49 research outputs found

    Tri-trophic Analyses of Rice, the Sugarcane Borer, and Putative Biological Control Agents

    Get PDF
    A three-year field experiment was conducted to evaluate the tolerance and compensatory response of rice (Oryza sativa L.) to injury caused by the sugarcane borer, Diatraea saccharalis (F.). Two mechanisms of within-plant tolerance/compensation were observed. Stem injured plants produced ca. 0.69 more tillers than uninjured plants, while tillers with leaf and leaf sheath injury produced larger panicles, up to 39.5% and 21.0% heavier than uninjured tillers, when injury occurred at 3rd tiller stage and at panicle differentiation, respectively. A 2-year field cage experiment was conducted to determine the biological control potential of Cotesia flavipes (Cameron) against the sugarcane borer on rice. The effective search rate was 49 cm2 ground area (2.2 tillers) parasitoid-1 day-1. A cohortbased age-structured model was developed to simulate the population dynamics and economic value of the sugarcane borer and C. flavipes in rice, as affected by overwintering larval density, timing and rate of parasitoid aerial release, and year-to-year climate (temperature and rainfall). The results suggest C. flavipes was most effective when released during the 1st sugarcane borer generation. The maximum simulated economic benefit (112.05ha−1)wasca.7.8control.TheinabilityofC.flavipestoprovideeconomiccontrolintemperate−subtropicalareasisduetoitshighrearingcost,aloweffectivesearchrate,alowmaximumrateofparasitismperfemale,andbothspatialandtemporalasynchronyofparasitoidemergencewiththelarvalhosts.ThebiocontrolcapabilityofTrichogrammagalloiZucchiwasalsosimulated.ThemaximumeconomicbenefitprovidedbyT.galloiwas112.05 ha-1) was ca. 7.8% of that provided by insecticide-based control. The inability of C. flavipes to provide economic control in temperate-subtropical areas is due to its high rearing cost, a low effective search rate, a low maximum rate of parasitism per female, and both spatial and temporal asynchrony of parasitoid emergence with the larval hosts. The biocontrol capability of Trichogramma galloi Zucchi was also simulated. The maximum economic benefit provided by T. galloi was 1128.75 ha-1, ca. 79.0% of that provided by insecticide-based control. Theoretical analyses were conducted to estimate the effectiveness of augmentative releases, using data from previous studies of parasitism of lepidopteran pests by hymenopteran parasitoids with host and parasitoid density as factors. The maximum daily parasitism per female was highest for parasitoids that attack exposed larvae, followed by parasitoids that attack eggs, semi-exposed larvae, and concealed larvae. Simulation analyses were conducted to estimate the population dynamics and economic value of D. saccharalis, herein used as a model host, and each of 5 parasitoid categories (solitary parasitoids that attack eggs, exposed larvae, and semi-exposed larvae, gregarious parasitoids that attack eggs and concealed larvae) in rice, as affected by overwintering larval density, timing of parasitoid release, and year-to-year climate. Among the 13,500 simulations that were conducted, 480 (3.6%) provided a greater economic value than insecticide-based control. All 480 simulations were obtained using solitary parasitoids that attack exposed or semi-exposed larvae. Solitary egg parasitoids provided an average of 42.2% of the economic value provided by insecticide-based control when released 30 days after planting. Gregarious parasitoids that attack eggs or concealed larvae provided almost no positive economic benefit. For parasitoid species that do not overwinter successfully in areas where they are released or that exhibit temporal or spatial asynchrony with their host early in the spring, our results suggest augmentative biological control is only effective for solitary parasitoids that attack either exposed or semi-exposed larvae, with current rearing, shipping and release costs

    Study on Surface Roughness Improvement of Selective Laser Melted Ti6Al4V Alloy

    No full text
    To improve the surface quality of Ti6Al4V parts formed by selective laser melting (SLM), this paper systematically studies the effects of laser power, scanning speed and inclination angle on the different surface morphology and roughness of parts. On this basis, the effect of surface remelting and multi-layer profile scanning process strategies on improving the surface quality of parts is explored. The upper surface roughness varies parabolically with increasing line energy density, the line energy density value that minimizes the upper surface roughness is around 0.22 J/mm, and the minimum Ra value is 4.41 μm. The roughness of upper and lower sides increases significantly with the increase in scanning speed. As the inclination angle increases, the roughness of the upper and lower sides gradually decreases, which is caused by the combined influence of powder adhesion and step effect. The surface remelting process strategy can reduce the upper surface roughness by 35.68% and reduce its Ra value to 2.65 μm. The multi-layer profile scanning process strategy can reduce the upper side and vertical side roughness by more than 50%, down to Ra 5.10 μm and Ra 4.61 μm, respectively

    Multimodal AI System for the Rapid Diagnosis and Surgical Prediction of Necrotizing Enterocolitis

    No full text
    The rapid diagnosis and surgical prediction of necrotizing enterocolitis (NEC) remain a challenge because its complex pathogenesis has not been completely elucidated, and no single medical examination is specific for diagnosing NEC. Artificial intelligence (AI) has proven the robustness of multivariate analysis and been widely used in the diagnosis of complex diseases in the past decade. In this paper, a new multimodal AI system including feature engineering, machine learning (ML), and deep learning (DL) was constructed based on abdominal radiographs (ARs) and clinical data. A total of 4,535 ARs from 1,823 suspected NEC patients were analyzed by transfer learning, and then medical images and clinical parameters from 827 suspected NEC patients were used to train, validate, and test the AI system. Our results demonstrated that the system was effective in diagnosing NEC. In addition, the clinical datasets obtained one week before surgery from 379 NEC patients were studied by the multimodal AI system, and the results showed that it was capable of predicting which NEC patients required surgery. We compared the results in external test sets with those made by clinicians and found that the diagnostic and surgical predictive ability of the AI system was equivalent to that of experienced clinicians. This multimodal AI system can help clinicians improve diagnostic efficiency, reduce the number of missed diagnoses, and facilitate early diagnosis and treatment to prevent disease progression or even death

    Updated Lagrangian particle hydrodynamics (ULPH) modeling for free-surface fluid flows

    No full text
    In this work, we develop an accurate and stable Updated Lagrangian particle hydrodynamics (ULPH) modeling to simulate complicated free-surface fluid flows. Leveraging its inherent properties as a Lagrangian particle method, the ULPH has natural advantages in modeling free-surface flows. However, similar to other meshfreemethods, ULPH is subject to numerical instabilities and non-physical pressure fluctuations when solving the Navier-Stokes equation in the explicit numerical scheme. Within the framework of the ULPH method, several innovative enhanced treatment techniques have been proposed and combined with other previouly developed methods to establish an ULPH single-phase flow model. The main novelties of these techniques are the derivation of the density diffusive term in the continuum equation inspired by delta-SPH to eliminate pressure oscillations, and the proposal of a new free-surface search algorithm to determine the particles and their normal vectors at the free surface. The ULPH is a nonlocal fluid dynamics model, which is in fact a prototype of Peridynamics in fluid mechanics. Considering the nature of free-surface fluid flows, we strategically implement the diagonalization and renormalization of the shape tensor for particles located in close proximity to the free-surface region to improve the numerical stability of computations. Several complex free-surface flow benchmark examples have been simulated, which confirms that the enhanced treatment techniques can effectively capture the details of surface flow evolution and maintain long-term stability. Moreover, the qualitative and quantitative analyses of the results indicate that the proposed ULPH surface flow model is highly accurate and stable for simulating complex free-surface fluid flows

    Star Polycation Mediated dsRNA Improves the Efficiency of RNA Interference in Phytoseiulus persimilis

    No full text
    RNA interference (RNAi) is one of the most widely used techniques to study gene functions. There is still a lack of RNAi techniques that can be applied in Phytoseiidae conveniently and efficiently. Star Polycation is a new nanomaterial commonly used as a carrier of dsRNA in RNAi. Five genes of P. persimilis (PpATPb, PpATPd, PpRpL11, PpRpS2, and Pptra-2) were selected to verify whether SPc promotes the delivery of dsRNA into P. persimilis through soaking. When each of the five genes were interfered using SPc-mediated dsRNA, the total number of success offspring produced per female in six days decreased by ca. 92%, 92%, 91%, 96%, and 64%. When PpATPb, PpATPd, PpRpL11, or PpRpS2 was interfered, both the fecundity and egg hatching rate decreased. In contrast, when Pptra-2 was interfered, reduction in the reproductive capability was mainly the result of the decreased egg hatching rate. Correspondingly, when the target gene was interfered, P. persimilis expression of PpRpL11 reduced by 63.95%, while that of the other four genes reduced by at least 80%. Our studies showed that nanomaterials, such as SPc, have the potential to be used in RNA interference of phytoseiid mites

    Fundamental study of in-situ strengthening and formation of continuous gradient titanium alloys via laser directed energy deposition

    No full text
    Current heterostructured materials have significant potential for improving the strength-ductility trade-off, but the interfacial bonding capabilities are limited. In this research, composites with TiN/Ti6Al4V interlayer structure were in-situ synthesized by atmospheric remelting using laser directed energy deposition (LDED). The elemental diffusion, microstructure, and mechanical properties of TiN/Ti6Al4V interlayer structure composites were investigated. The mechanical properties of the composites were improved after nitrogen remelting due to the strengthening of internal TiN ceramic particles. The microhardness of TiN/Ti6Al4V composites increased by up to 209.8% to 1141 HV0.2, ultimate tensile strength by 6% and elongation by 34.5% to 1071.4 MPa and 15.6%, respectively. This research demonstrates that a flexible combination of the LDED process and reaction atmosphere can synthesize new periodic layered ceramic/metal composites with excellent mechanical properties. This research offers the groundwork for the fabrication of in-situ strengthening continuous gradient materials

    Transcriptome Analysis of the Innate Immunity-Related Complement System in Spleen Tissue of Ctenopharyngodon idella Infected with Aeromonas hydrophila.

    No full text
    The grass carp (Ctenopharyngodon idella) is an important commercial farmed herbivorous fish species in China, but is susceptible to Aeromonas hydrophila infections. In the present study, we performed de novo RNA-Seq sequencing of spleen tissue from specimens of a disease-resistant family, which were given intra-peritoneal injections containing PBS with or without a dose of A. hydrophila. The fish were sampled from the control group at 0 h, and from the experimental group at 4, 8, 12, 24, 48 and 72 h. 122.18 million clean reads were obtained from the normalized cDNA libraries; these were assembled into 425,260 contigs and then 191,795 transcripts. Of those, 52,668 transcripts were annotated with the NCBI Nr database, and 41,347 of the annotated transcripts were assigned into 90 functional groups. 20,569 unigenes were classified into six main categories, including 38 secondary KEGG pathways. 2,992 unigenes were used in the analysis of differentially expressed genes (DEGs). 89 of the putative DEGs were related to the immune system and 41 of them were involved in the complement and coagulation cascades pathway. This study provides insights into the complement and complement-related pathways involved in innate immunity, through expression profile analysis of the genomic resources in C. idella. We conclude that complement and complement-related genes play important roles during defense against A. hydrophila infection. The immune response is activated at 4 h after the bacterial injections, indicating that the complement pathways are activated at the early stage of bacterial infection. The study has improved our understanding of the immune response mechanisms in C. idella to bacterial pathogens

    Calcium ionophore improves embryonic development and pregnancy outcomes in patients with previous developmental problems in ICSI cycles

    No full text
    Abstract Background Calcium (Ca2+) ionophores are now mainly considered as efficient treatments for fertilization failure. Recently, its application for rescuing poor embryo development was proposed but still non-routine. This study aimed to explore whether Ca2+ ionophore improves embryo development and pregnancy outcomes in patients with poor embryo development in previous intracytoplasmic sperm injection (ICSI) cycles. Methods This study included 97 patients undergoing assisted oocyte activation (AOA) with Ca2+ ionophore (calcimycin, A23187) treatment. Preimplantation embryonic development and clinical outcomes were compared between ICSI-AOA cycles (AOA group) and previous ICSI cycles of the same patients in which poor embryo developmental potential was present (non-AOA group). Subgroups stratified by maternal age (< 35, 35–40, ≥ 40 years, respectively) were analyzed separately. Results A total of 642 MII oocytes were collected in AOA group, and 689 in non-AOA group. Significantly higher day 3 good quality embryo rate (P = 0.034), good quality blastocyst formation rate (P <  0.001), and utilization rate (P <  0.001) were seen in AOA group. Similar results were seen in each subgroup. For pregnancy outcomes, there were significant differences in clinical pregnancy rate (P = 0.039) and live birth rate (P = 0.045) in total group. In subgroup aged < 35 years, biochemical (P = 0.038), clinical (P = 0.041), and ongoing pregnancy rate (P = 0.037) in AOA group were significantly higher than that in non-AOA group. No significant improvement for clinical outcomes for subgroups aged 35–40 and aged ≥40. Conclusion The study suggests that calcimycin could improve preimplantation development and pregnancy outcomes in patients aged < 35 years with embryo developmental problems in previous ICSI cycles

    Effects of dietary polyherbal mixtures on growth performance, antioxidant capacity, immune function and jejunal health of yellow-feathered broilers

    No full text
    ABSTRACT: This study aimed to investigate the effects of polyherbal mixtures (PHM) on growth performance, antioxidant capacities, immune function, and intestinal health in yellow-feathered broilers. PHM is composed of five traditional Chinese medicine herbs (Portulaca oleracea L., Radix Sophora flavescens, Thalictrum glandulosissimum, Terra flava usta, and Pogostemon cablin). A total of 270 one-day-old yellow-feathered broilers were randomly allotted into 3 treatments for a 42-d feeding trial, each with 6 replicates of 15 birds. The dietary treatments consisted of a basal diet (CON), a basal diet supplemented with 50 mg/kg chlortetracycline (CTC), and a basal diet supplemented with 1000 mg/kg PHM. The results showed that dietary PHM supplementation increased body weight, ADG, and decreased F/G compared to the CON. PHM also increased spleen index and mRNA expression of IL-4 (d 21), and thymus index, serum IgA (d 42) and IgG, IL-4 and sIgA in jejunal mucosa (d 21 and 42), but decreased serum IFN-γ and mRNA expression of IFN-γ (d 21 and 42). In addition, PHM increased serum SOD, GSH-Px (d 21 and 42) and T-AOC (d 42), but decreased the content of serum MDA (d 21), the up-regulated mRNA expression of GSH-Px, CAT (d 21), SOD and CAT (d 42). Furthermore, PHM also improved the intestinal epithelial barrier indicators by the up-regulated mRNA expression of CLDN-1, OCLN (d 21 and 42) and ZO-1 (d 21), and the increased of villus height and villus height to crypt depth in jejunum (d 42). The high-throughput sequencing results showed that dietary PHM supplementation increased the alpha diversity and relative abundance of Oscillospira and Ruminococcus (d 21) and Lactobacillus (d 42), whereas decreasing that of Enterococcus (d 21) compared with CON. PICRUSt analysis revealed that metabolic pathways of carbohydrate, energy, lipid, cofactors, and vitamins were significantly enriched in the PHM group. Spearman's correlation analysis revealed that the genera Lactobacillus, Enterococcus, Ruminococcus, Oscillospira, and Faecalibacterium were related to growth performance, intestinal integrity, immune-related factors, antioxidant indices, and tight junction proteins. In conclusion, the results indicated that dietary PHM supplementation improved growth performance and immune status of yellow-feathered broilers by enhancing antioxidant capacities, barrier function, and modulated jejunal microbial communities. PHM used in our study has the potential to replace prophylactic antibiotic use in poultry production systems

    Insulin-Attenuated Inflammatory Response of Dendritic Cells in Diabetes by Regulating RAGE-PKCβ1-IRS1-NF-κB Signal Pathway: A Study on the Anti-Inflammatory Mechanism of Insulin in Diabetes

    No full text
    Background. Diabetes is associated with chronic inflammation, and dendritic cells (DCs) have proinflammatory effect in diabetes. The anti-inflammatory effect of insulin on diabetes is not entirely clear. The study aims to examine insulin-induced effects on the inflammatory response in DCs. Methods. Twenty-one C57BL/6 mice were divided into 3 groups. Streptozotocin was injected into the diabetic mice model. The bone marrow-derived DCs (BMDCs) were obtained from C57BL/6 mice. CD83, CD86, and type II major histocompatibility complex (MHC-II) of BMDCs were measured by flow cytometry. The fluctuations in the RNA levels of cytokines and chemokines were analyzed by quantitative RT-PCR. The concentrations of IFN-γ and TNF-α were calculated using ELISA kits, and the proteins were detected using western blot. Results. In CD11c+ DCs derived from the spleens with hyperglycemia, the expression of CD83 and CD86 in diabetic mice was significantly upregulated, coupled with a higher secretion level of cytokines and chemokines, and increased phosphorylation of NF-κB and IκB. Insulin therapy was found to have a reversal effect on the inflammatory response and immune maturation in DCs. In AGEs-BSA-stimulated BMDCs, insulin repressed the immune maturation and downregulated the expression of RAGE, phospho-PKCβ1, and serine phospho-IRS1 in an adose-dependent manner. Such effects can be abolished by PMA, but not IR-neutralizing antibody. AGEs-BSA-induced BMDCs immune maturation was inhibited by the neutralizing antibody of RAGE, the PKCβ1 inhibitor, or the IRS1 siRNA. Conclusions. Insulin has the capability of attenuating the inflammatory response of DCs in diabetes, partly through the downregulation of RAGE expression followed by the inhibition of PKCβ1 phosphorylation and IRS1 serine phosphorylation, resulting in the inactivation of IR binding-independent NF-κB. This might partly explain the antiatherogenic effect of insulin on diabetes
    corecore