1,204 research outputs found
Detection of eight different tospovirus species by a monoclonal antibody against the common epitope of NSs protein
Rabbit antisera against the nucleocapsid protein (NP) have been commonly used for detection of tospoviruses and classification into serogroups or serotypes. Mouse monoclonal antibodies (MAbs) with high specificity to the NPs have also been widely used to identify tospovirus species. Recently, a serogroup-specific MAb against the NSs protein of Watermelon silver mottle virus (WSMoV) was produced by our laboratory to react with five members of WSMoV serogroup, i.e., WSMoV, Capsicum chlorosis virus (CaCV), Calla lily chlorotic spot virus (CCSV), Peanut bud necrosis virus (PBNV) and Watermelon bud necrosis virus (WBNV). The epitope recognized by the NSs MAb was determined and the comparison with the reported sequences of tospoviral NSs proteins revealed that the epitope is highly conserved at the N-terminal region of NSs proteins among members of WSMoV and Iris yellow spot virus (IYSV) serogroups, and Melon yellow spot virus (MYSV) serotype. When the NSs MAb was further used to react with the crude antigens of MYSV serotype, IYSV and Tomato yellow ring virus (TYRV) of IYSV serogroup, strong serological reactions, both in ELISA and western blotting, were observed. Thus, our results indicated that the NSs MAb is a useful and convenient tool for detection of the eight tospovirus species. It is also suggested that these eight Asian-type tospoviruses, i.e., WSMoV, CaCV, CCSV, PBNV, WBNV, MYSV, IYSV and TYRV, may share a common evolutionary ancesto
Afforestation for reduction of NOx concentration in Lanzhou China
Environment International, 34 (5), 688-697The article of record as published may be found at http://dx.doi.org/10.1016/j.envint.2007.12.01
Involvement of lipid rafts in adhesion-induced activation of Met and EGFR
<p>Abstract</p> <p>Background</p> <p>Cell adhesion has been shown to induce activation of certain growth factor receptors in a ligand-independent manner. However, the mechanism for such activation remains obscure.</p> <p>Methods</p> <p>Human epidermal carcinoma A431 cells were used as a model to examine the mechanism for adhesion-induced activation of hepatocyte growth factor receptor Met and epidermal growth factor receptor (EGFR). The cells were suspended and replated on culture dishes under various conditions. The phosphorylation of Met at Y1234/1235 and EGFR at Y1173 were used as indicators for their activation. The distribution of the receptors and lipid rafts on the plasma membrane were visualized by confocal fluorescent microscopy and total internal reflection microscopy.</p> <p>Results</p> <p>We demonstrate that Met and EGFR are constitutively activated in A431 cells, which confers proliferative and invasive potentials to the cells. The ligand-independent activation of Met and EGFR in A431 cells relies on cell adhesion to a substratum, but is independent of cell spreading, extracellular matrix proteins, and substratum stiffness. This adhesion-induced activation of Met and EGFR cannot be attributed to Src activation, production of reactive oxygen species, and the integrity of the cytoskeleton. In addition, we demonstrate that Met and EGFR are independently activated upon cell adhesion. However, partial depletion of Met and EGFR prevents their activation upon cell adhesion, suggesting that overexpression of the receptors is a prerequisite for their self-activation upon cell adhesion. Although Met and EGFR are largely distributed in 0.04% Triton-insoluble fractions (<it>i.e</it>. raft fraction), their activated forms are detected mainly in 0.04% Triton-soluble fractions (<it>i.e</it>. non-raft fraction). Upon cell adhesion, lipid rafts are accumulated at the cell surface close to the cell-substratum interface, while Met and EGFR are mostly excluded from the membrane enriched by lipid rafts.</p> <p>Conclusions</p> <p>Our results suggest for the first time that cell adhesion to a substratum may induce a polarized distribution of lipid rafts to the cell-substratum interface, which may allow Met and EGFR to be released from lipid rafts, thus leading to their activation in a ligand-independent manner.</p
Digital image correlation approach to cracking and decohesion in a brittle coating/ductile substrate system
By using a digital image correlation technique, the full/local field strain in a brittle coating/ductile substrate system during tension has been successfully monitored. One of the most important experimental results indicates that the distribution of interfacial shear stress in the segmented coating is antisymmetric about the center, which clarifies several controversial assumptions introduced in theoretical models. Two key mechanical properties of thermal barrier coatings, fracture strength in coating and interfacial adhesion strength, were determined as 35.0 ± 4.6 and 14.1 ± 3.2 MPa, respectively, which are consistent with available experimental data
Effects of substrate curvature radius, deposition temperature and coating thickness on the residual stress field of cylindrical thermal barrier coatings
In a thermal barrier coating (TBC) system with cylindrical geometry, the position of coating plays an important role in the distribution of residual stress. In this paper, the residual stress field in three different types of TBCs with cylindrical geometry has been analyzed. The main focus is on the effects of substrate curvature radius, deposition temperature and coating thickness on the residual stress distribution during a deposition process. The results show that the substrate curvature radius significantly affects the distributions of radial and hoop residual stresses, which are in good agreement with experimental measurements by photo-stimulated luminescence piezospectroscopy (Wang et al., Acta Mater., 2009, 57(1):182â195). The maximum radial residual stress locates closely to the coating/thermal grown oxide interface. However, the maximum hoop residual stress lies in the thermal grown oxide layer, which is much more than other three layers and presents a strong stress singularity along the thickness direction
Process intensification of BaSO4 nanoparticle preparation with agitation of microbubbles
AbstractThis study presents a novel technique for the controllable preparation of BaSO4 nanoparticles via the introduction of microbubbles into the reaction system. A high-concentration system based on barite industry was used, with saturated aqueous Na2SO4 and BaS solutions as the reactants. Microbubbles were generated by a membrane dispersion microreactor. The mixing performance was characterized using parallel competing reactions. The effects of various operation parameters on the nanoparticles were determined, and the reaction conditions were optimized. The results showed that the mixing performance could be improved by introducing microbubbles. The BaSO4 nanoparticles were controllably prepared, with a relatively narrow size distribution. The average particle size could likewise be reduced to approximately 40nm. A dimensionless micromixing scale of the microbubble flow was defined, and a model for predicting the BaSO4 particle size was proposed. The calculated results were consistent with the experimental data
Adaptive Finite Element Methods with Inexact Solvers for the Nonlinear Poisson-Boltzmann Equation
In this article we study adaptive finite element methods (AFEM) with inexact
solvers for a class of semilinear elliptic interface problems. We are
particularly interested in nonlinear problems with discontinuous diffusion
coefficients, such as the nonlinear Poisson-Boltzmann equation and its
regularizations. The algorithm we study consists of the standard
SOLVE-ESTIMATE-MARK-REFINE procedure common to many adaptive finite element
algorithms, but where the SOLVE step involves only a full solve on the coarsest
level, and the remaining levels involve only single Newton updates to the
previous approximate solution. We summarize a recently developed AFEM
convergence theory for inexact solvers, and present a sequence of numerical
experiments that give evidence that the theory does in fact predict the
contraction properties of AFEM with inexact solvers. The various routines used
are all designed to maintain a linear-time computational complexity.Comment: Submitted to DD20 Proceeding
OpenMP on Networks of Workstations
We describe an implementation of a sizable subset of OpenMP on networks of workstations (NOWs). By extending the availability of OpenMP to NOWs, we overcome one of its primary drawbacks compared to MPI, namely lack of portability to environments other than hardware shared memory machines. In order to support OpenMP execution on NOWs, our compiler targets a software distributed shared memory system (DSM) which provides multi-threaded execution and memory consistency. This paper presents two contributions. First, we identify two aspects of the current OpenMP standard that make an implementation on NOWs hard, and suggest simple modifications to the standard that remedy the situation. These problems reflect differences in memory architecture between software and hardware shared memory and the high cost of synchronization on NOWs. Second, we present performance results of a prototype implementation of an OpenMP subset on a NOW, and compare them with hand-coded software DSM and MPI results for the same applications on the same platform. We use five applications (ASCI Sweep3d, NAS 3D- FFT, SPLASH-2 Water, QSORT, and TSP) exhibiting various styles of parallelization, including pipelined execution, data parallelism, coarse-grained parallelism, and task queues. The measurements show little difference between OpenMP and hand-coded software DSM, but both are still lagging behind MPI. Further work will concentrate on compiler optimization to reduce these differences
A modified layer-removal method for residual stress measurement in electrodeposited nickel films
Combining the traditional layer-removal method with a cantilever beam model, a modified layer-removal method is developed and used to measure residual stress in single and multi-layer electrodeposited nickel films with thickness of 2.5 ÎŒm. The out-of-plane displacement of the free tip of a cantilever beam is measured by the digital speckle correlation method. The results show that residual stress in a single semimat nickel film is compressive, while in a multi-layer system composed of dark, semimat and holophote nickel, residual stress in the surface layer is tensile. Residual stress decreases gradually with the increase of etching depths of single and multi-layer films. These findings are in qualitative agreement with nanoindentation tests, which confirms the reliability of the modified layer-removal method
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