Biomedical subjects

G R Casale

Publications and source records attributed to G R Casale.

4 recordsLinked to original sources

PubMed2006

Variability among polysulphone calibration curves.

Within an epidemiological study regarding the correlation between skin pathologies and personal ultraviolet (UV) exposure due to solar radiation, 14 field campaigns using polysulphone (PS) dosemeters were carried out at three different Italian sites (urban, semi-rural and rural) in every season of the year. A polysulphone calibration curve for each field experiment was obtained by measuring the ambient UV dose under almost clear sky conditions and the corresponding change in the PS film absorbance, prior and post exposure. Ambient UV doses were measured by well-calibrated broad-band radiometers and by electronic dosemeters. The dose-response relation was represented by the typical best fit to a third-degree polynomial and it was parameterized by a coefficient multiplying a cubic polynomial function. It was observed that the fit curves differed from each other in the coefficient only. It was assessed that the multiplying coefficient was affected by the solar UV spectrum at the Earth's surface whilst the polynomial factor depended on the photoinduced reaction of the polysulphone film. The mismatch between the polysulphone spectral curve and the CIE erythemal action spectrum was responsible for the variability among polysulphone calibration curves. The variability of the coefficient was related to the total ozone amount and the solar zenith angle. A mathematical explanation of such a parameterization was also discussed.

Biocompatible Materials↗

PubMed2006

A canopy layer model and its application to Rome.

An urban canopy layer model based on four energy balance equations at ground level and at building level was developed to simulate and describe the urban climate and the heat storage in an urban setting. Thermal and radiative characteristics of urban and rural surfaces as well as atmospheric parameters related to the general synoptic conditions were used as data input. In addition, buildings were modelled as parallelepipeds and the hysteresis of materials was taken into account. The model provides as output skin temperature of buildings, air temperature and humidity within the canopy layer and hence the mean surface temperature and the air temperature at 2 m above surface. The latter parameter was used for the comparison with in situ temperature observations. The model was applied to Rome in radiative summer and winter episodes. The results, which agree with observations, show that the Urban Heat Island (UHI) is a nocturnal phenomenon, present both in winter (the greatest difference between urban and rural temperatures is about 2 degrees C) and summer (the temperature difference is about 5 degrees C), mainly resulting from the urban geometry and the thermal properties of materials. The anthropogenic heat does not play an important role in the UHI development. A monthly nocturnal behaviour of temperature differences between urban and surrounding rural areas shows that the maximum mean value of 4.2 degrees C occurs in August. Moreover, the parks in the city centre, where temperatures are lower, define two distinct heat islands, east and west.

Air Pollution↗

PubMed2002

Spectral ultraviolet measurements by a multichannel monitor and a brewer spectroradiometer: a field study.

Two different instruments for measuring the spectral UV irradiance were used in a field comparison study in July 2000 in Rome, Italy: a Brewer spectrophotometer and a moderate-bandwidth filter radiometer (GUV-511C). The Brewer is designed to measure the solar spectral irradiances in the region from 290 nm to 325 nm with a spectral resolution of 0.5 nm. The GUV-511C measures hand-averaged spectral irradiance at four wavelengths: 305, 320, 340 and 380 nm with a bandwidth depending on the filter type for each channel (about 10 nm full width half maximum, FWHM). Comparisons between the two instruments were made for 5 days for the two wavelengths 305 and 320 nm under different meteorological conditions with the Brewer taken as the reference.

Equipment Failure Analysis↗

PubMed2000

Solar UV dose patterns in Italy.

Since 1992 solar ultraviolet (UV) spectral irradiance (290-325 nm) has been measured at two Italian stations of Rome (urban site) and Ispra (semirural site) using Brewer spectrophotometry. The data collected under all sky conditions, are compared with the output of a sophisticated radiative transfer model (System for Transfer of Atmospheric Radiation--STAR model). The STAR multiple scattering scheme is able to cope with all physical processes relevant to the UV transfer through the atmosphere. The experience so far acquired indicates that, in spite of the unavoidable uncertainties in the input parameters (ozone, aerosol, surface albedo, pressure, temperature, relative humidity, cloud cover), measured and computed clear sky iradiances are in reasonable agreement. The STAR model is applied to build up the solar UV geographic patterns in Italy: the daily dose in the range 290-325 nm is computed at about 70 sites where a thorough and homogeneous climatology is available. For each month the concept of an idealized "standard day" is introduced and the surface distribution of solar UV field determined. The map of solar UV patterns for Italy, available for the first time, meets the study requirements in the field of skin and eye epidemiology, as well as in other investigations dealing with the impact of UV on the biosphere. The results are interpreted in terms of atmospheric and meteorological parameters modulating UV radiation reaching the ground.

Eye↗