The reaction of precursors containing both nitrogen and oxygen atoms with NiII under 500 °C can generate a N/O mixing coordinated Ni‐N3O single‐atom catalyst (SAC) in which the oxygen atom can be ...gradually removed under high temperature due to the weaker Ni−O interaction, resulting in a vacancy‐defect Ni‐N3‐V SAC at Ni site under 800 °C. For the reaction of NiII with the precursor simply containing nitrogen atoms, only a no‐vacancy‐defect Ni‐N4 SAC was obtained. Experimental and DFT calculations reveal that the presence of a vacancy‐defect in Ni‐N3‐V SAC can dramatically boost the electrocatalytic activity for CO2 reduction, with extremely high CO2 reduction current density of 65 mA cm−2 and high Faradaic efficiency over 90 % at −0.9 V vs. RHE, as well as a record high turnover frequency of 1.35×105 h−1, much higher than those of Ni‐N4 SAC, and being one of the best reported electrocatalysts for CO2‐to‐CO conversion to date.
A vacancy defect was controllably constructed at the Ni site in a nickel single‐atom catalyst. It shows significantly enhanced electrocatalytic activity and selectivity for CO2‐to‐CO conversion compared with the Ni‐N4 catalyst.
The catalytic activity of metal clusters is closely related with the support; however, knowledge on the influence of the support on the catalytic activity is scarce. We demonstrate that Pt ...nanoclusters (NCs) anchored on porous TiO2 nanosheets with rich oxygen vacancies (VO‐rich Pt/TiO2) and deficient oxygen vacancies (VO‐deficient Pt/TiO2), display significantly different catalytic activity for the hydrogen evolution reaction (HER), in which VO‐rich Pt/TiO2 shows a mass activity of 45.28 A mgPt−1 at −0.1 V vs. RHE, which is 16.7 and 58.8 times higher than those of VO‐deficient Pt/TiO2 and commercial Pt/C, respectively. DFT calculations and in situ Raman spectra suggest that porous TiO2 with rich oxygen vacancies can simultaneously achieve reversed charge transfer (electrons transfer from TiO2 to Pt NCs) and enhanced hydrogen spillover from Pt NCs to the TiO2 support, which leads to electron‐rich Pt NCs being amenable to proton reduction of absorbed H*, as well as the acceleration of hydrogen desorption at Pt catalytic sites—both promoting the HER. Our work provides a new strategy for rational design of highly efficient HER catalysts.
The formation of oxygen vacancies in VO‐rich Pt/TiO2 optimizes the Gibbs free energy for hydrogen intermediate adsorption on Pt clusters, and promotes the hydrogen spillover effect from Pt clusters to the TiO2 support, which boosts the electrocatalytic hydrogen evolution reaction.
The fire detection plays a critical role in the maintenance of public security. Previous approaches of early fire warning, based on smoke or temperature response must be set in the proximity of a ...fire. They cannot provide the additional information of fire location or size and are susceptible to complicated situations. It is still a big challenge to make rapid and accurate early fire warning in precombustion because of the lack of reliable alarm signals. Herein, a precursor molecular sensor (PMS) is designed and synthesized that can present the chemical structure transformation to form phthalocyanines (Pcs) and release a color change signal at about 180 °C, learning from the plant chlorophyll metabolism. Further, the PMS is assembled to an early fire warning component (EWC) and an intelligent image recognition algorithm is introduced for unburned fire detection. The EWC generates a colorful alarm within 20 s at 275 °C. Therefore, the facile PMS provides a reliable real‐time monitoring strategy to the early fire warning detection in precombustion.
A bioinspired color changing molecular sensor is designed to achieve early fire detection based on transformation of phthalonitrile to phthalocyanine, learning from the plant chlorophyll metabolism. An intelligent image recognition algorithm is applied and the sensor generates colorful alarm within 20 s at 275 °C. This study provides a reliable real‐time monitoring strategy to the early fire detection in precombustion.
Two Pt single‐atom catalysts (SACs) of Pt‐GDY1 and Pt‐GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms ...and alkynyl C atoms in GDY, with the formation of five‐coordinated C1‐Pt‐Cl4 species in Pt‐GDY1 and four‐coordinated C2‐Pt‐Cl2 species in Pt‐GDY2. Pt‐GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt‐GDY1 and the state‐of‐the‐art commercial Pt/C catalysts, respectively. Pt‐GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|ΔGPtH*
|) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure–catalytic activity relationship in Pt SACs.
All by their selves: Two Pt single‐atom catalysts, anchored on the support of graphdiyne with tuned coordination environments, were developed. Their structure–catalytic performance relationship for hydrogen evolution were investigated.
The slow rate of extracellular electron transfer (EET) of electroactive microorganisms remains a primary bottleneck that restricts the practical applications of bioelectrochemical systems. ...Intracellular NAD(H/
) (i.e., the total level of NADH and NAD
) is a crucial source of the intracellular electron pool from which intracellular electrons are transferred to extracellular electron acceptors via EET pathways. However, how the total level of intracellular NAD(H/
) impacts the EET rate in Shewanella oneidensis has not been established. Here, we use a modular synthetic biology strategy to redirect metabolic flux towards NAD
biosynthesis via three modules: de novo, salvage, and universal biosynthesis modules in S. oneidensis MR-1. The results demonstrate that an increase in intracellular NAD(H/
) results in the transfer of more electrons from the increased oxidation of the electron donor to the EET pathways of S. oneidensis, thereby enhancing intracellular electron flux and the EET rate.
Prime editing is a novel and universal CRISPR/Cas-derived precision genome-editing technology that has been recently developed. However, low efficiency of prime editing has been shown in transgenic ...rice lines. We hypothesize that enhancing pegRNA expression could improve prime-editing efficiency. In this report, we describe two strategies for enhancing pegRNA expression. We construct a prime editing vector harboring two pegRNA variants for W542L and S621I double mutations in ZmALS1 and ZmALS2. Compared with previous reports in rice, we achieve much higher prime-editing efficiency in maize. Our results are inspiring and provide a direction for the optimization of plant prime editors.
Colorectal cancer (CRC) is a common human gastrointestinal cancer, and recent studies indicate that circular RNA (circRNA) may regulate cancer development. In this study, we assess the role of ...circRNA specifically in colorectal cancer. Our quantitative PCR assays demonstrate an upregulation of the circRNA has_circ_0020397 and a downregulation of miR-138 in CRC cells, as well as a negative correlation between these two. Using a dual-luciferase reporter assay, we show evidence of miR-138-binding sites on hsa_circ_0020397, and that overexpression of hsa_circ_0020397 could inhibit the downregulation of luciferase activity by miR-138. Although hsa_circ_0020397 did not influence miR-138 expression per se, has_circ_0020397 did inhibit miR-138 activity, as examined via the expression of miR-138 targets telomerase reverse transcriptase (TERT) and programmed death-ligand 1 (PD-L1). Control treatments with plasmids overexpressing linear hsa_circ_0020397 did not have these effects. Hsa_circ_0020397 promoted cell viability and invasion of CRC cells and inhibited their apoptosis, whereas miR-138 had the opposite effect. Nevertheless, hsa_circ_0020397 antagonized miR-138 suppression of cell growth. When TERT or PD-L1 expression was suppressed with siRNAs, the above functions of hsa_circ_0020397 were attenuated, suggesting that hsa_circ_0020397 can regulate CRC cell viability, apoptosis and invasion by promoting the expression of miR-138 target genes. These findings support the role of circRNA in CRC pathogenesis.
Intracranial aneurysm is a common life-threatening disease. Computed tomography angiography is recommended as the standard diagnosis tool; yet, interpretation can be time-consuming and challenging. ...We present a specific deep-learning-based model trained on 1,177 digital subtraction angiography verified bone-removal computed tomography angiography cases. The model has good tolerance to image quality and is tested with different manufacturers. Simulated real-world studies are conducted in consecutive internal and external cohorts, in which it achieves an improved patient-level sensitivity and lesion-level sensitivity compared to that of radiologists and expert neurosurgeons. A specific cohort of suspected acute ischemic stroke is employed and it is found that 99.0% predicted-negative cases can be trusted with high confidence, leading to a potential reduction in human workload. A prospective study is warranted to determine whether the algorithm could improve patients' care in comparison to clinicians' assessment.
The development of multifunctional bio‐based materials with closed‐loop chemically recyclable plastics can be a paramount response to the worldwide plastic waste predicament. However, the trade‐off ...dilemma between the high performance and easy recycling performance of these materials still encounters huge challenges. In this contribution, inspired by the significant contribution of the hydrogen bonding networks to enhanced mechanical and gas barrier performance as well as the cosolvents to enhance recycling performance, a novel polyester material (PBHyF) synthesized by bio‐based monomers that integrate high‐performance and efficient chemical closed‐loop is presented. PBHyF show ultra‐high mechanical properties (83.2 MPa, 233.9%) and barrier properties (CO2 0.0157 barrer, O2 0.0071 barrer, H2O 5.518E‐15 g·cm/cm2·s·Pa) that are greater than bio‐based materials and most engineering plastics of previous work. More significantly, PBHyF also exhibits multifunctionality with excellent ultraviolet shielding properties, solvent‐resistant properties, and easy recycling performance. The initial monomers of PBHyF can be obtained in exceptional yields (>90.0%) and purity (>99.0%) under mild conditions by a simple energy‐efficient rapid chemical‐solvolysis strategy, even with polyolefin blend plastics. Further possesses similar high‐performance repolymerized polyester comparable to the polyester before recycling. Hence, these state‐of‐art high‐performance and easy‐recycling bio‐based materials provide a new approach for a green, sustainable material economy.
A novel multifunctional material derived from bio‐based resources is prepared, which synchronously achieves high performance (with excellent mechanical properties (83.2 MPa, 233.9%), barrier properties (CO2 0.0157 barrer, O2 0.0071 barrer, H2O, 5.518E‐15 g·cm/cm2·s·Pa)) with an easily chemical closed‐loop (the initial monomers of the materials can be recycled in exceptional yields (>90.0%) and purity (>99.0%)).
Exosomes, which are nano-vesicles produced by most cell types, play an irreplaceable role in cell-cell communication. They are extracellular small vesicles that can delivery various cargos of DNA, ...RNAs, proteins, and lipids. Because exosomes have different secretory components under physiological conditions and pathological conditions, it has been extensively studied in the field of diseases as a therapeutic target, as a drug/gene delivery vector and as a novel cancer marker. Despite the great development in recent decades, there are still many obstacles to be overcome, for example, the separation method is not standardized with low yield and poor stability, which limit its medical application. This review mainly summarizes the main progresses of isolation and identification techniques, diversity function and medical application of exosomes in recent years.
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