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Sensors Journal, IEEE

Issue 4 • Date Aug. 2005

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Displaying Results 1 - 25 of 38
  • [Front cover]

    Publication Year: 2005 , Page(s): c1
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    Freely Available from IEEE
  • IEEE Sensors Journal publication information

    Publication Year: 2005 , Page(s): c2
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    Freely Available from IEEE
  • Table of contents

    Publication Year: 2005 , Page(s): 553 - 554
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  • Guest Editorial

    Publication Year: 2005 , Page(s): 555 - 559
    Cited by:  Papers (3)
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  • The "nuclear car wash": a scanner to detect illicit special nuclear material in cargo containers

    Publication Year: 2005 , Page(s): 560 - 564
    Cited by:  Papers (4)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    There is an urgent need to improve the reliability of screening cargo containers for illicit nuclear material that may be hidden there for terrorist purposes. A screening system is described for the detection of fissionable material hidden in maritime cargo containers. The system makes use of a low-intensity neutron beam for producing fission and the detection of the abundant high-energy γ rays emitted in the β-decay of short-lived fission products and β-delayed neutrons. The abundance of the delayed γ rays is almost an order of magnitude larger than that of the delayed neutrons normally used to detect fission, and they are emitted on about the same time scale as the delayed neutrons, i.e., ∼1 min. The energy and temporal distributions of the delayed γ rays provide a unique signature of fission. Because of their high energy, these delayed γ rays penetrate low-Z cargoes much more readily than the delayed neutrons. Coupled with their higher abundance, the signal from the delayed γ rays escaping from the container is predicted to be as much as six decades more intense than the delayed neutron signal, depending upon the type and thickness of the intervening cargo. The γ rays are detected in a large array of scintillators located along the sides of the container as it is moved through them. Measurements have confirmed the signal strength in somewhat idealized experiments and have also identified one interference when 14.5-MeV neutrons from the D, T reaction are used for the interrogation. The interference can be removed easily by the appropriate choice of the neutron source. View full abstract»

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  • Development of a real-time radiological area monitoring network for emergency response at Lawrence Livermore National Laboratory

    Publication Year: 2005 , Page(s): 565 - 573
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1008 KB) |  | HTML iconHTML  

    A real-time radiological sensor network for emergency response was developed and deployed at the Lawrence Livermore National Laboratory (LLNL). The real-time radiological area monitoring (RTRAM) network comprises 16 Geiger-Mueller sensors positioned on the LLNL Livermore site perimeter to continuously monitor for a radiological condition resulting from a terrorist threat to site security and the health and safety of LLNL personnel. The RTRAM network sensor locations coincide with wind sector directions to provide thorough coverage of the one-square-mile site. These low-power sensors are supported by a central command center (CCC) and transmit measurement data back to the CCC computer through the LLNL telecommunications infrastructure. Alarm conditions are identified by comparing current data with predetermined threshold parameters and are validated by comparison with plausible dispersion modeling scenarios and prevailing meteorological conditions. Emergency response personnel are notified of alarm conditions by automatic radio- and computer-based notifications. A secure intranet provides emergency response personnel with current condition assessment data that enable them to direct field response efforts remotely. The RTRAM network has proven to be a reliable system since initial deployment in August 2001, and it maintains stability during inclement weather conditions. View full abstract»

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  • Thin- and thick-film real-time gamma radiation detectors

    Publication Year: 2005 , Page(s): 574 - 580
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB) |  | HTML iconHTML  

    The cruel reality of today's world forces mankind to be alert and prepared for all kinds of terrorist threats, including exposure to radiation. There is a need for cost-effective alternatives to existing commercially available real-time gamma radiation dosimeters. In this paper, numerous oxides such as NiO, CeO2, TeO2, In2O3, SiO, MnO, etc., and their mixtures in different proportions were used as the basis for such a substitute. Thin- and thick-film devices were made in the form of resistors and capacitors, structures with interdigitated electrodes, and pn-junctions. These, in different mixtures, were found to change their sensitivity when exposed to γ-rays. In general, thin-film devices were found to be more sensitive to lower doses of radiation than the counterpart thick films. However, it was experimentally demonstrated that it is possible to fabricate a device that would satisfy the requirement of a particular application, such as the sensitivity to γ-radiation exposure and working dose regions. Based on the above data, these structures might be regarded as a cost-effective alternative for room-temperature real-time γ-radiation dosimetry. View full abstract»

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  • An optical fiber radiation sensor for remote detection of radiological materials

    Publication Year: 2005 , Page(s): 581 - 588
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB) |  | HTML iconHTML  

    This paper demonstrates the feasibility of a portable radiation sensor system that uses the pulsed optically stimulated luminescence technique to remotely interrogate an aluminum oxide (Al2O3:C) radiation sensor via an optical fiber. The objective is to develop a system for applications requiring simple and inexpensive sensors for widespread monitoring of ionizing radiation levels, which can be remotely interrogated at regular periods with little or no human intervention and are easy to install, operate, and maintain. Results on the optimization and performance of the system are presented. The current minimum detectable dose is of the order of 5 μGy, which is already satisfactory for applications such as the monitoring of radioactive plumes from radioactive waste sites. We also discuss potential developments that could decrease the minimum detectable dose to allow radiation doses as low as the background level to be measured over short time intervals, making the system more versatile for detecting radiological materials. View full abstract»

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  • Automatic isotope identifiers and their features

    Publication Year: 2005 , Page(s): 589 - 592
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB) |  | HTML iconHTML  

    Isotope identification instruments fulfill an important role in reducing the risk of a successful radiological or nuclear terrorist attack. However, different users and scenarios require different characteristics in these instruments. We examine the various features such as durability, usability, and algorithm found in commercially available instruments and describe the circumstances that favor their use. View full abstract»

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  • Nuclear detection to prevent or defeat clandestine nuclear attack

    Publication Year: 2005 , Page(s): 593 - 609
    Cited by:  Papers (15)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1592 KB) |  | HTML iconHTML  

    Countering clandestinely delivered nuclear and radiological threats requires a multielement, global, civil/military, system-of-systems approach. One important element is geographically layered, sensor-based detection of threat objects, including radiation detection systems. An effective defense against these threats should take advantage of the latest developments in radiation detection technology. This paper reviews the physics of nuclear detection, and points out areas where improvements can be anticipated, via case studies of technologies such as gamma-ray imaging, advanced radiography, large-area detectors, and active interrogation. View full abstract»

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  • Metalloporphyrins as sensing material for quartz-crystal microbalance nitroaromatics sensors

    Publication Year: 2005 , Page(s): 610 - 615
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB) |  | HTML iconHTML  

    Five octaethylporphyrins (OEP) and tetraphenylporphyrins (TPP): (OEP)InCl, (OEP)MnCl, (OEP)GaCl, (TPP)Pd, and (TPP)RhI have been deposited as sensitive coating onto quartz-crystal microbalances. The sensitivities of the resulting sensors have been measured with respect to 2,4-dinitrotrifluoromethoxybenzene vapors. When exposed to the nitroaromatic compound, a large and significative response is recorded for every tested porphyrin, the detection process being slightly reversible. Along with a good sensitivity, the sensors exhibit an excellent selectivity when common solvents are used as interfering vapors. Among all the studied derivatives, (OEP)MnCl appears as the most sensitive and selective coating. View full abstract»

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  • A novel surface plasmon resonance immunosensor for 2,4,6-trinitrotoluene (TNT) based on indirect competitive immunoreaction: a promising approach for on-site landmine detection

    Publication Year: 2005 , Page(s): 616 - 621
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    A surface plasmon resonance (SPR) immunosensor for the determination of 2,4,6-trinitrotoluene (TNT) has been developed based on the principle of indirect competitive immunoreaction. 2,4,6-trinitrophenol-bovine serum albumin (TNP-BSA) conjugate was immobilized onto a SPR gold chip by means of simple physical adsorption. Binding of anti-TNP antibody with TNP-BSA conjugate was detected based on an increase in resonance angle due to antigen-antibody interaction. Preincubation of anti-TNP antibody with TNT suppresses its interaction with immobilized TNP-BSA conjugate, which leads to a decrease in resonance angle shift. Following the dependence of the resonance angle shift, concentration of TNT was detected. Pepsin solution was used for the regeneration of the sensing surface. The response time for TNT measurement is about 22 min. The immunosensor showed excellent sensitivity to TNT in a wide concentration range from 60 ppt to 1000 ppb with good selectivity, stability, and reproducibility. The proposed system is promising for future application for the on-site detection of landmines. View full abstract»

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  • Ultrahigh-speed chromatography and virtual chemical sensors for detecting explosives and chemical warfare agents

    Publication Year: 2005 , Page(s): 622 - 631
    Cited by:  Papers (9)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1584 KB) |  | HTML iconHTML  

    Chromatographic separation of organic compounds is a well-known method of producing time-resolved chemical spectra or chromatograms. Whereas conventional chromatography using 10-100-m columns is slow, often requiring minutes to hours, ultrahigh-speed chromatography with short resistively heated metal columns requires only seconds. The performance of an ultrahigh-speed gas chromatograph using a surface acoustic wave (SAW) resonator to measure the mass of eluted chemical compounds is described. Closed-loop temperature programming of a resistively heated 1-m capillary column at rates as high as 20°C/s produces near real-time, 10-s chromatograms with chemical spectra peak widths measured in milliseconds. Eluted chemicals are physically adsorbed on an uncoated SAW resonator and frequency deviation versus time produces an eluted mass versus time chromatogram. The derivative of frequency versus time produces a mass/unit time chromatogram of column flux, which is used to measure the retention times of eluted compounds. This paper describes the instrument and process where independent database of chemical spectra are produced by indexing the retention time of specific target chemicals (e.g., explosives and chemical warfare agents) to the retention times of n-alkane standards. It is also shown that assigning time windows centered about specific indices can be used to create arrays of nonoverlapping virtual sensors for specific compounds. Repeated high-speed chromatographic measurements enable virtual sensor readings to be updated in near real time. This work clearly proves that arrays of virtual chemical sensors specific to explosive and chemical warfare agents can detect part per trillion levels of these compounds with high probability of detection and low probability of false alarm. View full abstract»

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  • Simultaneous multianalyte identification of molecular species involved in terrorism using Raman spectroscopy

    Publication Year: 2005 , Page(s): 632 - 640
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB) |  | HTML iconHTML  

    Raman spectroscopy is a form of vibrational spectroscopy that is well suited to the molecular identification of a variety of analytes, including both explosives and biological agents. The technique has been gaining more widespread interest due to improvements in instrumentation, sensitivity, and its ease of use, in comparison to other techniques. In this paper, we describe recent advances in Raman spectroscopy with respect to the detection of high-energy explosives and biological materials. In particular, emphasis is placed on the exploitation of enhancement factors that overcome traditional limitations on sensitivity, namely, surface enhancement and resonance enhancement, functionalization of target analytes, and the use of novel lab-on-a-chip technology. View full abstract»

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  • Electrostatically actuated resonant microcantilever beam in CMOS technology for the detection of chemical weapons

    Publication Year: 2005 , Page(s): 641 - 647
    Cited by:  Papers (38)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB) |  | HTML iconHTML  

    The design, fabrication, and testing of a resonant cantilever beam in complementary metal-oxide semiconductor (CMOS) technology is presented in this paper. The resonant cantilever beam is a gas-sensing device capable of monitoring hazardous vapors and gases at trace concentrations. The new design of the cantilever beam described here includes interdigitated fingers for electrostatic actuation and a piezoresistive Wheatstone bridge design to read out the deflection signal. The reference resistors of the Wheatstone bridge are fabricated on auxiliary beams that are immediately adjacent to the actuated device. The whole device is fabricated using a 0.6-μm, three-metal, double-poly CMOS process, combined with subsequent micromachining steps. A custom polymer layer is applied to the surface of the microcantilever beam to enhance its sorptivity to a chemical nerve agent. Exposing the sensor with the nerve agent simulant dimethylmethylphosphonate (DMMP), provided a demonstrated detection at a concentration of 20 ppb or 0.1 mg/m3. These initial promising results were attained with a relatively simple design, fabricated in standard CMOS, which could offer an inexpensive option for mass production of a miniature chemical detector, which contains on chip electronics integrated to the cantilever beam. View full abstract»

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  • Intrinsic optical-fiber sensor for nerve agent sensing

    Publication Year: 2005 , Page(s): 648 - 655
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1368 KB) |  | HTML iconHTML  

    A novel chemical-sensing technique to detect the nerve agent sarin stimulant dimethylmethylphosphonate (DMMP) is presented. This technique uses a combination of doped polypyrrole as an active chemical material coated on an optical fiber to form an intrinsic fiber-optic sensor. Sensitivity of up to 26 ppm of DMMP with response time of a few seconds is demonstrated. Influence of three different dopants, i.e., 1,5 naphthalene disulphonic acid, anthraquinone 2 sulphonic acid, and hydrochloric acid is investigated for sensor response and sensitivity. Two polymer processing techniques, i.e., in situ deposition and monomer vapor phase deposition is investigated for optimal polypyrrole morphology for DMMP sensitivity. The influence of substrate nature, i.e., hydrophilic and hydrophobic, on sensor sensitivity is studied. Organophosphate specific binding sites have been created in polypyrrole structure using Cu2+ ions to enhance DMMP response. The selectivity issue is addressed by testing the sensor in the presence of other gases like ammonia, water vapor, and acetone which influence the electronic properties of polypyrrole. View full abstract»

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  • Trends in microwave spectroscopy for the detection of chemical agents

    Publication Year: 2005 , Page(s): 656 - 664
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB) |  | HTML iconHTML  

    Recent developments in microwave spectroscopy have encouraged researchers to develop this technique for analytical applications such as environmental monitoring, industrial process control, and homeland defense. This paper presents a general overview of microwave spectroscopy with a focus on aspects relevant for detecting chemical warfare agents (CWAs) and their surrogates. In particular, the high spectral resolution of microwave methods provides exceptional selectivity which is critical for detecting and identifying CWAs given the complex environments and numerous interferents that may obscure measurements by instruments with poor specificity. Ongoing efforts to develop a microwave spectral database of CWAs and improve the quantitative capabilities of Fourier transform microwave spectrometers are discussed. Additionally, future improvements to achieve a field-deployable sensor are presented. View full abstract»

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  • Surface-enhanced Raman scattering detection of chemical and biological agent simulants

    Publication Year: 2005 , Page(s): 665 - 670
    Cited by:  Papers (18)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1456 KB) |  | HTML iconHTML  

    Surface-enhanced Raman scattering spectra of chemical and biological agent simulants, such as dimethyl methylphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, 2-chloroethyl ethylsulfide, bacillus globigii, erwinia herbicola, and bacillus thuringiensis were obtained from silver-oxide film-deposited substrates. Thin AgO films ranging in thickness from 50 to 250 nm were produced by chemical bath deposition onto glass slides. Further Raman intensity enhancements were noticed in UV irradiated surfaces due to photo-induced Ag nanocluster formation, which may provide a possible route to producing highly useful plasmonic sensors for the detection of chemical and biological agents upon visible-light illumination. View full abstract»

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  • Detecting harmful gases using fluctuation-enhanced sensing with Taguchi sensors

    Publication Year: 2005 , Page(s): 671 - 676
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB) |  | HTML iconHTML  

    Sensing techniques are often required to not only be versatile and portable, but also to be able to enhance sensor information. This paper describes and demonstrates a new approach to chemical signal analysis that we call fluctuation-enhanced sensing. It utilizes the entire bandwidth of the sensor signal in contrast to more conventional approaches that rely on the dc response. The new principle holds prospects for significantly reducing the necessary number of sensors in artificial noses and tongues, and it can provide improved sensitivity. View full abstract»

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  • AlGaN/GaN-based diodes and gateless HEMTs for gas and chemical sensing

    Publication Year: 2005 , Page(s): 677 - 680
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB) |  | HTML iconHTML  

    The characteristics of Pt/GaN Schottky diodes and Sc2O3/AlGaN/GaN metal-oxide semiconductor (MOS) diodes as hydrogen and ethylene gas sensors and of gateless AlGaN/GaN high-electron mobility transistors (HEMTs) as polar liquid sensors are reported. At 25°C, a change in forward current of ∼6 mA at a bias of 2 V was obtained in the MOS diodes in response to a change in ambient from pure N2 to 10% H2/ 90% N2. This is approximately double the change in forward current obtained in Pt/GaN Schottky diodes measured under the same conditions. The mechanism appears to be formation of a dipole layer at the oxide/GaN interface that screens some of the piezo-induced channel charge. The MOS-diode response time is limited by the mass transport of gas into the test chamber and not by the diffusion of atomic hydrogen through the metal/oxide stack, even at 25°C. Gateless AlGaN/GaN HEMT structures exhibit large changes in source-drain current upon exposing the gate region to various polar liquids, including block co-polymer solutions. The polar nature of some of these polymer chains lead to a change of surface charges in gate region on the HEMT, producing a change in surface potential at the semiconductor/liquid interface. The nitride sensors appear to be promising for a wide range of chemicals, combustion gases and liquids. View full abstract»

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  • Laser-induced breakdown spectroscopy (LIBS): a promising versatile chemical sensor technology for hazardous material detection

    Publication Year: 2005 , Page(s): 681 - 689
    Cited by:  Papers (41)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB) |  | HTML iconHTML  

    A series of laboratory experiments have been performed highlighting the potential of laser-induced breakdown spectroscopy (LIBS) as a versatile sensor for the detection of terrorist threats. LIBS has multiple attributes that provide the promise of unprecedented performance for hazardous material detection and identification. These include: 1) real-time analysis, 2) high sensitivity, 3) no sample preparation, and 4) the ability to detect all elements and virtually all hazards, both molecular and biological. We have used LIBS to interrogate a variety of different target samples, including explosives, chemical warfare simulants, biological agent simulants, and landmine casings. We have used the acquired spectra to demonstrate discrimination between different chemical warfare simulants, including those on soil backgrounds. A linear correlation technique permits discrimination between an anthrax surrogate and several other biomaterials such as molds and pollens. We also use broadband LIBS to identify landmine casings versus other plastics and environmental clutter materials. A new man-portable LIBS system developed as a collaborative effort between the U.S. Army Research Laboratory and Ocean Optics, Inc., is described and several other schemes for implementing LIBS sensors for homeland security and force protection are discussed. View full abstract»

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  • Characteristics of single neurons cultured on microelectrode arrays in vitro for chemical sensing

    Publication Year: 2005 , Page(s): 690 - 695
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (792 KB) |  | HTML iconHTML  

    In this paper, a single-neuron sensor was developed for chemical agent sensing. Single neurons were positioned over individual microelectrodes using positive dielectrophoretic traps. This enables the continuous extracellular electrophysiological measurements from individual neurons. A remarkably stable recording environment was obtained under the noninvasive conditions. The magnitude and temporal characteristics of an action potential recorded depended on sealing conditions. Then, consecutive sensing experiments were done to testify the stability and repeatability of this kind of single-neuron-based sensor. The responses of neuron-electrode sensor to chemical agent concentration change and to the consecutive experiments were also explored. This sensor exhibits a faster response with the increase of concentration and responds slowly during the consecutive experiments. View full abstract»

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  • Detection of biological and chemical agents using differential mobility spectrometry (DMS) technology

    Publication Year: 2005 , Page(s): 696 - 703
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    With international concern growing over the potential for chemical and biological terrorism, there is an urgent need for a sensor that can quickly and accurately detect chemical and biological agents. Such a sensor needs to be portable, robust, and sensitive, with fast sample analysis time. We will demonstrate the use of a micromachined differential mobility spectrometer (DMS) with these characteristics that can detect multiple agents simultaneously on a time scale of seconds. In this study, we have demonstrated the ability of the DMS to detect Bacillus subtilis spores, a surrogate for Bacillus anthracis spores, the causative agent of anthrax. Pyrolysis was used as the sample introduction method to volatilize the spores before introducing material into the DMS. Additionally, we examined the effect of pyrolysis on B. subtilis spores suspended in sterile water using SDS-PAGE. These experiments showed that the spores must be heated at 650°C or greater for 5 s or at 550°C for at least 10 s to be fragmented into particles considerably smaller than 10 kDa, which the DMS can detect. Several major biomarkers can be easily distinguished above the background of the sterile water in which the spores are suspended, and we hypothesize that additional biomarkers could be liberated by further optimizing conditions. The DMS also has shown promise as a detector for chemical weapon agents, and we have demonstrated the ability of the DMS to detect nerve and blister agent simulants at clinically relevant levels. View full abstract»

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  • Native fluorescence changes induced by bactericidal agents

    Publication Year: 2005 , Page(s): 704 - 711
    Cited by:  Papers (2)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB) |  | HTML iconHTML  

    Steady-state and time-resolved fluorescence spectroscopy were measured for five species of bacteria (Bacillus subtilis, Staphylococcusaureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) subjected to three bactericidal agents, formaldehyde, sodium hypochlorite (bleach), and hydrogen peroxide. For all species, the fluorescence was dominated by tryptophan emission with a fluorescence lifetime that can be described by a bi-exponential decay profile. Application of bleach resulted in an almost total loss of scattering and fluorescence, which indicated that total destruction of proteins and amino acids may have occurred. Hydrogen peroxide decreased the fluorescence intensity and shifted λmax to shorter wavelengths, except in S. aureus, which is resistant to oxidizing agents. The formaldehyde shifted λmax to shorter wavelengths for B. subtilis, S. aureus, E. faecalis, and E. coli. The formaldehyde shortened the lifetime of the slow component and increased the amplitude of the fast component relative to the slow component. This study demonstrates that fluorescence spectroscopy offers a method to evaluate the potential for killing bacteria and decontaminating areas by disinfecting agents. View full abstract»

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  • Chemical warfare agent detection using MEMS-compatible microsensor arrays

    Publication Year: 2005 , Page(s): 712 - 725
    Cited by:  Papers (11)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3768 KB)  

    Microsensors have been fabricated consisting of TiO2 and SnO2 sensing films prepared by chemical vapor deposition (CVD) on microelectromechanical systems array platforms. Response measurements from these devices to the chemical warfare (CW) agents GA (tabun), GB (sarin), and HD (sulfur mustard) at concentrations between 5 nmol/mol (ppb) and 200 ppb in dry air, as well as to CW agent simulants CEES (chloroethyl ethyl sulfide) and DFP (diisopropyl fluorophosphate) between 250 and 3000 ppb, are reported. The microsensors exhibit excellent signal-to-noise and reproducibility. The temperature of each sensor element is independently controlled by embedded microheaters that drive both the CVD process (375°C) and sensor operation at elevated temperatures (325°C-475°C). The concentration-dependent analyte response magnitude is sensitive to conditions under which the sensing films are grown. Sensor stability studies confirm little signal degradation during 14 h of operation. Use of pulsed (200 ms) temperature-programmed sensing over a broad temperature range (20°C-480°C) enhances analyte selectivity, since the resulting signal trace patterns contain primarily kinetic information that is unique for each agent tested. View full abstract»

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Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.