WorldWideScience

Sample records for bridged diphenyl acaricides

  1. Effect of acaricides on the activity of glutathione transferases from the parasitic mite Sarcoptes scabiei.

    Science.gov (United States)

    Molin, E U; Mattsson, J G

    2008-01-01

    Glutathione transferases (GSTs) are a family of multifunctional enzymes with fundamental roles in cellular detoxication. Here we report the molecular characterization of 3 recombinant GSTs belonging to the mu- and delta-class from the parasitic mite Sarcoptes scabiei. Kinetic constants were determined, and the effect of acaricides, including organothiophosphates, pyrethroid esters, a formamidine, a macrocyclic lactone, an organochlorine as well as a bridged diphenyl acaricide, on the activity of the GSTs were tested using 1-chloro-2,4-dinitrobenzene (CDNB) as model substrate. Our results showed that enzymes from the same class and with high amino acid sequence identity have significantly different kinetic properties. For instance, one mu-class GST lost more than 50% of its activity in the presence of one of the organothiophosphates while the activity of the second mu-class GST was only slightly reduced under identical conditions. Tertiary structure modulations indicated that structural differences were the crucial factor for the different kinetic patterns observed. Genome analysis showed that the two mu-class GSTs are organized in tandem in the S. scabiei genome. Taken together these results show that GSTs might be involved in the metabolism of acaricides in S. scabiei.

  2. Reactivity of some S-bridge containing diphenyl derivatives (sulfides, sulfoxides, sulfones) towards ortho-positronium atoms in dimethylsulfoxide solution

    Energy Technology Data Exchange (ETDEWEB)

    Levay, Bela [Department of Nuclear Chemistry, Eoetvoes Lorand University, Budapest (Hungary)], E-mail: levay@para.chem.elte.hu; Szabo, Denes [Department of Organic Chemistry, Eoetvoes Lorand University, Budapest (Hungary)

    2006-08-01

    The effect of changes in the chemical structure of organic sulfur compounds on their reactivity towards an ortho-positronium (o-Ps) atom was investigated by positron annihilation lifetime spectroscopy in dimethylsulfoxide solutions. S-bridge containing molecules with very similar structural frameworks were selected as model systems, such as, diphenyl sulfide, sulfoxide and sulfone, and their derivatives. The effect of the type of the S-bridge on the reactivity increased in the order of S < SO < SO{sub 2} in all groups of the compounds with similar substituents on their phenyl groups. The same trend was observed for the calculated excess positive charge on the sulfur atoms and the LUMO energies of the molecules too. As it was expected, electron-withdrawing substituents on the aromatic rings increased both the reactivity and the negative values of the LUMO energy of the molecules (COOH < NO{sub 2}) whereas those with electron-donating character (CH{sub 3}O) showed the opposite effect.

  3. Efficacy of chitosan supported organic acaricide extract from Melia ...

    African Journals Online (AJOL)

    PRISCILA FERNANDA

    2016-06-29

    Jun 29, 2016 ... these acaricides (individual practices of combat, without applying the ... methods of acaricide management) induces resistance strains, growth and strengthening the active principles managed. ..... Borges LMF (2003). In vitro ...

  4. Changes in acaricidal potency by introducing functional radicals and an acaricidal constituent isolated from Schizonepeta tenuifolia.

    Science.gov (United States)

    Yang, Ji-Yeon; Lee, Hoi-Seon

    2013-11-27

    The acaricidal potential of an active constituent isolated from Schizonepeta tenuifolia oil and its structurally related derivatives was evaluated using filter paper and impregnated cotton fabric disk bioassays against house dust and stored food mites. The acaricidal constituent of S. tenuifolia oil was isolated by chromatographic techniques and identified as 2-isopropyl-5-methylcyclohexanone by GC-MS, (1)H-, and (13)C NMR spectra. 2-Isopropyl-5-methylcyclohexanone was a potent acaricide against house dust and stored food mites, based on the LD50 values from the filter paper and impregnated cotton fabric disk bioassays, followed by 4-isopropylcyclohexanone, 2-isopropylidene-5-methylcyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, and benzyl benzoate. Furthermore, 4-isopropylcyclohexanone and 2-isopropyl-5-methylcyclohexanone, which were introduced on the isopropyl (C3H7) functional radical of the cyclohexanone skeleton, had the highest acaricidal potency. These results indicate that S. tenuifolia oil and 2-isopropyl-5-methylcyclohexanone structural analogues could be effective natural acaricides for managing house dust and stored food mites.

  5. Acaricide, fungicide and drug interactions in honey bees (Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Reed M Johnson

    Full Text Available BACKGROUND: Chemical analysis shows that honey bees (Apis mellifera and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects. METHODOLOGY/PRINCIPAL FINDINGS: Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17 while amitraz toxicity was mostly unchanged (1 of 15. The sterol biosynthesis inhibiting (SBI fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested. CONCLUSIONS/SIGNIFICANCE: Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication

  6. Acaricide, fungicide and drug interactions in honey bees (Apis mellifera).

    Science.gov (United States)

    Johnson, Reed M; Dahlgren, Lizette; Siegfried, Blair D; Ellis, Marion D

    2013-01-01

    Chemical analysis shows that honey bees (Apis mellifera) and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects. Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17) while amitraz toxicity was mostly unchanged (1 of 15). The sterol biosynthesis inhibiting (SBI) fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested. Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication appears to play an important role. Evidence of non-transivity, year-to-year variation

  7. Field efficacy of acaricides against Varroa destructor

    Science.gov (United States)

    Gracia, María Jesús; Moreno, Carlos; Ferrer, Montserrat; Sanz, Alfredo; Peribáñez, Miguel Ángel; Estrada, Rosa

    2017-01-01

    Field trials were conducted in Northeast Spain (Aragón) to evaluate the effectiveness of two acaricides against Varroa destructor. These experiments took into account the season of the year, apiary, colony, and developmental state and strength of the colony. The acaricides used were a synthetic (amitraz, Apivar®) and a natural (formulated from Api Life Var®, thymol oil and thymol alcohol) product. The treatments used in the present study reduce high infestations of V. destructor, although they do not eliminate the infestation. Similar efficacies between treatments were found. Nevertheless, the efficacy of a treatment depends on the apiary where applied. Moreover, the detected variability in the apiary and hive poses a challenge to the identification of the significant factors. Therefore, more field studies to assess efficacies in several apiaries are needed to obtain a better understanding of the effects of the applied treatments. PMID:28158303

  8. Field efficacy of acaricides against Varroa destructor.

    Science.gov (United States)

    Gracia, María Jesús; Moreno, Carlos; Ferrer, Montserrat; Sanz, Alfredo; Peribáñez, Miguel Ángel; Estrada, Rosa

    2017-01-01

    Field trials were conducted in Northeast Spain (Aragón) to evaluate the effectiveness of two acaricides against Varroa destructor. These experiments took into account the season of the year, apiary, colony, and developmental state and strength of the colony. The acaricides used were a synthetic (amitraz, Apivar®) and a natural (formulated from Api Life Var®, thymol oil and thymol alcohol) product. The treatments used in the present study reduce high infestations of V. destructor, although they do not eliminate the infestation. Similar efficacies between treatments were found. Nevertheless, the efficacy of a treatment depends on the apiary where applied. Moreover, the detected variability in the apiary and hive poses a challenge to the identification of the significant factors. Therefore, more field studies to assess efficacies in several apiaries are needed to obtain a better understanding of the effects of the applied treatments.

  9. Photodecomposition of an acaricide, fenazaquin, in aqueous alcoholic solution.

    Science.gov (United States)

    Bhattacharyya, Jayati; Banerjee, Hemanta; Bhattacharyya, Anjan

    2003-07-02

    Fenazaquin (I) is a new acaricide of the quinazoline class. The photodecomposition of I was studied in aqueous methanolic and 2-propanolic solution under UV light (30 h) and sunlight (70 h) separately. The photolytic half-lives in aqueous methanolic solution were found to be 17.1 h (UV) and 38.1 h (sunlight), whereas these were 12.9 h (UV) and 29.2 h (sunlight) for aqueous 2-propanolic solution; all followed a first-order reaction kinetics. Six photoproducts were obtained: beta-phenyl (p-tert-butyl) ethyl alcohol (II), 4-hydroxyquinazoline (III), p-tert-butyl vinyl benzene (IV), 2,4-dihydroxyquinazoline (V), phenyl (p-tert-butyl) acetic acid (VI), and 2-methyl-2-[4'-(2' '-hydroxyethyl)phenyl]propanoic acid (VII). Compounds VI and VII could be isolated only from aqueous 2-propanolic solution under sunlight irradiation. The major degradation products are formed as a result of cleavage of the ether bridge linking the quinazoline and phenyl ring systems of the molecule, oxidation of the tert-butyl substituent, and oxidation of the heterocyclic portion of the quinazoline ring. A probable mechanism of formation of the photoproducts is also suggested.

  10. Susceptibility of Varroa destructor (Acari: Varroidae) to synthetic acaricides in Uruguay: Varroa mites' potential to develop acaricide resistance.

    Science.gov (United States)

    Maggi, Matías Daniel; Ruffinengo, Sergio Roberto; Mendoza, Yamandú; Ojeda, Pilar; Ramallo, Gustavo; Floris, Iganazio; Eguaras, Martín Javier

    2011-04-01

    The purpose of this study was to estimate the acaricide susceptibility of Varroa destructor populations from Uruguay, which had never been exposed to synthetic acaricides. It was also to determine whether acaricide resistance to coumaphos occurred in apiaries in which acaricide rotation had been applied. Bioassays with acaricides against mite populations that had never been exposed to synthetic acaricides were performed, also against mite populations in which control failures with coumaphos had been reported. Additionally, coumaphos' effectiveness in honeybee colonies was experimentally tested. The lethal concentration that kills 50% of the exposed animals (LC(50)) for susceptible mite populations amounted to 0.15 μg/Petri dish for coumaphos and to less than 0.3 μg/Petri dish for the other acaricides. Coumaphos LC(50) was above 40 μg/Petri dish for resistant mites. The effectiveness of coumaphos in honeybee colonies parasitized by V. destructor ranged from 17.6% to 93.9%. LC(50) for mite populations susceptible to the most commonly applied miticides was determined, and the first case of coumaphos resistance recorded in Uruguay was established.

  11. Acaricidal activity of eugenol based compounds against scabies mites.

    Directory of Open Access Journals (Sweden)

    Cielo Pasay

    Full Text Available BACKGROUND: Human scabies is a debilitating skin disease caused by the "itch mite" Sarcoptes scabiei. Ordinary scabies is commonly treated with topical creams such as permethrin, while crusted scabies is treated with topical creams in combination with oral ivermectin. Recent reports of acaricide tolerance in scabies endemic communities in Northern Australia have prompted efforts to better understand resistance mechanisms and to identify potential new acaricides. In this study, we screened three essential oils and four pure compounds based on eugenol for acaricidal properties. METHODOLOGY/PRINCIPAL FINDINGS: Contact bioassays were performed using live permethrin-sensitive S. scabiei var suis mites harvested from pigs and permethrin-resistant S. scabiei var canis mites harvested from rabbits. Results of bioassays showed that clove oil was highly toxic against scabies mites. Nutmeg oil had moderate toxicity and ylang ylang oil was the least toxic. Eugenol, a major component of clove oil and its analogues--acetyleugenol and isoeugenol, demonstrated levels of toxicity comparable to benzyl benzoate, the positive control acaricide, killing mites within an hour of contact. CONCLUSIONS: The acaricidal properties demonstrated by eugenol and its analogues show promise as leads for future development of alternative topical acaricides to treat scabies.

  12. Phase diagrams of diphenyl- n-dodecane and diphenyl-diphenyl oxide- n-dodecane systems

    Science.gov (United States)

    Garkushin, I. K.; Kolyado, A. V.; Yakovlev, I. G.

    2016-08-01

    The phase equilibria in the binary diphenyl- n-dodecane and ternary diphenyl-diphenyl oxide- n-dodecane systems was studied by differential scanning calorimetry. The melting temperatures and eutectic compositions were determined. The physicochemical characteristics of eutectic alloys such as the flash point, density, and enthalpy of fusion were given. The kinematic viscosity of eutectic alloys was determined in the temperature range 25-50°C.

  13. Carvacrol as a potent natural acaricide against Dermanyssus gallinae.

    Science.gov (United States)

    Tabari, Mohaddeseh Abouhosseini; Youssefi, Mohammad Reza; Barimani, Alireza; Araghi, Atefeh

    2015-10-01

    Resistance to conventional synthetic pesticides has been widely reported in Dermanyssus gallinae in poultry production systems. Introducing novel acaricides to poultry industry today is more urgent than ever. Research in this field recently focused on plants and plant-derived compounds as acaricides. In the present study, acaricidal activity of three plant bioactive components, carvacrol, thymol, and farnesol, was assessed against D. gallinae and compared with synthetic pesticide permethrin. Mode of acaricidal action was determined by contact toxicity and fumigant toxicity bioassays. Except farnesol which did not cause any mortality, carvacrol and thymol were found to be toxic to D. gallinae with LD50 values of 1 and 3.15 μg/cm(3), respectively. Permethrin gave the LD50 value of 31.95 μg/cm(3) which was less efficient than carvacrol and thymol. In fumigant toxicity bioassay, mortality rate in carvacrol- and thymol-treated groups in closed method was significantly higher than the open one. On the other hand, permethrin exhibited poor fumigant toxicity as there was no statistically significant difference between mortality rate in open and closed methods. These findings revealed that mechanism of acaricidal activity of carvacrol and thymol but not permethrin was mainly due to fumigant action. Results of the present study suggested that carvacrol and thymol, especially carvacrol, can be developed as a novel potent bioacaricide against D. gallinae.

  14. Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    YANG Hui-zhi; HU Jun-hua; LI Qing; LI Hong-jun; LIU Hao-qiang; YAO Ting-shan; RAN Chun; LEI Hui-de

    2009-01-01

    Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus citri was tested in the laboratory.Four solvents were used to prepare crude extracts,petroleum ether,chloroform,ethyl acetate,and ethanol,among which ethanol was the most effective one.The results suggested that ethanol extracts of B.sessilicarpa had eminent acaricidal and ovicidal activities.Concentrated extracts were prepared using petroleum ether,chloroform,ethyl acetate,or distilled water as solvent.Mite mortality rates in the concentrated extracts by petroleum ether,chloroform,or distilled water were significantly lower than those by ethyl acetate.The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL-1,respectively.After liquid chromatography and thin layer chromatography,the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted.Fraction 2 was found to possess higher acaricidal and ovicidal activities.The mortality of eggs and adult mites were 85.83 and 63.07%,respectively.Moreover,fraction 2 showed moderate oviposition inhibition effect (0.8795) against P.citri when the used dose Was higher than 2.5 mg mL-1.

  15. The economic importance of acaricides in the control of phytophagous mites and an update on recent acaricide mode of action research

    NARCIS (Netherlands)

    Van Leeuwen, T.; Tirry, L.; Yamamoto, A.; Nauen, R.; Dermauw, W.

    2015-01-01

    Acaricides are one of the cornerstones of an efficient control program for phytophagous mites. An analysis of the global acaricide market reveals that spider mites such as Tetranychus urticae, Panonychus citri and Panonychus ulmi are by far the most economically important species, representing more

  16. Design, Synthesis, Acaricidal/Insecticidal Activity, and Structure-Activity Relationship Studies of Novel Oxazolines Containing Sulfone/Sulfoxide Groups Based on the Sulfonylurea Receptor Protein-Binding Site.

    Science.gov (United States)

    Yu, Xiuling; Liu, Yuxiu; Li, Yongqiang; Wang, Qingmin

    2016-04-20

    Enormous compounds containing sulfone/sulfoxide groups have been used in a variety of fields, especially in drug and pesticide design. To search for novel environmentally benign and ecologically safe pesticides with unique modes of action, a series of 2,4-diphenyl-1,3-oxazolines containing sulfone/sulfoxide groups as chitin synthesis inhibitors (CSIs) were designed and synthesized on the basis of the sulfonylurea receptor protein-binding site for CSIs. Their structures were characterized by (1)H and (13)C nuclear magnetic resonance and high-resolution mass spectrometry. The acaricidal and insecticidal activities of the new compounds were evaluated. It was found that most of the target compounds displayed wonderful acaricidal activities against spider mite (Tetranychus cinnabarinus) larvae and eggs. Especially compounds I-4, II-3, and II-4 displayed higher activities than commercial etoxazole at a concentration of 2.5 mg L(-1). Some target compounds exhibited insecticidal activities against lepidopteran pests. The present work demonstrated that these compounds containing sulfone/sulfoxide groups could be considered as potential candidates for the development of novel acaricides in the future.

  17. Acaricide resistance and resistance mechanisms in Tetranychus urticae populations from rose greenhouses in the Netherlands

    NARCIS (Netherlands)

    Khajehali, J.; Van Nieuwenhuyse, P.; Demaeght, P.; Tirry, L.; Van Leeuwen, T.

    2011-01-01

    BACKGROUND: Spider mites are important crop pests that rapidly develop resistance to acaricides. To investigate whether acaricide resistance is a threat to greenhouse rose culture in the Netherlands, the susceptibility of 15 strains of Tetranychus urticae was tested to several currently used acarici

  18. Acaricide resistance and resistance mechanisms in Tetranychus urticae populations from rose greenhouses in the Netherlands

    NARCIS (Netherlands)

    Khajehali, J.; Van Nieuwenhuyse, P.; Demaeght, P.; Tirry, L.; Van Leeuwen, T.

    2011-01-01

    BACKGROUND: Spider mites are important crop pests that rapidly develop resistance to acaricides. To investigate whether acaricide resistance is a threat to greenhouse rose culture in the Netherlands, the susceptibility of 15 strains of Tetranychus urticae was tested to several currently used

  19. Resistance to acaricides in Italian strains of Tetranychus urticae : toxicological and enzymatic assays

    NARCIS (Netherlands)

    Tirello, P.; Pozebon, A.; Cassanelli, S.; Van Leeuwen, T.; Duso, C.

    2012-01-01

    Problems with Tetranychus urticae are frequently reported in protected crops in Italy, particularly in roses where many introduced acaricides show a progressive loss of effectiveness. We have conducted bioassays to assess the response of some Italian strains of T. urticae to a number of acaricides.

  20. Stage-Specific Expression of Resistance to Different Acaricides in Four Field Populations of Tetranychus urticae (Acari: Tetranychidae).

    Science.gov (United States)

    Tang, Xiaofeng; Zhang, Youjun; Wu, Qingjun; Xie, Wen; Wang, Shaoli

    2014-10-01

    The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide crop pest. The resistance to commonly applied acaricides (in this report, "acaricide" refers to both acaricides and insecticides that are toxic to mites) has seriously impaired T. urticae control in the field. Here, the sensitivity of eggs, larvae, and adults of laboratory and field populations of T. urticae to various acaricides was investigated. Based on data obtained with an acaricide-sensitive laboratory strain collected in 2009, abamectin was the most toxic of the tested acaricides. For each acaricide, susceptibility was greatest for larvae, least for adults, and intermediate for eggs. The egg was the most sensitive stage to abamectin, bifenazate, and hexythiazox; the larva was the most sensitive stage to abamectin, hexythiazox, bifenazate, propargite, and chlorfenapyr; and the adult was the most sensitive stage to abamectin, bifenazate, and chlorfenapyr. Based on the results obtained with the acaricide-sensitive laboratory strain, acaricides were selected to test against eggs, larvae, and adults of four field populations of T. urticae from Beijing, China. Although the field populations differed in their resistance to the acaricides in laboratory bioassays, the eggs, larvae, and adults of the four populations were sensitive to bifenazate and highly resistant to abamectin. Field trials for control of T. urticae in Beijing, China, should be conducted with bifenazate and other acaricides rather than with abamectin. © 2014 Entomological Society of America.

  1. THE SYNTHESIS OF MODIFIED DIPHENYL OXIDE RESIN

    Institute of Scientific and Technical Information of China (English)

    MAOMingfei; LIUZhifang; 等

    2002-01-01

    Modified diphenyl oxide resin was synthesized by co-polymerization of unsaturated acid and diphenyl oxide derivants.And then modified bismaleimide resin and expoxide linear phenolic resin were added into modified diphenyl oxide resin to co-polymerized and modify once more.The system was applied in composites.Their properties wrer investigated and found that they met the requirements as a heat-resisting adhesive.

  2. Survival and behavioural response to acaricides of the coconut mite predator Neoseiulus baraki.

    Science.gov (United States)

    Lima, Debora B; Melo, José W S; Guedes, Raul N C; Siqueira, Herbert A A; Pallini, Angelo; Gondim, Manoel G C

    2013-07-01

    The coconut mite, Aceria guerreronis Keifer, is a major pest of coconut palm in the world. The control of this pest species is done through acaricide applications at short time intervals. However, the predators of this pest may also be affected by acaricides. Among the predators of A. guerreronis, Neoseiulus baraki (Athias-Henriot) has potential for biological control. The objective of this study was to assess the effect of acaricides on the survival and behavior of N. baraki. The survivorship of N. baraki was recorded in surface-impregnated arenas. Choice and no-choice behavioral bioassays were carried out using a video tracking system to assess the walking behavior of the predator under acaricide exposure. Although all acaricides negatively affected the survival of N. baraki, chlorfenapyr and azadirachtin caused lower effect than the other acaricides. No significant differences in walking behavior were observed under exposure to fenpyroximate, chlorfenapyr and chlorpyrifos on fully-contaminated arenas. Azadirachtin and chlorpyrifos caused repellence. Irritability was observed for all acaricides, except for abamectin. Chlorfenapyr was the most suitable product for managing the coconut mite because of its low effect on survival and behavior of N. baraki.

  3. Acaricidal and repellent activities of essential oil of Eucalyptus globulus against Dermanyssus gallinae (Acari: Mesostigmata

    Directory of Open Access Journals (Sweden)

    Dehghani-Samani Amir

    2015-07-01

    Full Text Available Introduction: By considering an increase in drug resistance against red mites, finding the nonchemical herbal acaricide against Dermanyssus gallinae (De Geer (Acari: Mesostigmata is necessary to kill them and to reduce the chemical resistance against chemical acaricides in this specie. Dermanyssus gallinae is a potential vector of the causal agent of several viral diseases such as Equine encephalitis and St. Louis encephalitis. It can be a vector of bacteria such as Salmonella spp., Mycobacterium spp. and Erysipelothrix rhusiopathiae. It is also known to cause itching dermatosis in humans. In this study acaricidal and repellent activities of essential oil of Eucalyptus globulus against Dermanyssus gallinae were studied. Methods: After extracting the essential oil, different concentrations of the plant extract were prepared. Then, acaricidal effect of different concentrations was tested on poultry red mite, Dermanyssus gallinae, by dropping 3-4 drops of essential oil on mites. Repellent activity of essential oil was tested by Y-tube olfactometer bioassay. After the test, total number of killed and repellent mites reported. Results: Concentration of 1:2 or 50% had more acaricidal effect on mites. Also essential oil of Eucalyptus globulus had repellent activity against red mites. Conclusion: This study showed that essential oil of Eucalyptus globulus had acaricidal and repellent activities against red mites. Hence it might be used as a herbal acaricide against it to kill and to reduce the chemical resistance in this specie.

  4. Resistance Selection of Tetranychus cinnabarinus to Three Acaricides and Its Management Strategy

    Institute of Scientific and Technical Information of China (English)

    HE Lin; ZHAO Zhi-mo; DENG Xin-ping; WANG Jin-jun; LIU Huai; LIU Ying-hong

    2003-01-01

    The effects of retarding resistance evolution of mixing and sequencing acaricides were studied based on the resistance selection of three acaricides to Tetranychus cinnabarinus in the laboratory. Tetranychus cinnabarinus was continuously selected with fenpropathrin, abamectin and pyridaban for 28, 30 and 31generations, respectively, and resistance factor increased to 65.6, 7.2 and 1.2 time, accordingly. Results of cross-resistance determination suggested that there were no cross-resistance existed among the three acaricides.Analysis of resistance selection and estimation of realized heritability (h2 ) of resistance to three single and two mixed acaricides showed that a mixture of fenpropathrin+abamectin would slow resistance development compared with a sequence of fenpropathrin followed by abamectin while the mixture of pyridaben+abamectin and the sequence of pyridaben followed by abamectin would effectively retard resistance evolution.

  5. effect of a microbial-based acaricidal product on spotted and ...

    African Journals Online (AJOL)

    Administrator

    EFFECT OF A MICROBIAL-BASED ACARICIDAL PRODUCT ON SPOTTED ... reproductive potential and short life cycle facilitate rapid resistance ... This product is currently used in the .... abamectin (5 or 7 ppm), we observed faster decline.

  6. Spirodiclofen Derivatives as Highly Potential Acaricides:Synthesis, Structure and Bioactivity

    Institute of Scientific and Technical Information of China (English)

    FENG Xian-guo; XU Liang-zhong; KONG Fan-rui; LI Hong-xin; YIN Rui-feng

    2011-01-01

    A series of new compounds as highly potential acaricides was synthesized based on the structure of spirodiclofen.Their structures were identified by 1H NMR spectroscopy and element analysis.The bioassay indicated that most of the compounds exhibited excellent acaricidal activities,what's more,the bioactivities of some new compounds were better than that of the commercial spirodiclofen at a concentration of 20 μg/mL.The relationship between structure and biological activity was also discussed.

  7. Comparative toxicities of novel and conventional acaricides against different stages

    Directory of Open Access Journals (Sweden)

    Sapana Kumari

    2017-04-01

    Full Text Available Adulticidal, ovicidal and nymphicidal effects of different newer acaricides along with some conventional one were evaluated on the life stages of a susceptible laboratory strain of two-spotted spider mite (TSMM, Tetranychus urticae Koch (Acarina: Tetranychidae using a spray method. Abamectin was found to be the most toxic to the adults (LC50 = 0.39 ppm followed by fenpyroximate (5.67 ppm, spiromesifen (12.53 ppm, chlorfenapyr (32.24 ppm, propargite (77.05 ppm and dicofol (146.65 ppm. Hexythiazox was least toxic. There was no egg hatching when eggs were sprayed with one third of the recommended concentration of spiromesifen. This was statistically significantly different from all other treatments (fenpyroximate, chlorfenapyr, propargite, dicofol and hexythiazox which were, however, at par with each other. Based on the 10th day observations, the ovicidal activity of spiromesifen (100% was followed by dicofol (7.78% egg mortality and hexythiazox (6.67%. Almost no effect on hatching was observed in both abamectin and chlorfenapyr treatment (0.54%. In case of propargite, all the treated eggs hatched. Abamectin resulted in highest nymphal mortality (96.05% followed by dicofol (94.51%, hexythiazox (90.24 propargite (90.00, chlorfenapyr (89.33 and fenpyroximate (86.84% and all the treatments were at par with each other and statistically different from the control. The present study revealed that abamectin, spiromesifen, hexythiazox, fenpyroximate and chlorfenapyr acaricides can alternatively be used for effective management of the mites.

  8. Acaricidal properties of Ricinus communis leaf extracts against organophosphate and pyrethroids resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Ghosh, Srikanta; Tiwari, Shashi Shankar; Srivastava, Sharad; Sharma, Anil Kumar; Kumar, Sachin; Ray, D D; Rawat, A K S

    2013-02-18

    Indian cattle ticks have developed resistance to commonly used acaricides and an attempt has been made to formulate an ecofriendly herbal preparation for the control of acaricide resistant ticks. A 95% ethanolic extract of Ricinus communis was used to test the efficacy against reference acaricide resistant lines by in vitro assay. In in vitro assay, the extract significantly affects the mortality rate of ticks in dose-dependent manner ranging from 35.0 ± 5.0 to 95.0 ± 5.0% with an additional effect on reproductive physiology of ticks by inhibiting 36.4-63.1% of oviposition. The leaf extract was found effective in killing 48.0, 56.7 and 60.0% diazinon, deltamethrin and multi-acaricide resistant ticks, respectively. However, the cidal and oviposition limiting properties of the extract were separated when the extract was fractionated with hexane, chloroform, n-butanol and water. The HPTLC finger printing profile of R. communis leaf extract under λ(max.) - 254 showed presence of quercetin, gallic acid, flavone and kaempferol which seemed to have synergistic acaricidal action. In vivo experiment resulted in 59.9% efficacy on Ist challenge, however, following 2nd challenge the efficacy was reduced to 48.5%. The results indicated that the 95% ethanolic leaf extract of R. communis can be used effectively in integrated format for the control of acaricide resistant ticks.

  9. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  10. Acaricide resistance and strategies to mitigate economic impact of the southern cattle fever tick (Rhipicephalus microplus) on livestock production systems in the Americas

    Science.gov (United States)

    BACKGROUND: The southern cattle fever tick (SCFT), Rhipicephalus microplus, is considered the most economically important external parasite of livestock worldwide. SCFT populations resistant to acaricides complicate efforts to enhance the productivity of livestock. Here, acaricide resistance is summ...

  11. Effect of acaricidal components isolated from lettuce (Lactuca sativa) on carmine spider mite (Tetranychus cinnabarinus Boisd.).

    Science.gov (United States)

    Li, M; Zhang, Y; Ding, W; Luo, J; Li, S; Zhang, Q

    2017-08-14

    This study aimed to evaluate the acaricidal activity of lettuce (Lactuca sativa) extracts against carmine spider mites (Tetranychus cinnabarinus Boisd.) and isolate the acaricidal components. Acaricidal activities of lettuce extracts isolated from different parts (the leaf, root and seed) using various solvents (petroleum ether, acetone and methanol) were evaluated with slide-dip bioassay and relatively high median lethal concentration (LC50) values were detected. Acetone extracts of lettuce leaves harvested in July and September were fractionated and isolated with silica gel and thin-layer chromatography. Consequently, acetone extracts of lettuce leaves harvested in July exhibited higher acaricidal activity than those harvested in September, with an LC50 value of 0.268 mg ml-1 at 72 h post-treatment. A total of 27 fractions were obtained from the acetone extract of lettuce leaves harvested in July, and mite mortalities with the 11th and 12th fractions were higher than those with the other 25 fractions (LC50: 0.751 and 1.258 mg ml-1 at 48 h post-treatment, respectively). Subsequently, active acaricidal components of the 11th fraction were identified by infrared, nuclear magnetic resonance and liquid chromatography/mass spectrometry. Five components were isolated from the 11th fraction, with components 11-a and 11-b showing relatively high acaricidal activities (LC50: 0.288 and 0.114 mg ml-1 at 48 h post-treatment, respectively). Component 11-a was identified as β-sitosterol. In conclusion, acetone extracts of lettuce leaves harvested in July might be used as a novel phytogenic acaricide to control mites.

  12. The economic importance of acaricides in the control of phytophagous mites and an update on recent acaricide mode of action research.

    Science.gov (United States)

    Van Leeuwen, Thomas; Tirry, Luc; Yamamoto, Atsushi; Nauen, Ralf; Dermauw, Wannes

    2015-06-01

    Acaricides are one of the cornerstones of an efficient control program for phytophagous mites. An analysis of the global acaricide market reveals that spider mites such as Tetranychus urticae, Panonychus citri and Panonychus ulmi are by far the most economically important species, representing more than 80% of the market. Other relevant mite groups are false spider mites (mainly Brevipalpus), rust and gall mites and tarsonemid mites. Acaricides are most frequently used in vegetables and fruits (74% of the market), including grape vines and citrus. However, their use is increasing in major crops where spider mites are becoming more important, such as soybean, cotton and corn. As revealed by a detailed case study of the Japanese market, major shifts in acaricide use are partially driven by resistance development and the commercial availability of compounds with novel mode of action. The importance of the latter cannot be underestimated, although some compounds are successfully used for more than 30 years. A review of recent developments in mode of action research is presented, as such knowledge is important for devising resistance management programs. This includes spirocyclic keto-enols as inhibitors of acetyl-CoA carboxylase, the carbazate bifenazate as a mitochondrial complex III inhibitor, a novel class of complex II inhibitors, and the mite growth inhibitors hexythiazox, clofentezine and etoxazole that interact with chitin synthase I.

  13. Comparative toxicity of acaricides to honey bee (Hymenoptera: Apidae) workers and queens.

    Science.gov (United States)

    Dahlgren, Lizette; Johnson, Reed M; Siegfried, Blair D; Ellis, Marion D

    2012-12-01

    Acaricides are used to treat honey bee (Apis mellifera L.) colonies to control the varroa mite (Varroa destructor Anderson & Trueman), a worldwide threat to honey bee health. Although acaricides control a serious honey bee parasite and mitigate bee loss, they may cause harm to bees as well. We topically applied five acaricides, each with a different mode of action, to young adult queen and worker bees to generate dose-response curves and LD50. Twenty-four hours after treatment, queens were found to be three-times more tolerant of tau-fluvalinate and six-times more tolerant of thymol than workers when adjusted for body weight differences between workers (108 mg) and queens (180 mg). Queens survived the highest administered doses of fenpyroximate (1620 microg/g) and coumaphos (2700 microg/g) indicating that queens are at least 11-fold more tolerant of coumaphos and at least 54-fold more tolerant of fenpyroximate than workers. However, queens treated with as little as 54 microg/g of fenpyroximate exhibited reduced survival over 6 wk after treatment. Amitraz was the only acaricide tested for which queens were not more tolerant than workers. The striking difference in acaricide tolerance of queen and worker honey bees suggests physiological differences in how the two castes are affected by xenobiotics.

  14. Mitigation of Resistance Through Mixtures of Traditional Pesticides, Anti-tick Vaccines, and New Acaricides Developed by the Pharmaceutical Industry

    Science.gov (United States)

    Over the past 70 years, the southern cattle tick, Rhipicephalus (Boophilus) microplus, has developed resistance to every acaricide available for its control. Recently, populations of R. microplus have evolved simultaneous resistance to multiple classes of acaricides. These multi-resistant population...

  15. Photodegradation of the acaricide abamectin: a kinetic study.

    Science.gov (United States)

    Escalada, Juan Pablo; Gianotti, José; Pajares, Adriana; Massad, Walter A; Amat-Guerri, Francisco; García, Norman A

    2008-08-27

    The acaricide abamectin is a mixture of two colorless homologues in a molar ratio of at least 4:1 with the same structure of macrocyclic lactone. The kinetics of its degradation under direct (254 nm) and dye-sensitized (>400 nm) photoirradiation in methanol solution has been studied by UV-vis spectrophotometry, potentiometric detection of dissolved oxygen, stationary fluorescence, laser flash photolysis, and time-resolved detection of singlet molecular oxygen (O2((1)Delta(g))) phosphorescence. The results indicate that the degradation is very efficient under direct irradiation with UV light (254 nm), with a quantum yield of 0.23. On the contrary, under visible-light irradiation, using the natural pigment riboflavin or the synthetic dye rose bengal as sensitizers, the degradation is very inefficient and proceeds through a O2((1)Delta(g))-mediated mechanism, with a bimolecular rate constant for the overall O2((1)Delta(g)) quenching (the sum of physical and chemical quenching) of 5.5 x 10(5) M(-1) s(-1). This value is similar to those reported for the rate constants of the reactions of O2((1)Delta(g)) with isolated double bonds or conjugated dienes and points to similar processes in the case of abamectin.

  16. POLYBROMINATED DIPHENYL ETHERS IN SOUTHERN MISSISSIPPI CATFISH

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in a wide variety of consumer products. Concerns surrounding these compounds are primarily due do their ubiquitous presence in the environment as well as in human tissue, such as milk, coupled with evidence indi...

  17. Synthesis, insecticidal, and acaricidal activities of novel 2-aryl-pyrrole derivatives containing ester groups.

    Science.gov (United States)

    Zhao, Yu; Li, Yongqiang; Ou, Xiaoming; Zhang, Pengxiang; Huang, Zhiqiang; Bi, Fuchun; Huang, Runqiu; Wang, Qingmin

    2008-11-12

    A series of novel 2-aryl-pyrrole derivatives containing ester groups were synthesized, and their structures were characterized by (1)H NMR spectroscopy and elemental analysis. The insecticidal activities against oriental armyworm, mosquito, diamondback moth, green rice leafhopper, and bean aphids and acaricidal activities against spider mite of these new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal and acaricidal activities. The insecticidal activities against oriental armyworm of compounds IVa, IVd, IVe, IVf, IVg, IVi, IVk, and IVp were equal to commercialized Chlorfenapyr, and the insecticidal activities of most of compounds IVb, IVc, IVd, IVf, IVg, IVj, IVk, IVl, IVs, IVt, IVu, IVw, IVx, IVz, and Chlorfenapyr against mosquito at 0.10 mg kg (-1) were 100%, and the acaricidal activities of compounds IVd, IVe, IVf, IVg, IVh, IVi, and IVk were equal or superior to Chlorfenapyr. Especially, the results indicated that the acaricidal activity of [4-bromo-2-(4-chlorophenyl)-3-cyano-5-(trifluoromethyl)pyrrol-1-yl]methyl 3-methylbutanoate ( IVg) against spider mite was 2.65-fold as high as that of Chlorfenapyr from the value of LC 50.

  18. Acaricide efficiency of amitraz / cypermethrin and abamectin pour-on preparations in game

    Directory of Open Access Journals (Sweden)

    J.S. Van der Merwe

    2005-09-01

    Full Text Available The efficacy of an amitraz / cypermethrin pour-on preparation (1 % w/v each was tested against natural tick infestations of buffaloes, eland and blesbok in three separate trials. The eland were also treated with a 0.02 % abamectin (w/v acaricidal pour-on preparation. The amitraz / cypermethrin pour-on was effective against Amblyomma hebraeum, Rhipicephalus evertsi evertsi, Rhipicephalus appendiculatus and Hyalomma marginatum rufipes on the buffaloes. Both acaricides were effective against R. appendiculatus and Rhipicephalus (Boophilus decoloratus in the eland. The amitraz / cypermethrin acaricide was effective against R. (Boophilus decoloratus in the blesbok. Ticks can cause damage to the skins, secondary infections, abscesses, anaemia, loss of condition, tick toxicosis and act as vectors of infectious diseases. Introduction of hosts and / or ticks from endemic to non-endemic areas because of translocation of game, may lead to severe losses. The pouron acaricides tested were effective against natural tick infestations and should always be used according to the manufacturer's instructions and efficacy claims.

  19. Acaricide efficiency of amitraz/cypermethrin and abamectin pour-on preparations in game.

    Science.gov (United States)

    Van Der Merwe, J S; Smit, F J; Durand, A M; Krüger, L P; Michael, L M

    2005-12-01

    The efficacy of an amitraz/cypermethrin pour-on preparation (1% w/v each) was tested against natural tick infestations of buffaloes, eland and blesbok in three separate trials. The eland were also treated with a 0.02% abamectin (w/v) acaricidal pour-on preparation. The amitraz/cypermethrin pour-on was effective against Amblyomma hebraeum, Rhipicephalus evertsi evertsi, Rhipicephalus appendiculatus and Hyalomma marginatum rufipes on the buffaloes. Both acaricides were effective against R. appendiculatus and Rhipicephalus (Boophilus) decoloratus in the eland. The amitraz/cypermethrin acaricide was effective against R. (Boophilus) decoloratus in the blesbok. Ticks can cause damage to the skins, secondary infections, abscesses, anaemia, loss of condition, tick toxicosis and act as vectors of infectious diseases. Introduction of hosts and/or ticks from endemic to non-endemic areas because of translocation of game, may lead to severe losses. The pouron acaricides tested were effective against natural tick infestations and should always be used according to the manufacturer's instructions and efficacy claims.

  20. The effect of alternative acaricides on honey quality in organic beekeeping

    OpenAIRE

    Falcão, Soraia; Álvares, R.; Barros, Lillian; Vilas-Boas, Miguel

    2006-01-01

    The use of acaricides in organic beekeeping is legally restricted to essential oils find some organic acid since no synthetic compound can be added to the honey matrix. Thymoll, formic and oxalic acid are the main alternatives to control varroa mite, used all over the world with good results.

  1. Immune-related gene expression in nurse honey bees (Apis mellifera) exposed to synthetic acaricides.

    Science.gov (United States)

    Garrido, Paula Melisa; Antúnez, Karina; Martín, Mariana; Porrini, Martín Pablo; Zunino, Pablo; Eguaras, Martín Javier

    2013-01-01

    The mite Varroa destructor is an ectoparasite affecting honey bees worldwide. Synthetic acaricides have been among the principal tools available to beekeepers for its control, although several studies have shown its negative effects on honey bee physiology. Recent research suggests that those molecules strongly impact on immune signaling cascades and cellular immunity. In the present work, LC(50) in six-day-old bees were determined for the following acaricides: tau-fluvalinate, flumethrin, amitraz and coumaphos. According to this obtained value, a group of individuals was treated with each acaricide and then processed for qPCR analysis. Transcript levels for genes encoding antimicrobial peptides and immune-related proteins were assessed. Flumethrin increased the expression of hymenoptaecin when comparing treated and control bees. Significant differences were recorded between coumaphos and flumethrin treatments, while the first one reduced the expression of hymenoptaecin and abaecin, the last one up-regulated their expressions. No significant statistically changes were recorded in the expression levels of vitellogenin, lysozyme or glucose dehydrogenase among bees treated with acaricides and control bees. This work constitutes the first report, under laboratory conditions, about induction of immune related genes in response to synthetic miticides. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Increased transcription of Glutathione S-transferases in acaricide exposed scabies mites

    Directory of Open Access Journals (Sweden)

    Currie Bart J

    2010-05-01

    Full Text Available Abstract Background Recent evidence suggests that Sarcoptes scabiei var. hominis mites collected from scabies endemic communities in northern Australia show increasing tolerance to 5% permethrin and oral ivermectin. Previous findings have implicated detoxification pathways in developing resistance to these acaricides. We investigated the contribution of Glutathione S-transferase (GST enzymes to permethrin and ivermectin tolerance in scabies mites using biochemical and molecular approaches. Results Increased in vitro survival following permethrin exposure was observed in S. scabiei var. hominis compared to acaricide naïve mites (p in vitro permethrin susceptibility, confirming GST involvement in permethrin detoxification. Assay of GST enzymatic activity in mites demonstrated that S. scabiei var. hominis mites showed a two-fold increase in activity compared to naïve mites (p S. scabiei var. canis- mu 1 (p S. scabiei var. hominis mites collected from a recurrent crusted scabies patient over the course of ivermectin treatment. Conclusions These findings provide further support for the hypothesis that increased drug metabolism and efflux mediate permethrin and ivermectin resistance in scabies mites and highlight the threat of emerging acaricide resistance to the treatment of scabies worldwide. This is one of the first attempts to define specific genes involved in GST mediated acaricide resistance at the transcriptional level, and the first application of such studies to S. scabiei, a historically challenging ectoparasite.

  3. Acaricidal activity of active constituent isolated in Chamaecyparis obtusa leaves against Dermatophagoides spp.

    Science.gov (United States)

    Jang, Young-Su; Lee, Chi-Hoon; Kim, Moo-Key; Kim, Jeong-Hak; Lee, Sang-Hyun; Lee, Hoi-Seon

    2005-03-23

    Acaricidal activities of materials derived from Chamaecyparis obtusa leaves against Dermatophagoides farinae and Dermatophagoides pteronyssinus were examined using the dry film method and compared with that of commercial benzyl benzoate and N,N-diethyl-m-toluamide (DEET). The active constituent of the C. obtusa leaves was identified as beta-thujaplicin (C10H12(O2)) by spectroscopic analyses. Responses varied with dose. On the basis of a 24 h LC50 value, acaricidal activity against D. farinaewas more pronounced with beta-thujaplicin (72.2 mg/m2) than benzyl benzoate (89.9 mg/m2) and DEET (377 mg/m2). Acaricidal activity against D. pteronyssinus was more pronounced in beta-thujaplicin (62.1 mg/m2) than benzyl benzoate (72.4 mg/m2) and DEET (193 mg/m2). These results indicate that acaricidal activity of C. obtusa leaves likely results from by beta-thujaplicin. Beta-thujaplicin merits further study as potential house dust mite control agents or lead compounds.

  4. Application of ethnobotanical repellents and acaricides in prevention, control and management of livestock ticks: A review.

    Science.gov (United States)

    Pavela, Roman; Canale, Angelo; Mehlhorn, Heinz; Benelli, Giovanni

    2016-12-01

    Ticks transmit at least the same number or even more pathogens than any other group of blood-feeding arthropods worldwide affecting humans and animals. The eco-friendly control and management of tick vectors in a constantly changing environment is a crucial challenge. Besides the development of vaccines against ticks, IPM practices aimed at reducing tick interactions with livestock, emerging pheromone-based control tools, and few biological control agents, the extensive employment of acaricides and tick repellents still remain the most effective and ready-to-use strategies. However, the former is limited by the development of growing resistances as well as environmental concerns. Exploiting plants and plant products as sources of effective tick repellents and acaricides represents a promising strategy. In this scenario, the preservation of ethnobotanical information on repellent and acaricidal potential of plants is crucial. Here, we evaluated relevant information published in recent years, focused on plants used as repellents and acaricides against tick vectors in different regions worldwide. We selected a total of 238 plant species, which are traditionally used against ticks by native and local communities of Africa (Kenya, Uganda, Zimbabwe, South Africa), Europe (Serbia, Macedonia, Romania), Asia (Pakistan, India) and America (Brazil, Canada), from 56 families. However, only 7 families (i.e. Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae, Meliaceae, Apocynaceae and Solanaceae) represent the major quote (46%) of all plant species. We evaluated the differences in acaricidal and repellent efficacy of different formulations used. In the final section, implications arising from the surveyed anti-tick ethnobotanical knowledge and challenges for its future are discussed.

  5. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  6. Tools to fiht ticks: A never-ending story? News from the front of green acaricides and photosensitizers

    Directory of Open Access Journals (Sweden)

    Giovanni Benelli

    2016-08-01

    Full Text Available Nowadays, parasitology is facing a number of crucial challenges, including the urgent request of effective control tools against arthropod vectors of medical and veterinary importance. Ticks transmit at least the same amount or even more pathogen species than any other group of blood-feeding arthropods worldwide affecting humans and animals. Besides the development of vaccines against viruses vectored by ticks, integrated pest management practices aimed at reducing tick interactions with livestock, emerging pheromone-based control tools, and few biological control agents have been also proposed. The extensive employ of acaricides and tick repellents still remains the two most effective and ready-to-use strategies. However, the use of synthetic acaricides is limited by the development of resistance in several tick species as well as by heavy environmental concerns. In this scenario, the exploitation of botanicals as cheap and effective sources of tick repellents may represent a valid alternative, and the preservation of ethnobotanical information on the repellent and acaricidal potential of plants is crucial. On the other hand, novel photodynamic acaricides have been recently described, with a toxicity against ticks which far exceed some of the acaricides currently marketed (e.g. tetramethrin. In this brief review, I provide a focus on some hot news in tick control, with special reference to tick repellents of botanical origin and new photodynamic fluorescent acaricides. To my mind, knowledge on both the mentioned research issues may help researchers to build valuable roadmaps to boost tick control programs worldwide.

  7. Integrated control of an acaricide-resistant strain of the cattle tick Rhipicephalus microplus by applying Metarhizium anisopliae associated with cypermethrin and chlorpyriphos under field conditions.

    Science.gov (United States)

    Webster, Anelise; Reck, José; Santi, Lucélia; Souza, Ugo A; Dall'Agnol, Bruno; Klafke, Guilherme M; Beys-da-Silva, Walter O; Martins, João Ricardo; Schrank, Augusto

    2015-01-30

    The efficacy of the fungus Metarhizium anisopliae to control ticks has been shown in several in vitro experiments. However, few studies have been undertaken in field conditions in order to demonstrate the applicability of its use as a biological control of ticks and its combination with chemical acaricides. The aim of the present study was to evaluate the efficacy of M. anisopliae to control an acaricide-resistant strain of Rhipicephalus microplus under laboratory and field conditions. First, the compatibility of M. anisopliae strain (TIS-BR03) with commercial acaricides and its potential to control the cattle tick were evaluated in vitro. In general, acaricide treatments had mild effects on fungus viability. In the field experiment, the median of treatment efficacy with acaricide only, M. anisopliae only and combination of M. anisopliae with acaricide were 71.1%, 56.3% and 97.9%, respectively. There is no statistical difference between groups treated with M. anisopliae and acaricide alone. Thus, in this work we have demonstrated the applicability of M. anisopliae use associated or not with chemical acaricides on field conditions in order to control an acaricide-resistant strain of the cattle tick R. microplus.

  8. Determination of acaricides in honey by high-performance liquid chromatography with photodiode array detection.

    Science.gov (United States)

    Martel, Anne-Claire; Zeggane, Sarah

    2002-04-19

    Rapid analytical methods are described to control quality of honeys, concerning residues of acaricides applied in hives to prevent Varroa jacobsoni infestation. A liquid-liquid extraction with hexane-propanol-2-ammonia (60 ml:30 ml:0.28%) was used for the simultaneous analysis of coumaphos, bromopropylate, amitraz and fluvalinate. For thymol, one clean up on a solid-phase extraction C18 (500 mg, 6 ml) column was performed; for rotenone, a liquid extraction with dichloromethane was realised. Quantitative recoveries obtained with honey were satisfactory and were superior to 80%. All acaricides are identified by reversed-phase high-performance liquid chromatography with photodiode array detection. Quantification limits obtained were below maximal residue limits when these exist.

  9. Acaricide residues in laying hens naturally infested by red mite Dermanyssus gallinae.

    Directory of Open Access Journals (Sweden)

    Marianna Marangi

    Full Text Available In the poultry industry, control of the red mite D. gallinae primarily relies worldwide on acaricides registered for use in agriculture or for livestock, and those most widely used are carbamates, followed by amidines, pyrethroids and organophosphates. Due to the repeated use of acaricides--sometimes in high concentrations--to control infestation, red mites may become resistant, and acaricides may accumulate in chicken organs and tissues, and also in eggs. To highlight some situations of misuse/abuse of chemicals and of risk to human health, we investigated laying hens, destined to the slaughterhouse, for the presence of acaricide residues in their organs and tissues. We used 45 hens from which we collected a total of 225 samples from the following tissues and organs: skin, fat, liver, muscle, hearth, and kidney. In these samples we analyzed the residual contents of carbaryl and permethrin by LC-MS/MS.Ninety-one (40.4% samples were positive to carbaryl and four samples (1.7% were positive to permethrin. Concentrations of carbaryl exceeding the detection limit (0.005 ppm were registered in the skin and fat of birds from two farms (p<0.01, although these concentrations remained below the maximum residue limit (MRLs (0.05 ppm (p<0.01. All organs/tissues of hens from a third farm were significantly more contaminated, with skin and muscle samples exceeding the MRL (0.05 ppm (p<0.01 of carbaryl in force before its use was banned. Out of 45 chickens tested, 37 (82.2% were found to be contaminated by carbaryl, and 4 (8.8% by permethrin. The present study is the first report on the presence of pesticides banned by the EU (carbaryl or not licensed for use (permethrin in the organs and tissues of laying hens, which have been treated against red mites, and then slaughtered for human consumption at the end of their life cycle.

  10. Acaricide residues in laying hens naturally infested by red mite Dermanyssus gallinae.

    Science.gov (United States)

    Marangi, Marianna; Morelli, Vincenzo; Pati, Sandra; Camarda, Antonio; Cafiero, Maria Assunta; Giangaspero, Annunziata

    2012-01-01

    In the poultry industry, control of the red mite D. gallinae primarily relies worldwide on acaricides registered for use in agriculture or for livestock, and those most widely used are carbamates, followed by amidines, pyrethroids and organophosphates. Due to the repeated use of acaricides--sometimes in high concentrations--to control infestation, red mites may become resistant, and acaricides may accumulate in chicken organs and tissues, and also in eggs. To highlight some situations of misuse/abuse of chemicals and of risk to human health, we investigated laying hens, destined to the slaughterhouse, for the presence of acaricide residues in their organs and tissues. We used 45 hens from which we collected a total of 225 samples from the following tissues and organs: skin, fat, liver, muscle, hearth, and kidney. In these samples we analyzed the residual contents of carbaryl and permethrin by LC-MS/MS.Ninety-one (40.4%) samples were positive to carbaryl and four samples (1.7%) were positive to permethrin. Concentrations of carbaryl exceeding the detection limit (0.005 ppm) were registered in the skin and fat of birds from two farms (p<0.01), although these concentrations remained below the maximum residue limit (MRLs) (0.05 ppm) (p<0.01). All organs/tissues of hens from a third farm were significantly more contaminated, with skin and muscle samples exceeding the MRL (0.05 ppm) (p<0.01) of carbaryl in force before its use was banned. Out of 45 chickens tested, 37 (82.2%) were found to be contaminated by carbaryl, and 4 (8.8%) by permethrin. The present study is the first report on the presence of pesticides banned by the EU (carbaryl) or not licensed for use (permethrin) in the organs and tissues of laying hens, which have been treated against red mites, and then slaughtered for human consumption at the end of their life cycle.

  11. Cyclic Ketoenols – Acaricides and Insecticides with a Novel Mode of Action

    Directory of Open Access Journals (Sweden)

    Dejan Marčić

    2011-01-01

    Full Text Available Modern crop protection industry puts great efforts into the investigation and development of pesticides (insecticides, acaricides with a novel mode of action, primarily because of increasingly important problem of resistance of pest organisms to pesticides.Resistance of many pest arthropod species (insects and mites to insecticides and/or acaricides became a global phenomenon in the last decades. Therefore, pest management heavily relies on constant introduction of novel active ingredients in use, i.e. onthe alternative use of a number of compounds with different modes of action in order to save the longevity of newly developed products. Among pest arthropods, according to the potential for resistance development and a number of documented cases, spider mites (Acari: Tetranychidae, especially species Tetranychus urticae and Panonychusulmi, as well as certain species of whiteflies and leaf aphids (Homoptra: Aleyrodidae,Aphididae stand out. In 2002, the company Bayer CropScience introduced spirodiclofen, a tetronic acid derivative and the first cyclic ketoenol, acaricide with a wide spectrum and a novel mode of action – inhibition of acetyl-CoA-carboxylase. Soon after, spiromesifen was introduced, also a derivative of tetronic acid, acaricide and insecticide intended for control of phytophagous mites and whiteflies. Spirotetramat, a tetramic acid derivative, and the third member of the ketoenol group, was recently commercialised as an insecticide efficient against whiteflies,leaf aphids and other harmful Homoptera. In this paper are presented the most significant properties of cyclic ketoenols, aiming at pointing to the possibilities and prospects of their use, but also to potential problems and limitations.

  12. DROSOPHILA MELANOGASTER MG. AS THE TEST-OBJECT FOR SCREENING XENOBIOTICS ON ACARICIDAL ACTIVITY

    Directory of Open Access Journals (Sweden)

    Belokon S.V.

    2015-04-01

    Full Text Available The development of new effective test systems for screening xenobiotics on biological activity, including its possible harmful influence on the organism is the modern challenge. Test systems of eukaryotic origin are needed for testing of xenobiotics on their gonadotoxical, embryotoxic, teratogenic, and carcinogenic effects. Such testing should include the monitoring of genetic effects of bioactive compounds and the possible mutagenic effect. The Drosophila melanogaster Mg. is very convenient test object as a classical genetics object, for which the genome is fully sequenced. It is convenient and easy to find out the frequency of crossingover in different parts of the genome, and study the key indicators of vitality and ontogenetic adaptation (fertility, longevity, survival under stress conditions, etc. on Drosophila. The crossover frequency, in our opinion, can be an integral factor for the general state of genotype.so we could use the mark of genetic recombination frequency as one of the indicators of the impact of xenobiotics. In this study we examined the possibility of using Drosophila melanogaster Mg. (Diptera, Drosophilidae as a test object for screening xenobiotics on acaricidal activity. Sensitivity of flies to acaricides piridaben (Sanmayt and proparhit (Omayt was studied by their fitness, longevity, fertility, and frequency of meiotic recombination in the area b-vg second chromosome. It was found that the studied compounds - piridaben and proparhit have significant influence on vitality of D. melanogaster. The presence of these acaricides in the nutrition of flies testifies the harmful influence on their crossingover and reduced fecundity and longevity. We suggested to use the D. melanogaster as a test object for screening xenobiotics on acaricidal activity.

  13. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  14. Acaricidal activity of different extracts from Syzygium cumini L. Skeels (Pomposia) against Tetranychus urticae Koch

    Institute of Scientific and Technical Information of China (English)

    Abd El-Moneim MR Afify; Hossam S El-Beltagi; Sayed A Fayed; Emad A Shalaby

    2011-01-01

    Objective: To investigate the acaricidal activity of different extracts from Syzygium cumini (S.cumini) (Pomposia) againsst Tetranychus urticae Koch (T. urticae) and the biochemical changes in antioxidants enzymes. Methods: Six extracts of S. cumini (Pomposia) at concentrations of 75, 150 and 300μg/mL were used to control T. urticae (Koch). Results: The ethanol extract showed the most efficient acaricidal activity agent against T. urticae (98.5%) followed by hexane extract (94.0%), ether and ethyl acetate extract (90.0%). The LC50 values of the promising extract were 85.0, 101.0, 102.0 and 98.0μg/mL, respectively. The activities of enzymes including ascorbate peroxidase (APX), peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) in susceptible mites were increased. The activities of all antioxidant enzymes reach the maximum value in mites at LC50 with ethanol and ethyl acetate extracts, respectively. Conclusions: The extract of S. cumini has acaricidal acivity against T. urticae, and the ethanol extract is the most efficient.

  15. Comparison of two ultrasound-enhanced microextractions combined with HPLC for determining acaricides in water.

    Science.gov (United States)

    Peng, Bing; Yang, Xiaoling; Zhang, Jiaheng; Du, Fengpei; Zhou, Wenfeng; Gao, Haixiang; Lu, Runhua

    2013-07-01

    An ultrasound-enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound-enhanced ionic-liquid-assisted dispersive liquid-liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C8MIM][PF6]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic-liquid-assisted dispersive liquid-liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.

  16. A Class of Promising Acaricidal Tetrahydroisoquinoline Derivatives: Synthesis, Biological Evaluation and Structure-Activity Relationships

    Directory of Open Access Journals (Sweden)

    Rui Yang

    2014-06-01

    Full Text Available As part of our continuing research on isoquinoline acaricidal drugs, this paper reports the preparation of a series of the 2-aryl-1-cyano-1,2,3,4-tetrahydroisoquinolines with various substituents on the N-phenyl ring, their in vitro acaricidal activities against Psoroptes cuniculi, a mange mite, and discusses their SAR as well. The structures of all compounds, including 12 new ones, were elucidated by analysis of UV, IR, NMR, ESI-MS, HR-MS spectra and X-ray diffraction experiments. All target compounds showed varying degrees of activity at 0.4 mg/mL. Compound 1 showed the strongest activity, with a 50% lethal concentration value (LC50 of 0.2421 μg/mL and 50% lethal time value (LT50 of 7.79 h, comparable to the standard drug ivermectin (LC50 = 0.2474 μg/mL; LT50 = 20.9 h. The SAR showed that the substitution pattern on the N-aromatic ring exerted a significant effect on the activity. The substituents 2'-F, 3'-F, 2'-Cl, 2'-Br and 2'-CF3 remarkably enhanced the activity. Generally, for the isomers with the same substituents at different positions, the order of the activity was ortho > meta > para. It was concluded that the target compounds represent a class of novel promising candidates or lead compounds for the development of new tetrahydroisoquinoline acaricidal agents.

  17. Toxicity of spiromesifen and natural acaricides to Tetranychus urticae koch and compatibility with Phytoseiulus macropilis (Banks

    Directory of Open Access Journals (Sweden)

    José Vargas de Oliveira

    2013-12-01

    Full Text Available The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae, is one important pest of cotton crop due to reductions in cotton yield and fiber quality. Thus, this work evaluated the toxicity of the synthetic acaricide spiromesifen and natural products on T. urticae and the compatibility with the predatory mite Phytoseiulus macropilis (Banks (Acari: Phytoseiidae. Spiromesifen and the natural products Azadirachtin A/B, Azadirachtin 1%, Jatropha curcas L. and Ricinus communis L. oils were used at different concentrations; the leaf dipping method was employed. The mortality of T. urticae females and eggs was evaluated 48 and 96 h after treatment to calculate the lethal concentrations. The effect on P. macropilis was studied using the LC50s obtained to T. urticae. All acaricides tested were effective in controlling females and eggs of T. urticae. However, according to the LC50s and LC90s calculated, spiromesifen was the most toxic acaricide to females and J. curcas oil presented the higher toxicity to eggs. Spiromesifen, J. curcas oil and Azadiractina 1% caused side effects on P. macropilis. However, only espiromesifeno was classified as harmful to the predator, whereas Azadirachtin A/B and R. communis oil were slightly harmful. R. communis and Azadirachtin A/B were effective in controlling the two-spotted spider mite and promising for the management of this pest in cotton considering their low toxicity to the predator.

  18. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  19. 75 FR 28804 - An Exposure Assessment of Polybrominated Diphenyl Ethers (PBDEs)

    Science.gov (United States)

    2010-05-24

    ... AGENCY An Exposure Assessment of Polybrominated Diphenyl Ethers (PBDEs) AGENCY: Environmental Protection...'s 2006 Polybrominated Diphenyl Ethers (PBDEs) Project Plan. This document ] provides an assessment of the exposure of Americans to polybrominated diphenyl ethers (PBDEs), a class of brominated...

  20. Isolation and identification of novel macrocyclic lactones from Streptomyces avermitilis NEAU1069 with acaricidal and nematocidal activity.

    Science.gov (United States)

    Wang, Xiang-Jing; Wang, Ming; Wang, Ji-Dong; Jiang, Ling; Wang, Ji-Jia; Xiang, Wen-Sheng

    2010-03-10

    Bioactivity-guided fractionation of Streptomyces avermitilis NEAU1069 fermentation broth was used to isolate and determine the chemical identity of bioactive constituents with acaricidal and nemotocidal activity. The structures of novel compounds 1 and 2 were determined on the basis of spectroscopic analysis, including 1D and 2D NMR as well as HRESI-MS, ESI-MS of spectrometry analysis, UV and IR spectroscopic analyses, and comparison with data from the literature. The acaricidal activities of the isolated compounds against adult mites and mite eggs were evaluated by mortality and unhatched eggs. The nematocidal activity of the isolated compounds against Caenorhabditis elegans was calculated according to the immobilized rates against the total number of tested nematodes. The results indicated that compounds 1 and 2 exhibited potent acaricidal activity against adult mites, with a mortality of >90% at a concentration of 30 microg/mL. However, compounds 1 and 2 showed only weak acaricidal activity against mite eggs, with unhatched mite egg rates of 90% at a concentration of 10 microg/mL. These results demonstrate that compounds 1 and 2, especially compound 2, have potential as pesticides with acaricidal and nematocidal activity.

  1. Dermatophagoides in childhood asthma. Allergy to dermatophagoides associates more severe childhood asthma with a potential role for acaricides.

    Science.gov (United States)

    Adham, Tamer M; Tawfik, Safwat A

    2012-03-01

    To evaluate hypersensitivity to Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae) in pediatric patients with asthma, and the use of acaricides. This is a randomized controlled trial in 82 asthmatic children. They were recruited and evaluated for severity and chronicity according to the Global Initiative for Asthma Guidelines. The study was carried out in the Pediatric Allergy Clinic, Al Noor Hospital, Khalifa Branch, Abu Dhabi, United Arab Emirates between September 2008 and June 2010. Skin prick test (SPT) was performed including D. pteronyssinus and D. farinae, and for those who were sensitive to one, or the other. The therapeutic value of acaricides was evaluated by assessing the severity of asthma before and after their use. Approximately 81.7% of asthmatics were sensitive to house dust mites (HDM). Hypersensitivity was associated with the more severe and persistent asthma (p=0.029). The manifested severity of asthma was not HDM species-specific. There was a linear association between response of children to acaricides and increasing severity of asthma. Hypersensitivity to HDM is an important factor for persistent and severe forms of asthma. Acaricides can help control childhood asthma, and we recommend SPT as part of the routine work-up of patients with asthma to determine HDM sensitive patients that can benefit from acaricides use.

  2. IN VITRO EFFICACY OF COMMERCIAL ACARICIDES INDICATE RESISTANT POPULATIONS OF RHIPICEPHALUS (BOOPHILUS MICROPLUS IN NORTHERN REGION OF MATO GROSSO

    Directory of Open Access Journals (Sweden)

    C. Eckstein

    2016-02-01

    Full Text Available Ticks are responsible for high economic and production losses on cattle production, and the use of acaricides is the main form of control applied. In recent decades, the resistance of ticks to acaricides was exacerbated by incorrect use of products, compromising the effectiveness of treatments. This study aimed to determine in vitro effectiveness of commercial acaricides in six populations of Rhipicephalus (Boophilus microplus in northern region of Mato Grosso. On average 100 engorged females were collected from each herd, which were selected and separated into homogeneous groups, sanitized, and immersed to acaricide diluted according to the manufacturer's statement, on sequence there was incubated. After the incubation was obtained from female reproductive efficiency and effectiveness of the tested acaricides. The association cypermethrin+ chlorpyrifos + citronellal showed satisfactory efficiency (> 95% in all the properties (mean 99.86% in properties, followed by trichlorfon (83.45%, amitraz (72.33%, neem oil (67.23% and cypermethrin (22.97%, which was not effective in any property. It indicates the use of the association cypermethrin +chlorpyrifos+ citronellal on evaluated properties for control of cattle tick effectively.

  3. Differential genotoxicity of diphenyl diselenide (PhSe2 and diphenyl ditelluride (PhTe2

    Directory of Open Access Journals (Sweden)

    Daiane Francine Meinerz

    2014-03-01

    Full Text Available Organoselenium compounds have been pointed out as therapeutic agents. In contrast, the potential therapeutic aspects of tellurides have not yet been demonstrated. The present study evaluated the comparative toxicological effects of diphenyl diselenide (PhSe2 and diphenyl ditelluride (PhTe2 in mice after in vivo administration. Genotoxicity (as determined by comet assay and mutagenicicity were used as end-points of toxicity. Subcutaneous administration of high doses of (PhSe2 or (PhTe2 (500 µmol/kg caused distinct genotoxicity in mice. (PhSe2 significantly decreased the DNA damage index after 48 and 96 h of its injection (p < 0.05. In contrast, (PhTe caused a significant increase in DNA damage (p < 0.05 after 48 and 96 h of intoxication. (PhSe2 did not cause mutagenicity but (PhTe2 increased the micronuclei frequency, indicating its mutagenic potential. The present study demonstrated that acute in vivo exposure to ditelluride caused genotoxicity in mice, which may be associated with pro-oxidant effects of diphenyl ditelluride. In addition, the use of this compound and possibly other related tellurides must be carefully controlled.

  4. Acaricidal activity of Melaleuca alternifolia (tea tree) oil: in vitro sensitivity of sarcoptes scabiei var hominis to terpinen-4-ol.

    Science.gov (United States)

    Walton, Shelley F; McKinnon, Melita; Pizzutto, Susan; Dougall, Annette; Williams, Edwina; Currie, Bart J

    2004-05-01

    To compare the acaricidal activity of Melaleuca alternifolia (tea tree) oil (TTO) and some of its individual active components on the itch mite Sarcoptes scabiei var hominis. In vitro acaricide sensitivity assessment. The Menzies School of Health Research laboratory, located near the Infectious Diseases Ward of the Royal Darwin Hospital, Australia, where patients are admitted and treated for crusted scabies. Scabies mites (S scabiei var hominis) were collected from a 20-year-old Aboriginal woman admitted to the Royal Darwin Hospital with crusted scabies. Interventions Within 3 hours of collection, scabies mites were placed in continuous direct contact with the TTO products and control acaricides and were observed at regular intervals. Percentage of mites dead at regular observation intervals between 5 minutes and 24 hours during continuous exposure to the TTO products and acaricides. The 5% TTO and active component terpinen-4-ol were highly effective in reducing mite survival times. Statistically significant differences in mite survival curves were observed for 5% TTO, 2.1% terpinen-4-ol, 5% permethrin, and ivermectin (100 microg/g of Emulsifying Ointment British Pharmacopoeia 88). In vivo effectiveness was also observed. Documentation of resistance against antiectoparasitic compounds is increasing. Reported S scabiei treatment failures with lindane, crotamiton, and benzyl benzoate, as well as likely emerging resistance to 5% permethrin and oral ivermectin, are of concern and advocate for the identification and development of novel acaricidal drugs. Tea tree oil is a membrane-active biocide extracted from the tree M alternifolia. It is a principal antimicrobial in a wide range of pharmaceuticals sold in Australia, with the main active component being oxygenated terpenoids. The results suggest that TTO has a potential role as a new topical acaricide and confirm terpinen-4-ol as the primary active component.

  5. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  6. Resistance status of ticks (Acari; Ixodidae) to amitraz and cypermethrin acaricides in Isoka District, Zambia.

    Science.gov (United States)

    Muyobela, Jackson; Nkunika, Philip Obed Yobe; Mwase, Enala Tembo

    2015-12-01

    This study was designed to obtain data on the farmer's approach to tick control and to determine whether Rhipicephalus appendiculatus Neuman, Amblyomma variegatum (Fabricius), and Rhipicephalus (Boophilus) microplus (Canestrini) were resistant to amitraz and cypermethrin acaricides, in Isoka District, Zambia. Prevailing tick control practices were documented by administering a semi-structured questionnaire to 80 randomly selected smallholder livestock farmers from four agricultural camps (Longwe, Kantenshya, Kapililonga, and Ndeke) in Isoka District. Modified larval packet test (LPT) bioassay experiments were used to determine the resistance status of the common tick species against amitraz and cypermethrin acaricides. Fifty percent of respondents practiced chemical tick control with amitraz (27 %) and cypermethrin (23 %) being the acaricides in use, and were applied with knapsack sprayers. Less than 3 l of spray wash per animal was used which was considerably lower than the recommended delivery rate of 10 l of spray wash per animal. No significant susceptibility change to amitraz at 95 % confidence level was observed in R. appendiculatus and A. variegatum against amitraz. However, a significant change in the susceptibility of R. (Bo.) microplus tested with amitraz was detected at 95 % confidence. The test population had a lower susceptibility (LD50 0.014 %; LD90 0.023 %) than the reference population (LD50 0.013 %; LD90 0.020 %). The results indicated that resistance to amitraz was developing in R. (Bo.) microplus. For cypermethrin, no significant susceptibility change at 95 % confidence was observed in any of the three species and thus resistance to this chemical was not observed.

  7. Acaricidal activity of Swietenia mahogani and Swietenia macrophylla ethanolic extracts against Varroa destructor in honeybee colonies.

    Science.gov (United States)

    El Zalabani, Soheir M; El-Askary, Hesham I; Mousa, Ola M; Issa, Marwa Y; Zaitoun, Ahmed A; Abdel-Sattar, Essam

    2012-02-01

    The acaricidal (miticidal) activity of 90% ethanolic extracts of leaves and stem bark of Swietenia mahogani and Swietenia macrophylla were tested against Varroa destructor mite. Four concentrations were used over two different time intervals under laboratory and field conditions. In general, it was noticed that the acaricidal effect based on mortality and LC(50) of all tested extracts against the Varroa mite was concentration and time dependant. The acaricidal action against Varroa mites was relatively the least for the S. macrophylla stem bark extract at 500 ppm concentration after 48 h while it reached 100% and 95% in case of S. mahogani bark and S. macrophylla leaves, respectively. The% infestation with Varroa in colonies treated with the different extracts at various time intervals showed that the rate of infestation decreased to 0.0% after 12 days from the beginning of treatments with 500 ppm of S. mahogani leaves extract compared to 0.79% decrease after treatment with Mitac, a reference drug (60 mg/colony). The rate of infestation in case of treatments with S. mahogani bark, S. macrophylla leaves and S. macrophylla bark was decreased to 0.11%, 2.41% and 1.08%, respectively. The highest reduction was observed with S. mahogani leaves extract followed by S. mahogani bark. All the tested extracts showed less or no effect on honey bees at the different concentrations and at different bioassay times. This study suggested that the use of natural plant extracts or their products as ecofriendly biodegradable agents could be of high value for the control of Varroa mite.

  8. Studies on Acaricidal Bioactivities of Artemisia annua L. Extracts Against Tetranychus cinnabarinus Bois. (Acari: Tetranychidae)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-qiang; DING Wei; ZHAO Zhi-mo; WU Jing; FAN Yu-hu

    2008-01-01

    The aim of this study was to determine the best extraction technique, the most suitable solvent, the optimal plant parts,and the acaricidal activities of Artemisia annua L. The petroleum ether (30-60℃), petroleum ether (60-90℃), ethanol,acetone, and water parallel and sequenced extracts were obtained from the leaves, stems and roots of different period of A. annua L. in April, May, June, July and September respectively. And then the acaricidal bioactivities against Tetranychus cinnabarinus of all extracts were determined by the slide-capillary method in the laboratory. The results indicated that the acaricidal bioactivities elevated as the development of A. annua plant at the concentration of 5 mg mL-1. The general tendency exhibited the sequence of July > June > May > April, but September decreased comparing to July. However, the most effective extracts in five months were all acetone parallel extract of A. annua leaf, and the corrected mortalities treated after 48 h ranged from 74 to 100%. The median lethal concentrations (LC50) against T. cinnabarinus of acetone parallel extracts of A. annua leaves in September, July, June, May and April were 0.5986, 0.4341, 0.8376, 0.9443 and 1.3817 mg mL-1, respectively, treated after 48 h. The 13 groups were isolated from acetone extracts of A. annua leaves in July by column chromatography, both the 11th and 12th groups exhibited strong bioactivities. The median lethal concentrations of the 11th and 12th groups against T. cinnabarinus were 0.3683 and 0.1586 mg mL-1, respectively. The acetone parallel extract of A. annua leaf in July was the most toxic to T. cinnabarinus and the corrected mortality was 100% after 48 h. The acetone parallel extract of the 11th and 12th groupswere the most active components, acted as the emphases in further study.

  9. Acaricidal activity of aqueous extracts of camomile flowers, Matricaria chamomilla, against the mite Psoroptes cuniculi.

    Science.gov (United States)

    Macchioni, F; Perrucci, S; Cecchi, F; Cioni, P L; Morelli, I; Pampiglione, S

    2004-06-01

    Arcaricidal properties of decoctions, infusions and macerates of dried flower heads of camomile, Matricaria chamomilla L. (Asterales: Asteraceae) were tested in vitro against the mite Psoroptes cuniculi Delafond (Parasitiformes: Psoroptidae). This mite species is responsible for otoacariasis in domestic animals. Mites were exposed to the extracts for 24, 48 or 72 h. All the extracts tested showed highly significant acaricidal activity when compared with controls. Among them, a decoction of 10% was the only formulation which gave 100% activity at all the three observations times.

  10. Acaricidal effect of Cassia fistula Linn. leaf ethanolic extract against Rhipicephlaus (Boophilus) annulatus.

    Science.gov (United States)

    Sunil, A R; Amithamol, K K; Juliet, S; Nair, S N; Ajithkumar, K G; Soorya, V C; Divya, T M; Jyothymol, G; Ghosh, S; Ravindran, R

    2013-06-01

    The present study evaluates the acaricidal properties of crude ethanolic extract of Cassia fistula leaves for controlling Rhipicephalus (Boophilus) annulatus based on adult immersion test (AIT). The percentage of adult mortality, inhibition of fecundity and hatching of ova laid were studied at different concentrations of the extract ranging from 50 to 100 mg / ml. The results were compared using one-way ANOVA. The extract produced complete inhibition of hatching of eggs at concentrations above 80 mg / ml of the extract. Mortality of adult engorged female ticks and inhibition of fecundity were concentration dependent. The LC50 value of extract against R. (B.) annulatus was 97.1 mg / ml.

  11. Demodex folliculorum and topical treatment: acaricidal action evaluated by standardized skin surface biopsy.

    Science.gov (United States)

    Forton, F; Seys, B; Marchal, J L; Song, A M

    1998-03-01

    A standardized skin surface biopsy was performed in 34 patients suffering from skin diseases with high Demodex folliculorum density (Dd) > 5D/cm2 before, during and after topical treatment. The patients were randomized into six comparable groups to study six topical treatments: metronidazole 2%, permethrin 1%, sublimed sulphur 10%, lindane 1%, crotamiton 10% and benzyl benzoate (BB) 10%. Their acaricidal activity was measured according to three criteria: (i) for each treatment, decrease of Dd to under the normal threshold (crotamiton was demonstrated by the second criterion. An important irritating effect was observed with BB and sulphur.

  12. Essential oils and Beauveria bassiana against Dermanyssus gallinae (Acari: Dermanyssidae): Towards new natural acaricides.

    Science.gov (United States)

    Immediato, Davide; Figueredo, Luciana Aguiar; Iatta, Roberta; Camarda, Antonio; de Luna, Rafaela Lira Nogueira; Giangaspero, Annunziata; Brandão-Filho, Sinval Pinto; Otranto, Domenico; Cafarchia, Claudia

    2016-10-15

    Essential oils (EOs) and entomopathogenic fungi such as Beauveria bassiana (Bb) strains have the potential to be used as alternative insecticides and acaricides for controlling ectoparasites as Dermanyssus gallinae. These compounds have some limitations in their use: the acaricidal effect of EOs is rapid, but short-lived, whilst that of Bb is delayed, but long-lived. To evaluate the effect of both compounds combined against D. gallinae, the non-toxic dose of Eucalyptus globulus, Eucalyptus citriodora, Thymus vulgaris and Eugenia caryophyllata essential oils were firstly calculated for "native" strains of Bb. Subsequently, the effects of the combination of selected EOs with Bb against nymph and adult poultry red mites (PRMs) was assessed. EO concentrations ranging from 0.0015 to 8% v/v (i.e., nine double dilutions) were used to evaluate their effect on germination, sporulation and vegetative growth rates of native strains of Bb. A total of 1440 mites (720 nymphs and 720 adults) were divided into three-treated group (TGs) and one control group (CG). In TGs, mites were exposed to Bb in combination with the selected EO (TG1), EO alone (TG2) or Bb (TG3) alone. In the CG, mites were exposed to 0.1% tween 80 plus EO solvent (CG). E. globulus and E. citriodora were toxic for Bb in concentrations higher than 0.2% and 0.003% respectively, whilst E. caryophyllata and T. vulgaris were toxic at all concentrations tested against Bb. Based on the results of the toxicity assays against Bb, E. globulus was chosen to be tested as acaricide resulting non-toxic for Bb at concentration lower than 0.4%. Increased mortality of D. gallinae adults was recorded in TG1 than those in other TGs from 4days post-infection (T+4DPI). A 100% mortality of D. gallinae was recorded in adults at T+9DPI and at T+10DPI in nymphs in TG1 and later than T+11DPI in the other TGs. Used in combination with E. globulus, Bb displayed an earlier acaricidal effect towards both haematophagous D. gallinae stages

  13. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  14. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

    Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

  15. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  16. Spatial trends of polybrominated diphenyl ether (PBDE) congeners

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Spatial trends of polybrominated diphenyl ether (PBDE) congeners were analyzed in young of the year bluefish collected along the U.S. Atlantic coastline from...

  17. 4,5-Diphenyl-1-methylimidazole: An Undergraduate Laboratory Experiment.

    Science.gov (United States)

    Anastas, Paul T.; And Others

    1985-01-01

    Background information and procedures used are provided for the synthesis of 4,5-diphenyl-methylimidazole. This experiment on the chemistry of heterocycles is ideally suited for beginning undergraduate organic chemistry students. (JN)

  18. Acaricidal properties of the formulations based on essential oils from Cymbopogon winterianus and Syzygium aromaticum plants.

    Science.gov (United States)

    de Mello, Valéria; Prata, Márcia Cristina de Azevedo; da Silva, Márcio Roberto; Daemon, Erik; da Silva, Luciane Santos; Guimarães, Flávia del Gaudio; de Mendonça, Alessandra Esther; Folly, Evelize; Vilela, Fernanda Maria Pinto; do Amaral, Lilian Henriques; Cabral, Lucio Mendes; do Amaral, Maria da Penha Henriques

    2014-12-01

    The cattle tick, Rhipicephalus (Boophilus) microplus, has caused serious harm to livestock raising in Brazil, considering the costs of controlling it, loss of revenue due to smaller production of milk and meat, and damage to leather, in addition to transmitting diseases. The use of medicinal plants is considered an alternative to the recurring resistance to chemicals. Due to the need for efficient alternatives with less environmental impact, this study aimed to develop contact formulations with essential oils from the Java citronella (Cymbopogon winterianus) and clove (Syzygium aromaticum) plants and to assess in vitro the effects in different stages of the tick cycle. In the present study, concentrations from 0.5-15.0% of the essential oils incorporated in the formulations were used. The ticks from different geographical areas were treated with those formulations, and their effects on the production levels of eggs, on the larvae hatching, and their efficiency on ticks were assessed. The obtained results were compared with other commercial acaricidal products. After the 20th day of treatment, the formulations with citronella essential oil had 2.09-55.51% efficiency, depending on the concentration of the oil incorporated. The efficiency of the treatment with formulations containing clove essential oil was higher, from 92.47-100%. The results showed the acaricidal effects of the formulations tested when compared to commercial chemical products. In vivo studies should be performed in order to assess the efficiency of those formulations in the fields, aiming to use these products as an alternative for controlling cattle ticks.

  19. A 10 year survey of acaricide residues in beeswax analysed in Italy.

    Science.gov (United States)

    Boi, Michela; Serra, Giorgia; Colombo, Roberto; Lodesani, Marco; Massi, Sergio; Costa, Cecilia

    2016-07-01

    The aim of this work was to provide an overview of the prevalence and level of acaricides in beeswax used in Italy in the past 10 years by analysing 1319 beeswax samples processed by the certified laboratory of the Italian Bee Research Institute. The proportion of samples positive to at least one active ingredient decreased between 2005 and 2009 (from 69 to 32%) and then increased again between 2009 and 2014 (from 32 to 91%). This trend is in agreement with reports from beekeepers that the use of synthetic acaricides decreased in the second half of the past decade and increased after the beginning of the colony losses phenomenon. The active ingredient with the greatest overall proportion of positive samples was coumaphos (49%), followed by fluvalinate (38%) and chlorphenvinphos (25%). The indicator for amitraz, 2,4-dimethylphenylformamide (DMPF), was detected in a very small proportion of samples (6%), while residues of cymiazole were never found. In more than half of the analysed samples, residues of at least one active ingredient were detected. The mean levels of residues of all the considered active ingredients in the positive samples may represent a source of accumulation in beeswax and pose risks to honey bee health. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  20. Direct effect of acaricides on pathogen loads and gene expression levels in honey bees Apis mellifera.

    Science.gov (United States)

    Boncristiani, Humberto; Underwood, Robyn; Schwarz, Ryan; Evans, Jay D; Pettis, Jeffery; vanEngelsdorp, Dennis

    2012-05-01

    The effect of using acaricides to control varroa mites has long been a concern to the beekeeping industry due to unintended negative impacts on honey bee health. Irregular ontogenesis, suppression of immune defenses, and impairment of normal behavior have been linked to pesticide use. External stressors, including parasites and the pathogens they vector, can confound studies on the effects of pesticides on the metabolism of honey bees. This is the case of Varroa destructor, a mite that negatively affects honey bee health on many levels, from direct parasitism, which diminishes honey bee productivity, to vectoring and/or activating other pathogens, including many viruses. Here we present a gene expression profile comprising genes acting on diverse metabolic levels (detoxification, immunity, and development) in a honey bee population that lacks the influence of varroa mites. We present data for hives treated with five different acaricides; Apiguard (thymol), Apistan (tau-fluvalinate), Checkmite (coumaphos), Miteaway (formic acid) and ApiVar (amitraz). The results indicate that thymol, coumaphos and formic acid are able to alter some metabolic responses. These include detoxification gene expression pathways, components of the immune system responsible for cellular response and the c-Jun amino-terminal kinase (JNK) pathway, and developmental genes. These could potentially interfere with the health of individual honey bees and entire colonies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Acaricidal activity of constituents identified in Foeniculum vulgare fruit oil against Dermatophagoides spp. (Acari: Pyroglyphidae).

    Science.gov (United States)

    Lee, Hoi-Seon

    2004-05-19

    Acaricidal activities of components derived from Foeniculum vulgare fruit oil against Dermatophagoides farinae and Dermatophagoides pteronyssinus were examined using direct contact application and compared with that of the commercial repellent benzyl benzoate. The major biologically active constituent of Foeniculum fruit oil was characterized as (+)-fenchone by spectroscopic analyses. On the basis of LD(50) values, the compound most toxic to D. farinae was p-anisaldehyde (11.3 mg/m(2)) followed by (+)-fenchone (38.9 mg/m(2)), (-)-fenchone (41.8 mg/m(2)), benzyl benzoate (89.2 mg/m(2)), thymol (90.3 mg/m(2)), and estragol (413.3 mg/m(2)). Against D. pteronyssinus, p-anisaldehyde (10.1 mg/m(2)) was much more effective than benzyl benzoate (67.5 mg/m(2)), thymol (68.5 mg/m(2)), and estragol (389.9 mg/m(2)). These results indicate that the acaricidal activity of F. vulgare fruit oil likely results from (+)-fenchone and p-anisaldehyde. (+)-Fenchone was 20.3 times more abundant in the oil than p-anisaldehyde. (+)-Fenchone and p-anisaldehyde merit further study as potential house dust mite control agents or as lead compounds.

  2. Body size variability of Varroa destructor and its role in acaricide tolerance.

    Science.gov (United States)

    Maggi, Matías; Peralta, Luciano; Ruffinengo, Sergio; Fuselli, S; Eguaras, Martín

    2012-06-01

    Phenotypic plasticity has been defined as the ability of a genotype to produce different phenotypes when exposed to distinct environments throughout its ontogeny. Morphological variability of individuals is an example of this plasticity. Taking into account that several studies have reported a wide morphological variability in Varroa destructor populations, we evaluated if the body size plasticity of the parasite constituted a key factor able to modulate mites survival when they were exposed to a drug bioassays. Drug bioassays against mites were conducted using three different Syzygium aromaticum essential oil concentrations (0.5, 1, and 5 μl/capsule) and controls. After 4 h of exposition, mite mortality was registered. The width (WS) and length (LS) of the dorsal shield were measured in dead mites. General lineal models were carried to determine if V. destructor survival to acaricides was related to the explanatory variables. Data modelling confirmed that WS and LS variables, together with time interaction, were significantly related to V. destructor survival when the parasites were exposed to acaricides. The models proposed demonstrated that for the smaller S. aromaticum essential oil concentration, the larger the parasite body, the greater the probability that it remains alive at the end of the bioassay. Such relationship was inverse for the other two concentrations tested. Possible causes explaining the body size variability in V. destructor individuals were discussed.

  3. Marine Sponge Dysidea herbacea revisited: Another Brominated Diphenyl Ether

    Directory of Open Access Journals (Sweden)

    Bruce F. Bowden

    2005-03-01

    Full Text Available Abstract: A pentabrominated phenolic diphenyl ether (1 that has not previously been reported from marine sources has been isolated from Dysidea herbacea collected at Pelorus Island, Great Barrier Reef, Australia. The structure was determined by comparison of NMR data with those of known structurally-related metabolites. NMR spectral assignments for (1 are discussed in context with those of three previously reported isomeric pentabrominated phenolic diphenyl ethers.

  4. Reduced efficacy of commercial acaricides against populations of resistant cattle tick Rhipicephalus microplus from two municipalities of Antioquia, Colombia

    Science.gov (United States)

    Two distant Antioquian cattle farms where systemic and topical acaricides had previously failed to control infestations by Rhipicephalus (Boophilus) microplus were studied. An initial in vivo study was conducted using single subcutaneous injections with a long-acting formulation of ivermectin (630 µ...

  5. Acaricidal activity of Asarum heterotropoides root-derived compounds and hydrodistillate constitutes toward Dermanyssus gallinae (Mesostigmata: Dermanyssidae).

    Science.gov (United States)

    Kim, Jun-Ran; Perumalsamy, Haribalan; Lee, Ju-Hee; Ahn, Young-Joon; Lee, Young Su; Lee, Sang-Guie

    2016-04-01

    The acaricidal activity of Asarum heterotropoides root-derived principles, methyleugenol, safrole, 3-carene, α-asarone, pentadecane and A. heterotropoides root steam distillate constituents was tested against poultry red mites Dermanyssus gallinae (De Geer). All active principles were identified by spectroscopic analysis. Results were compared with those of two conventional acaricides, benzyl benzoate and N,N-diethyl-3-methylbenzamide (DEET). Methyleugenol (24 h LC50 = 0.57 µg/cm(2)) and safrole (24 h LC50 = 8.54 µg/cm(2)) were the most toxic compounds toward D. gallinae, followed by 3,4,5-trimethoxytoluene, 3,5-dimethoxytoluene, estragole, α-terpineol, verbenone, eucarvone, linalool, and terpinen-4-ol (LC50 = 15.65-27.88 µg/cm(2)). Methyleugenol was 16.7× and 11.0× more toxic than benzyl benzoate (LC50 = 9.52 μg/cm(2)) and DEET (LC50 = 6.28 μg/cm(2)), respectively; safrole was 1.1× and 0.73× more toxic. Asarum heterotropoides root-derived materials, particularly methyleugenol and safrole, merit further study as potential acaricides. Global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments justify further studies on A. heterotropoides root extract and steam distillate preparations containing the active constituents described as potential contact-action fumigants for the control of mites.

  6. Determination of acaricide residues in saudi arabian honey and beeswax using solid phase extraction and gas chromatography.

    Science.gov (United States)

    Kamel, Alaa; Al-Ghamdi, Ahmad

    2006-01-01

    Determination of acaricide residues of flumethrin, tau-fluvalinate, coumaphos, and amitraz in honey and beeswax was carried out using a rapid extraction method utilizing C-18 SPE cartridges and an analytical method utilizing GC with ECD, NPD, and MSD detectors for the four acaricides. Recovery percentages from the extraction method ranged from 90-102%, while the minimum detection levels ranged from 0.01-0.05 mg/kg for the acaricides. Nine of the 21 analyzed samples were found to be contaminated with the acaricides tau-fluvalinate and coumaphos. Neither flumethrin nor amitraz was detected in any of the honey or wax samples. Coumaphos was found only in honey samples in which two samples exceeded the tolerance levels set by EPA and EC regulations. It has not been detected in beeswax. Five honey samples and eight beeswax samples were found to be contaminated with tau-fluvalinate. One of the wax samples was contaminated with a relatively high residue of tau-fluvalinate and contained above 10 mg/kg.

  7. Further studies on South African plants: Acaricidal activity of organic plant extracts against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

    CSIR Research Space (South Africa)

    Wellington, Kevin W

    2017-01-01

    Full Text Available The goal of our research is to develop a lower cost eco-friendly tick control method because acaricides that are commonly used to control ticks are often toxic, harmful to the environment or too expensive for resource-limited farmers. Acetone...

  8. Characterization, mode of action, and efficacy of twelve silica-based acaricides against poultry red mite (Dermanyssus gallinae) in vitro.

    Science.gov (United States)

    Schulz, Johanna; Berk, Jutta; Suhl, Johanna; Schrader, Lars; Kaufhold, Stefan; Mewis, Inga; Hafez, Hafez Mohammed; Ulrichs, Christian

    2014-09-01

    Poultry red mite infestation still is an unsolved problem in poultry farms. Legal regulations, residue risks, and resistances limit chemical control of mites. Alternatives to chemical acaricides for control of poultry red mite are silica-based products, which have as a main constituent silicon dioxide. The acaricidal effect is attributed to sorptive properties of the particles, which result in the mite's death by desiccation. In the present study, the acaricidal efficacy of 12 products containing natural or synthetic silica, 9 in powder form, and 3 for liquid application was tested under laboratory conditions. Mite mortality was measured at several intervals and the mean lethal time (LT₅₀) determined by Probit analysis after Abbott's correction. The LT₅₀ values of the products significantly differed (Tukey's HSD p < 0.05). LT₅₀ values of powdery formulations ranged from 5.1 to 18.7 h and overlapped with those of the fluid ones which ranged from 5.5 to 12.7 h. In order to explain the differences in efficacy of the tested silica products, further characterizations were carried out. X-ray fluorescence, specific surface, cation exchange capacity (CEC), and water absorption capacity (WAC) were measured. Furthermore, electron microscopy was conducted and different products compared. Silicon dioxide content (ranging from 65 to 89% for powders and 57 to 80% for fluids) had no significant impact on efficacy, while specific surface and CEC (2.4-23.2 mEq 100(-1) g(-1) for powders and 18-30.8 mEq 100(-1) g(-1)) were positively and WAC (1.3-4.4 wt% for powders and 3.3-4.8 wt% for fluids) negatively related to the acaricidal efficacy. Influence of these parameters on acaricidal efficacy was significant according to the results of a stepwise regression analysis (p < 0.01).

  9. Acaricidal properties of an Ailanthus altissima bark extract against Psoroptes cuniculi and Sarcoptes scabiei var. cuniculi in vitro.

    Science.gov (United States)

    Gu, Xiaobin; Fang, Chunlin; Yang, Guangyou; Xie, Yue; Nong, Xiang; Zhu, Junyang; Wang, Shuxian; Peng, Xuerong; Yan, Qigui

    2014-02-01

    The potential acaricidal properties of an Ailanthus altissima bark extract were assessed against two common species of animal ectoparasitic mites, Psoroptes cuniculi and Sarcoptes scabiei var. cuniculi, in vitro. A. altissima bark extract was obtained by ethanol thermal circumfluence and tested at four concentrations (1.0, 0.5, 0.25 and 0.125 g/ml) on mites collected from rabbits. Compared to the fenvalerate treatment group, the A. altissima bark exhibited significant acaricidal properties for both mite species treated. The extract of concentrations of 1.0, 0.5 and 0.25 g/ml killed all tested S. scabiei within 7 h, however, only 1.0 and 0.5 g/ml of extract killed all treated P. cuniculi. The median lethal time (LT50) values at 1, 0.5 and 0.25 g/ml were 0.60, 0.78, 1.48 h for S. scabiei and 0.74, 1.29, 3.33 h for P. cuniculi. The median lethal concentration (LC50) for P. cuniculi was approximately 1.6 times that for S. scabiei var. cuniculi at 4 h. The extract showed stronger toxicity against S. scabiei than against P. cuniculi. Mortality rates increased with increasing concentration of extract administered and with increasing time post-treatment, indicating that the acaricidal activity of A. altissima bark extract is both time-dependent and dose-dependent. This is the first report on acaricidal activity of A. altissima against P. cuniculi and S. scabiei var. cuniculi. It indicates that A. altissima contain potential acaricidal compounds. Our study is the first step to develop potentially novel compounds from A. altissima for the effective control of mites in livestock.

  10. First report of fluazuron resistance in Rhipicephalus microplus: a field tick population resistant to six classes of acaricides.

    Science.gov (United States)

    Reck, José; Klafke, Guilherme Marcondes; Webster, Anelise; Dall'Agnol, Bruno; Scheffer, Ramon; Souza, Ugo Araújo; Corassini, Vivian Bamberg; Vargas, Rafael; dos Santos, Julsan Silveira; Martins, João Ricardo de Souza

    2014-03-17

    The control of the cattle tick Rhipicephalus microplus is based mainly on the use of chemical acaricides, which has contributed to the emerging problem of selection of resistant tick populations. Currently, there are six main classes of acaricides commercially available in Brazil to control cattle ticks, with fluazuron, a tick growth regulator with acaricidal properties, being the only active ingredient with no previous reports of resistance. Ticks (designated the Jaguar strain) were collected in a beef cattle ranch located at Rio Grande do Sul state, Southern Brazil, after a complaint of fluazuron treatment failure. To characterise the resistance of this strain against acaricides, larval tests were performed and showed that the Jaguar strain was resistant to all of the drugs tested: cypermethrin (resistance ratio, RR=31.242), chlorpyriphos (RR=103.926), fipronil (RR=4.441), amitraz (RR=11.907) and ivermectin (3.081). A field trial was conducted to evaluate the efficacy of fluazuron treatment in heifers that had been experimentally infested with the Jaguar or a susceptible strain. Between 14 and 28 days after treatment, the average efficacy in cattle experimentally infested with the susceptible strain was 96%, while for the Jaguar strain the efficacy was zero. Additionally, the Jaguar strain response to fluazuron was evaluated in vitro using a modified adult immersion test (AIT) and the artificial feeding assay (AFA). With the AIT, 50 ppm of fluazuron inhibited 99% of larvae hatching in the susceptible strain (POA) and less than 50% in the Jaguar strain. Results of the AFA showed a larval hatching rate of 67% at 2.5 ppm of fluazuron with the Jaguar strain; conversely, only 3% of larvae of the susceptible strain hatched at the same fluazuron concentration. The results showed here demonstrated the first case of fluazuron resistance in R. microplus and the first tick population resistant to six classes of acaricides in Brazil.

  11. Tick repellents and acaricides of botanical origin: a green roadmap to control tick-borne diseases?

    Science.gov (United States)

    Benelli, Giovanni; Pavela, Roman; Canale, Angelo; Mehlhorn, Heinz

    2016-07-01

    Arthropods are dangerous vectors of agents of deadly diseases, which may hit as epidemics or pandemics in the increasing world population of humans and animals. Among them, ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide. Thus, the effective and eco-friendly control of tick vectors in a constantly changing environment is a crucial challenge. A number of novel routes have been attempted to prevent and control tick-borne diseases, including the development of (i) vaccines against viruses vectored by ticks; (ii) pheromone-based control tools, with special reference to the "lure and kill" techniques; (iii) biological control programmes relying on ticks' natural enemies and pathogens; and (iv) the integrated pest management practices aimed at reducing tick interactions with livestock. However, the extensive employment of acaricides and tick repellents still remains the two most effective and ready-to-use strategies. Unfortunately, the first one is limited by the rapid development of resistance in ticks, as well as by serious environmental concerns. On the other hand, the exploitation of plants as sources of effective tick repellents is often promising. Here, we reviewed current knowledge concerning the effectiveness of plant extracts as acaricides or repellents against tick vectors of public health importance, with special reference to Ixodes ricinus, Ixodes persulcatus, Amblyomma cajennense, Haemaphysalis bispinosa, Haemaphysalis longicornis, Hyalomma anatolicum, Hyalomma marginatum rufipes, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus pulchellus, Rhipicephalus sanguineus and Rhipicephalus turanicus. Eighty-three plant species from 35 botanical families were selected. The most frequent botanical families exploited as sources of acaricides and repellents against ticks were Asteraceae (15 % of the selected studies), Fabaceae (9 %), Lamiaceae (10 %), Meliaceae (5 %), Solanaceae (6

  12. Sperm viability and gene expression in honey bee queens (Apis mellifera) following exposure to the neonicotinoid insecticide Imidacloprid and the organophosphate Acaricide Coumaphos

    Science.gov (United States)

    Honey bee population declines are a global concern. Numerous factors appear to cause the decline including parasites, pathogens, malnutrition and pesticides. Residues of the organophosphate acaricide coumaphos and the neonicotinoid insecticide imidacloprid, widely used to combat Varroa mites and for...

  13. Prevalence of Resistant Strains of Rhipicephalus microplus to Acaricides in Cattle Ranch in the Tropical Region of Tecpan of Galeana, Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    J. Olivares-Pérez*, S. Rojas-Hernández, M.T. Valencia-Almazan, I. Gutiérrez-Segura and E.J. Míreles-Martínez

    2011-10-01

    Full Text Available Tick and tick borne diseases cause many problems to the cattle industry worldwide. The prevalence of resistant strains of Rhipicephalus microplus to different acaricides on cattle farms in the tropical region of Tecpan of Galeana, Guerrero, Mexico, and risk factors related to prevalence of resistant strains of R. microplus. Sixty one ranches infested were sampled; in each ranch were collected 30-50 fully-engorged female R. microplus ticks, of 10 cattle randomly selected, and evaluated in their progeny resistance to acaricides, using the larval packet test. The prevalence of resistant strains was total pyrethroids and amitraz. In organophosphorus 31.1, 48.3 and 82.2% of strains were resistant to clorpyriphos, coumaphos and diazinon, respectively. Risk factors favored (P<0.05 the development of resistant strains of acaricides. We concluded that the resistance of R. microplus to acaricides used to control a problem, and risk factors (livestock management have accelerated the development of resistance.

  14. Four new doramectin congeners with acaricidal and insecticidal activity from Streptomyces avermitilis NEAU1069.

    Science.gov (United States)

    Wang, Xiang-Jing; Zhang, Ji; Wang, Ji-Dong; Huang, Sheng-Xiong; Chen, Yi-Hua; Liu, Chong-Xi; Xiang, Wen-Sheng

    2011-11-01

    Four new doramectin congeners, 1-4, were isolated from Streptomyces avermitilis NEAU1069. The structures of 1-4 were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR as well as HR-ESI-MS, ESI-MS, UV, and IR, and comparison with literature data. All compounds exhibited noticeable acaricidal and insecticidal activities. Especially compound 2 was found to be the most potent pesticide of the compounds evaluated with the IC(50) values of 10.2, 65.1 and 124.4 μg/ml against adult two-spotted spider mites (Tetranychus urticae Koch), two-spotted spider mite eggs, and Mythimna separata, respectively, which are comparable to those of commercial pesticide milbemycin A(3)/A(4) as positive reference.

  15. Acaricidal properties of the essential oil from Zanthoxylum caribaeum against Rhipicephalus microplus.

    Science.gov (United States)

    Nogueira, Jeane; Vinturelle, Rafaelle; Mattos, Camila; Tietbohl, Luis Armando Candido; Santos, Marcelo Guerra; Junior, Itabajara Silva Vaz; Mourão, Samanta Cardozo; Rocha, Leandro; Folly, Evelize

    2014-09-01

    Zanthoxylum caribaeum Lamarck (Rutaceae) is plant species with a variety of medical applications, including insecticidal activity. This study determined the bioacaricidal activity of the essential oil from Z. caribaeum leaves against engorged Rhipicephalus (Boophilus) microplus (Canestrini, 1887) females using the adult immersion test. For this purpose, three serial concentrations (5.0, 2.5, and 1.25%, vol:vol, in 1% dimetilsulfoxide) of the essential oil were used. Essential oil 5% caused 65% mortality on the first day after treatment, 85% on the second day, and 100% mortality by the fifth day. To our knowledge, this is the first demonstration of the acaricidal activity of the essential oil from Z. caribaeum leaves against cattle ticks.

  16. Variation in chemical composition and acaricidal activity against Dermanyssus gallinae of four eucalyptus essential oils.

    Science.gov (United States)

    George, David R; Masic, Dino; Sparagano, Olivier A E; Guy, Jonathan H

    2009-06-01

    The results of this study suggest that certain eucalyptus essential oils may be of use as an alternative to synthetic acaricides in the management of the poultry red mite, Dermanyssus gallinae. At a level of 0.21 mg/cm(2), the essential oil from Eucalyptus citriodora achieved 85% mortality in D. gallinae over a 24 h exposure period in contact toxicity tests. A further two essential oils from different eucalyptus species, namely E. globulus and E. radiata, provided significantly (P gallinae. It may therefore be the case that the complexity of an essential oil's chemical make up plays an important role in dictating the toxicity of that oil to pests such as D. gallinae.

  17. Study of acaricide stability in honey. Characterization of amitraz degradation products in honey and beeswax.

    Science.gov (United States)

    Korta, E; Bakkali, A; Berrueta, L A; Gallo, B; Vicente, F; Kilchenmann, V; Bogdanov, S

    2001-12-01

    A study on the possible degradation of amitraz, bromopropylate, coumaphos, chlordimeform, cymiazole, flumethrin, and tau-fluvalinate during the storage of honey was carried out by HPLC. Except amitraz, the other acaricides are stable in this medium for at least 9 months. Degradation studies of amitraz in honey and beeswax were carried out; the degradation products detected in both matrices were 2,4-dimethylphenylformamide (DMF) and N-(2,4-dimethylphenyl)-N'-methylformamidine (DPMF). The reaction rate constants and the half-lives of the amitraz degradation in honey and wax were calculated. Amitraz was nearly completely degraded within 1 day in beeswax and within 10 days in honey. When amitraz-spiked combs are recycled into new beeswax, DMF was found to be the principal degradation product left in pure wax.

  18. Design and synthesis of novel diphenyl oxalamide and diphenyl acetamide derivatives as anticonvulsants.

    Science.gov (United States)

    Nikalje, Anna Pratima G; Ghodke, Mangesh; Girbane, Amol

    2012-01-01

    A series of novel N(1) -substituted-N(2) ,N(2) -diphenyl oxalamides 3a-l were synthesized in good yield by stirring diphenylcarbamoyl formyl chloride (2) and various substituted aliphatic, alicyclic, aromatic, heterocyclic amines in DMF and K(2) CO(3) . Also 2-substituted amino-N,N-diphenylacetamides 5a-m were designed by pharmacophore generation and synthesized by stirring 2-chloro-N,N-diphenylacetamide (4) and various substituted amines in acetone using triethyl amine as a catalyst. All the synthesized compounds were screened for anticonvulsant activity in Swiss albino mice by MES and ScPTZ induced seizure tests. Neurotoxicity screening and behavioral testing was also carried out. Some of the synthesized test compounds were found to be more potent than the standard drug.

  19. In vitro acaricidal properties of Semecarpus anacardium fruit and Datura stramonium leaf extracts against acaricide susceptible (IVRI-I line) and resistant (IVRI-V line) Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Ghosh, Srikant; Tiwari, Shashi Shankar; Srivastava, Sharad; Kumar, Sachin; Sharma, Anil Kumar; Nagar, Gaurav; Kumar, K G Ajith; Kumar, Rajesh; Rawat, A K S

    2015-08-01

    In an attempt to identify plants having anti-tick properties, the 95% ethanolic and 50% hydro-ethanolic extracts of the fruits of Semecarpus anacardium and leaves of Datura stramonium were evaluated against reference tick lines of Rhipicephalus (Boophilus) microplus. The 95% ethanolic extracts of S. anacardium and D. stramonium caused 50% and 20% mortality, respectively, within 72 h of treatment by adult immersion test. The LC90 value of the ethanolic fruit extract of S. anacardium was determined as 13.5% (CI 12.05-15.12). The extract was also found efficacious (73.3%±3.3%) against the multi-acaricide-resistant IVRI-V line of R.(B.) microplus. The S. anacardium extract significantly affected the reproductive physiology of treated ticks by inhibiting the oviposition and was found safe. The HPTLC fingerprinting profile revealed the presence of pyrocatechol as a marker compound. The acaricidal property of S. anacardium against chemical acaricide-resistant R. (B.) microplus was discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Determination of synthetic acaricides residues in beeswax by high-performance liquid chromatography with photodiode array detector.

    Science.gov (United States)

    Adamczyk, Sabine; Lázaro, Regina; Pérez-Arquillué, Consuelo; Herrera, Antonio

    2007-01-02

    A multiresidue HPLC method for identification and quantification of the synthetic acaricides fluvalinate, coumaphos, bromopropylate and its metabolite 4,4'-dibromobenzophenone in beeswax has been developed. Different techniques were tested and modified. The method consists of a sample preparation with isooctane followed by solid phase extraction using Florisil columns. Determination of the synthetic acaricides is achieved by HPLC with a photodiode array detector. Analytical performance of the proposed method, including sensitivity, accuracy and precision was satisfactory. The LOD for the analytes varied between 0.1 and 0.2 microg g(-1) wax and the recoveries between 70 and 110%. Relative standard deviation of the repeatability of the method is <15% and reproducibility is <31%.

  1. Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

    Institute of Scientific and Technical Information of China (English)

    SAAD El-Zemity; HUSSIEN Rezk; SAHER Farok; AHMED Zaitoon

    2006-01-01

    The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC50 of either essential oils or monoterpenoids against the mite was time dependant. The LC50 values were decreased by increasing of exposure time. Clove,matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids,cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus.

  2. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  3. Evaluation of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) resistance to different acaricide formulations using samples from Brazilian properties

    OpenAIRE

    2016-01-01

    Abstract The Rhipicephalus (Boophilus) microplus tick is responsible for considerable economic losses in Brazil, causing leather damage, weight loss and reduced milk production in cattle and results in the transmission of pathogens. Currently, the main method for controlling this tick is using acaricides, but their indiscriminate use is one of the major causes of resistance dissemination. In this study, the adult immersion test (AIT) was used to evaluate resistance in ticks from 28 properties...

  4. Synthesis of 2-aryl-3,4-dihydroisoquinolin-2-ium bromides and their in vitro acaricidal activity against Psoroptes cuniculi.

    Science.gov (United States)

    Ma, Yan-Ni; Yang, Xin-Juan; Pan, Le; Hou, Zhe; Geng, Hui-Ling; Song, Xiao-Ping; Zhou, Le; Miao, Fang

    2013-01-01

    By employing sanguinarine, a natural active quaternary isoquinoline alkaloid, as a model molecule, a series of structurally simple quaternary 2-aryl-3,4-dihydroisoquinolin-2-ium compounds were designed and synthesized and evaluated for in vitro acaricidal activity against P. cuniculi. A new approach towards the title compounds was developed with isochroman as starting material. The results showed that 22 of 24 tested compounds displayed the activity in varying degrees at 0.4 mg/mL. Fourteen compounds were significantly more effective than ivermectin, a standard acaricide, and 6-methoxy dihydrosanguinarine, a derivative of sanguinarine (p<0.05). And their comprehensive relative activity was 1.4 to 16.5 times than that of ivermectin and 1.5 to 18.8 times than that of 6-methoxy dihydrosanguinarine. The structure-activity relationship indicated that the introduction of a substituent to N-benzene ring, especially halogen atom and trifluoromethyl group, led to great improvement of the activity. The position of fluorine atom, methyl group and hydroxyl group made very significant effects on the activity. It was concluded that 2-aryl-3,4-dihydroisoquinolin-2-iums are very promising candidates for the development of new isoquinoline acaricidal agents.

  5. Acaricidal activity of Thymus vulgaris oil and its main components against Tyrophagus putrescentiae, a stored food mite.

    Science.gov (United States)

    Jeong, E Y; Lim, J H; Kim, H G; Lee, H S

    2008-02-01

    The acaricidal activities of compounds derived from Thymus vulgaris (thyme) oil against Tyrophagus putrescentiae were assessed using an impregnated fabric disk bioassay, and were compared with those of the synthetic acaricides, benzyl benzoate and N,N-diethyl-m-toluamide. The observed responses differed according to dosage and chemical components. The 50% lethal dose (LD50) value of the T. vulgaris oil against T. putrescentiae was 10.2 microg/cm2. Biologically active constituents derived from T. vulgaris oil were purified by using silica gel chromatography and high-performance liquid chromatography. The structures of acaricidal components were analyzed by gas chromatography-mass spectrometry, 1H nuclear magnetic resonance (NMR), 13C NMR, 1H-13C COSY-NMR, and DEPT-NMR spectra, and were subsequently identified as carvacrol and thymol. Carvacrol was the most toxic compound with LD50 values (4.5 microg/cm2) significantly different from thymol (11.1 microg/cm2), benzyl benzoate (11.3 microg/cm2), and N,N-diethyl-m-toluamide (13.9 microg/cm2). Linalool was as toxic as was N,N-diethyl-m-toluamide. The lower LD50 of carvacrol indicates that it may be the major contributor of the toxicity of T. vulagaris oil against the stored food mite, although it only constitutes 14.2% of the oil. From this point of view, carvacrol and thymol can be very useful as potential control agents against stored food mite.

  6. Exploitation of chemical, herbal and nanoformulated acaricides to control the cattle tick, Rhipicephalus (Boophilus) microplus - A review.

    Science.gov (United States)

    Banumathi, Balan; Vaseeharan, Baskaralingam; Rajasekar, Periyannan; Prabhu, Narayanan Marimuthu; Ramasamy, Palaniappan; Murugan, Kadarkarai; Canale, Angelo; Benelli, Giovanni

    2017-09-15

    The tick Rhipicephalus (Boophilus) microplus is a key vector of bacterial and protozoan diseases causing heavy economic losses directly and indirectly in animal husbandry. In the past decades, the control of ticks faced some major issues, such as the rapid development of resistance in targeted vectors and non-target effects on human health and the environment, due to the employ of synthetic acaricides and repellents. Eco-friendly pesticides for treating and controlling animal parasites such as ticks were mainly from medicinal plants and thus they form the richest entity for manufacturing resources for drugs. Even though there are efforts made to discover reliable plant-based acaricides to control ectoparasites in animal husbandry, the effective control of R. (B.) microplus ticks still represent a major challenge in current veterinary entomology. Recently, a wide number of promising attempts have been conducted to use herbal preparations and green-fabricated nanoparticles for the control of R. (B.) microplus. The aim of this review is to critically summarize and discuss the use of herbal preparations used in ethno-veterinary as well as green-fabricated nanoparticles as novel acaricides for the control of the cattle tick R. (B.) microplus. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The Acaricidal Activity of Venom from the Jellyfish Nemopilema nomurai against the Carmine Spider Mite Tetranychus cinnabarinus

    Science.gov (United States)

    Yu, Huahua; Yue, Yang; Dong, Xiangli; Li, Rongfeng; Li, Pengcheng

    2016-01-01

    The carmine spider mite Tetranychus cinnabarinus (T. cinnabarinus) is a common polyphagous pest that attacks crops, vegetables, flowers, and so on. It is necessary to find lead compounds for developing novel, powerful, and environmentally-friendly acaricides as an alternative approach to controlling the carmine spider mite because of the serious resistance and residual agrochemicals in the environment. In addition, the study on the acaricidal activities of marine bioactive substances is comparatively deficient. In the present study, the acaricidal activity of venom (NnFV) from the jellyfish Nemopilema nomurai against the carmine spider mite T. cinnabarinus was determined for the first time. The venom had contact toxicity, and the 24-h LC50-value was 29.1 μg/mL. The mite body wall was affected by the venom, with the mite body having no luster and being seriously shrunken after 24 h. T. cinnabarinus was a potential target pest of NnFV, which had potential as a type of natural bioacaricide. The repellent activity and systemic toxicity of the venom against T. cinnabarinus were also studied. However, NnFV had no repellent activity and systemic toxicity against T. cinnabarinus. PMID:27294957

  8. Acaricide activity of leaves extracts of Sambucus australis Schltdl. (Caprifoliaceae at 2% on engorged females of Rhipicephalus (Boophilus microplus

    Directory of Open Access Journals (Sweden)

    Felipe da Silva Krawczak

    Full Text Available Parasite infections caused by Rhipicephalus (Boophilus microplus are responsible for the most of economic losses in producing-cattle countries in tropical and subtropical areas. Indiscriminate uses of chemical acaricides have contributed with the appearance of tick resistance to many drugs available in the marketplace, and it is a serious problem in the tick control. Flowers of Sambucus australis (South America, called "sabugueiro-from-Brazil", are used on infusions or decoctions forms in the folk medicine with diuretic, antipyretic, anti-inflammatory, and laxative purpose, also employed for treating respiratory diseases in human. The main goal of this study was to evaluate in vitro potential of S. australis leaves extracts as an acaricide agent. Ethanol extract at 70% has been dehydrated and a fraction was suspended in 70% ethanol or in distillated water at final concentration of 2% (0.2mg-1. Using the immersion test of engorged females the efficiency results were obtained in 34% and 66% with the leaves extract diluted in water and 70% ethanol, respectively. This study is the first report on acaricidal activity of S. australis against cattle tick. Further studies to determine the active metabolites in different stages of S. australis could aid to identify suitable extracts to be tested in the R. (B. microplus control.

  9. Acaricide treatment affects viral dynamics in Varroa destructor-infested honey bee colonies via both host physiology and mite control.

    Science.gov (United States)

    Locke, Barbara; Forsgren, Eva; Fries, Ingemar; de Miranda, Joachim R

    2012-01-01

    Honey bee (Apis mellifera) colonies are declining, and a number of stressors have been identified that affect, alone or in combination, the health of honey bees. The ectoparasitic mite Varroa destructor, honey bee viruses that are often closely associated with the mite, and pesticides used to control the mite population form a complex system of stressors that may affect honey bee health in different ways. During an acaricide treatment using Apistan (plastic strips coated with tau-fluvalinate), we analyzed the infection dynamics of deformed wing virus (DWV), sacbrood virus (SBV), and black queen cell virus (BQCV) in adult bees, mite-infested pupae, their associated Varroa mites, and uninfested pupae, comparing these to similar samples from untreated control colonies. Titers of DWV increased initially with the onset of the acaricide application and then slightly decreased progressively coinciding with the removal of the Varroa mite infestation. This initial increase in DWV titers suggests a physiological effect of tau-fluvalinate on the host's susceptibility to viral infection. DWV titers in adult bees and uninfested pupae remained higher in treated colonies than in untreated colonies. The titers of SBV and BQCV did not show any direct relationship with mite infestation and showed a variety of possible effects of the acaricide treatment. The results indicate that other factors besides Varroa mite infestation may be important to the development and maintenance of damaging DWV titers in colonies. Possible biochemical explanations for the observed synergistic effects between tau-fluvalinate and virus infections are discussed.

  10. The Acaricidal Activity of Venom from the Jellyfish Nemopilema nomurai against the Carmine Spider Mite Tetranychus cinnabarinus

    Directory of Open Access Journals (Sweden)

    Huahua Yu

    2016-06-01

    Full Text Available The carmine spider mite Tetranychus cinnabarinus (T. cinnabarinus is a common polyphagous pest that attacks crops, vegetables, flowers, and so on. It is necessary to find lead compounds for developing novel, powerful, and environmentally-friendly acaricides as an alternative approach to controlling the carmine spider mite because of the serious resistance and residual agrochemicals in the environment. In addition, the study on the acaricidal activities of marine bioactive substances is comparatively deficient. In the present study, the acaricidal activity of venom (NnFV from the jellyfish Nemopilema nomurai against the carmine spider mite T. cinnabarinus was determined for the first time. The venom had contact toxicity, and the 24-h LC50-value was 29.1 μg/mL. The mite body wall was affected by the venom, with the mite body having no luster and being seriously shrunken after 24 h. T. cinnabarinus was a potential target pest of NnFV, which had potential as a type of natural bioacaricide. The repellent activity and systemic toxicity of the venom against T. cinnabarinus were also studied. However, NnFV had no repellent activity and systemic toxicity against T. cinnabarinus.

  11. Synthesis of Diphenyl α-(Dipropoxyphosphoramido)alkyl phosphonates

    Institute of Scientific and Technical Information of China (English)

    CUI, Zhan-Wei; ZHANG, Jian-Feng; MIAO, Zhi-Wei; CHEN, Ru-Yu

    2007-01-01

    A convenient method has been developed for the synthesis of diphenyl α-(dipropoxyphosphoramido)alkylphosphonates under mild conditions, namely the reaction of dipropyl phosphoramidate (1) with a para-(un)substituted benzaldehyde or cyclicketone (2) and triphenyl phosphite (3) by a one-pot procedure with the aid of acetyl chloride.

  12. Efficient Synthesis of 2,6-Diphenyl-4-arylpyrylium Tetrafluoroborate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Four pyrylium salts, (2,6-diphenyl-4-arylpyrylium tetrafluoroborate, aryl =C6Hs, 4-MeO C6H4, 4-Me2NC6H4, 4-NO2C6H4) were synthesized efficiently and economically from acctophenone and substituted chalcones in the presence of borontrifluoride.

  13. Acaricidal activity of synthesized titanium dioxide nanoparticles using Calotropis gigantea against Rhipicephalus microplus and Haemaphysalis bispinosa

    Institute of Scientific and Technical Information of China (English)

    Sampath Marimuthu; Moorthy Iyappan; Chinnadurai Siva; Loganathan Karthik; Kokati Venkata Bhaskara Rao; Abdul Abdul Rahuman; Chidambaram Jayaseelan; Arivarasan Vishnu Kirthi; Thirunavukkarasu Santhoshkumar; Kanayairam Velayutham; Asokan Bagavan; Chinnaperumal Kamaraj; Gandhi Elango

    2013-01-01

    Objective: To assess the acaricidal activity of titanium dioxide nanoparticles (TiO2 NPs) synthesized from flower aqueous extract of Calotropis gigantea (C. gigantea) against the larvae of Rhipicephalus (Boophilus) microplus [R. (B.) microplus] and the adult of Haemaphysalis bispinosa (H. bispinosa). Methods: The lyophilized C. gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH)2 (10 mM) and magnetically stirred for 6 h. Synthesized TiO2 NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDX). The synthesised TiO2 NPs were tested against the larvae of R. (B.) microplus and adult of H. bispinosa were exposed to filter paper impregnated method. Results:XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm. The functional groups for synthesized TiO2 NPs were 1 405.19, and 1 053.45 cm-1 for-NH2 bending, primary amines and amides and 1 053.84 and 1 078.45 cm-1 for C-O. SEM micrographs of the synthesized TiO2 NPs showed the aggregated and spherical in shape. The maximum efficacy was observed in the aqueous flower extract of C. gigantea and synthesized TiO2 NPs against R. (B.) microplus (LC50=24.63 and 5.43 mg/L and r2=0.960 and 0.988) and against H. bispinosa (LC50=35.22 and 9.15 mg/L and r2=0.969 and 0.969), respectively. Conclusions: The synthesized TiO2 NPs were highly stable and had significant acaricidal activity against the larvae of R. (B.) microplus and adult of H. bispinosa. This study provides the first report of synthesized TiO2 NPs and possessed excellent anti-parasitic activity.

  14. Acaricidal effect and histological damage induced by Bacillus thuringiensis protein extracts on the mite Psoroptes cuniculi.

    Science.gov (United States)

    Dunstand-Guzmán, Emmanuel; Peña-Chora, Guadalupe; Hallal-Calleros, Claudia; Pérez-Martínez, Mario; Hernández-Velazquez, Víctor Manuel; Morales-Montor, Jorge; Flores-Pérez, Fernando Iván

    2015-05-24

    The mite Psoroptes cuniculi is a common worldwide ectoparasite and the most frequently found in rabbit farms. It causes significant economic losses on commercial rabbit breeding associated with poor leather quality, reduced conception rates, weight loss, poor growth and death. Several strategies have been proposed for the treatment of mange caused by this mite, ranging from the use of acaricides, entomopathogenic fungi, essential oils and vaccines. However, therapy and control of both human scabies and animal mange are still based mainly on the use of drugs and chemicals such as ivermectin, which involves disadvantages including genotoxic and cytotoxic effects, resistance and environmental damage. Bacillus thuringiensis is a bacterium, innocuous for human being, domestic animals and plants that produces highly biodegradable proteins, and has been used worldwide for biological control. The aim of this work was to find an alternative treatment based on biological control for scabies caused by Psoroptes cuniculi, using protein extracts from strains of Bacillus thuringiensis. P. cuniculi mites were obtained from naturally infected New Zealand rabbits, and different doses of protein from B. thuringiensis were added to the mites. We measured mortality and obtained the median lethal concentration and median lethal times. For histological analysis, the mites were fixed in 10% formalin, processed according to the paraffin embedded tissue technique. Sections were stained with hematoxylin-eosin to observe the general histological structure. We report here for the first time evidence about the in vitro acaricidal effect caused by the strain GP532 of B. thuringiensis on the mite Psoroptes cuniculi, with an LC50 of 1.3 mg/ml and a LT50 of 68 h. Histological alterations caused by B. thuringiensis on this mite, included the presence of dilated intercellular spaces in the basal membrane, membrane detachment of the peritrophic matrix and morphological alterations in columnar cells

  15. Use of fluorinated polybrominated diphenyl ethers and simplified cleanup for the analysis of polybrominated diphenyl ethers in house dust

    Science.gov (United States)

    A simple, cost-effective method is described for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust using pressurized fluid extraction, cleanup with modified silica solid phase extraction tubes, and fluorinated internal standards. There are 14 PBDE congeners inc...

  16. Bridges in Complex Networks

    CERN Document Server

    Wu, Ang-Kun; Liu, Yang-Yu

    2016-01-01

    A bridge in a graph is an edge whose removal disconnects the graph and increases the number of connected components. We calculate the fraction of bridges in a wide range of real-world networks and their randomized counterparts. We find that real networks typically have more bridges than their completely randomized counterparts, but very similar fraction of bridges as their degree-preserving randomizations. We define a new edge centrality measure, called bridgeness, to differentiate the importance of a bridge in damaging a network. We find that certain real networks have very large average and variance of bridgeness compared to their degree-preserving randomizations and other real networks. Finally, we offer an analytical framework to calculate the bridge fraction and average bridgeness for uncorrelated random networks with arbitrary degree distributions.

  17. Acaricide resistance mechanisms in Rhipicephalus (Boophilus microplus Mecanismos de resistência aos acaricidas em Rhipicephalus (Boophilus microplus

    Directory of Open Access Journals (Sweden)

    Felix David Guerrero

    2012-03-01

    Full Text Available Acaricide resistance has become widespread in countries where cattle ticks, Rhipicephalus (Boophilus microplus, are a problem. Resistance arises through genetic changes in a cattle tick population that causes modifications to the target site, increased metabolism or sequestration of the acaricide, or reduced ability of the acaricide to penetrate through the outer protective layers of the tick’s body. We review the molecular and biochemical mechanisms of acaricide resistance that have been shown to be functional in R. (B. microplus. From a mechanistic point of view, resistance to pyrethroids has been characterized to a greater degree than any other acaricide class. Although a great deal of research has gone into discovery of the mechanisms that cause organophosphate resistance, very little is defined at the molecular level and organophosphate resistance seems to be maintained through a complex and multifactorial process. The resistance mechanisms for other acaricides are less well understood. The target sites of fipronil and the macrocyclic lactones are known and resistance mechanism studies are in the early stages. The target site of amitraz has not been definitively identified and this is hampering mechanistic studies on this acaricide.A resistência aos acaricidas tornou-se amplamente difundida nos países onde os carrapatos bovinos, Rhipicephalus .Boophilus. microplus, são um problema. A resistência surge por meio de alterações genéticas em umapopulação de carrapatos que causam modificações no local de ação, aumento do metabolismo ou sequestro do acaricida, ou ainda redução na capacidade do acaricida em penetrar através das camadas protetoras do corpo do carrapato. Neste artigo, foram revisados os mecanismos moleculares e bioquímicos da resistência aos acaricidas que ocorrem em R. (B. microplus. A partir de um ponto de vista dos mecanismos envolvidos, a resistência aos piretróides tem sido caracterizada em maior grau do

  18. Management of lone star ticks (Acari: Ixodidae) in recreational areas with acaricide applications, vegetative management, and exclusion of white-tailed deer.

    Science.gov (United States)

    Bloemer, S R; Mount, G A; Morris, T A; Zimmerman, R H; Barnard, D R; Snoddy, E L

    1990-07-01

    A project on management of lone star ticks, Amblyomma americanum (L.), at Land Between the Lakes, a Tennessee Valley Authority recreational area in Kentucky-Tennessee, during 1984-1988, demonstrated the effectiveness and economics of three control technologies. Acaricide applications (chlorpyrifos at 0.28 kg [AI]/ha), vegetative management (mowing and removal of 40% overstory and 90-100% of midstory, understory, and leaf litter), and host management (white-tailed deer exclusion from a 71-ha campground with a single-line fence) provided 75, 70, and 64% mean controls of all life stages of the lone star tick, respectively. Combinations of acaricide applications + vegetative management, acaricide applications + host management, and acaricide applications + vegetative management + host management produced 94, 89, and 96% mean control of all life stages, respectively. The costs of acaricide applications (two per year), vegetative management (two mowings per year), and white-tailed deer exclusion (single-line fence) were $45, $150, and $30/ha/yr, respectively. Results of this project are used to design management strategies that could be considered for use against lone star ticks in recreational areas.

  19. Carvacrol importance in veterinary and human medicine as ecologic insecticide and acaricide

    Directory of Open Access Journals (Sweden)

    Vučinić Marijana

    2011-01-01

    Full Text Available Carvacrol is an active ingredient of essential oils from different plants, mainly from oregano and thyme species. It poseses biocidal activity agains many artropodes of the importance for veterinary and human medicine. Carvacrol acts as repelent, larvicide, insecticide and acaricide. It acts against pest artropodes such as those that serve as mechanical or biological vectors for many causal agents of viral, bacterial and parasitic diseases for animals and humans. Therefore, it may be used not only in pest arthropodes control but in vector borne diseases control, too. In the paper carvacrol bioactivity against mosquitoes, house flies, cockroaches, ticks and mites are described. Potencial modes of carvacrol action on artropodes are given, too. Carvacrol reachs its biotoxicity against arthropodes alone or in combination with other active ingredients from the same plant of its origin, such as tymol, cymen or others. The paper explains reasons for frequently investigations on essential oils and other natural products of plant origin to their biotoxicity against food stored pest or pest of medicinal importance, as well as, needs for their use in agriculture, veterinary and human medicine.

  20. Acaricidal activity of Cymbopogon citratus and Azadirachta indica against house dust mites

    Institute of Scientific and Technical Information of China (English)

    Azima Laili Hanifah; Siti Hazar Awang; Ho Tze Ming; Suhaili Zainal Abidin; Maizatul Hashima Omar

    2011-01-01

    Objective: To examine the acaricidal effects of the essential oil of Cymbopogon citratus leaf extract (lemongrass) and ethanolic Azadirachta indica leaf extract (neem) against house dust mites Dermatophagoides farinae (D. farinae) and Dermatophagoides pteronyssinus (D. pteronyssinus). Methods: Twenty-five adults mites were placed onto treated filter paper that is soaked with plant extract and been tested at different concentrations (50.00%, 25.00%, 12.50%, 6.25% and 3.13%) and exposure times (24hrs, 48hrs, 72hrs and 96 hrs). All treatments were replicated 7 times, and the experiment repeated once. The topical and contact activities of the two herbs were investigated.Results:Mortalities from lemongrass extract were higher than neem for both topical and contact activities. At 50 % concentration, both 24 hrs topical and contact exposures to lemongrass resulted in more than 91% mortalities for both species of mites. At the same concentration and exposure time, neem resulted in topical mortalities of 40.3% and 15.7% against D. pteronyssinus and D.farinae respectively; contact mortalities were 8.0% and 8.9% against the 2 mites, respectively. There was no difference in topical mortalities of D. pteronyssinus from exposure to concentrations of lemongrass and neem up to 12.50%; lemongrass was more effective than neem at the higher concentrations. Conclusions: Generally, topical mortalities of D. farinae due to lemongrass are higher than that due to neem. Contact mortalities of lemongrass are always higher that neem against both species of mites.

  1. Influence of essential oil fractionation by vacuum distillation on acaricidal activity against the cattle tick

    Directory of Open Access Journals (Sweden)

    Fernando Cidade Torres

    2012-08-01

    Full Text Available The aim of this work was to study the influence of essential oil fractionation on acaricidal activity against the cattle tick Rhipicephalus (Boophilus microplus. The citronella (Cymbopogon winterianus J. and pepper tree (Schinus molle L. essential oils were fractionated by vacuum distillation yielding fractions that were analyzed by the GC/MS. Laboratory tests were carried out to determine the effect of the total essential oil and fractions on larvae of the cattle tick R. (B. microplus. The fractions 04 and 05 of the C. winterianus essential oil were the most active showing LC50 values of 1.20 and 1.34 μL/mL, respectively. The LC50 of the total oil was 3.30 μL/mL while the effect of the fractions 01, 02 and 03 was less pronounced, with LC50 values of 4.37, 4.24 and 3.49 μL/mL, respectively. The fraction 03 of the S. molle essential oil was the most active showing LC50 value of 8.80 μL/mL while the fractions 01 and 02 did not show toxic effects on the larvae.

  2. Epidemiology, genetic divergence and acaricides of Otodectes cynotis in cats and dogs

    Directory of Open Access Journals (Sweden)

    Fayez Awadalla Salib and Taher Ahamed Baraka

    2011-06-01

    Full Text Available Otodectes cynotis mite is a common parasite of cats and dogs, survives in the ear canal and causes otitis externa, itching and severe complications. The microscopic examination of ear swabs, skin scraps and faecal samples of 289 cats and 223 dogs revealed that mono-specific and mixed infestations of Otodectes cynotis in cats were (24.56% and(6.57% while in dogs were (7.17% and (4.48% respectively. The highest rate of infestation was in young cats and the lowest was in elder dogs. The mixed infestations were found in combination with Sarcoptes, Demodex, Dermatophytes, Ticks, Fleas, Ascarids, Dipylidium and Isospora. The RAPD-PCR proved the genetic divergence between cat and dog isolates whereas they are morphologically similar. Selamectin-pour on, Doramectin-subcutaneous injection and Ivermectin-Ear drops were evaluated two weeks post treatment. The rate of success in cats were (96.66% ,(90.00% and (83.33% and in dogs were (77.77%, (75.00% and (66.66% respectively. It is concluded that Selamectin pour on is the best acaricide against Otodectes cynotis in both cats and dogs. It is also needed to prepare a vaccine in the future to prevent the infestation with Otodectes cynotis and its complications. [Vet. World 2011; 4(3.000: 109-112

  3. Acaricidal activity and repellency of essential oil from Piper aduncum and its components against Tetranychus urticae.

    Science.gov (United States)

    Araújo, Mário J C; Câmara, Cláudio A G; Born, Flávia S; Moraes, Marcílio M; Badji, César A

    2012-06-01

    The chemical composition of essential oil of leaves of Piper aduncum L., growing wild in a fragment of the Atlantic Rainforest biome in northeastern Brazil, was determined through gas chromatography-mass spectrometry. The acaricidal activity and repellency of the essential oil and its components [dillapiole (0.28 g/ml), α-humulene (0.016 g/ml), (E)-nerolidol (0.0007 g/ml) and β-caryophyllene (0.0021 g/ml)] were evaluated in the laboratory against adults of Tetranychus urticae Koch. The mites were more susceptible to the oil in fumigation tests (LC(50) = 0.01 μl/l of air) than in contact test with closed Petri dish (LC(50) = 7.17 μl/ml); mortality was reduced by approximately 50 % in the latter test. The repellent action of the oil and toxicity by fumigation and contact did not differ significantly from the positive control (eugenol). The repellent activity was attributed to the components (E)-nerolidol, α-humulene and β-caryophyllene, whereas toxicity by fumigation and contact was attributed to β-caryophyllene. The effect of Piper oil and the role of its components regarding host plant preference with a two-choice leaf disk test are also discussed.

  4. Acaricides and predatory mites against the begonia mite, Polyphagotarsonemus latus (Acari: Tarsonemidae), on Hedera helix.

    Science.gov (United States)

    Audenaert, Joachim; Vissers, Marc; Haleydt, Bart; Verhoeven, Ruth; Goossens, Frans; Gobin, Bruno

    2009-01-01

    In recent years, the begonia mite (Polyphagotarsonemus lotus) has become an important threat to different ornamental cultures in warm greenhouses. At present there are no professional plant protection products registered in Belgium for the control of mites of the Tarsonemidae family. In a screening trial, we evaluated the efficacy of a range of different acaricides: abamectin, milbemectin, pyridaben, spirodiclofen. Based on the results of the screening trial several products were selected for a full efficacy trial following EPPO guidelines. The best control results were obtained with two products from the avermectine group: abamectin and milbemectin. As growers currently have to rely solely on the use of natural enemies there is a strong need for practical evaluation of efficacies of the various predatory mite species (Amblyseius swirskii, A. cucumeris, A. andersoni) used in biological mite control. In a series of experiments, we screened the use of different species of predatory mites. The first efficacy trials on heavily infested plants at different rates of dosage and under different circumstances (temperature, dose rate, application technique) were started in May 2008. In these experiments Amblyseius swirskii showed good efficacy. But temperature was the limiting factor: the predatory mite needed a minimal temperature of 18 degrees C to obtain good results. Further research is necessary to search for predatory mites that can be used in winter conditions (lower temperatures, less light).

  5. Acaricidal activity of leaves of Morus nigra against the cattle tick Rhipicephalus microplus

    Directory of Open Access Journals (Sweden)

    A.C.S. Dantas

    Full Text Available ABSTRACT The acaricidal activity of crude ethanolic extract and fractions from the leaves of Morus nigra (Moraceae was carried out on female cattle ticks Rhipicephalus microplus, using the adult immersion test. The mortality and fertility of females exposed to different concentrations of hexane, chloroform and ethyl acetate fractions, as well as ethanolic extract of M. nigra with concentrations of 5, 10 and 25mg/ml were evaluated using three treatment groups, two control groups and triplicate tests. The study also identified the main phenolic compounds of the extract and fractions of this species by HPLC. The chloroform fraction of leaves of M. nigra (25mg/mL showed the best results for this species, obtaining 62.6% of inhibition of oviposition, 39.3% of eggs eclosion average and 65.4% of effectiveness. HPLC analysis revealed the presence of phenolic compounds, which may be related to biological activity shown by the extracts, which can be used as an alternative control against R. microplus adult tick.

  6. Studies in vitro on the relative efficacy of current acaricides for Sarcoptes scabiei var. hominis.

    Science.gov (United States)

    Walton, S F; Myerscough, M R; Currie, B J

    2000-01-01

    Resistance of Sarcoptes scabiei to various topical therapies has been described, but clinical assessment of treatment failure is problematic and in-vitro assays are generally not available. We describe a simple in-vitro analysis used to evaluate the relative efficacy of a range of topical, oral, and herbal treatments available in Australia for the treatment of scabies. S. scabiei var. hominis mites were collected from skin scrapings obtained from 7 crusted scabies patients over a period of 2 years (1997 and 1998). Larvae, nymphal instars, and adult mites were tested within 3 h of collection and continuously exposed to selected commercially available treatment products until death, with the elapsed time recorded. Neem was the only product to show little acaricidal activity. Survival curves indicated that, of the other agents, 5% permethrin (Lyclear) had the slowest killing time, with 35% of mites still alive after 3 h, and 4% still alive after 18-22 h of constant exposure. In contrast, no mites were alive after 3 h exposure to 25% benzyl benzoate (Ascabiol), 1% lindane (Quellada), 5% tea tree oil and 100-8000 ng/g of ivermectin (Equimec). Despite the slower killing time with 5% permethrin, there was no evidence of any mite tolerance in vivo or treatment failure in any patients or contact cases.

  7. Acaricidal activity of Amburana cearensis on the cattle tick Rhipicephalus (Boophilus microplus

    Directory of Open Access Journals (Sweden)

    Anne Caroline dos Santos Dantas

    2015-01-01

    Full Text Available ABSTRACT: This experiment was carried out to study the bioacaricidal activity of Amburana cearensis against engorged females of Rhipicephalus ( Boophilus microplus . The crude ethanolic extract from the leaves of A. cearensis was submitted to partition with organic solvents (hexane, chloroform and ethyl acetate in order of increasing polarity; and evaluated using three treatments at concentrations of 5, 10 and 25mg ml-1. To evaluate the acaricidal activity, engorged females were submitted to the adult immersion test. Parameters analyzed were the weight of females; weight of egg mass; percentage of hatch; reproductive efficiency; expected rate of reproduction; and efficacy. For each extract and concentrating fraction, tests were performed in triplicate. Among all fractions, the hexane (2.5% achieved the best results in all parameters analyzed: 52.7% of inhibition of oviposition; 39% of hatching rate; 3,271 index of reproductive efficiency; and 67.0% effectiveness. The extract obtained gradual dose response with increasing concentration; and could be used as an aid in the control of R. ( B. microplus therapy.

  8. Acute toxic effects of fenpyroximate acaricide on Guppy (Poecilia reticulata Peters, 1859).

    Science.gov (United States)

    Doğan, Nesli; Yazıcı, Zehra; Şişman, Turgay; Aşkin, Hakan

    2013-09-01

    Fenpyroximate (FP), an acaricide, is widely used in the prevention of acarids (mites) in fruit plant gardens. In this study, the acute toxic effects of different concentrations of FP were investigated using adult guppy (Poecilia reticulata Peters, 1859). Guppy adults were exposed to a range of FP concentrations (25, 50, 75, 100, 125, and 150 µg/L) during 48 h. Static method, which is one of the acute toxicity experiments, has been used in this study. According to probit analysis, the 48-h median lethal concentration (LC50) value of FP at 26°C was found to be 72.821 µg/L. Sublethal exposures were predetermined based on 48-h LC50 value. Guppies were exposed to low concentrations (15, 25, and 50 µg/L) of FP for 48 h. Signs of paralysis and behavior deformations were monitored every 12 h in a number of live and dead adults. Low concentrations of FP were also responsible for erratic swimming, loss of equilibrium, and being lethargic. Liver histology revealed several pathological damages including congestion, picnotic nucleus, sinusoidal dilatation, increase in melanomacrophagic centers, and endothelial degeneration. Finally, the toxicity test results provided 48-h LC50 value for FP, and low concentrations of FP can be highly detrimental to guppy adults with clear evidence of behavioral and histologic effects.

  9. Synthesis of hydroxylated and methoxylated polybrominated diphenyl ethers

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ke-wen; GAO Li-ping; CAO Jie; YU Hai-wen; ZHANG Zhang

    2009-01-01

    Hydroxylated/methoxylated polybrominated diphenyl ethers (OH/MeO-PBDEs) are not only detected as natural products, but also regarded as metabolites formed from polybrominated diphenyl ethers (PBDEs), which are widely used as flame-retardants in various materials. The aim of the present study was to synthesize authentic OH-PBDEs and MeO-PBDEs, as reference standards for environmental exploration. Twenty OH-PBDEs and their corresponding MeO-PBDEs containing three to six bromine atoms were synthesized via a trial of reactions including coupling, oxidation, bromination, methylation, etc. The products were characterized by GC-MS and 1H-NMR spectroscopy in the work. As results show, all compounds synthesized were up to 99% on purity and be reqarded as authentic standards for detecting the chemical pollutants in the emvironment.

  10. 新型高效、低毒杀螨剂产品的综述%A Review of New High Efficiency and Low Toxicity Acaricides

    Institute of Scientific and Technical Information of China (English)

    华乃震

    2016-01-01

    Pest mites lead a great loss of agriculture and forestry annually. Because of mite resistance to acaricides, the research and development of new acaricide becomes the urgent demand of agrochemical market. The development and applications of new high efficiency and low toxicity acaricides are reviewed in this paper.%螨类害虫每年都给农林业生产造成极大损失。由于螨类害虫易于产生抗药性,使常规杀螨剂药效降低,因此开发新型杀螨剂是市场的迫切需求。综述了开发新型高效、低毒杀螨剂的进展、产品和应用。

  11. [N,N-Bis(diphenyl-phosphino)isopropyl-amine]dibromidonickel(II).

    Science.gov (United States)

    Hapke, Marko; Wöhl, Anina; Peitz, Stephan; Müller, Bernd H; Spannenberg, Anke; Rosenthal, Uwe

    2009-02-06

    The title compound, [NiBr(2)(C(27)H(27)NP(2))], was synthesized by the reaction of NiBr(2)(dme) (dme is 1,2-dimethoxy-ethane) with N,N-bis-(diphenyl-phosphino)isopropyl-amine in methanol/tetra-hydro-furan. The nickel(II) center is coordinated by two P atoms of the chelating PNP ligand, Ph(2)PN(iPr)PPh(2), and two bromide ions in a distorted square-planar geometry.

  12. Genetic diversity, acaricide resistance status and evolutionary potential of a Rhipicephalus microplus population from a disease-controlled cattle farming area in South Africa.

    Science.gov (United States)

    Robbertse, Luïse; Baron, Samantha; van der Merwe, Nicolaas A; Madder, Maxime; Stoltsz, Wilhelm H; Maritz-Olivier, Christine

    2016-06-01

    The Southern cattle tick, Rhipicephalus microplus is a hematophagous ectoparasite of great veterinary and economic importance. Along with its adaptability, reproductive success and vectoring capacity, R. microplus has been reported to develop resistance to the major chemical classes of acaricides currently in use. In South Africa, the Mnisi community in the Mpumalanga region offers a unique opportunity to study the adaptive potential of R. microplus. The aims of this study therefore included characterising acaricide resistance and determining the level and pattern of genetic diversity for R. microplus in this region from one primary population consisting of 12 communal dip-stations. The level of acaricide resistance was evaluated using single nucleotide polymorphisms (SNPs) in genes that contribute to acaricide insensitivity. Additionally, the ribosomal internal transcribed spacer 2 (ITS2) gene fragments of collected individuals were sequenced and a haplotype network was constructed. A high prevalence of alleles attributed to resistance against formamidines (amitraz) in the octopamine/tyramine (OCT/Tyr) receptor (frequency of 0.55) and pyrethroids in the carboxylesterase (frequency of 0.81) genes were observed. Overall, the sampled tick population was homozygous resistant to pyrethroid-based acaricides in the voltage-gated sodium channel (VGS) gene. A total of 11 haplotypes were identified in the Mnisi R. microplus population from ITS2 analysis with no clear population structure. From these allele frequencies it appears that formamidine resistance in the Mnisi community is on the rise, as the R. microplus populations is acquiring or generating these resistance alleles. Apart from rearing multi-resistant ticks to commonly used acaricides in this community these ticks may pose future problems to its surrounding areas.

  13. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  14. Insecticidal, acaricidal and synergistic effects of soosan, Pancratium maritimum extracts and constituents.

    Science.gov (United States)

    Abbassy, M A; el-Gougary, O A; el-Hamady, S; Sholo, M A

    1998-04-01

    In assessing the pesticidal activity of soosan, P. maritimum, the bulbs and leaves were extracted using acetone/ethanol & ethanol as solvents and mosquito larvae C. pipiens, as a test organism. The actone/ethanol extract of bulbs was more toxic (LC50: 25 ppm) than that of the leaves (LC50: 75 ppm). Crude alkaloids, lycorine, terpenes & sterols and fixed oil were isolated from soosan bulb. their percentages were: 0.193, 0.02, 0.13 and 3.3%, respectively. The acetone/ethanol extract showed a strong aphicidal activity to Aphis gossypii with LC50 of 0.028% followed by lycorine, soosan oil and crude alkaloids with LC50 values of 0.07, 0.28 and 0.3% respectively. Also, the acetone/ethanol extract showed high toxicity to Spodoptera littoralis 4th instar larvae, with LD50 value of 2 Mg/larva. In addition, the crude alkaloids ethanol extract and the oil of soosan bulbs showed acaricidal activity against the two spotted spider mite, Tetranychus urticae with LC50 values of 0.2, 0.36 and 1.5%, respectively. Synergism studies on the A. gosspii indicated that lycorine, the principal alkaloid of soosan bulbs, strongly synergized, the OP insecticide cyanophos and reducing its LC50 values from 120 to 48 ppm. On the other hand, the aqueous extract of soosan bulbs synergized the toxicity of actellic and permethrin in Tribolium castaneum which reduced their LC50 values from 80 to 46 ppm and from 1000 to 550 ppm, respectively. Also, ethanol and petroleum-ether extracts synergized the toxicity of reldan and permethrin, respectively, in the same insect.

  15. Evaluation of Rhipicephalus (Boophilus microplus (Acari: Ixodidae resistance to different acaricide formulations using samples from Brazilian properties

    Directory of Open Access Journals (Sweden)

    Leandro de Oliveira Souza Higa

    2016-01-01

    Full Text Available Abstract The Rhipicephalus (Boophilus microplus tick is responsible for considerable economic losses in Brazil, causing leather damage, weight loss and reduced milk production in cattle and results in the transmission of pathogens. Currently, the main method for controlling this tick is using acaricides, but their indiscriminate use is one of the major causes of resistance dissemination. In this study, the adult immersion test (AIT was used to evaluate resistance in ticks from 28 properties located in five different states (Mato Grosso do Sul, Mato Grosso, Ceará, São Paulo, e Minas Gerais and the Distrito Federal (DF of Brazil. The resistance was found in 47.64% of the repetitions demonstrating an efficacy of less than 90% in various locations throughout the country. The larvae packet test was used to evaluate samples from ten properties in four states (Mato Grosso do Sul, Mato Grosso, Minas Gerais and Espírito Santo. Spray products belonging to the main classes of acaricides, including combination formulations, were used in both types of test. New cases of resistance were found on properties within the states of Ceará, Espírito Santo and Mato Grosso, where such resistance was not previously reported.

  16. p-Anisaldehyde: acaricidal component of Pimpinella anisum seed oil against the house dust mites Dermatophagoides farinae and Dermatophagoides pteronyssinus.

    Science.gov (United States)

    Lee, Hoi-Seon

    2004-03-01

    The acaricidal activity of anise seed oil-derived p-anisaldehyde and commercially available components of anise seed oil was examined against Dermatophagoides farinae and D. pteronyssinus and compared with those of the synthetic acaricides, benzyl benzoate and N,N-diethyl- m-toluamide (DEET). On the basis of LD 50 values, the compound most toxic to D. farinae adults was p-anisaldehyde (1.11 microg/cm2) followed by benzyl benzoate (9.32 microg/cm2), DEET (36.84 microg/cm2), 3-carene (42.10 microg/cm2), and estragol (43.23 microg/cm2). Against D. pteronyssinus adults, p-anisaldehyde (0.98 microg/cm2) was much more effective than benzyl benzoate (6.54 microg/cm2), DEET (17.79 microg/cm2), 3-carene (39.84 microg/cm 2), and estragol (40.11 microg/cm2). p-Anisaldehyde was about 8.4 and 6.7 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus adults, respectively. The results suggested that p-anisaldehyde may be useful as a lead compound for the development of new agents for the selective control of house dust mites.

  17. Effect of plant essential oils as acaricides against the poultry red mite, Dermanyssus gallinae, with special focus on exposure time.

    Science.gov (United States)

    George, D R; Olatunji, G; Guy, J H; Sparagano, O A E

    2010-04-19

    Essential oils from thyme and cade have been shown to be effective acaricides against the poultry red mite, Dermanyssus gallinae (De Geer) when tested over a 24h period. Data on the actual rate of knock-down achieved with these products is lacking and potentially important as essential oils are likely to display only short-term toxicity. When tested over periods of less than 24h, thyme essential oil killed D. gallinae relatively quickly and so may make for an effective acaricide even if the residual toxicity of this product is low. However, cade essential oil did not display such a high level of mite knock-down, suggesting it may hold less promise in D. gallinae management. Comparison of the results with those obtained elsewhere using alternative D. gallinae products further confirms the possibility that thyme essential may be useful in control of this pest. This might be especially true if thyme essential oil were employed as part of an integrated pest management approach.

  18. Acaricidal Potentials of the Terpene-rich Essential Oils of Two Iranian Eucalyptus Species against Tetranychus urticae Koch.

    Science.gov (United States)

    Ebadollahi, Asgar; Sendi, Jalal Jalali; Maroufpoor, Mostafa; Rahimi-Nasrabadi, Mehdi

    2017-03-01

    There is a rapid growth in the screening of plant materials for finding new bio-pesticides. In the present study, the essential oils of E. oleosa and E. torquata leaves were extracted using a Clevenger apparatus and their chemical profiles were investigated by Gas Chromatography-Mass Spectrometry (GC-MS). Among identified compounds, the terpenes had highest amount for both essential oils; 93.59% for E. oleosa and 97.69% for E. torquata. 1,8-Cineole (31.96%), α-pinene (15.25%) and trans-anethole (7.32%) in the essential oil of E. oleosa and 1,8-cineole (28.57%), α-pinene (15.74%) and globulol (13.11%) in the E. torquata essential oil were identified as the main components. The acaricidal activity of the essential oils of E. oleosa and E. torquata were examined using fumigation methods against the adult females of Tetranychus urticae Koch. The essential oils have potential acaricidal effects on T. urticae. The essential oil of E. oleosa with LC50 value of 2.42 µL/L air was stronger than E. torquata. A correlation between log concentration and mite mortality has been observed. Based on the results of present study, it can be stated that the essential oils of E. oleosa and E. torquata have a worthy potential in the management of T. urticae.

  19. Biofunctional constituent isolated from Citrullus colocynthis fruits and structure-activity relationships of its analogues show acaricidal and insecticidal efficacy.

    Science.gov (United States)

    Jeon, Ju-Hyun; Lee, Hoi-Seon

    2014-08-27

    The acaricidal and insecticidal potential of the active constituent isolated from Citrullus colocynthis fruits and its structurally related analogues was evaluated by performing leaf disk, contact toxicity, and fumigant toxicity bioassays against Tetranychus urticae, Sitophilus oryzae, and Sitophilus zeamais adults. The active constituent of C. colocynthis fruits was isolated by chromatographic techniques and was identified as 4-methylquinoline on the basis of spectroscopic analyses. To investigate the structure-activity relationships, 4-methylquinoline and its structural analogues were tested against mites and two insect pests. On the basis of the LC50 values, 7,8-benzoquinoline was the most effective against T. urticae. Quinoline, 8-hydroxyquinoline, 2-methylquinoline, 4-methylquinoline, 6-methylquinoline, 8-methylquinoline, and 7,8-benzoquinoline showed high insecticidal activities against S. oryzae and S. zeamais regardless of the application method. These results indicate that introduction of a functional group into the quinoline skeleton and changing the position of the group have an important influence on the acaricidal and insecticidal activities. Furthermore, 4-methylquinoline isolated from C. colocynthis fruits, along with its structural analogues, could be effective natural pesticides for managing spider mites and stored grain weevils.

  20. Laboratory assessment of acaricidal activity of Cymbopogon winterianus, Vitex negundo and Withania somnifera extracts against deltamethrin resistant Hyalomma anatolicum.

    Science.gov (United States)

    Singh, Nirbhay Kumar; Jyoti; Vemu, Bhaskar; Nandi, Abhijit; Singh, Harkirat; Kumar, Rajender; Dumka, V K

    2014-07-01

    Larval packet test was used for detection of resistance levels against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids, in the multi-host tick Hyalomma anatolicum collected from district Moga, Punjab (India). Results indicated the presence of level I resistance against deltamethrin (RF = 2.81), whereas the tick isolate was susceptible to cypermethrin (RF = 0.2). The aqueous and ethanolic extracts of leaves of Cymbopogon winterianus, Vitex negundo and Withania somnifera along with roots of Vitex negundo were assessed for their acaricidal activity against the larvae of deltamethrin resistant H. anatolicum. The efficacy was assessed by measuring per cent larval mortality and determination of LC50 values. The various ethanolic extracts produced a concentration dependent increase in larval tick mortality, whereas the aqueous extracts exhibited a much lower mortality. The highest mortality (93.7 ± 0.66 %) was observed at the 5.0 % concentration of ethanolic extract of leaves of C. winterianus and the lowest LC50 value (0.011 %) was recorded for ethanolic extracts of leaves of V. negundo. The results indicated that these plant extracts have potential to be developed as herbal acaricides.

  1. Microbial degradation of 4-monobrominated diphenyl ether with anaerobic sludge

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Yang-hsin, E-mail: yhs@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China); Chou, Hsi-Ling [Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 407, Taiwan, ROC (China); Peng, Yu-Huei [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer BDE-3 was degraded with two anaerobes in different rates. Black-Right-Pointing-Pointer Glucose addition augment the debromination efficiencies. Black-Right-Pointing-Pointer Hydrogen gas was detected and relative microbes were identified. Black-Right-Pointing-Pointer Extra-carbon source enhanced degradation partial due to H{sub 2}-generation bacteria. - Abstract: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant additives for many plastic and electronic products. Owing to their ubiquitous distribution in the environment, multiple toxicity to humans, and increasing accumulation in the environment, the fate of PBDEs is of serious concern for public safety. In this study, the degradation of 4-monobrominated diphenyl ether (BDE-3) in anaerobic sludge and the effect of carbon source addition were investigated. BDE-3 can be degraded by two different anaerobic sludge samples. The by-products, diphenyl ether (DE) and bromide ions, were monitored, indicating the reaction of debromination within these anaerobic samples. Co-metabolism with glucose facilitated BDE-3 biodegradation in terms of kinetics and efficiency in the Jhongsing sludge. Through the pattern of amplified 16S rRNA gene fragments in denatured gradient gel electrophoresis (DGGE), the composition of the microbial community was analyzed. Most of the predominant microbes were novel species. The fragments enriched in BDE-3-degrading anaerobic sludge samples are presumably Clostridium sp. This enrichment coincides with the H{sub 2} gas generation and the facilitation of debromination during the degradation process. Findings of this study provide better understanding of the biodegradation of brominated DEs and can facilitate the prediction of the fate of PBDEs in the environment.

  2. Acaricidal effects of herb essential oils against Dermatophagoides farinae and D. pteronyssinus (Acari: Pyroglyphidae) and qualitative analysis of a herb Mentha pulegium(pennyroyal).

    Science.gov (United States)

    Rim, In-Sook; Jee, Cha-Ho

    2006-06-01

    This experiment was undertaken to screen the acaricidal effects of herb essential oils (pennyroyal, ylang ylang, citronella, lemon grass, tea tree, and rosemary) at different doses (0.1, 0.05, 0.025, 0.0125, and 0.00625 microliter/cm(2)) and exposure times (5, 10, 20, 20, 30 and 60 min) on house dust mites Dermatophgoides farinae and D. pteronyssinus. The most effective acaricidal components of pennyroyal (Mentha pulegium) were analyzed using a gas chromatography-mass spectrometer (GC-MS). Of these essential oils, the most effective was pennyroyal, which is composed essentially of pulegone (> 99%), at a dose of 0.025 microliter/cm(2), which at an exposure time of 5 min killed more than 98% of house dust mites. In the pennyroyal fumigation test, the closed method was more effective than the open method and maximum acaricidal effect was 100% at 0.025 microliter/cm(2), 60 min. The results show that herb essential oils, in particular, pennyroyal was proved to have potent acaricidal activity.

  3. Evaluation of the Efficacy of Acaricides Used to Control the Cattle Tick, Rhipicephalus microplus, in Dairy Herds Raised in the Brazilian Southwestern Amazon

    Directory of Open Access Journals (Sweden)

    Luciana G. Brito

    2011-01-01

    Full Text Available The adult immersion test (AIT was used to evaluate the efficacy of acaricide molecules used for control of Rhipicephalus microplus on 106 populations collected in five municipalities in the state of Rondônia in the Brazilian South Occidental Amazon region. The analysis of the data showed that the acaricide formulations had different efficacies on the tick populations surveyed. The synthetic pyrethroids (SPs acaricides were the least effective (48.35–76.84%, followed by SP + organophosphate (OP associations (68.91–81.47% and amidine (51.35–100%. For the macrocyclic lactones (MLs, the milbemycin (94.84–100% was the most effective, followed by spinosad (93.21–100% and the avermectins (81.34–100%. The phenylpyrazole (PZ group had similar efficacy (99.90% to the MLs. Therefore, SP acaricides, including associations with OP, and formulations based on amidine presented low in vitro efficacy to control the R. microplus populations surveyed.

  4. Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae) against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806).

    Science.gov (United States)

    Politi, Flávio Augusto Sanches; Figueira, Glyn Mara; Araújo, Andréa Mendez; Sampieri, Bruno Rodrigues; Mathias, Maria Izabel Camargo; Szabó, Matias Pablo Juan; Bechara, Gervásio Henrique; Dos Santos, Lourdes Campaner; Vilegas, Wagner; Pietro, Rosemeire Cristina Linhari Rodrigues

    2012-12-17

    The tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae) is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes. The in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS), using direct injection of sample. Despite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified. This is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus.

  5. Topical Treatment of White-Tailed Deer with an Acaricide for the Control of Ixodes Scapularis (Acari: Ixodidae) in a Connecticut Lyme Borreliosis Hyperendemic Community

    Science.gov (United States)

    The 4-Poster device for the topical treatment of white-tailed deer, Odocoileus virginianus (Zimmermann), against ticks using the acaricide amitraz, was evaluated in a Lyme borreliosis endemic community in Connecticut. As part of a 5-year project from 1997 to 2002, 21–24 of the 4-Posters were distrib...

  6. A survey of fipronil- and ivermectin-resistant Rhipicephalus (Boophilus) microplus collected in Northern Mexico and the options for the management of acaricide-resistant ticks with pesticides

    Science.gov (United States)

    Six strains of Rhipicephalus (Boophilus) microplus collected from northern Mexico were surveyed for resistance to 5 classes of acaricide. All were resistant to permethrin. Two strains were resistant to amitraz and 3 were found to be resistant to coumaphos. Two strains were resistant to fipronil incl...

  7. Acaricidal Treatment of White-Tailed Deer to Control Ixodes Scapularis (Acari: Ixodidae) in a New York Lyme Disease-Endemic Community

    Science.gov (United States)

    The 4-Poster device for the topical treatment of white-tailed deer, Odocoileus virginianus (Zimmermann) against ticks using the acaricide amitraz was evaluated in a Lyme borreliosis endemic community in Connecticut. As part of a 5-year project from 1997 to 2002, 21–24 of the 4-Posters were distribut...

  8. Incidence and inheritance of resistance to METI-acaricides in European strains of the two-spotted spider mite (Tetranychus urticae) (Acari: Tetranychidae).

    Science.gov (United States)

    Devine, G J; Barber, M; Denholm, I

    2001-05-01

    A strain of Tetranychus urticae (Koch; Acari: Tetranychidae), collected from hops (Humulus humuli L; Cannabaceae) in England with a short history of tebufenpyrad use, exhibited resistance to four METI (mitochondrial electron transport inhibitor)-acaricides; tebufenpyrad, pyridaben, fenazaquin and fenpyroximate. Resistance factors for these compounds in a microimmersion assay were 46, 346, 168 and 77 respectively, and corresponded to those exhibited by a Japanese METI-acaricide-resistant reference strain. Levels of resistance remained stable without further selection, and selection with tebufenpyrad did not increase them. The UK strain was also resistant (c 6-fold) to bifenthrin. Crosses of homozygous, diploid females with hemizygous, haploid males showed that, in the UK strain, METI-acaricide resistance was paternally and maternally inherited, and was an incompletely dominant trait. Another tebufenpyrad-resistant strain from the UK, originating from a chrysanthemum nursery (Chrysanthemum foeniculaceum Giseke; Asteraceae) was collected eight months later at a site c 210 km distant from the first. These are the first published incidences of METI-acaricide resistance in Europe and implications for the future use of these compounds are discussed.

  9. Bridge Crossing Simulator

    Science.gov (United States)

    2014-10-07

    Requirement BCS Computer-controlled hydraulic actuation system to impart simulated crossing loads on an entire bridge structure undergoing fatigue test ...structure. Bridge test site with prepared embankments corresponding to the span and bank condition requirements of the bridge under test Conduct real...Center (AEC). (5) Sample size and number of crossings required. The number of required simulated crossings to conduct fatigue testing per the

  10. Electrochemical Study of Diphenyl Ether Derivatives Used as Herbicides

    Directory of Open Access Journals (Sweden)

    Amira Zaouak

    2011-01-01

    Full Text Available The electrochemical behaviour of five nitro diphenyl ethers used as herbicides is investigated in acetonitrile. A detailed study by cyclic voltammetry and exhaustive electrolysis is carried out for the anodic oxidation of 2-Chloro-6-nitro-3-phenoxyaniline (aclonifen and shows that the major oxidation product is a dimeric compound. A mechanistic scheme involving a coupling process is postulated for the electrochemical oxidation of this compound. Furthermore, the use of differential pulse voltammetry on a glassy carbon electrode permits the selective determination of aclonifen. The limit of detection is 0.6 μg/mL.

  11. Polybrominated diphenyl ethers (PBDEs) in house dust in Beijing, China.

    Science.gov (United States)

    Li, K; Fu, S

    2013-10-01

    Eleven house dust samples were collected in Beijing to quantify 42 different polybrominated diphenyl ethers (PBDEs). Total PBDEs concentrations ranged from 140 to 1,300 ng g(-1). The dominant PBDEs congener identified was BDE 209, which made up more than 70% of all PBDEs congeners. Concentrations of PBDEs in Chinese house dust were lower than in other countries. The most polluted areas were electronics shops and households. It is likely that PBDEs exposure is a potential threat for Beijing residents, particularly toddlers.

  12. Environmental analysis of higher brominated diphenyl ethers and decabromodiphenyl ethane.

    Science.gov (United States)

    Kierkegaard, Amelie; Sellström, Ulla; McLachlan, Michael S

    2009-01-16

    Methods for environmental analysis of higher brominated diphenyl ethers (PBDEs), in particular decabromodiphenyl ether (BDE209), and the recently discovered environmental contaminant decabromodiphenyl ethane (deBDethane) are reviewed. The extensive literature on analysis of BDE209 has identified several critical issues, including contamination of the sample, degradation of the analyte during sample preparation and GC analysis, and the selection of appropriate detection methods and surrogate standards. The limited experience with the analysis of deBDethane suggests that there are many commonalities with BDE209. The experience garnered from the analysis of BDE209 over the last 15 years will greatly facilitate progress in the analysis of deBDethane.

  13. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  14. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  15. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  16. In vitro assessment of the acaricidal activity of Piper longum, Piper nigrum, and Zingiber officinale extracts against Hyalomma anatolicum ticks.

    Science.gov (United States)

    Singh, Nirbhay K; Saini, S P S; Singh, Harkirat; Jyoti; Sharma, S K; Rath, S S

    2017-03-01

    Ticks and tick-borne diseases are a major constraint for the sustainable cattle industry in the tropical and subtropical regions including the Indian subcontinent. The development of resistance to most of the commonly used acaricides leads to an attempt to screen plant extracts and their combinations for their possible acaricidal activity to develop an eco-friendly tick control alternative. An alcoholic and various aqueous extracts of Piper longum, Piper nigrum and Zingiber officinale and their combinations were evaluated for acaricidal activity against the three-host ixodid tick, Hyalomma anatolicum by larval immersion test using 14-21 days old unfed larvae. The efficacy was assessed by measuring larval mortality (%) and the lethal concentrations for 50% (LC50) and 95% (LC95) with their 95% confidence limits (CL) values were estimated by applying regression equation analysis to the probit transformed data of mortality. A concentration-dependent mortality response was recorded in all extracts prepared from seeds of P. longum and P. nigrum and their combinations. The highest acaricidal property was exhibited by the alcoholic extract of P. longum seeds with the minimum LC50 and LC95 (95% CL) values of 0.071% (0.07-0.072) and 0.135% (0.13-0.14), respectively, followed by alcoholic combinations. Interestingly, no acaricidal activity was recorded in extracts prepared from the rhizome of Z. officinale. The results indicated that the ethanolic extracts of P. longum and P. nigrum and their combinations can be used effectively for tick control in an integrated format.

  17. Developmental toxicity of diphenyl ether herbicides in nestling American kestrels

    Science.gov (United States)

    Hoffman, D.J.; Spann, J.W.; LeCaptain, L.J.; Bunck, C.M.; Rattner, B.A.

    1991-01-01

    Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed for 10 consecutive days with 5 microliters/g of corn oil (controls) or one of the diphenyl ether herbicides (nitrofen, bifenox, or oxyfluorfen) at concentrations of 10, 50, 250, or 500 mg/kg in corn oil. At 500 mg/kg, nitrofen resulted in complete nestling mortality, bifenox in high (66%) mortality, and oxyfluorfen in no mortality. Nitrofen at 250 mg/kg reduced nestling growth as reflected by decreased body weight, crownrump length, and bone lengths including humerus, radiusulna, femur, and tibiotarsus. Bifenox at 250 mg/kg had less effect on growth than nitrofen, but crownrump, humerus, radiusulna, and femur were significantly shorter than controls. Liver weight as a percent of body weight increased with 50 and 250 mg/kg nitrofen. Other manifestations of impending hepatotoxicity following nitrofen ingestion included increased hepatic GSH peroxidase activity in all nitrofentreated groups, and increased plasma enzyme activities for ALT, AST, and LDHL in the 250mg/kg group. Bifenox ingestion resulted in increased hepatic GSH peroxidase activity in the 50and 250mg/kg groups. Nitrofen exposure also resulted in an increase in total plasma thyroxine (T4) concentration. These findings suggest that altricial nestlings are more sensitive to diphenyl ether herbicides than young or adult birds of precocial species.

  18. Sustainable Bridge Infrastructure Procurement

    DEFF Research Database (Denmark)

    Safi, Mohammed; Du, Guangli; Simonsson, Peter

    2016-01-01

    The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...

  19. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  20. Bridge the Gap

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2017-01-01

    This article focuses on photo projects organised for teenage refugees by the Society for Humanistic Photography (Berlin, Germany). These projects, named Bridge the Gap I (2015), and Bridge the Gap II (2016), were carried out in Berlin and brought together teenagers with refugee and German...

  1. In vitro and in vivo acaricidal activity and residual toxicity of spinosad to the poultry red mite, Dermanyssus gallinae.

    Science.gov (United States)

    George, D R; Shiel, R S; Appleby, W G C; Knox, A; Guy, J H

    2010-10-29

    This paper describes two experiments conducted to examine the acaricidal potential of spinosad against the poultry red mite, Dermanyssus gallinae (De Geer), a serious ectoparasitic pest of laying hens. Spinosad is a natural product derived from the fermentation of the micro-organism Saccharopolyspora spinosa. In vitro testing confirmed that, when applied to a galvanised metal plate to the point of run-off, spinosad was toxic to adult female D. gallinae and suggested that at an application rate of 3.88 g/L a significant residual toxicity of spinosad could be achieved for up to 21 days. A subsequent in vivo experiment in a conventional cage housing system for laying hens demonstrated the acaricidal activity and residual toxicity to D. gallinae of a single application of spinosad when applied at either 1.94 or 3.88 g/L. Residual toxicity of spinosad at both of these application rates was maintained throughout the course of the 28 day post-spray study period, with a peak in product efficacy seen 14 days after spraying. The results suggest that the greater the D. gallinae population the greater will be the toxic effect of spinosad. Although the exact reasons for this are unclear, it can be speculated that conspecifics spread the product between each other more efficiently at higher mite population densities. However, further study is warranted to confirm this possibility. Application of spinosad in vivo had no effect on hen bodyweight or egg production parameters (number and weight), suggesting that this product could be used to effectively control D. gallinae infestations whilst birds are in lay. This paper also describes a novel method for effectively and efficiently achieving replication of treatments in a single poultry house, previously unpopulated with D. gallinae. Individual groups of conventional cages were stocked with hens, seeded with D. gallinae and used as replicates. Independence of replicates was achieved by isolating cage groups from one another using a

  2. Acaricidal and Insecticidal Activities of Essential Oils against a Stored-Food Mite and Stored-Grain Insects.

    Science.gov (United States)

    Song, Ja-Eun; Kim, Jeong-Moon; Lee, Na-Hyun; Yang, Ji-Yeon; Lee, Hoi-Seon

    2016-01-01

    Twenty plant-derived oils were evaluated for their acaricidal and insecticidal activities against Sitotroga cerealella, Sitophilus oryzae, Sitophilus zeamais, and Tyrophagus putrescentiae adults, by using the fumigant and filter paper diffusion methods. Responses varied with bioassay systems, insect or mite species, plant oils, and exposure time. Based on the 50% lethal dose (LD50) values against S. oryzae and S. zeamais in the fumigant bioassay, Anethum graveolens oil (4.12 and 1.12 μg/cm(3), respectively) induced the highest mortality, followed by Achillea millefolium (21.92 and 14.91 μg/cm(3)) and Eucalyptus dives (28.02 and 24.02 μg/cm(3)) oils, respectively. The most toxic oil based on the 50% lethal concentration values against T. putrescentiae was E. dives (3.13 μg/cm(3)), followed by Melaleuca leucadendron (3.93 μg/cm(3)) and Leptospermum pertersonii (4.41 μg/cm(3)). Neroli birgard oil (1.70 μg/cm(3)) was the most toxic based on the LD50 values against S. cerealella, followed by Citrus aurantium (1.80 μg/cm(3)) and Artemisia vulgaris (1.81 μg/cm(3)). The insecticidal and acaricidal activities of the plant oils in the filter paper diffusion bioassay were similar to those in the fumigant bioassay. In comparison, A. millefolium, A. graveolens, and E. dives oils were more effective against S. oryzae and S. zeamais in the fumigant bioassay than in the contact bioassay. These results indicate that the insecticidal activity of the three plant oils against S. oryzae and S. zeamais may be due to their fumigant action. Acaricidal activities of the A. millefolium, A. graveolens, and E. dives oils against T. putrescentiae were 2.62, 1.11, and 122 times higher than that of benzyl benzoate in the contact bioassay. These results indicate that A. millefolium, A. graveolens, and E. dives oils have potential for development as agents to control stored-grain insects and mites.

  3. DETERMINATION OF ALKYLATED & SULFONATED DIPHENYL OXIDE SULFACTANT BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    Methods for the determination of the anionic surfactant Dowfax 8390 are described. Dowfax is a complex mixture of various alkylated and sulfonated diphenyl oxides. The primary component of Dowfax is monoalkylated disulfonated diphenyl oxide (MADS). This work uses ion pairing chro...

  4. Development and validation of a congener-specific photodegradation model for polybrominated diphenyl ethers

    NARCIS (Netherlands)

    Zeng, X.; Simonich, S.L.M.; Robrock, K.R.; Korytar, P.; Alvarez-Cohen, L.; Barofsky, D.F.

    2008-01-01

    With the phaseout of the manufacture of some polybrominated diphenyl ether ( PBDE) formulations, namely penta-brominated diphenyl ether (BDE) and octa-BDE, and the continued use of the deca-BDE formulation, it is important to be able to predict the photodegradation of the more highly brominated cong

  5. Tris{4-[(1,3-diphenyl-1H-pyrazol-4-ylmethylene]-41-aminobiphenyl}amine

    Directory of Open Access Journals (Sweden)

    Sandhya P. Veettil

    2010-04-01

    Full Text Available Tris{4-[(1,3-diphenyl-1H-pyrazol-4-ylmethylene]-41-aminobiphenyl}amine was synthesized from N-(4-bromophenyl-N-[(1,3-diphenyl-1H-pyrazol-4-ylmethylene]amine and tris(4-bromophenylamine based on Ullmann coupling reaction. The synthesized compound was characterized by NMR, IR, MS and elemental analysis.

  6. Acaricidal activity of Ocimum basilicum and Spilanthes acmella against the ectoparasitic tick, Rhipicephalus (Boophilus) microplus (Arachinida: Ixodidae).

    Science.gov (United States)

    Veeramani, V; Sakthivelkumar, S; Tamilarasan, K; Aisha, S O; Janarthanan, S

    2014-09-01

    The ectoparasitic tick, Rhipicephalus (Boophilus) microplus collected at various cattle farms in and around Chennai was subjected to treatment of different crude solvent extracts of leaves of Ocimum basilicum and Spilanthes acmella for acaricidal activity. Among various solvent extracts of leaves of O. basilicum and S. acmella used, chloroform extract of O. basilicum at concentrations between 6% and 10% exhibited 70% and 100% mortality of ticks when compared to control. The LC50 and LC90 values of the chloroform extract of leaves of O. basilicum treatment on the ticks after 24 h were observed as 5.46% and 7.69%. Quantitative and qualitative analysis of α- and β- carboxylesterase enzymes in the whole gut homogenate of cattle tick, R. microplus treated with chloroform extract of leaves of O. basilicum revealed higher level of activities for the enzymes. This indicated that there was an induced response in the tick, R. microplus against the toxic effects of the extract of O. basilicum.

  7. Acaricidal effect of Pelargonium roseum and Eucalyptus globulus essential oils against adult stage of Rhipicephalus (Boophilus) annulatus in vitro.

    Science.gov (United States)

    Pirali-Kheirabadi, Khodadad; Razzaghi-Abyaneh, Mehdi; Halajian, Ali

    2009-06-10

    In a laboratory trial, in west-central Iran, the acaricidal effects of the essential oils (EOs) prepared from two medicinal plants, i.e. Pelargonium roseum and Eucalyptus globulus on the adult stage of Rhipicephalus (Boophilus) annulatus were evaluated. For this purpose, the engorged females of R. (B) annulatus were exposed to two-fold serial dilutions of oils (0.31-5.0%) using a "dipping method" in vitro. The engorged ticks were immersed in different plant dilutions (eight per dilution) for 1min then each replicate was incubated in separate petri dishes at 26 degrees C and 80% relative humidity. The mortality rate for adult ticks exposed to different dilutions of P. roseum and E. globulus EO's showed a dose-dependent decrease. It was however significant only for the 2.5% and 5.0% dilutions of P. roseum EO, when compared to the non-treated control (P<0.05). The mass of produced eggs in adult female ticks exposed to both P. roseum and E. globulus EOs had decreased dose-dependently. It was significant for only 2.5% and 5.0% dilutions of P. roseum EO, comparing the non-treated control (P<0.05). The highest decrease in egg laying was reported for ticks treated with 5% dilutions of P. roseum (87.5%) and E. globosus (25%) (P<0.05). This is the first report that details the acaricidal activity of EO's obtained from P. roseum and E. globosus against R. (B) annulatus. The results show that both plants, particularly P. Roseum can be considered as potential candidates for biocontrol of R. (B) annulatus in the field.

  8. Polybrominated Diphenyl Ethers Alter Hepatic Phosphoenolpyruvate Carboxykinase Enzyme Kinetics in Male Wistar Rats: Implications for Lipid and Glucose Metabolism

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDE) are a family of lipophilic brominated flame-retardants consisting of 209 possible congeners. Three PBDE commercially-produced mixtures are decabrominated diphenyl ether (e.g. deca-BDE or DE-83R); octabrominated diphenyl ether (e.g. octa-BDE o...

  9. Substance Flow Analysis of Wastes Containing Polybrominated Diphenyl Ethers

    DEFF Research Database (Denmark)

    Vyzinkarova, Dana; Brunner, Paul H.

    2013-01-01

    , vehicles. Most EOL vehicles are exported from Vienna and pose a continental, rather than a local, problem. According to the modeling, approximately 73% of cOctaBDE reached the final sink MSW incinerator, and 17% returned back to consumption by recycling. Secondary plastics, made from WEEE, may thus contain...... establishing a new, goal-oriented data set by additional analyses of waste constituents and plastic recycling samples, as well as establishing reliable mass balances of polybrominated diphenyl ethers’ flows and stocks by means of SFA....... the fractions that reach final sinks, and (3) develop recommendations for waste management to ensure their minimum recycling and maximum transfer to appropriate final sinks. By means of substance flow analysis (SFA) and scenario analysis, it was found that the key flows of cPentaBDE stem from construction...

  10. Polybrominated diphenyl ethers in Mississippi River suspended sediment

    Energy Technology Data Exchange (ETDEWEB)

    Raff, J.; Hites, R. [Indiana Univ., Bloomington, IN (United States)

    2004-09-15

    The Mississippi River Basin drains water from 41% of the conterminous U.S. and is a valuable resource that supplies food, transportation, and irrigation to more than 95 million people of the region. Discharge and runoff from industry, agriculture, and population centers have increased the loads of anthropogenic organic compounds in the river. There has been growing concern over the rising levels of polybrominated diphenyl ethers (PBDEs) in air, sediment, biota, and humans, but there have been no studies to measure the concentrations of these chemicals in North America's largest river system. The goal of this study was to investigate the occurrence of PBDEs (15 congeners including BDE-209) and to identify possible sources within the Mississippi River Basin. We found PBDEs to be widespread throughout the region, rivaling PCBs in their extent and magnitude of contamination. We have also calculated the total amount of PBDEs released to the Gulf of Mexico in 2002.

  11. Bridge technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

  12. Bridging Humanism and Behaviorism.

    Science.gov (United States)

    Chu, Lily

    1980-01-01

    Humanistic behaviorism may provide the necessary bridge between behaviorism and humanism. Perhaps the most humanistic approach to teaching is to learn how certain changes will help students and how these changes can be accomplished. (Author/MLF)

  13. State's First Bridge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Article with details on the state's first bridge that crossed the Noxubee River adjacent to the Noxubee National Wildlife Refuge Boundary. Details also included...

  14. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  15. Germ Cell Intercellular Bridges

    Science.gov (United States)

    Greenbaum, Michael P.; Iwamori, Tokuko; Buchold, Gregory M.; Matzuk, Martin M.

    2011-01-01

    Stable intercellular bridges are a conserved feature of gametogenesis in multicellular animals observed more than 100 years ago, but their function was unknown. Many of the components necessary for this structure have been identified through the study of cytokinesis in Drosophila; however, mammalian intercellular bridges have distinct properties from those of insects. Mammalian germ cell intercellular bridges are composed of general cytokinesis components with additional germ cell–specific factors including TEX14. TEX14 is an inactive kinase essential for the maintenance of stable intercellular bridges in gametes of both sexes but whose loss specifically impairs male meiosis. TEX14 acts to impede the terminal steps of abscission by competing for essential component CEP55, blocking its interaction in nongerm cells with ALIX and TSG101. Additionally, TEX14-interacting protein RBM44, whose localization in stabile intercellular bridges is limited to pachytene and secondary spermatocytes, may participate in processes such as RNA transport but is nonessential to the maintenance of intercellular bridge stability. PMID:21669984

  16. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...... m is the longest among cable-stayed bridges for both road and railway traffic....

  17. Acaricidal activity of the essential oils from Eucalyptus citriodora and Cymbopogon nardus on larvae of Amblyomma cajennense (Acari: Ixodidae) and Anocentor nitens (Acari: Ixodidae).

    Science.gov (United States)

    Clemente, Mateus Aparecido; de Oliveira Monteiro, Caio Márcio; Scoralik, Márcio Goldner; Gomes, Fernando Teixeira; de Azevedo Prata, Márcia Cristina; Daemon, Erik

    2010-09-01

    The present study evaluated the acaricidal activity of essential oils from Eucalyptus citriodora and Cymbopogon nardus on non-engorged larvae of Amblyomma cajennense and Anocentor nitens. In order to carry out the study, six groups were formed, each concentration being a treatment (6.25%, 12.5%, 25%, and 50%, respectively) and also with the creation of a control group (distilled water) and a positive control (Deltametrine). For each treatment, approximately 100 larvae of these ticks were placed onto filter papers (2 x 2 cm) impregnated with the concentrations used to test. Next, the envelopes were closed bearing inside the filter paper with measurements of 6 x 6 cm. For each group, six repetitions were performed, and after 24 h live and dead larvae were counted. This procedure was carried out for two essential oils on the two species of ticks. For A. cajennense, the acaricide efficacy of E. citriodora oil was of 10.8%, 35.3%, 34.5%, and 53.1%, whereas the efficacy of C. nardus was of 0.0%, 0.0%, 0.0%, and 61.1% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. In relation to A. nitens, the acaricide efficacy of E. citriodora oil was of 20.1%, 84.5%, 89.2%, and 100.0%, whereas the efficacy of C. nardus was of 0.0%, 90.8%, 100.0%, and 100.0% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. The results indicate that the essential oils tested showed a promising acaricidal activity mainly on A. nitens larvae.

  18. Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806

    Directory of Open Access Journals (Sweden)

    Politi Flávio Augusto Sanches

    2012-12-01

    Full Text Available Abstract Background The tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes. Methods The in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS, using direct injection of sample. Results Despite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified. Conclusions This is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus.

  19. Acaricidal activity of oregano oil and its major component, carvacrol, thymol and p-cymene against Psoroptes cuniculi in vitro and in vivo.

    Science.gov (United States)

    Shang, Xiaofei; Wang, Yu; Zhou, Xuzheng; Guo, Xiao; Dong, Shuwei; Wang, Dongsheng; Zhang, Jiyu; Pan, Hu; Zhang, Yu; Miao, Xiaolou

    2016-08-15

    Oregano oil possesses marked antioxidant and antimicrobial activity and is widely applied in animal husbandry. In the present study, we aimed to investigate the acaricidal activities of oregano oil and its major component, carvacrol, thymol and p-cymene against Psoroptes cuniculi in vitro and in vivo. The results revealed that oregano oil exhibited significant acaricidal effects against P. cuniculi that were dose- and time-dependent response. In in vitro test, concentrations of 0.05% and 0.02% (v/v) killed all of the mites within 1h and 6h, respectively. Moreover, 0.1mg/ml (w/v) carvacrol, 0.2mg/ml (w/v) thymol and 1% p-cymene (v/v) also possessed marked acaricidal activities, and compared with the control group, elicited mean mortalities of 84.00%, 96.00% and 66% at 24h, respectively. The median lethal times (LT50) against P. cuniculi of the concentrations of 0.02%, 0.01% and 0.005% (v/v) of oregano oil, thymol, carvacrol and p-cymene were 2.171h, 11.396h, 26.102h, and 4.424h, 8.957h and 15.201h, respectively. Meanwhile, twenty naturaly infested rabbits were used to four homogeneity groups: negative control (without treatment), positive control (treated with ivermectin), group treated with 1% of oregano oil and other group with 5% of oregano oil. All the treatments were topically. After the treatment of 1% and 5% oregano oil, the P. cuniculi were completely eliminated in the rabbits, and at the end of the test (day 20), the rabbits of all treatment groups exhibited favorable mental and physical statuses. These results indicated that oregano oil could be widely applied as a potential acaricidal agent in the treatment of animal acariasis in the future.

  20. Acaricidal properties of vetiver essential oil from Chrysopogon zizanioides (Poaceae) against the tick species Amblyomma cajennense and Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

    Science.gov (United States)

    Campos, Roseane Nunes de Santana; Nascimento Lima, Cecília Beatriz; Passos Oliveira, Alexandre; Albano Araújo, Ana Paula; Fitzgerald Blank, Arie; Barreto Alves, Péricles; Nascimento Lima, Rafaely; Albano Araújo, Vinícius; Santana, Alisson Silva; Bacci, Leandro

    2015-09-15

    Ticks are arthropods widely distributed in tropical and subtropical regions, which can transmit infectious agents also responsible for zoonoses. Excessive use of conventional acaricides has resulted in the onset of drug resistance by these parasites, thus the need to use alternative methods for their control. This study evaluated the acaricidal activities of Chrysopogon zizanioides (vetiver) essential oils containing different zizanoic and khuzimol (high and low acidity) acid concentrations on Amblyomma cajennense and Rhipicephalus microplus (Acari: Ixodidae). To this aims, toxicity tests of different concentrations of examined essential oils were conducted on adult females and larval stages. Results showed that the essential oils of C. zizanioides with high and low acidity reduced oviposition of females, eggs hatch and larval survival, being more effective than some commercial products widely used to control these ectoparasites. These results indicate that the C. zizanoides essential oils are promising candidates as acaricidal agents and represent also an add value to vetiver oil with high acidity, which is commercially undervalued in the cosmetic industry.

  1. Bioactivity of Different Acaricides Against Carmine Spider Mite%常用杀螨剂对朱砂叶螨室内活性测定

    Institute of Scientific and Technical Information of China (English)

    弓文香; 王玉松

    2011-01-01

    采用盆栽幼苗喷雾法和保湿叶碟喷雾法分别测定了5种常用杀螨剂对朱砂叶螨成螨的生物活性和2种常用杀螨剂时朱砂叶螨螨卵的生物活性.结果表明,阿维菌素对朱砂叶螨成螨的活性最高,其LC50值为0.020 mg/L;噻螨酮对朱砂叶螨卵的活性最高,其EC_50值为0.213mg/L.本试验对生产上合理使用农药防治农业害螨有一定的指导意义.%This thesis tested the acaricidal activity and ovicidal activity of different acaricides against carmine spider mite chiefly. The results showed that the acaricidal activity of abamectin against carmine spider mite was the highest,LC5o was 0.020 mg/L; the ovicidal activity of hexythiazox was the highest. EC5o was 0.213 mg/L. This result has the significance of guidance in controlling agricultural spider mite.

  2. Efficacy of five selected acaricides against Tetranychus urticae (Acari: Tetranychidae) and their side effects on relevant natural enemies occurring in citrus orchards.

    Science.gov (United States)

    Urbaneja, Alberto; Pascual-Ruiz, Sara; Pina, Tatiana; Abad-Moyano, Raquel; Vanaclocha, Pilar; Montón, Helga; Dembilio, Oscar; Castañera, Pedro; Jacas, Josep A

    2008-08-01

    Three groups of natural enemies are fundamental in citrus IPM in Spain: coccinellid and phytoseiid predators and hymenopteran parasitoids. Tetranychus urticae Koch is an important pest affecting citrus, for which biological control has not yet been achieved; therefore, acaricides are commonly used to control it. The goal of this study was to measure the efficacy of different acaricides on this mite and their side effects on three natural enemies relevant for citrus (Cryptolaemus montrouzieri Mulsant, Neoseiulus californicus McGregor and Aphidius colemani Viereck). Some products proved highly effective against T. urticae and harmless to A. colemani (mineral oil, tebufenpyrad, clofentezine and fenazaquin). However, almost all products tested were slightly harmful for both the predators considered. Fenazaquin was even moderately harmful for N. californicus. Further studies, like that presented here, are necessary to gain a better understanding of integrating biological and chemical controls. When considering both efficacy and side effects on beneficial arthropods, the best options would seem to be mineral oil, tebufenpyrad and clofentezine. However, it is urgent to complete testing of the side effects of the acaricides used in citrus. This question is crucial if the fact that two recently introduced Tetranychidae are being controlled in citrus by chemical means exclusively is considered.

  3. Perturbation of spectra properties of 3,4-diphenyl thiophene by polar ...

    African Journals Online (AJOL)

    SERVER

    2007-11-19

    Nov 19, 2007 ... The UV/visible spectra of 3,4-diphenyl thiophene were obtained in various solvents (both polar and non ... Electronic spectroscopy is concerned with electron transi- ... radiation by organic molecules result in electronic excita-.

  4. Preparation and characterization of aliphatic diphenyl esters intended as precursors for polyesters

    DEFF Research Database (Denmark)

    Hvilsted, S.; Andruzzi, F.; Cerrai, P.

    1991-01-01

    An extensive number of aliphatic diphenyl esters, C6H5OOC(CH2)nCOOC6H5 (n = O,...,8,10,11,12,14), have been prepared in pure form. The crystalline melting points these esters exhibit an odd-even temperature behaviour, with the higher-melting even series (n even) displaying a minimum for n = 8 while...... based on similar data from phenyl esters, interpreted as the results of an apparent macrocyclic conformation of the larger diphenyl esters. High-performance size exclusion chromatography (s.e.c.) of diphenyl esters, phenyl esters, aromatic and linear hydrocarbons in tetrahydrofuran, toluene...... and chloroform points to specific phenyl ester-solvent interactions, which obscure a potential s.e.c. conformational analysis of the diphenyl esters....

  5. Helix-Sense-Selective Polymerization of N,N-Diphenyl(Meth)acrylamide by Anionic Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, the helix-sense-selective polymerization of N,N-diphenyl acrylamide (DPAA) and N,N-diphenyl methacrylamide(DPMAA) were studied with living helix prepolymer as anionic initiator, and the chiral optical properties of the obtained polymers were investigated too.It was shown that optically active polymers of DPAA and DPMAA could be obtained under the experimental condition, and exhibited the same screw sense as that of the prepolymer.

  6. Heterogeneous reductive dehalogenation of PCB contaminated transformer oil and brominated diphenyl ethers with zero valent iron.

    Science.gov (United States)

    Habekost, A; Aristov, N

    2012-09-01

    Reductive dechlorination and debromination of halogenated biphenyls (PCBs) and diphenyl ethers (PBDEs) occurs efficiently at moderately elevated temperatures (350-600 °C) with zero valent iron (iron powder) in a nitrogen atmosphere. The proton donors tested were waste transformer oil, iso-octane, and n-decane. Observation of production of biphenyl and diphenyl ether and their condensation products indicates that the reaction is not simple pyrolysis, but a reduction. No halogenated organic products are observed.

  7. Children's exposure to polybrominated diphenyl ethers (PBDEs) through mouthing toys.

    Science.gov (United States)

    Ionas, Alin C; Ulevicus, Jocelyn; Gómez, Ana Ballesteros; Brandsma, Sicco H; Leonards, Pim E G; van de Bor, Margot; Covaci, Adrian

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) have previously been detected in children toys, yet the risk of child exposure to these chemicals through the mouthing of toys or other items is still unknown. We aimed to expand on the current knowledge by investigating the impact of infants' mouthing activities on exposure to PBDEs present in toys. This was established by a leaching model for determining the amount PBDEs that can leach from toys into saliva in simulated conditions. The PBDE migration rate was at its highest for the 15 min low-exposure scenario incubations (198 pg/cm(2) × min) with the ERM EC-591 certified reference material (CRM) (0.17% w/w PBDEs). The leaching process was congener-dependent, since the percentage of lower brominated PBDE congeners that leached out was up to 4.5 times higher than for the heavier PBDEs. To study the scenario in which a child would mouth on a toy flame retarded with BDE 209 alone, a plastic item containing 7% BDE 209 (w/w) was also tested. The BDE 209 amounts leached out in only 15 min were higher than the amounts leached from the CRM after the 16 h incubation. For the Belgian population, the exposure scenario from mouthing on toys containing PBDEs in amounts similar to the REACH threshold was found to be lower than the exposure from mother's milk, but higher than the exposure through diet or even dust.

  8. Polybrominated diphenyl ethers in seafood products of south China.

    Science.gov (United States)

    Guo, Jian-Yang; Wu, Feng-Chang; Mai, Bi-Xian; Luo, Xiao-Jun; Zeng, Eddy Y

    2007-10-31

    South China is probably one of the heaviest polybrominated diphenyl ether (PBDE) polluted regions in the world, thanks to the presence of huge and rapidly growing electronics manufacturing industries, as well as several of the world's largest e-waste recycling sites in the region. In the present work, a wide variety of nonfish seafood products collected from South China was analyzed for PBDE residues. The concentrations of PBDEs in seafood products were highly species-specific, and the magnitude of PBDE pollution was moderate in South China compared to the global levels. Congener patterns of PBDEs in seafood samples suggested that seafood products are prone to accumulating low-brominated congeners, and possible metabolic debromination of BDE-99 to BDE-47 could occur in certain organisms, such as crabs and mantis shrimp. Generally, the congener profile was dominated by BDE-209, and to a lesser extent by BDE-47 and BDE-99, which was consistent with the fact that Deca-BDE is mass-produced in China and with previous sediment results from the same area. The occurrence of BDE-209 in aquatic species from South China suggests that BDE-209 appears to be more bioavailable than previously thought, and the environmental fate and safety of BDE-209 require further investigation and call for a thorough reassessment.

  9. Diphenyl difluoroketone: a potent chemotherapy candidate for human hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Yingjian Liang

    Full Text Available Diphenyl difluoroketone (EF24, a molecule having structural similarity to curcumin, was recently reported to inhibit proliferation of various cancer cells significantly. Here we try to determine the effect and mechanism of EF24 on hepatocellular carcinoma. 2 µM EF24 was found to inhibit the proliferation of PLC/PRF/5, Hep3B, HepG2, SK-HEP-1 and Huh 7 cell lines. However, even 8 µM EF24 treatment did not affect the proliferation of normal liver LO2 cells. Accordingly, 20 mg/kg/d EF24 inhibited the growth of the tumor xenografts conspicuously while causing no apparent change in liver, spleen or body weight. In addition, significant apoptosis and G(2/M phase cell cycle arrest were found using flow cytometry. Besides, caspases and PARP activation and features typical of apoptosis including fragmented nuclei with condensed chromatin were also observed. Furthermore, the mechanism was targeted at the reduction of nuclear factor kappa b (NF-κB pathway and the NF-κB-regulated gene products Bcl-2, COX-2, Cyclin B1. Our study has offered a strategy that EF24 being a therapeutic agent for hepatocellular carcinoma.

  10. Selective pressurized liquid extraction of polybrominated diphenyl ethers in fish.

    Science.gov (United States)

    Losada, S; Santos, F J; Galceran, M T

    2009-12-15

    A fast and simple method for the analysis of polybrominated diphenyl ethers (PBDEs) in fish samples was developed using a one-step extraction and clean-up by means of pressurized liquid extraction (PLE) combined with gas chromatography-ion trap tandem mass spectrometry (GC-ITMS-MS). The selective PLE method provided to obtain ready-to-analyse extracts without any additional clean-up step, using a sorbent as fat retainer inside the PLE cell. Several PLE operating conditions, such as solvent type, extraction temperature and time, number of cycles and type of fat retainer, were studied. Using Florisil as fat retainer, maximum recoveries of PBDEs (83-108%) with minimum presence of matrix-interfering compounds were obtained using a mixture of n-hexane:dichloromethane 90:10 (v/v) as solvent, an extraction temperature of 100 degrees C and a static extraction time of 5 min in combination with three static cycles. Quality parameters of the method were established using standards and fish samples. Limits of detection and quantification ranged from 10 to 34 pg g(-1) wet weight and between 34 and 68 pg g(-1) wet weight, respectively. In addition, good linearity (between 1 and 500 ng ml(-1)) and high precision (RSD %<15%) were achieved. The method was validated using the standard reference material SRM-1945 (whale blubber) and was then applied to the analysis of PBDEs in fish samples.

  11. Maternal-infant transfer of polybrominated diphenyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, T.; Fujimine, Y.; Watanabe, S. [Otsuka Pharmaceutical Co., Ltd., Tokushima (Japan); Nakamura, Y. [SRL Nishinihon, Fukuoka (Japan); Shimomura, H. [Shimomura OBGY Clinic, Fukuoka (Japan); Nagayama, J. [Kyushu Univ., Fukuoka (Japan)

    2004-09-15

    Polybrominated diphenyl ethers (PBDEs) are widely used brominated flame retardants (BFRs) in plastics of automobiles, textile industry, television, personal computer, electronic appliances etc. The amount of production world-wide has reached 40,000 tons in 1992. In 1992 world-wide production of PBDEs reached 40,000 tons raising serious concern over the dangers of environmental pollution by BFRs. The toxicity of PBDEs was reported to be an antagonist of thyroid-hormone (T4) and inhibition to aryl hydrocarbon (Ah) receptor. Since PBDEs are structurally similar to PCBs and therefore they work as an antagonist. Polychlorinated biphenyl (PCBs) demonstrate biological stability and high lipophilicity. As a result, PCBs used in the past and released into the environment, have been transmitted through the food chain and accumlated in the human body over time. In Japan, approximately 58,000 tons of PCBs were produced with the grade name of Kanechlor in between 1954 and 1971. In this study, all PCB congeners and 25 PBDE congeners (17, 25, 28, 30, 32, 33, 35, 37, 47, 49, 66, 71, 75, 77, 85, 99, 100, 116, 119, 126, 138, 153, 154, 155, 166) were analyzed by the method that combines high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). The purpose of this study was to investigate whether congener-specific PCBs and PBDEs were transferred from pregnant women to their infants.

  12. Bioaccumulation of Polybrominated Diphenyl Ethers by Tubifex Tubifex.

    Science.gov (United States)

    Kolar, Boris; Arnuš, Lovro; Križanec, Boštjan; Peijnenburg, Willie; Kos Durjava, Mojca

    2016-01-01

    The selective uptake of polybrominated diphenyl ethers (PBDEs) by oligochaetes makes it possible to assess the bioaccumulation of individual congeners in commercial mixtures. Twenty-one congeners from three BDE commercial mixtures (TBDE-71, TBDE-79 and TBDE-83R) and as individual congeners (BDE-77, BDE-126, BDE-198 and BDE-204) were tested on Tubifex tubifex in accordance with the OECD TG 315 "Bioaccumulation in Sediment-Dwelling Benthic Oligochaetes". All the congeners that were spiked in the sediment were detected at the end of the uptake phase and at the end of the experiment. The bioaccumulation factor (BAF), the kinetic bioaccumulation factor (BAFK) and the biotasediment accumulation factor (BSAF) were calculated, and indicate a high bioaccumulation potential for tri- to hexa-BDEs and a lower bioaccumulation potential for hepta- to deca-BDEs. The penta-homologues BDE-99 and BDE-100 showed the highest BSAFs of 4.84 and 5.85 (BAFs of 7.34 and 9.01), while the nona- and deca-BDEs exhibit bioaccumulation in up to one-order-lower concentrations. The change in the bioaccumulation potential between the group of trito hexa-BDEs and hepta- to deca-BDEs correlated with the generally accepted molecular-mass threshold for the molecular transition through biological membranes (700 g/mol).

  13. Polybrominated diphenyl ethers in birds of prey from Northern China.

    Science.gov (United States)

    Chen, Da; Mai, Bixian; Song, Jie; Sun, Quanhui; Luo, Yong; Luo, Xiaojun; Zeng, Eddy Y; Hale, Robert C

    2007-03-15

    Birds of prey from Northern China (Beijing area) were examined for polybrominated diphenyl ethers (PBDEs). A total of 47 specimens from eight different species were analyzed. Muscle and liver were analyzed separately for each bird. Kidneys were pooled by species. Common kestrels exhibited the highest PBDE levels (mean muscle and liver concentrations of 12300 and 12200 ng/g lipid weight, respectively), with maxima in an individual bird of 31700 in muscle and 40900 ng/g lw in liver. Congener profiles differed between some species, but were generally dominated by the more brominated congeners (e.g., BDE-153, -209, -183, -207). BDE-209 was especially elevated compared to other published reports. Interspecies differences in congener concentrations and profiles may be due to diet, behavior, or biotransformation capacities. BDE-209 was detected in 79.4% of the samples. Common kestrels contained the highest BDE-209 levels (mean/maxima of 2150/6220 in muscle and 2870/12200 ng/g lw in liver). BDE-209 was the dominant congener in tissues from some buzzards, scops owls, and long-eared owls. It was the second most abundant congener in common kestrels. The remarkable levels and dominance of BDE-209 may relate to significant production, usage, or disposal of deca-containing products in China. These observations reinforce the growing view that organisms using terrestrial food chains may have greater exposure to BDE-209.

  14. Sorption-desorption behavior of polybrominated diphenyl ethers in soils

    Energy Technology Data Exchange (ETDEWEB)

    Olshansky, Yaniv; Polubesova, Tamara [Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel); Vetter, Walter [Institute of Food Chemistry (170b), University of Hohenheim, Garbenstr. 28, D-70599 Stuttgart (Germany); Chefetz, Benny, E-mail: chefetz@agri.huji.ac.il [Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel)

    2011-10-15

    Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (K{sub OC}) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration. - Highlights: > BDE-15 exhibited pronounced desorption hysteresis. > BDE-15 sowed higher sorption affinity to humin as compared to the bulk soils. > Sequestration of PBDEs depends on soil organic matter constitutes other than humin. - Pronounced desorption hysteresis was observed for BDE-15 in natural soils.

  15. Uptake, translocation, and debromination of polybrominated diphenyl ethers in maize

    Institute of Scientific and Technical Information of China (English)

    Moming Zhao; Shuzhen Zhang; Sen Wang; Honglin Huang

    2012-01-01

    Uptake,translocation and debromination of three polybrominated diphenyl ethers(PBDEs),BDE-28,-47 and-99,in maize were studied in a hydroponic experiment.Roots took up most of the PBDEs in the culture solutions and more highly brominated PBDEs had a stronger uptake capability.PBDEs were detected in the stems and leaves of maize after exposure but rarely detected in the blank control plants.Furthermore,PBDE concentrations decreased from roots to stems and then to leaves,and a very clear decreasing gradient was found in segments upwards along the stem.These altogether provide substantiating evidence for the acropetal translocation of PBDEs in maize.More highly brominated PBDEs were translocated with more difficulty.Radial translocation of PBDEs from nodes to sheath inside maize was also observed.Both acropetal and radial translocations were enhanced at higher transpiration rates,suggesting that PBDE transport was probably driven by the transpiration stream.Debromination of PBDEs occurred in all parts of the maize,and debromination patterns of different parent PBDEs and in different parts of a plant were similar but with some differences.This study for the first time provides direct evidence for the acropetal translocation of PBDEs within plants,elucidates the process of PBDE transport and clarifies the debromination products of PBDEs in maize.

  16. Sex difference in polybrominated diphenyl ether concentrations of walleyes

    Science.gov (United States)

    Madenjian, Charles P.; Trombka, Autumn W.; Rediske, Richard R.; Jude, David J.; O'Keefe, James P.

    2012-01-01

    Polybrominated diphenyl ether (PBDE) concentrations were determined for mature male and mature female walleyes (Sander vitreus) sampled from the Saginaw Bay population during 2007. PBDE concentrations in prey fish caught in the Saginaw River, the primary tributary to Saginaw Bay, and in Saginaw Bay during 2005 and 2007 also were determined. Mature male and mature female walleyes averaged 70.3 ng/g and 24.8 ng/g, respectively, in ΣPBDE, which was equal to the sum of concentrations of six PBDE congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154). This sex difference was likely due to males spending more time in the Saginaw River system than females. Prey fish captured in the Saginaw River were roughly ten times higher in ΣPBDE than those caught in Saginaw Bay. BDE-47 was the predominant congener in both walleyes and prey fish, and this congener contributed about 50%, on average, to ΣPBDE. Congener profiles differed significantly between the two sexes of walleyes. In contrast, congener profiles of the prey fish did not differ significantly between the river-caught fish and the bay-caught fish. One plausible explanation for these congener profile results was that net trophic transfer efficiencies of PBDEs to walleyes from their prey were similar for all congeners except BDE-28, and that diet composition differed between the two sexes of walleyes.

  17. Pharmacology and toxicology of diphenyl diselenide in several biological models

    Directory of Open Access Journals (Sweden)

    R.M. Rosa

    2007-10-01

    Full Text Available The pharmacology of synthetic organoselenium compounds indicates that they can be used as antioxidants, enzyme inhibitors, neuroprotectors, anti-tumor and anti-infectious agents, and immunomodulators. In this review, we focus on the effects of diphenyl diselenide (DPDS in various biological model organisms. DPDS possesses antioxidant activity, confirmed in several in vitro and in vivo systems, and thus has a protective effect against hepatic, renal and gastric injuries, in addition to its neuroprotective activity. The activity of the compound on the central nervous system has been studied since DPDS has lipophilic characteristics, increasing adenylyl cyclase activity and inhibiting glutamate and MK-801 binding to rat synaptic membranes. Systemic administration facilitates the formation of long-term object recognition memory in mice and has a protective effect against brain ischemia and on reserpine-induced orofacial dyskinesia in rats. On the other hand, DPDS may be toxic, mainly because of its interaction with thiol groups. In the yeast Saccharomyces cerevisiae, the molecule acts as a pro-oxidant by depleting free glutathione. Administration to mice during cadmium intoxication has the opposite effect, reducing oxidative stress in various tissues. DPDS is a potent inhibitor of d-aminolevulinate dehydratase and chronic exposure to high doses of this compound has central effects on mouse brain, as well as liver and renal toxicity. Genotoxicity of this compound has been assessed in bacteria, haploid and diploid yeast and in a tumor cell line.

  18. Phthalates and polybrominated diphenyl ethers in retail stores

    Science.gov (United States)

    Xu, Ying; Liang, Yirui; Urquidi, Jorge R.; Siegel, Jeffrey A.

    2014-04-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories, because they are extensively used as additives in consumer products and associated with serious health concerns. This study measured six phthalate and 14 PBDE compounds inside of 12 retail stores in Texas and Pennsylvania, U.S. Phthalates and PBDEs were widely found in the retail environment, indicating that they are ubiquitous indoor air pollutants. DEP, DnBP, and DEHP were the most abundant phthalates, with DnBP showing the highest concentration (0.23 ± 0.36 μg m-3). PBDEs were dominated by BDE-28, -99, and -209, having concentrations as high as 0.85 ± 1.99 ng m-3 (BDE-99). The levels of phthalates and PBDEs measured in this study are comparable to concentrations found in previous investigations of residential buildings, with phthalates showing lower concentrations and PBDEs exhibiting higher concentrations in retail stores. The potential co-occurrence of phthalates was not as strong as that of PBDEs, suggesting that phthalates might have more diverse sources. Whole building emission rates were calculated and showed similar patterns of variations as indoor air concentrations, suggestion the diversity of indoor sources of phthalates and PBDEs in retail environments.

  19. Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

    Energy Technology Data Exchange (ETDEWEB)

    Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R., E-mail: rnicastro@cena.usp.br, E-mail: arthur@cena.usp.br [Laboratorio de Radiobiologia e Ambiente (CENA/USP), Piracicaba, SP (Brazil); Sato, Mario E., E-mail: mesato@biologico.sp.gov.br [Laboratorio de Acarologia, Instituto Biologico, Campinas, SP (Brazil)

    2011-07-01

    The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC{sub 10} values. The same trend was observed for the LC{sub 50} values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced

  20. The aesthetic composite bridge.

    Science.gov (United States)

    Feinman, R A

    1997-01-01

    New developments are constantly introduced in the search for the optimal treatment modality to restore a single anterior tooth. The patient attention has shifted to aesthetics of the restoration, biocompatibility of the dental materials utilized, conservative preparation of the teeth to be restored, and the retention of intact adjacent dentition. The learning objective of this article is to review the methods currently utilized and to present a recently introduced treatment modality--the two-component bridge, which combines the strength and resiliency of composite resin with the aesthetic advantages of porcelain. The technology of the material is reviewed, the predominantly lingual tooth preparation procedures are outlined, and the bridge try-in is described. The advantages of the two-component bridge are presented along with the contraindications and suggestions of careful case selection. Three cases with congenitally missing maxillary lateral incisors in youthful patients are presented to supplement the theoretical outline and to describe and illustrate the clinical procedure.

  1. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

      The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

  2. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  3. Acaricidal and sublethal effects of a Chenopodium-based biopesticide on the two-spotted spider mite (Acari: Tetranychidae).

    Science.gov (United States)

    Musa, Asma; Međo, Irena; Marić, Ivana; Marčić, Dejan

    2017-03-01

    Acaricidal and sublethal effects of the biopesticide Requiem(®)EC (containing an essential oil extract of Chenopodium ambrosioides near ambrosioides) on the two-spotted spider mite, Tetranychus urticae Koch, were evaluated in laboratory bioassays. The biopesticide was applied to bean leaves or leaf discs using a Potter spray tower. Acaricidal activity against eggs and immatures was evaluated in successive acute toxicity bioassays. Concentration-mortality data were subjected to probit analysis and the following LC50 values (ml/l) were calculated: 2.47 (eggs), 0.71 (larvae), 1.13 (protonymphs), 2.23 (female deutonymphs), and 6.02 (female teleiochrysalises). In adult bioassay, in which pre-ovipositional females were treated with a series of concentrations (0.31-10 ml/l), a run-off effect ranging 4-80% (after 24 h) and 8-93% (after 72 h) was observed. In two-choice bioassay, T. urticae females preferred the untreated halves of leaves over the halves treated with 1.25-10 ml/l biopesticide and they laid significantly more eggs on the untreated halves in the first 24 h and summed over 72 h. The indices of repellency and oviposition deterence ranged 11.2-77.3 and 14.8-87.9%, respectively. In age-stage two-sex life table bioassay, the females that hatched from eggs treated with 2.5 ml/l biopesticide and reached adulthood on treated leaf surface showed a significantly reduced the intrinsic rate of increase (r = 0.222), compared to the control (r = 0.317). The reduction of population growth was mainly due to a reduced preadult survival rate (0.42 ± 0.04) and extended juvenile developmental time (9.27 ± 0.11 days), compared to the control (0.93 ± 0.03 and 7.70 ± 0.06 days, respectively).

  4. In vitro acaricidal activity of Murraya koenigii (L.) Spreng (Rutaceae) extracts against synthetic pyrethroid-resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Singh, Nirbhay Kumar; Jyoti; Vemu, Bhaskar; Singh, Harkirat; Prerna, Mranalini; Daundkar, Prashant S; Sharma, S K; Dumka, V K

    2015-04-01

    Larval packet test was used for detection of resistance status against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids in Rhipicephalus (Boophilus) microplus collected from Faridkot district, Punjab (India). The slope of mortality, lethal concentration for 50 % (LC50) and resistance levels were determined from the regression graphs of probit mortality of ticks plotted against log values of increasing concentrations of cypermethrin and deltamethrin. Results indicated presence of resistance of levels I and II against cypermethrin (resistance factor (RF) = 2.82) and deltamethrin (RF = 8.44), respectively. Adult immersion test was used to assess the acaricidal activity of aqueous (MLAq), ethanol (MLE), chloroform (MLC), acetone (MLA) and hexane (MLH) extracts of leaves of Murraya koenigii against these synthetic pyrethroid (SP)-resistant engorged adult females of R. (B.) microplus by determination of per cent adult mortality, reproductive index (RI), per cent inhibition of oviposition (%IO) and hatching rate. The per cent mortality caused by various extracts at concentrations ranging from 0.625 to 10.0% varied from 0.0 to 100.0% with maximum per cent mortality of 10.0, 100.0, 70.0, 40.0 and 10.0 recorded against MLAq, MLE, MLC, MLA and MLH, respectively. Among all extracts, the highest acaricidal property against SP-resistant R. (B.) microplus was exhibited by the MLE as it showed the minimum LC50 [95% confidence limit (CL)] values of 2.97% (2.82-3.12%), followed by MLC as 10.26% (8.84-11.91 %) and MLA as 18.22% (16.18-20.52%). The average egg mass weight recorded in live ticks treated with various concentrations of different extracts was lower than the respective control group ticks and was significantly (p < 0.01) lower in ticks treated with MLH extract. However, no significant effect on hatchability of eggs of treated groups when compared to control was recorded. A significant (p < 0.05) decrease in the RI was recorded in

  5. Invitro acaricidal activity of ethnoveterinary plants and green synthesis of zinc oxide nanoparticles against Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Banumathi, Balan; Malaikozhundan, Balasubramanian; Vaseeharan, Baskaralingam

    2016-01-30

    The present study was designed to investigate the invitro acaricidal effects of seven ethnoveterinary plants, zinc acetate and green synthesized zinc oxide nanoparticles against the Southern cattle tick, Rhipicephalus (Boophilus) microplus. The selected ethnoveterinary plants were extracted using ethanol and aqueous (water) solvents at 0.02mg/ml and 0.04mg/ml concentrations. Of these seven plants, Lobelia leschenaultiana showed the highest percentage of tick mortality. The ethanol extracts of L. leschenaultiana showed 93.33% mortality at 0.04mg/ml and its LC50 was 0.05mg/ml. However, zinc acetate exhibited 70% mortality at 0.04mg/ml (LC50: 0.0192mg/ml). Further, we synthesized ZnO nanoparticle using the leaf extracts of L. leschenaultiana and zinc acetate as the precursor material to control R. (B.) microplus. The structural characterization of the synthesized ZnO nanoparticles (Ll-ZnO NPs) was performed by UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microsopy (TEM). UV-vis spectra showed the absorption band at 383nm. XRD analysis clearly showed the crystalline nature of Ll-ZnO NPs with various Bragg's reflection peaks at 100, 002, 101, 102, 110, 103, 200, 201 and 202 planes. FTIR analysis showed the possible functional groups of Ll-ZnO NPs with strong band at 3420.63 and 2922.48cm(-1). SEM and TEM analysis revealed that the Ll-ZnO NPs were spherical and hexagonal in shape with particle size ranging between 20 and 65nm. The mortality of R. (B.) microplus after treatment with Ll-ZnO NPs was 35, 57.5 and 82.5% at 0.001, 0.002 and 0.004mg/ml. On the otherhand, 100% mortality of R. (B.) microplus was observed at 0.008mg/ml (LC50: 0.0017mg/ml). The results indicated that the Ll-ZnO NPs have good acaricidal properties compared to L. leschenaultiana leaf extract and zinc acetate. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Acaricidal activity of Cymbopogon winterianus, Vitex negundo and Withania somnifera against synthetic pyrethroid resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Singh, Nirbhay Kumar; Jyoti; Vemu, Bhaskar; Nandi, Abhijit; Singh, Harkirat; Kumar, Rajender; Dumka, V K

    2014-01-01

    Detection of resistance levels against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids (SPs) against Rhipicephalus (Boophilus) microplus collected from Moga, Punjab (India) was carried out using larval packet test. Results indicated the presence of resistance of level I and III against cypermethrin (resistance factors (RF) = 4.67) and deltamethrin (RF = 34.2), respectively. Adult immersion test was used to assess the acaricidal activity of aqueous and ethanolic extracts of leaves of Cymbopogon winterianus, Vitex negundo, and Withania somnifera along with roots of V. negundo against the SP resistant engorged females of R. (B.) microplus. The efficacy of various extracts was assessed by estimation of percent adult mortality, reproductive index (RI), percent inhibition of oviposition (%IO), and hatching rate. A concentration dependent increase in tick mortality was recorded which was more marked with various ethanolic extracts, and highest mortality was recorded in ticks treated with ethanolic extract of leaves of C. winterianus. The LC50 values were determined by applying regression equation analysis to the probit transformed data of mortality for various aqueous and ethanolic extracts. Acaricidal property was recorded to be higher in ethanolic extracts, and high activity was found with the ethanolic extract of leaves of C. winterianus with LC50 (95% CL) values of 0.46% (0.35-0.59%), followed by W. somnifera as 5.21% (4.45-6.09%) and V. negundo as 7.02% (4.58-10.74%). The egg mass weight of the live ticks treated with different concentrations of the various extract was significantly (p < 0.01) lower than that of control ticks; consequently, the RI and the %IO value of the treated ticks were reduced. Further, complete inhibition of hatching was recorded in eggs laid by ticks treated with ethanolic extracts of leaves of V. negundo and aqueous extracts of leaves of W. somnifera. The results of the current study indicate that extracts of C

  7. Existing Steel Railway Bridges Evaluation

    Science.gov (United States)

    Vičan, Josef; Gocál, Jozef; Odrobiňák, Jaroslav; Koteš, Peter

    2016-12-01

    The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

  8. BUILDING "BRIDGES" WITH QUALITY ASSURANCE

    Science.gov (United States)

    The papr describes how, rather than building "bridges" across centuries, quality assurance (QA) personnel have the opportunity to build bridges across technical disciplines, between public and private organizations, and between different QA groups. As reviewers and auditors of a...

  9. The Bridges Program.

    Science.gov (United States)

    Bohnen, Elizabeth; Klie, Judy

    This report describes BRIDGES, an employment equity special measures training program developed by the City of Toronto (Ontario, Canada). It was designed to help women employees move from their traditional jobs into trades, technical or operation (TTO) jobs within their own organization. The program is a combination of classroom sessions, shop…

  10. Bridging a Cultural Gap

    Science.gov (United States)

    Leviatan, Talma

    2008-01-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

  11. Building a Straw Bridge

    Science.gov (United States)

    Teaching Science, 2015

    2015-01-01

    This project is for a team of students (groups of two or three are ideal) to design and construct a model of a single-span bridge, using plastic drinking straws as the building material. All steps of the design, construction, testing and critiquing stages should be recorded by students in a journal. Students may like to include labelled diagrams,…

  12. DOE Information Bridge

    CERN Document Server

    United States. Department of Energy. Office of Scientific and Technical Information

    DOE Information Bridge, a component of EnergyFiles, provides free, convenient, and quick access to full-text DOE research and development reports in physics, chemistry, materials, biology, environmental sciences, energy technologies, engineering, computer and information science, renewable energy, and other topics. This vast collection includes over 43,000 reports that have been received and processed by OSTI since January 1995.

  13. Bridge over troubled water?

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  14. Looking Beyond the Bridge

    DEFF Research Database (Denmark)

    Jahn, Elke; Rosholm, Michael

    We perform a comprehensive analysis of the stepping-stone effect of temporary agency employment on unemployed workers. Using the timing-of-events approach, we not only investigate whether agency employment is a bridge into regular employment but also analyze its effect on post-unemployment wages...

  15. Bridging the Technological Gap.

    Science.gov (United States)

    Lazow, Robert; And Others

    The aim of "Bridging the Technological Gap" (BTG), a federally funded demonstration project, is to use microcomputer technology in the rehabilitation of the psychiatrically disabled. Through the use of a custom designed microcomputer software package, clients receive remediation in areas of specific cognitive and behavioral deficits. The project…

  16. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

    Describes a theme cycle called "Building Bridges to China" developed for third grade students that focuses on the similarities between the lives of children and families in China and the United States. Explains that the theme cycle addresses the National Geography Standards and three of the National Council for the Social Studies standards. (CMK)

  17. Estimated crop loss due to coconut mite and financial analysis of controlling the pest using the acaricide abamectin.

    Science.gov (United States)

    Rezende, Daniela; Melo, José W S; Oliveira, José E M; Gondim, Manoel G C

    2016-07-01

    Reducing the losses caused by Aceria guerreronis Keifer has been an arduous task for farmers. However, there are no detailed studies on losses that simultaneously analyse correlated parameters, and very few studies that address the economic viability of chemical control, the main strategy for managing this pest. In this study the objectives were (1) to estimate the crop loss due to coconut mite and (2) to perform a financial analysis of acaricide application to control the pest. For this, the following parameters were evaluated: number and weight of fruits, liquid albumen volume, and market destination of plants with and without monthly abamectin spraying (three harvests). The costs involved in the chemical control of A. guerreronis were also quantified. Higher A. guerreronis incidence on plants resulted in a 60 % decrease in the mean number of fruits harvested per bunch and a 28 % decrease in liquid albumen volume. Mean fruit weight remained unaffected. The market destination of the harvested fruit was also affected by higher A. guerreronis incidence. Untreated plants, with higher A. guerreronis infestation intensity, produced a lower proportion of fruit intended for fresh market and higher proportions of non-marketable fruit and fruit intended for industrial processing. Despite the costs involved in controlling A. guerreronis, the difference between the profit from the treated site and the untreated site was 18,123.50 Brazilian Real; this value represents 69.1 % higher profit at the treated site.

  18. In vitro acaricidal activity of ethanolic and aqueous floral extracts of Calendula officinalis against synthetic pyrethroid resistant Rhipicephalus (Boophilus) microplus.

    Science.gov (United States)

    Godara, R; Katoch, R; Yadav, A; Ahanger, R R; Bhutyal, A D S; Verma, P K; Katoch, M; Dutta, S; Nisa, F; Singh, N K

    2015-09-01

    Detection of resistance levels against deltamethrin and cypermethrin in Rhipicephalus (Boophilus) microplus collected from Jammu (India) was carried out using larval packet test (LPT). The results showed the presence of resistance level II and I against deltamethrin and cypermethrin, respectively. Adult immersion test (AIT) and LPT were used to evaluate the in vitro efficacy of ethanolic and aqueous floral extracts of Calendula officinalis against synthetic pyrethroid resistant adults and larvae of R. (B.) microplus. Four concentrations (1.25, 2.5, 5 and 10 %) of each extract with four replications for each concentration were used in both the bioassays. A concentration dependent mortality was observed and it was more marked with ethanolic extract. In AIT, the LC50 values for ethanolic and aqueous extracts were calculated as 9.9 and 12.9 %, respectively. The egg weight of the live ticks treated with different concentrations of the ethanolic and aqueous extracts was significantly lower than that of control ticks; consequently, the reproductive index and the percent inhibition of oviposition values of the treated ticks were reduced. The complete inhibition of hatching was recorded at 10 % of ethanolic extract. The 10 % extracts caused 100 % mortality of larvae after 24 h. In LPT, the LC50 values for ethanolic and aqueous extracts were determined to be 2.6 and 3.2 %, respectively. It can be concluded that the ethanolic extract of C. officinalis had better acaricidal properties against adults and larvae of R. (B.) microplus than the aqueous extract.

  19. Acaricidal activity of essential oils from Lippia alba genotypes and its major components carvone, limonene, and citral against Rhipicephalus microplus.

    Science.gov (United States)

    Peixoto, Magna Galvão; Costa-Júnior, Livio Martins; Blank, Arie Fitzgerald; Lima, Aldilene da Silva; Menezes, Thays Saynara Alves; Santos, Darlisson de Alexandria; Alves, Péricles Barreto; Cavalcanti, Sócrates Cabral de Holanda; Bacci, Leandro; Arrigoni-Blank, Maria de Fátima

    2015-05-30

    The goal of the present study was to evaluate the acaricidal potential of Lippia alba essential oil, citral chemotypes (LA-10 and LA-44 genotypes) and carvone chemotypes (LA-13 and LA-57 genotypes), as well as purified citral and enantiomers of carvone and limonene. Efficacy against Rhipicephalus microplus was assessed by the larval packet and the engorged female immersion tests. Citral chemotypes had greater larvicidal activity than carvone chemotypes, and this was further supported by larvicidal and adulticidal activity of purified citral with LC50 values of 7.0 and 29.8 mg/mL, respectively. While purified enantiomers of carvone exhibited greater larvicidal activity than those of limonene, enantioselectivity of limonene was observed with R-(+) displaying significantly higher efficacy (LC50 of 31.2mg/mL) than S-(-) (LC50 of 54.5mg/mL). The essential oils and purified compounds were much less toxic toward engorged adult females, with the exception of citral, and this may be due to limited cuticular penetration.

  20. Polybrominated diphenyl ethers (PBDEs): new pollutants-old diseases.

    Science.gov (United States)

    Siddiqi, Muhammad Akmal; Laessig, Ronald H; Reed, Kurt D

    2003-10-01

    Polybrominated diphenyl ethers (PBDEs) are a class of recalcitrant and bioaccumulative halogenated compounds that have emerged as a major environmental pollutant. PBDEs are used as a flame-retardant and are found in consumer goods such as electrical equipment, construction materials, coatings, textiles and polyurethane foam (furniture padding). Similar in structure to polychlorinated biphenyls (PCBs), PBDEs resist degradation in the environment. Less brominated PBDEs like tetra-, penta- and hexa- demonstrate high affinity for lipids and can accumulate in the bodies of animals and humans. Breast milk from North American women contained much higher amounts of PBDEs than levels in breast milk from Swedish women, indicating that North American exposures to PBDEs may be particularly high. Evidence to date suggests that tetra- and penta-BDEs are likely to be the more toxic and bioaccumulative of the PBDE compounds, compared to octa- and deca-congeners. PBDEs are sold as mixtures, under names such as "pentabromodiphenyl ether" and "octabromodiphenyl ether." The pentabromo product is a mixture of tetra-BDEs and penta-BDEs in approximately equal amounts. Pentabromo consists of PBDEs that are believed to be the most toxic. This mixture has been banned by the European Union, but is still used in North America. The United States is the leading producer and user of pentabromo. In August 2003, the State of California passed a bill to phase out the use of penta- and octa-PBDE by 2008. The toxicology of PBDEs is not well understood, but PBDEs have been associated with tumors, neurodevelopmental toxicity and thyroid hormone imbalance. The neurotoxic effects of PBDEs are similar to those observed for PCBs. Children exposed to PBDEs are prone to subtle but measurable developmental problems. It is presumed that PBDEs are endocrine disruptors, but research in this area is scant. Further studies are imperative in a multitude of health and environmental disciplines to determine the

  1. Polybrominated diphenyl ether congener (BDE-100) induces mitochondrial impairment.

    Science.gov (United States)

    Pereira, Lílian Cristina; de Souza, Alecsandra Oliveira; Dorta, Daniel Junqueira

    2013-06-01

    Brominated flame retardants are used in various consumer products to increase their resistance to fire and/or high temperatures. Polybrominated diphenyl ethers (PBDEs) are representatives of this class and among the most widely used congeners, and BDE-100 is produced on a large scale. There is a lack of toxicological data about these compounds, which has recently become a matter of concern to the scientific community. The mitochondria are recognized as the main energy-producing organelles, as well as playing a vital role in the maintenance of many cell functions. Therefore, mitochondria were used in the present work as an experimental model to evaluate the effects of the BDE-100 congeners at concentrations ranging from 0.1 μM to 50 μM. The results showed that high concentrations of BDE-100 were able to induce mitochondrial alterations. It was observed that the substance had an affinity for the hydrophilic portion of the mitochondrial membrane, as monitored by ANS, inhibiting the glutamate + malate-stimulated mitochondrial respiration and also inducing dissipation of the mitochondrial membrane potential, deregulation of calcium homoeostasis and mitochondrial swelling, the latter being insensitive to cyclosporin A (CsA) but partially inhibited by Ruthenium Red and N-ethyl maleimide. In addition, a significant reduction in mitochondrial ATP content was found, but on the other hand, no oxidative stress was observed after exposure of the mitochondria to BDE-100. These results show the key role of mitochondria in the cytotoxicity induced by BDE-100.

  2. A Theoretical Study on Reductive Debromination of Polybrominated Diphenyl Ethers

    Directory of Open Access Journals (Sweden)

    Xian-Fei Huang

    2012-07-01

    Full Text Available Recent progress has been made in the reductive debromination of polybrominated diphenyl ethers (PBDEs by nanoscale zero-valent iron (nZVI. To better understand the mechanism of this reaction, seven selected BDE congeners and their anions were investigated at the density functional theory (DFT level using four different methods, including B3LYP/6-31G(d, B3LYP/6-31+G(d, B3LYP/6-31G(d,p and B3LYP/6-311G(d,p. The cleaved C–Br bonds observed in the equilibrium structures of anionic PBDEs were adopted as the probe of the susceptible debromination position of PBDEs in the presence of nZVI, and the proposed major reaction pathways based on our calculations can satisfactorily conform to the reported experimental results. The debromination preference is theoretically evaluated as meta-Br > ortho-Br > para-Br. In addition, both the calculated frontier orbital energies and adiabatic electronic affinities were found to be highly related to their experimental reductive debromination rate constants. The highest linear regression coefficient was observed in the case using the energy of lowest unoccupied molecular orbital as the molecular descriptor obtained from B3LYP/6-31G(d (R2 = 0.961, n = 7 or B3LYP/6-31G(d,p (R2 = 0.961, n = 7. The results clearly showed the evidence of an electron transfer mechanism associated with this reductive debromination reaction.

  3. Polybrominated Diphenyl Ethers in Residential Dust: Sources of Variability

    Science.gov (United States)

    Whitehead, Todd P.; Brown, F. Reber; Metayer, Catherine; Park, June-Soo; Does, Monique; Petreas, Myrto X.; Buffler, Patricia A.; Rappaport, Stephen M.

    2013-01-01

    We characterized the sources of variability for polybrominated diphenyl ethers (PBDEs) in residential dust and provided guidance for investigators who plan to use residential dust to assess exposure to PBDEs. We collected repeat dust samples from 292 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001–2007 and during 2010) using household vacuum cleaners and measured 22 PBDEs using high resolution gas chromatography-high resolution mass spectrometry. Median concentrations for individual PBDEs ranged from <0.1–2,500 ng per g of dust. For each of eight representative PBDEs, we used a random-effects model to apportion total variance into regional variability (0–11%), intra-regional between-household variability (17–50%), within-household variability over time (38–74%), and within-sample variability (0–23%) and we used a mixed-effects model to identify determinants of PBDE levels. Regional differences in PBDE dust levels were associated with residential characteristics that differed by region, including the presence of furniture with exposed or crumbling foam and the recent installation of carpets in the residence. Intra-regional differences between households were associated with neighborhood urban density, racial and ethnic characteristics, and to a lesser extent, income. For some PBDEs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PBDE exposures in studies of children’s health (e.g., the Northern California Childhood Leukemia Study). PMID:23628589

  4. Effects of Diphenyl Diselenide on Methylmercury Toxicity in Rats

    Directory of Open Access Journals (Sweden)

    Cristiane L. Dalla Corte

    2013-01-01

    Full Text Available This study investigates the efficacy of diphenyl diselenide [(PhSe2] in attenuating methylmercury- (MeHg-induced toxicity in rats. Adult rats were treated with MeHg [5 mg/kg/day, intragastrically (i.g.] and/ or (PhSe2 [1 mg/kg/day, intraperitoneally (i.p.] for 21 days. Body weight gain and motor deficits were evaluated prior to treatment, on treatment days 11 and 21. In addition, hepatic and cerebral mitochondrial function (reactive oxygen species (ROS formation, total and nonprotein thiol levels, membrane potential (ΔΨm, metabolic function, and swelling, hepatic, cerebral, and muscular mercury levels, and hepatic, cerebral, and renal thioredoxin reductase (TrxR activity were evaluated. MeHg caused hepatic and cerebral mitochondrial dysfunction and inhibited TrxR activity in liver (38,9%, brain (64,3%, and kidney (73,8%. Cotreatment with (PhSe2 protected hepatic and cerebral mitochondrial thiols from depletion by MeHg but failed to completely reverse MeHg’s effect on hepatic and cerebral mitochondrial dysfunction or hepatic, cerebral, and renal inhibition of TrxR activity. Additionally, the cotreatment with (PhSe2 increased Hg accumulation in the liver (50,5% and brain (49,4% and increased the MeHg-induced motor deficits and body-weight loss. In conclusion, these results indicate that (PhSe2 can increase Hg body burden as well as the neurotoxic effects induced by MeHg exposure in rats.

  5. Synthesis and physicochemical properties of polyhydroxylated diphenyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fu; Zhang, Xuesheng; Qu, Ruijuan; Shi, Jiaqi; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-20

    Highlights: • The experimental pK{sub a1} values of five synthesized PHODEs were determined. • The hydrogen bonds existed in PHODEs were investigated. • There exist close relationships between the thermodynamic properties and N{sub PHOS}. • The relative stability order of PHODE congeners was theoretically proposed. - Abstract: Five polyhydroxylated diphenyl ethers (PHODEs) were synthesized. The first ionization constants (pK{sub a1}) of the synthesized compounds and seven phenolic compounds were determined using potentiometric titration experiments, together with the software ACD/Labs pK{sub a} DB program (version 6.0). The compared results showed that the software could be used to predict the pK{sub a1} of all 209 PHODEs. The thermodynamic properties of 209 PHODEs were calculated using density functional theory (DFT) at the B3LYP/6-311G** level with Gaussian 09 program. The standard enthalpy of formation (Δ{sub f}H{sup θ}) and the standard Gibbs energy of formation (Δ{sub f}G{sup θ}) were obtained. Two types of hydrogen bond were found to exist in the PHODEs’ molecules. The intramolecular hydrogen bond energies were discussed. The relative stability of PHODEs isomers was proposed theoretically with the relative standard Gibbs energy of formation (Δ{sub f}G{sub R}{sup θ}). The relationships of S{sup θ}, Δ{sub f}H{sup θ} and Δ{sub f}G{sup θ} to the number and position of the hydroxyl substitution (N{sub PHOS}) were studied.

  6. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.;

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  7. The Bridges of Taishun County

    Institute of Scientific and Technical Information of China (English)

    MaJianhe

    2003-01-01

    The American film The Bridges of Madison County captured the imagination of many Chinese moviegoers with its bittersweet love story and scenes of rustic covered bridges. But the U.S. can't lay sole claim to such spectacular rural sights:China has its own county worldrenowned for unforgettable bridges.

  8. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

    Full Text Available A truck with controlled semi-active suspensions traversing a bridge is examined for benefits to the bridge structure. The original concept of a road-friendly truck was extended to a bridge-friendly vehicle, using the same optimization tools. A half-car model with two independently driven axles is coupled with simply supported bridges (beam, slab model with the span range from 5 m to 50 m. Surface profile of the bridge deck is either stochastic or in the shape of a bump or a pot in the mid-span. Numerical integration in the MATLAB/SIMULINK environment solves coupled dynamic equations of motion with optimized truck suspensions. The rear axle generates the prevailing load and to a great extent determines the bridge response. A significant decrease in contact road-tire forces is observed and the mid-span bridge deflections are on average smaller, when compared to commercial passive suspensions. 

  9. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

    We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...... proposed simulation method for one-dimensional bridges to the mulit-variate setting. First a method of simulating approzimate, but often very accurate, diffusion bridges is proposed. These approximate bridges are used as proposal for easily implementable MCMC algorithms that produce exact diffusion bridges...

  10. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As'][(4-bromo-phen-yl)diphenyl-phosphine-3κP]nona-carbonyl-1κC,2κC,3κC-triangulo-tri-ruthenium(0) chloro-form 0.3-solvate.

    Science.gov (United States)

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-16

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(18)H(14)BrP)(CO)(9)]·0.3CHCl(3), contains one mol-ecule of the triangulo-triruthenium complex and one partially occupied disordered chloro-form solvent mol-ecule. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The phosphine-substituted benzene rings make dihedral angles of 67.5 (3), 76.1 (3) and 78.1 (3)° with each other. The dihedral angles between the two benzene rings are 79.0 (4) and 81.4 (3)° for the two diphenyl-arsino groups. In the crystal packing, the mol-ecules are linked into chains along the a axis by inter-molecular C-H⋯O hydrogen bonds.

  11. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As']nona-carbonyl-1κC,2κC,3κC-[(penta-fluoro-phen-yl)diphenyl-phosphine-3κP]-triangulo-triruthenium(0) chloro-form monosolvate.

    Science.gov (United States)

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-16

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(18)H(10)F(5)P)(CO)(9)]·CHCl(3), contains one mol-ecule of the triangulo-triruthenium complex and one mol-ecule of the disordered chloro-form solvent. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate phosphine ligand bonds to the third Ru atom. Both the arsine and phosphine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The phosphine-substituted benzene rings make dihedral angles of 68.43 (15), 65.14 (14) and 89.75 (14)° with each other. The dihedral angles between the two benzene rings are 80.70 (15) and 84.53 (16)° for the two diphenyl-arsino groups. In the crystal packing, the mol-ecules are linked into a plane parallel to bc by inter-molecular C-H⋯O and C-H⋯F hydrogen bonds. Weak inter-molecular C-H⋯π inter-actions further stabilize the crystal structure.

  12. Post harvest physiconutritional changes in Kagzi limes (Citrus aurantifolia Swingle) treated with selected oil emulsions and diphenyl.

    Science.gov (United States)

    Verma, P; Dashora, L K

    2000-01-01

    Influence of oil emulsions and diphenyl on post-harvest physiconutritional changes in Kagzi limes (Citrus aurantifolia) was studied. During twelve days of storage, physiological loss in weight (PLW) and rotting were at a minimum in fruits treated with Neem (Azadirachta indica A. Juss.) oil plus diphenyl; juice content was at a maximum in mustard oil + diphenyl treated fruits. With the advancement of storage period, total soluble solids were increased while ascorbic acid and acidity of fruits decreased. Mustard oil plus diphenyl supported maximum ascorbic acid (25.60 mg/100 ml juice) and minimum total soluble solids (9.03%).

  13. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  14. Bridging Classroom Language Ethnography

    OpenAIRE

    GRENFELL, MICHAEL JAMES

    2012-01-01

    PUBLISHED Paper #5: Bridging Classroom Language Ethnography, New Literacy Studies and Bourdieu?s Social Philosophy: Principles and Practice The purpose of this paper is to analyze and synthesize the various ways that classroom language ethnography, NLS, and Bourdieu?s social philosophy, were integrated. The goal of the analysis and synthesis is to provide a fresh perspective and fruitful insights on literacy in all its manifestations that provides the foundations for a more robust...

  15. Photosensitizers in the fight against ticks: safranin as a novel photodynamic fluorescent acaricide to control the camel tick Hyalomma dromedarii (Ixodidae).

    Science.gov (United States)

    Khater, Hanem; Hendawy, Nabil; Govindarajan, Marimuthu; Murugan, Kadarkarai; Benelli, Giovanni

    2016-10-01

    Ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, livestock, and companion animals. Hyalomma dromedarii is the predominant tick species infesting camels, and its effective control is of pivotal importance. In this research, we compared the phytoefficacy of safranin (SF), a fluorescent dye applied as an acaricide for the first time, to that of tetramethrin (TM) against engorged females of H. dromedarii through in vitro immersion bioassays. Furthermore, the effect of SF exposure was evaluated on the reproductive potential of surviving tick females. Different concentrations of SF (0.03, 0.06, 0.3, 1, and 4 % w:v) and TM (0.03, 0.13, 0.5, 2, and 4 %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30 min post-treatment (PT). Photophysical properties of SF were studied, and the relative efficacy of the used light source and sunlight was calculated. Results showed that the minimum least concentration that causes 100 % acaricidal effect was 4 % PT with SF and TM, for 8 and 48 h, respectively. LC50 values 8 and 24 h PT were 0.08, 0.03 and 0.78, 0.20 %, respectively. Comparing LC50 and LC90 2 h PT, SF was 33 and 22 times more potent than TM. LT50 of 4 % SF and TM were 0.80 and 2.17 h, respectively. Treatment with the lowest concentrations of SF and TM induced reduction of the number of ovipositing females, eggs per female, ticks laying viable eggs, and hatched eggs. Overall, our results highlighted that SF is highly effective if compared to TM, allowing use to candidate it for the development of novel and safer acaricides.

  16. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    not been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL......The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has...

  17. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of acaricides against (mange and itch) mites on ruminants.

    Science.gov (United States)

    Vercruysse, J; Rehbein, S; Holdsworth, P A; Letonja, T; Peter, R J

    2006-02-28

    These guidelines have been prepared to assist in the planning, conduct and interpretation of studies for the assessment of the efficacy of acaricides against mange and itch mites on ruminants. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping and result interpretation. These guidelines also are intended to assist the investigators on how to conduct specific experiments, to provide specific information for registration authorities involved in the decision-making process, to assist in the approval and registration of new ectoparasiticides, and to facilitate the worldwide adoption of standard procedures.

  18. Erratum to: the acaricidal efficacy of peracetic acid and deltamethrin against the fowl tick, Argas persicus, infesting laying hens.

    Science.gov (United States)

    Khater, Hanem F; Seddiek, Shaker A; El-Shorbagy, Mohamed M; Ali, Ali M

    2013-10-01

    The fowl tick, Argas persicus (Oken), is of veterinary importance as a parasite of poultry and wild birds. The antitick efficacy, in vitro and in vivo, of peracetic acid (PAA) and deltamethrin (DMT) was tested separately against A. persicus through the dipping technique. PAA (0.5%) was highly efficient against soft tick larvae (A. persicus), resulting in 100 % mortality after 2 min. The lethal concentrations LC₅₀ and LC₉₅ were 0.310 and 0.503 %, respectively. The lethal time values LT₅₀ and LT₉₅ were 5.34 and 40.00 min, respectively, after treatment with PAA (0.25%). Two minutes after exposure to DMT, LC₅₀ and LC₉₅ values were 0.0033 and 0.0052% (33.204 and 51.527 mg/L), respectively. The LT₅₀ and LT₉₅ values were 27.03 and 305.46 min, respectively, after treatment with 0.0025% DMT (25 mg/L). After dipping in PAA (0.5%), the chickens did not show respiratory signs or inflammation on the eyes and/or skin. By contrast, temporary coughing, sneezing, and ocular inflammations without dermatitis were observed in chickens dipped in DMT (0.005 % or 50 mg /L). Seven days posttreatment (PT), the reduction in the percentages of A. persicus infesting laying hens were 99.15 and 63.42% after dipping in PAA and DMT, respectively. However, complete elimination of the number of ticks occurred after 28 days PT with DMT. PAA inhibits molting effectively (28%) when compared with that of DMT (52%). Results indicated that PAA is a more potent and promising acaricide against A. persicus (in vitro and in vivo) than DMT.

  19. The acaricidal efficacy of peracetic acid and deltamethrin against the fowl tick, Argas persicus, infesting laying hens.

    Science.gov (United States)

    Khater, Hanem F; Seddiek, Shaker A; El-Shorbagy, Mohamed M; Ali, Ali M

    2013-01-01

    The fowl tick, Argas persicus (Oken), is of veterinary importance as a parasite of poultry and wild birds. The antitick efficacy, in vitro and in vivo, of peracetic acid (PAA) and deltamethrin (DMT) was tested separately against A. persicus through the dipping technique. PAA (0.5 %) was highly efficient against soft tick larvae (A. persicus), resulting in 100 % mortality after 2 min. The lethal concentrations LC(50) and LC(95) were 0.310 and 0.503 %, respectively. The lethal time values LT(50) and LT(95) were 5.34 and 40.00 min, respectively, after treatment with PAA (0.25 %). Two minutes after exposure to DMT, LC(50) and LC(95) values were 0.033 and 0.052 % (33.204 and 51.527 mg/L), respectively. The LT(50) and LT(95) values were 27.03 and 305.46 min, respectively, after treatment with 0.025 % DMT (25 mg/L). After dipping in PAA (0.5 %), the chickens did not show respiratory signs or inflammation on the eyes and/or skin. By contrast, temporary coughing, sneezing, and ocular inflammations without dermatitis were observed in chickens dipped in DMT (0.05 % or 50 mg /L). Seven days posttreatment (PT), the reduction in the percentages of A. persicus infesting laying hens were 99.15 and 63.42 % after dipping in PAA and DMT, respectively. However, complete elimination of the number of ticks occurred after 28 days PT with DMT. PAA inhibits molting effectively (28 %) when compared with that of DMT (52 %). Results indicated that PAA is a more potent and promising acaricide against A. persicus (in vitro and in vivo) than DMT.

  20. Acaricidal, pediculicidal and larvicidal activity of synthesized ZnO nanoparticles using Momordica charantia leaf extract against blood feeding parasites.

    Science.gov (United States)

    Gandhi, P Rajiv; Jayaseelan, C; Mary, R Regina; Mathivanan, D; Suseem, S R

    2017-10-01

    The aim of the present study was to evaluate the acaricidal, pediculicidal and larvicidal effect of synthesized zinc oxide nanoparticles (ZnO NPs) using Momordica charantia leaf extract against the larvae of Rhipicephalus (Boophilus) microplus, adult of Pediculus humanus capitis, and the larvae of Anopheles stephensi, Culex quinquefasciatus. The ZnO NPs were characterized by using UV, XRD, FTIR and SEM-EDX. The SEM image confirms that the synthesized nanoparticles were spherical in shape with a size of 21.32 nm. The results of GC-MS analysis indicates the presence of the major compound of Nonacosane (C29H60) in the M. charantia leaf extract. Cattle tick, head lice and mosquito larvae were exposed to a varying concentrations of the synthesized ZnO NPs and M. charantia leaf extract for 24 h. Compared to the leaf aqueous extract, biosynthesized ZnO NPs showed higher toxicity against R. microplus, P. humanus capitis, An. stephensi, and Cx. Quinquefasciatus with the LC50 values of 6.87, 14.38, 5.42, and 4.87 mg/L, respectively. The findings revealed that synthesized ZnO NPs possess excellent anti-parasitic activity. These results suggest that the green synthesized ZnO NPs has the potential to be used as an ideal ecofriendly approach for the control of R. microplus, P. humanus capitis and the mosquito larvae of An. Stephensi and Cx. quinquefasciatus. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Triclosan and Hydroxylated Polybrominated Diphenyl Ethers in Lake and Esturaine Sediments

    Science.gov (United States)

    Arnold, W. A.; Kerrigan, J. F.; McNeill, K.; Erickson, P. R.; Grandbois, M.

    2014-12-01

    Halogenated diphenyl ethers are a class of emerging contaminants that includes the antibacterial compound triclosan and the flame retardant polybrominated diphenyl ethers (PBDEs). Both triclosan and hydroxylated polybrominated diphenyl ethers (OH-BDEs) are known to form dioxins when exposed to sunlight in aqueous solution. Thus, it is important to understand the sources and presence of these compounds in the environment, especially because OH-BDEs are breakdown products of PBDEs and also naturally produced compounds. In this work, the levels of OH-BDEs were determined in lake sediments from Minnesota and esturaine sediments from San Francisco Bay. Both surface sediments over a broad spatial area and sediment cores were collected and analyzed. Triclosan was used as a marker of wastewater as a source of the targeted emerging contaminants. The relationship between triclosan and OH-BDE levels provides insight into the importance of natural and anthropogenic influences on the levels of OH-BDEs.

  2. Rigid-rod polyamides and polyimides derived from 4,3 ''-diamino-2 ',6 '-diphenyl- or di(4-biphenylyl)-p-terphenyl and 4-amino-4 ''-carboxy-2 ',6 '-diphenyl-p-terphenyl

    NARCIS (Netherlands)

    Spiliopoulos, IK; Mikroyannidis, JA; Tsivgoulis, GM

    1998-01-01

    4,3 "-Diamino-2',6'-diphenyl- or di(4-biphenylyl)p-terphenyl (3a or 3b) and 4-amino-4 "-carboxy-2',6'-diphenyl-p-terphenyl (6) were synthesized through pyrylium salts and used for the preparation of rigid-rod polyamides and polyimides. The polymers were characterized by inherent viscosity, elemental

  3. Studies on Molecular Recongnition of (a)-Cyclodextrin with Diphenyl compounds

    Institute of Scientific and Technical Information of China (English)

    ZHANG You-ming; YAO Hong; WEI Tai-bao

    2004-01-01

    The cyclodextrins(CDs) are a class of cyclic oligosaccharides made up of six(a), seven(a)or more [a-(1,4)-linked] D-glucopyranose units, and shaped like truncated cones with primary and secondary hydroxyl groups crowning the narrower rim and wider rim respectively. As they have a hydrophobic cavity of appropriate dimension, they can bind with various guest moleculars, such as hydrocarbon, cyclohexane, aromatic compounds, to form inclusion complexes. The cyclodextins inclusion complexation has been considered an ideal model mimicking the enzyme-substrate interaction and a lot of effect has been devoted to it. In this paper, we report our investigation on the inclusion complexation behavior of a-cyclodextrin(a-CD) with diphenyl compounds in order to further explore the molecular recongnition mechanism of 2:1 inclusion complexation of a-CD with aromatic compounds.Figure 1: Possible structures of the inclusion compounds.The inclusion complexation behavior of a-CD with sym-diphenyl-urea, sym-diphenyl-thiourea and diphenyl kotone as respective guest moleclars was studied by ultraviolet spectrometric titrations.The absorption spectral changes observed for the compounds in the absence and presence of a-CD are used to draw the corresponding Benesi-Hildebrand plots and caculate the complex stability constant value (Ks) for the inclusion compounds.The 2:1 inclusion complexations show higher binding constants by cooperative binding of one guest molecular in the closely two hydrophobic cyclodextrin cavites as compared with 1:1 inclusion complexations.The highest value observed for sym-diphenyl-urea could be due to the formation of a hydrogen bond between the carbonyl group and the hydrogen in the hydroxyl group of CD and this is not possible with sym-tiphenyl-thiourea. The lowest value observed for diphenyl kotone indicate the hydrophobic interaction is one of the binding force of cyclodextrin inclusion complex.

  4. Studies on the interactions of 2,5-diphenyl 1,3,4-oxadiazole and 2,5-diphenyl 1,3-oxazole with β-cyclodextrin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Interactions of 2,5-diphenyl 1,3,4-oxadiazole (PPD) and 2,5-diphenyl 1,3-oxazole (PPO) with β-cyclodextrin (β-CD) are studied by 1H-NMR and steady-state fluorescence measurements, and the stoichiometries and the association constants are estimated. It is found that the hydrophobic interaction is the main driving force for the formation of inclusion complexes of PPD and PPO with β-CD. In the presence of aliphatic alcohols (from 1-propanol to 1-pentanol), PPD and PPO transfer from the CD cavity to the aqueous phase. Quenching experiments of PPD and PPO by iodide further prove the above conclusions. The results suggest that stereo effect is the crucial factor to the inexistence of nanotube in PPD (or PPO)-β-CD systems.

  5. The active-bridge oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Wessendorf, K.O.

    1998-07-01

    This paper describes the Active-Bridge Oscillator (ABO), a new concept in high-stability oscillator design. The ABO is ab ridge-type oscillator design that is easly to design and overcomes many of the operational and design difficulties associated with standard bridge oscillator designs. The ABO will oscillate with a very stable output amplitude over a wide range of operating conditions without the use of an automatic-level-control (ALC). A standard bridge oscillator design requires an ALC to maintain the desired amplitude of oscillation. for this and other reasons, bridge oscilaltors are not used in mainstream designs. Bridge oscillators are generally relegated to relatively low-volume, high-performance applications. The Colpitts and Pierce designs are the most popular oscillators but are typically less stable than a bridge-type oscillator.

  6. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  7. Synthesis of mono-fluorinated functionalized cyclopropanes and aziridines using the α-fluorovinyl diphenyl sulfonium salt.

    Science.gov (United States)

    Hirotaki, Kensuke; Takehiro, Yui; Kamaishi, Ryo; Yamada, Yasunori; Hanamoto, Takeshi

    2013-09-18

    The α-fluorovinyl diphenyl sulfonium salt 1 is attractive due to its high potential for the synthesis of mono-fluorinated cyclopropanes and aziridines as useful three-membered rings. The synthetically useful salt 1 is readily prepared from α-fluorovinyl phenyl sulfide and diphenyl iodonium salt in one step.

  8. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...... decisive for choosing the form of trusses, arches and cable-stayed bridges are outlined, and several examples show bridges designed without giving priority to the structural aspects....

  9. Morphological aspects of myocardial bridges.

    Science.gov (United States)

    Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

    2013-11-01

    Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64 ± 9.03 mm and the mean thickness was 1.23 ± 1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

  10. Modular FRP Composite Bridge Deck

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The bridge infrastructure of the United States is in constant need of repair and rehabilitation. It is reported that 43% of the bridges in the USA have been identified as being structurally deficient or functionally obsolete due to corrosion. SuperdeckTM, a non-corrosive fiber reinforced polymer (FRP) composite bridge deck. The Deck is designed and engineered into a lightweight, strong and rigid structure that will not corrode. The deck sections, composed of hexagon and double-trapezoid profi...

  11. Bridging Literature and Linguistics

    Directory of Open Access Journals (Sweden)

    Abdul Wahab

    2002-01-01

    Full Text Available Abstract: Two majors linguistics and literature in the schools of letters both in the state and private universities throughout Indonesia are commonly separated sharply. Courses of literature in the Department of Linguistics are offered minimally, such that the students of linguistics are not given a conducive atmosphere to express their literary appreciation. Likewise, courses of linguistics in the Department of Literature are very restricted, so that the students of literature are unable to analyze literary works from the points of linguistic view. This paper tries to bridge linguistics and literature. The attempt to bridge linguistics and literature is based on three postulates: (I literature consists of linguistic objects designed with an artistic end, (2 linguistic objects are formal objects, and (3 a formal account of linguistic object designed with an artistic end approximates a formal account of that artistic design. Two major directions in the approaches and emphases will be presented in the paper exogenous and endogenous. Exogenous approach tries to search for adequate description of (1 poetic language as contrasted with ordinary language, (2 language of a particular author contrasted with that of other authors, and (3 a particular literary work contrasted with other works of the same author. This part touches upon three areas of exogenous approach isolation, description, and characterization. Endogenous, on the hand, is based upon an assumption that a writer exhibits, probably without realizing it, certain systematic preferences for particular aspects of linguistic patterns. Planning a bridge between linguistics and literature is by no means without problems. Therefore, this paper also presents some possible solutions.

  12. Bridging Literature and Linguistics

    Directory of Open Access Journals (Sweden)

    Abdul Wahab

    2003-01-01

    Full Text Available Two majors linguistics and literature in the schools of letters both in the state and private universities throughout Indonesia are commonly separated sharply. Courses of literature in the Department of Linguistics are offered minimally, such that the students of linguistics are not given a conducive atmosphere to express their literary appreciation. Likewise, courses of linguistics in the Department of Literature are very restricted, so that the students of literature are unable to analyze literary works from the points of linguistic view. This paper tries to bridge linguistics and literature. The attempt to bridge linguistics and literature is based on three postulates: (1 literature consists of linguistic objects designed with an artistic end, (2 linguistic objects are formal objects, and (3 a formal account of linguistic object designed with an artistic end approximates a formal account of that artistic design. Two major directions in the approaches and emphases will be presented in the paper exogenous and endogenous. Exogenous approach tries to search for adequate description of (1 poetic language as contrasted with ordinary language, (2 language of a particular author contrasted with that of other authors, and (3 a particular literary work contrasted with other works of the same author. This part touches upon three areas of exogenous approach isolation, description, and characterization. Endogenous, on the hand, is based upon an assumption that a writer exhibits, probably without realizing it, certain systematic preferences for particular aspects of linguistic patterns. Planning a bridge between linguistics and literature is by no means without problems. Therefore, this paper also presents some possible solutions.

  13. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst...

  14. Bridging The Inferential Gap

    Science.gov (United States)

    Stewart, Walter F.; Shah, Nirav R.; Selna, Mark J.; Paulus, Ronald A.; Walker, James M.

    2009-01-01

    Most clinical decisions involve bridging the inferential gap: Clinicians are required to “fill in” where they lack knowledge or where no knowledge yet exists. In this context we consider how the inferential gap is a product, in part, of how knowledge is created, the limits to gaining access to such knowledge, and the variable ways in which knowledge is translated into decisions. We consider how electronic health records (EHRs) will help narrow this gap by accelerating the creation of evidence relevant to everyday practice needs and facilitating real-time use of knowledge in practice. PMID:17259202

  15. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even if the wi......With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...

  16. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  17. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of acaricides against ticks (Ixodidae) on ruminants.

    Science.gov (United States)

    Holdsworth, P A; Kemp, D; Green, P; Peter, R J; De Bruin, C; Jonsson, N N; Letonja, T; Rehbein, S; Vercruysse, J

    2006-02-28

    These guidelines have been prepared to assist in the planning, conduct and interpretation of studies for the assessment of the efficacy of acaricides (excluding vaccines and other bio-control agents) against single and multi-host ticks (Ixodidae) on ruminants. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping and result interpretation. The use of pen facilities is advocated for dose determination and confirmation studies for defining therapeutic and persistent efficacy. A minimum of two studies per tick species for which claims are sought is recommended for each dose determination and dose confirmation investigation. If dose confirmation studies demonstrate greater than 95% efficacy the sponsor may proceed to field studies, where a minimum of two studies per geographical location is preferred to confirm the therapeutic and persistent efficacy under field conditions. If dose confirmation studies demonstrate less than 95% efficacy then longer-term field studies can be conducted over two tick seasons with a minimum of two studies per geographical location. These studies can incorporate other control methods such as tick vaccines, to demonstrate stable long-term tick management. Specific advice is also given on conducting studies with paralysis ticks. These guidelines are also intended to assist investigators on how to conduct specific experiments, to provide specific information for registration authorities involved in the decision-making process, to assist in the approval and registration of new acaricides, and to facilitate the worldwide adoption of standard procedures.

  18. Susceptibility of geographically isolated populations of the Tomato red spider mite (Tetranychus evansi Baker & Pritchard to commonly used acaricides on tomato crops in Kenya

    Directory of Open Access Journals (Sweden)

    F. J. Toroitich

    2014-04-01

    Full Text Available Farmers in Kenya continue to raise concerns of difficulty in managing Tetranychus evansi, the most widespread pest species of tomato applying the most commonly used acaricides. This invasive pest species is not only found in Kenya, but in Eastern and Southern Africa, as well as parts of Europe and Asia. In the current study, populations of T. evansi were collected from farms in the four major tomato-growing areas of Kenya (Loitoktok, Kibwezi, Athi-River and Subukia and their susceptibility compared to a laboratory culture (ICIPE that had been maintained for three years without exposure to acaricides. Susceptibility of T. evansi eggs and adults (contact and residual to Brigade (bifenthrin, Dimethoate (dimethoate, Karate (lambdacyhalothrin, Kelthane (dicofol, Omite (propargite and Polytrin (profenofos+ cypermethrin was tested in the laboratory using respective manufacturer’s recommended concentrations. Dimethoate resulted in variable ovicidal mortality while Kelthane, Brigade, Karate, Omite and Polytrin had high mortality across all populations. Similarly, adult contact and residual mortality was lower than that of the other chemicals when exposed to Dimethoate regardless of the location. Furthermore, it also had no residual effect on the mites from ICIPE and Kibwezi. On the other hand, Kelthane was most lethal against the mites from all locations followed by Brigade and Polytrin in that order. Omite caused significantly lower mortality on mites from Subukia while Karate produced variable effects on mites from Kibwezi, Loitoktok and Subukia. The implications of these findings are further discussed.

  19. The preparation of neem oil microemulsion (Azadirachta indica) and the comparison of acaricidal time between neem oil microemulsion and other formulations in vitro.

    Science.gov (United States)

    Xu, Jiao; Fan, Qiao-Jia; Yin, Zhong-Qiong; Li, Xu-Ting; Du, Yong-Hua; Jia, Ren-Yong; Wang, Kai-Yu; Lv, Cheng; Ye, Gang; Geng, Yi; Su, Gang; Zhao, Ling; Hu, Ting-Xiu; Shi, Fei; Zhang, Li; Wu, Chang-Long; Tao, Cui; Zhang, Ya-Xue; Shi, Dong-Xia

    2010-05-11

    The preparation of neem oil microemulsion and its acaricidal activity in vitro was developed in this study. In these systems, the mixture of Tween-80 and the sodium dodecyl benzene sulfonate (SDBS) (4:1, by weight) was used as compound surfactant; the mixture of compound surfactant and hexyl alcohol (4:1, by weight) was used as emulsifier system; the mixture of neem oil, emulsifier system and water (1:3.5:5.5, by weight) was used as neem oil microemulsion. All the mixtures were stired in 800 rpm for 15 min at 40 degrees C. The acaricidal activity was measured by the speed of kill. The whole lethal time value of 10% neem oil microemulsion was 192.50 min against Sarcoptes scabiei var. cuniculi larvae in vitro. The median lethal time value was 81.7463 min with the toxicity regression equations of Y=-6.0269+3.1514X. These results demonstrated that neem oil microemulsion was effective against Sarcoptes scabie var. cuniculi larvae in vitro. (c) 2010. Published by Elsevier B.V. All rights reserved.

  20. Acaricidal effect and chemical composition of essential oils extracted from Cuminum cyminum, Pimenta dioica and Ocimum basilicum against the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

    Science.gov (United States)

    Martinez-Velazquez, Moises; Castillo-Herrera, Gustavo Adolfo; Rosario-Cruz, Rodrigo; Flores-Fernandez, Jose Miguel; Lopez-Ramirez, Julisa; Hernandez-Gutierrez, Rodolfo; Lugo-Cervantes, Eugenia del Carmen

    2011-02-01

    Acaricidal activity of essential oils extracted from cumin seeds (Cuminum cyminum), allspice berries (Pimenta dioica) and basil leaves (Ocimum basilicum) were tested on 10-day-old Rhipicephalus (Boophilus) microplus tick larvae using the LPT. Two-fold dilutions of the three essential oils were tested from a starting dilution of 20% down to 1.25%. Results showed a high toxicological effect for cumin, producing 100% mortality in all tested concentrations on R. microplus larvae. Similarly, allspice essential oil produced 100% mortality at all concentrations with the exception of a dramatic decrease at 1.25% concentration. Conversely, basil essential oil was not shown to be toxic against R. microplus larvae. The most common compounds detected by gas chromatography-mass spectrometry were as follows: cumin: cuminaldehyde (22.03%), γ-terpinene (15.69%) and 2-caren-10-al (12.89%); allspice: methyl eugenol (62.7%) and eugenol (8.3%); basil: linalool (30.61%) and estragole (20.04%). Results clearly indicate that C. cyminum and P. dioica essential oils can be used as an effective alternative for R. microplus tick control, and there is a high probability they can be used for other ticks affecting cattle in Mexico and throughout the world, thereby reducing the necessity for traditional and unfriendly synthetic acaricides.

  1. In Vitro Detection of Acaricidal Resistance Status of Rhipicephalus (Boophilus microplus against Commercial Preparation of Deltamethrin, Flumethrin, and Fipronil from North Gujarat, India

    Directory of Open Access Journals (Sweden)

    K. P. Shyma

    2015-01-01

    Full Text Available Rhipicephalus (Boophilus microplus is the most common tick species in India infesting cattle and buffaloes and causing significant economic losses to dairy and leather industries by adversely affecting the milk production and quality of hides. A study to evaluate the acaricide resistance status of Rhipicephalus (Boophilus microplus to deltamethrin, flumethrin, and fipronil was conducted on the samples collected from organized and unorganized farms of North Gujarat state, where treatment failures were reported frequently. Adult Immersion Test (AIT and Larval Packet Test (LPT were conducted using field strain for determination of 50 and 95% lethal concentration of deltamethrin, flumethrin, and fipronil. Results obtained by the Adult Immersion Test showed low grade resistance (level I, RF > 5 has been developed against both deltamethrin and fipronil. However, deltamethrin by performing Larval Packet Test showed moderate grade resistance (level II, RF > 25. Larval packet performed by flumethrin also revealed low grade resistance, level I. The data on field status of acaricide resistance from the area with diversified animal genetic resources will be helpful to adopt suitable strategy to overcome the process of development of resistance in ticks.

  2. In Vitro Detection of Acaricidal Resistance Status of Rhipicephalus (Boophilus) microplus against Commercial Preparation of Deltamethrin, Flumethrin, and Fipronil from North Gujarat, India

    Science.gov (United States)

    Shyma, K. P.; Gupta, Jay Prakash; Singh, Veer; Patel, K. K.

    2015-01-01

    Rhipicephalus (Boophilus) microplus is the most common tick species in India infesting cattle and buffaloes and causing significant economic losses to dairy and leather industries by adversely affecting the milk production and quality of hides. A study to evaluate the acaricide resistance status of Rhipicephalus (Boophilus) microplus to deltamethrin, flumethrin, and fipronil was conducted on the samples collected from organized and unorganized farms of North Gujarat state, where treatment failures were reported frequently. Adult Immersion Test (AIT) and Larval Packet Test (LPT) were conducted using field strain for determination of 50 and 95% lethal concentration of deltamethrin, flumethrin, and fipronil. Results obtained by the Adult Immersion Test showed low grade resistance (level I, RF > 5) has been developed against both deltamethrin and fipronil. However, deltamethrin by performing Larval Packet Test showed moderate grade resistance (level II, RF > 25). Larval packet performed by flumethrin also revealed low grade resistance, level I. The data on field status of acaricide resistance from the area with diversified animal genetic resources will be helpful to adopt suitable strategy to overcome the process of development of resistance in ticks. PMID:26788362

  3. The first assessment of the stress inducible defense of Leucaena leucocephala with acaricidal potential effect against Rhipicephalus (Boophilus microplus (Acari: Ixodidae

    Directory of Open Access Journals (Sweden)

    Lêdia Feitosa Wanderley

    Full Text Available Abstract Plants respond to wounding caused by mechanical stress or herbivory by synthesizing defense proteins. There are no studies reporting the action of induced plant proteins against ticks. The aim of this study was to investigate the effect of mechanically wounded Leucaena leucocephala leaves against Rhipicephalus (Boophilus microplus. Initially, we carried out time course experiments to evaluate the impact of mechanical wounding on the protein content and the peroxidase, catalase and protease inhibitor activities in L. leucocephala. We then evaluated the acaricidal activity on R. (B. microplus from protein extract collected from L. leucocephala after mechanical wounding. L. leucocephala leaves were artificially wounded, and after 6, 12, 24 and 48h, the leaves were collected for protein extraction. Quantitative and qualitative analyses of the proteins were performed. The protein content and peroxidase and protease activities increased 12h after wounding, and the acaricidal activity of this protein extract was evaluated using engorged R. (B. microplus females. The protein extract obtained after wounding reduced egg production (8.5% compared to those without wounding. Furthermore, the extract reduced egg hatching by 47.7% and showed an overall efficacy of 56.3% at 0.1 mgP/mL of the protein. We demonstrated that L. leucocephala defensive proteins could be effective against R. (B. microplus.

  4. The relative contribution of target-site mutations in complex acaricide resistant phenotypes as assessed by marker assisted backcrossing in Tetranychus urticae.

    Science.gov (United States)

    Riga, Maria; Bajda, Sabina; Themistokleous, Christos; Papadaki, Stavrini; Palzewicz, Maria; Dermauw, Wannes; Vontas, John; Leeuwen, Thomas Van

    2017-08-23

    The mechanisms underlying insecticide and acaricide resistance in insects and mites are often complex, including additive effects of target-site insensitivity, increased metabolism and transport. The extent to which target-site resistance mutations contribute to the resistance phenotype is, however, not well studied. Here, we used marker-assisted backcrossing to create 30 congenic lines carrying nine mutations (alone, or in combination in a few cases) associated with resistance to avermectins, pyrethroids, mite growth inhibitors and mitochondrial complex III inhibitors (QoI) in a polyphagous arthropod pest, the spider mite Tetranychus urticae. Toxicity tests revealed that mutations in the voltage-gated sodium channel, chitin synthase 1 and cytochrome b confer high levels of resistance and, when fixed in a population, these mutations alone can result in field failure of acaricide treatment. In contrast, although we confirmed the implication of mutations in glutamate-gated chloride channels in abamectin and milbemectin insensitivity, these mutations do not lead to the high resistance levels that are often reported in abamectin resistant strains of T. urticae. Overall, this study functionally validates reported target-site resistance mutations in T. urticae, by uncoupling them from additional mechanisms, allowing to finally investigate the strength of the conferred phenotype in vivo.

  5. Toxicidade de acaricidas a ovos e adultos de Ceraeochrysa cubana (Hagen, 1861 (Neuroptera: Chrysopidae Toxicity of acaricides to eggs and adults of Ceraeochrysa cubana (Hagen, 1861 (Neuroptera: Chrysopidae

    Directory of Open Access Journals (Sweden)

    Geraldo Andrade Carvalho

    2011-02-01

    Full Text Available Objetivou-se, neste trabalho, avaliar o efeito de treze acaricidas sobre ovos e adultos de Ceraeochrysa cubana (Hagen, 1861. Os acaricidas foram pulverizados por meio de torre de Potter, nas concentrações recomendadas para o controle de ácaros na cultura dos citros. Os ensaios foram conduzidos sob condições controladas de 25 ± 2º C, umidade relativa de 70 ± 10% e fotofase de 12 horas. Os acaricidas não foram tóxicos ao predador em sua fase de ovo. Em relação aos adultos, o carbosulfan e o triazophos foram altamente tóxicos (100% de mortalidade, enquanto que os piretróides bifenthrin e fenpropathrin causaram mortalidade aproximadamente de 60%. Os acaricidas dicofol, bromopropylate, tetradifon, clofentezine, abamectin, hexythiazox, cyhexatin e óxido de fenbutatin não provocaram mortalidade dos adultos de C. cubana. Flufenoxuron inibiu a capacidade de oviposição e provocou a inviabilização dos ovos. Baseando-se na escala da IOBC, os acaricidas carbosulfan, triazophos e flufenoxuron foram enquadrados na classe 4 = nocivos; bifenthrin e fenpropathrin na classe 2 = levemente nocivos, e dicofol, bromopropylate, tetradifon, clofentezine, abamectin, hexythiazox, cyhexatin e óxido de fenbutatin na classe 1 = inócuos a C. cubana. Os compostos enquadrados na classe 1 podem ser recomendados em programas de manejo integrado de pragas de citros objetivando a integração entre os métodos químico e biológico por meio dessa espécie de predador.The objective of this work was to evaluate the effects of thirteen acaricides on eggs and adults of the lacewing Ceraeochrysa cubana (Hagen, 1861. The acaricides were sprayed using a Potter's tower at the rate recommended for mite control in citrus orchard. The trials were performed in climatic chamber at 25 ± 2º C, 70 ± 10% RH and photophase of 12 hours. The egg stage showed high tolerance to the tested acaricides. Carbosulfan and triazophos caused 100% adult mortality, whereas bifenthrin and

  6. Elevated Serum Polybrominated Diphenyl Ethers and Alteration of Thyroid Hormones in Children from Guiyu, China

    NARCIS (Netherlands)

    Xu, Xijin; Liu, Junxiao; Zeng, Xiang; Lu, Fangfang; Chen, Aimin; Huo, Xia

    2014-01-01

    Informal electronic waste (e-waste) recycling results in serious environmental pollution of polybrominated diphenyl ethers (PBDEs) and heavy metals. This study explored whether there is an association between PBDEs, heavy metal and key growth-and development-related hormones in children from Guiyu,

  7. Pyridyl-1,2,4-triazole diphenyl boron complexes as efficient tuneable blue emitters

    NARCIS (Netherlands)

    Dijkstra, Peter; Angelone, Davide; Talnishnikh, Elena; Wörtche, Heinrich J.; Otten, Edwin; Browne, Wesley R.

    2014-01-01

    The detection of nuclear radiation necessitates the availability of new generations of tunable blue emitting fluorophores with high emission quantum yields. Here we show that pyridyl-1,2,4-triazole based diphenyl boron complexes can provide highly tuneable emission through facile modification of the

  8. Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

    Science.gov (United States)

    Jang, Hee Seung; Kim, Yubin

    2016-01-01

    Summary Chiral binaphthyl-modified squaramide-catalyzed enantioselective addition of diphenyl phosphonate to ketimines derived from isatins has been achieved. This method affords practical and efficient access to chiral 3-amino-3-phosphonyl-substituted oxindole derivatives in high yields with excellent enantioselectivities (up to 99% ee). PMID:27559405

  9. Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

    Directory of Open Access Journals (Sweden)

    Hee Seung Jang

    2016-07-01

    Full Text Available Chiral binaphthyl-modified squaramide-catalyzed enantioselective addition of diphenyl phosphonate to ketimines derived from isatins has been achieved. This method affords practical and efficient access to chiral 3-amino-3-phosphonyl-substituted oxindole derivatives in high yields with excellent enantioselectivities (up to 99% ee.

  10. Temporal Trends of Hexabromocyclododecane, Polybrominated Diphenyl Ethers and Polychlorinated Biphenyls in Ringed Seals from East Greenland

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Riget, Frank Farsø; Bossi, Rossana

    2011-01-01

    on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) have been extended with new data for 2006 and 2008. ΣPBDE in juvenile seals was the only parameter with a slight upward trend, however, dependent on the low 1986 concentration. Removing this data point resulted in a downward trend, which...... tolerable daily intake rates for seal blubber as traditional Arctic food items....

  11. Radical Quenching of 1,1-Diphenyl-2-picrylhydrazyl: A Spectrometric Determination of Antioxidant Behavior

    Science.gov (United States)

    Berger, John M.; Rana, Roshniben J.; Javeed, Hira; Javeed, Iqra; Schulien, Sandi L.

    2008-01-01

    Radical chemistry is a fundamental subject of undergraduate organic chemistry. While well described in organic textbooks, laboratory manuals rarely address this topic, focusing instead on syntheses using polar reactions. Herein, we describe a colorimetric assay using the persistent radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) to measure the…

  12. Phosgene free route to methyl diphenyl diisocynate (MDI): A technical and economical evaluation

    NARCIS (Netherlands)

    Berg, van den H.; Ham, van der A.G.J.; Gutierrez, H.; Odu, S.O.; Roelofs, T.; Weerdt, de J.

    2012-01-01

    The objective is to design an alternative production process for Methyl Diphenyl Diisocyanate (MDI) in which no toxic phosgene is used. The plant should use 4,4′-Methylenedianiline (MDA) as a raw material. Seven routes found in the open literature were investigated and compared on process conditions

  13. Development of an electrochemical immunoassay for the detection of polybrominated diphenyl ethers (PBDEs)

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are persistent environmental substances that were commonly used as fire retardants in a wide number of commercial products. Their low reactivity, high hydrophobicity and bioaccumulative properties cause their ubiquity in the air, water, food and lead to extensi...

  14. Exposure to polybrominated diphenyl ethers and male reproductive function in Greenland, Poland and Ukraine

    NARCIS (Netherlands)

    Toft, Gunnar; Lenters, Virissa; Vermeulen, Roel; Heederik, Dick; Thomsen, Cathrine; Becher, Georg; Giwercman, Aleksander; Bizzaro, Davide; Manicardi, Gian Carlo; Spano, Marcello; Rylander, Lars; Pedersen, Henning S.; Strucinski, Pawel; Zviezdai, Valentyna; Bonde, Jens Peter

    2014-01-01

    Animal and a few human studies suggest that polybrominated diphenyl ethers (PBDEs) may affect male reproductive function. The aim of the present study was to evaluate if male reproductive function was associated with serum level of PBDEs. We evaluated, in a cross-sectional study, the effects of envi

  15. Exposure to Polybrominated Diphenyl Ethers and Male Reproductive Function in Greenland, Poland and Ukraine

    DEFF Research Database (Denmark)

    Toft, Gunnar; Lenters, Virissa; Vermeulen, Roel

    2013-01-01

    Animal and a few human studies suggest that polybrominated diphenyl ethers (PBDEs) may affect male reproductive function. The aim of the present study was to evaluate if male reproductive function was associated with serum level of PBDEs. We evaluated, in a cross-sectional study, the effects of e...... of these compounds in fertile European or Arctic populations....

  16. Exposure to polybrominated diphenyl ethers and male reproductive function in Greenland, Poland and Ukraine

    NARCIS (Netherlands)

    Toft, Gunnar; Lenters, Virissa; Vermeulen, Roel; Heederik, Dick; Thomsen, Cathrine; Becher, Georg; Giwercman, Aleksander; Bizzaro, Davide; Manicardi, Gian Carlo; Spano, Marcello; Rylander, Lars; Pedersen, Henning S.; Strucinski, Pawel; Zviezdai, Valentyna; Bonde, Jens Peter

    2014-01-01

    Animal and a few human studies suggest that polybrominated diphenyl ethers (PBDEs) may affect male reproductive function. The aim of the present study was to evaluate if male reproductive function was associated with serum level of PBDEs. We evaluated, in a cross-sectional study, the effects of envi

  17. In vitro estrogenicity of polybrominated diphenyl ethers, hydroxylated PBDEs, and polybrominated bisphenol A compounds

    NARCIS (Netherlands)

    Meerts, I.A.T.M.; Letcher, R.J.; Hoving, S.; Marsh, G.; Bergman, A.; Lemmen, J.G.; Burg, van der B.; Brouwer, A.

    2001-01-01

    Polybrominated diphenyl ethers (PBDEs) are used in large quantities as additive flame retardants in plastics and textile materials. PBDEs are persistent compounds and have been detected in wildlife and in human adipose tissue and plasma samples. In this study, we investigated the (anti)estrogenic po

  18. Acaricidal activity against Tetranychus urticae and essential oil composition of four Croton species from Caatinga biome in northeastern Brazil.

    Science.gov (United States)

    Neves, Ilzenayde Araújo; da Camara, Claudio Augusto Gomes

    2011-06-01

    Volatile components of essential oils from the leaves and stems of Croton jacobinensis, C. rhamnifolius, C. muscicapa and C. micans, which are medicinal plants found in the Caatinga biome of northeastern Brazil, were analyzed using GC and GC/MS. The acaricidal activity of these oils against Tetranychus urticae was evaluated using the fumigation method. Oil yields from the Croton species ranged from 1.1 +/- 0.0 to 0.6 +/- 0.0%, w/w, for leaves and 0.7 +/- 0.0 to 0.1 +/- 0.0% for stems. Sesquiterpenoids were dominant in all oils, except the stem oil from C. rhamnifolius, which exhibited a high monoterpene content, and the leaf and stem oils from C. muscicapa, which were rich in phenylpropanoids. The major volatile components of the leaf and stem oils from C. jacobinensis were (Z)-alpha-atlantone (24.3 +/- 0.4%) and trans-isolongifolanone (22.8 +/- 0.5%), respectively. The most abundant constituents detected in C. rhamnifolius were alpha-cedrene epoxide (23.3 +/- 0.1%) and caryophyllene oxide (21.9 +/- 0.0%) in the leaf oil, and camphor (16.6 +/- 0.5%) and tricyclene (12.8 +/- 0.1%) in the stem oil. Foenicolin was the main compound identified in the leaf (50.6 +/- 0.2%) and stem (72.7 +/- 0.6%) oils of C. muscicapa, while alpha-bulnesene (32.9 +/- 0.2%) and guaiol (17.9 +/- 0.7%) were the principal components of C. micans oils. These oils exhibited a high degree of toxicity in the fumigation assay. The stem oils from C. jacobinensis and C. rhamnifolius exhibited high lethality rates, with LC50 values of 0.3 and 0.2 microL/L of air after 24 h, respectively. The results suggest the potential use of stem essential oil, especially from C. rhamnifolius and C. jacobinensis, for the integrated control of Tetranychus urticae.

  19. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  20. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2005-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  1. London Bridge Is Shaking Funny

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    Bridges generally don’t fall down without warning;they crack first. Searching for cracks is a tedious business,though, and bridge inspectors bave been known to miss them. Charles Farrar,a civil engineer at Los Alamos Na-

  2. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  3. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst......The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... groups, the sociology of work needs to develop a better understanding of the way in which linguistic diversity influences the formation of social capital, i.e. resources such as the trust and reciprocity inherent in social relations in such workplaces. Drawing on theories about intergroup contact...

  4. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2016-12-05

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  5. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  6. Torsional instability in suspension bridges: The Tacoma Narrows Bridge case

    Science.gov (United States)

    Arioli, Gianni; Gazzola, Filippo

    2017-01-01

    All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.

  7. Experiences in tick control by acaricide in the traditional cattle sector in Zambia and Burkina Faso: possible environmental and public health implications

    Directory of Open Access Journals (Sweden)

    Daniele De Meneghi

    2016-11-01

    Full Text Available Livestock, especially cattle, play a paramount role in agriculture production systems, particularly in poor countries throughout the world. Ticks and tick-borne diseases (TBDs have an important impact on livestock and agriculture production in Sub-Saharan Africa. The authors review the most common methods used for the control of ticks and TBDs. Special emphasis is given to the direct application of acaricides to the host animals. The possible environmental and public health adverse effects (i.e. risks for the workers, residues in the environment, and in food products of animal origin are mentioned. The authors present two case studies, describing different field experiences in controlling ticks in two African countries. In Zambia (Southern Africa, a strategic dipping regime was used to control Rhipicephalus appendiculatus ticks, vectors of theileriosis, a deadly disease affecting cattle in the traditional livestock sector in Southern Province. The dipping regime adopted allowed to reduce the tick challenge and cattle mortally rate, and at the same time, to employ less acaricide as compared to the intensive dipping used so far, without disrupting the building-up of enzootic stability. In Burkina Faso (West Africa, where dipping was never used for tick control, an acaricide footbath was employed as an alternative method to the traditional technique used locally (portable manual sprayers. This was developed from field observations on the invasion/attachment process of the Amblyomma variegatum ticks –vector of cowdriosis- on the animal hosts, leading to a control method aimed to kill ticks temporarily attached to the interdigital areas before their permanent attachment to the predilection sites. This innovative method has been overall accepted by the local farmers. It has the advantage of greatly reducing costs of treatments and has a minimal environmental impact, making footbath a sustainable and replicable method, adoptable also in other West

  8. Strategic applications of long-acting acaricides against Rhipicephalus (Boophilus) microplus in northwestern Argentina, with an analysis of tick distribution among cattle.

    Science.gov (United States)

    Nava, Santiago; Mangold, Atilio J; Canevari, José T; Guglielmone, Alberto A

    2015-03-15

    Strategic applications of long-acting acaricides for the control of Rhipicephalus (Boophilus) microplus in northwestern Argentina were evaluated for one year. In addition, tick distribution among cattle was analyzed to evaluate if partial selective treatment or culling the small proportion of most heavily infested animals were feasible options to control R. (B.) microplus. Two different treatments schemes based on two applications of fluazuron and one application of 3.15% ivermectin were performed. Treatments were made in late winter and spring so as to act on the small 1st spring generation of R. (B.) microplus, in order to preclude the rise of the larger autumn generation. The overall treatment effect was positively significant in both schemes. The number of ticks observed in the control group was significantly higher than in the treated groups on all post-treatment counts. Group 2 exhibited more than 80% of efficacy almost throughout the study period, whereas Group 1 exhibited an efficacy percentage higher than 80% in September, October, December, February, April and May, but not in November (73.4%), January (58.3%), March (45.2%) or June (53.4%). Absolute control was observed in Group 2 in the counts of September and October, and in Group 1 in the count of February. The control strategies evaluated in this work provide an acceptable control level with only three applications of acaricides; at the same time, they prevent the occurrence of the autumn peak of tick burdens, which is characteristic of R. (B.) microplus in northwestern Argentina. Tick distribution was markedly aggregated in all counts. Although ticks were not distributed evenly among calves, the individual composition of the most heavily infested group was not consistent throughout the study period. In addition, the level of aggregation varied with tick abundance. These results suggest that applying acaricides to a portion of the herd or culling the most infested individuals at a given moment of the

  9. National Bridge Inventory - National Geospatial Data Asset (NGDA) Bridges

    Data.gov (United States)

    Department of Transportation — The NBI (NTAD 2015) is a collection of information (database) describing the more than 610,000 of the Nation's bridges located on public roads, including Interstate...

  10. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration approach...

  11. AIRBORNE POLYBROMINATED DIPHENYL ETHERS IN A COMPUTER CLASSROOM OF COLLEGE IN TAIWAN

    Directory of Open Access Journals (Sweden)

    F. H. Chang ، C. R. Yang ، C. Y. Tsai ، W. C. Lin

    2009-04-01

    Full Text Available This study characterized the airborne exposure of students to thirty polybrominated diphenyl ether congeners inside and outside a computer classroom in a southern Taiwan college. Arithmetic mean values of total indoor and outdoor polybrominated diphenyl ether concentrations were 125.0 pg/m3 (89.8 to 203.9 pg/m3 and 110.3 pg/m3 (83.5 to 157.0 pg/m3, respectively. Total indoor polybrominated diphenyl ether concentrations were one order of magnitude lower than those detected in homes in Birmingham, United Kingdom and in Ottawa, Canada but were several times higher than those measured in the ambient air in Ottawa, Canada and from the Bohai Sea to the Arctic. The five highest indoor concentrations of polybrominated diphenyl ether congeners were decabromodiphenyl ether (23.0 pg/m3, 4,4’-dibromodiphenyl ether (15.9 pg/m3, 2,2’,3,4,4’,5,5’,6-octabromodiphenyl ether (10.6 pg/m3, 2,4-dibromodiphenyl ether (10.3 pg/m3 and 2,2’,3,4,4’,5’,6-heptabromodiphenyl ether (10.0 pg/m3. Although indoor and outdoor total polybrominated diphenyl ether concentrations did not significantly differ, the indoor concentrations of 2,4-dibromodiphenyl ether, 2,2’,4-tribromodiphenyl ether, 2,4,4’-tribromodiphenyl ether, 2,2’,4,5’-tetrabromodiphenyl ether and 2,3’,4’,6-tetrabromodiphenyl ether were significantly higher than their outdoor concentrations. This study suggests the following measures: 1 to increase the air exchange rate and open classroom doors and windows for several minutes before classes to reduce indoor PBDE concentrations; 2 to reduce polybrominated diphenyl ether emissions from new devices, it’s better to use computer-related products that meet the Restriction of Hazardous Substances Directive adopted by the European Union.

  12. Monoaminergic agents modulate antidepressant-like effect caused by diphenyl diselenide in rats.

    Science.gov (United States)

    Savegnago, Lucielli; Jesse, Cristiano R; Pinto, Larissa G; Rocha, Joao B T; Nogueira, Cristina W; Zeni, Gilson

    2007-08-15

    In this study, the antidepressant-like effect caused by diphenyl diselenide on rat forced swimming test (FST) was investigated. The involvement of the monoaminergic system in the antidepressant-like effect was also evaluated. Diphenyl diselenide (0.1-30 mg/kg), given by oral route (p.o.), 30 min earlier, reduced the immobility time in the FST, without accompanying changes in ambulation when assessed in an open field. The anti-immobility effect of diphenyl diselenide (1 mg/kg, p.o.) on the FST was prevented by pretreatment of rats with p-chlorophenylalanine methyl ester (PCPA; 100 mg/kg, i.p., an inhibitor of serotonin synthesis, given once a day, for 3 consecutive days), WAY100635 (0.1 mg/kg, s.c., a selective 5-HT(1A) receptor antagonist), ketanserin (1 mg/kg, i.p., a 5-HT(2A)/(2C) receptor antagonist), ondasentron (1 mg/kg, i.p., a 5-HT(3) receptor antagonist), haloperidol (1 mg/kg, i.p., a D(1), D(2) and D(3) receptor antagonist), SCH233390 (0.05 mg/kg, s.c., a D(1) receptor antagonist), sulpiride (50 mg/kg, i.p., a D(2) receptor antagonist), prazosin (1 mg/kg, i.p., an alpha(1)-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an alpha(2)-adrenoceptor antagonist). However, the anti-immobility effect caused by diphenyl diselenide (1 mg/kg, p.o.) on the FST was not affected by pretreatment with propanolol (2 mg/kg, i.p., a beta-adrenoceptor antagonist). Furthermore, monoamine oxidase (MAO) activity was inhibited (39%) in the animals treated with diphenyl diselenide (30 mg/kg, p.o.) when compared to the control group. Taken together these data demonstrated that the antidepressant-like effect caused by diphenyl diselenide seems to be mediated by involvement of the central monoaminergic system.

  13. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  14. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  15. 6种杀螨剂对石榴小爪螨的毒力测定%Evaluation of Toxicity of Six Acaricides on the Avocado Brown Mite

    Institute of Scientific and Technical Information of China (English)

    赵利敏; 高旭刚; 罗纪虎

    2012-01-01

    [目的]石榴小爪螨近年在陕西汉中危害园林建筑植物樟树,亟需筛选有效药剂进行防治.[方法]利用6种杀螨剂、按药膜法对其雌螨实施毒力测定,分析急性触杀效果.[结果]各供试杀螨剂致死浓度对数值与雌螨校正死亡率机率值相关显著,毒力回归式斜率为1.59~3.70,LC50值为0.3~4540.6 μg a.i./L,而LC95值为1.0~48981 μg a.i./L.毒力强弱次序为15%苯丁·哒螨灵乳油>15%哒螨灵乳油>2%阿维菌素乳油>30%哒螨灵可湿性粉剂>25%三唑锡可湿性粉剂.以三唑锡LC50值为标准估算,苯丁·哒螨灵相对毒力指数为12986倍,其他杀螨剂位此极值间.[结论]供试杀螨剂都能以较低剂量杀死石榴小爪螨实验种群;其LC95值的10倍浓度可用作户外防治此螨的参考剂量.%[Aims] The avocado brown mite, Oligonychus punicae (Acariformes: Tetranychidae) have been injuring camphor trees, a horticultural and forest architectural plant, in Hanzhong, Shaanxi, China, in recent years, and they are needed to be controlled. [Methods] Under a procedure of residual film method, six acaricides were assayed to evaluate their acute contact toxicity on female mites. [Results] The analyses indicated that log lethal concentrations of each acaricide were correlated significantly to probits of corrected female mortalities; the slopes of the regression equations for toxicity ranged from 1.59 to 3.70; LC50, was 0.3-4540.6 μg a.i./L, and LC95, 1.0-48981 μg a.i./L. Arranged in toxicity from strong to weak, the rank was: mixture of fenbutatin oxide o pyridaben 15% EOpyridaben 15% EOavermectins 2% EC>pyridaben 30% WP >azocyclotin 25% WP. Estimated on LC50 of azocyclotin, the index of relative toxicity of fenbutatin oxide - pyridaben was 12986 folds and that of the other acaricides was between the extremes. [Conclusions] The acaricides tested are all able to cause experimental populations of O. punicae to death in much lower doses; a 10-fold

  16. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

    The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than six thousand scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a tr...

  17. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  18. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

    Public participation in bridge building was promoted by un habitat in the village of Mankrong. The neighbouring village did not participate in the construction of their bridge. The first flooding washed the second bridge down while the "participative bridge" stood up....

  19. PERINATAL EXPOSURE TO A POLYBROMINATED DIPHENYL ETHER MIXTURE (DE-71) DISRUPTS THYROID HORMONES BUT NOT NEUROBEHAVIORAL DEVELOPMENT.

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs), produced commercially as mixtures, are used as flame-retardants for numerous consumer products. Because of their lipophilicity and persistence, PBDEs have become ubiquitous environmental contaminants. Previous work in our lab has demonstra...

  20. Altered cardiovascular reactivity and osmoregulation during hyperosmotic stress in adult rats developmentally exposed to polybrominated diphenyl ethers (PBDEs)

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) and the structurally similar chemicals polychlorinated biphenyls (PCBs) disrupt the function of multiple endocrine systems. PCBs and PBDEs disrupt the secretion of vasopressin (VP) from the hypothalamus during osmotic activation. Since the p...

  1. Polybrominated diphenyl ether serum concentrations in a Californian population of children, their parents, and older adults: an exposure assessment study

    Science.gov (United States)

    BackgroundPolybrominated diphenyl ethers (PBDEs) are used as flame retardants in many household items. Given concerns over their potential adverse health effects, we identified predictors and evaluated temporal changes of PBDE serum concentrations.MethodsPBDE serum concentrations...

  2. Suscetibilidade de Rhipicephalus (Boophilus microplus a carrapaticidas em Mato Grosso do Sul, Brasil Susceptibility of Rhipicephalus (Boophilus microplus to acaricides in Mato Grosso do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Alberto Gomes

    2011-08-01

    demonstrada aos distintos produtos testados sugere que a resistência do carrapato a diferentes classes esteja amplamente disseminada no Estado, motivo pelo qual recomenda-se a realização rotineira de testes de suscetibilidade antes da seleção e aplicação de produtos acaricidas para controle do carrapato.The cattle tick, Rhipicephalus (Boophilus microplus, is one of the most important ectoparasites of bovines, requiring adoption of control measures mainly in Bos taurus herds and its crossbreeds. Its control has becoming increasingly difficult due to selection of resistant populations by commercial products. This study aimed to know the status of cattle tick resistance to acaricides in the state of Mato Grosso do Sul. From October 2003 to October 2006 acaricide bioassays were conducted on cattle ticks from eleven of the most important livestock regions of the state. Adult immersion tests using regular commercial products according to label recommendations were followed by the evaluation of biological parameters. Twelve acaricide products containing one or more of seven active ingredients, from three chemical classes: amidine (amitraz, synthetic pyrethroid (cypermethrin, and organophosphates (chlorfenvinphos, chlorpyriphos, diazinon, dichlorvos, and ethion were tested. Low tick susceptibility was observed in all ranches, with several populations showing virtually no susceptibility to one or more products. Despite the great variation of susceptibility shown by the populations to each acaricide, a gradient of efficacy of these products was observed. Regardless of the acaricide class, the average efficacy of products containing a single active ingredient (19.94%-64.27% was generally lower than that showed by the mixtures, pyrethroid-organophosphate (46.38%-82.68% and between organophosphates (85.28%-97.68%. The mixture containing pyrethroid + OF + synergist + repellent (cypermethrin + chlorpyrifos + citronellal + piperonyl butoxide showed 100% efficacy, although it was

  3. N-(Diphenyl-vinyl-idene)-2,6-diisopropyl-aniline.

    Science.gov (United States)

    Imhof, Wolfgang

    2008-12-06

    The title compound, C(26)H(27)N, was prepared by the elimination of water from N-(2,6-diisopropyl-phen-yl)-2,2-diphenyl-acetamide. The angle at the central C atom of the cumulene measures 172.5 (4)°. Mol-ecules are connected into infinite chains by inter-molecular C-H⋯N inter-actions.

  4. Tri-n-butylphosphine Mediated Ring-Opening Reactions of Aziridines or Epoxides with Diphenyl Diselenide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wan-Xuan; YE Kang; RUAN Shan; CHEN Zu-Xing; XIA Qing-Hua

    2007-01-01

    Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of (n-Bu)3P, respectively, giving β-amino-or β-hydroxy selenides in moderate to excellent yields under mild conditions. In the reactions the (n-Bu)3P might act as a reductant though it was a nucleophilic catalyst in other similar ring-opening reactions.

  5. Linear free energy relationship in reactions between diphenyl amine and benzyl bromides

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2006-05-01

    Rate of reaction between benzyl bromide and diphenyl amine is retarded by electron-donating groups and enhanced by electron-withdrawing groups present on the benzene ring of the substrate. Hammett's reaction constant of the reaction decreases with increase in temperature according to the equation, \\rho = -11.92 + 3.54/ T. Minimal structural effects observed are attributed to the fact that the isokinetic temperature of the reaction is close to the reaction temperature.

  6. Polybrominated Diphenyl Ether Exposure and Thyroid Function Tests in North American Adults

    OpenAIRE

    Makey, Colleen M.; McClean, Michael D.; Braverman, Lewis E.; Pearce, Elizabeth N.; He, Xue-Mei; Sjödin, Andreas; Weinberg, Janice M; Webster, Thomas F

    2015-01-01

    Background: Polybrominated diphenyl ethers (PBDEs) are flame-retardant chemicals that are added to many consumer products. Multiple animal studies have shown PBDEs to be thyroid hormone (TH) disruptors. Epidemiologic evidence of PBDE exposure associated with TH disruption has been inconclusive. Objectives: We used repeated measures to estimate associations between serum PBDE concentrations and THs in a North American adult cohort. Methods: From 2010 to 2011, we collected ≤ 3 serum samples at ...

  7. Temporal Variability of Polybrominated Diphenyl Ether (PBDE) Serum Concentrations over One Year

    OpenAIRE

    Makey, Colleen M.; McClean, Michael D.; Sjödin, Andreas; Weinberg, Janice; Carignan, Courtney C.; Webster, Thomas F

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are flame retardant chemicals used in consumer products. They are common contaminants in human serum and associated with adverse health effects. Our objectives were to characterize PBDE serum concentrations in a New England cohort and assess temporal variability of this exposure biomarker over a one-year period. We collected three repeated measurements at six-month intervals from 52 office workers from the greater Boston (MA, United States) area from 201...

  8. In vitro estrogenicity of polybrominated diphenyl ethers, hydroxylated PBDEs, and polibrominated bisphenol A compounds

    OpenAIRE

    Meerts, I.A.T.M.; Letcher, R J; Hoving, S; Marsh, G.; Bergman, A; Lemmen, J. G.; Burg, van der, R.; Brouwer, A.

    2001-01-01

    Polybrominated diphenyl ethers (PBDEs) are used in large quantities as additive flame retardants in plastics and textile materials. PBDEs are persistent compounds and have been detected in wildlife and in human adipose tissue and plasma samples. In this study, we investigated the (anti)estrogenic potencies of several PBDE congeners, three hydroxylated PBDEs (HO-PBDEs), and differently brominated bisphenol A compounds in three different cell line assays based on estrogen receptor (ER)-dependen...

  9. In vitro estrogenicity of polybrominated diphenyl ethers, hydroxylated PDBEs, and polybrominated bisphenol A compounds.

    OpenAIRE

    Meerts, I A; Letcher, R J; Hoving, S; Marsh, G.; Bergman, A; Lemmen, J. G.; Van der Burg, B.; Brouwer, A.

    2001-01-01

    Polybrominated diphenyl ethers (PBDEs) are used in large quantities as additive flame retardants in plastics and textile materials. PBDEs are persistent compounds and have been detected in wildlife and in human adipose tissue and plasma samples. In this study, we investigated the (anti)estrogenic potencies of several PBDE congeners, three hydroxylated PBDEs (HO-PBDEs), and differently brominated bisphenol A compounds in three different cell line assays based on estrogen receptor (ER)-dependen...

  10. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    Directory of Open Access Journals (Sweden)

    N. Maghamipour N. Safaei

    2007-06-01

    Full Text Available Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical unroofing of myocardial bridging. Patients had a myocardial bridge of at least 3 cm in length in the middle of LAD and with more than 70% compression during systole. Unroofing was performed with cardiopulmonary bypass in 16 and with off pump technique in 10 patients. In 6 patients repeat angiographies for control of myotomy were done. In one of them a nonsignificant 20% narrowing was seen. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation in 24 patients. Two patients had residual narrowing. With off pump technique, 1 patient had perforation of the right ventricle and 1 patient underwent reoperation because of incomplete unroofing during the first operation. None of the patients with cardiopulmonary bypass technique had residual chest pain or other complications. Surgical unroofing of myocardial bridging with the aid of cardiopulmonary bypass is a safe and easy procedure with low operative risk and with excellent functional results.

  11. Helix—Sense—Selective Polymerization of N,N—Diphenyl (Meth) acrylamide by Anionic Catalysts

    Institute of Scientific and Technical Information of China (English)

    HongXUE; YongAnXU; 等

    2002-01-01

    In this paper, the helix-sense-selective polymerization of N,N-diphenyl acrylamide (DPAA) and N,N-diphenyl methacrylamide (DPMAA) were studied with living helix prepolymer as anionic initiator, and the chiral optical properties of the obtained polymers were investigated too. It was shown that optically active polymers of DPAA and DPMAA could be obtained under the experimental condition, and exhibited the same screw sense as that of the prepolymer.

  12. Quantification of Hydroxylated Polybrominated Diphenyl Ethers (OH-BDEs), Triclosan, and Related Compounds in Freshwater and Coastal Systems

    OpenAIRE

    Jill F Kerrigan; Engstrom, Daniel R.; Donald Yee; Charles Sueper; Erickson, Paul R.; Matthew Grandbois; Kristopher McNeill; William A Arnold

    2015-01-01

    Hydroxylated polybrominated diphenyl ethers (OH-BDEs) are a new class of contaminants of emerging concern, but the relative roles of natural and anthropogenic sources remain uncertain. Polybrominated diphenyl ethers (PBDEs) are used as brominated flame retardants, and they are a potential source of OH-BDEs via oxidative transformations. OH-BDEs are also natural products in marine systems. In this study, OH-BDEs were measured in water and sediment of freshwater and coastal systems along with t...

  13. Enhanced diastereoselectivity via confinement: diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites.

    Science.gov (United States)

    Sivaguru, J; Sunoj, Raghavan B; Wada, Takehiko; Origane, Yumi; Inoue, Yoshihisa; Ramamurthy, V

    2004-08-20

    Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C1-C2 or C1-C3 bond. From the perspective of chiral induction, photoisomerization of cis-2,3-diphenyl-1-benzoylcyclopropane derivatives with chiral auxiliaries placed at the meta and para positions of the benzoyl group have been examined both in isotropic solution and within zeolites. Whereas in isotropic solution the chiral auxiliaries placed at the meta position exhibit very little influence during the conversion of triplet cis-2,3-diphenyl-1-benzoylcyclopropane derivatives, they have significant influence within zeolites. For example, alpha-methyl benzylamine placed at the meta position of the benzoyl group (via an amide bond) yields the trans isomer with a diastereoselectivity (de) of 71% within NaY zeolite, whereas in solution no de is obtained. The chiral induction process within zeolites depends on the nature of the alkali ion and on the presence of water. Results suggest that the chiral auxiliary is able to control the bond being cleaved (C1-C2 vs. C1-C3 bond) within a zeolite, but it is unable to do so in an isotropic solution.

  14. Broadband Microwave Spectroscopy as a Tool to Study Intermolecular Interactions in the Diphenyl Ether - Water System

    Science.gov (United States)

    Fatima, Mariyam; Perez, Cristobal; Schnell, Melanie

    2017-06-01

    Many biological processes, such as chemical recognition and protein folding, are mainly controlled by the interplay of hydrogen bonds and dispersive forces. This interplay also occurs between organic molecules and solvent water molecules. Broadband rotational spectroscopy studies of weakly bound complexes are able to accurately reveal the structures and internal dynamics of molecular clusters isolated in the gas phase. Amongst them, water clusters with organic molecules are of particular interest. In this work, we investigate the interplay between different types of weak intermolecular interactions and how it controls the preferred interaction sites of aromatic ethers, where dispersive interactions may play a significant role. We present our results on diphenyl ether (C_{12}H_{10}O, 1,1'-Oxydibenzene) complexed with up to three molecules of water. Diphenyl ether is a flexible molecule, and it offers two competing binding sites for water: the ether oxygen and the aromatic π system. In order to determine the structure of the diphenyl ether-water complexes, we targeted transitions in the 2-8 GHz range using broadband rotational spectroscopy. We identify two isomers with one water, one with two water, and one with three water molecules. Further analysis from isotopic substitution measurements provided accurate structural information. The preferred interactions, as well as the observed structural changes induced upon complexation, will be presented and discussed.

  15. Redundancy Evaluation of Fracture Critical Bridges

    OpenAIRE

    Bapat, Amey Vivek

    2014-01-01

    Cases of brittle fractures in major bridges prompted AASHTO to publish its first fracture control plan in 1978. It focused on material and fabrication standards, and required periodic 24-month hands-on inspection of bridges with fracture critical members. The practical result of this plan was to significantly increase the life cycle cost of these bridges, rendering them uneconomical. Apart from the Point Pleasant Bridge that failed in 1967, no other bridge has collapsed in the USA following a...

  16. Microbial degradation of 4-monobrominated diphenyl ether in an aerobic sludge and the DGGE analysis of diversity.

    Science.gov (United States)

    Chen, Chun-Yao; Wang, Chun-Kang; Shih, Yang-Hsin

    2010-07-01

    Polybrominated diphenyl ethers (PBDEs) were applied as flame retardant additives in polymers for many plastic and electronic products. Due to their ubiquitous distribution in the environment, potential toxicity to human and tendency for bioaccumulation, PBDEs have raised public safety concern. In this study we examined the degradation of 4-monobrominated diphenyl ether (4-BDE) in aerobic sludge, as a model for PBDE biodegradation. Degradation of 4-BDE was observed in aerobic sludge. Co-metabolism with toluene or diphenyl ether facilitated 4-BDE biodegradation in terms of kinetics and efficiency. Diphenyl ether seems to perform slightly better as an auxiliary carbon source than toluene in facilitating 4-BDE degradation. During the experiment we identified diphenyl ether by gas chromatography/mass spectrometry(GC/MS), which indicates that an anaerobic debromination has occurred. Bacterial community composition was monitored with denaturing gradient gel electrophoresis. The fragments enriched in 4-BDE-degrading aerobic sludge samples belong to presumably a novel anaerobic Clostridiales species distantly related to all known debrominating microbes. This suggests that 4-BDE biodegradation can occur in anaerobic micro-niche in an apparently aerobic environment, by a previously unknown bacterial species. These findings can provide better understandings of biodegradation of brominated diphenyl ethers and can facilitate the prediction of the fate of PBDEs in the environment.

  17. The Akashi Kaikyo Bridge and the Storebælt Bridge

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

  18. Weigh-in-motion and smart bridges

    Science.gov (United States)

    Lai, Leon L.

    1997-05-01

    The bridge Weigh-In-Motion (WIM) system uses bridge structures as weigh scales to measure axle and gross vehicle weights and vehicle configurations without stopping or detouring the vehicles. Because the system is mobile and is almost invisible to the truck drivers, it can be used to collect unbiased traffic data for transportation and loadometer study. The WIM + RESPONSE system, which is an expansion of the original WIM system, was developed to collect additional bridge response data and perform bridge structural evaluation. These additional bridge response data provide bridge engineers with information necessary for improving bridge design and evaluation procedures. Bridge health monitoring and damage detection may also be conducted with long term installation of the WIM + RESPONSE system. This paper discusses what has been achieved by the WIM + RESPONSE system and how the system can be further improved to enhance its functions in a smart bridge.

  19. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

    On folio 855 recto of the Codex Atlanticus, Leonardo da Vinci drew three 'easily movable' bridges, but one of them is enigmatic: all 'replicas' in Leonardo museums and exhibitions come as a surprise, to say the least, to any engineer or architect whose attention is drawn to it. This is the case for models in Amboise (France), Chicago and Portland (USA), Florence (Italy) and for the one of the traveling exhibition by the Australian company 'Grande Exhibitions' that already visited 40 major cities in the world. All 'replicas' of the bridge model attributed to Leonardo have pillars standing on the deck of the bridge, while the deck is suspended by cables attached on these pillars. At first sight this problem does not catch the attention of the observer, as the bridge seems to be a mixed form of a beam and a suspension bridge, but it was not overlooked by my colleague architect-engineer Dr. Laurens Luyten (Gent, Belgium). Yet, after a TV-interview in Brussels so much pressure was exerted by some of the museum col...

  20. River ice jams at bridges

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D. [New Brunswick Dept. of Transportation, Fredericton, NB (Canada); Beltaos, S. [National Water Research Institute, Burlington, ON (Canada)

    2000-12-01

    Ice jamming, known to cause high water levels at even moderate river flows, is described as both the main and least understood source of ice-related bridge damages. This paper describes a joint study by the New Brunswick Department of Transportation, the Department of the Environment, local governments, and the National Water Research Institute, designed to address problems associated with the interaction of ice jams and bridges. The study consists of collecting information at each of four sites in New Brunswick including: historical data on ice jam locations, causes, and water levels; channel bathymetry, width and slope within each study centred at the respective bridge; and documentation of ice conditions throughout the ice season, including measurement of ice cover thickness, observation of breakup mechanisms, times, causes, characteristics and possible impacts of ice jam release. Data analysis will include determination of high stages due to ice jams or surges caused by upstream ice jam releases, scour potential of surges, and quantification of the structure's capacity to restrain ice movement and to cause jams. The principal objective of the study is to advance beyond empiricism and to develop rational design criteria for bridges by anticipating the effects of climate changes and by incorporating local meteorological and hydrometric records into bridge design for added safety.

  1. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  2. Synthesis and Anticonvulsant Properties of New 3,3-Diphenyl-2,5-dioxo-pyrrolidin-1-yl-acetamides and 3,3-Diphenyl-propionamides.

    Science.gov (United States)

    Obniska, Jolanta; Rapacz, Anna; Rybka, Sabina; Góra, Małgorzata; Żmudzki, Paweł; Kamiński, Krzysztof

    2017-04-01

    The focused library of new amides derived from 3,3-diphenyl-2,5-dioxo-pyrrolidin-1-yl-acetic acid (2a-t) and 3,3-diphenyl-propionic acid (3a-t) as potential anticonvulsant agents was synthesized. The final products were obtained in the amidation reaction of the given carboxylic acid (2, 3) with appropriate secondary amines in the presence of carbonyldiimidazole (CDI) as a coupling reagent. The initial anticonvulsant screening was performed in mice intraperitoneally (i.p.) using the "classical" maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure models, whereas the acute neurological toxicity was determined applying the rotarod test. Additionally, several compounds were studied also in the 6-Hz seizures recognized as the animal model of human pharmacoresistant epilepsy. In this series, compound 3q displayed a broad spectrum of activity across the preclinical seizure models (ED50 MES = 31.64 mg/kg; ED50 scPTZ = 75.41 mg/kg, ED50 6-Hz (32 mA) = 38.15 mg/kg). Consequently, compound 3q revealed a wider spectrum of protection, higher activity or/and a better safety profile than the commonly used antiepileptic drugs such as phenytoin, ethosuximide, valproic acid, or/and levetiracetam. Notably, the in vitro studies showed that the most possible mechanism of action of 3q may be connected to the interaction with neuronal voltage-sensitive sodium channels (site 2). Other substances were active predominantly in the chemically induced seizures. The results of the current studies indicate that the presence of the pyrrolidine-2,5-dione ring is important but not indispensable for anticonvulsant activity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...... if the window has an U-factor of 1 W/(m2·K) or lower. This paper describes the development of modern, energy efficient Danish windows with reduced thermal bridges. It focuses on materials, geometry, and sealing of window panes based on a literature review. Examples of modern windows are presented. Experience...... with the minimum acceptable surface temperature regarding surface condensation or mold growth, implemented in the Danish Building Regulations in 2010, and the calculation method for this temperature based on international standards is discussed. The introduction of the minimum acceptable surface temperature has...

  4. Contactless Bridge Weigh-in-Motion

    OpenAIRE

    Ojio, T.; Carey, Ciaran; O'Brien, Eugene J.; Doherty, C; Taylor, S E

    2016-01-01

    Bridge weigh-in-motion (WIM) uses existing bridges to find the weights of vehicles that pass overhead. Contactless bridge weigh-in-motion (cBWIM) uses bridges to weigh vehicles without the need for any sensors to be attached to the bridge. A camera is mounted on the back of a telescope, which magnifies the image to the extent that submillimeter bridge deflections can be measured accurately. A second camera is used to monitor traffic and to determine axle spacings. The two cameras are synchron...

  5. Bridging faults in BiCMOS circuits

    Science.gov (United States)

    Menon, Sankaran M.; Malaiya, Yashwant K.; Jayasumana, Anura P.

    1993-01-01

    Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology for many high performance digital and mixed signal applications. Recent investigations revealed that bridging faults can be a major failure mode in IC's. Effects of bridging faults in BiCMOS circuits are presented. Bridging faults between logical units without feedback and logical units with feedback are considered. Several bridging faults can be detected by monitoring the power supply current (I(sub DDQ) monitoring). Effects of bridging faults and bridging resistance on output logic levels were examined along with their effects on noise immunity.

  6. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

    Brito, J. de; Branco, F. A.; Thoft-Christensen, Palle

    1997-01-01

    management systems are presently being implemented by bridge authorities in several countries. The prototype of an expert system for concrete bridge management is presented in this paper, with its functionality relying on two modules. The inspection module relies on a periodic acquisition of field......The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...

  7. Balanced bridge feedback control system

    Science.gov (United States)

    Lurie, Boris J. (Inventor)

    1990-01-01

    In a system having a driver, a motor, and a mechanical plant, a multiloop feedback control apparatus for controlling the movement and/or positioning of a mechanical plant, the control apparatus has a first local bridge feedback loop for feeding back a signal representative of a selected ratio of voltage and current at the output driver, and a second bridge feedback loop for feeding back a signal representative of a selected ratio of force and velocity at the output of the motor. The control apparatus may further include an outer loop for feeding back a signal representing the angular velocity and/or position of the mechanical plant.

  8. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  9. Optimum selection on bridge erection with floating crane in East China Sea Bridge and Hangzhou Bay Bridge

    Institute of Scientific and Technical Information of China (English)

    Shunquan Qin; Pu Zhou; Youheng Hua

    2004-01-01

    @@ Introduction With the rapid development of China′s economy, many bridges will be built over the Chinese coastal waters of Pacific Ocean. Among them, construction of East China Sea Bridge has been commenced in June 2001, and will be completed at the end of 2005, Hangzhou Bay Bridge was also started to construct in June 2003(Fig. 1). These two ultralong bridges are designed as twin expressway bridges standing side by side each carries a 3-lane one-way carriageway. The total width is 31.5m and 33.0m respectively. East China Sea Bridge starts from Nanhui District, Shanghai and extends to the Yangshan Deep Water Port Area, which is located at one of the Qiqu Islands. The total length of the bridge is about 31.0 km, in which 25 km are on the sea, and 22 km is in the unnavigable region. Hangzhou Bay Bridge across the mouth of Qiantang River.

  10. Is myocardial bridging a bridge connecting to cardiovascular events?

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun

    2010-01-01

    @@ Coronary arteries and their major branches usually course on the surface of the heart in the subepicardial tissue. However, a muscle hber overlying the intramyocardial segment of an epicardial coronary artery was defined as myocardial bridging (MB), and subsequently the artery coursing within the myocardium is called a tunneled artery.

  11. Acaricides efficiency on Rhipicephalus (Boophilus microplus from Bahia state North-Central region Eficiência de acaricidas sobreRhipicephalus (Boophilus microplusna região Centro-Norte, Bahia

    Directory of Open Access Journals (Sweden)

    José Tadeu Raynal

    Full Text Available The cattle tick Rhipicephalus (Boophilus microplus is responsible for major losses in the Brazilian livestock, mainly due to reduction in cattle productive performance. Resistance development to major classes of acaricide widely used nowadays has been extensively reported, as well as the occurrence of residues from these compounds in animal products and the environment. This study aimed to evaluate the efficiency of acaricides on R. (B. microplus collected from rural properties in the North-Central region of Bahia State. Ticks were collected in several cattle farms in the cited region, and an in vitro acaricide efficiency assay was performed based on the immersion of ticks in acaricide solutions made according to manufacturers' recommendations. The results obtained in the experiments indicated varying degrees of efficiency of the several bases studied, with the products benzofenilurea, macrocyclic lactone and fipronil showing the highest levels of efficiency, 100%, 100% and 97.34%, respectively. It was possible to conclude that, for the region studied, there are different degrees of commercial acaricides efficiency, and many present less than 95% effectiveness, value determined as acceptable by the Brazilian legislation.O carrapato Rhipicephalus (Boophilus microplus é responsável por grandes perdas na pecuária brasileira, principalmente devido à redução no desempenho produtivo dos animais. A resistência do parasita a diferentes classes de acaricidas tem sido amplamente relatada, bem como os problemas de ocorrência de resíduos desses compostos em produtos de origem animal e no ambiente. Esse estudo teve como objetivo avaliar a eficiência de diversos acaricidas sobre populações de R. (B. microplus provenientes de propriedades rurais da Região Centro-Norte do Estado da Bahia, Brasil. Teleóginas ingurgitadas foram colhidas em diferentes propriedades da região e submetidas a ensaio in vitro de eficiência de acaricidas, baseado na

  12. Oxidation Reactivity Channels for 2-(Pyridin-2-yl)-N,N-diphenyl-acetamides

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, Sylvie [University of New Mexico, Albuquerque; Binyamin, Iris [University of New Mexico, Albuquerque; Kim, Sung-jun [University of New Mexico, Albuquerque; Deck, Lorraine M. [University of New Mexico, Albuquerque; Rapko, Brian M. [Pacific Northwest National Laboratory (PNNL); Hay, Benjamin [ORNL; Duesler, Eileen N. [University of New Mexico, Albuquerque; Paine, Robert T. [University of New Mexico, Albuquerque

    2007-11-01

    Synthetic routes to 2-(pyridin-2-yl)-N,N-diphenylacetamide and 2-(6-methylpyridin-2-yl)-N,N-diphenyl-acetamide are described along with results from the chemical oxidation of these compounds with peracetic acid, m-chloroperbenzoic acid, and OXONE. In each case, oxidations generate four products in varying amounts depending on the oxidant and reaction conditions. Each product has been characterized by spectroscopic methods and the molecular structures of several of the new compounds have been confirmed by X-ray crystallography.

  13. Polybrominated diphenyl ether (PBDE) flame retardants: environmental contamination, human body burden and potential adverse health effects.

    Science.gov (United States)

    Costa, Lucio G; Giordano, Gennaro; Tagliaferri, Sara; Caglieri, Andrea; Mutti, Antonio

    2008-12-01

    Polybrominated diphenyl ethers (PBDEs) are an important class of flame retardants, widely used in a variety of consumer products. In the past several years, PBDEs have become widespread environmental pollutants, and have been detected in water, soil, air, animals and human tissues. Exposure occurs in particular through the diet and the indoor environment. Infants and toddlers have the highest body burden, due to exposure via maternal milk and through house dust. Tetra-, penta- and hexa-BDEs are the congeners most commonly found in humans. Recent concerns on possible adverse health effects of PBDEs are focusing on their potential endocrine disrupting effects and on developmental neurotoxicity.

  14. The research of human exposure to polybrominated diphenyl ethers and perfluoroocatane sulfonate

    Institute of Scientific and Technical Information of China (English)

    WANG YaWei; JIANG GuiBin

    2008-01-01

    As two kinds of emerging chemicals, the pollution of polybrominated diphenyl ethers (PBDEs) and perfluoroocatane sulfonate (PFOS) has been becoming a global environmental problem. Also, research of the transport, transfer, bioaccumulation in organism, and toxicology of these two kinds of pollutant is a hotspot in environmental sciences now. In this paper, we summarize and critically review the status and progress of PBDEs and PFOS exposure to human beings. Further, data analyses based on statistical methods are done to study the characters of PBDEs and PCBs concentrations in different regions in the world.

  15. Synthesis and in vitro evaluation of new diphenyl ether derivatives as serotonin transporter ligands

    Institute of Scientific and Technical Information of China (English)

    GUO YunHang; CHEN XiangJi; JIA HongMei; DEUTHER-CONRAD Winnie; BRUST Peter; STEINBACH Jorg; VERCOUILLIE Johnny; LIU BoLi

    2008-01-01

    For the development of new ligands as potential imaging agents for the serotonin transporter (SERT), a series of diphenyl ether derivatives have been synthesized, characterized, and evaluated for their in vitro binding affinities to the SERT. Among the above compounds, 2-(2-((dimethylamino)methyl)-4-fluoro-phenoxy)-5-bromobenzenamine (15) and 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-iodobenzene respectively. They can be further labeled with carbon-11, fluorine-18, iodine-123 or bromine-76, and evaluated as useful imaging agents for the SERT. Moreover, the study of the structure-activity relationship (SAR) provides some useful information for the future design of new ligands.

  16. Chemical consequences of the (n,el) reaction in diphenyl selenium

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, C.; Bulbulian, S.; Archundia, C.

    1985-10-01

    The products formed during thermal neutron irradiation of diphenyl selenium were analyzed by gas chromatography. Possible reaction mechanisms are discussed to explain the principal reaction product observed. The organic yields of sup(75)Se, sup(83)Se and sup(81m)Se are determined. The retention values obtained are 9.7 +- 2.0, 8.3 +- 1.1 and 10.4 +- 2.1, respectively. These low values indicate that in all three cases most of the molecules are broken after the (n,el) process. No isotope effect was observed. (author). 13 refs.

  17. [N,N-Bis(diphenyl­phosphino)isopropyl­amine]dibromidonickel(II)

    OpenAIRE

    Hapke, Marko; Wöhl, Anina; Peitz, Stephan; Müller, Bernd H.; Spannenberg, Anke; Rosenthal, Uwe

    2009-01-01

    The title compound, [NiBr2(C27H27NP2)], was synthesized by the reaction of NiBr2(dme) (dme is 1,2-dimethoxy­ethane) with N,N-bis­(diphenyl­phosphino)isopropyl­amine in methanol/tetra­hydro­furan. The nickel(II) center is coordinated by two P atoms of the chelating PNP ligand, Ph2PN(iPr)PPh2, and two bromide ions in a distorted square-planar geometry.

  18. 多溴联苯醚的胚胎毒性%Embryotoxicity of Polybrominated Diphenyl Ethers

    Institute of Scientific and Technical Information of China (English)

    于永利; 杨景峰; 魏素香; 董武

    2013-01-01

    多溴联苯醚(polybrominated diphenyl ethers,PBDEs)是一种非常优质的阻燃剂,在日常生活中有广泛的应用,但由于PBDE及其代谢产物OH-PBDEs具有扰乱甲状腺素作用而被研究学者关注.本文对PBDEs和OH-PBDEs引起的早期胚胎毒性及对去碘酶的影响作了相关综述.

  19. The Sequestration of Oxy-Polybrominated Diphenyl Ethers in the Nudibranchs Miamira magnifica and Miamira miamirana

    OpenAIRE

    2016-01-01

    A series of oxy-polybrominated diphenyl ethers (O-PBDEs) has been isolated from the extracts of Miamira magnifica and Miamira miamirana collected from Queensland, Australia. M. magnifica sequesters the new OH-PBDE 1 and six known OH-PBDEs containing four to six bromines (2–7). M. miamirana also accumulates known tribromo- and tetrabromo OMe-PBDEs 8–10 in both mantle and viscera tissues. To date, Miamira is the only genus of the family Chromodorididae that is known to incorporate O-PBDEs, rath...

  20. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  1. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

    A signal-to-noise analysis is made of the Wheatstone bridge, where the unknown and standard resistors may be at different temperatures, a situation which occurs in resistance thermometry. The limiting condition is assumed to be dissipation in the unknown resistor. It is shown that the ratio arms ...

  2. Intercellular bridges in vertebrate gastrulation.

    Directory of Open Access Journals (Sweden)

    Luca Caneparo

    Full Text Available The developing zebrafish embryo has been the subject of many studies of regional patterning, stereotypical cell movements and changes in cell shape. To better study the morphological features of cells during gastrulation, we generated mosaic embryos expressing membrane attached Dendra2 to highlight cellular boundaries. We find that intercellular bridges join a significant fraction of epiblast cells in the zebrafish embryo, reaching several cell diameters in length and spanning across different regions of the developing embryos. These intercellular bridges are distinct from the cellular protrusions previously reported as extending from hypoblast cells (1-2 cellular diameters in length or epiblast cells (which were shorter. Most of the intercellular bridges were formed at pre-gastrula stages by the daughters of a dividing cell maintaining a membrane tether as they move apart after mitosis. These intercellular bridges persist during gastrulation and can mediate the transfer of proteins between distant cells. These findings reveal a surprising feature of the cellular landscape in zebrafish embryos and open new possibilities for cell-cell communication during gastrulation, with implications for modeling, cellular mechanics, and morphogenetic signaling.

  3. A Rapidly Deployable Bridge System

    Science.gov (United States)

    2013-01-15

    A Rapidly Deployable Bridge System Gareth R. Thomas1 and Bernard J. Sia2 1ATA Engineering, 11995 El Camino Real, San Diego, CA 92130; PH (858) 480...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) ATA Engineering,11995 El Camino Real,San Diego,CA,92130 8. PERFORMING ORGANIZATION REPORT NUMBER

  4. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  5. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...

  6. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on archit

  7. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    , considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  8. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m...... in the Strömsund Bridge (from 1955) to 890 m in the Tatara Bridge (from 1999)....

  9. Diphenyl chlorothiophosphonate

    Directory of Open Access Journals (Sweden)

    Yan-Fei Zhang

    2011-11-01

    Full Text Available The complete molecule of the title compound, C12H10ClO2PS, is generated by crystallographic mirror symmetry, with the P, S and Cl atoms lying on the mirror plane. The resulting PO2SCl tetrahedron is significantly distorted [O—P—O = 96.79 (9°]. The crystal packing exhibits no directional interactions.

  10. Field performance of timber bridges. 5, Little Salmon Creek stress-laminated deck bridge

    Science.gov (United States)

    M. A. Ritter; J. A. Kainz; G. J. Porter

    The Little Salmon Creek bridge was constructed in November 1988 on the Allegheny National Forest in Pennsylvania. The bridge is a simple span, single-lane, stress-laminated deck superstructure that is approximately 26-ft long and 16-ft wide. The bridge is unique in that it is the first known stress-laminated timber bridge to be constructed of hardwood lumber. The...

  11. Field performance of timber bridges. 6, Hoffman Run stress-laminated deck bridge

    Science.gov (United States)

    M. A. Ritter; P. D. Hilbrich Lee; G. J. Porter

    The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was...

  12. Building Bridges One Line at a Time

    Science.gov (United States)

    Grigsby, Cathy Murray

    2012-01-01

    In this article, first-grade students were taught the different kinds of lines that were part of the construction of various bridges--the curved lines of the arches of stone bridges, straight lines connecting the cables of a suspension bridge, vertical lines, horizontal lines, and so on. They gained practice in drawing structures and in fine brush…

  13. Comparison between Modern Violin Bridge and Baroque Violin Bridge by Photoelastic Observation and Frequency Analysis

    Science.gov (United States)

    Matsutani, Akihiro

    2004-05-01

    A comparison between the modern bridge and the baroque bridge of the violin by photoelastic observation was carried out. The relationship between the stress part and the hole is symmetric in the modern and baroque bridges. The measured spectral envelopes of baroque bridges are similar to those of modern bridges in D- or G-strings, and have peaks at a frequency higher than those of modern bridges in E-string. The visualization method as used in this study may provide hints for the design of violin bridges.

  14. ESTIMATION OF ECONOMIC EXPEDIENCY OF «BRIDGE-PRE-BRIDGE TERRITORY» SYSTEM

    Directory of Open Access Journals (Sweden)

    A. A. Lapko

    2008-01-01

    Full Text Available The paper considers principles that form «Bridge-Pre-Bridge Territory» system. The method is proposed for calculation of expenses on technical research for development of projects on usage of pre-bridge territories. Usage of site class number for natural conditions makes it possible to estimate investment attractiveness of «Bridge-Pre-Bridge Territory» system.

  15. Brominated diphenyl ethers in the sediments, porewater, and biota of the Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K.; Klosterhaus, S.; Liebert, D.; Stapleton, H. [Maryland Univ., Solomons, MD (United States)

    2004-09-15

    Levels of brominated diphenyl ethers (BDEs) are rapidly increasing in the environment, and in a short time these chemicals have evolved from 'emerging contaminants' to globally-distributed organic pollutants. Recent research demonstrates BDEs are sufficiently stable to be transported long distances in the environment and to accumulate in higher trophic levels. Photolysis and metabolism appear to be dominant loss processes for the parent compounds, generating a variety of lower brominated diphenyl ethers, hydroxylated metabolites, and other products. BDEs are hydrophobic, and therefore their transport in aquatic systems is likely controlled by sorption to sediments and perhaps exchange across the air-water interface. To date, few studies have examined the geochemistry of BDEs in natural waters. In this paper, we review our recent measurements of BDEs in the Chesapeake Bay, a shallow, productive estuary in eastern North America. We focus on the distribution of BDE congeners sediment, porewater, and in faunal benthos along a contamination gradient downstream from a wastewater treatment plant and on the spatial distribution of BDEs in bottom-feeding and pelagic fish species.

  16. An overview of polybrominated diphenyl ethers (PBDEs) in the marine environment

    Science.gov (United States)

    Lee, Hyo Jin; Kim, Gi Beum

    2015-06-01

    Polybrominated diphenyl ethers (PBDEs), which are used extensively as brominated flame retardants, are found ubiquitously in marine environments worldwide. In this paper, we review all available data on the occurrence and trends of PBDEs in marine environments. PBDE levels in different marine environmental compartments vary from nanograms per gram to micrograms per gram, and differ widely, depending on the exposed species and the collection site. The PBDE congener profiles in biota, which are dominated by the lower brominated congeners, such as BDE-47 and BDE-99, are different from those in sediments, where BDE-209 is dominant. Temporal trends in PBDE levels in sediment cores vary considerably, depending on the region or country studied, with possible correlations with the historic and current use of PBDEs. Low brominated BDE congeners have the potential for bioaccumulation in marine organisms, but BDE- 209 has a very low potential for bioaccumulating within the marine food web. The toxicological effects of PBDEs on marine organisms are largely unknown. However, PBDE isomers may be sufficient to elicit adverse effects in some marine organisms. Here, we discuss naturally occurring brominated diphenyl ethers and recommend further research to improve future monitoring.

  17. Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in biosolids from municipal wastewater treatment plants in China.

    Science.gov (United States)

    Sun, Jianteng; Liu, Jiyan; Liu, Qian; Ruan, Ting; Yu, Miao; Wang, Yawei; Wang, Thanh; Jiang, Guibin

    2013-03-01

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) along with methoxylated polybrominated diphenyl ethers (MeO-PBDEs) have been frequently identified as natural compounds in marine environment and also assumed as metabolites of PBDEs. In the present study, nine OH-PBDE, nine MeO-PBDE and 10 PBDE congeners were studied in the sewage sludge collected from 36 municipal wastewater treatment plants (WWTPs) in 27 cities of China. The results suggest that OH-PBDEs and PBDEs are ubiquitous in sewage sludge in China, however, methoxylated PBDEs were not detectable. Composition profiles of detected OH-PBDE congeners were different depending on the sampling location. ΣOH-PBDEs in WWTPs sludge ranged from 0.04 to 2.24 ng g(-1) dry weight (mean: 0.35 ng g(-1) dry weight). The total amount of the two most prominent congeners (6-OH-BDE-47+2'-OH-BDE-68) accounted for about 53.3-100% of the sum of all six identified congeners. A significant linear relationship was found between 6-OH-BDE-47 and 2'-OH-BDE-68. A distinct geographical distribution of ΣOH-PBDEs was observed with greater concentrations of OH-PBDEs at coastal areas than inland regions in China.

  18. Polybrominated diphenyl ethers (PBDEs) in feathers of colonial water-bird species from Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Riffat Naseem, E-mail: r_n_malik2000@yahoo.co.uk [Environmental Biology Laboratory, Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PO 45320 (Pakistan); Moeckel, Claudia [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Jones, Kevin C.; Hughes, David [Centre for Chemicals Management, Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ (United Kingdom)

    2011-10-15

    Feathers of two colonial water-birds species (Bubulcus ibis, Egretta garzetta) from four heronries in the Punjab province, Pakistan were analysed for 28 Polybrominated Diphenyl Ethers (PBDEs) congeners. Median concentrations of {Sigma}PBDEs were 2.41 and 1.91 ng/g in little and cattle egrets. PBDE-47, -100, -138, -153 were abundant and detected in >70% of feather samples in both species. Species-specific differences based on dietary preferences indicated higher concentration of PBDE-47, -66, -75, -100, -153, -154, and -183 in fish eating little egret. BDE-47 and -100 were more frequent in little egrets and BDE-99 was more dominant in cattle egret which feed on terrestrial habitat. Higher {Sigma}hexa- and hepta-BDEs congeners showed larger concentrations in feathers from heronries close to water bodies which receive urban and industrial effluents whereas lower-brominated congeners (BDE-47-BDE-100) dominated in rural/agricultural regions. Hazard quotients (HQs) indicated that measured {Sigma}PBDEs pose no risk to egret population. - Highlights: > Feathers as non-destructive tool to asses Polybrominated Diphenyl Ethers (PBDEs) contamination. > PBDE-47 and -100 frequent in feathers of fish eating egrets. > BDE-99 dominant in feathers of egrets feed in terrestrial habitats. > Lower-brominated congeners (BDE-47-BDE-100) dominate in feathers from rural areas. > Greater contents of hexa- and hepta-BDEs in feathers from areas receive urban/industrial effluents. - Feathers are used as a biomonitoring tool for PBDEs contamination.

  19. Characterization of the molecular degradation mechanism of diphenyl ethers by Cupriavidus sp. WS.

    Science.gov (United States)

    Wang, Sheng; Bai, Naling; Wang, Bing; Feng, Zhuo; Hutchins, William C; Yang, Ching-Hong; Zhao, Yuhua

    2015-11-01

    Commonly used flame retardants, such as polybrominated diphenyl ethers, are extremely persistent in the environment, causing serious environmental risks. Certain strains of bacteria are able to degrade several low brominated congeners of PBDEs aerobically. However, the aerobic degradation pathway is not yet well understood, particularly at the genetic level. In this study, we isolated Cupriavidus sp. WS from the environment that could degrade diphenyl ether (DE), 4-bromodiphenyl ether, and 4,4'-bromodiphenyl ether. DE was completely degraded in 6 days without any detectable end-product. Using transposon mutagenesis, several DE degradation-deficient mutants were obtained. Knocking out bphA1, bphA2, and bphA3 eliminated the ability of the Cupriavidus sp. WS bacterium to degrade DE, indicating that the bph genes play a crucial role in DE degradation by this strain. The specific roles of bphA, bphB, and bphC were identified by systematically expressing these genes in Escherichia coli. The dihydrodiol product of BphA was dehydrogenated into 2,3-dihydroxydiphenyl ether by BphB. 2,3-Dihydroxydiphenyl ether was then decomposed into phenol and 2-pyrone-6-carboxylic acid by BphC. Thus, BphA, BphB, and BphC act sequentially in the aerobic degradation of DE, 4-bromodiphenyl ether, and 4,4'-dibromodiphenyl ether by the Cupriavidus sp. WS bacterium.

  20. Bioaccumulation of polybrominated diphenyl ethers (PBDEs) in sediment aged for 2 years to carps (Cyprinus carpio)

    Science.gov (United States)

    Tian, S. Y.; Li, J. Y.; Jia, X. M.

    2017-08-01

    In order to understand the risk of polybrominated diphenyl ethers (PBDEs) existing in sediment for years, the accumulation of PBDEs in sediment aged for 2 years to fish was investigated. Simulated aquatic system microcosms were conducted with PBDE contaminated sediment aged for 2 years and carps were cultured in the microcosms for 20 days. PBDE concentrations in carp tissues were analyzed to estimate the bioavailability of aged PBDEs in carps. The main spiked PBDE congeners were detected in sediment even though the contaminated sediment was aged for 2 years. Similarly, the five PBDE (BDE-28, 47, 100, 153 and 154) congeners which probably were bioaccumulated by carp were detected in fish tissues, indicating that PBDEs could be bioaccumulated after aging for 2 years. The PBDEs distribution revealed that the concentrations of polybrominated diphenyl ethers in tissues of Cyprinus carpio is in this order of magnitude: gut > liver > gill > fillet. The PBDEs concentrations in fillet were as high as 67.9 ng/g dry wt, in which BDE-47 contributed almost 50% in profile.

  1. Levels and distribution of polybrominated diphenyl ethers in various tissues of birds of prey

    Energy Technology Data Exchange (ETDEWEB)

    Voorspoels, Stefan [Department of Pharmacy, Toxicology Division, University of Antwerp, CDE-gebouw S, Universiteitsplein 1, B-2610 Wilrijk (Belgium)]. E-mail: stefan.voorspoels@ua.ac.be; Covaci, Adrian [Department of Pharmacy, Toxicology Division, University of Antwerp, CDE-gebouw S, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Lepom, Peter [Department of Pharmacy, Toxicology Division, University of Antwerp, CDE-gebouw S, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Jaspers, Veerle L.B. [Department of Pharmacy, Toxicology Division, University of Antwerp, CDE-gebouw S, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Schepens, Paul [Department of Pharmacy, Toxicology Division, University of Antwerp, CDE-gebouw S, Universiteitsplein 1, B-2610 Wilrijk (Belgium)

    2006-11-15

    In the present study, concentrations and tissue distribution of polybrominated diphenyl ethers (PBDEs; IUPAC nos. 28, 47, 99, 100, 153, 154, 183, and 209) were examined in brain, adipose tissue, liver, muscle, and serum of birds of prey. Median {sigma}PBDE levels (BDE 28-183) in the tissues of sparrowhawks ranged from 360 to 1900 ng/g lipid weight (lw), which was in general one order of magnitude higher than in the tissues of common buzzards (26-130 ng/g lw). There were no differences in PBDE congener patterns between the various tissues within individuals of a certain species. Inter-species differences in PBDE patterns and in particular the percentage of BDE 99, 100 and 153 were, however, pronounced between sparrowhawk and common buzzard. BDE 209 was detected in nearly all serum and in some liver samples, but not in any other tissues. This observation suggests that exposure to BDE 209 is low or that this congener is poorly accumulated. Passive (lipid content related) diffusion could not completely describe the PBDE tissue distribution, e.g. the lowest PBDE-load was measured in brain, a fairly lipid rich tissue. - Distribution of polybrominated diphenyl ethers in birds of prey is tissue dependent.

  2. Polybrominated diphenyl ethers in articles: a review of its applications and legislation.

    Science.gov (United States)

    Jinhui, Li; Yuan, Chen; Wenjing, Xiao

    2017-02-01

    Polybrominated diphenyl ethers (PBDEs), especially commercial decabrominated diphenyl ethers (c-decaBDE), have been widely produced and applied to numerous materials because of their highly effective flame-retardant capabilities. The production of commercial pentaBDE (c-pentaBDE) and commercial octaBDE (c-octaBDE) ended in 2004 because they are persistent, bioaccumulative, and toxic to both humans and the environment, but decaBDE production and use continue. Furthermore, many congeners of PBDEs are still prevalent in consumer products and articles that they pose enormous threat to both the environment and human health. PBDEs have been detected in the casing of electrical and electronic equipment, textile materials, automotive interiors, polyurethane foam (PUF) in seat cushions, children's toys, kitchenware, and other products. With increasing evidence about PBDE pollution and the adoption of international conventions, many developed countries have drawn more public attention to PBDEs and developed sound strategies for their management. This review summaries the utilization and management of PBDEs in a number of countries and reaches the conclusion that PBDEs are still prevalent in consumer articles, while specific regulations or policies for articles containing PBDEs are rare. Public awareness should be raised on the importance of sound management of articles containing PBDEs.

  3. Beginning Course Surveys: Bridges for Knowing and Bridges for Being

    Directory of Open Access Journals (Sweden)

    David Starr-Glass

    2011-06-01

    Full Text Available The use of a participant survey, administered at the outset of an online course, can provide information useful in the management of the learning environment and in its subsequent redesign. Such information can clarify participants’ prior experience, expectations, and demographics. But the very act of enquiring about the learner also signals the instructor’s social presence, relational interest, and desire to enter into an authentic dialogue. This study examines the use of participant surveys in online management courses. The first section discusses the informational bridges that this instrument provides. The second section considers survey responses to open-ended questions dealing with student sentiments. This analysis suggests that the survey plays a valuable part in accentuating social presence and in initiating relational bridges with participants.

  4. 33 CFR 115.70 - Advance approval of bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges...

  5. Evaluation of In Vivo Acaricidal Effect of Soap Containing Essential Oil of Chenopodium ambrosioides Leaves on Rhipicephalus lunulatus in the Western Highland of Cameroon

    Directory of Open Access Journals (Sweden)

    Marc K. Kouam

    2015-01-01

    Full Text Available A study on the acaricidal properties of foam soap containing the essential oil of Chenopodium ambrosioides leaves was carried out on Rhipicephalus lunulatus. Four doses (0.03, 0.06, 0.09, and 0.12 µL of essential oil per gram of soap and a control (soap without essential oil with four replications for each treatment were used for in vitro trial. Each replication consisted of 10 ticks in a Petri dish with filter paper impregnated with the foam soap on the bottom. Following in vitro trials, three doses (0.06, 0.09, and 0.12 µL/g and the control in two replications were selected for in vivo test based on mortality rate recorded from the in vitro trial. Each replication was made up of 10 goats naturally infested with ticks. Results show that soap containing essential oil is toxic to R. lunulatus. The in vivo mortality rate in the control on day 8 was 22.69% whereas the highest dose (0.12 µL/g killed 96.29% of the ticks on day 8. The LD50 of the foam soap containing essential oil was 0.037 and 0.059 µL/g on day 2 in the laboratory and on the farm, respectively. This indicates the potentially high efficiency of this medicated soap on this parasite.

  6. Evaluation of In Vivo Acaricidal Effect of Soap Containing Essential Oil of Chenopodium ambrosioides Leaves on Rhipicephalus lunulatus in the Western Highland of Cameroon.

    Science.gov (United States)

    Kouam, Marc K; Payne, Vincent K; Miégoué, Emile; Tendonkeng, Fernand; Lemoufouet, Jules; Kana, Jean R; Boukila, Benoit; Pamo, E Tedonkeng; Mnm, Bertine

    2015-01-01

    A study on the acaricidal properties of foam soap containing the essential oil of Chenopodium ambrosioides leaves was carried out on Rhipicephalus lunulatus. Four doses (0.03, 0.06, 0.09, and 0.12 µL of essential oil per gram of soap) and a control (soap without essential oil) with four replications for each treatment were used for in vitro trial. Each replication consisted of 10 ticks in a Petri dish with filter paper impregnated with the foam soap on the bottom. Following in vitro trials, three doses (0.06, 0.09, and 0.12 µL/g) and the control in two replications were selected for in vivo test based on mortality rate recorded from the in vitro trial. Each replication was made up of 10 goats naturally infested with ticks. Results show that soap containing essential oil is toxic to R. lunulatus. The in vivo mortality rate in the control on day 8 was 22.69% whereas the highest dose (0.12 µL/g) killed 96.29% of the ticks on day 8. The LD50 of the foam soap containing essential oil was 0.037 and 0.059 µL/g on day 2 in the laboratory and on the farm, respectively. This indicates the potentially high efficiency of this medicated soap on this parasite.

  7. Acaricide rotation strategy for managing resistance in the tick Rhipicephalus (Boophilus) microplus (Acarina: Ixodidae): laboratory experiment with a field strain from Costa Rica.

    Science.gov (United States)

    Thullner, Friederike; Willadsen, Peter; Kemp, David

    2007-09-01

    During the past two decades, resistance to pyrethroids within the cattle tick genus Boophilus has caused tick control problems in various tropical countries, mainly in Latin America, southern Africa, Australia, and New Caledonia. A Rhipicephalus (Boophilus) microplus (Canestrini) strain from Costa Rica, exhibiting resistance to the pyrethroid deltamethrin but only a very low resistance to organophosphates (OP) was kept under selection pressure for 9 to 11 generations by using deltamethrin or coumaphos (OP), either exclusively or in rotation. The objective of this acaricide rotation was to examine the possibility of delaying or reducing the full emergence of pyrethroid resistance. In the substrain selected with deltamethrin at the LD50 concentration, resistance to deltamethrin was measured after five generations (resistance factor [RF] = 9.2) and very high resistance after 11 generations (RF = 756), compared with the starting field strain from Costa Rica. In the substrain selected with deltamethrin then coumaphos in rotation, resistance to deltamethrin was variable from one generation to the next (RF = 1-4.2), but no high, stable resistance developed. After 10 generations of rotation, the deltamethrin RF was 1.6. In the substrains selected continuously with coumaphos or coumaphos and deltamethrin in rotation, no consistent change in resistance to coumaphos was observed. Rotation of deltamethrin with coumaphos seems to delay the development of strong resistance to deltamethrin in a population that had initially a low level of deltamethrin resistance.

  8. Comparison of 3 tests to detect acaricide resistance in Boophilus decoloratus on dairy farms in the Eastern Cape Province, South Africa

    Directory of Open Access Journals (Sweden)

    S. Mekonnen

    2003-06-01

    Full Text Available The susceptibility of the larval offspring of engorged female Boophilus decoloratus, and of the engorged females, collected from cattle on the dairy farms Brycedale, Sunny Grove and Welgevind in the Eastern Cape Province, South Africa, was tested against the acaricides amitraz, chlorfenvinphos and cypermethrin. Resistance was determined by means of the Shaw Larval Immersion Test (SLIT for larvae and the Reproductive Estimate Test (RET and Egg Laying Test (ELT for adults. At Brycedale the tests all indicated resistance to chlorfenvinphos, and RET and ELT indicated resistance to amitraz and emerging resistance to cypermethrin. At Sunny Grove, B. decoloratus was resistant to cypermethrin using SLIT and exhibited emerging resistance to chlorfenvinphos with SLIT and to cypermethrin with both RET and ELT. At Welgevind, resistance was recorded against chlorfenvinphos (SLIT and against cypermethrin (ELT, and emerging resistance against permethrin (RET. The results obtained with RET and ELT were generally comparable, but often differed from those obtained with SLIT. Resistance could be detected within 7 days with ELT compared to 42 days with RET and 60 days with SLIT.

  9. Acaricidal activity of Annonaceae fractions against Tetranychus tumidus and Tetranychus urticae (Acari: Tetranychidae and the metabolite profile of Duguetia lanceolata (Annonaceae using GC-MS

    Directory of Open Access Journals (Sweden)

    Dejane Santos Alves

    2015-12-01

    Full Text Available Species of the Tetranychus genus feed on plant tissues, which reduces the rate of photosynthesis and can lead to the death of plant tissues. As a result, considerable production losses are caused by these arthropods. Thus, in order to aid in the development of new products for the control of Tetranychus tumidus Banks and Tetranychus urticae Koch (Acari: Tetranychidae, the initial objective of this study was to select Annonaceae derived fractions that were soluble in dichloromethane and have acaricidal activity. Then, an exploratory analysis of the metabolite profile of the most successful fraction was performed by gas chromatography-mass spectrometry (GC-MS. Among the dichloromethane soluble fractions derived from Annona cacans Warm., Annona coriacea Mart., Annona neolaurifolia H. Rainer, Annona sylvatica A.St.-Hil., Duguetia lanceolata A.St.-Hil., Guatteria australis A.St.-Hil., Xylopia brasiliensis Spreng., Xylopia emarginata Mart. and Xylopia sericea A.St.-Hil., only the fraction from D. lanceolata stem bark reduced the survival of T. tumidus females. However, ovicidal activity was not detected when D. lanceolata stem bark was evaluated against T. tumidus eggs. Further, we studied the effect of dichloromethane soluble fractions from D. lanceolata leaves, berry fruits and stem bark on T. urticae, and the stem bark was found to be the most active fraction against T. urticae. The metabolite profile analysis of D. lanceolata stem bark by GC-MS, suggested that the main constituents were 2,4,5-trimethoxystyrene and trans-asarone.

  10. Degenerative process and cell death in salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged female exposed to the acaricide permethrin.

    Science.gov (United States)

    Nodari, Elen Fernanda; Roma, Gislaine Cristina; Furquim, Karim Christina Scopinho; De Oliveira, Patrícia Rosa; Bechara, Gervásio Henrique; Camargo-Mathias, Maria Izabel

    2012-08-01

    Ticks are ectoparasites of great medical and veterinary importance around the world and synthetic chemicals such as permethrin have been used for their control. This study provides a cytochemistry analysis of both degenerative and cell death processes in salivary glands of the brown dog tick Rhipicephalus sanguineus semi-engorged females exposed to 206, 1,031, and 2,062 ppm of permethrin. The results presented herein demonstrate that permethrin is a potent chemical acaricide that would act on the glandular tissue's morphophysiology in this tick species by eliciting severe changes in the acinus shape, intense vacuolation of the acinar cells' cytoplasm, marked glandular tissue disorganization, culminating in an advanced degenerative stage with consequent formation of many apoptotic bodies (cell death). In addition, permethrin induced major changes in the acinar cells' nucleus, such as a change both in its shape and size, chromatin marginalization, nuclear fragmentation, and appearance of picnotic nuclei, especially when the highest concentrations of the product were used. Thus, permethrin induced early degeneration of this tissue characterized by significant changes in the structure of acinar cells and production of enzymes related to the cell death process, in addition to interfering directly in the genetic material of these cells. Copyright © 2012 Wiley Periodicals, Inc.

  11. Acaricidal activities of whole cell suspension, cell-free supernatant,and crude cell extract of Xenorhabdus stokiae against mushroom mite (Luciaphorus sp.)

    Institute of Scientific and Technical Information of China (English)

    Prapassom BUSSAMAN; Chirayu SA-UTH; Paweena RATTANAS ENA; Angsumarn CHANDRAPATYA

    2012-01-01

    Xenorhabdus bacterium has been used as a biological control agent against Luciaphorus sp.,a mushroom mite endemic in Thailand.To develop an effective formulation of Xenorhabdus stokiae,treatments using different parts of X.stokiae isolate PB09 culture,including whole cell suspension,cell-free supernatant,and crude cell extract,were performed.The results show that different parts ofX.stokiae isolate PB09 culture could induce variable effects on mite mortality and fecundity.Application with cell-free supernatant of X.stokiae culture resulted in both the highest mite mortality rate [(89.00+3.60)%] and the lowest mite fecundity [(41.33+23.69) eggs/gravid female].Whole cell suspension of X.stokiae isolate PB09 culture was found to be slightly less effective than its cell-free supernatant,suggesting that X.stokiae was more likely to release its metabolites with acaricidal activities to the surrounding culture media.Crude cell extract of X.stokiae was not effective against mites.Cell-free supernatant of X.stokiae isolate PB09 was the most effective biological control agent and it could be conveniently used in future formulations instead of live bacteria.

  12. Evaluation of In Vivo Acaricidal Effect of Soap Containing Essential Oil of Chenopodium ambrosioides Leaves on Rhipicephalus lunulatus in the Western Highland of Cameroon

    Science.gov (United States)

    Kouam, Marc K.; Payne, Vincent K.; Miégoué, Emile; Tendonkeng, Fernand; Lemoufouet, Jules; Kana, Jean R.; Boukila, Benoit; Pamo, E. Tedonkeng; MNM, Bertine

    2015-01-01

    A study on the acaricidal properties of foam soap containing the essential oil of Chenopodium ambrosioides leaves was carried out on Rhipicephalus lunulatus. Four doses (0.03, 0.06, 0.09, and 0.12 µL of essential oil per gram of soap) and a control (soap without essential oil) with four replications for each treatment were used for in vitro trial. Each replication consisted of 10 ticks in a Petri dish with filter paper impregnated with the foam soap on the bottom. Following in vitro trials, three doses (0.06, 0.09, and 0.12 µL/g) and the control in two replications were selected for in vivo test based on mortality rate recorded from the in vitro trial. Each replication was made up of 10 goats naturally infested with ticks. Results show that soap containing essential oil is toxic to R. lunulatus. The in vivo mortality rate in the control on day 8 was 22.69% whereas the highest dose (0.12 µL/g) killed 96.29% of the ticks on day 8. The LD50 of the foam soap containing essential oil was 0.037 and 0.059 µL/g on day 2 in the laboratory and on the farm, respectively. This indicates the potentially high efficiency of this medicated soap on this parasite. PMID:26770829

  13. Performance analysis of LAN bridges and routers

    Science.gov (United States)

    Hajare, Ankur R.

    1991-01-01

    Bridges and routers are used to interconnect Local Area Networks (LANs). The performance of these devices is important since they can become bottlenecks in large multi-segment networks. Performance metrics and test methodology for bridges and routers were not standardized. Performance data reported by vendors is not applicable to the actual scenarios encountered in an operational network. However, vendor-provided data can be used to calibrate models of bridges and routers that, along with other models, yield performance data for a network. Several tools are available for modeling bridges and routers - Network II.5 was used. The results of the analysis of some bridges and routers are presented.

  14. [1,1'-Bis(diphenyl-phosphino)cobalto-cenium-κP,P']dichloridoplatinum(II) hexa-fluorido-phosphate.

    Science.gov (United States)

    Guan, Jin-Tao; Zhang, Kai-Cheng; Dai, Zhi-Qun

    2009-07-22

    The title bimetallic compound, [PtCl(2){Co(C(17)H(14)P)(2)}]PF(6), was obtained by reaction of 1,1'-bis-(diphenyl-phosphino)cobalto-cenium hexa-fluorido-phosphate with bis-(acetonitrile)di-chloridoplatinum. The Pt(II) ion is four-coordinated in a slightly distorted square-planar environment by two P atoms of the 1,1'-bis-(diphenyl-phosphino)cobaltocenium moiety and two Cl atoms. In the crystal structure, mol-ecules are linked by weak C-H⋯F and C-H⋯Cl hydrogen bonds.

  15. Problems associated with nondestructive evaluation of bridges

    Science.gov (United States)

    Prine, David W.

    1995-05-01

    The US has 542,000 bridges that consume billions of dollars per year in construction, rehabilitation, and maintenance funds and which are the lifelines of US commerce. The 1992 ISTEA (Intermodal Surface Transportation Efficiency Act) mandates the implementation of a quantitative computerized bridge management system by 1996. A prime need of such a system are quantitative bridge inspection methods to feed accurate reliable condition information to the huge database of bridges. Nondestructive evaluation (NDE) will fill a critical need in the implementation of effective bridge management. However, many serious barriers exist to the widespread routine application of this technology to bridges. This paper provides an overview of the typical problems associated with applying NDE to bridges.

  16. Ruthenium(III)-catalysed phenylselenylation of allyl acetates by diphenyl diselenide and indium(I) bromide in neat: isolation and identification of intermediate.

    Science.gov (United States)

    Saha, Amit; Ranu, Brindaban C

    2011-03-21

    A fast and efficient phenylselenylation of allyl acetates by diphenyl diselenide and indium(I) bromide has been achieved in neat under the catalysis of Ru(acac)(3). The intermediate complex of diphenyl diselenide and indium has been isolated and identified as a polymeric pentacoordinated In(III) selenolate complex, [In(SePh)(3)](n).

  17. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

    Technical University of Denmark (DTU) and University of Southern Denmark (SDU) have conducted several full-scale experiments with severe ASR deteriorated bridges. This paper presents few and preliminary results from both the shear tests and the measuring of the material properties. The shear test...... show that the shear capacity is almost unaffected of ASR despite significant reduction in compressive concrete strength. Furthermore, measurements show a significant tensile reinforcement strain developed due to ASR expansion....

  18. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  19. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  20. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  1. Cross-Quint-Bridge Resistor

    Science.gov (United States)

    Hannaman, David J.; Lieneweg, Udo; Buehler, Martin G.; Mantalas, Linda

    1991-01-01

    Integrated-circuit conductive test pattern intended to provide data on effects of design widths and design spacings upon actual widths of conductive lines. Provides for electrical measurements both on lines of unknown width and on features having known dimensions. Data from measurements on five bridges used to determine four parameters of mathematical model describing system. In principle, pattern determines effects of width and spacing and interaction between them.

  2. Cochleates bridged by drug molecules.

    Science.gov (United States)

    Syed, Uwais M; Woo, Amy F; Plakogiannis, Fotios; Jin, Tuo; Zhu, Hua

    2008-11-03

    A new type of cochleate, able to microencapsulate water-soluble cationic drugs or peptides into its inter-lipid bi-layer space, was formed through interaction between negatively charged lipids and drugs or peptides acting as the inter-bi-layer bridges instead of multi-cationic metal ions. This new type of cochleate opened up to form large liposomes when treated with EDTA, suggesting that cationic organic molecules can be extracted from these cochleates in a way similar to multivalent metal ions from metal ion-bridged cochleates. Cochleates can be produced in sub-micron size using a method known as "hydrogel isolated cochleation" or simply by increasing the ratio of multivalent cationic peptides over negatively charged liposomes. When nanometer-sized cochleates and liposomes containing the same fluorescent labeled lipid component were incubated with human fibroblasts cells under identical conditions, cells exposed to cochleates showed bright fluorescent cell surfaces, whereas those incubated with liposomes did not. This result suggests that cochleates' edges made them fuse with the cell surfaces as compared to edge free liposomes. This mechanism of cochleates' fusion with cell membrane was supported by a bactericidal activity assay using tobramycin cochleates, which act by inhibiting intracellular ribosomes. Tobramycin bridged cochleates in nanometer size showed improved antibacterial activity than the drug's solution.

  3. Halliburton Composite Bridge Plug Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Starbuck, J.M.; Luttrell, C.R.; Aramayo, G.

    2005-01-15

    The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.

  4. Salt bridges: geometrically specific, designable interactions.

    Science.gov (United States)

    Donald, Jason E; Kulp, Daniel W; DeGrado, William F

    2011-03-01

    Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms.

  5. Synthesis and characterization of alternating poly(amide urethane)s from ε-caprolactone, diamines and diphenyl carbonate

    NARCIS (Netherlands)

    Sharma, Bhaskar; Keul, Helmut; Höcker, Hartwig; Loontjens, Ton; Benthem, Rolf van

    2005-01-01

    The synthesis of alternating poly(amide urethane)s 5a–d was performed in three steps using ε-caprolactone, diamines, and diphenyl carbonate as starting materials. The microstructure and nature of the end groups of the poly(amide urethane)s were determined by means of 1H NMR spectroscopy, which revea

  6. Polybrominated diphenyl ethers from the marine organisms Lendenfeldia dendyi and Sinularia dura with anti-MRSa activity

    Science.gov (United States)

    Bioassay-guided fractionation of the marine sponge Lendenfeldia dendyi and the soft coral Sinularia dura resulted in the isolation of five polybrominated diphenyl ethers (1-5). The structures of the isolated compounds were determined using spectroscopic methods(lD and 2D NMR) and HRMS analyses. The ...

  7. Complexation of Diphenyl(phenylacetenyl)phosphine to Rhodium(III) Tetraphenyl Porphyrins : Synthesis and Structural, Spectroscopic, and Thermodynamic Studies

    NARCIS (Netherlands)

    Stulz, Eugen; Scott, Sonya M.; Bond, Andrew D.; Otto, Sijbren; Sanders, Jeremy K.M.

    2003-01-01

    The coordination of diphenyl(phenylacetenyl)phosphine (DPAP) to (X)RhIIITPP (X = I or Me (3); TPP = tetraphenyl porphyrin) was studied in solution and in the solid state. The iodide is readily displaced by the phosphine, leading to the bis-phosphine complex [(DPAP)2Rh(TPP)](I) (4). The methylide on

  8. Complexation of Diphenyl(phenylacetenyl)phosphine to Rhodium(III) Tetraphenyl Porphyrins : Synthesis and Structural, Spectroscopic, and Thermodynamic Studies

    NARCIS (Netherlands)

    Stulz, Eugen; Scott, Sonya M.; Bond, Andrew D.; Otto, Sijbren; Sanders, Jeremy K.M.

    2003-01-01

    The coordination of diphenyl(phenylacetenyl)phosphine (DPAP) to (X)RhIIITPP (X = I or Me (3); TPP = tetraphenyl porphyrin) was studied in solution and in the solid state. The iodide is readily displaced by the phosphine, leading to the bis-phosphine complex [(DPAP)2Rh(TPP)](I) (4). The methylide on

  9. Comparative absorption and bioaccumulation of polybrominated diphenyl ethers following ingestion via dust and oil in male rats

    Science.gov (United States)

    Household dust has been implicated as a major source of polybrominated diphenyl ether (PBDE) exposure in humans. This finding has important implications especially for young children, who tend to ingest more dust than adults and may be more susceptible to some of the putative developmental effects ...

  10. Improving Infant Exposure and Health Risk Estimates: Using Serum Data to Predict Polybrominated Diphenyl Ether Concentrations in Breast Milk

    Science.gov (United States)

    Women in the United States have breast milk concentrations of polybrominated diphenyl ethers (PBDEs) that are among the highest in the world, leading to concerns over the potential health implications to breastfeeding infants during critical stages of growth and development. Deve...

  11. Monofluorinated analogues of polybrominated diphenyl ethers as analytical standards: Synthesis, NMR, and GC-MS characterization and molecular orbital studies

    NARCIS (Netherlands)

    Luthe, G.; Leonards, P.E.G.; Reijerink, G.S.; Liu, H.L.; Johansen, J.E.; Robertson, L.W.

    2006-01-01

    Polybrominated diphenyl ethers (PBDEs), a group of 209 individual congeners distinguishable by the number and position of bromines,are produced for use as flame retardants in consumer goods. PBDEs have become ubiquitous environmental contaminants, present in increasing levels in the environment and

  12. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Jun Jie Gao; Hui Quan Li; Yi Zhang

    2007-01-01

    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  13. Determination of brominated flame retardants, with emphasis on polybrominated diphenyl ethers (PBDEs) in environmental and human samples - a review

    NARCIS (Netherlands)

    Covaci, A.; Voorspoels, S.; Boer, de J.

    2003-01-01

    Analytical methods for the determination of brominated flame retardants (BFRs), with a special emphasis on polybrominated diphenyl ethers (PBDEs) are reviewed. A number of procedures, which can be applied to the analysis of PBDEs and polybrominated biphenyls (PBBs), and in some cases for

  14. 朱砂叶螨对天然杀螨活性物质东莨菪内酯的抗性评价%The Resistance Evaluation of Tetranychus cinnabarinus against Natural Acaricidal Compound Scopoletin

    Institute of Scientific and Technical Information of China (English)

    张永强; 丁伟; 王丁祯

    2011-01-01

    [目的]通过室内抗药性筛选,比较了朱砂叶螨对植物源杀螨活性物质东莨菪内酯和螺螨酯的抗性发展差异.[结果]在70%的选择压力下,筛选18代,朱砂叶螨对东莨菪内酯的抗性系数基本没有变化.同期,对螺螨酯的抗药性发展速度较快,在相同选择压力下,筛选至14代,抗性系数达18.88.b值分析表明:这一种群中出现了抗性杂合子,而且有增多的趋势.[结论]对进一步研究东莨菪内酯的杀螨作用机理及新型杀螨剂开发具有重要的理论指导意义.%[Aims] The resistance evaluations of botanical acaricidal compounds scopoletin and spirodiclofen were carried out in the laboratory in order to find out their difference. [Results] The results showed that the carmine spider mite exhibited no resistance to scopoletin by 18 generation screening. However, Tetranychus cinnabarinus produced resistance to spirodiclofen quickly, under the same selection pressure of 70% mortality, and by screening of 14 generations, resistance index reached 18.88. Analysis of b value suggested that mixed heterozygotes with resistance appeared in the population, and the number had significant increasing tendency, this is a clear signal of generated resistance. [Conclusions] This result proved theoretical conduction for further study of scopoletin acaricidal mechanism and development of novel acaricides based on scopoletin.

  15. The effects of contact configurations on the rectification of dipyrimidinyl-diphenyl diblock molecular junctions

    Institute of Scientific and Technical Information of China (English)

    Zhang Guang-Ping; Hu Gui-Chao; Li Zong-Liang; Wang Chuan-Kui

    2011-01-01

    The transport properties of a conjugated dipyrimidinyl-diphenyl diblock oligomer sandwiched between two gold electrodes,as recently reported by [Díez-Pérez et al.Nature Chem.1 635 (2009)],are theoretically investigated using the fully self-consistent nonequilibrium Green's function method combined with density functional theory.Two kinds of symmetrical anchoring geometries are considered.Calculated current-voltage curves show that the contact structure has a strong effect on the rectification behaviour of the molecular diode.For the equilateral triangle configuration,pronounced rectification behaviour comparable to the experimental measurement is revealed,and the theoretical analysis indicates that the observed rectification characteristic results from the asymmetric shift of the perturbed molecular energy levels under bias voltage.While for the tetrahedron configuration,both rectification and negative differential conductivity behaviours are observed.The calculated results further prove the close dependence of the transporting characteristics of molecular junctions on contact configuration.

  16. Temperature Dependence of Electron Spin Relaxation of 2,2-diphenyl-1-picrylhydrazyl in Polystyrene

    Science.gov (United States)

    Meyer, Virginia; Eaton, Sandra S.; Eaton, Gareth R.

    2012-01-01

    The electron spin relaxation rates for the stable radical DPPH (2,2-diphenyl-1-picrylhydrazyl) doped into polystyrene were studied by inversion recovery and electron spin echo at X-band and Q-band between 20 and 295 K. At low concentration (340 μM, 0.01%) spin-lattice relaxation was dominated by the Raman process and a local mode. At high concentration (140 mM, 5%) relaxation is orders of magnitude faster than at the lower concentration, and 1/T1 is approximately linearly dependent on temperature. Spin lattice relaxation rates are similar at X-band and Q-band. The temperature dependence of spin echo dephasing was faster at about 140 K than at higher or lower temperatures, which is attributed to a wagging motion of the phenyl groups. PMID:23565040

  17. Chlorido[1-(diphenyl­phosphan­yl)cobaltocenium]gold(I) hexa­fluoridophosphate

    Science.gov (United States)

    Wu, Xiang-Hua

    2011-01-01

    In the cobaltocenium group of the title compound, [AuCo(C5H5)(C17H14P)Cl]PF6, the substituted cyclo­penta­dienyl (Cps) and the unsubstituted cyclo­penta­dienyl (Cp) ring planes are almost parallel, making a dihedral angle of 3.1 (3)°. The C atoms in Cp and Cps are in an eclipsed conformation. The AuI atom is coordinated by a P atom from the diphenyl­phosphanyl group and a Cl atom in an almost linear arrangement [P—Au—Cl = 178.15–(7)°]. Two hexa­fluorido­phosphate anions are each located on a twofold rotation axis. In the crystal, the complex cations and hexa­fluorido­phosphate anions are linked via inter­molecular C—H⋯F hydrogen bonds. PMID:21754675

  18. Chlorido[1-(diphenyl-phosphan-yl)cobaltocenium]gold(I) hexa-fluoridophosphate.

    Science.gov (United States)

    Wu, Xiang-Hua

    2011-06-01

    In the cobaltocenium group of the title compound, [AuCo(C(5)H(5))(C(17)H(14)P)Cl]PF(6), the substituted cyclo-penta-dienyl (Cps) and the unsubstituted cyclo-penta-dienyl (Cp) ring planes are almost parallel, making a dihedral angle of 3.1 (3)°. The C atoms in Cp and Cps are in an eclipsed conformation. The Au(I) atom is coordinated by a P atom from the diphenyl-phosphanyl group and a Cl atom in an almost linear arrangement [P-Au-Cl = 178.15-(7)°]. Two hexa-fluorido-phosphate anions are each located on a twofold rotation axis. In the crystal, the complex cations and hexa-fluorido-phosphate anions are linked via inter-molecular C-H⋯F hydrogen bonds.

  19. Effect of polybrominated diphenyl ether on development of cultured hippocampal neuron

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polybrominated diphenyl ether (PBDE) is a persistently environmental pollutant ubiquitously found in wildlife and humans. Although concern on PBDE's toxic effects is steadily increasing, its action on the central nervous system (CNS) remains largely unknown. To address this issue, the present study examined the development inhibition of PBDE in neurons. The primary cultured hippocampal neurons of rat were exposed to the commercial decabromodiphenyl ether (deca-BDE), and the neurite length, bifurcation, and synapse formation and maturation were evaluated, based on the confocal microscope imaging. The results showed that the development inhibition in neurons occurred at 15 μmol/L, indicating that PBDE is a potent neurotoxicant and it might obviously inhibit the development of cultured neurons.

  20. Effect of polybrominated diphenyl ether on development of cultured hippocampal neuron

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polybrominated diphenyl ether (PBDE) is a persistently environmental pollutant ubiquitously found in wildlife and humans. Although concern on PBDE’s toxic effects is steadily increasing, its action on the central nervous system (CNS) remains largely unknown. To address this issue, the present study ex- amined the development inhibition of PBDE in neurons. The primary cultured hippocampal neurons of rat were exposed to the commercial decabromodiphenyl ether (deca-BDE), and the neurite length, bi- furcation, and synapse formation and maturation were evaluated, based on the confocal microscope imaging. The results showed that the development inhibition in neurons occurred at 15 μmol/L, indi- cating that PBDE is a potent neurotoxicant and it might obviously inhibit the development of cultured neurons.

  1. Predicting the Relative Retention Time (RRT) of Polybrominated Diphenyl Ethers (PBDEs)

    Institute of Scientific and Technical Information of China (English)

    Shu Shen LIU; Yan LIU; Da Qiang YIN; Lian Sheng WANG

    2005-01-01

    Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time (RRT) of polybrominated diphenyl ethers (PBDEs) were predicted. A four-variable regression model (M30) with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom-C= and-C=,-C= and >C=, >C= and >C=,-C= and-Br.

  2. [Determination of diphenyl and o-phenylphenol in agricultural products by GC/MS].

    Science.gov (United States)

    Takahashi, Kunihiko; Horie, Masakazu; Hirose, Yoshihumi

    2008-01-01

    A simple determination method of diphenyl (DP) and o-phenylphenol (OPP) in agricultural products by GC/MS was examined. DP and OPP were extracted with ethyl acetate in the presence of anh. sodium sulfate. After addition of n-butanol, the extract solution was concentrated. Clean-up was achieved by shaking with graphitized bulk carbon (Supelclean ENVI-Carb). Addition of polyethylene glycol sharpened the OPP peak on GC/MS analysis. The recoveries from 9 kinds of agricultural products spiked at 0.01 and 0.5 microg/g each were mostly in the range of 70 to 120%, except for 50% recovery of OPP from barley spiked at 0.01 microg/g. The quantification limits (S/N > or =10) of DP and OPP were 0.0013 and 0.005 microg/g (0.0025 and 0.01 microg/g in barley and soybean), respectively.

  3. Occurrence of polybrominated diphenyl ethers (PBDEs) in foodstuffs in Italy and implications for human exposure.

    Science.gov (United States)

    Martellini, Tania; Diletti, Gianfranco; Scortichini, Giampiero; Lolini, Meri; Lanciotti, Eudes; Katsoyiannis, Athanasios; Cincinelli, Alessandra

    2016-03-01

    Polybrominated diphenyl ethers (PBDEs) were determined in various foodstuffs in Italy and the dietary intake was estimated. PBDEs were detected in all analysed samples at concentrations that spanned over five orders of magnitude. The most abundant congeners were the BDE-209, followed by BDE-47 and BDE-99. Fish oil and milk samples showed the highest PBDE concentrations among all samples. The daily dietary intake values were found to be in good agreement or higher to literature values, impacted mainly from the contribution of the analysed dairy products. The cancer risk values estimated for BDE-209 indicated that this specific risk associated with the studied foodstuffs is limited. Italy is one of the world-leading countries in the production of furniture and clothes and has extremely developed medium enterprise industrial sector, where PBDEs were historically used suggesting that their occurrence may be linked to these activities.

  4. Potential of groundwater contamination by polybrominated diphenyl ethers (PBDEs) in a sensitive bedrock aquifer (Canada)

    Science.gov (United States)

    Levison, Jana; Novakowski, Kent; Reiner, Eric J.; Kolic, Terry

    2012-03-01

    It is necessary to understand the presence, movement, and persistence of contaminants in aquifers to develop adequate groundwater protection plans. Fractured bedrock aquifers with thin overburden cover are very sensitive to contamination, and little is known about transport processes from the ground surface to depth in this setting. This study was undertaken to investigate the potential of groundwater contamination by polybrominated diphenyl ethers (PBDEs), which are flame retardants, in a natural fractured bedrock aquifer in Canada proven to be sensitive to contamination. PBDEs, which had not been previously measured in groundwater in detail, were detected in the study aquifer at concentrations greater than those observed in surface-water bodies. Potential sources include manure, septic tanks, and the atmosphere. From this scoping study, it is evident that additional surveys of PBDE concentrations in groundwater are warranted, especially in settings with high potential source concentrations coupled with sensitive aquifers.

  5. The Sequestration of Oxy-Polybrominated Diphenyl Ethers in the Nudibranchs Miamira magnifica and Miamira miamirana

    Directory of Open Access Journals (Sweden)

    Ariyanti S. Dewi

    2016-10-01

    Full Text Available A series of oxy-polybrominated diphenyl ethers (O-PBDEs has been isolated from the extracts of Miamira magnifica and Miamira miamirana collected from Queensland, Australia. M. magnifica sequesters the new OH-PBDE 1 and six known OH-PBDEs containing four to six bromines (2–7. M. miamirana also accumulates known tribromo- and tetrabromo OMe-PBDEs 8–10 in both mantle and viscera tissues. To date, Miamira is the only genus of the family Chromodorididae that is known to incorporate O-PBDEs, rather than terpenes, in the mantle where the metabolites may play a putative role in chemical defense. The extract of M. magnifica was tested in a brine shrimp lethality assay and exhibited an LD50 of 58 μg/mL.

  6. trans-Carbonylchloridobis[diphenyl(4-vinylphenylphosphane-κP]rhodium(I

    Directory of Open Access Journals (Sweden)

    Reinout Meijboom

    2012-05-01

    Full Text Available In the title compound, trans-[RhCl(C20H17P2(CO], the RhI atom is situated on a center of symmetry, resulting in a statistical 1:1 disorder of the chloride [Rh—Cl = 2.383 (2 Å] and carbonyl [Rh—C = 1.752 (7 Å] ligands. The distorted trans square-planar environment is completed by two P atoms [Rh—P = 2.3251 (4 Å] from two diphenyl(4-vinylphenylphosphane ligands. The vinyl group is disordered over two sets of sites in a 0.668 (10:0.332 (10 ratio. The crystal packing exhibits weak C—H...Cl and C—H...O hydrogen bonds and π–π interactions between the phenyl rings of neighbouring molecules, with a centroid–centroid distance of 3.682 (2 Å.

  7. Solvent extraction of trivalent lanthanoid ions with N,N`-dimethyl-N,N`-diphenyl-3-oxapentanediamide

    Energy Technology Data Exchange (ETDEWEB)

    Narita, H.; Tachimori, S. [Separation Chemistry Lab., Japan Atomic Energy Research Inst., Ibaraki (Japan)]|[Ibaraki Univ., Bunkyo (Japan); Yaita, T.; Tamura, K. [Ibaraki Univ., Bunkyo (Japan)

    1998-12-31

    The extraction of trivalent lanthanoid ions from nitric acid and hydrochloric acid solutions by N,N`-dimethyl-N,N`-diphenyl-3-oxapentanediamide, DMDPhOPDA, was investigated. The distribution ratios in the nitric acid system were much higher than those in the hydrochloric acid system. In the nitric acid system, the dependencies of the distribution ratios on nitric acid and DMDPhOPDA concentrations showed a difference between lighter and heavier lanthanoid ions. The plots of the number of DMDPhOPDA molecules in the extracted species obtained from slope analysis in 4 mol dm{sup -3} nitric acid versus the ionic radius of trivalent lanthanoid ions exhibited a significant change around the middle of the lanthanoids (S-shape). The distribution ratios in the nitric acid system increased with an increase in the atomic number, while those in the HCl system decreased. (orig.)

  8. Interaction of Polybrominated Diphenyl Ethers and Aerobic Granular Sludge: Biosorption and Microbial Degradation

    Directory of Open Access Journals (Sweden)

    Shou-Qing Ni

    2014-01-01

    Full Text Available As a new category of persistent organic pollutants, polybrominated diphenyl ethers (PBDEs have become ubiquitous global environmental contaminants. No literature is available on the aerobic biotransformation of decabromodiphenyl ether (BDE-209. Herein, we investigated the interaction of PBDEs with aerobic granular sludge. The results show that the removal of BDE-209 from wastewater is mainly via biosorption onto aerobic granular sludge. The uptake capacity increased when temperature, contact time, and sludge dosage increased or solution pH dropped. Ionic strength had a negative influence on BDE-209 adsorption. The modified pseudo first-order kinetic model was appropriate to describe the adsorption kinetics. Microbial debromination of BDE-209 did not occur during the first 30 days of operation. Further study found that aerobic microbial degradation of 4,4′-dibromodiphenyl ether happened with the production of lower BDE congeners.

  9. Removal rate and releases of polybrominated diphenyl ethers in two wastewater treatment plants, Korea

    Science.gov (United States)

    Lee, Hyo Jin; Kim, Gi Beum

    2017-06-01

    Wastewater treatment plants (WWTPs) play an important role in minimizing the release of many pollutants into the environment. Nineteen congeners in two WWTPs in Korea were determined to investigate the occurrence and fate of polybrominated diphenyl ethers (PBDEs) during wastewater treatment processes. The concentration of total PBDEs was 69.6 and 183 ng/L in influent, which declined to 1.59 and 2.34 ng/L in the final effluent, respectively (Tongyeong and Jinhae WWTPs). PBDEs were found to exist mostly in the particulate phase of wastewater, which rendered sedimentation efficient for the removal of PBDEs. BDE-209 was the predominant congener in the influent and sludge. Most of the PBDEs entering the WWTPs presumably ended up in the sludge, with WWTP in Korea.

  10. Polybrominated diphenyl ethers in mussels (Mytilus galloprovincialis) collected from Central Adriatic Sea.

    Science.gov (United States)

    Piersanti, Arianna; Tavoloni, Tamara; Bastari, Eleonora; Lestingi, Carmela; Romanelli, Sara; Saluti, Giorgio; Moretti, Simone; Galarini, Roberta

    2015-12-15

    One-hundred and thirty-four samples of mussels (Mytilus galloprovincialis) collected along Central Adriatic Sea in 2013 were examined to determine the levels of fifteen congeners of polybrominated diphenyl ethers (PBDEs). The purified samples were analysed by gas-chromatography coupled to tandem mass spectrometry (GC-MS/MS) applying the isotopic dilution. Only four congeners (PBDE 47, PBDE 99, PBDE 49 and PBDE 100) were present above the established limits of quantification with mean concentrations equal to 73, 30, 19 and 18 pg g(-1), respectively. The concentrations of PBDEs (sum) ranged from 27 to 386 pg g(-1), with the highest levels around the coastal area of Ancona town. The here found levels were comparable to those measured in mussels collected along Southern Adriatic Sea.

  11. Synthesis and in vitro evaluation of new diphenyl ether derivatives as serotonin transporter ligands

    Institute of Scientific and Technical Information of China (English)

    DEUTHER-CONRAD; Winnie; BRUST; Peter; STEINBACH; Jrg; VERCOUILLIE; Johnny

    2008-01-01

    For the development of new ligands as potential imaging agents for the serotonin transporter (SERT),a series of diphenyl ether derivatives have been synthesized,characterized,and evaluated for their in vitro binding affinities to the SERT. Among the above compounds,2-(2-((dimethylamino)methyl)-4-fluoro-phenoxy)-5-bromobenzenamine (15) and 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-iodobenzene amine (16) show high binding affinities for the SERT with Ki values of 0.28 and 0.20 nmol·L-1,respectively. They can be further labeled with carbon-11,fluorine-18,iodine-123 or bromine-76,and evaluated as useful imaging agents for the SERT. Moreover,the study of the structure-activity relationship (SAR) provides some useful information for the future design of new ligands.

  12. Evaluating daily exposure to polychlorinated biphenyls and polybrominated diphenyl ethers in fish oil supplements.

    Science.gov (United States)

    Ashley, J T F; Ward, J S; Schafer, M W; Stapleton, H M; Velinsky, D J

    2010-08-01

    Fish oil supplements have become a popular means of increasing one's dietary intake of essential polyunsaturated fatty acids. However, there is growing concern that the levels and potential health effects of lipophilic organic contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may diminish some of the health benefits associated with the daily consumption of fish oil supplements. In this study, ten over-the-counter fish oil supplements available in the United States were analysed for PCBs and PBDEs and daily exposures calculated. Based on manufacturers' recommended dosages, daily intakes of PCBs and PBDEs ranged from 5 to 686 ng day(-1) and from 1 to 13 ng day(-1), respectively. Daily consumption of fish oil supplements expose consumers to PCBs and PBDEs. However, in comparison with fish ingestion, fish supplements may decrease daily PCB exposure and provide a safer pathway for individuals seeking to maintain daily recommended levels of polyunsaturated fatty acids.

  13. Assessment of the levels of polybrominated diphenyl ethers in blood samples from Guadalajara, Jalisco, Mexico.

    Science.gov (United States)

    Orta-Garcia, Sandra Teresa; León-Moreno, Lilia Carolina; González-Vega, Carolina; Dominguez-Cortinas, Gabriela; Espinosa-Reyes, Guillermo; Pérez-Maldonado, Iván N

    2012-10-01

    The purpose of this study was to measure levels of polybrominated diphenyl ethers (PBDEs) in the blood of children (50 individuals) living in Guadalajara, Jalisco, Mexico. We analyzed six PBDE congeners by gas chromatography-mass spectrometry. Total PBDE levels ranged from not detectable (nd) to 15.2 μg/L on a whole-weight basis and from nd to 6,435 ng/g lipid on a lipid-weight basis. The dominant congener in our study was BDE-153, followed by BDE-154, BDE-99, BDE-100, and BDE-47. Levels of BDE-209 were below the detection limit. Our data indicate that children living in the areas studied in this work are exposed to high levels of PBDEs.

  14. Rational design and synthesis of novel diphenyl ether derivatives as antitubercular agents.

    Science.gov (United States)

    Kar, Sidhartha S; Bhat G, Varadaraj; Rao, Praveen Pn; Shenoy, Vishnu P; Bairy, Indira; Shenoy, G Gautham

    2016-01-01

    A series of triclosan mimic diphenyl ether derivatives have been synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. The binding mode of the compounds at the active site of enoyl-acyl carrier protein reductase of M. tuberculosis has been explored. Among them, compound 10b was found to possess antitubercular activity (minimum inhibitory concentration =12.5 µg/mL) comparable to triclosan. All the synthesized compounds exhibited low levels of cytotoxicity against Vero and HepG2 cell lines, and three compounds 10a, 10b, and 10c had a selectivity index more than 10. Compound 10b was also evaluated for log P, pKa, human liver microsomal stability, and % protein binding, in order to probe its druglikeness. Based on the antitubercular activity and druglikeness profile, it may be concluded that compound 10b could be a lead for future development of antitubercular drugs.

  15. Rational design and synthesis of novel diphenyl ether derivatives as antitubercular agents

    Science.gov (United States)

    Kar, Sidhartha S; Bhat G, Varadaraj; Rao, Praveen PN; Shenoy, Vishnu P; Bairy, Indira; Shenoy, G Gautham

    2016-01-01

    A series of triclosan mimic diphenyl ether derivatives have been synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. The binding mode of the compounds at the active site of enoyl-acyl carrier protein reductase of M. tuberculosis has been explored. Among them, compound 10b was found to possess antitubercular activity (minimum inhibitory concentration =12.5 µg/mL) comparable to triclosan. All the synthesized compounds exhibited low levels of cytotoxicity against Vero and HepG2 cell lines, and three compounds 10a, 10b, and 10c had a selectivity index more than 10. Compound 10b was also evaluated for log P, pKa, human liver microsomal stability, and % protein binding, in order to probe its druglikeness. Based on the antitubercular activity and druglikeness profile, it may be concluded that compound 10b could be a lead for future development of antitubercular drugs. PMID:27486307

  16. Preparation and Property of Bisphenol A Bis(diphenyl phosphate) Oligomer

    Institute of Scientific and Technical Information of China (English)

    LI Bing-hai; OU Yu-xiang; XIN Fei

    2007-01-01

    Bisphenol A bis(diphenyl phosphate) oligomer(BDP) is prepared successfully from the reactants consisting of phosphorus oxychloride (POCl3), bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermo-gravimetric analysis (TGA) and high performance liquid chromatography(HPLC). Thermogravimetry data shows that BDP decomposes at 375℃ when 5% weight lost. Experiments results show that catalyst is preferably AlCl3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5∶1 to 6∶1. Experiments unclosed that a seal apparatus is very important to the properties of product.

  17. SYNTHESIS AND POLYMERIZATION OF 2-OXO-3-METHYLENE-5,6-DIPHENYL-1,4-DIOXAN

    Institute of Scientific and Technical Information of China (English)

    FENG Pinzhen; LU Jiantao

    1994-01-01

    A new cyclic monomer, 2-oxo-3-methylene-5, 6-diphenyl-1,4-dioxan, was synthesized. The structure of the intermediates and the monomer were determined by IR,1H NMR,13C NMR and elemental analysis. This new monomer is different from other cyclic monomers in this series,it is a solid (mp 108-109℃)and not very reactive,but still can undergo free radical ring-opening polymerization. The free radical polymerization was carried out at 130℃. The structure of the resulting polymer was discussed and charaterized by IR, 1H NMR, 13C NMR and elemental analysis. The molecular weight of the polymer was estimated by viscosity determination.

  18. Current levels of primary polybrominated diphenyl ethers (PBDEs) in Norwegian seafood

    Energy Technology Data Exchange (ETDEWEB)

    Bethune, C.; Nielsen, J.; Julshamn, K. [National Institute of Nutrition and Seafood Research, Bergen (Norway)

    2004-09-15

    The brominated flame retardants (BFRs) represent major industrial chemicals whose use has increased dramatically over the past few decades. Polybrominated diphenyl ethers (PBDEs) are BFRs that are used in many types of consumer products. PBDEs have come to the attention of regulators and scientists due to their bioaccumulation, increasing exposure and persistence in the environment, and adverse health effects in animals and humans. Although PBDE contamination in marine fish was first detected in Sweden in 1979, and certain PBDEs are now banned as of this year, the European Union has yet to establish regulations on PBDE levels in either feed or seafood. The determination of these contaminants in consumer seafood is important for dietary exposure assessment and protection of human health. This study reports on the levels of 6 prominent PBDE congeners (28, 47, 99, 100, 153, and 154) in a selection of common Norwegian seafood.

  19. AQUATOX coupled foodweb model for ecosystem risk assessment of Polybrominated diphenyl ethers (PBDEs) in lake ecosystems.

    Science.gov (United States)

    Zhang, Lulu; Liu, Jingling

    2014-08-01

    The AQUATOX model considers the direct toxic effects of chemicals and their indirect effects through foodwebs. For this study, the AQUATOX model was applied to evaluating the ecological risk of Polybrominated diphenyl ethers (PBDEs) in a highly anthropogenically disturbed lake-Baiyangdian Lake. Calibration and validation results indicated that the model can adequately describe the dynamics of 18 biological populations. Sensitivity analysis results suggested that the model is highly sensitive to temperature limitation. PBDEs risk estimate results demonstrate that estimated risk for natural ecosystems cannot be fully explained by single species toxicity data alone. The AQUATOX model could provide a good basis in ascertaining ecological protection levels of "chemicals of concern" for aquatic ecosystems. Therefore, AQUATOX can potentially be used to provide necessary information corresponding to early warning and rapid forecasting of pollutant transport and fate in the management of chemicals that put aquatic ecosystems at risk. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Lactational Exposure to Polybrominated Diphenyl Ethers and Its Relation to Early Childhood Anthropometric Measurements.

    Science.gov (United States)

    Hoffman, Kate; Mendez, Michelle; Siega-Riz, Anna Maria; Herring, Amy H; Sjödin, Andreas; Daniels, Julie L

    2016-10-01

    Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants that may influence growth and development. We investigated the association between exposure to PBDEs via breast milk and anthropometric measurements in early childhood. The Pregnancy Infection and Nutrition (PIN) Babies studies followed a cohort of North Carolina pregnant women and their children through 36 months of age. Breast milk samples obtained at 3 months postpartum were analyzed for PBDEs. We collected height and weight records from well-baby doctor visits and also measured children during study visits (n = 246 children with > 1,400 anthropometric measurements). We assessed the relationship between breast milk concentrations of five PBDE congeners-BDEs 28, 47, 99, 100, and 153-and child's weight-for-age, height-for-age, and weight-for-height z-scores (WAZ, HAZ, and WHZ, respectively), adjusting for age; maternal age, race, prepregnancy BMI; parity; smoking during pregnancy; and breastfeeding, and stratifying by sex. Overall, PBDE exposures via breast milk were not associated with early-life anthropometric measures in the PIN Babies cohort. When stratified by sex, PBDEs in milk were inversely associated with WHZ for boys; however, associations did not follow a consistent pattern across the concentration gradient and were imprecisely estimated. Among girls, PBDEs tended to be associated with increased WHZ except for BDE-153, which was inversely associated with WHZ, though all estimates were imprecisely estimated. We observed little evidence of associations between early-life PBDE exposures via breast milk and anthropometric measurements overall; however, our results prompt the need for sex-specific investigations in larger cohorts. Hoffman K, Mendez M, Siega-Riz AM, Herring AH, Sjödin A, Daniels JL. 2016. Lactational exposure to polybrominated diphenyl ethers and its relation to early childhood anthropometric measurements. Environ Health Perspect 124:1656-1661;

  1. Global assessment of polybrominated diphenyl ethers in farmed and wild salmom

    Energy Technology Data Exchange (ETDEWEB)

    Hites, R. [Indiana Univ., Bloomington, IN (United States); Foran, J. [Midwest Center for Environmental Science, Milwaukee, WI (United States); Schwager, S.; Knuth, B. [Cornell Univ., Ithaca, NY (United States); Hamilton, C. [AXYS Analytical, Sydney (Australia); Carpenter, D. [Albany Univ., NY (United States)

    2004-09-15

    Despite their societal benefits, polybrominated diphenyl ethers (PBDEs) seem to be migrating from the products in which they are used and entering the environment and people. PBDEs are now ubiquitous; they can be found in air, water, fish, birds, marine mammals, and people, and in most cases, the concentrations of these compounds have increased dramatically over the last 20 years. One source of PBDEs in people is their food supply, and an increasingly important food is salmon, which is nutritious and high in beneficial fats. Between 1987 and 1999, salmon consumption increased annually at a rate of 10-20%. Currently, over half the salmon sold globally is farm-raised in Northern Europe, Chile, Canada, and the United States, and the annual global production of farmed salmon (predominantly Atlantic salmon) has risen from {proportional_to}27,000 to over 1 million metric tons during the past two decades. The health benefits of eating fish such as salmon have been well documented. However, salmon are relatively fatty, carnivorous fish that feed high in the food web, and as such, they bioaccumulate contaminants. In a previous study, we reported that levels of persistent, bioaccumulative contaminants (such as PCBs, dioxins, and several chlorinated pesticides) are significantly higher in farm-raised salmon than in wild salmon and that salmon raised on European farms have significantly greater toxic contaminant loads than those raised on North and South American farms. In this report, we provide results on polybrominated diphenyl ether concentrations in salmon purchased from farms in eight major salmon farming regions, in five species of wild Pacific salmon, and in salmon fillets purchased at supermarkets in North America and Europe.

  2. Improved debromination of polybrominated diphenyl ethers by bimetallic iron-silver nanoparticles coupled with microwave energy

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Si [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Yang, Shaogui, E-mail: yangdlut@126.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Sun, Cheng, E-mail: envidean@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Gu, Ji-Dong [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2012-07-01

    This study focused on the enhanced debromination of decabromodiphenyl ether (BDE-209) and 2,2 Prime ,4,4 Prime -tetrabromodiphenyl ether (BDE-47) by Fe-Ag nano-particles under microwave radiation (Fe-Ag/MW). Fe-Ag bimetallic nano-particles were synthesized by reductive deposition of Ag on nano-iron and characterized with a number of techniques, including BET, XRD, TEM and XPS. Approximately 97% of BDE-209 or 78% of BDE-47 were rapidly transformed to its degradation products within 8 min in the Fe-Ag/MW system. The dehalogenation efficiency of polybrominated diphenyl ethers (PBDEs) was enhanced apparently by microwave radiation. Moreover, the microwave thermal energy played a significant role in accelerating the degradation reactions. Compared with nano-iron alone, the deposition of Ag also increased the rates of degradation. GC-MS and LC-MS/MS analyses of PBDEs' degradation products reveals that the possible degradation pathway proceeds through stepwise debromination from [n]-bromo- to [n-1]-bromo-DE, with bromine being substituted by hydrogen sequentially. Di- to nona-brominated congeners were formed during BDE-209 reduction, while diphenyl ether to tri-BDEs were observed during BDE-47 degradation. These results suggest that PBDEs can be debrominated rapidly by the innovative processes that may be environmentally friendly in applications. - Highlights: Black-Right-Pointing-Pointer The Fe-Ag nanoparticles with a core-shell structure were successfully prepared. Black-Right-Pointing-Pointer A highly efficient technology for debromination of PBDEs by Fe-Ag/MW was investigated. Black-Right-Pointing-Pointer The effect of bromine's number on the stability against reduction of PBDEs was explored. Black-Right-Pointing-Pointer The role of MW energy and Ag in the reactivity of the Fe-Ag/MW system was demonstrated. Black-Right-Pointing-Pointer The possible degradation pathways of BDE-209 and BDE-47 were proposed.

  3. Evaluation method research on prestressed concrete bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Qiao; LIN Yang-zi; REN Yuan

    2008-01-01

    Considering the construction features of prestressed concrete bridge, the comprehensive evaluation method about the bridge damage conditions are studied. Particular attentions are paid on establishing a multi-level evaluation model for damaged prestressed concrete bridge, and the evaluation indices of the model as well as the rating standards are defined in the model. A normal relative function about the evaluation indices of each element is developed to calculate the relative degree, and for each element which is no sub-level elements. When evaluating the elements in sub-item level or index level of the model, the weights of elements that are pertained to one element are adopted, taking account of their deterioration degree. At the same time, the dam-age conditions of bridge are characterized by relative degree, element evaluation scale and structural technology mark of bridge ,so it agrees with Code for Maintenance of Highway Bridges and Culvers.

  4. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  5. 新颖杀螨剂Pyflubumide的合成和作用机制%The Synthesis and Mode of Action of Novel Acaricide Pyflubumidera

    Institute of Scientific and Technical Information of China (English)

    邓建玲

    2015-01-01

    Pyflubumide是新颖的杀螨剂,具有独特的化学结构,其苯胺部分上有甲氧基取代的六氟异丙基基团.其结构与琥珀酸脱氢酶抑制剂型杀菌剂相似.主要介绍了pyflubumide的发现过程、合成和构效关系;以及作用机制.Pyflubumide在蛛螨体内很快脱酰代谢为NH-物,后者与腈吡螨酯的OH-物作用于线粒体复合体Ⅱ的同一酶,但其结合点和/或结合方式不同,应属于不同的类别.%Pyflubumide is a novel acaricide with a unique chemical structure that contains a methoxy-substituted hexafluoroisopropyl group on the anilino moiety. Its structure is similar to that of succinate-dehydrogenase inhibitor(SDHI) fungicides. This paper introduces the discovery, synthesis and structure-activity relationship of pyflubumide, and its mode of action. Pyflubumide is quickly metabolized to its NH-form in the homogenate of spider mites and NH-form acts on the same enzyme with OH-form of cyenopyrafen. But the two compounds act the different binding sites on mitochondrial complexⅡand/or with the different manners of binding, and should be classified into different groups in terms of their mode of action.

  6. Sperm viability and gene expression in honey bee queens (Apis mellifera) following exposure to the neonicotinoid insecticide imidacloprid and the organophosphate acaricide coumaphos.

    Science.gov (United States)

    Chaimanee, Veeranan; Evans, Jay D; Chen, Yanping; Jackson, Caitlin; Pettis, Jeffery S

    2016-06-01

    Honey bee population declines are of global concern. Numerous factors appear to cause these declines including parasites, pathogens, malnutrition and pesticides. Residues of the organophosphate acaricide coumaphos and the neonicotinoid insecticide imidacloprid, widely used to combat Varroa mites and for crop protection in agriculture, respectively, have been detected in wax, pollen and comb samples. Here, we assess the effects of these compounds at different doses on the viability of sperm stored in the honey bee queens' spermatheca. Our results demonstrate that sub-lethal doses of imidacloprid (0.02ppm) decreased sperm viability by 50%, 7days after treatment. Sperm viability was a downward trend (about 33%) in queens treated with high doses of coumaphos (100ppm), but there was not significant difference. The expression of genes that are involved in development, immune responses and detoxification in honey bee queens and workers exposed to chemicals was measured by qPCR analysis. The data showed that expression levels of specific genes were triggered 1day after treatment. The expression levels of P450 subfamily genes, CYP306A1, CYP4G11 and CYP6AS14 were decreased in honey bee queens treated with low doses of coumaphos (5ppm) and imidacloprid (0.02ppm). Moreover, these two compounds suppressed the expression of genes related to antioxidation, immunity and development in queens at day 1. Up-regulation of antioxidants by these compounds in worker bees was observed at day 1. Coumaphos also caused a repression of CYP306A1 and CYP4G11 in workers. Antioxidants appear to prevent chemical damage to honey bees. We also found that DWV replication increased in workers treated with imidacloprid. This research clearly demonstrates that chemical exposure can affect sperm viability in queen honey bees. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Thermal bridges - calculations, thermal bridge values and impact on energy consumption; Kuldebroer - Beregning, kuldebroverdier og innvirkning paa energibruk

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, Arild; Thue, Jan Vincent; Blom, Peter; Dalehaug, Arvid; Aurlien, Tormod; Grynning, Steinar; Uvsloekk, Sivert

    2008-07-01

    This report presents the following: Definition of thermal bridge; Possible consequences of thermal bridges; Methods to decide thermal bridge value, inclusive by numerical calculation; Thermal bridge values for different constructions; A proposal for dynamic Thermal bridge atlas. The project report shows thermal bridge values for different constructions such as window insertion, transition between wall/ceiling, wall/floor, corners and ridge. Thermal bridge values for different kind of floor such as concrete, LECA and hollow core. (AG). refs., figs., tabs

  8. Mathematical Modelling of Bridges with SAP2000

    OpenAIRE

    Maraž, Miha

    2006-01-01

    The present work describes a relatively new programme module, which is enhanced in the recently released versions of SAP2000 software. The new module, called Bridge Modeler, is intended for simple, parametric mathematical modelling of bridges. The modelling procedure is explained on a test case through the steps of a user-friendly Bridge Wizard. For each step, we described the basic principles and the application possibilities as well as some limitations. We also explained two types of analys...

  9. Bridge Engineering-Oriented Parametric Model

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2004-01-01

    A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

  10. Industrial steel hall with bridge grane

    OpenAIRE

    Jurejevčič, Nejc

    2016-01-01

    In introduction this diploma thesis describes all main characteristics of (single block)? industrial steel hall with bridge crane. Load arrangement on the supporting structure which covers general actions (snow load and wind action), self-weight and dynamic load of bridge crane was designed with moment resisting frame in transverse direction and frame with concentric diagonal bracing in longitudinual direction. Actions induced by crane bridge was considered in design of runway beam. Steel hal...

  11. Bridge engineering handbook construction and maintenance

    CERN Document Server

    Chen, Wai-Fah

    2014-01-01

    Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection highlights bridge engineering specimens from around the world, contains detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject.Published in five books: Fundamentals, Superstructure Design, Substructure Design, Seismic Design, and Construction and Maintenance, this new edition provides numerous worked-out examples that give readers step-by-step design procedures, includes c

  12. Dynamics and Statics of Nonaxisymmetric Liquid Bridges

    Science.gov (United States)

    Alexander, J. Iwan D.; Resnick, Andrew H.; Slobozhanin, L. A.

    1996-01-01

    Theoretical and experimental investigation of the stability of nonaxisymmetric and nonaxisymmetric bridges contained between equal and unequal radii disks as a function of Bond and Weber number with emphasis on the transition from unstable axisymmetric to stable nonaxisymmetric shapes, are conducted. Numerical analysis of the stability of nonaxisymmetric bridges between unequal disks for various orientations of the gravity vector is performed. Experimental and theoretical investigation of large (nonaxisymmetric) oscillations and breaking of liquid bridges are also conducted.

  13. Analysis of liquid bridge between spherical particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonian fluid is often encountered in pariculate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.

  14. Ação fungicida do acaricida azocyclotin sobre a antracnose do feijoeiro comum Fungicidal action of azocyclotin acaricide on comon bean anthracnose

    Directory of Open Access Journals (Sweden)

    Ademir Santini

    2005-01-01

    ao trifenil hidróxido de estanho.The control effect of azocyclotin acaricide was tested to common bean anthracnose pathogen, Colletotrichum lindemuthianum, in vitro, seedlings and in field conditions. The treatments in vitro were: 1 Test; 2 Azocyclotin (AZ- 1 AZ-1 mg.L-1; 3 Triphenil sthanic hydroxide (THE-1 mg L-1; 4 AZ-10 mg L-1; 5 THE-10 mg L-1; 6 AZ-100 mg L-1 and 7 THE-100 mg L-1 and in vivo treatments were: 1 Test; 2 AZ applyed 24 hours before inoculation (AZ-24; 3THE-24; 4 AZ-48; 5THE-48; 6 AZ-72; 7 THE-72; 8 AZ-96; 9 THE-96; 10 AZ-120; 11 THE-120; 12 AZ-144, and 13 THE-144. Azocyclotin was evaluated at 125 g.100 L-1 of water and fenthin hydroxide at 41,25 g a.i.100 L-1. The experiments were set up as a completely randomized design, with 5 repetitions. In field conditions, the treatments (g ha-1 a.i. included: 1 tebuconazole + fentin hydroxide-100 + 200; 2 tebuconazole + trifloxystrobin-40 + 100; 3 trifloxystrobin-125; 4 tebuconazole + azocyclotin-100 + 500; 5 azocyclotin - 500 and 6 without chemical. The experimental design was done using randomized blocks, with 4 replicates. The mycelial growth was determined through reading the fungi radial growth in BDA culture media. In vivo and in field conditions, evaluations were made with a scale of 1 to 9, where 1 = without symptoms and 9 = equal or more than 25% of foliar area with anthracnose symptoms. In vitro test, the treatment 7 presented the most effective mycelial development inhibition. Azocyclotin and triphenil sthanic hydroxide controlled dry bean anthracnose when applied until 144 hours before inoculation. A new field record was the control of bean anthracnose with azocyclotin acaricide, with effect on both to angular leaf spot and alternaria leaf spot. It was concluded that azocyclotin acaricide can control dry bean anthracnose with similar efficiency as fentin hydroxide.

  15. Nanoclusters a bridge across disciplines

    CERN Document Server

    Jena, Purusottam

    2010-01-01

    This comprehensive book on Nanoclusters comprises sixteen authoritative chapters written by leading researchers in the field. It provides insight into topics that are currently at the cutting edge of cluster science, with the main focus on metal and metal compound systems that are of particular interest in materials science, and also on aspects related to biology and medicine. While there are numerous books on clusters, the focus on clusters as a bridge across disciplines sets this book apart from others. Delivers cutting edge coverage of cluster science Covers a broad range of topics in

  16. Buddha and the bridging relations.

    Science.gov (United States)

    Banerjee, Rahul

    2008-01-01

    The chapter reviews a classical Indian model of consciousness found in the Abhidhamma, a collection of seven treatises in the Pali Canon Tipitaka. The model was based on observations made during advanced vipassana practice, a first-person method taught by the Buddha. The climax of the model consists in the elucidation of 24 'Bridging Relations' causally linking the stream of consciousness, its contents and associated physical events. Review of such a model based on a specialized first-person technique could prove to be a resource of useful ideas providing directions for further research.

  17. Family Medicine: Bridge to Life.

    Science.gov (United States)

    Luz, Clare

    2016-01-01

    Reflecting on the suicide of a close friend, this essay explores what comprises, and inspires a will to live, and how those in Family Medicine can address suicide risk even in the face of debilitating or terminal illness. Research indicates that the will to live is a measurable indicator of general well-being, distinct from depression, and an important predictor of a person's motivation to "hold on to life". As such, understanding what is at the heart of a desire to live should alter clinical practice. This essay offers ideas for ways in which to create bridges for patients that could help sustain life.

  18. A bridge to advanced mathematics

    CERN Document Server

    Sentilles, Dennis

    2011-01-01

    This helpful workbook-style ""bridge"" book introduces students to the foundations of advanced mathematics, spanning the gap between a practically oriented calculus sequence and subsequent courses in algebra and analysis with a more theoretical slant. Part 1 focuses on logic and number systems, providing the most basic tools, examples, and motivation for the manner, method, and concerns of higher mathematics. Part 2 covers sets, relations, functions, infinite sets, and mathematical proofs and reasoning. Author Dennis Sentilles also discusses the history and development of mathematics as well a

  19. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  20. CONDITION RATING SYSTEM FOR THAILAND'S CONCRETE BRIDGES

    Directory of Open Access Journals (Sweden)

    Bonaventure H.W. Hadikusumo

    2010-06-01

    Full Text Available The Bridge Management System is designed to maximise use of available data and determine the optimal strategy to perform necessary improvements to bridges in the most cost-effective manner. This paper provides a condition rating system to meet the requirements of Thailand’s Department of Highways (DOH. A rating system to assess the existing condition of bridges is proposed. Segmental inspection is developed to execute efficient element-level evaluations and collect data that demonstrate deterioration patterns in bridge elements. The paper also describes inspection procedures for field survey execution, which enables observed distresses at the level of sub-elements or members to be allocated. Recommendations from bridge experts reveal that the proposed rating system is robust, implementable in actual practice, and suitable for efficient application in evaluating the nation’s concrete highway bridges. Although the bridge condition rating was developed in response to the specific characteristics of Thailand’s bridges, the proposed methodology can easily be extended to other bridge agencies.

  1. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

    Middleton, C. R.; Thoft-Christensen, Palle

    a significant shift in emphasis for the highways authorities around the world away from the design of new structures over to maintaining the existing infrastructure. As a result, bridge owners are seeking improved ways of inspecting, assessing, maintaining and repairing their existing stock of bridges...... in the wake of ever increasing traffic loads and volumes, and an ageing population of bridges subject to various mechanisms of deterioration. The goal is to optimise the allocation of limited resources whilst maintaining their bridges in a safe and serviceable condition. Reliability analysis is one tool being...

  2. A data management infrastructure for bridge monitoring

    Science.gov (United States)

    Jeong, Seongwoon; Byun, Jaewook; Kim, Daeyoung; Sohn, Hoon; Bae, In Hwan; Law, Kincho H.

    2015-04-01

    This paper discusses a data management infrastructure framework for bridge monitoring applications. As sensor technologies mature and become economically affordable, their deployment for bridge monitoring will continue to grow. Data management becomes a critical issue not only for storing the sensor data but also for integrating with the bridge model to support other functions, such as management, maintenance and inspection. The focus of this study is on the effective data management of bridge information and sensor data, which is crucial to structural health monitoring and life cycle management of bridge structures. We review the state-of-the-art of bridge information modeling and sensor data management, and propose a data management framework for bridge monitoring based on NoSQL database technologies that have been shown useful in handling high volume, time-series data and to flexibly deal with unstructured data schema. Specifically, Apache Cassandra and Mongo DB are deployed for the prototype implementation of the framework. This paper describes the database design for an XML-based Bridge Information Modeling (BrIM) schema, and the representation of sensor data using Sensor Model Language (SensorML). The proposed prototype data management framework is validated using data collected from the Yeongjong Bridge in Incheon, Korea.

  3. 23 CFR 650.409 - Evaluation of bridge inventory.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409... Evaluation of bridge inventory. (a) Sufficiency rating of bridges. Upon receipt and evaluation of the bridge inventory, a sufficiency rating will be assigned to each bridge by the Secretary in accordance with...

  4. 33 CFR 118.85 - Lights on vertical lift bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  5. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Bridges requiring a USCG permit. 650.807 Section 650.807... BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges requiring a USCG... improvement or construction of a bridge over navigable waters except for the exemption exercised by FHWA...

  6. 33 CFR 118.65 - Lights on fixed bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  7. 33 CFR 118.70 - Lights on swing bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on swing bridges. 118.70 Section 118.70 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges....

  8. Finite element of multilayer surfacing systems on orthotropic steel bridges

    NARCIS (Netherlands)

    Li, J.; Liu, X.; Scarpas, A.; Tzimiris, G.

    2013-01-01

    Light weight orthotropic steel bridge decks have been widely utilized for bridges in seismic zones, movable bridges and long span bridges. In the last three decades, severe problems were reported in relation to asphaltic surfacing materials on orthotropic steel deck bridges. Earlier investigations h

  9. Light-weight aluminium bridges and bridge decks. An overview of recent applications

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Kluyver, D. de

    2008-01-01

    The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these pro

  10. Light-weight aluminium bridges and bridge decks. An overview of recent applications

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Kluyver, D. de

    2008-01-01

    The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these

  11. Bridge Workshop : Enhancing Bridge Performance, February 21-22, 2008, Reston, Virginia : workshop report

    Science.gov (United States)

    Sreenivas Alampalli; Sheila Rimal Duwadi; Reagan Sentelle Herman; Danielle D. Kleinhans; Khaled Mahmoud; James C. Ray; James P. Wacker; Nur Yazdani

    2008-01-01

    The participants to the workshop were given the charge to discuss (1) bridge design issues including best practices in design and detailing that could be used to improve durability, extend service life and prevent premature deterioration, (2) performance measures needed to better determine bridge condition, (3) technologies that could be used to monitor bridge life and...

  12. Bridging history and social psychology

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Yamamoto, Koji

    2012-01-01

    This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social psycholog......This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social...... psychologists can benefit from engaging with historical sources by being able to contextualise their findings and enrich their theoretical models. It is not only that all social and psychological phenomena have a history but this history is very much part of present-day and future developments. On the other...... hand historians can enhance their analysis of historical sources by drawing upon the conceptual tools developed in social psychology. They can “test” these tools and contribute to their validation and enrichment from completely different perspectives. Most important, as contributions to this special...

  13. Global monitoring concept for bridges

    Science.gov (United States)

    Bergmeister, Konrad; Santa, Ulrich

    2000-06-01

    Knowledge of the integrity of in-service structures on a continuous time basis is an ultimate objective for owners and maintenance authorities. The development of a life extension and/or replacement strategy for highway structures is a crucial point in an effective bridge management system. A key component of such a bridge management system is a means of surveillance techniques and determining the condition of an existing structure within the normative and budgetary constraints. Recent advances in sensing technologies and material/structure damage characterization combined with current developments in computations and communications have resulted in a significant interest in developing diagnostic technologies for monitoring the integrity of and for the detection of damages of structures. To identify anomalies and deterioration processes, it is essential to understand the relationships between the signal measurements and the real occurred phenomena. Therefore, the comparison of measured and calculated data in order to tune and validate the mechanical and numerical model assumptions is an integral part of any system analysis. Finally, the interpreted results of all measurements should be the basis for the condition assessment and the safety evaluation of a structure to facilitate replacement and repair decisions.

  14. The Bridge of Mandolin County

    Science.gov (United States)

    Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

    1999-12-01

    The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

  15. Salt-bridge energetics in halophilic proteins.

    Directory of Open Access Journals (Sweden)

    Arnab Nayek

    Full Text Available Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78% of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46% with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1 exceeds than that of bridge term (-7 kcal mol-1. Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic

  16. A Statistical Observation of Crowns and Bridges in 1988 Part 2 : Bridge

    OpenAIRE

    小林, 賢一; 小坂, 茂; 柳田, 史城; 稲生, 衡樹; 大島, 俊明; 高橋, 喜博; 岩井, 啓三; 甘利, 光治; 中根, 卓

    1991-01-01

    A study was made of 207 bridges which had been fabricated for patients at the Prosthodontic Clinic of Matsumoto Dental College during 1988. Some of results were as follows; 1) 47.3% of the patients were males and 52.7% were females. 2) 92.8% of the patients were between 20 and 69 years old. 3) 65.2%of the bridges were fabricated as 3-unit bridges. 4) 77.8% were fabricated as 1-pontic bridges. 5) There were fewer bridge retainers for the lower anterior segment than for other segments. 6) 52.3%...

  17. Lifetime Reliability Assessment of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed. Fi...

  18. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  19. The I-35W bridge Project Website

    DEFF Research Database (Denmark)

    Kampf, Constance

    How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...

  20. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  1. Methods and tools for diagnosing bridge structures

    Directory of Open Access Journals (Sweden)

    С.Ф. Філоненко

    2008-03-01

    Full Text Available  In the paper is reviewed the methods and means, which used at technical diagnostic of bridge designs. The general approaches to technical diagnostic, the main methods, primary converters and hardwares, which used on static and dynamic tests of bridge designs are reviewed.

  2. General framework for bridge life cycle design

    Institute of Scientific and Technical Information of China (English)

    Junhai MA; Airong CHEN; Jun HE

    2009-01-01

    Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics design, performance design, environ-mental and ecological design, inspection, maintenance and repair design as well as cost analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

  3. COUPLING VIBRATION OF VEHICLE-BRIDGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    陈炎; 黄小清; 马友发

    2004-01-01

    By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can't be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle.

  4. Bridges and the City: An Interdisciplinary Project.

    Science.gov (United States)

    Singer, Judith Y.; Goodman, Cecelia; Ridley, Theodora; Singer, Alan

    2000-01-01

    Describes an interdisciplinary project to help elementary school children discover the relationship among technology, history, and geography that involved the building of a model Brooklyn Bridge and considering the history and role of the real bridge. Suggestions for similar projects for other cities are appended. (JPB)

  5. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    the results obtained using the numerical models given in details in "Heavy Vehicles on Minor Highway Bridges : dynamic modelling of vehicles and bridges". The models are established using a ordinary vehicle which consists of a 48 t Scania with a 3 axle tractor and a 3 axle trailer, joined in a flexible hinge...

  6. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

  7. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  8. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

  9. Disturbance indicator benchmark for urban bridge construction

    NARCIS (Netherlands)

    Brouwer, J.; Vogel, R.; Thodesen, C.

    2013-01-01

    European bridges are today in a state of particular concern with over 50% of European urban bridges being more than 40 years old and thus requiring considerable maintenance or possibly even replacement [1]. This means that interventions in the present infrastructure have to be made while ensuring

  10. Passing the Einstein-Rosen bridge

    CERN Document Server

    Katanaev, M O

    2013-01-01

    We relax the requirement of geodesic completeness of a space-time. Instead, we require test particles trajectories to be smooth only in the physical sector. Test particles trajectories for Einstein--Rosen bridge are proved to be smooth in the physical sector, and particles can freely penetrate the bridge in both directions.

  11. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post-tensioning......, and gives a large positive bending moment below the load and a smaller negative bending moment in the unloaded side. When the Pearl-Chain Bridge concept is compared to other pre-fabricated arch bridge solutions we find a number of advantages when using Pearl-Chain Bridges: Straight elements, combination...

  12. (2,6-DIPHENYL) PHENYL METHACRYLATE .2. RADICAL COPOLYMERIZATION WITH METHYL-METHACRYLATE - THE T(G)S OF ITS COPOLYMERS WITH AN ADDENDUM ON THE POLYMERIZATION OF (2,6-DIPHENYL) PHENYL ACRYLATE

    NARCIS (Netherlands)

    TAN, YY; VANEKENSTEIN, GORA

    1994-01-01

    The radical copolymerization of (2,6-diphenyl) phenyl methacrylate (1) with methyl methacrylate in DMF with AIBN at 70-degrees-C has the reactivity rators r1 = 0.071 and r2 = 1.42, from which Q1 = 1.45 and e(l) = 1.20. The copolymers had M(n) s in the range of 10,000-40,000 and T(g) s ranging from 4

  13. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.;

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

  14. Seismic response of steel suspension bridge

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.B. [Lawrence Livermore National Lab., CA (United States); Astaneh-Asl, A. [California Univ., Berkeley, CA (United States). Dept. of Civil and Environmental Engineering

    1996-11-01

    Performing accurate, realistic numerical simulations of the seismic response of long-span bridges presents a significant challenge to the fields of earthquake engineering and seismology. Suspension bridges in particular represent some of the largest and most important man-made structures and ensuring the seismic integrity of these mega-structures is contingent on accurate estimations of earthquake ground motions and accurate computational simulations of the structure/foundation system response. A cooperative, multi-year research project between the Univ. of California and LLNL was recently initiated to study engineering and seismological issues essential for simulating the response of major structures. Part of this research project is focused on the response of the long-span bridges with the San Francisco-Oakland Bay Bridge serving as a case study. This paper reports on the status of this multi-disciplinary research project with emphasis on the numerical simulation of the transient seismic response of the Bay Bridge.

  15. The I-35W bridge Project Website

    DEFF Research Database (Denmark)

    Kampf, Constance

    How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...... collapsing during rush hour damaged the Minnesota Department of Transportation's reputation and resulted in the loss of public trust for the organization.  The ensuing bridge reconstruction project included a project website intended to rebuild this trust through transparency, community involvement......, and the use of multimodal features.  This paper looks at the I35-W bridge reconstruction project in Minneapolis through web-based communication by the Minnesota Department of Transportation (MnDOT) about the project. The MnDOT bridge reconstruction website will be examined using a combination of 1). Weick...

  16. [μ-Bis(diphenyl-arsino)methane-1:2κAs:As'][bis-(4-methoxy-phen-yl)phenyl-phosphine-3κP]-nona-carbonyl-1κC,2κC,3κC-triangulo-tri-ruthenium(0) dichloro-methane 0.15-solvate.

    Science.gov (United States)

    Shawkataly, Omar Bin; Khan, Imthyaz Ahmed; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-30

    The asymmetric unit of the title triangulo-triruthenium compound, [Ru(3)(C(25)H(22)As(2))(C(20)H(19)O(2)P)(CO)(9)]·0.15CH(2)Cl(2), contains one mol-ecule of the triangulo-triruthenium complex and one partially occupied dichloro-methane solvent mol-ecule. The dichloro-methane solvent lies across a crystallographic inversion center leading to the mol-ecule being disordered over two positions of equal occupancy. The bis-(diphenyl-arsino)methane ligand bridges an Ru-Ru bond and the monodentate arsine ligand bonds to the third Ru atom. Both the arsine ligands are equatorial with respect to the Ru(3) triangle. In addition, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three phospho-rus-bound benzene rings make dihedral angles of 72.7 (3), 80.9 (3) and 70.8 (2)° with each other. The dihedral angles between the two benzene rings are 79.9 (3) and 81.5 (2)° for the two diphenyl-arsino groups.

  17. Jumping from the Brooklyn Bridge.

    Science.gov (United States)

    Kurtz, R J; Pizzi, W F; Richman, H; Tiefenbrun, J

    1987-07-01

    In an attempt to identify factors contributing to survival of free fall and impact, we evaluated the records of four patients who survived a jump from the Brooklyn Bridge into the East River in New York Harbor between 1977 and 1985. All four patients were male and ranged in age from 22 to 67 years. They had free falls of between 41.0 and 48.8 meters. All of the patients were brought to the hospital within 24 minutes of entering the water. Three of the four had emergency surgical treatment and the fourth patient had only minor injuries. All four patients survived the suicide attempts. The length of the hospital stay ranged from two to 26 days.

  18. Building bridges … and accelerators

    CERN Multimedia

    2009-01-01

    Lyn Evans, the LHC project leader, was awarded an honorary doctorate from the University of Geneva (UNIGE) to celebrate his role not just in building accelerators, but also in building bridges between nations. He was one of four notables honoured at the event on Friday 5 June, coinciding with the University’s 450th Anniversary. Lyn Evans arriving at the ceremony with Archbishop Desmond Tutu. "It was a big surprise when I found out I’d been nominated," recounts Evans, "but it was an even bigger surprise to find out with whom I’d been nominated". At the ceremony Evans was awarded the honorary doctorate along with three others: Archbishop Desmond Tutu, who was acclaimed for his fight against apartheid in South Africa, Mary Robinson, first woman president of Ireland and former United Nations’ high commissioner of human rights, and Pascal Lamy, Director-General of the World Trade Organization. The award ceremony, known as the �...

  19. Xanthene-bridged cofacial bisporphyrins.

    Science.gov (United States)

    Chang, C J; Deng, Y; Heyduk, A F; Chang, C K; Nocera, D G

    2000-03-06

    The synthesis and characterization of cofacial bisporphyrins juxtaposed by xanthene-bridged pillars are presented. The one-pot preparation of the xanthene dialdehyde avoids the lengthy bridge synthesis accompanying other cofacial porphyrin systems, thus allowing for the facile preparation of homobimetallic zinc (10), copper (11), and nickel (12) complexes. The cofacial orientation of the two porphyrin macrocycles was confirmed by X-ray crystallography. Structural data are provided for bisporphyrins 10-12: 10 (C79H82N8OZn2), triclinic, space group P1, a = 11.2671(2) A, b = 14.9809(2) A, c = 20.4852(2) A, alpha = 101.6680(10) degrees, beta = 100.8890(10) degrees, gamma = 101.8060(10) degrees, Z = 2; 11 (C79H82N8OCu2), triclinic, space group P1, a = 11.21410(10) A, b = 14.9539(5) A, c = 20.6915(7) A, alpha = 101.810(2) degrees, beta = 101.044(2) degrees, gamma = 101.722(2) degrees, Z = 2; 12 (C79H82N8ONi2), monoclinic, space group C2/c, a = 24.1671(4) A, b = 10.669 A, c = 50.5080(9) A, beta = 99.553(2) degrees, Z = 8. Exciton interactions between the porphyrin rings are apparent in electronic spectra, consistent with the cofacial superstructure. The combination of structural and spectroscopic data provides a basis for the design of additional metal derivatives for the activation of dioxygen and other small molecules.

  20. Solubilities of benzene, toluene and diphenyl in the t-butyl alcohol + water mixtures and hydrophobic interaction

    Institute of Scientific and Technical Information of China (English)

    邹立壮; 杨冠英; 韩布兴; 刘瑞麟; 阎海科

    1999-01-01

    The solubilitices of benzene, toluene and diphenyl in mixed solvents of t-butyl alcohol (TBA) and water at 283.15, 288.15, 293.15 and 298.15 K have been determined by spectrophotometry. The mole fraction of TBA [x (TBA)] in the mixed solvent are 0.000, 0.010, 0.020, 0.030, 0.040, 0.045, 0.050, 0.060, 0.080 and 0.100, respectively. The standard Gibbs energies of solution of benzene, toluene and diphenyl in the mixed solvent have also been calculated based on the solubility data. The hydrophobic interactions (HI) for the pairs of benzene-benzene, methane-benzene and methane-methane in the mixed solvent were calculated and discussed.

  1. Polybrominated diphenyl ether (PBDE) concentrations and resulting exposure in homes in California: relationships among passive air, surface wipe and dust concentrations, and temporal variability

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam, electronics, and other home furnishings. A field study was conducted that enrolled 139 households from California, which has had more stringent flame retardant requirements than other countries...

  2. Polybrominated Diphenyl Ether (DE-71)Interferes with Thyroid Hormone Action Independent Of Effects On Circulating Levels of Thyroid Hormone in Male Rats

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are routinely found in human tissues including cord blood and breast milk. PBDEs may interfere with thyroid hormone (TH) during development, which could produce neurobehavioral deficits. An assumption in experimental and epidemiological stud...

  3. Application of aluminum-supported Pd, Rh, and Rh-Pd nanoparticles in supercritical carbon dioxide system for hydrodebromination of polybrominated diphenyl ethers.

    Science.gov (United States)

    Wu, Ben-Zen; Sun, Yu-Jie; Chen, Yan-Hua; Yak, Hwa Kwang; Yu, Jya-Jyun; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

    2016-08-01

    Al-powder-supported Pd, Rh, and Rh-Pd catalysts were synthesized through a spontaneous redox reaction in aqueous solutions. These catalysts hydrodebrominated 4- and 4,4'-bromodiphenyl ethers in supercritical carbon dioxide at 200 atm CO2 containing 10 atm H2 and 80 °C in 1 h. Diphenyl ether was the major product of Pd/Al. Rh/Al and Rh-Pd/Al further hydrogenated two benzene rings of diphenyl ether to form dicyclohexyl ether. The hydrogenolysis of CO bonds on diphenyl ether over Rh/Al and Rh-Pd/Al was observed to generate cyclohexanol and cyclohexane (Rh-Pd/Al among three catalysts is suggested to be used for ex situ degradation of polybrominated diphenyl ethers in supercritical carbon dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. The effects of diphenyl diselenide on oxidative stress biomarkers in Cyprinus carpio exposed to herbicide quinclorac (Facet®).

    Science.gov (United States)

    Cavalheiro de Menezes, Charlene; Leitemperger, Jossiele; Santi, Adriana; Lópes, Thais; Veiverberg, Cátia Aline; Peixoto, Sandra; Bohrer Adaime, Martha; Zanella, Renato; Vargas Barbosa, Nilda Berenice; Loro, Vania Lucia

    2012-07-01

    The occurrence of pollutants in the aquatic environment can produce severe toxic effects on non-target organisms, including fish. These sources of contamination are numerous and include herbicides, which represent a large group of toxic chemicals. Quinclorac, an herbicide widely applied in agriculture, induces oxidative stress due to free radical generation and changes in the antioxidant defense system. The aim of this study was to assess if dietary diphenyl diselenide (PhSe)₂ has a protective effect in tissues of fish species Cyprinus carpio exposed to the quinclorac herbicide. The fish were fed with either a standard or a diet containing 3.0 mg/Kg of diphenyl diselenide for 60 d. After were exposed to 1 mg/L of Facet® (quinclorac commercial formulation) for 192 h. At the end of the experimental period, parameters as thiobarbituric acid-reactive substance levels (TBARS), protein carbonyl, catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), nonprotein thiols (NPSH) and ascorbic acid in the liver, gills, brain and muscle were evaluated in Cyprinus carpio. In fish exposed to quinclorac and feeding with standard diet TBARS levels increased in liver and gills. However, SOD activity decreases in liver whereas no alterations were observed in catalase activity in this tissue. Quinclorac also decrease GST activity in liver and brain, NPSH in brain and muscle and ascorbic acid in muscle. Concerning protein carbonyl exposed to herbicide the fish did not show any alterations. The diphenyl diselenide supplemented diet reversed these effects, preventing increases in TBARS levels in liver and gills. GST activity was recovered to control values in liver. NPSH levels in brain and muscle increased remain near to control values. These results indicated that dietary diphenyl diselenide protects tissues against quinclorac induced oxidative stress ameliorating the antioxidant properties. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Diphenyl diselenide modulates gene expression of antioxidant enzymes in the cerebral cortex, hippocampus and striatum of female hypothyroid rats.

    Science.gov (United States)

    Roseni Mundstock Dias, Glaecir; Medeiros Golombieski, Ronaldo; de Lima Portella, Rafael; Pires do Amaral, Guilherme; Antunes Soares, Félix; Teixeira da Rocha, João Batista; Wayne Nogueira, Cristina; Vargas Barbosa, Nilda

    2014-01-01

    Cellular antioxidant signaling can be altered either by thyroid disturbances or by selenium status. To investigate whether or not dietary diphenyl diselenide can modify the expression of genes of antioxidant enzymes and endpoint markers of oxidative stress under hypothyroid conditions. Female rats were rendered hypothyroid by continuous exposure to methimazole (MTZ; 20 mg/100 ml in the drinking water) for 3 months. Concomitantly, MTZ-treated rats were either fed or not with a diet containing diphenyl diselenide (5 ppm). mRNA levels of antioxidant enzymes and antioxidant/oxidant status were determined in the cerebral cortex, hippocampus and striatum. Hypothyroidism caused a marked upregulation in mRNA expression of catalase, superoxide dismutase (SOD-1, SOD-3), glutathione peroxidase (GPx-1, GPx-4) and thioredoxin reductase (TrxR-1) in brain structures. SOD-2 was increased in the cortex and striatum, while TrxR-2 increased in the cerebral cortex. The increase in mRNA expression of antioxidant enzymes was positively correlated with the Nrf-2 transcription in the cortex and hippocampus. Hypothyroidism caused oxidative stress, namely an increase in lipid peroxidation and reactive oxygen species levels in the hippocampus and striatum, and a decrease in nonprotein thiols in the cerebral cortex. Diphenyl diselenide was effective in reducing brain oxidative stress and normalizing most of the changes observed in gene expression of antioxidant enzymes. The present work corroborates and extends that hypothyroidism disrupts antioxidant enzyme gene expression and causes oxidative stress in the brain. Furthermore, diphenyl diselenide may be considered a promising molecule to counteract these effects in a hypothyroidism state. © 2014 S. Karger AG, Basel.

  6. Diphenyl diselenide, a simple organoselenium compound, decreases methylmercury-induced cerebral, hepatic and renal oxidative stress and mercury deposition in adult mice.

    Science.gov (United States)

    de Freitas, Andressa Sausen; Funck, Vinícius Rafael; Rotta, Mariana dos Santos; Bohrer, Denise; Mörschbächer, Vanessa; Puntel, Robson Luís; Nogueira, Cristina Wayne; Farina, Marcelo; Aschner, Michael; Rocha, João Batista Teixeira

    2009-04-06

    Oxidative stress has been pointed out as an important molecular mechanism in methylmercury (MeHg) intoxication. At low doses, diphenyl diselenide ((PhSe)2), a structurally simple organoselenium compound, has been shown to possess antioxidant and neuroprotective properties. Here we have examined the possible in vivo protective effect of diphenyl diselenide against the potential pro-oxidative effects of MeHg in mouse liver, kidney, cerebrum and cerebellum. The effects of MeHg exposure (2 mg/(kg day) of methylmercury chloride 10 ml/kg, p.o.), as well as the possible antagonist effect of diphenyl diselenide (1 and 0.4 mg/(kg day); s.c.) on body weight gain and on hepatic, cerebellar, cerebral and renal levels of thiobarbituric acid reactive substances (TBARS), non-protein thiols (NPSH), ascorbic acid content, mercury concentrations and activities of antioxidant enzymes (glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD)) were evaluated after 35 days of treatment. MeHg caused an increase in TBARS and decreased NPSH levels in all tissues. MeHg also induced a decrease in hepatic ascorbic acid content and in renal GPx and CAT activities. Diphenyl diselenide (1 mg/kg) conferred protection against MeHg-induced hepatic and renal lipid peroxidation and at both doses prevented the reduction in hepatic NPSH levels. Diphenyl diselenide also conferred a partial protection against MeHg-induced oxidative stress (TBARS and NPSH) in liver and cerebellum. Of particular importance, diphenyl diselenide decreased the deposition of Hg in cerebrum, cerebellum, kidney and liver. The present results indicate that diphenyl diselenide can protect against some toxic effects of MeHg in mice. This protection may be related to its antioxidant properties and its ability to reduce Hg body burden. We posit that formation of a selenol intermediate, which possesses high nucleophilicity and high affinity for MeHg, accounts for the ability of diphenyl diselenide to ameliorate Me

  7. Effects of polybrominated diphenyl ethers on thyroid hormone, neurodevelopment and fertility in rodents and humans

    Directory of Open Access Journals (Sweden)

    Marta Czerska

    2013-08-01

    Full Text Available Polybrominated diphenyl ethers (PBDEs are used as flame retardants. Due to their widespread use in many consumer products, PBDEs can be found in food as well as in the environment. Their presence has also been found in the human serum, human adipose tissue and human breast milk. Results of experimental studies suggest that the presence of PBDE in the environment is not neutral to our health. In rats and mice exposed to PBDE disturbances in thyroid hormone homeostasis and reproductive system such as changes in reproductive organs weight and disorders in sperm motility and motion were found. In rodents, pre- and postnatal exposure to PBDE can cause neurobehavioral effects. Also in humans disturbances in thyroid hormone system, weight of reproductive organs and concentrations of sex hormones associated with PBDEs serum concentrations were found. Exposure to PBDEs during pregnancy may lead to slower mental and psychomotor development in infants. In this paper the results of previous animal a nd human studies are reviewed.

  8. Assessing bioaccumulation of polybrominated diphenyl ethers for aquatic species by QSAR modeling.

    Science.gov (United States)

    Mansouri, Kamel; Consonni, Viviana; Durjava, Mojca Kos; Kolar, Boris; Öberg, Tomas; Todeschini, Roberto

    2012-10-01

    Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in textiles, foams and plastics. Highly bioaccumulative with toxic effects including developmental neurotoxicity estrogen and thyroid hormones disruption, they are considered as persistent organic pollutants (POPs) and have been found in human tissues, wildlife and biota worldwide. But only some of them are banned from EU market. For the environmental fate studies of these compounds the bioconcentration factor (BCF) is one of the most important endpoints to start with. We applied quantitative structure-activity relationships techniques to overcome the limited experimental data and avoid more animal testing. The aim of this work was to assess the bioaccumulation of PBDEs by means of QSAR. First, a BCF dataset of specifically conducted experiments was modeled. Then the study was extended by predicting the bioaccumulation and biomagnification factors using some experimental values from the literature. Molecular descriptors were calculated using DRAGON 6. The most relevant ones were selected and resulting models were compared paying attention to the applicability domain. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Induction of adipocyte differentiation by polybrominated diphenyl ethers (PBDEs in 3T3-L1 cells.

    Directory of Open Access Journals (Sweden)

    Emily W Y Tung

    Full Text Available Polybrominated diphenyl ethers (PBDEs are a class of brominated flame retardants that were extensively used in commercial products. PBDEs are ubiquitous environmental contaminants that are both lipophilic and bioaccumulative. Effects of PBDEs on adipogenesis were studied in the 3T3-L1 preadipocyte cell model in the presence and absence of a known adipogenic agent, dexamethasone (DEX. A PBDE mixture designed to mimic body burden of North Americans was tested, in addition to the technical mixture DE-71 and the individual congener BDE-47. The mixture, DE-71, and BDE-47 all induced adipocyte differentiation as assessed by markers for terminal differentiation [fatty acid binding protein 4 (aP2 and perilipin] and lipid accumulation. Characterization of the differentiation process in response to PBDEs indicated that adipogenesis induced by a minimally effective dose of DEX was enhanced by these PBDEs. Moreover, C/EBPα, PPARγ, and LXRα were induced late in the differentiation process. Taken together, these data indicate that adipocyte differentiation is induced by PBDEs; they act in the absence of glucocorticoid and enhance glucocorticoid-mediated adipogenesis.

  10. Levels and distribution of polybrominated diphenyl ethers in Three Gorges Reservoir, China

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    Jingxian Wang

    2017-03-01

    Full Text Available Polybrominated diphenyl ethers (PBDEs were investigated in water, sediments, suspended sediments and biofilms in Three Gorges Reservoir (TGR, China. Results showed that dissolved bioavailable PBDEs in water of TGR collected with semipermeable membrane device (SPMD-based virtual organisms (VOs were very low in the range of n.d. to 811 pg/g lipid and the detected compounds were mainly low molecular BDEs such as BDE-15, 17, 28, 47, 49, 66, 99 and 100. The PBDE levels in the sediment core collected near the dam were also very low in the range of 84–300 pg/g dw and the detected compounds were mainly large molecular BDEs such as BDE-196, 197, 206, 207 and 208. In suspended sediments and biofilms, the levels of PBDEs ranged from 298 to 52,843 pg/g dw and the detected compounds were also mainly large molecular BDEs such as BDE- 196, 197, 201, 203, 206, 207, 208 and 209. The dominant compound was BDE-209 which accounted for more than 90% of the total BDEs. Therefore, large molecular BDEs tended to be attached on fine particles. The vertical profile of BDEs on suspended sediments (SS showed that SSs in the middle depth of water contained high level of BDE-209. The phenomenon indicated that most of BDE-209 did not settle into the sediment in front of the dam, instead transported further to downstream.

  11. Diphenyl Ditelluride Intoxication Triggers Histological Changes in Liver, Kidney, and Lung of Mice

    Directory of Open Access Journals (Sweden)

    Sônia Cristina Almeida da Luz

    2015-01-01

    Full Text Available Tellurium compounds may be cytotoxic to different cells types. Thus, this work evaluated the effect of diphenyl ditelluride ((PhTe2, an organotellurium commonly used in organic synthesis, on the morphology of liver, kidney, and lung. Adult mice were acutely (a subcutaneous single dose: 250 μmol/kg or subchronically (one daily subcutaneous dose: 10 or 50 μmol/kg for 7 and 14 days exposed to (PhTe2. Afterwards, the histological analyses of liver, kidney, and lungs were performed. Liver histology revealed that the hepatocytes of mice subchronically exposed to (PhTe2 presented cytoplasmic vacuolization, hydropic degeneration, and hyperchromatic nuclei. Subchronic exposure to 50 μmol/kg (PhTe2 also caused hepatic necrosis. Microvesicular and macrovesicular steatosis were identified in liver of mice acutely exposed to (PhTe2. Acute and subchronic intoxication with (PhTe2 induced changes on epithelial cells of renal tubules, namely, loss of brush border and cytoplasmatic vacuolization. Atrophy and hypertrophy, cast proteinaceous formation, and acute tubular necrosis were also identified in renal tissue. Mice subchronically exposed to 50 μmol/kg (PhTe2 developed intra-alveolar edema and alveolar wall congestion in some areas of lungs. Acute exposure to (PhTe2 did not cause histological changes in lungs. Our data show that (PhTe2 may be considered a histotoxic agent for liver, kidney, and lung.

  12. Bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers in wild frogs.

    Science.gov (United States)

    Liu, Peng-Yan; Du, Guo-Dong; Zhao, Ya-Xian; Mu, Yun-Song; Zhang, Ai-Qian; Qin, Zhan-Fen; Zhang, Xiao-You; Yan, Shi-Shuai; Li, Yan; Wei, Rong-Guo; Qin, Xiao-Fei; Yang, Yong-Jian

    2011-08-01

    To investigate bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers (PBDEs) in amphibians, we collected adult frogs (Rana limnocharis) from a rice field in an e-waste recycling site in China. We found that ∑PBDEs in the whole frogs and various tissues (brain, liver, testis and egg) ranged from 17.10 to 141.11 ng g(-1) wet weight. Various tissues exhibited a similar PBDE congener profile, which was characterized by intermediate brominated congeners (BDE-99 and BDE-153) as the largest contributors, with less lower brominated congeners (BDE-28 and BDE-47) and higher brominated congeners (BDE-209). The maternal transfer capacity of PBDEs declined with the increase in bromine numbers of PBDE congeners. We suggest that the bromine atom number (the molecular size, to some degree) might be a determining factor for the maternal transport of a PBDE congener rather than K(ow) (Octanol-Water partition coefficient), which expresses a compound's lipophilicity. ∑PBDEs concentrations in frogs decreased over time during a depuration period of 54 days when these wild frogs were brought to the lab from the e-waste recycling site. The half-life of ∑PBDEs was 35 days, with about 14 days for BDE-47, and 36 and 81 days for BDE-99 and BDE-153, respectively. The data shows that the elimination of PBDEs has no essential difference from aquatic and terrestrial species.

  13. GC-MS analysis of polybrominated diphenyl ethers in Lake Erie

    Science.gov (United States)

    Vagula, Mary C.; Vartak, Marissa; Tallmadge, Weslene

    2012-06-01

    Lake Erie is one of the five great lakes of North America. It is the shallowest, the warmest, and the most biologically productive of the Great Lakes producing more fish than all of the other four lakes combined. It is also a source of drinking water for 11 million people and a recreational asset. On the flipside, it is also very vulnerable and troubled with environmental challenges because it has the smallest water volume, but the greatest pressures from the human settlement. One of the many issues faced by the Lake is pollution. It receives larger loads of many pollutants than any other Great Lake. Even with the best pollution controls many pesticides and organohalogens continue to enter the lake. Polybrominated diphenyl ethers (PBDEs) are a class of flame-retardants that have been used in a variety of consumer products since the 1970s. They are added to many commercial and household products such as computers, foam mattresses, carpets, etc. Being largely non-polar and chemically stable, these chemicals are extremely lipophilic and resist degradation in the environment, thus giving them a high affinity for their bioaccumulation. Due to these properties PBDEs have become ubiquitous environmental contaminants. These compounds are reported to be endocrine disruptors and could cause oxidative damage. This report presents the sample preparation protocol, the GC-MS analysis of PBDEs in Lake Erie sediment samples.

  14. [Distribution of polybrominated diphenyl ethers in aquatic species from the Pearl River Estuary].

    Science.gov (United States)

    Xiang, Cai-hong; Luo, Xiao-jun; Yu, Mei; Meng, Xiang-zhou; Mai, Bi-xian; Zeng, Eddy

    2006-09-01

    Polybrominated diphenyl ethers (PBDEs) were detected in biota samples collected from the Pearl River Estuary. The concentrations of sigma10 PBDEs (BDE28, 47, 66, 100, 99, 85, 154, 153, 138, 183) in fish species (including Platycephalus indicus, Pseudosiaena crocea , Pampus argenteus, Cynoglossus robustus, and Harpodon nehereus), shrimps (including Metapenaeus ensis and Metapenaeus affinis) and Squilla oratoria were from 37.8 ng x g(-1) to 407.1 ng x g(-1) (normalized to lipid), from 49.0 ng x g(-1) to 239.1 ng x g(-1) and from 142 ng x g(-1) to 444.5 ng x g(-1), respectively. BDE47 was the dominant congener in all biota samples, with a contribution to sigma10 PBDEs ranging from 53.7% to 66.9%. Differences in concentrations of PBDEs and PBDE patterns in different species may be related to the different feeding habit, living environment and uptaking or elimination rate. High ratios of concentrations of PBDEs in liver /muscle in fish species indicated that PBDEs tended to accumulate more in liver than in muscle.

  15. Qualitative and quantitative simulation of androgen receptor antagonists: A case study of polybrominated diphenyl ethers.

    Science.gov (United States)

    Wu, Yang; Shi, Wei; Xia, Pu; Zhang, Xiaowei; Yu, Hongxia

    2017-12-15

    Recently, great attention has been paid to the identification and prediction of the androgen disrupting potencies of polybrominated diphenyl ethers (PBDEs). However, few existing models can discriminate active and inactive compounds, which make the quantitative prediction process including the quantitative structure-activity relationship (QSAR) technique unreliable. In this study, different grouping methods were investigated and compared for qualitative identification, including molecular docking and molecular dynamics simulations (MD). The results showed that qualitative identification based on MD, which is lab-independent, accurate and closer to the real transcriptional activation process, could separate 90.5% of active and inactive chemicals and was preferred. The 3D-QSAR models built as the quantitative simulation method showed r(2) and q(2) values of 0.513 and 0.980, respectively. Together, a novel workflow combining qualitative identification and quantitative simulations was generated with processes including activeness discrimination and activity prediction. This workflow, for analyzing the antagonism of androgen receptor (AR) of PBDEs is not only allowing researchers to reduce their intense laboratory experiments but also assisting them in inspecting and adjusting their laboratory systems and results. Copyright © 2017. Published by Elsevier B.V.

  16. Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Moral, Monica; Garcia, Gregorio [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Penas, Antonio [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Garzon, Andres; Granadino-Roldan, Jose M. [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Melguizo, Manuel [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Fernandez-Gomez, Manuel, E-mail: mfg@ujaen.es [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer We study properties of Ph{sub 2}Tz and (PhTz){sub n}Ph as candidates for organic electronics. Black-Right-Pointing-Pointer The synthesis of Ph{sub 2}Tz was performed through a modified Pinner-type reaction. Black-Right-Pointing-Pointer IR/Raman spectra allowed to conclude that Ph{sub 2}Tz is nearly planar in liquid phase. Black-Right-Pointing-Pointer Electronic structure was studied by UV-Vis/TD-DFT methods in different solvents. Black-Right-Pointing-Pointer Bandgap, E{sub LUMO}, electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph{sub 2}Tz) and some oligomeric derivatives. Ph{sub 2}Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

  17. Brominated diphenyl ether levels. A comparison of tributary sediments versus biosolid material

    Energy Technology Data Exchange (ETDEWEB)

    Kolic, T.M.; MacPherson, K.A.; Reiner, E.J. [Ontario Ministry of the Environment, Laboratory Services Branch, Toronto, ON (Canada); Ho, T.; Kleywegt, S. [Ontario Ministry of the Environment, Standards Development Branch, Toronto, ON (Canada); Dove, A.; Marvin, C. [Environment Canada, Burlington, ON (Canada)

    2004-09-15

    PBDEs are persistent in the environment, have low water solubility and are known to have a tendency to bioaccumulate in wildlife and humans. There are 209 possible PBDE congeners. There has been concern over the bioaccumulation of these compounds since they have been found in mother's milk. Some of the brominated diphenyl ethers are known to metabolize into hydroxylated compounds and these metabolites are known to compete with and reduce thyroxine (T4) from binding to the thyroxine binding protein, transthyretin. This disrupts the thyroid hormone system interaction that has recently been notable amongst women in the form of hypothyroidism that can affect the fetus development in the form of neurodevelopmental deficits. There have been reports of estrogenic activities regarding PBDEs and their hydroxylated counterparts. Information such as this is indicative that PBDEs are endocrine disruptors. Due to their lipophilic nature, PBDEs have a high binding affinity to particulates and accumulate in sediments. Various reports on sediments and sludge type matrices have been reported in Austria, Switzerland, Netherlands and Canada. The following paper is a presentation of levels of PBDEs found in Tributary sediments and their comparison of levels to nearby biosolid sampling locations along Lake Ontario.

  18. Polybrominated diphenyl ethers (PBDEs in sediment and fish tissues from Lake Chaohu, central eastern China

    Directory of Open Access Journals (Sweden)

    Yang Suwen

    2015-06-01

    Full Text Available Polybrominated diphenyl ethers (PBDEs levels in environmental media have increased over the last 20-25 years in the world. In aquatic environments PBDEs were found to be accumulated along food chain and Endocrine disruptors toxicity. In this study PBDEs were investigated in sediment and fish tissues from Lake Chaohu in central eastern China. There were 10 PBDEs congeners detected out of all 41 PBDEs. BDE-47 was of the highest with 5.17 ng/g in sediment and 58.47 ng/g in fish. PBDEs were evenly distributed across the surface sediment in the whole lake. It implied that the main source of PBDEs may not be an inflow river like Nanfei. Tissue distribution patterns of PBDEs in four fish species were in the order of BDE-47 > BDE-99 > BDE-100 > BDE-66 > BDE-138 > BDE-183 > BDE-154 > BDE-153. Octa- and deca-BDEs were below the detection limit. The concentrations of all PBDE congeners were higher in gills, livers, and kidneys than those in muscles and adipose tissue. Furthermore, PBDEs in different tissues had some different distribution patterns with fish size. Those discrepancies appeared to be correlated with the PBDEs pollution fluxes varying with the change of the year and their metabolism divergences in fish tissues.

  19. Diphenyl Ditelluride Intoxication Triggers Histological Changes in Liver, Kidney, and Lung of Mice

    Science.gov (United States)

    da Luz, Sônia Cristina Almeida; Daubermann, Melissa Falster; Thomé, Gustavo Roberto; dos Santos, Matheus Mülling; Ramos, Angelica; Torres Salazar, Gerson; da Rocha, João Batista Teixeira; Barbosa, Nilda Vargas

    2015-01-01

    Tellurium compounds may be cytotoxic to different cells types. Thus, this work evaluated the effect of diphenyl ditelluride ((PhTe)2), an organotellurium commonly used in organic synthesis, on the morphology of liver, kidney, and lung. Adult mice were acutely (a subcutaneous single dose: 250 μmol/kg) or subchronically (one daily subcutaneous dose: 10 or 50 μmol/kg for 7 and 14 days) exposed to (PhTe)2. Afterwards, the histological analyses of liver, kidney, and lungs were performed. Liver histology revealed that the hepatocytes of mice subchronically exposed to (PhTe)2 presented cytoplasmic vacuolization, hydropic degeneration, and hyperchromatic nuclei. Subchronic exposure to 50 μmol/kg (PhTe)2 also caused hepatic necrosis. Microvesicular and macrovesicular steatosis were identified in liver of mice acutely exposed to (PhTe)2. Acute and subchronic intoxication with (PhTe)2 induced changes on epithelial cells of renal tubules, namely, loss of brush border and cytoplasmatic vacuolization. Atrophy and hypertrophy, cast proteinaceous formation, and acute tubular necrosis were also identified in renal tissue. Mice subchronically exposed to 50 μmol/kg (PhTe)2 developed intra-alveolar edema and alveolar wall congestion in some areas of lungs. Acute exposure to (PhTe)2 did not cause histological changes in lungs. Our data show that (PhTe)2 may be considered a histotoxic agent for liver, kidney, and lung. PMID:26236579

  20. Rational design and synthesis of novel diphenyl ether derivatives as antitubercular agents

    Directory of Open Access Journals (Sweden)

    Kar SS

    2016-07-01

    Full Text Available Sidhartha S Kar,1 Varadaraj Bhat G,1 Praveen PN Rao,2 Vishnu P Shenoy,3 Indira Bairy,4 G Gautham Shenoy1 1Department of Pharmaceutical Chemistry, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal, India; 2School of Pharmacy, Health Sciences Campus, University of Waterloo, Waterloo, ON, Canada; 3Department of Microbiology, Kasturba Medical College, Manipal, 4Melaka-Manipal Medical College, Manipal University, Manipal, India Abstract: A series of triclosan mimic diphenyl ether derivatives have been synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. The binding mode of the compounds at the active site of enoyl-acyl carrier protein reductase of M. tuberculosis has been explored. Among them, compound 10b was found to possess antitubercular activity (minimum inhibitory concentration =12.5 µg/mL comparable to triclosan. All the synthesized compounds exhibited low levels of cytotoxicity against Vero and HepG2 cell lines, and three compounds 10a, 10b, and 10c had a selectivity index more than 10. Compound 10b was also evaluated for log P, pKa, human liver microsomal stability, and % protein binding, in order to probe its druglikeness. Based on the antitubercular activity and druglikeness profile, it may be concluded that compound 10b could be a lead for future development of antitubercular drugs. Keywords: dihenyl ether, tuberculosis, cytotoxicity, druglikeness