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991.
A fast, reliable and precise method for the determination of Ba, Zr, Th, U, La, Ce, Eu, Hf and Gd in leaching solutions containing up to 1 mol/L FeCl3 by inductively coupled plasma-atomic emission spectrometry (ICP-AES) was described. Liquid-liquid extraction with diethyl ether was applied for selective and quantitative extraction of the iron with a decontamination factor of 65000. The study has enabled the determination of rare earth elements, U, Th Ba, and Zr, from the solution with high iron content with detection limits in the range of 1-24 ng/ml and a precision of 0.9%-4.6 % relative standard deviation. The developed method was simple and was adopted for implementation in a glove box for handling radioactive materials. 相似文献
992.
Karin Sandin Lars Kloo Pernilla Nevsten Reine L. Wallenberg Lars-Fride Olsson 《Journal of materials science. Materials in medicine》2009,20(8):1677-1687
Pathological calcification is common among for instance dialysis patients, and this causes an increase in mortality risk.
An elevated serum phosphate concentration among those patients strongly correlates to this increase. In this work investigations
of the conditions, composition, crystallinity and morphology of in vitro calcification are performed and related to results
from in vivo studies. The study was performed under conditions mimicking physiological ones, i.e. a pH around 7.40, a temperature
of 37°C, an ionic strength of 150 mM and ion concentrations close to those in human serum including the effects of elevated
phosphate concentrations. The course of precipitation involves an initial precipitate that subsequently re-dissolves to give
another precipitate, in accordance with the well-known Ostwald ripening theory. The final bulk precipitate consists of a macroscopically
amorphous carbonated apatite. The amorphous apatite is formed from assemblies of spherical particles in the μm range, in turn
composed of nano-crystalline needles of about 10 × 100 nm. Even the initially formed precipitate, as well as a small amount
of precipitate that occurs on the liquid surface, consist of a carbonated calcium phosphate. The in vitro observed carbonated
apatite bears strong resemblance to in vivo cardiovascular calcification known from literature. 相似文献
993.
Anita Solbrand Karin Keis Sven Sdergren Henrik Lindstrm Sten-Eric Lindquist Anders Hagfeldt 《Solar Energy Materials & Solar Cells》2000,60(2)
The charge transport in nanoporous ZnO was studied by laser flash induced photocurrent transients. The results are discussed using a diffusion model and compared with previous results on TiO2. The charge transport was highly dependent on the potential giving apparent diffusion coefficients for the electron ranging from 1×10−4 to 1×10−6 cm2/s with an applied bias of +100 and +300 mV vs. Ag/AgCl in ethanol, respectively. The electrolyte was 0.5 M LiClO4 in ethanol. The potential dependence was much more pronounced for ZnO than for TiO2. The charge transport was also dependent on the electrolyte giving a linear dependence between the conductivity of the electrolyte and the apparent electronic diffusion coefficient. The dependence of the light intensity was also studied. Intensity-dependent losses were observed. 相似文献
994.
Simona Strnad Karin Stana‐Kleinschek Lidija Tuek Volker Ribitsch Carsten Werner Tatjana Kree 《大分子材料与工程》2002,287(4):296-305
Fine structure, surface properties (electrokinetic properties) and the accessibility of free adsorption groups determine the sorption behavior of fiber‐forming polymers. The fine structure of such polymers can be explained using a two‐phase model, composed of alternating crystalline and amorphous regions. Different treatments (heat, solutions, ...…) used in fiber production or finishing processes change the fine structure and surface morphology, causing differences in the accessibility of adsorption places. Distinctions in the sorption capacity of modified polymers occur in this manner. In this paper we have carried out an analysis (using PA 6 fibers as an example) of the interdependence between fiber crystalline structure (density determination and X‐ray analysis), surface morphology (using AFM), their electrokinetic character (streaming potential measurements) and their absorption properties (iodine sorption value determination). The structure and adsorption abilities of the PA 6 fibers were modified by annealing in vacuum and treatment in phenol solution. The results show that the modifications of the fibers' fine structure cause changes in both their surface morphology and electrokinetic properties. All these changes are reflected in the different fiber absorption properties. A well‐oriented fibril structure toward the fiber axis could be observed on the surface of the raw sample. Following annealing in a vacuum or treatment in phenol solution the surface fibrils joined together and built up wider fibril bounds with hollow places between them. These surface morphology changes are reflected in the different ZP values in plateau. They can be increased by simultaneous decreasing of the adsorption potential values (Φ, Φ) and the iodine sorption values. 相似文献
995.
996.
Karin J Larsson Ingrid K Undeland 《Journal of the science of food and agriculture》2010,90(14):2531-2540
BACKGROUND: Little is known about the relation between haemoglobin (Hb)‐mediated lipid and protein oxidation in muscle foods and how these two reactions can be inhibited by naturally occurring antioxidants. This study was aimed at evaluating (1) lipid oxidation and protein oxidation induced by 20 µmol L?1 Hb during chilled and frozen storage of washed cod mince and (2) the efficiency of 10–1000 ppm (0.063–6.3 mmol L?1) caffeic acid in preventing these reactions. RESULTS: Addition of 20 µmol L?1 Hb increased peroxide value (PV), rancid odour, protein carbonylation, protein insolubilisation, redness loss and α‐tocopherol loss in ice‐stored washed cod mince. Since both lipid and protein oxidation developed at the same time, it was not possible to conclude which reaction initiated the other. All studied reactions were efficiently inhibited by ≥ 50 ppm caffeic acid, which could be a result of α‐tocopherol regeneration, general radical scavenging, reduced formation of oxidised Hb forms and/or conformational changes in Hb structure. During frozen storage the only clear effect of Hb was increased PV, and here caffeic acid was less efficient as an antioxidant. CONCLUSION: Hb‐induced lipid and protein oxidation occurred quickly in ice‐stored washed cod mince, and the two reactions could not be separated in time. During frozen storage, Hb caused only limited lipid oxidation. Caffeic acid (≥50 ppm) was an efficient antioxidant during ice storage. Copyright © 2010 Society of Chemical Industry 相似文献
997.
ABSTRACT: This study compared myoglobin (Mb) oxidation in lipid-free model systems containing iron and Type I (radical quenching) or Type II (metal chelating) antioxidants. Oxidation was measured as loss of oxymyoglobin (MbO2 ) during 0 to 24 h holding at 22 °C. Sodium tripolyphosphate (STPP) demonstrated iron-binding ability at all concentrations tested (88% and 21% added iron bound at 1 and 0.05 mg/mL, respectively). Iron chelation was observed for phytic acid only at the highest concentration (9.5% bound at 1 mg/mL phytate). Neither Type I antioxidant (rosmarinate or eugenol) demonstrated any iron chelating ability (<0.5% bound). In presence of iron, Type I antioxidants had a significant ( P < 0.05) prooxidant effect (54.7% retention of MbO2 in control, 9.5% and 37.5% retention in rosmarinate and eugenol samples, respectively). The Type II antioxidants (STPP and phytate) were more effective inhibitors ( P < 0.05) of Mb oxidation than Type I antioxidants, (68.7% and 61.1% for STPP and phytate, respectively). Type I antioxidants were capable of rapid reduction of ferric iron to the ferrous form, as measured by the ferrozine assay. This strong reducing ability accounted for the prooxidant effects of rosmarinic acid and eugenol, since ferrous iron is the form associated with generation of oxygen radicals, and subsequent Mb oxidation. Type II antioxidants chelated and thus prevented the oxidizing effect of added ferrous iron. Mb oxidation can proceed rapidly (within 15 min) in the presence of iron and the absence of lipid, especially if reducing compounds such as rosmarinic acid or eugenol are also present to maintain iron in an active ferrous form. 相似文献
998.
Marsh J Rigby N Wellner K Reese G Knulst A Akkerdaas J van Ree R Radauer C Lovegrove A Sancho A Mills C Vieths S Hoffmann-Sommergruber K Shewry PR 《Molecular nutrition & food research》2008,52(Z2):S272-S285
Peanut is a major cause of type 1 hypersensitive reactions including anaphylaxis. This results from the presence of a number of protein allergens, six of which are being studied as part of the EU FP6 EuroPrevall programme. These are Ara h 1 (7S globulin), Ara h 2, Ara h 6 (2S albumins), Ara h 3/4 (11S globulins) and Ara h 8 (Bet v 1 homologue). Methods for the purification of Ara h 1, Ara h 3/4, Ara h 2 and Ara h 6 from peanut seeds and for the production of recombinant Ara h 8 in Escherichia coli are described with spectroscopic analyses being used to confirm that they are authentically folded. N-terminal sequencing of the proteins purified from peanut seeds also revealed details of the differences between isoforms and their generation by proteolytic processing within the seed. Preliminary IgE binding studies of the purified allergens confirmed that they retained their immunological properties indicating their suitability for use in allergy diagnosis. 相似文献
999.
NanoTIO2 (UV-Titan) does not induce ESTR mutations in the germline of prenatally exposed female mice
Anne Mette Zenner Boisen Thomas Shipley Petra Jackson Karin S?rig Hougaard H?kan Wallin Carole L Yauk Ulla Vogel 《Particle and fibre toxicology》2012,9(1):1-5
Background
Particulate air pollution has been linked to an increased risk of cardiovascular disease and cancer. Animal studies have shown that inhalation of air particulates induces mutations in the male germline. Expanded simple tandem repeat (ESTR) loci in mice are sensitive markers of mutagenic effects on male germ cells resulting from environmental exposures; however, female germ cells have received little attention. Oocytes may be vulnerable during stages of active cell division (e.g., during fetal development). Accordingly, an increase in germline ESTR mutations in female mice prenatally exposed to radiation has previously been reported. Here we investigate the effects of nanoparticles on the female germline. Since pulmonary exposure to nanosized titanium dioxide (nanoTiO2) produces a long-lasting inflammatory response in mice, it was chosen for the present study.Findings
Pregnant C57BL/6 mice were exposed by whole-body inhalation to the nanoTiO2 UV-Titan L181 (~42.4?mg UV-Titan/m3) or filtered clean air on gestation days (GD) 8?C18. Female C57BL/6?F1 offspring were raised to maturity and mated with unexposed CBA males. The F2 descendents were collected and ESTR germline mutation rates in this generation were estimated from full pedigrees (mother, father, offspring) of F1 female mice (192 UV-Titan-exposed F2 offspring and 164?F2 controls). ESTR mutation rates of 0.029 (maternal allele) and 0.047 (paternal allele) in UV-Titan-exposed F2 offspring were not statistically different from those of F2 controls: 0.037 (maternal allele) and 0.061 (paternal allele).Conclusions
We found no evidence for increased ESTR mutation rates in F1 females exposed in utero to UV-Titan nanoparticles from GD8-18 relative to control females. 相似文献1000.