Ekotoksičnost nanočestica oksida metala i potencijalne metode za njihov biomonitoring u akvatičnim ekosistemima

This research deals with ecotoxicity of insoluble metal oxide nanoparticles, that deposit at the bottom of aquatic ecosystems and therefore influence the hydrobiocenosis community: titanium dioxide nano-TiO2 (used as a food colour), cerium oxide nano-CeO2 (used in the automotive industry) and iron oxide nano-Fe3O4 (magnetic particles manufactured for medicinal use). Detailed characterisation of examined nanoparticles was conducted through contemporary analytical methods (for the analysis of specific surface-BET; surface chemistry-XPS; phase and crystal structure-XRD; size, aggregation and sample photographing-TEM, SEM and AFM; qualitative and quantitative element analysis-EDX; hydrodynamic diameter, polydispersity index and ζ-potential-DLS; in situ nanoparticle characterisation in the experimental sediment-EDX and SEM). Multiparametric bioassays were conducted, according to the OECD protocol, on aquatic model organisms: Chironomidae (Diptera): Chironomus tentans and Chironomus riparius. A series of standard (mortality, survival rate, developmental time and rate and emergence delay), as well as nonstandard biomarkers were analysed (oxidative stress-lipid and protein oxidation, SOD and CAT activity, expressed by total protein content; in vivo genotoxicity via DNA damage analysis; haemoglobin concentration; morphological variability change). For the first time in known literature geometric morphometric method was used for comprehensive nanoparticle toxicity analysis. Bioaccumulation of all tested nanoparticles by model organisms has been proven. The sublethal toxicity of titanium, cerium and iron oxide nanoparticles was determined, while in the case of nano-TiO2, a lethal effect was observed as well. Modified OECD protocol number 218 that implies using C. riparius as model organism, fine quartz sand substrate, detailed nanoparticle characterization, bioaccumulation analysis, analysis of standard and complementary sublethal biomarkers, enables efficient assessment of toxicity and monitoring of nanoparticles in aquatic ecosystems

Ekotoksičnost nanočestica oksida metala i potencijalne metode za njihov biomonitoring u akvatičnim ekosistemima

This research deals with ecotoxicity of insoluble metal oxide nanoparticles, that deposit at the bottom of aquatic ecosystems and therefore influence the hydrobiocenosis community: titanium dioxide nano-TiO2 (used as a food colour), cerium oxide nano-CeO2 (used in the automotive industry) and iron oxide nano-Fe3O4 (magnetic particles manufactured for medicinal use). Detailed characterisation of examined nanoparticles was conducted through contemporary analytical methods (for the analysis of specific surface-BET; surface chemistry-XPS; phase and crystal structure-XRD; size, aggregation and sample photographing-TEM, SEM and AFM; qualitative and quantitative element analysis-EDX; hydrodynamic diameter, polydispersity index and ζ-potential-DLS; in situ nanoparticle characterisation in the experimental sediment-EDX and SEM). Multiparametric bioassays were conducted, according to the OECD protocol, on aquatic model organisms: Chironomidae (Diptera): Chironomus tentans and Chironomus riparius. A series of standard (mortality, survival rate, developmental time and rate and emergence delay), as well as nonstandard biomarkers were analysed (oxidative stress-lipid and protein oxidation, SOD and CAT activity, expressed by total protein content; in vivo genotoxicity via DNA damage analysis; haemoglobin concentration; morphological variability change). For the first time in known literature geometric morphometric method was used for comprehensive nanoparticle toxicity analysis. Bioaccumulation of all tested nanoparticles by model organisms has been proven. The sublethal toxicity of titanium, cerium and iron oxide nanoparticles was determined, while in the case of nano-TiO2, a lethal effect was observed as well. Modified OECD protocol number 218 that implies using C. riparius as model organism, fine quartz sand substrate, detailed nanoparticle characterization, bioaccumulation analysis, analysis of standard and complementary sublethal biomarkers, enables efficient assessment of toxicity and monitoring of nanoparticles in aquatic ecosystems

Hospital infections rate and health staff density in a neonatology department

© 2017, Serbian Medical Society. All rights reserved. Objective. The aim of our study was to compare staffing trends for physicians and nurses with hospital infections (HIs) rate at a neonatology department of tertiary care health facility. Methods. The prospective cohort study was conducted at Neonatology Department, Clinical Centre Kragujevac, Serbia. The incidences of neonates with HIs were calculated for each of the quarters during the 5-year period. The data about the number and structure of staff for each quarter of the study period were collected from the official work schedule lists of the department. Results. This study registered a total of 272 HIs occurring in 264 neonates. The incidence rate of patients with HIs was 13.36% and the incidence density of HIs was 5.85 per 1,000 patient-days. In the observed period the trend of incidence rate of patients with HIs was stable, but the trend of incidence density of HIs was increasing, however without statistical significance. The highest incidence rates of patients with HIs were recorded in the third quarter of all observed years respectively: 17.44% in 2012, 16.74% in 2013, 23.47% in 2014, 18.18% in 2015 and 22.74 in 2016. The average number of nurses in the first shift ranged from 5.0 to 7.0, but in second shift was 3.0 to 4.0 only, and the least number of nurses worked in the third quarter of each year. The average number of physicians in the first shift ranged from 2.33 to 4.47 and they were also the fewest in numbers in the third quarter. We observed strong negative correlation between the average incidence rate of patients with HIs and the average number of nurses in the first shift (r=-0.977, p=0.023). Conclusion. Optimal nurse and physician staffing of neonatal departments in developing countries and the avoidance of inter-quarter variations in number of staff at duty would decrease the incidence of HIs and probably create overall savings of the hospital budget

Non-invasive approach in the treatment of temporomandibular joint osteoarthritis

Introduction Temporomandibular dysfunction (TMD) is a set of disorders that involve the masticatory muscles, the temporomandibular joint (TMJ), and its associated structures. Osteoarthritis (OA), as one of the forms of TMD, leads to permanent changes in the bone structures of TMJ. These changes can be the cause of serious functional disorders of the TMJ. Case outline This article describes a case of a 24-year-old female patient who sought help due to pain and swelling in the area of the right and left TMJ, accompanied by muscular tension, severe headaches, which did not respond to medication. Аfter establishing the diagnosis, we applied a therapy in the treatment of the bilateral OA of the TMJ, where we used non-invasive methods. Six months later, the patient reported the absence of pain, swelling, headache, and muscle tension in the orofacial region. Conclusion There is no “gold standard” for the management of ОА of ТМЈ. In our study, non-invasive therapy was successful in eliminating pain, increasing the range of motion of the lower jaw, stopping the progression of the disease, and advancing the quality of life

Mandibular shape as a proxy for the identification of functional feeding traits of midge larvae (Diptera: Chironomidae)

The identification of functional feeding traits in aquatic macroinvertebrates often requires a morphology-based identification of species, which is important for trait-based methods of biological assessment. The extent of functional homogenization is compared along scales of impairment, where trait-based information is used as an input in models that examine degradation pathways. However, trait-based information is not always readily available for all groups of aquatic insects, especially for species diverse families, such as chironomids (Diptera: Chironomidae). Taxonomic challenges and ambiguous traits complicate the use of chironomid larvae in trait-based bioassessment. Here, we examine the use of geometric morphometric analysis (GMA), deep learning (Convolutional Neural Networks), and computer vision (deep CNN) applied to the mouthparts (mandibles) of chironomid larvae as a proxy for identifying the relationship between the functional morphology and food acquisition behaviour. We determined the variability in morphology of mandibles for 23 taxa of chironomid larvae from different genera, subfamilies, and their Functional Feeding Group (FFG). Analysis using GMA showed that the five different FFGs examined had different mandibular traits that significantly varied in shape and size. A deep CNN model was then built that was able to classify the 23 taxa into their respective FFG automatically with 92.31 % accuracy. A gradient-weighted Class Activation Mapping (Grad-CAM) algorithm found that the most important part of mandibles for classification were the gula and mandibular joint. We introduced three additional species to the deep CNN models to test whether automatic classification would directly and automatically identify traits of the specimens independently from taxonomic identification. The deep CNN process avoids issues surrounding both taxonomic identification and previous knowledge of a specific taxon’s feeding trait, and in all cases the model classified taxa correctly based on their mandibular traits. The use of deep learning approaches could substantially enhance the use of trait-based approaches and increase the reliability and use of chironomids in bioassessment

Revealing the effects of cerium dioxide nanoparticles through the analysis of morphological changes in CHIRONOMUS RIPARIUS

Due to their many practical applications, engineered cerium dioxide (CeO2) nanoparticles (NPs) are commonly used today, although there are justified concerns about the environmental risks of their usage. Studies to date have shown that CeO2 NPs do not pose a lethal hazard to hydrobiocenoses at environmentally relevant concentrations, but that they induce significant negative sublethal effects. Therefore, intensive work is being done on the adaptation of standard ecotoxicological tests with the development of new, sublethal biomarkers. The present study aims to examine the sublethal effects of prolonged exposure to CeO2 NPs (2.5; 25; 250 and 2500 mg of CeO2 NPs per 1 kg of sediment) on the morphological features of the non-biting aquatic midge Chironomus riparius. Morphological variation was examined by means of two approaches: (1) Deformity rate analysis (analysis of visible morphological malformations) and (2) Geometric morphometric analysis (analysis of differences in the size and shape of the larval mandibles and mentums, as well as adult male and female wings). Changes in all the morphological structures examined were observed using a geometric morphometric approach at low and very high concentrations of CeO2 NPs (2.5 and 2500 mg of CeO2 NPs per 1 kg of sediment). The potential reduction of sexual dimorphism resulting from downsizing of the wings in females was observed. These results indicate that the sublethal changes observed in chironomids exposed to CeO2 NPs are significant and may potentially lead to further changes in metabolism, diet and behavior, which may lead to repercussions of as yet unexamined proportions. Considering our findings, and the advantages of geometric morphometrics (precision, uniformity, accurate qualification, quantification, and visualization of fine morphological changes), this approach is proven to be an exceptional assessment tool, with great applicative potential in the ecotoxicological testing of nanoparticles.This is a manuscript of an article published as Savić-Zdravković, Dimitrija, Djuradj Milošević, Jelena Conić, Katarina Marković, Janez Ščančar, Marko Miliša, and Boris Jovanović. "Revealing the effects of cerium dioxide nanoparticles through the analysis of morphological changes in CHIRONOMUS RIPARIUS." Science of The Total Environment (2021): 147439. doi:10.1016/j.scitotenv.2021.147439. Posted with permission.</p

Spectroscopy and polarimetry of the gravitationally lensed quasar SDSS J1004+4112 with the 6m SAO RAS telescope

© ESO 2020. Context. We present new spectroscopic and polarimetric observations of the gravitational lens SDSS J1004+4112 taken with the 6 m telescope of the Special Astrophysical Observatory (Russia). Aims. In order to explain the variability that is observed only in the blue wing of the C IV emission line, corresponding to image A, we analyze the spectroscopy and polarimetry of the four images of the lensed system. Methods. Spectra of the four images were taken in 2007, 2008, and 2018, and polarization was measured in the period 2014-2017. Additionally, we modeled the microlensing effect in the polarized light, assuming that the source of polarization is the equatorial scattering in the inner part of the torus. Results. We find that a blue enhancement in the C IV line wings affects component A in all three epochs. We also find that the UV continuum of component D was amplified in the period 2007-2008, and that the red wings of CIII] and C IV appear brighter in D than in the other three components. We report significant changes in the polarization parameters of image D, which can be explained by microlensing. Our simulations of microlensing of an equatorial scattering region in the dusty torus can qualitatively explain the observed changes in the polarization degree and angle of image D. We do not detect significant variability in the polarization parameters of the other images (A, B, and C), although the averaged values of the polarization degree and angle are different for the different images. Conclusions. Microlensing of a broad line region model including a compact outflowing component can qualitatively explain the C IV blue wing enhancement (and variation) in component A. However, to confirmed this hypothesis, we need additional spectroscopic observation in future

Revealing the effects of cerium dioxide nanoparticles through the analysis of morphological changes in CHIRONOMUS RIPARIUS

Due to their many practical applications, engineered cerium dioxide (CeO2) nanoparticles (NPs) are commonly used today, although there are justified concerns about the environmental risks of their usage. Studies to date have shown that CeO2 NPs do not pose a lethal hazard to hydrobiocenoses at environmentally relevant concentrations, but that they induce significant negative sublethal effects. Therefore, intensive work is being done on the adaptation of standard ecotoxicological tests with the development of new, sublethal biomarkers. The present study aims to examine the sublethal effects of prolonged exposure to CeO2 NPs (2.5; 25; 250 and 2500 mg of CeO2 NPs per 1 kg of sediment) on the morphological features of the non-biting aquatic midge Chironomus riparius. Morphological variation was examined by means of two approaches: (1) Deformity rate analysis (analysis of visible morphological malformations) and (2) Geometric morphometric analysis (analysis of differences in the size and shape of the larval mandibles and mentums, as well as adult male and female wings). Changes in all the morphological structures examined were observed using a geometric morphometric approach at low and very high concentrations of CeO2 NPs (2.5 and 2500 mg of CeO2 NPs per 1 kg of sediment). The potential reduction of sexual dimorphism resulting from downsizing of the wings in females was observed. These results indicate that the sublethal changes observed in chironomids exposed to CeO2 NPs are significant and may potentially lead to further changes in metabolism, diet and behavior, which may lead to repercussions of as yet unexamined proportions. Considering our findings, and the advantages of geometric morphometrics (precision, uniformity, accurate qualification, quantification, and visualization of fine morphological changes), this approach is proven to be an exceptional assessment tool, with great applicative potential in the ecotoxicological testing of nanoparticles

Changes in the wing shape and size in Drosophila melanogaster treated with food grade titanium dioxide nanoparticles (E171) – a multigenerational study

Drosophila is among the most commonly use models for toxicity assessment of different types of nanoparticles. This study aims to examine the effects of a constant exposure to the low concentration of human food grade titanium dioxide nanoparticles (TiO2 E171) on Drosophila melanogaster wing morphology over multiple generations. Subsequently, the Geometric Morphometrics Analysis was employed to examine possible changes in the wing shape and size of the treated flies. The treatment resulted in the diminishment but not a disruption in the sexual dimorphism in wings. Consequently, the female flies were clearly separated from the male flies by the differences in wing morphology as in the control group. A splitting by generations was overly similar within the control and the treatment, but it was slightly more pronounced in the treatment. However, the observed generational differences seemed mostly random between generations, irrespective of the treatment. Specifically, the treated groups displayed slightly higher splitting by generations in females than in males. Regardless of the generation, the results show a clear splitting by the differences in the wing shape between the treated flies and the flies from control. The mean value of centroid size, which refers to the wing size, of both female and male wings was smaller in the treatment when compared to the control. The overall effect of TiO2 was to induce significant difference in Drosophila wing morphology but it did not alter the general wing morphology pattern. Therefore, the change in the wings occurred only within the normally allowed wing variation.This is a manuscript of an article published as Cvetković, Vladimir J., Boris Jovanović, Maja Lazarević, Nikola Jovanović, Dimitrija Savić-Zdravković, Tatjana Mitrović, and Vladimir Žikić. "Changes in the wing shape and size in Drosophila melanogaster treated with food grade titanium dioxide nanoparticles (E171)–a multigenerational study." Chemosphere (2020). doi: 10.1016/j.chemosphere.2020.127787. Posted with permission.</p

Hospital acquired pneumonia in newborns with birth weight less than 1500 grams: Risk factors and causes

© 2016, University of Kragujevac, Faculty of Science. All rights reserved. Low birth weight newborns (1500 grams) are at a high risk of acquiring hospital infections due to the immaturity of the immune system, lack of efficient structural barriers, and an incomplete development of endogenous microbial flora. e aim of this study was to reveal the potential risk factors for hospital-acquired pneumonia in low birth weight newborns. is study was a prospective cohort design with a nested case-control study and was conducted between January 1st, 2012 and June 30th, 2015 at the Neonatology Department, Clinical Centre Kragujevac, Serbia. ere were 1140 newborns hospitalized at the Neonatology Department for longer than 48 hours during the study period, and 169 of them (14.82%) weighed less than 1500 grams at birth. In total, 73 (43.19%) newborns with low birth weights developed HIs. e most prevalent HI was hospital pneumonia (n=64, 87.67%). Although univariate analyses identified many risk factors with a significant influence on the occurrence of hospital pneumonia, multivariate analysis identified only the following two independent risk factors for hospital pneumonia in newborns with birth weights below 1500 grams: mechanical ventilation (p=0.003, OR=68.893, 95% CI=4.285-1107.699) and longer hospitalization (p=0.003, OR=1.052, 95% CI=1.017-1.088). Almost all of the pathogens isolated from the patients with pneumonia were gram-negative bacteria (98.50%). More than half of all of the isolates were Acinetobacter spp (37.50%) and Enterobacter spp (18.75%). Our study showed that mechanical ventilation and prolonged hospitalization were significant risk factors for the development of hospital pneumonia in newborns with birth weights below 1500 grams