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Mutations in fibrillin 1 (FBN1) is the main cause of Marfan syndrome (MFS) with thoracic aortic aneurysm (TAA) as the main complication. Activation of the complement system plays a key role in the formation of thoracic and abdominal aortic aneurysms. However, the role of the complement system in MFS-associated aortic aneurysms remains unclear. In this study, we observed increased levels of complement C3a and C5a in the plasma of MFS patients and mouse, and the increased deposition of the activated complement system product C3b/iC3b was also observed in the elastic fiber rupture zone of 3-month-old MFS mice. The expression of C3a receptor (C3aR) was increased in MFS aortas, and recombinant C3a promoted the expression of cytokines in macrophages. The administration of a C3aR antagonist (C3aRA) attenuated the development of thoracic aortic aneurysms in MFS mice. The increased inflammation response and matrix metalloproteinases activities were also attenuated by C3aRA treatment in MFS mice. Therefore, these findings indicate that the complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice.
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Adipocinas , Aneurisma da Aorta Torácica , Complemento C3a , Fibrilina-1 , Síndrome de Marfan , Receptores de Complemento , Animais , Feminino , Humanos , Masculino , Camundongos , Adipocinas/genética , Aorta Torácica/patologia , Aneurisma da Aorta Torácica/prevenção & controle , Aneurisma da Aorta Torácica/etiologia , Aneurisma da Aorta Torácica/metabolismo , Aneurisma da Aorta Torácica/patologia , Complemento C3a/antagonistas & inibidores , Complemento C3a/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Fibrilina-1/genética , Mediadores da Inflamação/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Síndrome de Marfan/complicações , Síndrome de Marfan/genética , Síndrome de Marfan/tratamento farmacológico , Camundongos Endogâmicos C57BL , Receptores de Complemento/antagonistas & inibidores , Receptores Acoplados a Proteínas G , Transdução de SinaisRESUMO
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignant tumor worldwide. Considering its special anatomical site and the progressive resistance to chemotherapy drugs, the development of more effective, minimally invasive and precise treatment methods is urgently needed. Nanomaterials, given their special properties, can be used as drug carrier systems to improve the therapeutic effect and reduce the adverse effects. The drug carrier systems with photothermal effect can promote the killing of cancer cells and help overcome drug resistance through heat stress. We selected dopamine, a simple raw material, and designed and synthesized three different configurations of nano-polydopamine (nPDA) nanomaterials, including nPDA balls, nPDA plates and porous nPDA balls. In addition to the self-polymerization and self-assembly, nPDA has high photothermal conversion efficiency and can be easily modified. Moreover, we loaded cisplatin into three different configurations of nPDA, creating nPDA-cis (the nano-drug carrier system with cisplatin), and comparatively studied the properties and antitumor effects of all the nPDA and nPDA-cis materials in vitro and nPDA-cis in vivo. We found that the photothermal effect of the nPDA-cis balls drug carrier system had synergistic effect with cisplatin, resulting in excellent antitumor effect and good clinical application prospects. The comparison of the three different configurations of drug carrier systems suggested the importance of optimizing the spatial configuration design and examining the physical and chemical properties in the future development of nano-drug carrier systems. In this study, we also noted the duality and complexity of the influences of heat stress on tumors in vitro and in vivo. The specific mechanisms and the synergy with chemotherapy and immunotherapy will be an important research direction in the future.
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BACKGROUND General paresis of the insane (GPI) is characterized by cognitive impairment, neuropsychiatric symptoms, and brain structural abnormalities, mimicking many neuropsychiatric diseases. Olfactory dysfunction has been linked to cognitive decline and neuropsychiatric symptoms in numerous neuropsychiatric diseases. Nevertheless, it remains unclear whether patients with GPI experience olfactory dysfunction and whether olfactory dysfunction is associated with their clinical manifestations. MATERIAL AND METHODS Forty patients with GPI and 37 healthy controls (HCs) underwent the "Sniffin Sticks" test battery, Mini-Mental State Examination, and Neuropsychiatric Inventory to measure olfactory function, cognitive function, and neuropsychiatric symptoms, respectively. Brain structural abnormalities were evaluated using visual assessment scales including the medial temporal lobe atrophy (MTA) visual rating scale and Fazekas scale. RESULTS Compared with HCs, patients with GPI exhibited significant olfactory dysfunction, as indicated by deficits in the odor threshold (OT) (P=0.001), odor discrimination (OD) (P<0.001), and odor identification (OI) (P<0.001). In patients with GPI, the OI was positively correlated with cognitive function (r=0.57, P<0.001), but no significant correlation was found between olfactory function and neuropsychiatric symptoms, blood, or cerebrospinal fluid biomarkers (rapid plasma reagin circle card test and Treponema pallidum particle agglutination test), or brain structural abnormalities (MTA and Fazekas scale scores). Mediation analysis indicated that the impaired OI in patients with GPI was mediated by cognitive impairment and impaired OT respectively. CONCLUSIONS Patients with GPI exhibited overall olfactory dysfunction. OI is correlated with cognitive function and the impaired OI is mediated by cognitive impairment in patients with GPI. Thus, OI may serve as a marker for reflecting cognitive function in patients with GPI.
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Disfunção Cognitiva , Transtornos do Olfato , Humanos , Masculino , Disfunção Cognitiva/fisiopatologia , Feminino , Pessoa de Meia-Idade , Transtornos do Olfato/fisiopatologia , Transtornos do Olfato/diagnóstico , Idoso , Testes Neuropsicológicos , Adulto , Biomarcadores , Cognição/fisiologia , Estudos de Casos e Controles , Olfato/fisiologia , Paresia/fisiopatologiaRESUMO
Background: Late-life depression (LLD) is characterized by disrupted brain networks. Resting-state networks in the brain are composed of both stable and transient topological structures known as microstates, which reflect the dynamics of the neural activities. However, the specific pattern of EEG microstate in LLD remains unclear. Methods: Resting-state EEG were recorded for 31 patients with episodic LLD (eLLD), 20 patients with remitted LLD (rLLD) and 32 healthy controls (HCs) using a 64-channel cap. The clinical data of the patients were collected and the 17-Item Hamilton Rating Scale for Depression (HAMD) was used for symptom assessment. Duration, occurrence, time coverage and syntax of the four microstate classes (A-D) were calculated. Group differences in EEG microstates and the relationship between microstates parameters and clinical features were analyzed. Results: Compared with NC and patients with rLLD, patients with eLLD showed increased duration and time coverage of microstate class D. Besides, a decrease in occurrence of microstate C and transition probability between microstate B and C was observed. In addition, the time coverage of microstate D was positively correlated with the total score of HAMD, core symptoms, and miscellaneous items. Conclusion: These findings suggest that disrupted EEG microstates may be associated with the pathophysiology of LLD and may serve as potential state markers for the monitoring of the disease.
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Ovalbumin (OVA) is a major allergen in eggs and could induce severe allergic reactions in sensitive individuals, where the innate immune system works as a regulator. The mechanism of how innate immunity adjusts to food allergy is relatively well-studied, however, the effects of allergen uptake on the innate immune system remain unclear. Therefore, the Caenorhabditis elegans (C. elegans) model was utilized to assess the effects of OVA on its innate immune system. OVA enhanced the immune response of C. elegans with higher survival rates under Pseudomonas aeruginosa infection. Moreover, sustaining OVA treatment improved the health states that were reflected in the prolonged lifespan, alleviated oxidative stress, accelerated growth, and promoted motility. RNA-sequencing analysis and the slow-killing assays in the mutants of insulin/IGF-1 signaling (IIS)-related genes confirmed that IIS was necessary for OVA to regulate innate immunity. Besides, OVA activated SKN-1 temporarily and facilitated the nuclear localization of DAF-16 for improving immunity and health status in C. elegans. Together, OVA could enhance the innate immune responses via DAF-16 and SKN-1 pathways in the IIS of C. elegans, and this work will provide novel insights into the regulation of innate immunity by OVA in higher organisms.
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OBJECTIVE: Cognitive impairments are prevalent in late-life depression (LLD). However, it remains unclear whether there are concurrent brain oscillation alterations in resting condition across varying level of depression severity. This cross-sectional study aims to investigate the characteristics of altered resting-state oscillations, including power spectrum and functional connectivity, and their association with the cognitive impairments in LLD with different depression severity. METHODS: A total of 65 patients with LLD and 40 elder participants without depression were recruited. Global cognition and subtle cognitive domains were evaluated. A five-minute resting-state electroencephalography (EEG) was conducted under eyes-closed conditions. Measurements included the ln-transformed absolute power for power spectrum analysis and the weighted phase lag index (wPLI) for functional connectivity analysis. RESULTS: Attentional and executive dysfunction were exhibited in Moderate-Severe LLD group. Enhanced posterior upper gamma power was observed in both LLD groups. Additionally, enhanced parietal and fronto-parietal/occipital theta connectivity were observed in Moderate-Severe LLD group, which were associated with the attentional impairment. LIMITATIONS: Limitations include a small sample size, concomitant medication use, and a relatively higher proportion of females. CONCLUSIONS: Current study observed aberrant brain activity patterns in LLD across different levels of depression severity, which were linked to cognitive impairments. The altered posterior brain oscillations may be trait marker of LLD. Moreover, cognitive impairments and associated connectivity alterations were exhibited in moderate-severe group, which may be a state-like marker of moderate-to severe LLD. The study deepens understanding of cognitive impairments with the associated oscillation changes, carrying implications for neuromodulation targets in LLD.
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Disfunção Cognitiva , Depressão , Feminino , Humanos , Idoso , Depressão/psicologia , Estudos Transversais , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , EletroencefalografiaRESUMO
Groundwater, the main freshwater resource for humans, has been widely contaminated with nitrate from fertilizers. Here, we report a new and chemical-free strategy to prevent nitrate leaching from soil based on the enrichment of electroactive bacteria, mainly of the genus Geobacter, with bioelectro-barriers, which leads to a nearly 100 % interception of nitrate and partly conserves reactive nitrogen in the form of weakly mobile ammonium by dissimilatory nitrate reduction to ammonium (DNRA). G. sulfurreducens was recognized to efficiently secrete nitrite reductase (NrfA) for rapid DNRA because it lacks nitrate reductase, which inhibits DNRA by competing with nitrite and producing toxic intracellular nitric oxide. With an increase in G. sulfurreducens abundance, near-zero nitrate leaching and 3-fold greater N retention was achieved. Periodic application of weak electricity to the bioelectro-barrier ensured the dominance of G. sulfurreducens in the microbial community and therefore its ability to consistently prevent nitrate leaching. The ability of G. sulfurreducens to intercept nitrate was further demonstrated in more diverse agricultural soils, providing a novel way to prevent nitrate leaching and conserve bioavailable nitrogen in the soil, which has broader implications for both sustainable agriculture and groundwater protection.
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Compostos de Amônio , Água Subterrânea , Humanos , Nitratos/análise , Desnitrificação , Solo , Nitrogênio/análiseRESUMO
BACKGROUND: Patients with atrial fibrillation (AF) and prior stroke history have a high risk of cardiovascular events despite anticoagulation therapy. It is unclear whether catheter ablation (CA) has further benefits in these patients. METHODS: AF patients with a previous history of stroke or systemic embolism (SE) from the prospective Chinese Atrial Fibrillation Registry study between August 2011 and December 2020 were included in the analysis. Patients were matched in a 1:1 ratio to CA or medical treatment (MT) based on propensity score. The primary outcome was a composite of all-cause death or ischemic stroke (IS)/SE. RESULTS: During a total of 4.1 ± 2.3 years of follow-up, the primary outcome occurred in 111 patients in the CA group (3.3 per 100 person-years) and in 229 patients in the MT group (5.7 per 100 person-years). The CA group had a lower risk of the primary outcome compared to the MT group [hazard ratio (HR) = 0.59, 95% CI: 0.47-0.74, P < 0.001]. There was a significant decreasing risk of all-cause mortality (HR = 0.43, 95% CI: 0.31-0.61, P < 0.001), IS/SE (HR = 0.73, 95% CI: 0.54-0.97, P = 0.033), cardiovascular mortality (HR = 0.32, 95% CI: 0.19-0.54, P < 0.001) and AF recurrence (HR = 0.33, 95% CI: 0.30-0.37, P < 0.001) in the CA group compared to that in the MT group. Sensitivity analysis generated consistent results when adjusting for time-dependent usage of anticoagulants. CONCLUSIONS: In AF patients with a prior stroke history, CA was associated with a lower combined risk of all-cause death or IS/SE. Further clinical trials are warranted to confirm the benefits of CA in these patients.
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BACKGROUND: Due to the anatomically adjacent relationship between the left atrium (LA) and esophagus, energy delivery on the posterior wall of LA is limited. The aim of this study was to evaluate the feasibility of a novel esophageal retractor (SAFER) with an inflatable C-curve balloon during atrial fibrillation (AF) ablation. METHOD: Nine patients underwent AF ablation assisted with the SAFER. After inflation, the esophagus was deviated laterally away from the intended ablation site of the posterior wall under local anesthesia. The extent of mechanical esophageal deviation (MED) was evaluated under fluoroscopy, defined as the shortest distance from the trailing esophageal edge to the closest point of the ablation line. Gastroscopy was performed before and after ablation. The target ablation index used in all LA sites including the posterior wall was 400-450 after effective MED. All adverse events during the periprocedural period were recorded. RESULTS: The mean deviation distance achieved 16.2 ± 9.6 mm away from the closest ablation point of the pulmonary vein lesion set. With respect to the individual left and right pulmonary vein lesion sets, the deviation distance was 19.7 ± 11.5 and 12.7 ± 6.8 mm, respectively. The extent of deviation was 0 to 5 mm, 5.1 to 10 mm, or >10 mm in 0(0%), 7(38.9%), and 11(61.1%), respectively. Procedural success was achieved in all patients without acute reconnection. There was only one esophageal complication which manifested as esophageal erosion and this patient experienced throat pain possibly related to the SAFER retractor with no clinical sequelae. CONCLUSION: Esophageal deviation with the novel eccentric balloon is a novel feasible choice during AF ablation, enabling adequate energy delivery to the posterior wall of LA. Additional prospective randomized controlled studies are required for further validation.
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Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Humanos , Estudos Prospectivos , Esôfago , Átrios do Coração , Fluoroscopia , Ablação por Cateter/métodos , Veias Pulmonares/cirurgiaRESUMO
Aqueous zinc ion batteries (AZIBs) are promising electrochemical energy storage devices due to their high theoretical specific capacity, low cost, and environmental friendliness. However, uncontrolled dendrite growth poses a serious threat to the reversibility of Zn plating/stripping, which impacts the stability of batteries. Therefore, controlling the disordered dendrite growth remains a considerable challenge in the development of AZIBs. Herein, a ZIF-8-derived ZnO/C/N composite (ZOCC) interface layer was constructed on the surface of the Zn anode. The homogeneous distribution of zincophilic ZnO and the N element in the ZOCC facilitates directional Zn deposition on the (002) crystal plane. Moreover, the conductive skeleton with a microporous structure accelerates Zn2+ transport kinetics, resulting in a reduction in polarization. As a result, the stability and electrochemical properties of AZIBs are improved. Specifically, the ZOCC@Zn symmetric cell sustains over 1150 h at 0.5 mA cm-2 with 0.25 mA h cm-2, while the ZOCC@Zn half-cell achieves an outstanding Coulombic efficiency of 99.79% over 2000 cycles. This work provides a simple and effective strategy for improving the lifespan of AZIBs.
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Based on the dual-resonance principle around the dispersion turning point, a scheme of chiral long-period fiber gratings (CLPGs) formed by twisting a high-birefringence (Hi-Bi) fiber is herein proposed to realise ultra-broadband flat-top circular polarizers. The coupling bandwidth is approximately seven times larger than that of traditional CLPGs. In addition, by introducing chirp characteristics in these CLPGs, an ultra-broadband flat-top circular polarizer with â¼200â nm@3â dB was conveniently achieved. Subsequently, by optimising the chirped CLPGs, a circular polarizer with a bandwidth extinction ratio of approximately 30â dB and a high level of â¼100â nm at 1â dB was realised. It was shown that the mode-controlling performances of the CLPGs can be remarkably improved, which has significant applications in light-field regulation. Finally, for the first time, it was proved that the CLPG cannot generate a vortex beam.
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The pseudocapacitor material is easily decomposed when immersed in alkaline solution for a long time. Hence, it is necessary to find a strategy to improve the alkali stability of pseudocapacitor materials. In addition, the relationship between alkali stability and electrochemical performance is still unclear. In this work, a series of Al-based LDH (Layered double hydroxide) and derived Ni/Co-based sulfides are prepared, and corresponding alkali stability and electrochemical performance are analyzed. The alkali stability of CoAl LDH is so poor and can be improved effectively by doping of Ni. Ni1Co2S4 and Ni2Co1Al LDH exhibit an outstanding alkali stability, and Ni2Co1S4 exhibits an extremely poor alkali stability. The variable valence state of Co element and the solubility of Al in alkali solution are the fundamental reasons for the poor alkali stability of CoAl LDH and Ni2Co1S4. Ni2Co1S4 showed an outstanding electrochemical performance in a three-electrode system, which is better than that of Ni1Co2S4, indicating that there is no direct correlation between alkali stability and electrochemical properties. Sulfidation improved the electrical conductivity and electrochemical activity of electrode materials, whereas alkali etching suppressed the occurrence of the electrochemical reaction. Overall, this work provides a clear perspective to understand the relationship between alkali stability and electrochemical properties.
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Álcalis , Hidróxidos , Cobalto/química , Hidróxidos/química , SulfetosRESUMO
Reasonable structural design and composition control are the dominant factors for tuning the electromagnetic absorbing properties of materials. In this paper, microspheres composed of NiO, Ni, and Co3O4 nanoparticles (NCMO) were successfully synthesized using a mild oxidation method. Benefiting from the multi-component composition and a unique microstructure, the RLmin of CNMO can reach -46.8 dB at 17 GHz, with an effective absorption bandwidth of 4.1 GHz (13.9-18 GHz). The absorbing properties and the absorbing mechanism analysis showed that the microsphere-structured NCMO composed of multi-component nanoparticles enhanced the interface polarization, thereby improving the absorption performance. This research provides a new avenue for MOF-derived oxide materials with excellent electromagnetic wave absorbing properties.
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Considering the electromagnetic protection needs of important ground buildings, exploring the electromagnetic wave (EMW) absorption performance of manganese ore powder (MOP) building materials is an effective way to overcome its low added value and difficulty in popularizing. Here, choosing filling ratios commonly used in building materials such as autoclaved bricks, MOP/paraffin samples with 20%, 40%, and 60% mass fraction of MOP were prepared, and electromagnetic properties were analyzed at 2−18 GHz using the coaxial method. The results show that 60 wt% sample has the best absorption performance, with a minimum reflection loss (RLmin) value of −22.06 dB at 15.04 GHz, and the effective absorption bandwidth (EAB, RL < −10 dB) reaches 4.16 GHz at a 7.65 mm absorber thickness, covering most of the Ku-band region. The excellent microwave absorption performance of MOP is due to its multi-oxide forming multi-interface structure and rough surface, which can not only form abundant dipole and interfacial polarization under the action of EMW, but also reflect and scatter the incident EMW, prolong the transmission path, and enhanced the absorption of microwaves. This study demonstrates that MOP building materials can have excellent microwave absorption properties, thus becoming a new way to address harmful manganese residue; for example, autoclaved bricks, which can not only improve the added value of manganese residue building materials but also can be consumed on a large scale. It provides a new idea to solve the harm of manganese residue.
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Manganês , Micro-Ondas , Pós , Dióxido de SilícioRESUMO
The porous and biomimetic cobalt silicate@diatomite (Co2SiO4@diatomite) was successfully synthesized by a two-step method, including the hydrothermal method and calcination to improve the electromagnetic wave absorption property. Different hydrothermal times were well-tuned for Co2SiO4@diatomite composites with different loadings of Co2SiO4. Interestingly, the Co2SiO4@diatomite composites (6 h, 25 wt%) had a smaller minimum reflection loss. Moreover, the minimum reflection loss (RLmin) could reach -12.03 dB at 16.64 GHz and the matched absorber thickness was 10 mm, while the effective absorption bandwidth (EAB, RL ≤ -10 dB) could be 1.92 GHz. In principle, such findings indicate that Co2SiO4@diatomite nanocomposites could be a promising candidate for high-efficiency microwave absorption capability.
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Recently, the development of composite materials composed of magnetic materials and MXene has attracted significant attention. However, the thickness and microwave absorption performance of the composite is still barely satisfactory. In this work, the C-N@NiFe2O4@MXene/Ni nanocomposites were successfully synthesized in situ by hydrothermal and calcination methods. Benefiting from the introduction of the carbon-nitrogen(C-N) network structure, the overall dielectric properties are improved effectively, consequently reducing the thickness of the composite while maintaining excellent absorption performance. As a result, the minimum reflection loss of C-N@NiFe2O4@MXene/Ni can reach -50.51 dB at 17.3 GHz at an ultralow thickness of 1.5 mm, with an effective absorption bandwidth of 4.95 GHz (13.02-18 GHz). This research provides a novel strategy for materials to maintain good absorption performance at an ultralow thickness level.
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Based on their characteristics, transition metal layered double hydroxides have been of great scientific interest for their use in supercapacitors. Up until now, severe aggregation and low intrinsic conductivity have been the major hurdles for their application. In this work, nickel-iron sulfide nanosheets (NiFeSx) and carbon nanotubes (CNTs) were synthesized on diatomite using chemical vapor deposition and a two-step hydrothermal method to overcome these challenges. Synthesis of this composite successfully exploits the synergistic effect of multicomponent materials to improve the electrochemical performance. Diatomite is selected as a substrate to provide preferable surroundings for the uniform dispersion of nanomaterial on its surface, which enlarges the active sites that come in contact with the electrolytes, significantly improving the electrochemical properties. Combined with high conductivity and a synchronous sulfurization effect, the NiFeSx@CNTs@MnS@Diatomite electrode delivered a high specific capacitance of 552F g-1 at a current density of 1 A g-1, a good rate capability of 68.4% retention at 10 A g-1, and superior cycling stability of 89.8% capacitance retention after 5000 cycles at 5 A g-1. Furthermore, an asymmetric supercapacitor assembled via NiFeSx@CNTs@MnS@Diatomite and graphene delivered a maximum energy density of 28.9 Wh kg-1 and a maximum power density of 9375 W kg-1 at a potential of 1.5 V. This research lays the groundwork for ideal material preparation as well as a rational design for the electrode material, including property enhancement of diatomite-based material for use in supercapacitors.
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In this work, spherical flower-shaped composite carbonyl iron powder@MnO2 (CIP@MnO2) with CIP as the core and ultrathin MnO2 nanosheets as the shell was successfully prepared by a simple redox reaction to improve oxidation resistance and electromagnetic wave absorption properties. The microwave-absorbing properties of CIP@MnO2 composites with different filling ratios (mass fractions of 20%, 40%, and 60% after mixing with paraffin) were tested and analyzed. The experimental results show that compared with pure CIP, the CIP@MnO2 composites have smaller minimum reflection loss and a wider effective absorption bandwidth than CIP (RL < -20 dB). The sample filled with 40 wt% has the best comprehensive performance, the minimum reflection loss is -63.87 dB at 6.32 GHz, and the effective absorption bandwidth (RL < -20 dB) reaches 7.28 GHz in the range of 5.92 GHz-9.28 GHz and 11.2 GHz-15.12 GHz, which covers most C and X bands. Such excellent microwave absorption performance of the spherical flower-like CIP@MnO2 composites is attributed to the combined effect of multiple beneficial components and the electromagnetic attenuation ability generated by the special spherical flower-like structure. Furthermore, this spherical flower-like core-shell shape aids in the creation of discontinuous networks, which improve microwave incidence dispersion, polarize more interfacial charges, and allow electromagnetic wave absorption. In theory, this research could lead to a simple and efficient process for producing spherical flower-shaped CIP@MnO2 composites with high absorption, a wide band, and oxidation resistance for a wide range of applications.
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Oxide-/hydroxide-derived copper electrodes exhibit excellent selectivity toward C2+ products during the electrocatalytic CO2 reduction reaction (CO2RR). However, the origin of such enhanced selectivity remains controversial. Here, we prepared two Cu-based electrodes with mixed oxidation states, namely, HQ-Cu (containing Cu, Cu2O, CuO) and AN-Cu (containing Cu, Cu(OH)2). We extracted an ultrathin specimen from the electrodes using a focused ion beam to investigate the distribution and evolution of various Cu species by electron microscopy and electron energy loss spectroscopy. We found that at the steady stage of the CO2RR, the electrodes have all been reduced to Cu0, regardless of the initial states, suggesting that the high C2+ selectivities are not associated with specific oxidation states of Cu. We verified this conclusion by control experiments in which HQ-Cu and AN-Cu were pretreated to fully reduce oxides/hydroxides to Cu0, and the pretreated electrodes showed even higher C2+ selectivity compared with their unpretreated counterparts. We observed that the oxide/hydroxide crystals in HQ-Cu and AN-Cu were fragmented into nanosized irregular Cu grains under the applied negative potentials. Such a fragmentation process, which is the consequence of an oxidation-reduction cycle and does not occur in electropolished Cu, not only built an intricate network of grain boundaries but also exposed a variety of high-index facets. These two features greatly facilitated the C-C coupling, thus accounting for the enhanced C2+ selectivity. Our work demonstrates that the use of advanced characterization techniques enables investigating the structural and chemical states of electrodes in unprecedented detail to gain new insights into a widely studied system.
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A novel tetraphenylethylene-based ladder network (MP1) made by polycondensation reaction from 4,4',4â³,4â´-(ethene-1,1,2,2-tetrayl)tetrakis(benzene-1,2-diol) and 2,3,5,6-tetrafluoroterephthalonitrile and its COOH-functionalized analogue (MP2) were synthesized for the first time. Their structures were confirmed by solid-state nuclear magnetic resonance (13C cross-polarization magic angle spinning), Fourier transform infrared spectroscopy, and elementary analysis. MP1 exhibited a high Brunauer-Emmett-Teller surface area (1020 m2 g-1), whereas the COOH-functionalized MP2 showed a much smaller surface area (150 m2 g-1) but displayed a more uniform pore size distribution. Because of the high density of nitrile groups in the network polymers of intrinsic microporosity (PIMs) and strong interaction with quadrupole CO2 molecules, MP1 exhibited a high CO2 adsorption capacity of 4.2 mmol g-1 at 273 K, combined with an isosteric heat of adsorption (Q st) of 29.6 kJ mol-1. The COOH-functionalized MP2 showed higher Q st of 34.2 kJ mol-1 coupled with a modest CO2 adsorption capacity of 2.2 mmol g-1. Both network PIMs displayed high theoretical ideal adsorbed solution theory CO2/N2 selectivities (51 and 94 at 273 K vs 34 and 84 at 298 K for MP1 and MP2, respectively). The high selectivities of MP1 and MP2 were confirmed by experimental column breakthrough experiments with CO2/N2 selectivity values of 23 and 45, respectively. Besides the promising CO2 capture and CO2/N2 selectivity properties, MP1 also demonstrated high sorption capacity for toxic volatile organic vapors. At 298 K and a relative pressure of 0.95, benzene and toluene sorption uptakes reached 765 and 1041 mg g-1, respectively. Moreover, MP1 also demonstrated some potential for adsorptive separation of xylene isomers with adsorptive selectivity of 1.75 for m-xylene/o-xylene.