The synthesis of l-alkyl-2-benzoyl-4-methylazetidine. Configurational and conformational studies

α,γ-Dibromovalerophenone ( 3 ) reacted with primary amines to give a number of l-alkyl-2-benzoyl-4-methylazetidines ( 4 ) in good yield. The results of the base catalyzed reactions performed on these new carboazetidines imply that the cis isomer is of greater thermodynamic stability. Furthermore, base catalyzed deuterium exchange studies suggest this to be the case. J. Heterocyclic Chem., 14, 981 (1977)     

Two-beam modulation instability in noninstantaneous nonlinear media

The development of modulation instability for two beams copropagating in a medium with noninstantaneous nonlinear response is investigated. The frequency dependence of the experimentally observed spectral broadening reveals the presence of two-beam coupling, resulting from the time-delayed Raman part of the third-order nonlinear susceptibility. We present an analysis of the experimental data, which yields a value of tau=27(1) fs for the lifetime of the optical phonons in silica fibers. To our knowledge, this is the first experimentally determined value for this important material parameter.     

A study of the linear interpolation used in the analytical tetrahedron method

A test of the accuracy of the linear interpolation used in the analytical tetrahedron method has been carried out with the two different dispersion relations. It was found that although the interpolation is suitable for spectral functions, it is not reliable for quantitative study of the Fermi wavevectors and Fermi surface cross sections. Also a comparison with the star-averaged linear interpolation is made.     

Surface plasmon resonance

During last decade there has been significant progress in the development of analytical techniques for evaluation of receptor-ligand iteraction. Surface plasmon resonance (SPR)-based optical biosensors are now being used extensively to defined the kinetics of wide variety of macromolecular interactions and high- and low-affinity small molecule interactions. The experimental design data analysis methods are evolving along with widespread applications in ligand fishing, microbiology, virology, host-pathogen interaction, epitope mapping and protein-, cell-, membrane-, nucleic acid-protein interactions. SPR based biosensors have strong impact on basic and applied research significantly. This brief review describes the SPR technology and few of its applications in relation to receptor-ligand interaction that has brought significant change in the methodology, analysis, interpretation, and application of the SPR technology.     

An ICP-AES method for the determination of heavy rare earth elements (Eu-Lu) in high purity yttrium oxide

Traces of heavy rare earth elements (Eu-Lu) were determined in high purity yttrium oxide by inductively coupled plasma atomic emission spectrometry. The yttrium oxide samples were dissolved in nitric acid and the solutions analyzed with a plasma produced by a 56 MHz RF generator at an output power of 1.5 kW. Using a high resolution sequential monochromator, interference-free spectral lines for Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu could be found for calibration. The detection limits for the above elements have been found to be slightly higher in the presence of yttrium matrix, than in aqueous solution. This could be attributed to background enhancements due to the presence of yttrium. The mean RSD of the method varied between 2.3% and 6.3% in the concentration range 0.01 and 0.5 g/ml. The percentage recovery ranged from 84 to 106 for the different rare earth elements.     

Effect of quenching conditions on particle formation and growth in thermal plasma synthesis of fine powders

The vapor-phase synthesis of ultrafine powders in reactive thermal plasma systems is studied. A mathematical model is developed to determine the effect of quenching conditions on the size characteristics of powders produced. The particle nucleation is considered to be due to both condensation of product vapor and surface reaction between adsorbed reactant species. The particle growth is considered to be exclusively due to further condensation of product vapor. Numerical predictions on powder formation are explored through a case study for the synthesis of zinc oxide powders from zinc vapor and oxygen carried in argon gas. The results of the present srudy indicate that the size characteristics of plasma-produced powders can be significantly enhanced by gradual, regulated quenching, as opposed to the rapid quenching conventionally used in the past. The results further indicate that distribution of the quench gas along the reactor provides an effective means to accomplish the much desired control over the powder properties.     

Influence of phosphorylation on the foamability and stability of bovine serum albumin and citrus peel pectin mixed foams

We study the influence of phosphorylation on the foamability and stability of bovine serum albumin (BSA), phosphorylated BSA (pBSA), and citrus peel pectin (CPP) mixed foams as a function of BSA–CPP, pBSA–CPP mixing ratios, at a fixed solution pH of 4.5. Our results show that pBSA solutions result in more stable foams as compared with their BSA counterparts. We further show that the addition of CPP leads to BSA–CPP and pBSA–CPP complexation which increases the foamability and stability of foams as compared with protein-only foams. Also, foam stability is highest for pBSA–CPP mixed foams with mixing ratio pBSA:CPP?=?1:1 due to the combined effect of pBSA–pBSA and pBSA–CPP interactions.     

α‐RbO3, a Low Temperature Polymorph of Rubidium Ozonide

Applying the known procedure for synthesis of alkali metal ozonides, just at a lower temperature, has yielded a new polymorph of rubidium ozonide, α‐RbO₃ [P2₁; a = 436.3(2), b = 595.3(3), c = 548.7(3) pm, β = 99.680(7), R = 0.0400, 1184 reflections]. Like previously reported β‐RbO₃, the basic structural arrangement of anions and cations corresponds to the CsCl type of structure, however, the mutual orientation of the ozonide ions is different, in as much as one of the two terminal oxygen atoms is pointing to the adjacent bridging oxygen atom, forming a chain running along the b axis.     

Structure development during melt spinning and subsequent annealing of polybutene‐1 fibers

The structural development during the melt spinning and subsequent annealing of polybutene‐1 fibers was studied with in situ wide‐angle X‐ray scattering techniques. The online spinning apparatus consisted of a vertically translating extruder that allowed different distances from the spinneret to the stationary X‐ray beam to be sampled. For all take‐up speeds examined, phase II crystals mainly were formed, with only a small population of phase I crystals existing. As the take‐up speed was increased, the crystallinity also increased, indicating that strain‐induced crystallization prevailed. The crystalline orientations observed online were very close to perfect alignment with the fiber axis. In addition, annealing studies were performed to study aspects of the gradual phase II to phase I transformation as functions of time and prior processing take‐up speed. This transformation was strongly dependent on the take‐up speed. The dependence appears to be connected to local stress enhancement via chains connecting crystallites. The results also seem to indicate that at low take‐up speeds (17 mpm) there is a series connectivity of amorphous and crystalline components in the fiber, whereas at greater take‐up speeds (100 and 250 mpm), the morphology grows into some type of three‐dimensional network, possibly a shish–kebob‐type morphology. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1872–1882, 2000