J.A. Martinez-Lozano

Bio: J.A. Martinez-Lozano is an academic researcher. The author has contributed to research in topics: Pyranometer & Ultraviolet index. The author has an hindex of 1, co-authored 2 publications receiving 4 citations.

A preliminary estimation of the direct ultraviolet spectral irradiance in Valencia (Spain) : Comparison with measured values

Abstract: UVSPEC and SMARTS2 models have been used to estimate the UV spectral irradiance values in Valencia, Spain, and the results of these estimations have been compared with experimental measurements of direct irradiance at normal incidence obtained using an Optronic OL 754 in the 300-400 nm range. The relative RMSD and MBD parameters have been used to estimate the deviations of the modelled values with respect to the experimental values. The results indicate that the deviations are smaller when the SMARTS2 model is used with the appropriate aerosol coefficients.

Spectral and Broad Band Ultraviolet Measurements in Valencia (Spain): A Preliminary Comparison

Abstract: The Solar Radiation Group of the University of Valencia, in collaboration with the National Institute of Meteorology (INM), recently began a database of erythemal UV irradiance measurements. Such measurements are obtained by a YES UVB-1 pyranometer (280-330 nm) that measures continuously, integrates the values and stores them in a database. The measured values are being compared with those obtained by the integration of the data registered by an Optronic OL 754 spectroradiometer (250-800 nm) considering clear days and different solar zenith angles. For the present study only the data corresponding to the summer (1999) are being considered because these are the days of the year with the higher erythemal values and also the season when people enjoy sunbathing. The results are used to deduce the ultraviolet index (UVI) related to the erythemal doses and the sunburn time.

UV Index Experimental Values During the Years 2000 and 2001 from the Spanish Broadband UV‐B Radiometric Network¶

Abstract: An analysis is made of experimental ultraviolet erythemal solar radiation data measured during the years 2000 and 2001 by the Spanish UV-B radiation evaluation and prediction network This network consists of 16 Robertson-Berger type pyranometers for evaluating solar erythemal radiation and five Brewer spectroradiometers for evaluating the stratospheric ozone On the basis of these data the Ultraviolet Index (UVI) was evaluated for the measuring stations that are located either in coastal regions or in the more densely populated regions inland on the Iberian Peninsula It has been checked that in most cases the maximum irradiance values corresponded to solar noon, although there were exceptions that could be explained by cloudiness The maximum experimental values of the UVI were around 9 during the summer, though frequently passing this value at the inland measurement stations The annual accumulated dose of irradiation on a horizontal plane has also been studied, as well as the evolution through the year in units of energy, standard erythemal doses and minimum erythemal doses, according to different phototypes

Spectral transmission of the pig lens: effect of ultraviolet A+B radiation.

Abstract: Summary Objective To determine the spectral transmission curve of the crystalline lens of the pig. To analyse how this curve changes when the crystalline lens is irradiated with ultraviolet A + B radiation similar to that of the sun. To compare these results with literature data from the human crystalline lens. Procedures We used crystalline lenses of the common pig from a slaughterhouse, i.e. genetically similar pigs, fed with the same diet, and slaughtered at six months old. Spectral transmission was measured with a Perkin-Elmer Lambda 35 UV/VIS spectrometer. The lenses were irradiated using an Asahi Spectra Lax-C100 ultraviolet source, which made it possible to select the spectral emission band as well as the intensity and exposure time. Results The pig lens transmits all the visible spectrum (95%) and lets part of the ultraviolet A through (15%). Exposure to acute UV (A + B) irradiation causes a decrease in its transmission as the intensity or exposure time increases: this decrease is considerable in the UV region. Conclusions We were able to determine the mean spectral transmission curve of the pig lens. It appears to be similar to that of the human lens in the visible spectrum, but different in the ultraviolet. Pig lens transmission is reduced by UV (A + B) irradiation and its transmission in the UV region can even disappear as the intensity or exposure time increases. An adequate exposure intensity and time of UV (A + B) radiation always causes an anterior subcapsular cataract (ASC).

Ultraviolet radiation at Mediterranean latitudes and protection efficacy of intraocular lenses.

Abstract: Summary Purpose After determining the mean intensity of ultraviolet radiation to which the human eye is exposed at Mediterranean latitudes, this data is used to evaluate the efficacy of the ultraviolet filters incorporated into various intraocular lenses. Methods Ultraviolet radiation measured at Mediterranean latitudes was used as a reference for the theoretical calculation of the amount of radiation to which the human eye is exposed. The spectral transmission curve from 290 to 380 nm was measured for 10 IOLs using a UV/VIS Perkins-Elmer Lambda 800 spectrometer. Results At Mediterranean latitudes, at sea level, with a mean annual solar irradiation of 50 j/cm 2 , the human eye receives a quantity of UVA and UVB that is lower than the threshold toxic dose for the rabbit crystalline lens (93 j/cm 2 for UVA and 6.45 j/cm 2 for UVB). However, at higher altitudes and with albedo approaching 0.9 (fresh snow), the amount of radiation increases, with duration of exposure potentially playing a significant role. The UV filters incorporated into the IOLs studied are, in general, protective against such levels of radiation. Conclusion At Mediterranean latitudes, at sea level, the amount of UV radiation to which our eyes are exposed is insufficient to damage the crystalline lens; however, at higher altitudes, the risk of such damage exists. UV filters incorporated into intraocular lenses are generally effective, since they filter all radiation with wavelengths under 380 nm.