Electrospun carbonaceous fibers have emerged as promising electrode materials for application in energy storage devices. However, their relatively poor electrical conductivity (due to their amorphous ...carbon structures) and low capacitive performance lead to poor prospects for their further application. Herein, a universal synthesis of highly graphitized carbon nanofibers, containing various metal oxide nanoparticles (e.g., Fe2O3, NiO), by the pyrolysis of metal–organic framework (MOF)‐embedded electrospun nanofibers, is reported. The resulting carbon nanofibers exhibit large mesopore volumes, contain large quantities of Faradic metal oxide nanoparticles, and are highly graphitized. The fibers also have excellent mechanical flexibility, provide fast ion transfer characteristics, and a large pseudocapacitance combined with excellent electrical conductivity, leading to large specific capacitances. Consequently, asymmetric flexible hybrid supercapacitors assembled from Fe2O3‐embedded highly graphitized carbon nanofibers (FOCNF) and NiO‐embedded highly graphitized carbon nanofibers (NOCNF) exhibit a high energy density of 43.1 Wh kg−1 at a power density of 412.5 W kg−1 and possess excellent flexibility (capacitance retention of 94.4% at 180° bending and 96.2% at 30° twisting) with superior cycling stability. This strategy provides a new MOF‐based approach for the design and synthesis of multifunctional flexible carbonaceous materials and might lead to their further application in flexible energy storage devices.
Highly graphitized carbon nanofibers with metal oxide nanoparticles are synthesized based on the metal–organic framework‐based electrospinning approach. The representative examples with Fe2O3 and NiO nanoparticles demonstrate high electrochemical performances, showing potential application as active materials for flexible hybrid supercapacitors.
Abstract Recent data indicates that DJ-1 plays a role in the cellular response to stress. Here, we aimed to examine the underlying molecular mechanisms mediating the actions of DJ-1 in the heart ...following myocardial ischemia–reperfusion (I/R) injury. In response to I/R injury, DJ-1 KO mice displayed increased areas of infarction and worsened left ventricular function when compared to WT mice, confirming a protective role for DJ-1 in the heart. In an effort to evaluate the potential mechanism(s) responsible for the increased injury in DJ-1 KO mice, we focused on SUMOylation, a post-translational modification process that regulates various aspects of protein function. DJ-1 KO hearts after I/R injury were found to display enhanced accumulation of SUMO-1 modified proteins and reduced SUMO-2/3 modified proteins. Further analysis, revealed that the protein expression of the de-SUMOylation enzyme SENP1 was reduced, whereas the expression of SENP5 was enhanced in DJ-1 KO hearts after I/R injury. Finally, DJ-1 KO hearts were found to display enhanced SUMO-1 modification of dynamin-related protein 1, excessive mitochondrial fission, and dysfunctional mitochondria. Our data demonstrates that the activation of DJ-1 in response to myocardial I/R injury protects the heart by regulating the SUMOylation status of Drp1 and attenuating excessive mitochondrial fission.
The rate and extent of enzymatic hydrolysis of lignocellulosic biomass highly depend on enzyme loadings, hydrolysis periods, and structural features resulting from pretreatments. Furthermore, the ...influence of one structural feature on biomass digestibility varies with the changes in enzyme loading, hydrolysis period and other structural features as well. In this paper, the effects of lignin content, acetyl content, and biomass crystallinity on the 1-, 6-, and 72-h digestibilities with various enzyme loadings were investigated. To eliminate the cross effects among structural features, selective pretreatment techniques were employed to vary one particular structural feature during a pretreatment, while the other two structural features remained unchanged. The digestibility results showed that lignin content and biomass crystallinity dominated digestibility whereas acetyl content had a lesser effect. Lignin removal greatly enhanced the ultimate hydrolysis extent. Crystallinity reduction, however, tremendously increased the initial hydrolysis rate and reduced the hydrolysis time or the amount of enzyme required to attain high digestibility. To some extent, the effects of structural features on digestibility were interrelated. At short hydrolysis periods, lignin content was not important to digestibility when crystallinity was low. Similarly, at long hydrolysis periods, crystallinity was not important to digestibility when lignin content was low.
•Emerging strategies for electrochemical nanoarchitectonic are extensively reviewed.•Applications to capacitors, electrochromism, sensing, corrosion, water splitting.•Fundamental electrochemistry on ...nanoarchitectonic-based LbL films is reviewed.•A special emphasis has been put on electroclick and carbazole chemistry approaches.•Applications for patterning, solar cells and biofunctional surfaces are summarized.
During the last few decades, electrochemistry and electrode modification have seen a tremendous fall off in creativity with the emergence of the nanoarchitectonic-based layer-by-layer (LbL) film deposition technique. An unprecedented variety of building blocks can be immobilized on surfaces, leading to progress in several fields including sensing, electrochromic, electro-responsive and energy devices. This review describes the state of the art of electrochemical devices based on LbL assemblies, with a focus on supercapacitors, biosensors, and electroresponsive LbL such as electrodissolution/electroswelling of coatings. Recently, electrochemistry has also been used as an “active trigger” to induce the formation of films by covalent coupling, leading to new nanoarchitectonic approaches beyond the LbL strategy. These emerging electro-coupling reactions, including electroclick and carbazole chemistry, open new perspectives toward architecture and patterning of functional films and are extensively reviewed.
Electrochemical carbon dioxide (CO2) reduction is a promising strategy to synthesize valuable multi-carbon products (C2+) while sequestering CO2 and utilizing intermittent renewable electricity. For ...industrial deployment, CO2 electrolyzers must remain stable while selectively producing concentrated C2+ products at high rates with modest cell voltages. Here, we present a membrane electrode assembly (MEA) electrolyzer that converts CO2 to C2+ products. We perform side-by-side comparisons of state-of-the-art electrolyzer systems and find that the MEA provides the most stable cell voltage and product selectivity. We then demonstrate an approach to release concentrated gas and liquid products from the cathode outlet. This strategy achieves ∼50% and ∼80% Faradaic efficiency for ethylene and C2+ products, respectively, with cathode outlet concentrations of ∼30% ethylene and the direct production of ∼4 wt % ethanol. We characterize stability by operating continuously for 100 h, the longest stable ethylene production at current densities >100 mA cm−2 among reported CO2 electrolyzers.
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•Membrane electrode assembly design enables stable CO2 electroreduction•∼50% Faradaic efficiency for ethylene and ∼80% Faradaic efficiency for C2+ products•>30% gas outlet concentration of ethylene and direct production of ∼4 wt % ethanol•Continuous 100 h operation at >100 mA cm−2
The advent of low-cost renewable electricity and rising atmospheric CO2 has led to a focus on electrochemical CO2 reduction as a means toward low-carbon-intensity fuels and chemical feedstocks. The conversion of CO2 into C2+ hydrocarbons and oxygenates (i.e., products containing two or more carbon atoms) is attractive in light of large global market demand for these high-energy-density products. A limited number of prior studies have focused on performance in the reaction rate regime above 100 mA cm−2 generally viewed as necessary for industrial deployment. In these works, gas diffusion electrodes are used in liquid electrolyte electrochemical flow cells, which suffer in system stability and/or energy efficiency. We overcome this issue by developing a membrane electrode assembly-based electrolyzer. The combined catalyst and system strategy produces concentrated gas and liquid products and maintains performance during long-term (100 h) uninterrupted operation.
Electrochemical CO2 reduction is a promising strategy to synthesize valuable multi-carbon products (C2+) while sequestering CO2 and utilizing intermittent renewable electricity. Here, we present a stable membrane electrode assembly (MEA) electrolyzer that converts CO2 to C2+ products. This strategy achieves ∼50% and ∼80% selectivity for ethylene and C2+ products, respectively, with cathode outlet concentrations of ∼30% ethylene and the direct production of ∼4 wt % ethanol. We characterize stability by operating continuously for 100 h with steady ethylene production.
Deposition of Ni‐based cyanide bridged coordination polymer (NiCNNi) flakes onto the surfaces of graphene oxide (GO) sheets, which allows precise control of the resulting lamellar nanoarchitecture by ...in situ crystallization, is reported. GO sheets are utilized as nucleation sites that promote the optimized crystal growth of NiCNNi flakes. The NiCNNi‐coated GO sheets then self‐assemble and are stabilized as ordered lamellar nanomaterials. Regulated thermal treatment under nitrogen results in a Ni3C–GO composite with a similar morphology to the starting material, and the Ni3C–GO composite exhibits outstanding electrocatalytic activity and excellent durability for the oxygen reduction reaction.
Layer cake: Deposition of nickel‐based cyano‐bridged coordination polymer (NiCNNi) flakes on the surface of graphene oxide (GO) sheets allows the formation of lamellar nanoarchitectures. Regulated thermal treatment under nitrogen produces an Ni3C–GO composite with a similar morphology to the starting material. This approach may be applicable to other inorganic–organic hybrids for the formation of ordered layer‐by‐layer (LbL) architectures.
Di- and tripyrrin sensors D1-D4 exhibit CHEF-type fluorescence enhancement by factors up to 72 upon addition of 1 equiv. Zn(2+), with tunable emission colours between green (D1) and red (D4).
In nuclear pre-messenger RNA splicing, introns are excised by the spliceosome, a dynamic machine composed of both proteins and small nuclear RNAs (snRNAs). Over thirty years ago, after the discovery ...of self-splicing group II intron RNAs, the snRNAs were proposed to catalyse splicing. However, no definitive evidence for a role of either RNA or protein in catalysis by the spliceosome has been reported so far. By using metal rescue strategies in spliceosomes from budding yeast, here we show that the U6 snRNA catalyses both of the two splicing reactions by positioning divalent metals that stabilize the leaving groups during each reaction. Notably, all of the U6 catalytic metal ligands we identified correspond to the ligands observed to position catalytic, divalent metals in crystal structures of a group II intron RNA. These findings indicate that group II introns and the spliceosome share common catalytic mechanisms and probably common evolutionary origins. Our results demonstrate that RNA mediates catalysis within the spliceosome.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Alpha-fetoprotein (AFP) predicts hepatocellular carcinoma (HCC) recurrence after liver transplant (LT) but remains an imperfect biomarker. The role of DCP (des-gamma-carboxyprothrombin) and AFP-L3 ...(AFP bound to Lens culinaris agglutinin) in predicting HCC recurrence remains incompletely characterized. AFP-L3 and DCP could identify patients at high risk of post-transplant HCC recurrence and serve as liver transplant exclusion criteria to defer transplant until patients receive additional risk-reducing pre-transplant locoregional therapy.
This prospective cohort study included consecutive patients with HCC who underwent LT (within or down-staged to Milan criteria) between 2017 and 2022. Pre-transplant AFP, AFP-L3, and DCP measurements were obtained. The primary endpoint was the ability of biomarkers to predict HCC recurrence-free survival.
This cohort included 285 patients with a median age of 67 (IQR 63-71). At LT, median biomarker values were AFP 5.0 ng/ml (IQR 3.0-12.1), AFP-L3 6.7% (0.5-13.2), and DCP 1.0 ng/ml (0.3-2.8). Most (94.7%) patients received pre-LT locoregional therapy. After a median post-LT follow-up of 3.1 years, HCC recurrence was observed in 18 (6.3%) patients. AFP-L3 and DCP outperformed AFP with C-statistics of 0.81 and 0.86 respectively, compared with 0.74 for AFP. A dual-biomarker combination of AFP-L3 ≥15% and DCP ≥7.5 predicted 61.1% of HCC recurrences, whereas HCC only recurred in 7 of 265 (2.6%) patients not meeting this threshold. The Kaplan-Meier recurrence-free survival rate at 3 years post-LT was 43.7% for patients with dual-positive biomarkers compared to 97.0% for all others (p <0.001).
Dual-positivity for AFP-L3 ≥15% and DCP ≥7.5 strongly predicted post-LT HCC recurrence. This model could refine LT selection criteria and identify high-risk patients who require additional locoregional therapy prior to LT.
Alpha-fetoprotein (AFP) is used to predict hepatocellular carcinoma (HCC) recurrence after liver transplant, but it remains an imperfect biomarker. In this prospective study, the biomarkers DCP (des-gamma-carboxyprothrombin) and AFP-L3 (AFP bound to Lens culinaris agglutinin) strongly predicted early HCC recurrence and outperformed AFP. A dual-biomarker combination of AFP-L3 ≥15% and DCP ≥7.5 predicted the majority of recurrences and could be used to further refine liver transplant eligibility criteria.
•The distributions of a subbituminous coal fringes were quantified by HRTEM.•The evolution of size of the coal chars aromatic sheet were investigated.•Impact of temperature on gold-tube pyrolysis ...chars was evaluated.•Coal thermoplastic behavior was present between ∼450 and 500 °C by fringe lengths.•The pyrolysis could be divided into three stages by the fringe orientation.
Structural transformations accompanying coalification can be explored by gold-tube pyrolysis. There the pyrolysis products are retarded by the high gas pressure and the slow-heating with temperature soak can somewhat simulate in situ conditions in a laboratory setting. Coalification process under geological conditions can be explained. While there has been considerable research expenditure on bituminous and anthracite coals, the subbituminous coals have been less-well explored. Here, the structural transformations accompanying subbituminous coal during heating were followed using HRTEM image analysis. Specifically the distributions of fringe: length, orientation, stacking, and curvature were quantified. Pyrolysis was performed under N2 at a slow heating rate of 20 °C/h with a 50 MPa initial (cold) confining pressure. Temperatures between 325 and 590 °C were explored. Each sample was temperature soaked for 1 h and allowed to cool slowly to room temperature. The structural transformations accompanying pyrolysis could be divided into three stages by the fringe orientation within a 45° bin capturing any thermoplastic transformations. In stage one: 325∼432 °C there is some growth in the lattice fringe lengths and the distribution broadens. In stage two: 456∼504 °C there is an enhanced partial ordering (orientation and stacking) indicating some thermoplastic transformations occur for this subbituminous coal. In stage three: 524∼590 °C the partial ordering extent is reduced. Presumably at higher temperatures the appropriate balance between mass loss, tar viscosity, and other properties are not in balance for significantly improved thermoplastic behavior—although there is a recovery at highest temperatures explored here. These results can provide some structural transformations for a subbituminous coal and could influence the strategy for attempting to produce coke from subbituminous coal.
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