ABSTRACT
We have measured terahertz near-field spectra of cesium iodide crystals as small as ~10 µm in diameter, which were deposited on single, sub-wavelength-sized apertures created in thin gold films on a substrate. The advantage of using small apertures for terahertz microspectroscopy is that only terahertz light that has interacted with the cesium iodide is observed. We find that around the transverse optical phonon frequency of cesium iodide, the amplitude transmission is as much influenced by the refractive index as by the absorption. We show that the ability to measure in the near-field of the apertures, where signals are relatively strong, allows us to measure on sample volumes as small as ~5×10(-16) m(3).
ABSTRACT
A limiting factor in using microporous capillary membrane oxygenators (CMO) for long-term extracorporeal lung support is leakage. Application of heparin-coated CMO requires additional examination because leakage is probably caused by the temperature conditions of the gas, the blood and the circuit environment, and the surface tension phenomenon at the micropores. The authors designed a thermostatized box in which the temperature of flowing gas (Tg) and blood (Tb), and the interior temperature of the box (Ti) could be regulated independently. Tb was adjusted to the animal's body temperature, and Tg was kept about 2 degrees C higher to prevent condensation of the evaporated fluid from the blood side, through the micropores, into the gas phase. Ti was maintained between Tg and Tb. The saturated outlet gas could therefore condense only outside the box. This system was used during 5 days of venovenous bypass using a covalently heparin-bonded (Carmeda) CMO (Maxima, Medtronic) in four adult sheep. No plasma leakage occurred, the surface tension of condensate water remained constant, and the gas exchange capacity of CMO was unchanged.
