Impact assessment of solid runoff on heavy metals migration during high floods on the Amur river

Inhomogeneity of the concentrations of chemical elements in the cross-section of the Amur River is considered as a function of the state of their soluble and suspended forms. Flooding of wetlands and urbanized areas contributes to the removal of pollutants into the river channel. The wide spread of fens on the left bank contributes to the concentration of organic matter along the left bank of the river. Terrigenous material mostly comes from the right bank, where agricultural fields are concentrated. The ratio of their concentrations is maintained by the duration of the flood. The mechanisms of redistribution of elements between their suspended and soluble forms have been studied. The mechanisms of sorption of chemical compounds on mineral and organic colloids are described. It was found that mineral colloids with a negative charge due to electrostatic attraction sorb electrically neutral compounds (hydroxoaqua complexes [Mn(OH)2(OH2]0, ammonia [Cu(NH3)4(OH)2]0. The role of organic material in the redistribution of chemical compounds between soluble and suspended forms is shown. Organic colloids with molecular mass > 5.0 kDa precipitate complex cations – [FeHSO4]+, [FeHSO4]2+, [CuHSO4]+. An organic substance with a molecular mass of <2.0 kDa has a greater complexing ability for Fe(2)3+, Cu2+, Zn2+, Mn2+ ions. They bind metals to organo-mineral complexes by chemical interaction and form mobile organo-mineral complexes and heteropolar salts.

Surface Characterization of Lipid Biomimetic Systems

Zeta potential and dipole potential measures are direct operational methodologies to determine the adsorption, insertion and penetration of ions, amphipathic and neutral compounds into the membranes of cells and model systems. From these results, the contribution of charged and dipole groups can be deduced. However, although each method may give apparent affinity or binding constants, care should be taken to interpret them in terms of physical meaning because they are not independent properties. On the base of a recent model in which the lipid bilayer is considered as composed by two interphase regions at each side of the hydrocarbon core, this review describes how dipole potential and zeta potential are correlated due to water reorganization. From this analysis, considering that in a cell the interphase region the membrane extends to the cell interior or overlaps with the interphase region of another supramolecular structure, the correlation of dipole and electrostatic forces can be taken as responsible of the propagation of perturbations between membrane and cytoplasm and vice versa. Thus, this picture gives the membrane a responsive character in addition to that of a selective permeability barrier when integrated to a complex system.

NEW COMPONENTS OF ALCEA NUDIFLORA EXTRACT AFTER MICROWAVE EXTRACTION

Alcea nudiflora (Lindl.) Boiss. (Malvaceae) has a wide area of growth in Central Asia, the Altai territory and Western Siberia and has long been used in folk and traditional medicine. Availability of the resource and long-term application practice makes Alcea nudiflora a promising source of valuable biologically active natural compounds. The chemical composition of A nudiflora has been studied after effective microwave assisted extraction (MAE) performed using solvents with different ability to convert microwave energy into heat: hexane, ethyl acetate, methyl tert-butyl ether (MTBE) and ethyl alcohol (EtOH). The selected MAE conditions enabled us to reduce significantly the extraction time and obtain extracts enriched with new compounds. The chemical composition of aboveground part extracts of Alcea nudiflora (Lindl.) Boiss was studied by applying GC/MS method. 13 acids were discovered for the first time, including 6 aromatic acids and 7 unbranched monobasic acids of unsaturated and saturated series, as well as 11 new neutral compounds, including 7 naphthalene derivatives.

Comparison of Neutral Compound Extraction from Archaeological Residues in Pottery Using Two Methodologies: A Preliminary Study

This study compares chloroform/methanol extraction and acidic methanol extraction of neutral compounds in absorbed lipid pottery residues from fourteen archaeological sherds. Previous studies have established that fatty acid extraction is more effective with acidic methanol extraction. This study suggests that acidic methanol extraction of neutral compounds, including sterols, alkanols, alkanes, and terpenoids, is more effective than or comparable to chloroform/methanol solvent extraction in most cases. The acidic methanol method extracts sterols, terpenoids, and alkanes more effectively than or comparably to chloroform/methanol extraction.

Synthesis of nitrogen-rich and thermostable energetic materials based on hetarenecarboxylic acids

Two series of both nitrogen-rich and thermostable energetic materials as well as their energetic salts based on hetarenecarboxylic acids are now described. Among these new compounds, the neutral compounds 3...

TADF: Enabling luminescent copper(I) coordination compounds for light-emitting electrochemical cells

The last decade has seen a surge of interest in the emissive behaviour of copper(I) coordination compounds, both neutral compounds that may have applications in organic light-emitting doides (OLEDs) and...

Novel primary phosphinecarboxamides derived from diamines

We describe the synthesis of N-functionalized phosphinecarboxamides obtained by reaction of the 2-phosphaethynolate anion (PCO–) with diamines, specifically hydrazine, methylenediamine and ethylenediamine. The resulting neutral compounds can be deprotonated to...

UV-Polymerized Vinylimidazolium Ionic Liquids for Permselective Membranes

Ionic liquids are highly charged compounds with increasing applications in material science. A universal approach to synthesize free-standing, vinylalkylimidazolium bromide-containing membranes with an adjustable thickness is presented. By the variation of alkyl side chains, membrane characteristics such as flux and mechanical properties can be adjusted. The simultaneous use of different ionic liquids (ILs) in the synthesis can also improve the membrane properties. In separation application, these charged materials allowed us to retain charged sugars, such as calcium gluconate, by up to 95%, while similar neutral compounds such as glucose passed the membrane. An analysis of the surface conditions using atomic force microscopy (AFM) confirmed the experimental data and explains the decreasing permeance and increased retention of the charged sugars.

Diradicalar Character and Ring Stability of Mesoionic Heterocyclic Oxazoles and Thiazoles by Ab Initio Mono and Multi-Reference Methods

Mesoionics are neutral compounds that cannot be represented by a fully covalent or purely ionic structure. Among the possible mesomeric structures of these compounds are the diradical electronic configurations. Theoretical and experimental studies indicate that some mesoionic rings are unstable, which may be related to a significant diradical character, that until then is not quantified. In this work, we investigated the diradical character of four heterocycles: 1,3-oxazol-5-one, 1,3-oxazol-5-thione, 1,3-thiazole-5-one, and 1,3-thiazole-5-thione. The oxazoles are known to be significatively less stable than thiazoles. DFT and ab initio single (B3LYP, MP2, CCSD, and QCISD) and ab initio multi-reference (MR-CISD) methods with three basis sets (6-311+G(d), aug-cc-pVDZ, and aug-cc-pVTZ) were employed to assess the diradical character of the investigated systems, in gas phase and DMSO solvent, from three criteria: (i) HOMO-LUMO energy gap, (ii) determination of energy difference between singlet and triplet wave functions, and (iii) quantification of the most significant diradical character (y0, determined in the unrestricted formalism). All of the results showed that the diradical character of the investigated systems is very small. However, the calculated electronic structures made it possible to identify the possible origin of the oxazoles instability, which can help the design of mesoionic systems with the desired properties.