查看更多>>摘要：UV spectrophotometry is a rapid and robust technique in resolving several challenging pharmaceutical combinations. Several mathematical treatments are available for the resolution of complex multicomponent UV spectra as; wavelet transformation, derivatization, and deconvolution-curve fitting models. Fourier self deconvolution (FSD) is a mathematical computational methodology for resolving interfering signals in many disciplines and applications. In the current work, we describe a modified FSD based methodology in resolving different binary pharmaceutical mixtures, which overcome the complexity of applying the traditional deconvolution-curve fitting technique on UV spectroscopic spectral data. The current approach differs from the conventional FSD by using the individual spectra of each component as a probing tool to avoid artifacts or errors on the deconvoluted spectra for accuracy of determinations. The utilized approach managed to resolve the binary mixtures of telmisartan/hydrochlorothiazide and ramipril/hydrochlorothiazide in their pharmaceutical dosage forms. The advantage of the current methodology over the traditional deconvolution-curve fitting is the simplicity of application, less time consuming, no need for sophisticated software, and higher sensitivity as revealed by the limit of detection (LOD). The linear ranges for telmisartan, ramipril, and hydrochlorothiazide were 1-25 mg/ml, 5-35 mg/ml, and 1-10 mg/ml, respectively, and the LOD values were in the ranges of 0.067-0.747 mg/ml. The developed FSD approach was validated as per the ICH recommendations regarding the accuracy, precision, linearity, selectivity, and limits of detection and quantitation. The recoveries obtained from the proposed approach were statistically compared with the corresponding reported methods and found no statistical difference between the obtained results. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this paper, we have applied the symmetry adapted one-dimensional framework of the U(2) Lie algebras to estimate the vibrational frequencies of tetrachloro-, tetrafluoro-, and mono-silanes in the gas phase having the spectroscopic interest of terrestrial volcanic plumes and other planetary atmospheres. A vibrational Hamiltonian that preserves the T-d point group symmetry of each of these silane molecules is devised using ten interacting Morse oscillator bound state spectra. The calculated vibron numbers and locality parameters indicate that the vibrational motion is highly anharmonic in SiH4 (nearest to local mode), moderately anharmonic in SiF4 (mixed mode) and the least anharmonic in SiCl4 (near to local mode). RMS deviations of the derived vibrational frequencies [0.41 cm(-1) (SiH4), 0.83 cm(-1) (SiCl4), and 0.63 cm(-1) (SiF4)], with reference to their experimental counterparts, assert that the U(2) Lie algebraic Hamiltonian is successful in deriving all the fundamental vibrations, their higher overtones and combination bands up to the fifth excitation, of each of the three silane molecules at the sub-cm(-1) level of accuracy, possibly at a much lower computational cost as compared to other theoretical methods. (C) 2021 Elsevier B.V. All rights reserved.
Klestova, Z. S.Voronina, A. K.Yushchenko, A. YuVatlitsova, O. S....
7页
查看更多>>摘要：Authors performed investigation on "antigen-antibody" interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 - 11 times). An impact of functionalization of sensor's sensitive element surface, as well as acidity of buffer solution on the activity of antigen-antibody interaction was studied here. The difference between sensor's responses to specific and non-specific interactions increased two-fold from 200 to 432 ang sec due to this treatment. When changing the acidity of analyzed solution from pH 7.3 to pH 6.8, the corresponding difference between sensor's responses increased by 6.3 times from 194 up to 1235 ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR. (c) 2021 Elsevier B.V. All rights reserved.
Dizman, H. MiracKazancioglu, Elif OzcelikShigemune, TakuyaTakahara, Shigeru...
7页
查看更多>>摘要：This study aimed for the development of a cost effective and efficient method for L-cysteine detection, without employing expensive instrumentation within a short analysis time. The proposed method has been involved in the photochemical preparation of gold nanoparticles and gold nanoparticles on graphene oxide nanostructures. The gold nanoparticles and gold nanoparticles on graphene oxide acted as simple and sensitive nano-sensors for L-cysteine, due to the molecular structure of the L-cysteine presented -NH2 and -SH, which is very attractive for coordination to gold nanoparticles and crosslink gold nanoparticles causing aggregation and color change. By using the gold nanoparticles on graphene oxide as a probe, the colorimetric detection of L-cysteine in a nanomolar order concentration was demonstrated. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Lysosome is one of the important organelles in intracellular transport. It plays a significant role in the physiological process. The lysosomal microenvironment affects the functions of lysosome. When the original acidic environment of lysozyme is destroyed or the fluid viscosity increases gradually, various diseases are easily induced. However, most fluorescent probes can only locate in cells. The fewer probes of subcellular organelles were found and their functions are often single. So, it is of great importance to design multifunctional fluorescent probes with the capable of localizing in lysosome. In this study, a novel lysosome probe, 4-(4-Pyren-1-yl-but-3-enyl)-morpholine (PIM), was synthesized using pyrene as a fluorescent group and morpholine as a target group. The introduction of morpholine group made PIM localize in lysosome with high selectivity. The fluorescence will be enhanced with the increased viscosity because of restricting the rotation of C-C bond and C=N in PIM, and the detecting linear range is from 4.05 cP to 393.48 cP, which qualified the requirement of the viscosity monitoring in body. Meanwhile, the fluorescence intensity of PIM declines with the decrease of pH because the Schiff base of PIM is hydrolyzed, which was affirmed by H-1 NMR, LC-MS and fluorescence spectra. Moreover, cell imaging and MTT experiments confirmed that PIM as a novel bifunctional probe can be used to detect pH and endogenous viscosity in lysosome. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：A novel fluorescent probe (DSD) was reasonably designed and synthesized with dansyl-labeled dipeptide (Dan-Ser-Asp-NH2). DSD featured remarkably large Stokes shift (230 nm) and perfect water solubility, and exhibited high selectivity and rapid recognition toward Cu2+ via fluorescence quenching. The detection limit of DSD for Cu2+ was 2.4 nM, indicated that DSD has excellent sensitivity. In addition, the stoichiometry between DSD and Cu2+ were detected as 1:1 by fluorescence titration, Job's plot and ESI-HRMS data. As designed, DSD-Cu2+ system was able to sequentially detect CN according to the displacement approach with fluorescence "off-on" response, and the detection limit for CN was calculated to be 41.9 nM. Specifically, the response time of DSD with Cu2+ and CN was less than 40 s, which rendered it suitable for real time detection in actual water samples. In addition, with the alternate addition of Cu2+ and CN , the reversible cycles could be repeated for at least 10 times, indicated that DSD was a promising reversibility probe. DSD showed low toxicity and good biocompatibility, and was successfully applied to detect Cu2+ and CN in living cells. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：The conversion of p-aminothiophenol (PATP) or p-nitrothiophenol (PNTP) to p,p'-dimercaptoazobenzene (DMAB) has been used as model reactions to study plasmon-catalyzed reaction on nanoparticles. Herein, we report the conversion of PNTP to DMAB which is triggered by SO32- ions on gold nanoparticles (AuNPs) for the first time. With the addition of SO32-, the Raman peaks at 1139, 1392, 1437 cm(-1) appears, which indicates the formation of DMAB. The experiment results suggested that the synergistic effect of AuNPs and SO32- promoted the conversion of PNTP to DMAB. Besides, the proposed catalysis system is high selectivity to SO32- ions, which provides a new detection route to SO32- ions in the future. More importantly, the possible reaction mechanism has been put forward which is helpful to understand the surface plasmon-assisted catalytic reduction of PNTP on the surface of SERS substrate. (C) 2021 Elsevier B.V. All rights reserved.
Gassoumi, B.Echabaane, M.Ben Mohamed, F. E.Nouar, L....
13页
查看更多>>摘要：In this work, the structures, quantum chemical descriptors, morphologic characterization of the azomethoxy-calix[4]arene were investigated. The analyses and interpretation of the theoretical and the experimental IR spectroscopy results for the corresponding compounds was performed. The complexation of the azo-methoxy-calix[4]arene with Zn2+, Hg2+, Cu2+, Co2+, Ni2+, Pb2+ and Cd2+ metal cations has been calculated by the dispersion corrected density functional theory (DFT-D3). The values of the interaction energies show that the specific molecule is more selective to the Cu2+ cation. The study of the reactivity parameters confirms that the azo-methoxy-calix[4]arene molecule is more reactive and sensitive to the Cu2+ cation than that Co2+ and Cd2+. In addition, the investigation of the electrophilic and nucleophilic sites has been studied by the molecular electrostatic potential (MEP) analysis. The Hirshfeld surface (HS) analysis of the azo-methoxy-calix[4]arene-Cu2+ interaction have been used to understand the Cu...hydrogen-bond donors formed between the cation and the specific compound. The Quantum Theory of Atoms in Molecules (QTAIM) via Non covalent Interaction (NCI) analysis was carried out to demonstrate the nature, the type and the strength of the interaction formed between the Cu2+ cation and the two symmetrical ligands and the cavity. Finally, the chemical sensor properties based on the Si/SiO2/Si3N4/Azo-methoxy-calix[4]arene for detection of Cu2+ cation were studied. Sensing performances are determined with a linear range from 10(-5.2) to 10(-2.2) M. The Si/SiO2/Si3N4/azo-methoxy-calix[4]arene structure is a promoter to have a good performance sensor. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Simultaneous saccharification and fermentation (SSF) of cassava is one of the key steps in the production of fuel ethanol. In order to improve the monitoring efficiency of the ethanol production process and the product yield, this study puts forward a new idea for monitoring of the cassava SSF process based on the molecular spectroscopy fusion (MSF) technique. Savisky-Golay (SG) combined with standard normal variable (SNV) was used to preprocess the obtained Raman spectra and near-infrared (NIR) spectra. Competitive adaptive reweighted sampling (CARS) was used to optimize the characteristic wavelengths of the preprocessed Raman spectra and the NIR spectra, and the optimized features were fused in the feature layer. The support vector machine (SVM) model of the process parameters during the cassava SSF based on the MSF features was established. The experimental results showed that compared with the best CARS-SVM model based on the single-molecule spectral features, the performance of the best CARS-SVM model based on fusion features has been significantly improved. For detection of the glucose content, the RMSEP, R2P and RPD of the best CARS-SVM model were 5.398, 0.957 and 4.922, respectively. For detection of the ethanol content, the RMSEP, R2P and RPD of the best CARS-SVM model were 4.394, 0.977 and 6.758, respectively. The obtained results reveal that the combination of MSF technique and appropriate chemometric methods can achieve high-precision quantitative detection of the process parameters during the cassava SSF. This study can provide technical basis and experimental reference for the development of portable spectrometer equipment for process monitoring of the cassava SSF. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Copper ion (Cu2+) is an essential part of the living organisms. Cu2+ ions play a vital role in many biotic processes. An abnormal amount of Cu2+ ions may result in serious diseases. Herein, a novel "fluorescent ON" probe NC-Cu to trace minute levels of Cu2+ ions in presence of various biological active species has been developed. Lysosomal cells targeting group (Morpholine) was added to the probe. The spectral properties of probe NC-Cu were recorded in HEPES buffer (0.01 M, pH = 7.4, comprising 50% CH3CN, lambda(ex) = 430-nm, slit: 5 nm). The synthesized probe NC-Cu work based on copper promoted catalytic hydrolysis of hydrazone and shows remarkable fluorescence enhancement. The reaction of the probe with Cu2+ ions was completed within 20 min. An excellent linear relationship (R-2 = 0.9952) was found and the limit of detection (LOD, according to the 3 sigma/slope) for Cu2+ ions was calculated to be 5.8 mu M. Furthermore, NC-Cu was effectively functional in the living cells (KYSE30 cells) to trace Cu2+ ions. (C) 2021 Elsevier B.V. All rights reserved.
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