Effect of Lipopolysaccharide (LPS) and Outer Membrane Protein (OMP) Vaccines on Protection of Grass Carp (Ctenopharyngodon idella) against Aeromonas hydrophila

Abstract The gram-negative bacterium, Aeromonas hydrophila, causes high mortality and economic losses to the aquaculture industry. We investigated whether lipopolysaccharide (LPS) or outer membrane proteins (OMP) from A. hydrophila can enhance specific and/or non-specific immunity in grass carp (Ctenopharyngodon idella). Fish were injected intraperitoneally with LPS, OMP, or formalin-killed cells (FKC) from A. hydrophila. The control group was injected with phosphate buffered saline (PBS). All three antigens elicited strong immune responses. Respiratory burst and phagocytic activities in head kidney leukocytes and serum lysozyme activity peaked on day 21 after vaccination. Heavy chain gene transcription of immunoglobulin M and Z in the head kidney in vaccinated fish peaked on day 28. Relative percent survival was 83.3%, 72.2%, and 55.6% in the LPS, OMP, and FKC groups, respectively, but only 10% in control fish. Results suggest that LPS and OMP isolated from A. hydrophila can enhance specific immunity, non-specific immunity, and protection against A. hydrophila in fish. Thus, LPS and OMP could be important antigens for development of vaccines to control diseases caused by A. hydrophila in grass carp and other aquatic animals

A Survey of Source Code Search: A 3-Dimensional Perspective

(Source) code search is widely concerned by software engineering researchers because it can improve the productivity and quality of software development. Given a functionality requirement usually described in a natural language sentence, a code search system can retrieve code snippets that satisfy the requirement from a large-scale code corpus, e.g., GitHub. To realize effective and efficient code search, many techniques have been proposed successively. These techniques improve code search performance mainly by optimizing three core components, including query understanding component, code understanding component, and query-code matching component. In this paper, we provide a 3-dimensional perspective survey for code search. Specifically, we categorize existing code search studies into query-end optimization techniques, code-end optimization techniques, and match-end optimization techniques according to the specific components they optimize. Considering that each end can be optimized independently and contributes to the code search performance, we treat each end as a dimension. Therefore, this survey is 3-dimensional in nature, and it provides a comprehensive summary of each dimension in detail. To understand the research trends of the three dimensions in existing code search studies, we systematically review 68 relevant literatures. Different from existing code search surveys that only focus on the query end or code end or introduce various aspects shallowly (including codebase, evaluation metrics, modeling technique, etc.), our survey provides a more nuanced analysis and review of the evolution and development of the underlying techniques used in the three ends. Based on a systematic review and summary of existing work, we outline several open challenges and opportunities at the three ends that remain to be addressed in future work.Comment: submitted to ACM Transactions on Software Engineering and Methodolog

Effect of Lipopolysaccharide (LPS) and Outer Membrane Protein (OMP) Vaccines on Protection of Grass Carp (Ctenopharyngodon idella) against Aeromonas hydrophila

The gram-negative bacterium, Aeromonas hydrophila, causes high mortality and economic losses to the aquaculture industry. We investigated whether lipopolysaccharide (LPS) or outer membrane proteins (OMP) from A. hydrophila can enhance specific and/or non-specific immunity in grass carp (Ctenopharyngodon idella). Fish were injected intraperitoneally with LPS, OMP, or formalin-killed cells (FKC) from A. hydrophila. The control group was injected with phosphate buffered saline (PBS). All three antigens elicited strong immune responses. Respiratory burst and phagocytic activities in head kidney leukocytes and serum lysozyme activity peaked on day 21 after vaccination. Heavy chain gene transcription of immunoglobulin M and Z in the head kidney in vaccinated fish peaked on day 28. Relative percent survival was 83.3%, 72.2%, and 55.6% in the LPS, OMP, and FKC groups, respectively, but only 10% in control fish. Results suggest that LPS and OMP isolated from A. hydrophila can enhance specific immunity, non-specific immunity, and protection against A. hydrophila in fish. Thus, LPS and OMP could be important antigens for development of vaccines to control diseases caused by A. hydrophila in grass carp and other aquatic animals

The Modular Gait Design of a Soft, Earthworm-like Locomotion Robot Driven by Ultra-Low Frequency Excitation

In complex and extreme environments, such as pipelines and polluted waters, gait programming has great significance for multibody segment locomotion robots. The earthworm-like locomotion robot is a representative multibody bionic robot, which has the characteristics of low weight, multibody segments, and excellent movement performance under the designed gait. The body segment cell can realize large deformation under ultra-low frequency excitation. The multibody segment robot can locomote under ultra-low frequency excitation with appropriate shifts. In this paper, a modular gait design principle for a soft, earthworm-like locomotion robot is proposed. The driven modules defined by modular gait generation correspond to the peristaltic wave transmissions of the excitation in the robot for different modular gait modes. A locomotion algorithm is presented to simulate the locomotion of the earthworm-like robot under different locomotion gaits. Moreover, the locomotion speeds are obtained for different modular gait modes. The results show that locomotion speed is related to the original state of the body segments and modular gaits. As the initial actuated segments and driven modules (which correspond to the excitation frequency and shift) increase, faster movement speeds can be realized, which resolves the speed saturation of the earthworm-like robot. The proposed modular gait design method gives a new gait generation principle for the improvement of the locomotion performance of soft, earthworm-like robots

Dynamic balancing of intestinal short-chain fatty acids: the crucial role of bacterial metabolism

Background: Short-chain fatty acids (SCFAs) play important physiological roles in human health. Adverse effects on health are known with a low or excessive concentration of SCFAs although the optimal level of SCFAs in the body is unknown yet. The level of endogenous SCFAs is affected by many factors of which gut bacteria are the most important one. However, how gut bacteria and a dietary intervention affect SCFA balance in the gut still needs to be clarified.Scope and approach: In addition to addressing the importance of a dynamic balance of SCFAs for health, we discuss the factors affecting the dynamic balance of SCFAs, especially the gut SCFA-producing bacteria, including the classification of the bacteria, their response to diet, the SCFAs metabolic pathways and the catalytic mechanisms of the main rate-limiting enzymes.Key findings and conclusions: SCFAs levels can be regulated endogenously and exogenously. Exogenous regulation delivers SCFAs to gut by esterification with dietary fibres. Endogenous regulation like diet, directly or indirectly affect gut microbiota, including their abundance, fitness and SCFAs production. Until now, 74 bacterial species are reported to produce SCFAs, the metabolic pathways are classified into 4 categories, and the 4 rate-limiting enzymes in the metabolic pathways are summarized. We also propose methods for long-lasting endogenous SCFAs balancing, including identifying the minimum sets of SCFA-producing bacterial group, and possible dietary intervention to form a minimum group of gut microbiota for SCFAs synthesis. An integrated approach will help realize the rational regulation of balanced SCFAs levels to benefit human health

Dynamic Modeling and Model-Based Control with Neural Network-Based Compensation of a Five Degrees-of-Freedom Parallel Mechanism

In this paper, a spatial parallel mechanism with five degrees of freedom is studied in order to provide a promising dynamic model for the control design. According to the inverse kinematics of the mechanism, the dynamic model is derived by using the Lagrangian method, and the co-simulation using MSC ADAMS and MATLAB/Simulink is adopted to verify the established dynamic model. Then the pre-trained deep neural network (DNN) is introduced to predict the real-time state of the end-effector of the mechanism. Compared to the traditional Newton’s method, the DNN method reduces the cost of the forward kinematics calculation while ensuring prediction accuracy, which enables the dynamic compensation based on feedback signals. Furthermore, the computed torque control with DNN-based feedback compensation is implemented for the trajectory tracking of the mechanism. The simulations show that, in the most complicated case that involves friction and external disturbance, the proposed controller has better tracking performance. The results indicate the necessity of dynamic modeling in the design of control with high precision