Métodos para superação da dormência em sementes de taxibranco (Tachigali vulgaris L.F Gomes da Silva E H.C Lima).

O Tachigali vulgaris , conhecido vulgarmente como Taxi - Branco ou Carvoeiro,é uma espécie leguminosa arbórea nativa da Amazônia brasileiraexigente em luz (heliófita) e de rápido crescimento, sua madeira apresenta qualidade superior para lenha e carvão, e tem como principal forma de propagação a via sexuada, apesar da baixa taxa de germinação naturaldas sementes

Anatomia foliar de croton cajucara Benth. (Euphorbiaceae) como contribuição ao estudo farmacognóstico de plantas da região amazônica.

As folhas de Croton cajucara popularmente conhecida por "sacaca", são utilizadas na medicina popular devido às propriedades curativas que lhe são atribuídas, tais como antiinflamatório, diurético e anticolesterolemiante. Objetivando contribuir com estudos fitoterápicos e cosméticos, uma vez que o óleo essencial de C. cajucara é utilizado como fixador de perfumes, realizou-se estudo anatômico da folha desta espécie, destacando-se as estruturas secretoras de óleo essencial. O material pesquisado foi coletado no Banco de Germoplasma da EMBRAPA Amazônia Ocidental-AM e na área agrícola da Faculdade de Ciências Agrárias da Universidade Federal do Amazonas. Aepiderme foliar é constituída por apenas um estrato de células de formato irregular, justapostas, com paredes periclinais e anticlinais sinuosas, revestidas por uma cutícula lisa e espessa e uma camada de cera epicuticular. A folha é anfiestomática com estômatos do tipo paracítico. Em ambas as faces foram observados tricomas do tipo multiradiado, lepidoto e estrelado. Células secretoras de óleo essencial foram encontradas na base dos tricomas do tipo estrelado e, freqüentemente, dispersas no mesofilo. Por meio da técnica de extração por arraste de vapor d'água obteve-se aproximadamente 1mL de óleo por 1 kg de folhas frescas, cujo teor de linalol foi de 37,6%, por cromatografia gasosa/espectrometria de massa.Disponível também on-line

Complementary action of chemical and electrical synapses to perception

Acknowledgements This study was possible by partial financial support from the following agencies: Fundação Araucária, EPSRC-EP/I032606/1, CNPq No. 441553/2014-1, CAPES No. 17656-12-5 and Science Without Borders Program— Process Nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPostprin

The anticancer properties of dietary polyphenols and its relation with apoptosis

Aberrantly regulated apoptosis is involved in the pathogenesis of several diseases and defective apoptosis leads to uncontrolled cell proliferation and tumorigenesis. Cancer is an example of a pathologic condition where the normal mechanisms of cell cycle regulation are dysfunctional either by excessive cell proliferation, inhibited/suppressed apoptosis or both. Dietary habits are estimated to contribute to, at least, one third of all human cancers, showing that dietary components can exacerbate or interfere with carcinogenesis. However, several epidemiological studies have revealed that some dietary factors can decrease the risk of different types of cancer. Apoptosis is suggested to be a crucial mechanism for the chemopreventive properties associated with several dietary factors by eliminating potentially deleterious (damaged/mutated) cells. Food, a readily available item, contains several promising chemopreventive agents. Polyphenols are serious candidates since they are responsible for the cancer protective properties of a diet rich in vegetables and fruits: numerous phenolic compounds showed antiproliferative and cytotoxic effects, and more specifically pro-apoptotic activities, in several cancer cells lines and animal tumor models. The aim of the present review is to analyze and summarize several aspects related to the molecular mechanisms of apoptosis induced by dietary factors with particular emphasis on polyphenols. Dietary factors that can activate cell death signals and induce apoptosis, preferentially in precancerous or malignant cells, and the study of their apoptotic inducing targets can represent a mean to devise new strategies for cancer prevention in the future

Improving the Knowledge on Seismogenic Sources in the Lower Tagus Valley for Seismic Hazard Purposes

The Lower Tagus Valley, that includes the metropolitan area of Lisbon, has been struck by several earthquakes which produced significant material damage and loss of lives. Their exact location remains unknown. Our goal is to shed some light into the seismogenic sources in the area using seismic reflection and geological data. In areas with no seismic coverage, potential-field data interpretation was carried out. Seismicity was overlaid to the potential seismogenic structures and high-resolution data was acquired in order to confirm which structures have been active into the Quaternary. Three major fault-zones affecting the Neogene were identified: V. F. Xira, Samora-Alcochete and Pinhal Novo. For the first fault, strong evidences suggest it is active. The other two fault-zones and other structures previously unknown can be correlated with several epicentres. Empirical relationships between maximum moment magnitude and fault area indicate that MW > 6.5 earthquakes can be expected for the larger structures

Carotenoides Pro-vitamina A em frutos de bananeira.

Os tipos de carotenóides variam muito nas frutas, sendo que aproximadamente 50 carotenóides possuem atividade pró-vitamina A. Dentre esses o β-caroteno é o mais importante e abundante em alimentos, seguido do α-caroteno e β-criptoxantina, os quais possuem a metade da atividade de vitamina A, comparativamente ao primeiro caroteno. Outros carotenóides não pró-vitamina A, porém com efeitos relevantes à saúde humana (e.g., antioxidante, antitumoral e inibidores da degeneração macular), também ocorrem em alimentos (luteína, zeaxantina e licopeno, por exemplo - RODRIGUEZ-AMAYA, 2001) e sua identificação em frutos de bananeira é considerado relevante. A banana destaca-se pelo seu alto potencial como alimento funcional, devido a seu alto consumo, principalmente em países subdesenvolvidos

Nonequilibrium Probabilistic Dynamics of the Logistic Map at the Edge of Chaos

We consider nonequilibrium probabilistic dynamics in logistic-like maps $x_{t+1}=1-a|x_t|^z$, $(z>1)$ at their chaos threshold: We first introduce many initial conditions within one among $W>>1$ intervals partitioning the phase space and focus on the unique value $q_{sen}<1$ for which the entropic form $S_q \equiv \frac{1-\sum_{i=1}^{W} p_i^q}{q-1}$ {\it linearly} increases with time. We then verify that $S_{q_{sen}}(t) - S_{q_{sen}}(\infty)$ vanishes like $t^{-1/[q_{rel}(W)-1]}$ [$q_{rel}(W)>1$]. We finally exhibit a new finite-size scaling, $q_{rel}(\infty) - q_{rel}(W) \propto W^{-|q_{sen}|}$. This establishes quantitatively, for the first time, a long pursued relation between sensitivity to the initial conditions and relaxation, concepts which play central roles in nonextensive statistical mechanics.Comment: Final version with new Title and small modifications. REVTeX, 8 pages and 4 eps figure

Alterations in brain connectivity due to plasticity and synaptic delay

Brain plasticity refers to brain's ability to change neuronal connections, as a result of environmental stimuli, new experiences, or damage. In this work, we study the effects of the synaptic delay on both the coupling strengths and synchronisation in a neuronal network with synaptic plasticity. We build a network of Hodgkin-Huxley neurons, where the plasticity is given by the Hebbian rules. We verify that without time delay the excitatory synapses became stronger from the high frequency to low frequency neurons and the inhibitory synapses increases in the opposite way, when the delay is increased the network presents a non-trivial topology. Regarding the synchronisation, only for small values of the synaptic delay this phenomenon is observed