Mutagenic Factors Research Articles

THE CONNECTION OF THE KARIOTYPE AND REVERSING ABILITY COWS OF THE UKRAINIAN BLACK AND WHEAT DAIRY BREEDS

The aim of research: Studing cariotype conducted cows of Ukrainian Black-and-White dairy breeds and installed corelation conection between cariotype instability and reproduction ability.
 Methods of research: Сytogenetic – analysis of metaphase plates, peripheral blood cells cows of Ukrainian Black-and-White dairy breeds, micronucleus test-reaction of the organism on mutagenic factors of different nature, zootechnical – analysis of reproductive properties of animals Ukrainian Black-and-White dairy breeds, statistical.
 Research result: Cariotype analis of Ukrainian Black-and-White dairy breeds (30 heads) farm husbandry “Progress +” showed the following results: control of spontaneous mytagenesis in cows wich was reserch showing quantitative and structural chromosomal aberation. Quantative chromosomal aberationwas find as aneuploidy. Aneuploidy was equal to 7,4% which does not exceed the limits of spontaneous chromosomal variability(1,5–8,3%), what is normal for animals of milk production breeds. Cellular frequency with asynchronous difference centroid chromosomal areas i population of cows at husbandry “Progress +” was 1,05% and did not exceed the spontaneous cytogenetic variability characteristic for the species Bostaurus. The share of metaphase plates with structural chromosomal abnormalities (chromosomal breaks) 2,6% equal to the level of spontaneous chromosomal variability for cows (0,17–11,1%). Cellular cell with micro nucleus and dual core lymphocytes was within the spontaneous level, characteristic of mammals, which were kept in the absence of direct genotoxic effects and amounted to 3.7‰ and 2.3‰, respectively. To install associate conection between chromosomal abnormalities and the reproductive ability of the studied cows was carried out a correlation analysis. Received coefficient between dual-core lymphocytes and age 1 calving (r = -0,9585) indicates a negative correlation with the strength of communication according to the Student's criteria isreliable at P > 0.99.
 Conclusions: Quantitative chromosomal aberrations (aneuploidy) were 7.4% which does not exceed the limit of spontaneous chromosomal variability, characteristic for animals breeds of milk production.
 The frequency of cells with asynchronous difference is established centroid chromosomal areas – 1,05% and a fraction of metaphase plates – 2,6% which corresponds to the level of spontaneous chromosomal variability in cattle.
 Detected сell frequency with micro nucleus and dual core lymphocytes which were within the spontaneous level, characteristic of mammals which are kept in the absence of direct genotoxic effects and amounted to 3.7‰ and 2.3‰.
 Was detected a negative correlation relationship between dual-core lymphocytes and age of the 1 calving (r = -0.9585, P > 0.99).

Tradescantia as a biomonitor for genotoxicity evaluation of diesel and biodiesel exhaust emissions

Biodiesel, an alternative energy source, is promoted as cleaner and safer than other fuel options due to its reported reduction of particulate and gaseous emissions (CO2, CO, and total hydrocarbons). However, its volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbon (PAHs) emissions are key to understanding its toxic, mutagenic and carcinogenic risk factors. This research was developed to assess the genotoxic impact of exhaust emissions using biodiesel from animal fat, palm oil and soybean oil blended with diesel (B80). Diluted exhaust gases were analyzed simultaneously for pollutant emissions and for toxicity using an exposure chamber called the BioToxMonitor, where Tradescantia pallida and a KU-20 clone were exposed to exhaust following Trad-MCN and Trad-SH bioassays. The results show differences in the emission compositions and considerable mutagenic potential among the three biodiesels tested, with palm oil biodiesel emissions being the least harmful, based on its low pollutant concentrations and the negative response in the TradSH bioassay. In contrast, the animal fat biodiesel and soybean oil biodiesel emissions were as toxic as the diesel emissions, being positive in both Trad bioassays. This could be related to the PAH and carbonyl concentrations found in the vehicular exhaust. The genotoxicity of diesel emissions was related to PM1 and the concentrations of both gas and particle PAHs concentrations, which were two times higher compared to the highest concentrations observed for biodiesel. The data suggest that micronucleus assays in Tradescantia pallida are more sensitive for gaseous pollutant exposure. This is the first reported study of biodiesel exhaust biomonitoring in situ and under controlled conditions inside an exposure chamber.

Correlates of rate heterogeneity in avian ecomorphological traits.

Heterogeneity in rates of trait evolution is widespread, but it remains unclear which processes drive fast and slow character divergence across global radiations. Here, we test multiple hypotheses for explaining rate variation in an ecomorphological trait (beak shape) across a globally distributed group (birds). We find low support that variation in evolutionary rates of species is correlated with life history, environmental mutagenic factors, range size, number of competitors, or living on islands. Indeed, after controlling for the negative effect of species' age, 80% of variation in species‐specific evolutionary rates remains unexplained. At the clade level, high evolutionary rates are associated with unusual phenotypes or high species richness. Taken together, these results imply that macroevolutionary rates of ecomorphological traits are governed by both ecological opportunity in distinct adaptive zones and niche differentiation among closely related species.

The Pathophysiology of Post-Traumatic Glioma.

Malignant glioma is a brain tumor with a very high mortality rate resulting from the specific morphology of its infiltrative growth and poor early detection rates. The causes of one of its very specific types, i.e., post-traumatic glioma, have been discussed for many years, with some studies providing evidence for mechanisms where the reaction to an injury may in some cases lead to the onset of carcinogenesis in the brain. In this review of the available literature, we discuss the consequences of breaking the blood–brain barrier and consequences of the influx of immune-system cells to the site of injury. We also analyze the influence of inflammatory mediators on the expression of genes controlling the process of apoptosis and the effect of chemical mutagenic factors on glial cells in the brain. We present the results of experimental studies indicating a relationship between injury and glioma development. However, epidemiological studies on post-traumatic glioma, of which only a few confirm the conclusions of experimental research, indicate that any potential relationship between injury and glioma, if any, is indirect.

A thermodynamic limit constrains complexity and primitive social function

AbstractThe evolutionary trend toward increasing complexity and social function is ultimately the result of natural selection's paradoxical tendency to foster cooperation through competition. Cooperating populations ranging from complex societies to somatic tissue are constantly under attack, however, by non-cooperating mutants or transformants, called ‘cheaters’. Structure in these populations promotes the formation of cooperating clusters whose competitive superiority can alone be sufficient to thwart outgrowths of cheaters and thereby maintain cooperation. But we find that when cheaters appear too frequently – exceeding a threshold mutation or transformation rate – their scattered outgrowths infiltrate and break up cooperating clusters, resulting in a cascading loss of social cohesiveness, a switch to net positive selection for cheaters and ultimately in the loss of cooperation. Our findings imply that a critically low mutation rate had to be achieved (perhaps through the advent of proofreading and repair mechanisms) before complex cooperative functions, such as those required for multicellularity and social behaviour, could have evolved and persisted. When mutation rate in our model is also allowed to evolve, the threshold is crossed spontaneously after thousands of generations, at which point cheaters rapidly invade. Probing extrapolations of these findings suggest: (1) in somatic tissue, it is neither social retro-evolution alone nor mutation rate evolution alone but the interplay between these two that ultimately leads to oncogenic transitions; the rate of this coevolution might thereby provide an indicator of lifespan of species, terrestrial or not; (2) the likelihood that extraterrestrial life can be expected to be multicellular and social should be affected by ultraviolet and other mutagenic factors.

Mutalisk: a web-based somatic MUTation AnaLyIS toolKit for genomic, transcriptional and epigenomic signatures.

Somatic genome mutations occur due to combinations of various intrinsic/extrinsic mutational processes and DNA repair mechanisms. Different molecular processes frequently generate different signatures of somatic mutations in their own favored contexts. As a result, the regional somatic mutation rate is dependent on the local DNA sequence, the DNA replication/RNA transcription dynamics and epigenomic chromatin organization landscape in the genome. Here, we propose an online computational framework, termed Mutalisk, which correlates somatic mutations with various genomic, transcriptional and epigenomic features in order to understand mutational processes that contribute to the generation of the mutations. This user-friendly tool explores the presence of localized hypermutations (kataegis), dissects the spectrum of mutations into the maximum likelihood combination of known mutational signatures and associates the mutation density with numerous regulatory elements in the genome. As a result, global patterns of somatic mutations in any query sample can be efficiently screened, thus enabling a deeper understanding of various mutagenic factors. This tool will facilitate more effective downstream analyses of cancer genome sequences to elucidate the diversity of mutational processes underlying the development and clonal evolution of cancer cells. Mutalisk is freely available at http://mutalisk.org.

MODERN MOLECULAR-GENETIC APPROACH TO INCREASE EFFICIENCY OF SELECTION PROCESS IN ANIMAL BREEDING OF UKRAINE

MODERN MOLECULAR-GENETIC APPROACH TO INCREASE EFFICIENCY OF SELECTION PROCESS IN ANIMAL BREEDING OF UKRAINE

HUMAN HEALTH HAZARD OF POLYCYCLIC AROMATIC HYDROCARBON IN ROAD DUST IN HA NOI METROPOLIS

This study investigates PAHs content in road dust of Hanoi metropolis, Vietnam. The samples were colected from the roads around city and analyzed by gas chromatography mass spectrometry (GC/MS). The total PAHs mass concentration ranges from 33.88 μg/kg to 5588,16 μg/kg, with the mean of 356,24 μg/kg in which HMW accounted up 70 % and LMW made up 30 %. The toxic equivalence factors (TEFs), mutagenic potency equivalent factors (MEFs) and the incremental lifetime cancer risk (ILCR) methodologies were applied to evaluate human exposure to carcinogenic PAHs sources. Carcinogenic equivalents (BaP-TEQ) and mutagenic equivalents (BaP-MEQ) were calculated from the potency relative to BaP (TEF) and BaP (MEF). The value of BaP-TEQ for 8 PAHs varied from 1.13 μg/kg to 195.23 μg/kg with mean of 24.34 μg/kg, while the value of BaP-MEQ ranged 1.45 μg/kg to 123.15 μg/kg with mean of 19.96 μg/kg. Basing on ILCRs model, the total cancer risk for children and adults was up to 1.6×10-5 and 3.9×10-5, posing a moderate potential cancer risk, respectively.

Neoplastic lymphangiosis of the upper aerodigestive tract simulating field cancerization: histopathological analysis, surgical limits and literature review.

Neoplastic lymphangiosis is defined as extensive embolic spread of cancer cells in the lymphatic vessels often without any evidence of a mass. Instead, field cancerization is defined by the presence of multifocal neoplastic lesions in a mucosal field previously exposed to mutagenic factors. In this case report, this oncological entity was suggested by the wide extent and multifocality of the disease and by the patient's exposure to risk factors. Instead, the pathological slides revealed the integrity of the mucosa and the presence of widespread embolic metastasis to lymphatic vessels. Thus, the diagnosis was changed to neoplastic lymphangiosis. This clinical presentation is a negative prognostic factor, and surgical treatment is ineffective because of the impossibility to obtain adequate free margins. The present case underlines the poor prognosis of such locally advanced cancer and the importance of recognizing it early so that the treatment approach can be adapted.

Antibiotic resistance mutations induced in growing cells of Bacillus-related thermophiles.

Stress-induced mutagenesis can assist pathogens in generating drug-resistant cells during antibiotic therapy; however, if and how antibiotics induce mutagenesis in microbes remains poorly understood. A non-pathogenic thermophile, Geobacillus kaustophilus HTA426, efficiently produces derivative cells resistant to rifampicin and streptomycin via rpoB and rpsL mutations, respectively. Here, we examined this phenomenon to suggest a novel mutagenic mode induced by antibiotics. Fluctuation analysis indicated that mutations occurred via spontaneous mutations during culture. However, mutations were much more frequent in growing cells than stationary cells, and mutation sites were varied through cell growth. These observations suggested that growing cells induced mutagenesis in response to antibiotics. An in-frame deletion of mfd, which governs transcription-coupled repair to correct DNA lesions on the transcribed strand, caused mutations that were comparable between growing and stationary cells; therefore, the mutagenic mechanism was attributable to DNA repair defects where growing cells depressed mfd function. Mutations occurred more frequently at optimal growth temperatures for G. kaustophilus than at a higher growth temperature, suggesting that the mutagenesis relies on active cellular activities rather than high temperature-associated DNA damage. In addition, the mutagenesis may involve a mutagenic factor targeting these sites, in addition to mfd depression, because rpoB and rpsL mutations were dominant at thymine and guanine sites on the transcribed strand. A similar mutagenic profile was observed for other Geobacillus and thermophilic Bacillus species. This suggests that Bacillus-related thermophiles commonly induce mutagenesis in response to rifampicin and streptomycin to produce resistant cells.

The Impact of the Serotonin on the Cause and Treatment of Cancer

This review article goes through many researches based on the effectiveness of the neurotransmitter serotonin on cancer cells and also the impact of SSRIs (selective serotonin reuptake inhibitors) drugs on the cause of certain types of cancers. Serotonin has been shown to be a mutagenic factor for a wide range of normal and tumor cells. Serotonin exhibits a growth stimulatory effect in aggressive cancers and carcinoids usually through 5- HT1 and 5-HT2 receptors. In contrast, low doses of serotonin can inhibit tumor growth via the decrease of blood supply to the tumor, suggesting that the role of serotonin on tumor growth is concentration-dependent. Serum serotonin level was found to be suitable for prognosis evaluation of urothelial carcinoma in the urinary bladder, adenocarcinoma of the prostate and renal cell carcinoma.The mechanism that connect serotonin with tumor evolution seem to be related to the serotonin impact on tumor associated macrophages.

Mutation accumulation under UV radiation in Escherichia coli

Mutations are induced by not only intrinsic factors such as inherent molecular errors but also by extrinsic mutagenic factors such as UV radiation. Therefore, identifying the mutational properties for both factors is necessary to achieve a comprehensive understanding of evolutionary processes both in nature and in artificial situations. Although there have been extensive studies on intrinsic factors, the mutational profiles of extrinsic factors are poorly understood on a genomic scale. Here, we explored the mutation profiles of UV radiation, a ubiquitous mutagen, in Escherichia coli on the genomic scale. We performed an evolution experiment under periodic UV radiation for 28 days. The accumulation speed of the mutations was found to increase so that it exceeded that of a typical mutator strain with deficient mismatch repair processes. The huge contribution of the extrinsic factors to all mutations consequently increased the risk of the destruction of inherent error correction systems. The spectrum of the UV-induced mutations was broader than that of the spontaneous mutations in the mutator. The broad spectrum and high upper limit of the frequency of occurrence suggested ubiquitous roles for UV radiation in accelerating the evolutionary process.

Identification of PMN-released mutagenic factors in a co-culture model for colitis-associated cancer.

Microsatellite instability (MSI) is present in ulcerative colitis (UC) and colitis-associated colorectal cancers (CAC). Certain factors released by polymorphonuclear cells (PMNs) may drive mucosal frameshift mutations resulting in MSI and cancer. Here, we applied a co-culture system with PMNs and colon epithelial cells to identify such culprit factors. Subjecting HCT116 + chr3 and human colonic epithelial cells (HCEC)-1CT MSI-reporter cell lines harboring mono-, di- or tetranucleotide DNA repeats linked to enhanced green fluorescent protein (EGFP) to activated PMNs induced frameshift mutations within all repeats, as quantified by flow cytometry. Activated PMNs released superoxide and hydrogen peroxide (H2O2), as measured by lucigenin-amplified chemiluminescence and fluorometry, respectively. Catalase, which scavenges H2O2, reduced such PMN-induced MSI. The NADPH-oxidase inhibitor apocynin, which blocks the oxidative burst in PMNs, similarly inhibited PMN-induced MSI. A bead-based multiplex assay revealed that PMNs release a wide range of cytokines such as interleukin (IL)-8, IL-6 and tumor necrosis factor-α (TNF-α). In vitro, these cytokines increased MSI in colon epithelial cells, and the Janus kinase (JAK) inhibitor tofacitinib abolished IL-6-induced or PMN-induced MSI. Intracellular reactive oxygen species (ROS) formation, as measured by 2’,7’–dichlorofluorescein diacetate (DCFDA) assay, was induced upon cytokine treatment. DNA oxidation upon IL-6 was present, as detected by formamidopyrimidine glycosylase (FPG)-modified comet assay. In conclusion, activated PMNs induce frameshift mutations in colon epithelial cells resulting in MSI. Both oxidative burst with release of ROS and PMN-secreted cytokines, such as IL-8, IL-6 or TNF-α, contribute to MSI. ROS scavengers and/or specific inhibitors of cytokine signaling may delay or prevent cancer development in the setting of colitis.

Evaluation of apoptosis induced by exposure to antineoplastic drugs in peripheral blood lymphocytes of nurses.

Cytostatic antineoplastic drugs are considered carcinogenic and mutagenic risk factors for health workers who are occupationally exposed to them; however, the molecular mechanisms underlying these effects remain to be elucidated. Therefore, the present study aimed to investigate the underlying mechanisms of antineoplastic drugs-induced apoptosis of peripheral blood lymphocytes (PBLs) obtained from oncology nurses handling antineoplastic drugs. A microRNA (miRNA/miR) polymerase chain reaction (PCR) array was performed to analyze the expression levels of miRNAs in the PBLs from 3 trained nurses occupationally exposed to antineoplastic drugs. The effects of miR-34a on cell proliferation and apoptosis in temozolomide (TMZ) treated PBLs were analyzed by cell counting kit-8 and flow cytometry assays. The protein expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, caspase-3 and caspase-9 were determined by western blot analysis, and miR-34a expression levels were detected using quantitative reverse transcription-PCR. The results of the present study demonstrated that miR-34a was significantly upregulated in oncology nurses that were occupationally exposed to antineoplastic drugs. In addition, TMZ suppressed cell proliferation and induced apoptosis, by promoting the expression of miR-34a, in a dose-dependent manner, and also inhibited the expression of Bcl-2. Furthermore, knockdown of miR-34a was able to reverse the reduction of cell proliferation and promotion of apoptosis induced by TMZ in PBLs. Together, these results indicated that abnormal expression of miR-34a may be considered a diagnostic marker in nurses occupationally exposed to antineoplastic drugs.

Polycyclic Aromatic Hydrocarbons (PAHs) Occurrence and Toxicity in Camellia sinensis and Herbal Tea

ABSTRACTThis study describes a survey of polycyclic aromatic hydrocarbon (PAH) concentrations in 23 green, herbal, and black tea brands widely consumed in Nigeria by determining the levels of benzo[a]pyrene, chrysene (PAH2), benzo[a]pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene (PAH4), benzo[a]pyrene, benz[a]anthracene, benzo[k]fluoranthene, chrysene, benzo[b]fluoranthene, dibenz[ah]anthracene, benzo[ghi]per-ylene and indeno[1,2,3-cd]pyrene (PA-H8). Toxic equivalence factor and mutagenic equivalence factor were applied to evaluate the toxic equivalence and mutagenic equivalence quotients relative to benzo[a]pyrene. The concentrations of PAHs indicate that Regulation 835/2011/EC was not fulfilled by benzo[a]anthracene, B[a]A, benzo[a]pyrene, B[a]P, benzo[b]fluoranthene, B[b]F, and chrysene, CHR. The PAH4 levels ranged from 1.28 to 44.57, 4.34 to 11.20, and 0.76 to 34.82 µg/kg in green, black, and herbal tea products, respectively. On the other hand, the PAH8 concentration varied between 1.63 and 65.73, 5.02 and 68.83, and 12.43 and 24.92 µg/kg in green, herbal, and black tea samples. The PAH4 and PAH8 provide more reliable indicators for determination of PAH contamination and risk characterization in food than PAH2.

The influence of mutagenic factors on F1M1 and M1 plants of bread winter wheat

Purpose. To determine the influence of mutagens on plant growth and development of hybrid progenies (F1M1) and varieties (M1) of winter wheat obtained from seeds treated. Methods. In 2006-2013, seeds of F1 hybrids and varieties were treated with chemical mutagens N-nitroso-N-ethyl-urea (NEU), N-nitroso-N-methyl urea (NMU), 1,4-bisdiazoacetylbutane (DAB), dimethyl sulfate (DMS) at various concentrations. Dry seeds were also irradiated with gamma rays at dose of 100 Gy. Results. In 2007, when treating seeds with NMU 0.025 %, germination in 52.2 % of hybrid combinations was significantly over control. In 2011, when treating seeds with mutagens (NEU 0.01 %, NMU 0.0125 %, DMS 0.0125 %), 57.8 % of hybrid combinations exceeded the control for field germination under predominantly stimulating action of the two mutagens (NEU 0.01 % and NMU 0.0125 %). A significantly high stimulating effect the mutagen DMS 0.05 % (in 2012) on field germination of hybrid seeds was detected in 67 % of combinations, while when treating seeds with DMS 0.0125 % (in 2011), it was only in 33 % of combinations. In 2012, among eight varieties which seeds were treated with DAB 0.05 % six of them showed the stimulating effect of the mutagen on field germination level. In the winter of 2007–2008, excess over the control overwintering level in hybrids after treatment with NEU 0.005 % and NMU 0.025% was noted (in 47.7 % and 54.5% of combinations resp.). In 2011–2012, when treating seeds with NEU 0.01 %, the overwintering level exceeded the control in 27 % of combinations, while when treating with the mutagens NMU 0.0125 % and DMS 0.0125 %, it did in 20 % of combinations. In 2012–2013, when treating hybrid seeds with the mutagens NEU 0.05 % and DMU 0.05 %, overwintering level of plants significantly exceeded the control in hybrid combinations Romantika / TAM 107 and Yermak / Demetra (the latter was submitted to State Variety Testing as the variety MIP Valensiia) and also in the varieties Demetra when treating with DMS 0.05 %, and Voloshkova (DAB 0.05 %). Phenological observations conducted in 2008, 2011 and 2012 showed that for the most of F1M1 hybrids and M1 varieties heading dates did not exceed 1–3 days earlier or later than in the control. However, in some cases there are deviations from the control for 7 and 5 days which are rather significantly. Conclusions. It was revealed either inhibiting or stimulating effects of chemical and physical mutagens on winter wheat hybrids and varieties. Depending on kind of mutagen, concentration and genotype, these effects occurred in the parameters of field germination, overwintering level and heading date of F1M1 and M1 plants grown from seeds treated with the mutagens.

Exploring background mutational processes to decipher cancer genetic heterogeneity.

Much remains unknown about the progression and heterogeneity of mutational processes in different cancers and their diagnostic and clinical potential. A growing body of evidence supports mutation rate dependence on the local DNA sequence context for various types of mutations. We propose several tools for the analysis of cancer context-dependent mutations, which are implemented in an online computational framework MutaGene. The framework explores DNA context-dependent mutational patterns and underlying somatic cancer mutagenesis, analyzes mutational profiles of cancer samples, identifies the combinations of underlying mutagenic processes including those related to infidelity of DNA replication and repair machinery, and various other endogenous and exogenous mutagenic factors. As a result, the combination of mutagenic processes can be identified in any query sample with subsequent comparison to mutational profiles derived from malignant and benign samples. In addition, mutagen or cancer-specific mutational background models are applied to calculate expected DNA and protein site mutability to decouple relative contributions of mutagenesis and selection in carcinogenesis, thus elucidating the site-specific driving events in cancer. MutaGene is freely available at https://www.ncbi.nlm.nih.gov/projects/mutagene/.

Matching decision method for knowledgeable manufacturing system and its production environment

To secure the quick response of knowledgeable manufacturing system (KMS) to the dynamic production environment and its desirable adaptability and competitiveness, we propose a matching decision method that is based on the improved support vector machine (ISVM for short), and the production environment. Taking into account the uncertainty and fuzziness of the production environment, the triangular fuzzy numbers are introduced to represent the uncertain input factors. Independent penalty coefficients are employed for different categories to address the problem of unbalanced samples. To meet the requirement for classifying small, uncertain input, and unbalanced samples, an improved SVM model based on triangular fuzzy theory is put forward. Considering the mutagenic factor and dynamic weight, we improve the particle swarm algorithm to optimize the model parameters. The matching categories of KMS and dynamic production environment are defined, and the corresponding matching decision method based on ISVM model is built. Case study shows that the proposed ISVM matching decision method is feasible and effective.

Concentrations and health risk assessment of Polycyclic aromatic hydrocarbons in Soils of an urban environment in the Niger Delta, Nigeria

The concentrations and compositional patterns of the United States Environmental Protection Agency (US EPA) 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in surface soils of an urban environment in the Niger Delta of Nigeria with a view to providing information on the sources, extent of contamination and human health risks of PAHs in these soils. The analyses were performed by means of gas chromatography-mass spectrometry (GC-MS) after extraction of the soils with hexane/dichloromethane and clean-up of the extracts. The concentration of Σ16 PAHs in the urban soils ranged from 188 to 684 µg kg−1, while the ΣPAH7c (carcinogenic PAHs) ranged from 28.5 and 571 µg kg−1. The estimated carcinogenic and mutagenic potency factors for these sites ranged from 2.34 to 197 and 9.66 to 195 µg kg−1 respectively. The composition of PAHs in these soils follows the order: 5-rings>4-rings>3-rings>6-rings>2-rings, and higher molecular weight PAHs accounted for a significant proportion of the Σ16 PAH concentration in this study. The results indicated that there is a high potential risk of cancer development as a result of exposure of PAHs via ingestion, dermal contact and inhalation. The diagnostic ratios indicate that the PAHs in these soils originated mainly from pyrogenic processes, such as combustion of petroleum, fossil fuels and biomass such as woods, charcoal straw and grasses. The results of this study provided information on the concentrations and compositional patterns of PAHs, which is useful in understanding the effects, sources, fate and transport of PAHs in soils, as well as environmental quality management and environmental forensic studies.

Optimization of Reactive Power Algorithm in Distribution Network Containing Wind Farm

A new strategy on reactive power optimization for power grid with wind farm integration is proposed. The mathematical model is built by using the optimal scenario analysis method and the modified particle swarm optimization algorithm (MPSO). The method about how to obtain the optimal scenarios is discussed. The optimal scenarios position for wind power is deduced based on the Wasserstein distance metric, and the occurrence probability is also studied simultaneously. In order to avoid falling into local optimum, the self-adapting mutagenic factor and mutation probability are designed in MPSO. Simulation examples show the effectiveness of MPSO. The mutagenic factor takes effect when the objective function value tends to be constant. Power loss and voltage stability margin are considered in the objective function. In initial phase of MPSO, the general particle swarm optimization algorithm (PSO) is processed, and this can guarantee the rapid convergence for the optimization procedure. After some iterations, the mutagenic factor begins to have an impact to ensure the global optimum can be obtained. The IEEE 69-bus distribution system is used to the experiment. In the experiment, the optimal scenarios position and scenario occurrence probability are worked out. Test results show that the new strategy is effective.