Effects of UV light on physicochemical changes in thermoplastic polyurethanes: Mechanism and disinfection byproduct formation.

The presence of microplastics (MPs) products and particles in the environment can significantly impact the human body. Most MPs that enter the environment also enter the water cycle. During sunlight light irradiation (especially ultraviolet (UV) part) or UV disinfection, many of these MPs, particularly those rich in surface functional groups like thermoplastic polyurethanes (TPU), undergo physicochemical changes that can affect the formation of disinfection byproducts (DBPs). This study investigates the physicochemical changes of TPU in water after exposure to UV irradiation and incubation in the dark, as well as the formation of DBPs after chlorination. The results show that TPU undergo chain breakage, oxidation, and cross-linking when exposed to UV irradiation in an aqueous system. This leads to fragmentation into smaller particles, which facilitates the synthesis of DBPs. Subsequent research has demonstrated that the TPU leaching solution produces a significantly higher DBP content than the chlorination of TPU MPs, particularly at high concentrations of CHCl3. Therefore, it is important to give greater consideration to the soluble DBP precursors released by TPU.

Photoelectrocatalytic modification of nanofiltration membranes with SrF2/Ti3C2Tx to simultaneously enhance heavy metal ions rejection and permeability.

Heavy metal pollution can significantly harm water systems and human health. Combining photoelectrocatalytic (PEC) and nanofiltration (NF) membrane separation technologies can effectively remove heavy metal ions from wastewater. In this study, a water bath method was used to form SrF2/Ti3C2Tx (ST) nanoparticles on the surface of polyvinylidene fluoride (PVDF) membranes and an additional polyamide (PA) functional layer was formed at the interface by crosslinking. ST@PA composite NF membranes (STPP) with good photocatalytic performance were obtained. The separation and catalytic properties of the STPP membranes were controlled by the ST content, which modifies the surface structure and properties of the membranes. The membrane with optimal ST crosslinking exhibited a water contact angle of 50.8°, pure water flux of 24.6 L·m-2·h-1·bar-1, and rejection rates of Mn2+, Ni2+, Cu2+, and Zn2+ of 98.8%, 95.3%, 95.7%, and 97.3%, respectively, under PEC-assisted separation with visible light illumination from a Xe lamp (300 W) and an applied voltage (2 V). The STPP membranes showed improved rejection rates of heavy metal ions under PEC-assisted operation. The mechanism for the improved membrane performance under PEC conditions was preliminarily clarified considering the relationship between the photocatalytic and filtration properties of STPP membranes along with the influence of light irradiation and an external voltage on the heavy metal ions. The generation of electrons, holes, superoxide radicals, and hydroxyl radicals during membrane operation enhances the rejection rates of heavy metal ions. Based on these results, STPP membranes are considered a promising technology for industrial applications in heavy metal removal.

Two new cytotoxic cardenolides from the latex of Antiaris toxicaria.

Two new cardenolides, toxicarioside F (1) and toxicarioside G (2), were isolated from the latex of Antiaris toxicaria (Pers.) Lesch (Moraceae). Their structures were elucidated on the basis of spectral data and chemical evidence. Compounds 1 and 2 showed significant cytotoxicity against K562, SGC-7901, SMMC-7721, and HeLa cell lines in vitro by the MTT method.

A new cytotoxic 19-nor-cardenolide from the latex of Antiaris toxicaria.

A new nor-cardenolide, named toxicarioside H (1), was isolated from the latex of Antiaris toxicaria (Pers.) Lesch (Moraceae). Its structure was elucidated on the basis of HRFAB-MS and spectroscopic techniques (IR, UV, 1D and 2D NMR). Compound 1 showed significant cytotoxicity against K562, SGC-7901, SMMC-7721, and HeLa cell lines in vitro by MTT method.

[Clinical application of various forms of free profunda femoral artery pedicled chimeric myocutaneous perforator flap in defect reconstruction after tongue carcinoma resection].

Objective: To investigate the clinical anatomy and application of free profunda femoral artery pedicled chimeric myocutaneous perforator flap in the defect reconstruction after radical resection of tongue carcinoma. Methods: Between April 2011 and January 2016, 44 cases of tongue carcinoma underwent radical resection, and tongue defects were reconstructed by free profunda femoral artery pedicled chimeric myocutaneous perforator flaps at the same stage. There were 40 males and 4 females, with a mean age of 46.3 years (range, 32-71 years). The pathologic type was squamous cell carcinoma, which involved the lingual margin in 24 cases, the ventral tongue in 17 cases, and the mouth floor in 3 cases. According to Union for International Cancer Control (UICC) TNM staging, 16 cases were rated as T 4N 0M 0, 11 cases as T 4N 1M 0, 9 cases as T 3N 1M 0, and 8 cases as T 3N 2M 0. The course of disease ranged from 1 to 22 months (mean, 8.6 months). The size of perforator flap ranged from 8.5 cm×4.0 cm to 12.0 cm×6.5 cm, and the size of muscle flap ranged from 4.0 cm×3.0 cm to 7.5 cm×5.0 cm. The adductor magnus myocutaneous flap with a pedicle of (8.3±0.5) cm was used in 11 cases, and the gracilis muscle myocutaneous flap with a pedicle of (8.1±0.8) cm was used in 33 cases. The donor sites were sutured directly. Results: All 44 perforator flaps survived uneventfully, and the donor site healed well. The patients were followed up for 12 to 40 months (mean, 23.8 months). The reconstructed tongue had good appearance and function in swallowing and language. No local recurrence was found. Only linear scar was left at the donor sites. Conclusion: The free profunda femoral artery pedicled chimeric myocutaneous perforator flap can be harvested in various forms, and is an ideal choice to reconstruct defect after radical resection of tongue carcinoma.

Self-assembly of polypyrrole/chitosan composite hydrogels.

Hydrogels based on the polypyrrole (PPy)/chitosan (CS) composite are self-assembled and characterized for their electrical and swelling properties. The static polymerization of pyrrole monomer in aqueous solution containing CS is accompanied with the formation of PPy/CS composite hydrogel. The feed order in the reaction process plays a key role in the formation of the hydrogels. The participation of one-dimensional PPy blocks in the formation of the hydrogel network avoids a possible migration of PPy from the hydrogel. The effect of pH and ionic strength on the physical properties of PPy/CS composite hydrogels are investigated in detail. The results indicate that the pH-sensitive PPy/CS composite hydrogels show good water absorbencies in distilled water and saline solution. This method may open a new opportunity for the fabrication of composite hydrogels associating the biomacromolecules and conducting polymers, and the improvement of the comprehensive performance of the resulting products.