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In the present work, ternary mixtures of Acetaminophen, Ascorbic acid and Uric acid were resolved using the Electronic tongue (ET) principle and Cyclic voltammetry (CV) technique. The screen-printed integrated electrode array having differentiated response for the three oxidizable compounds was formed by Graphite, Prussian blue (PB), Cobalt (II) phthalocyanine (CoPc) and Copper oxide (II) (CuO) ink-modified carbon electrodes. A set of samples, ranging from 0 to 500 &micro, mol&middot, L&minus, 1, was prepared, using a tilted (33) factorial design in order to build the quantitative response model. Subsequently, the model performance was evaluated with an external subset of samples defined randomly along the experimental domain. Partial Least Squares Regression (PLS) was employed to construct the quantitative model. Finally, the model successfully predicted the concentration of the three compounds with a normalized root mean square error (NRMSE) of 1.00 and 0.99 for the training and test subsets, respectively, and R2 &ge, 0.762 for the obtained vs. expected comparison graphs. In this way, a screen-printed integrated electrode platform can be successfully used for voltammetric ET applications.

This work reports on the environmental friendly enzymatic dyeing of wool and leather performed at low temperature and mild pH conditions without any dyeing auxiliaries. The substrates have been dyed with “in situ” generated pigment by means of laccase-catalyzed oxidative coupling of dye modifier 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and dye precursor 1,3-benzenediol in a batchwise process. The process reaction variables (laccase, precursor and modifier concentrations, temperature and dyeing time) were optimized by response surface methodology using an appropriate experimental design. The temperature, precursor concentration, interaction between precursor and modifier and time are the most important factors in the dyeing process. The best-optimized wool dyeing conditions (2 h reaction time, 50 μl laccase (0.1 U), 500 mM precursor, 10 mM modifier at 40 °C) were then successfully applied onto leather material. The enzymatic-dyeing optimized process can be successfully performed on wool and leather at low temperature and mild pH obtaining different hues and depths of shades by varying the modifier concentration and time. The colouring enzymatic system has a good reusability (which has a huge advantage in terms of cost reduction) and washing durability and is comparable in terms of fastness properties to the traditional dyeing process for both wool and leather., The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for funding the project UID/CTM/00264/2019 and A. Zille contract IF/00071/2015.

Highlights • An SFC method has been developed for the analysis of polar urinary metabolites. • 12 stationary phases, 9 modifier additives and 3 temperatures were evaluated. • DIOL and 2-PIC columns provide highest peak capacity and overall resolution. • Ammonium formate, ammonium hydroxide and water considerably improved separation. • Alkylamine additives should be strongly considered for polar SFC-UV analysis., Supercritical fluid chromatography (SFC) is frequently used for the analysis and separation of non-polar metabolites, but remains relatively underutilised for the study of polar molecules, even those which pose difficulties with established reversed-phase (RP) or hydrophilic interaction liquid chromatographic (HILIC) methodologies. Here, we present a fast SFC-MS method for the analysis of medium and high-polarity (−7 ≤ cLogP ≤ 2) compounds, designed for implementation in a high-throughput metabonomics setting. Sixty polar analytes were first screened to identify those most suitable for inclusion in chromatographic test mixtures; then, a multi-dimensional method development study was conducted to determine the optimal choice of stationary phase, modifier additive and temperature for the separation of such analytes using SFC. The test mixtures were separated on a total of twelve different column chemistries at three different temperatures, using CO2-methanol-based mobile phases containing a variety of polar additives. Chromatographic performance was evaluated with a particular emphasis on peak capacity, overall resolution, peak distribution and repeatability. The results suggest that a new generation of stationary phases, specifically designed for improved robustness in mixed CO2-methanol mobile phases, can improve peak shape, peak capacity and resolution for all classes of polar analytes. A significant enhancement in chromatographic performance was observed for these urinary metabolites on the majority of the stationary phases when polar additives such as ammonium salts (formate, acetate and hydroxide) were included in the organic modifier, and the use of water or alkylamine additives was found to be beneficial for specific subsets of polar analytes. The utility of these findings was confirmed by the separation of a mixture of polar metabolites in human urine using an optimised 7 min gradient SFC method, where the use of the recommended column and co-solvent combination resulted in a significant improvement in chromatographic performance.

Investigation of the process of structure formation of samples of hydrated cement compositions on the nano level is conducted with the help of the method of small angle neutron scattering (neutron wavelength is λ=0.3 nm) both on the basis of Portland cement without additives and that modified by various nanoadditives and nanomodifiers of artificial (alpha aluminium oxide, gamma aluminium oxide) and technogenic (sludge) origin, as well as by complex additives containing surfactants. Dynamics of changes of structural parameters of samples of cement compositions depending on time is analyzed. Changes of correlation functions of scattering objects and fractal dimensions are observed. It is substantiated that Portland cement compositions are fractal clusters.

The study of the composition and preparability of two samples of tailings dumped at the Yaroslavl Mining Company revealed the following contents: CaF2 - 15.2 and 20.7%, CaCO3 - 13.3 and 10.2%, and Zn - 0.49 and 0.38%. The volume of the stockpiled wastes is estimated at 30 million tons. The need for fine material grinding at the stage of preparation for flotation was shown, and the efficient fluorite concentration was possible with technical solutions found. The determined optimal parameters of the flotation acid-base condition provided neutralization of the negative influence of salts and slimes left by the previous processing cycle. It has been established that a mixture of ammonium and lignosulfonates was effective as a modifier. The extraction of sample 1 yielded 52% of fluorite extraction to the concentrates with 92.2-92.8% fluorite content, and more than 69% when beneficiating the sample 2. Upgrading of the concentrate quality is only possible through transferring to flotation tails of the most contaminated fluorite grains impregnated with silicate minerals, but this is followed by a significant extraction reduction. The concentration of sphalerite to a separate product occurs with low effectiveness. The inclusion of sulfide flotation in the circuit head can improve the fluorite cycle efficiency: extraction of CaF2 to the concentrates of FF-92 brand may reach 70%.

This investigation is based on the results of the experiments on small angle neutron scattering (neutron wavelength is λ=0.3 nm) and goes into patterning trans-atomic-level structure of hydrated portland cement compositions. The following structural parameters are determined: particle size distribution, porosity, fractal dimensionality. The paper stresses the effect of both artificial (γAl2O3, carbon materials) and technogenic (slurry) nanoagents and nanomodifiers on these structural parameters as well as the effect of complex additives with surface-active agents.

CONSPECTUS: The modification of heterogeneous catalysts through the chemisorption of chiral molecules is a method to create catalytic sites for enantioselective surface reactions. The chiral molecule is called a chiral modifier by analogy to the terms chiral auxiliary or chiral ligand used in homogeneous asymmetric catalysis. While there has been progress in understanding how chirality transfer occurs, the intrinsic difficulties in determining enantioselective reaction mechanisms are compounded by the multisite nature of heterogeneous catalysts and by the challenges facing stereospecific surface analysis. However, molecular descriptions have now emerged that are sufficiently detailed to herald rapid advances in the area. The driving force for the development of heterogeneous enantioselective catalysts stems, at the minimum, from the practical advantages they might offer over their homogeneous counterparts in terms of process scalability and catalyst reusability. The broader rewards from their study lie in the insights gained on factors controlling selectivity in heterogeneous catalysis. Reactions on surfaces to produce a desired enantiomer in high excess are particularly challenging since at room temperature, barrier differences as low as similar to 2 kcal/mol between pathways to R and S products are sufficient to yield an enantiomeric ratio (er) of 90:10. Such small energy differences are comparable to weak interadsorbate interaction energies and are much smaller than chemisorption or even most physisorption energies.In this Account, we describe combined experimental and theoretical surface studies of individual diastereomeric complexes formed between chiral modifiers and prochiral reactants on the Pt(111) surface. Our work is inspired by the catalysis literature on the enantioselective hydrogenation of activated ketones on cinchona-modified Pt catalysts. Using scanning tunneling microscopy (STM) measurements and density functional theory (DFT) calculations, we probe the structures and relative abundances of noncovalently bonded complexes formed between three representative prochiral molecules and (R)-(+)-1-(1-naphthyl)ethylamine ((R)-NEA). All three prochiral molecules, 2,2,2-trifluoroacetophenone (TFAP), ketopantolactone (KPL), and methyl 3,3,3-trifluoropyruvate (MTFP), are found to form multiple complexation configurations around the ethylamine group of chemisorbed (R)-NEA. The principal intermolecular interaction is NH center dot center dot center dot O H-bonding. In each case, submolecularly resolved STM images permit the determination of the prochiral ratio (pr), pro-R to pro-S, proper to specific locations around the ethylamine group. The overall pr observed in experiments on large ensembles of KPL (R)-NEA complexes is close to the er reported in the literature for the hydrogenation of KPL to pantolactone on (R)-NEA-modified Pt catalysts at 1 bar H-2. The results of independent DFT and STM studies are merged to determine the geometries of the most abundant complexation configurations. The structures reveal the hierarchy of chemisorption and sometimes multiple H-bonding interactions operating in complexes. In particular, privileged complexes formed by KPL and MTFP reveal the participation of secondary CH center dot center dot center dot O interactions in stereocontrol. State-specific STM measurements on individual TFAP (R)-NEA complexes show that complexation states interconvert through processes including prochiral inversion. The state-specific information on structure, prochirality, dynamics, and energy barriers delivered by the combination of DFT and STM provides insight on how to design better chiral modifiers.

Defining a method development methodology for achiral drug impurity profiling in SFC requires a number of steps. Initially, diverse stationary phases are characterized and a small number of orthogonal or dissimilar phases are selected for further method development. In this paper, we focus on a next step which is the investigation of the modifier composition on chromatographic selectivity. A solvent-triangle based approach is used in which blends of organic solvents, mainly ethanol (EtOH), propanol (PrOH), acetonitrile (ACN) and tetrahydrofuran (THF) mixed with methanol (MeOH) are tested as modifiers on six dissimilar stationary phases. The tested modifier blends were composed to have equal eluotropic strengths as calculated on bare silica. The modifier leads to minor changes in terms of elution order, retention and mixture resolution. However, varying only the modifier composition on a given stationary phase does not lead to the creation of dissimilar systems. Therefore the modifier composition is an optimization parameter, with the stationary phase being the factor determining most the selectivity of a given mixture in achiral SFC.

A systematic study involving the use and optimization of gas phase modifiers in quantitative differential mobility- mass spectrometry (DMS-MS) analysis is presented using mucleoside-adduct biomarkers of DNA damage as an important reference point for analysis in complex matrices. Commonly used polar protic and polar aprotic modifiers have been screened for use against two deoxyguanosine adducts of DNA: N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-4-ABP) and N-(deoxyguanosin-8-y1)-2-amino-l-methyl-6-phenylimidazo[4,5-b]pyridine (dG-C8-PhIP). Particular attention was paid to compensation voltage (CoV) shifts, peak shapes and product ion signal intensities while optimizing the DMS-MS conditions. The optimized parameters were then applied to rapid quantitation of the DNA adducts in calf thymus DNA. After a protein precipitation step, adduct levels corresponding to less than one modification in 106 normal DNA bases were detected using the DMS-MS platform. Based on DMS fundamentals and ab-initio thermochemical results we interpret the complexity of DMS modifier responses in terms of thermal activation and the development of solvent shells. At very high bulk gas temperature, modifier dipole moment may be the most important factor in cluster formation and cluster geometry in mobility differences, but at lower temperatures multi-neutral clusters are important and less predictable. This work provides a useful protocol for targeted DNA adduct quantitation and a basis for future work on DMS modifier effects.

In the work spent on sturgeon kinds of fishes and their hybrids, effects of interaction of enzymes with modifiers of the various nature (carbohydrates, amino acids) have been established. For maltase and caseinlitik proteinase it is shown izosteric effect.

International audience; Carbopol is a family of high molecular weight cross-linked poyacrylic acids widely used as thickening agents in several industrial applications. In this work, the structure of Carbopol 974P NF was investigated at pH 7.4 by means of capillary viscometry, dynamic rheology, fluorescence microscopy, and electron microscopy in the dilute and semi-dilute (hydrogel) state. Especially, high-pressure freezing technique has proved to be a technique of choice to visualize the Carbopol hydrogel microstructure through cryo-scanning electron microscopy analysis without artifacts related to the formation of ice crystals. It has been shown that the Carbopol hydrogel has a hierarchical structure made of large spherical entities of a few micrometers in size packed together and composed of much smaller agglomerated microgel particles. In addition, fluorescence and electron microscopies have pointed out that the presence of polyol additives in the gel formulation favors the formation of more dense or jammed structure, probably through hydrogen bonding. (c) 2015 Wiley Periodicals, Inc.

The formation of bimolecular complexes on metal surfaces through interaction between a single chemisorbed chiral molecule and a single chemisorbed prochiral substrate molecule can be considered as a preorganization step toward chirality transfer. In the case of asymmetric hydrogenation on chirally modified platinum catalysts, the metal surface dissociates H-2 and provides atomic hydrogen for the desymmetrization step. Along the reaction path, the combined chemisorption and intermolecular interactions in the assembly formed between the modifier and the substrate determine which enantiomer is formed in excess. In this study, we use DFT calculations and STM measurements to describe chemisorption and intermolecular interactions in isolable structures formed between single ketopantolactone and single (R)-1-(1-naphthyl)ethylamine molecules on Pt(111). The study reveals several distinct complexation geometries at the sub-molecular level as well as the stereodirecting forces operating in the most abundant bimolecular assemblies. The comparison of theoretical and experimental data strongly suggests that partial hydrogenation of KPL occurs under the experimental conditions and that some of the most abundant complexes are formed by the hydroxy intermediate.

Coal miners are commonly exposed to coal dust (CD) and polycyclic aromatic hydrocarbons (PAHs). The CD originates within the mine, whereas the PAHs are components of occupational and avocational exposures such as diesel engine exhaust and cigarette smoke. The CD exposure can cause coal workers’ pneumoconiosis, a disease of coal miners characterized by the aggregation of dust-laden macrophages near the respiratory bronchioles to form structures known as macules. Inflammation is a consistent feature of the pulmonary response to respirable CD (Ghanem et al. 2004; Rom et al. 1987). Although chronic inflammation is increasingly believed to play a role in carcinogenesis in many tissues (Marx 2004), the role of particle-induced inflammation in pulmonary carcinogenesis, the influence of particle-induced inflammation on the metabolism of PAHs and other known carcinogens, and the histopathologic alterations produced by combined exposure to CD and PAHs remain incompletely investigated. PAHs are metabolized to reactive intermediates by cytochrome P450 1 (CYP1) gene products. Recently, our laboratory has demonstrated that respirable CD inhibits PAH-induced CYP1A1 activity in the lung of rats. The down-regulation of CYP1A1 induction was associated with inflammation (Ghanem et al. 2004). This information suggests that CD may modify the metabolism of PAHs in the lung. However, molecular changes that are associated with CD exposure and resulting pulmonary inflammation and down-regulation of CYP1A1 induction have not yet been identified. In an experimental model of another pneumoconiosis, silicosis, caspase inhibition with resulting apoptosis down-regulation reduces silica-induced inflammation (Borges et al. 2002). Caspases play an important role in both the intrinsic and extrinsic apoptotic pathways (Droin and Green 2004), making their inhibition an elegant tool for investigating the overall role of caspase-dependent apoptosis in the pneumoconioses (Borges et al. 2002). Because apoptosis is believed to play an essential role in the inflammation associated with one pneumoconiosis, acute silicosis, and because inflammation increased as CYP1A1 activity decreased in the rat model of coal workers’ pneumoconiosis (Ghanem et al. 2004), we investigated the hypothesis that apoptosis plays a critical role in lung injury and down-regulation of CYP1A1 induction in mixed exposures to CD and the model PAH β-naphthoflavone (BNF).

The associations of several copper extractants: hydroxyoximes, amides of pyridine carboxilic acids, etc., as a consequence of intramolecular interactions and with various oxygen containing modifiers are described. The various associations of these copper extractants change the active concentration of the extractant and blocks its effectiveness. Some of the structures of such associations are also described.Se describen las asociaciones que presentan algunos agentes de extracción del cobre: hidroxioximas, amidas de ácidos piridincarboxílicos, etc., como consecuencia de interacciones intramoleculares y cuando la fase orgánica contiene, además, componentes orgánicos (modificadores) con átomos de oxígeno en su molécula. Como consecuencia de estas asociaciones cambia la concentración de la especie activa del agente de extracción disminuyendo su efectividad. Se describen algunas de las estructuras de estas asociaciones.

The direct enantiomeric separation of mianserin and 6-azamianserin and some of their derivatives, respectively, by means of HPLC using two different chiral selectors was investigated. For the cellulose-based Chiralcel OD column, a strong dependence of be lipophilicity of the compounds tested on the retention behaviour was observed. To some extent, this was also found for the enantiomeric separation on the amylose-based Chiralpak AD column. In some cases a complementary behaviour of these two phases was observed: racemic mixtures that could not be separated by one column could be resolved by the other one. (C) 1998 Elsevier Science Ltd.

12th National Spectroscopy Congress -- MAY 18-22, 2011 -- -- Antalya, TURKEY, WOS: 000303588400002, Cadmium atomization on W, Ru, and W + Ru modifier-coated platforms and pyrolytic graphite-coated platforms with and without W, Ru, W + Ru, and Pd + Mg modifier solutions was obtained by electrothermal atomic absorption spectrometry (ETAAS). Surface morphologies of coated and uncoated platforms were investigated by scanning electron microscopy to show the evidence of coating. Pyrolysis, peak appearance, and atomization temperatures of Cd with or without coated platforms and modifier solutions were obtained. The activation energies and frequency factors of Cd atomization were found and evaluated. Results obtained were comprehensively compared with each other and published values., Gazi University (BAP)Gazi University [41/2009 - 06], The financial supports of Gazi University Research Fund (BAP No: 41/2009 - 06) are gratefully acknowledged.

This article reports on the dyeing of wool using an enzymatic system comprising laccase; dye precursor, 2,5-diaminobenzenesulfonic acid; and dye modifiers, catechol and resorcinol. Enzymatic dyeing was performed as a batchwise process at the temperature and pH of maximum enzyme activity. The effects of the process variables reaction time, enzyme, and modifier concentration on fabric color were studied, according to an appropriate experimental design. Different hues and depths of shades could be achieved by varying the concentration of the modifiers and the time of laccase treatment. The duration of the enzymatic reaction appeared to be the most important factor in the dyeing process. Thus, the dyeing process, performed at low temperature and mild pH, was advantageous in terms of reduced enzyme and chemical dosage.

The study results of the oxide composition influence on the glaze properties with temperature formation 1150-1200 ° C are presented. The mathematical dependence of coating gloss, whiteness, thermal stability of coatings on the content of glass-forming, modifying and mufflers components are fitted. The composition of unfritted opaque glazes is developed and the properties and structure and phase composition characteristics of coatings, obtained from using them are defined.