Sixty sexually mature purebred black-skinned Archachatina marginata snails with weight ranging from 120.50 g to 135.70 g were used to generate eggs in this study. The eggs collected were incubated in a chamber filled ...Sixty sexually mature purebred black-skinned Archachatina marginata snails with weight ranging from 120.50 g to 135.70 g were used to generate eggs in this study. The eggs collected were incubated in a chamber filled with loamy soil for appropriate observation and assessment (cracking at four days intervals to check snailet’s development). Results obtained from the study showed that at laying snail egg weights ranged from 1.54 - 2.45 g (mean of 2.00 g). The egg lengths and widths ranged from 13.50 - 16.90 mm (mean of 15.20 mm) and 10.00 - 12.70 mm (mean of 11.40 mm) respectively. The results also revealed that at laying (day one) the egg content was translucent or clear (blank) when observed with light from a powered microscope. Observation of eggs on day four showed the formation of embryo with a semi-transparent cup attached to a long string body. On day 12, some specific organs of the snailet had developed, and there was a reduction in the liquid content. On day 28, the snailet was fully formed, but the shell still contained very small volume of liquid. The snailet hatched on day 29.展开更多
The present study was done using two concentrations of the photosensitizer Hematoporphyrin coated Gold Nanoparticles (HpdGNP3) (5x10–6 , 5x10–5 mole/dicemeter–3), to evaluate their efficacy on survival rate, egg-la...The present study was done using two concentrations of the photosensitizer Hematoporphyrin coated Gold Nanoparticles (HpdGNP3) (5x10–6 , 5x10–5 mole/dicemeter–3), to evaluate their efficacy on survival rate, egg-laying capacity of Biomphalaria alexandrina snails and on histological deteriorations in their hermaphrodite gland. B. alexandrina snails were incubated for 12 hours at each tested concentration in the dark, thereafter they were exposed to direct sunlight (336.2 W/m2) for either 2 or 4 hours followed by 24 hours of recovery. Control snails were treated with these concentrations without exposure to light irradiance. Another experiment was carried out simultaneously and the snails were left for 4 weeks of recovery to evaluate their egg-laying capacity (Mx). The results indicate that 5x10–5 Mdm–3 (HpdGNPs) with 4 hours of exposure sunlight suppressed the survival rate of B. alexandrina snails by 50%. Meanwhile, control snails incubated with 5x10–5 Mdm–3 HpdGNPs were not affected and still alive (100%). For snail’s fecundity (Mx), treated snails laid low number of eggs throughout the recov-ery period (4 weeks), in comparison with that of control ones. The highest value of Mx for snails treated with 5x10–5 Mdm–3 Hpd coated GNPs was recorded at the 3rd week of recovery period, being 6.7 eggs/snail, compared to 37.6 eggs/control snail. This has a negative reflect on the reproductive rate (Ro) of treated snails as it was reduced under these conditions by 76.6% and 86.1%, respectively.Histological tests re-vealed injuries in spermatocytes, oocytes, several degenerations of B.alexandrina hermaphrodite gland then evacuations in many gonad’s cells which severely suppressed their capacity for egg-laying. It is concluded from the present work that exposing B. alexandrina snails to sublethal concentrations of the photosensiter Hpd coated GNPs (12 hours incubation, 4 hours exposure to 336.2 W/m2) significantly reduced their reproductive capacity that may have a negative reflect on schistosomiasis transmis-sion.展开更多
The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is propose...The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is proposed, and the performance of the penetration and extraction are analyzed by numerical method. The geometric contour of egg and snail shell is measured, and its mathematical model is established respectively. According to the structure of existing spudcan of jack-up platform, three kinds of typical biomimetic spudcan are designed. Furthermore, numerical analysis models of biomimetic spudcan are established respectively to study the soil structure interaction mechanism in the process of penetration and extraction, and contrastive analysis of resistance characteristics are carried out. To conclude, the results show that the biomimetic spudcan facilitates the platform installation, and it is also beneficial to the improvement of the bearing capacity of spudcan.展开更多
文摘Sixty sexually mature purebred black-skinned Archachatina marginata snails with weight ranging from 120.50 g to 135.70 g were used to generate eggs in this study. The eggs collected were incubated in a chamber filled with loamy soil for appropriate observation and assessment (cracking at four days intervals to check snailet’s development). Results obtained from the study showed that at laying snail egg weights ranged from 1.54 - 2.45 g (mean of 2.00 g). The egg lengths and widths ranged from 13.50 - 16.90 mm (mean of 15.20 mm) and 10.00 - 12.70 mm (mean of 11.40 mm) respectively. The results also revealed that at laying (day one) the egg content was translucent or clear (blank) when observed with light from a powered microscope. Observation of eggs on day four showed the formation of embryo with a semi-transparent cup attached to a long string body. On day 12, some specific organs of the snailet had developed, and there was a reduction in the liquid content. On day 28, the snailet was fully formed, but the shell still contained very small volume of liquid. The snailet hatched on day 29.
文摘The present study was done using two concentrations of the photosensitizer Hematoporphyrin coated Gold Nanoparticles (HpdGNP3) (5x10–6 , 5x10–5 mole/dicemeter–3), to evaluate their efficacy on survival rate, egg-laying capacity of Biomphalaria alexandrina snails and on histological deteriorations in their hermaphrodite gland. B. alexandrina snails were incubated for 12 hours at each tested concentration in the dark, thereafter they were exposed to direct sunlight (336.2 W/m2) for either 2 or 4 hours followed by 24 hours of recovery. Control snails were treated with these concentrations without exposure to light irradiance. Another experiment was carried out simultaneously and the snails were left for 4 weeks of recovery to evaluate their egg-laying capacity (Mx). The results indicate that 5x10–5 Mdm–3 (HpdGNPs) with 4 hours of exposure sunlight suppressed the survival rate of B. alexandrina snails by 50%. Meanwhile, control snails incubated with 5x10–5 Mdm–3 HpdGNPs were not affected and still alive (100%). For snail’s fecundity (Mx), treated snails laid low number of eggs throughout the recov-ery period (4 weeks), in comparison with that of control ones. The highest value of Mx for snails treated with 5x10–5 Mdm–3 Hpd coated GNPs was recorded at the 3rd week of recovery period, being 6.7 eggs/snail, compared to 37.6 eggs/control snail. This has a negative reflect on the reproductive rate (Ro) of treated snails as it was reduced under these conditions by 76.6% and 86.1%, respectively.Histological tests re-vealed injuries in spermatocytes, oocytes, several degenerations of B.alexandrina hermaphrodite gland then evacuations in many gonad’s cells which severely suppressed their capacity for egg-laying. It is concluded from the present work that exposing B. alexandrina snails to sublethal concentrations of the photosensiter Hpd coated GNPs (12 hours incubation, 4 hours exposure to 336.2 W/m2) significantly reduced their reproductive capacity that may have a negative reflect on schistosomiasis transmis-sion.
基金financially supported by the Postgraduate Research & Practice Innovation Program of Jiangsu Province(Grant No.KYCX18_2311)
文摘The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is proposed, and the performance of the penetration and extraction are analyzed by numerical method. The geometric contour of egg and snail shell is measured, and its mathematical model is established respectively. According to the structure of existing spudcan of jack-up platform, three kinds of typical biomimetic spudcan are designed. Furthermore, numerical analysis models of biomimetic spudcan are established respectively to study the soil structure interaction mechanism in the process of penetration and extraction, and contrastive analysis of resistance characteristics are carried out. To conclude, the results show that the biomimetic spudcan facilitates the platform installation, and it is also beneficial to the improvement of the bearing capacity of spudcan.
