Protein folding tames chaos

Protein folding produces characteristic and functional three-dimensional structures from unfolded polypeptides or disordered coils. The emergence of extraordinary complexity in the protein folding process poses astonishing challenges to theoretical modeling and computer simulations. The present work introduces molecular nonlinear dynamics (MND), or molecular chaotic dynamics, as a theoretical framework for describing and analyzing protein folding. We unveil the existence of intrinsically low dimensional manifolds (ILDMs) in the chaotic dynamics of folded proteins. Additionally, we reveal that the transition from disordered to ordered conformations in protein folding increases the transverse stability of the ILDM. Stated differently, protein folding reduces the chaoticity of the nonlinear dynamical system, and a folded protein has the best ability to tame chaos. Additionally, we bring to light the connection between the ILDM stability and the thermodynamic stability, which enables us to quantify the disorderliness and relative energies of folded, misfolded and unfolded protein states. Finally, we exploit chaos for protein flexibility analysis and develop a robust chaotic algorithm for the prediction of Debye-Waller factors, or temperature factors, of protein structures

Consumer’s attitudes and willingness-to-pay for Green food in Beijing

A survey in random-selected supermarkets in Beijing, the capital city of China, is reported to identify the attitudes and perceptions of consumers toward green-labeled milk, as well as their willingness to pay (WTP) for it, and to determine the factors that affect their WTP. The study reveals that the majority of households are quite familiar with green food and most of them take positive attitudes towards them, while with certain anxieties. Both remarkable preferences for location and branding in milk purchase and neglects for quality and safety are found in the consumers’ purchase pattern. The willingness to pay are concentrated in a range of 5 - 10 percent premium than ordinary milk, and age, the perception of green food and the access to information serve as the main factors influencing WTP value