171 research outputs found
Quantitative structure-retention relationship study of arylpiperazines by liquid chromatography and multivariate chemometric methods
Cilj ove disertacije bilo je sistematsko prouÄavanje hromatografskog ponaÅ”anja
serije novosintetisanih arilpiperazina u uslovima planarne hromatografije, procena
retencionih podataka na osnovu multivarijantnih statistiÄkih metoda i utvrÄivanje veze
izmeÄu retencionih karakteristika i fiziÄko-hemijskih parametara ispitivanih molekula.
RazliÄiti reverzno-fazni hromatografski sistemi uspeÅ”no su primenjeni za
razdvajanje ispitivanih arilpiperazina. Definisane su meÄumolekulske interakcije koje
upravljaju retencionim ponaŔanjem ispitivanih supstanci. To su pre svega hidrofobne,
elektrostatiÄke i interakcije koje ukljuÄuju graÄenje vodoniÄnih veza. PonaÅ”anje
arilpiperazina u primenjenim hromatografskim uslovima u saglasnosti je sa njihovim
strukturnim svojstvima, kao i sa interakcijama za koje je utvrÄeno da se uspostavljaju
kada se ligand koji pokazuje afinitet prema dopaminskim D2 i serotoninskim 5-HT1A
receptorima približi aktivnom centru receptora.
Lipofilnost ispitivanih arilpiperazina odreÄena je pomoÄu Äetiri hromatografska
deskriptora, RM
0, b, C0 i PC1. Na osnovu statistiÄkih parametara linearne zavisnosti
pomenutih deskriptora i izraÄunatih logP vrednosti, utvrÄeno je da varijabla koja
direktno opisuje raspodelu supstanci izmeÄu stacionarne i mobilne faze, kao Å”to je
parameter RM
0, pouzdanije odreÄuje lipofilnost ispitivanih arilpiperazina od parametra
koji je proporcionalan hidrofobnoj povrÅ”ini molekula (b) ili interpolisane veliÄine koja
obuhvata sve hromatografske podatke jednog sistema (PC1).
Analiza glavnih komponenata i klasterska analiza kao i viŔestruka linearna
regresija, regresija metodom delimiÄnih-najmanjih kvadrata i regresija glavnih
komponenata primenjene su za identifikaciju molekulskih deskriptora koji na najbolji
naÄin opisuju ponaÅ”anje ispitivanih jedinjenja u hromatografskom sistemu, kao i za
kvantifikaciju njihovog uticaja, a u cilju dobijanja matematiÄkih modela koji bi mogli
da predvide hromatografsko ponaŔanje, odnosno lipofilnost novih srodnih molekula.
StatistiÄki parametri potvrÄuju da su predloženi modeli statistiÄki znaÄajni i uporedivi.
Molekulski deskriptori ukljuÄeni u konaÄne modele su sliÄne prirode i njihov uticaj je
približno jednak. PotvrÄeno je da je hromatografsko ponaÅ”anje molekula odreÄeno
dvema komponentama, veliÄinom molekula i sposobnoÅ”Äu graÄenja vodoniÄnih veza.
Usled veÄeg uticaja parametara rastvorljivosti na RM
0 vrednosti, pretpostavljeno je da je
u posmatranom hromatografskom sistemu particija dominantni mehanizam razdvajanja
u odnosu na adsorpciju. Prediktivna svojstva dobijenih modela potvrÄuju moguÄnost
njihovog koriÅ”Äenja za predviÄanje lipofilnosti novih, strukturno sliÄnih jedinjenja, kao i
za razumevanje njihovog hromatografskog ponaŔanja.The main goal of this PhD thesis was a systematic study of the retention of the
newly synthesized arylpiperazines in planar chromatographic conditions, evaluation of
the retention data by multivariate statistical methods and determination of the possible
relationship between the retention characteristics and the physicochemical parameters of
the investigated arylpiperazines.
Different reversed-phase chromatographic systems are successfully applied for the
separation of the investigated arylpiperazines. Hydrophobic, electrostatic and hydrogen
bond interactions were defined as the most important molecular interactions govern the
retention process. The results obtained are in accordance with the structural properties
of the investigated compounds and moreover with the interactions established for their
binding affinity at the dopamine D2 and serotonin 5-HT1A receptors.
Four chromatographic descriptors, RM
0, b, C0 i PC1 are used for assessing the
lipophilicity of unknown solutes. These parameters were compared with calculated logP
values, and statistical quality of these dependences shows that variables describing
directly solute partitioning between stationary and mobile phase, such as RM
0, are more
suitable for lipophilicity estimation than parameters proportional to the molecular
hydrophobic surface area (b), or interpolated quantity which combines all
chromatographic data in one single feature (PC1).
Principal component analysis and cluster analysis followed by multiple linear
regression, partial least square regression and principal component regression, were
performed to identify the molecular descriptors that best describe the chromatographic
behavior of the investigated compounds, and to quantify their influences, in order to
create a model that could be able to predict chromatographic behavior or lipophilicity of
a newly synthesized molecules. The statistical parameters revealed that the models are
statistically significant and their statistical results are comparable. The descriptors
included in the final models of these three methods are of similar nature and
significance. All models confirm the importance of the size of the molecule and
hydrogen bonding interactions in assessment of their chromatographic behavior.
According to larger influence of the solubility parameters on RM
0 values, it was
concluded that partition was the dominant separation mechanism in studied
chromatographic systems. Predictive ability of the obtained models and equations based
on the physically meaningful parameters allows an estimation of lipophilicity for similar
compounds and understanding of their chromatographic behavior
Supplementary data for the article: StefanoviÄ, V.; TrifkoviÄ, J.; MutiÄ, J.; TeÅ”iÄ, Ž. Metal Accumulation Capacity of Parasol Mushroom (Macrolepiota Procera) from Rasina Region (Serbia). Environ. Sci. Pollut. Res. 2016, 23 (13), 13178ā13190. https://doi.org/10.1007/s11356-016-6486-7
Supplementary material for: [https://doi.org/10.1007/s11356-016-6486-7]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2271
Supplementary material for the article: StefanoviÄ, V.; TrifkoviÄ, J.; DjurdjiÄ, S.; VukojeviÄ, V.; TeÅ”iÄ, Ž.; MutiÄ, J. Study of Silver, Selenium and Arsenic Concentration in Wild Edible Mushroom Macrolepiota Procera, Health Benefit and Risk. Environmental Science and Pollution Research 2016, 23 (21), 22084ā22098. https://doi.org/10.1007/s11356-016-7450-2
Supplementary material for: [https://doi.org/10.1007/s11356-016-7450-2]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2348
Impact of Vial Bubble on the Accuracy of Positions in the GNSS-RTK Mode
The use of the GNSS devices in the RTK mode involves taking a vertical position using a circular spirit vial bubble located on the rod. Since the market of geodetic instruments, accessories and software is growing, the authors of this paper performed measurements with the GNSS devices in the RTK mode to determine and demonstrate the impact of the position of the central vial bubble (level) on coordinate accuracy. Measurements were performed on the same rod in the RTK permanent stations network. Instruments of different manufacturers and generations were used in the experiment. Newer generations of the GNSS devices are equipped with special sensors for measuring the inclination of the receiver and eliminating this error. Devices that do not have a sensor give measuring coordinates that are loaded with error. The error is random and cannot be measured. The subject of the analysis of this paper is the magnitude and impact of the error caused by the non-verticality of the rod on which the GNSS-RTK antenna is mounted. The authors experimentally determined that the bubble of the central level has the influence on the accuracy of the position, made conclusions and recommendations for reducing or eliminating the error of non-verticality of the pole
Effects and Profitability of Land Consolidation Projects: Case Study ā the Republic of Serbia
An analysis of profitability and effects of land consolidation (LC) projects has been made in this paper. The measurable effects of land consolidation resulting from land consolidation goals such as: increase of average area of parcel, decrease of average number of parcels per participant as well as the change in the area of road and canal networks after the land consolidation projects were considered. Profitability was analysed from the aspect of return on investments and net present value of investment in land consolidation. Materials and methods for this study encompass a representative sample from Vojvodina, a part of the Republic of Serbia which is flatland and predominately orientated to agricultural production. The study results indicate that the effects of land consolidation are good and that land consolidation projects are highly profitable
Supplementary data for the article: StefanoviÄ, V.; TrifkoviÄ, J.; MutiÄ, J.; TeÅ”iÄ, Ž. Metal Accumulation Capacity of Parasol Mushroom (Macrolepiota Procera) from Rasina Region (Serbia). Environ. Sci. Pollut. Res. 2016, 23 (13), 13178ā13190. https://doi.org/10.1007/s11356-016-6486-7
Supplementary material for: [https://doi.org/10.1007/s11356-016-6486-7]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2271
Supplementary data for article: ÄurÄiÄ, S. Z.; SredojeviÄ, M.; TrifkoviÄ, J.; VukojeviÄ, V.; NatiÄ, M.; TeÅ”iÄ, Ž. L.; MutiÄ, J. Elemental Composition as a Tool for the Assessment of Type, Seasonal Variability, and Geographical Origin of Wine and Its Contribution to Daily Elemental Intake. RSC Advances 2017, 7 (4), 2151ā2162. https://doi.org/10.1039/c6ra25105f
Supplementary material for: [https://doi.org/10.1039/c6ra25105f]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2397
Supplementary data for the article: StojsavljeviÄ, A.; TrifkoviÄ, J.; RasiÄ-MilutinoviÄ, Z.; JovanoviÄ, D.; BogdanoviÄ, G.; MutiÄ, J.; ManojloviÄ, D. Determination of Toxic and Essential Trace Elements in Serum of Healthy and Hypothyroid Respondents by ICP-MS: A Chemometric Approach for Discrimination of Hypothyroidism. Journal of Trace Elements in Medicine and Biology 2018, 48, 134ā140. https://doi.org/10.1016/j.jtemb.2018.03.020
Supplementary material for: [https://doi.org/10.1016/j.jtemb.2018.03.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2181]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3074
Elemental composition as a tool for the assessment of type, seasonal variability, and geographical origin of wine and its contribution to daily elemental intake
The elemental profiles of 63 red and white wine samples from four different regions in Serbia were investigated. Twenty-one elements were analysed (Ca, Mg, Na, K, Fe, Mn, Cu, Zn, Co, Se, Cr, V, Ni, Cd, As, Al, Sb, Pb, Ba, Rb, and Be) by inductively coupled plasma quadrupole mass spectrometry (ICP-Q-MS) and inductively coupled plasma with optical emission spectrometry (ICP-OES). A pattern recognition method was applied in order to classify and differentiate type, seasonal variability, and geographical origin of the wine. Dietary mineral intake for elements was calculated in order to assess their contribution to daily intake. The most important descriptors for discrimination among red and white wine samples were Be, Al, Rb, Mg, K, Cu, Mn, and Na, in descending order. The variables Cd, Pb, As, Sb, V, Na, K, and Zn have the highest influence on vintage-to-vintage classification of red wines. Furthermore, the model revealed the existence of three groups of descriptors for different regions of production. All obtained statistical models confirmed that data from the elemental content of wine samples could be used for accurate prediction of wine type, seasonal variability, and regional origin.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2979
Supplementary material for the article: MesaroviÄ, J.; TrifkoviÄ, J.; Tosti, T.; FotiriÄ AkÅ”iÄ, M.; MilatoviÄ, D.; LiÄina, V.; MilojkoviÄ-Opsenica, D. Relationship between Ripening Time and Sugar Content of Apricot (Prunus Armeniaca L.) Kernels. Acta Physiologiae Plantarum 2018, 40 (8). https://doi.org/10.1007/s11738-018-2731-7
Supplementary material for: [https://doi.org/10.1007/s11738-018-2731-7]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2193
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