The vesicular cleavage of activated phosphate esters by hydroxide and fluoride ions — artifactual endovesicular reactions

Previously reported endovesicular reactions in the cleavage of $\text{p}$-nitrophenyl diphenyl phosphate by hydroxide (or fluoride) ions in vesicles of dihexadecyldimethylammonium bromide appear to be artifacts.     

Mechanistic alteration in micellar peptide esterolysis reactions

Buffer or CTACl-catalyzed basic cleavages of $\text{Z}$-$\text{D}$- or $\text{L}$-AA-$\text{L}$-Pro $\text{p}$-nitrophenyl esters proceed mainly via intramolecular cyclization to diketopiperazines. These reactions are more facile with $\text{DL}$ than with $\text{LL}$ substrates.     

Refinement of linear polymer crystal structures determined from electron diffraction data

The reliability of linear polymer structures determined by using electron diffraction data is investigated. The results of n-beam dynamical calculations and kinematic calculations which take account of crystal bending are compared with experimental structure factors for five published structures. In specific cases, both dynamical scattering and crystal bending effects are found to be important. Finally, guidelines are given for obtaining electron diffraction data which are optimal for structure solution.     

Single axial mode pumping and external mirror operation of a pulsed spin-flip Raman laser at 10.6 μm

By the addition of an external cavity to a single axial mode, TEA CO₂ laser pumped, In Sb spin-flip Raman laser, a tenfold increase in first Stokes output and a twenty-five fold increase in second Stokes and anti-Stokes outputs has been observed.     

Fundamental solutions of degenerate or singular elliptic equations

Exitence of fundamental solutions is established for a class of degenerate or singular, second-order, linear elliptic partial differential equations. This class contains, for example, Tricomi's equation in the upper half-plane which arises in the study of aerodynamics; the equation of Weinstein's generalized axially symmetric potential theory which arises in the study of fluid dynamics and elasticity; and Schrödinger's equation with a singular potential which arises in quantum mechanics.     

Morphological instability in InAs/GaSb superlattices due to interfacial bonds

Synchrotron x-ray diffraction is used to compare the misfit strain and composition in a self-organized nanowire array in an InAs/GaSb superlattice with InSb interfacial bonds to a planar InAs/GaSb superlattice with GaAs interfacial bonds. It is found that the morphological instability that occurs in the nanowire array results from the large misfit strain that the InSb interfacial bonds have in the nanowire array. Based on this result, we propose that tailoring the type of interfacial bonds during the epitaxial growth of III-V semiconductor films provides a novel approach for producing the technologically important morphological instability in anomalously thin layers.