FEBUKO and MODMEP: Field measurements and modelling of aerosol and cloud multiphase processes

An overview of the two FEBUKO aerosol–cloud interaction field experiments in the Thüringer Wald (Germany) in October 2001 and 2002 and the corresponding modelling project MODMEP is given. Experimentally, a variety of measurement methods were deployed to probe the gas phase, particles and cloud droplets at three sites upwind, downwind and within an orographic cloud with special emphasis on the budgets and interconversions of organic gas and particle phase constituents. Out of a total of 14 sampling periods within 30 cloud events three events (EI, EII and EIII) are selected for detailed analysis. At various occasions an impact of the cloud process on particle chemical composition such as on the organic compounds content, sulphate and nitrate and also on particle size distributions and particle mass is observed. Moreover, direct phase transfer of polar organic compound from the gas phase is found to be very important for the understanding of cloudwater composition. For the modelling side, a main result of the MODMEP project is the development of a cloud model, which combines a complex multiphase chemistry with detailed microphysics. Both components are described in a fine-resolved particle/drop spectrum. New numerical methods are developed for an efficient solution of the entire complex model. A further development of the CAPRAM mechanism has lead to a more detailed description of tropospheric aqueous phase organic chemistry. In parallel, effective tools for the reduction of highly complex reaction schemes are provided. Techniques are provided and tested which allow the description of complex multiphase chemistry and of detailed microphysics in multidimensional chemistry-transport models

Chemical reactivity and long-range transport potential of polycyclic aromatic hydrocarbons – a review

Polycyclic aromatic hydrocarbons (PAHs) are of considerable concern due to their well-recognised toxicity and especially due to the carcinogenic hazard which they present. PAHs are semi-volatile and therefore partition between vapour and condensed phases in the atmosphere and both the vapour and particulate forms undergo chemical reactions. This article briefly reviews the current understanding of vapour-particle partitioning of PAHs and the PAH deposition processes, and in greater detail, their chemical reactions. PAHs are reactive towards a number of atmospheric oxidants, most notably the hydroxyl radical, ozone, the nitrate radical (NO3) and nitrogen dioxide. Rate coefficient data are reviewed for reactions of lower molecular weight PAH vapour with these species as well as for heterogeneous reactions of higher molecular weight compounds. Whereas the data for reactions of the 2-3-ring PAH vapour are quite extensive and generally consistent, such data are mostly lacking for the 4-ring PAHs and the heterogeneous rate data (5 and more rings), which are dependent on the substrate type and reaction conditions, are less comprehensive. The atmospheric reactions of PAH lead to the formation of oxy and nitro derivatives, reviewed here, too. Finally, the capacity of PAHs for long range transport and the results of numerical model studies are described. Research needs are identified

Global fate and distribution of polycyclic aromatic hydrocarbons emitted from Europe and Russia, Atmos. Environ. 41 (2007) 8301-8315

The long-range atmospheric transport (LRT) of polycyclic aromatic hydrocarbons (PAHs) is not fully understood and has hardly been addressed by model studies. By model experiments the LRT of PAH emissions into air from Europe and Russia is studied testing several scenarios of gas–particle partitioning and degradability by reaction with ozone and the hydroxyl and nitrate radicals for two PAHs, benzo[a]pyrene (BAP) and fluoranthene (FLT). The model used is the atmosphere general circulation model ECHAM5 with a dynamic modal aerosol sub-model, HAM, ozone and sulfur species chemistry and bidirectional mass exchange on 2D marine (ocean surface mixed layer) and terrestrial surfaces (top soil layer and vegetation surfaces). After 5 years the substances are found to be mostly distributed to the soil compartment (64–97% as the global mean, varying with substance and season), which after 10 years is still filling; 1–5% are found in air and 2–33% in ocean. It is found that the lifetime and vertical distribution of the substances in the atmosphere and the LRT potential are all significantly influenced by the partitioning and degradation scenario. The total environmental burden is higher when sorption to organic matter and black carbon are considered to determine gas–particle partitioning rather than adsorption to the surface of particulate matter. The effect is þ20% for BAP but sevenfold for FLT. Concentrations in Arctic air are mostly underestimated by the model, which is partly explained by emissions not considered in the simulation. The comparison shows, however, that degradation of the sorbed BAP and FLT molecules should be significantly slower than the respective gaseous molecules and that absorptive partitioning is necessary to explain the LRT potential of FLT

Behaviour of hydrogen in Fe-Ni-C alloys

A particular cathodic charging technique was used to evaluate the behaviour of hydrogen on Fe-25.66Ni-0.31C alloy. This technique is based on the electrolysis of water injected in a molten salts bath. The electrolytic charging conditions were chosen as −2.05V/Ag and 300°C. The quantities of hydrogen extracted from specimens of different diameters after electrolysis over different durations were used to calculate both the substantial surface concentration (C-0=3cm(3) H-2/cm(3) metal) and the hydrogen concentration profiles in austenite. After quenching at −65°C, a linear relationship between the hydrogen concentration and the amount of retained austenite was determined. A critical concentration C-k=0.06 cm(3) H-2/cm(3) metal, initiated microcracks in martensite. The behaviour of hydrogen on austenite is discussed in terms of grain boundary and dislocation trapping

HIF-2a, but not HIF-1a, is essential for hypoxic induction of class IIIb-tubulin expression in human glioblastoma cells

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Mechanical study of instability of austenitic Fe-Ni-C alloys — Effect of hydrogen

The mechanical properties of different Fe-Ni-C alloys, in which Ni and C contents are correlated in order to ensure roughly equal Ms temperatures, are investigated considering three austenitic states: water-cooled (gamma), cathodically hydrogen charged at 300°C (gamma + 300°C/H-2), and heat-treated at 300°C (gamma + 300°C) for comparison. The true stress σ versus true strain are approximated by σ = K-1 + K-2 epsilon(1/2). Except for 0.006 wt %C, the fitting displays two or three domains of strain characterized by higher values of the slope K2 at high deformations. For carbon content beyond ≈ 0.2 wt% C this slope increase is due to strain induced martensite. As a consequence transformation induced plasticity (TRIP) effect, confined to medium carbon contents, is observed. At the same time the stress-strain diagrams exhibit instabilities in the form of serrated yieldings. The critical stress and strain of their onset is correlated to the number of Frank-Read sources (FRS) activated by the plastic flow. In the case of higher carbon alloys and higher strains, the increased slope K2 is thought to be due to another strengthening mechanism involving carbon atoms in the solid solution, associated with Portevin-Le Chatelier (PLC) effect. At low carbon content the effect of hydrogen in prior austenite is negligible, but at high contents the embrittlement and cracking of the strain induced martensite is immediate

Effects of betaIII-tubulin knockdown on the growth of glioblastoma cells and on the efficacy of chemotherapies

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Use of natural iron oxide as heterogeneous catalyst in photo-Fenton-like oxidation of chlorophenylurea herbicide in aqueous solution: Reaction monitoring and degradation pathways

SSCI-VIDE+CARE+HME:SRS:CGOInternational audienceThe photocatalytic degradation of 3-[3,4-(dichlorophenyl)-1-methoxy-1-methylurea] (Linuron), which is oneof phenylurea herbicides, has been studied using natural iron oxide(NIO) as a heterogeneous catalyst in the presence of H2O2 under variousconditions. The characterization of this catalyst revealed that NIO has amixed elemental composition and consists mainly of iron oxide(alpha-Fe2O3). This powder contains hematite as iron source and itsdissolution provides Fe3+ cations for the Fenton-like reaction insolution. The degradation rate was strongly influenced by pH, initialconcentrations of H2O2, amount of NIO particles and type of irradiation(artificial or natural sunlight). An initial Linuron concentration of4.0 x 10(-5) mol L-1 was completely degraded after 45 min under theoptimum conditions. The decrease of chemical oxygen demand (COD) as aresult of mineralization of the herbicide was observed i.e., 99.99% ofthe initial concentration of Linuron and over 80% of COD were removedafter 6 h under our experimental conditions. The degradation of Linuronis mainly due to the formation of hydroxyl radicals as confirmation bythe use of 2.0% of isopropanol as an HO center dot scavenger. Thedecomposition of Linuron gave eight main intermediate products, and adegradation mechanism is suggested on the basis of these identifiedintermediates. The use of NIO is interesting; because in addition to itscatalytic effect, its high density enables an easy solid-liquidseparation, making it a versatile material for environmentalapplications. (C) 2015 Elsevier B.V. All rights reserved

Effects of betaIII-tubulin knockdown on the growth of glioblastoma cells and on the efficacy of chemotherapies.

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The SWEET-HOME Project: Audio Technology in Smart Homes to improve Well-being and Reliance

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