Fossil species that can be conclusively identified as stem-relatives of stick- and leaf-insects (Phasmatodea) are extremely rare, especially for the Mesozoic era. This dearth in the paleontological ...record makes assessments on the origin and age of the group problematic and impedes investigations of evolutionary key aspects, such as wing development, sexual size dimorphism and plant mimicry.
A new fossil insect species, Cretophasmomima melanogramma Wang, Béthoux and Ren sp. nov., is described on the basis of one female and two male specimens recovered from the Yixian Formation (Early Cretaceous, ca. 126±4 mya; Inner Mongolia, NE China; known as 'Jehol biota'). The occurrence of a female abdominal operculum and of a characteristic 'shoulder pad' in the forewing allows for the interpretation of a true stem-Phasmatodea. In contrast to the situation in extant forms, sexual size dimorphism is only weakly female-biased in this species. The peculiar wing coloration, viz. dark longitudinal veins, suggests that the leaf-shaped plant organ from the contemporaneous 'gymnosperm' Membranifolia admirabilis was used as model for crypsis.
As early as in the Early Cretaceous, some stem-Phasmatodea achieved effective leaf mimicry, although additional refinements characteristic of recent forms, such as curved fore femora, were still lacking. The diversification of small-sized arboreal insectivore birds and mammals might have triggered the acquisition of such primary defenses.
Near-net-shaped process (NNSP) will be one of important development trend in TC4 blade manufacturing, while the blade precise machining after NNSP is a challenge. This paper analyzes the machining ...deformation of blade under the rigid-flexible coupling fixture (RFCF) and adaptive computer numerical control machining process (ACNCMP). Firstly, positioning and clamping scheme (PCS) of RFCF were introduced and analyzed, especially new material (PEEK-GF30) and new structure of RFCF were used in fixture manufacturing. Secondly, theoretical mechanic model of RFCF and blade was proposed. Thirdly, empirical model of cutting force and the main cutting parameters was established and analyzed by orthogonal cutting experiment (OCE). Fourthly, blade deformation under cutting force was analyzed by FEA and experiment. The results show that blade cutting deformation is a whole elastic deformation of 0.056mm which is acceptable for machining accuracy target of 0.1mm. The proposed RFCF can protect blade from occurring local deformation, and is of better application value in ACNCMP of NNSP blade.
This study explores the impact of highland barley straw (HBS) fiber, an environmentally friendly material, on the molecular dynamics and performance of asphalt. Despite the widespread use of fibers ...in enhancing asphalt performance, molecular-scale investigations are lacking. In this study, molecular dynamics software was employed to model matrix asphalt and three types of HBS fiber-modified asphalt with varying cellulose contents (8.62 wt%, 15.88 wt%, 22.06 wt%). Thermodynamic parameters mean squared displacements (MSD), radial distribution function (RDF), free volume fraction (FFV), and mechanical parameters were analyzed through simulation to understand the diffusion behavior of HBS cellulose molecules in asphalt and study the modification mechanism. The findings revealed that the 8.62 wt% cellulose-modified asphalt had the slowest diffusion rate, with the most favorable temperature for asphalt diffusion being 298.15 K. Integration of HBS cellulose molecules facilitated the self-aggregation process of asphaltene-asphaltene and improved the compatibility between asphaltene-resin, resulting in asphalt stabilization. However, the study found that moisture damage weakened the water resistance of HBS cellulose-modified asphalt binder. Specifically, modifying asphalt with 8.62 wt% cellulose increased the Young modulus by 28.37%, bulk modulus by 39.77%, and shear modulus by 26.45%, demonstrating the overall improvement achieved with the combined effect of 8.62 wt% HBS cellulose-modified asphalt. These findings have significant implications for repurposing HBS as a solid waste material and enhancing the low-temperature crack resistance of asphalt binders.
•The molecular dynamics model of HBS fiber-modified asphalt was established.•The thermodynamic properties of HBS fiber-modified asphalt were investigated.•The optimum content and temperature of diffusion of HBS fiber molecules were proposed.•The compatibility of HBS fiber molecules with asphalt was predicted at the molecular scale.•The mechanical properties parameters of HBS fiber-modified asphalt were evaluated.
In recent years, there has been a growing trend in utilizing fibers to improve the crack resistance of asphalt mixtures. However, the examination of steel fiber’s impact on the crack resistance ...mechanism of hot recycled asphalt mixture remains limited. Steel fibers, characterized by its high strength, toughness, and robust self-healing properties, presents a promising avenue for enhancing the low-temperature performance of hot recycled asphalt mixture. This study investigates the macro- and micro-mechanisms underlying the low-temperature crack resistance of steel fiber-reinforced hot recycled asphalt mixture, to address significant deficiencies in their crack resistance at low temperatures. Five different schemes of steel fiber content (0.1 %, 0.2 %, 0.3 %, 0.4 %, and 0.5 %) were examined, and a three-dimensional numerical model of semi-circular bending (SCB) was constructed utilizing PFC3D (three-dimensional particle flow software). By converting and calibrating macro and micro parameters, meso parameters were defined within the model, yielding SCB simulation results for AC-16 and SMA-16 steel fiber hot recycled asphalt mixture. To evaluate the influence of steel fiber content on the low-temperature crack resistance of the hot recycled asphalt mixtures, fracture energy (Gf), crack resistance index (CRI), and balanced cracking index (BCI) were introduced as evaluation criteria. The simulation outcomes affirm that the disparity between the results of the three-dimensional virtual strength test and those of the indoor strength test remains within 6 %, thus validating the model’s viability. Notably, the failure cracks observed in AC-16 and SMA-16 hot recycled asphalt mixtures predominantly manifest at the interface between the asphalt mortar and recycled asphalt pavement (RAP). After the addition of steel fibers to these mixtures, the fracture energy (Gf) peaks at a steel fiber content of 0.3 %, showing increases of 41.46 % for AC-16 and 32.38 % for SMA-16, respectively. The optimal steel fiber content for both AC-16 and SMA-16 hot recycled asphalt mixtures, as determined by CRI and BCI, was found to be 0.3 %. Beyond the threshold of 0.3 %, the crack resistance diminishes. These findings may enhance the cracking performance of hot recycled asphalt mixture.
•The generation method of steel fiber in discrete element was proposed.•The modeling method of recycled asphalt mixture was proposed.•Microcrack development and stress in steel fiber hot recycled mixtures were discussed.•The influence of different steel fiber content on the mixture was analyzed.
Background Fossil species that can be conclusively identified as stem-relatives of stick- and leaf-insects (Phasmatodea) are extremely rare, especially for the Mesozoic era. This dearth in the ...paleontological record makes assessments on the origin and age of the group problematic and impedes investigations of evolutionary key aspects, such as wing development, sexual size dimorphism and plant mimicry. Methodology/Principal Findings A new fossil insect species, Cretophasmomima melanogramma Wang, Bethoux and Ren sp. nov., is described on the basis of one female and two male specimens recovered from the Yixian Formation (Early Cretaceous, ca. 126 plus or minus 4 mya; Inner Mongolia, NE China; known as 'Jehol biota'). The occurrence of a female abdominal operculum and of a characteristic 'shoulder pad' in the forewing allows for the interpretation of a true stem-Phasmatodea. In contrast to the situation in extant forms, sexual size dimorphism is only weakly female-biased in this species. The peculiar wing coloration, viz. dark longitudinal veins, suggests that the leaf-shaped plant organ from the contemporaneous 'gymnosperm' Membranifolia admirabilis was used as model for crypsis. Conclusions/Significance As early as in the Early Cretaceous, some stem-Phasmatodea achieved effective leaf mimicry, although additional refinements characteristic of recent forms, such as curved fore femora, were still lacking. The diversification of small-sized arboreal insectivore birds and mammals might have triggered the acquisition of such primary defenses.
Several studies have shown that microorganisms are key factors in the transformation of dark tea chemicals. However, these studies have mainly used relative abundance to study the diversity of the ...microbial community during tea fermentation. The dynamics of microbial density and assembly of abundant and rare microbes remains poorly understood. In this study, the entire manufacturing process of Qingzhuan brick tea (QBT) was studied at an industrial scale. The succession of both bacterial and fungal communities was investigated using high-throughput sequencing along with quantitative PCR (qPCR) analysis. Changes in non-volatile flavor components, including soluble sugar (SS), total polyphenols (TP), nine tea catechins, caffeine, 21 free amino acids, and three tea pigments were detected. Mantel test showed that both bacterial and fungal community structures were significantly correlated with environmental variables during the microbial fermentation process but not during the aging process. The absolute microbial density was calculated based on qPCR gene copies and relative abundance. The quantitative microbiota network showed that dominant microbes constitute the basic skeleton of the network, while rare microbes have a stronger correlation with various flavor contents. These results help to understand the assembly of microbial communities and their role in the formation of tea flavor substances.
•Microbes affect the flavor of fermented QBT during the microbial fermentation process but not during the aging process.•The content of GA, CAF, and GABA increased during the manufacturing process.•Bacterial community showed a stronger correlation with the global environmental variables than the fungal community.•Dominant microbes constitute the basic skeleton of the network.•Rare microbes showed strong correlation with various flavor contents.
A novel microbial consortium (NZDC-6) was screened and characterized to detoxify the estrogenic mycotoxin zearalenone (ZEA), which commonly contaminates maize and is a major threat to food and health ...security. We found NZDC-6 to be thermophilic and highly effective, with a 90.3% ZEA degradation ratio at an optimum temperature of 60 °C. NZDC-6 was also effective at degrading the more estrogenic ZEA cognates, α-zearalenol (α-ZAL) and β-zearalenol (β-ZAL), with >90% degradation ratios. To evaluate a practical application, ZEA-contaminated corncobs were treated with NZDC-6 via semisolid fermentation. Measurements of physicochemical parameters and 16S microbial diversity and redundancy analysis (RDA) indicated that ZEA removal was most efficient at a low corncob solid content (< 5%), as a high solid content overwhelmed the microbial metabolic load, leading to increased dissolved oxygen and lowered pH. Our results demonstrate that the control of environmental variables is crucial for effective ZEA microbial removal in practical applications.
Mycotoxins are toxic secondary metabolites mainly produced by filamentous fungal species that commonly contaminate staple foods and feeds. They cause significant economic losses and greatly harm food ...security. Simultaneous contamination of multiple mycotoxins and the accompanying additive and synergistic effects may cause even more serious harm. To develop a microbial consortium with the ability to degrade multiple mycotoxins, a previously identified consortium with aflatoxin B1 (AFB1) degradation ability, TADC7, was domesticated by co-culturing with 500 μg l−1 AFB1 and 500 μg l−1 zearalenone (ZEA), yielding the derived microbial consortium TMDC. After 168 h of co-culture with TMDC, 2000 μg l−1AFB1 and 2000 μg l−1 ZEA were degraded by 98.9% and 88.5%, respectively. The proteins or enzymes in the TADC7 cell-free supernatant played a major role in mycotoxins degradation. The degradation ratios of 5000 μg l−1 AFB1 and 5000 μg l−1 ZEA by 48 h TMDC cell-free supernatant were 93.8% and 90.3% at 72 h, respectively. Based on 16S rRNA sequencing, Geobacillus and Tepidimicrobium might play important roles in mycotoxin degradation by TMDC, and the TMDC community composition was stable, irrespective of mycotoxin. This study established the biodegradation of different categories of mycotoxins, and will facilitate the practical application of microbial consortia in mycotoxin degradation.
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•The microbial consortium TMDC simultaneously degraded aflatoxin B1 and zearalenone effectively.•Decontamination of mycotoxins by TMDC mainly was enzymatic degradation effect in the supernatants.•After 168 h of co-culture with TMDC, 2000 μg l−1 AFB1 and 2000 μg l−1 ZEA were degraded by 98.9% and 88.5%.•TMDC microbial composition was stable when cultured with AFB1 and ZEA.
Mycotoxins are toxic secondary metabolites mainly produced by filamentous fungal species that commonly contaminate staple foods and feeds. They cause significant economic losses and greatly harm food ...security. Simultaneous contamination of multiple mycotoxins and the accompanying additive and synergistic effects may cause even more serious harm. To develop a microbial consortium with the ability to degrade multiple mycotoxins, a previously identified consortium with aflatoxin B
(AFB
) degradation ability, TADC7, was domesticated by co-culturing with 500 μg l
AFB
and 500 μg l
zearalenone (ZEA), yielding the derived microbial consortium TMDC. After 168 h of co-culture with TMDC, 2000 μg l
AFB
and 2000 μg l
ZEA were degraded by 98.9% and 88.5%, respectively. The proteins or enzymes in the TADC7 cell-free supernatant played a major role in mycotoxins degradation. The degradation ratios of 5000 μg l
AFB
and 5000 μg l
ZEA by 48 h TMDC cell-free supernatant were 93.8% and 90.3% at 72 h, respectively. Based on 16S rRNA sequencing, Geobacillus and Tepidimicrobium might play important roles in mycotoxin degradation by TMDC, and the TMDC community composition was stable, irrespective of mycotoxin. This study established the biodegradation of different categories of mycotoxins, and will facilitate the practical application of microbial consortia in mycotoxin degradation.
Pig to human xenotransplantation is considered to be a possible approach to alleviate the shortage of human allografts. Porcine endogenous retrovirus (PERV) is the most significant pathogen in ...xenotransplantation. We screened for pigs that consistently did not transmit human-tropic replication competent PERVs (HTRC PERVs), namely, non-transmitting pigs. Then, we conducted whole-genome resequencing and full-length transcriptome sequencing to further investigate the sequence characteristics of one non-transmitting pig. Using
transmission assays, we found 5 (out of 105) pigs of the Chinese Wuzhishan minipig inbred line that did not transmit PERV to human cells, i.e., non-transmitting pigs. Whole-genome resequencing and full-length transcriptome sequencing of one non-transmitting pig showed that all of the
genes were defective at both the genome and transcript levels. We speculate that the defective PERV
genes in this pig might be attributable to the long-term inbreeding process. This discovery is promising for the development of a strain of highly homozygous and genetically stable pigs with defective PERV
genes as a source animal species for xenotransplantation.
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