Mechanisms for the activation of water, ammonia, and other small molecules by the PCcarbeneP nickel pincer complex were studied computationally with the aid of density functional theory. The calculation results indicate that the strongly donating, nucleophilic carbene center can engage in a variety of heterolytic splitting of E-H (E=H, C, N, O) bonds, some of which are reversible. The cleavage of E-H bonds across the Ni=C bond represents a new mode of bond activation by ligand cooperativity in nickel pincer complex.
View Article and Find Full Text PDFThe mechanism of Maillard reaction has been investigated by means of density functional theory calculations in the gaseous phase and aqueous solution. The Maillard reaction is a cascade of consecutive and parallel reaction. In the present model system study, glucose and glycine were taken as the initial reactants.
View Article and Find Full Text PDFIn the brain, astrocytes play an essential role with their multiple functions and sophisticated structure, as surrounded by a fractal environment which has not been available in our traditional cell culture. Water-repellent fractal tripalmitin (PPP) surfaces can imitate the fractal environment in vivo, so the morphology and biochemical characterization of astrocytes on these surfaces are examined. Water-repellent fractal PPP surface can induce astrocytes to display sophisticated morphology with smaller size of cell area, longer and finer filopodium-like processes, and higher morphological complexity.
View Article and Find Full Text PDFThe density functional theory (DFT) calculations at the M06-2X/6-31++G(d,p) level have been performed to explore the molecular structure, electronic structure, C-H bond dissociation enthalpy, and reaction enthalpies for five isodesmic reactions of a high energy-density endothermic hydrocarbon fuel JP-10. On the basis of the calculations, it is found that the carbonium ion C-6 isomer formed from the catalytic cracking at the C₆ site of JP-10 has the lowest energy, and the R-5 radical generated from the thermal cracking at the C₅ site of JP-10 is the most stable isomer. Furthermore, a series of hypothetical and isodesmic work reactions containing similar bond environments are used to calculate the reaction enthalpies for target compounds.
View Article and Find Full Text PDFDensity functional theory (DFT) calculations have been carried out to investigate the thermal cracking pathways of JP-10, a high energy density hydrocarbon fuel. Thermal cracking mechanisms are proposed, as supported by our previous experimental results (Xing et al. in Ind Eng Chem Res 47:10034-10040, 2008).
View Article and Find Full Text PDFIntroduction: Hypothyroidism and subclinical hypothyroidism may be associated with hypertension and metabolic syndrome. The aim of this study was to investigate the relationship between thyroid-stimulating hormone (TSH) and blood pressure, as well as the relationship between thyroid function and insulin resistance in middle-aged and elderly Chinese.
Methods: This was a cross-sectional, community-based study.
Fibroblast growth factor 21 (FGF-21) is a new metabolic regulator with beneficial effects on lipid and glucose metabolism in animal models of diabetes mellitus. The aim of this study was to explore the relationship between FGF-21 and diabetic nephropathy in humans. Serum FGF-21 levels were determined in groups of control (n = 50) and type 2 diabetes mellitus (T2DM) patients with normoalbuminuria (n = 158), microalbuminuria (n = 68), and macroalbuminuria (n = 38) using enzyme-linked immunosorbent assay.
View Article and Find Full Text PDFThe intermolecular interactions between Au(n) (n = 3-4) clusters and selected amino acids cysteine and glycine have been investigated by means of density functional theory (DFT). Present calculations show that the complexes possessing Au-NH(2) anchoring bond are found to be energetically favored. The results of NBO and frontier molecular orbitals analysis indicate that for the complex with anchoring bonds, lone pair electrons of sulfur, oxygen, and nitrogen atoms are transferred to the antibonding orbitals of gold, while for the complex with the nonconventional hydrogen bonds (Au···H-O), the lone pair electrons of gold are transferred to the antibonding orbitals of O-H bonds during the interaction.
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