The development of solvent‐free, metal‐free, recyclable organic catalysts is required for the current chemical fixation of carbon dioxide converted into cyclic carbonates. With the goal of reducing ...the cost, time, and energy consumption for the coupling reaction of CO2 and epoxides, a series of highly active heterogeneous catalysts, based on a thiourea and quaternary ammonium salt system, are synthesized by using a thiol‐ene click reaction under ultraviolet light. Benefitting from synergistic interactions of the electrophilic center (thiourea) and the nucleophilic site (ammonium bromide), the catalysts exhibit excellent catalytic selectivity (99 %) for the cycloaddition of carbon dioxide with a diverse range of epoxides under mild conditions (1.2 MPa, 100 °C). Moreover, the catalyst can be easily recycled by facile filtration and reused for 5 times without noticeable loss of activity and selectivity. This work provides a potential heterogeneous catalyst for the conversion of carbon dioxide into high value‐added chemicals with the combined advantages of low cost, easy recovery, and satisfactory catalytic properties.
Resins to be cheerful: A series of heterogeneous bifunctional catalysts, based on a thiourea and quaternary ammonium salt system, is prepared by using a convenient and low‐cost method involving a thiol‐ene click reaction under ultraviolet light. Owing to synergistic interactions of the electrophilic center and the nucleophilic site, the catalysts exhibit excellent selectivity for the cycloaddition of carbon dioxide with a diverse range of epoxides under mild conditions.
Background
The prognostic significance of hyperperfusion after reperfusion therapy in patients with acute ischemic stroke (AIS) remains controversial.
Purpose
To investigate the clinical factors ...associated with hyperperfusion, and the 90‐day prognostic value of hyperperfusion after mechanical thrombectomy in AIS patients.
Study Type
Retrospective.
Population/Subjects
Fifty‐four AIS patients who underwent mechanical thrombectomy.
Field Strength/Sequence
Time‐of‐flight MR angiography, pulsed arterial spin labeling (ASL), diffusion‐weighted imaging (DWI), and susceptibility‐weighted imaging were performed at 3.0T within 1 week after thrombectomy.
Assessment
Clinical factors including demographics, risk factors, stroke and treatment characteristics were collected and assessed. Hyperperfusion on ASL was defined as a focal increased cerebral blood flow on the affected side ≥130% of its mirror counterpart. Good clinical outcome at 90 days was defined as modified Rankin Scale score of 0–2.
Statistical Tests
The interrater agreement was assessed using Cohen's kappa or the intraclass correlation coefficient. The relationship between hyperperfusion and clinical factors were analyzed by appropriate univariate statistics. Predictors of 90‐day functional outcome were assessed by univariate analyses followed by multivariate logistic regression analysis and receiver‐operating‐characteristic curves.
Results
Thirty‐six (66.7%) patients developed hyperperfusion on ASL after thrombectomy. Hyperperfusion was significantly correlated with successful recanalization (P < 0.05) and improvement of National Institutes of Health Stroke Scale scores at 24 hours (NIHSS24h) (P < 0.05). A higher incidence of hemorrhage transformation was observed in patients with hyperperfusion than those without (63.9% vs. 50.0%), but no significant difference was found (P = 0.327). NIHSS24h (odds ratio OR, 0.75, 95% confidence interval CI 0.62–0.91, P < 0.05), lesion volume on diffusion‐weighted imaging (OR, 0.97, 95% CI 0.95–1.00, P < 0.05), and hyperperfusion on ASL (OR, 9.8, 95% CI 1.7–55.3, P < 0.05) were independent variables for predicting good functional outcomes.
Data Conclusion
Hyperperfusion on ASL correlated with successful recanalization and may be an independent prognostic marker for good neurological outcomes at 90 days in AIS patients after mechanical thrombectomy.
Level of Evidence
4
Technical Efficacy Stage
2
LiNi0.8Co0.15Al0.05O2 (NCA), a cathode material for lithium-ion batteries (LIBs), is a promising material due to its high specific capacity. However, there are drawbacks like high cost, safety ...issues, and limited cycle-performance that represent obstacles for commercial applications. This study describes a simple ballmilling method to modify the surface of NCA materials and fill the gaps between particles by LiFePO4 (LFP) cathode to improve its charge/discharge rate. The results show that NCA@5LFP, mixed with 5 wt % LFP, has the best cycling and rate performance, with a higher capacity-retention (89.4% after 200 cycles, at 2C). Post-electrochemical and in-situ analysis reveal more detailed reasons of the observed improvements. The formation of a more stable solid electrolyte interface film in the NCA@5LFP hybrid electrode helps ensure the orderliness of the NCA structure, by reducing the charge-transfer resistance, and increasing the channel for lithium ion de-intercalation. All these factors help improve the battery performance.
•Improved charge/discharge rate via NCA@LFP mixed electrode by simple ball-milling.•In-situ XRD reveals evolution of NCA@5LFP electrode structure.•Post-electrochemical TEM and XPS reveal interface structure and element distribution.
This study aimed to establish the role of miR-129 and miR-384-5p in cerebral ischemia-induced apoptosis. Using PC12 cells transfected with miR-129 or miR-384-5p mimics or inhibitors, oxygen glucose ...deprivation (OGD) conditions were applied for 4 h to simulate transient cerebral ischemia. Apoptotic phenotypes were assessed via lactate dehydrogenase (LDH) assay, MTT cell metabolism assay, and fluorescence-activated cell sorting (FACS). The effect of miR overexpression and inhibition was evaluated by protein and mRNA detection of bcl-2 and caspase-3, critical apoptosis factors. Finally, the direct relationship of miR-129 and bcl-2 and miR-384-5p and caspase-3 was measured by luciferase reporter assay. The overexpression of miR-384-5p and miR-129 deficiency significantly enhanced cell viability, reduced LDH release, and inhibited apoptosis. By contrast, overexpression of miR-129 and miR-384-5p deficiency aggravated hypoxia-induced apoptosis and cell injury. miR-129 overexpression significantly reduced mRNA and protein levels of bcl-2 and miR-129 inhibition significantly increased mRNA and protein levels of bcl-2 in hypoxic cells.miR-384-5p overexpression significantly reduced protein levels of caspase-3 while miR-384-5p deficiency significantly increased protein levels of caspase-3. However, no changes were observed in caspase-3 mRNA in either transfection paradigm. Finally, luciferase reporter assay confirmed caspase-3 to be a direct target of miR-384-5p; however, no binding activity was detected between bcl-2 and miR-129.Transient cerebral ischemia induces differential expression of miR-129 and miR-384-5p which influences apoptosis by regulating apoptotic factors caspase-3 and bcl-2, thereby participating in the pathological mechanism of cerebral ischemia, and becoming potential targets for the treatment of ischemic cerebral injury in the future.
Graphic abstract
CD58 and CD2 have long been known as a pair of reciprocal adhesion molecules involved in the immune modulations of CD8
T and NK-mediated cellular immunity in humans and several other mammals. ...However, the functional roles of CD58 and CD2 in CD4
T-mediated adaptive humoral immunity remain poorly defined. Moreover, the current functional observations of CD58 and CD2 were mainly acquired from
assays, and
investigation is greatly limited due to the absence of a
homology in murine models. In this study, we identified
and
homologs from the model species zebrafish (
). These two molecules share conserved structural features to their mammalian counterparts. Functionally,
and
were significantly upregulated on antigen-presenting cells and Cd4
T cells upon antigen stimulation. Blockade or knockdown of Cd58 and Cd2 dramatically impaired the activation of antigen-specific Cd4
T and mIgM
B cells, followed by the inhibition of antibody production and host defense against bacterial infections. These results indicate that CD58/CD2 interaction was required for the full activation of CD4
T-mediated adaptive humoral immunity. The interaction of Cd58 with Cd2 was confirmed by co-immunoprecipitation and functional competitive assays by introducing a soluble Cd2 protein. This study highlights a new costimulatory mechanism underlying the regulatory network of adaptive immunity and makes zebrafish an attractive model organism for the investigation of CD58/CD2-mediated immunology and disorders. It also provides a cross-species understanding of the evolutionary history of costimulatory signals from fish to mammals as a whole.
It is recognized that the cerebral ischemia/reperfusion (I/R) injury triggers inflammatory activation of microglia and supports microglia-driven neuronal damage. Our previous studies have shown that ...ginsenoside Rg1 had a significant protective effect on focal cerebral I/R injury in middle cerebral artery occlusion (MCAO) rats. However, the mechanism still needs further clarification. Here, we firstly reported that ginsenoside Rg1 effectively suppressed the inflammatory activation of brain microglia cells under I/R conditions depending on the inhibition of Toll-likereceptor4 (TLR4) proteins. In vivo experiments showed that the ginsenoside Rg1 administration could significantly improve the cognitive function of MCAO rats, and in vitro experimental data showed that ginsenoside Rg1 significantly alleviated neuronal damage via inhibiting the inflammatory response in microglia cells co-cultured under oxygen and glucose deprivation/reoxygenation (OGD/R) condition in gradient dependent. The mechanism study showed that the effect of ginsenoside Rg1 depends on the suppression of TLR4/MyD88/NF-κB and TLR4/TRIF/IRF-3 pathways in microglia cells. In a word, our research shows that ginsenoside Rg1 has great application potential in attenuating the cerebral I/R injury by targeting TLR4 protein in the microglia cells.
A radialized nanostructure catalyst self-assembled by MnOOH/MnO2 nanosheets anchored with Pt single atoms (PtSA-MnOOH/MnO2) is developed by thermally assisted two-step electrochemical method. It ...implements real-time HCHO-to-CO2 conversion (∼85.7%) and long-term continuous HCHO removal (∼98%) for 100 h in 15 ppm HCHO atmosphere at 25 °C at the first time, by the collaborative action of active hydroxyl and active oxygen species.
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•PtSA-MnOOH/MnO2 catalyst is developed by thermally assisted two-step electrodeposition.•The catalyst shows the unique 3D radialized nanostructure.•It implements enhanced HCHO-to-CO2 conversion (∼85.7%) in 15 ppm HCHO atmosphere at 25 °C.•In the dynamic test, the catalyst achieves long-term continuous HCHO removal (∼98%) for 100 h.•The synergistic action between PtSA (O*) and MnOOH (OH*) for enhancing CO2 conversion in indoor formaldehyde degradation.
Maintaining high activity during prolonged catalysis is always the pursuit in catalytic degradation of organic pollutants. For indoor formaldehyde (HCHO) degradation, the accumulation of intermediates is the major factor limiting the conversion of HCHO to final product CO2 (HCHO-to-CO2 conversion) and long-lasting catalysis. Herein, a three-dimensional radialized nanostructure catalyst self-assembled by MnOOH/MnO2 nanosheets anchored with Pt single atoms (PtSA-MnOOH/MnO2 with a trace platinum loading amount of 0.09%) is developed by thermally assisted two-step electrochemical method, which achieves enhanced CO2 production in catalytic HCHO degradation at the room temperature by the collaborative action of active hydroxyl (OH*) and active oxygen species (O2*). By boosting intermediates’ decomposing, the catalyst implements real-time HCHO-to-CO2 conversion (∼85.7%) and long-term continuous HCHO removal (∼98%) during 100 h in a 15 ppm HCHO atmosphere at 25 °C under a weight hourly space velocity of 30000 mL/gcat∙h. Density functional theory calculation shows that the formation energy of O2* from O2 over PtSA-MnOOH/MnO2 is nearly half lower than that over Pt-MnO2 catalyst. And decomposing accumulated intermediates gives the credit to OH* species sustainably generated by the combined action of MnOOH and O2*. The synergistic action between PtSA and MnOOH contributes to the continuous production of O2* and OH* for enhancing CO2 production in indoor catalytic formaldehyde degradation.
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•A self-powered triboelectric catalyst is prepared by electrostatic spinning.•The triboelectric catalysts promote the generation of reactive oxygen species.•Triboelectric charges ...promote the continuous decomposition of intermediate products.•The CO2 production efficiency can be improved to78.93%.
The accumulation of intermediates is an important reason for the inactivation of many catalysts including formaldehyde (HCHO) degradation materials. Herein, self-powered triboelectric catalysts (MnOx-PMMA-SSM) with a three-dimensional nanocomposite structure self-assembled by nanoflowered MnOx inlaid porous polymethyl methacrylate (PMMA) nanofibers based on stainless steel mesh (SSM) substrate, is fabricated by electrostatic spinning and hydrolysis methods. The self-powered triboelectric catalysts can promote the generation of reactive oxygen species (O*) under the action of triboelectric charges from the friction between PMMA fibers and SSM driven by the wind, thus promoting the catalytic oxidation of HCHO and intermediates. In the 15 ppm HCHO atmosphere, the CO2 production efficiency for the self-powered triboelectric catalysts can improve 36.25% up to78.93% compared with traditional MnOx catalysts, and the catalyst life is as high as 72 h without evident decay. This research provides a new strategy for high-efficiency, long-term and zero-energy degradation HCHO at room temperature.
Objective
To compare the prognostic value of net water uptake (NWU) and target mismatch (TM) on CT perfusion (CTP) in acute ischemic stroke (AIS) patients with late time window.
Methods
One hundred ...and nine consecutive AIS patients with anterior-circulation large vessel occlusion presenting within 6–24 h from onset/last seen well were enrolled. Automated Alberta Stroke Program Early CT Score–based NWU (ASPECTS-NWU) was calculated from admission CT. The correlation between ASPECTS-NWU and CTP parameters was assessed. Predictors for favorable outcome (modified Rankin Scale score ≤ 2) at 90 days were assessed using logistic regression analysis. The ability of outcome prediction between ASPECTS-NWU and TM (an ischemic core < 70 mL, a mismatch ratio ≥ 1.8, and an absolute difference ≥ 15 mL) was compared using receiver operating characteristic (ROC) curve.
Results
A higher level of ASPECTS-NWU was associated with a larger ischemic core (
r
= 0.66,
p
< 0.001) and a larger hypoperfusion volume (
r
= 0.38,
p
< 0.001). ASPECTS-NWU performed better than TM for outcome stratification (area under the curve AUC, 0.738 vs 0.583,
p
= 0.004) and was the only independent neuroimaging marker associated with favorable outcomes compared with CTP parameters (odds ratio, 0.73; 95% confidence interval CI 0.62–0.87,
p
< 0.001). An outcome prediction model including ASPECTS-NWU and clinical variables (National Institutes of Health Stroke Scale scores and age) yielded an AUC of 0.828 (95% CI 0.744–0.893; sensitivity 65.4%; specificity 87.7%).
Conclusion
ASPECTS-NWU performed better than TM for outcome prediction in AIS patients with late time window and might be an alternative imaging biomarker to CTP for patient selection.
Clinical relevance statement
Automated Alberta Stroke Program Early CT Score–based net water uptake outperforms target mismatch on CT perfusion for the outcome prediction in patients with acute ischemic stroke and can be an alternative imaging biomarker for patient selection in late therapeutic window.
Key Points
• A higher ASPECTS-based net water uptake was associated with larger ischemic cores and hypoperfusion volumes on CT perfusion.
• ASPECTS-based net water uptake outperformed target mismatch for outcome prediction in acute ischemic stroke with extended therapeutic window.
• ASPECTS-based net water uptake can be an alternative biomarker to target mismatch for selecting acute ischemic stroke patients with late therapeutic window.
•Anion assisted completely reconfigured MnOx electrocatalysts was prepared.•The optimal H+ adsorption can be achieved by anion-assisted complete reconfiguration.•Reconfiguration can enhance charge ...transport and intrinsic activity of the catalyst.•The R-S-MnOx-CC catalyst has excellent acidic HER performance in acidic media.
The optimal proton adsorption design of non-noble metal based catalysts is critical to the realization of efficient hydrogen evolution reactions (HER) in acidic media, but it is also challenging. Herein, sulfur anion-assisted completely reconfigured MnOx (R-S-MnOx-CC) with self-supported nanostructure was prepared on carbon cloth by in situ phase transformation method. The reconfiguration process results in spinel-structured Mn3O4 which can enhance charge transport and expose more active sites through charge disproportionation. The theoretical calculation indicates that the reconfiguration can increase the electron state density of the Mn d band near the Fermi level, promote the right shift of the d-band center, enhance the electron transport capacity of the catalyst to achieve the optimal H+ adsorption. The R-S-MnOx-CC catalyst has excellent acidic HER performance with an overpotential of only 43 mV and 234 mV at 10 mA cm−2 and 400 mA cm−2, respectively, a low charge transfer resistance Rct (0.29 Ω) and stably maintained for 100 h without decay (∼300 mA cm−2). This strategy provides a feasible way to design efficient and stable non-noble metal-based electrocatalysts for the HER industrialization of proton exchange membrane (PEM) water electrolyzers.
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