The dissociation mechanism of duplex DNA has been investigated in detail by collision-induced dissociation experiments at different collision regimes. MS/MS experiments were performed either in a quadrupole collision cell (hybrid quadrupole-TOF instrument) or in a quadrupole ion trap with different activation times and energies. In addition to the noncovalent dissociation of the duplex into the...

In the present study, the pH-dependent free radical-scavenging activity of betanin in the Trolox equivalent antioxidant capacity (TEAC) assay was determined. It was found that at a pH > 4 betanin is about 1.5-2.0-fold more active than some anthocyanins considered very good free radical scavengers as determined in the TEAC assay. The increase in the TEAC values of betanin with increasing pH is d...

A detailed thermochemical analysis of the alpha-cleavage and decarbonylation reactions of acetone and several ketodiesters was carried out with the B3LYP/6-31G* density functional method. The heats of formation of several ground-state ketones and radicals were calculated at 298 K to determine bond dissociation energies (BDE) and radical stabilization energies (RSE) as a function of substituents...

BACKGROUND/AIM The flavonoid quercetin exerts significant anti-inflammatory activity against chronic infections, including periodontal disease. However, it is unclear whether combination of quercetin with other flavonoids enhances antioxidant and anti-inflammatory activity. To clarify the molecular mechanism responsible for the anti-inflammatory activity of quercetin, we investigated the antiox...

The C-H bond dissociation processes of n-hexane and isohexane involve 23 and 13 conformational structures, respectively in the parent molecules and 14-45 conformational structures in each of the seven isomeric products that we studied. Here we use the recently developed multi-structural (MS) thermodynamics method and CCSD(T)-F12a/jul-cc-pVTZ//M06-2X/6-311+G(2df,2p) potential energy surfaces to ...

A DFT-SOFM-RBFNN method is proposed to improve the accuracy of DFT calculations on Y-NO (Y = C, N, O, S) homolysis bond dissociation energies (BDE) by combining density functional theory (DFT) and artificial intelligence/machine learning methods, which consist of self-organizing feature mapping neural networks (SOFMNN) and radial basis function neural networks (RBFNN). A descriptor refinement s...

The five-membered cyclic esters, or γ-lactones, are promising candidates as biofuel additives and green solvent components. A comprehensive study of thermochemical kinetic properties γ-butyrolactone (GBL), γ-valerolactone (GVL), γ-caprolactone (GCL), γ-heptalactone (GHL) has been conducted. entropy, , specific heat, enthalpy function, the enthalphy formation at 298.15 K, well adiabatic ionizati...

BACKGROUND A previous study from our laboratory showed that polybrominated diphenyl ethers (PBDEs) were metabolized to hydroxylated PBDEs (HO-PBDEs) in mice and that para-HO-PBDEs were the most abundant and, potentially, the most toxic metabolites. OBJECTIVE The goal of this study was to determine the concentrations of HO-PBDEs in blood from pregnant women, who had not been intentionally or o...