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Background: Lung cancer associated with cystic airspaces is a rare disease, and a rare imaging performance of non-small cell lung cancer. Due to the lack of conventional diagnosis methods, it is difficult to rely on imaging diagnosis. Therefore, the definitive diagnosis of these neoplastic lesions remains challenging. Case presentation: We summarize the follow-up and diagnosis of a rare cystic airspaces lung metastatic carcinoma in an elderly man with annular density shadow in the right inferior lobe 2 years after surgery for squamous cell carcinoma in the left inferior lobe. Results: During the follow-up of the patient, after the lesion of the lower lobe of the right lung was enlarged, the structural and imaging characteristics were identified, and a special method was selected, namely biopsy of the lesion under the electromagnetic navigation bronchoscope, for clear diagnosis and subsequent treatment. Conclusion: For pulmonary cystic airspaces, it is important to correctly identify their imaging features. Because of the possibility of malignancy, it is essential to stop the radiological study in time and to acquire the pathological diagnosis by an appropriate method.
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ABSTRACT: In natural disasters such as earthquakes and landslides, the main problem that wounded survivors are confronted with is Crush Syndrome (CS). The aim of this study was to explore more convenient and effective early treatment measures for it.In the present study, we investigated the protective effect of fasciotomy combined with different concentration of hypertonic saline flushing with CS rats. CS model was prepared by compressing the buttocks and both lowering limbs of rats with 7.5 kg dumbbell for 4 hours. The rats were divided into 10 groups, which were normal control group, model group, incision without flushing group, 0.45%, 0.9%, 3%, 5%, 7% saline group, 3%-0.45% and 7%-0.45% saline alternating flushing group respectively. 6 hours after the treatment, the blood was sampled for measurement of the potassium, calcium, AST, ALT, Cr, Urea, myoglobin, and lactic acid content. The blood flow of the compressed tissue and kidneys, the pathological changes of the kidneys and the survival rate of 3%-0.45% saline alternating flushing group were also observed.The experimental results showed that fasciotomy alone for treatment cannot improve the presentation of CS of rats. Instead, hypertonic saline flushing significantly improved the AST, ALT, Cr, Urea indices, blood flow of muscles and kidneys. It also enormously decreased the blood K+, myoglobin, lactic acid concentration and slight increased the blood Ca2+. Among them, alternating flushing with 3%-0.45% saline had the best therapeutic effect on CS. Finally, it can be found that 3%-0.45% saline treatment regimen dramatically raised the survival rate of CS rats.All in all, this study suggests that fasciotomy combined with hypertonic saline flushing is a good therapeutic approach for CS.
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Organic polyradicals with a high-spin ground state and quantum magnetic properties suitable for spin manipulation are valuable materials for diverse innovative technologies, including quantum devices. However, the typically high reactivity and low stability of conventional polyradicals present a major obstacle to such applications. In this study, a highly stable carbon-centered triradical TR with a quartet ground state and excellent stability (τ1/2 of â¼90 days in air-saturated toluene at room temperature) is achieved, which shows apposite magnetic anisotropy and Zeeman splitting partition with favorable addressability. By virtue of the optimal stability, thorough structural and magnetic characterizations are realized. With X-ray crystallography unambiguously proving the molecular structure, the quartet ground state (ΔED-Q = 0.78 kcal/mol) is confirmed by the SQUID measurements, while the cw- and pulsed EPR techniques offer additional supportive evidence for the high-spin nature. Remarkably, owing to the easily attained magnetic anisotropy, selective excitations between different Zeeman splitting levels are successfully demonstrated with TR in its frozen toluene solution without the requirement for special alignment, which is unprecedented for organic polyradicals. Along with the millisecond spin-lattice relaxation and microsecond coherence time manifested by TR, this triradical is promising for potential coherent spin manipulation applications as a multienergy-level quantum information carrier.
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Background: The current research on advanced glycosylation end products (AGEs) and cognitive function is limited. Objective: We aimed to investigate the relationship between multiple plasma AGEs and cognitive function and mild cognitive impairment (MCI). Methods: Baseline data from The Lifestyle and Healthy Aging of Chinese Square Dancer Study was used in this cross-sectional study. Ultra-high-performance liquid chromatography tandem mass spectrometry was used to determine plasma levels of carboxymethyl lysine (CML), carboxyethyl lysine (CEL), and methyl imidazolinone (MG-H1). Four cognitive tests were used to obtain the four cognitive domain scores and the composite z scores. The Petersen criteria were used to diagnose MCI. The data were analyzed by multivariable linear and logistic regression models. Results: This study included 1,018 participants (median age 61.0 years, 87.3% female). After multivariate adjustment, the ßs of the highest quartile of CML and CEL compared to the lowest quartile were -0.28 (-0.38, -0.17) and -0.13 (-0.23, -0.03), respectively, for the composite z score. For the four cognitive domains, CML was negatively correlated with memory, attention, and executive function, and CEL was negatively associated with memory and language function. In addition, higher CML was associated with a higher odds of MCI. MG-H1 was not associated with cognitive function. Conclusions: High plasma AGE levels were correlated with poorer cognitive function, particularly CML and CEL, higher levels of CML were also associated with higher odds of MCI. To clarify the effects of different AGEs on cognitive function and the underlying mechanisms, further longitudinal and experimental studies are needed.
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Cognition , Cognitive Dysfunction , Glycation End Products, Advanced , Lysine , Humans , Female , Glycation End Products, Advanced/blood , Male , Cognitive Dysfunction/blood , Middle Aged , Cross-Sectional Studies , Cognition/physiology , Aged , Lysine/analogs & derivatives , Lysine/blood , Neuropsychological Tests/statistics & numerical data , China/epidemiologyABSTRACT
In this paper, the hydrogenation of aldehydes and ketones using the RANEY® nickel catalyst was successfully applied for the synthesis of alcohol compounds without additional column chromatographic purification. This synthetic strategy features a wide range of substrates, excellent atom economy, high chemical discrimination and the use of a ligand-free catalytic system. Reactions were performed at room temperature in water providing alcohols in high yields and purity.
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BACKGROUND: Many proteins of African swine fever virus (ASFV, such as p72, p54, p30, CD2v, K205R) have been successfully expressed and characterized. However, there are few reports on the DP96R protein of ASFV, which is the virulence protein of ASFV and plays an important role in the process of host infection and invasion of ASFV. RESULTS: Firstly, the prokaryotic expression vector of DP96R gene was constructed, the prokaryotic system was used to induce the expression of DP96R protein, and monoclonal antibody was prepared by immunizing mice. Four monoclonal cells of DP96R protein were obtained by three ELISA screening and two sub-cloning; the titer of ascites antibody was up to 1:500,000, and the monoclonal antibody could specifically recognize DP96R protein. Finally, the subtypes of the four strains of monoclonal antibodies were identified and the minimum epitopes recognized by them were determined. CONCLUSION: Monoclonal antibody against ASFV DP96R protein was successfully prepared and identified, which lays a foundation for further exploration of the structure and function of DP96R protein and ASFV diagnostic technology.
Subject(s)
African Swine Fever Virus , Antibodies, Monoclonal , Epitopes , Mice, Inbred BALB C , Viral Proteins , Animals , Female , Mice , African Swine Fever/immunology , African Swine Fever/virology , African Swine Fever Virus/immunology , Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Epitopes/immunology , Swine , Viral Proteins/immunologyABSTRACT
l-Phenylalanine (l-Phe) is widely used in the food and pharmaceutical industries. However, the biosynthesis of l-Phe using Escherichia coli remains challenging due to its lower tolerance to high concentration of l-Phe. In this study, to efficiently synthesize l-Phe, the l-Phe biosynthetic pathway was reconstructed by expressing the heterologous genes aroK1, aroL1, and pheA1, along with the native genes aroA, aroC, and tyrB in the shikimate-producing strain E. coli SA09, resulting in the engineered strain E. coli PHE03. Subsequently, adaptive evolution was conducted on E. coli PHE03 to enhance its tolerance to high concentrations of l-Phe, resulting in the strain E. coli PHE04, which reduced the cell mortality to 36.2% after 48 h of fermentation. To elucidate the potential mechanisms, transcriptional profiling was conducted, revealing MarA, a DNA-binding transcriptional dual regulator, as playing a crucial role in enhancing cell membrane integrity and fluidity for improving cell tolerance to high concentrations of l-Phe. Finally, the titer, yield, and productivity of l-Phe with E. coli PHE05 overexpressing marA were increased to 80.48 g/L, 0.27 g/g glucose, and 1.68 g/L/h in a 5-L fed-batch fermentation, respectively.
Subject(s)
Escherichia coli , Fermentation , Metabolic Engineering , Phenylalanine , Escherichia coli/genetics , Escherichia coli/metabolism , Phenylalanine/metabolism , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Biosynthetic PathwaysABSTRACT
Background: Tracheobronchopathia osteochondroplastica (TPO) is a rare, benign, chronic disorder of unknown etiology. It is characterized by submucosal nodules, often calcified, which predominantly affect the anterolateral aspects of the trachea and main bronchi, while sparing the posterior bronchial wall. The co-occurrence of TPO and lung cancer is exceedingly rare. This report presents a case of TPO association with early-stage lung cancer, which was managed through surgical intervention. No active treatment was undertaken for the TPO. Case Description: A patient presented with a nodule in the right upper lobe, which was identified during a computed tomography (CT) scan of the chest, suggestive of early-stage lung cancer. Concurrently, multiple calcifications in the cartilaginous rings of the trachea were noted. Bronchoscopy revealed distinctive "pebblestone" nodules along the anterior and lateral tracheal walls, indicative of extensive TPO. The patient underwent bronchofiberscopy, which showed patency in the bronchial lumen of the right lung's upper lobe. A biopsy was not undertaken during this procedure. Comprehensive preoperative tests, including a blood biochemical examination, tumor-marker tests, lung-function tests, head-enhanced magnetic resonance imaging, abdominal ultrasound, and whole-body bone emission CT revealed no significant abnormalities. Despite this, the patient declined a whole-body positron emission tomography (PET)-CT scan. Given the potential malignancy of nodules in the right lung's upper lobe, the lobectomy for lung cancer was carried out, a procedure that would have proceeded irrespective of the presence or absence of TPO. Preoperative planning for potential tracheal intubation difficulties involved consultation with the anesthesiologist, resulting in a smooth intraoperative process. The pathology confirmed invasive adenocarcinoma. Post-surgery, the patient developed an infection in the right lung's lower lobe, identified as pseudomonas aeruginosa and Klebsiella pneumoniae through sputum culture and bronchoscopic lavage. Treatment with meropenem for 2 weeks, as guided by drug sensitivity results and respiratory advice, led to an improvement, allowing for discharge. A follow-up lung CT four months post-operation showed inflammation absorption in the right lower lobe. Conclusions: Surgical resection in cases of TPO association with lung cancer may have an increased risk of postoperative pulmonary infection. Proactive intraoperative sputum aspiration by anesthesiologists and the postoperative reinforcement of anti-infection measures, guided by drug sensitivity results, are recommended.
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BACKGROUND: DNA methylation is an important epigenetic mode of genomic DNA modification and plays a vital role in maintaining epigenetic content and regulating gene expression. Cytosine-5 DNA methyltransferase (C5-MTase) are the key enzymes in the process of DNA methylation. However, there is no systematic analysis of the C5-MTase in cotton so far, and the function of DNMT2 genes has not been studied. METHODS: In this study, the whole genome of cotton C5-MTase coding genes was identified and analyzed using a bioinformatics method based on information from the cotton genome, and the function of GhDMT6 was further validated by VIGS experiments and subcellular localization analysis. RESULTS: 33 C5-MTases were identified from three cotton genomes, and were divided into four subfamilies by systematic evolutionary analysis. After the protein domain alignment of C5-MTases in cotton, 6 highly conserved motifs were found in the C-terminus of 33 proteins involved in methylation modification, which indicated that C5-MTases had a basic catalytic methylation function. These proteins were divided into four classes based on the N-terminal difference, of which DNMT2 lacks the N-terminal regulatory domain. The expression of C5-MTases in different parts of cotton was different under different stress treatments, which indicated the functional diversity of cotton C5-MTase gene family. Among the C5-MTases, the GhDMT6 had a obvious up-regulated expression. After silencing GhDMT6 with VIGS, the phenotype of cotton seedlings under different stress treatments showed a significant difference. Compared with cotton seedlings that did not silence GhDMT6, cotton seedlings silencing GhDMT6 showed significant stress resistance. CONCLUSION: The results show that C5-MTases plays an important role in cotton stress response, which is beneficial to further explore the function of DNMT2 subfamily genes.
Subject(s)
Droughts , Gossypium , Gossypium/genetics , Gossypium/enzymology , Plant Proteins/genetics , Plant Proteins/metabolism , DNA Methylation , Gene Expression Regulation, Plant , Salt Tolerance/genetics , Multigene Family , DNA (Cytosine-5-)-Methyltransferases/genetics , DNA (Cytosine-5-)-Methyltransferases/metabolism , Phylogeny , Genome, Plant , Genes, PlantABSTRACT
NaYF4 systems have been widely studied as up-conversion host matrices, and their phase transitions are flexible and worth investigating in great detail. Herein, the evolution of morphology and crystal structure of a Eu3+-doped ß-NaYF4 single nanoparticle heated in an air atmosphere was investigated using in situ transmission electron microscopy (TEM). The annealing process revealed that the hexagonal ß-NaYF4 phase undergoes sequential transformations into high-temperature cubic phases at both 350 °C and 500 °C. The emission characteristics of Eu3+ in the single nanoparticle after heating treatment were also analyzed using Correlative Cathodoluminescence Electron Microscopy (CCLEM). The results of CCLEM suggest a gradual decrease followed by a subsequent increase in structural symmetry. A comprehensive spectroscopic and structural analysis encapsulates the entire transformation process as NaYF4 â YOF â Y2O3. In situ energy dispersive spectroscopy analyses (EDS) support this reaction process. The aforementioned technique yields correlative lattice-resolved TEM images and nanoscale spectroscopic information, which can be employed to assess the structure-function relationships on the nanoscale.
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P-coumaric acid (p-CA), a pant metabolite with antioxidant and anti-inflammatory activity, is extensively utilized in biomedicine, food, and cosmetics industry. In this study, a synthetic pathway (PAL) for p-CA was designed, integrating three enzymes (AtPAL2, AtC4H, AtATR2) into a higher l-phenylalanine-producing strain Escherichia coli PHE05. However, the lower soluble expression and activity of AtC4H in the PAL pathway was a bottleneck for increasing p-CA titers. To overcome this limitation, the soluble expression of AtC4H was enhanced through N-terminal modifications. And an optimal mutant, AtC4HL373T/G211H, which exhibited a 4.3-fold higher kcat/Km value compared to the wild type, was developed. In addition, metabolic engineering strategies were employed to increase the intracellular NADPH pool. Overexpression of ppnk in engineered E. coli PHCA20 led to a 13.9-folds, 1.3-folds, and 29.1% in NADPH content, the NADPH/NADP+ ratio and p-CA titer, respectively. These optimizations significantly enhance p-CA production, in a 5-L fermenter using fed-batch fermentation, the p-CA titer, yield and productivity of engineered strain E. coli PHCA20 were 3.09 g/L, 20.01 mg/g glucose, and 49.05 mg/L/h, respectively. The results presented here provide a novel way to efficiently produce the plant metabolites using an industrial strain.
Subject(s)
Coumaric Acids , Escherichia coli , Glucose , Metabolic Engineering , Propionates , Escherichia coli/genetics , Escherichia coli/metabolism , Coumaric Acids/metabolism , Metabolic Engineering/methods , Glucose/metabolism , Propionates/metabolismABSTRACT
OBJECTIVES: The objective of this study was to examine the association between dietary diversity and sleep quality among Chinese middle-aged and older adults. METHODS: The Lifestyle and Healthy Aging of Chinese Square Dancer Study is a prospective, community-based cohort study that enrolled participants aged 45 years and above from 2020 to 2021. Using the semiquantitative food frequency questionnaire to investigate the diets of study participants, and using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Dietary diversity was assessed using two scoring methods covering ten food groups and 66 food items, respectively: the dietary diversity score (DDS) and the food variety score (FVS). The higher scores of DDS and FVS indicated greater dietary diversity and higher dietary quality. Logistic regression analysis explored the associations between these scores and sleep quality. RESULTS: A total of 2409 individuals with completed information on PSQI and FFQ were included in this study, of whom 767 (31.8%) had poor sleep quality. Participants with higher DDS were associated with an 18% lower odds of poor sleep quality compared to those with low DDS (OR = 0.82, 95% CI, 0.68-0.98). Participants in the highest quartile of the FVS had a 32% lower odds of poor sleep quality than those in the lowest quartile (OR = 0.68, 95% CI, 0.52-0.89). CONCLUSIONS: There was a positive correlation between higher FVS and DDS with better sleep quality. Therefore, ensuring a diverse diet may be beneficial for maintaining good sleep quality among middle-aged and older adults.
Subject(s)
Diet , Sleep Quality , Humans , Male , Female , Middle Aged , Aged , China , Prospective Studies , Diet/statistics & numerical data , Cohort Studies , Surveys and Questionnaires , East Asian PeopleABSTRACT
The Rh(III)-catalyzed annulation of benzoic acids with nitroalkenes was disclosed to afford a wide range of 3,4-disubstituted isochroman-1-ones with excellent regioselectivity and high catalytic efficiency. Both aromatic and aliphatic nitroalkenes participated in this cyclization reaction successfully. The synthetic value of 3,4-disubstituted isochroman-1-ones was proven by a series of derivatizations. Furthermore, a reliable mechanism is outlined on the basis of experimental investigations and related precedents.
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Spinal cord injury (SCI) is a disturbance of peripheral and central nerve conduction that causes disability in sensory and motor function. Currently, there is no effective treatment for SCI. Mitophagy plays a vital role in mitochondrial quality control during various physiological and pathological processes. The study aimed to elucidate the role of mitophagy and identify potential mitophagy-related hub genes in SCI pathophysiology. Two datasets (GSE15878 and GSE138637) were analyzed. Firstly, the differentially expressed genes (DEGs) were identified and mitophagy-related genes were obtained from GeneCards, then the intersection between SCI and mitophagy-related genes was determined. Next, we performed gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), protein-protein interaction network (PPI network), least absolute shrinkage and selection operator (LASSO), and cluster analysis to identify and define the hub genes in SCI. Finally, the link between hub genes and infiltrating immune cells was investigated and the potential transcriptional regulation/small molecular compounds to target hub genes were predicted. In total, SKP1 and BAP1 were identified as hub genes of mitophagy-related DEGs during SCI development and regulatory T cells (Tregs)/resting NK cells/activated mast cells may play an essential role in the progression of SCI. LINC00324 and SNHG16 may regulate SKP1 and BAP1, respectively, through miRNAs. Eleven and eight transcriptional factors (TFs) regulate SKP1 and BAP1, respectively, and six small molecular compounds target BAP1. Then, the mRNA expression levels of BAP1 and SKP1 were detected in the injured sites of spinal cord of SD rats at 6 h and 72 h after injury using RT-qPCR, and found that the level were decreased. Therefore, the pathways of mitophagy are downregulated during the pathophysiology of SCI, and SKP1 and BAP1 could be accessible targets for diagnosing and treating SCI.
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The development of facile methods for constructing highly active, cost-effective catalysts that meet ampere-level current density and durability requirements for an oxygen evolution reaction is crucial. Herein, a general topochemical transformation strategy is posited: M-Co9S8 single-atom catalysts (SACs) are directly converted into M-CoOOH-TT (M = W, Mo, Mn, V) pair-sites catalysts under the role of incorporating of atomically dispersed high-valence metals modulators through potential cycling. Furthermore, in situ X-ray absorption fine structure spectroscopy is used to track the dynamic topochemical transformation process at the atomic level. The W-Co9S8 breaks through the low overpotential of 160 mV at 10 mA cm-2. A series of pair-site catalysts exhibit a large current density of approaching 1760 mA cm-2 at 1.68 V vs reversible hydrogen electrode (RHE) in alkaline water oxidation and achieve a ≈240-fold enhancement in the normalized intrinsic activity compare to that reported CoOOH, and sustainable stability of 1000 h. Moreover, the OâO bond formation is confirmed via a two-site mechanism, supported by in situ synchrotron radiation infrared and density functional theory (DFT) simulations, which breaks the limit of adsorption-energy scaling relationship on conventional single-site.
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BACKGROUND: Abelson tyrosine kinase (c-Abl) is frequently mutated and highly expressed, and promotes non-small-cell lung cancer (NSCLC) survival, metastasis and tumorigenesis. c-Abl could also be modified through ubiquitination, but the underlying mechanism is not well understood. METHODS: Mass spectrometry assays were performed to search c-Abl deubiquitination enzymes. The molecular mechanism was determined using Co-IP assays, pull-down assays, Western blotting upon gene knockdown or overexpression. Cell lines and animal models were used to investigate the role of c-Abl and USP7 in NSCLC. EdU staining assay and Transwell assay were performed to evaluate the proliferation and migration ability of NSCLC cells, respectively. RESULTS: Ubiquitin-specific protease 7 (USP7) is found to upregulate c-Abl via the deubiquitinase screen. USP7 interacts with c-Abl and decreases its K48-linked polyubiquitination, thereby increasing the stability of c-Abl. In addition to the wild-type one, c-Abl mutants can also be deubiquitinated and stabilized by USP7. Moreover, USP7 promotes c-Abl accumulation in cytoplasm by increasing its binding to 14-3-3α/ß and activates the oncogenic c-Abl signalling pathway. Furthermore, the USP7/c-Abl axis promotes NSCLC cell glycolysis by direct phosphorylating and stabilizing hexokinase-2 (HK2). Knockdown of USP7 or c-Abl suppresses NSCLC cell glycolysis and reduces lactate production. Further studies revealed that overexpression of USP7 facilitates NSCLC cell growth and metastasis as well as xenograft growth in nude mice, while these activities are suppressed with USP7 or c-Abl being knocked down. CONCLUSIONS: USP7 is a deubiquitinase of c-Abl and upregulates its oncogenic activity. USP7 promotes NSCLC cell metabolism by activating c-Abl and HK2. Targeting the USP7/c-Abl/HK2 axis might be a potential strategy to the precision therapy of NSCLC.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Animals , Mice , Humans , Carcinoma, Non-Small-Cell Lung/metabolism , Lung Neoplasms/metabolism , Ubiquitin-Specific Peptidase 7/genetics , Ubiquitin-Specific Peptidase 7/metabolism , Mice, Nude , Glycolysis/geneticsABSTRACT
Deciphering the three-dimensional (3D) insight into nanocatalyst surfaces at the atomic level is crucial to understanding catalytic reaction mechanisms and developing high-performance catalysts. Nevertheless, better understanding the inherent insufficiency of a long-range ordered lattice in nanocatalysts is a big challenge. In this work, we report the local structure of Pd nanocatalysts, which is beneficial for demonstrating the shape-structure-adsorption relationship in acetylene hydrogenation. The 5.27 nm spherical Pd catalyst (Pdsph) shows an ethylene selectivity of 88% at complete acetylene conversion, which is much higher than those of the Pd octahedron and Pd cube and superior to other reported monometallic Pd nanocatalysts so far. By virtue of the local structure revelation combined with the atomic pair distribution function (PDF) and reverse Monte Carlo (RMC) simulation, the atomic surface distribution of the unique compressed strain of Pd-Pd pairs in Pdsph was revealed. Density functional theory calculations verified the obvious weakening of the ethylene adsorption energy on account of the surface strain of Pdsph. It is the main factor to avoid the over-hydrogenation of acetylene. The present work, entailing shape-induced surface strain manipulation and atomic 3D insight, opens a new path to understand and optimize chemical activity and selectivity in the heterogeneous catalysis process.
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Stable carbon-based polyradicals exhibiting strong spin-spin coupling and slow depolarization processes are particularly attractive functional materials. A new molecular motif synthesized by a convenient method that allows the integration of stable, high-spin radicals to (hetero)aromatic polycycles has been developed, as illustrated by a non-Kekulé diradical showing a triplet ground state with long persistency (τ1/2 ≈31â h) in air. Compared to the widely used 1,3-phenylene, the newly designed (diaza)pyrene-4,10-diyl moiety is for the first time demonstrated to confer ferromagnetic (FM) spin coupling, allowing delocalized non-disjoint SOMOs. With the X-ray crystallography unambiguously proving the diradical structure, the triplet ground state was thoroughly characterized. A large ΔES-T of 1.1â kcal/mol, proving the strong FM coupling effect, was revealed consistently by superconducting quantum interference device (SQUID) measurements and variable-temperature electron paramagnetic resonance (EPR) spectroscopy, while the zero-field splitting and triplet nutation characters were examined by continuous-wave and pulsed EPR spectroscopy. A millisecond spin-lattice relaxation time was also detected. The current study not only offers a new molecular motif enabling FM coupling between carbon-based spins, but more importantly presents a general method for installing stable polyradicals into functional π-systems.
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Developing cost-effective and sustainable acidic water oxidation catalysts requires significant advances in material design and in-depth mechanism understanding for proton exchange membrane water electrolysis. Herein, we developed a single atom regulatory strategy to construct Co-Co dinuclear active sites (DASs) catalysts that atomically dispersed zirconium doped Co9 S8 /Co3 O4 heterostructure. The X-ray absorption fine structure elucidated the incorporation of Zr greatly facilitated the generation of Co-Co DASs layer with stretching of cobalt oxygen bond and S-Co-O heterogeneous grain boundaries interfaces, engineering attractive activity of significantly reduced overpotential of 75â mV at 10â mA cm-2 , a breakthrough of 500â mA cm-2 high current density, and water splitting stability of 500â hours in acid, making it one of the best-performing acid-stable OER non-noble metal materials. The optimized catalyst with interatomic Co-Co distance (ca. 2.80â Å) followed oxo-oxo coupling mechanism that involved obvious oxygen bridges on dinuclear Co sites (1,090â cm-1 ), confirmed by in situ SR-FTIR, XAFS and theoretical simulations. Furthermore, a major breakthrough of 120,000â mA g-1 high mass current density using the first reported noble metal-free cobalt anode catalyst of Co-Co DASs/ZCC in PEM-WE at 2.14â V was recorded.