Comparative study of tunable room-temperature laser operation in the 900-1100-nm range: LiF:F2+ and Ti3+:sapphire.

We report on a comparative evaluation of efficient room-temperature solid-state lasers based on Ti:sapphire and LiF:F(2)(+) operating in the 900-1100-nm range. LiF:F(2)(+) lasers are shown to operate with substantially lower threshold, broader tuning, and higher output pulse energies. The shorter fluorescence lifetime in LiF:F(2)(+) leads to higher peak output powers and a considerable reduction in buildup-time fluctuations.

Use of texture analysis to discriminate between normal livers and livers with steatosis.

We describe a technique for discriminating between livers that are normal and ones that have fatty infiltrate (livers with steatosis) based upon the application of a suitably defined texture measure to the corresponding digitized ultrasonographs. In brief, this texture measure sums, from some selected optimum spatial frequency to the upper limit set by the digitizing process, the frequency components of the normalized, radial power spectral density function. The analysis was run on six cases (two normal and four with steatosis) obtained from Dunedin Public Hospital, in New Zealand.