Bone cell–materials interaction on alumina ceramics with different grain sizes

The objective of this work was to study adhesion, proliferation and differentiation of osteoblast cells (OPC1) on alumina ceramic, a bio-inert material. Alumina ceramic with different average grain sizes, 1 μm and 12 μm, respectively, were used in as-prepared condition without any grinding and polishing to understand the influence of grain size on cell–material interactions. Scanning electron microscopy and confocal imaging were used to study attachment, adhesion and differentiation of OPC1 cells. Cells attached, proliferated and differentiated well on both the substrates. Adhesion of cells, as assessed by observing the production of vinculin, was found to be a consistent phenomenon on both the substrates. On day 5 of cell culture, significant cell-attachment was observed and vinculin was detected throughout cytoplasm. MTT assay showed that proliferation of OPC1 cells was consistently higher in the case of 12 μm-alumina. Cells of different morphology, nodular, plate-like as well as elongated, were found to get anchored at grains, grain boundaries as well as pores. On day 16, there were clear signs of mineralization as well. Over all, alumina with average grain size of 12 μm showed better cell-attachment, growth and differentiation compared to 1 μm grain size samples.     

Effect of epoxy functionalized compatibilizer on the mechanical properties of low‐density polyethylene/plasticized tapioca starch blends

A series of low‐density polyethylene (LDPE) blends with varying proportions of plasticized tapioca starch have been used for the study of their mechanical properties. A functionalized epoxy resin, namely, poly(ethylene‐co‐glycidyl methacrylate) has been used as the compatibilizer. The impact and tensile properties have been measured by standard ASTM methods. The mechanical properties are seen to improve significantly with the addition of the epoxy compatibilizer, approaching values close to those of virgin LDPE. The scanning electron micrographs of the compatibilized blends show ductile failure which evidently contribute to improved mechanical properties. © 2001 Society of Chemical Industry     

Development and long-term in vivo evaluation of a biodegradable urethane-doped polyester elastomer

We have recently reported upon the development of crosslinked urethane-doped polyester (CUPE) network elastomers, which was motivated by the desire to overcome the drawbacks presented by crosslinked network polyesters and biodegradable polyurethanes for soft tissue engineering applications. Although the effect of the isocyanate content and post-polymerization conditions on the material structure-property relationship was examined in detail, the ability of the diol component to modulate the material properties was only studied briefly. Herein, we present a detailed report on the development of CUPE polymers synthesized using diols 4, 6, 8, 10, or 12 methylene units in length in order to investigate what role the diol component plays on the resulting material's physical properties, and assess their long-term biological performance in vivo. An increase in the diol length was shown to affect the physical properties of the CUPE polymers primarily through lowered polymeric crosslinking densities and elevated material hydrophobicity. The use of longer chain diols resulted in CUPE polymers with increased molecular weights resulting in higher tensile strength and elasticity, while also increasing the material hydrophobicity to lower bulk swelling and prolong the polymer degradation rates. Although the number of methylene units largely affected the physical properties of CUPE, the choice of diol did not affect the overall polymer cell/tissue-compatibility both in vitro and in vivo. In conclusion, we have established the diol component as an important parameter in controlling the structure-property relationship of the polymer in addition to diisocyanate concentration and post-polymerization conditions. Expanding the family of CUPE polymers increases the choices of biodegradable elastomers for tissue engineering applications.     

Enhancing effective depth-of-field by image fusion using mathematical morphology

Reduced depth-of-field (DOF) poses a problem in the light optical imaging system, since the objects present outside this zone appear blurry in the recorded image. The effective DOF of the sensor may be enhanced considerably without compromising the quality of the image by fusing images captured with different focused regions. This paper presents an image fusion technique suitable for combining multifocus images of a scene. The method employs morphological filters to select sharply focused regions from various images and then combines them together to reconstruct the image in which all the regions are properly focused. A performance measure based on image gradients is used to compare the results obtained by the proposed method with those obtained by other image fusion techniques.     

Oligoclonal protein bands and Ig isotype switching in multiple myeloma treated with high-dose therapy and hematopoietic cell transplantation

Multiple myeloma (MM) is usually characterized by production of a single serum monoclonal protein of constant isotype and light-chain restriction. Multiple Ig isotypes and isotype switches, which are rare in untreated patients, are reported to be more common in patients undergoing myeloablative therapy. These additional protein bands, detected by immunofixation electrophoresis (IFE), could be due to altered paraprotein production by the malignant plasma cell clone or oligoclonal Ig production during recovery of B-cell function after myeloablative therapy. We analyzed abnormal protein bands (APB), distinct from the presenting paraprotein, in 550 patients receiving high-dose therapy with autologous hematopoietic cell transplantation at a single institution. Fifty-five patients (10%) had APB, 48 had oligoclonal bands (OB), and 23 had an apparent isotype switch (IS) on IFE (16 had both OB and IS). Morphologic and flow cytometric examination of bone marrow in 17 patients with IS showed no evidence of a clonal plasma cell isotype switch. Patients with APB had significantly higher complete response to therapy (67% v 37%, P = .001). To assess the independent prognostic relevance of APB, a multivariate analysis was performed among 471 patients surviving at least 12 months from first transplant (all patients developing APB had done so by 12 months from first transplant). APB (in 50 patients) was a favorable feature for both event-free (rank 3, P = .004) and overall survival (rank 3, P = .0005). We propose that OB and IS are likely to be due to recovery of Ig production rather than alterations in the biology of the malignant plasma cell clone.     

Automatic clustering algorithm based on multi-objective Immunized PSO to classify actions of 3D human models

Multi-objective clustering algorithms are preferred over its conventional single objective counterparts as they incorporate additional knowledge on properties of data in the from of objectives to extract the underlying clusters present in many datasets. Researchers have recently proposed some standardized multi-objective evolutionary clustering algorithms based on genetic operations, particle swarm optimization, clonal selection principles, differential evolution and simulated annealing, etc. In many cases it is observed that hybrid evolutionary algorithms provide improved performance compared to that of individual algorithm. In this paper an automatic clustering algorithm MOIMPSO (Multi-objective Immunized Particle Swarm Optimization) is proposed, which is based on a recently developed hybrid evolutionary algorithm Immunized PSO. The proposed algorithm provides suitable Pareto optimal archive for unsupervised problems by automatically evolving the cluster centers and simultaneously optimizing two objective functions. In addition the algorithm provides a single best solution from the Pareto optimal archive which mostly satisfy the users' requirement. Rigorous simulation studies on 11 benchmark datasets demonstrate the superior performance of the proposed algorithm compared to that of the standardized automatic clustering algorithms such as MOCK, MOPSO and MOCLONAL. An interesting application of the proposed algorithm has also been demonstrated to classify the normal and aggressive actions of 3D human models.     

Study on Alloying Behaviour of Uranium Zirconium Alloy

Uranium–zirconium alloy is the potential candidate material as metallic fuels for nuclear reactor applications. Fabrication of uranium zirconium alloy can be made either by powder metallurgy or by melting method. Both the method has its own advantages and selection of the fabrication route depends on its application as fuel. In this work investigations were carried out on fabrication of uranium–zirconium alloys (i.e. U–40 wt% Zr, U–50 wt% Zr, U–60 wt% Zr and U–70 wt% Zr) using both powder metallurgy and melting method. It is heat treated at different conditions. Apart from other characterization, X-ray diffraction analysis was carried out to evaluate phase content of the alloy and reported here.     

Design and implementation of a realtime co-processor for denoising Fiber Optic Gyroscope signal

The amount of noise present in the Fiber Optic Gyroscope (FOG) signal limits its applications and has a negative impact on navigation system. Existing algorithms such as Discrete Wavelet Transform (DWT), Kalman Filter (KF) denoise the FOG signal under static environment, however denoising fails in dynamic environment. Therefore in this paper an Adaptive Moving Average Dual Mode Kalman Filter (AMADMKF) is developed for denoising the FOG signal under both the static and dynamic environments. Performance of the proposed algorithm is compared with DWT and KF techniques. Further, a hardware Intellectual Property (IP) of the algorithm is developed for System on Chip (SoC) implementation using Xilinx Virtex-5 Field Programmable Gate Array (Virtex-5FX70T-1136). The developed IP is interfaced as a Co-processor/ Auxiliary Processing Unit (APU) with the PowerPC (PPC440) embedded processor of the FPGA. It is proved that the proposed system is an efficient solution for denoising the FOG signal in real-time environment. Hardware acceleration of developed Co-processor is 65× with respect to its equivalent software implementation of AMADMKF algorithm in the PPC440 embedded processor.     

GENERAL LINEAR PROCESSES:A PROPERTY OF THE EMPIRICAL PROCESS APPLIED TO DENSITY AND MODE ESTIMATION

Abstract. General linear processes do not usually satisfy strong mixing conditions. Therefore, we investigate the empirical process based on samples from such a general linear process by using a truncation argument and derive a local fluctuation inequality. It is well known that such a fluctuation inequality is of basic importance in the study of the empirical process. Here it is applied to obtain a rate of almost sure (a.s.) convergence for certain density estimators in the supremum norm. This extends a local result obtained by Chanda. As a direct corollary a rate of a.s. convergence for a mode estimator is obtained.