Computer simulation of human head irradiation by a cell phone field

Communication systems are developing at an incredible speed. This also applies to mobile communication systems, which today are among the most important telecommunication systems operating at microwave frequencies. Working mobile phones are sources of non-ionizing radiation near the head or body. Despite the fact that the average person spends several conversations on a cell phone every day, the issue of the impact of radiation on health has not yet been fully studied. Simulate the effect of cell phone radiation on biological tissues of the human body, in particular on the head. Two computer models of the human head have been built. Computer simulation of the effect of cell phone radiation on biological tissues of the human body has been performed. An important feature of the model is the presence of layers with different parameters. The layers correspond to real biological tissues (skin, adipose tissue, muscle, skull and brain). A study of the field distribution in the volume of the human head, induced by a working mobile phone, is presented. The specific absorption coefficient was determined. Shown is the thermal effect caused by exposure to radiation from a mobile phone. In the case of the multilayer model, lower values of the specific absorption coefficient were obtained, which can be explained by the use of a more accurate computer model. It became possible to graphically represent the propagation of electromagnetic waves through the head model. The temperature distribution over the surface and in the volume of the human head is illustrated.

The color of EPEA: Variability in the in situ bio-optical properties in the period 2000 - 2017

The “Estación Permanente de Estudios Ambientales” (EPEA, 38°28´ S 57°41´ W, Argentina) is an ecological time series of in situ observations started in 2000 aiming to assess changes in the marine environment and plankton communities under a global change scenario. Bio-optical properties are studied at EPEA since the color of the ocean undergoes temporal fluctuations, both for natural and anthropogenic causes. Here we assessed whether bio-optical properties at EPEA have changed during 2000-2017, identifying the occurrence of special events and inter-annual trends in these properties. An increasing trend in chlorophyll a concentration, possibly due to an increase in the smaller fraction of phytoplankton was observed. Although the absorption coefficient of phytoplankton did not follow a significant trend, it represented the occurrence of special events of high biomass suggesting that satellite information should be useful for the study site. The specific absorption coefficient of phytoplankton and the blue to red absorption ratio showed high values in summer and low in winter, according to the probable dominance of different size cells and their expected acclimation to the light regime. These results emphasize the relevance of periodic bio-optical in situ observations in understanding coastal ecosystems in a context of climate change.

A STUDY OF THE ANTIOXIDANT ACTIVITY OF PLANTS OF THE GENUS POTENTILLA L.

In this work, a comparative assessment of the antiradical properties of some species of the genus Potentilla L. is carried out to identify the most promising in terms of further study. The aboveground part of P. chrysantha Trevir., P. canescens Bess., P. tergemina Sojak, P. erecta (L.) Raeusch., P. paradoxa Nutt. ex Tott. et Gray, P. approximata Bunge, as well as the aboveground and underground parts of P. anserina L. were used as a research object, collected in the vicinity of Tomsk. The antiradical activity of the extracts of the studied plants was evaluated spectrophotometrically, observing the kinetics of the recovery of the stable radical of the DPPH extract. The dependence of the antiradical activity on the concentration and stability of the studied extracts was examined using P. paradoxa as an example. The total amount of phenolic compounds and flavonoids in the studied extracts was estimated. The specific absorption coefficient of gallic acid was found to be 47.3. For the aboveground parts of seven Potentilla species, the antiradical activity of extracts on ethyl alcohol 40 and 70% is significant and is in a narrow range from 77.57 to 80.91% for extracts on ethyl alcohol 40%, in a slightly wider range from 70.99 to 86.58% for extracts on ethyl alcohol 70%. A wide range of antiradical activity from 14.80% (P. tergemina) to 70.40% (P. paradoxa) is observed for 95% ethyl alcohol extracts. The difference in the chemical composition of ethanol extracts of individual representatives of the genus Potentilla significantly affects the antiradical activity with an increase in the concentration of ethyl alcohol.