Liberation of plastic nanoparticles and organic compounds from three common plastics in water during weathering under UV radiation-free conditions.

A 620-day batch experiment was conducted to examine the generation of nano-sized plastic particles and migration of organic compounds derived from plastic additives and impurities during the weathering of three common plastic types in water with and without reactive oxygen species. The results show that the amount of nanoplastics plus organic compounds liberated from the tested plastic films, as indicated by total organic carbon, was in the following decreasing order: PET >PP > ABS. Hydroxyl radical generated from Fenton-like reaction significantly enhanced the generation of nanoplastics and release of organic compounds from the weathered plastic films via oxidative degradation. Over 30 organic compounds including potentially toxic organic pollutants originated from plastic additives and impurities were detected. There was a marked difference in the plastic nanoparticle size distribution between the deionized water and the water containing reactive oxygen species. The strong oxidizing capacity of hydroxyl radical resulted in rapider disintegration of the coarser nanoparticles (>500 nm) into the finer nanoparticles (<500 nm) and allowed complete decomposition of the nanoplastics with a size <50 nm or even <100 nm. Elevated level of Ca was detected on the surfaces of the ABS and PP nanoparticles. PP- and PET-derived nanoplastics contained heavy metal(loid)s while no heavy metal(loid)s was detected for the ABS nanoparticles. PET nanoparticles had a stronger capacity to bind S- and N-containing organic ligands compared to the other two plastic nanoparticles. The nanoplastics generated from the weathering were irregular in shape, which means that they had larger specific area compared to spherical engineered nanoplastics.

Generation of micro(nano)plastics and migration of plastic additives from Poly(vinyl chloride) in water under radiation-free ambient conditions.

A batch experiment was conducted to observe the liberation of micro- and nano-sized plastic particles and plastic additive-originated organic compounds from poly(vinyl chloride) under radiation-free ambient conditions. The weathering of PVC films in deionized water resulted in isolated pockets of surface erosion. Additional ●OH from Fenton reaction enhanced PVC degradation and caused cavity erosion. The detachment of plastic fragments from the PVC film surfaces was driven by autocatalyzed oxidative degradation. Over 90% of micro-sized plastic particles were <60 µm in length. The detached plastic fragments underwent intensified weathering, which involved strong dehydrochlorination and oxidative degradation. Further fragmentation of micro-sized particles into nano-sized particles was driven by oxidative degradation with complete dehydrochlorination being achieved following formation of nanoplastics. 20 organic compounds released from the PVC films into the solutions were identified. And some of them can be clearly linked to common plastic additives. In the presence of additional ●OH, the coarser nanoplastic particles (>500 nm) tended to be rapidly disintegrated into finer plastic particles (<500 nm), while the finest fraction of nanoplastics (<100 nm) could be completely decomposed and disappeared from the filtrates. The micro(nano)plastics generated from the PVC weathering were highly irregular in shape.

The effect of surgery plus intensity-modulated radiotherapy on treatment in laryngeal cancer: A clinical retrospective study.

PURPOSE: As a common head and neck tumor, laryngeal cancer has attracted heightened attention for its treatment and prognosis. Surgery and radiotherapy were mainly therapeutic approaches in laryngeal cancer, and intensity-modulated radiotherapy (IMRT) was a precision treatment way in radiotherapy. However, the therapeutic effect of surgery plus IMRT in laryngeal cancer was rarely reported. This study aims to determine the effect of IMRT on the treatment of patients with laryngeal cancer. METHODS: A total of 125 patients with laryngeal cancer were collected and retrospectively analyzed based on their clinical data and follow-up results. These patients had a clear treatment plan for surgery and intensity-modulated radiotherapy. RESULTS: Smoking, lymph node metastasis, TNM staging and therapeutic approaches could affect the survival of patients with laryngeal cancer. It was shown that the laryngeal function retention rate in the simple IMRT group was significantly higher than the simple surgery group and surgery plus IMRT group. The 5-year survival rate of surgery plus IMRT, simple surgery and simple IMRT were 82.86%, 53.85% and 43.33%, respectively. The locoregional recurrences rate of surgery plus IMRT, simple surgery and simple IMRT were 14.29%, 34.62% and 43.33%. CONCLUSION: Surgery plus IMRT was a feasible and efficacious treatment technique for patients with laryngeal cancer, which effectively prolong the survival time of patients.