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Sample records for repellent efficacy studies

  1. Advancing the science of EPA guidelines for sponsor-financed topical insect repellent efficacy studies.

    Science.gov (United States)

    Young, Linda J; Fisher, Celia B

    2010-02-01

    In 1999, the US Environmental Protection Agency (EPA) published guidelines for product performance testing of skin-applied insect repellents, which provide guidance for topical insect repellent efficacy studies. EPA subsequently uses these sponsor-financed studies in their evaluation of proposed label claims. This paper reviews some of the statistical flaws in the proposed revisions to these guidelines and suggests possible improvements. This review is important because EPA's revisions to the 1999 guidelines do not address these issues.

  2. Relative efficacy of various oils in repelling mosquitoes.

    Science.gov (United States)

    Ansari, M A; Razdan, R K

    1995-09-01

    Field studies were carried out to determine the relative efficacy of repellant action of vegetable, essential and chemical base oils against vector mosquitoes. Results revealed that essential oils viz. Cymbopogan martinii martinii var. Sofia (palmarosa), Cymbopogan citratus (lemon grass) and Cymbopogan nardus (citronella) oils are as effective as chemical base oil namely mylol. These oils provide almost complete protection against Anopheles culicifacies and other anopheline species. Per cent protection against Culex quinquefasciatus ranged between 95-96%. Camphor (C. camphora) oil also showed repellent action and provided 97.6% protection against An. culicifacies and 80.7% against Cx. quinquefasciatus. Vegetable oils namely mustard (B. compestris) and coconut (C. nucisera) showed repellent action, however the efficacy of these oils was not much pronounced against Cx. quinquefasciatus. Results of statistical analysis revealed significant difference between vegetable and essential oils (p mosquitoes. Essential oils were found marginally superior in repellancy than camphor and mylol (p < 0.01) against An. culicifacies and Cx. quinquefasciatus.

  3. Plant-based insect repellents: a review of their efficacy, development and testing

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    Maia Marta

    2011-03-01

    Full Text Available Abstract Plant-based repellents have been used for generations in traditional practice as a personal protection measure against host-seeking mosquitoes. Knowledge on traditional repellent plants obtained through ethnobotanical studies is a valuable resource for the development of new natural products. Recently, commercial repellent products containing plant-based ingredients have gained increasing popularity among consumers, as these are commonly perceived as “safe” in comparison to long-established synthetic repellents although this is sometimes a misconception. To date insufficient studies have followed standard WHO Pesticide Evaluation Scheme guidelines for repellent testing. There is a need for further standardized studies in order to better evaluate repellent compounds and develop new products that offer high repellency as well as good consumer safety. This paper presents a summary of recent information on testing, efficacy and safety of plant-based repellents as well as promising new developments in the field.

  4. The efficacy of repellents against Aedes, Anopheles, Culex and Ixodes spp. - a literature review.

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    Lupi, Eleonora; Hatz, Christoph; Schlagenhauf, Patricia

    2013-01-01

    Travellers are confronted with a variety of vector-borne threats. Is one type of repellent effective against all biting vectors? The aim of this review is to examine the literature, up to December 31st, 2012, regarding repellent efficacy. We searched PubMed for relevant papers. Repellents of interest were DEET, Icaridin as well as other piperidine-derived products (SS220), Insect Repellent (IR) 3535 (ethyl-butylacetyl-amino-propionat, EBAAP) and plant-derived products, including Citriodora (para-menthane-3,8-diol). As vectors, we considered the mosquito species Anopheles, Aedes and Culex as well as the tick species Ixodes. We selected only studies evaluating the protective efficacy of repellents on human skin. We reviewed a total of 102 publications. Repellents were evaluated regarding complete protection time or as percentage efficacy [%] in a time interval. We found no standardized study for tick bite prevention. Regarding Aedes, DEET at concentration of 20% or more, showed the best efficacy providing up to 10 h protection. Citriodora repellency against this mosquito genus was lower compared to the other products. Also between subspecies a difference could be observed: Ae. aegypti proved more difficult to repel than Ae. Albopictus. Fewer studies have been conducted on mosquito species Anopheles and Culex. The repellency profile against Anopheles species was similar for the four principal repellents of interest, providing on average 4-10 h of protection. Culex mosquitoes are easier to repel and all four repellents provided good protection. Few studies have been conducted on the tick species Ixodes. According to our results, the longest protection against Ixodes scapularis was provided by repellents containing IR3535, while DEET and commercial products containing Icaridin or PMD showed a better response than IR3535 against Ixodes ricinus. Many plant-based repellents provide only short duration protection. Adding vanillin 5% to plant-based repellents and to DEET

  5. A community-wide study of malaria reduction: evaluating efficacy and user-acceptance of a low-cost repellent in northern Ghana.

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    Dadzie, Samuel; Boakye, Daniel; Asoala, Victor; Koram, Kwadwo; Kiszewski, Anthony; Appawu, Maxwell

    2013-02-01

    NO MAS (NM) mosquito repellent was evaluated in two farming villages (4 km apart) in the Kassena Nankana district of northern Ghana. We determined its efficacy against local malaria vectors, degree of user acceptance, and its effect on malaria prevalence in households using insecticide-treated bed nets. The average protective efficacy of NM against Anopheles mosquitoes over 9 hours was 89.6%. Controls averaged 86 bites/person/night versus 9 bites/person/night with the use of NM. Use of repellent was associated with a decrease of absolute malaria prevalence by 19.2% in the repellent village and by 6.5% in the control village (45.5 to 26.3, and 29.5 to 23.0, respectively). The user-acceptance rate of NM repellent was 96.1%. Ten percent (10%) of repellent users reported irritation as the main adverse effect during the period. Eighty-five percent (85%) of the users found the odor of NM appealing and 87% reported no inconvenience in applying the repellent daily.

  6. Sustained efficacy of the novel topical repellent TT-4302 against mosquitoes and ticks.

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    Bissinger, B W; Kennedy, M K; Carroll, S P

    2016-03-01

    Mosquitoes and ticks are blood-feeding pests of humans and animals that can vector many important aetiological agents of disease. Previous research demonstrated that TT-4302 (Guardian(®) Wilderness) containing 5% geraniol applied to human subjects gave 5-6 h of repellency against mosquitoes (depending on species) and was repellent to ticks in vitro. This study was conducted to obtain an independent third-party evaluation of TT-4302 against Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) mosquitoes and to test the efficacy of the product in the field against ticks. TT-4302 provided an average of 6.5 h of repellency of ≥ 95% [Weibull mean protection time: 7.4 h, 95% confidence interval (CI) 5.8-11.3 h] for St. aegypti, whereas a 15% DEET formulation provided 4.7 h of repellency (Weibull mean protection time: 5.2 h, 95% CI 3.7-6.9 h). In tick field trials, the efficacy of TT-4302 did not differ significantly from that of a 25% DEET formulation against Amblyomma americanum (Ixodida: Ixodidae). TT-4302 was 81.3% repellent at 2.5 h after application, whereas DEET was 77.2% repellent at the same time-point. Results at 3.5 h after application were 71.4% for TT-4302 and 72.9% for DEET.

  7. Repellent plants provide affordable natural screening to prevent mosquito house entry in tropical rural settings--results from a pilot efficacy study.

    Directory of Open Access Journals (Sweden)

    Frank C Mng'ong'o

    Full Text Available Sustained malaria control is underway using a combination of vector control, prompt diagnosis and treatment of malaria cases. Progress is excellent, but for long-term control, low-cost, sustainable tools that supplement existing control programs are needed. Conventional vector control tools such as indoor residual spraying and house screening are highly effective, but difficult to deliver in rural areas. Therefore, an additional means of reducing mosquito house entry was evaluated: the screening of mosquito house entry points by planting the tall and densely foliated repellent plant Lantana camara L. around houses. A pilot efficacy study was performed in Kagera Region, Tanzania in an area of high seasonal malaria transmission, where consenting families within the study village planted L. camara (Lantana around their homes and were responsible for maintaining the plants. Questionnaire data on house design, socioeconomic status, malaria prevention knowledge, attitude and practices was collected from 231 houses with Lantana planted around them 90 houses without repellent plants. Mosquitoes were collected using CDC Light Traps between September 2008 and July 2009. Data were analysed with generalised negative binomial regression, controlling for the effect of sampling period. Indoor catches of mosquitoes in houses with Lantana were compared using the Incidence Rate Ratio (IRR relative to houses without plants in an adjusted analysis. There were 56% fewer Anopheles gambiae s.s. (IRR 0.44, 95% CI 0.28-0.68, p<0.0001; 83% fewer Anopheles funestus s.s. (IRR 0.17, 95% CI 0.09-0.32, p<0.0001, and 50% fewer mosquitoes of any kind (IRR 0.50, 95% CI 0.38-0.67, p<0.0001 in houses with Lantana relative to controls. House screening using Lantana reduced indoor densities of malaria vectors and nuisance mosquitoes with broad community acceptance. Providing sufficient plants for one home costs US $1.50 including maintenance and labour costs, (30 cents per person. L

  8. Evaluation of repellents efficacy against Anopheles gambiae s.s.; an anthropophilic malaria vector

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    Gerald Katunzi

    2015-03-01

    Full Text Available Reduction of human-vector contact is of epidemiological importance in malaria control. Repellents can be used to complement the existing intervention tools against malaria vectors. Thus, evaluation of efficacy of additional mosquito repellents and /or attractants is of great significance for personal protection tools against malaria vectors. This study evaluated the repellence efficacy of menthol-propylene-glycol-carbonate (MR08 and Lemon grass (LG against Anopheles gambiae. Experiments were performed in a room which was 7.8 meters by 3.9 meters in dimension. Three experimental set ups were performed, i comparison of 10 hours worn sock and unworn sock;  ii comparison of  10 hours worn sock treated with MR08 against worn sock alone, and iii comparison of  10 hours worn sock treated with LG against worn sock alone. CDC miniature light traps were used to evaluate the recovery of released mosquitoes using both repellents and attractants. After initial trials, a concentration of 500 ppm was selected for all repellents. Among 1800 mosquitoes released into the experimental room, 1230 were recovered by CDC light traps while the remaining 570 were found within the experimental room. Among those collected by light traps, 1185 were collected by traps with worn sock alone. A worn sock treated with either MR08 or Lemon grass significantly repelled An.gambiae compared to worn sock alone. The findings of this study demonstrate that MR08 and lemon grass have inhibition efficiency against mosquito stings but further field evaluations are required for observed findings against wild populations of An.gambiae at lower Moshi using slow release method.

  9. Performance of the plant-based repellent TT-4302 against mosquitoes in the laboratory and field and comparative efficacy to 16 mosquito repellents against Aedes aegypti (Diptera: Culicidae).

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    Bissinger, B W; Schmidt, J P; Owens, J J; Mitchell, S M; Kennedy, M K

    2014-03-01

    Repellent efficacy of the plant-based repellent, TT-4302 (5% geraniol), was compared with 16 other products in laboratory arm-in-cage trials against Aedes aegypti (L). Eight repellents (Badger, BioUD, Burt's bees, California Baby, Cutter Natural, EcoSMART, Herbal Armor, and SkinSmart) exhibited a mean repellency below 90% to Ae. aegypti at 0.5 h after application. Three repellents (Buzz Away Extreme, Cutter Advanced, and OFF! Botanicals lotion) fell below 90% repellency 1.5 h after application. TT-4302 exhibited 94.7% repellency 5 h posttreatment, which was a longer duration than any of the other repellents tested. The positive control, 15% DEET (OFF! Active), was repellent for 3 h before activity dropped below 90%. Additional arm-in-cage trials comparing TT-4302 with 15% DEET were carried out against Anopheles quadrimaculatus Say. At 6 h after treatment, TT-4302 provided 95.2% repellency while DEET exhibited 72.2%. In North Carolina field trials, TT-4302 provided 100% repellency 5 h after application against Aedes albopictus Skuse while DEET provided 77.6% repellency. These results demonstrate that TT-4302 is an efficacious plant-based repellent that provides an extended duration of protection compared with many other commercially available products.

  10. Bird-repellent effects on bait efficacy for control of invasive mammal pests.

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    Cowan, Phil; Brown, Sam; Forrester, Guy; Booth, Lynn; Crowell, Michelle

    2015-08-01

    Repellents to reduce crop damage from birds and mammals have been investigated extensively, but their efficacy in reducing risk to non-target birds in aerial poisoning operations for control of mammal pests is less known. We assessed the impact on bait acceptability, palatability and kill efficacy for captive wild rats (Rattus rattus L.) and possums (Trichosurus vulpecula Kerr) of adding bird repellents (anthraquinone and d-pulegone) to baits used for their control in food choice trials. For possums, anthraquinone at 0.25% reduced acceptability and palatability but not the efficacy of poison baits, whereas d-pulegone at 0.17% had no significant effects. Rats showed little response to d-pulegone, but developed a marked aversion to prefeed baits containing anthraquinone at both 0.1 and 0.25%, such that almost no exposed rats ate poison baits and mortality was reduced significantly. The aversion induced by anthraquinone was generalised to the bait, as anthraquinone-exposed rats did not eat bait with only d-pulegone. Anthraquinone is not suitable for inclusion in bait for rat control at the concentrations tested, and also presents some risk to efficacy for possum control. D-pulegone would be suitable for inclusion in bait for possums and rats, but problems related to its volatility in bait manufacture and storage would need to be overcome. Further studies should focus on an alternative secondary repellent, or on establishing the maximum anthraquinone concentration that does not reduce efficacy for rats and testing whether or not that concentration is sufficient to repel native birds from baits reliably. © 2014 Society of Chemical Industry.

  11. The formulation of the essential oil of Piper aduncum Linnaeus (Piperales: Piperaceae) increases its efficacy as an insect repellent.

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    Mamood, S N H; Hidayatulfathi, O; Budin, S B; Ahmad Rohi, G; Zulfakar, M H

    2017-02-01

    The essential oil (EO) of Piper aduncum Linnaeus, known as 'sireh lada' to locals Malaysian, has the potential to be used as an alternative to synthetic insect repellents such as N,N-diethyl-meta-toluamide. However, the EO's efficacy as a repellent decreases after application due to the high volatility of its active ingredients. A number of studies have showed that optimizing the formulation of plant-based EOs can improve their efficacy as repellents. The present study sought to evaluate the effectiveness of 10% P. aduncum EO in ethanol and in three different semisolid formulations: ointment, cream and gel. These formulations were tested on Aedes aegypti under laboratory conditions. Each formulation was applied to the subject's hands, which were then inserted into a cage containing 25 nulliparous A. aegypti. The number of mosquitoes landing on or biting each subject's hand was recorded, and the repellency percentage, landing/biting percentage and protection time for each of the formulations were compared. There were no statistically significant differences between the semisolid EO formulations with regards to the repellency percentage and the landing/biting percentage at 4 h post-application. All three semisolid EO formulations were able to repel >65% of the A. aegypti at 4 h post-application. The EO ointment formulation provided a protection time (182.5 ± 16.01 min) that was statistically significantly longer than that associated with the EO gel formulation (97.5 ± 14.93 min). Meanwhile, the EO cream formulation provided a protection time of 162.5 ± 6.29 min. As the EO cream and ointment formulations displayed better repellent properties than the EO gel formulation, they appear to be the most promising P. aduncum EO formulations to be developed and commercialized as alternatives to synthetic repellents.

  12. Efficacy of Some Wearable Devices Compared with Spray-On Insect Repellents for the Yellow Fever Mosquito, Aedes aegypti (L.) (Diptera: Culicidae).

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    Rodriguez, Stacy D; Chung, Hae-Na; Gonzales, Kristina K; Vulcan, Julia; Li, Yiyi; Ahumada, Jorge A; Romero, Hector M; De La Torre, Mario; Shu, Fangjun; Hansen, Immo A

    2017-01-01

    The current Zika health crisis in the Americas has created an intense interest in mosquito control methods and products. Mosquito vectors of Zika are of the genus Aedes, mainly the yellow fever mosquito, Aedes aegypti. L. The use of repellents to alter mosquito host seeking behavior is an effective method for the prevention of mosquito-borne diseases. A large number of different spray-on repellents and wearable repellent devices are commercially available. The efficacies of many repellents are unknown. This study focuses on the efficacy of eleven different repellents in reducing the number of Ae. aegypti female mosquitoes attracted to human bait. We performed attraction-inhibition assays using a taxis cage in a wind tunnel setting. One person was placed upwind of the taxis cage and the mosquito movement towards or away from the person was recorded. The person was treated with various spray-on repellents or equipped with different mosquito repellent devices. We found that the spray-on repellents containing N,N-Diethyl-meta-toluamide and p-menthane-3,8-diol had the highest efficacy in repelling mosquitoes compared to repellents with other ingredients. From the five wearable devices that we tested, only the one that releases Metofluthrin significantly reduced the numbers of attracted mosquitoes. The citronella candle had no effect. We conclude that many of the products that we tested that were marketed as repellents do not reduce mosquito attraction to humans. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  13. Rodent-repellent studies. III. Advanced studies in the evaluation of chemical repellents

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    Bellack, E.; DeWitt, J.B.

    1949-01-01

    In order to bridge the gap between preliminary screening of chemicals for potential rodent repellency and the application ofthese compounds to paper cartons, more advanced studies in the evaluation ofpromising materials have been carried out. These studies have resulted in: (1) a modification of the food acceptance technique which eliminates doubtful compounds and also provides a closer analogy to the ultimate goal, and (2) a method for rapidly testing chemicals incorporated in paper. When the results of these latter tests are expressed as a function of time, it can be shown that a distinct correlation exists between the deterrency exhibited by treated paper and the repellency of treated food.

  14. Synergy between repellents and non-pyrethroid insecticides strongly extends the efficacy of treated nets against Anopheles gambiae

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    N'Guessan Raphaël

    2007-03-01

    Full Text Available Abstract Background To manage the kdr pyrethroid-resistance in Anopheline malaria vectors, new compounds or new strategies are urgently needed. Recently, mixing repellents (DEET and a non-pyrethroid insecticide (propoxur was shown to be as effective as deltamethrin, a standard pyrethroid, under laboratory conditions, because of a strong synergy between the two compounds. In the present study, the interactions between two repellents (DEET and KBR 3023 and a non-pyrethroid insecticide (pyrimiphos methyl or PM on netting were investigated. The residual efficacy and the inhibition of blood feeding conferred by these mixtures were assessed against Anopheles gambiae mosquitoes. Methods DEET and KBR 3023 were mixed with pyrimiphos methyl (PM, a organophosphate (OP insecticide. The performance of mono- and bi-impregnated nets against adult mosquitoes was assessed using a miniaturized, experimental hut system (laboratory tunnel tests that allows expression of behavioural responses to insecticide, particularly the mortality and blood feeding effects. Results Both mixtures (PM+DEET and PM+KBR3023 induced 95% mortality for more than two months compared with less than one week for each compound used alone, then reflecting a strong synergy between the repellents and PM. A similar trend was observed with the blood feeding rates, which were significantly lower for the mixtures than for each component alone. Conclusion Synergistic interactions between organophosphates and repellents may be of great interest for vector control as they may contribute to increase the residual life of impregnated materials and improve the control of pyrethroid-resistance mosquitoes. These results prompt the need to evaluate the efficacy of repellent/non-pyrethroid insecticide mixtures against field populations of An. gambiae showing high level of resistance to Ops and pyrethroids.

  15. Efficacy of Plant-Derived and Synthetic Compounds on Clothing as Repellents Against Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae)

    Science.gov (United States)

    2012-01-01

    efÞcacy of the repellent deet against Aedes aegypti . J. Am. Mosq. Control Assoc. 14: 178Ð182. Robbins, P. J., and M. G. Cherniack. 1986. Review of...VECTOR CONTROL , PEST MANAGEMENT, RESISTANCE, REPELLENTS Efficacy of Plant-Derived and Synthetic Compounds on Clothing as Repellents Against Ixodes...4 Division of Vector-BorneDiseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention

  16. Larvicidal, adulticidal, repellency and smoke toxic efficacy of Ficus krishnae against Anopheles stephensi Liston and Culex vishnui group mosquitoes

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    Koyel Mallick Haldar

    2014-02-01

    Full Text Available Objective: To establish the plant Ficus krishnae as potential antimosquito agent. Methods: Larvicidal and adulticidal efficacy of ethyl acetate and methanol extracts of leaves of Ficus krishnae were evaluated against 3rd instar larvae and adults of Anopheles stephensi and Culex vishnui group mosquito for 24 h. Smoke toxicity test along with test for repellency on adult forms of the two mosquitoes were performed by the methanol extract. Results: The mortality rate varies in a dose dependent characteristic. The tests for larvicidal and adulticidal activity with both the solvent extracts showed significant efficiencies against the mosquitoes studied. The outcome of smoke toxicity test and repellency test were impressive. Conclusion: The study reveals that the solvent extracts of Ficus krishnae could be an effective natural alternative to get control over the mosquito population.

  17. Repellent efficacy of DEET, Icaridin, and EBAAP against Ixodes ricinus and Ixodes scapularis nymphs (Acari, Ixodidae).

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    Büchel, Kerstin; Bendin, Juliane; Gharbi, Amina; Rahlenbeck, Sibylle; Dautel, Hans

    2015-06-01

    Repellent efficacy of 10% EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester) and 10% Icaridin ((2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester)) were evaluated against 20% DEET (N,N-diethyl-3-methylbenzamide) in human subject trials against ticks. Responses of host-seeking nymphs of the European castor bean tick (Ixodes ricinus L.; Acari: Ixodidae) and the North American blacklegged tick (I. scapularis Say; Acari: Ixodidae) were compared. Tests were carried out according to the US-EPA standard protocol with ethanolic solutions of the active ingredients of repellents being applied to the forearm of 10 volunteers. The upward movement of ticks was monitored until repellent failure taking up to 12.5 h. Application of 20% DEET resulted in median complete protection times (CPT; Kaplan-Meier median) between 4 and 4.5 h, while 10% EBAAP yielded CPTs of 3.5-4h. No significant differences were found between the efficacies of two repellents nor between the two species tested. The median of the CPT of a 10% Icaridin solution was 5h in nymphs of I. scapularis, but 8h in those of I. ricinus (Prepellent activity against nymphs of the two Ixodes ticks with Icaridin demonstrating particularly promising results against I. ricinus. Future research should investigate whether similar results occur when adult Ixodes ticks or other tick species are tested.

  18. Rodent-repellent studies. I. Method for the evaluation of chemical repellents

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    Bellack, E.; DeWitt, J.B.

    1949-01-01

    A biological assay procedure and a method for the numerical expression of results have been devised for the determination of the repellency to rodents of different chemical compounds. The procedure is based upon the degree of acceptability of foods containing the candidate repellents,. and has been shown. to offer a rapid, reliable measure of repellent activIty.

  19. Efficacy of the repellent N,N-diethyl-3-methyl-benzamide (DEET) against tabanid flies on horses evaluated in a field test in Switzerland.

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    Herholz, C; Kopp, C; Wenger, M; Mathis, A; Wägeli, S; Roth, N

    2016-05-15

    Female tabanid flies (Diptera: Tabanidae) can be a serious nuisance for horses because of their painful bites during blood feeding. They also play a primary role in mechanical transmission of a lentivirus causing Equine Infectious Anemia (EIA), a virus that has spread within Europe in recent years. According to the European law for products intended for use as a repellent on horses (recreational and sport horses), a field test is mandatory to demonstrate sufficient repellency of such a substance against the specific target fly species, but currently no agreed protocols are available for testing of potential repellents. The aim of the present study was to establish a protocol for a field test to investigate the efficacy of N,N-diethyl-3-methyl-benzamide (DEET, Brum®, Huebeli-Stud Horse Care AG) in a 15-17% oil-water emulsion against tabanid flies on horses up to four hours. Between July and August 2015, four horses on three farms each were tested on two consecutive days in a cross-over design. The four horses on Farm A were used in the pre-test as well as in the main test. Two and a half hours after repellent application the horses were lunged until sweating. Tabanid fly infestations were both photographed and directly counted during five minutes 3 and 4h after repellent application on the right side of the horses in the area from the head to the flank, belly and first third of the foreleg. Without repellent application, up to 29 tabanid flies were counted on a horse, whereas the maximum for the repellent treated horses was four. In 50% of the horses treated with DEET there were no Tabanids observed (efficacy 100%), and in all horses the tabanid fly counts were lower than in the control horses with one exemption at 4h. The efficacy of the DEET repellent was at least 80% and 71% respectively, three or four hours after application (with a confidence level of 89%). A fly trap (Horse Pal) revealed the presence of the tabanid species Tabanus brominus and Haematopota

  20. Determination of the efficacy of two water repellents applied to granite

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    Rivas, T.

    1998-03-01

    Full Text Available We evaluated the efficacy of two water-repellents applied to three types of granitic rock widely used in building construction and restoration in Galicia (NW Spain. The depth of penetration of the water-repellents was determined by measuring capillary absorption by the treated rock. The efficacies of the water-repellent were evaluated in terms of two parameters characteristic of surface wet: water-rock contact angle and the time taken for absorption of microgroplets. The effects of the treatments on the rocks' surface color and permeability to water vapor were also determined. The results indicate that neither water-repellent effectively penetrates the rock surface, and both induce undesirably high reductions in vapor permeability. Notwithstanding, both agents effectively improved the rocks' resistance to surface wetting, without altering its surface color. Overall, determination of water-rock contact angle and the time taken for absorption of microdroplets, together with colorimetric characterization of the treated rock, constitutes an useful approach to evaluation of the effects of water-repellents on granitic rocks. Nonetheless, it should be borne in mind that the marked heterogeneity of this type of rock, and the associated mineralogy and dominant type of fissuration are sources of considerable variation in the measurement parameters.

    Se presentan los resultados de la aplicación de dos tratamientos hidrofugantes a tres rocas graníticas ampliamente utilizadas en la construcción y restauración en Galicia. Se ha determinado la profundidad de penetración de los hidrofugantes a través de la absorción capilar, la eficacia de los tratamientos comparando dos parámetros relacionados con el mojado superficial (ángulo de contacto roca-agua y tiempo de absorción de microgotas, y las variaciones en el color y en la permeabilidad al vapor. Se comprueba que si bien ambos tratamientos penetran deforma muy escasa en las rocas graníticas y

  1. Efficacy of Thai herbal essential oils as green repellent against mosquito vectors.

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    Soonwera, Mayura; Phasomkusolsil, Siriporn

    2015-02-01

    Repellency activity of Thai essential oils derived from ylang ylang (Cananga odorata (Lamk.) Hook.f. & Thomson: Annonaceae) and lemongrass (Cymbopogon citratus (DC.) Stapf: Poaceae) were tested against two mosquito vectors, Aedes aegypti (L.) and Culex quinquefasciatus (Say). There were compared with two chemical repellents (DEET 20% w/w; Sketolene Shield(®) and IR3535, ethyl butylacetylaminopropionate 12.5% w/w; Johnson's Baby Clear Lotion Anti-Mosquito(®)). Each herbal repellent was applied in three diluents; coconut oil, soybean oil and olive oil at 0.33 μl/cm(2) on the forearm of volunteers. All herbal repellent exhibited higher repellent activity than IR3535 12.5% w/w, but lower repellent activity than DEET 20% w/w. The C. odorata oil in coconut oil exhibited excellent activity with 98.9% protection from bites of A. aegypti for 88.7±10.4 min. In addition, C. citratus in olive oil showed excellent activity with 98.8% protection from bites of C. quinquefasciatus for 170.0±9.0 min. While, DEET 20% w/w gave protection for 155.0±7.1-182.0±12.2 min and 98.5% protection from bites of two mosquito species. However, all herbal repellent provided lower repellency activity (97.4-98.9% protection for 10.5-88.7 min) against A. aegypti than C. quinquefasciatus (98.3-99.2% protection for 60-170 min). Our data exhibited that C. odorata oil and C. citratus oil are suitable to be used as green repellents for mosquito control, which are safe for humans, domestic animals and environmental friendly.

  2. Repellent efficacy of formic acid and the abdominal secretion of carpenter ants (Hymenoptera: Formicidae) against Amblyomma ticks (Acari: Ixodidae).

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    Falótico, Tiago; Labruna, Marcelo B; Verderane, Michele P; De Resende, Briseida D; Izar, Patrícia; Ottoni, Eduardo B

    2007-07-01

    Formic acid is a substance produced by some ants for defense, trail marking, and recruitment. Some animals are known to rub ants or other arthropods on parts of their plumage or fur to anoint themselves with released substances. A recent study with a semifree-ranging group of capuchin monkeys, Cebus apella L., in the Tietê Ecological Park, Sao Paulo, Brazil, an area of occurrence of the tick species Amblyomma cajennense (F.), revealed that "anting" with carpenter ants, Camponotus rufipes F. (Hymenoptera: Formicidae), occurs frequently, especially during the A. cajennense subadult season. Based on these observations, we tested the repellent effect of the formic acid and the ants themselves against A. cajennense and Amblyomma incisum Neumann nymphs, and Amblyomma parcum Aragdo adult ticks in the laboratory. The results revealed a significant repellent effect of formic acid and ant secretion, and a significant duration of the repellent effect. The results suggest that the anting behavior of capuchin monkeys, and other vertebrates, may be related with repellence of ticks and other ectoparasites.

  3. [Prevention with repellent in children].

    Science.gov (United States)

    Sorge, F

    2009-10-01

    Use of topical insect repellent is an important component in prophylaxis of arthropod bite vector borne diseases. Topical insect repellent are used in a three part management regimen, along with impregnated clothing and mosquito netting. Parental training for efficacious and secure use of repellents for their children is essential part of a successful strategy to combat Lyme borreliosis, dengue fever, Chikungunya, West Nile virus infection and malaria, amongst children, according to local epidemiological risks. Rational repellent prescription for a child must take into account age, active substance concentration, topical substance tolerance, nature and surface of the skin to protect, number of daily applications, and the length of use in a benefit-risk ratio assessment perspective. The 4 currently repellents recommended by Whopes (Who) for their long lasting efficacy and patient tolerance are: 1) Citriodiol (PMD), 2) DEET, 3) Icaridine (KB3023), and 4) IR3535. In field trials the minimum required concentration of each four of these agents to be effective for 3 hours against most arthropods is 20% (in cream, roll-on or spray vehicle). Described side effects of these agents are mild, being limited to local irritative dermatitis and allergy. The risk of severe side effects has been related to DEET misused and neurotoxicity. The international recommendations concerning utilization of topical repellent amongst children for prophylaxis of arthropod borne diseases is concerning short term usage (several weeks). But the use of repellent is sub chronic or chronic amongst the majority of children living in subtropical regions where these vector borne diseases are endemic. And toxicity of topical repellent when used sub-chronically and chronically is not well studied in pediatric age groups. Taking into account these considerations, the current recommendations of the French Group of Tropical Paediatrics are to teach the parents of children who live in arthropod vector disease

  4. The repellent efficacy of eleven essential oils against adult Dermacentor reticulatus ticks.

    Science.gov (United States)

    Štefanidesová, Katarína; Škultéty, Ľudovít; Sparagano, Olivier A E; Špitalská, Eva

    2017-08-01

    Dermacentor reticulatus ticks are among the most important arthropod vectors of zoonotic disease agents in Europe. Eleven essential oils, namely basil (Ocimum basilicum), bergamot (Citrus bergamia), clove bud (Syzygium aromaticum), citronella (Cymbopogon winterianus), creeping thyme (Thymus serpyllum), lavender (Lavandula angustifolia), lemon-scented gum (Corymbia citriodora), marjoram (Origanum majorana), peppermint (Mentha piperita), spearmint (M. spicata), and red thyme (Thymus vulgaris) were tested for repellency against adult D. reticulatus ticks at concentrations of 1 and 3%. Clove bud, creeping thyme and red thyme essential oils were the most efficient - repelling 83, 82 and 68% of ticks when diluted to 3%, respectively. The mixture of creeping thyme and citronella containing 1.5% of each showed higher repellency (91%) than individual essential oils at the concentration of 3%. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. ANALYSIS AND APPLIED STUDY OF DYNAMIC CHARACTERISTICS OF CHAOTIC REPELLER IN COMPLICATED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    MA Jun-hai; REN Biao; CHEN Yu-shu

    2005-01-01

    Fractal characters and fractal dimension of time series created by repeller in complicated system were studied and the time series were reconstructed by applying the theory of phase space reconstruction for chaotic time series. The influence of zero-mean treatment, Fourier filter on prediction for time series were studied. The choice of prediction sample affects the relative error and the prediction length which were also under good concern. The results show that the model provided here are practical for the modeling and prediction of time series created by chaotic repellers. Zero-mean treatment has changed prediction result quantitatively for chaotic repeller sample data. But using Fourier filter may decrease the prediction precision. This is theoretical and practical for study on chaotic repeller in complicated system.

  6. Efficacy of commercially available ultrasonic pest repellent devices to affect behavior of bed bugs (Hemiptera: Cimicidae).

    Science.gov (United States)

    Yturralde, K M; Hofstetter, R W

    2012-12-01

    Little is known about the potential for acoustic communication in bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), or the use of sound as cues in host location, although many hemipterans are known to communicate with sound. Most behavioral research has focused on bed bug pheromones that are used in aggregation and as alarm signals. We investigated the influence of sound as a deterrent and as an attractant, either of which could ultimately be used to monitor and control bed bugs. Female bed bugs were tested in two-choice tests with four different commercially available ultrasonic repellent devices. We found that female bed bugs were equally likely to occur in arenas with or without sound produced by ultrasonic devices. These devices did not repel or attract bed bugs during choice trials. However, more bed bugs preferred the middle corridor between the test (sound) and control (no sound) arenas when the sound devices were played. Bed bugs were also more likely to exit the middle corridor during control trials compared with treatment trials with ultrasonic devices. Our results confirm that commercial devices producing ultrasound are not a promising tool for repelling bed bugs.

  7. Studies toward the synthesis of the shark repellent pavoninin-5.

    Science.gov (United States)

    Williams, John R; Chai, Deping; Gong, Hua; Zhao, Wei; Wright, Dominic

    2002-12-01

    Sharks are the most dangerous predators of people in the sea, resulting in people being mauled and killed each year. A shark repellent could help to diminish this danger. The aglycone of the shark repellent pavoninin-5, (25R)-cholest-5-en-3beta,15alpha,26-triol (5a), was synthesized from diosgenin (9). Removing mercury from the Clemmensen reduction of 9 gave a higher yield of (25R)-cholest-5-en-3beta,16beta,26-triol, 10a, and was also more environmentally friendly. Attempted methods for the transposition of the C-16beta hydroxyl to the 15alpha position are described. A successful method for this transposition via the 15alpha-hydroxy-16-ketone, 8a, using the Barton deoxygenation reaction on the 16-alcohol 14b, is reported.

  8. [Efficacy studies].

    Science.gov (United States)

    Pedro-Botet, Juan; Flores-Le Roux, Juana A

    2014-07-01

    Pravafenix(®) is a fixed-dose combination of 40mg of pravastatin and 160 mg of fenofibrate. The rationale behind the use of Pravafenix(®) is based on the increased residual cardiovascular risk observed in high risk patients with hypertriglyceridemia and/or low HDL cholesterol levels despite treatment with statins in monotherapy. In this article, we review the available evidence on the clinical efficacy of Pravafenix(®), which shows complementary benefits in the overall lipid profile of high risk patients with mixed dyslipidemia not controlled with 40-mg pravastatin or 20-mg simvastatin. Copyright © 2014 Sociedad Española de Arteriosclerosis y Elsevier España, S.L. All rights reserved.

  9. Preliminary study on mosquito repellent and mosquitocidal activities of Ocimum gratissimum (L.) grown in eastern Nigeria.

    Science.gov (United States)

    Oparaocha, Evangeline T; Iwu, Iraneus; Ahanakuc, J E

    2010-03-01

    The study examined the mosquito-repellent and mosquitocidal activities of the volatile oil of Ocimum gratissimum at three different locations (World Bank Estate, Ihitte and Umuekunne) in Imo State, eastern Nigeria, with the purpose of sourcing for mosquito repellent that is cheap, abundant, environment and user-friendly. Four different lotions; 20% (v/v) and 30% (v/v) concentrations each of the extracted volatile oil in two natural oil bases (olive and palm kernel) were made and six volunteered human baits were used to evaluate the mosquito repellent and mosquitocidal activities of the stock materials at the three different centres from September to November 2008. Topical application of each of the four different lotions significantly (p mosquitoes in all the three locations tested. The 30% (v/v) concentration in olive oil base exhibiting highest average percentage repellencies of 97.2, 95.7 and 96.3% at World Bank Estate, Ihitte and Umuekunne centres respectively while the 20% (v/v) concentration in palm kernel oil base had the least repellency of 36.3, 41.6 and 36.3%, respectively. The other two formulations had values ranging from 67.8 to 80% in the three locations. The 30% (v/v) concentration in both olive and palm kernel oil bases afforded all night protection against mosquito bites in all the centres, and demonstrated fast knockdown and paralyzing effect on few mosquitoes at the urban centre (World Bank Estate). The study confirms that O. gratissimum grown in eastern Nigeria has mosquito-repellent and mosquitocidal potentials and the formulations could be used to reduce human-mosquito contacts and hence mosquito-borne diseases and irritations caused by their bites.

  10. Ethnobotanical study of some of mosquito repellent plants in north-eastern Tanzania

    Directory of Open Access Journals (Sweden)

    Tenu Filemoni

    2008-08-01

    Full Text Available Abstract Background The use of plant repellents against nuisance biting insects is common and its potential for malaria vector control requires evaluation in areas with different level of malaria endemicity. The essential oils of Ocimum suave and Ocimum kilimandscharicum were evaluated against malaria vectors in north-eastern Tanzania. Methodology An ethnobotanical study was conducted at Moshi in Kilimanjaro region north-eastern Tanzania, through interviews, to investigate the range of species of plants used as insect repellents. Also, bioassays were used to evaluate the protective potential of selected plants extracts against mosquitoes. Results The plant species mostly used as repellent at night are: fresh or smoke of the leaves of O. suave and O. kilimandscharicum (Lamiaceae, Azadirachta indica (Meliaceae, Eucalyptus globules (Myrtaceae and Lantana camara (Verbenaceae. The most popular repellents were O. kilimandscharicum (OK and O. suave (OS used by 67% out of 120 households interviewed. Bioassay of essential oils of the two Ocimum plants was compared with citronella and DEET to study the repellence and feeding inhibition of untreated and treated arms of volunteers. Using filter papers impregnated with Ocimum extracts, knockdown effects and mortality was investigated on malaria mosquito Anopheles arabiensis and Anopheles gambiae, including a nuisance mosquito, Culex quinquefasciatus. High biting protection (83% to 91% and feeding inhibition (71.2% to 92.5% was observed against three species of mosquitoes. Likewise the extracts of Ocimum plants induced KD90 of longer time in mosquitoes than citronella, a standard botanical repellent. Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella. Conclusion The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results

  11. Lousicidal, ovicidal and repellent efficacy of some essential oils against lice and flies infesting water buffaloes in Egypt.

    Science.gov (United States)

    Khater, Hanem F; Ramadan, Mohamed Y; El-Madawy, Reham S

    2009-10-14

    The lousicidal and repellent effects of five essential oils were investigated for the first time against the buffalo louse, Haematopinus tuberculatus, and flies infesting water buffaloes in Qalyubia Governorate, Egypt. For the in vitro studies, filter paper contact bioassays were used to test the oils and their lethal activities were compared with that of d-phenothrin. Four minutes post-treatment, the median lethal concentration, LC50, values were 2.74, 7.28, 12.35, 18.67 and 22.79% for camphor (Cinnamomum camphora), onion (Allium cepa), peppermint (Mentha piperita), chamomile (Matricaria chamomilla) and rosemary oils (Rosmarinus officinalis), respectively, whereas for d-phenothrin, it was 1.17%. The lethal time (50) (LT50) values were 0.89, 2.75, 15.39, 21.32, 11.60 and 1.94 min after treatment with 7.5% camphor, onion, peppermint, chamomile, rosemary and d-phenothrin, respectively. All the materials used except rosemary, which was not applied, were ovicidal to the eggs of H. tuberculatus. Despite the results of the in vitro assays, the in vivo treatments revealed that the pediculicidal activity was more pronounced with oils. All treated lice were killed after 0.5-2 min, whereas with d-phenothrin, 100% mortality was reached only after 120 min. The number of lice infesting buffaloes was significantly reduced 3, 6, 4, 6 and 9 days after treatment with camphor, peppermint, chamomile, onion, and d-phenothrin, respectively. Moreover, the oils and d-phenothrin significantly repelled flies, Musca domestica, Stomoxys calcitrans, Haematobia irritans and Hippobosca equina, for 6 and 3 days post-treatment, respectively. No adverse effects were noted on either animals or pour-on operators after exposure to the applied materials. Consequently, some Egyptian essential oils show potential for the development of new, speedy and safe lousicides and insect repellents for controlling lice and flies which infest water buffaloes.

  12. Water repellency, plants, agriculture abandonment and fire in citrus plantations. The Canyoles river watershed study site

    Science.gov (United States)

    Cerdà, Artemi; Jordán, Antonio; Doerr, Stefan Helmut

    2017-04-01

    agriculture soil managed with tillage is hydrophilic, that the use of herbicides trigger a patchy and slight presence of hydrophobicity, that the growth of vegetation reached the highest water repellency degree with a patch distribution of the water repellency, and finally the fire reduced the surface water repellency and changes the spatial pattern. This study aims to fulfil the gap of a sampling strategy that will help the scientist to characterize the soil water repellency with a uniform and standard procedure and protocol. The results show the importance of the management to control the soil repellency (Bodí et al., 2012a) and the importance of the fire and ash and the water repellency (Bodí et al., 2012b; Dlapa et al., 2013; Benito Rueda et al., 2016). Acknowledgements The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n[U+25E6] 603498 (RECARE project) and the CGL2013- 47862-C2-1-R and CGL2016-75178-C2-2-R national research projects. References Alanís, N., Hernández-Madrigal, V. M., Cerdà, A., Muñoz-Rojas, M., Zavala, L. M., & Jordán, A. (2016). Spatial gradients of intensity and persistence of soil water repellency under different forest types in central mexico. Land Degradation and Development, doi:10.1002/ldr.2544 Benito Rueda, E., M. Rodríguez-Alleres, and E. Varela Teijeiro. 2016. Environmental Factors Governing Soil Water Repellency Dynamics in a Pinus Pinaster Plantation in NW Spain. Land Degradation and Development 27 (3): 719-728. doi:10.1002/ldr.2370. Bodí, M. B., A. Cerdà, J. Mataix-Solera, and S. H. Doerr. 2012a. Water Repellency in Forest Soils Affected by Fires and Agricultural Soils with Different Agricultural Management and Abandonment. Cuadernos De Investigacion Geografica 38 (2): 53-74. Bodí, M. B., S. H. Doerr, A. Cerdà, and J. Mataix-Solera. 2012b. Hydrological Effects of a Layer of Vegetation Ash on Underlying Wettable and Water Repellent

  13. A low-cost repellent for malaria vectors in the Americas: results of two field trials in Guatemala and Peru

    Directory of Open Access Journals (Sweden)

    Sihuincha Moisés

    2007-08-01

    Full Text Available Abstract Background The cost of mosquito repellents in Latin America has discouraged their wider use among the poor. To address this problem, a low-cost repellent was developed that reduces the level of expensive repellent actives by combining them with inexpensive fixatives that appear to slow repellent evaporation. The chosen actives were a mixture of para-menthane-diol (PMD and lemongrass oil (LG. Methods To test the efficacy of the repellent, field trials were staged in Guatemala and Peru. Repellent efficacy was determined by human-landing catches on volunteers who wore the experimental repellents, control, or 15% DEET. The studies were conducted using a balanced Latin Square design with volunteers, treatments, and locations rotated each night. Results In Guatemala, collections were performed for two hours, commencing three hours after repellent application. The repellent provided >98% protection for five hours after application, with a biting pressure of >100 landings per person/hour. The 15% DEET control provided lower protection at 92% (p 46 landings per person/hour. The 20% DEET control provided significantly lower protection at 64% (p Conclusion In both locations, the PMD/LG repellent provided excellent protection up to six hours after application against a wide range of disease vectors including Anopheles darlingi. The addition of fixatives to the repellent extended its longevity while enhancing efficacy and significantly reducing its cost to malaria-endemic communities.

  14. Preliminary study on mosquito repellent and mosquitocidal activities of Ocimum gratissimum (L. grown in eastern Nigeria

    Directory of Open Access Journals (Sweden)

    Evangeline T. Oparaocha

    2010-03-01

    Full Text Available Background & objectives: The study examined the mosquito-repellent and mosquitocidal activitiesof the volatile oil of Ocimum gratissimum at three different locations (World Bank Estate, Ihitteand Umuekunne in Imo State, eastern Nigeria, with the purpose of sourcing for mosquito repellentthat is cheap, abundant, environment and user-friendly.Methods: Four different lotions; 20% (v/v and 30% (v/v concentrations each of the extractedvolatile oil in two natural oil bases (olive and palm kernel were made and six volunteered humanbaits were used to evaluate the mosquito repellent and mosquitocidal activities of the stock materialsat the three different centres from September to November 2008.Results: Topical application of each of the four different lotions significantly (p <0.05 reduced thebiting rate of mosquitoes in all the three locations tested. The 30% (v/v concentration in olive oilbase exhibiting highest average percentage repellencies of 97.2, 95.7 and 96.3% at World BankEstate, Ihitte and Umuekunne centres respectively while the 20% (v/v concentration in palmkernel oil base had the least repellency of 36.3, 41.6 and 36.3%, respectively. The other twoformulations had values ranging from 67.8 to 80% in the three locations. The 30% (v/vconcentration in both olive and palm kernel oil bases afforded all night protection against mosquitobites in all the centres, and demonstrated fast knockdown and paralyzing effect on few mosquitoesat the urban centre (World Bank Estate.Interpretation & conclusion: The study confirms that O. gratissimum grown in eastern Nigeriahas mosquito-repellent and mosquitocidal potentials and the formulations could be used to reducehuman-mosquito contacts and hence mosquito-borne diseases and irritations caused by their bites.

  15. Assessing the efficacy of candidate mosquito repellents against the background of an attractive source that mimics a human host

    NARCIS (Netherlands)

    Menger, D.J.; Loon, van J.J.A.; Takken, W.

    2014-01-01

    Mosquito repellents are used around the globe to protect against nuisance biting and disease-transmitting mosquitoes. Recently, there has been renewed interest in the development of repellents as tools to control the transmission of mosquito-borne diseases. We present a new bioassay for the accurate

  16. Assessing the efficacy of candidate mosquito repellents against the background of an attractive source that mimics a human host

    NARCIS (Netherlands)

    Menger, D.J.; Loon, van J.J.A.; Takken, W.

    2014-01-01

    Mosquito repellents are used around the globe to protect against nuisance biting and disease-transmitting mosquitoes. Recently, there has been renewed interest in the development of repellents as tools to control the transmission of mosquito-borne diseases. We present a new bioassay for the accurate

  17. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

    Directory of Open Access Journals (Sweden)

    Karel Van Roey

    2014-12-01

    Full Text Available Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the

  18. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

    Science.gov (United States)

    Van Roey, Karel; Sokny, Mao; Denis, Leen; Van den Broeck, Nick; Heng, Somony; Siv, Sovannaroth; Sluydts, Vincent; Sochantha, Tho; Coosemans, Marc; Durnez, Lies

    2014-12-01

    Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the epidemiological

  19. In vitro repellency of DEET against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum

    Science.gov (United States)

    Rhipicephalus sanguineus sensu lato and Amblyomma sculptum can parasite humans and domestic animals and are vectors of pathogens, including zoonoses. Repellents are an important tool of tick control. This study aimed to compare the efficacy of N,N-diethyl- 3-methylbenzamide (DEET), a standard repell...

  20. Prevention of tungiasis and tungiasis-associated morbidity using the plant-based repellent Zanzarin: a randomized, controlled field study in rural Madagascar.

    Directory of Open Access Journals (Sweden)

    Marlene Thielecke

    Full Text Available BACKGROUND: Tungiasis, a parasitic skin disease caused by the female sand flea Tunga penetrans, is a prevalent condition in impoverished communities in the tropics. In this setting, the ectoparasitosis is associated with important morbidity. It causes disfigurement and mutilation of the feet. Feasible and effective treatment is not available. So far prevention is the only means to control tungiasis-associated morbidity. METHODOLOGY: In two villages in Central Madagascar, we assessed the efficacy of the availability of closed shoes and the twice-daily application of a plant-based repellent active against sand fleas (Zanzarin in comparison to a control group without intervention. The study population was randomized into three groups: shoe group, repellent group and control group and monitored for ten weeks. The intensity of infestation, the attack rate and the severity of tungiasis-associated morbidity were assessed every two weeks. FINDINGS: In the repellent group, the median attack rate became zero already after two weeks. The intensity of the infestation decreased constantly during the observation period and tungiasis-associated morbidity was lowered to an insignificant level. In the shoe group, only a marginal decrease in the intensity of infestation and in the attack rate was observed. At week 10, the intensity of infestation, the attack rate and the severity score for acute tungiasis remained significantly higher in the shoe group than in the repellent group. Per protocol analysis showed that the protective effect of shoes was closely related to the regularity with which shoes were worn. CONCLUSIONS: Although shoes were requested by the villagers and wearing shoes was encouraged by the investigators at the beginning of the study, the availability of shoes only marginally influenced the attack rate of female sand fleas. The twice-daily application of a plant-based repellent active against sand fleas reduced the attack to zero and lowered

  1. Natural product studies of U.S. endangered plants: volatile components of Lindera melissifolia (Lauraceae) repel mosquitoes and ticks.

    Science.gov (United States)

    Oh, Joonseok; Bowling, John J; Carroll, John F; Demirci, Betul; Başer, K Hüsnü Can; Leininger, Theodor D; Bernier, Ulrich R; Hamann, Mark T

    2012-08-01

    The number of endangered plant species in the U.S. is significant, yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are vectors of significant pathogenic diseases of humans. Repellents are critical means of personal protection against biting arthropods and disease transmission. The essential oil and solvent extracts from Lindera melissifolia (Walt.) Blume (Lauraceae) (pondberry) drupes were gathered and analyzed by GC and GC-MS. The essential oil obtained from this endangered plant showed a significant dose dependent repellency of ticks and a moderate mosquito repellent effect while the subsequent hexanes extract was completely ineffective. Fractional freezing enriched the tick repellent components of the essential oil. Several known tick repellent components were recognized by the GC-MS comparison of the resulting fractions and β-caryophyllene, α-humulene, germacrene D and β-elemene warrant evaluations for tick repellency. Identifying pondberry as a potential renewable source for a broad spectrum repellent supports efforts to conserve similar U.S. endangered or threatened plant species.

  2. Natural product studies of U.S. endangered plants: Volatile components of Lindera melissifolia (Lauraceae) repel mosquitoes and ticks

    Science.gov (United States)

    Oh, Joonseok; Bowling, John J.; Carroll, John F.; Demirci, Betul; Başer, K. Hüsnü Can; Leininger, Theodor D.; Bernier, Ulrich R.; Hamann, Mark T.

    2014-01-01

    The number of endangered plant species in the U.S. is significant, yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are vectors of significant pathogenic diseases of humans. Repellents are critical means of personal protection against biting arthropods and disease transmission. The essential oil and solvent extracts from Lindera melissifolia (Walt.) Blume (Lauraceae) (pondberry) drupes were gathered and analyzed by GC and GC–MS. The essential oil obtained from this endangered plant showed a significant dose dependent repellency of ticks and a moderate mosquito repellent effect while the subsequent hexanes extract was completely ineffective. Fractional freezing enriched the tick repellent components of the essential oil. Several known tick repellent components were recognized by the GC–MS comparison of the resulting fractions and β-caryophyllene, α-humulene, germacrene D and β-elemene warrant evaluations for tick repellency. Identifying pondberry as a potential renewable source for a broad spectrum repellent supports efforts to conserve similar U.S. endangered or threatened plant species. PMID:22704653

  3. Assessing the efficacy of candidate mosquito repellents against the background of an attractive source that mimics a human host.

    Science.gov (United States)

    Menger, D J; Van Loon, J J A; Takken, W

    2014-12-01

    Mosquito repellents are used around the globe to protect against nuisance biting and disease-transmitting mosquitoes. Recently, there has been renewed interest in the development of repellents as tools to control the transmission of mosquito-borne diseases. We present a new bioassay for the accurate assessment of candidate repellent compounds, using a synthetic odour that mimics the odour blend released by human skin. Using DEET (N,N-diethyl-meta-toluamide) and PMD (p-menthane-3,8-diol) as reference compounds, nine candidate repellents were tested, of which five showed significant repellency to the malaria mosquito Anopheles gambiae sensu stricto (Diptera: Culicidae). These included: 2-nonanone; 6-methyl-5-hepten-2-one; linalool; δ-decalactone, and δ-undecalactone. The lactones were also tested on the yellow fever mosquito Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae), against which they showed similar degrees of repellency. We conclude that the lactones are highly promising repellents, particularly because these compounds are pleasant-smelling, natural products that are also present in human food sources. © 2014 The Royal Entomological Society.

  4. Efficacy comparison of the repellent between laboratories%实验室间的驱避剂药效对比研究

    Institute of Scientific and Technical Information of China (English)

    郑卫青; 柳小青; 马红梅; 陶卉英; 刘仰青; 陈超; 姜志宽

    2011-01-01

    目的 比较不同实验室对同一种蚊虫、同一种驱避剂的药效检测结果.方法 GB/T13917.9-2009农药登记用卫生杀虫剂室内药效试验与评价-驱避剂.结果 甲实验室检测的A、B驱避剂平均有效保护时间分别为5.75 h、4.25 h;乙实验室检测的A、B驱避剂平均有效保护时间分别为5.50 h、4.25 h.结论 实验室间的驱避药效试验结果没有显著性差异,乙实验室可以开展相关产品的药效评价.%Objective To compare the efficacy of repellent tested by two laboratories. Methods According to the method of GB/T13917.9 -2009. Results The average effectively repellent time of repellet A and B tested by No. 1 laboratory were 5.75 and 4. 25 h respectively. The average effectively repellent time of repellet A and B tested by No. 2 laboratory were 5.50 and 4. 25 h respectively. Conclusion There is no statistical difference in the efficacy of repellent tested by two laboratories.

  5. Effectiveness of Gel Repellents on Feral Pigeons

    Directory of Open Access Journals (Sweden)

    Birte Stock

    2013-12-01

    Full Text Available Millions of feral pigeons (Columba livia live in close association with the human population in our cities. They pose serious health risks to humans and lead to high economic loss due to damage caused to buildings. Consequently, house owners and city authorities are not willing to allow pigeons on their buildings. While various avian repellents are regularly introduced onto the market, scientific proof of efficacy is lacking. This study aimed at testing the effectiveness of two avian gel repellents and additionally examined their application from animal welfare standpoint. The gels used an alleged tactile or visual aversion of the birds, reinforced by additional sensory cues. We mounted experimental shelves with the installed repellents in a pigeon loft and observed the behavior of free-living feral pigeons towards the systems. Both gels showed a restricted, transient repellent effect, but failed to prove the claimed complete effectiveness. Additionally, the gels’ adhesive effect remains doubtful in view of animal welfare because gluing of plumage presents a risk to feral pigeons and also to other non-target birds. This study infers that both gels lack the promised complete efficacy, conflict with animal welfare concerns and are therefore not suitable for feral pigeon management in urban areas.

  6. Microencapsulated citronella oil for mosquito repellent finishing of cotton textiles.

    Science.gov (United States)

    Specos, M M Miró; García, J J; Tornesello, J; Marino, P; Vecchia, M Della; Tesoriero, M V Defain; Hermida, L G

    2010-10-01

    Microcapsules containing citronella essential oil were prepared by complex coacervation and applied to cotton textiles in order to study the repellent efficacy of the obtained fabrics. Citronella released from treated textiles was indirectly monitored by the extractable content of its main components. Repellent activity was assessed by exposure of a human hand and arm covered with the treated textiles to Aedes aegypti mosquitoes. Fabrics treated with microencapsulated citronella presented a higher and longer lasting protection from insects compared to fabrics sprayed with an ethanol solution of the essential oil, assuring a repellent effect higher than 90% for three weeks. Complex coacervation is a simple, low cost, scalable and reproducible method of obtaining encapsulated essential oils for textile application. Repellent textiles were achieved by padding cotton fabrics with microcapsules slurries using a conventional pad-dry method. This methodology requires no additional investment for textile finishing industries, which is a desirable factor in developing countries.

  7. Repellent Action of Neem (Azadirachta indica) Seed Oil Cream ...

    African Journals Online (AJOL)

    Nekky Umera

    potential of neem seed oil cream as mosquito repellent particularly at higher ... In the present study, neem Seed oil extracted from Azadirachta indica plant .... repellency was in two phases, first to determine the repellency properties of.

  8. Evaluation of biological and chemical insect repellents and their potential adverse effects.

    Science.gov (United States)

    Semmler, Margit; Abdel-Ghaffar, Fathy; Schmidt, Jürgen; Mehlhorn, Heinz

    2014-01-01

    Plant extracts, particularly plant oils, had been used and were still in use as repellents against mosquitoes. Some of them (e.g., lavender, geraniol, and citriodiol) have been notified by the European Commission as active substances to be used in repellents, which are categorized as biocides in product type 19. In the literature, it is known that these substances must be added to repellent products in high concentrations (e.g., 20% and more) in order to reach repellent efficacy. Therefore, the question arose whether they also have repellent effects if they were added as fragrances at low concentrations of 0.25 or 1% to registered active substances in order to obtain a better scent of this product. In the present study, the repellent effects of 0.25 and 1% additions of 15 plant extracts (citronellol, cinerol, citral, menthol, linalyl acetate, Eucalyptus citriodora, Eucalyptus globulus, Cymbopogon nardus, lilac, sandalwood, Vitex agnus castus, rosewood, lavender, geraniol, and paramenthan diol) when exposed on skin to hungry Aedes aegypti mosquitoes. These experiments showed that there was no repellent effect in any of these compounds even when the test was done already 10 min after distributing any of the compounds onto the hands of volunteers. These experiments have proven that these 15 compounds do not produce repellent effects as long as they are used in low concentrations of 0.25 or 1% as fragrances to ameliorate the odor of a notified repellent that is brought onto the skin.

  9. Sharks senses and shark repellents.

    Science.gov (United States)

    Hart, Nathan S; Collin, Shaun P

    2015-01-01

    Despite over 70 years of research on shark repellents, few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed. In large part, this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks. However, the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal. Here, we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents. We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems. We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices, in particular, the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology.

  10. 羟哌酯的合成及其防蚊效果研究%Synthesis and repellent efficacy test of bayrepel

    Institute of Scientific and Technical Information of China (English)

    郑剑; 陈超; 谭伟龙; 王天桃

    2012-01-01

    Objective To synthesis repellent bayrepel and evaluate its repellency against mosquitoes. Methods Bayrepel was synthesized from 2-hydroxyethyl pyridine by reaction with chloride carboxylic acid 1-methylpropyl ester. Efficacy test of bayrepel was conducted by GB/T 17322. 10 - 1998. Results Bayrepel was prepared and the mole yield was 80% ; laboratory tests showed that the protection time of 20% bayrepel was 11 h against Aedes albopic-tus with the quantity of 0. 24 mg/cm2 , field tests showed that the protection time of 20% bayrepel was 9 h against mosquitoes. Conclusion Bayrepel is an good repellent with the property of highly stable,more effective,low toxici-ty,low cost.it has a good prospect for protection against mosquitoes.%目的 合成羟哌酯并测定其药效.方法 2-羟乙基哌啶和氯甲酸仲丁酯反应制备羟哌酯,按照GB/T 13917.9-2009方法对其进行实验室和现场药效测试.结果 2-羟乙基哌啶和氯甲酸仲丁酯反应制备羟哌酯,摩尔收率为82%;实验室药效测试20%羟哌酯0.240 mg/cm2剂量,对白纹伊蚊有效保护时间为11h,现场应用对蚊虫有效保护时间为9h.结论 羟哌酯化学性质稳定,驱蚊效果好,使用安全,生产成本低,作为防蚊驱避剂具有很好的应用前景.

  11. Comparative Study of Four Membranes for Evaluation of New Insect/Arthropod Repellents Using Aedes aegypti

    Science.gov (United States)

    2008-01-01

    test system, and (Armed Forces Pest Management Board. 1996) repellent potencial of the 3D pharmacophore- bascd newly designed and synthesized ten...ethyl- hexyl ester) Repellent test system: A modified inz:itro rest system was used to evaluate the potencial membrane altematives as shown in Fig. 1

  12. Investigation on Efficacy of BAAPE in Mosquito Repellent Cosmetics%驱蚊酯在个人护理化妆品中的药效探讨

    Institute of Scientific and Technical Information of China (English)

    崔彬

    2014-01-01

    目前在个人护理品和家居产品领域,驱蚊产品以实现驱蚊功效为主要卖点,很少考虑对皮肤的保护和护理。因此,在不影响蚊虫驱避效果的基础上考虑产品对皮肤的护理功效是一个重要的开发课题。研究通过选择和调整驱蚊产品的配方原料,从而使产品兼具良好的护肤作用和驱蚊效果,并对成品在中国南北方不同地区的驱蚊功效进行了全面的测试。%The caring and protecting functions of mosquito repellent products for skin are seldom considered in personal care and household products categories. So,it is an important issue for cosmetic R&D engineer to ensure this kind of products also having skin care efficacy. Here,by selecting unique ingredients and modifying the composition of formula,the products with both skin caring and mosquito repellent effects were obtained and tested in different areas of China.

  13. Natural product studies of U.S. endangered plants: Volatile components of Lindera melissifolia (Lauraceae) repel mosquitoes and ticks

    Science.gov (United States)

    Joonseok Oh; John J. Bowling; John F. Carroll; Betul Demirci; K. Hüsnü Can Baser; Theodor D. Leininger; Ulrich R. Berniere; Mark T. Hamann

    2012-01-01

    The number of endangered plant species in the U.S. is significant, yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are vectors of significant pathogenic diseases of humans. Repellents are critical means of personal protection against biting arthropods and disease transmission. The essential oil and solvent extracts from ...

  14. [Comparative behaviour studies in horses infested with flying insects treated with insecticide or repellent substances].

    Science.gov (United States)

    Sünder, Ulrich; Moors, Eva; Hagemann, Kristina; Gauly, Matthias

    2011-01-01

    The aim of this study was to estimate the effects of flying insects (Order Diptera) on the behaviour of grazing horses in relation to the use of insecticide and repellent substances. The investigations were done between June and August in 2008 in 3 periods of 7 days each. As insecticide and repellent two substances were used: "Well-care emulsion" (Co. Essex Tierarznei, München, GER) containing Permethrin and "Bremsen-Frei-Plus" (Co. Dr. Schaette AG, Bad Waldsee, GER) based on etheric oils. Both groups were compared with a non treated control group in a crossover-design. Each group (n = 3-5) was used alternately as control and treatment group. Several climate parameters were taken during the study. Furthermore, the number of insects per animal was estimated at certain times. Once per observation period insects were caught using Malaise traps and differentiated by species. The proportion of horse relevant species of the genera Diptera, especially Culex pipiens and Musca autumnalis, caught was 9% on an average. There was no correlation between the number of Tabanidae caught in the Malaise traps and the number observed near by the horses. Behaviour parameters like tailswishing, headshaking, stamping, skintwitching, snapping at the body, and moving were observed more frequently with increasing insect infestation. When horses were infested with a high number of flying insects, feeding activity was significant lower, whereas locomotion activity was significant higher. Both substances had positive effects for about 50 hours after application with no apparent difference between the substances. However, a lower frequency of headshaking and tailswishing could be observed in the Permethrin treated horses.

  15. Prevention of infectious tick-borne diseases in humans: Comparative studies of the repellency of different dodecanoic acid-formulations against Ixodes ricinus ticks (Acari: Ixodidae

    Directory of Open Access Journals (Sweden)

    Dautel Hans

    2008-04-01

    Full Text Available Abstract Background Ticks of the species Ixodes ricinus are the main vectors of Lyme Borreliosis and Tick-borne Encephalitis – two rapidly emerging diseases in Europe. Repellents provide a practical means of protection against tick bites and can therefore minimize the transmission of tick-borne diseases. We developed and tested seven different dodecanoic acid (DDA-formulations for their efficacy in repelling host-seeking nymphs of I. ricinus by laboratory screening. The ultimately selected formulation was then used for comparative investigations of commercially available tick repellents in humans. Methods Laboratory screening tests were performed using the Moving-object (MO bioassay. All test formulations contained 10% of the naturally occurring active substance DDA and differed only in terms of the quantitative and qualitative composition of inactive ingredients and fragrances. The test procedure used in the human bioassays is a modification of an assay described by the U.S. Environmental Protection Agency and recommended for regulatory affairs. Repellency was computed using the equation: R = 100 - NR/N × 100, where NR is the number of non-repelled ticks, and N is the respective number of control ticks. All investigations were conducted in a controlled laboratory environment offering standardized test conditions. Results All test formulations strongly repelled nymphs of I. ricinus (100-81% protection as shown by the MO-bioassay. The majority of ticks dropped off the treated surface of the heated rotating drum that served as the attractant (1 mg/cm2 repellent applied. The 10% DDA-based formulation, that produced the best results in laboratory screening, was as effective as the coconut oil-based reference product. The mean protection time of both preparations was generally similar and averaged 8 hours. Repellency investigations in humans showed that the most effective 10% DDA-based formulation (~1.67 mg/cm2 applied strongly avoided the

  16. Study on water-repellent and oil-repellent finishing process of fabric%织物拒水拒油整理工艺探讨

    Institute of Scientific and Technical Information of China (English)

    黄小华; 石小奕; 赵堃

    2012-01-01

    Water repellent agents commonly used are silicones and fluorochemieals, but fluoroehemicals a gents impart both water repellency and oil repcllency to fabrics for meeting people's demand on muhi functional textiles. In this paper, TG-581 water and oil repellent agent,as a fluorochemical,was used to finish four kinds of fabrics. This paper discusses the effect of various factors, like the concentration of water and oil repellent agent, pH value of solution,dry temperature,cure temperature,cure time on the water and oil repellent performance of fabrics, so as to provide reference for determining the optimum water and oil repellent finishing process conditions.%目前常用的拒水剂主要是有机硅化合物和有机氟化合物,但有机氟化合物可同时赋予整理织物拒水、拒油性能,可满足人们对多功能纺织品的需求.本文使用含氟化合物TG-581拒水拒油整理剂对4种织物进行整理.文章探讨了整理剂质量浓度、整理液pH值、烘干温度、焙烘温度、焙烘时间等工艺因素对拒水拒油性能的影响,从而为确定拒水拒油整理最佳工艺条件提供参考.

  17. A double-blinded, placebo-controlled trial of garlic as a mosquito repellant: a preliminary study.

    Science.gov (United States)

    Rajan, T V; Hein, M; Porte, P; Wikel, S

    2005-03-01

    The hypothesis that the ingestion of garlic provides protection against bloodsucking pests such as mosquitoes was investigated using a randomized, double-blinded, placebo-controlled crossover study. Subjects were asked to consume either garlic (one visit) or a placebo (the other visit). They were then exposed to laboratory-reared Aedes aegypti (Linnaeus) (Diptera: Culicidae). The numbers of mosquitoes that did not feed on the subjects, the number of mosquito bites, the weights of the mosquitoes after feeding and the amounts of blood ingested were determined. The data did not provide evidence of significant systemic mosquito repellence. A limitation of the study is that more prolonged ingestion of garlic may be needed to accomplish repellence.

  18. Studies on the Insecticidal and Repellent Properties of the Seed Extract of Tephrosia Purpurea (LINN Pers

    Directory of Open Access Journals (Sweden)

    B. N. Saxena

    1974-04-01

    Full Text Available Laboratory and field trials were conducted to find out the insecticidal and repellent properties of petroleum ether extract of the seeds of Tephrosia purpurea. In laboratory trials contact toxicity of the extract was assessed against land leeches, houseflies, mosquitoes, rice weevil and flour beetle. In field trials, the repellency of the extract was assessed against land leeches, mosquitoes and simulium flies. In laboratory trials, the dosage required for 100 per cent mortality was 0.0005 gm/cm/sup 2/ for land leeches, 0.0157 gm/cm/sup 2/ for flour beetle. In field trials, the extract was found to be repellent against land leeches for 5 hours, mosquitoes for 4 hours and simulium flies for 5 hours.

  19. Study of water-repellent treatments applied on limestone from Andalusian Cathedrals

    Directory of Open Access Journals (Sweden)

    Villegas, R.

    1991-09-01

    Full Text Available Five types of stone used in Andalusian Cathedrals have been treated with different water-repellent treatments, to evaluate the effects of this products. The stones studied are limestone, calcarenite and dolomite; the products applied are organosilicones and acrylics. In this work properties related with water access and movement through the stone have been measured and compared their values before and after the application of the treatments.

    Se han tratado varios tipos de piedra utilizados en Catedrales Andaluzas con diversos productos hidrófugos, con el fin de evaluar las características conferidas por los mismos. Los tipos de piedra son de naturaleza caliza, calcarenitas y dolomías; los productos son organosilícicos y acrílicos. En este trabajo se han medido las propiedades relacionadas con el acceso y movimiento de agua en la piedra, comparándose sus valores antes y después de la aplicación del tratamiento.

  20. Efficacy of topical mosquito repellent (picaridin) plus long-lasting insecticidal nets versus long-lasting insecticidal nets alone for control of malaria : A cluster randomised controlled trial

    NARCIS (Netherlands)

    Sluydts, V.; Durnez, L.; Heng, S.; Gryseels, C.; Canier, L.; Kim, S.; Van Roey, K.; Kerkhof, K.; Khim, N.; Mao, S.; Menard, D.; Coosemans, M.

    2016-01-01

    Background Although effective topical repellents provide personal protection against malaria, whether mass use of topical repellents in addition to long-lasting insecticidal nets can contribute to a further decline of malaria is not known, particularly in areas where outdoor transmission occurs. We

  1. 民用飞机风挡排雨液选择设计初探%The Study of windshield rain repellent fluid choosing for civil aircraft

    Institute of Scientific and Technical Information of China (English)

    白穆; 霍西恒

    2016-01-01

    This paper analyzed and studied the rain repellent fluid choosing for civil aircraft; summarized the design improvement of rain repellent fluid choosing for civil aircraft.%本文对民用飞机风挡排雨液选择进行了初步分析与研究,给出风挡排雨液选择优化设计概述。

  2. Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes

    Science.gov (United States)

    DeWitt, J.B.; Bellack, E.; Welch, J.F.

    1953-01-01

    Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

  3. Insect Repellent Properties of Melaleuca alternifolia

    OpenAIRE

    Mohamad Adib Bin Edris; Awang Soh Yusuff Mamat; Muhammad Shahzad Aslam; Muhammad Syarhabil Ahmad

    2016-01-01

    The aim of this study is to compare the use of plant-based insect repellents that are environment friendly with the use of insect repellents based on chemical substances which can be harmful to the environment and human health. The plant studied here is "tea tree"; its scientific name is Melaleuca alternifolia. Essential oil from this plant is extracted by steam distillation method. Based on the previous research, tea tree oil has antimicrobial, antifungal, anti-inflammatory, and insect repel...

  4. Evaluation of Repellency Effect of Essential Oils of Satureja khuzestanica (Carvacrol, Myrtus communis (Myrtle, Lavendula officinalis and Salvia sclarea using Standard WHO Repellency Tests.

    Directory of Open Access Journals (Sweden)

    Mohammad Hassan Kayedi

    2014-06-01

    Full Text Available Using special lotions and repellent sprays on skin is one of the effective methods to prevent Arthropods biting which was verified in this study.Essential oils of four plants (Satureja khuzestanica, Salvia sclarea, Lavendula officinalis and Myrtus communis were separately extracted by Clevenger used hydro distillation method. Then separated solutions with 10%, 20% and 40% concentrations of essential oils of plants in 99.6 % ethanol were prepared. WHO guidelines for efficacy testing of mosquito repellents for human skin were used on different concentrations of essential oils of plants, traditional repellents (DEET, 50% and 33% as positive control, and ethanol 99.6% and naked hands as negative controls.In negative control groups, the number of bits were comparable (P= 0.42 and had decreasing time trends (naked hands P= 0.011, ethanol P< 0.001. In all time points, minimum bites were observed in traditional repellents and it was significantly less than the other groups (P< 0.001. The time trend in the number of bites in the other groups was positive and showed minimum number of bites in time zero in all groups. We also found that the concentration of repellents had association with the number of bites. The maximum and minimum numbers of bites were observed with 10% and 40% concentrations respectively in all groups.Essential oils of Salvia sclarea, Lavendula officinalis and Myrtus communis have repellency effect, even with 10% concentration of essential oils.

  5. Typical Monoterpenes as Insecticides and Repellents against Stored Grain Pests

    Directory of Open Access Journals (Sweden)

    Suelen L. Reis

    2016-02-01

    Full Text Available Five monoterpenes naturally occurring in essential oils were tested for their insecticidal and repellent activities against the bruchid beetle Callosobruchus maculatus and the maize weevil Sitophilus zeamais. The monoterpenes were highly efficient as inducers of mortality or repellency against both insect species. They were more efficient in their fumigant activity against C. maculatus than against S. zeamais, while this profile of action was inverted when considering the repellent activities. Eugenol was one the most effective fumigants against both insects and one the most effective repellent against C. maculatus, while citronellal and geranial were one the most effective repellents against S. zeamais. Functional and positional isomerism of the monoterpenes pairs appears to exert little or no influence on theirs effects, especially in case of repellency. The validation of the insecticidal/repellent efficacy of isolated monoterpenes may permit a more advantageous, rapid, economic and optimized approach to the identification of promising oils for commercial formulations when combined with ethnobotanical strategies.

  6. Bug repellent safety

    Science.gov (United States)

    ... insect is gone. Alternative Names Insect repellent safety Images Bee sting References Fradin MS. Insect repellents. In: Wolverton SE, ed. Comprehensive Dermatologic Drug Therapy . 3rd ed. Philadelphia, PA: Elsevier Saunders; ...

  7. Field evaluation of spatial repellency of metofluthrin-impregnated latticework plastic strips against Aedes aegypti (L.) and analysis of environmental factors affecting its efficacy in My Tho City, Tien Giang, Vietnam.

    Science.gov (United States)

    Kawada, Hitoshi; Iwasaki, Tomonori; LE Loan, Luu; Tien, Tran Khanh; Mai, Nguyen Thi Nhu; Shono, Yoshinori; Katayama, Yasuyuki; Takagi, Masahiro

    2006-12-01

    Spatial repellency of metofluthrin-impregnated polyethylene latticework plastic strips against Aedes aegypti mosquitoes was evaluated. Analysis of environmental factors affecting the efficacy of these strips, such as room temperature, humidity, and house structure, was performed in a residential area in My Tho City, Tien Giang Province, Vietnam. Treatment with the strips at the rate of 1 strip per 2.6-5.52 m(2) (approximately 600 mg per 2.6-5.52 m(2)) reduced the collection of Ae. aegypti resting inside the houses for at least eight weeks. Multiple regression analysis indicated that both increase in the average room temperature and decrease in the area of openings in the rooms that were treated with the strips positively affected the spatial repellency of metofluthrin.

  8. Repellent efficacy of DEET, MyggA, neem (Azedirachta indica) oil and chinaberry (Melia azedarach) oil against Anopheles arabiensis, the principal malaria vector in Ethiopia.

    Science.gov (United States)

    Abiy, Ephrem; Gebre-Michael, Teshome; Balkew, Meshesha; Medhin, Girmay

    2015-05-03

    In Ethiopia, Anopheles arabiensis is the main vector responsible for the transmission of malaria in the country and its control mainly involves application of indoor residual spraying (IRS) and use of insecticide-treated bed nets (ITNs). Although the role of repellents for reducing man-vector contact is documented in the literature, the response of An. arabiensis to repellents was not previously evaluated under field conditions in Ethiopia. The trial was conducted in Sodere village assessing the repellent activities of four repellents, of which, two of them were commercially available DEET (N, N-diethyl-1,3-methylbenzamide) and MyggA (p-methane diol) and the other two were laboratory- produced, 20% neem oil and 20% chinaberry oil. A 6 by 6 Latin square design was employed by involving six volunteers who received rotated treatments of repellents and the Ethiopian Niger seed, noog abyssinia (Guizotia abyssinia), and locally called as noog oil (diluents to the two plant oils). Each volunteer also served as control. Volunteers were positioned at a distance of 20-40 m from each other and each was treated with one of the repellents, Niger seed/noog/ oil or untreated. Landing mosquitoes were collected from dusk to down using tests tubes. The tests were done in three replicates. Both DEET and MyggA provided more than 96% protection. The mean protection time for DEET was 8 hrs while the time for MyggA was 6 hrs. Protection obtained from neem oil and chinaberry oil was almost similar (more than 70%), however, the complete protection time for neem was 3 hrs, while that of chinaberry oil was one hour. The commercial products and laboratory-produced repellents can be utilized by individuals to avoid contact with An. arabiensis in Ethiopia.

  9. Novel Carboxamides as Potential Mosquito Repellents

    Science.gov (United States)

    2010-09-01

    deet) is themost ef- fective andbest-studied arthropod repellent currently on the market . However, it does not provide a long duration of protection...Gaudin, J. M., T. Lander, and O. Nikolaenko. 2008. Carbox- amides combining favorable olfactory properties with insect repellency. Chem. Biodivers. 5

  10. Studies on interaction of insect repellent compounds with odorant binding receptor proteins by in silico molecular docking approach.

    Science.gov (United States)

    Gopal, J Vinay; Kannabiran, K

    2013-12-01

    The aim of the study was to identify the interactions between insect repellent compounds and target olfactory proteins. Four compounds, camphor (C10H16O), carvacrol (C10H14O), oleic acid (C18H34O2) and firmotox (C22H28O5) were chosen as ligands. Seven olfactory proteins of insects with PDB IDs: 3K1E, 1QWV, 1TUJ, 1OOF, 2ERB, 3R1O and OBP1 were chosen for docking analysis. Patch dock was used and pymol for visualizing the structures. The interactions of these ligands with few odorant binding proteins showed binding energies. The ligand camphor had showed a binding energy of -136 kcal/mol with OBP1 protein. The ligand carvacrol interacted with 1QWV and 1TUJ proteins with a least binding energy of -117.45 kcal/mol and -21.78 kcal/mol respectively. The ligand oleic acid interacted with 1OOF, 2ERB, 3R1O and OBP1 with least binding energies. Ligand firmotox interacted with OBP1 and showed least binding energies. Three ligands (camphor, oleic acid and firmotox) had one, two, three interactions with a single protein OBP1 of Nilaparvatha lugens (Rice pest). From this in silico study we identified the interaction patterns for insect repellent compounds with the target insect odarant proteins. The results of our study revealed that the chosen ligands showed hydrogen bond interactions with the target olfactory receptor proteins.

  11. Evaluation of catmint oil and hydrogenated catmint oil as repellents for the flour beetles, Tribolium castaneum and Tribolium confusum.

    Science.gov (United States)

    Arthur, Frank H; Fontenot, Emily A; Campbell, James F

    2011-01-01

    Catmint oil and hydrogenated catmint oil were evaluated as repellents for adult Tribolium casteneum (Herbst) (Coleoptera: Tenebrionidae), the red flour beetle, and T. confusum (DuVal), the confused flour beetle, using both a traditional method of visual assessment of distribution and a video recording method to determine movement patterns of individual insects. Visual assessments of distribution using groups of adults showed that the hydrogenated catmint oil was more effective than the pure catmint oil, but there was no significant difference between species. However, when repellency was measured using single insects and the visual recording system, both oils were significantly more repellent to T. castaneum than T. confusum at the concentrations evaluated in the study. Avoidance movement and change in direction when T. castaneum encountered the repellent were observed. Results indicate that repellents may be more accurately assessed using single insects rather than groups of individuals, and simple visual observations of distribution may be less sensitive in measuring repellent efficacy. Procedures for utilizing a video system are described as models for future evaluations of repellents for stored-product beetles.

  12. Buffer zone water repellency: effects of the management practice

    OpenAIRE

    Rasa, Kimmo; Räty, Mari; Nikolenko, Olga; Horn, Rainer; Yli-Halla, Markku; Uusi-Kämppä, Jaana; Pietola, Liisa

    2006-01-01

    Water repellency index R was measured in a heavy clay and a sandy loam, used as arable land or buffer zone (BZ). Further, effect of management practise and ageing of BZs were studied. Water repellency was proved to be a common phenomenon on these soils. Harvesting and grazing increased water repellency as does ageing.Low water repellency is supposed to prevent preferential flows and provide evenly distributed water infiltration pattern through large soil volume, which favours nutrient retention.

  13. Moisture variability resulting from water repellency in Dutch soils

    OpenAIRE

    Dekker, L.W.

    1998-01-01

    The present study suggests that many soils in the Netherlands, in natural as well as in agricultural areas, may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency can lead to the development of unstable wetting and preferential flow paths. Preferential flow has wide-ranging significance for rapi...

  14. Moisture variability resulting from water repellency in Dutch soils.

    NARCIS (Netherlands)

    Dekker, L.W.

    1998-01-01

    The present study suggests that many soils in the Netherlands, in natural as well as in agricultural areas, may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water in

  15. Moisture variability resulting from water repellency in Dutch soils

    NARCIS (Netherlands)

    Dekker, L.W.

    1998-01-01

    The present study suggests that many soils in the Netherlands, in natural as well as in agricultural areas, may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard

  16. Water repellent soils: a state-of-the-art

    Science.gov (United States)

    Leonard F. DeBano

    1981-01-01

    Water repellency in soils was first described by Schreiner and Shorey (1910), who found that some soils in California could not be wetted and thereby were not suitable for agriculture. Waxy organic substances were responsible for the water repellency. Other studies in the early 1900's on the fairy ring phenomenon suggested that water repellency could be caused by...

  17. Water-Repellent Properties of Superhydrophobic and Lubricant-Infused "Slippery" Surfaces: A Brief Study on the Functions and Applications.

    Science.gov (United States)

    Cao, Moyuan; Guo, Dawei; Yu, Cunming; Li, Kan; Liu, Mingjie; Jiang, Lei

    2016-02-17

    Bioinspired water-repellent materials offer a wealth of opportunities to solve scientific and technological issues. Lotus-leaf and pitcher plants represent two types of antiwetting surfaces, i.e., superhydrophobic and lubricant-infused "slippery" surfaces. Here we investigate the functions and applications of those two types of interfacial materials. The superhydrophobic surface was fabricated on the basis of a hydrophobic fumed silica nanoparticle/poly(dimethylsiloxane) composite layer, and the lubricant-infused "slippery" surface was prepared on the basis of silicone oil infusion. The fabrication, characteristics, and functions of both substrates were studied, including the wettability, transparency, adhesive force, dynamic droplet impact, antifogging, self-cleaning ability, etc. The advantages and disadvantages of the surfaces were briefly discussed, indicating the most suitable applications of the antiwetting materials. This contribution is aimed at providing meaningful information on how to select water-repellent substrates to solve the scientific and practical issues, which can also stimulate new thinking for the development of antiwetting interfacial materials.

  18. Optimization of pyrethroid and repellent on fabrics against Stegomyia albopicta (=Aedes albopictus) using a microencapsulation technique.

    Science.gov (United States)

    Yao, T-T; Wang, L-K; Cheng, J-L; Hu, Y-Z; Zhao, J-H; Zhu, G-N

    2015-03-01

    A new approach employing a combination of pyrethroid and repellent is proposed to improve the protective efficacy of conventional pyrethroid-treated fabrics against mosquito vectors. In this context, the insecticidal and repellent efficacies of commonly used pyrethroids and repellents were evaluated by cone tests and arm-in-cage tests against Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae). At concentrations of LD50 (estimated for pyrethroid) or ED50 (estimated for repellent), respectively, the knock-down effects of the pyrethroids or repellents were further compared. The results obtained indicated that deltamethrin and DEET were relatively more effective and thus these were selected for further study. Synergistic interaction was observed between deltamethrin and DEET at the ratios of 5 : 1, 2 : 1, 1 : 1 and 1 : 2 (but not 1 : 5). An optimal mixing ratio of 7 : 5 was then microencapsulated and adhered to fabrics using a fixing agent. Fabrics impregnated by microencapsulated mixtures gained extended washing durability compared with those treated with a conventional dipping method. Results indicated that this approach represents a promising method for the future impregnation of bednet, curtain and combat uniform materials.

  19. Evaluation of percutaneous absorption of the repellent diethyltoluamide and the sunscreen ethylhexyl p-methoxycinnamate-loaded solid lipid nanoparticles: an in-vitro study.

    Science.gov (United States)

    Puglia, Carmelo; Bonina, Francesco; Castelli, Francesco; Micieli, Dorotea; Sarpietro, Maria Grazia

    2009-08-01

    Diethyltoluamide and ethylhexyl p-methoxycinnamate (OMC) are two active ingredients in insect repellent and sunscreen products, respectively. The concurrent application of these two substances often increases their systemic absorption, compromising the safety and efficiency of the cosmetic product. In this study, diethyltoluamide and OMC were incorporated into solid lipid nanoparticles, a colloidal drug delivery system, to reduce percutaneous absorption and avoid toxic effects and also maintain the efficacy of the two active compounds on the skin surface for a long duration. Solid lipid nanoparticles were prepared based on an ultrasonication technique and characterized by differential scanning calorimetry (DSC) analyses. In-vitro studies determined the percutaneous absorption of diethyltoluamide and OMC. DSC data carried out on unloaded and diethyltoluamide- and/or OMC-loaded solid lipid nanoparticles highlighted that diethyltoluamide and OMC modified the temperature and the enthalpy change associated to the calorimetric peak of solid lipid nanoparticles. The concurrent presence of the two compounds in the solid lipid nanoparticles caused a synergic effect, indicating that the lipid matrix of nanoparticles guaranteed a high encapsulation of both diethyltoluamide and OMC. Results from the in-vitro study demonstrated that the particles were able to reduce the skin permeation of the two cosmetic ingredients in comparison with an oil-in-water emulsion. This study has provided supplementary evidence as to the potential of lipid nanoparticles as carriers for topical administration of cosmetic active compounds.

  20. Comparison of Repellency Effect of Mosquito Repellents for DEET, Citronella, and Fennel Oil

    Science.gov (United States)

    Yoon, Jong Kwang; Kim, Kang-Chang; Cho, Yeondong; Gwon, Yong-Dae; Cho, Han Sam; Heo, Yoonki; Park, Kihoon; Lee, Yang-Won; Kim, Mijeong; Oh, Yu-Kyoung; Kim, Young Bong

    2015-01-01

    To confirm that Korean Food and Drug Administration (KFDA) guidelines are applicable to test the efficacy of mosquito repellents, these guidelines were used to test the efficacy and complete protection times (CPTs) of three representative mosquito repellents: N,N-diethyl-3-methylbenzamide (DEET), citronella, and fennel oil. The repellency of citronella oil decreased over time, from 97.9% at 0 h to 71.4% at 1 h and 57.7% at 2 h, as did the repellency of fennel oil, from 88.6% at 0 h to 61.2% at 1 h and 47.4% at 2 h. In contrast, the repellency of DEET remained over 90% for 6 h. The CPT of DEET (360 min) was much longer than the CPTs of citronella (10.5 min) and fennel oil (8.4 min). These results did not differ significantly from previous findings, and hence confirm that the KFDA guidelines are applicable for testing the efficacy of mosquito repellents. PMID:26527362

  1. Are insect repellents toxic to freshwater insects? A case study using caddisflies exposed to DEET.

    Science.gov (United States)

    Campos, Diana; Gravato, Carlos; Quintaneiro, Carla; Koba, Olga; Randak, Tomas; Soares, Amadeu M V M; Pestana, João L T

    2016-04-01

    Stream ecosystems face ever-increasing pressures by the presence of emergent contaminants, such as, personal care products. N, N-diethyl-3-methylbenzamide (DEET) is a synthetic insect repellent that is being found in surface waters environments in concentrations up to 33.4 μg/L. Information concerning DEET's toxicity in the aquatic environment is still limited and focused only on its acute effects on model species. Our main objective was to assess the effects of DEET exposure to a caddisfly non-target species using sub-lethal endpoints. For that, we chose Sericostoma vittatum, an important shredder in Portuguese freshwaters that has been already used in different ecotoxicological assays. Besides acute tests, S. vittatum were exposed during 6 days to a gradient of DEET concentrations (8, 18 and 40.5 mg/L) to assess effects on feeding behaviour and biochemical responses, such as, lipid peroxidation levels (LPO), catalase and acetylcholinesterase (AChE) activities, and also assess effects on energy reserves and consumption. Acute tests revealed a 48 h-LC50 of 80.12 mg/L and DEET exposure caused feeding inhibition with a LOEC of 36.80 mg/L. Concerning the biochemical responses, DEET caused no effects in LPO nor on catalase activity. A non-significant decrease in AChE activity was observed. Regarding energetic reserves, exposure to DEET caused a significant reduction in S. vittatum carbohydrates levels. These results add important information for the risk assessment of insect repellents in the aquatic environment and suggest that reported environmental concentrations of DEET are not toxic to non-target freshwater insects.

  2. Limitation of using synthetic human odours to test mosquito repellents

    Directory of Open Access Journals (Sweden)

    Mbeyela Edgar

    2009-07-01

    Full Text Available Abstract Background Gold-standard tests of mosquito repellents involve exposing human volunteers to host-seeking mosquitoes, to assess the protective efficacy of the repellents. These techniques are not exposure-free and cannot be performed prior to toxicological evaluation. It is postulated that synthetic lures could provide a useful assay that mimics in-vivo conditions for use in high-throughput screening for mosquito repellents. Methods This paper reports on a semi-field evaluation of repellents using a synthetic blend of human derived attractants for the malaria vector, Anopheles gambiae sensu stricto Different concentrations of known repellents, N, N diethyl-3-methylbenzamide (deet and Para-methane-3, 8, diol (PMD were added into traps baited with the synthetic blend, and resulting changes in mosquito catches were measured. Results All test concentrations of deet (0.001% to 100% reduced the attractiveness of the synthetic blend. However, PMD was repellent only at 0.25%. Above this concentration, it significantly increased the attractiveness of the blend. There was no relationship between the repellent concentrations and the change in mosquito catches when either deet (r2 = 0.033, P = 0.302 or PMD (r2 = 0.020, P = 0.578 was used. Conclusion It is concluded that while some repellents may reduce the attractiveness of synthetic human odours, others may instead increase their attractiveness. Such inconsistencies indicate that even though the synthetic attractants may provide exposure-free and consistent test media for repellents, careful selection and multiple-repellent tests are necessary to ascertain their suitability for use in repellent screening. The synthetic odour blend tested here is not yet sufficiently refined to serve as replacement for humans in repellent testing, but may be developed further and evaluated in different formats for exposure free repellent testing purposes.

  3. Insect Repellent Properties of Melaleuca alternifolia

    Directory of Open Access Journals (Sweden)

    Mohamad Adib Bin Edris

    2016-08-01

    Full Text Available The aim of this study is to compare the use of plant-based insect repellents that are environment friendly with the use of insect repellents based on chemical substances which can be harmful to the environment and human health. The plant studied here is "tea tree"; its scientific name is Melaleuca alternifolia. Essential oil from this plant is extracted by steam distillation method. Based on the previous research, tea tree oil has antimicrobial, antifungal, anti-inflammatory, and insect repellent properties. Some experiments were done on tea tree oil to determine its insect repellent properties and the suitable concentration that can be used to make sure its repelling effect is optimum. The purpose of this determination is to avoid its harmful effect on humans because it can be toxic if it is used at high concentration. The results showed that tea tree oil repelled Tribolium castaneum. Furthermore, the toxicity assays also gave positive result where the tea tree oil has toxic properties against Solenopsis invicta. The lethal dose (LD of tea tree oil to kill 50% of a group of S. invicta is 23.52 µL/mL. This LD50 is determined by using the arithmetic method of Karber. Broadly, the results showed that M. alternifolia has insect repellent properties and shows toxicity against certain insects.

  4. Protection capacity of mosquito repellent ink from citronella (Cymbopogon nardus L.) and clove leaf oils (Syzygium aromaticum) againts Aedes aegypti

    Science.gov (United States)

    Harismah, Kun; Vitasari, Denny; Mirzaei, Mahmoud; Fuadi, Ahmad Muhammad; Aryanto, Yanur Hendra

    2017-06-01

    The study of combination citronella and clove oils in mosquito repellent newspaper ink has been done. The background of this study was there prevalences of diseases such as malaria, zikka, and dengue fever that are carried by mosquitoes which hunt in the morning, at time while people usually read newspaper. Tests were undertaken in 3 (three) repetitions to determine the effectiveness of ink (as a control) and two types of mosquito repellent inks that consisted of ink and citronella-clove leaf oil with ratio of 4:1 and 1:1 of substances that were presumed to have insect repellent qualities. The results of this study indicated that the mixture of newspaper ink and citronella-clove oil with ratio of 1:4 and 1:1 offer limited protection against mosquitoes bite in the range of 1-5 hours. The efficacy of the citronella-clove leaf oi mixture as mosquito repellent was between 75.85 to 91.10%. Hece, a blend of citronella and clove leaf oil could be added to printing ink and could be commercial potential as a short-period mosquito repellent. However, it is important in disseminating public health messages to emphasize the greater effectiveness of citronella and clove oils-based repellents ink in areas with risks of mosquito-borne disease.

  5. Synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils.

    Science.gov (United States)

    Das, N G; Dhiman, Sunil; Talukdar, P K; Rabha, Bipul; Goswami, Diganta; Veer, Vijay

    2015-01-01

    Mosquito repellents play an important role in preventing man-mosquito contact. In the present study, we evaluated the synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils. The mosquito repellent efficacies of three essential oils were evaluated separately and in combination under laboratory and field conditions. N,N-Diethylphenylacetamide (DEPA) and dimethylphthalate (DMP) were used for comparison of the protection time of the mixture of essential oils. At an optimum concentration of 20%, the essential oils of C. longa, Z. limonella and P. heyneanus provided complete protection times (CPTs) of 96.2, 91.4 and 123.4 min, respectively, against Aedes albopictus mosquitoes in the laboratory. The 1:1:2 mixture of the essential oils provided 329.4 and 391.0 min of CPT in the laboratory and field trials, respectively. The percent increases in CPTs for the essential oil mixture were 30 for DMP and 55 for N,N-diethylphenylacetamide (DEPA). The synergistic repellent activity of the essential oils used in the present study might be useful for developing safer alternatives to synthetic repellents for personal protection against mosquitoes.

  6. Comparison of the effect of two excipients (karite nut butter and vaseline on the efficacy of Cocos nucifera, Elaeis guineensis and Carapa procera oil-based repellents formulations against mosquitoes biting in Ivory Coast

    Directory of Open Access Journals (Sweden)

    Konan Y.L.

    2003-06-01

    Full Text Available Repellents in the form of dermal pomades are recommended as a protection against awakening and bedtime mosquito bites. If synthesis repellents are available, they are nevertheless not common and the prices remain out of reach for the communities concerned. The people therefore have to resort more and more to traditional concoctions, some of which have been shown to be effective. After demonstrating that oil-based formulations (lotions, creams, pomades of Cocos nucifera (coconut, Elaeis guineensis (oil palm and Carapa procera (gobi were effective against mosquitoes, it became necessary to study the impact of the two excipients used in their manufacture, on the effectiveness of the repellents. Experiments were carried with Anopheles gambiae and Aedes aegypti under lobaratory conditions and any other mosquitoes collected under field conditions in Ivory Coast. The laboratory results indicate that the average protection times obtained with formulations with karite nut butter as excipient (54.8 ± 37.0 mn and 74.6 ± 26.4 mn respectively on An. gambiae and Ae. aegypti are higher than those recorded with vaseline as excipient (respectively 42.7 ± 30.0 mn and 60.8 ± 33.9 mn. On the other hand, under field conditions, the biting rate percentage reduction obtained with the products with karite nut butter and vaseline excipient were similar (respectively 29.8 % and 35.9 % for all mosquitoes collected and 45.7 % and 47.4 % against An. gambiae. Nevertheless, the use of karite nut butter on repellent products should be encouraged because its sale price is very lower (10 time less than the vaseline's.

  7. Reducing Insects Contaminations through Stored Foodstuffs by Use of Packaging and Repellency Essential Oils

    Directory of Open Access Journals (Sweden)

    Somaye ALLAHVAISI

    2010-12-01

    Full Text Available Protection of stored agricultural products against insects is carried out with chemical insecticides. They have harmful effects for human being, animal and environment. This research carried out on plant essential oils, which are one of the harmless materials and act like contact-fumigant from offering the prospect for using in stored product. They should have the ability to repel the insects. The objective of the present study was to test the properties of Prunus amygdalus L. and Mentha viridis L. for preventing the penetration of pest insects, including: T. castaneum, S. granaries, S. paniceum and R. dominica, to packaged cereals. As foodstuff was packaged by PE polymer and placed into a container 10 g of wheat and flour. The repellent essential oils used in the interior surface of containers. The releasing of insects carried out around the containers to determinate the insect�s penetration percentage with effect of repellents. The highest concentration counted was 1.75 ?l of essential oil per 0.5 ml acetone. The results showed that P. amygdalus had the most repellency effect on T. castaneum that cause 78.52% contamination deduction inside the packaged crop in comparing with control. In addition, M. viridis caused the most repellency on S. granarius (63.81%. The results demonstrated the efficacy of these essential oils for using it in organic food protection. They can prevent the infestation of the stored-product pests to the warehouse.

  8. An Evidence-Based Review on Medicinal Plants Used as Insecticide and Insect Repellent in Traditional Iranian Medicine

    Science.gov (United States)

    Cheraghi Niroumand, Mina; Farzaei, Mohammad Hosein; Karimpour Razkenari, Elahe; Amin, Gholamreza; Khanavi, Mahnaz; Akbarzadeh, Tahmineh; Shams-Ardekani, Mohammad Reza

    2016-01-01

    Context Insects can be the cause of major ecological problems; they can transmit microbes and parasites that affect humans, and damage food crops, trees, and homes. The total economic cost of insect-related damage and disease is immeasurable. In traditional Iranian medicine (TIM), several medicinal plants have been identified as insecticides or insect repellents, but many of them are still unknown. Therefore, the aim of this study was to review the insecticidal or insect repellent activity of certain medicinal plants described in TIM. Evidence Acquisition Information about medicinal plants proposed as insecticides and insect repellents in the TIM was collected from the TIM literature, and searched in modern medical databases to find studies that confirmed their efficacy. Results Modern investigations have supported the claims of the insecticidal activity of several plants, including Allium sativum, Artemisia absinthium, Citrullus colocynthis, Laurus nobilis, Mentha pulegium, Myrtus communis, Nerium oleander, Ocimum basilicum, and Origanum majorana. However, in the cases of plants like Iris florentina and Malva sylvestris, there is not enough evidence in modern medicine to prove their effectiveness with regard to their insecticidal and insect repellent activities. Conclusions This study confirmed the Iranian traditional medicine claims of the insecticidal and insect repellent activity of certain plants. Further pharmacological and clinical studies are recommended to evaluate the overall efficacy and possible mechanisms underlying these herbs. PMID:27186389

  9. An Evidence-Based Review on Medicinal Plants Used as Insecticide and Insect Repellent in Traditional Iranian Medicine.

    Science.gov (United States)

    Cheraghi Niroumand, Mina; Farzaei, Mohammad Hosein; Karimpour Razkenari, Elahe; Amin, Gholamreza; Khanavi, Mahnaz; Akbarzadeh, Tahmineh; Shams-Ardekani, Mohammad Reza

    2016-02-01

    Insects can be the cause of major ecological problems; they can transmit microbes and parasites that affect humans, and damage food crops, trees, and homes. The total economic cost of insect-related damage and disease is immeasurable. In traditional Iranian medicine (TIM), several medicinal plants have been identified as insecticides or insect repellents, but many of them are still unknown. Therefore, the aim of this study was to review the insecticidal or insect repellent activity of certain medicinal plants described in TIM. Information about medicinal plants proposed as insecticides and insect repellents in the TIM was collected from the TIM literature, and searched in modern medical databases to find studies that confirmed their efficacy. Modern investigations have supported the claims of the insecticidal activity of several plants, including Allium sativum, Artemisia absinthium, Citrullus colocynthis, Laurus nobilis, Mentha pulegium, Myrtus communis, Nerium oleander, Ocimum basilicum, and Origanum majorana. However, in the cases of plants like Iris florentina and Malva sylvestris, there is not enough evidence in modern medicine to prove their effectiveness with regard to their insecticidal and insect repellent activities. This study confirmed the Iranian traditional medicine claims of the insecticidal and insect repellent activity of certain plants. Further pharmacological and clinical studies are recommended to evaluate the overall efficacy and possible mechanisms underlying these herbs.

  10. Advance of Study on Soil Water Repellency%土壤斥水性研究进展

    Institute of Scientific and Technical Information of China (English)

    李毅; 商艳玲; 李振华; 刘世宾

    2012-01-01

    简述了土壤斥水的基本概念,归纳了土壤斥水对农田水分循环、水土保持、地下水环境等的影响,分析了土壤斥水发生的原因,总结了国内外已采用的斥水度测定方法及其各自特点,并对土壤斥水度空间变异性、斥水土壤在入渗和蒸发过程中的水分运动规律及斥水土壤入渗性能改善方法的研究现状作了较全面的分析和评述.由于土壤斥水与农田水分循环、微生物活动、产流产沙和地下水环境污染之间存在密切联系,因此有必要进行相关问题的研究.%The basic concept of soil water repellency was introduced, the effects of soil water repellency on field water cycle, soil and water conservation, and ground water environment was summed up. The reasons of soil water repellency were analyzed. The domestic and international methods used for detecting the degree of soil water repellency and their characteristics were introduced. The research advancement of spatial variability for soil water repellency, soil water movement of water repellent soil during infiltration and evaporation process, and measures for improving infiltration ability of hydrophobic soil were also reviewed and assessed thoroughly. Since there were closed associations between soil water repellency and filed water cycle, microbe activity, runoff and sediment production, and pollution of ground water environment, it was urgent to do related research.

  11. Rural buyers' perception about mosquito repellants

    Directory of Open Access Journals (Sweden)

    D. MEHTA

    2010-06-01

    Full Text Available Mosquito repellants prevent mosquito bites and prevention of "man-mosquito contact" is a critical factor in transmission and spread of any disease through mosquitoes particularly in rural area. There has been a long standing 'bias' towards rural buyers. The rural markets are considered rigid in the nature but it is not the case in real sense. Marketing to rural buyers is not only a challenge to the marketers but to the manufacturers, communicators, national planners and economists as well. That is why it has been necessary to understand the various aspects of selected rural areas and consumption pattern for such a fast growing market i.e. mosquito repellants and rural buyers’ perception towards such urban products. The present paper aims to find out the factors influencing the purchase decisions of rural buyers for mosquito repellants and to study the perceptions of present and potential rural buyers' of selected mosquito repellant brands.

  12. Repellency Awareness Graphic

    Science.gov (United States)

    Companies can apply to use the voluntary new graphic on product labels of skin-applied insect repellents. This graphic is intended to help consumers easily identify the protection time for mosquitoes and ticks and select appropriately.

  13. (Virtual) Water-repellent Law? Why Legal Studies Should Be Brought Into the Virtual Water Debate

    Science.gov (United States)

    Turrini, Paolo

    2014-05-01

    Virtual water studies are a marvelous example of the much praised "interdisciplinary approach", efficaciously intertwining many threads woven by scholars of very diverse fields of research. After all, if water is an object of biological interest and the word "virtual" becomes especially significant in the framework of the international trade flows, why should agronomists and economists not work together? And, with them, hydrologists, environmental engineers, network analysis experts… either working side by side or, at least, following one another's steps. Browsing the relevant academic literature one may notice that a vast array of disciplines is dealing with the topic. As a consequence, it may come as a surprise that lawyers seem to have remained almost deaf to the charming call of virtual water. A social science thoroughly "social" even if sometimes deemed (also by its practitioners) akin to humanities - and for this reason not always timely in catching the hints by hard sciences - law has a lot to say about virtual water and its manifold aspects. And it is so, in my opinion, in at least two respects. First of all, legal provisions can be determinants of social facts no less than other types of norms, such as physical or economic laws. Law shapes the human behavior by giving incentives or establishing constraints to the conduct of virtually any kind of social actor, be they farmers needing to decide what to grow, entrepreneurs willing to invest in the water market, or governments requested to address their communities' problems. All of them will make their choices in consideration of the costs, opportunities, and limits set by a number of regulations. In the second place, and strictly connected with the first reason, law may offer some answers to the challenges that virtual water and, more in general, the water-food nexus bring with them. In fact, understanding the way legal provisions affect the taking of decisions in the water sector, one may try to devise

  14. Soil water repellency changes with depth and relationship to physical properties within wettable and repellent soil profiles

    Directory of Open Access Journals (Sweden)

    Sepehrnia Nasrollah

    2017-03-01

    Full Text Available This study explored the effect of soil water repellency (SWR on soil hydrophysical properties with depth. Soils were sampled from two distinctly wettable and water repellent soil profiles at depth increments from 0-60 cm. The soils were selected because they appeared to either wet readily (wettable or remain dry (water repellent under field conditions. Basic soil properties (MWD, SOM, θv were compared to hydrophysical properties (Ks, Sw, Se, Sww, Swh, WDPT, RIc, RIm and WRCT that characterise or are affected by water repellency. Our results showed both soil and depth affected basic and hydrophysical properties of the soils (p <0.001. Soil organic matter (SOM was the major property responsible for water repellency at the selected depths (0-60. Water repellency changes affected moisture distribution and resulted in the upper layer (0-40 cm of the repellent soil to be considerably drier compared to the wettable soil. The water repellent soil also had greater MWDdry and Ks over the entire 0-60 cm depth compared to the wettable soil. Various measures of sorptivity, Sw, Se, Sww, Swh, were greater through the wettable than water repellent soil profile, which was also reflected in field and dry WDPT measurements. However, the wettable soil had subcritical water repellency, so the range of data was used to compare indices of water repellency. WRCT and RIm had less variation compared to WDPT and RIc. Estimating water repellency using WRCT and RIm indicated that these indices can detect the degree of SWR and are able to better classify SWR degree of the subcritical-repellent soil from the wettable soil.

  15. Mini Review: Mode of Action of Mosquito Repellents

    Science.gov (United States)

    2013-01-01

    Mini review: Mode of action of mosquito repellents Joseph C. Dickens ⇑, Jonathan D. Bohbot United States Department of Agriculture, Agricultural...Modulation a b s t r a c t The mode of action of mosquito repellents remains a controversial topic. However, electrophysiological studies and molecular...annoyance that can disrupt outdoor activities. The use of repellents decreases contacts between mosquitoes and their hosts, and may even lower the rate of

  16. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    OpenAIRE

    Youngmin Choi; Hyunwook Choo; Tae Sup Yun; Changho Lee; Woojin Lee

    2016-01-01

    Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10%...

  17. Repellent activities of dichloromethane extract of Allium sativum (garlic (Liliaceae against Hyalomma rufipes (Acari

    Directory of Open Access Journals (Sweden)

    Felix Nchu

    2016-02-01

    Full Text Available Dichloromethane (DCM extract of garlic (Allium sativum Linn. bulbs was assessed for its repellent effect against the hard tick, Hyalomma rufipes (Acari: Ixodidae using two tick behavioural bioassays; Type A and Type B repellency bioassays, under laboratory conditions. These bioassays exploit the questing behaviour of H. rufipes, a tick that in nature displays ambush strategy, seeking its host by climbing up on vegetation and attaching to a passing host. One hundred microlitres (100 µL of the test solution containing DCM extract of garlic bulbs and DCM at concentrations of 0.35%, 0.7% or 1.4% w/v were evaluated. DCM only was used for control. Tick repellency increased significantly (R2 = 0.98 with increasing concentration (40.03% – 86.96% yielding an EC50 of 0.45% w/v in Type B repellency bioassay. At concentration of 1.4% w/v, the DCM extract of garlic bulbs produced high repellency index of 87% (male ticks and 87.5% (female ticks in the Type A repellency bioassay. Only 4% avoidance of male ticks or female ticks was recorded in the Type B repellency bioassay. In the corresponding controls, the mean numbers of non-repelled male or female ticks were 80% and 41 males or 38 females of 50 ticks in the Type A and Type B repellency bioassays, respectively. The variations in the results could be attributed to the difference in tick repellent behaviours that were assessed by the two repellency bioassays; the Type A repellency bioassay assessed repellent effect of garlic extracts without discriminating between deterrence and avoidance whereas the Type B repellency bioassay only assessed avoidance response. Generally, DCM extract of garlic was repellent against H. rufipes, albeit weak tick repellency was obtained in the Type B repellency bioassay. Furthermore, this study established that the tick repellent activity of garlic extracts is predominantly by deterrence.

  18. Repellent activities of dichloromethane extract of Allium sativum (garlic) (Liliaceae) against Hyalomma rufipes (Acari).

    Science.gov (United States)

    Nchu, Felix; Magano, Solomon R; Eloff, Jacobus N

    2016-12-02

    Dichloromethane (DCM) extract of garlic (Allium sativum Linn.) bulbs was assessed for its repellent effect against the hard tick, Hyalomma rufipes (Acari: Ixodidae) using two tick behavioural bioassays; Type A and Type B repellency bioassays, under laboratory conditions. These bioassays exploit the questing behaviour of H. rufipes, a tick that in nature displays ambush strategy, seeking its host by climbing up on vegetation and attaching to a passing host. One hundred microlitres (100 µL) of the test solution containing DCM extract of garlic bulbs and DCM at concentrations of 0.35%, 0.7% or 1.4% w/v were evaluated. DCM only was used for control. Tick repellency increased significantly (R2 = 0.98) with increasing concentration (40.03% - 86.96%) yielding an EC50 of 0.45% w/v in Type B repellency bioassay. At concentration of 1.4% w/v, the DCM extract of garlic bulbs produced high repellency index of 87% (male ticks) and 87.5% (female ticks) in the Type A repellency bioassay. Only 4% avoidance of male ticks or female ticks was recorded in the Type B repellency bioassay. In the corresponding controls, the mean numbers of non-repelled male or female ticks were 80% and 41 males or 38 females of 50 ticks in the Type A and Type B repellency bioassays, respectively. The variations in the results could be attributed to the difference in tick repellent behaviours that were assessed by the two repellency bioassays; the Type A repellency bioassay assessed repellent effect of garlic extracts without discriminating between deterrence and avoidance whereas the Type B repellency bioassay only assessed avoidance response. Generally, DCM extract of garlic was repellent against H. rufipes, albeit weak tick repellency was obtained in the Type B repellency bioassay. Furthermore, this study established that the tick repellent activity of garlic extracts is predominantly by deterrence.

  19. Study of water repellent finishing on cotton with fluorosilicon soap-free water repellent agent%氟硅无皂拒水剂在棉织物拒水整理中的应用

    Institute of Scientific and Technical Information of China (English)

    李智斌; 樊增禄; 毛宁涛; 李庆; 蔡信彬

    2016-01-01

    为提高棉织物的拒水性能,采用自制的氟硅无皂拒水剂对棉织物进行整理.通过单因素试验优化拒水整理的工艺条件,测试拒水整理棉织物的拒水性及透气性等,并与市售拒水剂进行对比.结果表明,在氟硅无皂拒水剂60g/L ,二浸二轧,100℃下预烘4min ,170℃下焙烘3min ,整理后棉织物对水的接触角达到138.6°,静水压为2.83kPa ,表现出良好的拒水效果.%In order to improve the properties of water repellency for cotton fabrics ,selfmade flu-orosilicon soap-free water repellent agent is used to finish cotton fabric .The process conditions of water repellent finishing was optimized by single factor test ,the water repellency and air permeability of the finished cotton fabric were tested ,and compared with the market-sold water repellent agents .The result shows that using 60g/L fluorosilicon soap-free water repellent a-gent ,two-padding two-rolling ,drying at 100 ℃ for 4min ,baking at 170 ℃ for 3min ,the con-tact angle and hydrostatic pressure reached 138.6° and 2.83kPa ,the cotton fabric treated ex-hibited good water-repellent properties .

  20. Control of tungiasis through intermittent application of a plant-based repellent: an intervention study in a resource-poor community in Brazil.

    Directory of Open Access Journals (Sweden)

    John Buckendahl

    Full Text Available BACKGROUND: Tungiasis, an ectoparasitosis caused by the female sand flea Tunga penetrans, is an important health problem in many impoverished communities in the tropics. Sand flea disease is associated with a broad spectrum of clinical pathology and severe sequels are frequent. Treatment options are limited. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the effectiveness of the intermittent application of the plant-based repellent Zanzarin to reduce infestation intensity and tungiasis-associated morbidity in a resource-poor community in Brazil, characterized by a very high attack rate. The study population was randomized into three cohorts. Initially, during a period of four weeks, the repellent was applied twice daily to the feet of all cohort members. This reduced the number of embedded sandfleas to 0 in 98% of the participants. Thereafter members of cohort A applied the repellent every second week twice daily for one week, members of cohort B every fourth week for one week, and members of cohort C served as controls. Infestation intensity and tungiasis-associated morbidity were monitored during five months. The intermittent application of Zanzarin for one week every second week significantly reduced infestation intensity from a median 4 lesions (IQR 1-9 during the whole transmission season. In contrast, in cohort B (application of the repellent every fourth week the infestation intensity remained twice as high (median 8 lesions, IQR 9-16; p = 0.0035, and in the control cohort C 3.5 times as high (median 14 lesions; IQR 7-26; p = 0.004 during the transmission season. Tungiasis-related acute pathology remained very low in cohort A (median severity score 2; IQR 1-4 as compared to cohort B (median severity score 5; IQR 3-7; p<0.001, and control cohort C (median severity score 6.5; IQR 4-8; p<0.001. CONCLUSIONS/SIGNIFICANCE: Our study shows that in a setting with intense transmission, tungiasis-associated morbidity can be minimized through

  1. Fumigant and Repellent Activity of Limonene Enantiomers Against Tribolium confusum du Val.

    Science.gov (United States)

    Malacrinò, A; Campolo, O; Laudani, F; Palmeri, V

    2016-10-01

    The use of pesticides, as carried out in the last 50 years, caused several negative environmental and human health consequences, leading to the development of alternative techniques to control pests, such as the use of compounds of plant origin. In this study, we assessed the fumigant and repellent activity of both the enantiomers of limonene, a monoterpene usually found in many plant species, against Tribolium confusum du Val. We tested both molecules at different doses, air temperatures, and in absence and presence of flour. R-(+)-limonene resulted more effective than S-(-)-limonene; indeed, it was able to reach 100% of efficacy at a concentration of 85 mg/L air when tested at different temperatures without flour. Data showed a positive relationship between efficacy and temperature, and a negative effect of the presence of debris on the bioactivity of limonene. Furthermore, repellency trials reported a higher activity of R-(+)-limonene compared to the other enantiomer.

  2. A Fat strange Repeller

    Institute of Scientific and Technical Information of China (English)

    申影; 何阅; 姜玉梅; 何大韧

    2004-01-01

    This article reports an observation on a fat strange repeller, which appears after a characteristic crisis observed in a kicked rotor subjected to a piecewise continuous force field. The discontinuity border in the definition range of the two-dimensional mapping, which describes the system, oscillates as the discrete time develops. At a threshold of a control parameter a fat chaotic attractor suddenly transfers to a fat transient set. The strange repeller, which appears after the crisis, is also a fat fractal. This is the reason why super-transience happens

  3. Laboratory evaluation of traditionally used plant-based insect repellent against the malaria vector Anopheles arabiensis Patton (Diptera: Culicidae).

    Science.gov (United States)

    Karunamoorthi, Kaliyaperumal; Ilango, Kandan; Murugan, Kadarkarai

    2010-04-01

    A laboratory study was carried out to evaluate the repellent efficacy of a methanol-leaf extract of Ethiopian traditionally used insect repellent plant viz., Lomi sar [vernacular name (local native language, Amharic); Cymbopogon citratus (DC) Stapf. (Poaceae)] against Anopheles arabiensis at four different concentrations viz., 1.0, 1.5, 2.0, and 2.5 mg/cm(2). The percentage protection in relation to the dose method was performed. C. citratus extract has shown various degrees of repellency impact against A. arabiensis. It provided the maximum total percentage protection of 78.83% at 2.5 mg/cm(2) and followed 68.06% at 2.0 mg/cm(2) for 12 h. All four tested concentrations of C. citratus extract offered significant protection and Student's t test results shows statistically significant (p value = 0.001) [1.0 mg/cm(2) (t = 22.89; df = 4); 1.5 mg/cm(2) (t = 24.03; df = 4); 2.0 mg/cm(2) (t = 36.92; df = 4); 2.5 mg/cm(2) (t = 22.31; df = 4)] difference between treated and control groups. The result suggests that it could serve as a potent insect repellent against vectors of disease. Globally, C. citratus is renowned for its therapeutic values. Above and beyond, due to its user- as well as environmental-friendly nature, it should be promoted among the marginalized populations in order to reduce man-vector contact. In addition, this appropriate strategy affords the opportunity to minimize chemical repellent usage and the risks associated with adverse side effects. At the end of the day, traditionally used plant-based insect repellents could be viable safer alternative sources for chemical insect repellents.

  4. Insect repellents and associated personal protection for a reduction in human disease

    Science.gov (United States)

    Personal protection measures against biting arthropods include topical insect repellents, area repellents, insecticide-treated bednets and treated clothing. The literature on the effectiveness of personal protection products against arthropods is mainly limited to studies of prevention of bites, rat...

  5. Comparative repellent activities of some plant extracts against Simulium damnosum complex.

    Science.gov (United States)

    Sam-Wobo, Sammy O; Adeleke, Monsuru A; Mafiana, Chiedu F; Surakat, Olabanji H

    2011-08-01

    The root and leaf extracts of four plants, Occimum gratissimum, Azadirachta indica, Pterocarpus santalinoides, and Pistia hyptis, were studied for repellent activities against the adults of Simulium damnosum sensu lato. The leaves and roots were extracted with 95% ethanol and the stocks were diluted with paraffin. The repellent activities of the extracts were investigated using human baits along the banks of River Oyan and River Ogun in southwestern Nigeria. The results showed that the root extract of O. grattissium and leaf extract of P. hyptis had highest repellent potentials with 78% and 78.1% protection against S. damnosum sensu lato, respectively, whereas the root and leaf of P. santalinoides recorded the least. Although there were significant differences in the percentage of protection of the extracts of the plants (p 0.05). The study concludes that there exist some repellent efficacies in the extracts of the plants, most importantly O. grattissimum and P. hyptis. The plant extracts can further be developed in the prevention of man-vector contact in onchocerciasis endemic communities.

  6. Rabbit Repellent Paint

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Five gallons of rabbit repellent paint were sent to George Wilson to be applied on the trees of the Tewaukon tree plot. Mr. Wilson requires a 3 or 4 in. brush for...

  7. Assessment of Angelica sinensis (Oliv.) Diels as a repellent for personal protection against mosquitoes under laboratory and field conditions in northern Thailand.

    Science.gov (United States)

    Champakaew, Danita; Junkum, Anuluck; Chaithong, Udom; Jitpakdi, Atchariya; Riyong, Doungrat; Wannasan, Anchalee; Intirach, Jitrawadee; Muangmoon, Roongtawan; Chansang, Arpaporn; Tuetun, Benjawan; Pitasawat, Benjawan

    2016-06-29

    Angelica sinensis (Oliv.) hexane extract (AHE) has been reported as a proven and impressive repellent against laboratory-reared female Aedes aegypti mosquitoes. With the aim of promoting products of plant origin as a viable alternative to conventional synthetic substances, this study was designed to transform AHE-based repellents for exploitable commercial production by enhancing their efficacy and assessing their physical and biological stability as well as repellency against mosquitoes under laboratory and field conditions. The chemical profile of AHE was analyzed by qualitative gas chromatography-mass spectrometry (GC-MS) technique. AHE was supplemented with vanillin, as a fixative, and then investigated for repellency and comparison to the standard synthetic repellent, DEET, under both laboratory and field conditions. Determination of physical and biological stability as a repellent was carried out after keeping AHE samples under varying temperatures and for different storage times. GC-MS analysis revealed that AHE contained at least 21 phytochemical compounds, constituting 95.74 % of the total content, with the major constituent of 3-N-butylphthalide (66.67 %). Ethanolic formulations of AHE and DEET showed improvement of repellency in a dose-dependent manner when vanillin was added in laboratory assessment. While 5-25 % AHE alone provided median complete-protection times of 2.0-6.5 h against Ae. aegypti, these times were increased to 4.0-8.5 h with a combination of AHE and 5 % vanillin (AHEv). Protection times against Ae. aegypti were extended from 2.25 to 7.25 h to 4.25-8.25 h when 5-25 % DEET was combined with 5 % vanillin (DEETv). In determining stability, all stored AHE samples exhibited similar characteristics such as liquid phases with aromatic odor comparable to those of fresh preparations. Furthermore, repellent activity of stored AHE samples lasted for at least six months, with varied efficacy (4.5-10.0 h) against Ae. aegypti. Field trials

  8. Identification of mosquito repellent odours from Ocimum forskolei.

    Science.gov (United States)

    Dekker, Teun; Ignell, Rickard; Ghebru, Maedot; Glinwood, Robert; Hopkins, Richard

    2011-09-22

    Native mosquito repellent plants have a good potential for integrated mosquito control in local settings. Ocimum forskolei, Lamiaceae, is used in Eritrea as a spatial mosquito repellent inside houses, either through crushing fresh plants or burning dry plants. We verified whether active repellent compounds could be identified using gas-chromatography coupled electroantennogram recordings (GC-EAD) with headspace extracts of crushed plants. EAD active compounds included (R)-(-)-linalool, (S)-(+)-1-octen-3-ol, trans-caryophyllene, naphthalene, methyl salicylate, (R)-(-)-α-copaene, methyl cinnamate and (E)-ocimene. Of these compounds (R)-(-)-linalool, methyl cinnamate and methyl salicylate reduced landing of female Aedes aegypti on human skin-odor baited tubes. The latter two are novel mosquito repellent compounds. The identification of mosquito repellent compounds contributes to deciphering the mechanisms underlying repulsion, supporting the rational design of novel repellents. The three mosquito repellent compounds identified in this study are structurally dissimilar, which may indicate involvement of different sensory neurons in repulsion. Repulsion may well be enhanced through combining different repellent plants (or their synthetic mimics), and can be a locally sustainable part in mosquito control efforts.

  9. Application of actinomycetes to soil to ameliorate water repellency.

    Science.gov (United States)

    McKenna, F; El-Tarabily, K A; Petrie, S; Chen, C; Dell, B

    2002-01-01

    The aim of this study was to develop a novel isolation technique using a mixture of Bacillus and Streptomyces phages to selectively isolate wax-utilizing non-streptomycete actinomycetes effective in ameliorating water repellency in a problem soil. Phages added to a soil suspension reduced the dominance of Bacillus and Streptomyces isolates and significantly increased the number of non-streptomycete actinomycetes on isolation plates. Promising isolates, grown on a medium containing beeswax as sole carbon source, were selected for application to water repellent soil. Their addition significantly reduced water repellency. Phage application significantly increased the isolation of non-streptomycete actinomycetes. Wax-utilizing isolates were found to significantly reduce water repellency in a problem soil. The phage technique can be used for the routine isolation of non-streptomycete actinomycetes. Beeswax medium can be used to selectively isolate wax-utilizing micro-organisms with the potential to ameliorate water repellency in soil.

  10. Repellents Inhibit P450 Enzymes in Stegomyia (Aedes) aegypti

    Science.gov (United States)

    Jaramillo Ramirez, Gloria Isabel; Logan, James G.; Loza-Reyes, Elisa; Stashenko, Elena; Moores, Graham D.

    2012-01-01

    The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s) underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES) arm-in cage assay with Stegomyia (Aedes) aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils. PMID:23152795

  11. Repellents inhibit P450 enzymes in Stegomyia (Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Gloria Isabel Jaramillo Ramirez

    Full Text Available The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES arm-in cage assay with Stegomyia (Aedes aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils.

  12. Water repellent soils: the case for unsaturated soil mechanics

    Directory of Open Access Journals (Sweden)

    Beckett Christopher

    2016-01-01

    Full Text Available Water repellent (or “hydrophobic” or “non-wetting” soils have been studied by soil scientists for well over a century. These soils are typified by poor water infiltration, which leads to increased soil erosion and poor crop growth. However, the importance of water repellence on determining soil properties is now becoming recognised by geotechnical engineers. Water repellent soils may, for example, offer novel solutions for the design of cover systems overlying municipal or mine waste storage facilities. However, investigations into factors affecting their mechanical properties have only recently been initiated. This purpose of this paper is to introduce geotechnical engineers to the concept of water repellent soils and to discuss how their properties can be evaluated under an unsaturated soils framework. Scenarios in which water repellent properties might be relevant in geotechnical applications are presented and methods to quantify these properties in the laboratory and in the field examined.

  13. Repelling Point Bosons

    Science.gov (United States)

    McGuire, J. B.

    2011-12-01

    There is a body of conventional wisdom that holds that a solvable quantum problem, by virtue of its solvability, is pathological and thus irrelevant. It has been difficult to refute this view owing to the paucity of theoretical constructs and experimental results. Recent experiments involving equivalent ions trapped in a spatial conformation of extreme anisotropic confinement (longitudinal extension tens, hundreds or even thousands of times transverse extension) have modified the view of relevancy, and it is now possible to consider systems previously thought pathological, in particular point Bosons that repel in one dimension. It has been difficult for the experimentalists to utilize existing theory, mainly due to long-standing theoretical misunderstanding of the relevance of the permutation group, in particular the non-commutativity of translations (periodicity) and transpositions (permutation). This misunderstanding is most easily rectified in the case of repelling Bosons.

  14. Antennal olfactory sensilla responses to insect chemical repellents in the common bed bug, Cimex lectularius.

    Science.gov (United States)

    Liu, Feng; Haynes, Kenneth F; Appel, Arthur G; Liu, Nannan

    2014-06-01

    Populations of the common bed bug Cimex lectularius (Hemiptera; Cimicidae), a temporary ectoparasite on both humans and animals, have surged in many developed countries. Similar to other haematophagous arthropods, C. lectularius relies on its olfactory system to detect semiochemicals in the environment, including both attractants and repellents. To elucidate the olfactory responses of the common bed bug to commonly used insect chemical repellents, particularly haematophagous repellents, we investigated the neuronal responses of individual olfactory sensilla in C. lectularius' antennae to 52 insect chemical repellents, both synthetic and botanic. Different types of sensilla displayed highly distinctive response profiles. While C sensilla did not respond to any of the insect chemical repellents, Dγ sensilla proved to be the most sensitive in response to terpene-derived insect chemical repellents. Different chemical repellents elicited neuronal responses with differing temporal characteristics, and the responses of the olfactory sensilla to the insect chemical repellents were dose-dependent, with an olfactory response to the terpene-derived chemical repellent, but not to the non-terpene-derived chemical repellents. Overall, this study furnishes a comprehensive map of the olfactory response of bed bugs to commonly used insect chemical repellents, providing useful information for those developing new agents (attractants or repellents) for bed bug control.

  15. Repellent effects of the essential oils of Cymbopogon citratus and Tagetes minuta on the sandfly, Phlebotomus duboscqi.

    Science.gov (United States)

    Kimutai, Albert; Ngeiywa, Moses; Mulaa, Margaret; Njagi, Peter G N; Ingonga, Johnstone; Nyamwamu, Lydia B; Ombati, Cyprian; Ngumbi, Philip

    2017-02-15

    The sandfly, Phlebotomus duboscqi is a vector of zoonotic cutaneous leishmaniasis (ZCL) that is an important public health problem in Eastern Africa. Repellents have been used for protection of humans against vectors of ZCL and other vectors that transmit killer diseases including malaria, Rift Valley fever, dengue, and yellow fever. The repellent effects of different doses of the essential oils from the lemon grass, Cymbopogon citratus and Mexican marigold, Tagetes minuta were evaluated in a two-chamber bioassay against 3- to 7-day-old unfed females of P. duboscqi in the laboratory. The results were compared with those that were obtained when test animals were treated with an equivalent dose of diethyl-3-methylbenzamide, which is a repellent that is commonly used as a positive control. Overall, percentage repellency increased with increasing doses of the essential oils while biting rates decreased with increasing concentrations of the oils. Further, the oil of C. citratus was more potent than that of T. minuta with regard to protection time and biting deterrence. The effective doses at 50% (ED50) and at 90% (ED90) for the oil of C. citratus, were 0.04 and 0.79 mg/ml, respectively. Those of the oil of T. minuta were 0.10 and 12.58 mg/ml. In addition, the percentage repellency of 1 mg/ml of the essential oils of C. citratus and T. minuta against sandflies was 100% and 88.89%, respectively. A lower dose of 0.5 mg/ml of the oils, elicited 89.13% repellency for C. citratus and 52.22% for T. minuta. The laboratory tests showed that the essential oils of the two plants were highly repellent to adult sand flies, P. duboscqi. Thus, the two essential oils are candidate natural repellents that can be used against P. duboscqi due to their high efficacy at very low doses, hence, the envisaged safety in their use over chemical repellents. It remains to carry out clinical studies on human subjects with appropriate formulations of the oils prior to recommending their adoption

  16. Citrus orchards management and soil water repellency in Eastern Spain

    Science.gov (United States)

    Cerdà, A.; González Peñaloza, F. A.; Jordán, A.; Zavala, L. M.

    2012-04-01

    repellency observed in soils under MNT treatment may be attributed to the input of hydrophobic organic compounds as a consequence of the addition of plant residues and organic manure. A further issue to be achieved is the study of geomorphological processes associated to sub-critical soil water repellency. The experimental setup within the citrus plantation is being supported by the research project CGL2008-02879/BTE

  17. FAQ: Insect Repellent Use and Safety

    Science.gov (United States)

    ... Mosquito Surveillance Software Health Education Public Service Videos Insect Repellent Use & Safety Recommend on Facebook Tweet Share ... the repellent with you. Top of Page Can insect repellents be used on children? Yes. Most products ...

  18. Insecticidal and repellent effects of tea tree and andiroba oils on flies associated with livestock.

    Science.gov (United States)

    Klauck, V; Pazinato, R; Stefani, L M; Santos, R C; Vaucher, R A; Baldissera, M D; Raffin, R; Boligon, A; Athayde, M; Baretta, D; Machado, G; DA Silva, A S

    2014-08-01

    This study aimed to evaluate the insecticidal and repellent effects of tea tree, Melaleuca alternifolia (Myrtales: Myrtaceae), and andiroba, Carapa guianensis (Sapindales: Meliaceae), essential oils on two species of fly. For in vitro studies, free-living adult flies were captured and reared in the laboratory. To evaluate the insecticidal effects of the oils, adult flies of Haematobia irritans (L.) and Musca domestica L. (both: Diptera: Muscidae) were separated by species in test cages (n = 10 per group), and subsequently tested with oils at concentrations of 1.0% and 5.0% using a negative control to validate the test. Both oils showed insecticidal activity. Tea tree oil at a concentration of 5.0% was able to kill M. domestica with 100.0% efficacy after 12 h of exposure. However, the effectiveness of andiroba oil at a concentration of 5.0% was only 67.0%. The insecticidal efficacy (100.0%) of both oils against H. irritans was observed at both concentrations for up to 4 h. The repellency effects of the oils at concentrations of 5.0% were tested in vivo on Holstein cows naturally infested by H. irritans. Both oils demonstrated repellency at 24 h, when the numbers of flies on cows treated with tea tree and andiroba oil were 61.6% and 57.7%, respectively, lower than the number of flies on control animals. It is possible to conclude that these essential oils have insecticidal and repellent effects against the species of fly used in this study.

  19. Experimental Study on the Infiltration Laws of Water-Repellent Soils Based on Alcohol Solution%酒精溶液对斥水土壤入渗规律的试验研究

    Institute of Scientific and Technical Information of China (English)

    刘春成; 李毅

    2012-01-01

    Comparative infiltration experimental study based on the 2 soils of different water-repellency degrees was conducted.Indoors soil column experiment were used to carry out the experiment of ponding infiltration to compare the variations of infiltration volumes and infiltration rates versus time of 2 soils in different water-repellency degrees,applicability of Kostiakov equation in water-repellent soils based on the alcohol infiltration was tested,the fitted relations of infiltration versus t-1/2 were explored,as well as distributions of total salt and Cl-contents in the profiles were researched.Results showed that the existence of soil water-repellency has some obvious impacts on the soil infiltration property,but variations of the infiltration capacity among water-repellent soils of different water-repellent degrees,and the infiltration capacity in water-repellent soils was lower than one in wettable soils;the rinsed results of total salt and Cl-were more obvious in water-repellent soils that those in wettable soils,and the maximum was reached at the wetting front;applicability of Kostiakov equation was well about the variations of the infiltration rates versus time;there was good exponential relationship between infiltration rates and t-1/2.The study showed that the existence of soil water-repellency affected alcohol solution infiltration,but water-repellent soil infiltrations of different water-repellent degrees were not influenced by alcohol solution.The process of infiltration based on alcohol solution was accelerated greatly compared to distilled water infiltration.%采用室内土柱积液入渗试验,进行了不同斥水程度的2种土质的酒精溶液和蒸馏水的对比入渗试验研究,对比了不同斥水程度的土壤累积入渗量和入渗率随时间的变化,验证了Kostiakov公式在斥水土壤酒精溶液入渗的适应性,探索了i与t-1/2的拟合关系,以及全盐量和氯离子的剖面分布。结果表明,酒精入渗条件下,

  20. Nectar Theft and Floral Ant-Repellence: A Link between Nectar Volume and Ant-Repellent Traits?

    Science.gov (United States)

    Ballantyne, Gavin; Willmer, Pat

    2012-01-01

    As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were ant-repellent at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that ant-repellent floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost of nectar production in future studies into ant-flower interactions. PMID:22952793

  1. Percutaneous characterization of the insect repellent DEET and the sunscreen oxybenzone from topical skin application.

    Science.gov (United States)

    Kasichayanula, Sreeneeranj; House, James D; Wang, Tao; Gu, Xiaochen

    2007-09-01

    The synergistic percutaneous enhancement between insect repellent DEET and sunscreen oxybenzone has been proven in our laboratory using a series of in vitro diffusion studies. In this study, we carried out an in vivo study to characterize skin permeation profiles from topical skin application of three commercially available repellent and sunscreen preparations. The correlation between skin disposition and drug metabolism was attempted by using data collected. Both DEET and oxybenzone permeated across the skin after the application and achieved substantial systemic absorption. Combined use of DEET and oxybenzone significantly enhanced the percutaneous penetration percentages (ranging 36-108%) due to mutual enhancement effects. Skin disposition indicated that DEET produced a faster transdermal permeation rate and higher systemic absorption extent, but oxybenzone formed a concentrated depot within the skin and delivered the content slowly over the time. In vivo AUCP/MRT of DEET and oxybenzone was increased by 37%/17% and 63%/10% when the two compounds were used together. No DEET was detected from the urine samples 48 h after the application. Tape stripping seemed to be a satisfactory approach for quantitative assessment of DEET and oxybenzone penetration into the stratum corneum. It was also concluded that pharmacological and toxicological perspectives from concurrent application of insect repellent and sunscreen products require further evaluation to ensure use efficacy and safety of these common consumer healthcare products.

  2. REPELLERS FOR MULTIFUNCTIONS OF SEMI-BORNOLOGICAL SPACES

    Institute of Scientific and Technical Information of China (English)

    M.R. Molaei; T. Waezizadeh

    2008-01-01

    In this article the notion of repeller for multifunctions from the viewpoints of semi-bornological spaces is considered. The concept of lower semi-continuous multifunc-tions is extended by the use of semi-bornological spaces. Semi-bornological vector spaces are studied. The notion of conjugacy for semi-bornological multifunctions is considered. The persistence of repeller under conjugate relation is proved.

  3. DEET Insect Repellent: Effects on Thermoregulatory Sweating and Physiological Strain

    Science.gov (United States)

    2011-01-01

    standard skin repellent, as it is effective against a wide variety of disease-transmitting insects, including mosquitoes, flies, fleas , ticks and chigger...evaporation, thus impeding evaporative heat loss. To our knowledge, only one study has experimentally examined the impact of an insect repellent on...body fat was then calculated using the Siri equation (1993). During heat acclimation and all experimental testing sessions, heart rate (HR) was

  4. Field trial of five repellent formulations against mosquitoes in Ahero, Kenya.

    Science.gov (United States)

    Sherwood, Van; Kioko, Elizabeth; Kasili, Sichangi; Ngumbi, Philip; Hollingdale, Michael R

    2009-01-01

    Twelve volunteers, using one leg for repellent application and the other leg as a control, field-tested 5 insect repellent formulations--Avon's (New York, NY) SS220 Spray, SS220 Lotion, and Bayrepel Lotion, and SC Johnson's (Racine, Wisconsin) Autan Bayrepel Lotion--against the standard N,N-diethyl-3-methyl-benzamide (deet) in a rice-growing district near Kisumu, western Kenya, in 2 trials in May and June 2004. In addition to a control leg for each volunteer, an additional control was introduced into the study by the use of a sixth repellent, a "null repellent," which was literally a treatment application of no repellent at all. The 5 active repellent formulations were uniformly applied at the maximum Environmental Protection Agency recommended dose of 1.5 g per 600 cm2 in the first trial and half that dose in the second trial, and none of them failed during the nightly 12-hour test period over 6 consecutive days, May 19 through May 24, 2004, and June 14 through June 19, 2004. However, the repellent control legs demonstrated a statistically significant increased landing rate compared to both the null repellent and the null repellent control leg. This suggests that, in this approach, active repellents increased the capture rate on an adjacent control leg compared to null controls. A single human volunteer can act as his/her own control provided null treatment controls are included.

  5. Efficacy of traps, lures, and repellents for Xylosandrus compactus (Coleoptera: Curculionidae) and other ambrosia beetles on Coffea arabica plantations and Acacia koa nurseries in Hawaii

    Science.gov (United States)

    E. G. Burbano; M.G. Wright; N.E. Gillette; S. Mori; N. Dudley; N. Jones; M. Kaufmann

    2012-01-01

    The black twig borer, Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), is a pest of coffee and many endemic Hawaiian plants. Traps baited with chemical attractants commonly are used to capture ambrosia beetles for purposes of monitoring, studying population dynamics, predicting outbreaks, and mass trapping to reduce damage...

  6. Neurophysiological and behavioral responses of gypsy moth larvae to insect repellents: DEET, IR3535, and picaridin.

    Directory of Open Access Journals (Sweden)

    Jillian L Sanford

    Full Text Available The interactions between insect repellents and the olfactory system have been widely studied, however relatively little is known about the effects of repellents on the gustatory system of insects. In this study, we show that the gustatory receptor neuron (GRN located in the medial styloconic sensilla on the maxillary palps of gypsy moth larvae, and known to be sensitive to feeding deterrents, also responds to the insect repellents DEET, IR3535, and picaridin. These repellents did not elicit responses in the lateral styloconic sensilla. Moreover, behavioral studies demonstrated that each repellent deterred feeding. This is the first study to show perception of insect repellents by the gustatory system of a lepidopteran larva and suggests that detection of a range of bitter or aversive compounds may be a broadly conserved feature among insects.

  7. Do topical repellents divert mosquitoes within a community? Health equity implications of topical repellents as a mosquito bite prevention tool.

    Science.gov (United States)

    Maia, Marta Ferreira; Onyango, Sangoro Peter; Thele, Max; Simfukwe, Emmanuel Titus; Turner, Elizabeth Louise; Moore, Sarah Jane

    2013-01-01

    Repellents do not kill mosquitoes--they simply reduce human-vector contact. Thus it is possible that individuals who do not use repellents but dwell close to repellent users experience more bites than otherwise. The objective of this study was to measure if diversion occurs from households that use repellents to those that do not use repellents. The study was performed in three Tanzanian villages using 15%-DEET and placebo lotions. All households were given LLINs. Three coverage scenarios were investigated: complete coverage (all households were given 15%-DEET), incomplete coverage (80% of households were given 15%-DEET and 20% placebo) and no coverage (all households were given placebo). A crossover study design was used and coverage scenarios were rotated weekly over a period of ten weeks. The placebo lotion was randomly allocated to households in the incomplete coverage scenario. The level of compliance was reported to be close to 100%. Mosquito densities were measured through aspiration of resting mosquitoes. Data were analysed using negative binomial regression models. Repellent-users had consistently fewer mosquitoes in their dwellings. In villages where everybody had been given 15%-DEET, resting mosquito densities were fewer than half that of households in the no coverage scenario (Incidence Rate Ratio [IRR]=0.39 (95% confidence interval [CI]: 0.25-0.60); pmosquitoes (IRR=4.17; 95% CI: 3.08-5.65; pmosquitoes are diverted from households that use repellent to those that do not. Therefore, if repellents are to be considered for vector control, strategies to maximise coverage are required.

  8. Mitigation of water repellency in burned soils applying hydrophillic polymers

    Science.gov (United States)

    Neris, Jonay; de la Torre, Sara; Vidal-Vazquez, Eva; Lado, Marcos

    2017-04-01

    In this study, the effect of fire on water repellency was analyzed in soils from different parent materials, as well as the suitability of anionic polyacrylamide (PAM) to reduce water repellency in these soils. Samples were collected in four different sites where wildfires took place: two in the Canary Islands, with soils developed on volcanic materials, and two in Galicia (NW Spain), with soils developed on plutonic rocks. In Galicia, two soil samples were collected in each site, one in the burnt area and one in an adjacent unburnt area. In the Canary Islands, four samples were collected from each site, three inside the burnt area where the soils were affected by different fire intensities, and one in an unburnt adjacent area. Samples were air-dried and sieved by a 2-mm mesh sieve. Water repellency was measured using the Water Drop Penetration Time test. An amount of 10 g of soil was placed in a tray. Five drops of deionized water were place on the soil surface with a pipette, and the time for each drop to fully penetrate into the soil was recorded. PAM solution was applied to the burnt soils simulating a field application rate of 1gm-2. The polymer used was Superfloc A-110 (Kemira Water Solutions BV, Holland) with 1x107 Da molecular weigth and 15% hydrolysis. PAM was sprayed on the soil surface as solution with a concentration 0.2 g/L. After the application, the samples were dried and the WDPT test was performed. Three replicates for each treatment and soil were used, and the treatments included: dry soil, dry soil after a wetting treatment, dry PAM-treated soil. The results showed that water repellency was modified by fire differently in the various soils. In hydrophilic soils and soils with low water repellency, water repellency was increased after the action of fire. In soils with noticeable initial water repellency, this was reduced or eliminated after the fire. Wetting repellent soils caused a decrease in water repellency most probably because of the spatial

  9. 4种不同液体蚊香在野外对流行性乙型脑炎媒介控制效果研究%Research on the efficacy of four kinds of electric liquid repellents for the Japanese encephalitis vectors in the field

    Institute of Scientific and Technical Information of China (English)

    刘文华; 蔡松武; 吴军; 林立丰; 段金花; 邹钦

    2009-01-01

    目的 研究4种电热液体蚊香[0.12%四氟甲醚菊酯(A),0.17%四氟甲醚菊酯(B),0.86%四氟苯菊酯(C),0.86%四氟丙炔菊酯(D)]在野外对流行性乙型脑炎(乙脑)媒介的控制效果.方法 采用人诱法,比较测定控制蚊虫前、后密度的下降率,调查蚊虫密度.结果 试验主要蚊虫为传播乙脑的三带喙库蚊和致倦库蚊.蚊香样品中仅有样品A使三带喙库蚊的密度下降率>80%,样品B、C和D使三带喙库蚊密度下降率均80%,样品B使其密度下降率在70%~80%之间.结论 4种蚊香样品在现场有良好的驱避致倦库蚊和三带喙库蚊的效果,但是蚊香B的驱蚊效果要差于蚊香样品A、C、D,野外试验结果与实验室药效有差别.%Objective To test the efficacy of four kinds of electric liquid repellents (A 0.12% dimefluthrin, B 0.17% dimefluthrin, C 0.86% transfluthrin, D 0.86% prallethrin) for the Japanese encephalitis(JE) vectors in the field. Methods The landing count method was used to the investigation of mosquito density before and after treatment by electric liquid repellent.Results The main species caught in the field were Culex pipiens quinquefasciatas and Cx. tritaeniorhynchas, which were the JE vector. Only sample A reached >80% population reduction of Cx. tritaeniorhynchus. Both sample B, C and D caused 80% population reduction. However, only sample B led to 70%-80% population reduction. Conclusion The tests suggest that four samples have a good repellent effect on mosquito, but the efficacy of sample B is less than that of sample A, C and D. There axe different for the control efficacy of different electric liquid repellent in the lab and the field.

  10. Effective delivery of a nematode-repellent peptide using a root-cap-specific promoter.

    Science.gov (United States)

    Lilley, Catherine J; Wang, Dong; Atkinson, Howard J; Urwin, Peter E

    2011-02-01

    The potential of the MDK4-20 promoter of Arabidopsis thaliana to direct effective transgenic expression of a secreted nematode-repellent peptide was investigated. Its expression pattern was studied in both transgenic Arabidopsis and Solanum tuberosum (potato) plants. It directed root-specific β-glucuronidase expression in both species that was chiefly localized to cells of the root cap. Use of the fluorescent timer protein dsRED-E5 established that the MDK4-20 promoter remains active for longer than the commonly used constitutive promoter CaMV35S in separated potato root border cells. Transgenic Arabidopsis lines that expressed the nematode-repellent peptide under the control of either AtMDK4-20 or CaMV35S reduced the establishment of the beet cyst nematode Heterodera schachtii. The best line using the AtMDK4-20 promoter displayed a level of resistance >80%, comparable to that of lines using the CaMV35S promoter. In transgenic potato plants, 94.9 ± 0.8% resistance to the potato cyst nematode Globodera pallida was achieved using the AtMDK4-20 promoter, compared with 34.4 ± 8.4% resistance displayed by a line expressing the repellent peptide from the CaMV35S promoter. These results establish the potential of the AtMDK4-20 promoter to limit expression of a repellent peptide whilst maintaining or even improving the efficacy of the cyst-nematode defence.

  11. Using Ethanol to Investigate Dynamic Soil Water Repellency

    Science.gov (United States)

    Smith, James E.; Beatty, Sarah M.

    2016-04-01

    Large gaps remain in our fundamental understanding of the behaviour of water in dynamically repellent soils. By investigating these systems using other miscible fluids that minimize or eliminate repellency, e.g. ethanol, we seek to better understand and quantify soil water repellency. The advantages of the enhanced wettability of water repellent soils to other miscible fluids, however, come with complications including shifts in effective pore water pressures induced through variable interfacial tensions as well as differences in fluid mobility due to variable fluid viscosities and densities. With these considerations in mind, we compare and contrast the observed behaviours of fluid infiltration and retention in dynamically hydrophobic soils and hydrophilic soils. We conducted field and laboratory studies using tension disc infiltrometers along with water and ethanol solutions to investigate dynamic repellency in post-wildfire soils from Northern Ontario, Canada. Tension infiltrometers maintain a constant negative liquid pressure at the surface which proved to be useful for isolating wettable behaviours sensitive to dynamic changes in wettability. We present the data and system conceptualised and explained through contact angle dynamics and variable fractional wettability of the soil. The limitations of extending hydrophilic concepts and hydraulic functions to hydrophobic soils are discussed along with persistent challenges to advance our ability to simulate and predict system behaviours in naturally occurring water repellent soils.

  12. Repellents Against Land Leeches for Military Use

    Directory of Open Access Journals (Sweden)

    T. Koshy

    1967-05-01

    Full Text Available A short account of the habits and nature of depredations of the leeches in the Himalayan region is given. The requirements for a leech repellent, to be of use in a hot humid and rainy area are stressed. A brief survey of the repellents and the need for their suitable screening for use in this area is made. Mention is made of some newer insect and mite repellents, which are likely to prove leech repellents as well.It is suggested that emphasis should be made on the choice of a impregnated repellent for military use in the area rather than on a 'skin repellent.

  13. EFFECTS OF MOSQUITO REPELLENTS ON PULMONARY FUNCTIONS

    Directory of Open Access Journals (Sweden)

    Venkatesh

    2014-08-01

    Full Text Available Mosquito bite transmits diseases like Malaria, Filaria, Dengue etc. and usage of repellents is very common and has been in use for a long time. The smoke contains Polyaromatic Hydrocarbons, Aldehydes and Ketones. Review of literature has shown ill effects of this smoke. Hence we intended to study the effect of mosquito repellents on lung functions. This study would be important to create awareness regarding usage of mosquito repellent and to adapt to non-harmful methods of preventing mosquito bites. PFT parameters FVC, FEV1, FEV1/ FVC %, FEF 25-75 and PEFR were recorded in mosquito coil users, liquidator’s users and controls that used neither. It was found that FVC and FEV1 were significantly less in coil and liquidators users compared to controls (P < 0.05. Also it was found that in both coil users and liquidator users FVC, FEV1, FEF 25 -75 and PEFR and showed progressive decline with increased duration of usage (P < 0.05. Hence it was concluded that mosquito coils and liquidators can cause progressive decline in lung functions. Alternative methods to combat mosquito menace, like personal and environmental hygiene and non-chemical methods of protection are therefore recommended.

  14. A repellent net as a new technology to protect cabbage crops.

    Science.gov (United States)

    Martin, T; Palix, R; Kamal, A; Delétré, E; Bonafos, R; Simon, S; Ngouajio, M

    2013-08-01

    Floating row covers or insect-proof nets with fine mesh are effective at protecting vegetable crops against aphids but negatively impact plant health, especially under warm conditions. Furthermore, in control of cabbage insect pests, aphid parasitoids cannot enter the fine-mesh nets, leading to frequent aphid outbreaks. To surmount these difficulties, a 40-mesh-size repellent net treated with alphacypermethrin was studied in laboratory and field tests. Results showed both irritant and repellent effects of the alphacypermethrin-treated net on Myzus persicae (Sulzer) (Hemiptera: Aphididae) and its parasitoid Aphidius colemani (Haliday) (Hymenoptera: Braconidae). Under field conditions, there were no pests on cabbage protected with the repellent net. The repellent net allowed combining a visual and repellent barrier against aphids. Because of this additive effect, repellent nets allowed covering cabbage permanently with adequate protection against all pests.

  15. Novel protein-repellent and biofilm-repellent orthodontic cement containing 2-methacryloyloxyethyl phosphorylcholine.

    Science.gov (United States)

    Zhang, Ning; Zhang, Ke; Melo, Mary Anne S; Chen, Chen; Fouad, Ashraf F; Bai, Yuxing; Xu, Hockin H K

    2016-07-01

    The objectives of this study were to develop the first protein-repellent resin-modified glass ionomer cement (RMGI) by incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC) for orthodontic applications, and to investigate the MPC effects on protein adsorption, biofilm growth, and enamel bond strength. MPC was incorporated into RMGI at 0% (control), 1.5%, 3%, and 5% by mass. Specimens were stored in water at 37°C for 1 and 30 days. Enamel shear bond strength (SBS) was measured, and the adhesive remnant index (ARI) scores were assessed. Protein adsorption onto the specimens was determined by a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was used. The results showed that adding 3% of MPC into RMGI did not significantly reduce the SBS (p > 0.1). There was no significant loss in SBS for RMGI containing 3% MPC after water-aging for 30 days, as compared to 1 day (p > 0.1). RMGI with 3% MPC had protein adsorption that was 1/10 that of control. RMGI with 3% MPC greatly reduced the bacterial adhesion, and lactic acid production and colony-forming units of biofilms, while substantially increasing the medium solution pH containing biofilms. The protein-repellent and biofilm-repellent effects were not decreased after water-aging for 30 days. In conclusion, the MPC-containing RMGI is promising to reduce biofilms and white spot lesions without compromising orthodontic bracket-enamel bond strength. The novel protein-repellent method may have applicability to other orthodontic cements, dental composites, adhesives, sealants, and cements to repel proteins and biofilms. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 949-959, 2016.

  16. Small-scale soil water repellency in pine rizhosphere associated with ectomycorrhiza is affected by nutrient patchiness: a soil microcosms study

    Science.gov (United States)

    Lozano, Elena; Hallett, Paul; Johnson, David; Moore, Lucy; Mataix-Solera, Jorge; Jiménez-Pinilla, Patricia; Arcenegui, Victoria

    2014-05-01

    Soil water repellency (SWR) or hydrophobicity has been commonly related to organic compounds released from the roots or decomposition of different plant species (Doerr et al., 2000). In addition, fungi and microorganisms that are associated with specific plants, could also influence SWR through the production of exudates or cellular material that form hydrophobic coatings on soil surfaces (Feeney et al., 2004; Hallett and Young, 1999) or act as surfactants. Nutrient availability, microbial biomass, organic matter and specific exudates have all been associated with the development of SWR. In terms of plant productivity, these impacts can be significant as their interaction with pore structure changes at the root-soil interface regulates both water transport and storage (Sperry et al., 1998). In boreal forests, basidiomycetous fungi are known to have a large impact on the development of SWR. These fungi are important degraders of organic material and symbionts forming ectomycorrhizal fungi (EF) associations with trees. Although many researchers have suggested a strong positive impact of EF on the ability of plants to capture water from soils, their impact on SWR at the root-soil interface and spatially within soil with a patchy nutrient distribution has not yet been investigated. This study used microcosms with mycelia systems of the EF extending from Pinus sylvestris host plants. Each microcosm was incubated during 15 days and contained plastic cup with 33P under the roots. The transfer of P from the mycelium to the host plant was monitored using a radioactive tracers and a non-destructive electronic autoradiography system in another study (data not published). SWR was measured using different approaches; as repellency index, R using a microinfiltrometer with a contact radius of 0.1 mm (modified from Hallet et al., 2002) and with the water drop penetration time test (WDPT). Sorptivity and SWR were measured between 40-50 points/microcosms. Results obtained with both

  17. Moisture characteristics of water-repellent consolidants and their applicability to existing buildings

    Science.gov (United States)

    Iba, Chiemi; Fukui, Kazuma; Hokoi, Shuichi

    2016-07-01

    Water-repellent agents are considered an effective measure of preventing moisture damage in building materials. However, data on the moisture transfer characteristics of repellent materials are insufficient. This study focused on the transfer of liquid water in a porous building material and quantitatively evaluated the applicability of a water-repellent consolidant as a protection agent via water infiltration experiments and numerical analysis. The experimental results could be reproduced by treating the water-repellent consolidant as having two layers with different water conductivities.

  18. Durable Dust Repellent Coating for Metals Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Durable Dust Repellent Coating (DDRC) consists of nano-phase silica, titania, or other oxide coatings to repel dust in a vacuum environment over a wide range of...

  19. Do topical repellents divert mosquitoes within a community? Health equity implications of topical repellents as a mosquito bite prevention tool.

    Directory of Open Access Journals (Sweden)

    Marta Ferreira Maia

    Full Text Available OBJECTIVES: Repellents do not kill mosquitoes--they simply reduce human-vector contact. Thus it is possible that individuals who do not use repellents but dwell close to repellent users experience more bites than otherwise. The objective of this study was to measure if diversion occurs from households that use repellents to those that do not use repellents. METHODS: The study was performed in three Tanzanian villages using 15%-DEET and placebo lotions. All households were given LLINs. Three coverage scenarios were investigated: complete coverage (all households were given 15%-DEET, incomplete coverage (80% of households were given 15%-DEET and 20% placebo and no coverage (all households were given placebo. A crossover study design was used and coverage scenarios were rotated weekly over a period of ten weeks. The placebo lotion was randomly allocated to households in the incomplete coverage scenario. The level of compliance was reported to be close to 100%. Mosquito densities were measured through aspiration of resting mosquitoes. Data were analysed using negative binomial regression models. FINDINGS: Repellent-users had consistently fewer mosquitoes in their dwellings. In villages where everybody had been given 15%-DEET, resting mosquito densities were fewer than half that of households in the no coverage scenario (Incidence Rate Ratio [IRR]=0.39 (95% confidence interval [CI]: 0.25-0.60; p<0.001. Placebo-users living in a village where 80% of the households used 15%-DEET were likely to have over four-times more mosquitoes (IRR=4.17; 95% CI: 3.08-5.65; p<0.001 resting in their dwellings in comparison to households in a village where nobody uses repellent. CONCLUSIONS: There is evidence that high coverage of repellent use could significantly reduce man-vector contact but with incomplete coverage evidence suggests that mosquitoes are diverted from households that use repellent to those that do not. Therefore, if repellents are to be considered for

  20. Study on repellent effect of the new stored grain insect prevention apparatuses%新型储粮防虫器具的驱虫效果研究

    Institute of Scientific and Technical Information of China (English)

    李媛; 谢令德; 贺艳萍; 张嫚

    2014-01-01

    Insect prevention bags ,films and threads were made by different concentration of biological pesticide A . The repellent effect of the different insect prevention apparatuses against 3 grain pasts was measured by repellent tests.The results showed that the grain insect prevention apparatuses with the raw material of biological pesticide A had the good repellent effect .%利用生物农药A制得不同浓度的防虫袋、防虫膜及防虫线,通过驱避试验测得不同防虫器具对三种储粮害虫的驱避效果。结果表明:以生物农药A为涂料的储粮防虫器具对三种储粮害虫具有较好的驱避效果。

  1. Toxic and repellent activity of selected monoterpenoids (thymol, carvacrol and linalool) against the castor bean tick, Ixodes ricinus (Acari: Ixodidae).

    Science.gov (United States)

    Tabari, Mohaddeseh Abouhosseini; Youssefi, Mohammad Reza; Maggi, Filippo; Benelli, Giovanni

    2017-10-15

    The castor bean tick, Ixodes ricinus, is a species of medical and veterinary importance. The use of synthetic acaricides for tick control has led to development of resistance, residues in the environment and animal products, and public health concerns. In this regard, plant essential oils and their main constituents represent an appealing alternative strategy to combat ticks. The phenols thymol and carvacrol and the alcohol linalool are monoterpenoids occurring in essential oils of several aromatic and medicinal plants, such as thyme, oregano, savory, lavender and coriander. Recent studies have shown toxicity of these monoterpenoids against selected mosquito vectors and other arthropod pests. However, information on their bioactivity on I. ricinus is not available. On this basis, here we evaluated the ovicidal, larvicidal and repellency effects of these compounds against I. ricinus. Concentrations of 0.25, 0.5, 1, 2 and 5% were sprayed on the egg masses, then hatching rates were noted. Larvicidal assays were conducted on unengorged larvae, following the larval packet technique. The repellency was determined by measuring the vertical migration behavior of ticks in laboratory conditions. Carvacrol and thymol at all concentrations tested led to a significant hatching decrease, showing an efficacy higher than permethrin, whereas linalool did not cause any significant effect. In the larvae treated with carvacrol and thymol (1, 2 and 5%), mortality rates reached 100% after 24h, showing a larvicidal efficacy higher than permethrin, whereas no effect was seen in the larval groups treated with linalool. Carvacrol and thymol at all concentrations tested showed >90% repellency on I. ricinus. Linalool was scarcely effective (50.24% repellency) only at the concentration of 5%. Overall, based on these results, the phenols carvacrol and thymol can be considered as candidate ingredients for the development of novel acaricidal formulations to control the populations of I. ricinus

  2. In vitro repellency of DEET and β-citronellol against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum.

    Science.gov (United States)

    Ferreira, Lorena Lopes; Oliveira Filho, Jaires Gomes de; Mascarin, Gabriel Moura; León, Adalberto A Pérez de; Borges, Lígia Miranda Ferreira

    2017-05-30

    Rhipicephalus sanguineus sensu lato and Amblyomma sculptum can parasite humans and domestic animals and are vectors of pathogens, including zoonoses. Repellents are an important tool of tick control. This study aimed to compare the efficacy of N,N-diethyl- 3-methylbenzamide (DEET), a standard repellent, versus β-citronellol in a Petri dish bioassay. A semicircle of filter paper (31.8cm(2)) was treated with 87μl of one of four concentrations (0.200, 0.100, 0.050 and 0.025mg/cm(2)) of β-citronellol, DEET or solvent (ethanol). A head-to-head test was developed treating one side with increasing concentrations of β-citronellol as above mentioned, against the highest concentration of DEET. Besides that a blank assay was performed. Three males and three females were placed in the middle of the plate and their location was evaluated 5, 10 and 30min after the test was initiated. As a result, the time had no significant effect on repellency response of the ticks exposed to both compounds and their concentrations. The repellency response raised according with the increase of concentration. Additionally, our findings indicate that the tick A. sculptum was more sensitive to the compounds tested and β-citronellol showed a higher efficacy than DEET. In addition, β-citronellol could be formulated to protect humans and other animals from R. sanguineus s. l. and A. sculptum infestation, as well as the diseases transmitted by these species. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. What is the role played by organic matter fractions from different sieve-size particles in the development of soil water repellency? A case study using analytical pyrolysis.

    Science.gov (United States)

    Jiménez-Morillo, Nicasio T.; González-Pérez, José A.; González-Vila, Francisco J.; Zavala, Lorena M.; Jordán, Antonio; Jiménez-González, Marco A.

    2014-05-01

    1. INTRODUCTION It is known that soil water repellency (WR) is induced by organic substances covering the surface of minerals particles and aggregates or present as interstitial substances in the soil matrix. It has also been suggested that the persistence of WR is largely conditioned by specific chemical characteristics of soil organic matter (SOM). Most of these substances are abundant in ecosystems and are released into soils as exudates of roots, organic residues in decomposition, or secretions by fungi and other microorganisms. Soil free lipids correspond to a diverse collection of hydrophobic substances including complex substances as sterols, terpenes, polynuclear hydrocarbons, chlorophylls, fatty acids, waxes, and resins. Some of these organic substances, responsible of soil water repellency may be studied using analytical pyrolisis (de la Rosa et al., 2011; González-Pérez et al., 2011). This research aims to study the relation between soil WR and SOM quantity and quality, assessing the impact of organic fractions and its distribution in soil particles of different size on soil WR from sandy soils. 2. METHODS Soil samples were collected under selected species growing in sandy soils from the Doñana National Park (SW Spain), cork oak (Quercus suber, QS), eagle fern (Pteridium aquilinum, PA), pine (Pinus pinea, PP) and rockrose (Halimium halimifolium, HH). Soil WR and physical chemical characteristics including SOM content were assessed in fine earth soil samples (PA>PP>HH. A positive correlation was observed between WR from each sieve size fraction and SOM content. The most severe WR was detected in QS for all sieve size fractions, followed by the finer fractions form PA, PP and HH samples, which that also shows the highest SOM content, ranging between 20.9% (PP) and 46.9% (QS). Coarser soil fractions (1-2 mm) under PA, PP and HH showed the highest long-chain-even C numbered fatty acids (LCE-FA) in the order PP>PA>HH. No fatty acids were detected neither

  4. Neurophysiological and behavioral responses of gypsy moth larvae to insect repellents

    Science.gov (United States)

    The interactions between insect repellents and the olfactory system have been widely studied, however relatively little is known about the effects of repellents on the gustatory system of insects. In this study, we show that the gustatory receptor neuron (GRN) located in the medial styloconic sensi...

  5. Water repellency under natural conditions in sandy soils of southern Spain

    NARCIS (Netherlands)

    Moral García, F.J.; Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    The occurrence and consequences of fire-induced water repellency have been studied in several regions of Spain since 1989. The occurrence of water repellency formed under natural conditions, however, has only been described for a few areas in Spain since 1998. The purpose of the present study was to

  6. New Candidates for Plant-Based Repellents Against Aedes aegypti.

    Science.gov (United States)

    Misni, Norashiqin; Nor, Zurainee Mohamed; Ahmad, Rohani

    2016-06-01

    Based on an ethnobotanical study on use for plant species against mosquito bites in the Kota Tinggi District, Johor State, Malaysia, 3 plants selected for study, Citrus aurantifolia (leaves), Citrus grandis (fruit peel), and Alpinia galanga (rhizome), were extracted using hydrodistillation to produce essential oils. These essential oils were then formulated as a lotion using a microencapsulation process and then tested for their repellent effect against Aedes aegypti. N,N-diethyl-m-toluamide (deet) was also prepared in the same formulation and tested for repellency as controls. Four commercial plant-based repellent (KAPS(®), MozAway(®), BioZ Natural(®), and Mosiquard(®)) also were incorporated in the bioassay for comparison purposes. Bioassays revealed that at 20% concentration all repellent formulations demonstrated complete protection for 2 h and >90% for 4 h post-application. The A. galanga-based formulation provided the greatest level of protection (98.91%), which extended for 4 h post-application and was not significantly different from deet at similar concentration. When compared with commercial plant-based repellents (KAPS(®), MozAway(®), and BioZ Natural(®)), the 3 lotion formulations showed significantly better protection against Ae. aegypti bites, providing >90% protection for 4 h. In conclusion, our 3 plant-based lotion formulations provided acceptable levels of protection against host-seeking Ae. aegypti and should be developed.

  7. Mosquito repellent activity of volatile oils from selected aromatic plants.

    Science.gov (United States)

    Lalthazuali; Mathew, Nisha

    2017-02-01

    Essential oils from fresh leaves of four aromatic plants viz., Ocimum sanctum, Mentha piperita, Eucalyptus globulus and Plectranthus amboinicus were extracted by hydrodistillation. The test solutions were prepared as 20% essential oil in ethanol and positive control as 20% DEET in ethanol. Essential oil blend was prepared as 5% concentration. Nulliparous, 3-5-day-old female adult Aedes aegypti mosquitoes were used for repellency screening as per ICMR protocol. The study showed that the repellency of 20% essential oil of O. sanctum, M. piperita and P. amboinicus were comparable with that of the standard DEET (20%) as no mosquito landing on the test was observed up to 6 h. The E. globulus oil exhibited mosquito repellency only upto 1½ h. Considerable mosquito landing and feeding was displayed in negative control. In the case of the oil blend, no landing of mosquitoes was seen up to 6 h as that of positive control. The results showed that the essential oil blend from O. sanctum, M. piperita, E. globulus and P. amboinicus could repel Ae. aegypti mosquitoes or prevent from feeding as in the case of DEET even at a lower concentration of 5%. This study demonstrates the potential of essential oils from O. sanctum, M. piperita, E. globulus and P. amboinicus and their blend as mosquito repellents against Ae. aegypti, the vector of dengue, chikungunya and yellow fever.

  8. Study on property of new type effective compound repelling agent%新型高效复合防水剂的性能研究

    Institute of Scientific and Technical Information of China (English)

    幸振明; 吕子义

    2001-01-01

    以丙烯酸类化合物为主剂,萘系减水剂为辅剂组成砂浆复合防水剂,对复合防水砂浆在建筑防渗砂浆上的技术特性做了各项对比性试验研究,介绍这种复合防水剂的高效抗渗性能和相应防水砂浆的高抗渗性和良好的工作性能。%The mortar compound repelling agent is made from acrylic chemicals as principal raw material and naphthalene reducer as additive. Every item of comparison test and research for technical features of compound repelling mortar has been carried out in building anti - seepage mortar. The high effective anti - seepage property of this compound repelling agentand the high anti - seepage and.good workability of the corresponding repelling mortar havebeen presented.

  9. Percutaneous penetration and pharmacodynamics: Wash-in and wash-off of sunscreen and insect repellent.

    Science.gov (United States)

    Rodriguez, Jocelyn; Maibach, Howard I

    2016-01-01

    Increased awareness of skin cancer and mosquito-transmitted diseases has increased use of insect repellents and sunscreens. The challenge in setting recommendations for use and reapplication, especially when used concomitantly, lies in finding the balance between applying a durable product effective in withstanding natural and physical factors such as water, sweat, temperature and abrasion, while limiting percutaneous absorption and decreasing risk of potential dermal and systemic toxicity. Inorganic sunscreens show no or little percutaneous absorption or toxic effects in comparison to organic sunscreens, which show varying levels of dermal penetration and cutaneous adverse effects. An alternative to N,N-diethyl-m-toluamide (DEET), the traditional gold standard compound in insect repellents, picaridin appears as efficacious, has lower risk of toxicity, and when used simultaneously with sunscreen may decrease percutaneous absorption of both compounds. Conversely, combined use of DEET and sunscreen results in significantly higher absorption of both compounds. It is important to increase consumer awareness of "washing in" of various compounds leading to increased risk of toxicity, as well as differences in reapplication need due to "washing off" caused by water, sweat and abrasion. Although much remains to be studied, to maximize efficacy and decrease toxicity, contemporary research tools, including dermatopharmokinetics, should aid these prospective advances.

  10. Evaluation of botanicals as repellents against mosquitoes.

    Science.gov (United States)

    Das, N G; Baruah, I; Talukdar, P K; Das, S C

    2003-01-01

    Repellent properties of three plant extracts--essential oil (steam distillate) of Zanthoxylum limonella (fruits), Citrus aurantifolia (leaf) and petroleum ether extract of Z. limonella (fruits) were evaluated as repellent against Aedes (S.) albopictus mosquitoes in mustard (Dhara) and coconut (Parachute) oil base under laboratory conditions. Three concentrations--10, 20 and 30% of the repellents were evaluated. Repellents in mustard oil afforded longer protection time against the bites of Aedes (S.) albopictus mosquitoes than those in coconut oil. At 30% concentration, 296-304 min protection time was achieved by the test repellents in mustard oil base while repellents in coconut oil exhibited 223.5-245 min protection time at the same concentration. Oil of Z. limonella gave the highest protection time against the bites of Aedes (S.) albopictus mosquitoes at all the concentrations than other herbal repellents tested both in mustard and coconut oil.

  11. Mosquito repellent potential ofPithecellobium dulce leaf and seed against malaria vectorAnopheles stephensi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Mohan Rajeswary; Marimuthu Govindarajan

    2016-01-01

    Objective:To determine the repellent properties of hexane, benzene, ethyl acetate, chloroform and methanol extract ofPithecellobium dulce (P. dulce) leaf and seed against Anopheles stephensi(An. stephensi). Methods:Repellent activity assay was carried out in a net cage (45 cmí30 cmí25 cm) containing 100 blood starved female mosquitoes ofAn. stephensi. This assay was carried out in the laboratory conditions according to theWHO 2009 protocol. Plant crude extracts ofP. dulce were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control. Results: In this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the concentration of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 leaf and seed methanol extract ofP. dulceprovided over 180 min and 150 min protection, respectively. Conclusions: Crude extracts ofP. dulceexhibit the potential for controlling malaria vector mosquitoAn. stephensi.

  12. Mosquito repellent properties of Delonix elata (L. gamble (Family: Fabaceae against filariasis vector, Culex quinquefasciatus Say. (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Marimuthu Govindarajan

    2014-02-01

    Full Text Available Objective: To determine the repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Delonix elata (D. elata leaf and seed against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Evaluation was carried out in a net cage (45 cm伊30 cm伊25 cm containing 100 blood starved female mosquitoes of Cx. quinquefasciatus. Repellent activity was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of D. elata were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control. Results: In this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the strength of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 provided over 150 min and 120 min protection, respectively. Conclusions: Crude extracts of D. elata exhibit the potential for controlling Cx. quinquefasciatus, the mosquito vector of filariasis.

  13. Repellent effect of Lagenaria siceraria extracts against Culex pipiens.

    Science.gov (United States)

    Hassan, Mostafa I; Fouda, Mohamad A; Hammad, Kotb M; Tanani, Mohamad A; Shehata, Ahmed Z

    2014-04-01

    Ethanolic, acetone and petroleum ether extracts from leaves and stems of Lagenaria siceraria (Cucurbitaceae) were screened for their repellency effect against Culex pipiens L. mosquito. The repellent action of the present plant extracts were varied depending on the plant parts and the dose of extract. The petroleum ether extract of leaves showed the same repellency percent (100%) of commercial formulation, N. N.diethyl toulamide (DEET) at the higher dose (3.33 mg/cm2), while petroleum ether extract from stems exhibiting the repellent action (89.6%) at the same dose, respectively. Ethanolic extracts of leaves and stems exhibited the lowest repellent activity as it recorded (81.3% and 69.1%) at (6.67 mg/cm2), respectively. Results of this study may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection measure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  14. Odorant receptor modulation: Ternary paradigm for mode of action of insect repellents

    Science.gov (United States)

    The modulation of insect behavior for the purpose of controlling the spread of infectious diseases has been the task of a few insect repellents for which the mechanistic modes of action on odorant receptors (ORs) are unclear. Here, we study the effects of the repellents DEET and IR3535, and a novel ...

  15. Soil water repellency in an old and young pasture in relation to N application

    NARCIS (Netherlands)

    Sonneveld, M.P.W.

    2008-01-01

    Ageing of pastures is likely to affect the degree of potential water repellency in the long term, whereas seasonal variation on a shorter term affects the actual repellency of soils. A 1-year study on two pastures of different ages was conducted on a sandy soil to assess changes in the degree of

  16. Water repellency and critical soil water content in a dune sand

    NARCIS (Netherlands)

    Dekker, L.W.; Doerr, S.H.; Oostindie, K.; Ziogas, A.K.; Ritsema, C.J.

    2001-01-01

    Assessments of water repellency of soils are commonly made on air-dried or oven-dried samples, without considering the soil water content. The objectives of this study were to examine the spatial and temporal variability of soil water content, actual water repellency over short distances, and the

  17. Pre- and postfire distribution of soil water repellency in a steep chaparral watershed

    Science.gov (United States)

    K. R. Hubbert; P. M. Wohlgemuth; H. K. Preisler

    2008-01-01

    The development and nature of water repellent soils and their spatial distribution on the landscape are not well understood relative to evaluating hillslope response to fire. Soil water repellency is particularly common in chaparral communities, due in part to the coarse-textured soils, and the high resin content of the organic litter. Objectives of this study were 1)...

  18. Integration of repellents, attractants, and insecticides in a "push-pull" strategy for managing German cockroach (Dictyoptera: Blattellidae) populations.

    Science.gov (United States)

    Nalyanya, G; Moore, C B; Schal, C

    2000-05-01

    "Push-pull" is a behavior manipulation strategy in which behavior-modifying stimuli are integrated with a pest control agent. We evaluated the efficacy of an insecticide bait in combination with attractants ("pull"), repellents ("push"), or both ("push-pull") using a hydramethylnon-based bait, feces-contaminated surfaces as an attractant, and methyl neodecanamide-treated surfaces to repel cockroaches. Both adult males and first-instar German cockroaches, Blattella germanica (L.), chose shelters nearest the attractant-treated surfaces and farthest from the repellent-treated surfaces. Food consumption was highest from food nearest the preferred shelters, and mortality was highest when the insecticide bait was near the preferred shelter. These patterns were more apparent in first instars than in adults. Our results from large arena studies in the laboratory show that the push-pull strategy can be used to displace pests from resources or commodities that are to be protected, and simultaneously lure the pest to an attractant source coupled with a pest control agent. Concentrating cockroaches into a limited area should facilitate the precision-targeting of the pest population and promises to reduce insecticide use.

  19. Repellent activity of desiccant dusts and conidia of the entomopathogenic fungus Beauveria bassiana when tested against poultry red mites (Dermanyssus gallinae) in laboratory experiments

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2016-01-01

    on both dose and relative humidity (RH). However, one desiccant dust was significantly less repellent compared to other dusts with similar levels of efficacy. Further, dry conidia of the fungus Beauveria bassiana were also shown to be repellent to poultry red mites, both when applied on its own and when...

  20. Super toner and ink repellent superoleophobic surface.

    Science.gov (United States)

    Zhao, Hong; Law, Kock-Yee

    2012-08-01

    Offset of imaging material from a fuser surface to paper during fusing is highly undesirable in printing. Here the wetting and repellent characteristics of three imaging materials (a solid wax ink, a waxy polyester toner, and a polyester toner) in their molten states have been studied on three model print surfaces: a transparency (surrogate for paper), a PTFE film, and a model superoleophobic surface, with the aim of assessing their performance in fusing. The superoleophobic surface, with water and hexadecane contact angles of ∼156° and sliding angles at ∼10°, comprises 3 μm diameter pillar arrays on silicon wafer and was fabricated by photolithography followed by surface modification with a fluorosilane. The contact angles of the three imaging materials range from 40 to 79° on the transparency and the sessile drops do not slide even at 90° tilted angle, indicating that they all wet, adhere, and pin on the transparency. Although the contact angles of the three imaging materials are slightly higher (63-85°) on PTFE, the sessile drops do not slide on PTFE either. Because PTFE is widely used as a fuser surface material in combination with different waxy imaging materials commercially, we attribute the successful implementation of PTFE to the use of the wax additive. With the superoleophobic surface, there is a dramatic increase in advancing and static contact angles for all three imaging materials. The advancing and static contact angles are in the 150-168° range for waxy toner, indicative of superhigh repellency. Although the advancing and static contact angles for the polyester toner decrease slightly at 147 and 130°, respectively, the repellency is still very high. More importantly, the sessile drops of all three imaging materials are mobile upon tilting and they all have high receding contact angles. The overall results suggest that the adhesion between the superoleophobic surface and the ink and toner materials are very small relative to those with

  1. Physicians, Primary Caregivers and Topical Repellent: All Under-Utilised Resources in Stopping Dengue Virus Transmission in Affected Households.

    Directory of Open Access Journals (Sweden)

    Nguyet Minh Nguyen

    2016-05-01

    Full Text Available Primary health care facilities frequently manage dengue cases on an ambulatory basis for the duration of the patient's illness. There is a great opportunity for specific messaging, aimed to reduce dengue virus (DENV transmission in and around the home, to be directly targeted toward this high-risk ambulatory patient group, as part of an integrated approach to dengue management. The extent however, to which physicians understand, and can themselves effectively communicate strategies to stop focal DENV transmission around an ambulatory dengue case is unknown; the matter of patient comprehension and recollection then ensues. In addition, the effectiveness of N,N-diethyl-3-methylbenzamide (DEET-based insect repellent in protecting dengue patients from Aedes aegypti mosquitoes' bites has not been investigated.A knowledge, attitude and practice (KAP survey, focusing on the mechanisms of DENV transmission and prevention, was performed using semi-structured questionnaires. This survey was targeted towards the patients and family members providing supportive care, and physicians routinely involved in dengue patient management in Southern Vietnam. An additional clinical observational study was conducted to measure the efficacy of a widely-used 13% DEET-based insect repellent to repel Ae. aegypti mosquitoes from the forearms of dengue cases and matched healthy controls.Among both the physician (n = 50 and patient (n = 49 groups there were several respondents lacking a coherent understanding of DENV transmission, leading to some inappropriate attitudes and inadequate acute preventive practices in the household. The application of insect repellent to protect patients and their relatives from mosquito bites was frequently recommended by majority of physicians (78% participating in the survey. Nevertheless, our tested topical application of 13% DEET conferred only ~1hr median protection time from Ae. aegypti landing. This is notably shorter than that

  2. Evaluation of botanicals as repellents against mosquitoes

    Directory of Open Access Journals (Sweden)

    N.G. Das, I. Baruah, P.K. Talukdar & S.C. Das

    2003-03-01

    Full Text Available Repellent properties of three plant extracts—essential oil (steam distillate of Zanthoxylumlimonella (fruits, Citrus aurantifolia (leaf and petroleum ether extract of Z. limonella (fruitswere evaluated as repellent against Aedes (S. albopictus mosquitoes in mustard (Dhara and coconut(Parachute oil base under laboratory conditions. Three concentrations—10, 20 and 30% of therepellents were evaluated. Repellents in mustard oil afforded longer protection time against thebites of Aedes (S. albopictus mosquitoes than those in coconut oil. At 30% concentration, 296–304 min protection time was achieved by the test repellents in mustard oil base while repellents incoconut oil exhibited 223.5–245 min protection time at the same concentration. Oil of Z. limonellagave the highest protection time against the bites of Aedes (S. albopictus mosquitoes at all theconcentrations than other herbal repellents tested both in mustard and coconut oil.

  3. Field evaluation of the Off! Clip-on Mosquito Repellent (metofluthrin) against Aedes albopictus and Aedes taeniorhynchus (Diptera: Culicidae) in northeastern Florida.

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A; Smith, Michael L; Gaines, Marcia K; Weaver, James H; Debboun, Mustapha

    2012-05-01

    Repellent efficacy of the Off! Clip-on Mosquito Repellent device (S. C. Johnson and Son, Inc., Racine, WI) containing Metofluthrin was evaluated on six human volunteers against the container-breeding mosquito Aedes albopictus (Skuse) and the salt marsh mosquito Aedes taeniorhynchus (Wiedemann) at two field locations in northeastern Florida. The device repelled mosquitoes by releasing a vaporized form of the pyrethroid insecticide metofluthrin ([AI] 31.2%) and provided 70% protection from Ae. albopictus bites for > 3 h. For the second field trial, a repellent device that was used in the first trial was tested after being open for >1 wk. This device provided 79% protection from Ae. taeniorhynchus bites for 3 h. Our field results showed that the repellent device was 70 and 79% effective at repelling Ae. albopictus and Ae. taeniorhynchus from human test subjects in both field locations in northeastern Florida.

  4. Basic soil properties as a factor controlling the occurrence and intensity of water repellency in rankers of the White Carpathians

    Directory of Open Access Journals (Sweden)

    Kořenková Lucia

    2015-09-01

    Full Text Available Water repellency in soils is controlled by many different factors, basic physical and chemical properties might be considered the crucial ones. For the purpose of this study, 12 sites were selected and sampled (0–20 cm depth in the White Carpathians. Repellency tests were conducted under laboratory conditions in triplicate using water drop penetration time (WDPT test and the molarity of ethanol droplet (MED test. Results of WDPT measurements showed that three samples were marked by slight to extreme water repellency. Regarding the relationship between WDPT/MED and tested soil properties, the highest value of correlation coefficient was calculated for soil organic carbon (r = 0.706; p < 0.05, suggesting there is a positive, statistically significant correlation between repellency severity and total carbon content. A negative relationship between repellency and soil reaction/silt/silt + clay contents of studied soils was found. Samples taken from the surface horizon of arable soils showed no repellency.

  5. The role of repellents and hydrophobins in Ustilago maydis

    NARCIS (Netherlands)

    Teertstra, W.R.

    2009-01-01

    Ustilago maydis is an important model organism to study fungal pathogenicity. U. maydis can grow yeast-like and filamentous. In the latter form this fungus infects maize. In my Thesis the expression and function of hydrophobins and repellents of U. maydis were studied. Hydrophobins are produced by f

  6. The role of repellents and hydrophobins in Ustilago maydis

    NARCIS (Netherlands)

    Teertstra, W.R.

    2009-01-01

    Ustilago maydis is an important model organism to study fungal pathogenicity. U. maydis can grow yeast-like and filamentous. In the latter form this fungus infects maize. In my Thesis the expression and function of hydrophobins and repellents of U. maydis were studied. Hydrophobins are produced by f

  7. Olfactory responses of the antennal trichoid sensilla to chemical repellents in the mosquito, Culex quinquefasciatus.

    Science.gov (United States)

    Liu, Feng; Chen, Li; Appel, Arthur G; Liu, Nannan

    2013-11-01

    Insect repellents are widely used to protect against insect bites and thus prevent allergic reaction and the spread of disease. To gain insight into the mosquito's response to chemicals repellents, we investigated the interaction between the olfactory system of the mosquito Culex quinquefasciatus Say and chemical repellents using single sensillum recording. The interactions of 50 repellent chemicals with olfactory receptor neurons were measured in six different types of mosquito sensilla: long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBT-I), short blunt trichoid II (SBT-II), short blunt trichoid-curved (SBT-C), and grooved peg (GP). A single olfactory neuron reacted to the chemical repellents in each of the sensilla except for SBT-I and SBT-II, where two neurons were involved. Other than LST and GP, which showed no or very weak responses to the repellents tested, all the sensilla showed significant excitatory responses to certain types of repellents. Terpene-derived chemicals such as eucalyptol, α-pinene, and camphor, stimulated olfactory receptor neurons in a dose-dependent manner and mosquitoes responded more strongly to terpene-derived chemical repellents than to non-terpene-derived chemicals such as dimethyl phthalate. Mosquitoes also exhibited a similar response to stereoisomers of chemicals such as (-)-β-pinene versus (+)-β-pinene, and (-)-menthone versus (+)-menthone. This study not only demonstrates the effects of chemical repellents on the mosquito olfactory system but also provides important information that will assist those screening new mosquito repellents and designing new mosquito control agents.

  8. Natural Product Studies of U. S. Endangered Plants: Volatile Fraction of Lindera melissifolia (lauraceae) repels Mosquitoes and Ticks

    Science.gov (United States)

    The number of endangered plant species in the United States is significant yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are hematophagous vectors for significant pathogenic diseases and key measures to lower their associated morbidity rates include the use of p...

  9. Repellent activity of essential oils against cockroaches (Dictyoptera: Blattidae, Blattellidae, and Blaberidae) in Thailand.

    Science.gov (United States)

    Thavara, Usavadee; Tawatsin, Apiwat; Bhakdeenuan, Payu; Wongsinkongman, Prapai; Boonruad, Thidarat; Bansiddhi, Jaree; Chavalittumrong, Pranee; Komalamisra, Narumon; Siriyasatien, Padet; Mulla, Mir S

    2007-07-01

    Seven commercial essential oils extracted from the plant species Boesenbergia rotunda (L.) Mansf., Citrus hystrix DC., Curcuma longa L., Litsea cubeba (Lour.) Pers., Piper nigrum L., Psidium guajava L. and Zingiber officinale Roscoe, and naphthalene as a control, were evaluated for repellent activity against the three cockroach species Periplaneta americana (L.), Blattella germanica (L.) and Neostylopyga rhombifolia (Stoll) under laboratory conditions. The essential oil derived from Citrus hystrix showed the best repellency over other candidate essential oils and naphthalene. The essential oil of Citrus hystrix exhibited complete repellency (100%) against P. americana and B. germanica, and also showed the highest repellency (among the essential oils tested) of about 87.5% against N. rhombifolia under laboratory conditions. In the field, Citrus hystrix essential oil formulated as a 20% active ingredient in ethanol and some additives provided satisfactory repellency of up to 86% reduction in cockroaches, mostly P. americana and N. rhombifolia with a residual effect lasting a week after treatment. Citrus hystrix essential oil has good potential for being used as a cockroach repellent. Further improvements in efficacy and residual activity may be realized with appropriate formulations.

  10. Water-repellent soil and its relationship to granularity, surface roughness and hydrophobicity: a materials science view

    OpenAIRE

    McHale, Glen; Newton, Michael; Shirtcliffe, Neil

    2005-01-01

    Considerable soil water repellency has been observed at a wide range of locations worldwide. The soil exhibiting water repellency is found within the upper part of the soil profile. The reduced rate of water infiltration into these soils leads to severe run-off erosion, and reduction of plant growth. Soil water repellency is promoted by drying of soil, and can be induced by fire or intense heating of soil containing hydrophobic organic matter. Recent studies outside of soil science have shown...

  11. DEET mosquito repellent sold through social marketing provides personal protection against malaria in an area of all-night mosquito biting and partial coverage of insecticide-treated nets: a case-control study of effectiveness.

    Science.gov (United States)

    Rowland, Mark; Freeman, Tim; Downey, Gerald; Hadi, Abdul; Saeed, Mohammed

    2004-03-01

    DEET (diethyl-3-methylbenzamide), the widely used mosquito repellent, has the potential to prevent malarial infection but hitherto there has been no study demonstrating this possibility during normal everyday use. Mosbar, a repellent soap containing DEET, was promoted through social marketing in villages in eastern Afghanistan. This was followed up with a case-control study of effectiveness against malarial infection conducted through local clinics. Mosbar was purchased by 43% of households. Reported use of insecticide-treated nets (ITNs) was 65% among the control group. There was a strong association between Mosbar use and ITN use, as 81% of Mosbar users also possessed ITN. The use of Mosbar was associated with a 45% reduction in the odds of malaria (95% CI: -11% to 72%, P=0.08) after adjusting for ITN and other unmatched factors. Ownership of ITNs was associated with a 46% reduction in the odds of malaria (95% CI: 12% to 67%, P=0.013) after adjusting for Mosbar and other unmatched factors. The greatest reduction in the odds of malaria was associated with combined use of Mosbar and ITN (69% reduction, 95% CI: 28% to 87%, P=0.007). The association between recalled use of Mosbar 10 days ago (nearer the time of infection) and reduction in malarial infections (adjusted odds ratio 0.08, 95% CI: 0.01-0.61, P=0.001) was significantly stronger than that shown by current use of Mosbar. Most purchasers of Mosbar were satisfied with the product (74%), although a minority said they preferred to use only ITN (8%). The local mosquito vectors, Anopheles stephensi and A. nigerrimus, started biting shortly after dusk and continued biting until early morning. It was shown that Mosbar prevented biting throughout this period. In regions where mosquito vectors bite during evening and night, repellents could have a useful supplementary role to ITN and their use should be more widely encouraged.

  12. Exponential increase of publications related to soil water repellency

    NARCIS (Netherlands)

    Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Soil water repellency is much more wide-spread than formerly thought. During the last decades, it has been a topic of study for soil scientists and hydrologists in at least 21 States of the USA, in Canada, Australia, New Zealand, Mexico, Colombia, Chile, Congo, Nepal, India, Hong Kong, Taiwan, China

  13. Olfactory responses to attractants and repellents in tsetse

    NARCIS (Netherlands)

    Voskamp, KE; Everaarts, E; Den Otter, CJ

    1999-01-01

    The aims of this study were to investigate how antennal olfactory cells of tsetse (Diptera: Glossinidae) code odour quality and how they are able to discriminate between attractive and repellent odours. For Glossina pallidipes Austen, a survey is presented of the cells' responses to attractive (1-oc

  14. Exponential increase of publications related to soil water repellency

    NARCIS (Netherlands)

    Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Soil water repellency is much more wide-spread than formerly thought. During the last decades, it has been a topic of study for soil scientists and hydrologists in at least 21 States of the USA, in Canada, Australia, New Zealand, Mexico, Colombia, Chile, Congo, Nepal, India, Hong Kong, Taiwan,

  15. Soil surfactant stops water repellency and preferential flow paths

    NARCIS (Netherlands)

    Oostindie, K.; Dekker, L.W.; Wesseling, J.G.; Ritsema, C.J.

    2008-01-01

    This study reports the effects of a soil surfactant on reduction and prevention of water repellency and preferential flow paths in a sandy soil of a golf course fairway, located at Bosch en Duin near Utrecht, the Netherlands. The golf course is constructed on inland dunes composed of fine sand with

  16. Study Skills Course Impact on Academic Self-Efficacy

    Science.gov (United States)

    Wernersbach, Brenna M.; Crowley, Susan L.; Bates, Scott C.; Rosenthal, Carol

    2014-01-01

    Although study skills courses improve student retention, the impact of study skills courses on students' academic self-efficacy has not been investigated. The present study examined pre- and posttest levels of academic self-efficacy in college students enrolled in a study skills course (n = 126) compared to students enrolled in a general education…

  17. Spatial and temporal variability of water repellency in a sandy soil contaminated with tar oil and heavy metals.

    Science.gov (United States)

    Buczko, Uwe; Bens, Oliver; Durner, Wolfgang

    2006-12-15

    Water repellency can induce preferential flow and thus affect water flow and contaminant transport at hazardous waste sites. Since the spatial patterns of water repellency are mostly unknown, it is problematic to use numerical transport models to predict leachate composition. In this study, the spatial variability of soil water repellency was studied at an industrial site contaminated with tar oil, chromium, copper and arsenic. The persistence of water repellency was assessed by the water drop penetration time (WDPT), and the degree of water repellency was quantified by the ethanol percentage (EP) test. Measurements were made at the soil surface along 3.5-12.1 m long transects at different times between March and October 2002. The spatial variability of WDPT, EP, water content, and organic matter content was quantified by variogram analyses. Both the persistence and the degree of water repellency varied seasonally, with the highest water repellency during the summer months. The correlation lengths of WDPT values ranged between 16 and 406 cm, whereas EP values showed no spatial correlation. For field-moist samples, a critical soil water threshold, below which water repellency prevails, was estimated to be 2.5-4%. For oven dry samples, the WDPT values were dependent on the water content prior to drying. The wide range of correlation lengths and the temporal dynamics of spatial repellency patterns suggest that simulations of solute leaching must consider the spatial and temporal variability of soil hydrophobic properties.

  18. Piperitenone oxide as toxic, repellent, and reproduction retardant toward malarial vector Anopheles stephensi (Diptera: Anophelinae).

    Science.gov (United States)

    Tripathi, Arun K; Prajapati, Veena; Ahmad, Ateeque; Aggarwal, Kishan K; Khanuja, Suman P S

    2004-07-01

    Anopheles stephensi (Liston) is a well-known vector of malarial parasite in tropical countries. The developing trend of resistance in mosquitoes toward synthetic mosquitocidal agents makes their management extremely difficult. Effectiveness of essential oils with aroma therapeutic values seems to be an emerging tool to combat this vector. Piperitenone oxide isolated from essential oil of a new genotype, Mentha spicata L. variety viridis, has been evaluated for larvicidal, ovicidal, oviposition-deterrent, developmental toxicity, and repellent properties against various stages of A. stephensi. The results indicated the higher efficacy of piperitenone oxide than the crude essential oil of M. spicata variety viridis in all the bioassay experiments. The lethal response of piperitenone oxide and the oil toward fourth instar larvae showed LD50 values of 61.64 and 82.95 microg/ml, respectively. Female adults of A. stephensi exposed to the oil laid approximately 42 times less number of eggs at the dose of 60.0 microg/ml as compared with control, whereas exposure of piperitenone oxide at the same dose completely inhibited the oviposition. Furthermore, piperitenone oxide also completely inhibited egg hatching at the dose of 75.0 microg/ml in ovicidal assay. Developmental toxicity studies showed the significant developmental inhibition potential of the compound and oil. Additionally, piperitenone oxide was found to be highly toxic and repellent toward adults of A. stephensi as compared with oil.

  19. Relationship between water repellency and native and petroleum-derived organic carbon in soils.

    Science.gov (United States)

    Roy, J L; McGill, W B; Lowen, H A; Johnson, R L

    2003-01-01

    Some soils develop severe and persistent water repellency following contamination with crude oil. This study was conducted to characterize and compare the spatial distribution of soil water repellency and residual oil contamination at 12 such sites. The molarity of ethanol droplet (MED) test was used to assess soil water repellency and the content of dichloromethane-extractable organics (DEO) was used to quantify residual oil in soil. We found a relatively strong positive correlation between MED and DEO in soil (r2 = 0.74). Both variables tended to decrease abruptly with depth at 11 of the 12 study sites. Dichloromethane-extractable organics similarly decreased with depth in control adjacent soil (MED = 0 M), but from an average concentration one to two orders of magnitude lower than in water-repellent soil. Using data from corresponding control adjacent and water-repellent soils, we determined that approximately 29 and 10% of measured total organic carbon in water-repellent A- and B-horizon soil, respectively, consists of dichloromethane-insoluble organic carbon of petroleum origin. We propose that this fraction contains most of the causative agents of soil water repellency at the studied sites.

  20. Chapter 12: spatial or area repellents

    Science.gov (United States)

    Spatial repellents a three-dimensional zone of protection around a host from attacks by biting arthropods. This chapter reviews current knowledge and outlines future directions for utilization of spatial repellents. Current knowledge includes the kinds of products, both active and passive devices,...

  1. Structural optimization of super-repellent surfaces

    DEFF Research Database (Denmark)

    Cavalli, Andrea; Bøggild, Peter; Okkels, Fridolin

    2013-01-01

    Micro-patterning is an effective way to achieve surfaces with extreme liquid repellency. This technique does not rely on chemical coatings and is therefore a promising concept for application in food processing and bio-compatibile coatings. This super-repellent behaviour is obtained by suspending...

  2. Self-Efficacy and Statistics Performance among Sport Studies Students

    Science.gov (United States)

    Lane, Andrew M.; Hall, Ross; Lane, John

    2004-01-01

    The present study explored predictive paths between performance accomplishments, self-efficacy, and performance among Sport Studies students taking a Level 1 statistics module. Fifty-eight Level 1 Sport Studies undergraduate degree students completed a 44-item self-efficacy measure and an assessment of perceived academic success at the start of…

  3. Potential of eucalyptus oil as repellent against house rat, Rattus rattus.

    Science.gov (United States)

    Singla, Neena; Thind, Ramandeep Kaur; Mahal, Amrit Kaur

    2014-01-01

    Rodent repellents are chemicals which by taste or odour or possibly by both will prevent animal from feeding or gnawing. Such substances may be used in protecting an area from rodent infestation or in protecting packaged food, packing materials, electric cables, and other important vulnerable materials. Mature and healthy house rat, Rattus rattus of both sexes, was exposed to 5, 10, and 20% eucalyptus oil applied as spray in laboratory pens in bichoice tests. Each concentration was applied through three different modes of application, that is, daily, once, and alternatively in a week. Repellent effect of the oil was assessed based on food consumption from treated and untreated sides for four days. In overall, food consumption was significantly (P repellent effect of the oil at all the three concentrations tested. Repellent effect of the oil was, however, not found to differ significantly between the two sexes. Percent repellency in both male and female rats was apparently more with daily application of 5 and 10% eucalyptus oil. Present studies reveal the potential of eucalyptus oil in repelling away R. rattus; however, further studies may be conducted to enhance the persistence of repellent effect for longer period of time.

  4. Quantitative structure-activity relationship of botanical sesquiterpenes: spatial and contact repellency to the yellow fever mosquito, Aedes aegypti.

    Science.gov (United States)

    Paluch, Gretchen; Grodnitzky, Justin; Bartholomay, Lyric; Coats, Joel

    2009-08-26

    The plant terpenoids encompass a diversity of structures and have many functional roles in nature, including protection against pest arthropods. Previous studies in this laboratory have identified naturally occurring sesquiterpenes contained in essential oils from two plants, amyris (Amyris balsamifera) and Siam-wood (Fokienia hodginsii), that are significantly repellent to a spectrum of arthropod pests. In efforts to further examine the biological activity of this class of compounds 12 of these plant-derived sesquiterpenes have been isolated, purified, and assayed for spatial and contact repellency against the yellow fever mosquito, Aedes aegypti . These data were used to develop quantitative structure-activity relationships that identified key properties of the sesquiterpene molecule, including electronic and structural parameters that were used to predict optimal repellent activity. There were notable similarities in the models developed for spatial repellency over five time points and for contact repellency. Vapor pressure was an important component of all repellency models. Initial levels of spatial repellency were also related to polarizability of the molecule and lowest unoccupied molecular orbital (LUMO) energy, whereas the equation for late spatial repellency was dependent on other electronic features, including Mulliken population and electrotopological state descriptors. The model identified for contact repellency was the best fit and most significant model in this analysis and showed a relationship with vapor pressure, Mulliken population, and total energy.

  5. Durability of two water repelents applied to granite

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    1998-06-01

    Full Text Available The durability of two water-repellents for granitic stonework was determined. Weathered and sound samples of granites widely used in building construction and restoration in Galicia (NW Spain were treated with water repellents of known efficacy, and then subjected to two artificial weathering tests: prolonged exposure to UV light, and sodium sulphate crystallization cycles. In both tests, but especially in the salt crystallization cycles, both treatments rapidly lost their water-repellency. Furthermore, the hydrophobic layer of water repellent impeded salt mobility, favouring fissuration parallel to the treated surface, which was eventually shed in the form of a plaque.

    Se presentan los resultados de la durabilidad de dos tratamientos de hidrofugación aplicados a rocas graníticas ampliamente utilizados en la construcción de edificios en Galicia (Noroeste de España. Tras la evaluación de la eficacia de dichos tratamientos, cuyos resultados se presentaron en un trabajo anterior, se someten las muestras tratadas a dos ensayos diferentes de envejecimiento acelerado: ciclos de exposición a la luz ultravioleta y ciclos de cristalización de sulfato de sodio. Los productos hidrofugantes muestran una escasa resistencia a ambos ensayos, sobre todo a los ciclos de cristalización de sulfato de sodio; esta débil durabilidad se manifiesta en una rápida pérdida de sus propiedades hidrofugantes. Así mismo, se observa que la presencia de la capa hidrófoba en la piedra funciona como una barrera frente a la movilidad de sales, lo que ocasiona el total desprendimiento de aquella y un fuerte deterioro del material rocoso.

  6. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin.

    Science.gov (United States)

    Choi, Youngmin; Choo, Hyunwook; Yun, Tae Sup; Lee, Changho; Lee, Woojin

    2016-12-02

    Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°). Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

  7. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    Directory of Open Access Journals (Sweden)

    Youngmin Choi

    2016-12-01

    Full Text Available Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°. Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

  8. A study on effects of water repellent on the performance of expanded perlite products%憎水剂对膨胀珍珠岩制品性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    郭现龙; 田英良; 孙诗兵; 陈华; 高庆

    2012-01-01

    Due to large absorbing water, expanded perlite is limited to apply in the field of building energy1-saving. In this paper, effects of water repellent on strength and water absorption of expanded perlite products are studied by selecting different kinds, concentration of absorbing water, and using different hydrophobic treatment. The results show, add composite water repellent to expanded perlite product raw materials by blending mix way can effectively reduce the water absorption rate, at the same time, hydrophobic rate can reach to 98%. This study is helpful to improve hydrophobic properties of perlite products and promote its application in building engineering.%膨胀珍珠岩因吸水率大,制约其在建筑节能领域的应用.通过选取不同种类、浓度的憎水剂,采用不同憎水处理方式,研究憎水剂对膨胀珍珠岩制品吸水率、强度等性能的影响规律.结果表明,采用掺拌方式将复合憎水剂加入到膨胀珍珠岩制品原料中,可有效降低其吸水率,同时憎水率可达98%.有利于改进珍珠岩制品的憎水性能,促进其在建筑工程中的应用.

  9. Essential oil based polymeric patch development and evaluating its repellent activity against mosquitoes.

    Science.gov (United States)

    Chattopadhyay, Pronobesh; Dhiman, Sunil; Borah, Somi; Rabha, Bipul; Chaurasia, Aashwin Kumar; Veer, Vijay

    2015-07-01

    Essential oil based insect repellents are environment friendly and provide dependable personal protection against the bites of mosquitoes and other blood-sucking insects. In the present study, optimized mixture of three essential oils was embedded into the ethylcellulose (EC) and polyvinylpyrrolidone (PVP K-30) polymers to develop essential oils based patch type mosquito repellent formulation. The developed formulation was characterized for various physico-chemical properties, oil release efficiency and essential oil-polymer interaction. Repellent activity of the formulation was evaluated against Ae. (S) albopictus mosquitoes and compared with commercially available synthetic insecticide based mosquito repellent cream Odomos(®) in the laboratory. The developed patches were 100% flat and there was no interaction between oil components and the excipients. Patches were smooth, homogenous and provided excellent mosquito repellent activity comparable to Odomos(®) under laboratory condition. Morphological and physico-chemical characterization indicated that the formulation was stable and suitable with the polymeric combination. The patch formulation did not show any inhalation toxicity in experimental Wistar rat. The repellent patches developed and evaluated currently, may provide a suitable, eco-friendly, acceptable and safe alternative to the existing synthetic repellent formulations for achieving protection against mosquitoes.

  10. Repellency of aerosol and cream products containing fennel oil to mosquitoes under laboratory and field conditions.

    Science.gov (United States)

    Kim, Soon-Il; Chang, Kyu-Sik; Yang, Young-Cheol; Kim, Byung-Seok; Ahn, Young-Joon

    2004-11-01

    The repellency of fennel (Foeniculum vulgare Miller)-containing products (5% aerosol and 8% cream) against mosquitoes was compared with those of citronella oil, geranium oil and deet, as well as three commercial repellents, Baby Keeper cream containing IR3535, MeiMei cream containing citronella and geranium oils, and Repellan S aerosol containing 19% N,N-diethyl-m-toluamide (deet) under laboratory and field conditions. In a laboratory study with female Aedes aegypti (L), fennel oil exhibited good repellency in a release-in-cage test and repellency in skin and patch tests of the oil was comparable with those of citronella and geranium oils. In paddy field tests with five human volunteers, 5% and 8% fennel oil-containing aerosol and cream produced 84% and 70% repellency, respectively, at 90 min after exposure, whereas Baby Keeper cream and MeiMei cream gave 71% and 57% repellency at 90 min after exposure, respectively, and Repellan S aerosol gave 89% repellency at 210 min. The species and ratio of mosquitoes collected were the genera Culex (44.1%), Anopheles (42.2%), Aedes (7.8%) and Armigeres (5.9%). Fennel oil-containing products could be useful for protection from humans and domestic animals from vector-borne diseases and nuisance caused by mosquitoes.

  11. From Chemistry to Behavior. Molecular Structure and Bioactivity of Repellents against Ixodes ricinus Ticks.

    Directory of Open Access Journals (Sweden)

    Simone Del Fabbro

    Full Text Available Tick-borne zoonoses are considered as emerging diseases. Tick repellents represent an effective tool for reducing the risk of tick bite and pathogens transmission. Previous work demonstrated the repellent activity of the phenylpropanoid eugenol against Ixodes ricinus; here we investigate the relationship between molecular structure and repellency in a group of substances related to that compound. We report the biological activity of 18 compounds varying for the presence/number of several moieties, including hydroxyl and methoxy groups and carbon side-chain. Each compound was tested at different doses with a bioassay designed to measure repellency against individual tick nymphs. Both vapor pressure and chemical features of the tested compounds appeared to be related to repellency. In particular, the hydroxyl and methoxy groups as well as the side-chain on the benzene ring seem to play a role. These results are discussed in light of available data on chemical perception in ticks. In the course of the study new repellent compounds were identified; the biological activity of some of them (at least as effective as the "gold standard" repellent DEET appears to be very promising from a practical point of view.

  12. Soil water repellency induced by long-term irrigation with treated sewage effluent.

    Science.gov (United States)

    Wallach, R; Ben-Arie, O; Graber, E R

    2005-01-01

    This study describes soil water repellency developed under prolonged irrigation with treated sewage effluent in a semiarid environment. Soil surface layer (0-5 cm) and soil profile (0-50 cm) transects were sampled at a high resolution at the close of the irrigation season and rainy winter season. Samples from 0- to 5-cm transects were subdivided into 1-cm slices to obtain fine scale resolution of repellency and organic matter distribution. Extreme to severe soil water repellency in the 0- to 5-cm soil surface layer persisted throughout the 2-yr study period in the effluent-irrigated Shamouti orange [Citrus sinensis (L.) Osbeck cv. Shamouti] orchard plot. Nearby Shamouti orange plots irrigated with tap water were either nonrepellent or only somewhat repellent. Repellency was very variable spatially and with depth, appearing in vertically oriented "repellency tongues." Temporal and spatial variability in repellency in the uppermost 5-cm soil surface layer was not related to seasonality, soil moisture content, or soil organic matter content. Nonuniform distribution of soil moisture and fingered flow were observed in the soil profile after both seasons, demonstrating that the repellent layer had a persistent effect on water flow in the soil profile. A lack of correlation between bulk density and volumetric water content in the soil profile demonstrates that the observed nonuniform spatial distribution of moisture results from preferential flow and not heterogeneity in soil properties. Soil water repellency can adversely affect agricultural production, cause contamination of underlying ground water resources, and result in excessive runoff and soil erosion.

  13. Study of the Wireless Remote Control Bird Repellent System%无线远程控制智能驱鸟系统研究

    Institute of Scientific and Technical Information of China (English)

    王晓坤; 魏思东; 王宏峰; 刘晓峰

    2015-01-01

    This paper analyzes the current status of military airport bird control and designs an one-to-many intelligent wireless remote control bird repellent system based on STM32F407A and nRF2401. The overall design of the system and hardware designs have been done in this paper. The system meets the requirements by laboratory testing and field testing and can realize effective bird repellent within the three dimensional airport airspace.%分析了当前军用机场鸟害防治的现状,设计了基于STM32F407A和nRF2401的驱鸟车和驱鸟器"一对多"无线远程控制智能系统,阐述了系统的整体设计和硬件设计方案.该系统可靠性好、易于扩展和更新、升级,能实现机场空域三维空间内有效驱鸟.

  14. Repellent effect of microencapsulated essential oil in lotion formulation against mosquito bites.

    Science.gov (United States)

    Misni, Norashiqin; Nor, Zurainee Mohamed; Ahmad, Rohani

    2017-01-01

    Many essential oils have been reported as natural sources of insect repellents; however, due to high volatility, they present low repellent effect. Formulation technique by using microencapsulation enables to control the volatility of essential oil and thereby extends the duration of repellency. In this study, the effectiveness of microencapsulated essential oils of Alpinia galanga, Citrus grandis and C. aurantifolia in the lotion formulations were evaluated against mosquito bites. Essential oils and N,N-Diethyl-3-methylbenzamide (DEET) were encapsulated by using interfacial pre- cipitation techniques before incorporation into lotion base to form microencapsulated (ME) formulation. The pure essential oil and DEET were also prepared into lotion base to produce non-encapsulated (NE) formulation. All the prepared formulations were assessed for their repellent activity against Culex quinquefasciatus under laboratory condition. Field evaluations also were conducted in three different study sites in Peninsular Malaysia. In addi- tion, Citriodiol® (Mosiquard®) and citronella-based repellents (KAPS®, MozAway® and BioZ Natural®) were also included for comparison. In laboratory conditions, the ME formulations of the essential oils showed no significant difference with regard to the duration of repellent effect compared to the microencapsulated DEET used at the highest con- centration (20%). It exhibited >98% repellent effect for duration of 4 h (p = 0.06). In the field conditions, these formulations demonstrated comparable repellent effect (100% for a duration of 3 h) to Citriodiol® based repellent (Mosiguard®) (p = 0.07). In both test conditions, the ME formulations of the essential oils presented longer duration of 100% repellent effect (between 1 and 2 h) compared to NE formulations. The findings of the study demonstrate that the application of the microencapsulation technique during the preparation of the formulations significantly increases the duration of the

  15. Protective efficacy of menthol propylene glycol carbonate compared to N, N-diethyl-methylbenzamide against mosquito bites in Northern Tanzania.

    Science.gov (United States)

    Kweka, Eliningaya J; Munga, Stephen; Mahande, Aneth M; Msangi, Shandala; Mazigo, Humphrey D; Adrias, Araceli Q; Matias, Jonathan R

    2012-09-05

    The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08), Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET), either as a single dose or in combination (blend), both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus. In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00  hr to 01:00  hr. A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30%) were An. gambiae s.l while 66 (2.70%) were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx. quinquefasciatus were significantly prevented from blood

  16. Protective efficacy of menthol propylene glycol carbonate compared to N, N-diethyl-methylbenzamide against mosquito bites in Northern Tanzania

    Directory of Open Access Journals (Sweden)

    Kweka Eliningaya J

    2012-09-01

    Full Text Available Abstract Background The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08, Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET, either as a single dose or in combination (blend, both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus. Methods In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00 hr to 01:00 hr. Results A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30% were An. gambiae s.l while 66 (2.70% were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx

  17. LARVICIDAL POTENTIAL AND MOSQUITO REPELLENT ACTIVITY OF CASSIA MIMOSOIDES EXTRACTS.

    Science.gov (United States)

    Alayo, M A; Femi-Oyewo, M N; Bakre, L G; Fashina, A O

    2015-07-01

    This study aims to investigate larvicidal activities of extracts of Cassia mimosoides leaves and pods as a potential agent in vector control of malaria and to evaluate repellent effect against Anopheles gambiae mosquito of the extract formulated in an aqueous cream base. Petroleum spirit, ethanol, water and dichloromethane extracts were tested against third and fourth instar Anopheles gambiae larvae. The petroleum extract was formulated in an aqueous cream base and repellency determined using N-N-diethyl-m-toluamide (DEET) as control. Phytochemical analysis showed the presence of saponins, tannins, anthraquinones, steroids, and flavonoids but absence of cardiac glycosides and alkaloids in powdered C. mimosoides. A dose related response was observed in the mortality rate of the extracts, with 2 mg/ml petroleum ether and dichloromethane extracts achieving 100 % mortality. Larvicidal activity of extracts based on LC50 values was petroleum ether > dichloromethane > ethanol > water. The formulated petroleum ether extract cream had a characteristic odor, hard and smooth texture, skin feeling of smoothness, ease of application by rubbing, easy removal using soap and water, non-irritating effect on skin and an acceptable pH value. The cream containing 2%-6% (w/w) extract and control achieved 100% repellency against mosquitoes after an exposure time of 5 minutes. There was a linear relationship between percent concentration of plant extract in the cream samples and repellent activity. These results suggest that crude extracts of C. mimosoides can be developed as eco-friendly larvicide and mosquito repellent and encourage further effort to investigate the bioactive compounds in the extracts.

  18. Bioresorbable adhesion barrier for reducing the severity of postoperative cardiac adhesions: Focus on REPEL-CV®

    Directory of Open Access Journals (Sweden)

    Martin Haensig

    2011-01-01

    Full Text Available Martin Haensig, Friedrich Wilhelm Mohr, Ardawan Julian RastanDepartment of Cardiac Surgery, Heart Center, University of Leipzig, Leipzig, GermanyAbstract: Treatment of a number of congenital heart defects often necessitates staged surgical intervention. In addition, substantial improvements in postoperative cardiac care and more liberal use of biological valve substitutes have resulted in many adult patients surviving to become potential candidates for reoperations to repair or replace valves or to undergo additional revascularization procedures. In all these scenarios, surgeons are confronted with cardiac adhesions, leading to an increased surgical risk. Thus, bioresorbable adhesion barriers had become of increasing interest because they are easy to use, and safe and effective. This review focuses on the mechanisms by which REPEL-CV® prevents adhesive processes, as well as the development, design, and materials used, and also summarizes efficacy studies, clinical data, safety, and current role in therapy.Keywords: adhesion prevention, bioresorbable copolymer, cardiac reoperation

  19. Mella (Olax zeylanica Leaves as an Eco-friendly Repellent for Storage Insect Pest Management

    Directory of Open Access Journals (Sweden)

    H. S. D. Fernando

    2013-04-01

    Full Text Available Among the cereals, rice is the most important staple food supplying energy requirements for mostof the worlds’ population. However during storage a loss of about 10-20% rice grains occurs due to storedgrain pests. Repellents are considered as the best source of protection against insect attack upon storedproducts as they have potential for the exclusion of stored product pests from grain, and therebypreventing insect feeding and oviposition on food materials. Various plant materials have been utilizedeffectively through time as safe and ecofriendly insect pest control measures due to their repellentactivity. The aim of the present study was to investigate the potential of powdered leaves and leaf extractsof Olax zeylanica as repellents against the rice weevil, Sitophilus oryzae. All the experiments were carriedout under laboratory conditions using 1-7 day old unsexed adults. Four different doses (1.0g, 3.0g, 5.0gand 7.0g.of powdered leaves were tested for fumigant repellency in a dual-choice bio-assay apparatus.Repellent action of leaf extracts was evaluated by means of an area preference test using methanol,ethanol and n- hexane as solvents. Repellent effect of powdered leaves against the adult rice weevils wasfound to be significantly high (P< 0.05 at all doses. The highest repellent effect was produced by 7.0g ofleaf powder resulting in repellency of 97%, while the lowest dose (1.0g also elicited more than 50%repellency in weevils indicating a very strong repellent action of the powdered leaves. In comparison,methanol extract of leaves produced the highest repellent effect (96% on weevils whereas n-hexaneextract elicited the lowest. Nevertheless, at higher concentrations all three extracts produced more or lesssignificantly similar repellent effect on the weevils. The findings of the present study suggest that certainactive materials of Olax zeylanica leaves have potential to act as a grain protectant and may be exploitedfor the control of

  20. Tetranychus urticae‐triggered responses promote genotype‐dependent conspecific repellence or attractiveness in citrus

    National Research Council Canada - National Science Library

    Agut, Blas; Gamir, Jordi; Jaques, Josep A; Flors, Victor

    2015-01-01

    .... In this study, we observed that the release of T. urticae herbivore‐induced plant volatiles ( HIPV s) from sour orange plants has a marked repellent effect on conspecific mites associated with the production of the terpenes...

  1. Pest repellent properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2012-01-01

    Many ant species are efficient control agents against a wide range of pest insects in many crops. They control pest insects via predation; however, ant communication is based on chemical cues which may be eavesdropped by potential prey and serve as chemical warning signals. Thus, the presence...... of ant pheromones may be sufficient to repel pest insects from ant territories. The study of ant semiochemicals is in its infancy, yet, evidence for their potential use in pest management is starting to build up. Pheromones from four of five tested ant species have been shown to deter herbivorous insect...... prey and competing ant species are also deterred by ant deposits, whereas ant symbionts may be attracted to them. Based on these promising initial findings, it seems advisable to further elucidate the signaling properties of ant pheromones and to test and develop their use in future pest management....

  2. Self-Efficacy and Interest: Experimental Studies of Optimal Incompetence.

    Science.gov (United States)

    Silvia, Paul J.

    2003-01-01

    To test the optimal incompetence hypothesis (high self-efficacy lowers task interest), 30 subjects rated interest, perceived difficulty, and confidence of success in different tasks. In study 2, 33 subjects completed a dart-game task in easy, moderate, and difficult conditions. In both, interest was a quadratic function of self-efficacy,…

  3. Repellent effects of Melaleuca alternifolia (tea tree) oil against cattle tick larvae (Rhipicephalus australis) when formulated as emulsions and in β-cyclodextrin inclusion complexes.

    Science.gov (United States)

    Yim, Wei Tsun; Bhandari, Bhesh; Jackson, Louise; James, Peter

    2016-07-30

    Rhipicephalus australis (formerly Boophilus microplus) is a one host tick responsible for major economic loss in tropical and subtropical cattle production enterprises. Control is largely dependent on the application of acaricides but resistance has developed to most currently registered chemical groups. Repellent compounds that prevent initial attachment of tick larvae offer a potential alternative to control with chemical toxicants. The repellent effects of Melaleuca alternifolia oil (TTO) emulsions and two β-cyclodextrin complex formulations, a slow release form (SR) and a modified faster release form (FR), were examined in a series of laboratory studies. Emulsions containing 4% and 5% TTO applied to cattle hair in laboratory studies completely repelled ascending tick larvae for 24h whereas 2% and 3% formulations provided 80% protection. At 48h, 5% TTO provided 78% repellency but lower concentrations repelled less than 60% of larvae. In a study conducted over 15 days, 3% TTO emulsion applied to cattle hair provided close to 100% repellency for 2 days, but then protection fell to 23% by day 15. The FR formulation gave significantly greater repellency than the emulsion and the SR formulation from day 3 until the end of the study (P<0.05), providing almost complete repellency at day 3 (99.5%), then decreasing over the period of the study to 49% repellency at day 15. Proof of concept is established for the use of appropriately designed controlled-release formulations to extend the period of repellency provided by TTO against R. australis larvae.

  4. Repellent Action of Carapa guianensis and Caesalpinia ferrea for flies species of Calliphoridae family

    Directory of Open Access Journals (Sweden)

    Ciciane Pereira Marten Fernandes

    2016-05-01

    Full Text Available ABSTRACT: Myiases occur by the infestation of fly larvae in tissues of live vertebrate animals, resulting in economic loss. Phytotherapy is considered an important alternative in the control of insects, which may reduce the economic impacts . Carapa guianensis is a plant that has been studied as a repellent against mosquitoes and Caesalpinia ferrea is reported in tropical climates, and there are few studies about its repellent action. The present study was designed to evaluate the repellent action of s C. guianensis and C. ferrea plants on flies species of the Calliphoridae family. W.O.T. traps containing deteriorated bovine liver and herbs cream of at concentrations of 20 and 50% were used to catch the flies. It was reported that the creams containing C. ferrea at concentrations of 20 and 50% and C. guianensis at the concentration of 50% have repellent effect against species of Calliphoridae family.

  5. Field evaluation of herbal mosquito repellents.

    Science.gov (United States)

    Das, N G; Nath, D R; Baruah, I; Talukdar, P K; Das, S C

    1999-12-01

    Repellent properties of Zanthoxylum armatum DC. Syn. Z. alatum Roxb. (Timur), Curcuma aromatica (Jungli haldi) and Azadirachta indica (Neem) oils were evaluated against mosquitoes in mustard (Brassica sp.) and coconut (Cocos sp.) oil base and compared with synthetic repellent. Dimethyl phthalate (DMP) as standard. Timur and jungli haldi afforded better protection in the both the base at all the concentrations. Tepellents in mustard oil gave longer protection time than those in coconut oil. At 0.57 mg/cm2 concentration timur oil gave significantly higher protection both in mustard (445 min) as well as coconut oil (404 min) than the other repellents and DMP.

  6. Effects of kaolinite and drying temperature on the persistence of soil water repellency induced by humic acids

    NARCIS (Netherlands)

    Lichner, L.; Babejová, N.; Dekker, L.W.

    2002-01-01

    The effects of kaolinite additions and drying temperature on the persistence of soil water repellency, induced by humic acids from peat, were assessed in this study. It was found that additions of 5 and 10% kaolinite (referred to as the most effective material in combating the water repellency) did

  7. Wash resistance and repellent properties of Africa University mosquito blankets against mosquitoes

    Directory of Open Access Journals (Sweden)

    N. Lukwa

    2013-04-01

    Full Text Available The effect of permethrin-treated Africa University (AU mosquito blankets on susceptible female Anopheles gambiae sensu lato mosquitoes was studied under laboratory conditions at Africa University Campus in Mutare, Zimbabwe. Wash resistance (ability to retain an effective dose that kills ≥80% of mosquitoes after a number of washes and repellence (ability to prevent ≥80% of mosquito bites properties were studied. The AU blankets were wash resistant when 100% mortality was recorded up to 20 washes, declining to 90% after 25 washes. Untreated AU blankets did not cause any mortality on mosquitoes. However, mosquito repellence was 96%, 94%, 97.9%, 87%, 85% and 80.7% for treated AU blankets washed 0, 5, 10, 15, 20 and 25 times, respectively. Mosquito repellence was consistently above 80% from 0-25 washes. In conclusion, AU blankets washed 25 times were effective in repelling and killing An. gambiae sl mosquitoes under laboratory conditions.

  8. Lime-based repair mortars with water-repellent admixtures: laboratory durability assessment

    OpenAIRE

    Nunes, C.; Slížková, Z. (Zuzana)

    2015-01-01

    Conservation of architectural structures using lime binders is currently an important research topic aiming compatibility, durability and sustainability. In this study, lime (L) and lime-metakaolin (LM) mortars were prepared with the addition of water-repellent admixtures: linseed oil, stand oil and a silane based water-repellent. Experimental results demonstrate that oil imparts higher hydrophobicity to both L and LM mixtures. Durability was assessed through freeze-thaw and NaCl crystal...

  9. Repellent and Anti-quorum Sensing Activity of Six Aromatic Plants Occurring in Colombia.

    Science.gov (United States)

    Cervantes-Ceballos, Leonor; Caballero-Gallardo, Karina; Olivero-Verbel, Jesus

    2015-10-01

    Essential oils (EOs) are widely used as biopesticides and to control bacterial infections. This study describes the ability of six EOs isolated from plants cultivated in Colombia to perform as repellents against Ulomoides dermestoides and as quorum sensing (QS) inhibitors. EOs from Aloysia triphylla, Cymbopogon nardus, Lippia origanoides, Hyptis suaveolens, Swinglea glutinosa and Eucalyptus globulus were repellents classified as Class IV, IV, IV, III, II, and II, respectively, whereas the commercial repellent IR3535 only reached Class II after 2 h exposure. All EOs presented small, but significant inhibitory properties against the QS system in Escherichia coli (pJBA132) at 25 μg/mL after 4 h exposure. These data suggest evaluated EOs from Colombia are sustainable, promising new sources of natural repellents and could be important as anti-quorum sensing molecules.

  10. Repellent activity of constituents identified in Foeniculum vulgare fruit against Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Kim, Do-Hyoung; Kim, Soon-Il; Chang, Kyu-Sik; Ahn, Young-Joon

    2002-11-20

    The repellent activity of materials derived from the methanol extract of fruits from Foeniculum vulgareagainst hungry Aedes aegypti females was examined using skin and patch tests and compared with that of the commercial N,N-diethyl-m-toluamide (deet) and (Z)-9-octadecenoic acid. The biologically active constituents of the Foeniculum fruits were characterized as (+)-fenchone and (E)-9-octadecenoic acid by spectroscopic analyses. Responses varied according to compound, dose, and exposure time. In a skin test with female mosquitoes, at a dose of 0.4 mg/cm(2), (+)-fenchone and (Z)-9-octadecenoic acid exhibited moderate repellent activity at 30 min after treatment, whereas deet provided >1 h of protection against adult mosquitoes at 0.2 mg/cm(2). (Z)-9-Octadecenoic acid was a more potent repellent agent than (E)-9-octadecenoic acid. (+)-Fenchone and (E)-9-octadecenoic acid merit further study as potential mosquito repellent agents or as lead compounds.

  11. Laboratory evaluation of aromatic essential oils from thirteen plant species as candidate repellents against Leptotrombidium chiggers (Acari: Trombiculidae), the vector of scrub typhus.

    Science.gov (United States)

    Eamsobhana, Praphathip; Yoolek, Adisak; Kongkaew, Wittaya; Lerdthusnee, Kriangkrai; Khlaimanee, Nittaya; Parsartvit, Anchana; Malainual, Nat; Yong, Hoi-Sen

    2009-03-01

    Scrub typhus, a rickettsial disease transmitted by several species of Leptotrombidium chiggers (larvae), is endemic in many areas of Asia. The disease is best prevented by the use of personal protective measures, including repellents. In this study commercially produced aromatic, essential oils of 13 plant species and ethanol (control) were tested in the laboratory for repellency against host-seeking chiggers of Leptotrombidium imphalum Vercammen-Grandjean and Langston (Acari: Trombiculidae). A rapid, simple and economic in vitro test method was used by exposing the chigger for up to 5 min. Repellency was based on relative percentages of chiggers attracted to test and control substances. Four of the 13 essential oils showed promise as effective repellent against L. imphalum chiggers. Syzygium aromaticum (clove) oil exhibited 100% repellency at 5% concentration (dilution with absolute ethanol), whereas Melaleuca alternifolia (tea tree) oil exhibited 100% repellency at 40% concentration. Undiluted oils of Zingiber cassamunar (plai) and Eucalyptus globules (blue gum) exhibited 100% repellency. Of the remaining nine essential oils, only 100% Pelargonium graveolens (geranium) exhibited >50% repellency (viz. 57%). Styrax torkinensis (benzoin) oil did not exhibit any repellency. These findings show that several aromatic, essential oils of plants may be useful as chigger repellent for the prevention of scrub typhus. Syzygium aromaticum oil may be safer and more economical to prevent chigger attacks than commercially available synthetic chemicals, such as DEET that may have harmful side effects.

  12. Liquid repellency by a moving plate

    Science.gov (United States)

    Bouillant, Ambre; Anais Gauthier Team; David Quere Team; Christophe Clanet Team

    2016-11-01

    Moving solids can repel impacting drops, owing to their motion. Provided the solid velocity is larger than a threshold value, air entrained at the vicinity of the moving plate prevents the drop from wetting, and makes it bounce. In addition, the rebound is oblique, which enhances the evacuation of liquid. We discuss experiments and models on this theme, and extend them to case of small droplets (such as formed in a spray) found to be even more efficiently repelled by the moving plate.

  13. Repellent and mosquitocidal effects of leaf extracts of Clausena anisata against the Aedes aegypti mosquito (Diptera: Culicidae).

    Science.gov (United States)

    Mukandiwa, Lillian; Eloff, Jacobus Nicolaas; Naidoo, Vinny

    2016-06-01

    Mosquitoes are rapidly developing resistance to insecticides that millions of people relied on to protect themselves from the diseases they carry, thereby creating a need to develop new insecticides. Clausena anisata is used traditionally as an insect repellent by various communities in Africa and Asia. For this study, the repellency and adulticidal activities of leaf extracts and compounds isolated from this plant species were evaluated against the yellow fever mosquito, Aedes aegypti. In the topical application assays, using total bites as an indicator, repellency was dose dependent, with the acetone crude extract (15 %) having 93 % repellence and the hexane fraction (7.5 %) 67 % repellence after 3 h. Fractionation resulted in a loss of total repellence. As mosquito-net treating agents, the acetone and hexane extracts of C. anisata, both at 15 %, had average repellences of 46.89 ± 2.95 and 50.13 ± 2.02 %, respectively, 3 h after exposure. The C. anisata acetone extract and its hexane fraction caused mosquito knockdown and eventually death when nebulised into the testing chamber, with an EC50 of 78.9 mg/ml (7.89 %) and 71.6 mg/ml (7.16 %) in the first 15 min after spraying. C. anisata leaf extracts have potential to be included in protection products against mosquitoes due to the repellent and cidal compounds contained therein.

  14. Octanoic acid confers to royal jelly varroa-repellent properties

    Science.gov (United States)

    Nazzi, Francesco; Bortolomeazzi, Renzo; Della Vedova, Giorgio; Del Piccolo, Fabio; Annoscia, Desiderato; Milani, Norberto

    2009-02-01

    The mite Varroa destructor Anderson & Trueman is a parasite of the honeybee Apis mellifera L. and represents a major threat for apiculture in the Western world. Reproduction takes place only inside bee brood cells that are invaded just before sealing; drone cells are preferred over worker cells, whereas queen cells are not normally invaded. Lower incidence of mites in queen cells is at least partly due to the deterrent activity of royal jelly. In this study, the repellent properties of royal jelly were investigated using a lab bioassay. Chemical analysis showed that octanoic acid is a major volatile component of royal jelly; by contrast, the concentration is much lower in drone and worker larval food. Bioassays, carried out under lab conditions, demonstrated that octanoic acid is repellent to the mite. Field studies in bee colonies confirmed that the compound may interfere with the process of cell invasion by the mite.

  15. Phoenix dactylifera L. spathe essential oil: chemical composition and repellent activity against the yellow fever mosquito.

    Science.gov (United States)

    Demirci, Betül; Tsikolia, Maia; Bernier, Ulrich R; Agramonte, Natasha M; Alqasoumi, Saleh I; Al-Yahya, Mohammed A; Al-Rehaily, Adnan J; Yusufoglu, Hasan S; Demirci, Fatih; Başer, K Hüsnü Can; Khan, Ikhlas A; Tabanca, Nurhayat

    2013-12-01

    Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dactylifera was obtained by hydrodistillation from the spathe, a specialized leaf structure that surrounds the pollinating organs of the palm. The oil was subsequently analyzed by GC-FID and GC-MS. The oil showed promising repellent activity against yellow fever mosquito - Aedes aegypti. Sixteen components were characterized, constituting 99% of the oil. The main components were 3,4-dimethoxytoluene (73.5%), 2,4-dimethoxytoluene (9.5%), β-caryophyllene (5.5%), p-cresyl methyl ether (3.8%), and caryophyllene oxide (2.4%). The minimum effective dosage (MED) for repellency for the P. dactylifera oil was 0.051mg/cm(2), which had moderately lower potency compared to reference standard N,N-diethyl-3-methylbenzamide, DEET (0.018mg/cm(2)) in the "cloth patch assay". The five major compounds were individually assayed for repellency to determine to what extent each is responsible for repellency from the oil. 3,4-Dimethoxytoluene and 2,4-dimethoxytoluene showed the best repellent activity with the same MED value of 0.063mg/cm(2), respectively. The results indicate that these two constituents which comprise a large proportion of the P. dactylifera oil (83%) are likely responsible for the observed repellent activity. In this aspect, the P. dactylifera spathe oil is a sustainable, promising new source of natural repellents.

  16. Impact of water content and decomposition stage on the soil water repellency of peat soils

    Science.gov (United States)

    Dettmann, Ullrich; Sokolowsky, Liv; Piayda, Arndt; Tiemeyer, Bärbel; Bachmann, Jörg

    2017-04-01

    Soil water repellency is widely reported for all kinds of soils and mainly caused by hydrophobic organic compounds. It has a substantial influence on soil hydraulic processes such as water infiltration, preferential flow paths and evaporation and therefore on hydrological processes in general. The severity of soil water repellency strongly depends on the soil water content and the amount of soil organic carbon. Although peat soils are characterized by high soil organic carbon contents, studies about peat soils are rare and mostly available for horticultural substrates. Here, we present soil water repellency measurements for peat soils with varying porosities, bulk densities and stages of decomposition. The peat soils were sampled at two different sites in a bog complex. The sites have been drained for 1 and 100 years. Samples were taken from each soil layer and, additionally, in a vertical resolution of 0.03 m. To determine the soil water contents at which the peat becomes water repellent, we applied the commonly used water drop penetration time test on progressively dewatered samples. In order to identify the influence of the decomposition stage as determined by the depth within the soil profile and duration of drainage, the potential soil water repellency was measured at air-dried sieved samples by the sessile drop method. First results show that the soil water repellency of peat soils is strongly dependent on the soil water content. For air-dried peat samples, the influence of different decomposition stages of the bog peat is negligible. All air-dried samples are extremely water repellent with contact angles > 130°. However, comparing the results with the soil organic matter content shows a slightly tendency of increasing soil water repellency with increasing soil organic matter contents.

  17. Synergistic insecticidal and repellent effects of combined pyrethroid and repellent-impregnated bed nets using a novel long-lasting polymer-coating multi-layer technique.

    Science.gov (United States)

    Faulde, Michael K; Nehring, Oliver

    2012-08-01

    New and improved strategies for malaria control and prevention are urgently needed. As a contribution to an optimized personal protection strategy, a novel long-lasting insecticide and repellent-treated net (LLIRN) has been designed by binding combinations of permethrin plus N,N-diethyl-m-toluamide (DEET), or insect repellent 3535 (IR3535), and etofenprox plus DEET, onto fibres of bed net fabric employing a new multi-layer polymer-coating technique. Protective repellent efficacy, toxicological effectiveness and residual activity of 12 LLIRN types have been evaluated by laboratory testing against adult Aedes aegypti. The novel multi-layer LLIRN design allowed simultaneous embedding at concentrations up to 5,930 mg/m(2) for DEET, 3,408 mg/m(2) for IR3535, 2,296 mg/m(2) for permethrin and 2,349 mg/m(2) for etofenprox, respectively. IR3535 layers prevented co-binding of additional pyrethroid-containing polymer layers, thus making pyrethroids plus DEET LLIRNs an ideal combination. All LLIRNs revealed synergistic insecticidal effects which, when measured against concentration controls of the isolated compounds, were significant in all LLIRN types designed. DEET in DEET plus permethrin LLIRNs significantly (p repellency of DEET or IR3535 on LLIRNs. Vice versa, DEET and IR3535 increased spatial and excitatory repellency and reduced landing and probing frequency on LLIRNs resulting in strongly enhanced biting protection, even at low concentrations. One hundred percent biting and probing protection of stored LLIRNs was preserved for 83 weeks with the 5,930 mg/m(2) DEET and 2,139 mg/m(2) etofenprox LLIRN, for 72 weeks with the 5,002 mg/m(2) DEET and 2,349 mg/m(2) etofenprox LLIRN, for 63 weeks with the 3,590 mg/m(2) DEET and 1,208 mg/m(2) permethrin LLRN, and for 61 weeks with the 4,711 mg/m(2) DEET and 702 mg/m(2) etofenprox LLIRN. Because 100 % bite protection with up to 75 % quicker contact toxicity of pyrethroids were documented, synergistic toxicological and repellent

  18. The influence of clay type on reduction of water repellency by applied clays: a review of some West Australian work

    Science.gov (United States)

    McKissock, I.; Walker, E. L.; Gilkes, R. J.; Carter, D. J.

    2000-05-01

    In Western Australia water repellency mostly occurs in soils with sandy texture; the severity of water repellency is influenced by very small changes in clay content. Additions of 1-2% clay can prevent water repellency and for some time clay amendments have been used by farmers to overcome water repellency. The aim of this study was to assess the effectiveness of clays in ameliorating water repellency. Clays were assessed for effectiveness in reducing water repellency by mixing with water repellent sands and measuring water drop penetration time (WDPT) on the resultant mixtures. WDPT was measured on the initial mixtures, a wetting and drying cycle was imposed and WDPT measured again. Two sets of clays were assessed: four simple clays containing kaolinite (2) or smectite (2) group minerals and a group of clayey subsoil materials which had been collected by farmers. For the simple clays, clay mineral type was the most significant factor in determining response. Kaolin was much more effective than smectite. Imposition of a wetting and drying cycle greatly reduced water repellency. The dominant exchangeable cation of the clays (sodium or calcium) had little effect on the ability of the clays to reduce water repellency. The factor that was most predictive of the effectiveness of clayey subsoils materials in reducing water repellency was texture: clay content ( r2=0.18) or clay+silt content ( r2=0.23). These properties were more predictive of water repellency values after the wetting and drying cycle treatment ( r2=0.36, r2=0.44). The proportion of the clay fraction that consisted of kaolinite was next most predictive in determining effectiveness which is again indicative of kaolin group minerals being more effective than smectite group minerals. The exchangeable sodium percentage and clay dispersibility had no systematic effect on the ability of these clays to reduce water repellency. These results provide a basis for developing a practical field procedure to enable

  19. Repellent activity of plant-derived compounds against Amblyomma cajennense (Acari: Ixodidae) nymphs.

    Science.gov (United States)

    Soares, Sara Fernandes; Borges, Lígia Miranda Ferreira; de Sousa Braga, Raquel; Ferreira, Lorena Lopes; Louly, Carla Cristina Braz; Tresvenzol, Leonice Manrique Faustino; de Paula, José Realino; Ferri, Pedro Henrique

    2010-01-20

    Repellence responses of Amblyomma cajennense nymphs to callicarpenal, intermedeol, Hyptis suaveolens essential oil, extract of Melia azedarach, Cymbopogon nardus, Spiranthera odoratissima, Chenopodium ambrosioides, Ageratum conyzoides, Mentha pulegium, Ruta graveolens, and Memora nodosa were studied. Among these the extract of C. nardus stood out because of the long-lasting repellence, maintaining, in the highest concentration, 35h of protection against 90% of the nymphs. The essential oil of H. suaveolens and the extracts of C. ambrosioides and A. conyzoides showed good repellence index (66%) when applied in high concentrations. However, greater protection could be obtained at higher concentrations but with a shorter repellence time. Callicarpenal, intermedeol, extract of M. Pulegium, and M. nodosa leaves showed moderate repellence in high concentrations. Extracts from M. azedarach, R. graveolens, S. odoratissima, and M. nodosa roots showed little or no repellent effect. These results show that some plant extracts may represent a promising alternative in the control of infestations by A. cajennense. Copyright 2009 Elsevier B.V. All rights reserved.

  20. Nepetalactones from essential oil of Nepeta cataria represent a stable fly feeding and oviposition repellent.

    Science.gov (United States)

    Zhu, J J; Berkebile, D R; Dunlap, C A; Zhang, A; Boxler, D; Tangtrakulwanich, K; Behle, R W; Baxendale, F; Brewer, G

    2012-06-01

    The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most serious pests to livestock. It feeds mainly on cattle and causes significant economic losses in the cattle industry. Standard stable fly control involving insecticides and sanitation is usually costly and often has limited effectiveness. As we continue to evaluate and develop safer fly control strategies, the present study reports on the effectiveness of catnip (Nepeta cataria L.) oil and its constituent compounds, nepetalactones, as stable fly repellents. The essential oil of catnip reduced the feeding of stable flies by >96% in an in vitro bioassay system, compared with other sesquiterpene-rich plant oils (e.g. amyris and sandalwood). Catnip oil demonstrated strong repellency against stable flies relative to other chemicals for repelling biting insects, including isolongifolenone, 2-methylpiperidinyl-3-cyclohexen-1-carboxamide and (1S,2'S)-2-methylpiperidinyl-3-cyclohexen-1-carboxamide. The repellency against stable flies of the most commonly used mosquito repellent, DEET, was relatively low. In field trials, two formulations of catnip oil provided >95% protection and were effective for up to 6 h when tested on cattle. Catnip oil also acted as a strong oviposition repellent and reduced gravid stable fly oviposition by 98%. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

  1. Monoterpenes from thyme (Thymus vulgaris) as potential mosquito repellents.

    Science.gov (United States)

    Park, Byeoung-Soo; Choi, Won-Sik; Kim, Jeong-Han; Kim, Kap-Ho; Lee, Sung-Eun

    2005-03-01

    Five monoterpenes (carvacrol, p-cymene, linalool, alpha-terpinene, and thymol) derived from the essential oil of thyme (Thymus vulgaris) were examined for their repellency against the mosquito Culex pipiens pallens. All 5 monoterpenes effectively repelled mosquitoes based on a human forearm bioassay. Alpha-terpinene and carvacrol showed significantly greater repellency than a commercial formulation, N,N-diethyl-m-methylbenzamide (deet), whereas thymol showed similar repellency to that of deet. The duration of repellency after application for all these monoterpenes was equal to or higher than that of deet. These findings indicate that a spray-type solution containing 2% alpha-terpinene may serve as an alternative mosquito repellent.

  2. Spatial Patterns of Post-Fire Soil Water Repellency in Rangelands

    Science.gov (United States)

    Nelson, N. A.; Pierce, J. L.

    2006-12-01

    Water repellent soils are naturally occurring but can be created or enhanced by wildfires. Post-fire runoff and the occurrence of fire-related floods and debris flows are related to the extent and continuity of water repellent soils. While many studies have positively correlated post-fire soil water repellency with burn severity and ash thickness in forested and chaparral environments, few studies have examined fire-related water repellency in sage-bitterbrush rangelands (but see Pierson et al., 2001). Rangelands, which comprise 40% of the landmass of the United States and nearly 80% of the lands of the western U.S., burn frequently during the summer with burn areas that often exceed 200 km2. The most commonly used method to measure the extent and severity of post-fire soil water repellency is the water drop penetration test (WDPT): other tests include the molarity of ethanol test, infiltration measured with a minidisk infiltrometer, and patterns of water infiltration measured with blue dye. Unlike tests that measure time until infiltration, the blue dye test provides a means of measuring the spatial extent of water repellent soils as well as area quantification of water saturation and locations of subsurface flowpaths. In early July, 2006, fires burned approximately 1.6 km2 of sagebrush and bitterbrush-dominated rangelands in foothills near Boise, Idaho. Initial studies in August 2006 using both water drop penetration time and the blue dye test show that soil water repellency is highly variable in both extent and severity, and that repellency varies with proximity to burned sage or bitterbrush coppice sites. Out of sixty sample sites, slight soil water repellency occurred outside of coppice boundaries on three occasions, each time in an area with grass and within 1 m of a coppice. Not all coppices exhibited soil water repellency, and only 23% of sites within coppice boundaries exhibited moderate to strong water repellency, as measured by WDPT. Use of the blue dye

  3. Soil water repellency in long term drought and warming experiments

    Science.gov (United States)

    Urbanek, Emilia; Emmett, Bridget; Tietema, Albert; Robinson, David

    2017-04-01

    Increased global temperatures, altered rainfall patterns and frequently occurring extreme climatic events are already observed globally as a result of the climatic changes and further increases are predicted by the climatic models. Extreme weather events such as prolonged dry spells and heat waves can significantly affect soil ecosystem functions mainly due to decrease in soil moisture. Several studies suggested an increase in soil water repellency severity and spread as a consequence of the warming and drought, however, such understanding is based on the laboratory experimentations with soil treated as a 'black box'. In this study we tested the hypothesis of increased severity of soil water repellency subjected to drought and warming under field conditions. Occurrence and severity of soil water repellency was tested in soils subjected to a long-term (10 years) climatic simulation at two upland heathland sites in Oldebroek (Netherlands) and in Clocaenog (UK)[1]. Soil plots with similar vegetation were subjected to repeated drought and warming, compared with the control plots. Drought effect was created by a rainfall exclusion using an automatic self-retracting waterproof curtains while the warming effect was made by using a self-retracting curtains reflecting infrared radiation overnight. The results available to date provide a strong indication that climatic conditions do affect the development of SWR.

  4. Formation of Soil Water Repellency by Laboratory Burning and Its Effect on Soil Evaporation

    Science.gov (United States)

    Ahn, Sujung; Im, Sangjun

    2010-05-01

    Fire-induced soil water repellency can vary with burning conditions, and may lead to significant changes in soil hydraulic properties. However, isolation of the effects of soil water repellency from other factors is difficult, particularly under field conditions. This study was conducted to (i) investigate the effects of burning using different plant leaf materials and (ii) of different burning conditions on the formation of soil water repellency, and (iii) isolate the effects of the resulting soil water repellency on soil evaporation from other factors. Burning treatments were performed on the surface of homogeneous fully wettable sand soil contained in a steel frame (60 x 60 cm; 40 cm depth). As controls a sample without a heat treatment, and a heated sample without fuel, were also used. Ignition and heat treatments were carried out with a gas torch. For comparing the effects of different burning conditions, fuel types included oven-dried pine needles (fresh needles of Pinus densiflora), pine needle litter (litter on a coniferous forest floor, P. densiflora + P. rigida), and broad-leaf litter (Quercus mongolica + Q. aliena + Prunus serrulata var. spontanea + other species); fuel loads were 200 g, 300 g, and 500 g; and heating duration was 40 s, 90 s and 180 s. The heating duration was adjusted to control the temperature, based on previous experiments. The temperature was measured continuously at 3-second intervals and logged with two thermometers. After burning, undisturbed soil columns were sampled for subsequent experiments. Water Drop Penetration Time (WDPT) test was performed at every 1 mm depth of the soil columns to measure the severity of soil water repellency and its vertical extent. Soil water repellency was detected following all treatments. As the duration of heating increased, the thickness of the water repellent layer increased, whilst the severity of soil water repellency decreased. As regards fuel amount, the most severe soil water repellency was

  5. Water repellency in hydrophobic nanocapsules--molecular view on dewetting.

    Science.gov (United States)

    Müller, Achim; Garai, Somenath; Schäffer, Christian; Merca, Alice; Bögge, Hartmut; Al-Karawi, Ahmed Jasim M; Prasad, Thazhe Kootteri

    2014-05-26

    The hydrophobic effect plays a major role in a variety of important phenomena in chemistry, materials science and biology, for instance in protein folding and protein-ligand interactions. Studies--performed within cavities of the unique metal oxide based porous capsules of the type {(pentagon)12(linker)30}≡{(W)W5}12{Mo2(ligand)}30 with different acetate/water ligand ratios--have provided unprecedented results revealing segregation/repellency of the encapsulated "water" from the internal hydrophobic ligand walls of the capsules, while the disordered water molecules, interacting strongly with each other via hydrogen bonding, form in all investigated cases the same type of spherical shell. The present results can be (formally) compared--but only regarding the repellency effect--with the amazing "action" of the (super)hydrophobic Lotus (Nelumbo) leaves, which are self-cleaning based on water repellency resulting in the formation of water droplets picking up dirt. The present results were obtained by constructing deliberately suitable hydrophobic interiors within the mentioned capsules.

  6. Paromomycin-loaded albumin microspheres: efficacy and stability studies.

    Science.gov (United States)

    Khan, Wahid; Kumar, Rajendra; Singh, Sukhvinder; Arora, Sunil Kumar; Kumar, Neeraj

    2013-06-01

    In the present work, paromomycin-loaded albumin microspheres (PM-MS) have been formulated for passive targeting of paromomycin (PM) to macrophages, for the treatment of visceral leishmaniasis (VL). PM-MS were prepared by spray-drying method with a mean particle size of ≈ 3 µm. Thermal and chemical cross-linking methods were used for controlling drug release from the prepared microspheres (MS). PM-MS were then tested for efficacy and stability studies. In efficacy study, in vitro promastigote assay was carried out to assess the susceptibility of promastigote to PM in the concentration range of 5.0-150 µg/ml; cytotoxicity assay was performed to determine possible toxicity of PM for the host cells (peritoneal macrophages) and intracellular amastigote assay was carried out to determine the efficacy of free PM (PM solution) and encapsulated PM (PM-MS). Results obtained indicated a significant increase in efficacy of PM-MS in comparison to PM solution at equivalent concentration. Subsequently, stability studies of prepared formulation was carried out at various temperature and humidity conditions, these studies provided stability of formulation at all tested conditions including accelerated conditions. Thus, it can be concluded that present work provides an optimized formulation with stability and enhanced efficacy.

  7. Insect Repellents: Protect Your Child from Insect Bites

    Science.gov (United States)

    ... Español Text Size Email Print Share Choosing an Insect Repellent for Your Child Page Content Mosquitoes, biting ... sunscreen needs to be reapplied often. Reactions to Insect Repellents If you suspect that your child is ...

  8. Repellence and toxicity of Schinus molle extracts on Blattella germanica.

    Science.gov (United States)

    Ferrero, A A; Chopa, C Sánchez; González, J O Werdin; Alzogaray, R A

    2007-06-01

    The biological activities of ethanol and petroleum ether extracts from leaves and fruits of Schinus molle against adults of Blattella germanica were examined by repellence test and topical application. All extracts produced significant repellent effect and mortality.

  9. Hyperspectral Remote Sensing to Detect Water Repellent Soil Conditions after Forest Fires

    Science.gov (United States)

    Lewis, S. A.; Robichaud, P. R.; Wu, J. Q.

    2002-12-01

    The burning of organic surface litter during forest fires often results in a water repellent soil layer at or near the soil surface. Organic matter is volatilized and a significant fraction moves into the upper soil layers (top 5 cm). Upon cooling, soil particles are coated with hydrophobic organic substances and the soil displays drastically reduced infiltration capabilities. The degree of water repellency is related to the amount of organic material on the surface prior to the fire, and the duration and temperature of the burn. Carbon compounds that are indicative of burned organic matter have been identified spectrally in soils under laboratory conditions. The 1000-2500 nm (near through short wave infrared) range is the span of the electromagnetic spectrum exhibiting significant adsorption for many organic compounds. Since burning alters surface organic matter and it is possible to detect such a change spectrally, a hyperspectral sensor should be able to provide information ultimately relating the change in organic matter to soil water repellency. This study aims to use a hyperspectral sensor to determine the degree of water repellency of surface soil in three burn classifications (low, moderate, and high) after a forest fire. One hundred eighty plots (sixty per burn class) were selected within the Hayman fire perimeter in southern Colorado in July 2002. A hand-held hyperspectral sensor was used to measure soil reflectance at several plots within each burn classification. An aerially- mounted hyperspectral sensor was also flown over the fire site. Twelve flight lines were flown to ensure contiguous coverage of the entire fire. The on-site ground truthing included both the Water Drop Penetration Time (WDPT) test and an infiltrometer test, with the former being a traditional method and the latter a new approach for testing water repellency. Both methods correlate the time to the start of infiltration with the degree of soil water repellency. The measured soil

  10. The hydrology of water repellent soils

    Science.gov (United States)

    Shillito, R.; Berli, M.; Ghezzehei, T. A.; Moore, H. K.

    2016-12-01

    The occurrence of wildfire throughout the western U.S. is expected to increase. So, too, will flooding and erosion associated with the aftereffects of the fires. Soil water repellency (hydrophobicity) has frequently been observed after fires and is believed to increase the post-fire runoff potential, although current runoff models cannot directly account for this effect. Many physically-based runoff models incorporate an infiltration reduction factor or manipulate the soil hydraulic conductivity parameter to account for water-repellent soils in runoff generation. Beginning with fundamental principles, we developed a methodology to physically account for soil water repellency and directly account for it in the Kineros2 runoff and erosion model.

  11. Experimental Investigation of Evaporation and Drainage in Wettable and Water-Repellent Sands

    Directory of Open Access Journals (Sweden)

    Dae Hyun Kim

    2015-05-01

    Full Text Available This study presents experimental results on evaporation and drainage in both wettable and water-repellent sands whose surface wettability was artificially modified by silanization. The 2D optical and 3D X-ray computed tomographic imaging was performed during evaporation and the water retention during cyclic drainage and infiltration was measured to assess effects of wettability and initial wetting conditions. The evaporation gradually induces its front at the early stage advance regardless of the wettability and sand types, while its rate becomes higher in water-repellent Ottawa sand than the wettable one. Jumunjin sand which has a smaller particle size and irregular particle shape than Ottawa sand exhibits a similar evaporation rate independent of wettability. Water-repellent sand can facilitate the evaporation when both wettable and water-repellent sands are naturally in contact with each other. The 3D X-ray imaging reveals that the hydraulically connected water films in wettable sands facilitate the propagation of the evaporation front into the soil such that the drying front deeply advances into the soil. For cyclic drainage-infiltration testing, the evolution of water retention is similar in both wettable and water-repellent sands when both are initially wet. However, when conditions are initially dry, water-repellent sands exhibit low residual saturation values. The experimental observations made from this study propose that the surface wettability may not be a sole factor while the degree of water-repellency, type of sands, and initial wetting condition are predominant when assessing evaporation and drainage behaviors.

  12. Organic compounds of different extractability in total solvent extracts from soils of contrasting water repellency

    Science.gov (United States)

    Atanassova, Irena; Doerr, Stefan H.

    2010-05-01

    Previous studies examining organic compounds that may cause water-repellent behaviour of soils have typically focussed on analysing only the lipophilic fraction of extracted material. This study aimed to provide a more comprehensive examination by applying single- and sequential-accelerated solvent extraction (ASE), separation and analysis by GC/MS of the total solvent extracts of three soils taken from under eucalypt vegetation with different levels of water repellency. Water repellency increased in all the soils after extraction with DCM:MeOH (95:5), but was eliminated with iso-propanol/ammonia (95:5). Quantities of major lipid compound classes varied between solvents and soils. Iso-propanol/ammonia (95:5) solvent released saccharides, glycerol, aromatic acids and other polar organic compounds, which were more abundant in fractionated extracts from the single extraction and the third step sequential ASE extraction, than in the extracts from the DCM:MeOH ASE solvent. Dominant compounds extracted from all soils were long-chain alkanols (>C22), palmitic acid, C29 alkane, β-sitosterol, terpenes, terpenoids and other polar compounds. The soil with smallest repellency lacked >C18 fatty acids and had smallest concentrations of alkanols (C26, C28 and C30) and alkanes (C29, C31), but a greater abundance of more complex polar compounds than the more repellent soils. We therefore speculate that the above compounds play an important role in determining the water repellency of the soils tested. The results suggest that one-stage and sequential ASE extractions with iso-propanol:ammonia and subsequent fractionation of extracts are a useful approach in providing a comprehensive assessment of the potential compounds involved in causing soil water repellency.

  13. Soft, elastic, water-repellent materials

    Science.gov (United States)

    Coux, Martin; Clanet, Christophe; Quéré, David

    2017-06-01

    Small hydrophobic textures at solid surfaces provide water repellency, a situation whose detailed properties critically depend on the geometry of textures. Depending on their size, density, and shape, water slip, rain repellency, or antifogging can be achieved. Here, we discuss how the use of soft, elastic materials allows us to tune reversibly the texture density by stretching or relaxing the materials, which is found to impact water adhesion and rebounds. In addition, solid deformations can also be exploited to largely vary the shape of Wenzel drops, a consequence of the strong pinning of water in this state.

  14. Evaluation of DEET and eight essential oils for repellency against nymphs of the lone star tick, Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Meng, Hao; Li, Andrew Y; Costa Junior, Livio M; Castro-Arellano, Ivan; Liu, Jingze

    2016-02-01

    DEET and Eight commercially available essential oils (oregano, clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint) were evaluated for repellency against host-seeking nymphs of the lone star tick, Amblyomma americanum. Concentration-repellency response was established using the vertical paper bioassay technique for each essential oil and compared with that of N,N-diethyl-3-methyl benzamide (DEET), a standard repellent compound present in many commercial repellent formulations. The effective concentration of DEET that repels 50% of ticks (EC50) was estimated at 0.02 mg/cm(2), while EC50s of the essential oils fall between 0.113 and 0.297 mg/cm(2). Based on EC50 estimates, oregano essential oil was the most effective among all essential oils tested, followed by clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint oils. None of the tested essential oils demonstrated a level of tick repellency found with DEET. Results from this study illustrated the challenge in search for more effective natural tick repellents.

  15. Repellent Activities of Ocimum basilicum, Azadirachta indica and Eucalyptus citriodora Extracts on Rabbit Skin against Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Koech Peter Kiplang’at

    2013-10-01

    Full Text Available Vector borne diseases are the major public health problems in developing countries particularly in tropics. Essential oils from plants can provide the safe and biodegradable alternatives to synthetic repellents, but plant-based repellent formulations available in the market are not effective. The purpose of the study was to investigate mosquito repellent activities of Sweet Basil (Ocimum basilicum, Neem (Azadirachta indica and Lemon Eucalyptus (Eucalyptus citriodora extracts. Different concentrations of the extracts were tested for mosquito repellency on rabbit skin as the host of Aedes aegypti. Laboratory reared starved females were used for the tests and data collection was done by observational parameters based on frequency of mosquito landing and blood engorgement. Synergised Crude oleoresin extract of Pyrethrum and Ballet mosquito repellent® were included as positive test controls and Vaseline pure petroleum jelly® as a negative test control. The results showed that synergised Pyrethrum oleoresin showed complete protection at 0.1% as compared to Lemon Eucalyptus oil and Sweet Basil oil at 2% and 3% respectively (p<0.05. Neem oil and Ballet did not provide complete protection. The mean percent repellency of 5% Neem oil was 84.21 and that of Ballet was 66.84 (p<0.05. Sweet basil and Lemon Eucalyptus oils can be alternative to Pyrethrum as natural mosquito repellents from plant origin.

  16. Assessment of the repellent effect of Lippia alba essential oil and major monoterpenes on the cattle tick Rhipicephalus microplus.

    Science.gov (United States)

    Lima, A da Silva; Carvalho, J F de; Peixoto, M G; Blank, A F; Borges, L M F; Costa Junior, L M

    2016-03-01

    The control of Rhipicephalus microplus (Ixodida: Ixodidae) is achieved using synthetic acaricides. However, resistant tick populations are widespread around the world. Plant essential oils can act as repellents, keeping ticks away from hosts and decreasing the selection pressure on synthetic acaricides. The aim of this study was to evaluate the in vitro repellent effect of Lippia alba essential oil on R. microplus larvae. Leaves from two L. alba genotypes maintained under the same agronomic and environmental conditions were collected. Essential oil was extracted by hydrodistillation and analysed by gas chromatography-mass spectrometry (GC-MS). The major monoterpenes detected in the chemical analysis were commercially acquired and tested. For the repellency test, a glass rod was vertically fixed to measure active climbing of approximately 30 R. microplus larvae aged 14-21 days in response to essential oils and monoterpenes. Repellency was evaluated at 1 h, 3 h and 5 h after treatment. Variation in repellent action was detected between the genotypes. The major monoterpenes identified in the essential oils (limonene and carvone) showed low repellent effects in comparison with intact essential oils. Thus, the present results showed that L. alba essential oil contains bioactive compounds with great repellent activity against ticks that varies according to the plant genotype.

  17. Thermal imaging of water repellence breakdown and build up following surfactant application

    Science.gov (United States)

    Alsih, Abdulkareem; Leopold, Matthias; McGrath, Gavan

    2017-04-01

    Surfactants are used in dry land cropping systems to improve water infiltration in water repellent soils, yet the dynamic nature of water repellence during various seasons and the associated hydrologic changes are still poorly understood. Here we evaluate surface temperature changes of a water repellent sand in response to irrigation and surfactant applications, reflecting infiltration, evaporation, and energy balance changes across multiple wetting-drying cycles. Using a near-infrared thermal camera soil surface temperatures of 15 1m2 plots were recorded at 10 minute intervals for three weeks. Plots differed by the width of surfactant application bands ( 16 cm, 25 cm, 50 cm, and 100 cm wide surfactant bands as well as a control with no surfactant), individual treatments were replicated three times. Temporal changes in the spatial variability was examined using semivariograms and wavelets. The semivariogram analysis indicates that in contrast to the thinnest surfactant bands, wide bands lead to a gradual increase in soil-temperature heterogeneity towards that seen in a control. Wavelets and time-distance plots reveal a non-linear switch in soil temperature dynamics for surfactant treated plots which were absent in 100 cm band and control plots. This switch, evident in the relative temperature differences across the plot during diurnal cycling, was associated with a gradual drop in ambient temperatures. These results image water repellence breakdown in the field. The study demonstrates the general suitability of using thermal surface properties of water repellent soils to investigate the dynamics of water repellence breakdown. This knowledge can be used to test the efficiency of available and new surfactant products to overcome water repellency.

  18. Task familiarity and task efficacy: a study of sports coaches.

    Science.gov (United States)

    Fung, Lena

    2002-10-01

    The purpose of the study was to establish a profile of coaching efficacy with Hong Kong community coaches who differ in knowledge and hours spent in coaching. Coaching efficacy can be described in four dimensions, namely, Motivation, Strategy, Technique, and Character Building. It was hypothesized that coaches who had spent more time coaching and were more knowledgeable about the sport and coaching would score higher on those four dimensions of a Coaching Efficacy Scale. The scale was administered to 252 coaches working with beginning and district-level athletes in a variety of sports. Analysis suggested that their self-reported efficacy on Strategy was least strong. This means that the coaches were not confident in analyzing the strengths and weaknesses of opposing teams, making decisions on the type of game strategy to employ, and maximizing athletes' strength in competitions. Coaches with less coaching experience were also less confident about motivating athletes. This information on coaching efficacy may be useful in deciding content for a program of education for coaching.

  19. Vegetation type and the presence of ash as factors in the evolution of soil water repellency after a forest fire

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Pinilla

    2013-05-01

    Full Text Available After wildfires, burning may induce the occurrence of soil water repellency. Soil water repellency may vary in space and time in function of vegetation, the presence of ash and soil moisture. This study analyzes the evolution of fire-induced soil water repellency in function of these factors, and proposes measures to promote the restoration of fire-affected soils. Burnt and unburnt (control soil plots under pine and shrub from a recently burned area (Gorga, Alicante, SE Spain were established. Three treatments were applied: in some of the plots, the original ash layer was kept on the ground; in a second group, the ash layer was removed for simulating the effects of erosion; finally, in a third group, percolating irrigation was conducted to simulate a possible good input of water into the soil profile after burning, that could occur if the first rains were with high quantity but low intensity. During the dry season, soil moisture content was significantly lower in burned plots due to fire-induced water repellency and reduced vegetation cover. During the wet season, soil moisture decreased in the control unburnt plots due to direct evaporation of water intercepted by vegetation and consumption by roots. Fire increased soil water repellency only in plots under pine. Water repellency decreased during the wet season, disappearing in January and reappearing after declining rainfalls. This baseline recovery of soil water repellency was lower where ash removal was simulated. In unburned plots, seasonal fluctuations were less important. In general, ash removal promotes a rapid reduction of water repellency, since it can induce washing of hydrophobic compounds. Irrigation performed immediately after the fire also contributed to decreased water repellency.

  20. Self-Efficacy and IPS: An Empirical Study

    Science.gov (United States)

    McLeod, Linda P.

    2015-01-01

    The fact that some learners learn language more successfully than others who are at the same level of aptitude and capabilities is inevitable. To understand why, the researcher has focused her attention on individual differences among learners. The ones that have been taken into account in this study are namely called self-efficacy and identity…

  1. Fire impacts on water repellency of sandy soils in SW Spanish coast

    Science.gov (United States)

    Jordán, Antonio; Zavala, Lorena M.; Gordillo-Rivero, Ángel J.; Muñoz-Rojas, Miriam; Keesstra, Saskia; Cerdá, Artemi

    2017-04-01

    Although water repellency of sandy soils from dune areas and their consequences (irregular wetting front, preferential flow pathways) are well studied, there is not much information about the effect of fire on hydrophobicity and its consequences in these areas. In this paper we study the in-depth variation of water repellency of burnt sandy soils from south-western Spain. Generally, it was observed that water repellency from unburnt forest soils is relatively higher than in shrublands and grasslands (where the lowest values were observed). However, the impact of fire caused a strong increase of hydrophobicity in the first two cases, with no major differences between them. This study confirms the presence of natural water repellency in sandy soils, as well as some of its consequences (irregular infiltration or increased surface water flow) depending on the type of vegetation, although the differences observed in burnt soils suggest that, although the composition of vegetation is important in the formation of natural water repellency, organic matter content is much more important in the case of burnt soils.

  2. 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.

  3. Mosquito repellency of novel Trifluoromethylphenyl amides

    Science.gov (United States)

    Human diseases caused by mosquito-transmitted pathogens include malaria, dengue and yellow fever and are responsible for several million human deaths every year, according to the World Health Organization (WHO). Our current research projects focus on the development of new insecticides and repellent...

  4. Uneven moisture patterns in water repellent soils

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.

    1996-01-01

    In the Netherlands, water-repellent soils are widespread and they often show irregular moisture patterns, which cause accelerated transport of water and solutes to the groundwater and surface water. Under grass cover, spatial variability in soil moisture content is high owing to fingered flow; in ar

  5. Mode of action of insect repellents

    Science.gov (United States)

    The mode of action of DEET and other insect repellents has been a topic of interest since the discovery of DEET in the mid twentieth century. Nearly 60 years have passed since DEET applied topically to the skin was shown to be effective in preventing mosquito bites. With the discovery and characte...

  6. Methods for determining actual soil water repellence

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.; Oostindie, K.; Moore, D.; Wesseling, J.G.

    2009-01-01

    In this paper we describe a simple and quick method for determining the presence of water repellency in a soil by using a small core sampler (1.5 cm in diameter, 25 cm long) and applying the water drop penetration time (WDPT) test at different depths on the sandy soil cores. Obtained results provide

  7. Manufacturing and characterisation of water repellent surfaces

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Botija, Pablo; Hansen, Hans Nørgaard

    2006-01-01

    design criteria for such surfaces. The problem of adapting this behaviour to artificially roughened surfaces is addressed by providing design criteria for superhydrophobic, water-repellent and self-cleaning surfaces according to the concrete performance desired for them. Different kind of manufacturing...

  8. Pest repelling properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2014-01-01

    Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini...

  9. PERBANDINGAN EFEKTIFITAS REPELLENT KOMERSIL DENGAN EKSTRAK KULIT JERUK PURUT UNTUK MENCEGAH GIGITAN NYAMUK Aedes aegypti

    OpenAIRE

    Wana; Ishak, Hasanuddin; Manyullei, Syamsuar

    2015-01-01

    Repellent merupakan bahan yang mempunyai kemampuan untuk melindungi manusia dari gigitan nyamuk. Repellent kimia yang paling sering digunakan adalah repellent yang mengandung DEET yang beredar di supermarket, pasaran maupun warung-warung kecil. Selain itu adapula repellent alami yang dapat digunakan, yaitu kandungan minyak atsiri pada kulit jeruk purut. Penelitian ini bertujuan untuk membandingkan efektivitas repellent komersil yaitu repellent merek SL dan repellent alami yaitu minyak at...

  10. Angelica sinensis (Umbelliferae) with proven repellent properties against Aedes aegypti, the primary dengue fever vector in Thailand.

    Science.gov (United States)

    Champakaew, D; Junkum, A; Chaithong, U; Jitpakdi, A; Riyong, D; Sanghong, R; Intirach, J; Muangmoon, R; Chansang, A; Tuetun, B; Pitasawat, B

    2015-06-01

    Botanical resources with great diversity in medicinal and aromatic plants are a rich and reliable source for finding insect repellents of plant origin, which are widely popular among today's consumers. Although some herbal-based repellents have been proven comparable to or even better than synthetics, commercially available natural repellents generally tend to be expensive, with short-lived effectiveness. This critical flaw leads to ongoing research for new and effective repellents, which provide longer protection against vector and nuisance-biting insects, while remaining safe, user friendly, and reasonably priced. This study aimed to evaluate the repellent activity of plant-derived products against the primary dengue vector, Aedes aegypti, by following the human bait technique of World Health Organization guidelines. Preliminary laboratory screening tests for repellency of 33 plant species clearly demonstrated Angelica sinensis as the most effective repellent from each kind of extracted product, with its essential oil and ethanolic extract having median complete protection times of 7.0 h (6.0-7.5) and 2.5 h (2.0-2.5), respectively. Due to its low yield (0.02 %), pungent smell, and little cause of irritation, A. sinensis essential oil did not qualify as a candidate for further repellent assessment. However, subsequent extractions of A. sinensis with different organic solvents of increasing polarity provided four extractants with varying degrees of repellency against A. aegypti. The hexane extract of A. sinensis provided excellent repellency, with a median complete protection time of 7.5 h (6.5-8.5), which was longer than that of ethanol (2.5, 2.0-2.5 h), acetone (1.75, 0.5-2.5 h), and methanol extracts (0.5, 0-1.0 h). By being the most effective product, A. sinensis hexane extract gave significant protection comparable to that of its essential oil and the standard synthetic repellent, N,N-diethyl-3-methylbenzamide (DEET: 6.25, 5.0-6.5 h). Qualitative gas

  11. Assessment of the repellent effect of citronella and lemon eucalyptus oil against South African Culicoides species.

    Science.gov (United States)

    Venter, Gert J; Labuschagne, Karien; Boikanyo, Solomon N B; Morey, Liesl

    2014-08-08

    The use of insect repellents to reduce the attack rate of Culicoides species (Diptera:Ceratopogonidae) should form part of an integrated control programme to combat African horse sickness and other diseases transmitted by these blood-feeding midges. In the present study the repellent effects of a commercially available mosquito repellent, a combination of citronella and lemon eucalyptus oils, on Culicoides midges was determined. The number of midges collected with two 220 V Onderstepoort traps fitted with 8 W 23 cm white light tubes and baited with peel-stick patches, each containing 40 mg of active ingredient, was compared with that of two unbaited traps. Two trials were conducted and in each trial the four traps were rotated in two replicates of a 4 x 4 randomised Latin square design. Although more midges were collected in the baited traps, the mean number in the baited and unbaited traps was not significantly different. This mosquito repellent did not influence either the species composition or the physiological groups of Culicoides imicola Kieffer. The higher mean numbers in the baited traps, although not statistically significant, may indicate that this mosquito repellent might even attract Culicoides midges under certain conditions.

  12. Repellent activity of desiccant dusts and conidia of the entomopathogenic fungus Beauveria bassiana when tested against poultry red mites (Dermanyssus gallinae) in laboratory experiments.

    Science.gov (United States)

    Kilpinen, Ole; Steenberg, Tove

    2016-11-01

    Desiccant dusts and entomopathogenic fungi have previously been found to hold potential against the poultry red mite, which is an important pest in egg production and notoriously difficult to control. Both control agents may cause repellence in other arthropods and potentially also influence control levels adversely when used against the poultry red mite. Five desiccant dust products with good efficacy against the poultry red mite Dermanyssus gallinae caused avoidance behavior in mites when tested in bioassays. The repellent activity was correlated with efficacy, which was found to depend on both dose and relative humidity (RH). However, one desiccant dust was significantly less repellent compared to other dusts with similar levels of efficacy. Further, dry conidia of the fungus Beauveria bassiana were also shown to be repellent to poultry red mites, both when applied on its own and when admixed with a low dose of the desiccant dust Diamol. The pick-up of desiccant dust particles and fungus conidia from treated surfaces by mites did not differ depending on RH, whereas the overall efficacy of the two control agents were significantly higher at 75 than at 85 % RH. In addition, the combined effect of the two substances was synergistic when tested in a bioassay where mites could choose whether to cross a treated surface. This is the first time a member of Acari has been shown to be repelled by desiccant dusts and by conidia of an entomopathogenic fungus.

  13. In vitro repellent effect of tea tree (Melaleuca alternifolia) and andiroba (Carapa guianensis) oils on Haemotobia irritans and Chrysomya megacephala flies.

    Science.gov (United States)

    Klauck, V; Pazinato, R; Radavelli, W M; Volpato, A; Stefani, L M; Santos, R C V; Vaucher, R A; Boligon, A A; Athayde, M L; Da Silva, A S

    2015-03-01

    This study aimed to evaluate the repellent effect of tea tree (Melaleuca alternifolia) and andiroba (Carapa guianensis) essential oils on two species of flies (Haemotobia irritans and Chrysomya megacephala). For the in vitro studies, free-living adult flies were captured and reared in the laboratory. To verify the repellency effect, an apparatus was constructed where H. irritans and C. megacephala were exposed to andiroba and tea tree oils (5.0%), as well as to a known repellent (citronella, 5.0%) to validate the test. The study demonstrated that all three oils used showed in vitro repellent effect against both species of flies. It is possible to conclude that the essential oils (tea tree and andiroba) have repellent effect on these species of flies used in this study.

  14. Analysis Study of Survey for Safety and Efficacy of Pharmacopuncture

    OpenAIRE

    Hong Kwon-eui

    2010-01-01

    This study was done in order to present clinical trial method for safety and efficacy of Pharmacopuncture. The results were summarized as follow:Objective : The purpose of this study is to verify about safety and effectiveness of pharmacopuncture. Methods : We use questionnaire created by expert group. Survey was conducted to target clinicians who using pharmacopuncture more then 5 years. Results & Conclusion : Pharmacopuncture is effective. and that is widely used in the musculoskeleta...

  15. Larvicidal efficacy of Toddalia asiatica (Linn.) Lam against two ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-04-19

    Apr 19, 2010 ... ... due to their excellent properties like cheap availability, environmental ... compounds, such as larvicidal, repellent, insect growth regulators, antifeedants, ovicidal .... Efficacy of neem extract against the blowfly and housefly.

  16. 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.

  17. Study of Self-Efficacy Perceptions of Social Studies Teacher Candidates on Educational Internet Usage

    Science.gov (United States)

    Akman, Özkan

    2016-01-01

    This study aimed at examining the self-efficacy perceptions of social studies teacher candidates with respect to educational internet use. This research was conducted on a sample of 174 social studies teacher candidates enrolled in Gaziantep University Nizip Faculty of Education. The "Educational Internet Self-Efficacy Scale," developed…

  18. Physicochemical characterization of fish protein adlayers with bacteria repelling properties

    DEFF Research Database (Denmark)

    Meyer, R. L.; Arpanaei, A.; Pillai, S.;

    2013-01-01

    Materials coated with aqueous fish protein extracts can reduce bacterial adhesion, but the mechanism behind the observed effect is not fully understood. In this study we explore the physicochemical properties of fish muscle protein adlayers on four substrates: gold, stainless steel, polystyrene...... and silicon dioxide. The aims were (i) to determine if the anti-adhesive effect is independent of the underlying substrate chemistry, (ii) to link the physicochemical properties of the adlayer to its ability to repel bacteria, and (iii) to elucidate the mechanism behind this effect. The main proteins on all...

  19. Rodent repellents: Preparation and properties of thiouronium compounds and cyclic imides

    Science.gov (United States)

    Bellack, E.; DeWitt, J.B.

    1954-01-01

    Syntheses and bioassays of cyclic imides and thiouronium compounds were carried out as part of a search for materials capable of preventing rodent damage to packaged commodities. Previous studies had shown that repellent activity was associated with functional groups containing nitrogen and sulfur, and was enhanced by the presence of ionic linkages. Twenty-seven thiouronium compounds and 40 imides, including 1 0 compounds not described previously, were prepared for these tests. Ten imides and 26 thiouronium compounds were repellent under the conditions of test. Information obtained in these studies will be utilized in the development and selection of more effective materials for prevention of rodent damage to foods and other commodities.

  20. Basic soil properties as a factor controlling the occurrence and intensity of water repellency in rankers of the White Carpathians

    OpenAIRE

    Kořenková Lucia; Urík Martin

    2015-01-01

    Water repellency in soils is controlled by many different factors, basic physical and chemical properties might be considered the crucial ones. For the purpose of this study, 12 sites were selected and sampled (0–20 cm depth) in the White Carpathians. Repellency tests were conducted under laboratory conditions in triplicate using water drop penetration time (WDPT) test and the molarity of ethanol droplet (MED) test. Results of WDPT measurements showed that three samples were marked by slight ...

  1. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina against Aedes aegypti and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Raimundo Wagner Souza Aguiar

    Full Text Available This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult and Aedes albopictus (C6/36 cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min and in contact with cultured insect cells (C6/36 induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  2. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Aguiar, Raimundo Wagner Souza; dos Santos, Suetonio Fernandes; da Silva Morgado, Fabricio; Ascencio, Sergio Donizeti; de Mendonça Lopes, Magnólia; Viana, Kelvinson Fernandes; Didonet, Julcemar; Ribeiro, Bergmann Morais

    2015-01-01

    This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  3. [Repellent and antifeedant effect of secondary metabolites of non-host plants on Plutella xylostella].

    Science.gov (United States)

    Wei, Hui; Hou, Youming; Yang, Guang; You, Minsheng

    2004-03-01

    Based on the theory of co-evolution between plants and phytophagous insects, the repellent and antifeedant effect of secondary metabolites of non-host plants on diamondback moth(DBM) Plutella xylostella was studied, aimed at finding out the oviposition repellents and antifeedants of insect pests. When the ethanol extracts(Etho Exts) of Bauhinia variegata, Eucalyptus tereticornis, Euphorbia hirta, Duranta repens, Zanthoxylum bungeanum, Magnolia grandiflora, and Nicotiana tabacum were applied respectively, the oviposition repellent rates were all over 80.00%; while after forty-eight hours treatment with the Etho Exts of Euphorbia pulcherrima, Broussonetia papyrifera, Artemisia argyi, Camellia oleifera, Salix babylonica, Euphorbia hirta, Bauhinia variegata, and Setaria viridisa, the antifeedant rates of DBM larvae were all more than 80.00%.

  4. Monitoring fire impacts in soil water repellency and structure stability during 6 years

    Directory of Open Access Journals (Sweden)

    A.J. Gordillo-Rivero

    2013-05-01

    Full Text Available Wildfires induce a series of soil changes affecting their physical and chemical properties and the hydrological and erosive response. Two of the properties that are commonly affected by burning are soil water repellency and structural stability. This paper carries out the study and monitoring of water repellency and soil structural stability during a period of 6 years after fire in calcareous soils of southern Spain in different aggregate size fractions (<2, 1-2, 0.5-1 and 0.25-0.5 mm. During this time, it was observed that both properties showed different tendencies in different aggregate size fractions. It was observed that water repellency increased after fire especially in the finer fractions (0.25-0.5 mm. Structural stability increased significantly after the fire and was progressively reduced during the experimental period.

  5. Composition and structure of agents responsible for development of water repellency in soils following oil contamination.

    Science.gov (United States)

    Litvina, Marina; Todoruk, Tiona R; Langford, Cooper H

    2003-07-01

    Soil from the Ellerslie site of experimental oil contamination in Alberta developed water repellency some years after initial remediation. The water-repellent soils were compared to clean soils and contaminated but wettable soils by solid-state nuclear magnetic resonance (NMR). The effects of extraction with CH2Cl2 (for petroleum hydrocarbons), NaOH (for natural organic matter), and 2-propanol/ammonia (IPA/NH3) on wettability were evaluated by the molarity of the ethanol droplet (MED) test. Soil extracts and whole soils, after extraction, were examined using NMR and Fourier transform infrared spectroscopy (FTIR). On the basis of the structure--MED correlations, a model of a thin-layer natural organic matter--petroleum products complex formed under strong drying conditions is proposed to account for the development of water repellency. Studies of two similar soils from accidental oil spills are supportive.

  6. Insecticidal and insect-repellent activities of essential oils from Verbenaceae and Anacardiaceae against Rhizopertha dominica.

    Science.gov (United States)

    Benzi, Verónica S; Murrayb, Ana P; Ferrero, Adriana A

    2009-09-01

    Essential oils extracted from leaves of Aloysia polystachya and A. citriodora (Verbenaceae) and from leaves and fruits of Schinus molle var. areira (Anacardiaceae) were tested for their repellent and toxic activities against adults of Rhizopertha dominica (Coleoptera: Bostrichidae). Topical application and filter paper assays were employed for contact toxicity studies; filter paper impregnation was also used for fumigant and repellent assays. In topical tests A. polystachya was as effective as S. molle leaves. In the case of repellent assays, A. citriodora was the most effective oil based on the class scale. A. polystachya was the most toxic plant on contact toxicity by filter paper assay (LC50 26.6 mg/cm2). Fumigant toxicity was only evaluated with fruits and leaves of S. molle, and no significant differences were found between them. Published data are included to compare the fumigant toxicity of S. molle with that of A. citridora and A. polystachya.

  7. Alflutop clinical efficacy assessment in osteoarthritis (two-years study)

    OpenAIRE

    V. N. Chodyrev; N I Znaisheva; G M Lobanova; L M Ridnyak

    2003-01-01

    Objective. To assess alflutop clinical efficacy and safety during long-term course treatment of knee osteoarthritis. Methods. 51 pts with definite knee osteoarthritis of I-III stage according to Kellgren-Lawrence classification were included in an open controlled study. 20 pts received 6 intra-articular injections of alflutop 2 ml with subsequent intramuscular treatment during 3 months. Such courses were repeated 6 months apart for 2 years. 31 pts of control group received nonsteroidal anti-i...

  8. CO2 response to rewetting of hydrophobic soils - Can soil water repellency inhibit the 'Birch effect'?

    Science.gov (United States)

    Sanchez-Garcia, Carmen; Urbanek, Emilia; Doerr, Stefan

    2017-04-01

    Rewetting of dry soils is known to cause a short-term CO2 pulse commonly known as the 'Birch effect'. The displacement of CO2 with water during the process of wetting has been recognised as one of the sources of this pulse. The 'Birch effect' has been extensively observed in many soils, but some studies report a lack of such phenomenon, suggesting soil water repellency (SWR) as a potential cause. Water infiltration in water repellent soils can be severely restricted, causing overland flow or increased preferential flow, resulting in only a small proportion of soil pores being filled with water and therefore small gas-water replacement during wetting. Despite the suggestions of a different response of CO2 fluxes to wetting under hydrophobic conditions, this theory has never been tested. The aim of this study is to test the hypothesis that CO2 pulse does not occur during rewetting of water repellent soils. Dry homogeneous soils at water-repellent and wettable status have been rewetted with different amounts of water. CO2 flux as a response to wetting has been continuously measured with the CO2 flux analyser. Delays in infiltration and non-uniform heterogeneous water flow were observed in water repellent soils, causing an altered response in the CO2 pulse in comparison to typically observed 'Birch effect' in wettable systems. The main conclusion from the study is that water repellency not only affects water relations in soil, but has also an impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  9. Measuring and understanding soil water repellency through novel interdisciplinary approaches

    Science.gov (United States)

    Balshaw, Helen; Douglas, Peter; Doerr, Stefan; Davies, Matthew

    2017-04-01

    Food security and production is one of the key global issues faced by society. It has become evermore essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The failure of soil to absorb water - soil water repellency - can lead to major environmental problems such as increased overland flow and soil erosion, poor uptake of agricultural chemicals and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. Understanding the causes of soil hydrophobicity is essential for the development of effective methods for its amelioration, supporting environmental stability and food security. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor in causing soil water repellency. It is widely accepted that the main groups of compounds responsible are long-chain acids, alkanes and other organic compounds with hydrophobic properties. However, when reapplied to sands and soils, the degree of water repellency induced by these compounds and mixtures varied widely with compound type, amount and mixture, in a seemingly unpredictable way. Our research to date involves two new approaches for studying soil wetting. 1) We challenge the theoretical basis of current ideas on the measured water/soil contact angle measurements. Much past and current discussion involves Wenzel and Cassie-Baxter models to explain anomalously high contact angles for organics on soils, however here we propose that these anomalously high measured contact angles are a consequence of the measurement of a water drop on an irregular non-planar surface rather than the thermodynamic factors of the Cassie-Baxter and Wenzel models. In our analysis we have successfully used a much simpler geometric approach for non-flat surfaces such as soil. 2) Fluorescent and phosphorescent

  10. Length of tick repellency depends on formulation of the repellent compound (icaridin = Saltidin®): tests on Ixodes persulcatus and Ixodes ricinus placed on hands and clothes.

    Science.gov (United States)

    Abdel-Ghaffar, Fathy; Al-Quraishy, Saleh; Mehlhorn, Heinz

    2015-08-01

    The present study had the aim to test the repellent potential of the compound icaridin = Saltidin® against the tick species Ixodes ricinus and Ixodes persulcatus using different formulations of the compound. Tests were done on backs of impregnated human hands, on impregnated linen cloth and versus impregnated dog hair. It was found that 1. Ixodes persulcatus-the common Eastern European, Russian Ixodes species is significantly sensitive to icaridin = Saltidin® as I. ricinus protecting for the test period of 5 h. This is an important finding, since I. persulcatus is the vector of agents of the severe Eastern meningoencephalitis; 2. that this repellent compound acts similarly on both I. ricinus and I. persulcatus, when sprayed either on naked skin or on cloths; 3. that there are only slight differences in duration of the repellency when using different formulations containing icaridin = Saltidin®; 4. that icaridin = Saltidin® sprayed on dog hair has identical repellent effects like those seen on human skin and cloths; thus, this compound can also be used to protect animals such as dogs, cats, horses; and 5. that the icaridin = Saltidin® did not induce a bad sensation on skin, nor bad smells; furthermore, it was not sticky and did not leave residuals neither on clothes nor on dog's hair.

  11. Laboratory evaluation of traditional insect/mosquito repellent plants against Anopheles arabiensis, the predominant malaria vector in Ethiopia.

    Science.gov (United States)

    Karunamoorthi, Kaliyaperumal; Mulelam, Adane; Wassie, Fentahun

    2008-08-01

    Laboratory study was carried out to evaluate the repellent efficiency of most commonly known four traditional insect/mosquito repellent plants Wogert [vernacular name (local native language, Amharic); Silene macroserene], Kebercho [vernacular name (local native language, Amharic); Echinops sp.], Tinjut [vernacular name (local native language, Amharic); Ostostegia integrifolia], and Woira[vernacular name (local native language, Amharic); Olea europaea] against Anopheles arabiensis under the laboratory conditions. One hundred (4-5 days old) female A. arabiensis were introduced into the both 'control' and 'test' repellent chamber through the hole on top. Traditional charcoal stoves were used for direct burning. The experiment was conducted by applying the smoke into the repellent "test" mosquito cage by direct burning of 25 gm of dried plant materials (leaves and roots) until plant materials completely burned. The number of mosquitoes driving away from the "test" and "control" cage was recorded for every 5 min. In the present investigation, the results clearly revealed that the roots of S. macroserene has potent repellent efficiency (93.61%) and was the most effective. The leaves of Echinops sp. (92.47%), leaves of O. integrifolia (90.10%) and O. europaea (79.78%) were also effective. Roots of S. macroserene exhibited the highest repellent efficiency by direct burning. The present study identified these four traditional indigenous insect/mosquito repellent plant materials are very promising and can be used as safer alternative to modern synthetic chemical repellents against mosquito vectors of disease. Since people have been using these plants for some medicinal purposes, no side effects have been found.

  12. Soil respiration (CO2 efflux) response to spatio-temporal variability of soil water repellency

    Science.gov (United States)

    Urbanek, Emilia; Doerr, Stefan

    2017-04-01

    Soil water repellency (SWR) is a common feature of many soils which restricts water infiltration and movement within the soil. SWR is expected to become more spread according to current climatic prediction, but its effect on soil carbon dynamics and specifically on soil CO2 fluxes is still not clear. Based on previous laboratory experiments it has been suggested that water repellency reduces soil respiration, but the responses of soil CO2 efflux to naturally varying hydrological conditions created by SWR are not yet known. This is the first field-based study testing the hypothesis that water repellency indeed reduces soil CO2 efflux. In situ field measurements of soil CO2 fluxes, temperature, water contents and water repellency were carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. SWR was observed for the majority of the warmer period, but exhibited high spatial variability. Soils showed similar levels of extreme water repellency only on a few occasions following long dry spells and this indeed resulted in reduction in CO2 efflux. Spatially patchy SWR with variable soil moisture content induced the highest respiration rates, significantly higher than when SWR was absent. This rather unexpected behaviour can be explained by SWR-induced preferential flow which created flow paths with water and nutrients supply to the microorganisms, while water repellent zones provided air-filled pathways to facilitate soil-atmosphere gas exchanges. This study demonstrates that SWR can have contrasting effects on CO2 fluxes and, when spatially-variable, enhance CO2 efflux.

  13. Ice repellency behaviour of superhydrophobic surfaces: Effects of atmospheric icing conditions and surface roughness

    Energy Technology Data Exchange (ETDEWEB)

    Momen, G., E-mail: gmomen@uqac.ca; Jafari, R.; Farzaneh, M.

    2015-09-15

    Highlights: • A novel view on ice repellency of superhydrophobic surfaces in terms of contact angle hysteresis, roughness and icing condition has been discussed. • This study is the first to deal with the effect of icing parameters on the ice repellency behaviour of superhydrophobic surfaces. • Two fabricated superhydrophobic surfaces with similar wettability behaviour showed different icephobic behaviour. • Superhydrophobic surfaces are not always icephobic and ice repellency is governed by icing condition parameters like liquid water content and water droplet size. • Lower liquid water content and smaller water droplet size promote ice-repellency behaviour of superhydrophobic surfaces. - Abstract: This paper presents a novel view on ice repellency of superhydrophobic surfaces in terms of contact angle hysteresis, surface roughness and icing condition. Ice repellency performance of two superhydrophobic silicone rubber nanocomposite surfaces prepared via spin coating and spray coating methods were investigated. High contact angle (>150°), low contact angle hysteresis (<6°) and roll-off property were found for both spin and spray coated samples. The results showed a significant reduction of ice adhesion strength on the spin-coated sample while ice adhesion strength on the spray-coated sample was found to be unexpectedly similar to that of the uncoated sample. Indeed, this research study showed that the icephobic properties of a surface are not directly correlated to its superhydrphobicity and that further investigations, like taking icing condition effect into account, are required. It was found that icephobic behaviour of the spray coated sample improved at lower levels of liquid water content (LWC) and under icing conditions characterized by smaller water droplet size.

  14. Microencapsulation of essential oil for insect repellent in food packaging system.

    Science.gov (United States)

    Chung, Seong Kyun; Seo, Ji Yeon; Lim, Jung Hoon; Park, Hyung Hwan; Yea, Myeong Jai; Park, Hyun Jin

    2013-05-01

    Microcapsules containing thyme oil were prepared by in situ polymerization, using melamine-formaldehyde prepolymer as a wall material and 3 different emulsifiers (pluronic F-127, tween 80, and sodium lauryl sulfate [SLS]). The general characteristics and release behavior of microcapsules, and their repellent effect against insects were investigated. The morphology of microcapsules using SLS was spherical shape with smooth surface. Microcapsules began to degrade at 150 °C. The particle size ranged from 1 to 10 μm and the loading efficiency of thyme oil was clearly affected by the emulsifier type. The highest loading efficiency appeared in microcapsules using SLS, which have good thermal resistance and smooth surface. The release rate of thyme oil from microcapsules was not only dependent on the storage temperature but also emulsifier type and microcapsules showed the sustained release properties for a long time. Diets, which were mixed with encapsulated thyme oil, expressed high insect repellent efficacy over 90% for 4 wk.

  15. Effects of soil water repellency on microbial community structure and functions in Mediterranean pine forests

    Science.gov (United States)

    Lozano, Elena; Grayston, Sue J.; Mataix-Solera, Jorge; Arcenegui, Victoria; Jimenez-Pinilla, Patricia; Mataix-Beneyto, Jorge

    2015-04-01

    Soil water repellency (SWR) is a property commonly observed in forest areas showing wettable and water repellent patches with high spatial variability. SWR can greatly influence the hydrology and the ecology of forest soils. The capacity of soil microorganisms to degrade different organic compounds depends upon species composition, so this may affect changes in SWR on the microsite scale (such as the presence of soil water repellent patches; Mülleret al., 2010). In the Mediterranean forest context, SWR has been found to be related to microbial community composition. The accumulation of different hydrophobic compounds might be causing the shifts in microbial community structure (Lozano et al., 2014). In this study we investigated the effects of SWR persistence on soil microbial community structure and enzyme activity under Pinus halepensis forest in three different sites: Petrer, Gorga and Jávea (Alicante, E Spain). Soil samples were classified into three different water repellency classes (wettable, slight or strongly water repellent samples) depending on the SWR persistence. The soil microbial community was determined through phospholipid fatty acids (PLFAs). Enzyme activities chosen for this study were cellulase, β-glucosidase and N-acetyl-β-glucosaminide (NAG). The relationships between microbiological community structure and some soil properties such as pH, Glomalin Related Soil Protein, soil organic matter content and soil respiration were also studied. Redundancy analyses and decomposition of the variances were performed to clarify how microbial community composition and enzyme activities are affected by SWR and soil properties. The effect of SWR on microbial community composition differed between locations. This effect was clearer in the Petrer site. Enzyme activity varied considerably depending on SWR persistence. The highest activities were found in slightly SWR samples and the lowest mostly in the strongly water repellent ones. These preliminary

  16. Rural buyers' perception about mosquito repellants

    OpenAIRE

    Mehta, D.; Anand GARG; Naveen K MEHTA

    2010-01-01

    Mosquito repellants prevent mosquito bites and prevention of "man-mosquito contact" is a critical factor in transmission and spread of any disease through mosquitoes particularly in rural area. There has been a long standing 'bias' towards rural buyers. The rural markets are considered rigid in the nature but it is not the case in real sense. Marketing to rural buyers is not only a challenge to the marketers but to the manufacturers, communicators, national planners and economists as well. Th...

  17. Application Study on the Efficacy of New-type Mosquito Repellents%新型驱蚊贴的应用研究

    Institute of Scientific and Technical Information of China (English)

    姚英娟; 薛东; 杨长举

    2003-01-01

    本文通过对20种精油、中草药、派烯等单剂和3种优选单剂的复配配方的Y形嗅觉仪试验,结果表明20种单剂间有差异,筛选出3种最优单剂为18,15,3,驱避率分别为66.67%,60.,58.89%,三种优选单剂间的三种复配配方间没有显著差异,其驱避率分别为57.58%、66.67%、66.67%,并研究出一种新型的驱蚊剂型贴剂,在应用中有进一步研究的必要性.

  18. Repellent effect of some household products on fly attraction to cadavers.

    Science.gov (United States)

    Charabidze, Damien; Bourel, Benoit; Hedouin, Valery; Gosset, Didier

    2009-08-10

    The most common task of a forensic entomologist is to determine an accurate minimum post-mortem interval (PMI) using necrophagous fly larvae found on carrion. More often, blowflies (Diptera: Calliphoridae) are the first insects to detect the cadaver and, if the circumstances are favourable, to leave eggs on the body. However, several studies reveal that products such as gas or paint found on the cadaver induce a delay in the colonisation of the body, leading to an under-estimate of the PMI. Six common household products (gas, mosquito citronella repellent, perfume, bleach, hydrochloric acid and soda) were added to dead rats (Rattus norvegicus) in a field (Lille Forensic Institute, France). The presence of necrophagous flies was checked at regular intervals during 1 month. This experiment was repeated at the same period for four consecutive years. Results clearly showed the repellent effect of three of the six tested substances: gas (petroleum spirit), perfume and mosquito citronella repellent, which resulted in a mean delay of several days in the appearance of the first Dipteran species. Experiments were then carried out in controlled conditions in order to confirm previous observations. An olfactometer was specially designed to observe the behaviour of female Calliphora vicina (Diptera: Calliphoridae) in response to mice (Mus musculus) cadaver odour stimuli combined with household products. Dead mouse odour was a strong attractive stimulus for most of the tested individuals. Furthermore, it was noticed that the presence of mosquito citronella repellent, perfume, hydrochloric acid and paradichlorobenzene produced a significant repellent effect on female flies. All these results together confirm the repellent effect of some household products on flies and the necessity for forensic entomologists to consider this hypothesis when estimating the PMI.

  19. Effect of Thickness of a Water Repellent Soil Layer on Soil Evaporation Rate

    Science.gov (United States)

    Ahn, S.; Im, S.; Doerr, S.

    2012-04-01

    A water repellent soil layer overlying wettable soil is known to affect soil evaporation. This effect can be beneficial for water conservation in areas where water is scarce. Little is known, however, about the effect of the thickness of the water repellent layer. The thickness of this layer can vary widely, and particularly after wildfire, with the soil temperature reached and the duration of the fire. This study was conducted to investigate the effect of thickness of a top layer of water repellent soil on soil evaporation rate. In order to isolate the thickness from other possible factors, fully wettable standard sand (300~600 microns) was used. Extreme water repellency (WDPT > 24 hours) was generated by 'baking' the sand mixed with oven-dried pine needles (fresh needles of Pinus densiflora) at the mass ratio of 1:13 (needle:soil) at 185°C for 18 hours. The thicknesses of water repellent layers were 1, 2, 3 and 7 cm on top of wettable soil. Fully wettable soil columns were prepared as a control. Soil columns (8 cm diameter, 10 cm height) were covered with nylon mesh. Tap water (50 ml, saturating 3 cm of a soil column) was injected with hypoderm syringes from three different directions at the bottom level. The injection holes were sealed with hot-melt adhesive immediately after injection. The rate of soil evaporation through the soil surface was measured by weight change under isothermal condition of 40°C. Five replications were made for each. A trend of negative correlation between the thickness of water repellent top layer and soil evaporation rate is discussed in this contribution.

  20. Laser scanning confocal microscopy characterization of water repellent distribution in a sandstone pore network.

    Science.gov (United States)

    Zoghlami, Karima; Gómez-Gras, David; Corbella, Mercè; Darragi, Fadila

    2008-11-01

    In the present work, we propose the use of the Laser Scanning Confocal Microscopy (LSCM) to determine the effect of water repellents on rock's pore-network configuration and interconnection. The rocks studied are sandstones of Miocene age, a building material that is commonly found in the architectural heritage of Tunisia. The porosity quantitative data of treated and untreated samples, obtained by mercury porosimetry tests, were compared. The results show a slight decrease in total porosity with the water repellent treatment, which reduced both microporosity and macroporosity. This reduction produced a modification in pore size distribution and a shift of the pore access size mode interval toward smaller pore diameters (from the 30-40 microm to the 20-30 microm intervals). The water repellent was observed in SEM images as a continuous film coating grain surfaces; moreover, it was easily visualized in LSCM, by staining the water repellent with Epodye fluorochrome, and the coating thickness was straightforwardly measured (1.5-2 microm). In fact, the combination of mercury intrusion porosimetry data and LSCM observations suggests that the porosity reduction and the shift of the pore diameter mode were mainly due to the general reduction of pore diameters, but also to the plugging of the smallest pores (less than 3-4 microm in diameter) by the water repellent film. Finally, the LSCM technique enabled the reconstruction of 3D views of the water repellent coating film in the pore network, indicating that its distribution was uniform and continuous over the 100 microm thick sample. The LSCM imaging facilitates the integration and interpretation of mercury porosimetry and SEM data.

  1. 'Natural background' soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

    Science.gov (United States)

    Doerr, S.H.; Woods, S.W.; Martin, D.A.; Casimiro, M.

    2009-01-01

    Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle (??sl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is

  2. Water repellency diminishes peatland evaporation after wildfire

    Science.gov (United States)

    Kettridge, Nick; Lukenbach, Max; Hokanson, Kelly; Devito, Kevin; Hopkinson, Chris; Petrone, Rich; Mendoza, Carl; Waddington, Mike

    2016-04-01

    Peatlands are a critically important global carbon reserve. There is increasing concern that such ecosystems are vulnerable to projected increases in wildfire severity under a changing climate. Severe fires may exceed peatland ecological resilience resulting in the long term degradation of this carbon store. Evaporation provides the primary mechanisms of water loss from such environments and can regulate the ecological stress in the initial years after wildfire. We examine variations in evaporation within burned peatlands after wildfire through small scale chamber and large scale remote sensing measurements. We show that near-surface water repellency limits peatland evaporation in these initial years post fire. Water repellent peat produced by the fire restricts the supply of water to the surface, reducing evaporation and providing a strong negative feedback to disturbance. This previously unidentified feedback operates at the landscape scale. High surface temperatures that result from large reductions in evaporation within water repellent peat are observed across the 60,000 ha burn scar three months after the wildfire. This promotes high water table positions at a landscape scale which limit the rate of peat decomposition and supports the post fire ecohydrological recovery of the peatlands. However, severe burns are shown to exceed this negative feedback response. Deep burns at the peatland margins remove the hydrophobic layer, increasing post fire evaporation and leaving the peatland vulnerable to drying and associated ecological shifts.

  3. Preliminary Study of the Influence of Mosquito-repellent Incense on Radon Progeny Concentration in the Air-conditioned Room%蚊香对空调房内氡子体浓度影响的初步研究

    Institute of Scientific and Technical Information of China (English)

    李雯

    2012-01-01

    本文采用专业氡测量仪AlphaGUARD PQ2000PRO及其子体附件AlphaPM监测空调房内普通盘式蚊香及电热蚊香产生的气溶胶颗粒对氡子体浓度变化的影响。通过对比测量,可以看出普通盘式蚊香和电热蚊香产生的亚微米级气溶胶均会使得空调房内氡子体浓度增高,且前者导致的增加趋势更明显。建议开空调时室内使用电热蚊香,并且应定时开窗通风十几分钟,以降低室内氡子体浓度,减少其对人体的危害。%In this paper, the influence of aerosol particles produced by mosquito-repellent incense and electric heating mosquito-repellent incense on radon progeny concentration in the air-conditioned room was measured by professional radon monitor AlphaGUARD PQ2000PRO and its accessory AlphaPM. By comparing the measurements, it can be seen that the submicron aerosols produced by both mosquito-repellent incense and electric heating mosquito-repellent incense will make radon progeny concentration in the air-conditioned room increase, and the increasing trend caused by the former one is more obvious. The electric heating mosquito-repellent incense is recommended to be used in the air-conditioned room and windows should be open at the fixed time to reduce radon progeny concentration indoor, thereby reducing its harm to the human body.

  4. A Study on Emotional Healing Efficacy of Fiction for Undergraduate

    Directory of Open Access Journals (Sweden)

    Chen Su-May Sheih

    2014-01-01

    Full Text Available In modern society, undergraduates may encounter multiple pressures and thus feel the sense of alienation, anxiety, disturbance and depression. For undergraduates, reading can be independently conducted without the intervention of an instructor; therefore, undergraduates who feel reluctant to expose private emotions to counselors can help themselves through the reading of emotional healing books. This is the application of bibliotherapy. Among various resources, fiction can serve as an appropriate emotional reading material. The researcher deployed semi-structured in-depth interview, and interviewed 21 undergraduates in Taipei City and Taipei County. This study is aimed to understand the kinds of fictions undergraduates read when they are upset and to analyze the emotional healing process of identification, catharsis, and insight so that the emotional healing efficacy can be evaluated. The findings showed that romance, realistic fiction, fantasy, martial arts novel, inspirational fiction, historical fiction, and science fiction can provide full process of emotional healing efficacy. However, detective fiction, online novel, psychological fiction, and horror fiction can only provide parts of the healing process. Besides, the healing efficacy of a specific fiction is different from reader to reader.

  5. Alflutop clinical efficacy assessment in osteoarthritis (two-years study

    Directory of Open Access Journals (Sweden)

    V. N. Chodyrev

    2003-01-01

    Full Text Available Objective. To assess alflutop clinical efficacy and safety during long-term course treatment of knee osteoarthritis. Methods. 51 pts with definite knee osteoarthritis of I-III stage according to Kellgren-Lawrence classification were included in an open controlled study. 20 pts received 6 intra-articular injections of alflutop 2 ml with subsequent intramuscular treatment during 3 months. Such courses were repeated 6 months apart for 2 years. 31 pts of control group received nonsteroidal anti-inflammatory drugs (NSAID only. Pain on visual analog scale, Leken functional score, changes of NSAID treatment and radiological picture were used for assessment of efficacy. Clinical examination was performed before and after every treatment course and 3 months after the last course. Results. Every alflutop treatment course provided significant stepwise decrease of pain with improvement of mobility, reduction of NSAID requirement and absence of osteoarthritis radiological progression. Doctor and pts clinical efficacy and safety assessment coincided. Conclusion. Alflutop is an effective drug for knee osteoarthritis treatment. It has anti-inflammatory and probably chondroprotective activity with good safety.

  6. Water repellency of clay, sand and organic soils in Finland

    Directory of Open Access Journals (Sweden)

    K. RASA

    2008-12-01

    Full Text Available Water repellency (WR delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95 at the time of sampling. WR increased as follows: sand (R = 1.8-5.0 < clay (R = 2.4-10.3 < organic (R = 7.9-undefined. At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr., where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

  7. Repellency of cassia bark, eucalyptus, and star anise oils and their major constituents to Leptotrombidium pallidum (Acari: Trombiculidae).

    Science.gov (United States)

    Shin, E-Hyun; Song, Bong Gu; Lee, Il Hee; Park, Mi Yeoun; Ahn, Young-Joon; Chang, Kyu-Sik

    2013-05-01

    Leptotrombidium pallidum (Nagoya, Miyagawa, Mitamura & Tamiya) is a primary vector of Orientia tsutsugamushi (Hyashi), the causative agent of scrub typhus. An assessment is made of the repellency to L. pallidum larvae (chiggers) of cassia bark, eucalyptus, and star anise oils and major constituents (E)-cinnamaldehyde, 1,8-cineole, and (E)-anethole of the corresponding oils. Results were compared with those of conventional repellents DEET (N,N-diethyl-3-methylbenzamide), IR3535 [(ethyl 3-[acetyl(butyl)amino]propanoate)], and permethrin. Based on the median repellent concentration (RC50) values, (E)-cinnamaldehyde, (E)-anethole, cassia bark oil, and star anise oil (RC50, 0.95-1.52 mg/cm2) exhibited significantly more potent repellency than DEET (3.85 mg/cm2). (E)-cinnamaldehyde, (E)-anethole, cassiabark oil, 1,8-cineole, and star anise oil were approximately 43, 16, 11, 8, and 4 times more effective than IR3535 (CC5, 6.51%) as judged by the median climbing distance-disturbing concentration (CC50) values. The median residual duration time of repellency (RT50) was significantly more pronounced in DEET (RT50, 323 min) than in all essential oils and constituents (108-167 min). In the light of global efforts to reduce the level of highly toxic synthetic repellents, the three essential oils and their major constituents described merit further study as potential biorepellents for the control of L. pallidum populations.

  8. Premarket safety and efficacy studies for ADHD medications in children.

    Directory of Open Access Journals (Sweden)

    Florence T Bourgeois

    Full Text Available Attention-deficit hyperactivity disorder (ADHD is a chronic condition and pharmacotherapy is the mainstay of treatment, with a variety of ADHD medications available to patients. However, it is unclear to what extent the long-term safety and efficacy of ADHD drugs have been evaluated prior to their market authorization. We aimed to quantify the number of participants studied and their length of exposure in ADHD drug trials prior to marketing.We identified all ADHD medications approved by the Food and Drug Administration (FDA and extracted data on clinical trials performed by the sponsor and used by the FDA to evaluate the drug's clinical efficacy and safety. For each ADHD medication, we measured the total number of participants studied and the length of participant exposure and identified any FDA requests for post-marketing trials.A total of 32 clinical trials were conducted for the approval of 20 ADHD drugs. The median number of participants studied per drug was 75 (IQR 0, 419. Eleven drugs (55% were approved after <100 participants were studied and 14 (70% after <300 participants. The median trial length prior to approval was 4 weeks (IQR 2, 9, with 5 (38% drugs approved after participants were studied <4 weeks and 10 (77% after <6 months. Six drugs were approved with requests for specific additional post-marketing trials, of which 2 were performed.Clinical trials conducted for the approval of many ADHD drugs have not been designed to assess rare adverse events or long-term safety and efficacy. While post-marketing studies can fill in some of the gaps, better assurance is needed that the proper trials are conducted either before or after a new medication is approved.

  9. Larvicidal and repellent activity of tetradecanoic acid againstAedes aegypti (Linn.) andCulex quinquefasciatus (Say.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Sivakumar R; Jebanesan A; Govindarajan M; Rajasekar P

    2011-01-01

    Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegypti (Ae. aegypti) L. andCulex quinquefasciatus (Cx. quinquefasciatus) Say (Diptera: Culicidae).Methods: Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae. aegypti andCx. quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz.,1.0,2.5 and5.0 ppm under the laboratory conditions.Results: The tetradecanoic acid was found to be more effective againstCx. quinquefasciatus thanAe. aegypti larvae. TheLC50values were14.08 ppm and25.10 ppm, respectively. Tetradecanoic acid showed lesser repellency againstAe. aegypti andCx. quinquefasciatus. The highest repellency was observed in higher concentration of5.0 mg/cm2provided100% protection up to60 and 90 min againstAe. aegypti andCx. quinquefasciatusrespectively.Conclusions: From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx. quinquefasciatus andAe. aegypti mosquitoes.

  10. Nootkatone is a repellent for Formosan subterranean termite (Coptotermes formosanus).

    Science.gov (United States)

    Zhu, B C; Henderson, G; Chen, F; Maistrello, L; Laine, R A

    2001-03-01

    We examined the behavior of Formosan subterranean termites toward one of the components of vetiver grass oil, the roots of which manufacture insect repellents. We found nootkatone, a sesquiterpene ketone, isolated from vetiver oil is a strong repellent and toxicant to Formosan subterranean termites. The lowest effective concentration tested was 10 micrograms/g substrate. This is the first report of nootkatone being a repellent to insects.

  11. Measurements of infiltration and water repellency on different soils

    OpenAIRE

    Lavrač, Rožle

    2012-01-01

    Infiltration is a process of water entering soil from its surface. Field measurements of infiltration are performed with infiltrometers. Calculation of hydraulic conductivity can be done by different equations. Infiltration exhibits large spatial and temporal variability due to many affecting factors. One of those effects is soil water repellency (hydrophobicity). Water-repellent soils do not wet up spontaneously. The intensity and persistence of water repellency vary widely due to variabilit...

  12. 岷江上游干旱河谷旱地土壤斥水性特征初步研究%Preliminary Study on the Characteristics of Soil Repellency in the Dry Valley of Minjiang River

    Institute of Scientific and Technical Information of China (English)

    秦纪洪; 赵利坤; 孙辉; 李沙

    2012-01-01

    土壤斥水性是土壤颗粒不易被水滴浸润的现象,对土壤水分特征曲线、土壤溶质运移、土壤优先流、土壤导水率以及地表径流和土壤侵蚀等具有重要影响。研究结果表明,3月份岷江上游干旱河谷0-5cm土层具斥水性的土壤在空间上的分布概率约为34%,其中强度斥水性土壤分布比例为5%;在时间分布上,土壤斥水性主要表现在7月,轻度以下斥水性概率为91%,强度以上斥水性概率为58%;从各粒级土壤斥水性的研究结果来看,斥水性与土壤粒级呈显著负相关,粒级越小,土壤斥水性越高。因此,岷江上游干旱河谷旱地土壤斥水性具有明显的时空分布差异,并且粒级越小土壤斥水性越强,7月份土壤表层的土壤斥水性强度与分布比例高。这可能是导致干旱河谷严重水土流失、土壤砂砾化的一个重要原因。%Soil water repellency is a widespread hydrologic phenomenon in different soils all over the world,and its implications encompass hysteresis of the water retention curve,unstable wetting fronts with fingered flow,reduced infiltration capacity as compared to wettable soils,and accelerated hillslope runoff and erosion.The results show that probability of 0-5 cm layer of soil with slight and strong repellency is about 34% in total,of which soil with strong water repellency is 5% in the dry valley of Minjiang River in March.In July,the probability of soil with slight and strong repellency is 91%,in which 58% is strong water repellent soil.The results also show that soil water repellency is significantly negatively related to the ratio of soil particle size.It can be concluded that there are apparently temporal and spatial variability for soil water repellency and water repellent soil distribution in the dry valley of Minjiang River.A higher ratio of strong soil water repellency exhibits in July of monsoon in topsoil,and in soil with higher proportion of fine fraction,which may be one of

  13. Consolidating and water repellent treatments applied to wet and salt contaminated granite

    Directory of Open Access Journals (Sweden)

    Silva, B.

    2000-03-01

    Full Text Available A comparison was made of the efficacy of two consolidants and two water repellents applied to samples of granite under optimum conditions, with the efficacy of the same products applied to the granite in the presence of soluble salts or water. The amount of product absorbed and the amount of dry polymer remaining after treatment were compared. The results show that the presence of water and soluble salts in the stone significantly modifies the consumption of the products (in particular the water repellents and also the level of dry polymer retained. The water repellents were found to be much less effective when the substrate contained salts, whereas the presence of water did not appear to influence their efficacy. The lack of correlation between uptake, active dry polymer, and efficacy led to the conclusion that the presence of salts or water markedly changes the kinetics of the polymerization of the products.

    Se analiza la eficacia de dos consolidantes y dos hidrofugantes aplicados a rocas graníticas en condiciones óptimas comparativamente a la eficacia de los mismos productos aplicados sobre los mismos sustratos conteniendo cierta cantidad de sales solubles o de agua. Se compara la cantidad de producto absorbido y la cantidad de materia seca presente tras el curado. Los resultados indican que la presencia de agua y de sales solubles en la piedra modifica significativamente el consumo de los productos, sobre todo el de los hidrofugantes, así como la cantidad de materia seca. Se observa, asimismo, un fuerte detrimento en la eficacia de los hidrofugantes cuando el sustrato contiene sales mientras que, al contrario, la presencia de agua no parece infiuir en dicha eficacia. La falta de correlación entre el consumo, materia seca activa y eficacia lleva a concluir que la presencia de sales o agua modifica sensiblemente la cinética de la polimeración de los productos.

  14. Plant Secondary Metabolites as Rodent Repellents: a Systematic Review.

    Science.gov (United States)

    Hansen, Sabine C; Stolter, Caroline; Imholt, Christian; Jacob, Jens

    2016-09-01

    The vast number of plant secondary metabolites (PSMs) produced by higher plants has generated many efforts to exploit their potential for pest control. We performed a systematic literature search to retrieve relevant publications, and we evaluated these according to PSM groups to derive information about the potential for developing plant-derived rodent repellents. We screened a total of 54 publications where different compounds or plants were tested regarding rodent behavior/metabolism. In the search for widely applicable products, we recommend multi-species systematic screening of PSMs, especially from the essential oil and terpenoid group, as laboratory experiments have uniformly shown the strongest effects across species. Other groups of compounds might be more suitable for the management of species-specific or sex-specific issues, as the effects of some compounds on particular rodent target species or sex might not be present in non-target species or in both sexes. Although plant metabolites have potential as a tool for ecologically-based rodent management, this review demonstrates inconsistent success across laboratory, enclosure, and field studies, which ultimately has lead to a small number of currently registered PSM-based rodent repellents.

  15. Laser removal of water repellent treatments on limestone

    Science.gov (United States)

    Gómez-Heras, Miguel; Alvarez de Buergo, Mónica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

    2003-12-01

    Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

  16. Laser removal of water repellent treatments on limestone

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

    2003-12-15

    Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

  17. Comparison of postfire soil water repellency amelioration strategies on bluebunch wheatgrass and cheatgrass survival

    Science.gov (United States)

    Soil water repellency may significantly limit site recovery following wildfire. This study was designed to compare survival and growth of the native plant species bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A. Löve) to the invasive annual weed cheatgrass (Bromus tectorum L.), and to compar...

  18. Soil water repellency within a burned pinon-juniper woodland: spatial distribution, severity, and ecohydrologic implications

    Science.gov (United States)

    Post-fire recovery of juniper-dominated ecosystems is dependent on the extent that ecological processes have been altered. Soil water repellency is a common condition in these ecosystems that may limit site recovery. In this study we examined the extent, severity, and ecohydrologic implications of p...

  19. Phoenix dactylifera L. spathe essential oil: Chemical composition and repellent activity against the yellow fever mosquito

    Science.gov (United States)

    Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dacty...

  20. Water repellency under coniferous and deciduous forest - Experimental assessment and impact on overland flow

    NARCIS (Netherlands)

    Butzen, Verena; Seeger, Manuel; Marruedo, Amaia; Jonge, de Lianne; Wengel, René; Ries, Johannes B.; Casper, Markus C.

    2015-01-01

    Current climate change makes it necessary to gain a deeper understanding of the runoff generation processes in Central European forests. A changing climate might affect soil water repellency (SWR) which can be seen as an import trigger for overland flow generation in forested areas. In this study

  1. DIMENSIONAL STABILITY AND WATER REPELLENT EFFICIENCY MEASUREMENT OF CHEMICALLY MODIFIED TROPICAL LIGHT HARDWOOD

    OpenAIRE

    Md. Saiful Islam; Sinin Hamdan; Mohamad Rusop; Md. Rezaur Rahman; Abu Saleh Ahmed; M. A. M. Mohd Idrus

    2012-01-01

    Chemical modification is an often-followed route to improve physical and mechanical properties of solid wood materials. In this study five kinds of tropical light hardwoods species, namely jelutong (Dyera costulata), terbulan (Endospermum diadenum), batai (Paraserianthes moluccana), rubberwood (Hevea brasiliensis), and pulai (Alstonia pneumatophora), were chemically modified with benzene diazonium salt to improve their dimensional stability and water repellent efficiency. The dimensional stab...

  2. Repellence and toxicity of plant essential oils to the potato aphid, Macrosiphum euphorbiae

    NARCIS (Netherlands)

    Munneke, M.E.; Bruin, de A.; Moskal, J.R.; Tol, van R.W.H.M.

    2004-01-01

    Several plant essential oils were tested for their effect on behaviour and mortality of M. euphorbiae. Olfactory and contact experiments were performed to study these effects. We found that host plant and formulation of the different oils have a strong influence on repellence and mortality of the

  3. Retrospective Study on the Efficacy and Safety of Quinacrine Sterilization

    Institute of Scientific and Technical Information of China (English)

    丁菊红; 陆卫群; 丁婉华; 朱红; 童建孙

    2000-01-01

    Objective To observe and evaluate the efficacy and safety of quinacrine sterilization.Methods A total of 572 cases of quinacrine sterilization preformed during the 4 years from 1993to 1997in Jiangsu and Guizhou Provinces were employed in this study. The efficacy and safety of quinacrine sterilization in those case were studied and evaluated, with 588 cases of surgical sterilization performed at the same time being the control group.Results Both groups were with identical demographic and gynecological characteristics. The result of multiple decrement life table analysis showed the 12th gross cumulative failure rates for quinacrine sterilization was 3. 13% and serious side effects occurred in only 2 cases accounting for O. 35%. One was ectopic pregnancy (20 months after treatment). The other was due to anaphylaxis in 10 minutes after the second insertion). No difference in the liver and nephic functions was detected and no suspected cancer cells or cancer cells were found in the two groups. 99. 6% of the 572 women interviewed accepted the quinacrine sterilization.Conclusions Quinacrine sterilization method is with high acceptability but comparatively low effectiveness. It has been proved to be a safe method of contraception in short-term. However, the safety of long-term still needs further study.

  4. Soil water repellency affects production and transport of CO2 and CH4 in soil

    Science.gov (United States)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  5. Multiple comparisons in drug efficacy studies: scientific or marketing principles?

    Science.gov (United States)

    Leo, Jonathan

    2004-01-01

    When researchers design an experiment to compare a given medication to another medication, a behavioral therapy, or a placebo, the experiment often involves numerous comparisons. For instance, there may be several different evaluation methods, raters, and time points. Although scientifically justified, such comparisons can be abused in the interests of drug marketing. This article provides two recent examples of such questionable practices. The first involves the case of the arthritis drug celecoxib (Celebrex), where the study lasted 12 months but the authors only presented 6 months of data. The second case involves the NIMH Multimodal Treatment Study (MTA) study evaluating the efficacy of stimulant medication for attention-deficit hyperactivity disorder where ratings made by several groups are reported in contradictory fashion. The MTA authors have not clarified the confusion, at least in print, suggesting that the actual findings of the study may have played little role in the authors' reported conclusions.

  6. Larvicidal and mosquito repellent activities of Pine (Pinus longifolia, Family: Pinaceae oil

    Directory of Open Access Journals (Sweden)

    M.A. Ansari, P.K. Mittal, R.K. Razdan & U. Sreehari

    2005-09-01

    Full Text Available Background & objectives: Various plant-based products are safe and biodegradable alternatives tosynthetic chemicals for use against mosquitoes. Oil of Pinus longifolia is traditionally used forprotection against mosquitoes in some rural areas but there is no documented report of its use againstmosquitoes. The present study was undertaken to scientifically evaluate the activity of Pine oilagainst mosquitoes.Methods: The oil was procured from the market and its contents were chemically analysed. Larvicidalactivity of oil was tested in laboratory bioassays, while repellent action was studied during wholenight bait collections in field by direct application on the skin and after its impregnation on mats.Results: Results showed varying degree of larvicidal activity of Pine oil against mosquitoes with LC50values ranging between 82 and 112 ppm. The Pine oil had strong repellent action against mosquitoesas it provided 100% protection against Anopheles culicifacies for 11 h and 97% protection againstCulex quinquefasciatus for nine hours respectively. Electrically heated mats prepared from Pine oilprovided, 94 and 88% protection against An. culicifacies and Cx. quinquefasciatus for 10 and sevenhours respectively.Interpretaion & conclusion: Pine oil is effective against mosquito larvae at very higher doses whichare not of any practical utility. However, Pine oil showed strong repellent action against An. culicifacies(malaria vector and Cx. quinquefasciatus (pest mosquito. Thus its use could be popularised asmosquito repellent.

  7. [The preclinical efficacy of emergency care. A prospective study].

    Science.gov (United States)

    Hennes, H J; Reinhardt, T; Otto, S; Dick, W

    1993-07-01

    Quality assurance has become an important issue in emergency medicine. At present, no prospective studies are available that quantify the efficacy of interventions performed by emergency doctors. The development and implementation of a rapid, yet simple scoring system, allowing preclinical assessment of all emergency medicine patients, is required. Once the scoring system is implemented, evaluation of the prehospital intervention, based upon objective parameters, is possible. METHODS. The Mainz Emergency Evaluation Score (MEES) is based on seven parameters: level of consciousness, heart rate, heart rhythm, arterial blood pressure, respiratory rate, partial arterial oxygen saturation and pain. A coded value is assigned to each parameter, with the normal physiological condition securing a score of 4, while a life-threatening condition receives a value of 1. For the parameter of pain there is no life-threatening condition, so the lowest value allowed is 2 (Table 2). Addition of the respective values from the seven parameters yields the MEES value, which objectively reflects the patients' condition (minimum = 8, maximum = 28). Comparing the MEES value before (MEES1) and after the intervention (MEES2) allows an objective evaluation of the efficacy of the preclinical care (delta-MEES = MEES2-MEES1). A difference of > or = +2 is considered an improvement, +1, +/- 0, -1 are rated as unchanged and rank sum test (Wilcoxon) and the correlation coefficient (Kendall-Tau). RESULTS. In 356 patients the condition of 187 (52%) patients improved during the preclinical treatment; the condition of 156 (44%) patients did not change. In 13 patients (3%) the condition became worse (Table 5, Fig. 2). Allocation to 16 diagnosis groups revealed that the improvement in the patient's condition depended on the underlying disease (Table 3); the disease-specific parameter improved in all cases (Table 7). CONCLUSIONS. With the MEES score one can assess the patient's prehospital condition and

  8. Analysis Study of Survey for Safety and Efficacy of Pharmacopuncture

    Directory of Open Access Journals (Sweden)

    Hong Kwon-eui

    2010-09-01

    Full Text Available This study was done in order to present clinical trial method for safety and efficacy of Pharmacopuncture. The results were summarized as follow:Objective : The purpose of this study is to verify about safety and effectiveness of pharmacopuncture. Methods : We use questionnaire created by expert group. Survey was conducted to target clinicians who using pharmacopuncture more then 5 years. Results & Conclusion : Pharmacopuncture is effective. and that is widely used in the musculoskeletal diseases. but treatment method has not been organized to objectivity. Some pharmacopuncture causes specific symptoms, but no serious side effects. Generally, pharmacopuncture is effective and safety. * This study is performed under the Research and Development Project of Korean Pharmacopuncture Institiute(2010’s sponsorship.

  9. Observations on Snake Repellent Property of Some Plant Extracts

    Directory of Open Access Journals (Sweden)

    D.M. Renapurkar

    1991-01-01

    Full Text Available The repellent property of certain plant extracts and oils against snakes has been investigated. For this purpose 15 hexane extracts of plants and 11 oils were tested in the laboratory in a specially designed cage. Out of the materials tested. Across calamus extract and pine oil were found to exhibit excellent snake repellent property.

  10. Multiple activities of insect repellents on odorant receptors in mosquitoes

    Science.gov (United States)

    Several lines of evidence suggest that insect repellent molecules reduce mosquito-host contacts by interacting with odorants and odorant receptors (ORs) ultimately affecting olfactory-driven behaviors. We describe the molecular effects of ten insect repellents and a pyrethroid insecticide with known...

  11. Water repellency of soils; the influence of ambient relative humidity

    NARCIS (Netherlands)

    Doerr, S.H.; Dekker, L.W.; Ritsema, C.J.; Shakesby, R.A.; Bryant, R.

    2002-01-01

    Adverse effects of soil water repellency (hydrophobicity) are of concern during or following rainfall or irrigation, and are often preceded by conditions of high atmospheric relative humidity (RH). Assessments of repellency are, however, commonly conducted on air-dried samples at ambient laboratory

  12. Repellent activity of five essential oils against Culex pipiens.

    Science.gov (United States)

    Erler, F; Ulug, I; Yalcinkaya, B

    2006-12-01

    Essential oils extracted from the seeds of anise (Pimpinella anisum), dried fruits of eucalyptus (Eucalyptus camaldulensis), dried foliage of mint (Mentha piperita) and basil (Ocimum basilicum) and fresh foliage of laurel (Laurus nobilis) were tested for their repellency against the adult females of Culex pipiens. All essential oils showed repellency in varying degrees, eucalyptus, basil and anise being the most active.

  13. Plant products used as mosquito repellents in Guinea Bissau, West Africa.

    Science.gov (United States)

    Pålsson, K; Jaenson, T G

    1999-01-15

    By standardized interviews of people in 23 rural villages, in the Oio region of Guinea Bissau, we collected data on which plant species and plant derived products or methods people use to reduce mosquito biting activity. The following plants were used to reduce numbers of mosquitoes indoors at night: fresh or smouldering Hyptis suaveolens Poit. (Lamiaceae), smoke of the bark of Daniellia oliveri Rolfe (Caesalpiniaceae), smoke of the infructescence of Elaeis guineensis Jacq. (Arecaceae), smoke of the seed capsules of Parkia biglobosa (Jacq.) Benth. (Mimosaceae), smoke of the leaves of Azadirachta indica A.Juss. (Meliaceae) and Eucalyptus sp. (Myrtaceae), fresh Ocimum canum Sims (Lamiaceae), and fresh Senna occidentalis (L.) Link (Caesalpiniaceae). In two field experiments we estimated the 'repellent activity' of certain of these plants and compared their efficacies with those of two commercially available mosquito repellents, i.e. 'positive' controls. In the first experiment we tested: smouldering H. suaveolens (85.4% repellency); fresh H. suaveolens (73.2%); burning of the bark of D. oliveri (74.7%); and smoke of the leaves of Eucalyptus (72.2%). In the second experiment we tested: smouldering H. suaveolens (83.6% repellency); fresh H. suaveolens (66.5%); burning of the bark of D. oliveri (77.9%); smoke of the leaves of A. indica (76.0%); smoke of the infructescence of E. guineensis (69.0%); fresh O. canum (63.6%); and fresh S. occidentalis; (29.4%). All the products tested, except S. occidentalis were significantly more effective than the negative control.

  14. A novel protein-repellent dental composite containing 2-methacryloyloxyethyl phosphorylcholine.

    Science.gov (United States)

    Zhang, Ning; Chen, Chen; Melo, Mary As; Bai, Yu-Xing; Cheng, Lei; Xu, Hockin Hk

    2015-06-26

    Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure. To date, there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment. The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption, bacteria attachment, biofilm growth, and mechanical properties. Composites were synthesized with 0 (control), 0.75%, 1.5%, 2.25%, 3%, 4.5% and 6% of MPC by mass. A commercial composite was also tested as a control. Mechanical properties were measured in three-point flexure. Protein adsorption onto the composite was determined by the microbicinchoninic acid method. A human saliva microcosm biofilm model was used. Early attachment at 4 h, biofilm at 2 days, live/dead staining and colony-forming units (CFUs) of biofilms grown on the composites were investigated. Composites with MPC of up to 3% had mechanical properties similar to those without MPC and those of the commercial control, whereas 4.5% and 6% MPC decreased the mechanical properties (Prepellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries. The protein-repellent method might be applicable to other dental materials.

  15. Repellent activity of some essential oils against Simulium species in India.

    Science.gov (United States)

    Hazarika, S; Dhiman, Sunil; Rabha, Bipul; Bhola, R K; Singh, Lokendera

    2012-01-01

    Use of repellents seems to be most reliable method of personal protection against annoyance and infections associated with haematophagous insects. We have investigated the biting activity of Simulium and tested the repellency of five essential oils extracted from Homalomena aromatica Schott (Alismatales: Araceae), Pogostemon heyneanus Bentham (Lamiales: Lamiaceae), Citrus aurantifolia Swingle (Sapindales: Rutaceae), Vitex negundo L. (Lamiales: Lamiaceae), and Ageratum conzoides L. (Asterales: Asteraceae) on the human volunteers against Simulium (blackflies) in three locations of Arunachal Pradesh, India. Blackflies preferred biting legs (> 79%) as compared to hand and face with profound biting activity during 1000-1100 h (> 23%) and 1500 - 1600 h (> 28%). The essential oil extracted from Homalomena aromatica, Vitex negundo and Ageratum conizoides provided > 2 h protection at 5% concentration and > 5 h protection at 10% concentration in all the three testing locations. The repellency of Homalomena aromatica, Vitex negundo and Ageratum conizoides essential oils after 6 h application was > 50% at 5% concentration and > 90% at 10% concentration. The study provides evidence for the potential of these essential oils in developing new repellents against blackflies.

  16. Insecticidal and Repellent Activity of Several Plant-Derived Essential Oils Against Aedes aegypti.

    Science.gov (United States)

    Castillo, Ruth M; Stashenko, Elena; Duque, Jonny E

    2017-03-01

    We examined the pupicidal, adulticidal, repellent, and oviposition-deterrent activities of essential oils (EOs) from Lippia alba, L. origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis , Cananga odorata , Swinglea glutinosa, and Tagetes lucida plants against Aedes aegypti under laboratory conditions. Pupicidal and adulticidal activities were assessed at exploratory concentrations of 250, 310, and 390 parts per million (ppm); and 30, 300, and 1,000 ppm, respectively. The greatest pupicidal activity was exhibited at 390 ppm with a 24-h exposure by L. origanoides, and 390 ppm with a 48-h exposure by Citrus sinensis . Lippia origanoides killed all adult mosquitoes at 300 ppm after 120 min of exposure. Only L. origanoides and E. citriodora EOs, applied at 1,000 ppm to human skin, produced the greatest repellency (100%) to host-seeking Ae. aegypti after 2 min of exposure; the repellency decreased between 12% and 10% after 15 min. Complete oviposition deterrence by gravid Ae. aegypti was observed for E. citriodora EOs at 200 ppm with an oviposition activity index of -1.00. These results confirm that the EOs assessed in this study have insecticidal, repellent, and oviposition-deterrent activities against the dengue vector, Ae. aegypti.

  17. Synergistic repellent activity of plant essential oils against Aedes aegypti on rabbit Skin

    Directory of Open Access Journals (Sweden)

    Koech Peter Kiplang'at

    2014-12-01

    Full Text Available Mosquito-borne diseases are the major causes of mortality particularly in tropics. Due to drug and insecticide resistance, personal protection by use of skin repellents has become a common approach of control. The purpose of the study is to determine if synergy exists between Ocimum basilicum, Azadirachta indica and Eucalyptus citriodora oils. Kinga Mosquito repelling Wax® and Vaseline Pure Petroleum Jelly® were included as positive and negative test control respectively. The results showed that Chrysanthemum cinerariefolium extract had no paralytic effect at 0.002% and 0.005% with mean repellency of 81.58 and 85.94 respectively. Similar observation was shown by 10% Azadirachta indica oil and Kinga with a mean repellency 85.79 and 80.53 respectively. Azadirachta indica oil was then reinforced by addition of Sweet basil oil and Lemon eucalyptus oil. A combination that provides complete protection and displayed mosquito paralysis was obtained. The developed formulation can replace Kinga® and alternative to Chrysanthemum cinerariefolium extract.

  18. The efficacy of acupuncture on menopausal symptoms (ACOM study)

    DEFF Research Database (Denmark)

    Lund, Kamma Sundgaard; Brodersen, John; Siersma, Volkert

    2017-01-01

    INTRODUCTION: Around 75% of menopausal women experience hot flushes (HF) and 10-20% of all postmenopausal women find this very distressing. The aim of this study is to evaluate the efficacy of acupuncture on moderate-to-severe menopausal symptoms in general and HF in particular. METHODS: An un...... acupuncturists will be medical doctors educated in acupuncture. The primary outcome is change in HF from baseline to week 6 measured by the HF scale from the MenoScores Questionnaire (MSQ). Secondary outcomes are change in other menopausal symptoms, in particular day and night sweats and menopausal......: In the ACOM study, we explore the potential benefits of acupuncture on moderate-to-severe meno-pausal symptoms. The cross-over design offers the possi-bility of examining the legacy effect of acupuncture. FUNDING: The Idella Foundation, the University of Copenhagen and the Research Foundation of General...

  19. The mysterious multi-modal repellency of DEET

    Science.gov (United States)

    DeGennaro, Matthew

    2015-01-01

    DEET is the most effective insect repellent available and has been widely used for more than half a century. Here, I review what is known about the olfactory and contact mechanisms of DEET repellency. For mosquitoes, DEET has at least two molecular targets: Odorant Receptors (ORs) mediate the effect of DEET at a distance, while unknown chemoreceptors mediate repellency upon contact. Additionally, the ionotropic receptor Ir40a has recently been identified as a putative DEET chemosensor in Drosophila. The mechanism of how DEET manipulates these molecular targets to induce insect avoidance in the vapor phase is also contested. Two hypotheses are the most likely: DEET activates an innate olfactory neural circuit leading to avoidance of hosts (smell and avoid hypothesis) or DEET has no behavioral effect on its own, but instead acts cooperatively with host odors to drive repellency (confusant hypothesis). Resolving this mystery will inform the search for a new generation of insect repellents. PMID:26252744

  20. Preparation and performance study of modified MBPP/water repellent PET oil-absorbing composite material%改性 MBPP/拒水PET复合吸油材料的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    王丹; 崔永珠; 王晓; 吕丽华

    2016-01-01

    The melt-blown polypropylene nonwovens were grafted with BMA by UV grafting to improve the absorbing oil property.The surface of the needle polyester nonwovens was padded by fluorine-free water repellent finishing agent NT-X018 to improve the surface properties of water repellent and lipophilic.A kind of MBPP/PET oil-absorbing composite material was prepared by hot-press bonding to improve the poor state of MBPP for mechanical property.The optimum routes were determined by orthogonal tests respectively for MBPP grafted with BMA and PET finished with water repellent.The performance was compared among MBPP, modified MBPP, PET and modified MBPP/water repellent PET composite material.The results showed the adsorption rate, retention for oil ratio, reusability and mechanical properties of the modified MBPP/water repellent PET oil-absorbing composite material were better than those of others.%利用紫外接枝技术将甲基丙烯酸丁酯( BMA)接枝到熔喷聚丙烯( MBPP)非织造材料中,提高材料亲油性;对涤纶( PET)针刺非织造材料表面浸轧无氟拒水剂NT-X018,使材料表面更加疏水亲油;采用热压黏合法,将改性MBPP非织造材料和拒水PET针刺非织造材料复合,制备改性MBPP/拒水PET复合吸油材料,以改善MBPP非织造材料力学性能较差的现状。分别采用正交试验确定紫外接枝改性MBPP非织造材料及PET针刺非织造材料拒水整理的最佳工艺,并将MBPP非织造材料、改性MBPP非织造材料、PET针刺非织造材料与改性MBPP/拒水PET复合吸油材料进行性能比较,结果表明:改性MBPP/拒水PET复合吸油材料吸附率与保油率、重复使用性能及力学性能都有较大的提高。

  1. DEET (N,N-diethyl-meta-toluamide)/PMD (para-menthane-3,8-diol) repellent-treated mesh increases Culicoides catches in light traps.

    Science.gov (United States)

    Murchie, A K; Clawson, S; Rea, I; Forsythe, I W N; Gordon, A W; Jess, S

    2016-09-01

    Biting midges (Culicoides spp.) are vectors of bluetongue and Schmallenberg viruses. Treatment of mesh barriers is a common method for preventing insect-vectored diseases and has been proposed as a means of limiting Culicoides ingression into buildings or livestock transporters. Assessments using animals are costly, logistically difficult and subject to ethical approval. Therefore, initial screening of test repellents/insecticides was made by applying treatments to mesh (2 mm) cages surrounding Onderstepoort light traps. Five commercial treatments were applied to cages as per manufacturers' application rates: control (water), bendiocarb, DEET/p-menthane-3,8-diol (PMD) repellent, Flygo (a terpenoid based repellent) and lambda-cyhalothrin. The experimental design was a 5 × 5 Latin square, replicated in time and repeated twice. Incongruously, the traps surrounded by DEET/PMD repellent-treated mesh caught three to four times more Obsoletus group Culicoides (the commonest midge group) than the other treatments. A proposed hypothesis is that Obsoletus group Culicoides are showing a dose response to DEET/PMD, being attracted at low concentrations and repelled at higher concentrations but that the strong light attraction from the Onderstepoort trap was sufficient to overcome close-range repellence. This study does not imply that DEET/PMD is an ineffective repellent for Culicoides midges in the presence of an animal but rather that caution should be applied to the interpretation of light trap bioassays.

  2. Clinical Self-Efficacy in Senior Nursing Students: A Mixed- Methods Study

    OpenAIRE

    Abdal; Masoudi Alavi; Adib-Hajbaghery

    2015-01-01

    Background Clinical education has a basic role in nursing education, and effective clinical training establishes a sense of clinical self-efficacy in senior nursing students. Self-efficacy is a key component for acting independently in the nursing profession. Objectives This study was designed to outline senior nursing students’ views about clinical self-efficacy and to determine its level in nursing students. ...

  3. An Empirical Study to Determine The Relationship between Occupational Self-Efficacy and Organizational Silence

    OpenAIRE

    Cem KAHYA

    2015-01-01

    The concept of occupational self-efficacy means the efficacy perceptions of employees in their occupational fields, and the concept of organizational silence means the employees avoid to voice their ideas and suggestions about organizational issues. The main aim of this study is to examine the relationship between the concepts of occupational self-efficacy and organizational silence by revealing employees’ perceptions of occupational self-efficacy and organizational silence level. With this a...

  4. Self-efficacy beliefs of university students: an empirical study on the specificity of the construct

    OpenAIRE

    Blanco Blanco, Ángeles

    2010-01-01

    This study tested two propositions of the Social Cognitive Theory in an academic setting: a) Self-efficacy is a domain- specific competence belief; b) Domain-specific selfefficacy is related, but distinct from, other self-evaluation constructs. Participants (272 Spanish university students) completed measures of general self-efficacy, academic self-efficacy, statistics self-efficacy and attitudes towards statistics (cognitive and affective components). Principal Components Analyses and Confir...

  5. Impact of Simulation and Clinical Experience on Self-efficacy in Nursing Students: Intervention Study.

    Science.gov (United States)

    Kimhi, Einat; Reishtein, Judith L; Cohen, Miri; Friger, Michael; Hurvitz, Nancy; Avraham, Rinat

    2016-01-01

    This study compared the effect of simulation and clinical experience timing on self-confidence/self-efficacy for the nursing process. Using a randomized, double-crossover design, self-efficacy was measured 3 times. Although self-efficacy was significantly higher at time 1 for students who had clinical experience, there was no difference between the groups at the end of the course (time 2). Thus, simulation increased self-confidence/self-efficacy equivalently if placed either before or after clinical experience.

  6. Insecticidal Activity and Insect Repellency of Four Species of Sea Lily (Comatulida: Comatulidae) From Taiwan.

    Science.gov (United States)

    Su, Shih-Wei; Lee, Tse-Min; Mok, Hin-Kiu; Chio, Eddie Hang

    2016-01-01

    The methanol and ethyl acetate (EA) extracts of four species of sea lily (Himerometra magnipinna, Comaster multifidus, Comanthina sp., and Comatella maculata) were evaluated for their insecticidal activity against Yellow-fever mosquito larvae (Aedes aegypti) and their repellency against adult Asian Tiger mosquitoes (Aedes albopictus). The 24-hr minimum inhibition concentration (MIC) data revealed that the extracts from H. magnipinna and the C. maculata were the most active, killing mosquito larvae at 12.5 ppm. The toxicity of the extracts from these four sea lilies in descending order was H. magnipinna (12.5 ppm), C. maculata (12.5 ppm), C. multifidus (100 ppm), and Comanthina sp. (200 ppm). Furthermore, no significant difference in toxicity was found using either EA or methanol as the extraction solvent. The MIC at 12.5 ppm is promising as an insecticide lead. The repellency study results show that EA is a better solvent for one species (H. magnipinna), but the methanol is a better solvent overall. The repellency of these sea lily extracts in descending order was Comanthina sp. MeOH (ED50 at 0.32%), followed by H. magnipinna EA (ED50 at 0.38%), C. multifidus MeOH (ED50 at 0.57%), C. maculata MeOH (ED50 at 0.76%), C. multifidus EA (ED50 at 1.25%), and H. magnipinna MeOH (ED50 at 1.67%). A compound with ED50 repellant. Among the studied sea lilies, both Comanthina sp. and H. magnipinna have potential to be further developed as mosquito control agents due to their favorable toxicity and repellency.

  7. Water Repellency, Infiltration and Water Retention Properties of Forest Soils Under Different Management Practices

    Science.gov (United States)

    Wahl, N. A.; Bens, O.; Schäfer, B.; Hüttl, R. F.

    For soils under both agricultural and forest use, management and tillage practice can have significant influence on the hydraulic properties. It is therefore supposed, that management practices are capable of altering surface runoff, water retention and flood- ing risk for river catchments. Soil water repellency (hydrophobicity) can adversely affect soil hydrological properties, e.g. reduce infiltration capacity and induce pref- erential flow, thus enhancing the overall risk of flooding in river catchment areas. Hydrophobic effects are especially pronounced in coniferous forest soils. Investigations were carried out on several study plots in the German Northeastern Lowlands, located app. 50 km NE of Berlin in Brandenburg. Soils found in the area are mainly of glacifluvial origin with a pronounced sandy texture (with medium sized sand dominating). The four stands investigated represent different stages of forest transfor- mation, in a sense of a SfalseT chronosequence and are made up of populations of & cedil;Pinus sylvestris and Fagus sylvatica of different ages. Infiltration was measured with hood infiltrometers, and single infiltration rings at soil surface. Water retention capacity and the influence of soil organic matter on water storage were evaluated with laboratory methods. Water repellency was quantified with the water drop penetration time (WDPT) test, for determining the persistence of water repellency, and the ethanol percentage (EP) test, for measuring the severity/degree of water repellency. Soil samples from the four forest plots and different soil depths (0U160 cm) were used for the measurements. SPotentialT water repellencies were & cedil;determined after 3-day oven-drying at 45 C. The results indicate that for sandy forest soils, the overall infiltration capacity of the plots is low due to the effects of water repellency. The inter-variability of the plots is mainly caused by changes in the textural composition of the soils. For all plots a

  8. Water repellency induced by pulmonary surfactants.

    Science.gov (United States)

    Hills, B A

    1982-04-01

    1. Pure cotton fabric was partially carboxylated to produce a tough, porous, hydrophilic sub-phase to stimulate the epithelial membrane of the alveolar wall from a permeability standpoint. 2. Two of the predominant pulmonary surfactants, dipalmitoyl lecithin (DPL) and dipalmitoyl phosphatidylethanolamine (DPPE), were found to inhibit wetting of this synthetic membrane and of human cutaneous epithelium as manifest by a large contact angle. 3. When treated with DPL at physiological concentrations, the porous synthetic membrane was found to support a head of saline well in excess of systolic pulmonary artery pressure with no penetration and could do so for periods well in excess of 1 hr; untreated control samples allowed almost immediate fluid filtration. 4. Filtration could be initiated in the DPL-treated membranes by wetting the reverse side, confirming that the threshold pressure for fluid penetration was afforded by capillarity and, hence, by water repellency induced by the surfactant. 5. Water repellency induced by the amphoteric surfactants occurring naturally in the lung is discussed as a possible factor contributing to the pressure threshold to be exceeded for alveolar oedema to form. 6. Evidence is reviewed and several advantages discussed for the implied concept of an essentially dry lining to the alveolus with a discontinuous liquid layer largely confined to convex corners which could slowly resolve any oedema by surface forces.

  9. Larvicidal and repellent effect of some Tribulus terrestris L., (Zygophyllaceae extracts against the dengue fever mosquito, Aedes aegypti (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Tarek M.Y. El-Sheikh

    2016-01-01

    Full Text Available Aedes aegypti transmits etiologic agents of yellow fever and dengue. Vaccine for dengue virus is not available and vector control is essential to minimize dengue incidence. The larvicidal and repellent effect of the crude ethanol, acetone and petroleum ether extract leaves of Tribulus terrestris, against 3rd instar larvae and adults of mosquito, Ae. aegypti the vector of dengue fever was evaluated. The efficacy of petroleum ether extract seemed to be more effective with LC50 64.6 ppm followed by acetone extract with LC50 173.2 ppm and finally ethanolic extract with LC50 376.4 ppm. Moreover, the acetone and petroleum ether extracts exerted a highly delayed toxic effect on the pupae and adults resulted from treated larvae, where the pupal mortality was 57.1% and 100% at concentrations 400 and 100 ppm, respectively. Also, the petroleum ether and acetone extracts showed reduction effects on adult emergence. The repellent action of the plant extracts tested was varied depending on the solvent used in extraction and the dose of the extract. The most effective plant extract that evoked 100% repellency or biting deterrence was petroleum ether extract at a dose of 1.5 mg/cm2 compared with 100% repellency for commercial formulation, N,N-diethyl-3-methylbenzamide (DEET at the same dose. Hence, these extracts can be used as an effective alternative to the existing synthetic pesticides for the control of Ae. aegypti.

  10. The efficacy of acupuncture on menopausal symptoms (ACOM study)

    DEFF Research Database (Denmark)

    Lund, Kamma Sundgaard; Brodersen, John; Siersma, Volkert

    2017-01-01

    INTRODUCTION: Around 75% of menopausal women experience hot flushes (HF) and 10-20% of all postmenopausal women find this very distressing. The aim of this study is to evaluate the efficacy of acupuncture on moderate-to-severe menopausal symptoms in general and HF in particular. METHODS: An un......-blinded randomised trial (cross-over) with 1:1 allocation to early (intervention) versus late (control) acupuncture. The included women suffer from moderate-to-severe HF and will receive a weekly treatment during five consecutive weeks in the following predefined acupuncture points: CV-3, CV-4, LR-8, SP-6, SP-9. All...... acupuncturists will be medical doctors educated in acupuncture. The primary outcome is change in HF from baseline to week 6 measured by the HF scale from the MenoScores Questionnaire (MSQ). Secondary outcomes are change in other menopausal symptoms, in particular day and night sweats and menopausal...

  11. The efficacy of acupuncture on menopausal symptoms (ACOM study)

    DEFF Research Database (Denmark)

    Brodersen, John; Siersma, Volkert; Waldorff, Frans Boch

    2017-01-01

    INTRODUCTION: Around 75% of menopausal women experience hot flushes (HF) and 10-20% of all postmenopausal women find this very distressing. The aim of this study is to evaluate the efficacy of acupuncture on moderate-to-severe menopausal symptoms in general and HF in particular. METHODS: An un......-blinded randomised trial (cross-over) with 1:1 allocation to early (intervention) versus late (control) acupuncture. The included women suffer from moderate-to-severe HF and will receive a weekly treatment during five consecutive weeks in the following predefined acupuncture points: CV-3, CV-4, LR-8, SP-6, SP-9. All...... acupuncturists will be medical doctors educated in acupuncture. The primary outcome is change in HF from baseline to week 6 measured by the HF scale from the MenoScores Questionnaire (MSQ). Secondary outcomes are change in other menopausal symptoms, in particular day and night sweats and menopausal...

  12. Mosquito adulticidal and repellent activities of botanical extracts against malarial vector,Anopheles stephensi Liston (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan; Rajamohan Sivakumar

    2011-01-01

    Objective:To determine the adulticidal and repellent activities of different solvent leaf extracts ofEclipta alba (E. alba) andAndrographis paniculata (A. paniculata)against malarial vector, Anopheles stephensi (An. stephensi).Methods:Adulticidal efficacy of the crude leaf extracts ofE. alba andA. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the five to six day old adult female mosquitoes of An. stephensi. The adult mortality was observed after24 h under the laboratory conditions. The repellent efficacy was determined againstAn. stephensimosquito species at three concentrations viz.,1.0, 2.5 and 5.0 mg/cm2 under laboratory conditions.Results: Among the tested solvents the maximum efficacy was observed in the methanol extract. TheLC50 andLC90 values ofE. alba andA. paniculata against adults ofAn. stephensiwere150.36, 130.19 ppm and285.22, 244.16ppm, respectively. No mortality was observed in controls. Thechi-square values were significant at P<0.05 level. Methanol extract of E. alba andA. paniculata was produce maximum repellency againstAn. stephensi.Conclusions:From the results it can be concluded the crude extract ofE. alba andA. paniculatawas an excellent potential for controllingAn. stephensimosquitoes.

  13. Interacting tilt and kink instabilities in repelling current channels

    CERN Document Server

    Keppens, Rony; Xia, Chun

    2014-01-01

    We present a numerical study in resistive magnetohydrodynamics where the initial equilibrium configuration contains adjacent, oppositely directed, parallel current channels. Since oppositely directed current channels repel, the equilibrium is liable to an ideal magnetohydrodynamic tilt instability. This tilt evolution, previously studied in planar settings, involves two magnetic islands or fluxropes, which on Alfvenic timescales undergo a combined rotation and separation. This in turn leads to the creation of (near) singular current layers, posing severe challenges to numerical approaches. Using our open-source grid-adaptive MPI-AMRVAC software, we revisit the planar evolution case in compressible MHD, as well as its extension to 2.5D and full 3D scenarios. As long as the third dimension remains ignorable, pure tilt evolutions result which are hardly affected by out of plane magnetic field components. In all 2.5D runs, our simulations do show secondary tearing type disruptions throughout the near singular cur...

  14. Efficacy of chlorpyrifos and fipronil in relation to soil depths against subterranean termites

    Directory of Open Access Journals (Sweden)

    S. Ahmed

    2017-04-01

    Full Text Available The present studies aimed at finding the best concentration of chlorpyrifos and fipronil following mixing with the same and different soil depths in laboratory and field trials. Barrier efficacy of these insecticides was measured by determining wood weight loss kept as bait on the treated soils in the field experiment and length of galleries in the laboratory experiments. Results showed that termites were able to penetrate galleries treated with both insecticides at variable distances. Length of gallery and repellence was concentration dependent. Five percent concentration of both insecticides at 45 cm was the best treatment in comparison with other combination of concentration and soil depths. Maximum gallery length and repellence was observed after the application of chlorpyrifos in comparison with fipronil. Fipronil applied at different concentrations following mixing with the same and with different soil depths was the best treatment as a standard pre-construction step.

  15. The influence of compost addition on the water repellency of brownfield soils

    Science.gov (United States)

    Whelan, Amii; Kechavarzi, Cedric; Sakrabani, Ruben; Coulon, Frederic; Simmons, Robert; Wu, Guozhong

    2010-05-01

    also tested. The results show that the water repellency of air dried samples is significantly higher in samples amended with composts and increases with increasing organic matter content. The WDPT suggests that compost, when dry, is hydrophobic. Diesel contamination leads to a decrease in sorptivity compared to uncontaminated controls and wettability is not re-established following the addition of compost. Finally, the increase in compost volume (i.e. application rate) in the field samples leads to an increase in water repellency. The infiltration tests, carried out using a miniature tension infiltrometer, also illustrate different effects of hydrophobicity on infiltration, with some samples demonstrating reduced infiltration and low sorptivity but others showing no infiltration at all until the breakdown of repellency at later times. This investigation is currently being complemented by a study of the influence of hydrophobic organic contaminant sequestration with time (i.e. ageing), estimated by measuring the changes in the available fraction of polycyclic aromatic hydrocarbons (PAHs), on the water repellency of compost amended brownfield soils.

  16. 土壤疏水性研究进展%Research Progress in Soil Water Repellency

    Institute of Scientific and Technical Information of China (English)

    赵利坤; 秦纪洪; 孙辉

    2011-01-01

    土壤疏水性是指水分不能或很难湿润土壤颗粒表面的物理现象.土壤疏水性研究不仅有助于合理评价疏水性对生态环境的形响,而且能为当前水土流失问题的解决提供新思路.本文对国内外土壤硫水性研究现状进行总结.着重阐述了土壤疏水性及产生机理、影响因素、测定方法及水文效应,并结合存在问题展望未来的研究,以期为我国开展相关研究提供参考.%Soil water repellency is the hydrophobic property of soil which indicates the physical phenomenon that the surface of soil particles can not or hard to be moistened by soil water. Study on soil water repellency is not only helpful to assessing the impact of hydrophobic property of soils on ecological environment but also heneficial to providing soil erosion control with new approaches. The paper summarized the latest status on the researches in soil water repellency at home and abroad, mainly introduced the soil water repellency, mechanisms, determining methods and hydrological effect,and direction for the soil water repellency were advanced based on the existing problem. Then the strategies and suggestions were put forward in the end in order to research in China.

  17. A 4-alkyl-substituted analogue of guaiacol shows greater repellency to savannah tsetse (Glossina spp.).

    Science.gov (United States)

    Saini, Rajindar K; Hassanali, Ahmed

    2007-05-01

    The responses of Glossina morsitans morsitans Westwood to guaiacol (2-methoxyphenol), a mild repellent constituent of bovid odors, and seven analogues comprising 2-methoxyfuran, 2,4-dimethylphenol, 2-methoxy-4-methylphenol (4-methylguaiacol), 4-ethyl-2-methoxyphenol (4-ethylguaiacol), 4-allyl-2-methoxyphenol (4-allylguaiacol; eugenol), 3,4-methylenedioxytoluene, and 3,4-dimethoxystyrene were compared in a two-choice wind tunnel. The 4-methyl-substituted derivative (2-methoxy-4-methylphenol) was found to elicit stronger repellent responses from the flies compared with guaiacol. None of the other analogues showed significant repellent effects on flies. 4-Methylguaiacol, guaiacol, and eugenol (which was included because of previous reports of its repellency against a number of arthropods) were further evaluated in the field with wild populations of predominantly Glossina pallidipes Austen. The presence of guaiacol or eugenol near odor-baited traps caused some nonsignificant reduction in the number of tsetse catches at relatively high release rates (approximately 50 mg/hr). In contrast, the 4-methyl derivative at three different release rates (2.2, 4.5, and 9.0 mg/hr) reduced trap catches of baited traps in a dose-response manner. At 10 mg/hr release rate, it reduced the catches of baited and unbaited traps by approximately 80 and approximately 70%, respectively. In addition, the compound not only reduced the number of tsetse attracted to natural ox odor (approximately 80%), but also had an effect on their feeding responses, reducing the proportion that fed on an ox by more than 80%. Our study shows that the presence of a methyl substituent at the 4-position of guaiacol enhances the repellency of the molecule to savannah tsetse and suggests that 4-methylguaiacol may represent a promising additional tool in the arsenal of techniques in trypanosomiasis control.

  18. A novel protein-repellent dental composite containing 2-methacryloyloxyethyl phosphorylcholine

    Institute of Scientific and Technical Information of China (English)

    Ning Zhang; Chen Chen; Mary AS Melo; Yu-Xing Bai; Lei Cheng; Hockin HK Xu

    2015-01-01

    Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure. To date, there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment. The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption, bacteria attachment, biofilm growth, and mechanical properties. Composites were synthesized with 0 (control), 0.75%, 1.5%, 2.25%, 3%, 4.5%and 6%of MPC by mass. A commercial composite was also tested as a control. Mechanical properties were measured in three-point flexure. Protein adsorption onto the composite was determined by the microbicinchoninic acid method. A human saliva microcosm biofilm model was used. Early attachment at 4 h, biofilm at 2 days, live/dead staining and colony-forming units (CFUs) of biofilms grown on the composites were investigated. Composites with MPC of up to 3%had mechanical properties similar to those without MPC and those of the commercial control, whereas 4.5%and 6%MPC decreased the mechanical properties (P,0.05). Increasing MPC from 0 to 3%reduced the protein adsorption on composites (P,0.05). The composite with 3%MPC had protein adsorption that was 1/12 that of the control (P,0.05). Oral bacteria early attachment and biofilm growth were also greatly reduced on the composite with 3%MPC, compared to the control (P,0.05). In conclusion, incorporation of MPC into composites at 3%greatly reduced protein adsorption, bacteria attachment and biofilm CFUs, without compromising mechanical properties. Protein-repellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries. The protein-repellent method might be applicable to other dental materials.

  19. Evaluation of herbal essential oil as repellents against Aedes aegypti (L.) and Anopheles dirus Peyton & Harrion

    Institute of Scientific and Technical Information of China (English)

    Duangkamon Sritabutra; Mayura Soonwera; Sirirat Waltanachanobon; Supaporn Poungjai

    2011-01-01

    Objective: To investigate the repellent activity of herbal essential oils from garlic (Allium sativum), clove (Syzygium aromaticum), lemon grass (Cybopogon citratus), citronella grass (Cymbopogon nardus), peppermint (Mentha piperita), eucalyptus (Eucalyptus globulus), orange (Citrus sinensis) and sweet basil (Ocimum basilicum) and their combinations against Aedes aegypti (Ae. aegypti) (L.) and Anopheles dirus (An. dirus) Peyton & Harrion under laboratory conditions.Methods:In laboratory condition, 0.1 mL of each essential oil was applied to 3-10 cm of exposed area on a volunteer’s forearm. The test was carried out every 30 min until fewer than two mosquitoes bit or land during the 3 min study period and then the repellency test was stopped.Results:Essential oil from lemon grass exhibited protection against biting from two mosquito species, for Ae. aegypti [(98.66±11.56) min protection time and 0.97% biting rate] and for An. dirus [(98.00±15.28) min protection time and 0.80% biting rate]. The combinations from eucalyptus oil and sweet basil oil were effective as repellents and feeding deterrents against Ae. aegypti [(98.87±10.28) min protection time and 0.90% biting rate] and An. dirus [(210±10.70) min protection time and 0.93% biting rate]. All herbal repellents exhibited the period of protection time against Ae. aegypti which was lower than 120 min. Conlussions: It can be concluded that oils of lemon grass and combination from eucalyptus-sweet basil are the most effective in repellent activity.

  20. Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle

    Science.gov (United States)

    Fuerstenau, D. W.; Huang, P.; Ravikumar, R.

    1997-01-01

    The objective of this research was two-fold: first, to identify and test inorganic water-repellent materials that would be hydrophobic even after thermal cycling to temperatures above 600 C and, second, to develop a model that would link hydrophobicity of a material to the chemical properties of its constituent atoms. Four different materials were selected for detailed experimental study, namely, boron nitride, talc, molybdenite, and pyrophyllite, all of which have a layered structure made up of ionic/covalent bonds within the layers but with van der Waals bonds between the layers. The materials tested could be considered hydrophobic for a nonporous surface but none of the observed contact angles exceeded the necessary 90 degrees required for water repellency of porous materials. Boron nitride and talc were observed to retain their water-repellency when heated in air to temperatures that did not exceed 800 C, and molybdenite was found to be retain its hydrophobicity when heated to temperatures up to 600 C. For these three materials, oxidation and decomposition were identified to be the main cause for the breakdown of water repellency after repeated thermal cycling. Pyrophyllite shows the maximum promise as a potential water-repellent inorganic material, which, when treated initially at 900 C, retained its shape and remained hydrophobic for two thermal cycles where the maximum retreatment temperature is 900 C. A model was developed for predicting materials that might exhibit hydrophobicity by linking two chemical properties, namely, that the constituent ions of the compound belong to the soft acid-base category and that the fractional ionic character of the bonds be less than about 20 percent.

  1. Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence

    NARCIS (Netherlands)

    Ziogas, A.K.; Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Many soils may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency often leads to the development of unstable

  2. Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence

    NARCIS (Netherlands)

    Ziogas, A.K.; Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Many soils may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency often leads to the development of unstable

  3. Correlation between chemical structure and rodent repellency of benzoic acid derivatives

    Science.gov (United States)

    Fearn, J.E.; DeWitt, J.B.

    1965-01-01

    Sixty-five benzoic acid derivatives were either prepared or obtained from commercial concerns, tested for rat repellency, and their indices of repellency computed. The data from these tests were considered analytically for any correlation between chemical structure and rat repellency. The results suggest a qualitative relationship which is useful in deciding probability of repellency in other compounds.

  4. Repellence of plant essential oils to Dermanyssus gallinae and toxicity to the non-target invertebrate Tenebrio molitor.

    Science.gov (United States)

    George, D R; Sparagano, O A E; Port, G; Okello, E; Shiel, R S; Guy, J H

    2009-05-26

    With changes in legislation and consumer demand, alternatives to synthetic acaricides to manage the poultry red mite Dermanyssus gallinae (De Geer) in laying hen flocks are increasingly needed. These mites may cause losses in egg production, anaemia and even death of hens. It may be possible to use plant-derived products as D. gallinae repellents, especially if such products have a minimal impact on non-target organisms. An experiment was conducted with D. gallinae to assess the repellence of a range of plant essential oils, previously found to be of varying toxicity (relatively highly toxic to non-toxic) to this pest. Experiments were also undertaken to assess the toxicity of these products to mealworm beetles (Tenebrio molitor L.), a non-target invertebrate typical of poultry production systems. Results showed that all seven essential oils tested (manuka, thyme, palmarosa, caraway, spearmint, black pepper and juniper leaf) were repellent to D. gallinae at 0.14mg oil/cm(3) (initial concentration) during the first 2 days of study. Thyme essential oil appeared to be the most effective, where repellence lasted until the end of the study period (13 days). At the same concentration toxicity to T. molitor differed, with essential oils of palmarosa and manuka being no more toxic to adult beetles than the control. There was neither a significant association between the rank toxicity and repellence of oils to D. gallinae, nor the toxicity of oils to D. gallinae (as previously determined) and T. molitor.

  5. POLY(N-VINYLPYRROLIDONE)-MODIFIED SURFACES REPEL PLASMA PROTEIN ADSORPTION

    Institute of Scientific and Technical Information of China (English)

    Xiao-li Liu; Zhao-qiang Wu; Dan Li; Hong Chen

    2012-01-01

    The present work aimed to study the interaction between plasma proteins and PVP-modified surfaces under more complex protein conditions.In the competitive adsorption of fibrinogen (Fg) and human serum albumin (HSA),the modified surfaces showed preferential adsorption of HSA.In 100% plasma,the amount of Fg adsorbed onto PVP-modified surfaces was as low as 10 ng/cm2,suggesting the excellent protein resistance properties of the modified surfaces.In addition,immunoblots of proteins eluted from the modified surfaces after plasma contact confirmed that PVP-modified surfaces can repel most plasma proteins,especially proteins that play important roles in the process of blood coagulation.

  6. Engineering water repellency in granular materials for ground applications

    Science.gov (United States)

    Lourenco, Sergio; Saulick, Yunesh; Zheng, Shuang; Kang, Hengyi; Liu, Deyun; Lin, Hongjie

    2017-04-01

    Synthetic water repellent granular materials are a novel technology for constructing water-tight barriers and fills that is both inexpensive and reliant on an abundant local resource - soils. Our research is verifying its stability, so that perceived risks to practical implementation are identified and alleviated. Current ground stabilization measures are intrusive and use concrete, steel, and glass fibres as reinforcement elements (e.g. soil nails), so more sustainable approaches that require fewer raw materials are strongly recommended. Synthetic water repellent granular materials, with persistent water repellency, have been tested for water harvesting and proposed as landfill and slope covers. By chemically, physically and biologically adjusting the magnitude of water repellency, they offer the unique advantage of controlling water infiltration and allow their deployment as semi-permeable or impermeable materials. Other advantages include (1) volumetric stability, (2) high air permeability and low water permeability, (3) suitability for flexible applications (permanent and temporary usage), (4) improved adhesion aggregate-bitumen in pavements. Application areas include hydraulic barriers (e.g. for engineered slopes and waste containment), pavements and other waterproofing systems. Chemical treatments to achieve water repellency include the use of waxes, oils and silicone polymers which affect the soil particles at sub-millimetric scales. To date, our research has been aimed at demonstrating their use as slope covers and establishing the chemical compounds that develop high and stable water repellency. Future work will determine the durability of the water repellent coatings and the mechanics and modelling of processes in such soils.

  7. Neurophysiological Study of Vector Responses to Repellents.

    Science.gov (United States)

    1980-08-01

    E. A., and Chapman R. F. (1972) The control of changes in peripheral sensilla associated with feeding in Locusta migratoria (L.). J. exp. Biol. 57...sensitive to 4-methyl-hexanoic acid’ in Locusta migratoria . Receptors on the other neuron did, however, differentiate between the C-)- and (+)-enantiomers of...Bernars and haij ( 19 72) reported that a substance f rom the corpora cardiaca o t rec-,nt I f ed Locusta Mi.&ratoria acts d irect ly an the

  8. Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control.

    Science.gov (United States)

    Balaji, A P B; Mishra, Prabhakar; Suresh Kumar, R S; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2015-04-01

    The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74 nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48 h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416 mg/L for Bulk DEPA and 0.052 mg/L for Nano DEPA, respectively. The median knockdown concentrations (60 min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage.

  9. Interacting tilt and kink instabilities in repelling current channels

    Energy Technology Data Exchange (ETDEWEB)

    Keppens, R.; Porth, O.; Xia, C., E-mail: rony.keppens@wis.kuleuven.be [Centre for mathematical Plasma-Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2014-11-01

    We present a numerical study in resistive magnetohydrodynamics (MHD) where the initial equilibrium configuration contains adjacent, oppositely directed, parallel current channels. Since oppositely directed current channels repel, the equilibrium is liable to an ideal magnetohydrodynamic tilt instability. This tilt evolution, previously studied in planar settings, involves two magnetic islands or flux ropes, which on Alfvénic timescales undergo a combined rotation and separation. This in turn leads to the creation of (near) singular current layers, posing severe challenges to numerical approaches. Using our open-source grid-adaptive MPI-AMRVAC software, we revisit the planar evolution case in compressible MHD, as well as its extension to two-and-a-half-dimensional (2.5D) and full three-dimensional (3D) scenarios. As long as the third dimension can be ignored, pure tilt evolutions result that are hardly affected by out of plane magnetic field components. In all 2.5D runs, our simulations do show secondary tearing type disruptions throughout the near singular current sheets in the far nonlinear saturation regime. In full 3D runs, both current channels can be liable to additional ideal kink deformations. We discuss the effects of having both tilt and kink instabilities acting simultaneously in the violent, reconnection-dominated evolution. In 3D, both the tilt and the kink instabilities can be stabilized by tension forces. As a concrete space plasma application, we argue that interacting tilt-kink instabilities in repelling current channels provide a novel route to initiate solar coronal mass ejections, distinctly different from the currently favored pure kink or torus instability routes.

  10. Gender fairness in self-efficacy? A Rasch-based validity study of the General Academic Self-efficacy scale (GASE)

    DEFF Research Database (Denmark)

    Nielsen, Tine; Dammeyer, Jesper; Vang, Maria Louison

    2017-01-01

    Studies have reported gender differences in academic self-efficacy. However, how and if academic self-efficacy questionnaires are gender-biased has not been psychometrically investigated. The psychometric properties of a general version of The Physics Self-Efficacy Questionnaire – the General Aca...

  11. Antimicrobial efficacy of commercially available mouthrinses: An in vitro study

    Directory of Open Access Journals (Sweden)

    Roopavathi Kallahalli Mruthyuenjaya

    2016-01-01

    Full Text Available Introduction: Oral cavity ecosystem represents a dynamic pattern. An effective plaque control measure should target plaque formation before the mature plaque is formed. Various types of chemotherapeutic agents are coming up with different antimicrobial agents in them. Hence, this study has been undertaken to know whether these antimicrobial agents are effective on common microorganisms of oral cavity which directly and indirectly contributes to plaque formation Aim: The aim of this study was to determine antimicrobial efficacy of different mouthrinses against the oral pathogens in vitro. Materials and Methods: A total of seven mouthrinses were tested for their antimicrobial activity against three oral pathogens, namely, Streptococcus mutans (MTCC 890, Escherichia coli (ATCC 25922, and Candida albicans (ATCC 10231 by well agar diffusion assay. Statistical analysis was performed using Kruskal–Wallis test. The level of significance used was P< 0.05. Results: Mouthrinse with chlorhexidine (CHX gluconate, triclosan as main ingredients showed maximum zone of inhibition (P = 0.003 against streptococcal mutans and E. coli at 1:16 dilution and mouthrinse with CHX gluconate and zinc chloride showed maximum zone of inhibition at 1:16 dilution against Candida among seven mouthrinses used in the present study. It was also observed that zone of inhibition of all the mouthrinses decreased with the increase in dilution. Conclusion: Among mouthrinses formulations, CHX combined with other active ingredients was found to be more effective.

  12. Plaque removal efficacy of Colgate 360 toothbrush: A clinical study

    Science.gov (United States)

    Iyer, Nageshwar; Chandna, Shalu; Dhindsa, Abhishek; Damle, Dhanashree; Loomba, Ashish

    2016-01-01

    Aim: The aim of this clinical study was to confirm the plaque removal efficacy of the Colgate 360 Whole Mouth Clean Toothbrush. Study Design: This was a single-center, monadic, case–controlled study with the 7 days duration. Materials and Methods: A total of eighty participants (56 male and 24 female) aged between 18 and 45 years with a minimum of 20 permanent teeth (excluding the third molars) without any prosthetic crowns and an initial plaque score of minimum 1.5 as determined by Modified Quigley-Hein Plaque Index (1970) participated in the study. There were two dropouts during the study duration, one male and one female. The participants were instructed to brush for 1 min, after which plaque index was recorded again. They were then instructed to brush their teeth twice a day for 1 min with the assigned toothbrush (Colgate 360 Whole Mouth Clean Toothbrush) and a commercially available fluoride toothpaste for the next 7 days. On the 7th day, all the participants were recalled for follow-up and plaque examination. The plaque index scores (pre- and post-brushing) were recorded, tabulated, and analyzed statistically. Results: The mean plaque indices reduced after brushing both on day 1 and day 7. There was also a reduction in mean plaque indices from day 1 to day 7. All these reductions were statistically significant (P < 0.001). The reduction in plaque scores was independent of the gender of the participants however female participants showed lower scores as compared to male participants (P < 0.001). Conclusion: The present study demonstrated a significant reduction in plaque scores with the use of Colgate 360 Whole Mouth Clean Soft Toothbrush throughout the study period. Continued use resulted in a further significant reduction in plaque scores irrespective of the gender of participants. PMID:27630494

  13. Plaque removal efficacy of Colgate 360 toothbrush: A clinical study

    Directory of Open Access Journals (Sweden)

    Nageshwar Iyer

    2016-01-01

    Full Text Available Aim: The aim of this clinical study was to confirm the plaque removal efficacy of the Colgate 360 Whole Mouth Clean Toothbrush. Study Design: This was a single-center, monadic, case-controlled study with the 7 days duration. Materials and Methods: A total of eighty participants (56 male and 24 female aged between 18 and 45 years with a minimum of 20 permanent teeth (excluding the third molars without any prosthetic crowns and an initial plaque score of minimum 1.5 as determined by Modified Quigley-Hein Plaque Index (1970 participated in the study. There were two dropouts during the study duration, one male and one female. The participants were instructed to brush for 1 min, after which plaque index was recorded again. They were then instructed to brush their teeth twice a day for 1 min with the assigned toothbrush (Colgate 360 Whole Mouth Clean Toothbrush and a commercially available fluoride toothpaste for the next 7 days. On the 7 th day, all the participants were recalled for follow-up and plaque examination. The plaque index scores (pre- and post-brushing were recorded, tabulated, and analyzed statistically. Results: The mean plaque indices reduced after brushing both on day 1 and day 7. There was also a reduction in mean plaque indices from day 1 to day 7. All these reductions were statistically significant (P < 0.001. The reduction in plaque scores was independent of the gender of the participants however female participants showed lower scores as compared to male participants (P < 0.001. Conclusion: The present study demonstrated a significant reduction in plaque scores with the use of Colgate 360 Whole Mouth Clean Soft Toothbrush throughout the study period. Continued use resulted in a further significant reduction in plaque scores irrespective of the gender of participants.

  14. Wetting properties of fungi mycelium alter soil infiltration and soil water repellency in a γ-sterilized wettable and repellent soil.

    Science.gov (United States)

    Chau, Henry Wai; Goh, Yit Kheng; Vujanovic, Vladimir; Si, Bing Cheng

    2012-12-01

    Soil water repellency (SWR) has a drastic impact on soil quality resulting in reduced infiltration, increased runoff, increased leaching, reduced plant growth, and increased soil erosion. One of the causes of SWR is hydrophobic fungal structures and exudates that change the soil-water relationship. The objective of this study was to determine whether SWR and infiltration could be manipulated through inoculation with fungi. The effect of fungi on SWR was investigated through inoculation of three fungal strains (hydrophilic -Fusarium proliferatum, chrono-amphiphilic -Trichoderma harzianum, and hydrophobic -Alternaria sp.) on a water repellent soil (WR-soil) and a wettable soil (W-soil). The change in SWR and infiltration was assessed by the water repellency index and cumulative infiltration respectively. F. proliferatum decreased the SWR on WR-soil and slightly increased SWR in W-soil, while Alternaria sp. increased SWR in both the W-soil and the WR-soil. Conversely T. harzianum increased the SWR in the W-soil and decreased the SWR in the WR-soil. All strains showed a decrease in infiltration in W-soil, while only the F. proliferatum and T. harzianum strain showed improvement in infiltration in the WR-soil. The ability of fungi to alter the SWR and enmesh soil particles results in changes to the infiltration dynamics in soil. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  15. 蚊虫驱避剂的驱避机理研究%Repelling mechanism of mosquitoes repellent

    Institute of Scientific and Technical Information of China (English)

    廖圣良; 姜志宽; 宋杰; 王宗德; 韩招久; 陈金珠

    2012-01-01

    A review about the research of repelling mechanism is presented.Two mainstream hypotheses possible repelling mechanisms have been proposed:repellent interferes with the mosquitoes olfactory system to block the recognition of the host odor,therefore,mosquitoes can' t detect the existance of the host ; or mosquitoes evade host after its olfactory neuron is activated by repellent.Some research relating repellent in the author(s) laboratory was introduced as well,especially the investigation on repelling mechanism from the perspective of association between repellent and attractant.%本文就蚊虫驱避机理的研究进行了综述,详细介绍了目前两类主流的驱避机理假说:驱避剂干扰嗅觉系统以阻断蚊虫对宿主气味的识别、驱避剂激活嗅觉神经元引起蚊虫的主动躲避行为.介绍了笔者所在实验室近几年对驱避剂进行的相关研究,以及从驱避剂与引诱剂缔合作用的角度对驱避机理的研究.

  16. STUDIES ON THE EFFICACY OF BRIDELIA FERRUGINEA BENTH ...

    African Journals Online (AJOL)

    Further research into it's efficacy in waste water treatment is desirable so that it may ... Two hundred grams of the powdered bark were dissolved in solvent .... By their nature, the wastes arising from food, beverages and soft drinks processing.

  17. Essential Oil Repellents- A short Review

    Directory of Open Access Journals (Sweden)

    R V GEETHA

    2014-06-01

    Full Text Available Mosquitoes are the most important of insects in terms of public health importance which transmit a number of diseases such as dengue, chikungunya, Japanese B encephalitis, filariasis and malaria, causing millions of deaths every year. Mosquito control and personal protection from mosquito bites are currently the most important measures to prevent these diseases. Essential oils from plants have been recognized as important natural resources of insecticides because some are selective, biodegrade to non-toxic products and have few effects on non-target organisms and environment. Essential oils are volatile mixtures of hydrocarbons with a diversity of functional groups, and their repellent activity has been linked to the presence of mono - terpenes and sesquiterpenes. In some cases, these chemicals can work synergistically, improving their effectiveness. The aim of this review is to highlight the significance of essential oil from Cymbopogon winterianus Jowitt, Azadirchata indica, Lavandula angustifolia, Mentha piperita for control of vector- borne disease

  18. Two-Region Model for Soil Water Repellency as a Function of Matric Potential and Water Content

    DEFF Research Database (Denmark)

    Karunarathna, Anurudda Kumara; Møldrup, Per; Kawamoto, Ken

    2010-01-01

    Soil water repellency (WR) occurs worldwide and affects hydrologic processes such as infiltration, preferential flow, and surface erosion. The degree of WR varies with soil organic C (SOC) and water contents. In this study, we measured WR (by ethanol molarity) as a function of moisture conditions...... for two soil profiles (17 layers, of which 13 exhibited WR), representing different vegetation and SOC between 0.6 and 14%. Generally, WR was found at SOC ≥2%. Based on measured data, a two-region water repellency (TRWR) model was developed. The model assumes two linear regions in a WR vs. pF (=log...... by the so-called Dexter index) is useful for predicting if soils are likely to exhibit WR. Expression of soil water repellency depends on soil water content; however, only a limited amount of predictive description is available to date. In this study, based on experimental data, a simple two-region model...

  19. Larvicidal and repellent properties of some essential oils against Culex tritaeniorhynchus Giles and Anopheles subpictus Grassi (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu

    2011-02-01

    To investigate the larvicidal and repellent properties of essential oils from various parts of four plant species Cymbopogan citrates, Cinnamomum zeylanicum, Rosmarinus officinalis and Zingiber officinale against Culex tritaeniorhynchus (Cx. tritaeniorhynchus) and Anopheles subpictus (An. subpictus). Essential oils were obtained by hydro-distillation method. The mosquitoes were reared in the vector control laboratory and twenty five late third instar larvae of Cx. tritaeniorhynchus and An. subpictus were exposed to based on the wide range and narrow range test, essential oil tested at various concentrations ranging from 25 to 250 ppm. The larval mortality was observed after 24 h under the laboratory conditions. The repellent efficacy was determined against two mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm(2) under laboratory conditions. Results showed all the four plant essential oil produced significant larval mortality against two mosquito species. However, the highest larvicidal activity was observed in the essential oil from Zingiber officinale against Cx. tritaeniorhynchus and An. subpictus with the LC(50) and LC(90) values as 98.83, 57.98 ppm and 186.55, 104.23 ppm, respectively. All the four essential oil shows significant repellency against Cx. tritaeniorhynchus than An. subpictus. Among four essential oil tested the highest repellency was observed in Zingiber officinale, a higher concentration of 5.0 mg/cm(2) provided 100% protection up to 150 and 180 min against Cx. tritaeniorhynchus and An. subpictus, respectively. In this work, it can be concluded that four essential oils which were distilled from Cymbopogan citrates, Cinnamomum zeylanicum, Rosmarinus officinalis and Zingiber officinale showed promising larvicidal and repellent agent against Cx. tritaeniorhynchus and An. subpictus. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  20. Efficacy of glutathione mesotherapy in burns: an experimental study.

    Science.gov (United States)

    Buz, A; Görgülü, T; Olgun, A; Kargi, E

    2016-12-01

    Thermal burns are the leading cause of trauma worldwide. Currently, no consensus on optimal treatment of deep partial-thickness (second-degree) burns has emerged, as reflected by the wide variability in available wound-care materials. The relative efficacies of products used for treatment of partial-thickness thermal burns remain unclear. Mesotherapy features intradermal administration of various agents, depending on burn location. In the present experimental study, we explored the efficacy of mesotherapy used to treat partial-thickness thermal burns in 50 male Wistar rats divided into five groups of equal number. No procedure was performed after infliction of thermal burns in control group (Group 1). Mesotherapy was applied with physiological saline in sham group (Group 2), glutathione, taurine, and L-carnitine were separately applied in Group 3, Group 4, and Group 5, respectively. Mesotherapeutic agents were injected intradermally into the reticular layer of the dermis using the point technique. The first course of mesotherapy was given within the first 2 h after infliction of thermal burns, and therapy was continued to day 10. On day 22, unhealed thermal burn areas were measured prior to sacrifice, and biopsies covering the total areas of burns were performed to allow of pathological evaluation. Group 3 (the glutathione group) showed the best extent of healing, followed by Group 4 (the taurine group) and Group 5 (the L-carnitine group). The healed thermal burn areas in these groups were significantly greater than those in the control and sham groups (P = 0.001). All of healing, acute and chronic inflammation, the amount of granulation tissue, the level of fibroblast maturation, the amount of collagen, the extent of re-epithelization and neovascularization, and ulcer depth were scored upon pathological examination of tissue cross-sections. The best outcomes were evident in the glutathione group, with statistical significance. Although wound healing in the L

  1. Studies on bactericidal efficacy of pumpkin (Cucurbita moschata Duchesne) peel

    Institute of Scientific and Technical Information of China (English)

    El Zawane Kamarudin; Qamar Uddin Ahmed; Zuvairea Nazren Mohd Sirajudin; Ahmad Jalal Khan Chowdhury

    2014-01-01

    Objective: To explore the in vitro antibacterial potential of the peel of Cucurbita moschata Duchesne (tropical pumpkin) (C. moschata) against human pathogenic bacteria. Methods:In the present study, dichloromethane (DCM), methanol (MEOH) and aqueous extracts of C. moschata peel were examined for in vitro antibacterial potency against eight bacterial strains i.e. Bacillus cereus, Burkholderia cepacia, Escherichia coli, Enterococcus faecalis, Staphyloccocus aureus, Pseudomonas aerugenosa, Vibrio alginolyticus, Vibrio parahaemolyticus using Kirby-Bauer disk diffusion susceptibility and broth micro-dilution methods. Results: DCM extract of pumpkin peel exhibited the maximum zone of inhibition against Staphyloccocus aureus (21 mm) whereas aqueous extract of pumpkin peel revealed the least zone of inhibition against Escherichia coli (8 mm). MEOH extract gave maximum zone of inhibition against Pseudomonas aerugenosa (19 mm). Broth micro-dilution method showed minimum inhibitory concentration for the DCM extract against Burkholderia cepacia at 6.25 mg/mL. The minimum bactericidal concentrations were also determined to know the nature of all extracts. DCM and MEOH extracts exhibited bactericidal nature to all bacterial strains except for the Vibrio alginolyticus. The minimum bactericidal concentrations values exhibited bactericidal nature ranging from 3.12 mg/mL to 100.00 mg/mL. The screening of antimicrobial properties of different extracts of C. moschata peel revealed that the DCM extract possessed good antimicrobial efficacy compared to MEOH and aqueous extracts. Conclusions: Peel of C. moschata possesses antibacterial compounds and could be potential source for a new class of antibiotics.

  2. Discussion on the pharmacology and function of the plants mosquito repelled%驱蚊植物药理与作用研究概述

    Institute of Scientific and Technical Information of China (English)

    黄清臻; 史慧勤; 杨振洲; 李彦; 韩华; 石华

    2012-01-01

    概述了驱蚊植物的种类、药理作用和驱避方式研究情况,介绍了几种常见的观赏性驱蚊植物的特点.%The article discusses the study development of the pharmacology and function of the plants mosquito repelled , summarizes the kinds of plants mosquito repelles and the characteristic of some ornamental plants mosquito repelled.

  3. Identifying the effective concentration for spatial repellency of the dengue vector Aedes aegypti.

    Science.gov (United States)

    Achee, Nicole; Masuoka, Penny; Smith, Philip; Martin, Nicholas; Chareonviryiphap, Theeraphap; Polsomboon, Suppaluck; Hendarto, Joko; Grieco, John

    2012-12-28

    Current efforts are underway to quantify the chemical concentration in a treated air space that elicits a spatial repellent (deterrent) response in a vector population. Such information will facilitate identifying the optimum active ingredient (AI) dosage and intervention coverage important for the development of spatial repellent tools--one of several novel strategies being evaluated for vector-borne disease control. This study reports initial findings from air sampling experiments conducted under field conditions to describe the relationship between air concentrations of repellent AIs and deterrent behavior in the dengue vector, Aedes aegypti. Air samples were taken inside and outdoors of experimental huts located in Pu Tuey Village, Kanchanaburi Province, Thailand in conjunction with mosquito behavioral evaluations. A mark-release-recapture study design using interception traps was used to measure deterrency of Ae. aegypti against 0.00625% metofluthrin coils and DDT-treated fabric (2g/m2) within separate experimental trials. Sentinel mosquito cohorts were positioned adjacent to air sampling locations to monitor knock down responses to AI within the treated air space. Air samples were analyzed using two techniques: the U.S. Environmental Protection Agency (USEPA) Compendium Method TO-10A and thermal desorption (TD). Both the USEPA TO-10A and TD air sampling methods were able to detect and quantify volatized AIs under field conditions. Air samples indicated concentrations of both repellent chemicals below thresholds required for toxic responses (mortality) in mosquitoes. These concentrations elicited up to a 58% and 70% reduction in Ae. aegypti entry (i.e., deterrency) into treated experimental huts using metofluthrin coils and DDT-treated fabric, respectively. Minimal knock down was observed in sentinel mosquito cohorts positioned adjacent to air sampling locations during both chemical evaluations. This study is the first to describe two air sampling

  4. Identifying the effective concentration for spatial repellency of the dengue vector Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Achee Nicole

    2012-12-01

    Full Text Available Abstract Background Current efforts are underway to quantify the chemical concentration in a treated air space that elicits a spatial repellent (deterrent response in a vector population. Such information will facilitate identifying the optimum active ingredient (AI dosage and intervention coverage important for the development of spatial repellent tools – one of several novel strategies being evaluated for vector-borne disease control. This study reports initial findings from air sampling experiments conducted under field conditions to describe the relationship between air concentrations of repellent AIs and deterrent behavior in the dengue vector, Aedes aegypti. Methods Air samples were taken inside and outdoors of experimental huts located in Pu Tuey Village, Kanchanaburi Province, Thailand in conjunction with mosquito behavioral evaluations. A mark-release-recapture study design using interception traps was used to measure deterrency of Ae. aegypti against 0.00625% metofluthrin coils and DDT-treated fabric (2g/m2 within separate experimental trials. Sentinel mosquito cohorts were positioned adjacent to air sampling locations to monitor knock down responses to AI within the treated air space. Air samples were analyzed using two techniques: the U.S. Environmental Protection Agency (USEPA Compendium Method TO-10A and thermal desorption (TD. Results Both the USEPA TO-10A and TD air sampling methods were able to detect and quantify volatized AIs under field conditions. Air samples indicated concentrations of both repellent chemicals below thresholds required for toxic responses (mortality in mosquitoes. These concentrations elicited up to a 58% and 70% reduction in Ae. aegypti entry (i.e., deterrency into treated experimental huts using metofluthrin coils and DDT-treated fabric, respectively. Minimal knock down was observed in sentinel mosquito cohorts positioned adjacent to air sampling locations during both chemical evaluations. Conclusions

  5. Using Repellent Products to Protect against Mosquito-Borne Illnesses

    Science.gov (United States)

    ... Us Share Using Repellent Products to Protect against Mosquito-Borne Illnesses More Information CDC-Avoid Mosquito Bites ... safety precautions . Top of Page Finding EPA-Registered Mosquito Adulticides and Larvicides The National Pesticide Information Center's ...

  6. Prevention of vector transmitted diseases with clove oil insect repellent.

    Science.gov (United States)

    Shapiro, Rochel

    2012-08-01

    Vector repellent is one element in the prevention of vector-borne diseases. Families that neglect protecting their children against vectors risk their children contracting illnesses such as West Nile virus, eastern equine encephalitis, Lyme disease, malaria, dengue hemorrhagic fever, yellow fever, babesiosis, Crimean-Congo hemorrhagic fever, Rocky Mountain spotted fever, Southern tick-associated rash illness, ehrlichiosis, tick-borne relapsing fever, tularemia, and other insect and arthropod related diseases (CDC, 2011). Identification of families at risk includes screening of the underlying basis for reluctance to apply insect repellent. Nurses and physicians can participate in a positive role by assisting families to determine the proper prophylaxis by recommending insect repellent choices that are economical, safe, and easy to use. A holistic alternative might include the suggestion of clove oil in cases where families might have trepidations regarding the use of DEET on children. This article will explore the safety and effectiveness of clove oil and its use as an insect repellent.

  7. Comparative repellency of 38 essential oils against mosquito bites.

    Science.gov (United States)

    Trongtokit, Yuwadee; Rongsriyam, Yupha; Komalamisra, Narumon; Apiwathnasorn, Chamnarn

    2005-04-01

    The mosquito repellent activity of 38 essential oils from plants at three concentrations was screened against the mosquito Aedes aegypti under laboratory conditions using human subjects. On a volunteer's forearm, 0.1 mL of oil was applied per 30 cm2 of exposed skin. When the tested oils were applied at a 10% or 50% concentration, none of them prevented mosquito bites for as long as 2 h, but the undiluted oils of Cymbopogon nardus (citronella), Pogostemon cablin (patchuli), Syzygium aromaticum (clove) and Zanthoxylum limonella (Thai name: makaen) were the most effective and provided 2 h of complete repellency. From these initial results, three concentrations (10%, 50% and undiluted) of citronella, patchouli, clove and makaen were selected for repellency tests against Culex quinquefasciatus and Anopheles dirus. As expected, the undiluted oil showed the highest protection in each case. Clove oil gave the longest duration of 100% repellency (2-4 h) against all three species of mosquito.

  8. Surface Treatment of Building Materials with Water Repellent Agents

    OpenAIRE

    Wittman, F.H.; Siemes, T.A.J.M.; Verhoef, L.G.W.

    1995-01-01

    Water repellent agents have been applied to proteet building materials and structural elements for thousands ofyears. Initially, natural products, such as oils and fats were used exclusively. More recently, synthetic organic compounds are being developed for special applications.

  9. A Water-repellent Silanization Coating Technique for MEMS

    Science.gov (United States)

    Shimaoka, Keiichi; Hosokawa, Hideki; Funabashi, Hirohumi; Mitsushima, Yasuichi

    A gas-phase water-repellent silanization coating technique, which prevents the microscopic structures used for micro-sensors and micro-electro-mechanical systems (MEMS) from sticking to the silicon substrates and other microscopic structures during operation, have been developed. Use of a water-repellent coating is one method that prevents sticking by reducing the surface energy of the structure. The water-repellency characteristics of three types of organosilicon compounds were evaluated. It was found that a water-repellent silanization coating layer using (tridecafluoro - 1, 1, 2, 2 -tetrahydrooctyl) trichlorosilane (C8H4Cl3F13Si) had most excellent durability. It was confirmed that the water contact angle of C8H4Cl3F13Si coating layer is exceeding 90 degrees at surface of standard semiconductor materials except nickel. In addition, the C8H4Cl3F13Si coating layer can be patterned by ultraviolet irradiation.

  10. Evaluation of the Repellent and Insecticidal Activities of the Leaf ...

    African Journals Online (AJOL)

    ADOWIE PERE

    high repellent and insecticidal activities demonstrated by the root powder ... generally low as a result of serious insect pest attacks ..... to have clear insecticidal properties (DeGeyter, 2012) ... nematicidal ingredients from neem leaves, siam.

  11. A Primary Screening and Applying of Plant Volatiles as Repellents to Control Whitefly Bemisia tabaci (Gennadius) on Tomato

    Science.gov (United States)

    Du, Wenxiao; Han, Xiaoqing; Wang, Yubo; Qin, Yuchuan

    2016-02-01

    With the goal of finding a new way to reduce population densities of Bemisia tabaci biotype Q in greenhouses, seven repellent volatile chemicals and their combinations were screened. The mixture of DLCO (D-limonene, citral and olive oil (63:7:30)) had a better cost performance(SC50 = 22.59 mg/ml)to repel whiteflies from settling than the other mixtures or single chemicals. In the greenhouse, in both the choice test and the no-choice tests, the number of adult whiteflies that settled on 1% DLCO-treated tomato plants was significantly lower than those settling on the control plants for the different exposure periods (P  0.05) between the number of eggs on treated and control plants in the no-choice test. Compared with the controls, 1% DLCO did not cause significantly statistic mortality rates (P > 0.05) out of different living stages of B. tabaci. The tests for evaluating the repellent efficacy, showed that a slow-releasing bottle containing the mixture had a period of efficacy of 29 days, and the application of this mixture plus a yellow board used as a push-pull strategy in the greenhouse was also effective.

  12. Wash resistance and repellent properties of Africa University mosquito blankets against mosquitoes

    OpenAIRE

    N. Lukwa; A. Makuwaza; T. Chiwade; Mutambu, S L; M. Zimba; P. Munosiyei

    2013-01-01

    The effect of permethrin-treated Africa University (AU) mosquito blankets on susceptible female Anopheles gambiae sensu lato mosquitoes was studied under laboratory conditions at Africa University Campus in Mutare, Zimbabwe. Wash resistance (ability to retain an effective dose that kills ≥80% of mosquitoes after a number of washes) and repellence (ability to prevent ≥80% of mosquito bites) properties were studied. The AU blankets were wash resistant when 100% mortality was recorded up t...

  13. The influence of water repellent products on the chromatic modifications of the ceramic brick

    Directory of Open Access Journals (Sweden)

    Coronado Martin, J. A.

    2011-12-01

    Full Text Available Chromatic variation, colour and luminosity, undergone by the ceramic support protected by the incorporation of a treatment with water repellent products, is analysed. A new methodology is suggested, based on RGB model where quantifiable values from each ceramic sample are obtained through digital measurement of the colour (image histograms, taking as a base the same type of ceramics with no water repellents. Chromatic variation is determined by the type of water repellent and the base material, obtaining the following results: - All the water repellent studied cause variations in the shade and luminosity of the piece. - English red brick (R is the one presenting less variation of luminosity and shade since it’s been treated with water repellents. - The water repellent of siliconates component is the one which causes less chromatic variation in two of the three bricks studied, the dark brown (T and the English red (R one.

    Se analiza la variación cromática, color y luminosidad, que sufre el soporte cerámico protegido por la incorporación de un tratamiento con productos hidrofugantes. Se propone una metodología nueva, basada en el modelo RGB donde se obtienen valores cuantificables de cada muestra cerámica mediante medición digital del color (histogramas de imagen, tomándose como base el mismo tipo de cerámica sin hidrofugar. La variación cromática está determinada por el tipo de hidrofugante y por el material de base, obteniéndose los siguientes resultados: - Todos los hidrofugantes estudiados producen variación en la tonalidad y luminosidad de la pieza. - El ladrillo rojo ingles (R es el que presenta menor variación de luminosidad y tonalidad al ser tratado con hidrofugantes. - El hidrofugante de componente siliconatos es el que menor variación cromática produce en dos de los tres ladrillos estudiados, tostado (T y rojo inglés (R.

  14. A systematic review of mosquito coils and passive emanators: defining recommendations for spatial repellency testing methodologies

    Directory of Open Access Journals (Sweden)

    Ogoma Sheila B

    2012-12-01

    Full Text Available Abstract Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS, long lasting insecticide treated nets (LLINs and insecticide treated materials (ITMs. PubMed, (National Centre for Biotechnology Information (NCBI, U.S. National Library of Medicine, NIH, MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words “Mosquito coils” “Mosquito emanators” and “Spatial repellents”. It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose–response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP, which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control.

  15. Determining airborne concentrations of spatial repellent chemicals in mosquito behavior assay systems.

    Directory of Open Access Journals (Sweden)

    Nicholas J Martin

    Full Text Available BACKGROUND: Mosquito behavior assays have been used to evaluate the efficacy of vector control interventions to include spatial repellents (SR. Current analytical methods are not optimized to determine short duration concentrations of SR active ingredients (AI in air spaces during entomological evaluations. The aim of this study was to expand on our previous research to further validate a novel air sampling method to detect and quantitate airborne concentrations of a SR under laboratory and field conditions. METHODOLOGY/PRINCIPAL FINDINGS: A thermal desorption (TD gas chromatography-mass spectrometry (GC-MS method was used to determine the amount of dichlorodiphenyltrichloroethane (DDT in samples of air. During laboratory experiments, 1 L volumes of air were collected over 10 min intervals from a three-chamber mosquito behavior assay system. Significantly higher levels of airborne DDT were measured in the chamber containing textiles treated with DDT compared to chambers free of AI. In the field, 57 samples of air were collected from experimental huts with and without DDT for onsite analysis. Airborne DDT was detected in samples collected from treated huts. The mean DDT air concentrations in these two huts over a period of four days with variable ambient temperature were 0.74 µg/m(3 (n = 17; SD = 0.45 and 1.42 µg/m(3 (n = 30; SD = 0.96. CONCLUSIONS/SIGNIFICANCE: The results from laboratory experiments confirmed that significantly different DDT exposure conditions existed in the three-chamber system establishing a chemical gradient to evaluate mosquito deterrency. The TD GC-MS method addresses a need to measure short-term (<1 h SR concentrations in small volume (<100 L samples of air and should be considered for standard evaluation of airborne AI levels in mosquito behavior assay systems. Future studies include the use of TD GC-MS to measure other semi-volatile vector control compounds.

  16. A repellent for protecting corn seed from blackbirds and crows

    Science.gov (United States)

    Stickley, A.R.; Guarineo, J.L.

    1972-01-01

    Methiocarb [4-(methylthio)-3,-5-xylyl N-methylcarbamate] was tested as a seed treatment for repelling blackbirds and crows (Corvus sp.) from sprouting corn in South Carolina. The test was conducted on eight fields within a 0.25-square-mile area. Marked repellency occurred; sprout damage averaged 44 percent in the control fields and 0.3 percent in the fields treated with methiocarb.

  17. Strange Quasi-Repeller in a Kicked Rotor

    Institute of Scientific and Technical Information of China (English)

    姜玉梅; 何大韧

    2003-01-01

    A new kind of crisis was observed in a system where a transition from conservative toquasi-dissipative can be observed. The crisis signifies a sudden and intrinsic change of a stochasticweb, which is formed by the end-results of the images of the discontinuous borderlines of the systemfunction. In the crisis, a strange quasi-repeller can be defined. When changing the controllingparameter, the variation of the fractile dimension of the quasi-repeller obeys a logarithmic rule.

  18. Measurements of water repellency and infiltration of the soil

    OpenAIRE

    Žnidaršič, Petra

    2013-01-01

    Soil water repellency is a reduction in the rate of wetting caused by the presence of hydrophobic coatings on soil particles. The occurrence of the absorption of water from the surface of the ground in its interior is called infiltration. Water resistance and infiltration are dependent on a number of influences. All measurements were done on three different soil types at each at the ground level and in the trench. Water repellency measurements were performed by two methods, namely with wat...

  19. Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

    Science.gov (United States)

    2010-08-01

    products include the active ingredients N,N- diethyl -3-methylbenzamide (DEET), Insect Repellent 3535 (IR3535), and more recently Picaridin and 2...than the odorant. DEET and indole share an aromatic ring and a nitrogen-linked function. 2-U and octenol share a similar carbon backbone, and 2-U has a...effects of all four repellents were reversible upon fresh exposure to the odorant alone, suggesting that the interaction between the inhibitors and the ORs

  20. The Study of Teacher Efficacy in Hong Kong Sub-Degree Sector

    Directory of Open Access Journals (Sweden)

    Wai-Hung Lam

    2012-01-01

    Full Text Available Introduction. Sub-degree sector is rising in Hong Kong. The number of enrolled students was over 50000 in 2011. Students’ characteristics and teachers’ roles in the sub-degree sector are different from other sectors. It was important to investigate the factors related with teacher efficacy of sub-degree teachers. Method. Sixty sub-degree teachers were surveyed, and 58 of them were valid (33 males and 25 females. The questionnaire contained three teacher efficacy scales: Teacher Efficacy Scale (TES (short form, Bandura’s Instrument Teacher Self-Efficacy Scale (TSES, and Teachers’ Sense of Efficacy Scale (TSoES and an instrument of self-rating’s levels of concerns. Results. The teacher efficacy scales were found to be reliable in the sub-degree sector. The levels of education and educational trainings were not found to be related with any teacher efficacy scales. Level of concerns of teacher efficacy was found to be significant related with TSES’ efficacy to influence parental involvement and ToSES’s instruction strategies. Conclusion. This study found that educational trainings and levels of educations were not related with teacher efficacy and could persuade institutes not to view educational backgrounds as the most influencing factor in employment selections and design better staff developments instead of only sponsoring teachers to pursue further studies.

  1. Alflutop clinical efficacy in vertebral osteochondrosis (12-mohth study

    Directory of Open Access Journals (Sweden)

    V N Hodyrev

    2005-01-01

    Full Text Available Objective. To study clinical efficacy of aiflutop (A in lumbar osteochondrosis (LO with chronic back pain syndrome. Material and Methods. 32 pts with LO were included. 14 from them (group 1 during a year received 2 courses of A intramuscular injections (I ml/day, 30 ml total and nonsteroidal anti-inflammatory drugs (NSAIDs if necessary. 18 pts (group 2 received NSAIDs only. Clinical examination of pts was performed at the stert of the study, before and after each A course and in 3 months after the last course. Results. Pain in the spine at rest and forward bending significantly decreased in group 1 pts (p<0,05 after each A course. Full pain disappearance after the first A course was achieved in 7,1% and after the second course - in 35,7% of group I pts and was not shown in control group. Significant stepped decrease of Thomayer's test value (p<0,00l was also shown in group 1: 3,6 times decrease in comparison with baseline was achieved in 3 months after completion of treatment with A. During treatment period these pts showed 2-2,5 times increase of static and dynamic spine load (according to Vxdel chronic inability index. 42,9% of group I pts stopped NSAIDs after A treatment completion. Only 5,6% of control group pts stopped NSAIDs during follow up. A tolerability was good. It can be combined with any other medications the pts received due to comorbid diseases.

  2. Toxicity of a plant based mosquito repellent/killer.

    Science.gov (United States)

    Singh, Bhoopendra; Singh, Prakash Raj; Mohanty, Manoj Kumar

    2012-12-01

    The mission to make humans less attractive to mosquitoes has fuelled decades of scientific research on mosquito behaviour and control. The search for the perfect topical insect repellent/killer continues. This analysis was conducted to review and explore the scientific information on toxicity produced by the ingredients/contents of a herbal product. In this process of systemic review the following methodology was applied. By doing a MEDLINE search with key words of selected plants, plant based insect repellents/killers pertinent articles published in journals and authentic books were reviewed. The World Wide Web and the Extension Toxicity Network database (IPCS-ITOX) were also searched for toxicology data and other pertinent information. Repellents do not all share a single mode of action and surprisingly little is known about how repellents act on their target insects. Moreover, different mosquito species may react differently to the same repellent. After analysis of available data and information on the ingredient, of the product in relation to medicinal uses, acute and chronic toxicity of the selected medicinal plants, it can be concluded that the ingredients included in the herbal product can be used as active agents against mosquitoes. If the product which contains the powder of the above said plants is applied with care and safety, it is suitable fo use as a mosquito repellent/killer.

  3. An Empirical Study to Determine The Relationship between Occupational Self-Efficacy and Organizational Silence

    Directory of Open Access Journals (Sweden)

    Cem KAHYA

    2015-06-01

    Full Text Available The concept of occupational self-efficacy means the efficacy perceptions of employees in their occupational fields, and the concept of organizational silence means the employees avoid to voice their ideas and suggestions about organizational issues. The main aim of this study is to examine the relationship between the concepts of occupational self-efficacy and organizational silence by revealing employees’ perceptions of occupational self-efficacy and organizational silence level. With this aim, the survey study was conducted on total 114 academicians who work in University of Bayburt. As a result of research, while the significant relationship was found between employees’ perceptions of occupational self-efficacy and organizational silence level, there was reached a result that this relationship incurred the negatively relationship between perceptions of occupational self-efficacy and negative silence.

  4. Postfire soil water repellency in piñon-juniper woodlands: Extent, severity, and thickness relative to ecological site characteristics and climate.

    Science.gov (United States)

    Zvirzdin, Daniel L; Roundy, Bruce A; Barney, Nicholas S; Petersen, Steven L; Anderson, Val J; Madsen, Matthew D

    2017-07-01

    Wildfires can create or intensify water repellency in soil, limiting the soil's capacity to wet and retain water. The objective of this research was to quantify soil water repellency characteristics within burned piñon-juniper woodlands and relate this information to ecological site characteristics. We sampled soil water repellency across forty-one 1,000 m(2) study plots within three major wildfires that burned in piñon-juniper woodlands. Water repellency was found to be extensive-present at 37% of the total points sampled-and strongly related to piñon-juniper canopy cover. Models developed for predicting SWR extent and severity had R(2)adj values of 0.67 and 0.61, respectively; both models included piñon-juniper canopy cover and relative humidity the month before the fire as coefficient terms. These results are important as they suggest that postfire water repellency will increase in the coming years as infilling processes enhance piñon-juniper canopy cover. Furthermore, reductions in relative humidity brought about by a changing climate have the potential to link additively with infilling processes to increase the frequency and intensity of wildfires and produce stronger water repellency over a greater spatial extent. In working through these challenges, land managers can apply the predictive models developed in this study to prioritize fuel control and postfire restoration treatments.

  5. Field evaluation of G10, a celery (Apium graveolens)-based topical repellent, against mosquitoes (Diptera: Culicidae) in Chiang Mai province, northern Thailand.

    Science.gov (United States)

    Tuetun, B; Choochote, W; Pongpaibul, Y; Junkum, A; Kanjanapothi, D; Chaithong, U; Jitpakdi, A; Riyong, D; Wannasan, A; Pitasawat, B

    2009-02-01

    The potential of G10, a celery (Apium graveolens)-based topical product, as a repellent against natural mosquito populations was evaluated in comparison to commercial (Insect Block 28) and standard (25% DEET) repellents in Chiang Mai province, northern Thailand. These repellent products afforded encouragingly excellent personal protection against a broad range of mosquito species belonging to various genera, including Aedes, Anopheles, Armigeres, Culex, and Mansonia. No mosquito bite was observed on the volunteers treated with G10 and Insect Block 28 throughout the field study, whereas two species, i.e., six A. barbirostris and two A. subalbatus, came to bite or land on 25% DEET-treated volunteers. Thus, it can be concluded that while G10 and Insect Block 28 exhibited similarly powerful repellent activities with complete (100%) protection, 25% DEET was effective in minimizing bites with 99.68% protection. G10 formula was also studied for physical properties and biological stability after being kept under two conditions; a heating and cooling cycle, and varying temperature and time storage. Most samples of stored G10 not only demonstrated a similarity in appearance and physical properties, but also provided comparable repellency to that of the fresh preparation. These findings encourage commercial development of G10 formula as an alternative to conventional synthetic repellents.

  6. THE STUDY THE EFFICACY AND SAFETY OF ANTIMICROBIAL AGENTS

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    V. V. Bagaeva

    2015-01-01

    Full Text Available Abstract:Effective treatment of patients with infectious and inflammatory diseases of the skin and mucous membranes often involves the use of antimicrobial agents.The purpose of the study was an in vitro estimation of cytotoxicity and the efficiency of national resources for local use: gel with bacteriophages («Otofag», «Fagogin», «Fagoderm», «Fagodent» and antiseptic — «Сhlorhexidine» and «Miramistin».Materials and Methods. To study the effectiveness of antimicrobial agents they used to provide crop strains of Staphylococcus aureus and Streptococcus pyogenes as one of the most common representatives of pathogens. The study of cell viability and cytotoxicity antimicrobials performed on cell lines KB — epidermoid carcinoma of the oral cavity of a human. For this purpose we use mikrotetrazoly test, which is widely used in the assessment of the effects on the cells of toxins, pharmaceuticals, adverse environmental factors, allowing to evaluate the toxicity of investigational drugs in vitro.The results showed that the efficacy against pathogens Staphylococcus aureus and Streptococcus pyogenes, has even a 10‑fold dilution of «Сhlorhexidine» 0.05% and gels with bacteriophages. Antiseptic «Miramistin» is effective only on the initial concentration. The study of cytotoxicity showed that the processing of epidermoid carcinoma cells with «Chlorhexidine» and «Мiramistin» invokes the irreversible reactions, while the composition processing of gels based on bacteriophages not further affect cell viability.Conclusions The results of the experiment confirmed the significant toxicity of tools such as «Сhlorhexidine» and «Miramistin» in proposed concentrations in the pharmacy network. Despite the high efficiency of these vehicles with regard to the studied pathogens, their long-term use in treatment of inflammatory diseases of the skin and mucous membranes can cause a slowing of repair processes. Gel means with bacteriophages

  7. Bronchodilator efficacy of extrafine glycopyrronium bromide: the Glyco 2 study

    Directory of Open Access Journals (Sweden)

    Singh D

    2017-07-01

    Full Text Available Dave Singh,1 Mario Scuri,2 Sara Collarini,2 Stefano Vezzoli,2 Fabrizia Mariotti,2 Annamaria Muraro,2 Daniela Acerbi2 1Medicines Evaluation, University Of Manchester, University Hospital of South Manchester, Manchester, UK; 2Global Clinical Development, Chiesi Farmaceutici SpA, Parma, Italy Abstract: An extrafine formulation of the long-acting muscarinic antagonist glycopyrronium bromide (GB is in development for chronic obstructive pulmonary disease (COPD, in combination with beclometasone dipropionate and formoterol fumarate – a “fixed triple”. This two-part study was randomized, double blind, placebo controlled in patients with moderate-to-severe COPD: Part 1: single-dose escalation, GB 12.5, 25, 50, 100 or 200 µg versus placebo; Part 2: repeat-dose (7-day, four-period crossover, GB 12.5, 25 or 50 µg twice daily (BID versus placebo, with an open-label extension in which all patients received tiotropium 18 µg once daily. On the morning of Day 8 in all five periods, patients also received formoterol 12 µg. In study Part 1, 27 patients were recruited. All GB doses significantly increased from baseline forced expiratory volume in 1 second (FEV1 area under the curve (AUC0–12h and peak FEV1, with a trend toward greater efficacy with higher GB dose. All adverse events were mild–moderate in severity, with a lower incidence with GB than placebo and no evidence of a dose–response relationship. In study Part 2, of 38 patients recruited, 34 completed the study. Adjusted mean differences from placebo in 12 h trough FEV1 on Day 7 (primary were 115, 142 and 136 mL for GB 12.5, 25 and 50 µg BID, respectively (all P<0.001. GB 25 and 50 µg BID were superior (P<0.05 to GB 12.5 µg BID for pre-dose morning FEV1 on Day 8. For this endpoint, GB 25 and 50 µg BID were also superior to tiotropium. Compared with Day 7, addition of formoterol significantly increased Day 8 FEV1 peak and AUC0–12h with all GB doses and placebo (all P<0.001. All

  8. STUDY ON THE WATER REPELLENT SILICONE-POLYURETHANE BLOCK COPOLYMERS%拒水型有机硅改性聚氨酯嵌段共聚物的合成与表征

    Institute of Scientific and Technical Information of China (English)

    张怀文; 杜淼; 王楠; 郑强

    2013-01-01

    以氨丙基硅氧烷偶联剂和端羟基聚二甲基硅氧烷(PDMS)为原料,合成了端氨丙基聚二甲基硅氧烷低聚物(SN2),并将其作为扩链剂,制备了有机硅-聚氨酯(Si-PU)嵌段共聚物.考察了聚氨酯预聚体的加料比(rNCO/OH)、SN2与聚氨酯预聚体的加料比(rNH2/NCO)对Si-PU嵌段共聚物溶液流变行为及其膜性能的影响.研究发现,该Si-PU共聚物的异丙醇溶液呈现较低的表观黏度及牛顿特性;成膜时,有机硅链段向表面迁移;膜表面对水的接触角达110°以上,且随着有机硅链段含量的增高而增大;共聚物膜的24 h吸水率较低(<1.5 wt%);但当有机硅链段含量过高时,吸水率反而增高.%Amino-terminated polydimethylsiloane ( SN2 ) was synthesized by using hydroxyl-terminated polydimethylsiloxane ( PDMS ) and aminopropyl siloxane coupling agent ( DB-912). And the silicone-polyurethane (Si-PU) block copolymer was synthesized by using SN2 as a chain extender and polyurethane prepolymer. The effects of the SN2 and prepolymer of polyurethane feed ratio on the rheological behavior of the copolymer solution in isopropanol (IPA) and the properties of its film were studied in detail. It was found that the Si-PU block copolymer IPA solution with a concentration of 25 wt% exhibited low apparent viscosity and the characteristics of Newtonian fluid within the measuring shear rate scope. During film casting,the SN2 blocks may migrate toward the surface,which led to a surface contact angle to water over 110°. With the increasing of SN2 block content,the surface contact angles of films to water increased slightly. When the films were soaked in the water for 24 h, the water absorptions were very low, and the water-repellence was pretty good. The copolymer film showed water absorption lower than 1. 5 wt% . With the increasing of SN2 block content, the water absorptions were very low and did not change a lot. However,if the content of SN2 block was too high

  9. Relationships between soil water repellency and microbial community composition under different plant species in a Mediterranean semiarid forest

    Science.gov (United States)

    Lozano, Elena; García-Orenes, Fuensanta; Bárcenas-Moreno, Gema; Jiménez-Pinilla, Patricia; Mataix-Solera, Jorge; Arcenegui, Victoria; Morugán-Coronado, Alicia; Mataix-Beneyto, Jorge

    2014-05-01

    It is generally well accepted that soil water repellency (SWR) can greatly influence the hydrology and the ecology of the forest soils (Doerr et al., 2000). However, little is known whether SWR may influence the soil microbial community. Its appearance is mainly influence by many soil physic- chemical parameters like: SOM content and its quality, pH, moisture, texture etc. However, it might also be influence by the presence or activity of microorganisms. Early studies suggest that SWR might be caused by substances produced by the activity of certain fungi species (Savage et al., 1969). Soil WR is normally characterized by a high spatial variability in persistence, with wettable and water repellent patches (Lozano et al., 2013). Changes at the microsite scale (such as the presence of soil water repellent patches) might be reflected in the microbial community structure). In the current study we have analysed how SWR influence the microbial community in soil samples with a range of water repellency persistence under different plant species (P. halepensis, Q. rotundifolia, C. albidus and R officinalis) in a Mediterranean forest. The microbial community was determined through phospholipids fatty acids (PLFA). The relationships between microbiological community structure and other different soil properties like pH, Glomalin Related Soil Protein and Soil Organic Matter content were also studied. Different statistical analyses were used: Principal Component Analysis (PCA), ANOVA, Redundancy Analysis (RA) and Pearson correlations. The highest concentrations of PLFA were found in water repellent samples. PCA showed that microorganism composition was more dependent of the severity of SWR than the type of plant species. In the RA, SWR was the only significant factor (pMataix-Solera, J., Arcenegui, V., Bárcenas, G.M., González-Pérez, J.A., García-Orenes, F., Torres, M.P., Mataix-Beneyto, J., 2013. Biological and chemical factors controlling the patchy distribution of soil

  10. Studies on bactericidal efficacy of pumpkin (Cucurbita moschata Duchesne peel

    Directory of Open Access Journals (Sweden)

    El Zawane Kamarudin

    2014-02-01

    Full Text Available Objective: T o explore the in vitro antibacterial potential of the peel of Cucurbita moschata D uchesne ( tropical pumpkin ( C. moschata against human pathogenic bacteria. Methods: I n the present study, dichloromethane ( DCM , methanol ( MEOH and aqueous extracts of C. moschata peel were examined for in vitro antibacterial potency against eight bacterial strains i.e. Bacillus cereus, Burkholderia cepacia, Escherichia coli, Enterococcus faecalis, Staphyloccocus aureus, Pseudomonas aerugenosa, Vibrio alginolyticus, Vibrio parahaemolyticus using K irby- B auer disk diffusion susceptibility and broth micro-dilution methods. Results: DCM extract of pumpkin peel exhibited the maximum zone of inhibition against Staphyloccocus aureus ( 21 mm whereas aqueous extract of pumpkin peel revealed the least zone of inhibition against Escherichia coli ( 8 mm . MEOH extract gave maximum zone of inhibition against Pseudomonas aerugenosa ( 19 mm . B roth micro-dilution method showed minimum inhibitory concentration for the DCM extract against Burkholderia cepacia at 6 . 25 mg/m L . T he minimum bactericidal concentrations were also determined to know the nature of all extracts. DCM and MEOH extracts exhibited bactericidal nature to all bacterial strains except for the Vibrio alginolyticus. T he minimum bactericidal concentrations values exhibited bactericidal nature ranging from 3 . 12 mg/m L to 100 . 00 mg/m L . T he screening of antimicrobial properties of different extracts of C. moschata peel revealed that the DCM extract possessed good antimicrobial efficacy compared to MEOH and aqueous extracts. Conclusions: P eel of C. moschata possesses antibacterial compounds and could be potential source for a new class of antibiotics.

  11. Field evaluation of spatial repellency of metofluthrin-impregnated plastic strips against Anopheles gambiae complex in Bagamoyo, coastal Tanzania.

    Science.gov (United States)

    Kawada, Hitoshi; Temu, Emmanuel A; Minjas, Japhet N; Matsumoto, Osamu; Iwasaki, Tomonori; Takagi, Masahiro

    2008-09-01

    Metofluthrin is a newly synthesized pyrethroid possessing high knockdown and lethal activity against mosquitoes. Studies of metofluthrin-impregnated plastic strips have been performed with dengue vectors. This study reports the efficacy of the new prototypes of metofluthrin-impregnated plastic strips against malaria vectors, Anopheles gambiae complex, in the Kongo villages of Bagamoyo district in coastal Tanzania. The study, using 20 houses, half intervention, half control, was conducted for a 124-day period. Pyrethrum spray sheets and Centers for Disease Control and Prevention light traps were used to sample mosquito population indices. The mosquito density indices of the intervention houses were observed to be significantly lower than those of the control houses when pyrethrum spray sheet collection was used (F = 4.61, 1 df, P = 0.038; 98.7% reduction of total mosquito collection compared with that for the controls). These low indices were observed despite the large openings found in Bagamoyo houses, which were predicted to have a considerable negative effect on the spatial repellency of metofluthrin. Based on the present results, the pyrethrum spray sheet collection was the better of the 2 collection methods.

  12. Excito-Repellency of Citrus hystrix DC Leaf and Peel Essential Oils Against Aedes aegypti and Anopheles minimus (Diptera: Culicidae), Vectors of Human Pathogens.

    Science.gov (United States)

    Nararak, Jirod; Sathantriphop, Sunaiyana; Kongmee, Monthathip; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2017-01-01

    The essential oils of kaffir lime (Citrus hystrix DC.) at four different concentrations (0.5, 1.0, 2.5, and 5.0% v/v) were studied for their repellency, excitation, and knockdown properties against laboratory strains of Aedes aegypti (L.) and Anopheles minimus Theobald using an excito-repellency test system. Both contact and noncontact escape responses to leaf- and peel-derived kaffir lime oils were observed. Comparing unadjusted escape responses for An. minimus, leaf oil had strong combined irritant and repellent activity responses at 1-5% concentrations (90.0-96.4% escape) and the strongest spatial repellent activity at 1% and 2% (85.9% and 87.2% escape, respectively). The peel oil exhibited good excitation with repellency at concentrations of 2.5% (89.8% escape) and 5% (96.28% escape), while concentrations 1-5% showed more moderate repellent activity against An. minimus. For Ae. aegypti, 2.5% leaf oil produced the greatest response for both contact (56.1% escape) and noncontact (63.3% escape) trials, while 2.5% produced the strongest response among all concentrations of peel oil, with 46.5% escape. However, after adjusting the contact trial escape (a measure of combined excitation and repellency), the estimated escape due to contact alone was a much weaker response than spatial repellency for both species. Knockdown responses above 50% were only observed in Ae. aegypti exposed to 5% leaf oil. Kaffir lime oils were more active against An. minimus than Ae. aegypti mosquitoes. There were statistically significant differences between leaf (more active) and peel oils at each concentration against An. minimus in contact and noncontact trials, except at the highest (5%) concentration. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

    Science.gov (United States)

    Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

    2016-04-01

    Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

  14. 21 CFR 201.200 - Disclosure of drug efficacy study evaluations in labeling and advertising.

    Science.gov (United States)

    2010-04-01

    ... labeling and advertising. 201.200 Section 201.200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Efficacy Study § 201.200 Disclosure of drug efficacy study evaluations in labeling and advertising. (a)(1...), promotional labeling, and advertisements shall include, as part of the information for practitioners...

  15. A Study on the Correlation between Self Efficacy and Foreign Language Learning Anxiety

    Science.gov (United States)

    Cubukcu, Feryal

    2008-01-01

    Anxiety in language learning is one of the less researched areas; that is why this study explores whether the anxiety level of foreign language learners is related to their self efficacy levels. For this purpose, 100 participants joined the study and the Foreign Language Learning Anxiety Scale and The Self Efficacy Scale were administered to them.…

  16. Self-Efficacy and Job Satisfaction of Early Career Elementary School Teachers: A Mixed Methods Study

    Science.gov (United States)

    Kirby, Deanne M.

    2011-01-01

    The purpose of this embedded mixed methods study was to determine the types of support and amounts of support most conducive to the development of early career teacher self-efficacy and job satisfaction. The study further examined the effect of job satisfaction and self-efficacy on early career teacher intent to remain in the teaching profession.…

  17. A Study on the Relationship between Teacher Self Efficacy and Burnout

    Science.gov (United States)

    Savas, Ahmet Cezmi; Bozgeyik, Yunus; Eser, Ismail

    2014-01-01

    The major purpose of the study was to examine the relationship between teacher self efficacy and burnout. In order to collect the related data, "Maslach Burnout Inventory" and "Teacher Sense of Efficacy Scale" were used. The sample of the study consisted of 163 randomly chosen teachers who worked in various primary and…

  18. Insect Repellents and Associated Personal Protection for a Reduction in Human Disease

    Science.gov (United States)

    2012-01-01

    motivated by West Nile virus and Lyme disease. The U.S. Environmental Protection Agency (EPA) lists 684 registered topical repellent products on their...and tick-borne diseases. In the United States, mosquitoes can transmit diseases like St. Louis encephalitis and West Nile virus . Ticks can transmit...and leishmaniasis during a study conducted in Colombia (Soto et al., 1995). Soldiers who wore permethrin-treated uniforms 24 h per day for 4.2 weeks had

  19. Water repellence assessment in humid mediterranean carbonated environments: influence of shrubland species

    Science.gov (United States)

    Oscar, Gonzalez-Pelayo; Vicente, Andreu; Luis, Rubio Jose; Carla Sofia, Ferreira; Dinis, Ferreira Antonio Jose

    2010-05-01

    The importance of natural or induced (fire) water repellence in terms of water redistribution in the soil profile, reduction in soil infiltration capacity and thus, in runoff magnification, is well established. Hydrophobicity has been identified around the world in different climatic conditions, land covers, soil and vegetation types. Regarding soil and vegetation, many studies are based on coarse acidic soils with pine forest, eucalyptus, deciduous trees, grassland, cropland, chaparral vegetation type, and lately in shrublands. However, few studies are related to shrubland in wet Mediterranean carbonated environments. This work is oriented to the study of soil water repellence in these environments by means of WDPT. The study was carried out in Podentes (Coimbra), central Portugal, on 4 ha of shrubland (mainly Quercus coccifera, Pistacia lentiscus and Arbutus unedo), developed on Umbric leptosol and Calcaric cambisol soil types (WRB). The WDPT was assessed depending on the shrubland type, slope orientation, soil depth (0-2 cm and 2-5 cm) and on different soil fractions ( Q. coccifera ≈ P. lentiscus; and depending on the orientation: NE > SW. Direct relationships were obtained between the soil organic matter content and the log WDPT on almost all the surface soil samples. The soil pH and carbonate content did not display correlation with soil water repellence. The different hydrophobic compounds generated by waxes and resins of the different shrubland types, which could be incorporated to the soil as binding agents, seem to be the explanation for the differences of the WDPT data. The patchy distribution of the vegetation rules the persistence of the natural soil water repellence, restraining water infiltration mainly by micropore flow, being then the soil hydrology controlled by the macropore flow, cracks and root system. Further research into soil organic matter quality in the finer soil aggregates could be necessary to confirm this link between the components

  20. Plasma treatment of polyester fabric to impart the water repellency property

    Indian Academy of Sciences (India)

    C J Jahagirdar; L B Tiwari

    2007-04-01

    Polyester fabric is treated with DCDMS solution by two methods: dipping the fabric directly in DCDMS solution for different intervals and dipping the fabric in DCDMS solution after its exposure into RF plasma chamber for different durations at optimized exposure power conditions. The physical properties of polyester fabric treated with DCDMS in the presence or absence of air plasma have been compared with control fabric. Different characterization techniques like scanning electron microscope, attenuated total reflectance-IR and Dataflash 100 colour measurement spectrophotometer are used to assess the surface morphology, composition and change in colour parameters. Water repellency property of both untreated and modified polyester fabric is studied using AATCC test method 39 (1971). The effectiveness of the water repellency property of modified polyester fabric is checked by repeated washing up to ten cycles.

  1. A practical geometrical comparison between free-repelled hydraulic jumps within inclined channels

    Institute of Scientific and Technical Information of China (English)

    John; Demetriou; Eugene; Retsinis

    2009-01-01

    In this experimental study a practical geometrical comparison between inclined (angle φ) free and repelled hydraulic jumps (the latter in non prismatic but abruptly expanding channels) is presented, analysed and discussed. For repelled hydraulic jumps a considerable parameter is the expansion ratio r (=channels’ width ratio), which here is changing from r =0.5 to r =0.7. The comparison is made with the free jump (in prismatic channel, r =1), in the same ranges of angles φ (0°≤φ≤8°) and Froude numbers (2≤Fr1≤8). A practical arithmetic example is presented to show the behavioral change of conjugate depths, lengths L and depths at 0.5L, in order to receive a comparison among all pertinent geometrical quantities. The present results may be useful for the hydraulic engineering when designing open channels.

  2. Comparative repellent properties of certain chemicals against mosquitoes, house flies and cockroaches using modified techniques.

    Science.gov (United States)

    Vartak, P H; Tungikar, V B; Sharma, R N

    1994-09-01

    Several terpenoids were assessed for their repellent/toxic properties against mosquitoes (Aedes aegypti), house flies (Musca domestica) and cockroaches (Periplaneta americana). Impregnated wide mesh netting was used in the case of the Dipterans, while treated filtered paper was employed for the bioassays with cockroaches. Persistence of the repellent chemicals was studied. Doses ranged from 5-20 gm/M2 for the Dipterans and 25-100 mg per 4 x 4 cm filter paper for the cockroaches. Dimethyl phthalate (DMP) offered the maximum protection of the chemicals tested against mosquitoes but was not so effective against house flies and cockroaches. Citral and Eugenol were effective against all the three test insects. Other test compounds afforded varying degrees of protection. Application strategy and utility of the findings are discussed.

  3. DIMENSIONAL STABILITY AND WATER REPELLENT EFFICIENCY MEASUREMENT OF CHEMICALLY MODIFIED TROPICAL LIGHT HARDWOOD

    Directory of Open Access Journals (Sweden)

    Md Saiful Islam,

    2012-01-01

    Full Text Available Chemical modification is an often-followed route to improve physical and mechanical properties of solid wood materials. In this study five kinds of tropical light hardwoods species, namely jelutong (Dyera costulata, terbulan (Endospermum diadenum, batai (Paraserianthes moluccana, rubberwood (Hevea brasiliensis, and pulai (Alstonia pneumatophora, were chemically modified with benzene diazonium salt to improve their dimensional stability and water repellent efficiency. The dimensional stability of treated samples in terms of volumetric swelling coefficient (S and anti-swelling-efficiency (ASE were found to improve with treatment. The water repellent efficiency (WRE values also seemed to improve considerably with treatment of wood samples. Furthermore, treated wood samples had lower water and moisture absorption compared to that of untreated ones.

  4. Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes.

    Science.gov (United States)

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

    Since ancient times, plant products were used in various aspects. However, their use against pests decreased when chemical products became developed. Recently, concerns increased with respect to public health and environmental security requiring detection of natural products that may be used against insect pests. In this study, 41 plant extracts and 11 oil mixtures were evaluated against the yellow fever mosquito, Aedes aegypti (Linnaeus), the malaria vector, Anopheles stephensi (Liston), and the filariasis and encephalitis vector, Culex quinquefasciatus (Say) (Diptera: Culicidae) using the skin of human volunteers to find out the protection time and repellency. The five most effective oils were those of Litsea (Litsea cubeba), Cajeput (Melaleuca leucadendron), Niaouli (Melaleuca quinquenervia), Violet (Viola odorata), and Catnip (Nepeta cataria), which induced a protection time of 8 h at the maximum and a 100% repellency against all three species. This effect needs, however, a peculiar formulation to fix them on the human skin.

  5. Hydrophobic duck feathers and their simulation on textile substrates for water repellent treatment

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yuyang; Chen Xianqiong; Xin, J H [Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hong Kong (China)], E-mail: liuxx751@umn.edu

    2008-12-01

    Inspired by the non-wetting phenomena of duck feathers, the water repellent property of duck feathers was studied at the nanoscale. The microstructures of the duck feather were investigated by a scanning electron microscope (SEM) imaging method through a step-by-step magnifying procedure. The SEM results show that duck feathers have a multi-scale structure and that this multi-scale structure as well as the preening oil are responsible for their super hydrophobic behavior. The microstructures of the duck feather were simulated on textile substrates using the biopolymer chitosan as building blocks through a novel surface solution precipitation (SSP) method, and then the textile substrates were further modified with a silicone compound to achieve low surface energy. The resultant textiles exhibit super water repellent properties, thus providing a simple bionic way to create super hydrophobic surfaces on soft substrates using flexible material as building blocks.

  6. Insect repellent plants traditional usage practices in the Ethiopian malaria epidemic-prone setting: an ethnobotanical survey

    Science.gov (United States)

    2014-01-01

    Background The usage of insect repellent plants (IRPs) is one of the centuries-old practices in Africa. In Ethiopia, malaria remains a leading cause of morbidity and mortality, subsequently the majority of people have a tendency to apply various plants as repellents to reduce or interrupt the biting activity of insects. Accordingly, this survey was undertaken to document and evaluate knowledge and usage practices of the local inhabitants on IRPs in the malaria epidemic-prone setting of Ethiopia. Methods Ethnobotanical survey was conducted between January and May 2013. Selected 309 household members were interviewed by administering pre-tested questionnaire on knowledge and usage practices of repellent plants, in Bechobore Kebele, Jimma Zone, Ethiopia. Results Overall, 70.2% (217/309) and 91.8% (199/217) of the respondents have had ample awareness and usage practices of repellent plants, respectively. Informants cited about twenty-two plant species as repellents and also indicated that these plants are useful(85.5%), accessible(86.8%), and affordable(83.9%) too. Residents mainly applying dried leaves [93.9% (187/199)] by means of burning/smouldering [98.9% (197/199)] with the traditional charcoal stove to repel insects, primarily mosquitoes. About 52.8% (105/199) of the informants using aproximately15g of dried plant-materials every day. A Chi-square analysis shows statistically a significant link between the knowledge on repellent plants and gender as well as average monthly income although not with the age of the respondents. Nevertheless, the repellent plant usage custom was not significantly associated with gender, monthly income, and age of the informants. Conclusion Though most of the people have had an adequate awareness still a sizable faction of society suffers with deprivation of IRPs knowledge and usage practices. Therefore, this study calls for more surveys to conserve the existing indigenous knowledge and cultural practices. It could lay the first stone

  7. Antecedent rainfall effects on the annual variability of water repellency in a patchy-vegetated Mediterranean hillslope (Almogía experimental field site, Southern Spain)

    Science.gov (United States)

    Damian Ruiz Sinoga, Jose; Francisco Martinez Murillo, Juan; Gabarron Galeote, Miguel Angel

    2010-05-01

    Several abiotic and biotic factors have been reported to describe runoff generation in Mediterranean hillslopes: e.g., slope gradient, micro-topography, vegetation pattern, soil water content, rock fragment size and distribution on soil surface, crusts, organic matter, etc. However, few investigations have been focused on the influence of soil repellency to water as runoff mechanisms. Two factors used to control water repellency in Mediterranean environments: soil moisture and organic matter content. There is a direct control of temporal rainfall distribution on soil water repellency: generally, it tends to increase during dry weather while it decreases or completely vanishes after heavy precipitation or during extended periods with high soil water contents. Also, water repellency used to be higher in soils with litter, roots, resins, waxes and other organic substances from some types of vegetation as they can be a source of hydrophobic substances, including some typical species of the Mediterranean scrublands. Studies in unburnt Mediterranean environments or burnt long time ago and more exactly of water repellency related to some vegetal shrub species are not very frequent in scientific literature. The aim of this study is to assess the influence of the rainfall variability in the water repellency of soils from a patchy-vegetated Mediterranean hillslope. The objectives are next: i) to analyze the effects of the rainfall variability on water repellency during one complete year; and ii) to determine the differences in water repellency of soils under a Mediterranean shrub specie (Cistus monspeliensis) and bare soil. The study site corresponds to one hillslope located in Montes de Málaga (South of Spain) under dry-Mediterranean climate. The hillslope was characterized by: southfacing, mean slope gradient of 27%, metamorphic geology (phyllites), patchy-vegetated pattern and sporadic grazing. The site was cultivated with cereal and disperse almond trees until the 1950s

  8. Study on the Repellent Activity of Plant Essectial Oils Against Latheticus oryzae Waterhouse%5种植物精油对长头谷盗的控制作用研究

    Institute of Scientific and Technical Information of China (English)

    郭钰; 曾玲; 梁广文

    2013-01-01

    选取小茴香、肉桂、丁香、辣椒和生姜精油,研究其对长头谷盗的控制作用.结果表明:(1)5种精油对长头谷盗均具有显著的驱避活性,其中丁香和生姜精油的5个试验浓度(1∶1、1∶10、1∶15、1∶20和1∶50)对长头谷盗的驱避效果最好,处理60h后,其驱避活性均达到Ⅴ级,72 h后,其驱避活性分别仍达到Ⅲ级和Ⅳ级;(2)小茴香、肉桂和丁香精油对长头谷盗有明显的触杀作用,其中处理最低浓度(1∶50)的肉桂时,长头谷盗的死亡率仍在60%以上;辣椒和生姜精油的触杀活性较弱,5个试验浓度对长头谷盗的死亡率几乎为零;(3)5种精油对长头谷盗均无明显的熏蒸作用.%Five plant essential oils of Foeniculum vulgare,Cinnamomum cassia,Syzygium aromaticum,Capsicum annuum and Zingiber officinale were used to investigate their repellent action,contact action and fumigation against Latheticas oryzae Waterhouse in this paper.The results showed that:(1) Five plant essential oils significantly repelled L.oryzae,and Syzygium aromaticum and Zingiber officinale with 5 tests concentration(1∶1,1 ∶ 10,1∶15,1∶20 and 1 ∶ 50) had the best repellent effects.60 h later,the repellency percentages was Ⅴ level,and 72 h later,the percentages were Ⅲ level and Ⅳ level,respectively.(2)Foeniculum vulgare,Cinnamomum cassia and Syzygium aromaticum essential oils could effectivelf kill L.oryzae adults.The contact toxicity of Foeniculum vulgare essential oil at 1∶ 50 concentration had no contact effect to L.oryzae,but the mortality of 1 ∶ 50 concentration was over 60%.However,the contact activity of Capsicum annuum and Zingiber officinale essential oils were weak,and the mortality of L.oryzae of five test concentrations were nearly zero.(3) In a word,all of the five kinds of essential oils couldn' t effectively fumigate L.oryzae adults.

  9. 硅烷改性混凝土防水和抗氯离子性能试验研究%Experimental study of the water repellency and chloride resistance of modified concrete with silane

    Institute of Scientific and Technical Information of China (English)

    张鹏; 赵铁军; 戴建国; 郭平功; Wittmann F H

    2011-01-01

    The water repellency and chloride resistance of modified concrete with silane without and with cracks have been investigated through neutron radiography test, water absorption test and chloride penetration test. The results indicate that the process of water penetration into mortar specimens without silane can be visualized distinctly by means of neutron radiography, while water in the modified mortar with silane cannot be observed by naked eyes. The hydrophobic films formed in the capillary pores from the added silane effectively restrain liquid water from penetrating into mortar, and consequently it results in decreasing water absorption to be only 13% of mortar without silane. The hydrolysis and polymerization reaction of silane in cementitious materials do not block the respirability of the capillary pores. Cracks are instantaneously filled with water once specimens without silane crack, and after that water will penetrate into the adjacent areas around the cracks. However, even when the modified specimens with silane crack up to 0. 3mm, there is no obvious water movement observed. The cracks from 0.1mm to 0.4mm hardly decrease the integral water repellency of modified concrete with silane. Due to the high water repellency of the modified concrete with silane it thus also has high resistance to chloride penetration with or without cracks. It is an effective method to improve the water repellency and chloride resistance and thus the durability of cement-based materials by modifying concrete with silane.%通过中子成像试验、吸水试验和氯离子侵蚀试验,研究无裂缝和带裂缝情况下硅烷改性混凝土的防水和抗氯离子侵蚀性能.试验结果表明,中子成像能够清晰观测未掺硅烷试件的快速吸水过程,而掺加硅烷后在毛细孔隙壁上形成的憎水膜能够有效抑制液态水分侵入,中子成像观测不到肉眼可见的水分前锋,吸水量降为未掺硅烷时的13%,显示出良好的防水性能.硅

  10. Influence of water-repellent treatment on the properties lime and lime pozzolan mortars

    Directory of Open Access Journals (Sweden)

    Fortes Revilla, C.

    2001-06-01

    Full Text Available The influence that water-repellent products can have on physical and micro-structural properties of lime mortars, and lime plus pozzolan mortars has been studied. Three water repellent products have been used. Mixes of the previously mentioned three water repellents plus a biocide product were also applied. Treatments make the total porosity and saturation coefficient of both mortars to decrease, while colorimetric coordinates bear little alteration. All treatments with water repellent products provided mortars with a hydrophobic property index close to 100%. Durability of such mortars has been also studied: salt crystallization test, frost-thaw and dry-wet cycles, as well as ultraviolet radiation test were carried out. Relationship between mortars behavior and their porosity and saturation coefficient were found.

    En el presente trabajo se ha estudiado la influencia de la aplicación de productos hidrofugantes a morteros de cal y morteros de cal y puzolana sobre sus propiedades físicas y microestructurales. Se han estudiado tres productos hidrofugantes. También han sido estudiados dichos productos junto con un biocida. La porosidad total y el coeficiente de saturación de ambos tipos de morteros se ve reducido por el efecto de los tratamientos mientras que las coordenadas colorimétricas se ven poco alteradas. Todos los tratamientos confieren un índice de hidrofobicidad a los morteros próximo al 100%. Asimismo, también se ha estudiado la durabilidad de dichos morteros frente a la cristalización de sales, hielo-deshielo, los ciclos de humedad-sequedad y radiaciones ultravioleta. Se relaciona el comportamiento de los morteros con su porosidad y el coeficiente de saturación.

  11. Water repellency of fly ash-enriched forest soils from eastern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, P.; Fleige, H.; Horn, R. [Forest Research Institute, Freiburg (Germany). Dept. of Soils & Environment

    2010-12-15

    Fly ash-enriched soils occur widely throughout the industrial regions of eastern Germany and in other heavily industrialized areas. A limited amount of research has suggested that fly ash enrichment alters the water repellency (WR) characteristics of soil. This study concentrates on the influence of fly ash enrichment on WR of forest soils with a focus on forest floor horizons (FFHs). The soils were a Technosol developed from pure lignite fly ash, FFHs with lignite fly ash, and FFHs without lignite fly ash enrichment. Three different methods were used to characterize soil WR. Additionally, carbon composition was determined using {sup 13}C-NMR spectra to interpret the influence of the organic matter. This study showed that the actual WR characteristics of undisturbed, fly ash-enriched soils can be explained in terms of the composition of soil organic matter, with the fly ash content playing only a minimal role. Regardless of the huge amounts of mainly mineral fly ash enrichment, all undisturbed FFHs were comparable in their WR characteristics and their carbon compositions, which were dominated by recently-formed organic substances. The pure fly ash deposit was strongly influenced by lignite remains, with the topsoil having a greater content of recent plant residues. Thus, the undisturbed topsoil was more repellent than the subsoil. When homogenized samples were used, we found a distinct effect of fly ash enrichment and structure on WR. Water repellency of the pure fly ash horizons did not differ distinctly, while the fly ash enrichment in the FFHs caused a significant reduction in WR. These results led to the assumption that water-repellent structures of the topsoils were probably the result of hydrophobic coatings of recently formed organic substances, whereby the initially high wettability of the mainly mineral, hydrophilic fly ash particles was reduced.

  12. Insecticidal and repellence activity of the essential oil of Pogostemon cablin against urban ants species.

    Science.gov (United States)

    Albuquerque, Elânia L D; Lima, Janaína K A; Souza, Felipe H O; Silva, Indira M A; Santos, Abraão A; Araújo, Ana Paula A; Blank, Arie F; Lima, Rafaely N; Alves, Péricles B; Bacci, Leandro

    2013-09-01

    Ants are highly abundant in neotropical regions, with certain species adapted to the urban environment, where they can cause damage to human health. The main method for controlling ants consists of using organosynthetic insecticides, which are potentially toxic to the environment. Essential plant oils are considered a viable alternative to the use of conventional insecticides. In this study, we analyze the bioinsecticidal activity and repellence of patchouli essential oil (Pogostemon cablin) against three species of urban ants: Camponotus melanoticus, Camponotus novograndensis, and Dorymyrmex thoracicus. The chemical composition of the essential oil was analyzed by GC-MS and GC-FID. The major compounds were patchoulol (36.6%) followed by α-bulnesene (13.95%), and α-guaiene (11.96%). Toxicity and repellency bioassays were performed using the essential oil over the ants, and mortality evaluations were performed at 4, 24, and 48 h after performing the bioassays. Mortality percentage of the ants on 7 μg/mg was on average 84%. The essential oil of P. cablin displayed toxicity against all three species of urban ants, with the lowest LD₅₀ being observed for D. thoracicus (2.02 μg oil/mg insect) after 48 h of exposure compared to C. melanoticus (2.34 μg oil/mg insect) and C. novogranadensis (2.95 μg oil/mg insect). The essential oil of P. cablin was strongly repellent to the three species of ants in all concentrations tested (0.01% and 1% v/v). Considering the potential toxicity and repellency of the P. cablin essential oil to the urban ants, future studies could investigate the practical application of this oil to control of this insects. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. A Comparison of Splash Erosion Behavior between Wettable and Water Repellent 'Soil' Particles

    Science.gov (United States)

    Ahn, S.; Hamlett, C. A.; Doerr, S.; Bryant, R.; Shirtcliffe, N.; McHale, G.; Newton, M.

    2011-12-01

    Wildfires remove vegetation and litter cover and expose soil surfaces to particle detachment by rain splash. This can serve as an agent of initial soil modification and erosion in the post-fire period. Splash behavior is mainly determined by the kinetic energy delivered by impacting water drops (erosivity), and the detachability (erodibility) of surface particles, affected by their size, aggregate stability and shear strength. Soil detachability may also be affected by water repellency (hydrophobicity). This soil characteristic is influenced by wildfire and may affect splash behavior by reducing capillary forces between particles. Previous work on splash behavior using cumulative drop impact reported larger ejection droplets and lower and shorter trajectories of ejections for water repellent soil compared with wettable soil (Terry and Shakesby 1993). A water film generated by delayed infiltration on water repellent soil was suggested to account for the difference. This study compares the trajectories of ejected wettable and hydrophobic model soil particles from single water drop impacts in order to isolate the effect of soil particle wettability on splash erosion behavior. Acid-washed (wettable) and hydrophobized (water repellent) glass beads used as model soil particles were held in an array within a squat cylinder of 1.5 cm diameter in the centre of a 20 cm diameter disk covered with a viscous adhesive film. A distilled water drop (20μL) was released 40 cm above the centre of the array and the resultant impact was recorded at 976 frames per second using a high speed video camera. The populations of, and distances travelled by, the particles were measured for three arrays of bead sizes within the range (180-400 μm). Three to five replications were made for each test. The trajectory of each ejected particle was traced on video frames and corrected for the actual distance and direction of travel measured from the adhesive film. The initial velocity and ejecting

  14. Seasonal changes in soil water repellency and their effect on soil CO2 fluxes

    Science.gov (United States)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil water repellency (SWR) is a seasonally variable phenomenon controlled by moisture content and at the same time a regulator of the distribution and conductivity of water in the soil. The distribution and availability of water in soil is also an important factor for microbial activity, decomposition of soil organic matter and exchange of gases like CO2 and CH4 between the soil and the atmosphere. It has been therefore hypothesised that SWR by restricting water availability in soil can affect the production and the transport of CO2 in the soil and between the soil and the atmosphere. This study investigates the effect of seasonal changes in soil moisture and water repellency on CO2 fluxes from soil. The study was conducted for 3 year at four grassland and pine forest sites in the UK with contrasting precipitation. The results show the temporal changes in soil moisture content and SWR are affected by rainfall intensity and the length of dry periods between the storms. Soils exposed to very high annual rainfall (>1200mm) can still exhibit high levels of SWR for relatively long periods of time. The spatial variation in soil moisture resulting from SWR affects soil CO2 fluxes, but the most profound effect is visible during and immediately after the rainfall events. Keywords: soil water repellency, CO2 flux, hydrophobicity, preferential flow, gas exchange, rainfall

  15. Electronic Cigarettes Efficacy and Safety at 12 Months: Cohort Study.

    Directory of Open Access Journals (Sweden)

    Lamberto Manzoli

    Full Text Available To evaluate the safety and efficacy as a tool of smoking cessation of electronic cigarettes (e-cigarettes, directly comparing users of e-cigarettes only, smokers of tobacco cigarettes only, and smokers of both.Prospective cohort study. Final results are expected in 2019, but given the urgency of data to support policies on electronic smoking, we report the results of the 12-month follow-up.Direct contact and structured questionnaires by phone or via internet.Adults (30-75 years were included if they were smokers of ≥1 tobacco cigarette/day (tobacco smokers, users of any type of e-cigarettes, inhaling ≥50 puffs weekly (e-smokers, or smokers of both tobacco and e-cigarettes (dual smokers. Carbon monoxide levels were tested in a sample of those declaring tobacco smoking abstinence.Sustained smoking abstinence from tobacco smoking at 12 months, reduction in the number of tobacco cigarettes smoked daily.We used linear and logistic regression, with region as cluster unit.Follow-up data were available for 236 e-smokers, 491 tobacco smokers, and 232 dual smokers (overall response rate 70.8%. All e-smokers were tobacco ex-smokers. At 12 months, 61.9% of the e-smokers were still abstinent from tobacco smoking; 20.6% of the tobacco smokers and 22.0% of the dual smokers achieved tobacco abstinence. Adjusting for potential confounders, tobacco smoking abstinence or cessation remained significantly more likely among e-smokers (adjusted OR 5.19; 95% CI: 3.35-8.02, whereas adding e-cigarettes to tobacco smoking did not enhance the likelihood of quitting tobacco and did not reduce tobacco cigarette consumption. E-smokers showed a minimal but significantly higher increase in self-rated health than other smokers. Non significant differences were found in self-reported serious adverse events (eleven overall.Adding e-cigarettes to tobacco smoking did not facilitate smoking cessation or reduction. If e-cigarette safety will be confirmed, however, the use of e

  16. Does interprofessional simulation increase self-efficacy: a comparative study

    OpenAIRE

    Watters, Colm; Reedy, Gabriel; Ross, Alastair; Morgan, Nicola J; Handslip, Rhodri; Jaye, Peter

    2015-01-01

    Objectives In this work, we have compared uniprofessional and interprofessional versions of a simulation education intervention, in an attempt to understand more about whether it improves trainees’ self-efficacy. \\ud \\ud \\ud Background Interprofessionalism has been climbing the healthcare agenda for over 50 years. Simulation education attempts to create an environment for healthcare professionals to learn, without potential safety risks for patients. Integrating simulation and interprofession...

  17. A Survey Study of Chinese In-Service Teachers' Self-Efficacy about Inclusive Education

    Science.gov (United States)

    Wang, Mian; Zan, Fei; Liu, Jiaqiu; Liu, Chunling; Sharma, Umesh

    2012-01-01

    A survey study was conducted to a total of 323 in-service teachers (110 special education teachers and 213 general education teachers) in Shanghai regarding their self-efficacy and concerns about inclusive education. Multivariate analysis results reveal that special teachers have significantly higher self-efficacy about inclusive education than…

  18. Academic Oral Presentation Self-Efficacy: A Cross-Sectional Interdisciplinary Comparative Study

    Science.gov (United States)

    Amirian, Seyed Mohammad Reza; Tavakoli, Elaheh

    2016-01-01

    Despite the significant role of oral presentation in the academic context, many university students evade opportunities for participation due to low self-efficacy. The present study has been conducted to compare oral presentation self-efficacy of English as a Foreign Language (EFL) learners with undergraduates and postgraduates of Non-EFL majors,…

  19. Organizational Structure, Collegial Trust, and College Faculty Teaching Efficacy: A Case Study

    Science.gov (United States)

    Okpogba, Desmond

    2011-01-01

    The purpose of this mixed-method study was to explore the relationship between faculty self-efficacy, organizational structure, and collegial trust. The concepts of teacher self-efficacy, organizational structure, and collegial trust were used to investigate any possible empirical relationships existing between these variables in a private,…

  20. Agricultural Education Perceived Teacher Self-Efficacy: A Descriptive Study of Beginning Agricultural Education Teachers

    Science.gov (United States)

    Wolf, Kattlyn J.

    2011-01-01

    The purpose of this study was to describe beginning agriculture teachers' perceived agricultural education teacher self-efficacy. Additionally, the researcher sought to describe the relationship among teachers' demographic characteristics and their agricultural education teacher self-efficacy. An instrument specific to agricultural education was…

  1. A Survey Study of Chinese In-Service Teachers' Self-Efficacy about Inclusive Education

    Science.gov (United States)

    Wang, Mian; Zan, Fei; Liu, Jiaqiu; Liu, Chunling; Sharma, Umesh

    2012-01-01

    A survey study was conducted to a total of 323 in-service teachers (110 special education teachers and 213 general education teachers) in Shanghai regarding their self-efficacy and concerns about inclusive education. Multivariate analysis results reveal that special teachers have significantly higher self-efficacy about inclusive education than…

  2. Developing Teaching Self-Efficacy in Research Institutions: A Study of Award-Winning Professors

    Science.gov (United States)

    Morris, David B.; Usher, Ellen L.

    2011-01-01

    The purpose of this study was to assess the sources of award-wining research professors' (six women; six men) teaching self-efficacy through the framework of Bandura's (1986) social cognitive theory. Semi-structured interviews revealed that mastery experiences and social persuasions were particularly influential sources of self-efficacy and that…

  3. Turkish Version of the Principals' Sense of Efficacy Scale: Validity and Reliability Study

    Science.gov (United States)

    Isik, Ayse Negis; Derinbay, Deniz

    2015-01-01

    Problem Statement: Principals are known as important actors in effective schools. So it is important to know which variables influence principals' success. One of these predictors can be self-efficacy. However, there is very few research about principals' sense of efficacy. Purpose of the Study: The purpose of this research was to test the…

  4. Using Mathematics in Teaching Science Self-Efficacy Scale--UMSSS: A Validity and Reliability Study

    Science.gov (United States)

    Can, Bilge Taskin; Gunhan, Berna Canturk; Erdal, Sevinc Ongel

    2012-01-01

    In this study, an instrument, Using Mathematics in Science Self-efficacy Scale (UMSSS), was developed in order to determine preservice science teachers' self-efficacy toward the use of mathematics in their lessons. Data gathered from 250 preservice science teachers were used for Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis…

  5. Education for Sustainability: A Case Study of Preservice Primary Teachers' Knowledge and Efficacy

    Science.gov (United States)

    Effeney, Gerard; Davis, Julie

    2013-01-01

    This study investigated the relationships between knowledge and efficacy for teaching sustainability in a sample of 266 pre-service primary teachers at a large, metropolitan university in Australia. A survey gathered information about the participant's attitudes and self-efficacy for education for sustainability, along with their perceived and…

  6. Organizational Structure, Collegial Trust, and College Faculty Teaching Efficacy: A Case Study

    Science.gov (United States)

    Okpogba, Desmond

    2011-01-01

    The purpose of this mixed-method study was to explore the relationship between faculty self-efficacy, organizational structure, and collegial trust. The concepts of teacher self-efficacy, organizational structure, and collegial trust were used to investigate any possible empirical relationships existing between these variables in a private,…

  7. Self-Efficacy and Creative Productivity: Three Studies of above Average Ability Children.

    Science.gov (United States)

    Schack, Gina D.; And Others

    1991-01-01

    Three studies involving a total of 918 students of above average ability in grades 3 through 8 confirm the importance of self-efficacy in students' decisions to initiate creative productivity and reinforce the value of performance accomplishments for increasing self-efficacy and creative productivity. (SLD)

  8. Loss and gain cycles? A longitudinal study about burnout, engagement and self-efficacy

    Directory of Open Access Journals (Sweden)

    Susana Llorens-Gumbau

    2014-06-01

    Full Text Available The present longitudinal study (two waves, conducted on a population of 274 secondary-school teachers, expands on previous research on burnout and work engagement. Accordingly, the effect of organizational factors (obstacles, facilitators as well as personal resources (self-efficacy on burnout and engagement is tested longitudinally following the Social Cognitive Theory. More specifically, we test the loss and gain cycles, and reciprocal relationships concerning burnout, engagement, and self-efficacy over time. Four questions are addressed: (1 Are obstacles positively related to burnout and work self-efficacy over time? (2 Are facilitators positively related to engagement and self-efficacy over time? (3 Is work self-efficacy negatively related to burnout and obstacles over time? and (4 Is work self-efficacy positively related to engagement and facilitators over time? The results of a hard-copy survey carried out at two waves (8 months between the two times, which were computed on Structural Equation Modeling show that obstacles are positively related to burnout, which in turn is positively related to self-efficacy over time. Likewise, facilitators are positively related to engagement and self-efficacy, which in turn is positively related to facilitators over time. These findings suggest a positive gain cycle in which self-efficacy plays a central role.

  9. Vegetation cover and land use impacts on soil water repellency in an Urban Park located in Vilnius, Lithuania

    Science.gov (United States)

    Pereira, Paulo; Cerda, Artemi

    2015-04-01

    It is strongly recognized that vegetation cover, land use have important impacts on the degree of soil water repellency (SWR). Soil water repellency is a natural property of soils, but can be induced by natural and anthropogenic disturbances as fire and soil tillage (Doerr et al., 2000; Urbanek et al., 2007; Mataix-Solera et al., 2014). Urban parks are areas where soils have a strong human impact, with implications on their hydrological properties. The aim of this work is to study the impact of different vegetations cover and urban soils impact on SWR and the relation to other soil variables as pH, Electrical Conductivity (EC) and soil organic matter (SOM) in an urban park. The study area is located in Vilnius city (54°.68' N, 25°.25' E). It was collected 15 soil samples under different vegetation cover as Pine (Pinus Sylvestris), Birch (Alnus glutinosa), Penduculate Oak (Quercus robur), Platanus (Platanus orientalis) and other human disturbed areas as forest trails and soils collected from human planted grass. Soils were taken to the laboratory, air-dried at room temperature and sieved with the 3600 (extremely water repellent). The results showed significant differences among the different vegetation cover (Kruskal-Wallis H=20.64, pgrass were significantly higher than Platanus soil. The soils from Pine, Birch, Penduculate Oak, forest trails and planted grass were majorly severely water repellent, while Platanus soils were mostly strong water repellent. Soil water repellency of Pine soils had a significant negative correlation with pH (-0.52, ppH (-0.88, ppH, EC and SOM. Acknowledgments POSTFIRE (Soil quality, erosion control and plant cover recovery under different post-fire management scenarios, CGL2013-47862-C2-1-R), funded by the Spanish Ministry of Economy and Competitiveness; Fuegored; RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES

  10. Organic compounds characteristics associated with heat-induced increases of water repellency in Australian eucalypt forest soils

    Science.gov (United States)

    Atanassova, Irena; Doerr, Stefan H.

    2010-05-01

    Ground surface heating during wildfires often leads to increased water repellency in soils. The effect of elevated soil temperature on water repellency has been investigated in many laboratory-based studies and temperature thresholds for increases in, and destruction of, water repellency have been established. However, little is known about the changes in organic compounds patterns and their chemical structure that associated with these changes. Here we report on the characterisation of the chemical changes of organic compounds associated with heat-induced increases in water repellency in Eucalypt soils of different repellency levels. Fires are very common in eucalypt forest environments and soils under eucalypt species exhibit one of the most severe repellency levels, providing an ideal study case. Three SE Australian eucalypt forest soils from different locations (two sands and one sandy loam) were heated in the laboratory for 10 min at 300° C. Laboratory heating resulted in extreme repellency in the three soils studied. Heated and unheated control samples were then extracted by accelerated solvent extraction (ASE) with iso-propanol/ammonia mixture (IPA/NH3 95:5). Extraction led to the elimination of any water repellency present both in the original (heated) and the control samples. Organic compounds in the IPA/NH3 solvent were measured in extracts of increasing polarity in order to solubilise the residue. Before heating, the total solvent extracts from the soils with sandy texture were dominated by n-alkanols, terpenoids, C16 acid, C29 alkane, β-sitosterol and polar compounds such as glycerol, monosaccharides and glycosides. Fatty acids with chain length over C20 were detected in the sandy soils, while the soil of heavier texture (sandy loam) lacked longer than C20 fatty acids and had lower concentrations of alkanols (exceeding C26 chain lenght) and alkanes (C29, C31). Alkane patterns were characterized by the predominance of C21 - C31 homologues with a

  11. Excito-repellency effect of deltamethrin on triatomines under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Diotaiuti Liléia

    2000-01-01

    Full Text Available This work demonstrates that deltamethrin in low doses produces an excito-repellency effect on triatomines, as already observed for mosquitoes. A wooden box covered with a cloth impregnated with deltamethrin at doses of 2.5 and 5mg ai/m² was utilized for the experiment. The triatomine species studied were Triatoma infestans, Panstrongylus megistus, Rhodnius neglectus and Triatoma sordida. Adults were released in one of the sides of the box and their position was noted in subsequent periods. The observations were realized on the day the cloth was impregnated and subsequently repeated at 30 and 60 days for T. sordida; on day 120, the remaining species were included. Insect mortality and attempts at flight from the box were also observed. Excito-repellency was evident for all species and doses up to day 120. The only species that attempted to fly was P. megistus. The excito-repellency effect may be considered as an additional advantage to the insecticide power, as it should be able to prevent the installation of new colonies by females that fly into the homes, and at the moment of the spraying, it should promote the flushing out of triatomines from the wall crevices and from other shelters.

  12. Contact toxicity and repellency of the essential oil from Mentha haplocalyx Briq. against Lasioderma serricorne.

    Science.gov (United States)

    Zhang, Wen-Juan; Yang, Kai; You, Chun-Xue; Wang, Cheng-Fang; Geng, Zhu-Feng; Su, Yang; Wang, Ying; Du, Shu-Shan; Deng, Zhi-Wei

    2015-05-01

    The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Mentha haplocalyx was investigated by GC-FID and GC/MS analyses. In sum, 23 components, representing 92.88% of the total oil composition, were identified, and the main compounds were found to be menthol (59.71%), menthyl acetate (7.83%), limonene (6.98%), and menthone (4.44%). By bioassay-guided fractionation (contact toxicity), three compounds were obtained from the essential oil and identified as menthol, menthyl acetate, and limonene. The essential oil and the three isolated compounds exhibited potent contact toxicity against Lasioderma serricorne adults, with LD50 values of 16.5, 7.91, 5.96, and 13.7 μg/adult, respectively. Moreover, the oil and its isolated compounds also exhibited strong repellency against L. serricorne adults. At the lower concentrations tested and at 2 h after exposure, menthol showed even significantly stronger repellency than the positive control DEET. The study revealed that the bioactivity properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components, which indicates that the M. haplocalyx oil and its isolated compounds have potential for the development as natural insecticides and/or repellents to control insects in stored grains and traditional Chinese medicinal materials.

  13. Quantitative assessment to the structural basis of water repellency in natural and technical surfaces.

    Science.gov (United States)

    Wagner, P; Fürstner, R; Barthlott, W; Neinhuis, C

    2003-04-01

    Many plant surfaces are water-repellent because of a complex 3-dimensional microstructure of the epidermal cells (papillae) and a superimposed layer of hydrophobic wax crystals. Due to its surface tension, water does not spread on such surfaces but forms spherical droplets that lie only on the tips of the microstructures. Studying six species with heavily microstructured surfaces by a new type of confocal light microscopy, the number, height, and average distance of papillae per unit area were measured. These measurements were combined with those of an atomic force microscope which was used to measure the exposed area of the fine-structure on individual papillae. According to calculations based upon these measurements, roughening results in a reduction of the contact area of more than 95% compared with the projected area of a water droplet. By applying water/methanol solutions of decreasing surface tension to a selection of 33 water-repellent species showing different types of surface structures, the critical value at which wetting occurs was determined. The results impressively demonstrated the importance of roughening on different length scales for water-repellency, since extremely papillose surfaces, having an additional wax layer, are able to resist up to 70% methanol. Surfaces that lack papillae or similar structures on the same length scale are much more easily wetted.

  14. Effects of Revolution on soil wetting, turf performance and nitrogen efficiency of a fairway prone to soil water repellency

    NARCIS (Netherlands)

    Oostindie, K.; Dekker, L.W.; Geissen, V.; Ritsema, C.J.

    2013-01-01

    This study reports on the effects of applications of the surfactant Revolution on soil wetting and turf performance of fairway 10 of the Rosendaelsche Golfclub, located near Arnhem, The Netherlands. In addition, the influence of Revolution on soil water repellency and the nitrogen contents in grass

  15. The potential attractant or repellent effects of different water types on oviposition in Aedes aegypti L. (Dipt., Culicidae)

    NARCIS (Netherlands)

    Navarro, D.M.A.F.; Oliveira, de P.E.S.; Potting, R.P.J.; Brito, A.C.; Fital, S.J.F.; Goulart Sant Ana, A.E.

    2003-01-01

    The selection of oviposition sites by the yellow-fever mosquito, Aedes aegypti , was studied in the laboratory. The repellent or attractant effects of salinity and the presence of bacteria in water collected from a local community on the Brazilian coast were investigated. Water contaminated with

  16. The potential attractant or repellent effects of different water types on oviposition in Aedes aegypti L. (Dipt., Culicidae)

    NARCIS (Netherlands)

    Navarro, D.M.A.F.; Oliveira, de P.E.S.; Potting, R.P.J.; Brito, A.C.; Fital, S.J.F.; Goulart Sant Ana, A.E.

    2003-01-01

    The selection of oviposition sites by the yellow-fever mosquito, Aedes aegypti , was studied in the laboratory. The repellent or attractant effects of salinity and the presence of bacteria in water collected from a local community on the Brazilian coast were investigated. Water contaminated with bac

  17. Water repellency in the rhizosphere of maize: measurements and modelling

    Science.gov (United States)

    Ahmed, Mutez; Kroener, Eva; Carminati, Andrea

    2016-04-01

    Although maize roots have been extensively studied, there is limited information on the effect of root exudates on the hydraulic properties of maize rhizosphere. Recent experiments suggested that the mucilaginous fraction of root exudates may cause water repellency of the rhizosphere. Our objectives were: 1) to investigate whether maize rhizosphere turns hydrophobic after drying and subsequent rewetting; 2) to develop a new method to collect root mucilage and test whether maize mucilage is hydrophobic; and 3) to find a quantitative relation between rhizosphere rewetting, particle size, soil matric potential and mucilage concentration. Maize plants were grown in aluminum containers filled with a sandy soil. When the plants were three-weeks-old, the soil was let dry and then it was irrigated. The soil water content during irrigation was imaged using neutron radiography. In a parallel experiment, ten maize plants were grown in sandy soil for five weeks. Mucilage was collected from young brace roots using a new developed method. Mucilage was placed on glass slides and let dry. The contact angle was measured with the sessile drop method for varying mucilage concentration. Additionally, we used neutron radiography to perform capillary rise experiments in soils of varying particle size mixed with maize mucilage. We then used a pore-network model in which mucilage was randomly distributed in a cubic lattice. The general idea was that rewetting of a pore is impeded when the concentration of mucilage on the pore surface (g cm-2) is higher than a given threshold value. The threshold value depended on soil matric potential, pore radius and contact angle. Then, we randomly distributed mucilage in the pore network and we calculated the percolation of water across a cubic lattice for varying soil particle size, mucilage concentration and matric potential. Our results showed that: 1) the rhizosphere of maize stayed temporarily dry after irrigation; 2) mucilage became water

  18. Approaches to characterize the degree of water repellency

    Science.gov (United States)

    Letey, J.; Carrillo, M. L. K.; Pang, X. P.

    2000-05-01

    Measurement techniques that quantify the degree of soil water repellency are important for research and for the communication of research findings. The water drop penetration time (WDPT) is a commonly used measurement. If a water drop does not enter the soil spontaneously, the soil-water contact angle is greater than 90° and the soil is considered to be water repellent. The time for the drop to enter the soil (WDPT) provides an indication of the stability of the repellency. The liquid-air surface tension of an aqueous ethanol concentration series that enters the soil in approximately 5 s is identified as the ninety degree (ND) surface tension, γND, of the soil. The γND number can be used to calculate the solid-air surface tension, γs, by γs= γND/4. The water-soil contact angle can also be calculated from the γs value by the relationship cos θ=[(γ ND/γ w) 1/2-1], where θ is the contact angle and γw the water-air surface tension. The water entry pressure, hp, which is a function of both the soil water repellency and pore size, is an important parameter for predicting infiltration and the stability of water flow in the field. Measurements of WDPT, γND, and hp provide a complete characterization of the degree of water repellency.

  19. Efficacy beliefs as a moderator of the impact of work-related stressors: a multilevel study.

    Science.gov (United States)

    Jex, S M; Bliese, P D

    1999-06-01

    This study built on previous exploratory research (S. M. Jex & D. M. Gudanowski, 1992) that examined both self-efficacy and collective efficacy as moderators of stressor-strain relations. Based on survey data collected from 2,273 U.S. Army soldiers representing 36 companies, it was found that both self- and collective efficacy moderated the relationship between stressors and strains. Multilevel random coefficient model results revealed that respondents with strong self-efficacy reacted less negatively in terms of psychological and physical strain to long work hours and work overload than did those reporting low levels of efficacy. In addition, respondents with high levels of self-efficacy responded more positively in terms of job satisfaction to tasks with high significance than did those with low efficacy. The results also revealed that group-level collective efficacy moderated the relationship between work overload and job satisfaction and between task significance and organizational commitment. Limitations of the study and implications of these findings are discussed.

  20. Insecticide and Repellent Mixture Pour-On Protects Cattle against Animal Trypanosomosis

    Science.gov (United States)

    Abdoulmoumini, Mamoudou; Zoli, Andre; Cene, Bylah; Adakal, Hassane; Bouyer, Jérémy

    2016-01-01

    Background African animal trypanosomosis (AAT), transmitted by tsetse flies and tick-borne diseases are the main constraints to livestock production in sub-Saharan Africa. Vector control methods such as pour-on offer individual protection against ticks but not against tsetse so far, for which protection has always been communal, through a reduction of their density. The latter requires the treatment of a large part of the herd in a given landscape and is not instantaneous. Methodology/Principal Findings Two prospective surveys were conducted to evaluate the efficacy and persistence of a pour-on formulation composed of cypermetrhin, chlorpyrifos, piperonyl butoxid and citronella (Vectoclor, CEVA Santé Animal). In experimental conditions, tsetse flies were exposed to treated and control cattle. Flies knockdown and engorgement rates were determined and the product persistence was assessed as the time for these parameters to drop below 50% (T50). T50 was 37 days (95%CI: [33–41] days) and 46 days (95%CI: [39–56] days) for the knockdown and engorgement rates respectively. In field conditions, two cattle herds were monitored following a case-control experimental design, in the Adamaoua region of Cameroon. One herd was treated once with Vectoclor pour-on (treated group) and the second used as a control group (not treated). Ticks infestation rate, trypanosomosis prevalence and packed-cell volume were measured over the two months following treatment. The treatment was highly effective against ticks with a complete elimination three days after application in the treated group. Trypanosomosis prevalence was also significantly reduced during the study (by 4, P<0.001) and PCV of the treated group increased significantly in the same time (P<0.001), contrary to the control group. Conclusions/Significance The protection of this new pour-on against tsetse bites and trypanosomosis is demonstrated here for the first time. Moreover, this insecticide and repellent mixture offer a

  1. Prior Self-Efficacy Interacts with Experiential Valence to Influence Self-Efficacy among Engineering Students: An Experimental Study

    Science.gov (United States)

    Chang, Yevvon Yi-Chi; Chiou, Wen-Bin

    2017-01-01

    Self-efficacy toward science learning has been shown to play a crucial role in determining students' motivation and achievements. Social cognitive theory proposes that positive and negative task outcomes affect mastery experiences from which self-efficacy develops. The current research examined whether prior level of self-efficacy would serve as a…

  2. Multi-function oxidases are responsible for the synergistic interactions occurring between repellents and insecticides in mosquitoes

    Directory of Open Access Journals (Sweden)

    Duchon Stéphane

    2009-04-01

    Full Text Available Abstract Background With the spread of pyrethroid resistance in mosquitoes, the combination of an insecticide (carbamate or organophosphate with a repellent (DEET is considered as a promising alternative strategy for the treatment of mosquito nets and other relevant materials. The efficacy of these mixtures comes from the fact that they reproduce pyrethroid features and that positive interactions occur between insecticides and repellent. To better understand the mechanisms involved and assess the impact of detoxifying enzymes (oxidases and esterases in these interactions, bioassays were carried out in the laboratory against the main dengue vector Aedes aegypti. Methods Topical applications of DEET and propoxur (carbamate, used alone or as a mixture, were carried out on female mosquitoes, using inhibitors of the two main detoxification pathways in the insect. PBO, an inhibitor of multi-function oxidases, and DEF, an inhibitor of esterases, were applied one hour prior to the main treatment. Results Results showed that synergism between DEET and propoxur disappeared in the presence of PBO but not with DEF. This suggests that oxidases, contrary to esterases, play a key role in the interactions occurring between DEET and cholinesterase inhibitors in mosquitoes. Conclusion These findings are of great interest for the implementation of "combination nets" in the field. They support the need to combine insecticide with repellent to overcome insecticide resistance in mosquitoes of public health importance.

  3. Larvicidal and repellent activities ofSida acuta Burm. F. (Family:Malvaceae) against three important vector mosquitoes

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan

    2010-01-01

    Objective:To determine the larvicidal and repellent activities ofSida acuta Burm. F. (Family: Malvaceae)extract against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi. Methods: Twenty five late III instar larve of three mosquito species were exposed to various concentrations (15-90 mg/L) and were assayed in the laboratory by using the protocol ofWHO 2005; the24 h LC50 values of theSida acuta leaf extract was determined following Probit analysis. The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0, 2.5 and5.0mg/cm2 under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes withLC50values ranging between38 to48 mg/L. The crude extract had strong repellent action against three species of mosquitoes as it provided100%protection againstAnopheles stephensi for 180min followed byAedes aegypti (150 min) andCulex quinquefasciatus (120 min).Conclusions:From the results it can be concluded the crude extract ofSida acuta was an excellent potential for controllingCulex quinquefasciatus, Aedes aegypti andAnopleles stephensi mosquitoes.

  4. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan M; Mathivanan T; Elumalai K; Krishnappa K; Anandan A

    2011-01-01

    Objective: To determine the ovicidal and repellent activities of methanol leaf extract ofErvatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods: The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions.Results:The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae.aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions: From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes.

  5. Encapsulation of Citronellal from Citronella Oil using β-Cyclodextrin and Its Application as Mosquito (Aedes aegypti) Repellent

    Science.gov (United States)

    Pujiastuti, A.; Cahyono, E.; Sumarni, W.

    2017-04-01

    Mosquito (Aedes aegypti) is a threat to human health due to its capability to spread dengue fever. Citronellal in citronella oil is one ofnatural active compound that has repellent activity. Essential oil is a sensitive material whichiseasy to degrade. Encapsulation is coating technology use to avoid essential oil from degradation problems. β-Cyclodextrin is frequently used as acoating material in encapsulation. The aims of this study wereto prepare the citronellal encapsulation and to evaluate its control-released and repellency. In this study, encapsulated citronellal was prepared using 83.65% citronellal and encapsulation were prepared with the theemulsion-based method and dried using freeze-dryer. The best-controlled release was performed in citronellal encapsulate with a weight ratio of 1:1 (citronellal : β-Cyclodextrin). The morphology of encapsulated citronellal was analyzed using SEM. SEM result showed it has three dimensions random shape and agglomerate in some part with thebrighter spot. Citronellal encapsulate showed the highest repellent effect at 84,67% for 5 minutes in mosquito repellency test although it has lower result compared with citronellal inliquid form.

  6. Emotional energy, work self-efficacy, and perceived similarity during the Mars 520 study

    OpenAIRE

    Šolcová, I. (Iva); Gushin, V. (1); Vinokhodova, A.; Lukavský, J. (Jiří)

    2013-01-01

    The objective of the present research was to study the dynamics of changes in emotional energy, work self-efficacy, and perceived similarity in the crew of the Mars 520 experimental study that simulated traveling to Mars, orbiting it, landing, and returning to Earth. The study comprised six volunteers, all men, between 27–38 yr of age. During the simulation, measures of emotional energy, work self-efficacy, and perceived similarity were repeated every month. Emotional energy, work self-effica...

  7. Coating for Nano Super Soil-repellency of Cashmere Fabric

    Institute of Scientific and Technical Information of China (English)

    WANG Jin-mei; ZHU Chang-chun

    2005-01-01

    The nano-size metal oxide was prepared by the single-disperse technique on liquid phase, and formed sol clusters, its uniform film was covered on the surface of cashmere fibers by coating, and it had good oil repellency and water repellency. The results of IR(infrared) Spectrometer analysis revealed: The nano material combines through the strong bonds with the surface of cashmere fibers by the live groups.These analyses by SEM techniques showed that the nano material was distributed on the fiber surface even, and the nano material formed the strong peak of the regular crystal phase structure using the X-Ray Diffractometry (XRD) to analysis the fabric. The optimum techniques were selected by a series of experiments, coated cashmere fabric not only has preserved original properties of softness and comfort,but also has good properties of Bi-repellency function.Therefore, the technique will have potential application in engineers.

  8. Shared Relationship Efficacy of Dyad Can Increase Life Satisfaction in Close Relationships: Multilevel Study.

    Directory of Open Access Journals (Sweden)

    Ryosuke Asano

    Full Text Available Characteristics of relationship itself play an important role in determining well-being of individuals who participate in the relationship. We used efficacy expectations mutually shared between close friends or romantic partners as a characteristic of relationship and investigated its impact on their life satisfaction. In Study 1, we conducted a cross-sectional study among 137 pairs of close same-sex friends to test whether the efficacy expectations shared between friends are associated with levels of life satisfaction. In Study 2, we conducted a longitudinal study among 114 heterosexual romantic couples to test predictive validity of the efficacy expectations shared between couples predict levels of life satisfaction 2 month later. In both studies we found a consistent result that as degrees of the efficacy expectations shared between individuals in a relationship increased, the degree of their life satisfaction also increased. Underlying mechanisms that explain how characteristics of relationship itself increase life satisfaction are discussed.

  9. Repellent effect of alphacypermethrin-treated netting against Bemisia tabaci (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Martin, T; Kamal, A; Gogo, E; Saidi, M; Delétré, E; Bonafos, R; Simon, S; Ngouajio, M

    2014-04-01

    For > 20 yr, Bemisia tabaci Gennadius persists as a begomovirus vector and is a serious problem in tomato production in many parts of the world. In tropical countries, the use of netting to protect horticultural crops has proven to be an effective and sustainable tool against Lepidoptera but not against small insects. This study evaluated the repellent effect of AgroNet 0.9T, a 0.9-mm pore diameter and 40-mesh size netting treated with alphacypermethrin insecticide against B. tabaci. This pyrethroid insecticide is known to have toxic and repellent effects against mosquitoes and has been used for treatment of mosquito nets. Two nontreated netting materials were used as control: AgroNet 0.9NT with 0.9-mm pore diameter and 40-mesh size and AgroNet 0.4NT with 0.4-mm pore diameter and 80-mesh size. The behavior of B. tabaci and its parasitoid Encarsia formosa Gahan as they progressed through the treated netting was studied in the laboratory in choice and no-choice tests. The development of wild B. tabaci population on tomato plants protected by the same nets was followed in two field trials implemented in Njoro, Kenya. Results obtained with the no-choice tests showed a significant reduction of movement on the treated net with 40-mesh (19%) compared with nontreated netting (35 and 46% with 80- and 40-mesh, respectively). The mortality of B. tabaci was significantly higher (two-fold) in the test tube containing only the treated netting compared with the nontreated one. The repellent effect of the treated netting was also demonstrated against E. formosa, but it did not have this toxic effect. Unlike for B. tabaci, the treated and nontreated nets appeared to have a similar repellent effect on E. formosa in the choice test, which suggests a learning behavior of the parasitoid. In both field tests, B. tabaci population was significantly lower on tomato protected by the treated net compared with the same nontreated net. However there was no significant difference in B. tabaci

  10. Combined analysis of pharmacokinetic and efficacy data of preclinical studies with statins markedly improves translation of drug efficacy to human trialss

    NARCIS (Netherlands)

    Steeg, E. van de; Kleemann, R.; Jansen, H.T.; Duyvenvoorde, W. van; Offerman, E.H.; Wortelboer, H.M.; DeGroot, J.

    2013-01-01

    Correct prediction of human pharmacokinetics (PK) and the safety and efficacy of novel compounds based on preclinical data, is essential but often fails. In the current study, we aimed to improve the predictive value of ApoE*3Leiden (E3L) trans-genic mice regarding the cholesterol-lowering efficacy

  11. A QSAR Study of the Repellency of some Terpenoids to the Bedbug Cimex lectularius L.%萜类臭虫(Cimex lectularius L.)驱避化合物的定量构效关系研究

    Institute of Scientific and Technical Information of China (English)

    宋杰; 王宗德; 韩招久; 陈金珠; 姜志宽; 郑卫青; 商士斌

    2012-01-01

    测定了一系列六元环萜类化合物对臭虫(Cimex lectularius L.)的驱避活性,利用Codessa Pro程序计算了这些化合物的结构描述符,再利用Codessa Pro程序中的最优线性回归方法计算了驱避活性与这些化合物结构描述符之间的定量构效关系.所得到的最优定量构效关系计算模型的R2为0.924,模型所包含的4个参数分别是:FNSA3 fractional PNSA、Min n-n repulsion for bond H-C、YZ Shadow/YZ rectangle、Max electrophilic reactivity index for atom C.通过对模型的分析讨论了臭虫化学感受器与驱避剂之间可能存在的相互作用.%The quantitative structure-activity relationship (QSAR) between the repellency against bedbug,Cimex lectularius L.(Hemiptera:Cimicidae) and the molecular structural descriptors of a series of terpenoid compounds with six-member-ring was correlated by best multilinear regression (BMLR) method.The descriptors and the multilinear regression were all calculated by Codessa Pro.The optimum multilinear model with R2 value of 0.924 and 4 descriptors,i.e.the fractional atomic charge weighted partial megative surface area (FNSA3) fractional the atomic charge weighted partial negative charge molecular surface area (PNSA),Min n-n repulsion for bond H-C,YZ Shadow/YZ rectangle and Max electrophilic reactivity index for atom C was validated and presented.The probable interaction between the chemoreceptor of bedbug and the repellent was also discussed according to the optimum model and its descriptors.

  12. Development of novel repellents using structure-activity modeling of compounds in the USDA archival database

    Science.gov (United States)

    The United States Department of Agriculture (USDA) has developed repellents and insecticides for the U.S. military since 1942. Repellency and toxicity data for over 30,000 compounds are contained within the USDA archive. Repellency data from subsets of similarly structured compounds were used to dev...

  13. Fire-induced water repellency: An erosional factor in wildland environments

    Science.gov (United States)

    Leonard F. DeBano

    2000-01-01

    Watershed managers and scientists throughout the world have been aware of fire-induced water-repellent soils for over three decades. Water repellency affects many hydrologic processes, including infiltration, overland flow, and surface erosion (rill and sheet erosion). This paper describes; the formation of fire-induced water-repellent soils, the effect of soil water...

  14. Natural and fire-induced soil water repellency in a Portugese Shrubland

    NARCIS (Netherlands)

    Stoof, C.R.; Moore, D.; Ritsema, C.J.; Dekker, L.W.

    2011-01-01

    Post-fire land degradation is often attributed to fire-induced soil water repellency, despite the fact that soil water repellency is a natural phenomenon in many soils and is therefore not necessarily caused by fire. To improve our understanding of the role of soil water repellency in causing fire-i

  15. Development of Hydrophobic Coatings for Water-Repellent Surfaces Using Hybrid Methodology

    Science.gov (United States)

    2014-04-01

    windows, optical components, protective eyewear, and clothing, this type of surface is desired for the material to be soil repellent and water ...Development of Hydrophobic Coatings for Water - Repellent Surfaces Using Hybrid Methodology by Amanda S. Weerasooriya, Jacqueline Yim, Andres A...Proving Ground, MD 21005-5069 ARL-TR-6898 April 2014 Development of Hydrophobic Coatings for Water - Repellent Surfaces Using Hybrid

  16. Natural and fire-induced soil water repellency in a Portugese Shrubland

    NARCIS (Netherlands)

    Stoof, C.R.; Moore, D.; Ritsema, C.J.; Dekker, L.W.

    2011-01-01

    Post-fire land degradation is often attributed to fire-induced soil water repellency, despite the fact that soil water repellency is a natural phenomenon in many soils and is therefore not necessarily caused by fire. To improve our understanding of the role of soil water repellency in causing

  17. Spatial probability of soil water repellency in an abandoned agricultural field in Lithuania

    Science.gov (United States)

    Pereira, Paulo; Misiūnė, Ieva

    2015-04-01

    Water repellency is a natural soil property with implications on infiltration, erosion and plant growth. It depends on soil texture, type and amount of organic matter, fungi, microorganisms, and vegetation cover (Doerr et al., 2000). Human activities as agriculture can have implications on soil water repellency (SWR) due tillage and addition of organic compounds and fertilizers (Blanco-Canqui and Lal, 2009; Gonzalez-Penaloza et al., 2012). It is also assumed that SWR has a high small-scale variability (Doerr et al., 2000). The aim of this work is to study the spatial probability of SWR in an abandoned field testing several geostatistical methods, Organic Kriging (OK), Simple Kriging (SK), Indicator Kriging (IK), Probability Kriging (PK) and Disjunctive Kriging (DK). The study area it is located near Vilnius urban area at (54 49' N, 25 22', 104 masl) in Lithuania (Pereira and Oliva, 2013). It was designed a experimental plot with 21 m2 (07x03 m). Inside this area it was measured SWR was measured every 50 cm using the water drop penetration time (WDPT) (Wessel, 1998). A total of 105 points were measured. The probability of SWR was classified in 0 (No probability) to 1 (High probability). The methods accuracy was assessed with the cross validation method. The best interpolation method was the one with the lowest Root Mean Square Error (RMSE). The results showed that the most accurate probability method was SK (RMSE=0.436), followed by DK (RMSE=0.437), IK (RMSE=0.448), PK (RMSE=0.452) and OK (RMSE=0.537). Significant differences were identified among probability tests (Kruskal-Wallis test =199.7597 p<0.001). On average the probability of SWR was high with the OK (0.58±0.08) followed by PK (0.49±0.18), SK (0.32±0.16), DK (0.32±0.15) and IK (0.31±0.16). The most accurate probability methods predicted a lower probability of SWR in the studied plot. The spatial distribution of SWR was different according to the tested technique. Simple Kriging, DK, IK and PK methods

  18. A study of self-efficacy in job-related context

    Directory of Open Access Journals (Sweden)

    Špela Frlec

    2005-04-01

    Full Text Available The article stems from an attempt to transfer the Bandura's social cognitive theory into organisational praxis. Beliefs of self-efficacy, which is defined as people's judgments of their capabilities to organize and execute courses of action required to attain designated types of performances, are constructed from 4 principal sources of information: enactive mastery experiences; vicarious experiences that alter efficacy beliefs through transmission of competencies and comparison with the attainment of others; verbal persuasion and allied types of social influences that one possesses certain capabilities; and physiological and affective states from which people partly judge their capableness, strength, and vulnerability to dysfunction. The study of self-efficacy in job-related context involved 295 employees from 3companies belonging to the same business group. Self-efficacy was assed using Schwarzer's scale, while rating scales were used for assessing the 4 principal sources of influence upon it. First, differences between companies regarding demographic characteristics of the employees, job characteristics and self-efficacy were analyzed. Dependence of employee's self-efficacy on his/her age, gender, education, work experience, employment status, job type and the four principal influence sources was tested using a regression model. Finally, we identified typical employee profiles with respect to the studied factors. We hope that our study will help human-resources specialists design appropriate interventions for developing a resilient sense of self-efficacy in the employees.

  19. Acute and sub acute toxicity and efficacy studies of Hippophae rhamnoides based herbal antioxidant supplement

    Directory of Open Access Journals (Sweden)

    Rashid Ali

    2012-01-01

    Conclusion: The data obtained indicate no toxicity of this antioxidant supplement up to the highest dose studied. Efficacy in terms of increased bioavailability of vitamin A and C in human volunteers indicates the clinical usefulness of the supplement.

  20. A STUDY OF EFFICACY AND SAFETY OF TACROLIMUS COMPARED WITH CYCLOSPORIN A MICROEMULSION IN RENAL TRANSPLANTATION

    National Research Council Canada - National Science Library

    Jayakumar Edathedathe Krishnan; Noushad Thekke Puthiyottil; Sreelatha Melemadathil

    2016-01-01

    BACKGROUND The aim of this retrospective study was to compare therapeutic efficacy and safety profile of Cyclosporin and Tacrolimus in posttransplant patients with respect to graft function and metabolic disorders...

  1. Boron nitride nanosheet coatings with controllable water repellency.

    Science.gov (United States)

    Pakdel, Amir; Zhi, Chunyi; Bando, Yoshio; Nakayama, Tomonobu; Golberg, Dmitri

    2011-08-23

    The growth, structure, and properties of two-dimensional boron nitride (BN) nanostructures synthesized by a thermal chemical vapor deposition method have been systematically investigated. Most of the BN nanosheets (BNNSs) were less than 5 nm in thickness, and their purity was confirmed by X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and Raman spectroscopy. The effects of the process variables on the morphology and roughness of the coatings were studied using atomic force microscopy and scanning electron microscopy. A smooth BN coating was obtained at 900 °C, while compact BNNS coatings composed of partially vertically aligned nanosheets could be achieved at 1000 °C and higher temperatures. These nanosheets were mostly separated and exhibited high surface area especially at higher synthesis temperatures. The nonwetting properties of the BNNS coatings were independent of the water pH and were examined by contact angle goniometry. The present results enable a convenient growth of pure BNNS coatings with controllable levels of water repellency, ranging from partial hydrophilicity to superhydrophobicity with contact angles exceeding 150°. © 2011 American Chemical Society

  2. Repellence and attraction of Apis mellifera foragers by nectar alkaloids

    Directory of Open Access Journals (Sweden)

    Hroncová Z.

    2016-03-01

    Full Text Available Plant secondary metabolites present naturally in nectar, such as alkaloids, may change the behavioural responses of floral visitors and affect pollination. Some studies have shown that nectar containing low concentrations of these secondary metabolites is preferred by honey bee foragers over pure nectar. However, it remains unclear whether this is caused by dependence or addictive behaviour, a simple taste preference, or by other conditions such as self-medication. In our choice experiment, free-flying bees were presented with artificial flowers holding 20% sucrose containing 0.5−50 μg ml−1 of one of the naturally occurring nectar alkaloids - caffeine, nicotine, senecionine, and gelsemine. Nectar uptake was determined by weighing each flower and comparing the weight to that of the control flower. Our experimental design minimized memorizing and marking; despite this, caffeine was significantly preferred at concentrations 0.5−2 μg ml−1 over control nectar; this preference was not observed for other alkaloids. All of the compounds tested were repellent at concentrations above 5 μg ml−1. We confirmed previous reports that bees exhibit a preference for caffeine, and hypothesize that this is not due only to addictive behaviour but is at least partially mediated by taste preference. We observed no significant preference for nicotine or any other alkaloid.

  3. Laboratory evaluation of Indian medicinal plants as repellents against malaria, dengue, and filariasis vector mosquitoes.

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2015-02-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticides, in the present study, the repellent activity of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Erythrina indica and root of Asparagus racemosus were assayed for their repellency against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The crude extract was applied on a membrane used for membrane feeding of unfed mosquitoes in a 1-ft cage. About 50 unfed 3-4-day-old laboratory-reared pathogen-free strains of A. stephensi, A. aegypti, and C. quinquefasciatus were introduced in a 1-ft cage fitted with a membrane with blood for feeding with temperature maintained at 37 °C through circulating water bath maintained at 40-45 °C. Three concentrations (1.0, 2.0, and 5.0 mg/cm(2)) of the crude extracts were evaluated. Repellents in E. indica afforded longer protection time against A. stephensi, A. aegypti, and C. quinquefasciatus than those in A. racemosus at 5.0 mg/cm(2) concentration, and the mean complete protection time ranged from 120 to 210 min with the different extracts tested. In this observation, these two plant crude extracts gave protection against mosquito bites; also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf extract of E. indica and root extract of A. racemosus have the potential to

  4. The Exploration of Elementary School Teachers' Internet Self-Efficacy and Information Commitments: A Study in Taiwan

    Science.gov (United States)

    Wu, Ying-Tien; Wang, Li-Jen

    2015-01-01

    This study aimed to explore teachers' Internet self-efficacy and information commitments. More importantly, this study also attempted to identify possible factors that affect the teachers' Internet self-efficacy. The participants were 301 elementary school teachers. In this study, the Internet Self-efficacy Survey (ISS) and the Information…

  5. Self-efficacy is mainly genetic, not learned: a multiple-rater twin study on the causal structure of general self-efficacy in young people.

    Science.gov (United States)

    Waaktaar, Trine; Torgersen, Svenn

    2013-06-01

    Social learning theory postulates that self-efficacy is learned through the person's interaction with his/her physical and social environment. In this genetically informative, population-based, multi-informant study of 1,394 adolescent twin pairs, self-efficacy was modeled as one latent psychometric self-efficacy factor with genetic and environmental effects common to all informants, as well as for effects specific for each informant. The results showed that 75% of variation in self-efficacy was due to genetic factors. Non-shared environmental causes explained the remaining 25% of the variance in the latent factor, with no effect of common environment. Some informant-specific effects were also found. The present study challenges the theoretical assumption of learning as the dominant etiological factor behind self-efficacy in young people.

  6. Comparative assessment of antimicrobial efficacy of different hand sanitizers: An in vitro study

    OpenAIRE

    Jain, Vardhaman Mulchand; Karibasappa, Gundabaktha Nagappa; Dodamani, Arun Suresh; Prashanth, Vishwakarma K.; Mali, Gaurao Vasant

    2016-01-01

    Background: To evaluate the antimicrobial efficacy of four different hand sanitizers against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis as well as to assess and compare the antimicrobial effectiveness among four different hand sanitizers. Materials and Methods: The present study is an in vitro study to evaluate antimicrobial efficacy of Dettol, Lifebuoy, PureHands, and Sterillium hand sanitizers against clinical isola...

  7. Comparative assessment of antimicrobial efficacy of different hand sanitizers: An in vitro study

    OpenAIRE

    Vardhaman Mulchand Jain; Gundabaktha Nagappa Karibasappa; Arun Suresh Dodamani; Prashanth, Vishwakarma K.; Gaurao Vasant Mali

    2016-01-01

    Background: To evaluate the antimicrobial efficacy of four different hand sanitizers against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis as well as to assess and compare the antimicrobial effectiveness among four different hand sanitizers. Materials and Methods: The present study is an in vitro study to evaluate antimicrobial efficacy of Dettol, Lifebuoy, PureHands, and Sterillium hand sanitizers against clinical i...

  8. A multilevel study on the relationships between work characteristics, self-efficacy, collective efficacy, and organizational citizenship behavior: the case of Taiwanese police duty-executing organizations.

    Science.gov (United States)

    Chen, Chun-Hsi Vivian; Kao, Rui-Hsin

    2011-01-01

    Public security, traffic management, and service for the people are the 3 major functions of policing in Taiwan. This definition encompasses not only the traditional job characteristics, but also the level of contextual characteristics and social characteristics because of police work's characteristics and its frequent interaction with the public. Thus, the present study conducted a multilevel model analysis by taking self-efficacy and collective efficacy as the mediating variables. The purpose was to investigate the influences of motivational work characteristics (knowledge-oriented) and social work characteristics (socially and contextually oriented) of work-design model on the police officers' organizational citizenship behavior (OCB), by using first-line police officers in Taiwan as the research objects. The study showed not only that knowledge characteristics will influence the self-efficacy of a police officer and that self-efficacy can in turn influence individual police officers' OCB, but also the contextual effect of social characteristics, contextual characteristics, and collective efficacy on self-efficacy and individuals' OCB. Additionally, there was a crosslevel moderating effect from contextual characteristics on the relationship between knowledge characteristics and self-efficacy and the relationship between self-efficacy and the individuals' OCB. The authors conclude the article with research implications.

  9. Larvicidal and repellent properties of Adansonia digitata against medically important human malarial vector mosquito Anopheles stephensi (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    K. Krishnappa , K. Elumalai , S. Dhanasekaran & J. Gokulakrishnan

    2012-06-01

    Full Text Available Background & objectives: Development of plant-based alternative compounds for mosquito control has gainedimportance now-a-days, in view of increasing resistance in mosquito vectors to existing insecticides. The larvicidaland repellent activities of benzene, chloroform, hexane and methanol leaf extracts of Indian medicinal plant,Adansonia digitata were investigated against malarial vector, Anopheles stephensi.Methods: In all, 25 III instar larvae of An. stephensi were exposed to various concentrations (30–180 mg/l in thelaboratory by using the standard protocol described by WHO (2005. The larvae were exposed for 24 h andmortalities were subjected to log-probit analysis. Repellent activity of crude leaf extract at the dosages of 2, 4and 6 mg/cm2 was evaluated in a net cage (45 × 30 × 45 cm containing 100 blood starved female mosquitoes ofAn. stephensi using the protocol of WHO (1996.Results: Preliminary phytochemical analysis of A. digitata showed the presence of triterpenoids and saponins.The LC50 and LC90 values of hexane, benzene, chloroform, and methanol extracts of A. digitata against An.stephensi larvae in 24 h were 111.32, 97.13, 88.55, 78.18 and 178.63, 176.19, 168.14, 155.42 mg/l, respectively.The repellent activity of methanol extract was found to be most effective and at higher concentration of 6mg/cm2 benzene, chloroform hexane and methanol extracts provided 100% protection up to 150, 180, 120 and210 min against An. stephensi, respectively.Conclusion: The preliminary study indicated that A. digitata showed larvicidal and repellent activities againstAn. stephensi and could be used for controlling mosquitoes. Further studies are indicated to purify the activecompounds from these plants for developing larvicide and repellents.

  10. Comparative mosquito repellency of essential oils against Aedes aegypti (Linn.), Anopheles dirus (Peyton and Harrison) and Culex quinquefasciatus (Say)

    Institute of Scientific and Technical Information of China (English)

    Siriporn Phasomkusolsil; Mayura Soonwera

    2011-01-01

    Objective: To assess the repellency to female Aedes aegypti (Ae. aegypti), Anopheles dirus (An. dirus) and Culex quinquefasciatus (Cx. quinquefasciatus) of seven essential oils using two treatment methods. Methods: Topical applications of three dose concentrations (0.02, 0.10 and 0.21 mg/cm2) were made on the forearms of volunteers. Dose-response study and protection time study were employed in the experiment. Results: In the dose-response test, Cymbopogon citratus (C. citratus), Cymbopogon nardus (C. nardus), Syzygium aromaticum (S. aromaticum) and Ocimum basilicum (O. basilicum) exhibited a high repellency against Ae. aegypti with ED50 at < 0.045 mg/cm2, whereas C. citratus, C. nardus and S. aromaticum showed repellency against An. dirus with ED50 at <0.068 mg/cm2. Furthermore, the essential oils of C. citratus, C. nardus, S. aromaticum, O.basilicum and Cananga odorata gave strong effective dose (ED 50) values at <0.003 mg/cm2 when tested against Cx. quinquefasciatus. For testing by arm in cage method, at 0.21 mg/cm2, protection time of C. citratus gave the longest lasting period against three mosquito species, 72 min for Ae. aegypti, 132 min for An. dirus and 84 min for Cx. quinquefasciatus. In addition, the two essential oils exhibited moderate repellency against Ae. aegypti, An. dirus and Cx. quinquefasciatus, at 60, 90 and 78 min with C. nardus, and 54, 96 and 72 min with S. aromaticum, respectively. Conclusions: The percentage repellency increased when the concentration of essential oils increased. In contrast, biting rates decreased when the concentration of essential oils increased.C. citratus exhibited high efficiency for the protection time and the percentage of biting deterrent against all of 3 mosquito species.

  11. Joint modeling of clinical efficacy and safety with an application to diabetes studies.

    Science.gov (United States)

    Zhao, Yang; Shen, Wei; Fu, Haoda

    2013-01-01

    The purpose of drug development is to evaluate a drug's efficacy and safety profile. For a personalized medicine, it is important for patients and health care providers to understand the efficacy and safety trade-off when selecting a dose for a patient. In this article, we propose three different methods for jointly modeling the clinical safety and efficacy endpoints. These three methods model the correlation relationship in three different ways: modeling the joint distribution by a copula method, modeling conditional distributions, and modeling their correlations through individual means by a hierarchical model. We compare these three methods through simulations and apply these methods to a data set from a diabetes study.

  12. An in vitro bioassay for the quantitative evaluation of mosquito repellents against Stegomyia aegypti (=Aedes aegypti) mosquitoes using a novel cocktail meal.

    Science.gov (United States)

    Huang, T-H; Tien, N-Y; Luo, Y-P

    2015-09-01

    To assess the efficacy of new insect repellents, an efficient and safe in vitro bioassay system using a multiple-membrane blood-feeding device and a cocktail meal was developed. The multiple-membrane blood-feeding device facilitates the identification of new insect repellents by the high-throughput screening of candidate chemicals. A cocktail meal was developed as a replacement for blood for feeding females of Stegomyia aegypti (=Aedes aegypti) (L.) (Diptera: Culicidae). The cocktail meal consisted of a mixture of salt, albumin and dextrose, to which adenosine triphosphate was added to induce engorging. Feeding rates of St. aegypti on the cocktail meal and pig blood, respectively, did not differ significantly, but were significantly higher than the feeding rate on citrate phosphate dextrose-adenine 1 (CPDA-1) solutions, which had been used to replace bloodmeals in previous repellent assays. Dose-dependent biting inhibition rates were analysed using probit analysis. The RD(50) (the dose producing 50% repellence of mosquito feeding) values of DEET, citronella, carvacrol, geraniol, eugenol and thymol were 1.62, 14.40, 22.51, 23.29, 23.83 and 68.05 µg/cm(2), respectively.

  13. Effects of hydrophilic macropore fillings and coatings on the infiltration into water repellent porous media

    Science.gov (United States)

    Suetsugu, A.; Mori, Y.

    2012-12-01

    Macropores generate rapid flow paths in the surface soils by their high permeability under saturated/near-saturated moisture conditions. In natural soils, some macropores are filled/coated with various materials including decayed plant roots (Meek et al., 1989), exudates from plants/soil organisms (Jegou et al., 2001), iron oxides or other precipitates from preferentially-introduced solutes/colloids to the macropores (Rasmussen et al., 2001), or the surrounding soils with reduced bulk density (Ela et al., 1992). When we expect infiltration into water repellent soils through macropores or hydrophilic patches created from the macropore cementation processes, hydrophilicity of the macropore fillings/coatings should be understood. In the present study, we conducted an infiltration experiment with water repellent porous media and some macropore fillings/coatings, in order to clarify the roles of hydrophilic macropore fillings/coatings in infiltration. Ponding depth and flow distribution were monitored with a micro-focus X-ray computational tomography apparatus (SMX-90CT, Shimadzu Corp., Kyoto, Japan) at 90 kV and 110 μA. Dilute CsCl(aq) (density: 1.04 Mg m-3) was used as the contrast media to avoid density-driven alteration of the flows. Water repellency of the samples was evaluated by the water drop penetration time (WDPT, Van't Woudt, 1959). A glass beads (mean diameter: 0.46 mm, BZ-04, ASONE Corp., Osaka, Japan) was used as water repellent porous media. The glass beads sample was packed in 50-mL polypropylene centrifugation tubes at 1.55 Mg m-3 bulk density. A 2-mm hole was made at the bottom of each centrifugation tube for ventilation. The hole was covered with mesh cloth. Macroporous structure was made at the center of each tube from the surface. Each macroporous structure had 4-mm diameter and 30-mm length. Six types of macropores were prepared including 1) no macropore, 2) empty macropore, 3) an aluminum (Al) pipe (4-mm inner diameter, 5-mm outer diameter), 4) a

  14. Isolated Pelvic Hyperthermochemotherapeutic Perfusion -An Experimental Study on Isolating Efficacy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Hyperthermochemotherapeutic perfusion model through isolated pelvic vessels was developed to evaluate the leakage of hyperthermia and drugs (such as adriamycin) from the isolated pelvic circulation to systemic circulation and its associated side/toxic effects. The isolated pelvic circulation was perfused through a femoral artery catheter with hyperthermic (48 ℃ to 55 ℃) adriamycin solution (50 μg/ml) for 30 min. The efflux was drained through a femoral vein catheter. And the pelvic temperature was kept at the level of 43±0.5 ℃. The temperature of pelvic circulation was kept at 4 ℃ to 5 ℃ greater than the systemic/core temperature. The adriamycin concentration of pelvic efflux was 12 to 46 folds of that of systemic serum. The difference between them was very significant (P<0.001). As the perfusion pressure was increased, which kept lower than the mean systemic artery pressure, the leakage of the adriamycin from the isolated pelvic circulation to systemic circulation was increased, but there was no significant difference between them (P>0.05). During isolated perfusion, the systemic blood dynamics remained stable and there were no organic injuries on the important organs. It was suggested that the isolating efficacy of the modality of isolated pelvic hyperthermochemotherapeutic perfusion through vessels was rather high. The hyperthermia and drugs could be effectively limited in the isolated pelvic region with minor side effects on the systemic circulation and important organs.

  15. An Exploratory Study into the Efficacy of Learning Objects

    Directory of Open Access Journals (Sweden)

    Nicholas W. Farha

    2009-07-01

    Full Text Available Learning objects have quickly become a widely accepted approach to instructional technology, particularly in on-line and computer-based learning environments. While there is a substantial body of literature concerning learning objects, very little of it verifies their efficacy. This research investigated the effectiveness of learning objects by comparing learning outcomes using a learning object with outcomes using a traditional textbook-based method of instruction. Participants were 327 undergraduate college students at a traditional public four-year coed institution, a private four-year women’s college, a private four-year engineering institution, and a public two-year community college. Through a series of independent samples t-tests and Analyses of Variance, results revealed mean scores for the learning object group that were nearly three times higher than the mean scores for the textbook-taught group. Gaming experience, age, gender, and learner preference were evaluated for their potential influence on the results; no statistically significant differences were found, implying that the learning object itself was central to the outcomes achieved. The future of learning objects is bright, and more empirical research is called for in the area of learning object effectiveness.

  16. Induction and Efficacy: A Case Study of New Zealand Newly Qualified Secondary Science Teachers

    Science.gov (United States)

    Haigh, Mavis A.; Anthony, Glenda J.

    2012-10-01

    This paper reports on 20 newly qualified secondary science teachers (NQSSTs) participating in a New Zealand study on teachers' early professional learning. The focus of our study is how these new teachers were nurtured to become competent science teachers, confident of their ability to positively influence student learning. Based on responses to a graduating questionnaire and three interviews across their first 18 months of teaching, we look at the effect of induction and contextual factors on the teachers' efficacy. While the NQSSTs overall reported relatively constant ratings of self-efficacy, they demonstrated different patterns of declared efficacy across this 18-month period. Findings regarding the influence of induction practices and contextual factors on the efficacy of these teachers are mixed.

  17. Assessment of methods used to determine the safety of the topical insect repellent N,N-diethyl-m-toluamide (DEET).

    Science.gov (United States)

    Chen-Hussey, Vanessa; Behrens, Ron; Logan, James G

    2014-06-03

    N,N-diethyl-m-toluamide (DEET) has been registered for commercial use as an insect repellent for over five decades, and is used widely across the world. Concerns over the safety of DEET first emerged during the 1980s after reports of encephalopathy following DEET exposure, particularly in children. However, the role of DEET in either the illness or deaths was and remains purely speculative. In response to these cases a number of reviews and investigations of DEET safety were carried out. Here we examine the methods used and information available to determine the safety of DEET in humans. Animal testing, observational studies and intervention trials have found no evidence of severe adverse events associated with recommended DEET use. Minor adverse effects noted in animal trials were associated with very large doses and were not replicated between different test species. The safety surveillance from extensive humans use reveals no association with severe adverse events. This review compares the toxicity assessment using three different models to define the risk assessment and safety threshold for DEET use in humans and discusses the clinical consequences of the thresholds derived from the models.The theoretical risks associated with wearing an insect repellent should be weighed against the reduction or prevention of the risk of fatal or debilitating diseases including malaria, dengue, yellow fever and filariasis. With over 48 million European residents travelling to regions where vector borne diseases are a threat in 2009, restricting the concentration of DEET containing repellents to 15% or less, as modelled in the 2010 EU directive, is likely to result in extensive sub-therapeutic activity where repellents are infrequently applied. Future European travellers, as a consequence of inadequate personal protection, could potentially be at increased risk of vector borne diseases. Risk assessments of repellents should take these factors into account when setting safe

  18. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoyu [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); He, Junhui, E-mail: jhhe@mail.ipc.ac.cn [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Liu, Weiyi [Institute of Optoelectronics, Nankai University, Tianjin 300071 (China)

    2013-07-15

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO{sub 2} nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system.

  19. The relationship between prosocial and antisocial behaviors in sport, general self-efficacy and academic self-efficacy: Study in department of physical education and sport teacher education

    OpenAIRE

    Yıldız, Mevlüt; ŞENEL, Ender; Şahan, Hasan

    2015-01-01

    The aim of this study was to examine the relationship between prosocial and antisocial behaviors in sport, general self-efficacy and academic self-efficacy beliefs of students studying in physical education and sport teacher education department. 118 students in department of physical education and sport teacher education at Mugla Sitki Kocman University voluntarily participated in the study.  31 of the participants were national athletes while 87 of them were non-national athletes. 50 of the...

  20. Efficacy of deltamethrin, diazinon, and ivermectin on Boophilus annulatus ticks (in vitro and in vivo study).

    Science.gov (United States)

    El-Bahy, Nasr M; Bazh, Eman K; Shaheen, Hazem M

    2015-01-01

    Tick infection is considered a cause of major concern as it is a vector for some disease transmission. The use of chemicals to control tick infection is increasing in farm systems. The efficacy of three chemicals was studied on the tick Boophilus annulatus. In vitro and in vivo studies were done. The active ticks were collected from naturally infected cattle for in vitro study. They were incubated with the three chemicals which are commercially used. An in vitro study recorded that the highest effect of the three chemicals was 100% at 3 h postexposure (p.e.) time for deltamethrin and 6 h for diazinon and ivermectin on the adult ticks. Egg batches were less affected. In vivo results showed more plain efficacy. The efficacy of deltamethrin was increased gradually until complete cessation of ticks showed within 3rd day posttreatment (d.p.t.), 100% efficacy. But the tick population begins to reappear gradually within 7 d.p.t., while diazinon showed 100% efficacy at 7 d.p.t. and the ticks reappear again within 14 d.p.t. The most preferred results were obtained with ivermectin which showed 100% efficacy at 7 d.p.t., and the cattle was still free from infection until 21 d.p.t. only. Ticks begin to reappear within 28 d.p.t. in slight few numbers. This concluded that the powerful and safe chemical which is commercially used was ivermectin. Even so, it is used also as an anthelmintic drug.

  1. Teaching efficacy of nurses in clinical practice education: A cross-sectional study.

    Science.gov (United States)

    Kim, Eun-Kyeung; Shin, Sujin

    2017-07-01

    Clinical nurses play a vital role in clinical practice education; thus, it is necessary to help clinical nurses have teaching efficacy through the development and application of systematic education programs. To identify nurses' teaching efficacy for clinical education and analyze the influencing factors of teaching efficacy. The study used a cross-sectional design. We used a convenience sample of 263 nurses from two hospitals. Teaching efficacy, general characteristics, and perception of clinical practice education were collected via self-reported questionnaires. Teaching efficacy was measured using Hwang's (2006) questionnaire, while perception of clinical practice education was measured using the Clinical Nurse Teacher Survey developed by Nishioka et al. (2014). Participants completed the questionnaire directly. The collected data were then analyzed using descriptive statistics, t-tests, ANOVAs, and multiple regression analysis with PASW Statistics 18.0. The mean total score of teaching efficacy was 72.5 (range 21-105). The leadership for students subscale had the highest score (3.56±0.59). The factors influencing teaching efficacy were length of clinical career (β=0.26, pteaching efficacy in nurses. Based on these results, nursing educators might need to develop greater confidence in their knowledge and enhance control of their teaching strategies. Nursing schools and hospitals might need to provide greater support and educational opportunities to nurse clinical practice instructors. Furthermore, constructing a system of cooperation between these colleges and educational hospitals, developing programs to enhance teaching efficacy, and identifying the clinical instructor's role are all necessary to promote clinical practice education. Copyright © 2017. Published by Elsevier Ltd.

  2. Post-fire interactions between soil water repellency, soil fertility and plant growth in soil collected from a burned piñon-juniper woodland

    Science.gov (United States)

    Fernelius, Kaitlynn J.; Madsen, Matthew D.; Hopkins, Bryan G.; Bansal, Sheel; Anderson, Val J.; Eggett, Dennis L.; Roundy, Bruce A.

    2017-01-01

    Woody plant encroachment can increase nutrient resources in the plant-mound zone. After a fire, this zone is often found to be water repellent. This study aimed to understand the effects of post-fire water repellency on soil water and inorganic nitrogen and their effects on plant growth of the introduced annual Bromus tectorum and native bunchgrass Pseudoroegneria spicata. Plots centered on burned Juniperus osteosperma trees were either left untreated or treated with surfactant to ameliorate water repellency. After two years, we excavated soil from the untreated and treated plots and placed it in zerotension lysimeter pots. In the greenhouse, half of the pots received an additional surfactant treatment. Pots were seeded separately with B. tectorum or P. spicata. Untreated soils had high runoff, decreased soilwater content, and elevated NO3eN in comparison to surfactant treated soils. The two plant species typically responded similar to the treatments. Above-ground biomass and microbial activity (estimated through soil CO2 gas emissions) was 16.8-fold and 9.5-fold higher in the surfactant-treated soils than repellent soils, respectably. This study demonstrates that water repellency can influence site recovery by decreasing soil water content, promoting inorganic N retention, and impairing plant growth and microbial activity.

  3. Larvicidal and repellent activity of the essential oil of Coriandrum sativum L. (Apiaceae) fruits against the filariasis vector Aedes albopictus Skuse (Diptera: Culicidae).

    Science.gov (United States)

    Benelli, Giovanni; Flamini, Guido; Fiore, Giulia; Cioni, Pier Luigi; Conti, Barbara

    2013-03-01

    The essential oils of many Apiaceae species have been already studied for their insecticidal and repellent properties against insect pests. In this research, the essential oil (EO) extracted from the fruits of Coriandrum sativum L. (Apiaceae) was evaluated for the first time for its larvicidal and repellent activities against the most invasive mosquito worldwide, Aedes albopictus Skuse (Diptera: Culicidae). The chemical composition of C. sativum EO was investigated by gas chromatography with electron impact mass spectrometry analysis. Coriander EO was mainly composed by monoterpene hydrocarbons and oxygenated monoterpenes, with linalool (83.6 %) as the major constituent. C. sativum EO exerted toxic activity against A. albopictus larvae: LC(50) was 421 ppm, while LC(90) was 531.7 ppm. Repellence trials highlighted that C. sativum EO was a good repellent against A. albopictus, also at lower dosages: RD(50) was 0.0001565 μL/cm(2) of skin, while RD(90) was 0.002004 μL/cm(2). At the highest dosage (0.2 μL/cm(2) of skin), the protection time achieved with C. sativum essential oil was higher than 60 min. This study adds knowledge about the chemical composition of C. sativum EO as well as to the larvicidal and repellent activity exerted by this EO against A. albopictus. On this basis, we believe that our findings could be useful for the development of new and safer products against the Asian tiger mosquito.

  4. Repelling periodic points of given periods of rational functions

    Institute of Scientific and Technical Information of China (English)

    CHANG Jianming; FANG Mingliang

    2006-01-01

    Let R(z) be a rational function of degree d ≥ 2. Then R(z) has at least one repelling periodic point of given period k ≥ 2, unless k = 4 and d=2, or k= 3 and d ≤ 3, or k=2 and d≤8. Examples show that all exceptional cases occur.

  5. Visible NearInfrared Spectroscopy Predicts Water Repellency in Soil

    DEFF Research Database (Denmark)

    Hermansen, Cecilie; Møldrup, Per; Clothier, Brent;

    Soil water repellency (SWR) is a property which has consequences for agricultural water management. The SWR is caused by hydrophobic organic coatings on mineral particles and the severity is highly depending on the organic matter quantity and quality and on the moisture status of the soil...

  6. An autopsy case of fatal repellent air freshener poisoning.

    Science.gov (United States)

    Hitosugi, Masahito; Tsukada, Chie; Yamauchi, Shinobu; Matsushima, Kazumi; Furukawa, Satoshi; Morita, Satomu; Nagai, Toshiaki

    2015-09-01

    We describe a first fatal case of repellent air freshener ingestion. A 79-year-old Japanese man with Alzheimer-type senile dementia orally ingested repellent air freshener containing three surfactants: polyoxyethylene 9-lauryl ether, polyoxyethylene (40) hydrogenated castor oil, and lauric acid amidopropyl amine oxide (weight ratio of 1.3%). About 1h after the collapse, he was in cardiopulmonary arrest and subsequently died 10h after his arrival. The forensic autopsy performed 5.5h after death revealed the 380ml of stomach contents with a strong mint perfume identical to that of the repellent air freshener and the findings of acute death. Toxicologically, 9.1μg/ml and 558.2μg/ml of polyoxyethylene 9-lauryl ether were detected from the serum and stomach contents taken at autopsy. Generally, ingestion of anionic or non-ionic surfactants have been considered as safe. However, because the patient suffered from cardiac insufficiency with a low dose of repellent air freshener ingestion, medical staff members must evaluate the elderly patient for cardiac and circulatory problems regardless of the ingested dose. Not only medical and nursing staff members, but also families who are obliged to care for elderly persons must be vigilant to prevent accidental ingestion of toxic substances generally used in the household.

  7. Insect Repellents: Modulators of mosquito odorant receptor activity

    Science.gov (United States)

    Mosquitoes vector numerous pathogens that cause diseases including malaria, yellow fever, dengue fever and chikungunya. DEET, IR3535, Picaridin and 2-undecanone are insect repellents that are used to prevent interactions between humans and a broad array of disease vectors including mosquitoes. While...

  8. Water repellency of two forest soils after biochar addition

    Science.gov (United States)

    D. S. Page-Dumroese; P. R. Robichaud; R. E. Brown; J. M. Tirocke

    2015-01-01

    Practical application of black carbon (biochar) to improve forest soil may be limited because biochar is hydrophobic. In a laboratory, we tested the water repellency of biochar application (mixed or surface applied) to two forest soils of varying texture (a granitic coarse-textured Inceptisol and an ash cap fine-textured Andisol) at four different application rates (0...

  9. Causes and consequences of fire-induced soil water repellency

    Science.gov (United States)

    Letey, J.

    2001-10-01

    A wettable surface layer overlying a water-repellent layer is commonly observed following a fire on a watershed. High surface temperatures burn off organic materials and create vapours that move downward in response to a temperature gradient and then condense on soil particles causing them to become water repellent. Water-repellent soils have a positive water entry pressure hp that must be exceeded or all the water will runoff. Water ponding depths ho that exceeds hp will cause infiltration, but the profile is not completely wetted. Infiltration rate and soil wetting increase as the value of ho/hp increases. The consequence is very high runoff, which also contributes to high erosion on fire-induced water-repellent soils during rain storms. Grass establishment is impaired by seeds being eroded and lack of soil water for seeds that do remain and germinate. Extrapolation of these general findings to catchment or watershed scales is difficult because of the very high temporal and spatial variabilities that occur in the field.

  10. Fire-induced water-repellent soils, an annotated bibliography

    Science.gov (United States)

    Kalendovsky, M.A.; Cannon, S.H.

    1997-01-01

    The development and nature of water-repellent, or hydrophobic, soils are important issues in evaluating hillslope response to fire. The following annotated bibliography was compiled to consolidate existing published research on the topic. Emphasis was placed on the types, causes, effects and measurement techniques of water repellency, particularly with respect to wildfires and prescribed burns. Each annotation includes a general summary of the respective publication, as well as highlights of interest to this focus. Although some references on the development of water repellency without fires, the chemistry of hydrophobic substances, and remediation of water-repellent conditions are included, coverage of these topics is not intended to be comprehensive. To develop this database, the GeoRef, Agricola, and Water Resources Abstracts databases were searched for appropriate references, and the bibliographies of each reference were then reviewed for additional entries. Additional references will be added to this bibliography as they become available. The annotated bibliography can be accessed on the Web at http://geohazards.cr.usgs.gov/html_files/landslides/ofr97-720/biblio.html. A database consisting of the references and keywords is available through a link at the above address. This database was compiled using EndNote2 plus software by Niles and Associates, and is necessary to search the database.

  11. A Green Route for Substrate-Independent Oil-Repellent Coatings

    Science.gov (United States)

    Xu, Li-Ping; Han, Da; Wu, Xiuwen; Zhang, Qingqing; Zhang, Xueji; Wang, Shutao

    2016-11-01

    Oil repellent surface have lots of practical applications in many fields. Current oil repellent coating may suffer from limited liquid repellency to oils or environmental risks. In this work, we report an eco-friendly ‘green’ processes for preparing oil-repellent surface using a renewable and environmentally benign bioresource alginate. The oil-repellent coating was prepared by a two-step surface coating technique and showed stable oil repellency to many kinds of oils. The fabrication process was very simple with no need for special equipment, and this approach can be successfully employed to various substrates with different compositions, sizes and shapes, or even substrate-independent oil-repellent materials. The as-prepared coating of calcium alginate may have a good future in packaging oil-containing products and foods.

  12. Laboratory evaluation of four commercial repellents against larval Leptotrombidium deliense (Acari: Trombiculidae).

    Science.gov (United States)

    Hanifah, Azima Laili; Ismail, Siti Hazar Awang; Ming, Ho Tze

    2010-09-01

    Four commercial repellents were evaluated in the laboratory against Leptotrombidium deliense chiggers. Both in vitro and in vivo methods were used to determine repellency of the compounds. The repellents were Kellis (containing citronella oil, jojoba oil and tea tree oil), Kaps (containing citronella oil), BioZ (containing citronella oil, geranium oil and lemon grass oil) and Off (containing DEET). The combination of three active ingredients: citronella oil, geranium oil, lemon grass oil gave the highest repellency (87%) followed by DEET (84%). In vitro repellencies ranged from 73% to 87%. There was no significant difference between the four products. All the repellents had 100% in vivo repellency compared to 41-57% for the controls.

  13. Efficacy of an imidacloprid/flumethrin collar against fleas and ticks on cats

    Directory of Open Access Journals (Sweden)

    Stanneck Dorothee

    2012-04-01

    Full Text Available Abstract Background The objectives of the studies listed here were to ascertain the therapeutic and sustained efficacy of 10% imidacloprid (w/w and 4.5% flumethrin (w/w incorporated in a slow-release matrix collar, against laboratory-infestations of fleas and ticks on cats. Efficacy was evaluated against the flea Ctenocephalides felis felis, and the ticks Ixodes ricinus, Amblyomma americanum and Rhipicephalus turanicus. The number of studies was so large that only a general overview can be presented in this abstract. Methods Preventive efficacy was evaluated by infesting groups of cats (n = 8-10 with C. felis felis and/or I. ricinus, A. americanum or R. turanicus at monthly intervals at least, for a period of up to 8 months. Efficacy against fleas was evaluated 24 to 48 h after treatment and 24 h after infestation, and against ticks at 6 h (repellent or 48 h (acaricidal after infestation. Efficacy against flea larvae was evaluated over a period of 8 months by incubating viable flea eggs on blanket samples after cat contact. In all cases efficacy was calculated by comparison with untreated negative control groups. Results Efficacy against fleas (24 h generally exceeded 95% until study termination. In vitro efficacy against flea larvae exceeded 92% until Day 90 and then declined to 67% at the conclusion of the study on Day 230. Sustained acaricidal (48 h efficacy over a period of eight months was consistently 100% against I. ricinus from Day 2 after treatment, 100% against A. americanum, except for 98.5% and 97.7% at two time-points, and between 94% and 100% against R. turanicus. From Day 2 until 8 months after treatment the repellent (6 h, efficacy was consistently 100% against I. ricinus, and between 54.8% and 85.4% against R. turanicus. Conclusion The rapid insecticidal and acaricidal properties of the medicated collars against newly- acquired infestations of fleas and ticks and their sustained high levels of preventive efficacy have been

  14. Toward making the invisible visible: Studying science teaching self-efficacy beliefs

    Science.gov (United States)

    Perkins, Catherine J.

    This dissertation consists of two articles to be submitted for publication. The first, a literature review, makes visible common influences on science teaching self-efficacy beliefs and also points to potentially invisible validation concerns regarding the instrument used. The second investigates the participants' invisible science teaching self-efficacy beliefs and, through the use of a more focused interview, makes those beliefs visible. Science teaching self-efficacy beliefs are science teachers' perceptions of their abilities to teach science effectively. The construct "teaching self-efficacy" originated in social cognitive theory (Bandura, 1977). The first article reviews the mixed results from teaching self-efficacy research in science contexts. The review focuses upon factors that facilitate or inhibit the development of self-efficacy beliefs among science teachers across stages of their careers. Although many studies of science teaching self-efficacy beliefs have utilized the Science Teaching Efficacy Belief Instrument - STEBI (Enochs & Riggs, 1990; Riggs & Enochs, 1990), this review also includes non-STEBI studies in order to represent diverse lines of research methodology. The review's findings indicate that antecedent factors such as science activities in and out of school, teacher preparation, science teaching experiences and supportive job contexts are significant influences on the development of science teaching self-efficacy beliefs. The review also indicates that the majority of these studies are short term and rely on a single STEBI administration with the collection of antecedent/demographic and/or interview data. The second article documents a study that responded to the above literature review findings. This study utilized multiple STEBI administrations during the preservice and beginning year of teaching for two science teachers. Rather than general questions, these participants were asked item specific, yet open-ended, questions to determine

  15. Efficacy of an imidacloprid/flumethrin collar against fleas, ticks, mites and lice on dogs

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    Stanneck Dorothee

    2012-05-01

    Full Text Available Abstract Background The studies reported here were conducted to ascertain the efficacy of imidacloprid/flumethrin incorporated in a slow-release matrix collar, against infestations of dogs by fleas, ticks, mites and lice. Efficacy was evaluated against the flea Ctenocephalides felis felis, the ticks Rhipicephalus sanguineus, Ixodes ricinus, Ixodes scapularis, Dermacentor reticulatus and Dermacentor variabilis, the mite Sarcoptes scabiei and the biting louse Trichodectes canis. Methods Groups of collar-treated dogs (n = 7–10 were infested with fleas and/or ticks at monthly intervals at least, over a period of up to 8 months. Efficacy against fleas was evaluated 24 to 48 h after treatment and 24 h after each re-infestation. Efficacy against ticks was evaluated at 48 h (acaricidal, 6 h (repellent and 48 h (sustained after infestation. The effect of regular shampooing or immersion in water on the efficacy of the collars was also tested. Efficacy against flea larvae was assessed by incubating blanket samples after dog contact with viable flea eggs. Effectiveness against lice and mites was evaluated after treatment of naturally infested animals. With the exception of the mites, efficacy was calculated by comparison with untreated negative control groups. Results Efficacy against fleas (24 h generally exceeded 95%, and against flea larvae it exceeded 99% for 8 months. Sustained acaricidal (48 h efficacy, covering a period of 8 months was 100% against I. ricinus, starting 2 days after treatment (in vivo, and 100% against I. scapularis (in vitro, above 97% against R. sanguineus, generally above 97% against D. reticulatus and above 90% for D. variabilis. Repellent (6 h efficacy 2 days after treatment and continuing for 8 months was consistently 100% against I. ricinus, and above 90% against R. sanguineus. Regular shampooing affected efficacy against fleas and ticks to a lesser extent than regular immersion in water. The

  16. GC×GC-TOFMS Analysis of Essential Oils Composition from Leaves, Twigs and Seeds of Cinnamomum camphora L. Presl and Their Insecticidal and Repellent Activities.

    Science.gov (United States)

    Jiang, Hao; Wang, Jin; Song, Li; Cao, Xianshuang; Yao, Xi; Tang, Feng; Yue, Yongde

    2016-03-28

    Interest in essential oils with pesticidal activity against insects and pests is growing. In this study, essential oils from different parts (leaves, twigs and seeds) of Cinnamomum camphora L. Presl were investigated for their chemical composition, and insecticidal and repellent activities against the cotton aphid. The essential oils, obtained by hydrodistillation, were analyzed by GC×GC-TOFMS. A total of 96 components were identified in the essential oils and the main constituents found in the leaves and twigs were camphor, eucalyptol, linalool and 3,7-dimethyl-1,3,7-octatriene. The major components found in the seeds were eucalyptol (20.90%), methyleugenol (19.98%), linalool (14.66%) and camphor (5.5%). In the contact toxicity assay, the three essential oils of leaves, twigs and seeds exhibited a strong insecticidal activity against cotton aphids with LC50 values of 245.79, 274.99 and 146.78 mg/L (after 48 h of treatment), respectively. In the repellent assay, the highest repellent rate (89.86%) was found in the seed essential oil at the concentration of 20 μL/mL after 24 h of treatment. Linalool was found to be a significant contributor to the insecticidal and repellent activities. The results indicate that the essential oils of C. camphora might have the potential to be developed into a natural insecticide or repellent for controlling cotton aphids.

  17. POSSIBILITIES TO USE NATURAL EXTRACTS FROM MEDICINAL AND AROMATIC PLANTS (MAP LIKE BOTANICAL REPELLENT OR INSECTICIDE COMPOUNDS AGAINST PEST INSECTS IN ECOLOGICAL CROPS (II

    Directory of Open Access Journals (Sweden)

    Irina IONESCU-MĂLĂNCUŞ

    2013-12-01

    Full Text Available Botanical insecticides have long been touted as attractive alternatives to synthetic chemical insecticides for pest management because botanicals reputedly pose little threat to the environment or to human health. The body of scientific literature documenting bioactivity of plant derivatives to arthropods pests continues to expand i.e. repellents based on essential oils extracted from Chenopodium ambrosioides, Eucalyptus saligna, Rosmarinus officinalis to mosquitoes, or cinnamon oil, sandalwood oil and turmeric oil are previously reported as insect repellents evaluatede in the laboratory conditions. With the constantly increasing problems of insecticide resistance and increasing public concerns regarding pesticide safety, new, safer active ingredients are becoming necessary to replace existing compounds on the market. The present study carried out in the period 2010-2012 comprises a review of two insect repellents, followed by some new research conducted in our laboratory on plant-derived insect repellents. The two alkaloids tested against the Colorado potato beetle, Leptinotarsa decemlineata Say in laboratory conditions was obtained by water and alchohol extraction from two vegetal species, Cichorium intybus L. (Asterales:Asteraceae and Delphinium consolida L. (Ranales:Ranunculaceae. The tests carried out in laboratory and field experimentally plots under cages permit to evaluate several other compounds for repellent activity of lacctucin alkaloids.

  18. Use of repellents for honeybees (Apis mellifera L. in vitro in the yellow passion-fruit (Passiflora edulis Deg crop and in confined beef cattle feeders

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    D. Nicodemo

    2004-01-01

    Full Text Available The presence of Apis mellifera in places such as candy and soft drink factories, restaurants, and ice-cream shops has been a concern to many people. In the yellow passion-fruit crop, Apis mellifera is able to collect all anther pollen but has no active role in pollination. Honeybees also visit animal feeders with chopped sugar cane, preventing the cattle from eating. This work studied the effect of natural and synthetic substances as Apis mellifera repellents in vitro in the yellow passion-fruit crop and in confined beef cattle feeders. There was a repellent effect in vitro with the following substances in decreasing order: tobacco, rue, garlic, parsley, and century plant extracts; average effect was twenty-five minutes. For the yellow passion-fruit, garlic extracts and 2-heptanone were equally efficient with a two and a half hour repellent action. Garlic and citronella extracts were efficient in repelling Apis mellifera from confined beef cattle feeder for six hours. Garlic repellent action was higher than citronella.

  19. Repellent effect of two kinds of phytochemicals on mouse%2种植物素对小鼠的驱避作用研究

    Institute of Scientific and Technical Information of China (English)

    钟平生; 谢彩玉; 张颂声; 郭国汉

    2011-01-01

    目的 研究2种植物素辣椒素和肉桂酰胺对小鼠的驱避效果.方法采用驱避率评价其驱避效果.结果辣椒素和肉桂酰胺均有很强的驱避效果,且随着作用时间的增长,驱避效果越强.投喂第1天,小鼠对1%、3%和5%辣椒素毒饵均有取食,驱避率分别为99.74%、98.66%、99.18%;第2天,小鼠仅取食少许5%辣椒素毒饵,驱避率为99.79%;第3~5天驱避率均达到100%;而8%辣椒素毒饵在5d内对小鼠的驱避率均达100%.肉桂酰胺各浓度毒饵在投喂第1天,小鼠均有取食,其中30%肉桂酰胺的驱避作用最强,驱避率为99.09%;第2天驱避率达100%的有25%和30%肉桂酰胺;在第3~5天中,除第3天5%肉桂酰胺外,其余处理的驱避率均达100%.结论在实际防鼠工作中,考虑到成本和驱避效果,可推荐使用1%辣椒素与8%肉桂酰胺.%Objective To study the repellent effect of two kinds of phytochemicals on mouse. Methods Assessing their repellent effect by the repellent rate. Results Capsaicinoids and cinnamide had strong repellent effects, and with the time growth, repellent rate got stronger. On the first day fed by 1% ,3% and 5% capsaicinoids, the repellent rate were 99.74% , 98.66% , 99. 18%. On the second day, the repellent rate on mouse fed by a little 5% capsaicinoids bait was 99.79% , and from the 3th to 5th day, the repellent rate had all grew to 100%. And the repellent rate to the mouse fed by 8% capsaicinoids bait always reached 100% in 5 days. On the first day fed by all kinds concentration of cinnamide, each group mouse had been fed by little bait, of which 30% cinnamide had the highest repellent rate( 99.09% ). On the second day, the repellent rate of 25% and 30% cinnamide all reached 100%. From the 3th to 5th day, except to the treat of 5% cinnamide on the third day, repellent rate of the others was 100%. Conclusion In practical rat proof, considering the costs and repellent effects, it is

  20. Effect of climatic conditions on the development of soil water repellency in soils treated with the wastewater of the olive oil production

    Science.gov (United States)

    Schaumann, Gabriele E.; Peikert, Benjamin; Tamimi, Nesreen; Steinmetz, Zacharias; Fischer, Jonas; Bibus, Daniel; Marei Sawalha, Amer; Dag, Arnon

    2014-05-01

    The disposal of untreated wastewater on soil can induce severe water repellency. The final degree of water repellency may strongly depend on the environmental conditions prevailing during and after disposal. Also unpolluted soil can develop severe water repellency upon exposure to extreme heat or draught events. The induced water repellency can be either persistent or of transient nature. However, the underlying mechanisms are not yet completely understood. The objective of this study was to investigate how climatic conditions determine the development and persistence of water repellency following wastewater disposal. Our hypothesis was that amphiphilic organic wastewater compounds physically sorb onto surfaces, which renders them hydrophobic. Depending on temperature and moisture, those compounds are degraded, chemically incorporated into SOM, or irreversibly sorbed to soil particles during the time after the first waste water-soil contact. According to our hypothesis, biological communities favor degradation and transformation of OM of waste water into SOM under moist soil conditions. This would reduce the initial hydrophobization. In contrast, drying irreversibly renders soil hydrophobic and phytotoxic due to immobilization of OMW OM in the soil. To test these hypotheses, we investigated effects of olive mil wastewater (OMW), the effluent originating from olive oil production, directly applied to soil. In Israel and Palastine, olive oil production generates large amounts of OMW within a short period of time between November and January. As sewage facilities do not accept OMW, it is often disposed onto soil, which leads to severe soil and groundwater pollution. If the above mentioned hypotheses match, pollution and hydrophobization might be minimized if the wastewater is discharged at the right time of the year. In order to test this, we conducted field (2-3 years) and laboratory (60 days) experiments in Israel (Gilat, arid climate) and in the West Bank (Bait