Parallel Contour Path Planning for Complicated Cavity Part Fabrication using Voronoi-based Distance Map

To generate parallel contour path for direct production of complicated cavity component, a novel path planning based on Voronoi-based distance map is presented in this paper. Firstly, the grid representation of polygonal slice is produced by hierarchical rasterization using graphics hardware acceleration and divided into Voronoi cells of contour by an exact EDT (Euclidean distance transformation). Then, each VCI (Voronoi cell of inner contour) is further subdivided into CLRI (closed loop region of inner contour) and OLRI (open loop region of inner contour). Closed paths for each CLRI and the block merging VCO (Voronoi cell of outer contour) and all OLRIs are generated by local and global isoline extraction, respectively. The final path ordered in circumferential and radial directions is obtained by sorting and connecting all individual paths. In comparison with conventional methods such as pair-wise intersection and Voronoi diagram, the proposed algorithm is numerically robust, can avoid null path and self-intersection because of the application of distance map and discrete Voronoi diagram. It is especially used for FGM (Functionally Graded Material) design and fabrication.Mechanical Engineerin

Adaptive Slicing for Multi-Axis Hybrid Plasma Deposition and Milling

Hybrid Plasma Deposition and Milling (HPDM), a five-axis manufacturing system integrated material additive and subtractive processes, can be used to create overhang metallic components directly without the usage of sacrificial support structure. Different from conventional slicing methods, a new slicing algorithm with changeable direction and thickness is proposed in this paper. Minimal overhang length is selected as the objective function to optimize the build direction. The thickness is adjusted to meet allowable overhang length and allowable cups height. The input mesh is first decomposed into non-uniform thickness segment meshes and then each segment is cut into uniform thickness slices. The output slices consist of split slices between two adjacent segment meshes and inner slices for each segment mesh. Examples and analyses confirm the feasibility and effectiveness.Mechanical Engineerin

Research on Microstructure and Properties of Medium Carbon Steel Parts Manufactured by HDMR Technology

A new study on manufacturing medium carbon steel parts by HDMR (Hybrid Deposition and Micro Rolling) technology was carried out, and the microstructures and mechanical properties obtained by HDMR process and freeform arc deposition process respectively were tested and compared in this paper. The experiment results show that: compared with the freeform arc deposition process, the grain size number obtained by HDMR process increased from 3.0 to 9.0；the tensile strength and yield strength were increased by 37.1%, 68.6%，in contrast to the investment casting, increased by 65.4% and 107.7%; compared with the forging, the tensile strength and yield strength were increased by 12.9% and 31.4% respectively. Finally, a medium carbon 45 steel aeronautical part difficult to overlay was manufactured successfully by HDMR technology, thus a new efficient way for additive manufacturing of hard-shaping metal parts at high-quality with low-cost was provided.Mechanical Engineerin

Types and distribution of mucous cells of the abalone Haliotis diversicolor

The types and distribution of mucous cells of Haliotis diversicolorwere observed and analyzed using the alcian blue and periodic acid schiffs (AB-PAS) reaction and histological procedures. According to the color of the mucous cells, they were divided into four types: Type I, pure red; type II, pure blue; type III, purple reddish; type IV, blue purple. Most of the mucous cells in the mantle were type II, with cup- or stick-like shape. Gill axis and gill filament epithelia were rich in mucous cells and most of them were type II and III, with circle-, cup- and stick-like shapes. There were a few mucous cells in the pedal epithelia, mainly type II, whereas, the pedal gland had a great density of mucous cells, which were large or small and mainly type II and IV. There were many mucous cells in the epithelia around the mouth, most of which were medium-sized cup-shaped type II. In the esophagus, the number of mucous cells decreased gradually from the anterior to posterior, whereas in the distal intestine mucous cells, there were more than in the proximal one and they were more cup–shaped and circle–shaped, mainly type II.Keywords: Haliotis diversicolor; mucous cells, types, distributio

Bacillus cereus, a potential pathogen of snakehead fish Ophiocephalus argus

Bacillus cereus is an emerging pathogen that has caused high mortalities in aquaculture animals. Yet the pathogenicity of B. cereus in snakehead fish Ophiocephalus argus is still unclear. In this study, a virulent strain (CA4) was isolated from diseased snakehead fish suffering from a typical symptom of hepatic hemorrhage with blood vessel congestion and macrophage infiltration, and was identified molecularly and phenotypically as B. cereus. It was β-hemolytic, showed an LD50 value of 2.57×106 CFU mL-1 for snakehead fish, and developed multiple resistances to cotrimoxazole, doxycycline, florfenicol, neomycin, sulfisoxazole, and tetracycline in aquaculture use. To the best of our knowledge, this is the first report of snakehead fish- pathogenic B. cereus. The findings of this study provide new insights into the potential threat of pathogenic B. cereus to snakehead fish

Identifying Subgroups of ICU Patients Using End-to-End Multivariate Time-Series Clustering Algorithm Based on Real-World Vital Signs Data

This study employed the MIMIC-IV database as data source to investigate the use of dynamic, high-frequency, multivariate time-series vital signs data, including temperature, heart rate, mean blood pressure, respiratory rate, and SpO2, monitored first 8 hours data in the ICU stay. Various clustering algorithms were compared, and an end-to-end multivariate time series clustering system called Time2Feat, combined with K-Means, was chosen as the most effective method to cluster patients in the ICU. In clustering analysis, data of 8,080 patients admitted between 2008 and 2016 was used for model development and 2,038 patients admitted between 2017 and 2019 for model validation. By analyzing the differences in clinical mortality prognosis among different categories, varying risks of ICU mortality and hospital mortality were found between different subgroups. Furthermore, the study visualized the trajectory of vital signs changes. The findings of this study provide valuable insights into the potential use of multivariate time-series clustering systems in patient management and monitoring in the ICU setting.Comment: Proceedings of Beijing Health Data Science Summit (HDSS) 202

Helicobacter zhangjianzhongii sp. nov., isolated from dog feces

In 2019, two distinct bacterial isolates were independently isolated from the fecal samples of separate dogs in Beijing, China. These cells exhibit microaerobic, are Gram-negative, motile, and possess a characteristic spiral shape with bipolar single flagellum. They display positive results for the oxidase test while being negative for both catalase and urease. These organisms measure approximately 0.2–0.3 μm in width and 4.5–6 μm in length. The colonies are wet, flat, grey, circular, and smooth with sizes ranging from 1 to 2 mm in diameter after 2 days of growth. However, strains may exhibit variations in size and morphology following extended incubation. Phylogenetic analyses based on the 16S rRNA gene and core genome indicated that these two isolates belong to the genus Helicobacter and formed a robust clade that was remains distinctly separate from currently recognized species. These two isolates shared low dDDH relatedness and ANI values with their closest species Helicobacter canis CCUG 32756T, with these values falling below the commonly cutoff values for strains of the same species. The genomic DNA G + C contents of strain XJK30-2 were 44.93 mol%. Comparing the phenotypic and phylogenetic features between these two isolates and their closely related species, XJK30-2 represents a novel species within the genus Helicobacter, for which the name Helicobacter zhangjianzhongii sp. nov. (Type strain XJK30-2T = GDMCC 1.3695T) is proposed

Morphologic, cytometric, quantitative transcriptomic and functional characterisation provide insights into the haemocyte immune responses of Pacific abalone (Haliotis discus hannai)

In recent years, the abalone aquaculture industry has been threatened by the bacterial pathogens. The immune responses mechanisms underlying the phagocytosis of haemocytes remain unclear in Haliotis discus hannai. It is necessary to investigate the immune mechanism in response to these bacterial pathogens challenges. In this study, the phagocytic activities of haemocytes in H. discus hannai were examined by flow cytometry combined with electron microscopy and transcriptomic analyses. The results of Vibrio parahaemolyticus, Vibrio alginolyticus and Staphylococcus aureu challenge using electron microscopy showed a process during phagosome formation in haemocytes. The phagocytic rate (PP) of S. aureus was higher than the other five foreign particles, which was about 63%. The PP of Vibrio harveyi was about 43%, the PP peak of V. alginolyticus in haemocyte was 63.7% at 1.5 h. After V. parahaemolyticus and V. alginolyticus challenge, acid phosphatase, alkaline phosphatase, total superoxide dismutase, lysozyme, total antioxidant capacity, catalase, nitric oxide synthase and glutathione peroxidase activities in haemocytes were measured at different times, differentially expressed genes (DEGs) were identified by quantitative transcriptomic analysis. The identified DEGs after V. parahaemolyticus challenge included haemagglutinin/amebocyte aggregation factor-like, supervillin-like isoform X4, calmodulin-like and kyphoscoliosis peptidase-like; the identified DEGs after V. alginolyticus challenge included interleukin-6 receptor subunit beta-like, protein turtle homolog B-like, rho GTPase-activating protein 6-like isoform X2, leukocyte surface antigen CD53-like, calponin-1-like, calmodulin-like, troponin C, troponin I-like isoform X4, troponin T-like isoform X18, tumor necrosis factor ligand superfamily member 10-like, rho-related protein racA-like and haemagglutinin/amebocyte aggregation factor-like. Some immune-related KEGG pathways were significantly up-regulated or down-regulated after challenge, including thyroid hormone synthesis, Th17 cell differentiation signalling pathway, focal adhesion, melanogenesis, leukocyte transendothelial migration, inflammatory mediator regulation of TRP channels, ras signalling pathway, rap1 signalling pathway. This study is the first step towards understanding the H. discus hannai immune system by adapting several tools to gastropods and providing a first detailed morpho-functional study of their haemocytes