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61.
The effects of different concentrations of various polysorbates on the release rate of atenolol from film-coated tablets were evaluated. The release profile of atenolol showed that increasing the concentration of polysorbate resulted in an increase in the release rate of atenolol. The type of polysorbate had less effect on the release rate of atenolol. This study revealed that the release kinetic of atenolol from these film-coated tablets was a function of polysorbate concentration. Correlation coefficients of kinetic models could not solely determine the suitability of the models; the sum of the least square of differences also should be calculated when different kinetic models have similar correlation coefficients.  相似文献   
62.
Fibroblast growth factor receptor (FGFR) activation leads to receptor autophosphorylation and increased tyrosine phosphorylation of several intra cellular proteins. We have previously shown that autophosphorylated tyrosine 766 in FGFR1 serves as a binding site for one of the SH2 domains of phospholipase Cy and couples FGFR1 to phosphatidylinositol hydrolysis in several cell types. In this report, we describe the identification of six additional autophosphorylation sites (Y-463, Y-583, Y-585, Y-653, Y-654 and Y-730) on FGFR1. We demonstrate that autophosphorylation on tyrosines 653 and 654 is important for activation of tyrosine kinase activity of FGFR1 and is therefore essential for FGFR1-mediated biological responses. In contrast, autophosphorylation of the remaining four tyrosines is dispensable for FGFR1-mediated mitogen-activated protein kinase activation and mitogenic signaling in L-6 cells as well as neuronal differentiation of PC12 cells. Interestingly, both the wild-type and a mutant FGFR1 (FGFR1-4F) are able to phosphorylate Shc and an unidentified Grb2-associated phosphoprotein of 90 kDa (pp90). Binding of the Grb2/Sos complex to phosphorylated Shc and pp90 may therefore be the key link between FGFR1 and the Ras signaling pathway, mito-genesis, and neuronal differentiation.  相似文献   
63.
This paper presents a polymer-based wafer-level integration technology suitable for integrating RF and mixed-signal circuits and systems. In this technology, disparate dies can be integrated together using a batch fabrication process. Very high density die-to-die interconnects with widths currently as small as 25 mum are implemented. To demonstrate the capabilities of this technology, a 10-GHz receiver front-end implemented in 0.18-mum CMOS technology is integrated with a high-resistivity Si substrate and embedded passives. By adjusting the input matching of the receiver using the embedded passives fabricated on the high-resistivity Si substrate, the input matching and conversion gain of the front-end receiver are improved  相似文献   
64.
Equilibrium on line method (ELM) for imposition of Neumann boundary conditions in the finite point method (FPM) is presented. In contrary to weak‐form‐based methods, strong‐form‐based methods such as the FPM are often unstable and less accurate, especially for problems governed by partial differential equations with Neumann (derivative) boundary conditions. In this paper, a truly meshless approach for imposition of Neumann boundary conditions in the FPM is proposed and adopted for 2D elasticity analyses. In the proposed method, equilibrium on lines on the Neumann boundary conditions is satisfied as Neumann boundary condition equations. Numerical studies show that this method for imposition of Neumann boundary is simple to implement and computationally efficient and also leads to more stable and accurate results. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
65.
New enrichment functions are proposed for crack modelling in orthotropic media using the extended finite element method (XFEM). In this method, Heaviside and near‐tip functions are utilized in the framework of the partition of unity method for modelling discontinuities in the classical finite element method. In this procedure, by using meshless based ideas, elements containing a crack are not required to conform to crack edges. Therefore, mesh generation is directly performed ignoring the existence of any crack while the method remains capable of extending the crack without any remeshing requirement. Furthermore, the type of elements around the crack‐tip remains the same as other parts of the finite element model and the number of nodes and consequently degrees of freedom are reduced considerably in comparison to the classical finite element method. Mixed‐mode stress intensity factors (SIFs) are evaluated to determine the fracture properties of domain and to compare the proposed approach with other available methods. In this paper, the interaction integral (M‐integral) is adopted, which is considered as one of the most accurate numerical methods for calculating stress intensity factors. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
66.
One of the most important needs in the post‐genome era is providing the researchers with reliable and efficient computational tools to extract and analyse this huge amount of biological data, in which DNA copy number variation (CNV) is a vitally important one. Array‐based comparative genomic hybridisation (aCGH) is a common approach in order to detect CNVs. Most of methods for this purpose were proposed for one‐dimensional profiles. However, slightly this focus has moved from one‐ to multi‐dimensional signals. In addition, since contamination of these profiles with noise is always an issue, it is highly important to have a robust method for analysing multi‐sample aCGH profiles. In this study, the authors propose robust group fused lasso which utilises the robust group total variations. Instead of l 2,1 norm, the l 1l 2 M‐estimator is used which is more robust in dealing with non‐Gaussian noise and high corruption. More importantly, Correntropy (Welsch M‐estimator) is also applied for fitting error. Extensive experiments indicate that the proposed method outperforms the state‐of‐the art algorithms and techniques under a wide range of scenarios with diverse noises.Inspec keywords: genomics, DNA, molecular biophysics, Gaussian noise, entropyOther keywords: robust group fused lasso, multisample copy number variation detection, post‐genome era, computational tools, biological data, DNA copy number variation, array‐based comparative genomic hybridisation, one‐dimensional profiles, one‐dimensional signals, multidimensional signals, profile contamination, multisample aCGH profiles, robust group total variations, l1 ‐l2 M‐estimator, nonGaussian noise, correntropy, Welsch M‐estimator, fitting error, diverse noises  相似文献   
67.
This article deals with the study of low velocity impact response on sandwich plates with functionally graded face sheets. High-order sandwich plate theory is improved by considering the in-plane stresses of the core that usually are ignored in the analysis of sandwich structures. A new approach is used to reduce the equations of motion from 27 equations to 15 equations and then solving them for both unsymmetric and symmetric sandwich plates. The model is also checked by finite element simulation and by comparing with other references for validation. A parametric study is done for various geometrical and mechanical properties.  相似文献   
68.
69.
BACKGROUND & AIMS: Previous findings suggest that TH1 cellular immune responses contribute to Helicobacter-associated gastritis. To further investigate this issue, interleukin 4 gene targeted mice were infected with Helicobacter felis, and a series of adoptive transfer experiments was performed to evaluate the role of both TH1 and TH2 cells. METHODS: Antigen-specific spleen cells from immunized/challenged or nonimmunized/infected mice or CD4+ T-cell lines were transferred adoptively into naive recipients before live bacterial challenge. RESULTS: Transfer of cells from both groups of donors as well as TH1 or TH2 cell lines exacerbated gastric inflammation in the recipients. No effect on bacterial load was observed in recipients of bulk spleen cells from infected mice or recipients of TH1 cell lines. In contrast, when either a TH2 cell line or bulk cells from immunized challenged mice were transferred adoptively, recipients showed a dramatic reduction in bacterial load. Increased numbers of bacteria were also noted in interleukin 4-deficient mice. CONCLUSIONS: These data suggest a differential contribution of TH1 and TH2 cell-mediated immune responses in Helicobacter infection: one associated with the pathogenesis of disease (TH1 phenotype) and the other associated with protection from or control of infection (TH2 phenotype).  相似文献   
70.
Continuous nanoporous mordenite membranes were reproducibly fabricated on tubular microporous mullite supports. The ceramic supports were prepared during calcination of kaolin clay, followed by a leaching post-treatment. A template-free seeded hydrothermal synthesis in a brass autoclave was used to prepare the zeolite membranes. The membranes and the powder crystals collected from the bottom of the autoclave were characterized with XRD, SEM and EDAX. PV properties of the membranes were assessed using dehydration of different ethanol–water mixtures. XRD patterns showed that mordenite was the only zeolitic material present in the membrane. SEM examination of the membrane revealed that thickness of the mordenite crystals filling the voids as a dense thin-layer among the mullite support was 5–10 μm. The continuous top-layer of the membrane was formed by many large and oriented crystals. EDAX analysis showed a Si to Al ratio of 6 for the mordenite powder. The polycrystalline membranes were found to be selective for dehydration of different ethanol/water mixtures. It was concluded that selective adsorption of water on the zeolite pores, small intercrystalline defects and a pinhole-free structure of the membrane layer leaded to high water selectivity of the mordenite membranes studied.  相似文献   
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