<abstract xmlns="http://www.w3.org/1999/xhtml">A systematic study of (7,8-dimethylated) alloxazine, isoalloxazine, and their derivatives with substituted N(1) and N(10) positions was conducted using the density functional theory. The main aim of this work was the direct investigation of substituent effect on the molecular structure. Furthermore, HOMED aromaticity indices were calculated to describe the scope of the geometry changes. Frontier molecular orbitals of reference alloxazine, isoalloxazine and lumichrome derivatives were discussed by means of changes in their shape and energy levels. Photophysical properties were analyzed by determination of optical transition energies using the TD-DFT method. Obtained results were compared with previously published experimental data.</abstract>

Theoretical modeling of optical spectra of N(1) and N(10) substituted lumichrome derivatives

<abstract xmlns="http://www.w3.org/1999/xhtml">Novel technologies for organic pollutants degradation have been studied to cope with extensive water pollution. In this work, the use of ultraviolet degradation and potassium ferrate as possible oxidation tools for toluene, a widely used industrial chemical, degradation is proposed. In the experiment with ultraviolet irradiation, a low-pressure mercury lamp was used to generate a single line electromagnetic radiation with the wavelength of 254 nm. Maximal degradation efficiency achieved after 55 minutes of irradiation was 67.1 %. In the experiments with potassium ferrate, the highest degradation efficiency was 71.2 % at the concentration of 10 mg/L of ferrate (VI) anion.</abstract>

Toluene oxidation: UV irradiation vs. ferrates

<abstract xmlns="http://www.w3.org/1999/xhtml">The ability of <italic>Trichoderma</italic> strains isolated from lignite and of Earth surface-derived strains to attack (solubilise) lignite, peat and wood was compared using glutamate as a carbon source. The results showed that lignite-derived microorganisms solubilise lignite to similar extent as <italic>Trichoderma</italic> strains isolated from the Earth surface. Solubilisation processes involve the action of enzymes and alkaline pH. The solubilisation of lignite was accompanied by a small increase of conidia-bound laccase, whereas that of peat was accompanied by (secretion) activity of cellulase, laminarinase, laccase, and lignin-peroxidase-like enzyme. In addition, data were obtained which show that bacteria contained in the lignite are able of lignite solubilisation and utilisation.</abstract>

Degradation of low-rank coal excavated from coal-mine Záhorie by filamentous fungi

<abstract xmlns="http://www.w3.org/1999/xhtml">Antibiotic, soothing and healing properties of panthenol are exploited in various pharmaceutical and cosmetic products. Only D-panthenol is biologically active while its L-form might counteract the biological effectiveness of the D-enantiomer. Hydrating and moisturizing effects are exhibited by both enantiomers. Therefore, it is necessary to develop a rapid and cheap method for the determination of panthenol enantiomeric excess in pharmaceutical preparations. In this study, <italic>b</italic>-cyclodextrin was used as a chiral selector for the recognition of panthenol enantiomers. Inclusion complexes formed by <italic>b</italic>-cyclodextrin and the analyte showed small differences in NIR and UV/VIS spectra compared by chemometric assessment. Based on the figure of merit and model characteristics, PLS calibration model in the selected range of NIR spectra is preferred. UV/VIS spectrometry has the disadvantage of complicated sample preparation compared to NIR spectrometry. Results reached by both proposed methods were in good agreement. Statistical investigation of the results (by Student <italic>t</italic>-test and Fisher <italic>F</italic>-test) confirmed that the proposed methods are comparable and applicable to chiral analysis of panthenol pharmaceutical preparations.</abstract>

Spectro-chemometric determination of panthenol enantiomeric excess in pharmaceutical products

<abstract xmlns="http://www.w3.org/1999/xhtml">This work aimed to determine the effect of packing density on the sublimation rate in a laboratory freeze dryer. Total amount of sublimed water was determined by gravimetric method while a total of seven experiments were performed under the same conditions (pressure, temperature, and drying time), at different configuration of the vials. The experiments confirmed that the higher the packing density, the lower the drying rate, and vice versa, the lower the packing density, the higher the drying rate. The effect of vials packing density was confirmed by experiments using a plastic rack, while the vials were separated and thus the packing density was lower. In this case, the drying rate was more homogeneous, which contributes to the higher quality of the final product.</abstract>

Impact of packing density on primary drying rate

<abstract xmlns="http://www.w3.org/1999/xhtml">Dimethyl sulfoxide (DMSO) is an aprotic organic solvent widely used in laboratory practice due to its ability to dissolve both polar and nonpolar compounds. However, DMSO is also commonly known as a strongly coordinating solvent, especially towards transition metal containing complexes. In this study, estimation of the coordination ability of DMSO towards the Cu(II) ion was attempted, employing a model system composed of 3′,4′-dihydroxyflavone-Cu(II) complex in the presence of explicit DMSO molecules, using the density functional theory (DFT). Nature of the Cu-DMSO chemical interaction (i.e. Cu-O bonding) was studied within the framework of quantum theory of atoms in molecules (QTAIM). Impact of DMSO coordination on the charge and spin distribution at Cu(II) ion was inspected using Mulliken population and QTAIM analysis.</abstract>

Dimethyl sulfoxide as a strongly coordinating solvent: 3′,4′-dihydroxyflavone-Cu(II)-DMSO system case study

<abstract xmlns="http://www.w3.org/1999/xhtml">Increasing concentration of antibiotics in environment and their subinhibitory concentrations in wastewater may result in increased antibiotic resistance of present bacteria. Therefore, this study was aimed to analyze the efficiency of coagulase-positive staphylococci and <italic>Staphylococcus aureus</italic> inhibition in wastewater by electrochemical methods and addition of ferrates. Advanced electrochemical oxidation by boron doped diamond electrodes in anode; cathode and anode-cathode connection were used for wastewater disinfection. Results showed that the most effective connection was the anodic one, as complete inhibition of coagulase-positive staphylococci as well as of <italic>S. aureus</italic> was observed after 40 min. Energy consumption was 3.69 kWh/m3 for effluent wastewater disinfection. The second studied method of wastewater disinfection was the application of powdered ferrates. Addition of 100 mg of ferrates resulted in the inhibition of 84—96 % of coagulase-positive staphylococci and 97—99 % of <italic>S. aureus</italic> in influent water, while the inhibition of coagulase-positive staphylococci and <italic>S. aureus</italic> was 61—83 % and 83—86 %, respectively, in effluent wastewater.</abstract>

Department of Nutrition and Food Quality Assessment, Faculty of Chemical and Food Technology

Inhibition of staphylococci and <italic>S. aureus</italic> in wastewater by ferrates and electrochemical methods

<abstract xmlns="http://www.w3.org/1999/xhtml">Elevated cholesterol intake can induce the development of cardiovascular diseases in man, especially with long term animal origin foods consumption. Therefore, this work deals with the possibility of cholesterol content decrease in milk applying β-cyclodextrin crosslinked with tartaric acid (βCDcTA) as a removal agent. Evaluation of statistic data on food consumption in the Slovak Republic in 2018 aimed at total cholesterol daily intake and effects of “milky” cholesterol content decrease on total cholesterol balance. During the experiments, various amounts of βCDcTA addition to milk were studied resulting in optimal 5 % addition resulting in the cholesterol content decrease by 85.4 % in comparison to original cholesterol content. For monitoring purposes, an HPLC method analysing cholesterol content in saponified milk was employed. The food consumption data analysis showed that total per capita daily cholesterol intake was 369.8 mg, from which 86 mg was assigned to the cholesterol contained in milk and dairy products while the application of cholesterol removal procedure could decrease the total per capita daily cholesterol intake to 296.3 mg (“milky” cholesterol amount equal to 12.6 mg), which in below the recommended value of 300 mg daily intake still valid in the Slovak Republic. This approach might prove as a meaningful step to weaken health problems associated with high long term intake of cholesterol contained in foods of animal origin.</abstract>

Decrease of cholesterol content in milk by sorption onto β-cyclodextrin crosslinked with tartaric acid; considerations and implications

AHEAD OF PRINT

Volume 17 (2024): Issue 1 (January 2024)

Volume 16 (2023): Issue 1 (January 2023)

Volume 15 (2022): Issue 1 (January 2022)

Volume 14 (2021): Issue 1 (January 2021)

Volume 13 (2020): Issue 2 (October 2020)

Volume 13 (2020): Issue 1 (April 2020)

Volume 12 (2019): Issue 2 (October 2019)

Volume 12 (2019): Issue 1 (April 2019)

Volume 11 (2018): Issue 2 (October 2018)

Volume 11 (2018): Issue 1 (April 2018)

Volume 10 (2017): Issue 2 (December 2017)

Volume 10 (2017): Issue 1 (April 2017)

Volume 9 (2016): Issue 2 (October 2016)

Volume 9 (2016): Issue 1 (April 2016)

Volume 8 (2015): Issue 2 (October 2015)

Volume 8 (2015): Issue 1 (April 2015)

Volume 7 (2014): Issue 2 (October 2014)

Volume 7 (2014): Issue 1 (April 2014)

Volume 6 (2013): Issue 2 (October 2013)

Volume 6 (2013): Issue 1 (April 2013)

Volume 5 (2012): Issue 2 (November 2012)

Volume 5 (2012): Issue 1 (April 2012)

Acta Chimica Slovaca

Acta Chimica Slovaca publish papers on fundamental and applied aspects of chemistry, biochemistry, chemical technology, chemical engineering and process control, biotechnology and food technology.   Why subscribe and read   new scientific information from all branches of chemistry   Why submit   fast peer review process and editing   Rejection Rate   35% from submitted articles   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 