Atividade antihelmintica in vitro do óleo essencial de Lippia alba no controle de monogenóides de tambaqui (Colossoma macropomum).

O objetivo deste estudo foi avaliar a atividade antihelmíntica in vitro do óleo essencial de Lippia alba no controle de monogenóides de tambaqui (Colossoma macropomum)

Playing the blues, the greens and the reds with cellulose-based structural colours

POCI- 01-0145-FEDER-007688 (Reference UIDB/50025/2020-2023) PTDC/CTM-BIO/6178/2014 M-ERA-NET2/0007/2016 PTDC/CTM-REF/30529/2017 EUTOPIA CA17139 Slovenian Research Agency Grant Z1-5441 P1-0099Structural vivid colours can arise from the interference of light reflected from structures exhibiting periodicity on scales in the range of visible wavelengths. This effect is observed with light reflected from cell-walls of some plants and exoskeletons of certain insects. Sometimes the colour sequence observed for these structures consists of nearly circular concentric rings that vary in colour from Red, Orange, Yellow, Green, Cyan to Blue, from the periphery to the centre, similarly to the colour scheme sequence observed for the rainbow (ROYGB). The sequence of colours has been found for solid films obtained from droplets of aqueous cellulose nanocrystals (CNCs) suspensions and attributed to a "coffee ring"effect. In this work, coloured lyotropic solutions and solid films obtained from a cellulose derivative in the presence of trifluoroacetic acid (TFA), which acts as a "reactive solvent", are revisited. The systems were investigated with spectroscopy, using circularly and linearly polarised light, coupled with a polarised optical microscope (POM) and scanning electron microscopy (SEM). The lyotropic cholesteric liquid crystalline solutions were confined in capillaries to simplify 1D molecular diffusion along the capillary where an unexpected sequence of the structural colours was observed. The development and reappearance of the sequence of vivid colours seem consistent with the reaction-diffusion of the "reactive solvent"in the presence of the cellulosic chains. The strong TFA acts as an auto-catalyst for the chemical reaction between TFA and the hydroxyl groups, existing along the cellulosic chain, and diffuses to the top and bottom along the capillaries, carrying dissolved cellulosic chains. Uncovering the precise mechanism of colour sequence and evolution over time in cellulosic lyotropic solutions has important implications for future optical/sensors applications and for the understanding of the development of cellulose-based structures in nature. This journal isauthorsversionpublishe

Colourful patterns in cellulose-based liquid crystals

POCI-01-0145-FEDER-007688 UIDB/50025/2020-2023 EUTOPIA CA17139Cellulose-based thermotropic and lyotropic liquid crystals can be obtained from macromolecules or colloidal particles, such as cellulose nanocrystals. Thermotropic liquid crystals are produced by the effect of temperature, while lyotropic liquid crystals occur in solution for a given range of concentration, pressure, and temperature. Cellulose liquid crystals can form chiral nematic phases characterized by Bragg-type reflections of circularly polarized light. This characteristic is related to a helical structure formed by pseudo nematic layers twisted around an optical axis. The helical structure is characterized by the values of pitch and helicity. The later can be right- (R) or left- (L) handed. Cellulose liquid crystals are well described in literature. They are a source of materials for many applications, including the production of photonic chiral materials. Although many questions remain unanswered such as the origin of helicity of cellulosic chiral structures and those related to out-ofequilibrium systems. In this paper, we are focused at the out-of-equilibrium systems obtained from lyotropic cellulose-based liquid crystals. The development of colorful patterns involving the pitch variation in space and time of self-organized cellulose cholesteric structures is revised.publishersversionpublishe

Consumo de nutrientes em dietas com diferentes proporções do feno de erva sal (Atriplex nummularia Lindl.) para ovinos.

O objetivo deste trabalho foi avaliar o efeito de diferentes proporções do feno da erva-sal (Atriplex nummularia Lindl.) em dietas contendo palma forrageira e uréia, sobre os consumos de água (CH2O), matéria seca (CMS), matéria orgânica (CMO), matéria mineral (CMM), proteína bruta (CPB) e fibra em detergente neutro (CFDN)

Travelling colourful patterns in self-organized cellulose-based liquid crystalline structures

Publisher Copyright: © 2021, The Author(s)Cellulose-based systems are useful for many applications. However, the issue of self-organization under non-equilibrium conditions, which is ubiquitous in living matter, has scarcely been addressed in cellulose-based materials. Here, we show that quasi-2D preparations of a lyotropic cellulose-based cholesteric mesophase display travelling colourful patterns, which are generated by a chemical reaction-diffusion mechanism being simultaneous with the evaporation of solvents at the boundaries. These patterns involve spatial and temporal variation in the amplitude and sign of the helix´s pitch. We propose a simple model, based on a reaction-diffusion mechanism, which simulates the observed spatiotemporal colour behaviour.publishersversionpublishe

Atividade antimicrobiana do óleo essencial de Lippia origanoides frente à Aeromonas hydrophila.

O objetivo deste estudo foi avaliar a atividade antimicrobiana do óleo essencial de Lippia origanoides frente à Aeromonas hydrophila