Multi-scale modeling and mechanical performance characterization of stingray skeleton-inspired tessellations

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordSharks and rays have distinctive skeletons among vertebrate animals, consisting primarily of unmineralized cartilage wrapped in a surface tessellation of minute polygonal tiles called tesserae, linked by unmineralized collagenous fibers. The discrete combination of hard and soft tissues is hypothesized to enhance the mechanical performance of tessellated cartilage (which performs many of the same functional roles as bone) by providing either rigidity or flexibility, depending on the nature of the applied load. These mechanisms and the effect of tesserae ultrastructure on cartilage mechanics, however, have never been demonstrated in the actual tissue, nor in bio-accurate models. Here, we develop bio-inspired three-dimensional tesserae computer models, incorporating material properties and ultrastructural features from natural tessellated cartilage. The geometries of ultrastructural features were varied parametrically, and the effective modulus of whole tesserae was evaluated using finite element analysis (FEA) to determine the roles of ultrastructural features in mechanics. Whereas altering some structural features had no effect on the macroscopic in-plane modulus of tesserae, a three-fold increase in the contact surface area between two adjacent tesserae increased the effective modulus of tesserae by 6%. Modeled stress distributions suggest that tesseral ‘spokes’ (distinct hypermineralized features in tesserae) bear maximum stresses in the skeleton and serve to funnel stresses to particular populations of cells in tesserae, while spokes’ lamellated structure likely helps dissipate crack energy, making tesserae more damage-tolerant. Simulations of multi-tesseral arrays showed that maximum stresses in tension and compression are borne by different tissues, supporting hypotheses of multi-functional properties of tessellated cartilage. Further, tesseral array models showed that minor alterations to tesserae/joint shape and/or material properties can be used to tune the mechanical behavior of the whole tiled composite. Our models provide the first functional understanding of the distinct morphologies of spokes and of ‘stellate’ tesserae (a tesseral shape observed first over 150 years ago), while also being useful drivers for hypotheses of growth, mechanics, load management, and the prevention and ‘directing’ of cracks in tessellated cartilage, as well as other biological composites. Additionally, these results establish guidelines and design principles for bio-inspired, tunable tiled materials

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Not AvailablePengba, Osteobrama belangeri (Valenciennes, 1844) is considered as one of the candidate species for diversification of aquaculture. However, only scanty information is available on its nutrient requirements. Hence, the present study was conducted on growth and digestive enzyme activities of pengba fry in response to different dietary protein levels. Six semi-purified isocaloric diets were formulated with different levels of protein at 5% increments (25, 30, 35, 40, 45 and 50%) and fed to different groups of pengba fry for a period of 60 days. Survival of fish was significantly influenced by different protein levels (p0.05) variation among dietary treatments. The activity of proteolytic enzymes (proteases, typsin and chymotrypsin) and acid phosphatase were signicantly (p<0.05) enhanced by dietary protein levels up to 45%, which were found to decline thereafter. Amylase activity was significantly decreased as protein levels increased in the diet. Lipase and alkaline phosphatase activities were not influenced by dietary protein levels. In the present study, penbga fry fed with 45% protein diet, showed the best growth performance and highest digestive enzyme activities. The activity of digestive enzymes in the gut clearly demonstrated that the proteolytic enzymes are activated in response to dietary protein utilisation and also revealed that pengba fry may require high protein (45%) diet for better growth and survival. Second order polynomial regression analysis revealed that the maximum protein requirement of pengba fry was 45.1% (r2 = 0.90). The findings of the study is expected to have significant implications for feed development for pengba aquaculturNot Availabl

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Not AvailableAn experiment of 36 days duration was conducted to study growth performance of goldfish Carassius auratus and basil Ocimum basilicum reared in a media bed aquaponic system. Goldfish fry (3.32 ± 0.45 g and 4.20 ± 0.39 cm) were stocked in rectangular 75 l capacity (water volume of 50 l) plastic tanks at three different stocking densities viz., 500 m-3 (T1), 600 m-3 (T2) and 700 m-3 (T3), respectively and basil plants were planted at a density of 20 m-2, i.e., 10 plants 0.44 m-2 in the rectangular plastic tanks filled with crushed stone media. The goldfish fry were fed with artificial feed (33% protein) at 5% of body weight in equal proportions, two times a day. Control (C) group was set with only basil plants. Growth parameters of goldfish such as length gain (%), weight gain (%) and specific growth rate (% d-1) were significantly higher in T3 (p<0.05) as compared to T1 and T2. However, feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ between treatments. Similarly, basil plant growth in terms of height gain (%) and leaves yield (nos. plant-1) were found to be highest in T3 which was significantly different from T1, T2 and control (C). Throughout the experimental period, values of water parameters in all the treatments were found to be in favourable ranges. From the results of the present study, it could be concluded that for maintaining good water quality with highest production in media bed aquaponics, the optimum stocking density is 700 m-3 for goldfish fry and 10 plants per 0.44 m2 for basil plants.Not Availabl

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Not AvailableRise in temperature directly affects the poikilothermic aquatic animals such as fishes influencing their population biomass and recruitment. With this perspective, a study on spatial-temporal distribution of Indian oil sardine along south-west coast of India (SW) was conducted by classifying the study area into three strata namely: southern, central and northern region. The data was collected and segregated into three seasons, i.e. pre-monsoon, monsoon and post-monsoon. The trend for sea surface temperature was analyzed and compared among three strata and seasons. The trend of standardized catch per hour for all strata and season was also analyzed, along with observation on gear-wise catch of Indian oil sardine. This study indicates towards latitudinal extension and seasonal changes of Indian oil sardine population, besides changing its distribution into deeper water for avoiding the adverse impact of rising temperature.Not Availabl

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Not AvailableAn analysis was carried out on monthly spatial distribution and unusual congregation of Indian squid (Uroteuthis (Photololigo) duvaucelii) off Maharashtra coast. Decadal, annual and monthly squid landing data were taken from National Marine Living Resources Data Centre (NMLRDC) of ICAR-CMFRI. Onboard fisheries information were collected from multi-day trawlers operating from Mumbai and Ratnagiri. Ocean environment parameters coming from Copernicus Marine Service Information with 1/12 degree horizontal resolution and 50 vertical depth level and OSCAR (Ocean Surface Current Analysis Real-time) near-surface ocean current estimates was derived using quasi-linear and steady flow momentum equations on a 1/3 degree grid with a 5 day resolution. In last decade, contribution of squid to total marine fish landing of Maharashtra rose from 2% to 7.3%. The decadal landing shows two peaks in 2012 and 2017. Indian squid landing in 2017 shows two peak, one during August to October confined to 150 N to 170 N latitude in 15 to 60 m depth off south Maharashtra and second in summer, during March-April months widely scattered in north and south Maharashtra. The unusual abundance of Indian squid during mid-October to mid- November 2017 were attributed to rise in coastal surface and subsurface temperature. Catch per hour of trawl and SST shows strong positive correlation (0.79) during the same periodNot Availabl