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Discriminating cereal and pseudocereal species using a binary system of GC-MS data - A pattern recognition approach
No full textVarious cultivars of different cereal and pseudocereal species (9 wheat, 8 barley, 1 rye, 3 oat, 2 triticale, 3 spelt, 12 corn, 3 amaranth and 9 buckwheat cultivar samples) were milled into flour, extracted using n-hexane, derivatized with trimethylsulfonium hydroxide solution, and subjected to GC-MS analysis. Fatty acid methyl esters and non-saponifiable compounds (phytosterols, alpha-tocopherol and squalene) were identified by comparing mass spectra with the Wiley MS library. A binary system was applied in further data processing: the presence or the absence of a particular lipid component in each sample was coded with either (1) or (0). Major lipid components that were present in all analyzed flour samples were removed from further data analysis, leaving only those that represent a good pattern to differentiate the flour samples according to corresponding cereal/pseudocereal species. Pattern recognition tools (cluster analysis and principal component analysis) were applied to visualize groupings and separations among the samples. The presented approach enables the rapid differentiation of flour samples made from various cereal/pseudocereal species according to their botanical origin and gluten content, thereby, successfully avoiding exact quantitative determinations
Experimental and mechanistic study of the inhibitory effects by phenolics on the oscillations of the OrbA n-Epstein Reaction
No full textThe system KSCN-H2O2-CuSO4-NaOH, also known as the OrbA n-Epstein oscillatory reaction, is exposed to external perturbations by several phenolic compounds: catechol, resorcinol, hydroquinone, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, caffeic acid, and ferulic acid. As a result of the performed perturbation in most examined cases, oscillations have been inhibited for some characteristic time, and resumed afterwards. The evaluated inhibition time is typical for each substance and strongly dependent on its concentration. The chemical mechanism of the interaction between the OrbA n-Epstein system and phenolic compounds is briefly discussed. Numerical simulations are performed using the original OrbA n-Epstein model with 30 reactions, extended by three reactions describing the interaction with inhibitory substances. The rate constants of three added reactions are adjusted to fit experimental inhibition times, and compared among used compounds. The observed effects are discussed further in relation with the bond dissociation enthalpy theory. Unlike other tested compounds, 2,5-dihydroxybenzoic acid remains off from predicted order of activity
Laser-based optical techniques for the detection of chemical agents
No full textAmong numerous existing and developing techniques for the detection of air pollution, laser-based optical methods (LBM) are possibly the most promising ones. Unique sensing capabilities of LBM include high speed of analysis, high selectivity, sensitivity and accuracy, low detection limits, and remote detection. This paper gives a brief review of several laser-based systems for optical sensing of gas-phase chemical agents: laser intra-cavity, photoacoustic and laser-induced breakdown spectroscopy, and remote sensing based on differential absorption. For each method, a brief description of the principles of operation is given, and its analytical capabilities are outlined
Floating Photocatalyst Based on Poly(ε-caprolactone) Foam and TiO2 Nanoparticles for Removal of Textile Dyes
No full textThis study discusses a novel approach for fabrication of floating photocatalyst which can be efficiently exploited for photodegradation of dyes in aqueous solutions. A fabrication of the floating photocatalyst consisted of two steps: transformation of the poly(ε-caprolactone) beads (PCLb) into poly(ε-caprolactone) foam (PCLf) with porous structure in supercritical carbon-dioxide and subsequent loading of PCLf with TiO2 nanoparticles (NPs). Morphological characterization of the PCLf before and after TiO2 NPs loading was carried out by FESEM. The presence of titanium on the surface and inside the PCLf was detected by EDX. Photocatalytical activity of the floating photocatalyst was investigated in aqueous solution of textile dyes C.I. Acid Orange 7 (AO7) and C.I. Basic Yellow 28 (BY28) which were exposed to lamp that simulates the sun light. In addition to sustainable floatability for a long period of time, developed floating photocatalyst exhibited high rate of photodegradation since the complete discoloration of AO7 and BY28 solutions and photocatalysts alone occurred after 300 and 180 min of illumination, respectively. Its photocatalytic activity was preserved after three repeated photodegradation cycles with unchanged chemical structure that was confirmed by FTIR analysis
Biodegradation behavior of textiles impregnated with Ag and TiO2 nanoparticles in soil
No full textIncreasing global consumption of textile goods poses serious environmental problems that are present throughout the products life-cycles. With a trend of Fast Fashion, clothes became consuming goods that are discarded in huge amounts into landfills where they rot generating undesirable gases which contribute to environmental pollution and greenhouse effect. A large-scale centralized composting is a possible alternative to harmful landfilling. It is well known that different textile fibers exhibit diverse biodegradation behavior. Unlike most of the synthetic fibers, natural and particularly cellulosic fibers are prone to biodegradation. However, the finishing and thus, the presence of different chemicals on fiber surfaces may affect their biodegradation performance. Recent progress in the production of textiles impregnated with different metal and metal oxide nanoparticles is more oriented toward end-use achievements than on their environmental and health safety impacts. Despite the urgency to establish their environmental risk assessment, there are only few papers dealing with biodegradation behavior of such textile nanocomposites under terrestrial conditions. Therefore, this chapter is aimed to provide an insight into these results and to stress the necessity of extended research in this field taking into consideration that various characteristics of nanoparticles are relevant for their biodegradation behavior
Molecular Assemblies of a Series of Mixed Tetravalent Uranium and Trivalent Lanthanide Complexes Associated with the Dipicolinate Ligand, in Aqueous Medium
No full textThe investigations of the chemical system involving tetravalent uranium associated with trivalent lanthanides (La, Ce, Nd, Sm Er, Lu) and dipicolinic acid (H(2)dpa) led to the identification of six distinct types of heterometallic coordination complexes (I-VI). These compounds, obtained at room temperature from aqueous solution, have been characterized by single crystal X-ray diffraction. They consist of tris-chelated dipicolinate uranium subunits {U(dpa)(3)} interacting with poly oxo/aquo or mixed polyoxo/aquo chelated dipicolinate lanthanide subunits (LnO(1-3)(H(2)0)(5-8) or Ln(dpa)O0-3(H20)(4-6)) in different arrangements. Complex I (La, Ce) exhibits the assembly of molecular dinudear [ULn] and [ULnU] trinuclear units, with a linkage between U and Ln via bidentate carboxylate groups of the dipicolinate molecules. The same carboxylate bridging connection mode creates a linear chainlike coordination polymer in complex II (La, Ce), with a strict alternating U Ln sequence. Complex III (Ce, Nd) contains an octanuclear motif based on six-ring [Ln(4)U(2)] decorated by two peripheral {U(dpa)(3)} subunits, resulting in a [Ln(4)U(4)] entity, through carboxylate bridges. Complex IV crystallizes by using a wide series of lanthanide cations (Nd, Sm-Tb) and consists of a simple assembly of discrete {U(dpa)(3)} subunits with {Ln(Hdpa)(H2O)(6)}. The complex V (Tb Er) is composed of a hexanudear motif based on four-ring [U(2)Ln(2)] with two peripheral {U(dpa)(3)} subunits (final complex [U(4)Ln(2)]). The last complex (VI) occurs with the lutetium and is built up from a dinudear unit [ULu] connected through one carboxylate group. Thermal decomposition of samples of complexes II IV has been analyzed by thermogravimetry and in situ XRD. The luminescence spectrum of the europium-based complex IV has been measured
Trametes versicolor ethanol extract, a promising candidate for health-promoting food supplement
No full textThis study aimed to estimate antiradical, antioxidant (AO) and cytotoxic activities of the fungus Trametes versicolor ethanol fruiting body extract. The extract was found to effectively scavenge both O-2(center dot-) and NO center dot (29.62 and 52.48g/mL, respectively). It also showed a good AO activity in the polarographic HPMC assay (950%/mL). p-Hydroxybenzoic acid may be one of the responsible compounds for the afore-mentioned activities. The same extract also exhibited a concentration-dependent cytotoxicity against MCF-7 and HepG2 tumour cell lines reaching IC50 values of 123.51 and 134.29g/mL, respectively with no cytotoxic activity against normal MRC-5 cells. Gentisic, syringic and protocatechuic acids may be among the bioactive principles for the observed cytotoxicity. Taken all together, T. versicolor ethanol extract can be considered as a promising candidate for development of health promoting food supplement. [GRAPHICS]
Open-circuit potential of a Pt electrode immersed in different aqueous solutions
No full textThe aim of this study is to investigate the multi-day behavior of the electromotive force (EMF) between Pt and reference Ag/AgCl, KClsat. electrodes immersed in various aqueous systems (deionized water, 1 x 10(-3) M H2SO4 solution and 0.15 M KCl solution) at 32 A degrees C and also at ambient temperature, without oxygen removal and redox species introduction. The control test of EMF behavior in the presence of redox species was performed with cyanide complexes of Fe2+ and Fe3+ ions at ambient temperature. In experiments with deionized water, systems were protected against the influence of daylight and static electricity. The results have shown diurnal oscillations of EMF in all investigated systems with amplitudes in the range ae 1 to 25 mV depending on applied experimental conditions. EMF oscillations in deionized water were independent on the applied temperature and yielded amplitudes of 15-25 mV in daylight regime, and only a few mV when protected from its influence. The effect of electrostatic electricity was not observed. Diurnal EMF oscillations with the amplitudes 5 mV were observed individually in 0.15 M KCl solution, redox system and after 4 days of investigation in H2SO4 solution. Results presented in this work pointed out that the behavior of Pt-oxygen electrode is specific and very complex, even in the simplest system such as deionized water. To investigate the origin of the observed EMF oscillations and the application of Pt-oxygen electrode in in situ multi-day dynamics studies under open-circuit potential condition, additional theoretical and experimental methods and particularly electrochemical ones, must be applied
Influence of various concentrations of 24-epibrassinolide on the kinetic parameters during isothermal dehydration of two maize hybrids
No full text24-epibrassinolide (24-EBL) is plant steroid hormone that can regulate several physiological effects in plants, including promotion of cell growth and induction of heat stress tolerance. The purpose of this work is to investigate the influence of various concentrations of 24-EBL on the dehydration mechanism of seedlings of two maize hybrids (ZP434 and ZP704). Control and treated samples were subjected to isothermal conditions for dehydration processes. The effects of carbohydrates and mineral contents on the possible changes in the dehydration mechanism (from kinetics standpoint) were investigated. Comparing control samples to samples treated with 24-EBL, it was found that different dehydration mechanisms exist The differences arise from the influence of 24-EBL, that causes a significant increase of phosphorus values for ZP704, whilst the reverse was identified for ZP434. It was assumed that the plumule sensitivity to dehydration stress originates from the interaction of water with primary amino groups as cations in polyamines, for lower concentrations of 24-EBL. It was found that the temperature variation (105-130 degrees C) leads to situations where trehalose does not arrive fast enough to "replace the water", because its handicap to binds (by hydrogen bonds) to biomolecules instead of water. It was found that 24-EBL cause changes of carbohydrates properties, which are important for the defense mechanism from environmental stresses