We report the results of the experimental and theoretical studies of the polarized IR crystalline spectra of 4-bromo-3,5-dimethylpyrazole (4Br35DMPz) and 3,4-dimethoxyphenylacetic acid (34DMPAA) as well as the spectra of their deuterium-bonded analogues. The results of model calculations of the temperature impact exerted on to the band shapes measured in the X-H- and X-D bond stretching vibration regions, performed on the basis of the "strong-coupling" model, are also shown. These studies confirm a direct relationship between the spectral properties in IR and the electronic structure of the associating molecules in the crystals. Two different competing exciton coupling mechanisms involving hydrogen bonds, the "tail-to-head" (TH) in 4Br35DMPz and the "side-to-side" coupling in 34DMPAA, were recognized. The molecular electronic structure determines the relative contribution of each individual vibrational exciton coupling mechanism in the spectra generation. It also strongly influences the temperature-induced evolution of the Davydov-splitting effects in the crystalline spectra. Dynamical co-operative interactions responsible for a non-random distribution of protons and deuterons in the crystal hydrogen bonds can also be identified in the investigated systems.
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http://dx.doi.org/10.1016/j.saa.2014.02.079 | DOI Listing |
Inorg Chem
January 2025
School of Materials Science and Engineering, China University of Petroleum, Qingdao 266580, PR China.
Mismatched electron and proton transport rates impede the manifestation of effective performance of the electrocatalytic oxygen evolution reaction (OER), thereby limiting its industrial applications. Inspired by the natural protein cluster in PS-II, different organic-inorganic hybrid electrocatalysts were synthesized via a hydrothermal method. -Toluidine (PT), benzoic acid (BA), and -aminobenzoic acid (PABA) were successfully intercalated into NiFe-LDH.
View Article and Find Full Text PDFCell Biol Int
January 2025
Laboratory of Leishmaniasis, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Leishmaniases affect millions of people around the world, caused by Leishmania parasites. Leishmania are transmitted by female sandflies from Phlebotominae subfamily during their blood meals. In mammals, promastigotes are phagocytosed mainly by macrophages, differentiate into amastigotes and multiply.
View Article and Find Full Text PDFFood Funct
January 2025
Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China.
Indole-3-propionic acid (IPA), a metabolite produced by gut microbiota through tryptophan metabolism, has recently been identified as playing a pivotal role in bone metabolism. IPA promotes osteoblast differentiation by upregulating mitochondrial transcription factor A (Tfam), contributing to increased bone density and supporting bone repair. Simultaneously, it inhibits the formation and activity of osteoclasts, reducing bone resorption, possibly through modulation of the nuclear factor-κB (NF-κB) pathway and downregulation of osteoclast-associated factors, thereby maintaining bone structural integrity.
View Article and Find Full Text PDFPostgrad Med J
January 2025
Department of Pediatric Metabolic Diseases, University of Health Sciences, Ankara Etlik City Hospital, Ankara 06170, Turkey.
Metabolism is the name given to all of the chemical reactions in the cell involving thousands of proteins, including enzymes, receptors, and transporters. Inborn errors of metabolism (IEM) are caused by defects in the production and breakdown of proteins, fats, and carbohydrates. Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules, ⁓19-25 nucleotides long, hairpin-shaped, produced from DNA.
View Article and Find Full Text PDFScand J Gastroenterol
January 2025
Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Xiamen Branch, Xiamen, China.
Background: Evaluate the clinical significance of esophagogastric junction (EGJ) morphology and esophagogastric junction contractile integral (EGJ-CI) in refractory gastroesophageal reflux disease (RGERD) patients.
Methods: From June 2021 to June 2023, 144 RGERD patients underwent comprehensive evaluation, recording symptom scores, demographic data. GERD classification (NERD or RE, A-D) was based on endoscopic findings.
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