Thesis (Ph. D.)--University of Melbourne, 2005. / Title from PDF title page (viewed on Dec. 3, 2006). Includes bibliographical references (p. 123-139).

Os afídeos são importantes pragas na agricultura, principalmente por serem vetores de fitovírus, os quais são transmitidos geralmente no momento da picada de prova. Além disso, os afídeos também removem os aminoácidos nitrogenados das plantas ao se alimentarem no floema e injetam substâncias presentes na saliva, que interferem na fisiologia da planta. Entre as táticas de controle para o manejo integrado desses insetos, pode-se citar o emprego de inseticidas químicos ou botânicos e o uso de produtos repelentes que tornam as plantas pulverizadas não atrativas, evitando que pulgões pousem e se alimentem normalmente da planta. Nesse contexto, objetivou-se estudar a bioatividade de extratos orgânicos das Meliaceae Trichilia pallida, Trichillia claussenii,Trichilia catigua, Toona ciliata e Guarea guidonia e dos óleos essenciais das Piperaceae Piper amalago, Piper umbellatum, Piper claussenianum e Piper sp. em relação a pulgões, utilizando como espécie-modelo R. maidis. Os extratos orgânicos das Meliaceae foram obtidos, por maceração, com o uso dos solventes hexano, diclorometano e etanol, nessa sequência de extração. O extrato hexânico de T. pallida foi o que apresentou a maior atividade aficida, sendo então selecionado para fracionamento por cromatografia de coluna rápida utilizando, sequencialmente, os solventes hexano, acetato de etila e metanol. Entre as frações, a hexânica causou a maior mortalidade, sendo selecionada para a determinação dos modos de ação sobre R. maidis. A referida fração não apresentou ação de contato e nem ação neurotóxica; entretanto, foi constatada ação translaminar. No ensaio com Electrical Penetration Graph - EPG, os insetos apresentaram maior dificuldade para se alimentar. Entre as Piperaceae, a maior repelência e mortalidade a R. maidis foi causada por P. claussenianum, cujo óleo essencial foi então selecionado para os testes subsequentes. Sua atividade inseticida ocorreu por contato, causando rápida mortalidade, acreditandose, assim, tratar-se de um efeito neurotóxico; não foi constatado, entretanto, efeito fumigante. Quanto às alterações comportamentais, constatou-se efeito repelente sobre alados por meio de teste com olfatômetro e o efeito fagodeterrente com uso do EPG. Com base nos resultados, conclui-se que entre os extratos orgânicos e óleos essenciais testados, a fração hexânica do extrato hexânico de T. pallida apresenta substâncias com atividade inseticida sobre R. maidis, sendo uma possível fonte para síntese de novos inseticidas e que o óleo essencial de P. claussenianum pode ser utilizado diretamente no controle de pulgões ou servir de fonte para a identificação de moléculas inseticidas para a síntese. / Aphids are important pests in agriculture mainly because they are vectors of phytovíruses, which are normally transmitted during the aphids probe. In addition, aphids not only remove amino-nitrogen from the plants while feeding in the phloem but also inject substances present in their saliva, which interfere in plant physiology. Among the strategies for the integrated management of these insects, we can state the use of chemical or botanical insecticides as well as repellents which turn the plants into nonattractive ones, thus avoiding that aphids land and feed normally from the plant. Therefore, we studied the bioactivity of organic extracts from the Meliaceae plants Trichilia pallida, Trichilia claussenii, Trichilia catigua, Toona ciliata and Guarea guidonia and essential oils from the Piperaceae plants Piper amalago, Piper umbellatum, Piper claussenianum and Piper sp. against aphids, using R. maidis as a model species. Organic extracts from Meliaceae were obtained by maceration technique using hexane, dichloromethane and ethanol solvents, in this sequence of extraction. Hexanic extract from T. pallida provoked the highest activity against aphids being chosen for the fractionation using a chromatographic column with fast flow and using hexane, ethyl acetate and methanol solvents, in this sequence. Hexanic fraction provoked the highest mortality among the fractions evaluated being chosen in order to understand its modes of action on R. maidis. This fraction had neither mode of action by contact nor neurotoxic action; however, its translaminar action was proved. Using the Electrical Penetration Graph - EPG, we observed that most of the insects had difficulty to feed themselves. Among the Piperaceae plants, the highest repellency and mortality of R. maidis was caused by P. claussenianum which was selected for the subsequent assays. Its insecticidal activity occurred through contact causing a fast mortality perhaps due to a neurotoxic effect. Nevertheless, a fumigant effect was not observed. With regard to behavioral changes, a repellent effect was proven on alates through olfactometer assay and a phagodeterrent effect was proven using EPG assay. According to the results, we concluded that among the organic extracts and essential oils evaluated, the hexanic fraction from hexanic extract from T. pallida contains substances with insecticidal activity against R. maidis being a potential source for synthesis of new insecticides while the essential oil from P. claussenianum may be used both to control aphids and to be a source for identification of insecticidal molecules aiming their synthesis.

Os afídeos são importantes pragas na agricultura, principalmente por serem vetores de fitovírus, os quais são transmitidos geralmente no momento da picada de prova. Além disso, os afídeos também removem os aminoácidos nitrogenados das plantas ao se alimentarem no floema e injetam substâncias presentes na saliva, que interferem na fisiologia da planta. Entre as táticas de controle para o manejo integrado desses insetos, pode-se citar o emprego de inseticidas químicos ou botânicos e o uso de produtos repelentes que tornam as plantas pulverizadas não atrativas, evitando que pulgões pousem e se alimentem normalmente da planta. Nesse contexto, objetivou-se estudar a bioatividade de extratos orgânicos das Meliaceae Trichilia pallida, Trichillia claussenii,Trichilia catigua, Toona ciliata e Guarea guidonia e dos óleos essenciais das Piperaceae Piper amalago, Piper umbellatum, Piper claussenianum e Piper sp. em relação a pulgões, utilizando como espécie-modelo R. maidis. Os extratos orgânicos das Meliaceae foram obtidos, por maceração, com o uso dos solventes hexano, diclorometano e etanol, nessa sequência de extração. O extrato hexânico de T. pallida foi o que apresentou a maior atividade aficida, sendo então selecionado para fracionamento por cromatografia de coluna rápida utilizando, sequencialmente, os solventes hexano, acetato de etila e metanol. Entre as frações, a hexânica causou a maior mortalidade, sendo selecionada para a determinação dos modos de ação sobre R. maidis. A referida fração não apresentou ação de contato e nem ação neurotóxica; entretanto, foi constatada ação translaminar. No ensaio com Electrical Penetration Graph - EPG, os insetos apresentaram maior dificuldade para se alimentar. Entre as Piperaceae, a maior repelência e mortalidade a R. maidis foi causada por P. claussenianum, cujo óleo essencial foi então selecionado para os testes subsequentes. Sua atividade inseticida ocorreu por contato, causando rápida mortalidade, acreditandose, assim, tratar-se de um efeito neurotóxico; não foi constatado, entretanto, efeito fumigante. Quanto às alterações comportamentais, constatou-se efeito repelente sobre alados por meio de teste com olfatômetro e o efeito fagodeterrente com uso do EPG. Com base nos resultados, conclui-se que entre os extratos orgânicos e óleos essenciais testados, a fração hexânica do extrato hexânico de T. pallida apresenta substâncias com atividade inseticida sobre R. maidis, sendo uma possível fonte para síntese de novos inseticidas e que o óleo essencial de P. claussenianum pode ser utilizado diretamente no controle de pulgões ou servir de fonte para a identificação de moléculas inseticidas para a síntese. / Aphids are important pests in agriculture mainly because they are vectors of phytovíruses, which are normally transmitted during the aphids probe. In addition, aphids not only remove amino-nitrogen from the plants while feeding in the phloem but also inject substances present in their saliva, which interfere in plant physiology. Among the strategies for the integrated management of these insects, we can state the use of chemical or botanical insecticides as well as repellents which turn the plants into nonattractive ones, thus avoiding that aphids land and feed normally from the plant. Therefore, we studied the bioactivity of organic extracts from the Meliaceae plants Trichilia pallida, Trichilia claussenii, Trichilia catigua, Toona ciliata and Guarea guidonia and essential oils from the Piperaceae plants Piper amalago, Piper umbellatum, Piper claussenianum and Piper sp. against aphids, using R. maidis as a model species. Organic extracts from Meliaceae were obtained by maceration technique using hexane, dichloromethane and ethanol solvents, in this sequence of extraction. Hexanic extract from T. pallida provoked the highest activity against aphids being chosen for the fractionation using a chromatographic column with fast flow and using hexane, ethyl acetate and methanol solvents, in this sequence. Hexanic fraction provoked the highest mortality among the fractions evaluated being chosen in order to understand its modes of action on R. maidis. This fraction had neither mode of action by contact nor neurotoxic action; however, its translaminar action was proved. Using the Electrical Penetration Graph - EPG, we observed that most of the insects had difficulty to feed themselves. Among the Piperaceae plants, the highest repellency and mortality of R. maidis was caused by P. claussenianum which was selected for the subsequent assays. Its insecticidal activity occurred through contact causing a fast mortality perhaps due to a neurotoxic effect. Nevertheless, a fumigant effect was not observed. With regard to behavioral changes, a repellent effect was proven on alates through olfactometer assay and a phagodeterrent effect was proven using EPG assay. According to the results, we concluded that among the organic extracts and essential oils evaluated, the hexanic fraction from hexanic extract from T. pallida contains substances with insecticidal activity against R. maidis being a potential source for synthesis of new insecticides while the essential oil from P. claussenianum may be used both to control aphids and to be a source for identification of insecticidal molecules aiming their synthesis.

Background. Traditional plant use was studied in Lao PDR. Research focused on medicinal plant use by the Brou, Saek and Kry ethnic groups, traditional plant repellents against parasitic arthropods and leeches, and the phylogeny and biogeography of the medicinally-important snake gourd genus (Trichosanthes, Cucurbitaceae).  Methods. The ethnobiology research used a combination of structured interviews, village surveys, botanical collecting, hydro-distillation, GC-MS analysis, literature studies, and laboratory experiments. The plant systematics research used a combination of morphological studies, molecular biology laboratory work, and phylogenetic, dating and biogeographical analysis.  Results. Informants reported the use of close to 100 species to repel arthropods and leeches, many of which have constituents with documented efficacy.  Brou, Saek and Kry informants use over 75 plant species for women’s healthcare, mainly during the postpartum period for steam sauna, steam bath, hotbed, mother roasting, medicinal decoctions and infusions, and postpartum diet.  A molecular phylogeny of Trichosanthes and Gymnopetalum using a broad sampling of ~60% of their species and 4756 nucleotides of nuclear and plastid DNA shows that Gymnopetalum is nested within Trichosanthes. Fossil-calibrated Bayesian molecular dating of the Trichosanthes phylogeny reveals an early Oligocene origin of the genus, and many of the extant sections originating and diversifying during the Miocene. Biogeographical analysis shows a likely East or South Asian origin of Trichosanthes, with lineages diversifying and spreading throughout Australasia from the early Pliocene to the Pleistocene.  Discussion. Traditional plant use in Lao PDR is common and widespread. The presence among the repellent species of economical alternatives to costly synthetic repellents is tenable, and the subject of ongoing studies.  Postpartum traditions and medicinal plant use are essential parts of childbirth and postpartum recovery in these ethnic groups, and many other groups in Lao PDR. Efforts to improve maternal healthcare and reduce maternal and infant mortality need to integrate these traditions with modern notions of healthcare to achieve wider adoption. Documenting all possible uses of commonly used medicinal plant species shows that similarity in use between these ethnic groups is relatively low considering that they share, and have shared for many generations, the same environment and resources. A lack of effective cures leads to a process of continuous innovation, where effective cures are shared between cultures, but remedies of only cultural importance, or those under evaluation are culture-specific.  The Trichosanthes phylogeny implies the merging of Gymnopetalum into Trichosanthes, and this is done using available names or new combinations. A synopsis of Trichosanthes, the new combinations, and a revision of the species in Australia, are made and presented.  Conclusions. Traditional plant use is widespread in Lao PDR, and of significance to many people as a source of primary healthcare and inexpensive repellents. The important medicinal plant genus Trichosanthes includes Gymnopetalum, and has a complex biogeographic history with multiple colonization events of Australasia.

Haematophagous parasites and disease vectors such as leeches, ticks, mites, lice, bed bugs, mosquitoes, and myiasis-causing fly larvae are common health problems in Lao Peoples Democratic Republic (Lao PDR). A main aim of my field work in Lao PDR in 2006-2010 was to document traditional knowledge among different ethnic groups about plants that people use to repel or to kill blood-feeding invertebrates. We carried out structured interviews in 66 villages comprising 17 ethnic groups, covering a range of ethnic group, throughout Lao PDR and recorded a total of 92 plant species - in 123 different plant-ectoparasite combinations - that are used as traditional repellents and/or as “pesticides” to kill "pest" invertebrates. Traditional use was confirmed in the scientific literature for 74 of these plant species, and for an additional 13 species based on literature on closely related species. We concluded that repellents and pesticides from many plant species are commonly used in the Lao countryside. We also investigated traditionally used Lao plants for their activity to repel or to kill certain disease vectors and parasites. Target organisms were mosquitoes (Diptera, Culicidae), fly larvae (Diptera, Cyclorrhapha) in fermented fish production, and terrestrial blood-sucking leeches (Hirudinea, Haemadipsidae). The potential mosquito repellent activities of essential oils of Croton roxburghii (Euphorbiaceae), Hyptis suaveolens (Lamiaceae), and Litsea cubeba (Lauraceae) were evaluated in the field near Vientiane. Oils at concentrations of 1.7-6.7 µg/cm2 were significantly repellent to Aedes, Armigeres and Culex attracted to human baits. The activities against fly larvae, infesting fermenting fish, of three plant species, Tadehagi triquetrum (Fabaceae), Uraria crinita (Fabaceae) and Bambusa multiplex (Poaceae) were investigated: When fresh material of the plants was added on top of fermenting fish infested with fly larvae significant proportions of the larvae were repelled or killed. The total protective effect, i.e., repellent and killing effect combined, of T. triquetrum, U. crinita, and B. multiplex was 60-83 %, 77-90 %, and 60-93 %, respectively. Field evaluation of the potential leech repellent activities of water extracts of Sapindus rarak (Sapindaceae), Catunaregam spathulifolia (Rubiaceae) and Vernonia elaeagnifolia, (Asteraceae) impregnated on stockings and worn by persons in two leech-infested biotopes revealed leech repellent activities of 82.6%, 62.6% and 63.0%, respectively. The corresponding repellencies of deltamethrin and diethyl-3-methyl-benzamide (DEET) were 73.1% and 88.4%, respectively. Identification of the active components in certain of the plants with the ultimate aim to develop more optimal, less costly repellents, insecticides, acaricides, and anti-leech compounds as alternatives to synthetic repellents and pesticides against blood-feeding insects, ticks, mites, and leeches is in progress.

Les façades des nouveaux bâtiments et des bâtiments existants sont altérées par la pénétration de l'eau. Afin de protéger les bâtiments et surfaces exposées aux intempéries, des traitements contenant des agents hydrophobes doivent être appliqués.<p>Les traitements utilisés à l’heure actuelle sont des traitements de surface qui se dégradent au cours du temps. L'agent hydrophobe, présent en surface, est soumis à des conditions très rudes telles que des rayonnements ultraviolets, de grandes variations de température, de l'abrasion .qui réduisent l’efficacité et la durabilité des traitements. La plupart des traitements aujourd'hui disponibles, fournisse une barrière efficace au passage de l’eau à court terme, mais doivent donc être réappliqués régulièrement. <p>Le projet de recherche, présenté ici, traite de la mise en place d'un traitement de masse de matériaux cimentaires utilisés dans la protection de structures (joints, crépi .). Ce traitement devrait offrir une protection à long terme, mais ne devrait pas modifier de manière significative les propriétés mécaniques des matériaux. <p>Les avantages d'un traitement de masse sont évidents. Seule une petite partie de l'agent hydrophobe est exposée et dégradée par les conditions climatiques et l'abrasion de surface ne porte pas atteinte à l'intégrité du traitement.<p>Une étude fondamentale a été menée afin d'étudier l'influence de l'incorporation d´agents à base de silicium sur les processus d'hydratation des ciments Portland et de comprendre leur mode d'action. Deux agents (alpha,omega dihydroxypolydimethylsiloxane et n-octyltriethoxysilane) et deux ciments Portland (ordinaire et blanc CEM I 42,5N) ont été choisis et étudiés. Trois modes d´introduction (liquides purs, émulsions et granules) ont été mis en œuvre et comparés. <p>Le but est de déterminer les meilleures conditions pour obtenir un traitement efficace et durable tout en préservant les propriétés mécaniques. Les résultats d'absorption d'eau par capillarité et de perméabilité à la vapeur d’eau sont prometteurs et les essais mécaniques sur mortiers n’ont pas montré de diminutions significatives des résistances mécaniques. <p><p>La microstructure et la progression de l'hydratation des matrices cimentaires adjuvantées et de référence, ont été caractérisées par calorimétrie à conduction, par calorimétrie différentielle à balayage couplée à la thermogravimétrie, par spectroscopie infra-rouge, par diffraction des rayons X, par porosimétrie au mercure, et par microscopie électronique à balayage.<p><p>La durabilité des matériaux adjuvantés a été étudiée afin de montrer la pertinence des traitements ainsi que l'évaluation de la progression de l'hydratation. Les performances hydrofuges ainsi que l’évolution de la microstructure, à l’issue des différents vieillissements artificiels et naturels, ont été déterminées.<p>Les mortiers mis en œuvre ont été soumis à des vieillissements artificiels simulant des conditions proches de celles rencontrées en pratique (tels que des cycles rayonnements UV, pluie, sel, gel/dégel…). Une amélioration de la durabilité des mortiers adjuvantés a été observée. Les résultats sont très encourageants et confirment l'intérêt d’un tel traitement dans la masse.<p><p>/Protection of cement-based materials means above all, moisture protection because water is primarily responsible for inducing damaging physical and chemical processes in building materials. In most cases, water repellents are applied either directly during the construction or insulation process; or as a post-treatment of the exposed surfaces in order to protect the buildings from further decay. A new way is to develop a bulk treatment for cement-based materials which should provide a long term protection without modifying the mechanical properties of the cementitious materials. <p>The advantages of a bulk treatment are obvious i.e. only a small part of the hydrophobic agent is exposed and degraded by the UV. In addition, surface abrasion does not affect the integrity of the treatment. <p><p>A fundamental study was initiated to investigate the influence of the incorporation of two active silicon-based agents (already used as post-building treatments) on the hydration processes of Portland cements and to understand the involved mechanisms of interaction. <p>Two agents (alpha,omega dihydroxypolydimethylsiloxane and n-octyltriethoxysilane) and two Portland cements (Ordinary and White Portland Cement CEM I 42,5N) were chosen and studied. Three incorporation modes (pure liquids, water emulsions and granules) were investigated. The effects of the three modes were compared.<p>The aim was to determine the best conditions for an efficient and sustainable treatment preserving the mechanical properties of the materials. <p>The results of capillary water penetration and water vapor permeability are promising and are not accompanied by a significant decrease of the mechanical performances<p><p>The microstructure and progression of hydration of admixtured cement pastes were characterized by conduction calorimetry, differential scanning calorimetry, thermo-gravimetry, infra-red spectroscopy, X-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy. <p>In addition, the durability of water-repellent additives and of the admixtured cement was studied in order to show the relevance of the treatments as well as the assessment of the progression of hydration and the type of products that were developed. <p>Mortar specimens were submitted to artificial ageing cycles such as freeze-thaw cycles, ultraviolet cycles and rain-sun cycles. <p>The general trend is an improvement of the durability of admixtured mortars. <p>The results are very encouraging and confirm the interest of the bulk mortar treatment. <p><p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

”Durable water repellents (DWR) är textilimpregneringar som bidrar med vattenavvisande egenskaper som håller länge på funktionella tyg. Tyvärr är dessa hydrofobiska ytbehandlingar vanligtvis en källa till skadliga och persistenta kemikalier och de även är producerade från fossilbaserade resurser. Eftersom medvetenheten kring de här problemen har ökat, har innovativa, miljövänliga och biologiskt nedbrytbara alternativ tagits fram. Hittills finns dock inga produkter gjorda av 100% förnybara råvaror. I ett försök att utveckla en biobaserad, icke-giftig DWR som aktiveras under milda förhållanden, lades fokus på utveckling av en lagringsstabil sprayimpregneringsprodukt för hemmabruk. Vid formulering av emulsionerna/dispersionerna utvärderades en stor mängd biobaserade och kommersiellt tillgängliga hydrofobiska och amfifila molekyler med avseende den vattenavvisande effekt som de bidrog med på den behandlade textilen. Samtidigt bedömdes de producerade formuleringarna noggrant för att skapa förståelse om effekterna från ingredienserna och deras relation till produktens stabilitet. De kandidatprodukter som valdes ut och undersöktes vidare hade lovande vattenavvisande egenskaper och visade rimlig hållbarhetstid på åtminstone en månad i 40 °C. Standardiserade sprayscores på 3 (där 1 är sämst och 5 är bäst) nåddes efter 24 timmars hängtorkning i rumstemperatur. Dessutom uppnåddes sprayscore på 5 efter en kort, icke-industriell torktumling på låg temperatur och den behölls efter minst tio tvättar på syntetiska textiler. Utvalda produkter påverkade inte märkbart tygets andningsförmåga och majoriteten hade ingen influens på textilens mjukhet och färg. Förutom uppskalningsexperiment och partikelstorleksmätningar, granskades resultat med en tillämpningsstudie av formuleringarna på femton olika tygtyper. Produkternas effekter på utseende och känsla dokumenterades för de olika textilierna. Egenskaper som kontaktvinklar, sprayscores och tvättbeständighet bestämdes och jämfördes med en kommersiellt tillgänglig produkt. / Durable water repellents (DWR) are textile finishes that provide long-lasting water repelling properties to functional garments. However, these hydrophobic finishes are commonly a source of polluting and persistent chemicals and are produced from fossil resources. As a result of increasing awareness, innovation towards environmentally friendly and biodegradable alternatives has progressed, yet no 100% renewable sourced products are available. In an attempt to create a bio-based, non-toxic DWR, that is curable under mild conditions, focus was put on the development of a shelf stable spray impregnation product intended for consumer use. By formulating dispersion/emulsion systems, a wide variety of commercially available, renewable sourced amphiphilic and hydrophobic molecules were evaluated on their effect on the water repelling performance of treated textile fabrics. Simultaneously, the produced systems were assessed carefully to create understanding on the effect of substances and their corresponding ratios on the stability. Promising candidate products that were selected for further investigation showed reasonable stability for 1 month at 40 °C. Industrial standard spray ratings of 3 (where 1 is worst and 5 is best) after hang drying at room temperature could be reached within 24 hours. On top of that, spray ratings of 5 could be reached after short time, non-industrial tumble drying at low temperatures, which could even be retained for at least ten laundering cycles on synthetic textiles. The selected finishes did not have a measurable effect on the breathability of the treated fabrics, while the majority did not considerably affect the hands-feeling or colour of the textiles. Besides several scaling up experiments and particle size measurements, extrapolation of the findings was carried out by testing the developed formulations on fifteen different types of textiles. Effects on appearance and feel were documented, additionally, contact angle, spray score, and wash durability were determined and compared with a commercially available product.

As doenças transmitidas por mosquitos representam uma das maiores causas de morbidade e mortalidade em todo o mundo, principalmente em países tropicais. O uso tópico de repelentes em determinadas situações torna-se a única alternativa para evitar o ataque por estes artrópodes. Os óleos de andiroba (Carapa guianensis) e copaíba (Copaifera sp.) possuem relatos de atividade repelente de insetos, podendo representar uma alternativa segura ao uso de repelentes sintéticos que apresentam riscos de toxidade em determinados casos. O objetivo desta pesquisa foi desenvolver nanoemulsões O/A, utilizando como fase oleosa os óleos de copaíba e andiroba, e testar in vivo a atividade repelente das mesmas frente ao mosquito Aedes aegypti, realizando um estudo comparativo com repelente comercial a base de DEET. Ensaios para avaliar os parâmetros físico-quimicos envolvidos no processo de obtenção das nanoemulsões, e estudos de sua estabilidade preliminar, também foram realizados. Os resultados apontam a viabilidade do método de emulsificação utilizando baixa energia na formação de nanoemulsões. A temperatura, velocidade de agitação, ordem de adição dos componentes e quantidade de tensoativo na formulação, demonstraram ser fatores críticos no processo. Foi possível obter três nanoemulsões estáveis com tamanho de glóbulos inferior a 300nm, sendo uma com 15% de óleo de andiroba; outra contendo 10% de óleo de copaíba e a terceira associando 10% de andiroba e 5% de copaíba. No ensaio repelente utilizando voluntários humanos, foi constatado que as nanoemulsões compostas de óleo de andiroba e óleo de andiroba adicionado de óleo de copaíba são capazes de repelir mosquitos Aedes aegypti por um período de 30 minutos, sendo estes resultados estatisticamente significativos em relação ao grupo controle. / Mosquito-borne diseases remain a major source of illness and death worldwide, particularly in tropical countries. Mosquito repellents may be one of the most effective tools for protecting humans from vector-borne diseases. In many circumstances, applying repellent to the skin may be the only feasible way to protect against insect bites. The oils from andiroba (Carapa guianensis seed oil) and copaíba (Copaifera oil) have been studied as possible mosquito repellents. These products can be represents a safe alternative in the use of synthetic repellent, that have toxic risks in some cases. The goals of this research were to development O/A nanoemulsion using andiroba seed oil and copaíba oil and test their repellent action in vivo against bites Aedes aegypti. This study compares the repel effectiveness of nanoemulsions developed in relation to the market product of DEET. Assays to evaluate the parameters involved physicist-chemistries in the process of attainment of the nanoemulsions, and studies of its preliminary stability, had been also carried through. The results showed viability of the emulsification method using low energy in the formation of nanoemulsions. The temperature, speed of agitation, order of addition of the components and amount of surfactant in the formulation, had demonstrated to be critical factors in the process. In this study, it was possible get three stable nanoemulsion with droplets size less than 300nm, using: 15% andiroba seed oil; 10% copaiba oil and mix of andiroba seed oil (10%) and copaíba oil (5%). The repellent test with human voluntaries proves that nanoemulsions with andiroba seed oil, and the mix of andiroba seed oil and copaiba oil, are able to repel Aedes aegypti for 30 minutes period, witch are statistic signification compared to the control group.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Water can be supplied to many arid areas by harvesting the precipitation that falls on artificially prepared water-repellent soil catchments. The failure, in 1973, of wax-treated water harvesting catchment led to this study which indicates that the failure was due to swelling and shrinking of the treated soil which caused complete structural breakdown and loss of repellency. The laboratory freeze-thaw studies demonstrated that the smoother the plot, the less chance of freeze-thaw damage. Generally, coarser-textured soil can withstand freeze-thaw cycles better than finer-textured soils. Soil properties, other than texture, may also affect resistance to damage by freeze-thaw cycles. Increasing the repellent application rate may improve resistance to breakdown.

Les huiles essentielles de citronnelle (Cymbopogon citratus), de géranium (Pelargonium graveolens) et de vétiver (Vetiveria zizanioides) sont utilisées partout dans le monde pour leur activité répulsive contre les principaux vecteurs (moustiques, tiques) de maladies infectieuses chez l'Homme (paludisme, chikungunya, …). L'application cutanée de ces produits naturels pour éviter le contact avec un vecteur n'avait pas été encore envisagée comme moyen de limiter les premiers stades de l’infection par l'agent pathogène transmis par le vecteur. Pour vérifier cette hypothèse, les travaux ont été consacrés à la mise en place d'un cadre structuré pour la réévaluation chimique et biologique des trois huiles essentielles sur le modèle du virus du Ross River (alphavirus) de la même famille que le virus du Chikungunya. La caractérisation chimique des huiles essentielles avec une technique de haute résolution (GC×GC/TOF-MS) a permis d'établir leur profil chémotypique précis. L'utilisation de marqueurs spécifiques (clones moléculaires du virus) a permis d'établir l'inhibition de la réplication virale en fonction des conditions d'application des huiles essentielles de géranium et citronnelle. Ces résultats suggèrent l'intérêt d’une huile essentielle répulsive dans les premiers stades d'une infection par un vecteur. À ce titre, l'étude comparative établit la haute valeur ajoutée de l'huile essentielle de géranium et oriente la recherche de nouveaux anti-infectieux naturels vers des complexes riches en monoterpènes. / Essential oils of citronella (Cymbopogon citratus), geranium (Pelargonium graveolens) and vetiver (Vetiveria zizanioides) are used worldwide as topical repellent against the main vectors (mosquitoes, ticks) of human infectious diseases (Malaria, chikungunya, …). Skin treatment with these natural products, initially to avoid contact with the vector had not yet been considered as a way to disrupt the early stages of infection when the repelling action fails. To check this hypothesis, a structured framework has been performed for the chemical and biological re-evaluation of the three essential oils. The latter was tested against Ross River virus (alphavirus) that belongs to the same family of Chikungunya virus. Analysis of essential oils using a high-resolution technique (GC × GC / TOF-MS) resulted in a more accurate chemotypical profile of the local production. The use of specific markers (molecular clones of the virus, Saclay CEA) allowed to establish the inhibition of viral replication depending of the conditions of geranium and citronella essential oils application. These results suggest the great interest of an essential oil topical repellent in the early stages of a vector infection. The comparative study established the high value of geranium essential oil and gave future direction to the discovery of new anti-infectious solutions from monoterpenes-rich natural complexes.