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AIM: This study aims to investigate the histopathological and ultrastructural alterations in the lung tissues of rats induced by a single intratracheal administration of bleomycin, with the objective of establishing a reliable model for future applications. METHODS: Six to eight-week-old SD rats were randomly allocated into two groups: the control group and the model group (n=12). Pulmonary fibrosis was induced in the rat models by a single intratracheal instillation of bleomycin (3 mg/kg), while an equivalent volume of saline was administered to the control group. The rats were executed on the 42nd day. Twelve rats remained in the control group, while nine rats remained in the model group. Lung tissue imaging was conducted using CT scans. Lung function tests were performed to assess changes in forced vital capacity (FVC) and dynamic lung compliance (Cdyn). Lung stiffness was determined through Young's modulus testing using a rheometer. The pathological structure of lung tissues was examined using both HE and Masson staining methods. Additionally, transmission electron microscopy was employed to evaluate collagen deposition in lung tissues, alveolar type II epithelial cells, macrophages, and ultrastructural changes of the respiratory membrane. RESULTS: CT scans revealed honeycomb patterns in the lungs of model rats, along with partial bronchiectasis/bronchiectasis. In comparison to the control group, the model group exhibited significantly lower FVC and Cdyn values, while lung stiffness were increased. HE and Masson staining demonstrated that rats in the model group exhibited alveolar structure destruction, alveolar septum thickening, inflammatory cell infiltration, and collagen deposition in alveolar septum. Transmission electron microscopy revealed several abnormalities in the model group: increased collagen fibers in the alveolar septa, misalignment of micro-villi in alveolar type II epithelial cells, wrinkled nuclei with increased heterochromatin, swollen cytoplasmic mitochondria, fractured or haphazardly structured mitochondrion cristaes, and a significant decrease in their number (P<0.05). Furthermore, lamellar bodies were vacuolated and reduced in number (P<0.05), and dilated endoplasmic reticulums with degranulation were observed. There was an increase in alveolar macrophages and interstitial macrophages (P<0.01). The respiratory membrane displayed structural disruptions and an increase in thickness (P<0.01). CONCLUSION: Bleomycin induces decreased lung compliance, alveolar epithelial injury, alveolar septum thickening, collagen deposition, and an increase in interstitial macrophages, ultimately resulting in pulmonary fibrosis in rats. [ABSTRACT FROM AUTHOR]

As one of the important sources of environmental pollution, the sound management of chemicals has entered the international agenda beyond 2020. This article presents the latest trends of sound management of chemicals in the international community, including the negotiation progress on the framework of Strategic Approach to International Chemicals Management (SAICM) and the sound management of chemicals and waste beyond 2020, relevant resolutions adopted by the Fifth United Nations Environment Conference, and preparations for the Science-Policy Panel to contribute further to the sound management of chemicals and waste and to prevent pollution, elabo- rates on the content of the framework text of SAICM beyond 2020 and analyzes the new changes and requirements of the international situation. The sound management of chemicals has become an important chapter in global environmental governance, and China is facing new international situations and challenges. As a new requirement of the Communist Party of China (CPC) Central Committee for deepening the battle against pollution, new pollutants control is the primary task of environmental risk management of toxic and harmful chemicals, which is highly consistent with the international goal of sound management of chemicals. At present, it is necessary to gather joint efforts from both domestic and international sources, actively respond to international challenges, and embark on a new journey in the domestic new pollutants control. [ABSTRACT FROM AUTHOR]

The application of bamboo fibers (BFs) as a reinforcing filler in polylactic acid (PLA) is hindered by their poor compatibility owing to the intrinsic hydrophilia of BFs and the hydrophobicity of PLA. To solve this issue, cardanol (CD) and epoxidized cardanol glycidyl ether (ECGE) were used as compatibilizers to strengthen and toughen PLA/BF bio‐composites, to the best of our knowledge, preparing PLA/BF/CD and PLA/BF/ECGE bio‐composites. The impact strengths of the synthesized bio‐composites increased from 7.75 to 23.75 and 7.75 to 23.95 kJ/m2, respectively, compared with that of a PLA/BF composite without compatibilizer. The investigation of the mechanical properties, crystallization, fractured surface morphology, and solvent stress‐cracking resistance properties revealed that the toughening mechanism of the PLA/BF/CD bio‐composites are mainly based on the plasticization of CD, which results in high impact toughness but low tensile strength. Moreover, the modification with ECGE improves the impact and tensile strengths of the bio‐composite owing to the following factors: (1) the epoxy groups of ECGE generate strong interactions with the BF surface and PLA to form an enhanced interfacial structure; (2) when present at high concentrations, chain extension reaction between ECGE and PLA to increase the molecular chain entanglement of PLA; and (3) upon curing and crosslinking, ECGE forms an entangled network structure that toughens the matrix. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) is a widely used plastics in different industries. It is an intrinsically hard and brittle polymer and requires the use of plasticizers to improve the processability. Commonly used phthalate‐based plasticizers have serious toxicity issues and we present alternatives based on epoxidized soybean oil (ESO) and epoxidized cardanol esters (ECEs). ECEs are synthesized from cardanol and three fatty acids (oleic, ricinoleic, and myristic) using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) as a coupling agent. Their structure and purity are confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance. Moreover, plasticized PVC films are prepared using a solvent‐free method. The replacement of 10 phr of ESO with 5 phr of ECE improves the plasticizing power due to the co‐solvency effect. Mechanical properties and thermal stability of plasticized PVC films are correlated with the chain length and the number of epoxy groups in ECE. The best plasticizing effect is observed for epoxidized cardanol‐myristate (ECD‐MA). ECD‐MA as a shorter‐chain secondary plasticizer is more compatible with ESO and allows higher conformational mobility of PVC chains. PVC/30ESO/5ECD‐MA polymer exhibits an exceptionally high initial thermal decomposition temperature (314.4°C) while preserving moderate ductility and tensile strength (263.4% and 23.3 MPa). Overall, this study highlights the potential applicability of ECD‐MA in combination with ESO as a sustainable, bio‐based plasticizer and heat stabilizer for flexible PVC products. [ABSTRACT FROM AUTHOR]