2-(2-Hydroxyphenyl)benzothiazole (HBT) derivatives with donor-π-acceptor (D-π-A) structure have received extensive attention as a class of excited state intramolecular proton transfer (ESIPT) compounds in the fields of biochemistry and photochemistry. The effects of electron-donors (triphenylamine and anthracenyl), the position of substituents and solvent polarity on the fluorescence properties and ESIPT mechanisms of HBT derivatives were investigated through time-dependent density functional theory (TDDFT) calculations. Potential energy curves (PECs) and frontier molecular orbitals (FMOs) reveal that the introduction of the triphenylamine group on the benzene ring enhances intramolecular HB, thereby benefiting the ESIPT process.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
The excited (S) state charge distribution characteristics and fluorescence mechanism of fluorescence probes benzyl (6-cyano-2-naphthoyl)-L-valinate (NPI) and benzyl (6-amino-2-naphthoyl)-L-valinate (NPA) have been discussed using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Further analysis by constructing a torsional potential energy curve (PEC) shows that a well-defined minimum energy conformation is observed when the C-C single bond between the valine benzyl ester and naphthalene ring in NPI rotates. For NPA, the most stable conformation is the naphthalene ring conformation with dihedral angle NCCC of -30.
View Article and Find Full Text PDFOur main focus is to explore the atomic electronegativity-dependent photoinduced behavior of styryl derivatives (HBO, HBS, and HBSe). The results of structural parameter calculation by the DFT method show that the intramolecular hydrogen bonds of normal and tautomer form are strengthened and weakened, respectively, in an excited state (S), which is conducive to the excited intramolecular proton transfer (ESIPT) process. The enhancement of excited hydrogen bond is beneficial to the ESIPT process from the aspects of infrared vibration frequency (IR), Mulliken's charge analysis, and density gradient reduction (RDG).
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
November 2022
Background: Yin Huo Tang (YHT), a traditional Chinese herbal formula, is effectively used for the clinical treatment of menopause-like symptoms in China. This study aimed to investigate its efficacy on menopause-like symptoms in mice using behavioral tests and histopathological assessment, and to determine its possible mechanism of action based on network pharmacology.
Methods: Liquid chromatography-mass spectrometry (LC-MS) technology was used to identify the potential active ingredients of YHT.
The present study investigated the effects of different extraction methods including water-water bath (W-WB), ethanol-water bath (E-WB), deep eutectic solvent (DES) combined with ultrasound-assisted extraction (DES-UAE), microwave-assisted extraction (DES-MAE), and enzyme-assisted extraction (DES-EAE) on flavonoids (total flavonoid content, flavonoid composition, and stability) in jujube. The highest total flavonoid content of 8.03 mg/g was obtained by the DES-MAE extraction.
View Article and Find Full Text PDFSichuan Da Xue Xue Bao Yi Xue Ban
March 2021
Objective: To assess the clinical effectiveness of boundary recognition of upper abdomen organs on CT images based on neural network model and the combination of different slices.
Methods: A total of 2 000 patients who underwent upper abdomen enhanced CT scans from March 2018 to March 2019 were included in the study. The quality of the CT images met the requirements for clinical diagnosis.
Sichuan Da Xue Xue Bao Yi Xue Ban
July 2019
Objective: To determine the myocardial texture features of cardiac magnetic resonance (CMR) in healthy adult Han populations.
Methods: 59 healthy Han volunteers were recruited for this study from May 2016 to November 2017. CMR examinations were performed on the participants with a 3.
Malignant hyperthermia is a pharmacogenetic disorder, which is an uncommon but frequently fatal intricacy of inhalation anesthesia in man. It causes a quick rise in body temperature to highly irreversible levels, which causes death in around three of four cases. The trigger anesthetics cause an anomalous, continued ascent in myoplasmic calcium levels.
View Article and Find Full Text PDFWe propose that aromatic nitro and amine compounds undergo photochemical reductive and oxidative coupling, respectively, to specifically produce azobenzene derivatives which exhibit characteristic Raman signals related to the azo group. A photoinduced charge transfer model is presented to explain the transformations observed in para-substituted ArNO(2) and ArNH(2) on nanostructured silver due to the surface plasmon resonance effect. Theoretical calculations show that the initial reaction takes place through excitation of an electron from the filled level of silver to the lowest unoccupied molecular orbital (LUMO) of an adsorbed ArNO(2) molecule, and from the highest occupied molecular orbital (HOMO) of an adsorbed ArNH(2) molecule to the unoccupied level of silver, during irradiation with visible light.
View Article and Find Full Text PDFWhen p-aminothiophenol (PATP) is used as a probe molecule and adsorbs on silver and gold nanogaps, a significant change of relative SERS intensities can be observed. Our DFT calculations show that surface photocatalytic coupling reactions yield a new surface species of p,p'-dimercaptoazobenzene (DMAB) causing the significant change in the SERS spectra.
View Article and Find Full Text PDFBinding interactions and Raman spectra of water in hydrogen-bonded anionic complexes have been studied by using the hybrid density functional theory method (B3LYP) and ab initio (MP2) method. In order to explore the influence of hydrogen bond interactions and the anionic effect on the Raman intensities of water, model complexes, such as the negatively charged water clusters ((H2O)n-, n = 2 and 3), the water..
View Article and Find Full Text PDF