Highly sensitive fluorescent quantification of carbendazim by two-dimensional Tb-MOF nanosheets for food safety.

Carbendazim (CBZ), a well-known benzimidazole pesticide, is utilized in agriculture to prevent and cure plant diseases caused by fungi. Residual CBZ in food poses serious threat to human health. Herein, a fluorescent two-dimensional terbium-based metal-organic framework (2D Tb-MOF) nanosheet sensor was developed for the rapid and ultrasensitive detection of CBZ. The 2D Tb-MOF nanosheets, prepared with Tb3+ ions and 5-borono-1,3-benzenedicarboxylic acid (BBDC) as the precursors, exhibited excellent optical properties. Upon the addition of CBZ, the fluorescence of Tb-MOF nanosheets was quenched because of the inner filter effect (IFE) and dynamic quenching. The fluorescence sensor offered two linear ranges of 0.06-4 and 4-40 µg/mL with a low detection limit of 17.95 ng/mL. Furthermore, the proposed sensing platform was successfully applied to assay CBZ in apples and tea, and satisfactory results were obtained. This study provides an effective alternative strategy for the qualitative and quantitative determination of CBZ to ensure food safety.

A case of a death caused by an atrial-oesophageal-thoracic fistula after radiofrequency ablation of atrial fibrillation.

The report is about a 49-year-old man with rheumatic heart disease and atrial fibrillation. He underwent mitral valve replacement, tricuspid valvuloplasty, and atrial fibrillation radiofrequency ablation in the hospital. He vomited blood on the 2nd postoperative day, and the bleeding gradually worsened thereafter. He had to have repeated drainage of large amounts of blood from his right thoracic cavity and digestive tract. He died suddenly after undergoing an oesophageal endoscopy on the 24th postoperative day. The autopsy revealed an atrial-oesophageal-thoracic fistula. By excluding the possibility of the fistula being caused by complications from nasoenteric feeding, tracheal intubation, and a foreign body ingestion, we determined that the atrial-oesophageal-thoracic fistula was a complication after radiofrequency ablation according to the finding of coagulation necrosis of the myocardial cells at the left atrium fistula. In addition, we also performed an elemental analysis on the radiofrequency ablation area and other cardiac tissues by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and found five metal elements, Cr, Cu, Zn, Mn, and Ti, which specifically existed in the radiofrequency ablation area. This finding has the potential to serve as new evidence for radiofrequency ablation and is a worthy direction of research.

Fluorescent lanthanide metal-organic framework for rapid and ultrasensitive detection of methcathinone in human urine.

Methcathinone (MC), a new and easily abused psychoactive substance, not only has a rigorous impact on public security, but also endangers people's health. Herein, novel fluorescent europium metal-organic frameworks (Eu-MOF) were synthesized through a facile one-step solvothermal strategy and utilized as an effective "signal-off" sensing platform for rapid and ultrasensitive detection of MC. The as-fabricated Eu-MOF possessed superior optical properties encompassing bright red fluorescence and good photostability. In the presence of MC, the fluorescence of Eu-MOF was significantly quenched, mainly attributing to the internal filtering effect between Eu-MOF and MC. The fluorescent signal showed high selectivity for MC over other illicit drugs, and offered two linear ranges of 1-100 ng/mL and 100-4000 ng/mL with a detection limit of 0.40 ng/mL. Strikingly, the nanoprobe could be applied for the assay of MC in human urine with satisfactory recoveries and acceptable results. This work provides a promising route for MC detection to effectively control illicit drug pandemic worldwide.