Coordination of Cu(II) and Ni(II) in polymers imprinted so as to optimize amine chelate formation

Molecular imprinting has become an established technique. However, little was done on direct investigation of the sorbents produced. In the present work, en ESR method was used for the investigation of the complex formation processes within the sorbents imprinted with copper(II) and nickel(II). The sorbents were synthesized from a mixture of linear low molecular weight polyethyleneimine oligomers. The composition, structure and distribution of complexes in the resin phase were investigated. The effects of the synthesis conditions, loading degree and water content were examined. The presence of certain copper complexes was found to be a convenient characteristic of the imprinting efficiency. The optimum synthesis conditions for obtaining sorbents imprinted with copper(II) or nickel(II) were identified. The imprinting results in the improvement of the stability of the complexes and the selectivity and working capacity of the sorbents. The imprinted samples are also characterized by a more even distribution of chelating sites. The synthesis conditions and loading by ions allow for the regulation of the ratio between individual complexes and magnetic associates in the resin phase. This is a critical point on the future use of the metal containing imprinted sorbents as catalysts. (C) 2003 Published by Elsevier Science Ltd

Giant phonon anomalies in the pseudo-gap phase of TiOCl

We report infrared and Raman spectroscopy results of the spin-1/2 quantum magnet TiOCl. Giant anomalies are found in the temperature dependence of the phonon spectrum, which hint to unusual coupling of the electronic degrees of freedom to the lattice. These anomalies develop over a broad temperature interval, suggesting the presence of an extended fluctuation regime. This defines a pseudo-gap phase, characterized by a local spin-gap. Below 100 K a dimensionality cross-over leads to a dimerized ground state with a global spin-gap of about 2$\Delta_{spin}\approx$~430 K.Comment: 4 pages, 3 figures, for further information see http://www.peter-lemmens.d

Oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel

Liquid-phase oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel was studied by a kinetic method. Associative interactions between the substrate, oxidant, and gel were detected by voltammetry and ESR and IR spectroscopy.Russian Foundation for Basic Researc

Charge ordering and magneto-polarons in Na0.82_{0.82}CoO2_2

Using spectral ellipsometry, we have measured the dielectric function of a Na$_{0.82(2)}$CoO$_2$ crystal that exhibits bulk antiferromagnetism with T$_{N}$=19.8 K. We identify two prominent transitions as a function of temperature. The first one at 280 K involves marked changes of the electronic and the lattice response that are indicative of charge ordering in the CoO$_{2}$ layers. The second transition coincides with T$_{N}$=19.8 K and reveals a sizeable spin-charge coupling. The data are discussed in terms of charge ordering and formation of magneto-polarons due to a charge-induced spin-state transition of adjacent Co$^{3+}$ ions

Dynamics of pH-sensitive nitroxide radicals in water adsorbed in ordered mesoporous molecular sieves by EPR Spectroscopy

A spin pH probe technique was used to study the influence of the channel diameter on the EPR spectra of pH-sensitive nitroxide radicals (NR) located in the channels of the mesoporous molecular sieves MCM-41 and SBA-15 with diameters ranging from 2.3 to 8.1 nm. From EPR spectra analysis and the results of the NR retention by the mesoporous molecular sieves upon washing with an aqueous KCl solution, the regularities of NR molecular location inside the channels were studied. The obtained dependence of the fraction of the radical molecules in the fast motional regime (with the rotational correlation times, τc = 2 × 10-11 s-9 × 10-11s) in the channels of the mesoporous molecular sieves as a function of pH indicates that both NR in the fast and slow motional regime (with τc = 8 × 10 -9s-7 × 10-10s) may be used for estimation of the solution acidity inside the channels and of the near-surface electrical potential. © 2013 Elsevier Inc. All rights reserved

The formation of medical workers subjectity in the patient care institution environment from a position of the eco-psychological approach

The process of the medical worker's subjectity development as the realization of the ability to be a subject of the optional activity in the shape of professional performance in the patient care institution environment is analyse

Psychological characteristics of professional self-determination of senior pupils

The paper presents the results of the study indicate that there are agerelated, individual and typological differences in professional self-determination of senior pupils. The results show that the investigated groups of students to build professional per-spectives on the stage of the preliminary determination, there are certain difficultiesВ статье приведены результаты исследования, которые показывают, что существуют возрастные, индивидуальные и типологические различия в профессиональном самоопределении старшеклассников, а также определенные трудности в создании профессиональных перспектив на стадии оптаци

ULTRASONIC CAVITATION EFFECT ON THE FATTY ACID COMPOSITION OF LINSEED OIL-BASED EMULSIONS

Ultrasonic homogenization is a promising method of emulsion formation. Linseed oil containing polyunsaturated fatty acids in the optimal ratio was used as a control sample and the fat base of the emulsions. The effect of ultrasonic treatment can lead to a change in the percentage of fatty acids due to the acceleration and initiation of several chemical reactions. To assess the feasibility of using ultrasound in food production, the fatty acid composition of natural linseed oil and emulsions obtained from it, treated by ultrasound with different durations were studied. The study monitored the formation of radicals since increasing temperature and pressure during the collapse of cavitation bubbles initiates the formation of free hydrogen H- and hydroxyl OH-radicals within and next to them. These may initiate the oxidation of bioorganic compounds in the food product. The research results show that emulsions exposure to the ultrasound at a frequency of 20 kHz for 10, 20 and 30 minutes are capable to maintain the ratio of fatty acids while obtaining a homogeneous, finely dispersed and stable food emulsion. Deviations in the values characterizing the fatty acids content in the emulsions treated by ultrasound for 10, 20 and 30 minutes as compared with the control sample – linseed oil are insignificant (0.02±0.015% to 0.83±0.015). Using the method of electron paramagnetic resonance, the absence of free radicals was established both in the control sample – flax oil, and in emulsions obtained on its basis, homogenized using ultrasonic exposure. © 2023 Altai State University. All rights reserved