Aleochara bilineata and Aleochara bipustulata are staphylinid beetles that are attracted to pitfall traps baited with dimethyl disulphide (DMDS), but the role of DMDS in their biology has not been elucidated. In still air, first instar larvae of both Aleochara species exhibited area-restricted movement when they came near to DMDS. DMDS increased the frequency of parasitism of D. radicum puparia, the preferred host, but the frequency of attacks on unpreferred piophilid puparia was not affected by DMDS. In still air, adult A. bilineata and A. bipustulata distribution was not consistently influenced by DMDS. In a Y-tube olfactometer, newly-emerged females of both species avoided DMDS-laden air; after 10 days mated females chose air with DMDS. Newly emerged males also avoided DMDS, but after 10 days mated males neither avoided nor selected DMDS-laden air: the shift in response was associated with mating status rather than age.

Aleochara bilineata and Aleochara bipustulata are staphylinid beetles that are attracted to pitfall traps baited with dimethyl disulphide (DMDS), but the role of DMDS in their biology has not been elucidated. In still air, first instar larvae of both Aleochara species exhibited area-restricted movement when they came near to DMDS. DMDS increased the frequency of parasitism of D. radicum puparia, the preferred host, but the frequency of attacks on unpreferred piophilid puparia was not affected by DMDS. In still air, adult A. bilineata and A. bipustulata distribution was not consistently influenced by DMDS. In a Y-tube olfactometer, newly-emerged females of both species avoided DMDS-laden air; after 10 days mated females chose air with DMDS. Newly emerged males also avoided DMDS, but after 10 days mated males neither avoided nor selected DMDS-laden air: the shift in response was associated with mating status rather than age.

Wax esters are substantial constituents of natural waxes, which can be found in many living organisms. Properties of lipids, including wax esters, may be significantly influenced by the position of double bond. In this diploma thesis the location of double bonds was determined by dimethyl disulfide (DMDS) derivatization followed by detection using tandem mass spectrometry with atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI). We managed to measure the APCI and ESI MS/MS spectra of 8 different wax esters with different position of double bond. Diagnostic ions determining double bond position were identified. This method could be used in HPLC/MS analysis of wax esters, which cannot be analyzed by GC/MS. It was shown that the DMDS derivatization reaction and mass detection with APCI ionization is also suitable for locating double bonds in alkenes.

O dengue e o dengue hemorrágico são considerados como as arboviroses mais importantes do ponto de vista da saúde pública além de serem também as mais disseminadas. O greening ou huanglongbing (HLB), por sua vez, é uma doença de difícil controle e rápida disseminação que afeta seriamente a produção de citros no mundo todo. É considerada a pior doença de citros da atualidade pois não tem cura e leva ao declínio e morte das árvores em alguns anos. O DMDS é um composto sulfúrico volátil derivado de plantas e que tem despertado um crescente interesse devido a sua comprovada atividade repelente e inseticida além de ação nematicida e disinfectante do solo. Visando oferecer uma alternativa para o controle de ambas as doenças, este trabalho teve como objetivo desenvolver um método de microencapsulação por spray drying e spray congealing para o dimetil dissulfeto (DMDS), visando a redução da sua volatilidade através de uma liberação controlada para o ambiente. Dessa forma, tornar-se-ia viável sua utilização como repelente, larvicida e inseticida no combate ao vetor do dengue além da sua utilização como repelente no controle do greening nas lavouras de citrus. Tentou-se a microencapsulação através de spray congealing utilizando enxofre como microencapsulante mas não se obteve sucesso devido as características térmicas do enxofre. Foram obtidas micropartículas de DMDS microencapsulado em goma arábica através da técnica de spray drying. As micropartículas e o processo de secagem foram caracterizados com relação ao rendimento de secagem, rendimento de microencapsulação, morfologia, teor de água residual, atividade de água, densidades aparente e compactada e propriedades de fluxo. Confirmou-se a possibilidade de microencapsulação de DMDS por spray drying e eficiência da goma arábica na retenção do mesmo. As partículas obtidas apresentaram boas propriedades de atividade de água, teor de água residual e densidade mas propriedades de fluxo que requerem melhoria. Foi feito também um estudo simplificado da viabilidade técnico-econômica da implantação de uma unidade de produção de DMDS microencapsulado. Esse estudo foi baseado no processo de microencapsulação estudado. Foram analisados diversos parâmetros econômicos e através destas análises verificou-se que a produção de DMDS microencapsulado pelo método utilizado seria economicamente viável. / Dengue fever and dengue hemorrhagic fever are not only considered the most important arboviruses from public health standpoint but also the most disseminated ones. Greening or huanglongbing (HLB) is a citrus disease of difficult control and fast dissemination that affects citrus production all over the world. It is considered the worst citrus disease nowadays since it does not have a cure and it causes the decline and death of the trees in a few years. Dimethyl disulfide is a volatile sulphur compound derived from plants and that has aroused growing interest due to its proved repellence and insecticidal activity, soil disinfection and nematocidal properties. Therefore, this work aimed at developing a DMDS microencapsulation method via spray drying and spray congealing in order to decrease DMDS\' volatility through a controlled release to the environment and offer a control alternative to both diseases. This would make DMDS use as a repellent, larvicide and insecticide of dengue fever\'s vector and also its use in greening control as a repellent viable. We tried to microencapsulate the DMDS through spray congealing using sulfur as a microenpsulating agent but it was unsuccessful due to the thermal characteristics of sulfur. DMDS was microencapsulated in Arabic gum through spray drying. Drying yield, microencapsulation yield, morphology of the particles, residual water percentage, water activity, bulk and tapped density and flow properties were used to characterize the microparticles and the drying process. Feasibility of DMDS microencapsulation and Arabic gum efficiency in DMDS retention were confirmed. The microparticles presented good bulk and tapped density, residual water percentage and water activity properties though its flow properties requiring further improvement. A simplified technical-economical evaluation of a DMDS microencapsulation factory was also done. This evaluation was based on the studied microencapsulation process. Many economical parameters were analysed and those analyses showed that DMDS microparticles production using the studied method would be economically viable.

O dengue e o dengue hemorrágico são considerados como as arboviroses mais importantes do ponto de vista da saúde pública além de serem também as mais disseminadas. O greening ou huanglongbing (HLB), por sua vez, é uma doença de difícil controle e rápida disseminação que afeta seriamente a produção de citros no mundo todo. É considerada a pior doença de citros da atualidade pois não tem cura e leva ao declínio e morte das árvores em alguns anos. O DMDS é um composto sulfúrico volátil derivado de plantas e que tem despertado um crescente interesse devido a sua comprovada atividade repelente e inseticida além de ação nematicida e disinfectante do solo. Visando oferecer uma alternativa para o controle de ambas as doenças, este trabalho teve como objetivo desenvolver um método de microencapsulação por spray drying e spray congealing para o dimetil dissulfeto (DMDS), visando a redução da sua volatilidade através de uma liberação controlada para o ambiente. Dessa forma, tornar-se-ia viável sua utilização como repelente, larvicida e inseticida no combate ao vetor do dengue além da sua utilização como repelente no controle do greening nas lavouras de citrus. Tentou-se a microencapsulação através de spray congealing utilizando enxofre como microencapsulante mas não se obteve sucesso devido as características térmicas do enxofre. Foram obtidas micropartículas de DMDS microencapsulado em goma arábica através da técnica de spray drying. As micropartículas e o processo de secagem foram caracterizados com relação ao rendimento de secagem, rendimento de microencapsulação, morfologia, teor de água residual, atividade de água, densidades aparente e compactada e propriedades de fluxo. Confirmou-se a possibilidade de microencapsulação de DMDS por spray drying e eficiência da goma arábica na retenção do mesmo. As partículas obtidas apresentaram boas propriedades de atividade de água, teor de água residual e densidade mas propriedades de fluxo que requerem melhoria. Foi feito também um estudo simplificado da viabilidade técnico-econômica da implantação de uma unidade de produção de DMDS microencapsulado. Esse estudo foi baseado no processo de microencapsulação estudado. Foram analisados diversos parâmetros econômicos e através destas análises verificou-se que a produção de DMDS microencapsulado pelo método utilizado seria economicamente viável. / Dengue fever and dengue hemorrhagic fever are not only considered the most important arboviruses from public health standpoint but also the most disseminated ones. Greening or huanglongbing (HLB) is a citrus disease of difficult control and fast dissemination that affects citrus production all over the world. It is considered the worst citrus disease nowadays since it does not have a cure and it causes the decline and death of the trees in a few years. Dimethyl disulfide is a volatile sulphur compound derived from plants and that has aroused growing interest due to its proved repellence and insecticidal activity, soil disinfection and nematocidal properties. Therefore, this work aimed at developing a DMDS microencapsulation method via spray drying and spray congealing in order to decrease DMDS\' volatility through a controlled release to the environment and offer a control alternative to both diseases. This would make DMDS use as a repellent, larvicide and insecticide of dengue fever\'s vector and also its use in greening control as a repellent viable. We tried to microencapsulate the DMDS through spray congealing using sulfur as a microenpsulating agent but it was unsuccessful due to the thermal characteristics of sulfur. DMDS was microencapsulated in Arabic gum through spray drying. Drying yield, microencapsulation yield, morphology of the particles, residual water percentage, water activity, bulk and tapped density and flow properties were used to characterize the microparticles and the drying process. Feasibility of DMDS microencapsulation and Arabic gum efficiency in DMDS retention were confirmed. The microparticles presented good bulk and tapped density, residual water percentage and water activity properties though its flow properties requiring further improvement. A simplified technical-economical evaluation of a DMDS microencapsulation factory was also done. This evaluation was based on the studied microencapsulation process. Many economical parameters were analysed and those analyses showed that DMDS microparticles production using the studied method would be economically viable.

<p>Today’s wide usage of the Internet makes malicious software (malware) and botnets a big problem. While anti-virus software is commonplace today, malware is constantly evolving to remain undetected. Passively monitoring DNS traffic on a network can present a platform for detecting malware on multiple computers at a low cost and low complexity. To explore this avenue for detecting malware we decided it was necessary to design an extensible system where the framework was separate from the actual detection methods. We wanted to divide the system into three parts, one for logging, one for handling modules for detection and one for taking action against suspect traffic. The system we implemented in C collects DNS traffic and processes it with modules that are compiled separately and can be plugged in or out during runtime. Two proof of concept modules have been implemented. One based on a blacklist and one based on geolocation of requested servers. The system is complete to the point of being ready for field testing and implementation of more advanced detection modules.</p>

Today’s wide usage of the Internet makes malicious software (malware) and botnets a big problem. While anti-virus software is commonplace today, malware is constantly evolving to remain undetected. Passively monitoring DNS traffic on a network can present a platform for detecting malware on multiple computers at a low cost and low complexity. To explore this avenue for detecting malware we decided it was necessary to design an extensible system where the framework was separate from the actual detection methods. We wanted to divide the system into three parts, one for logging, one for handling modules for detection and one for taking action against suspect traffic. The system we implemented in C collects DNS traffic and processes it with modules that are compiled separately and can be plugged in or out during runtime. Two proof of concept modules have been implemented. One based on a blacklist and one based on geolocation of requested servers. The system is complete to the point of being ready for field testing and implementation of more advanced detection modules.

Cette étude a été menée en collaboration entre une équipe universitaire UBO, un organisme de recherche appliqué à la gestion de pollutions chimiques accidentelles liées au transport maritime (Cedre) et d'entreprises industrielles. La collecte de données physico-chimiques sur quatre produits est organisée autour d'une double démarche : identification des facteurs encore non pris en compte dans les protocoles de gestion d'accidents et mise au clair des grandes lois régissant des phénomènes déjà identifiés comme importants. Ainsi peuvent être présentées en toute limpidité des équations raisonnables mais simples, utilisables dans des logiciels d'aide à la décision. Dans ce cadre sont traitées les limites de solubilité, avec l'influence de la salinité et de la température. Cet ouvrage contient donc une collection de données (solubilités, tensions superficielles et interfaciales, masses volumiques, stabilité chimique, vitesses d'évaporation), mais surtout met en évidence l'importance des tensions interfaciales dans la gestion des étalements et contribue à clarifier l'influence de la salinité et de la température sur les solubilités dans les conditions marines.

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Le disulfure de diméthyle (DMDS), molécule volatile libérée par les Allium, est un fumigant prometteur en remplacement du bromure de méthyle. Par l'utilisation des techniques d'électrophysiologie (patch-clamp), de biologie moléculaire et d'imagerie calcique sur neurones d'insectes, nous avons identifié de nouvelles cibles altérées par le DMDS à une faible concentration (1 µM). Le DMDS modifie l'activité spontanée régulière des DUM neurones en des bouffées de potentiels d'action séparées par des phases de silence. Cette altération de fréquence est la conséquence d'effets sur plusieurs cibles. Nous avons montré que le DMDS décale la dépendance vis-à-vis du potentiel de l'activation et de l'inactivation du courant Na2 vers de potentiels plus négatifs, rendant la cellule plus excitable. Dans un deuxième temps nous avons mis en évidence que le DMDS induit une augmentation de la concentration en calcium intracellulaire via l'activation des canaux TRPg et une sortie de calcium des stocks intracellulaires. Cette variation de calcium module, en cloche, les courants potassium dépendants du calcium (KCa). Grâce à l'étude du mode d'action du DMDS sur DUM neurones et au développement de nouvelles techniques associant la biologie moléculaire à l'électrophysiologie, nous avons apporté de nouveaux arguments en faveur de l'existence de deux courants KCa distincts. Parallèlement, grâce à une technique d'électroencéphalographie par télémétrie sur souris, nous avons révélé que le DMDS est susceptible d'engendrer des anomalies de l'activité électroencéphalographique.