Why Do Sulfone-Based Electrolytes Show Stability at High Voltages? Insight from Density Functional Theory

Sulfone-based electrolytes have attracted a great attention due to their high oxidation stability comparing to conventional carbonates. However, the ab initio calculated oxidation potentials (<i>E</i>_ox) of isolated sulfones are lower than those for carbonates. To understand this contradiction, the oxidations of three carbonates and eleven sulfones in a presence of anions and other solvent molecules have been investigated by the density functional theory calculations with a polarized continuum model. Importantly, we found that the <i>E</i>_ox of some of the sulfones show surprisingly high stability toward the presence of anions and another solvent, which is the key factor of high oxidation stability of these electrolytes compared to carbonates. Finally, the way to design new high oxidation stability sulfones by modifying their functional groups is discussed

Mechanistic Insight into Decomposition of 2<i>H</i>‑Azirines: Electronic Structure Calculations and Dynamics Simulations

In the present work, the combined electronic structure calculations and dynamics simulations have been performed to explore the decomposition reactions of 2<i>H</i>-azirine, 2-phenyl-2<i>H</i>-azirine, and 3-phenyl-2<i>H</i>-azirine in gas phase. Thermal cleavage of the C–C single bond yields nitrile ylides as products with a high barrier (>50.0 kcal mol^–1). On the other hand, photochemical cleavage reactions starting from the ¹nπ* state of 2<i>H</i>-azirine and 3-phenyl-2<i>H</i>-azirine are ultrafast nonadiabatic processes (<100 fs), leading to nitrile ylides through the S₁/S₀ conical intersection. The fast formation of ylides in experiments was well reproduced by present dynamics simulations. For 3-phenyl-2<i>H</i>-azirine, population of the S₁(¹ππ*) state is another decay pathway for the S₂(¹nπ*) state. The C–N bond cleavage upon photoexcitation was usually considered to take place in T₁ state. However, our calculations reveal that photocleavage of the C–N single bond for 2-phenyl-2<i>H</i>-azirine is very likely to take place in S₁ state. The present work provides new insights into photocleavage mechanism of 2<i>H</i>-azirine and the related derivatives

Interactions of Lignin with Optical Brightening Agents and Their Effect on Paper Optical Properties

Optical brightening agents (OBAs) are widely used in the production of uncoated and coated paper grades to improve their optical properties. The presence of lignin in the pulp furnishes is well-known to have a significant effect on the OBA brightening efficiency, but how OBA interacts with lignin is still not well understood. In this study we used wood lignin to investigate the lignin/OBA interactions and its effect on OBA brightening. Three lignin samples isolated from spruce, pine, and aspen were used. Both di- and tetra-sulfonated OBAs were studied. It was found that the OBA addition can effectively improve the optical properties of paper, such as ISO brightness, CIE whiteness, and <i>b</i>*, but disulfonated OBA was found to be more effective at a lower dosage (less than 0.6%) than the tetra-sulfonated OBA. The addition of a small amount of lignin (0.4%) onto filter paper had negative effects on the optical properties, but the impact depends strongly on lignin structures (lignin samples from spruce, pine, and aspen), which explain the early results that mechanical pulps from different wood species respond very differently to OBA brightening. A modified Kubelka–Munk equation was used to predict and model the brightness and whiteness response of different lignin types and OBA, which can be used to provide guidance in determining the amount of OBA needed to reach specified optical property target

FeNC catalysts decorated with NiFe₂O₄ to enhance bifunctional activity for Zn–Air batteries

Rechargeable Zn–air battery is a promising next-generation energy storage device attributed to its high energy density, excellent safety, and low cost. However, its commercialization is hampered by sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at air electrodes. Herein, we have designed, fabricated, and demonstrated a highly efficient ORR/OER electrocatalyst, NiFe2O4/FeNC, using low-cost materials via a facile synthesis route. NiFe2O4 is successfully loaded on Fe/N-doped carbon (FeNC) through bonding to Fe3C in FeNC. Due to the existence of high ORR active sites such as FeN4 and Fe and N-doped carbon moieties, the half-wave potential of the ORR reaches a high value of 0.83 V. While benefited from NiFe2O4 with high OER activity and the synergistic effect between NiFe2O4 and FeNC, the overpotential is 310 mV at 10 mA cm–2 in the OER. The voltage difference between charging–discharging operations in the Zn–air battery employing the NiFe2O4/FeNC electrocatalyst only increases by 0.16 V after cycling for 100 h (600 cycles) at 10 mA cm–2, which is much lower than 1.28 V using the best commercial Pt/C and RuO2 catalysts. </p

Thermally Activated Delayed Fluorescent Emitters Based on Cyanobenzene Exhibiting Fast Reverse Intersystem Crossing to Suppress the Efficiency Roll-Off

Thermally activated delayed fluorescent (TADF) materials exhibiting the fast reverse intersystem crossing (RISC) process are essential for improving the stability of organic light-emitting diodes (OLEDs). However, for most TADF emitters, the upconversion processes from the lowest triplet state (T1) to the lowest singlet state (S1) are still inefficient due to the low RISC (kRISC) rate below 105 s–1. Herein, we report two TADF molecules, 2DACz-mCN and 2DACz-oCN, that possess multiple donor units to minimize singlet–triplet energy splitting (ΔEST) and enhance the spin–orbit coupling matrix elements. Our work shows that the rate constants of RISC of 2DACz-mCN and 2DACz-oCN are as fast as ∼2.7 × 106 and ∼8.6 × 106 s–1, which are 1 order of magnitude higher than the other benzonitrile-based TADF molecules. The short delayed fluorescent lifetimes of ∼1.58 and ∼1.16 μs in doped films are achieved. The OLEDs by utilizing 2DACz-oCN as emitter exhibit green electroluminescence (EL) with CIE chromaticity coordinates of (0.28, 0.49) and high maximum quantum efficiency of ∼25.1% with the suppressed efficiency roll-off, which still remains ∼21% at the luminance of 1000 cd/m2

Supplementary information files for FeNC catalysts decorated with NiFe2O4 to enhance bifunctional activity for Zn–Air batteries

Supplementary files for article FeNC catalysts decorated with NiFe2O4 to enhance bifunctional activity for Zn–Air batteries  Rechargeable Zn–air battery is a promising next-generation energy storage device attributed to its high energy density, excellent safety, and low cost. However, its commercialization is hampered by sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at air electrodes. Herein, we have designed, fabricated, and demonstrated a highly efficient ORR/OER electrocatalyst, NiFe2O4/FeNC, using low-cost materials via a facile synthesis route. NiFe2O4 is successfully loaded on Fe/N-doped carbon (FeNC) through bonding to Fe3C in FeNC. Due to the existence of high ORR active sites such as FeN4 and Fe and N-doped carbon moieties, the half-wave potential of the ORR reaches a high value of 0.83 V. While benefited from NiFe2O4 with high OER activity and the synergistic effect between NiFe2O4 and FeNC, the overpotential is 310 mV at 10 mA cm–2 in the OER. The voltage difference between charging–discharging operations in the Zn–air battery employing the NiFe2O4/FeNC electrocatalyst only increases by 0.16 V after cycling for 100 h (600 cycles) at 10 mA cm–2, which is much lower than 1.28 V using the best commercial Pt/C and RuO2 catalysts.  </p

Fragmentation of Peptide Radical Cations Containing a Tyrosine or Tryptophan Residue: Structural Features That Favor Formation of [<i>x</i>_{(<i>n</i>–1)} + H]^•+ and [<i>z</i>_{(<i>n</i>–1)} + H]^•+ Ions

Peptide radical cations A_<i>n</i>Y^•+ (where <i>n</i> = 3, 4, or 5) and A₅W^•+ have been generated by collision-induced dissociation (CID) of [Cu^II(tpy)­(peptide)]^•2+ complexes. Apart from the charge-driven fragmentation at the N–C_α bond of the hetero residue producing either [<i>c</i> + 2H]⁺ or [<i>z</i> – H]^•+ ions and radical-driven fragmentation at the C_α–C bond to give <i>a</i>⁺ ions, unusual product ions [<i>x</i> + H]^•+ and [<i>z</i> + H]^•+ are abundant in the CID spectra of the peptides with the hetero residue in the second or third position of the chain. The formation of these ions requires that <i>both</i> the charge and radical be located on the peptide backbone. Energy-resolved spectra established that the [<i>z</i> + H]^•+ ion can be produced either directly from the peptide radical cation or via the fragment ion [<i>x</i> + H]^•+. Additionally, backbone dissociation by loss of the C-terminal amino acid giving [<i>b</i>_{(<i>n</i>–1)} – H]^•+ increases in abundance with the length of the peptides. Mechanisms by which peptide radical cations dissociate have been modeled using density functional theory (B3LYP/6-31++G** level) on tetrapeptides AYAG^•+, AAYG^•+, and AWAG^•+

Data_Sheet_2_Identification of key gene networks controlling polysaccharide accumulation in different tissues of Polygonatum cyrtonema Hua by integrating metabolic phenotypes and gene expression profiles.xlsx

Plant polysaccharides, a type of important bioactive compound, are involved in multiple plant defense mechanisms, and in particular polysaccharide-alleviated abiotic stress has been well studied. Polygonatum cyrtonema Hua (P. cyrtonema Hua) is a medicinal and edible perennial plant that is used in traditional Chinese medicine and is rich in polysaccharides. Previous studies suggested that sucrose might act as a precursor for polysaccharide biosynthesis. However, the role of sucrose metabolism and transport in mediating polysaccharide biosynthesis remains largely unknown in P. cyrtonema Hua. In this study, we investigated the contents of polysaccharides, sucrose, glucose, and fructose in the rhizome, stem, leaf, and flower tissues of P. cyrtonema Hua, and systemically identified the genes associated with the sucrose metabolism and transport and polysaccharide biosynthesis pathways. Our results showed that polysaccharides were mainly accumulated in rhizomes, leaves, and flowers. Besides, there was a positive correlation between sucrose and polysaccharide content, and a negative correlation between glucose and polysaccharide content in rhizome, stem, leaf, and flower tissues. Then, the transcriptomic analyses of different tissues were performed, and differentially expressed genes related to sucrose metabolism and transport, polysaccharide biosynthesis, and transcription factors were identified. The analyses of the gene expression patterns provided novel regulatory networks for the molecular basis of high accumulation of polysaccharides, especially in the rhizome tissue. Furthermore, our findings explored that polysaccharide accumulation was highly correlated with the expression levels of SUS, INV, SWEET, and PLST, which are mediated by bHLH, bZIP, ERF, ARF, C2H2, and other genes in different tissues of P. cyrtonema Hua. Herein, this study contributes to a comprehensive understanding of the transcriptional regulation of polysaccharide accumulation and provides information regarding valuable genes involved in the tolerance to abiotic stresses in P. cyrtonema Hua.</p

Data_Sheet_1_Identification of key gene networks controlling polysaccharide accumulation in different tissues of Polygonatum cyrtonema Hua by integrating metabolic phenotypes and gene expression profiles.docx

Plant polysaccharides, a type of important bioactive compound, are involved in multiple plant defense mechanisms, and in particular polysaccharide-alleviated abiotic stress has been well studied. Polygonatum cyrtonema Hua (P. cyrtonema Hua) is a medicinal and edible perennial plant that is used in traditional Chinese medicine and is rich in polysaccharides. Previous studies suggested that sucrose might act as a precursor for polysaccharide biosynthesis. However, the role of sucrose metabolism and transport in mediating polysaccharide biosynthesis remains largely unknown in P. cyrtonema Hua. In this study, we investigated the contents of polysaccharides, sucrose, glucose, and fructose in the rhizome, stem, leaf, and flower tissues of P. cyrtonema Hua, and systemically identified the genes associated with the sucrose metabolism and transport and polysaccharide biosynthesis pathways. Our results showed that polysaccharides were mainly accumulated in rhizomes, leaves, and flowers. Besides, there was a positive correlation between sucrose and polysaccharide content, and a negative correlation between glucose and polysaccharide content in rhizome, stem, leaf, and flower tissues. Then, the transcriptomic analyses of different tissues were performed, and differentially expressed genes related to sucrose metabolism and transport, polysaccharide biosynthesis, and transcription factors were identified. The analyses of the gene expression patterns provided novel regulatory networks for the molecular basis of high accumulation of polysaccharides, especially in the rhizome tissue. Furthermore, our findings explored that polysaccharide accumulation was highly correlated with the expression levels of SUS, INV, SWEET, and PLST, which are mediated by bHLH, bZIP, ERF, ARF, C2H2, and other genes in different tissues of P. cyrtonema Hua. Herein, this study contributes to a comprehensive understanding of the transcriptional regulation of polysaccharide accumulation and provides information regarding valuable genes involved in the tolerance to abiotic stresses in P. cyrtonema Hua.</p

Additional file 1: of Soluble epoxide hydrolase inhibitors, t-AUCB, downregulated miR-133 in a mouse model of myocardial infarction

Figure S1. Effects of different doses of agomir-133 (15, 25, 40 nM) on expression of miR-133 in ischemic myocardium. Figure S2. MicroRNA profile changes between sham and MI mice treated with or without t-AUCB. Figure S3. Effect of t-AUCB on primary neonatal mouse ventricular myocytes viability. Table S1. Significantly up-regulated miRNAs in ischemic myocardium between sham-operated animals with MI mice treated with or without t-AUCB. Table S2. Significantly down-regulated miRNAs in ischemic myocardium between sham-operated animals with MI mice treated with or without t-AUCB. (DOCX 1178 kb