Avaliação do efeito de formulações com o látex da Euphorbia tirucalli na terapêutica tópica de feridas cutâneas: aspectos clínicos e histopatológicos

Este trabalho objetiva avaliar o efeito do tratamento com soluções aquosas em diferentes concentrações do látex oriundo do aveloz (Euphorbia tirucalli) no processo cicatricial por segunda intenção, de feridas cutâneas experimentais em ratos. Foram utilizados 96 ratos divididos em oito grupos. As feridas foram confeccionadas cirurgicamente, na região lateral direita da linha dorsal. O látex da Euphorbia tirucalli foi coletado e diluído em seis concentrações: 50%, 25%, 12,5%, 6,25%, 3,12% e 1,6%. Para comparação de resultados utilizou-se para controle negativo, água destilada e para controle positivo, pomada a base de clostebol. Após 24 horas da cirurgia, iniciou-se o tratamento duas vezes ao dia. A evolução da cicatrização foi avaliada diariamente e a mensuração da área das lesões realizada a cada quatro dias. Realizou-se coleta de material para avaliação histopatológica da cicatrização. Os resultados da avaliação macroscópica foram submetidos à Análise de Variância e comparação de médias pelo Teste de Tukey ao nível de 5% de probabilidade, e os da avaliação histopatológica foram analisados pelo Teste de Kruskall-Wallis a 5% de probabilidade. O uso de formulações tópicas à base de látex de Euphorbia tirucalli, em distintas concentrações, não reduz o tempo final de cicatrização de feridas experimentais do dorso de ratos. Soluções aquosas do látex nas concentrações de 6,25% e 3,12% podem ser alternativamente empregadas na cicatrização de feridas, pois induzem menor hiperemia e exsudação e desencadeiam uma reparação tissular esteticamente melhor

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

Random interactions and spin-glass thermodynamic transition in the hole-doped Haldane system Y2−x_{2-x}Cax_xBaNiO5_5

Magnetization, DC and AC bulk susceptibility of the $S$=1 Haldane chain system doped with electronic holes, Y$_{2-x}$Ca$_x$BaNiO$_5$ (0$\leq$x$\leq$0.20), have been measured and analyzed. The most striking results are (i) a sub-Curie power law behavior of the linear susceptibility, $\chi (T)$$\sim$ $T$$^{-\alpha}$, for temperature lower than the Haldane gap of the undoped compound (x=0) (ii) the existence of a spin-glass thermodynamic transition at $T$$_g$ = 2-3 K. These findings are consistent with (i) random couplings within the chains between the spin degrees of freedom induced by hole doping, (ii) the existence of ferromagnetic bonds that induce magnetic frustration when interchain interactions come into play at low temperature.Comment: 4 pages, 4 figures, to appear in Phys. Rev.

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

Electron Spin Resonance of defects in the Haldane System Y(2)BaNiO(5)

We calculate the electron paramagnetic resonance (EPR) spectra of the antiferromagnetic spin-1 chain compound Y(2)BaNi(1-x)Mg(x)O(5) for different values of x and temperature T much lower than the Haldane gap (~100K). The low-energy spectrum of an anisotropic Heisenberg Hamiltonian, with all parameters determined from experiment, has been solved using DMRG. The observed EPR spectra are quantitatively reproduced by this model. The presence of end-chain S=1/2 states is clearly observed as the main peak in the spectrum and the remaining structure is completely understood.Comment: 5 pages, 4 figures include

Generalized Jordan-Wigner Transformations

We introduce a new spin-fermion mapping, for arbitrary spin $S$ generating the SU(2) group algebra, that constitutes a natural generalization of the Jordan-Wigner transformation for $S=1/2$. The mapping, valid for regular lattices in any spatial dimension $d$, serves to unravel hidden symmetries in one representation that are manifest in the other. We illustrate the power of the transformation by finding exact solutions to lattice models previously unsolved by standard techniques. We also present a proof of the existence of the Haldane gap in $S=$1 bilinear nearest-neighbors Heisenberg spin chains and discuss the relevance of the mapping to models of strongly correlated electrons. Moreover, we present a general spin-anyon mapping for the case $d \leq 2$.Comment: 5 pages, 1 psfigur

Pathways to Mathematics College Readiness in Maine

The goal of this study was to examine the pathways to being college ready in mathematics. Students who enter high school already having demonstrated mathematics proficiency on a standardized test in the 8th grade have already taken a significant step towards being college ready. The best scenario is to enter high school proficient in mathematics and having already completed Algebra I, then to complete at least Algebra II and Calculus before graduating from high school. Students completing this pathway are virtually guaranteed to be college ready in mathematics. There also is an alternative path to being college ready. Being proficient entering high school, and then completing a course sequence that includes at least Algebra I, Algebra II, and pre-Calculus significantly increased students\u27 chances of being college ready in mathematics. Thus, it appears 8th grade proficiency is key to becoming college ready in mathematics. It affords opportunities for students to complete Algebra I before entering high school and then take higher level mathematics courses in high school. Alternatively, even if students wait to take Algebra I in high school, if they are proficient and complete at least pre-Calculus, they have a high likelihood of being college ready. The key is 8th grade mathematics proficiency. It opens the gate to a successful high school and college experience in mathematics. The typical sequence of courses completed by most high school students is Algebra I, Geometry, and Algebra II. The Common Core State Standards Initiative (2012) has endorsed this three course sequence as preparing students for college. However, the evidence from this study does not support this endorsement. Completing Geometry does not substantially ensure college readiness, nor does completing Algebra II ensure college readiness. Students also need to successfully complete either a pre-Calculus or Calculus course in high school to be college ready