查看更多>>摘要：In this study, Raman spectroscopy combined with convolutional neural network (CNN) and chemometrics was used to achieve the identification and quantification of honey samples adulterated with high fructose corn syrup, rice syrup, maltose syrup and blended syrup, respectively. The shallow CNNs utilized to analyze honey mixed with single-variety syrup classified samples into four categories by the adulteration concentration with more than 97% accuracy, and the general CNN model for simultaneously detecting honey adulterated with any type of syrup obtained an accuracy of 94.79%. The established CNNs had the best performance compared with several chemometric classification algorithms. In addition, partial least square regression (PLS) successfully predicted the purity of honey mixed with single syrup, while coefficients of determination and root mean square errors of prediction were greater than 0.98 and less than 3.50, respectively. Therefore, the proposed methods based on Raman spectra have important practical significance for food safety and quality control of honey products. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Pseudomonas (P.) aeruginosa is a bacterium responsible for severe infections that have become a real concern in hospital environments. Nosocomial infections caused by P. aeruginosa are often hard to treat because of its intrinsic resistance and remarkable ability to acquire further resistance mechanisms to multiple groups of antimicrobial agents. Thus, rapid determination of the susceptibility of P. aeruginosa isolates to antibiotics is crucial for effective treatment. The current methods used for susceptibility determination are time-consuming; hence the importance of developing a new method. Fourier-transform infra-red (FTIR) spectroscopy is known as a rapid and sensitive diagnostic tool, with the ability to detect minor abnormal molecular changes including those associated with the development of antibiotic- resistant bacteria. The main goal of this study is to evaluate the potential of FTIR spectroscopy together with machine learning algorithms, to determine the susceptibility of P. aeruginosa to different antibiotics in a time span of similar to 20 min after the first culture. For this goal, 590 isolates of P. aeruginosa, obtained from different infection sites of various patients, were measured by FTIR spectroscopy and analyzed by machine learning algorithms. We have successfully determined the susceptibility of P. aeruginosa to various antibiotics with an accuracy of 82-90%. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Butyrylcholinesterase (BChE) is an enzyme which is relevant to a variety of diseases, and often serve as a common biomarker of health. In this work, a novel fluorescence sensor based on redox-regulated synthesis of polydopamine nanoparticles (PDANPs) has been developed for simple and sensitive sensing BChE activity. A facile and rapid one-step approach for the preparation of fluorescent PDANPs uses potassium permanganate to oxidize dopamine. We demonstrated that the fluorescence intensity of PDANPs is dependent on the dose of potassium permanganate. Butyrylcholinesterase catalyzes the hydrolysis of butyrylthiocholine iodide (BTCh) to produce thiolcholine (TCh) which in a redox reaction with potassium permanganate prevents the formation of fluorescent PDANP. As a result, the activity of BChE can be determined in line with changes in the fluorescence of PDANPs. Based on this finding, a convenient and label free fluorescence sensor for BChE activity was established via redox-control of the fluorescence intensity of PDANPs. A dynamic response range for BChE is acquired within 0.5 ti 200 U/L along with a detection limit of 0.047 U/L. Importantly, the proposed method achieves practical application toward BChE in human sera. Moreover, its satisfying performance for screening of inhibitors was also proved. Hence, the proposed sensor holds great potential for cholinesterase-related biomedical investigation.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Introduction: To implement Hyperspectral Imaging (HSI) as a tool for quantifying inflammatory cells in tissue specimens by the example of myocarditis in a collective of forensic patients. Material and methods: 44 consecutive patients with suspected myocardial inflammation at autopsy, diagnosed between 2013 and 2018 at the Institute of ForensicMedicine, Medical University of Innsbruck, were selected for this study. Using the IMEC SNAPSCAN camera, visible and near infrared hyperspectral images were collected from slides stained with CD3 and CD45 to assess quantity and spatial distribution of positive cells. Results were compared with visual assessment (VA) and conventional digital image analysis (DIA). Results: Finally, specimens of 40 patients were evaluated, of whom 36 patients (90%) suffered from myocarditis, two patients (5%) had suspected healing/healed myocarditis, and two did no have myocarditis (5%). The amount of CD3 and CD45 positive cells did not differ significantly between VA, HSI, and DIA (p(VA/HSI/DIA) = 0.46 for CD3 and 0.81 for CD45). Cohen acute accent s Kappa showed a very high correlation between VA versus HSI, VA versus DIA, and HSI versus DIA for CD3 (Cohen acute accent s Kappa = 0.91, 1.00, and 0.91, respectively). For CD45 an almost as high correlation was seen for VA versus HSI and HSI versus DIA (Cohen acute accent s Kappa = 0.75 and 0.70) and VA versus DIA (Cohen acute accent s Kappa = 0.89). Conclusion: HSI is a reliable and objective method to count inflammatory cells in tissue slides of suspected myocarditis. Implementation of HSI in digital pathology might further expand the possibility of a sophisticated method. (c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Many natural products induce apoptotic cell death in cancer cells, though studies on their interactions with macromolecules are limited. For the first time, this study demonstrated the cytotoxic potential of usnic acid (UA) against squamous carcinoma (A-431) cells and the associated changes in cell surface proteins, lipids and DNA by attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) and dynamic light scattering (DLS) spectroscopic studies. The IC50 for UA was 98.9 mM after treatment of A-431 cells for 48 h, while the IC50 reduced to 39.2 mM after 72 h of incubation time. UA induced oxidative stress in treated cells as confirmed by DCFHDA flow cytometry assay, depletion in reduced glutathione and increase in lipid peroxidation. The oxidative stress resulted in conformation change in amide I, amide II protein bands and DNA as observed by ATR-FTIR in UA treated A-431 cells. Shift in secondary structures of proteins from a helix to 0 sheets and structural changes in DNA was observed in UA treated A-431 cells. An increase in the band intensity of phospholipids, increased distribution of lipid and change in membrane potential was noted in UA treated cells, which was confirmed by externalization of phosphatidylserine to the outer membrane by annexin V-FITC/PI assay. Increase in mitochondrial membrane potential, cell cycle arrest at G0/G1 phase by flow cytometry and activation of caspase-3/7 dependent proteins confirmed the UA induced apoptosis in treated A-431 cells. FTIR and DLS spectroscopy confirmed the changes in biomolecules after UA treatment, which were associated with apoptosis, as observed by flow cytometry. (C)& nbsp;2022 Published by Elsevier B.V.
查看更多>>摘要：In recent years, antibiotic residues in food have been of great concern to regulators and consumers. In this study, a novel fluorescent sensor based on S, N-doped carbon quantum dots (S, N-CQDs) was established for rapid detection of tetracycline antibiotics (TCs). Through the internal filter effect (IFE), QDs fluorescence can be effectively quenched by TCs, endowing it an "off" condition. Under the optimal conditions, the TC concentration in the range of 1.88-60 mu mol/L had a good linear relationship with the change of QDs fluorescence intensity, and the limit of detection (LOD) was calculated as 0.56 mu mol/L (S/N = 3). Furthermore, the proposed "Turn-off" sensor could be employed to quickly and accurately quantify TCs residues even in milk, honey and tap water. The recovery rate was as high as between 93.61% and 102.31%. The established sensor has great application value in the fields of food safety and drug analysis, and provides broad prospects for the future food industry. (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：In this work a flexible multi-dentate 4,4'-(1H-1,2,4-triazole-1-yl) methylene-bis(benzonic acid) (H2L) ligand has been employed, a unique cluster-based nano-porous luminescent zinc(II) metal-organic framework {[Zn(mu(6)-L)]center dot(DMAC)(2))(n) (1) (DMAC = Dimethylacetamide) has been isolated under solvothermal conditions. The H2L ligand adopts hexa-dentate coordination modes via one triazole nitrogen atom and four aromatic carboxylate oxygen atoms, which bridge the neighboring six-coordinated Zn-II centers, leading to a three-dimensional (3D) nano-porous metal organic framework. A PLATON program analysis suggests the total potential solvent area volume is 2028.9 angstrom(3), which occupy 62.5% percent of the unit cell volume (3248.4 angstrom(3)). PXRD Patterns of the as-synthesized samples 1 have been determined confirming the purity of the bulky samples. Photo-luminescent properties indicate strong fluorescent emissions of 1 at the room temperature. Further photo-luminescent measurements show that 1 can exhibit highly sensitive real-time luminescence sensing of anthrax biomarker dipicolinic acid (DPA) with high quenching efficiency (K-SV = 1.48 x 10(5) M-1) and low detection limit (0.298 mu M (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive luminescence sensing for Cr2O72- ions in aqueous solutions with high quenching efficiency K-SV = 1.22 x 10(4) L.mol(-1) and low detection limit (0.023 mu M (S/N = 3)). Therefore 1 can be used a unique multi-functional 3D cluster-based metal organic material in sensitive detection and effective detection of environment pollutants and biomarker molecules. (C) 2022 Elsevier B.V. All rights reserved.
Mazeikien, ReginaNiaura, GediminasMalinauskas, Albertas
11页
查看更多>>摘要：A detailed study on Raman spectroelectrochemistry of poly(N-methylaniline) (PNMA) layer deposited at a gold electrode was performed. Raman spectra were excited by four different laser wavelengths: UV line at 325 nm, a blue line at 442 nm, a red line at 633 nm, and a NIR line at 785 nm in solutions of different pH ranging from 1 to 9, and at different electrode potentials ranging from-0.5 V to 0.8 V. UV excitation reveals features characteristic for the reduced form of PNMA, even within the electrochemical potential range where oxidized forms of this polymer prevail. At a blue laser excitation, again, features of the reduced form are revealed, along with indications on the appearance of some kind of intermediate redox state within a definite potential window. Both red and NIR laser line excitations result in rich Raman features, disclosing all major redox forms as well as their interconversions by changing of electrode potential. The presence of polaronic form of PNMA even in pH-neutral and alkaline solutions has been disclosed. A detailed analysis of Raman vibrational bands is presented for different excitation wavelengths, different electrode potentials, and different solution acidities.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The selective quantitation of Cr(VI) was developed through colorimetric detection using starch-stabilized silver nanoparticles (starch-AgNPs). The detection of Cr(VI) was based on oxidative degradation of starchAgNPs as the reduction of UV-Vis signal and the distinctive color change from yellow to colorless of starch-AgNPs were observed. To achieve the highest sensitivity by this method, pH 3, and only 1 min were required for the determination of Cr(VI). For analytical performances, two linear ranges of 0- 6 mM and 10-80 mM with limit of detection of 0.93 mM (48 mg/L) and 11.57 mM (0.60 mg/L) were obtained, respectively. The developed colorimetric method was combined with inductively coupled plasma optical emission spectroscopy (ICP-OES) for the speciation analysis of chromium. The concentration of Cr(III) was calculated by subtraction of Cr(VI) from the total chromium concentration determined by ICP-OES. A satisfactory accuracy and precision based on the AOAC guidelines also proved that this simple and rapid sensor was successfully applied for speciation of chromium in real water samples.(c) 2022 Elsevier B.V. All rights reserved.
NSTL
Elsevier