Degradation of Poly(ethylene terephthalate) Catalyzed by Nonmetallic Dibasic Ionic Liquids under UV Radiation.

Nonmetallic ionic liquids (ILs) exhibit unique advantages in catalyzing poly (ethylene terephthalate) (PET) glycolysis, but usually require longer reaction times. We found that exposure to UV radiation can accelerate the glycolysis reaction and significantly reduce the reaction time. In this work, we synthesized five nonmetallic dibasic ILs, and their glycolysis catalytic activity was investigated. 1,8-diazabicyclo [5,4,0] undec-7-ene imidazole ([HDBU]Im) exhibited better catalytic performance. Meanwhile, UV radiation is used as a reinforcement method to improve the PET glycolysis efficiency. Under optimal conditions (5 g PET, 20 g ethylene glycol (EG), 0.25 g [HDBU]Im, 10,000 µW·cm-2 UV radiation reacted for 90 min at 185 °C), the PET conversion and BHET yield were 100% and 88.9%, respectively. Based on the UV-visible spectrum, it was found that UV radiation can activate the C=O in PET. Hence, the incorporation of UV radiation can considerably diminish the activation energy of the reaction, shortening the reaction time of PET degradation. Finally, a possible reaction mechanism of [HDBU]Im-catalyzed PET glycolysis under UV radiation was proposed.

The ionic liquids upon perchlorate to promote the C-C/C-O bonds cleavage in alkali lignin under photothermal synergism.

Transforming lignin into aromatic monomers is critically attractive to develop green and sustainable energy supplies. However, the usage of the additional catalysts like metal or base/acid is commonly limited by the caused repolymerized and environmental issues. The key step is to mediate electron transfer in lignin to trigger lignin C-C/C-O bonds cleavage without the catalysts mentioned above. Here, we report that the ionic liquids [BMim][ClO4] was found to trigger lignin electron transfer to cleave the C-C/C-O bonds for aromatic monomers without any additional catalyst. The proton transfer from [BMim]+ to [ClO4]- could polarize the anion and decrease its structure stability, upon which the active hydroxyl radical generated and induced lignin C-C/C-O bonds fragmentation via free radical-mediated routes with the assistance of photothermal synergism. About 4.4 wt% yields of aromatic monomers, mainly composed of vanillin and acetosyringone, are afforded in [BMim][ClO4] under UV-light irradiation in the air at 80 °C. This work opens the way to produce value-added aromatic monomers from lignin using an eco-friendly, energy-efficient, and simple route that may contribute to the sustainable utilization of renewable natural resources.

Progress in the catalytic glycolysis of polyethylene terephthalate.

This paper briefly reviews the development history of polyethylene terephthalate (PET) and the recycling of PET. As one of the most promising way to degrade PET into oligomers and monomers that can be used for the production of high-quality PET, catalytic glycolysis is highlighted in this review. The developments on metal salt, metal oxide and ionic solvent catalysts for glycolysis of PET are systematically summarized, besides, the proposed catalytic mechanisms of ionic liquids (ILs) and deep eutectic solvents (DESs) are presented. The metallic catalysts show high catalytic performance but causing serious environmental pollution and high waste treatment costs, thereby it is proposed that metal-free catalysts, especially ILs and DESs can be the "greener" alternatives to address the PET waste problem. Additionally, the studies related to the glycolysis kinetics are discussed in this review, showing the results that PET glycolysis process consists of heterogeneous and homogeneous depolymerization, and different models should be used to investigate different depolymerization stages in order to obtain a more realistic picture.

Ion-Exchange Resins for Efficient Removal of Colorants in Bis(hydroxyethyl) Terephthalate.

Bis(hydroxyethyl) terephthalate (BHET) obtained from waste poly(ethylene terephthalate) (PET) glycolysis often have undesirable colors, leading to an increased cost in the decoloration of the product and limiting the industrialization of chemical recycling. In this work, eight types of ion-exchange resins were used for BHET decoloration, and resin D201 showed an outstanding performance not only in the decoloration efficiency but also in the retention rate of the product. Under the optimal conditions, the removal rate of the colorant and the retention efficiency of BHET were over 99% and 95%, respectively. D201 showed outstanding reusability with five successive cycles, and the decolored BHET and its r-PET showed good chromaticity. Furthermore, the investigations of adsorption isotherms, kinetics, and thermodynamics have been conducted, which indicated that the decoloration process was a natural endothermic reaction. Adsorption interactions between the colorant and resin were extensively examined by various characterizations, revealing that electrostatic force, π-π interactions, and hydrogen bonding were the dominant adsorption mechanisms.

Adsorption Thermodynamics and Kinetics of Resin for Metal Impurities in Bis(2-hydroxyethyl) Terephthalate.

Adsorption of heavy metals from degraded of Polyethylene terephthalate (PET) products by strong cation exchange resin AmberliteIR-120 under optimized conditions toward the selectivity removal of metals are in the following order: Al3+ > Zn2+ > Mg2+ > Fe2+ > Ni2+. Therefore, kinetic and adsorption isotherm models were applied for fitting experimental data. Comparatively, adsorption isotherm study revealed that Langmuir isotherm model better fits adsorption on surface of resin over than the Freundlich model. In summary, AmberliteIR-120 strong acid cation exchange resin can be used as an efficient adsorbent for heavy metals removal from depolymerized products bis(2-hydroxyethyl) terephthalate.

Weak Bonds Joint Effects Catalyze the Cleavage of Strong C-C Bond of Lignin-Inspired Compounds and Lignin in Air by Ionic Liquids.

Oxidation of lignin to value-added aromatics through selective C-C bond cleavage via metal-free and mild strategies is promising but challenging. It was discovered that the cations of ionic liquids (ILs) could effectively catalyze this kind of strong bond cleavage by forming multiple weak hydrogen bonds, enabling the reaction conducted in air at temperature lower than 373 K without metal-containing catalysts. The cation [CPMim]+ (1-propylronitrile-3-methylimidazolium) afforded the highest efficiency in C-C bond cleavage, in which high yields (>90 %) of oxidative products were achieved. [CPMim]+ could form three ipsilateral hydrogen bonds with the oxygen atom of C=O and ether bonds at both sides of the C-C bond. The weak bonds joint effects could promote adjacent C-H bond cleave to form free radicals and thereby catalyze the fragmentation of the strong C-C. This work opens up an eco-friendly and energy-efficient route for direct valorization of lignin by enhancing IL properties via tuning the cation.

Expression of Caveolin-1 Is Associated With Thyroid Function in Patients With Human Papillary Thyroid Carcinoma.

OBJECTIVE: The aim of this study was to evaluate the levels of caveolin-1 in thyroid follicular epithelial cells of papillary thyroid cancer, follicular thyroid cancer, and nonmalignant thyroid nodule benign follicular adenoma, as well as to explore the relationship between the levels of caveolin-1 and thyroid function. METHODS: Thirty cases of papillary thyroid cancer, 10 cases of follicular thyroid cancer, 32 cases of nonmalignant thyroid nodule benign follicular adenoma, and 30 controls were enrolled in this study. Caveolin-1 expression in tissue specimens obtained from these cases was evaluated by immunohistochemistry and Western blotting. RESULTS: Caveolin-1 expression in thyroid epithelial cells of patients with papillary thyroid cancer, particularly female patients, was significantly higher than that in patients with follicular thyroid cancer and nonmalignant thyroid nodule benign follicular adenoma (P < .005). Serum thyroid-stimulating hormone (TSH) levels in the caveolin-1-positive expression group were lower than that in the caveolin-1-negative expression group, and the lowest expression of caveolin-1 was detected in tissues of patients with Graves' disease. The serum TSH level was associated with caveolin-1 expression in thyroid epithelial cells. CONCLUSION: Caveolin-1 may participate in regulating thyroid function and is a potential biomarker of follicular thyroid cancer.

VWF, CXCL8 and IL6 might be potential druggable genes for acute coronary syndrome (ACS).

OBJECTIVE: Acute coronary syndrome (ACS) is currently a leading cause of morbidity and mortality worldwide. This study aimed to screen critical genes and miRNAs involved in ACS. MATERIALS AND METHODS: Microarray data (access number GSE19339) was downloaded from Gene Expression Omnibus (GEO) database. After data preprocessing, we screened the differentially expressed genes (DEGs) using limma package and subsequently performed enrichment analysis using DAVID tool. The protein-protein interaction (PPI) network and transcription factor (TF)-miRNA-target gene regulatory network were visualized using Cytoscape software. Finally, the drug-gene interactions were predicted using DGIdb database. RESULTS: A total of 425 DEGs were identified in ACS samples compared with healthy control samples. Functional enrichment analysis showed that DEGs were mainly involved in angiogenesis, inflammatory response and PI3K-Akt signaling pathway. IL6 and VEGFA were key nodes in PPI network. In addition, hsa-miR-29, hsa-miR-1, NFIC, NFKB1 and RELA were identified as key factors in TF-miRNA-target gene network. Finally, the prediction results revealed that VWF, CXCL8 and IL6 had higher degree than other genes. CONCLUSION: IL6 and VEGFA might play major roles in ACS progression. Two miRNAs (hsa-miR-29 and hsa-miR-1) and three TFs (NFIC, NFKB1 and RELA) were critical genes involved in pathological process of ACS. VWF, CXCL8 and IL6 might be potential druggable genes for ACS therapy.

Highly Efficient Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid with Heteropoly Acids and Ionic Liquids.

2,5-Furandicarboxylic acid (FDCA) is regarded as an important bioderived substitute for petrochemically derived terephthalic acid (PTA), which is widely applied in the polymer industry. This work delineates the base-free oxidation of 5-hydroxymethylfurfural (HMF) to FDCA in an ionic liquid/heteropoly acid (IL-HPA) catalytic system. HPAs displayed high activity for selective oxidation; their active center (Mo/V) was activated by O2 and transformed from oxygen single and double bonds to epoxy groups, resulting in an FDCA yield of 89 % for HPMV6 (HPM=H3 PMo12 O40 ) in the presence of [Bmim]Cl (1-butyl-3-methylimidazolium chloride) under optimized reaction conditions. The high solubility of imidazole ILs for FDCA improved the affinity of HMF and the active centers of the catalyst and protected the furan ring from oxidative cleavage. Furthermore, multiple hydrogen bonds simultaneously formed between the electronegative anions and hydroxy protons of HMF, as well as the hydrogen atoms of the imidazole rings and hydroxy groups, promoting the transformation to aldehyde groups. Various starting materials were studied, and a moderate FDCA yield was obtained from glucose. This work provides an interesting IL-HPA catalytic system for the base-free synthesis of FDCA from accessible monosaccharides and illustrates the great potential of FDCA production from renewable carbohydrates.

Schisandrin B displays a protective role against primary pulmonary hypertension by targeting transforming growth factor ß1.

Pulmonary arterial smooth muscle cells (PASMCs) in the medial layer of the vessel wall are involved in vessel homeostasis, but also for pathologic vascular remodeling in diverse diseases, such as pulmonary arterial hypertension (PAH). Pulmonary vascular remodeling in PAH results in vascular disorders, but its underlying molecular mechanisms are still not to be fully disclosed. In this study, we investigated the expression and function of the transforming growth factor (TGF)-ß1 in human PASMC cultured under the condition of hypoxia and elucidated the effect of schisandra chinensis and its active ingredients on proliferation, migration, and apoptosis in human PASMCs. We demonstrated that schisandrin B (Sch.B) alleviated the severity of PAH in PASMCs cultured under the condition of hypoxia. Significant upregulation of TGF-ß1 was observed in hypoxia-induced human PASMCs. Interestingly, administration of Sch.B substantially attenuated TGF-ß1 level in these PASMCs. In order to elucidate Sch.B function, the hypoxia-induced human PASMC was stimulated with Sch.B or cotreatment with TGF-ß1 in vitro. In agreement with its TGF-ß1-reducing effect, Sch B relieved human PASMCs migration and promoted the apoptosis of human PASMCs, by activation of TGF-ß1 downstream signal pathways in PASMCs. In contrast, co-treatment with TGF-ß1 promoted human PASMC proliferation and migration and inhibited the apoptosis of human PASMC, which can attenuate the protective role of Sch.B in human PASMC. Taken collectively, these findings suggest that the vascular relaxation evoked by Sch.B was mediated by direct effect on vascular smooth muscle cell via TGF-ß1 downstream signal pathways.

Resveratrol Ameliorates Cardiac Hypertrophy by Down-regulation of miR-155 Through Activation of Breast Cancer Type 1 Susceptibility Protein.

BACKGROUND: The polyphenol resveratrol (Rev) has been reported to exhibit cardioprotective effects, such as inhibition of TAC (transverse aortic constriction) or isoprenaline (ISO)-induced hypertrophy. MicroRNA-155 (miR-155) was found to be decreased in hypertrophic myocardium, which could be further reduced by pretreatment of Rev. The study was designed to investigate the molecular effects of miR-155 on cardiac hypertrophy, focusing on the role of breast cancer type 1 susceptibility protein (BRCA1). METHODS AND RESULTS: We demonstrated that Rev alleviated severity of hypertrophic myocardium in a mice model of cardiac hypertrophy by TAC treatment. Down-regulation of miR-155 was observed in pressure overload- or ISO-induced hypertrophic cardiomyoctyes. Interestingly, administration of Rev substantially attenuated miR-155 level in cardiomyocytes. In agreement with its miR-155 reducing effect, Rev relieved cardiac hypertrophy and restored cardiac function by activation of BRCA1 in cardiomyoctyes. Our results further revealed that forkhead box O3a (FoxO3a) was a miR-155 target in the heart. And miR-155 directly repressed FoxO3a, whose expression was mitigated in miR-155 agomir and mimic treatment in vivo and in vitro. CONCLUSIONS: We conclude that BRCA1 inactivation can increase expression of miR-155, contributing to cardiac hypertrophy. And Rev produces their beneficial effects partially by down-regulating miR-155 expression, which might be a novel strategy for treatment of cardiac hypertrophy.