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N6-methyladenosine (m6A) modification and m6A-modified Long non-coding RNAs (LncRNAs) play crucial roles in various pathological processes, yet their changes and relationship in cadmium-induced oxidative damage are largely unknown. Here, five m6A-modified LncRNAs (LncRNA-TUG1, LncRNA-PVT1, LncRNA-MALAT1, LncRNA-XIST, LncRNA-NEAT1), which have been evidenced to involve in oxidative damage, were selected and their binding proteins were submitted to bioinformatics analysis. Our analysis results showed that these five m6A-modified LncRNAs bound to different regulatory proteins of m6A modification, implicating that m6A modification on LncRNAs may synergistically control by multiple regulatory proteins. Furthermore, the detection data revealed that levels of m6A modification, methyltransferase-like 3 (METTL3) and fat mass and obesity-associated protein (FTO) were all significantly decreased in CdSO4-induced oxidative damage, which was demonstrated by increasing ROS accumulation and MDA contents as well as decreasing SOD activities. More importantly, LncRNA-MALAT1 and LncRNA-PVT1 indicated downward trend and showed positive relationship with m6A modification. Collectively, our results showed that m6A modification and m6A-modified LncRNAs may involve in oxidative damage induced by cadmium.

Imbalance of macrophage polarization plays an indispensable role in acute lung injury (ALI), which is considered as a promising target. Matrix metalloproteinase-9 (MMP-9) is expressed in the macrophage, and has a pivotal role in secreting inflammatory cytokines. We reported that saquinavir (SQV), a first-generation human immunodeficiency virus-protease inhibitor, restricted exaggerated inflammatory response. However, whether MMP-9 could regulate macrophage polarization and inhibit by SQV is still unknown. We focused on the important role of macrophage polarization in CLP (cecal ligation puncture)-mediated ALI and determined the ability of SQV to maintain M2 over M1 phenotype partially through the inhibition of MMP-9. We also performed a limited clinical study to determine if MMP-9 is a biomarker of sepsis. Lipopolysaccharide (LPS) increased MMP-9 expression and recombinant MMP-9 (rMMP-9) exacerbated LPS-mediated M1 switching. Small interfering RNA to MMP-9 inhibited LPS-mediated M1 phenotype and SQV inhibition of this switching was reversed with rMMP-9, suggesting an important role for MMP-9 in mediating LPS-induced M1 phenotype. MMP-9 messenger RNA levels in peripheral blood mononuclear cells of these 14 patients correlated with their clinical assessment. There was a significant dose-dependent decrease in mortality and ALI after CLP with SQV. SQV significantly inhibited LPS-mediated M1 phenotype and increased M2 phenotype in cultured RAW 264.7 and primary murine bone marrow-derived macrophages as well as lung macrophages from CLP-treated mice. This study supports an important role for MMP-9 in macrophage phenotypic switching and suggests that SQV-mediated inhibition of MMP-9 may be involved in suppressing ALI during systemic sepsis.

Background Oxidative stress plays an important role in initiating the destruction of melanocytes, which could be one possible mechanism of vitiligo. PINK1 is an outer membrane protein of mitochondria, which protects many cells from oxidative stress through regulating mitochondrial function. However, the role of PINK1 and its effects on oxidative damage in melanocytes have not been elucidated. Aim To investigate the expression and effects of PINK1 on oxidative stress in human melanocytes. Methods RT-qPCR and Western blot analysis were used to analyze the expression of PINK1 in PIG1 melanocyte and gene downregulation models. Levels of cell viability, cell apoptosis, intracellular ROS, morphology of mitochondria, mitochondrial membrane potential and transition pore opening were measured in PIG1 transfected with PINK1 siRNA with or without H2 O2 . Results We first observed the expression of PINK1 in human PIG1 melanocytes and found that downregulation of PINK1 made melanocytes more sensitive to oxidative stress induced by H2 O2 with more cell apoptosis and increased intracellular ROS. Meanwhile, downregulation of PINK1 caused morphological changes of mitochondria, decreased mitochondrial membrane potential and increased MPTP opening. Conclusions Our study found PINK1 plays an essential role in protecting human melanocytes from oxidative stress.

Betulinic acid (BA) is a natural antitumor agent and has biological activity against multiple human tumor cell lines with low cytotoxicity to normal cells, while the high hydrophobicity and the short half-life of this compound limit its clinical application. Here, gelatin-based dual-targeted nanoparticles of BA are promising to solve this problem. Hydrophobic BA is loaded in cyclodextrin to increase its solubility and prolong the circulation time in vivo. The nanoscale drug delivery systems can further enhance the bioavailability and the antitumor effect of BA and are passively targeted to the tumor tissue sites by enhanced permeability and retention effect. The RGD sequence of gelatin specifically recognizes tumor cells and brings agents into tumor cells. The nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared, nuclear magnetic resonance, etc. In addition, we observed antitumor activity of the nanoparticles using both cell-based assays and mouse xenograft tumors, which proved that betulinic acid/gelatin-γ-cyclodextrin nanoparticles had a better tumor inhibition effect than betulinic acid/γ-cyclodextrin inclusion compound.

Biomass-derived ethyl levulinate (EL) is currently deemed as a promising fuel bioadditive to improve (bio)diesel combustion performance without the sacrifice of its octane number. In this contribution, a range of Zr–Al bimetallic catalysts were prepared for the cascade conversion of furfural to EL by the integration of transfer hydrogenation and ethanolysis in ethanol. The ratio of Lewis to Bronsted acid sites (L/B) could be tuned by the ratio of Al2O3 to ZrO2 over SBA-15 support. Among these catalysts, Zr–Al/SBA-15(30:10) with appropriate L/B ratio of 2.25 exhibited an outstanding catalytic performance to give a furfural (FF) conversion up to 92.8% with a EL selectivity as high as 71.4% at 453 K in 3 h.

Trichoderma reesei is the major filamentous fungus used to produce cellulase and there is huge interest in promoting its ability to produce higher titers of cellulase. Among the many factors affecting cellulase production in T. reesei, the mycelial phenotype is important but seldom studied. Herein, a close homolog of the Neurospora crassa COT1 kinase was discovered in T. reesei and designated TrCOT1, which is of 83.3% amino acid sequence identity. Functional disruption of Trcot1 in T. reesei by RNAi-mediated gene silencing resulted in retarded sporulation on potato dextrose agar and dwarfed colonies on minimal medium agar plates containing glucose, xylan, lactose, xylose, or glycerol as the sole carbon source. The representative mutant strain, SUS2/Trcot1i, also displayed reduced mycelia accumulation but hyperbranching in the MM glucose liquid medium, with hyphal growth unit length values decreased to 73.0 µm/tip compared to 239.8 µm/tip for the parent strain SUS2. The hyperbranching phenotype led to slightly but significantly increased cellulase secretion from 24 to 72 h in a batch culture. However, the cellulase production per unit of mycelial biomass was much more profoundly improved from 24 to 96 h.

Fe-based catalysts have been discovered as the best elementary metal-based heterogeneous catalysts for the ammonia synthesis in industrial application during the last century. Herein, a novel and scalable strategy is developed to prepare the K-promoted Fe/C catalyst with extremely high Fe loading (> 50 wt.%) through pyrolysis of the Fe-based metal-organic framework (MOF) xerogel. The obtained K-Fe/C catalysts exhibited superior activity and stability towards ammonia synthesis. The weight-specific reaction rate of Fe/C with K2O as promoter can achieve 12.4 mmol·g−1·h−1 at 350 °C and 30.4 mmol·g−1·h−1 at 400 °C, approximately four and two times higher than that of the commercial fused-iron catalyst (3.4 mmol·g−1·h−1 at 350 °C and 16.7 mmol·g−1·h−1 at 400 °C) under the same condition, respectively. The excellent performance of K-Fe/C can be ascribed to the inherited structure derived from the metal-organic frame precursors and the promotion of potassium, which can modify the binding energy of reactant molecules on the Fe surface, transfer electrons to iron for effective activation of nitrogen, prevent agglomeration of Fe nanoparticle (NPs) and restrain side reaction of carbon matrix to methane.

It is challenging to effectively convert 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), a flexible biobased building-block, over non-noble metal catalysts. In this contribution, Mn–Fe oxides were prepared and served as highly active catalysts for the selective oxidation of HMF to DFF. Among Mn–Fe oxides with varied Mn–Fe molar ratios, Mn6Fe1Ox showed the best catalytic activity and offered HMF conversion up to 97% with a DFF selectivity of 98% (110 °C, 5 h, and 1.5 MPa O2). It is revealed that the introduction of α-Fe2O3 resulted in significant enhancement in the amount of catalytic active sites (Mn4+–O2– pairs) and their activity in Mn6Fe1Ox for the dehydrogenation of HMF to DFF. Mn6Fe1Ox also was a robust catalyst that could be successively used at least six times without substantial loss in its catalytic activity. Furthermore, a facile two-step process for the conversion of fructose to DFF with a yield up to 80% was developed by the integration of dehydration and oxidation over Amberlyst-15 ...

Recent studies revealed the emerging role of excess uptake of lipids in the development of hypothyroidism. However, the underlying mechanism is largely unknown. We investigated the effect of high-fat diet (HFD) on thyroid function and the role of endoplasmic reticulum (ER) in HFD-induced hypothyroidism. Male Sprague-Dawley rats were fed with HFD or control diet for 18 wk. HFD rats showed an impaired thyroid function, with decreased thyroglobulin (Tg) level. We found the ER stress was triggered in HFD rat thyroid glands and palmitate-treated thyrocytes. Luminal swelling of ER in thyroid epithelial cells of HFD rats was also observed. The rate of Tg degradation increased in palmitate-treated thyrocytes. In addition, applying 4-phenyl butyric acid to alleviate ER stress in HFD rats improved the decrease of Tg and thyroid function. Withdrawal of the HFD improved thyroid function . In conclusion, we demonstrate that ER stress mediates the HFD-induced hypothyroidism, probably by impairing the production of Tg, and attenuation of ER stress improves thyroid function. Our study provides the understanding of how HFD induces hypothyroidism.

Fingerprints of 20 batches of Malus micromalus Makino fruit were established by HPLC coupled with hierarchical cluster analysis (HCA) and principal component analysis (PCA) to estimate the common peaks on the basis of traditional similarity evaluation methods. Chromatographic peaks were identified as p-coumaric acid (P2), ferulic acid glycoside (P6), 4-O-β-Glucopyranosyl-cis-coumaric acid (P8), phloretin-2′-xyloglucoside (P10), phloridzin (P11) and quercetin-3-O-α-rhamnoside (P12) by UPLC-MS/MS method. The results of tyrosinase kinetics experiments showed that: P2 and the concentration of P11 was greater than 0.50 mmol/L mainly had a competitive inhibitory effect on tyrosinase, and the concentration of phlorizin was less than at 0.25 mmol/L, it has a mixed inhibitory effect. P8 was mainly a non-competitive activation type in the concentration range, while P12 was a mixed activation type. The results of tyrosinase molecular docking showed that: P2, P8, P11, P12 was located in the active center of the hydrophobic pocket of the enzyme. They bound to tyrosinase residues by hydrogen bonds and interacted with many hydrophobic residues around them to maintain the structure of the complex. This research provides a rapid method to determine the active compounds in edible plants with the technology of spectrum-effect relationship, component knock-out and molecular docking.

Phloem loading is the first step in sucrose transport from source leaves to sink organs. The phloem loading strategy in rice remains unclear. To determine the potential phloem loading mechanism in rice, yeast invertase (INV) was overexpressed by a 35S promoter specifically in the cell wall to block sugar transmembrane loading in rice. The transgenic lines exhibited obvious phloem loading suppression characteristics accompanied by the accumulation of sucrose and starch, restricted vegetative growth and decreased grain yields. The decreased sucrose exudation rate with p-chloromercuribenzenesulfonic acid (PCMBS) treatment also indicated that rice actively transported sucrose into the phloem. OsSUT1 (SUCROSE TRANSPORTER 1) showed the highest mRNA levels of the plasma membrane-localized OsSUTs in source leaves. Cross sections of the OsSUT::GUS transgenic plants showed that the expression of OsSUT1 and OsSUT5 occurred in the phloem companion cells. Rice ossut1 mutants showed reduced growth and grain yield, supporting the hypothesis of OsSUT1 acting in phloem loading. Based on these results, we conclude that apoplastic phloem loading plays a major role in the export of sugar from rice leaves.

In this study, dissociative one-electron transfer dissociation of [CuII (dien)Y(G/A)W]•2+ [dien = diethylenetriamine; Y(G/A)W = tyrosyl (glycyl/alanyl)tryptophan] was used to generate the tripeptide radical cations [Y(G/A)W]•+ ; subsequent loss of the Tyr side chain formed [Gα• (G/A)W]+ . The π-centered species [YGWπ• ]+ generated the α-centered species [Gα• GW]+ through Cα -Cβ bond cleavage, as revealed using infrared multiple photon dissociation (IRMPD) measurements and density functional theory (DFT) calculations. Comparisons of experimental and theoretical IR spectra confirmed that both the charge and spin densities of [Y(G/A)Wπ• ]+ were delocalized initially at the tryptophan indolyl ring; subsequent formation of the final [Gα• (G/A)W]+ structure gave the highest spin density at the α-carbon atom of the N-terminal glycine residue, with a proton solvated by the first amide oxygen atom. The IRMPD mass spectra and action spectra of the [Gα• (G/A)W]+ species were all distinctly different from those of their isomeric [G(G/A)Wπ• ]+ species. The mechanism of formation of the captodative [Gα• (G/A)W]+ species-with the charge site separated from the radical site-from [Y(G/A)Wπ• ]+ has been elucidated. DFT calculations suggested that the Cα -Cβ bond cleavage of the tyrosine residue in the radical cationic [Y(G/A)Wπ• ]+ precursor involves (a) through-space electron transfer between the indolyl and phenolic groups; (b) formation of proton-bound dimers through Cα -Cβ cleavage of the tyrosine residue; and (c) a concerted proton rearrangement from the phenolic OH group to the carboxyl group and formation of the α-carbon-centered product [Gα• (G/A)W]+ through hydrogen bond cleavage. The barriers for the electron transfer (a), the Cα -Cβ cleavage (b), and the protonation rearrangement (c) were 12.8, 26.5, and 10.3 kcal mol-1 , respectively.

Multidimensional liquid chromatography is the mainstay separation technique used for shotgun proteomic analyses. The application of a multiple-fraction concatenation (MFC) strategy can result in a more disperse and consistent peptide elution profile across different fractions, when compared with a conventional strategy. Herein, we present the first automated online RP-RP platform implementing an MFC strategy to facilitate robust, unattended, routine proteomic analyses. The improved duty cycle utilization of the MFC strategy led to an increase of 9% in the separation space occupancy and increases of approximately 10% in the identification of both proteins and peptides. The peptides uniquely identified by the MFC strategy were significantly biased toward those of acidic nature, with increased precursor signals leading to improved MS/MS spectral quality and enhanced acidic peptide identification. These improvements in qualitative analysis using the MFC strategy were also extended to quantitative analysis. When the acquired proteome was quantified with a normalized spectral abundance factor, the additionally acquired acidic peptides were a critical factor leading to enhanced reproducibility of quantitation using the MFC strategy. With merits of superior qualitative and quantitative characteristics over the conventional strategy, the MFC strategy appears to be a highly amenable technique for enhancing the separation capacity for routine proteomic analyses.

We present herein rPTMDetermine, an adaptive and fully automated methodology for validation of the identification of rarely occurring post-translational modifications (PTMs), using a semisupervised approach with a linear discriminant analysis (LDA) algorithm. With this strategy, verification is enhanced through similarity scoring of tandem mass spectrometry (MS/MS) comparisons between modified peptides and their unmodified analogues. We applied rPTMDetermine to (1) perform fully automated validation steps for modified peptides identified from an in silico database and (2) retrieve potential yet-to-be-identified modified peptides from raw data (that had been missed through conventional database searches). In part (1), 99 of 125 3-nitrotyrosyl-containing (nitrated) peptides obtained from a ProteinPilot search were validated and localized. Twenty nitrated peptides were falsely assigned because of incorrect monoisotopic peak assignments, leading to erroneous identification of deamidation and nitration. Five additional nitrated peptides were, however, validated after performing nonmonoisotopic peak correction. In part (2), an additional 236 unique nitrated peptides were retrieved and localized, containing 113 previously unreported nitration sites; 25 endogenous nitrated peptides with novel sites were selected and verified by comparison with synthetic analogues. In summary, we identified and confidently validated 296 unique nitrated peptides-collectively representing the largest number of endogenously identified 3-nitrotyrosyl-containing peptides from the cerebral cortex proteome of a Macaca fascicularis model of stroke. Furthermore, we harnessed the rPTMDetermine strategy to complement conventional database searching and enhance the confidence of assigning rarely occurring PTMs, while recovering many missed peptides. In a final demonstration, we successfully extended the application of rPTMDetermine to peptides featuring tryptophan oxidation.

We report herein the first detailed study of the mechanism of redox reactions occurring during the gas-phase dissociative electron transfer of prototypical ternary [CuII(dien)M]˙2+ complexes (M, peptide). The two final products are (i) the oxidized non-zwitterionic π-centered [M]˙+ species with both the charge and spin densities delocalized over the indole ring of the tryptophan residue and with a C-terminal COOH group intact, and (ii) the complementary ion [CuI(dien)]+. Infrared multiple photon dissociation (IRMPD) action spectroscopy and low-energy collision-induced dissociation (CID) experiments, in conjunction with density functional theory (DFT) calculations, revealed the structural details of the mass-isolated precursor and product cations. Our experimental and theoretical results indicate that the doubly positively charged precursor [CuII(dien)M]˙2+ features electrostatic coordination through the anionic carboxylate end of the zwitterionic M moiety. An additional interaction exists between the indole ring of the tryptophan residue and one of the primary amino groups of the dien ligand; the DFT calculations provided the structures of the precursor ion, intermediates, and products, and enabled us to keep track of the locations of the charge and unpaired electron. The dissociative one-electron transfer reaction is initiated by a gradual transition of the M tripeptide from the zwitterionic form in [CuII(dien)M]˙2+ to the non-zwitterionic M intermediate, through a cascade of conformational changes and proton transfers. In the next step, the highest energy intermediate is formed; here, the copper center is 5-coordinate with coordination from both the carboxylic acid group and the indole ring. A subsequent switch back to 4-coordination to an intermediate IM1, where attachment to GGW occurs through the indole ring only, creates the structure that ultimately undergoes dissociation.

Renewable and sustainable betaine-based catalysts (BX) derived from the betaine sugar industry or ChCl were developed for the production of 5-hydroxymethylfurfural (HMF) from various carbohydrates. The HMF yields in the BX-based media reached up to 88 %, 66 %, 37 % and 53 %, for the conversion of fructose, glucose, cellulose, and lignocellulosic biomass, respectively. In addition, choline-O-sulfate was synthesized and demonstrated to be an efficient catalyst for the conversion of fructose to HMF. From the perspective of green and sustainable chemistry, this work demonstrates benefits not only in the preparation of sustainable catalysts but also the green production of HMF from biomass.

Molecular radical cationic peptides (M +) display rich and diverse gas-phase ion chemistry that can differ substantially from that of their protonated counterparts. Dissociation of M + radical cations can provide relevant structural information for protein sequencing, often complementary to that obtained using traditional approaches. In this study, low-energy collision-induced dissociation (CID) of a series of tyrosine-containing peptide molecular radical cations having an N-terminal phenylalanine residue led to new products resulting from radical-mediated Cα–Cβ bond cleavage at the side chain of the phenylalanine residue. The chemical identity of the species formed through side chain loss (91 Da) occurring via N-terminal Cα–Cβ bond cleavage was examined using a combination of low-energy CID experiments, isotopic labeling mass spectrometric experiments, and density functional theory calculations. This unusual dissociation process occurs with fascinating unimolecular gas phase ion chemistry and requires a π-radical cationic tyrosine residue with significant spin density delocalized into the N-terminal amino group. The radical character at the resulting –NH2 + moiety then induces β-scission at the side chain Cα–Cβ bond of the phenylalanine residue. This discovery also demonstrates the role of the NH2 group in facilitating Cα–Cβ bond cleavage of the phenylalanine residue by the proximal tyrosine π-radical cation, probably involving a through-space electron transfer process.

Up-conversion (UC) oxides comprise a huge family of materials with abundant optical functionalities and they merit extensive research. Some members of this family have been modified with proper rare earth (RE3+) ions and their importance has recently been established in non-contact temperature sensors, although the thermal sensitivity (S) value was still low. In this study, we investigated Nd3+ and Yb3+ sensitized Ba4La2Ti4Nb6O30 (BLTN:xNd3+/Yb3+) with a tungsten bronze structure for use as optical thermometers for the first time. Under excitation at 980 nm, obvious near-infrared emissions corresponding to 4F7/2/4S3/2 → 4I9/2, 4F5/2/2H9/2 → 4I9/2, and 4F3/2 → 4I9/2 transitions were observed, and the UC mechanism involved was elaborated. Furthermore, the UC thermometric properties were investigated according to the fluorescence intensity ratio technique and the maximum S values determined for BLTN:xNd3+/Yb3+ (x = 0.12 and 0.16) samples were both higher than 0.03 K–1. The potential of BLTN:xNd3+/Yb3+ for use in optical thermometers was estimated based on comparisons with other active materials.

The poor solubility of raw cellulose greatly limits its applications. Herein, the periodate oxidation of cellulose was conducted to obtain dialdehyde cellulose (DAC), which is a kind of soluble and...

Summary With the depletion of crude oil and especially the growing demand for lower olefins, the direct conversion of syngas into lower olefins via the Fischer-Tropsch to olefins (FTO) process is a promising alternative for the petroleum route. A photo-driven FTO process can dramatically change the product selectivity over Fe5C2 catalyst, leading to an olefin/paraffin ratio of 10.9 with CO conversion >49%. The selectivity toward CO2 was as low as 18.9%, ensuring a high carbon resource utilization efficiency, and the catalyst showed good stability. Under the photo-irradiation condition, the surface of the Fe5C2 catalyst was spontaneously decorated by O atoms formed in situ, resulting in a high selectivity to olefins, which makes it an excellent catalyst for photo-driven FTO reaction.

Pyranose oxidase (POx) is a homotetrameric flavoprotein that catalyzes the oxidation of pyranose-configured sugars at position C-2 to corresponding 2-ketoaldoses. The wide substrate specificity makes POx potential for application in various biotechnological industries. In the present study we reported the gene cloning and heterologous expression of a POx from the basidiomycete Trametes sp. and functionally expressed the gene in Escherichia coli BL21(DE3). Based on sequence alignment, three residues were chosen for site-directed mutagenesis to obtain two single mutants (K312E and E539K) and two double mutants (T166A/E539K and K312E/E539K). In comparison to the wild-type, K312E shifted its optimal pH to 5.5 while the optimal temperature of E539K and K312E/E539K increased by 10 °C. The mutants retained more activities over broader pH ranges and higher temperatures and catalyzed d-glucose at higher efficiency (5800‒12,667 M−1 s−1 for the mutants versus 5083 M−1 s−1 for the wild-type). The recombinant POx and its mutants were all useful in gluten agglomeration and enlarging the loaf volume, which depends on the amounts of enzymes added. Interestingly, adding the same amount (0.5 nkat/g of flour) of wild-type and mutant enzymes differed in the change of loaf volumes, pinpointing that the catalytic activity is not the sole determinant in applying POx in breadmaking. Electronic supplementary material The online version of this article (10.1186/s13568-018-0570-y) contains supplementary material, which is available to authorized users.

Herein, we report the successful application of hybrid Au-Ag nanoparticles (NPs) and nanochains (NCs) in the harvesting of visible light energy for selective hydrogenation reactions. For individual Au@Ag NPs with Au25 cores, the conversion and turnover frequency (TOF) are approximately 8 and 10 times higher than those of Au25 NPs, respectively. Notably, after the self-assembly of the Au@Ag NPs, the conversion and TOF of 1D NCs were approximately 2.5 and 2 times higher than those of isolated Au@Ag NPs, respectively, owing to the coupling of surface plasmon and the increase in the rate at which hot (energetic) electrons are generated with the formation of plasmonic hot spots between NPs. Furthermore, the surface-enhanced Raman scattering (SERS) activity of 1D Au@Ag NCs was strengthened by nearly 2 orders of magnitude.

A series of Er3+- and Yb3+-doped K2LaNb5O15 (KLN:xEr3+/Yb3+) up-conversion (UC) submicro-particles have been synthesized for the first time by a simple and low-cost molten salt (MS) approach. X-ray diffraction (XRD) was performed to analyze the phase and structure, and the prepared KLN:xEr3+/Yb3+ samples exhibited a single phase tetragonal tungsten bronze (TTB) structure. The morphologies were characterized by scanning electron microscopy (SEM), and submicro-rod-like particles were obtained for all samples. Under 980 nm excitation, KLN:xEr3+/Yb3+ emitted bright green and weak red emissions which arose from the intra-4f transitions of Er3+ ions. The UC emission intensities and RR/G (the intensity ratio between red and green emissions) were disclosed to be tightly dependent on the Yb3+ ion concentration, and the involved UC luminescence mechanism was studied. Meanwhile, the slope of log I–log P plots displayed an evident reduction with a Ts (sintering temperature) increase, which was ascribed to the saturation effect coming from the competition between UC processes and linear decay. Furthermore, temperature-dependent UC behavior and temperature sensing properties of KLN:xEr3+/Yb3+ were probed based on the fluorescence intensity ratio (FIR) technique of UC green emission. The maximum sensor sensitivity (S) of KLN:0.04Er3+/Yb3+ (Ts = 900 °C) and KLN:0.16Er3+/Yb3+ (Ts = 900 °C) was determined to be as high as 10.90 × 10−3 and 12.27 × 10−3 K−1, respectively. We also showed that the particle size has an evident influence on S, which can be qualitatively interpreted by J–O theory. Thermal-cycling measurements were conducted at different temperatures, and good reliability and repeatability were confirmed. In addition, an obvious optical heating effect was also realized and the variation of temperature induced with a laser was about 32 K. These results reveal that KLN:xEr3+/Yb3+ submicroparticles with high sensor sensitivity and an obvious laser-induced thermal effect are suitable for future optical thermometers and optical heaters.

Ni catalysts supported on nanosheet (S) and nanoplate (P) γ-Al 2 O 3 have been successfully synthesized for carbon dioxide (CO 2 ) reforming of methane. The Ni/Al 2 O 3 -S catalyst possessed excellent activity and stability whereas the Ni/Al 2 O 3 -P catalyst exhibited slightly lower activity and much worse stability. The Ni/Al 2 O 3 -S catalyst displayed much smaller size of Ni nanoparticles, which may explain the difference in activity. The Ni/Al 2 O 3 -S catalyst possessed enhanced anti-sintering and anti-coke properties, which would lead to an improved stability.

Intracellular accumulation of abnormally phosphorylated tau in different types of neurons is a pathological characteristic of Alzheimer’s disease (AD). While tau modification and associated neuronal loss and hypometabolism start in the entorhinal cortex (EC) in early AD patients, the mechanism by which mutant P301L hTau leads to dementia is not fully elucidated. Here, we studied the effects of P301L hTau transduction in the medial EC (MEC) of mice on tau phosphorylation and accumulation, and cognitive deficit. We found that the exogenous mutant tau protein was restricted in MEC without spreading to other brain regions at one month after transduction. Interestingly, expression of the mutant tau in MEC induces endogenous tau hyperphosphorylation and accumulation in hippocampus and cortex, and inhibits neuronal activity with attenuated PP-DG synapse plasticity, leading to hippocampus-dependent memory deficit with intact olfactory function. These findings suggest a novel neuropathological mechanism of early AD, which is initiated by tau accumulation in MEC, and demonstrate a tau pathological model of early stage AD.

Band gap opening and engineering make up one of the primary goals of developing novel materials for photocatalytic hydrogen generation. We report here a facile synthesis of graphene decorated with in-plane boron nitride domains via control of both the doping sequence of heteroatoms and the oxygen content of the graphene precursor, showing significant differences in the doping pattern compared with B and/or N singly doped or co-doped graphene. We uncover that the formation of BN domains in graphene is critical for engineering the band gap and delivering an improved activity for photocatalytic hydrogen generation in the absence of any photosensitizer. This work paves the way for the rational design and construction of graphene-based photocatalysts for efficient photocatalysis.

Overexpressing Tau counteracts apoptosis and increases dephosphorylated β-catenin levels, but the underlying mechanisms are elusive. Here, we show that Tau can directly and robustly acetylate β-catenin at K49 in a concentration-, time-, and pH-dependent manner. β-catenin K49 acetylation inhibits its phosphorylation and its ubiquitination-associated proteolysis, thus increasing β-catenin protein levels. K49 acetylation further promotes nuclear translocation and the transcriptional activity of β-catenin, and increases the expression of survival-promoting genes (bcl2 and survivin), counteracting apoptosis. Mutation of Tau's acetyltransferase domain or co-expressing non-acetylatable β-catenin-K49R prevents increased β-catenin signaling and abolishes the anti-apoptotic function of Tau. Our data reveal that Tau preserves β-catenin by acetylating K49, and upregulated β-catenin/survival signaling in turn mediates the anti-apoptotic effect of Tau.

Long-range electron transfer in proteins can be rationalized as a sequential short-distance electron-hopping processes via amino acid residues having low ionization energy as relay stations. Tyrosine residues can serve as such redox-active intermediates through one-electron oxidation to form a π-radical cation at its phenol side chain. An electron transfer from a vicinal functional group to this π-electron hole completes an elementary step of charge migration. However, transient oxidized/reduced intermediates formed at those relay stations during electron transfer processes have not been observed. In this study, formation of analog reactive intermediates via electron donor–acceptor coupling is observed by using IRMPD action spectroscopy. An elementary charge migration at the molecular level in model tyrosine-containing peptide radical cations [M]˙+ in the gas phase is revealed with its unusual Cα–Cβ bond cleavage at the side chain of the N-terminal residue. This reaction is induced by the radical character of the N-terminal amino group (–NH2˙+) resulting from an n → π+ interaction between the nonbonding electron pair of NH2 (n) and the π-electron hole at the Tyr side chain (π+). The formation of –NH2˙+ is supported by the IRMPD spectrum showing a characteristic NH2 scissor vibration coupled with Tyr side-chain stretches at 1577 cm−1. This n → π+ interaction facilitates a dissociative electron transfer with NH2 as the relay station. The occurrence of this side-chain cleavage may be an indicator of the formation of reactive conformers featuring the n → π+ interaction.

The economic and highly efficient synthesis of γ-valerolactone (GVL) is being increasingly focused due to its wide applications in solvent, chemical, and fuel. Herein, a range of SAPO-34 supported zirconium phosphate (ZPS-X) catalysts were prepared for a facile one-pot conversion of furfural (FF) to GVL through a series of cascaded reactions involving transfer hydrogenation, etherification, alcoholysis and esterification. The introduction of zirconium phosphate renders the formation of relatively strong Lewis acid sites, and the amount of Lewis (L) and Bronsted (B) acid sites of ZPS-X catalysts could be modified by adjusting the molar ratio of Zr to P (Zr/P ratio). Specifically, ZPS-1.0 having an appropriate Zr/P ratio with relatively strong L acid sites exhibited superior activity and selectivity for the production of GVL from FF.

The CuO nanorods (NRs) are prepared with the help of inositol hexakisphosphate which serves as a binding agent and stabilizer. We have successfully fabricated Cu 2 O-decorated palladium networks (Cu 2 O/Pd Networks) by using such CuO NRs as reaction beds. Transmission electron microscopy images show that Cu 2 O/Pd network is composed of small and irregular fused nanoparticles with an average size of about 10 nm. Electrochemical results depict that the as-synthesized catalyst exhibits 2-fold higher activity for methanol oxidation than the commercially available 20% Pd/C catalyst and Pd black catalyst. Furthermore, CO-tolerance is also remarkably enhanced due to the presence of Cu 2 O. Such highly active, low-cost, and superiorly CO-tolerant catalysts of Cu 2 O/Pd Networks will open up a new avenue for direct methanol fuel cells.

The building blocks of the well-defined and easily modified carbon-bond structure of graphene sheet units bring unique characteristics to carbon materials. Especially when these carbon materials are nanosized, their tunable electronic states, giant conjugated structures, oxygen groups on the defects of graphene sheets, and various dopants all help make the materials active in liquid-phase catalytic reactions. In this mini-review, we mainly focus on the liquid-phase reactions catalyzed by carbon nanomaterials, and the related mechanisms are discussed on the basis of their structure fundamentals. In the final section, we also provide our perspectives on this rapidly developing carbocatalysis field.

Metallic nickel nanostructures that were partially decorated by discrete nickel oxide layers were fabricated by in situ reduction of calcinated Ni-containing layered double hydroxide nanosheets, the structure of which was confirmed by extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The existence of the abundant interfaces between the surface Ni oxide overlayer and metallic Ni altered the geometric/electronic structure of the Ni nanoparticles, making them apt for CO activation under light irradiation. Most importantly, the unique structure favors the C-C coupling reaction on its surface, which confers the catalyst unexpected reaction power towards higher hydrocarbons at moderate reaction conditions. This study leads to a green and sustainable approach for the photocatalytic production of highly valuable chemical fuels.

Extracellular accumulation of amyloid-β (Aβ) forming senile plaques is one of the hallmark pathologies in Alzheimer's disease (AD), while the mechanisms underlying the neuronal toxic effect of Aβ are not fully understood. Here, we found that intracerebroventricular infusion of the aged Aβ42 in mice only induces memory deficit at 24 h but not at 7 days. Interestingly, a remarkably increased CREB (cAMP response element-binding protein) Ser133-phosphorylation (pS133-CREB) with microglial activation was detected at 24 h but not at 7 days after Aβ infusion. Aβ treatment for 24 h increased pS133-CREB level in microglia of the hippocampal non-granular cell layers with remarkably decreased pS133-CREB immunoreactivity in neurons of the hippocampal granular cell layers, including CA1, CA3, and DG subsets. Inhibition of microglia activation by minocycline or CREB phosphorylation by H89, an inhibitor of protein kinase A (PKA), abolished Aβ-induced microglia CREB hyperphosphorylation with restoration of neuronal function and attenuation of inflammatory response, i.e., reduced levels of interleukin-6 (IL6) and pCREB binding of matrix metalloproteinase-9 (MMP9) DNA. Finally, treatment of the primary hippocampal neurons with Aβ-potentiated microglia media decreased neuronal GluN1 and GluA2 levels, while simultaneous inhibition of PKA restored the levels. These novel findings reveal that intracerebroventricular infusion of Aβ only induces transient memory deficit in mice and the molecular mechanisms involve a stimulated microglial CREB phosphorylation.

Conversion of syngas (CO, H2 ) to hydrocarbons, commonly known as the Fischer-Tropsch (FT) synthesis, represents a fundamental pillar in today's chemical industry and is typically carried out under technically demanding conditions (1-3 MPa, 300-400 °C). Photocatalysis using sunlight offers an alternative and potentially more sustainable approach for the transformation of small molecules (H2 O, CO, CO2 , N2 , etc.) to high-valuable products, including hydrocarbons. Herein, a novel series of Fe-based heterostructured photocatalysts (Fe-x) is successfully fabricated via H2 reduction of ZnFeAl-layered double hydroxide (LDH) nanosheets at temperatures (x) in the range 300-650 °C. At a reduction temperature of 500 °C, the heterostructured photocatalyst formed (Fe-500) consists of Fe0 and FeOx nanoparticles supported by ZnO and amorphous Al2 O3 . Fe-500 demonstrates remarkable CO hydrogenation performance with very high initial selectivities toward hydrocarbons (89%) and especially light olefins (42%), and a very low selectivity towards CO2 (11%). The intimate and abundant interfacial contacts between metallic Fe0 and FeOx in the Fe-500 photocatalyst underpins its outstanding photocatalytic performance. The photocatalytic production of high-value light olefins with suppressed CO2 selectivity from CO hydrogenation is demonstrated here.

The transient receptor potential cation (TRPC) channels are widely expressed in nervous system but their functions remain largely unclear. Here, we found that TRPC1 deletion did not affect learning and memory in physiological conditions, while it aggravated learning and memory deficits induced by amyloid-β (Aβ), the major component of the senile plaques observed in the brains of Alzheimer's disease (AD). Further studies demonstrated that TRPC1 deletion did not affect cell apoptosis in physiological condition, but it exacerbated the Aβ-induced cell death in mouse hippocampus. Moreover, the level of TRPC1 was decreased in AD cell and mouse models, and upregulation of TRPC1 decreased Aβ levels with attenuation of apoptosis in the cells stably overexpressing amyloid-β protein precursor (AβPP). Finally, the transmembrane domain of TRPC1 could bind to AβPP and thus decreased Aβ production. These findings indicate that loss of TRPC1 exacerbates Aβ-induced memory deficit and cell apoptosis, though it does not impair cognitive function or induce cell death in physiological conditions.

Two polysaccharides were isolated from the stroma of cultured Cordyceps kyushuensis by hot water extraction as well as ion-exchange and gel-permeation chromatography. The fourier transform infrared (FTIR) spectra revealed the general characteristic absorption peaks of polysaccharides. Preliminary structural characterizations were conducted by NMR and physicochemical property, whereas their total sugar, sulfate acid and uronic acid contents, molecular weights and monosaccharide compositions were significantly different. Antioxidant properties were evaluated by assays of various antioxidant in vitro systems. The results showed that the two polysaccharides possessed good antioxidant properties in a concentration-dependent manner, especially scavenging abilities on hydroxyl radicals. Both samples showed clearly and strong capacity on protective effect of DNA damage. With current findings, the polysaccharides from C. kyushuensis may have potential applications in health functional food.

We successfully synthesized a dandelion-like PtPd heterogeneous structure via a facile one-pot hydrothermal route by reducing Na 2 PdCl 4 and H 2 PtCl 6 with ascorbic acid in the presence of hexadecylpyridinium chloride monohydrate. Hexadecylpyridinium chloride monohydrate acted as the shape-directing agent, which is critical to the reproducible formation of dandelion-like PtPd nanoclusters (DPtPdNC). The prepared DPtPdNC with an average diameter of 40 nm composed of dozens of branched arm assembled by Pt and Pd heterogeneous nanoseeds. DPtPdNC had a strong electron-electron interaction. What's more, there were numerous nanoscale steps, kinks and edges in DPtPdNC open channel structure. As a result, an optimized DPtPdNC made by fine-tuning ratio of the Pt (7%) and Pd (93%) showed hugely active surface sites and a superior electrocatalytic performance for ethanol oxidation was well as a long durability.

ssDNA was employed to readily disperse reduced graphene oxide (RGO) to form ssDNA–RGO composites, which could be used as a superior support to expediently electrodeposit Pt to synthesize ssDNA–RGO/cotton-flower-like-Pt nanocomposites (ssDNA–RGO/cf-Pt). The formation of cotton-flower-like-Pt clusters was due to the assistance of nitrogen atoms and phosphate groups in ssDNA. The catalytic activity of the ssDNA–RGO/cf-Pt nanocomposite for methanol oxidation was 2.5 fold of RGO/Pt and 3.8 fold of commercial Pt NPs. The outstanding catalytic activity of this novel catalyst was attributed to the very large surface of the highly conductive ssDNA–RGO and cotton-flower-like-Pt clusters with an open structure. The latter was beneficial for mass transfer. In addition, the excellent ability of the ssDNA–RGO/cf-Pt nanocomposite against CO poisoning was found and the anti-poisoning ratio (If/Ib) of ssDNA–RGO/cf-Pt was 1.75 fold larger than those of RGO/Pt and commercial Pt NPs. The elevated oxidation of CO in the adsorption state may be due to ssDNA providing abundant oxygen groups as well as the residual oxygen species in the RGO. A possible mechanism for the improved catalytic activity and CO tolerance was deduced according to UV-visible, Raman, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) results.

Cellulase and mannanase are both important enzyme additives in animal feeds. Expressing the two enzymes simultaneously within one microbial host could potentially lead to cost reductions in the feeding of animals. For this purpose, we codon-optimized the Aspergillus niger Man5A gene to the codon-usage bias of Trichoderma reesei. By comparing the free energies and the local structures of the nucleotide sequences, one optimized sequence was finally selected and transformed into the T. reesei pyridine-auxotrophic strain TU-6. The codon-optimized gene was expressed to a higher level than the original one. Further expressing the codon-optimized gene in a mutated T. reesei strain through fed-batch cultivation resulted in coproduction of cellulase and mannanase up to 1376 U·mL

A one-step ligand-free method based on an adsorption-precipitation process was developed to fabricate iridium/cerium oxide (Ir/CeO2 ) nanocatalysts. Ir species demonstrated a strong metal-support interaction (SMSI) with the CeO2 substrate. The chemical state of Ir could be finely tuned by altering the loading of the metal. In the carbon dioxide (CO2 ) hydrogenation reaction it was shown that the chemical state of Ir species-induced by a SMSI-has a major impact on the reaction selectivity. Direct evidence is provided indicating that a single-site catalyst is not a prerequisite for inhibition of methanation and sole production of carbon monoxide (CO) in CO2 hydrogenation. Instead, modulation of the chemical state of metal species by a strong metal-support interaction is more important for regulation of the observed selectivity (metallic Ir particles select for methane while partially oxidized Ir species select for CO production). The study provides insight into heterogeneous catalysts at nano, sub-nano, and atomic scales.

The building blocks of the well-defined and easily modified carbon-bond structure of graphene sheet units bring unique characteristics to carbon materials. Especially when these carbon materials are nanosized, their tunable electronic states, giant conjugated structures, oxygen groups on the defects of graphene sheets, and various dopants all help make the materials active in liquid-phase catalytic reactions. In this mini-review, we mainly focus on the liquid-phase reactions catalyzed by carbon nanomaterials, and the related mechanisms are discussed on the basis of their structure fundamentals. In the final section, we also provide our perspectives on this rapidly developing carbocatalysis field.

Zn- and Na-modulated Fe catalysts were fabricated by a simple coprecipitation/washing method. Zn greatly changed the size of iron species, serving as the structural promoter, while the existence of Na on the surface of the Fe catalyst alters the electronic structure, making the catalyst very active for CO activation. Most importantly, the electronic structure of the catalyst surface suppresses the hydrogenation of double bonds and promotes desorption of products, which renders the catalyst unexpectedly reactive toward alkenes-especially C5+ alkenes (with more than 50% selectivity in hydrocarbons)-while lowering the selectivity for undesired products. This study enriches C1 chemistry and the design of highly selective new catalysts for high-value chemicals.

Alzheimer's disease (AD) is characterized by profound synapse loss and impairments of learning and memory. Magnesium affects many biochemical mechanisms that are vital for neuronal properties and synaptic plasticity. Recent studies have demonstrated that the serum and brain magnesium levels are decreased in AD patients; however, the exact role of magnesium in AD pathogenesis remains unclear. Here, we found that the intraperitoneal administration of magnesium sulfate increased the brain magnesium levels and protected learning and memory capacities in streptozotocin-induced sporadic AD model rats. We also found that magnesium sulfate reversed impairments in long-term potentiation (LTP), dendritic abnormalities, and the impaired recruitment of synaptic proteins. Magnesium sulfate treatment also decreased tau hyperphosphorylation by increasing the inhibitory phosphorylation of GSK-3β at serine 9, thereby increasing the activity of Akt at Ser473 and PI3K at Tyr458/199, and improving insulin sensitivity. We conclude that magnesium treatment protects cognitive function and synaptic plasticity by inhibiting GSK-3β in sporadic AD model rats, which suggests a potential role for magnesium in AD therapy.

Naked magnetically recyclable mesoporous Au–γ-Fe2O3 clusters, combining the inherent magnetic properties of γ-Fe2O3 and the high catalytic activity of Au nanoparticles (NPs), are successfully synthesized. Hydrophobic Au–Fe3O4 dimers are first self-assembled to form sub-micrometer-sized Au–Fe3O4 clusters. The Au–Fe3O4 clusters are then coated with silica, calcined at 550 °C, and finally alkali treated to dissolve the silica shell, yielding naked-Au–γ-Fe2O3 clusters containing Au NPs of size 5–8 nm. The silica protection strategy serves to preserve the mesoporous structure of the clusters, inhibit the phase transformation from γ-Fe2O3 to α-Fe2O3, and prevent cluster aggregation during the synthesis. For the reduction of p-nitrophenol by NaBH4, the activity of the naked-Au–γ-Fe2O3 clusters is ≈22 times higher than that of self-assembled Au–Fe3O4 clusters. Moreover, the naked-Au–γ-Fe2O3 clusters display vastly superior activity for CO oxidation compared with carbon-supported Au–γ-Fe2O3 dimers, due to the intimate interfacial contact between Au and γ-Fe2O3 in the clusters. Following reaction, the naked-Au–γ-Fe2O3 clusters can easily be recovered magnetically and reused in different applications, adding to their versatility. Results suggest that naked-Au–γ-Fe2O3 clusters are a very promising catalytic platform affording high activity. The strategy developed here can easily be adapted to other metal NP–iron oxide systems.