The growth and patterning of Drosophila wing and notum primordia depend on their subdivision into progressively smaller domains by secreted signals that emanate from localized sources termed organizers. While the mechanisms that organize the wing primordium have been studied extensively, those that organize the notum are incompletely understood. The genes odd-skipped (odd), drumstick (drm), sob...

Self-assembled, hollow molecular structures are appealing as synthetic hosts for mediating chemical reactions. However, product binding has inhibited catalytic turnover in such systems, and selectivity has rarely approached the levels observed in more structurally elaborate natural enzymes. We found that an aqueous organopalladium cage induces highly unusual regioselectivity in the Diels-Alder ...

d n d T he iPIX by Saremi et al. (1) in this issue of iJACC highlights the precision of current imaging techniques in displaying the complex 3-dimensional structure of the right entricle (RV). The investigators illustrate the inricacy of normal RV geometry, highlighting the istributions of anatomical folds, irregular trabeulations and, more importantly, the RV inundibulum. These remarkable pict...

Energy savings by reducing the thermal and mechanical losses in machines is of major concern due to continuous depletion of energy resources. Frictional losses of engine components cause energy losses leading to high fuel consumption. In piston assembly, piston skirt and liner interaction contribute as much as a frictional loss as the piston rings but more studies have been focused on piston ri...

We used a capacitive technique to determine the radial clearance between the piston and cylinder of a gas piston gauge. This method determines the effective area of a piston gauge pressure standard, independent of calibration against another piston gauge or manometer, as long as the diameter of the piston is dimensionally measured. It also allows an independent determination of piston gauge dis...

A liquid piston concept is proposed to improve the efficiency of gas compression and expansion. Because a liquid can conform to an irregular chamber volume, the surface area to volume ratio in the gas chamber can be maximized using a liquid piston. This creates near-isothermal operation, which minimizes energy lost to heat generation. A liquid piston eliminates gas leakage and replaces sliding ...

In the present paper, effect of combustion chamber design parameters on improvement efficiency (the heat generated inside chamber) and enhancement in pollution rates (heat emissions) from a four-stroke, spark-ignition engine has been studied experimentally theoretically. Two different programs, Gaseq Ansys, were used to simulate shape, turbulent kinetic energy, intake temperature, pressure, par...

The B3LYP/6-31++G** density functional calculations were used to obtain minimum geometries and interaction energies between the molecular hydrogen and nanostructures of fullerenes, C20 (cage), C20 (bowl), C19Si (bowl, penta), C19Si (bowl, hexa). The H2 molecule is set as adsorbed in the distance of 3Å at vertical position from surface above the pentagonal and hexagonal sites of nanostructures. ...