TY  - CHAP
AU  - Jelić, Aleksandra
AU  - Božić, Aleksandra
AU  - Stamenović, Marina
AU  - Sekulić, Milica
AU  - Porobić, Slavica
AU  - Dikić, Stefan
AU  - Putić, Slaviša
AU  - Mitrović, Nenad
AU  - Mladenović, Goran
AU  - Mitrović, Aleksandra
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9636
AB  - Halloysite nanotubes (HNTs), naturally occurring as aluminosilicate nanoclay mineral, have recently emerged as a possible nanomaterial for countless applications due to their specific chemical structure, tubular shape, high aspect ratio, biocompatibility and low toxicity. In this study, HNTs were incorporated into the epoxy resin matrix to improve its mechanical properties and thermal stability. However, heterogeneous size, surface charge and surface hydrogen bond formation, result in aggregation of HNTs in epoxies to a certain extent. Three specific techniques were used to integrate HNTs into neat epoxy resin (NE). The structure and morphology of the embedded nanotubes were confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Tensile testing was carried out and the fractured surface of the tested specimen was analysed using scanning electron microscopy (SEM). The thermal stability of the prepared nanocomposite materials was investigated by thermogravimetric (TG) and derivative thermogravimetry (DTG) studies. The obtained results indicated that improved properties of HNTs/epoxy nanocomposite materials were related to the unique properties of well-dispersed HNTs, agglomerate scale, and reduced void presence, and could be controlled by the manufacturing processes.
PB  - Springer International Publishing
T2  - Experimental and Computational Investigations in Engineering
T1  - Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials
SP  - 310
EP  - 325
DO  - 10.1007/978-3-030-58362-0_18
ER  - 

@inbook{
author = "Jelić, Aleksandra and Božić, Aleksandra and Stamenović, Marina and Sekulić, Milica and Porobić, Slavica and Dikić, Stefan and Putić, Slaviša and Mitrović, Nenad and Mladenović, Goran and Mitrović, Aleksandra",
year = "2021",
abstract = "Halloysite nanotubes (HNTs), naturally occurring as aluminosilicate nanoclay mineral, have recently emerged as a possible nanomaterial for countless applications due to their specific chemical structure, tubular shape, high aspect ratio, biocompatibility and low toxicity. In this study, HNTs were incorporated into the epoxy resin matrix to improve its mechanical properties and thermal stability. However, heterogeneous size, surface charge and surface hydrogen bond formation, result in aggregation of HNTs in epoxies to a certain extent. Three specific techniques were used to integrate HNTs into neat epoxy resin (NE). The structure and morphology of the embedded nanotubes were confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Tensile testing was carried out and the fractured surface of the tested specimen was analysed using scanning electron microscopy (SEM). The thermal stability of the prepared nanocomposite materials was investigated by thermogravimetric (TG) and derivative thermogravimetry (DTG) studies. The obtained results indicated that improved properties of HNTs/epoxy nanocomposite materials were related to the unique properties of well-dispersed HNTs, agglomerate scale, and reduced void presence, and could be controlled by the manufacturing processes.",
publisher = "Springer International Publishing",
journal = "Experimental and Computational Investigations in Engineering",
booktitle = "Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials",
pages = "310-325",
doi = "10.1007/978-3-030-58362-0_18"
}

Jelić, A., Božić, A., Stamenović, M., Sekulić, M., Porobić, S., Dikić, S., Putić, S., Mitrović, N., Mladenović, G.,& Mitrović, A.. (2021). Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials. in Experimental and Computational Investigations in Engineering
Springer International Publishing., 310-325.
https://doi.org/10.1007/978-3-030-58362-0_18

Jelić A, Božić A, Stamenović M, Sekulić M, Porobić S, Dikić S, Putić S, Mitrović N, Mladenović G, Mitrović A. Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials. in Experimental and Computational Investigations in Engineering. 2021;:310-325.
doi:10.1007/978-3-030-58362-0_18 .

Jelić, Aleksandra, Božić, Aleksandra, Stamenović, Marina, Sekulić, Milica, Porobić, Slavica, Dikić, Stefan, Putić, Slaviša, Mitrović, Nenad, Mladenović, Goran, Mitrović, Aleksandra, "Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials" in Experimental and Computational Investigations in Engineering (2021):310-325,
https://doi.org/10.1007/978-3-030-58362-0_18 . .

TY  - JOUR
AU  - Nešić, Maja D.
AU  - Dučić, Tanja
AU  - Liang, Xinyue
AU  - Algarra, Manuel
AU  - Mi, Lan
AU  - Korićanac, Lela
AU  - Žakula, Jelena
AU  - Kop, Tatjana
AU  - Bjelaković, Mira
AU  - Mitrović, Aleksandra
AU  - Gojgić Cvijović, Gordana D.
AU  - Stepić, Milutin
AU  - Petković, Marijana
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9712
AB  - Objects of the present study are improved fullerene C60 drug carrier properties trough encapsulation by microbial polysaccharides, levan (LEV), pullulan (PUL), and their hydrophobized cholesterol-derivatives (CHL and CHP), that show better interaction with cancer cells. The zeta potential, polydispersity index, and the diameter of particles were determined, and their cytotoxicity against three cancer cell lines were tested. Biochemical changes in HeLa cells are analyzed by synchrotron radiation (SR) FTIR spectro-microscopy combined with the principal component analysis (PCA). The most significant changes occur in HeLa cells treated with LEV-C60 and correspond to the changes in the protein region, i.e. Amide I band, and the changes in the structure of lipid bodies and membrane fluidity are evident. The highest cytotoxicity was also induced by LEV-C60. In HeLa cells, cytotoxicity could not be strictly associated with biochemical changes in lipids, proteins and nucleic acids, but these findings are significant contribution to the study of the mechanism of interaction of C60-based nanoparticles with cellular biomolecules. In conclusion, LEV, PUL, CHL, and CHP enhanced fullerene C60 potential to be used as target drug delivery system with the ability to induce specific intracellular changes in HeLa cancer cells.
T2  - International Journal of Biological Macromolecules
T1  - SR-FTIR spectro-microscopic interaction study of biochemical changes in HeLa cells induced by Levan-C60, Pullulan-C60, and their cholesterol-derivatives
VL  - 165
SP  - 2541
EP  - 2549
DO  - 10.1016/j.ijbiomac.2020.10.141
ER  - 

@article{
author = "Nešić, Maja D. and Dučić, Tanja and Liang, Xinyue and Algarra, Manuel and Mi, Lan and Korićanac, Lela and Žakula, Jelena and Kop, Tatjana and Bjelaković, Mira and Mitrović, Aleksandra and Gojgić Cvijović, Gordana D. and Stepić, Milutin and Petković, Marijana",
year = "2020",
abstract = "Objects of the present study are improved fullerene C60 drug carrier properties trough encapsulation by microbial polysaccharides, levan (LEV), pullulan (PUL), and their hydrophobized cholesterol-derivatives (CHL and CHP), that show better interaction with cancer cells. The zeta potential, polydispersity index, and the diameter of particles were determined, and their cytotoxicity against three cancer cell lines were tested. Biochemical changes in HeLa cells are analyzed by synchrotron radiation (SR) FTIR spectro-microscopy combined with the principal component analysis (PCA). The most significant changes occur in HeLa cells treated with LEV-C60 and correspond to the changes in the protein region, i.e. Amide I band, and the changes in the structure of lipid bodies and membrane fluidity are evident. The highest cytotoxicity was also induced by LEV-C60. In HeLa cells, cytotoxicity could not be strictly associated with biochemical changes in lipids, proteins and nucleic acids, but these findings are significant contribution to the study of the mechanism of interaction of C60-based nanoparticles with cellular biomolecules. In conclusion, LEV, PUL, CHL, and CHP enhanced fullerene C60 potential to be used as target drug delivery system with the ability to induce specific intracellular changes in HeLa cancer cells.",
journal = "International Journal of Biological Macromolecules",
title = "SR-FTIR spectro-microscopic interaction study of biochemical changes in HeLa cells induced by Levan-C60, Pullulan-C60, and their cholesterol-derivatives",
volume = "165",
pages = "2541-2549",
doi = "10.1016/j.ijbiomac.2020.10.141"
}

Nešić, M. D., Dučić, T., Liang, X., Algarra, M., Mi, L., Korićanac, L., Žakula, J., Kop, T., Bjelaković, M., Mitrović, A., Gojgić Cvijović, G. D., Stepić, M.,& Petković, M.. (2020). SR-FTIR spectro-microscopic interaction study of biochemical changes in HeLa cells induced by Levan-C60, Pullulan-C60, and their cholesterol-derivatives. in International Journal of Biological Macromolecules, 165, 2541-2549.
https://doi.org/10.1016/j.ijbiomac.2020.10.141

Nešić MD, Dučić T, Liang X, Algarra M, Mi L, Korićanac L, Žakula J, Kop T, Bjelaković M, Mitrović A, Gojgić Cvijović GD, Stepić M, Petković M. SR-FTIR spectro-microscopic interaction study of biochemical changes in HeLa cells induced by Levan-C60, Pullulan-C60, and their cholesterol-derivatives. in International Journal of Biological Macromolecules. 2020;165:2541-2549.
doi:10.1016/j.ijbiomac.2020.10.141 .

Nešić, Maja D., Dučić, Tanja, Liang, Xinyue, Algarra, Manuel, Mi, Lan, Korićanac, Lela, Žakula, Jelena, Kop, Tatjana, Bjelaković, Mira, Mitrović, Aleksandra, Gojgić Cvijović, Gordana D., Stepić, Milutin, Petković, Marijana, "SR-FTIR spectro-microscopic interaction study of biochemical changes in HeLa cells induced by Levan-C60, Pullulan-C60, and their cholesterol-derivatives" in International Journal of Biological Macromolecules, 165 (2020):2541-2549,
https://doi.org/10.1016/j.ijbiomac.2020.10.141 . .

TY  - CHAP
AU  - Mitrović, Aleksandra
AU  - Stamenković, Dragomir
AU  - Popović, Dejana
AU  - Dragičević, Aleksandra
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8526
AB  - Hydrogels have peculiar physical and chemical properties and therefore, are used in a variety of biomedical applications including drug delivery agents, prosthetic devices, the repair and replacement of soft tissues, contact lenses, etc. Consequently, investigation of mechanical, physical and chemical properties is crucial in biomedical application of hydrogels. Poly (2-hydroxyethyl methacrylate) (pHEMA), as a biocompatible hydrogel, was first hydrogel used for making soft contact lenses. Many researches have been modified pHEMA with the aim of improving its properties. Application of nanotechnology is one of the possible solutions for improving the characteristics of this biocompatible hydrogel. In this paper, polyhydroxyethyl methacrylate was used as standard material for soft contact lenses (SL 38). This material was incorporated with fullerene C60 (SL38-A), fullerol C60(OH)24 (SL 38-B) and fullerene metformin hydroxylate C60(OH)12(OC4N5H10)12 (SL 38-C), respectively. Three new nanophotonic soft contact lenses were made. The main goal of this research was to develop appropriate process parameters for soft contact lens micro-turning. Also, studying the thermal decomposition of standard soft contact lens, pHEMA, as well as three new nanophotonic soft contact lenses was one of the main objectives. Results have shown that manufacturing process of nanofotonic soft contact lens is considered to be a micro-turning process regarding the cutting depth and tool nose ratio. Thermal stability of all three nanofotonic soft contact lenses was significantly improved comparing to the standard soft contact lens. Still, further research needs to be done so these nonophotonic soft contact lenses could find practical application in the field of biomedical engineering. © Springer Nature Switzerland AG 2020.
T2  - Lecture Notes in Networks and Systems
T1  - Manufacturing Process and Thermal Stability of Nanophotonic Soft Contact Lenses
VL  - 90
SP  - 184
EP  - 199
DO  - 10.1007/978-3-030-30853-7_11
ER  - 

@inbook{
author = "Mitrović, Aleksandra and Stamenković, Dragomir and Popović, Dejana and Dragičević, Aleksandra",
year = "2020",
abstract = "Hydrogels have peculiar physical and chemical properties and therefore, are used in a variety of biomedical applications including drug delivery agents, prosthetic devices, the repair and replacement of soft tissues, contact lenses, etc. Consequently, investigation of mechanical, physical and chemical properties is crucial in biomedical application of hydrogels. Poly (2-hydroxyethyl methacrylate) (pHEMA), as a biocompatible hydrogel, was first hydrogel used for making soft contact lenses. Many researches have been modified pHEMA with the aim of improving its properties. Application of nanotechnology is one of the possible solutions for improving the characteristics of this biocompatible hydrogel. In this paper, polyhydroxyethyl methacrylate was used as standard material for soft contact lenses (SL 38). This material was incorporated with fullerene C60 (SL38-A), fullerol C60(OH)24 (SL 38-B) and fullerene metformin hydroxylate C60(OH)12(OC4N5H10)12 (SL 38-C), respectively. Three new nanophotonic soft contact lenses were made. The main goal of this research was to develop appropriate process parameters for soft contact lens micro-turning. Also, studying the thermal decomposition of standard soft contact lens, pHEMA, as well as three new nanophotonic soft contact lenses was one of the main objectives. Results have shown that manufacturing process of nanofotonic soft contact lens is considered to be a micro-turning process regarding the cutting depth and tool nose ratio. Thermal stability of all three nanofotonic soft contact lenses was significantly improved comparing to the standard soft contact lens. Still, further research needs to be done so these nonophotonic soft contact lenses could find practical application in the field of biomedical engineering. © Springer Nature Switzerland AG 2020.",
journal = "Lecture Notes in Networks and Systems",
booktitle = "Manufacturing Process and Thermal Stability of Nanophotonic Soft Contact Lenses",
volume = "90",
pages = "184-199",
doi = "10.1007/978-3-030-30853-7_11"
}

Mitrović, A., Stamenković, D., Popović, D.,& Dragičević, A.. (2020). Manufacturing Process and Thermal Stability of Nanophotonic Soft Contact Lenses. in Lecture Notes in Networks and Systems, 90, 184-199.
https://doi.org/10.1007/978-3-030-30853-7_11

Mitrović A, Stamenković D, Popović D, Dragičević A. Manufacturing Process and Thermal Stability of Nanophotonic Soft Contact Lenses. in Lecture Notes in Networks and Systems. 2020;90:184-199.
doi:10.1007/978-3-030-30853-7_11 .

Mitrović, Aleksandra, Stamenković, Dragomir, Popović, Dejana, Dragičević, Aleksandra, "Manufacturing Process and Thermal Stability of Nanophotonic Soft Contact Lenses" in Lecture Notes in Networks and Systems, 90 (2020):184-199,
https://doi.org/10.1007/978-3-030-30853-7_11 . .

TY  - CHAP
AU  - Mitrović, Aleksandra
AU  - Mitrović, Nenad
AU  - Maslarević, Aleksandar
AU  - Adžić, Vuk
AU  - Popović, Dejana
AU  - Milošević, Miloš
AU  - Antonović, Dušan
PY  - 2019
UR  - http://link.springer.com/10.1007/978-3-319-99620-2_1
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8106
AB  - One of the main objectives in research and development of resin based cements (RBCs) is to enhance their clinical longevity and ease of use. In spite of the undeniable technological advances introduced in the last few decades, the polymerization shrinkage i.e. strain that accompanies the chain-growth polymerization of dimethacrylate monomers remains one of the major concerns for the clinical performance of composite restorations. Also, RBCs can produce a considerable amount of heat, due to the light energy from the curing lights and exothermic reaction of polymerization. The purpose of this study was to determine the temperature changes during the photo-polymerization using thermocouples and to measure strain field of the self-etching, self-adhesive RBC, Maxcem Elite (Kerr, Orange, CA, USA) (ø5 × 1Â mm - Group I and ø5 × 2Â mm - Group II) using experimental technique, 3D Digital Image Correlation (DIC) method. Digital images were recorded immediately after photo-polymerization of the samples with a LED-curing unit for 20Â s, according to manufacturer’s recommendation. Vickers microhardness was determined after photo-polymerization and after 24Â h. Temperature curves for both groups indicated similar patterns but the peak temperature of Group II was significantly higher compared to peak temperature of Group I. DIC showed that peripheral zone of the samples had the highest strain values in both groups. Group I indicated significantly higher values of hardness. All the results were material-dependent and probably correlated to the composition of each material, which is not fully disclosed by the manufacturers. © Springer Nature Switzerland AG 2019.
T2  - Lecture Notes in Networks and Systems
T1  - Thermal and Mechanical Characteristics of Dual Cure Self-etching, Self-adhesive Resin Based Cement
VL  - 54
SP  - 3
EP  - 15
DO  - 10.1007/978-3-319-99620-2_1
ER  - 

@inbook{
author = "Mitrović, Aleksandra and Mitrović, Nenad and Maslarević, Aleksandar and Adžić, Vuk and Popović, Dejana and Milošević, Miloš and Antonović, Dušan",
year = "2019",
abstract = "One of the main objectives in research and development of resin based cements (RBCs) is to enhance their clinical longevity and ease of use. In spite of the undeniable technological advances introduced in the last few decades, the polymerization shrinkage i.e. strain that accompanies the chain-growth polymerization of dimethacrylate monomers remains one of the major concerns for the clinical performance of composite restorations. Also, RBCs can produce a considerable amount of heat, due to the light energy from the curing lights and exothermic reaction of polymerization. The purpose of this study was to determine the temperature changes during the photo-polymerization using thermocouples and to measure strain field of the self-etching, self-adhesive RBC, Maxcem Elite (Kerr, Orange, CA, USA) (ø5 × 1Â mm - Group I and ø5 × 2Â mm - Group II) using experimental technique, 3D Digital Image Correlation (DIC) method. Digital images were recorded immediately after photo-polymerization of the samples with a LED-curing unit for 20Â s, according to manufacturer’s recommendation. Vickers microhardness was determined after photo-polymerization and after 24Â h. Temperature curves for both groups indicated similar patterns but the peak temperature of Group II was significantly higher compared to peak temperature of Group I. DIC showed that peripheral zone of the samples had the highest strain values in both groups. Group I indicated significantly higher values of hardness. All the results were material-dependent and probably correlated to the composition of each material, which is not fully disclosed by the manufacturers. © Springer Nature Switzerland AG 2019.",
journal = "Lecture Notes in Networks and Systems",
booktitle = "Thermal and Mechanical Characteristics of Dual Cure Self-etching, Self-adhesive Resin Based Cement",
volume = "54",
pages = "3-15",
doi = "10.1007/978-3-319-99620-2_1"
}

Mitrović, A., Mitrović, N., Maslarević, A., Adžić, V., Popović, D., Milošević, M.,& Antonović, D.. (2019). Thermal and Mechanical Characteristics of Dual Cure Self-etching, Self-adhesive Resin Based Cement. in Lecture Notes in Networks and Systems, 54, 3-15.
https://doi.org/10.1007/978-3-319-99620-2_1

Mitrović A, Mitrović N, Maslarević A, Adžić V, Popović D, Milošević M, Antonović D. Thermal and Mechanical Characteristics of Dual Cure Self-etching, Self-adhesive Resin Based Cement. in Lecture Notes in Networks and Systems. 2019;54:3-15.
doi:10.1007/978-3-319-99620-2_1 .

Mitrović, Aleksandra, Mitrović, Nenad, Maslarević, Aleksandar, Adžić, Vuk, Popović, Dejana, Milošević, Miloš, Antonović, Dušan, "Thermal and Mechanical Characteristics of Dual Cure Self-etching, Self-adhesive Resin Based Cement" in Lecture Notes in Networks and Systems, 54 (2019):3-15,
https://doi.org/10.1007/978-3-319-99620-2_1 . .

TY  - JOUR
AU  - Mitrović, Aleksandra
AU  - Antonović, Dušan
AU  - Tanasić, Ivan
AU  - Mitrović, Nenad
AU  - Bakić, Gordana M.
AU  - Popović, Dejana
AU  - Milošević, Miloš
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8670
AB  - The introduction of resin-based cements and an adhesive-bonding system in daily dental practice has given the opportunity to increase the retention of previously conventional cemented restorations and the optimal results in esthetic. This experimental study employed the 3D Digital Image Correlation Method (3D-DIC) for detecting shrinkage strain in four dual cured composite cements. The aim was to visualize measure, analyze, and compare strain fields in four resin-based cements using the 3D-DIC method. A total of 72 samples were divided into 4 groups considering variations in sample types, diameter, and thickness. Four types of composite cements: RelyX U200 (3 M ESPE, St. Paul, MN, USA), MaxCem Elite (Kerr, Orange, CA, USA), Multilink Automix (Ivoclar Vivadent, Schaan, Liechtenstein), and SeT PP (SDI, Australia) were used. Each type had diameters of 3 mm, 4 mm, and 5 mm, respectively, combined with two different values of thickness: 1 mm and 2 mm. Thickness had an important role on strain detected in all tested materials showing higher strain in samples with 2 mm thickness compared to 1 mm samples. Shrinkage strain values were the highest in Set PP samples indicated the possibility of undesirable de-bonding.
T2  - BioMed Research International
T1  - 3D Digital Image Correlation Analysis of the Shrinkage Strain in Four Dual Cure Composite Cements
VL  - 2019
SP  - 2041348
DO  - 10.1155/2019/2041348
ER  - 

@article{
author = "Mitrović, Aleksandra and Antonović, Dušan and Tanasić, Ivan and Mitrović, Nenad and Bakić, Gordana M. and Popović, Dejana and Milošević, Miloš",
year = "2019",
abstract = "The introduction of resin-based cements and an adhesive-bonding system in daily dental practice has given the opportunity to increase the retention of previously conventional cemented restorations and the optimal results in esthetic. This experimental study employed the 3D Digital Image Correlation Method (3D-DIC) for detecting shrinkage strain in four dual cured composite cements. The aim was to visualize measure, analyze, and compare strain fields in four resin-based cements using the 3D-DIC method. A total of 72 samples were divided into 4 groups considering variations in sample types, diameter, and thickness. Four types of composite cements: RelyX U200 (3 M ESPE, St. Paul, MN, USA), MaxCem Elite (Kerr, Orange, CA, USA), Multilink Automix (Ivoclar Vivadent, Schaan, Liechtenstein), and SeT PP (SDI, Australia) were used. Each type had diameters of 3 mm, 4 mm, and 5 mm, respectively, combined with two different values of thickness: 1 mm and 2 mm. Thickness had an important role on strain detected in all tested materials showing higher strain in samples with 2 mm thickness compared to 1 mm samples. Shrinkage strain values were the highest in Set PP samples indicated the possibility of undesirable de-bonding.",
journal = "BioMed Research International",
title = "3D Digital Image Correlation Analysis of the Shrinkage Strain in Four Dual Cure Composite Cements",
volume = "2019",
pages = "2041348",
doi = "10.1155/2019/2041348"
}

Mitrović, A., Antonović, D., Tanasić, I., Mitrović, N., Bakić, G. M., Popović, D.,& Milošević, M.. (2019). 3D Digital Image Correlation Analysis of the Shrinkage Strain in Four Dual Cure Composite Cements. in BioMed Research International, 2019, 2041348.
https://doi.org/10.1155/2019/2041348

Mitrović A, Antonović D, Tanasić I, Mitrović N, Bakić GM, Popović D, Milošević M. 3D Digital Image Correlation Analysis of the Shrinkage Strain in Four Dual Cure Composite Cements. in BioMed Research International. 2019;2019:2041348.
doi:10.1155/2019/2041348 .

Mitrović, Aleksandra, Antonović, Dušan, Tanasić, Ivan, Mitrović, Nenad, Bakić, Gordana M., Popović, Dejana, Milošević, Miloš, "3D Digital Image Correlation Analysis of the Shrinkage Strain in Four Dual Cure Composite Cements" in BioMed Research International, 2019 (2019):2041348,
https://doi.org/10.1155/2019/2041348 . .