TY  - JOUR
AU  - Jovanović, J
AU  - Adnađević, Borivoj
AU  - Suljovrujić, Edin H.
AU  - Ignjatović, Nenad L.
AU  - Uskoković, Dragan
PY  - 2003
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6357
AB  - Injectable and gas-permeable composite cements, polydimethylsiloxane/hydroxyapatite (PDMS/HAp), were synthesized using bi-component polysiloxane precursors (RTV-A and RTV-B), which react by hydrosilylation, and different mass fractions of hydroxyapatite (HAp) having particle size of about 100 nm. The effect of HAp mass fraction (0-60%) on the thermodynamic and kinetic parameters of polysiloxanes cross-linking, i.e., PDMS/HAp composite preparation, was investigated by means of differential scanning calorimetry (DSC). It was determined that small mass fractions of HAp (up to about 10%) cause a decrease in temperature (T-max), and activation energy (E-a) of the investigated cross-linking process, while the total heat of the process (H-tot) increases. For the HAp mass fraction greater than 20%, an opposite effect was observed. The temperature and the time interval of cross-linking increase rapidly for smaller, but slowly, almost insignificantly, for larger HAp mass fractions. The determined order (n) of the reaction shows a trend similar to H-tot, but due to small variations found, this does not merit discussion.
T2  - Materials Science Forum
T1  - Influence of the HAp ratio on the thermodynamic and kinetic parameters of PDMS/HAp composites cross-linking
VL  - 413
SP  - 263
EP  - 268
UR  - https://hdl.handle.net/21.15107/rcub_vinar_6357
ER  - 

@article{
author = "Jovanović, J and Adnađević, Borivoj and Suljovrujić, Edin H. and Ignjatović, Nenad L. and Uskoković, Dragan",
year = "2003",
abstract = "Injectable and gas-permeable composite cements, polydimethylsiloxane/hydroxyapatite (PDMS/HAp), were synthesized using bi-component polysiloxane precursors (RTV-A and RTV-B), which react by hydrosilylation, and different mass fractions of hydroxyapatite (HAp) having particle size of about 100 nm. The effect of HAp mass fraction (0-60%) on the thermodynamic and kinetic parameters of polysiloxanes cross-linking, i.e., PDMS/HAp composite preparation, was investigated by means of differential scanning calorimetry (DSC). It was determined that small mass fractions of HAp (up to about 10%) cause a decrease in temperature (T-max), and activation energy (E-a) of the investigated cross-linking process, while the total heat of the process (H-tot) increases. For the HAp mass fraction greater than 20%, an opposite effect was observed. The temperature and the time interval of cross-linking increase rapidly for smaller, but slowly, almost insignificantly, for larger HAp mass fractions. The determined order (n) of the reaction shows a trend similar to H-tot, but due to small variations found, this does not merit discussion.",
journal = "Materials Science Forum",
title = "Influence of the HAp ratio on the thermodynamic and kinetic parameters of PDMS/HAp composites cross-linking",
volume = "413",
pages = "263-268",
url = "https://hdl.handle.net/21.15107/rcub_vinar_6357"
}

Jovanović, J., Adnađević, B., Suljovrujić, E. H., Ignjatović, N. L.,& Uskoković, D.. (2003). Influence of the HAp ratio on the thermodynamic and kinetic parameters of PDMS/HAp composites cross-linking. in Materials Science Forum, 413, 263-268.
https://hdl.handle.net/21.15107/rcub_vinar_6357

Jovanović J, Adnađević B, Suljovrujić EH, Ignjatović NL, Uskoković D. Influence of the HAp ratio on the thermodynamic and kinetic parameters of PDMS/HAp composites cross-linking. in Materials Science Forum. 2003;413:263-268.
https://hdl.handle.net/21.15107/rcub_vinar_6357 .

Jovanović, J, Adnađević, Borivoj, Suljovrujić, Edin H., Ignjatović, Nenad L., Uskoković, Dragan, "Influence of the HAp ratio on the thermodynamic and kinetic parameters of PDMS/HAp composites cross-linking" in Materials Science Forum, 413 (2003):263-268,
https://hdl.handle.net/21.15107/rcub_vinar_6357 .

TY  - JOUR
AU  - Ignjatović, Nenad L.
AU  - Jovanović, J.
AU  - Suljovrujić, Edin H.
AU  - Uskoković, Dragan
PY  - 2003
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2686
AB  - An injectable polydimethylsiloxane/hydroxyapatite (PDMS/HAp) composite cement was synthesised using linear PDMS and HAp (particles of about 100 nm in size) of different mass fractions. The effect of HAp mass fraction (5-60 mass%) on the hardness of PDMS/HAp composite cement was investigated. The hardness achieved is 25-49degreesShA. Differential scanning calorimetry (DSC) was used to study the cross-linking process and the influence of HAp on the temperature and duration of PDMS/HAp cross-linking. The microstructure of composite cement surfaces after 10 days in vivo tests was observed by scanning electron microscopy (SEM). The presence of well-adhered macrophages, fibroblasts and monocytes was found on the implant surface upon its extraction from the organism.
T2  - Bio-Medical Materials and Engineering
T1  - Injectable polydimethylsiloxane-hydroxyapatite composite cement
VL  - 13
IS  - 4
SP  - 401
EP  - 410
UR  - https://hdl.handle.net/21.15107/rcub_vinar_2686
ER  - 

@article{
author = "Ignjatović, Nenad L. and Jovanović, J. and Suljovrujić, Edin H. and Uskoković, Dragan",
year = "2003",
abstract = "An injectable polydimethylsiloxane/hydroxyapatite (PDMS/HAp) composite cement was synthesised using linear PDMS and HAp (particles of about 100 nm in size) of different mass fractions. The effect of HAp mass fraction (5-60 mass%) on the hardness of PDMS/HAp composite cement was investigated. The hardness achieved is 25-49degreesShA. Differential scanning calorimetry (DSC) was used to study the cross-linking process and the influence of HAp on the temperature and duration of PDMS/HAp cross-linking. The microstructure of composite cement surfaces after 10 days in vivo tests was observed by scanning electron microscopy (SEM). The presence of well-adhered macrophages, fibroblasts and monocytes was found on the implant surface upon its extraction from the organism.",
journal = "Bio-Medical Materials and Engineering",
title = "Injectable polydimethylsiloxane-hydroxyapatite composite cement",
volume = "13",
number = "4",
pages = "401-410",
url = "https://hdl.handle.net/21.15107/rcub_vinar_2686"
}

Ignjatović, N. L., Jovanović, J., Suljovrujić, E. H.,& Uskoković, D.. (2003). Injectable polydimethylsiloxane-hydroxyapatite composite cement. in Bio-Medical Materials and Engineering, 13(4), 401-410.
https://hdl.handle.net/21.15107/rcub_vinar_2686

Ignjatović NL, Jovanović J, Suljovrujić EH, Uskoković D. Injectable polydimethylsiloxane-hydroxyapatite composite cement. in Bio-Medical Materials and Engineering. 2003;13(4):401-410.
https://hdl.handle.net/21.15107/rcub_vinar_2686 .

Ignjatović, Nenad L., Jovanović, J., Suljovrujić, Edin H., Uskoković, Dragan, "Injectable polydimethylsiloxane-hydroxyapatite composite cement" in Bio-Medical Materials and Engineering, 13, no. 4 (2003):401-410,
https://hdl.handle.net/21.15107/rcub_vinar_2686 .

TY  - JOUR
AU  - Dumanović, Dragica
AU  - Juranić, Ivan O.
AU  - Dželetović, D.
AU  - Vasić, Vesna M.
AU  - Jovanović, J.
PY  - 1997
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2080
AB  - The prototropic exchange equilibria of two drugs, nizatidine (I) and ranitidine (II); and also of structurally related the N,N-dimethyl-2-nitro-1,1-ethenediamine molecule (III) were investigated. From the changes in electronic spectra in media of various acidity several protonation constants were determined. For nizatidine pK values were -0.82, 1.95, and 6.67; for ranitidine pK values were 1.95 and 8.13; and for III was 2.60. The hydroxylation equilibrium constant in strongly alkaline media was determined too. Corresponding pK(a) values were 13.23 for I, 13.26 for II and 13.76 for III. Molecular orbital calculations of electronic spectra confirmed that pK 1.95 for I and II, and pK 2.60 for III, are associated with C-protonation of nitroethenediamine fragment, while all pK(a) values correspond to the addition of HO- anion at the same double bond. (C) 1997 Elsevier Science B.V.
T2  - Journal of Pharmaceutical and Biomedical Analysis
T1  - Protolytic constants of nizatidine, ranitidine and N,N-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation
VL  - 15
IS  - 11
SP  - 1667
EP  - 1678
DO  - 10.1016/S0731-7085(96)01977-2
ER  - 

@article{
author = "Dumanović, Dragica and Juranić, Ivan O. and Dželetović, D. and Vasić, Vesna M. and Jovanović, J.",
year = "1997",
abstract = "The prototropic exchange equilibria of two drugs, nizatidine (I) and ranitidine (II); and also of structurally related the N,N-dimethyl-2-nitro-1,1-ethenediamine molecule (III) were investigated. From the changes in electronic spectra in media of various acidity several protonation constants were determined. For nizatidine pK values were -0.82, 1.95, and 6.67; for ranitidine pK values were 1.95 and 8.13; and for III was 2.60. The hydroxylation equilibrium constant in strongly alkaline media was determined too. Corresponding pK(a) values were 13.23 for I, 13.26 for II and 13.76 for III. Molecular orbital calculations of electronic spectra confirmed that pK 1.95 for I and II, and pK 2.60 for III, are associated with C-protonation of nitroethenediamine fragment, while all pK(a) values correspond to the addition of HO- anion at the same double bond. (C) 1997 Elsevier Science B.V.",
journal = "Journal of Pharmaceutical and Biomedical Analysis",
title = "Protolytic constants of nizatidine, ranitidine and N,N-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation",
volume = "15",
number = "11",
pages = "1667-1678",
doi = "10.1016/S0731-7085(96)01977-2"
}

Dumanović, D., Juranić, I. O., Dželetović, D., Vasić, V. M.,& Jovanović, J.. (1997). Protolytic constants of nizatidine, ranitidine and N,N-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation. in Journal of Pharmaceutical and Biomedical Analysis, 15(11), 1667-1678.
https://doi.org/10.1016/S0731-7085(96)01977-2

Dumanović D, Juranić IO, Dželetović D, Vasić VM, Jovanović J. Protolytic constants of nizatidine, ranitidine and N,N-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation. in Journal of Pharmaceutical and Biomedical Analysis. 1997;15(11):1667-1678.
doi:10.1016/S0731-7085(96)01977-2 .

Dumanović, Dragica, Juranić, Ivan O., Dželetović, D., Vasić, Vesna M., Jovanović, J., "Protolytic constants of nizatidine, ranitidine and N,N-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation" in Journal of Pharmaceutical and Biomedical Analysis, 15, no. 11 (1997):1667-1678,
https://doi.org/10.1016/S0731-7085(96)01977-2 . .