Excitation-independent and fluorescence-reversible N-GQD for picomolar detection of inhibitory neurotransmitter in milk samples ‒ an alleyway for possible neuromorphic computing application.

N‒GQDs with an average size of ca. 20-30 nm are utilized for the picomolar detection of inhibitory neurotransmitters, glycine (Gly), in pH ca. 7.0. The crystalline nature, morphology, elemental composition, and chemical state of N-GQDs are investigated by XRD, FE-SEM, HR-TEM, XPS, and FT-IR techniques. The addition of Gly (100 × 10-9 M; 0 â†’ 1.0 mL) steadily quenches the fluorescence intensity of N-GQD (1 × 10-6 M) at 432 nm (λex 333 nm) due to inner filter effect (IFE) through the formation of ground-state complex, N-GQD•Gly. The excitation-independent N‒GQDs showed an outstanding selectivity and sensitivity towards Gly with binding constant (Ka = 8.97 × 10-3 M-1) and LoD (21.04 pM; S/N = 3). Time-correlated single-photon counting experiment confirms the static quenching of N-GQD (8.77 â†’ 8.85 ns) in the presence of Gly. The interference of other amino acids on the strong binding of the N-GQD•Gly complex in H2O is examined. Combinatorial Ex-OR and NOT gate logic circuits that could be useful in neuromorphic computing are developed based on the reversible fluorescence intensity changes of N-GQD upon the addition of Gly (ФF 0.54 â†’ 0.39). The real-time application of N-GQD was investigated using commercially available relevant milk samples. Remarkably, not less than 99% cytotoxic reactivity of N-GQDs is attained against HeLa cells.

Accidental ingestion of molar band and its management: maintenance is better than management.

Ingestion of a broken part of fixed orthodontic appliance is a potential complication during orthodontic treatment. We report a case of accidental ingestion of molar band and its subsequent diagnosis followed by endoscopic retrieval method. Although prevention of such incidence is the best method at the same time management of such an event is also crucial. The objective of this paper is to draw attention to the potentially serious complications that can occur if preventive techniques are not practiced and also the management of such event.