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Jelena Golubovi Ana Proti Mira Ze
evi Biljana Otaevi Marija Miki 《Journal of Chemometrics》2014,28(7):567-574
The study of experimental design in conjunction with artificial neural networks for optimization of isocratic ultra performance liquid chromatography method for separation of mycophenolate mofetil and its degradation products has been reported. Experimental design showed to be suitable for selection of experimental scheme, while Kennard‐Stone algorithm was used for selection of training data set. The input variables were column temperature and composition of mobile phase including percentage of acetonitrile, concentration of ammonium acetate in buffer, and its pH value. The retention factor of the most retentive component and selectivity factors were used as the dependent variables (outputs). In this way, artificial neural network has been applied as a predictable tool in solving a method optimization problem using small number of experiments. Network architecture and training parameters were optimized to the lowest root‐mean‐square error values, and the network with 5‐4‐4‐4 topology has been selected as the most predictable one. Predicted data were in good agreement with experimental data, and regression statistics confirmed good ability of trained network to predict compounds retention. The optimal chromatographic conditions included column temperature of 40°C, flow rate of 700 µl min−1, 26% of acetonitrile and 9 mM ammonium acetate in mobile phase, and buffer pH of 5.87. The chromatographic analysis has been achieved within 5.2 min. The validation of the proposed method was also performed considering selectivity, linearity, accuracy, precision, limit of detection, and limit of quantification, and the results indicated that the method fulfilled all required criteria. The method was successfully applied to the analysis of commercial dosage form. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
356.
Dušanka Milojković-Opsenica Petar Ristivojević Filip Andrić Jelena Trifković 《Chromatographia》2013,76(19-20):1239-1247
An overview of opportunities of contemporary planar chromatography in pattern recognition and fingerprint analysis is presented. The most used chemometric methods are highlighted and their main advantages and drawbacks are underlined. In addition a cross section of the application of planar chromatographic fingerprinting in food, pharmaceutical, environmental, and forensic analysis is given. 相似文献
357.
Jelena G. Stamenković Olga P. Jovanović Jovana D. Ickovski Ivan R. Palić Gordana S. Stojanović 《Natural product research》2020,34(13):1947-1950
AbstractChemical composition of the headspace volatiles and essential oils isolated from different parts of Ferulago sylvatica was determined by GC and GC/MS analyses. The results showed that headspace volatiles obtained from the aerial parts and roots were similar regarding the number of identified compounds and main components. However, essential oils obtained from different plant organs showed significant differences in chemical composition. Myrcene was the most abundant component of the inflorescences and shoots volatiles, while α-pinene make up over 50% of the root volatiles. Only three components were identified in the root essential oil with 2,3,6-trimethyl benzaldehyde (92.7%) as the main component. In the shoots sample the terpenoid fractions represented 56% of the oil, unevenly distributed between monoterpenoids and sesquiterpenoids with germacrene D (32.5%) recognized as the main constituent. On the other hand, more than 94% of the inflorescences oils were monoterpenoids with myrcene as the most abundant contributor (29.2%). 相似文献
358.
Jens Moons Francisco de Azambuja Jelena Mihailovic Karoly Kozma Katarina Smiljanic Mehran Amiri Tanja Cirkovic Velickovic May Nyman Tatjana N. Parac‐Vogt 《Angewandte Chemie (International ed. in English)》2020,59(23):9094-9101
The selective hydrolysis of proteins by non‐enzymatic catalysis is difficult to achieve, yet it is crucial for applications in biotechnology and proteomics. Herein, we report that discrete hafnium metal‐oxo cluster [Hf18O10(OH)26(SO4)13?(H2O)33] ( Hf18 ), which is centred by the same hexamer motif found in many MOFs, acts as a heterogeneous catalyst for the efficient hydrolysis of horse heart myoglobin (HHM) in low buffer concentrations. Among 154 amino acids present in the sequence of HHM, strictly selective cleavage at only 6 solvent accessible aspartate residues was observed. Mechanistic experiments suggest that the hydrolytic activity is likely derived from the actuation of HfIV Lewis acidic sites and the Brønsted acidic surface of Hf18 . X‐ray scattering and ESI‐MS revealed that Hf18 is completely insoluble in these conditions, confirming the HHM hydrolysis is caused by a heterogeneous reaction of the solid Hf18 cluster, and not from smaller, soluble Hf species that could leach into solution. 相似文献
359.
Ana Damjanovi Branka Kolundija Ivana Z. Mati Ana Krivokua Gordana Zduni Katarina avikin Radmila Jankovi Jelena Anti Stankovi Tatjana P. Stanojkovi 《Molecules (Basel, Switzerland)》2020,25(22)
Mahonia aquifolium and its secondary metabolites have been shown to have anticancer potential. We performed MTT, scratch, and colony formation assays; analyzed cell cycle phase distribution and doxorubicin uptake and retention with flow cytometry; and detected alterations in the expression of genes involved in the formation of cell–cell interactions and migration using quantitative real-time PCR following treatment of lung adenocarcinoma cells with doxorubicin, M. aquifolium extracts, or their combination. MTT assay results suggested strong synergistic effects of the combined treatments, and their application led to an increase in cell numbers in the subG1 phase of the cell cycle. Both extracts were shown to prolong doxorubicin retention time in cancer cells, while the application of doxorubicin/extract combination led to a decrease in MMP9 expression. Furthermore, cells treated with doxorubicin/extract combinations were shown to have lower migratory and colony formation potentials than untreated cells or cells treated with doxorubicin alone. The obtained results suggest that nontoxic M. aquifolium extracts can enhance the activity of doxorubicin, thus potentially allowing the application of lower doxorubicin doses in vivo, which may decrease its toxic effects in normal tissues. 相似文献
360.
Najdanović Slobodan M. Petrović Milica M. Kostić Miloš M. Mitrović Jelena Z. Bojić Danijela V. Antonijević Milan D. Bojić Aleksandar Lj. 《Research on Chemical Intermediates》2020,46(1):661-680
Research on Chemical Intermediates - A new method of synthesis was developed for the preparation of basic bismuth nitrate [Bi6O5(OH)3](NO3)5·2H2O (ECBBN). Electrochemical synthesis of the... 相似文献