Pilot plant study of the microbial flora in a diesel fuel contaminated soil

This study focused on the impact of a recent soil pollution of diesel fuel on a site and its indigenous microbial flora. A pilot plant (0.5 m3) was set up and filled with a soil (about 700 kg), artificially and uniformly polluted with diesel fuel (7 g/kg). This plant was then chemically and biologically monitored during the whole experiment (about two years). During the monitoring, a morphological change of the microbial colonies was observed. This was probably due to the acclimation phenomena to the pollution. With batch kinetic studies (10 ml) and increasing the selective pressure of the pollutant, it was possible to select and isolate a microbial consortium and a single strain that developed the ability to use different diesel fuel fractions as carbon sources. GC-MS analytical techniques were used. Results showed that different fractions were degraded at different times. In the batch system, in 7 days, the microbial consortium degraded some aromatic hydrocarbons. The isolate strain, in 20 days, degraded linear hydrocarbons. After a two years acclimation, it was possible to obtain, from a pilot plant, a microbial consortium and a strain able to degrade diesel fuel, for a future bioremediation in situ process.     

Globally generated vector bundles of rank 2 on a smooth quadric threefold

We investigate the existence of globally generated vector bundles of rank 2 with _c1≤3$c_1\le 3$ on a smooth quadric threefold and determine their Chern classes. As an automatic consequence, every rank 2 globally generated vector bundle on Q$Q$ with _c1=3$c_1=3$ is an odd instanton up to twist.     

Cohomological characterization of vector bundles on Grassmannians of lines

We introduce a notion of regularity for coherent sheaves on Grassmannians of lines. We use this notion to prove some extension of Evans–Griffith criterion to characterize direct sums of line bundles. We also give, in the line of previous results by Costa and Miró-Roig, a cohomological characterization of exterior and symmetric powers of the universal bundles of the Grassmannian.     

Chemical Bonding in Polarised Push–Pull Ethylenes

1,1‐Diamino‐2,2‐bis(triflyl)ethylenes with both twisted and planar structures around the partial “C=C” bond were synthesised. Bonding properties in these compounds were analysed by an experimental approach using high‐resolution X‐ray diffraction data treated with X‐ray wavefunction refinement (XWR). In the twisted compound, a dominant contribution of the charge‐separated resonance structure was revealed. On the contrary, the nearly planar compound still showed π‐bonding character, however, with a considerable contribution of the charge‐separated resonance structure.     

Vector bundles on Hirzebruch surfaces whose twists by a non-ample line bundle have natural cohomology

Here we study vector bundles E on the Hirzebruch surface F _e such that their twists by a spanned, but not ample, line bundle M = _Fe (h + ef) have natural cohomology, i.e. h ⁰(F _e , E(tM)) > 0 implies h ¹(F _e , E(tM)) = 0.      

Globally generated vector bundles on the Segre threefold with Picard number two

We classify globally generated vector bundles on with small first Chern class, i.e. , . Our main method is to investigate the associated smooth curves to globally generated vector bundles via the Hartshorne–Serre correspondence.     

Atomistic Simulations of COSAN: Amphiphiles without a Head‐and‐Tail Design Display “Head and Tail” Surfactant Behavior

Cobaltabisdicarbollide (COSAN) anions have an unexpectedly rich self‐assembly behavior, which can lead to vesicles and micelles without having a classical surfactant molecular architecture. This was rationalized by the introduction of new terminology and novel driving forces. A key aspect in the interpretation of COSAN behavior is the assumption that the most stable form of these ions is the transoid rotamer, which lacks a “hydrophilic head” and a “hydrophobic tail”. Using implicit solvent DFT calculations and MD simulations we show that in water, 1) the cisoid rotamer is the most stable form of COSAN and 2) this cisoid rotamer has a well‐defined hydrophilic polar region (“head”) and a hydrophobic apolar region (“tail”). In addition, our simulations show that the properties of this rotamer in water (interfacial affinity, micellization) match those expected for a classical surfactant. Therefore, we conclude that the experimental results for the COSAN ions can now be understood in terms of its amphiphilic molecular architecture.     

The Bis(ferrocenyl)phosphenium Ion Revisited

The bis(ferrocenyl)phosphenium ion, [Fc₂P]⁺, reported by Cowley et al. (J. Am. Chem. Soc. 1981 , 103, 714–715), was the only claimed donor‐free divalent phosphenium ion. Our examination of the molecular and electronic structure reveals that [Fc₂P]⁺ possesses significant intramolecular Fe???P contacts, which are predominantly electrostatic and moderate the Lewis acidity. Nonetheless, [Fc₂P]⁺ undergoes complex formation with the Lewis bases PPh₃ and IPr to give the donor–acceptor complexes [Fc₂P(PPh₃)]⁺ and [Fc₂P(IPr)]⁺ (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazole‐2‐ylidene).