Roles of multiple acetoacetyl coenzyme A reductases in polyhydroxybutyrate biosynthesis in Ralstonia eutropha H16.

The bacterium Ralstonia eutropha H16 synthesizes polyhydroxybutyrate (PHB) from acetyl coenzyme A (acetyl-CoA) through reactions catalyzed by a β-ketothiolase (PhaA), an acetoacetyl-CoA reductase (PhaB), and a polyhydroxyalkanoate synthase (PhaC). An operon of three genes encoding these enzymatic steps was discovered in R. eutropha and has been well studied.

Molecular and nanostructural mechanisms of deformation, strength and toughness of spider silk fibrils.

Spider dragline silk is one of the strongest, most extensible and toughest biological materials known, exceeding the properties of many engineered materials including steel. Silk features a hierarchical architecture where highly organized, densely H-bonded beta-sheet nanocrystals are arranged within a semiamorphous protein matrix consisting of 3(1)-helices and beta-turn protein structures. By using a bottom-up molecular-based approach, here we develop the first spider silk mesoscale model, bridging the scales from Angstroms to tens to potentially hundreds of nanometers.

Thermal annealing treatment to achieve switchable and reversible oleophobicity on fabrics.

Surfaces that are strongly nonwetting to oil and other low surface tension liquids can be realized by trapping microscopic pockets of air within the asperities of a re-entrant texture and generating a solid-liquid-vapor composite interface. For low surface tension liquids such as hexadecane (gamma(lv) = 27.5 mN/m), this composite interface is metastable as a result of the low value of the equilibrium contact angle.

Synthesis of amides and lactams in supercritical carbon dioxide.

Supercritical carbon dioxide can be employed as an environmentally friendly alternative to conventional organic solvents for the synthesis of a variety of carboxylic amides. The addition of amines to ketenes generated in situ via the retro-ene reaction of alkynyl ethers provides amides in good yield, in many cases with ethylene or isobutylene as the only byproducts of the reaction. Reactions with ethoxy alkynes are performed at 120-130 degrees C, whereas tert-butoxy derivatives undergo the retro-ene reaction at 90 degrees C.

Dispersion-managed solitons with net positive dispersion.

Propagation of dispersion-managed solitons in the net positive-dispersion regime is studied. A new form of sideband generation that is due to perturbations is identified. Some collision anomalies are pointed out.

Consistency effects between objects in scenes.

How does context influence the perception of objects in scenes? Objects appear in a given setting with surrounding objects. Do objects in scenes exert contextual influences on each other? Do these influences interact with background consistency? In three experiments, we investigated the role of object-to-object context on object and scene perception. Objects (Experiments 1 and 3) and backgrounds (Experiment 2) were reported more accurately when the objects and their settings were consistent than when they were inconsistent, regardless of the number of foreground objects.

Structure and function in rhodopsin: correct folding and misfolding in point mutants at and in proximity to the site of the retinitis pigmentosa mutation Leu-125-->Arg in the transmembrane helix C.

L125R is a mutation in the transmembrane helix C of rhodopsin that is associated with autosomal dominant retinitis pigmentosa. To probe the orientation of the helix and its packing in the transmembrane domain, we have prepared and studied the mutations E122R, I123R, A124R, S127R, L125F, and L125A at, and in proximity to, the above mutation site. Like L125R, the opsin expressed in COS-1 cells from E122R did not bind 11-cis-retinal, whereas those from I123R and S127R formed the rhodopsin chromophore partially.