Turtle Shell Research Articles

Effect of Needle Type, Number of Layers on FPAFC Composite against Low-Velocity Projectile Impact

Protective structures subjected to intensive loads that may benefit from the use of multilayer composite structures with excellent hardness and impact resistance represent an emerging research field in recent times. In this study, low-velocity projectile impact tests were performed on Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) mixtures to evaluate their performance. The effects of projectile needle type, fibre type and hybridization in addition to the number of layers in the composites on projectile impact were investigated. The bioinspiration of the excellent impact strength of turtle shells was used to design an FPAFC comprising a higher amount of steel and polypropylene fibres at the outer layers. In parallel, one and two-layered concretes were also cast to assess the effectiveness of three-layered FPAFC. The tests were performed on disc specimens using non-deformable compound bevel, convex edge and hollow edge projectiles. The damage severity was quantified by the top damage area, bottom damage area and depth of penetration. In addition, a simple analytical model for predicting the composite mass expulsion was developed and implemented. Findings indicated that regardless of fiber type and distribution, the compound bevel projectile needle produced the lowest impact numbers for all single, double and triple-layer specimens compared to the convex edge and hollow edge projectiles. Repeated projectile impacts increased the penetration depth and damaged area at the top and bottom surfaces of all targets. Targets were more resistant to convex edge and hollow edge projectile penetration than the compound bevel. The experimental and analytical model results for mass expelled from the top surface are reasonably acceptable. This research gives an idea of developing advanced fibrous composite with superior impact resistance for the promising protective structures.

Impact Resistance of Functionally Layered Two-Stage Fibrous Concrete

The impact resistance of functionally layered two-stage fibrous concrete (FLTSFC) prepared using the cement grout injection technique was examined in this study. The impact resistance of turtle shells served as the inspiration for the development of FLTSFC. Steel and polypropylene fibres are used in more significant quantities than usual in the outer layers of FLTSFC, resulting in significantly improved impact resistance. An experiment was carried out simultaneously to assess the efficacy of one-layered and two-layered concrete to assess the effectiveness of three-layered FLTSFC. When performing the drop-mass test ACI 544, a modified version of the impact test was suggested to reduce the scattered results. Instead of a solid cylindrical specimen with no notch, a line-notched specimen was used instead. This improvement allows for the pre-definition of a fracture route and the reduction of the scattering of results. The testing criteria used in the experiments were impact numbers associated to first crack and failure, mode of failure, and ductility index. The coefficient of variation of the ACI impact test was lowered due to the proposed change, indicating that the scattering of results was substantially reduced. This research contributes to the idea of developing enhanced, more impact-resistant fibre composites for use in possible protective structures in the future.

Reparative regeneration of histogenetically different bones

The bone plates that forming the turtle shell differ in histogenesis. Thus, the costal and neural plates of the carapace (dorsal shield) have mesenchymal origin and develop by indirect perichondral osteogenesis from vertebrae and ribs. The bone plates of the plastron - abdominal shield, are known to be formed from neuroectodermal cells of the neural crest and develop by intramembrane osteogenesis in the dermis of the skin. The aim of the study was to compare the reparative regeneration of histogenetically different bone tissue of the carapace and plastron of freshwater red-eared turtles Trachemys scripta. The experiment was performed on freshwater red-eared turtles Trachemys scripta aged 3 months. 2 defects of carapace and plastron bone plates with a diameter of 5 mm and a depth of up to "soft tissues” were formed with further histological examination. It was found that the regeneration of the bone plates of the plastron is characterized by the formation of bone tissue in a larger volume and at an earlier date. After 30 days a layer of continuous newly formed bone tissue is formed. By 90 days the proportion of bone tissue in the carapace regenerate was 40,5% of the defect area, while in the plastron the regenerate occupied 47,4%. Thus, intramembranous formed bone tissue of neuroectodermal histogenesis has a more pronounced regenerative potential compared to perichondral formed bone of mesenchymal origin.

Effect of novel turtle shell decoction on cycle, apoptosis, CTGF/Itgα 5 pathway and expression of Col1a1 in rat hepatic stellate cells

Effect of novel turtle shell decoction on cycle, apoptosis, CTGF/Itgα 5 pathway and expression of Col1a1 in rat hepatic stellate cells

Foil tape—a simple, versatile tool for turtle shell repair

The repair of shell fractures in turtles is often delayed due to the time, labor and resources involved in many current shell repair methods, resulting in increased stress, handling and recovery time for the patient. This article introduces a new repair technique using aluminium foil tape combined with cyanoacrylate glue, which allows quick, simple and long-lasting closure of fresh shell injuries. Strips of malleable but inelastic foil tape are cut to size and positioned across the fracture at critical junctures, then glued in place on either side of the wound and burnished down to conform to surface irregularities and insure consistent adhesion. This technique is non-invasive, requires no curing time and can be customized for a wide range of turtle sizes and injuries, either as a stand-alone method or a preliminary stabilization tool. In the author’s experience, it has proven to be consistently effective at reducing fractures and staying in place until removal, when it is easily peeled off with no residual damage. The speed, ease and endurance of the foil tape method may encourage more widespread repair of fresh shell fractures and, in so doing, optimize recovery time and results for chelonian patients.

Global Analysis of Transcriptome and Translatome Revealed That Coordinated WNT and FGF Regulate the Carapacial Ridge Development of Chinese Soft-Shell Turtle.

The turtle carapace is composed of severely deformed fused dorsal vertebrae, ribs, and bone plates. In particular, the lateral growth in the superficial layer of turtle ribs in the dorsal trunk causes an encapsulation of the scapula and pelvis. The recent study suggested that the carapacial ridge (CR) is a new model of epithelial–mesenchymal transition which is essential for the arrangement of the ribs. Therefore, it is necessary to explore the regulatory mechanism of carapacial ridge development to analyze the formation of the turtle shell. However, the current understanding of the regulatory network underlying turtle carapacial ridge development is poor due to the lack of both systematic gene screening at different carapacial ridge development stages and gene function verification studies. In this study, we obtained genome-wide gene transcription and gene translation profiles using RNA sequencing and ribosome nascent-chain complex mRNA sequencing from carapacial ridge tissues of Chinese soft-shell turtle at different development stages. A correlation analysis of the transcriptome and translatome revealed that there were 129, 670, and 135 codifferentially expressed genes, including homodirection and opposite-direction differentially expressed genes, among three comparison groups, respectively. The pathway enrichment analysis of codifferentially expressed genes from the Kyoto Encyclopedia of Genes and Genomes showed dynamic changes in signaling pathways involved in carapacial ridge development. Especially, the results revealed that the Wnt signaling pathway and MAPK signaling pathway may play important roles in turtle carapacial ridge development. In addition, Wnt and Fgf were expressed during the carapacial ridge development. Furthermore, we discovered that Wnt5a regulated carapacial ridge development through the Wnt5a/JNK pathway. Therefore, our studies uncover that the morphogenesis of the turtle carapace might function through the co-operation between conserved WNT and FGF signaling pathways. Consequently, our findings revealed the dynamic signaling pathways acting on the carapacial ridge development of Chinese soft-shell turtle and provided new insights into uncover the molecular mechanism underlying turtle shell morphogenesis.

The excavation of a cache of lead ingots in Liujiazhuang Locus North of Yinxu, Anyang, Henan

Abstract In August 2015, an earthen cache pit of lead ingots was discovered to the northwest of Liujiazhuang Village within the Yinxu site. The round pit yielded an assemblage of 293 lead ingots weighed 3404kg. The ingots are shaped like turtle shells with broader fronts and narrower rears. Their full length measured from 10cm to 70cm. Lead was an important element in the bronze metallurgy of the Shang and Zhou dynasties. The excavation of the cache of lead ingots is significant to the studies of the scale, technology, organization, and management of the bronze-casting industry of the Shang dynasty.

Pharmacokinetics of Nebulized Terbinafine in Plasma and Keratin of Northwestern Pond Turtles (Actinemys marmorata) Associated with Emydomycosis

The Northwestern pond turtle ( Actinemys marmorata ) is native to Washington State, USA and has developed a grossly evident form of shell disease affecting a large percentage of the free-ranging population in this state. Emydomyces testavorans is a novel fungus in the order Onygenales that is the presumed causative agent for shell disease in the Northwestern pond turtle. Terbinafine hydrochloride is a lipophilic allylamine broad spectrum antifungal that penetrates keratin and concentrates in the stratum corneum. This study evaluated the drug concentration in the plasma and keratin of 18 Northwestern pond turtles after nebulization with 18 mg terbinafine solution (2 mg/ml) once a day for 28 days. Blood and keratin samples were collected serially during the course of treatment, and for 14 days following the last dose. Plasma and keratin were analyzed by high-performance liquid chromatography. No significant concentrations of terbinafine were found in the plasma of the turtles. Terbinafine in turtle keratin peaked after 16 days of treatment and maintained therapeutic concentrations for 14 days post treatment. Turtle shell lesions also showed signs of clinical improvement post-therapy. Nebulization of terbinafine is recommended for the treatment of shell disease secondary to Emydomyces testavorans , however pulse antifungal therapy is likely needed to prevent disease from reoccurring.

Ectoparasite borings, mesoparasite borings, and scavenging traces in early Miocene turtle and tortoise shell: Moghra Formation, Wadi Moghra, Egypt

AbstractBorings and bite marks on fossil turtle carapaces and plastra from the Miocene Moghra Formation, northern Egypt, are herein described. All fossil turtle material from Moghra exhibits ichnofossils. The positions of invertebrate borings on external surfaces of tortoise and turtle shell material at Moghra are consistent with the activities of ectoparasites or mesoparasites.A single invertebrate ichnotaxon, Karethraichnus lakkos Zonneveld et al., 2016, occurs on Moghra tortoise fossils. This trace fossil was likely emplaced by ixodid arthropods (ticks). Bite marks assigned to Nihilichnus occur on a carapace peripheral and are interpreted to reflect postmortem scavenging. An abundant and moderately diverse assemblage of invertebrate borings characterizes Moghra aquatic turtle shells. Karethraichnus lakkos and Thatchtelithichnus holmani Zonneveld et al., 2016 traces on aquatic turtles are interpreted to reflect leech and/or trematode parasitism. Gunnellichnus moghraensis (new ichnogenus new ichnospecies) and G. akolouthiste (n. isp.) likely reflect bacterial and/or fungal infections on aquatic turtle shells that rarely dried out.UUID: http://zoobank.org/f0a3977d-deff-4954-b196-536adc405854

Turtle Shell Disease Fungus (Emydomyces testavorans): First Documented Occurrence in California and Prevalence in Free-Living Turtles

Pond Turtle Shell Disease is an emerging infectious disease associated with the fungus Emydomyces testavorans (Emte). Here, we report the first documented case of Emte in free-ranging Californian turtles. We assayed Emte in nine Western Pond Turtles (Emys = Actinemys marmorata; WPT) and three non-native Red-eared Slider turtles (Trachemys scripta elegans; RES) from the same pond in Santa Cruz County, California. Despite several WPT exhibiting significant shell lesions, scute defects, and pliable scutes, all tested negative for Emte. However, all three RES were Emte-positive, although two of these showed no shell defects. Given all tested RES were Emte-positive, it is possible that some WPT results are false negatives, either due to assay performance or insufficient shell tissue sampling. However, our Emte results in WPT are likely true negatives, and thus our observations contrast the high prevalence of Emte and shell disease in WPT from Washington. The emergence of Emte in California poses a previously unaccounted conservation concern for imperiled WPT. Emte's presence in California is also an important opportunity to study the epidemiology and ecology of this pathogen in a contrasting environmental context to Washington state where shell disease has had pronounced conservation consequences. Given the recent discovery of Snake Fungal Disease in California and the substantial impact the amphibian chytrid fungus has had on California's amphibians, there is an urgent need to understand the spread, prevalence, and impacts of Emte and other emerging wildlife diseases in California and elsewhere.

EVALUATION OF IMMUNE FUNCTION IN TWO POPULATIONS OF GREEN SEA TURTLES (CHELONIA MYDAS) IN A DEGRADED VERSUS A NONDEGRADED HABITAT.

There is a strong correlation between degraded marine habitats and the prevalence of diseases such as green turtle fibropapillomatosis (GTFP) in coastal populations. In GTFP, small to large tumors grow on the turtle's soft tissues and shell, while internal nodules may also occur. The disease primarily affects juvenile green sea turtles (Chelonia mydas) that reside in nearshore waters. As a link has been shown between environmental pollution and immune suppression in a variety of animals, the objective of our research was to compare innate and adaptive immune responsiveness in green sea turtles from a severely degraded and a more pristine habitat, which differ greatly in rates of GTFP. We quantified phagocytosis by flow cytometry and performed in vitro stimulation analysis to measure activity of both the innate and adaptive immune systems in wild-caught Florida green turtles. Sea turtles from the degraded environment, both with and without visible cutaneous tumors, exhibited significantly reduced phagocytosis and stimulation indices than did those from the less polluted environment. Our results suggest that environmental factors may contribute to the development of GTFP and thus can impact the health of sea turtle populations.

Modified Falling Mass Impact Test Performance on Functionally Graded Two Stage Aggregate Fibrous Concrete.

This research examined the performance of functionally graded two-stage fibrous concrete (FTSFC) against modified repeated falling-mass impacts. This study led to the concept of creating improved multiphysics model of fibre composites with better impact resistance for potential protective constructions. FTSFC was developed based on the bio-inspiring strength of turtle shells. The excellent impact resistance of FTSFC was accomplished by including a larger quantity of steel and polypropylene fibres in the outer layers. At the same time, one- and two-layered concrete were cast and compared to evaluate the efficiency of three-layered FTSFC. To minimize the dispersed test results, a modified form of the 544 drop-mass impact test was recommended by the American Concrete Institute (ACI). The modification was a knife-edge notched specimen instead of a solid cylindrical specimen without a notch. This modification predefined a crack path and reduced the dispersion of results. Cracking and failure impact numbers, ductility index, and failure mode were the testing criteria. The suggested modification to the ACI impact test decreased the coefficient of variance, showing that the dispersion of test results was reduced significantly. This study led to the concept of creating improved, fibre composites with better impact resistance for potential protective constructions.

Hiding data in dual images based on turtle shell matrix with high embedding capacity and reversibility

Hiding data in dual images based on turtle shell matrix with high embedding capacity and reversibility

Reduction, reorganization and stasis in the evolution of turtle shell elements

Abstract Novel phenotypic configurations can profoundly alter the evolutionary trajectories of species. Although innovation can precede lengthy periods of evolutionary stasis, the potential for species to diversify further can be realized via modular changes across distinct levels of hierarchical organization. To test this expectation, we undertook anatomical network analyses to model the organization and composition of the turtle’s shell. Our results suggest that stem turtles featured the greatest diversity in the number of skeletal (bones) and epidermal (scutes) shell elements. The shell subsequently underwent numerical simplification. Thus, the sum of potential connections (links) in shell networks has diminished in modern turtles. Some network system descriptors of complexity, integration and modularity covaried with the number of network components (nodes), which has remained evolutionarily stable since the Jurassic. We also demonstrated that shell reorganization might be feasible within modular subdivisions, particularly in modern turtles with simplified and less integrated network structures. We discuss how these findings align with previous studies on numerical simplification with enhanced skeletal specialization in the tetrapod skull. Altogether, our analyses expose the evolvability of the turtle’s shell and bolster the foundation for further macroevolutionary comparisons of ancient and modern species.

Production of Biodiesel from a Novel Combination of Raphia Africana Kernel Oil and Turtle Shell (Centrochelys Sulcata) Heterogenous Catalyst

This work investigated the viability of a non-edible oil obtained from raphia africana in the production of biodiesel using a novel heterogeneous catalyst derived from turtle shells (Centrochelys sulcata). The study also proposed the use of acetone as co-solvent to enhance the solubility of the reacting mixtures. The turtle shells were calcined at 900oC for 3hr, impregnated in KOH to improve its activity and then supported with activated carbon produced from cassava peels to increase its surface area. The influences of KOH concentration, catalyst loading, catalyst/carbon mix ratio and concentration of acetone/methanol on the yield of biodiesel were investigated. The results obtained revealed that maximum biodiesel yield of 93% was obtained from the bio-oil at KOH concentration of 30% (w/w), catalyst loading of 6.5%, solvent/methanol ratio of 0.4 and catalyst/carbon weight ratio of 1.25. The activated carbon supported turtle shell catalyst has been found to possess very high catalytic activity converting bio-oil with high saturated fatty acid content to biodiesel with excellent fuel properties having low saturated fatty acids profile. Doi: 10.28991/HEF-2021-02-03-07 Full Text: PDF

Multi-parametric optimization of the catalytic pyrolysis of pig hair into bio-oil

AbstractThe low yield and poor fuel properties of bio-oil have made the pyrolysis production process uneconomic and also limited bio-oil usage. Proper manipulation of key pyrolysis variables is paramount in order to produce high-quality bio-oil that requires less upgrading. In this research, the pyrolysis of pig hair was carried out in a fixed-bed reactor using a calcium oxide catalyst derived from calcination of turtle shells. In the pyrolysis process, the influence of three variables—temperature, heating rate and catalyst weight—on two responses—bio-oil yield and its higher heating value (HHV)—were investigated using Response Surface Methodology. A second-order regression-model equation was obtained for each response. The optimum yield of the bio-oil and its HHV were obtained as 51.03% and 21.87 mJ/kg, respectively, at 545oC, 45.17oC/min and 2.504 g of pyrolysis temperature, heating rate and catalyst weight, respectively. The high R2 values of 0.9859 and 0.9527, respectively, obtained for the bio-oil yield and its HHV models using analysis of variance revealed that the models can adequately predict the bio-oil yield and its HHV from the pyrolysis process.

A Systems Approach of Topology Optimization for Bioinspired Material Structures Design Using Additive Manufacturing

Bioinspired design has been applied in sustainable design (e.g., lightweight structures) to learn from nature and support material structure functionalities. Natural structures usually require modification in practice because they were evolved in natural environmental conditions that can be different from industrial applications. Topology optimization is a method to find the optimal design solution by considering the material external physical environment. Therefore, integrating topology optimization into bioinspired design can benefit sustainable material structure designers in meeting the purpose of using bioinspired concepts to find the optimal solution in the material functional environment. Current research in both sustainable design and materials science, however, has not led to a method to assist material structure designers to design structures with bioinspired concepts and use topology optimization to find the optimal solution. Systems thinking can seamlessly fill this gap and provide a systemic methodology to achieve this goal. The objective of this research is to develop a systems approach that incorporates topology optimization into bioinspired design, and simultaneously takes into consideration additive manufacturing processing conditions to ensure the material structure functionality. The method is demonstrated with three lightweight material structure designs: spiderweb, turtle shell, and maze. Environmental impact assessment and finite element analysis were conducted to evaluate the functionality and emissions of the designs. This research contributes to the sustainable design knowledge by providing an innovative systems thinking-based bioinspired design of material structures. In addition, the research results enhance materials knowledge with an understanding of mechanical properties of three material structures: turtle shell, spiderweb, and maze. This research systemically connects four disciplines, including bioinspired design, manufacturing, systems thinking, and lightweight structure materials.

How many trees to see the forest? Assessing the effects of morphospace coverage and sample size in performance surface analysis

Abstract Linking morphology and function is critical to understanding the evolution of organismal shape. Performance landscapes, or performance surfaces, associate empirical functional performance data with a morphospace to assess how shape variation relates to functional variation. Performance surfaces for multiple functions also can be combined to understand the functional trade‐offs that affect the morphology of a particular structure across species. However, morphological performance surfaces usually require empirical determination of performance for a number of theoretical shapes that are evenly distributed throughout the morphospace. This process is time‐consuming, and is problematic for structures that are difficult to precisely manipulate. We sought to (a) understand the degree and pattern of sampling required to produce a reliable and nuanced performance surface and (b) investigate the possibility of building a surface using only naturally occurring morphologies. To do this, we subsampled a pre‐existing set of turtle shell performance surfaces in four different ways: first, uniform subsampling of theoretical morphologies across the surface; second, random subsampling of theoretical morphologies across the surface; third, a combination uniform/random subsampling method called close‐pairs sampling and fourth, subsampling only points on the surface known to correspond to a naturally occurring turtle shell morphology. Each subset was interpolated with ordinary Kriging to produce a new performance surface for comparison to the original. We found that using a fraction of the theoretical morphologies examined in the original study (half as many or fewer) was sufficient to produce a performance surface bearing close resemblance to the original (Pearson correlation ≥0.90); close‐pairs sampling dramatically increased the power of small sample sizes. We also discovered that only sampling points on the surface corresponding to naturally occurring morphologies produced an accurate surface, but results were better when individual specimens, rather than species averages, were used. Our findings demonstrate the viability of using performance surfaces to understand the evolution of complex morphologies for which theoretical shape modelling is difficult or computationally burdensome. Both lower levels of carefully configured sampling throughout the theoretical morphospace, and development of performance surfaces using only data from naturally occurring morphologies, are acceptable alternatives to the dense theoretical shape sampling employed in previous studies. ​

Improving the activity and stability of turtle shell-derived catalyst in alcoholysis of degraded vegetable oil: An experimental design approach

In the activation of a heterogeneous catalyst, manipulating certain variables can affect its morphology, active sites and porosity which determine the efficiency of a heterogeneous catalyst. In this work, a highly efficient heterogeneous catalyst was synthesized from a waste turtle shell, which is a novel waste material. Using the experimental design, the influence of three parameters: calcination temperature, calcination time and KOH loading on the catalyst efficiency was studied. The catalyst efficiency was measured by taking the average biodiesel yields in four re-use cycles. Among others, an optimum catalyst efficiency of 81.2% was obtained at a calcination temperature of 807 °C, calcination time of 196mins and KOH loading of 33%(w/w). The obtained Catalyst was very efficient since it possessed high catalytic property, including activity and selectivity, even after being used in four transesterification reactions.

271 Sleep staging performance of a signal-agnostic cloud-based real-time sleep analytics platform

IntroductionThe coronavirus pandemic has brought unprecedented changes to the health care system, including sleep medicine. Remote monitoring and telemedicine played a significant role in this shift. We anticipate these changes to continue in the future with internet-connected wearables (ICWs) playing an important role in measuring and managing sleep remotely. As these ICWs measures a small subset of signals traditionally measured during polysomnography (PSG), manual sleep staging becomes non-trivial and sometimes impossible. The ability to do accurate and reliable automatic sleep staging using different modalities of physiological signals remotely is becoming ever more important.MethodsThe current work seeks to quantify the sleep staging performance of Z3Score-Neo (https://z3score.com, Neurobit Technologies, Singapore), a signal agnostic, cloud-based real-time sleep analytics platform. We tested its staging performance on the CINC open dataset with N=994 subjects using various combinations of signals including Electroencephalogram (EEG), Electrooculogram (EOG), Electromyogram (EMG), and Instantaneous Heart Rate (IHR) derived from Electrocardiogram (ECG). The staging was compared against manual scoring based on PSG. For IHR based staging, N1 and N2 were combined.ResultsWe achieved substantial agreement (all Cohen’s Kappa > 0.7) between automatic and manual staging using various combinations of EEG, EOG and EMG channels with accuracies varying between 81.76% (two central EEGs, one EOG, one EMG), 79.31% (EEG+EOG), 78.73% (EEG only) and 78.09% (one EOG). We achieved moderate agreement (accuracy: 72.8% κ=0.54) with IHR derived from ECG.ConclusionOur results demonstrated the accuracy of a cloud-based sleep analytics platform on an open dataset, using various combinations of ecologically valid physiological signals. EOG and EMG channels can be easily self-administered using sticker-based electrodes and can be added to existing home sleep apnea test (HSAT) kits significantly improving their utility. ICWs are already capable of accurately measuring EEG/EOG (Muse, InteraXon Inc., Toronto, Canada; Dreem band, Dreem, USA) and IHR derived from ECG (Movesense, Suunto, Finland) or photoplethysmogram (Oura Ring, Oura Health Oy, Finland) or through non-contact ballistocardiogram/radio-based measurements (Dozee, Turtle Shell Technologies, India; Sleepiz, Sleepiz AG, Switzerland). Therefore, a well-validated cloud-based staging platform solves a major technological hurdle towards the proliferation of remote monitoring and telehealth in sleep medicine.Support (if any):