Structural Determinants of the Binding and Activation of Estrogen Receptor α by Phenolic Thieno[2,3-d]pyrimidines

Synthetic, structural, and computational approaches were used to solve the puzzle as to how a phenolic nonsteroidal estrogen 1 with only a single H-bond to its receptor was more potent than an isomer 2 which formed an intricate network of H-bonds. Synthesis of a series of substituted phenols revealed that pK_a was not a determinant of estrogenic activity. First-principles calculation also failed to explain the difference in activity of 1 and 2 . Molecular dynamics revealed that 1 formed a more stable receptor complex compared to 2 , which may explain its increased activity despite forming fewer apparent H-bonds with the protein.     

A theory for concentrated fiber suspensions with strong fiber-fiber interactions

A theory is presented for the flow-induced fiber orientation and stress in fiber-reinforced polymer composites with planar fiber orientation. The rate of change of fiber orientation is given as a function of the strain rate in the continuum and the probabilistic effects of physical inter-fiber contacts. The continuum stress is calculated from the stress in the fluid and fibers, where fiber stress is a result of the local disturbance in the fluid velocity field and of the inter-fiber contact forces. Fiber orientation is described via a probability density function whose transport equation has the form of a standard advection-diffusion equation with an orientation-dependent rotary diffusion. This equation is solved using a finite difference scheme and the results are presented.