Acrolein detection based on alcohol dehydrogenase inhibition

This paper presents the effect of acrolein on three dehydrogenases and proposes a fast spectrometric method for acrolein analysis. We have found that alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (AlDH) are inhibited by low acrolein concentrations (0.2?mM) while inhibition of glutamate dehydrogenase (GDH) is not observed even at higher acrolein concentrations (1?mM). Acrolein is a suicide substrate for AlDH and ADH inhibition by acrolein is competitive. Cysteine (L-Cys) and glutathione (GSH) react with acrolein and thus reduce its expected inhibitory effect. ADH was chosen to develop a spectrophotometric method for acrolein analysis based on enzyme inhibition. The calibration curve is linear between 0.2 and 1.0?mM acrolein.     

Interface charge transfer process in ZnO:Mn/ZnS nanocomposites

Journal of Nanoparticle Research - TiO2 photocatalysts co-doped with F and Fe were synthesized by a sol–gel method. Synergistic effects of F and Fe in the co-doped TiO2 were verified by NH3...     

Synthesis,characterization, and biological activity of some complex combinations of nickel with α-ketoglutaric acid and 1-(o-tolyl)biguanide

The four divalent nickel complexes having α-ketoglutaric acid (H₂A) and 1-(o-tolyl)biguanide (TB) ligands have been synthesized, characterized, and tested for antibacterial and antitumor activity.The proposed formulas for these complexes are [Ni(TB)(HA)(H₂O)₂]Cl (C1), [Ni(TB)(HA)(H₂O)₂]Br (C2), [Ni(TB)(HA)]NO₃·H₂O (C3), and [Ni(TB)(HA)]CH₃COO (C4), where HA represents deprotonated H₂A.For the four complexes and for the ligands used in the synthesis, the antibacterial activity against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 and antitumor activity in HeLa tumor cells were tested. A moderate cytotoxic effect of C3 and C4 complexes has been observed on the development and metabolic activity of HeLa cells, whereas C1 and C2 ligands have a very low effect on them.The synthesized complexes (obtained) inhibit adherence to the inert substrate of bacterial strains S. aureus and P. aeruginosa; therefore, they may be candidates for (potential) therapeutic applications.     

Foundational aspects of singular integrals

We investigate integration of classes of real-valued continuous functions on (0,1]$(0,1]$. Of course difficulties arise if there is a non-L¹$L^1$ element in the class, and the Hadamard finite part integral (p.f.) does not apply. Such singular integrals arise naturally in many contexts including PDEs and singular ODEs.     

Electron-deficient adduct site in the ring opening of methylcyclopentane (MCP) on tungsten-oxide-supported Pt,Ir and Pt–Ir catalysts

The activities of Pt/WO₂, Ir/WO₂ and Pt–Ir/WO₂ toward the conversion of methylcyclopentane (MCP) were investigated. The catalysts were prepared using impregnation and co-impregnation methods and were characterized by SEM, XRD, N₂-sorption and TEM investigations. The most active catalyst toward the conversion of MCP, irrespective of the temperature, was Ir/WO₂. The order of the reactivity was Ir/WO₂ > Pt–Ir/WO₂ > Pt/WO₂. Strong metal–support interactions (SMSI) were observed for all the catalysts over the entire investigated temperature range. At 400 °C, the Pt and Pt–Ir showed 100% selectivity toward ring-enlargement reactions associated with the presence of electron-deficient adduct sites on the reducible acidic WO₂ support. Ring opening occurred over all the catalysts in three positions, resulting in the formation of 2-methylpentane (2-MP), 3-methylpentane (3-MP), and n-hexane (n-H). Difficulty in breaking the secondary – tertiary carbon bonds was observed predominantly on the Ir catalyst, which opens the MCP ring via a selective mechanism.     

Global Solutions to Nonlinear Two-Phase Free Boundary Problems

We classify global Lipschitz solutions to two-phase free boundary problems governed by concave fully nonlinear equations as either two-plane solutions or solutions to a one-phase problem. © 2019 Wiley Periodicals, Inc.     

Characterization of Alzheimer's-like paired helical filaments from the core domain of tau protein using solid-state NMR spectroscopy

The polymerization of the microtubule-associated protein tau into paired helical filaments (PHFs) represents one of the hallmarks of Alzheimer's disease. We employed solid-state nuclear magnetic resonance (NMR) to investigate the structure and dynamics of PHFs formed in vitro by the three-repeat-domain (K19) of protein tau, representing the core of Alzheimer PHFs. While N and C termini of tau monomers in PHFs are highly dynamic and solvent-exposed, the rigid segment consists of three major beta-strands. Combination of through-bond and through-space ssNMR transfer methods with water-edited ((15)N, (13)C) and ((13)C, (13)C) correlation experiments suggests the existence of a fibril core that is largely built by repeat unit R3, flanked by surface-exposed units R1 and R4. Solid-state NMR, circular dichroism, and the fibrillization behavior of a K19 mutant furthermore indicate that electrostatic interactions play a central role in stabilizing the K19 PHFs.