Gamma-ray irradiation as an effective method for mitigating antibiotic resistant bacteria and antibiotic resistance genes in aquatic environments.

The prevalence of antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (MWTPs) has emerged as a significant environmental concern. Despite advanced treatment processes, high levels of ARGs persist in the secondary effluent from MWTPs, posing ongoing environmental risks. This study explores the potential of gamma-ray irradiation as a novel approach for sterilizing antibiotic-resistant bacteria (ARB) and reducing ARGs in MWTP secondary effluent. Our findings reveal that gamma-ray irradiation at an absorbed dose of 1.6 kGy effectively deactivates all culturable bacteria, with no subsequent revival observed after exposure to 6.4 kGy and a 96-h incubation in darkness at room temperature. The removal efficiencies for a range of ARGs, including tetO, tetA, blaTEM-1, sulI, sulII, and tetW, were up to 90.5% with a 25.6 kGy absorbed dose. No resurgence of ARGs was detected after irradiation. Additionally, this study demonstrates a considerable reduction in the abundances of extracellular ARGs, with the transformation efficiencies of extracellular tetracycline and sulfadiazine resistance genes decreasing by 56.3-81.8% after 25.6 kGy irradiation. These results highlight the effectiveness of gamma-ray irradiation as an advanced and promising method for ARB sterilization and ARG reduction in the secondary effluent of MWTPs, offering a potential pathway to mitigate environmental risks associated with antibiotic resistance.

Highly efficient removal and detoxification of phenolic compounds using persulfate activated by MnOx@OMC: Synergistic mechanism and kinetic analysis.

Persulfate-based advanced oxidation technology exhibits great potential for hazardous organic pollutant removal from wastewater. Acceleration of pollutant degradation needs to be elucidated, particularly for heterogeneous catalytic systems. In this study, manganese oxide ordered mesoporous carbon composites (MnOx@OMC) were prepared by nano-casting method and used for persulfate activation to degrade phenol. Kinetics analysis indicate that the rate of phenol degradation using MnOx@OMC composites was improved by 34.9 folds relative to that using a mixture of MnOx and OMC. The phenol toxicity towards Caenorhabditis elegans could be totally reduced within 8 min. The different roles of MnOx and OMC in persulfate activation were confirmed to validate their synergistic effect. MnOx provided major active sites for persulfate activation in accordance with the surface Mn3+/Mn4+ cycle to induce SO4•- radicals. The OMC matrix provided the adsorption sites to enrich phenol molecules on the catalytic surface and promote the interfacial electron transfer process for persulfate activation. Moreover, a novel kinetic model with two distinct kinetic stages was established to verify the effects of phenol and persulfate on phenol removal.

A New Intraoperative Syndesmosis Instability Classification System: Utility and Medium-term Results in Closed Displaced Ankle Fractures.

OBJECTIVE: To investigate the utility and medium-term results of a new intra-operative classification system for distal tibiofibular syndesmosis injury in ankle fractures. METHODS: Between January 2010 and January 2015, 116 patients diagnosed with displaced closed Weber B and C ankle fractures were treated in our department. The etiology of injury was 56 cases of fall-sprain, 36 of traffic injury, 14 of fall from a height, and 10 of multiple injuries. After fixation of the fibular fracture, we classify syndesmosis stability as either normal or one of three grades of instability using the fibular hook traction test. This determined further fixation selection and final syndesmosis treatment. RESULTS: Of 116 cases, 82 (71%) demonstrated a tibiofibular syndesmosis injury and 52 (45%) were unstable. Twenty-six cases were type I injuries (<4 mm displacement), 41% cases were type II injuries (4-7 mm displacement), and 3% of cases were type III injuries (>7 mm displacement). Types II and III are defined as unstable and require stabilization. Type III injuries have multiplanar instability and require two screws at the syndesmosis. Weber C fractures demonstrate significantly greater degrees of instability than Weber B fractures (χ2 = 15.50, P = 0.0014). All patients were followed up for 12-24 months, with no cases of non-union or broken screws. Good and excellent results were achieved in 93% of cases (according to the American Orthopaedic Foot and Ankle Society scoring system). CONCLUSION: The syndesmosis instability classification system provides a rational and efficient basis for managing syndesmosis instability. Our results from application of the algorithm justify its further evaluation in the treatment of patients with closed displaced Weber B and C ankle fractures.

Determination of autoinducer-2 in biological samples by high-performance liquid chromatography with fluorescence detection using pre-column derivatization.

Autoinducer-2 (AI-2), as a small-molecular-weight organic molecule secreted and perceived by various bacteria, enables intra- and inter-species communications. Quantitative determination of AI-2 is essential for exploring the bacterial AI-2-related physiological and biochemical processes. However, current strategies for sensitive detection of AI-2 require sophisticated instruments and complicated procedures. In this work, on the basis of the derivatization of AI-2 with 2,3-diaminonaphthalene, a simple, sensitive and cost-effective high-performance liquid chromatography with fluorescence detector (HPLC-FLD) method is developed for the quantitative detection of AI-2. Under the optimized conditions, this method had a broad linear range of 10-14,000 ng/ml (R(2)=0.9999), and a low detection limit of 1.0 ng/ml. Furthermore, the effectiveness of this approach was further validated through measuring the AI-2 concentrations in the cell-free culture supernatants of both Escherichia coli and Vibrio harveyi.