P estimation of radiological impact on residents due to household storage of coal used for heating in Serbia

This pa per aims to es ti mate a po ten tial ra dio log i cal risk from dif fer ent kinds of coals used for do mes tic heat ing in Ser bia, by mea sur ing the ac tiv ity con cen tra tion of radionuclides and ra don ex ha la tion rate. The ob tained ra don mass ex ha la tion rate ranges from (5.3 +/- 3.1) mu Bqkg-1s-1 to (70.3 +/- 9.4) mu Bqkg -1s-1 and was high est for lig nite type of coal. It is es ti mated that coal stored in the base ment could con trib ute up to 50 Bqm-3 of in door ra don con cen tra tion at the ground level. Ac tiv ity con cen tra tions of 226Ra, 232Th, 40K, 238U, 235U, and 210Pb in ana lysed coal sam ples agree with pre vi ously re ported con cen tra tions of coal used in Ser bia. The values of radium equivalent concentration and external hazard index indicate that the used coal does not represent a significant radiation hazard

Biofilm forming microorganisms on various substrata from greenhouse of Botanical Garden “Jevremovac”

Diversity of subaerial biofilm forming cyanobacteria, algae and fungi was investigated on 10 different substrata from greenhouse of Botanical Garden “Jevremovac”. Out of 37 documented taxa, 16 cyanobacterial and 10 algal taxa were identified. Remaining 11 taxa belong to the Kingdom of Fungi. The highest diversity of biofilm forming microorganisms, a total of 24 taxa, was detected on the corroded metal surface, while significantly lower number of taxa was recorded on other examined substrata. Cyanobacterium Porphyrosiphon sp., diatom Achnanthes sp. and green algae Chlorella sp. and Chlorococcum minutum were the most frequently encountered photosynthetic components of biofilms. In all analyzed samples, Trichoderma sp., followed by Cladosporium sp. and Rhizopus stolonifer, were the most frequently identified fungi. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI176020, Grant no. OI176018, and Grant no. OI173032

Evaluating recharge estimates based on groundwater head from different lumped models in Europe

Study region: The study uses 78 groundwater head time series across 10 European countries with various geological and hydrological settings. Study focus: The estimation of groundwater recharge using time series analysis and lumped modelling based on groundwater head time series is a low-cost and practical method. However, lumped recharge estimation models based on groundwater level variations are uncertain, and successful applications are known to depend on both climate and hydrogeological setting. Here, we assess the suitability of three different models to estimate recharge (Metran - Transfer Function-Noise model, AquiMod - groundwater level driven hydrological model, and GARDÉNIA - lumped catchment model). New hydrological insights: Results showed that while all three models generally did well during the modelling of groundwater heads, the resulting recharge estimations from the models were different. The analysis showed that the transfer-noise modelling of groundwater heads with recharge and evapotranspiration in Metran is not generally applicable for recharge estimation. The addition of physical information in AquiMod improved the recharge estimations, but the reliability was still limited without control of the water balance due to non-uniqueness. By adding discharge information to the modelling, GARDÉNIA can provide more reliable recharge values. Thus, recharge estimation from groundwater head time series without water balance information must be considered uncertain with low precision, but applicability can be improved when including knowledge of the local system

Semaphorin-4A, an activator for T-cell-mediated immunity, suppresses angiogenesis via Plexin-D1

Originally identified as axon guidance molecules, semaphorins are now known to be widely expressed mediators that play significant roles in immune responses and organ morphogenesis. However, not much is known about the signaling pathways via which they exert their organ-specific effects. Here we demonstrate that Sema4A, previously identified as an activator of T-cell-mediated immunity, is expressed in endothelial cells, where it suppresses vascular endothelial growth factor (VEGF)-mediated endothelial cell migration and proliferation in vitro and angiogenesis in vivo. Mice lacking Sema4A exhibit enhanced angiogenesis in response to VEGF or inflammatory stimuli. In addition, binding and functional experiments revealed Plexin-D1 to be a receptor for Sema4A on endothelial cells, indicating that Sema4A exerts organ-specific activities via different receptor-mediated signaling pathways: via Plexin-D1 in the endothelial cells and via T-cell immunoglobulin and mucin domain-2 in T cells. The effects of Sema4A on endothelial cells are dependent on its ability to suppress VEGF-mediated Rac activation and integrin-dependent cell adhesion. It thus appears that Sema4A–Plexin-D1 signaling negatively regulates angiogenesis