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Sensors, Volume 7, Issue 7 (July 2007) – 19 articles , Pages 1028-1342

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10733 KiB  
Article
Effects of Palladium Loading on the Response of Thick Film Flame-made ZnO Gas Sensor for Detection of Ethanol Vapor
by Chaikarn Liewhiran and Sukon Phanichphant
Sensors 2007, 7(7), 1159-1184; https://doi.org/10.3390/s7071159 - 26 Jul 2007
Cited by 52 | Viewed by 10477
Abstract
ZnO nanoparticles doped with 0-5 mol% Pd were successfully produced in asingle step by flame spray pyrolysis (FSP) using zinc naphthenate and palladium (II)acetylacetonate dissolved in toluene-acetonitrile (80:20 vol%) as precursors. The effect ofPd loading on the ethanol gas sensing performance of the [...] Read more.
ZnO nanoparticles doped with 0-5 mol% Pd were successfully produced in asingle step by flame spray pyrolysis (FSP) using zinc naphthenate and palladium (II)acetylacetonate dissolved in toluene-acetonitrile (80:20 vol%) as precursors. The effect ofPd loading on the ethanol gas sensing performance of the ZnO nanoparticles and thecrystalline sizes were investigated. The particle properties were analyzed by XRD, BET,AFM, SEM (EDS line scan mode), TEM, STEM, EDS, and CO-pulse chemisorptionmeasurements. A trend of an increase in specific surface area of samples and a decrease inthe dBET with increasing Pd concentrations was noted. ZnO nanoparticles were observed asparticles presenting clear spheroidal, hexagonal and rod-like morphologies. The sizes ofZnO spheroidal and hexagonal particle crystallites were in the 10-20 nm range. ZnOnanorods were in the range of 10-20 nm in width and 20-50 nm in length. The size of Pdnanoparticles increased and Pd-dispersion% decreased with increasing Pd concentrations.The sensing films were produced by mixing the particles into an organic paste composedof terpineol and ethyl cellulose as a vehicle binder. The paste was doctor-bladed ontoAl2O3 substrates interdigitated with Au electrodes. The film morphology was analyzed bySEM and EDS analyses. The gas sensing of ethanol (25-250 ppm) was studied in dry air at400°C. The oxidation of ethanol on the sensing surface of the semiconductor wasconfirmed by MS. A well-dispersed of 1 mol%Pd/ZnO films showed the highest sensitivityand the fastest response time (within seconds). Full article
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1691 KiB  
Article
Land Use and Land Cover Change in Guangzhou, China, from 1998 to 2003, Based on Landsat TM /ETM+ Imagery
by Fenglei Fan, Qihao Weng and Yunpeng Wang
Sensors 2007, 7(7), 1323-1342; https://doi.org/10.3390/s7071323 - 25 Jul 2007
Cited by 130 | Viewed by 25133
Abstract
Land use and land cover change is a major issue in global environment change,and is especially significant in rapidly developing regions in the world. With its economicdevelopment, population growth, and urbanization, Guangzhou, a major metropolitan inSouth China, have experienced a dramatic land use [...] Read more.
Land use and land cover change is a major issue in global environment change,and is especially significant in rapidly developing regions in the world. With its economicdevelopment, population growth, and urbanization, Guangzhou, a major metropolitan inSouth China, have experienced a dramatic land use and land cover (LULC) change over thepast 30 years. Fast LULC change have resulted in degradation of its ecosystems andaffected adversely the environment. It is urgently needed to monitor its LULC changes andto analyses the consequences of these changes in order to provide information for policy-makers to support sustainable development. This study employed two Landsat TM/ETM images in the dry season to detect LULC patterns in 1998 and 2003, and to examine LULCchanges during the period from 1998 to 2003. The type, rate, and pattern of the changesamong five counties of Guangzhou Municipality were analyzed in details by post-classification method. LULC conversion matrix was produced for each county in order toexplore and explain the urban expansion and cropland loss, the most significant types ofLULC change. Land use conversion matrixes of five counties were discussed respectivelyin order to explore and explain the inherence of land use change. The results showed thaturban expansion in these five counties kept an even rate of increase, while substantialamount of cropland vanished during the period. It is also noted that the conversion between cropland and orchard land was intensive. Forest land became the main source of new croplands. Full article
(This article belongs to the Special Issue Sensors for Urban Environmental Monitoring)
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143 KiB  
Communication
Innovative Detection System of Ochratoxin A by Thin Film Photodiodes
by Domenico Caputo, Gianpiero De Cesare, Corrado Fanelli, Augusto Nascetti, Alessandra Ricelli and Riccardo Scipinotti
Sensors 2007, 7(7), 1317-1322; https://doi.org/10.3390/s7071317 - 25 Jul 2007
Cited by 22 | Viewed by 21293
Abstract
In this work we present, for the first time, a rapid, compact and innovativemethod for detection of Ochratoxin A (OTA) based on hydrogenated amorphous silicon (a-Si:H) sensors. 2 μl of acidified toluene containing OTA at different concentrations werespotted on the silica side of [...] Read more.
In this work we present, for the first time, a rapid, compact and innovativemethod for detection of Ochratoxin A (OTA) based on hydrogenated amorphous silicon (a-Si:H) sensors. 2 μl of acidified toluene containing OTA at different concentrations werespotted on the silica side of a High Performance Thin Layer Cromatography plate andaligned with a a-Si:H p-i-n photodiode deposited by Plasma Enhanced Chemical VaporDeposition on a different glass substrate. As an UV radiation excites the mycotoxin, the re-emitted light is detected by the a-Si:H sensor. Results show a very good linearity betweenOTA concentration and the sensor photocurrent over almost three orders of magnitude. Theminimum detected OTA concentration is equal to 0.1ng, showing that the presented systemhas the potential for a low cost system suitable for the early detection of toxins in foods. Full article
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244 KiB  
Article
Software and Equipment for Remote Testing of Sensors
by Barbara Brezovec and Vojko Matko
Sensors 2007, 7(7), 1306-1316; https://doi.org/10.3390/s7071306 - 20 Jul 2007
Cited by 4 | Viewed by 13747
Abstract
An improved approach for remote testing of elements and systems is presentedin this article. To ensure high reliability of products, tests must be done in the productionphase to detect possible errors in working mode. Because environmental testing involveslong-term processes the possibility of remote [...] Read more.
An improved approach for remote testing of elements and systems is presentedin this article. To ensure high reliability of products, tests must be done in the productionphase to detect possible errors in working mode. Because environmental testing involveslong-term processes the possibility of remote observation and remote controlling of tests isvery useful solution. The concept is to connect the testing chamber with a personalcomputer, create a reliable driver and control it remotely over the local network or Internetfrom other client. It is designed for performing tests on wide area of sensors and sensorbased systems. Full article
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801 KiB  
Article
Ubiquitous Computing Services Discovery and Execution Using a Novel Intelligent Web Services Algorithm
by Okkyung Choi and SangYong Han
Sensors 2007, 7(7), 1287-1305; https://doi.org/10.3390/s7071287 - 20 Jul 2007
Cited by 11 | Viewed by 7972
Abstract
Ubiquitous Computing makes it possible to determine in real time the locationand situations of service requesters in a web service environment as it enables access tocomputers at any time and in any place. Though research on various aspects of ubiquitouscommerce is progressing at [...] Read more.
Ubiquitous Computing makes it possible to determine in real time the locationand situations of service requesters in a web service environment as it enables access tocomputers at any time and in any place. Though research on various aspects of ubiquitouscommerce is progressing at enterprises and research centers, both domestically andoverseas, analysis of a customer’s personal preferences based on semantic web and rulebased services using semantics is not currently being conducted. This paper proposes aUbiquitous Computing Services System that enables a rule based search as well assemantics based search to support the fact that the electronic space and the physical spacecan be combined into one and the real time search for web services and the construction ofefficient web services thus become possible. Full article
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459 KiB  
Article
Hazards of Secondary Bromadiolone Intoxications Evaluated using High-performance Liquid Chromatography with Electrochemical Detection
by Sona Krizkova, Miroslava Beklova, Jiri Pikula, Vojtech Adam, Ales Horna and René Kizek
Sensors 2007, 7(7), 1271-1286; https://doi.org/10.3390/s7071271 - 20 Jul 2007
Cited by 16 | Viewed by 12449
Abstract
This study reported on the possibility of intoxications of non-target wild animalsassociated with use of bromadiolone as the active component of rodenticides withanticoagulation effects. A laboratory test was done with earthworms were exposed tobromadiolone-containing granules under the conditions specified in the modified OECD207 [...] Read more.
This study reported on the possibility of intoxications of non-target wild animalsassociated with use of bromadiolone as the active component of rodenticides withanticoagulation effects. A laboratory test was done with earthworms were exposed tobromadiolone-containing granules under the conditions specified in the modified OECD207 guideline. No mortality of earthworms was observed during the fourteen days longexposure. When the earthworms from the above test became a part of the diet of commonvoles in the following experiment, no mortality of consumers was observed too. However,electrochemical analysis revealed higher levels of bromadiolone in tissues fromearthworms as well as common voles compared to control animals. There were determinedcomparable levels of bromadiolone in the liver tissue of common voles after primary(2.34±0.10 μg/g) and secondary (2.20±0.53 μg/g) intoxication. Therefore, the risk ofsecondary intoxication of small mammalian species feeding on bromadiolone-containing earthworms is the same as of primary intoxication through baited granules. Bromadiolone bio-accumulation in the food chain was monitored using the newly developed analytical procedure based on the use of a liquid chromatography coupled with electrochemical detector (HPLC-ED). The HPLC-ED method allowed to determine the levels of bromadiolone in biological samples and is therefore suitable for examining the environmental hazards of this substance. Full article
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246 KiB  
Article
An Investigation of Glutathione-Platinum(II) Interactions by Means of the Flow Injection Analysis Using Glassy Carbon Electrode
by Ondrej Zitka, Dalibor Huska, Sona Krizkova, Vojtech Adam, Grace J. Chavis, Libuse Trnkova, Ales Horna, Jaromir Hubalek and Rene Kizek
Sensors 2007, 7(7), 1256-1270; https://doi.org/10.3390/s7071256 - 20 Jul 2007
Cited by 28 | Viewed by 12483
Abstract
Despite very intensive research in the synthesising of new cytostatics, cisplatin isstill one of the most commonly used anticancer drugs. Therefore, an investigation ofinteractions of cisplatin with different biologically important amino acids, peptides andproteins is very topical. In the present paper, we utilized [...] Read more.
Despite very intensive research in the synthesising of new cytostatics, cisplatin isstill one of the most commonly used anticancer drugs. Therefore, an investigation ofinteractions of cisplatin with different biologically important amino acids, peptides andproteins is very topical. In the present paper, we utilized flow injection analysis coupledwith electrochemical detection to study and characterize the behaviour of various forms ofglutathione (reduced glutathione – GSH, oxidized glutathione – GSSG and S-nitrosoglutathione – GSNO). The optimized conditions were as follows: mobile phase consistedof acetate buffer (pH 3) with a flow rate of 1 mL min-1. Based on results obtained we chose850 mV as the optimal potential for detection of GSH and 1,100 mV as the optimalpotential for detection of GSSG and GSNO. The detection limits of GSH, GSSG andGSNO were 100 pg mL-1, 50 ng mL-1 and 300 pg mL-1, respectively. Further, the optimized technique was used for investigation of interactions between cisplatin and GSH. We were able to observe the interaction between GSH and cisplatin via decrease in the signal corresponding to glutathione. Moreover, we evaluated the formation of the complex by spectrometry. The spectrometric results obtained were in good agreement with electrochemical ones. Full article
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379 KiB  
Article
Spectrometric and Voltammetric Analysis of Urease – Nickel Nanoelectrode as an Electrochemical Sensor
by Jaromir Hubalek, Jan Hradecky, Vojtech Adam, Olga Krystofova, Dalibor Huska, Michal Masarik, Libuse Trnkova, Ales Horna, Katerina Klosova, Martin Adamek, Josef Zehnalek and Rene Kizek
Sensors 2007, 7(7), 1238-1255; https://doi.org/10.3390/s7071238 - 16 Jul 2007
Cited by 52 | Viewed by 15257
Abstract
Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of [...] Read more.
Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of the methods utilized for detection ofurease are based on analysis of its enzyme activity – the hydrolysis of urea. The aim of thiswork was to detect urease indirectly by spectrometric method and directly by voltammetricmethods. As spectrometric method we used is called indophenol assay. The sensitivity ofdetection itself is not sufficient to analyse the samples without pre-concentration steps.Therefore we utilized adsorptive transfer stripping technique coupled with differential pulse voltammetry to detect urease. The influence of accumulation time, pH of supporting electrolyte and concentration of urease on the enzyme peak height was investigated. Under the optimized experimental conditions (0.2 M acetate buffer pH 4.6 and accumulation time of 120 s) the detection limit of urease evaluated as 3 S/N was 200 ng/ml. The activity of urease enzyme depends on the presence of nickel. Thus the influence of nickel(II) ions on electrochemical response of the enzyme was studied. Based on the results obtained the interaction of nickel(II) ions and urease can be determined using electrochemical methods. Therefore we prepared Ni nanoelectrodes to measure urease. The Ni nanoelectrodes was analysed after the template dissolution by scanning electron microscopy. The results shown vertically aligned Ni nanopillars almost covered the electrode surface, whereas the defect places are minor and insignificant in comparison with total electrode surface. We were able to not only detect urease itself but also to distinguish its native and denatured form. Full article
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2900 KiB  
Article
Proposal for an Ultrasonic Tool to Monitor the Osseointegration of Dental Implants
by Marina Storani De Almeida, Carlos Dias Maciel and José Carlos Pereira
Sensors 2007, 7(7), 1224-1237; https://doi.org/10.3390/s7071224 - 16 Jul 2007
Cited by 45 | Viewed by 13315
Abstract
The longevity of dental implants depends on osseointegration, which providesload-bearing capacity without putting the prosthesis at risk from micromotions at theimplant-bone interface. This research involved an analysis of the viability of an ultrasonicevaluation tool to quantify osseointegration. Ultrasonic transmission is directly dependenton the [...] Read more.
The longevity of dental implants depends on osseointegration, which providesload-bearing capacity without putting the prosthesis at risk from micromotions at theimplant-bone interface. This research involved an analysis of the viability of an ultrasonicevaluation tool to quantify osseointegration. Ultrasonic transmission is directly dependenton the difference between the acoustic impedance of materials in intimate contact witheach other. The closer their acoustic impedances the more intense their transmission.Therefore, an analysis of the ultrasonic echoes would presumably allow for a quantitativeevaluation of the bone tissue that has grown into the pores of the implant. In addition, theliterature reports that bone fracture healing can be accelerated by the application of acontrolled low-amplitude mechanical stimulus on the site of the lesion. In fact, acousticpressure waves of low-intensity pulsed ultrasound are reportedly a secure technique forpromoting mechanical stimulus without impairing the healing process. Many experimentaland clinical trials have confirmed that daily transcutaneous ultrasound applications on theinjured site are beneficial to the enhancement of fractured bone. This proposal aims tobring together the characteristics of ultrasound propagation and the positive effect ofultrasound on bone growth into a single tool that quantitatively monitors the evolution ofthe osseointegration process. The viability of a device with these features was investigatedthrough simulations and experimentally. The initial simulations were conducted to explorethe influence of waveguide shapes on the tool’s sensitivity to changes in the implantsupporting media. The waveguides were designed in two parts, one consisting of a screw-shaped part to attach to the implant and the other a conical or step-shaped part to which the ultrasonic source was fixed in the first simulations. The step-shaped waveguide proved to be the more sensitive; intermediate stages of the osseointegration process were simulated and experiments were conducted with the step-shaped aluminum waveguide attached to a cylindrical aluminum nut embedded at different depths, so that the results obtained were only due to lateral attachment of the parts. These devices indicated that the transmission of ultrasound through the lateral surface of the implant by dilatational waves could render this tool suitable for monitoring the osseointegration of dental implants. Full article
(This article belongs to the Special Issue Physiological Sensing)
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244 KiB  
Communication
Surface Plasmon Spectroscopic Detection of Saxitoxin
by Hongxia Chen, Youn Sook Kim, Sam-Rok Keum, Sung-Hoon Kim, Heung-Jin Choi, Jaebeom Lee, Won Gun An and Kwangnak Koh
Sensors 2007, 7(7), 1216-1223; https://doi.org/10.3390/s7071216 - 16 Jul 2007
Cited by 27 | Viewed by 10629
Abstract
For the surface-optoelectronic study of Saxitoxin sensing, we fabricated self-assembled calix[4]arene derivative monolayers as the recognition-functional interfaces ona gold surface. An interaction study between Saxitoxin and calix[4]arene derivativemonolayers were performed using surface plasmon resonance (SPR) spectroscopy. Amongthree calix[4]arene derivatives, calix[4]arene crown ether SAM [...] Read more.
For the surface-optoelectronic study of Saxitoxin sensing, we fabricated self-assembled calix[4]arene derivative monolayers as the recognition-functional interfaces ona gold surface. An interaction study between Saxitoxin and calix[4]arene derivativemonolayers were performed using surface plasmon resonance (SPR) spectroscopy. Amongthree calix[4]arene derivatives, calix[4]arene crown ether SAM showed the highestsensitivity to Saxitoxin. The detection limit of this system is three orders of magnitudelower than that of the mouse bioassay which is the current benchmark for Saxitoxindetection. Full article
(This article belongs to the Special Issue Optical Biosensors)
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687 KiB  
Article
Cluster-based Dynamic Energy Management for Collaborative Target Tracking in Wireless Sensor Networks
by Xue Wang, Jun-Jie Ma, Sheng Wang and Dao-Wei Bi
Sensors 2007, 7(7), 1193-1215; https://doi.org/10.3390/s7071193 - 13 Jul 2007
Cited by 50 | Viewed by 12482
Abstract
A primary criterion of wireless sensor network is energy efficiency. Focused onthe energy problem of target tracking in wireless sensor networks, this paper proposes acluster-based dynamic energy management mechanism. Target tracking problem isformulated by the multi-sensor detection model as well as energy consumption [...] Read more.
A primary criterion of wireless sensor network is energy efficiency. Focused onthe energy problem of target tracking in wireless sensor networks, this paper proposes acluster-based dynamic energy management mechanism. Target tracking problem isformulated by the multi-sensor detection model as well as energy consumption model. Adistributed adaptive clustering approach is investigated to form a reasonable routingframework which has uniform cluster head distribution. Dijkstra’s algorithm is utilized toobtain optimal intra-cluster routing. Target position is predicted by particle filter. Thepredicted target position is adopted to estimate the idle interval of sensor nodes. Hence,dynamic awakening approach is exploited to prolong sleep time of sensor nodes so that theoperation energy consumption of wireless sensor network can be reduced. The sensornodes around the target wake up on time and act as sensing candidates. With the candidatesensor nodes and predicted target position, the optimal sensor node selection is considered.Binary particle swarm optimization is proposed to minimize the total energy consumptionduring collaborative sensing and data reporting. Experimental results verify that theproposed clustering approach establishes a low-energy communication structure while theenergy efficiency of wireless sensor networks is enhanced by cluster-based dynamic energymanagement. Full article
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235 KiB  
Article
Flow-Injection Amperometric Determination of Tacrine based on Ion Transfer across a Water–Plasticized Polymeric Membrane Interface
by Joaquin A. Ortuño and C. Rueda
Sensors 2007, 7(7), 1185-1192; https://doi.org/10.3390/s7071185 - 11 Jul 2007
Cited by 5 | Viewed by 7712
Abstract
A flow-injection pulse amperometric method for determining tacrine, based onion transfer across a plasticized poly(vinyl chloride) (PVC) membrane, was developed. Afour-electrode potentiostat with ohmic drop compensation was used, while a flow-throughcell incorporated the four electrodes and the membrane, which containedtetrabutylammonium tetraphenylborate. The influence [...] Read more.
A flow-injection pulse amperometric method for determining tacrine, based onion transfer across a plasticized poly(vinyl chloride) (PVC) membrane, was developed. Afour-electrode potentiostat with ohmic drop compensation was used, while a flow-throughcell incorporated the four electrodes and the membrane, which containedtetrabutylammonium tetraphenylborate. The influence of the applied potential and of theflow-injection variables on the determination of tacrine was studied. In the selectedconditions, a linear relationship between peak height and tacrine concentration was foundup to 4x10-5M tacrine. The detection limit was 1x10-7M. Good repeatability was obtained.Some common ions and pharmaceutical excipients did not interfere. Full article
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515 KiB  
Article
VLF/LF Radio Sounding of Ionospheric Perturbations Associated with Earthquakes
by Masashi Hayakawa
Sensors 2007, 7(7), 1141-1158; https://doi.org/10.3390/s7071141 - 10 Jul 2007
Cited by 124 | Viewed by 14703
Abstract
It is recently recognized that the ionosphere is very sensitive to seismic effects,and the detection of ionospheric perturbations associated with earthquakes, seems to bevery promising for short-term earthquake prediction. We have proposed a possible use ofVLF/LF (very low frequency (3-30 kHz) /low frequency [...] Read more.
It is recently recognized that the ionosphere is very sensitive to seismic effects,and the detection of ionospheric perturbations associated with earthquakes, seems to bevery promising for short-term earthquake prediction. We have proposed a possible use ofVLF/LF (very low frequency (3-30 kHz) /low frequency (30-300 kHz)) radio sounding ofthe seismo-ionospheric perturbations. A brief history of the use of subionospheric VLF/LFpropagation for the short-term earthquake prediction is given, followed by a significantfinding of ionospheric perturbation for the Kobe earthquake in 1995. After showingprevious VLF/LF results, we present the latest VLF/LF findings; One is the statisticalcorrelation of the ionospheric perturbation with earthquakes and the second is a case studyfor the Sumatra earthquake in December, 2004, indicating the spatical scale and dynamicsof ionospheric perturbation for this earthquake. Full article
(This article belongs to the Special Issue Sensors for Disaster and Emergency Management Decision Making)
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944 KiB  
Article
Indium Tin Oxide-Polyaniline Biosensor: Fabrication and Characterization
by Zarini Muhammad Tahir, Evangelyn C. Alocilja and Daniel L. Grooms
Sensors 2007, 7(7), 1123-1140; https://doi.org/10.3390/s7071123 - 09 Jul 2007
Cited by 24 | Viewed by 9472
Abstract
In this study, a novel indium tin oxide (ITO)-polyaniline (Pani) biosensor wasdesigned, fabricated, and characterized. Initial testing was conducted for the detection ofbovine viral diarrhea virus (BVDV). The biosensor design was based upon the specific natureof antibodies to capture the target virus, and [...] Read more.
In this study, a novel indium tin oxide (ITO)-polyaniline (Pani) biosensor wasdesigned, fabricated, and characterized. Initial testing was conducted for the detection ofbovine viral diarrhea virus (BVDV). The biosensor design was based upon the specific natureof antibodies to capture the target virus, and the conductive properties of self-doped Pani totranslate the antibody-antigen binding into a quantifying signal. The first part of the study wasto assess the feasibility of the self-doped Pani to be incorporated into the biosensor design byevaluating its several parameters, such as conductivity, physical structure, thermogravimetricproperties, and antibody-binding properties. The second part of the paper highlights thefabrication of the ITO-Pani biosensor to detect the presence of bovine viral diarrhea virus(BVDV) in pure culture. Although only BVDV culture was tested in this study, the biosensoris versatile for the detection of other pathogen of interest by changing the specificity of theantibodies. Full article
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779 KiB  
Article
Monitoring of ULF (Ultra-Low-Frequency) Geomagnetic Variations Associated with Earthquakes
by Masashi Hayakawa, Katsumi Hattori and Kenji Ohta
Sensors 2007, 7(7), 1108-1122; https://doi.org/10.3390/s7071108 - 04 Jul 2007
Cited by 122 | Viewed by 14916
Abstract
ULF (ultra-low-frequency) electromagnetic emission is recently recognized as one of the most promising candidates for short-term earthquake prediction. This paper reviews previous convincing evidence on the presence of ULF emissions before a few large earthquakes. Then, we present our network of ULF monitoring [...] Read more.
ULF (ultra-low-frequency) electromagnetic emission is recently recognized as one of the most promising candidates for short-term earthquake prediction. This paper reviews previous convincing evidence on the presence of ULF emissions before a few large earthquakes. Then, we present our network of ULF monitoring in the Tokyo area by describing our ULF magnetic sensors and we finally present a few, latest results on seismogenic electromagnetic emissions for recent large earthquakes with the use of sophisticated signal processings. Full article
(This article belongs to the Special Issue Sensors for Disaster and Emergency Management Decision Making)
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1082 KiB  
Article
Comparative Study of Protein Immobilization Properties on Calixarene Monolayers
by Hongxia Chen, Minsu Lee, Sungwook Choi, Jae-Ho Kim, Heung-Jin Choi, Sung-Hoon Kim, Jeabeom Lee and Kwangnak Koh
Sensors 2007, 7(7), 1091-1107; https://doi.org/10.3390/s7071091 - 29 Jun 2007
Cited by 28 | Viewed by 10152
Abstract
Three calix[4]arene (Cal-4) derivatives of which contain ethylester (1),carboxylic acid (2), and crownether (3) at the lower rim with a common reactive thiol at theupper rim were synthesized and constructed to self-assembled monolayers (SAMs) on Aufilms. After spectroscopic characterization of monolayers, the interaction [...] Read more.
Three calix[4]arene (Cal-4) derivatives of which contain ethylester (1),carboxylic acid (2), and crownether (3) at the lower rim with a common reactive thiol at theupper rim were synthesized and constructed to self-assembled monolayers (SAMs) on Aufilms. After spectroscopic characterization of monolayers, the interaction between Cal-4and surface confined bovine serum albumin (BSA) in the SAMs was analyzed by surfaceplasmon resonance (SPR). The estimated surface concentration of BSA on the Cal-4 SAMwith crownether group was the highest among the three Cal-4 derivatives. Anti-hIgG andhIgG pair was employed for the investigation of protein-protein interaction. Molecularinteraction between anti-hIgG and hIgG can be detected in a concentration range of 10pg/mL to 200 pg/mL on the Cal-4 derivative 3 SAM modified SPR chip. Full article
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757 KiB  
Article
Methods for Solving Gas Damping Problems in Perforated Microstructures Using a 2D Finite-Element Solver
by Timo Veijola and Peter Raback
Sensors 2007, 7(7), 1069-1090; https://doi.org/10.3390/s7071069 - 28 Jun 2007
Cited by 38 | Viewed by 11567
Abstract
We present a straightforward method to solve gas damping problems for perfo-rated structures in two dimensions (2D) utilising a Perforation Profile Reynolds (PPR) solver.The PPR equation is an extended Reynolds equation that includes additional terms modellingthe leakage flow through the perforations, and variable [...] Read more.
We present a straightforward method to solve gas damping problems for perfo-rated structures in two dimensions (2D) utilising a Perforation Profile Reynolds (PPR) solver.The PPR equation is an extended Reynolds equation that includes additional terms modellingthe leakage flow through the perforations, and variable diffusivity and compressibility pro-files. The solution method consists of two phases: 1) determination of the specific admittanceprofile and relative diffusivity (and relative compressibility) profiles due to the perforation,and 2) solution of the PPR equation with a FEM solver in 2D. Rarefied gas corrections inthe slip-flow region are also included. Analytic profiles for circular and square holes withslip conditions are presented in the paper. To verify the method, square perforated damperswith 16 – 64 holes were simulated with a three-dimensional (3D) Navier-Stokes solver, a ho-mogenised extended Reynolds solver, and a 2D PPR solver. Cases for both translational (innormal to the surfaces) and torsional motion were simulated. The presented method extendsthe region of accurate simulation of perforated structures to cases where the homogenisationmethod is inaccurate and the full 3D Navier-Stokes simulation is too time-consuming. Full article
(This article belongs to the Special Issue Modeling, Testing and Reliability Issues in MEMS Engineering)
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661 KiB  
Article
Development of a Fully Automated, GPS Based Monitoring System for Disaster Prevention and Emergency Preparedness: PPMS+RT
by Jason Bond, Don Kim, Adam Chrzanowski and Anna Szostak-Chrzanowski
Sensors 2007, 7(7), 1028-1046; https://doi.org/10.3390/s7071028 - 28 Jun 2007
Cited by 14 | Viewed by 12363
Abstract
The increasing number of structural collapses, slope failures and other naturaldisasters has lead to a demand for new sensors, sensor integration techniques and dataprocessing strategies for deformation monitoring systems. In order to meet extraordinaryaccuracy requirements for displacement detection in recent deformation monitoringprojects, research [...] Read more.
The increasing number of structural collapses, slope failures and other naturaldisasters has lead to a demand for new sensors, sensor integration techniques and dataprocessing strategies for deformation monitoring systems. In order to meet extraordinaryaccuracy requirements for displacement detection in recent deformation monitoringprojects, research has been devoted to integrating Global Positioning System (GPS) as amonitoring sensor. Although GPS has been used for monitoring purposes worldwide,certain environments pose challenges where conventional processing techniques cannotprovide the required accuracy with sufficient update frequency. Described is thedevelopment of a fully automated, continuous, real-time monitoring system that employsGPS sensors and pseudolite technology to meet these requirements in such environments.Ethernet and/or serial port communication techniques are used to transfer data betweenGPS receivers at target points and a central processing computer. The data can beprocessed locally or remotely based upon client needs. A test was conducted that illustrateda 10 mm displacement was remotely detected at a target point using the designed system.This information could then be used to signal an alarm if conditions are deemed to beunsafe. Full article
(This article belongs to the Special Issue Sensors for Disaster and Emergency Management Decision Making)
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551 KiB  
Article
Motion Estimation Using the Single-row Superposition-type Planar Compound-like Eye
by Chi-Cheng Cheng and Gwo-Long Lin
Sensors 2007, 7(7), 1047-1068; https://doi.org/10.3390/s7071047 - 27 Jun 2007
Cited by 2 | Viewed by 8988
Abstract
How can the compound eye of insects capture the prey so accurately andquickly? This interesting issue is explored from the perspective of computer vision insteadof from the viewpoint of biology. The focus is on performance evaluation of noiseimmunity for motion recovery using the [...] Read more.
How can the compound eye of insects capture the prey so accurately andquickly? This interesting issue is explored from the perspective of computer vision insteadof from the viewpoint of biology. The focus is on performance evaluation of noiseimmunity for motion recovery using the single-row superposition-type planar compound-like eye (SPCE). The SPCE owns a special symmetrical framework with tremendousamount of ommatidia inspired by compound eye of insects. The noise simulates possibleambiguity of image patterns caused by either environmental uncertainty or low resolutionof CCD devices. Results of extensive simulations indicate that this special visualconfiguration provides excellent motion estimation performance regardless of themagnitude of the noise. Even when the noise interference is serious, the SPCE is able todramatically reduce errors of motion recovery of the ego-translation without any type offilters. In other words, symmetrical, regular, and multiple vision sensing devices of thecompound-like eye have statistical averaging advantage to suppress possible noises. Thisdiscovery lays the basic foundation in terms of engineering approaches for the secret of thecompound eye of insects. Full article
(This article belongs to the Special Issue Intelligent Sensors)
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