Primena metode atomske apsorpcione spektrofotometrije (AAS) za određivanje sadržaja teških metala u fosfogipsu

Phosphogypsum is formed as a by-product in the process of 'green' phosphoric acid production. This is done in the so called 'wet process' by the action of sulphuric acid on raw phosphate at low temperature ( lt 100 °C). Despite the same molecular formula and marked similarity with natural gypsum, phosphogypsum contains more than 50 impurities, and this is directly connected with the type of phosphate used in the production cycle. The aim of this paper was to consider the possibility of using phosphogypsum for amelioration of solonetz soil, bearing in mind its content of heavy metals, which are rather toxic for human organism and which can be transferred from soil to various plants used in human nutrition. On the other hand, there are very few data in the literature about the determination of heavy metals in phosphogypsum. The content of heavy metals in phosphogypsum was determined by atomic absorption spectrophotometry because this method has broad application in ana­lytical practice due to its high sensitivity, selectivity and precision. The results of the investigation indicate the following average content of heavy metals (in ppm): Fe-785, Pb-45, Zn-45, Cd-7, Mn-8, Co-10, Ni-20 and Cu-17. For the investigation of the effect of phosphogypsum on solonetz soil the following points were taken into consideration: maximum recommended dose of phosphogypsum (7 t/ha) for the amelioration of solonetz soil and the weight of soil layer (from 0 to 20 cm) having an area of 1 ha. The results obtained indicate that the amounts of heavy metals that are introduced into the soil with 7 t/ha of phosphogypsum are in the range from 0.035 to 0.8% of their maximum permissible content for arable soils. This means that only long-term application of phosphogypsum would introduce significant amounts of these elements into the soil.Procesom dobijanja 'zelene' fosforne kiseline tzv. 'mokrim postupkom', dejstvom sumporne kiseline na sirovi fosfat na niskoj temperaturi ( lt 100 °C) kao nus-proizvod nastaje - fosfogips (sa faktorom 5:1, u odnosu na H3PO4). Uprkos istoj molekulskoj formuli i izraženoj sličnosti sa prirodnim gipsom, fosfogips sadrži preko 50 vrsta nečistoća, što je u direktnoj vezi sa vrstom fosfata koji je korišćen u proizvodnom ciklusu. Cilj rada bio je razmatranje mogućnosti primene fosfogipsa za melioraciju soloneca, sa aspekta sadržaja teških metala, koji su izuzetno toksični i kumulativni za čovekov organizam, a iz zemljišta prelaze u biljke, kojima se čovek hrani. Sa druge strane, u literaturi se nalaze veoma oskudni podaci o ispitivanju sadržaja teških metala u fosfogipsu. Sadržaj teških metala u fosfogipsu određivan je metodom atomske apsorpcione spektrofotometrije (AAS), budući da je to metoda koja je našla veliku primenu u praksi usled visoke osetljivosti, selektivnosti i preciznosti. Rezultati ispitivanja su pokazali sledeći sadržaj teških metala (u ppm): Fe-785, Pb-45, Zn-45, Cd-7, Mn-8, Co-10, Ni-20, Cu-17. Za ispitivanje uticaja primene fosfogipsa za melioraciju soloneca, uzeta je u obzir preporučena maksimalna norma za gipsovanje soloneca od 7 t/ha zemljišta i težina sloja debljine od 0 do 20 cm a površine 1 ha. Dobijeni rezultati su pokazali da se preporučenom maksimalnom normom za gipsovanje soloneca fosfogipsom unosi po 1 ha zemljišta od 0,035 do 0,8% od maksimalno dozvoljenog sadržaja teških metala - MDK vrednosti, što znači da bi tek višegodišnjom upotrebom fosfogipsa došlo do unošenja značajnijih količina ovih elemenata u zemljište. Kako se proces melioracije soloneca najčešće vrši u intervalu od 5 do 6 godina, unošenje teških metala bilo bi u zanemarljivoj količini i bez uticaja na životnu sredinu

Self-diffusion of Cd++ Ions in Hydrated CdX Zeolite

The fractional attainment of the isotopic equilibrium between a Cd(N03)2 solution and a 115Cd-labelled CdX zeolite has been measured as a function of time, particle size of zeolite and temperature. The experimental kinetic data have been interpreted in terms of the Brown-Sherry-Krambeck model and the self-diffusivities and diffusional activation parameters of Cd++ ions in zeolite CdX have been calculated

DFT study of the radical scavenging activity of isoxanthohumol, humulones (α-acids), and iso-α-acids from beer

Humulones and iso-humulones are potent natural antioxidants found in beer. In this study, density functional theory (DFT) method was applied for elucidating the structure-antioxidant activity relationship and molecular mechanism of antioxidant activity of eight bioactive humulones previously identified in different beer samples: isoxanthohumol, (R)- and (S)-adhumulone, cis- and trans-iso-adhumulone, cis- and trans-iso-n-humulone, and desdimethyl-octahydro-iso-cohumulone. The calculated bond dissociation enthalpies (BDEs) suggest that desdimethyl-octahydro-iso-cohumulone was the most potent compound with BDEs 5.1 and 23.9 kJ/mol lower compared to the values for resveratrol in gas phase and water, respectively. The enolic –OH is the most reactive site for hydrogen atom transfer (HAT). The presence of β-keto group with respect to enolic –OH diminishes the HAT potency via the formation of a strong intramolecular hydrogen bond. Another common antioxidant mechanism, single electron transfer followed by proton transfer (SET-PT), is only feasible for isoxanthohumol. The results of this study indicate a strong correlation between the increased antioxidant activity of beer products and the higher content of reduced iso-α-acids

Natural and artificial (90Sr) radionuclides in some carbonated mineral waters used in Serbia

A radiological characterization of 7 different carbonated mineral water samples collected in the local supermarkets in the area of Belgrade (produced in Serbia) was carried out. Analysis included determination of gross alpha and gross beta activities. The obtained results showed that the natural activity concentrations of alpha and beta emitting radionuclides in carbonated mineral water samples were within World Health Organization recommended levels, except for the Heba Strong and Kiseljak samples where the beta activity exceeds 1 Bq/L. For these two water samples gamma spectrometry analysis was performed as well as determination of 90Sr by oxalic method. The instrumentation used to count the gross alpha and gross beta activities, as well as for 90Sr, was a/b low level proportional counter Thermo Eberline FHT 770 T. Gamma spectrometric measurements were performed using a HPGe Canberra detector with a counting efficiency of 20%. The annual effective dose equivalent due to ingestion of investigated waters was calculated for age group >17, and obtained values are lower than 0.1 mSv recommended reference level. Finally, a comparison of the investigated waters with worldwide data was made. [Projekat Ministarstva nauke Republike Srbije, br. III43009

Uticaj cimiazol hidrohlorida na mitotsku i proliferativnu aktivnost u kulturama humanih limfocita

Cymiazole hydrochloride is the active ingredient of a synthetic systemically acting acaricide used in beekeeping (Apitol®, Apichem®). Considering that residues of cymiazole hydrochloride were detected in all bee products being used for human nutrition and as alternative medications in human and veterinary medicine, the objective of this study was to evaluate the effects of cymiazole hydrochloride on mitotic activity of cultured human lymphocytes. The mitotic and proliferation indices in phytohaemagglutinin-activated human peripheral blood lymphocytes were determined using three experimental concentrations of cymiazole hydrochloride (0.01; 0.1; 1mg/ml). All experimental concentrations of cymiazole hydrochloride increased mitotic index values (MI) by a statistically highly significant amount (p lt 0.001). Moreover, proliferation index (PI) was also changed very significantly (p lt 0.001) after each experimental cymiazole hydrochloride treatment. The dose dependent increase in proliferation index values clearly demonstrates the ability of cymiazole hydrochloride to induce significant alterations of cell cycle kinetics having an influence on G0 state and arousing cell division. This indicates a risk from consuming bee products with cymiazole hydrochloride residues particularly in those predisposed to malignant diseases. Strict respect to the withrawal time while using cymiazole hydrochloride (Apitol®, Apichem®) is of great importance because residue levels higher than the permitted one can easily occur in honey and other bee products from treated honey bee colonies.Cimiazol hidrohlorid predstavlja aktivnu supstancu sintetičkih akaricida sa sistemskim dejstvom koji se koriste u pčelarstvu (Apitol®, Apichem®). Obzirom da su rezidue cimiazol hidrohlorida detektovane u svim pčelinjim proizvodima, koji se koriste u ishrani i kao alternativni lekovi u humanoj i veterinarskoj medicini, cilj ovog rada bio je ispitivanje efekata cimiazol hidrohlorida na mitotsku i proliferativnu aktivnost humanih limfocita u kulturi. Analizirani su mitotski i proliferativni indeksi humanih limfocita aktiviranih fitohemaglutininom pri čemu su koršćene tri eksperimentalne koncentracije cimiazol hidrohlorida u opsegu od 0.001 mg/ml do 1 mg/ml. Sve tri eksperimentalne koncentracije cimiazol hidrohlorida izazvale su vrlo visoko signifikantno (p lt 0.001) povećanje vrednosti mitotskog indeksa (MI) humanih limfocita. Takođe, vrednosti proliferativnog indeksa (PI) su vrlo visoko signifikantno (p lt 0.001) povećane nakon svakog eksperimentalnog tretmana cimiazol hidrohloridom. Dozno zavisno povećanje vrednosti proliferativnog indeksa jasno pokazuje sposobnost cimiazol hidrohlorida da izazove značajne promene u kinetici ćelijskog ciklusa utičući na G0 tačku i podstičući ćelijsku deobu, što ukazuje na rizik prilikom konzumiranja pčelinjih proizvoda sa reziduama cimiazol hidrohlorida, posebno kod jedinki sklonih malignitetima. Izuzetno je značajno strogo poštovanje karence prilikom upotrebe cimiazol hidrohlorida (Apitol®, Apichem®) jer rezidue, u količini većoj od dozvoljene, mogu veoma lako dospeti u med i druge pčelinje proizvode dobijene od tretiranih pčelinjih društava

Calibration of HPGe Detectors for Environmental Samples Using GEANT4 Simulation

Determination of full energy peak efficiency is one of the most important tasks that have to be performed before gamma spectrometry. Calibration of the measurement system for measuring environmental samples poses a special challenge to the laboratory. Many different approaches to this task have been developed and examined. One of the most detailed is GEANT4, a Monte Carlo simulation toolkit developed for wide variety of applications. The aim of this paper is to apply GEANT4 simulation for calibration of three HPGe detectors, for measurement of aerosol, plant and coal-like environmental samples. The detectors were modeled using the certificate provided by the manufacturer. The samples chosen for the simulation were secondary reference materials produced in the Laboratory for the purpose of experimental calibration. The efficiencies obtained using a simulation were compared with experimental results, in order to evaluate the trueness of the results. Measurement uncertainties for both simulation and experimental values were estimated in order to see whether the results of the realistic measurement fall within acceptable limits.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Calibration of HPGe Detectors for Environmental Samples Using GEANT4 Simulation

Determination of full energy peak efficiency is one of the most important tasks that have to be performed before gamma spectrometry. Calibration of the measurement system for measuring environmental samples poses a special challenge to the laboratory. Many different approaches to this task have been developed and examined. One of the most detailed is GEANT4, a Monte Carlo simulation toolkit developed for wide variety of applications. The aim of this paper is to apply GEANT4 simulation for calibration of three HPGe detectors, for measurement of aerosol, plant and coal-like environmental samples. The detectors were modeled using the certificate provided by the manufacturer. The samples chosen for the simulation were secondary reference materials produced in the Laboratory for the purpose of experimental calibration. The efficiencies obtained using a simulation were compared with experimental results, in order to evaluate the trueness of the results. Measurement uncertainties for both simulation and experimental values were estimated in order to see whether the results of the realistic measurement fall within acceptable limits.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Supplementary data for the article: Vitorović-Todorović, M. D.; Koukoulitsa, C.; Juranić, I. O.; Mandić, L. M.; Drakulić, B. J. Structural Modifications of 4-Aryl-4-Oxo-2-Aminylbutanamides and Their Acetyl- and Butyrylcholinesterase Inhibitory Activity. Investigation of AChE-Ligand Interactions by Docking Calculations and Molecular Dynamics Simulations. European Journal of Medicinal Chemistry 2014, 81, 158–175. https://doi.org/10.1016/j.ejmech.2014.05.008

Supplementary material for: [https://doi.org/10.1016/j.ejmech.2014.05.008]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1808]Related to accepted version:[http://cherry.chem.bg.ac.rs/handle/123456789/2907

Temperature and magnetic field effects on the activity of protocerebral neurosecretory neurons and corpora allata in Cerambyx cerdo L. larvae

The effects of constant temperature and an extremely low-frequency magnetic field (ELFMF, 50 Hz and average induction of 20 mT) on the activity of medial protocerebral neurosecretory neurons (A1 and A2) and corpora allata were investigated in Cerambyx cerdo L. larvae after 30 days of exposure. Both constant temperature of 23°C and the ELFMF led to decrease in activity of A1 and A2 neurosecretory neurons and increase in activity of corpora allata compared to the control group (larvae from natural conditions). The changes are more pronounced in A2 than A1 neurons.Ispitivan je uticaj konstantne temperature i ekstremno niskofrekventnog magnetnog polja (ELFMF, 50 Hz i prosečna indukcija 20mT) na aktivnost medijanih protocerebralnih neurosekretnih neurona (A1 i A2) i corpora allata kod larvi Cerambyx cerdo posle 30 dana izlaganja i konstantna temperatura od 23°C i ELFMF dovode do smanjenja aktivnosti A1 i A2 neurosekretnih neurona i povećanja aktivnosti corpora allata u poređenju sa kontrolnom grupom (larve iz prirodnih uslova). Promene su više izražene kod A2 nego kod A1neurona.nul