In order to compare the macrozoobenthic community and sedimentary environment with and without the presence of horseshoe crabs,the benthic macrofauna,sediment grain size,chromium(Cr),cobalt(Co),nickel(Ni),polycyclic a...In order to compare the macrozoobenthic community and sedimentary environment with and without the presence of horseshoe crabs,the benthic macrofauna,sediment grain size,chromium(Cr),cobalt(Co),nickel(Ni),polycyclic aromatic hydrocarbon(PAHs),organic carbon and nitrogen were seasonally investigated at site A(with horseshoe crab presence),sites B and C(without horseshoe crab presence)in the Crocodile Island intertidal zone in Xiamen from June 2018 to July 2019.The results showed that most of the community parameters of benthic macrofauna,population parameters of common benthic macrofauna and environmental parameters were significantly different at the sites with horseshoe crab versus non-horseshoe crab sites.A two-way ANOVA test showed that the densities of Ceratonereis erythraeensis and Sigambra hanaokai had significant site variation.Cluster and nonmetric multi-dimensional scaling(NMDS)analysis showed the community composition of benthic macrofauna was significantly different among the three sampling sites over four seasons.The mean sand content at site A(64.32%)was higher than those at site B(36.01%)and site C(18.86%).Conversely,the mean contents of silt,clay,Cr,Co,Ni,organic carbon,organic nitrogen,phenanthrene,and pyrene at site A were lower than those at site B and site C.These observations are consistent with the expected preferences of horseshoe crabs to live in areas with 60%sand content,which is associated with abundant and edible clamworms in the Crocodile Island intertidal zone,Xiamen.展开更多
Objective: To evaluate normal spermatozoa morphometry and ultrastructure in estuarine crocodile (Crocodylus porosus). Methods: Four adult male crocodiles aged between 12-15 years, with an average snout to tail length ...Objective: To evaluate normal spermatozoa morphometry and ultrastructure in estuarine crocodile (Crocodylus porosus). Methods: Four adult male crocodiles aged between 12-15 years, with an average snout to tail length of (3.15±0.01) m were selected for this study. Manipulation of the phallus digitally from the base of the penis was performed on four adult male crocodiles to facilitate the flow of semen to the sulcus. Semen was collected from all individuals for spermatozoa morphometry and ultrastructure study. Morphometry analysis was performed from eosin-nigrosin stained spermatozoa sample. Scanning electron microscopy was conducted to observe the surface ultrastructure of spermatozoa. Results: The morphology of crocodile spermatozoa was made up of acrosome, head, and tail which corresponded to (5.55±1.20) μm, (12.74±1.57) μm, and (70.67±4.40) μm, respectively. The total length of spermatozoa in estuarine crocodile was measured at (88.96±0.52) μm. The most common spermatozoa abnormalities found in the samples were cytoplasmic droplets. Conclusions: Normal morphology, morphometry of spermatozoa in estuarine crocodile which are vermiform shaped-head with a long tail along with questionably high cytoplasmic droplets count are described in this study.展开更多
Time: a sunny day Place: a river in the forest Characters: Fox, Crocodile(鳄鱼) , Rabbit A, Rabbit B, Little Deer, Mother Deer Scene ⅠStoryteller: There are many animals in the forest. There is a river in the forest,...Time: a sunny day Place: a river in the forest Characters: Fox, Crocodile(鳄鱼) , Rabbit A, Rabbit B, Little Deer, Mother Deer Scene ⅠStoryteller: There are many animals in the forest. There is a river in the forest, too.When the animals are thirsty(口渴的) , they often drink water in the river. But there is a bad big crocodile living in the river too. All the small animals hate him but they are also afraid of him.展开更多
In 1927, when René Lacoste chose the crocodile as his emblem, he had not imagined that 80 years later, millions of people would bear this logo. He could also not imagine that the crocodile would be
Crocodiles,one of the oldest and most resilient species on Earth,have demonstrated remarkable locomotor abilities both on land and in water,evolving over millennia to adapt to diverse environ-ments.In this study,we dr...Crocodiles,one of the oldest and most resilient species on Earth,have demonstrated remarkable locomotor abilities both on land and in water,evolving over millennia to adapt to diverse environ-ments.In this study,we draw inspiration from crocodiles and design a highly biomimetic crocodile robot equipped with multiple degrees of freedom and articulated trunk joints.This design is based on comprehensive analysis of the structural and motion characteristics of real crocodiles.The bionic crocodile robot has a problem of limb-torso incoordination during movement.To solve this problem,we used the D-H method for both forward and inverse kinematics analysis of the robot's legs and spine.Through a series of simulation experiments,we investigated the robot's motion stability,fault tolerance,and adaptability to environments in two motor patterns:with and without spine and tail movements.The experimental results show that the bionic crocodile robot exhibits superior motion performance when the spine and tail cooperate with the extremities.This study not only demonstrates the potential of biomimicry in robotics but also underscores the significance of understanding how nature's designs can inform and enhance technological innovations.展开更多
Cardiovascular disease is a major cause of mortality in diabetic patients due to the heightened oxidative stress and pro-inflammatory state in vascular tissues.Effective approaches targeting cardiovascular health for ...Cardiovascular disease is a major cause of mortality in diabetic patients due to the heightened oxidative stress and pro-inflammatory state in vascular tissues.Effective approaches targeting cardiovascular health for diabetic patients are urgently needed.Crocodile blood,an emerging dietary supplement,was suggested to have anti-oxidative and anti-inflammatory effects in vitro,which have yet to be proven in animal models.This study thereby aimed to evaluate whether crocodile blood can protect vascular function in diabetic mice against oxidation and inflammation.Diabetic db/db mice and their counterparts db/m+mice were treated daily with crocodile blood soluble fraction(CBSF)or vehicle via oral gavage for 4 weeks before their aortae were harvested for endothelium-dependent relaxation(EDR)quantification using wire myograph,which is a well-established functional study for vascular function indication.Organ culture experiments culturing mouse aortae from C57BL/6 J mice with or without IL-1βand CBSF were done to evaluate the direct effect of CBSF on endothelial function.Reactive oxygen species(ROS)levels in mouse aortae were assessed by dihydroethidium(DHE)staining with inflammatory markers in endothelial cells quantified by quantitative polymerase chain reaction(qPCR).CBSF significantly improved deteriorated EDR in db/db diabetic mice through both diet supplementation and direct culture,with suppression of ROS level in mouse aortae.CBSF also maintained EDR and reduced ROS levels in mouse aortae against the presence of pro-inflammatory IL-1β.Under the pro-inflammatory state induced by IL-1β,gene expressions of inflammatory cytokines were downregulated,while the protective transcripts UCP2 and SIRT6 were upregulated in endothelial cells.Our study suggests a novel beneficial effect of crocodile blood on vascular function in diabetic mice and that supplementation of diet with crocodile blood may act as a complementary approach to protect against vascular diseases through anti-oxidation and anti-inflammation in diabetic patients.展开更多
选注者言:本文描述的是澳大利亚的一个鳄鱼保护区里的故事,内容生动可读,信息丰富动人。但是,就语言表达而言,本文出现的一个现象值得读者注意。首先,本文标题中的Rule the Roost是一个英语成语,含义是:当家;为首;为王。而初学者则容易...选注者言:本文描述的是澳大利亚的一个鳄鱼保护区里的故事,内容生动可读,信息丰富动人。但是,就语言表达而言,本文出现的一个现象值得读者注意。首先,本文标题中的Rule the Roost是一个英语成语,含义是:当家;为首;为王。而初学者则容易将此成语当作Rule+the Roost(统治+栖息处)去理解。所幸的是,聪明的读者也能从“统治+栖息处”的意思推断出“当家;为首;为王”的理解,但是,并非所有的英语成语均能如此顺利“推断”,比如,本文的结尾处,出现了plunge pool。什么叫plunge pool是一个习惯搭配,意思是“瀑布下的水潭”,假如,读者不知道这个习惯搭配,而是根据plunge+pool的意思“游泳+池”(plunge确实有“游泳”的意思)去猜想,那就麻烦了!展开更多
The MohroCoulomb criterion has been widely used to explain formation of fractures. However, it fails to explain large strain deformation that widely occurs in nature. There is presently a new theory, the MEMC, which i...The MohroCoulomb criterion has been widely used to explain formation of fractures. However, it fails to explain large strain deformation that widely occurs in nature. There is presently a new theory, the MEMC, which is mathematically expressed as Meff = （（σ1-σ3） L.sin 2α sin α）/2, where σ1-σ3 represents the yield strength of the related rock, L is a unit length and a is the angle between σ1 and deformation bands. This criterion demonstrates that the maximum value appears at angles of ±54.7° to σ1 and there is a slight difference in the moment in the range of 55°±10°. The range covers the whole observations available from nature and experiments. Its major implications include： （1） it can be used to determine the stress state when the related deformation features formed; （2） it provides a new approach to determine the Wk of the related ductile shear zone if only the ratio of the vorticity and strain rate remains fixed; （3） It can be used to explain （a） the obtuse angle in the contraction direction of conjugate kink-bands and extensional crenulation cleavages, （b） formation of low-angle normal faults and high-angle reverse faults, （c） lozenge ductile shear zones in basement terranes, （d） some crocodile structures in seismic profiles and （e） detachment folds in foreland basins.展开更多
The diet of juvenile,including hatchlings and presumed yearlings of the Saltwater Crocodile,Crocodylus porosus,was studied at the Kuching Wetlands National Park,western Sarawak,East Malaysia(Borneo),using both frequen...The diet of juvenile,including hatchlings and presumed yearlings of the Saltwater Crocodile,Crocodylus porosus,was studied at the Kuching Wetlands National Park,western Sarawak,East Malaysia(Borneo),using both frequency of occurrence and volumetric composition of diet through the stomach flushing technique.Crustaceans form the primary component of the diet of juvenile crocodiles,comprising shrimps of the family Atyidae(Caridina sp.,and Penaeus indicus),occurring in the stomach of 17 individuals(53%by occurrence).An estimated 91.7%of hatchlings stomach-flushed had shrimps,and the emergence of hatchlings may be associated by inland migration of its shellfish prey,as reported in the literature.The secondary food item of hatchlings and presumed yearlings was ocypodid crabs,occurring in 16 individuals(in addition to a subadult),and comprise 47%-50%by occurrence.Other items taken incidentally include rodents(in large yearlings,exceeding 100 cm in total length),and fish(in seven hatchlings and in one subadult),or in 29%of total individuals captured(47.7%in hatchlings and 15%in yearlings).A dietary change in ontogeny is therefore evident,as reported earlier in crocodilians.展开更多
The resistance between mud surface and ship-type paddy field machine hull accounts for a certain proportion of the total mechanical power consumption during the operation process.The special characteristic has been fo...The resistance between mud surface and ship-type paddy field machine hull accounts for a certain proportion of the total mechanical power consumption during the operation process.The special characteristic has been found via preliminary study,it showed that when starting or working at low velocity,the resistance is much greater than the machine working at the rated velocity.This characteristic affects the dynamic matching and structural design of the machine.The critical velocity of resistance distortion was around 0.025 m/s under the setting experimental conditions,and the mechanism of resistance distortion under multi-medium was analyzed.Based on water film drag reduction theory,a macroscopic structure of crocodile's abdominal armor biomimetic drag reduction method was proposed.Two kinds of bionic macroscopic structure ship board were fabricated.The macroscopic structure can introduce more water into the bottom surface of the hull;thicken the water film,which can reduce the travel resistance.Design and manufacture a ship-type paddy field experimental setup with velocity control,and compare the traditional smooth surface ship board with the two bionic macroscopic structure surfaces through orthogonal test.The experiment results demonstrated that the ship board with rectangle gully structure has better drag reduction effect than the hexagon one in the lower velocity.But when the travel velocity approach to the resistance distortion critical point,the hexagon gully structure become better than the other one.Through the orthogonal test,the best drag reduction combination is 2.5 kg load weight,0.025 m/s travel velocity with hexagon ship board,which decreases the drag by 6.3%.展开更多
基金the National Key Research and Development Program of China(No.2016YFC0502904)。
文摘In order to compare the macrozoobenthic community and sedimentary environment with and without the presence of horseshoe crabs,the benthic macrofauna,sediment grain size,chromium(Cr),cobalt(Co),nickel(Ni),polycyclic aromatic hydrocarbon(PAHs),organic carbon and nitrogen were seasonally investigated at site A(with horseshoe crab presence),sites B and C(without horseshoe crab presence)in the Crocodile Island intertidal zone in Xiamen from June 2018 to July 2019.The results showed that most of the community parameters of benthic macrofauna,population parameters of common benthic macrofauna and environmental parameters were significantly different at the sites with horseshoe crab versus non-horseshoe crab sites.A two-way ANOVA test showed that the densities of Ceratonereis erythraeensis and Sigambra hanaokai had significant site variation.Cluster and nonmetric multi-dimensional scaling(NMDS)analysis showed the community composition of benthic macrofauna was significantly different among the three sampling sites over four seasons.The mean sand content at site A(64.32%)was higher than those at site B(36.01%)and site C(18.86%).Conversely,the mean contents of silt,clay,Cr,Co,Ni,organic carbon,organic nitrogen,phenanthrene,and pyrene at site A were lower than those at site B and site C.These observations are consistent with the expected preferences of horseshoe crabs to live in areas with 60%sand content,which is associated with abundant and edible clamworms in the Crocodile Island intertidal zone,Xiamen.
文摘Objective: To evaluate normal spermatozoa morphometry and ultrastructure in estuarine crocodile (Crocodylus porosus). Methods: Four adult male crocodiles aged between 12-15 years, with an average snout to tail length of (3.15±0.01) m were selected for this study. Manipulation of the phallus digitally from the base of the penis was performed on four adult male crocodiles to facilitate the flow of semen to the sulcus. Semen was collected from all individuals for spermatozoa morphometry and ultrastructure study. Morphometry analysis was performed from eosin-nigrosin stained spermatozoa sample. Scanning electron microscopy was conducted to observe the surface ultrastructure of spermatozoa. Results: The morphology of crocodile spermatozoa was made up of acrosome, head, and tail which corresponded to (5.55±1.20) μm, (12.74±1.57) μm, and (70.67±4.40) μm, respectively. The total length of spermatozoa in estuarine crocodile was measured at (88.96±0.52) μm. The most common spermatozoa abnormalities found in the samples were cytoplasmic droplets. Conclusions: Normal morphology, morphometry of spermatozoa in estuarine crocodile which are vermiform shaped-head with a long tail along with questionably high cytoplasmic droplets count are described in this study.
文摘Time: a sunny day Place: a river in the forest Characters: Fox, Crocodile(鳄鱼) , Rabbit A, Rabbit B, Little Deer, Mother Deer Scene ⅠStoryteller: There are many animals in the forest. There is a river in the forest, too.When the animals are thirsty(口渴的) , they often drink water in the river. But there is a bad big crocodile living in the river too. All the small animals hate him but they are also afraid of him.
文摘In 1927, when René Lacoste chose the crocodile as his emblem, he had not imagined that 80 years later, millions of people would bear this logo. He could also not imagine that the crocodile would be
基金supported by the Graduate Reaearch and Innovation Projects of Jiangsu Province(KYCX21_2251).
文摘Crocodiles,one of the oldest and most resilient species on Earth,have demonstrated remarkable locomotor abilities both on land and in water,evolving over millennia to adapt to diverse environ-ments.In this study,we draw inspiration from crocodiles and design a highly biomimetic crocodile robot equipped with multiple degrees of freedom and articulated trunk joints.This design is based on comprehensive analysis of the structural and motion characteristics of real crocodiles.The bionic crocodile robot has a problem of limb-torso incoordination during movement.To solve this problem,we used the D-H method for both forward and inverse kinematics analysis of the robot's legs and spine.Through a series of simulation experiments,we investigated the robot's motion stability,fault tolerance,and adaptability to environments in two motor patterns:with and without spine and tail movements.The experimental results show that the bionic crocodile robot exhibits superior motion performance when the spine and tail cooperate with the extremities.This study not only demonstrates the potential of biomimicry in robotics but also underscores the significance of understanding how nature's designs can inform and enhance technological innovations.
基金supported by the Hong Kong Research Grants Council Grant ECS[24163117]GRF[14101119]+1 种基金National Natural Science Foundation of China[81970423]SKLA(CUHK).
文摘Cardiovascular disease is a major cause of mortality in diabetic patients due to the heightened oxidative stress and pro-inflammatory state in vascular tissues.Effective approaches targeting cardiovascular health for diabetic patients are urgently needed.Crocodile blood,an emerging dietary supplement,was suggested to have anti-oxidative and anti-inflammatory effects in vitro,which have yet to be proven in animal models.This study thereby aimed to evaluate whether crocodile blood can protect vascular function in diabetic mice against oxidation and inflammation.Diabetic db/db mice and their counterparts db/m+mice were treated daily with crocodile blood soluble fraction(CBSF)or vehicle via oral gavage for 4 weeks before their aortae were harvested for endothelium-dependent relaxation(EDR)quantification using wire myograph,which is a well-established functional study for vascular function indication.Organ culture experiments culturing mouse aortae from C57BL/6 J mice with or without IL-1βand CBSF were done to evaluate the direct effect of CBSF on endothelial function.Reactive oxygen species(ROS)levels in mouse aortae were assessed by dihydroethidium(DHE)staining with inflammatory markers in endothelial cells quantified by quantitative polymerase chain reaction(qPCR).CBSF significantly improved deteriorated EDR in db/db diabetic mice through both diet supplementation and direct culture,with suppression of ROS level in mouse aortae.CBSF also maintained EDR and reduced ROS levels in mouse aortae against the presence of pro-inflammatory IL-1β.Under the pro-inflammatory state induced by IL-1β,gene expressions of inflammatory cytokines were downregulated,while the protective transcripts UCP2 and SIRT6 were upregulated in endothelial cells.Our study suggests a novel beneficial effect of crocodile blood on vascular function in diabetic mice and that supplementation of diet with crocodile blood may act as a complementary approach to protect against vascular diseases through anti-oxidation and anti-inflammation in diabetic patients.
基金This work is financed by the grants of the National Natural Science Foundation of China （Grant No 40272084, 40472101 and 40572123）.
文摘The MohroCoulomb criterion has been widely used to explain formation of fractures. However, it fails to explain large strain deformation that widely occurs in nature. There is presently a new theory, the MEMC, which is mathematically expressed as Meff = （（σ1-σ3） L.sin 2α sin α）/2, where σ1-σ3 represents the yield strength of the related rock, L is a unit length and a is the angle between σ1 and deformation bands. This criterion demonstrates that the maximum value appears at angles of ±54.7° to σ1 and there is a slight difference in the moment in the range of 55°±10°. The range covers the whole observations available from nature and experiments. Its major implications include： （1） it can be used to determine the stress state when the related deformation features formed; （2） it provides a new approach to determine the Wk of the related ductile shear zone if only the ratio of the vorticity and strain rate remains fixed; （3） It can be used to explain （a） the obtuse angle in the contraction direction of conjugate kink-bands and extensional crenulation cleavages, （b） formation of low-angle normal faults and high-angle reverse faults, （c） lozenge ductile shear zones in basement terranes, （d） some crocodile structures in seismic profiles and （e） detachment folds in foreland basins.
基金The Ministry of Natural Resources and Environment,Malaysia provided financial support to the project。
文摘The diet of juvenile,including hatchlings and presumed yearlings of the Saltwater Crocodile,Crocodylus porosus,was studied at the Kuching Wetlands National Park,western Sarawak,East Malaysia(Borneo),using both frequency of occurrence and volumetric composition of diet through the stomach flushing technique.Crustaceans form the primary component of the diet of juvenile crocodiles,comprising shrimps of the family Atyidae(Caridina sp.,and Penaeus indicus),occurring in the stomach of 17 individuals(53%by occurrence).An estimated 91.7%of hatchlings stomach-flushed had shrimps,and the emergence of hatchlings may be associated by inland migration of its shellfish prey,as reported in the literature.The secondary food item of hatchlings and presumed yearlings was ocypodid crabs,occurring in 16 individuals(in addition to a subadult),and comprise 47%-50%by occurrence.Other items taken incidentally include rodents(in large yearlings,exceeding 100 cm in total length),and fish(in seven hatchlings and in one subadult),or in 29%of total individuals captured(47.7%in hatchlings and 15%in yearlings).A dietary change in ontogeny is therefore evident,as reported earlier in crocodilians.
基金The authors gratefully acknowledge the financial support of Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams under Grants No.2019KJ125the fund of Young Innovative Talents Project from Department of Education of Guangdong Province China(Grants No.2018KQNCX021).
文摘The resistance between mud surface and ship-type paddy field machine hull accounts for a certain proportion of the total mechanical power consumption during the operation process.The special characteristic has been found via preliminary study,it showed that when starting or working at low velocity,the resistance is much greater than the machine working at the rated velocity.This characteristic affects the dynamic matching and structural design of the machine.The critical velocity of resistance distortion was around 0.025 m/s under the setting experimental conditions,and the mechanism of resistance distortion under multi-medium was analyzed.Based on water film drag reduction theory,a macroscopic structure of crocodile's abdominal armor biomimetic drag reduction method was proposed.Two kinds of bionic macroscopic structure ship board were fabricated.The macroscopic structure can introduce more water into the bottom surface of the hull;thicken the water film,which can reduce the travel resistance.Design and manufacture a ship-type paddy field experimental setup with velocity control,and compare the traditional smooth surface ship board with the two bionic macroscopic structure surfaces through orthogonal test.The experiment results demonstrated that the ship board with rectangle gully structure has better drag reduction effect than the hexagon one in the lower velocity.But when the travel velocity approach to the resistance distortion critical point,the hexagon gully structure become better than the other one.Through the orthogonal test,the best drag reduction combination is 2.5 kg load weight,0.025 m/s travel velocity with hexagon ship board,which decreases the drag by 6.3%.
