Four [Ru(NN)(3)](2+) complexes (NN = polypyridine) with ligands of varying hydrophobicity with different charges +2, 0 and -4 were synthesized. The photophysics and photoinduced electron transfer reactions of these Ru(II)-complexes with dimethylaniline (DMA) as the quencher have been studied in aqueous medium and ionic and non-ionic micellar medium. The extent of binding of the complexes with the surfactant interface is evident from the calculated binding constant values (K). Dimethylaniline (DMA) being a neutral quencher, the hydrophobic and electrostatic interactions competing with one another and their combined effect with the surfactants were reported by observing the quenching rate constant (k(q)) values. The formation of anilinium cation radical in transient absorption spectrum confirms the excited state electron transfer reactions of ruthenium(II) complexes with dimethylaniline. The calculated rate constant values (k(q)) are in good agreement with the experimental k(q) values giving quantitative evidence for the bimolecular reductive quenching rate constant for the complexes with DMA. Pseudophase ion exchange model is successfully applied to analyse the quenching data.
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http://dx.doi.org/10.1007/s10895-014-1491-z | DOI Listing |
ACS Appl Bio Mater
January 2025
Department of Chemical Engineering, Indian Institute of Technology Tirupati, Tirupati, Andhra Pradesh 517619, India.
In the fast-paced quest for early cancer detection, noninvasive screening techniques have emerged as game-changers, offering simple and accessible avenues for precession diagnostics. In line with this, our study highlights the potential of silver nanoparticle-decorated titanium carbide MXene nanosheets (TiC_AgNPs) as an electroactive interface for the noninvasive diagnosis of oral carcinoma based on the prevalence of the salivary biomarker, tumor necrosis factor-α (TNF-α). An in situ reduction was utilized to synthesize the TiC_AgNPs nanohybrid, wherein TiC acts as the reducing agent, and the resulting nanohybrid was subjected to various characterization techniques to examine the optical, structural, and morphological attributes.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104.
Class I major histocompatibility complex (MHC-I) proteins play a pivotal role in adaptive immunity by displaying epitopic peptides to CD8+ T cells. The chaperones tapasin and TAPBPR promote the selection of immunogenic antigens from a large pool of intracellular peptides. Interactions of chaperoned MHC-I molecules with incoming peptides are transient in nature, and as a result, the precise antigen proofreading mechanism remains elusive.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
The Marcus semi-classical and quantum theories of electron transfer (ET) have been extensively used to understand and predict tunneling ET reaction rates in the condensed phase. Previously, the traditional Marcus two-state model has been extended to a three-state model, which assumes a harmonic dependence of donor (D), bridge (B), and acceptor (A) free energies on the reaction (e.g.
View Article and Find Full Text PDFJ Cell Biol
March 2025
Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA.
The interplay between ribosomal protein (RP) composition and mitochondrial function is essential for energy homeostasis. Balanced RP production optimizes protein synthesis while minimizing energy costs, but its impact on mitochondrial functionality remains unclear. Here, we investigated haploinsufficiency for RP genes (rps-10, rpl-5, rpl-33, and rps-23) in Caenorhabditis elegans and corresponding reductions in human lymphoblast cells.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Southern University of Science and Technology, Department of Materials Science and Engineering, NO.1088,Xueyuan Avenue,Nanshan District, 518055, Shenzhen, CHINA.
Tin dioxide (SnO2) stands as a promising material for the electron transport layer (ETL) in perovskite solar cells (PSCs) attributed to its superlative optoelectronic properties. The attainment of superior power conversion efficiency hinges critically on the preparation of high-quality SnO2 thin films. However, conventional nanoparticle SnO2 colloids often suffer from inherent issues such as numerous oxygen vacancy defects and film non-uniformity.
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