RESUMO
The heart is an autoimmune-prone organ. It is crucial for the heart to keep injury-induced autoimmunity in check to avoid autoimmune-mediated inflammatory disease. However, little is known about how injury-induced autoimmunity is constrained in hearts. Here, we reveal an unknown intramyocardial immunosuppressive program driven by Tbx1, a DiGeorge syndrome disease gene that encodes a T-box transcription factor (TF). We found induced profound lymphangiogenic and immunomodulatory gene expression changes in lymphatic endothelial cells (LECs) after myocardial infarction (MI). The activated LECs penetrated the infarcted area and functioned as intramyocardial immune hubs to increase the numbers of tolerogenic dendritic cells (tDCs) and regulatory T (Treg) cells through the chemokine Ccl21 and integrin Icam1, thereby inhibiting the expansion of autoreactive CD8+ T cells and promoting reparative macrophage expansion to facilitate post-MI repair. Mimicking its timing and implementation may be an additional approach to treating autoimmunity-mediated cardiac diseases.
RESUMO
Plants have evolved a sophisticated immune system to defend against invasion by pathogens. In response, pathogens deploy copious effectors to evade the immune responses. However, the molecular mechanisms used by pathogen effectors to suppress plant immunity remain unclear. Herein, we report that an effector secreted by Ralstonia solanacearum, RipAK, modulates the transcriptional activity of the ethylene-responsive factor ERF098 to suppress immunity and dehydration tolerance, which causes bacterial wilt in pepper (Capsicum annuum L.) plants. Silencing ERF098 enhances the resistance of pepper plants to R. solanacearum infection not only by inhibiting the host colonization of R. solanacearum but also by increasing the immunity and tolerance of pepper plants to dehydration and including the closure of stomata to reduce the loss of water in an abscisic acid signal-dependent manner. In contrast, the ectopic expression of ERF098 in Nicotiana benthamiana enhances wilt disease. We also show that RipAK targets and inhibits the ERF098 homodimerization to repress the expression of salicylic acid-dependent PR1 and dehydration tolerance-related OSR1 and OSM1 by cis-elements in their promoters. Taken together, our study reveals a regulatory mechanism used by the R. solanacearum effector RipAK to increase virulence by specifically inhibiting the homodimerization of ERF098 and reprogramming the transcription of PR1, OSR1, and OSM1 to boost susceptibility and dehydration sensitivity. Thus, our study sheds light on a previously unidentified strategy by which a pathogen simultaneously suppresses plant immunity and tolerance to dehydration by secreting an effector to interfere with the activity of a transcription factor and manipulate plant transcriptional programs.
Assuntos
Capsicum , Ralstonia solanacearum , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ralstonia solanacearum/fisiologia , Desidratação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Imunidade Vegetal/genética , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/microbiologia , Capsicum/metabolismo , Resistência à Doença/genéticaRESUMO
The glycerol oxidation reaction (GOR) run with photoelectrochemical cells (PECs) is one of the most promising ways to upgrade biomass because it is thermodynamically favorable, while irreversible overoxidation leads to unsatisfactory product selectivities. Herein, a tunable one-dimensional nanoconfined environment was introduced into the GOR process, which accelerated mass transfer of glycerol via the microscale fluid effect and changed the main oxidation product from formic acid (FA) to glyceraldehyde (GLD), which led to retention of the heavier multicarbon products. The rate of glycerol diffusion in the nanochannels increased by a factor of 4.92 with decreasing inner diameters. The main product from the PEC-selective oxidation of glycerol changed from the C1 product FA to the C3 product GLD with a great selectivity of 60.7%. This work provides a favorable approach for inhibiting further oxidation of multicarbon products and illustrates the importance of microenvironmental regulation in biomass oxidation.
RESUMO
Lithium-carbon dioxide (Li-CO2) batteries offer the possibility of synchronous implementation of carbon neutrality and the development of advanced energy storage devices. The exploration of low-cost and efficient cathode catalysts is key to the improvement of Li-CO2 batteries. Herein, high-entropy alloys (HEAs)@C hierarchical nanosheet is synthesized from the simulation of the recycling solution of waste batteries to construct a cathode for the first time. Owing to the excellent electrical conductivity of the carbon material, the unique high-entropy effect of the HEAs, and the large number of catalytically active sites exposed by the hierarchical structure, the FeCoNiMnCuAl@C-based battery exhibits a superior discharge capability of 27664 mAh g-1 and outstanding durability of 134 cycles as well as low overpotential with 1.05 V at a discharge/recharge rate of 100 mA g-1. The adsorption capacity of different sites on the HEAs is deeply understood through density functional theory calculations combined with experiments. This work opens up the application of HEAs in Li-CO2 batteries catalytic cathodes and provides unique insights into the study of adsorption active sites in HEAs.
RESUMO
The synthesis of stable polynitrogen compounds with high-energy density has long been a major challenge. The cyclo-pentazolate anion (cyclo-N5 -) is successfully converted into aromatic and structurally symmetric bipentazole (N10) via electrochemical synthesis using highly conductive multi-walled carbon nanotubes (MWCNTs) as the substrate and sodium pentazolate hydrate ([Na(H2O)(N5)]·2H2O) as the raw material. Attenuated total refraction Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and density functional theory calculations confirmed the structure and homogeneous distribution of N10 in the sidewalls of the MWCNTs (named MWCNT-N10-n m). The MWCNT-N10-2.0 m is further used as a catalyst for electrochemical oxygen reduction to synthesize hydrogen peroxide from oxygen with a two-electron selectivity of up to 95%.
RESUMO
A novel polycyclic naphthoxazine resin (NSA-thiq) is synthesized via N, O-acetal forming reaction between o-hydroxyl naphthaldehyde and 1,2,3,4-tetrahydroisoquinoline. The chemical structure of the monomer is investigated and confirmed by 1H and 13C NMR, Fourier-transform infrared (FT-IR) spectroscopy, and high-resolution mass spectrometry. Besides, the ring-opening polymerization behavior similar to ordinary benzoxazine resins is observed by differential scanning calorimetry (DSC) and in situ FT-IR analyses, leading to the formation of the phenolic cross-linked network. Notably, DSC thermograms indicate that the newly obtained polycyclic naphthoxazine resin exhibits much lower polymerization temperatures compared to many other reported benzoxazine or naphthoxazine resins. Moreover, the corresponding polybenzoxazine (poly(NSA-thiq)) shows comparable thermal stability in comparison with thermosets derived from monobenzoxazine resins. As a consequence of these unique performances, NSA-thiq is applied as a property modifier for a commercialized benzoxazine resin (BA-a). The glass transition temperature of copolymeric thermosets is enhanced without sacrificing too much thermal stability and heat resistance. Here, another series of naphthoxazine thermosetting resin is explored, which can provide more examples for constructing composites based on thermoset polymers.
RESUMO
OBJECTIVES: As a heterogeneous disease, asthma is characterized by airway hyperresponsiveness, airway inflammation, and airway mucus hypersecretion. According to the pathological changes, symptoms, preventive and treatment methods, asthma can be divided into TH2-high and TH2-low asthma. We show that the expression of the tumor biomarker human epididymis protein 4 (HE4) was significantly increased in TH2-high asthma group, while there was no marked difference in its expression between TH2-low asthma and healthy control groups. HE4 levels were significantly increased in plasma, induced sputum, and alveolar lavage fluid (BALF) samples and airway epithelial cells from TH2-high asthma group, showing that HE4 has a possible role in the pathogenesis of TH2-high asthma. METHODS: Using RT-qPCR, ELISA, Western blot (WB), and immunohistochemistry, we assessed differences in HE4 expression in plasma, induced sputum, BALF, and airway epithelial cells among patients with the TH2-related asthma subtypes and healthy controls. To explore the role of HE4 in TH2-high asthma, we conducted a correlation analysis between HE4 levels in plasma, induced sputum, BALF, and airway epithelial cells and multiple indicators of airway eosinophilic inflammation, airway mucus secretion, and airway remodeling. CONCLUSION: We found for the first time that HE4 was differentially expressed in the TH2-related asthma subtypes. In TH2-high asthma, HE4 levels were markedly elevated in airway epithelial cells, plasma, induced sputum, and BALF. HE4 may play an important role in various pathogenic mechanisms of asthma, such as airway eosinophilic inflammation, airway mucus secretion, and airway remodeling. HE4 in plasma may be a clinically biomarker for differentiating TH2-related asthma subtypes.
Assuntos
Asma , Humanos , Animais , Camundongos , Asma/patologia , Remodelação das Vias Aéreas , Sistema Respiratório , Inflamação/patologia , Líquido da Lavagem Broncoalveolar , Modelos Animais de Doenças , Camundongos Endogâmicos BALB C , Ovalbumina/farmacologiaRESUMO
OBJECTIVE: To explore the influence of nutritional status on adverse clinical events in elderly patients with nonvalvular atrial fibrillation. METHODS: This retrospective observational cohort study included 196 patients, 75-102-years-old, with nonvalvular atrial fibrillation, hospitalized in our hospital. The nutritional status was assessed using Mini-Nutritional Assessment-Short Form (MNA-SF). Patients with MNA-SF scores of 0-11 and 12-14 were included in the malnutrition and nonmalnutrition groups, respectively. RESULTS: The average age of the malnutrition group was higher than that of the nonmalnutrition group, and the levels of body mass index (BMI), hemoglobin (HGB), and albumin (ALB) were significantly lower than those of the nonmalnutrition group, with statistical significance (p < .05). The incidence of all-cause death in the malnutrition group was higher than that in the nonmalnutrition group (p = .007). Kaplan-Meier curve indicated that malnutrition patients have a higher risk of all-cause death (log-rank test, p = .001) and major bleeding events (p = .017). Multivariate Cox proportional hazard regression analysis corrected for confounders showed that malnutrition was an independent risk factor of all-cause death (HR = 1.780, 95%CI:1.039-3.050, p = .036). The malnutrition group had a significantly high incidence of major bleeding than the nonmalnutrition group (p = .026), and there was no significant difference in the proportion of anticoagulation therapy (p = .082) and the incidence of ischemic stroke/systemic embolism (p = .310) between the two groups. CONCLUSIONS: Malnutrition is an independent risk factor of all-cause death in elderly patients with atrial fibrillation. The incidence of major bleeding in malnourished elderly patients with atrial fibrillation is high, and the benefit of anticoagulation therapy is not obvious.
Assuntos
Fibrilação Atrial , Desnutrição , Estado Nutricional , Humanos , Fibrilação Atrial/complicações , Fibrilação Atrial/epidemiologia , Estudos Retrospectivos , Feminino , Masculino , Idoso , Idoso de 80 Anos ou mais , Desnutrição/complicações , Estudos de Coortes , Fatores de Risco , Avaliação Nutricional , Avaliação Geriátrica/métodos , Avaliação Geriátrica/estatística & dados numéricosRESUMO
OBJECTIVE: The current work was designed to compare the effects of ciprofol and propofol on left ventricular systolic function and myocardial work by noninvasive speckle-tracking echocardiography in children undergoing surgical repair of atrial septal or ventricular septal defects. DESIGN: A single-center double-blind randomized noninferiority study was conducted. SETTING: The research occurred at a tertiary care center affiliated with Shanghai Jiao Tong University, China. PARTICIPANTS: One hundred and twelve children aged 1 month to 16 years undergoing atrial septal or ventricular septal defect surgery with cardiopulmonary bypass were included. INTERVENTIONS: One hundred and twelve children were allocated randomly to receive ciprofol (n = 67) or propofol (n = 45) in a 1.5:1 ratio. Ciprofol or propofol were intravenously infused at loading doses of 0.4 mg/kg or 2.0 mg/kg, respectively, over 30 seconds, depending on the physical condition of each patient. When the bispectral index was maintained between 45 and 55 after induction, transthoracic echocardiography, including apical two-chamber, three-chamber, and four-chamber views, were collected bedside. MEASUREMENTS AND MAIN RESULTS: Of the 112 patients enrolled, 104 completed the study. Global longitudinal strain in the ciprofol and propofol groups after anesthesia was -17.3% (95% confidence interval [CI] -18.0% to -16.6%) and -17.8% (95% CI -18.7 to -17.0%) in the full analysis set and -17.5% (95% CI -18.2% to -16.9%) and -17.8% (95% CI -18.7% to -17.0%) in the per-protocol set, respectively. The noninferiority margin was set at 2% and confirmed with a lower limit of two-sided 95% CI for the intergroup difference of 1.58% in the full analysis set and 1.34% in the per-protocol set. There were no significant differences between the groups in left ventricular systolic and diastolic function and myocardial work indices. Postoperative vasoactive-inotropic score, NT-proBNP, duration of mechanical ventilation, and the length of stay in the cardiac intensive care unit and hospital were also comparable between the two groups (all p > 0.05). CONCLUSIONS: Ciprofol did not show different effects on myocardial function and postoperative outcomes from propofol. Further, on the sensitive cardiac systole marker global longitudinal strain, ciprofol demonstrated noninferiority to propofol. Ciprofol might be an alternative solution for cardiac anesthesia in children with congestive heart disease with mild lesion.
RESUMO
The topological diversity of covalent organic frameworks (COFs) enables considerable space for exploring their structure-performance relationships. In this study, we report a sequence of novel 1D COFs (EO, ES, and ESe-COF) with typical 4-c sql topology that can be interconnected with VIA group elements (O, S, and Se) via a modular design strategy. It is found that the electronic structures, charge delivery property, light harvesting ability, and hydrophilicity of these 1D COFs can be profoundly influenced by the bridge-linked atom ordinal. Finally, EO-COF, possessing the highest quantity of active sites, the longest lifetime of the active electron, the strongest interaction with O2 , and the lowest energy barrier of O2 reduction, exhibits exceptional photocatalytic O2 -to-H2 O2 activity under visible light, with a production rate of 2675â µmol g-1 h-1 and a high apparent quantum yield of 6.57 % at 450â nm. This is the first systematic report on 1D COFs for H2 O2 photosynthesis, which enriches the topological database in reticular chemistry and promotes the exploration of structure-catalysis correlation.
RESUMO
Directional organic transformation via a green, sustainable catalytic reaction has attracted a lot of attention. Herein, we report a photoelectrochemical approach for highly selective epoxidation of alkenes in a salt solution using Co2 (OH)3 Cl (CoOCl) as a bridge of photo-generated charge, where the lattice Cl- of CoOCl can be oxidized to generate HClO by the photo-generated holes of BiVO4 photoanode and be spontaneously recovered by Cl- of a salt solution, which then oxidizes the alkenes into the corresponding epoxides. As a result, a series of water-soluble alkenes, including 4-vinylbenzenesulfonic acid sodium, 2-methyl-2-propene-1-sulfonic acid sodium, and 3-methyl-3-buten-1-ol can be epoxidized with near 100 % conversion rate and selectivity. Through further inserting a MoOx protection layer between BiVO4 and CoOCl, the stability of CoOCl-MoOx /BiVO4 can be maintained for at least 120â hours. This work opens an avenue for solar-driven organic epoxidation with a possibility of on-site reaction around the abundant ocean.
RESUMO
Photocatalytic oxygen reductive H2O2 production is a promising approach to alternative industrial anthraquinone processes while suffering from the requirement of pure O2 feedstock for practical application. Herein, we report a spaced double hydrogen bond (IC-H-bond) through multi-component Radziszewski reaction in an imidazole poly-ionic-liquid composite (SI-PIL-TiO2) and levofloxacin hydrochloride (LEV) electron donor for highly efficient and selective photocatalytic air reductive H2O2 production. It is found that the IC-H-bond formed by spaced imino (-NH-) group of SI-PIL-TiO2 and carbonyl (-C=O) group of LEV can switch the imidazole active sites characteristic from a covered state to a fully exposed one to shield the strong adsorption of electron donor and N2 in the air, and propel an intenser positive potential and more efficient orbitals binding patterns of SI-PIL-TiO2 surface to establish competitive active sites for selectivity O2 chemisorption. Moreover, the high electron enrichment of imidazole as an active site for the 2e- oxygen reduction ensures the rapid reduction of O2. Therefore, the IC-H-bond enables a total O2 utilization and conversion efficiency of 94.8 % from direct photocatalytic air reduction, achieving a H2O2 production rate of 1518â µmol/g/h that is 16 and 23â times compared to poly-ionic-liquid composite without spaced imino groups (PIL-TiO2) and TiO2, respectively.
RESUMO
Prostate cancer (PC) is a clinically and biologically heterogeneous disease that lacks effective treatment. Heat shock protein B8 (HSPB8) is an important factor in the progression of various types of cancer. However, the clinical significance and biological role of HSPB8 in PC are still unclear. In this study, we determined HSPB8 expression in PC tissues by immunohistochemical staining and explored the in vitro functions of HSPB8 using HSPB8 knockdown DU145 and LNcap PC cell lines. The in vivo effect of HSPB8 was explored by a subcutaneous xenograft mice model. The human phospho-kinase array and signal transducer and activator of transcription (STAT) 3 activator were utilized to explore the potential mechanism of HSPB8-induced PC progression. As a result, we found that HSPB8 was abundantly expressed in PC tissues and cell lines. HSPB8 knockdown inhibited cell proliferation and migration, promoted apoptosis and cycle repression, as well as weakened tumorigenesis ability. Mechanistically, we demonstrated that HSPB8 facilitates the malignant phenotypes of PC by activating the Janus kinase/STAT3 signaling pathway. These results proposed that HSPB8 seems to be an attractive therapeutic target for PC patients.
Assuntos
Proteínas de Choque Térmico , Neoplasias da Próstata , Masculino , Humanos , Animais , Camundongos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Janus Quinases/metabolismo , Janus Quinases/farmacologia , Transdução de Sinais , Neoplasias da Próstata/metabolismo , Próstata/metabolismo , Proliferação de Células/genética , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Linhagem Celular Tumoral , Apoptose , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/farmacologiaRESUMO
Facile synthesis of hierarchically porous metal-organic frameworks (MOFs) with adjustable porosity and high crystallinity attracts great attention yet remains challenging. Herein, a micromolar amount of dye-based modulator (Rhodamine B (RhB)) is employed to easily and controllably tailor the pore size of a Ti-based metal-organic framework (MIL-125-NH2 ). The RhB used in this method is easily removed by washing or photodegradation, avoiding secondary posttreatment. It is demonstrated that the carboxyl functional group and the steric effects of RhB are indispensable for enlarging the pore size of the MIL-125-NH2 . The resulting hierarchically porous MIL-125-NH2 (RH-MIL-125-NH2 ) exhibits optimized adsorption and photocatalytic activity because the newly formed mesopore with defects concurrently facilitates mass transport of guest molecules (toluene) and photogenerated charge separation. This work offers a meaningful basis for the construction of hierarchically porous MOFs and demonstrates the superiority of the hierarchical pore structure for adsorption and heterogeneous catalysis.
RESUMO
BACKGROUND: Endometriosis is still a difficult problem for women. The Nuclear Ubiquitous Casein and cyclin-dependent Kinase Substrate 1 (NUCKS1) gene is located on human chromosome 1q32.1. It encodes the NUCKS1 protein, a 27 kDa nuclear DNA binding protein that plays an important role in cell growth and proliferation. NUCKS1 plays an important role in the development of many diseases. However, its role in endometriosis is unclear. METHODS: Ectopic endometrial tissues and normal tissue specimens were collected, and the expression of NUCKS1, NF-κB and PI3K was detected by RT-qPCR and immunohistochemistry. Inhibition of NUCKS1 in hEM15A cells, study the changes in cell viability, apoptosis, migration and protein expression by CCK8 assay, flow cytometry, wound-healing assay, western blot and ELISA techniques. The comparison of differences between the two groups was implemented using unpaired sample t test or Mann-whitney U test. One-way analysis of variance or Kruskal-wallis test was used for comparisons among the three groups. RESULTS: (1) NUCKS1 is highly expressed in endometriosis tissues. (2) Inhibition of NUCKS1 decreases cell viability and capability of migration, and increases apoptosis in endometriosis cells. (3) Expressions of NF-κB and PI3K are increased in endometriosis tissues, and inhibition of NUCKS1 decreases the expression levels of PI3K and NF-κB in endometriosis cells. (4) Inhibition of NUCKS1 decreases the expression of VEGF. CONCLUSION: (1) NUCKS1 is overexpressed in endometriosis, and inhibition of NUCKS1 inhibits cell viability and capability of migration, and increases apoptosis. (2) NUCKS1 promotes the progress of endometriosis through activating PI3K and NF-κB pathways, and VEFG is also involved in this process.
Assuntos
Endometriose , NF-kappa B , Feminino , Humanos , Endometriose/genética , Endometriose/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/genéticaRESUMO
BACKGROUND: Rapidly progressive dementia (RPD) is a syndrome originating from various diseases. Recent advances have allowed a better understanding of its categories and spectrum; however, it remains challenging to make an accurate differential diagnosis and prognosis prediction. METHODS: This study was a retrospective evaluation of all participants admitted to the neurology department of a single center in China from January 2015 to December 2019. The screened patients met the RPD criteria and their characteristics were collected to explore a diagnostic pattern of RPD. In addition, outcomes of RPD were evaluated with the Glasgow Outcome Scale (GOS), activities of daily living scale (ADL), and simplified Mini-Mental State Examination (MMSE), and different prognostic analysis methods were performed to determine the prognostic factors of RPD. RESULTS: A total of 149 RPD patients among 15,731 inpatients were identified with an average MMSE value of 13.0 ± 4.6 at baseline. Etiological epidemiology revealed infectious, neurodegenerative and toxic/metabolic diseases as the three largest groups, accounting for 26.2%, 20.8% and 16.8% of all cases, respectively. In particular, prevalence rates of Creutzfeldt-Jakob disease (13.4%), Alzheimer's disease (11.4%), carbon monoxide poisoning (8.1%), neurosyphilis (5.4%) and dementia with Lewy bodies (5.4%) were highest in this series. A recommended diagnostic framework for RPD etiology was thus established. Follow-up evaluations showed a negative correlation between age and GOS scores (r=-0.421, P < 0.001), as well as age and simplified MMSE scores (rs =- 0.393, P < 0.001), and a positive correlation between age and ADL scores (rs =0.503, P < 0.001), and significantly different GOS, ADL and simplified MMSE scores across various etiologies (P = 0.003; F = 9.463, P < 0.001; F = 6.117, P < 0.001). CONCLUSION: Infectious, neurodegenerative and toxic-metabolic entities were the most common RPD categories, and establishing a practical approach to RPD etiology would allow better disease management.
Assuntos
Doença de Alzheimer , Síndrome de Creutzfeldt-Jakob , Humanos , Estudos Retrospectivos , Prevalência , Atividades Cotidianas , Progressão da Doença , Síndrome de Creutzfeldt-Jakob/diagnóstico , Doença de Alzheimer/diagnósticoRESUMO
In this work, a novel bio-based high-performance bisbenzoxazine resin was synthesized from daidzein, 2-thiophenemethylamine and paraformaldehyde. The chemical structure was confirmed using nuclear magnetic resonance spectroscopy (NMR) and Fourier-transform infrared spectroscopy (FT-IR). The polymerization process was systematically studied using differential scanning calorimetry (DSC) and in situ FT-IR spectra. It can be polymerized through multiple polymerization behaviors under the synergistic reaction of thiophene rings with benzopyrone rather than a single polymerization mechanism of traditional benzoxazines, as reported. In addition, thermogravimetric analysis (TGA) and a microscale combustion calorimeter (MCC) were used to study the thermal stability and flame retardancy of the resulting polybenzoxazine. The thermosetting material showed a high carbon residue rate of 62.8% and a low heat release capacity (HRC) value of 33 J/gK without adding any flame retardants. Based on its outstanding capability of carbon formation, this newly obtained benzoxazine resin was carbonized and activated to obtain a porous carbon material doped with both sulfur and nitrogen. The CO2 absorption of the carbon material at 0 °C and 25 °C at 1 bar was 3.64 mmol/g and 3.26 mmol/g, respectively. The above excellent comprehensive properties prove its potential applications in many advanced fields.
Assuntos
Benzoxazinas , Carbono , Benzoxazinas/química , Espectroscopia de Infravermelho com Transformada de Fourier , PolimerizaçãoRESUMO
There is an urgency to produce novel high-performance resins to support the rapid development of the aerospace field and the electronic industry. In the present work, we designed and consequently synthesized a benzoxazine monomer (oHPNI-fa) bearing both norbornene and furan groups through the flexible benzoxazine structural design capability. The molecular structure of oHPNI-fa was verified by the combination characterization of nuclear magnetic resonance spectrum, FT-IR technology, and high-resolution mass spectrum. The thermally activated terpolymerization was monitored by in situ FT-IR as well as differential scanning calorimetry (DSC). Moreover, the low-temperature-curing characteristics of oHPNI-fa have also been revealed and discussed in the current study. Furthermore, the curing kinetics of the oHPNI-fa were investigated by the Kissinger and Ozawa methods. The resulting highly cross-linked thermoset based on oHPNI-fa showed excellent thermal stability as well as flame retardancy (Td10 of 425 °C, THR of 4.9 KJg-1). The strategy for molecular design utilized in the current work gives a guide to the development of high-performance resins which can potentially be applied in the aerospace and electronics industries.
RESUMO
Water oxidation reaction leaves room to be improved in the development of various solar fuel productions, because of the kinetically sluggish 4-electron transfer process of oxygen evolution reaction. In this work, we realize reactive oxygen species (ROS), H2 O2 and OHâ , formations by water oxidation with total Faraday efficiencies of more than 90 % by using inter-facet edge (IFE) rich WO3 arrays in an electrolyte containing CO3 2- . Our results demonstrate that the IFE favors the adsorption of CO3 2- while reducing the adsorption energy of OHâ , as well as suppresses surface hole accumulation by direct 1-electron and indirect 2-electron transfer pathways. Finally, we present selective oxidation of benzyl alcohol by in situ using the formed OHâ , which delivers a benzaldehyde production rate of ≈768â µmol h-1 with near 100 % selectivity. This work offers a promising approach to tune or control the oxidation reaction in an aqueous solar fuel system towards high efficiency and value-added product.
RESUMO
The connectivity of building units for 3D covalent organic frameworks (COFs) has long been primarily 4 and 6, which have severely curtailed the structural diversity of 3D COFs. Here we demonstrate the successful design and synthesis of a porphyrin based, 8-connected building block with cubic configuration, which could be further reticulated into an unprecedented interpenetrated pcb topology by imine condensation with linear amine monomers. This study presents the first case of high-connectivity building units bearing 8-connected cubic nodes, thus greatly enriching the topological possibilities of 3D COFs.