المؤلفون: Dimitrijevic, Ivan, Dragovich, Branko, Rakic, Zoran, Stankovic, Jelena

مصطلحات موضوعية: Physics - General Physics

الوصف: It is already known that a simple nonlocal de Sitter gravity model, which we denote as $\sqrt{dS}$ gravity, contains an exact vacuum cosmological solution which mimics dark energy and dark matter and is in very good agreement with the standard model of cosmology. This success of $\sqrt{dS}$ gravity motivated us to investigate how it works at lower than cosmic scale -- galactic and the solar system. This paper contains our investigation of the corresponding Schwarzschild-de Sitter metric of the $\sqrt{dS}$ gravity model. To get exact solution, it is necessary to solve the corresponding nonlinear differential equation, what is a very complicated and difficult problem. What we obtained is a solution of linearized equation, which is related to space metric far from the massive body, where gravitational field is weak. The obtained approximate solution is of particular interest for examining the possible role of non-local de Sitter gravity $\sqrt{dS}$ in describing the effects in galactic dynamics that are usually attributed to dark matter. The solution has been tested on the Milky Way and the spiral galaxy M33 and is in good agreement with observational measurements.
Comment: 18 pages, 3 figures

الوصول الحر: http://arxiv.org/abs/2404.05848Test

المؤلفون: Dimitrijevic, Ivan, Dragovich, Branko, Rakic, Zoran, Stankovic, Jelena

مصطلحات موضوعية: General Relativity and Quantum Cosmology

الوصف: In this paper, we briefly review highlights of nonlocal de Sitter gravity based on the nonlocal term $ \sqrt{R - 2\Lambda}\ \mathcal{F}(\Box)\ \sqrt{R - 2\Lambda }$ in the Einstein-Hilbert action without matter sector. This nonlocal de Sitter gravity model has several exact cosmological FLRW solutions and one of these solutions contains some effects that are usually assigned to dark matter and dark energy. There are also some other interesting and promising properties of this kind of gravity nonlocality. We also review some anisotropic cosmological solutions, and mention the corresponding nonlocal Schwarzschild-de Sitter metric.
Comment: arXiv admin note: text overlap with arXiv:2206.13515

الوصول الحر: http://arxiv.org/abs/2312.16673Test

المؤلفون: Dimitrijevic, Ivan, Dragovich, Branko, Rakic, Zoran, Stankovic, Jelena

مصطلحات موضوعية: General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Theory

الوصف: This paper is devoted to a simple nonlocal de Sitter gravity model and its exact vacuum cosmological solutions. In the Einstein-Hilbert action with $\Lambda$ term, we introduce nonlocality by the following way: $R - 2 \Lambda = \sqrt{R-2\Lambda}\ \sqrt{R-2\Lambda} \to \sqrt{R-2\Lambda}\ F(\Box)\ \sqrt{R-2\Lambda} ,$ where ${F} (\Box) = 1 + \sum_{n= 1}^{+\infty} \big( f_n \Box^n + f_{-n} \Box^{-n} \big) $ is an analytic function of the d'Alembert-Beltrami operator $\Box$ and its inverse $\Box^{-1}$. By this way, $R$ and $\Lambda$ enter with the same form into nonlocal version as they are in the local one, and nonlocal operator $F(\Box)$ is dimensionless. The corresponding equations of motion for gravitational field $g_{\mu\nu}$ are presented. The first step in finding some exact cosmological solutions is solving the equation $\Box \sqrt{R-2\Lambda} = q \sqrt{R-2\Lambda} , $ where $ q =\zeta \Lambda \quad (\zeta \in \mathbb{R})$ is an eigenvalue and $\sqrt{R-2\Lambda}$ is an eigenfunction of the operator $\Box .$ We presented and discussed several exact cosmological solutions for homogeneous and isotropic universe. One of these solutions mimics effects that are usually assigned to dark matter and dark energy. Some other solutions are examples of the nonsingular bounce ones in flat, closed and open universe. There are also singular and cyclic solutions. All these cosmological solutions are a result of nonlocality and do not exist in the local de Sitter case.
Comment: 27 pages, 5 figures. Comments welcome

الوصول الحر: http://arxiv.org/abs/2206.13515Test

المؤلفون: Dimitrijevic, Ivan, Dragovich, Branko, Rakic, Zoran, Stankovic, Jelena

المصدر: Symmetry 2022, 14, 3

مصطلحات موضوعية: General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Theory

الوصف: A nonlocal gravity model (2.1) was introduced and considered recently [49], and two exact cosmological solutions in flat space were presented. The first solution is related to some radiation effects generated by nonlocal dynamics on dark energy background, while the second one is a nonsingular time symmetric bounce. In the present paper we investigate other possible exact cosmological solutions and find some the new ones in nonflat space. Used nonlocal gravity dynamics can change background topology. To solve the corresponding eqations of motion, we first look for a solution of the eigenvalue problem $\Box (R -4\Lambda) = q\ (R - 4\Lambda) .$ We also discuss possible extension of this model with nonlocal operator symmetric under $\Box \longleftrightarrow \Box^{-1}$ and its connection with another interesting nonlocal gravity model.
Comment: 18 pages, submitted to the journal Symmetry

الوصول الحر: http://arxiv.org/abs/2112.06312Test

المؤلفون: Božić, Dragana, Milenković, Marina, Antić-Stanković, Jelena, Arsenović-Ranin, Nevena, Bufan, Biljana

المصدر: Arhiv za farmaciju

مصطلحات موضوعية: human microbiota, dysbiosis, commensal bacteria, dysbiosis-associated diseases, humana mikrobiota, disbioza, komensalne bakterije, bolesti povezane sa disbiozom

الوصف: The normal human microbiota, formerly called the "microbial flora," consists of bacteria, fungi, viruses, and parasites that colonise the skin and mucous membranes of the respiratory, gastrointestinal, and genitourinary tracts. The number and diversity of microorganisms varies between different body niches and is greatest in the intestinal tract. The microbiota contributes to the homeostasis of the human organism by preventing colonisation by pathogenic microorganisms, participating in digestive processes and metabolism, and regulating immune functions. Various environmental and genetic factors can lead to an imbalance in the human microbiota, called dysbiosis, which can affect human health. Dysbiosis is usually the result of decreased microbial diversity and a lower number of saprophytic microorganisms, followed by an overgrowth of opportunistic species. The most common diseases directly related to intestinal dysbiosis are antibiotic-associated diarrhoea and pseudomembranous colitis, both of which are associated with the excessive growth of harmful bacteria and Clostridioides difficile following broad-spectrum antibiotic therapy. Dysbiosis is associated with various health conditions or diseases such as acne, psoriasis, eczema, chronic obstructive pulmonary disease, inflammatory bowel disease, obesity, metabolic syndrome, type 2 diabetes, autoimmune diseases and allergies, neurological diseases such as Parkinson's disease, Alzheimer's disease, epilepsy and stroke, depression, anxiety, infertility, preterm birth, and malignancies. ; Normalna ljudska mikrobiota, koja se ranije nazivala „mikroflora“, sastoji se od bakterija, gljivica, virusa i parazita koji kolonizuju kožu i sluzokožu respiratornog, gastrointestinalnog i genitourinarnog trakta. Broj i raznovrsnost mikroorganizama variraju između različitih telesnih niša i najveći su u crevnom traktu. Mikrobiota doprinosi homeostazi ljudskog organizma tako što sprečava kolonizaciju patogenim mikroorganizmima, učestvuje u procesima varenja i metabolizma i reguliše ...

العلاقة: https://farfar.pharmacy.bg.ac.rs/handle/123456789/5582Test; http://farfar.pharmacy.bg.ac.rs/bitstream/id/15752/Normal_human_microbiota_pub_2024.pdfTest

الإتاحة: https://doi.org/10.5937/arhfarm74-46612Test
https://farfar.pharmacy.bg.ac.rs/handle/123456789/5582Test
http://farfar.pharmacy.bg.ac.rs/bitstream/id/15752/Normal_human_microbiota_pub_2024.pdfTest

المؤلفون: Stanković, Jelena, Milošević, Đurađ, Paunović, Momir, Jovanović, Boris, Popović, Nataša, Tomović, Jelena, Atanacković, Ana, Radulović, Katarina, Lončarević, Davor, Raković, Maja

المصدر: Water

مصطلحات موضوعية: microplastic, pollution, Danube River, macroinvertebrates, μFTIR spectroscopy

الوصف: This study was carried out at the Danube River and its tributaries during the Joint Danube Survey 4 (JDS4) expedition. Three freshwater benthic species were used to estimate the quantity of microplastics (MPs): Corbicula spp., Limnodrilus hoffmeisteri (Claparede, 1862), and Polypedilum nubeculosum (Meigen, 1804). Following the kick and sweep technique, individuals were sampled using a hand net or dredge. In order to estimate the number of MP particles/individual particles/g wet body mass, the body mass and total length of all specimens were measured. Alkaline (Corbicula spp. and L. hoffmaisteri) and enzymatic (P. nubeculosum) protocols were performed for tissue degradation. All samples were filtered through glass microfiber filters (mesh size 0.5 μm). The particles were photographed, measured, and counted. A total of 1904, 169, and 204 MPs were isolated from Corbicula spp., L. hoffmaisteri, and P. nubeculosum, respectively. To confirm the chemical composition of isolated MPs, a subsample of 46 particles of the fragmented particles from 14 sampling sites was analysed via μ-ATR-FTIR spectroscopy analysis. The particles were characterised as polycarbonate (PC), polyethylene terephthalate (PET), polypropylene–polyethylene copolymer (PP-PE), nylon (polyamide-PA) and cellophane, with the domination of PET.

العلاقة: info:eu-repo/grantAgreement/MESTD/inst-2020/200007/RS//; http://radar.ibiss.bg.ac.rs/handle/123456789/6635Test; https://radar.ibiss.bg.ac.rs/bitstream/id/17189Test/Stankovic et al. 2024_Water _ Microplastic in the Danube River.pdf

الإتاحة: https://doi.org/10.3390/w16070962Test
http://radar.ibiss.bg.ac.rs/handle/123456789/6635Test
https://radar.ibiss.bg.ac.rs/bitstream/id/17189Test/Stankovic et al. 2024_Water _ Microplastic in the Danube River.pdf

المؤلفون: Sebteoui, Khouloud, Milošević, Djuradj, Stanković, Jelena, Baranov, Viktor, Jovanović, Boris, Krause, Stefan, Csabai, Zoltán

المساهمون: H2020 Marie Skłodowska-Curie Actions, University of Niš

المصدر: Science of The Total Environment ; volume 919, page 170844 ; ISSN 0048-9697

مصطلحات موضوعية: Pollution, Waste Management and Disposal, Environmental Chemistry, Environmental Engineering

الإتاحة: https://doi.org/10.1016/j.scitotenv.2024.170844Test
https://api.elsevier.com/content/article/PII:S0048969724009835?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0048969724009835?httpAccept=text/plainTest

المؤلفون: Dimitrijevic, Ivan, Dragovich, Branko, Rakic, Zoran, Stankovic, Jelena

المصدر: Springer Proceedings in Mathematics & Statistics 263, 91-111 (2018)

مصطلحات موضوعية: High Energy Physics - Theory, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology

الوصف: We consider nonlocal modified Einstein gravity without matter, where nonlocal term has the form $P(R) F(\Box) Q(R)$. For this model, in this paper we give the derivation of the equations of motion in detail. This is not an easy task and presented derivation should be useful to a researcher who wants to investigate nonlocal gravity. Also, we present the second variation of the related Einstein-Hilbert modified action and basics of gravity perturbations.
Comment: 22 pages

الوصول الحر: http://arxiv.org/abs/1902.08820Test

المؤلفون: Katanić Stanković, Jelena S., Todorović, Violeta, Đorović Jovanović, Jelena, Marković, Zoran, Krstić, Sanja, Dabetić, Nevena, Šobajić S., Bartoszek, Agnieszka, Maksimović, Zoran, Bauer, Rudolf

مصطلحات موضوعية: Theobroma cacao L, cocoa powder, inflammation, anti-inflammatory activity, in vitro, in silico

الوصف: Plants are considered the major sources of biologically active compounds, which provide unlimited opportunities for their use either as medical treatments or as novel drug formulations. Cocoa powder is frequently used in nutrition and is known to have many benefits thanks to its wide range of biological activities. The presented study was focused on the evaluation of the anti-inflammatory potential of extracts obtained from cocoa powder. In vitro assays were employed to evaluate the level of inhibition of cyclooxygenases-1 and -2 activities (COX-1 and COX-2) by tested extracts. Molecular docking was used for in silico prediction of cyclooxygenase isoforms inhibition by selected cocoa powder constituents. The results showed that all tested extracts exerted much higher potential in inhibiting COX-2 activity and may be considered in use as selective inhibitors of COX-2 enzyme. On the other hand, in silico study shows quercetin and clovamide as the compounds with the highest potential to inhibit both COX-1 and COX-2. ; Published

وصف الملف: application/pdf

العلاقة: 2nd International Conference on Chemo and BioInformatics; https://scidar.kg.ac.rs/handle/123456789/19266Test

الإتاحة: https://doi.org/10.46793/ICCBI23.156KSTest
https://scidar.kg.ac.rs/handle/123456789/19266Test

المؤلفون: Jevremovic A., Milivojević J., Katanić Stanković, Jelena S., Popović-Đorđević, Jelena

مصطلحات موضوعية: raspberry fruit, "Willamette", "Meeker", soil, bioaccumulation

الوصف: Raspberry (Rubus idaeus L.) is the most important type of berry fruit in the Republic of Serbia. The bioaccumulation factor (BF) for the elements detected in the fruits of the raspberry cultivars 'Willamette' and 'Meeker' was calculated to determine their bioaccumulation potential. In addition, the nutritional quality of fruits in relation to nutritionally essential elements was evaluated and compared with the recommended daily intake. For determining the concentrations of 19 macro- and microelements in fruits and the soil, the analytical technique of optical emission spectrometry with inductively coupled plasma was used. Among the analyzed elements, As, Cd, Co, Cr, Li and Mo were below the limit of detection in the fruits of both raspberry cultivars, whereas Na and Ni were detected only in fruits of the 'Meeker' cultivar. All analyzed elements were detected in the soil. The results of the work indicated the high potential of the studied cultivars to accumulate nutritional elements K and Ca. In both raspberry cultivars, there were no substantial differences in the bioaccumulation of most elements. However, two elements (B and Mn) can be singled out; the BF for B in the 'Willamette' fruit was 3 times lower compared to the BF in the 'Meeker' fruit, whereas the BF value for Mn in the 'Willamette' fruit was almost 8 times higher compared to the BF value for the 'Meeker' fruit. Furthermore, the cultivars did not tend to accumulate potentially toxic elements such as Ba, Co, Cu and Ni. The nutritional evaluation revealed that the studied raspberry fruits are a good source of K, Ca, Mg, Fe, Mn and Cu. Based on the BF values, differences observed in the accumulation ; Published

وصف الملف: application/pdf

العلاقة: 2nd International Conference on Chemo and BioInformatics; https://scidar.kg.ac.rs/handle/123456789/19262Test

الإتاحة: https://doi.org/10.46793/ICCBI23.152JTest
https://scidar.kg.ac.rs/handle/123456789/19262Test