Analysis of Genome Architecture during SCNT Reveals a Role of Cohesin in Impeding Minor ZGA.

Somatic cell nuclear transfer (SCNT) can reprogram a somatic nucleus to a totipotent state. However, the re-organization of 3D chromatin structure in this process remains poorly understood. Using low-input Hi-C, we revealed that, during SCNT, the transferred nucleus first enters a mitotic-like state (premature chromatin condensation). Unlike fertilized embryos, SCNT embryos show stronger topologically associating domains (TADs) at the 1-cell stage. TADs become weaker at the 2-cell stage, followed by gradual consolidation. Compartments A/B are markedly weak in 1-cell SCNT embryos and become increasingly strengthened afterward. By the 8-cell stage, somatic chromatin architecture is largely reset to embryonic patterns. Unexpectedly, we found cohesin represses minor zygotic genome activation (ZGA) genes (2-cell-specific genes) in pluripotent and differentiated cells, and pre-depleting cohesin in donor cells facilitates minor ZGA and SCNT. These data reveal multi-step reprogramming of 3D chromatin architecture during SCNT and support dual roles of cohesin in TAD formation and minor ZGA repression.

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)-H and C(sp3)-H bonds.

Organochalcogen compounds are prevalent in numerous natural products, pharmaceuticals, agrochemicals, polymers, biological molecules and synthetic intermediates. Direct chalcogenation of C-H bonds has evolved as a step- and atom-economical method for the synthesis of chalcogen-bearing compounds. Nevertheless, direct C-H chalcogenation severely lags behind C-C, C-N and C-O bond formations. Moreover, compared with the C-H monochalcogenation, reports of selective mono-/dichalcogenation and exclusive dichalcogenation of C-H bonds are relatively scarce. The past decade has witnessed significant advancements in selective mono-/dichalcogenation and exclusive dichalcogenation of various C(sp2)-H and C(sp3)-H bonds via transition-metal-catalyzed/mediated, photocatalytic, electrochemical or metal-free approaches. In light of the significance of both mono- and dichalcogen-containing compounds in various fields of chemical science and the critical issue of chemoselectivity in organic synthesis, the present review systematically summarizes the advances in these research fields, with a special focus on elucidating scopes and mechanistic aspects. Moreover, the synthetic limitations, applications of some of these processes, the current challenges and our own perspectives on these highly active research fields are also discussed. Based on the substrate types and C-H bonds being chalcogenated, the present review is organized into four sections: (1) transition-metal-catalyzed/mediated chelation-assisted selective C-H mono-/dichalcogenation or exclusive dichalcogenation of (hetero)arenes; (2) directing group-free selective C-H mono-/dichalcogenation or exclusive dichalcogenation of electron-rich (hetero)arenes; (3) C(sp3)-H dichalcogenation; (4) dichalcogenation of both C(sp2)-H and C(sp3)-H bonds. We believe the present review will serve as an invaluable resource for future innovations and drug discovery.

A Disturbance Compensation Control Strategy for Rotational Speed Standard Device Based on AMB System.

The rotational speed standard device that can carry loads is the key device for calibrating passive rotational speed sensors. The rotor of the passive rotational speed sensor is connected to the rotor of the standard speed device through a coupling, and the standard reference speed is provided by the standard device. Due to the rotor eccentricity, the unbalanced force of the rotor occurs, and it can not only affect the rotational speed accuracy but can also damage the mechanical bearings of the standard speed device. To solve this issue, a method for suppressing the unbalanced force of the speed standard device based on an active magnetic bearing (AMB) force compensation system is proposed. First, the overall structure of the system is briefly introduced. Then, the force feedback control system model with the AMB as the force actuator is established, and a PI controller is designed to achieve the disturbed force control. Finally, a semi-physical simulation experimental platform is built to verify the effectiveness of the proposed method. The experimental results show that the AMB force compensation system can reduce 84.4%, 81.6%, and 79.8% of the unbalanced vibration force at the frequency of 30 Hz, 90 Hz, and 150 Hz, respectively.

Nicotine exposure disrupts placental development via the Notch signaling pathway.

In brief: Normal gene expression during early embryonic development and in the placenta is crucial for a successful pregnancy. Nicotine can disrupt normal gene expression during development, leading to abnormal embryonic and placental development. Abstract: Nicotine is a common indoor air pollutant that is present in cigarette fumes. Due to its lipophilic nature, nicotine can rapidly transport through membrane barriers and spread throughout the body, which can lead to the development of diseases. However, the impact of nicotine exposure during early embryonic development on subsequent development remains elusive. In this study, we found that nicotine significantly elevated reactive oxygen species, DNA damage and cell apoptosis levels with the decrease of blastocyst formation during early embryonic development. More importantly, nicotine exposure during early embryonic development increased placental weight and disrupted placental structure. In molecular level, we also observed that nicotine exposure could specifically cause the hypermethylation of Phlda2 promoter (a maternally expressed imprinted gene associated with placental development) and reduce the mRNA expression of Phlda2. By RNA sequencing analysis, we demonstrated that nicotine exposure affected the gene expression and excessive activation of the Notch signaling pathway thereby affecting placental development. Blocking the Notch signaling pathway by DAPT treatment could recover abnormal placental weight and structure induced by nicotine exposure. Taken together, this study indicates that nicotine causes the declining quality of early embryos and leads to placental abnormalities related to over-activation of the Notch signaling pathway.

The important role of surface charge on a new mechanism of nitrogen reduction.

The electrocatalytic nitrogen reduction reaction (NRR) is a green and sustainable approach for producing ammonia. Low-cost carbon-based materials are promising catalysts for the electrochemical NRR. Among them, Cu-N4-graphene is a unique catalytic substrate. Its catalytic performance for the NRR has remained unclear as N2 can only be physisorbed on such a substrate. In this work, we focus on the influence of an electronic environment on the electrocatalytic NRR. DFT computations reveal that the NN bond can be effectively activated at a surface charge density of -1.88 × 1014 e cm-2 on Cu-N4-graphene and further the NRR proceeds via an alternating hydrogenation pathway. This work offers a new insight into the mechanism of the electrocatalytic NRR and emphasizes the importance of environmental charges in the electrocatalytic process of the NRR.

m6 A demethylase Fto regulates the TNF-α-induced inflammatory response in cementoblasts.

OBJECTIVE: Apical periodontitis is the most frequently occurring pathological lesion. Fat mass and obesity-associated protein (Fto) is the first identified RNA N6-methyladenosine demethylase. However, whether Fto regulates apical periodontitis remains unclear. This study aimed to explore the mechanisms of Fto in the tumor necrosis factor-α (TNF-α)-induced inflammatory response. MATERIALS AND METHODS: We established an apical periodontitis model. An immortalized cementoblast cell line (OCCM-30) cells were exposed to TNF-α. Fto, Il6, Mcp1, and Mmp9 expressions were assessed by qRT-PCR. We knocked down Fto using lentiviruses and detected TNF-α-induced inflammation-related gene expressions and mRNA stability. RESULTS: Mice with apical periodontitis showed downregulation of Fto expression. OCCM-30 cells exposed to TNF-α showed an upregulation of inflammation-related genes with a decrease in Fto. Furthermore, knockdown of Fto promoted the expressions of Il6, Mcp1, and Mmp9 in TNF-α-treated OCCM-30 cells as compared with negative control cells, whereas it did not affect the mRNA stability. Interestingly, Fto knockdown activated the p65, p38, and ERK1/2 pathways, and it slightly activated the JNK signaling pathway after TNF-α administration in OCCM-30 cells. CONCLUSION: A TNF-α-induced decrease in the expression of Fto might play a critical role in the inflammatory response in cementoblasts, and knockdown of Fto might upregulate the inflammatory response.

Targeted Immunoimaging of Tumor-Associated Macrophages in Orthotopic Glioblastoma by the NIR-IIb Nanoprobes.

Developing dynamic and highly sensitive methods for imaging M2-type tumor-associated macrophages (TAMs) is vital for monitoring the tumor progression and assessing the therapeutic efficacy. Here, the fabrication and application of rationally designed Er-based rare-earth nanoprobes for the targeted imaging of M2-type TAMs in glioblastoma (GBM) through the second near-infrared (NIR-II) fluorescence beyond 1500 nm is reported. The NIR-IIb fluorescence of Er-based rare-earth nanoparticles can be remarkably enhanced by optimizing their core-shell structures and the shell thickness, which allows for in vivo imaging under excitation by a 980 nm laser with the lowest power density (40 mW cm-2 ). These bright Er-based nanoparticles functionalized with M2pep polypeptide show notable targeting ability to M2-type macrophages, which has been well tested in both in vitro and in vivo experiments by their up-conversion (UC) fluorescence (540 nm) and down-shifting (DS) fluorescence (1525 nm), respectively. The targeting capability of these nanoprobes in vivo is also demonstrated by the overlap of immunofluorescence of M2-type TAMs and Arsenazo III staining of rare-earth ions in tumor tissue. It is envisioned that these nanoprobes can serve as a companion diagnostic tool to dynamically assess the progression and prognosis of GBM.

Design of the all-silicon long-wavelength infrared achromatic metalens based on deep silicon etching.

An all-silicon long-wavelength infrared (LWIR) achromatic metalens based on deep silicon etching is designed in this paper. With a fixed aperture size, the value range of the equivalent optical thickness of the non-dispersive meta-atoms constructing the achromatic metalens determines the minimum f-number. The fabrication characteristic with high aspect ratio of deep silicon etching amplifies the difference value of optical thickness between different meta-atoms by increasing the propagation distance of the propagation mode, which ensures a small f-number to obtain a better imaging resolution. A 280-µm-diameter silicon achromatic metalens with a f-number of 1 and the average focusing efficiency of 27.66% has been designed and simulated to validate the feasibility of this strategy. The simulation results show that the maximum focal length deviation percentage from the target value between the wavelength of 8.6 and 11.4 µm is 1.61%. This achromatic metalens design is expected to play a role in the field of LWIR integrated optical system.

Broadening of horizons in the synthesis of CD3-labeled molecules.

In the light of the recent potentials of deuterated molecules as pharmaceuticals or even in mechanistic understanding, efficient methods for their synthesis are continually desired. CD3-containing molecules are prominent amongst these motifs due to the parallel of the "magic methyl effect": introducing a methyl group into pharmaceuticals could positively affect biological activities. The trideuteromethyl group is bound to molecules either by C, N, O, or S atom. For a long time, the preparation methods of such labeled compounds were underestimated and involved multi-step syntheses. More recently, specific approaches dealing with the direct incorporation of the CD3 group have been developed. This Review gives an overview of the methods for the preparation of CD3-labeled molecules from conventional functional group interconversion techniques to catalytic approaches and include radical strategy. Detailed reaction mechanisms are also discussed.

Fetal growth restriction mice are more likely to exhibit depression-like behaviors due to stress-induced loss of dopaminergic neurons in the VTA.

Fetal growth restriction (FGR) is a severe perinatal complication that can increase risk for mental illness. To investigate the mechanism by which FGR mice develop mental illness in adulthood, we established the FGR mouse model and the FGR mice did not display obvious depression-like behaviors, but after environmental stress exposure, FGR mice were more likely to exhibit depression-like behaviors than control mice. Moreover, FGR mice had significantly fewer dopaminergic neurons in the ventral tegmental area but no difference in serotoninergic neurons in the dorsal raphe. RNA-seq analysis showed that the downregulated genes in the midbrain of FGR mice were associated with many mental diseases and were especially involved in the regulation of NMDA-selective glutamate receptor (NMDAR) activity. Furthermore, the NMDAR antagonist memantine can relieve the stress-induced depression-like behaviors of FGR mice. In summary, our findings provide a theoretical basis for future research and treatment of FGR-related depression.

CO2 Capture, Separation and Reduction on Boron-Doped MoS2 , MoSe2 and Heterostructures with Different Doping Densities: A Theoretical Study.

Designing high-performance materials for CO2 capture and conversion is of great significance to reduce the greenhouse effect and alleviate the energy crisis. The strategy of doping is widely used to improve activity and selectivity of the materials. However, it is unclear how the doping densities influence the materials' properties. Herein, we investigated the mechanism of CO2 capture, separation and conversion on MoS2 , MoSe2 and Janus MoSSe monolayers with different boron doping levels using density functional theory (DFT) simulations. The results indicate that CO2 , H2 and CH4 bind weakly to the monolayers without and with single-atom boron doping, rendering these materials unsuitable for CO2 capture from gas mixtures. In contrast, CO2 binds strongly to monolayers doped with diatomic boron, whereas H2 and CH4 can only form weak interactions with these surfaces. Thus, the monolayers doped with diatomic boron can efficiently capture and separate CO2 from such gas mixtures. The electronic structure analysis demonstrates that monolayers doped with diatomic doped are more prone to donating electrons to CO2 than those with single-atom boron doped, leading to activation of CO2 . The results further indicate that CO2 can be converted to CH4 on diatomic boron doped catalysts, and MoSSe is the most efficient of the surfaces studied for CO2 capture, separation and conversion. In summary, the study provides evidence for the doping density is vital to design materials with particular functions.

Pharmacokinetics and tissue distribution study of obtusifolin in rats by liquid chromatography-tandem mass spectrometry.

This paper reports the validation of an assay for obtusifolin based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its application to a preclinical pharmacokinetic study in rats. After sample preparation of plasma and tissue homogenates by protein precipitation, the analyte and internal standard (IS) were separated by a reversed-phase chromatographic system in a run time of 5.0 min and detected by negative ion electrospray ionization followed by selected reaction monitoring of the precursor-to-product ion transitions at m/z 283.0-268.1 for obtusifolin and m/z 329.0-314.1 for IS. The assay was linear in the concentration range 1.0-500 ng/ml with the LLOQ of 1.0 ng/ml. In the pharmacokinetic study of an intragastric administration of 1.3 mg/kg obtusifolin, the maximum plasma concentration of obtusifolin was 152.5 ± 62.3 ng/ml, reached at 0.39 ± 0.17 h. The AUC0-t and AUC0-∞ were 491.8 ± 256.7 and 501.7 ± 256.7 ng × h/ml, respectively, with an elimination half-life of 3.1 ± 0.7 h. Obtusifolin was rapidly distributed into tissues, with the highest distribution in the liver and less in the brain. These results will give some insights for further pharmacological investigation of obtusifolin.

Lunar Surface Fault-Tolerant Soft-Landing Performance and Experiment for a Six-Legged Movable Repetitive Lander.

The cascading launch and cooperative work of lander and rover are the pivotal methods to achieve lunar zero-distance exploration. The separated design results in a heavy system mass that requires more launching costs and a limited exploration area that is restricted to the vicinity of the immovable lander. To solve this problem, we have designed a six-legged movable repetitive lander, called "HexaMRL", which congenitally integrates the function of both the lander and rover. However, achieving a buffered landing after a failure of the integrated drive units (IDUs) in the harsh lunar environment is a great challenge. In this paper, we systematically analyze the fault-tolerant capacity of all possible landing configurations in which the number of remaining normal legs is more than two and design the landing algorithm to finish a fault-tolerant soft-landing for the stable configuration. A quasi-incentre stability optimization method is further proposed to increase the stability margin during supporting operations after landing. To verify the fault-tolerant landing performance on the moon, a series of experiments, including five-legged, four-legged and three-legged soft-landings with a vertical landing velocity of -1.9 m/s and a payload of 140 kg, are successfully carried out on a 5-DoF lunar gravity ground-testing platform. The HexaMRL with fault-tolerant landing capacity will greatly promote the development of a next-generation lunar prober.

Study on soft sensor modeling method for sign of contaminated fermentation broth in Chlortetracycline fermentation process.

During Chlortetracycline fermentation, contamination of fermentation broth by non-target bacteria is an unavoidable problem. There is no online analytical instrument to determine whether the fermentation broth has been contaminated. Only the results of manual sampling analysis can be used to determine whether the fermentation broth is contaminated. This analysis process usually takes several hours. In order to predict online whether the fermentation broth is contaminated by non-target bacteria, a soft sensor modeling method for the signs of contamination in Chlortetracycline fermentation broth was proposed in this paper. Based on recursive wavelet neural network (RWNN) and Gaussian process regression (GPR) method, the soft sensor model of online measurable parameters and total sugar content of fermentation broth was established. By deeply analyzing the correlation between the total sugar content (it is a parameter that is difficult to measure online) of fermentation broth and the signs of bacterial contamination during fermentation, a soft sensor model was established combining with the correlation between the total sugar content of fermentation broth and the symptoms of bacterial infection, and the symptoms of non-target bacterial infection of fermentation broth were predicted. Based on the field data of the fermentation process, the different signs of Chlortetracycline fermentation were predicted for the fermentation broth uninfected with non-target bacteria, infected with bacilli and infected with phages. The experimental results showed that the proposed soft sensor model could be used to predict the occurrence of contamination during Chlortetracycline fermentation. Based on the field data, the validity of the modeling method is verified. The proposed soft sensor model of signs of bacterial contamination can be used to predict the occurrence of bacterial contamination in Chlortetracycline, Penicillin and related biological fermentation processes. So that the site operators can take effective measures in time to reduce production losses to a minimum.

Robust Cobalt Catalyst for Nitrile/Alkyne [2+2+2] Cycloaddition: Synthesis of Polyarylpyridines and Their Mechanochemical Cyclodehydrogenation to Nitrogen-Containing Polyaromatics*.

The transition-metal-catalyzed [2+2+2] cycloaddition of nitriles and alkynes is an established synthetic approach to pyridines; however, these cycloadditions often rely on the use of tethered diynes or cyanoalkynes as one of the reactants. Thus, examples of efficient, fully intermolecular catalytic [2+2+2] pyridine synthesis, especially those employing unactivated nitriles and internal alkynes leading to pentasubstituted pyridines, remain scarce. Herein, we report on simple and inexpensive catalytic systems based on cobalt(II) iodide, 1,3-bis(diphenylphosphino)propane, and Zn that promote [2+2+2] cycloaddition of various nitriles and diarylacetylenes for the synthesis of a broad range of polyarylated pyridines. DFT studies support a reaction pathway involving oxidative coupling of two alkynes, insertion of the nitrile into a cobaltacyclopentadiene, and C-N reductive elimination. The resulting tetra- and pentaarylpyridines serve as precursors to hitherto unprecedented nitrogen-containing polycyclic aromatic hydrocarbons via mechanochemically assisted multifold reductive cyclodehydrogenation.

Iron-Catalyzed Radical Asymmetric Aminoazidation and Diazidation of Styrenes.

Asymmetric aminoazidation and diazidation of alkenes are straightforward strategies to build value-added chiral nitrogen-containing compounds from feedstock chemicals. They provide direct access to chiral organoazides and complement enantioselective diamination. Despite the advances in non-asymmetric reactions, asymmetric aminoazidation or diazidation based on acyclic systems has not been previously reported. Here we describe the iron-catalyzed intermolecular asymmetric aminoazidation and diazidation of styrenes. The method is practically useful and requires relatively low loading of catalyst and chiral ligand. With mild reaction conditions, the reaction can be completed on a 20 mmol scale. Studies of the mechanism suggest that the reaction proceeds via a radical pathway and involves stereocontrol of an acyclic free radical which probably takes place through a group transfer mechanism.

Size-Dependent Photothermal Conversion and Photoluminescence of Theranostic NaNdF4 Nanoparticles under Excitation of Different-Wavelength Lasers.

The narrow absorption and emission bands, long fluorescence lifetime, and excellent stability of rare earth nanoparticles (referred to as RE NPs) make them very attractive for multimodal imaging and therapy of cancer. Their narrow absorption requires the careful selection of laser wavelength to achieve the best performance, particularly for RE NPs simultaneously having photothermal and photoluminescent properties (e.g., Nd-based nanoparticles), which has not been investigated. Herein, we prepared a series of different-sized NaNdF4 nanoparticles (referred to as NNF NPs) (i.e., 4.7, 5.9, 12.8, and 15.6 nm) from ultrasmall nanoclusters and investigated their in vitro and in vivo size-dependent photothermal conversion and photoluminescence under irradiation by a 793 nm laser and an 808 nm laser, respectively. We find that all nanoparticles exhibited the better photothermal conversion performance under the irradiation of the 808 nm laser than under the 793 nm laser, of which 12.8 nm NNF NPs showed the best performance, and the temperature of their solution can be quickly increased from 30 °C to around 60 °C within 10 min under the irradiation of the 808 nm laser with a power intensity of 0.75 W/cm2. When we used the 793 nm laser to excite these NNF NPs, we found that all nanoparticles exhibited the stronger photoluminescence in the second near-infrared window (NIR-II) than under the excitation by the 808 nm laser, of which 15.6 nm NNF NPs possessed the strongest NIR-II luminescence. We then modified 12.8 nm NNF NPs with phospholipid carboxyl PEG and functionalized with RGD for actively targeted imaging of cancer. The NaNdF4@PEG@RGD nanoparticles (referred to as NNF-P-R NPs) have good biocompatibility, stability, and excellent targeting capability. The in vivo result show that 12.8 nm NNF NPs exhibited better photothermal conversion performance under the irradiation of the 808 nm laser, and stronger NIR-II fluorescence under irradiation of the 793 nm laser, which are consistent with the in vitro result. This work demonstrates the significance of selection of the proper laser wavelength for maximally taking advantage of RE nanoparticles for the diagnosis and treatment of cancer.

Novel peptide derived from IGF-2 displays anti-angiogenic activity in vitro and inhibits retinal angiogenesis in a model of oxygen-induced retinopathy.

BACKGROUND: Retinopathy of prematurity (ROP), a major cause of significant visual morbidity and blindness in preterm infants, is closely related to pathological angiogenesis. The aim of the study is to evaluate the effect of a new 12-aa peptide (named peptide CW-703) from human insulin-like growth factor-2, against angiogenesis in ROP. METHODS: In order to evaluate the inhibitory effect of CW-703 on the proliferation, migration, tube formation and apoptosis of human umbilical vein endothelial cells (ScienCell) in vitro, we used MTS assays, a modified Boyden chamber, Matrigel system and TUNEL assays. Effects in vivo were assayed using chorioallantoic membrane assays and oxygen-induced retinopathy (OIR) models in mice. We also performed eletrophysiological and histologic examinations to evaluate the possible toxicity of the peptide. Real-time PCR, ELISA and western blotting were used to elucidate the mechanism of CW-703. RESULTS: CW-703 inhibited angiogenesis in vitro by suppressing endothelial cell proliferation, migration and tube formation. CW-703 also prevented angiogenesis in chicken chorioallantoic membrane assays and OIR assays in mice. No evident functional or morphologic abnormalities in neuroretina after CW-703 injection were revealed in electrophysiological tests and histological examinations. Moreover, we elucidated that CW-703 competed for binding to IGF-1R and inhibited angiogenesis by inhibiting IGF-1R/PI3K/AKT activation and downregulating vascular endothelial growth factor expression. CONCLUSION: The novel peptide CW-703 may act as an effective inhibitor of ocular pathologic angiogenesis, especially in treating ROP.

Speed Calibration and Traceability for Train-Borne 24 GHz Continuous-Wave Doppler Radar Sensor.

The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)°, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.

Electrocatalytically Active Fe-(O-C2 )4 Single-Atom Sites for Efficient Reduction of Nitrogen to Ammonia.

Single-atom catalysts have demonstrated their superiority over other types of catalysts for various reactions. However, the reported nitrogen reduction reaction single-atom electrocatalysts for the nitrogen reduction reaction exclusively utilize metal-nitrogen or metal-carbon coordination configurations as catalytic active sites. Here, we report a Fe single-atom electrocatalyst supported on low-cost, nitrogen-free lignocellulose-derived carbon. The extended X-ray absorption fine structure spectra confirm that Fe atoms are anchored to the support via the Fe-(O-C2 )4 coordination configuration. Density functional theory calculations identify Fe-(O-C2 )4 as the active site for the nitrogen reduction reaction. An electrode consisting of the electrocatalyst loaded on carbon cloth can afford a NH3 yield rate and faradaic efficiency of 32.1 µg h-1 mgcat. -1 (5350 µg h-1 mgFe -1 ) and 29.3 %, respectively. An exceptional NH3 yield rate of 307.7 µg h-1 mgcat. -1 (51 283 µg h-1 mgFe -1 ) with a near record faradaic efficiency of 51.0 % can be achieved with the electrocatalyst immobilized on a glassy carbon electrode.