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Same Electrode (same + electrode)

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Medical Sciences	50%

Selected Abstracts

Differential Pulse Voltammetric Determination of Selenocystine Using Selenium-gold Film Modified Electrode

ELECTROANALYSIS, Issue 17 2005
Yan Bai
Abstract Differential pulse voltammetric determination of selenocystine (SeC) using selenium-gold film modified glassy carbon electrode ((Se-Au)/GC) is presented. In 0.10,mol,L,1 KNO3 (pH,3.20) solution, SeC yields a sensitive reduction peak at ,740,mV on (Se-Au)/GC electrode. The peak current has a linear relationship with the concentration of SeC in the range of 5.0×10,8,7.0×10,4,mol,L,1, and a 3, detection limit of SeC is 3.0×10,8,mol,L,1. The relative standard deviation of the reduction current at SeC concentration of 10,6,mol,L,1 is 3.88% (n=8) using the same electrode, and 4.19% when using three modified electrodes prepared at different times. The content of SeC in the selenium-enriched yeast and selenium-enriched tea is determined. The total selenium in ordinary or selenium-enriched tea is determined by DAN fluorescence method. The results indicate that in selenium-enriched yeast about 20% of total selenium is present as SeC and in selenium-enriched tea SeC is the major form of selenoamino acids. The total selenium content in selenium-enriched tea soup is 0.09,,gSe/g accounting by 7% compared with that in selenium-enriched tea. Hence, only a little amount of selenium is utilized by drinking tea, and most selenium still stay in tealeaf. Uncertainty are 22.4% and 16.1% for determination of SeC in selenium-enriched yeast and selenium-enriched tea by differential pulse voltammetry (DPV) on (Se-Au)/GC electrode, respectively. [source]

Hybrid-stabilized solid-shell model of laminated composite piezoelectric structures under non-linear distribution of electric potential through thickness

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 10 2003
Lin Quan Yao
Abstract Eighteen-node solid-shell finite element models have been developed for the analysis of laminated composite plate/shell structures embedded with piezoelectric actuators and sensors. The explicit hybrid stabilization method is employed to formulate stabilization vectors for the uniformly reduced integrated 18-node three-dimensional composite solid element. Unlike conventional piezoelectric elements, the concept of the electric nodes introduced in this paper can effectively eliminate the burden of constraining the equality of the electric potential for the nodes lying on the same electrode. Furthermore, the non-linear distribution of electric potential in the piezoelectric layer is expressed by introducing internal electric potential, which not only can simplify modelling but also obtains the same as the exact solution. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Feasibility of Using Peroneal Nerve Recordings for Deriving Stimulation Timing in a Foot Drop Correction System

NEUROMODULATION, Issue 1 2003
Morten Hansen
Abstract The objective of this research was to demonstrate the potential of using peroneal nerve activity to derive timing control for stimulation in foot drop correction and to attempt recording and stimulation through the same electrode. Two subjects were implanted with cuff electrodes on the peroneal nerve. An input domain was derived from the recorded electroneurogram (ENG) and fed to a detection algorithm based on an Adaptive Logic Network (ALN) for predicting stimulation timing. A switching circuit was furthermore built for switching between stimulator and recorder for combined use of the cuff electrode. The detection was successful, but the accuracy depended on the signal to noise ratio of the recorded ENG. The switching circuit successfully allowed for simultaneous recording and stimulation through the same cuff electrode. We conclude that the peroneal nerve can potentially be used to record sensory information for derivation of a stimulator control signal in a foot drop application, while at the same time being stimulated to activate foot dorsiflexors. [source]

Availability of fluoride from meals given to kindergarten children in Brazil

COMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 2 2006
Marília Afonso Rabelo Buzalaf
Abstract , Objectives:, The aim of this study was to evaluate the amount of fluoride supplied daily in the meals given in 44 public kindergarten schools in Bauru, Brazil. In addition, the fluoride concentration of water supplies and its impact on the amount of fluoride found in the meal samples were also investigated. Methods:, Meal samples and water were collected during 2 weeks (10 working days) in public kindergarten schools. Samples of meals were homogenized with known volumes of deionized water. Fluoride present in meal samples was analyzed with the ion-specific electrode (Orion 9609), after hexamethyldisilazane-facilitated diffusion. Fluoride in water samples was analyzed with the same electrode, after buffering with TISAB II. All the analyses were made in duplicate. Results:, Fluoride analyzed (mean ± SD) was 0.50 ± 0.20 ,g/ml, ranging from nondetectable to 1.42 ,g/ml for water samples (n = 424) and 0.067 ± 0.059 mg, ranging from 0.007 to 0.580 mg for meal samples (n = 431). A weak but significant correlation was observed between the amount of fluoride in meals and fluoride concentration in water supplies (r = 0.139, P = 0.0042). Conclusions:, Despite the seemingly small role played by school meals in the total daily fluoride intake, they can contribute to the total fluoride intake of children on a chronic basis, when in association with other fluoride products. Additionally, the impact of fluoridated public water supply on the final fluoride concentration of the school meals analyzed may be regarded as low. [source]