Decomposition of microplastics using copper oxide/bismuth vanadate-based photocatalysts: Insight mechanisms and environmental impacts

To mitigate marine pollution, we improved the photo-Fenton reaction of modified nanoscale CuO/BiVO4 photocatalysts to resolve the challenge of efficient microplastic degradation in wastewater treatment. Material property analysis and computational results revealed that deposition of CuO onto BiVO4 nanocomposites improved photocatalytic activity by promoting an excess of electrons in CuO and surface charge transfer, resulting in an increased production of e--h+ for ROS generation via H2O2 activation. 1O2 was dominated and identified through quenching experiments, XPS analysis, and EPR. ROS generation increased via H2O2 activation, causing major surface abrasion and increased carbonyl and vinyl indices in microplastics. Treated water had minimal impact on Lycopersicon esculentum Mill. seedling growth but caused considerable mortality in cell lines and Moina macrocopa mortality at greater dosages due to their sensitivity to ions and H2O2 residuals. Overall, this treatment can effectively degrade microplastics, but the dilution of treated water is still needed before being discharged.

Pharmacokinetics of amoxicillin trihydrate in Thai swamp buffaloes (Bubalus bubalis): a pilot study

This study aimed to investigate the pharmacokinetic characteristics of amoxicillin (AMX) in Thai swamp buffaloes, Bubalus bubalis, following single intramuscular administration at two dosages of 10 and 20 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 48 h. The plasma concentrations of AMX were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of AMX in the plasma were determined up to 24 h after i.m. administration at both dosages. The C_max values of AMX were 3.39 ± 0.18 μg/mL and 6.16 ± 0.18 μg/mL at doses of 10 and 20 mg/kg, respectively. The AUC_last values increased in a dose-dependent fashion. The half-life values were 5.56 ± 0.40 h and 4.37 ± 0.23 h at doses of 10 and 20 mg/kg b.w, respectively. Based on the pharmacokinetic data and PK-PD index (T > MIC), i.m. administration of AMX at a dose of 20 mg/kg b.w might be appropriate for the treatment of susceptible Mannheimia haemolytica infection in Thai swamp buffaloes.

Dispositions and residue depletion of enrofloxacin and its metabolite ciprofloxacin in muscle tissue of giant freshwater prawns (Macrobrachium rosenbergii)

Fates and residue depletion of enrofloxacin (ER) and its metabolite ciprofloxacin (CP) were examined in giant freshwater prawns, Macrobrachium rosenbergii, following either single oral (p.o.) administration of ER at a dosage of 10 mg/kg body weight (b.w.) or medicated-feed treatment at the feeding concentration of 5 g/kg of feed for five consecutive days. The concentrations of ER and CP in prawn muscle tissues were measured simultaneously using high-performance liquid chromatography (HPLC) equipped with a fluorescence detector. Muscle tissue concentrations of ER and CP were below the detection limit (LOD, 0.015 microg/g for ER; 0.025 microg/g for CP) after 360 and 42 h, following single p.o. administration respectively. Peak muscle concentration (C(max)) of ER was 1.98 +/- 0.22 microg/g whereas CP was measurable at concentrations close to the detection limit of the analytical method after p.o. administration at a single dosage of 10 mg/kg b.w. The concentration of ER in prawn muscle tissue with respect to time was analyzed with a non-compartmental pharmacokinetic model. The elimination half-life and area under the curve of ER were 39.33 +/- 7.27 h and 168.7 +/- 28.7 microg x h/g after p.o. administration at a single dose of 10 mg/kg x b.w. respectively. In medicated-feed treated group, ER was detectable in prawn muscle tissue 11 days postdosing at the dose of 5 g/kg of feed for five consecutive days, which is the value corresponding to the maximum residue limit (MRL) of ER in animal products. The maximum concentrations of ER and CP were 2.77 +/- 0.91 and 0.06 +/- 0.006 microg/g during medicated-feed treatment and postdosing respectively. The values of elimination half-life and absorption half-life of ER after single p.o. administration at a dosage of 10 mg/kg b.w. corresponded well with the values determined from medicated-feed treated group, showing 41.01 +/- 6.62 and 11.36 +/- 3.15 h respectively in M. rosenbergii. Based on data derived from this study, to avoid the ER residue in prawn muscle, it should take at least 11 days postcessation of medicated feed containing ER at the dose concentration of 5 g/kg of feed twice a day at a rate of 1% of total body weight for five consecutive days to wash out the drug from the muscle of M. rosenbergii.