查看更多>>摘要：Based on the previous research, we found that the magnetic nanocomposite Fe3O4/rGO (reduced graphene oxide) has a good drug loading effect. Therefore, in this paper, we studied the positive role of Fe3O4/rGO as a drug carrier in the interaction between resveratrol (RES) and calf-thymus DNA (ctDNA). The fluorescence experiment is used to evaluate by the Stern-Volmer equation, the quenching constant of RES ct-DNA system with and without Fe3O4/rGO decreases with the increasing temperature. It was found the quenching mode of RES ct-DNA and Fe3O4/rGO RES ct-DNA systems were all static quenching, but the binding constant of RES-ct-DNA increased from 4.14 +/- 0.21 x 10(4) L mol(-1) to 10.12 +/- 0.02 x 10(4) L mol(-1). It was found that Fe3O4/rGO formed a ternary complex with RES and ct-DNA by ultraviolet spectrum (UV-vis), resonance light scattering experiments (RLS) and scanning electron microscope (SEM). Meanwhile, Fourier transform infrared (FT-IR) and circular dichroism (CD) experiments show that Fe3O4/rGO and Fe3O4/rGO loaded with RES have effect on the secondary structure of ct-DNA and change the conformation of ct-DNA. On the cellular level, the comet assay shows that Fe3O4/rGO and Fe3O4/rGO RES could not cause DNA strand break to the mouse hepatocytes after 24 co incubation. These results confirm that Fe3O4/rGO nanocomposites have good application potential, which can be used as a good drug carrier in a wide range of therapeutic methods. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：To our knowledge, there is little research done in using vibrational MID-IR molecular spectroscopyattenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) for ruminant system study. The objective of this study was to use ATR-FTIR as a fast analytical tool to reveal association between protein molecular structure in faba and metabolizable protein supply and nutrient delivery, and to explore the relationship between protein molecular structure in original and ruminal degraded residue and in situ rumen protein degradation and protein metabolism characteristics of faba bean samples (whole crop, stem, leaf, whole pods, and faba silage). The experiment for ruminant nutrition research was RCBD. Fourier transform Infrared (FTIR) spectra of faba samples before and after 12 and 24 h rumen incubations were collected with JASCO FT/IR-4200 with ATR at mid-IR range (ca. 4000-700 cm-1) with 128 scans and at 4 cm-1 resolution. The univariate molecular spectral analysis was carried using OMNIC software. Protein related spectral parameters before and after rumen degradation included amide region (ca. 1730-1480 cm-1), amide I region (ca. 1713-1558 cm-1) and amide II region (ca. 1558- 1485 cm-1). Within amide I region, a-helix (ca. 1644 cm-1) and b-sheet (ca. 1630 cm-1) were studied. The results showed that ATR-FTIR protein molecular spectral features were significantly different before and after rumen incubation. Protein availability and digestion characteristic are mainly determined by original ATR-FTIR spectral profiles. Total truly digestible protein value (DVE) of faba partitions could be predicted with this equation: DVE (g/kg DM) = 1207.7 HAII12 + 228.7 alpha_beta24 - 310.8 (with R-square = 0.94, RSD = 8.06, model P < 0.001). The study shows that vibrational MID-IR molecular spectroscopy (ATR-FTIR) show a high potential to be a fast analytical tool to predict nutrient delivery. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Rapid and quantitative detection of bacterial antibiotic resistance is of great significance for the prevention and treatment of infections and understanding drug-resistant mechanism. In this study, label-free surface-enhanced Raman spectroscopy (SERS) technology was applied to dynamically explore oxacillin/cefazolin-derived resistance in Staphylococcus aureus using a portable Raman spectrometer. The results showed that S. aureus rapidly responded to oxacillin/cefazolin stimulation and gradually developed different degrees of drug resistance during the 21 days of exposure. The molecular changes that accumulated in the drug-resistant strains were sensitively recorded by SERS in a whole-cell manner. Principal components-linear discriminant analysis correctly distinguished various degrees of drug resistant strains. The typical Raman peak intensities of I-734/I-867 showed a negative and non-linear correlation with the minimum inhibitory concentration (MIC). The correlation coefficient reached above 0.9. The target sites of oxacillin/cefazolin on S. aureus clearly reflected on SERS profiles. The results collected by SERS were further verified by other biological methods including the antibiotic susceptibility test, MIC determination, and PCR results. This study indicates that SERS technology provides a rapid and flexible alternative to current drug susceptibility testing, laying a foundation for qualitative and quantitative evaluation of drug resistance in clinical detection. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A novel oxene based unusual sensory receptor (HyMa) has been synthesized via. Knoevenagel condensation triggered carbon-heteroatom (oxygen) intramolecular bond formation reaction at room temperature for discriminative detection of multi-analytes like HSO4-,CN-& nbsp;& F(-& nbsp;)by spectro-photometric alterations with profound selectivity with the detection limit of 38 ppb, 18 ppb & 94 ppb respectively. Examination of the sensing mechanism was exhaustively investigated through several spectroscopic & nbsp;means like H-1 NMR, FT-IR, absorption and fluorescence spectra etc. In addition, quantum mechanical calculations like DFT and Loewdin spin population analyses also validated the rationality of the host-A novel oxene based unusual sensory receptor (HyMa) has been synthesized via. Knoevenagel condensation triggered carbon-heteroatom (oxygen) intramolecular bond formation reaction at room temperature for discriminative detection of multi-analytes like HSO4-, CN- & F- by spectro-photometric alterations with profound selectivity with the detection limit of 38 ppb, 18 ppb & 94 ppb respectively. Examination of the sensing mechanism was exhaustively investigated through several spectroscopic interaction. Apart from these, the reversible spectroscopic responses of HyMa towards F- and Al3+ can imitate several complex logic functions that in turn help in preparing molecular keypad lock. This molecular keypad lock has the potential to protect the confidential information at the molecular scale. Additionally, the MTT assay of HyMa showed low cytotoxicity and membrane permeability indicating its attractive capability for bio-imaging towards triple negative breast cancer. HyMa-coated test strips could also be employed towards on-site detection of these deadly contaminants via "Dip Stick " approach without help of any instrumentation. In addition, HyMa has also been exploited for quantitative determination of HSO4- from various real water samples. In a nutshell, detection of lethal contaminants like CN-, F- & HSO4- at ppb level with in vitro live cell imaging has been explored with proper photophysical characterisation and theoretical calculations with real field applications. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Redox balance is a necessary guarantee to maintain the normal physiological activities of organisms. Cysteine (Cys), a critical biological thiol, has the effect of maintaining redox balance in the body. The concentration of intracellular Cys is abnormal under redox imbalance, thereby resulting in multiple diseases. Additionally, studies have revealed that Cu2+ can stimulate the body to produce excess reactive oxygen species (ROS, similar to H2O2), and the generated ROS will consume reducing substances (such as Cys) in the body, leading to redox imbalance. Thus, finding a simple and effective method to monitor Cys under redox imbalance is pressing. Here, a turn on probe (DDNO) was proposed by connecting SBD-Cl to a red dye (HDM). The probe can specifically recognize Cys with rapid response (180 s) and low detection limit (0.61 lM) through substitution-rearrangement reaction between sulfhydryl and chlorine atom. Bioimaging experiments indicated that the probe has good biocompatibility and cell membrane permeability, which can be applied to monitor the fluctuation of Cys levels in live cells and zebrafish under the redox imbalance induced by Cu2+ or H2O2. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
Zandbaaf, ShimaKhorrami, Mohammad Reza KhanmohammadiAfshar, Majid Ghahraman
9页
查看更多>>摘要：The current study proposes a novel analytical method for calculating the breakdown voltage (BV) of transformer oil samples considered as a significant method to assess the safe operation of power industry. Transformer oil samples can be analyzed using the Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with multivariate calibration methods. The partial least squares regression (PLSR) back propagation-artificial neural network (BP-ANN) methods and a genetic algorithm (GA) for variable selection are used to predict and assess breakdown voltage in transformer oil samples from various Iranian transformer oils. As a result, the root mean square error (RMSE) and correlation coefficient for the training and test sets of oil samples are also calculated. In the GA-PLS-R method, the squared correlation coefficient (R(2)pred) and root mean square prediction error (RMSEP) are 0.9437 and 2.6835, respectively. GA-BP-ANN, on the other hand, had a lower RMSEP value (0.2874) and a higher R(2)pred function (0.9891). Considering the complexity of transformer oil samples, the performance of GA-BP-ANN has resulted in an efficient approach for predicting breakdown voltage; consequently, it can be effectively used as a new method for quantitative breakdown voltage analysis of samples to evaluate the health of transformer oil. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Soil organic matter (SOM) is a key index for evaluating soil fertility and plays a vital role in the terrestrial carbon cycle. Visible and near-infrared (Vis-NIR) spectroscopy is an effective method for determining soil properties and is often used to predict SOM content. However, the key prerequisite for effective prediction of SOM content by Vis-NIR spectroscopy lies in the selection of appropriate preprocessing methods and effective data mining techniques. Therefore, in this study, six commonly used spectral preprocessing methods and effective characteristic band selection methods were selected to process the spectrum to predict SOM content. This study aims to determine a stable spectral preprocessing method and explore the predictive performance of different characteristic band selection methods. The results showed that: (i) The first derivative (FD) is the most stable spectral preprocessing method that can effectively improve the spectral characteristic information and the prediction effect of the model. (ii) The prediction effect of SOM content based on characteristic band selection methods is generally better than the full-spectra data. (iii) The precision of FD preprocessing spectrum combined with successive projections algorithm (SPA) in the partial least square regression prediction model of SOM content is the best. (iv) Although the prediction effect of the model based on the optimal band combination algorithm is slightly lower than that of SPA, it shows stable prediction performance, which provides a feasible method for SOM content prediction. In summary, the characteristic band selection method combined with FD can significantly improve the prediction accuracy of SOM content.(c) 2022 Published by Elsevier B.V.
查看更多>>摘要：In situ investigation of mineral behavior in water medium at simultaneously high P-T parameters can be applied to modelling of mineral transformation processes in lithospheric plates. The behavior of zeolites wairakite and phillipsite under the P-T conditions of "cold" slab subduction, corresponding to the start of oceanic plate diving or ocean floor near geothermal sources, was studied by in situ Raman spectroscopy. During compression in water medium, phillipsite initial phase is stable up to T = 350 degrees C, P = 1.7 GPa and with further increase of P-T parameters, phillipsite undergoes amorphization and partially dissolves in water. Wairakite compressed in water medium has a polymorphic transformation at T approximate to 300 degrees C and P approximate to 0.4 GPa. At 300-450 degrees C and P = 1 GPa the Raman spectrum almost disappears due to the amorphization of wairakite. Zeolite wairakite partially dissolves, and other zeolite phillipsite grows out of the fluid at T = 450 degrees C and P = 1 GPa. This transformation indicates the higher stability of phillipsite in comparison to wairakite. The in situ observed high P-T stability of phillipsite, which does not transform to other zeolites, and its formation from wairakite may indicate phi possible widespread distribution of this zeolite in marine sediments. By using the plane-wave pseudo-potential method, ab initio DFT calculations of Raman and FTIR spectra of wairakite were carried out. Comparing theoretical and experimental spectra, interpretation of the vibrational spectra of both zeolites was suggested. (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：Nanosensors represent a class of emerging promising nanotools that can be used for the rapid, sensitive and specific detection of relevant molecules such as biomarkers of cancer or other diseases. The sensing platforms that rely on the exceptional physical properties of colloidal gold nanoparticles have gained a special attraction and various architectural designs were proposed with the aim of rapid and real-time detection, identification and monitoring of the capturing events. Moreover, biomarker sensing in liquid samples allows a more facile implementation of the nanosensors by circumventing the need for invasive practices such as biopsies, in favor of non-invasive investigations with potential for use as point-of-care assays. Herein, we propose a sandwich-type surface enhanced Raman scattering (SERS) immunonanosensor which is aimed for detecting and quantifying Carcinoembryonic antigen-related cell adhesion molecule 5 (CEA-CAM5), a protein involved in intercellular adhesion and signaling pathways that acts as a tumor marker in several types of cancer. For constructing the proposed system, colloidal gold nano spheres (GNS) and gold nano-urchins (GNU) were chemically synthesized, labeled with SERS active molecules, conjugated with polymers, functionalized with antibodies as capturing substrates and tested in two different sensing configurations: pairs of GNUs-GNUs and GNUs-GNSs. When the target antigen is present in the analyte solution, nanoparticle bridging occurs and a subsequent amplification of the characteristic Raman signal of the label molecule appears due to the formation of hot-spots in interparticle gaps. The capability of observing small analyte concentrations in liquid samples with an easy-to handle portable Raman device makes the proposed system feasible for rapid, non-invasive and costeffective clinical or laboratory use.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：This article reports a facile strategy to detect hexavalent chromium (Cr (VI)) using a naturally formed mineral (kyanite) based fluorometric sensor. Nitrogenous carbon dots have been incorporated into natural kyanite (KYCD) nanoparticles causing a stable bright blue fluorescence compared to its pristine counterpart. This sensing probe structurally stabilizes and resists the agglomeration of carbon dots, thus retaining fluorescence quality for a longer period. The promising bright blue fluorescence has been utilized further to detect Cr (VI) in wastewater and living cells. Ease of synthesis, low cost, and stability of the system offers the benefit for large-scale production, which is convenient for industrial production the sensing probe. The sensor shows high selectivity and sensitivity (LOD and LOQ of 0.11 mM and 0.36 mM respectively in case of linear fitting, whereas 0.26 mM and 0.88 mM respectively for full range plot) towards hexavalent chromium in presence of other interfering elements. A detailed study of photoinduced electron transfer (PET) mediated rapid 'turn off' sensing mechanism was carried out using Time-Dependent Density functional (TDDFT) calculations. The sensing efficacy of the probe remains unaltered under a wide range of pH and can be effective in various water types. Onsite sampling and probing of Cr (VI) in tannery wastewater has been performed to validate its real-life efficiency that yields excellent results. The sensor can effectively detect chromium at a cellular level (HeLa cells) in a similar way as the bright blue fluorescence diminishes in presence of the quenching ion. Experimental in vitro studies along with theoretical docking analysis has been conducted to substantiate such issues and a higher possibility of fluorophore binding was found for Isoleucine (2.9 A), Serine (2.96 A), and Glycine (3.16 A). This biocompatible sensor rapidly senses hexavalent chromium in living cells, which makes this efficient probe a true heavy metal-induced carcinogen sensor.(c) 2022 Elsevier B.V. All rights reserved.
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