Search

Two express methods are presented in this paper. The first method is a high-resolution gamma-spectroscopic method based on a germanium detector, the second method is an IR-spectroscopic method. The applied complex of methods allows to determine the sources of uranium and thorium, identify the rhythms of uranium accumulation associated with regional events; identify areas with a high content of uranium due to the influence of local sources (faults, hydrothermal, etc.); determine the amount of authigenous uranium in the composition of total uranium; determine thermal maturity of organic matter in shales without their preliminary demineralization. To identify levels of increased uranium intensity in the high-carbon strata, a set of indicators has been proposed, which includes both applied indicators in practice of geological work and new indicators. New indicators have been tested on the collection of shale reference samples. For them, values ​​were established that characterize the processes of uranium accumulation and uranium removal. On the example of Ukhta Region according to the proposed indicators, the sections from the Vendian-Riphean to Domanic inclusive were interpreted. The performed work showed the possibility of comparing the calculated gamma-spectroscopic data with the data of other methods. This opens up a broader perspective for the use of express non-destructive gamma-spectroscopic method for detecting levels with a high content of uranium in the shale rocks, to which ore-bearing concentrations of a number of metals are also confined.

Introduction. This review describes the physicochemical properties that determine the use of hyaluronic acid in ophthalmology. We have studied methods for determining hyaluronic acid using various analytical methods.Text. Hyaluronic acid is a high molecular weight glycosaminoglycan that consists of repeating disaccharides of N-acetylglucosamine and D-glucuronic acid. Carboxyl, hydroxyl and acetoamide groups give hydrophilic properties to the molecule of this anionic heteropolysaccharide. Depending on how the hyaluronic acid is obtained, its molecular weight varies over a wide range. Researchers developed methods for controlling hyaluronic acid, which include the turbidimetric titration method, the method of high-performance capillary electrophoresis and high-performance liquid chromatography and IR spectroscopic method.Conclusion. Due to its properties, hyaluronic acid is widely used as an active ingredient in pharmaceutical preparations. Today, there are a number of methods for the determination of hyaluronic acid, including the method of turbidimetric titration, the method of capillary electrophoresis. High performance liquid chromatography (HPLC) and IR spectroscopy methods are presented in the Japanese Pharmacopoeia and the European Pharmacopoeia. These techniques are widely used due to their high reproducibility, accuracy, and relative simplicity.

Optical spectroscopy is a powerful tool to interrogate quantum states of matter. We present simulation results for the cross-polarized two-dimensional electronic spectra of the light-harvesting system LH2 of purple bacteria. We identify a spectral feature on the diagonal, which we assign to ultrafast coherence transfer between degenerate states. The implication for the interpretation of previous experiments on different systems and the potential use of this feature are discussed. In particular, we foresee that this kind of feature will be useful for identifying mixed degenerate states and for identifying the origin of symmetry breaking disorder in systems like LH2. Furthermore, this may help identify both vibrational and electronic states in biological systems such as proteins and solid-state materials such as hybrid perovskites.

Introduction. Composite materials on the basis of epoxy resin find wide application as adhesives, coatings and structural materials whose properties it is possible to regulate by introduction of various additives including disperse fillers in the epoxy binder. Positively influencing properties of epoxy materials, the disperse fillers can reduce water resistance of the materials. This work is aimed at studying of influence of polar and nonpolar disperse fillers on structure and water absorption of the epoxy materials. Materials and methods. When obtaining composite materials, the following components were used: ED-20 epoxy resin (state standard GOST 10587-84), dibutylphthalate (state standard GOST 8728-88) plasticizer, polyethylenepolyamine (specification TU 2413-357-00203447-99) hardener, marshallite (state standard GOST 9077-82) and graphite (state standard GOST 17022-81) disperse fillers. The structure of samples was investigated by means of IR-spectroscopy method. Water absorption was determined in boiling water using the standard gravimetric method (state standard GOST 4650-2014 (ISO 62:2008)) and evaluated by sample mass variation within 120 days. Results. As a result of the conducted researches, the optimum content of the marshallite and graphite fillers in epoxy materials is established. When mass filler-to-binder ratio is equal to 15/85, water absorption of the materials is minimum. The IR-spectroscopy method showed that introduction of the marshallite polar filler in the epoxy binder promotes ordering of material structure due to formation of hydrogen bond between reactive groups of the filler and resin. Localizing in amorphous areas, particles of the graphite nonpolar filler lead to weakening of the hydrogen-bond system. Interaction of marshallite-filled samples with water is accomplished at the swelling mode, with equilibrium degree of swelling about 1 %. The mechanism of interaction of graphite-filled samples with water includes the alternating stages of dissolution and swelling, which are more expressed as compared with check samples. Conclusions. Water resistance of epoxy materials filled with disperse fillers is defined by a microstructure of the cured resin. Introduction of the marshallite polar filler in the epoxy binder leads to ordering of material structure that results in increasing of water absorption. Introduction of the graphite nonpolar filler in the epoxy binder leads to disordering of material structure that results in reducing of water absorption. Lower value of water absorption of graphite-filled epoxy material is connected with partial dissolution of the sample. Using nonpolar fillers is inexpedient for epoxy materials contacting with water.

Spectroscopic data, depending on an experimentally controllable variable, contains a wealth of information for researchers. However, complex spectra with overlapping peaks and multiple transitions complicate its straightforward interpretation and often the full contained information cannot be extracted. Here, the Spectram toolbox for MATLAB® and GNU Octave is described which was developed to analyse such data by a method based on singular value decomposition (SVD) and transition model coupled recombination. The method employs user-defined transition models, which depend on the control variable and are often known, or empirical descriptions of the transitions, which often can be guessed, to deconvolute such data. The outcome are the spectral components associated to the transitions and the model parameters. Both can be directly interpreted in terms of their physical meaning. Spectram can be applied to any desired spectroscopic technique and gives full freedom in the choice of the applied models, making it highly reusable. Funding statement: Funding by the European Union’s Horizon 2020 research and innovation program under a Marie Skłodowska-Curie Grant (Agreement No. 705857) is acknowledged.

A sorbent was synthesized by thermal processing of sapropel residue after the extraction of humic acids, and subsequently modified with polyhexamethyleneguanidine and humic acids pre-isolated from sapropel. The humic sorbent transformations have been studied under air at the temperature range of 20-1000°C by thermal analysis. The presence of various functional groups on the surface of a humic sorbent from sapropel has been confirmed by IR-spectroscopy. Sorption of palladium and nickel ions from water solutions was studied. The value of static capacity of the synthesized humic sorbent for palladium was 38.8±2.7, and for nickel ions was 32.0±1.8 mg/g, respectively. It has been established that the equilibrium of sorption was described by the Freundlich isotherm equation.

We analysed 44 fine-grained and scoriaceous micrometeorites. A bulk mid-IR spectrum (8–13 μm) for each grain was collected and the entire micrometeorite population classified into 5 spectral groups, based on the positions of their absorption bands. Corresponding carbonaceous Raman spectra, textural observations from SEM-BSE and bulk geochemical data via EMPA were collected to aid in the interpretation of mid-IR spectra. The 5 spectral groups identified correspond to progressive thermal decomposition. Unheated hydrated chondritic matrix, composed predominantly of phyllosilicates, exhibit smooth, asymmetric spectra with a peak at ∼10 μm. Thermal decomposition of sheet silicates evolves through dehydration, dehydroxylation, annealing and finally by the onset of partial melting. Both CI-like and CM-like micrometeorites are shown to pass through the same decomposition stages and produce similar mid-IR spectra. Using known temperature thresholds for each decomposition stage it is possible to assign a peak temperature range to a given micrometeorite. Since the temperature thresholds for decomposition reactions are defined by the phyllosilicate species and the cation composition and that these variables are markedly different between CM and CI classes, atmospheric entry should bias the dust flux to favour the survival of CI-like grains, whilst preferentially melting most CM-like dust. However, this hypothesis is inconsistent with empirical observations and instead requires that the source ratio of CI:CM dust is heavily skewed in favour of CM material. In addition, a small population of anomalous grains are identified whose carbonaceous and petrographic characteristics suggest in-space heating and dehydroxylation have occurred. These grains may therefore represent regolith micrometeorites derived from the surface of C-type asteroids. Since the spectroscopic signatures of dehydroxylates are distinctive, i.e. characterised by a reflectance peak at 9.0–9.5 μm, and since the surfaces of C-type asteroids are expected to be heated via impact gardening, we suggest that future spectroscopic investigations should attempt to identify dehydroxylate signatures in the reflectance spectra of young carbonaceous asteroid families.

O.I. Bol’shakov1, bolshakovoi@susu.ru V.A. Potemkin1, potemkinva@susu.ru M.A. Grishina1, grishinama@susu.ru A.S. Galushko2, galas74@inbox.ru S.V. Merzlov1, bostonbruins.2011.6@gmail.com R.S. Morozov1, yanatulskoi@mail.ru A.O. Shchelokov1, artyom.shchelokov@yandex.ru V.V. Popov3, Popov.ioc@gmail.com 1 South Ural State University, Chelyabinsk, Russian Federation 2 Institute of Organic Chemistry of the Russian Academy of Sciences, Moscow, Russian Federation 3 Wayne State University, Detroit, MI, USA Большаков Олег Игоревич – кандидат химических наук, научный сотрудник Управления научной и инновационной деятельности, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: bolshakovoi@susu.ru Потемкин Владимир Александрович – научный сотрудник Управления научной и инновационной деятельности, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: potemkinva@susu.ru Гришина Мария Александровна – главный научный сотрудник Высшей медико- биологической школы, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: grishinama@susu.ru Галушко Алексей Сергеевич – аспирант лаборатории металлокомплексных и наноразмерных катализаторов (№ 30), Институт органической химии им. Н.Д. Зелинского, РАН. 119991, г. Москва, Ленинский пр. 47. E-mail: galas74@inbox.ru Мерзлов Сергей Владимирович – инженер кафедры экологии и природопользования, химический факультет, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: bostonbruins.2001.6@gmail.com Морозов Роман Сергеевич – аспирант кафедры экологии и природопользования, Южно- Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: yanatulskoi@mail.ru Щелоков Артем Олегович – студент кафедры химической технологии, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: artyom.shchelokov@yandex.ru Попов Вадим Владимирович – постдокторант факультета биомедицинской инженерии, Университет Уэйна, Wayne State University, 42. W. Warren Ave. Detroit, MI 48202, MI, USA. E-mail: popov.ioc@gmail.com Affinity characteristics of biomolecules, such as peptides and proteins, towards inorganic surfaces in general and to titanium oxide in particular become crucial in biotechnology and bionanotechnology. Amino acids are often used as “model” bits of peptides or proteins for studying their properties in different environments, and/or developing functional surfaces. Despite the great demand for knowledge about amino acid interactions with metal oxide surface, studies on the issue lack in consistency and represent a fragmentary picture. This paper is an attempt to study amino acid adsorption on nanocrystalline anatase systematically at uniform conditions. Features of the L-alanine adsorption have been revealed and interpreted with quantum-chemical calculations. Особенности взаимодействия биомолекул, таких как протеины и пептиды с неорганическими поверхностями вообще и с оксидом титана в частности становятся ключевым фактором биотехнологии и бионанотехнологии. Аминокислоты часто используются в качестве модельных фрагментов пептидов и протеинов для изучения их свойств в различных средах и при изучении новых поверхностей. Несмотря на высокий запрос на фундаментальные представления о взаимодействии биомолекул с поверхностью оксида титана, знания в этой области представлены фрагментарно и не дают целостной картины. В этой статье проведена попытка изучения сорбции аминокислот на оксиде титана в унифицированных условиях. Сорбция L-аланина была интерпретирована квантово- механическим моделированием. The reported study was funded by RFBR according to the research project № 15-03-07834-a.

Elements the 3 and 5 of groups of the Periodic System and carbon are the most important impurities in silicon. The estimation technique of carbon, boron and phosphorus impurity content in high-purity monosilane has been proposed. The technique involves the preparation of polycrystalline silicon by silane decomposition, growing a test single crystal by the floating zone melting method and analysis of single crystal samples by IR spectroscopy. Calculation of impurity concentration in polycrystalline silicon has been performed using results on their content in the test single crystal samples, data on impurity distribution in the liquid-solid system and sample coordinates along the ingot length. Effective impurity distribution coefficients in the solid-liquid system for specific growing conditions have been calculated using the Burton-Prim-Slichter equation. Results for the test silicon samples with natural isotopic composition and 28Si isotope enriched ones obtained from monosilane samples with different impurity contents have been reported. Results on IR spectroscopic studies of impurity composition for the test silicon single crystal are in agreement with the concentration data obtained by chromatography. The concentration of 3 and 5 group impurities in monosilane were in the range 4x10−9−2x10−6 at. %, and for carbon concentration was 2x10−6–6x10−4 at.%. The measurement uncertainty by IR spectroscopy does not exceed 15% for carbon impurity and 20% for boron and phosphorus. We show that the upper limit of carbon content in monosilane detected using this method is determined by its solubility in silicon, while the bottom limit depends on the detection accuracy of the IR spectroscopy technique and possible background contamination.

We present a theory for modeling fluorescence-detected two-dimensional electronic spectroscopy of multichromophoric systems. The theory is tested by comparison of the predicted spectra of the light-harvesting complex LH2 with experimental data. A qualitative explanation of the strong cross-peaks as compared to conventional two-dimensional electronic spectra is given. The strong cross-peaks are attributed to the clean ground-state signal that is revealed when the annihilation of exciton pairs created on the same LH2 complex cancels oppositely signed signals from the doubly excited state. This annihilation process occurs much faster than the nonradiative relaxation. Furthermore, the line shape difference is attributed to slow dynamics, exciton delocalization within the bands, and intraband exciton-exciton annihilation. This is in line with existing theories presented for model systems. We further propose the use of time-resolved fluorescence-detected two-dimensional spectroscopy to study state-resolved exciton-exciton annihilation.

The idea that excitonic (electronic) coherences are of fundamental importance to natural photosynthesis gained popularity when slowly dephasing quantum beats (QBs) were observed in the two-dimensional electronic spectra of the Fenna–Matthews–Olson (FMO) complex at 77 K. These were assigned to superpositions of excitonic states, a controversial interpretation, as the strong chromophore–environment interactions in the complex suggest fast dephasing. Although it has been pointed out that vibrational motion produces similar spectral signatures, a concrete assignment of these oscillatory signals to distinct physical processes is still lacking. Here we revisit the coherence dynamics of the FMO complex using polarization-controlled two-dimensional electronic spectroscopy, supported by theoretical modelling. We show that the long-lived QBs are exclusively vibrational in origin, whereas the dephasing of the electronic coherences is completed within 240 fs even at 77 K. We further find that specific vibrational coherences are produced via vibronically coupled excited states. The presence of such states suggests that vibronic coupling is relevant for photosynthetic energy transfer. The implications of coherence signals for the transfer of energy within the Fenna–Matthews–Olson complex of photosynthetic green sulfur bacteria is a well debated topic. Now, polarization-controlled 2D spectroscopy — aided by vibronic exciton modelling — has enabled the characterization of all such coherences and determination of their physical origins; while electronic coherences dephase extremely rapidly, ground- and excited-state vibrational coherences dominate.

International audience; The large pore vanadium(III) trimesate MIL-100(V), i.e. V3O(H2O)(2)X[C9H3O6](2)center dot yH(2)O with x = (C9H5O6)(z)(-), y approximate to 3 and z approximate to 0.3, has been synthesized under hydrothermal conditions (MIL stands for Materials from Institute Lavoisier). Its structure, which crystallizes in the space group Fd-3m (No. 227) with a = 73.0286(2) angstrom, V= 389474.4(2) angstrom(3), exhibits a zeotype architecture with mesoporous cages of approx. 25 and 29 angstrom diameter, accessible through microporous windows of 5.5 and 8.9 angstrom diameter. Synchrotron X-ray powder diffraction analysis confirms its isostructural character with previously reported MIL-100(Cr, Fe, Al) solids. Its thermal stability under O-2 and N-2, up to 523 K (250 degrees C), is comparable to that of MIL-100(Fe). Preliminary gas adsorption experiments and in situ IR-spectroscopy after NO exposure reveal that MIL-100(V) combines high sorption capacities and co-ordinatively unsaturated vanadium sites in different oxidation states (+III and +IV). With these properties this material could be a promising candidate for specific sorption or redox catalytic applications. (C) 2011 Elsevier Inc. All rights reserved.

The annealing effect in the temperature range from 350 to 450 °С on the behavior of interstitial oxygen Оi dissolved in germanium and on optical properties of single crystals has been investigated by Fourier transformed infrared spectrometry. It was found that oxygen band maximum of 843 cm–1 shifted toward the 856 cm−1 with oxygen concentration increasing after annealing at the oxygen partial pressure ranged from 1 to 103 Pа. The annealing at lower values led to the decrease of 843 cm–1 band intensity due to the formation of thermal donors (TD) on the basis of dissolved oxygen atoms Оi. It was established that TD formation and the decrease of unbound oxygen concentration affected optical properties of the crystals.

Biocomposites based on carbonate-substituted hydroxyapatite synthesized from the biological source of calcium (Goloshchapov et al., 2013) and organic primer on the basis of amino acids found in the enamel tubules of teeth, namely, arginine, histidine, lysine and hyaluronic acid were obtained and studied in this work. Incorporation of organic primer into biocomposite formulation allowed us to obtain the emission characteristics (luminescence) that were identical to those inherent to the native tissues of the human tooth (enamel and dentine). Keywords: Biocomposites, IR-spectroscopy, Optical and emission properties, Hydroxyapatite, Human tooth tissues