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A hexagonal-grid based template system has been developed to a predicting tool of CYP3A4-mediated reactions through the reconstitution of the active site with the assembly of the ligands. Simultaneous interactions of flattened-shape ligands at two sites of CYP3A4, oxidizing- and triggering-sites, are essential ideas, which were supported in the simulation results of various ligands on the template. The interactions were accomplished with either uni-molecule bindings or bi-molecule bindings with ligands termed pro-metabolized and trigger molecules. The template shape was determined mainly through reciprocal comparisons of simulation results with available experiment data mainly on recombinant CYP3A4-mediated reactions of polyaromatic hydrocarbon (PAH) ligands. Through the applications of various PAH and non-PAH ligands on the template, couple region-specific interactions including mechanisms to facilitate ligand movement from the initial site to a place near heme-oxygen and to trigger of catalyses are envisioned. These are very effective tools to verify candidates of CYP3A4 ligands as the good or poor substrates. The bi-molecule binding idea also explains so called "cooperative bindings with activator/effector" as interactions with non-identical trigger molecules on this CYP3A4-template system, and also offers possible mechanisms of the non-linear kinetic behavior.

Upon treatment of the polyaromatic hydrocarbon (PAH) grafted hydrazones HL (1) with [RhCl(PPh3)3], complexes of type [Rh(L)Cl2(PPh3)2] (2) have been isolated. The X-ray diffraction technique has been used to elucidate the structures of three complexes. The rich spectral features of the complexes in the UV–vis region have been explained by TD-DFT and their redox active nature has been validated from the well-defined responses at mild potentials as well as from a theoretical investigation of the redox orbitals. Intra-molecular π–π stacking interactions coupled with the electron withdrawing ability of the pendant PAH moiety within the ligand framework play a significant role in altering the mode of coordination (flexidentate behaviour of HL) as well as the metal–ligand bond parameters.

This prediction system is based on placements of CYP1A2-substrates on a hexagonal-grid template in a way following the rule generated from the relationship of the substrate-structure and selective-area uses on the template, and also the rule for a triggering-event to initiate the catalytic reactions. Clear relationship found between the placements and preferred-order of regioselective reactions from the comparison of experimental data of polyaromatic hydrocarbon (PAH)-substrates was implemented in this system. The template generated is consisted of two flat-shape regions (Thin- and Thick-Areas) and Site of Oxidation. The latter is located at an overlapping region of Thin- and Thick-Areas and has a shape of cubic-like block. Thin-Area and Thick-Area are not on the same plane, and bend slightly at their overlapping parts. Two Entrances and two Gatekeepers are situated each near the top and middle bottleneck-parts of Thin-Area and Thick-Area to restrict the substrate entry. A procedure of stepwise movement of substrates resided on Thick-Area is introduced to define the regioselectivity. A specific part (termed Trigger-Region) showing high placement rates was found at a region away from Site of Oxidation on the template, assuming that substrate-sittings at Trigger-Region are essential for the initiation of catalytic reactions. These observations lead us an idea of simultaneous bi-molecule placement to fulfill both the essential sitting at Trigger-Region and regioselectivity of metabolisms, although a uni-molecule sitting co-covering Trigger-Region is also possible to contribute for the metabolite formation. Substrates of CYP1A2 are verified from distinct points including selective use of Thin-Area, Trigger-molecule Harboring Area, dual access routs, Facial-side Movement as well as their sizes. In addition, inhibitory actions as well region/stereo selective oxid/reductions of both PAH and non-PAH molecules are verified with their supposable interaction mechanisms in this prediction system.

The Canadian Health Measures Survey (CHMS), an ongoing national health survey conducted in two-year cycles, collects extensive biomonitoring data that is used to assess the exposure of Canadians to environmental chemicals of concern. Combining data from multiple cycles of the CHMS allows for the calculation of robust regional estimates of chemical concentrations in blood and urine. The objective of this work was to compare biomarkers of exposure to several environmental chemicals for the provinces of Quebec and Ontario, two major CHMS regions, as well as the entire CHMS (representing Canada) minus Quebec (CMQ), and the entire CHMS minus Ontario (CMO), and to interpret differences between regions. Geometric means and 95th percentiles of blood and/or urinary concentrations of 45 environmental chemicals or their metabolites for Ontario, Quebec, CMQ, and CMO were calculated by combining the two most recent cycles of data available for a chemical (cycles 1 and 2, or cycles 2 and 3) from the first three cycles of the CHMS (2007-2013). Weighted one-way ANOVA was used to test the differences between regional estimates. After applying a Bonferonni-Holm adjustment for multiple comparisons, the following measures were significantly higher in Quebec as compared to Ontario and CMQ: blood lead, urinary lead and the urinary polyaromatic hydrocarbon (PAH) metabolites, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2- hydroxyphenanthrene and 3-hydroxyphenanthrene. In Quebec compared to CMQ only, urinary 2-hydroxfluorene, 3-hydroxyfluorene, 2-hydroxynaphthalene, and 4-hydroxyphenanthrene were higher. The concentration of urinary fluoride was significantly higher in Ontario as compared to Quebec and CMO. Blood manganese and urinary fluoride were significantly lower in Quebec compared to CMQ, and blood and urinary selenium were significantly lower in Ontario compared to CMO. Regional differences in tobacco use, age of dwellings and drinking water fluoridation are among the possible contributing factors to some of the observed differences. In conclusion, this is the first study where biomonitoring data from multiple cycles of CHMS were combined in order to generate robust estimates for subsets of the Canadian population. Such assessments can contribute to a regional-level prioritization of control measures to reduce the exposure of Canadians to chemicals in their environment.

Substituted chrysenes have been swiftly synthesised by the 6-endo-dig cyclisation of ethynylnaphthalenes using platinum(II) chloride. Cyclisation precursors were directly prepared from commercially available 2-bromoaldehydes in a telescoped synthetic procedure involving a Cannizzaro triggered cascade and subsequent dehydration and desilylation. This short synthetic procedure allows rapid access to derivatives of biologically active molecules with useful electronic properties.

A series of locally twisted dual-functional materials namely PIPT , PITT and PIFT have been designed and synthesized by introducing different polyaromatic hydrocarbon groups to a phenanthroimidazole backbone through a thiophene bridge. In these molecules, the thiophene bridge and phenanthroimidazole platform are nearly coplanar and this endows these materials with relatively shallow HOMO levels (−5.35 to −5.21 eV). On the other hand, the bulky polyaromatic hydrocarbon units introduce non-planar twisty structures which reduce molecular aggregations. These three materials show color-tunable emission (emission peak from 468 to 532 nm in film) and high thermal stability ( T g > 160 °C). Simple trilayer devices using these three phenanthroimidazole derivatives as non-doped emitting layers exhibit low turn-on voltages (2.3–2.7 V) and high maximum efficiencies of 3.74, 6.15 and 6.89 cd/A for PIPT , PITT and PIFT , respectively. Above all, owing to their shallow HOMO levels for enabling efficient hole-injection, even simpler bilayer devices employing these materials as hole-transporting emitters show low turn-on voltages (2.6–2.8 V) and high efficiencies of 5.77 cd/A for PIPT , 6.03 cd/A for PITT and 6.04 cd/A for PIFT , respectively. These comparable performances with those of the trilayer configurations show the efficient hole-injection/transport ability of these three newly developed emitters.

We perform a theoretical study of the electronic properties of polyaromatic hydrocarbon (PAH) molecules, as well as benzene and graphene, adsorbed on copper and gold. The PAH molecules studied are ...

The potential for polyaromatic hydrocarbon (PAH) emissions from laser printers has been examined using a simulated printing process and a detailed chemical analysis of printer toner. We have analysed the PAH content of both carbon black (a toner constituent) and toner before and after heating and have found measurable evaporation and subsequent condensation of PAHs. Based on our analysis we have estimated a maximum possible PAH emission rate of 82.1 μg min−1 of printing for a 10% page coverage. Our VOC emission results agree well with those of other authors. The concentrations of individual PAHs in the emissions were relatively low, however non-trivial, especially long term.

Ten halophilic Archaea (Haloarchaea) strains able to degrade aromatic compounds were isolated from five hypersaline locations; salt marshes in the Uyuni salt flats in Bolivia, crystallizer ponds in Chile and Cabo Rojo (Puerto Rico), and sabkhas (salt flats) in the Persian Gulf (Saudi Arabia) and the Dead Sea (Israel and Jordan). Phylogenetic identification of the isolates was determined by 16S rRNA gene sequence analysis. The isolated Haloarchaea strains were able to grow on a mixture of benzoic acid, p-hydroxybenzoic acid, and salicylic acid (1.5 mM each) and a mixture of the polycyclic aromatic hydrocarbons, naphthalene, anthracene, phenanthrene, pyrene and benzo[a]anthracene (0.3 mM each). Evaluation of the extent of degradation of the mixed aromatic hydrocarbons demonstrated that the isolates could degrade these compounds in hypersaline media containing 20% NaCl. The strains were shown to reduce the COD of hypersaline crude oil reservoir produced waters significantly beyond that achieved using standard hydrogen peroxide treatment alone.

The literature shows that most interlaboratory comparisons deal with determination of inorganic compounds or physico-chemical parameters. The determination of organic compounds, particularly in environmental samples, is still a challenging analytical problem, which is why there are few interlaboratory comparisons on this subject. The amount and the quality of information obtained from interlaboratory comparisons depend on both their organizer (who selects and prepares material for investigation, and provides statistics based on the results of measurements) and participants (who carry out measurements, determine the validation parameters of the relevant analytical procedure, and publish the results of analyses). We discuss the difficulties in determining organic compounds on the basis of our own investigations on polyaromatic hydrocarbons and polychlorinated biphenyls in environmental samples. We present means of overcoming these difficulties as conclusions emerging from the results of interlaboratory comparisons.

The main objective of the project “Screening methods for Water data InFormaTion in support of the implementation of the EU Water Framework Directive” (SWIFT-WFD) was to support the successful implementation of the WFD, which strongly depends on the quality and the comparability of monitoring data from river basin to river basin. In order to evaluate the performance of the laboratories using both classical and screening/emerging methods involved in the analysis of priority substances listed in the WFD, project activities included organization of three Proficiency Testing (PT) schemes at the European level for the determination of trace elements, major components, polyaromatic hydrocarbons and pesticides in water matrices, using the quality-control materials prepared within the project activities. The results of the three PT schemes were evaluated to provide a basis of information about the performance and thus the capacities of European analytical laboratories to comply with the requirements set out in the WFD.

A method for self-modeling curve resolution (SMCR) of two-way data is proposed. It is demonstrated that with an arbitrary p -normalization ( p > 1), the two-way data points are located on a certain polyhedral hyper-“spherical” surface with the vertices constituted by the pure variables. This elucidates the geometry of an old discovery that two-way data points are bracketed by the pure variables. Thus a property of the polyhedral hyper-“sphere” is given, which states that the vertex vectors maximize a certain quadratic form over all points on the hyper-“spherical” surface. A procedure for determining pure variables in two-way data is then developed. Finally, an optimization algorithm to refine the resolution is suggested. With a good starting estimate that is as close as possible to the true pure profiles, the proposed method is expected to yield improved resolution compared to traditional resolution techniques. The proposed method is evaluated with two simulated data sets and two real chemical data sets from hyphenated chromatography–diode array detection (HPLC–DAD) of polyaromatic hydrocarbon in air particle samples. The results show that the proposed method gives satisfactory resolution for the four data sets.

A bioanalytical method based on nanoflow liquid chromatography coupled to a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry was developed to characterize selected polyaromatic hydrocarbon (PAH)-DNA adducts. The collision-induced dissociation of analytes results in characteristic fragmentation patterns that can be utilized to identify the DNA adducts. In the experiment, 32 B6C3F1 mice were exposed daily (4h/day) to asphalt fume in a whole-body inhalation chamber for 10 days; 16 nonexposed mice served as controls. The asphalt fume was generated at 180 degrees C and the concentrations of PAHs in the animal exposure chamber ranged from 152 to 198 mg/m3. The DNA adducts N2-deoxyguanosine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (N2-dG-BPDE); N6-deoxyadenosine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (N6-dA-BPDE), and N4-deoxycytidine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (N4-dC-BPDE) were identified. The concentrations of N2-dG-BPDE, N6-dA-BPDE, and N4-dC-BPDE adducts were determined to be 1.17, 0.97, and 0.68 pmol/mg DNA, respectively, in the lung tissue of exposed mice using the nanoflow technique. The total DNA adducts in exposed lung tissue was determined to be 8.35 pmol/mg DNA by 32P-postlabeling assay. In total, the results indicated that PAH DNA adducts were significantly elevated (p0.001) in the lung tissue of asphalt-fume-exposed mice relative to tissue from control animals.

The photocatalytic degradation of saturated aqueous solution of naphthalene and anthracene was studied over thin films of porous TiO2 particles on glass substrate, prepared by sol-gel process. Surface morphology and structural features were studied by SEM, TEM and Laser Raman Spectroscopy. These films have been found to be very efficient and the total photomineralisation of these organics to carbon dioxide and water occurs in air-equilibrated solution within 1 h. Concentration changes linearly with the illumination time, and high rate constants are obtained for the degradation of these organics. The pH of the solution changes with the irradiation time due to the formation of intermediate photoproducts, e.g., 5,8-dihydroxynaphthaquinone, and 9,10-anthraquinone, etc. Photodegradation mechanism and the detection of reaction intermediates have been discussed in details. (C) 2000 .

This paper provides an overview of analytical techniques and instruments used to monitor and characterize polycyclic aromatic compounds (PACs) in the environment. The basic operating principles of various analytical approaches and systems are presented. The review deals specifically with spectroscopic methods, chromatographic and hyphenated techniques, and field monitoring devices. Emphasis is given to portable devices that can be used under field conditions. Specific examples of analytical techniques and instruments developed in the authors's laboratories will be discussed to illustrate the usefulness and potential of these approaches for environmental monitoring and characterization of PACs.

The respiration quotient (Q R ) calculated from the actual (R A ) and potential respiration rate (R P ) after addition of glucose ( Q R = R A R P ) was compared with the PAH concentration of a contaminated site during bioremediation. A correlation coefficient of 0.997 was obtained. Comparison with respiration quotients of several contaminated and uncontaminated sites gives evidence that the quotient is a suitable indicator for easily biodegradable carbon sources in the soil and presents an adequate quick and easily determinable indicator for the efficiency of bioremediation processes.

5 different histidine-requiring strains of Salmonella typhimurium were used to test the mutagenic activity of 7 different fractions of Athabasca tar-sand. None of the 7 fractions (bitumen, maltenes, asphaltenes, saturated, monoaromatic, diaromatic and polyaromatic hydrocarbons), showed positive mutagenic response in any of the Salmonella typhimurium strains. We have tested a wide range of concentrations. The results obtained so far are consistent with the lack of mutagenic activity of all investigated fractions in the absence and in the presence of metabolic activation. Assuming that there might be an association between the absence of mutagenic activity and the complexity of the tar-sand fractions, we investigated the effect of the polyaromatic hydrocaron fraction on the mutagenicity of the carcinogenic agent 2-aminoanthracene. The data obtained indicate clearly that the polyaromatic hydrocarbon fraction suppresses the mutagenic activity of 2-aminoanthracene.

The effect of the gradient on high-performance liquid chromatographic separations has been examined from a theoretical standpoint, using computer simulations to visualize the effects of different variables. Samples to be separated by gradient elution can be classified according to their separation characteristics into three groups (referred to here as cases I, II and III). Each of these sample types responds differently to a change in gradient conditions. Case III samples exhibit changes in band spacing when the gradient conditions are varied, and gradients composed of multiple linear segments are especially useful for controlling band spacing and resolution for such samples. The effect of different gradient conditions (starting %B, gradient steepness and gradient shape) on the separation of case III samples is examined in detail.

A novel method for particle microstructure analysis is introduced. A screen-type diffusion battery is shown to be applicable for sub-monolayer detection on 7–8 nm particles if the penetration is as small as 1%. A combination of this method with in situ near-UV photoemission (PE) from Perylenecoated C particles leads to a clear distinction between adsorption and condensation. In submonolayer adsorption, PE rises very steeply with the coverage (30% per tenth of a monolayer), and therefore allows extremely sensitive detection of polyaromatic hydrocarbons (PAHs). For condensation of the PAH in thicker layers, PE indicates when the particles are completely surrounded by the PAH.