Development, Evaluation, and Application of Machine Learning Models for Accurate Prediction of Root Uptake of Per- and Polyfluoroalkyl Substances.

Machine learning (ML) models were developed for understanding the root uptake of per- and polyfluoroalkyl substances (PFASs) under complex PFAS-crop-soil interactions. Three hundred root concentration factor (RCF) data points and 26 features associated with PFAS structures, crop properties, soil properties, and cultivation conditions were used for the model development. The optimal ML model, obtained by stratified sampling, Bayesian optimization, and 5-fold cross-validation, was explained by permutation feature importance, individual conditional expectation plot, and 3D interaction plot. The results showed that soil organic carbon contents, pH, chemical logP, soil PFAS concentration, root protein contents, and exposure time greatly affected the root uptake of PFASs with 0.43, 0.25, 0.10, 0.05, 0.05, and 0.05 of relative importance, respectively. Furthermore, these factors presented the key threshold ranges in favor of the PFAS uptake. Carbon-chain length was identified as the critical molecular structure affecting root uptake of PFASs with 0.12 of relative importance, based on the extended connectivity fingerprints. A user-friendly model was established with symbolic regression for accurately predicting RCF values of the PFASs (including branched PFAS isomerides). The present study provides a novel approach for profound insight into the uptake of PFASs by crops under complex PFAS-crop-soil interactions, aiming to ensure food safety and human health.

Highly Efficient and Simultaneous Analysis of Three Common Fluorotelomer Alcohols in Vegetables and Soils.

Fluorotelomer alcohols (FTOHs), as precursors of perfluoroalkyl carboxylic acids, are difficult to analyze due to their high volatility and matrix interference. A method based on single-factor experiments and response surface methodology design was developed for simultaneous analysis of three common FTOHs in vegetables and soils, using single extraction, dispersive solid phase extraction cleanup, and gas chromatography-mass spectrometry in negative chemical ionization. The method improved the extraction efficiency up to ∼40 folds and showed a commendable linearity range (1-100 ng/mL, R2 > 0.991), low limit of detection (0.025-0.897 ng/g, dry weight (dw)), and high accuracy and precision (83 ± 7.2-117 ± 6.0% recoveries at 2-20 ng/g fortification levels). It was successfully applied to determine the FTOHs in real vegetables and soils, demonstrating its feasibility for routine analysis. Concentrations of the FTOHs ranged from 3.5 to 37.9 ng/g (dw) and from 6.5 to 141.0 ng/g (dw), respectively, in the vegetables and soils collected nearby fluorochemical factories, which warrants further investigations on FTOH pollution and food safety concerns for which the developed method will be useful.

[Efficacy of trsatuzumab (Herceptin) combined with FOLFIRI regimen in the treatment of HER2-positive advanced gastric cancer].

OBJECTIVE: To evaluate the safety and efficacy of trsatuzumab (Herceptin) combined with FOLFIRI regimen (irinotecan plus 5-FU/LV) in the treatment of HER2-positive advanced gastric cancer. METHODS: T Thirty-four patients with pathologically confirmed advanced gastric cancer, all positive for the human epidermal growth factor receptor 2 (HER2) as identified by immunohistochemistry and fluorescence in situ hybridization, were randomized into the test group and control group to for treatment with the combined regimen and the FOLFIRI regimen alone, respectively. FOLFIRI regimen was administered every 2 weeks for 2 to 4 cycles. Trsatuzumab was given intravenously on a weekly basis with an initial dose of 4 mg/kg and a subsequent dose of 2 mg/kg. All the patients were assessed for efficacy and toxicity of the treatments. RESULTS: The overall response rate was 58.8% in the test group and 35.3% in the control group, with disease control rates of 88.2% and 64.7%, respectively, showing significant differences between the two groups (P<0.05). The most frequent grade I/II treatment-related adverse events included diarrhea, nausea/vomiting and neutropenia. CONCLUSION: Trsatuzumab combined with FOLFIRI regimen is effective, safe and well tolerated for treatment of HER2-positive advanced gastric cancer.