Publications by authors named "O Kozlov"
The distinction of lipid isomers is gaining more attention in lipidomics due to their different biochemical properties in the organism. Herein, we aimed to develop a method for the analysis of monoacylglycerol (MG) and diacylglycerol (DG) enantiomers in biological samples using chiral supercritical fluid chromatography and mass spectrometry (SFC-MS). Amylose-based chiral columns showed a certain degree of separation of MG and DG isomers, but low selectivity for the acylglycerol classes in total lipid extracts, which could not be improved by modifier composition or other chromatographic conditions.
View Article and Find Full Text PDFObjective: Aim: To evaluate the effectiveness of PSAE for secondary prevention of VB episodes in patients with chronic liver disease (CLD) and CSPH.
Patients And Methods: Materials and Methods: One hundred twenty patients (from 2008 to 2020) were submitted of PSAE as secondary prevention treatment. The results of the treatment of 27 patients between 2008 and 2012 (first period) were compared with those of 93 patients treated with PSAE since 2013 (second period), as procedure and management protocol were modificated.
Supercritical fluid chromatography (SFC) is a rapidly expanding technique in the analysis of nonpolar to moderately polar substances and, more recently, also in the analysis of compounds with higher polarity. Herein, we demonstrate a proof of concept for the application of a commercial SFC instrument with electrospray ionization-mass spectrometry (MS) detection as a platform for the comprehensive analysis of metabolites with the full range of polarities, from nonpolar lipids up to highly polar metabolites. The developed single-platform SFC-MS lipidomic/metabolomic method is based on two consecutive injections of lipid and polar metabolite extracts from biphase methyl -butyl ether extraction using a diol column and two different gradient programs of methanol-water-ammonium formate modifier.
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- Phylogenetic inference using maximum likelihood often explores vast search spaces, with different starting trees potentially leading to a single tree topology or multiple distinct topologies depending on input data.
- Haag et al. developed a method to determine the difficulty of datasets for phylogenetic inference, showing that easier multiple sequence alignments (MSAs) tend to converge quickly to one topology, while more complex datasets present multiple optimal likelihood peaks.
- The introduction of an adaptive tree search heuristic in RAxML-NG modifies search strategies based on predicted dataset difficulty, achieving significant speedups—averaging over 10× faster—particularly for easy and difficult datasets.
The fast and selective separation method of intact monoacylglycerol (MG) and diacylglycerol (DG) isomers using chiral supercritical fluid chromatography-mass spectrometry (SFC-MS) was developed and employed to study lipase selectivity in the hydrolysis of triacylglycerols (TGs). The synthesis of 28 enantiomerically pure MG and DG isomers was performed in the first stage using the most commonly occurring fatty acids in biological samples such as palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and docosahexaenoic acids. To develop the SFC separation method, different chromatographic conditions such as column chemistry, mobile phase composition and gradient, flow rate, backpressure, and temperature were carefully assessed.
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