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Number of results: 46
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Abstract

Tight junction proteins are important for the maintenance and repair of the intestinal mucosal barrier. The present study investigated relationships among tight junction protein gene expres- sion, porcine epidemic diarrhea virus (PEDV) infection, and intestinal mucosal morphology in piglets. We compared the expression of six tight junction proteins (ZO-1, ZO-2, Occludin, Claudin-1, Claudin-4, and Claudin-5) between seven-day-old piglets infected with PEDV and normal piglets, as well as in PEDV-infected porcine intestinal epithelial cells (IPEC-J2). We also evaluated differences in mucosal morphology between PEDV-infected and normal piglets. The expression of six tight junction protein genes was lower in PEDV-infected piglets than in the normal animals. The expression of ZO-1, ZO-2, Occludin, and Claudin-4 in the intestine tissue was significantly lower (p<0.05) in PEDV-infected than in normal piglets. The expression of Claudin-5 in the jejunum was significantly lower in PEDV-infected piglets than in the normal animals (p<0.01). The expression of Claudin-1 and Claudin-5 genes in the ileum was signifi- cantly higher in PEDV-infected piglets than in normal piglets (p<0.01). Morphologically, the intestinal mucosa in PEDV-infected piglets exhibited clear pathological changes, including breakage and shedding of intestinal villi. In PEDV-infected IPEC-J2 cells, the mRNA expression of the six tight junction proteins showed a downward trend; in particular, the expression of the Occludin and Claudin-4 genes was significantly lower (p<0.01). These data suggest that the expression of these six tight junction proteins, especially Occludin and Claudin-4, plays an important role in maintaining the integrity of the intestinal mucosal barrier and resistance to PEDV infection in piglets.
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Abstract

Function of duck (Anas platyrhynchos) major histocompatibility complex class I (Anpl-MHC I) molecules in binding peptides is through the peptide binding groove (PBG), which is thought to be influenced by the high polymorphism of α1 and α2 domains. However, little is known about the polymorphism of Anpl-MHC I peptide binding domain (PBD), especially in the domestic duck. Here, we analyzed the polymorphism of forty-eight Anpl-MHC I α1 and α2 domains from domestic duck breeds previously reported. All sequences were analyzed through multiple sequence alignment and a phylogenetic tree was constructed. The coefficient of variance of the peptide binding domains (PBDs) from WS, CV, JD, and SX duck breeds was estimated based on the Wu-Kabat variability index, followed by the location of the highly variable sites (HVSs) on reported crystal structure models. Analysis of α1 and α2 domains showed common features of classical MHC class I and high polymorphism, especially in α1 domain. The constructed phylogenetic tree showed that PBDs of domestic ducks did not segregate based on breeds and had a close phylogenetic relationship, even with wild ducks. In each breed, HVSs were mostly located in the PBG, suggesting that they might determine peptide-binding characteristics and subsequently influence peptide presentation and recognition. The combined results of sequence data and crystal structure provide novel valuable insights into the polymorphism and diversity of Anpl-MHC I PBDs that will facilitate further studies on disease resistance differences between duck breeds and the development of cytotoxic T-lymphocyte (CTL) epitope vaccines suited for preventing diseases in domestic ducks.
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Abstract

The central theme of this work was to analyze high aspect ratio structure having structural nonlinearity in low subsonic flow and to model nonlinear stiffness by finite element-modal approach. Total stiffness of high aspect ratio wing can be decomposed to linear and nonlinear stiffnesses. Linear stiffness is modeled by its eigenvalues and eigenvectors, while nonlinear stiffness is calculated by the method of combined Finite Element-Modal approach. The nonlinear modal stiffness is calculated by defining nonlinear static load cases first. The nonlinear stiffness in the present work is modeled in two ways, i.e., based on bending modes only and based on bending and torsion modes both. Doublet lattice method (DLM) is used for dynamic analysis which accounts for the dependency of aerodynamic forces and moments on the frequency content of dynamic motion. Minimum state rational fraction approximation (RFA) of the aerodynamic influence coefficient (AIC) matrix is used to formulate full aeroelastic state-space time domain equation. Time domain dynamics analyses show that structure behavior becomes exponentially growing at speed above the flutter speed when linear stiffness is considered, however, Limit Cycle Oscillations (LCO) is observed when linear stiffness along with nonlinear stiffness, modeled by FE-Modal approach is considered. The amplitude of LCO increases with the increase in the speed. This method is based on cantilevered configuration. Nonlinear static tests are generated while wing root chord is fixed in all degrees of freedom and it needs modification if one requires considering full aircraft. It uses dedicated commercial finite element package in conjunction with commercial aeroelastic package making the method very attractive for quick nonlinear aeroelastic analysis. It is the extension of M.Y. Harmin and J.E. Cooper method in which they used the same equations of motion and modeled geometrical nonlinearity in bending modes only. In the current work, geometrical nonlinearities in bending and in torsion modes have been considered.
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Abstract

To reduce the influence of the static unbalance on an infrared missile guidance system, a new static unbalance measure system for the gimbals axes has been developed. Considering the coupling effects caused by a mass eccentricity, the static balance condition and measure sequence for each gimbal axis are obtained. A novel static unbalance test approach is proposed after analyzing the dynamic model of the measured gimbal axis. This approach is to drive the measured gimbal axis to do sinusoidal reciprocating motion in a small angle and collect its drive currents in real time. Then the static unbalance of the measured gimbal axis can be obtained by the current multi-cycle integration. Also a measuring system using the proposed approach has been developed. A balanced simulator is used to verify the proposed approach by the load and repeatability tests. The results show the proposed approach enhances the efficiency of the static unbalance measurement, and the developed measuring system is able to achieve a high precision with a greater stability.
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Abstract

A complete parametric approach is proposed for the design of the Luenberger type function Kx observers for descriptor linear systems. Based on a complete parametric solution to a class of generalized Sylvester matrix equations, parametric expressions for all the coefficient matrices of the observer are derived. The approach provides all the degrees of design freedom, which can be utilized to achieve some additional design requirements. An illustrative example shows the effect of the proposed approach.
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Abstract

We report on the photoresponse of mid-wavelength infrared radiation (MWIR) type-II superlattices (T2SLs) InAs/InAsSb high operating temperature (HOT) photoresistor grown on GaAs substrate. The device consists of a 200 periods of active layer grown on GaSb buffer layer. The photoresistor reached a 50% cut-off wavelength of 5 µm and 6 µm at 200 K and 300 K respectively. The time constant of 30 ns is observed at 200 K under 1 V bias. This is the first observation of the photoresponse in MWIR T2SLs InAs/InAsSb above 200 K.
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Abstract

Heterogeneous nuclear ribonucleoprotein K (hnRNP K), is a multifunctional protein that participates in a variety of regulatory processes of signal transduction and gene expression. To further characterize the significance of hnRNP K in different male germ cells, we investigated the expression profiles of hnRNP K at different developmental stages in pig and rat testes, and conducted a comparative analysis of expression patterns between these two species. In porcine testis development, both the mRNA and protein level of hnRNP K were down-regulated from 3 months to 8 months. However, the expression level of hnRNP K was abundant across the embryonic period in rats, and decreased gradually from 0 day post partum (dpp) to 14 dpp, then increased with the highest level presenting at 90 dpp. Immunolocalization analysis further confirmed the differential expression and localization of hnRNP K protein during testis development in pigs and rats. The results showed that hnRNP K was widely distributed in gonocytes, spermatogonia, sertoli cells and Leydig cells. The dynamic expression profile of hnRNP K may imply its crucial and potential roles in the development of the testis, which will provide a theoretical basis for the future study of molecular mechanism regulation of spermatogenesis.
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Abstract

The aim was to explore the feasibility of using bamboo vinegar powder as an antibiotics substitute in weaning piglets. Forty-five healthy Duroc × Landrance × Yorshire piglets (weight 6.74 ± 0.17 kg; age 31 days) were randomly divided into the control group (basic diet), ANT group (basic diet + 0.12% compound antibiotics), BV1 group (basic diet + 0.1% bamboo vinegar powder), BV5 group (basic diet + 0.5% bamboo vinegar powder) and BV10 group (basic diet + 1% bamboo vinegar powder). MyD88 and CD14 expression in immune tissues was examined using real-time PCR. MyD88 expression in the control group were significantly lower than that in other groups in all tissues (p<0.05), while CD14 expression showed the opposite trend. MyD88 expression was significantly higher in the BV10 group than in other groups in lung tissue (P<0.05), significantly higher in the ANT group than in the BV1 group in the kidneys (P<0.05), significantly higher in the BV10 group than in the BV1 group in the thymus (P<0.05), and signifi- cantly higher in the BV1 group than in the BV10 group in the lymphatic tissue (P<0.05). These differences between experimental groups were not observed for the CD14 gene (P>0.05). Thus, adding bamboo vinegar powder to the basic diet of weaning piglets had immune effects similar to antibiotics and the effect was dose-dependent. Moreover, the MyD88 and CD14 genes appear to play a role in these immune effects
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Abstract

Sapelovirus A (SV-A) is a positive-sense single-stranded RNA virus which is associated with acute diarrhea, pneumonia and reproductive disorders. The virus capsid is composed of four proteins, and the functions of the structural proteins are unclear. In this study, we expressed SV-A structural protein VP1 and studied its antigenicity and immunogenicity. SDS-PAGE analysis revealed that the target gene was expressed at high levels at 0.6 mM concentration of IPTG for 24 h. The mouse polyclonal antibody against SV-A VP1 protein was produced and reached a high antiserum titer (1: 2,048,000). Immunized mice sera with the recombinant SV-A VP1 protein showed specific recognition of purified VP1 protein by western blot assay and could recognize native SV-A VP1 protein in PK-15 cells infected with SV-A by indirect immunofluorescence assay. The successfully purified recombinant protein was able to preserve its antigenic determinants and the generated mouse anti-SV-A VP1 antibodies could recognize native SV-A, which may have the potential to be used to detect SV-A infection in pigs.
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Abstract

The key to fingerprint positioning algorithm is establishing effective fingerprint information database based on different reference nodes of received signal strength indicator (RSSI). Traditional method is to set the location area calibration multiple information sampling points, and collection of a large number sample data what is very time consuming. With Zigbee sensor networks as platform, considering the influence of positioning signal interference, we proposed an improved algorithm of getting virtual database based on polynomial interpolation, while the pre-estimated result was disposed by particle filter. Experimental result shows that this method can generate a quick, simple fine-grained localization information database, and improve the positioning accuracy at the same time.
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Abstract

In this paper, a new lifting wavelet domain audio watermarking algorithm based on the statistical characteristics of sub-band coefficients is proposed. First of all, an original audio signal was segmented and each segment was divided into two sections. Then, the Barker code was used for synchronization, the LWT (lifting wavelet transform) was performed on each section, a synchronization code and a watermark were embedded into the first section and the second section, respectively, by modifying the statistical average value of the sub-band coefficients. The embed strength was determined adaptively according to the auditory masking property. Experiments show that the embedded watermark has better robustness against common signal processing attacks than present algorithms based on LWT and can resist random cropping in particular.
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Abstract

The main work of this paper focuses on the simulation of binary alloy solidification using the phase field model and adaptive octree grids. Ni-Cu binary alloy is used as an example in this paper to do research on the numerical simulation of isothermal solidification of binary alloy. Firstly, the WBM model, numerical issues and adaptive octree grids have been explained. Secondary, the numerical simulation results of three dimensional morphology of the equiaxed grain and concentration variations are given, taking the efficiency advantage of the adaptive octree grids. The microsegregation of binary alloy has been analysed emphatically. Then, numerical simulation results of the influence of thermo-physical parameters on the growth of the equiaxed grain are also given. At last, a simulation experiment of large scale and long-time has been carried out. It is found that increases of initial temperature and initial concentration will make grain grow along certain directions and adaptive octree grids can effectively be used in simulations of microstructure.
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Abstract

In order to enhance the acoustical performance of a traditional straight-path automobile muffler, a multi-chamber muffler having reverse paths is presented. Here, the muffler is composed of two internally parallel/extended tubes and one internally extended outlet. In addition, to prevent noise transmission from the muffler’s casing, the muffler’s shell is also lined with sound absorbing material. Because the geometry of an automotive muffler is complicated, using an analytic method to predict a muffler’s acoustical performance is difficult; therefore, COMSOL, a finite element analysis software, is adopted to estimate the automotive muffler’s sound transmission loss. However, optimizing the shape of a complicated muffler using an optimizer linked to the Finite Element Method (FEM) is time-consuming. Therefore, in order to facilitate the muffler’s optimization, a simplified mathematical model used as an objective function (or fitness function) during the optimization process is presented. Here, the objective function can be established by using Artificial Neural Networks (ANNs) in conjunction with the muffler’s design parameters and related TLs (simulated by FEM). With this, the muffler’s optimization can proceed by linking the objective function to an optimizer, a Genetic Algorithm (GA). Consequently, the discharged muffler which is optimally shaped will improve the automotive exhaust noise.
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