Journals
2019 EN
Marta Valášková · Jonáš Tokarský · Jiří Pavlovský
+2 more
Photocatalysis is increasingly becoming a center of interest due to its wide use in environmental remediation. Hematite (α-Fe 2 O 3 ) is one promising candidate for photocatalytic applications. Clay materials as vermiculite (Ver) can be used as a carrier to accommodate and stabilize photocatalysts. Two different temperatures (500 °C and 700 °C) were used for preparation of α-Fe 2 O 3 nanoparticles/vermiculite clay materials. The experimental methods used for determination of structural, optical and photocatalytic properties were X-ray fluorescence (ED-XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), N 2 adsorption method (BET), diffuse reflectance UV-Vis spectroscopy (DRS), photoluminescence spectroscopy (PL) and photocatalytic reduction of CO 2 , respectively. The data from XRD were confronted with molecular modeling of the material arrangement in the interlayer space of vermiculite structure and the possibility of anchoring the α-Fe 2 O 3 nanoparticles to the surface and edge of vermiculite. Correlations between structural, textural, optical and electrical properties and photocatalytic activity have been studied in detail. The α-Fe 2 O 3 and α-Fe 2 O 3 /Ver materials with higher specific surface areas, a smaller crystallite size and structural defects (oxygen vacancies) that a play crucial role in photocatalytic activity, were prepared at a lower calcination temperature of 500 °C.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Miroslava Filip Edelmannová · Lada Dubnová · Martin Reli
+5 more
F-La/TiO 2 photocatalysts were studied in photocatalytic decomposition water-methanol solution. The structural, textural, optical, and electronic properties of F-La/TiO 2 photocatalysts were studied by combination of X-ray powder diffraction (XRD), nitrogen physisorption, Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), Electrochemical impedance spectroscopy (EIS), and X-ray fluorescence (XPS). The production of hydrogen in the presence of 2.8F-La/TiO 2 was nearly up to 3 times higher than in the presence of pure TiO 2 . The photocatalytic performance of F-La/TiO 2 increased with increasing photocurrent response and conductivity originating from the higher amount of fluorine presented in the lattice of TiO 2 .
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Kamila Wojciechowska · Magdalena Król · Tomasz Bajda
+1 more
Desilication and dealumination techniques were used to obtain mesoporous ZSM-5 and mordenite zeolites. The study provides insight into specific structural, textural, and sorption properties of obtained materials with different Si/Al ratios. Subsequent dealumination and desilication procedures were found to be efficient methods of generating a secondary system of mesopores in mordenite and ZSM-5 crystals while preserving their microporous character. The investigated materials were evaluated in terms of their sorption properties of selected heavy metal cations (Cd 2+ , Cr 3+ , and Pb 2+ ). Particular emphasis was placed on the structural examination of the materials via infrared spectroscopy (FT-IR). Other research methods included X-ray diffraction (XRD), X-ray fluorescence (XRF), nuclear magnetic resonance (NMR) and atomic absorption spectrometry (AAS).
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Marta PrześniakWelenc · Małgorzata Nadolska · Barbara Kościelska
+1 more
Ammonium metavanadate, NH 4 VO 3 , plays an important role in the preparation of vanadium oxides and other ammonium compounds, such as NH 4 V 3 O 8 , (NH 4 ) 2 V 3 O 8 , and NH 4 V 4 O 10 , which were found to possess interesting electrochemical properties. In this work, a new route for the synthesis of NH 4 VO 3 is proposed by mixing an organic ammonium salt and V 2 O 5 in a suitable solvent. The one-step procedure is carried out at room temperature. Additionally, the need for pH control and use of oxidants necessary in known methods is eliminated. The mechanism of the NH 4 VO 3 formation is explained. It is presented that it is possible to tailor the morphology and size of the obtained NH 4 VO 3 crystals, depending on the combination of reagents. Nano- and microcrystals of NH 4 VO 3 are obtained and used as precursors in the hydrothermal synthesis of higher ammonium vanadates. It is proven that the size of the precursor particles can significantly affect the physical and chemical properties of the resulting products.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Magdalena Janus · Szymon Mądraszewski · Kamila Zając
+3 more
In this paper, studies of the mechanical properties and photocatalytic activity of new photoactive cement mortars are presented. The new building materials were obtained by the addition of 1, 3, and 5 wt % (based on the cement content) of nitrogen-modified titanium dioxide (TiO 2 /N) to the cement matrix. Photocatalytic active cement mortars were characterized by measuring the flexural and the compressive strength, the hydration heat, the zeta potential of the fresh state, and the initial and final setting time. Their photocatalytic activity was tested during NOx decomposition. The studies showed that TiO 2 /N gives the photoactivity of cement mortars during air purification with an additional positive effect on the mechanical properties of the hardened mortars. The addition of TiO 2 /N into the cement shortened the initial and final setting time, which was distinctly observed using 5 wt % of the photocatalyst in the cement matrix.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Inga Dziembowska · Małgorzata Wójcik · Iga Hołyńska-Iwan
+3 more
Background and Objectives: Top-level sports performance places heavy physical and psychological demands on elite-level athletes, which can be a source of increased levels of stress. Therefore, high-level volleyball players may present altered cardiovascular and endocrinological stress response during stressful events. Although many previous studies have examined the response to stress on athletes, most of them regarded only males, while the impact of the female menstrual cycle has rarely been taken into account. We aimed to study psychophysiological response to anticipatory stressor through analysis of heart rate, self-reported anxiety level, and salivary cortisol in healthy young female athletes by minimalizing the effect of confounders. Materials and Methods: A total of 55 females (25 members of the best league for female volleyball players in Poland and 30 sedentary-lifestyle control subjects) in the follicular phase of their menstrual cycle were exposed to mental arithmetic tasks as an experimental imitation of the stressor. Volleyball players were significantly taller than sedentary individuals (177.1 ± 3.4 cm vs. 173.3 ± 3.4 cm, respectively, p = 0.034), but did not differ in weight (73.6 ± 5.2 kg vs. 70 ± 4.23 kg, respectively, p = 0.081), body mass index (BMI) (23.5 ± 1.13 vs. 24.1 ± 1.45, respectively, p = 0.060), and age (22 ± 1.11 vs. 23 ± 1.14 years, respectively, p = 0.2). Their stress responses were assessed through self-reported anxiety levels and physiological measurements of salivary cortisol concentrations and heart rate (HR). Results: For HR, significant effects of time (F (2,120) = 21.34, p < 0.001, η 2 = 0.26) were found, but not for training status (F (1,60) = 2.69, p = 0.106, η 2 = 0.04). For cortisol levels, the analysis showed the main effects of time (F (3,180) = 11.73, p < 0.001, η 2 = 0.16) and training status (F (1,60) = 4.69, p = 0.034, η 2 = 0.07) and a significant interaction between training status and time (F (3,180) = 3.07, p = 0.029, η 2 = 0.05). Post-hoc analyses showed higher cortisol concentrations among volleyball players following the math task (all p < 0.001), as well as higher cortisol concentrations in S2, S3, and S4 compared to S1 in volleyball players (all p < 0.001). We observed also a significant increase in state anxiety in both groups (all p < 0.001), but no differences in state anxiety levels between groups. Conclusion: Female volleyball players may not differ in subjective graduation of stressors; however, exposure to training-based stressors seems to promote cortisol response to the anticipated stressor.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Hakime Hülya Orak · Magdalena Karamać · Ryszard Amarowicz
+2 more
The phenolic compound contents and antioxidant activities of the leaf extracts of nine olive genotypes were determined, and the obtained data were analysed using chemometric techniques. In the crude extracts, 12 compounds belonging to the secoiridoids, phenylethanoids, and flavonoids were identified. Oleuropein was the primary component for all genotypes, exhibiting a content of 21.0 to 98.0 mg/g extract. Hydroxytyrosol, verbascoside, luteolin 7- O -glucoside, and luteolin 4'- O -glucoside were also present in noticeable quantities. Genotypes differed to the greatest extent in the content of verbascoside (0.45⁻21.07 mg/g extract). The content of hydroxytyrosol ranged from 1.33 to 4.03 mg/g extract, and the aforementioned luteolin glucosides were present at 1.58⁻8.67 mg/g extract. The total phenolic content (TPC), DPPH • and ABTS •+ scavenging activities, ferric reducing antioxidant power (FRAP), and ability to inhibit the oxidation of -carotene-linoleic acid emulsion also varied significantly among genotypes. A hierarchical cluster analysis enabled the division of genotypes into three clusters with similarity above 60% in each group. GGE biplot analysis showed olive genotypes variability with respect to phenolic compound contents and antioxidant activities. Significant correlations among TPC, FRAP, the values of both radical scavenging assays, and the content of oleuropein were found. The contents of 7- O -glucoside and 4'- O -glucoside correlated with TPC, TEAC, FRAP, and the results of the emulsion oxidation assay.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Anna Oniszczuk · Kamila KasprzakDrozd · Agnieszka Wójtowicz
+2 more
Buckwheat is a generous source of phenolic compounds, vitamins and essential amino acids. This paper discusses the procedure of obtaining innovative gluten-free, precooked pastas from roasted buckwheat grains flour, a fertile source of natural antioxidants, among them, phenolic acids. The authors also determined the effect of the extruder screw speed and the level of moisture content in the raw material on the quantity of free phenolic acids. The qualitative and quantitative analysis of phenolic acids in pasta was carried out using high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The chromatographic method was validated. For extracts with the highest total content of free phenolic acids and unprocessed flour from roasted buckwheat grain, the TLC-DPPH test was also performed to determine the antioxidant properties of the tested pasta. The level of moisture in the raw material had an impact on the content of phenolic acids. All pastas made from buckwheat flour moistened up to 32% exhibited a higher total content of free phenolic acids than other mixes moistened to 30 and 34% of water.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Anna Klimek-Turek · Kamila Jaglińska · Magdalena Imbierowicz
+1 more
The new prototype device is applied to the Solvent Front Position Extraction (SFPE) sample preparation procedure. The mobile phase is deposited onto the chromatographic plate adsorbent layer by the pipette, which is moved, according to programmed movement path, by a 3D printer mechanism. The application of the prototype device to SFPE procedure leads to the increased repeatability of the results and significant reduction of the analysis time in comparison to the classical procedure of chromatogram development. Additionally, the new equipment allows use procedures that are not possible to run using the classic chromatogram development. In this paper, the results of manual and semi-automatic sample preparation with SFPE are compared and the possible application of this prototype device is discussed.
Multidisciplinary Digital Publishing Institute
Journals
2019 EN
Jana Kubíčková · Katarína Elefantová · Lucia Pavlíková
+10 more
We describe the screening of a set of cryptopleurine derivatives, namely thienoquinolizidine derivatives and (epi-)benzo analogs with bioactive phenanthroquinolizidine alkaloids that induce cytotoxic effects in the mouse lymphocytic leukemia cell line L1210. We used three variants of L1210 cells: i) parental cells (S) negative for P-glycoprotein (P-gp) expression; ii) P-glycoprotein positive cells (R), obtained by selection with vincristine; iii) P-glycoprotein positive cells (T), obtained by stable transfection with a human gene encoding P-glycoprotein. We identified the most effective derivative 11 with a median lethal concentration of ≈13 μM in all three L1210 cell variants. The analysis of the apoptosis/necrosis induced by derivative 11 revealed that cell death was the result of apoptosis with late apoptosis characteristics. Derivative 11 did not induce a strong alteration in the proportion of cells in the G 1 , S or G 2 /M phase of the cell cycle, but a strong increase in the number of S, R and T cells in the subG 1 phase was detected. These findings indicated that we identified the most effective inducer of cell death, derivative 11 , and this derivative effectively induced cell death in S, R and T cells at similar inhibitory concentrations independent of P-gp expression.
Multidisciplinary Digital Publishing Institute