New Sensor (new + sensor)

Distribution by Scientific Domains

Selected Abstracts

A Glassy Carbon Electrode Modified with Multiwalled Carbon Nanotube/Chitosan Composite as a New Sensor for Simultaneous Determination of Acetaminophen and Mefenamic Acid in Pharmaceutical Preparations and Biological Samples

Ali Babaei
Abstract A new chemically modified electrode is constructed based on multiwalled carbon nanotube/chitosan modified glassy carbon electrode (MWCNTs-CHT/GCE) for simultaneous determination of acetaminophen (ACT) and mefenamic acid (MEF) in aqueous buffered media. The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. Application of DPV method showed that the linear relationship between oxidation peak current and concentration of ACT and MEF were 1,,M to 145,,M, and 4,,M to 200,,M, respectively. The analytical performance of this sensor has been evaluated for detection of ACT and MEF in human serum, human urine and a pharmaceutical preparation with satisfactory results. [source]

ChemInform Abstract: Perovskite-Type Oxide-Based Electrode: A New Sensor for Hydrogen-Phosphate Ion.

CHEMINFORM, Issue 5 2001
Youichi Shimizu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Simultaneous Determination of Cadmium, Lead, Copper and Mercury Ions Using Organofunctionalized SBA-15 Nanostructured Silica Modified Graphite,Polyurethane Composite Electrode

Ivana Cesarino
Abstract A new sensor has been developed for the simultaneous detection of cadmium, lead, copper and mercury, using differential pulse and square wave anodic stripping voltammetry (DPASV and SWASV) at a graphite,polyurethane composite electrode with SBA-15 silica organofunctionalized with 2-benzothiazolethiol as bulk modifier. The heavy metal ions were preconcentrated on the surface of the modified electrode at ,1.1,V vs. SCE where they complex with 2-benzothiazolethiol and are reduced to the metals, and are then reoxidized. Optimum SWASV conditions lead to nanomolar detection limits and simultaneous determination of Cd2+, Pb2+, Cu2+ and Hg2+ in natural waters was achieved. [source]

Electrochemical Characterization of In Situ Functionalized Gold Cysteamine Self-Assembled Monolayer with 4-Formylphenylboronic Acid for Detection of Dopamine

Karimi Shervedani
Abstract Functionalization of gold cysteamine (AuCA) self-assembled monolayer with 4-formylphenylboronic acid (BA) via Schiff's base formation, through in situ method to fabricate Au-CA-BA electrode is presented and described. The fabricated electrode was used as a novel sensor for accumulation and determination of dopamine (DA). The accumulation of DA as a diol on the topside of Au-CA-BA as a Lewis acid, was performed via esterification (AuCABADA), and followed for determination of DA. Functionalization, characterization, and determination steps were probed by electrochemical methods like cyclic voltammetry and electrochemical impedance spectroscopy. The data will be presented and discussed from which a new sensor for DA is introduced. [source]

Glutathione Peroxidase-Based Amperometric Biosensor for the Detection of S -Nitrosothiols

Mustafa Musameh
Abstract A new biosensor is described for the detection of S -nitrosothiols (RSNOs) based on their decomposition by immobilized glutathione peroxidase (GPx), an enzyme containing selenocysteine residue that catalytically produces nitric oxide (NO) from RSNOs. The enzyme is entrapped at the distal tip of a planar amperometric NO sensor. The new biosensor shows good sensitivity, linearity, reversibility, and response times towards various RSNO species in PBS buffer, pH,7.4 . In most cases, the response time is less than 5,min, and the response is linear up to 6 ,M of the tested RSNO species. The lowest detection limit is obtained for S -nitrosocysteine (CysNO), at approx. 0.2,,M. The biosensor's sensitivity is not affected by the addition of EDTA as a chelating agent; an advantage over other potential catalytic enzymes that contain copper ion centers, such as CuZn-superoxide dismutase and xanthine oxidase. However, lifetime of the new sensor is limited, with sensitivity decrease of 50% after two days of use. Nonetheless, the new amperometric GPx based RSNO sensor could prove useful for detecting relative RSNO levels in biological samples, including whole blood. [source]

Microemulsion polymerization of cationic pyrroles bearing an imidazolum-ionic liquid moiety

Jie Zhao
Abstract A cationic pyrrole derivative, N -(4-butyl-(1-methylimidazole)) pyrrole bromide (Py-Br) bearing an imidazolium-type ionic liquid moiety was synthesized. Microemulsion polymerization of Py-Br in water/oil microemulsions produced poly(N -(4-butyl-(1-methylimidazole)) pyrrole bromide) (PPy-Br) nanoparticles. The bromide anion of the resultant PPy-Br nanoparticles was exchanged in water with different anions, including BF and PF to produce new nanoparticles bearing different counteranions. The results of thermal analysis indicate that the thermal stability of cationic PPy nanoparticles strongly depends on the nature of counteranion. As an application, water-soluble PPy-Br with fine fluorescence property was used as a new sensor for DNA detection. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 746,753, 2009 [source]

Performance of a Rate Responsive Accelerometer-Based Pacemaker with Autocalibration During Standardized Exercise and Recovery

GARRIGUE, S., et al.: Performance of a Rate Responsive Accelerometer-Based Pacemaker with Autocal-ibration During Standardized Exercise and Recovery. The rate responsiveness of a single chamber, accelerometer-based pacemaker with an autocalibration function (Opus G VVIR pacemaker, ELA Medical) was studied with a daily life protocol developed to automatically optimize the programming of accelerometer-based sensors. This new sensor was compared with two other body activity sensors that were manually optimized patient by patient. Forty-three pacemaker recipients (mean age 71 ± 11 years), paced > 95% of the time, underwent a daily life protocol consisting of rapid walking for 6 minutes (W), climbing upstairs for 1.5 minutes (U), and downstairs for 1.5 minutes (D), alternated by recovery phases. The results were compared with performances measured in a control population of healthy subjects and in two paced patient populations (one equipped with a Dash Intermedics VVIR pacemaker and the other equipped with a Sensolog III Pacesetter/St. Jude VVIR pacemaker). Sex distribution and mean age between paced patients and control subjects were statistically comparable. The mean heart rate achieved by all paced patients at each time sample was compared with the normograms, assigning acceleration (slope) and rate (rate) scores for exercise and recovery phases. Scores ranged from -10 (hypochronotropic) to +10 (hyperchronotropic). Zero represents exact concordance with the responses of healthy individuals, and values between -2.5 and +2.5 were considered statistically similar to normal. During W, although the overall performances of the Dash, Sensolog, and Opus G did not statistically differ from healthy controls, the scores obtained by the Opus G were significantly closer to controls than those of the two other pacemakers (P = 0.02). For U, the three sensors were hypochronotropic (P = 0.03), though the Opus G was associated with a heart rate response closer to that of healthy controls (P = 0.04). D provided similar mean heart rate scores for the Opus G and the Dash compared with healthy controls, in contrast with the hyperchronotropic behavior of the Sensolog (P = 0.02). Opus G revealed a physiological modulation of the heart rate for W and D tests with a slightly hypochronotropic behavior during U. The Opus G autocalibration function provided daily life performances closer to those of healthy controls than two other pacemakers equipped with a body activity sensor that were manually optimized. [source]

Progress in the Development of a High Performance Airborne Digital Sensor

P. Fricker
Joint development work by LH Systems and Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center) has produced encouraging results using forward, nadir and backward looking linear arrays on the focal plane to provide panchromatic imagery and geometric information, supplemented by further arrays to acquire multispectral imagery suitable for both high precision photogrammetric mapping and image processing for interpretative purposes. The geometric characteristics of line scanner imagery necessitate line-by-line rectification for aircraft tilts and shifts. Satisfactory execution of this process is enhanced by using supplementary data from high performance, on-board GPS and inertial measurement systems. Similarly, high demands are placed on other sub-systems, such as the camera mount, lens, electronics and storage technology. In addition to rectification for aircraft tilts and shifts, rectification for terrain characteristics is also required in order to generate colour and false colour composite images, since the various multispectral arrays are in different places on the focal plane. The special geometry affects triangulation. Thereafter, the imagery can be processed using existing software packages from both photogrammetry and remote sensing. The concept has been demonstrated in several successful test flights and the production model is scheduled for market introduction at the ISPRS Congress in July 2000. The imagery from the new sensor will fulfil many market requirements between the highest resolution film imagery (<0.1 m) and high resolution space imagery (1m to 10 m). The sensor's unique blend of multispectral information with high quality geometric information will give rise to numerous new applications. [source]

Postprandial hyperglycaemia in type 2 diabetes: pathophysiological aspects, teleological notions and flags for clinical practice

Eleni I. Boutati
Abstract Type 2 diabetes subjects carry an excess risk for micro- and macrovascular disease and a higher cardiovascular morbidity and mortality rate. The beneficial impact of tight glycaemic control,evidenced by the integrated marker of fasting glucose and postprandial glucose values, the HbA1c,for the prevention of microvascular complications is definitely confirmed. Over the past few years, several studies have identified postprandial hyperglycaemia as a better predictor of cardiovascular or even of all-cause mortality, as well as an independent risk factor for atherosclerosis. The continuous glucose monitoring could offer a rationale means for the detection of postprandial hyperglycaemia and ultimately for its effective management. Advances in technology keep a promise for a reliable, convenient and closer to the idea of the artificial endocrine pancreas glucose sensor. Subcutaneous glucose levels charted by one of the new sensors were found to be well correlated with venous glucose measurements. Intervention for a healthy lifestyle is frequently hampered by patients' poor compliance. The availability of diverse antidiabetic agents provides options for targeting the glycaemic goal and a choice more fitted to the particularized pathophysiology of each individual subject. Drugs targeting postprandial glycaemia may prove to represent the ,sine qua non' for the ,return' of postprandial glucose values at a ,non-deleterious' threshold, either as monotherapy for the early stages of the disease or as combination therapy later in the progression of diabetes. Copyright © 2004 John Wiley & Sons, Ltd. [source]

GaN-based Schottky diodes for hydrogen sensing in transformer oil

Peter Sandvik
Abstract We report the demonstration of robust, GaN-based hydrogen sensors for use directly in transformer oil. These 1 mm2 Schottky diodes were immersed in a closed loop with Voltesso insulating oil for 21 months of continuous testing. They showed good reproducibility in response to hydrogen gases, while exposed to varying temperatures. We will briefly discuss the transformer monitoring application, the device design and fabrication process, and the sensor performance from 21-months of testing. Transfer functions from oil temperature and dissolved gas concentration have been quantified, and those will be briefly discussed. These new sensors offer a novel alternative to electrochemical cell-based sensors for various applications. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]