A weight-function approach for determining watershed initial conditions for combustion waves

In many generic combustion models, one finds that a combustionwave will develop with a specific wave speed. However, thereare possible initial temperature profiles which do not evolveinto such waves, but rather die out to the ambient temperature.There can exist, in some models, a clear distinction betweenthose initial conditions that do evolve into combustion wavesand those that do not; this is sometimes referred to as thewatershed initial condition. When fuel consumption is consideredto be negligible, analytical methods can be used to obtain theexact watershed. In this paper, we consider the problem of determiningpseudo-watersheds and ascertaining the relationship betweenthese pseudo-watersheds and the exact watersheds. In the processa novel weight-function approach for infinite spatial domainsis developed.     

Synthesis of cytotoxic cyanobactin,Wewakazole B

We report herein the synthesis of cytotoxic cyanobactin, Wewakazole B through an efficient solution-phase approach. The key steps of the synthesis are the macrocyclic lactamization of linear dodecapeptide and construction of two hexapeptides with three different substituted oxazole rings.     

Isostructural neo-pentoxide derivatives of group 3 and the lanthanide series metals for the production of Ln2O3 nanoparticles

The synthesis and characterization of a series of neo-pentoxide (OCH2C(CH3)3 or ONep) derivatives of group 3 and the lanthanide (Ln) series' metals were undertaken via an amide/alcohol exchange route. Surprisingly, the products isolated and characterized by single-crystal X-ray diffraction yielded isostructural species for every trivalent cation studied: [Ln(mu-ONep)2(ONep)]4 [Ln=Sc (1), Y (2), La (3), Ce (4), Pr (5), Nd (6), Sm (7), Eu (8), Gd (9), Tb (10), Dy (11), Ho (12), Er (13), Tm (14), Yb (15), Lu (16)]. Compounds 3, 4, 6, and 11 have been previously reported. Within this series of complexes, the Ln metal centers are oriented in a square with each Ln-Ln edge interconnected via two mu-ONep ligands; each metal center also binds one terminal ONep ligand. NMR data of 1-3 indicate that the solid-state structure is retained in solution. FTIR spectroscopy (KBr pellet) revealed the presence of significant Ln---H-C interactions within one set of the bridging ONep ligands in all cases; the stretching frequencies of these C-H bonds appear to increase in magnitude with decrease in metal ion radius. These complexes were used to generate nanoparticles through solution hydrolysis routes, resulting in the formation of lanthanide oxide nanoparticles and rods. The emission properties of these ceramics were preliminarily investigated using UV-vis and PL measurements.