Síntese, caracterização e estudo da atividade fungicida e antitumoral de novas dialquilfosfonilacilidrazonas.

O trabalho apresentado refere-se a síntese de dialquilfosfonilacilidrazonas inéditas que ocorreu em 3 etapas: a primeira etapa consistiu na síntese de diferentes fosfonoacetatos de dialquila obtidos por meio da reação do bromoacetato de etila com o fosfito de trialquila de interesse. A segunda etapa foi a síntese da dietoxifosfonilidrazida acética formada por meio da reação dos fosfonoacetatos de dialquila sintetizados com a hidrazina. A terceira e última etapa consistiu na condensação das dietoxifosfonilidrazidas acética com diferentes aldeídos heterocíclicos. Os compostos obtidos, nomeados de um até 17, foram caracterizados por RMN de H1 e C13 e P31, infravermelho (IV) e espectroscopia de massas (EM). Foram obtidos 17 compostos inéditos com mistura diastereoisomérica, de conformação preferencial E. A atividade fungicida de cada molécula sintetizada foi realizada por meio do teste de sensibilidade in vitro em relação aos fitopatógenos fúngicos Pilidium sp., Alternaria sp., Penicilium sp. e Colletotrichum gloeosporioides, responsáveis por doenças de importância econômica na pós-colheita de frutos. No entanto, nenhum dos compostou apresentou a atividade fungicida esperada para os fungos avaliados. Os compostos ainda foram testados em células de melanoma murino da linhagem B16F10, com objetivo de verificar a atividade biológica no crescimento tumoral de células de melanoma. De todos os compostos testados os compostos 2 e 13 apresentaram atividade biológica, ainda que relativamente baixa. Após a síntese e a purificação dos compostos sintetizados, foi verificada a atividade dos mesmos frente a enzima acetilcolinesterase, usada como indicador de toxicidade de compostos organofosforados. O ensaio de inibição da enzima AChE revelou que o composto 2 não inibe a enzima, juntamente com os compostos 3, 7, 8 e 16 enquanto o composto 13 além do composto 9 inibem fortemente a AChE, sendo inclusive mais inibidores que o Propoxur, utilizado como padrão.Tese (Doutorado em Química) - Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Seropédica. Orientação: João Batista Neves da Costa (UFRRJ); Coorientação: Otniel Freitas Silva (CTAA)

Synthesis and characterization of new dialkylacylphosphonylhydrazones.

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Characterization of the vortex-pair interaction law and nonlinear mobility effects

Employing nematic liquid crystals in a homeotropic cell with a photosensitive wall, dissipative vortex pairs are selectively induced by external illumination and the interaction law is characterized for pairs of opposite topological charges. Contrary to the phenomenological fit with a force inversely proportional to the distance, the data provide evidence that nonlinear mobility effects must be taken into account. The observations lead to a reconciliation of experiments with theory

T-cell derived acetylcholine aids host defenses during enteric bacterial infection with Citrobacter rodentium.

The regulation of mucosal immune function is critical to host protection from enteric pathogens but is incompletely understood. The nervous system and the neurotransmitter acetylcholine play an integral part in host defense against enteric bacterial pathogens. Here we report that acetylcholine producing-T-cells, as a non-neuronal source of ACh, were recruited to the colon during infection with the mouse pathogen Citrobacter rodentium. These ChAT+ T-cells did not exclusively belong to one Th subset and were able to produce IFNγ, IL-17A and IL-22. To interrogate the possible protective effect of acetylcholine released from these cells during enteric infection, T-cells were rendered deficient in their ability to produce acetylcholine through a conditional gene knockout approach. Significantly increased C. rodentium burden was observed in the colon from conditional KO (cKO) compared to WT mice at 10 days post-infection. This increased bacterial burden in cKO mice was associated with increased expression of the cytokines IL-1β, IL-6, and TNFα, but without significant changes in T-cell and ILC associated IL-17A, IL-22, and IFNγ, or epithelial expression of antimicrobial peptides, compared to WT mice. Despite the increased expression of pro-inflammatory cytokines during C. rodentium infection, inducible nitric oxide synthase (Nos2) expression was significantly reduced in intestinal epithelial cells of ChAT T-cell cKO mice 10 days post-infection. Additionally, a cholinergic agonist enhanced IFNγ-induced Nos2 expression in intestinal epithelial cell in vitro. These findings demonstrated that acetylcholine, produced by specialized T-cells that are recruited during C. rodentium infection, are a key mediator in host-microbe interactions and mucosal defenses

Fermionic wave functions and Grassmann fields as possible sources of dark energy

We study a cosmological model with a fermionic field which can be interpreted as a source of dark energy in the universe. Two different approaches were considered, the first one with a massless fermionic field represented by a standard wave-function and the second one where a massive field is a Grassmann variable. {The first case naturally reduces to a XCDM model with a constant equation of state parameter, while the last case reproduces a $w(z)$CDM model for a massive field}, and in the massless limit, the intrinsic grassmannian property of the field leads always to a vacuum equation of state parameter, irrespective the specific form of the potential. Both cases leads to a dark energy contribution of the fermionic sector. The models are totally compatible with recent cosmological data from Supernovae, BAO and Hubble parameter measurements. A brief study of linear evolution of density perturbations shows that some of the small scale problems related to standard model can be at least alleviated.Comment: 21 pages, 5 figures, final version publishe

Surface alignment of ferroelectric nematic liquid crystals

none8The success of nematic liquid crystals in displays and optical applications is due to the combination of their optical uniaxiality, fluidity, elasticity, responsiveness to electric fields and controllable coupling of the molecular orientation at the interface with solid surfaces. The discovery of a polar nematic phase opens new possibilities for liquid crystal-based applications, but also requires a new study of how this phase couples with surfaces. Here we explore the surface alignment of the ferroelectric nematic phase by testing different rubbed and unrubbed substrates that differ in coupling strength and anchoring orientation and find a variety of behaviors - in terms of nematic orientation, topological defects and electric field response - that are specific to the ferroelectric nematic phase and can be understood as a consequence of the polar symmetry breaking. In particular, we show that by using rubbed polymer surfaces it is easy to produce cells with a planar polar preferential alignment and that cell electrostatics (e.g.grounding the electrodes) has a remarkable effect on the overall homogeneity of the ferroelectric ordering.openCaimi F.; Nava G.; Barboza R.; Clark N.A.; Korblova E.; Walba D.M.; Bellini T.; Lucchetti L.Caimi, F.; Nava, G.; Barboza, R.; Clark, N. A.; Korblova, E.; Walba, D. M.; Bellini, T.; Lucchetti, L