5S-Heudelotinone alleviates experimental colitis by shaping the immune system and enhancing the intestinal barrier in a gut microbiota-dependent manner

Aberrant changes in the gut microbiota are implicated in many diseases,including inflammatory bowel disease(IBD).Gut microbes produce diverse metabolites that can shape the immune system and impact the intestinal barrier integrity,indicating that microbe-mediated modulation may be a promising strategy for preventing and treating IBD.Although fecal microbiota transplantation and probiotic supplementation are well-established IBD therapies,novel chemical agents that are safe and exert strong effects on the gut microbiota are urgently needed.Herein,we report the total synthesis of heudelotinone and the discovery of 5S-heudelotinone(an enantiomer)as a potent agent against experimental colitis that acts by modulating the gut microbiota.5S-Heudelotinone alters the diversity and composition of the gut microbiota and increases the concentration of short-chain fatty acids(SCFAs);thus,it regulates the intestinal immune system by reducing proinflammatory immune cell numbers,and maintains intestinal mucosal integrity by modulating tight junctions(TJs).Moreover,5S-heudelotinone(2)ameliorates colitis-associated colorectal cancer(CAC)in an azoxymethane(AOM)/dextran sulfate sodium(DSS)-induced in situ carcinoma model.Together,these findings reveal the potential of a novel natural product,namely,5S-heudelotinone,to control intestinal inflammation and highlight that this product is a safe and effective candidate for the treatment of IBD and CAC.

Volume-complementary bipolar layered oxide enables stable symmetric sodium-ion batteries

The commercialization of sodium-ion batteries is based on developing low-cost,highly stable,and safe cathode and anode electrodes.However,the promising hard carbon anode and layered oxide cathode suffer from low sodium-embedded potential near 0.1 V and severe phase transitions,which cause safe problem and short lifespan,respectively.Herein,we design a low-strain bipolar P2-Na_(0.7)Ni_(0.25)Fe_(0.2)Ti_(0.55)O_(2) to solve the mentioned obstacles,whereas(Ni,Fe)and Ti provide charge compensation when it is used as cathode and anode,respectively.It is revealed that the bipolar layered oxide undergoes solid-solution reaction when used as cathode or anode,and exhibits volume-complementary feature in a sodium-ion full-cell,as identified by in-situ X-ray diffraction.Remarkably,the safe symmetric sodium-ion full-cell exhibits excellent cyclic stability with 91.7%capacity retention after 200 cycles.This work will provide a new horizon for designing safe and stable sodium-ion batteries.

Computational study of transition metal single-atom catalysts supported on nitrogenated carbon nanotubes for electrocatalytic nitrogen reduction

Developing efficient and stable catalysts for the electrocatalytic N_(2)reduction reaction(NRR)shows promise in nitrogen fixation.Here,we proposed active and stable single-atom catalysts(SACs)toward NRR,where transition metals are anchored on nitrogenated carbon nanotubes(NCNTs).Among the screened nine common transition metals(Ti,V,Cr,Mn,Fe,Mo,Ru,Rh,and Ag)on(4,4)NCNTs,we found Mo-NCNT possesses the most excellent NRR catalytic activity and selectivity with a low overpotential of 0.29 V.Then,the NRR performance of Mo-NCNT was further engineered by controlling the nanotube diameter,where the lowest overpotential is 0.18 V at a diameter of 9.6Å.In addition,we found a linear scaling relation between*NNH and*NH_(2)on the studied catalysts with the exception of(2,2)and(3,3)Mo-NCNTs,owing to their extremely unstable structures.We attribute the outstanding NRR performance of Mo-NCNT to the moderate adsorption of N_(2)due to the slightly low d-band center of Mo,and the charge donating and accepting capacity of NCNTs.This work has provided a deeper insight into designing highefficiency and stable NRR SACs supported by NCNTs.

Efficiently coupled glucose oxidation for high-value D-glucaric acid with ultradurable hydrogen via Mn(III)in acidic solution

The electrooxidation of the alcohol and aldehyde molecules instead of water coupled with H2 production has been proven to be effective for producing high-value fine chemicals under alkaline conditions.It is also noteworthy that under acidic conditions,the stability of non-noble metal water oxidation catalysts remains a great challenge due to the lattice oxygen mechanism.Hence,we coupled the biomass-derived glucose oxidation for high-value D-glucaric acid(GRA)with ultra-durable hydrogen in acid solution over a Yb-MnO_(2)catalyst.The Mn^(3+)regulated by Yb atoms doped in MnO_(2)can effectively optimize the adsorption and desorption processes of the alcohol and aldehyde group and improve the intrinsic activity but cannot for H2O.The catalyst exhibited extremely high activity and stability after 50 h for glucose oxidation,inhibiting the lattice oxygen process and MnO4−formation,while the activity was quickly lost within 0.5 h for water oxidation.Density functional theory(DFT)calculations further demonstrated that glucose oxidation reaction proceeds preferentially due to the oxidation of aldehyde group with lower adsorption-free energy(−0.4 eV)than water(ΔG>0 eV),avoiding the lattice oxygen mechanism.This work suggests that biomass-derived glucose oxidation not only provides a cost-effective approach for high-value chemicals,but also shows an extremely potential as an alternative to acidic oxygen evolution reaction(OER)for ultradurable H2 production.

Highly emissive tribenzotriquinacene-based double-rimed nanocube

The study of discrete nanosized cages has gone a long way to seek aesthetically appealing structures and to carry out functional applications.Although the construction of supramolecular cages via a bottom-up self-assembly process has been well developed,the sophisticated synthesis still remains a challenge.Here we report the design and assembly of a giant double-rimed nanocube Zn_(24)LH_(8),built with 8 tribenzotriquinacene as six-connected vertices and 24<tpy-Zn^(2+)-tpy>(tpy=terpyridine)connectivities serving as the edges.From the single-crystal structure of tribenzotriquinacene-based ligand LH,the bowl-shaped ligand defines a suitable rigid platform for the spatially well-defined attachment of three sets of parallel vertices,which promotes the quantitative formation of the desired three-dimensional(3D)double-rimed cubic architectures.The formed nanocube Zn_(24)LH_(8)possesses molecular weight up to 25.6 kDa and side length 5.3 nm.Remarkably,the Zn_(24)LH_(8)exhibits strong cyan light emission with high luminescence quantum yields in solution and in the solid state based on the inherent cage-confinement induced emission enhancement.By adding orange-emissive Rhodamine B,emission tuning experiments were achieved including white light emission.This work presents a new system for the imitation of complex assemblies and provides a promising candidate for emissive materials.

Corrosion formation and phase transformation of nickel-iron hydroxide nanosheets array for efficient water oxidation

Designing earth-abundant electrocatalysts with high performance towards water oxidation is highly decisive for the sustainable energy technologies. This study develops a facile natural corrosion approach to fabricate nickel-iron hydroxides for water oxidation. The resulted electrode demonstrates an outstanding activity and stability with an overpotential of 275 mV to deliver 10 mA·cm^(−2). Experimental and theoretical results suggest the corrosion-induced formation of hydroxides and their transformation to oxyhydroxides would account for this excellent performance. This work not only provides an interesting corrosion approach for the fabrication of excellent water oxidation electrode, but also bridges traditional corrosion engineering and novel materials fabrication, which would offer some insights in the innovative principles for nanomaterials and energy technologies.

Low‐dimensional material supported single‐atom catalysts for electrochemical CO_(2) reduction

Converting CO_(2) emissions to valuable carbonaceous chemicals/fuels under mild conditions provides a sustainable way to maintain carbon balance and alleviate the energy shortage.Low‐dimensional material(LDM)supported single‐atom catalysts(SACs)have been attracted significant attention for electrochemical CO_(2) reduction reaction(ECR)in recent years.This is mainly because integrating the single‐atoms and LDMs can inherit the advantages of themselves and the synergy effects between them are potential to enhance the ECR performance.In this review,we summarized the strategies for synthesizing LDM supported SACs for ECR,and different LDM supported SACs for ECR have been briefly introduced.Moreover,some optimization strategies for LDM supported SACs towards CO_(2) electroreduction are highlighted.At the end of this review,the perspectives and challenges of LDM supported SACs for ECR are provided.

超低铂合金与纳米碳结构直接集成的高效氧还原催化剂的设计

开发高效的铂(Pt)基电催化剂对于燃料电池的发展具有极其重要的意义.本文报道了一种氮掺杂纳米碳结构包覆的超低Pt合金集成电催化剂并用于燃料电池氧还原反应.该Pt基催化剂复合材料在0.9 V vs.RHE的电位下展现出3.46 A mg^(-1)_(Pt)质量活性,并且在10000圈循环后几乎没有衰减.单电池测试结果表明,其Pt利用率高达10.22 W mg^(-1)_(Pt)阴极,并具有30000圈循环的优异耐久性.实验和理论研究表明,将Co/Ni掺入Pt晶格可产生具有最佳Pt-O结合能的高应变Pt结构,这可显著加快反应动力学.氮掺杂纳米碳结构和活性Pt组分产生的协同催化作用是提高催化活性的主要原因,同时增强的金属-载体相互作用和优化的亲水性能可促进传质过程和水管理.这项工作可为燃料电池及其他领域的低Pt集成电催化剂的设计提供重要见解.