Kinetics and Products of Air Plasma Induced Oxidation in Water of Imidacloprid and Thiamethoxam Treated Individually and in Mixture

Imidacloprid (I) and thiamethoxam (T) are widely used neonicotinoid insecticides with high persistence in the environment and thus included in the watch list of substances for European Union-wide monitoring reported in the Decision 2015/495/EU. In this work aqueous solutions of I, T and I + T were subjected to advanced oxidation by air plasma produced by negative DC corona discharges above the liquid surface. The oxidative degradation of each pollutant was investigated by monitoring the rate and the products of its decay when treated alone and in the presence of variable amounts of the other compound. The results show that both I and T are readily degraded and that mineralization can be achieved in this process, as proven by the measurement of the residual organic carbon and by the quantitative conversion of chlorine and sulfur into inorganic chloride and sulfate, respectively. The major organic intermediates formed during the complex stepwise oxidation of I and T were identified and monitored by HPLC\u2013MS/MS analysis. The results of kinetic studies show that both for I and T the reaction rate depends inversely on the insecticide initial concentration, that I and T have similar reactivities and that they do not interfere reciprocally in any specific way when treated in mixture at a total concentration of ca 1 7 10 124 M. Based on literature data and on previous results with the same reactor, it is reasonable to propose that the oxidation of I and T is initiated by the reaction with OH radicals

Assessing the exoproteome of marine bacteria, lesson from a RTX-toxin abundantly secreted by Phaeobacter strain DSM 17395.

[eng] Bacteria from the Roseobacter clade are abundant in surface marine ecosystems as over 10% of bacterial cells in the open ocean and 20% in coastal waters belong to this group. In order to document how these marine bacteria interact with their environment, we analyzed the exoproteome of Phaeobacter strain DSM 17395. We grew the strain in marine medium, collected the exoproteome and catalogued its content with high-throughput nanoLC-MS/MS shotgun proteomics. The major component represented 60% of the total protein content but was refractory to either classical proteomic identification or proteogenomics. We de novo sequenced this abundant protein with high-resolution tandem mass spectra which turned out being the 53 kDa RTX-toxin ZP_02147451. It comprised a peptidase M10 serralysin domain. We explained its recalcitrance to trypsin proteolysis and proteomic identification by its unusual low number of basic residues. We found this is a conserved trait in RTX-toxins from Roseobacter strains which probably explains their persistence in the harsh conditions around bacteria. Comprehensive analysis of exoproteomes from environmental bacteria should take into account this proteolytic recalcitrance

Proteomics meets blue biotechnology: A wealth of novelties and opportunities.

[eng] Blue biotechnology, in which aquatic environments provide the inspiration for various products such as food additives, aquaculture, biosensors, green chemistry, bioenergy, and pharmaceuticals, holds enormous promise. Large-scale efforts to sequence aquatic genomes and metagenomes, as well as campaigns to isolate new organisms and culture-based screenings, are helping to push the boundaries of known organisms. Mass spectrometry-based proteomics can complement 16S gene sequencing in the effort to discover new organisms of potential relevance to blue biotechnology by facilitating the rapid screening of microbial isolates and by providing in depth profiles of the proteomes and metaproteomes of marine organisms, both model cultivable isolates and, more recently, exotic non-cultivable species and communities. Proteomics has already contributed to blue biotechnology by identifying aquatic proteins with potential applications to food fermentation, the textile industry, and biomedical drug development. In this review, we discuss historical developments in blue biotechnology, the current limitations to the known marine biosphere, and the ways in which mass spectrometry can expand that knowledge. We further speculate about directions that research in blue biotechnology will take given current and near-future technological advancements in mass spectrometry

Innovative remotely-controlled bending device for thin silicon and germanium crystals

Steering of negatively charged particle beams below 1 GeV has demonstrated to be possible with thin bent silicon and germanium crystals. A newly designed mechanical holder was used for bending crystals, since it allows a remotely-controlled adjustment of crystal bending and compensation of unwanted torsion. Bent crystals were installed and tested at the MAMI Mainz MIcrotron to achieve steering of 0.855-GeV electrons at different bending radii. We report the description and characterization of the innovative bending device developed at INFN Laboratori Nazionali di Legnaro (LNL)

Steering of Sub-GeV electrons by ultrashort Si and Ge bent crystals

We report the observation of the steering of 855 MeV electrons by bent silicon and germanium crystals at the MAinzer MIkrotron. Crystals with 15 \uce\ubc m of length, bent along (111) planes, were exploited to investigate orientational coherent effects. By using a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature, it was possible to study the steering capability of planar channeling and volume reflection vs. the curvature radius and the atomic number, Z. For silicon, the channeling efficiency exceeds 35%, a record for negatively charged particles. This was possible due to the realization of a crystal with a thickness of the order of the dechanneling length. On the other hand, for germanium the efficiency is slightly below 10% due to the stronger contribution of multiple scattering for a higher-Z material. Nevertheless this is the first evidence of negative beam steering by planar channeling in a Ge crystal. Having determined for the first time the dechanneling length, one may design a Ge crystal based on such knowledge providing nearly the same channeling efficiency of silicon. The presented results are relevant for crystal-based beam manipulation as well as for the generation of e.m. radiation in bent and periodically bent crystals

Investigation on radiation generated by sub-GeV electrons in ultrashort silicon and germanium bent crystals

19sinoneWe report on the measurements of the spectra of gamma radiation generated by 855 MeV electrons in bent silicon and germanium crystals at MAMI (MAinzer MIkrotron). The crystals were 15 μ m thick along the beam direction to ensure high deflection efficiency. Their (111) crystalline planes were bent by means of a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature. In such a way it was possible to investigate the radiation emitted under planar channeling and volume reflection as a function of the curvature of the crystalline planes. We showed that, using volume reflection, intense gamma radiation can be produced – with intensity comparable to that obtained in channeling but with higher angular acceptance. We studied the trade-off between radiation intensity and angular acceptance at different values of the crystal curvature. The measurements of radiation spectra have been carried out for the first time in bent germanium crystals. In particular, the intensity of radiation in the germanium crystal is higher than in the silicon one due to the higher atomic number, which is important for the development of the X-ray and gamma radiation sources based on higher-Z deformed crystals, such as crystalline undulators.noneBandiera L.; Sytov A.; De Salvador D.; Mazzolari A.; Bagli E.; Camattari R.; Carturan S.; Durighello C.; Germogli G.; Guidi V.; Klag P.; Lauth W.; Maggioni G.; Mascagna V.; Prest M.; Romagnoni M.; Soldani M.; Tikhomirov V.V.; Vallazza E.Bandiera, L.; Sytov, A.; De Salvador, D.; Mazzolari, A.; Bagli, E.; Camattari, R.; Carturan, S.; Durighello, C.; Germogli, G.; Guidi, V.; Klag, P.; Lauth, W.; Maggioni, G.; Mascagna, V.; Prest, M.; Romagnoni, M.; Soldani, M.; Tikhomirov, V. V.; Vallazza, E

Investigation on radiation generated by sub-GeV electrons in ultrashort silicon and germanium bent crystals

We report on the measurements of the spectra of gamma radiation generated by 855 MeV electrons in bent silicon and germanium crystals at MAMI (MAinzer MIkrotron). The crystals were 15 \upmu \text {m} thick along the beam direction to ensure high deflection efficiency. Their (111) crystalline planes were bent by means of a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature. In such a way it was possible to investigate the radiation emitted under planar channeling and volume reflection as a function of the curvature of the crystalline planes. We showed that, using volume reflection, intense gamma radiation can be produced – with intensity comparable to that obtained in channeling but with higher angular acceptance. We studied the trade-off between radiation intensity and angular acceptance at different values of the crystal curvature. The measurements of radiation spectra have been carried out for the first time in bent germanium crystals. In particular, the intensity of radiation in the germanium crystal is higher than in the silicon one due to the higher atomic number, which is important for the development of the X-ray and gamma radiation sources based on higher-Z deformed crystals, such as crystalline undulators