查看更多>>摘要：Indenocarbothioamides 2, obtained from reaction of indane-1,3-dione with aryl isothiocyanates, on condensation with 3-chloropentane-2,4-dione and chloroacetyl chloride furnished 1,3-indanedione coupled thiazole and thiazolidin-5-one derivatives, respectively. The structure of the obtained products was assigned on the basis of spectral data (IR, NMR and Mass). Prototropic tautomerism studies of carbothioamides 2 were carried out in solution (H-1 NMR, C-13 NMR and UV-vis), gas phase (Mass) and solid state (IR and X-ray). X-ray diffraction studies of carbothioamide 2a have revealed the existence of enolic form in the solid state. DFT studies of various possible tautomeric forms in gas phase as well as in solution state corroborated by the experimental results. Antibacterial studies of indenothiazole and indenothiazolidin5-one derivatives have been reported. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Illegal additives can bring the economic benefit, resulting in the continuous irregularities in the use of illegal additives. In this study, a method for rapid, sensitive, and simultaneous detection of multiple illegal additives including enrofloxacin, malachite green, nitrofurazone, and Sudan I in feed and food samples by surface-enhanced Raman spectroscopy (SERS) with Cu2O-Ag/AF-C3N4 composite substrate was developed. A Cu2O-Ag/AF-C3N4 composite substrate was prepared by reacting Cu2O modified by AFC3N4 nanosheets with AgNO3 solution. The substrate has a limit of detection (LOD) of 1.29 x 10(-6) mg/ L, a good linear relationship of between 10-6 and 10-2 mg/L, and an R2 value of 0.95 for Rhodamine B detection. Furthermore, the substrate showed high uniformity and reproducibility, with relative standard deviations (RSD) of 6.74% and 4.85%, respectively. Adding AF-C3N4 nanosheets not only increased the enhancement effect of the substrate, which was 4.4 times of that before addition, but also endowed it with good self-cleaning characteristics owing to its excellent photocatalytic activity. The substrate can be reused, with over 80% of the original Raman signal strength remaining after four repeat uses. The SERS based on the above substrate was used to detect the illegal additives, the LOD of enrofloxacin, malachite green, nitrofurazone, and Sudan I can reach 4.67 x 10(-4) mg/L, 2.57 x 10(-5) mg/L, 5.7 x 10(-7) mg/L and 6.92 x 10(-5) mg/L. The results reveal that this substrate has great application potential in feed and food safety.(C) 2022 Published by Elsevier B.V.
查看更多>>摘要：The norfloxacin (NFX) residue in milk will increase human resistance to drugs and pose a threat to public health. In this work, a highly sensitive method for detection of NFX was developed based on surface enhanced Raman spectroscopy (SERS) using beta-cyclodextrin functionalized silver nanoparticles (beta-CDAgNPs) as substrate. The unique spatial size and hydrophilicity of beta-CD on the surface of AgNPs could selectively capture the target molecule (NFX) through some weak interactions, including hydrogen-bond interaction, electrostatic interaction, etc. The interactions were characterized by the UV-Vis absorption spectroscopy, fluorescence spectroscopy, Zeta potential and DLS. The Raman signal of NFX is largely enhanced when anchored by beta-CD on the surface of AgNPs due to SERS effect. Through a series of experiments and analysis, the limit of detection (LOD) in standard solution and spiked milk were calculated to be 3.214 pmol/L and 5.327 nmol/L. The correlation coefficients (R-2) were 0.986 and 0.984, respectively. For milk sample determination of NFX, the recovery was 101.29% to 104.00% with the relative standard deviation (RSD) from 2.986% to 9.136%. To sum up, this developed SERS strategy is sensitive and specific to detect NFX in milk, it has practical application value and prospects. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Sensitive and selective detection of 2,4,6-trinitrotoluene (TNT) is critical for environmental protection and public health. In this work, a convenient synthesis strategy for preparation of fluorescent PEI-AgNCs was described and further a facile and label-free sensing strategy for detection of TNT was devel-oped. The hyperbranched polyethyleneimine (PEI) were used as template to one-step synthesize func-tional PEI-AgNCs with bright fluorescence signal and rich amino groups on their surface. PEI can specifically bind to electron-deficient TNT through donor-receptor interaction to form Meissenheimer complex. Interestingly, the absorption spectra of the Meissenheimer complex overlap with the fluores-cence emission peak of PEI-AgNCs, thus quenching fluorescence of PEI-Ag NCs through fluorescence resonance energy transfer (FRET). Furthermore, this bonding process also initiate aggregation of PEIAgNCs and quench the fluorescence of PEI-AgNCs by the aggregation-induced quenching (AIQ) effect. The novel method demonstrates sensitivity with a detection limit for TNT have been obtained as 17 nM. In addition, the proposed sensing method also has good selectivity over other potential interference and displayed a good potential application value in real water samples with satisfactory recoveries, offering a promising platform for sensing TNT in public safety and security environment protection.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：ROS is a significant factor in the cancer treatment mechanism. The monitoring anticancer-associated H2O2 level plays a vital role in the anticancer mechanistic exploration in pathology and physiology. Herein we synthesized a ratiometric fluorescent probe (HBQ-L) to detect and image H2O2 based on excited-state intramolecular proton transfer. HBQ-L had a high sensitivity (231-fold) with a low detection limit (28.5 nM) for monitoring H2O2 in solution. HBQ-L showed good mitochondrial-targeting and successfully detected both exo-/endogenous H2O2 in A549 cells. Furthermore, HBQ-L was used to ratio metric monitor H2O2 level in anticancer reagent DOX-treated cells or zebrafish. Importantly, it was employed to access the monitoring H2O2 in the A549 tumor-bearing mice. (C) 2022 Elsevier B.V. All rights reserved.& nbsp;
查看更多>>摘要：Biowaste based nanoadsorbents have gained much attention in the recent times for wastewater decolourization owing to their low cost, high surface area and high adsorption capacities. In the present research, garlic peel based nanoparticles (GCNP) were synthesized at different temperatures by a one step pyrolytic green approach for the effective removal of cationic dye, malachite green from the aqueous medium. The surface properties of Garlic nanoparticles were elucidated by N-2 adsorption-desorption and all the GCNP samples were found to exhibit Type IV(a) isotherm indicating the presence of mesopores in carbon matrix. Using BET calculations, highest surface area (380 m(2)/g) was obtained for GCNP synthesized at 1000 & nbsp;C. Characterization of nanoparticles was done by XRD, EDAX, SEM and FTIR studies before and after the dye treatment. Adsorption studies conducted using different parameters like contact time, concentration and pH and dosage of adsorbent showed removal efficiency above 90% for the contact time of 70 min. Best adsorption experimental results were obtained for GCNP synthesized at 1000 & nbsp;C ascribable to its high surface area, higher total pore volume (0.26 cm2/g) and higher carbon content. Four adsorption isotherm models were used to validate batch equillibrium studies and the results showed data in good agreement with Langmuir and Freundlich isotherms with maximum Langmuir adsorbtion capactiy to be 373.7 mg/g. Kinetic modelling of the data showed best fit with the Pseudo second order model with rate constant value of 48.726 g mg(-1)& nbsp;min(-1). Regenerative studies were conducted conducted upto 6 cycles. Also the GC nanoparticles were tested for their compatibility in membrane form wherein, removal efficiency results were obtained for GCNP anchored in polyvinyl difluoride (PVDF) and polysulfone (PSF) membrane matrix for dye adsorption. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Polymeric carbon nitride often displays weak photoluminescence in solid state due to the aggregation-caused quenching effect. Herein, highly fluorescent carbon nitride oligomer (CNO) with aggregation-induced emission (AIE) characteristic was prepared via one-step solid-phase thermal condensation of 2,4-diamino-6-phenyl-1,3,5-triazine (DPT) at 350 degrees C. CNO is mainly composed of DPT dimer connected by rotatable imine groups, and exhibits weak fluorescence in the dispersed state and strong blue -green emission in the aggregated state and solid state. Density functional theory calculations indicate that the restriction of phenyl and triazine ring twisting motions is the main origin of the AIE phenomenon of CNO. Finally, CNO was preliminarily applied for fluorescent staining of plastic pellets. This work not only provides a solid-state strategy to synthesize fluorescent material with AIE characteristic but also extends the application of polymeric carbon nitride. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Advancement in coordination chemistry has achieved an impressive development of metal organic frameworks (MOFs) as the supramolecular hybrid materials, comprising harmonized metal nodes with organic ligands. Scope and approach: MOFs offer the unique properties of easy synthesis, nanoscale structure, adjusta-ble size and morphology, high porosity, large surface area, supreme chemical tunability and stability, and biocompatibility. The features provide an exceptional opportunity for the widely usage of MOFs in the different scientific fields, e.g. biomedicine, electrocatalysis, food safety, energy storage, environmental surveillance, and biosensing platforms. The synergistic incorporation of the aptamer advantages and the superiorities of MOFs attains the novel MOF-based aptasensors. The excellent selectivity and sensi-tivity of the MOF-based aptasensors nominate them as efficient lab-on-chip tools for cost-effective, label-free, portable, and real-time monitoring of diverse targets. Key findings and conclusions: Here, we review the achievements in the sensor design by cooperation of MOF motifs and aptamers with the conspicuous potential of determining the targets. Finally, some results are expressed that provide a valuable viewpoint for developing the novel MOF-based test strips in the future. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this study, a highly sensitive colorimetric assay has been constructed for the determination of xanthine oxidase (XOD) activity by the GNP@MnO2 core-shell nanoparticles as probe. In the presence of XOD, xanthine can be oxidized to produce H2O(2), which makes the MnO2 shell fallen off. With the single particle detection (SPD) based dark field microscopy (DFM), the scattering color of GNP@MnO2 NP probe shows obvious change before and after etching process. At the single particle level, noticeable color change of the single probe can be easily detected in the existence of trace XOD. This SPD-based colorimetric strategy displays broad linear dynamic range (0.02-4 mU/mL) and low detection limit of 7.82 mu U/mL, which is more sensitive than the results from ensemble sample measurement. In addition, we tested the inhibitory effect of quercetin on the activity of XOD and obtained good inhibition effect. As a consequence, this SPD-based colorimetric strategy provides new perception for the ultrasensitive detection of molecules in complex system. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Metabolic dynamics of bacterial cells is needed for understanding the correlation between changes in environmental conditions and cell metabolic activity. In this study, Raman spectroscopy combined with deuterium labelling was used to analyze the metabolic activity of a single Escherichia coli O157:H7 cell. The incorporation of deuterium from heavy water into cellular biomolecules resulted in the formation of carbon-deuterium (CD) peaks in the Raman spectra, indicating the cell metabolic activity. The broad vibrational peaks corresponding to CD and CH peaks encompassed different specific shifts of macromolecules such as protein, lipids, and nucleic acid. The utilization of tryptophan and oleic acid by the cell as the sole carbon source led to changes in cell lipid composition, as indicated by new peaks in the second derivative spectra. Thus, the proposed method could semi-quantitatively determine total metabolic activity, macromolecule specific identification, and lipid and protein metabolism in a single cell.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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