Aβ oligomers are potential targets for the diagnosis and therapy of Alzheimer's disease (AD). On the other hand, the molecule curcumin has been shown to possess significant therapeutic potential in many areas. In this paper, we use all-atom explicit solvent molecular dynamics simulations to study the effect of curcumin on the stability of Aβ amyloid protein oligomers. We observed that curcumin decreases the β-sheet secondary structural content within the Aβ oligomers without reducing the contacts between the monomers. The breaking of the β-sheet is found to be preceded by a deformation of the β-sheet structure due to hydrophobic interaction from the nearby curcumin. Furthermore, the π-stacking interaction between curcumin (keto ring and enol ring) and the aromatic residues of Aβ, which exists throughout the simulations, has also contributed to the diminishing of the β-sheet structure. Our analysis of the underwrapped amide-carbonyl hydrogen bonds reveals several stable dehydrons of the oligomer, especially the dehydron pair 34L and 41I, which curcumin tends to hover over. We have examined the paths of curcumin on the Aβ proteins and determined the common routes where curcumin lingers as it traverses around the Aβ. In consequence, our study has provided a detailed interaction picture between curcumin and the Aβ oligomers.

The aggregation of amyloid β peptides resulting in neurotoxic oligomers is an important but yet mysterious process in Alzheimer's disease development. Molecular dynamics simulations were performed to investigate the self-assembly of three full-length amyloid peptides in the zwitterionic dipalmitoylphosphatidylcholine and cholesterol mixed lipid bilayer. During the 1000 ns simulation, the residues 1-27 were found to interact preferentially with the lipid-aqueous interface region, while residues 28-42 show an inclination to remain inside the bilayer hydrophobic tail region. The interaction between peptides and lipids has facilitated the association of Aβ peptides. However, the interaction between cholesterol and peptides is inversely correlated with the extent of the peptide-peptide interactions. Our simulation has uncovered the formation of a short segment of parallel β-sheet between two peptide chains. In another chain, the N- and C-termini came close to each other. All the structural transitions indicate that our simulation has caught a glimpse of the complicated peptide oligomerization process. The full understanding of the underlying mechanism still requires further experimental and theoretical studies.

Spreading-basin methods have resulted in more than 130 million cubic metres of recharge to the unconfined Navajo Sandstone of southern Utah in the past decade, but infiltration rates have slowed in recent years because of reduced hydraulic gradients and (or) clogging. Trench infiltration is a promising alternative technique for increasing recharge and minimizing evaporation. This paper uses a variably saturated flow model to further investigate the relative importance of the following variables on rates of trench infiltration to unconfined aquifers: saturated hydraulic conductivity, trench spacing and dimensions, initial water-table depth, alternate wet/dry periods, and number of parallel trenches. Modelling results showed (1) increased infiltration with higher hydraulic conductivity, deeper initial water tables, and larger spacing between parallel trenches, (2) deeper or wider trenches do not substantially increase infiltration, (3) alternating wet/dry periods result in less overall infiltration than keeping the trenches continuously full, and (4) larger numbers of parallel trenches within a fixed area increases infiltration but with a diminishing effect as trench spacing becomes tighter. An empirical equation for estimating expected trench infiltration rates as a function of hydraulic conductivity and initial water-table depth was derived and can be used for evaluating feasibility of trench infiltration in other hydrogeologic settings. a The upper end of this range was expanded beyond the values determined from the retention curve modelling based on laboratory results because the simulated area of the VS2DI model is much larger, likely incorporating macropore features not present in core samples 3015 VARIABLY SATURATED MODELLING FOR OPTIMIZING TRENCH INFILTRATION

The absence of dislocation in both small and large articulations confirmed the efficacy of the dual mobility concept and suggested an advantage for chromium-cobalt sockets in reducing the rate of intraprosthetic dislocation and preventing blockage of the large articulation by a better performance in the friction couple. Granulomas were associated with wear in cemented titanium stems and with heads greater than 22 mm in diameter. Ten-year survival was 99% (censorship criterion: revision for socket failure); there was, however, one case of socket loosening with disappearance of the hydroxyapatite, indicating that surveillance should be continued in this cohort.

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