In this study, carbon dioxide is one of the end products of combustion, and is not a benign component of the atmosphere. The concentration of CO2 in the atmosphere has reached unprecedented levels ...and continues to increase owing to an escalating rate of fossil fuel combustion, causing concern about climate change and rising sea levels. In view of the inevitable depletion of fossil fuels, a possible solution to this problem is the recycling of carbon dioxide, possibly captured at its point of generation, to fuels. Researchers in this field are using solar energy for CO2 activation and utilization in several ways: (i) so-called artificial photosynthesis using photo-induced electrons; (ii) bulk electrolysis of a CO2 saturated solution using electricity produced by photovoltaics; (iii) CO2 hydrogenation using solar-produced H2; and (iv) the thermochemical reaction of metal oxides at extremely high temperature reached by solar collectors. Since the thermodynamics of CO2 at high temperature (> 1000 ºC) are quite different from those near room temperature, only chemistry below 200 ºC is discussed in this review.
Resistance to chemotherapy is a major challenge for the treatment of patients with colorectal cancer (CRC). Previous studies have found that microRNAs (miRNAs) play key roles in drug resistance; ...however, the role of miRNA‐373‐3p (miR‐375‐3p) in CRC remains unclear. The current study aimed to explore the potential function of miR‐375‐3p in 5‐fluorouracil (5‐FU) resistance. MicroRNA‐375‐3p was found to be widely downregulated in human CRC cell lines and tissues and to promote the sensitivity of CRC cells to 5‐FU by inducing colon cancer cell apoptosis and cycle arrest and by inhibiting cell growth, migration, and invasion in vitro. Thymidylate synthase (TYMS) was found to be a direct target of miR‐375‐3p, and TYMS knockdown exerted similar effects as miR‐375‐3p overexpression on the CRC cellular response to 5‐FU. Lipid‐coated calcium carbonate nanoparticles (NPs) were designed to cotransport 5‐FU and miR‐375‐3p into cells efficiently and rapidly and to release the drugs in a weakly acidic tumor microenvironment. The therapeutic effect of combined miR‐375 + 5‐FU/NPs was significantly higher than that of the individual treatments in mouse s.c. xenografts derived from HCT116 cells. Our results suggest that restoring miR‐375‐3p levels could be a future novel therapeutic strategy to enhance chemosensitivity to 5‐FU.
Resistance to chemotherapy is a major challenge for the treatment of patients with colorectal cancer (CRC). Our results suggest that the restoration of microRNA‐375‐3p levels could be a future novel therapeutic strategy to modulate and enhance chemosensitivity to 5‐fluorouracil treatment in CRC.
With the rapid development of information technology, online learning of legal specialty in the era of artificial intelligence has become a significant trend. This study explores the pedagogical ...reform path of integrating course ideology into online learning for law majors. Multiple linear regression models and Apriori association rule algorithms were used to analyze the learning effects of 457 law students. The integration of the course Civics and Politics significantly impacted students’ learning outcomes, especially showing significant differences among students of different genders and grades. Different genders showed significant differences (p<0.05) in course teaching integration and faculty. Significant differences were also observed among students of various grades regarding integration of course materials, teaching, and teacher team integration. The Pearson product-difference correlation analysis of the variables of course civics integration into law teaching found that talent cultivation goal integration, course textbook integration, course teaching integration, and teacher team had significant positive correlations with learning outcomes. These findings were further validated by the association rules mined by the Apriori algorithm. The student learning outcomes are more likely to achieve excellence when the scores for course material integration and teaching integration are high. This study provides an effective pedagogical reform path for integrating civics into online learning for law majors, which significantly enhances students’ learning effects.
Outstanding electrocatalysts for high‐efficiency water splitting demand not only the high intrinsic activity determined by the electronic structure but also a favorable mass transfer (electrolyte ...diffusion and bubble desorption) and strong structural stability. Here, a 3D core–shell electrocatalyst consisting of Co(OH)2 cavity array‐encapsulated NiMo alloy on the flexible carbon cloth substrate (Co(OH)2/NiMo CA@CC) is proposed. Density functional theory reveals that coupling NiMo with Co(OH)2 can better optimize the water adsorption/dissociation and hydrogen adsorption energies in hydrogen evolution reaction, and also accelerate the kinetics of oxygen evolution reaction. Based on this, the open porous structure of the outer Co(OH)2 cavity array further promotes the diffusion of the electrolyte into the heterogeneous interface between NiMo and Co(OH)2, significantly shortening the electron transfer pathways and exposing multiple active sites. In addition, the macroporous array structure accelerates the bubble evolution and desorption process, thus ensuring a rapid mass transfer. When served as bifunctional electrocatalysts toward alkaline overall water splitting, Co(OH)2/NiMo CA@CC delivers a current density of 10 mA cm−2 at a low cell voltage of 1.52 V. Results support the multiscale optimization of the surface/interface engineering induced by the macroporous array.
A macroporous Co(OH)2/NiMo self‐supporting electrode possesses the superb performance of overall water splitting. The open Co(OH)2 cavity array deepens the diffusion of electrolyte at the heterogeneous interface, which significantly shortens the electron transport pathways and enables rapid removal of the gas bubble. Moreover, adequate exposure of the interface achieves interfacial charge modulation to facilitate the reaction kinetics.
Urea-formaldehyde (UF) resin is one of the most widely used adhesives in wood-based composites. The major concerns of the resin utilization are free formaldehyde release and poor water resistance. In ...this study, based on life cycle assessment (LCA) analysis, a “greener” adhesive composed of UF resin and cottonseed meal was successfully prepared via a common synthetic process of pure UF resins. The raw materials (urea and formaldehyde) of UF resins were replaced by cottonseed meal with up to 40% on weight basis. The effect of the cottonseed meal on the rheological property, mechanical strength, chemical structure, thermal stability, and glue line features of these “greener” adhesives was investigated. The adhesive showed an improved mechanical strength as compared to pure UF resins in the tensile shear strength of bonded wood specimens, especially on the water soaked strength. It also showed similar chemical structures, thermal stabilities, and even better rheological properties than pure UF resins. Cottonseed meal resulted in good dispersions in these adhesives with up to 30% portion. It acted as a reinforcement for the adhesive other than a filler or an additive. This “greener” adhesive improved the performance of pure UF resins while retained its outstanding features, suggesting the feasibility of using it as UF resins in current manufacturing lines for wood-based composites is there.
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•“Greener” adhesives composed of UF resin and cottonseed meal were formulated via a typical UF resin synthetic process.•Raw chemical materials in pure UF resin could be replaced by cottonseed meal with up to 40% on weight basis.•The “greener” adhesive shows better performance than UF resin in aspects of water resistance, rheological properties, etc.•These “greener” adhesives are suitable, at least, for replacing UF resins in wood-based composites manufacturing while retaining its low cost.
Methane is the main component of natural gas and shale gas. It is chemically stable, and its activation often requires high temperatures, which lead to its extensive transformation into undesirable ...products such as CO and CO2. Thus, the development of efficient catalysts for the selective transformation of methane represents a substantial challenge. In this work, we synthesized La2O2CO3 samples with different morphologies (rod- and plate-shapes) at the nanometer scale. We observed that one of the rod-shaped samples exhibited the best catalytic properties among the investigated samples in the oxidative coupling of methane (OCM) at low temperatures (420–500 °C); in addition, its specific activity was 20 times greater than that of any of the other rod-shaped samples. This difference corresponded to the O2-TPD results and was attributed to the crystallographic facets exposed. Among the exposed facets, the (110), (12̅0), and (21̅0) facets had relatively loose atomic configurations that increased the conversion of methane in the OCM. Moreover, these facets were beneficial to the formation of the chemisorbed oxygen species and their moderately basic sites, which improve the selectivity in the OCM.
Reversible H2 storage near room temperature and pressure with pH as the “switch” for controlling the direction of the reaction has been demonstrated (Nat. Chem., 2012, 4, 383–388). Several ...bioinspired “proton-responsive” mononuclear Ir(III) catalysts for CO2 hydrogenation were prepared to gain mechanistic insight through investigation of the factors that control the effective generation of formate. These factors include (1) kinetic isotope effects by water, hydrogen, and bicarbonate; (2) position and number of hydroxyl groups on bpy-type ligands; and (3) mono- vs dinuclear iridium complexes. We have, for the first time, obtained clear evidence from kinetic isotope effects and computational studies of the involvement of a water molecule in the rate-determining heterolysis of H2 and accelerated proton transfer by formation of a water bridge in CO2 hydrogenation catalyzed by bioinspired complexes bearing a pendent base. Furthermore, contrary to expectations, a more significant enhancement of the catalytic activity was observed from electron donation by the ligand than on the number of the active metal centers.
Senescence and altered differentiation potential of bone marrow stromal cells (BMSCs) lead to age‐related bone loss. As an important posttranscriptional regulatory pathway, alternative splicing (AS) ...regulates the diversity of gene expression and has been linked to induction of cellular senescence. However, the role of splicing factors in BMSCs during aging remains poorly defined. Herein, we found that the expression of the splicing factor Y‐box binding protein 1 (YBX1) in BMSCs decreased with aging in mice and humans. YBX1 deficiency resulted in mis‐splicing in genes linked to BMSC osteogenic differentiation and senescence, such as Fn1, Nrp2, Sirt2, Sp7, and Spp1, thus contributing to BMSC senescence and differentiation shift during aging. Deletion of Ybx1 in BMSCs accelerated bone loss in mice, while its overexpression stimulated bone formation. Finally, we identified a small compound, sciadopitysin, which attenuated the degradation of YBX1 and bone loss in old mice. Our study demonstrated that YBX1 governs cell fate of BMSCs via fine control of RNA splicing and provides a potential therapeutic target for age‐related osteoporosis.
Synopsis
Alternative splicing has been shown to regulate cellular senescence and differentiation. This study links the reduced expression of the splicing regulator YBX1 in aging bone marrow stromal cells to senescence and aging‐related bone loss.
The expression level of YBX1 in BMSCs decreases during aging.
Ybx1 overexpression in BMSCs stimulates bone formation, while its deletion accelerates bone loss.
YBX1 suppresses BMSC senescence and modulates BMSC differentiation by controlling RNA splicing.
The small compound sciadopitysin attenuates YBX1 degradation and bone loss in old mice.
Reduced expression of YBX1 in aging bone marrow stromal cells induces their senescence and bone loss due to mRNA mis‐splicing.
The catalytic cycle for the production of formic acid by CO2 hydrogenation and the reverse reaction have received renewed attention because they are viewed as offering a viable scheme for hydrogen ...storage and release. In this Forum Article, CO2 hydrogenation catalyzed by iridium complexes bearing sophisticated N^N-bidentate ligands is reported. We describe how a ligand containing hydroxy groups as proton-responsive substituents enhances the catalytic performance by an electronic effect of the oxyanions and a pendent-base effect through secondary coordination sphere interactions. In particular, (Cp*IrCl)2(TH2BPM)Cl2 (Cp* = pentamethylcyclopentadienyl; TH2BPM = 4,4′,6,6′-tetrahydroxy-2,2′-bipyrimidine) enormously promotes the catalytic hydrogenation of CO2 in basic water by these synergistic effects under atmospheric pressure and at room temperature. Additionally, newly designed complexes with azole-type ligands were applied to CO2 hydrogenation. The catalytic efficiencies of the azole-type complexes were much higher than that of the unsubstituted bipyridine complex Cp*Ir(bpy)(OH2)SO4. Furthermore, the introduction of one or more hydroxy groups into ligands such as 2-pyrazolyl-6-hydroxypyridine, 2-pyrazolyl-4,6-dihydroxypyrimidine, and 4-pyrazolyl-2,6-dihydroxypyrimidine enhanced the catalytic activity. It is clear that the incorporation of additional electron-donating functionalities into proton-responsive azole-type ligands is effective for promoting further enhanced hydrogenation of CO2.
As a widely used approach to modify a material's bulk properties, doping can effectively improve electrochemical properties and structural stability of various cathodes for rechargeable batteries, ...which usually empirically favors a uniform distribution of dopants. It is reported that dopant aggregation effectively boosts the cyclability of a Mg‐doped P2‐type layered cathode (Na0.67Ni0.33Mn0.67O2). Experimental characterization and calculation consistently reveal that randomly distributed Mg dopants tend to segregate into the Na‐layer during high‐voltage cycling, leading to the formation of high‐density precipitates. Intriguingly, such Mg‐enriched precipitates, acting as 3D network pillars, can further enhance a material's mechanical strength, suppress cracking, and consequently benefit cyclability. This work not only deepens the understanding on dopant evolution but also offers a conceptually new approach by utilizing precipitation strengthening design to counter cracking related degradation and improve high‐voltage cyclability of layered cathodes.
Improved cyclability of Mg‐doped P2‐NMM layered cathode is mainly due to suppression of cracking. Randomly distributed Mg dopants tend to segregate into precipitates during high‐voltage cycling, which can further strengthen the layered cathode and suppress cracking, leading to superior cycling stability at elevated voltage. Dopant precipitate is a new design concept to improve layered cathode cyclability.
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