Impact of transition from microscopy to molecular screening for detection of intestinal protozoa in Dutch patients.

Detection of intestinal protozoa by PCR methods has been described as being sensitive and specific, and as improving the diagnostic yield. Here we present the outcome of the transition from microscopy to molecular screening for detection of a select group of intestinal protozoa in faeces in our laboratory. Introduction of molecular screening for intestinal protozoa resulted in higher sensitivity, reduced hands-on-time, reduced time-to-results, leading to improved diagnostic efficiency.

Stochastic electromagnetic radiation of complex sources.

The emission of electromagnetic radiation by localized complex electric charge and current distributions is studied. A statistical formalism in terms of general dynamical multipole fields is developed. The appearing coefficients are treated as stochastic variables. Hereby as much as possible a priori physical knowledge is exploited. First results of simulated statistical electromagnetic fields as a function of position are presented. Sampling this field at one point approximates its resulting probability density.

Cavity-Ring-Down Spectroscopy on Water Vapor in the Range 555-604 nm.

The method of pulsed cavity-ring-down spectroscopy was employed to record the water vapor absorption spectrum in the wavelength range 555-604 nm. The spectrum consists of 1830 lines, calibrated against the iodine standard with an accuracy of 0.01 cm(-1); 800 of these lines are not obtained in the HITRAN 96 database, while 243 are not included in the newly recorded Fourier transform spectrum of the Reims group. Of the set of hitherto unobserved lines, 111 could be given an assignment in terms of rovibrational quantum numbers from a comparison with first principles calculations. Copyright 2001 Academic Press.

Quantitative analysis of decay transients applied to a multimode pulsed cavity ringdown experiment.

The intensity and noise properties of decay transients obtained in a generic pulsed cavity ringdown experiment are analyzed experimentally and theoretically. A weighted nonlinear least-squares analysis of digitized decay transients is shown that avoids baseline offset effects that induce systematic deviations in the estimation of decay rates. As follows from simulations not only is it a method that provides correct estimates for the values of the fit parameters, but moreover it also yields a correct estimate of the precision of the fit parameters. It is shown experimentally that a properly aligned stable optical resonator can effectively yield monoexponential decays under multimode excitation. An on-line method has been developed, based on a statistical analysis of the noise properties of the decay transients, to align a stable resonator toward this monoexponential decay.

Experimental verification of Rayleigh scattering cross sections.

The cavity-ringdown technique is applied to measure Rayleigh extinctions of Ar, N(2), and SF(6) in the 560-650-nm region at 294 K. It is shown that experimental and calculated Rayleigh scattering cross sections agree within an experimental uncertainty of 1% (for SF(6), 3%).

Visible absorption bands of the (O2)2 collision complex at pressures below 760 Torr.

The collision-induced absorption of oxygen in the 540-650-nm wavelength region has been measured ata pressure range from 0 to 730 Torr at T 5 294 K. Pressure-dependent cross sections of the X 3Sigmag(+)+X 3Sigmag alpha 1Deltag(nu =0) + alpha 1Deltag(nu = 1 ) and X 3Simag(+)+ X 3Sigmag+--> alpha 1Deltag(nu =0) + 1 alpha 1Deltag (nu = 0) transitions have been determined by means of cavity-ringdown spectroscopy. Contributions of the overlapping g and d bands of O2 have been evaded, and Rayleigh extinction has been taken into account.

Cavity-Ring-Down Spectroscopy on the b1Sigma+g-X3Sigma-g (1,0) Band of Oxygen Isotopomers.

The b1Sigma+g-X3Sigma-g (1,0) band of 16O17O, 16O18O, 18O2, 17O18O, and 17O2 isotopomers was investigated employing the technique of cavity-ring-down spectroscopy. More than 400 transition frequencies of magnetic dipole lines were determined with a typical uncertainty of 0.01 cm-1. This work results in new or improved accurate molecular constants for the excited b1Sigma+g, v = 1 state of all isotopomers and for the X3Sigma-g, v = 0 ground state of 17O2. Copyright 1998 Academic Press.