Search results for " hydrocarbon"
showing 10 items of 300 documents
Prenatal exposure to residential air pollution and infant mental development: modulation by antioxidants and detoxification factors.
2011
Background: Air pollution effects on children’s neurodevelopment have recently been suggested to occur most likely through the oxidative stress pathway. Objective: We aimed to assess whether prenatal exposure to residential air pollution is associated with impaired infant mental development, and whether antioxidant/detoxification factors modulate this association. Methods: In the Spanish INfancia y Medio Ambiente (INMA; Environment and Childhood) Project, 2,644 pregnant women were recruited during their first trimester. Nitrogen dioxide (NO2) and benzene were measured with passive samplers covering the study areas. Land use regression models were developed for each pollutant to predict aver…
Metabolic activity of fresh and cryopreserved cynomolgus monkey (Macaca fascicularis) hepatocytes
2000
1. The effect of cryopreservation on the metabolic capacity of monkey hepatocytes over 4 h in suspension and 24 h in culture was determined. Hepatocytes were diluted in a buffer containing 10% DMSO and frozen in a computer-controlled chamber. 2. Initial ethoxyresorufin and ethoxycoumarin O-deethylase (ECOD) activities were the same in fresh and cryopreserved (CP) hepatocytes. ECOD activity in suspensions declined over 4 h but was the same in fresh and CP hepatocytes. 3. The formation of testosterone hydroxy (OHT) metabolites (namely 6beta-OHT, 2beta-OHT, 16beta-OHT, 16alpha-OHT, 15beta-OHT, 2alpha-OHT and 6beta-OHT) was unaffected by cryopreservation. The loss of OHT activities over 4 h in …
Permissive and suppressive effects of dexamethasone on enzyme induction in hepatocyte co-cultures.
2002
1. Steroids are known to act as permissive factors in hepatocytes. This study shows that dexamethasone (DEX) is a permissive factor for induction of CYP2B1/2, CYP3A1, CYP2A1 and probably also CYP2C11 in cultures with primary rat hepatocytes. 2. The induction factor of phenobarbital (PB)-induced formation of 16beta-hydroxytestosterone (OHT), a testosterone biotransformation product predominantly formed by CYP2B1, is increased 18-fold by the addition of 32 nM DEX to the culture medium. Interestingly, higher concentrations of DEX up to 1000 nM led to a concentration-dependent maximally 5-fold decrease (p = 0.002) of phenobarbital-induced 16beta-OHT formation compared with the effect observed w…
Innovations in Extractive Phases for In-Tube Solid-Phase Microextraction Coupled to Miniaturized Liquid Chromatography: A Critical Review
2020
Over the past years, a great effort has been devoted to the development of new sorbents that can be used to pack or to coat extractive capillaries for in-tube solid-phase microextraction (IT-SPME). Many of those efforts have been focused on the preparation of capillaries for miniaturized liquid chromatography (LC) due to the reduced availability of capillary columns with appropriate dimensions for this kind of system. Moreover, many of the extractive capillaries that have been used for IT-SPME so far are segments of open columns from the gas chromatography (GC) field, but the phase nature and dimensions are very limited. In particular, polar compounds barely interact with stationary GC phas…
An Expanded 2D Fused Aromatic Network with 90-Ring Hexagons
2022
[EN]Two-dimensional fused aromatic networks (2D FANs) have emerged as a highly versatile alternative to holey graphene. The synthesis of 2D FANs with increasingly larger lattice dimensions will enable new application perspectives. However, the synthesis of larger analogues is mostly limited by lack of appropriate monomers and methods. Herein, we describe the synthesis, characterisation and properties of an expanded 2D FAN with 90-ring hexagons, which exceed the largest 2D FAN lattices reported to date. This work was carried out with support from the Basque Science Foundation for Science (Ikerbasque),POLYMAT, the University of the Basque Country,Gobierno Vasco (BERC programme) and Gobierno d…
O-Doped Nanographenes: A Pyrano/Pyrylium Route Towards Semiconducting Cationic Mixed-Valence Complexes
2020
Herein we report an efficient synthesis to prepare O‐doped nanographenes, which derive from the longitudinally and latitudinally p‐extension of pyrene. The derivatives are highly fluorescent and feature low‐oxidation potentials. Exploiting electrooxidation, crystals of cationic mixed valence (MV) complexes were grown in which the organic salts organize into face‐to‐face p‐ p stacks, a favorable solid‐state arrangement for organic electronics. Variable‐temperature EPR measurements and relaxation studies suggest a strong electron delocalization along the longitudinal axis of the columnar p‐stacking architectures. Electric measurements of single crystals of the MV salts exhibited a semiconduct…
2,9-Dimethylpicene: Synthesis, Mutagenic Activity, and Identification in Natural Samples
1990
Abstract 2,9-Dimethylpicene (2,9-DMPic) has been conveniently synthesized via a new route involving oxidative photocyclization of suitable substituted diarylethylenes and has been characterized by high-resolution 400-MHz 1H-NMR spectroscopy. Furthermore, 2,9-DMPic exhibits a typical line narrowed emission spectrum in n-decane matrix frozen at 15 K (Shpol'skii effect). Its unambiguous identification in a natural sample has been performed by this technique, providing strong evidence for the formation of this compound through aromatization of triterpenoid natural precursors. The mutagenicity of this naturally occurring methylated polycyclic aromatic hydrocarbon (PAH) has been examined in six h…
Effects of Polycyclic Aromatic Hydrocarbons on Lung Function in Children with Asthma: A Mediation Analysis.
2022
Studies investigating the association between urinary Polycyclic Aromatic Hydrocarbons (PAHs) and asthma in children provided inhomogeneous results. We aimed to use Mediation Analysis to discover whether a link between urinary PAHs and lung function exists and if it might be ascribed to a direct or a symptom-mediated (indirect) effect in children with asthma. This single-center prospective study was conducted in Palermo, Italy, between March and July 2017 and involved 50 children with persistent mild-moderate asthma, aged 6–11 years. At each time visit (day 0, 30, 60, and 90), physical examination, spirometry, and urine collection for detection of urinary cotinine and PAHs were performed. A…
Emerging contaminants related to the occurrence of forest fires in the Spanish Mediterranean
2017
Forest fires can be a source of contamination because, among others, of the use of chemicals to their extinction (flame retardants, FRs), or by the production of Polycyclic Aromatic Hydrocarbons (PAHs) derived from high temperature alteration of organic matter. Up to our knowledge, this study is the first to assess the direct (PAHs 16 on the USA EPA's priority list), and indirect [tri- to hepta- brominated diphenyl ethers (PBDEs), organophosphorus flame retardants (PFRs) and perfluoroalkyl substances (PFASs)] contamination related to forest fires. The abundance and distribution of these contaminants were monitored on two Mediterranean hillslopes, one burned and one unburned, near Azuébar (S…
Possible impacts of Hg and PAH contamination on benthic foraminiferal assemblages: An example from the Sicilian coast, central Mediterranean
2007
The Palermo and Augusta urban/industrial areas (Sicily) are examples of contaminated coastal environments with a relatively high influx of unregulated industrial and domestic effluents. Three sediment box-cores were collected offshore of these urban/industrial areas in water depths of 60-150 m during two cruises (summers 2003/2004), dated by (210)Pb and (137)Cs, and analysed for total mercury concentration and total polycyclic aromatic hydrocarbon (PAH) concentration. Benthic foraminiferal assemblages were also examined (in terms of their distribution and morphology) to assess the potential use of benthic foraminifera as bioindicators of pollutant input and environmental change in these Med…