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Abstract The mediator of dioxin toxicity, aryl hydrocarbon receptor (AHR), has also important physiological functions. Selective AHR modulators (SAHRMs) share some effects of dioxins, except for their marked toxicity. We recently characterised toxicologically two novel SAHRMs, prodrugs IMA-08401 and IMA-07101 in rats, demonstrating that they are far less deleterious than the most toxic AHR-agonist, TCDD. Here, we analysed the in vitro toxicity and in silico AHR binding of the respective active, deacetylated metabolites, IMA-06201 (N-ethyl- N -phenyl-5-chloro-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-quinoline-3-carboxamide) and IMA-06504 (N-(4-trifluoromethylphenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide). In H4IIE rat hepatoma cells, IMA-06201 and IMA-06504 induced CYP1A1 with comparable potencies and efficacies to those of TCDD. They had little effect on cell viability as assessed by LDH leakage and MTT reduction assays, and were not mutagenic in the Ames test, but IMA-06504 elicited a maximally 2.7-fold increase in micronuclei. Molecular docking simulations showed that similar to TCDD, they occupy the central region of AHR ligand binding cavity. Hence, while showing low to negligible in vitro toxicity, these novel SAHRMs bind to the AHR qualitatively in a similar fashion to TCDD, and appear comparably powerful AHR agonists. Combined with our earlier results demonstrating that they seem considerably less toxic in vivo than TCDD, these compounds are thus highly interesting new SAHRMs. Highlights • IMA-06201 and IMA-06504 are selective AHR modulators. • As CYP1A1 inducers, they appear comparable to TCDD in potency and efficacy. • They also show low to negligible cytotoxicity and mutagenicity in vitro. • Based on in silico modelling, their binding to the AHR resembles that of TCDD. • Therefore, they have potential as drug compound candidates and research tools. [ABSTRACT FROM AUTHOR]

The paper is concerned with the study of triboluminescence of lanthanide salts in an atmosphere of hydrocarbon gases (methane, its homologues, ethylene, and acetylene). The luminescence of *CH and/or *C 2 appeared after mechanochemical decomposition of these gases during tribodestruction of crystals was observed in all the gases. Injection of hydrocarbon gases suppressed the glow of *N 2 (a gas component in a triboluminescence spectrum of air). When heavier hydrocarbon gases were used, the triboluminescence spectra indicated that *C 2 emission predominated over the luminescence of a *CH radical. The intensity of *C 2 emission decreased with an increase in a hydrocarbon chain. The decomposition mechanism of hydrocarbon gases to form *CH and *C 2 during triboluminescence of lanthanide salts in the atmosphere of these gases is discussed. A similar decomposition mechanism of these gases in electric discharges is also discussed. The experimental spectra of the *C 2 (Swan bands) were used to calculate and to estimate some characteristics of the radiating medium. The vibrational temperatures T vib ~ 4000–5000 K calculated for different hydrocarbon gases exceeded the rotational one T rot ˂ 3000 K. This indicates that the working medium is a nonequilibrium plasma, in which the C 2 excitation occurs due to electron impact. In addition, it was assumed that the excitation could also be caused by collision with heavy particles, for example, hot gas molecules as a result of gas heating during a series of consecutive experiments. [ABSTRACT FROM AUTHOR]

Some efforts made to date in curbing greenhouse gases from the transportation sector have focused on the production of biofuels. Biomass derived oils have advantages that outweigh their flaws as fuels. Petroleum range hydrocarbons can be produced via secondary processing of bio-oils. Feedstock type and availability, catalyst choice and operating conditions have a significant influence on the potentials of biomass as a feedstock for petroleum Range hydrocarbons. Despite numerous works done, it is noted that more research is needed towards commercialising biomass conversion techniques with the view to producing petroleum range hydrocarbon and biomass like algae and palm oil have been seen to be very promising sources of biofuels. [ABSTRACT FROM AUTHOR]

Pyrene, a member of the polycyclic aromatic hydrocarbons (PAHs), contributes to abnormality in the size of the brain and the swimming behavior of pufferfish ( Takifugu niphobles ) larvae. We hypothesized that the aryl hydrocarbon receptor (AHR) may mediate pyrene-induced toxic effects because AHR is assumed to be a candidate for the downstream target of PAHs in many cases. To identify the contribution of AHR on developing pufferfish, we performed exposure experiments using β-naphthoflavone, an agonist of AHR. We found that the toxic effects of pyrene and β-naphthoflavone in pufferfish larvae are fundamentally different. Pyrene specifically induced problems in the developing midbrain and in swimming behavior, while β-naphthoflavone affected the heartbeat rate and the size of the yolk. These results suggest that the behavioral and morphological abnormality caused by pyrene exposure is mediated by an AHR-independent pathway. Alternatively, defects caused by pyrene may be attributed to the inhibition of the FGF signal. [ABSTRACT FROM AUTHOR]

Optimum production from a hydrocarbon field takes place when technical parameters are optimized with respect to the operational and economic constraints. Well control parameters have an important role in making decisions for choosing efficient production scenario in a reservoir. Among the economical constraints cost of drilling and completion of wells, transportation and refinery costs and price of oil and gas can be named. In this paper, using single well model, the design of experiments and multi criteria decision making, determination of optimum production scenario based on a sector of South Pars gas field is addressed. Flow rate, well spacing, minimum wellhead pressure, production string size, deviation of wells and type of stimulation are decision parameters that are considered in this study. Economic indices chosen for economic analysis are net present value, internal rate of return and plateau time. First using the design of experiments and response surface methodology, proxy models are generated to predict economic indices for production scenarios and after validation of them, they are used for economic analysis and choosing the best scenario based on multi-criteria decision making. [ABSTRACT FROM AUTHOR]

After analyzing the molecular and isotopic compositions of 11 gas samples from Baka Gas Field, as well as the low molecular weight hydrocarbons (LMWHs) associated with them, the two types of natural gases are identified: biodegraded and non-biodegraded gases. No distinctions in molecular and isotopic compositions are observed between biodegraded and non-biodegraded methane, which may be partially due to the great solubility of methane in water. Anomalous molecular compositions and carbon and hydrogen isotopic ratios are observed among the biodegraded C 2+ gas components, which become more significantly fractionated in propane than in ethane, most probably due to their selective depletion by different strains of bacteria. The biodegradation resistance for C 6 –C 7 LMWHs associated with gases from Baka Gas Field follow the series Dimethylbutanes > Cyclohexane > Methylcyclopentane > 2-Methylpentane > 3-Methylpentane; Dimethylpentanes, 1,1-Dimethylcyclopentane and 1,2-Dimethylcyclopentanes > Methylcyclohexane >1,3-Dimethylcyclopentanes > 2-Methylhexane > 3-Methylhexane, respectively. Within the identical carbon numbers, two characteristics of biodegradation susceptibility for C 6 –C 7 LMWHs are observed: total poly-branched alkanes are more resistant to biodegradation than cycloalkanes, and mono-branched ones tend to be depleted by bacteria more easily than cycloalkanes; and isomers with adjacent methyl groups tend to be more resistant to biodegradation. These two characteristics could be effective tools for the identification of biodegraded hydrocarbons and for the determination of the degree of bacterial decomposition. After comparison with previous studies, it is evident that the varieties in bacteria strains result in the discrepancy of biodegradation efficiency for certain light hydrocarbon isomers. This research improves the understanding of the geochemical characteristics of biodegraded gases and provides additional tools for the identification of biodegraded gases and their degree of biodegradation. [ABSTRACT FROM AUTHOR]

The comprehensive performance of mechanical screens is extremely important for sand control and well completion and to the screen's service life. Screen sand retaining media are analyzed and divided into several classifications. The concepts of sand retaining ability, anti-plugging ability, and flow capacity are put forward to describe screen comprehensive performance. A new experimental method is set up to test the comprehensive performance of mechanical screens. During the test, formation sand is carried by fluid that flows radially against the screen to simulate the real process of sand retaining. The variation of flow rate, pressure difference through screen media, and permeability with time reflect the screen's dynamic characteristics. Based on test data, a set of evaluation indexes is proposed to describe the conductivity, sand retaining, anti-plugging ability, and relevant comprehensive performance of screens. The calculation method is also developed. This new integrated methodology for comprehensive performance evaluation was successfully applied in the selection of optimum screen type for a given reservoir. This method needs only a small number of tests and provides an effective means for evaluating and selecting an optimum screen type for reservoirs. [ABSTRACT FROM AUTHOR]

The analysis of multiple cracks in a heat exchanger tubeplate at a petrochemical plant led to experimental replication of in-service damage. High lifting stresses created a first leak that was repaired. Extended branched intergranular cracking developed from the tubeplate surface around the repair weld after few weeks of renewed operation. Chemical analyses failed to detect Na on crack surfaces, while operative conditions also allowed discarding a typical SCC cracking mechanism. Lack of radial interference between tubes and plate, lack of penetration and lack of fusion at tube to tubeplate weld roots were also thought as contributors to cracking. Microstructural analyses revealed martensite clusters in welds and HAZ, and austenite grain boundary precipitates in the tubeplate base material. Thermal cycles were applied to ex-service samples to replicate the conditions for these brittle micro constituents, which were found to be unstable at operating temperatures. Mechanical testing also replicated grain boundary weakness. This inadequate structure was related to welding without proper thermal cycles and heat treatments. [ABSTRACT FROM AUTHOR]

The reforming of diesel and diesel-like fuels plays a central role in the development of fuel cell systems for on-board power supplies. The vaporization of the fuel via a spray formation and the subsequent mixture with water vapor and air determine the quality of the reforming process, as is shown in this paper. By using a high quality nozzle residual hydrocarbons were below 25 ppmV during the reforming of standard diesel. Through the use of a fuel injector in pulsed operation, the load range was able to be increased from 1:1.67 to 1:6. Spray pattern analyses were conducted using a high-speed camera. The formation of the spray pattern lasted 1.5–2 ms. The testing of a fast-closing magnetic valve manufactured by GSR Ventiltechnik was carried out on the autothermal reformer (ATR) type AH2. It exist not any direct influence of the pulsed operation on hydrogen production. [ABSTRACT FROM AUTHOR]

In order to obtain the precise predicted values of methane/hydrogen/air burning velocities from simulations, the performances of GRI mech 3.0, Aramco mech 1.3, USC mech 2.0 and San diego mech mechanisms were systematically studied under various conditions by PREMIX code and compared with experimental data from literature. The conditions where each mechanism gave their good performance are obtained and concluded. The flowrate sensitivity and rate constants of key elementary reactions were analyzed to insight the different behavior of each mechanism. The results showed that all these widely used small hydrocarbon mechanisms could gave reasonable predictions for pure methane and methane hydrogen blends. Nevertheless, they lack sensitivity for rich hydrogen at elevated pressures due to their complex reactions competitions controlled by hydrogen sub model. USC mech 2.0 was found more suitable for being used at low hydrogen contents while San diego mech gained better results at high hydrogen contents. GRI 3.0 gave good predictions for methane hydrogen blends except for high initial pressures. Generally, Aramco mech 1.3 showed the best performance for all testing conditions. Moreover, there was relatively large deviation from the predicted results and experimental data in the transition regime where the hydrogen fractions were between 60% and 80%, it may could be optimized by tuning the rate constants of reactions. [ABSTRACT FROM AUTHOR]

The present paper investigated on the presence of some hydrocarbon contaminants, namely polycyclic aromatic hydrocarbons (PAHs), mineral oil hydrocarbons (MOH) comprising saturated (MOSH) and aromatic (MOAH) compounds, and polyolefin oligomeric saturated hydrocarbons (POSH) in olives and extra virgin olive oils from Tunisia. Olive fruits were collected in sites exposed to different environmental contamination, and the oil extracted both by physical mean (using an Abencor extractor) and with solvent (using microwave assisted extraction, MAE). Analytical determination was performed by SPE cleanup on silica cartridge followed by spectrofluorometric detection, for PAH, and on-line HPLC-GC-FID for MOH and POSH. Oils extracted from olives by physical mean, as well as extra virgin olive oils from the market, had PAH levels never exceeding the EU legal limits. All olive samples showed similar MOSH profiles, but not clear correlation between the variable contamination levels and considered sources of contamination, was evidenced. The average MOSH content in oil extracted from olives by solvent (11.1 mg/kg) was about four time higher than in oil extracted by physical mean (2.6 mg/kg). MOSH in extra virgin oil from the market ranged from 10.3 to 38.0 mg/kg, while MOAH were not detected. The higher MOSH levels found in oils from the market evidenced an important contribution due to oil processing and/or packaging. Two of the samples were clearly contaminated with polyolefin oligomeric hydrocarbons (POSH) migrated from the plastic cap. [ABSTRACT FROM AUTHOR]

The Liaodong Bay sub-basin is one of the most petroliferous sub-basins in the Bohai Bay basin. The fourth member of the Eocene Shahejie Formation (E 2 s 4 , 50.5–42 Ma) which is an important source rock interval in other sub-basins was rarely studied in the Liaodong Bay sub-basin. The hydrocarbon generating potential, biomarker assemblage and accumulation contribution for discovered oil fields of the E 2 s 4 source rock interval in the Liaodong Bay sub-basin were studied using geological and geochemical data. The E 2 s 4 source rocks in the Liaodong Bay sub-basin display relatively high total organic carbon contents (TOC) and Rock-Eval hydrogen indices (HI) and can be considered as a set of excellent oil-prone tendency source rocks. The source rocks interval is characterized mainly by relatively low Pristane/Phytane (Pr/Ph), C 19 /C 23 tricyclic terpane (C 19 /C 23 TT), C 24 tetracyclic terpane/C 26 tricyclic terpane (C 24 Tet/C 26 TT), low to medium hopane/sterane (H/S), medium 4-methyl steranes/ΣC 29 steranes ratio (4-MS/ΣC 29 ST), C 35 22S/C 34 22S hopane (C 35 /C 34 SH) and high gammacerane/αβC 30 hopane (G/H), extended tricyclic terpane ratio [ETR=(C 28 TT + C 29 TT)/(C 28 TT + C 29 TT + Ts)] and were deposited in anoxic to sub-oxic saline-water environment with no or minor terrigenous organic matter and medium dinoflagellate input. The maturity of E 2 s 4 source rocks in the Liaozhong and north Liaoxi sags is too high to provide oils for fields. The E 2 s 4 source rocks in the south and middle Liaoxi sag displayed opportune maturity within the oil window and were proved by oil-source correlation having important accumulation contribution for discovered oil fields in this area. The E 2 s 4 -derived oils should be taken seriously in the future exploration in the south and middle Liaoxi sag and on adjacent uplifts. [ABSTRACT FROM AUTHOR]

Crude oil contamination widely impacts soil as a result of release during oil and gas exploration and production activities. The success of bioremediation methods to meet remediation goals often depends on the composition of the crude oil, the soil, and microbial community. Earthworms may enhance bioremediation by mixing and aerating the soil, and exposing soil microorganisms to conditions in the earthworm gut that lead to increased activity. In this study, the common composting earthworm Eisenia fetida was tested for utility to improve remediation of oil-impacted soil. E . fetida survival in soil contaminated with two distinct crude oils was tested in an artificial (lab-mixed) sandy loam soil, and survival compared to that in the clean soil. Crude oil with a high fraction of light-weight hydrocarbons was more toxic to earthworms than the crude oil with a high proportion of heavy polyaromatic and aliphatic hydrocarbons. The heavier crude oil was added to soil to create a 30,000 mg/kg crude oil impacted soil, and degradation in the presence of added earthworms and feed, feed alone, or no additions was monitored over time and compared. Earthworm feed was spread on top to test effectiveness of no mixing. TPH degradation rate for the earthworm treatments was ~ 90 mg/day slowing by 200 days to ~ 20 mg/day, producing two phases of degradation. With feed alone, the rate was ~ 40 mg/day, with signs of slowing after 500 days. Both treatments reached the same end point concentrations, and exhibited faster degradation of aliphatic hydrocarbons < C21, but all fractions, including aromatics > C21, decreased. During these experiments, soils were moderately toxic during the first three months, then earthworms survived well, were active and reproduced with petroleum hydrocarbons present. This study demonstrated that earthworms accelerate bioremediation of crude oil in soils, including the degradation of the heaviest polyaromatic fractions. [ABSTRACT FROM AUTHOR]

The aquatic biota of the Arabian Gulf deals with exposure to chronic oil pollution, several constituents of which cause induction of Cytochrome P450 1A that serves as a biomarker of AhR ligand exposure. In this study, fluorescent aromatic compounds (FACs) in bile and 7-ethoxyresorufin-o-deethylase (EROD) catalytic activity were determined as a measure of exposure biomarkers in two fish species, yellow fin seabream ( Acanthopagrus latus ) and tonguesole ( Cynoglossus arel ) captured from Kuwait Bay and outside the Bay area. FACs in fish bile determined by using fixed-wavelength fluorescence (FF) showed high fluorescence ratios between FF290/335 and FF380/430 indicating predominant exposure to low molecular weight, naphthalene-rich petroleum products (375 ± 91.0 pg ml − 1 ). Exposures to benzo(a)pyrene-type high-molecular weight polycyclic aromatic hydrocarbons (PAHs) originating from burnt fuel were also present in appreciable concentration in the bile. The ratio of petrogenic to pyrogenic hydrocarbon was twofold higher in winter compared to summer months in both species. Seasonal effect on EROD was significant in tonguesole in Auha site ( P < 0.05); whereas seabream resisted seasonal change. Tonguesole is considered to be a suitable bioindicator of oil pollution in Kuwait Bay area. [ABSTRACT FROM AUTHOR]

Scorpions exhibit some of the lowest recorded water loss rates among terrestrial arthropods. Evaporative water loss to the surrounding environment occurs mainly through the integument, and thus its resistance to water loss has paramount significance for the ability of scorpions to tolerate extremely dry habitats. Cuticular hydrocarbons (HCs) deposited on the outer epicuticle play an important role in determining cuticular waterproofing, and seasonal variation in both cuticular HC quantity and composition has been shown to correlate with water loss rates. Precursor incorporation rates into cuticle HCs have been observed to be extremely low in scorpions compared with insects. We therefore used adult male Buthus occitanus (Buthidae) in order to test HC profile plasticity during acute exposure to 14 d and 28 d of experimental desiccation. Cuticular HC profile of hydrated scorpions was similar to that reported for several other scorpion species, consisting of similar fractions of n -alkanes and branched alkanes, with no evidence for unsaturation. Most abundant of the n -alkanes were n -heptacosane (C 27 ; 19 ± 2% of total HCs), n -nonacosane (C 29 ; 16 ± 1%) and n -hentriacontane (C 31 ; 11 ± 1%). Exposure to desiccation stress resulted in a significant increase in the total amount of extracted HCs, and in the relative abundance of branched alkanes at the expense of n -alkanes. Together with an increase in HC chain lengths, these changes mimic previously-reported seasonal variation among freshly-collected specimens. This indicates that scorpions respond to water shortage by regulating the properties of their passive integumental barrier to water loss. [ABSTRACT FROM AUTHOR]

Background There is no consensus on the association between exposure to hydrocarbons and the risk of Parkinson's disease (PD). We conducted a systematic review and meta-analysis to summarise the epidemiological evidence and included a new large case-control study. Methods Data were extracted following a predefined protocol. Risk estimates regarding the association between hydrocarbon exposure and PD were consolidated to produce a summary odds ratio (OR), 95% confidence intervals (CI), and p-value. In our case-control study, 1463 PD patients and 685 controls were recruited from clinical trials and completed a structured questionnaire describing their previous working exposure to hydrocarbons and other demographic measures. The association between exposure to hydrocarbons and risk of PD was evaluated using logistic regression. Results The systematic search identified 13 case-control studies matching the inclusion criteria. The meta-analysis included 3020 PD cases and 6494 controls. The summary OR was 1.32 (95% CI 1.08–1.62, p = 0.006) for hydrocarbon exposure (ever versus never). In the PD GEN study, occupational exposure to hydrocarbons significantly increased the risk of PD (OR = 1.61; 95% CI 1.10–2.36, p = 0.014), and risk dose-dependently increased for subjects exposed greater than 10 years compared to subjects never exposed (OR = 2.19; 95% CI 1.13–4.26, p = 0.021). The addition of PD GEN data increased the total numbers to 4483 PD cases and 7179 controls and strengthened the significant association (summary OR = 1.36; 95% CI 1.13–1.63, p = 0.001). Conclusions This systematic review supports a positive association between hydrocarbon exposure and PD. Data from prospective studies are required to reinforce the relationship between hydrocarbon exposure and PD. [ABSTRACT FROM AUTHOR]

The ligand-activated nuclear receptor AhR (aryl hydrocarbon receptor) mediates the response of hepatocytes to various exogenous compounds. AhR is classically activated by planar, aromatic hydrocarbons, but also by other, structurally rather unrelated compounds. Recent data show that the canonical Wnt/β-catenin signaling pathway is also involved in the regulation of hepatic zonal gene expression and drug metabolism in mammalian liver. Previous studies indicate that the loss of β-catenin in hepatocytes diminishes the response to the AhR agonists 3-methylcholanthrene (3MC) in vivo and to 2,3,7,8-tetrachlorodibenzo-[ p ]-dioxin in vitro . The knockout of β-catenin also impairs the zonal pattern of AhR target gene induction by 3MC. However, it is presently unknown whether the chemical nature of the AhR agonist influences the AhR/β-catenin interaction. Moreover, no information is available about the dose–response curves of AhR activation in the absence or presence of Wnt/β-catenin signaling. In the present study, we have analyzed AhR-dependent responses to different concentrations of structurally unrelated AhR agonists in vivo and in vitro . The results demonstrate that β-catenin is essential to obtain the maximum AhR response. Moreover, using transgenic mouse models which allow for the ablation of β-catenin at different age of mice, we demonstrate that the presence of β-catenin, not postnatal developmental effects in β-catenin-deficient livers, is responsible for the observed interplay of β-catenin and the AhR. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are found in ambient aerosols and particulate matter. Experimental studies have shown that PAHs and related chemicals can induce toxicological effects. The present study aimed to investigate the effects of PAHs and their derivatives on the respiratory and immune systems and the underlying mechanisms. The human bronchial epithelial cell line BEAS-2B was exposed to PAHs and their derivatives, and the cytotoxicity and proinflammatory protein expression were then investigated. A cytotoxic effect was observed in BEAS-2B exposed to PAH derivatives such as naphthoquinone (NQ), phenanthrenequinone (PQ), 1-nitropyrene (1-NP), and 1-aminopyrene (1-AP). In addition, 1,2-NQ and 9,10-PQ showed more effective cytotoxicity than 1,4-NQ and 1,4-PQ, respectively. Pyrene showed a weak cytotoxic effect. On the other hand, naphthalene and phenanthrene showed no significant effects. Pyrene, 1-NP, and 1-AP also increased intercellular adhesion molecule-1 expression and interleukin-6 production in BEAS-2B. The increase was partly suppressed by protein kinase inhibitors such as the epidermal growth factor receptor-selective tyrosine kinase inhibitor and nuclear receptor antagonists such as the thyroid hormone receptor antagonist. The present study suggests that the toxicological effects of chemicals may be related to the different activities resulting from their structures, such as numbers of benzene rings and functional groups. Furthermore, the chemical-induced increase in proinflammatory protein expression in bronchial epithelial cells was possibly a result of the activation of protein kinase pathways and nuclear receptors. The increase may partly contribute to the adverse health effects of atmospheric PAHs. [ABSTRACT FROM AUTHOR]

Products of a hydrocarbon fire accident have both chronic and acute health effects. They cause respiratory issues to lung cancer. While fire is the most frequent phenomenon among the offshore accidents, predicting the contaminants' concentration and their behavior are key issues. Safety measures design, such as ventilation and emergency routes based only on predicted contaminants' concentration seems not to be the best approach. In a combustion process, various harmful substances are produced and their concentration cannot be added. The time duration that any individual spends in different locations of an offshore installation also varies significantly. A risk-based approach considers the duration a person is exposed to contaminants at various locations and also evaluates the hazardous impacts. A risk-based approach has also an additivity characteristic which helps to assess overall risk. Through the current study, an approach is proposed to be used for risk assessment of combustion products dispersion phenomenon in a confined or semi-confined facility. Considering CO, NO2 and CH4 as the contaminants of concern, the dispersion of the substances over the layout of the facility after a LNG fire is modeled. Considering different exposure times for three major parts of the facility including the processing area, office area and the accommodation module, the risk contours of CO, NO2 and CH4 over the entire facility are developed. The additivity characteristic of the risk-based approach was used to calculate the overall risk. The proposed approach helps to better design safety measures to minimize the impacts and effective emergency evacuation planning. [ABSTRACT FROM AUTHOR]

Tsetse flies, like many insects, use pheromones for inter- and intra-specific communication. Several of their pheromones are cuticular hydrocarbons (CHCs) that are perceived by contact at close range. We hypothesized that for a successful implementation of the Sterile Insect Technique (SIT), along with proper identification of target area and target species, the target tsetse populations and the sterile flies must chemically communicate with each other. To study the population structuring of Glossina pallidipes in Ethiopia, CHCs were extracted and analyzed from three tsetse belts. As a comparative approach, wing morphometric analysis was performed. The analysis of the relative abundance of CHCs revealed that populations of G. pallidipes from the Rift Valley tsetse belt showed a distinct clustering compared to populations from the other two belts. The spatial pattern of CHC differences was complemented by the wing morphometric analysis. Our data suggest that CHCs of known biological and ecological role, when combined with wing morphometric data, will provide an alternative means for the study of population structuring of Glossina populations. This could aid the planning of area wide control strategies using SIT, which is dependent on sexual competence. [ABSTRACT FROM AUTHOR]

Serum proteins, especially fibrinogen, inactivate the lung surfactant mixture by adsorbing quickly and irreversibly to the alveolar air/aqueous interface. As a consequence of the inactivation, the surfactant becomes dysfunctional, and respiration cannot be maintained properly. Preventing the adsorption of surface active serum proteins to the air/water interface is important because this phenomenon causes fatal diseases such as acute respiratory distress syndrome (ARDS). Although some treatments exist, improvements in synthetic surfactants that can resist this inactivation are still expected. In this context, a novel ion pair lipid (IPL, CF 3 (CF 2 ) 7 SO 3 − (CH 2 CH 3 ) 3 N + (CH 2 OCH 2 ) 10 (CH 2 ) 15 CH 3 ) has been designed and synthesized. This surfactant reduces the inhibitory effect of fibrinogen by selectively interacting with DPPC (dipalmitoylphosphatidylcholine) and mimicking some of the interfacial properties of the pulmonary surfactant protein B (SP-B). Surface pressure–area isotherms and fluorescence microscopy images demonstrate that IPL can mix and interact synergistically with DPPC due to its unique molecular structure. Hysteresis behaviors of the monolayers, which are composed of mixtures of DPPC and IPL at different molar ratios, indicate that with increasing amounts of IPL, the lipid losses from the interface induced by the presence of fibrinogen significantly decrease. It is also found that IPL is able to adsorb to monolayers formed in the presence of fibrinogen, whereas fibrinogen cannot penetrate the monolayers formed in the presence of IPL. These results indicate that by mimicking some of the interfacial properties of SP-B, this novel hybrid molecule is promising in terms of preventing fibrinogen adsorption and therefore resisting surfactant inactivation. [ABSTRACT FROM AUTHOR]

Abstract: Cuticular hydrocarbons (CHCs) are abundant in the superficial cuticular layer (envelope) of insects where they play roles as structural, anti-desiccation and semiochemical compounds. Many studies have investigated the CHC composition in the adult insects. However, studies on the profiles of these compounds during cuticle formation and differentiation are scarce and restrict to specific stages of a few insect species. We characterized the CHCs developmental profiles in the honeybee workers during an entire molting cycle (from pupal-to-adult ecdyses) and in mature adults (forager bees). Gas chromatography/mass spectrometry (GC/MS) analysis revealed remarkable differences in the relative quantities of CHCs, thus discriminating pupae, developing and newly-ecdysed adults, and foragers from each other. In parallel, the honeybee genome database was searched for predicted gene models using known amino acid sequences of insect enzymes catalyzing lipid desaturation (desaturases) or elongation (elongases) as queries in BLASTP analysis. The expression levels of six desaturase genes and ten elongase genes potentially involved in CHC biosynthesis were determined by reverse transcription and real time polymerase chain reaction (RT-qPCR) in the developing integument (cuticle and subjacent epidermis). Aiming to predict roles for these genes in CHC biosynthesis, the developmental profiles of CHCs and desaturase/elongase transcript levels were evaluated using Spearman correlation coefficient. This analysis pointed to differential roles for these gene products in the biosynthesis of certain CHC classes. Based on the assumption that homologous proteins may share a similar function, phylogenetic trees were reconstructed as an additional strategy to predict functions and evolutionary relationships of the honeybee desaturases and elongases. Together, these approaches highlighted the molecular complexity underlying the formation of the lesser known layer of the cuticular exoskeleton, the envelope. [Copyright &y& Elsevier]

Abstract: The exposure and toxicological data used in human health risk assessment are obtained from diverse and heterogeneous sources. Complex mixtures found on contaminated sites can pose a significant challenge to effectively assess the toxicity potential of the combined chemical exposure and to manage the associated risks. A data fusion framework has been proposed to integrate data from disparate sources to estimate potential risk for various public health issues. To demonstrate the effectiveness of the proposed data fusion framework, an illustrative example for a hydrocarbon mixture is presented. The Joint Directors of Laboratories Data Fusion architecture was selected as the data fusion architecture and Dempster–Shafer Theory (DST) was chosen as the technique for data fusion. For neurotoxicity response analysis, neurotoxic metabolites toxicological data were fused with predictive toxicological data and then probability-boxes (p-boxes) were developed to represent the toxicity of each compound. The neurotoxic response was given a rating of “low”, “medium” or “high”. These responses were then weighted by the percent composition in the illustrative F1 hydrocarbon mixture. The resulting p-boxes were fused according to DST's mixture rule of combination. The fused p-boxes were fused again with toxicity data for n-hexane. The case study for F1 hydrocarbons illustrates how data fusion can help in the assessment of the health effects for complex mixtures with limited available data. [Copyright &y& Elsevier]

Abstract: 1H NMR metabolomics and conventional ecotoxicity endpoints were used to examine the response of earthworms exposed to petroleum hydrocarbons (PHCs) in soil samples collected from a site that was contaminated with crude oil from a pipeline failure in the mid-1990s. The conventional ecotoxicity tests showed that the soils were not acutely toxic to earthworms (average survival ≥90%), but some soil samples impaired reproduction endpoints by >50% compared to the field control soil. Additionally, metabolomics revealed significant relationships between earthworm metabolic profiles (collected after 2 or 14 days of exposure) and soil properties including soil PHC concentration. Further comparisons by partial least squares regression revealed a significant relationship between the earthworm metabolomic data (collected after only 2 or 14 days) and the reproduction endpoints (measured after 63 days). Therefore, metabolomic responses measured after short exposure periods may be predictive of chronic, ecologically relevant toxicity endpoints for earthworms exposed to soil contaminants. [Copyright &y& Elsevier]

Abstract: Environmental compounds have been shown to promote epigenetic transgenerational inheritance of disease. The current study was designed to determine if a hydrocarbon mixture involving jet fuel (JP-8) promotes epigenetic transgenerational inheritance of disease. Gestating F0 generation female rats were transiently exposed during the fetal gonadal development period. The direct exposure F1 generation had an increased incidence of kidney abnormalities in both females and males, prostate and pubertal abnormalities in males, and primordial follicle loss and polycystic ovarian disease in females. The first transgenerational generation is the F3 generation, and the jet fuel lineage had an increased incidence of primordial follicle loss and polycystic ovarian disease in females, and obesity in both females and males. Analysis of the jet fuel lineage F3 generation sperm epigenome identified 33 differential DNA methylation regions, termed epimutations. Observations demonstrate hydrocarbons can promote epigenetic transgenerational inheritance of disease and sperm epimutations, potential biomarkers for ancestral exposures. [Copyright &y& Elsevier]

Abstract: Background: Subcutaneous administration of hydrocarbons, categorized according to their toxicological profiles, is rare compared to oral, inhalational, and cutaneous routes of exposure. Furthermore, injection of n-hexane in humans has not been described. Objectives: This report demonstrates a singular case of subcutaneous administration of n-hexane. Case Report: A 21-year-old man presented to the Emergency Department (ED) 7 h after injecting his left antecubital fossa with approximately 5 cc of spot remover fluid, which contained more than 95% n-hexane, in a suicide attempt. There was redness in the left forearm, but no apparent swelling was observed. He was administered tetanus prophylaxis and discharged with follow-up. However, the patient returned to the ED 14 h later, complaining of progression of the swelling around the injection site extending to the axilla. Significant volume of air in the soft tissue of the affected extremity was noted on both the radiograph and computed tomography scan; therefore, an immediate extensive incision and debridement of the diseased limb was performed. The postoperative course was uneventful, and a complete resolution of emphysema without any functional deficits was obtained for 5 months of follow-up. Conclusion: In patients suffering from n-hexane injection, initial physical examination findings may not be apparent. Thus, the patient must be monitored closely for evidence of a spread of subcutaneous gas with elevation and immobilization. If increase in tissue pressure or spread of gas is not prevented, as in our case, immediate incision and removal of the toxic substances should be planned. [Copyright &y& Elsevier]

The BRCA-1 protein is a tumor suppressor involved in repair of DNA damage. Epigenetic mechanisms contribute to its reduced expression in sporadic breast tumors. Through diet, humans are exposed to a complex mixture of xenobiotics and natural ligands of the aromatic hydrocarbon receptor (AhR), which contributes to the etiology of various types of cancers. The AhR binds xenobiotics, endogenous ligands, and many natural dietary bioactive compounds, including the phytoalexin resveratrol (Res). In estrogen receptor-α (ERα)-positive and BRCA-1 wild-type MCF-7 breast cancer cells, we investigated the influence of AhR activation with the agonist 2,3,7,8 tetrachlorobenzo(p)dioxin (TCDDI on epigenetic regulation of the BRCA-1 gene and the preventative effects of Res. We report that activation and recruitment of the AhR to the BRCA-1 promoter hampers 17β-estradiol (E2)-dependent stimulation of BRCA-1 transcription and protein levels. These inhibitory effects are paralleled by reduced occupancy of ERa, acetylated histone (AcH)-4, and AcH3K9. Conversely, the treatment with TCDD increases the association of mono-methylated-H3K9, DNA-methyltransferase-1 IDNMT1), and methyl-binding domain protein-2 with the BRCA-1 promoter and stimulates the accumulation of DNA strand breaks. The AhR-dependent repression of BRCA-1 expression is reversed by small interference for the AhR and DNMT1 or pretreatment with Res, which reduces TCDD-induced DNA strand breaks. These results support the hypothesis that epigenetic silencing of the BRCA-1 gene by the AhR is preventable with Res and provide the molecular basis for the development of dietary strategies based on natural AhR antagonists. [ABSTRACT FROM AUTHOR]

Static exposure experiments were conducted to assess the toxicity of dispersed Prudhoe Bay Crude Oil (PBCO) to embryos of the topsmelt (Atherinops affinis). Treatment with the dispersant COREXIT 9500 resulted in greater hydrocarbon concentrations in chemically enhanced water-accommodated fractions (CEWAFs) of oil, relative to the untreated water-accommodated fractions (WAFs). Topsmelt embryo development and survival to hatching was significantly inhibited in CEWAF tests while minimal effects on embryo–larval survival were observed in WAF tests. Increased hydrocarbon concentrations in the CEWAF tests caused cardiovascular and other abnormalities in developing topsmelt embryos. [Copyright &y& Elsevier]