Crown ethers are unique compounds with exceptional ion binding properties. We investigate the 18-crown-6 ether molecule binding selectivity for a set of alkali ions (K+, Rb+, Cs+). We employ ...combination of umbrella sampling technique with the weighted histogram analysis method to derive free energies of ion-ether association. The obtained results are in a good agreement with experimental values available and represent the ion selectivity feature of the 18-crown-6 ether.
•The chemical profile of mango at four maturation stages was determined using ESI-MS.•Primary and secondary metabolites were identified at the third maturation stage.•The third stage of maturation is ...the best stage for the harvest and consumption.•The potential cancer chemoprevention of the secondary metabolites was evaluated.
Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(−)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention.
The article considers mentoring as a resource for the formation of interest in physical culture through the organization of non-standard classes in the extended day mode, taking into account the ...interests of younger schoolchildren. A survey was conducted to determine the interests of younger students in physical education. It was revealed that younger students are interested in: football, gymnastics, outdoor activities, musical rhythmic and outdoor games, the opportunity to study individually at their own pace and rhythm, with a choice of tasks. The activity of student mentors is described, taking into account the identified interests in physical culture: in classes in the extended day group, mobile and sports games with alternating computer games are implemented; dance and musical rhythmic movements using the Just Dance prefix; individual cards with variable tasks. Mentoring is defined as a resource for interest formation, implemented through relationships in the educational process with the transfer of experience and knowledge, allowing to individualize the process of education and upbringing. The conducted research revealed an increase in the interest of younger schoolchildren in physical education, which manifested itself in increased attendance and activity. Method and methodology of the work: The research uses theoretical and empirical methods. Analysis of the literature on the research problem, pedagogical experiment. The survey was conducted among students in grades 2-4 of a general education institution. It allowed us to identify interests in physical education. And to form a program for the activities of student mentors in the experimental group. At the final stage of the experiment, the expert assessment of the physical education teacher was used. Results: The study shows that the activity of student mentors contributes to an increase in interest in physical culture in the implementation of non-standard classes and communication in an extended day group. Which manifests itself in an increase in attendance and activity of younger students. Therefore, mentoring can be a resource for developing younger students’ interest in physical education.
A comparative assessment of the accuracy of determining the density and viscosity has been carried out for diisopropyl ether using the method of classical molecular dynamics using three potentials. ...The accuracy of determining the viscosity coefficients when using equilibrium and nonequilibrium calculation methods was also investigated.
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We have studied phase equilibria in the quaternary system NaF–NaCl–NaBr–Na
2
CrO
4
. The results demonstrate that the continuous series of NaCl
x
Br
1 –
x
solid solutions persists in the system. ...The chemical composition and melting point (507°C) of a mixture with the composition corresponding to the quaternary minimum have been determined by differential thermal analysis, and its enthalpy of fusion (232 J/g) has been determined by differential scanning calorimetry. Its phase composition has been confirmed by X-ray diffraction. Theoretical and experimental techniques have been used to identify phase equilibria and the phase crystallization sequence and construct a 3D computer model of phase relations, which makes it possible to predict phase transformations for arbitrary representative points in the system studied.
The temperature dependence of density is calculated for an aqueous solution of sucrose by the molecular dynamics method. The coefficients of viscosity and diffusion are also obtained in the 273–343 K ...range of temperatures. The hydrodynamic radius of a sucrose molecule in an aqueous solution is calculated. The obtained data are compared with the experimental results.
Juçara fruit (Euterpe edulis) has received attention due to its similarities to Euterpe oleracea (Açaí). The aim of this study was to evaluate the cytotoxicity, bioactive compounds, antioxidant ...capacities and chemopreventive activities of the fruit pulps of six populations of E. edulis (J1-J6) and one population of E. espiritosantense from different ecological regions. ESI(−)-FT-ICR-MS was used to evaluate the pulp composition. The varieties J1 and J4 presented higher polyphenol contents, while J2 and J5 showed higher anthocyanin contents. ESI-FT-ICR MS identified cyanidin-3-rutinoside (J1, J2, J3, J4, J5, J7), protocatechuic acid, methylhydroxybenzoate hexoside and rutin (J1 to J7) and malvidin-glicoside (J2 to J5). The J2, J3, J4, J5 and J6 samples inhibited inducible nitric oxide synthase (iNOS). The chemoprevention biomarker quinone reductase was significantly induced by J6. Pulp from plants J3, J4, J6 and J7 significantly reduced the inflammatory cytokine TNF-α, and J6 was selected as having the most potential for cultivation and consumption.
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•Euterpe edulis presented high antioxidant capacity.•Juçara varieties were of good quality.•E. edulis Juçara fruit (J6) is indicating for in natura consumption or for use as nutraceutical.
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Three new withanolides, physaperuvin G (1), with physaperuvins I (2), and J (3), along with seven known derivatives (4–10), were isolated from the aerial parts of Physalis peruviana. ...The structures of 1–3 were determined by NMR, X-ray diffraction, and mass spectrometry. Compounds 1–10 were evaluated in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cells. Compounds 4, 5, and 10 with potent nitric oxide inhibitory activity in LPS-activated RAW 264.7 cells, with IC50 values in the range of 0.32–7.8μM. In addition, all compounds were evaluated for potential to inhibit tumor necrosis factor-alpha (TNF-α)-activated nuclear factor-kappa B (NF-κB) activity with transfected human embryonic kidney cells 293. Compounds 4–7 inhibited TNF-α-induced NF-κB activity with IC50 values in the range of 0.04–5.6μM.
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