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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.
31

Diagnóstico de situação epidemiológica da Leishmaniose visceral canina em Rio Verde-GO / Epidemiological diagnosis of canine visceral leishmaniasis situation in Rio Verde, state of Goiás

Galvão, Amanda Carla Acipreste [UNESP] 29 January 2016 (has links)
Submitted by AMANDA CARLA ACIPRESTE GALVÃO null (amanda@milgran.com.br) on 2016-03-12T21:11:16Z No. of bitstreams: 1 TESE DE DOUTORADO AMANDA.pdf: 2810723 bytes, checksum: c44702fbccf1142e637672c1cbccb2dd (MD5) / Rejected by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: No campo “Versão a ser disponibilizada online imediatamente” foi informado que seria disponibilizado o texto parcial porém no campo “Data para a disponibilização do texto completo” foi informado que o prazo para disponibilização de texto completo não se aplica por se tratar de texto completo a ser disponibilizado imediatamente. Caso opte pela disponibilização do texto completo selecione no campo “Versão a ser disponibilizada online imediatamente” a opção “Texto completo”. Caso queira disponibilizar imediatamente apenas o texto parcial indique no campo “data para disponibilização do texto completo” o tempo em que apenas a versão parcial estará disponível. Esta opção é utilizada caso você tenha planos de publicar seu trabalho em periódicos científicos ou em formato de livro, por exemplo e fará com que apenas as páginas pré-textuais, introdução, considerações e referências sejam disponibilizadas. Por favor, corrija esta informação realizando uma nova submissão. on 2016-03-14T21:47:46Z (GMT) / Submitted by AMANDA CARLA ACIPRESTE GALVÃO null (amanda@milgran.com.br) on 2016-03-15T16:34:19Z No. of bitstreams: 1 TESE DE DOUTORADO AMANDA.pdf: 2810723 bytes, checksum: c44702fbccf1142e637672c1cbccb2dd (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-15T17:01:42Z (GMT) No. of bitstreams: 1 galvao_aca_dr_jabo.pdf: 2810723 bytes, checksum: c44702fbccf1142e637672c1cbccb2dd (MD5) / Made available in DSpace on 2016-03-15T17:01:42Z (GMT). No. of bitstreams: 1 galvao_aca_dr_jabo.pdf: 2810723 bytes, checksum: c44702fbccf1142e637672c1cbccb2dd (MD5) Previous issue date: 2016-01-29 / A Leishmaniose Visceral Canina (LVC) preocupa as autoridades sanitárias devido ao aumento de sua incidência nos últimos anos, aliado ao fato da situação epidemiológica da enfermidade ser desconhecida na maioria das regiões. Desta forma, o presente estudo objetou realizar o diagnóstico de situação epidemiológica da leishmaniose visceral canina (LVC) no Município de Rio Verde/GO. Para tanto, a pesquisa foi desenvolvida em bairros pré-definidos da região norte do município com a avaliação das condições das três esferas da saúde (animal, humana e ambiental) relacionadas à LVC, por meio de questionários semiestruturados com a participação dos tutores dos animais; a avaliação clínica dos cães e classificação segundo a sintomatologia; a realização do diagnóstico sorológico (ELISA, RIFI e TR DPP) e o geoprocessamento da localidade dos cães reagentes. Na avaliação das condições da saúde animal, os resultados evidenciaram superpopulação canina, especialmente aqueles animais considerados sem controle de mobilidade e sem supervisão, com trânsito livre, sem assistência médicoveterinária. Com relação à saúde humana, destacou-se o convívio íntimo entre o ser humano e o seu animal de estimação, além do agravante do desconhecimento da enfermidade pela população, de seus mecanismos de transmissão, de controle e de prevenção. Sob o olhar ambiental, observou-se problemas de infraestrutura, sendo a falta de saneamento básico a principal delas, além da presença de árvores frutíferas e animais de produção favorecendo o acúmulo de matéria orgânica, facilitando e promovendo o desenvolvimento do vetor. A classificação segundo a avaliação clínica dos cães reagentes (ELISA e RIFI) foi de 65% (13/20) assintomáticos e 35% (7/20) oligossintomáticos. Na avaliação sorológica, 10,38% (55/530) foram reagentes no ELISA, desses 36,37% (20/55) foram reagentes também na RIFI, e desses todas (17/17) as amostras foram consideradas não reagentes no TR DPP®. Os cães positivos no ELISA e RIFI estavam localizados em moradias próximas, reforçando os resultados dos testes. A população, cão e ser humano, e a região estudada apresentam características favoráveis ao desenvolvimento da LVC. Desta forma, existe a necessidade de profissionais capacitados para realizar diagnóstico preciso da enfermidade, iniciando as ações de controle e prevenção, aliado à readequação do protocolo de diagnóstico, pelas autoridades competentes, para as diferentes situações epidemiológicas. / Canine Visceral Leishmaniasis (CVL) is a concern to sanitary authorities due increase on incidence observed recently and lack of knowledge about the disease epidemiological situation in most regions. So, this study focused on to perform epidemiological diagnosis of canine visceral leishmaniasis situation in Rio Verde Municipality, state of Goiás, Brazil. For this purpose, the research was performed in pre-selected neighborhoods in the north region of the municipality embracing all three areas in health (animals, human beings and environment) related to CVL using semi-structured questionnaires to animals’ owners, clinical evaluation of animals and classification according to clinical signs, serological diagnosis (ELISA, RIFI and TR DPP) and geospatial analyses of positive dogs. ). A canine overpopulation, especially on those animals that lives free in streets, without supervision of owners and veterinaries were highlighted. In relation to human health, the close contact among humans and animals and the ignorance about this disease epidemiology, prevention and control by the population were shown. About the environmental situation, infrastructural problems, as the needs of basic sanitation, were observed. Also, fruit trees and production animals’ presence were observed, which favors organic matter accumulation and allows the vector’s development. The clinical classification of the reagents animals (ELISA and RIFI) was 65% (13/20) asymptomatic and 35% (7/20) oligosymptomatic during evaluation on CI. On serological evaluation, 10.38% (55/530) were positive on ELISA and from these animals, 36.37% (20/55) were also positive on RIFI. None of the samples were considered as positive on TR DPP®. The animals considered as positives in ELISA and RIFI were located in nearby houses agreeing with the results of serological tests. The human beings and canine populations in the studied areas have favorable characteristics for the development of CVL. So, trained professionals to perform the disease accurate diagnosis, beginning actions to control and prevention, thus a adjustment of diagnostic protocol, by authorities, to different epidemiological situation.
32

The effect of Libyan date palm pollen and flax seed on general and specific properties of testicular and breast cancer cells

Alshibani, Yasmein Omran January 2016 (has links)
Magister Scientiae (Medical Bioscience) - MSc(MBS) / There is increasing concern worldwide by researchers with regards to the assessing of safety and therapeutic consumption of the plants used in traditional medicine. Date palm pollen (DPP) and flax seed have been used traditionally to improve fertility in Libya. DPP extracts have shown several reproductive beneficial effects. In vivo, studies have revealed the ability of DPP to increase sperm concentrations, ameliorate the testicular toxicity induced by cadmium and lead, raise testosterone, as well as LH and FSH hormone levels. Flax seed phytochemical analysis showed lots of valuable components such as lignans and α linolenic acid to which were attributed its positive health effects like antitumor, antioxidant and protective effects against coronary heart diseases. Moreover, flax lignans have both estrogenic and antiestrogenic potential. This study was aimed at testing the effects of Libyan DPP and flax seed on the Sertoli (TM4) cell line and human breast adenocarcinoma (MCF - 7) cell line. Different concentrations (0.01, 0.1, 1, 10, 100 and 1000 μg/ml) of ethanolic extracts of DPP and flax seed, respectively, were used to assess the morphology of TM4 and MCF - 7 cells after 24 and 72 hours exposure. Mitochondrial dehydrogenase activity as a marker of cell viability was measured by MTT assay after 24 and 72 hours exposure. Apoptotic effects were assessed by flow cytometeric APO percentage assay. TM4 cell production of Inhibin - B hormone and GGT enzyme activity under the effects of DPP or flax seed was determined by use of ELISA kits. Transepithelial electrical resistance (TEER) assay were used to detect the effect of DPP or flax seed on TM4 cell monolayer integrity. Finally the plants potential phytoestrogenic activity was determined by use of E - SCREEN assay in MCF – 7 breast cancer cells. Higher concentrations of DPP significantly increased the activity of mitochondrial dehydrogenase enzyme of TM4 cells after 24 hours associated with increasing cell number as detected in a microphotograph. Flax seed concentrations less than 100 μg/ml reduced TM4 cell viability but there were no morphological changes visible after 24 hours. MCF - 7 cells viability was reduced after 24 and 72 hours treatment with DPP and flax seed. DPP concentrations beyond 1 μg/ml significantly raised the TEER of TM4 monolayer over 72 hours while flax seed treatments caused a significant increase only after 72 hours of exposure. TM4 cells GGT activity increased significantly after exposure to higher concentrations of DPP and all flax seed concentrations. Significant stimulatory effects of all the concentrations of DPP or flax seed on TM4 inhibin - B hormone productions have been detected. Apoptotic studies showed no significant changes. E - SCREEN assay resulted in significant reduction in MCF - 7 proliferation rate under the effect of low concentrations of DPP or flax seed. Higher concentrations of the plant extracts, however, stated to increase MCF – 7 cell proliferation, this exerts weak estrogenic activities. In conclusion, the main finding of this study is that DPP and flax seed showed stimulatory effects on TM4 cells proliferation. The resistivity of TM4 cells monolayer which reflect the integrity of blood – testis barrier (BTB) was also significantly increased as well as inhibin - B production and GGT enzyme activity. In addition DPP and flax seed respectively showed inhibitory effects on MCF - 7 cells viability. This study indicated that DPP or flax seed may enhance spermatogenesis through their stimulatory action on Sertoli cells. Moreover, both plants could reduce breast cancer cells viability. However, further investigations are required to elucidate the exact mechanisms behind these obtained findings.
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Organické materiály pro organické polem řízené tranzistory a elektrochemické transistory / Organic materials for organic field-effect transistors and electrochemical transistors

Stříteský, Stanislav January 2020 (has links)
Tato práce je zaměřena na studium vlastností organických polovodivých materiálů se zaměřením na jejich vodivost a pohyblivost nosičů náboje. Hlavním cílem této práce je objasnit vztah mezi chemickou strukturou organických polovodičů a jejich vlastnostmi. Teoretická část práce je zaměřena na základy organických polovodičů, transport náboje a přehled vlastností organických polovodivých materiálů, které vedly k jejich aplikaci v polních a elektrochemických tranzistorech. Experimentální část představuje přehled použitých materiálů, způsoby jejich přípravy a charakterizační metody. V rámci výsledkové části bylo vyvinuto nebo optimalizováno několik metod pro přípravu tenkých vrstev a následně byl studován jejich vliv na výkon organických polem řízených tranzistorů. Byly charakterizovány a diskutovány relevantní vlastnosti nových organických polovodivých materiálů se zaměřením na pohyblivost nosičů náboje. Byla charakterizována a diskutována biokompatibilita několika organických polovodičů. Elektrické vlastnosti, stabilita a biokompatibilita elektroaktivních polymerních inkoustů na bázi PEDOT:PSS byla charakterizována a diskutována s ohledem na jejich možné použití v bioelektronice. Nakonec byl zkonstruován organický bioelektronický senzor pro detekci fyziologické odpovědi kardiomyocytů na základě studovaných materiálů.
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The role of Dpp and Wingless signaling gradients in directing cell shape during Drosophila wing imaginal disc development / Die Rolle von Dpp und Wingless Signalgradienten bei der Kontrolle der Zellform während der Drosophila Flügelimaginalscheibenentwicklung

Widmann, Thomas J. 04 March 2010 (has links) (PDF)
Animal morphogenesis is largely driven by concerted changes in the shape of individual cells. However, how cell shape changes are regulated and coordinated in developing animals is not well understood. Here we show that the two perpendicular signaling gradients of the morphogens Dpp, a TGF-β homologue, and Wingless, a Wnt family member, maintain tissue homoeostasis and control cell shape changes in the developing Drosophila wing. Clones of cells lacking Dpp or Wingless signaling invaginate apically, shorten apico-basally and subsequently extrude basally without disruption of the epithelium. During early larval development, the onset of Dpp and Wingless signaling correlates with the cuboidal-to-columnar cell shape transition of wing disc cells. Gradients in apical-basal length of columnar cells correlate during late larval development with the gradients of Dpp and Wingless signaling activities. Cells receiving high levels of Dpp and Wingless signaling are most elongated and apically constricted. Low levels of Dpp and Wingless signaling correlate with a shorter and apically wider cell morphology. Dpp and Wingless signaling is cell-autonomously required for maintaining the elongated columnar cell shape of late larval wing disc cells. Overactivation of these pathways results in precocious cell elongation during early larval development. These morphogenetic responses to Dpp and Wingless require the transcription factor complexes Mad and Tcf/β-catenin, respectively, indicating that they are mediated by changes in gene expression. The morphogenetic function of Wingless is in part mediated by one of its target genes, the transcription factor Vestigial. Wingless signaling promotes an enrichment of E-cadherin at the adherens junctions, and we show that E-cadherin is required to maintain apical-basal cell length. Dpp signaling controls the subcellular distribution of the activities of the small GTPase Rho1 and the regulatory light chain of non-muscle myosin II (MRLC). Alteration of Rho1 or MRLC activity has a profound effect on apical-basal cell length. Finally, we demonstrate that a decrease in Rho1 or MRLC activity rescues the shortening of cells with compromised Dpp signaling. Our results identify cell-autonomous roles for Dpp and Wingless signaling in promoting and maintaining the elongated columnar shape of wing disc cells. Furthermore, they suggest that Dpp and Wingless signaling control cell shape by regulating the actin-MyosinII/E-cadherin network. / Morphogenese in Tieren wird in hohem Maße von konzertierten Zellformveränderungen einzelner Zellen bewirkt. Es ist jedoch noch nicht hinreichend verstanden, wie Zellformveränderungen in sich entwickelnden Tieren reguliert und koordiniert werden. Hier zeigen wir, dass die zwei zueinander senkrecht stehenden Signalgradienten der Morphogene Dpp, eines TGF-β Homologs, und Wingless, eines Mitglieds der Wnt Familie, im sich entwickelnden Drosophila-Flügel Gewebe-Homöostase aufrechterhalten und Zellformveränderungen kontrollieren. Klone von Zellen, denen Dpp oder Wingless Signalaktivität fehlt, invaginieren von ihrer apikalen Seite her, verkürzen sich in apiko-basaler Richtung und extruieren im Folgenden auf der basalen Seite des Epithels, ohne es zu zerstören. Während der frühen Larvalentwicklung korreliert das Anschalten der Dpp und Wingless Signale mit der Zellformveränderung der Flügelscheibenzellen von kuboidal zu kolumnar. Gradienten in der apiko-basalen Länge von kolumnaren Zellen korrelieren während der späten Larvalentwicklung mit den Gradienten der Dpp und Wingless Signalaktivitäten. Zellen, die hohe Werte an Dpp und Wingless Signalen empfangen, sind am meisten elongiert und apikal konstringiert. Niedrige Werte von Dpp und Wingless Signalen korrelieren mit kürzerer und apikal weiterer Zellmorphologie. Dpp und Wingless Signale werden zellautonom gebraucht für die Aufrechterhaltung der elongierten Zellform von späten larvalen Flügelscheibenzellen. Die Überaktivierung dieser Signalwege führt zu vorzeitiger Zellverlängerung während der frühen Larvalentwicklung. Diese morphogenetischen Antworten auf Dpp und Wingless benötigen die Transkriptionsfaktor-Komplexe Mad beziehungsweise Tcf/β-catenin, was darauf hindeutet, dass sie durch Änderungen in der Genexpression vermittelt werden. Die morphogenetische Funktion von Wingless wird teilweise durch eines seiner Zielgene, Vestigial, vermittelt. Wingless Signale fördern die Anreicherung von E-cadherin an den Adherensverbindungen. Wir zeigen hier, dass E-cadherin gebraucht wird, um apiko-basale Zelllänge aufrechtzuerhalten. Dpp Signale kontrollieren die subzelluläre Verteilung der Aktivitäten der kleinen GTPase Rho1 und der regulatorischen leichten Kette von nicht-muskulärem Myosin II (MRLC). Eine Änderung in der Rho1 oder MRLC Aktivität hat weitreichende Auswirkungen auf die apiko-basale Zelllänge. Schließlich zeigen wir noch, dass eine Verringerung der Rho1 oder MRLC Aktivitäten die Zellverkürzung von Dpp-Signal kompromittierten Zellen rettet. Unsere Resultate identifizieren zellautonome Rollen für Dpp und Wingless Signale in der Förderung und Aufrechterhaltung der elongierten kolumnaren Zellform von Flügelimaginalscheibenzellen. Darüber hinaus suggerieren sie, dass Dpp und Wingless Signale die Zellform durch die Regulierung des Aktin-MyosinII/E-cadherin-Netzwerks kontrollieren.
35

ATIVIDADE BIOLÓGICA DE METABÓLITOS SECUNDÁRIOS DE Buddleja brasiliensis E Artemisia verlotorum / BIOLOGICAL ACTIVITY OF SECONDARY METABOLITES from Buddleja brasiliensis AND Artemisia verlotorum

Gitzel Filho, Augusto 12 January 2011 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The present work describes the phytochemical study and biological activity evaluation of the Buddleja brasiliensis Jacq. ex. Spreng and Artemisia verlotorum Lamotte. Were isolated three compounds from Buddleja brasiliensis: verbascoside (1), β-sitosterol (54) and stigmasterol (55), and it was carried out a phytochemical screening, a study of the ability to inhibit the enzymes prolyl oligopeptidase (POP), dipeptidyl peptidase (DPP IV) and acetylcholinesterase (AChE), a study of the antimicrobial activity of the specie and the extraction of the essential oil. The fractions F4 and F12 inhibited significantly POP and AchE activity. All Buddleja brasiliensis fractions tested presented low activity of DPP IV inhibition. The phenylpropanoid verbascoside (1) demonstrated a significant and selective inhibitory activity against POP (IC50 = 1.3 mM), showed weak activity against DPP-IV (IC50 >> 150 mM) and was inactive against AChE (pMIQ 9.6). The essential oil obtained from this species has as major constituents the a-tujaplicin monoterpene (11.5%) and the diterpenoid heneicosane (14.5%). This oil was inactive against all tested enzymes. The antimicrobial activity of 1, the crude extract and fractions of Buddleja brasiliensis were tested against several fungi and bacteria. Fractions dichloromethane and ethyl acetate showed moderate activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis, Streptococcus pyogenes, while 1 showed no antimicrobial activity. The crude extract, fractions and essential oil obtained from Artemisia verlotorum were also evaluated for inhibitory activity against the POP and DPP IV, as well as against various fungi and bacteria. Dichloromethane fraction of Artemisia verlotorum showed the best antimicrobial activity, mainly against the yeast Saccharomyces cerevisiae, with an MIC of 125 μg/mL. Analysis by gas chromatography coupled with mass spectrometry of the essential oil of Artemisia verlotorum indicated as the main components santonilil acetate (37.2%) and a-cadinol (9.59%). / O presente trabalho descreve o estudo fitoquímico e a avaliação da atividade biológica das espécies Buddleja brasiliensis Jacq. ex. Spreng e Artemisia verlotorum Lamotte. De Buddleja brasiliensis foram isolados três compostos: verbascosídeo (1), β-sitosterol (54) e estigmasterol (55). Desta espécie, fez-se a prospecção fitoquímica, a avaliação da capacidade de inibição das enzimas prolil oligopeptidase (POP), dipeptidil peptidase (DPP IV) e acetilcolinesterase (AChE), a obtenção do óleo essencial, e avaliação da atividade antimicrobiana. Nos testes de inibição frente à enzima POP foi observada significativa atividade das frações F4 e F12. Estas frações também demonstraram atividade inibitória da enzima AChE. Nos testes com a DPP IV verificou-se baixa atividade para todas as frações testadas. O fenilpropanóide verbascosídeo (1) demonstrou ter uma significativa e seletiva atividade inibitória frente à POP (IC50 = 1,3 μM), enquanto frente à DPP IV demonstrou fraca atividade inibitória (IC50 >>150 μM) e frente à AChE foi inativo (pMIQ de 9,6). O óleo essencial obtido desta espécie tem como constituintes principais o monoterpeno a-tujaplicina (11,5 %) e o diterpeno heneicosano (14,5 %). Este óleo foi inativo frente a todas as enzimas testadas. A atividade antimicrobiana de 1, do extrato bruto e das frações de Buddleja brasiliensis foi testada frente a vários fungos e bactérias. O composto 1 não apresentou nenhuma atividade antimicrobiana, enquanto que as frações que demonstram atividade moderada foram as frações Diclorometano e Acetato de etila para Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis, Streptococcus pyogenes. O extrato bruto, as frações e o óleo essencial obtidos de Artemisia verlotorum também foram avaliados quanto a atividade de inibição frente à POP e a DPP IV, bem como frente a vários fungos e bactérias. A fração Diclorometano de Artemisia verlotorum demonstrou a melhor atividade antimicrobiana, principalmente frente ao fungo Saccharomyces cerevisae, com uma CIM de 125 μg/mL. A análise por cromatografia gasosa acoplada a espectrômetro de massa do óleo essencial de Artemisia verlotorum indicou como constituintes principais acetato de santonilila (37,2 %) e a-cadinol (9,59%).
36

Studies on Correlation between Microstructures and Electronic Properties of Organic Semiconductors

Mukhopadhyay, Tushita January 2017 (has links) (PDF)
The work carried out in this thesis systematically investigates the correlation between microstructures and electronic properties of organic semiconductors. The major directions that were pursued in this thesis are: (i) studies on structure-property relationship by rational design and synthesis of monodisperse oligomers with varying chain-lengths (ii) role of electronic properties and aggregation (microstructures) in governing singlet fission (SF). In the first part of the thesis, the optical, structural and charge transport properties of Diketopyrrolopyrrole (DPP)-based oligomers, as a function of the chain length, has been discussed. The energy bands became wider with an increase in chain length and a gain in backbone electron affinity was observed, with an offset in microstructural order. With an increase in chain length, the tendency to form intramolecular aggregates increased as compared to intermolecular aggregates due to the onset of backbone conformational defects and chain folding. An insight into the solid-state packing and microstructural order has been obtained by steady-state and transient spectroscopy, grazing incidence small angle x-ray scattering (GISAXS), atomic force microscopy (AFM) and transmission electron microscopy (TEM) studies. The charge-carrier mobilities varied in accordance with the degree of microstructural order as: dimer > trimer > pentamer. A library of DPP-DPP based trimers was also generated by modifying the donor chromophore (phenyl, thiophene and selenophene) in the oligomer backbone. Highest n-channel mobility of ~0.2 cm2V-1s-1 was obtained which validated that: (a) the effect of solid-state packing predominates the effect of backbone electronic structure on charge carrier mobility. Although oligomers possess lesser backbone defects than polymers in general, their charge carrier mobilities were not comparable to that of 2DPP-OD-TEG polymer, which forms highly oriented and isotropic edge-on crystallites/microstructures in the thin film, shows high n-channel mobility of 3 cm2V-1s-1 and band-like transport ;(b) although delocalized electronic states are achieved at greater chain lengths, the degree of solid-state microstructural order drastically reduces which leads to lower charge carrier mobilities; (c) conformational collapse resulted in lower electron mobilities and an increase in ambipolarity. The later part of the thesis debates on the relative contribution of electronic structure and aggregation (microstructures) in governing singlet fission (SF). Motivated by the recent SF model in carotenoid aggregates, a DPP-DPP based oligomer was synthesized by incorporating a vinylene bridge to imbue “polyene” character in the chromophore. Transient Spectroscopy (TA) measurements were carried out to monitor the formation of triplet states in the oligomer and to probe the occurrence of singlet fission. Although the oligomer exhibits “polyene” character like a typical “carotenoid aggregate”, it did not show singlet fission because of the additional stabilization of the singlet (S1) state which reduces the ∆EST. This study rationalized the importance of judicious control of band structures as well as microstructures to observe the SF phenomenon in this category of chromophores. The novel synthetic protocol provides the scope to tailor DPP-DPP based materials with desired effective conjugation lengths and side chains and can foreshow great prospects for future generation of organic electronics.
37

ISOLAMENTO E ATIVIDADE FARMACOLÓGICA DE METABÓLITOS SECUNDÁRIOS DE PLANTAS DA MEDICINA POPULAR DO RIO GRANDE DO SUL / ISOLATION AND PHARMACOLOGIC ACTIVITY OF SECONDARY METABOLITS OF PLANTS OF THE POPULAR MEDICINE OF THE RIO GRANDE DO SUL

Marques, Micaela Rossato 21 January 2009 (has links)
The present work describes the phytochemistry study and of biological activity of the species Scutellaria racemosa Pers (Labiatae) and Pfaffia tuberosa Spreng (Amaranthaceae). Four compounds were isolated of the S. racemosa Pers: lupeol (14), oroxilin A (10), dinatin (12) and oroxyloside (11). The antimicrobial and cytotoxic activities and the capacity of inhibition of enzymes prolyl oligopeptidase (POP), dipeptidyl peptidase IV (DPP IV) and acetylcholinesterase (AChE) of the crude extract (EB), fractions and isolated compounds of the S. racemosa Pers were evaluated. The n-hexane (FH) and ethyl acetate (FA) fractions were the most active against Staphylococcus epidermidis, Bacillus subtilis and Pseudomonas aeruginosa. The evaluation of the crude extract and fractions using the Brine Shrimp Lethality Test indicated that this plant does not present toxicity. About the tests of enzymatic inhibition, the ethyl acetate (FA) and n-butanol (FB) fractions of S. racemosa Pers and the compounds dinatin (12) and oroxyloside (11) demonstrated significant capacity of inhibition of the POP. The inhibition promoted for the dinatina (12) (100 μM) corresponded 43% and for the oroxyloside (11) (100 μM) corresponded 34% of the total enzyme tested. The crude extract (EB) and the respective fractions of the Pfaffia tuberosa Spreng were also evaluated about the antimicrobial and cytotoxic activities and of enzymatic inhibition of the POP, DPP IV and AChE. Through these assays, it was verified that the crude extract (EB) and the fractions of the Pfaffia tuberosa Spreng do not present important antimicrobial and cytotoxic activity. In relation to the tests of inibitory activity of the POP, the dichloromethane (FD) and ethyl acetate (FA) fractions present IC50 of 21.4 and 28.5 μg/mL against of POP, respectively. Dichloromethane, ethyl acetate and n-butanol fractions (FD, FA and FB) presented low activity against DPP IV (< 20%). The ethyl acetate (FA) and n-butanol (FB) fractions showed significant inhibition of the AChE in the amounts, 6.25 and 25 μg, respectively. / O presente trabalho descreve o estudo fitoquímico e a atividade biológica das espécies Scutellaria racemosa Pers (Labiatae) e Pfaffia tuberosa Spreng (Amaranthaceae). Quatro compostos foram isolados da S. racemosa Pers: lupeol (14), oroxilina A (10), dinatina (12) e oroxilosídeo (11). A atividade antimicrobiana, citotóxica e a capacidade de inibição das enzimas prolil oligopeptidase (POP), dipeptidil peptidase IV (DPP IV) e acetilcolinesterase (AChE) do extrato bruto (EB), frações e compostos isolados da S. racemosa Pers foram avaliadas. As frações n-hexano (FH) e acetato de etila (FA) foram as mais ativas contra Staphylococcus epidermidis, Bacillus subtilis e Pseudomonas aeruginosa. A avaliação do extrato bruto (EB) e frações através do teste de letalidade frente a Artemia salina indicou que esta planta não apresenta toxicidade significativa. Quanto aos testes de inibição enzimática, as frações acetato de etila (FA) e n-butanol (FB) de S. racemosa Pers e os compostos dinatina (12) e oroxilosídeo (11) demonstraram significativa capacidade de inibição da POP. A inibição promovida pela dinatina (12) (100 μM) correspondeu a 43% e pelo oroxilosídeo (11) (100 μM) correspondeu a 34% do total de enzima testada. O extrato bruto (EB) e as respectivas frações da Pfaffia tuberosa Spreng também foram avaliadas quanto a atividade antimicrobiana, citotóxica e de inibição enzimática da POP, DPP IV e AChE. Através destes ensaios, verificou-se que o extrato bruto (EB) e a frações da Pfaffia tuberosa Spreng não apresentam importante atividade antimicrobiana e citotóxica. Em relação aos testes de atividade inibitória da POP, as frações diclorometano (FD) e acetato de etila (FA) foram as que apresentaram os melhores resultados, com IC50 de 21,4 e 28,5 μg/mL, respectivamente. As frações diclorometano, acetato de etila e n-butanol (FD, FA e FB) apresentaram baixa capacidade de inibição da DPP IV (< 20%). As frações acetato de etila (FA) e n-butanol (FB) apresentaram significativa inibição da AChE, nas quantidades de 6,25 e 25 μg, respectivamente.
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The role of Dpp and Wingless signaling gradients in directing cell shape during Drosophila wing imaginal disc development

Widmann, Thomas J. 21 December 2009 (has links)
Animal morphogenesis is largely driven by concerted changes in the shape of individual cells. However, how cell shape changes are regulated and coordinated in developing animals is not well understood. Here we show that the two perpendicular signaling gradients of the morphogens Dpp, a TGF-β homologue, and Wingless, a Wnt family member, maintain tissue homoeostasis and control cell shape changes in the developing Drosophila wing. Clones of cells lacking Dpp or Wingless signaling invaginate apically, shorten apico-basally and subsequently extrude basally without disruption of the epithelium. During early larval development, the onset of Dpp and Wingless signaling correlates with the cuboidal-to-columnar cell shape transition of wing disc cells. Gradients in apical-basal length of columnar cells correlate during late larval development with the gradients of Dpp and Wingless signaling activities. Cells receiving high levels of Dpp and Wingless signaling are most elongated and apically constricted. Low levels of Dpp and Wingless signaling correlate with a shorter and apically wider cell morphology. Dpp and Wingless signaling is cell-autonomously required for maintaining the elongated columnar cell shape of late larval wing disc cells. Overactivation of these pathways results in precocious cell elongation during early larval development. These morphogenetic responses to Dpp and Wingless require the transcription factor complexes Mad and Tcf/β-catenin, respectively, indicating that they are mediated by changes in gene expression. The morphogenetic function of Wingless is in part mediated by one of its target genes, the transcription factor Vestigial. Wingless signaling promotes an enrichment of E-cadherin at the adherens junctions, and we show that E-cadherin is required to maintain apical-basal cell length. Dpp signaling controls the subcellular distribution of the activities of the small GTPase Rho1 and the regulatory light chain of non-muscle myosin II (MRLC). Alteration of Rho1 or MRLC activity has a profound effect on apical-basal cell length. Finally, we demonstrate that a decrease in Rho1 or MRLC activity rescues the shortening of cells with compromised Dpp signaling. Our results identify cell-autonomous roles for Dpp and Wingless signaling in promoting and maintaining the elongated columnar shape of wing disc cells. Furthermore, they suggest that Dpp and Wingless signaling control cell shape by regulating the actin-MyosinII/E-cadherin network. / Morphogenese in Tieren wird in hohem Maße von konzertierten Zellformveränderungen einzelner Zellen bewirkt. Es ist jedoch noch nicht hinreichend verstanden, wie Zellformveränderungen in sich entwickelnden Tieren reguliert und koordiniert werden. Hier zeigen wir, dass die zwei zueinander senkrecht stehenden Signalgradienten der Morphogene Dpp, eines TGF-β Homologs, und Wingless, eines Mitglieds der Wnt Familie, im sich entwickelnden Drosophila-Flügel Gewebe-Homöostase aufrechterhalten und Zellformveränderungen kontrollieren. Klone von Zellen, denen Dpp oder Wingless Signalaktivität fehlt, invaginieren von ihrer apikalen Seite her, verkürzen sich in apiko-basaler Richtung und extruieren im Folgenden auf der basalen Seite des Epithels, ohne es zu zerstören. Während der frühen Larvalentwicklung korreliert das Anschalten der Dpp und Wingless Signale mit der Zellformveränderung der Flügelscheibenzellen von kuboidal zu kolumnar. Gradienten in der apiko-basalen Länge von kolumnaren Zellen korrelieren während der späten Larvalentwicklung mit den Gradienten der Dpp und Wingless Signalaktivitäten. Zellen, die hohe Werte an Dpp und Wingless Signalen empfangen, sind am meisten elongiert und apikal konstringiert. Niedrige Werte von Dpp und Wingless Signalen korrelieren mit kürzerer und apikal weiterer Zellmorphologie. Dpp und Wingless Signale werden zellautonom gebraucht für die Aufrechterhaltung der elongierten Zellform von späten larvalen Flügelscheibenzellen. Die Überaktivierung dieser Signalwege führt zu vorzeitiger Zellverlängerung während der frühen Larvalentwicklung. Diese morphogenetischen Antworten auf Dpp und Wingless benötigen die Transkriptionsfaktor-Komplexe Mad beziehungsweise Tcf/β-catenin, was darauf hindeutet, dass sie durch Änderungen in der Genexpression vermittelt werden. Die morphogenetische Funktion von Wingless wird teilweise durch eines seiner Zielgene, Vestigial, vermittelt. Wingless Signale fördern die Anreicherung von E-cadherin an den Adherensverbindungen. Wir zeigen hier, dass E-cadherin gebraucht wird, um apiko-basale Zelllänge aufrechtzuerhalten. Dpp Signale kontrollieren die subzelluläre Verteilung der Aktivitäten der kleinen GTPase Rho1 und der regulatorischen leichten Kette von nicht-muskulärem Myosin II (MRLC). Eine Änderung in der Rho1 oder MRLC Aktivität hat weitreichende Auswirkungen auf die apiko-basale Zelllänge. Schließlich zeigen wir noch, dass eine Verringerung der Rho1 oder MRLC Aktivitäten die Zellverkürzung von Dpp-Signal kompromittierten Zellen rettet. Unsere Resultate identifizieren zellautonome Rollen für Dpp und Wingless Signale in der Förderung und Aufrechterhaltung der elongierten kolumnaren Zellform von Flügelimaginalscheibenzellen. Darüber hinaus suggerieren sie, dass Dpp und Wingless Signale die Zellform durch die Regulierung des Aktin-MyosinII/E-cadherin-Netzwerks kontrollieren.
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Self-organized Growth in Developing Epithelia

Mumcu, Peer 19 October 2011 (has links)
The development of a multicellular organism, such as a human or an animal, begins with the fertilization of an egg cell. Thereupon the organism grows by repeated cell divisions until the adult size is reached and growth stops. Although it is known that intrinsic mechanisms determine the final size of developing organs and organisms, the basic principles of growth control are still poorly understood. However, there is strong evidence that certain morphogens, which are a special class of signaling molecules, act as growth factors and play a key role in growth control. In this work, growth control is studied from a mainly theoretical viewpoint. A discrete vertex model describing the organization of cells by a network of polygons is used, including a description of the cell cycle and a description of dynamical morphogen distributions. Self-organized growth is studied by introducing growth rules that govern cell divisions based on the local morphogen level. This discrete description is complemented by a continuum theory to gain further insight into the dynamics of self-organized growth processes. The theoretical description is applied to the developing wing of the fruit fly Drosophila melanogaster. In the developing wing, which is an epithelium consisting of single-layered cell sheets, the morphogen Decapentaplegic (Dpp) acts as a key growth factor. Experimental data shows that the Dpp distribution is dynamic and adapts to the size of the developing wing. Two mechanisms that rely on a regulatory molecule species and lead to such a dynamic behaviour of the Dpp distribution are studied. Several growth rules are tested and the resulting growth behaviour is quantitatively compared to experimental data of the developing wing. A particular growth rule, that triggers a cell division when the local morphogen level has increased by a certain relative amount, is found to be consistent with experimental observations under normal and several perturbed conditions. It is shown that mechanical stresses that arise due to spatial growth inhomogeneities can have a stabilizing effect on the growth process.
40

Morphogenetic signaling in growing tissues

Bittig, Thomas 23 September 2008 (has links)
During the development of multicellular organisms, organs grow to well-defined shapes and sizes. The proper size and patterning of tissues are ensured by signaling molecules as e.g. morphogens. Secreted from a restricted source, morphogens spread into the adjacent target tissue where they form a graded concentration profile. Upon binding of the morphogens to receptors on the cell surfaces, the morphogenetic signal is transduced inside the cell via the phosphorylation of transcription factors, which subsequently regulate the expression of different target genes. Thus, cell fates are determined by the local concentration of such morphogens. In this work, we investigate three key aspects of morphogenetic signaling processes in growing tissues. First, we study the mechanics of tissue growth via cell division and cell death. We examine the rearrangements of cells on large scales and times by developing a continuum theory which describes the growing tissue as an active complex fluid. In our description we include anisotropic stresses generated by oriented cell division, and we show that average cellular trajectories exhibit anisotropic scaling behaviors. Our description is used to study experimentally measured shape changes of the developing wing disk of the fruit fly Drosophila melanogaster. Second, we focus on the spreading of morphogens in growing tissues. We show that the flow field of cell movements due to oriented cell division and cell death causes a drift term in the morphogen transport equation, which captures the stretching and dilution of the concentration profile. Comparing our theoretical results to recent experiments in the Drosophila wing disk, we find that the transport of the morphogen Dpp is mainly intracellular. We moreover show that the decay length of the Dpp gradient increases during development as a result of changing degradation rate and diffusion coefficient, whereas the drift of molecules due to growth is negligible. Thus growth does not affect the decay length of the gradient, but the decay length of the gradient might affect the tissue growth rate as discussed in this work. Finally, we develop a microscopic theoretical description of the intracellular transduction machinery of morphogenetic signals within an individual cell. Our description captures the kinetics of the trafficking of proteins between different cellular compartments in response to receptor-bound signaling molecules. Analyzing experimental data at the Drosophila neuromuscular junction, we show that the morphogenetic signaling is modulated by synaptic signaling via neuronal action potentials.

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