Organic ligands activate the dark formation of hydroxyl radicals (HO•) in surface soil/sediment: Yields, mechanisms, and applications.

Soil is an important sink for various pollutants. Recent findings suggest that soil and sediment would spontaneously form HO• through Fenton or Fenton-like reactions under natural conditions. In this study, the effects and mechanisms of organic ligands (OLs) on the occurrence of HO• in surface soil/sediment were experimentally and computationally examined. Results confirmed that HO• generation was ND-12.92 nmol/g in surface soil/sediment, and the addition of EDTA-2Na would significantly enhance the yields of HO• by 1.4-352 times. Moisture was the decisive factor of soil HO• generation. The release of Fe(II) from solid into the aqueous phase was essential for the stimulation of HO• in EDTA-2Na suspensions. Furthermore, complexation reactions between Fe(II) and OLs would enhance single electron transfer (SET) reactions and the formation of O2•-. Interestingly, for specific OLs, their stimulations on SET and formation of O2•- would depress HO• generation. Provoking HO• generation by OLs could be efficiently used to degrade sulfamethoxazole in rice field sediment. The study provided new knowledge on how commonly synthetic OLs affect the HO• generation in surface soil/sediment, and it additionally shed light on the engineered stimulation of in-situ Fenton reactions in natural soil/sediment.

The study on psychological resilience of tinnitus and associated influencing factors.

The association between tinnitus and psychological resilience is an underdeveloped area of research. This cross-sectional study investigated such associations and factors potentially affecting resilience in 61 patients. Demographic and psychometric data were collected by questionnaires. The Connor-Davidson Resilience Scale (CD-RISC), Medical Coping Modes Questionnaire (MCMQ), Satisfaction with Life Scale (SWLS), General Self-Efficacy Scale (GSES), Big Five Inventory (BFI) and Perceived Social Support Scale (PSSS) were completed by participants. Data were analyzed using independent t-test and Pearson's correlation analysis and multiple linear regression modeling. The CD-RISC score was relatively low (66.97 ± 15.71), negatively correlated with tinnitus (r = -0.276, p < 0.001) and associated with age (r = 0.270，P＜0.001). As protective factors, SWLS (r = 0.486, p < 0.001), GSES (r = 0.555, p < 0.001), PSSS (r = 0.538, p < 0.001) and extraversion were positively correlated with CD-RISC and BFI scores (r = 0.287, p < 0.001). We also detected a negative correlation with neuroticism (r = -0.395, p < 0.001), which is a known risk factor for worse CD-RISC scores. Identifying protective and risk factors for psychological resilience can be used to predict treatment outcomes in tinnitus patients, which will help devise personalized solutions and improve patients' quality of life.

Pivotal role of water molecules in the photodegradation of pymetrozine: New insights for developing green pesticides.

Photodegradation of the insecticide pymetrozine (PYM) was studied on surface of wax films, and in aqueous and nonaqueous phase. The half-life of PYM on the wax surface was approximately 250 times longer than in water. Scavenging experiments, laser flash photolysis, and spectra analysis indicated the first singlet excited state of PYM (S1 *PYM) to be the most important photoinduced species initiating the photodegradation. Quantum chemistry calculations identified significant molecular torsion and changes in the structure C-CN-N of S1 *PYM, and the absolute charges of the CN atoms increased and the bond strength weakened. Free energy surface analysis, and O18 labeling experiments further confirmed that the mechanism was two-step photoinduced hydrolysis. The first step is the hydrolysis of S1 *PYM at CN upon reaction with 2-3 water molecules (one H2O molecule as the catalyst). The second step is an intramolecular hydrogen transfer coupled with the cleavage of C-N bond and formation of two cyclic products. During the interactions, water molecules experience catalytic activation by transferring protons, while there is a negligible solvent effect. Clarifying the detailed photodegradation mechanisms of PYM is beneficial for the development of green pesticides that are photostable and effective on leaf surfaces, and photolabile and detoxified in the aquatic environment.

Spatial and seasonal variations of antibiotic resistance genes and antibiotics in the surface waters of Poyang Lake in China.

Antibiotic resistance genes (ARGs) and antibiotics in the aquatic environment raise health concerns particularly on the dispersal and persistence of antibiotic resistance. Large lakes, which serve as catch basins of anthropogenic inputs provide an ideal environment for understanding the occurrence and accumulation of ARGs and antibiotics in freshwater environments. Here, the largest freshwater lake in China, Poyang Lake, located in the developing district of Yangtze valley was used to study the characterization of the spatial and seasonal variation of both ARGs and antibiotics. Results showed that twelve tested ARGs (sul1, sul2, sul3, tetA, tetB, tetC, tetH, tetW, tetO, tetM, qnrS, and qnrB) were detected in the surface waters of Poyang Lake, with a detection frequency ranging from 19.2% to 100%, and sul2 and tetA genes were identified as potential indicators of ARG pollution in this region. Among the 11 analyzed antibiotics, sulfonamides were the predominant antibiotics with a contribution of more than 50% to the total concentrations of tested antibiotics. The total concentrations of both ARGs and antibiotics were higher in the dry season than those in the wet season. Furthermore, ARGs and antibiotics in the surface waters also varied with sampling locations, being consistently at riverine tributaries. Positive correlations were also observed between the concentrations of ARGs and antibiotics, as well as the integron gene (intI1), indicating that antibiotics and intI1 may be playing important roles in the occurrence and dispersal of ARGs in the surface waters. Lastly, our results suggest that intensive anthropogenic activities related to antibiotic usage have substantially contributed to the occurrence and persistence of ARGs and antibiotics in Poyang Lake.

Levels and human health risk assessments of heavy metals in fish tissue obtained from the agricultural heritage rice-fish-farming system in China.

China began to practice Rice-fish-farming system (RFFS) 1700 years ago. Nowadays, the widely spread of metals could be potential threats to the quality of RFFS fish. In this study, Pb, Cd, Hg, As and Cr as the top five most toxic heavy metals were determined in six species of RFFS fish meat obtained from 7 provinces in south China. The mean concentrations of metals in RFFS fish followed Pb (36.89 µg/kg) > As (33.36 µg/kg) > Cr (18.54 µg/kg) > Hg (16.35 µg/kg) > Cd (2.01 µg/kg), which were mostly lower in comparison with fish from traditional aquaculture systems raised by fish feeds. Grass carp obtained lower metal concentrations compared with other fishes, possibly indicating the importance of feeding habits of RFFS fish. Concentrations of metals in fish and RFFS sediment were in good correlations, and benthic fish obtained high pollution levels, suggesting the accumulation of metals through the direct contact with sediment. Risks assessments coupled with Monte Carlo simulation indicated the potential non-carcinogenic risks and carcinogenic risks decreased following As > Hg > Cr ≈ Pb > Cd, and As > Cr > Cd > Pb, respectively. These results suggested RFFS is still a successful mode of green agriculture.

[Application of endoscopic nasal lateral wall dissection in lesions of the maxillary sinus].

OBJECTIVE: To investigate the application of endoscopic nasal lateral wall dissection in lesions of the maxillary sinus. METHOD: Ten hospitalized patients with the maxillary sinus lesions were treated with the endoscopic nasal lateral wall dissection. RESULT: All 10 patients were unilateral invasion. Among them, 7 cases were inverted papilloma, 2 cases were recurrent antrochoanal polyps, 1 case was sinusal tooth. The tumors and antrochoanal polyps originated from the every part of the maxillary sinus wall during operation, especially from the anterior and media wall. During 10-62 months follow-up,epithelization of nasal occured and the shape of inferior turbinate was well. All of them had no epiphora. CONCLUSION: Endoscopic nasal lateral wall dissection can remain the function of nasal lacrimal duct and nasal cavity,and may provide a new minimally invasive approach for complete resection of lesions of nasal cavity and the maxillary sinus.