Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by $U$ and $g$, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between $U$ and $g$. As $U$ ($g$) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

Molecular basis of the fructose-2,6-bisphosphatase reaction of PFKFB3: Transition state and the C-terminal function

The molecular basis of fructose-2,6-bisphosphatase (F-2,6-P 2ase) of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) was investigated using the crystal structures of the human inducible form (PFKFB3) in a phospho-enzyme intermediate state (PFKFB3-P•F-6-P), in a transition state-analogous complex (PFKFB3•AlF 4), and in a complex with pyrophosphate (PFKFB3•PP i) at resolutions of 2.45, 2.2, and 2.3 Å, respectively. Trapping the PFKFB3-P•F-6-P intermediate was achieved by flash cooling the crystal during the reaction, and the PFKFB3•AlF 4 and PFKFB3•PP i complexes were obtained by soaking. The PFKFB3•AlF 4 and PFKFB3•PP i complexes resulted in removing F-6-P from the catalytic pocket. With these structures, the structures of the Michaelis complex and the transition state were extrapolated. For both the PFKFB3-P formation and break down, the phosphoryl donor and the acceptor are located within ∼5.1 Å, and the pivotal point 2-P is on the same line, suggesting an in-line transfer with a direct inversion of phosphate configuration. The geometry suggests that NE2 of His253 undergoes a nucleophilic attack to form a covalent N-P bond, breaking the 2O-P bond in the substrate. The resulting high reactivity of the leaving group, 2O of F-6-P, is neutralized by a proton donated by Glu322. Negative charges on the equatorial oxygen of the transient bipyramidal phosphorane formed during the transfer are stabilized by Arg252, His387, and Asn259. The C-terminal domain (residues 440-446) was rearranged in PFKFB3•PP i, implying that this domain plays a critical role in binding of substrate to and release of product from the F-2,6-P 2ase catalytic pocket. These findings provide a new insight into the understanding of the phosphoryl transfer reaction. © 2011 Wiley Periodicals, Inc

Effects of multi-stage dehumidified-air drying on the polyphenol content of Hydrocotyle bonariensis

Traditional drying methods involve high temperatures that degrade heat-sensitive compounds. Dehumidified-air drying, an alternative to traditional drying methods, is suitable for heat-sensitive compounds; however, it consumes a large amount of energy and is comparatively expensive. In this study, a multi-chamber dehumidified-air dryer was designed to dry Hydrocotyle bonariensis, and the retention of the polyphenol content of Hydrocotyle bonariensis under various drying conditions was examined. Multi-chamber dehumidified-air drying involves two chambers; each chamber was operated at temperatures of 30, 40, and 50°C with air volumetric flow rates of 30 and 50 L/min. The results indicated that the highest retention of total phenolic content and total flavonoid content, 24.67 mg of GAE/g dry weight (DW) and 2.204 mg of catechin/g DW, respectively, was obtained at 50°C with a 50 L/min air flow rate in the first drying chamber. Multi-stage dehumidified-air dryers have the potential to dry heat-sensitive products with reduced energy consumption

Kajian Analisis Engineering Dengan Metode Computational Fluid Dynamics

Computational fluid dynamic is fluid flow analysis in spesific system by mean of computer based simulation. The use of CFD to predict fluid flow in characteristic system which has specified conditions. The purpose of this research is to describe the procedural of simulation. The scope of this research is to verify the calculation result with the simulation result. The method of this research are iteratif calculaation and simulation. The result of iteratif calculation water outlet temperatur is of 71,88oC, while the simulation result for S1 is of 62,58 oC, S2 is of 79,44 oC, S3 is of 71,02oC, and S4 is of 71,68 oC. The difference of the result cause by the dimension of diameter tube, type of flow, and distribution of grid. The result of this research show that the accuration of simulation is depend on the intial engineering thingking, grid, and fluid flow specification. Key words: CFD, fluid, grid, simulatio

Anti-Tuberculosis Drugs and Adverse Events

Anti-tuberculosis (TB) drugs can cause adverse drug reactions, particularly the older second-line drugs. Early intervention and adequate management of adverse drug reactions are important to prevent complications. Laboratory testing at baseline and during treatment, in addition to clinical monitoring, is protocolized to improve patient and treatment management. This chapter provides an overview of the most frequent and severe adverse effects caused by the first-and second-line drugs used for the treatment of tuberculosis. An approach on how to manage the adverse drugs effects is briefly described.</p

Anti-Tuberculosis Drugs and Adverse Events

Anti-tuberculosis (TB) drugs can cause adverse drug reactions, particularly the older second-line drugs. Early intervention and adequate management of adverse drug reactions are important to prevent complications. Laboratory testing at baseline and during treatment, in addition to clinical monitoring, is protocolized to improve patient and treatment management. This chapter provides an overview of the most frequent and severe adverse effects caused by the first-and second-line drugs used for the treatment of tuberculosis. An approach on how to manage the adverse drugs effects is briefly described.</p