Synthesis,Biological Evaluation of 1,1‐Diarylethylenes as a Novel Class of Antimitotic Agents

The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B‐ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA‐4 ( 2 e ), isoCA‐4 ( 2 k ) and isoNH₂CA‐4 ( 2 s ) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC₅₀ values of 4, 2 and 1.5 μM , respectively. These derivatives were found to be 10‐fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G₂/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e , 2 k and 2 s on the vessel‐like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors.     

Study of features based on nonlinear dynamical modeling in ECG arrhythmia detection and classification

We present a study of the nonlinear dynamics of electrocardiogram (ECG) signals for arrhythmia characterization. The correlation dimension and largest Lyapunov exponent are used to model the chaotic nature of five different classes of ECG signals. The model parameters are evaluated for a large number of real ECG signals within each class and the results are reported. The presented algorithms allow automatic calculation of the features. The statistical analysis of the calculated features indicates that they differ significantly between normal heart rhythm and the different arrhythmia types and, hence, can be rather useful in ECG arrhythmia detection. On the other hand, the results indicate that the discrimination between different arrhythmia types is difficult using such features. The results of this work are supported by statistical analysis that provides a clear outline for the potential uses and limitations of these features.     

A new real-time retinal tracking system for image-guided laser treatment

A new system is proposed for tracking sensitive areas in the retina for computer-assisted laser treatment of choroidal neovascularization (CNV). The system consists of a fundus camera using red-free illumination mode interfaced to a computer that allows real-time capturing of video input. The first image acquired is used as the reference image and utilized by the treatment physician for treatment planning. A grid of seed contours over the whole image is initiated and allowed to deform by splitting and/or merging according to preset criteria until the whole vessel tree is demarcated. Then, the image is filtered using a one-dimensional Gaussian filter in two perpendicular directions to extract the core areas of such vessels. Faster segmentation can be obtained for subsequent images by automatic registration to compensate for eye movement and saccades. An efficient registration technique is developed whereby some landmarks are detected in the reference frame then tracked in the subsequent frames. Using the relation between these two sets of corresponding points, an optimal transformation can be obtained. The implementation details of proposed strategy are presented and the obtained results indicate that it is suitable for real-time location determination and tracking of treatment positions.     

Design Guidelines for the Noise Optimization of a 0.18 μm CMOS Low-Noise Amplifier

This paper presents the design considerations for the noise optimization of fully integrated tuned low-noise amplifiers (LNA) based on the four noise parameters and two-port noise theory. Specifically, this paper provides the design guidelines for a 0.18 μm CMOS tuned LNA. These guidelines give a useful indication to the design tradeoffs associated with noise figure, power dissipation and gate overdrive voltage for the LNA designed using this technology. As a case study, a 10 GHz LNA has been designed using 0.18 μm CMOS technology for a wireless LAN application. The amplifier has a 2.4 dB noise figure with a −13 dBm third-order input intercept point, while drawing 5 mW from a 1.8 V power supply. The results show that the proposed theoretical contours of constant noise figure which relate the gate overdrive voltage and power dissipation can accurately predict the noise performance of a 0.18 μm CMOS LNA design Ahmed A. Youssef received the B.Sc. (Hon.) and M.Sc. degrees both in electrical engineering from Ain Shams University, Cairo, Egypt, in 1998 and 2002, respectively. Since 2003, he has been with the University of Calgary, AB, Canada, where he is currently working toward the Ph.D. degree in RF integrated circuits and systems. Mr. Youssef has joined the Wireless Research Center at TRLab, Alberta, Canada as a research associate in 2004. His research interests include the analog high speed integrated circuit for the wireless LAN applications. Mr. Youssef is the recipient of the Mobinil Telecommunication Inc. Pre-master Fellowship in 1999. He also received the Young Scientist award at the Maastricht General Assembly of the International Union of Radio Science in 2002 and an Honorable Mention at 2003 in the Symposium of the Microelectronics Research & Development in Canada, Montreal. Mr. Youssef received the Gordon Lewis Hedberg Doctoral Scholarship in 2005.     

Novel Approach to Integration of Numerical Modeling and Field Observations for Deep Excavations

Precedent and observation of performance are an essential part of the design and construction process in geotechnical engineering. For deep urban excavations designers rely on empirical data to estimate potential deformations and impact on surrounding structures. Numerical simulations are also employed to estimate induced ground deformations. Significant resources are dedicated to monitor construction activities and control induced ground deformations. While engineers are able to learn from observations, numerical simulations have been unable to fully benefit from information gained at a given site or prior excavation case histories in the same area. A novel analysis method, self-learning in engineering simulations (SelfSim), is introduced to integrate precedent into numerical simulations. SelfSim is an inverse analysis technique that combines finite element method, biologically inspired material models, and field measurements. SelfSim extracts relevant constitutive soil information from field measurements of excavation response such as lateral wall deformations and surface settlement. The resulting soil model, used in a numerical analysis, provides correct ground deformations and can be used in estimating deformations of similar excavations. The soil model can continuously evolve using additional field information. SelfSim is demonstrated using two excavation case histories in Boston and Chicago.     

A Concern-based Technique for Architecture Modelling Using the UML Package Merge

In this paper, we present a concern-based technique for software architecture modelling. We use the new UML 2 Package Merge relationship as a technique for the separation of concerns. We present the advantages of using the UML Package Merge relationship for software architecture modelling, and we propose a set of extensions for its limitations.     

Communication capabilities of product networks

Instead of providing separate solutions for each individual network, a unified theory is desirable to cover the study of a class of networks. Cartesian product graphs provide a common framework to investigate the performance of several individual networks. This paper addresses communication capabilities of product networks. Communication cost is generally characterized by the diameter, the average distance, the total number of paths, the traffic intensity, the saturation level, the queue length in each node, the communication delay and the network throughput. The diameter and average distance of product networks have been studied. However, no work has addressed the remaining measures for product networks. This paper presents a unified theory to evaluate the traffic intensity and the saturation level of product networks. We have theoretically computed the traffic intensity and the saturation level. Intensive simulations have been conducted to validate the analytical results and to compute the other measures for different workloads, different networks, and different network sizes. Examples of product networks that have been investigated are multidimensional meshes, multidimensional toruses, and r‐ary n‐cube networks. We have also shown that the structure (geometry) of a network is a primary factor for network high performance. For meshes and toruses, square networks present an optimal structure. While in case of an r‐ary n‐cubes, networks with higher radix outperform those with smaller radix. In particular, cross‐cubes (4‐ary n‐cube) are shown to perform better than binary cubes. This revised version was published online in June 2006 with corrections to the Cover Date.     

An effective approach to teach design of experiments (DOE) using calculation-and-analysis worksheets and computerized spreadsheets

The École de technologie supérieure (ÉTS) of the University of Québec is offering Design of Experiments (DOE) courses for more than a decade within its undergraduate certificate program of Quality Management and Assurance (QMA). Previous teaching experiences showed that the conceptual aspects of DOE has been somehow difficult to be rapidly and efficiently assimilated by the part-time adult students. Although DOE have proved to be very effective in improving quality throught process parameters' optimization, many engineers rejected the idea of applying the technique on the floor level because of the conceptual and statistical barriers. For these reasons, the authors have developed and introduced a new teaching approach in order to clarify the conceptual aspects and simplify the mechanics underlying the DOE techniques and, therefore, help the students to better understand and implement DOE at the work place. The approach is mainly based on the use of simple and straight forward calculation-and-analysis worksheets that have been developed for the most commonly used experimental designs (full factorial, screening factorial, screening fractionnal factorial and Taguchi arrays). In this paper, the authors present the approach with a sample of the most pertinent calculation-and-analysis worksheets used along with a practical example.     

On the Electromagnetic Interference Fringes Method in Geophysical Prospecting Applications

The method of electromagnetic interference fringes for the prospecting of conductive subsurfaces inside the earth is reviewed. The fields radiated by an electrically small horizontal loop situated on the earth's surface are derived and expressed in terms of different interfering wave components. The variable distance interference fringes (VDIF) method and the variable frequency interference (VFIF) method of prospecting are considered, and an interpretation procedure using the data obtained from both methods is suggested.     

Dependence of the optimal phase demodulator on statistical parameters

In this note we show that the filtering phase error variance for the optimal phase demodulator is independent of plant noise spectral density and depends only on output noise-to-signal ratio for the optimal phase demodulator. Hence, our Monte Carlo results are complete.