Probe Footprint Estimation in Eddy-Current Imaging

Eddy-current imaging has been described in detail in previous publications [1,2,3]. As with other imaging systems, the image of an object represents blurring of the structures of the object by the system point spread function (PSF). Differing from other imaging systems, the PSF is very large and causes great spatial blurring of the object. This is because the eddy-current probe is a coil; its active area is much greater than the size of a beam of light, sound, or x-ray

Surface Coverage Issues When Using Eddy Current Arrays

Over the past few years, the need for improved flaw detection sensitivity has motivated the development of imaging techniques for eddy current testing [1]. The imaging approach has a major advantage over more traditional eddy current detection methods as image processing routines may be applied to the eddy current images to enhance flaw detection capability. Smaller probes are also being developed to further improve the resolution and sensitivity of flaw detection. The use of smaller probes, however, requires shorter data acquisition sampling intervals. This forces a tradeoff between inspection resolution and inspection speed. The need for simultaneous improvement in both inspection resolution and speed has stimulated an interest in eddy current arrays. As a result, a powerful new eddy current array inspection technology is emerging

Functional appliance therapy - the experimental and clinical perspective

Eddy current imaging has been used in eddy current nondestructive testing in order to identify small surface flaws in conducting materials [1–5]. However, the conventional pancake coil probes provide blurred flaw images because the eddy current in the test material induced by the probe spreads over a larger area than the coil size. The authors first applied popular deconvolution method to blurred ECT flaw images to get clear flaw images. However, it did not work well because a small drill hole signal does not correlate linearly to slit flaw signals. So the authors have devised a new ECT method utilizing a tangential coil and computerized tomography inversion technique in order to obtain clearer ECT flaw images

Expression of phosphorylated eukaryotic initiation factor 2 alpha in neuronal apoptosis beta-amyloid toxicity

Inhibition of protein synthesis has been demonstrated in experimental ischemia. Increasing lines of evidence show that inhibiting protein translation results in apoptosis. Translation of protein is initiated by binding of initiator Met-tRNA to the 40S ribosomal subunit, which subsequently joins the 60S ribosomal subunit by hydrolyzing the GTP into GDP. The eukaryotic initiation factor 2 alpha (eIF2a)-GDP complex is released in exchange for GTP. Phosphorylation of eIF2a blocks the exchange of GTP and shutdowns protein synthesis leading to apoptosis. Since apoptosis of neurons is considered to be the one of death pathways in Alzheimer's disease (AD), this study aims to investigate whether phosphorylation of eIF2a is the key-signaling pathway leading to neuronal apoptosis in AD. Human neuroblastoma SH-SY5Y cells treated with the calcium ionophore A23187 underwent apoptosis, as reported by other laboratories. Early after treatment of A23187, phosphorylation of eIF2a was markedly increased. Flavonoids such as genistein and quercetin suppress tumor growth by inhibiting protein synthesis. Treatment of cells with both drugs induced a marked increase in eIF2a phosphorylation. Condensation and disintegration of DNA in cells shown by nuclear staining were found after 24 h. Furthermore, cells treated with b-amyloid peptide (Ab25-35) led to phosphorylation of eIF2a, and eventually resulted in apoptosis. Taken together, the results suggest that phosphorylation of eIF2a may be a key molecular pathway leading the neuronal apoptosis. Elucidation of this pathway may reshape the therapeutic interventions against AD. Supported by Research Grant Council, Hong Kong SA

A collaborative and semantic data management framework for ubiquitous computing environment

One fundamental task to realize the envisioned ubiquitous computing paradigm is the proper management of the data generated in this environment. The special characteristics of high distribution, heterogeneity, mobility, and autonomy of the ubiquitous computing environment introduce great difficulties in data management, which cannot be easily overcome using existing solutions. We propose a collaborative and semantic data management framework that is incentive-based. The incentives encourage contribution from and foster cooperation among different devices in the environment. Devices that contribute more to the successful information accesses of other devices will gain more routing knowledge, which in turn improves the service of their own queries. We suggest using ontology-based metadata to explicitly and formally describe data semantics. Our routing scheme would redirect queries to make full use of cached data available in the environment. Experiment results show that our system can serve information accesses in the ubiquitous environment with less communication costs than other similar systems. © Springer-Verlag Berlin Heidelberg 2004.link_to_subscribed_fulltex