•Monocular occlusion was used as model of amblyopia in Long-Evan rats.•Binocular visual stereopsis was affected.•Anodal tDCS increase visual stereopsis of amblyopic animals.•PET scans showed a ...functional asymmetry between both hemispheres with a decreased 18F-FDG uptake in the visual cortex of amblyopic rats.
Amblyopia or lazy eye is a neurodevelopmental disorder that arises during the infancy and is caused by the interruption of binocular sensory activity before maturation of the nervous system. This impairment causes long-term deterioration of visual skills, particularly visual acuity and depth perception. Although visual function recovery has been supposed to be decreased with age as consequence of reduced neuronal plasticity, recent studies have shown that it is possible to promote plasticity and neurorestoration in the adult brain. Thus, transcranial direct current stimulation (tDCS) has been shown effective to treat amblyopia in the adulthood. In the present work we used postnatal monocular deprivation in Long Evans rats as an experimental model of amblyopia and the cliff test task to assess depth perception. Functional brain imaging PET was used to assess the effect of tDCS on cortical and subcortical activity. Visually deprived animals ability to perceive depth in the cliff test was significantly reduced in comparison to their controls. However, after 8 sessions of tDCS applied through 8 consecutive days, depth perception of amblyopic treated animals improved reaching control level. PET data showed 18F-FDG uptake asymmetries in the visual cortex of amblyopic animals, which disappeared after tDCS treatment. The possibility of cortical reorganization and stereoscopy recovery following brain stimulation points at tDCS as a useful strategy for treating amblyopia in adulthood. Furthermore, monocular deprivation in Long Evans rats is a valuable research model to study visual cortex mechanisms involved in depth perception and neural restoration after brain stimulation.
Carotenoids are the most common pigments in nature and are synthesized by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis ...photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functions of carotenoids relevant for life on earth. Biological properties of carotenoids allow for a wide range of commercial applications. Indeed, recent interest in the carotenoids has been mainly for their nutraceutical properties. A large number of scientific studies have confirmed the benefits of carotenoids to health and their use for this purpose is growing rapidly. In addition, carotenoids have traditionally been used in food and animal feed for their color properties. Carotenoids are also known to improve consumer perception of quality; an example is the addition of carotenoids to fish feed to impart color to farmed salmon.
The productivity of a vertical outdoor photobioreactor was quantitatively assessed and compared to a horizontal reactor. Daily light cycles in southern Spain were simulated and applied to grow the ...microalgae Chlorella sorokiniana in a flat panel photobioreactor.
The maximal irradiance around noon differs from 400μmolphotonsm−2s−1 in the vertical position to 1800μmolphotonsm−2s−1 in the horizontal position. The highest volumetric productivity was achieved in the simulated horizontal position, 4gkg culture−1d−1. The highest photosynthetic efficiency was found for the vertical simulation, 1.3g of biomass produced per mol of PAR photons supplied, which compares favorably to the horizontal position (0.85gmol−1) and to the theoretical maximal yield (1.8gmol−1). These results prove that productivity per unit of ground area could be greatly enhanced by placing the photobioreactors vertically.
Maximal productivity of a 14 mm light-path panel photobioreactor under high irradiance was determined. Under continuous illumination of 2,100 μmol photons m⁻² s⁻¹ with red light emitting diodes ...(LEDs) the effect of dilution rate on photobioreactor productivity was studied. The light intensity used in this work is similar to the maximal irradiance on a horizontal surface at latitudes lower than 37°. Chlorella sorokiniana, a fast-growing green microalga, was used as a reference strain in this study. The dilution rate was varied from 0.06 to 0.26 h⁻¹. The maximal productivity was reached at a dilution rate of 0.24 h⁻¹, with a value of 7.7 g dw m⁻² h⁻¹ (m² of illuminated photobioreactor surface) and a volumetric productivity of 0.5 g dw L⁻¹ h⁻¹. At this dilution rate the biomass concentration inside the reactor was 2.1 g L⁻¹ and the photosynthetic efficiency was 1.0 g dw mol photons. This biomass yield on light energy is high but still lower than the theoretical maximal yield of 1.8 g mol photons⁻¹ which must be related to photosaturation and thermal dissipation of absorbed light energy. Biotechnol. Bioeng. 2009; 104: 352-359
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