Analysis of additive metals in fuel and emission aerosols of diesel vehicles with and without particle traps

Fuel additives used in particle traps have to comply with environmental directives and should not support the formation of additional toxic substances. The emission of metal additives from diesel engines with downstream particle traps has been studied. Aspects of the optimisation of sampling procedure, sample preparation and analysis are described. Exemplary results in form of a mass balance calculation are presented. The results demonstrate the high retention rate of the studied filter system but also possible deposition of additive metals in the engin

Translocation of silver nanoparticles in the ex vivo human placenta perfusion model characterized by single particle ICP-MS

With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs). AgNPs and ionic Ag were detected in the fetal circulation in low but not negligible amounts. Slightly higher Ag translocation across the placental barrier for perfusion with AgPEG NPs and higher AgNP accumulation in placental tissue for perfusion with AgCOONa NPs were observed. Since these AgNPs are soluble in water, we tried to distinguish between the translocation of dissolved and particulate Ag. Perfusion with AgNO3 revealed the formation of Ag containing NPs in both circulations over time, of which the amount and their size in the fetal circulation were comparable to those from perfusion experiments with both AgNP types. Although we were not able to clarify whether intact AgNPs and/or Ag precipitates from dissolved Ag cross the placental barrier, our study highlights that uptake of Ag ions and/or dissolution of AgNPs in the tissue followed by re-precipitation in the fetal circulation needs to be considered as an important pathway in studies of AgNP translocation across biological barriers

Translocation of silver nanoparticles in the ex vivo human placenta perfusion model characterized by single particle ICP-MS

With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs). AgNPs and ionic Ag were detected in the fetal circulation in low but not negligible amounts. Slightly higher Ag translocation across the placental barrier for perfusion with AgPEG NPs and higher AgNP accumulation in placental tissue for perfusion with AgCOONa NPs were observed. Since these AgNPs are soluble in water, we tried to distinguish between the translocation of dissolved and particulate Ag. Perfusion with AgNO3 revealed the formation of Ag containing NPs in both circulations over time, of which the amount and their size in the fetal circulation were comparable to those from perfusion experiments with both AgNP types. Although we were not able to clarify whether intact AgNPs and/or Ag precipitates from dissolved Ag cross the placental barrier, our study highlights that uptake of Ag ions and/or dissolution of AgNPs in the tissue followed by re-precipitation in the fetal circulation needs to be considered as an important pathway in studies of AgNP translocation across biological barriers

Effects of Fuel Tracing on Nanoparticles from a Diesel Engine

Nanoparticles from a HD-Diesel engine and their composition were investigated in the present paper. Three variants of fuel additivities were applied to allow the balances of certain tracer-substances after the tests: 2% of additives-free lube oil; 2% of market lube oil with additive package and Fe-based regeneration additive (FBC) with 40 ppm Fe. The analysed SMPS particle size distributions indicated that by blending of the market lube oil to the fuel the combined effects of metals or metal oxides from the additive packages and of the heavy HC’s from the lube oil matrix contribute the most to the increase of nuclei mode. From the masses of Fe, Zn and Ca, which were introduced with the fuel, only parts were found as integral masses at all ELPI-stages – Fe 43.5%, Zn 36.6%, Ca 65.5%. The majority of mass of some metals, or metal oxides emissions on ELPI-stages (up to 80%) is in the size ranges below 100 nm

Synthesis and Characterization of hydrogarnet Ca3(AlxFe1 - x)2(SiO4)y(OH)4(3 - y).

International audienceC3AH6 is a stable phase in the CaO-Al2O3-H2O system at temperatures 20 °C and above. The presence of SiO2 results in the formation of C3AH6 and C-S-H phases at room temperature. At 110 °C crystalline C3ASyH2(3 − y) phases form. Two solid solutions: C3AH6-C3AS0.41H5.18 and C3AS0.84H4.32-C3AS3 are found with log Ks0 = − 20.50, − 25.35, − 26.70 and − 39.7 at 20 °C, respectively. In the CaO-Fe2O3-H2O system, only traces of C3FH6 and C4FH13 phases are formed due to the high stability of FH phase. The presence of silica leads between 20 and 110 °C to the formation of C3FS0.84H4.32 and C3FS1.34H3.32 phases with log Ks0 = − 32.50 and − 34.20 at 25 °C. No significant solid solution formation occurred between C3AH6 and C3FH6 end members, but between C3AS0.84H4.32 and C3FS0.84H4.32 solid solution formation is observed. The determined solubility products indicate that C3FS0.84H4.32 is the most stable iron-containing phase in hydrated Portland cements

Stability of Monosulfate in the Presence of Iron

International audienceMonosulfate (3CaO*(AlxFe1x)2O3*CaSO4*12H2O) is an AFm phase that can be formed during the hydration of cement. Fe-containing monosulfate and (Al,Fe) mixed monosulfate were synthesized and characterized. Fe-monosulfate is composed of a positively charged main layer [Ca2Fe(OH)6]+ and a negatively charged interlayer [1/2SO4*3H2O]−, crystallizes in the trigonal R 3 symmetry, and is isotypic with Al-monosulfate. The solubility product at 25°C was determined to be 31.57. The formation of solid solution due to Al-Fe substitution in the main layer structure of monosulfate was observed. Based on the evolution of the unit cell parameters and the thermodynamic investigations, a presence of solid solution from 0.0 to 0.45 Al/(Al + Fe) ratio and a miscibility gap in the range 0.45 < Al/(Al + Fe) ratio <0.95 is suggested

Cytotoxic effects of nanosilver are highly dependent on the chloride concentration and the presence of organic compounds in the cell culture media

Abstract Background Nanosilver shows great promise for use in industrial, consumer or medical products because of its antimicrobial properties. However, the underlying mechanisms of the effects of silver nanoparticles on human cells are still controversial. Therefore, in the present study the influence of the chloride concentration and different serum content of culture media on the cytotoxic effects of nanosilver was systematically evaluated. Results Our results show that nanosilver toxicity was strongly affected by the composition of the culture media. The chloride concentration, as well as the carbon content affected the silver agglomeration and the complex formation. But also the dissolution of nanosilver and the availability of free silver ions (Ag + ) were severely affected by the compositions of the culture media. Cells, only exposed to silver particles in suspension and dissolved silver complexes, did not show any effects under all conditions. Nanosilver agglomerates and silver complexes were not very soluble. Thus, cells growing on the bottom of the culture dishes were exposed to sedimented nanosilver agglomerates and precipitated silver complexes. Locally, the concentration of silver on the cell surface was very high, much higher compared the silver concentration in the bulk solution. The cytotoxic effects of nanosilver are therefore a combination of precipitated silver complexes and organic silver compounds rather than free silver ions. Conclusions Silver coatings are used in health care products due to their bacteriostatic or antibacterial properties. The assessment of the toxicity of a certain compound is mostly done using in vitro assays. Therefore, cytotoxicity studies of nanosilver using human cell cultures have to be undertaken under well controlled and understood cultivations conditions in order to improve the compatibility of different studies. Especially when eukaryotic versus prokaryotic systems are compared for the evaluation of the use of nanosilver as antibacterial coatings for implants in order to prevent bacterial colonization

High-precision mapping of fluorine and lithium in energy materials by means of laser-induced XUV spectroscopy (LIXS)

Laser-induced breakdown spectroscopy (LIBS) is a well-established elemental analysis method, thanks to negligible sample preparation, rapid analysis, and a spatially resolved sensitivity down to trace level, in any kind of matrix. State-of-the-art LIBS is operated in the optical spectral range (UV-VIS). Unfortunately, the measurement precision is limited by the moderate stability and repeatability of the plasma emission. The detection and sensitivity to crucial elements such as light elements and halogens are also limited. This is particularly critical for inhomogeneous materials where signal fluctuation is related to the spatial elemental distribution. To overcome these disadvantages specific, LIBS techniques arrangement are often required. Laser-induced XUV Spectroscopy (LIXS) has some intrinsic advantages for overcoming some of the above mentioned limitations and it can support the spectroscopic information collected in the UV-VIS range.ISSN:0584-854