Latest ArticlesA novel citric acid-modified chitosan gel (CSCA) was synthesized through a simple one-step process and was used to extract thorium ions from wastewater. The CSCA samples with varying chemical compositions were analyzed using SEM with mapping EDS, FT-IR, and static water contact angle measurements, and their adsorption behaviors were studied in detail. The results showed that the adsorption performance of CSCA improves with the increase of CA content in the sample. CSCA possesses an impressive capacity for thorium adsorption of 279.8 mg/g. Furthermore, it showed an ultra-fast adsorption rate and reached equilibrium within 30 min. In terms of recyclability, the CSCA still retained more than 86% of its initial adsorption capacity after 6 cycles of reuse. Density functional theory (DFT) analysis reveals that the good selectivity of this material towards thorium ions should be attributed to the high density of adsorption sites and strong interaction between carboxyl groups and thorium ions. This work could be beneficial in the design and synthesis of new polymer materials for extracting thorium.
Ferroelastic hybrid perovskite materials have been revealed the significance in the applications of switches, sensors, actuators, etc. However, it remains a challenge to design high-temperature ferroelastic to meet the requirements for the practical applications. Herein, we reported an one-dimensional organic-inorganic hybrid perovskites (OIHP) (3-methylpyrazolium)CdCl3 (3-MBCC), which possesses a mmmF2/m ferroelastic phase transition at 263 K. Moreover, utilizing crystal engineering, we replace –CH3 with –NH2 and –H, which increases the intermolecular force between organic cations and inorganic frameworks. The phase transition temperature of (3-aminopyrazolium)CdCl3 (3-ABCC), and (pyrazolium)CdCl3 (BCC) increased by 73 K and 10 K, respectively. Particularly, BCC undergoes an unconventional inverse temperature symmetry breaking (ISTB) ferroelastic phase transition around 273 K. Differently, it transforms from a high symmetry low-temperature paraelastic phase (point group 2/m) to a low symmetry high-temperature ferroelastic phase (point group 1) originating from the rare mechanism of displacement of organic cations phase transition. It means that crystal BCC retains in ferroelastic phase above 273 K until melting point (446 K). Furthermore, characteristic ferroelastic domain patterns on crystal BCC are confirmed with polarized optical microscopy. Our study enriches the molecular mechanism of ferroelastics in the family of organic-inorganic hybrids and opens up a new avenue for exploring high-temperature ferroic materials.
Nonradical oxidation has received wide attention in advanced oxidation processes for environmental remediation. Understanding the relationship between material characteristics and their ability to initiate nonradical oxidation processes is the key to better material design and performance. Herein, a novel titanium-based metal-organic framework MIL-125-Ti/H2O2 system was established to show a highly selective degradation efficacy toward tetracycline antibiotics. MIL-125-Ti with the abundance of TiO6 octahedra units was found to effectively activate H2O2 under dark conditions by forming an oxidative Ti-peroxo complex. The presence of the Ti-peroxo complex, confirmed by UV-visible spectrophotometer, fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy characterizations, showed superior degradation (> 95% removal rate) of oxytetracycline hydrochloride (OTC), doxycycline hydrochloride, chlortetracycline hydrochloride, and tetracycline. Density functional theory calculations were performed to assist the elucidation on the mechanism of H2O2 activation and antibiotics degradation. The MIL-125-Ti/H2O2 system was highly resistant to halogens and background organics, and could well maintain its original catalytic activity in actual water matrices. It retained the ability to degrade 75% of OTC within ten test cycles. This study provides new insight into the nonradical oxidation process initiated by the unique Ti-peroxo complex of Ti-based MOF.
Conversion of CO2 into high-value products using electrochemical CO2 reduction (ECR) technology is an effective way to alleviate global warming and reach carbon neutrality. The oxygen vacancies in heterogenous catalysis are generally considered as a powerful method to enhance the performance of ECR by promoting CO2 adsorption and activation. However, the extent of defects in oxygen vacancies-activity relation has rarely been studied. Herein, we prepared Cu–Cd bimetallic catalysts with adjustable oxygen defect degree by controlling the amount of cadmium addition. Fourier transform infrared spectroscopy characterization results reveal that the formation of oxygen vacancies is attributed to the asymmetric stretching of Cu–O by the addition of cadmium. Electrochemical results show that the oxygen defect degree can modulate the selectivity of ECR products. A low degree of oxygen defects (CuO) is generally associated with lower product Faraday efficiency (FEC2/FEC1 ≈ 114%), but overabundant oxygen vacancies (CuO2.625–CdO0.375) are not entirely favorable to improving ECR activity (FEC2/FEC1 ≈ 125%) and single selectivity, while an appropriate degree of oxygen vacancies (CuO2.75–CdO0.25) can facilitate the ECR process toward single product selective production (FEC2/FEC1 ≈ 296%). The theoretical calculation showed that the O vacancy formed on CuO and the interface between CdO and CuO were conducive to enhancing the formation of *COOH intermediate and promoting the generation of ethylene products. This study provides a new approach and insight into the selective production of single products for future industrial applications of ECR.
The interaction among type Ⅱ collagen (CII), human DR4 major histocompatibility complex type Ⅱ molecule (MHC Ⅱ) and T-cell receptor (TCR) is associated with the development of rheumatoid arthritis (RA). The activation of T cells can be reduced through exposure to modified CII(263–272) glycopeptide fragment via competitive inhibition with self-antigen. In this work, 30 peptides based on the sequence of CII(263–272) were prepared and evaluated for their binding to DR4 protein by surface plasmon resonance (SPR) assay. The effect on the secretion of pro-inflammatory factors by the spleen cells in collagen induced rheumatoid arthritis (CIA) mouse was also investigated. Two N-glycosylated CII peptides were identified to have strong binding to the human recombinant DR4 protein and weak proinflammatory effect. These glycopeptides could be developed as therapeutic saccharide vaccines for the treatment of rheumatoid arthritis (RA).
Due to its high operational voltage and energy density, P2-type Na0.67Ni0.3Mn0.7O2 has become a leading cathode material for sodium-ion batteries (SIBs), which is an ideal option for large-scale energy storage. However, the practical application of P2-type Na0.67Ni0.3Mn0.7O2 is limited by the capacity constraints and unwanted phase transitions, presenting significant challenges to the widespread application of SIBs. To address these challenges and optimize the electrochemical properties of the P2 phase cathode material, this study proposes a Cu and Zn co-doped strategy to improve the electrochemical performance. The incorporation of Cu/Zn can stabilize the P2-phase structure against P2-O2 phase transitions, thus enhancing its electrochemical properties. The as-obtained P2-type Na0.67[Ni0.3Mn0.58Cu0.09Zn0.03]O2 cathode material shows an impressive cycling stability, maintaining 80% capacity retention after 1000 cycles at 2 C. The cyclic voltammetry (CV) tests show that the Cu2+/Cu3+ redox reaction is also involved in charge compensation during the charge/discharge process.
Ultra-high nickel material is considered to be a promising cathode material. However, with the increase of nickel content, the interfacial side reactions between the cathode and electrolyte become increasingly serious. Herein, an atomically controllable ionic conductor Li3PO4 (LPO) coating is deposited on the LiNi0.90Co0.06Mn0.04O2 (NCM9064) based electrode by the atomic layer deposition method. The results shows that the LPO coating is uniformly and densely covered on the surface of secondary particles of NCM9064, helping to prevent the direct contact between the electrolyte and cathode during the charging-discharging process. In addition, the coating layer is electrochemically stable. As a result, the interfacial side reactions during the long cycle are effectively suppressed, and the solid electrolyte interphase layer at the interface is stabilized. The electrode with 20 layers of LPO deposition (ALD-LPO-20) exhibits an excellent capacity retention of 81% after 200 cycles in 2.8-4.3 V at 25 ℃, which is 18% higher than the unmodified material (ALD-LPO-0). Besides, the moderate LPO coating improves the rate capability and high temperature cycling performance of NCM9064. This study provides a method for the modification of ultra-high nickel cathode materials and corresponding electrodes.
The platinum-based chemotherapy is a routine strategy for the treatment of ovarian cancer, while it is prone to chemoresistance in clinical, which hinders the treatment. Therefore, it is urgently needed to elucidate the underlying mechanism of drug resistance and form the appropriate strategy. The sequencing results showed that cisplatin (DDP) resistant ovarian cancer overexpressed BTB and CNC homology 1 (BACH1), and up-regulated the “don't eat me” signal CD47. We identified that hemin, a BACH1 inhibitor, could effectively down-regulate BACH1 and simultaneously inhibit CD47. Moreover, hemin has a synergistic effect with DDP. We designed a pH-responsive nanoparticle (H/D@FA–CaP–NPs) in which folic acid (FA) ensured targeting of ovarian cancer cells, while hemin inhibited BACH1 as well as down-regulated CD47, achieving the promotion of apoptosis of tumor cells and inducing phagocytosis of tumors by macrophages. Moreover, hemin has a synergistic effect with DDP to promote apoptosis of tumor cells. Structurally, hemin and DDP was encapsulated within hydrophobic 1,2-distearoyl-sn-glycero-3-phospho-ethanolamine (DSPE) to form a tight core, and hydrophilic polyethylene glycol 2000 (PEG2000) and calcium phosphate (CaP) formed the outside shell, and FA was modified on the surface of nanoparticles. In terms of function, (a) FA enhanced the active targeting of nanoparticles to tumors; (b) NPs targeted mitochondria to induce reactive oxygen species (ROS) production; (c) hemin encapsulated in nanoparticles could specifically target BACH1, thereby down regulating CD47; (d) hemin had a synergistic effect with DDP, thus augmenting the chemotherapy. Altogether, mitochondria-targeted nanoparticles H/D@FA–CaP–NPs promoted tumor apoptosis and mobilized phagocytosis to treat tumor, providing a novel scheme for clinical treatment of cisplatin-resistant ovarian carcinoma.
A novel cationic Pt(Ⅱ) complex 2 with 2-(2,4-difluorophenyl)pyridine as the cyclometalating ligand and 1,10-phenanthroline as the auxiliary ligand has been synthesized and fully characterized. This complex exhibits much higher aggregation-induced phosphorescent emission activity than that of a non-fluorinated complex 1 in CH3CN/H2O. The complex 2 demonstrates efficient detection on picric acid (PA) in CH3CN/H2O, providing a high quenching constant (KSV = 2.3 × 104 L/mol) and a low limit of detection (LOD = 0.26 µmol/L). In addition, complex 2 shows high selectivity for detection of PA in real water samples. Density functional theory calculations and proton nuclear magnetic resonance spectra suggest that the detection mechanism is attributed to the photo-induced electron transfer.
Staphylococcal enterotoxin A (SEA) derived from Staphylococcus aureus, as a superantigen, shows potential for cancer immunotherapy, but systemic immunotoxicity restricts its clinical application. Targeted delivery of SEA to tumor site provides a promising option for reducing the systemic toxicity. Here, we constructed an iRGD peptide (H-[Cys-Arg-Gly-Asp-Lys-Gly-Pro-Asp-Cys]-NH2) modified nanoparticle (iDPP) to deliver plasmids encoding SEA for melanoma treatment. The iDPP/SEA nanocomplexes efficiently mediated SEA expression in B16-F10 cells in vivo and in vitro and induced the activation of lymphocytes and maturation of murine bone marrow-derived dendritic cells (BMDCs) in vitro. In the subcutaneous B16-F10 melanoma model, the iDPP/SEA nanocomplexes could effectively enhance immune response and T lymphocytes infiltration in tumor site after intravenous administration, thereby considerably decreased melanoma growth. Meanwhile, no obvious adverse effect was observed after intravenous administration of the iDPP/SEA nanocomplexes in vivo. Our findings demonstrated that gene therapy of SEA is a potential candidate for melanoma treatment.
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