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The direct thermal polymerization techniques were applied to prepare the graphene oxide (GO)-graphitic carbon nitride (gCN) hybrid structure. The prepared hybrid heterojunction GO-gCN nanosheets were utilized as a photocatalyst to remove model pollutants methylene blue (MB) dye. The basic physio-chemical properties of GO-gCN layered materials have been analyzed by various characterization techniques. In addition, the proposed materials have a higher photocatalytic ability toward the degradation of aqueous solution of MB dye under visible light irradiation within a short treatment time. This is because it's the synergistic effects of GO-gCN layer-by-layer structures produced by π─π stacking with charge-transfer interactions. The gCN with GO composite can able to enhance the charge transfer and light-harvesting properties. Under the influence of photocatalyst, the surface of Graphene oxide undergoes the separation and combination of carbonyl radicals, hydroxyl radicals, epoxy radicals, and electron-hole pairs. This enhances the absorption of visible light and improves the degradation of MB, when GO is incorporated into gCN. The removal efficiency of MB reached up to 82.311% within the short treatment time.

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The optic lobe is the largest brain area within the central nervous system of cephalopods and it plays important roles in the processing of visual information, the regulation of body patterning, and locomotive behavior. The oval squid Sepioteuthis lessoniana has relatively large optic lobes that are responsible for visual communication via dynamic body patterning. It has been observed that the visual behaviors of oval squids change as the animals mature, yet little is known about how the structure of the optic lobes changes during development. The aim of the present study was to characterize the ontogenetic changes in neural organization of the optic lobes of S. lessoniana from late embryonic stage to adulthood. Magnetic resonance imaging and micro-CT scans were acquired to reconstruct the 3D-structure of the optic lobes and examine the external morphology at different developmental stages. In addition, optic lobe slices with nuclear staining were used to reveal changes in the internal morphology throughout development. As oval squids mature, the proportion of the brain making up the optic lobes increases continuously, and the optic lobes appear to have a prominent dent on the ventrolateral side. Inside the optic lobe, the cortex and the medulla expand steadily from the late embryonic stage to adulthood, but the cell islands in the tangential zone of the optic lobe decrease continuously in parallel. Interestingly, the size of the nuclei of cells within the medulla of the optic lobe increases throughout development. These findings suggest that the optic lobe undergoes continuous external morphological change and internal neural reorganization throughout the oval squid's development. These morphological changes in the optic lobe are likely to be responsible for changes in the visuomotor behavior of oval squids from hatching to adulthood.

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The optic lobe is the largest structure in the cuttlefish brain. While the general morphology of the optic lobe in adult cuttlefish has been well described, the 3D structure and ontogenetic development of its neural organization have not been characterized. To correlate observed behavioral changes within the brain structure along the development of this animal, optic lobes from the late embryonic stage to adulthood were examined systematically in the present study. The MRI scan revealed that the so called "cell islands" in the medulla of the cephalopod's optic lobe (Young, 1962, 1974) are in fact a contiguous tree-like structure. Quantification of the neural organizational development of optic lobes showed that structural features of the cortex and radial column zone were established earlier than those of the tangential zone during embryonic and post-hatching stages. Within the cell islands, the density of nuclei was decreased while the size of nuclei was increased during the development. Furthermore, the visual processing area in the optic lobe showed a significant variation in lateralization during embryonic and juvenile stages. Our observation of a continuous increase in neural fibers and nucleus size in the tangential zone of the optic lobe from late embryonic stage to adulthood indicates that the neural organization of the optic lobe is modified along the development of cuttlefish. These findings thus support that the ontogenetic change of the optic lobe is responsible for their continuously increased complexity in body patterning and visuomotor behaviors.

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Giant squids (Architeuthis) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol.22, 683-688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information. In this study, the optic lobe of a giant squid (Architeuthis dux, male, mantle length 89 cm), which was caught by local fishermen off the northeastern coast of Taiwan, was scanned using high-resolution magnetic resonance imaging in order to examine its internal structure. It was evident that the volume ratio of the optic lobe to the eye in the giant squid is much smaller than that in the oval squid (Sepioteuthis lessoniana) and the cuttlefish (Sepia pharaonis). Furthermore, the cell density in the cortex of the optic lobe is significantly higher in the giant squid than in oval squids and cuttlefish, with the relative thickness of the cortex being much larger in Architeuthis optic lobe than in cuttlefish. This indicates that the relative size of the medulla of the optic lobe in the giant squid is disproportionally smaller compared with these two cephalopod species. This morphological study of the giant squid brain, though limited only to the optic lobe, provides the first evidence to support that the optic lobe cortex, the visual information processing area in cephalopods, is well developed in the giant squid. In comparison, the optic lobe medulla, the visuomotor integration centre in cephalopods, is much less developed in the giant squid than other species. This finding suggests that, despite the giant eye and a full-fledged cortex within the optic lobe, the brain of giant squids has not evolved proportionally in terms of performing complex tasks compared with shallow-water cephalopod species.