RESUMO
Subtraction and ratioing of strong absorption bands in Fourier transform infrared (FT-IR) spectroscopy produces anomalous absorption errors. One source of error is the instability in the wavenumber scale of the FT-IR spectra. The possible causes of this error are explored. The thermal expansion and contraction of the cavity of the HeNe reference laser from a typical commercial instrument was found to produce changes in the laser wavenumber of ±0.034 cm(-)(1). Changes of this size are shown to introduce errors into the wavenumber scales of FT-IR spectra which are sufficient to produce the observed anomalies. The dependence of the error on instrumental and spectroscopic parameters is explored. Solutions to the problem are proposed.
RESUMO
A fatal case of chronic meningeal sporotrichosis occurring as an opportunistic infection in a patient with Hodgkin's disease is presented. A pulmonary source of infection was identified at autopsy. The diagnostic importance of the isolation of Sporothrix schenckii from cerebrospinal fluid, even if only from a single specimen, is stressed.
Assuntos
Doença de Hodgkin/complicações , Meningite/etiologia , Esporotricose , Exposição Ambiental , Humanos , Pneumopatias Fúngicas/complicações , Masculino , Pessoa de Meia-Idade , Sporothrix/isolamento & purificação , Esporotricose/diagnósticoRESUMO
Design and performance are given of a multiple traversal low temperature absorption cell that operates routinely at a path length of 230 m. The system is comprised of an f/30-aperture White cell surrounded by an aluminum Dewar. The cell has been used in the temperature range 300-77 K and may be pressurized to 3 atm. Vacuum feedthrough adjustments are employed in order to correct for defocusing of the mirrors during the cooling process.
