1,722,191 research outputs found
Endoscopic mucosal resection and endoscopic submucosal dissection as treatments for early gastrointestinal cancers in Western countries
Full text linkEarly gastrointestinal cancers are defined as lesions limited to the mucosa or submucosa without invading the muscularis propria, regardless of the presence of lymph node metastases. Although the natural history of these diseases is basically alike worldwide, its management is quite different between the East and West; aggressive surgery is frequently adopted by Western surgeons, while less invasive techniques are adopted by Asian colleagues. These techniques include endoscopic mucosal resection and endoscopic submucosal dissection which are now accepted as treatments for early gastrointestinal cancers in selected cases. Recent advances in endoscopic detection and treatment techniques, especially in Japan and Korea, have prompted Western endoscopists to learn these techniques. This review addresses recent advances regarding endoscopic resections of early gastrointestinal cancers, which promoted its use in Western countries. In addition, prospective studies on endoscopic resection in Western countries are also described
Prediction of long-term pore pressure dissipation behavior by short-term piezocone dissipation test
No full textThe coefficient of consolidation determined from piezocone dissipation test and common interpretation methods makes the predicted dissipation curve match only at 50% degree of dissipation of the measured dissipation curve. It makes it difficult to predict the long-term pore pressure dissipation behavior of in-situ soft deposits. Therefore, based on the authors' previous result [Kim YS, Lee SR, Kim YT. Application of an optimization design technique for determining the coefficient of consolidation by using piezocone test data. Computers and Geotechnics 1997;21(4): 77-93] in which an optimized coefficient of consolidation reflects well the measured dissipation trend over the input degree of dissipation range, a systematic way of predicting a more realistic pore pressure dissipation behavior at high degree of dissipation with the optimized coefficient of consolidation is proposed. It was found that, relatively over the wide range of dissipation, the optimized coefficient of consolidation is more consistent than those determined by other researchers' methods. Applied to some real examples, it is also shown that the dissipation behavior of pore water pressure at a high degree of the dissipation range can be predicted well if the coefficient of consolidation is determined using the optimization technique with the data up to around 50% dissipation. Thus, it is expected that the proposed method saves time and expenses in conducting dissipation tests in the held. (C) 2000 Published by Elsevier Science Ltd. All rights reserved
Migration technique for rotor synthetic aperture radar
No full textA new migration technique fbr ROSAR (rotor synthetic aperture radar) is presented. The system model and the Inversion algorithm are developed. To demonstrate the validity of the proposed technique, a simulation with sis point targets was performed. PI ground-based ROSAR using a network analyser was implemented for the experimental verification.X112sciescopu
Classified pixel-based windowing algorithm for polarimetric SAR speckle filtering
No full textTwo main purposes of synthetic aperture radar (SAR) speckle filtering are the preservation of the edge sharpness and the suppression of the speckle noise. However, most of the existing filtering techniques suppress the speckle noise while smearing edges. This problem is partly solved by using nonsquare windows, but it can also generate large errors in many applications. A new windowing algorithm that can overcome the defects of the nonsquare window, by discriminating the edges more precisely with a preliminary terrain classification result, is proposed.X1123sciescopu
Multilook coherence estimation using adaptive weighted window in interferometric SAR
No full textThe coherence between two SAR images is an important factor in the interferometric SAR processing. As a previous step to the phase unwrapping, multilook averaging is widely used as the coherence estimator, and in general, a k x k square window is used. In this letter, it is shown that the performance of the coherence estimator can be improved by using an adaptive weighted window, which is originally developed for SAR speckle reduction. The proposed method was tested using the InSAR data obtained by an automobile-based SAR system.X115sciescopu
Mixed coupling structure for the cross coupling of comb-line filters
No full textA mixed coupling structure is proposed for the cross coupling of a comb-line filter. The proposed structure consists of an electric coupling probe and a magnetic coupling window, and the coupling required for the cross coupling of a cross-coupled filter can be achieved with much easier tuning capability than the structure with only an electric probe. A four-pole comb-line filter is designed and fabricated with the use of the proposed structure, and showed good filter response. (C) 2002 Wiley Periodicals, Inc.X1132sciescopu
Simultaneous reduction of sidelobes and grating lobes by realising nonlinear synthetic wideband waveforms in SAR processing
No full textAn alternative method of SAR signal processing which can be used to simultaneously reduce sidelobes and grating lobes of synthetic wide-band waveforms (SWW) is proposed. The method applies the super spatially variant apodisation technique to each subpulse image of the SWW, and then cuts appropriate portions of the expanded spectra of the subpulses to effectively realise a nonlinear SWW with much better characteristics.X113sciescopu
Least squares phase unwrapping in wavelet domain
No full textLeast squares phase unwrapping is one of the robust techniques used to solve two-dimensional phase unwrapping problems. However, owing to its sparse structure, the convergence rate is very slow, and some practical methods have been applied to improve this condition. In this paper, a new method for solving the least squares two-dimensional phase unwrapping problem is presented. This technique is based on the multiresolution representation of a linear system using the discrete wavelet transform. By applying the wavelet transform, the original system is decomposed into its coarse and fine resolution levels. Fast convergence in separate coarse resolution levels makes the overall system convergence very fast.X1117sciescopu
Alpha-beta-tracking index (alpha-beta-Lambda) tracking filter
No full textAn alpha-beta-tracking index (alpha-beta-Lambda) tracking filter for the single target tracking is proposed for maneuver-following capability. The tracking filter incorporates an estimation technique of the tracking index in the gain approximation algorithm (IEEE Trans. Aerospace Electron. Systems AES-20 (March 1984) 174) and uses a gate-growing method to measure the degree of the target's maneuver. It involves a changeover algorithm which switches over to the conventional alpha-beta filter when the tracking target reaches stationarity, and switches over to the gain approximation algorithm when the tracking target begins to maneuver. The data association algorithm based on comparing matching score makes the gate-growing process reliable in clutter environment and at the same time has the ability of identifying the target, not requiring a separate step. Simulation results show that it is more robust in terms of its ability to minimize the prediction error irrespective of whether the target is in maneuver or not, and whether the target trajectory is linear or not. The proposed alpha-beta-Lambda filter can realize the accuracy of the Kalman filter with an algorithm as simple as the well-known alpha-beta filter. (C) 2002 Elsevier Science B.V. All rights reserved.X1111sciescopu
RIPK3 in necroptosis and cancer
No full textReceptor-interacting protein kinase-3 is essential for the cell death pathway called necroptosis. Necroptosis is activated by the death receptor ligands and pattern recognition receptors of the innate immune system, leading to significant consequences in inflammation and in diseases, particularly cancer. Necroptosis is highly proinflammatory compared with other modes of cell death because cell membrane integrity is lost, resulting in releases of cytokines and damage-associated molecular patterns that potentiate inflammation and activate the immune system. We discuss various ways that necroptosis is triggered along with its potential role in cancer and therapy
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