Showing papers by "Fei Li published in 2017"

Exceptionally High Piezoelectric Coefficient and Low Strain Hysteresis in Grain-Oriented (Ba, Ca)(Ti, Zr)O3 through Integrating Crystallographic Texture and Domain Engineering

Abstract: Both low strain hysteresis and high piezoelectric performance are required for practical applications in precisely controlled piezoelectric devices and systems. Unfortunately, enhanced piezoelectric properties were usually obtained with the presence of a large strain hysteresis in BaTiO3 (BT)-based piezoceramics. In this work, we propose to integrate crystallographic texturing and domain engineering strategies into BT-based ceramics to resolve this challenge. [001]c grain-oriented (Ba0.94Ca0.06)(Ti0.95Zr0.05)O3 (BCTZ) ceramics with a texture degree as high as 98.6% were synthesized by templated grain growth. A very high piezoelectric coefficient (d33) of 755 pC/N, and an extremely large piezoelectric strain coefficient (d33* = 2027 pm/V) along with an ultralow strain hysteresis (Hs) of 4.1% were simultaneously achieved in BT-based systems for the first time, which are among the best values ever reported on both lead-free and lead-based piezoceramics. The exceptionally high piezoelectric response is mainly...

The Contributions of Polar Nanoregions to the Dielectric and Piezoelectric Responses in Domain-Engineered Relaxor-PbTiO3 Crystals

Abstract: The existence of polar nanoregions is the most important characteristic of relaxor-based ferroelectric materials. Recently, the contributions of polar nanoregions to the shear piezoelectric property of relaxor-PbTiO3 (PT) crystals are confirmed in a single domain state, accounting for 50%–80% of room temperature values. For electromechanical applications, however, the outstanding longitudinal piezoelectricity in domain-engineered relaxor-PT crystals is of the most significance. In this paper, the contributions of polar nanoregions to the longitudinal properties in [001]-poled Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 and [110]-poled Pb(Zn1/3Nb2/3)O3-0.15PbTiO3 (PZN-0.15PT) domain-engineered crystals are studied. Taking the [110]-poled tetragonal PZN-0.15PT crystal as an example, phase-field simulations of the domain structures and the longitudinal dielectric/piezoelectric responses are performed. According to the experimental results and phase-field simulations, the contributions of polar nanoregions (PNRs) to the longitudinal properties of relaxor-PT crystals are successfully explained on the mesoscale, where the PNRs behave as “seeds” to facilitate macroscopic polarization rotation and enhance electric-field-induced strain. The results reveal the importance of local structures to the macroscopic properties, where a modest structural variation on the nanoscale greatly impacts the macroscopic properties.

A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Abstract: Background: The Colorado potato beetle, Leptinotarsa decemlineata Say, is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to not only rapidly adapt to a broad range of solanaceaeous plants and variable climates during its global invasion, but, most notably, to rapidly evolve resistance to insecticides (over 50 different compounds in all major classes, in some cases within the first year of use). To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species, using whole-genome sequencing, transcriptome sequencing, and a large community-driven annotation effort. Results: We present a 140x coverage whole genome sequence from a single female L. decemlineata , with a reference gene set of 24,740 genes. Transposable elements comprise at least 17% of the genome, and are heavily represented in an analysis of rapidly evolving gene families compared to other Coleoptera. Population genetic analyses provide evidence of high levels of nucleotide diversity, local geographic structure, and recent population growth in pest populations, pointing to the availability of considerable standing genetic variation. These factors may play an important role in rapid evolutionary change. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes (e.g. cysteine peptidase genes) in gut tissues, as well as expansions of the gustatory receptors for bitter tasting plants in the nightshade family, Solanaceae. Despite its notoriety for adapting to insecticides, L. decemlineata has a similar suite of genes involved in resistance (metabolic detoxification and cuticle penetration) compared to other beetles, although expansions in specific cytochrome P450 subfamilies are known to be associated with insecticide resistance. Finally, this beetle has interesting duplications in RNAi genes that might be linked to its high sensitivity to RNAi and could be important in the future development of gene targeted pesticides. Conclusions: As a representative of one of the most evolutionarily diverse lineages, the L. decemlineata genome will undoubtedly provide new opportunities for deeper understanding on the ecology, evolution, and management of this species, as well as new opportunities to leverage genomic technologies to understand the basis of a broad range of phenotypes and to develop sustainable methods to control this widely successful pest.

Molecular insights into reproduction regulation of female Oriental River prawns Macrobrachium nipponense through comparative transcriptomic analysis.

Abstract: The oriental river prawn, Macrobrachium nipponense, is an important commercial aquaculture resource in China. During breeding season, short ovary maturation cycles of female prawns cause multi-generation reunions in ponds and affect the growth of females representing individual miniaturization (known as autumn -propagation). These reproductive characteristics pose problems for in large - scale farming. To date, the molecular mechanisms of reproduction regulation of M. nipponense remain unclear. To address this issue, we performed transcriptome sequencing and gene expression analyses of eyestalk and cerebral ganglia of female M. nipponense during breeding and non-breeding seasons. Differentially expressed gene enrichment analysis results revealed several important reproduction related terms and signaling pathways, such as “photoreceptor activity”, “structural constituent of cuticle” and “G-protein coupled receptor activity”. The following six key genes from the transcriptome were predicted to mediate environmental factors regulating reproduction of M. nipponense: neuroparsin, neuropeptide F II, orcokinin II, crustacean cardioactive peptide, pigment-dispersing hormone 3 and tachykinin. These results will contribute to a better understanding of the molecular mechanisms of reproduction of oriental river prawns. Further detailed functional analyses of the candidate reproduction regulation related neuropeptides are needed to shed light on the mechanisms of reproduction of crustacean.

Facile synthesis of three-dimensional (3D) interconnecting polypyrrole (PPy) nanowires/nanofibrous textile composite electrode for high performance supercapacitors

Abstract: In present work, polypyrrole (PPy) has been in-situ polymerized on a poly(vinyl alcohol- co -ethylene) (PVA- co -PE) nanofirous textile to form a 3D interconnecting PPy nanowires/nanofibrous textile composite electrode (designated as NW-PPy/NFs/PET). It demonstrates that the introduction of anthraquinone-2-sulfonic acid sodium (AQS) can tune the morphology of PPy from nanospheres to nanowires. The resulting PPy@PVA- co -PE conformal nanofibers act as bridges among intertwined PPy@PET fibers and PPy nanowires, leading to continuous pathways for ion/electron transfer and larger surface area for faradic reaction. Benefiting from this unique structure, the two-electrode supercapacitor using NaCl solution as electrolyte delivers a high power density of 800 W kg −1 at an energy density of 20 W h kg −1 per mass of active materials. Furthermore, the symmetric all-solid-state NW-PPy/NFs/PET supercapacitor demonstrates high flexibility and cycle stability. Therefore, this work may open a new way to develop light weight and cost-effective electrodes for flexible energy storage devices.

Electric-Field Control of Oxygen Vacancies and Magnetic Phase Transition in a Cobaltite/Manganite Bilayer

Abstract: Understanding the behavior of oxygen vacancies in an oxide multilayer in an electric field continues to be challenging, due to their complex transport between layers. In this study, a cycle of electronic phase transitions in a SrCoO${}_{3-x}$/La${}_{0.45}$Sr${}_{0.55}$MnO${}_{3-y}$ heterostructure is realized by sweeping an applied voltage, confirming that field-induced formation and annihilation of O vacancies is chiefly determined by their formation energies and differences in Gibbs free energies. These results yield important insight into control mechanisms for oxide electronics, including multiferroic tunnel junctions and solid-oxide fuel cells.

Multiple miRNAs jointly regulate the biosynthesis of ecdysteroid in the holometabolous insects, Chilo suppressalis

Abstract: The accurate rise and fall of active hormones is important for insect development. The ecdysteroids must be cleared in a timely manner. However, the mechanism of suppressing the ecdysteroid biosynthesis at the right time remains unclear. Here, we sequenced a small RNA library of Chilo suppressalis and identified 300 miRNAs in this notorious rice insect pest. Microarray analysis yielded 54 differentially expressed miRNAs during metamorphosis development. Target prediction and in vitro dual-luciferase assays confirmed that seven miRNAs (two conserved and five novel miRNAs) jointly targeted three Halloween genes in the ecdysteroid biosynthesis pathway. Overexpression of these seven miRNAs reduced the titer of 20-hydroxyecdysone (20E), induced mortality, and retarded development, which could be rescued by treatment with 20E. Comparative analysis indicated that the miRNA regulation of metamorphosis development is a conserved process but that the miRNAs involved are highly divergent. In all, we present evidence that both conserved and lineage-specific miRNAs have crucial roles in regulating development in insects by controlling ecdysteroid biosynthesis, which is important for ensuring developmental convergence and evolutionary diversity.

Investigation of morphotropic phase boundaries in PIN–PSN–PT relaxor ferroelectric ternary systems with high Tr-t and Tc phase transition temperatures

Abstract: New morphotropic phase boundary (MPB) compositions with relatively high T c s were projected in Pb(In 1/2 Nb 1/2 )O 3 –Pb(Sc 1/2 Nb 1/2 )O 3 –PbTiO 3 (PIN–PSN–PT) solid solution based on the perovskite tolerance factor, and were experimentally confirmed. The phase structure, dielectric, pyroelectric, piezoelectric and ferroelectric properties of PIN–PSN–PT ceramics were investigated. The rhombohedral–tetragonal phase transition temperatures T r-t on the order of 189–210 °C, Curie temperatures T c on the order of 274–285 °C and piezoelectric coefficients d 33 in the range of 310–360 pC/N, were achieved in x PIN– (1 − x )PSN–0.37PT ( x = 0.15–0.23) ceramics, demonstrating a promising relaxor–PbTiO 3 system with high phase transition temperatures. In addition, the maps of T c , T r-t , d 33 and e r with respect to composition were established, based on which, a clear direction for composition screening in future crystal growth of the PIN–PSN–PT system was given.

Electric-field control of oxygen vacancy and magnetic phase transition in cobaltite/manganite bilayer

Abstract: Manipulation of oxygen vacancies (V_O) in single oxide layers by varying the electric field can result in significant modulation of the ground state. However, in many oxide multilayers with strong application potentials, e.g. ferroelectric tunnel junctions and solid-oxide fuel cells, understanding V_O behaviour in various layers under an applied electric field remains a challenge, owing to complex V_O transport between different layers. By sweeping the external voltage, a reversible manipulation of V_O and a corresponding fixed magnetic phase transition sequence in cobaltite/manganite (SrCoO3-x/La0.45Sr0.55MnO3-y) heterostructures are reported. The magnetic phase transition sequence confirms that the priority of electric-field-induced V_O formation/annihilation in the complex bilayer system is mainly determined by the V_O formation energies and Gibbs free energy differences, which is supported by theoretical analysis. We not only realize a reversible manipulation of the magnetic phase transition in an oxide bilayer, but also provide insight into the electric field control of V_O engineering in heterostructures.

Large-scale analysis reveals that the genome features of simple sequence repeats are generally conserved at the family level in insects.

Abstract: Simple sequence repeats (SSR), also called microsatellites, have been widely used as genetic markers, and have been extensively studied in some model insects. At present, the genomes of more than 100 insect species are available. However, the features of SSRs in most insect genomes remain largely unknown. We identified 15.01 million SSRs across 136 insect genomes. The number of identified SSRs was positively associated with genome size in insects, but the frequency and density per megabase of genomes were not. Most insect SSRs (56.2−93.1%) were perfect (no mismatch). Imperfect (at least one mismatch) SSRs (average length 22−73 bp) were longer than perfect SSRs (16−30 bp). The most abundant insect SSRs were the di- and trinucleotide types, which accounted for 27.2% and 22.0% of all SSRs, respectively. On average, 59.1%, 36.8%, and 3.7% of insect SSRs were located in intergenic, intronic, and exonic regions, respectively. The percentages of various types of SSRs were similar among insects from the same family. However, they were dissimilar among insects from different families within orders. We carried out a phylogenetic analysis using the SSR frequencies. Species from the same family were generally clustered together in the evolutionary tree. However, insects from the same order but not in the same family did not cluster together. These results indicated that although SSRs undergo rapid expansions and contractions in different populations of the same species, the general genomic features of insect SSRs remain conserved at the family level. Millions of insect SSRs were identified and their genome features were analyzed. Most insect SSRs were perfect and were located in intergenic regions. We presented evidence that the variance of insect SSRs accumulated after the differentiation of insect families.

Assessment of municipal infrastructure development and its critical influencing factors in urban China: A FA and STIRPAT approach.

Abstract: Municipal infrastructure is a fundamental facility for the normal operation and development of an urban city and is of significance for the stable progress of sustainable urbanization around the world, especially in developing countries. Based on the municipal infrastructure data of the prefecture-level cities in China, municipal infrastructure development is assessed comprehensively using a FA (factor analysis) model, and then the stochastic model STIRPAT (stochastic impacts by regression on population, affluence and technology) is examined to investigate key factors that influence municipal infrastructure of cities in various stages of urbanization and economy. This study indicates that the municipal infrastructure development in urban China demonstrates typical characteristics of regional differentiation, in line with the economic development pattern. Municipal infrastructure development in cities is primarily influenced by income, industrialization and investment. For China and similar developing countries under transformation, national public investment remains the primary driving force of economy as well as the key influencing factor of municipal infrastructure. Contribution from urbanization and the relative consumption level, and the tertiary industry is still scanty, which is a crux issue for many developing countries under transformation. With economic growth and the transformation requirements, the influence of the conventional factors such as public investment and industrialization on municipal infrastructure development would be expected to decline, meanwhile, other factors like the consumption and tertiary industry driven model and the innovation society can become key contributors to municipal infrastructure sustainability.

Molecular characterization, expression and antimicrobial activities of two c-type lysozymes from manila clam Venerupis philippinarum.

Abstract: Lysozymes play an important role in the innate immune responses with which mollusks respond to bacterial invasion through its lytic activity. In the present study, two c-type lysozymes (designed as VpCLYZ-1 and VpCLYZ-2, respectively) were identified and characterized from the manila clam Venerupis philippinarum. The full-length cDNA of VpCLYZ-1 and VpCLYZ-2 was of 629 and 736 bp, encoding a polypeptide of 156 and153 amino acid residues, respectively. The deduced amino acid sequences of VpCLYZs showed high similarity to other known invertebrate c-type lysozymes. Multiple alignments and phylogenetic relationship strongly suggested that VpCLYZ-1 and VpCLYZ-2 belonged to the c-type lysozyme family. Both VpCLYZ-1 and VpCLYZ-2 transcripts were constitutively expressed in a wide range of tissues with different levels. The VpCLYZ-1 transcript was dominantly expressed in hepatopancreas and hemocytes, while VpCLYZ-2 transcript was mainly expressed in the tissues of hepatopancreas and gills. Both the mRNA expression of VpCLYZ-1 and VpCLYZ-2 was significantly up-regulated at 12 h post Vibrio anguillarum challenge. The recombinant VpCLYZ-1 and VpCLYZ-2 (designed as rVpCLYZ-1 and rVpCLYZ-2) exhibited lytic activity against all tested bacteria, and rVpCLYZ-1 showed higher activities than rVpCLYZ-2 in killing Micrococcus luteus and V. anguillarum. Overall, our results suggested that VpCLYZ-1 and VpCLYZ-2 belonged to the c-type lysozyme family, and played important roles in the immune responses of manila clam, especially in the elimination of pathogens.

Insights into the dielectric response of ferroelectric relaxors from statistical modeling

Abstract: Ferroelectric relaxors are complex materials with distinct properties. The understanding of their dielectric susceptibility, which strongly depends on both temperature and probing frequency, has been a challenge for researchers for many years. Here we report a macroscopic and phenomenological approach based on statistical modeling to investigate how the dielectric response of a relaxor depends on temperature. Employing the Maxwell-Boltzmann distribution and considering temperature-dependent dipolar orientational polarizability, we propose a minimum statistical model and specific equations to understand and fit numerical and experimental dielectric responses versus temperature. We show that the proposed formula can successfully fit the dielectric response of typical relaxors, including $\mathrm{Ba}(\mathrm{Zr},\mathrm{Ti}){\mathrm{O}}_{3},\phantom{\rule{0.28em}{0ex}}0.87\mathrm{Pb}({\mathrm{Zn}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}\text{\ensuremath{-}}0.13{\mathrm{PbTiO}}_{3},\phantom{\rule{0.28em}{0ex}}0.95\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}\text{\ensuremath{-}}0.05\mathrm{Pb}({\mathrm{Zr}}_{0.53}{\mathrm{Ti}}_{0.47}){\mathrm{O}}_{3}$, and Bi-based compounds, which demonstrates the general applicability of this approach.

Flexoelectric behavior in PIN-PMN-PT single crystals over a wide temperature range

Abstract: Flexoelectricity couples strain gradient to polarization and usually exhibits a large coefficient in the paraelectric phase of the ferroelectric perovskites. In this study, we employed the relaxor 0.3Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PIN-PMN-PT) single crystals to study the relationship between flexoelectric coefficients and the crystal structure. The flexoelectric coefficients in PIN-PMN-PT single crystal are found to vary from 57 μC/m at orthorhombic/monoclinic phase to 135 μC/m at tetragonal phase, and decreases to less than 27 μC/m in the temperature above Tm. This result discloses that ferroelectricity can significantly enhance the flexoelectricity in this kind of perovskite.

ACE: an efficient and sensitive tool to detect insecticide resistance-associated mutations in insect acetylcholinesterase from RNA-Seq data.

Abstract: Insecticide resistance is a substantial problem in controlling agricultural and medical pests. Detecting target site mutations is crucial to manage insecticide resistance. Though PCR-based methods have been widely used in this field, they are time-consuming and inefficient, and typically have a high false positive rate. Acetylcholinesterases (Ace) is the neural target of the widely used organophosphate (OP) and carbamate insecticides. However, there is not any software available to detect insecticide resistance associated mutations in RNA-Seq data at present. A computational pipeline ACE was developed to detect resistance mutations of ace in insect RNA-Seq data. Known ace resistance mutations were collected and used as a reference. We constructed a Web server for ACE, and the standalone software in both Linux and Windows versions is available for download. ACE was used to analyse 971 RNA-Seq data from 136 studies in 7 insect pests. The mutation frequency of each RNA-Seq dataset was calculated. The results indicated that the resistance frequency was 30%–44% in an eastern Ugandan Anopheles population, thus suggesting this resistance-conferring mutation has reached high frequency in these mosquitoes in Uganda. Analyses of RNA-Seq data from the diamondback moth Plutella xylostella indicated that the G227A mutation was positively related with resistance levels to organophosphate or carbamate insecticides. The wasp Nasonia vitripennis had a low frequency of resistant reads (<5%), but the agricultural pests Chilo suppressalis and Bemisia tabaci had a high resistance frequency. All ace reads in the 30 B. tabaci RNA-Seq data were resistant reads, suggesting that insecticide resistance has spread to very high frequency in B. tabaci. To the best of our knowledge, the ACE pipeline is the first tool to detect resistance mutations from RNA-Seq data, and it facilitates the full utilization of large-scale genetic data obtained by using next-generation sequencing.

Knockdown of two Cadherin genes confers resistance to Cry2A and Cry1C in Chilo suppressalis

Abstract: Bacillus thuringiensis (Bt) Cry toxins play an important role in the management of insect pests. Resistance to Bt toxins has been reported in many pest insects but the mechanism responsible for this resistance in rice crop pests remains largely unknown. Cadherin is one of several Bt toxin receptors. At present, only one cadherin gene, CsCAD1, has been documented in the striped rice stem borer, Chilo suppressalis. We amplified a nearly full-length transcript of another C. suppressalis cadherin gene, CsCAD2, and found that it has a different expression pattern to CsCAD1. CsCAD1 was highly expressed in fifth and sixth instar larvae, especially in the midgut, while the expression levels of CsCA2 were equably in each developmental stage. Newly hatched larvae were fed on rice smeared with synthesized siRNA to knockdown either CsCAD1 or CsCAD2, and then were fed transgenic rice expressing either the Cry2A or Cry1C toxins. The siRNA-treatment groups had lower mortality and higher survival rates than the control group, suggesting that reduced expression of CsCAD1 or CsCAD2 increased resistance to Cry2A and Cry1C. We conclude that CsCAD1 and CsCAD2 interact with Bt toxins in C. suppressalis and that this interaction could be the mechanism underlying Bt resistance in this insect.

Comparative transcriptome analysis of venom glands from Cotesia vestalis and Diadromus collaris , two endoparasitoids of the host Plutella xylostella

Abstract: Venoms secreted by the venom gland (VG) of parasitoid wasp help ensure successful parasitism by host immune suppression and developmental regulation. Cotesia vestalis, a larval endoparasitoid, and Diadromus collaris, a pupal endoparasitoid, parasitize the diamondback moth (DBM), Plutella xylostella. To explore and compare the venom components of two endoparasitoids, we sequenced transcriptomes of the VGs and wasp bodies without VGs (BWVGs) of the two endoparasitoids. Statistically enriched GO terms and KEGG pathways of the two VGs compared to respective whole-body background were similar and reflected active protein biosynthesis activities in the two VGs. 1,595 VG specific genes of the D. collaris VG and 1,461 VG specific genes of the C. vestalis VG were identified by comparative transcript profiling. A total of 444 and 513 genes encoding potential secretory proteins were identified and defined as putative venom genes in D. collaris VG and C. vestalis VG, respectively. The putative venom genes of the two wasps showed no significant similarity or convergence. More venom genes were predicted in D. collaris VG than C. vestalis VG, especially hydrolase-coding genes. Differences in the types and quantities of putative venom genes shed light on different venom functions.

Frequency dispersion of flexoelectricity in PMN-PT single crystal

Abstract: The mechanism of the recent discovered enhanced flexoelectricity in perovskites has brought about numerous controversies which still remain unclear. In this paper, we employed relaxor 0.68Pb(Mg2/3Nb1/3)O3 -0.32PbTiO3 (PMN-PT) single crystals for study. The observed flexoelectric coefficient in PMN-PT single crystal reaches up to 100 μC/m, and in a relative low frequency range, exhibits an abnormal frequency dispersion phenomenon with a positive relationship with frequency. Such frequency dispersion regulation is different from the normal relaxation behavior that usually occur a time delay, and hence proves the flexoelectricity acting more like bulk effect rather than surface effect in this kind of materials.

Preparation and characterization of a novel silicon-modified nanobubble

Abstract: Nanobubbles (NBs) opened a new field of ultrasound imaging There is still no practical method to control the diameter of bubbles In this study, we developed a new method to control the size by incorporating of silicon hybrid lipids into the bubble membrane The range of particle size of resulting NBs is between 52302 ± 4645 to 85718 ± 8290, smaller than the conventional microbubbles The size of resulting NBs increased with the decrease in amount of silicon hybrid lipids, indicating the diameter of NBs can be regulated through modulating the ratio of silicon hybrid lipids in the bubble shell Typical harmonic signals could be detected The in vitro and in vivo ultrasound imaging experiments demonstrated these silicon-modified NBs had significantly improved ultrasound contrast enhancement abilities Cytotoxicity assays revealed that these NBs had no obvious cytotoxicity to the 293 cell line at the tested bubble concentration Our results showed that the novel NBs could use as nanoscale ultrasound contrast agents, providing the foundation for NBs in future applications including contrast-enhanced imaging and drug/gene delivery

Two Bombyx Mori Acetylcholinesterase Genes Influence Motor Control and Development in Different Ways

Abstract: Among its other biological roles, acetylcholinesterase (AChE, EC 3.1.1.7), encoded by two ace in most insects, catalyses the breakdown of acetylcholine, thereby terminating synaptic transmission. ace1 encodes the synaptic enzyme and ace2 has other essential actions in many insect species, such as Chilo suppressalis and Plutella xylostella. The silkworm, Bombyx mori, has been domesticated for more than two thousand years and its aces have no history of pesticide exposure. Here, we investigated the functional differences between two ace genes, BmAce1 and BmAce2, in the silkworm. qPCR analysis indicated that BmAce1 is highly expressed in muscle and BmAce2 is more ubiquitously expressed among tissues and enriched in the head. Both genes were separately suppressed using chemically synthesized siRNAs. The mRNA abundance of the two ace genes was significantly reduced to about 13% - 75% of the control levels after siRNA injection. The AChE activities were decreased to 32% to 85% of control levels. Silencing BmAce2 resulted in about 26% mortality, faster and higher than the 20% in the siBmAce1-treated group. Silencing BmAce1 impacted motor control and development to a greater extent than silencing BmAce2, although both treatment groups suffered motor disability, slowed development and reduced cocoons. Both genes have essential, differing biological significance.

A high-fat diet impairs reproduction by decreasing the IL1β level in mice treated at immature stage

Abstract: Obesity causes low-grade inflammation that is involved in male infertility. Interleukin 1 beta (IL1β) plays an important role in this process. A high-fat diet (HFD) is the most common cause of obesity. However, the effect of a HFD on IL1β and its consequence in reproduction remain unclear. We established a HFD model in mice treated at immature stage (mice-TIS) and mice treated at mature stage (mice-TMS). Surprisingly, we found that a HFD decreased IL1β levels and was accompanied by an increase in testosterone in mice-TIS, while the reverse results were observed in mice-TMS. In addition, a HFD caused a reduction in testis macrophages and in the expression of inflammasome-related genes and proteins in mice-TIS. Furthermore, we found that IL1β inhibited testosterone secretion through down-regulating the gene expression of P450SCC and P450c17. However, the influence on mice-TIS that were induced by a HFD was recovered by stopping the HFD. In this study, we are the first to report that a HFD impairs the reproductive system by decreasing IL1β and enhancing testosterone levels in mice-TIS, which are different from the effects in mice-TMS. This provides new ideas for the treatment of obesity-induced infertility.

A novel flexible tactile sensor based on Ce-doped BaTiO3 nanofibers

Abstract: The performance of a robotic hand is severely limited by the tactile feedback information similar to a human hand. Hence, a novel and robust tactile sensor has been developed to cope with the challenge of robotic hand technology. Piezoelectric material is proposed as a suitable candidate for a new efficient tactile sensor due to its excellent piezoelectric properties. In this paper, a novel flexible tactile sensor based on Ce-doped BTO nanofibers was developed. The doping mechanism of cerium ions and the working process of the sensor were analysed. The results showed that sheer stress had no contribution to the sensor, this indicated that the sensor was easy to control according to the individual's wish. The output voltage of the sensor could reach up to 0.078 V which showed great potential for the future of intelligent robot skin application.