A relationship has been reported by several research groups [1 - 4] between the density and shapes of nerve fibers in the cornea and the existence and severity of peripheral neuropathy. Peripheral neuropathy is a complication of several prevalent diseases or conditions, which include diabetes, HIV, prolonged alcohol overconsumption and aging. A common clinical technique for confirming the condition is intramuscular electromyography (EMG), which is invasive, so a noninvasive technique like the one proposed here carries important potential advantages for the physician and patient.
A software program that automatically detects the nerve fibers, counts them and measures their shapes is being developed and tested. Tests were carried out with a database of subjects with levels of severity of diabetic neuropathy as determined by EMG testing. Results from this testing, that include a linear regression analysis are shown.
In the framework of the Radiation Explorer in the Far InfraRed space mission for the characterization in the far infrared of the Earth outgoing emission, a breadboard version of the Fourier transform spectrometer, which is the core instrument of the payload package, has been developed. The Fourier transform spectrometer operates in the spectral range of 100-1100 cm-1 with a resolution of 0.5 cm-1, 6.5 s acquisition time, and signal-to-noise ratio better than 100. It is a compact prototype designed both for laboratory applications and for field campaigns, in particular for operations in high-altitude ground-based sites and on-board of stratospheric balloon platforms.
This paper describes the instrument characterization performed in laboratory conditions and under vacuum. The study has allowed to study the trade-off among all the instrument parameters and to test the new optical design of the interferometer, with particular attention to the photolithographic beam splitters and the room-temperature pyroelectric detectors.
The instrument was operated for the first time in a field campaign in June 2004 from 1247~m altitude ground-based site located in the South of Italy. The results of this test and the comparison with the measurements taken with a BOMEM spectrometer, that partially overlaps the REFIR bandwidth in the higher spectral region, are reported. Info can be found at http://radiation.ifac.cnr.it.
Based on the evidence of the correlation between certain differential spectral parameters that can be estimated through attenuation measurements in the 18-22 GHz spectral range and the columnar content of atmospheric water vapor (IWV: Integrated Water Vapor), recently we pointed out that such correlation can be profitably exploited to provide direct estimates of the IWV along vertical Earth-satellite links, showing in particular that at 19 GHz a practically deterministic relationships holds between the IWV and such differential spectral parameters. In this paper we present some new simulation results to show that the parameters can be estimated by means of a 19 GHz CW-FM nadir pointing radar, providing in this way a continuous monitoring of the IWV along vertical atmospheric sections. Differential attenuation measurements are made by exploiting the backscatter from the Earth surface. Simulations, that are based on real vertical profiles of temperature, pressure and water vapor concentration as provided by a large radiosonde dataset, refer to a LEO satellite and to an airborne configuration, indicate the possibility to retrieve the IWV in both cases.