Antisense peptide interactions studied by electrospray ionization mass spectrometry

Non-covalent interactions between met- and leu-enkephalins and their antisense peptides were studied by electrospray ionization mass spectrometry. Mixtures of sense and antisense peptides gave both the corresponding homodimers and heterodimers. The relative abundance ratios of the heterodimer to that of the homodimer of the sense peptide and the relative stability constants of the heterodimers were compared with the corresponding values from mixtures of the sense peptides and a control peptide. The results show that there is a preferential interaction between the sense and antisense peptides compared with that between the sense and control peptides.     

Fixed angular momentum moments and level densities

Approximate fixed-J energy moments are evaluated by orthogonal polynomial expansion and parametric derivative methods. Comparisons with exact values, both directly in terms of moments and in terms of level densities calculated from energy moments, show that sufficiently accurate values can be calculated to produce good fixed-J level densities.     

Innovative reconsolidation of carbon steel machining swarf by laser metal deposition

The concept of widespread recycling of metals in order to save cost, energy and ecological damage is gaining importance and this necessitates not simply disposing of machining waste. In this work a new way of reconstituting chips/swarf into a usable solid structure is explored by using them in place of metal powder in laser direct metal deposition. Samples of carbon steel machining swarf in three size ranges are reconstituted and the final structural characteristics like clad dimension, microstructure and physical properties are analysed. The results show that it is possible to reproduce a material that has full density, fine microstructure and no significant contamination from an unprecedented size and shape of particles. As general trends, individual deposition tracks become lower, wider and less hard as particle size increases. This work shows that the laser deposition process can be used with a larger range of particle geometries than previously considered and this could be the point leading to a new ‘local’ recycling method.     

fac-Cobalt(III)-azido complexes derived from substituted pyridyl-based tridentate amines

Four new mononuclear triazido-cobalt(III) complexes [Co(L ^1/2/4 )(N₃)₃] and [Co(L ³ )(N₃)₃]·CH₃CN where L ¹  = [(2-pyridyl)-2-ethyl]-(2-pyridylmethyl)-N-methylamine, L ²  = [(2-pyridyl)-2-ethyl]-[6-methyl-(2-pyridylmethyl)]-N-methylamine, L ³  = [(2-pyridyl)-2-ethyl]-[3,5-dimethyl-4-methoxy-(2-pyridylmethyl)]-N-methylamine, and L ⁴  = [(2-pyridyl)-2-ethyl]-[3,4-dimethoxy-(2-pyridylmethyl)]-N-methylamine, respectively, were synthesized and structurally characterized. The four complexes were characterized by elemental microanalyses, IR and UV–VIS spectroscopy and X-ray single crystal crystallography. The complexes display two strong IR bands over the frequency region 2,020–2,050 cm^?1 assigned for the asymmetric stretching frequency, ν_a(N₃) of the coordinated azides indicating facial geometry. The molecular structure determinations of the complexes were in complete agreement with fac-[Co(L)(N₃)₃] conformation in distorted octahedral Co(III) environment.     

Oscillator strengths of the 4s4p~^{{\mathsf{1,3}}}P1↦ 4snd~^{\mathsf {1,3}}D2 transitions of neutral calcium

A detailed study has been performed for estimating the orbital energies, positions and shifts of the Lyman lines of C⁵⁺, Al¹²⁺ and Ar¹⁷⁺ under strongly coupled plasma with a view to understand such line positions and shifts obtained in laser produced plasma experiments. The effect of strongly coupled plasma has been treated within the Ion Sphere (IS) model. Both non-relativistic and relativistic methods have been used for estimating the spectral properties. Theoretical estimates with IS model of the plasma are in conformity with the results of laser plasma experiments on these highly stripped ions. The experimental data for the systems have also been compared with the theoretical estimates using Debye screening model of the plasma with spatial confinements which gives additional restrictions to the wave functions at finite boundaries.