Graphene materials for lead (II) extraction: an equilibrium study

The present paper describes a study on the adsorption of lead (II) ions on graphene materials obtained via exfoliation of a hydrolyzed expanded graphite intercalation compound. An equilibrium studies were performed implementing the empirical Freundlich and Langmuir isotherm models. It was found that all the isotherms are fitted well by those models, indicating the efficiency of the graphene materials as an adsorbent of heavy metals. The applicability of the two isotherms for sorption processes shows that both monolayer adsorption and heterogeneous energetic distribution of active sites on the adsorbent surface may take place. The maximum experimental lead (II) adsorption capacities of the materials under study – few-layered oxidized graphene suspension, multi-layered graphene paste, and few-layered graphene paste – were found to be 850, 230 and 170 mg/g, respectively. Due to the high sorption characteristics and unique physical and chemical properties of these materials, the adsorption technologies developed herein can act as good sustainable options for the future in heavy metal removal from industrial effluents

Unusual shift in the visible absorption spectrum of an active ctenophore photoprotein elucidated by time‑dependent density functional theory

Active hydromedusan and ctenophore Ca2+-regulated photoproteins form complexes consisting of apoprotein and strongly non-covalently bound 2-hydroperoxycoelenterazine (an oxygenated intermediate of coelenterazine). Whereas the absorption maximum of hydromedusan photoproteins is at 460–470 nm, ctenophore photoproteins absorb at 437 nm. Finding out a physical reason for this blue shift is the main objective of this work, and, to achieve it, the whole structure of the protein–substrate complex was optimized using a linear scaling quantum–mechanical method. Electronic excitations pertinent to the spectra of the 2-hydroperoxy adduct of coelenterazine were simulated with time-dependent density functional theory. The dihedral angle of 60° of the 6-(p-hydroxy)-phenyl group relative to the imidazopyrazinone core of 2-hydroperoxycoelenterazine molecule was found to be the key factor determining the absorption of ctenophore photoproteins at 437 nm. The residues relevant to binding of the substrate and its adopting the particular rotation were also identified

Evaluation of the traffic signal regulation efficiency of crossroads with unstable transport demand by time

The article describes the results of the research, whose goal is to assess the effectiveness of the traffic light operation at crossroads with unstable transport demand in terms of time and directions. The modern way of cities development consists in creation of sustainable, and, hence, safe, harmless and comfortable environment for residing. This determines the separation of urban and industrial areas, the creation of transport infrastructure, in particular crossroads, which are equipped with traffic lights. As a rule, it is characterized by unstable transport demand in the direction of entry and exit from the territory of enterprises, which causes an inadvertent increase in the idle time of vehicles in the main direction. In the course of experimental studies, the authors found that the crossroads under consideration are parts of the road network that connect the industrial and urban areas, which causes a high traffic intensity in the main areas. At the same time, the share of ineffective resolving phase for entry and exit from the territory of the enterprise reaches 70-80%, which increases the idle time of vehicles in the main direction. The authors proposed an indicator that characterizes the proportion of inefficient operation of the traffic signal

Graphene materials for lead (II) extraction: an equilibrium study

The present paper describes a study on the adsorption of lead (II) ions on graphene materials obtained via exfoliation of a hydrolyzed expanded graphite intercalation compound. An equilibrium studies were performed implementing the empirical Freundlich and Langmuir isotherm models. It was found that all the isotherms are fitted well by those models, indicating the efficiency of the graphene materials as an adsorbent of heavy metals. The applicability of the two isotherms for sorption processes shows that both monolayer adsorption and heterogeneous energetic distribution of active sites on the adsorbent surface may take place. The maximum experimental lead (II) adsorption capacities of the materials under study – few-layered oxidized graphene suspension, multi-layered graphene paste, and few-layered graphene paste – were found to be 850, 230 and 170 mg/g, respectively. Due to the high sorption characteristics and unique physical and chemical properties of these materials, the adsorption technologies developed herein can act as good sustainable options for the future in heavy metal removal from industrial effluents

Graphene materials for lead (II) extraction: an equilibrium study

The present paper describes a study on the adsorption of lead (II) ions on graphene materials obtained via exfoliation of a hydrolyzed expanded graphite intercalation compound. An equilibrium studies were performed implementing the empirical Freundlich and Langmuir isotherm models. It was found that all the isotherms are fitted well by those models, indicating the efficiency of the graphene materials as an adsorbent of heavy metals. The applicability of the two isotherms for sorption processes shows that both monolayer adsorption and heterogeneous energetic distribution of active sites on the adsorbent surface may take place. The maximum experimental lead (II) adsorption capacities of the materials under study – few-layered oxidized graphene suspension, multi-layered graphene paste, and few-layered graphene paste – were found to be 850, 230 and 170 mg/g, respectively. Due to the high sorption characteristics and unique physical and chemical properties of these materials, the adsorption technologies developed herein can act as good sustainable options for the future in heavy metal removal from industrial effluents

Dynamics of Changes in the Gut Microbiota of Healthy Mice Fed with Lactic Acid Bacteria and Bifidobacteria

Probiotics are living microorganisms that provide numerous health benefits for their host. Probiotics have various effects on the body; for example, they change gut microbiota, improve the integrity of the epithelial barrier and have anti-inflammatory effects. The use of probiotic supplements that are based on lactic acid bacteria and bifidobacteria is one of the approaches that are used to balance gut microflora. In our study, we evaluated the effects of supplements, which were based on members of the Lactobacillaceae family and bifidobacteria, on the gut microbiome of healthy mice using the 16S rRNA sequencing method. The data that were obtained demonstrated that when mice received the probiotic supplements, statistically significant changes occurred in the composition of the microbiome at the phylum level, which were characterized by an increase in the number of Actinobacteriota, Bacteroidota, Verrucomicrobia and Proteobacteria, all of which have potentially positive effects on health. At the generic level, a decrease in the abundance of members of the Nocardioides, Helicobacter and Mucispirillum genus, which are involved in inflammatory processes, was observed for the group of mice that was fed with lactic acid bacteria. For the group of mice that was fed with bifidobacteria, a decrease was seen in the number of members of the Tyzzerella and Akkermansia genus. The results of our study contribute to the understanding of changes in the gut microbiota of healthy mice under the influence of probiotics. It was shown that probiotics that are based on members of the Lactobacillaceae family have a more positive effect on the gut microbiome than probiotics that are based on bifidobacteria

New Hybrid Compounds Combining Fragments of Usnic Acid and Thioether Are Inhibitors of Human Enzymes TDP1, TDP2 and PARP1

Tyrosyl-DNA phosphodiesterase 1 (TDP1) catalyzes the cleavage of the phosphodiester bond between the tyrosine residue of topoisomerase 1 (TOP1) and the 3′ phosphate of DNA in the single-strand break generated by TOP1. TDP1 promotes the cleavage of the stable DNA–TOP1 complexes with the TOP1 inhibitor topotecan, which is a clinically used anticancer drug. This article reports the synthesis and study of usnic acid thioether and sulfoxide derivatives that efficiently suppress TDP1 activity, with IC50 values in the 1.4–25.2 μM range. The structure of the heterocyclic substituent introduced into the dibenzofuran core affects the TDP1 inhibitory efficiency of the compounds. A five-membered heterocyclic fragment was shown to be most pharmacophoric among the others. Sulfoxide derivatives were less cytotoxic than their thioester analogs. We observed an uncompetitive type of inhibition for the four most effective inhibitors of TDP1. The anticancer effect of TOP1 inhibitors can be enhanced by the simultaneous inhibition of PARP1, TDP1, and TDP2. Some of the compounds inhibited not only TDP1 but also TDP2 and/or PARP1, but at significantly higher concentration ranges than TDP1. Leader compound 10a showed promising synergy on HeLa cells in conjunction with the TOP1 inhibitor topotecan