Epoxy resins (EPs) require the addition of flame retardants to extend their application scope. High-efficiency flame retardants typically contain halogens, which can cause tremendous harm to humans and the environment. In this study, we investigated the syntheses of new phosphorus–nitrogen flame retardants (DIT) and flame-retardant EP. DIT is composed of 6-(2,5-dihydroxyphenyl) dibenzo[c,e][1,2] oxaphosphinine 6-oxide, 5-isocyanato-1-(isocyanatomethyl)−1,3,3-trimethylcyclohexane, and tris-(2-hydroxyethyl) isocyanurate. DIT chemical structure was analysed by Fourier-transform infrared spectroscopy. Several formulations of modified epoxy resins (DIT-EPs) were obtained by adding different quantities of DITs. We found that when the flame retardant content reached 25%, the limiting oxygen index of the DIT-EP was 29.0%. This finding expands the application range of EPs.
Cao Ruijie,Zhou Rongwei,Wang Chuancui,Shen Meizhu,Yu Jiangyue,Xu Hao,Guo Zhong
Acute lung injury (ALI) is characterized by uncontrolled inflammation and oxidative stress, driven largely by macrophage dysregulation. Despite their anti-inflammatory potential, flavonoids like quercetin (Qu) are limited by poor solubility and systemic toxicity. To address these challenges, this study developed a “bioactive co-assembly” nanomicelle platform (Qu@PSA-VES/diT-VES) based on polysialic acid (PSA) and a novel dimerized taurine-vitamin E succinate (diT-VES). Molecular docking simulations demonstrated that quercetin (Qu) exhibits an exceptionally high binding affinity for the VES hydrophobic core. Furthermore, the incorporation of diT-VES significantly enhanced the colloidal stability of the micelles through strengthened non-covalent interactions, effectively preventing disassembly during physiological circulation. Hydrophobic interactions and hydrogen bonding were identified as the primary driving forces for micellar stability. The carrier leverages PSA to specifically target the overexpressed Siglec-1 receptor on the surface of inflammatory macrophages, thereby mediating receptor-dependent endocytosis. Within the acidic and enzyme-enriched lysosomal environment, the micelles undergo pH/enzyme dual-responsive dissociation, facilitating the escape of the drug from the lysosomal barrier and its subsequent diffusion into the cytoplasm for pharmacological action. Additionally, the carrier components VES and taurine provide antioxidant and mitochondrial protection, respectively, synergizing with Qu to significantly induce the reprogramming of M1 macrophages toward the M2 phenotype in vitro. In a murine ALI model, the system demonstrated superior lung-targeting ability, significantly reducing the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in bronchoalveolar lavage fluid and alleviating pulmonary edema and neutrophil infiltration. Experimental results indicated that under a lethal ALI challenge, the 72-h survival rate of mice in the treatment group was significantly increased from 16.7% to 83.3%, while maintaining excellent in vivo biocompatibility. This integrated "targeting-stabilization-synergy" nanoplatform provides a promising translational strategy for the treatment of macrophage-driven inflammatory disorders.
Tong Chen,Wanjing Cui,Ziwei Bi,Yafei Guo,Guoliang Zhu,Xiuyun Pan,Zhiqiang Cui,Zhen Yang,Tianlong Deng
The analysis of iodine content in kelp is mainly focused on determining total iodine content, which lacks a rapid and sensitive analytical method for iodine species corresponding to iodate, iodide, monoiodotyrosine (MIT), and diiodo-tyrosine (DIT). Based on exploring the pretreatment methods of enzymatic hydrolysis of kelp, a rapid determination method of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for different iodine species existed in kelp samples was established. The pretreatment method is trypsin hydrolysis of kelp samples treated at 50°C for 10 hours, then the extraction solution was obtained by centrifugation, and filtration was proved for the first time. A high-efficiency separation anion-exchange column (Dionex IonPac AS-14) for iodate, iodide, MIT, and DIT with 0.1 mol·L−1(NH4)2CO3 solution at pH = 9 as a mobile phase, a flow rate of 0.8 mL·min−1 for the first 1500 s, and 1.2 mL·min−1 for the last 1800 s was confirmed. The linear ranges of the standard calibrations on four iodine species are 1.0–150 μg·L−1, and the detection limits are 1.62, 1.02, 1.59, and 2.55 μg·L−1, respectively, while the RSD values of four iodine species are all less than 2%. Under the optimized conditions, the proposed method was successfully applied for the speciation analysis of iodine in kelp samples.
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