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A thiourea functionalised fluorescent probe 1-phenyl-3-(pyridin-4-yl)thiourea was synthesized and utilised as a fluorescent turn-on chemosensor for the selective recognition of Hg2+ ion over competitive metal ions including Na+, Mn2+, Li+, Cr2+, Ni2+, Ca2+, Cd2+, Mg2+, K+, Co2+, Cu2+, Zn2+, Al3+ and Fe2+ ions based on the inter-molecular charge transfer (ICT). Intriguingly, the receptor demonstrated unique sensing capabilities for Hg2+ in DMSO: H2O (10:90, v/v). The addition of Hg2+ ions to the sensor resulted in a blue shift in the absorption intensity and also enhancement in fluorescence intensity at 435 nm. Fluorescence emission intensity increased linearly with Hg2+ concentration ranging from 0 to 80 µL. The detection limit and binding constant were determined as 0.134 × 10-6 M and 1.733 × 107 M-1, respectively. The sensing behavior of Hg2+ was further examined using DLS, SEM and FTIR. The probe could detect Hg2+ ions across a wide pH range. Furthermore, the receptor L demonstrated good sensing performance for Hg2+ in bovine serum albumin and actual water samples.
RESUMO
A great deal of effort has been put into developing a novel and cost-effective molecular probe for selective and sensitive recognition of trace amounts of water in organic solvents due to their tremendous advantages in industrial, pharmaceutical, and laboratory-scale chemistry. Herein, a cost-effective chemosensor L has been designed and studied for the detection of trace amounts of water. The addition of water to the DMSO solution of L exhibited an enhancement of fluorescence emission at 460 nm along with a color change from green to colorless. The spectral and color changes occurred due to the self-aggregation of L. The interaction between water and L was performed by dynamic light scattering (DLS), scanning electron microscope (SEM) and finally complemented by quantum mechanical calculation. The detection limit was found to be 0.0093 wt% in DMSO. The L also exhibits a fast visual response and is effectively applied to detect trace amounts of moisture in various food materials (salt, sugar, wheat and honey) and building materials (cement, fly ash, limestone and sand).
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The 2,4-dinitrophenylhydrazine based Schiff base (L) acts as an effective fluorescence sensor for the selective detection of maleic acid. The detection limit of L towards maleic acid is observed to be 1.29 × 10-7 M. A 1:1 binding stoichiometry between L and maleic acid was obtained using Bensi-Hilderbrand method. The binding constant (Ka) was measured to be 5.17 × 106 M-1. The sensing behavior of L was confirmed through analysis using FT-IR, DLS and SEM analysis, alongside DFT calculations. Theoretical assessments clearly suggest that the L's mono-protonation and complexation in the solvent medium are the primary mechanisms in the sensing process. Additionally, L is used to imaging the maleic acid in living cells, demonstrating its potential biological uses. In addition, recognition of maleic acid in food additives was reported.
RESUMO
In this study, we aimed to explore the interaction mechanism between bovine serum albumin (BSA) and a Schiff base compound derived from 2,4-dinotrophenyl hydrazine (L) using various spectroscopic techniques. The interaction between BSA and synthesizing molecule can provide insights into binding affinity, conformational changes and potential applications in drug delivery or biochemistry. The interaction between BSA and L was studied by using UV-Vis and fluorescence titration analysis. The fluorescence quenching emission was observed at 343 nm, upon addition of L to the buffer solution of BSA. The binding between BSA and ligand is static in nature using fluorescence quenching emission. The thermodynamic parameters were calculated from the temperature-dependent binding constants (i.e., ∆H = -0.318 kcal/mol, ∆G = -7.857 kcal/mol and ∆S = 0.023 kcal/mol), which indicated that the protein-ligand complex formation between L and BSA is mainly due to the electrostatic interactions. The experimental and theoretical results showed excellent agreement with respect to the mechanism of binding and binding constants. The molecular docking and molecular dynamic analysis experiments were performed to establish the interaction between protein and ligand.
RESUMO
Recent technological strides, including high-frequency probes and lung ultrasound, have become a crucial non-invasive diagnostic tool in neonatal care, revolutionizing how respiratory conditions are assessed in the neonatal intensive care unit (NICU). High-frequency probes and portable devices significantly enhance the effectiveness of lung ultrasound in identifying respiratory distress syndrome (RDS), pneumonia, and pneumothorax, and underscore its growing significance. This comprehensive review explores the historical journey of lung ultrasonography, technological advancements, contemporary applications in neonatal care, emerging trends, and collaborative initiatives, and foresees a future where personalized healthcare optimizes outcomes for neonates.