Modeling the tetraphenylalanine-PEG hybrid amphiphile: from DFT calculations on the peptide to molecular dynamics simulations on the conjugate

The conformational properties of the hybrid amphiphile formed by the conjugation of a hydrophobic peptide with four phenylalanine (Phe) residues and hydrophilic poly(ethylene glycol), have been investigated using quantum mechanical calculations and atomistic molecular dynamics simulations. The intrinsic conformational preferences of the peptide were examined using the building-up search procedure combined with B3LYP/ 6-31G(d) geometry optimizations, which led to the identification of 78, 78, and 92 minimum energy structures for the peptides containing one, two, and four Phe residues. These peptides tend to adopt regular organizations involving turn-like motifs that define ribbon or helicallike arrangements. Furthermore, calculations indicate that backbone ... side chain interactions involving the N-H of the amide groups and the pi clouds of the aromatic rings play a crucial role in Phe-containing peptides. On the other hand,MD simulations on the complete amphiphile in aqueous solution showed that the polymer fragment rapidly unfolds maximizing the contacts with the polar solvent, even though the hydrophobic peptide reduce the number of waters of hydration with respect to an individual polymer chain of equivalent molecular weight. In spite of the small effect of the peptide in the hydrodynamic properties of the polymer, we conclude that the two counterparts of the amphiphile tend to organize as independent modules.

Milk, dairy products and consumer health: a short review

There appears to be a large mis-match between (1) the advice given on milk/dairy foods by various authorities, (2) public perceptions of harm from the consumption of milk and dairy products and, (3) the evidence from long-term prospective cohort studies. These studies provide convincing evidence that increased consumption of milk can lead to reductions in the risk of vascular disease and possibly some cancers and provide an overall survival advantage. The volume of evidence available for milk products such as cheese and butter is however surprisingly limited and too small to come to any clear conclusions as to their effects on health.

Chronic disease risk associated with different dietary saturated fatty acids

This chapter compares the risks of chronic disease, and cardiovascular disease in particular, associated with consumption of different saturated fatty acids. Emphasis is placed on the effects of stearic acid as this has potential to replace trans fatty acids in certain manufactured food products. The chapter first reviews the effects of individual saturated fatty acids on blood lipids, including cholesterol, as these are commonly used as markers of disease risk. It then looks directly at evidence in relation to health outcomes. Finally, recent evidence specifically on the effect of stearic acid relative to other fatty acids, including trans fatty acids, is summarised.

Brain computer interface control via functional connectivity dynamics

The dynamics of inter-regional communication within the brain during cognitive processing – referred to as functional connectivity – are investigated as a control feature for a brain computer interface. EMDPL is used to map phase synchronization levels between all channel pair combinations in the EEG. This results in complex networks of channel connectivity at all time–frequency locations. The mean clustering coefficient is then used as a descriptive feature encapsulating information about inter-channel connectivity. Hidden Markov models are applied to characterize and classify dynamics of the resulting complex networks. Highly accurate levels of classification are achieved when this technique is applied to classify EEG recorded during real and imagined single finger taps. These results are compared to traditional features used in the classification of a finger tap BCI demonstrating that functional connectivity dynamics provide additional information and improved BCI control accuracies.