156 research outputs found
Fast finite element stress and deformation prediction for large thick-wall welded cylinder with angle-inserting elbow
Cultivation and Characterization of Pulmonary Microvascular Endothelial Cells from Chicken Embryos
To improve the understanding on the biological properties of endothelial cells (ECs), a method for the isolation and identification in vitro culture of avian pulmonary microvascular endothelial cells (PMVECs) is described. The isolated and cultured cells from chick embryos were identified by cellular morphology and immunocytochemistry. The results showed that the cultured cells exhibited typical cobblestone morphology viewed under an inverted microscope; and were bound with Bandeiraea simplicifolia lectin and stained positive for CD31 and factor VIII-related antigen. In conclusion, the findings of present study for the isolation and cultivation of PMVECs may allow more detailed analysis of their biological properties, and provide a valuable model for studying pathological processes including pulmonary hypertension, ascites and pulmonary vascular remodeling in broiler chickens
Effects of Topography on Tree Community Structure in a Deciduous Broad-Leaved Forest in North-Central China
Topography strongly influences the compositional structure of tree communities and plays a fundamental role in classifying habitats. Here, data of topography and 16 dominant tree species abundance were collected in a fully mapped 25-ha forest plot in the Qinling Mountains of north-central China. Multivariate regression trees (MRT) were used to categorize the habitats, and habitat associations were examined using the torus-translation test. The relative contributions of topographic and spatial variables to the total community structure were also examined by variation partitioning. The results showed the inconsistency in association of species with habitats across life stages with a few exceptions. Topographic variables [a + b] explained 11% and 19% of total variance at adult and juvenile stage, respectively. In contrast, spatial factors alone [c] explained more variation than topographic factors, revealing strong seed dispersal limitation in species composition in the 25-ha forest plot. Thus, the inconsistent associations of species and habitats coupled with high portion of variation of species composition explained by topographic and spatial factors might suggest that niche process and dispersal limitation had potential influences on species assemblage in the deciduous broad-leaved forest in north-central China
Learning to Select Cuts for Efficient Mixed-Integer Programming
Cutting plane methods play a significant role in modern solvers for tackling
mixed-integer programming (MIP) problems. Proper selection of cuts would remove
infeasible solutions in the early stage, thus largely reducing the
computational burden without hurting the solution accuracy. However, the major
cut selection approaches heavily rely on heuristics, which strongly depend on
the specific problem at hand and thus limit their generalization capability. In
this paper, we propose a data-driven and generalizable cut selection approach,
named Cut Ranking, in the settings of multiple instance learning. To measure
the quality of the candidate cuts, a scoring function, which takes the
instance-specific cut features as inputs, is trained and applied in cut ranking
and selection. In order to evaluate our method, we conduct extensive
experiments on both synthetic datasets and real-world datasets. Compared with
commonly used heuristics for cut selection, the learning-based policy has shown
to be more effective, and is capable of generalizing over multiple problems
with different properties. Cut Ranking has been deployed in an industrial
solver for large-scale MIPs. In the online A/B testing of the product planning
problems with more than variables and constraints daily, Cut Ranking has
achieved the average speedup ratio of 12.42% over the production solver without
any accuracy loss of solution.Comment: Paper accepted at Pattern Recognition journa
Hydrodynamic Delivery of Chitosan-Folate-DNA Nanoparticles in Rats with Adjuvant-Induced Arthritis
50 kDa chitosan was conjugated with folate, a specific tissue-targeting ligand. Nanoparticles such as chitosan-DNA and folate-chitosan-DNA were prepared by coacervation process. The hydrodynamic intravenous injection of nanoparticles was performed in the right posterior paw in normal and arthritic rats. Our results demonstrated that the fluorescence intensity of DsRed detected was 5 to 12 times more in the right soleus muscle and in the right gastro muscle than other tissue sections. β-galactosidase gene expression with X-gal substrate and folate-chitosan-plasmid nanoparticles showed best coloration in the soleus muscle. Treated arthritic animals also showed a significant decrease in paw swelling and IL-1β and PGE2 concentration in serum compared to untreated rats. This study demonstrated that a nonviral gene therapeutic approach using hydrodynamic delivery could help transfect more efficiently folate-chitosan-DNA nanoparticles in vitro/in vivo and could decrease inflammation in arthritic rats
Efficient Nonviral Gene Therapy Using Folate-Targeted Chitosan-DNA Nanoparticles In Vitro
Nonviral cationic polymers like chitosan can be combined with DNA to protect it from degradation. The chitosan is a biocompatible, biodegradable, nontoxic, and cheap polycationic polymer with low immunogenicity. The objective of this study was to synthesize and then assess different chitosan-DNA nanoparticles and to select the best ones for selective in vitro transfection in human epidermoid carcinoma (KB) cell lines. It revealed that different combinations of molecular weight, the presence or absence of folic acid ligand, and different plasmid DNA sizes can lead to nanoparticles with various diameters and diverse transfection efficiencies. The intracellular trafficking, nuclear uptake, and localization are also studied by confocal microscopy, which confirmed that DNA was delivered to cell nuclei to be expressed
Gene expression differences between Crohn's disease aphthous ulcers and healthy Peyer's patches highlight novel therapeutic targets
Background and Aim: The earliest macroscopic lesion in Crohn’s disease(CD) is the aphthous ulcer, which overlies Peyer’s patches and lymphoidfollicles. Our aim was to characterize differences in gene expression andthe virome of aphthous ulcers and Peyer’s patches.Methods: Biopsies (n = 24) were obtained from the terminal ileum of 12patients (six with CD and six healthy controls). Aphthous ulcers and adja-cent unaffected mucosa were obtained from patients with CD, and Peyer’spatches and adjacent mucosa from the controls. All patients, except one,were medication free. RNA was extracted using Qiagen kits. NextSeq500 libraries were constructed using NextSeq 500/550 High output kits(Illumina) in a 150 bp paired-end format. Whole genome transcripts wereassessed for quality using FASTQC, trimmed using Trimmomatic, andaligned to the human reference genome using subread mapper. Fragmentcounts were obtained using featureCount, and expression values normal-ized using the trimmed mean of M-values normalization method (TMM).Differential gene expression analyses were performed using generalizedlinear models in edgeR. Cell-specific gene expression was determinedusing ImSig. Reads that did not map to the human genome were used tomine for virus sequences using the VirusSeeker pipeline.Results: We obtained 36 million tags per sample, 87% were retained fordownstream processing, and 93% of these mapped to the human genome.A total of 920 genes were significantly differentially expressed betweenaphthous ulcers and Peyer’s patches (P = <0.001); all were upregulatedin aphthous ulcers. Differential gene expression analysis revealed 34 path-ways that were upregulated in aphthous ulcers relative to Peyer’s patches.Pathways that were over-expressed included those involved in respondingto bacteria, leukocyte chemotaxis, inflammatory response, and creation ofC2 and C4 activators. Receptors for the constant region of IgG were repre-sented in 13 pathways. The cytokine OSM and its receptor (OSMR) werealso over-expressed in aphthous ulcers. ImSig, which is capable of usingtranscriptome data to indicate cell types and their activation state, revealedthat core marker genes for plasma cells were overrepresented in aphthousulcers relative to Peyer’s patches and unaffected or normal mucosa. Therewas no virus common to all aphthous ulcers. We detected human herpesvirus 4 in one aphthous ulcer, human herpes virus 1 in mucosa from apatient with CD, and a novel Totivirus in mucosa of one control patient.Conclusions: A number of gene clusters and immune pathways are over-expressed in aphthous ulcers compared with Peyer’s patches. These bio-logically relevant gene lists highlight a number of new therapeutic targetsand potential biomarkers for early stage disease. Viruses are an unlikelyinitiator of C
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