Absorbed Dose Uncertainty Estimation for Proton Therapy

Successful radiotherapy treatment depends on the absorbed dose evaluation and the possibility to define metrological characteristics of the therapy beam. Radiotherapy requires tumor dose delivery with expanded uncertainty less than +/- 5 %. It is particularly important to reduce uncertainty during therapy beam calibration as well as to apply all necessary ionization chamber correction factors. Absorbed dose to water was determined using ionometric method. Calibration was performed in reference cobalt beam. Combined standard uncertainty of the calculated absorbed dose to water in 65 MeV proton beam was +/- 1.97% while the obtained expanded uncertainty of absorbed dose for the same beam quality was +/- 5.02%. The uncertainty estimation method has been developed within the project TESLA

Koncentracije elemenata kod dve vrste riba sa različitim preferencijama staništa i ishrane (šaran i manić) u Dunavu kod Beograda

Akvatični ekosistemi se uobičajeno smatraju krajnjim recipijentima zagađenja toksičnim metalima, čiji izvori mogu biti prirodni ili, najčešće, antropogeni. Ova klasa zagađivača predstavlja značajnu pretnju za životnu sredinu i vrste koje žive u njoj, kao i potencijalnu pretnju za ljudsko zdravlje. Osim toksičnih elemenata, i elementi u tragovima, kao i esencijalni mikronutrijenti, mogu pokazivati toksična svojstva ako su prisutni u većim koncentracijama. Dunav je recipijent zagađenja oslobođenog oko industrijskih gradova koji se nalaze duž toka ove reke. Koncentracije metala u tkvima riba zavise od većeg broja faktora, među kojima veliki značaj imaju ishrana i stanište. Koncentracije 15 elemenata (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Se, Sr i Zn) analizirane su upotrebom ICP-OES u uzorcima jetre i škrga jedinki šarana i manića uhvaćenih u Dunavu u blizini Beograda. Elementi Li, Ni i Pb nisu detektovani u uzorcima. Mann-Whitney U test je ukazao na postojanje značajne razlike između šarana i manića u odnosu na koncentracije nekoliko elemenata, i u jetri i u škrgama. PCA analiza je pokazala da šaran i manić formiraju dve odvojene grupe na osnovu koncentracije elemenata u analiziranim tkivima. Jetra šarana karakteriše se visokim koncentracijama Cd, Cu i Zn, a škrge visokom koncentracijom Zn, dok se kod manića i jetra i škrge karakterišu visokim koncentracijama As. U škrgama šarana detektovana je viša koncentracija Zn. Šaran živi na svim dubinama i preferira staništa sa gustom akvatičnom vegetacijom i potopljenim drvećem, a u pogledu ishrane predstavlja omnivornu vrstu koja konzumira i detritus. Odrasli manić je riba bentosa koj preferira kamenitu podlogu i oportunistički je predator. Različita ishrana šarana i manića može biti uzrok razlika u koncentracijama elemenata u jetri, dok razlike u preferencijama staništa mogu ukazati na razlike u škrgama

Koncentracije elemenata u mišićnom tkivu dve vrste riba različitog trofičkog nivoa (uklija i štuka) u Dunavu kod Beograda

Industrijski i komunalni efluenti uzrok su visokih koncentracija nekih elemenata u rečnoj vodi. Procenjuje se da se u Srbiji oko 90% industrijskih otpadnih voda ispušta u vodotokove bez prethodne obrade. Koncentracije elemenata u tkivima riba pod uticajem su kako prisustva zagađenja staništa, tako i trofičkog položaja i veličine ribe. Koncentracije 15 elemenata analizirane su upotrebom ICP-OES u uzorcima mišićnog tkiva uklije i štuke uhvaćenih na ušću Save u Dunav, između oktobra 2011. i marta 2012. godine. Elementi Cd, Co, Li i Pb nisu detektovani u uzorcima. Jednofaktorska ANOVA je pokazala da postoje značajne razlike između mišićnog tkiva uklije i štuke u odnosu na koncentracije Ba, Cu, Fe i Zn. U mišićnom tkivu štuke, koja predstavlja piscivornu vrstu, detektovana je viša koncentracija Hg nego kod uklije, što ukazuje na biomagnifikaciju kroz lance ishrane, dok je kod uklije, kao obligatnog zooplanktivora, detektovana viša koncentracija Zn, što potvrđuje tendenciju negativne korelacije Zn sa trofičkim nivoom ribe. U mišiću uklije, od analiziranih elementa samo je kod Se uočena pozitivna korelacija sa totalnom dužinom tela (TL), dok je kod štuke uočena negativna korelacija Se sa težinom (W) i pozitivna korelacija koncentracije Al sa TL i W. Kod obe vrste ukupno je nađeno 20 korelacija (14 pozitivnih i 6 negativnih) između koncentracija elemenata u mišićnom tkivu. Kod uklije, najveći broj korelacija sa drugim elementima uočen je kod Mn i Sr. Kod štuke, pozitivna korelacija uočena je između Fe, Se i Zn, dok su sva tri elementa bila negativno korelisana sa Al, a Se i Zn pozitivno sa Mn i Sr

MONITORING OF IMMUNE RESPONSE IN VIROLOGIC SUCCESSFULLY TREATED HIV-INFECTED PATIENTS IN SOUTHEASTERN SERBIA

The number of CD4 lymphocytes defines the evolutional stage of HIV-infection and is the most important for a reliable estimation of the individual risk of developing AIDS. However, it is difficult to predict the degree of immune reconstitution during antiretroviral therapy, as it varies significantly from one person to another. Further investigations to better understand the limitations of immunological success are necessary to improve the response to treatment and regimen durability. The current study includes HIV-infected patients in Southeastern Serbia with achieved virologic suppression of HIV infection. The CD4 count was determined by flow cytometry, and was correlated with the duration of treatment, initial number of CD4 cells, type of antiretroviral therapy, mode of transmission of infection, age and gender of examinees. The resulting arithmetic mean and standard deviation of CD4 number was 473±259 cells/µl (range, 1130 cells/µl). There was no statistically significant correlation between the values of CD4 count and length of treatment, stage of the infection at which the therapy was started, treatment profile, method of infection, age or gender. The obtained results are comparable with the existing studies that follow immunological response to antiretroviral therapy and primarily point out the issue of substantial individual response variability, which has not yet been fully elucidated

Lifestyle, Physical Activity, Eating and Hygiene Habits: A Comparative Analysis Before and During the COVID-19 Pandemic in Student Population

Background: Changing daily habits such as diet, hygiene and physical activity may be some of the consequences of the COVID-19 pandemic. The aim of the study was to analyze the effect of this pandemic on lifestyle, physical activity, eating and hygiene habits among students. Methods: This cross-sectional study involved 171 students from the Faculty of Medical Sciences, University of Kragujevac, Serbia. Data were statistically analyzed using Wilcoxon Signed-Rank test, Marginal homogeneity test and Chi-square test. The differences were considered statistically significant when p ≤ 0.05. Results: In this study, it was observed that the most common physical activity before the pandemic was walking, while during the pandemic was home exercising. Compared to the period before the pandemic, there was no difference in the time spent engaging in daily physical activity (p = 0.334). However, there was a significant increase in sitting time during the pandemic (p = 0.005). Difference was noticed in the use of breakfast, the number of meals, and the type of fat in the diet before and during the pandemic (p = 0.000). During the pandemic, there was an increase in the use of fruits (p = 0.000), vegetables, and nuts (p = 0.001), while the use of fast food and alcohol have decreased. During the COVID-19 pandemic, a significant increase in the use of dietary supplements was observed (40.2%), (p = 0.008). Conclusions: Given that the COVID-19 pandemic is ongoing, certain changes in lifestyle observed in this study should be confirmed in more extensive population studies

The importance of copper in pathology of mesial temporal lobe epilepsy

More and more studies are identifying the regulation of metal homeostasis as one of the key points of central nervous system’s well-being. Epilepsy is a particularly interesting neurological condition when viewed in terms of the correlation between the amount of metals and the development of a seizure. This lecture will present contribution of our group to the field of metal biology in epilepsy by mapping brain metals in sclerotic hippocampus resected from drug resistant mesial temporal lobe epilepsy (mTLE) patients as surgical therapeutic approach. Direct insight into this epileptogenic area, by two powerful techniques, optical emission and mass spectrometry, has led us to investigation of copper turnover. Namely, among the examined metals, we found the deficiency of copper in sclerotic hippocampus on two levels: (i) in whole structure (ii) and locally in the areas of neuronal loss, with significant correlation between copper concentration and neuron density. Furthermore, analysis of copper metalloproteins showed: (i) significant increase or decrease in levels of protein that is participating in copper transport into the cell (CTR1) depending on the degree of hippocampal neuronal loss; (ii) and lower activity of an enzyme in which copper is part of the active site, cytochrome c oxidase, in sclerotic hippocampi of patients compared to control tissue. In our further investigations it remained to be determined whether changes in copper concentrations and copper metalloproteins are causal to pathology of mTLE or they represent epiphenomenon