Studies on 16-Membered Azothia- and Azoxythiacrown Ethers as Ion Carriers in Ion Selective Membranes

16-Membered azothia- and azoxythiacrown ethers have been studied as ion carriers in ion-selective membranes. Their selectivities towards alkali, alkaline earth, transition and heavy metal cations were evaluated. The complex formation constants for these compounds with chosen cations have been determined using segmented sandwich membranes method.     

Spectroscopic and atomic force microscopy investigations of hybrid materials composed of fullerenes and 3-aminopropyltrimethoxysilane

Fullerene based materials may open a new horizon in many fields of science. In this study we fabricated thin films of the hybrid materials formed as a result of interactions between C₆₀ fullerenes and 3-aminopropyltrimethoxysilane (APTMS). The deposition technique was a combination of spin-coating and evaporation methods. Interactions within the films were investigated by means of X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy (NEXAFS). Surface morphology was measured by atomic force microscopy (AFM). We found that there are strong chemical reactions between the nucleophilic nitrogen atoms from APTMS and electrophilic fullerene molecules. Results of NEXAFS investigations suggest that due to direct interactions between APTMS and C₆₀ the electronic structure of the fullerene molecules changes while at the same time AFM proved that the C₆₀ molecule diameter is not altered.     

Detection of butter adulteration with water using differential scanning calorimetry

The study evaluated the applicability of differential scanning calorimetry (DSC) for the detection of water content in butter. High correlation coefficients were found between the water content and the enthalpies of the ice melting/water crystallization. The correlation equations were adopted to calculate the water content for seven tested kinds of butter, and the results were compared with the values, obtained by using the reference method. The difference between the water content determined by the reference method and by DSC ranged between 0.2 and 2.6% for the measured enthalpy of ice melting, and between 1 and 5.6% for the enthalpy of water crystallization. In relation to the data obtained, it can be concluded that the parameter of ice melting enthalpy can be used in the identification of adulterations or confirmation of butter authenticity.     

The Computer-Aided Design,Synthesis, and Activity Prediction of New Leucine Aminopeptidase Inhibitors

The design, stereo-, and enantioselective synthesis and activity prediction of aminophosphonic acids as new leucine aminopeptidase inhibitors will be discussed.     

Quinazoline Antifolate Thymidylate Synthase Inhibitors: Replacement of Glutamic Acid by Aminophosphonic Acids

The synthesis of six analogues of the potent thymidylate synthase (TS) inhibitor N -[4-[ N -[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinoyl)-methyl]- N -prop-2-ynylamino]benzoyl]- L -glutamic acid 2 is described in which the glutamic acid residue has been replaced by DL -aminophosphonic acids. New antifolates were tested as inhibitors of TS isolated from mouse L1210 leukemic cells as well as inhibitors of growth mouse leukemic L5178Y cells. In general these modifications result in compounds that are considerably less potent than 2 as TS inhibitors with K i 's 0.17-1.10 w M. Very poor solubility in water limited their proper assay of growth cells inhibition.     

Usefulness of chaotropic salt additive in RP‐HPLC of organic nonionized compounds

New synthesized 1,4‐disubstituted thiosemicarbazide derivatives were analyzed in the RP system, modified with the addition of salts; chaotropic (sodium hexafluorophosphate – Na PF₆), cosmotropic (sodium phosphate – NaH₂PO₄), and neutral (NaCl) on Zorbax XDB C18 column. The effect of the eluent composition on the analytes retention (k), system efficiency (N), peak symmetry (A_s), and LOD values were all examined and compared to unmodified organic‐aqueous mobile phase system. It was established that eluent modified with chaotropic salts addition was also the most advantageous according to other peak parameters such as the theoretical plates numbers and asymmetry factors. The lower LOD values were achieved in comparison to unmodified organic‐aqueous eluent system. Compatibility of lipophilicity parameters calculated by the use of computer software with experimental ones measured by RP‐HPLC was also the best for chaotropic modified mobile phase. To explain the observed phenomena, molecular modeling was performed for chosen representative compound in different environment representing examined mobile phase composition.     

Adsorption of tert-butanol at the electrode from concentrated NaClO4 solutions

The parameters of the double layer for tert-butanol adsorption determined in the supporting electrolytes: 2 mol dm^?3, 3 mol dm^?3 and 4 mol dm^?3 NaClO₄, show an increase of tert-butanol adsorption on the mercury electrode together with the increase of NaClO₄ concentration. The adsorption of tert-butanol on the electrode takes place via the ?CH₃ group which is shown by the changes in the values of zero charge potentials, E _z. On the basis of the analysis of the changes of relative surface excess values, Γ′, and the parameters determining the maximum adsorption, the process of adsorption in the discussed systems can be recognized as a physical process. Besides, it can be said that a major drawback in the process of adsorption of the organic substance on the electrode is to remove water from the electrode surface.     

Application of hot platinum microelectrodes for determination of flavonoids in flow injection analysis and capillary electrophoresis

The determination of quercetin and rutin by flow injection analysis (FIA) and capillary electrophoresis (CE) using electrochemical detection was described. These flavonoids were determined at normal (unheated) and hot platinum microelectrodes using cyclic voltammetry. When quercetin or rutin is reaching the platinum electrode, a change of the current in the region of the platinum oxide formation is observed. Integration of the current changes in this in this region creates analytical signals in the form of peaks. An increase of temperature to about 76 ?C in a small zone adjacent to the microelectrode causes an increase of the analytical signal by more than 6 times under FIA conditions. This method enables the use of hot microelectrodes as detectors in HPLC or CE. In CE the improvement of the analytical signal at hot microelectrodes is smaller than in FIA and increase only 1.3–3.4 times. Heated microelectrodes were used for analysis of the flavonoids in natural samples of the plant (extract of sea buckthorn) and a pharmaceutical preparation (Cerutin).     

Role of Gut Microbiota,Probiotics and Prebiotics in the Cardiovascular Diseases

In recent years, there has been a growing interest in identifying and applying new, naturally occurring molecules that promote health. Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer health benefits on the host”. Quite a few fermented products serve as the source of probiotic strains, with many factors influencing the effectiveness of probiotics, including interactions of probiotic bacteria with the host’s microbiome. Prebiotics contain no microorganisms, only substances which stimulate their growth. Prebiotics can be obtained from various sources, including breast milk, soybeans, and raw oats, however, the most popular prebiotics are the oligosaccharides contained in plants. Recent research increasingly claims that probiotics and prebiotics alleviate many disorders related to the immune system, cancer metastasis, type 2 diabetes, and obesity. However, little is known about the role of these supplements as important dietary components in preventing or treating cardiovascular disease. Still, some reports and clinical studies were conducted, offering new ways of treatment. Therefore, the aim of this review is to discuss the roles of gut microbiota, probiotics, and prebiotics interventions in the prevention and treatment of cardiovascular disease.