The catalytic activity of Au-embedded graphene is investigated by the first-principle method using the CO oxidation as a benchmark probe. The first step of CO oxidation catalyzed by the Au-embedded ...graphene is most likely to proceed with the Langmuir−Hinshelwood reaction (CO + O2 → OOCO → CO2 +O), and the energy barrier is as low as 0.31 eV. The second step of the oxidation would be the Eley−Rideal reaction (CO + O → CO2) with a much smaller energy barrier (0.18 eV). The partially filled d states of Au are localized around the Fermi level due to the interactions between Au and the neighboring carbon atoms. The high activity of Au-embedded graphene may be attributed to the electronic resonance among electronic states of CO, O2, and the Au atom, particularly, among the d states of the Au atom and the antibonding 2π* states of CO and O2. This opens a new avenue to fabricate low cost and high activity carbon-based catalyst.
Rice is the staple food for more than half of the world＇s population and for more than 60% of China population. Increasing rice yield is therefore crucial for solving food shortage problem, ensuring ...food secruity, and reducing poverty. Given the vast population and limited per capita cultivated land in China, meeting food demands by increasing the yield per unit area with the aid of advanced sciences and technologies would be the only option. Several alternative measures for increasing crop yield, such as building water conservancy facilities, increasing fertilizer application, improving soil texture, forming interrelated cultivation techniques, more effective controlling of pests and diseases, and using of elite varieties, have been undertaken. Among these alternative measures, adopting elite varieties, particularly popularizing super hybrid rice, proves to be the most economical and effective option.
We herein propose a bioengineering approach where bacterial outer membrane vesicles (OMVs) were coated on drug-loaded polymeric micelles to generate an innovative nanomedicine for effective cancer ...immunotherapy and metastasis prevention. Whereas OMVs could activate the host immune response for cancer immunotherapy, the loaded drug within polymeric micelles would exert both chemotherapeutic and immunomodulatory roles to sensitize cancer cells to cytotoxic T lymphocytes (CTLs) and to kill cancer cells directly. We demonstrated that the systemic injection of such a bioinspired immunotherapeutic agent would not only provide effective protective immunity against melanoma occurrence but also significantly inhibited tumor growth in vivo and extended the survival rate of melanoma mice. Importantly, the nanomedicine could also effectively inhibit tumor metastasis to the lung. The bioinspired immunomodulatory nanomedicine we have developed repurposes the bacterial-based formulation for cancer immunotherapy, which also defines a useful bioengineering strategy to the improve current cancer immunotherapeutic agents and delivery systems.
{111}-Dominated octahedral Co3O4 electrocatalyst with better adsorption performance and enhanced electron transfer exhibited good catalytic activity and high selectivity for glycerol oxidation to ...high-value-added chemical, i.e., dihydroxyacetone (DHA).
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•Successful synthesis of the {111}- and {001}-dominant Co3O4 electrodes.•First report of crystal engineering for the oxidation of glycerol using spinnel cobalt oxide (Co3O4).•{111}-dominant octahedral Co3O4 plane exhibits superior activity for glycerol oxidation.•Improved reactant adsorption, and charge transfer across distinct Co3O4 facets all affect activity.
To further explore the electrooxidation mechanism of biomass-based compounds, it is highly desirable to regulate the proportion of reactive facets and identify facet-governing reactivity through crystal facet engineering. In this study, octahedral and cubic cobalt spinel oxide (Co3O4), each exclusively exposed by one specific type of facet, are selected as two representative microstructure models for tuning the selectivity and productivity of electrochemical glycerol oxidation reaction. The results indicate that the {111}-dominant octahedral Co3O4 plane with a higher population of Co2+ sites exhibits superior electrocatalytic activity for glycerol oxidation compared with the {001}-dominant cubic Co3O4, allowing nearly 65% of glycerol to be converted into a high-value-added dihydroxyacetone (DHA) compound. The average DHA production rate over octahedral Co3O4 (2.5 μmol cm−2h−1) are approximately 3.5 times greater than that over cubic Co3O4 (0.7 μmol cm−2h−1). Electrochemical studies and surface atomic configuration analysis reveal that {111}-dominant octahedral Co3O4 with a higher density of active cobalt ion yields unique reactant adsorption and charge transfer, leading to increased glycerol oxidation reactivity and productivity. The present study emphasizes the significance of controlling the highly active facet in developing efficient and selective electrocatalysts.
The most important issue for the clinical application of sarcopenic obesity (SO) is the lack of a consensus definition. The aim of the present study was to determine the best measurement for SO by ...estimating the association between various definitions and the risk of falls and metabolic syndrome (MS). We studied a community of 765 adults aged 65 years and older in 2015-2017. Sarcopenia obesity was measured by sarcopenia (defined by low muscle mass with either low handgrip strength or low gait speed or both) plus obesity (defined by waist circumference, body fat percentage and BMI). The MS was defined according to the National Cholesterol Education Program ATP III. Logistic regression models were constructed to examine the relationships between sarcopenia obesity and risk of fall and MS. In the analysis of the fall risk with SO defined by waist circumference, the participants with non-sarcopenia/non-obesity were treated as the reference group. The OR to fall in participants with SO was 10·16 (95 % CI 2·71, 38·13) after adjusting for confounding covariates. In the analysis of the risk of the MS between participants with individual components of sarcopenia coupled with obesity defined by waist circumference, the risk was statistically significant for low gait speed (OR: 7·19; 95 % CI 3·61, 14·30) and low grip strength (OR: 9·19; 95 % CI 5·00, 16·91). A combination of low grip strength and abdominal obesity for identifying SO may be a more precise and practical method for predicting target populations with unfavourable health risks, such as falls risk and MS.
Circular RNAs (circRNAs) have been shown to interact with microRNAs (miRNA) as competitive endogenous RNAs (ceRNAs) to regulate target gene expression and participate in tumorigenesis. However, the ...role of circRNA-mediated ceRNAs in bladder cancer (BC) remains unknown. Accordingly, the aim of this study was to elucidate the regulatory mechanisms in BC based on construction of the ceRNA network.
The RNA expression profiles were obtained from public datasets in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database, and were used to establish a circRNA-miRNA-mRNA network. The interactions among proteins were analyzed using the STRING database and hubgenes were extracted using the cytoHubba application. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of differentially expressed mRNAs in BC and normal tissue samples were performed to determine the functions of the intersecting mRNAs.
A total of 27 circRNAs, 76 miRNAs, and 4744 mRNAs were found to be differentially expressed between BC and normal tissues. The circRNA-miRNA-mRNA ceRNA network was established based on 21 circRNAs, 14 miRNAs, and 150 mRNAs differentially expressed in BC. We also established a protein-protein interaction network and identified 10 hubgenes, which were used to construct circRNA-miRNA-hubgene regulatory modules. The most enriched biological process GO term was strand displacement (P<0.05), and the homologous recombination and Fanconi anemia pathways were significantly enriched (P<0.05) for the differentially expressed genes in BC.
We screened several dysregulated circRNAs and established a circRNA-associated ceRNA network by bioinformatics analysis. The identified ceRNAs are likely critical in the pathogenesis of BC and may serve as future therapeutic biomarkers.
An unprecedented photoredox‐catalyzed phosphine‐mediated deoxygenation of hexafluoroacetone hydrate was established to accomplish the hydroxylpolyfluoroalkylation of electron‐deficient alkenes. A ...range of bis(trifluoromethyl)carbinols were facilely accessed by using readily available hexafluoroacetone hydrate, instead of toxic gaseous hexafluoroacetone. A range of electron‐deficient alkenes are tolerated, giving the corresponding hydro‐hydroxylpolyfluoroalkylated products in moderate to high yields. Remarkable features of this synthetic strategy include operational simplicity, mild reaction conditions, excellent regioselectivity, and broad functional group tolerance. The success of this strategy relies on the delicate utilization of aldehyde/ketone‐gem‐diol intrinsic equilibrium, which offers an innovated open‐shell pathway for the assembly of synthetically challenging polyfluoroalkylated scaffolds.
The hydroxypolyfluoroalkylation of alkenes is reported, wherein the intrinsic aldehyde/ketone‐gem‐diol equilibrium and photocatalytic phosphine‐mediated deoxygenation play key roles. A range of electron‐deficient alkenes are compatible in this transformation, thus leading to structurally varied bis(trifluoromethyl)carbinols in moderate to excellent yields.
The homeostatic link between oxidative stress and autophagy plays an important role in cellular responses to a wide variety of physiological and pathological conditions. However, the regulatory ...pathway and outcomes remain incompletely understood. Here, we show that reactive oxygen species (ROS) function as signaling molecules that regulate autophagy through ataxia‐telangiectasia mutated (ATM) and cell cycle checkpoint kinase 2 (CHK2), a DNA damage response (DDR) pathway activated during metabolic and hypoxic stress. We report that CHK2 binds to and phosphorylates Beclin 1 at Ser90/Ser93, thereby impairing Beclin 1‐Bcl‐2 autophagy‐regulatory complex formation in a ROS‐dependent fashion. We further demonstrate that CHK2‐mediated autophagy has an unexpected role in reducing ROS levels via the removal of damaged mitochondria, which is required for cell survival under stress conditions. Finally, CHK2−/− mice display aggravated infarct phenotypes and reduced Beclin 1 p‐Ser90/Ser93 in a cerebral stroke model, suggesting an in vivo role of CHK2‐induced autophagy in cell survival. Taken together, these results indicate that the ROS‐ATM‐CHK2‐Beclin 1‐autophagy axis serves as a physiological adaptation pathway that protects cells exposed to pathological conditions from stress‐induced tissue damage.
Synopsis
Whether hypoxia and nutrient starvation are coupled to cellular autophagy remains unclear. Here, DNA damage response kinases ATM and CHK2 are shown to trigger autophagy in response to reactive oxygen species (ROS) accumulation, suggesting a novel physiological adaptation pathway toward metabolic stress.
Depletion of CHK2 or ATM impairs oxidative stress‐induced autophagy in MEFs.
CHK2 binds and phosphorylates Beclin1 at Ser90/Ser93, suppressing Beclin1‐Bcl‐2 autophagy regulatory complex formation.
CHK2‐induced autophagy limits intracellular ROS levels by clearing damaged mitochondria.
CHK2‐induced autophagy protects against cell death and tissue damage following cerebral ischemia.
ROS accumulation activates protective autophagy to prevent stress‐induced tissue damage.
Significance Butyrylcholinesterase (BChE), a common plasma enzyme, has been known for decades but its real physiological roles are just beginning to emerge. Although BChE eliminates the ...neurotransmitter acetylcholine, it is not vital for locomotion, cognition, or other cholinergic functions. Nevertheless, we now find that circulating BChE has a large impact on aggressive behavior in mice that is attributable to its ability to inactivate ghrelin, a peptide hormone involved in hunger, feeding, and stress. A key observation was decreased fighting among group-housed male mice overexpressing BChE after viral gene transfer. In contrast, BChE knockout mice exhibited increased fighting. These effects mirrored changes in plasma levels of active ghrelin. Controlling them might offer therapeutic potential for certain behavioral disorders.
Ongoing mouse studies of a proposed therapy for cocaine abuse based on viral gene transfer of butyrylcholinesterase (BChE) mutated for accelerated cocaine hydrolysis have yielded surprising effects on aggression. Further investigation has linked these effects to a reduction in circulating ghrelin, driven by BChE at levels ∼100-fold above normal. Tests with human BChE showed ready ghrelin hydrolysis at physiologic concentrations, and multiple low-mass molecular dynamics simulations revealed that ghrelin’s first five residues fit sterically and electrostatically into BChE’s active site. Consistent with in vitro results, male BALB/c mice with high plasma BChE after gene transfer exhibited sharply reduced plasma ghrelin. Unexpectedly, such animals fought less, both spontaneously and in a resident/intruder provocation model. One mutant BChE was found to be deficient in ghrelin hydrolysis. BALB/c mice transduced with this variant retained normal plasma ghrelin levels and did not differ from untreated controls in the aggression model. In contrast, C57BL/6 mice with BChE gene deletion exhibited increased ghrelin and fought more readily than wild-type animals. Collectively, these findings indicate that BChE-catalyzed ghrelin hydrolysis influences mouse aggression and social stress, with potential implications for humans.
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