Publications by authors named "Natasa Todorovic"

Studying the membrane physiology of filamentous fungi is key to understanding their interactions with the environment and crucial for developing new therapeutic strategies for disease-causing pathogens. However, their plasma membrane has been inaccessible for a micron-sized patch-clamp pipette for pA current recordings due to the rigid chitinous cell wall. Here, we report the first femtosecond IR laser nanosurgery of the cell wall of the filamentous fungi, which enabled patch-clamp measurements on protoplasts released from hyphae.

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Ion channels are vital components of filamentous fungi signaling in communication with their environment. We exploited the ability of the apical region of growing sporangiophores of Phycomyces blakesleeanus to form membrane-enveloped cytoplasmic droplets (CDs), to examine ion currents in the filamentous fungi native plasma membrane. In hypoosmotic conditions, the dominant current in the CDs is ORIC, an osmotically activated, anionic, outwardly rectified, fast inactivating instantaneous current that we have previously characterized.

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Studies of ion currents in filamentous fungi are a prerequisite for forming a complete understanding of their physiology. Cytoplasmic droplets (CDs), obtained from sporangiophores of Phycomyces blakesleeanus, are a model system that enables the characterization of ion currents in the native membrane, including the currents mediated by the channels not yet molecularly identified. Osmotically activated anionic current with outward rectification (ORIC) is a dominant current in the membrane of cytoplasmic droplets under the conditions of hypoosmotic stimulation.

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The research presented in this paper aims to investigate the performance of several newly synthesized ionic liquids during Pb/Bi detection in water on a liquid scintillation spectrometer Quantulus 1220 via Cherenkov counting. These experiments have been triggered by the recent reports that certain ionic liquids can act as wavelength shifters, thus significantly increasing the detection efficiency of Cherenkov radiation. The benefit of ionic liquid's addition to the analysed samples is reflected in the detection limit's decrement during Pb quantification, which is pertinent considering naturally low levels of Pb in aqueous samples.

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In this work, the radon emanation coefficients for selected building materials that are most often used in Serbia for covering floor surfaces (concrete, concrete screed, granite, glazed ceramic tiles, marble, roofing tile, and terrazzo tile) were determined, and the influence of the material structure on their values. The concentration ofRa activity in the samples was determined using the gamma spectrometry method. Radon emanation was measured with the RAD7 device.

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In this study, the results of research on radon activity concentrations in natural mineral waters, traditionally used for drinking but also for other needs, in rural and urban households in northern Kosovo are presented. Radon activity concentration in water was measured by the alpha spectrometric method with a RAD7 device. Radon activity concentrations in the 24 waters studied ranged from 1.

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We report the utilization of Third-Harmonic Generation microscopy for label-free live cell imaging of lipid droplets in the hypha of filamentous fungus Phycomyces blakesleeanus. THG microscopy images showed bright spherical features dispersed throughout the hypha cytoplasm in control conditions and a transient increase in the number of bright features after complete nitrogen starvation. Colocalization analysis of THG and lipid-counterstained images disclosed that the cytoplasmic particles were lipid droplets.

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The accumulation of the radioactive gas radon in closed environments, such as dwellings, is the result of a quite complex set of processes related to the contribution of different sources. As it undergoes different physical mechanisms, all occurring at the same time, models describing the general dynamic turns out to be difficult to apply because of the dependence on many parameters not easy to measure or calculate. In this context, the authors developed, in a previous work, a simplified approach based on the combination of a physics-mathematical model and on-site experimental measurements.

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Reliable determination of Ra content in drinking water, surface water and groundwater is required for radiological health-risk assessment of populations and radiation-dose calculations after ingestion and inhalation. This study aimed to determine Ra presence in the untreated water samples on a liquid scintillation counter via Cherenkov radiation detection. Cherenkov counting is a faster, simpler, less expensive technique than other commonly used methods for Ra determination.

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Assessment of radiation exposure to drinking, surface, and groundwater and of the associated health risks calls for accurate and precise Ra and Rn measurements. One method that fits the bill is liquid scintillation counting (LSC), which allows measurements in one-phase (homogenous) or two-phase samples. The aim of our study was to compare the measurement efficiency with both variations in Niška Banja spa water, known for its elevated Rn content to get a better insight into the stability and behaviour of the samples and Ra interference in samples spiked with Ra with Rn measurement.

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This retrospective study provides an insight into the levels of radiation exposure of six nuclear medicine (NM) staff (four technologists and two nurses) performing routine diagnostic F-fluorodeoxyglucose (F-FDG) positron emission tomography-computed tomography (PET/CT) at the University Clinical Centre of the Republic of Srpska, Department of Nuclear Medicine and Thyroid Disorders, Banja Luka, Bosnia and Herzegovina. Data analysis included monthly staff exposure measured with personal thermoluminescent dosimeters (TLD) between June and December 2018, quantified in terms of normalised dose for the whole body [Hp(10)] and dominant hand [Hp(0.07)] and their comparison between each staff member and between the two groups (technologists and nurses).

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Background: The objective of this study was to assess the complex relationship between the multiple determinants of the caregiving process, the caregiver burden, and depression during the COVID-19 pandemic in Serbia.

Methods: A cross-sectional study was conducted on a nationally representative sample (n = 798) during the COVID-19 pandemic in Serbia from March to September 2020. A nine-section questionnaire designed for this study included the characteristics of caregivers, characteristics of care and care recipients, COVID-19 related questions, and the following standardized instruments: 12-Item Short-Form Health Survey, Fatigue Severity Scale, Activities of Daily Living Scale and Instrumental Activities of Daily Living Scale, Zarit Caregiver Burden Scale, and Beck Depression Inventory.

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Two newly synthesized 4-hydroxycoumarin bidentate ligands (L1 and L2) and their palladium(II) complexes (C1 and C2) were screened for their biological activities, and . Structures of new compounds were established based on elemental analysis, H NMR, C NMR, and IR spectroscopic techniques. The obtained compounds were tested for their antioxidative and cytotoxic activities and results pointed to selective antiradical activity of palladium(II) complexes towards OH and OOH radicals and anti-ABTS (2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical) activity comparable to that of ascorbate.

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Possible application of a novel ionic liquid 3-methylpiridinium salicylate (3-MPS) in Liquid Scintillation Counting measurements has been explored. Its addition to several radionuclides' aqueous solutions shown a significant influence on Pb Cherenkov spectra, Pb and Ra gross alpha/beta spectra, even on H spectra appearance. 3-MPS manifested both wavelength shifting and scintillating effect, indicating that 3-MPS or other ionic liquids of similar structure soon might be implemented into the common LSC practise as an alternative to the commercial LSC cocktails.

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In this paper, phosphogypsum (PG) with the content of Ra of about 500 Bq kg was used as a clay additive in mass ratios of (0-40) % and its influence on the radiological and mineralogical characteristics of the obtained brick samples was monitored. After sintering the samples at 1000 ℃, the formation of the mineral phase gehlenite was observed, and its share increased with the share of PG in the samples. The Monte Carlo method was used to determine the gamma dose rates, and consequently annual effective dose, for a standard room, with dimensions 4 × 5 × 2.

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Article Synopsis
  • The COVID-19 pandemic increased the reliance on informal caregivers in Serbia, prompting a study on their quality of life during this period.
  • A cross-sectional study involving 112 caregivers assessed their physical and mental health using surveys and interviews, revealing that most caregivers were middle-aged females caring for family members.
  • Findings indicated that caregivers faced negative health outcomes, with physical health impacted by care complexity, and mental health affected by worries about themselves and the individuals they care for amid the pandemic.
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Space manifolds act as the boundaries of dynamical channels enabling fast transportation into the inner- and outermost reaches of the Solar System. Besides being an important element in spacecraft navigation and mission design, these manifolds can also explain the apparent erratic nature of comets and their eventual demise. Here, we reveal a notable and hitherto undetected ornamental structure of manifolds, connected in a series of arches that spread from the asteroid belt to Uranus and beyond.

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Paper presents results of researches carried out on various locations and immediate vicinity of mining and industrial activities of the northern and south-eastern part of Kosovo. Concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Rn-222, as well as temperature and pH values of natural spring water were measured at 15 measuring sites (that belong to Zvečan, Leposavić and Novo Brdo municipalities), in April-May and September-October 2019. The quantification of heavy metals' content was performed by applying ICP-OES method.

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Monitoring of Rn in drinking or surface waters, as well as in groundwater has been performed regularly in connection with geological, hydrogeological and hydrological surveys and health hazard studies. Liquid scintillation counting (LSC) is often preferred analytical method for Rn measurements in waters as it allows multiple-sample automatic analysis. LSC method implies mixing of water samples with organic scintillation cocktail, which triggers radon diffusion from the aqueous into an organic phase for which it has a much greater affinity, eliminating the possibility of radon emanation in that manner.

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The development of new methods and improvements of existing methods for the specific activity determination of Sr and other distinct beta emitters has been of considerable interest. The reason for this interest is that the notably small number of methods that are able to meet all the set criteria, such as reliability of the results, measurement uncertainty and time, and minimum production of radioactive waste, as well as applicability to various samples with reference to their nature, geometry and composition. In this paper, two methods for rapid Sr activity determination based on Monte Carlo simulations are used, one for a Si semiconductor detector for beta spectrometric measurements and the other for the Geiger-Muller (GM) ionization probe.

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Studies have been carried out to determine the natural radioactivity in some materials used in ceramic industry (zircon, zirkosil, Zircobit MO/S, zircon silicate, zirklonil frit, hematite, bentonite, wollastonite, raw kaolin, kaolinized granite, sileks ball, feldspar, pigment, white base serigraphic, engobe) and their associated radiation hazard. The external hazard index, Hex, values, radium equivalent activity, Raeq, total absorbed dose rates, D and annual effective dose, De were derived for all measured materials and compared with the recommended values to assess the external radiation hazards to workers who worked in ceramic industries in Serbia.

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Gross alpha/beta activity determination is utilized as a very popular Liquid Scintillation Counting (LSC) technique widely used in routine monitoring of drinking, surface and waste waters. Since quenching phenomena are most problematic effect during LSC measurements, the objectives of this paper are to present, consider and evaluate two methods for color quench correction as a proposal for supplement to the ASTM D 7283-06 method for gross α/β determination. The first method is PSA adjustment: application of previously established dependence of optimal PSA discriminator between alpha and beta events on quench level of sample.

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A procedure for the determination of Sr in environmental water samples using Čerenkov radiation and low-level liquid scintillation counter Quantulus 1220 was applied and optimized. Low diffusion polyethylene vials, high performance glass counting vials and low potassium borosilicate glass vilas of 20 ml volume (all from PerkinElmer) were used in order to examine their potential effect on counting process. The derived efficiencies were 45.

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Increasing resistance of fungal strains to known fungicides has prompted identification of new candidates for fungicides among substances previously used for other purposes. We have tested the effects of known anion channel inhibitors anthracene-9-carboxylic acid (A9C) and niflumic acid (NFA) on growth, energy metabolism and anionic current of mycelium of fungus Phycomyces blakesleeanus. Both inhibitors significantly decreased growth and respiration of mycelium, but complete inhibition was only achieved by 100 and 500 µM NFA for growth and respiration, respectively.

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Activity concentrations of Ra, Th and K in 120 kaolinized granite samples imported in Serbia from the Motajica mine, Bosnia and Herzegovina, were measured. The Ra concentration ranged from 61 to 319 Bq kg, the Th from 44 to 272 Bq kg, and the K from 590 to 1470 Bq kg. The frequency distribution of K concentrations was near-Gaussian, where those of Ra and Th were right-skewed.

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