217 research outputs found
Analytical and experimental investigation on eigenfrequency-based damage diagnosis of cantilever beam
This paper presents two eigenfrequency-based damage diagnosis methods in a cantilever beam. The analytical relationship has been established between the eigenfrequency and damage parameters, including relative damage location and severity. On the premise that pre-damaged eigenfrequencies are known, a diagnosis algorithm without requirement of material properties is proposed based on change ratios of the first three eigenfrequencies. If pre-damaged eigenfrequencies are unfeasible to be acquired, a three-contour method based on only post-damaged eigenfrequencies is introduced to estimate damage parameters. The uniqueness of solution is discussed. Both the numerical simulation by the finite element method and the experiment on real beams are conducted and result in a good agreement between actual damage parameters and calculated values by using the proposed methods
Understanding Haemophilus parasuis infection in porcine spleen through a transcriptomics approach
<p>Abstract</p> <p>Background</p> <p><it>Haemophilus parasuis </it>(HPS) is an important swine pathogen that causes Glässer's disease, which is characterized by fibrinous polyserositis, meningitis and arthritis. The molecular mechanisms that underlie the pathogenesis of the disease remain poorly understood, particularly the resistance of porcine immune system to HPS invasion. In this study, we investigated the global changes in gene expression in the spleen following HPS infection using the Affymetrix Porcine Genechip™.</p> <p>Results</p> <p>A total of 931 differentially expressed (DE) transcripts were identified in the porcine spleen 7 days after HPS infection; of these, 92 unique genes showed differential expression patterns based on analysis using BLASTX and Gene Ontology. The DE genes involved in the immune response included genes for inflammasomes (<it>RETN</it>, <it>S100A8</it>, <it>S100A9</it>, <it>S100A12</it>), adhesion molecules (<it>CLDN3</it>, <it>CSPG2</it>, <it>CD44</it>, <it>LGALS8</it>), transcription factors (<it>ZBTB16</it>, <it>SLC39A14</it>, <it>CEBPD</it>, <it>CEBPB</it>), acute-phase proteins and complement (<it>SAA1</it>, <it>LTF</it>, <it>HP</it>, <it>C3</it>), differentiation genes for epithelial cells and keratinocytes (<it>TGM1</it>, <it>MS4A8B</it>, <it>CSTA</it>), and genes related to antigen processing and presentation (<it>HLA-B</it>, <it>HLA-DRB1</it>). Further immunostimulation analyses indicated that mRNA levels of <it>S100A8</it>, <it>S100A9</it>, and <it>S100A12 </it>in porcine PK-15 cells increased within 48 h and were sustained after administration of lipopolysaccharide (LPS) and Poly(I:C) respectively. In addition, mapping of DE genes to porcine health traits QTL regions showed that 70 genes were distributed in 7 different known porcine QTL regions. Finally, 10 DE genes were validated by quantitative PCR.</p> <p>Conclusion</p> <p>Our findings demonstrate previously unrecognized changes in gene transcription that are associated with HPS infection <it>in vivo</it>, and many potential cascades identified in the study clearly merit further investigation. Our data provide new clues to the nature of the immune response in mammals, and we have identified candidate genes that are related to resistance to HPS.</p
Study of transport, tissue distribution, depletion, and hepatotoxicity of Cyadox, a quinoxaline-1,4-dioxide derivative
BackgroundCyadox (CYA) is a derivative of quinoxaline 1,4-dioxide and a safe and effective synthetic antibacterial agent.ObjectiveThis study aimed to explore the drug transport in blood, distribution, depletion and hepatotoxicity of drugs in animals.MethodsThe transport of CYA in blood was studied using fluorescence, circular dichroism (CD) and molecular docking methods. Tissue distribution and depletion of CYA in rats were evaluated following oral administration of [3H]-CYA at different doses. Hepatotoxicity of drugs evaluated by transcriptomics.ResultsDuring transport in the bloodstream, the drug binds to bovine serum albumin (BSA) by hydrogen bonding and has only one binding site. Hydrogen bonds were formed between O (2) of CYA and ARG208, O (3) of CYA and LEU480, VAL481. The secondary protein conformation of BSA changed after binding with an increase in α-helix and a decrease in β-strand. After a single oral administration of [3H]-CYA, it was excreted rapidly within 7 days, with 34.81% from the urine and 60.25% from the feces. Higher and sustained levels of radioactivity were detected in the liver during the post-dose period, suggesting that the drug may concentrate in the liver. The transcriptomic data indicates that CYA exhibits low hepatotoxicity. However, there are indications that it may have an impact on steroid biosynthesis.ConclusionThis study could serve as a basis for conducting further studies on the use of CYA in food animals and improving the pharmacologic, pharmacokinetic, and toxicologic effects of CYA on food animals
Catalyst Composition and Content Effects on the Synthesis of Single-Walled Carbon Nanotubes by Arc Discharge
Single-walled carbon nanotubes (SWCNTs) were prepared by a modified arc discharging furnace using Fe-Ni-Mg powders as catalyst at 600∘C. The effects of catalyst composition and content on the production rate and purity of SWCNTs are investigated in this paper. When the Fe-Ni-Mg catalyst composition is 2: 1: 2 wt% and the catalyst content is 5 wt%, the experimental results indicate that the production of SWCNTs is 12 grams per hour, and the purity and diameter of SWCNTs are 70% and 1.22 ∼1.38 nm, respectively. The results indicate that the cooperative function of catalyst composition and content plays an important role in the production of SWCNTs. The aim of this work is to control the production process of SWCNTs efficiently
The genetic characterization of germplasm and identification of the litter size trait associated candidate genes in Dexin mutton and fine-wool sheep
Xinjiang is a major province of sheep breeding in China, which plays an important role in meeting people’s needs for meat products, increasing farmers’ income and sustainable development of animal husbandry. However, the genetic differentiation relationship between breeds was not clear, and most sheep had low fecundity, which seriously restricted the efficient development of sheep industry. Therefore, this study used the whole genome resequencing to detect the genetic variation of Dexin mutton and fine-wool sheep, explored the selected regions and important genes of the litter size traits, analyzed the genetic mechanism of reproductive traits, and provided new insights for the high fecundity breeding of sheep. A total of 5,236.338 G genome data and 35,884,037 SNPs were obtained. Furthermore, we identified 39 selection signals spanning candidate genes, 99 genes were significantly associated related to growth, reproduction and immunity, among which, BRIP1, BMPR1B, BMP4, NGF, etc. genes, and MAKP signaling pathway, Fanconi anemia pathway and Thyroid hormone signaling pathway and other signaling pathways were significantly correlated with litter size trait. Among them, we identified NGF, TrKA and BRIP1 genes was the important genes for sheep litter size traits and the mutation frequencies of 9 SNPs in BRIP1 gene were significantly different in domestic sheep in the world. The research provided new insights for the breeding of self-cultivated meat fine-wool sheep
Regulation of B-cell development and tolerance by different members of the miR-17∼1/492 family microRNAs
The molecular mechanisms that regulate B-cell development and tolerance remain incompletely understood. In this study, we identify a critical role for the miR-17∼1/492 microRNA cluster in regulating B-cell central tolerance and demonstrate that these miRNAs control early B-cell development in a cell-intrinsic manner. While the cluster member miR-19 suppresses the expression of Pten and plays a key role in regulating B-cell tolerance, miR-17 controls early B-cell development through other molecular pathways. These findings demonstrate differential control of two closely linked B-cell developmental stages by different members of a single microRNA cluster through distinct molecular pathwaysThis study is supported by the PEW Charitable Trusts, Cancer Research Institute, Lupus Research Institute and National Institute of Health (R01AI087634, R01AI089854, R56AI110403 and R56AI121155 to C.X.
Interfacial Interactions and Nanostructure Changes in DPPG/HD Monolayer at the Air/Water Interface
Lung surfactant (LS) plays a crucial role in regulating surface tension during normal respiration cycles by decreasing the work associated with lung expansion and therefore decreases the metabolic energy consumed. Monolayer surfactant films composed of a mixture of phospholipids and spreading additives are of optional utility for applications in lung surfactant-based therapies. A simple, minimal model of such a lung surfactant system, composed of 1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-(1-gylcerol)] (DPPG) and hexadecanol (HD), was prepared, and the surface pressure-area (π-A) isotherms and nanostructure characteristics of the binary mixture were investigated at the air/water interface using a combination of Langmuir-Blodgett (LB) and atomic force microscopy (AFM) techniques. Based on the regular solution theory, the miscibility and stability of the two components in the monolayer were analyzed in terms of compression modulus (Cs-1) , excess Gibbs free energy (ΔGexcπ) , activity coefficients (γ), and interaction parameter (ξ). The results of this paper provide valuable insight into basic thermodynamics and nanostructure of mixed DPPG/HD monolayers; it is helpful to understand the thermodynamic behavior of HD as spreading additive in LS monolayer with a view toward characterizing potential improvements to LS performance brought about by addition of HD to lung phospholipids
A study of multinucleated giant cells in esophageal cancer
Objectives: To evaluate the occurrence, abundance, distribution, nature and clinical significance of multi-nucleated giant cell (MGC) in esophageal cancer. Materials and methods: MGCs were examined with conventional pathology, immunohistochemistry and immunofluorescence in 107 esophageal cancer tissues. The findings were correlated to pathological diagnosis and clinical behavior of the cancers. Results: MGCs were identified in 31.7% (34/107) of the cases. MGCs were positive for CD11c, CD11b, CD32, CD16, HLA-DR and MMP9, and negative for CD163, CD206 and CD64 giving a molecular profile of proinflammatory M1 but not immunosuppressive M2. MGCs were significantly related to decreased lymph node metastasis (p = 0.011), low pTNM stage (p = 0.044), favorable survival (p = 0.04), squamous cell cancer type rather than other histopathological subtypes (p = 0.020) and associated to better differentiation (p = 0.063). Conclusions: MGCs belong to M1 macrophage and perform phagocytosis and scavenging of cancer cells that would benefit patients' survival and could serve as a prognostic marker
Risk factors for cerebrovascular disease mortality among the elderly in Beijing: A competing risk analysis
Objective: To examine the associations of combined lifestyle factors and physical conditions with cerebrovascular diseases (CBVD) mortality, after accounting for competing risk events, including death from cardiovascular diseases, cancers and other diseases. Methods: Data on 2010 subjects aged over 55 years were finally analyzed using competing risk models. All the subjects were interviewed by the Beijing Longitudinal Study of Aging (BLSA), in China, between 1 January 1992 and 30 August 2009. Results: Elderly females were at a lower risk of death from CBVD than elderly males (HR = 0.639, 95% CI = 0.457-0.895). Increasing age (HR = 1.543, 95% CI = 1.013-2.349), poor self-rated health (HR = 1.652, 95% CI = 1.198-2.277), hypertension (HR = 2.201, 95% CI = 1.524-3.178) and overweight (HR = 1.473, 95% CI = 1.013-2.142) or obesity (HR = 1.711, 95% CI = 1.1754-2.490) was associated with higher CBVD mortality risk. Normal cognition function (HR = 0.650, 95% CI = 0.434-0.973) and living in urban (HR = 0.456, 95% CI = 0.286-0.727) was associated with lower CBVD mortality risk. Gray\u27s test also confirmed the cumulative incidence (CIF) of CBVD was lower in the \u27married\u27 group than those without spouse, and the mortality was lowest in the \u27nutrition sufficient\u27 group among the \u27frequent consumption of meat group\u27 and the \u27medial type group\u27 (P valu
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