TY  - JOUR
AU  - Periša, Jovana
AU  - Lenhardt Acković, Lea
AU  - Jovanović, Dragana J.
AU  - Dramićanin, Miroslav
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0925346719300345
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8043
AB  - EuPO4 and Eu3+-activated REPO4 (RE = La, Dy, Er) ultrasmall fluorescent nanoparticles (NPs) with an average diameter of 2.1 nm were prepared via colloidal synthesis and tested for sensing Cu2+ and other heavy-metal ions. The pure monoclinic monazite crystal structure (space group P121/n1) of the synthesized particles was confirmed using X-ray diffraction measurements, and transmission electron microscopy images showed round particles with a narrow particle-size distribution. The NPs exhibited intense red emission, which is characteristic of the f-f electronic transition of Eu3+, and the quenching of their emission in the presence of heavy-metal ions was revealed by dispersing colloidal particles in a TRIS buffer and then performing photoluminescence measurements. Strong quenching of the emission (at a rate of 0.195 μM−1) was observed upon the addition of Cu2+ ions over the concentration range of 0–10 μM with a limit of detection of 60 nM for Cu2+. The recovery of nearly 90% of the original emission intensity of the probe was achieved via the addition of ethylendiaminetetraacetic acid and was possible in five quenching/recovery cycles. © 2019
T2  - Optical Materials
T1  - Detection of Cu2+ ions in aqueous solution via emission quenching of colloidal EuPO4 ultrasmall nanoparticles
VL  - 89
SP  - 142
EP  - 148
DO  - 10.1016/j.optmat.2018.12.059
ER  - 

@article{
author = "Periša, Jovana and Lenhardt Acković, Lea and Jovanović, Dragana J. and Dramićanin, Miroslav",
year = "2019",
abstract = "EuPO4 and Eu3+-activated REPO4 (RE = La, Dy, Er) ultrasmall fluorescent nanoparticles (NPs) with an average diameter of 2.1 nm were prepared via colloidal synthesis and tested for sensing Cu2+ and other heavy-metal ions. The pure monoclinic monazite crystal structure (space group P121/n1) of the synthesized particles was confirmed using X-ray diffraction measurements, and transmission electron microscopy images showed round particles with a narrow particle-size distribution. The NPs exhibited intense red emission, which is characteristic of the f-f electronic transition of Eu3+, and the quenching of their emission in the presence of heavy-metal ions was revealed by dispersing colloidal particles in a TRIS buffer and then performing photoluminescence measurements. Strong quenching of the emission (at a rate of 0.195 μM−1) was observed upon the addition of Cu2+ ions over the concentration range of 0–10 μM with a limit of detection of 60 nM for Cu2+. The recovery of nearly 90% of the original emission intensity of the probe was achieved via the addition of ethylendiaminetetraacetic acid and was possible in five quenching/recovery cycles. © 2019",
journal = "Optical Materials",
title = "Detection of Cu2+ ions in aqueous solution via emission quenching of colloidal EuPO4 ultrasmall nanoparticles",
volume = "89",
pages = "142-148",
doi = "10.1016/j.optmat.2018.12.059"
}

Periša, J., Lenhardt Acković, L., Jovanović, D. J.,& Dramićanin, M.. (2019). Detection of Cu2+ ions in aqueous solution via emission quenching of colloidal EuPO4 ultrasmall nanoparticles. in Optical Materials, 89, 142-148.
https://doi.org/10.1016/j.optmat.2018.12.059

Periša J, Lenhardt Acković L, Jovanović DJ, Dramićanin M. Detection of Cu2+ ions in aqueous solution via emission quenching of colloidal EuPO4 ultrasmall nanoparticles. in Optical Materials. 2019;89:142-148.
doi:10.1016/j.optmat.2018.12.059 .

Periša, Jovana, Lenhardt Acković, Lea, Jovanović, Dragana J., Dramićanin, Miroslav, "Detection of Cu2+ ions in aqueous solution via emission quenching of colloidal EuPO4 ultrasmall nanoparticles" in Optical Materials, 89 (2019):142-148,
https://doi.org/10.1016/j.optmat.2018.12.059 . .

TY  - JOUR
AU  - Dojčilović, Radovan
AU  - Pajović, Jelena D.
AU  - Božanić, Dušan K.
AU  - Jović, Nataša G.
AU  - Pavlović, Vera P.
AU  - Pavlović, Vladimir B.
AU  - Lenhardt Acković, Lea
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Miroslav
AU  - Kaščakova, Slavka
AU  - Refregiers, Matthieu
AU  - Rašić, Goran
AU  - Vlahović, Branislav
AU  - Đoković, Vladimir
PY  - 2018
UR  - http://stacks.iop.org/2053-1583/5/i=4/a=045019?key=crossref.f455f07bdfb3469c8077963ff0f38f95
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7909
AB  - The interaction of partially reduced graphene oxide (prGO) and Huh7.5.1 liver cancer cells was investigated by means of DUV fluorescence bioimaging. The prGO sample was obtained by the reduction (to a certain extent) of the initially prepared graphene oxide (GO) nanosheets with hydrazine. The fluorescence of the GO nanosheets increases with time of the reduction due to a change in ratio of the sp2 and sp3 carbon sites and the prGO sample was extracted from the dispersion after 6 min, when the intensity of the fluorescence reached its maximum. The reduction process was left to proceed further to saturation until highly reduced graphene oxide (denoted here as rGO) was obtained. GO, prGO and rGO samples were investigated by structural (scanning electron microscopy (SEM), scanning transmission electron microscopy coupled with energy dispersive spectrometry (STEM-EDS)) and spectroscopic (UV-vis, photoluminescence (PL), Raman) methods. After that, Huh7.5.1 cells were incubated with GO, prGO and rGO nanosheets and used in bioimaging studies, which were performed on DISCO beamline of synchrotron SOLEIL. It was found that the prGO significantly enhanced the fluorescence of the cells and increased the intensity of the signal by ~2.5 times. Time-lapse fluorescence microscopy experiments showed that fluorescence dynamics strongly depends on the type of nanosheets used. The obtained prGO nanostructure can be easily conjugated with aromatic ring containing drugs, which opens a possibility for its applications in fluorescence microscopy monitored drug delivery. © 2018 IOP Publishing Ltd.
T2  - 2D Materials
T1  - DUV fluorescence bioimaging study of the interaction of partially reduced graphene oxide and liver cancer cells
VL  - 5
IS  - 4
SP  - 045019
DO  - 10.1088/2053-1583/aad72b
ER  - 

@article{
author = "Dojčilović, Radovan and Pajović, Jelena D. and Božanić, Dušan K. and Jović, Nataša G. and Pavlović, Vera P. and Pavlović, Vladimir B. and Lenhardt Acković, Lea and Zeković, Ivana Lj. and Dramićanin, Miroslav and Kaščakova, Slavka and Refregiers, Matthieu and Rašić, Goran and Vlahović, Branislav and Đoković, Vladimir",
year = "2018",
abstract = "The interaction of partially reduced graphene oxide (prGO) and Huh7.5.1 liver cancer cells was investigated by means of DUV fluorescence bioimaging. The prGO sample was obtained by the reduction (to a certain extent) of the initially prepared graphene oxide (GO) nanosheets with hydrazine. The fluorescence of the GO nanosheets increases with time of the reduction due to a change in ratio of the sp2 and sp3 carbon sites and the prGO sample was extracted from the dispersion after 6 min, when the intensity of the fluorescence reached its maximum. The reduction process was left to proceed further to saturation until highly reduced graphene oxide (denoted here as rGO) was obtained. GO, prGO and rGO samples were investigated by structural (scanning electron microscopy (SEM), scanning transmission electron microscopy coupled with energy dispersive spectrometry (STEM-EDS)) and spectroscopic (UV-vis, photoluminescence (PL), Raman) methods. After that, Huh7.5.1 cells were incubated with GO, prGO and rGO nanosheets and used in bioimaging studies, which were performed on DISCO beamline of synchrotron SOLEIL. It was found that the prGO significantly enhanced the fluorescence of the cells and increased the intensity of the signal by ~2.5 times. Time-lapse fluorescence microscopy experiments showed that fluorescence dynamics strongly depends on the type of nanosheets used. The obtained prGO nanostructure can be easily conjugated with aromatic ring containing drugs, which opens a possibility for its applications in fluorescence microscopy monitored drug delivery. © 2018 IOP Publishing Ltd.",
journal = "2D Materials",
title = "DUV fluorescence bioimaging study of the interaction of partially reduced graphene oxide and liver cancer cells",
volume = "5",
number = "4",
pages = "045019",
doi = "10.1088/2053-1583/aad72b"
}

Dojčilović, R., Pajović, J. D., Božanić, D. K., Jović, N. G., Pavlović, V. P., Pavlović, V. B., Lenhardt Acković, L., Zeković, I. Lj., Dramićanin, M., Kaščakova, S., Refregiers, M., Rašić, G., Vlahović, B.,& Đoković, V.. (2018). DUV fluorescence bioimaging study of the interaction of partially reduced graphene oxide and liver cancer cells. in 2D Materials, 5(4), 045019.
https://doi.org/10.1088/2053-1583/aad72b

Dojčilović R, Pajović JD, Božanić DK, Jović NG, Pavlović VP, Pavlović VB, Lenhardt Acković L, Zeković IL, Dramićanin M, Kaščakova S, Refregiers M, Rašić G, Vlahović B, Đoković V. DUV fluorescence bioimaging study of the interaction of partially reduced graphene oxide and liver cancer cells. in 2D Materials. 2018;5(4):045019.
doi:10.1088/2053-1583/aad72b .

Dojčilović, Radovan, Pajović, Jelena D., Božanić, Dušan K., Jović, Nataša G., Pavlović, Vera P., Pavlović, Vladimir B., Lenhardt Acković, Lea, Zeković, Ivana Lj., Dramićanin, Miroslav, Kaščakova, Slavka, Refregiers, Matthieu, Rašić, Goran, Vlahović, Branislav, Đoković, Vladimir, "DUV fluorescence bioimaging study of the interaction of partially reduced graphene oxide and liver cancer cells" in 2D Materials, 5, no. 4 (2018):045019,
https://doi.org/10.1088/2053-1583/aad72b . .

TY  - JOUR
AU  - Antonov, Milica
AU  - Lenhardt, Lea I.
AU  - Manojlović, Dragica
AU  - Milićević, Bojana R.
AU  - Dramićanin, Miroslav
PY  - 2018
UR  - http://www.doiserbia.nb.rs/Article.aspx?ID=0042-84501600394A
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7927
AB  - Background/Aim. Discoloration of dental restorations makes them aesthetically unacceptable and is a frequent reason for replacement of composite restorations. The aim of this study was to evaluate changes of color and fluorescence of resin-based composites (RBCs) exposed to natural juices and energy drinks. Methods. Microhybrid composite Gradia Direct™ Extra Bleach White disc-shaped specimens (n = 35) were immersed in three different natural juices and four different energy drinks. Absorption spectra of natural juices and energy drinks, diffuse reflection and fluorescence of composite samples were measured prior and after seven-day immersion by spectrophotometer Thermo Evolution 600 and spectrofluorometer Fluorolog-3-221. Composite’s color was calculated from diffuse reflection spectra and expressed in CIELAB color space (Commission International de l’Eclairage). Results. All natural juices and energy drinks induced color change of resin based composites, but to the different extent. Only aronia and carrot juices induced total color change considerably higher than clinically acceptable threshold, 9.3 and 6.2, respectively. All energy drinks and aronia juice induced notable decrease in fluorescence; the highest change of 28% was evidenced in the case of aronia juice. Conclusion. Change of color and fluorescence will appear differently with various solutions due to different chemical composition and concentration of colorant species in different beverages. Solutions with higher optical absorption induced higher total color change. Discoloration of composites in aronia and carrot juices is similar to those earlier reported for red wine, tea and coffee.
T2  - Vojnosanitetski pregled
T1  - Discoloration of resin based composites in natural juices and energy drinks
T1  - Prebojavanje kompozita prirodnim sokovima i energetskim pićima
VL  - 75
IS  - 8
SP  - 787
EP  - 794
DO  - 10.2298/VSP161018394A
ER  - 

@article{
author = "Antonov, Milica and Lenhardt, Lea I. and Manojlović, Dragica and Milićević, Bojana R. and Dramićanin, Miroslav",
year = "2018",
abstract = "Background/Aim. Discoloration of dental restorations makes them aesthetically unacceptable and is a frequent reason for replacement of composite restorations. The aim of this study was to evaluate changes of color and fluorescence of resin-based composites (RBCs) exposed to natural juices and energy drinks. Methods. Microhybrid composite Gradia Direct™ Extra Bleach White disc-shaped specimens (n = 35) were immersed in three different natural juices and four different energy drinks. Absorption spectra of natural juices and energy drinks, diffuse reflection and fluorescence of composite samples were measured prior and after seven-day immersion by spectrophotometer Thermo Evolution 600 and spectrofluorometer Fluorolog-3-221. Composite’s color was calculated from diffuse reflection spectra and expressed in CIELAB color space (Commission International de l’Eclairage). Results. All natural juices and energy drinks induced color change of resin based composites, but to the different extent. Only aronia and carrot juices induced total color change considerably higher than clinically acceptable threshold, 9.3 and 6.2, respectively. All energy drinks and aronia juice induced notable decrease in fluorescence; the highest change of 28% was evidenced in the case of aronia juice. Conclusion. Change of color and fluorescence will appear differently with various solutions due to different chemical composition and concentration of colorant species in different beverages. Solutions with higher optical absorption induced higher total color change. Discoloration of composites in aronia and carrot juices is similar to those earlier reported for red wine, tea and coffee.",
journal = "Vojnosanitetski pregled",
title = "Discoloration of resin based composites in natural juices and energy drinks, Prebojavanje kompozita prirodnim sokovima i energetskim pićima",
volume = "75",
number = "8",
pages = "787-794",
doi = "10.2298/VSP161018394A"
}

Antonov, M., Lenhardt, L. I., Manojlović, D., Milićević, B. R.,& Dramićanin, M.. (2018). Discoloration of resin based composites in natural juices and energy drinks. in Vojnosanitetski pregled, 75(8), 787-794.
https://doi.org/10.2298/VSP161018394A

Antonov M, Lenhardt LI, Manojlović D, Milićević BR, Dramićanin M. Discoloration of resin based composites in natural juices and energy drinks. in Vojnosanitetski pregled. 2018;75(8):787-794.
doi:10.2298/VSP161018394A .

Antonov, Milica, Lenhardt, Lea I., Manojlović, Dragica, Milićević, Bojana R., Dramićanin, Miroslav, "Discoloration of resin based composites in natural juices and energy drinks" in Vojnosanitetski pregled, 75, no. 8 (2018):787-794,
https://doi.org/10.2298/VSP161018394A . .

TY  - JOUR
AU  - Dramićanin, Tatjana
AU  - Lenhardt Acković, Lea
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Miroslav
PY  - 2018
UR  - https://www.hindawi.com/journals/jspec/2018/8395212/
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7800
AB  - Honey is a frequent target of adulteration through inappropriate production practices and origin mislabelling. Current methods for the detection of adulterated honey are time and labor consuming, require highly skilled personnel, and lengthy sample preparation. Fluorescence spectroscopy overcomes such drawbacks, as it is fast and noncontact and requires minimal sample preparation. In this paper, the application of fluorescence spectroscopy coupled with statistical tools for the detection of adulterated honey is demonstrated. For this purpose, fluorescence excitation-emission matrices were measured for 99 samples of different types of natural honey and 15 adulterated honey samples (in 3 technical replicas for each sample). Statistical t -test showed that significant differences between fluorescence of natural and adulterated honey samples exist in 5 spectral regions: (1) excitation: 240–265 nm, emission: 370–495 nm; (2) excitation: 280–320 nm, emission: 390–470 nm; (3) excitation: 260–285 nm, emission: 320–370 nm; (4) excitation: 310–360 nm, emission: 370–470 nm; and (5) excitation: 375–435 nm, emission: 440–520 nm, in which majority of fluorescence comes from the aromatic amino acids, phenolic compounds, and fluorescent Maillard reaction products. Principal component analysis confirmed these findings and showed that 90% of variance in fluorescence is accumulated in the first two principal components, which can be used for the discrimination of fake honey samples. The classification of honey from fluorescence data is demonstrated with a linear discriminant analysis (LDA). When subjected to LDA, total fluorescence intensities of selected spectral regions provided classification of honey (natural or adulterated) with 100% accuracy. In addition, it is demonstrated that intensities of honey emissions in each of these spectral regions may serve as criteria for the discrimination between natural and fake honey.
T2  - Journal of Spectroscopy
T1  - Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices
VL  - 2018
SP  - 1
EP  - 6
DO  - 10.1155/2018/8395212
ER  - 

@article{
author = "Dramićanin, Tatjana and Lenhardt Acković, Lea and Zeković, Ivana Lj. and Dramićanin, Miroslav",
year = "2018",
abstract = "Honey is a frequent target of adulteration through inappropriate production practices and origin mislabelling. Current methods for the detection of adulterated honey are time and labor consuming, require highly skilled personnel, and lengthy sample preparation. Fluorescence spectroscopy overcomes such drawbacks, as it is fast and noncontact and requires minimal sample preparation. In this paper, the application of fluorescence spectroscopy coupled with statistical tools for the detection of adulterated honey is demonstrated. For this purpose, fluorescence excitation-emission matrices were measured for 99 samples of different types of natural honey and 15 adulterated honey samples (in 3 technical replicas for each sample). Statistical t -test showed that significant differences between fluorescence of natural and adulterated honey samples exist in 5 spectral regions: (1) excitation: 240–265 nm, emission: 370–495 nm; (2) excitation: 280–320 nm, emission: 390–470 nm; (3) excitation: 260–285 nm, emission: 320–370 nm; (4) excitation: 310–360 nm, emission: 370–470 nm; and (5) excitation: 375–435 nm, emission: 440–520 nm, in which majority of fluorescence comes from the aromatic amino acids, phenolic compounds, and fluorescent Maillard reaction products. Principal component analysis confirmed these findings and showed that 90% of variance in fluorescence is accumulated in the first two principal components, which can be used for the discrimination of fake honey samples. The classification of honey from fluorescence data is demonstrated with a linear discriminant analysis (LDA). When subjected to LDA, total fluorescence intensities of selected spectral regions provided classification of honey (natural or adulterated) with 100% accuracy. In addition, it is demonstrated that intensities of honey emissions in each of these spectral regions may serve as criteria for the discrimination between natural and fake honey.",
journal = "Journal of Spectroscopy",
title = "Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices",
volume = "2018",
pages = "1-6",
doi = "10.1155/2018/8395212"
}

Dramićanin, T., Lenhardt Acković, L., Zeković, I. Lj.,& Dramićanin, M.. (2018). Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices. in Journal of Spectroscopy, 2018, 1-6.
https://doi.org/10.1155/2018/8395212

Dramićanin T, Lenhardt Acković L, Zeković IL, Dramićanin M. Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices. in Journal of Spectroscopy. 2018;2018:1-6.
doi:10.1155/2018/8395212 .

Dramićanin, Tatjana, Lenhardt Acković, Lea, Zeković, Ivana Lj., Dramićanin, Miroslav, "Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices" in Journal of Spectroscopy, 2018 (2018):1-6,
https://doi.org/10.1155/2018/8395212 . .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Milićević, Bojana R.
AU  - Burojević, Jovana
AU  - Dramićanin, Miroslav
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1535
AB  - This paper presents parallel factor analysis (PARAFAC) of fluorescence of cereal flours. Excitation emission matrices (EEMs) of different cereal flours (wheat, corn, rye, rice, oat, spelt, barley and buckwheat) were measured in a front-face configuration over the ultraviolet-visible spectral range. EEMs showed that flours strongly fluoresce in two spectral regions, where amino acids, tocopherols, pyridoxine and 4-aminobenzoic acid show intense emissions. 4-component PARAFAC was used to model flour fluorescence and to decompose EEMs into excitation and emission spectra of each component. PARAFAC also provided relative concentrations of these components. The largest differences between flours were found in the concentration levels of the first and third component. Finally, variations in concentrations of PARAFAC modelled components were analysed in relation to the botanical origin of flour samples. (C) 2017 Elsevier Ltd. All rights reserved.
T2  - Food Chemistry
T1  - Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC
VL  - 229
SP  - 165
EP  - 171
DO  - 10.1016/j.foodchem.2017.02.070
ER  - 

@article{
author = "Lenhardt, Lea I. and Zeković, Ivana Lj. and Dramićanin, Tatjana and Milićević, Bojana R. and Burojević, Jovana and Dramićanin, Miroslav",
year = "2017",
abstract = "This paper presents parallel factor analysis (PARAFAC) of fluorescence of cereal flours. Excitation emission matrices (EEMs) of different cereal flours (wheat, corn, rye, rice, oat, spelt, barley and buckwheat) were measured in a front-face configuration over the ultraviolet-visible spectral range. EEMs showed that flours strongly fluoresce in two spectral regions, where amino acids, tocopherols, pyridoxine and 4-aminobenzoic acid show intense emissions. 4-component PARAFAC was used to model flour fluorescence and to decompose EEMs into excitation and emission spectra of each component. PARAFAC also provided relative concentrations of these components. The largest differences between flours were found in the concentration levels of the first and third component. Finally, variations in concentrations of PARAFAC modelled components were analysed in relation to the botanical origin of flour samples. (C) 2017 Elsevier Ltd. All rights reserved.",
journal = "Food Chemistry",
title = "Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC",
volume = "229",
pages = "165-171",
doi = "10.1016/j.foodchem.2017.02.070"
}

Lenhardt, L. I., Zeković, I. Lj., Dramićanin, T., Milićević, B. R., Burojević, J.,& Dramićanin, M.. (2017). Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC. in Food Chemistry, 229, 165-171.
https://doi.org/10.1016/j.foodchem.2017.02.070

Lenhardt LI, Zeković IL, Dramićanin T, Milićević BR, Burojević J, Dramićanin M. Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC. in Food Chemistry. 2017;229:165-171.
doi:10.1016/j.foodchem.2017.02.070 .

Lenhardt, Lea I., Zeković, Ivana Lj., Dramićanin, Tatjana, Milićević, Bojana R., Burojević, Jovana, Dramićanin, Miroslav, "Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC" in Food Chemistry, 229 (2017):165-171,
https://doi.org/10.1016/j.foodchem.2017.02.070 . .

TY  - JOUR
AU  - Antonov, Milica
AU  - Lenhardt, Lea I.
AU  - Manojlović, Dragica
AU  - Milićević, Bojana R.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Miroslav
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1281
AB  - ObjectiveThe aim of this study was to evaluate changes of color and fluorescence of resin based composite exposed to beer. Materials and Methods84 samples (13 mm in diameter and 1.5 mm thick) of microhybrid composite Gradia Direct(TM) extra bleach white were immersed in 5 different beers (dark and light) or distilled water. Color and fluorescence were measured prior and after 1-, 7-, and 14-day immersion by Spectrophotometer Thermo Evolution 600 and Fluorolog-3-221 spectrofluorometer. ResultsResin based composites changed color after immersion in beers of different types. Beers with higher optical absorption induced greater color changes. The fluorescence intensity of composites was decreased after immersion in beer, but the shape of fluorescence spectra was not changed. 14-day immersion in Bernard dark beer caused the greatest changes in optical properties of composite: E*=9.0 and 57.6% reduced fluorescence. ConclusionDark and light beers changed optical properties of resin based composite. The color change come exclusively from the change of chroma. Clinical SignificanceTo fully meet esthetic criteria when using dental materials in restoration it is crucial to match optical properties of teeth and dental restoration at the moment of placement, but also to keep the match over the time. Considering that staining in beer causes changes in color and fluorescence of composites and that discoloration is a frequent reason for replacement of composite restorations, the data and conclusions on discoloration of dental restorations caused by beer consumption should aid dental professionals when reaching for high esthetics of modern dentistry.(J Esthet Restor Dent 28:330-338, 2016)
T2  - Journal of Esthetic and Restorative Dentistry
T1  - Changes of Color and Fluorescence of Resin Composites Immersed in Beer
VL  - 28
IS  - 5
SP  - 330
EP  - 338
DO  - 10.1111/jerd.12232
ER  - 

@article{
author = "Antonov, Milica and Lenhardt, Lea I. and Manojlović, Dragica and Milićević, Bojana R. and Zeković, Ivana Lj. and Dramićanin, Miroslav",
year = "2016",
abstract = "ObjectiveThe aim of this study was to evaluate changes of color and fluorescence of resin based composite exposed to beer. Materials and Methods84 samples (13 mm in diameter and 1.5 mm thick) of microhybrid composite Gradia Direct(TM) extra bleach white were immersed in 5 different beers (dark and light) or distilled water. Color and fluorescence were measured prior and after 1-, 7-, and 14-day immersion by Spectrophotometer Thermo Evolution 600 and Fluorolog-3-221 spectrofluorometer. ResultsResin based composites changed color after immersion in beers of different types. Beers with higher optical absorption induced greater color changes. The fluorescence intensity of composites was decreased after immersion in beer, but the shape of fluorescence spectra was not changed. 14-day immersion in Bernard dark beer caused the greatest changes in optical properties of composite: E*=9.0 and 57.6% reduced fluorescence. ConclusionDark and light beers changed optical properties of resin based composite. The color change come exclusively from the change of chroma. Clinical SignificanceTo fully meet esthetic criteria when using dental materials in restoration it is crucial to match optical properties of teeth and dental restoration at the moment of placement, but also to keep the match over the time. Considering that staining in beer causes changes in color and fluorescence of composites and that discoloration is a frequent reason for replacement of composite restorations, the data and conclusions on discoloration of dental restorations caused by beer consumption should aid dental professionals when reaching for high esthetics of modern dentistry.(J Esthet Restor Dent 28:330-338, 2016)",
journal = "Journal of Esthetic and Restorative Dentistry",
title = "Changes of Color and Fluorescence of Resin Composites Immersed in Beer",
volume = "28",
number = "5",
pages = "330-338",
doi = "10.1111/jerd.12232"
}

Antonov, M., Lenhardt, L. I., Manojlović, D., Milićević, B. R., Zeković, I. Lj.,& Dramićanin, M.. (2016). Changes of Color and Fluorescence of Resin Composites Immersed in Beer. in Journal of Esthetic and Restorative Dentistry, 28(5), 330-338.
https://doi.org/10.1111/jerd.12232

Antonov M, Lenhardt LI, Manojlović D, Milićević BR, Zeković IL, Dramićanin M. Changes of Color and Fluorescence of Resin Composites Immersed in Beer. in Journal of Esthetic and Restorative Dentistry. 2016;28(5):330-338.
doi:10.1111/jerd.12232 .

Antonov, Milica, Lenhardt, Lea I., Manojlović, Dragica, Milićević, Bojana R., Zeković, Ivana Lj., Dramićanin, Miroslav, "Changes of Color and Fluorescence of Resin Composites Immersed in Beer" in Journal of Esthetic and Restorative Dentistry, 28, no. 5 (2016):330-338,
https://doi.org/10.1111/jerd.12232 . .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Dramićanin, Miroslav
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/831
AB  - Parallel factor analysis (PARAFAC) was demonstrated as a tool for the analysis of the time-resolved emission spectra of mixtures of rare-earth phosphors. The time-resolved luminescence spectra of mixtures of europium(III)-doped Gd2O3, Gd2Ti2O7, and GdVO4 powders were measured in the 570-650 nm emission range with time delays varying between 0 and 10 ms. Then, PARAFAC was applied to decompose the time-resolved spectra of the mixtures into the emission spectra and emission decay profiles of the individual phosphors. The second-order advantage of this method was demonstrated by calculating the concentrations of the phosphors in the mixtures after calibrating the PARAFAC model by using samples of known concentrations. This method offered 0.1% detection limit and an average prediction error of 0.034%. (C)) 2015 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Journal of Luminescence
T1  - PARAFAC: A tool for the analysis of phosphor mixture luminescence
VL  - 170
SP  - 136
EP  - 140
DO  - 10.1016/j.jlumin.2015.10.030
ER  - 

@article{
author = "Lenhardt, Lea I. and Dramićanin, Miroslav",
year = "2016",
abstract = "Parallel factor analysis (PARAFAC) was demonstrated as a tool for the analysis of the time-resolved emission spectra of mixtures of rare-earth phosphors. The time-resolved luminescence spectra of mixtures of europium(III)-doped Gd2O3, Gd2Ti2O7, and GdVO4 powders were measured in the 570-650 nm emission range with time delays varying between 0 and 10 ms. Then, PARAFAC was applied to decompose the time-resolved spectra of the mixtures into the emission spectra and emission decay profiles of the individual phosphors. The second-order advantage of this method was demonstrated by calculating the concentrations of the phosphors in the mixtures after calibrating the PARAFAC model by using samples of known concentrations. This method offered 0.1% detection limit and an average prediction error of 0.034%. (C)) 2015 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Journal of Luminescence",
title = "PARAFAC: A tool for the analysis of phosphor mixture luminescence",
volume = "170",
pages = "136-140",
doi = "10.1016/j.jlumin.2015.10.030"
}

Lenhardt, L. I.,& Dramićanin, M.. (2016). PARAFAC: A tool for the analysis of phosphor mixture luminescence. in Journal of Luminescence
Elsevier., 170, 136-140.
https://doi.org/10.1016/j.jlumin.2015.10.030

Lenhardt LI, Dramićanin M. PARAFAC: A tool for the analysis of phosphor mixture luminescence. in Journal of Luminescence. 2016;170:136-140.
doi:10.1016/j.jlumin.2015.10.030 .

Lenhardt, Lea I., Dramićanin, Miroslav, "PARAFAC: A tool for the analysis of phosphor mixture luminescence" in Journal of Luminescence, 170 (2016):136-140,
https://doi.org/10.1016/j.jlumin.2015.10.030 . .

TY  - JOUR
AU  - Manojlović, Dragan D.
AU  - Lenhardt, Lea I.
AU  - Milićević, Bojana R.
AU  - Antonov, Milica
AU  - Miletic, V.
AU  - Dramićanin, Miroslav
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/763
AB  - Colour changes in Gradia Direct (TM) composite after immersion in tea, coffee, red wine, Coca-Cola, Colgate mouthwash, and distilled water were evaluated using principal component analysis (PCA) and the CIELAB colour coordinates. The reflection spectra of the composites were used as input data for the PCA. The output data (scores and loadings) provided information about the magnitude and origin of the surface reflection changes after exposure to the staining solutions. The reflection spectra of the stained samples generally exhibited lower reflection in the blue spectral range, which was manifested in the lower content of the blue shade for the samples. Both analyses demonstrated the high staining abilities of tea, coffee, and red wine, which produced total colour changes of 4.31, 6.61, and 6.22, respectively, according to the CIELAB analysis. PCA revealed subtle changes in the reflection spectra of composites immersed in Coca-Cola, demonstrating Coca-Colas ability to stain the composite to a small degree.
T2  - Scientific Reports
T1  - Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis
VL  - 5
DO  - 10.1038/srep14638
ER  - 

@article{
author = "Manojlović, Dragan D. and Lenhardt, Lea I. and Milićević, Bojana R. and Antonov, Milica and Miletic, V. and Dramićanin, Miroslav",
year = "2015",
abstract = "Colour changes in Gradia Direct (TM) composite after immersion in tea, coffee, red wine, Coca-Cola, Colgate mouthwash, and distilled water were evaluated using principal component analysis (PCA) and the CIELAB colour coordinates. The reflection spectra of the composites were used as input data for the PCA. The output data (scores and loadings) provided information about the magnitude and origin of the surface reflection changes after exposure to the staining solutions. The reflection spectra of the stained samples generally exhibited lower reflection in the blue spectral range, which was manifested in the lower content of the blue shade for the samples. Both analyses demonstrated the high staining abilities of tea, coffee, and red wine, which produced total colour changes of 4.31, 6.61, and 6.22, respectively, according to the CIELAB analysis. PCA revealed subtle changes in the reflection spectra of composites immersed in Coca-Cola, demonstrating Coca-Colas ability to stain the composite to a small degree.",
journal = "Scientific Reports",
title = "Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis",
volume = "5",
doi = "10.1038/srep14638"
}

Manojlović, D. D., Lenhardt, L. I., Milićević, B. R., Antonov, M., Miletic, V.,& Dramićanin, M.. (2015). Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis. in Scientific Reports, 5.
https://doi.org/10.1038/srep14638

Manojlović DD, Lenhardt LI, Milićević BR, Antonov M, Miletic V, Dramićanin M. Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis. in Scientific Reports. 2015;5.
doi:10.1038/srep14638 .

Manojlović, Dragan D., Lenhardt, Lea I., Milićević, Bojana R., Antonov, Milica, Miletic, V., Dramićanin, Miroslav, "Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis" in Scientific Reports, 5 (2015),
https://doi.org/10.1038/srep14638 . .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Bro, Rasmus
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Dramićanin, Miroslav
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/382
AB  - Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) and Partial least squares Discriminant Analysis (PLS DA) were used for characterization and classification of honey. Excitation emission spectra were obtained for 95 honey samples of different botanical origin (acacia, sunflower, linden, meadow, and fake honey) by recording emission from 270 to 640 nm with excitation in the range of 240-500 nm. The number of fluorophores present in honey, excitation and emission spectra of each fluorophore, and their relative concentration are determined using a six-component PARAFAC model. Emissions from phenolic compounds and Maillard reaction products exhibited the largest difference among classes of honey of different botanical origin. The PLS DA classification model, constructed from PARAFAC model scores, detected fake honey samples with 100% sensitivity and specificity. Honey samples were also classified using PLS DA with errors of 0.5% for linden, 10% for acacia, and about 20% for both sunflower and meadow mix. (c) 2014 Elsevier Ltd. All rights reserved.
T2  - Food Chemistry
T1  - Fluorescence spectroscopy coupled with PARAFAC and PLS DA for characterization and classification of honey
VL  - 175
SP  - 284
EP  - 291
DO  - 10.1016/j.foodchem.2014.11.162
ER  - 

@article{
author = "Lenhardt, Lea I. and Bro, Rasmus and Zeković, Ivana Lj. and Dramićanin, Tatjana and Dramićanin, Miroslav",
year = "2015",
abstract = "Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) and Partial least squares Discriminant Analysis (PLS DA) were used for characterization and classification of honey. Excitation emission spectra were obtained for 95 honey samples of different botanical origin (acacia, sunflower, linden, meadow, and fake honey) by recording emission from 270 to 640 nm with excitation in the range of 240-500 nm. The number of fluorophores present in honey, excitation and emission spectra of each fluorophore, and their relative concentration are determined using a six-component PARAFAC model. Emissions from phenolic compounds and Maillard reaction products exhibited the largest difference among classes of honey of different botanical origin. The PLS DA classification model, constructed from PARAFAC model scores, detected fake honey samples with 100% sensitivity and specificity. Honey samples were also classified using PLS DA with errors of 0.5% for linden, 10% for acacia, and about 20% for both sunflower and meadow mix. (c) 2014 Elsevier Ltd. All rights reserved.",
journal = "Food Chemistry",
title = "Fluorescence spectroscopy coupled with PARAFAC and PLS DA for characterization and classification of honey",
volume = "175",
pages = "284-291",
doi = "10.1016/j.foodchem.2014.11.162"
}

Lenhardt, L. I., Bro, R., Zeković, I. Lj., Dramićanin, T.,& Dramićanin, M.. (2015). Fluorescence spectroscopy coupled with PARAFAC and PLS DA for characterization and classification of honey. in Food Chemistry, 175, 284-291.
https://doi.org/10.1016/j.foodchem.2014.11.162

Lenhardt LI, Bro R, Zeković IL, Dramićanin T, Dramićanin M. Fluorescence spectroscopy coupled with PARAFAC and PLS DA for characterization and classification of honey. in Food Chemistry. 2015;175:284-291.
doi:10.1016/j.foodchem.2014.11.162 .

Lenhardt, Lea I., Bro, Rasmus, Zeković, Ivana Lj., Dramićanin, Tatjana, Dramićanin, Miroslav, "Fluorescence spectroscopy coupled with PARAFAC and PLS DA for characterization and classification of honey" in Food Chemistry, 175 (2015):284-291,
https://doi.org/10.1016/j.foodchem.2014.11.162 . .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Dramićanin, Miroslav
AU  - Bro, Rasmus
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5981
AB  - Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral (linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240-500 nm for synchronous wavelength intervals of 30-300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.
T2  - Applied Spectroscopy
T1  - Determination of the Botanical Origin of Honey by Front-Face Synchronous Fluorescence Spectroscopy
VL  - 68
IS  - 5
SP  - 557
EP  - 563
DO  - 10.1366/13-07325
ER  - 

@article{
author = "Lenhardt, Lea I. and Zeković, Ivana Lj. and Dramićanin, Tatjana and Dramićanin, Miroslav and Bro, Rasmus",
year = "2014",
abstract = "Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral (linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240-500 nm for synchronous wavelength intervals of 30-300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.",
journal = "Applied Spectroscopy",
title = "Determination of the Botanical Origin of Honey by Front-Face Synchronous Fluorescence Spectroscopy",
volume = "68",
number = "5",
pages = "557-563",
doi = "10.1366/13-07325"
}

Lenhardt, L. I., Zeković, I. Lj., Dramićanin, T., Dramićanin, M.,& Bro, R.. (2014). Determination of the Botanical Origin of Honey by Front-Face Synchronous Fluorescence Spectroscopy. in Applied Spectroscopy, 68(5), 557-563.
https://doi.org/10.1366/13-07325

Lenhardt LI, Zeković IL, Dramićanin T, Dramićanin M, Bro R. Determination of the Botanical Origin of Honey by Front-Face Synchronous Fluorescence Spectroscopy. in Applied Spectroscopy. 2014;68(5):557-563.
doi:10.1366/13-07325 .

Lenhardt, Lea I., Zeković, Ivana Lj., Dramićanin, Tatjana, Dramićanin, Miroslav, Bro, Rasmus, "Determination of the Botanical Origin of Honey by Front-Face Synchronous Fluorescence Spectroscopy" in Applied Spectroscopy, 68, no. 5 (2014):557-563,
https://doi.org/10.1366/13-07325 . .

TY  - JOUR
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Lenhardt, Lea I.
AU  - Bandic, Jadran
AU  - Dramićanin, Miroslav
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6088
AB  - Novel optical spectroscopy and imaging methods may be valuable in the early detection of cancer. This paper reports differences in the luminescence responses of pigmented skin lesions (melanomas and nevi) and apparently normal non-pigmented human skin, based on analyses of synchronous luminescence spectroscopy. measurements. Measurements were performed in the excitation range of 330-545 nm, with synchronous intervals varying from 30 120 nm. Normal skin, nevi, and melanomas differ in the way they fluoresce, and these differences are more distinct in the synchronous fluorescence spectra than in the conventional emission and excitation spectra. The differences in the fluorescence characteristics of pigmented and normal skin samples were ascribed to differences in concentrations of endogenous fluorophores and chromophores. Principal component and linear discriminant analysis of the synchronous spectra measured at different synchronous intervals showed that the greatest variance among the sample groups was at the 70 nm interval spectra. These spectra were then used to create partial least squares discriminant analysis-based classification models. Evaluation of the quality of these models from the receiver operating characteristic curves showed they performed well, with a maximum value of 1 for the area under the curve for melanoma detection. Hence, synchronous luminescence spectroscopy coupled with statistical methods may be advantageous in the early detection of skin cancer.
T2  - Applied Spectroscopy
T1  - Discrimination Among Melanoma, Nevi, and Normal Skin by Using Synchronous Luminescence Spectroscopy
VL  - 68
IS  - 8
SP  - 823
EP  - 830
DO  - 10.1366/13-07153
ER  - 

@article{
author = "Zeković, Ivana Lj. and Dramićanin, Tatjana and Lenhardt, Lea I. and Bandic, Jadran and Dramićanin, Miroslav",
year = "2014",
abstract = "Novel optical spectroscopy and imaging methods may be valuable in the early detection of cancer. This paper reports differences in the luminescence responses of pigmented skin lesions (melanomas and nevi) and apparently normal non-pigmented human skin, based on analyses of synchronous luminescence spectroscopy. measurements. Measurements were performed in the excitation range of 330-545 nm, with synchronous intervals varying from 30 120 nm. Normal skin, nevi, and melanomas differ in the way they fluoresce, and these differences are more distinct in the synchronous fluorescence spectra than in the conventional emission and excitation spectra. The differences in the fluorescence characteristics of pigmented and normal skin samples were ascribed to differences in concentrations of endogenous fluorophores and chromophores. Principal component and linear discriminant analysis of the synchronous spectra measured at different synchronous intervals showed that the greatest variance among the sample groups was at the 70 nm interval spectra. These spectra were then used to create partial least squares discriminant analysis-based classification models. Evaluation of the quality of these models from the receiver operating characteristic curves showed they performed well, with a maximum value of 1 for the area under the curve for melanoma detection. Hence, synchronous luminescence spectroscopy coupled with statistical methods may be advantageous in the early detection of skin cancer.",
journal = "Applied Spectroscopy",
title = "Discrimination Among Melanoma, Nevi, and Normal Skin by Using Synchronous Luminescence Spectroscopy",
volume = "68",
number = "8",
pages = "823-830",
doi = "10.1366/13-07153"
}

Zeković, I. Lj., Dramićanin, T., Lenhardt, L. I., Bandic, J.,& Dramićanin, M.. (2014). Discrimination Among Melanoma, Nevi, and Normal Skin by Using Synchronous Luminescence Spectroscopy. in Applied Spectroscopy, 68(8), 823-830.
https://doi.org/10.1366/13-07153

Zeković IL, Dramićanin T, Lenhardt LI, Bandic J, Dramićanin M. Discrimination Among Melanoma, Nevi, and Normal Skin by Using Synchronous Luminescence Spectroscopy. in Applied Spectroscopy. 2014;68(8):823-830.
doi:10.1366/13-07153 .

Zeković, Ivana Lj., Dramićanin, Tatjana, Lenhardt, Lea I., Bandic, Jadran, Dramićanin, Miroslav, "Discrimination Among Melanoma, Nevi, and Normal Skin by Using Synchronous Luminescence Spectroscopy" in Applied Spectroscopy, 68, no. 8 (2014):823-830,
https://doi.org/10.1366/13-07153 . .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Tešić, Živoslav
AU  - Milojković-Opsenica, Dušanka M.
AU  - Dramićanin, Miroslav
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7065
AB  - In recent years, the potential of Fourier-transform infrared spectroscopy coupled with different chemometric tools in food analysis has been established. This technique is rapid, low cost, and reliable and requires little sample preparation. In this work, 130 Serbian unifloral honey samples (linden, acacia, and sunflower types) were analyzed using attenuated total reflectance infrared spectroscopy (ATR-IR). For each spectrum, 64 scans were recorded in wavenumbers between 4000 and 500 cm(-1) and at a spectral resolution of 4 cm(-1). These spectra were analyzed using principal component analysis (PCA), and calculated principal components were then used for support vector machine (SVM) training. In this way, the pattern-recognition tool is obtained for building a classification model for determining the botanical origin of honey. The PCA was used to analyze results and to see if the separation between groups of different types of honeys exists. Using the SVM, the classification model was built and classification errors were acquired. It has been observed that this technique is adequate for determining the botanical origin of honey with a success rate of 98.6%. Based on these results, it can be concluded that this technique offers many possibilities for future rapid qualitative analysis of honey.
T2  - Physica Scripta
T1  - Authentication of the botanical origin of unifloral honey by infrared spectroscopy coupled with support vector machine algorithm
VL  - T162
DO  - 10.1088/0031-8949/2014/T162/014042
ER  - 

@article{
author = "Lenhardt, Lea I. and Zeković, Ivana Lj. and Dramićanin, Tatjana and Tešić, Živoslav and Milojković-Opsenica, Dušanka M. and Dramićanin, Miroslav",
year = "2014",
abstract = "In recent years, the potential of Fourier-transform infrared spectroscopy coupled with different chemometric tools in food analysis has been established. This technique is rapid, low cost, and reliable and requires little sample preparation. In this work, 130 Serbian unifloral honey samples (linden, acacia, and sunflower types) were analyzed using attenuated total reflectance infrared spectroscopy (ATR-IR). For each spectrum, 64 scans were recorded in wavenumbers between 4000 and 500 cm(-1) and at a spectral resolution of 4 cm(-1). These spectra were analyzed using principal component analysis (PCA), and calculated principal components were then used for support vector machine (SVM) training. In this way, the pattern-recognition tool is obtained for building a classification model for determining the botanical origin of honey. The PCA was used to analyze results and to see if the separation between groups of different types of honeys exists. Using the SVM, the classification model was built and classification errors were acquired. It has been observed that this technique is adequate for determining the botanical origin of honey with a success rate of 98.6%. Based on these results, it can be concluded that this technique offers many possibilities for future rapid qualitative analysis of honey.",
journal = "Physica Scripta",
title = "Authentication of the botanical origin of unifloral honey by infrared spectroscopy coupled with support vector machine algorithm",
volume = "T162",
doi = "10.1088/0031-8949/2014/T162/014042"
}

Lenhardt, L. I., Zeković, I. Lj., Dramićanin, T., Tešić, Ž., Milojković-Opsenica, D. M.,& Dramićanin, M.. (2014). Authentication of the botanical origin of unifloral honey by infrared spectroscopy coupled with support vector machine algorithm. in Physica Scripta, T162.
https://doi.org/10.1088/0031-8949/2014/T162/014042

Lenhardt LI, Zeković IL, Dramićanin T, Tešić Ž, Milojković-Opsenica DM, Dramićanin M. Authentication of the botanical origin of unifloral honey by infrared spectroscopy coupled with support vector machine algorithm. in Physica Scripta. 2014;T162.
doi:10.1088/0031-8949/2014/T162/014042 .

Lenhardt, Lea I., Zeković, Ivana Lj., Dramićanin, Tatjana, Tešić, Živoslav, Milojković-Opsenica, Dušanka M., Dramićanin, Miroslav, "Authentication of the botanical origin of unifloral honey by infrared spectroscopy coupled with support vector machine algorithm" in Physica Scripta, T162 (2014),
https://doi.org/10.1088/0031-8949/2014/T162/014042 . .

TY  - THES
AU  - Lenhardt, Lea I.
PY  - 2014
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=3291
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:11733/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=47559439
UR  - http://nardus.mpn.gov.rs/123456789/6020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7293
AB  - Kombinacija optičkih spektroskopskih tehnika i odgovarajućih metoda za analizu imodeliranje spektralnih podataka se pokazala kao veoma obećavajuća tehnika zakarakterizaciju i analizu organskih i neorganskih kompleksnih sistema. Razumevanjefizičkih fenomena koji se javljaju u kompleksnim sistemima predstavlja bitan preduslovza primenu spektroskopskih tehnika u različitim oblastima nauke. U ovoj tezi su izmerenefluorescentne karakteristike četiri kompleksna sistema: tri organska (rastvor vode iaminokiselina, med i tkivo dojke) i jedan neorganski (kompleksni sistem fosfora na baziretkih zemalja). Dobijeni fluorescentni podaci su modelirani primenom paralelnefaktorske analize. Izgrađeni modeli su omogućili definisanje fluorescirajućih komponenti(fluorofora) prisutnih u sistemima, pri čemu je model kao rezultat dao čiste spektre svakepojedinačne fluorofore, kao i njihove relativne koncentracije u svakom od uzorakasistema. U neorganskom sistemu i rastvoru aminokiselina broj fluorofora i njihovekoncentracije su unapred bile poznate i na taj način je testirana uspešnost modela kao injegova sposobnost predikcije prisustva i koncentracija fluorofora u nepoznatimuzorcima. Pokazano je da je dobijeni model veoma uspešan, sa odstupanjem od samo0.036% od stvarne koncentracije kod neorganskog sistema. Za sistem meda, model jepokazao da je u sistemu prisutno 6 fluorofora i dobijeni su čisti spektri svake od njih kaoi njihove relativne koncentracije u svakom pojedinačnom uzorku. Dalje analize spektarameda su ukazale da je na osnovu koncentracija fluorofora moguće odrediti botaničkoporeklo meda. Spektri meda su zatim analizirani metodom glavnih komponenata kao idiskriminantnom analizom parcijalno najmanjih kvadrata. Rezultati su pokazali velikuuspešnost primene metode fluorescentne spektroskopije za klasifikaciju i autentifikacijuuzoraka meda. Proračunom modela tkiva dojke je ustanovljeno da postoje 4 dominantnefluorofore. Utvrđeno je da je na osnovu njihovih koncentracija moguće sa tačnošću od100% odrediti vrstu promena na tkivu (benigno ili maligno). Rezultati su potom poređenisa rezultatima analize potpornih vektora primenjenih na neobrađene spektre, na osnovukojih je pokazano da se sa istim podacima ne može dobiti podjednako uspešan model...
AB  - The combination of optical spectroscopic techniques and appropriate methods foranalysis and modeling of spectral data proved to be a very promising technique for thecharacterization and analysis of organic and inorganic complex systems. Understandingof physical phenomena that occur in complex systems is an essential prerequisite for theapplication of spectroscopic techniques in various fields of science. Fluorescencecharacteristics of four complex systems: three organic (solution of water and amino acids,honey and breast tissue) and one inorganic (a complex system of phosphorus-based rareearth) were measured in this thesis. The obtained fluorescence data were modeled usingparallel factor analysis. The constructed models have enabled definition of the fluorescingcomponents (fluorophores) present in the system, wherein the model as a result gave purespectra of the individual fluorophore as well as their relative concentrations in eachsample of the system. In the inorganic system and solution of amino acids, the number offluorophores and their concentrations were known in advance, and thus the performanceof the model was tested as well as its ability to predict the presence and concentrations offluorophores in the unknown samples. It was shown that the resulting model is verysuccessful, with a deviation of only 0.036% of the actual concentration in inorganicsystems. For the system of honey, the model showed that 6 fluorophores are present inthe system and their pure spectra were obtained, as well as their relative concentrationsin each sample. Further analysis of the spectra of honey have demonstrated that based onthe concentrations of the fluorophores the botanical origin of honey can be determined.Spectra of honey were then analyzed using principal component analysis and discriminantpartial least squares. Results have shown great success in application of fluorescencespectroscopy methods for classification and authentication of honey samples. Based oncalculated model of the breast tissue it was determined that there are four dominantfluorophores. It was estabilshed that based on their concentrations it possible to determinethe type of change in the tissue (benign or malignant) with an accuracy of 100%. Theresults were then compared with the results of support vector machine analysis applied tothe raw spectra, from which it was shown that using the same data successful model cannot be obtained (classification error 35.71%). However, it has been shown that with...
PB  - Универзитет у Београду, Физички факултет
T2  - Универзитет у Београду
T1  - Paralelna faktorska analiza fluorescentnih svojstava višekomponentnih sistema
T1  - Parallel factor analysis of the fluorescent properties of multicomponent systems
UR  - https://hdl.handle.net/21.15107/rcub_nardus_6020
ER  - 

@phdthesis{
author = "Lenhardt, Lea I.",
year = "2014",
abstract = "Kombinacija optičkih spektroskopskih tehnika i odgovarajućih metoda za analizu imodeliranje spektralnih podataka se pokazala kao veoma obećavajuća tehnika zakarakterizaciju i analizu organskih i neorganskih kompleksnih sistema. Razumevanjefizičkih fenomena koji se javljaju u kompleksnim sistemima predstavlja bitan preduslovza primenu spektroskopskih tehnika u različitim oblastima nauke. U ovoj tezi su izmerenefluorescentne karakteristike četiri kompleksna sistema: tri organska (rastvor vode iaminokiselina, med i tkivo dojke) i jedan neorganski (kompleksni sistem fosfora na baziretkih zemalja). Dobijeni fluorescentni podaci su modelirani primenom paralelnefaktorske analize. Izgrađeni modeli su omogućili definisanje fluorescirajućih komponenti(fluorofora) prisutnih u sistemima, pri čemu je model kao rezultat dao čiste spektre svakepojedinačne fluorofore, kao i njihove relativne koncentracije u svakom od uzorakasistema. U neorganskom sistemu i rastvoru aminokiselina broj fluorofora i njihovekoncentracije su unapred bile poznate i na taj način je testirana uspešnost modela kao injegova sposobnost predikcije prisustva i koncentracija fluorofora u nepoznatimuzorcima. Pokazano je da je dobijeni model veoma uspešan, sa odstupanjem od samo0.036% od stvarne koncentracije kod neorganskog sistema. Za sistem meda, model jepokazao da je u sistemu prisutno 6 fluorofora i dobijeni su čisti spektri svake od njih kaoi njihove relativne koncentracije u svakom pojedinačnom uzorku. Dalje analize spektarameda su ukazale da je na osnovu koncentracija fluorofora moguće odrediti botaničkoporeklo meda. Spektri meda su zatim analizirani metodom glavnih komponenata kao idiskriminantnom analizom parcijalno najmanjih kvadrata. Rezultati su pokazali velikuuspešnost primene metode fluorescentne spektroskopije za klasifikaciju i autentifikacijuuzoraka meda. Proračunom modela tkiva dojke je ustanovljeno da postoje 4 dominantnefluorofore. Utvrđeno je da je na osnovu njihovih koncentracija moguće sa tačnošću od100% odrediti vrstu promena na tkivu (benigno ili maligno). Rezultati su potom poređenisa rezultatima analize potpornih vektora primenjenih na neobrađene spektre, na osnovukojih je pokazano da se sa istim podacima ne može dobiti podjednako uspešan model..., The combination of optical spectroscopic techniques and appropriate methods foranalysis and modeling of spectral data proved to be a very promising technique for thecharacterization and analysis of organic and inorganic complex systems. Understandingof physical phenomena that occur in complex systems is an essential prerequisite for theapplication of spectroscopic techniques in various fields of science. Fluorescencecharacteristics of four complex systems: three organic (solution of water and amino acids,honey and breast tissue) and one inorganic (a complex system of phosphorus-based rareearth) were measured in this thesis. The obtained fluorescence data were modeled usingparallel factor analysis. The constructed models have enabled definition of the fluorescingcomponents (fluorophores) present in the system, wherein the model as a result gave purespectra of the individual fluorophore as well as their relative concentrations in eachsample of the system. In the inorganic system and solution of amino acids, the number offluorophores and their concentrations were known in advance, and thus the performanceof the model was tested as well as its ability to predict the presence and concentrations offluorophores in the unknown samples. It was shown that the resulting model is verysuccessful, with a deviation of only 0.036% of the actual concentration in inorganicsystems. For the system of honey, the model showed that 6 fluorophores are present inthe system and their pure spectra were obtained, as well as their relative concentrationsin each sample. Further analysis of the spectra of honey have demonstrated that based onthe concentrations of the fluorophores the botanical origin of honey can be determined.Spectra of honey were then analyzed using principal component analysis and discriminantpartial least squares. Results have shown great success in application of fluorescencespectroscopy methods for classification and authentication of honey samples. Based oncalculated model of the breast tissue it was determined that there are four dominantfluorophores. It was estabilshed that based on their concentrations it possible to determinethe type of change in the tissue (benign or malignant) with an accuracy of 100%. Theresults were then compared with the results of support vector machine analysis applied tothe raw spectra, from which it was shown that using the same data successful model cannot be obtained (classification error 35.71%). However, it has been shown that with...",
publisher = "Универзитет у Београду, Физички факултет",
journal = "Универзитет у Београду",
title = "Paralelna faktorska analiza fluorescentnih svojstava višekomponentnih sistema, Parallel factor analysis of the fluorescent properties of multicomponent systems",
url = "https://hdl.handle.net/21.15107/rcub_nardus_6020"
}

Lenhardt, L. I.. (2014). Paralelna faktorska analiza fluorescentnih svojstava višekomponentnih sistema. in Универзитет у Београду
Универзитет у Београду, Физички факултет..
https://hdl.handle.net/21.15107/rcub_nardus_6020

Lenhardt LI. Paralelna faktorska analiza fluorescentnih svojstava višekomponentnih sistema. in Универзитет у Београду. 2014;.
https://hdl.handle.net/21.15107/rcub_nardus_6020 .

Lenhardt, Lea I., "Paralelna faktorska analiza fluorescentnih svojstava višekomponentnih sistema" in Универзитет у Београду (2014),
https://hdl.handle.net/21.15107/rcub_nardus_6020 .

TY  - JOUR
AU  - Lenhardt, Lea I.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Tatjana
AU  - Dramićanin, Miroslav
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7026
AB  - Over the years various optical spectroscopic techniques have been widely used as diagnostic tools in the discrimination of many types of malignant diseases. Recently, synchronous fluorescent spectroscopy (SFS) coupled with chemometrics has been applied in cancer diagnostics. The SFS method involves simultaneous scanning of both emission and excitation wavelengths while keeping the interval of wavelengths (constant-wavelength mode) or frequencies (constant-energy mode) between them constant. This method is fast, relatively inexpensive, sensitive and non-invasive. Total synchronous fluorescence spectra of normal skin, nevus and melanoma samples were used as input for training of artificial neural networks. Two different types of artificial neural networks were trained, the self-organizing map and the feed-forward neural network. Histopathology results of investigated skin samples were used as the gold standard for network output. Based on the obtained classification success rate of neural networks, we concluded that both networks provided high sensitivity with classification errors between 2 and 4%.
T2  - Physica Scripta
T1  - Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics
VL  - T157
DO  - 10.1088/0031-8949/2013/T157/014057
ER  - 

@article{
author = "Lenhardt, Lea I. and Zeković, Ivana Lj. and Dramićanin, Tatjana and Dramićanin, Miroslav",
year = "2013",
abstract = "Over the years various optical spectroscopic techniques have been widely used as diagnostic tools in the discrimination of many types of malignant diseases. Recently, synchronous fluorescent spectroscopy (SFS) coupled with chemometrics has been applied in cancer diagnostics. The SFS method involves simultaneous scanning of both emission and excitation wavelengths while keeping the interval of wavelengths (constant-wavelength mode) or frequencies (constant-energy mode) between them constant. This method is fast, relatively inexpensive, sensitive and non-invasive. Total synchronous fluorescence spectra of normal skin, nevus and melanoma samples were used as input for training of artificial neural networks. Two different types of artificial neural networks were trained, the self-organizing map and the feed-forward neural network. Histopathology results of investigated skin samples were used as the gold standard for network output. Based on the obtained classification success rate of neural networks, we concluded that both networks provided high sensitivity with classification errors between 2 and 4%.",
journal = "Physica Scripta",
title = "Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics",
volume = "T157",
doi = "10.1088/0031-8949/2013/T157/014057"
}

Lenhardt, L. I., Zeković, I. Lj., Dramićanin, T.,& Dramićanin, M.. (2013). Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics. in Physica Scripta, T157.
https://doi.org/10.1088/0031-8949/2013/T157/014057

Lenhardt LI, Zeković IL, Dramićanin T, Dramićanin M. Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics. in Physica Scripta. 2013;T157.
doi:10.1088/0031-8949/2013/T157/014057 .

Lenhardt, Lea I., Zeković, Ivana Lj., Dramićanin, Tatjana, Dramićanin, Miroslav, "Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics" in Physica Scripta, T157 (2013),
https://doi.org/10.1088/0031-8949/2013/T157/014057 . .

TY  - JOUR
AU  - Dramićanin, Tatjana
AU  - Lenhardt, Lea I.
AU  - Zeković, Ivana Lj.
AU  - Dramićanin, Miroslav
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5020
AB  - Excitation-emission matrices (EEM) and total synchronous fluorescence spectra (SFS) of normal and malignant breast tissue specimens are measured in UV-VIS spectral region to serve as data inputs in development of Support Vector Machine (SVM) based breast cancer diagnostics tool. Various input data combinations are tested for classification accuracy using SVM prediction against histopathology findings to discover the best combination regarding diagnostics sensitivity and specificity. It is shown that with EEM data SVM provided 67 % sensitivity and 62 % specificity diagnostics. With SFS data SVM provided 100 % sensitivity and specificity for a several input data combinations. Among these combinations those that require minimal data inputs are identified.
T2  - Journal of Fluorescence
T1  - Support Vector Machine on Fluorescence Landscapes for Breast Cancer Diagnostics
VL  - 22
IS  - 5
SP  - 1281
EP  - 1289
DO  - 10.1007/s10895-012-1070-0
ER  - 

@article{
author = "Dramićanin, Tatjana and Lenhardt, Lea I. and Zeković, Ivana Lj. and Dramićanin, Miroslav",
year = "2012",
abstract = "Excitation-emission matrices (EEM) and total synchronous fluorescence spectra (SFS) of normal and malignant breast tissue specimens are measured in UV-VIS spectral region to serve as data inputs in development of Support Vector Machine (SVM) based breast cancer diagnostics tool. Various input data combinations are tested for classification accuracy using SVM prediction against histopathology findings to discover the best combination regarding diagnostics sensitivity and specificity. It is shown that with EEM data SVM provided 67 % sensitivity and 62 % specificity diagnostics. With SFS data SVM provided 100 % sensitivity and specificity for a several input data combinations. Among these combinations those that require minimal data inputs are identified.",
journal = "Journal of Fluorescence",
title = "Support Vector Machine on Fluorescence Landscapes for Breast Cancer Diagnostics",
volume = "22",
number = "5",
pages = "1281-1289",
doi = "10.1007/s10895-012-1070-0"
}

Dramićanin, T., Lenhardt, L. I., Zeković, I. Lj.,& Dramićanin, M.. (2012). Support Vector Machine on Fluorescence Landscapes for Breast Cancer Diagnostics. in Journal of Fluorescence, 22(5), 1281-1289.
https://doi.org/10.1007/s10895-012-1070-0

Dramićanin T, Lenhardt LI, Zeković IL, Dramićanin M. Support Vector Machine on Fluorescence Landscapes for Breast Cancer Diagnostics. in Journal of Fluorescence. 2012;22(5):1281-1289.
doi:10.1007/s10895-012-1070-0 .

Dramićanin, Tatjana, Lenhardt, Lea I., Zeković, Ivana Lj., Dramićanin, Miroslav, "Support Vector Machine on Fluorescence Landscapes for Breast Cancer Diagnostics" in Journal of Fluorescence, 22, no. 5 (2012):1281-1289,
https://doi.org/10.1007/s10895-012-1070-0 . .

TY  - JOUR
AU  - Zeković, Ivana Lj.
AU  - Lenhardt, Lea I.
AU  - Dramićanin, Tatjana
AU  - Dramićanin, Miroslav
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5027
AB  - Synchronous fluorescence spectroscopy, a technique that measures both the absorption and the emission properties of a sample in a single measurement, was used for the analysis and classification of intact cereal flours (wheat, corn, rye, buckwheat, rice, and barley). Total synchronous fluorescence spectra recorded in constant wavelength mode show clear differences in the emission spectra of different flours due to variances in intrinsic fluorophore concentrations and their microenvironments. Principal component analysis, cluster analysis, and partial least squares discriminant analysis are used to assess the ability of synchronous fluorescence measurements to differentiate and classify intact samples of different flour types. The flour specimens were obtained directly from a market in Belgrade and had different expiration dates to provide a more representative set of samples. The results of the current analysis suggest that chemometric methods applied on synchronous fluorescence data can discriminate and classify flour types and that the best results are achieved using a combination of synchronous fluorescence measurements at synchronous intervals of 7 and 20 nm. The quality of results, the high speed of measurements, and the avoidance of extensive sample preparation make synchronous fluorescence spectroscopy a promising technique for cereal research.
T2  - Food Analytical Methods
T1  - Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy
VL  - 5
IS  - 5
SP  - 1205
EP  - 1213
DO  - 10.1007/s12161-011-9359-1
ER  - 

@article{
author = "Zeković, Ivana Lj. and Lenhardt, Lea I. and Dramićanin, Tatjana and Dramićanin, Miroslav",
year = "2012",
abstract = "Synchronous fluorescence spectroscopy, a technique that measures both the absorption and the emission properties of a sample in a single measurement, was used for the analysis and classification of intact cereal flours (wheat, corn, rye, buckwheat, rice, and barley). Total synchronous fluorescence spectra recorded in constant wavelength mode show clear differences in the emission spectra of different flours due to variances in intrinsic fluorophore concentrations and their microenvironments. Principal component analysis, cluster analysis, and partial least squares discriminant analysis are used to assess the ability of synchronous fluorescence measurements to differentiate and classify intact samples of different flour types. The flour specimens were obtained directly from a market in Belgrade and had different expiration dates to provide a more representative set of samples. The results of the current analysis suggest that chemometric methods applied on synchronous fluorescence data can discriminate and classify flour types and that the best results are achieved using a combination of synchronous fluorescence measurements at synchronous intervals of 7 and 20 nm. The quality of results, the high speed of measurements, and the avoidance of extensive sample preparation make synchronous fluorescence spectroscopy a promising technique for cereal research.",
journal = "Food Analytical Methods",
title = "Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy",
volume = "5",
number = "5",
pages = "1205-1213",
doi = "10.1007/s12161-011-9359-1"
}

Zeković, I. Lj., Lenhardt, L. I., Dramićanin, T.,& Dramićanin, M.. (2012). Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy. in Food Analytical Methods, 5(5), 1205-1213.
https://doi.org/10.1007/s12161-011-9359-1

Zeković IL, Lenhardt LI, Dramićanin T, Dramićanin M. Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy. in Food Analytical Methods. 2012;5(5):1205-1213.
doi:10.1007/s12161-011-9359-1 .

Zeković, Ivana Lj., Lenhardt, Lea I., Dramićanin, Tatjana, Dramićanin, Miroslav, "Classification of Intact Cereal Flours by Front-Face Synchronous Fluorescence Spectroscopy" in Food Analytical Methods, 5, no. 5 (2012):1205-1213,
https://doi.org/10.1007/s12161-011-9359-1 . .