Find research datasets worth reusing

Data from: How the online social networks are used: dialogs-based structure of MySpace

Quantitative study of collective dynamics in online social networks is a new challenge based on the abundance of empirical data. Conclusions, however, may depend on factors such as user's psychology profiles and their reasons to use the online contacts. In this study, we have compiled and analysed two datasets from MySpace. The data contain networked dialogues occurring within a specified time depth, high temporal resolution and texts of messages, in which the emotion valence is assessed by using the SentiStrength classifier. Performing a comprehensive analysis, we obtain three groups of results: dynamic topology of the dialogues-based networks have a characteristic structure with Zipf's distribution of communities, low link reciprocity and disassortative correlations. Overlaps supporting 'weak-ties' hypothesis are found to follow the laws recently conjectured for online games. Long-range temporal correlations and persistent fluctuations occur in the time series of messages carrying positive (negative) emotion; patterns of user communications have dominant positive emotion (attractiveness) and strong impact of circadian cycles and interactivity times longer than 1 day. Taken together, these results give a new insight into the functioning of online social networks and unveil the importance of the amount of information and emotion that is communicated along the social links. All data used in this study are fully anonymized.

Data from: Network structure and local adaptation in coevolving bacteria-phage interactions

Numerous theoretical and experimental studies have investigated antagonistic coevolution between parasites and their hosts. Although experimental tests of theory from a range of biological systems are largely concordant regarding the influence of several driving processes, we know little as to how mechanisms acting at the smallest scales (individual molecular and phenotypic changes) may result in the emergence of structures at larger scales, such as coevolutionary dynamics and local adaptation. We capitalized on methods commonly employed in community ecology to quantify how the structure of community interaction matrices, so called 'bipartite networks', reflected observed coevolutionary dynamics, and how phages from these communities may or may not have adapted locally to their bacterial hosts. We found a consistent nested network structure for two phage types, one previously demonstrated to exhibit arms race coevolutionary dynamics and the other fluctuating coevolutionary dynamics. Both phages increased their host ranges through evolutionary time, but we found no evidence for a trade off with impact on bacteria. Finally, only bacteria from the arms race phage showed local adaptation, and we provide preliminary evidence that these bacteria underwent (sometimes different) molecular changes in the wzy gene associated with the LPS receptor, while bacteria coevolving with the fluctuating selection phage did not show local adaptation and had partial deletions of the pilF gene associated with Type IV pili. We conclude that the structure of phage-bacteria interaction networks is not necessarily specific to coevolutionary dynamics, and discuss hypotheses for why only one of the two phages was, nevertheless, locally adapted.

opencc-zeroDec 2019View details →

Data from: Seed germination schedule and environmental context shaped the population genetic structure of subtropical evergreen oaks on the Yun-Gui Plateau, Southwest China

The evergreen broadleaved forests (EBLFs) of Southwest China have a long-term stable environment and support a diverse flora, thus forming a global biodiversity hotspot. However, the key drivers that have shaped the genetic diversity patterns of species in these EBLFs are not well understood. Quercus delavayi, Q. schottkyana, and Q. kerrii are sympatric oak species with different seed biological traits that are typical for these EBLFs. This study combined multilocus phylogeography and ecological niche modeling to screen 33 Q. delavayi populations. Their population genetic structure was inferred in comparison with previous studies on Q. schottkyana and Q. kerrii. The seed germination traits of all three species were also investigated. cpDNAs showed a significant phylogeographic structure in Q. delavayi, which was not detected in Q. schottkyana or Q. kerrii. Quercus delavayi, Q. kerrii, and Q. schottkyana exhibited different pollen-to-seed migration ratios (r = 219, 117, and 22, respectively), which are linked to the germination schedules of acorns. The distributions of Q. delavayi and Q. schottkyana remained long-term stable since the last glacial maximum (LGM) with a similar nSSR genetic gradient change along latitude. Instead, Q. kerrii experienced a prominent range expansion since the LGM with genetic diversification between the East and the West of the Tanaka line due to environmental heterogeneity. These results identify seed traits and environmental heterogeneity as two key drivers that shape the population genetic structure of EBLF trees in Southwest China. These should be considered in regional forestry conservation and management.

Data from: Ultra structural changes occurring in duct ectasia and periductal mastitits and their significance in etiopathogenesis

Introduction: Duct Ectasia (DE) and Periductal Mastitis (PDM) are the most common benign breast conditions seen in women. The etiopathogenesis of these entities is still not clear and most of the theories regarding the causation are based on the histological features as seen on light microscopy. The ultramicroscopic features associated with these conditions that may give more insight to the etiopathogenesis are unknown. Aim: To study the ultrastructural changes occurring in mammary duct cones in patients with DE and PDM using Transmission Electron Microscopic (TEM). Method: Major ducts removed by radical duct excision from 21 patients with final histopathological diagnosis of DE and PDM were subjected to TEM study with 2 normal duct samples as controls Results: The TEM features of DE were denudation of the epithelial cells with focal loss of microvilli, widening of the inter-epithelial junctions with focal disruption of the T bars, periductal collagenisation without inflammation; and features suggestive of Epithelial Mesenchymal Transition (EMT). PDM features are intact epithelial lining with proliferative epithelium and periductal collagenisation with inflammation. Conclusions: Based on the TEM findings, we suggest that DE and PDM are two different entities. EMT is a novel finding observed in DE in this study.

Data from: A structural approach for understanding multispecies coexistence

Although observations of species-rich communities have long served as a primary motivation for research on the coexistence of competitors, the majority of our empirical and theoretical understanding comes from two-species systems. How much of the coexistence observed in species rich communities results from indirect effects among competitors that only emerge in diverse systems remains poorly understood. Resolving this issue requires simple, scalable, and intuitive metrics for quantifying the conditions for coexistence in multispecies systems, and how these conditions differ from those expected based solely on pairwise interactions. To achieve these aims, we develop a structural approach for studying the set of parameter values compatible with n-species coexistence given the geometric constraints imposed by the the matrix of competition coefficients. We derive novel mathematical metrics analogous to stabilizing niche differences and fitness differences that measure the range of conditions compatible with multispecies coexistence, incorporating the effects of indirect interactions emerging in diverse systems. We show how our measures can be used to quantify the extent to which the conditions for coexistence in multispecies systems differ from those that allow pairwise coexistence, and apply the method to a field system of annual plants. We conclude by presenting new challenges and empirical opportunities emerging from our structural metrics of multispecies coexistence.

Data from: Linking topological structure and dynamics in ecological networks

Interaction networks are basic descriptions of ecological communities and are at the core of community dynamics models. Knowledge of their structure should enable us to understand dynamical properties of ecological communities. However, the relationships between dynamical properties of communities and qualitative descriptors of network structure remain unclear. To improve our understanding of such relationships, we develop a framework based on the concept of strongly connected components, which are key structural components of networks necessary to explain stability properties such as persistence and robustness. We illustrate this framework for the analysis of qualitative empirical food webs and plant-plant interaction networks. Both types of networks exhibit high persistence (on average, 99% and 80% of species, respectively, are expected to persist) and robustness (only 0.2% and 2% of species are expected to disappear following the extinction of a species). Each of the networks is structured as a large group of interconnected species accompanied by much smaller groups that most often consist of a single species. This low-modularity configuration can be explained by a negative modularity-stability relationship. Our results suggest that ecological communities are not typically structured in multispecies compartments and that compartmentalization decreases robustness.

Data from: Global lack of flyway structure in a cosmopolitan bird revealed by a genome wide survey of single nucleotide polymorphisms

Knowledge about population structure and connectivity of waterfowl species, especially mallards (Anas platyrhynchos), is a priority due to recent outbreaks of Avian Influenza. Ringing studies that trace large-scale movement patterns have to date been unable to detect clearly delineated mallard populations. We employed 363 single nucleotide polymorphism (SNP) markers in combination with population genetics and phylogeographic approaches to conduct a population genomic test of panmixia in 801 mallards from 45 locations world-wide. Basic population genetic and phylogenetic methods suggest no or very little population structure on continental scales. Nor could individual-based structuring algorithms discern geographical structuring. Model-based coalescent analyses for testing models of population structure pointed to strong genetic connectivity among the world's mallard population. These diverse approaches all support the conclusion that there is a lack of clear population structure, suggesting that the world's mallards, perhaps with minor exceptions, form a single large, mainly interbreeding population.

Data from: Do genetic structure and landscape heterogeneity impact color morph frequency in a polymorphic salamander?

Landscape heterogeneity plays an important role in population structure and divergence, particularly for species with limited vagility. Here, we used a landscape genetic approach to identify how landscape and environmental variables affect genetic structure and color morph frequency in a polymorphic salamander. The Eastern Red-backed Salamander, Plethodon cinereus, is widely distributed in northeastern North America and contains two common color morphs, striped and unstriped, that are divergent in ecology, behavior, and physiology. To quantify population structure, rates of gene flow, and genetic drift, we amplified 10 microsatellite loci from 648 individuals across 28 sampling localities. This study was conducted in northern Ohio, where populations of P. cinereus exhibit an unusually wide range of morph frequency variation. To test whether genetic distance was more correlated with morph frequency, elevation, canopy cover, waterways, ecological niche, or geographic distance, we used resistance distance and least cost path analyses. We then examined whether landscape and environmental variables, genetic distance, or geographic distance were correlated with variation in morph frequency. Tests for population structure revealed three genetic clusters across our sampling range, with one cluster monomorphic for the striped morph. Rates of gene flow and genetic drift were low to moderate across sites. Genetic distance was most correlated with ecological niche, elevation, and a combination of landscape and environmental variables. In contrast, morph frequency variation was correlated with waterways and geographic distance. Thus, our results suggest that selection is also an important evolutionary force across our sites, and a balance between gene flow, genetic drift, and selection interact to maintain the two color morphs.

opencc-zeroDec 2007View details →

Data from: Compensatory evolution in RNA secondary structures increases substitution rate variation among sites

There is growing evidence that interactions between biological molecules (e.g., RNA-RNA, protein-protein, RNA-protein) place limits on the rate and trajectory of molecular evolution. Here, by extending Kimura's model of compensatory evolution at interacting sites, we show that the ratio of transition to transversion substitutions (κ) at interacting sites should be equal to the square of the ratio at independent sites. Because transition mutations generally occur at a higher rate than transversions, the model predicts that κ should be higher at interacting sites than at independent sites. We tested this prediction in 10 RNA secondary structures by comparing phylogenetically derived estimates of κ in paired sites within stems (κ(p)) and unpaired sites within loops (κ(u)). Eight of the 10 structures showed an excellent match to the quantitative predictions of the model, and 9 of the 10 structures matched the qualitative prediction κ(p) > κ(u). Only the Rev response element from the human immunovirus (HIV) genome showed the reverse pattern, with κ(p) < κ(u). Although a variety of evolutionary forces could produce quantitative deviations from the model predictions, the reversal in magnitude of κ(p) and κ(u) could be achieved only by violating the model assumption that the underlying transition (or transversion) mutation rates were identical in paired and unpaired regions of the molecule. We explore the ability of the APOBEC3 enzymes, host defense mechanisms against retroviruses, which induce transition mutations preferentially in single-stranded regions of the HIV genome, to explain this exception to the rule. Taken as a whole, our findings suggest that kappa may have utility as a simple diagnostic to evaluate proposed secondary structures.

Data from: Influences of past climatic changes on historical population structure and demography of a cosmopolitan marine predator, the common dolphin (genus Delphinus)

Climatic oscillations during the Pleistocene have greatly influenced the distribution and connectivity of many organisms, leading to extinctions but also generating biodiversity. While the effects of such changes have been extensively studied in the terrestrial environment, studies focusing on the marine realm are still scarce. Here we used sequence data from one mitochondrial and five nuclear loci to assess the potential influence of Pleistocene climatic changes on the phylogeography and demographic history of a cosmopolitan marine predator, the common dolphin (genus Delphinus). Population samples representing the three major morphotypes of Delphinus were obtained from ten oceanic regions. Our results suggest that short-beaked common dolphins are likely to have originated in the eastern Indo-Pacific Ocean during the Pleistocene and expanded into the Atlantic Ocean through the Indian Ocean. On the other hand, long-beaked common dolphins appear to have evolved more recently and independently in several oceans. Our results also suggest that short-beaked common dolphins had recurrent demographic expansions concomitant with changes in sea surface temperature during the Pleistocene and its associated increases in resource availability, which differed between the North Atlantic and Pacific Ocean basins. By proposing how past environmental changes had an effect on the demography and speciation of a widely distributed marine mammal, we highlight the impacts that climate change may have on the distribution and abundance of marine predators and its ecological consequences for marine ecosystems.

opencc-zeroDec 2012View details →

Data from: Microsatellite analysis of genetic diversity and population structure of Arabian horse populations

The Arabian horse ignites imagination throughout the world. Populations of this breed exist in many countries, and recent genetic work has examined the diversity and ancestry of a few of these populations in isolation. Here we explore seven different populations of Arabians represented by 682 horses. Three of these are Middle Eastern populations from near the historical origin of the breed, including Syrian, Persian, and Saudi Arabian. The remaining Western populations are found in Europe (the Shagya-Arabian and Polish-Arabian) and America (American-Arabian). Analysis of genetic structure was carried out using 15 microsatellite loci. Genetic distances, AMOVA, factorial correspondence analysis and a Bayesian method were applied. The results consistently show higher level of diversity within the Middle Eastern populations than the Western populations. The Western Arabian populations were the main source of among populations variation. Genetic differentiation was not strong among all Middle Eastern populations, but all American-Arabians showed differentiation from Middle Eastern populations and were somewhat uniform among themselves. Here, we explore the diversities of many different populations of Arabian horses, and find that populations not from the Middle East have noticeably lower levels of diversity, which may adversely affect the health of these populations.

Data from: Minor allele frequency thresholds strongly affect population structure inference with genomic datasets

One common method of minimizing errors in large DNA sequence datasets is to drop variable sites with a minor allele frequency below some specified threshold. Though widespread, this procedure has the potential to alter downstream population genetic inferences and has received relatively little rigorous analysis. Here we use simulations and an empirical SNP dataset to demonstrate the impacts of minor allele frequency (MAF) thresholds on inference of population structure. We find that model-based inference of population structure is confounded when singletons are included in the alignment, and that both model-based and multivariate analyses infer less distinct clusters when more stringent MAF cutoffs are applied. We propose that this behavior is caused by the combination of a drop in the total size of the data matrix and by correlations between allele frequencies and mutational age. We recommend a set of best practices for applying MAF filters in studies seeking to describe population structure with genomic data.

opencc-zeroDec 2014View details →

Data from: Unravelling the role of allochthonous aquatic resources to food web structure in a tropical riparian forest

1. The role of matter and energy flow across ecosystem boundaries for subsidized consumer populations is well known. However, little is known on the effects of allochthonous subsidies on food web structure and trophic niche dimensions of consumers in the tropics. 2. We excluded allochthonous aquatic insects from tropical streams using greenhouse-type exclosures to test the influence of aquatic allochthonous subsidies on the trophic structure and niche dimensions of terrestrial predators using stable isotope methods. 3. In exclosure treatments, abundance and biomass of terrestrial predators, and biomass of phytophages, decreased and increased, respectively. Vegetation-living predators were more responsive to allochthonous inputs than those living on the ground. Overall, lower availability of allochthonous inputs did not affect community-wide metrics and niche width of predators. However, the niche width of some spider families had very low overlap between treatments, and others had wider isotopic niches in the control than exclusion treatment. Most of the C and N in predators living in control stretches came from aquatic subsidies, and those predators living in exclusion treatments switched their diets to terrestrial sources, showing a preference of predators for allochthonous subsidies. 4. Our results suggest that allochthonous subsidies are also relevant to tropical fauna living upon vegetation. Moreover, allochthonous resources may amplify the niche dimension of certain predators, or considerably change the trophic niche of others. Our study highlights the importance of including modern isotopic tools in elucidating the role of allochthonous resources on the patterns of trophic structure and niche dimensions of consumers from donor ecosystems.

Data from: Selection on structural allelic variation biases plasticity estimates

Wang and Althoff (2019) explored the capacity of Drosophila melanogaster to exhibit adaptive plasticity in a novel environment. In a full-sib, half-sib design, they scored the activity of the enzyme alcohol dehydrogenase (ADH) and plastic responses, measured as changes in ADH activity across ethanol concentrations in the range of 0-10% (natural variation) and 16% (the novel environment). ADH activity increased with alcohol concentration, and there was a positive association between larval viability and ADH activity in the novel environment. They also reported that families exhibiting greater plasticity had higher larval survival in the novel environment, concluding that ADH plasticity is adaptive. However, the four authors now concur that, since the study estimated plasticity from phenotypic differences across environments using full-sib families, it is not possible to disentangle the contributions of allele frequency changes at the Adh locus from regulatory control at loci known to influence ADH activity. Selective changes in allele frequencies may thus conflate estimates of plasticity; any type of "plasticity" (adaptive, neutral, or maladaptive) could be inferred depending on allele frequencies. The problem of scoring sib-groups after selection should be considered in any plasticity study that cannot use replicated genotypes. Researchers should monitor changes in allele frequencies as one mechanism to deal with this issue.

Data from: Population assignment reveals low migratory connectivity in a weakly structured songbird

Understanding migratory connectivity is essential for determining the drivers behind population dynamics and for implementing effective conservation strategies for migratory species. Genetic markers provide a means to describe migratory connectivity, however they can be uninformative for species with weak population genetic structure, which has limited their application. Here, we demonstrated a genomic approach to describing migratory connectivity in the prothonotary warbler, Protonotaria citrea, a Neotropical songbird of conservation concern. Using 26,189 SNPs, we revealed regional genetic structure between the Mississippi River Valley and the Atlantic Seaboard with overall weak genetic differentiation among populations (FST = 0.0055; 95% CI: 0.0051 - 0.0059). Genetic variation had a stronger association with geographic rather than environmental factors, with each explaining 14.5% and 8.2% of genetic variation, respectively. By varying the numbers of genomic markers used in population assignment models with individuals of known provenance, we identified a maximum assignment accuracy (89.7% to site, 94.3% to region) using a subset of 600 highly differentiated SNPs. We then assigned samples from nonbreeding sites to breeding region, and found low migratory connectivity. Our results highlight the importance of filtering markers for informative loci in models of population assignment. Quantifying migratory connectivity for weakly structured species will be useful for expanding studies to a wider-range of migratory species across taxonomic groups and may contribute to a deeper understanding of the evolution of migratory strategies.

Data from: Parasites structuring ecological communities: the mistletoe footprint in Mediterranean pine forests

1. The capacity of parasitic plants in structuring natural communities is increasingly recognized. These plants can affect the structure, composition and productivity of plant communities by modifying the competitive balance between hosts and non-host species and by altering the quantity and quality of resources entering the soil. Despite the progress made in this field, there is still a lack of integrative studies showing the structuring capacity of parasitic plants in forest ecosystems, where their effect may be less detectable due to the long lifespan of the system. 2. In this study we evaluate the long-term impact of Viscum album subsp. austriacum on the woody-plant community of a Mediterranean pineland. This mistletoe remains several years on the same host, exerting long-lasting, spatially concentrated effects on community and ecosystem characteristics. Mistletoe concentrates zoochorous seeds and induces changes in the soil fertility and light availability beneath the canopy of parasitized trees, which have the potential to facilitate zoochorous-plant colonization, recruitment, and growth at the same time as it weakens the host. Here, we analyse whether mistletoe-driven changes could result in a nucleus of zoochorous woody plants nourished by the abundant organic detritus accumulated under the host. We also analyse whether mistletoe effects can expand after host death. 3. We selected unparasitized, parasitized, and dead parasitized Pinus nigra trees, in which we studied the joint effect of mistletoe-mediated changes in soil nutrient and light availability, with the seed rain, seed predation, seedling establishment, plant recruitment, and plant growth. Light- and soil-nutrient resources were greater under parasitized trees, and intensified after host death. The seed rain was maximum under parasitized trees, where seedling recruitment proved more likely. Sapling density, richness, and growth increased with the development of parasitism. 4. Our findings show that Viscum album exerts a strong and lasting impact on the structure and dynamics of Mediterranean pinelands, with parasitized trees acting as centres for the establishment and growth of colonizing fleshy-fruited woody species, which, over the long term, promote vegetation shifts by limiting dominant pine trees and facilitating less represented fleshy-fruited shrubs.

Data from: An active-radio-frequency-identification system capable of identifying co-locations and social-structure: validation with a wild free-ranging animal

Behavioural events that are important for understanding sociobiology and movement ecology are often rare, transient and localised, but can occur at spatially distant sites e.g. territorial incursions and co-locating individuals. Existing animal tracking technologies, capable of detecting such events, are limited by one or more of: battery life; data resolution; location accuracy; data security; ability to co-locate individuals both spatially and temporally. Technology that at least partly resolves these limitations would be advantageous. European badgers (Meles meles L.), present a challenging test-bed, with extra-group paternity (apparent from genotyping) contradicting established views on rigid group territoriality with little social-group mixing. In a proof of concept study we assess the utility of a fully automated active-radio-frequency-identification (aRFID) system combining badger-borne aRFID-tags with static, wirelessly-networked, aRFID-detector base-stations to record badger co-locations at setts (burrows) and near notional border latrines. We summarise the time badgers spent co-locating within and between social-groups, applying network analysis to provide evidence of co-location based community structure, at both these scales. The aRFID system co-located animals within 31.5 m (adjustable) of base-stations. Efficient radio transmission between aRFIDs and base-stations enables a 20 g tag to last for 2–5 years (depending on transmission interval). Data security was high (data stored off tag), with remote access capability. Badgers spent most co-location time with members of their own social-groups at setts; remaining co-location time was divided evenly between intra- and inter-social-group co-locations near latrines and inter-social-group co-locations at setts. Network analysis showed that 20–100% of tracked badgers engaged in inter-social-group mixing per week, with evidence of trans-border super-groups, that is, badgers frequently transgressed notional territorial borders. aRFID occupies a distinct niche amongst established tracking technologies. We validated the utility of aRFID to identify co-locations, social-structure and inter-group mixing within a wild badger population, leading us to refute the conventional view that badgers (social-groups) are territorial and to question management strategies, for controlling bovine TB, based on this model. Ultimately aRFID proved a versatile system capable of identifying social-structure at the landscape scale, operating for years and suitable for use with a range of species.

Data from: New Crystal Forms and Amorphous Phase of Sophoricoside: X-Ray Structures and Characterization

Sophoricoside, which is an isoflavone glycoside found in many plant species, has recently attracted attention because of its anti-fertility activity. One solvent-free form, two solvatomorphs and an amorphous phase of sophoricoside are reported for the first time. X-ray diffractometry, differential scanning calorimetry, thermal gravimetric analysis and Fourier-transform infrared spectroscopy were used to characterize the different forms. The results show that factors such as crystal symmetry, intermolecular arrangement, conformational flexibility, hydrogen-bonding interactions and solvent incorporation lead to different solid-state forms. An investigation of the transformations of the four forms showed that they can interconvert with each other under certain conditions. Amorphous phase and solvatomorphism were unstable but can improve the solubility of sophoricoside in water.

opencc-zeroNov 2019View details →

Data from: Fine-scale appendage structure of the Cambrian trilobitomorph Naraoia spinosa and its ontogenetic and ecological implications

Trilobitomorphs are a species-rich Palaeozoic arthropod assemblage that unites trilobites with several other lineages that share similar appendage structure. Post-embryonic development of the exoskeleton is well documented for some trilobitomorphs, especially trilobites, but little is known of the ontogeny of their soft parts, limiting understanding of their autecology. Here we document appendage structure of the Cambrian naraoiid trilobitomorph Naraoia spinosa by computed microtomography, resulting in three-dimensional reconstructions of appendages at both juvenile and adult stages. The adult has dense, strong spines on the protopods of post-antennal appendages, implying a predatory/scavenging behavior. Absence of such gnathobasic structures but instead tiny protopodal bristles and a number of endopodal setae suggests a detritus-feeding strategy for the juvenile. Our data add strong morphological evidence for ecological-niche shifting by Cambrian arthropods during their life cycles. A conserved number of appendages across the sampled developmental stages demonstrates that Naraoia ceased budding off new appendages by the mid-juvenile stage.

Data from: Impact of uniaxial tensile fatigue on the evolution of microscopic and mesoscopic structure of carbon black filled natural rubber

This investigation addresses the evolution of the microscopic and mesoscopic structures distribution, and micro-defects of carbon black (CB) filled natural rubber (NR) under uniaxial tensile condition during the fatigue process. NR was filled with three different grades CB respectively, in order to understand the impact of the structural degree and specific surface areas of CB and fatigue degree on the Payne effect. It was found that Payne effect was initially suppressed and then enhanced with increasing the degree of fatigue. The decrease of the storage modulus in the low strain area was attributed to the CB network destruction and the breakdown of the matrix cross-linking network in the early fatigue stage. However, with further increasing the degree of fatigue, the spatial rearrangement of CB aggregates with the orientation of molecular chains between adjacent CB aggregates will result in the mechanical reinforcement before the appearance of micro-defects. Moreover, it has been demonstrated that the structural degree of CB has a stronger impact on the mesoscopic structures than the specific surface area of CB during tensile fatigue process.