Microstructure and mechanical property of turtle shell

The turtle shell is an amazing structure optimized through the long-term evolution by nature. This paper reports the experimental study on the mechanical property at different levels and locations, and the microstructure of the shell from Trachemys scripta （Red-ear turtle） living in South China.

3D Multilayered Turtle Shell Models for Image Steganography

By embedding secret data into cover images,image steganography can produce non-discriminable stego-images.The turtle shell model for data hiding is an excellent method that uses a reference matrix to make a good balance between image quality and embedding capacity.However,increasing the embedding capacity by extending the area of basic structures of the turtle shell model usually leads to severe degradation of image quality.In this research,we innovatively extend the basic structure of the turtle shell model into a three-dimensional(3D)space.Some intrinsic properties of the original turtle shell model are well preserved in the 3D version.Theoretic analysis shows that the new proposed models have good performance both in the image quality and in the complexity of the reference matrix.Our experimental results justify the theoretic conclusions.

Numerical Study of the Mechanical Response of Turtle Shell

The turtle shell is an amazing structure optimized through the long-term evolution by nature. This paper reports the me- chanical respor/se of the shell （Red-ear turtle） to static and dynamic loads, respectively. It is found that the turtle shell under a compressive load yields the maximum vertical displacement at the rear end, but the vertical displacement at the front end is only half of that at the rear end. The maximum horizontal displacement of the shell also occurs at the rear end. It is believed that such a deformation pattern is helpful for protecting the turtle＇s internal organs and its head. The principal stress directions in the inside surface of the shell under a compressive load are almost the same as those of the biofiber distribution in the inside surface, which results in the strong bending resistance of the turtle shell.

Measurements on the Turtle’s Shell that Help Illuminate How the Fishes Lateral Line Function Was Replaced by the Reptilian Hearing Organ

The acoustic sense of fish, embodied in the lateral line, no longer worked when amphibians ventured onto the land. The new acoustic environment where sound traveled in the thin medium of air rather than the relatively dense medium of water presented a major challenge. The multiple sensors of the lateral line were replaced by one gross sensor, the tympanic membrane or eardrum. We show acoustical measurements on the turtle shell that can suggest a possible explanation of how the turtle dealt with the issue of sensing the directionality of incoming sounds.

Intervention effect and mechanism of Jisheng Shenqi Decoction plus Panax notoginseng and Bionjia on CCl4-induced hepatic fibrosis rat model

Objective:To investigate the intervention effect and specific mechanism of Jisheng Shenqi Decoction plus Panax notoginseng and Turmeric on carbon tetrachloride(CCl4)-induced liver fibrosis in rats.Methods:SPF SD rats were randomly divided into control group,model group,and Chinese medicine treatment(low,medium and high dose)groups.The model group and Chinese medicine treatment group were given intraperitoneal injection of 40%CCl4 olive oil solution twice a week.A rat model of liver fibrosis was replicated by the method for 8 weeks.After successful modeling,each drug-administered group was gavaged with corresponding drugs,and the control group and model group were gavaged with equal volume of distilled water,once a day,for 4 weeks.After the last intragastric administration,HE staining and Masson staining were used to observe the pathological morphology of liver tissue,and liver function(ALT,AST)was detected;ELISA method was used to determine transforming growth factorβ(TGF-β),angiotensin II(Ang-Ⅱ),chitinase 3-like protein 1(CHI3L1),interleukin-1(IL-1),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α)content;The expression levels of type I,type III collagen(Col-Ⅰ,Col-Ⅲ)and TGF-βmRNA were determined by RT-PCR.Results:①HE and Masson staining showed that a large number of liver cells in the model group were inflamed and necrotic,the collagen fibers in the liver tissue were extensively proliferated,the fibrous septa were interconnected,and the pseudolobules were formed.Compared with the model group,the levels of ALT,AST,TGF-β,Ang-Ⅱ,CHI3L1,IL-1,IL-6 and TNF-αin the traditional Chinese medicine treatment group were decreased,while the levels of Col-Ⅰ,Col-ⅢThe expressions ofⅢand TGF-βmRNA were decreased,and the effect was most obvious in the middle and high dose groups of traditional Chinese medicine(P<0.01).Conclusion:Jisheng Shenqi Decoction combined with Panax notoginseng and Biejia can significantly improve liver fibrosis induced by CCl4 in rats,and its mechanism may be related to the down-regulation of angiotensin-converting enzyme(ACE)-angiotensin II(Ang-II)-angiotensin II receptor 1(AT1R)signaling pathway related gene expression,reducing the level of related cytokines,promoting the degradation of extracellular matrix and so on.