Verification of a model to predict the influence of particle inertia and gravity on a decaying turbulent particle-laden flow

In an earlier publication some of the authors presented a theoretical model for the calculation of the influence of particle inertia and gravity on the turbulence in a stationary particle-laden flow. In the present publication the model is extended for application to a decaying suspension. Also a comparison is given between predictions made with the model and experimental data (own data and data reported in the literature) on a decaying turbulent flow with particles in a water tunnel or in a wind tunnel. For most of the experiments a prediction with reasonable accuracy and an interpretation is possible by means of the model.     

A cellular automata model of the soluble state

Cellular automata models of solubilities in a solvent (water) have been dynamically synthesized. Rules relatingwater‐water, water‐solute, and solute‐solute relationships have been systematically varied in order to assess their influence on the emergent property of solubility. The results reveal the prominent influence of rules governing the probabilities of solute‐water joining and breaking. This influence manifests itself in significant changes in the emergent properties of relative solubility and solubility changes with water“temperature”. The study demonstrates the validity and potential value of cellular automata to model solution phenomena. This revised version was published online in July 2006 with corrections to the Cover Date.     

Probing the lower size limit for protein-like fold stability: ten-residue microproteins with specific, rigid structures in water

Mutational optimization of two long-range interactions first observed in Ac-WINGKWT-NH2, (a) bifurcated H-bonding involving the threonine amide H(N) and side chain OH and the N-terminal acetyl carbonyl and (b) an H-bond between the entgegen-H(N) of the C-terminal amide and the indole ring of Trp6 that stabilizes a face-to-edge indole/indole interaction between Trp1 and Trp6, has afforded < or = 10 residue systems that yield a remarkably stable fold in water. Optimization was achieved by designing a hydrophobic cluster that sequesters these H-bonds from solvent exposure. The structures and extent of amide H/D exchange protection for CH3CH2CO-WI pGXWTGPS (p = D-Pro, X = Leu or Ile) were determined. These two systems are greater than 94% folded at 298 K (97.5% at 280 K) with melting temperatures > 75 degrees C. The fold appears to display minimal fluxionality; a well-converged NMR structure rationalizes all of the large structuring shifts observed, and we suggest that these designed constructs can be viewed as microproteins.     

Water-soluble through-bond energy transfer cassettes for intracellular imaging

A special, water-soluble, fluorescent probe 1 was designed. This consisted of a fluorescein-based component to harvest irradiation at 488 nm and a rhodamine-based part designed to emit it at a significantly longer wavelength. This cassette was used to label an illustrative protein called ACBP. Evidence was accumulated to support the assertion that ACBP-1 bound its native ligand with a binding constant similar to that of the unlabeled protein, and retained its secondary structure (CD). ACBP-1 was imported into cells using the Chariot peptide. Confocal images proved that some ACBP-1 localized into the nucleus (as expected) and, most significantly, it could be visualized more effectively by irradiating at the donor (fluorescein-like) part of the cassette, than the acceptor (rhodamine-like) part. Overall, this study demonstrates that cassettes of this kind can label a protein without significantly perturbing its function or secondary structure and they can be visualized effectively via irradiation of the donor and observation of the acceptor fluorescence.