New Triterpenes from the Fungus Gloeophyllum odoratum

Two new triterpene acids (1, 2), together with a complex mixture of lecithins (3), were isolated from the fungus Gloeophyllum odoratum. Their structures were elucidated on the basis of extensive spectroscopic analyses. The extract of Gloeophyllum odoratum considerably inhibited thrombin (72% at a concentration of 120 g/mL); the less polar fraction of the methanolic extract from the mushroom exhibited interesting activity (47% at a concentration of 120 g/mL) against thrombin. Compounds 1 and 2 were responsible for this activity

Estimation of photovoltaic power generation potential in Serbia based on irradiance, air temperature, and wind speed data

This study is devoted to the research of spatial-temporal variation of electricity generation from the kilowatt-peak photovoltaic system made of crystalline silicon solar cells. The research was conducted in the territory of Serbia using the model for estimation photovoltaic performances as a function of incident irradiance and module temperature. Preparation of input data and calculation of the final results was done within the geographical information system. Some of the required raster data, like solar irradiance and wind speed, were already available, while air temperature raster was created from discrete set of observed data using the regression-kriging model. Obtained results were presented in the form of raster maps that enabled further analysis and discussion about new findings. The analysis of seasonal variations reveals that during spring and summer months photovoltaic systems are producing up to 70% of total annual electricity yield. In terms of the spatial distribution, the most promising areas for electricity generation are located in the south part of Serbia and along main river valleys. In addition, discussion part addresses the issue of data imperfection caused by the accuracy of the selected model, as well as quality and availability of data series

Prediction of tropospheric ozone concentration using artificial neural networks at traffic and background urban locations in Novi Sad, Serbia

In this paper, we described generation and performances of feedforward neural network model that could be used for a day ahead predictions of the daily maximum 1-h ozone concentration (1hO3) and 8-h average ozone concentration (8hO3) at one traffic and one background station in the urban area of Novi Sad, Serbia. The six meteorological variables for the day preceding the forecast and forecast day, ozone concentrations in the day preceding the forecast, the number of the day of the year, and the number of the weekday for which ozone prediction was performed were utilized as inputs. The three-layer perceptron neural network models with the best performance were chosen by testing with different numbers of neurons in the hidden layer and different activation functions. The mean bias error, mean absolute error, root mean squared error, correlation coefficient, and index of agreement or Willmott’s Index for the validation data for 1hO3 forecasting were 0.005 μg m−3, 12.149 μg m−3, 15.926 μg m−3, 0.988, and 0.950, respectively, for the traffic station (Dnevnik), and − 0.565 μg m−3, 10.101 μg m−3, 12.962 μg m−3, 0.911, and 0.953, respectively, for the background station (Liman). For 8hO3 forecasting, statistical indicators were − 1.126 μg m−3, 10.614 μg m−3, 12.962 μg m−3, 0.910, and 0.948 respectively for the station Dnevnik and − 0.001 μg m−3, 8.574 μg m−3, 10.741 μg m−3, 0.936, and 0.966, respectively, for the station Liman. According to the Kolmogorov–Smirnov test, there is no significant difference between measured and predicted data. Models showed a good performance in forecasting days with the high values over a certain threshold

Spatio-temporal varilability of annual PM 2.5 concentrations and population exposure assessment in Serbia for the period 2001-201

The long-term exposure to PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) is the leading global health risk factor. The spatio-temporal variability of annual values of the total PM2.5 concentrations in Serbia is analyzed using the high-resolution (0.01° × 0.01°) gridded data set V4.EU.02 for the period 2001–2016. Population counts and density data were used to calculate the population exposure while the urban land cover data were used to estimate the relations between the size of urban area and the concentration of PM2.5. The mean annual values vary in the range 13.93 μg/m3 –28.91 μg/m3 . The regional differences exist, but the highest values were obtained for urban environments (> 22.5 μg/m3 ). Negative trend of annual PM2.5 is present in most of the parts of the Serbian territory, especially in the eastern parts reaching –0.37 μg/m3 per year (p ≤ .05). More than 99% of the territory of Serbia has the mean annual values under the national safe limit established by regulation (25 μm/m3 ), but comparing to the World Health Organization (WHO) guideline (10 μm/m3 ), all the territory is above the safe level. In line with the trend of urbanization, there is a clear upward trend in the number of population exposed to the higher concentrations of PM2.5. The share of the population exposed to values higher than 25 μg/m3 increased from 6.65% in 2005 to 11.40% in 2015, while comparing to WHO standard, the total population in Serbia is exposed to the values higher than the safe one

Bioactive Lipids Metabolites in amanita virosa

Thrombin is the key serine proteinase of the coagulation cascade and, therefore, a suitable target for inhibition of blood coagulation. An extract of Amanita virosa considerably inhibited thrombin (48%), but showed no inhibitory activity on trypsin. On the basis of inhibition selectivity between thrombin and trypsin and potency of thrombin inhibition, A. virosa constitutes a good starting material for the isolation of further compounds that are active against thrombin. Bioassay oriented fractionation of the extract of A. virosa led to the isolation of a complex mixture of triglycerides (TGs), monoacylglycerols (MAGs), free fatty acids (FAs) and ergosterol. The structures of the isolated lipids metabolites were determined on the basis of chemical and spectroscopic evidences

Bioactive Lipid Metabolites in Amanita Virosa.

Amanita fungi are the main lethal toadstool among the 1000 poisonous mushrooms known in the world. Thrombin is the key serine proteinase of the coagulation cascade and therefore a suitable target for inhibition of blood coagulation. An extract of Amanita virosa considerably inhibited thrombin (48%) and showed no inhibitory activity on trypsin. On the basis of inhibition selectivity between thrombin and trypsin and potency of thrombin inhibition, Amanita virosa constituted a good starting material for isolation of further compounds that are active against thrombin. In a preliminary study, 95 selected mushroom species have been screened in order to find novel specific non-peptidic thrombin inhibitors. The extract of Amanita virosa considerably inhibited thrombin (48% at concentration of 120 \u3bcg/mL). A bioassay oriented fractionation of the extract of Amanita virosa has led to the isolation of active compounds. On the basis of spectroscopic data, chemical reactions and GCMS analysis, complex mixtures of triglycerides, monoacylglycerols, free fatty acids and ergosterol have been isolated and identified