A new method to convert the potential of an ion-selective electrode to concentration or activity in potentiometric titration is proposed. The advantage of this method is that the electrode standard potential and the slope of the calibration curve do not have to be known. Instead two activities on the titration curve have to be estimated e.g. the starting activity before the titration begins and the activity at the end of the titration in the presence of large excess of titrant. This new method is beneficial when the analyte is in a complexed matrix or in a harsh environment which affects the properties of the electrode and the traditional calibration procedure with standard solutions cannot be used. The new method was implemented both in a method of linearization based on the Grans's plot and in determination of the stability constant of a complex and the concentration of the complexing ligand in the sample. The new method gave accurate results when using titrations data from experiments with samples of known composition and with real industrial harsh black liquor sample. A complexometric titration model was also developed.
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http://dx.doi.org/10.1016/j.aca.2015.05.056 | DOI Listing |
Sci Rep
December 2024
Research Centre for Biomedical Engineering (RCBE), School of Science and Technology, City, University of London, Northampton Square, London, EC1V 0HB, UK.
Traditional methods for management of mental illnesses in the post-pandemic setting can be inaccessible for many individuals due to a multitude of reasons, including financial stresses and anxieties surrounding face-to-face interventions. The use of a point-of-care tool for self-management of stress levels and mental health status is the natural trajectory towards creating solutions for one of the primary contributors to the global burden of disease. Notably, cortisol is the main stress hormone and a key logical indicator of hypothalamic-pituitary adrenal (HPA) axis activity that governs the activation of the human stress system.
View Article and Find Full Text PDFBAY 2413555 is a novel selective and reversible positive allosteric modulator of the type 2 muscarinic acetylcholine (M2) receptor, aimed at enhancing parasympathetic signaling and restoring cardiac autonomic balance for the treatment of heart failure (HF). This study tested the safety, tolerability and pharmacokinetics of this novel therapeutic option. REMOTE-HF was a multicenter, double-blind, randomized, placebo-controlled, phase Ib dose-titration study with two active arms.
View Article and Find Full Text PDFNat Commun
December 2024
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
The general control non-repressible 5 (GCN5)-related N-acetyltransferase (GNAT) SbzI, in the biosynthesis of the sulfonamide antibiotic altemicidin, catalyzes the transfer of the 2-sulfamoylacetyl (2-SA) moiety onto 6-azatetrahydroindane dinucleotide. While most GNAT superfamily utilize acyl-coenzyme A (acyl-CoA) as substrates, SbzI recognizes a carrier-protein (CP)-tethered 2-SA substrate. Moreover, SbzI is the only naturally occurring enzyme that catalyzes the direct incorporation of sulfonamide, a valuable pharmacophore in medicinal chemistry.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
The lack of a robust system to reproducibly propagate HRV-C, a family of viruses refractory to cultivation in standard cell lines, has substantially hindered our understanding of this common respiratory pathogen. We sought to develop an organoid-based system to reproducibly propagate HRV-C, and characterize virus-host interaction using respiratory organoids. We demonstrate that airway organoids sustain serial virus passage with the aid of CYT387-mediated immunosuppression, whereas nasal organoids that more closely simulate the upper airway achieve this without any intervention.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Cancer Nanomedicine Lab, Department of Zoology, Periyar University, Salem, TN, India.
We designed a new cyanide sensing probe by one-step synthesis and evaluated it using UV-vis and fluorescent techniques. The active moiety of (Z)-3-(4-(methylthio) phenyl)-2-(4-nitrophenyl) acrylonitrile (NCS) demonstrated fluorescence. The probe NCS showed turn-off fluorescence in the presence of cyanide (CN¯), which has a higher selectivity and sensitivity than other anions.
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