X-Band e.s.r studies on Mov centres formed by an u.v.-irradiated single crystal of the title compound, (NH4)6[(CHO)2Mo8O28]·2H2O, have been carried our at room temperature.Analyses of the e.s.r. spectra show that there are two different paramagnetic species in the unit cell. One may be resolved superhyperfine lines due to the interaction of the Mov centre with a 1H atom; the other can only be resolved hyperfine lines due to the Mov centre.The spin-Hamiltonian parameters have been rigorously calculated using a least-squares-fitting technique, specially adapted to non-coincident g- and A-tensor systems. The principal values of the g, AMo and AH tensors for the two species, as well as the direction cosines of their principal axes with respect to the reference system, are obtained. The spin density and bond nature of the MoV—O bond are estimated according to the principal values of the A tensors. The results indicate the main component of the ground -state molecular orbital is the atomic orbital 4dxy of the MoV paramagnetic centre. The MoV—O bond is an ionic bond with a covalent component.
The separation of mixed C4 olefins is a highly energy-intensive operation in the chemical industry due to the close boiling points of the unsaturated C4 isomers. In particular, the separation of trans/cis-2-butene is among the most challenging separation processes for geometric isomers and is of prime importance to increase the added value of C4 olefins. In this work, we report a series of isostructural gallate-based metal-organic frameworks (MOFs), namely, M-gallate (M = Ni, Mg, Co), featuring oval-shaped pores, that are ideally suitable for shape-selective separation of trans/cis-2-butene through their differentiation in minimum molecular cross-section size. Significantly, Mg-gallate displays a record high trans/cis-2-butene uptake selectivity of 3.19 at 298 K, 1.0 bar in single-component adsorption isotherms. These gallate-based MOFs not only exhibit the highest selectivity for trans/cis-2-butene separation but also accomplish a highly efficient separation of 1,3-butadiene, 1-butene, and iso-butene. DFT-D study shows that Mg-gallate interacts strongly with trans-2-butene and 1,3-butadiene along with short distances of C···H-O cooperative supramolecular interaction of 2.57-2.83 and 2.45-2.79 Å, respectively. In breakthrough experiments, Mg-gallate not only displays prominent separation performance for trans/cis-2-butene but also realizes the clean separation of a ternary mixture of 1,3-butadiene/1-butene/iso-butene and a binary mixture of 1-butene/iso-butene. This work indicates that M-gallate are industrially promising materials for adsorption separation of geometric isomers of C4 hydrocarbons.
Abstract Atherosclerosis is a chronic inflammatory disease characterized with innate and adaptive immunity but also involves pyroptosis. Few studies have explored the role of pyroptosis in advanced atherosclerotic plaques from different vascular beds. Here we try to identify the different underlying function of pyroptosis in the progression of atherosclerosis between carotid arteries and femoral. arteries. We extracted gene expression levels from 55 advanced carotid or femoral atherosclerotic plaques. The pyroptosis score of each sample was calculated by single-sample-gene-set enrichment analysis (ssGSEA). We then divided the samples into two clusters: high pyroptosis scores cluster (PyroptosisScoreH cluster) and low pyroptosis scores cluster (PyroptosisScoreL cluster), and assessed functional enrichment and immune cell infiltration in the two clusters. Key pyroptosis related genes were identified by the intersection between results of Cytoscape and LASSO (Least Absolute Shrinkage and Selection Operator) regression analysis. Finally, all key pyroptosis related genes were validated in vitro. We found all but one of the 29 carotid plaque samples belonged to the PyroptosisScoreH cluster and the majority (19 out of 26) of femoral plaques were part of the PyroptosisScoreL cluster. Atheromatous plaque samples in the PyroptosisScoreL cluster had higher proportions of gamma delta T cells, M2 macrophages, myeloid dendritic cells (DCs), and cytotoxic lymphocytes (CTLs), but lower proportions of endothelial cells (ECs). Immune full-activation pathways (e.g., NOD-like receptor signaling pathway and NF-kappa B signaling pathway) were highly enriched in the PyroptosisScoreH cluster. The key pyroptosis related genes GSDMD, CASP1, NLRC4, AIM2, and IL18 were upregulated in advanced carotid atherosclerotic plaques. We concluded that compared to advanced femoral atheromatous plaques, advanced carotid atheromatous plaques were of higher grade of pyroptosis. GSDMD, CASP1, NLRC4, AIM2, and IL18 were the key pyroptosis related genes, which might provide a new sight in the prevention of fatal strokes in advanced carotid atherosclerosis.
As an emerging micropollutant, p-arsanilic acid (p-ASA) would release highly toxic arsenate and arsenite during migration transformation. Herein, a three-dimensional polyethylenimine-aminated leather collagen fiber (CF-PEI) decorated with MgZnFe (MZF) metal oxides, i.e., CF-PEI@MZF monolith, was reported for the ultradeep p-ASA removal. The synergetic functions of hydrogen bonding and electrostatic interaction from the CF-PEI and coordinative interaction from the MZF on the monolith allow an ultrarapid kinetic that could achieve ca. 80% of the adsorption equilibrium within 20 min and a benchmarked exothermic Langmuir adsorption capacity as high as 588.24 mg g–1 for the p-ASA. It also performed an unparalleled feasibility in the continuous treatment to reduce the concentration of p-ASA to below 0.05 mg L–1 for real applications. We also highlight the monolith structure with great features of easy separation and recycling use for real industrial applications. All these demonstrate the merits of our CF-PEI@MZF monolith in addressing environmental engineering challenges.
Due to their good biodegradability and biocompatibility, magnesium alloys are widely favored as the potential candidate for the biodegradable cardiovascular stent. However, the rapid degradation and the limited biocompatibility in vivo remain the main bottlenecks that inhibit their clinical applications. The construction of the chemical conversion coating on the magnesium alloy surface represents one of the effective strategies to control the degradation rate and enhance the biocompatibility. In the present study, the different chemical conversion layers were prepared on the magnesium alloy surface by chemical conversion treatment, including sodium hydroxide (NaOH), hydrofluoric acid (HF), phosphoric acid (H3PO4) and phytic acid (C6H18O24P6) treatment, and the corrosion behaviors and biocompatibility of the chemical conversion layers were comparatively investigated in detail. The results showed that the different chemical treatments can produce the different conversion layers on the magnesium alloy surfaces with a variety of physicochemical characteristics, corrosion resistance and biocompatibility, and all treatments can enhance the corrosion resistance to varying degrees. The hydrophilicity and corrosion resistance of the sodium hydroxide-treated magnesium alloy were the best among all the materials. Although the hydrofluoric acid-treated magnesium alloy had produced a hydrophobic coating, the corrosion resistance still needed to be improved. Magnesium alloys treated by sodium hydroxide showed a selective promotion of albumin adsorption, while the other samples simultaneously promoted albumin and fibrinogen adsorption. For the blood compatibility, the hemolysis rates of all of the treated materials were reduced to below 5%. The samples treated by phytic acid had the smallest hemolysis rate, and the NaOH-treated magnesium alloy had the least amount of platelet adhesion and activation. An appropriate microenvironment for cell growth could be achieved by the chemical conversion treatment, according to the results of the endothelial cell adhesion and proliferation, and the NaOH-treated surface showed the best endothelial cell growth behaviors among all of the samples. In summary, the corrosion resistance and biocompatibility of the magnesium alloy were significantly improved by the sodium hydroxide treatment, and thus this treatment can be used as a pretreatment for the surface modification of the magnesium alloy in order to further enhance the biocompatibility when used as the cardiovascular implants.
Taking Shanxi fat coal, Shanxi 4# coke coal and Shenmu low rank pulverized coal as raw materials, three different concentrations of NaOH modified corn stalk were used as binder. The effect of changing NaOH concentrations and coal particle size used in moulding briquette and formed coke on its SEM micrographs, combustion property and FTIR absorption strength were investigated. The micro-properties of corn stalk before and after modification was also discussed. Results showed that the moisture content and ash yield of modified corn stalk increased obviously and the volatile yield showed opposite trend. 2.0% NaOH modified corn stalk showed more voids or porosity which could wrap a large number of coal particles to form strong strength briquette. Addition of modified corn stalk could reduces the briquette burning time and increased burning rate with strong flame and good ignition. From SEM micrograph, briquette had rough surface, and different sizes coal particles and fiber were bound together firmly. Formed coke showed light gray metallic luster, light mass, obvious circular holes and small gaps among particles.The melting colloid and binder could better infiltrate and encapsulate coal particles to form a dense and impermeable entity, which blocked the channels of organic group decomposition during pyrolysis process. Thus, it is forming many holes of different sizes on the surface and inside formed coke. The infrared spectrum of formed coke was simplier than briquette, and the absorption peak number was less and absorption strength was weaker also.
Dual-atom catalysts present a promising catalytic platform for improving activity and selectivity simultaneously. In their Research Article (e202401168), Xiaohao Liu et al. develop a universal "photo-induced neighbour-deposition" strategy to precisely construct In2O3-supported diatomic Ir-Pd sites. The strong synergism on the Angstrom scale accelerates *H spillover and electron transfer from Pd to Ir. This as-prepared catalyst exhibits a record-breaking performance for CO2 hydrogenation to methanol.
Abstract Selective activation of prodrugs is an important approach to reduce the side effects of disease treatment. We report a prodrug design concept for metal complexes, termed “metal‐carrying prochelator”, which can co‐carry a metal ion and chelator within a single small‐molecule compound and remain inert until it undergoes a specifically triggered intramolecular chelation to synthesize a bioactive metal complex in situ for targeted therapy. As a proof‐of‐concept, we designed a H 2 O 2 ‐responsive small‐molecule prochelator, DPBD, based on the strong chelator diethyldithiocarbamate (DTC) and copper. DPBD can carry Cu 2+ (DPBD‐Cu) and respond to elevated H 2 O 2 levels in tumor cells by releasing DTC, which rapidly chelates Cu 2+ from DPBD‐Cu affording a DTC–copper complex with high cytotoxicity, realizing potent antitumor efficacy with low systemic toxicity. Thus, with its unique intramolecularly triggered activation mechanism, this concept based on a small‐molecule metal‐carrying prochelator can help in the prodrug design of metal complexes.
Cancer cells immersed in inherent oxidative stress are more vulnerable to exogenous oxidative damages than normal cells. Reactive oxygen species (ROS)-mediated oxidation therapy preferentially aggravating tumor oxidative stress to disrupt redox homeostasis, has emerged as an effective and specific anticancer treatment. Herein, following an ingenious strategy of "broaden sources and reduce expenditure", we designed a versatile tumor-specific oxidative stress nanoamplifier enabling economized photodynamic therapy (PDT), to achieve synergistic oxidative stress explosion for superior oxidation therapy. Methods: Cinnamaldehyde (CA) as a therapeutic ROS generator was first conjugated to hyaluronic acid (HA) through acid-labile hydrazone bond to synthesize tailored amphiphilic HA@CA conjugates, which could surprisingly self-assemble into uniform nanofibers in aqueous media. Photosensitizer protoporphyrin (PpIX) was efficiently encapsulated into HA@CA nanofibers and transformed HA@CA nanofibers to final spherical HA@CAP. Results: With beneficial pH-responsiveness and morphology transformation, improved bioavailability and selective tumor accumulation, HA@CAP combining ROS-based dual chemo/photodynamic treatment modalities could induce cytotoxic ROS generation in a two-pronged approach to amplify tumor oxidative stress, termed "broaden sources". Moreover, utilizing CA-induced H2O2 production and cascaded Fenton reaction in mitochondria to consume intracellular overloaded Fe(II), HA@CAP could skillfully block endogenic heme biosynthesis pathway on site to restrain undesired elimination of PpIX for economized PDT, termed "reduce expenditure". Both in vitro and in vivo results demonstrated the superior antitumor performance of HA@CAP. Conclusion: This study offered an inspiring strategy of "broaden sources and reduce expenditure" to specifically boost tumor oxidative stress for reinforced oxidation therapy.
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