Radix-4 Vectoring CORDIC Algorithm and Architectures

In this work we extend the radix-4 CORDIC algorithm to the vectoring mode (the radix-4 CORDIC algorithm was proposed recently by the authors for the rotation mode). The extension to the vectoring mode is not straightforward, since the digit selection function is more complex in the vectoring case than in the rotation case; as in the rotation mode, the scale factor is not constant. Although the radix-4 CORDIC algorithm in vectoring mode has a similar recurrence as the radix-4 division algorithm, there are specific issues concerning the vectoring algorithm that demand dedicated study. We present the digit selection for nonredundant and redundant arithmetic (following two different approaches: arithmetic comparisons and table look-up), the computation and compensation of the scale factor, and the implementation of the algorithm (with both types of digit selection) in a word-serial architecture. When compared with conventional radix-2 (redundant and non-redundant) architectures, the radix-4 algorithms present a significant speed up for angle calculation. For the computation of the magnitude the speed up is very slight, due to the nonconstant scale factor in the radix-4 algorithm.     

Preparation and characterization of β‐cyclodextrin‐linked chitosan microparticles

Hydrophobically modified chitosan containing β‐cyclodextrin (CD) units was synthesized by using tosylated β‐CD. The final product was characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis and TGA, and rheometry. The polymer bearing β‐CD moieties was used to obtain crosslinked microparticles by spray‐drying which could then be used in a controlled release system for drugs. FTIR confirmed the formation of an amide linkage between cyclodextrin and chitosan. As fluorescence spectroscopy demonstrated, hydrophobic microenvironments were formed by chitosan bearing cyclodextrin in solution at lower concentrations than for chitosan. Rheometry and FTIR showed the crosslinking of the new polymer using genipin, a molecule of natural origin. Microspheres (MS) obtained by spray‐drying showed narrow size distribution when β‐CD was grafted onto chitosan and ξ‐potential of MS was slightly lower although it remained positive. In conclusion, β‐CD linked chitosan polymer can be considered as a very promising controlled drug delivery system for drugs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A multiplatform Java wrapper for the BioAPI framework

We present a solution for the development of multiplatform and web-oriented Java applications for biometric authentication based on the BioAPI framework. Our proposal is a single Java Native Interface wrapper that is compatible with the BioAPI instantiations of Windows and Linux/Unix operating systems. Following a study of existing wrappers, we extended the open-source Linux/Unix wrapper to include Windows support. In order to show the utility of this multiplatform Java wrapper, we discuss some of its possible uses and present a real-life application.     

Very-High Radix CORDIC Rotation Based on Selection by Rounding

A very-high radix algorithm and implementation for CORDIC rotation in circular and hyperbolic coordinates is presented. The selection function consists of rounding the residual. It is shown that this assures convergence from the second iteration on. For the first iteration, the selection is done by table, using a lower radix than for the remaining iterations. The compensation of the variable scale factor is done by computing the logarithm of the scale factor and performing the compensation by an exponential. Estimations of the delay for 32-bit and 64-bit precision show a substantial speed up when compared to low radix implementations. The proposed algorithm is also compared with previously proposed very-high radix ones, and significant advantages are identified.     

A novel design of a two operand normalization circuit

This paper presents a new design for two operand normalization. The two operand normalization operation involves the normalization of at least one of two operands by left shifting both by the same amount. Our design performs the computation of the shift by making an OR of the bits of both operands in a tree network, encoding the position of the first nonzero bit. The encoded position is obtained most significant bit first, and then there is an overlapping with the shifting operation. The design we propose replaces two leading zero detector circuits and a comparator, that are present in the conventional approach. Our scheme demonstrates to be more area efficient than the conventional one. The circuit we propose is useful in floating point complex multiplication and COordinate Rotation DIgital Computer (CORDIC) processors     

Effects of Aging and Hypercholesterolemia on Oxidative Stress and DNA Damage in Bone Marrow Mononuclear Cells in Apolipoprotein E-deficient Mice

Recent evidence from apolipoprotein E-deficient (apoE^−/−) mice shows that aging and atherosclerosis are closely associated with increased oxidative stress and DNA damage in some cells and tissues. However, bone marrow cells, which are physiologically involved in tissue repair have not yet been investigated. In the present study, we evaluated the influence of aging and hypercholesterolemia on oxidative stress, DNA damage and apoptosis in bone marrow cells from young and aged apoE^−/− mice compared with age-matched wild-type C57BL/6 (C57) mice, using the comet assay and flow cytometry. The production of both superoxide and hydrogen peroxide in bone marrow cells was higher in young apoE^−/− mice than in age-matched C57 mice, and reactive oxygen species were increased in aged C57 and apoE^−/− mice. Similar results were observed when we analyzed the DNA damage and apoptosis. Our data showed that both aging and hypercholesterolemia induce the increased production of oxidative stress and consequently DNA damage and apoptosis in bone marrow cells. This study is the first to demonstrate a functionality decrease of the bone marrow, which is a fundamental extra-arterial source of the cells involved in vascular injury repair.     

Effectiveness of personalized written feedback through a mail intervention for smoking cessation: A randomized-controlled trial in Spanish smokers.

This study evaluated the effects of written feedback adapted to a self-help mail intervention. The efficacy of the standard mail intervention treatment was 37% at the end of treatment, 22% at the 3-month follow-up, 19% at the 6-month follow-up, and 13% at the 12-month follow-up. In contrast, the standard mail program combined with personalized written feedback resulted in an efficacy of 51% at the end of treatment, 37% at the 3-month follow-up, 32% at the 6-month follow-up, and 27% at the 12-month follow-up. Both groups were significantly different from the control group at the end of treatment (0%), at the 3-month follow-up (1%), and at the 6-month follow-up (1%). There was a significant reduction in the number of cigarettes smoked daily among continuing smokers under both experimental conditions. The authors conclude that written feedback substantially increases abstinence rates when it is applied following similar guidelines to those used in clinical settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)