Prirodni radionuklidi u mahovinama iz istočne Srbije u razdoblju 2008.-2013.

The results of the study on natural radionuclide content in 102 samples of the moss species randomly collected in 2008-2013 at 30 locations of eastern Serbia are presented in the paper. The activity concentration values of 238U, 226Ra, 232Th, 40K, and 7Be determined by gamma spectrometry were within the intervals: 238U (1.1–50) Bq kg-1, 226Ra (1.1–41) Bq kg-1, 232Th (1.4–28) Bq kg-1, 40K (64–484) Bq kg-1 and 7Be (88–227) Bq kg-1, not standing out of the average data reported for this region. The distribution of the obtained data for 226Ra, 232Th, and 238U activity concentration in the analysed mosses has shown values up to 10 Bq kg-1 with frequencies 47.1 %, 54.9 % and 48.0 %, respectively. The obtained activity concentration values of primordial 40K and cosmogenic radionuclide 7Be were up to 500 Bq kg-1 and about 90 % of all the results for 7Be uptake by mosses were in the 200-250 Bq kg-1 concentration range.U radu su prikazani rezultati ispitivanja sadržaja prirodnih radionuklida u 102 uzorka mahovine prikupljene metodom slučajnoga uzorka u razdoblju 2008.-2013. na 30 lokacija u istočnoj Srbiji. Vrijednosti koncentracija (specifične aktivnosti) radionuklida 238U, 226Ra, 232Th, 40K i 7Be, određene primjenom spektrometrije gama zračenja, nalaze se u opsegu: 238U (1,1 – 50) Bq kg-1, 226Ra (1,1 – 41) Bq kg-1, 232Th (1,4 – 28) Bq kg-1, 40K (64 – 484) Bq kg-1 i 7Be (88 – 227) Bq kg-1 te ne odstupaju značajno u odnosu na ostale rezultate dobivene za ovu regiju. Distribucija dobivenih podataka o koncentracijama 238U, 226Ra i 232Th u analiziranoj mahovini pokazuje vrijednosti do 10 Bq kg-1, s učestalošću 54,9 %, 48,0 % i 47,1 %. Dobivene vrijednosti koncentracija primordijalnoga 40K i kozmogenoga 7Be bile su do 500 Bq kg-1, pri čemu je oko 90 % svih rezultata za 7Be akumuliranog u mahovinama bilo u opsegu koncentracija 200 – 250 Bq kg-1

Sexual selection can reduce mutational load in Drosophila subobscura

According to theoretical predictions sexual selection can reduce mutational load through male mating success. Males of good genetic quality should be more successful in matings, compared to the males of low genetic quality, thus in this way females can prevent deleterious alleles to be transmitted to the next generation. We tested this hypothesis through set up of two experimental groups from same genetic pool, where in one group genetic quality was manipulated by ionizing radiation. Within each group opportunity for choosing mates was imposed: males and females had no choice or had multiple choice. Mutational load was measured through the variability of different fitness components: fecundity and egg-to-adult viability. Our results indicate that sexual selection can reduce mutational load, only for fecundity. Group with the presence of female choice exhibited higher fecundity than group in which sexual selection was experimentally eliminated, but only in 'irradiated' group. There was no overall difference in egg-to-adult viability between different sexual selection regimes in any of the group. It should be considered that sexual selection can cause sexual conflict, and potential opposite effects of sexual selection and sexual conflict on fitness. Genetic structure of populations, in terms of the level of mutational load, is an important factor which can determinate the role of sexual selection.Prema teorijskim očekivanjima seksualna selekcija može smanjivati mutaciona opterećenja u populacijama, preko uspešnosti mužjaka u parenju. Mužjaci koji su boljeg genetičkog kvaliteta bi trebalo da budu uspešniji u parenju od mužjaka lošijeg genetičkog kvaliteta. Na taj način bi ženke mogle da smanje prenošenje štetnih alela u sledeću generaciju. Ova hipoteza je testirana uspostavljanjem dve eksperimentalne grupe od istog genetičkog pula jedinki, pri čemu su u jednoj mutacije indukovane jonizujućim zračenjem. Unutar svake grupe je nametnuta mogućnost izbora u parenju: mužjaci i ženke nisu imali izbor, ili su imali višestruki izbor. Mutaciona opterećenja su merena preko dve komponente adaptivne vrednosti: fekunditeta i preživljavanja od stadijuma jaja do adulta. Dobijeni rezultati ukazuju da seksualna selekcija može imati uticaj na smanjivanje mutacionih opterećenja ali samo za fekunditet. U prisustvu seksualne selekcije su vrednosti fekunditeta bile veće u odnosu na vrednosti koje su dobijene kad je seksualna selekcija eksperimentalno uklonjena, ali samo u okviru 'ozračene' grupe. Razlike u preživljavanju od jaja do adulta između različitih režima seksualne selekcije nisu dobijene ni u jednoj od grupa. Kako seksualna selekcija često uzrokuje i seksualni konflikt, treba uzeti u obzir njihovo potencijalno delovanje u suprotnim pravcima na adaptivnu vrednost. Genetička struktura populacija, koja podrazumeva i veličinu mutacionih opterećenja, može biti važan faktor od koga će i zavisiti delovanje seksualne selekcija na adaptivnu vrednost.Projekat ministarstva br. 17301

Rare earth dual-doped multifunctional hydroxyapatite particles for potential application in preventive medicine

Composite biomaterials based on nano hydroxyapatite (HAp) are the subject of numerous studies in reconstructive medicine. Multifunctional and nanoparticulate systems based on HAp and biodegradable polymers are successfully designed as systems for controlled and systemic drug delivery suitable for use in reconstructive medicine [1, 2]. Thanks to the stability and flexibility of the apatite structure, Ca ions can be replaced with various elements (Zn, Sr, Mg, Co, etc.) [3, 4]. Doping the apatite structure enables potential application of this material in preventive medicine, too. Multimodal imaging (MI) is a new and promising technique for improved diagnosis and it is patient-friendly because it saves time. MI has recently attracted much attention due to the advantageous combination of various imaging modalities, such as computer tomography, photoluminescence and magnetic resonance imaging.Poster presented at the Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018Abstract: [https://hdl.handle.net/21.15107/rcub_dais_3663

Rare earth dual-doped multifunctional hydroxyapatite particles for potential application in preventive medicine

Composite biomaterials based on nano hydroxyapatite (HAp) are the subject of numerous studies in reconstructive medicine. Multifunctional and nanoparticulate systems based on HAp and biodegradable polymers are successfully designed as systems for controlled and systemic drug delivery suitable for use in reconstructive medicine. Thanks to the stability and flexibility of the apatite structure, Ca ions can be replaced with various elements (Zn, Sr, Mg, Co, etc.). Doping the apatite structure enables potential application of this material in preventive medicine, too. Multimodal imaging (MI) is a new and promising technique for improved diagnosis and it is patient-friendly because it saves time. MI has recently attracted much attention due to the advantageous combination of various imaging modalities, such as computer tomography (CT), photoluminescence (PL) and magnetic resonance imaging (MRI). For such a promising approach, we devised new multimodal contrast agents using the doping of a HAp matrix with rare earth (RE) ions. Pure HAp (Ca5(PO4)3(OH)), magnetic HAp:Gd (Ca4.85Gd0.15(PO4)3(OH)), down-converting HAp:Gd,Eu (Ca4.94Gd0.02Eu0.04(PO4)3(OH)) and up-converting HAp:Gd,Yb/Tm (Ca4.85 Gd0.03Yb0.1Tm0.02(PO4)3(OH)) were synthesized using a hydrothermal procedure. Morphological and structural characteristics of the particles were obtained using X-ray powder diffraction (XRPD), scanning and transmission electron microscopy (SEM/TEM), energy dispersive X-ray spectrometry (EDX), photoluminescence (PL), Fourier Transform Infrared (FTIR) and diffuse reflectance spectroscopy (DRS). The results show that needle-like nano- or microparticles were obtained in all systems. Their phase composition and uniform distribution of dopants were confirmed by the structural refinement of the XRPD data, change in the band gap, and luminescence spectra recorded using different excitation sources (λ= 370, 394 and 977 nm).Poster: [https://hdl.handle.net/21.15107/rcub_dais_4064

Study of oil type pollutant adsorption on Vrbas River sediments (Bosnia and Herecgovina)

PAHs are a group of ubiquitous persistent organic pollutants that cause sever global environmental concerns for ecosystems and human health due to their potential toxicity and carcinogenicity. PAHs are a group of organic pollutants strongly related to anthropogenic activities such as settlement, transport, and industrial development. Due to their lipophilicity and persistence, PAHs are readily adsorbed in the particulate matter once they enter the urban river system and are finally deposited in the sediment. [1] The aim of this work was to evaluate the distribution of PAHs in the sediments of Vrbas River, to assess their occurrence and to establish the origin (pyrogenic/petrogenic) of pollution sources.This study focussed on investigation on the state of pollution and identification of potential sources of contamination of river sediments by polycyclic aromatic hydrocarbons along entire course of the Vrbas River (Bosnia and Herzegovina). Nineteen sampling points were selected covering the entire course of the Vrbas River (Bosnia and Herzegovina). The samples were extracted in a Soxhlet apparatus and fractionated using column chromatography. In the fraction of aromatic hydrocarbons, PAHs were analysed by gas chromatography - mass spectrometry (GC-MS) in a selected ion monitoring (SIM) mode. The ions monitored were: m/z = 128 (naphthalene), m/z = 152 (acenaphthylene), m/z = 154 acenaphthene), m/z = 166 (fluorene), m/z = 178 (phenanthrene andanthracene), m/z = 202 (fluoranthene and pyrene), m/z = 228 (benzo[a]anthracene and chrysene), m/z = 252 (benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo[e]pyrene and benzo[a]pyrene), m/z = 276 (indeno[1,2,3-c,d]pyrene and benzo[g,h,i]perylene), and m/z = 278 (dibenzo[a,h]anthracene) [2]. Thereafter numerous PAH diagnostic ratios were calculated and analysed. High molecular weight polycyclic aromatic hydrocarbons (4, 5 or 6 rings) are more prevalent in the observed samples. The analysis of different PAH diagnostic ratios indicate the pyrogenic PAHs origin. In most samples, according to calculated parameters, these are combustion products of coal, grass, and wood, while in some samples these parameters implicate the fuel combustion origin of PAHs. No regularity was observed in the distribution of PAHs in the samples, indicating the existence of multiple sources of these compounds in the investigated area. Thus, the conclusion is that this area was exposed to both point and diffuse sources of PAH contaminants.[https://www.mrs-serbia.org.rs/index.php/yucomat-books-of-abstracts/yucomat-wrtcs-202

Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration

During the last decade zinc oxide (ZnO) has attracted considerable attention as a promising material for electronic, optoelectronic and spintronic devices. ZnO has a wide bandgap (3.37 eV at room temperature) and relatively large exciton binding energy (60 meV) which enables multifunctional application. Until now ZnO-based materials have been used as UV and blue light emitters, varistors, thermistors, semiconductors, photoanodes, and other. Various approaches have been applied to improve functional properties of zinc oxide, such as: fabrication of ZnO-based heterojunction particles, particles’ surface sensitization, hydrogenation, etc. It has been found that intrinsic defects (vacancies, interstitials and antisites) in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, correlation of the intrinsic defects concentration with optical and electrical properties of ZnO materials is of great importance for their further application in opto-electronic devices. In this study we investigated the influence of intrinsic defects concentration on the optical, electrical and photoelectrocatalytic properties of ZnO materials. To obtain ZnO powder with a high concentration of intrinsic defects microwave processing of precipitate was employed, while for further varying of defects concentration, the powder was thermally treated in three different atmospheres: air, argon and oxygen. The ZnO powder was uniaxially pressed (P = 100 MPa) in cylindrical compacts (R= 6 mm and h approx. 3 mm) which were sintered in different atmospheres by heating rate of 10 °/min up to 1100 °C, and with dwell time of 1 h. To study a crystal structure of ZnO samples XRD and Raman spectroscopy were used, while for microstructural investigation field emission scanning electron micrographs were recorded. Optical properties were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of intrinsic defects in ZnO crystal lattice on functional properties, XPS, photoluminescence, electroluminescence and electrochemical impedance spectra were analyzed. A detailed analysis of the experimental results imply that a high concentration of intrinsic defects, in particular oxygen vacancies, is of the greatest importance for tunable light-emitting diode application and significant for the photoanode properties. To support our experimental observation we performed ab initio calculations based on density functional theory (DFT)

REVERSE ENGINEERING OF THE MITKOVIC TYPE INTERNAL FIXATOR FOR LATERAL TIBIAL PLATEAU

In orthopaedic surgery it is very important to use proper fixation techniques in the treatment of various medical conditions, i.e. bone fractures or other traumas. If an internal fixation method, such as plating, is required, it is possible to use Dynamic Compression Plates (DCP) or Locking Compression Plates (LCP) and their variants. For DCP implants it is important to match the patient's bone shape with the most possible accuracy, so that the most frequent implant bending is applied in the surgery. For LCP implants it is not so important to match the patient’s bone shape, but additional locking screw holes are required. To improve the geometrical accuracy and anatomical correctness of the shape of DCP and to improve the LCP geometric definition, new geometrical modelling methods for the Mitkovic type internal fixator for Lateral Tibia Plateau are developed and presented in this research. The presented results are quite promising; it can be concluded that these methods can be applied to the creation of geometrical models of internal fixator customized for the given patient or optimized for a group of patients with required geometrical accuracy and morphological correctness

Local adaptation at fine spatial scale through chromosomal inversions and mito-nuclear epistasis: Findings in Drosophila subobscura (Diptera: Drosophilidae)

To explore local adaptation in wild populations at a fine spatial scale we characterized the genetic variability of eight closely located populations of Drosophila subobscura and its associations with microhabitat environmental conditions. Three different genetic markers were assessed: chromosomal inversions, a SNP of mitochondrial ND5 gene and nuclear microsatellites. Population genetic analyses of chromosomal variability revealed significant genetic differentiation between these populations. Gene arrangement frequencies on the E chromosome contributed most to these differences. We also investigated role of mito-nuclear epistasis in mitochondrial genome differentiation and revealed weak linkage disequilibrium (LD) exclusively between O3+4 inversion arrangement and mitochondrial DNA haplotype I in two populations. In addition, the trend in the LD between OST chromosomal arrangement and haplotype II was general in the total sample. Microsatellite analysis revealed an absence of stochastic processes, like census reduction, upon population differentiation. Only a small amount of the genetic variation is related to geographic distance, while most (97%) is attributable to other factors and in some degree to microhabitat variables (temperature, humidity). The analysis of these factors revealed they effect inversion arrangement frequencies, especially E1+2+9, EST and OST. Even though this model organism is known for its high mobility and mostly large effective population size, the results presented here reveal that local adaptations can occur even at a small spatial scale. We propose that locally adapted alleles within chromosomal inversions, as well as joint selective pressures acting on mitochondrial and nuclear genomes, are responsible for the observed adaptation to microhabitat conditions

Hydroxyapatite nano particles doped with Gd3+, Yb3+/Tm3+ and Eu3+ as lumino-magnetic multimodal contrast agents

Hydroxyapatite (HAp) has been widely used as bone reconstruction materials due to their similarity to bone tissue. The improvement of HAp properties was achieved by doping its crystal lattice with different ions. Lanthanides, i.e. Rare Earth Elements (RE) are also suitable for doping HAp. The aim of the presented research was to investigate the possibility of creating lumino-magnetic particles of HAp doped with gadolinium (Gd3+) ions and co-doped with ytterbium/thulium (Yb3+/Tm3+) or europium (Eu3+) ions for potential use in multimodal imaging (MI). Pure HAp (Ca5(PO4)3(OH)), magnetic HAp:Gd (Ca4.85Gd0.15(PO4)3(OH)), and lumino-magnetic HAp:Gd/Yb/Tm (Ca4.85Gd0.03Yb0.1Tm0.02(PO4)3(OH)) and HAp:Gd/Eu (Ca4.94Gd0.02Eu0.04(PO4)3(OH)) particles were synthesized using emulsification process and hydrothermal processing. All synthesized particles had an elongated shape and exhibited a paramagnetic behavior. Reduction of the unit cell volume as a result of replacement of Ca2+ ions by ions with a smaller ionic radius (Gd3+, Yb3+, Tm3+, Eu3+) confirmed by using XRD and Rietveld refined plots. The energy band gap values of the synthesized samples range from 4.93 to 3.18 eV and decrease in the following order: HAp:Gd >HAp>HAp:Gd/Eu>HAp:Gd/Yb/Tm. The results of photoluminescence emission spectra of HAp:Gd/Yb/Tm and HAp:Gd/Eu particles showed characteristic transitions of Tm3+ and Eu3+, respectively

Synergistic effect of environmental and genomic stress on wing size of drosophila subobscura

Growing anthropogenic influence on every aspect of environment arise important issues regarding the ability of populations and species to adapt to variant pressures. Lead is one of the most present contaminants in the environment with detrimental influence on organisms and populations. In combination with genomic stress, lead may act synergistically, leading to reduction in adaptive values. We sampled two Drosophila subobscura populations, from ecologically different habitats and established differences in genetic backgrounds and population histories. In order to establish different levels of genome heterozygosity, series of intra-line, intra-population and between population crosses were made. The progeny was reared on a standard Drosophila medium and a medium with 200μg/mL of lead acetate and right wing of approximately 4000 individuals was used for geometric morphometric analysis of wing size. Results showed that lead significantly reduces wing size and that magnitude of this reduction is dependent on genetic background, indicating synergistic effect of genomic and environmental stress. There is also an indication of strong female origin influence on the outcome of hybridization when source of environmental stress is lead. Our results showed that the genetic structure of populations is of great importance for population fitness in anthropogenic induced stressful conditions. Further studies of synergistic effect of genetic and environmental stress are needed, as well as studies of its outcome in natural populations.Genetika (2016), 48(3): 1039-105