Polylactide (PLA) was plasticized by polyethylene glycols (PEGs) with five different molecular weights (M w = 200-20,000 g/mol). The effects of content and molecular weight of PEG on the crystallization and impact properties of PLA were studied by wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and V-notched impact tests, respectively. The results revealed that PEG-10,000 could significantly improve the crystallization capacity and impact toughness of PLA. When the PEG-10,000 content ranged from 0 to 20 wt%, the increases in both V-notched Izod and Charpy impact strengths of PLA/PEG-10,000 blends were 206.10% and 137.25%, respectively. Meanwhile, the crystallinity of PLA/PEG-10,000 blends increased from 3.95% to 43.42%. For 10 wt% PEG content, the crystallization and impact properties of PLA/PEG blends mainly depended upon PEG molecular weight. With increasing the M w of PEG, the crystallinity and impact strength of PLA/PEG blends first decreased and then increased. The introduction of PEG reduced the intermolecular force and enhanced the mobility of PLA chains, thus improving the crystallization capacity and flexibility of PLA.

The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System Xc−), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System Xc−/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System Xc−/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System Xc−/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.

Understanding the rheological behavior of plasticized polylactide (PLA) contributed to the optimization of processing conditions and revealed the microstructure–property relationships. In this study, the morphological, thermal, steady and dynamic rheological properties of the PLA/poly(ethylene glycol) (PEG) blends were investigated by scanning electron microscope, differential scanning calorimeter, and capillary and dynamic rheometers, respectively. The results illuminated that the melt shear flow basically fitted the power law, whereas the temperature dependence of the apparent shear viscosity (ηa) or complex viscosity (η*) followed the Arrhenius equation. Both the neat PLA and PLA/PEG blends exhibited shear‐thinning behavior. Because the incorporation of PEG reduced the intermolecular forces and improved the mobility of the PLA chains, the ηa, η*, and storage and loss moduli of the PLA/PEG blends decreased. The PEG content (WPEG) ranged from 0 to 10 wt %, both ηa and η* decreased significantly. However, the decrements of ηa and η* became unremarkable when WPEG exceeded 10 wt %. The reason was attributed to the occurrence of phase separation, which resulted in the decrease in the plasticization and lubrication efficiencies. This study demonstrated that the addition of the right amount of PEG obviously improved the flow properties of PLA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42919.

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Alzheimer’s disease (AD), the most common type of senile dementia, includes the complex pathogenesis of abnormal deposition of amyloid beta-protein (Aβ), phosphorylated tau (p-tau) and neuroimmune inflammatory. The neurodegenerative process of AD triggers microglial activation, and the overactivation of microglia produces a large number of neuroimmune inflammatory factors. Microglia dysfunction can lead to disturbances in iron metabolism and enhance iron-induced neuronal degeneration in AD, while elevated iron levels in brain areas affect microglia phenotype and function. In this manuscript, we firstly discuss the role of microglia in AD and then introduce the role of microglia in the immune-inflammatory pathology of AD. Their role in AD iron homeostasis is emphasized. Recent studies on microglia and ferroptosis in AD are also reviewed. It will help readers better understand the role of microglia in iron metabolism in AD, and provides a basis for better regulation of iron metabolism disorders in AD and the discovery of new potential therapeutic targets for AD.

The intumescent flame retardant (IFR) filled polypropylene (PP) composites were prepared using a twin-screw extruder. The tensile and impact fracture behavior of the composites were measured at room temperature. It was found that the Young's modulus increased roughly, while the tensile strength decreased slightly with increasing the IFR weight fraction; the toughening effect of the filler on the PP resin was significant. Both the V-notched Izod impact strength and the V-notched Charpy impact strength of the PP/IFR composites showed a nonlinear increase with increasing the filler weight fraction (ϕ f ) as ϕ f was less than 20%, then it decreased. The limited oxygen index of the composites increases nonlinearly with increasing ϕ f . The relationship between them obeyed a quadratic equation. The impact fracture surface was observed by means of a scanning electronic microscope to understand the toughening mechanisms for the composite systems.

The mechanical properties of mesoporous silica (MCM‐41) filled poly(l‐lactic acid) (PLA4032D) composites and PLA4032D/poly(ethylene glycol) (PEG) composites were investigated. It was found that the Young's modulus increased while tensile strength decreased with increasing the filler content; the V‐notched impact fracture strengths of both Izod and Charpy for the PLA4032D/PEG/MCM‐41 composites increased while they decreased slightly for the PLA4032D/MCM‐41 composites, the unnotched Charpy impact strength of both the two composites decreased with increasing the filler loading; the flexural modulus increased slightly while the flexural strength decreased slightly with increasing the filler content. The toughening mechanisms of the composites were discussed by means of observing the impact fracture surface with a scanning electronic microscope, and the synergistic effect between the PEG and MCM‐41 should be one of the major toughening mechanisms. POLYM. COMPOS., 38:1118–1126, 2017. © 2015 Society of Plastics Engineers

Malignant tumor is a major killer that seriously endangers human health. At present, the methods of treating tumors include surgical resection, chemotherapy, radiotherapy and immunotherapy. However, the survival rate of patients is still very low due to the complicated mechanism of tumor occurrence and development and high recurrence rate. Individualized treatment will be the main direction of tumor treatment in the future. Because only by understanding the molecular mechanism of tumor development and differentially expressed genes can we carry out accurate treatment and improve the therapeutic effect. MicroRNA (miRNA) is a kind of small non coding RNA, which regulates gene expression at mRNA level and plays a key role in tumor regulation. Ferroptosis is a kind of programmed death caused by iron dependent lipid peroxidation, which is different from apoptosis, necrosis and other cell death modes. Now it has been found that ferroptosis plays an important role in the occurrence and development of tumors and drug resistance. More and more studies have found that miRNAs can regulate tumor development and drug resistance through ferroptosis. Therefore, in this review, the mechanism of ferroptosis is briefly outlined, and the relationship between miRNAs and ferroptosis in tumors is reviewed.