unexpectedly, we observed a dramatic increase in the rate of new myelin formation in APP/PS1 mice, reminiscent of the robust oligodendroglial response to demyelination. Despite this increase, overall levels of myelination are decreased in the cortex and hippocampus of APP/PS1 mice and postmortem AD tissue. Genetically or pharmacologically enhancing myelin renewal, by oligodendroglial deletion of the muscarinic M1 receptor or systemic administration of the pro-myelinating drug clemastine, improved the performance of APP/PS1 mice in memory-related tasks and increased hippocampal sharp wave ripples. Taken together, these results demonstrate the potential of enhancing myelination as a therapeutic strategy to alleviate AD-related cognitive impairment.
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•New myelin formation is increased in adult APP/PS1 mice•Extensive myelin loss occurs in APP/PS1 mice and individuals with AD•Pro-myelinating strategies enhance myelin renewal and alleviate myelin loss in APP/PS1 mice•Enhanced myelin renewal rescues deficits in cognition and hippocampal physiology in APP/PS1 mice
Chen et al. demonstrate that myelin formation is increased in APP/PS1 mice, reminiscent of a regenerative response to extensive demyelination, and that pro-myelinating strategies enhance myelin renewal, rescue cognitive deficits, and increase hippocampal sharp wave ripples in APP/PS1 mice.
The ubiquitin-proteasome system (UPS) and autophagy are two major quality control processes whose impairment is linked to a wide variety of diseases. The coordination between UPS and autophagy ...remains incompletely understood. Here, we show that ubiquitin ligase UBE3C and deubiquitinating enzyme TRABID reciprocally regulate K29/K48-branched ubiquitination of VPS34. We find that this ubiquitination enhances the binding of VPS34 to proteasomes for degradation, thereby suppressing autophagosome formation and maturation. Under ER and proteotoxic stresses, UBE3C recruitment to phagophores is compromised with a concomitant increase of its association with proteasomes. This switch attenuates the action of UBE3C on VPS34, thereby elevating autophagy activity to facilitate proteostasis, ER quality control and cell survival. Specifically in the liver, we show that TRABID-mediated VPS34 stabilization is critical for lipid metabolism and is downregulated during the pathogenesis of steatosis. This study identifies a ubiquitination type on VPS34 and elucidates its cellular fate and physiological functions in proteostasis and liver metabolism.
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