Action spectra affect variability of the climatology of biologically effective ultraviolet radiation on cloud-free days.

Action spectrum (AS) describes the relative effectiveness of ultraviolet (UV) radiation in producing biological effects and allows spectral UV irradiance to be weighted in order to compute biologically effective UV radiation (UVBE). The aim of this research was to study the seasonal and latitudinal distribution over Europe of daily UVBE doses responsible for various biological effects on humans and plants. Clear sky UV radiation spectra were computed at 30-min time intervals for the first day of each month of the year for Rome, Potsdam and Trondheim using a radiative transfer model fed with climatological data. Spectral data were weighted using AS for erythema, vitamin D synthesis, cataract and photokeratitis for humans, while the generalised plant damage and the plant damage AS were used for plants. The daily UVBE doses for the above-mentioned biological processes were computed and are analysed in this study. The patterns of variation due to season (for each location) and latitude (for each date) resulted as being specific for each adopted AS. The biological implications of these results are briefly discussed highlighting the importance of a specific UVBE climatology for each biological process.

The influence of climate on durum wheat quality in Tuscany, Central Italy.

Climate and meteorological conditions greatly affect agricultural activities, modifying plant responses and determining the quantity and the quality of production. In this respect, the aim of this research was to analyze the quality of winter durum wheat (Triticum turgidum L. var. durum), in terms of protein content through the use of meteorological information. Meteorological conditions were described utilizing both local weather station data (air temperature, cumulated precipitation) and large-scale information available freely on the internet, such as geopotential height (GPH), sea surface temperature (SST), and the North Atlantic Oscillation (NAO) index. The analysis was carried out for the period 1997-2009 in the Tuscany region, Central Italy. Grain protein was positively correlated with air temperature during the February to June period, and negatively with cumulative precipitation during the entire period from November to June. Protein content was also negatively correlated with 500 hPa GPH over Gibraltar and North-Western Africa during the March to June period and with the SST of the Atlantic Ocean south-west of the Canary Islands during the January to June period. Finally, with regard to the NAO, winter durum wheat quality was positively correlated with the specific index for several months, in particular during the winter period. These results demonstrate that precipitation and air temperature over the production area represent two crucial variables driving the vegeto-productive responses of winter durum wheat. On the other hand, the use of large-scale meteorological information showed great potential from the perspective of a local quality forecast system setup.

Row orientation effect on UV-B, UV-A and PAR solar irradiation components in vineyards at Tuscany, Italy.

Besides playing an essential role in plant photosynthesis, solar radiation is also involved in many other important biological processes. In particular, it has been demonstrated that ultraviolet (UV) solar radiation plays a relevant role in grapevines (Vitis vinifera) in the production of certain important chemical compounds directly responsible for yield and wine quality. Moreover, the exposure to UV-B radiation (280-320 nm) can affect plant-disease interaction by influencing the behaviour of both pathogen and host. The main objective of this research was to characterise the solar radiative regime of a vineyard, in terms of photosynthetically active radiation (PAR) and UV components. In this analysis, solar spectral UV irradiance components, broadband UV (280-400 nm), spectral UV-B and UV-A (320-400 nm), the biological effective UVBE, as well as the PAR (400-700 nm) component, were all considered. The diurnal patterns of these quantities and the UV-B/PAR and UV-B/UV-A ratios were analysed to investigate the effect of row orientation of the vineyard in combination with solar azimuth and elevation angles. The distribution of PAR and UV irradiance at various heights of the vertical sides of the rows was also studied. The results showed that the highest portion of plants received higher levels of daily radiation, especially the UV-B component. Row orientation of the vines had a pronounced effect on the global PAR received by the two sides of the rows and, to a lesser extent, UV-A and UV-B. When only the diffused component was considered, this geometrical effect was greatly attenuated. UV-B/PAR and UV-A/PAR ratios were also affected, with potential consequences on physiological processes. Because of the high diffusive capacity of the UV-B radiation, the UV-B/PAR ratio was significantly lower on the plant portions exposed to full sunlight than on those in the shade.

UV hazard on a summer's day under Mediterranean conditions, and the protective role of a beach umbrella.

Mediterranean beaches are very crowded during summer and, because of the high values of solar UV radiation, the potential risk for human health is relevant. In this study, all-day measurements of biologically effective global and diffuse UV radiation for skin (UVBE(eryt)) and eye (UVBE(pker), UVBE(pconj), UVBE(cat)) disorders were carried out on differently tilted surfaces on a summer's day on a Mediterranean beach. The role played by beach umbrellas in protection from excessive sun exposure was also investigated. Erythema, photokeratitis and cataract seem to require almost the same exposure time to reach the risk threshold dose. Under full sunlight, the highest global and diffuse UV values are reached on surfaces normally oriented towards sunlight and on horizontal surfaces, respectively. Over vertical surfaces, at this northern hemisphere site, global and diffuse UV radiation reaches maxima values in the south-facing direction around noon, while maxima values are reached early in the morning and late in the afternoon over surfaces facing east and west, respectively. The quality of the beach umbrella's protection (efficiency in blocking solar UV radiation) varies with surface orientation; the highest efficiency for our specific site and geometrical conditions occurs over horizontal surfaces, with efficiency being least over vertical surfaces when incident radiation values are still relevant.

Arginine 2-mercaptoethane sulfonate and sodium 2-mercaptoethane sulfonate: a comparative study of their effects upon tumour cells.

The action of arginine 2-mercaptoethane sulfonate in comparison with sodium 2-mercaptoethane sulfonate on cell growth and cell adhesion of a metastatic sub-line of murine melanoma (F10/B16) was investigated. The capability of the two compounds to interfere with the cytotoxicity of 4-hydroperoxycyclophosphamide and of cis-dichlorodiammineplatinum(II) in F10 cells was studied. The in vivo studies included the determination of acute and sub-acute toxicity of the two salts on mice. Very low toxicity and no significant differences between the two compounds were detected.