Search results for "hydrocarbons"
showing 10 items of 368 documents
The Influence of Stimulation Techniques on the Microbiological Changes and n-Alkane Transitions in the Soil Contaminated of Petroleum-Derived Substan…
2019
Removal of petroleum products from contaminated soil is a long-term process requiring attention and constant monitoring. The aim of this study was to determine the effect of Fyre-Zyme enzyme preparation and/or calcium carbonate on microbiological changes and conversion of n-aliphatic hydrocarbons in soil contaminated of petroleum-derived substances. The material for testing was soil contaminated with petroleum substances. The total concentration of n-alkanes with a C8–C40 chain length was 420.1 mg·kg−1 DM. The pot tests were carried out by introducing stimulators. As a decomposition promoter for n-alkanes in contaminated soil, a 6% water solution of Fyre-Zyme and/or 1% sterile CaCO3 was use…
Dicyclopentaannelated Hexa-peri-hexabenzocoronenes with a Singlet Biradical Ground State
2021
Abstract Synthesis of two dicyclopentaannelated hexa‐peri‐hexabenzocoronene (PHBC) regioisomers was carried out, using nonplanar oligoaryl precursors with fluorenyl groups: mPHBC 8 with two pentagons in the “meta”‐configuration was obtained as a stable molecule, while its structural isomer with the “para”‐configuration, pPHBC 16, could be generated and characterized only in situ due to its high chemical reactivity. Both PHBCs exhibit low energy gaps, as reflected by UV‐vis‐NIR absorption and electrochemical measurements. They also show open‐shell singlet ground states according to electron paramagnetic resonance (EPR) measurements and density functional theory (DFT) calculations. The use of…
Ecotoxicity assessment of natural attenuation effects at a historical dumping site in the western Baltic Sea.
2005
During the late 1950s and early 1960s of the past century, industrial waste material highly enriched in various contaminants (heavy metals, PAHs) was dumped in the inner Mecklenburg Bay, western Baltic Sea. Large-scale shifts in the spatial distribution of heavy metals in surface sediments were mapped by geochemical monitoring in the mid-1980s and 12 years later in 1997. A further study in 2001 was designed to investigate the small-scale spatial distribution of contaminants inside, on top of, and around the historical dumping ground and to examine possible effects to benthic organisms (Arctica islandica, microbiological toxicity tests). The site is located within an area characterized by a …
Communication versus waterproofing: the physics of insect cuticular hydrocarbons
2019
Understanding the evolution of complex traits is among the major challenges in biology. One such trait is the cuticular hydrocarbon (CHC) layer in insects. It protects against desiccation and provides communication signals, especially in social insects. CHC composition is highly diverse within and across species. To understand the adaptive value of this chemical diversity, we must understand how it affects biological functionality. So far, CHCs received ample research attention, but their physical properties were little studied. We argue that these properties determine their biological functionality, and are vital to understand how CHC composition affects their adaptive value. We investigat…
The bioremediation potential of the Priolo Harbour (SR, Italy): isolation, identification and catabolic ability of hydrocarbonoclastic bacteria
2013
The petrochemical site of Priolo-Augusta-Melilli (Sicily, Italy), is a Site of National Interest (SIN) due to high levels of contamination of the coastline and its remediation is urgently needed. Successful remediation strategies relying on the catabolic potential of marine hydrocarbonoclastic bacteria (HCB) have been described. HCB are specialised hydrocarbon (HC)-degrading marine bacteria that use HC almost exclusively as unique carbon and energy source and become dominant in oil-impacted environments. In order to identify the key hydrocarbon degraders and explore the natural bioremediation potential of the contaminated area, sediment cores and sea water were collected inside the Priolo H…
Vulnerability maps pollution to hydrocarbon and urban waste pollution in seawater intrusion areas
2004
De acuerdo con un proyecto nacional promovido por el Grupo Nacional Italiano para la Protección contra Riesgos Hidrogeológicos han sido publicados los mapas de vulnerabilidad (1:50.000) de parte del Territorio Italiano, particularmente algunos mapas de Sicilia: Montes Iblei, Moadonie, Sicani y el Monte Etna. Estos mapas se han vuelto documentos públicos para el manejo local del agua subterránea. Algunos fenómenos muy peligrosos han sido reportados en algunas áreas de Sicilia. Intervenciones antrópicas han creado basureros de residuos tóxicos sobre áreas vulnerables. Esta investigación explica las ventajas del uso de mapas de vulnerabilidad en estudio de tipos peligrosos de contaminación par…
Gold-Catalyzed Intramolecular Hydroamination of o-Alkynylbenzyl Carbamates: A Route to Chiral Fluorinated Isoindoline and Isoquinoline Derivatives
2013
Enantiomerically pure fluorinated isoindoline and dihydroisoquinoline scaffolds have been prepared through a diastereoselective addition of fluorinated nucleophiles to Ellman’s N-(tert-butanesulfinyl)imines followed by a sequence of Sonogashira cross-coupling/gold(I)-catalyzed cycloisomerization of the corresponding carbamate. A more favored 5-exo-dig mechanism was observed mainly due to an electronic effect of the fluorinated group.
Bioconcentration, biotransformation and elimination of pyrene in the arctic crustacean Gammarus setosus (Amphipoda) at two temperatures
2015
The influence of temperature on the bioaccumulation, toxicokinetics, biotransformation and depuration of pyrene was studied in the arctic marine amphipod Gammarus setosus. A two-compartment model was used to fit experimental values of total body burden, total metabolites and parent pyrene concentrations and to calculate toxicokinetic variables derived for two experimental treatments (2 and 8 °C). No statistically significant differences were observed with temperature for these toxicokinetic variables or bioconcentration factors. Contrarily, the Q10 values suggested that the toxicokinetic variables ke and km were temperature-dependent. This may be explained by the high standard deviation of …
Screening of halogenated aromatic compounds in some raw material lots for an aluminium recycling plant
2004
Four samples of scrap raw materials for an aluminium recycling plant were screened for the occurrence of persistent halogenated aromatic compounds. The samples contained waste from handling of electric and electronic plastics, filter dust from electronic crusher, cyclone dust from electronic crusher and light fluff from car shredder. In our screening analyses, brominated flame retardants were observed in all samples. Polybrominated diphenyl ethers (PBDE) were identified in all samples in amounts of 245–67450 ng/g. The major PBDE congeners found were decabromo- and pentabromodiphenyl ethers. 1,1-bis(2,4,6-tribromophenoxy)ethane, hexabromobenzene, ethyl-pentabromobenzene, tetrabromobisphenol-…
Selective recognition of aromatic hydrocarbons by endo-functionalized molecular tubes via C/N-H⋅⋅⋅π interactions
2018
Abstract Molecular recognition of aromatic hydrocarbons by four endo -functionalized molecular tubes has been studied by 1 H NMR spectroscopy, computational methods, and single crystal X-ray crystallography. The binding selectivity is rationalized by invoking shape complementarity and dipole alignment. The non-covalent interactions are proved to predominantly be C/N-H⋅⋅⋅ π interactions.