The cell Reynolds number myth

The commonly accepted linear stability analysis for the forward-time centred-space (FTCS) algorithm applied to the transport equation has led to the concept of a cell Reynolds number restriction on the spatial grid size. This paper shows where the commonly accepted original analysis is in error and presents the correct stability restrictions, which are restrictions on the time step, not the spatial grid size. There is no cell Reynolds number restriction. The results are confirmed by numerical computations for the two-dimensional driven cavity problem.     

Some INDO calculations of the dependence of one-bond phosphorus-phosphorus coupling upon molecular geometry

Some INDO parameterized SCPT calculations of ¹J(P? P) and ¹J(P?P) are reported as a function of geometry. At structures corresponding to the gas-phase equilibrium configuration of diphosphine, all of the substituted diphosphines considered are predicted to have negative values of ¹J(P? P). Both contact and non-contact contributions to ¹J(P? P) are significant, whereas the angular variation of ¹J(P? P) is mainly due to the contact term. The non-contact interactions are dominant in determining the value of ¹J(P?P).     

Nitrogen and carbon NMR of some benzofuroxans

¹⁵N and ¹⁴N NMR spectra show that there is no valence tautomerism involving the nitro group in nitro derivatives of benzofuroxan systems and that the N-oxide function has a fixed position in the furoxan ring. Carbon chemical shifts of molecules with one, two or three furoxan rings attached to a benzene ring reveal additivity of effects which makes possible a complete and unambiguous assignment of the shifts.     

A study of factors affecting the InSb c.w. spin-flip Raman laser

The behaviour of the c.w. spin-flip Raman laser is quantified by comparing its operation in the regimes of pump depletion and spin-saturation using InSb samples of different electron concentrations. The use of such a system for wide range spectroscopic applications, complementary to its narrow linewidth characteristic, is indicated.     

Calculation of some nitrogen nuclear screening constants

Some nitrogen screening constants and their anisotropies are calculated within the CNDO/S level of approximation. Satisfactory agreement is found with available experimental data in most cases. In general the reported results are in closer agreement with experiment than are those found from ab initio calculations. The calculated data for the isoelectronic molecules N₂O and CH₂N₂ would be in better agreement with experiment if the assignments of the two nitrogen nuclei were reversed in both cases. A reasonable correlation is obtained with some observed nitrogen chemical shifts. Contributions arising from electronic transitions are reported for N₂, HCN, CH₃CN, CH₃NC, NO₂⁺ and NO₂^?.     

Nonlinear perturbations of linear accretive operators in Banach spaces

It is shown that a strongly continuous semi-group of nonlinear nonexpansive operators can be constructed as lim _n→∞ ((I+t/nB)⁻¹ (I+t/nB)⁻¹) ⁿ whereA is a linearm-accretive operator,B is a nonlinearm-accretive operator, andB satisfies a boundedness condition relative toA.     

Functional GPCR microarrays

This paper describes G-protein-coupled receptor (GPCR) microarrays on porous glass substrates and functional assays based on the binding of a europium-labeled GTP analogue. The porous glass slides were made by casting a glass frit on impermeable glass slides and then coating with gamma-aminopropyl silane (GAPS). The emitted fluorescence was captured on an imager with a time-gated intensified CCD detector. Microarrays of the neurotensin receptor 1, the cholinergic receptor muscarinic 2, the opioid receptor mu, and the cannabinoid receptor 1 were fabricated by pin printing. The selective agonism of each of the receptors was observed. The screening of potential antagonists was demonstrated using a cocktail of agonists. The amount of activation observed was sufficient to permit determinations of EC50 and IC50. Such microarrays could potentially streamline drug discovery by helping integrate primary screening with selectivity and safety screening without compromising the essential functional information obtainable from cellular assays.     

INDO calculations of the solvent dependence of some spin–spin couplings of fluorocarbons

The results of some SCPT and SOS calculations of ¹J(CH), ¹J(FC), ²J(FH), ³J(FH), ³J(FF) and ¹J(CC) in a variety of solvents are reported. The calculations employ the solvaton model and INDO parameters. In almost all cases the coupling is predicted to increase as the dielectric constant of the solvent increases, the exception being ³J(FH)cis in trifluoroethylene which is supported by experimental results.