439 research outputs found

    Structural stability and local electronic properties of some EC synthesized magnetite nanopowders

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    Structural and electronic properties, oxidation and aging effect of electrochemically (EC) synthesized magnetite nanopowders (NPs) are studied by means of X–ray diffraction (XRD), X–ray absorption fine structure (XAFS) and X–ray magnetic circular dichroism (XMCD). The obtained results enabled to get a direct insight into the structure and electronic properties of Fe immediate surrounding and to elucidate the influence of preparation conditions on stoichiometry of NPs and their stability in ambient conditions. All investigated NPs are produced as non–stoichiometric Fe3δ_{3−δ}O4_4 oxide phases, with the lattice constant and the Fe2+^{2+}/Fe3+^{3+} ratio both in–between the values for bulk maghemite and magnetite. NPs synthesized under smaller current density (J = 200 mA/dm2^2) are more magnetite–alike, whereas larger current density (J = 1000 mA/dm2^2) has led to formation of NPs closer to maghemite. Oxidation of magnetite–like NPs is slower, although in the course of time particles agglomerate and oxide penetrates into the core. Maghemite–like NPs oxidize much faster and the oxide layer which is confined close to the particles' surface protects the core from further oxidation. In all NPs the fist coordination around Fe is pretty stable against both temperature and oxidation process. The temperature change from 293 K to 20 K considerably affects the second coordination around Fe, which is most likely a consequence of the Verwey transition present in all investigated samples

    Techno-functional, textural and sensorial properties of frankfurters as affected by the addition of bee pollen powder

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    The objective of this study was to determine whether the addition of different pollen powder concentrations (0.5; 1.0 and 1.5 g/100 g) had an influence on techno-functional, textural and sensorial traits of frankfurters. Examining the techno-functional characteristics of pollen, a conclusion was reached that the higher the concentration, the higher the emulsification and better techno-functional properties. Also, FTIR-ATR analysis has shown that specific pollen molecules provided good emulsifying properties of sausages. On the other hand, sensory analysis showed that sausages with the addition of 1.0% and 1.5% of pollen powder have a more pronounced floral odor. Warner-Bratzler shear force test has shown that the incorporation of pollen caused a more stable product throughout sixty days of storage than the control sample. It could be explained by the formation of more protein-protein interactions due to the addition of non-meat proteins in the formulation of frankfurters and obtaining a more stable product than the control one. All things considered, it can be concluded that pollen exhibits good techno-functional properties and could be utilized in the formulation of frankfurters with improved and steady techno-functional properties during two months of refrigerated storage

    Changes in chemical attributes during ripening of traditional fermented sausage, "Pirot ironed"

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    "Pirot ironed" is a traditional Serbian dry-fermented sausage manufactured in the southeast of Serbia. The changes in the chemical attributes of Pirot ironed sausage were followed during ripening. Samples were taken on the processing days 0, 7, 14, 21 and 28. Pirot ironed sausage was produced from the most valuable cuts of beef and chevon, without addition of starter cultures or fat tissues. Sausages were manufactured in a traditional drying/ripening chamber, where they were pressed every two days to acquire the typical flat form and to speed up the drying. The final water activity was 0.839. The lowest pH value recorded was 5.30 on the processing day 28. During ripening, the water content decreased significantly from 74.72% to 40.32%, while the protein and the fat amounts increased significantly from 19.12% to 45.79% and from 1.22% to 6.21%, respectively. Up to now, the properties of Pirot ironed sausage have not been recognized or published in scientific literature in spite of the long tradition and popularity of this meat product in Serbia

    Hadamard magnetization transfers achieve dramatic sensitivity enhancements in homonuclear multidimensional NMR correlations of labile sites in proteins, polysaccharides and nucleic acids

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    EXSY, TOCSY and NOESY lie at the foundation of homonuclear NMR experiments in organic and pharmaceutical chemistry, as well as in structural biology. Limited magnetization transfer efficiency is an intrinsic downside of these methods, particularly when targeting rapidly exchanging species such as labile protons ubiquitous in polysaccharides, sidechains and backbones of proteins, and in bases and sugars of nucleic acids: the fast decoherence imparted on these protons through solvent exchanges, greatly reduces their involvement in homonuclear correlation experiments. We have recently discussed how these decoherences can be visualized as an Anti-Zeno Effect, that can be harnessed to enhance the efficiency of homonuclear transfers within Looped PROjected SpectroscopY (L-PROSY) leading to 200-300% enhancements in NOESY and TOCSY cross-peaks for amide groups in biomolecules. This study demonstrates that even larger sensitivity gains per unit time, equivalent to reductions by several hundred-folds in the duration of experiments, can be achieved by looping inversion or using saturation procedures. In the ensuing experiments a priori selected frequencies are encoded according to Hadamard recipes, and subsequently resolved along the indirect dimension via linear combinations. Magnetization-transfer (MT) processes reminiscent of those occurring in CEST provide significant enhancements in the resulting cross-peaks, in only a fraction of acquisition time of a normal 2D experiment. The effectiveness of the ensuing three-way polarization transfer interplay between water, labile and non-labile protons was corroborated experimentally for proteins, homo-oligosaccharides and nucleic acids. In all cases, cross-peaks barely detectable in conventional 2D NMR counterparts, were measured ca. 10-fold faster and with 200-600% signal enhancements by the Hadamard MT counterparts

    The Use of Pork from Entire Male and Immunocastrated Pigs for Meat Products—An Overview with Recommendations

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    Due to the strong public initiative in Europe and increased regulator focus to mitigate pain, surgical castration of pigs is being gradually abandoned, while the importance of other sex categories like entire males (EM) and immunocastrates (IC) increases. Although beneficial for animal welfare and economics, their use also brings forward several quality problems. Besides the occurrence of boar taint in EM, these include excessive carcass leanness, softer fat, meat color and pH deviations, inferior water holding capacity and increased meat toughness. In this paper, the raw material differences between the male sex categories and their influence on product quality are reviewed, and possible solutions are presented. Using EM for dried or thermally processed products may result in lower processing yields and inferior sensory quality, which may partially be prevented by applying specific processing adaptations. Immunocastration is a viable solution, especially when prolonging the vaccination to slaughter interval. Low to medium levels of boar taint can be effectively managed in most of the meat products, applying procedures like cooking, microbial inoculation or masking (by spices and especially smoking), while highly tainted material can be valorized only by combining various methods and/or with dilution of the tainted meat.info:eu-repo/semantics/publishedVersio

    Survey of electronic properties and local structures around Fe in selected multinary chalcogenides

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    Paper presents detailed studies of local and electronic structure around Fe in Cd0.97Fe0.03Te, Cd0.98Fe0.02Te0.97Se0.03 and Cd0.99Fe0.01Te0.91S0.09 multinary chalcogenides by means of X ray absorption fine structure XAFS , X ray magnetic circular dichroism XMCD and electron paramagnetic resonance EPR measurements. In addition, electronic consequences of Fe incorporation into CdTe semiconductor host were studied by means of first principles calculations. In order to improve accuracy of the calculated total energies, the band gaps and the band edge positions, special attention is paid to the treatment of exchange correlation interaction and the description of highly localized Fe 3d states. Also, the Bader theory of the topological properties of the electron charge density is used to access details of the nature, strength and distribution of the next nearest neighbour bonds. Local and electronic structure around Fe in Cd0.97Fe0.03Te and Cd0.98Fe0.02Te0.97Se0.03 systems have been found to exhibit similar characteristics, since the first coordination sphere around Fe comprises four Te atoms located at approximately the same distance. In Cd0.99Fe0.01Te0.91S0.09 system, however, local bimodal distribution of distances has been revealed, with one Fe Te bond replaced with much shorter Fe S bond, resulting in much stronger crystal field. Along with the crystal field effect, the spin orbit interaction has proven to play decisive role in determining the nature of Fe doped CdTe systems. While the systems with higher Fe concentrations 25 at. are intrinsic insulators, in systems with only 3.125 at. Fe one spin channel contributes to the density of states at the Fermi level, which makes them suitable for spin selective electronic transport application

    Vitamin D in the general population of young adults with autism in the Faroe Islands

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    Vitamin D deficiency has been proposed as a possible risk factor for developing autism spectrum disorder (ASD). 25-Hydroxyvitamin D3 (25(OH)D3) levels were examined in a cross-sectional population-based study in the Faroe Islands. The case group consisting of a total population cohort of 40 individuals with ASD (aged 15–24 years) had significantly lower 25(OH)D3 than their 62 typically-developing siblings and their 77 parents, and also significantly lower than 40 healthy age and gender matched comparisons. There was a trend for males having lower 25(OH)D3 than females. Effects of age, month/season of birth, IQ, various subcategories of ASD and Autism Diagnostic Observation Schedule score were also investigated, however, no association was found. The very low 25(OH)D3 in the ASD group suggests some underlying pathogenic mechanism
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