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Sn-doped indium oxide (ITO) semiconductor nano-films are fabricated by plasma-enhanced atomic layer deposition using trimethylindium (TMIn), tetrakis(dimethylamino)tin (TDMASn), and O2plasma as the sources of In, Sn and O, respectively. A shared temperature window of 150 °C- 200 °C is observed for the deposition of ITO nano-films. The introduction of Sn into indium oxide is found to increase the concentration of oxygen into the ITO films and inhibit crystallization. Furthermore, two oxidation states are observed for In and Sn, respectively. With the increment of interfaces of In-O/Sn-O in the ITO films, the relative percentage of In3+ions increases and that of Sn4+decreases, which is generated by interfacial competing reactions. By optimizing the channel component, the In0.77Sn0.23O1.11thin-film transistors (TFTs) demonstrate high performance, includingµFEof 52.7 cm2V-1s-1, and a highION/IOFFof â¼5 × 109. Moreover, the devices show excellent positive bias temperature stress stability at 3 MV cm-1and 85 °C, i.e. a minimalVthshift of 0.017 V after 4 ks stress. This work highlights the successful application of ITO semiconductor nano-films by ALD for TFTs.
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OBJECTIVE: Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) is highly expressed in inflamed mucosa of inflammatory bowel disease (IBD) and negatively regulates immune response, while the underlying mechanisms regulating mucosal macrophage functions remain unknown. Here, we investigated the roles of MCPIP1 in modulating the differentiation and functions of intestinal macrophages in the pathogenesis of IBD. DESIGN: ScRNA-seq was used to cluster the monocyte/macrophage lineage from macrophage-specific Mcpip1-deficient (Mcpip1 ∆Mye) mice and Mcpip1 fl/fl littermates. The differentially expressed genes were confirmed by RNA-seq, luciferase assay, CUT&Tag assay and Western blotting. Effects of MCPIP1 and the activating transcription factor 3 (ATF3)-AP1S2 axis were assessed in patients with IBD. RESULTS: Mcpip1 ∆Mye mice developed more severe dextran sulfate sodium (DSS)-induced colitis characterised by an increase in macrophage migratory capacity and M1 macrophage polarisation but a decrease in the monocyte-to-macrophage maturation in gut mucosa compared with their littermates. ScRNA-seq unravelled a proinflammatory population (Ccr2+Il-1ß+Tlr2+Cx3cr1-Cd163-Mrc1-Ly6c+) of the monocyte/macrophage lineage from lamina propria CD11b+ cells and an arrest of Mcpip1 ∆Mye monocyte-to-macrophage maturation in an Atf3-Ap1s2 axis-dependent manner. Silencing of Ap1s2 or Atf3 markedly suppressed Mcpip1 ∆Mye macrophage migration, M1-like polarisation, and production of proinflammatory cytokines and chemokines. Notably, in vivo blockage of Ap1s2 ameliorated DSS-induced colitis in Mcpip1 ΔMye mice through enhancing intestinal macrophage maturation. Furthermore, MCPIP1, ATF3 and AP1S2 were highly expressed in inflamed mucosa of active patients with IBD and blockage of ATF3 or AP1S2 significantly suppressed IBD CD14+-derived M1-like macrophage polarisation and proinflammatory cytokine production. CONCLUSIONS: Macrophage-specific Mcpip1 deficiency polarises macrophages towards M1-like phenotype, arrests macrophage maturation and exacerbates intestinal inflammation in an Atf3-Ap1s2-dependent manner, thus providing novel mechanistic insight into intestinal macrophage functions during IBD.
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Colitis , Enfermedades Inflamatorias del Intestino , Ribonucleasas , Animales , Ratones , Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , Quimiocina CCL2/metabolismo , Colitis/patología , Sulfato de Dextran/farmacología , Inflamación/metabolismo , Mucosa Intestinal/metabolismo , Macrófagos , Ratones Endogámicos C57BL , Monocitos , Ribonucleasas/metabolismoRESUMEN
The pathophysiological mechanism of hepatic fibrosis (HF) is related to the excessive activation of the DNA repair enzyme poly ADP-ribose polymerase-1 (PARP-1). The drugs, targeting PARP-1, are scarce. Therefore, the lead compound, moderately inhibiting PARP-1, with anti-HF properties should be identified. This study screened dihydrokaempferol (DHK) from herbs based on preliminary studies to intervene in a CCl4-induced liver injury and HF model in mice. In vitro, the expression levels of PARP-1-regulated related proteins and phosphorylation were examined. The binding pattern of DHK and PARP-1 was analyzed using molecular docking and molecular dynamics platforms. The results showed that DHK could significantly attenuate CCl4-induced liver injury and HF in mice. Moreover, it could also attenuate the toxic effects of CCl4 on HepG2 and inhibit α-SMA and Collagen 1/3 synthesis of LX-2 cells in-vitro. Molecular docking revealed that DHK could competitively bind to the Glu-988 and His-862 residues of the upstream DNA repair enzyme PARP-1, moderately inhibiting its overactivation. This led to maintaining NAD+ levels and energy metabolism in hepatocytes and inhibiting the activation of PARP-1-regulated downstream signaling pathways (TGF-ß1, etc.), related proteins (p-Smd2/3, etc.), and inflammatory mediators while acting indirectly. Thus, DHK could attenuate CCl4-induced liver injury and HF in mice in a different mechanism from those of the existing reported flavonoids. It was associated with inhibiting the expression of downstream pathways and related cytokines by competitively binding to PARP-1. This study might provide a basis and direction for the design and exploration of anti-HF lead compounds.
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Enfermedad Hepática Crónica Inducida por Sustancias y Drogas , Citocinas , Animales , Ratones , Tetracloruro de Carbono/toxicidad , Enfermedad Hepática Crónica Inducida por Sustancias y Drogas/metabolismo , Enfermedad Hepática Crónica Inducida por Sustancias y Drogas/patología , Citocinas/metabolismo , Flavonoides/farmacología , Células Estrelladas Hepáticas , Cirrosis Hepática/inducido químicamente , Cirrosis Hepática/tratamiento farmacológico , Cirrosis Hepática/prevención & control , Simulación del Acoplamiento Molecular , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Ferroelectric field effect transistor (FeFET) memories with hafnium zirconium oxide (HZO) ferroelectric gate dielectric and ultrathin InOxchannel exhibit promising applicability in monolithic three-dimensional (M3D) integrated chips. However, the inferior stability of the devices severely limits their applications. In this work, we studied the effect of single cycle of atomic-layer-deposited Al-O bonds repeatedly embedded into an ultrathin InOxchannel (â¼2.8 nm) on the Hf0.45Zr0.55OxFeFET memory performance. Compared to the pure InOxchannel, three cycles of Al-O bonds modified InOxchannel (IAO-3) generates a much larger memory window (i.e. drain current ratio between the programmed and erased devices) under the same program conditions (+5.5 V/500 ns), especially after post-annealing at 325 °C for 180 s in O2(1238 versus 317). Meanwhile, the annealed IAO-3 FeFET memory also shows quite stable data retention up to 104s, and much more robust program/erase stabilities till 105cycles. This is because the modification of strong Al-O bonds stabilizes the oxygen vacancies and reduces the bulk trap density in the channel. Furthermore, it is indicated that the program and erase efficiencies increase gradually with reducing the channel length of the memory device. By demonstrating markedly improved performance of the HZO FeFET memory with the ultrathin IAO-3 channel, this work provides a promising device for M3D integratable logic and memory convergent systems.
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BACKGROUND: H19 is the first long noncoding RNA (lncRNA) found to be associated with gene imprinting. It is highly expressed in the embryonic stage and may have important regulatory effects on human embryonic development. We investigated the differences between the levels of H19 promoter DNA methylation in the chorionic villi of patients who experienced spontaneous abortion (SA) following in vitro fertilization embryo transfer (IVF-ET) and those of patients with a normal early pregnancy (NEP). We also analyzed the associated DNA methyltransferase (DNMT) activity. METHODS: Chorionic villus tissue from patients with SA and NEP were collected. The DNA methylation levels of two CpG islands in the promoter region of the H19 gene in the two groups were detected by bisulfite sequencing, and the mRNA expression of DNMTs was analyzed by real-time polymerase chain reaction. RESULTS: The sample size of each group was 32, and there were no significant differences in baseline data, including age, parity, and body mass index, between the two groups. Among the 7 CpG islands measured, the methylation rates of 3 CpG islands (CpG 1, 6, and 7) were significantly lower in the SA group than in the NEP group (P < 0.01). The methylation levels of the other 4 CpG islands were not significantly different between the two groups. There were no differences in the expression of DNMT1 between the two groups (P > 0.05), but DNMT3a and DNMT3b RNA levels were significantly lower in SA group than in the NEP group (P < 0.01). CONCLUSIONS: The lower H19 promoter DNA methylation levels found in the chorionic villi of patients with SA patients following IVF-ET may be explained by decreased expression of DNMT3a and DNMT3b.
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Metilación de ADN , Fertilización In Vitro , Impresión Genómica , Femenino , Humanos , Embarazo , Transferencia de Embrión , Regiones Promotoras Genéticas , Aborto EspontáneoRESUMEN
In order to imitate brain-inspired biological information processing systems, various neuromorphic computing devices have been proposed, most of which were prepared on rigid substrates and have energy consumption levels several orders of magnitude higher than those of biological synapses (â¼10 fJ per spike). Herein, a new type of wearable organic ferroelectric artificial synapse is proposed, which has two modulation modes (optical and electrical modulation). Because of the high photosensitivity of organic semiconductors and the ultrafast polarization switching of ferroelectric materials, the synaptic device has an ultrafast operation speed of 30 ns and an ultralow power consumption of 0.0675 aJ per synaptic event. Under combined photoelectric modulation, the artificial synapse realizes associative learning. The proposed artificial synapse with ultralow power consumption demonstrates good synaptic plasticity under different bending strains. This provides new avenues for the construction of ultralow power artificial intelligence system and the development of future wearable devices.
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Inteligencia Artificial , Dispositivos Electrónicos Vestibles , Encéfalo , Plasticidad Neuronal , SinapsisRESUMEN
At present, the molecular mechanisms underlying inflammation remain unclear. In recent years, research on inflammation has focused on stimulating cell inflammation by using exogenous pro-inflammatory substances such as lipopolysaccharide (LPS) or inflammatory factors. To investigate the molecular mechanism of inflammation from a new perspective, we designed a nucleic acid nanoflowers (NFs) complex to directly activate inflammatory genes to study the inflammatory response without the need for external microbial factors to trigger an inflammatory response. An RNAa-type target gene-activated NFs was designed. Human umbilical vein endothelial cells (HUVECs) were transfected with NFs carrying small activating RNA (saRNAs) to directly co-activate microRNA (miR)-155 and SHIP1 genes. After RNA activation (RNAa)-type NFs were transferred into HUVECs, the expression of miR-155 and pro-inflammatory and cancer-related factors increased, anti-inflammatory factors were reduced, cell proliferation increased, and cell migration was promoted. IL-1ß protein levels were decreased and SHIP1 expression was downregulated. When miR-155 and its target SHIP1 were both activated, the expression of both was unaltered, maintaining cell homeostasis. This points towards miR-155 overexpression can trigger inflammation, and that miR-155 and its target genes act as a molecular switch role in the development of inflammation.
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MicroARNs , Ácidos Nucleicos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Inflamación/genética , Inflamación/metabolismo , Lipopolisacáridos , MicroARNs/genética , MicroARNs/metabolismo , Ácidos Nucleicos/metabolismoRESUMEN
BACKGROUND & AIMS: As a susceptibility gene for human inflammatory bowel diseases (IBD), how avian erythroblastosis virus E26 oncogene homolog-1 (ETS-1) modulates intestinal mucosal immune response remains unclear. Here we studied the potential roles of ETS-1 in the pathogenesis of IBD. METHODS: ETS-1 expression was examined in IBD patients. CD45RBhighCD4+ T cell-transfer colitis, dextran sulfate sodium (DSS)-induced colitis, and azomethane (AOM)/DSS-induced colitis-associated cancer (CAC) models were constructed to probe the function of ETS-1 in vivo. RNA-sequencing of CD4+ T cells from Ets-1 transgenic (Tg) mice was performed to decipher the key differentially expressed genes. Adenovirus transduction was conducted to verify the therapeutic potentials of ETS-1 in vivo. RESULTS: ETS-1 expression was significantly increased in CD4+ T cells from active IBD patients compared with healthy controls, which was upregulated by TNF-α but markedly suppressed by anti-TNF-α mAb therapy. More severe colitis was observed in Rag1-/- mice reconstituted with Ets-1TgCD45RBhighCD4+ T cells or in Ets-1 Tg mice after DSS exposure compared with controls, characterized by higher TNF-α and IFN-γ expression in inflamed colon. Ets-1 Tg mice were more prone to develop AOM/DSS-induced CAC, and bone marrow chimeras further proved that lamina propria immune cells but not intestinal epithelial cells contributed to the development of colitis. RNA-sequencing and luciferase analysis revealed cold-inducible RNA-binding protein (CIRBP) as a functional target of ETS-1 to promote Th1 cell-driven immune response. Consistently, intraperitoneal administration of adenovirus-m-cirbp-shRNA ameliorated trinitrobenzene sulfonic acid (TNBS)-induced colitis of Ets-1 Tg mice. CONCLUSIONS: Our data identify that ETS-1 is highly expressed in IBD patients and promotes Th1-driven mucosal inflammation through CIRBP. CIRBP may serve as a novel therapeutic target for treatment of human IBD.
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Colitis , Enfermedades Inflamatorias del Intestino , Proteína Proto-Oncogénica c-ets-1 , Proteínas de Unión al ARN , Células TH1 , Animales , Humanos , Ratones , Colitis/inducido químicamente , Colitis/genética , Colitis/inmunología , Modelos Animales de Enfermedad , Inflamación , Enfermedades Inflamatorias del Intestino/genética , Enfermedades Inflamatorias del Intestino/inmunología , Ratones Transgénicos , Oncogenes , ARN , Proteínas de Unión al ARN/genética , Células TH1/inmunología , Inhibidores del Factor de Necrosis Tumoral , Proteína Proto-Oncogénica c-ets-1/genéticaRESUMEN
Nanozymes with wide applications have rapidly attracted tremendous attention from various fields in the last decade. However, research on the standardization of nanozymes is still lacking. Currently, the accurate evaluation and effective tracing of the enzyme-like activity of nanozymes have become a common concern. This work aims to develop a certified reference material (CRM) of Prussian blue nanozymes (PBNEs) for their peroxidase (POD)-like activity. The homogeneity and stability studies demonstrated that the property value of POD-like activity is consistent across different packing units, and remains unchanged during the one-year validity period of storage in the dark at 4 °C. The certified value of the POD-like activity of the PBNE CRM is assigned as 174 ± 13 U mg-1 (k = 2) by interlaboratory comparison studies and traceable uncertain evaluation. Furthermore, the need for quality control of the POD-like activity of nanozymes was exemplified by comparing the influence of two additional PBNEs on the dry and wet chemical detection of glucose (Glu). As the first quality assurance tool of nanozymes, the PBNE CRM is expected to replace natural horse radish peroxidase (HRP) as an effective benchmark for assessing the analytical method and laboratory competence. In addition, this work also inspires the further standardization of nanozymes.
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Antioxidantes , Ferrocianuros , Glucosa , Peroxidasas , CatálisisRESUMEN
Covalent-organic frameworks (COFs) are a new class of porous crystalline frameworks with high π-conjugation and periodical skeletons. The highly ordered π-conjugation structures in some COFs allow exciton migration and energy transfer over the frameworks, which leads to good fluorescence probing ability. In this work, two COFs (TFHPB-TAPB-COF and TFHPB-TTA-COF) are successfully condensed via the Schiff base condensation reaction. The intramolecular hydrogen bonds between imine bonds and hydroxyl groups form the excited-state intramolecular proton transfer (ESIPT) strategy. Owing to intramolecular hydrogen bonds in the skeleton, the two COFs show high crystallinity, remarkable stability, and excellent luminescence. The COFs represent a good sensitivity and selectivity to fluoride anions via fluorescence turn-off. Other halogen anions (chloride, bromide, and iodine) and acid anions (nitrate and hydrogen carbonate) remain inactive. These results imply that only fluoride anion is capable of opening the hydrogen bond interaction and hence break the ESIPT strategy. The detection limit toward fluoride anion is down to nanomoles level, ranking the best performances among fluoride anion sensors systems.
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Halide perovskites are promising photoactive materials for filter-free color-imaging sensors owing to their outstanding optoelectronic properties, tunable bandgaps, and suitability for large-scale fabrication. However, producing patterned perovskite films of sufficiently high quality for such applications poses a challenge for existing fabrication methods: using solution processes to prepare patterned perovskite films is complicated, while evaporation methods often result in perovskite photodetectors with limited performance. In this paper, the authors report the development of an improved evaporation method in which substrates are treated with a brominated (3-aminopropyl) triethoxysilane self-assembled monolayer to improve the properties of the patterned perovskite films. The resulting perovskite photodetectors exhibit significantly enhanced photosensitivity and long-term stability (exceeding 100 days). Additionally, the polymer substrates facilitate device flexibility. Finally, perovskites comprising three different halide components, each with a different bandgap, are integrated into a device array using the developed evaporation technology, yielding sensors that enable the discrimination of red, green, and blue colors. Thus, the flexible photosensor arrays can generate colorful images closely resembling perceived patterns, demonstrating reliable color imaging. Therefore, this study successfully demonstrates filter-free color-imaging by integrating high-performance patterned and multicomponent perovskite photodetectors, highlighting the potential of such detectors for advanced optoelectronic applications, including hyperspectral imaging.
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5-Fluorouracil (5-FU)-based chemotherapy is the first-line recommended regimen in colorectal cancer (CRC), but resistance limits its clinical application. Andrographolide sulfonate, a traditional Chinese medicine, is mainly used to treat infectious diseases. In the present study, we reported that andrographolide sulfonate could significantly inhibit the growth of transplanted CT26 colon cancer in mice and improve survival when combined with 5-FU. Furthermore, TUNEL assay and immunohistochemistry analysis of proliferating cell nuclear antigen, Ki-67 and p-STAT3 confirmed that co-treatment could inhibit tumor proliferation and promote apoptosis. In tumor tissues of groups that received 5-FU and andrographolide sulfonate, CD4+ and CD8+ T cell infiltration was increased, and the expression of IFN-γ and Granzyme B detected by immunohistochemistry and qPCR was upregulated, reflecting improved antitumor immunity. Finally, we verified that 5-FU significantly activated the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in myeloid-derived suppressor cells (MDSCs) and that andrographolide sulfonate reversed this process to sensitize cells to 5-FU. In summary, andrographolide sulfonate synergistically enhanced antitumor effects and improved antitumor immunity by inhibiting 5-FU-induced NLRP3 activation in MDSCs. These findings provide a novel strategy to address 5-FU resistance in the treatment of CRC.
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Antiinflamatorios/administración & dosificación , Antimetabolitos Antineoplásicos/administración & dosificación , Diterpenos/administración & dosificación , Fluorouracilo/administración & dosificación , Células Supresoras de Origen Mieloide/efectos de los fármacos , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Animales , Línea Celular Tumoral , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Sinergismo Farmacológico , Femenino , Ratones , Ratones Endogámicos BALB C , Células Supresoras de Origen Mieloide/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismoRESUMEN
The electronic-photonic convergent systems can overcome the data transmission bottleneck for microchips by enabling processor and memory chips with high-bandwidth optical input/output. However, current silicon-based electronic-photonic systems require various functional devices/components to convert high-bandwidth optical signals into electrical ones, thus making further integrations of sophisticated systems rather difficult. Here, we demonstrate thin-film transistor-based photoelectric memories employing CsPbBr3/CsPbI3 blend perovskite quantum dots (PQDs) as a floating gate, and multilevel memory cells are achieved under programming and erasing modes, respectively, by imputing high-bandwidth optical signals. For different bandwidth light input (i.e. 500-550, 575-650 and 675-750 nm) with the same intensity, three levels of programming window (i.e. 3.7, 1.9 and 0.8 V) and erasing window (i.e. -1.9, -0.6 and -0.1 V) are obtained under electrical pulses, respectively. This is because the blend PQDs have two different bandgaps, and different amounts of photo-generated carriers can be produced for different wavelength optical inputs. It is noticed that the 675-750 nm light inputs have no effects on both programming and erasing windows because of no photo-carriers generation. Four memory states are demonstrated, showing enough large gaps (1.12-5.61 V) between each other, good data retention and programming/erasing endurance. By inputting different optical signals, different memory states can be switched easily. Therefore, this work directly demonstrates high-bandwidth light inputting multilevel memory cells for novel electronic-photonic systems.
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We report on the study of both perpendicular magnetic anisotropy (PMA) and Dzyaloshinskii-Moriya interaction (DMI) at an oxide/ferromagnetic metal (FM) interface, i.e., BaTiO_{3} (BTO)/CoFeB. Thanks to the functional properties of the BTO film and the capability to precisely control its growth, we are able to distinguish the dominant role of the oxide termination (TiO_{2} vs BaO) from the moderate effect of ferroelectric polarization in the BTO film, on the PMA and DMI at an oxide/FM interface. We find that the interfacial magnetic anisotropy energy of the BaO-BTO/CoFeB structure is 2 times larger than that of the TiO_{2}-BTO/CoFeB, while the DMI of the TiO_{2}-BTO/CoFeB interface is larger. We explain the observed phenomena by first principles calculations, which ascribe them to the different electronic states around the Fermi level at oxide/ferromagnetic metal interfaces and the different spin-flip process. This study paves the way for further investigation of the PMA and DMI at various oxide/FM structures and thus their applications in the promising field of energy-efficient devices.
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Recently, various two-dimensional materials have been reported to exhibit non-volatile resistance switching phenomenon. The atomristors, featuring memristor effect in atomically thin nanomaterials such as monolayer transition metal dichalcogenides and hexagonal boron nitride, have drawn much attention due to the extremely thin active layer thickness with the advantages of forming-free characteristic, large on/off resistance ratio and fast switching speed. To investigate the switching mechanisms in the 2D monolayers, we introduced an electrical characterization method by current sweeping to illustrate the detailed information hidden in the commonly used voltage-sweep curves. Multiple transition steps have been observed in the SET process of MoS2-based resistance switching devices. The different behaviors of transition steps were attributed to the number of defects or vacancies associated with the switching phenomenon, which is consistent with the previously reported conductive-bridge-like model for 2D atomristors. This work provides an approach using current sweeping to precisely characterize the resistance switching effect and inspires further research to optimize the defect distribution in 2D materials for the applications in multi-bit non-volatile memory and neuromorphic computing.
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We report on a new family of argyrodite lithium superionic conductors, as solid solutions Li6+xMxSb1-xS5I (M = Si, Ge, Sn), that exhibit superionic conductivity. These represent the first antimony argyrodites to date. Exploration of the series using a combination of single crystal X-ray and synchrotron/neutron powder diffraction, combined with impedance spectroscopy, reveals that an optimal degree of substitution (x), and substituent induces slight S2-/I- anion site disorder-but more importantly drives Li+ cation site disorder. The additional, delocalized Li-ion density is located in new high energy lattice sites that provide intermediate interstitial positions (local minima) for Li+ diffusion and activate concerted ion migration, leading to a low activation energy of 0.25 eV. Excellent room temperature ionic conductivity of 14.8 mS·cm-1 is exhibited for cold-pressed pellets-up to 24 mS·cm-1 for sintered pellets-among the highest values reported to date. This enables all-solid-state battery prototypes that exhibit promising properties. Furthermore, even at -78 °C, suitable bulk ionic conductivity of the electrolyte is retained (0.25 mS·cm-1). Selected thioantimonate iodides demonstrate good compatibility with Li metal, sustaining over 1000 h of Li stripping/plating at current densities up to 0.6 mA·cm-2. The significantly enhanced Li ion conduction and lowered activation energy barrier with increasing site disorder reveals an important strategy toward the development of superionic conductors.
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Graphene aerogel fibers (GAFs) with low density, high specific surface area, and high porosity can be used as the host material to incorporate another component and thus form multifunctional fibers, which have potential applications in wearable devices, thermoregulating apparatus, sensors, and so forth. However, the intrinsically low electric conductivity of GAFs hampers them in the fields of electrothermal heating and electromagnetic interference (EMI) shielding. Herein, we report a new aerogel fiber composed by graphene sheets and nickel nanoparticles with low density (55-192 mg/cm3), high electric conductivity (0.8 × 103 to 4.5 × 104 S/m), and high specific surface area (49-105 m2/g). The graphene/Ni aerogel fibers (GNAFs) were synthesized initially from reduced graphene oxide hydrogel fibers followed by an electroless plating process. Further investigations have demonstrated that the resulting GNAFs possess excellent electrothermal property, faster electrothermal response, high mechanical and electrical stability as the electric wire, and excellent EMI shielding performance as the composite filler. The saturated temperature of GNAFs can reach 174 °C with an applied voltage of only 5 V, and the heating rate surpasses those of commercial Kanthal and Nichrome wires about 2.1 times and 2.6 times, respectively. The EMI shielding effectiveness of GNAFs is higher than 30 dB at the long bandwidth of 12.5-20 GHz. Specifically, it can shield more than 99.99% of the incident wave at the bandwidth of 15-20 GHz.
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Recently, two-dimensional (2D) atomic sheets have inspired new ideas in nanoscience including topologically protected charge transport,1,2 spatially separated excitons,3 and strongly anisotropic heat transport.4 Here, we report the intriguing observation of stable nonvolatile resistance switching (NVRS) in single-layer atomic sheets sandwiched between metal electrodes. NVRS is observed in the prototypical semiconducting (MX2, M = Mo, W; and X = S, Se) transitional metal dichalcogenides (TMDs),5 which alludes to the universality of this phenomenon in TMD monolayers and offers forming-free switching. This observation of NVRS phenomenon, widely attributed to ionic diffusion, filament, and interfacial redox in bulk oxides and electrolytes,6-9 inspires new studies on defects, ion transport, and energetics at the sharp interfaces between atomically thin sheets and conducting electrodes. Our findings overturn the contemporary thinking that nonvolatile switching is not scalable to subnanometre owing to leakage currents.10 Emerging device concepts in nonvolatile flexible memory fabrics, and brain-inspired (neuromorphic) computing could benefit substantially from the wide 2D materials design space. A new major application, zero-static power radio frequency (RF) switching, is demonstrated with a monolayer switch operating to 50 GHz.
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Distinguishable detection of the ultraviolet, visible, and infrared spectrum is promising and significant for the super visual system of artificial intelligences. However, it is challenging to provide a photosensor with such broad spectral response ability. In this work, the ultraviolet, visible, and infrared spectrum is distinguished by developing serial photosensors based on perovskite/carbon nanotube hybrids. Oraganolead halide perovskites (CH3 NH3 PbX3 ) possess remarkable optoelectronic properties and tunable optical band gaps by changing the halogens, and integration with single-walled carbon nanotubes can further improve their photoresponsivities. The CH3 NH3 PbCl3 -based photosensor shows a responsivity up to 105 A W-1 to ultraviolet and no obvious response to visible light, which is superior to that of most ultraviolet sensors. The CH3 NH3 PbBr3 -based photosensor exhibits a high responsivity to visible light. Serial devices of the two hybrid photosensors with comparable electric and sensory performances can distinguish the spectrum of ultraviolet, visible, and infrared even with varying light intensities. The photosensors also demonstrate excellent mechanical flexibility and bending stability. By taking full advantages of the oraganolead halide perovskites, this work provides flexible high-responsivity photosensors specialized for ultraviolet, and gives a simple strategy for distinguishable detection of ultraviolet, visible, and infrared spectrum based on the serial flexible photosensors.
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Bulk graphene aerogels with high electrical conductivity, ultralow density, and high specific surface area have attracted significant attention because of their fascinating performances in energy storage, catalysis, absorption, sensor, electromagnetic shielding, etc. However, graphene aerogel microgranules (i.e., reducing the size of the bulk aerogels into microscale) and their performances in the electromagnetic field have been ignored. Herein, we report a new strategy to make floatable graphene aerogel microgranules with high hydrophobicity (137°), low density (13.5 mg/cm3), and high specific surface area (516 m2/g). These microgranules were synthesized initially from reduced graphene oxide (rGO) hydrogel microparticles and then in situ-modified by silica nanoparticles. Further investigations have demonstrated that the resulting silica-modified rGO aerogel microgranules possess highly efficient static electromagnetic screening (average 30.3 dB in 8-18 GHz) and dynamic infrared shielding (higher than 10 dB during floatation in air for 15 min) properties. The work reported here should give much inspiration to make more functional aerogel microgranules used in various emerging fields.