Evolution Strategy Optimization for Selective Pulses in NMR

MUSIC and Aromatic Residues: Amino Acid Type-Selective 1H–15N Correlations, III

“…Self-refocusing L0S2-0 pulses (18,19) which affect only aromatic C γ carbons are used. This selection requires relatively long selective pulses.…”

Evolution Strategy Optimization for Adiabatic Pulses in MRI

“…We applied the sequence of Fig. 3, where the pulse to be tested is followed by the negative-phase 90°pulse L-3S4 (16,19), with a much larger bandwidth (12.5 kHz). At the end of the acquisition we make a Fourier transform and subtract from the absorption component the corresponding spectrum obtained without the first pulse.…”

“…To find the minimum of the cost function in the parameter space, we use a stochastic, evolution strategy algorithm (16), in which a "parent" solution p generates a "son" x with a probability density [14] the dispersion d is increased when lots of improvements arise (far from a solution) and decreased otherwise (near a solution).…”

“…The other ingredients of the method we propose are a robust stochastic optimizer, successfully used to obtain other types of selective pulses (16), and the choice of the "function spaces" where the search is performed. We have tried several approaches, including linear combinations of "promising" functions, and we have found the best results with functions which generalize the idea behind the hyperbolic secant (HS) pulse.…”

Dynamic NMR: combined use of 1D selective EXSY and complete lineshape analysis of spectra subjected to reference deconvolution and linear prediction or the maximum entropy method

“…27 -29 A number of new selective pulses for excitation, saturation and inversion have recently been designed. 30 An important point in choosing the type of pulse is its duration at a given selectivity. This will influence the magnetization that is left at the end of the pulse sequence.…”