TY  - JOUR
AU  - Gligorijević, Bojan R.
AU  - Vilotijević, Miroljub N.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11580
AB  - The current study focuses on creating an initial highly alkaline simulated body fluid whose pH can be decreased to a physiological range by adding CO2 (protein-free simulated body fluid) or a combination of CO2 and human proteins (protein-containing simulated body fluid). The effects of dissolved human proteins, Ca2+ ions, and immersed plasma-sprayed hydroxyapatite coatings on the pH and chemical instability of prepared simulated body fluids were investigated. The physiological concentration of dissolved human proteins decreased the pH instability in prepared simulated body fluids by 60% and the physiological concentration of dissolved Ca2+ ions by 15%. The effect of immersing the hydroxyapatite coatings was negligible. In terms of chemical instability, the dissolution of Ca2+ ions caused the blurring of protein-free simulated body fluids after 0.6-1.0 h. In protein-containing simulated body fluids, this phenomenon was undetectable due to their opacity. The effects of human protein presence on the carbonated-apatite-forming ability on the surfaces of immersed hydroxyapatite coatings in the prepared simulated body fluids were also assessed. The experiments validated the bioactivity of plasma-sprayed hydroxyapatite coatings in the prepared simulated body fluids, regardless of protein presence. On the other hand, under the different experimental conditions (unregulated or regulated pH), the human protein presence had an inhibitory (unregulated pH) or indifferent/promoting (regulated pH) influence on the carbonated-apatite-forming ability. The results of the present study are discussed, as well as the strengths and shortcomings of the prepared simulated body fluids, and are compared to those of previous relevant investigations.
T2  - Iranian Journal of Chemistry and Chemical Engineering
T1  - Simulated Body Fluids Prepared with Natural Buffers and System for Active pH Regulation
VL  - 41
IS  - 9
SP  - 2918
EP  - 2935
DO  - 10.30492/ijcce.2021.530070.4823
ER  - 

@article{
author = "Gligorijević, Bojan R. and Vilotijević, Miroljub N.",
year = "2022",
abstract = "The current study focuses on creating an initial highly alkaline simulated body fluid whose pH can be decreased to a physiological range by adding CO2 (protein-free simulated body fluid) or a combination of CO2 and human proteins (protein-containing simulated body fluid). The effects of dissolved human proteins, Ca2+ ions, and immersed plasma-sprayed hydroxyapatite coatings on the pH and chemical instability of prepared simulated body fluids were investigated. The physiological concentration of dissolved human proteins decreased the pH instability in prepared simulated body fluids by 60% and the physiological concentration of dissolved Ca2+ ions by 15%. The effect of immersing the hydroxyapatite coatings was negligible. In terms of chemical instability, the dissolution of Ca2+ ions caused the blurring of protein-free simulated body fluids after 0.6-1.0 h. In protein-containing simulated body fluids, this phenomenon was undetectable due to their opacity. The effects of human protein presence on the carbonated-apatite-forming ability on the surfaces of immersed hydroxyapatite coatings in the prepared simulated body fluids were also assessed. The experiments validated the bioactivity of plasma-sprayed hydroxyapatite coatings in the prepared simulated body fluids, regardless of protein presence. On the other hand, under the different experimental conditions (unregulated or regulated pH), the human protein presence had an inhibitory (unregulated pH) or indifferent/promoting (regulated pH) influence on the carbonated-apatite-forming ability. The results of the present study are discussed, as well as the strengths and shortcomings of the prepared simulated body fluids, and are compared to those of previous relevant investigations.",
journal = "Iranian Journal of Chemistry and Chemical Engineering",
title = "Simulated Body Fluids Prepared with Natural Buffers and System for Active pH Regulation",
volume = "41",
number = "9",
pages = "2918-2935",
doi = "10.30492/ijcce.2021.530070.4823"
}

Gligorijević, B. R.,& Vilotijević, M. N.. (2022). Simulated Body Fluids Prepared with Natural Buffers and System for Active pH Regulation. in Iranian Journal of Chemistry and Chemical Engineering, 41(9), 2918-2935.
https://doi.org/10.30492/ijcce.2021.530070.4823

Gligorijević BR, Vilotijević MN. Simulated Body Fluids Prepared with Natural Buffers and System for Active pH Regulation. in Iranian Journal of Chemistry and Chemical Engineering. 2022;41(9):2918-2935.
doi:10.30492/ijcce.2021.530070.4823 .

Gligorijević, Bojan R., Vilotijević, Miroljub N., "Simulated Body Fluids Prepared with Natural Buffers and System for Active pH Regulation" in Iranian Journal of Chemistry and Chemical Engineering, 41, no. 9 (2022):2918-2935,
https://doi.org/10.30492/ijcce.2021.530070.4823 . .

TY  - JOUR
AU  - Gligorijević, Bojan R.
AU  - Vilotijević, Miroljub N.
AU  - Šćepanović, Maja J.
AU  - Radovanovic, Radovan V.
AU  - Radović, Nenad A.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1669
AB  - The present study estimated the cracking phenomenon in as-plasma-sprayed hydroxylapatite coatings (HACs) after they were being subjected to the severe cutting conditions in the direction perpendicular to the coating/substrate interface. In order to evaluate the effects of substrate preheating on the occurrence of micro-cracks, the HACs were deposited at different initial substrate temperatures (T-S = 20, 100 and 200 degrees C). The changes in phase composition and HA splat morphology with T-S were observed and were correlated with the cracking occurrence. The results showed that severe cutting conditions introduced a localized cracking in the regions of HACs dominantly attributed to the brittle hydroxyl- deficient amorphous calcium phosphate (ACP) phase. This effect was particularly observable in the HACs deposited without preheating of substrate. On the other hand, the preheating of substrate reduced the presence of micro-cracks and caused insignificant changes in the average local phase composition. In HACs deposited with preheating of substrate, the HA splats (of which HACs are composed) were thinner and recrystallized HA regions seemed smaller in size and more evenly distributed. These results implied potentially important roles of the HA splat formation mechanism on the distribution of ACP and recrystallized HA regions in the as-plasma-sprayed HACs and the cracking resistance of HACs.
T2  - Hemijska industrija
T1  - Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures
VL  - 71
IS  - 3
SP  - 241
EP  - 249
DO  - 10.2298/HEMIND160513034G
ER  - 

@article{
author = "Gligorijević, Bojan R. and Vilotijević, Miroljub N. and Šćepanović, Maja J. and Radovanovic, Radovan V. and Radović, Nenad A.",
year = "2017",
abstract = "The present study estimated the cracking phenomenon in as-plasma-sprayed hydroxylapatite coatings (HACs) after they were being subjected to the severe cutting conditions in the direction perpendicular to the coating/substrate interface. In order to evaluate the effects of substrate preheating on the occurrence of micro-cracks, the HACs were deposited at different initial substrate temperatures (T-S = 20, 100 and 200 degrees C). The changes in phase composition and HA splat morphology with T-S were observed and were correlated with the cracking occurrence. The results showed that severe cutting conditions introduced a localized cracking in the regions of HACs dominantly attributed to the brittle hydroxyl- deficient amorphous calcium phosphate (ACP) phase. This effect was particularly observable in the HACs deposited without preheating of substrate. On the other hand, the preheating of substrate reduced the presence of micro-cracks and caused insignificant changes in the average local phase composition. In HACs deposited with preheating of substrate, the HA splats (of which HACs are composed) were thinner and recrystallized HA regions seemed smaller in size and more evenly distributed. These results implied potentially important roles of the HA splat formation mechanism on the distribution of ACP and recrystallized HA regions in the as-plasma-sprayed HACs and the cracking resistance of HACs.",
journal = "Hemijska industrija",
title = "Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures",
volume = "71",
number = "3",
pages = "241-249",
doi = "10.2298/HEMIND160513034G"
}

Gligorijević, B. R., Vilotijević, M. N., Šćepanović, M. J., Radovanovic, R. V.,& Radović, N. A.. (2017). Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures. in Hemijska industrija, 71(3), 241-249.
https://doi.org/10.2298/HEMIND160513034G

Gligorijević BR, Vilotijević MN, Šćepanović MJ, Radovanovic RV, Radović NA. Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures. in Hemijska industrija. 2017;71(3):241-249.
doi:10.2298/HEMIND160513034G .

Gligorijević, Bojan R., Vilotijević, Miroljub N., Šćepanović, Maja J., Radovanovic, Radovan V., Radović, Nenad A., "Cracking caused by cutting of plasma-sprayed hydroxyapatite coatings and its relation to the structural features of coatings deposited at different initial substrate temperatures" in Hemijska industrija, 71, no. 3 (2017):241-249,
https://doi.org/10.2298/HEMIND160513034G . .

TY  - JOUR
AU  - Gligorijević, Bojan R.
AU  - Vilotijević, Miroljub N.
AU  - Šćepanović, Maja
AU  - Vuković, Nikola S.
AU  - Radović, Nenad A.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/825
AB  - The aim of the present study was to investigate the influence of substrate preheating on the structural properties of hydroxyapatite coatings (HACs) deposited by using the high power (52 kW) laminar plasma jet. The deposition experiments were performed within the 20-200 degrees C temperature range at different stand-off distances. The structural properties in the thickness direction and at the surface of the HACs were investigated by using the micro-Raman spectroscopy, scanning electron microscopy coupled with energy dispersive spectrometry, and X-ray powder diffractometry. The deposition without the preheating of the substrate produced HACs with crystallinity gradient in the thickness direction. At the stand-off distance of 80 mm, the preheating of the substrate at 200 degrees C practically eliminated the crystallinity gradient. At distances from the coating/substrate interface shorter than similar to 100 mu m, the increase of crystallinity with the preheating of the substrate was dominantly attributed to the recrystallization of hydroxyl-rich ACP into HA. At longer distances and higher initial substrate temperatures ( GT 100 degrees C), the crystallinity changes were negligible, whereas the recrystallization of hydroxyl-deficient ACP into oxyapatite (OA) was also possible. The X-ray diffractometry indicated the deposition conditions under which a minimum residual stress was achieved. The results of the present study strongly suggested the relation between the ACP - GT HA remystallization process and the bonding strength of the HACs. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
PB  - Elsevier
T2  - Ceramics International
T1  - Substrate preheating and structural properties of power plasma sprayed hydroxyapatite coatings
VL  - 42
IS  - 1
SP  - 411
EP  - 420
DO  - 10.1016/j.ceramint.2015.08.125
ER  - 

@article{
author = "Gligorijević, Bojan R. and Vilotijević, Miroljub N. and Šćepanović, Maja and Vuković, Nikola S. and Radović, Nenad A.",
year = "2016",
abstract = "The aim of the present study was to investigate the influence of substrate preheating on the structural properties of hydroxyapatite coatings (HACs) deposited by using the high power (52 kW) laminar plasma jet. The deposition experiments were performed within the 20-200 degrees C temperature range at different stand-off distances. The structural properties in the thickness direction and at the surface of the HACs were investigated by using the micro-Raman spectroscopy, scanning electron microscopy coupled with energy dispersive spectrometry, and X-ray powder diffractometry. The deposition without the preheating of the substrate produced HACs with crystallinity gradient in the thickness direction. At the stand-off distance of 80 mm, the preheating of the substrate at 200 degrees C practically eliminated the crystallinity gradient. At distances from the coating/substrate interface shorter than similar to 100 mu m, the increase of crystallinity with the preheating of the substrate was dominantly attributed to the recrystallization of hydroxyl-rich ACP into HA. At longer distances and higher initial substrate temperatures ( GT 100 degrees C), the crystallinity changes were negligible, whereas the recrystallization of hydroxyl-deficient ACP into oxyapatite (OA) was also possible. The X-ray diffractometry indicated the deposition conditions under which a minimum residual stress was achieved. The results of the present study strongly suggested the relation between the ACP - GT HA remystallization process and the bonding strength of the HACs. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Substrate preheating and structural properties of power plasma sprayed hydroxyapatite coatings",
volume = "42",
number = "1",
pages = "411-420",
doi = "10.1016/j.ceramint.2015.08.125"
}

Gligorijević, B. R., Vilotijević, M. N., Šćepanović, M., Vuković, N. S.,& Radović, N. A.. (2016). Substrate preheating and structural properties of power plasma sprayed hydroxyapatite coatings. in Ceramics International
Elsevier., 42(1), 411-420.
https://doi.org/10.1016/j.ceramint.2015.08.125

Gligorijević BR, Vilotijević MN, Šćepanović M, Vuković NS, Radović NA. Substrate preheating and structural properties of power plasma sprayed hydroxyapatite coatings. in Ceramics International. 2016;42(1):411-420.
doi:10.1016/j.ceramint.2015.08.125 .

Gligorijević, Bojan R., Vilotijević, Miroljub N., Šćepanović, Maja, Vuković, Nikola S., Radović, Nenad A., "Substrate preheating and structural properties of power plasma sprayed hydroxyapatite coatings" in Ceramics International, 42, no. 1 (2016):411-420,
https://doi.org/10.1016/j.ceramint.2015.08.125 . .

TY  - JOUR
AU  - Gligorijević, Bojan R.
AU  - Vilotijević, Miroljub N.
AU  - Šćepanović, Maja
AU  - Vidovic, Dragoslav
AU  - Radović, Nenad A.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1245
AB  - The aim of this work was to examine the dependence of the local surface structure (surface structural heterogeneity) on the local thickness (thickness uniformity) and structure properties along the thickness of hydroxyapatite coatings (HACs) deposited by using the high power (52 kW) laminar plasma jet. For the deposition process, a relatively small size of the feedstock hydroxyapatite powder (HAP) (33 mu m) was used. The HACs were deposited at different stand-off distances (SODs) (80, 100, and 150 mm) without preheating of substrates. The thickness measurements were performed by using the calibrated micrometer and light microscopy (LM). The surface micro-structure was analyzed by using the micro-Raman spectroscopy (MRS), whereas the micro-structure along the thickness of HACs was studied by using the MRS, X-ray powder diffractometry (XRPD), and LM (combined with chemical etching). The results showed a heterogeneous phase distribution on the surface of each HAC analyzed as well as the non-uniform thickness of HACs. Apparently, a correlation existed between the local surface structure and the local thickness of HACs. However, the MRS, XRPD, and LM analyses of micro-structure along the thickness of HACs indicated that the differences in the local surface structure could be related to the different recrystallization established during the plasma deposition process in the different parts along the thickness of each HAC analyzed. (C) 2016 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Surface structural heterogeneity of high power plasma-sprayed hydroxyapatite coatings
VL  - 687
SP  - 421
EP  - 430
DO  - 10.1016/j.jallcom.2016.06.163
ER  - 

@article{
author = "Gligorijević, Bojan R. and Vilotijević, Miroljub N. and Šćepanović, Maja and Vidovic, Dragoslav and Radović, Nenad A.",
year = "2016",
abstract = "The aim of this work was to examine the dependence of the local surface structure (surface structural heterogeneity) on the local thickness (thickness uniformity) and structure properties along the thickness of hydroxyapatite coatings (HACs) deposited by using the high power (52 kW) laminar plasma jet. For the deposition process, a relatively small size of the feedstock hydroxyapatite powder (HAP) (33 mu m) was used. The HACs were deposited at different stand-off distances (SODs) (80, 100, and 150 mm) without preheating of substrates. The thickness measurements were performed by using the calibrated micrometer and light microscopy (LM). The surface micro-structure was analyzed by using the micro-Raman spectroscopy (MRS), whereas the micro-structure along the thickness of HACs was studied by using the MRS, X-ray powder diffractometry (XRPD), and LM (combined with chemical etching). The results showed a heterogeneous phase distribution on the surface of each HAC analyzed as well as the non-uniform thickness of HACs. Apparently, a correlation existed between the local surface structure and the local thickness of HACs. However, the MRS, XRPD, and LM analyses of micro-structure along the thickness of HACs indicated that the differences in the local surface structure could be related to the different recrystallization established during the plasma deposition process in the different parts along the thickness of each HAC analyzed. (C) 2016 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Surface structural heterogeneity of high power plasma-sprayed hydroxyapatite coatings",
volume = "687",
pages = "421-430",
doi = "10.1016/j.jallcom.2016.06.163"
}

Gligorijević, B. R., Vilotijević, M. N., Šćepanović, M., Vidovic, D.,& Radović, N. A.. (2016). Surface structural heterogeneity of high power plasma-sprayed hydroxyapatite coatings. in Journal of Alloys and Compounds, 687, 421-430.
https://doi.org/10.1016/j.jallcom.2016.06.163

Gligorijević BR, Vilotijević MN, Šćepanović M, Vidovic D, Radović NA. Surface structural heterogeneity of high power plasma-sprayed hydroxyapatite coatings. in Journal of Alloys and Compounds. 2016;687:421-430.
doi:10.1016/j.jallcom.2016.06.163 .

Gligorijević, Bojan R., Vilotijević, Miroljub N., Šćepanović, Maja, Vidovic, Dragoslav, Radović, Nenad A., "Surface structural heterogeneity of high power plasma-sprayed hydroxyapatite coatings" in Journal of Alloys and Compounds, 687 (2016):421-430,
https://doi.org/10.1016/j.jallcom.2016.06.163 . .