Showing papers by "Jun Chen published in 2020"
TL;DR: The present work provides a rationale based approach for the selection of drugs with potential antiviral activity for SARS-CoV-2 infection better than the investigational drug/divdivRemdesivir and other antiviral drugs/drug combinations being evaluated.
1,394 citations
TL;DR: The reaction mechanism, the rate-determining steps, and the key factors that control the activity and selectivity are analyzed from both experimental and theoretical studies to develop a fundamental understanding of the CO2 RR-to-CO process on SACs.
Abstract: The electrochemical CO2 reduction reaction (CO2 RR) is of great importance to tackle the rising CO2 concentration in the atmosphere. The CO2 RR can be driven by renewable energy sources, producing precious chemicals and fuels, with the implementation of this process largely relying on the development of low-cost and efficient electrocatalysts. Recently, a range of heterogeneous and potentially low-cost single-atom catalysts (SACs) containing non-precious metals coordinated to earth-abundant elements have emerged as promising candidates for the CO2 RR. Unfortunately, the real catalytically active centers and the key factors that govern the catalytic performance of these SACs remain ambiguous. Here, this ambiguity is addressed by developing a fundamental understanding of the CO2 RR-to-CO process on SACs, as CO accounts for the major product from CO2 RR on SACs. The reaction mechanism, the rate-determining steps, and the key factors that control the activity and selectivity are analyzed from both experimental and theoretical studies. Then, the synthesis, characterization, and the CO2 RR performance of SACs are discussed. Finally, the challenges and future pathways are highlighted in the hope of guiding the design of the SACs to promote and understand the CO2 RR on SACs.
296 citations
TL;DR: The deep learning model showed a comparable performance with expert radiologist, and greatly improve the efficiency of radiologists in clinical practice, holds great potential to relieve the pressure of frontline radiologists, improve early diagnosis, isolation and treatment, and thus contribute to the control of the epidemic.
Abstract: Background Computed tomography (CT) is the preferred imaging method for diagnosing 2019 novel coronavirus (COVID19) pneumonia. Our research aimed to construct a system based on deep learning for detecting COVID-19 pneumonia on high resolution CT, relieve working pressure of radiologists and contribute to the control of the epidemic. Methods For model development and validation, 46,096 anonymous images from 106 admitted patients, including 51 patients of laboratory confirmed COVID-19 pneumonia and 55 control patients of other diseases in Renmin Hospital of Wuhan University (Wuhan, Hubei province, China) were retrospectively collected and processed. Twenty-seven consecutive patients undergoing CT scans in Feb, 5, 2020 in Renmin Hospital of Wuhan University were prospectively collected to evaluate and compare the efficiency of radiologists against 2019-CoV pneumonia with that of the model. Findings The model achieved a per-patient sensitivity of 100%, specificity of 93.55%, accuracy of 95.24%, PPV of 84.62%, and NPV of 100%; a per-image sensitivity of 94.34%, specificity of 99.16%, accuracy of 98.85%, PPV of 88.37%, and NPV of 99.61% in retrospective dataset. For 27 prospective patients, the model achieved a comparable performance to that of expert radiologist. With the assistance of the model, the reading time of radiologists was greatly decreased by 65%. Conclusion The deep learning model showed a comparable performance with expert radiologist, and greatly improve the efficiency of radiologists in clinical practice. It holds great potential to relieve the pressure of frontline radiologists, improve early diagnosis, isolation and treatment, and thus contribute to the control of the epidemic.
289 citations
TL;DR: The deep learning model showed a comparable performance with expert radiologist, and greatly improved the efficiency of radiologists in clinical practice, to construct a system based on deep learning for detecting COVID-19 pneumonia on high resolution CT.
Abstract: Computed tomography (CT) is the preferred imaging method for diagnosing 2019 novel coronavirus (COVID19) pneumonia. We aimed to construct a system based on deep learning for detecting COVID-19 pneumonia on high resolution CT. For model development and validation, 46,096 anonymous images from 106 admitted patients, including 51 patients of laboratory confirmed COVID-19 pneumonia and 55 control patients of other diseases in Renmin Hospital of Wuhan University were retrospectively collected. Twenty-seven prospective consecutive patients in Renmin Hospital of Wuhan University were collected to evaluate the efficiency of radiologists against 2019-CoV pneumonia with that of the model. An external test was conducted in Qianjiang Central Hospital to estimate the system’s robustness. The model achieved a per-patient accuracy of 95.24% and a per-image accuracy of 98.85% in internal retrospective dataset. For 27 internal prospective patients, the system achieved a comparable performance to that of expert radiologist. In external dataset, it achieved an accuracy of 96%. With the assistance of the model, the reading time of radiologists was greatly decreased by 65%. The deep learning model showed a comparable performance with expert radiologist, and greatly improved the efficiency of radiologists in clinical practice.
267 citations
TL;DR: Wang et al. as discussed by the authors characterized the CT imaging and clinical course of asymptomatic cases with COVID-19 pneumonia and found that the predominant feature of CT findings in this cohort was ground glass opacity (GGO) with peripheral (44, 75.9%) distribution, unilateral location (34, 58.6%), often accompanied by characteristic signs.
241 citations
TL;DR: An electrocatalyst consisting of PdCu alloy nanoparticles on TiO2 nanosheets has been shown to directly couple N2 and CO2 in H2O to produce urea under ambient conditions.
Abstract: The use of nitrogen fertilizers has been estimated to have supported 27% of the world’s population over the past century. Urea (CO(NH2)2) is conventionally synthesized through two consecutive industrial processes, N2 + H2 → NH3 followed by NH3 + CO2 → urea. Both reactions operate under harsh conditions and consume more than 2% of the world’s energy. Urea synthesis consumes approximately 80% of the NH3 produced globally. Here we directly coupled N2 and CO2 in H2O to produce urea under ambient conditions. The process was carried out using an electrocatalyst consisting of PdCu alloy nanoparticles on TiO2 nanosheets. This coupling reaction occurs through the formation of C–N bonds via the thermodynamically spontaneous reaction between *N=N* and CO. Products were identified and quantified using isotope labelling and the mechanism investigated using isotope-labelled operando synchrotron-radiation Fourier transform infrared spectroscopy. A high rate of urea formation of 3.36 mmol g–1 h–1 and corresponding Faradic efficiency of 8.92% were measured at –0.4 V versus reversible hydrogen electrode. Conventionally, urea is synthesized via two consecutive processes, N2 + H2 → NH3 followed by NH3 + CO2. Now, an electrocatalyst consisting of PdCu alloy nanoparticles on TiO2 nanosheets has been shown to directly couple N2 and CO2 in H2O to produce urea under ambient conditions.
209 citations
TL;DR: A series of atomic Fe catalysts with adjustable ND-Fe coordination are synthesized, which verify that ORR performance highly depends on the concentration of e-ND-Fe species, and will guide to develop highly active atomic metal catalysts through rational defect engineering.
Abstract: Controllably constructing nitrogen-modified divacancies (ND) in carbon substrates to immobilize atomic Fe species and unveiling the advantageous configuration is still challenging, but indispensable for attaining optimal Fe-N-C catalysts for the oxygen reduction reaction (ORR). Herein, a fundamental investigation of unfolding intrinsically superior edge-ND trapped atomic Fe motifs (e-ND-Fe) relative to an intact center model (c-ND-Fe) in ORR electrocatalysis is reported. Density functional theory calculations reveal that local electronic redistribution and bandgap shrinkage for e-ND-Fe endow it with a lower free-energy barrier toward direct four-electron ORR. Inspired by this, a series of atomic Fe catalysts with adjustable ND-Fe coordination are synthesized, which verify that ORR performance highly depends on the concentration of e-ND-Fe species. Remarkably, the best e-ND-Fe catalyst delivers a favorable kinetic current density and halfwave potential that can be comparable to benchmark Pt-C under acidic conditions. This work will guide to develop highly active atomic metal catalysts through rational defect engineering.
191 citations
TL;DR: In this article, the authors focus on recent progress in improving the catalytic properties of transition metal dichalcogenides (TMDs) toward highly efficient production of H2.
Abstract: The hydrogen evolution reaction (HER) is an emerging key technology to provide clean, renewable energy. Current state-of-the-art catalysts still rely on expensive and rare noble metals, however, the relatively cheap and abundant transition metal dichalcogenides (TMDs) have emerged as exceptionally promising alternatives. Early studies in developing TMD-based catalysts laid the groundwork in understanding the fundamental catalytically active sites of different TMD phases, enabling a toolbox of physical, chemical, and electronic engineering strategies to improve the HER catalytic activity of TMDs. This report focuses on recent progress in improving the catalytic properties of TMDs toward highly efficient production of H2. Combining theoretical and experimental considerations, a summary of the progress to date is provided and a pathway forward for viable hydrogen evolution from TMD driven catalysis is concluded.
160 citations
Chinese Academy of Sciences1, University of Melbourne2, Peking University3, Imperial College London4, King's College London5, The Turing Institute6, University of Cambridge7, Wuhan University8, Fourth Military Medical University9, Xinxiang Medical University10, Guangzhou Medical University11, Shanxi University12, Kunming Medical University13, McGovern Institute for Brain Research14
TL;DR: A new cross-validated neuroimaging biomarker that reflects striatal dysfunctioning can be used to distinguish patients with schizophrenia from healthy controls, and is associated with treatment response to antipsychotics.
Abstract: Mounting evidence suggests that function and connectivity of the striatum is disrupted in schizophrenia1–5. We have developed a new hypothesis-driven neuroimaging biomarker for schizophrenia identification, prognosis and subtyping based on functional striatal abnormalities (FSA). FSA scores provide a personalized index of striatal dysfunction, ranging from normal to highly pathological. Using inter-site cross-validation on functional magnetic resonance images acquired from seven independent scanners (n = 1,100), FSA distinguished individuals with schizophrenia from healthy controls with an accuracy exceeding 80% (sensitivity, 79.3%; specificity, 81.5%). In two longitudinal cohorts, inter-individual variation in baseline FSA scores was significantly associated with antipsychotic treatment response. FSA revealed a spectrum of severity in striatal dysfunction across neuropsychiatric disorders, where dysfunction was most severe in schizophrenia, milder in bipolar disorder, and indistinguishable from healthy individuals in depression, obsessive-compulsive disorder and attention-deficit hyperactivity disorder. Loci of striatal hyperactivity recapitulated the spatial distribution of dopaminergic function and the expression profiles of polygenic risk for schizophrenia. In conclusion, we have developed a new biomarker to index striatal dysfunction and established its utility in predicting antipsychotic treatment response, clinical stratification and elucidating striatal dysfunction in neuropsychiatric disorders. A new cross-validated neuroimaging biomarker that reflects striatal dysfunctioning can be used to distinguish patients with schizophrenia from healthy controls, and is associated with treatment response to antipsychotics.
133 citations
TL;DR: In this article, a series of Pt-WO3 catalysts with outstanding HER performance and low Pt contents were successfully prepared by a simple method, which emphasized the importance of tracking the catalyst structure dynamic evolution and provided a deep insight into the electron/hydrogen transfer process for electrocatalytic HER.
126 citations
TL;DR: A novel Na superionic conductor (NASICON)-type Na4 MnCr(PO4 )3 is developed as a high-energy cathode for SIBs, combining density functional theory (DFT) calculations with the galvanostatic intermittent titration technique to offer a new insight into the design of multielectron-reaction cathode materials for S IBs.
Abstract: Sodium-ion batteries (SIBs) have attracted incremental attention as a promising candidate for grid-scale energy-storage applications. To meet practical requirements, searching for new cathode materials with high energy density is of great importance. Herein, a novel Na superionic conductor (NASICON)-type Na4 MnCr(PO4 )3 is developed as a high-energy cathode for SIBs. The Na4 MnCr(PO4 )3 nanoparticles homogeneously embedded in a carbon matrix can present an extraordinary reversible capacity of 160.5 mA h g-1 with three-electron reaction at ≈3.53 V during the Na+ extraction/insertion process, realizing an unprecedentedly high energy density of 566.5 Wh kg-1 in the phosphate cathodes for SIBs. It is intriguing to reveal the underlying mechanism of the unique Mn2+ /Mn3+ , Mn3+ /Mn4+ , and Cr3+ /Cr4+ redox couples via X-ray absorption near-edge structure spectroscopy. The whole electrochemical reaction undergoes highly reversible single-phase and biphasic transitions with a moderate volume change of 7.7% through in situ X-ray diffraction and ex situ high-energy synchrotron X-ray diffraction. Combining density functional theory (DFT) calculations with the galvanostatic intermittent titration technique, the superior performance is ascribed to the low ionic-migration energy barrier and desirable Na-ion diffusion kinetics. The present work can offer a new insight into the design of multielectron-reaction cathode materials for SIBs.
TL;DR: The authors' results showed that young and mild COVID-19 patients seem to be RP patients after discharge, who show no obviously clinical symptoms and disease progression upon re-admission, suggesting the carrier status of virus possibly existed in patients recovered from CO VID-19.
Abstract: Summary Background It has been reported that several cases recovered from COVID-19 tested positive for SARS-CoV-2 after discharge (re-detectable positive, RP), however the clinical characteristics, significance and potential cause of RP patients remained elusive. Methods A total of 262 COVID-19 patients were discharged from January 23 to February 25, 2020, and were enrolled for analysis of their clinical parameters. The RP and non-RP (NRP) patients were grouped according to the disease severity during their hospitalization period. The clinical characterization at re-admission to the hospital was analyzed. SARS-CoV-2 RNA and plasma antibody levels were detected using high-sensitive detection methods. Findings Up to March 10, 2020, all of patients were followed up for at least 14 days, and 38/262 of RP patients (14.5%) were present. The RP patients were characterized by being less than 14-years old and having mild and moderate conditions as compared to NRP patients, while no severe patients became RP. Retrospectively, the RP patients displayed fewer symptoms, more sustained remission of CT imaging and earlier RNA negative-conversion but similar plasma antibody levels during their hospitalization period as compared to those NRP patients. When re-admitted to the hospital, these RP patients showed no obvious clinical symptoms or disease progression indicated by normal or improving CT imaging and inflammatory cytokine levels. All 21 close contacts of RP patients were tested negative for SARS-CoV-2 RNA, and no suspicious clinical symptoms were reported. However, 18/24 of RNA-negative samples detected by the commercial kit were tested to be positive for virus RNA using a hyper-sensitive method, suggesting the carrier status of virus possibly existed in patients recovered from COVID-19. Interpretation Our results showed that young and mild COVID-19 patients seem to be RP patients after discharge, who show no obviously clinical symptoms and disease progression upon re-admission. More sensitive RNA detection methods are required to monitor these patients during follow-up. Our findings provide empirical information and evidence for the effective management of COVID-19 patients during their convalescent phase.
TL;DR: This work paves the way to construct stable Na anode by hydroxylated MXene materials using h-Ti 3 C 2 /CNTs/Na anode as a scaffold for dendrite-free Na metal electrode.
Abstract: Sodium metal is a promising anode, but uneven Na deposition with a dendrite growth seriously impedes its application. Herein, a fibrous hydroxylated MXene/carbon nanotubes (h-Ti3 C2 /CNTs) composite is designed as a scaffold for dendrite-free Na metal electrodes. This composite displays fast Na+ /electron transport kinetics and good thermal conductivity and mechanical properties. The h-Ti3 C2 contains abundant sodiophilic functional groups, which play a significant role in inducing homogeneous nucleation of Na. Meanwhile, CNTs provide high tensile strength and ease of film-forming. As a result, h-Ti3 C2 /CNTs exhibit a high average Coulombic efficiency of 99.2 % and no dendrite after 1000 cycles. The h-Ti3 C2 /CNTs/Na based symmetric cells show a long lifespan over 4000 h at 1.0 mA cm-2 with a capacity of 1.0 mAh cm-2 . Furthermore, Na-O2 batteries with a h-Ti3 C2 /CNTs/Na anode exhibit a low potential gap of 0.11 V after an initial 70 cycles.
TL;DR: It is reported that orthorhombic vanadium oxides (V2O5) supports highly reversible proton intercalation/de-intercalation reactions in aqueous media, enabling aluminum electrochemical cells with extended cycle life, and it is shown that cathode coatings composed of cation selective membranes provide a straightforward method for enhancing cathode reversibility by preventing anion cross-over in aQueous electrolytes.
Abstract: Understanding cation (H+ , Li+ , Na+ , Al3+ , etc.) intercalation/de-intercalation chemistry in transition metal compounds is crucial for the design of cathode materials in aqueous electrochemical cells. Here we report that orthorhombic vanadium oxides (V2 O5 ) supports highly reversible proton intercalation/de-intercalation reactions in aqueous media, enabling aluminum electrochemical cells with extended cycle life. Empirical analyses using vibrational and x-ray spectroscopy are complemented with theoretical analysis of the electrostatic potential to establish how and why protons intercalate in V2 O5 in aqueous media. We show further that cathode coatings composed of cation selective membranes provide a straightforward method for enhancing cathode reversibility by preventing anion cross-over in aqueous electrolytes. Our work sheds light on the design of cation transport requirements for high-energy reversible cathodes in aqueous electrochemical cells.
TL;DR: The detailed analysis of high-resolution transmission electron microscopy and in-situ field Raman spectra clearly discloses the existence and rapid response feature of anti-polar nanoregions, and the resulting high driving field for the antiferroelectric to ferroelectric phase transition, laying a solid foundation for the achievement of desirable energy-storage characteristics.
Abstract: The development of environmentally friendly energy storage dielectrics with high energy storage density has attracted increasing attention in power electronics. The combination of antiferroelectric ceramics with relaxor characteristics proves to be an efficient way to greatly improve energy storage properties. In this work, a novel (Na1-x/2Lax/2)(Nb1-xTix)O3 lead-free bulk ceramic exhibits excellent energy storage properties of a giant recoverable energy storage density Wrec ≈ 6.5 J/cm3, a relatively high efficiency η ≈ 66%, and an ultrafast discharge speed t0.9 ≈ 50 ns at x = 0.18, showing outstanding potential for pulsed power capacitors. The Rietveld structural refinement and Raman spectra suggest a relaxor antiferroelectric orthorhombic R phase at room temperature as x > 0.16. Obviously enhanced breakdown strength can be ascribed to ultrafine grains of ∼0.21 μm and largely improved resistivity after BaCu(B2O5) doping. The detailed analysis of high-resolution transmission electron microscopy and in situ field Raman spectra clearly discloses the existence and rapid response feature of antipolar nanoregions and the resulting high driving field (∼30 kV/mm) for the antiferroelectric-to-ferroelectric phase transition, laying a solid foundation for the achievement of desirable energy storage characteristics. These results would provide a reliable strategy and a good understanding for designing new energy storage capacitor dielectrics.
TL;DR: In this paper, a 3D porous poly(3,4−ethylenedioxythiophene)/polystyrenesulfonate (PEDOT/PSS) electrode is integrated into a wearable thermoelectrochemical cell for harvesting human body heat.
Abstract: Thermoelectrochemical cells (thermocells) designed for harvesting human body heat can provide constant power output for wearable electronics, supplementing state‐of‐the‐art flexible power storage and conversion solutions. However, a systematic investigation into the optimization of wearable thermocells is lacking, especially with regard to device design, n‐type electrolytes, and electrode/electrolyte integration. Here, a n‐type gel electrolyte: polyvinyl alcohol‐FeCl2/3 with outstanding flexibility and elasticity and exceptional electrolyte/electrode integration into a 3D porous poly(3,4‐ethylenedioxythiophene)/polystyrenesulfonate (PEDOT/PSS) electrode, is produced via an in situ chemical crosslinking method. The integrated n‐type cell shows excellent seebeck coefficients (0.85 mV K−1) and output current density (1.74 A m−2 K−1) that are comparable with an optimized p‐type cell consisting of a carboxymethylcellulose‐K3/4Fe(CN)6 electrolyte with a 3D PEDOT/PSS‐edge functionalized graphene/carbon nanotube electrode (−1.22 mV K−1 and 1.85 A m−2 K−1). The equivalent performance of the n‐type and p‐type cells enables the effective series connection of up to 18 pairs of p–n cells that combines to give an output voltage of 0.34 V (∆T = 10 K). This in‐series device is fabricated into a proof‐of‐concept watch strap, which can harvest body heat, charge supercapacitor (up to 470 mF) as well as illuminate a green light emitting diode, demonstrating the practical applications.
TL;DR: The venetoclax-cobimetinib combination reduced leukemia burden in xenograft models using genetically engineered OCI-AML3 and MOLM13 cells and provided a rationale for combinatorial blockade of MEK and BCL2 pathways in AML.
Abstract: The pathogenesis of acute myeloid leukemia (AML) involves serial acquisition of mutations controlling several cellular processes, requiring combination therapies affecting key downstream survival nodes in order to treat the disease effectively. The BCL2 selective inhibitor venetoclax has potent anti-leukemia efficacy; however, resistance can occur due to its inability to inhibit MCL1, which is stabilized by the MAPK pathway. In this study, we aimed to determine the anti-leukemia efficacy of concomitant targeting of the BCL2 and MAPK pathways by venetoclax and the MEK1/2 inhibitor cobimetinib, respectively. The combination demonstrated synergy in seven of 11 AML cell lines, including those resistant to single agents, and showed growth-inhibitory activity in over 60% of primary samples from patients with diverse genetic alterations. The combination markedly impaired leukemia progenitor functions, while maintaining normal progenitors. Mass cytometry data revealed that BCL2 protein is enriched in leukemia stem/progenitor cells, primarily in venetoclax-sensitive samples, and that cobimetinib suppressed cytokine-induced pERK and pS6 signaling pathways. Through proteomic profiling studies, we identified several pathways inhibited downstream of MAPK that contribute to the synergy of the combination. In OCI-AML3 cells, the combination downregulated MCL1 protein levels and disrupted both BCL2:BIM and MCL1:BIM complexes, releasing BIM to induce cell death. RNA sequencing identified several enriched pathways, including MYC, mTORC1, and p53 in cells sensitive to the drug combination. In vivo, the venetoclax-cobimetinib combination reduced leukemia burden in xenograft models using genetically engineered OCI-AML3 and MOLM13 cells. Our data thus provide a rationale for combinatorial blockade of MEK and BCL2 pathways in AML.
TL;DR: The present concept of "Average Atomic Volume" can be a simple parameter to explore new NTE compounds especially in those open-framework materials.
Abstract: Exploring isotropic negative thermal expansion (NTE) compounds is interesting, but remains challenging. Here, a new concept of "average atomic volume" is proposed to find new NTE open-framework materials. According to this guidance, two NTE compounds, AgB(CN)4 and CuB(CN)4, have been discovered, of which AgB(CN)4 exhibits a large NTE over a wide temperature range (αv = -40 × 10-6 K-1, 100-600 K). The analysis by extended X-ray absorption fine structure spectroscopy and first-principles calculation indicate that (i) the NTE driving force comes from the transverse vibrations of bridge chain atoms of C and N, corresponding to the low-frequency phonon modes; and (ii) the same transverse vibration direction of C and N atoms is a key factor for the occurrence of strong NTE in AgB(CN)4. The present concept of "average atomic volume" can be a simple parameter to explore new NTE compounds especially in those open-framework materials.
TL;DR: A dual‐strategy is developed to boost the Na‐storage performance of the Fe/Mn‐based layered oxide cathode by copper (Cu) doping and nanoengineering, which symbolizes a step forward in the development of Fe-based layered oxides as high‐performance cathodes for SIBs.
Abstract: Iron/manganese-based layered transition metal oxides have risen to prominence as prospective cathodes for sodium-ion batteries (SIBs) owing to their abundant resources and high theoretical specific capacities, yet they still suffer from rapid capacity fading. Herein, a dual-strategy is developed to boost the Na-storage performance of the Fe/Mn-based layered oxide cathode by copper (Cu) doping and nanoengineering. The P2-Na0.76Cu0.22Fe0.30Mn0.48O2 cathode material synthesized by electrospinning exhibits the pearl necklace-like hierarchical nanostructures assembled by nanograins with sizes of 50-150 nm. The synergistic effects of Cu doping and nanotechnology enable high Na+ coefficients and low ionic migration energy barrier, as well as highly reversible structure evolution and Cu/Fe/Mn valence variation upon repeated sodium insertion/extraction; thus, the P2-Na0.76Cu0.22Fe0.30Mn0.48O2 nano-necklaces yield fabulous rate capability (125.4 mA h g-1 at 0.1 C with 56.5 mA h g-1 at 20 C) and excellent cyclic stability (≈79% capacity retention after 300 cycles). Additionally, a promising energy density of 177.4 Wh kg-1 is demonstrated in a prototype soft-package Na-ion full battery constructed by the tailored nano-necklaces cathode and hard carbon anode. This work symbolizes a step forward in the development of Fe/Mn-based layered oxides as high-performance cathodes for SIBs.
TL;DR: H-BN nanosheets is reported as a multifunctional support for constructing efficient electrocatalysts for the oxygen reduction reaction (ORR) because the strong interaction between h-BN and Pd downshifts the Pd d-band center, and hence optimizes the affinity with the reaction intermediates.
Abstract: Developing heterostructures with well-defined interfaces is attracting ever-increasing interest toward the development of advanced electrocatalysts. Herein, hexagonal boron nitride (h-BN) nanosheets are reported as a multifunctional support for constructing efficient electrocatalysts for the oxygen reduction reaction (ORR). h-BN/Pd heterostructured electrocatalysts with decent activity and long-term durability are designed and synthesized by confining Pd nanoparticles (NPs) on ultrathin h-BN nanosheets. The robust h-BN serves as a durable platform to maintain the structural integrity of the heterostructured catalysts. Both experimental findings and theoretical calculations reveal that the strong interaction between h-BN and Pd downshifts the Pd d-band center and hence optimizes the affinity with the reaction intermediates. Meanwhile, h-BN also endows the heterostructured catalysts with superhydrophobic surfaces, promoting the diffusion kinetics of O2. These findings open a new avenue for the rational design and development of heterostructured catalysts by interface engineering toward electrocatalysis applications.
TL;DR: This study reveals that the abundant oxygenated groups for complexing metal ions and the rich defective sites for incorporating nitrogen are essential to realize the synthesis of SACs, and the carbon nanotube supported Ni Sacs exhibit high electrocatalytic activity for CO2 reduction with nearly 100% CO selectivity.
Abstract: A general graphene quantum dot-tethering design strategy to synthesize single-atom catalysts (SACs) is presented. The strategy is applicable to different metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) and supports (0D carbon nanosphere, 1D carbon nanotube, 2D graphene nanosheet, and 3D graphite foam) with the metal loading of 3.0-4.5 wt %. The direct transmission electron microscopy imaging and X-ray absorption spectra analyses confirm the atomic dispersed metal in carbon supports. Our study reveals that the abundant oxygenated groups for complexing metal ions and the rich defective sites for incorporating nitrogen are essential to realize the synthesis of SACs. Furthermore, the carbon nanotube supported Ni SACs exhibits high electrocatalytic activity for CO2 reduction with nearly 100 % CO selectivity. This universal strategy is expected to open up new research avenues to produce SACs for diverse electrocatalytic applications.
TL;DR: A dynamic intelligent Cu (DICu) current collector with granular pile structure that dynamically accommodates the volume change by changing the packing density of the assembled particles is reported.
Abstract: Three-dimensional (3D) current collectors have shown great potential in realizing dendrite-free lithium (Li) metal anodes. However, the rigid 3D current collectors could not simultaneously suppress Li dendrite growth and allow Li plating/stripping under high capacities and large current densities. Here, we report a dynamic intelligent Cu (DICu) current collector that dynamically accommodates the volume change by changing the packing density of the assembled particles. The Li/DICu electrode achieves a high Coulombic efficiency of 99.6% after 800 cycles. The symmetrical cell shows exceptional cycling stability under the high current density of 10 mA cm-2. Notably, when assembled in full-cell batteries, the Li/DICu|LiFePO4 battery maintains a specific capacity of 139.5 mAh g-1 at 1 C for 500 cycles, and the Li/DICu|S battery delivers a specific capacity of 804 mAh g-1 after 500 cycles at 0.5 C, corresponding to the best performance among Li metal batteries with Cu-based current collectors to date.
TL;DR: In this paper, the authors describe the synthesis and application of an organic three-dimensional cyclic oligomer, calix[6]quinone (C6Q), as a high capacity cathode material for rechargeable lithium-ion batteries.
TL;DR: It is found that Succinivibrio and Corynebacterium were associated with the severity of symptoms for the first time, which may provide some new biomarkers for the diagnosis of SZ.
Abstract: Background The gut microbiome and microbiome-gut-brain (MGB) axis have been receiving increasing attention for their role in the regulation of mental behavior and possible biological basis of psychiatric disorders. With the advance of next-generation sequencing technology, characterization of the gut microbiota in schizophrenia (SZ) patients can provide rich clues for the diagnosis and prevention of SZ. Methods In this study, we compared the differences in the fecal microbiota between 82 SZ patients and 80 demographically matched normal controls (NCs) by 16S rRNA sequencing and analyzed the correlations between altered gut microbiota and symptom severity. Results The alpha diversity showed no significant differences between the NC and SZ groups, but the beta diversity revealed significant community-level separation in microbiome composition between the two groups (pseudo-F =3.337, p < 0.001, uncorrected). At the phylum level, relatively more Actinobacteria and less Firmicutes (p < 0.05, FDR corrected) were found in the SZ group. At the genus level, the relative abundances of Collinsella, Lactobacillus, Succinivibrio, Mogibacterium, Corynebacterium, undefined Ruminococcus and undefined Eubacterium were significantly increased, whereas the abundances of Adlercreutzia, Anaerostipes, Ruminococcus and Faecalibacterium were decreased in the SZ group compared to the NC group (p < 0.05, FDR corrected). We performed PICRUSt analysis and found that several metabolic pathways differed significantly between the two groups, including the Polyketide sugar unit biosynthesis, Valine, Leucine and Isoleucine biosynthesis, Pantothenate and CoA biosynthesis, C5-Branched dibasic acid metabolism, Phenylpropanoid biosynthesis, Ascorbate and aldarate metabolism, Nucleotide metabolism and Propanoate metabolism pathways (p < 0.05, FDR corrected). Among the SZ group, the abundance of Succinivibrio was positively correlated with the total Positive and Negative Syndrome Scale (PANSS) scores (r = 0.24, p < 0.05, uncorrected) as well as the general PANSS scores (r = 0.22, p < 0.05, uncorrected); Corynebacterium was negatively related to the negative scores of PANSS (r = 0.22, p < 0.05, uncorrected). Conclusions Our findings provided evidence of altered gut microbial composition in SZ group. In addition, we found that Succinvibrio and Corynebacterium were associated with the severity of symptoms for the first time, which may provide some new biomarkers for the diagnosis of SZ.
TL;DR: Due to different configurations and requirements between LIBs and RFBs, the similarities and differences for choosing suitable electrolytes are discussed.
Abstract: Electrolyte chemistry is critical for any energy-storage device. Low-cost and sustainable rechargeable batteries based on organic redox-active materials are of great interest to tackle resource and performance limitations of current batteries with metal-based active materials. Organic active materials can be used not only as solid electrodes in the classic lithium-ion battery (LIB) setup, but also as redox fluids in redox-flow batteries (RFBs). Accordingly, they have suitability for mobile and stationary applications, respectively. Herein, different types of electrolytes, recent advances for designing better performing electrolytes, and remaining scientific challenges are discussed and summarized. Due to different configurations and requirements between LIBs and RFBs, the similarities and differences for choosing suitable electrolytes are discussed. Both general and specific strategies for promoting the utilization of organic active materials are covered.
TL;DR: In this article, the effect of various TiC content on the constituent phases, microstructure, chemical composition, and grain orientation of the HEA coatings were investigated by X-ray diffraction, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron backscattered diffraction (EBSD), respectively.
TL;DR: CDK9 inhibitor plus venetoclax combination was well tolerated in vivo and demonstrated efficacy superior to either agent alone in mouse models of lymphoma and AML, indicating that CDK9 inhibitors could be highly efficacious in tumors that depend on MCL-1 for survival or when used in combination with venetclax in malignancies dependent on BCL-2.
Abstract: MCL-1 is one of the most frequently amplified genes in cancer, facilitating tumor initiation and maintenance and enabling resistance to anti-tumorigenic agents including the BCL-2 selective inhibitor venetoclax. The expression of MCL-1 is maintained via P-TEFb-mediated transcription, where the kinase CDK9 is a critical component. Consequently, we developed a series of potent small-molecule inhibitors of CDK9, exemplified by the orally active A-1592668, with CDK selectivity profiles that are distinct from related molecules that have been extensively studied clinically. Short-term treatment with A-1592668 rapidly downregulates RNA pol-II (Ser 2) phosphorylation resulting in the loss of MCL-1 protein and apoptosis in MCL-1-dependent hematologic tumor cell lines. This cell death could be attenuated by either inhibiting caspases or overexpressing BCL-2 protein. Synergistic cell killing was also observed between A-1592668 or the related analog A-1467729, and venetoclax in a number of hematologic cell lines and primary NHL patient samples. Importantly, the CDK9 inhibitor plus venetoclax combination was well tolerated in vivo and demonstrated efficacy superior to either agent alone in mouse models of lymphoma and AML. These data indicate that CDK9 inhibitors could be highly efficacious in tumors that depend on MCL-1 for survival or when used in combination with venetoclax in malignancies dependent on MCL-1 and BCL-2.
TL;DR: In this article, a novel full cell is assembled by phenazine anode, Na 0.44MnO2 cathode and 10 M NaOH electrolyte to further explore the electrochemical performance of phenazine.
Abstract: Aqueous rechargeable batteries are a possible strategy for large-scale energy storage systems. However, limited choices of anode materials restrict their further application. Here we report phenazine (PNZ) as stable anode materials in different alkali-ion (Li+, Na+, K+) electrolyte. A novel full cell is assembled by phenazine anode, Na0.44MnO2 cathode and 10 M NaOH electrolyte to further explore the electrochemical performance of phenazine anode. This battery is able to achieve high capacity (176.7 mAh·g−1 at 4 C (1.2·Ag−1)), ultralong cycling life (capacity retention of 80% after 13,000 cycles at 4 C), and excellent rate capacity (92 mAh·g−1 at 100 C (30 A·g−1)). The reaction mechanism of PNZ during charge—discharge process is demonstrated by in situ Raman spectroscopy, in situ Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Furthermore, the system is able to successfully operate at wide temperature range from −20 to 70 °C and achieves remarkable electrochemical performance.