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Cyprinus carpio var. Quanzhounensis, native to Quanzhou County, Guilin City, Guangxi, has a dark brown body color, translucent gill cover, and abdominal skin, and is an important farmed species in the local integrated rice-fishery industry. A comparative study on the skin of Cyprinus carpio var. Quanzhounensis revealed a lack of reflective guanine crystals on the body surface and a significantly higher melanin content than that of C. carpio var. Jian, which was tentatively considered the direct cause of variations in body color of this group. Iridocytes are a pigment cell species that contain regularly arranged guanine crystals, which are the key material basis for the metallic luster of the fish body surface. In species such as medaka (Oryzias latipes) and zebrafish (Danio rerio), the absence of guanine crystals is considered a manifestation of the absence of iridocyte differentiation and therefore is ideal for studying the mechanism of pigment cell differentiation. The pnp4a, Gbx2, sox10, tfec genes and other iridocyte-related genes have been mined using mutant materials, and we have uncovered the differentiation mechanism that regulates the formation of iridescent cells. C. carpio var. color has abundant genetic variation in body color and is a good material for studying the mechanism of body color determination in fish. The roles of ASIP and MC1R in the aggregation and distribution of melanin and formation of black spots in C. carpio var. color were verified. The guanine crystalline deletion trait of C. carpio var. Quanzhounensis may be loaded with regulatory mechanism diversity and mutation loci related to guanine crystal formation or iridescent cell differentiation. In addition, as a rice-fish culture species, the living environment of C. carpio var. Quanzhounensis harvestmen differ significantly from pond and net-pen culture species, requiring high resistance to disease, adversity, and transport. It is unclear whether the absence of guanine crystals in their skin leads to changes in their basal physiological state, and in-depth studies are beneficial for accurate assessment of culture performance. To reveal the structural basis and transcriptomic characteristics of guanine crystalline deficiency traits in the skin of C. carpio var. Quanzhounensis in this study, we selected the subscale tissues with the most significant differences in guanine crystalline distribution as the control material, and transmission electron microscopy was used to observe the tissue structure and full-length transcriptome sequencing to understand the structural and transcriptomic characteristics of guanine crystalline deficiency in the skin of C. carpio var. Quanzhounensis. The results of this study provide information for the analysis of body color traits, identification of economic traits, and utilization of germplasm resources. Transmission electron microscopy of the subscale tissue sections revealed two significant differences in the histological structure of C. carpio var. Quanzhounensis, and C. carpio var. Jian. First, guanine crystals were absent in C. carpio var. Quanzhounensis, whereas guanine crystals were widely present in the tissues of C. carpio var. Jian and cascading cavities were observed in the sections after guanine crystals were dislodged. Second, the number and density of melanin particles in the tissues of C. carpio var. Quanzhounensis harvestmen were significantly higher than those of C. carpio var. Jian, showing smaller, darker, and more numerous particles, which is consistent with the darker color and lack of silvery reflective material on the body surface of C. carpio var. Quanzhounensis harvestmen. The transcriptome characteristics were analyzed using Oxford Nanopore (ONT) sequencing technology, and 2.88~3.26 Gb of high-quality data were obtained for each sample. The number of full-length sequences after filtering ribosomal RNA for all sample data was 2 203 826~2 412 500, and the proportion of full-length sequences for each sample was 87.06%~88.57%. The comparison rate was 90.35%~92.46%. Variable splicing events in the transcripts were counted; 3 075 variable splicing events and 57 624 variable polyadenylation events were detected; and 15 615 new coding region sequences and 771 long-stranded non-coding RNAs were predicted. The number of exon jumps and intron retention in variable splicing events differed significantly (P

The growth environment significantly influences the intestinal microbiota of aquatic organisms. We investigated the composition and functional differences in the intestinal microbiota of red claw crayfish (Cherax quadricarinatus) in rice fields (RB) and ponds (PB) by 16S rDNA high-throughput sequencing technology. The results indicate that the Shannon, Simpson, Sobs, Chao1, and ACE indices of PB are all higher than those of RB, demonstrating greater diversity and richness of intestinal microbiota. The dominant phyla in the intestinal microbiota of the Cherax quadricarinatus were Proteobacteria, Tenericutes, and Firmicutes. Tenericutes and Proteobacteria were significantly more abundant in the RB than in the PB, while Planctomycetes and Firmicutes were significantly more abundant in the PB than in the RB. The results of network correlation analysis indicate that Proteobacteria and Firmicutes exhibit strong connectivity with other microbial groups in the gut microbiota of Cherax quadricarinatus, showing significant centrality. They play an important role in the interactions within the gut microbiota community. The dominant bacterial genera in the Cherax quadricarinatus’s gut were Citrobacter, Candidatus_Bacilloplasma, and Clostridium_sensu_stricto_1. The abundance of the genus Clostridium was significantly higher in the PB than in the RB, whereas the abundance of Candidatus_Hepatoplasma and Vibrio was significantly lower in the PB than in the RB. The prediction function of KEGG enrichment showed that the abundance of Amino acid metabolism, Biosynthesis of Other Secondary Metabolites, Transport and Catabolism, Cancers, and Nervous System, Substance Dependence were significantly higher in the PB, while the infectious diseases pathway was enriched in the RB. In summary, our results revealed significant differences in the composition and diversity of intestinal microbiota in the Cherax quadricarinatus between rice paddy and pond farming environments. The intestinal microbiota of the Cherax quadricarinatus grown in pond environments exhibit higher diversity and stability, manifested by an increase in beneficial bacteria abundance and a decrease in opportunistic pathogens. These findings significantly improve understanding of the complex relationship among Cherax quadricarinatus, intestinal microbiota, and the environment.

Abstract A three-dimensional conjugate tooth surface design method for Harmonic Drive with a double-circular-arc tooth profile is proposed. The radial deformation function of the flexspline (FS), obtained through Finite Element (FE) analysis, is incorporated into the kinematics model. By analyzing the FS tooth enveloping process, the optimization of the overlapping conjugate tooth profile is achieved. By utilizing the hobbing process, the three-dimensional machinable tooth surface of FS can be acquired. Utilizing the coning deformation of the FS, simulations are conducted to analyze the multi-section assembly and meshing motion of the machinable tooth surface. The FE method is utilized to analyze and compare the loaded contact characteristics. Results demonstrate that the proposed design method can achieve an internal gear pair consisting of a circular spline with a spur gear tooth surface and the FS with a machinable tooth surface. With the rated torque, approximately 24% of the FS teeth are engaged in meshing, and more than 4/5 of the tooth surface in the axial direction carries the load. The contact patterns, maximum contact pressure, and transmission error of the machinable tooth surface are 227.2%, 40.67%, and 71.24% of those on the spur gear tooth surface, respectively. It clearly demonstrates exceptional transmission performance.

Bellamya purificata is an important medicinal value and economically farmed species in China. However, because little is known about the genetic characteristics of this species, the utilization of high-quality germplasm resources is hindered. The study examined the genetic differentiation between, and the structure of 12 B. purificata populations in Guangxi using 7 microsatellite DNA markers. High genetic diversity occurred in each population, with mean observed heterozygosity 0.655 and a mean expected heterozygosity 0.832. Analysis of molecular variance reveals genetic diversity to be greater within (95.2%) than among populations (4.8%). Genetic differentiation between populations is weak (Fst = 0.048, P < 0.001), with mixing of genetic clusters prevalent at the level of the individual. Genetic flow exists between populations (Nm = 3.084-11.778), with Longshui and Guilin populations exchanging frequently. A Mantel test reveals a low correlation between geographic and genetic distances (r = 0.2482, P < 0.071), suggesting that dispersal between neighboring populations facilitates population exchange. No significant heterozygosity excess was observed for any population (P > 0.05), indicating a lack of recent genetic bottlenecks. The results provide important genetic information for B. purificata, and data for potential germplasm discovery and aquaculture development.

Rice flower carp (Cyprinus carpio rubrofuscus) has high economic value because of its tender meat. However, a comprehensive scientific evaluation of the meat quality and nutritional value of rice flower carp is still needed. At the same time, because of its fast growth and strong disease resistance, rice flower carp is widely popularized in rice field culture but without any research comparing its quality with the pond culture method. Although rice farming has high ecological value, the fish yield is low and its specifications are abnormal, which cannot guarantee the stability and safety of the commercial fish supply and limit the potential rice flower carp industrial benefits. In addition, some studies have shown that fish muscle quality can be affected by environmental conditions. This study aimed to comprehensively evaluate the muscle quality and nutritional value of the rice flower carp and investigate the relationships between the nutritional values and its culture conditions, providing data to increase the rice flower carp yield, economic efficiency, and farmed varieties available. Therefore, 6 000 Quanzhou rice flower carp (2.35±0.08 g) were randomly divided into ponds and rice field groups for the experiment (three replicates per group, with a density of 15 000/hm2). The pond culture group was fed with 3% of the commercially established everyday food per fish weight, while the rice field group was not fed. After 12 weeks, the fish were submitted to a 24 h period without food and anesthetized using MS-222 (USA, Sigma). The length and weight of 100 fish were measured for each treatment. For the rice field group and pond group, respectively, the lengths were (13.56±0.49) cm and (14.10±0.23) cm, and the weights were (73.19±7.02) g and (101.20±4.57) g. The muscle quality of 30 fish from each treatment was measured, including basic nutritional components, texture characteristics, and amino acid and fatty acid compositions. The nutritional level was compared between the pond and rice field groups using the FAO/WHO amino acid score, whole egg protein comparison, protein amino acid score (AAS), chemical score (CS), and essential amino acid index (EAAI). Moreover, no significant differences between the two culture methods were observed in relation to the total ash (P > 0.05). The crude protein and crude fat contents in the rice field group were significantly lower than in the pond group (P < 0.05), while moisture was significantly higher (P < 0.05). The viscosity of the rice field group was significantly lower than that of the pond group (P < 0.05), but the cohesion and shear force were significantly higher than those of the pond group (P < 0.05). There was no significant difference in the other texture indexes (P > 0.05). Essential amino acids (EAA) in both groups met the FAO/WHO standard. Among the 18 amino acids measured, the total amino acids (TAA), delicious amino acids (DAA), essential and nonessential amino acids (NEAA) were significantly lower in rice field conditions than in pond (P < 0.05), while the EAA/TAA and EAA/NEAA ratios were significantly lower in the pond group (P < 0.05). According to the amino acid score (AAS) and chemical score (CS), glutamic acid (Glu) was the most common amino acid in both groups, while the first and second limiting amino acids were tryptophan (Trp) and valine (Val). Among the 22 fatty acids observed, the contents of tridecanoic, pentadecanoic, palmitoleic, heptadecanoic, and docosatetraenoic acids were not significantly different between the two groups (P > 0.05). In contrast, the contents of linoleic, linolenic, and arachidonic acids in the pond group were significantly higher than those in the rice field group (P < 0.05), while 14 other fatty acids showed significantly lower contents in the pond group (P < 0.05). The monounsaturated fatty acid (MUFA) contents in the pond group were significantly higher (P < 0.05), while the EPA+DHA and n-3PUFA/n-6PUFA were significantly lower than those in the rice field group (P < 0.05). Overall, the contents of four main flavor amino acids (glutamic acid, glycine, alanine, and aspartic acid) in the rice field group were significantly lower than those in the pond group (P < 0.05). In conclusion, rice flower carp reared in both pond and rice field is a high-quality protein source. However, different cultural environments significantly influence the rice flower carp muscle nutritional value and quality, wherein a higher nutrient composition and amino acid score were observed in the pond environment. Concerning the fatty acids content, the muscle of rice flower carp reared in rice fields had higher EPA+DHA content and N-3/N-6 polyunsaturated fatty acid ratio, which is more suitable for people with hyperlipidemia and cardiovascular diseases. In addition, in terms of texture, the muscle of rice flower carp is chewier under the rice field rearing condition. Nevertheless, N-3PUFA shortages were observed in both culture conditions. Besides, fish in the pond group had better muscle nutrition than the rice field group. Different culture conditions can change rice flower carp's fatty acid composition and content to a certain extent, but none of the two conditions tested here could completely allay the lower N-3PUFA problem. Therefore, increasing the N-3PUFA content of rice flower carp is the key to improving its nutritional value, and pond culture conditions make this process easier to be manually controlled.

The transverse leakage of leaky surface acoustic waves (LSAWs) occurs on 42°YX-lithium tantalate substrates (42LT), which increases the insertion loss, narrows the bandwidth and flattens the roll-off of band 40/41 SAW filters and duplexers. In this work, LSAW characteristics with different metal materials and thicknesses are calculated by the finite element method (FEM), which determines the IDT material and thickness used for band 40/41 SAW filter design. To deeply understand transverse leakage and suppress it, the effects of different gap and dummy lengths on transverse leakage are simulated and discussed. Then, a new technique of using a wider dummy without any additional lithographic or depositing processes is proposed to suppress the leakage. Its effectiveness is validated by both simulations and experiments. Then, the technique is extended to applications of band 40 and 41 SAW filters. The experimental results show that with the wider dummy structure, the band 40 and 41 SAW filters achieve a more than 0.2 dB improvement in the insertion loss, a wider bandwidth and a steeper roll-off characteristic. This technique may also be extended to the other band SAW filter applications.

SAW devices with a multi-layered piezoelectric substrate have excellent performance due to advantages such as a high quality factor, Q, low loss insertion, large bandwidth, etc. Prior to manufacturing, a comprehensive analysis and proper design are essential to evaluating the device’s key performance indicators, including the Bode Q value, bandwidth, and transverse mode suppression. This study explored the performance of SAW resonators employing a 42°Y-X LiTaO3 (LT) thin-plate-based multi-layered piezoelectric substrate. The thicknesses for each layer of the 42°Y-X LT/SiO2/poly-Si/Si substrate were optimized according to the index of phase velocity, Bode Q value, and bandwidth. The effect of the device structure parameters on the dispersion curve and slowness curve was studied, and a flat slowness curve was found to be favorable for transverse mode suppression. In addition, the design of the dummy configuration was also optimized for the suppression of spurious waves. Based on the optimized design, a one-port resonator on the 42°Y-X LT/SiO2/poly-Si/Si substrate was fabricated. The simulation results and measurements are presented and compared, which provides guidelines for the design of new types of SAW devices configured with complex structures.

The rice flower carp (Cyprinus carpio) is an important fish in integrated rice-fishery farming. Here, we performed the first genome-wide association study (GWAS) for seven growth traits (including body mass, total length, body length, body height, body width, caudal-peduncle depth, and eye spacing) in 200 rice flower carp samples using 369,688 high-quality SNPs and 42,225 indels obtained by double-digest genotyping-by-sequencing (ddGBS). The morphometrics of these traits were highly correlated (Pearson’s correlation coefficients = 0.74–0.99, p < 0.001). GWAS detected 15, 5, 4, 26, 7, 16, and 17 loci significant associated (-log10P ≥ 5) with body mass, total length, body length, body width, body height, caudal-peduncle depth, and eye spacing, respectively. Subsequently, within the 50 kb upstream and downstream regions surrounding these significant loci, 38, 19, 18, 20, 52, 27, and 37 candidate genes for the seven growth traits were detected, respectively. Importantly, B6_4352672 and A8_4978825 were significantly associated with more than five growth traits. These results showed loci significantly associated with more than five growth traits will be helpful for future marker-assisted selection (MAS). Interestingly, chromosomes A8 and B25 had many loci significantly associated with growth traits, most of which were shared among multiple growth-related traits. These results indicated that chromosome A8 and B25 may be closely related to growth traits. Our findings not only help understand the genetic architecture of growth traits in fish but facilitate the identification of candidate genes for marker-assisted selection towards breeding faster-growing rice flower carp in the future.

Planetary roller screw mechanism (PRSM) is a novel high-performance linear transmission device. The non-uniformity of load distribution over PRSM threads is a vital problem severely affecting its load-carrying capacity and service performance. This work aims to develop a PRSM load distribution improvement approach with good manufacturability and general applicability. A roller taper modification method for load distribution optimization is proposed based on the deformation compatibility and force equilibrium, then the roller grinding experiment is carried out. Finally, the effects of external load and thread number on load sharing optimization are analyzed to examine the applicability. The results show that the maximum reduction in load sharing coefficient reaches 31.4% after roller taper modification under the case studied. The taper modification of roller threads could be rapidly implemented by only adjusting the roller grinding angle. The roller grinding experiment results agree well with the theoretical values, and the maximum error is no more than 2 μm. As the external load and thread number change, the improvement approach still works well. The proposed method has been verified by comparisons with finite element simulations and available references. This work can provide theoretical guidance for the optimal design of PRSM and has good engineering application prospects.

Relational integration is essential for learning, working, and living, as we must encode enormous volumes of information and extract their relations to construct knowledge about the environment. Recent research hints that generating distant analogies can temporarily facilitate learners’ state-based relational integration. This study aimed to investigate the internal mechanism underlying the facilitation effect and preliminarily confirm its application in education. First, we adopted the classical n-term premise integration task (Experiment 1a) and the Latin Square Task (Experiment 1b) to explore the robustness of the facilitation effect. Then we employed an emerging multidimensional relational reasoning task to further explore the internal mechanism underlying this facilitation effect (Experiment 2). Finally, we verified the practical role of the facilitation effect in learning the interaction concept in statistics (Experiment 3). The results showed that generating distant analogies did facilitate students’ relational integration performance, both in classical cognitive tasks and in a practical learning task, and a relational mindset and cognitive load play an intermediary role in the facilitation, supporting the cognitive load theory. The results suggest that generating distant analogies can be a useful warm-up activity to assist educators in promoting students’ relational integration.

Cipangopaludina chinensis is an economically important aquatic snail with high medicinal value. However, molecular biology research on C. chinensis is limited by the lack of a reference genome, so the analysis of its transcripts is an important step to study the regulatory genes of various substances in C. chinensis. Herein, we conducted the first full-length transcriptome analysis of C. chinensis using PacBio single-molecule real-time (SMRT) sequencing technology. We identified a total of 26,312 unigenes with an average length of 2,572 bp, of which the largest number of zf-c2h2 transcription factor families (120,18.24%) were found, and also observed that the majority of the 8,058 SSRs contained 4-7 repeat units, which provided data for subsequent work on snail genetics Subsequently, 91.86% (24,169) of the genes were successfully annotated to the four major databases, while the highest homology was observed with Pomacea canaliculata. Functional annotation revealed that the majority of transcripts were enriched in metabolism, signal transduction and Immune-related pathways, and several candidate genes involved in drug metabolism and immune response were identified (e.g., CYP1A1, CYP2J, CYP2U1, GST, ,PIK3, PDE3A, PRKAG). This study lays a foundation for future molecular biology research and provides a reference for studying genes associated with the medicinal value of C. chinensis.

Cipangopaludina chinensis is an important economic value snail species with high medicinal value. The gut microbes of aquatic animals plays a vital role in food digestion and nutrient absorption. Herein, we aimed at high-throughput sequencing of 16S rRNA to further investigate whether there were differences in the composition and function of gut microbes of adult and juvenile C. chinensis snails, as well as sediments. This study found that the microbial diversity of the sediment was significantly higher than that of the snails gut (P < 0.001), but there was no significant difference between the gut flora of adult and juvenile snails (P > 0.05). A total of 47 phyla and 644 genera were identified from all samples. Proteobacteria and Verrucomicrobia were the two dominant phyla in all samples, and overall relative abundances was 48.2% and 14.2%, respectively. Moreover, the relative abundances of Aeromonas and Luteolibacter in the gut of juvenile snails (30.8%, 11.8%) were higher than those of adults (27.7%, 10.6%) at the genus level (P > 0.05). Then, four indicator genera were found, namely Flavobacterium, Silanimonas, Geobacter and Zavarzinella, and they abundance in the gut of juvenile snails was significantly higher than that of adults (P < 0.05). This results imply the potential development of Silanimonas as a bait for juvenile snail openings. We observed that Aeromonas was the primary biomarker of the snail gut and sediments (P < 0.001), and it may be a cellulose-degrading bacteria. Function prediction revealed significantly better biochemical function in the snail gut than sediments (P < 0.001), but no significant differences in adult and juvenile snail (P > 0.05). In conclusion, studies show that the snail gut and sediment microbial composition differ, but the two were very similar. The microbial composition of the snail gut was relatively stable and has similar biological functions. These findings provide valuable information for in-depth understanding of the relationship between snails and environmental microorganisms.

The destruction of microbial communities within the gut of farmed tilapia (Oreochromis mossambicus) by Streptococcus agalactiae infection can result in considerable impacts to the health of the host. It is necessary to find a more effective treatment to improve the gut biome of farmed tilapia. We applied a tilapia culture method incorporating microorganisms in the diet and tracked gut bacteria over a 15-week period. A model of S. agalactiae infected individuals was constructed by detecting blood parameters and actual observation. Good’s coverage index (> 0.98) and < 1 % of reads was indicated by rarefaction curves. Healthy fish with no inclusion of microorganisms in the diet as reference group (RG), we assessed the effects of microorganisms on gut bacterial profiles and described changes in microbial richness and diversity via a comparison of the gut microbiota profiles of infected tilapia with (PD) and without (CG) the addition of microorganisms. An abnormal gut bacterial profile was associated with higher prevalence of infection by S. agalactiae, the lower Vibrio in PDs compared to the CGs, Spongiimonas spp. was present in all PDs and in the 3- and 6-week CGs, Photobacterium spp. appeared in all CGs and in the PDs at 3 and 6 weeks, Synechococcus, Shewanella, Spirochaeta, Psychromonas, Psychrilyobacter, Kiloniella, Allofrancisella, Candidatus Hepatoplasma, and Aliivibrio genera were only observed in the PDs, but Carboxylicivirga and Arcobacter were only detected in the CGs. Infected fish cultured using the combined microorganisms displayed significantly greater gut microbial species richness and diversity (Chao1; p-value < 0.001. Shannon’s; p-value < 0.001). The survival ratio of PDs (> 60 %) were higher than CGs. The application of the combined microorganisms within the diet of cultured O. mossambicus may therefore benefit their health by promoting a gut microbiome of greater diversity and increasing their resistance to disease.

The mathematical model of teeth distribution optimization for the promote gearbox is presented considering the objective functions such as the volume, efficiency, strength difference for the adjacent stages, and the design variables such as module, sun gear teeth, face width and transmission ratio of all stages. The improved genetic algorithm is used to solve the model and an analysis model of the promote gearbox is established using Masta to verify the proposed model. Results show that, after optimization, the attribute value of the synthesized objective function increases by 82.73%, the volume decreases by 17.61%, and the efficiency increases by 0.02%. The objective function value of equal contact and bending strength decreases by 55.93% and 51.10%, respectively. The difference for the safety coefficients for the adjacent stages decreases obviously. The constraint conditions of single-stage and adjacent stages satisfy the requirements. Through the strength verification calculation by the analysis model, the variation trend of the strength before and after optimization is consistent with the proposed optimization model, which indicates that the multi-objective optimization model established in this paper and the improved genetic algorithm selected are correct and effective.

Neovascularization is required in high-grade glioma (HGG). The objective of this study was to explore neovascularization-related genes and their corresponding MRI biomarkers during the early-growth stage of HGG. Tumor tissues from 30 HGG patients underwent perfusion MRI scanning prior to surgery were used to establish orthotopic xenograft models, pathologically analyze the tumor vasculature and perform transcriptome sequencing. The cases were divided into two groups based on whether the xenograft was successfully established. Microvascular density and BMPER, CXCL10, and HOXA9 expression of surgical specimens in the xenograft-forming group was significantly elevated and the microvascular diameter was significantly reduced, in vitro inhibition of BMPER, CXCL10, or HOXA9 in the glioma stem cell significantly suppressed its tube formation abilities. The in vivo experiment showed that BMPER was highly expressed in the early tumor growth phase (20 days), CXCL10 and HOXA9 expression was elevated with tumor progress, and spatially associated with tumor vasculature. Perfusion weighted MRI (PWI-MRI) derived parameters, rCBV, rCBF, Ktrans, and Vp, were also increased in the xenograft-forming group. In conclusion BMPER, CXCL10, and HOXA9 promote early tumor growth and progression by stimulating neovascularization of primary HGG. The rCBV, rCBF, Ktrans, and Vp can be used as imaging biomarkers to predict the expression statuses of these genes.

The earliest researches on application of GPS to earthquake monitoring and prediction in China began in 1980s, and it was limited to learn some relative technology from other countries and do some test with a few of equipments. As the improvement of software for data processing and the depreciating of hardware, several local GPS network had been gradually set up till the end of 1990s, and then more systematically GPS monitoring, data processing and its application research have been done gradually. In this paper, 3 research examples of the application of GPS to earthquake monitoring and prediction are presented.