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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Sistema imune em aracnídeos: estrutura química e atividade biológica de peptídeos antimicrobianos da hemolinfa da aranha Acanthoscurria gomesiana. / Immune system in aracnids: chemical structure and biological activity of antimicrobials peptides from Acanthoscurria gomesiana.

Silva Junior, Pedro Ismael da 22 September 2000 (has links)
Peptídeos antimicrobianos são importantes componentes do sistema imune de vertebrados e invertebrados. Neste trabalho purificamos e caracterizamos quatro moléculas presentes na hemolinfa da aranha Acanthoscurria gomesiana: 1) theraphosinina, peptídeo de 4052,5 Da purificado do plasma, apresenta atividade anti-Micrococcus luteus e não apresenta similaridade com outros peptídeos. A partir dos hemócitos foram purificados: 2) mygalomorphina, um peptídeo de 415,9 Da com atividade anti-Escherichia coli. Sua atividade está relacionada à produção de H2O2 pois é inibida por catalase; 3) gomesina, um peptídeo de 2270,4 Da que apresenta alta similaridade com taquiplesinas e protegrinas. Apresenta amplo espectro de atividade contra bactérias, leveduras, fungos e Leishmania; 4) acanthoscurrina, um peptídeo rico em glicina, que apresenta duas isoformas com 10132,4 e 10249,1Da. Este peptídeo tem atividade contra E. coli e Candida albicans e apresenta grande similaridade com proteinas antifúngicas de insetos e também com proteínas relacionadas com a defesa em plantas. / Antimicrobial peptides are important components of the vertebrates and invertebrates immune system. In this work we purified and characterized four molecules from Acanthoscurria gomesiana spider hemolimph: 1) theraphosinin, a 4,052.5 Da peptide purified from plasma with anti-Micrococcus luteus activity. It does not show similarity with any other invertebrate immune peptides. From the hemocytes three peptides have been purified: 2) mygalomorphin, a peptide with 415.9 Da, which shows anti-Escherichia coli activity. This activity is inhibited by catalase, therefore it may be, related to the H2O2 production; 3) gomesin, a peptide with 2,270.4 Da, that shows high similarity with tachyplesins and protegrins. It have large activity spectrum against bacteria, yeast, fungi and Leishmania; 4) acanthoscurrin, a glycine-rich peptide that shows two isoforms of 10,132.4 and 10,249.1 Da. This peptide has activity against E. coli and Candida albicans and shows high similarity with antifungal proteins of insects and plants defense proteins.
282

american folk

Poe, Preston 29 November 2004 (has links)
This piece is a forty-five minute video utilizing the concept of liquid medium cross-pollination of media including, sound, music, video and "found" art. The piece was shot over the course of three years at a cost of twelve thousand dollars using a Sony trv950, a Mac PowerBook, a 1954 Gibson J45, and a 1971 Guild F212, edited on Final Cut Pro and conceptualized for multiple viewings.
283

A Domain Based Approach to Crawl the Hidden Web

Pandya, Milan 04 December 2006 (has links)
There is a lot of research work being performed on indexing the Web. More and more sophisticated Web crawlers are been designed to search and index the Web faster. But all these traditional crawlers crawl only the part of Web we call “Surface Web”. They are unable to crawl the hidden portion of the Web. These traditional crawlers retrieve contents only from surface Web pages which are just a set of Web pages linked by some hyperlinks and ignoring the hidden information. Hence, they ignore tremendous amount of information hidden behind these search forms in Web pages. Most of the published research has been done to detect such searchable forms and make a systematic search over these forms. Our approach here will be based on a Web crawler that analyzes search forms and fills tem with appropriate content to retrieve maximum relevant information from the database.
284

A Distributed Approach to Crawl Domain Specific Hidden Web

Desai, Lovekeshkumar 03 August 2007 (has links)
A large amount of on-line information resides on the invisible web - web pages generated dynamically from databases and other data sources hidden from current crawlers which retrieve content only from the publicly indexable Web. Specially, they ignore the tremendous amount of high quality content "hidden" behind search forms, and pages that require authorization or prior registration in large searchable electronic databases. To extracting data from the hidden web, it is necessary to find the search forms and fill them with appropriate information to retrieve maximum relevant information. To fulfill the complex challenges that arise when attempting to search hidden web i.e. lots of analysis of search forms as well as retrieved information also, it becomes eminent to design and implement a distributed web crawler that runs on a network of workstations to extract data from hidden web. We describe the software architecture of the distributed and scalable system and also present a number of novel techniques that went into its design and implementation to extract maximum relevant data from hidden web for achieving high performance.
285

Olfactory sensitivity of spider monkeys (Ateles geoffroyi) for "green odors"

Løtvedt, Pia Katrine January 2011 (has links)
Primates have traditionally been viewed as having a poorly developed sense of smell. However, in recent years, studies have shown that at least some primate species use olfaction in a number of behaviors, and that they have a high olfactory sensitivity for various chemical classes of odorants. Using a two-choice instrumental conditioning paradigm, the present study assessed olfactor ydetection thresholds of three spider monkeys (Ateles geoffroyi) for eight aliphatic alcohols and aldehydes, known as "green odors". With all odorants, the animals detected concentrations below 1 parts per million, with single individuals performing even better. The type of functional group present systematically affected olfactory detection thresholds, whereas the presence, position and configuration of a double bond did not. Compared to previously tested classes of odorants, thespider monkeys were not particularly sensitive to "green odors". Furthermore, they are lesssensitive for "green odors" compared to humans and mice. The present results suggest that neuroanatomical and genetic comparisons across species are poor predictors of olfactory sensitivity.
286

Recombinant spider silk with antimicrobial properties

Nilebäck, Linnea January 2013 (has links)
Immobilizing antimicrobial substances onto biocompatible materials is an important approach for the design of novel, functionalized medical devices. By choosing antimicrobial substances from innate immune systems, the risk for development of resistance in pathogenic microbes is lower than if conventional antibiotics are used. Combining natural antimicrobial peptides and bactericidal enzymes with strong and elastic spider silk through recombinant protein technology would enable large-scale production of materials that could serve as functionalized wound dressings. Herein, fusion proteins with the engineered spider silk sequence 4RepCT and five different antimicrobial substances were constructed using two different strategies. In the first, the fusion proteins had a His-tag as well as a solubility-enhancing domain N-terminally to the antimicrobial agent during expression. The tags were cleaved and separated from the target protein during the purification process. The other approach provided a His-tag but no additional solubility domain. The antimicrobial agents included in the work were a charge engineered enzyme and four antimicrobial peptides herein called Peptide A, Peptide B, Peptide C and Peptide D. Four out of five fusion proteins could be expressed in Escherichia coli without exhibiting noticeable toxicity to the host. However, most target proteins were found in the non-soluble fraction. For D-4RepCT, neither soluble nor non-soluble proteins were identified. An operating strategy for expression and purification of antimicrobial spider silk proteins was developed, where the construct system providing the solubility-enhancing domain N-terminally to the antimicrobial sequence, and long time expression at low temperatures is a promising approach. The fusion proteins A-4RepCT and C-4RepCT could be produced in adequate amounts, and they proved to possess the ability to assemble into stable fibers. When incubating solutions of Escherichia coli on the functionalized silk material A-4RepCT, it showed to decrease the number of living bacteria in solution, in contrary to wild-type 4RepCT on which bacteria continued to proliferate. Initial studies of the viability of bacteria adhered to the surface of the functionalized spider silk are so far inconclusive. A larger sample size, complementary experiments and methodology optimization is needed for a proper assessment of antibacterial properties. However, preliminary results for the development of antimicrobial spider silk are positive, and the approach elaborated in this work is believed to be applicable for the construction of functional spider silk with a wide range of natural antimicrobial agents for future wound healing applications.
287

Análise do transcriptoma da glândula produtora de veneno de Loxosceles intermedia (aranha marrom): perfil de expressão e identificação de novas toxinas / Effects of metalloproteinas from Brotrops leucurus venon and brown spiders venoms on endothelial cell and components of extracellular matrix

Gremski, Luiza Helena [UNIFESP] 28 July 2010 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:49:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Aranhas do gênero Loxosceles, são responsáveis por acidentes em todo o mundo, com grande importância clínica no Sul do Brasil. Os venenos destas aranhas são compostos por diversas toxinas, entre elas proteínas, responsáveis pelo quadro conhecido como loxoscelismo. No intuito de descrever o perfil transcricional da glândula produtora de veneno da aranha Loxosceles intermedia geramos uma biblioteca de cDNA bastante ampla e seus transcritos foram funcionalmente caracterizados. Após o processamento inicial das sequências, 1.843 ESTs (Expressed Sequence Tags) apresentavam qualidade suficiente para as análises posteriores. Estas sequências foram montadas em 538 clusters, sendo que 281 eram singletons. Após análises de similaridade, mais de 50% das ESTs demonstraram algum grau de semelhança com proteínas conhecidas. As análises de similaridade também demonstraram que os transcritos que codificavam para toxinas, perfaziam 43% de todas as sequências e abrangem uma parte significativa das ESTs. As toxinas mais frequentes foram anotadas como pertencentes à família LiTx de toxinas inseticidas. As fosfolipases-D e as metaloproteases semelhantes à astacinas perfazem, cada uma, cerca de 9% do total de transcritos. Componentes tóxicos tais como inibidores de serino-proteases, hialuronidase e proteínas alergênicas foram também identificadas, porém com menor representação. Quase 10% das ESTs codificam para proteínas envolvidas em processos celulares. O presente trabalho descreve também as etapas para clonagem, expressão heteróloga e purificação de um transcrito semelhante a um inibidor de serino-protease, identificado na biblioteca de cDNA. É sabido que proteínas desta família apresentam um grande potencial de aplicação como drogas antitrombóticas, atuando como agentes terapêuticos que influenciam a atividade de fatores de coagulação. Esses dados fornecem uma visão global do perfil de expressão da glândula de veneno de L. intermedia, revelam diferenças significantes entre venenos de aranhas do gênero Loxosceles e descrevem a produção de uma nova toxina recombinante. / Loxosceles genus spiders are responsible for accidents all over the world and have clinical importance in the South of Brazil. The venom of these spiders is made up of several toxins, including proteins, which are responsible for the clinical pattern called loxoscelism. To describe the transcriptional profile of the L. intermedia venom gland, we generated a wide cDNA library, and its transcripts were functionally and structurally analyzed. After initial analyses, 1,843 ESTs produced readable sequences that were grouped into 538 clusters, 281 of which were singletons. Nine hundred eighty-five reads (53% of total ESTs) matched to known proteins. Similarity searches showed that toxinencoding transcripts totalize 43% of the total library and comprise a great number of ESTs. The most frequent toxins were from the LiTx family, which are known for their insecticidal activity. Both phospholipase-D and astacin-like metalloproteases toxins account for approximately 9% of total transcripts. Toxins components such as serine proteases, hyaluronidases and venom allergens were also found but with minor representation. Almost 10% of the ESTs encode for proteins involved in cellular processes. This work also describes the stages for cloning, heterologous expression and purification of a cDNA similar to a protease inhibitor identified in the cDNA library. It is known that proteins belonging to this family have an application potential as antithrombotic drugs, acting as therapeutic agents that influences the activity of coagulation factors. These data provide an important overview of the L. intermedia venom gland expression scenario, revealed significant differences from profiles of other spiders from the Loxosceles genus and describe the production of a novel recombinant toxin. / TEDE / BV UNIFESP: Teses e dissertações
288

Estrutura genética populacional de Aglaoctenus lagotis (Aranneae, Lycosidae) em fragmentos de Mata Atlântica / Genetic population structure of Aglaoctenus lagotis (Aranneae, Lycosidae) in Brazilian Atlantic rainforest remnants

Macrini, Camila Menezes Trindade, 1981- 02 October 2013 (has links)
Orientador: Vera Nisaka Solferini / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T12:04:17Z (GMT). No. of bitstreams: 1 Macrini_CamilaMenezesTrindade_D.pdf: 8857853 bytes, checksum: 881e366a70a23fe7a69154f9b30021f3 (MD5) Previous issue date: 2012 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Doutorado / Genetica Animal e Evolução / Mestra em Genética e Biologia Molecular
289

Client-side threats and a honeyclient-based defense mechanism, Honeyscout

Clementson, Christian January 2009 (has links)
Client-side computers connected to the Internet today are exposed to a lot malicious activity. Browsing the web can easily result in malware infection even if the user only visits well known and trusted sites. Attackers use website vulnerabilities and ad-networks to expose their malicious code to a large user base. The continuing trend of the attackers seems to be botnet construction that collects large amounts of data which could be a serious threat to company secrets and personal integrity. Meanwhile security researches are using a technology known as honeypots/honeyclients to find and analyze new malware. This thesis takes the concept of honeyclients and combines it with a proxy and database software to construct a new kind of real time defense mechanism usable in live environments. The concept is given the name Honeyscout and it analyzes any content before it reaches the user by using visited sites as a starting point for further crawling, blacklisting any malicious content found. A proof-of-concept honeyscout has been developed using the honeyclient Monkey-Spider by Ali Ikinci as a base. Results from the evaluation shows that the concept has potential as an effective and user-friendly defense technology. There are however large needs to further optimize and speed up the crawling process.
290

Impact of cover cropping on arthropods in corn on the western high plains

Davis, Holly N. January 1900 (has links)
Master of Science / Department of Entomology / Larry L. Buschman, Lawrent Buschman / This study evaluated whether using a cover crop with corn would increase the threat from spider mites in western Kansas because cover crops may serve as a winter host. This study also evaluated whether a cover crop could affect corn rootworm and other ground dwelling arthropods in the cornfield. In the first study, downy brome, Bromus tectorum L., was used as the winter cover crop. There were two trials repeated for three years each. Each trial included: two amounts of irrigation, downy brome, and herbicide to control weeds. In the first trial there were no significant differences in corn rootworm, Diabrotica virgifera LeConte, damage across treatments, because there were no differences in brome residue across the treatments. In the second trial, corn rootworm damage was significantly more in plots with higher amounts of downy brome residue. There were no differences in numbers of spider mites: Banks grass mites, Oligonychus pratensis (Banks) or twospotted spider mites, Tetranychus urticae Koch, across treatments. Spider mite populations appeared to be suppressed by the predatory mite Neoseiulus spp., which also overwintered in the cover crop. Corn rootworm samples taken from a no-till irrigation experiment were variable among irrigation treatments but indicated a trend for rootworm damage to increase with increasing irrigation. In the second study, winter wheat, Triticum aestivum L., was used as the winter cover crop. There were three trials repeated for three years each. Each trial included two amounts of irrigation and winter wheat and three amounts of herbicide to control weeds. Upon completion of the agronomy trials, the plots were split into two subplots and one was tilled. Pitfall traps were installed to capture ground dwelling arthropods: (Coleoptera: Carabidae), wolf spiders (Araneae: Lycosidae) and crickets (Orthoptera: Gryllidae). Four carabid genera were more common under no-till conditions. One was more common in tilled plots. Five carabid genera were more common in plots with a history of high weed densities. Two carabid genera were more numerous in plots with the history of a cover crop. Crickets were more common under no-till conditions. Wolf spiders were more common in no tillage with a history of a cover crop.

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