Selective Ion Extraction for High Throughput Screening with a Microfluidic Enzyme Assay

This proof-of-concept paper describes the application of selective ion extraction to an assay of protein kinase A on a microfluidic chip platform. Selective ion extraction is a flux balance technique, where a combination of independent pressure control and voltage are used to selectively extract one ion from a mixture. The assay product is completely separated and diverted into a separate channel from the waste stream containing the unconverted substrate and enzyme. By detecting only product, background noise generated by the substrate is removed which increases the signal to noise ratio and assay sensitivity. This technique is intended for adapting kinase or protease assays with low conversion rates to an on-chip reaction format for HTS screening.     

Pose estimation from a two-dimensional view by use of composite correlation filters and neural networks

We present a technique to estimate the pose of a three-dimensional object from a two-dimensional view. We first compute the correlation between the unknown image and several synthetic-discriminant-function filters constructed with known views of the object. We consider both linear and nonlinear correlations. The filters are constructed in such a way that the obtained correlation values depend on the pose parameters. We show that this dependence is not perfectly linear, in particular for nonlinear correlation. Therefore we use a two-layer neural network to retrieve the pose parameters from the correlation values. We demonstrate the technique by simultaneously estimating the in-plane and out-of-plane orientations of an airplane within an 8-deg portion. We show that a nonlinear correlation is necessary to identify the object and also to estimate its pose. On the other hand, linear correlation is more accurate and more robust. A combination of linear and nonlinear correlations gives the best results.     

Step-Growth Polymerization of 4-(1-Naphthyl)-1,2,4-triazolidine-3,5-dione with Diisocyanates

Summary We have synthesized 4-(1-naphthyl)-1,2,4-triazolidine-3,5-dione (4-NTD) in high yield and purity from 1-naphthyl isocyanate and used it as a new monomer for polymer synthesis. A series of novel naphthalene-containing polyureas have been successfully prepared from 4-NTD with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and toluene-2,4-diisocyanate (TDI) in N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP) solution in the presence of pyridine, triethylamine or dibutyltin dilurate as catalysts. Some physical properties and structural characterization of these novel polyureas are reported. Fluorimetric studies of the new monomer, model compound as well as polymers were also investigated.     

Lightfastness and flash photolysis of hydroxyanthraquinones

The photostability of the commercially important dye 1,2-dihydroxyanthraquinone (alizarin) is compared with that of four other structurally related hydroxyanthraquinones in both solution and polymer substrates. In solution the flash photolysis experiments showed that in a polar solvent, 2-propanol, the 1,2-hydroxy derivative is the least reactive. A similar trend in lightfastness (LF) is found when the dyes are applied to the highly polar substrate nylon-6,6.     

From curve design algorithms to the design of rigid body motions

We discuss the following problem, which arises in computer animation and robot motion planning: given are N positions or keyframes (t_i) of a moving body ³ at time instances t_i. Compute a smooth rigid body motion (t) that interpolates or approximates the given positions (t_i) such that chosen feature points of the moving system run on smooth paths. We present an algorithm that can be considered as a transfer principle from curve design algorithms to motion design. The algorithm relies on known curve design algorithms and on registration techniques from computer vision. We prove that the motion generated in this way is of the same smoothness as the curve design algorithm employed. Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00371-003-0221-3To the memory of Peter Steiner     

Secure three-dimensional data transmission and display

An optical three-dimensional (3D) display system interfaced with digital data transmission is proposed. In this system, an original 3D object is encrypted by use of a random phase mask and then the encrypted pattern is recorded as a digital hologram. The digital hologram key is also recorded for optical decryption. Both the encrypted digital hologram and the digital hologram key are transmitted to a receiver through a conventional communication data channel. At the receiver, the 3D scene is reconstructed and displayed optically in a retrieval system based on a joint-transform correlation. Experimental results are presented. We investigate the influence of quantization of the joint power spectrum in the optical correlator on the quality of the reconstructed image.     

Sampling in the light of Wigner distribution

We propose a new method for analysis of the sampling and reconstruction conditions of real and complex signals by use of the Wigner domain. It is shown that the Wigner domain may provide a better understanding of the sampling process than the traditional Fourier domain. For example, it explains how certain non-bandlimited complex functions can be sampled and perfectly reconstructed. On the basis of observations in the Wigner domain, we derive a generalization to the Nyquist sampling criterion. By using this criterion, we demonstrate simple preprocessing operations that can adapt a signal that does not fulfill the Nyquist sampling criterion. The preprocessing operations demonstrated can be easily implemented by optical means.     

Development of a Rapid Prototyping System using Response Surface Methodology

This case study presents an investigation of the relationships between eight process operating variables (factors) and five part performance measures (responses) in a rapid prototyping system. The use of fractional factorial, single‐factor foldover, and central composite designs is demonstrated. Polynomial regression models are constructed for each response, followed by a desirability function model. Canonical and ridge analyses are used to identify a group of factor settings that simultaneously produce improved performance for all responses. Copyright © 2006 John Wiley & Sons, Ltd.     

Reconstruction of water balance components using tree‐ring proxy records

Long‐term hydrological data are important elements in water resource planning and management. The hydrometric data record period in Iran varies from a few years to about 60 years; generally inadequate for long‐term planning. Reconstruction of meteorological data using tree‐ring proxy records is a viable technique in extending meteorological data in the past (i.e. backcasting). This study reconstructed the precipitation and temperature data based on the tree‐ring proxy records over the 1710–2000 period in Kermanshah Province, Iran. Furthermore, using WASMOD water balance model, streamflow and other hydrological water balance components were reconstructed. In the study basin, the average monthly streamflows were determined as 6.25, 5.56 and 5.50 mm for the eighteenth, nineteenth and twentieth centuries, respectively. While the eighteenth century was the wettest, in nineteenth and twentieth centuries the streamflow reduced by an average of 14% compared to that of the eighteenth century.