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PubMed Journal Database | Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy RSS

13:02 EDT 25th March 2019 | BioPortfolio

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Showing PubMed Articles 1–25 of 1,900+ from Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy

Spectral-fluorescent study of the interaction of polymethine dye probes with biological surfactants - bile salts.

Spectral-fluorescent properties of polymethine dye probes anionic 3,3'-di(sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine-betaine (DEC) and cationic 3,3',9-trimethylthiacarbocyanine iodide (Cyan 2) in the presence of biological surfactants, bile salts sodium cholate (NaC), sodium deoxycholate (NaDC) and sodium taurocholate (NaTC), as well as sodium dodecyl sulfate (SDS), have been studied in a wide range of surfactant concentrations. When a surfactant is introduced into a solution of DEC, changes of ...

Rapid and quantitative detection of trace Sudan black B in dyed black rice by surface-enhanced Raman spectroscopy (SERS).

The use of Sudan black B as coloring agent in foods is forbidden for its toxicology effect on human organs. This work proposes an efficient and sensitive method for food security inspection targeting Sudan black B. Surface-enhanced Raman spectroscopy (SERS) is applied to the analysis of trace Sudan black B. It could be detected at concentrations as low as 0.05 mg/L in standard solutions and 0.1 mg/kg in black rice extracts with the SERS method for measurement. The linear relationship between the intensi...

Novel polysiloxane-based rhodamine B fluorescent probe for selectively detection of Al and its application in living-cell and zebrafish imaging.

Polysiloxanes have excellent stability and biological relevance and are suitable for biological research. However, there were few polysiloxane-based fluorescent probes for bioimaging. This report successfully designed a new polysiloxane-based polymer fluorescent probe (RB-1) for the first time as a "turn-on" fluorescent probe response to Al ion with highly sensitive and selectivity. Importantly, this probe could also apply both in cell and zebrafish imaging, indicating the huge application development prosp...

Multi-wavelength spectrophotometric measurement of persulfates using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as indicator.

A spectrophotometric method using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as the indicator was proposed for measuring persulfates, i.e., peroxymonosulfate (PMS) and peroxydisulfate (PDS). This method was based on the direct oxidation of the colorless ABTS by PMS/PDS to generate the green-colored ABTS at neutral pH and room temperature. The generated ABTS had four different characteristic absorption peaks at 820 nm, 732 nm, 650 nm and 415 nm. The absorption values at these wavelengt...

Theoretical and experimental study on the effects of pH and surfactant on the internal charge transfer process in distyrylnaphthalene-based conjugated oligoelectrolytes.

In this study we have investigated the effects of pH and surfactant on the internal charge transfer (ICT) process in the DSNN derivative, DSNN-NMe (4,4'-bis(4'-(N,N-bis(6″-(N,N,N-trimethylammonium)hexyl)amino)-styryl) naphthalene tetraiodide) with the aim to show that environmentally-induced changes in the degree of ICT process determine the spectral response of the DSNN chromophore. Obtained results showed that DSNN chromophore exhibits evident changes in linear optical properties (absorption/emission wa...

Theoretical insights into UV-Vis absorption spectra of difluoroboron β-diketonates with an extended π system: An analysis based on DFT and TD-DFT calculations.

The UV-Vis absorption spectra of difluoroboron β-diketonates with aromatic substituents at the β-carbon are studied thoroughly using DFT and TD-DFT with the CAM-B3LYP functional. The complicated experimental spectra of these dyes can be correctly interpreted by considering their structural features. A closer look at the calculated data shows that the conformational flexibility of these compounds markedly influences their spectral shape. For the complexes with an extended π system, several conformers with...

Influence of chemical fixation process on primary mesenchymal stem cells evidenced by Raman spectroscopy.

In investigation of (patho)physiological processes, cells represent frequently used analyte as an exceptional source of information. However, spectroscopic analysis of live cells is still very seldom in clinics, as well as in research studies. Among others, the reasons are long acquisition time during which autolysis process is activated, necessity of specified technical equipment, and inability to perform analysis in a moment of sample preparation. Hence, an optimal method of preserving cells in the existi...

Theoretical investigation of the vibronic phosphorescence spectra and quantum yields for iridium(III) complexes with 2-(2,5,2',3',4',5',6'-heptafluoro-biphenyl-4-yl)-pyridine as the primary ligand.

Cyclometalated Ir(III) complexes are widely used as phosphorescent materials in organic light-emitting diodes. In this work, the vibrationally resolved phosphorescence spectra of an experimental reported and four novel designed Ir(III) complexes with 2-(2,5,2',3',4',5',6'-heptafluoro-biphenyl-4-yl)-pyridine (HFYP) as primary ligand are investigated by theoretical calculations. The ancillary ligands are 3-(pentafluorophenyl)-pyridin-2-yl-1,2,4-triazolate (exp3), 3-(trifluoromethyl)-pyridin-2-yl-1,2,4-triazol...

A facile SERS strategy for quantitative analysis of trace glucose coupling glucose oxidase and nanosilver catalytic oxidation of tetramethylbenzidine.

Highly stable, SERS active and catalytic nanosilver sol (AgNP) was synthesized under the exposure of light wave, using AgNO as precursor and sodium citrate as reducer. Under the conditions of pH 7.0 NaHPO-NaHPO buffer solution (PBS), the glucose can be catalyzed by glucose oxidase to produce HO specifically. Based on the nanocatalyst and SERS substrate of AgNP, HO can oxidize the 3,3',5,5'-tetramethylbenzidine (TMB) quickly to form a blue oxidation product (TMB) that induced the AgNPs aggregation, which e...

Simultaneous multi-gas detection between 3 and 4 μm based on a 2.5-m multipass cell and a tunable Fabry-Pérot filter detector.

We demonstrated a versatile and innovative gas sensing system based on a Fabry-Pérot (FP) filter detector, which operates in the spectral range from 3.1 to 4.4 μm (3226-2273 cm) with a spectral resolution of 20 nm. The developed sensor system can be used to record the entire spectrum by means of a one-time scan or, alternatively, to access selected spectral regions by using the tunable FP filter detector. A multipass cell with an effective path length of 2.5 m was implemented to improve the detect...

A nano sensor for sensitive and selective detection of Cu based on fluorescein: Cell imaging and drinking water analysis.

A fluorescein-based nano probe was designed and synthesized for ultra-sensitive detection of Cu in aqueous solution. The formation of fluorescent organic nanoparticles confirmed by using particle size analysis and scanning electron microscopy. UV-Vis. absorption and fluorescence spectroscopy displays excellent photophysical properties of prepared nanoparticles as compared to parent molecule i.e. N-(3',6'-dihydroxy-3-oxo-3,3a-dihydrospiro[isoindole-1,9'-xanthene]-2(7aH)-yl)-1-naphthamide (FNH) in acetone. A ...

Temperature dependence of Raman spectra and first principles study of NiMnO magnetic spinel oxide thin films. Application in efficient photocatalytic removal of RhB and MB dyes.

Magnetic spinel oxide NiMnO thin films were grown on glass substrates using the spray pyrolysis deposition technique at 350 °C. First, structural optimization, electronic structure and vibrational properties were obtained for NiMnO by density functional theory (DFT) with an all electron basis set and the hybrid functional B3LYP implemented in the CRYSTAL14 code. Our DFT results show good agreement with previous experimental and theoretical data. Second, Raman spectra of as-prepared thin films have been m...

Comparison of different fluorescence techniques in brandy classification by region of production.

Fluorescence spectrometry coupled with chemometrics was used to discriminate between 44 brandies originating from different countries. The kind of spectrum (emission, total luminescence and synchronous fluorescence), the geometry of sample illumination (front-face and right angle), and the sample type (bulk and diluted) were considered to compare the brandy classification. Firstly, the emission and synchronous fluorescence spectra (SFS) were processed by the principal component analysis (PCA) and the excita...

Physical mechanism on edge-dependent electrons transfer in graphene in mid infrared region.

In this paper, we report nanophotonic properties of single layer graphene with Zigzag and/or armchair edge in the region of Mid Infrared (Mid-IR). The photoinduced charge transfer of graphene can occur in electronic state transition of Mid-IR region, and then the transferred electrons can interact with the phonon of graphene at Mid-IR. The coupling excitation of photon and phonon (graphene plasmon) can results in photon-electron-phonon interactions, which can significantly enhance resonance Raman scattering...

Structural investigation of a 2:1 co-crystal between diflunisal and isonicotinamide based on terahertz and Raman spectroscopy.

In order to characterize molecular structure changes of drugs upon co-crystallization by means of spectroscopic techniques, vibrational spectra of solid-state diflunisal (DIF), isonicotinamide (ISO) and their 2:1 co-crystal have been investigated by using terahertz time-domain spectroscopy (THz-TDS) and Raman spectroscopy. A 2:1 DIF-ISO co-crystal between DIF and ISO has been synthesized by slow solution crystallization from ethanol. The experimental THz spectroscopy shows that the co-crystal has a few sign...

Spectroscopic probing of the refolding of an unfolded protein through the formation of mixed-micelles.

We report the unfolding of the globular protein, Bovine Serum Albumin (BSA) induced by anionic surfactant sodium dodecyl sulfate (SDS) and subsequently monitored the refolding of this denatured BSA using triblock copolymers F127 and P123 through the formation of mixed micelles. Our study exclusively represents the reversibility of this unfolding-refolding process using pluronic triblock copolymers F127/P123 as refolding agents. We confirm the recovery of its native state from its denatured state estimating ...

A novel peptide-based fluorescent chemosensor for Cd(II) ions and its applications in bioimaging.

Nowadays, it is of great significance to develop a novel fluorescent chemosensor for Cd(II) ions detection with cost-effective, rapid, facile and applicable to environment and biological milieus. Herein, we report a new peptide-based fluorescent chemosensor DSC (Dan-Ser-Cys-NH) based on dipeptide (Ser-Cys-NH) conjugated with dansyl group, which was synthesized using solid phase peptide synthesis (SPPS) technology. As designed, DSC exhibited fluorescent "turn-on" response for Cd in 100% aqueous solution over...

Theoretical insight on hybrid nanocomposites of graphene quantum dot and carbazole-carbazole dyes as an efficient sensitizer of DSSC.

The feasibility of the hybrid nanocomposites of the graphene quantum dot (GQD) and carbazole-carbazole dyes as the efficient sensitizer of dye-sensitized solar cells (DSSC) is investigated. By using the first principles density functional theory (DFT), we fully optimize the geometrical structures of GQD, the carbazole-carbazole dyes, and their hybrid nanocomposites. The harmonic frequency analysis is used to confirm the energy stability of the optimized structures. The optical absorptions of the structures ...

Exploring the behavior of gold nanostar@reduced graphene oxide composite in chemiluminescence: Application to highly sensitive detection of glutathione.

Gold nanostar@reduced graphene oxide (GNS@rGO) nanocomposite was used as a catalyst in a chemiluminescence (CL) reaction. Composites with different sizes of gold nanostars were prepared without any surfactant, and characterized by transmission electron microscopy, UV-visible, FT-IR and Raman spectroscopy. We showed that GNS@rGO can strongly enhance the intensity of luminol‑sodium periodate CL system and the larger the GNS size, the greater the enhancing effect. This effect results from the unique catalyti...

N-doped carbon dots under Xenon lamp irradiation: Fluorescence red-shift and its potential mechanism.

Despite extensive research on carbon dots (CDs), rare studies have been performed on the photostability of CDs. Here, the photostability of CDs synthesized with 3-aminobenzoic acid were systematically investigated under different pH conditions (5.0, 7.4 and 9.0). The results showed that under Xenon lamp irradiation, the fluorescence (FL) intensity of the CDs exhibited an increase first and then a decrease, with a gradual shift of the maximum emission wavelength to longer wavelength. Further investigation in...

Novel two-photon fluorescent probe with high fluorescence quantum yields for tracking lipid droplets in biological systems.

Lipid droplets (LDs) played an important role in storing neutral lipids process. In this work, we developed a series of fluorescent dyes PIE1-PIE4 with high fluorescence quantum yields based on a single phenanthrenequinone imidazole fluorophore core. Among these compounds, we introduced diethyl aniline group on the phenanthrenequinone imidazole core to provide the compound PIE1. It is firstly found that PIE1 could real-color image and track lipid droplets (LDs) in living cells. However, we modified nitrile,...

Synthesis of methionine methyl ester-modified coumarin as the fluorescent-colorimetric chemosensor for selective detection Cu with application in molecular logic gate.

A methionine methyl ester-modified coumarin derivative was designed and synthesized, which could discriminate Cu from other metal ions in HEPES buffer (10 mM, pH 7.4)/CHCN (40:60, V/V). The detection limit of WM toward Cu was 1.84 × 10 M, which was lower than the concentration of Cu in drinking water suggested by WHO and EPA. And the proposed coordination mode exhibiting the interaction between WM and Cu was studied by UV-Vis, fluorescence spectrum, ESI-MS and FT-IR. Based on the fluorescent reve...

A preliminary study on constructing a high-dimensional asynchronous spectrum to analyze bilinear data.

A novel approach to constructing high-dimensional asynchronous spectra (nD-Asyn) is proposed. Three theorems relevant to 1D slices of nD-Asyn are revealed. nD-Asyn is used to analyze bilinear data from mixtures containing multiple components obtained via hyphenated techniques. The spectral contribution of different components can be removed in a stepwise manner by increasing the dimensions of asynchronous spectra. As a result, the spectra of different components can be faithfully recovered even if the time-...

Spectrophotometric determination of phenol and chlorophenols by salting out assisted liquid-liquid extraction combined with dispersive liquid-liquid microextraction.

In this work, salting out liquid-liquid extraction (SALLE) combined with dispersive liquid-liquid microextraction (DLLME) was developed as a novel extraction method for extraction and preconcentration of phenol and chlorophenols (CPs) in environmental water samples. The analytes were derivatized with 4-aminoantipyrineand determined by spectrophotometry. Experimental parameters such as type and volume of the organic solvent, type and amount of salt, pH and vortex time were optimized. Under the optimum condit...

Effect of phenothiazine compounds on the secondary structure and fibrillogenesis of poly-l-lysine.

Phenothiazine molecules are effective and commonly used antipsychotic drugs, especially in the treatment of schizophrenia. However, they produce strong extrapyramidal side-effects manifested by drug-induced parkinsonism. Because Parkinson's disease as a neurodegenerative illness is associated with the formation of amyloid fibrils in neuronal cells, it is postulated that the development of phenothiazine-induced parkinsonism may be related to the phenothiazine-induced formation of fibrillar aggregates. The ef...


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