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Sample records for coulometric array detection

  1. Biomarker differences between cadaveric grafts used in human orthotopic liver transplantation as identified by coulometric electrochemical array detection (CEAD) metabolomics.

    Science.gov (United States)

    Perera, M Thamara P R; Higdon, Roger; Richards, Douglas A; Silva, Michael A; Murphy, Nick; Kolker, Eugene; Mirza, Darius F

    2014-12-01

    Metabolomics in systems biology research unravels intracellular metabolic changes by high throughput methods, but such studies focusing on liver transplantation (LT) are limited. Microdialysate samples of liver grafts from donors after circulatory death (DCD; n=13) and brain death (DBD; n=27) during cold storage and post-reperfusion phase were analyzed through coulometric electrochemical array detection (CEAD) for identification of key metabolomics changes. Metabolite peak differences between the graft types at cold phase, post-reperfusion trends, and in failed allografts, were identified against reference chromatograms. In the cold phase, xanthine, uric acid, and kynurenine were overexpressed in DCD by 3-fold, and 3-nitrotyrosine (3-NT) and 4-hydroxy-3-methoxymandelic acid (HMMA) in DBD by 2-fold (pidentification of overexpression of kynurenine in DCD grafts and in failed allografts is unique. Further studies should examine kynurenine as a potential biomarker predicting graft function, its causation, and actions on subsequent clinical outcomes.

  2. Determination of secoisolariciresinol, lariciresinol and isolariciresinol in plant foods by high performance liquid chromatography coupled with coulometric electrode array detection.

    Science.gov (United States)

    Schwartz, Heidi; Sontag, Gerhard

    2006-07-11

    The paper describes a method for the determination of selected lignans in plant foods. First, samples were submitted to methanolysis resulting in cleavage of ester bonds between lignan glycosides and organic acids. Glycosidic linkages were then broken by enzymatic hydrolysis using cellulase. The released aglycones were separated isocratically (acetonitrile/10 mM sodium acetate buffer, pH 4.8, 225:775, v:v) by reversed phase high performance liquid chromatography (RP-HPLC) and the compounds were detected coulometrically at four electrodes set on potentials between +260 and +330 mV against palladium reference electrodes. The selectivity and sensitivity of the method allowed quantitation of the lignans secoisolariciresinol, lariciresinol and isolariciresinol in various foodstuffs down to the upper ppb-range with recoveries between 44.7 and 97.0%. Unidentified peaks displaying similar current-voltage curves (CVCs) as the investigated lignans indicated the presence of further possible lignan representatives. In addition, investigation of various foodstuffs involving enzymatic hydrolysis with and without preceding methanolysis showed that the degree of esterification of lignans in plant foods is species dependent.

  3. Simultaneous fingerprint, quantitative analysis and anti-oxidative based screening of components in Rhizoma Smilacis Glabrae using liquid chromatography coupled with Charged Aerosol and Coulometric array Detection.

    Science.gov (United States)

    Yang, Guang; Zhao, Xin; Wen, Jun; Zhou, Tingting; Fan, Guorong

    2017-04-01

    An analytical approach including fingerprint, quantitative analysis and rapid screening of anti-oxidative components was established and successfully applied for the comprehensive quality control of Rhizoma Smilacis Glabrae (RSG), a well-known Traditional Chinese Medicine with the homology of medicine and food. Thirteen components were tentatively identified based on their retention behavior, UV absorption and MS fragmentation patterns. Chemometric analysis based on coulmetric array data was performed to evaluate the similarity and variation between fifteen batches. Eight discriminating components were quantified using single-compound calibration. The unit responses of those components in coulmetric array detection were calculated and compared with those of several compounds reported to possess antioxidant activity, and four of them were tentatively identified as main contributors to the total anti-oxidative activity. The main advantage of the proposed approach was that it realized simultaneous fingerprint, quantitative analysis and screening of anti-oxidative components, providing comprehensive information for quality assessment of RSG.

  4. Coulometric trace determination of water by using Karl Fischer reagent and potentiometric end-point detection.

    Science.gov (United States)

    Cedergren, A

    1974-06-01

    A new approach to the determination of water via the Karl Fischer reaction is described. Iodine is coulometrically generated and the end-point corresponding to a slight excess of iodine, is detected potentiometrically with a non-polarized platinum electrode. Samples of 1-500 mul containing 0.05-200 mug of water were analysed with a standard deviation of 0.015 mug in the range 0.05-20 mug of H(2)O. A specially constructed electrolysis cell was used in combination with an LKB 16300 Coulometric Analyzer and the time for a complete analysis was 1-4 min, depending on sample size. The reagent composition has been optimized in order to enhance the rate of the main reaction and to minimize the extent of side-reactions. Decreasing the temperature reduced the extent of side-reactions. The displacement of end-point potential on dilution was studied and a correction is discussed.

  5. Coulometric Titration of Ethylenediaminetetraacetate (EDTA) with Spectrophotometric Endpoint Detection: An Experiment for the Instrumental Analysis Laboratory

    Science.gov (United States)

    Williams, Kathryn R.; Young, Vaneica Y.; Killian, Benjamin J.

    2011-01-01

    Ethylenediaminetetraacetate (EDTA) is commonly used as an anticoagulant in blood-collection procedures. In this experiment for the instrumental analysis laboratory, students determine the quantity of EDTA in commercial collection tubes by coulometric titration with electrolytically generated Cu[superscript 2+]. The endpoint is detected…

  6. Array for detecting microbes

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Gary L.; DeSantis, Todd D.

    2014-07-08

    The present embodiments relate to an array system for detecting and identifying biomolecules and organisms. More specifically, the present embodiments relate to an array system comprising a microarray configured to simultaneously detect a plurality of organisms in a sample at a high confidence level.

  7. Determination of oxytocin in biological samples by isocratic high-performance liquid chromatography with coulometric detection using C18 solid-phase extraction and polyclonal antibody-based immunoaffinity column purification.

    Science.gov (United States)

    Kukucka, M A; Misra, H P

    1994-03-04

    A specific high-performance liquid chromatographic (HPLC) method is described for the reliable quantitation of oxytocin using culture media supernatants. The procedure employs solid-phase extraction, antibody-based immunoaffinity purification and isocratic HPLC with dual channel coulometric detection (ED). The lower limit of detection for this cyclic nonapeptide was 40 pg (40 fmol). Due to its relative simplicity, specificity and precision, the HPLC-ED of oxytocin is an accurate and attractive alternative to many existing quantitative methods.

  8. Simultaneous determination of five common additives in insulating mineral oils by high-performance liquid chromatography with ultraviolet and coulometric detection.

    Science.gov (United States)

    Bruzzoniti, Maria Concetta; Sarzanini, Corrado; Rivoira, Luca; Tumiatti, Vander; Maina, Riccardo

    2016-08-01

    Dielectric mineral oils are used to impregnate power transformers and large electrical apparatus, acting as both liquid insulation and heat dissipation media. Antioxidants and passivators are frequently added to mineral oils to enhance oxidation stability and reduce the electrostatic charging tendency, respectively. Since existing standard test methods only allow analysis of individual additives, new approaches are needed for the detection of mixtures. For the first time we investigate and discuss the performance of analytical methods, which require or do not require extraction as sample pretreatment, for the simultaneous reversed-phase high-performance liquid chromatography determination of passivators (benzotriazole, Irgamet(®) 39) and antioxidants (N-phenyl-1-naphtylamine, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol), chosen for their presence in marketed oils. Quick easy, cheap, effective, rugged and safe and solid phase extractions were evaluated as sample pretreatments. Direct sample-injection was also studied. Ultraviolet spectrophotometry and direct-current coulometry detection were explored. As less prone to additive concentrations variability, the direct-injection high-performance liquid chromatography with ultraviolet and coulometric detection method was validated through comparison with Standard Method IEC 60666 and through an ASTM interlaboratory proficiency test. Obtained detection limits are (mg kg(-1) ): benzotriazole (2.8), Irgamet(®) 39 (13.8), N-phenyl-1-naphtylamine (11.9), 2,6-di-tert-butylphenol (13.1), 2,6-di-tert-butyl-p-cresol (10.2). Simultaneous determination of selected additives was possible both in unused and used oils, with good precision and accuracy.

  9. Determination of vanillylmandelic acid, vanillactic acid, and homovanillic acid in dried urine on filter-paper discs by high-performance liquid chromatography with coulometric electrochemical detection for neuroblastoma screening.

    Science.gov (United States)

    Kinoshita, Y; Yamada, S; Haraguchi, K; Takayanagi, T; Mori, Y; Takahashi, T; Haruki, E

    1988-11-01

    We report a method for determination of vanillylmandelic acid, vanillactic acid, and homovanillic acid by high-performance liquid chromatography (HPLC), with coulometric electrochemical detection, for mass screening of neuroblastoma. Urine samples were collected on filter paper, dried, and then pretreated. The chromatographic procedure is reliable and fast, allowing for a large sample throughput for routine screening. Intricate extraction procedures and centrifugal separation are unnecessary. Screening for neuroblastoma by HPLC is rapidly gaining acceptance in Japan, and our method is being used at many screening centers. Of 26,571 infants screened in one year in Yokohama City, our method detected five with neuroblastoma.

  10. Delamination Detection Using Guided Wave Phased Arrays

    Science.gov (United States)

    Tian, Zhenhua; Yu, Lingyu; Leckey, Cara

    2016-01-01

    This paper presents a method for detecting multiple delaminations in composite laminates using non-contact phased arrays. The phased arrays are implemented with a non-contact scanning laser Doppler vibrometer (SLDV). The array imaging algorithm is performed in the frequency domain where both the guided wave dispersion effect and direction dependent wave properties are considered. By using the non-contact SLDV array with a frequency domain imaging algorithm, an intensity image of the composite plate can be generated for delamination detection. For the proof of concept, a laboratory test is performed using a non-contact phased array to detect two delaminations (created through quasi-static impact test) at different locations in a composite plate. Using the non-contact phased array and frequency domain imaging, the two impact-induced delaminations are successfully detected. This study shows that the non-contact phased array method is a potentially effective method for rapid delamination inspection in large composite structures.

  11. Array Biosensor for Toxin Detection: Continued Advances

    Directory of Open Access Journals (Sweden)

    Chris Rowe Taitt

    2008-12-01

    Full Text Available The following review focuses on progress made in the last five years with the NRL Array Biosensor, a portable instrument for rapid and simultaneous detection of multiple targets. Since 2003, the Array Biosensor has been automated and miniaturized for operation at the point-of-use. The Array Biosensor has also been used to demonstrate (1 quantitative immunoassays against an expanded number of toxins and toxin indicators in food and clinical fluids, and (2 the efficacy of semi-selective molecules as alternative recognition moieties. Blind trials, with unknown samples in a variety of matrices, have demonstrated the versatility, sensitivity, and reliability of the automated system.

  12. DETECTION OF BACTERIAL TOXINS WITH MONOSACCHARIDE ARRAYS

    Science.gov (United States)

    Ngundi, Miriam M.; Taitt, Chris R.; McMurry, Scott A.; Kahne, Daniel; Ligler, Frances S.

    2006-01-01

    A large number of bacterial toxins, viruses and bacteria target carbohydrate derivatives on the cell surface to attach to and gain entry into the cell. We report here the use of a monosaccharide-based array to detect protein toxins. The array-based technique provides the capability to perform simultaneous multianalyte analyses. Arrays of N-acetyl galactosamine (GalNAc) and N-acetylneuraminic acid (Neu5Ac) derivatives were immobilized on the surface of a planar waveguide and were used as receptors for protein toxins. These arrays were probed with fluorescently labeled bacterial cells and protein toxins. While Salmonella typhimurium, Listeria monocytogenes, Escherichia coli and staphylococcal enterotoxin B (SEB) did not bind to either of the monosaccharides, both cholera toxin and tetanus toxin bound to GalNAc and Neu5Ac. The results show that the binding of the toxins to the carbohydrates is density dependent and semi-selective. Both toxins were detectable at 100 ng/ml. PMID:15946840

  13. 库仑阵列电化学测定尿儿茶酚胺代谢物方法的建立及其在神经母细胞瘤诊断中的应用%Determination of urinary catecholamines metabolites by coulometric electrode array system (CoulArray) in diagnosis of neuroblastoma

    Institute of Scientific and Technical Information of China (English)

    常会波; 保睿; 叶辉; 李龙; 张晓伦; 邹继珍; 刘卓; 吴建新

    2010-01-01

    目的 建立以反相液相色谱-库仑阵列电化学联用紫外检测法同时测定随机尿液中儿茶酚胺代谢产物方法,并应用于0~10岁儿童正常值范围的确立及神经母细胞瘤的诊断.方法 反相液相色谱梯度洗脱法分离样品,库仑阵列电化学定量检测VMA和HVA的浓度,紫外检测器检测Cr的浓度.以VMA/Cr和HVA/Cr表示尿儿茶酚胺代谢物的含量.对该法进行系统性评价后应用于120例健康儿童和15例神经母细胞瘤患儿随机尿样的测定中.结果 VMA、HVA和Cr的日内变异系数和日问变异系数均小于5%,线性相关系数均大于0.9990.回收率均大于95%.健康儿童VMA/Cr(2.99±1.77)μg/mg和HVA/Cr(3.40±1.50)μg/mg与年龄有显著相关性(P<0.001),0~2岁组[VMA/Cr(4.04±1.24)μg/mg,HVA/Cr(4.87±1.81)μg/mg]与其他年龄组[2~4岁:VMA/Cr(3.02±0.81)μg/mg,HVA/Cr(3.46±1.06)μg/mg;4~6岁:VMA/Cr(2.68±0.95)μg/mg,HVA/Cr(2.75±1.04)μg/mg;6~10岁:VMA/Cr(2.32±0.95)μg/mg,HVA/Cr(2.61±0.84)μg/mg]差异均有统计学意义(P<0.001).以低于(-x)+3s作为正常值,超过此范围诊断为神经母细胞瘤,对患儿诊断的符合率达93%.结论 本研究建立了同时快速准确检测随机尿样VMA、HVA和Cr的方法,并分年龄组建立了0~10岁儿童的正常值范围,为神经母细胞瘤的诊断和筛查提供了有效的参考指标和简单易行、准确灵敏的生化检验手段,也可用于与儿茶酚胺异常分泌相关的其他研究领域.%Objective To establish reverse phase liquid chromatographic(RPLC) with CoulArray(coulometric electrode array system) in assaying urinary catecholamines metabolites and establish normal reference ranges for neuroblastoma diagnosis. Methods Samples were processed by binary gradient reversed phase chromatography. Vanillylmandelic acid (VMA) and homovanillic acid(HVA)were assayed by CoulArray, and creatinine(Cr)was by UV detector. The contents of catecholamines metabolites were expressed as VMA

  14. The Giant Radio Array for Neutrino Detection

    Directory of Open Access Journals (Sweden)

    Martineau-Huynh Olivier

    2016-01-01

    Full Text Available High-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND project consists of an array of ∼ 105 radio antennas deployed over ∼ 200 000 km2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of τ leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 × 10−11E−2 GeV−1 cm−2 s−1 sr−1 above 3 × 1016 eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs.

  15. Rapid coulometric method for the Kjeldahl determination of nitrogen.

    Science.gov (United States)

    Boström, C A; Cedergren, A; Johansson, G; Pettersson, I

    1974-11-01

    A rapid coulometric method for the Kjeldahl determination of nitrogen is described. The samples are digested by means of the Tecator AB digestion system which permits forty samples to be digested at the same time. The digestion products are diluted to 75 ml and 1 ml is coulometrically titrated in 1-2 min: 20-30 determinations can be performed per hour. For substances containing nitrogen in the per cent range the relative standard deviations for eight different substances were 0.1-1%.

  16. The coulometric titration of acids and bases in dimethylsulfoxide media

    NARCIS (Netherlands)

    Bos, M.; IJpma, S.T.; Dahmen, E.A.M.F.

    1976-01-01

    The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current

  17. Graphene microelectrode arrays for neural activity detection.

    Science.gov (United States)

    Du, Xiaowei; Wu, Lei; Cheng, Ji; Huang, Shanluo; Cai, Qi; Jin, Qinghui; Zhao, Jianlong

    2015-09-01

    We demonstrate a method to fabricate graphene microelectrode arrays (MEAs) using a simple and inexpensive method to solve the problem of opaque electrode positions in traditional MEAs, while keeping good biocompatibility. To study the interface differences between graphene-electrolyte and gold-electrolyte, graphene and gold electrodes with a large area were fabricated. According to the simulation results of electrochemical impedances, the gold-electrolyte interface can be described as a classical double-layer structure, while the graphene-electrolyte interface can be explained by a modified double-layer theory. Furthermore, using graphene MEAs, we detected the neural activities of neurons dissociated from Wistar rats (embryonic day 18). The signal-to-noise ratio of the detected signal was 10.31 ± 1.2, which is comparable to those of MEAs made with other materials. The long-term stability of the MEAs is demonstrated by comparing differences in Bode diagrams taken before and after cell culturing.

  18. Oxidative coulometric trace determination of sulphur in hydrocarbons.

    Science.gov (United States)

    Cedergren, A

    1973-07-01

    A new combustion system for the oxidative coulometric determination of sulphur in liquid hydrocarbons is described. The conditions were selected so that the recovery as SO(2) was close to 100%. The relative standard deviation was < 1% for sulphur in the range 2-1000 mg/l., with thiophene in cyclohexane as a test substance. Thermodynamic data on the equilibrium between SO(2), O(2) and SO(3) were used to select the operating conditions. To increase the recovery of SO(2) the combustion gas mixture was diluted with an inert gas to lower the partial pressure of oxygen. A temperature of 1000 degrees in the equilibrium zone resulted in a recovery of 99%. The SO(2) was titrated with coulometrically generated iodine, the concentration of which was controlled by a Pt-redox electrode. The response of this electrode has been examined. A rather high concentration of I(-) was used to suppress iodine losses during the analysis. The time of analysis was 2-5 min, and sample sizes were 3-7 mul. An LKB 16300 Coulometric Analyzer governed the titration procedure.

  19. Detecting and correcting hard errors in a memory array

    Energy Technology Data Exchange (ETDEWEB)

    Kalamatianos, John; John, Johnsy Kanjirapallil; Gelinas, Robert; Sridharan, Vilas K.; Nevius, Phillip E.

    2015-11-19

    Hard errors in the memory array can be detected and corrected in real-time using reusable entries in an error status buffer. Data may be rewritten to a portion of a memory array and a register in response to a first error in data read from the portion of the memory array. The rewritten data may then be written from the register to an entry of an error status buffer in response to the rewritten data read from the register differing from the rewritten data read from the portion of the memory array.

  20. Graphene microelectrode arrays for neural activity detection

    OpenAIRE

    Du, Xiaowei; Wu,Lei; Cheng, Ji; Huang, Shanluo; Cai, Qi; Jin, Qinghui; Zhao, Jianlong

    2015-01-01

    We demonstrate a method to fabricate graphene microelectrode arrays (MEAs) using a simple and inexpensive method to solve the problem of opaque electrode positions in traditional MEAs, while keeping good biocompatibility. To study the interface differences between graphene–electrolyte and gold–electrolyte, graphene and gold electrodes with a large area were fabricated. According to the simulation results of electrochemical impedances, the gold–electrolyte interface can be described as a class...

  1. Carbon Nanotube Array for Infrared Detection

    Science.gov (United States)

    2011-09-28

    mechanical strength, and infrared absorption efficiency are also important. [7] In these regards, thin membranes of carbon nanotubes have much to offer...Kimball, J. Carlson, D. Ziegler , G. E. Fernandes, Z. Liu, J. H. Kim, and J. Xu, “Coupled, large-format gold nanowire arrays for nanorectenna energy...Phys. Lett. 95, 231113 (2009). 10. R. Osgood III, J.B. Carlson, B.R. Kimball, D.P. Ziegler , J.R. Welch, L.E. Belton, G. Fernandes, Z. Liu, J.M. Xu

  2. A functional gene array for detection of bacterial virulence elements.

    Directory of Open Access Journals (Sweden)

    Crystal Jaing

    Full Text Available Emerging known and unknown pathogens create profound threats to public health. Platforms for rapid detection and characterization of microbial agents are critically needed to prevent and respond to disease outbreaks. Available detection technologies cannot provide broad functional information about known or novel organisms. As a step toward developing such a system, we have produced and tested a series of high-density functional gene arrays to detect elements of virulence and antibiotic resistance mechanisms. Our first generation array targets genes from Escherichia coli strains K12 and CFT073, Enterococcus faecalis and Staphylococcus aureus. We determined optimal probe design parameters for gene family detection and discrimination. When tested with organisms at varying phylogenetic distances from the four target strains, the array detected orthologs for the majority of targeted gene families present in bacteria belonging to the same taxonomic family. In combination with whole-genome amplification, the array detects femtogram concentrations of purified DNA, either spiked in to an aerosol sample background, or in combinations from one or more of the four target organisms. This is the first report of a high density NimbleGen microarray system targeting microbial antibiotic resistance and virulence mechanisms. By targeting virulence gene families as well as genes unique to specific biothreat agents, these arrays will provide important data about the pathogenic potential and drug resistance profiles of unknown organisms in environmental samples.

  3. Signal processing for solar array monitoring, fault detection, and optimization

    CERN Document Server

    Braun, Henry; Spanias, Andreas

    2012-01-01

    Although the solar energy industry has experienced rapid growth recently, high-level management of photovoltaic (PV) arrays has remained an open problem. As sensing and monitoring technology continues to improve, there is an opportunity to deploy sensors in PV arrays in order to improve their management. In this book, we examine the potential role of sensing and monitoring technology in a PV context, focusing on the areas of fault detection, topology optimization, and performance evaluation/data visualization. First, several types of commonly occurring PV array faults are considered and detection algorithms are described. Next, the potential for dynamic optimization of an array's topology is discussed, with a focus on mitigation of fault conditions and optimization of power output under non-fault conditions. Finally, monitoring system design considerations such as type and accuracy of measurements, sampling rate, and communication protocols are considered. It is our hope that the benefits of monitoring presen...

  4. RFI Source Detection using Array Beamforming Technique

    OpenAIRE

    2015-01-01

    Accurate localization of microwave emitting sources is an important topic, in telecommunication and remote sensing. Especially, in order to increase the data quality of satellite microwave remote sensing, radio frequency interference (RFI) sources need to be accurately geolocated. This project offers the opportunity to learn and experience the method for high-performance detection and localization of RFI sources. Study of radio frequency interference definition and detection techniques. ...

  5. Detecting nanohertz gravitational waves with pulsar timing arrays

    CERN Document Server

    Zhu, Xing-Jiang; Hobbs, George; Manchester, Richard N; Shannon, Ryan M

    2015-01-01

    Complementary to ground-based laser interferometers, pulsar timing array experiments are being carried out to search for nanohertz gravitational waves. Using the world's most powerful radio telescopes, three major international collaborations have collected $\\sim$10-year high precision timing data for tens of millisecond pulsars. In this paper we give an overview on pulsar timing experiments, gravitational wave detection in the nanohertz regime, and recent results obtained by various timing array projects.

  6. WIMP detection and slow ion dynamics in carbon nanotube arrays

    OpenAIRE

    Cavoto, G.; Cirillo, E. N. M.; Cocina, F.; Ferretti, J.; Polosa, A. D.

    2016-01-01

    Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy lo...

  7. A functional gene array for detection of bacterial virulence elements

    Energy Technology Data Exchange (ETDEWEB)

    Jaing, C

    2007-11-01

    We report our development of the first of a series of microarrays designed to detect pathogens with known mechanisms of virulence and antibiotic resistance. By targeting virulence gene families as well as genes unique to specific biothreat agents, these arrays will provide important data about the pathogenic potential and drug resistance profiles of unknown organisms in environmental samples. To validate our approach, we developed a first generation array targeting genes from Escherichia coli strains K12 and CFT073, Enterococcus faecalis and Staphylococcus aureus. We determined optimal probe design parameters for microorganism detection and discrimination, measured the required target concentration, and assessed tolerance for mismatches between probe and target sequences. Mismatch tolerance is a priority for this application, due to DNA sequence variability among members of gene families. Arrays were created using the NimbleGen Maskless Array Synthesizer at Lawrence Livermore National Laboratory. Purified genomic DNA from combinations of one or more of the four target organisms, pure cultures of four related organisms, and environmental aerosol samples with spiked-in genomic DNA were hybridized to the arrays. Based on the success of this prototype, we plan to design further arrays in this series, with the goal of detecting all known virulence and antibiotic resistance gene families in a greatly expanded set of organisms.

  8. Detection of fast transients with radio interferometric arrays

    CERN Document Server

    Bhat, N D R; Cox, P J; Gupta, Y; Prasad, J; Roy, J; Bailes, M; Burke-Spolaor, S; Kudale, S S; van Straten, W

    2013-01-01

    Next-generation radio arrays, including the SKA and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT)presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis s...

  9. Gravitational wave detection and data analysis for pulsar timing arrays

    NARCIS (Netherlands)

    Haasteren, Rutger van

    2011-01-01

    Long-term precise timing of Galactic millisecond pulsars holds great promise for measuring long-period (months-to-years) astrophysical gravitational waves. In this work we develop a Bayesian data analysis method for projects called pulsar timing arrays; projects aimed to detect these gravitational w

  10. Comparison of Two Detection Combination Algorithms for Phased Array Radars

    Science.gov (United States)

    2015-07-01

    weapon guidance. It can also be used effectively for secure communications [1]. In an MFR, the radar surveillance plays a critical role to optimize the...horizon/surface search, detection confirmation, multi-target tracking and cued search. The simulated radar has an aperture of 1 m2. The antennas...Comparison of Two Detection Combination Algorithms for Phased Array Radars Zhen Ding and Peter Moo Wide Area Surveillance Radar Group Radar

  11. ARRAY PULSED EDDY CURRENT IMAGING SYSTEM USED TO DETECT CORROSION

    Institute of Scientific and Technical Information of China (English)

    Yang Binfeng; Luo Feilu; Cao Xiongheng; Xu Xiaojie

    2005-01-01

    A theory model is established to describe the voltage-current response function. The peak amplitude and the zero-crossing time of the transient signal is extracted as the imaging features, array pulsed eddy current (PEC) imaging is proposed to detect corrosion. The test results show that this system has the advantage of fast scanning speed, different imaging mode and quantitative detection, it has a broad application in the aviation nondestructive testing.

  12. CRF: detection of CRISPR arrays using random forest

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2017-04-01

    Full Text Available CRISPRs (clustered regularly interspaced short palindromic repeats are particular repeat sequences found in wide range of bacteria and archaea genomes. Several tools are available for detecting CRISPR arrays in the genomes of both domains. Here we developed a new web-based CRISPR detection tool named CRF (CRISPR Finder by Random Forest. Different from other CRISPR detection tools, a random forest classifier was used in CRF to filter out invalid CRISPR arrays from all putative candidates and accordingly enhanced detection accuracy. In CRF, particularly, triplet elements that combine both sequence content and structure information were extracted from CRISPR repeats for classifier training. The classifier achieved high accuracy and sensitivity. Moreover, CRF offers a highly interactive web interface for robust data visualization that is not available among other CRISPR detection tools. After detection, the query sequence, CRISPR array architecture, and the sequences and secondary structures of CRISPR repeats and spacers can be visualized for visual examination and validation. CRF is freely available at http://bioinfolab.miamioh.edu/crf/home.php.

  13. EMAT phased array: A feasibility study of surface crack detection.

    Science.gov (United States)

    Isla, J; Cegla, F

    2017-02-14

    Electromagnetic-acoustic transducers (EMATs) consist of a magnet and a coil. They are advantageous in some non-destructive evaluation (NDE) applications because no direct contact with the specimen is needed to send and receive ultrasonic waves. However, EMATs commonly require excitation peak powers greater than 1kW and therefore the driving electronics and the EMAT coils have to be bulky. This has hindered the development of EMAT phased arrays with characteristics similar to those of conventional piezoelectric phased arrays. Phased arrays are widely used in NDE because they offer superior defect characterization in comparison to single-element transducers. In this paper, we report a series of novel techniques and design elements that make it possible to construct an EMAT phased array that performs similarly to conventional piezoelectric arrays used in NDE. One of the key enabling features is the use of coded excitation to reduce the excitation peak power to less than 4.8W (24 Vpp and 200mA) so that racetrack coils with dimensions 3.2×18mm(2) can be employed. Moreover, these racetrack coils are laid out along their shortest dimension so that 1/3 of their area is overlapped. This helps to reduce the crosstalk between the coils, i.e., the array elements, to less than -15dB. We show that an 8-element EMAT phased array operating at a central frequency of 1MHz can be used to detect defects which have a width and a depth of 0.2 and 0.8mm respectively and are located on the surface opposite to the array.

  14. A selective metabolite array for the detection of phosphometabolites

    Energy Technology Data Exchange (ETDEWEB)

    Salim, Malinda; Fowler, Gregory J.S.; Wright, Phillip C. [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, S1 3JD Sheffield (United Kingdom); Vaidyanathan, Seetharaman, E-mail: s.vaidyanathan@sheffield.ac.uk [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, S1 3JD Sheffield (United Kingdom)

    2012-04-29

    Highlights: Black-Right-Pointing-Pointer Metal affinity based selective array for the screening of phosphometabolites. Black-Right-Pointing-Pointer A simple one-step plasma polymer coating and direct metal immobilisation. Black-Right-Pointing-Pointer ToF-SIMS detection of phosphometabolite array. Black-Right-Pointing-Pointer Ga and Zr suitable metals. - Abstract: Immobilised metal ion affinity (IMA) has been traditionally used specifically for the separation of phosphorylated proteins and nucleic acids, in proteomics and genomics, respectively. This report describes the novel application of IMA in metabolomics for the development of metabolite arrays to detect phosphometabolites using a plasma polymer-modified surface. Immobilisation of gallium, zirconium, cobalt, copper, zinc, nickel, iron, and chromium to acrylic acid plasma polymer followed by subsequent exposure to metabolites (phospho- and non-phosphometabolites) was investigated. Results analysed using ToF-SIMS suggests that gallium and zirconium exhibit higher phosphometabolite affinity and specificity compared to other metals, and can be used to develop metabolite arrays for the detection of phosphometabolites.

  15. Highly tunable plasmonic nanoring arrays for nanoparticle manipulation and detection

    Science.gov (United States)

    Sergides, M.; Truong, V. G.; Chormaic, S. Nic

    2016-09-01

    The advancement of trapping and detection of nano-objects at very low laser powers in the near-infra-red region (NIR) is crucial for many applications. Singular visible-light nano-optics based on abrupt phase changes have recently demonstrated a significant improvement in molecule detection. Here, we propose and demonstrate tunable plasmonic nanodevices, which can improve both the trapping field enhancement and detection of nano-objects using singular phase drops in the NIR range. The plasmonic nanostructures, which consist of gaps with dimensions 50 nm × 50 nm connecting nanorings in arrays is discussed. These gaps act as individual detection and trapping sites. The tunability of the system is evident from extinction and reflection spectra while increasing the aperture size in the arrays. Additionally, in the region where the plasmonic nano-array exhibits topologically-protected, near-zero reflection behaviour, the phase displays a rapid change. Our experimental data predict that, using this abrupt phase changes, one can improve the detection sensitivity by 10 times compared to the extinction spectra method. We finally report experimental evidence of 100 nm polystyrene beads trapping using low incident power on these devices. The overall design demonstrates strong capability as an optical, label-free, non-destructive tool for single molecule manipulation where low trapping intensity, minimal photo bleaching and high sensitivity is required.

  16. Application of Polyaniline Incorporated Carbon Particles Coated Platinum Electrode in Coulometric Titration to Determination of Polyisoprene Alcohol

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ge; LIU Meng; LIU Kuai-zhi; QU Jiang-ying; CHENG Gang; DU Zu-ling

    2003-01-01

    The feasibility of using electrodes modified with polyaniline incorporated carbon particles films for improving the precision of coulometric titration is demonstrated. The problem of large deviation produced during determining polyisoprene by coulometric titration with direct titration technique(double Pt electrodes indicating electrode) has been solved. In the titration process, polyisoprene alcohol, an electro-inactive species, is adsorbed on the surface of the bare Pt electrode, which inhibits the electrode reaction of Br- and Br2. Therefore, when the titration reaches the end-point, the detected current will slowly change with time, which can make the repeatability of end-point poor. The atomic force microscopic images show the morphology of the electrode surface of adsorbing polyisoprene alcohol. The application of the chemically modified electrode instead of the bare Pt electrode to indicating the end-point has been investigated. The results show that the Pt electrode coated with polyaniline incorporated carbon particles films is an excellent indicator electrode. This electrode has advantages that the indicating signals are sharp and repeatable at end-point. The precision and the accuracy of the determination of polyisoprene alcohol are satisfactory.

  17. Biomimetic MEMS sensor array for navigation and water detection

    Science.gov (United States)

    Futterknecht, Oliver; Macqueen, Mark O.; Karman, Salmah; Diah, S. Zaleha M.; Gebeshuber, Ille C.

    2013-05-01

    The focus of this study is biomimetic concept development for a MEMS sensor array for navigation and water detection. The MEMS sensor array is inspired by abstractions of the respective biological functions: polarized skylight-based navigation sensors in honeybees (Apis mellifera) and the ability of African elephants (Loxodonta africana) to detect water. The focus lies on how to navigate to and how to detect water sources in desert-like or remote areas. The goal is to develop a sensor that can provide both, navigation clues and help in detecting nearby water sources. We basically use the information provided by the natural polarization pattern produced by the sunbeams scattered within the atmosphere combined with the capability of the honeybee's compound eye to extrapolate the navigation information. The detection device uses light beam reactive MEMS, which are capable to detect the skylight polarization based on the Rayleigh sky model. For water detection we present various possible approaches to realize the sensor. In the first approach, polarization is used: moisture saturated areas near ground have a small but distinctively different effect on scattering and polarizing light than less moist ones. Modified skylight polarization sensors (Karman, Diah and Gebeshuber, 2012) are used to visualize this small change in scattering. The second approach is inspired by the ability of elephants to detect infrasound produced by underground water reservoirs, and shall be used to determine the location of underground rivers and visualize their exact routes.

  18. Pulsar timing arrays: the promise of gravitational wave detection.

    Science.gov (United States)

    Lommen, Andrea N

    2015-12-01

    We describe the history, methods, tools, and challenges of using pulsars to detect gravitational waves. Pulsars act as celestial clocks detecting gravitational perturbations in space-time at wavelengths of light-years. The field is poised to make its first detection of nanohertz gravitational waves in the next 10 years. Controversies remain over how far we can reduce the noise in the pulsars, how many pulsars should be in the array, what kind of source we will detect first, and how we can best accommodate our large bandwidth systems. We conclude by considering the important question of how to plan for a post-detection era, beyond the first detection of gravitational waves.

  19. Numerical simulations of odorant detection by biologically inspired sensor arrays.

    Science.gov (United States)

    Schuech, R; Stacey, M T; Barad, M F; Koehl, M A R

    2012-03-01

    The antennules of many marine crustaceans enable them to rapidly locate sources of odorant in turbulent environmental flows and may provide biological inspiration for engineered plume sampling systems. A substantial gap in knowledge concerns how the physical interaction between a sensing device and the chemical filaments forming a turbulent plume affects odorant detection and filters the information content of the plume. We modeled biological arrays of chemosensory hairs as infinite arrays of odorant flux-detecting cylinders and simulated the fluid flow around and odorant flux into the hair-like sensors as they intercepted a single odorant filament. As array geometry and sampling kinematics were varied, we quantified distortion of the flux time series relative to the spatial shape of the original odorant filament as well as flux metrics that may be important to both organisms and engineered systems attempting to measure plume structure and/or identify chemical composition. The most important predictor of signal distortion is the ratio of sensor diameter to odorant filament width. Achieving high peak properties (e.g. sharpness) of the flux time series and maximizing the total number of odorant molecules detected appear to be mutually exclusive design goals. Sensor arrays inspired specifically by the spiny lobster Panulirus argus and mantis shrimp Gonodactylaceus falcatus introduce little signal distortion but these species' neural systems may not be able to resolve plume structure at the level of individual filaments via temporal properties of the odorant flux. Current chemical sensors are similarly constrained. Our results suggest either that the spatial distribution of flux across the aesthetasc array is utilized by P. argus and G. falcatus, or that such high spatiotemporal resolution is unnecessary for effective plume tracking.

  20. Passive Detection of Narrowband Sources Using a Sensor Array

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, D H; Candy, J V; Guidry, B L

    2007-10-24

    In this report we derive a model for a highly scattering medium, implemented as a set of MATLAB functions. This model is used to analyze an approach for using time-reversal to enhance the detection of a single frequency source in a highly scattering medium. The basic approach is to apply the singular value decomposition to the multistatic response matrix for a time-reversal array system. We then use the array in a purely passive mode, measuring the response to the presence of a source. The measured response is projected onto the singular vectors, creating a time-reversal pseudo-spectrum. We can then apply standard detection techniques to the pseudo-spectrum to determine the presence of a source. If the source is close to a particular scatterer in the medium, then we would expect an enhancement of the inner product between the array response to the source with the singular vector associated with that scatterer. In this note we begin by deriving the Foldy-Lax model of a highly scattering medium, calculate both the field emitted by the source and the multistatic response matrix of a time-reversal array system in the medium, then describe the initial analysis approach.

  1. Wideband Array Signal Detection Algorithm Based on Power Focusing

    Directory of Open Access Journals (Sweden)

    Gong Bin

    2012-09-01

    Full Text Available Aiming at the requirement of real-time signal detection in the passive surveillance system, a wideband array signal detection algorithm is proposed based on the concept of power focusing. By making use of the phase difference of the signal received by a uniform linear array, the algorithm makes the power of the received signal focused in the Direction Of Arrival (DOA with improved cascade FFT. Subsequently, the probability density function of the output noise at each angle is derived. Furthermore, a Constant False Alarm Rate (CFAR test statistic and the corresponding detection threshold are constructed. The theoretical probability of detection is also derived for different false alarm rate and Signal-to-Noise Ratio (SNR. The proposed algorithm is computationally efficient, and the detection process is independent of the prior information. Meanwhile, the results can act as the initial value for other algorithms with higher precision. Simulation results show that the proposed algorithm achieves good performance for weak signal detection.

  2. Antibody-based protein detection using piezoresistive cantilever arrays

    Science.gov (United States)

    Dauksaite, Vita; Lorentzen, Martin; Besenbacher, Flemming; Kjems, Jørgen

    2007-03-01

    A piezoresistive cantilever array platform with electrical read-out was applied for protein detection using GST (glutathione-S-transferase) and GST antibodies as a model system. Sensing was performed in the static deflection mode under constant flow conditions. The GST antibodies were directly immobilized on the cantilever gold surface by means of free thiol groups. The setup allowed simultaneous deflection measurements with sensor and control-antibody-immobilized reference cantilevers and enabled detection of 1 ng µl-1 (40 nM) of GST protein, which is similar to the sensitivity reported for cantilever sensors using an optical read-out system.

  3. Coulometric differential FFT admittance voltammetry determination of Amlodipine in pharmaceutical formulation by nano-composite electrode.

    Science.gov (United States)

    Norouzi, Parviz; Gupta, Vinod Kumar; Larijani, Bagher; Rasoolipour, Solmaz; Faridbod, Farnoush; Ganjali, Mohammad R

    2015-01-01

    An electrochemical detection technique based on combination of was coulometric differential fast Fourier transformation admittance voltammetry (CDFFTAV) and nano-composite film modified glassy carbon electrode was successfully applied for sensitive determination of Amlodipine. The nano-composite film was made by a mixture of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), multiwall carbon nanotube and Au nanoparticles as electrochemical mediators. Studies reveal that the irreversible oxidation of Amlodipine was highly facile on the electrode surface. The electrochemical response was established on calculation of the charge under the admittance peak, which was obtained by discrete integration of the admittance response in a selected potential range, obtained in a flow injection analysis. Once established the best operative optimum conditions, the resulting nano-composite film electrode showed a catalytic effect on the oxidation of the analyte. The response is linear in the Amlodipine concentration range of 1.0 × 10(-9) to 2.0 × 10(-7)M with a detection limit of 1.25 × 10(-10)M. Moreover, the proposed technique exhibited high sensitivity, fast response time (less than 6s) and long-term stability and reproducibility around 96%, and it was successfully used to the determination of Amlodipine content in the pharmaceutical formulation.

  4. Towards robust gravitational wave detection with pulsar timing arrays

    Science.gov (United States)

    Cornish, Neil J.; Sampson, Laura

    2016-05-01

    Precision timing of highly stable millisecond pulsars is a promising technique for the detection of very low frequency sources of gravitational waves. In any single pulsar, a stochastic gravitational wave signal appears as an additional source of timing noise that can be absorbed by the noise model, and so it is only by considering the coherent response across a network of pulsars that the signal can be distinguished from other sources of noise. In the limit where there are many gravitational wave sources in the sky, or many pulsars in the array, the signals produce a unique tensor correlation pattern that depends only on the angular separation between each pulsar pair. It is this distinct fingerprint that is used to search for gravitational waves using pulsar timing arrays. Here we consider how the prospects for detection are diminished when the statistical isotropy of the timing array or the gravitational wave signal is broken by having a finite number of pulsars and a finite number of sources. We find the standard tensor-correlation analysis to be remarkably robust, with a mild impact on detectability compared to the isotropic limit. Only when there are very few sources and very few pulsars does the standard analysis begin to fail. Having established that the tensor correlations are a robust signature for detection, we study the use of "sky scrambles" to break the correlations as a way to increase confidence in a detection. This approach is analogous to the use of "time slides" in the analysis of data from ground-based interferometric detectors.

  5. Detection prospects of the Telescope Array hotspot by space observatories

    Science.gov (United States)

    Semikoz, D.; Tinyakov, P.; Zotov, M.

    2016-05-01

    In the present-day cosmic ray data, the strongest indication of anisotropy of the ultrahigh energy cosmic rays is the 20-degree hotspot observed by the Telescope Array with the statistical significance of 3.4 σ . In this work, we study the possibility of detecting such a spot by space-based all-sky observatories. We show that if the detected luminosity of the hotspot is attributed to a physical effect and not a statistical fluctuation, the KLYPVE and JEM-EUSO experiments would need to collect ˜300 events with E >57 EeV in order to detect the hotspot at the 5 σ confidence level with the 68% probability. We also study the dependence of the detection prospects on the hotspot luminosity.

  6. Towards Robust Gravitational Wave Detection with Pulsar Timing Arrays

    CERN Document Server

    Cornish, Neil J

    2015-01-01

    Precision timing of highly stable milli-second pulsars is a promising technique for the detection of very low frequency sources of gravitational waves. In any single pulsar, a stochastic gravitational wave signal appears as an additional source of timing noise that can be absorbed by the noise model, and so it is only by considering the coherent response across a network of pulsars that the signal can be distinguished from other sources of noise. In the limit where there are many gravitational wave sources in the sky, or many pulsars in the array, the signals produce a unique tensor correlation pattern that depends only on the angular separation between each pulsar pair. It is this distinct fingerprint that is used to search for gravitational waves using pulsar timing arrays. Here we consider how the prospects for detection are diminished when the statistical isotropy of the timing array or the gravitational wave signal is broken by having a finite number of pulsars and a finite number of sources. We find the...

  7. The high granularity and large solid angle detection array EXPADES

    Energy Technology Data Exchange (ETDEWEB)

    Strano, E., E-mail: estrano@pd.infn.it [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Anastasio, A. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Bettini, M. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Boiano, A. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Boiano, C. [INFN – Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Cassese, C. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Castellani, L.; Corti, D. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Di Meo, P. [INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Galet, G. [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Glodariu, T. [NIPNE, Str. Reactorului No. 30, P.O. Box MG-6, Bucharest-Magurele (Romania); Grebosz, J. [IFJ PAN, ul. Radzikowskiego 152, 31-342 Kraków (Poland); Guglielmetti, A. [Dipartimento di Fisica, Università di Milano, Via Celoria 16, I-20133 Milano (Italy); INFN – Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); La Commara, M. [Dipartimento di Scienze Fisiche, Università di Napoli, Via Cintia, I-80126 Napoli (Italy); INFN – Sezione di Napoli, Via Cintia, I-80126 Napoli (Italy); Manea, C. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Mazzocco, M.; Molini, P. [Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nicoletto, M. [INFN – Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); and others

    2013-12-15

    Highlights: • We realized a detection array for Exotic Radioactive Ion Beams. • High granularity (32 × 32 pixels 2 × 2 mm wide for 8 telescopes). • High solid angle (8 telescopes 64 × 64 mm wide in a cylindrical configuration covering up to 2.6 sr). • We tested each component of the array by both alpha particles and in-beam environment. • We measured the angular distribution for {sup 17}O elastic scattering on a {sup 58}Ni target. -- Abstract: The EXPADES (EXotic PArticle DEtection System) detector array consists of 16 Double Side Silicon Strip Detectors (DSSSD) with active areas of 64 × 64 mm{sup 2}, arranged in 8 ΔE (40/50 μm)–E (300 μm) telescopes. All detector faces are segmented into 32 × 2-mm wide strips, ensuring a 2 × 2 mm{sup 2} pixel configuration. Eight ionization chambers can be alternatively used as ΔE stages or, if needed, as an additional third layer for more complex triple telescopes. The signals from silicon ΔE layers and from ionization chambers are read by standard electronics, while innovative 32-channel ASIC chips are employed for the readout of the E stages. The results of off-line tests with alpha sources and from the first in-beam experiment with a {sup 17}O beam are presented.

  8. Non-specific sensor arrays for chemical detection

    Science.gov (United States)

    Johnson, Kevin; Minor, Christian

    2015-05-01

    Non-specific chemical sensor arrays have been the subject of considerable research efforts over the past thirty years with the idea that, by analogy to vertebrate olfaction, they are potentially capable of rendering complex chemical assessments with relatively modest logistical footprints. However, the actual implementation of such devices in challenging "real world" scenarios has arguably continued to fall short of these expectations. This work examines the inherent limitations of such devices for complex chemical sensing scenarios, placing them on a continuum between simple univariate sensors and complex multivariate analytical instrumentation and analyzing their utility in general-purpose chemical detection and accurate chemical sensing in the presence of unknown "unknowns." Results with simulated and acquired data sets are presented with discussion of the implications in development of chemical sensor arrays suitable for complex scenarios.

  9. Real-time threat detection using magnetometer arrays

    Science.gov (United States)

    Prouty, Mark D.; Tchernychev, Mikhail

    2016-05-01

    In this paper we present a discussion of using an array of atomic magnetometers to locate the presence of ferrous materials, such as concealed weapons, in real time. Ferrous materials create magnetic field anomalies. In order to determine the location of such objects, readings from many positions must be analyzed. This field inversion is typically done in post processing, once readings over a survey area or region of interest have been gathered. With the recent development of small and low power sensors, the dozen or so sensors required to provide information for magnetic field inversion may be deployed. We have built such an array and present here the results of using a realtime inversion algorithm. The inversion algorithm accurately determines target properties at a rate of 10 times per second as objects move past the array. Accuracies are as good as those obtained with target inversion methods used in analyzing data for unexploded ordnance detection. While those methods are typically applied in post processing, we show here those methods work even better when applied in real-time. We further present some analyses of the predicted performance of arrays in various geometries to address issues in security, such as crowd or perimeter monitoring. Target inversion methods may be accurately simulated, allowing for the development and testing of algorithms in an efficient manner. Additional processing may be done using the time history of the inversion results to remove false alarms and enhance detection. The key step is to start with an inversion method, utilizing the mathematical properties of magnetic fields and the known geometry of the measurements.

  10. Fluorescence detection in capillary arrays based on galvanometer step scanning.

    Science.gov (United States)

    Xue, G; Yeung, E S

    2001-10-01

    A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluoresceins is 3 x 10(-11) M (S/N = 3) for 5 mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  11. Gravitational-Wave Detection and Astrophysics with Pulsar Timing Arrays

    CERN Document Server

    Burke-Spolaor, Sarah

    2015-01-01

    We have begun an exciting era for gravitational wave detection, as several world-leading experiments are breaching the threshold of anticipated signal strengths. Pulsar timing arrays (PTAs) are pan-Galactic gravitational wave detectors that are already cutting into the expected strength of gravitational waves from cosmic strings and binary supermassive black holes in the nHz-$\\mu$Hz gravitational wave band. These limits are leading to constraints on the evolutionary state of the Universe. Here, we provide a broad review of this field, from how pulsars are used as tools for detection, to astrophysical sources of uncertainty in the signals PTAs aim to see, to the primary current challenge areas for PTA work. This review aims to provide an up-to-date reference point for new parties interested in the field of gravitational wave detection via pulsar timing.

  12. Lightning Mapping Array flash detection performance with variable receiver thresholds

    Science.gov (United States)

    Chmielewski, Vanna C.; Bruning, Eric C.

    2016-07-01

    This study characterizes Lightning Mapping Array performance for networks that participated in the Deep Convective Clouds and Chemistry field program using new Monte Carlo and curvature matrix model simulations. These open-source simulation tools are readily adapted to real-time operations or detailed studies of performance. Each simulation accounted for receiver threshold and location, as well as a reference distribution of source powers and flash sizes based on thunderstorm observations and the mechanics of station triggering. Source and flash detection efficiency were combined with solution bias and variability to predict flash area distortion at long ranges. Location errors and detection efficiency were highly dependent on the station configuration and thresholds, especially at longer ranges, such that performance varied more than expected across different networks and with azimuth within networks. Error characteristics matched prior studies, which led to an increase in flash distortion with range. Predicted flash detection efficiency exceeded 95% within 100 km of all networks.

  13. Acetylcholinesterase biosensor for carbaryl detection based on interdigitated array microelectrodes.

    Science.gov (United States)

    Gong, Zhili; Guo, Yemin; Sun, Xia; Cao, Yaoyao; Wang, Xiangyou

    2014-10-01

    In this study, an acetylcholinesterase (AChE) biosensor with superior accuracy and sensitivity was successfully developed based on interdigitated array microelectrodes (IAMs). IAMs have a series of parallel microband electrodes with alternating microbands connected together. Chitosan was used as the enzyme immobilization material, and AChE was used as the model enzyme for carbaryl detection to fabricate AChE biosensor. Electrochemical impedance spectroscopy was used in conjunction with the fabricated biosensor to detect pesticide residues. Based on the inhibition of pesticides on the AChE activity, using carbaryl as model compounds, the biosensor exhibited a wide range, low detection limit, and high stability. Moreover, the biosensor can also be used as a new promising tool for pesticide residue analysis.

  14. Flexible 16 Antenna Array for Microwave Breast Cancer Detection.

    Science.gov (United States)

    Bahramiabarghouei, Hadi; Porter, Emily; Santorelli, Adam; Gosselin, Benoit; Popović, Milica; Rusch, Leslie A

    2015-10-01

    Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2-4 GHz (with reflection coefficient (S11) below -10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively.

  15. WIMP detection and slow ion dynamics in carbon nanotube arrays.

    Science.gov (United States)

    Cavoto, G; Cirillo, E N M; Cocina, F; Ferretti, J; Polosa, A D

    2016-01-01

    Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs ([Formula: see text] GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with respect to CNT directions. New constraints are obtained on how to devise the CNT arrays to maximize the target channeling efficiency.

  16. Large Scale Plasmonic nanoCones array For Spectroscopy Detection

    KAUST Repository

    Das, Gobind

    2015-09-24

    Advanced optical materials or interfaces are gaining attention for diagnostic applications. However, the achievement of large device interface as well as facile surface functionalization largely impairs their wide use. The present work is aimed to address different innovative aspects related to the fabrication of large area 3D plasmonic arrays, their direct and easy functionalization with capture elements and their spectroscopic verifications through enhanced Raman and enhanced fluorescence techniques. In detail we have investigated the effect of Au-based nanoCones array, fabricated by means of direct nanoimprint technique over large area (mm2), on protein capturing and on the enhancement in optical signal. A selective functionalization of gold surfaces was proposed by using a peptide (AuPi3) previously selected by phage display. In this regard, two different sequences, labeled with fluorescein and biotin, were chemisorbed on metallic surfaces. The presence of Au nanoCones array consents an enhancement in electric field on the apex of cone, enabling the detection of molecules. We have witnessed around 12-fold increase in fluorescence intensity and SERS enhancement factor around 1.75 ×105 with respect to the flat gold surface. Furthermore, a sharp decrease in fluorescence lifetime over nanoCones confirms the increase in radiative emission (i.e. an increase in photonics density at the apex of cones).

  17. WIMP detection and slow ion dynamics in carbon nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Cavoto, G. [INFN Sezione di Roma, Rome (Italy); Cirillo, E.N.M. [Sapienza Universita di Roma, Dipartimento SBAI, Rome (Italy); Cocina, F. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); Ferretti, J. [Sapienza Universita di Roma, Dipartimento di Fisica (Italy); INFN Sezione di Roma, Rome (Italy); Polosa, A.D. [Sapienza Universita di Roma, Dipartimento di Fisica (Italy); CERN, Theory Division, Geneva (Switzerland); INFN Sezione di Roma, Rome (Italy)

    2016-06-15

    Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs (∼ 11 GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with respect to CNT directions. New constraints are obtained on how to devise the CNT arrays to maximize the target channeling efficiency. (orig.)

  18. Diaphragm-free cell for trace determination of water based on the karl Fischer reaction using continuous coulometric titration.

    Science.gov (United States)

    Cedergren, A; Jonsson, S

    1997-08-01

    A new type of diaphragm-free coulometric cell for continuous coulometric Karl Fischer titrations of water in the range 0.1-1000 μg is described. The relative standard deviation obtained for titrations of 1 μg amounts of water was typically 1%. The background due to diffusion of water from the air was normally in the range 0.3-0.9 μg of water min(-1) depending on environmental humidity. The variation in the background was normally ±0.01 μg min(-1). The construction makes it possible, at any time in a sequence of titrations, to renew the catholyte by means of a Teflon plunger inside the cathode compartment. In this way, the interference effects caused by oxidizable reduction products of methyl sulfite which are formed at the cathode can be controlled in a very simple way. These products are rapidly eliminated by means of a normal titration before a new titration starts. The need for this draining step differs depending on the type of reagent used. The coulometric titration system makes use of true potentiometric end-point detection, and this principle makes it possible to control the iodine level at the end-point at much lower levels as compared with commercial instrumentation. The analytical advantages gained by this option are demonstrated for the determination of water in ethylenediamine, a task which was found to be impossible when using end-point concentrations in the range (3-7) × 10(-5) M, which is typical for the bipotentiometric indicating system used in commercial instruments. Recovery rates in the range 100-102% were obtained and are shown to be dependent on the type of reagent used. The most accurate results were obtained for an imidazole-buffered methanolic reagent in which the concentration of sulfur dioxide was kept relatively low (0.10 M). The diaphragm-free cell described was shown to be compatible with all of the commercial reagents (designed for coulometry) investigated, including the well-known Hydranal products Coulomat A, AK, AG, AG-H, and

  19. Flexible sixteen monopole antenna array for microwave breast cancer detection.

    Science.gov (United States)

    Bahrami, H; Porter, E; Santorelli, A; Gosselin, B; Popovic, M; Rusch, L A

    2014-01-01

    Radar based microwave imaging (MI) has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues over a wide frequency band has been made possible by ultra-wideband (UWB) techniques. In this paper, a flexible, compact monopole antenna on a 100 μm Kapton polyimide is designed, using a high frequency structure simulator (HFSS), to be in contact with biological breast tissues over the 2-5GHz frequency range. The antenna parameters are optimized to obtain a good impedance match over the required frequency range. The designed antenna size is 18mm × 18mm. Further, a flexible conformal 4×4 ultra-wideband antenna array, in a format similar to that of a bra, was developed for a radar-based breast cancer detection system.

  20. Lenslet array to further suppress starlight for direct exoplanet detection

    Science.gov (United States)

    Gong, Qian; McElwain, Michael; Shiri, Ron

    2016-07-01

    Direct imaging plays a key role in the detection and characterization of exoplanets orbiting within its host star's habitable zone. Many innovative ideas for starlight suppression and wavefront control have been proposed and developed over the past decade. However, several technological challenges still lie ahead to achieve the required contrast, including controlling the observatory pointing performance, fabricating occulting masks with tight optical tolerances, developing wavefront control algorithms, controlling stray light, advancing single photon detecting detectors, and integrated system-level issues. This paper explores how a lenslet array and pinhole mask may be implemented to further suppress uncorrected starlight that leaks through the occulting mask. An external occulter, or star shade, is simulated to demonstrate this concept, although this approach can be implemented for internal coronagraphs as well. We describe how to use simple relay optics to control the scene near the inner working angle and the level of the suppression expected. Furthermore, if the lenslet array is the input to an integral field spectrograph, as planned for the WFIRST mission, the spectral content of the exoplanet atmospheres can be obtained to determine if the observed planet is habitable and ultimately, if it is inhabited.

  1. Nanoscale optofluidic sensor arrays for Dengue virus detection

    Science.gov (United States)

    Mandal, Sudeep; Akhmechet, Roman; Chen, Likun; Nugen, Sam; Baeumner, Antje; Erickson, David

    2007-09-01

    Here we present our work towards the development of Nanoscale Optofluidic Sensor Arrays (NOSA), which is an optofluidic architecture for performing label free, highly parallel, detections of biomolecular interactions. The approach is based on the use of optically resonant devices whose resonant wavelength is shifted due to a local change in refractive index caused by a positive binding event between a surface bound molecule and it solution phase target. A special two stage micro-/nanofluidics architecture is used to first functionalize the devices and then to deliver the targets. Two variants of the NOSA will be presented here. The first approach utilizes a 1D resonant cavity in a 1D silicon-on-insulator (SOI) waveguide with a unique differential size functionalization approach. This approach allows binding events at one or at a combination of the many sensing sites which causes a unique shift in the output resonator spectrum. The latter approach consists of a SOI waveguide evanescently coupled to multiple 1-D photonic crystal resonators of different sizes along the length, each of which is functionalized with a different oligonucleotide probe. These devices have an extremely low limit of detection and are compatible with aqueous environments. The primary advantage of these devices over existing technology is that it combines the sensitivity (limit of detection) of nanosensor technology with the parallelism of the microarray type format. Our initial application is in the detection of viral RNA of Dengue virus.

  2. WIMP detection and slow ion dynamics in carbon nanotube arrays

    CERN Document Server

    Cavoto, G; Cocina, F; Ferretti, J; Polosa, A D

    2016-01-01

    Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs (~ 10 GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with ...

  3. Comparison of Affymetrix Gene Array with the Exon Array shows potential application for detection of transcript isoform variation

    Directory of Open Access Journals (Sweden)

    Coulombe-Huntington Jasmin

    2009-11-01

    Full Text Available Abstract Background The emergence of isoform-sensitive microarrays has helped fuel in-depth studies of the human transcriptome. The Affymetrix GeneChip Human Exon 1.0 ST Array (Exon Array has been previously shown to be effective in profiling gene expression at the isoform level. More recently, the Affymetrix GeneChip Human Gene 1.0 ST Array (Gene Array has been released for measuring gene expression and interestingly contains a large subset of probes from the Exon Array. Here, we explore the potential of using Gene Array probes to assess expression variation at the sub-transcript level. Utilizing datasets of the high quality Microarray Quality Control (MAQC RNA samples previously assayed on the Exon Array and Gene Array, we compare the expression measurements of the two platforms to determine the performance of the Gene Array in detecting isoform variations. Results Overall, we show that the Gene Array is comparable to the Exon Array in making gene expression calls. Moreover, to examine expression of different isoforms, we modify the Gene Array probe set definition file to enable summarization of probe intensity values at the exon level and show that the expression profiles between the two platforms are also highly correlated. Next, expression calls of previously known differentially spliced genes were compared and also show concordant results. Splicing index analysis, representing estimates of exon inclusion levels, shows a lower but good correlation between platforms. As the Gene Array contains a significant subset of probes from the Exon Array, we note that, in comparison, the Gene Array overlaps with fewer but still a high proportion of splicing events annotated in the Known Alt Events UCSC track, with abundant coverage of cassette exons. We discuss the ability of the Gene Array to detect alternative splicing and isoform variation and address its limitations. Conclusion The Gene Array is an effective expression profiling tool at gene and

  4. High Density Nano-Electrode Array for Radiation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Mano Misra

    2010-05-07

    Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 ºC. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29x1013 cm-3, 1.56 eV and 2.76x1011Ω-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 μCi), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the

  5. Array processing——a new method to detect and correct errors on array resistivity logging tool measurements

    Institute of Scientific and Technical Information of China (English)

    Philip D.RABINOWITZ; Zhiqiang ZHOU

    2007-01-01

    In recent years more and more multi-array logging tools, such as the array induction and the array lateralog, are applied in place of conventional logging tools resulting in increased resolution, better radial and vertical sounding capability and other features. Multi-array logging tools acquire several times more individual measurements than conventional logging tools. In addition to new information contained in these data, there is a certain redundancy among the measurements. The sum of the measurements actually composes a large matrix. Providing the measurements are error-free, the elements of this matrix show certain consistencies. Taking advantage of these consistencies, an innovative method is developed to detect and correct errors in the array resistivity logging tool raw measurements, and evaluate the quality of the data. The method can be described in several steps. First, data consistency patterns are identified based onthe physics of the measurements. Second, the measurements are compared against the consistency patterns for error and bad data detection. Third, the erroneous data are eliminated and the measurements are re-constructed according to the consistency patterns. Finally, the data quality is evaluated by comparing the raw measurements with the re-constructed measurements. The method can be applied to all array type logging tools, such as array induction tool and array resistivity tool. This paper describes the method and illustrates its application with the High Definition Lateral Log (HDLL, Baker Atlas) instrument. To demonstrate the efficiency of the method, several field examples are shown and discussed.

  6. A porous actuator for an Isfet-based coulometric sensor-actuator system

    NARCIS (Netherlands)

    Luo, J.; Olthuis, W.; Bergveld, P.; Linden, van der W.E.; Bos, M.

    1991-01-01

    The previously developed prototype ISFET (ion-sensitive field effect transistor)-based coulometric sensor-actuator system suffers from delay in response due to the nonzero distance between the sensor and actuator. The authors describe a novel configuration of a sensor-actuator device which employs a

  7. A porous actuator for an Isfet-based coulometric sensor-actuator system

    NARCIS (Netherlands)

    Luo, J.; Luo, J.; Olthuis, Wouter; Bergveld, Piet; van der Linden, W.E.; Bos, M.

    1991-01-01

    The previously developed prototype ISFET (ion-sensitive field effect transistor)-based coulometric sensor-actuator system suffers from delay in response due to the nonzero distance between the sensor and actuator. The authors describe a novel configuration of a sensor-actuator device which employs a

  8. Spatio-temporal change detection from multidimensional arrays: Detecting deforestation from MODIS time series

    Science.gov (United States)

    Lu, Meng; Pebesma, Edzer; Sanchez, Alber; Verbesselt, Jan

    2016-07-01

    Growing availability of long-term satellite imagery enables change modeling with advanced spatio-temporal statistical methods. Multidimensional arrays naturally match the structure of spatio-temporal satellite data and can provide a clean modeling process for complex spatio-temporal analysis over large datasets. Our study case illustrates the detection of breakpoints in MODIS imagery time series for land cover change in the Brazilian Amazon using the BFAST (Breaks For Additive Season and Trend) change detection framework. BFAST includes an Empirical Fluctuation Process (EFP) to alarm the change and a change point time locating process. We extend the EFP to account for the spatial autocorrelation between spatial neighbors and assess the effects of spatial correlation when applying BFAST on satellite image time series. In addition, we evaluate how sensitive EFP is to the assumption that its time series residuals are temporally uncorrelated, by modeling it as an autoregressive process. We use arrays as a unified data structure for the modeling process, R to execute the analysis, and an array database management system to scale computation. Our results point to BFAST as a robust approach against mild temporal and spatial correlation, to the use of arrays to ease the modeling process of spatio-temporal change, and towards communicable and scalable analysis.

  9. Damage Detection in Composite Structures with Wavenumber Array Data Processing

    Science.gov (United States)

    Tian, Zhenhua; Leckey, Cara; Yu, Lingyu

    2013-01-01

    Guided ultrasonic waves (GUW) have the potential to be an efficient and cost-effective method for rapid damage detection and quantification of large structures. Attractive features include sensitivity to a variety of damage types and the capability of traveling relatively long distances. They have proven to be an efficient approach for crack detection and localization in isotropic materials. However, techniques must be pushed beyond isotropic materials in order to be valid for composite aircraft components. This paper presents our study on GUW propagation and interaction with delamination damage in composite structures using wavenumber array data processing, together with advanced wave propagation simulations. Parallel elastodynamic finite integration technique (EFIT) is used for the example simulations. Multi-dimensional Fourier transform is used to convert time-space wavefield data into frequency-wavenumber domain. Wave propagation in the wavenumber-frequency domain shows clear distinction among the guided wave modes that are present. This allows for extracting a guided wave mode through filtering and reconstruction techniques. Presence of delamination causes spectral change accordingly. Results from 3D CFRP guided wave simulations with delamination damage in flat-plate specimens are used for wave interaction with structural defect study.

  10. [Use of coulometric titration for elucidating the mechanism of the oxidation of 6-APA alkaline breakdown products by halogens].

    Science.gov (United States)

    Kharlamov, V T; Inkin, A A; Ermolina, G E

    1975-02-01

    Penaldinic acid and penicillamine were formed on alkali decomposition (1 N NaOH) of 6-APA for 20 minutes at room temperature, penicillamine being completely oxidized to disulphide by the air oxygen. Coulometric titration of the alkali decomposition products showed that generated chlorine in 0.5 N HCl solution or bromine in a week acid solution of KBr oxidized them with participation of 7 electrones. Generated iodine did not practically oxidize the 6-APA decomposition products during the coulometric titration.

  11. Superconducting Tunnel Junction Arrays for UV Photon Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative method is described for the fabrication of superconducting tunnel junction (STJ) detector arrays offering true "three dimensional" imaging throughout...

  12. Comparative analysis of copy number detection by whole-genome BAC and oligonucleotide array CGH

    Directory of Open Access Journals (Sweden)

    Bejjani Bassem A

    2010-06-01

    Full Text Available Abstract Background Microarray-based comparative genomic hybridization (aCGH is a powerful diagnostic tool for the detection of DNA copy number gains and losses associated with chromosome abnormalities, many of which are below the resolution of conventional chromosome analysis. It has been presumed that whole-genome oligonucleotide (oligo arrays identify more clinically significant copy-number abnormalities than whole-genome bacterial artificial chromosome (BAC arrays, yet this has not been systematically studied in a clinical diagnostic setting. Results To determine the difference in detection rate between similarly designed BAC and oligo arrays, we developed whole-genome BAC and oligonucleotide microarrays and validated them in a side-by-side comparison of 466 consecutive clinical specimens submitted to our laboratory for aCGH. Of the 466 cases studied, 67 (14.3% had a copy-number imbalance of potential clinical significance detectable by the whole-genome BAC array, and 73 (15.6% had a copy-number imbalance of potential clinical significance detectable by the whole-genome oligo array. However, because both platforms identified copy number variants of unclear clinical significance, we designed a systematic method for the interpretation of copy number alterations and tested an additional 3,443 cases by BAC array and 3,096 cases by oligo array. Of those cases tested on the BAC array, 17.6% were found to have a copy-number abnormality of potential clinical significance, whereas the detection rate increased to 22.5% for the cases tested by oligo array. In addition, we validated the oligo array for detection of mosaicism and found that it could routinely detect mosaicism at levels of 30% and greater. Conclusions Although BAC arrays have faster turnaround times, the increased detection rate of oligo arrays makes them attractive for clinical cytogenetic testing.

  13. Defects detection in thin components using two-dimensional ultrasonic arrays

    Science.gov (United States)

    Velichko, A.; Wilcox, P. D.; Drinkwater, B. W.

    2013-01-01

    The use of 2D ultrasonic arrays provides great flexibility, as one array probe allows a given defect to be illuminated from a wide range of angles. However there are a number of challenges in the application of 2D arrays to detection and characterization of 3D defects. In the current paper the problem of finding the optimal array configuration for defects detection in thin sections is investigated. The efficient FE scattering model is used to simulate an ultrasonic array response for different 3D defects. The data provided by this model is then used to analyze the influence of different parameters on the array performance (signal to noise ratio, sensitivity, resolution). Finally, experimental results are shown that illustrate the imaging performance of optimal 2D array configuration.

  14. Determination of arsenic(III), sulphite and sulphur dioxide using the triangle programmed coulometric titration principle

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, F.; Buschmann, N. (Muenster Univ. (Germany, F.R.))

    1990-11-01

    In 1975, Pungor et al. established a new method called Triangle Programmed Coulometric Titration, which allows to titrate flowing sample solutions. The following paper presents a new analytical procedure for the determination of sulphur dioxide based on this technique. To obtain this, sulphur dioxide was transferred across a semipermeable membrane from a gaseous phase into an aqueous acceptor phase. Then the SO{sub 2}-concentration of the streaming aqueous phase was analysed bromometrically using the Triangle Programmed Coulometric Titration principle. The titration curves were followed continuously by an AC-bivoltammetric flow-through detector. Using this procedure a determination of SO{sub 2} concentrations between 400 and 2500 mg/m{sup 3} was possible.(orig.).

  15. High-Throughput DNA Array for SNP Detection of KRAS Gene Using a Centrifugal Microfluidic Device.

    Science.gov (United States)

    Sedighi, Abootaleb; Li, Paul C H

    2016-01-01

    Here, we describe detection of single nucleotide polymorphism (SNP) in genomic DNA samples using a NanoBioArray (NBA) chip. Fast DNA hybridization is achieved in the chip when target DNAs are introduced to the surface-arrayed probes using centrifugal force. Gold nanoparticles (AuNPs) are used to assist SNP detection at room temperature. The parallel setting of sample introduction in the spiral channels of the NBA chip enables multiple analyses on many samples, resulting in a technique appropriate for high-throughput SNP detection. The experimental procedure, including chip fabrication, probe array printing, DNA amplification, hybridization, signal detection, and data analysis, is described in detail.

  16. Detection of wheel rim by immersion scan of phased array ultrasonic flaw testing

    Science.gov (United States)

    Cai, Yi-He; Guo, Jian-qiang; Wang, Ze-yong; Gao, Xiao-rong; Jiang, Xiang-dong; Li, Xi

    2015-02-01

    In order to achieve the in-service detection to high speed train wheel rims, this article analyzed the effects of the number of array elements to image focusing and image quality using water immersion ultrasonic phased array technology. Also, the effects of the depth of water to detecting technique had been researched. According to the results of the experiments, the number of optimal array elements, the corresponding thickness of immersion layer, and the optimal range of water's depth had been obtained. Thus, appropriate references had been provided to water immersion ultrasonic phased array testing.

  17. The coulometric titration of acids and bases in m-cresol medium

    NARCIS (Netherlands)

    Bos, M.; Dahmen, E.A.M.F.

    1974-01-01

    A method is described for the coulometric titration of acids and bases in the solvent m-cresol. The method is suitable for bases with pKa values greater than 11 in m-cresol, or for acids with pKa values below 13 in m-cresol. Amounts of 5–50 μeq of acid or base can be determined with a relative

  18. DETERMINATION OF WATER CONTENT IN PYROLYTIC TARS USING COULOMETRIC KARL-FISHER TITRATION

    Directory of Open Access Journals (Sweden)

    Lenka Jílková

    2017-02-01

    Full Text Available The liquid organic fraction of pyrolytic tar has a high energy value which makes possible its utilization as an energy source. However, before utilization, it is crucial to remove water from the liquid fraction. The presence of water reduces the energy value of pyrolytic tars. Water separation from the organic tar fraction is a complex process, since an emulsion can be readily formed. Therefore, after phase separation, it is important to know the residual water content in the organic phase and whether it is necessary to further dry it. The results presented in this manuscript focus on a water determination in liquid products from coal and biomass pyrolysis by a coulometric Karl‑Fischer titration. The Coulometric Karl‑Fischer titration is often used for a water content determination in gaseous, liquid and solid samples. However, to date, this titration method has not been used for a water determination in tars. A new water determination method, which has been tested on different types of tar, has been developed. The Coulometric Karl‑Fischer titration is suitable for tar samples with a water content not greater than 5 wt. %. The obtained experimental results indicate that the new introduced method can be used with a very good repeatability for a water content determination in tars.

  19. Coulometric Karl Fischer titration of trace water in diaphragm-free cells.

    Science.gov (United States)

    Larsson, William; Cedergren, Anders

    2005-03-15

    Factors influencing the accuracy and precision for diaphragm-free Karl Fischer coulometric determinations of low mug-amounts of water have been studied using the Metrohm 756 (pulsed current) coulometer and eight different types of commercial coulometric reagents and some modifications of these. As in the case of diaphragm-free coulometric titration of large amounts of water, the positive errors, due to the formation of oxidizable reduction products (of sulfur dioxide) in the cathode reaction (besides hydrogen), were found to be minimized by the use of highest possible pulse current (in the range 100-400mA) in combination with the fastest possible titration rate. Most accurate (102-103%) and precise results (typical relative standard deviation 1.8%) were obtained for reagents containing very large concentrations of imidazole in combination with the presence of modifiers like hexanol, chloroform and propylene glycol (i.e. the HYDRA-POINT reagents). Similar results were obtained when this type of reagent was mixed 60/40 with xylene according to the ASTM recommendation for water determinations in petroleum products like crude and lubricating oils. Addition of decanol to this type of reagent mixture was found to reduce the influence from the oxidative reduction products significantly. A reduction of the error from 3.6% relative to 1.6% was achieved by addition of 9% (v/v) of decanol to a 60/40 reagent mixture of HYDRA-POINT Coulometric Gen (containing hexanol as modifier) and xylene. For larger concentrations of decanol the pulse current had to be lowered to 100mA and this might explain why no further improvement was observed. An additional attempt to minimize the interference by lowering the concentration of sulfur dioxide in the reagents gave no significant effect. However, by means of a home-built computer-controlled coulometric instrumentation based on continuous instead of pulsed current (including a large cathodic current density) it was possible to achieve

  20. SERS based immuno-microwell arrays for multiplexed detection of foodborne pathogenic bacteria

    Science.gov (United States)

    Sun, Jian; Hankus, Mikella E.; Cullum, Brian M.

    2009-05-01

    A novel surface enhanced Raman scattering (SERS)-based immuno-microwell array has been developed for multiplexed detection of foodborne pathogenic bacteria. The immuno-microwell array was prepared by immobilizing the optical addressable immunomagnetic beads (IMB) into the microwell array on one end of a fiber optic bundle. The IMBs, magnetic beads coated with specific antibody to specific bacteria, were used for immunomagnetic separation (IMS) of corresponding bacteria. The magnetic separation by the homemade magnetic separation system was evaluated in terms of the influences of several important parameters including the beads concentration, the sample volume and the separation time. IMS separation efficiency of the model bacteria E.coli O157:H7 was 63% in 3 minutes. The microwell array was fabricated on hydrofluoric acid etched end of a fiber optic bundle containing 30,000 fiber elements. After being coated with silver, the microwell array was used as a uniform SERS substrate with the relative standard deviation of the SERS enhancement across the microwell array < 2% and the enhancement factor as high as 2.18 x 107. The antibody modified microwell array was prepared for bacteria immobilization into the microwell array, which was characterized by a sandwich immunoassay. To demonstrate the potential of multiplexed SERS detection with the immuno-microwell array, the SERS spectra of different Raman dye labeled magnetic beads as well as mixtures were measured on the mircrowell array. In bead mixture, different beads were identified by the characteristic SERS bands of the corresponding Raman label.

  1. Compressive Sensing for Blockage Detection in Vehicular Millimeter Wave Antenna Arrays

    KAUST Repository

    Eltayeb, Mohammed E.

    2017-02-07

    The radiation pattern of an antenna array depends on the excitation weights and the geometry of the array. Due to mobility, some vehicular antenna elements might be subjected to full or partial blockages from a plethora of particles like dirt, salt, ice, and water droplets. These particles cause absorption and scattering to the signal incident on the array, and as a result, change the array geometry. This distorts the radiation pattern of the array mostly with an increase in the sidelobe level and decrease in gain. In this paper, we propose a blockage detection technique for millimeter wave vehicular antenna arrays that jointly estimates the locations of the blocked antennas and the attenuation and phase-shifts that result from the suspended particles. The proposed technique does not require the antenna array to be physically removed from the vehicle and permits real-time array diagnosis. Numerical results show that the proposed technique provides satisfactory results in terms of block detection with low detection time provided that the number of blockages is small compared to the array size.

  2. Pyroelectric sensor arrays for detection and thermal imaging

    Science.gov (United States)

    Holden, Anthony J.

    2013-06-01

    Penetration of uncooled (room temperature operation) thermal detector arrays into high volume commercial products depends on very low cost technology linked to high volume production. A series of innovative and revolutionary developments is now allowing arrays based on bulk pyroelectric ceramic material to enter the consumer marketplace providing everything from sophisticated security and people monitoring devices to hand held thermal imagers and visual IR thermometers for preventative maintenance and building inspection. Although uncooled resistive microbolometer detector technology has captured market share in higher cost thermal imager products we describe a pyroelectric ceramic technology which does not need micro electro-mechanical systems (MEMS) technology and vacuum packaging to give good performance. This is a breakthrough for very low cost sensors and imagers. Recent developments in a variety of products based on pyroelectric ceramic arrays are described and their performance and applicability compared and contrasted with competing technologies.

  3. Genome Fusion Detection: a novel method to detect fusion genes from SNP-array data.

    Science.gov (United States)

    Thieme, Sebastian; Groth, Philip

    2013-03-15

    Fusion genes result from genomic rearrangements, such as deletions, amplifications and translocations. Such rearrangements can also frequently be observed in cancer and have been postulated as driving event in cancer development. to detect them, one needs to analyze the transition region of two segments with different copy number, the location where fusions are known to occur. Finding fusion genes is essential to understanding cancer development and may lead to new therapeutic approaches. Here we present a novel method, the Genomic Fusion Detection algorithm, to predict fusion genes on a genomic level based on SNP-array data. This algorithm detects genes at the transition region of segments with copy number variation. With the application of defined constraints, certain properties of the detected genes are evaluated to predict whether they may be fused. We evaluated our prediction by calculating the observed frequency of known fusions in both primary cancers and cell lines. We tested a set of cell lines positive for the BCR-ABL1 fusion and prostate cancers positive for the TMPRSS2-ERG fusion. We could detect the fusions in all positive cell lines, but not in the negative controls.

  4. Radiation detection from phase-locked serial dc SQUID arrays

    DEFF Research Database (Denmark)

    Kaplunenko, V. K.; Mygind, Jesper; Pedersen, Niels Falsig

    1993-01-01

    on the external loading. For small loading it was N times smaller than expected for a single cell. The influence of the inductive coupling mechanism on the operation of discrete Josephson junction circuits and the similarity to the coupling in layered structures of long Josephson junctions is discussed. Journal......We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac...

  5. Spatio-temporal change detection from multidimensional arrays

    NARCIS (Netherlands)

    Lu, Meng; Pebesma, Edzer; Sanchez, Alber; Verbesselt, Jan

    2016-01-01

    Growing availability of long-term satellite imagery enables change modeling with advanced spatio-temporal statistical methods. Multidimensional arrays naturally match the structure of spatio-temporal satellite data and can provide a clean modeling process for complex spatio-temporal analysis over

  6. Vapor Phase Detection Using Chemi-Resistor Sensor Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Nathan S. Lewis

    1999-02-17

    This paper focuses on two main areas: understanding sensor response times so as to obtain improved time response in the field when needed for vapor tracking and classification, and improved theoretical understanding of the sensor response properties that generate the pattern on the array in response to a given analyte.

  7. Detection and Discrimination in One-Pass Using the OPTEMA Towed-Array

    Science.gov (United States)

    2014-11-01

    INTERIM TECHNICAL REPORT Detection and Discrimination in One-Pass Using the OPTEMA Towed-Array ESTCP Project MR-201225 NOVEMBER 2014...2014 4. TITLE AND SUBTITLE Detection and Discrimination in One-Pass Using the OPTEMA Towed Array: APG Standardized UXO Demonstration Site Technical...vs. probability of false positive for ranking assignments based on classification decisions ( discrimination ). The black solid line indicates our

  8. Gold nanoparticle wire and integrated wire array for electronic detection of chemical and biological molecules

    Directory of Open Access Journals (Sweden)

    J. J. Diao

    2011-03-01

    Full Text Available Nanoparticle wire and integrated nanoparticle wire array have been prepared through a green technique: discontinuous vertical evaporation-driven colloidal deposition. The conducting gold nanoparticle wire made by this technique shows ability for the sensitive electronic detection of chemical and biological molecules due to its high surface to volume ratio. Furthermore, we also demonstrate a potential usage of integrated gold nanoparticle wire array for the localized detection.

  9. Detection and Discrimination in One Pass Using the OPTEMA Towed Array

    Science.gov (United States)

    2017-02-21

    MR-201225) Detection and Discrimination in One-Pass Using the OPTEMA Towed-Array February 2017 This document has been cleared for public release...Dec. 2016 4. TITLE AND SUBTITLE Detection and Discrimination in One-Pass Using the OPTEMA Towed Array: Final Technical Report, Former...existing process with minimal impact to the overall flow. This process has demonstrated significant success for discriminating Targets of Interest

  10. Ancient pathogen DNA in archaeological samples detected with a Microbial Detection Array.

    Science.gov (United States)

    Devault, Alison M; McLoughlin, Kevin; Jaing, Crystal; Gardner, Shea; Porter, Teresita M; Enk, Jacob M; Thissen, James; Allen, Jonathan; Borucki, Monica; DeWitte, Sharon N; Dhody, Anna N; Poinar, Hendrik N

    2014-03-06

    Ancient human remains of paleopathological interest typically contain highly degraded DNA in which pathogenic taxa are often minority components, making sequence-based metagenomic characterization costly. Microarrays may hold a potential solution to these challenges, offering a rapid, affordable, and highly informative snapshot of microbial diversity in complex samples without the lengthy analysis and/or high cost associated with high-throughput sequencing. Their versatility is well established for modern clinical specimens, but they have yet to be applied to ancient remains. Here we report bacterial profiles of archaeological and historical human remains using the Lawrence Livermore Microbial Detection Array (LLMDA). The array successfully identified previously-verified bacterial human pathogens, including Vibrio cholerae (cholera) in a 19th century intestinal specimen and Yersinia pestis ("Black Death" plague) in a medieval tooth, which represented only minute fractions (0.03% and 0.08% alignable high-throughput shotgun sequencing reads) of their respective DNA content. This demonstrates that the LLMDA can identify primary and/or co-infecting bacterial pathogens in ancient samples, thereby serving as a rapid and inexpensive paleopathological screening tool to study health across both space and time.

  11. X-ray detection with a linear silicon photo-diode array

    Energy Technology Data Exchange (ETDEWEB)

    Zutavern, F.; Aton, T.; Franck, C; Schnatterly, S.

    1982-01-01

    A phosphor-coated silicon photo-diode array has been used as the detector in an ultra-high vacuum, soft X-ray emission spectrograph. In developing this detection system, measurements on a bare array, a phosphor coated array, and a phosphor coated photo-multiplier tube were made at the Synchrotron Ultraviolet Radiation Facility (SURF), NBS, Washington, D.C. The results of these measurements and the performance of this detection system will be discussed. These results will then be extrapolated into the X-ray energy range used by crystallographers.

  12. Precise annealing of focal plane arrays for optical detection

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Daniel A.

    2015-09-22

    Precise annealing of identified defective regions of a Focal Plane Array ("FPA") (e.g., exclusive of non-defective regions of the FPA) facilitates removal of defects from an FPA that has been hybridized and/or packaged with readout electronics. Radiation is optionally applied under operating conditions, such as under cryogenic temperatures, such that performance of an FPA can be evaluated before, during, and after annealing without requiring thermal cycling.

  13. Biomimetic Nanosensor Arrays for Selective Small Molecule Detection

    Science.gov (United States)

    2012-02-21

    precluding the possibility of implantable or wearable sensors, and requires skilled human operators. Arrays of chemical sensors (“electronic noses...using peptide sequences that were rationally designed to mimic the putative binding sites of a human olfactory protein.16 The protein was modeled by...Apis mellifera, contains a C-terminal tail fragment that has been shown to bind to pheromones and other chemical targets.22 Four amino acid

  14. Interference-free coulometric titration of water in lithium bis(oxalato)borate using Karl Fischer reagents based on N-methylformamide.

    Science.gov (United States)

    Larsson, William; Panitz, Jan-Christoph; Cedergren, Anders

    2006-03-15

    A non-alcoholic coulometric reagent based on N-methylformamide (NMF) was shown to eliminate the severe interference effect caused by the alcohol component of the conventional Karl Fischer (KF) reagent on the battery electrolyte lithium bis(oxalato)borate (LiBOB). For sample amounts up to 240 microg of water, the stoichiometry of the KF reaction deviated only slightly from the ideal 1:1 ratio for the best reagent composition. Both solid and dissolved (in acetonitrile, tetrahydrofuran (THF), and ethylene carbonate/ethyl methyl carbonate) LiBOB were titrated successfully using a Metrohm 756 KF Coulometer with a diaphragm cell. The detection limit was estimated to be 0.5-1 microg of water using 100ml of reagent in this system.

  15. Coulometric titrations of bases in propylene carbonate and g-butyrolactone using hydroquinone as the depolarizer and a quinhydrone indicator electrode

    Directory of Open Access Journals (Sweden)

    Z. D. STANIC

    2000-08-01

    Full Text Available The application of hydroquinone for the coulometric generation of hydrogen ions in propylene carbonate (PC and g-butyrolactone (GBL is described. The current-potential curves recorded for theid sepolarizer, titrated bases, indicator and the solvents used showed that the investigated depolarizer is oxidized at lower potentials than the oxidation potentials of other components in the solution. the hydrogen ions generated by the oxidation of hydroquinone were used for the titration of organic bases (triethylamine, n-butylamine, pyridine, quinoline, aniline, N,N’-diphenylguanidine, piperidine, and 2,2’-bipiridine in PC and GBL with visual (Crystal Violet as indicator and potentiometric end-point detection using a quinhydrone electrode as the indicator electrode. The quinhydrone added to the to be analyzed solution served both as a source of hydrogen ions and, together with the immersed platinum electrode, as a quinhydrone electrode. The relative error of the determination of the bases was about 1 %.

  16. Nanowire sensors and arrays for chemical/biomolecule detection

    Science.gov (United States)

    Yun, Minhee; Lee, Choonsup; Vasquez, Richard P.; Ramanathan, K.; Bangar, M. A.; Chen, W.; Mulchandan, A.; Myung, N. V.

    2005-01-01

    We report electrochemical growth of single nanowire based sensors using e-beam patterned electrolyte channels, potentially enabling the controlled fabrication of individually addressable high density arrays. The electrodeposition technique results in nanowires with controlled dimensions, positions, alignments, and chemical compositions. Using this technique, we have fabricated single palladium nanowires with diameters ranging between 75 nm and 300 nm and conducting polymer nanowires (polypyrrole and polyaniline) with diameters between 100 nm and 200 nm. Using these single nanowires, we have successfully demonstrated gas sensing with Pd nanowires and pH sensing with polypirrole nanowires.

  17. A bead-based suspension array for the multiplexed detection of begomoviruses and their whitefly vectors.

    Science.gov (United States)

    van Brunschot, S L; Bergervoet, J H W; Pagendam, D E; de Weerdt, M; Geering, A D W; Drenth, A; van der Vlugt, R A A

    2014-03-01

    Bead-based suspension array systems enable simultaneous fluorescence-based identification of multiple nucleic acid targets in a single reaction. This study describes the development of a novel approach to plant virus and vector diagnostics, a multiplexed 7-plex array that comprises a hierarchical set of assays for the simultaneous detection of begomoviruses and Bemisia tabaci, from both plant and whitefly samples. The multiplexed array incorporates genus, species and strain-specific assays, offering a unique approach for identifying both known and unknown viruses and B. tabaci species. When tested against a large panel of sequence-characterized begomovirus and whitefly samples, the array was shown to be 100% specific to the homologous target. Additionally, the multiplexed array was highly sensitive, efficiently and concurrently determining both virus and whitefly identity from single viruliferous whitefly samples. The detection limit for one assay within the multiplexed array that specifically detects Tomato yellow leaf curl virus-Israel (TYLCV-IL) was quantified as 200fg of TYLCV-IL DNA, directly equivalent to that of TYLCV-specific qPCR. Highly reproducible results were obtained over multiple tests. The flexible multiplexed array described in this study has great potential for use in plant quarantine, biosecurity and disease management programs worldwide.

  18. Statistical analysis of DNT detection using chemically functionalized microcantilever arrays

    DEFF Research Database (Denmark)

    Bosco, Filippo; Bache, M.; Hwu, E.-T.

    2012-01-01

    The need for miniaturized and sensitive sensors for explosives detection is increasing in areas such as security and demining. Micrometer sized cantilevers are often used for label-free detection, and have previously been reported to be able to detect explosives. However, only a few measurements...... from 1 to 2 cantilevers have been reported, without any information on repeatability and reliability of the presented data. In explosive detection high reliability is needed and thus a statistical measurement approach needs to be developed and implemented. We have developed a DVD-based read-out system...

  19. Development of recombinant antigen array for simultaneous detection of viral antibodies.

    Directory of Open Access Journals (Sweden)

    Yi Liu

    Full Text Available Protein microarrays have been developed to study antibody reactivity against a large number of antigens, demonstrating extensive perspective for clinical application. We developed a viral antigen array by spotting four recombinant antigens and synthetic peptide, including glycoprotein G of herpes simplex virus (HSV type 1 and 2, phosphoprotein 150 of cytomegalovirus (CMV, Rubella virus (RV core plus glycoprotein E1 and E2 as well as a E1 peptide with the optimal concentrations on activated glass slides to simultaneously detect IgG and IgM against HSV1, HSV2, CMV and RV in clinical specimens of sera and cerebrospinal fluids (CSFs. The positive reference sera were initially used to measure the sensitivity and specificity of the array with the optimal conditions. Then clinical specimens of 144 sera and 93 CSFs were tested for IgG and IgM antibodies directed against HSV1, HSV2, CMV and RV by the antigen array. Specificity of the antigen array for viral antibodies detection was satisfying compared to commercial ELISA kits but sensitivity of the array varied relying on quality and antigenic epitopes of the spotting antigens. In short, the recombinant antigen array has potential to simultaneous detect multiple viral antibodies using minute amount (3 µl of samples, which holds the particularly advantage to detect viral antibodies in clinical CSFs being suspicious of neonatal meningitis and encephalitis.

  20. Detecting changes of a distant gas source with an array of MOX gas sensors.

    Science.gov (United States)

    Pashami, Sepideh; Lilienthal, Achim J; Trincavelli, Marco

    2012-11-27

    We address the problem of detecting changes in the activity of a distant gas source from the response of an array of metal oxide (MOX) gas sensors deployed in an open sampling system. The main challenge is the turbulent nature of gas dispersion and the response dynamics of the sensors. We propose a change point detection approach and evaluate it on individual gas sensors in an experimental setup where a gas source changes in intensity, compound, or mixture ratio. We also introduce an efficient sensor selection algorithm and evaluate the change point detection approach with the selected sensor array subsets.

  1. Enhanced defect detection and sizing accuracy using matrix phased array ultrasonic tools

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Roger; Porter, Nancy; Todorov, Evgueni [Edison Welding Institute (EWI), Columbus, OH (United States); Lozev, Mark [BP, Naperville, IL (United States); Reverdy, Frederic [Centre d' Etudes Nucleaires de Saclay (NDT/CEA) Saclay (France). Nondestructive Testing; Benoist, Philippe [Centre d' Etudes Nucleaires de Saclay (NDE/CEA) Saclay (France); Dumas, Philippe [Imasonic, Besancon (France)

    2009-07-01

    Although ultrasonic testing inspection technology and tools have improved significantly, there is still a need for more reliable detection, monitoring, and accurate sizing of crack-like and planar defects, complex corrosion damage, and detection of secondary features within deformed pipe. Ultrasonic two dimensional (2D) matrix phased array technology offers some unique advantages that make the technology promising for improving detection and sizing of pipeline flaws resulting from welding or from in-service damage. Ultrasonic modeling and simulation has been conducted to evaluate the detection and sizing capabilities of 2D matrix arrays for various pipeline inspection concepts. Simulations have been performed using both flexible and rigid array probes. Inspection concepts using rigid probes were evaluated for inspections from both the outside and inside pipe surfaces, while flexible probes were evaluated primarily for inspection from the outside surface when dents or corrosion damage may limit the use of rigid probes. (author)

  2. Energy detection using very large antenna array receivers

    DEFF Research Database (Denmark)

    Oliveras Martínez, Àlex; De Carvalho, Elisabeth; Popovski, Petar;

    2014-01-01

    We propose the use of energy detection for single stream transmission and reception by a very large number of antennas, with primary application to millimeter wave communications. The reason for applying energy detection is low complexity, cost and power efficiency. While both energy detection...... and millimeter wave communications are limited to short ranges due respectively to noise sensitivity and propagation attenuation, processing by a large number of receive antennas overcomes those shortcomings to provide significant reach extension. This processing is solely based on long-term statistics...

  3. A bead-based suspension array for the serological detection of Trichinella in pigs

    NARCIS (Netherlands)

    Wal, van der F.J.; Achterberg, R.P.; Kant, A.; Maassen, C.B.M.

    2013-01-01

    The feasibility of using bead-based suspension arrays to detect serological evidence of Trichinella in pigs was assessed. Trichinella spiralis excretory–secretory antigen was covalently coupled to paramagnetic beads and used to bind serum antibodies, which were subsequently detected using anti-swine

  4. A Mobile Ferromagnetic Shape Detection Sensor Using a Hall Sensor Array and Magnetic Imaging

    Directory of Open Access Journals (Sweden)

    Nashiren Farzilah Mailah

    2011-11-01

    Full Text Available This paper presents a Mobile Hall Sensor Array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the Mobile Hall Sensor Array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of Mobile Hall Sensor Array system for actual shape detection. The results prove that the Mobile Hall Sensor Array system is able to perform magnetic imaging in identifying various ferromagnetic materials.

  5. A Mobile Ferromagnetic Shape Detection Sensor Using a Hall Sensor Array and Magnetic Imaging

    Science.gov (United States)

    Misron, Norhisam; Shin, Ng Wei; Shafie, Suhaidi; Marhaban, Mohd Hamiruce; Mailah, Nashiren Farzilah

    2011-01-01

    This paper presents a Mobile Hall Sensor Array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the Mobile Hall Sensor Array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of Mobile Hall Sensor Array system for actual shape detection. The results prove that the Mobile Hall Sensor Array system is able to perform magnetic imaging in identifying various ferromagnetic materials. PMID:22346653

  6. A mobile ferromagnetic shape detection sensor using a Hall sensor array and magnetic imaging.

    Science.gov (United States)

    Misron, Norhisam; Shin, Ng Wei; Shafie, Suhaidi; Marhaban, Mohd Hamiruce; Mailah, Nashiren Farzilah

    2011-01-01

    This paper presents a mobile Hall sensor array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the mobile Hall sensor array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of mobile Hall sensor array system for actual shape detection. The results prove that the mobile Hall sensor array system is able to perform magnetic imaging in identifying various ferromagnetic materials.

  7. Fabrication of CdTe quantum dots-apoferritin arrays for detection of dopamine

    Science.gov (United States)

    Le, Thi Hoa; Kim, Ji Hyeon; Park, Sang Joon

    2017-06-01

    A method was proposed for detecting dopamine using a two-dimensional CdTe quantum dots (QDs)-apoferritin array fabricated on a modified silicon (Si) surface. First, CdTe QDs were synthesized in the cavity of horse spleen apoferritin (HsAFr). Then, the characterization of CdTe QDs in apoferritin was performed using photoluminescence (PL) spectroscopy. Transmission electron microscopy was used to analyze the size and structure of CdTe QDs. An atomic force microscopy image was obtained to evaluate the topography of the Si surface. In addition, the PL change resulting from the conjugation reaction of the CdTe QDs-apoferritin array with dopamine was investigated. When the array was linked to dopamine, a significant quenching of fluorescence was observed. Accordingly, the CdTe QDs-apoferritin arrays could be employed as useful sensing media for dopamine detection.

  8. Radio detection of high-energy cosmic rays with the Auger Engineering Radio Array (PISA 2015)

    CERN Document Server

    Schröder, Frank G

    2016-01-01

    The Auger Engineering Radio Array (AERA) is an enhancement of the Pierre Auger Observatory in Argentina. Covering about View the $17\\,$km$^2$, AERA is the world-largest antenna array for cosmic-ray observation. It consists of more than 150 antenna stations detecting the radio signal emitted by air showers, i.e., cascades of secondary particles caused by primary cosmic rays hitting the atmosphere. At the beginning, technical goals had been in focus: first of all, the successful demonstration that a large-scale antenna array consisting of autonomous stations is feasible. Moreover, techniques for calibration of the antennas and time calibration of the array have been developed, as well as special software for the data analysis. Meanwhile physics goals come into focus. At the Pierre Auger Observatory air showers are simultaneously detected by several detector systems, in particular water-Cherenkov detectors at the surface, underground muon detectors, and fluorescence telescopes, which enables cross-calibration of...

  9. Detection of Multiple Waterborne Pathogens Using Microsequencing Arrays

    Science.gov (United States)

    Aims: A microarray was developed to simultaneously detect Cryptosporidium parvum, Cryptosporidium hominis, Enterococcus faecium, Bacillus anthracis and Francisella tularensis in water. Methods and Results: A DNA microarray was designed to contain probes that specifically dete...

  10. Passive acoustic detection of a rebreather using a random array

    NARCIS (Netherlands)

    Fillinger, L.; Hunter, A.J.; Zampolli, M.; Clarijs, M.C.

    2013-01-01

    Divers, including closed circuit (rebreather) divers constitute a potential threat to waterside infrastructures. Active diver detection sonars are available commercially but present some shortcomings, particularly in highly reverberant environments. This has led to research on passive sonar for dive

  11. Passive acoustic detection of a rebreather using a random array

    NARCIS (Netherlands)

    Fillinger, L.; Hunter, A.J.; Zampolli, M.; Clarijs, M.C.

    2013-01-01

    Divers, including closed circuit (rebreather) divers constitute a potential threat to waterside infrastructures. Active diver detection sonars are available commercially but present some shortcomings, particularly in highly reverberant environments. This has led to research on passive sonar for dive

  12. Single molecule detection using charge-coupled device array technology

    Energy Technology Data Exchange (ETDEWEB)

    Denton, M.B.

    1992-07-29

    A technique for the detection of single fluorescent chromophores in a flowing stream is under development. This capability is an integral facet of a rapid DNA sequencing scheme currently being developed by Los Alamos National Laboratory. In previous investigations, the detection sensitivity was limited by the background Raman emission from the water solvent. A detection scheme based on a novel mode of operating a Charge-Coupled Device (CCD) is being developed which should greatly enhance the discrimination between fluorescence from a single molecule and the background Raman scattering from the solvent. Register shifts between rows in the CCD are synchronized with the sample flow velocity so that fluorescence from a single molecule is collected in a single moving charge packet occupying an area approaching that of a single pixel while the background is spread evenly among a large number of pixels. Feasibility calculations indicate that single molecule detection should be achieved with an excellent signal-to-noise ratio.

  13. [Accurate detection of a case with Angelman syndrome (type 1) using SNP array].

    Science.gov (United States)

    Shi, Shanshan; Lin, Shaobin; Liao, Yanfen; Li, Weijing

    2016-12-10

    To analyze a case with Angelman syndrome (AS) using single nucleotide polymorphism array (SNP array) and explore its genotype-phenotype correlation. G-banded karyotyping and SNP array were performed on a child featuring congenital malformations, intellectual disability and developmental delay. Mendelian error checking based on the SNP information was used to delineate the parental origin of detected abnormality. Result of the SNP array was validated with fluorescence in situ hybridization (FISH). The SNP array has detected a 6.053 Mb deletion at 15q11.2q13.1 (22,770,421- 28,823,722) which overlapped with the critical region of AS (type 1). The parents of the child showed no abnormal results for G-banded karyotyping, SNP array and FISH analysis, indicating a de novo origin of the deletion. Mendelian error checking based on the SNP information suggested that the 15q11.2q13.1 deletion was of maternal origin. SNP array can accurately define the size, location and parental origin of chromosomal microdeletions, which may facilitate the diagnosis of AS due to 15q11q13 deletion and better understanding of its genotype-phenotype correlation.

  14. Detection of inflammatory cytokines using a fiber optic microsphere immunoassay array

    Science.gov (United States)

    Blicharz, Timothy M.; Walt, David R.

    2006-10-01

    A multiplexed fiber optic microsphere-based immunoassay array capable of simultaneously measuring five inflammatory cytokines has been developed. Five groups of amine-functionalized 3.1 micron microspheres were internally encoded with five distinct concentrations of a europium dye and converted to cytokine probes by covalently coupling monoclonal capture antibodies specific for human VEGF, IFN-gamma, RANTES, IP-10, and Eotaxin-3 to the microspheres via glutaraldehyde chemistry. The microspheres were pooled and loaded into a 1 mm diameter fiber optic bundle containing ~50,000 individual etched microwells, producing the multiplexed cytokine immunoassay array. Multiple arrays can be created from a single microsphere pool for high throughput sample analysis. Sandwich fluoroimmunoassays were performed by incubating the probe array in a sample, followed by incubation in a mixture of biotin-labeled detection antibodies that are complementary to the five cytokines. Finally, universal detection of each protein was performed using a fluorescence imaging system after briefly immersing the array in a solution of fluorophore-labeled streptavidin. The multiplexed cytokine array has been shown to respond selectively to VEGF, IFNgamma, RANTES, IP-10, and Eotaxin-3, permitting multiplexed quantitative analysis. Ultimately, the multiplexed cytokine array will be utilized to evaluate the potential of using saliva as a noninvasive diagnostic fluid for pulmonary inflammatory diseases such as asthma.

  15. Ultrasonic Array for Obstacle Detection Based on CDMA with Kasami Codes

    Directory of Open Access Journals (Sweden)

    Joaqúın Aparicio

    2011-12-01

    Full Text Available This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA, which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques.

  16. Simulation of Eddy-Current Corrosion Detection Using a Sensor Array

    Science.gov (United States)

    Katyal, V.; Bowler, J. R.

    2003-03-01

    A computer simulation has been developed to evaluate eddy-current probes containing magnetic field sensor arrays for the detection and evaluation of hidden corrosion. The simulation is used to assess probes that incorporate magneto-resistive or Hall devices in a closely-spaced, linear array. These probes will allow rapid data acquisition over a track width determined by the length of the array. The benefit of the simulation is that adjustments to the virtual probe parameters are easily made allowing improvements in sensitivity, imaging capability and resolution. A number of probe designs have been studied in this way including the "racetrack" probe.

  17. Ultrasonic array for obstacle detection based on CDMA with Kasami codes.

    Science.gov (United States)

    Diego, Cristina; Hernández, Alvaro; Jiménez, Ana; Alvarez, Fernando J; Sanz, Rebeca; Aparicio, Joaquín

    2011-01-01

    This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA), which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques.

  18. Patterned Array of Poly(ethylene glycol) Silane Monolayer for Label-Free Detection of Dengue

    OpenAIRE

    Nor Zida Rosly; Shahrul Ainliah Alang Ahmad; Jaafar Abdullah; Nor Azah Yusof

    2016-01-01

    In the present study, the construction of arrays on silicon for naked-eye detection of DNA dengue was demonstrated. The array was created by exposing a polyethylene glycol (PEG) silane monolayer to 254 nm ultraviolet (UV) light through a photomask. Formation of the PEG silane monolayer and photomodifed surface properties was thoroughly characterized by using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results of XPS confirmed that...

  19. Detection of impulsive sources from an aerostat-based acoustic array data collection system

    Science.gov (United States)

    Prather, Wayne E.; Clark, Robert C.; Strickland, Joshua; Frazier, Wm. Garth; Singleton, Jere

    2009-05-01

    An aerostat based acoustic array data collection system was deployed at the NATO TG-53 "Acoustic Detection of Weapon Firing" Joint Field Experiment conducted in Bourges, France during the final two weeks of June 2008. A variety of impulsive sources including mortar, artillery, gunfire, RPG, and explosive devices were fired during the test. Results from the aerostat acoustic array will be presented against the entire range of sources.

  20. Enhancement of concentration range of chromatographically detectable components with array detector mass spectrometry

    Science.gov (United States)

    Enke, Christie

    2013-02-19

    Methods and instruments for high dynamic range analysis of sample components are described. A sample is subjected to time-dependent separation, ionized, and the ions dispersed with a constant integration time across an array of detectors according to the ions m/z values. Each of the detectors in the array has a dynamically adjustable gain or a logarithmic response function, producing an instrument capable of detecting a ratio of responses or 4 or more orders of magnitude.

  1. Detection of clinically relevant exonic copy-number changes by array CGH.

    Science.gov (United States)

    Boone, Philip M; Bacino, Carlos A; Shaw, Chad A; Eng, Patricia A; Hixson, Patricia M; Pursley, Amber N; Kang, Sung-Hae L; Yang, Yaping; Wiszniewska, Joanna; Nowakowska, Beata A; del Gaudio, Daniela; Xia, Zhilian; Simpson-Patel, Gayle; Immken, LaDonna L; Gibson, James B; Tsai, Anne C-H; Bowers, Jennifer A; Reimschisel, Tyler E; Schaaf, Christian P; Potocki, Lorraine; Scaglia, Fernando; Gambin, Tomasz; Sykulski, Maciej; Bartnik, Magdalena; Derwinska, Katarzyna; Wisniowiecka-Kowalnik, Barbara; Lalani, Seema R; Probst, Frank J; Bi, Weimin; Beaudet, Arthur L; Patel, Ankita; Lupski, James R; Cheung, Sau Wai; Stankiewicz, Pawel

    2010-12-01

    Array comparative genomic hybridization (aCGH) is a powerful tool for the molecular elucidation and diagnosis of disorders resulting from genomic copy-number variation (CNV). However, intragenic deletions or duplications--those including genomic intervals of a size smaller than a gene--have remained beyond the detection limit of most clinical aCGH analyses. Increasing array probe number improves genomic resolution, although higher cost may limit implementation, and enhanced detection of benign CNV can confound clinical interpretation. We designed an array with exonic coverage of selected disease and candidate genes and used it clinically to identify losses or gains throughout the genome involving at least one exon and as small as several hundred base pairs in size. In some patients, the detected copy-number change occurs within a gene known to be causative of the observed clinical phenotype, demonstrating the ability of this array to detect clinically relevant CNVs with subkilobase resolution. In summary, we demonstrate the utility of a custom-designed, exon-targeted oligonucleotide array to detect intragenic copy-number changes in patients with various clinical phenotypes.

  2. A fully automatic system for acid-base coulometric titrations

    OpenAIRE

    1990-01-01

    An automatic system for acid-base titrations by electrogeneration of H+ and OH- ions, with potentiometric end-point detection, was developed. The system includes a PC-compatible computer for instrumental control, data acquisition and processing, which allows up to 13 samples to be analysed sequentially with no human intervention. The system performance was tested on the titration of standard solutions, which it carried out with low errors and RSD. It was subsequently applied to the analysis o...

  3. Differential coulometric oxidation following post column-switching high pressure liquid chromatography for fluorescence measurement of unmetabolized folic acid in human plasma.

    Science.gov (United States)

    Bailey, Steven W; Ayling, June E

    2013-11-08

    Although many countries have fortified their grain supplies with folic acid (FA) to decrease the incidence of neural tube defects, others have not due to concerns that this synthetic folate might have some adverse effects. Persistent unmetabolized FA has been found even in plasma from fasted subjects. To facilitate measurement of low levels of folic acid in human plasma, post-column coulometric oxidative cleavage was used to convert poorly fluorescent FA into a highly fluorescent compound determined to be 6-formyl-pterin. To minimize sample work-up and maximize recovery, column-switching HPLC transferred a window of eluate containing the FA from the first column (C8) onto a second column (phenyl-hexyl). The pH of two mobile phases were adjusted to be above and then below a pK of the FA α-carboxyl group, thus promoting separation from compounds coeluting from the C8-column. This permitted sample preparation using only a simple high recovery protein precipitation. Definitive identification of FA in human plasma was accomplished by duplicate injections of sample with the electrochemical voltage set above and below its half-potential. The LOD (S/N=3) was 0.10 nM. The intra- and inter-assay CV's were 2.3% and 5%, respectively. Comparison of these results with those obtained by HPLC/MS/MS with stable isotope internal standard showed a slope of 1.00 ± 0.019. This simple, sensitive, and repeatable assay facilitates a more thorough investigation of the response of various human populations to folic acid intake. Post-column differential coulometric electrochemistry can expand the variety of compounds amenable to fluorescence detection.

  4. Coulometric-potentiometric determination of autoprotolysis constant and relative acidity scale of water

    Directory of Open Access Journals (Sweden)

    Džudović Radmila M.

    2010-01-01

    Full Text Available The autoprotolysis constant and relative acidity scale of water were determined by applying the coulometric-potentiometric method and a hydrogen/palladium (H2/Pd generator anode. In the described procedure for the evaluation of autoprotolysis constant, a strong base generated coulometrically at the platinum cathode in situ in the electrolytic cell, in presence of sodium perchlorate as the supporting electrolyte, is titrated with hydrogen ions obtained by the anodic oxidation of hydrogen dissolved in palladium electrode. The titration was carried out with a glass-SCE electrode pair at 25.0±0.1°C. The value obtained pKw = 13.91 ± 0.06 is in agreement with literature data. The range of acidity scale of water is determined from the difference between the halfneutralization potentials of electrogenerated perchloric acid and that of sodium hydroxide in a sodium perchlorate medium. The halfneutralization potentials were measured using both a glass-SCE and a (H2/Pdind-SCE electrode pairs. A wider range of relative acidity scale of water was obtained with the glass-SCE electrode pair.

  5. Standoff photoacoustic detections with high-sensitivity microphones and acoustic arrays

    Science.gov (United States)

    Choa, Fow-Sen; Wang, Chen-Chia; Khurgin, Jacob; Samuels, Alan; Trivedi, Sudhir; Gupta, Deepa

    2016-05-01

    Standoff detection of dangerous chemicals like explosives, nerve gases, and harmful aerosols has continuously been an important subject due to the serious concern about terrorist threats to both overseas and homeland lives and facility. Compared with other currently available standoff optical detection techniques, like Raman, photo-thermal, laser induced breakdown spectroscopy,...etc., photoacoustic (PA) sensing has the advantages of background free and very high detection sensitivity, no need of back reflection surfaces, and 1/R instead of 1/R2 signal decay distance dependence. Furthermore, there is still a great room for PA sensitivity improvement by using different PA techniques, including lockin amplifier, employing new microphones, and microphone array techniques. Recently, we have demonstrated standoff PA detection of isopropanol vapor, solid phase TNT and RDX at a standoff distance. To further calibrate the detection sensitivity, we use nerve gas simulants that were generated and calibrated by a commercial vapor generator. For field operations, array of microphones and microphone-reflector pairs can be utilized to achieve noise rejection and signal enhancement. We have experimentally demonstrated signal enhancement and noise reduction using an array of 4 microphone/4 reflector system as well as an array of 16-microphone/1 reflector. In this work we will review and compare different standoff techniques and discuss the advantages of using different photoacoustic techniques. We will also discuss new advancement of using new types of microphone and the performance comparison of using different structure of microphone arrays and combining lock-in amplifier with acoustic arrays. Demonstration of out-door real-time operations with high power mid-IR laser and microphone array will be presented.

  6. Laser tailored nanoparticle arrays to detect molecules at dilute concentration

    Science.gov (United States)

    Zanchi, Chiara; Lucotti, Andrea; Tommasini, Matteo; Trusso, Sebastiano; de Grazia, Ugo; Ciusani, Emilio; Ossi, Paolo M.

    2017-02-01

    By nanosecond pulsed laser ablation in an ambient gas gold nanoparticles (NPs) were produced that self-assemble on a substrate resulting in increasingly elaborated architectures of growing thickness, from isolated NP arrays up to percolated films. NPs nucleate and grow in the plasma plume propagating through the gas. Process parameters including laser wavelength, laser energy density, target to substrate distance, nature and pressure of the gas affect plasma expansion, thus asymptotic NP size and kinetic energy. NP size, energy and mobility at landing determine film growth and morphology that affect the physico-chemical properties of the film. Keeping fixed the other process parameters, we discuss the sensitive dependence of film surface nanostructure on Ar pressure and on laser pulse number. The initial plume velocity and average ablated mass per pulse allow predicting the asymptotic NP size. The control of growth parameters favors fine-tuning of NP aggregation, relevant to plasmonics to get optimized substrates for surface enhanced Raman spectroscopy (SERS). Their behavior is discussed for testing conditions of interest for clinical application. Both in aqueous and in biological solutions we obtained good sensitivity and reproducibility of the SERS signals for the anti-Parkinson drug apomorphine, and for the anti-epilepsy drug carbamazepine.

  7. Fault detection, isolation, and diagnosis of status self-validating gas sensor arrays.

    Science.gov (United States)

    Chen, Yin-Sheng; Xu, Yong-Hui; Yang, Jing-Li; Shi, Zhen; Jiang, Shou-da; Wang, Qi

    2016-04-01

    The traditional gas sensor array has been viewed as a simple apparatus for information acquisition in chemosensory systems. Gas sensor arrays frequently undergo impairments in the form of sensor failures that cause significant deterioration of the performance of previously trained pattern recognition models. Reliability monitoring of gas sensor arrays is a challenging and critical issue in the chemosensory system. Because of its importance, we design and implement a status self-validating gas sensor array prototype to enhance the reliability of its measurements. A novel fault detection, isolation, and diagnosis (FDID) strategy is presented in this paper. The principal component analysis-based multivariate statistical process monitoring model can effectively perform fault detection by using the squared prediction error statistic and can locate the faulty sensor in the gas sensor array by using the variables contribution plot. The signal features of gas sensor arrays for different fault modes are extracted by using ensemble empirical mode decomposition (EEMD) coupled with sample entropy (SampEn). The EEMD is applied to adaptively decompose the original gas sensor signals into a finite number of intrinsic mode functions (IMFs) and a residual. The SampEn values of each IMF and the residual are calculated to reveal the multi-scale intrinsic characteristics of the faulty sensor signals. Sparse representation-based classification is introduced to identify the sensor fault type for the purpose of diagnosing deterioration in the gas sensor array. The performance of the proposed strategy is compared with other different diagnostic approaches, and it is fully evaluated in a real status self-validating gas sensor array experimental system. The experimental results demonstrate that the proposed strategy provides an excellent solution to the FDID of status self-validating gas sensor arrays.

  8. Development of Diamond and Silicon MEMS Sensor Arrays with Integrated Readout for Vapor Detection

    Science.gov (United States)

    Possas-Abreu, Maira; Ghassemi, Farbod; Rousseau, Lionel; Scorsone, Emmanuel; Descours, Emilie; Lissorgues, Gaelle

    2017-01-01

    This paper reports on the development of an autonomous instrument based on an array of eight resonant microcantilevers for vapor detection. The fabricated sensors are label-free devices, allowing chemical and biological functionalization. In this work, sensors based on an array of silicon and synthetic diamond microcantilevers are sensitized with polymeric films for the detection of analytes. The main advantage of the proposed system is that sensors can be easily changed for another application or for cleaning since the developed gas cell presents removable electrical connections. We report the successful application of our electronic nose approach to detect 12 volatile organic compounds. Moreover, the response pattern of the cantilever arrays is interpreted via principal component analysis (PCA) techniques in order to identify samples. PMID:28538653

  9. Vertical nanowire arrays as a versatile platform for protein detection and analysis

    DEFF Research Database (Denmark)

    Rostgaard, Katrine R.; Frederiksen, Rune S.; Liu, Yi-Chi;

    2013-01-01

    Protein microarrays are valuable tools for protein assays. Reducing spot sizes from micro- to nano-scale facilitates miniaturization of platforms and consequently decreased material consumption, but faces inherent challenges in the reduction of fluorescent signals and compatibility with complex...... the NWs unnecessary. Fluorescence detection of proteins allows quantitative measurements and spatial resolution, enabling us to track individual NWs through several analytical steps, thereby allowing multiplexed detection of different proteins immobilized on different regions of the NW array. We use NW...... arrays for on-chip extraction, detection and functional analysis of proteins on a nano-scale platform that holds great promise for performing protein analysis on minute amounts of material. The demonstration made here on highly ordered arrays of indium arsenide (InAs) NWs is generic and can be extended...

  10. High-sensitivity high-throughput chip based biosensor array for multiplexed detection of heavy metals

    Science.gov (United States)

    Yan, Hai; Tang, Naimei; Jairo, Grace A.; Chakravarty, Swapnajit; Blake, Diane A.; Chen, Ray T.

    2016-03-01

    Heavy metal ions released into the environment from industrial processes lead to various health hazards. We propose an on-chip label-free detection approach that allows high-sensitivity and high-throughput detection of heavy metals. The sensing device consists of 2-dimensional photonic crystal microcavities that are combined by multimode interferometer to form a sensor array. We experimentally demonstrate the detection of cadmium-chelate conjugate with concentration as low as 5 parts-per-billion (ppb).

  11. Graphene quantum dots modified silicon nanowire array for ultrasensitive detection in the gas phase

    Science.gov (United States)

    Li, T. Y.; Duan, C. Y.; Zhu, Y. X.; Chen, Y. F.; Wang, Y.

    2017-03-01

    Si nanostructure-based gas detectors have attracted much attention due to their huge surface areas, relatively high carrier mobility, maneuverability for surface functionalization and compatibility to modern electronic industry. However, the unstable surface of Si, especially for the nanostructures in a corrosive atmosphere, hinders their sensitivity and reproducibility when used for detection in the gas phase. In this study, we proposed a novel strategy to fabricate a Si-based gas detector by using the vertically aligned Si nanowire (SiNW) array as a skeleton and platform, and decorated chemically inert graphene quantum dots (GQDs) to protect the SiNWs from oxidation and promote the carriers’ interaction with the analytes. The radial core–shell structures of the GQDs/SiNW array were then assembled into a resistor-based gas detection system and evaluated by using nitrogen dioxide (NO2) as the model analyte. Compared to the bare SiNW array, our novel sensor exhibited ultrahigh sensitivity for detecting trace amounts of NO2 with the concentration as low as 10 ppm in room temperature and an immensely reduced recovery time, which is of significant importance for their practical application. Meanwhile, strikingly, reproducibility and stability could also be achieved by showing no sensitivity decline after storing the GQDs/SiNW array in air for two weeks. Our results demonstrate that protecting the surface of the SiNW array with chemically inert GQDs is a feasible strategy to realize ultrasensitive detection in the gas phase.

  12. Modelling of coulometric sensor-actuator systems based on ISFETs with a porous actuator covering the gate

    NARCIS (Netherlands)

    Luo, J.; Olthuis, W.; Bergveld, P.; Bos, M.; Linden, van der W.E.

    1993-01-01

    The ion-selective field effect transistor (ISFET)-based coulometric sensor¿actuator systems have found applications in acid¿base titration and in the construction of a low-drift carbon dioxide and a pH-static enzyme sensor. In this paper a brief review is given of the previously developed ISFET-base

  13. Simplified design of the coulometric sensor-actuator system by the application of a time-dependent actuator current

    NARCIS (Netherlands)

    Olthuis, W.; Bergveld, P.

    1992-01-01

    Acid or base concentrations can be determined by performing an acid-base titration with coulometrically generated OH¿ or H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. It is shown, both theoretically and experimentally, that the relation between

  14. Modelling of non-steady-state concentration profiles at ISFET-based coulometric sensor—actuator systems

    NARCIS (Netherlands)

    Olthuis, W.; Luo, J.; Schoot, van der B.H.; Bergveld, P.; Bos, M.; Linden, van der W.E.

    1990-01-01

    Acid or base concentrations can be determined very rapidly by performing an acid—base titration with coulometrically generated OH− or H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ion-sensitive field effect transistor (ISFET). The ISFET is used as the

  15. Simplified design of the coulometric sensor-actuator system by the application of a time-dependent actuator current

    NARCIS (Netherlands)

    Olthuis, Wouter; Bergveld, Piet

    1992-01-01

    Acid or base concentrations can be determined by performing an acid-base titration with coulometrically generated OH¿ or H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. It is shown, both theoretically and experimentally, that the relation between

  16. Study on data acquisition circuit used in SSPA linear array detector X-ray detection

    CERN Document Server

    Wei Biao; Che Zhen Ping

    2002-01-01

    After SSPA used as X-ray array detector is developed, the authors take a research on the data acquisition circuit applied to the detector. The experiment designed has verified the feasibility of application of this array detector and its data acquisition circuit to X-ray computed tomography (X-CT). The preliminary test results indicate that the method of the X-ray detection is feasible for industry X-CT nondestructive testing, which brings about advantage for detecting and measuring with high resolution, good efficiency and low cost

  17. High taxonomic level fingerprint of the human intestinal microbiota by Ligase Detection Reaction - Universal Array approach

    Directory of Open Access Journals (Sweden)

    Vitali Beatrice

    2010-04-01

    Full Text Available Abstract Background Affecting the core functional microbiome, peculiar high level taxonomic unbalances of the human intestinal microbiota have been recently associated with specific diseases, such as obesity, inflammatory bowel diseases, and intestinal inflammation. Results In order to specifically monitor microbiota unbalances that impact human physiology, here we develop and validate an original DNA-microarray (HTF-Microbi.Array for the high taxonomic level fingerprint of the human intestinal microbiota. Based on the Ligase Detection Reaction-Universal Array (LDR-UA approach, the HTF-Microbi.Array enables specific detection and approximate relative quantification of 16S rRNAs from 30 phylogenetically related groups of the human intestinal microbiota. The HTF-Microbi.Array was used in a pilot study of the faecal microbiota of eight young adults. Cluster analysis revealed the good reproducibility of the high level taxonomic microbiota fingerprint obtained for each of the subject. Conclusion The HTF-Microbi.Array is a fast and sensitive tool for the high taxonomic level fingerprint of the human intestinal microbiota in terms of presence/absence of the principal groups. Moreover, analysis of the relative fluorescence intensity for each probe pair of our LDR-UA platform can provide estimation of the relative abundance of the microbial target groups within each samples. Focusing the phylogenetic resolution at division, order and cluster levels, the HTF-Microbi.Array is blind with respect to the inter-individual variability at the species level.

  18. Optical antenna arrays on a fiber facet for in situ surface-enhanced Raman scattering detection.

    Science.gov (United States)

    Smythe, Elizabeth J; Dickey, Michael D; Bao, Jiming; Whitesides, George M; Capasso, Federico

    2009-03-01

    This paper reports a bidirectional fiber optic probe for the detection of surface-enhanced Raman scattering (SERS). One facet of the probe features an array of gold optical antennas designed to enhance Raman signals, while the other facet of the fiber is used for the input and collection of light. Simultaneous detection of benzenethiol and 2-[(E)-2-pyridin-4-ylethenyl]pyridine is demonstrated through a 35 cm long fiber. The array of nanoscale optical antennas was first defined by electron-beam lithography on a silicon wafer. The array was subsequently stripped from the wafer and then transferred to the facet of a fiber. Lithographic definition of the antennas provides a method for producing two-dimensional arrays with well-defined geometry, which allows (i) the optical response of the probe to be tuned and (ii) the density of "hot spots" generating the enhanced Raman signal to be controlled. It is difficult to determine the Raman signal enhancement factor (EF) of most fiber optic Raman sensors featuring hot spots because the geometry of the Raman enhancing nanostructures is poorly defined. The ability to control the size and spacing of the antennas enables the EF of the transferred array to be estimated. EF values estimated after focusing a laser directly onto the transferred array ranged from 2.6 x 10(5) to 5.1 x 10(5).

  19. Applications of Flexible Ultrasonic Transducer Array for Defect Detection at 150 °C

    Directory of Open Access Journals (Sweden)

    Jiunn-Woei Liaw

    2013-01-01

    Full Text Available In this study, the feasibility of using a one dimensional 16-element flexible ultrasonic transducer (FUT array for nondestructive testing at 150 °C is demonstrated. The FUT arrays were made by a sol-gel sprayed piezoelectric film technology; a PZT composite film was sprayed on a titanium foil of 75 µm thickness. Since the FUT array is flexible, it was attached to a steel pipe with an outer diameter of 89 mm and a wall thickness of 6.5 mm at 150 °C. Using the ultrasonic pulse-echo mode, pipe thickness measurements could be performed. Moreover, using the ultrasonic pulse-echo and pitch-catch modes of each element of FUT array, the defect detection was performed on an Al alloy block of 30 mm thickness with a side-drilled hole (SDH of f3 mm at 150 °C. In addition, a post-processing algorithm based on the total focusing method was used to process the full matrix of these A-scan signals of each single transmitter and multi-receivers, and then the phase-array image was obtained to indicate this defect- SDH. Both results show the capability of FUT array being operated at 150 °C for the corrosion and defect detections.

  20. An arrayed accelerometer device of a wide range of detection for integrated CMOS-MEMS technology

    Science.gov (United States)

    Konishi, Toshifumi; Yamane, Daisuke; Matsushima, Takaaki; Masu, Kazuya; Machida, Katsuyuki; Toshiyoshi, Hiroshi

    2014-02-01

    This paper reports the design and experimental results of an arrayed accelerometer device in 3 × 3 format that can detect wide range of acceleration between 1G and 20G (1G = 9.8 m/s2). Implemented in a single chip has been performed by gold electroplating for integrated complementary metal oxide semiconductor-microelectromechanical systems (CMOS-MEMS) technology. An equivalent circuit of a MEMS accelerometer has been developed with an electrical circuit simulator to demonstrate the mixed-behavior of the arrayed sensor device and sensing CMOS circuits. Mechanical and electrical crosstalk between the arrayed elements is analyzed on the electrical field distributions. Experimental results show that the resonant frequency and readout capacitance as a function of applied acceleration have been well explained by the results of the multi-physics simulation. As a result, it is confirmed that the proposed device is applicable to an integrated CMOS-MEMS arrayed accelerometer.

  1. Spatiotemporal and geometric optimization of sensor arrays for detecting analytes in fluids

    Science.gov (United States)

    Lewis, Nathan S [La Canada, CA; Freund, Michael S [Winnipeg, CA; Briglin, Shawn S [Chittenango, NY; Tokumaru, Phillip [Moorpark, CA; Martin, Charles R [Gainesville, FL; Mitchell, David [Newtown, PA

    2009-09-29

    Sensor arrays and sensor array systems for detecting analytes in fluids. Sensors configured to generate a response upon introduction of a fluid containing one or more analytes can be located on one or more surfaces relative to one or more fluid channels in an array. Fluid channels can take the form of pores or holes in a substrate material. Fluid channels can be formed between one or more substrate plates. Sensor can be fabricated with substantially optimized sensor volumes to generate a response having a substantially maximized signal to noise ratio upon introduction of a fluid containing one or more target analytes. Methods of fabricating and using such sensor arrays and systems are also disclosed.

  2. Spatiotemporal and geometric optimization of sensor arrays for detecting analytes in fluids

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Nathan S. (La Canada, CA); Freund, Michael S. (Winnipeg, CA); Briglin, Shawn S. (Chittenango, NY); Tokumaru, Phillip (Moorpark, CA); Martin, Charles R. (Gainesville, FL); Mitchell, David (Newtown, PA)

    2009-09-29

    Sensor arrays and sensor array systems for detecting analytes in fluids. Sensors configured to generate a response upon introduction of a fluid containing one or more analytes can be located on one or more surfaces relative to one or more fluid channels in an array. Fluid channels can take the form of pores or holes in a substrate material. Fluid channels can be formed between one or more substrate plates. Sensor can be fabricated with substantially optimized sensor volumes to generate a response having a substantially maximized signal to noise ratio upon introduction of a fluid containing one or more target analytes. Methods of fabricating and using such sensor arrays and systems are also disclosed.

  3. INDRA, a 4{pi} charged product detection array at GANIL

    Energy Technology Data Exchange (ETDEWEB)

    Pouthas, J.; Plagnol, E.; Saint-Laurent, F.; Auger, G.; Benkirane, A.; Benlliure, J.; Bourgault, P.; Chbihi, A.; Clerc, T.; Copinet, N.; Huguet, Y.; Le Guay, M.; Martina, L.; Olivier, L.; Piquet, B.; Raine, B.; Ropert, J.; Spitaels, C.; Tripon, M.; Vallerand, P.; Wieleczko, J.P.; Wittwer, G. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Borderie, B.; Rivet, M.F.; Bacri, C.O.; Barbey, S.; Barbier, A.; Box, P.; Bzyl, R.; Charlet, D.; Engrand, M.; Lelong, P.; Pierre, S.; Richard, A.; Stab, L.; Sznajderman, D.; Tassan-Got, L.; Volkov, P. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Dayras, R.; Berthier, B.; Bougamont, E.; Cahan, B.; Cassagnou, Y.; Charvet, J.L.; Legrain, R.; Mazur, C.; Passerieux, J.P.; Pollacco, E.C.; Volant, C. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Steckmeyer, J.C.; Cussol, D.; Gautier, J.M.; Laville, J.L.; Le Botlan, P.; Leconte, A.; Mosrin, P.; Tillier, J. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Jouniaux, O.; Plaige, E. [Paris-11 Univ., 91 - Orsay (France). Lab. de l`Accelerateur Lineaire

    1994-12-31

    INDRA, a new and innovative highly segmented detector for light charged particles and fragments is described. It covers geometrically 90% of the 4{pi} solid angle and has very low detection thresholds. The detector, operated under vacuum, is axially symmetric and segmented in 336 independent cells allowing efficient detection of high multiplicity events. Nucleus identification down to very low energy threshold ({approx_equal} 1 A.MeV) is achieved by using ionization chambers operated with low pressure C{sub 3}F{sub 8} gas. Residual energies are measured by a combination of silicon (300 {mu}m thick) and cesium iodide (5 to 14 cm in length) detectors. Very forward angles are covered by fast counting phoswich scintillators (NE102/NE115). Charge resolution up to Z=50 is achieved on a large energy dynamic range (5000 to 1 for silicon detectors). Isotopic separation is obtained up to Z=3. The treatment of the signals is performed through specifically designed and highly integrated modules, most of which are in the new VXIbus standard. Full remote control of parameter settings, including visualization of signals, is thus allowed. The detector is continuously monitored with a laser source and electronic pulsers and is found stable over several days. Energy calibration procedures, making use of specific detectors and the ability of the GANIL accelerator to deliver secondary beams, have been developed. First experiments were performed in the spring of 1993. (authors). 49 refs., 25 figs., 3 tabs.

  4. INDRA, a 4{pi} charged product detection array at GANIL

    Energy Technology Data Exchange (ETDEWEB)

    Pouthas, J.; Plagnol, E.; Saint-Laurent, F.; Auger, G.; Benkirane, A.; Benlliure, J.; Bourgault, P.; Chbihi, A.; Clerc, T.; Copinet, N.; Huguet, Y.; Le Guay, M.; Martina, L.; Olivier, L.; Piquet, B.; Raine, B.; Ropert, J.; Spitaels, C.; Tripon, M.; Vallerand, P.; Wieleczko, J.P.; Wittwer, G. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Borderie, B.; Rivet, M.F.; Bacri, C.O.; Barbey, S.; Barbier, A.; Box, P.; Bzyl, R.; Charlet, D.; Engrand, M.; Lelong, P.; Pierre, S.; Richard, A.; Stab, L.; Sznajderman, D.; Tassan-Got, L.; Volkov, P. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Dayras, R.; Berthier, B.; Bougamont, E.; Cahan, B.; Cassagnou, Y.; Charvet, J.L.; Legrain, R.; Mazur, C.; Passerieux, J.P.; Pollacco, E.C.; Volant, C. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Steckmeyer, J.C.; Cussol, D.; Gautier, J.M.; Laville, J.L.; Le Botlan, P.; Leconte, A.; Mosrin, P.; Tillier, J. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Jouniaux, O.; Plaige, E. [Paris-11 Univ., 91 - Orsay (France). Lab. de l`Accelerateur Lineaire

    1994-12-31

    INDRA, a new and innovative highly segmented detector for light charged particles and fragments is described. It covers geometrically 90% of the 4{pi} solid angle and has very low detection thresholds. The detector, operated under vacuum, is axially symmetric and segmented in 336 independent cells allowing efficient detection of high multiplicity events. Nucleus identification down to very low energy threshold ({approx_equal} 1 A.MeV) is achieved by using ionization chambers operated with low pressure C{sub 3}F{sub 8} gas. Residual energies are measured by a combination of silicon (300 {mu}m thick) and cesium iodide (5 to 14 cm in length) detectors. Very forward angles are covered by fast counting phoswich scintillators (NE102/NE115). Charge resolution up to Z=50 is achieved on a large energy dynamic range (5000 to 1 for silicon detectors). Isotopic separation is obtained up to Z=3. The treatment of the signals is performed through specifically designed and highly integrated modules, most of which are in the new VXIbus standard. Full remote control of parameter settings, including visualization of signals, is thus allowed. The detector is continuously monitored with a laser source and electronic pulsers and is found stable over several days. Energy calibration procedures, making use of specific detectors and the ability of the GANIL accelerator to deliver secondary beams, have been developed. First experiments were performed in the spring of 1993. (authors). 49 refs., 25 figs., 3 tabs.

  5. Patterned Array of Poly(ethylene glycol Silane Monolayer for Label-Free Detection of Dengue

    Directory of Open Access Journals (Sweden)

    Nor Zida Rosly

    2016-08-01

    Full Text Available In the present study, the construction of arrays on silicon for naked-eye detection of DNA dengue was demonstrated. The array was created by exposing a polyethylene glycol (PEG silane monolayer to 254 nm ultraviolet (UV light through a photomask. Formation of the PEG silane monolayer and photomodifed surface properties was thoroughly characterized by using atomic force microscopy (AFM, X-ray photoelectron spectroscopy (XPS, and contact angle measurements. The results of XPS confirmed that irradiation of ultraviolet (UV light generates an aldehyde functional group that offers conjugation sites of amino DNA probe for detection of a specific dengue virus target DNA. Employing a gold enhancement process after inducing the electrostatic interaction between positively charged gold nanoparticles and the negatively charged target DNA hybridized to the DNA capture probe allowed to visualize the array with naked eye. The developed arrays demonstrated excellent performance in diagnosis of dengue with a detection limit as low as 10 pM. The selectivity of DNA arrays was also examined using a single base mismatch and noncomplementary target DNA.

  6. Radio detection of high-energy cosmic rays with the Auger Engineering Radio Array

    Science.gov (United States)

    Schröder, Frank G.

    2016-07-01

    The Auger Engineering Radio Array (AERA) is an enhancement of the Pierre Auger Observatory in Argentina. Covering about 17km2, AERA is the world-largest antenna array for cosmic-ray observation. It consists of more than 150 antenna stations detecting the radio signal emitted by air showers, i.e., cascades of secondary particles caused by primary cosmic rays hitting the atmosphere. At the beginning, technical goals had been in focus: first of all, the successful demonstration that a large-scale antenna array consisting of autonomous stations is feasible. Moreover, techniques for calibration of the antennas and time calibration of the array have been developed, as well as special software for the data analysis. Meanwhile physics goals come into focus. At the Pierre Auger Observatory air showers are simultaneously detected by several detector systems, in particular water-Cherenkov detectors at the surface, underground muon detectors, and fluorescence telescopes, which enables cross-calibration of different detection techniques. For the direction and energy of air showers, the precision achieved by AERA is already competitive; for the type of primary particle, several methods are tested and optimized. By combining AERA with the particle detectors we aim for a better understanding of cosmic rays in the energy range from approximately 0.3 to 10 EeV, i.e., significantly higher energies than preceding radio arrays.

  7. Using Seismic Arrays to Detect Triggered and Ambient Tremor in Taiwan

    Science.gov (United States)

    Sun, W.; Peng, Z.; Lin, C.; Chao, K.

    2013-12-01

    Deep tectonic tremor triggered by teleseismic surface waves have been recently observed in the southern Central Range in Taiwan, an arc-continental type collision environment. Aiming to capture more tremor events, we installed two dense 36-element, small-aperture seismic arrays in 2011 around the Liouguei and Lidao areas, which are located about 20 km in southwest and northeast to the tremor sources. In each array, short-period, vertical-channel GS-11D sensors with 4.5Hz natural frequency seismometers were laid out on the relatively flat parts of the mountain areas with a spacing of approximately 100 by 80 meters. We had successfully recorded continuously for a total of 4,034 hours in 2011. As expected, the two arrays recorded tremor bursts triggered by the great Tohoku earthquake (Mw=9.0) on March 11, 2011. We apply the broadband frequency wavenumber (BBFK) beamforming method to measure the back-azimuth and incident angles for each tremor burst and through the whole data set. Our initial results show that obtained array parameters closely match those predicted from locations using tremor envelope cross-correlations (WECC) and we detect more tremor duration by BBFK than WECC. We further use a moving-window grid-search (MWGS) method to detect regular earthquakes. Our result indicates the southwestern array provides more stable results than the northeastern array. Our next step is to apply the same MWGS procedure to detect ambient tremor recorded by the southwestern array. Our systematic analysis of deep tremor in Taiwan could help to better understand critical conditions related to tremor occurrence and fault mechanics at the bottom of the seismogenic layer.

  8. TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2.

    Science.gov (United States)

    Zhang, Xiaoxing; Zhang, Jinbin; Jia, Yichao; Xiao, Peng; Tang, Ju

    2012-01-01

    The detection of partial discharge through analysis of SF(6) gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO(2) nanotube array sensor for detecting the SF(6) decomposition product SO(2), and the application of the anodic oxidation method for the directional growth of highly ordered TiO(2) nanotube arrays. The sensor response of 10-50 ppm SO(2) gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO(2) nanotube sensor array has good response to SO(2) gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components.

  9. TiO2 Nanotube Array Sensor for Detecting the SF6 Decomposition Product SO2

    Directory of Open Access Journals (Sweden)

    Ju Tang

    2012-03-01

    Full Text Available The detection of partial discharge through analysis of SF6 gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2, and the application of the anodic oxidation method for the directional growth of highly ordered TiO2 nanotube arrays. The sensor response of 10–50 ppm SO2 gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO2 nanotube sensor array has good response to SO2 gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components.

  10. Gene chip array for differentiation of mycobacterial species and detection of drug resistance

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-chun; LIU Xiao-qing; XIE Xiu-li; XU Ying-chun; ZHAO Zhi-xian

    2012-01-01

    Background Gene chip array can differentiate isolated mycobacterial strains using vadous mycobacterium specific probes simultaneously.Gene chip array can evaluate drug resistance to isoniazid and rifampin of tuberculosis strains by detecting drug resistance related gene mutation.This technique has great potential for clinical application.We performed a retrospective study to investigate the capability of gene chip array in the rapid differentiation of species and detection of drug resistance in mycobacterium,and to evaluate its clinical efficacy.Methods We selected 39 patients (54 clinical mycobacterium isolates),used gene chip array to identify the species of these isolates and detect drug resistance to isoniazid and rifampin in Mycobacterium tuberculosis isolates.Meanwhile,these patients' clinical data were analyzed retrospectively.Results Among these 39 patients whose mycopacterium culture were positive,32 patients' isolates were identified as Mycobacterium tubercu/osis, all of them were clinical infection. Seven patients' isolates were identified as non-tuberculosis mycobacterium.Analyzed with their clinical data,only two patients were considered as clinical infection,both of them were diagnosed as hematogenous disseminated Mycobacterium introcellulare infection.The other five patients' isolates were of no clinical significance; their clinical samples were all respiratory specimens.Clinical manifestations of tuberculosis and non-tuberculous mycobacterial infections were similar.Isoniazid resistance was detected in two tuberculosis patients,while rifampin resistance was detected in one tuberculosis patient; there was another patient whose Mycobacterium tuberculosis isolate was resistant to both isoniazid and rifampin (belongs to multidrug resistance tuberculosis).The fact that this patient did not respond to routine anti-tuberculosis chemotherapy also confirmed this result.Conclusions Gene chip array may be a simple,rapid,and reliable method for the

  11. Nanowatt chemical vapor detection with a self-sensing, piezoelectric microcantilever array

    Science.gov (United States)

    Adams, J. D.; Parrott, G.; Bauer, C.; Sant, T.; Manning, L.; Jones, M.; Rogers, B.; McCorkle, D.; Ferrell, T. L.

    2003-10-01

    The portability, compactness, price, and deployment of sensing systems are determined in large part by the power consumption and simplicity of the sensing platform used. We demonstrate a microcantilever chemical detection platform based on an array of piezoelectric microcantilevers. The sensor-element array power consumption, including actuation, is measured in nanowatts, with impedance of the order of megohms. This is four to five orders of magnitude lower power dissipation than current cantilever chemical detection platforms using optical or piezoresistive detection. The sensor is further characterized in the picowatt regime. The platform comprises three cantilevers wired in series, where variations in the resonant frequency and quality factor of selectively coated cantilevers, during successive impedance measurements, enable detection of ethanol vapor.

  12. High reproducibility and sensitivity of bifacial copper nanowire array for detection of glucose

    Directory of Open Access Journals (Sweden)

    Hanqing Zhang

    2017-06-01

    Full Text Available The ordered bifacial copper nanowire array (Cu BNWA was synthesized by a template assisted electrochemical deposition method. The morphology and structure of the as-prepared samples were investigated by field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. The results show that the ordered Cu nanowire array with uniform geometrical dimensions covered both side of the Cu substrate. When used as the electrode for glucose detection, the minimum detectable concentration of glucose can be reached as low as 0.2 mM. Impressively, the sample still showed high sensitivity and stability for glucose detection after two months placement in ambient environment. These excellent performances of the Cu BNWA make it a promising non-enzyme glucose detection sensor for various applications.

  13. Multi-focus parallel detection of fluorescent molecules at picomolar concentration with photonic nanojets arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ghenuche, Petru; Torres, Juan de; Ferrand, Patrick; Wenger, Jérôme, E-mail: jerome.wenger@fresnel.fr [CNRS, Aix Marseille Université, Ecole Centrale Marseille, Institut Fresnel UMR7249, 13013 Marseille (France)

    2014-09-29

    Fluorescence sensing and fluorescence correlation spectroscopy (FCS) are powerful methods to detect and characterize single molecules; yet, their use has been restricted by expensive and complex optical apparatus. Here, we present a simple integrated design using a self-assembled bi-dimensional array of microspheres to realize multi-focus parallel detection scheme for FCS. We simultaneously illuminate and collect the fluorescence from several tens of microspheres, which all generate their own photonic nanojet to efficiently excite the molecules and collect the fluorescence emission. Each photonic nanojet contributes to the global detection volume, reaching FCS detection volumes of several tens of femtoliters while preserving the fluorescence excitation and collection efficiencies. The microspheres photonic nanojets array enables FCS experiments at low picomolar concentrations with a drastic reduction in apparatus cost and alignment constraints, ideal for microfluidic chip integration.

  14. Expected properties of the first gravitational wave signal detected with pulsar timing arrays

    CERN Document Server

    Rosado, Pablo A; Gair, Jonathan

    2015-01-01

    In this paper we attempt to investigate the nature of the first gravitational wave (GW) signal to be detected by pulsar timing arrays (PTAs): will it be an individual, resolved supermassive black hole binary (SBHB), or a stochastic background made by the superposition of GWs produced by an ensemble of SBHBs? To address this issue, we analyse a broad set of simulations of the cosmological population of SBHBs, that cover the entire parameter space allowed by current electromagnetic observations in an unbiased way. For each simulation, we construct the expected GW signal and identify the loudest individual sources. We then employ appropriate detection statistics to evaluate the relative probability of detecting each type of source as a function of time for a variety of PTAs; we consider the current International PTA (IPTA), and speculate into the era of the Square Kilometre Array (SKA). The main properties of the first detectable individual SBHBs are also investigated. Contrary to previous work, we cast our resu...

  15. HPLC-photodiode array detection analysis of curcuminoids in Curcuma species indigenous to Indonesia

    NARCIS (Netherlands)

    Bos, Rein; Windono, Tri; Woerdenbag, Herman J.; Boersma, Ykelien L.; Koulman, Albert; Kayser, Oliver

    An optimized HPLC method with photodiode array detection was developed and applied to analyse the curcuminoids curcumin, demethoxycurcumin, and bis-demethoxycurcumin in rhizomes of Curcuma mangga Val &. v. Zijp, C. heyneana Val. & v. Zijp, C. aeruginosa Roxb. and C. soloensis Val. (Zingiberaceae),

  16. HPLC-photodiode array detection analysis of curcuminoids in Curcuma species indigenous to Indonesia

    NARCIS (Netherlands)

    Bos, Rein; Windono, Tri; Woerdenbag, Herman J.; Boersma, Ykelien L.; Koulman, Albert; Kayser, Oliver

    2007-01-01

    An optimized HPLC method with photodiode array detection was developed and applied to analyse the curcuminoids curcumin, demethoxycurcumin, and bis-demethoxycurcumin in rhizomes of Curcuma mangga Val &. v. Zijp, C. heyneana Val. & v. Zijp, C. aeruginosa Roxb. and C. soloensis Val. (Zingiberaceae), i

  17. Systems and methods for detecting a failure event in a field programmable gate array

    Science.gov (United States)

    Ng, Tak-Kwong (Inventor); Herath, Jeffrey A. (Inventor)

    2009-01-01

    An embodiment generally relates to a method of self-detecting an error in a field programmable gate array (FPGA). The method includes writing a signature value into a signature memory in the FPGA and determining a conclusion of a configuration refresh operation in the FPGA. The method also includes reading an outcome value from the signature memory.

  18. Phased-Array Monolithic PEM for FT Spectrometry With Applications in Explosive Detection and CB Defense

    Science.gov (United States)

    2008-12-01

    1 PHASED-ARRAY MONOLITHIC PEM FOR FT SPECTROMETRY WITH APPLICATIONS IN EXPLOSIVE DETECTION AND CB DEFENSE Tudor N. Buican* Semiotic ...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Semiotic Engineering Associates LLC Albuquerque, NM 87108 8. PERFORMING ORGANIZATION REPORT NUMBER 9

  19. Development of the colorimetric sensor array for detection of explosives and volatile organic compounds in air

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Alstrøm, Tommy Sonne; Johnsen, C

    2010-01-01

    In the framework of the research project 'Xsense' at the Technical University of Denmark (DTU) we are developing a simple colorimetric sensor array which can be useful in detection of explosives like DNT and TNT, and identification of volatile organic compounds in the presence of water vapor in air...

  20. Membrane-based oligonucleotide array developed from multiple markers for the detection of many Phytophthora species.

    Science.gov (United States)

    Chen, Wen; Djama, Zeinab Robleh; Coffey, Michael D; Martin, Frank N; Bilodeau, Guillaume J; Radmer, Lorien; Denton, Geoff; Lévesque, C André

    2013-01-01

    Most Phytophthora spp. are destructive plant pathogens; therefore, effective monitoring and accurate early detection are important means of preventing potential epidemics and outbreaks of diseases. In the current study, a membrane-based oligonucleotide array was developed that can detect Phytophthora spp. reliably using three DNA regions; namely, the internal transcribed spacer (ITS), the 5' end of cytochrome c oxidase 1 gene (cox1), and the intergenic region between cytochrome c oxidase 2 gene (cox2) and cox1 (cox2-1 spacer). Each sequence data set contained ≈250 sequences representing 98 described and 15 undescribed species of Phytophthora. The array was validated with 143 pure cultures and 35 field samples. Together, nonrejected oligonucleotides from all three markers have the ability to reliably detect 82 described and 8 undescribed Phytophthora spp., including several quarantine or regulated pathogens such as Phytophthora ramorum. Our results showed that a DNA array containing signature oligonucleotides designed from multiple genomic regions provided robustness and redundancy for the detection and differentiation of closely related taxon groups. This array has the potential to be used as a routine diagnostic tool for Phytophthora spp. from complex environmental samples without the need for extensive growth of cultures.

  1. Fourier Array Processing for Buried Victims Detection using Ultra Wide Band Radar with Uncalibrated Sensors

    NARCIS (Netherlands)

    Lidicky, L.

    2008-01-01

    The purpose of this paper is to propose a new way to detect victims buried in or under layers of rubble or debris in case of disasters such as earthquakes, fires or terrorist attacks. The method is based on Fourier Processing and Principal Component Analysis (PCA). It utilizes a moving array of

  2. Quickest Detection of a Random Signal in Background Noise Using a Sensor Array

    Directory of Open Access Journals (Sweden)

    Poor H Vincent

    2005-01-01

    Full Text Available The problem of detecting the onset of a signal impinging at an unknown angle on a sensor array is considered. An algorithm based on parallel CUSUM tests matched to each of a set of discrete beamforming angles is proposed. Analytical approximations are developed for the mean time between false alarms, and for the detection delay of this algorithm. Simulations are included to verify the results of this analysis.

  3. Prospects of Gravitational Wave Detection Using Pulsar Timing Array for Chinese Future Telescopes

    Science.gov (United States)

    Lee, K. J.

    2016-02-01

    In this paper, we estimate the sensitivity of gravitational wave (GW) detection for future Chinese pulsar timing array (PTA) projects. The calculation of sensitivity is based on the well-known Crámer-Rao bound idea. The red noise and dispersion measure (DM) variation noise has be included in the modeling. We demonstrate that the future Chinese telescope can be very valuable for future PTA experiments and GW detection efforts.

  4. Graphene nano-ink biosensor arrays on a microfluidic paper for multiplexed detection of metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Labroo, Pratima; Cui, Yue, E-mail: yue.cui@usu.edu

    2014-02-01

    Graphical abstract: - Highlights: • We report graphene-ink biosensor arrays on a microfluidic paper for metabolites. • The device is able to detect multiple metabolites sensitively and rapidly. • The device fabrication process is simple and inexpensive. - Abstract: The development of a miniaturized and low-cost platform for the highly sensitive, selective and rapid detection of multiplexed metabolites is of great interest for healthcare, pharmaceuticals, food science, and environmental monitoring. Graphene is a delicate single-layer, two-dimensional network of carbon atoms with extraordinary electrical sensing capability. Microfluidic paper with printing technique is a low cost matrix. Here, we demonstrated the development of graphene-ink based biosensor arrays on a microfluidic paper for the multiplexed detection of different metabolites, such as glucose, lactate, xanthine and cholesterol. Our results show that the graphene biosensor arrays can detect multiple metabolites on a microfluidic paper sensitively, rapidly and simultaneously. The device exhibits a fast measuring time of less than 2 min, a low detection limit of 0.3 μM, and a dynamic detection range of 0.3–15 μM. The process is simple and inexpensive to operate and requires a low consumption of sample volume. We anticipate that these results could open exciting opportunities for a variety of applications.

  5. Coulometric determination of trace water in active carbonyl compounds using modified Karl Fischer reagents

    Energy Technology Data Exchange (ETDEWEB)

    Nordin-Andersson, I.; Cedergren, A.

    1987-03-01

    Improved conditions for the coulometric determination of trace water in samples containing potentially interfering substances like aldehydes and ketones were obtained by using a formamide-based, rapidly reacting Karl Fischer reagent in which methanol was replaced by 2-methoxyethanol. The shape of the potentiometric titration curves obtained by titrating spent Karl Fischer reagents with iodine indicates a less degree of triiodide formation in the presence of formamide. The corresponding increase in iodine results in a more rapid overall reaction rate since the reaction involving iodine is much more rapid than that with triiodide. For water amounts corresponding to less than 0.1% the stoichiometry of the Karl Fischer reaction was found to be 1:1, relatively independent of the concentration of 2-methoxyethanol. For larger amounts of water this stoichiometric ratio was attained by using a reagent containing 2-methoxyethanol/formamide 80/20 (v/v), 0.6 M imidazole, and 0.4 M sulfur dioxide.

  6. Investigation of amine-buffered amide reagents for coulometric Karl Fischer titration.

    Science.gov (United States)

    Larsson, William; Cedergren, Anders

    2009-06-15

    Formamide (FA), N-methylformamide (NMF), and dimethylformamide (DMF), were evaluated as solvents for coulometric Karl Fischer (KF) reagents in combination with several amine bases. Except for the effect of the iodine species (iodine or triiodide), the pH of the reagent and the position of the sulfur dioxide/hydrogen sulfite equilibrium were found to be the main factors explaining the large difference in the observed reaction rates between water and the KF reagent in these solvents. Acid-base titrations showed that hydrogen sulfite is the main sulfur reactant in these media. The results will be of great importance in finding suitable combinations of base and solvent with respect to stoichiometry, side reactions caused by active carbonyl compounds, and reagent stability.

  7. Smartphone coupled handheld array reader for real-time toxic gas detection.

    Science.gov (United States)

    Devadhasan, Jasmine Pramila; Kim, Dami; Lee, Do Young; Kim, Sanghyo

    2017-09-01

    Smartphones and related accessories are rapidly expanding their applications in various fields. Herein we developed a smartphone coupled handheld array reader with the integration of complementary metal oxide (CMOS) image sensor for detecting various toxic gases by colorimetric monitoring approach. In this study, toxic gases such as hydrogen fluoride (HF), chlorine (Cl2), ammonia (NH3), and formaldehyde (CH2O) were detected using titanium nanoparticles (TiO2 NPs) blended poly (vinyl alcohol) (PVA) hydrogel test strips, which were patterned with chemically responsive dyes. The dye colors changed based on acid-base reactions, and the colorimetric reader monitored the array strips and mapped them in the form of chrominance data. The observed signals transferred to a smartphone that displays the detected toxic gases and their exposure levels with the aid of the smartphone app "Toxic Gas Detection". The colorimetric array reader was precisely constructed with an auto-calibration system to minimize potential errors. Various concentration of toxic gases (0.5-10 ppm) were analyzed and achieved the detection limit of 1 ppm for each gas. Also, various analytical performance including sensitivity, stability, selectivity, and reproducibility analysis proved the reliability and accuracy of the detection system. Additionally, the smartphone app can be installed on any type of tablet, laptop, or other portable device. This study proved that smartphone coupled colorimetric array reader is a suitable system for detecting various toxic gases, chemicals and biochemical analysis with real-time monitoring approach. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Cued search algorithm with uncertain detection performance for phased array radars

    Institute of Scientific and Technical Information of China (English)

    Jianbin Lu; Hui Xiao; Zemin Xi; Mingmin Zhang

    2013-01-01

    A cued search algorithm with uncertain detection per-formance is proposed for phased array radars. Firstly, a target search model based on the information gain criterion is presented with known detection performance, and the statistical characteris-tic of the detection probability is calculated by using the fluctuant model of the target radar cross section (RCS). Secondly, when the detection probability is completely unknown, its probability den-sity function is modeled with a beta distribution, and its posterior probability distribution with the radar observation is derived based on the Bayesian theory. Final y simulation results show that the cued search algorithm with a known RCS fluctuant model can achieve the best performance, and the algorithm with the detection probability modeled as a beta distribution is better than that with a random selected detection probability because the model parame-ters can be updated by the radar observation to approach to the real value of the detection probability.

  9. Novel Wearable Device for Blood Leakage Detection during Hemodialysis Using an Array Sensing Patch

    Directory of Open Access Journals (Sweden)

    Yi-Chun Du

    2016-06-01

    Full Text Available Hemodialysis (HD is a clinical treatment that requires the puncturing of the body surface. However, needle dislodgement can cause a high risk of blood leakage and can be fatal to patients. Previous studies proposed several devices for blood leakage detection using optical or electrical techniques. Nonetheless, these methods used single-point detection and the design was not suitable for multi-bed monitoring. This study proposed a novel wearable device for blood leakage monitoring during HD using an array sensing patch. The array sensing patch combined with a mapping circuit and a wireless module could measure and transmit risk levels. The different risk levels could improve the working process of healthcare workers, and enhance their work efficiency and reduce inconvenience due to false alarms. Experimental results showed that each point of the sensing array could detect up to 0.1 mL of blood leakage and the array sensing patch supports a risk level monitoring system up to 8 h to alert healthcare personnel of pertinent danger to the patients.

  10. Comparison of Two Suspension Arrays for Simultaneous Detection of Five Biothreat Bacterial in Powder Samples

    Directory of Open Access Journals (Sweden)

    Yu Yang

    2012-01-01

    Full Text Available We have developed novel Bio-Plex assays for simultaneous detection of Bacillus anthracis, Yersinia pestis, Brucella spp., Francisella tularensis, and Burkholderia pseudomallei. Universal primers were used to amplify highly conserved region located within the 16S rRNA amplicon, followed by hybridized to pathogen-specific probes for identification of these five organisms. The other assay is based on multiplex PCR to simultaneously amplify five species-specific pathogen identification-targeted regions unique to individual pathogen. Both of the two arrays are validated to be flexible and sensitive for simultaneous detection of bioterrorism bacteria. However, universal primer PCR-based array could not identify Bacillus anthracis, Yersinia pestis, and Brucella spp. at the species level because of the high conservation of 16S rDNA of the same genus. The two suspension arrays can be utilized to detect Bacillus anthracis sterne spore and Yersinia pestis EV76 from mimic “write powder” samples, they also proved that the suspension array system will be valuable tools for diagnosis of bacterial biothreat agents in environmental samples.

  11. Simultaneous detection of lactate and glucose by integrated printed circuit board based array sensing chip

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuelian [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China); School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zang, Jianfeng [Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708 (United States); Liu, Yingshuai; Lu, Zhisong [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China); Li, Qing, E-mail: Qli@swu.edu.cn [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Li, Chang Ming, E-mail: ecmli@swu.edu.cn [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China)

    2013-04-10

    Highlights: ► An integrated printed circuit board (PCB) based array sensing chip was developed. ► Simultaneous detection of lactate and glucose in serum has been demonstrated. ► The array electronic biochip has high signal to noise ratio and high sensitivity. ► Additional electrodes were designed on the chip to correct interferences. -- Abstract: An integrated printed circuit board (PCB) based array sensing chip was developed to simultaneously detect lactate and glucose in mouse serum. The novelty of the chip relies on a concept demonstration of inexpensive high-throughput electronic biochip, a chip design for high signal to noise ratio and high sensitivity by construction of positively charged chitosan/redox polymer Polyvinylimidazole-Os (PVI-Os)/carbon nanotube (CNT) composite sensing platform, in which the positively charged chitosan/PVI-Os is mediator and electrostatically immobilizes the negatively charged enzyme, while CNTs function as an essential cross-linker to network PVI-Os and chitosan due to its negative charged nature. Additional electrodes on the chip with the same sensing layer but without enzymes were prepared to correct the interferences for high specificity. Low detection limits of 0.6 μM and 5 μM were achieved for lactate and glucose, respectively. This work could be extended to inexpensive array sensing chips with high sensitivity, good specificity and high reproducibility for various sensor applications.

  12. Array of Love-wave sensors based on quartz/Novolac to detect CWA simulants.

    Science.gov (United States)

    Matatagui, D; Fontecha, J; Fernández, M J; Aleixandre, M; Gràcia, I; Cané, C; Horrillo, M C

    2011-09-15

    An array of Love-wave sensors based on quartz and Novolac has been developed to detect chemical warfare agents (CWAs). These weapons are a risk for human health due to their efficiency and high lethality; therefore an early and clear detection is of enormous importance for the people safety. Love-wave devices realized on quartz as piezoelectric substrate and Novolac as guiding layer have been used to make up an array of six sensors, which have been coated with specific polymers by spin coating. The CWAs are very dangerous and for safety reasons their well known simulants have been used: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM) and dichloropentane (DCP). The array has been exposed to these CWA simulants detecting very low concentrations, such as 25 ppb of DMMP, a simulant of nerve agent sarin. Finally, principal component analysis (PCA) as data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as patterns classification technique have been applied. The performance of the sensor array has shown stability, accuracy, high sensitivity and good selectivity to these simulants.

  13. Rapid and specific detection of Lassa virus by reverse transcription-PCR coupled with oligonucleotide array hybridization.

    Science.gov (United States)

    Olschläger, Stephan; Günther, Stephan

    2012-07-01

    To facilitate sequence-specific detection of DNA amplified in a diagnostic reverse transcription (RT)-PCR for Lassa virus, we developed an array featuring 47 oligonucleotide probes for post-PCR hybridization of the amplicons. The array procedure may be performed with low-tech equipment and does not take longer than agarose gel detection.

  14. Detection of High Energy Cosmic Rays at the Auger Engineering Radio Array

    CERN Document Server

    de Jong, Sijbrand

    2016-01-01

    Detection of (ultra-) high-energy cosmic rays with the use of radio frequency emission from extensive air showers has been proven as complimentary to existing ground array detection techniques. Great progress has been made in the understanding of the emission processes and in their Monte Carlo modelling. These have led to experimental results, notably also at the Auger Engineering Radio Array, on energy, angular and mass composition resolution of the primary cosmic rays. Recent results are reported. The measured resolutions turn out to be competitive with existing techniques and they have independent uncertainties. Implications for cross-calibration with existing techniques and for future large-scale applications of radio detection of ultra-high-energy cosmic rays are discussed.

  15. Damage detection in multilayered fiber-metal laminates using guided-wave phased array

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Ameneh; Ohadi, Abdolrezap; Sadighi, Mojtaba; Amindavar, Hamidreza [Amirkabir University, Tehran (Iran, Islamic Republic of)

    2016-05-15

    This study employs the Lamb wave method to detect damage in Fiber-metal laminates (FMLs). The method is based on quasiisotropic behavior approximation and beam forming techniques. Delay and sum and minimum variance distorsionless response beam formers are applied to a uniform linear phased array. The simulation in finite element software is conducted to evaluate the performance of the presented procedure. The two types of damage studied are the following: (1) Delamination between fiber-epoxy and metal layers and (2) crack on the metal layer. The present study has the following important contributions: (1) Health monitoring of multi-damaged FMLs using Lamb waves and beam forming technique, (2) detection of damage type, (3) detection of damage size by 1D phased array, and (4) identification of damages that occurred very close to the laminate edges or close to each other.

  16. Arrays of TiO2 Nanowires as Photoelectrochemical Sensors for Hydrazine Detection

    Directory of Open Access Journals (Sweden)

    Michael Ongaro

    2015-05-01

    Full Text Available Electrodes based on arrays of TiO2 nanowires were prepared by template sol-gel synthesis with the goal of developing a hydrazine photoelectrochemical sensor. Experimental conditions were chosen so that the gelation reaction occurred inside the nanopores of track-etched polycarbonate membranes, with consequent filling with TiO2 nanowires. Different procedures for the removal of the template were examined, in order to obtain arrays of self-standing TiO2 nanowires. The nanowire arrays were bound to fluorine doped tin oxide substrates to produce handy photoelectrodes. The photocurrent recorded with the photoelectrodes in the presence of hydrazine showed significant dependence on the pollutant concentration. The development of a photoelectrochemical sensor for hydrazine detection in water samples, based on this principle, is presented.

  17. The Detection of an Extremely Bright Fast Radio Burst in a Phased Array Feed Survey

    Science.gov (United States)

    Bannister, K. W.; Shannon, R. M.; Macquart, J.-P.; Flynn, C.; Edwards, P. G.; O'Neill, M.; Osłowski, S.; Bailes, M.; Zackay, B.; Clarke, N.; D'Addario, L. R.; Dodson, R.; Hall, P. J.; Jameson, A.; Jones, D.; Navarro, R.; Trinh, J. T.; Allison, J.; Anderson, C. S.; Bell, M.; Chippendale, A. P.; Collier, J. D.; Heald, G.; Heywood, I.; Hotan, A. W.; Lee-Waddell, K.; Madrid, J. P.; Marvil, J.; McConnell, D.; Popping, A.; Voronkov, M. A.; Whiting, M. T.; Allen, G. R.; Bock, D. C.-J.; Brodrick, D. P.; Cooray, F.; DeBoer, D. R.; Diamond, P. J.; Ekers, R.; Gough, R. G.; Hampson, G. A.; Harvey-Smith, L.; Hay, S. G.; Hayman, D. B.; Jackson, C. A.; Johnston, S.; Koribalski, B. S.; McClure-Griffiths, N. M.; Mirtschin, P.; Ng, A.; Norris, R. P.; Pearce, S. E.; Phillips, C. J.; Roxby, D. N.; Troup, E. R.; Westmeier, T.

    2017-05-01

    We report the detection of an ultra-bright fast radio burst (FRB) from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide-field fly’s-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of 160 deg2, and achieve an exposure totaling 13200 deg2 hr . We constrain the position of FRB 170107 to a region 8\\prime × 8\\prime in size (90% containment) and its fluence to be 58 ± 6 Jy ms. The spectrum of the burst shows a sharp cutoff above 1400 MHz, which could be due to either scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright (> 20 Jy ms) population of FRBs.

  18. Colorimetric Sensor Arrays for the Detection and Identification of Chemical Weapons and Explosives.

    Science.gov (United States)

    Kangas, Michael J; Burks, Raychelle M; Atwater, Jordyn; Lukowicz, Rachel M; Williams, Pat; Holmes, Andrea E

    2017-03-04

    There is a significant demand for devices that can rapidly detect chemical-biological-explosive (CBE) threats on-site and allow for immediate responders to mitigate spread, risk, and loss. The key to an effective reconnaissance mission is a unified detection technology that analyzes potential threats in real time. In addition to reviewing the current state of the art in the field, this review illustrates the practicality of colorimetric arrays composed of sensors that change colors in the presence of analytes. This review also describes an outlook toward future technologies, and describes how they could possibly be used in areas such as war zones to detect and identify hazardous substances.

  19. Holographic method for site-resolved detection of a 2D array of ultracold atoms

    CERN Document Server

    Hoffmann, Daniel Kai; Limmer, Wolfgang; Denschlag, Johannes Hecker

    2016-01-01

    We propose a novel approach to site-resolved detection of a 2D gas of ultracold atoms in an optical lattice. A near resonant laser beam is coherently scattered by the atomic array and its interference pattern is holographically recorded by superimposing it with a reference laser beam on a CCD chip. Fourier transformation of the recorded intensity pattern reconstructs the atomic distribution in the lattice with single-site resolution. The holographic detection method requires only a few hundred scattered photons per atom in order to achieve a high reconstruction fidelity. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium.

  20. Seismic detections of the 15 February 2013 Chelyabinsk meteor from the dense ChinArray

    Science.gov (United States)

    Li, Lu; Wang, Baoshan; Peng, Zhigang; Wang, Weitao

    2016-08-01

    ChinArray is a dense portable broadband seismic network to cover the entire continental China, and the Phase I is deployed along the north-south seismic belt in southwest China. In this study, we analyze seismic data recorded on the ChinArray following the February 15, 2013 Chelyabinsk (Russia) meteor. This was the largest known object entering the Earth's atmosphere since the 1908 Tunguska meteor. The seismic energy radiated from this event was recorded by seismic stations worldwide including the dense ChinArray that are more than 4000 km away. The weak signal from the meteor event was contaminated by a magnitude 5.8 Tonga earthquake occurred ~20 min earlier. To test the feasibility of detecting the weak seismic signals from the meteor event, we compute vespagram and perform F-K analysis to the surface-wave data. We identify a seismic phase with back azimuth (BAZ) of 329.7° and slowness of 34.73 s/deg, corresponding to the surface wave from the Russian meteor event (BAZ ~325.97°). The surface magnitude ( M S) of the meteor event is 3.94 ± 0.18. We also perform similar analysis on the data from the broadband array F-net in Japan, and find the BAZ of the surface waves to be 316.61°. With the different BAZs of ChinArray and F-net, we locate the Russian meteor event at 58.80°N, 58.72°E. The relatively large mislocation (~438 km as compared with 55.15°N, 61.41°E by others) may be a result of the bending propagation path of surface waves, which deviates from the great circle path. Our results suggest that the dense ChinArray and its subarrays could be used to detect weak signals at teleseismic distances.

  1. Design of a detection system of highlight LED arrays' effect on the human organization

    Science.gov (United States)

    Chen, Shuwang; Shi, Guiju; Xue, Tongze; Liu, Yanming

    2009-05-01

    LED (Light Emitting Diode) has many advantages in the intensity, wavelength, practicality and price, so it is feasible to apply in biomedicine engineering. A system for the research on the effect of highlight LED arrays to human organization is designed. The temperature of skin surface can rise if skin and organization are in irradiation by highlight LED arrays. The metabolism and blood circulation of corresponding position will be quicker than those not in the shine, so the surface temperature will vary in different position of skin. The structure of LED source arrays system is presented and a measure system for studying LED's influence on human organization is designed. The temperature values of shining point are detected by infrared temperature detector. Temperature change is different according to LED parameters, such as the number, irradiation time and luminous intensity of LED. Experimental device is designed as an LED arrays pen. The LED arrays device is used to shine the points of human body, then it may effect on personal organization as well as the acupuncture. The system is applied in curing a certain skin disease, such as age pigment, skin cancer and fleck.

  2. Rapid detection of common viruses using multi-analyte suspension arrays.

    Science.gov (United States)

    Yu, Daojun; Wu, Shenghai; Wang, Baohong; Chen, Yunbo; Li, Lanjuan

    2011-10-01

    A method that uses specific oligonucleotide probes coupled to a specific array of fluorescent microspheres in multi-analyte suspension arrays was employed for the detection of common viruses, such as Herpes virus (HSV), Human papillomavirus (HPV) and Hepatitis B virus (HBV). Sixteen species-specific probes and 9 sets of specific primers were designed based on conserved sequences of these viruses in the GenBank database. Serial symmetric PCR, asymmetric PCR and multiple PCR assays were employed to evaluate the sensitivity, specificity and reproducibility of multi-analyte suspension arrays analyzed on a Luminex-100 analyzer instrument. The symmetric PCR amplification of four types of HSV, four types of HPV and HBV genotypes of B, C and D, combined with their corresponding species-specific probes and specificities were completely concordant with the results from a comparative sequence analyses. There was no significant difference in the median fluorescence intensity (MFI) value between symmetric PCR and asymmetric PCR when the viral DNA concentration was above 10(4)copies/test. Both PCR products were negative in the multi-analyte suspension arrays with viral DNA concentrations less than 10(3)copies/test. A multi-analyte suspension array is a flexible, high-throughput, relatively simple method for rapid identification of common viruses in the clinical laboratory. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Comparative genomic hybridization array study and its utility in detection of constitutional and acquired anomalies.

    Science.gov (United States)

    Andrieux, Joris; Sheth, Frenny

    2009-10-01

    The last decade has witnessed an upsurge in the knowledge of cytogenetic disorders and putting the old technology in a new basket with molecular genetics. As conventional cytogenetic can detect the genetic alteration of 10-15 Mb, many of the micro-deletions and micro-duplications are missed. However, with the advent of technology of fluorescence in situ hybridization (FISH), the resolution of genetic aberrations can reach to 3-5 Mb, nonetheless the anomalies smaller than the above, need further precision which has been achieved using comparative genomic hybridization array (CGH-array). Introduction of array-CGH has brought higher sensitivity with automated DNA fragment analyzer and DNA chip for submicroscopic chromosomal anomalies that are missed till date in many of the acquired and constitutional genetic disorders. The resolution of the technology varies from several Kb to 1 Mb depending upon the type of array selected. With the recent improvement in the array-CGH technology, a link between cytogenetic and molecular biology has been established without replacing conventional cytogenetic technique. The wider accessibility of the technology shall certainly provide a clue to the many unidentified/unexplained genetic disorders which shall prove to be a boon to the clinicians.

  4. Simulations of lesion detection using a combined phased array LHMI-technique.

    Science.gov (United States)

    Heikkilä, Janne; Hynynen, Kullervo

    2008-11-01

    Ultrasound based elasticity imaging techniques have been developed during the past decades. Some of these techniques are based on an internal radiation force stimulation in which a transient or dynamic radiation force is produced by using a single or dual-frequency sonication. In addition, sonication and data acquisition can be implemented using combined or separate transducers. In this simulation study of lesion detection using localized harmonic motion imaging (LHMI), we used a combined phased array designed for simultaneous thermal ablation and lesion detection. In the sonication mode, a focused single-frequency amplitude-modulated sonication is used to induce harmonic motion and in the tracking mode, some of the array elements are used for pulse-echo tracking of the induced displacements. The results showed that the size of the lesion affected the induced displacement around the sonication point. The displacement tracking simulations demonstrated that these changes in the displacement distributions can be detected using only a few of the array elements in the tracking mode but the exact size of the lesion can not be detected accurately. The simulations also showed that two lesions having the radius of 2.5mm can be distinguished if distance between these lesions is at least 2.5mm.

  5. Detecting super-Nyquist-frequency gravitational waves using a pulsar timing array

    Science.gov (United States)

    Yi, Shu-Xu; Zhang, Shuang-Nan

    2016-08-01

    The maximum frequency of gravitational waves (GWs) detectable with traditional pulsar timing methods is set by the Nyquist frequency ( f Ny) of the observation. Beyond this frequency, GWs leave no temporal-correlated signals; instead, they appear as white noise in the timing residuals. The variance of the GW-induced white noise is a function of the position of the pulsars relative to the GW source. By observing this unique functional form in the timing data, we propose that we can detect GWs of frequency > f Ny (super-Nyquist frequency GWs; SNFGWs). We demonstrate the feasibility of the proposed method with simulated timing data. Using a selected dataset from the Parkes Pulsar Timing Array data release 1 and the North American Nanohertz Observatory for Gravitational Waves publicly available datasets, we try to detect the signals from single SNFGW sources. The result is consistent with no GW detection with 65.5% probability. An all-sky map of the sensitivity of the selected pulsar timing array to single SNFGW sources is generated, and the position of the GW source where the selected pulsar timing array is most sensitive to is λs = -0.82, βs = -1.03 (rad); the corresponding minimum GW strain is h = 6.31 × 10-11 at f = 1 × 10-5 Hz.

  6. Detection of H pylori antibody profile in serum by protein array

    Institute of Scientific and Technical Information of China (English)

    Feng-Chan Han; Xu-Jun Li; Hong Jiang; Li-Peng Qin; Ding Li; Yan-Hai Guo; Zhi-Guang Liu; Li Zhang; Xiao-Jun Yan

    2006-01-01

    AIM: To detect multiple H pylori antibodies in serum samples of individuals who carryH pyloriby protein array.METHODS: Recombinant H pyloriantigens, urease B subunit (UreB), vacuolating toxin A (VacA) and cytotoxin associated gene A protein (CagA), were prepared and immobilized in matrixes on nitrocellulose membrane by robotics to bind the specific immunoglobulin G (IgG) antibodies in serum. Staphylococcus protein A (SPA) labeled by colloid gold was used to integrate the immuno-complex and gave red color signal, The scanner based on charge-coupled device (CCD) could collect the image signal and convert it into digital signal.RESULTS: When human IgG was printed on the membrane in increasing concentrations and incubated with immunogold, a linear dose response curve was obtained and the detection limit for IgG was about 0.025 ng. The cutoff values, which were defined as the mean grey level plus 3 times of standard deviation, were 27.183, 28.546 and 27.402, for anti-UreB IgG, antiCagA IgG and anti-VacA IgG, respectively, as 400 human serum samples with negative H pylori antibodies were detected by the protein array. When 180 serum samples from patients in hospital were employed for detection of IgG against UreB, CagA and VacA, the sensitivity of the protein array was 93.4%, 95.4%, 96.0%, and the specificity was 94.8%, 94.4% and 97.5%, respectively,as compared with the results obtained by ELISA. The assay also showed high reproducibility, uniformity and stability, and the results were available within 30 min.CONCLUSION: The protein array is a very practical method for rapid detection of multiple antibodies in serum samples. It is especially useful for large scale epidemiological investigation of the infection of Hpylori.

  7. Charged-particle detection efficiencies of close-packed CsI arrays

    Science.gov (United States)

    Morfouace, P.; Lynch, W. G.; Tsang, M. B.

    2017-03-01

    Detector efficiency determination is essential to correct the measured yields and extract reliable cross sections of particles emitted in nuclear reactions. We investigate the efficiencies for measuring the full energies of light charged particle in arrays of CsI crystals employed in particle detection arrays such as HiRA, LASSA and MUST2. We perform these simulations with a GEANT4 Monte Carlo transport code implemented in the NPTool framework. Both Coulomb multiple scattering and nuclear reactions within the crystal can significantly reduce the efficiency of detecting the full energy of high energy particles. The calculated efficiencies decrease exponentially as a function of the range of the particle and are quite similar for both the hydrogen (p , d , t) and helium (3He, α) isotopes. The use of a close-packed array introduces significant position dependent efficiency losses at the interior boundaries between crystals that need to be considered in the design of an array and in the efficiency corrections of measured energy spectra.

  8. Colorimetric sensor array for detection and identification of organophosphorus and carbamate pesticides.

    Science.gov (United States)

    Qian, Sihua; Lin, Hengwei

    2015-01-01

    Due to relatively low persistence and high effectiveness for insect and pest eradication, organophosphates (OPs) and carbamates are the two major classes of pesticides that broadly used in agriculture. Hence, the sensitive and selective detection of OPs and carbamates is highly significant. In this current study, a colorimetric sensor array comprising five inexpensive and commercially available thiocholine and H2O2 sensitive indicators for the simultaneous detection and identification of OPs and carbamates is developed. The sensing mechanism of this array is based on the irreversible inhibition capability of OPs and carbamates to the activity of acetylcholinesterase (AChE), preventing production of thiocholine and H2O2 from S-acetylthiocholine and acetylcholine and thus resulting in decreased or no color reactions to thiocholine and H2O2 sensitive indicators. Through recognition patterns and standard statistical methods (i.e., hierarchical clustering analysis and principal component analysis), the as-developed array demonstrates not only discrimination of OPs and carbamates from other kinds of pesticides but, more interestingly, identification of them exactly from each other. Moreover, this array is experimentally confirmed to have high selectivity and sensitivity, good anti-interference capability, and potential applications in real samples for OPs and carbamates.

  9. A theoretical study of the interference from chlorine in the oxidative coulometric method for trace determination of sulphur in hydrocarbons.

    Science.gov (United States)

    Cedergren, A

    1975-12-01

    A theoretical investigation has been made of the interference from chlorine in the oxidative coulometric method for trace sulphur determinations. A computer program (SOLGAS), based on the free-energy minimization principle, has been used to predict equilibrium compositions of the products resulting from combustion of a hydrocarbon sample containing sulphur and chlorine. The theoretical possibilities of overcoming the interference from chlorine and maintaining a high recovery of sulphur are described.

  10. Application of Ultrasonic Phased Array Technology to the Detection of Defect in Composite Stiffened-structures

    Science.gov (United States)

    Zhou, Yuan-Qi; Zhan, Li-Hua

    2016-05-01

    Composite stiffened-structure consists of the skin and stringer has been widely used in aircraft fuselage and wings. The main purpose of the article is to detect the composite material reinforced structure accurately and explore the relationship between defect formation and structural elements or curing process. Based on ultrasonic phased array inspection technology, the regularity of defects in the manufacture of composite materials are obtained, the correlation model between actual defects and nondestructive testing are established. The article find that the forming quality of deltoid area in T-stiffened structure is obviously improved by pre-curing, the defects of hat-stiffened structure are affected by the mandrel. The results show that the ultrasonic phased array inspection technology can be an effectively way for the detection of composite stiffened-structures, which become an important means to control the defects of composite and improve the quality of the product.

  11. Coincidence detection of spatially correlated photon pairs with a monolithic time-resolving detector array

    CERN Document Server

    Unternährer, Manuel; Gasparini, Leonardo; Stoppa, David; Stefanov, André

    2016-01-01

    We demonstrate coincidence measurements of spatially entangled photons by means of a novel type of multi-pixel based detection array. The adopted sensor is a fully digital 8$\\times$16 silicon photomultiplier array allowing not only photon counting but also per-pixel time stamping of the arrived photons with a resolution of 65 ps. Together with a frame rate of 500 kfps, this property exceeds the capabilities of conventional charge-coupled device cameras which have become of growing interest for the detection of transversely correlated photon pairs. The sensor is used to measure a second-order correlation function for various non-collinear configurations of entangled photons generated by spontaneous parametric down-conversion. The experimental results are compared to theory.

  12. Calibration of the Neutral Current Detection Array in the SNO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cox, G.A. [University of Washington, Seattle, US (United States); Cleveland, B.T. [University of Oxford, Oxford (United Kingdom); Di Marco, M. [Queen' s University, Kingston (Canada); present address: University of Geneva, Geneva (Switzerland); Evans, H.C.; Guillian, E.; Hallin, A.L. [Queen' s University, Kingston (Canada); Huang, M. [University of Texas, Austin (United States); Howard, C. [Queen' s University, Kingston (Canada); Jelley, N.A. [University of Oxford, Oxford (United Kingdom); Law, J. [University of Guelph, Guelph (Canada); Loach, J.C. [University of Oxford, Oxford (United Kingdom); Lawrence Berkeley National Laboratory, Berkeley (United States); O' Keeffe, H.M. [University of Oxford, Oxford (United Kingdom); Kraus, C.; Krauss, C.B. [Queen' s University, Kingston (Canada); McGee, S. [present address: University of Geneva, Geneva, Switserland (Switzerland); Peeters, S.J.M., E-mail: s.peeters1@physics.ox.ac.uk [University of Oxford, Oxford (United Kingdom); Prior, G. [University of Texas, Austin (United States); Lawrence Berkeley National Laboratory, Berkeley (United States); Rielage, K. [Los Alamos National Laboratory, Los Alamos (United States); Reitzner, D. [University of Guelph, Guelph (Canada); Skensved, P. [Queen' s University, Kingston (Canada); and others

    2011-12-15

    Since November 25th, 2004, the Sudbury Neutrino Observatory has been taking production data in its third and final phase. For this phase a 'Neutral-Current Detection (NCD) Array', consisting of 36 strings of {sup 3}He proportional counters and 4 strings of {sup 4}He proportional counters, was deployed in SNO's D{sub 2}O volume. It supplements the Cherenkov detector, consisting of 9456 photomultiplier tubes, present in the previous two phases by offering an independent measurement of the solar neutral current rate. The {sup 3}He counters detect neutrons from neutrino-deuteron neutral current interactions in the D{sub 2}O. We describe the calibration of this array.

  13. Operation and performance of the EEE network array for the detection of cosmic rays

    Science.gov (United States)

    Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Licciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

    2017-02-01

    The EEE (Extreme Energy Events) Project is an experiment for the detection of cosmic ray muons by means of a sparse array of telescopes, each made of three Multigap Resistive Plate Chambers (MRPC), distributed over all the Italian territory and at CERN. The main scientific goals of the Project are the investigation of the properties of the local muon flux, the detection of Extensive Air Showers (EAS) and the search for long-distance correlations between far telescopes. The Project is also characterized by a strong educational and outreach aspect since the telescopes are managed by teams of students and teachers who had previously constructed them at CERN. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array, which currently consists of more than 50 telescopes, is also presented by showing the most recent physics results.

  14. Array microscopy technology and its application to digital detection of Mycobacterium tuberculosis

    Science.gov (United States)

    McCall, Brian P.

    Tuberculosis causes more deaths worldwide than any other curable infectious disease. This is the case despite tuberculosis appearing to be on the verge of eradication midway through the last century. Efforts at reversing the spread of tuberculosis have intensified since the early 1990s. Since then, microscopy has been the primary frontline diagnostic. In this dissertation, advances in clinical microscopy towards array microscopy for digital detection of Mycobacterium tuberculosis are presented. Digital array microscopy separates the tasks of microscope operation and pathogen detection and will reduce the specialization needed in order to operate the microscope. Distributing the work and reducing specialization will allow this technology to be deployed at the point of care, taking the front-line diagnostic for tuberculosis from the microscopy center to the community health center. By improving access to microscopy centers, hundreds of thousands of lives can be saved. For this dissertation, a lens was designed that can be manufactured as 4x6 array of microscopes. This lens design is diffraction limited, having less than 0.071 waves of aberration (root mean square) over the entire field of view. A total area imaged onto a full-frame digital image sensor is expected to be 3.94 mm2, which according to tuberculosis microscopy guidelines is more than sufficient for a sensitive diagnosis. The design is tolerant to single point diamond turning manufacturing errors, as found by tolerance analysis and by fabricating a prototype. Diamond micro-milling, a fabrication technique for lens array molds, was applied to plastic plano-concave and plano-convex lens arrays, and found to produce high quality optical surfaces. The micro-milling technique did not prove robust enough to produce bi-convex and meniscus lens arrays in a variety of lens shapes, however, and it required lengthy fabrication times. In order to rapidly prototype new lenses, a new diamond machining technique was

  15. Detection and Localization with an Acoustic Array on a Small Robotic Platform in Urban Environments

    Science.gov (United States)

    2003-01-01

    Detection and Localization with an Acoustic Array on a Small Robotic Platform in Urban Environments by Stuart H. Young and Michael V. Scanlon...Environments Stuart H. Young Computational and Information Sciences Directorate, ARL Michael V. Scanlon Sensors and Electron Devices Directorate...for soldiers, law enforcement, and rescue personnel and can remove these people from hazardous environments. ARL’s primary robotic platforms contain

  16. A novel device based on a fluorescent cross-responsive sensor array for detecting pesticide residue

    Science.gov (United States)

    Huang, Jing; Hou, Changjun; Lei, Jincan; Huo, Danqun; Luo, Xiaogang; Dong, Liang

    2016-11-01

    In this paper, a novel, simple, rapid, and low-cost detection device for pesticide residue was constructed. A sensor array based on a cross-responsive mechanism was designed. The data collection and processing system was used to detect fluorescent signal of the sensor arrays, and to extract unique patterns of the tested pesticide residue. Four selected pesticides, carbendazim, diazine, fenvalerate, and pentachloronitrobenzene, were detected by the proposed device. Unsupervised pattern recognition methods, hierarchical cluster analysis and principal component analysis, were used to analyze the data. The results showed that the methods could 100% discriminate the four pesticide residues. According to the standard regression linear curve of the fluorescence intensity and the concentration of pesticide, the quantitative value of the pesticide was detected, and the device obtained responses at concentrations below 8 ppb, and it has a good linear relationship in the range of 0.01-1 ppm. According to the results, the proposed detection device showed excellent selectivity and discrimination ability for the pesticide residues. However, our preliminary study demonstrated that the proposed detection device has excellent potential application for the safety inspection of food.

  17. A strategy for selective detection based on interferent depleting and redox cycling using the plane-recessed microdisk array electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Feng [State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Yan Jiawei, E-mail: jwyan@xmu.edu.cn [State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Lu Miao [Pen-Tung Sah Micro-Nano Technology Research Center, Xiamen University, Xiamen, Fujian 361005 (China); Zhou Yongliang; Yang Yang; Mao Bingwei [State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)

    2011-10-01

    Highlights: > A novel strategy based on a combination of interferent depleting and redox cycling is proposed for the plane-recessed microdisk array electrodes. > The strategy break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction. > The electrodes enhance the current signal by redox cycling. > The electrodes can work regardless of the reversibility of interfering species. - Abstract: The fabrication, characterization and application of the plane-recessed microdisk array electrodes for selective detection are demonstrated. The electrodes, fabricated by lithographic microfabrication technology, are composed of a planar film electrode and a 32 x 32 recessed microdisk array electrode. Different from commonly used redox cycling operating mode for array configurations such as interdigitated array electrodes, a novel strategy based on a combination of interferent depleting and redox cycling is proposed for the electrodes with an appropriate configuration. The planar film electrode (the plane electrode) is used to deplete the interferent in the diffusion layer. The recessed microdisk array electrode (the microdisk array), locating within the diffusion layer of the plane electrode, works for detecting the target analyte in the interferent-depleted diffusion layer. In addition, the microdisk array overcomes the disadvantage of low current signal for a single microelectrode. Moreover, the current signal of the target analyte that undergoes reversible electron transfer can be enhanced due to the redox cycling between the plane electrode and the microdisk array. Based on the above working principle, the plane-recessed microdisk array electrodes break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction, which is a limitation of single redox cycling operating mode. The advantages of the

  18. Simultaneous Detection of Fenitrothion and Chlorpyrifos-Methyl with a Photonic Suspension Array.

    Directory of Open Access Journals (Sweden)

    Xuan Wang

    Full Text Available A technique was developed for simultaneous detection of fenitrothion (FNT and chlorpyrifos-methyl (CLT using a photonic suspension array based on silica colloidal crystal beads (SCCBs. The SCCBs were encoded with the characteristic reflection peak originating from the stop-band of colloidal crystal. This approach avoids the bleaching, fading or potential interference seen when encoding by fluorescence. SCCBs with a nanopatterned surface had increased biomolecule binding capacity and improved stability. Under optimal conditions, the proposed suspension array allowed simultaneous detection of the selected pesticides in the ranges of 0.25 to 1024 ng/mL and 0.40 to 735.37 ng/mL, with the limits of detection (LODs of 0.25 and 0.40 ng/mL, respectively. The suspension array was specific and had no significant cross-reactivity with other chemicals. The mean recoveries in tests in which samples were spiked with target standards were 82.35% to 109.90% with a standard deviation within 9.93% for CLT and 81.64% to 108.10% with a standard deviation within 8.82% for FNT. The proposed method shows a potentially powerful capability for fast quantitative analysis of pesticide residues.

  19. Detecting MLC errors in stereotactic radiotherapy plans with a liquid filled ionization chamber array.

    Science.gov (United States)

    O'Connor, Patrick; Seshadri, Venkatakrisnan; Charles, Paul

    2016-03-01

    Quality assurance of stereotactic radiotherapy demands the use of equipment with the highest resolution and sensitivity available. This study examines the sensitivity of a commercially available liquid-filled ionization chamber array--the Octavius 1000 SRS (PTW, Frieburg, Germany) for detecting small (sub-millimetre) multi-leaf collimator (MLC) alignment errors in static square fields (side length 16-40 mm). Furthermore, the effectiveness of detecting small MLC errors in clinical stereotactic radiotherapy patient plans using the device was also evaluated. The commonly used gamma pass rate metric (of the measurements compared with treatment planning system generated results) was used. The gamma pass rates were then evaluated as a function of MLC position error (MLC error size 0.1-2.5 mm). The detector array exhibited a drop in pass rate between plans without error and those which had MLC errors induced. For example a drop in pass rate of 4.5% (gamma criteria 3%, 1 mm) was observed when a 0.8 mm error was introduced into a 16 mm square field. Furthermore the drop in pass rate increased as the MLC position error increased. This study showed that the Octavius 1000 SRS array could be a useful tool for applications requiring the detection of small geometric delivery uncertainties.

  20. The study of structural color filter based on periodic nanohole arrays for bio-detection

    Science.gov (United States)

    Kim, Seunguk; Shin, Jeonghee; Yoo, Seungjun; Kim, Samhwan; Jeon, Byoungok; Moon, Cheil; Jang, Jae-Eun

    2015-07-01

    A nanostructure which induces localized surface plasmon resonance (LSPR) can be utilized in visible light and near infrared (NIR) regions and it shows promising features as a bio-detector because LSPR state is changed easily by different bio-related materials. Owing to transparent property of many biomolecules as well as diluted states in base solutions, it is hard to distinguish each other by eye or microscope analysis. However, difference in molecular structure and composition makes difference in optical characteristics such as a refractive index or a dielectric constant. Therefore, our LSPR-based nanohole array structure which has high sensitivity to detect small changes in optical characteristics can be a great candidate for a bio detector. Here, we fabricated structural color filters (SCFs) to detect wavelength shifts for several biomolecules and optimized the nanohole array structures for high sensitivity. Periodic nanohole arrays were designed to present resonance peaks in visible light region for optical analysis and fabricated in Au or Al thin film layer. The spectral shifts were detected caused by biomolecules.

  1. A simple optimization can improve the performance of single feature polymorphism detection by Affymetrix expression arrays

    Directory of Open Access Journals (Sweden)

    Fujisawa Hironori

    2010-05-01

    Full Text Available Abstract Background High-density oligonucleotide arrays are effective tools for genotyping numerous loci simultaneously. In small genome species (genome size: Results We compared the single feature polymorphism (SFP detection performance of whole-genome and transcript hybridizations using the Affymetrix GeneChip® Rice Genome Array, using the rice cultivars with full genome sequence, japonica cultivar Nipponbare and indica cultivar 93-11. Both genomes were surveyed for all probe target sequences. Only completely matched 25-mer single copy probes of the Nipponbare genome were extracted, and SFPs between them and 93-11 sequences were predicted. We investigated optimum conditions for SFP detection in both whole genome and transcript hybridization using differences between perfect match and mismatch probe intensities of non-polymorphic targets, assuming that these differences are representative of those between mismatch and perfect targets. Several statistical methods of SFP detection by whole-genome hybridization were compared under the optimized conditions. Causes of false positives and negatives in SFP detection in both types of hybridization were investigated. Conclusions The optimizations allowed a more than 20% increase in true SFP detection in whole-genome hybridization and a large improvement of SFP detection performance in transcript hybridization. Significance analysis of the microarray for log-transformed raw intensities of PM probes gave the best performance in whole genome hybridization, and 22,936 true SFPs were detected with 23.58% false positives by whole genome hybridization. For transcript hybridization, stable SFP detection was achieved for highly expressed genes, and about 3,500 SFPs were detected at a high sensitivity (> 50% in both shoot and young panicle transcripts. High SFP detection performances of both genome and transcript hybridizations indicated that microarrays of a complex genome (e.g., of Oryza sativa can be

  2. Report for Development of a Census Array and Evaluation of the Array to Detect Biothreat Agents and Environmental Samples for DHS

    Energy Technology Data Exchange (ETDEWEB)

    Jaing, C; Jackson, P

    2011-04-14

    The objective of this project is to provide DHS a comprehensive evaluation of the current genomic technologies including genotyping, Taqman PCR, multiple locus variable tandem repeat analysis (MLVA), microarray and high-throughput DNA sequencing in the analysis of biothreat agents from complex environmental samples. This report focuses on the design, testing and results of samples on the Census Array. We designed a Census/Detection Array to detect all sequenced viruses (including phage), bacteria (eubacteria), and plasmids. Family-specific probes were selected for all sequenced viral and bacterial complete genomes, segments, and plasmids. Probes were designed to tolerate some sequence variation to enable detection of divergent species with homology to sequenced organisms, and to be unique relative to the human genome. A combination of 'detection' probes with high levels of conservation within a family plus 'census' probes targeting strain/isolate specific regions enabled detection and taxonomic classification from the level of family down to the strain. The array has wider coverage of bacterial and viral targets based on more recent sequence data and more probes per target than other microbial detection/discovery arrays in the literature. We tested the array with purified bacterial and viral DNA/RNA samples, artificial mixes of known bacterial/viral samples, spiked DNA against complex background including BW aerosol samples and soil samples, and environmental samples to evaluate the array's sensitivity and forensic capability. The data were analyzed using our novel maximum likelihood software. For most of the organisms tested, we have achieved at least species level discrimination.

  3. A Compact, Low-Power Cantilever-Based Sensor Array for Chemical Detection

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; Ratto, T; Wilson, T; Mukerjee, E; Hu, Z; Sulchek, T; Hart, B

    2007-02-22

    A compact and low-power cantilever-based sensor array has been developed and used to detect various vapor analytes. This device employs sorptive polymers that are deposited onto piezoresistive cantilevers. We have successfully detected several organic vapors, representing a breadth of chemical properties and over a range of concentrations. Comparisons of the polymer/vapor partition coefficient to the cantilever deflection responses show that a simple linear relationship does not exist, emphasizing the need to develop an appropriate functional model to describe the chemical-to-mechanical transduction that is unique to this sensing modality.

  4. Towards the installation and use of an extended array for cosmic ray detection The EEE Project

    CERN Document Server

    Abbrescia, M; An, S; Antolini, R; Badala, A; Baek, Y W; Baldini Ferroli, R; Bencivenni, G; Blanco, F; Bressan, E; Chiavassa, A; Chiri,C; Cicalò, C; Cifarelli, L; Coccia, E; Coccetti, F; De Caro, A; De Gruttola, D; De Pasquale, S; D'Incecco, M; Fabbri, F L; Frolov, V; Garbini, M; Garnaccia, C; Gustavino, C; Hatzifotiadou, D; Imponente, G; Kim, J S; Kim, M M; La Rocca, P; Librizzi, F; Maggiora, A; Menghetti, H; Miozzi, S; Moro, R; Noferini, F; Pagano, P; Panareo, M; Pappalardo, G S; Petta, C; Piragino, G; Preghenella, R; Riggi, F; Romano, F; Russo, G; Sartorelli, G; Sbarra, C; Scioli, G; Selvi, M; Serci, S; Siddi, E; Wenninger, H; Williams, M C S; Zampolli, C; Zichichi, A; Zuyeuski, R

    2009-01-01

    The Extreme Energy Events (EEE) project started to use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) allows the study of the local muon flux, the detection of cosmic ray showers and the search for correlations between distant showers. The project is also intended to involve high school teams in an advanced research work. The present status of the installation and the first physics results are discussed here.

  5. Performance of Narrowband Signal Detection under Correlated Rayleigh Fading Based on Synthetic Array

    Directory of Open Access Journals (Sweden)

    Ali Broumandan

    2009-01-01

    design parameters of probability of detection (Pd and probability of false alarm (Pfa. An optimum detector based on Estimator-Correlator (EC is developed, and its performance is compared with that of suboptimal Equal-Gain (EG combiner in different channel correlation scenarios. It is shown that in moderate channel correlation scenarios the detection performance of EC and EG is identical. The sensitivity of the proposed method to knowledge of motion parameters is also investigated. An extensive set of measurements based on CDMA-2000 pilot signals using the static antenna and synthetic array are used to experimentally verify these theoretical findings.

  6. Towards the installation and use of an extended array for cosmic ray detection: The EEE Project

    Science.gov (United States)

    Abbrescia, M.; Alici, A.; An, S.; Antolini, R.; Badalà, A.; Baek, Y. W.; Baldini Ferroli, R.; Bencivenni, G.; Blanco, F.; Bressan, E.; Chiavassa, A.; Chiri, C.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Coccetti, F.; de Caro, A.; de Gruttola, D.; de Pasquale, S.; D'Incecco, M.; Fabbri, F. L.; Frolov, V.; Garbini, M.; Guarnaccia, C.; Gustavino, C.; Hatzifotiadou, D.; Imponente, G.; Kim, J. S.; Kim, M. M.; La Rocca, P.; Librizzi, F.; Maggiora, A.; Menghetti, H.; Miozzi, S.; Moro, R.; Noferini, F.; Pagano, P.; Panareo, M.; Pappalardo, G. S.; Petta, C.; Piragino, G.; Preghenella, R.; Riggi, F.; Romano, F.; Russo, G.; Sartorelli, G.; Sbarra, C.; Scioli, G.; Selvi, M.; Serci, S.; Siddi, E.; Wenninger, H.; Williams, M. C. S.; Zampolli, C.; Zichichi, A.; Zuyeuski, R.

    2009-05-01

    The Extreme Energy Events (EEE) project started to use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) allows the study of the local muon flux, the detection of cosmic ray showers and the search for correlations between distant showers. The project is also intended to involve high school teams in an advanced research work. The present status of the installation and the first physics results are discussed here.

  7. Development of array piezoelectric fingers towards in vivo breast tumor detection

    Science.gov (United States)

    Xu, Xin; Chung, Youngsoo; Brooks, Ari D.; Shih, Wei-Heng; Shih, Wan Y.

    2016-12-01

    We have investigated the development of a handheld 4 × 1 piezoelectric finger (PEF) array breast tumor detector system towards in vivo patient testing, particularly, on how the duration of the DC applied voltage, the depression depth of the handheld unit, and breast density affect the PEF detection sensitivity on 40 patients. The tests were blinded and carried out in four phases: with DC voltage durations 5, 3, 2, to 0.8 s corresponding to scanning a quadrant, a half, a whole breast, and both breasts within 30 min, respectively. The results showed that PEF detection sensitivity was unaffected by shortening the applied voltage duration from 5 to 0.8 s nor was it affected by increasing the depression depth from 2 to 6 mm. Over the 40 patients, PEF detected 46 of the 48 lesions (46/48)—with the smallest lesion detected being 5 mm in size. Of 28 patients (some have more than one lesion) with mammography records, PEF detected 31/33 of all lesions (94%) and 14/15 of malignant lesions (93%), while mammography detected 30/33 of all lesions (91%) and 12/15 of malignant lesions (80%), indicating that PEF could detect malignant lesions not detectable by mammography without significantly increasing false positives. PEF's detection sensitivity is also shown to be independent of breast density, suggesting that PEF could be a potential tool for detecting breast cancer in young women and women with dense breasts.

  8. Evaluation of GenoFlow DR-MTB Array Test for Detection of Rifampin and Isoniazid Resistance in Mycobacterium tuberculosis

    Science.gov (United States)

    Molina-Moya, B.; Kazdaglis, G.; Lacoma, A.; Prat, C.; Gómez, A.; Villar-Hernández, R.; García-García, E.; Haba, L.; Maldonado, J.; Samper, S.; Ruiz-Manzano, J.; Ausina, V.

    2016-01-01

    The aim of this study was to evaluate the GenoFlow DR-MTB array test (DiagCor Bioscience, Hong Kong) on 70 cultured isolates and 50 sputum specimens. The GenoFlow array test showed good sensitivity and specificity compared to the phenotypic Bactec 460TB. This array accurately detected mutations in rpoB, katG, and inhA associated with resistance to rifampin and isoniazid. PMID:26865688

  9. Automatic Defect Detection for TFT-LCD Array Process Using Quasiconformal Kernel Support Vector Data Description

    Directory of Open Access Journals (Sweden)

    Yi-Hung Liu

    2011-09-01

    Full Text Available Defect detection has been considered an efficient way to increase the yield rate of panels in thin film transistor liquid crystal display (TFT-LCD manufacturing. In this study we focus on the array process since it is the first and key process in TFT-LCD manufacturing. Various defects occur in the array process, and some of them could cause great damage to the LCD panels. Thus, how to design a method that can robustly detect defects from the images captured from the surface of LCD panels has become crucial. Previously, support vector data description (SVDD has been successfully applied to LCD defect detection. However, its generalization performance is limited. In this paper, we propose a novel one-class machine learning method, called quasiconformal kernel SVDD (QK-SVDD to address this issue. The QK-SVDD can significantly improve generalization performance of the traditional SVDD by introducing the quasiconformal transformation into a predefined kernel. Experimental results, carried out on real LCD images provided by an LCD manufacturer in Taiwan, indicate that the proposed QK-SVDD not only obtains a high defect detection rate of 96%, but also greatly improves generalization performance of SVDD. The improvement has shown to be over 30%. In addition, results also show that the QK-SVDD defect detector is able to accomplish the task of defect detection on an LCD image within 60 ms.

  10. Automatic defect detection for TFT-LCD array process using quasiconformal kernel support vector data description.

    Science.gov (United States)

    Liu, Yi-Hung; Chen, Yan-Jen

    2011-01-01

    Defect detection has been considered an efficient way to increase the yield rate of panels in thin film transistor liquid crystal display (TFT-LCD) manufacturing. In this study we focus on the array process since it is the first and key process in TFT-LCD manufacturing. Various defects occur in the array process, and some of them could cause great damage to the LCD panels. Thus, how to design a method that can robustly detect defects from the images captured from the surface of LCD panels has become crucial. Previously, support vector data description (SVDD) has been successfully applied to LCD defect detection. However, its generalization performance is limited. In this paper, we propose a novel one-class machine learning method, called quasiconformal kernel SVDD (QK-SVDD) to address this issue. The QK-SVDD can significantly improve generalization performance of the traditional SVDD by introducing the quasiconformal transformation into a predefined kernel. Experimental results, carried out on real LCD images provided by an LCD manufacturer in Taiwan, indicate that the proposed QK-SVDD not only obtains a high defect detection rate of 96%, but also greatly improves generalization performance of SVDD. The improvement has shown to be over 30%. In addition, results also show that the QK-SVDD defect detector is able to accomplish the task of defect detection on an LCD image within 60 ms.

  11. Helmet-mounted acoustic array for hostile fire detection and localization in an urban environment

    Science.gov (United States)

    Scanlon, Michael V.

    2008-04-01

    The detection and localization of hostile weapons firing has been demonstrated successfully with acoustic sensor arrays on unattended ground sensors (UGS), ground-vehicles, and unmanned aerial vehicles (UAVs). Some of the more mature systems have demonstrated significant capabilities and provide direct support to ongoing counter-sniper operations. The Army Research Laboratory (ARL) is conducting research and development for a helmet-mounted system to acoustically detect and localize small arms firing, or other events such as RPG, mortars, and explosions, as well as other non-transient signatures. Since today's soldier is quickly being asked to take on more and more reconnaissance, surveillance, & target acquisition (RSTA) functions, sensor augmentation enables him to become a mobile and networked sensor node on the complex and dynamic battlefield. Having a body-worn threat detection and localization capability for events that pose an immediate danger to the soldiers around him can significantly enhance their survivability and lethality, as well as enable him to provide and use situational awareness clues on the networked battlefield. This paper addresses some of the difficulties encountered by an acoustic system in an urban environment. Complex reverberation, multipath, diffraction, and signature masking by building structures makes this a very harsh environment for robust detection and classification of shockwaves and muzzle blasts. Multifunctional acoustic detection arrays can provide persistent surveillance and enhanced situational awareness for every soldier.

  12. Detection of Volatile Organics Using a Surface Acoustic Wave Array System

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, LAWRENCE F.; BARTHOLOMEW, JOHN W.; CERNOSEK, RICHARD W.; COLBURN, CHRISTOPHER W.; CROOKS, R.M.; MARTINEZ, R.F.; OSBOURN, GORDON C.; RICCO, A.J.; STATON, ALAN W.; YELTON, WILLIAM G.

    1999-10-14

    A chemical sensing system based on arrays of surface acoustic wave (SAW) delay lines has been developed for identification and quantification of volatile organic compounds (VOCs). The individual SAW chemical sensors consist of interdigital transducers patterned on the surface of an ST-cut quartz substrate to launch and detect the acoustic waves and a thin film coating in the SAW propagation path to perturb the acoustic wave velocity and attenuation during analyte sorption. A diverse set of material coatings gives the sensor arrays a degree of chemical sensitivity and selectivity. Materials examined for sensor application include the alkanethiol-based self-assembled monolayer, plasma-processed films, custom-synthesized conventional polymers, dendrimeric polymers, molecular recognition materials, electroplated metal thin films, and porous metal oxides. All of these materials target a specific chemical fi.mctionality and the enhancement of accessible film surface area. Since no one coating provides absolute analyte specificity, the array responses are further analyzed using a visual-empirical region-of-influence (VERI) pattern recognition algorithm. The chemical sensing system consists of a seven-element SAW array with accompanying drive and control electronics, sensor signal acquisition electronics, environmental vapor sampling hardware, and a notebook computer. Based on data gathered for individual sensor responses, greater than 93%-accurate identification can be achieved for any single analyte from a group of 17 VOCs and water.

  13. Spectroscopic benzene detection using a broadband monolithic DFB-QCL array

    Science.gov (United States)

    Lewicki, Rafał; Witinski, Mark; Li, Biao; Wysocki, Gerard

    2016-03-01

    Quantitative laser spectroscopic measurements of complex molecules that have a broad absorption spectra require broadly tunable laser sources operating preferably in the mid-infrared molecular fingerprint region. In this paper a novel broadband mid-infrared laser source comprising of an array of single-mode distributed feedback quantum cascade lasers was used to target a broadband absorption feature of benzene (C6H6), a toxic and carcinogenic atmospheric pollutant. The DFB-QCL array is a monolithic semiconductor device with no opto-mechanical components, which eliminates issues with mechanical vibrations. The DFB-QCLs array used in this work provides spectral coverage from 1022.5 cm-1 to 1053.3 cm-1, which is sufficient to access the absorption feature of benzene at 1038 cm-1 (9.64 μm). A sensor prototype based on a 76 m multipass cell (AMAC-76LW, Aerodyne Research) and a dispersive DFB-QCL array beam combiner was developed and tested. The Allan deviation analysis of the retrieved benzene concentration data yields a short-term precision of 100 ppbv/Hz1/2 and a minimum detectable concentration of 12 ppbv for 200 s averaging time. The system was also tested by sampling atmospheric air as well as vapors of different chemical products that contained traces of benzene.

  14. Array CGH improves detection of mutations in the GALC gene associated with Krabbe disease

    Directory of Open Access Journals (Sweden)

    Tanner Alice K

    2012-06-01

    Full Text Available Abstract Background Krabbe disease is an autosomal recessive lysosomal storage disorder caused by mutations in the GALC gene. The most common mutation in the Caucasian population is a 30-kb deletion of exons 11 through 17. There are few other reports of intragenic GALC deletions or duplications, due in part to difficulties detecting them. Methods and results We used gene-targeted array comparative genomic hybridization (CGH to analyze the GALC gene in individuals with Krabbe disease in whom sequence analysis with 30-kb deletion analysis identified only one mutation. In our sample of 33 cases, traditional approaches failed to identify two pathogenic mutations in five (15.2% individuals with confirmed Krabbe disease. The addition of array CGH deletion/duplication analysis to the genetic testing strategy led to the identification of a second pathogenic mutation in three (9.1% of these five individuals. In all three cases, the deletion or duplication identified through array CGH was a novel GALC mutation, including the only reported duplication in the GALC gene, which would have been missed by traditional testing methodologies. We report these three cases in detail. The second mutation remains unknown in the remaining two individuals (6.1%, despite our full battery of testing. Conclusions Analysis of the GALC gene using array CGH deletion/duplication testing increased the two-mutation detection rate from 84.8% to 93.9% in affected individuals. Better mutation detection rates are important for improving molecular diagnosis of Krabbe disease, as well as for providing prenatal and carrier testing in family members.

  15. A unified algorithm for target detection and tracing based on data of array sensors

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong; CHEN Fuhu

    2008-01-01

    A unified method for target detection and tracing based on data from sensors of array is presented in order to improve detection and tracking abilities of the weak targets with low signal-to-noise ratio. Assuming that the multiple targets are uncorrelated each other and the number of the targets is known a priori, the status of the targets can be estimated with the maximum a-posteriori (MAP) method directly through the sensors data. The proposed method is different from the classical method, by which it can detect and track targets simultaneously by adding the target's signal energy information besides its direction of arrival(DOA) information.Simulated and sea trial data results show that the detection and tracing capabilities of weak targets can be improved and wrong tracing and missing tracing problems, which exist in the classical tracing method when it is faced with the crossing targets, can be resolved by the proposed method.

  16. Determination of diarylheptanoids from Alpinia officinarum (Lesser Galangal) by HPLC with photodiode array and electrochemical detection.

    Science.gov (United States)

    Liu, Zhihua; Sang, Shengmin; Hartman, Thomas G; Ho, Chi-Tang; Rosen, Robert T

    2005-01-01

    Normal-phase column chromatography followed by semi-preparative reversed-phase HPLC has been used to isolate, from the rhizomes of Alpinia officinarum, five diarylheptanoids identified as 5-hydroxy-7-(4"-hydroxy-3"-methoxyphenyl)-1-phenyl-3-heptanone, 5-methoxy-7-(4"-hydroxy-3"-methoxyphenyl)-1-phenyl-3-heptanone, 7-(4"-hydroxyphenyl)-1-phenylhept-4-en-3-one, 7-(4"-hydroxy-3"-methoxyphenyl)-1-phenyl-hept-4-en-3-one, 1,7-diphenylhept-4-en-3-one. The levels of these five diarylheptanoids in root material were determined quantitatively by HPLC with UV detection and the assay methods so developed were simple, rapid and accurate. Four of the diarylheptanoids could also be detected by HPLC with electrochemical detection (ECD) in the oxidative mode, and ECD was found to have a higher sensitivity than photodiode array detection.

  17. Design of an Acoustic Target Intrusion Detection System Based on Small-Aperture Microphone Array

    Science.gov (United States)

    Zu, Xingshui; Guo, Feng; Huang, Jingchang; Zhao, Qin; Liu, Huawei; Li, Baoqing; Yuan, Xiaobing

    2017-01-01

    Automated surveillance of remote locations in a wireless sensor network is dominated by the detection algorithm because actual intrusions in such locations are a rare event. Therefore, a detection method with low power consumption is crucial for persistent surveillance to ensure longevity of the sensor networks. A simple and effective two-stage algorithm composed of energy detector (ED) and delay detector (DD) with all its operations in time-domain using small-aperture microphone array (SAMA) is proposed. The algorithm analyzes the quite different velocities between wind noise and sound waves to improve the detection capability of ED in the surveillance area. Experiments in four different fields with three types of vehicles show that the algorithm is robust to wind noise and the probability of detection and false alarm are 96.67% and 2.857%, respectively. PMID:28273838

  18. Neutrino Detection, Position Calibration and Marine Science with Acoustic Arrays in the Deep Sea

    CERN Document Server

    Lahmann, Robert

    2013-01-01

    Arrays of acoustic receivers are an integral part of present and potential future Cherenkov neutrino telescopes in the deep sea. They measure the positions of individual detector elements which vary with time as an effect of undersea currents. At the same time, the acoustic receivers can be employed for marine science purposes, in particular for monitoring the ambient noise environment and the signals emitted by the fauna of the sea. And last but not least, they can be used for studies towards acoustic detection of ultra-high-energy neutrinos. Measuring acoustic pressure pulses in huge underwater acoustic arrays with an instrumented volume of the order of 100 km^3 is a promising approach for the detection of cosmic neutrinos with energies exceeding 1 EeV. Pressure signals are produced by the particle cascades that evolve when neutrinos interact with nuclei in water, and can be detected over large distances in the kilometre range. In this article, the status of acoustic detection will be reviewed and plans for...

  19. Zero-crossing detection algorithm for arrays of optical spatial filtering velocimetry sensors

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Pedersen, Finn; Hanson, Steen Grüner

    2008-01-01

    This paper presents a zero-crossing detection algorithm for arrays of compact low-cost optical sensors based on spatial filtering for measuring fluctuations in angular velocity of rotating solid structures. The algorithm is applicable for signals with moderate signal-to-noise ratios, and delivers...... a "real-time" output (0-1 kHz). The sensors use optical spatial-filtering velocimetry on the dynamical speckles arising from scattering off a rotating solid object with a non-specular surface. The technology measures the instantaneous angular velocity of a target, without being biased by any linear...... factor is directly related to the thermal expansion and refractive-index coefficients of the optics (> 10(-5) K-1 for glass). By cascade-coupling an array of sensors, the ensemble-averaged angular velocity is measured in "real-time". This will reduce the influence of pseudo-vibrations arising from...

  20. A Sensor Array for the Detection and Discrimination of Methane and Other Environmental Pollutant Gases

    Science.gov (United States)

    Hannon, Ami; Lu, Yijiang; Li, Jing; Meyyappan, M.

    2016-01-01

    We address the sensitive detection and discrimination of gases impacting the environment, such as CH4, NH3, SO2, and CO, using a sensor array and aided by principal component analysis (PCA). A 32-element chemiresistive sensor array consisting of nine different sensor materials including seven types of modified single-walled carbon nanotubes and two types of polymers has been constructed. PCA results demonstrate excellent discriminating ability of the chemiresistor sensor chip in the 1–30 ppm concentration range. The accuracy of the sensor was verified against data collected using cavity ring down spectroscopy. The sensor chip has also been integrated with a smartphone and has been shown to reproduce the sensing performance obtained with the laboratory measurement system. PMID:27463716

  1. A Sensor Array for the Detection and Discrimination of Methane and Other Environmental Pollutant Gases

    Directory of Open Access Journals (Sweden)

    Ami Hannon

    2016-07-01

    Full Text Available We address the sensitive detection and discrimination of gases impacting the environment, such as CH4, NH3, SO2, and CO, using a sensor array and aided by principal component analysis (PCA. A 32-element chemiresistive sensor array consisting of nine different sensor materials including seven types of modified single-walled carbon nanotubes and two types of polymers has been constructed. PCA results demonstrate excellent discriminating ability of the chemiresistor sensor chip in the 1–30 ppm concentration range. The accuracy of the sensor was verified against data collected using cavity ring down spectroscopy. The sensor chip has also been integrated with a smartphone and has been shown to reproduce the sensing performance obtained with the laboratory measurement system.

  2. A new method of preparing fiber-optic DNA biosensor and its array for gene detection

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new method of preparing fiber-optic DNA biosensor and its arrayfor the simultaneous detection of multiple genes is described. The optical fibers were first treated with poly-l-lysine, and then were made into fiber-optic DNA biosensors by adsorbing and immobilizing the oligonucleotide probe on its end. By assembling the fiber-optic DNA biosensors in a bundle in which each fiber carried a different DNA probe, the fiber-optic DNA biosensor array was well prepared. Hybridization of fluorescent- labeled cDNA of p53 gene, N-ras gene and Rb1 gene to the DNA array was monitored by CCD camera. A good result was achieved.

  3. The Auger Engineering Radio Array and multi-hybrid cosmic ray detection

    Science.gov (United States)

    Holt, E. M.; Pierre Auger Collaboration

    2016-05-01

    The Auger Engineering Radio Array (AERA) aims at the detection of air showers induced by high-energy cosmic rays. As an extension of the Pierre Auger Observatory, it measures complementary information to the particle detectors, fluorescence telescopes and to the muon scintillators of the Auger Muons and Infill for the Ground Array (AMIGA). AERA is sensitive to all fundamental parameters of an extensive air shower such as the arrival direction, energy and depth of shower maximum. Since the radio emission is induced purely by the electromagnetic component of the shower, in combination with the AMIGA muon counters, AERA is perfect for separate measurements of the electrons and muons in the shower, if combined with a muon counting detector like AMIGA. In addition to the depth of the shower maximum, the ratio of the electron and muon number serves as a measure of the primary particle mass.

  4. A Sensor Array for the Detection and Discrimination of Methane and Other Environmental Pollutant Gases.

    Science.gov (United States)

    Hannon, Ami; Lu, Yijiang; Li, Jing; Meyyappan, M

    2016-07-25

    We address the sensitive detection and discrimination of gases impacting the environment, such as CH₄, NH₃, SO₂, and CO, using a sensor array and aided by principal component analysis (PCA). A 32-element chemiresistive sensor array consisting of nine different sensor materials including seven types of modified single-walled carbon nanotubes and two types of polymers has been constructed. PCA results demonstrate excellent discriminating ability of the chemiresistor sensor chip in the 1-30 ppm concentration range. The accuracy of the sensor was verified against data collected using cavity ring down spectroscopy. The sensor chip has also been integrated with a smartphone and has been shown to reproduce the sensing performance obtained with the laboratory measurement system.

  5. Compressive sensing based spinning mode detections by in-duct microphone arrays

    Science.gov (United States)

    Yu, Wenjun; Huang, Xun

    2016-05-01

    This paper presents a compressive sensing based experimental method for detecting spinning modes of sound waves propagating inside a cylindrical duct system. This method requires fewer dynamic pressure sensors than the number required by the Shannon-Nyquist sampling theorem so long as the incident waves are sparse in spinning modes. In this work, the proposed new method is firstly validated by preparing some of the numerical simulations with representative set-ups. Then, a duct acoustic testing rig with a spinning mode synthesiser and an in-duct microphone array is built to experimentally demonstrate the new approach. Both the numerical simulations and the experiment results are satisfactory, even when the practical issue of the background noise pollution is taken into account. The approach is beneficial for sensory array tests of silent aeroengines in particular and some other engineering systems with duct acoustics in general.

  6. Comprehensive GMO detection using real-time PCR array: single-laboratory validation.

    Science.gov (United States)

    Mano, Junichi; Harada, Mioko; Takabatake, Reona; Furui, Satoshi; Kitta, Kazumi; Nakamura, Kosuke; Akiyama, Hiroshi; Teshima, Reiko; Noritake, Hiromichi; Hatano, Shuko; Futo, Satoshi; Minegishi, Yasutaka; Iizuka, Tayoshi

    2012-01-01

    We have developed a real-time PCR array method to comprehensively detect genetically modified (GM) organisms. In the method, genomic DNA extracted from an agricultural product is analyzed using various qualitative real-time PCR assays on a 96-well PCR plate, targeting for individual GM events, recombinant DNA (r-DNA) segments, taxon-specific DNAs, and donor organisms of the respective r-DNAs. In this article, we report the single-laboratory validation of both DNA extraction methods and component PCR assays constituting the real-time PCR array. We selected some DNA extraction methods for specified plant matrixes, i.e., maize flour, soybean flour, and ground canola seeds, then evaluated the DNA quantity, DNA fragmentation, and PCR inhibition of the resultant DNA extracts. For the component PCR assays, we evaluated the specificity and LOD. All DNA extraction methods and component PCR assays satisfied the criteria set on the basis of previous reports.

  7. A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection

    Directory of Open Access Journals (Sweden)

    San-Shan Hung

    2016-12-01

    Full Text Available A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2′-bipyridyl dichlororuthenium(II hexahydrate and Tris(bipyridineruthenium(II chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

  8. A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection.

    Science.gov (United States)

    Hung, San-Shan; Chang, Hsing-Cheng; Chang, I-Nan

    2016-12-08

    A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2'-bipyridyl) dichlororuthenium(II) hexahydrate and Tris(bipyridine)ruthenium(II) chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

  9. Robotic vehicle uses acoustic array for detection and localization in urban environments

    Science.gov (United States)

    Young, Stuart H.; Scanlon, Michael V.

    2001-09-01

    Sophisticated robotic platforms with diverse sensor suites are quickly replacing the eyes and ears of soldiers on the complex battlefield. The Army Research Laboratory (ARL) in Adelphi, Maryland has developed a robot-based acoustic detection system that will detect an impulsive noise event, such as a sniper's weapon firing or door slam, and activate a pan-tilt to orient a visible and infrared camera toward the detected sound. Once the cameras are cued to the target, onboard image processing can then track the target and/or transmit the imagery to a remote operator for navigation, situational awareness, and target detection. Such a vehicle can provide reconnaissance, surveillance, and target acquisition for soldiers, law enforcement, and rescue personnel, and remove these people from hazardous environments. ARL's primary robotic platforms contain 16-in. diameter, eight-element acoustic arrays. Additionally, a 9- in. array is being developed in support of DARPA's Tactical Mobile Robot program. The robots have been tested in both urban and open terrain. The current acoustic processing algorithm has been optimized to detect the muzzle blast from a sniper's weapon, and reject many interfering noise sources such as wind gusts, generators, and self-noise. However, other detection algorithms for speech and vehicle detection/tracking are being developed for implementation on this and smaller robotic platforms. The collaboration between two robots, both with known positions and orientations, can provide useful triangulation information for more precise localization of the acoustic events. These robots can be mobile sensor nodes in a larger, more expansive, sensor network that may include stationary ground sensors, UAVs, and other command and control assets. This report will document the performance of the robot's acoustic localization, describe the algorithm, and outline future work.

  10. Coulometric determination of dissolved hydrogen with a multielectrolytic modified carbon felt electrode-based sensor

    Institute of Scientific and Technical Information of China (English)

    Hiroaki Matsuura; Yosuke Yamawaki; Kosuke Sasaki; Shunichi Uchiyama

    2013-01-01

    A multielectrolytic modified carbon electrode (MEMCE) was fabricated by the electrolytic-oxidation/reduction processes.First,the functional groups containing nitrogen atoms such as amino group were introduced by the electrode oxidation of carbon felt electrode in an ammonium carbamate aqueous solution,and next,this electrode was electroreduced in sulfuric acid.The redox waves between hydrogen ion and hydrogen molecule at highly positive potential range appeared in the cyclic voltammogram obtained by MEMCE.A coulometric cell using MEMCE with a catalytic activity of electrooxidation of hydrogen molecule was constructed and was used for the measurement of dissolved hydrogen.The typical current vs.time curve was obtained by the repetitive measurement of the dissolved hydrogen.These curves indicated that the measurement of dissolved hydrogen was finished completely in a very short time (ca.10sec).A linear relationship was obtained between the electrical charge needed for the electrooxidation process of hydrogen molecule and dissolved hydrogen concentration.This indicates that the developed coulometfic method can be used for the determination of the dissolved hydrogen concentration.

  11. Statistical Optimization of Evaporative Light Scattering Detection for Molten Sucrose Octaacetate and Comparison With Ultraviolet Diode Array Detection Validation Parameters Using Tandem HPLC Ultraviolet Diode Array Detection/Evaporative Light Scattering Detection-Specific Stability-Indicating Method.

    Science.gov (United States)

    Parmar, Rudrangi; Ghanta, Ajay; Haware, Rahul V; Johnson, Paul R; Stagner, William C

    2016-12-01

    A sucrose octaacetate (SOA) gradient HPLC evaporative light scattering detection (ELSD) and low-wavelength UV-diode array detection (UV-DAD)-specific stability-indicating method development and validation comparison is reported. A central composite response surface design and multicriteria optimization was used to maximize molten SOA area-under-the-curve response and signal-to-noise ratio. The ELSD data were also analyzed using multivariate principal component analysis, analysis of variance, and standard least squares effects modeling. The method suitability and validation parameters of both methods were compared. To the authors' knowledge, this is the first report that validates an ELSD method using a molten analyte. SOA exhibited a low molar absorptivity of 439 absorption units/cm/M in water at 210 nm requiring low-wavelength UV-DAD detection. The low-wavelength UV-DAD method provided substantially better intraday and interday precision, intraday and interday goodness-of-fit, detection limit, and quantitation limit than ELSD. ELSD exhibited a 60-fold greater area-under-the-curve response, better resolution, and 58% more theoretical plates. On balance, the UV-DAD method was chosen for SOA chemical kinetic studies. This study illustrates that ELSD may not always be the best alternative to gradient HPLC low-wavelength UV detection. Copyright © 2016. Published by Elsevier Inc.

  12. Detection of chromothripsis‐like patterns with a custom array platform for chronic lymphocytic leukemia

    Science.gov (United States)

    Salaverria, Itziar; Martín‐Garcia, David; López, Cristina; Clot, Guillem; García‐Aragonés, Manel; Navarro, Alba; Delgado, Julio; Baumann, Tycho; Pinyol, Magda; Martin‐Guerrero, Idoia; Carrió, Ana; Costa, Dolors; Queirós, Ana C.; Jayne, Sandrine; Aymerich, Marta; Villamor, Neus; Colomer, Dolors; González, Marcos; López‐Guillermo, Armando; Campo, Elías; Dyer, Martin J. S.; Siebert, Reiner; Armengol, Lluís

    2015-01-01

    Chronic lymphocytic leukemia (CLL) is a common disease with highly variable clinical course. Several recurrent chromosomal alterations are associated with prognosis and may guide risk‐adapted therapy. We have developed a targeted genome‐wide array to provide a robust tool for ascertaining abnormalities in CLL and to overcome limitations of the 4‐marker fluorescence in situ hybridization (FISH). DNA from 180 CLL patients were hybridized to the qChip®Hemo array with a high density of probes covering commonly altered loci in CLL (11q22‐q23, 13q14, and 17p13), nine focal regions (2p15‐p16.1, 2p24.3, 2q13, 2q36.3‐q37.1, 3p21.31, 8q24.21, 9p21.3, 10q24.32, and 18q21.32‐q21.33) and two larger regions (6q14.1‐q22.31 and 7q31.33‐q33). Overall, 86% of the cases presented copy number alterations (CNA) by array. There was a high concordance of array findings with FISH (84% sensitivity, 100% specificity); all discrepancies corresponded to subclonal alterations detected only by FISH. A chromothripsis‐like pattern was detected in eight cases. Three showed concomitant shattered 5p with gain of TERT along with isochromosome 17q. Presence of 11q loss was associated with shorter time to first treatment (P = 0.003), whereas 17p loss, increased genomic complexity, and chromothripsis were associated with shorter overall survival (P < 0.001, P = 0.001, and P = 0.02, respectively). In conclusion, we have validated a targeted array for the diagnosis of CLL that accurately detects, in a single experiment, all relevant CNAs, genomic complexity, chromothripsis, copy number neutral loss of heterozygosity, and CNAs not covered by the FISH panel. This test may be used as a practical tool to stratify CLL patients for routine diagnostics or clinical trials. © 2015 The Authors. Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc. PMID:26305789

  13. Fibre Optic Readout of Microcantilever Arrays for Fast Microorganism Growth Detection

    Directory of Open Access Journals (Sweden)

    N. Maloney

    2012-01-01

    Full Text Available We present a fibre-optic-based device for the automated readout of microcantilever arrays for fast microorganism growth detection. We determined the ability of our device to track shifts in resonance frequency due to an increase in mass on the cantilever surface or changes in mechanical stiffness. The resonance frequency response of 7 μm thick agarose-functionalised cantilevers was tracked as humidity levels were varied revealing a mass responsivity of ~51±1 pg/Hz. The resonance response of microcantilevers coated with Aspergillus niger (A. niger spores was monitored for >48 h revealing a growth detection time of >4 h. The growth of mycelium along the cantilevers surface is seen to result in an increase in resonance frequency due to the reinforcement of the cantilever structure. The use of our fibre optic detection technique allows data to be recorded continuously and faster than previously reported.

  14. Sensitive and Selective Detection of HIV-1 RRE RNA Using Vertical Silicon Nanowire Electrode Array

    Science.gov (United States)

    Lee, Jaehyung; Hong, Min-Ho; Han, Sanghun; Na, Jukwan; Kim, Ilsoo; Kwon, Yong-Joon; Lim, Yong-beom; Choi, Heon-Jin

    2016-07-01

    In this study, HIV-1 Rev response element (RRE) RNA was detected via an Au-coated vertical silicon nanowire electrode array (VSNEA). The VSNEA was fabricated by combining bottom-up and top-down approaches and then immobilized by artificial peptides for the recognition of HIV-1 RRE. Differential pulse voltammetry (DPV) analysis was used to measure the electrochemical response of the peptide-immobilized VSNEA to the concentration and types of HIV-1 RRE RNA. DPV peaks showed linearity to the concentration of RNA with a detection limit down to 1.513 fM. It also showed the clear different peaks to the mutated HIV-1 RRE RNA. The high sensitivity and selectivity of VSNEA for the detection of HIV-1 RRE RNA may be attributed to the high surface-to-volume ratio and total overlap diffusion mode of ions of the one-dimensional nanowire electrodes.

  15. Design and Implementation of Video Shot Detection on Field Programmable Gate Arrays

    Directory of Open Access Journals (Sweden)

    Jharna Majumdar

    2012-09-01

    Full Text Available Video has become an interactive medium of communication in everyday life. The sheer volume of video makes it extremely difficult to browse through and find the required data. Hence extraction of key frames from the video which represents the abstract of the entire video becomes necessary. The aim of the video shot detection is to find the position of the shot boundaries, so that key frames can be selected from each shot for subsequent processing such as video summarization, indexing etc. For most of the surveillance applications like video summery, face recognition etc., the hardware (real time implementation of these algorithms becomes necessary. Here in this paper we present the architecture for simultaneous accessing of consecutive frames, which are then used for the implementation of various Video Shot Detection algorithms. We also present the real time implementation of three video shot detection algorithms using the above mentioned architecture on FPGA (Field Programmable Gate Arrays.

  16. An electrochemical immunosensor based on interdigitated array microelectrode for the detection of chlorpyrifos.

    Science.gov (United States)

    Cao, Yaoyao; Sun, Xia; Guo, Yemin; Zhao, Wenping; Wang, Xiangyou

    2015-02-01

    An electrochemical immunosensor based on interdigitated array microelectrodes (IDAMs) was developed for sensitive, specific and rapid detection of chlorpyrifos. Anti-chlorpyrifos monoclonal antibodies were orientedly immobilized onto the gold microelectrode surface through protein A. Chlorpyrifos were then captured by the immobilized antibody, resulting in an impedance change in the IDAMs surface. Electrochemical impedance spectroscopy was used in conjunction with the fabricated sensor to detect chlorpyrifos. Under optimum conditions, the impedance value change of chlorpyrifos was proportional to its concentrations in the range of 10(0)-10(5) ng/mL. The detection limit was found to be 0.014 ng/mL for chlorpyrifos. The proposed chlorpyrifos immunosensor could be used as a screening method in pesticide determination for the analysis of environmental, agricultural and pharmaceutical samples due to its rapidity, sensitivity and low cost.

  17. Simultaneous Detection of Different MicroRNA Types Using the ZIP-Code Array System

    Science.gov (United States)

    Weishaupt, Sonja U.; Rupp, Steffen

    2013-01-01

    MicroRNAs (miRNAs) are important negative regulators of gene expression. Their implication in tumorigenesis is based on their dysregulation in many human cancer diseases. Interestingly, in tumor cells, an altered ratio of precursor and mature miRNA levels has been described. Consequently, differences in miRNA type levels have a high potential as biomarkers and comparative high-throughput-based detection might permit a more accurate characterization of subtypes, especially in the case of very heterogeneous tumor entities. Several molecular methods exist for the detection of mature and precursor miRNAs. DNA microarrays are predestinated as a high-throughput method for comprehensive miRNA detection in tumors. However, the simultaneous array-based detection of both these miRNA types is limited because the mature miRNA sequence is identically present in both forms. Here we present a ZIP-code DNA microarray-based system in combination with a novel labeling approach, which enables the simultaneous detection of precursor and mature miRNAs in one single experiment. Using synthetic miRNA templates, we demonstrate the specificity of the method for the different miRNA types, as well as the detection range up to four orders of magnitude. Moreover, mature and precursor miRNAs were detected and validated in human tumor cells. PMID:24078866

  18. Simultaneous Detection of Different MicroRNA Types Using the ZIP-Code Array System

    Directory of Open Access Journals (Sweden)

    Sonja U. Weishaupt

    2013-01-01

    Full Text Available MicroRNAs (miRNAs are important negative regulators of gene expression. Their implication in tumorigenesis is based on their dysregulation in many human cancer diseases. Interestingly, in tumor cells, an altered ratio of precursor and mature miRNA levels has been described. Consequently, differences in miRNA type levels have a high potential as biomarkers and comparative high-throughput-based detection might permit a more accurate characterization of subtypes, especially in the case of very heterogeneous tumor entities. Several molecular methods exist for the detection of mature and precursor miRNAs. DNA microarrays are predestinated as a high-throughput method for comprehensive miRNA detection in tumors. However, the simultaneous array-based detection of both these miRNA types is limited because the mature miRNA sequence is identically present in both forms. Here we present a ZIP-code DNA microarray-based system in combination with a novel labeling approach, which enables the simultaneous detection of precursor and mature miRNAs in one single experiment. Using synthetic miRNA templates, we demonstrate the specificity of the method for the different miRNA types, as well as the detection range up to four orders of magnitude. Moreover, mature and precursor miRNAs were detected and validated in human tumor cells.

  19. The microbial detection array for detection of emerging viruses in clinical samples--a useful panmicrobial diagnostic tool

    DEFF Research Database (Denmark)

    Rosenstierne, Maiken W; McLoughlin, Kevin S; Olesen, Majken Lindholm

    2014-01-01

    emerging viruses or common infections, making these unexpected pathogens difficult to diagnose. Broad-spectrum pathogen detection microarrays containing probes for all sequenced viruses and bacteria can provide rapid identification of viruses, guiding decisions about treatment and appropriate case......Emerging viruses are usually endemic to tropical and sub-tropical regions of the world, but increased global travel, climate change and changes in lifestyle are believed to contribute to the spread of these viruses into new regions. Many of these viruses cause similar disease symptoms as other...... management. We report a modified Whole Transcriptome Amplification (WTA) method that increases unbiased amplification, particular of RNA viruses. Using this modified WTA method, we tested the specificity and sensitivity of the Lawrence Livermore Microbial Detection Array (LLMDA) against a wide range...

  20. Evaluation of a miniature microscope objective designed for fluorescence array microscopy detection of Mycobacterium tuberculosis.

    Science.gov (United States)

    McCall, Brian; Olsen, Randall J; Nelles, Nicole J; Williams, Dawn L; Jackson, Kevin; Richards-Kortum, Rebecca; Graviss, Edward A; Tkaczyk, Tomasz S

    2014-03-01

    A prototype miniature objective that was designed for a point-of-care diagnostic array microscope for detection of Mycobacterium tuberculosis and previously fabricated and presented in a proof of concept is evaluated for its effectiveness in detecting acid-fast bacteria. To evaluate the ability of the microscope to resolve submicron features and details in the image of acid-fast microorganisms stained with a fluorescent dye, and to evaluate the accuracy of clinical diagnoses made with digital images acquired with the objective. The lens prescription data for the microscope design are presented. A test platform is built by combining parts of a standard microscope, a prototype objective, and a digital single-lens reflex camera. Counts of acid-fast bacteria made with the prototype objective are compared to counts obtained with a standard microscope over matched fields of view. Two sets of 20 smears, positive and negative, are diagnosed by 2 pathologists as sputum smear positive or sputum smear negative, using both a standard clinical microscope and the prototype objective under evaluation. The results are compared to a reference diagnosis of the same sample. More bacteria are counted in matched fields of view in digital images taken with the prototype objective than with the standard clinical microscope. All diagnostic results are found to be highly concordant. An array microscope built with this miniature lens design will be able to detect M tuberculosis with high sensitivity and specificity.

  1. MUDAL: a 4 pi multi-detector array in Lanzhou for charged particle detection at HIRFL

    CERN Document Server

    Li Song Lin; Jin Ge; Xu Hu Shan; Yin Xu; Wang Xiao Qiu; Li Zu Yu; Lu Jun

    2002-01-01

    A 4 pi multidetector array of measuring charged particle is described. It consists of 276 detector units, each unit composed of fast and slow plastic scintillator phoswiches, fast plastic scintillator and CsI(Tl) phoswiches and silicon detector telescopes. It covers geometrically 86% of the 4 pi solid angle and has very low detection thresholds. The detectors, operated under vacuum, is axially symmetric. sup 1 sup , sup 2 sup , sup 3 H, sup 3 sup , sup 4 He and the elements from Li to Ar can be identified and their energies measured over a large dynamic range

  2. Slant transform applied to electric power quality detection with field programmable gate array design enhanced

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Cheng-Tao [Dept. of Electrical Engineering, Kun Shan University, Tainan (China); Lin, Jeu-Min [Dept. of Electrical Engineering, Far East University, Tainan (China); Huang, Shyh-Jier [Dept. of Electrical Engineering, National Cheng Kung University, Tainan (China)

    2010-06-15

    In this paper, a slantlet transform is proposed with the field-programmable gate array (FPGA) hardware realization for electrical power system disturbance detection. By embedding the slantlet functions into wavelet basis, the method is anticipated to increase the capability of signal discrimination, hence improving the grasping the disturbance intrusion. Furthermore, with the hardware realization of FPGA chip, the practicality of the method can be better ensured. In order to validate the effectiveness of the proposed approach, several scenarios have been considered and verified with good agreement. (author)

  3. Highly sensitive label-free dual sensor array for rapid detection of wound bacteria.

    Science.gov (United States)

    Sheybani, Roya; Shukla, Anita

    2017-06-15

    Wound infections are a critical healthcare concern worldwide. Rapid and effective antibiotic treatments that can mitigate infection severity and prevent the spread of antibiotic resistance are contingent upon timely infection detection. In this work, dual electrochemical pH and cell-attachment sensor arrays were developed for the real-time spatial and temporal monitoring of potential wound infections. Biocompatible polymeric device coatings were integrated to stabilize the sensors and promote bacteria attachment while preventing non-specific cell and protein fouling. High sensitivity (bacteria concentration of 10(2) colony forming units (CFU)/mL and -88.1±6.3mV/pH over a pH range of 1-13) and stability over 14 days were achieved without the addition of biological recognition elements. The dual sensor array was demonstrated to successfully monitor the growth of both gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) over time through lag and log growth phases and following antibiotic administration and in simulated shallow wounds conditions. The versatile fabrication methods utilized in sensor development, superior sensitivity, prolonged stability, and lack of non-specific sensor fouling may enable long-term in situ sensor array operation in low resource settings. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Design and fabrication of a bidimentional microbolometer array for Terahertz detection characterized at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Orduna-Diaz, A [CIBA-Tlaxcala, IPN, Tlaxcala, Tlax.(Mexico); Castillo-DomInguez, E; Torres-Jacome, A; De la Hidalga-Wade, F J; Trevino-Palacios, C G, E-mail: abdu@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51 y 216, Puebla, Pue. 72000 (Mexico)

    2011-01-01

    We present the design, micromachining and characterization of a bidimentional bolometer array for radiation detection in the 0.7-1.5 THz frequency range. The detector is based on a boron doped amorphous silicon film (a-Si-B:H). The film optimized for sensitivity enhancement was obtained using 500 sccm diborane flow with 95 nm thickness. The sensing layer was deposited using plasma enhanced chemical vapor deposition (PECVD) technique at low frequency on a 0.45 {mu}m thick silicon nitride membrane sustained by a micromachined frame in crystalline silicon. The design consists of four 5x5 bolometer arrays made by conventional lithography. The bolometer active area is 660 {mu}m x 420 {mu}m and the detector will operate as a focal plane array. The current-voltage characteristics present an ohmic behaviour; the temperature coefficient of resistance (TCR) was obtained by measuring the bolometer performance from room temperature down to liquid nitrogen temperature. The responsivity was measured under illumination from a black body radiating at 300, 500, 700, 900 and 1100 deg. C, obtaining a value of R =1.17 x 10{sup -2} A/W with a dark current of 4.43 x 10{sup -9} A

  5. Development Toward a Ground-Based Interferometric Phased Array for Radio Detection of High Energy Neutrinos

    CERN Document Server

    Avva, J; Chesebro, T; Cremonisi, L; Deaconu, C; Gupta, A; Ludwig, A; Messino, W; Miki, C; Nichol, R; Oberla, E; Romero-Wolf, A; Saltzberg, D; Schlupf, C; Shipp, N; Varner, G; Vieregg, A G; Wissel, S A

    2016-01-01

    A promising method for further measurements of high energy neutrinos at the PeV scale and above is through an in-ice radio interferometric phased array, designed to look for Askaryan emission from neutrinos interacting in large volumes of glacial ice. Such a detector would be sensitive to two populations of neutrinos: the PeV-scale astrophysical neutrino flux recently detected by IceCube, and the predicted cosmogenic ultra-high energy (UHE) flux ($E>10^{17}$ eV). Characterizing these high energy neutrino populations is an important step toward understanding the most energetic cosmic accelerators, and the discovery of UHE neutrinos would allow us to probe fundamental physics at energy scales that are not achievable on Earth. We report here on studies validating the phased array technique, including measurements and a simulation of thermal noise correlations between nearby antennas, beamforming for impulsive signals, and a measurement of the expected improvement in trigger efficiency through the phased array te...

  6. The stochastic background: scaling laws and time to detection for pulsar timing arrays

    CERN Document Server

    Siemens, Xavier; Jenet, Fredrick; Romano, Joseph D

    2013-01-01

    We derive scaling laws for the signal-to-noise ratio of the optimal cross-correlation statistic, and show that the large power-law increase of the signal-to-noise ratio as a function of the the observation time $T$ that is usually assumed holds only at early times. After enough time has elapsed, pulsar timing arrays enter a new regime where the signal to noise only scales as $\\sqrt{T}$. In addition, in this regime the quality of the pulsar timing data and the cadence become relatively un-important. This occurs because the lowest frequencies of the pulsar timing residuals become gravitational-wave dominated. Pulsar timing arrays enter this regime more quickly than one might naively suspect. For T=10 yr observations and typical stochastic background amplitudes, pulsars with residual RMSs of less than about $1\\,\\mu$s are already in that regime. The best strategy to increase the detectability of the background in this regime is to increase the number of pulsars in the array. We also perform realistic simulations ...

  7. Low Frequency Gravitational Wave Detection With Ground Based Atom Interferometer Arrays

    CERN Document Server

    Chaibi, W; Canuel, B; Bertoldi, A; Landragin, A; Bouyer, P

    2016-01-01

    We propose a new detection strategy for gravitational waves (GWs) below few Hertz based on a correlated array of atom interferometers (AIs). Our proposal allows to reduce the Newtonian Noise (NN) which limits all ground based GW detectors below few Hertz, including previous atom interferometry-based concepts. Using an array of long baseline AI gradiometers yields several estimations of the NN, whose effect can thus be reduced via statistical averaging. Considering the km baseline of current optical detectors, a NN rejection of factor 2 could be achieved, and tested with existing AI array geometries. Exploiting the correlation properties of the gravity acceleration noise, we show that a 10-fold or more NN rejection is possible with a dedicated configuration. Considering a conservative NN model and the current developments in cold atom technology, we show that strain sensitivities below $1\\times 10^{-19}/ \\sqrt{\\text{Hz}}$ in the $ 0.3-3 \\ \\text{Hz}$ frequency band can be within reach, with a peak sensitivity o...

  8. Improved OAM-Based Radar Targets Detection Using Uniform Concentric Circular Arrays

    Directory of Open Access Journals (Sweden)

    Mingtuan Lin

    2016-01-01

    Full Text Available Without any relative moves or beam scanning, the novel Orbital-Angular-Momentum- (OAM- based radar targets detection technique using uniform concentric circular arrays (UCCAs shows the azimuthal estimation ability, which provides new perspective for radar system design. However, the main estimation method, that is, Fast Fourier Transform (FFT, under this scheme suffers from low resolution. As a solution, this paper rebuilds the OAM-based radar targets detection model and introduces the multiple signal classification (MUSIC algorithm to improve the resolution for detecting targets within the main lobes. The spatial smoothing technique is proposed to tackle the coherent problem brought by the proposed model. Analytical study and simulation demonstrate the superresolution estimation capacity the MUSIC algorithm can achieve for detecting targets within the main lobes. The performance of the MUSIC algorithm to detect targets not illuminated by the main lobes is further evaluated. Despite the fact that MUSIC algorithm loses the resolution advantage under this case, its estimation is more robust than that of the FFT method. Overall, the proposed MUSIC algorithm for the OAM-based radar system demonstrates the superresolution ability for detecting targets within the main lobes and good robustness for targets out of the main lobes.

  9. Detection of fast radio transients with multiple stations: a case study using the Very Long Baseline Array

    CERN Document Server

    Thompson, David R; Brisken, Walter; Deller, Adam T; Majid, Walid A; Tingay, Steven J; Wayth, Randall B

    2011-01-01

    Recent investigations reveal an important new class of transient radio phenomena that occur on sub-millisecond timescales. Often transient surveys' data volumes are too large to archive exhaustively. Instead, an on-line automatic system must excise impulsive interference and detect candidate events in real-time. This work presents a case study using data from multiple geographically distributed stations to perform simultaneous interference excision and transient detection. We present several algorithms that incorporate dedispersed data from multiple sites, and report experiments with a commensal real-time transient detection system on the Very Long Baseline Array (VLBA). We test the system using observations of pulsar B0329+54. The multiple-station algorithms enhanced sensitivity for detection of individual pulses. These strategies could improve detection performance for a future generation of geographically distributed arrays such as the Australian Square Kilometre Array Pathfinder and the Square Kilometre A...

  10. Real-time calibration of the AARTFAAC array for transient detection

    Science.gov (United States)

    Prasad, P.; Wijnholds, S. J.; Huizinga, F.; Wijers, R. A. M. J.

    2014-08-01

    The search for transient phenomena at low radio frequencies is now coming of age with the development of radio sky monitors with a large field of view, which are made feasible by new developments in calibration algorithms and computing. However, accurate calibration of such arrays is challenging, especially within the latency requirements of near real-time transient monitors, and is the main cause of limiting their sensitivities. This paper describes a strategy for real-time, wide-field direction-dependent calibration of the Amsterdam-ASTRON Radio Transients Facility and Analysis Center (AARTFAAC) array, which is a sensitive, continuously available all-sky monitor based on the LOw Frequency ARray (LOFAR). The monitor operates in a zenith pointing, snapshot imaging mode for image plane detection of bright radio transients. We show that a tracking calibration approach with solution propagation satisfies our latency, computing, and calibration accuracy constraints. We characterize the instrument and verify the calibration strategy under a variety of observing conditions. This brings out several phenomena, which can bias the calibration. The real-time nature of the application further imposes strict latency and computational constraints. We find that although ionosphere-induced phase errors present a major impediment to accurate calibration, these can be corrected in the direction of the brightest few sources to significantly improve image quality. Our real-time calibration pipeline implementation processes a single spectral channel of a snapshot observation in ~0.2 s on test hardware, which is well within its latency budget. Autonomously calibrating and imaging one second snapshots, our approach leads to a typical image noise of ~10 Jy for a ~90 kHz channel, reaching dynamic ranges of ~2000:1. We also show that difference imaging allows thermal-noise limited transient detection, despite the instrument being confusion-noise limited.

  11. Visual detection of 2,4,6-trinitrotolune by molecularly imprinted colloidal array photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Asher, Sanford A., E-mail: asher@pitt.edu [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Meng, Zihui, E-mail: m_zihui@yahoo.com [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Yan, Zequn [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Xue, Min, E-mail: minxue@bit.edu.cn [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Qiu, Lili, E-mail: qiulili@bit.edu.cn [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Yi, Da [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China)

    2016-10-05

    Graphical abstract: Molecularly imprinted colloidal array (MICA) was explored for the selective visual detection of TNT with color changing from green to red. And molecularly imprinted colloidal particles (MICs) were evaluated for the adsorption capacity and the imprinting efficiency. The MICA had excellent flexibility, reversibility and stability. It promised high potential for the visual semi-quantitative detection of other explosives. - Highlights: • Molecularly imprinted colloidal array (MICA) was used to visually detect TNT. • The relationship of particle size, diffracted wavelength and color was discussed. • The adsorption capacity and imprinting efficiency of MICs were calculated. • MICA had short response time, high selectivity, good reversibility and stability. • MICA had high potential to be used in other customed visual explosive detection. - Abstract: We developed a photonic crystal (PhC) sensor for the quantification of 2,4,6-trinitrotoluene (TNT) in solution. Monodisperse (210 nm in diameter) molecularly imprinted colloidal particles (MICs) for TNT were prepared by the emulsion polymerization of methyl methacrylate and acrylamide in the presence of TNT as a template. The MICs were then self-assembled into close-packed opal PhC films. The adsorption capacity of the MICs for TNT was 64 mg TNT/g. The diffraction from the PhC depended on the TNT concentration in a methanol/water (3/2, v/v) potassium dihydrogen phosphate buffer solution (pH = 7.0, 30 mM). The limit of detection (LOD) of the sensor was 1.03 μg. The color of the molecularly imprinted colloidal array (MICA) changed from green to red with an 84 nm diffraction red shift when the TNT concentration increased to 20 mM. The sensor response time was 3 min. The PhC sensor was selective for TNT compared to similar compounds such as 2,4,6-trinitrophenol, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2-nitromesitylene, 4-nitrotoluene, 2-nitrotoluene, 1,3-dinitrobenzene, methylbenzene, 4-nitrophenol

  12. Single-strand conformation polymorphism analysis using capillary array electrophoresis for large-scale mutation detection.

    Science.gov (United States)

    Larsen, Lars Allan; Jespersgaard, Cathrine; Andersen, Paal Skytt

    2007-01-01

    This protocol describes capillary array electrophoresis single-strand conformation polymorphism (CAE-SSCP), a screening method for detection of unknown and previously identified mutations. The method detects 98% of mutations in a sample material and can be applied to any organism where the goal is to determine genetic variation. This protocol describes how to screen for mutations in 192 singleplex or up to 768 multiplex samples over 3 days. The protocol is based on the principle of sequence-specific mobility of single-stranded DNA in a native polymer, and covers all stages in the procedure, from initial DNA purification to final CAE-SSCP data analysis, as follows: DNA is purified, followed by PCR amplification using fluorescent primers. After PCR amplification, double-stranded DNA is heat-denatured to separate the strands and subsequently cooled on ice to avoid reannealing. Finally, samples are analyzed by capillary electrophoresis and appropriate analysis software.

  13. High Sensitivity Terahertz Detection through Large-Area Plasmonic Nano-Antenna Arrays

    Science.gov (United States)

    Yardimci, Nezih Tolga; Jarrahi, Mona

    2017-01-01

    Plasmonic photoconductive antennas have great promise for increasing responsivity and detection sensitivity of conventional photoconductive detectors in time-domain terahertz imaging and spectroscopy systems. However, operation bandwidth of previously demonstrated plasmonic photoconductive antennas has been limited by bandwidth constraints of their antennas and photoconductor parasitics. Here, we present a powerful technique for realizing broadband terahertz detectors through large-area plasmonic photoconductive nano-antenna arrays. A key novelty that makes the presented terahertz detector superior to the state-of-the art is a specific large-area device geometry that offers a strong interaction between the incident terahertz beam and optical pump at the nanoscale, while maintaining a broad operation bandwidth. The large device active area allows robust operation against optical and terahertz beam misalignments. We demonstrate broadband terahertz detection with signal-to-noise ratio levels as high as 107 dB. PMID:28205615

  14. High Sensitivity Terahertz Detection through Large-Area Plasmonic Nano-Antenna Arrays

    Science.gov (United States)

    Yardimci, Nezih Tolga; Jarrahi, Mona

    2017-02-01

    Plasmonic photoconductive antennas have great promise for increasing responsivity and detection sensitivity of conventional photoconductive detectors in time-domain terahertz imaging and spectroscopy systems. However, operation bandwidth of previously demonstrated plasmonic photoconductive antennas has been limited by bandwidth constraints of their antennas and photoconductor parasitics. Here, we present a powerful technique for realizing broadband terahertz detectors through large-area plasmonic photoconductive nano-antenna arrays. A key novelty that makes the presented terahertz detector superior to the state-of-the art is a specific large-area device geometry that offers a strong interaction between the incident terahertz beam and optical pump at the nanoscale, while maintaining a broad operation bandwidth. The large device active area allows robust operation against optical and terahertz beam misalignments. We demonstrate broadband terahertz detection with signal-to-noise ratio levels as high as 107 dB.

  15. Lenslet Array to Further Suppress Star Light for Direct Exoplanet Detection

    Science.gov (United States)

    Gong, Qian; McElwain, Michael; Shiri, Ron

    2016-01-01

    Direct imaging plays a key role in the detection and characterization of exoplanets orbiting within its host star's habitable zone. Many innovative ideas for starlight suppression and wavefront control have been proposed and developed over the past decade. However, several technological challenges still lie ahead to achieve the required contrast, including controlling the observatory pointing performance, fabricating occulting masks with tight optical tolerances, developing wavefront control algorithms, controlling stray light, advancing single photon detecting detectors, and integrated system-level issues. This paper explores how a lenslet array and pinhole mask may be implemented to further suppress uncorrected starlight that leaks through the occulting mask. An external occulter, or star shade, is simulated to demonstrate this concept, although this approach can be implemented for internal coronagraphs as well. We describe how to use simple relay optics to control the scene near the inner working angle and the level of the suppression expected. Furthermore, if the lenslet array is the input to an integral field spectrograph, as planned for the WFIRST mission, the spectral content of the exoplanet atmospheres can be obtained to determine if the observed planet is habitable and ultimately, if it is inhabited.

  16. A Multiplex PCR-coupled Liquid Bead Array for the Simultaneous Detection of Four Biothreat Agents

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W J; Erler, A M; Nasarabadi, S L; Skowronski, E W; McCready, P M

    2004-02-04

    We have developed a 10-plexed PCR assay coupled to a 12-plexed liquid bead array to rapidly screen environmental samples for B. anthracis, Y. pestis, F. tularensis, and B. melitensis. Highly validated species -specific primer sets were used to simultaneously amplify multiple diagnostic regions unique to each individual pathogen. Resolution of the mix of amplified products was achieved by PCR product hybridization to corresponding probe sequences, attached to unique sets of fluorescent beads. The hybridized beads were processed through a flow cytometer, which detected presence and quantity of each PCR product. The assay was optimized to allow for maximum sensitivity in a multiplexed format. A high- throughput demonstration was performed where 384 simulated environmental samples were spiked with different amounts of B. thuringensis spores and pathogen DNA. The samples were robotically processed to extract DNA and arrayed for multiplexed PCR-liquid bead detection. The assay correctly identified the presence or absence of each pathogen and collected over 3,000 individual data points within a single 8-hour shift for approximately $1.20 per sample in a 10-plexed assay.

  17. Detection and Analysis of Low-Frequency Sperm Whale Vocalizations with a Towed Array

    Science.gov (United States)

    Bohn, Alexander

    Sperm whale vocalizations recorded during a sea test and calibration experiment in the Gulf of Maine on a single towed, horizontal, densely sampled, low-frequency (developed to achieve automatic detection of vocalizations. This analysis is shown to have potential utility despite restriction to only the low-frequency component of the vocalizations by sampling theory. In addition, transmission loss in the New England continental shelf and slope environment is accounted for with an ocean waveguide-acoustic propagation model. Multiple averaged realizations of this model are used to estimate transmission loss as a function of range and depth for transects between the receiver array and vocalizing whales. Comparison of the vocalizations and background noise levels and the estimated transmission loss suggests the sperm whale detection range after coherent array processing exceeds 60 km in low-to-moderate sea states. Low-frequency source levels of vocalizations are estimated using the received levels and the estimated transmission loss, and applications of both this estimate and the receiver-side statistics are discussed.

  18. Simultaneous detection of lactate and glucose by integrated printed circuit board based array sensing chip.

    Science.gov (United States)

    Li, Xuelian; Zang, Jianfeng; Liu, Yingshuai; Lu, Zhisong; Li, Qing; Li, Chang Ming

    2013-04-10

    An integrated printed circuit board (PCB) based array sensing chip was developed to simultaneously detect lactate and glucose in mouse serum. The novelty of the chip relies on a concept demonstration of inexpensive high-throughput electronic biochip, a chip design for high signal to noise ratio and high sensitivity by construction of positively charged chitosan/redox polymer Polyvinylimidazole-Os (PVI-Os)/carbon nanotube (CNT) composite sensing platform, in which the positively charged chitosan/PVI-Os is mediator and electrostatically immobilizes the negatively charged enzyme, while CNTs function as an essential cross-linker to network PVI-Os and chitosan due to its negative charged nature. Additional electrodes on the chip with the same sensing layer but without enzymes were prepared to correct the interferences for high specificity. Low detection limits of 0.6 μM and 5 μM were achieved for lactate and glucose, respectively. This work could be extended to inexpensive array sensing chips with high sensitivity, good specificity and high reproducibility for various sensor applications.

  19. Implementing Silicon Nanoribbon Field-Effect Transistors as Arrays for Multiple Ion Detection

    Directory of Open Access Journals (Sweden)

    Ralph L. Stoop

    2016-05-01

    Full Text Available Ionic gradients play a crucial role in the physiology of the human body, ranging from metabolism in cells to muscle contractions or brain activities. To monitor these ions, inexpensive, label-free chemical sensing devices are needed. Field-effect transistors (FETs based on silicon (Si nanowires or nanoribbons (NRs have a great potential as future biochemical sensors as they allow for the integration in microscopic devices at low production costs. Integrating NRs in dense arrays on a single chip expands the field of applications to implantable electrodes or multifunctional chemical sensing platforms. Ideally, such a platform is capable of detecting numerous species in a complex analyte. Here, we demonstrate the basis for simultaneous sodium and fluoride ion detection with a single sensor chip consisting of arrays of gold-coated SiNR FETs. A microfluidic system with individual channels allows modifying the NR surfaces with self-assembled monolayers of two types of ion receptors sensitive to sodium and fluoride ions. The functionalization procedure results in a differential setup having active fluoride- and sodium-sensitive NRs together with bare gold control NRs on the same chip. Comparing functionalized NRs with control NRs allows the compensation of non-specific contributions from changes in the background electrolyte concentration and reveals the response to the targeted species.

  20. Trace detection of dissolved hydrogen gas in oil using a palladium nanowire array.

    Science.gov (United States)

    Yang, Fan; Jung, Dongoh; Penner, Reginald M

    2011-12-15

    The electrical resistance, R, of an array of 30 palladium nanowires is used to detect the concentration of dissolved hydrogen gas (H(2)) in transformer oil over the temperature range from 21 to 70 °C. The palladium nanowire array (PdNWA), consisting of Pd nanowires ∼100 nm (width), ∼20 nm (height), and 100 μm (length), was prepared using the lithographically patterned nanowire electrodeposition (LPNE) method. The R of the PdNWA increased by up to 8% upon exposure to dissolved H(2) at concentrations above 1.0 ppm and up to 2940 ppm at 21 °C. The measured limit-of-detection for dissolved H(2) was 1.0 ppm at 21 °C and 1.6 ppm at 70 °C. The increase in resistance induced by exposure to H(2) was linear with [H(2)](oil)(1/2) across this concentration range. A PdNWA sensor operating in flowing transformer oil has functioned continuously for 150 days.

  1. High sensitive immunoassay for multiplex mycotoxin detection with photonic crystal microsphere suspension array.

    Science.gov (United States)

    Deng, Guozhe; Xu, Kun; Sun, Yue; Chen, Yu; Zheng, Tiesong; Li, Jianlin

    2013-03-05

    A novel, sensitive, and high throughput competitive immunoassay for multiplex mycotoxins was established by immobilizing the artificial antigens (Ags) of mycotoxins on the surfaces of three kinds of silica photonic crystal microsphere (SPCM) suspension arrays. The SPCMs were encoded by their reflectance peak positions. Aflatoxin B1 (AFB1), fumonisin B1 (FB1), and citrinin (CIT) spiked in the cereals were extracted, and the fluorescein isothiocyanate (FITC) labeled antibodies (Abs) of these mycotoxins were added into the centrifuge tube which contained the SPCMs of the modified artificial antigens (Ags). The fluorescence signal was collected by an array fluorescent scanner. The limit of detection (LOD) was as low as 0.5, 1, and 0.8 pg/mL for AFB1, FB1, and CIT, respectively. The new method provided a wide linear detection range from 0.001 to 10, 0.001 to 10, and 0.001 to 1 ng/mL for AFB1, FB1, and CIT, respectively. The mean recovery rates are in range of 74.7 ± 4.0% to 127.9 ± 4.4% for the three mycotoxins in corn, peanuts, and wheat. The developed method for mycotoxins was used to assay the AFB1, FB1, and CIT level in 10 naturally contaminated cereal samples, and the results of detection were in agreement with that of a classic enzyme-linked immunosorbent assay (ELISA) method. This method saves a large amount of reagents (10 μL volume) and detection time (<3 h) for multiplex mycotoxin assay.

  2. Simplified design of the coulometric sensor-actuator system by the application of a time-dependent actuator current

    OpenAIRE

    1992-01-01

    Acid or base concentrations can be determined by performing an acid-base titration with coulometrically generated OH¿ or H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. It is shown, both theoretically and experimentally, that the relation between the acid or base concentration and the time needed to reach the equivalence point in the resulting titration curve is linear in the case where the current through the actuator electrode varies with...

  3. Coulometric bioelectrocatalytic reactions based on NAD-dependent dehydrogenases in tricarboxylic acid cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Jun [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Tsujimura, Seiya [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: seiya@kais.kyoto-u.ac.jp; Kano, Kenji [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: kkano@kais.kyoto-u.ac.jp

    2008-12-30

    This paper describes the characterization of mediated electro-enzymatic electrolysis systems based on NAD-dependent dehydrogenase reactions in the tricarboxylic acid (TCA) cycle. A micro-bulk electrolysis system with a carbon felt anode immersed in an electrolysis solution with a value of about 10 {mu}L was constructed for coulometric analysis of the substrate oxidation. Diaphorase (DI) was used to couple the NAD-dependent dehydrogenase reaction with the anode reaction of a suitable redox mediator. We focused on three types of NAD-dependant dehydrogenases reactions in this research: (1) isocitrate oxidation, in which the standard Gibbs energy change ({delta}G{sup o}') is negative; (2) {alpha}-ketoglutarate oxidation, which involves an electrochemically active coenzyme A (CoA); and (3) malate oxidation, which is thermodynamically unfavorable because of a large positive {delta}G{sup o}' value. The complete electrolysis of isocitrate was easily achieved, supporting the effective re-oxidation of NADH in the diaphorase-catalyzed electrochemical reaction. CoA was unfavorably oxidized at the electrodes in the presence of some mediators. The electrocatalytic oxidation of CoA was suppressed and the quantitative electrochemical oxidation of {alpha}-ketoglutarate was achieved by selecting a suitable mediator with negligibly slow electron transfer kinetics with CoA. The uphill malate oxidation was susceptible to product inhibition in the bioelectrochemical system, although NADH generated in the malate dehydrogenase reaction was immediately oxidized in the electrochemical system. The inhibition was successfully suppressed by linking citrate synthase to quench oxaloacetate and to make the total {delta}G{sup o}' value negative.

  4. Simultaneous and rapid detection of multiple pesticide and veterinary drug residues by suspension array technology.

    Science.gov (United States)

    Liu, Nan; Gao, Zhixian; Ma, Hongwei; Su, Pu; Ma, Xinhua; Li, Xiaoli; Ou, Guorong

    2013-03-15

    Suspension array technology is proposed for the simultaneous quantitative determination of seven kinds of pesticide and veterinary drug residues, namely, atrazine, chloramphenicol, carbaryl, clenbuterol, 17-β-estradiol, imidacloprid, and tylosin. The assay is simple and can be accomplished within 2h without repeated pumping and washing steps unlike conventional suspension arrays. The hapten-protein conjugate-coated beads bind to their complementary biotinylated antibodies using a competitive immunoassay format. The coefficients of determination R(2) for six targets were greater than 0.992, whereas that for atrazine was 0.961, which indicate good logistic correlations. The dynamic ranges for the seven targets in the 7-plex assay ranged from 2 log units to 4 log units(1.60×10(0)-1.64×10(3), 5.12×10(-2)-1.60×10(2), 1.00×10(0)-3.13×10(3), 4.00×10(-1)-4.10×10(2), 4.00×10(-1)-4.10×10(2), 5.12×10(-2)-1.60×10(2), and 2.00×10(0)-4.00×10(2)ngmL(-1)). The minimum detection concentrations of chloramphenicol, carbaryl, clenbuterol and 17-β-estradiol in the suspension array (0.05, 1.00, 0.40 and 0.40 ng mL(-1)) were lower than the corresponding limits of detection (0.25, 6.60, 24.23 and 13.96 ng mL(-1)) of using an indirect competitive enzyme-linked immunosorbent assay. Environmental scanning electron microscope was employed to characterize the bead surface, which directly confirmed the reactions on the beads. The suspension array is more flexible and feasible than ELISA for the fast quantitative analysis of pesticide and veterinary drug residues. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Mass-sensing BioCD Protein Array towards Clinical Application: Prostate Specific Antigen Detection in Patient Sera

    CERN Document Server

    Wang, Xuefeng; Nolte, David D; Ratliff, Timothy L

    2009-01-01

    Mass-sensing biosensor arrays for protein detection require no fluorophores or enzyme labels. However, few mass biosensor protein arrays have demonstrated successful application in high background samples, such as serum. In this paper, we test the BioCD as a mass biosensor based on optical interferometry of antibodies covalently attached through Schiff-base reduction. We use the BioCD to detect prostate specific antigen (PSA, a biomarker of prostate cancer) in patient sera in a 96-well anti-PSA microarray. We have attained a 4 ng/ml detection limit in full serum and have measured PSA concentrations in three patient sera.

  6. Colorimetric sensor array allows fast detection and simultaneous identification of sepsis-causing bacteria in spiked blood culture.

    Science.gov (United States)

    Lim, Sung H; Mix, Samantha; Xu, Zeyu; Taba, Brian; Budvytiene, Indre; Berliner, Anders N; Queralto, Nuria; Churi, Yair S; Huang, Richard S; Eiden, Michael; Martino, Raymond A; Rhodes, Paul; Banaei, Niaz

    2014-02-01

    Sepsis is a medical emergency demanding early diagnosis and tailored antimicrobial therapy. Every hour of delay in initiating effective therapy measurably increases patient mortality. Blood culture is currently the reference standard for detecting bloodstream infection, a multistep process which may take one to several days. Here, we report a novel paradigm for earlier detection and the simultaneous identification of pathogens in spiked blood cultures by means of a metabolomic "fingerprint" of the volatile mixture outgassed by the organisms. The colorimetric sensor array provided significantly faster detection of positive blood cultures than a conventional blood culture system (12.1 h versus 14.9 h, P detection. The colorimetric sensor array also allowed for discrimination between unrelated strains of methicillin-resistant Staphylococcus aureus, indicating that the metabolomic fingerprint has the potential to track nosocomial transmissions. Altogether, the colorimetric sensor array is a promising tool that offers a new paradigm for diagnosing bloodstream infections.

  7. A Pt-doped TiO2 nanotube arrays sensor for detecting SF6 decomposition products.

    Science.gov (United States)

    Zhang, Xiaoxing; Tie, Jing; Zhang, Jinbin

    2013-10-30

    The detection of partial discharge and analysis of SF6 gas components in gas-insulated switchgear (GIS) is important for the diagnosis and operating state assessment of power equipment. The use of a Pt-doped TiO2 nanotube arrays sensor for detecting sulfur hexafluoride (SF6) decomposition products is proposed in this paper. The electrochemical pulse deposition method is employed to prepare the sensor array. The sensor's response to the main characteristic gaseous decomposition products of SF6 is evaluated. The gas sensing characteristic curves of the Pt-doped TiO2 nanotube sensor and intrinsic TiO2 nanotube arrays sensor are compared. The mechanism of the sensitive response is discussed. Test results showed that the Pt-doped nanoparticles not only change the gas sensing selectivity of the TiO2 nanotube arrays sensor with respect to the main characteristic SF6 decomposition products, but also reduce the operating temperature of the sensor.

  8. Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept

    Science.gov (United States)

    Gordley, Larry L.; McHugh, Martin J.; Marshall, B. T.; Thompson, Earl

    2009-05-01

    The Digital Array Gas Radiometer (DAGR) concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR) for remote trace gas detection and monitoring. GFCR sensors have been successful in many infrared remote sensing applications. Historically however, solar backscatter measurements have not been as successful because instrument designs have been susceptible to natural variations in surface albedo, which induce clutter and degrade the sensitivity. DAGR overcomes this limitation with several key innovations. First, a pupil imaging system scrambles the received light, removing nearly all spatial clutter and permitting a small calibration source to be easily inserted. Then, by using focal plane arrays rather than single detectors to collect the light, dramatic advances in dynamic range can be achieved. Finally, when used with the calibration source, data processing approaches can further mitigate detector non-uniformity effects. DAGR sensors can be made as small as digital cameras and are well suited for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Easily integrated into a satellite platform, a space-based DAGR would provide near-global sensing of climatically important species such as such as CO, CH4, and N2O. Aircraft and UAV measurements with a DAGR could be used to monitor agricultural and industrial emissions. Ground-based or portable DAGRs could augment early warning systems for chemical weapons or toxic materials. Finally, planetary science applications include detection and mapping of biomarkers such as CH4 in the Martian atmosphere.

  9. Bimetallic gold-silver nanoplate array as a highly active SERS substrate for detection of streptavidin/biotin assemblies.

    Science.gov (United States)

    Bi, Liyan; Dong, Jian; Xie, Wei; Lu, Wenbo; Tong, Wei; Tao, Lin; Qian, Weiping

    2013-12-17

    The silver-modified gold nanoplate arrays as bimetallic surface-enhanced Raman scattering (SERS) substrates were optimized for the surface-enhanced Raman detection of streptavidin/biotin monolayer assemblies. The bimetallic gold-silver nanoplate arrays were fabricated by coating silver nanoparticles uniformly on the gold nanoplate arrays. Depending on silver nanoparticle coating, the localized surface plasmon resonance (LSPR) peak of the bimetallic gold-silver nanoplate arrays blue-shifted and broadened significantly. The common probe molecule, Niel Blue A sulfate (NBA) was used for testing the SERS activity of the bimetallic gold-silver nanoplate arrays. The SERS intensity increased with the silver nanoparticle coating, due to a large number of hot spots and nanoparticle interfaces. The platforms were tested against a monolayer of streptavidin functionalized over the bimetallic gold-silver nanoplate arrays showing that good quality spectra could be acquired with a short acquisition time. The supramolecular interaction between streptavidin (strep) and biotin showed subsequent modification of Raman spectra that implied a change of the secondary structure of the host biomolecule. And the detection concentration for biotin by this method was as low as 1.0 nM. The enhanced SERS performance of such bimetallic gold-silver nanoplate arrays could spur further interest in the integration of highly sensitive biosensors for rapid, nondestructive, and quantitative bioanalysis, particularly in microfluidics.

  10. Pupil and Glint Detection Using Wearable Camera Sensor and Near-Infrared LED Array.

    Science.gov (United States)

    Wang, Jianzhong; Zhang, Guangyue; Shi, Jiadong

    2015-12-02

    This paper proposes a novel pupil and glint detection method for gaze tracking system using a wearable camera sensor and near-infrared LED array. A novel circular ring rays location (CRRL) method is proposed for pupil boundary points detection. Firstly, improved Otsu optimal threshold binarization, opening-and-closing operation and projection of 3D gray-level histogram are utilized to estimate rough pupil center and radius. Secondly, a circular ring area including pupil edge inside is determined according to rough pupil center and radius. Thirdly, a series of rays are shot from inner to outer ring to collect pupil boundary points. Interference points are eliminated by calculating gradient amplitude. At last, an improved total least squares is proposed to fit collected pupil boundary points. In addition, the improved total least squares developed is utilized for the solution of Gaussian function deformation to calculate glint center. The experimental results show that the proposed method is more robust and accurate than conventional detection methods. When interference factors such as glints and natural light reflection are located on pupil contour, pupil boundary points and center can be detected accurately. The proposed method contributes to enhance stability, accuracy and real-time quality of gaze tracking system.

  11. Microfluidic Arrayed Lab-On-A-Chip for Electrochemical Capacitive Detection of DNA Hybridization Events.

    Science.gov (United States)

    Ben-Yoav, Hadar; Dykstra, Peter H; Bentley, William E; Ghodssi, Reza

    2017-01-01

    A microfluidic electrochemical lab-on-a-chip (LOC) device for DNA hybridization detection has been developed. The device comprises a 3 × 3 array of microelectrodes integrated with a dual layer microfluidic valved manipulation system that provides controlled and automated capabilities for high throughput analysis of microliter volume samples. The surface of the microelectrodes is functionalized with single-stranded DNA (ssDNA) probes which enable specific detection of complementary ssDNA targets. These targets are detected by a capacitive technique which measures dielectric variation at the microelectrode-electrolyte interface due to DNA hybridization events. A quantitative analysis of the hybridization events is carried out based on a sensing modeling that includes detailed analysis of energy storage and dissipation components. By calculating these components during hybridization events the device is able to demonstrate specific and dose response sensing characteristics. The developed microfluidic LOC for DNA hybridization detection offers a technology for real-time and label-free assessment of genetic markers outside of laboratory settings, such as at the point-of-care or in-field environmental monitoring.

  12. Luminex(®) multiplex bead suspension arrays for the detection and serotyping of Salmonella spp.

    Science.gov (United States)

    Dunbar, Sherry A; Ritchie, Vivette Brown; Hoffmeyer, Michaela R; Rana, Gunjot S; Zhang, Hongwei

    2015-01-01

    In this chapter we describe two commercially available bead-based molecular assays for detection, identification and serotyping of Salmonella. The xTAG(®) Gastrointestinal Pathogen Panel (GPP) is a qualitative multiplex test for the simultaneous detection of nucleic acids from Salmonella plus 14 other gastroenteritis-causing bacteria, viruses, and parasites from stool specimens. xTAG GPP uses the Luminex(®) xTAG universal array technology for the identification of specific target sequences combined with the xMAP(®) bead multiplexing platform for detection of the targets that were present in the starting sample. The xMAP Salmonella Serotyping Assay (SSA) is a multiplex nucleic acid-based direct hybridization assay for molecular identification of the serotype of Salmonella isolates. In xMAP SSA, target sequences amplified from cultured Salmonella isolates are captured by hybridization to sequence-specific capture probes which have been coupled to the multiplexed bead sets. Herein we provide detailed protocols for each of these assays and present data which describe their performance characteristics for detection and serotyping Salmonella.

  13. Innovative optical power detection array system for relative positioning of inner-formation flying system

    Science.gov (United States)

    Hou, Zhendong; Wang, Zhaokui; Zhang, Yulin

    2016-09-01

    The Inner-formation flying system (IFFS) is conceived to feature a spherical proof mass falling freely within a large cavity for space gravity detection, of which first application focuses on the Earth's gravity field recovery. For the IFFS, it is the relative position of the proof mass to its surrounding cavity that is feedback into thrusters for tracking control, even as part of data to detect gravity. Since the demonstration and verification of demanding technologies using small satellite platforms is a very sensible choice prior to detection mission, an optical power detection array system (OPDAS) is proposed to measure the relative position with advantages of low cost and high adaptability. Besides that, its large dynamic range can reduce the requirement for satellite platform and releasing mechanism, which is also an attracting trait for small satellite application. The concept of the OPDAS is firstly presented, followed by the algorithm to position the proof mass. Then the radiation pressure caused by the measuring beam is modeled, and its disturbance on the proof mass is simulated. The experimental system to test the performance of a prototype of the OPDAS is established, and the preliminary results show that a precision of less than 0.4 mm across a dynamic range of several centimeters can be reached by the prototype of the OPDAS.

  14. Integrated Detection, Tracking, and Recognition of Faces with Omnivideo Array in Intelligent Environments

    Directory of Open Access Journals (Sweden)

    Mohan M. Trivedi

    2008-04-01

    Full Text Available We present a multilevel system architecture for intelligent environments equipped with omnivideo arrays. In order to gain unobtrusive human awareness, real-time 3D human tracking as well as robust video-based face detection and tracking and face recognition algorithms are needed. We first propose a multiprimitive face detection and tracking loop to crop face videos as the front end of our face recognition algorithm. Both skin-tone and elliptical detections are used for robust face searching, and view-based face classification is applied to the candidates before updating the Kalman filters for face tracking. For video-based face recognition, we propose three decision rules on the facial video segments. The majority rule and discrete HMM (DHMM rule accumulate single-frame face recognition results, while continuous density HMM (CDHMM works directly with the PCA facial features of the video segment for accumulated maximum likelihood (ML decision. The experiments demonstrate the robustness of the proposed face detection and tracking scheme and the three streaming face recognition schemes with 99% accuracy of the CDHMM rule. We then experiment on the system interactions with single person and group people by the integrated layers of activity awareness. We also discuss the speech-aided incremental learning of new faces.

  15. Integrated Detection, Tracking, and Recognition of Faces with Omnivideo Array in Intelligent Environments

    Directory of Open Access Journals (Sweden)

    Huang KohsiaS

    2008-01-01

    Full Text Available Abstract We present a multilevel system architecture for intelligent environments equipped with omnivideo arrays. In order to gain unobtrusive human awareness, real-time 3D human tracking as well as robust video-based face detection and tracking and face recognition algorithms are needed. We first propose a multiprimitive face detection and tracking loop to crop face videos as the front end of our face recognition algorithm. Both skin-tone and elliptical detections are used for robust face searching, and view-based face classification is applied to the candidates before updating the Kalman filters for face tracking. For video-based face recognition, we propose three decision rules on the facial video segments. The majority rule and discrete HMM (DHMM rule accumulate single-frame face recognition results, while continuous density HMM (CDHMM works directly with the PCA facial features of the video segment for accumulated maximum likelihood (ML decision. The experiments demonstrate the robustness of the proposed face detection and tracking scheme and the three streaming face recognition schemes with 99% accuracy of the CDHMM rule. We then experiment on the system interactions with single person and group people by the integrated layers of activity awareness. We also discuss the speech-aided incremental learning of new faces.

  16. Detecting super-Nyquist-frequency gravitational waves using a pulsar timing array

    CERN Document Server

    Yi, S -X

    2016-01-01

    The maximum frequency of gravitational waves (GWs) detectable with traditional pulsar timing methods is set by the Nyquist frequency ($f_{\\rm{Ny}}$) of the observation. Beyond this frequency, GWs leave no temporal-correlated signals; instead, they appear as white noise in the timing residuals. The variance of the GW-induced white noise is a function of the position of the pulsars relative to the GW source. By observing this unique functional form in the timing data, we propose that we can detect GWs of frequency $>$ $f_{\\rm{Ny}}$ (super-Nyquist frequency GWs; SNFGWs). We demonstrate the feasibility of the proposed method with simulated timing data. Using a selected dataset from the Parkes Pulsar Timing Array data release 1 and the North American Nanohertz Observatory for Gravitational Waves publicly available datasets, we try to detect the signals from single SNFGW sources. The result is consistent with no GW detection with 65.5\\% probability. An all-sky map of the sensitivity of the selected pulsar timing ar...

  17. Detection of mitochondrial DNA with the compact bead array sensor system (cBASS)

    Science.gov (United States)

    Mulvaney, Shawn P.; Ibe, Carol N.; Caldwell, Jane M.; Levine, Jay F.; Whitman, Lloyd J.; Tamanaha, Cy R.

    2009-02-01

    Enteric pathogens are a significant contaminant in surface waters used for recreation, fish and shellfish harvesting, crop irrigation, and human consumption. The need for water monitoring becomes more pronounced when industrial, agricultural, and residential lands are found in close proximity. Fecal contamination is particularly problematic and identification of the pollution source essential to remediation efforts. Standard monitoring for fecal contamination relies on indicator organisms, but the technique is too broad to identify the source of contamination. Instead, real-time PCR of mitochondrial DNA (mtDNA) is an emerging method for identification of the contamination source. Presented herein, we evaluate an alternative technology, the compact Bead Array Sensor System (cBASS®) and its assay approach Fluidic Force Discrimination (FFD), for the detection of mtDNA. Previously, we achieved multiplexed, attomolar detection of toxins and femtomolar detection of nucleic acids in minutes with FFD assays. More importantly, FFD assays are compatible with a variety of complex matrices and therefore potentially applicable for samples where the matrix would interfere with PCR amplification. We have designed a triplex assay for the NADH gene found in human, swine, and bovine mtDNA and demonstrated the specific detection of human mtDNA spiked into a waste water sample.

  18. Insertional translocation detected using FISH confirmation of array-comparative genomic hybridization (aCGH) results.

    Science.gov (United States)

    Kang, Sung-Hae L; Shaw, Chad; Ou, Zhishuo; Eng, Patricia A; Cooper, M Lance; Pursley, Amber N; Sahoo, Trilochan; Bacino, Carlos A; Chinault, A Craig; Stankiewicz, Pawel; Patel, Ankita; Lupski, James R; Cheung, Sau Wai

    2010-05-01

    Insertional translocations (ITs) are rare events that require at least three breaks in the chromosomes involved and thus qualify as complex chromosomal rearrangements (CCR). In the current study, we identified 40 ITs from approximately 18,000 clinical cases (1:500) using array-comparative genomic hybridization (aCGH) in conjunction with fluorescence in situ hybridization (FISH) confirmation of the aCGH findings, and parental follow-up studies. Both submicroscopic and microscopically visible IT events were detected. They were divided into three major categories: (1) simple intrachromosomal and interchromosomal IT resulting in pure segmental trisomy, (2) complex IT involving more than one abnormality, (3) deletion inherited from a parent with a balanced IT resulting in pure segmental monosomy. Of the cases in which follow-up parental studies were available, over half showed inheritance from an apparently unaffected parent carrying the same unbalanced rearrangement detected in the propositi, thus decreasing the likelihood that these IT events are clinically relevant. Nevertheless, we identified six cases in which small submicroscopic events were detected involving known disease-associated genes/genomic segments and are likely to be pathogenic. We recommend that copy number gains detected by clinical aCGH analysis should be confirmed using FISH analysis whenever possible in order to determine the physical location of the duplicated segment. We hypothesize that the increased use of aCGH in the clinic will demonstrate that IT occurs more frequently than previously considered but can identify genomic rearrangements with unclear clinical significance.

  19. Possible Gamma-Ray Burst radio detections by the Square Kilometre Array. New perspectives

    CERN Document Server

    Ruggeri, Alan Cosimo

    2016-01-01

    The next generation interferometric radio telescope, the Square Kilometre Array (SKA), which will be the most sensitive and largest radio telescope ever constructed, could greatly contribute to the detection, survey and characterization of Gamma Ray Bursts (GRBs). By the SKA, it will be possible to perform the follow up of GRBs even for several months. This approach would be extremely useful to extend the Spectrum Energetic Distribution (SED) from the gamma to the to radio band and would increase the number of radio detectable GRBs. In principle, the SKA could help to understand the physics of GRBs by setting constraints on theoretical models. This goal could be achieved by taking into account multiple observations at different wavelengths in order to obtain a deeper insight of the sources. Here, we present an estimation of GRB radio detections, showing that the GRBs can really be observed by the SKA. The approach that we present consists in determining blind detection rates derived by a very large sample con...

  20. A high-throughput method for GMO multi-detection using a microfluidic dynamic array.

    Science.gov (United States)

    Brod, Fábio Cristiano Angonesi; van Dijk, Jeroen P; Voorhuijzen, Marleen M; Dinon, Andréia Zilio; Guimarães, Luis Henrique S; Scholtens, Ingrid M J; Arisi, Ana Carolina Maisonnave; Kok, Esther J

    2014-02-01

    The ever-increasing production of genetically modified crops generates a demand for high-throughput DNA-based methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the number of GMOs that is potentially present in an individual sample. The present work presents the results of an innovative approach in genetically modified crops analysis by DNA based methods, which is the use of a microfluidic dynamic array as a high throughput multi-detection system. In order to evaluate the system, six test samples with an increasing degree of complexity were prepared, preamplified and subsequently analysed in the Fluidigm system. Twenty-eight assays targeting different DNA elements, GM events and species-specific reference genes were used in the experiment. The large majority of the assays tested presented expected results. The power of low level detection was assessed and elements present at concentrations as low as 0.06 % were successfully detected. The approach proposed in this work presents the Fluidigm system as a suitable and promising platform for GMO multi-detection.

  1. Low-frequency phased-array 2D fluorescence localization in breast cancer detection

    Science.gov (United States)

    Liu, Qian; Chen, Yu; Chance, Britton; Luo, Qingming

    2003-12-01

    A method for rapid, non-invasive 2D fluorescence localization of breast cancer using low frequency phased array near-infrared technique is presented in this article. In our study, we have developed a dual-channel fluorescence detection system to locate breast cancer. This system consists two pair of in-phase and out-of-phase light emitting diodes (LEDs) as the light sources and Photomultiplier Tube (PMT) as the detector. Two null planes generated by cancellation of diffusion photon density waves (DPDW) will indicate the 2D position of breast cancer with exogenous contrast agents. The fluorescent contrast agent used in this study is Indocyanine Green (ICG) and the minimum amount of ICG detected by our system is 0.5 μM. With the 2 cm separation of sources and detector, the maximum depth our system can detect is 10 mm. The whole system is in compact size and portable. Phantom experiments show that the system can provide real time detection and localization of small hidden absorbing-fluorescent objects inside the highly scattering medium with high accuracy of +/-3 mm. The potential application is that it is low-cost and can be used for breast cancer localization as operation aid and self-examination.

  2. Pupil and Glint Detection Using Wearable Camera Sensor and Near-Infrared LED Array

    Directory of Open Access Journals (Sweden)

    Jianzhong Wang

    2015-12-01

    Full Text Available This paper proposes a novel pupil and glint detection method for gaze tracking system using a wearable camera sensor and near-infrared LED array. A novel circular ring rays location (CRRL method is proposed for pupil boundary points detection. Firstly, improved Otsu optimal threshold binarization, opening-and-closing operation and projection of 3D gray-level histogram are utilized to estimate rough pupil center and radius. Secondly, a circular ring area including pupil edge inside is determined according to rough pupil center and radius. Thirdly, a series of rays are shot from inner to outer ring to collect pupil boundary points. Interference points are eliminated by calculating gradient amplitude. At last, an improved total least squares is proposed to fit collected pupil boundary points. In addition, the improved total least squares developed is utilized for the solution of Gaussian function deformation to calculate glint center. The experimental results show that the proposed method is more robust and accurate than conventional detection methods. When interference factors such as glints and natural light reflection are located on pupil contour, pupil boundary points and center can be detected accurately. The proposed method contributes to enhance stability, accuracy and real-time quality of gaze tracking system.

  3. Detection of Reflected Waves from Plate Boundary Using ACROSS Source and Seismic Array

    Science.gov (United States)

    Soma, T.; Watanabe, T.; Ikuta, R.; Saiga, A.; Miyajima, R.; Yamaoka, K.; Tsuruga, K.; Kunitomo, T.; Hasada, Y.; Kasahara, J.; Satomura, M.; Kumazawa, M.; Fujii, N.

    2005-12-01

    ACROSS (Accurately Controlled and Routinely Operated Signal System) is effective in monitoring temporary changes of Earth's interior. A long-term operation experiment near Nojima fault [Ikuta et al.,2004] detected small temporary changes of travel time of P and S waves at tele-seismic events. Toward Tokai monitoring plan to detect the reflected phases from the top of Philippine Sea Plate and monitor its temporal changes, a mid-term continuous experiment was conducted using ACROSS source and a seismic array. The experiment was operated for the period from Dec. 2004 to Sep.2005 in the Tokai area, Pacific side of the central part of Japan. In this region, the expected Tokai earthquake is a serious concern. In addition, slow slip events and low-frequency tremors are observed in this area. A strong reflected phase from the plate boundary was found by the seismic observation using artificial sources [Iidaka et al.,2003]. The purpose of the experiment is to establish a method to detect and monitor the reflection from the plate boundary using ACROSS. The ACROSS source is located in Toki city and operated by Tono Geoscience Center. The ACROSS source continuously transmits precisely-controlled frequency-modulated signals whose frequency band ranges from 10 to 20 Hz with an interval of 50 seconds. We deployed a short-span seismic array at the distance of 55 km from the ACROSS source. The cross-shaped seismic array spanning 2 km consists of 12 seismometers equipped with an offline data logger, amplifier and solarpanel. We stacked the received signal for a month with an interval of 200 seconds in order to improve signal noise ratio. We extracted a series of line spectrum of ACROSS signal. Transfer function can be obtained by dividing spectrum by the source. Applying inverse Fourier transform, we can obtain the transfer function in time-domain. We identified direct P and S phases by comparing with the standard travel time table by JMA. We also found some coherent later phases

  4. 6-Plex microsphere immunoassay with imaging planar array detection for mycotoxins in barley.

    Science.gov (United States)

    Peters, Jeroen; Cardall, Alice; Haasnoot, Willem; Nielen, Michel W F

    2014-08-21

    Mycotoxins are produced by fungi as secondary metabolites. They often multi-contaminate food and feed commodities posing a health risk to humans and animals. A fast and easy to apply multiplex screening of these commodities could be useful to detect multi-contamination. For this, we developed a semi-quantitative 6-plex immunoassay using a suspension array of paramagnetic colour-coded microspheres combined with imaging planar array detection for the mycotoxins aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, T2-toxin, HT-2 toxin and fumonisin B1. Mycotoxin specific monoclonal antibodies were coupled to different sets of microspheres and mycotoxins conjugated to the fluorescent protein R-phycoerythrin served as reporter molecules. Competition between free mycotoxins in the sample and mixed reporter molecules for antibody binding sites on mixed microspheres created a multiplex direct inhibition immunoassay. The reagents were selected for no or low cross-interactions between the assays and cross-reactions with metabolites and possible masked forms were determined. A within-laboratory validation was carried out using blank and spiked barley samples. Furthermore, the 6-plex was used to screen available barley, and malted barley, reference materials. The validation showed very high inter and intra-day precision for all samples with a maximum relative standard deviation value of 10%. The screening assay allows easy and rapid multiplex detection of the target mycotoxins in barley according to EU legislation. With a cut off factor of 50%, based on the EU maximum levels, we were able to screen at 2 μg kg(-1) for aflatoxin B1, 2.5 μg kg(-1) for ochratoxin A, 625 μg kg(-1) for deoxynivalenol, 50 μg kg(-1) for zearalenone, 1000 μg kg(-1) for fumonisin B1 and 25 μg kg(-1) for T-2 toxin. Thanks to the transportable planar array system, the developed 6-plex has potential for future on-site testing. Future implementation of this method as a pre-screening tool, prior to

  5. Molecular detection of harmful algal blooms (HABs) using locked nucleic acids and bead array technology.

    Science.gov (United States)

    Diaz, Mara R; Jacobson, James W; Goodwin, Kelly D; Dunbar, Sherry A; Fell, Jack W

    2010-06-01

    Harmful algal blooms (HABs) are a serious public health risk in coastal waters. As the intensity and frequency of HABs continue to rise, new methods of detection are needed for reliable identification. Herein, we developed a high-throughput, multiplex, bead array technique for the detection of the dinoflagellates Karenia brevis and Karenia mikimotoi. The method combined the Luminex detection system with two novel technologies: locked nucleic acid-modified oligonucleotides (LNA) and Mirus Label IT(®) nucleic acid technology. To study the feasibility of the method, we evaluated the performance of modified and unmodified LNA probes with amplicon targets that were biotin labeled with two different strategies: direct chemical labeling (Mirus Label IT) versus enzymatic end-labeling (single biotinylated primer). The results illustrated that LNA probes hybridized to complementary single-stranded DNA with better affinity and displayed higher fluorescence intensities than unmodified oligonucleotide DNA probes. The latter effect was more pronounced when the assay was carried out at temperatures above 53°C degree. As opposed to the enzymatic 5' terminal labeling technique, the chemical-labeling method enhanced the level of fluorescence by as much as ~83%. The detection limits of the assay, which were established with LNA probes and Mirus Label IT system, ranged from 0.05 to 46 copies of rRNA. This high-throughput method, which represents the first molecular detection strategy to integrate Luminex technology with LNA probes and Mirus Label IT, can be adapted for the detection of other HABs and is well suited for the monitoring of red tides at pre-blooming and blooming conditions.

  6. Gold nano-island arrays on silicon as SERS active substrate for organic molecule detection

    Energy Technology Data Exchange (ETDEWEB)

    Ignat, Teodora, E-mail: teodora.ignat@imt.ro [National Institute for Research and Development in Microtechnologies, Laboratory of Nanobiotechnology, 126A, Erou Iancu Nicolae Street, 077190 (Romania); Husanu, Marius-Adrian, E-mail: adrianhusanu@gmail.com [National Institute of Materials Physics, Atomistilor Str. 105bis, PO Box MG 7, Magurele, Bucharest 077125 (Romania); Munoz, Roberto, E-mail: rmunoz@icmm.csic.es [Inasmet Fdn, Dept. Biomat and Nanotechnol, San Sebastian (Spain); Kusko, Mihaela, E-mail: mihaela.kusko@imt.ro [National Institute for Research and Development in Microtechnologies, Laboratory of Nanobiotechnology, 126A, Erou Iancu Nicolae Street, 077190 (Romania); Danila, Mihai, E-mail: mihai.danila@imt.ro [National Institute for Research and Development in Microtechnologies, Laboratory of Nanobiotechnology, 126A, Erou Iancu Nicolae Street, 077190 (Romania); Teodorescu, Cristian Mihail, E-mail: teodorescu@infim.ro [National Institute of Materials Physics, Atomistilor Str. 105bis, PO Box MG 7, Magurele, Bucharest 077125 (Romania)

    2014-01-01

    Gold islands forming highly controlled arrays have been fabricated by two potential step electrochemical deposition method using nanopatterned Si surface templates. In the present work, the Raman scattering studies realized using 11-mercaptoundecanoic probe molecule showed that such structures exhibit an enhanced Raman signal compared with nanostructured physical deposited thin gold film on flat silicon substrate and can be valued as surface-enhanced Raman scattering substrates. Besides the more appropriate management of nano-island arrays distribution, the high ratio of their Raman signals can be explain by the epitaxial-like growth mechanism of the metallic nano-islands, clearly showed by X-ray diffraction studies. Furthermore, the substrates enabled reproducibility and stability detection due to the chemically assembling of organothiol molecules, the X-ray photoelectron spectroscopy studies confirming formation of the thiolate species which corresponds to Au-S bonds, and also, the unwanted ‘hot-spots’ are missing, which make them suitable for high sensitivity biosensing applications. - Highlights: • Gold nano-islands are electrochemical deposited on nanopatterned silicon. • The X-ray diffraction studies revealed the epitaxial-like growth mechanism. • Enhanced Raman signal of Au nano-islands was observed compared with Au nano-film.

  7. A compact array calibrator to study the feasibility of acoustic neutrino detection

    Directory of Open Access Journals (Sweden)

    Ardid M.

    2016-01-01

    Full Text Available Underwater acoustic detection of ultra-high-energy neutrinos was proposed already in 1950s: when a neutrino interacts with a nucleus in water, the resulting particle cascade produces a pressure pulse that has a bipolar temporal structure and propagates within a flat disk-like volume. A telescope that consists of thousands of acoustic sensors deployed in the deep sea can monitor hundreds of cubic kilometres of water looking for these signals and discriminating them from acoustic noise. To study the feasibility of the technique it is critical to have a calibrator able to mimic the neutrino “signature” that can be operated from a vessel. Due to the axial-symmetry of the signal, their very directive short bipolar shape and the constraints of operating at sea, the development of such a calibrator is very challenging. Once the possibility of using the acoustic parametric technique for this aim was validated with the first compact array calibrator prototype, in this paper we describe the new design for such a calibrator composed of an array of piezo ceramic tube transducers emitting in axial direction.

  8. TARA: Forward-scattered radar detection of UHECR at the telescope array

    Directory of Open Access Journals (Sweden)

    Takai H.

    2013-06-01

    Full Text Available Increased event statistics will be required to definitively answer the question of the origin(s of Ultra-High Energy Cosmic Rays (UHECR. Using current technologies however, achieving the necessary statistics may be financially and practically impossible. We describe the status and plans of the TARA project, an effort to detect Ultra-High-Energy Cosmic Rays by their forward scattered or “bistatic” radar signature. Bistatic radar holds promise as a new remote sensing technique for UHECR, without the duty cycle limitations of nitrogen fluorescence detectors. Such a technique could prove key in advancing the study of UHECR beyond the constraints of the current generation of cosmic ray observatories. TARA consists of a low-VHF television transmitter illuminating the air above the Telescope Array (TA, and a set of radio receivers on the far side of TA approximately 50 km distant from the transmitter. We have collected radar data since April 2011 using a 2 kW transmitter at 54.1 MHz. Recently, we received permission to increase our broadcast power to 40 kW and our effective radiated power (ERP to 6 MW. On the receiver end, we are employing software-defined radio receivers and developing real-time trigger algorithms based on the expected air shower radar echo. In addition to presenting an overview of the project status and future plans, we will present the most recent results of searches for coincidences between radar echoes and Telescope Array air shower events.

  9. TARA: Forward-scattered radar detection of UHECR at the telescope array

    Science.gov (United States)

    Belz, J.; Abu Bakr Othman, M.; Allen, C.; Barcikowski, E.; Besson, D.; Farhang-Boroujeny, B.; Ikeda, D.; Hanlon, W.; Kunwar, S.; Lundquist, J. P.; Kravchenko, I.; Larson, S.; Myers, I.; Nakamura, T.; Rankin, J. S.; Sagawa, H.; Sokolsky, P.; Takai, H.; Terasawa, T.; Thomson, G. B.

    2013-06-01

    Increased event statistics will be required to definitively answer the question of the origin(s) of Ultra-High Energy Cosmic Rays (UHECR). Using current technologies however, achieving the necessary statistics may be financially and practically impossible. We describe the status and plans of the TARA project, an effort to detect Ultra-High-Energy Cosmic Rays by their forward scattered or "bistatic" radar signature. Bistatic radar holds promise as a new remote sensing technique for UHECR, without the duty cycle limitations of nitrogen fluorescence detectors. Such a technique could prove key in advancing the study of UHECR beyond the constraints of the current generation of cosmic ray observatories. TARA consists of a low-VHF television transmitter illuminating the air above the Telescope Array (TA), and a set of radio receivers on the far side of TA approximately 50 km distant from the transmitter. We have collected radar data since April 2011 using a 2 kW transmitter at 54.1 MHz. Recently, we received permission to increase our broadcast power to 40 kW and our effective radiated power (ERP) to 6 MW. On the receiver end, we are employing software-defined radio receivers and developing real-time trigger algorithms based on the expected air shower radar echo. In addition to presenting an overview of the project status and future plans, we will present the most recent results of searches for coincidences between radar echoes and Telescope Array air shower events.

  10. A compact array calibrator to study the feasibility of acoustic neutrino detection

    Science.gov (United States)

    Ardid, M.; Camarena, F.; Felis, I.; Herrero, A.; Llorens, C. D.; Martínez-Mora, J.; Saldaña, M.

    2016-04-01

    Underwater acoustic detection of ultra-high-energy neutrinos was proposed already in 1950s: when a neutrino interacts with a nucleus in water, the resulting particle cascade produces a pressure pulse that has a bipolar temporal structure and propagates within a flat disk-like volume. A telescope that consists of thousands of acoustic sensors deployed in the deep sea can monitor hundreds of cubic kilometres of water looking for these signals and discriminating them from acoustic noise. To study the feasibility of the technique it is critical to have a calibrator able to mimic the neutrino "signature" that can be operated from a vessel. Due to the axial-symmetry of the signal, their very directive short bipolar shape and the constraints of operating at sea, the development of such a calibrator is very challenging. Once the possibility of using the acoustic parametric technique for this aim was validated with the first compact array calibrator prototype, in this paper we describe the new design for such a calibrator composed of an array of piezo ceramic tube transducers emitting in axial direction.

  11. 4H-SiC Schottky diode arrays for X-ray detection

    Science.gov (United States)

    Lioliou, G.; Chan, H. K.; Gohil, T.; Vassilevski, K. V.; Wright, N. G.; Horsfall, A. B.; Barnett, A. M.

    2016-12-01

    Five SiC Schottky photodiodes for X-ray detection have been electrically characterized at room temperature. One representative diode was also electrically characterized over the temperature range 20°C to 140 °C. The performance at 30 °C of all five X-ray detectors, in both current mode and for photon counting X-ray spectroscopy was investigated. The diodes were fabricated in an array form such that they could be operated as either a 2×2 or 1×3 pixel array. Although the devices showed double barrier heights, high ideality factors and higher than expected leakage current at room temperature (12 nA/cm2 at an internal electric field of 105 kV/cm), they operated as spectroscopic photon counting soft X-ray detectors uncooled at 30 °C. The measured energy resolution (FWHM at 17.4 keV, Mo Kα) varied from 1.36 to 1.68 keV among different diodes.

  12. Detecting Outlier Microarray Arrays by Correlation and Percentage of Outliers Spots

    Directory of Open Access Journals (Sweden)

    Song Yang

    2006-01-01

    Full Text Available We developed a quality assurance (QA tool, namely microarray outlier filter (MOF, and have applied it to our microarray datasets for the identification of problematic arrays. Our approach is based on the comparison of the arrays using the correlation coefficient and the number of outlier spots generated on each array to reveal outlier arrays. For a human universal reference (HUR dataset, which is used as a technical control in our standard hybridization procedure, 3 outlier arrays were identified out of 35 experiments. For a human blood dataset, 12 outlier arrays were identified from 185 experiments. In general, arrays from human blood samples displayed greater variation in their gene expression profiles than arrays from HUR samples. As a result, MOF identified two distinct patterns in the occurrence of outlier arrays. These results demonstrate that this methodology is a valuable QA practice to identify questionable microarray data prior to downstream analysis.

  13. Ink-Jet Printing: Perfect Tool for Cantilever Array Sensor Preparation for Microbial Growth Detection

    Directory of Open Access Journals (Sweden)

    G. Lukacs

    2012-01-01

    Full Text Available The use of microcantilever arrays for microbial growth detection provides a rapid and reliable technique for monitoring growth in industrial and clinical applications. Improving the reproducibility and sensitivity of this technique is of great importance. Ink-jet printing has been successfully used in microfabrication and biofabrication due to its high precision; however, only a few microbe-based applications have been reported. Here we demonstrate the advantages of its use for microcantilever based-growth sensing. Four microbial strains Escherichia coli, Staphylococcus aureus subsp. aureus, Pseudomonas aeruginosa, and Candida albicans were deposited and successfully grown on agarose-coated cantilevers by ink-jet printing. When compared to the capillary-coating method, ink-jet printing demonstrated more controlled cell deposition on cantilevers. The effect of various conditions on cell morphology was also investigated.

  14. The Feasibility of Using Black Widow Pulsars in Pulsar Timing Arrays for Gravitational Wave Detection

    CERN Document Server

    Bochenek, Christopher; Demorest, Paul

    2015-01-01

    In the past five years, approximately one third of the 65 pulsars discovered by radio observations of Fermi unassociated sources are black widow pulsars (BWPs). BWPs are binary millisecond pulsars with companion masses ranging from 0.01-0.1 solar masses which often exhibit radio eclipses. The bloated companions in BWP systems exert small torques on the system causing the orbit to change on small but measurable time scales. Because adding parameters to a timing model reduces sensitivity to a gravitational wave (GW) signal, the need to fit many orbital frequency derivatives to the timing data is potentially problematic for using BWPs to detect GWs with pulsar timing arrays. Using simulated data with up to four orbital frequency derivatives, we show that fitting for orbital frequency derivatives absorbs less than 5% of the low frequency spectrum expected from a stochastic gravitational wave background signal. Furthermore, this result does not change with orbital period. Therefore, we suggest that if timing syste...

  15. Determination of acaricides in honey by high-performance liquid chromatography with photodiode array detection.

    Science.gov (United States)

    Martel, Anne-Claire; Zeggane, Sarah

    2002-04-19

    Rapid analytical methods are described to control quality of honeys, concerning residues of acaricides applied in hives to prevent Varroa jacobsoni infestation. A liquid-liquid extraction with hexane-propanol-2-ammonia (60 ml:30 ml:0.28%) was used for the simultaneous analysis of coumaphos, bromopropylate, amitraz and fluvalinate. For thymol, one clean up on a solid-phase extraction C18 (500 mg, 6 ml) column was performed; for rotenone, a liquid extraction with dichloromethane was realised. Quantitative recoveries obtained with honey were satisfactory and were superior to 80%. All acaricides are identified by reversed-phase high-performance liquid chromatography with photodiode array detection. Quantification limits obtained were below maximal residue limits when these exist.

  16. Profiling and quantitation of bacterial carotenoids by liquid chromatography and photodiode array detection.

    Science.gov (United States)

    Nelis, H J; De Leenheer, A P

    1989-12-01

    An analytical method for the profiling and quantitative determination of carotenoids in bacteria is described. Exhaustive extraction of the pigments from four selected bacterial strains required treatment of the cells with potassium hydroxide or liquefied phenol or both before the addition of the extracting solvent (methanol or diethyl ether). The carotenoids in the extracts were separated by nonaqueous reversed-phase liquid chromatography in conjunction with photodiode array absorption detection. The identity of a peak was considered definitive only when both its retention time and absorption spectrum, before and after chemical reactions, matched those of a reference component. In the absence of the latter, most peaks could be tentatively identified. Two examples illustrate how in the analysis of pigmented bacteria errors may result from using nonchromatographic procedures or liquid chromatographic methods lacking sufficient criteria for peak identification. Carotenoids of interest were determined quantitatively when the authentic reference substance was available or, alternatively, were determined semiquantitatively.

  17. INTERPLANETARY SCINTILLATION RADIO SOURCES DETECTED WITH THE MEXICAN ARRAY RADIO TELESCOPE (MEXART)

    Science.gov (United States)

    Mejia Ambriz, J. C.; Villanueva-Hernandez, P.; Gonzalez-Esparza, A.; Aguilar-Rodriguez, E.; Andrade-Mascote, E.; Carrillo-Vargas, A.

    2009-12-01

    The Mexican Array Radio Telescope (MEXART) has an antenna composed by 4096 full-wavelength dipoles, covering about 9800 square meters. The instrument is primary devoted to carry out observations of compact stelar radio sources presenting Interplanetary Scintillation (IPS) at 140 MHz. The IPS technique is a very useful tool to perform observations of large-scale solar wind density disturbances in the inner heliosphere at heliocentric ranges where no other instruments can cover. These observations can help to track the evolution of CMEs and shocks in the interplanetary medium. We present the first catalog of IPS sources detected with the MEXART. We show the power spectrum analysis to obtain information of solar wind velocity and density.

  18. Self-referenced silicon nitride array microring biosensor for toxin detection using glycans at visible wavelength

    Science.gov (United States)

    Ghasemi, Farshid; Eftekhar, Ali A.; Gottfried, David S.; Song, Xuezheng; Cummings, Richard D.; Adibi, Ali

    2013-02-01

    We report on application of on-chip referencing to improve the limit-of-detection (LOD) in compact silicon nitride (SiN) microring arrays. Microring resonators, fabricated by e-beam lithography and fluorine-based etching, are designed for visible wavelengths (656nm) and have a footprint of 20 x 20 μm. GM1 ganglioside is used as the specific ligand for recognition of Cholera Toxin Subunit B (CTB), with Ricinus Communis Agglutinin I (RCA I) as a negative control. Using micro-cantilever based printing less than 10 pL of glycan solution is consumed per microring. Real-time data on analyte binding is extracted from the shifts in resonance wavelengths of the microrings.

  19. A Single-Array-Based Method for Detecting Copy Number Variants Using Affymetrix High Density SNP Arrays and its Application to Breast Cancer.

    Science.gov (United States)

    Li, Ming; Wen, Yalu; Fu, Wenjiang

    2014-01-01

    Cumulative evidence has shown that structural variations, due to insertions, deletions, and inversions of DNA, may contribute considerably to the development of complex human diseases, such as breast cancer. High-throughput genotyping technologies, such as Affymetrix high density single-nucleotide polymorphism (SNP) arrays, have produced large amounts of genetic data for genome-wide SNP genotype calling and copy number estimation. Meanwhile, there is a great need for accurate and efficient statistical methods to detect copy number variants. In this article, we introduce a hidden-Markov-model (HMM)-based method, referred to as the PICR-CNV, for copy number inference. The proposed method first estimates copy number abundance for each single SNP on a single array based on the raw fluorescence values, and then standardizes the estimated copy number abundance to achieve equal footing among multiple arrays. This method requires no between-array normalization, and thus, maintains data integrity and independence of samples among individual subjects. In addition to our efforts to apply new statistical technology to raw fluorescence values, the HMM has been applied to the standardized copy number abundance in order to reduce experimental noise. Through simulations, we show our refined method is able to infer copy number variants accurately. Application of the proposed method to a breast cancer dataset helps to identify genomic regions significantly associated with the disease.

  20. Detection of HIV cDNA Point Mutations with Rolling-Circle Amplification Arrays

    Directory of Open Access Journals (Sweden)

    Zhongwei Wu

    2010-01-01

    Full Text Available In this paper we describe an isothermal rolling-circle amplification (RCA protocol to detect gene point mutations on chips. The method is based on an allele-specific oligonucleotide circularization mediated by a special DNA ligase. The probe is circularized when perfect complementary sequences between the probe oligonucleotide and HIV cDNA gene. Mismatches around the ligation site can prevent probe circularization. The circularized probe (C-probe can be amplified by rolling circle amplification to generate multimeric singlestranded DNA (ssDNA under isothermal conditions. There are four sequence regions to bind respectively with fluorescent probe, RCA primer, solid probe and HIV cDNA template in the C-probe which we designed. These ssDNA products are hybridized with fluorescent probes and solid probes which are immobilized on a glass slide composing a regular microarray pattern. The fluorescence signals can be monitored by a scanner in the presence of HIV cDNA templates, whereas the probes cannot be circularized and signal of fluorescence cannot be found. The RCA array has capability of high-throughput detection of the point mutation and the single-nucleotide polymorphism (SNP.The development of C-probe-based technologies offers a promising prospect for situ detection, microarray, molecular diagnosis, single nucleotide polymorphism, and whole genome amplification.

  1. Rapid Detection of Viable Microorganisms Based on a Plate Count Technique Using Arrayed Microelectrodes

    Directory of Open Access Journals (Sweden)

    Behraad Bahreyni

    2013-06-01

    Full Text Available Development of a miniaturized biosensor system that can be used for rapid detection and counting of microorganisms in food or water samples is described. The developed microsystem employs a highly sensitive impedimetric array of biosensors to monitor the growth of bacterial colonies that are dispersed across an agar growth medium. To use the system, a sample containing the bacteria is cultured above the agar layer. Using a multiplexing network, the electrical properties of the medium at different locations are continuously measured, recorded, and compared against a baseline signal. Variations of signals from different biosensors are used to reveal the presence of bacteria in the sample, as well as the locations of bacterial colonies across the biochip. This technique forms the basis for a label-free bacterial detection for rapid analysis of food samples, reducing the detection time by at least a factor of four compared to the current required incubation times of 24 to 72 hours for plate count techniques. The developed microsystem has the potential for miniaturization to a stage where it could be deployed for rapid analysis of food samples at commercial scale at laboratories, food processing facilities, and retailers.

  2. Disordered array of Au covered Silicon nanowires for SERS biosensing combined with electrochemical detection

    Science.gov (United States)

    Convertino, Annalisa; Mussi, Valentina; Maiolo, Luca

    2016-04-01

    We report on highly disordered array of Au coated silicon nanowires (Au/SiNWs) as surface enhanced Raman scattering (SERS) probe combined with electrochemical detection for biosensing applications. SiNWs, few microns long, were grown by plasma enhanced chemical vapor deposition on common microscope slides and covered by Au evaporated film, 150 nm thick. The capability of the resulting composite structure to act as SERS biosensor was studied via the biotin-avidin interaction: the Raman signal obtained from this structure allowed to follow each surface modification step as well as to detect efficiently avidin molecules over a broad range of concentrations from micromolar down to the nanomolar values. The metallic coverage wrapping SiNWs was exploited also to obtain a dual detection of the same bioanalyte by electrochemical impedance spectroscopy (EIS). Indeed, the SERS signal and impedance modifications induced by the biomolecule perturbations on the metalized surface of the NWs were monitored on the very same three-electrode device with the Au/SiNWs acting as both working electrode and SERS probe.

  3. Tunable and label-free virus enrichment for ultrasensitive virus detection using carbon nanotube arrays

    Science.gov (United States)

    Yeh, Yin-Ting; Tang, Yi; Sebastian, Aswathy; Dasgupta, Archi; Perea-Lopez, Nestor; Albert, Istvan; Lu, Huaguang; Terrones, Mauricio; Zheng, Si-Yang

    2016-01-01

    Viral infectious diseases can erupt unpredictably, spread rapidly, and ravage mass populations. Although established methods, such as polymerase chain reaction, virus isolation, and next-generation sequencing have been used to detect viruses, field samples with low virus count pose major challenges in virus surveillance and discovery. We report a unique carbon nanotube size-tunable enrichment microdevice (CNT-STEM) that efficiently enriches and concentrates viruses collected from field samples. The channel sidewall in the microdevice was made by growing arrays of vertically aligned nitrogen-doped multiwalled CNTs, where the intertubular distance between CNTs could be engineered in the range of 17 to 325 nm to accurately match the size of different viruses. The CNT-STEM significantly improves detection limits and virus isolation rates by at least 100 times. Using this device, we successfully identified an emerging avian influenza virus strain [A/duck/PA/02099/2012(H11N9)] and a novel virus strain (IBDV/turkey/PA/00924/14). Our unique method demonstrates the early detection of emerging viruses and the discovery of new viruses directly from field samples, thus creating a universal platform for effectively remediating viral infectious diseases. PMID:27730213

  4. Trace gas detection and monitoring with the Digital Array Gas-correlation Radiometer (DAGR)

    Science.gov (United States)

    Gordley, Larry L.; Hervig, Mark E.; Fish, Chad; McHugh, Martin J.

    2011-05-01

    We present the first results from a Digital Array Gas-correlation Radiometer (DAGR) prototype sensor, and discuss applications in remote sensing of trace gases. The sensor concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR), but overcomes the limitations in solar backscatter applications. The DAGR sensor design can be scaled to the size of a digital camera and is ideal for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Ground-based portable DAGR sensors can monitor carbon sequestration sites or industrial facilities. Aircraft or UAV deployment can quickly survey large areas and are particularly well suited for gas leak detection or carbon monitoring. From space-based platforms, Doppler modulation can be exploited to produce an extremely fine spectral resolution with effective resolving power exceeding 100,000. Such space-based DAGR observations could provide near-global sensing of climatically important species such as such as CO2, CO, CH4, O3 and N2O. Planetary science applications include detection and mapping of biomarkers in the Martian atmosphere.

  5. Detection of HIV cDNA point mutations with rolling-circle amplification arrays.

    Science.gov (United States)

    Wu, Lingwei; Liu, Quanjun; Wu, Zhongwei; Lu, Zuhong

    2010-01-27

    In this paper we describe an isothermal rolling-circle amplification (RCA) protocol to detect gene point mutations on chips. The method is based on an allele-specific oligonucleotide circularization mediated by a special DNA ligase. The probe is circularized when perfect complementary sequences between the probe oligonucleotide and HIV cDNA gene. Mismatches around the ligation site can prevent probe circularization. The circularized probe (C-probe) can be amplified by rolling circle amplification to generate multimeric singlestranded DNA (ssDNA) under isothermal conditions. There are four sequence regions to bind respectively with fluorescent probe, RCA primer, solid probe and HIV cDNA template in the C-probe which we designed. These ssDNA products are hybridized with fluorescent probes and solid probes which are immobilized on a glass slide composing a regular microarray pattern. The fluorescence signals can be monitored by a scanner in the presence of HIV cDNA templates, whereas the probes cannot be circularized and signal of fluorescence cannot be found. The RCA array has capability of high-throughput detection of the point mutation and the single-nucleotide polymorphism (SNP).The development of C-probe-based technologies offers a promising prospect for situ detection, microarray, molecular diagnosis, single nucleotide polymorphism, and whole genome amplification.

  6. Heteroduplex analysis by capillary array electrophoresis for rapid mutation detection in large multiexon genes.

    Science.gov (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Pérez-Cabornero, Lucía; Sanz, David J; Esteban-Cardeñosa, Eva; Miner, Cristina

    2007-01-01

    Heteroduplex analysis (HA) has proven to be a robust tool for mutation detection. HA by capillary array electrophoresis (HA-CAE) was developed to increase throughput and allow the scanning of large multiexon genes in multicapillary DNA sequencers. HA-CAE is a straightforward and high-throughput technique to detect both known and novel DNA variants with a high level of sensitivity and specificity. It consists of only three steps: multiplex-PCR using fluorescently labeled primers, heteroduplex formation and electrophoresis in a multicapillary DNA sequencer. It allows, e.g., the complete coding and flanking intronic sequences of BRCA1 and BRCA2 genes from two patients (approximately 25 kb each) to be scanned in a single run of a 16-capillary sequencer, and has enabled us to detect 150 different mutations to date (both single nucleotide substitutions, or SNSs, and small insertions/deletions). Here, we describe the protocol developed in our laboratory to scan BRCA1, BRCA2, MLH1, MSH2 and MSH6 genes using an ABI3130XL sequencer. This protocol could be adapted to other instruments or to the study of other large multiexon genes and can be completed in 7-8 h.

  7. Multiplexed cancer biomarker detection using chip-integrated silicon photonic sensor arrays.

    Science.gov (United States)

    Washburn, Adam L; Shia, Winnie W; Lenkeit, Kimberly A; Lee, So-Hyun; Bailey, Ryan C

    2016-09-21

    The analysis of disease-specific biomarker panels holds promise for the early detection of a range of diseases, including cancer. Blood-based biomarkers, in particular, are attractive targets for minimally-invasive disease diagnosis. Specifically, a panel of organ-specific biomarkers could find utility as a general disease surveillance tool enabling earlier detection or prognostic monitoring. Using arrays of chip-integrated silicon photonic sensors, we describe the simultaneous detection of eight cancer biomarkers in serum in a relatively rapid (1 hour) and fully automated antibody-based sandwich assay. Biomarkers were chosen for their applicability to a range of organ-specific cancers, including disease of the pancreas, liver, ovary, breast, lung, colorectum, and prostate. Importantly, we demonstrate that selected patient samples reveal biomarker "fingerprints" that may be useful for a personalized cancer diagnosis. More generally, we show that the silicon photonic technology is capable of measuring multiplexed panels of protein biomarkers that may have broad utility in clinical diagnostics.

  8. Detection and localization of continuous gravitational waves with pulsar timing arrays: the role of pulsar terms

    CERN Document Server

    Zhu, Xingjiang; Xiong, Jie; Xu, Yanjun; Wang, Yan; Mohanty, Soumya D; Hobbs, George; Manchester, Richard N

    2016-01-01

    A pulsar timing array is a Galactic-scale detector of nanohertz gravitational waves (GWs). Its target signals contain two components: the `Earth term' and the `pulsar term' corresponding to GWs incident on the Earth and pulsar respectively. In this work we present a Frequentist method for the detection and localization of continuous waves that takes into account the pulsar term and is significantly faster than existing methods. We investigate the role of pulsar terms by comparing a full-signal search with an Earth-term-only search for non-evolving black hole binaries. By applying the method to synthetic data sets, we find that (i) a full-signal search can slightly improve the detection probability (by about five percent); (ii) sky localization is biased if only Earth terms are searched for and the inclusion of pulsar terms is critical to remove such a bias; (iii) in the case of strong detections (with signal-to-noise ratio $\\gtrsim$ 30), it may be possible to improve pulsar distance estimation through GW meas...

  9. Multiband array detection and location of seismic sources recorded by dense seismic networks

    Science.gov (United States)

    Poiata, Natalia; Satriano, Claudio; Vilotte, Jean-Pierre; Bernard, Pascal; Obara, Kazushige

    2016-06-01

    We present a new methodology for detection and space-time location of seismic sources based on multiscale, frequency-selective coherence of the wave field recorded by dense large-scale seismic networks and local antennas. The method is designed to enhance coherence of the signal statistical features across the array of sensors and consists of three steps: signal processing, space-time imaging, and detection and location. The first step provides, for each station, a simplified representation of seismic signal by extracting multiscale non-stationary statistical characteristics, through multiband higher-order statistics or envelopes. This signal processing scheme is designed to account for a priori unknown transients, potentially associated with a variety of sources (e.g. earthquakes, tremors), and to prepare data for a better performance in posterior steps. Following space-time imaging is carried through 3-D spatial mapping and summation of station-pair time-delay estimate functions. This step produces time-series of 3-D spatial images representing the likelihood that each pixel makes part of a source. Detection and location is performed in the final step by extracting the local maxima from the 3-D spatial images. We demonstrate the efficiency of the method in detecting and locating seismic sources associated with low signal-to-noise ratio on an example of the aftershock earthquake records from local stations of International Maule Aftershock Deployment in Central Chile. The performance and potential of the method to detect, locate and characterize the energy release associated with possibly mixed seismic radiation from earthquakes and low-frequency tectonic tremors is further tested on continuous data from southwestern Japan.

  10. Possible gamma-ray burst radio detections by the Square Kilometre Array. New perspectives

    Science.gov (United States)

    Ruggeri, Alan Cosimo; Capozziello, Salvatore

    2016-09-01

    The next generation interferometric radio telescope, the Square Kilometre Array (SKA), which will be the most sensitive and largest radio telescope ever constructed, could greatly contribute to the detection, survey and characterization of Gamma Ray Bursts (GRBs). By the SKA, it will be possible to perform the follow up of GRBs even for several months. This approach would be extremely useful to extend the Spectrum Energetic Distribution (SED) from the gamma to the to radio band and would increase the number of radio detectable GRBs. In principle, the SKA could help to understand the physics of GRBs by setting constraints on theoretical models. This goal could be achieved by taking into account multiple observations at different wavelengths in order to obtain a deeper insight of the sources. Here, we present an estimation of GRB radio detections, showing that the GRBs can really be observed by the SKA. The approach that we present consists in determining blind detection rates derived by a very large sample consisting of merging several GRB catalogues observed by current missions as Swift, Fermi, Agile and INTEGRAL and by previous missions as BeppoSAX, CGRO, GRANAT, HETE-2, Ulysses and Wind. The final catalogue counts 7516 distinct sources. We compute the fraction of GRBs that could be observed by the SKA at high and low frequencies, above its observable sky. Considering the planned SKA sensitivity and through an extrapolation based on previous works and observations, we deduce the minimum fluence in the range 15-150 keV. This is the energy interval where a GRB should emit to be detectable in the radio band by the SKA. Results seem consistent with observational capabilities.

  11. Extensive screening system using suspension array technology to detect mitochondrial DNA point mutations.

    Science.gov (United States)

    Nishigaki, Yutaka; Ueno, Hitomi; Coku, Jorida; Koga, Yasutoshi; Fujii, Tatsuya; Sahashi, Ko; Nakano, Kazutoshi; Yoneda, Makoto; Nonaka, Michiko; Tang, Linya; Liou, Chia-Wei; Paquis-Flucklinger, Veronique; Harigaya, Yasuo; Ibi, Tohru; Goto, Yu-ichi; Hosoya, Hiroko; DiMauro, Salvatore; Hirano, Michio; Tanaka, Masashi

    2010-04-01

    We established an extensive and rapid system using suspension array to detect 61 representative mitochondrial DNA (mtDNA) heteroplasmic or homoplasmic point mutations (29 for Series A and 32 for Series B) in 22 genes: 1 each in MT-RNR1, -TV, -ND1, -TQ, -TW, -TC, and -TH genes; 2 each in MT-TN, -TG, -ND4, -TL2, -TE, and -CYB genes; 3 each in MT-ATP6, -ND3, and -ND5 genes; 4 each in MT-CO1 and -TK genes; 5 each in MT-TI, -TS1, and -ND6 genes; and 10 in the MT-TL1 gene. We carefully selected 5'-biotinylated primers and pooled primers for use in two sets of multiplex-PCR amplifications. To detect both mutant and wild-type mtDNA, even when polymorphisms were present near the target mutation sites, we designed specific oligonucleotide probes. By using the mtDNA point mutation detection system of Series A (29 mutations) and Series B (32 mutations), we screened a total of 3103 mutant sites in 107 DNA samples for Series A and 13,101 mutant sites in 397 DNA samples for Series B. We succeeded in determining 99.4% (Series A) and 99.6% (Series B) of the targeted mutant sites by use of the system. The 22 samples with the m.3243A>G heteroplasmic mutation revealed positive signals with both mutant- and wild-type-specific probes in this detection system with a detection limit of approximately 2%. This genetic screening platform is useful to reach a definitive diagnosis for mitochondrial diseases. Copyright 2010 Mitochondria Research Society. Published by Elsevier B.V. All rights reserved.

  12. Development of real-time PCR array for simultaneous detection of eight human blood-borne viral pathogens.

    Directory of Open Access Journals (Sweden)

    Natalia Pripuzova

    Full Text Available BACKGROUND: Real-time PCR array for rapid detection of multiple viral pathogens should be highly useful in cases where the sample volume and the time of testing are limited, i.e. in the eligibility testing of tissue and organ donors. FINDINGS: We developed a real-time PCR array capable of simultaneously detecting eight human viral pathogens: human immunodeficiency virus types 1 and 2 (HIV-1 and -2, hepatitis B virus (HBV, hepatitis C virus (HCV, human T-cell leukemia virus-1 and -2 (HTLV-1 and -2, vaccinia virus (VACV and West Nile virus (WNV. One hundred twenty (120 primers were designed using a combination of bioinformatics approaches, and, after experimental testing, 24 primer sets targeting eight viral pathogens were selected to set up the array with SYBR Green chemistry. The specificity and sensitivity of the virus-specific primer sets selected for the array were evaluated using analytical panels with known amounts of viruses spiked into human plasma. The array detected: 10 genome equivalents (geq/ml of HIV-2 and HCV, 50 geq of HIV-1 (subtype B, HBV (genotype A and WNV. It detected 100-1,000 geq/ml of plasma of HIV-1 subtypes (A - G, group N and CRF (AE and AG isolates. Further evaluation with a panel consisting of 28 HIV-1 and HIV-2 clinical isolates revealed no cross-reactivity of HIV-1 or HIV-2 specific primers with another type of HIV. All 28 viral isolates were identified with specific primer sets targeting the most conserved genome areas. The PCR array correctly identified viral infections in a panel of 17 previously quantified clinical plasma samples positive for HIV-1, HCV or HBV at as low as several geq per PCR reaction. CONCLUSIONS: The viral array described here demonstrated adequate performance in the testing of donors' clinical samples. Further improvement in its sensitivity for the broad spectrum of HIV-1 subtypes is under development.

  13. HNA and ANA high-affinity arrays for detections of DNA and RNA single-base mismatches.

    Science.gov (United States)

    Abramov, Mikhail; Schepers, Guy; Van Aerschot, Arthur; Van Hummelen, Paul; Herdewijn, Piet

    2008-06-15

    DNA microarrays and sensors have become essential tools in the functional analysis of sequence information. Recently we reported that chimeric hexitol (HNA) and altritol (ANA) nucleotide monomers with an anhydrohexitol sugar moiety are easily available and proved their chemistry to be compatible with DNA and RNA synthesis. In this communication we describe a novel analytical platform based on HNA and ANA units to be used as synthetic oligonucleotide arrays on a glass solid support for match/mismatch detection of DNA and RNA targets. Arrays were fabricated by immobilization of diene-modified oligonucleotides on maleimido-activated glass slides. To demonstrate the selectivity and sensitivity of the HNA/ANA arrays and to compare their properties with regular DNA arrays, sequences in the reverse transcriptase gene (codon 74) and the protease gene of HIV-1 (codon 10) were selected. Both, the relative intensity of the signal and match/mismatch discrimination increased up to fivefold for DNA targets and up to 3-3.5-fold for RNA targets applying HNA or ANA arrays (ANA>HNA>DNA). Certainly in the new field of miRNA detection, ANA arrays could prove very beneficial and their properties should be investigated in more detail.

  14. High taxonomic level fingerprint of the human intestinal microbiota by ligase detection reaction--universal array approach.

    Science.gov (United States)

    Candela, Marco; Consolandi, Clarissa; Severgnini, Marco; Biagi, Elena; Castiglioni, Bianca; Vitali, Beatrice; De Bellis, Gianluca; Brigidi, Patrizia

    2010-04-19

    Affecting the core functional microbiome, peculiar high level taxonomic unbalances of the human intestinal microbiota have been recently associated with specific diseases, such as obesity, inflammatory bowel diseases, and intestinal inflammation. In order to specifically monitor microbiota unbalances that impact human physiology, here we develop and validate an original DNA-microarray (HTF-Microbi.Array) for the high taxonomic level fingerprint of the human intestinal microbiota. Based on the Ligase Detection Reaction-Universal Array (LDR-UA) approach, the HTF-Microbi.Array enables specific detection and approximate relative quantification of 16S rRNAs from 30 phylogenetically related groups of the human intestinal microbiota. The HTF-Microbi.Array was used in a pilot study of the faecal microbiota of eight young adults. Cluster analysis revealed the good reproducibility of the high level taxonomic microbiota fingerprint obtained for each of the subject. The HTF-Microbi.Array is a fast and sensitive tool for the high taxonomic level fingerprint of the human intestinal microbiota in terms of presence/absence of the principal groups. Moreover, analysis of the relative fluorescence intensity for each probe pair of our LDR-UA platform can provide estimation of the relative abundance of the microbial target groups within each samples. Focusing the phylogenetic resolution at division, order and cluster levels, the HTF-Microbi.Array is blind with respect to the inter-individual variability at the species level.

  15. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    Science.gov (United States)

    Xie, Qing; Cheng, Shuyi; Lü, Fangcheng; Li, Yanqing

    2014-03-01

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application.

  16. Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.

    1989-05-01

    Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs.

  17. THE MINIMUM WIDTH OF THE ARRIVAL DIRECTION DISTRIBUTION OF ULTRA-HIGH-ENERGY COSMIC RAYS DETECTED WITH THE YAKUTSK ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A. A., E-mail: ivanov@ikfia.ysn.ru [Shafer Institute for Cosmophysical Research and Aeronomy, 31 Lenin Avenue, Yakutsk 677980 (Russian Federation)

    2015-05-10

    This paper presents the results of searches for anisotropy in the arrival directions of ultra-high-energy cosmic rays (CRs) detected with the Yakutsk Array during the 1974–2008 observational period as well as searches in available data from other giant extensive air shower arrays working at present. A method of analysis based on a comparison of the minimum width of distributions in equatorial coordinates is used. As a result, a hypothesis of isotropy in arrival directions is rejected at the 99.5% significance level. The observed decrease in the minimum width of the distribution can be explained by the presence of CR sources in energy intervals and sky regions according to recent indications inferred from data of the Yakutsk Array and Telescope Array experiments.

  18. A minimal width of the arrival direction distribution of ultra-high energy cosmic rays detected with the Yakutsk array

    CERN Document Server

    Ivanov, A A

    2015-01-01

    This paper presents the results of searches for anisotropy in arrival directions of ultra-high energy cosmic rays detected with the Yakutsk Array during the 1974--2008 observational period together with available data from other giant extensive air shower arrays working at present. A method of analysis based on a comparison of the minimal width of distributions in equatorial coordinates is applied. As a result, a hypothesis of isotropy in arrival directions is rejected at the $99.5\\%$ significance level. The observed decrease in the minimal width of distribution can be explained by the presence of cosmic ray sources in energy intervals and sky regions according to the recent indications inferred from data of the Yakutsk Array and Telescope Array experiments.

  19. The potential of TaqMan Array Cards for detection of multiple biological agents by real-time PCR.

    Directory of Open Access Journals (Sweden)

    Phillip A Rachwal

    Full Text Available The TaqMan Array Card architecture, normally used for gene expression studies, was evaluated for its potential to detect multiple bacterial agents by real-time PCR. Ten PCR assays targeting five biological agents (Bacillus anthracis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, and Yersinia pestis were incorporated onto Array Cards. A comparison of PCR performance of each PCR in Array Card and singleplex format was conducted using DNA extracted from pure bacterial cultures. When 100 fg of agent DNA was added to Array Card channels the following levels of agent detection (where at least one agent PCR replicate returned a positive result were observed: Y. pestis 100%, B. mallei & F. tularensis 93%; B. anthracis 71%; B. pseudomallei 43%. For B. mallei & pseudomallei detection the BPM2 PCR, which detects both species, outperformed PCR assays specific to each organism indicating identification of the respective species would not be reproducible at the 100 fg level. Near 100% levels of detection were observed when 100 fg of DNA was added to each PCR in singleplex format with singleplex PCRs also returning sporadic positives at the 10 fg per PCR level. Before evaluating the use of Array Cards for the testing of environmental and clinical sample types, with potential levels of background DNA and PCR inhibitors, users would therefore have to accept a 10-fold reduction in sensitivity of PCR assays on the Array Card format, in order to benefit for the capacity to test multiple samples for multiple agents. A two PCR per agent strategy would allow the testing of 7 samples for the presence of 11 biological agents or 3 samples for 23 biological agents per card (with negative control channels.

  20. Detection and localization using an acoustic array on a small robotic platform

    Science.gov (United States)

    Young, Stuart H.; Scanlon, Michael V.

    2003-09-01

    The future battlefield will require an unprecedented level of automation in which soldier-operated autonomous and semi-autonomous ground, air and sea platforms along with mounted and dismounted soldiers will function as a tightly coupled team. Sophisticated robotic platforms with diverse sensor suites will be an integral part of the Objective Force, and must be able to collaborate not only amongst themselves but also with their manned partners. The Army Research Laboratory has developed a robot-based acoustic detection system that will detect and localize on an impulsive noise event, such as a sniper's weapon firing. Additionally, acoustic sensor arrays worn on a soldier's helmet or equipment can enhance his situational awareness and RSTA capabilities. The Land Warrior or Objective Force Warrior body-worn computer can detect tactically significant impulsive signatures from bullets, mortars, artillery, and missiles or spectral signatures from tanks, helicopters, UAVs, and mobile robots. Time-difference-of-arrival techniques can determine a sound's direction of arrival, while head attitude sensors can instantly determine the helmet orientation at time of capture. With precision GPS location of the soldier, along with the locations of other soldiers, robots, or unattended ground sensors that heard the same event, triangulation techniques can produce an accurate location of the target. Data from C-4 explosions and 0.50-Caliber shots shows that both helmet and robot systems can localize on the same event. This provides an awesome capability - mobile robots and soldiers working together on an ever-changing battlespace to detect the enemy and improve the survivability, mobility, and lethality of our future warriors.

  1. Chemically Selective Coated Quartz Crystal Microbalance (QCM) Array for Detection of Volatile Organic Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Bohuszewicz, T.V.; Frye-Mason, G.C.; Martin, S.J.; Osbourn, G.C. Bartholomew, J.W.; Schneider, T.W.; Spates, J.J.

    1998-11-04

    Liquid flow cells have been fabricated to prepare an array of QCMS operating simultaneously for detection and identification of VOCS in water. TWO signals, a tlequency response and a damping voltage response, were obtained per resonator. A blank QCM was used as a reference to account for changes in liquid density and viscosity. Nine different polymer coatings applied using a spin coat technique have been examined for VOC response under liquid flow conditions. A matrix of three classes of VOCS were examined for each coating with four chemicals in each class. The three classes of VOCS are polar, nonpolar and chlorinated. A pattern recognition technique, called visually empirical region of influence (VERI), was used to cluster the responses in n-dimensional space. Chemicals within a class varying by only one methyl group (e.g., toluene and xylene) are easily discriminated using only two different coatings with three different QCM responses. All chemicak were easily separated and detected with a total of 5 films and 6 responses with >99% accuracy.

  2. Guided wave phased array sensor tuning for improved defect detection and characterization

    Science.gov (United States)

    Philtron, Jason H.; Rose, Joseph L.

    2014-03-01

    Ultrasonic guided waves are finding increased use in a variety of Nondestructive Evaluation and Structural Health Monitoring applications due to their efficiency in defect detection using a sensor at a single location to inspect a large area of a structure and an ability to inspect hidden and coated areas for example. With a thorough understanding of guided wave mechanics, researchers can predict which guided wave modes will have a high probability of success in a particular nondestructive evaluation application. For example, in a sample problem presented here to access bond integrity, researchers may choose to use a guided wave mode which has high in-plane displacement, stress, or other feature at the interface. However, since material properties used for modeling work may not be precise for the development of dispersion curves, in many cases guided wave mode and frequency selection should be adjusted for increased inspection efficiency in the field. In this work, a phased array comb transducer is used to sweep over phase velocity - frequency space to tune mode excitation for improved defect characterization performance. A thin polycarbonate layer bonded to a thick metal plate is considered with a contaminated surface prior to bonding. Physicallybased features are used to correlate wave signals with defect detection. Features assessed include arrival time and the frequency of maximum amplitude. A pseudo C-scan plot is presented which can be used to simplify data analysis. Excellent results are obtained.

  3. Disposable electrochemical DNA-array for PCR amplified detection of hazelnut allergens in foodstuffs.

    Science.gov (United States)

    Bettazzi, Francesca; Lucarelli, Fausto; Palchetti, Ilaria; Berti, Francesca; Marrazza, Giovanna; Mascini, Marco

    2008-04-28

    An electrochemical low-density DNA-array has been designed and implemented to be used in combination with polymerase chain reaction (PCR) in order to investigate the presence of hazelnut major allergens (Cor a 1.04, Cor a 1.03) in foodstuff. Unmodified PCR products were captured at the sensor interface via sandwich hybridization with surface-tethered probes and biotinylated signalling probes. The resulting biotinylated hybrids were coupled with a streptavidin-alkaline phosphatase conjugate and then exposed to a alpha-naphthyl phosphate solution. Differential pulse voltammetry was finally used to detect the alpha-naphthol signal. The detection limits for Cor a 1.03 and Cor a 1.04 were 0.3 and 0.1 nmol L(-1), respectively (R.S.D. 10%). The optimized conditions were used to test several commercially available foodstuffs, claiming to contain or not the targeted nuts. The results were compared with those obtained with classical ELISA tests.

  4. Chemically selective coated quartz-crystal-microbalance (QCM) array for detection of volatile organic chemicals

    Science.gov (United States)

    Schneider, Thomas W.; Frye-Mason, Gregory C.; Martin, Stephen J.; Spates, James J.; Bohuszewicz, Teresa V.; Osbourn, Gordon C.; Bartholomew, John W.

    1998-12-01

    Liquid flow cells have been fabricated to prepare an array of QCMs operating simultaneously for detection and identification of VOCs in water. Two signals, a frequency response and a damping voltage response, were obtained per resonator. A blank QCM was used as a reference to account for changes in liquid density and viscosity. Nine different polymer coatings applied using a spin coat technique have been examined for VOC response under liquid flow conditions. A matrix of three classes of VOCs were examined for each coating with four chemicals in each class. The three classes of VOCs are polar, nonpolar and chlorinated. A pattern recognition technique, called visually empirical region of influence, was used to cluster the responses in n- dimensional space. Chemicals within a class varying by only one methyl group (e.g., toluene and xylene) are easily discriminated using only two different coatings with three different QCM responses. All chemicals were easily separated and detected with a total of 5 films and 6 responses with >99% accuracy.

  5. Electrochemical biosensor for Mycobacterium tuberculosis DNA detection based on gold nanotubes array electrode platform.

    Science.gov (United States)

    Torati, Sri Ramulu; Reddy, Venu; Yoon, Seok Soo; Kim, CheolGi

    2016-04-15

    The template assisted electrochemical deposition technique was used for the synthesis of gold nanotubes array (AuNTsA). The morphological structure of the synthesized AuNTsA was observed by scanning electron microscopy and found that the individual nanotubes are around 1.5 μm in length with a diameter of 200 nm. Nanotubes are vertically aligned to the Au thick film, which is formed during the synthesis process of nanotubes. The electrochemical performance of the AuNTsA was compared with the bare Au electrode and found that AuNTsA has better electron transfer surface than bare Au electrode which is due to the high surface area. Hence, the AuNTsA was used as an electrode for the fabrication of DNA hybridization biosensor for detection of Mycobacterium Tuberculosis DNA. The DNA hybridization biosensor constructed by AuNTsA electrode was characterized by cyclic voltammetry technique with Fe(CN)6(3-/4-) as an electrochemical redox indicator. The selectivity of the fabricated biosensor was illustrated by hybridization with complementary DNA and non-complementary DNA with probe DNA immobilized AuNTsA electrode using methylene blue as a hybridization indicator. The developed electrochemical DNA biosensor shows good linear range of complementary DNA concentration from 0.01 ng/μL to 100 ng/μL with high detection limit.

  6. Detecting gravitational waves with pulsar-timing arrays: a case of astrophysical forensics

    Science.gov (United States)

    Vallisneri, Michele

    2016-03-01

    Pulsar-timing arrays have recently reached maturity as the ``third way'' to gravitational-wave (GW) detection, besides ground-based interferometers and future space-based observatories. PTA campaigns target the very-low-frequency band centered around 10- 8 Hz, so they will yield science complementary to the other two programs. For this speaker, much of the fascination with PTAs lies in the fact that they represent a grand experiment in precision measurement that was set up by Nature herself, so we have rather little control on it, and few knobs to turn. Improvements in sensitivity will come as much from ever more powerful radiotelescopes as from a better understanding of the ``detectors'' (neutron stars, their dynamics in binaries, the interstellar medium, ...), and from deeper, more probing analyses of the data we already have. A positive GW detection claim will require making a watertight case of astrophysical forensics, proving beyond any reasonable doubt that systematics are under control, and designing the complex inference chain that points to the presence GWs in its most unequivocal and defensible form. I discuss how these goals and concerns informed the development of recently published constraints on the astrophysical population of supermassive black-hole binaries.

  7. The radio environment of the 21 Centimeter Array: RFI detection and mitigation

    CERN Document Server

    Huang, Yan; Zheng, Qian; Gu, Jun-Hua; Xu, Haiguang

    2016-01-01

    Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detection of the cosmic dawn and epoch of reionization (EoR). In this paper we demonstrate the technique and efficiency of RFI identification and mitigation for the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of EoR. For terrestrial, man-made RFI, we concentrate mainly on a statistical approach by identifying and then excising non-Gaussian signatures, in the sense that the extremely weak cosmic signal is actually buried under thermal and therefore Gaussian noise. We also introduce the so-called visibility correlation coefficient instead of conventional visibility, which allows a further suppression of rapidly time-varying RFI. Finally, we briefly discuss removals of the sky RFI, the leakage of sidelobes from off-field strong radio sources with time-invarian...

  8. Detection of volatile compounds with mass-sensitive sensor arrays in the presence of variable ambient humidity.

    Science.gov (United States)

    Dickert, F L; Hayden, O; Zenkel, M E

    1999-04-01

    Mass-sensitive sensor arrays were established for the detection of isomeric or highly analogue analyte mixtures, which show similar physical and morphological properties. Supramolecular host-guest chemistry and arrays of four mass-sensitive quartz crystal microbalances have been successfully combined with multivariate calibration techniques in the presence of variable air moisture. This system enabled even the separation of xylene isomers [Formula: see text] a task that might be crucial even by gas chromatography. The data of the sensor arrays were analyzed with partial least squares and artificial neural networks. The xylene isomers could be detected with an accuracy of ∼1% in the range of 0-200 ppm, nearly eliminating the residual water cross-sensitivity of the sensor coatings, which allows effective work place or environmental monitoring of toxic compounds with fast response levels.

  9. Impedance biosensor based on interdigitated electrode array for detection of E.coli O157:H7 in food products

    Science.gov (United States)

    Ghosh Dastider, Shibajyoti; Barizuddin, Syed; Dweik, Majed; Almasri, Mahmoud F.

    2012-05-01

    An impedance biosensor was designed, fabricated and tested for detection of viable Escherichia coli O157:H7 in food samples. This device consists of interdigitated microelectrode array (IDEA) fabricated using thin layer of sputtered gold, embedded under a polydimethylsiloxane (PDMS) microchannel. The array of electrodes is designed to detect viable EColi in different food products. The active surface area of the detection array was modified using goat anti-E.coli polyclonal IgG antibody. Contaminated food samples were tested by infusing the supernatant containing bacteria over the IDEA's, through the microchannel. Antibody-antigen binding on the electrodes results in impedance change. Four serial concentrations of E.coli contaminated food samples (3x102 CFUmL-1 to 3x105 CFUmL-1) were tested. The biosensor successfully detected the E.coli samples, with the lower detection limit being 3x103 CFUmL-1 (up to 3cells/μl). Comparing the test results with an IDEA impedance biosensor without microchannel (published elsewhere) indicates that this biosensor have two order of magnitude times higher sensitivity. The proposed biosensor provides qualitative and quantitative detection, and potentially could be used for detection of other type of bacteria by immobilizing the specific type of antibody.

  10. Coulometric generation of reagents using permselective interphases. Pt. 3. Pulse coulometric determination of sulphate in water and oil samples; precipitation titration as PbSO/sub 4/ in mixed solvents

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, E.; Hackmann, B.

    1981-01-01

    A method for precipitation-titrimetric determination of sulphate by coulometrically generated Pb/sup 2 +/ is described. The Pb/sup 2 +/ ions are transported by an equivalent current across a n-PbSe-membrane. Coulometry is performed with a specially developed pulse-coulometer which generates defined pulses with variable delay time. Adsorption effects on differently pretreated Pt-electrodes are used for indication. Precipitation is performed in wateracetone mixtures, acidified by addition of perchloric acid. The method has been tested on rain-water samples, tap-water samples, mineral waters and (after combustion) on oil samples. Comparison with alternative methods proves the more precise and correct results of our new method, combined with better possibilities for automation.

  11. The Distributed Biological Observatory (DBO): A Change Detection Array in the Pacific Arctic Region

    Science.gov (United States)

    Grebmeier, J. M.; Moore, S. E.; Cooper, L. W.; Frey, K. E.; Pickart, R. S.

    2012-12-01

    The Pacific region of the Arctic Ocean is experiencing major reductions in seasonal sea ice extent and increases in sea surface temperatures. One of the key uncertainties in this region is how the marine ecosystem will respond to seasonal shifts in the timing of spring sea ice retreat and/or delays in fall sea ice formation. Climate changes are likely to result in shifts in species composition and abundance, northward range expansions, and changes in lower trophic level productivity that can directly cascade and affect the life cycles of higher trophic level organisms. The developing Distributed Biological Observatory (DBO) is composed of focused biological and oceanographic sampling at biological "hot spot" sites for lower and higher trophic organisms on a latitudinal S-to-N array. The DBO is being developed by an international consortium of scientists in the Pacific Arctic as a change detection array to systematically track the broad biological response to sea ice retreat and associated environmental change. Coordinated ship-based observations over various seasons, together with satellite and mooring data collections at the designated sites, can provide an early detection system for biological and ecosystem response to climate warming. The data documenting the importance of these ecosystem "hotspots" provide a growing marine time-series from the northern Bering Sea to Barrow Canyon at the boundary of the Chukchi and Beaufort seas. Results from these studies show spatial changes in carbon production and export to the sediments as indicated by infaunal community composition and biomass, shifts in sediment grain size on a S-to-N latitudinal gradient, and range extensions for lower trophic levels and further northward migration of higher trophic organisms, such as gray whales. There is also direct evidence of negative impacts on ice dependent species, such as walrus and polar bears. As a ramp up to a fully operational observatory, hydrographic transects and select

  12. Comparison of simulated and experimental 3D laser images using a GmAPD array: application to long range detection

    Science.gov (United States)

    Coyac, Antoine; Riviere, Nicolas; Hespel, Laurent; Briottet, Xavier

    2016-05-01

    In this paper, we show the feasibility and the benefit to use a Geiger-mode Avalanche Photo-Diode (GmAPD) array for long range detection, up to several kilometers. A simulation of a Geiger detection sensor is described, which is a part of our end-to-end laser simulator, to generate simulated 3D laser images from synthetic scenes. Resulting 3D point clouds have been compared to experimental acquisitions, performed with our GmAPD 3D camera on similar scenarios. An operational case of long range detection is presented: a copper cable outstretched above the ground, 1 kilometer away the experimental system and with a horizontal line-of-sight (LOS). The detection of such a small object from long distance observation strongly suggests that GmAPD focal plane arrays could be easily used for real-time 3D mapping or surveillance applications from airborne platforms, with good spatial and temporal resolutions.

  13. Multi-residue analysis of anabolics in calf urine using high-performance liquid chromatography with diode-array detection

    NARCIS (Netherlands)

    Koole, A; Franke, J.P.; de Zeeuw, R.A

    1999-01-01

    We describe the development of an HPLC method with diode-array detection (DAD) for the analysis and identification of 20 substances with anabolic properties, that are considered as potential growth promoters, to be used for the analysis of extracts of calf urine samples. The substances are separated

  14. Detection of Neisseria meningitidis from Negative Blood Cultures and Cerebrospinal Fluid with the FilmArray Blood Culture Identification Panel

    OpenAIRE

    Pardo, Joe; Klinker, Kenneth P.; Borgert, Samuel J.; Butler, Brittany M.; Rand, Kenneth H.; Iovine, Nicole M.

    2014-01-01

    The FilmArray blood culture identification (BCID) panel is a rapid molecular diagnostic test approved for use with positive blood culture material. We describe a fatal case of meningococcemia with central nervous system (CNS) involvement detected using the BCID test with culture-negative blood and cerebrospinal fluid.

  15. Detection of Neisseria meningitidis from negative blood cultures and cerebrospinal fluid with the FilmArray blood culture identification panel.

    Science.gov (United States)

    Pardo, Joe; Klinker, Kenneth P; Borgert, Samuel J; Butler, Brittany M; Rand, Kenneth H; Iovine, Nicole M

    2014-06-01

    The FilmArray blood culture identification (BCID) panel is a rapid molecular diagnostic test approved for use with positive blood culture material. We describe a fatal case of meningococcemia with central nervous system (CNS) involvement detected using the BCID test with culture-negative blood and cerebrospinal fluid.

  16. Multi-residue analysis of anabolics in calf urine using high-performance liquid chromatography with diode-array detection

    NARCIS (Netherlands)

    Koole, A; Franke, J.P.; de Zeeuw, R.A

    1999-01-01

    We describe the development of an HPLC method with diode-array detection (DAD) for the analysis and identification of 20 substances with anabolic properties, that are considered as potential growth promoters, to be used for the analysis of extracts of calf urine samples. The substances are separated

  17. Bead-based suspension array for simultaneous detection of antibodies against the Rift Valley fever virus nucleocapsid and Gn glycoprotein

    NARCIS (Netherlands)

    Wal, van der F.J.; Achterberg, R.P.; Boer, de S.M.; Boshra, H.; Brun, A.; Maassen, C.B.M.; Kortekaas, J.A.

    2012-01-01

    A multiplex bead-based suspension array was developed that can be used for the simultaneous detection of antibodies against the surface glycoprotein Gn and the nucleocapsid protein N of Rift Valley fever virus (RVFV) in various animal species. The N protein and the purified ectodomain of the Gn prot

  18. Temporal signatures of the Cherenkov light induced by extensive air showers of cosmic rays detected with the Yakutsk array

    Science.gov (United States)

    Ivanov, A. A.; Timofeev, L. V.

    2016-05-01

    We analyze temporal characteristics of signals from the wide field-of-view (WFOV) Cherenkov telescope (CT) detecting extensive air showers (EAS) of cosmic rays (CRs) in coincidence with surface detectors of the Yakutsk array. Our aim is to reveal causal relationships between measured characteristics and physical properties of EAS.

  19. Temporal signatures of the Cherenkov light induced by extensive air showers of cosmic rays detected with the Yakutsk array

    CERN Document Server

    Ivanov, A A

    2016-01-01

    We analyze temporal characteristics of signals from the wide field-of-view (WFOV) Cherenkov telescope (CT) detecting extensive air showers (EAS) of cosmic rays (CR) in coincidence with surface detectors of the Yakutsk array. Our aim is to reveal causal relationships between measured characteristics and physical properties of EAS.

  20. Ordered arrays of Au-nanobowls loaded with Ag-nanoparticles as effective SERS substrates for rapid detection of PCBs.

    Science.gov (United States)

    Chen, Bensong; Meng, Guowen; Zhou, Fei; Huang, Qing; Zhu, Chuhong; Hu, Xiaoye; Kong, Mingguang

    2014-04-11

    Large-scale hexagonally close-packed arrays of Au-nanobowls (Au-NBs) with tens of Ag-nanoparticles (Ag-NPs) dispersed in each bowl (denoted as Ag-NPs@Au-NB arrays) are achieved and utilized as effective surface-enhanced Raman scattering (SERS) substrates. The field enhancement benefiting from the special particle-in-cavity geometrical structure as well as the high density of SERS hot spots located in the sub-10 nm gaps between adjacent Ag-NPs and at the particle-cavity junctions all together contribute to the high SERS activity of the Ag-NPs@Au-NB arrays; meanwhile the ordered morphological features of the Ag-NPs@Au-NB arrays guarantee uniformity and reproducibility of the SERS signals. By modifying the Ag-NPs@Au-NB arrays with mono-6-thio-β-cyclodextrin, the SERS detection sensitivity to 3,3('),4,4(')-tetrachlorobiphenyl (PCB-77, one congener of polychlorinated biphenyls (PCBs, kinds of persistent organic pollutants which represent a global environmental hazard)) can be further improved and a low concentration down to 5 × 10(-7) M can still be examined, showing promising potential for application in rapid detection of trace-level PCBs in the environment.

  1. Specificity of the Linear Array HPV Genotyping Test for detecting human papillomavirus genotype 52 (HPV-52)

    OpenAIRE

    Kocjan, Boštjan; Poljak, Mario; Oštrbenk, Anja

    2015-01-01

    Introduction: HPV-52 is one of the most frequent human papillomavirus (HPV) genotypes causing significant cervical pathology. The most widely used HPV genotyping assay, the Roche Linear Array HPV Genotyping Test (Linear Array), is unable to identify HPV- 52 status in samples containing HPV-33, HPV-35, and/or HPV-58. Methods: Linear Array HPV-52 analytical specificity was established by testing 100 specimens reactive with the Linear Array HPV- 33/35/52/58 cross-reactive probe, but not with the...

  2. High-density SNP arrays improve detection of HER2 amplification and polyploidy in breast tumors

    DEFF Research Database (Denmark)

    Hansen, Thomas V. O.; Vikesaa, Jonas; Buhl, Sine S

    2015-01-01

    ) arrays can provide additional diagnostic power to assess HER2 gene status. METHODS: DNA from 65 breast tumor samples previously diagnosed by HER2 IHC and FISH analysis were blinded and examined for HER2 copy number variation employing SNP array analysis. RESULTS: SNP array analysis identified 24 (37......%) samples with selective amplification or imbalance of the HER2 region in the q-arm of chromosome 17. In contrast, only 15 (23%) tumors were found to have HER2 amplification by IHC and FISH analysis. In total, there was a discrepancy in 19 (29%) samples between SNP array and IHC/FISH analysis. In 12...

  3. Detecting eccentric supermassive black hole binaries with pulsar timing arrays: Resolvable source strategies

    CERN Document Server

    Taylor, S R; Gair, J R; McWilliams, S T

    2015-01-01

    The couplings between supermassive black-hole binaries and their environments within galactic nuclei have been well studied as part of the search for solutions to the final parsec problem. The scattering of stars by the binary or the interaction with a circumbinary disk may efficiently drive the system to sub-parsec separations, allowing the binary to enter a regime where the emission of gravitational-waves can drive it to merger within a Hubble time. However, these interactions can also affect the orbital parameters of the binary. In particular, they may drive an increase in binary eccentricity which survives until the system's gravitational-wave signal enters the pulsar-timing array band. Therefore, if we can measure the eccentricity from observed signals, we can potentially deduce some of the properties of the binary environment. To this end, we build on previous techniques to present a general Bayesian pipeline with which we can detect and estimate the parameters of an eccentric supermassive black-hole bi...

  4. Arrays of Ultrathin CdS Nanoflakes with High-Energy Surface for Efficient Gas Detection.

    Science.gov (United States)

    Liu, Xiao-Hua; Yin, Peng-Fei; Kulinich, Sergei A; Zhou, Yu-Zhu; Mao, Jing; Ling, Tao; Du, Xi-Wen

    2017-01-11

    It is fascinating and challenging to endow conventional materials with unprecedented properties. For instance, cadmium sulfide (CdS) is an important semiconductor with excellent light response; however, its potential in gas-sensing was underestimated owing to relatively low chemical activity and poor electrical conductivity. Herein, we demonstrate that an ideal architecture, ultrathin nanoflake arrays (NFAs), can improve significantly gas-sensing properties of CdS material. The CdS NFAs are grown directly on the interdigitated electrode to expose large surface area. Their thickness is reduced below the double Debye length of CdS, permitting to achieve a full depletion of carriers. Particularly, the prepared CdS nanoflakes are enclosed with high-energy {0001} facets exposed, which provides more active sites for gas adsorption. Moreover, the NFAs exhibit the light-trapping effect, which further enhances their gas sensitivity. As a result, the as-prepared CdS NFAs demonstrate excellent gas-sensing and light-response properties, thus being capable of dual gas and light detection.

  5. Label-Free Detection of Cardiac Troponin-I Using Carbon Nanofiber Based Nanoelectrode Arrays

    Science.gov (United States)

    Periyakaruppan, Adaikkappan; Koehne, Jessica Erin; Gandhiraman, Ram P.; Meyyappan, M.

    2013-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. A carbon nanofiber (CNF) multiplexed array has been fabricated with 9 sensing pads, each containing 40,000 carbon nanofibers as nanoelectrodes. Here, we report the use of vertically aligned CNF nanoelectrodes for the detection of cardiac Troponin-I for the early diagnosis of myocardial infarction. Antibody, antitroponin, probe immobilization and subsequent binding to human cardiac troponin-I were characterized using electrochemical impedance spectroscopy and cyclic voltammetry techniques. Each step of the modification process resulted in changes in electrical capacitance or resistance to charge transfer due to the changes at the electrode surface upon antibody immobilization and binding to the specific antigen. This sensor demonstrates high sensitivity, down to 0.2 ng/mL, and good selectivity making this platform a good candidate for early stage diagnosis of myocardial infarction.

  6. Velocity-resolved hot water emission detected toward HL Tau with the Submillimeter Array

    CERN Document Server

    Kristensen, Lars E; Wilner, David; Salyk, Colette

    2016-01-01

    Using the Submillimeter Array (SMA) on Mauna Kea, the H2-16O 10_2,9-9_3,6 transition (E_up=1863K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blue-shifted by 15 km/s with respect to the source velocity, and it has a FWHM of 20 km/s. The emission is tentatively resolved and extends ~3-4" over the sky (~2 beams), or ~500 AU at the distance of Taurus. The velocity offset, and to a lesser degree the spatial extent of the emission, shows that the line originates in the protostellar jet or wind. This result suggests that at least some water emission observed toward embedded sources, and perhaps also disk sources, with Herschel and Spitzer contains a wind or jet component, which is crucial for interpreting these data. These pathfinder observations done with the SMA opens a new window to studying the origin of water emission with e.g. ALMA, thus providing new insights into where water is in protostellar systems.

  7. High-resolution focal plane array IR detection modules and digital signal processing technologies at AIM

    Science.gov (United States)

    Cabanski, Wolfgang A.; Breiter, Rainer; Koch, R.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Eberhardt, Kurt; Oelmaier, Reinhard; Schneider, Harald; Walther, Martin

    2000-07-01

    Full video format focal plane array (FPA) modules with up to 640 X 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates > 100 Hz together with state of the art thermal resolution NETD rates of 30 - 60 Hz and provide thermal resolutions of NETD exchangeability of the units. New modular image processing hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to be developed to accomplish for the high data rates of up to 18 M pixels/s with 14-bit deep data, allowing to take into account nonlinear effects to access the full NETD by accurate reduction of residual fixed pattern noise. The main features of these modules are summarized together with measured performance data for long range detection systems with moderately fast to slow F-numbers like F/2.0 - F/3.5. An outlook shows most recent activities at AIM, heading for multicolor and faster frame rate detector modules based on MCT devices.

  8. [HPV genotypes prevalence in México and worldwide detected by Linear Array].

    Science.gov (United States)

    Flores-Miramontes, María G; Torres-Reyes, Luis A; Aguilar-Lemarroy, Adriana; Vallejo-Ruíz, Verónica; Piña-Sánchez, Patricia; Cortés-Gutiérrez, Elva; Reyes-Leyva, Julio; Jave-Suárez, Luis Felipe

    2015-01-01

    Infection with human papillomavirus (HPV) is the main factor associated with the development of cervical cancer (CC). Knowing about the prevalence of HPVs at different stages in the development of CC is important for determining the HPV oncogenic risk, the development of screening strategies, the evaluation of prevention programs, and also for vaccine designing. This paper is a meta-analysis of HPV prevalence worldwide and in Mexico from studies using the Linear Array® HPV Genotyping Test as a diagnostic test (it is the commercial test that, up to date, identifies the largest number of HPV genotypes in a single sample) in DNA of cervical samples from women with normal cytology, with low grade squamous intraepithelial lesions (LGSIL), with high grade squamous intraepithelial lesions (HGSIL) and with CC. The most prevalent genotypes after HPV-16 and -18 in women with CC varies depending on geographic region, which supports the need to develop detection and prevention strategies according to the characteristics of the population.

  9. Specific detection of oxytetracycline using DNA aptamer-immobilized interdigitated array electrode chip

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Seok; Niazi, Javed H. [School of Life Sciences and Biotechnology, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Gu, Man Bock [School of Life Sciences and Biotechnology, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-701 (Korea, Republic of)], E-mail: mbgu@korea.ac.kr

    2009-02-23

    An electrochemical sensing system for oxytetracycline (OTC) detection was developed using ssDNA aptamer immobilized on gold interdigitated array (IDA) electrode chip. A highly specific ssDNA aptamer that bind to OTC with high affinity was employed to discriminate other tetracyclines (TCs), such as doxycycline (DOX) and tetracycline (TET). The immobilized thiol-modified aptamer on gold electrode chip served as a biorecognition element for the target molecules and the electrochemical signals generated from interactions between the aptamers and the target molecules was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV). The current decrease due to the interference of bound OTC, DOX or TET was analyzed with the electron flow produced by a redox reaction between ferro- and ferricyanide. The specificity of developed EC-biosensor for OTC was highly distinguishable from the structurally similar antibiotics (DOX and TET). The dynamic range was determined to be 1-100 nM of OTC concentration in semi-logarithmic coordinates.

  10. Array high-sensitivity room temperature coil system for SNMR detection in shallow depth

    Science.gov (United States)

    Lin, Tingting; Xie, Kunyu; Zhang, Siyuan; Zhao, Jing; Lin, Jun

    2017-01-01

    The noninvasive method of surface nuclear magnetic resonance (SNMR) is a geophysical technique that is directly sensitive to hydrogen protons, besides it can exploit the NMR phenomenon for a quantitative determination of the subsurface groundwater distribution. Traditionally, SNMR utilizes large surface coils for both transmitting excitation pulses and recording the groundwater response. While, in recent research, a low Tc-SQUIDs is taken as a new sensor to replace the large receiving coil (Rx), which performing the best sensitivity for the shallow depth. Nevertheless, SQUID is with the problems of flux trapping and operational difficulties. In this paper, we introduce a room temperature coil system. A Cu coil with diameter of 1 m and a low noise preamplifier was systematically investigated and reached a sensitivity of 0.2fT/Hz1/2.Four preamplifiers are chosen for optimizing the pickup coils. The resolution studies for the array coil systems were performed, and the optimum distance between the adjacent pickup coils to achieve a better experimental results especially for the shallow depth. Our study enable the further use of the room temperature coil for SNMR shallow depth detections.

  11. Visual detection of 2,4,6-trinitrotolune by molecularly imprinted colloidal array photonic crystal.

    Science.gov (United States)

    Lu, Wei; Asher, Sanford A; Meng, Zihui; Yan, Zequn; Xue, Min; Qiu, Lili; Yi, Da

    2016-10-05

    We developed a photonic crystal (PhC) sensor for the quantification of 2,4,6-trinitrotoluene (TNT) in solution. Monodisperse (210nm in diameter) molecularly imprinted colloidal particles (MICs) for TNT were prepared by the emulsion polymerization of methyl methacrylate and acrylamide in the presence of TNT as a template. The MICs were then self-assembled into close-packed opal PhC films. The adsorption capacity of the MICs for TNT was 64mg TNT/g. The diffraction from the PhC depended on the TNT concentration in a methanol/water (3/2, v/v) potassium dihydrogen phosphate buffer solution (pH=7.0, 30mM). The limit of detection (LOD) of the sensor was 1.03μg. The color of the molecularly imprinted colloidal array (MICA) changed from green to red with an 84nm diffraction red shift when the TNT concentration increased to 20mM. The sensor response time was 3min. The PhC sensor was selective for TNT compared to similar compounds such as 2,4,6-trinitrophenol, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2-nitromesitylene, 4-nitrotoluene, 2-nitrotoluene, 1,3-dinitrobenzene, methylbenzene, 4-nitrophenol, 2-nitroaniline, 3-aminophenol and 3-nitroaniline. The sensor showed high stability with little response change after three years storage. This sensor technology might be useful for the visual determination of TNT.

  12. Velocity-resolved Hot Water Emission Detected toward HL Tau with the Submillimeter Array

    Science.gov (United States)

    Kristensen, Lars E.; Brown, Joanna M.; Wilner, David; Salyk, Colette

    2016-05-01

    Using the Submillimeter Array (SMA) on Mauna Kea, the {{{H}}}216{{O}} {10}{2,9}-9{}{3,6} transition ({E}{{up}} = 1863 K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blueshifted by 20 km s-1 with respect to the source velocity, and it has a FWHM of 25 km s-1. The emission is tentatively resolved and extends ˜3″-4″ over the sky (˜2 beams), or ˜500 au at the distance of Taurus. The velocity offset, and to a lesser degree the spatial extent of the emission, show that the line originates in the protostellar jet or wind. This result suggests that at least some water emission observed with Herschel and Spitzer toward embedded sources, and perhaps also disk sources, contains a wind or jet component, which is crucial for interpreting these data. These pathfinder observations done with the SMA open a new window into studying the origin of water emission with e.g., ALMA, thus providing new insights into where water is in protostellar systems.

  13. Label-free electrochemical impedance detection of kinase and phosphatase activities using carbon nanofiber nanoelectrode arrays

    Science.gov (United States)

    Li, Yifen; Syed, Lateef; Liu, Jianwei; Hua, Duy H.; Li, Jun

    2012-01-01

    We demonstrate the feasibility of a label-free electrochemical method to detect the kinetics of phosphorylation and dephosphorylation of surface-attached peptides catalyzed by kinase and phosphatase, respectively. The peptides with a sequence specific to c-Src tyrosine kinase and protein tyrosine phosphatase 1B (PTP1B) were first validated with ELISA-based protein tyrosine kinase assay and then functionalized on vertically aligned carbon nanofiber (VACNF) nanoelectrode arrays (NEAs). Real-time electrochemical impedance spectroscopy (REIS) measurements showed reversible impedance changes upon the addition of c-Src kinase and PTP1B phosphatase. Only a small and unreliable impedance variation was observed during the peptide phosphorylation, but a large and fast impedance decrease was observed during the peptide dephosphorylation at different PTP1B concentrations. The REIS data of dephosphorylation displayed a well-defined exponential decay following the Michaelis-Menten heterogeneous enzymatic model with a specific constant, kcat/Km, of (2.1 ± 0.1) × 107 M−1 s−1. Consistent values of the specific constant was measured at PTP1B concentration varying from 1.2 to 2.4 nM with the corresponding electrochemical signal decay constant varying from 38.5 to 19.1 s. This electrochemical method can be potentially used as a label-free method for profiling enzyme activities in fast reactions. PMID:22935373

  14. Aircraft Aerodynamic Parameter Detection Using Micro Hot-Film Flow Sensor Array and BP Neural Network Identification

    Science.gov (United States)

    Que, Ruiyi; Zhu, Rong

    2012-01-01

    Air speed, angle of sideslip and angle of attack are fundamental aerodynamic parameters for controlling most aircraft. For small aircraft for which conventional detecting devices are too bulky and heavy to be utilized, a novel and practical methodology by which the aerodynamic parameters are inferred using a micro hot-film flow sensor array mounted on the surface of the wing is proposed. A back-propagation neural network is used to model the coupling relationship between readings of the sensor array and aerodynamic parameters. Two different sensor arrangements are tested in wind tunnel experiments and dependence of the system performance on the sensor arrangement is analyzed. PMID:23112638

  15. Saturation effects in heterodyne detection with Geiger-mode InGaAs avalanche photodiode detector arrays.

    Science.gov (United States)

    Luu, Jane X; Jiang, Leaf A

    2006-06-01

    We report, to the best of our knowledge, the first demonstration of heterodyne detection of a glint target using an InGaAs avalanche photodiode detector (APD) array in the Geiger mode. Due to the finite number of pixels, all such photon-counting arrays necessarily suffer from saturation effects. At large photon fluxes, saturation of the APD degrades the Doppler frequency resolution and the signal-to-noise ratio (SNR). We derive analytical expressions for the Doppler resolution and SNR, taking saturation effects into account. The optimal local oscillator power can be obtained numerically from the SNR expression.

  16. Rapid mutation detection in complex genes by heteroduplex analysis with capillary array electrophoresis.

    Science.gov (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Esteban-Cardeñosa, Eva; Lastra, Enrique; García-Girón, Carlos; Miner, Cristina

    2005-06-01

    Mutational analysis of large multiexon genes without prevalent mutations is a laborious undertaking that requires the use of a high-throughput scanning technique. The Human Genome Project has enabled the development of powerful techniques for mutation detection in large multiexon genes. We have transferred heteroduplex analysis (HA) by conformation-sensitive gel electrophoresis of the two major breast cancer (BC) predisposing genes, BRCA1 and BRCA2, to a multicapillary DNA sequencer in order to increase the throughput of this technique. This new method that we have called heteroduplex analysis by capillary array electrophoresis (HA-CAE) is based on the use of multiplex-polymerase chain reaction (PCR), different fluorescent labels and HA in a 16-capillary DNA sequencer. To date, a total of 114 different DNA sequence variants (19 insertions/deletions and 95 single-nucleotide substitutions - SNS) of BRCA1 and BRCA2 from 431 unrelated BC families have been successfully detected by HA-CAE. In addition, we have optimized the multiplex-PCR conditions for the colorectal cancer genes MLH1 and MSH2 in order to analyze them by HA-CAE. Both genes have been amplified in 13 multiplex groups, which contain the 35 exons, and their corresponding flanking intronic sequences. MLH1 and MSH2 have been analyzed in nine hereditary nonpolyposis colorectal cancer patients, and we have found six different DNA changes: one complex deletion/insertion mutation in MLH1 exon 19 and another five SNS. Only the complex mutation and one SNS may be classified as cancer-prone mutations. Our experience has revealed that HA-CAE is a simple, fast, reproducible and sensitive method to scan the sequences of complex genes.

  17. Multiple Break-Points Detection in Array CGH Data via the Cross-Entropy Method.

    Science.gov (United States)

    Priyadarshana, W J R M; Sofronov, Georgy

    2015-01-01

    Array comparative genome hybridization (aCGH) is a widely used methodology to detect copy number variations of a genome in high resolution. Knowing the number of break-points and their corresponding locations in genomic sequences serves different biological needs. Primarily, it helps to identify disease-causing genes that have functional importance in characterizing genome wide diseases. For human autosomes the normal copy number is two, whereas at the sites of oncogenes it increases (gain of DNA) and at the tumour suppressor genes it decreases (loss of DNA). The majority of the current detection methods are deterministic in their set-up and use dynamic programming or different smoothing techniques to obtain the estimates of copy number variations. These approaches limit the search space of the problem due to different assumptions considered in the methods and do not represent the true nature of the uncertainty associated with the unknown break-points in genomic sequences. We propose the Cross-Entropy method, which is a model-based stochastic optimization technique as an exact search method, to estimate both the number and locations of the break-points in aCGH data. We model the continuous scale log-ratio data obtained by the aCGH technique as a multiple break-point problem. The proposed methodology is compared with well established publicly available methods using both artificially generated data and real data. Results show that the proposed procedure is an effective way of estimating number and especially the locations of break-points with high level of precision. Availability: The methods described in this article are implemented in the new R package breakpoint and it is available from the Comprehensive R Archive Network at http://CRAN.R-project.org/package=breakpoint.

  18. An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide

    Science.gov (United States)

    Hu, Xiaoye; Zheng, Peng; Meng, Guowen; Huang, Qing; Zhu, Chuhong; Han, Fangming; Huang, Zhulin; Li, Zhongbo; Wang, Zhaoming; Wu, Nianqiang

    2016-09-01

    An ordered array of hierarchically-structured core-nanosphere@space-layer@shell-nanoparticles has been fabricated for surface-enhanced Raman scattering (SERS) detection. To fabricate this hierarchically-structured chip, a long-range ordered array of Au/Ag-nanospheres is first patterned in the nano-bowls on the planar surface of ordered nanoporous anodic titanium oxide template. A ultra-thin alumina middle space-layer is then conformally coated on the Au/Ag-nanospheres, and Ag-nanoparticles are finally deposited on the surface of the alumina space-layer to form an ordered array of Au/Ag-nanosphere@Al2O3-layer@Ag-nanoparticles. Finite-difference time-domain simulation shows that SERS hot spots are created between the neighboring Ag-nanoparticles. The ordered array of hierarchical nanostructures is used as the SERS-substrate for a trial detection of methyl parathion (a pesticide) in water and a limit of detection of 1 nM is reached, indicating its promising potential in rapid monitoring of organic pollutants in aquatic environment.

  19. Multiplex detection of B-type natriuretic peptide, cardiac troponin I and C-reactive protein with photonic suspension array.

    Directory of Open Access Journals (Sweden)

    Wenbin Lu

    Full Text Available A novel photonic suspension array has been developed for multiplex immunoassay. The carriers of this array were silica colloidal crystal beads (SCCBs. The codes of these carriers have characteristic reflection peaks originating from their structural periodicity; therefore they do not suffer from fading, bleaching, quenching or chemical instability. In addition, the fluorescence background of SCCBs is negligible because no fluorescence materials or dyes are involved. With a sandwich method, the proposed suspension array was used for simultaneous multiplex detection of heart failure (HF and coronary heart disease (CAD biomarkers in one test tube. The results showed that the three biomarkers: cardiac troponin I (cTnI, C-reactive protein (CRP and B-type natriuretic peptide (BNP could be assayed in the ranges of 0.1-500 ng/ml, 1-500 mg/L and 0.02-50 ng/ml with detection limits of 0.01 ng/ml, 0.36 mg/L and 0.004 ng/ml at 3σ, respectively. There were no significant differences between the photonic suspension array and traditional parallel single-analyte test. This novel method demonstrated acceptable accuracy, high detection sensitivity and reproducibility and excellent storage stability. This technique provides a new strategy for low cost, automated, and simultaneous multiplex immunoassays of bio-markers.

  20. Rapid detection of genomic imbalances using micro-arrays consisting of pooled BACs covering all human chromosome arms.

    Science.gov (United States)

    Knijnenburg, Jeroen; van der Burg, Marja; Nilsson, Philomeen; Ploos van Amstel, Hans Kristian; Tanke, Hans; Szuhai, Károly

    2005-10-12

    A strategy is presented to select, pool and spot human BAC clones on an array in such a way that each spot contains five well performing BAC clones, covering one chromosome arm. A mini-array of 240 spots was prepared representing all human chromosome arms in a 5-fold as well as some controls, and used for comparative genomic hybridization (CGH) of 10 cell lines with aneusomies frequently found in clinical cytogenetics and oncology. Spot-to-spot variation within five replicates was below 6% and all expected abnormalities were detected 100% correctly. Sensitivity was such that replacing one BAC clone in a given spot of five by a BAC clone from another chromosome, thus resulting in a change in ratio of 20%, was reproducibly detected. Incubation time of the mini-array was varied and the fluorescently labelled target DNA was diluted. Typically, aneusomies could be detected using 30 ng of non-amplified random primed labelled DNA amounts in a 4 h hybridization reaction. Potential application of these mini-arrays for genomic profiling of disseminated tumour cells or of blastomeres for preimplantation genetic diagnosis, using specially designed DNA amplification methods, are discussed.

  1. X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation

    Directory of Open Access Journals (Sweden)

    Martínez F

    2007-11-01

    Full Text Available Abstract Background Aproximately 5–10% of cases of mental retardation in males are due to copy number variations (CNV on the X chromosome. Novel technologies, such as array comparative genomic hybridization (aCGH, may help to uncover cryptic rearrangements in X-linked mental retardation (XLMR patients. We have constructed an X-chromosome tiling path array using bacterial artificial chromosomes (BACs and validated it using samples with cytogenetically defined copy number changes. We have studied 54 patients with idiopathic mental retardation and 20 controls subjects. Results Known genomic aberrations were reliably detected on the array and eight novel submicroscopic imbalances, likely causative for the mental retardation (MR phenotype, were detected. Putatively pathogenic rearrangements included three deletions and five duplications (ranging between 82 kb to one Mb, all but two affecting genes previously known to be responsible for XLMR. Additionally, we describe different CNV regions with significant different frequencies in XLMR and control subjects (44% vs. 20%. Conclusion This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients.

  2. Final Scientific Report, Integrated Seismic Event Detection and Location by Advanced Array Processing

    Energy Technology Data Exchange (ETDEWEB)

    Kvaerna, T.; Gibbons. S.J.; Ringdal, F; Harris, D.B.

    2007-01-30

    primarily the result of spurious identification and incorrect association of phases, and of excessive variability in estimates for the velocity and direction of incoming seismic phases. The mitigation of these causes has led to the development of two complimentary techniques for classifying seismic sources by testing detected signals under mutually exclusive event hypotheses. Both of these techniques require appropriate calibration data from the region to be monitored, and are therefore ideally suited to mining areas or other sites with recurring seismicity. The first such technique is a classification and location algorithm where a template is designed for each site being monitored which defines which phases should be observed, and at which times, for all available regional array stations. For each phase, the variability of measurements (primarily the azimuth and apparent velocity) from previous events is examined and it is determined which processing parameters (array configuration, data window length, frequency band) provide the most stable results. This allows us to define optimal diagnostic tests for subsequent occurrences of the phase in question. The calibration of templates for this project revealed significant results with major implications for seismic processing in both automatic and analyst reviewed contexts: • one or more fixed frequency bands should be chosen for each phase tested for. • the frequency band providing the most stable parameter estimates varies from site to site and a frequency band which provides optimal measurements for one site may give substantially worse measurements for a nearby site. • slowness corrections applied depend strongly on the frequency band chosen. • the frequency band providing the most stable estimates is often neither the band providing the greatest SNR nor the band providing the best array gain. For this reason, the automatic template location estimates provided here are frequently far better than those obtained by

  3. Resolution and signal-to-noise ratio improvement in confocal fluorescence microscopy using array detection and maximum-likelihood processing

    Science.gov (United States)

    Kakade, Rohan; Walker, John G.; Phillips, Andrew J.

    2016-08-01

    Confocal fluorescence microscopy (CFM) is widely used in biological sciences because of its enhanced 3D resolution that allows image sectioning and removal of out-of-focus blur. This is achieved by rejection of the light outside a detection pinhole in a plane confocal with the illuminated object. In this paper, an alternative detection arrangement is examined in which the entire detection/image plane is recorded using an array detector rather than a pinhole detector. Using this recorded data an attempt is then made to recover the object from the whole set of recorded photon array data; in this paper maximum-likelihood estimation has been applied. The recovered object estimates are shown (through computer simulation) to have good resolution, image sectioning and signal-to-noise ratio compared with conventional pinhole CFM images.

  4. Alternative splicing and differential gene expression in colon cancer detected by a whole genome exon array

    Directory of Open Access Journals (Sweden)

    Sugnet Charles

    2006-12-01

    Full Text Available Abstract Background Alternative splicing is a mechanism for increasing protein diversity by excluding or including exons during post-transcriptional processing. Alternatively spliced proteins are particularly relevant in oncology since they may contribute to the etiology of cancer, provide selective drug targets, or serve as a marker set for cancer diagnosis. While conventional identification of splice variants generally targets individual genes, we present here a new exon-centric array (GeneChip Human Exon 1.0 ST that allows genome-wide identification of differential splice variation, and concurrently provides a flexible and inclusive analysis of gene expression. Results We analyzed 20 paired tumor-normal colon cancer samples using a microarray designed to detect over one million putative exons that can be virtually assembled into potential gene-level transcripts according to various levels of prior supporting evidence. Analysis of high confidence (empirically supported transcripts identified 160 differentially expressed genes, with 42 genes occupying a network impacting cell proliferation and another twenty nine genes with unknown functions. A more speculative analysis, including transcripts based solely on computational prediction, produced another 160 differentially expressed genes, three-fourths of which have no previous annotation. We also present a comparison of gene signal estimations from the Exon 1.0 ST and the U133 Plus 2.0 arrays. Novel splicing events were predicted by experimental algorithms that compare the relative contribution of each exon to the cognate transcript intensity in each tissue. The resulting candidate splice variants were validated with RT-PCR. We found nine genes that were differentially spliced between colon tumors and normal colon tissues, several of which have not been previously implicated in cancer. Top scoring candidates from our analysis were also found to substantially overlap with EST-based bioinformatic

  5. A bead-based suspension array for the multiplexed detection of begomoviruses and their whitefly vectors

    NARCIS (Netherlands)

    Brunschot, van S.L.; Bergervoet, J.H.W.; Pagendam, D.E.; Weerdt, de M.; Geering, A.D.W.; Drenth, A.; Vlugt, van der R.A.A.

    2014-01-01

    Bead-based suspension array systems enable simultaneous fluorescence-based identification of multiple nucleic acid targets in a single reaction. This study describes the development of a novel approach to plant virus and vector diagnostics, a multiplexed 7-plex array that comprises a hierarchical

  6. Equivalent Joint Space-Time Multiuser Detection for Uplink ISI-Corrupted Multicarrier CDMA Systems with Arbitrary Antenna Arrays

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The multicarrier code division multiple access (MC-CDMA) systems without cyclic prefix (CP) hold a finespectral efficiency though they are unavoidably corrupted by the intersymbol interference (ISI) over the finite impulseresponse (FIR) channel. We call MC-CDMA systems without CP the ISI-corrupted MC-CDMA systems in some sense.Considering the fact that combining antenna arrays with so-called ISI-corrupted MC-CDMA systems is advantageous insuppressing cochannel interference in cellular communication systems, this paper investigates ISI-corrupted MC-CDMAsystems with base station antenna arrays. Joint space-time multiuser detection (MUD) schemes for DS-CDMA systemswith antenna arrays have drawn much attention recently. Based upon them, we can derive the equivalent joint spatial-temporal MUD scheme for ISI-corrupted MC-CDMA systems with antenna arrays. In order to achieve this goal, anequivalent space-time estimation method of uplink vector channel is first derived for the ISI-corrupted MC-CDMA systemwith the arbitrary antenna array over frequency-selective fading channels. Then, based on the estimated equivalent space-time channel, an equivalent joint space-time multiuser detector is constructed. Computer simulations illustrate that ouralgorithm is more robust against noise and can well mitigate multiple access interference (MAI) in multiuser scenarios.

  7. Single-molecule detection of protein efflux from microorganisms using fluorescent single-walled carbon nanotube sensor arrays

    Science.gov (United States)

    Landry, Markita Patricia; Ando, Hiroki; Chen, Allen Y.; Cao, Jicong; Kottadiel, Vishal Isaac; Chio, Linda; Yang, Darwin; Dong, Juyao; Lu, Timothy K.; Strano, Michael S.

    2017-05-01

    A distinct advantage of nanosensor arrays is their ability to achieve ultralow detection limits in solution by proximity placement to an analyte. Here, we demonstrate label-free detection of individual proteins from Escherichia coli (bacteria) and Pichia pastoris (yeast) immobilized in a microfluidic chamber, measuring protein efflux from single organisms in real time. The array is fabricated using non-covalent conjugation of an aptamer-anchor polynucleotide sequence to near-infrared emissive single-walled carbon nanotubes, using a variable chemical spacer shown to optimize sensor response. Unlabelled RAP1 GTPase and HIV integrase proteins were selectively detected from various cell lines, via large near-infrared fluorescent turn-on responses. We show that the process of E. coli induction, protein synthesis and protein export is highly stochastic, yielding variability in protein secretion, with E. coli cells undergoing division under starved conditions producing 66% fewer secreted protein products than their non-dividing counterparts. We further demonstrate the detection of a unique protein product resulting from T7 bacteriophage infection of E. coli, illustrating that nanosensor arrays can enable real-time, single-cell analysis of a broad range of protein products from various cell types.

  8. A reusable laser wrapped graphene-Ag array based SERS sensor for trace detection of genomic DNA methylation.

    Science.gov (United States)

    Ouyang, Lei; Hu, Yaowu; Zhu, Lihua; Cheng, Gary J; Irudayaraj, Joseph

    2017-06-15

    Methylation is an important epigenetic DNA modification that governs gene expression. The genomic level of methylated DNA and its derivatives may serve as important indicators for the initiation and progression of cancers among other diseases. In this effort we propose a new laser wrapped graphene-Ag array as a highly sensitive Surface-enhanced Raman spectroscopy (SERS) sensor for the detection of methylated DNA (5-methylcytosine, 5mC) and its oxidation derivatives namely 5-hydroxymethylcytosine (5-hmC) and 5-carboxylcytosine (5-caC). Excellent sensitivity and reproducibility were achieved with the laser wrapped graphene-Ag array as a substrate, with the graphene layer acting as an enhancer of the SERS signal due to the effective coupling of the electromagnetic field. In summary, fast (less than 60min) and sensitive (at a limit of detection 0.2pgμL(-1), ie. 1.8pmolL(-1)) detection of methylated DNA and its derivatives was realized with the ability to distinguish methylation levels from a mixture at 0.1%. The sensitive and accurate detection in DNA extracted from cells was also accomplished. Furthermore our graphene wrapped approach circumvents the direct interaction between Ag array and the analytes, thus improving the reusability of the SERS substrate even after five cycles of use. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jiewu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China); Adeloju, Samuel B., E-mail: sam.adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China)

    2014-01-27

    Graphical abstract: -- Highlights: •Successfully synthesised highly-ordered gold nanowires array with an AAO template. •Fabricated an ultra-sensitive glucose nanobiosensor with the gold nanowires array. •Achieved sensitivity as high as 379.0 μA cm{sup −2} mM{sup −1} and detection limit as low as 50 nM. •Achieved excellent anti-interference with aid of Nafion membrane towards UA and AA. •Enabled successful detection and quantification of glucose in human blood serum. -- Abstract: A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO{sub x}) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA–BSA–GLA–GO{sub x} nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm{sup −2} mM{sup −1} for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5–6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples.

  10. Direct detection of transcription factors in cotyledons during seedling development using sensitive silicon-substrate photonic crystal protein arrays.

    Science.gov (United States)

    Jones, Sarah I; Tan, Yafang; Shamimuzzaman, Md; George, Sherine; Cunningham, Brian T; Vodkin, Lila

    2015-03-01

    Transcription factors control important gene networks, altering the expression of a wide variety of genes, including those of agronomic importance, despite often being expressed at low levels. Detecting transcription factor proteins is difficult, because current high-throughput methods may not be sensitive enough. One-dimensional, silicon-substrate photonic crystal (PC) arrays provide an alternative substrate for printing multiplexed protein microarrays that have greater sensitivity through an increased signal-to-noise ratio of the fluorescent signal compared with performing the same assay upon a traditional aminosilanized glass surface. As a model system to test proof of concept of the silicon-substrate PC arrays to directly detect rare proteins in crude plant extracts, we selected representatives of four different transcription factor families (zinc finger GATA, basic helix-loop-helix, BTF3/NAC [for basic transcription factor of the NAC family], and YABBY) that have increasing transcript levels during the stages of seedling cotyledon development. Antibodies to synthetic peptides representing the transcription factors were printed on both glass slides and silicon-substrate PC slides along with antibodies to abundant cotyledon proteins, seed lectin, and Kunitz trypsin inhibitor. The silicon-substrate PC arrays proved more sensitive than those performed on glass slides, detecting rare proteins that were below background on the glass slides. The zinc finger transcription factor was detected on the PC arrays in crude extracts of all stages of the seedling cotyledons, whereas YABBY seemed to be at the lower limit of their sensitivity. Interestingly, the basic helix-loop-helix and NAC proteins showed developmental profiles consistent with their transcript patterns, indicating proof of concept for detecting these low-abundance proteins in crude extracts.

  11. A sensitive method to detect the hepatitis B virus mutations by using solid phase PCR on oligonucleotide array

    Institute of Scientific and Technical Information of China (English)

    YAN QIN LU; JIN XIANG HAN; ZHONG LIN SHEN; CHUAN XI WANG

    2006-01-01

    A sensitive method based on solid phase PCR on oligonucleotide array was established to detect two point mutations 1896G-A and 1901G-A in hepatitis B virus (HBV) DNA, in which 6 probes including these two point mutations were immobilized on modified glass slides through 5' terminal linker,while the 3' terminal was made to be free. The mutated loci were designed to locate on the last nucleotides of 3' terminal respectively, and the positive control probes lacked the last nucleotide of 3' terminal in comparison with the probes used for detection. Probes fixed on oligonucleotide array were also the solid phase amplification primers. One pair of liquid primers was used to amplify the short template product from whole HBV DNA. Using target DNA as template, the solid primers were extended under the action of Taq DNA polymerase and incorporated with Cy-3dCTP as marker. During the thermal cycling reaction,probes served as solid phase amplification primers and amplification products bound to the oligonucleotide array, which could be visualized by incorporation with fluorescent dyes. After amplification, the oligonucleotide array was washed, performed with laser scanning, and then used for quantitative analysis to obtain the information for mutations. The hybridization results were compared with DNA sequencing. It was demonstrated that in case of sample A, the ratios of fluorescence intensities in wide type and in the muin these two loci. These results correlated to those obtained from DNA sequencing analysis in which the fluorescence intensity ratios in wide type and in the mutated types of 1996G-A and 1901D-A mutations in using solid phase PCR based on oligonucleotide array appears to be a sensitive and promising way to detect mutations with low-density.

  12. Electrochemical genosensor array for the simultaneous detection of multiple high-risk human papillomavirus sequences in clinical samples

    Energy Technology Data Exchange (ETDEWEB)

    Civit, Laia [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Fragoso, Alex, E-mail: alex.fragoso@urv.cat [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Hoelters, Sebastian; Duerst, Matthias [Department for Gynecology, Jena University Hospital, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); O' Sullivan, Ciara K., E-mail: ciara.osullivan@urv.cat [Nanobiotechnology and Bioanalysis Group, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Institucio Catalana de Recerca i Estudis Avancats, Passeig Lluis Companys 23, 08010 Barcelona (Spain)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer High-risk human papillomavirus is detected in virtually all-invasive cervical cancers. Black-Right-Pointing-Pointer Electrochemical genosensor for simultaneous detection of multiple high-risk HPV applied to cervical scrape samples. Black-Right-Pointing-Pointer Excellent correlation with HPV genotyping carried out within a hospital laboratory. - Abstract: An electrochemical genosensor array for the simultaneous detection of three high-risk human papillomavirus (HPV) DNA sequences, HPV16, 18 and 45, exhibiting high sensitivity and selectivity is presented. The electrodes of a 4 Multiplication-Sign 4 array were modified via co-immobilization of a 1:100 (mol/mol) mixture of a thiolated probe and an oligoethyleneglycol-terminated bipodal thiol. Detection of synthetic and PCR products was carried out in a sandwich type format, with the target hybridized between a surface immobilized probe and a horseradish peroxidase-labelled secondary reporter probe. The detection limits obtained in the detection of each individual target were in the pM range, allowing the application of this sensor for the detection of samples obtained from PCR amplification of cervical scrape samples. The results obtained exhibited an excellent correlation with the HPV genotyping carried out within a hospital laboratory. Multiplexing and cross-reactivity studies demonstrated high selectivity over potential interfering sequences, facilitating application of the developed platform for the high-throughput screening of multiple high-risk DNA sequences.

  13. A Pt-Doped TiO2 Nanotube Arrays Sensor for Detecting SF6 Decomposition Products

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2013-10-01

    Full Text Available The detection of partial discharge and analysis of SF6 gas components in gas-insulated switchgear (GIS is important for the diagnosis and operating state assessment of power equipment. The use of a Pt-doped TiO2 nanotube arrays sensor for detecting sulfur hexafluoride (SF6 decomposition products is proposed in this paper. The electrochemical pulse deposition method is employed to prepare the sensor array. The sensor’s response to the main characteristic gaseous decomposition products of SF6 is evaluated. The gas sensing characteristic curves of the Pt-doped TiO2 nanotube sensor and intrinsic TiO2 nanotube arrays sensor are compared. The mechanism of the sensitive response is discussed. Test results showed that the Pt-doped nanoparticles not only change the gas sensing selectivity of the TiO2 nanotube arrays sensor with respect to the main characteristic SF6 decomposition products, but also reduce the operating temperature of the sensor.

  14. Multi-colorimetric sensor array for detection of explosives in gas and liquid phase

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Alstrøm, Tommy Sonne; Johnsen, C.

    2011-01-01

    . The technology is based on an array of chemoselective compounds immobilized on a solid support. Upon exposure to the analyte in suspicion the colorimetric array changes color. Each chosen compound reacts chemo-selectively with analytes of interest. A change in a color signature indicates the presence of unknown...... explosives and volatile organic compounds (VOCs). We are working towards the selection of compounds that undergo color changes in the presence of explosives and VOCs, as well as the development of an immobilization method for the molecules. Digital imaging of the colorimetric array before and after exposure...

  15. High-Precision Dispensing of Nanoliter Biofluids on Glass Pedestal Arrays for Ultrasensitive Biomolecule Detection.

    Science.gov (United States)

    Chen, Xiaoxiao; Liu, Yang; Xu, QianFeng; Zhu, Jing; Poget, Sébastien F; Lyons, Alan M

    2016-05-04

    Precise dispensing of nanoliter droplets is necessary for the development of sensitive and accurate assays, especially when the availability of the source solution is limited. Conventional approaches are limited by imprecise positioning, large shear forces, surface tension effects, and high costs. To address the need for precise and economical dispensing of nanoliter volumes, we developed a new approach where the dispensed volume is dependent on the size and shape of defined surface features, thus freeing the dispensing process from pumps and fine-gauge needles requiring accurate positioning. The surface we fabricated, called a nanoliter droplet virtual well microplate (nVWP), achieves high-precision dispensing (better than ±0.5 nL or ±1.6% at 32 nL) of 20-40 nL droplets using a small source drop (3-10 μL) on isolated hydrophilic glass pedestals (500 μm on a side) bonded to arrays of polydimethylsiloxane conical posts. The sharp 90° edge of the glass pedestal pins the solid-liquid-vapor triple contact line (TCL), averting the wetting of the glass sidewalls while the fluid is prevented from receding from the edge. This edge creates a sufficiently large energy barrier such that microliter water droplets can be poised on the glass pedestals, exhibiting contact angles greater >150°. This approach relieves the stringent mechanical alignment tolerances required for conventional dispensing techniques, shifting the control of dispensed volume to the area circumscribed by the glass edge. The effects of glass surface chemistry and dispense velocity on droplet volume were studied using optical microscopy and high-speed video. Functionalization of the glass pedestal surface enabled the selective adsorption of specific peptides and proteins from synthetic and natural biomolecule mixtures, such as venom. We further demonstrate how the nVWP dispensing platform can be used for a variety of assays, including sensitive detection of proteins and peptides by fluorescence

  16. Nanotube antibody biosensor arrays for the detection of circulating breast cancer cells

    Science.gov (United States)

    Shao, Ning; Wickstrom, Eric; Panchapakesan, Balaji

    2008-11-01

    Recent reports have shown that nanoscale electronic devices can be used to detect a change in electrical properties when receptor proteins bind to their corresponding antibodies functionalized on the surface of the device, in extracts from as few as ten lysed tumor cells. We hypothesized that nanotube-antibody devices could sensitively and specifically detect entire live cancer cells. We report for the first time a single nanotube field effect transistor array, functionalized with IGF1R-specific and Her2-specific antibodies, which exhibits highly sensitive and selective sensing of live, intact MCF7 and BT474 human breast cancer cells in human blood. Those two cell lines both overexpress IGF1R and Her2, at different levels. Single or small bundle of nanotube devices that were functionalized with IGF1R-specific or Her2-specific antibodies showed 60% decreases in conductivity upon interaction with BT474 or MCF7 breast cancer cells in two µl drops of blood. Control experiments with non-specific antibodies or with MCF10A control breast cells produced a less than 5% decrease in electrical conductivity, illustrating the high sensitivity for whole cell binding by these single nanotube-antibody devices. We postulate that the free energy change due to multiple simultaneous cell-antibody binding events exerted stress along the nanotube surface, decreasing its electrical conductivity due to an increase in band gap. Because the free energy change upon cell-antibody binding, the stress exerted on the nanotube, and the change in conductivity are specific to a specific antigen-antibody interaction; these properties might be used as a fingerprint for the molecular sensing of circulating cancer cells. From optical microscopy observations during sensing, it appears that the binding of a single cell to a single nanotube field effect transistor produced the change in electrical conductivity. Thus we report a nanoscale oncometer with single cell sensitivity with a diameter 1000 times

  17. Innovative Self-Powered and Self-Contained Sensor Array for Separation Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a self-contained, self-powered, robust flight test sensor array for the determination of separation. The proposed system uses...

  18. A Low Cost, Electronically Scanned Array (ESA) Antenna Technology for Aviation Hazard Detection and Avoidance Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project will investigate the feasibility of utilizing ThinKom's low cost electronically scanned array (ESA) antenna concepts to enable affordable...

  19. Exploring Nanostructure Arrays for Single-Cell and Subcellular Manipulation and Detection

    DEFF Research Database (Denmark)

    Buch-Månson, Nina

    these, arrays of vertical nanostructures (NSs) with submicron diametersand microscale lengths are particularly promising and are currently being established as bothhighly sensitive protein arrays and as platforms for manipulations and investigations at thesingle-cell or even subcellular level.To date...... on different NSarray geometries and materials, both through theoretical modeling and experiments.We first seek to improve the fundamental understanding of the cell-NS interface bytheoretical considerations of the energy balance between the cost of membrane deformationaround the NSs and the favorable gain...... in adhesive contact as a cell settles into a NS array. Cellshave both been reported to deform completely into NS arrays or to stay suspended at the NS tipslike tiny fakirs, which have important implications for the possible applications. We show that,in addition to NS density, the energy difference between...

  20. Innovative Self-Powered and Self-Contained Sensor Array for Separation Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a self-contained, self-powered, robust flight test sensor array for the determination of separation. The proposed system uses off the...

  1. SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure.

    Science.gov (United States)

    Zhang, C; Jiang, S Z; Huo, Y Y; Liu, A H; Xu, S C; Liu, X Y; Sun, Z C; Xu, Y Y; Li, Z; Man, B Y

    2015-09-21

    We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

  2. Are we there yet? Time to detection of nanohertz gravitational waves based on pulsar-timing array limits

    CERN Document Server

    Taylor, S R; Ellis, J A; Mingarelli, C M F; Lazio, T J W; van Haasteren, R

    2015-01-01

    Decade-long timing observations of arrays of millisecond pulsars have placed highly constraining upper limits on the amplitude of the nanohertz gravitational-wave stochastic signal from the mergers of supermassive black-hole binaries ($\\sim 10^{-15}$ strain at $f = 1/\\mathrm{yr}$). These limits suggest that binary merger rates have been overestimated, or that environmental influences from nuclear gas or stars accelerate orbital decay, reducing the gravitational-wave signal at the lowest, most sensitive frequencies. This prompts the question whether nanohertz gravitational waves are likely to be detected in the near future. In this letter, we answer this question quantitatively using simple statistical estimates, deriving the range of true signal amplitudes that are compatible with current upper limits, and computing expected detection probabilities as a function of observation time. We conclude that small arrays consisting of the pulsars with the least timing noise, which yield the tightest upper limits, have...

  3. Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes

    Directory of Open Access Journals (Sweden)

    Chuanjun Liu

    2017-02-01

    Full Text Available The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM sensor arrays based on molecularly imprinted sol-gel (MISG materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL; nonanal (NAL and bezaldehyde (BAL. The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS and tetrabutoxytitanium (TBOT. Aminopropyltriethoxysilane (APT; diethylaminopropyltrimethoxysilane (EAP and trimethoxy-phenylsilane (TMP were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA; nonanoic acid (NA and benzoic acid (BA were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA; multivariate analysis of covariance (MANCOVA and hierarchical cluster analysis (HCA. The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP effect and the matrix

  4. Highly specific detection of thrombin using an aptamer-based suspension array and the interaction analysis via microscale thermophoresis.

    Science.gov (United States)

    Liu, Yanan; Liu, Nan; Ma, Xinhua; Li, Xiaoli; Ma, Jia; Li, Ya; Zhou, Zhijiang; Gao, Zhixian

    2015-04-21

    A novel aptamer-based suspension array detection platform was designed for the sensitive, specific and rapid detection of human α-thrombin as a model. Thrombin was first recognized by a 29-mer biotinylated thrombin-binding aptamer (TBA) in solution. Then 15-mer TBA modified magnetic beads (MBs) captured the former TBA-thrombin to form an aptamer-thrombin-aptamer sandwich complex. The median fluorescence intensity obtained via suspension array technology was positively correlated with the thrombin concentration. The interactions between TBAs and thrombin were analyzed using microscale thermophoresis (MST). The dissociation constants could be respectively achieved to be 44.2 ± 1.36 nM (TBA1-thrombin) and 15.5 ± 0.637 nM (TBA2-thrombin), which demonstrated the high affinities of TBA-thrombin and greatly coincided with previous reports. Interaction conditions such as temperature, reaction time, and coupling protocol were optimized. The dynamic quantitative working range of the aptamer-based suspension array was 18.37-554.31 nM, and the coefficients of determination R(2) were greater than 0.9975. The lowest detection limit of thrombin was 5.4 nM. This method was highly specific for thrombin without being affected by other analogs and interfering proteins. The recoveries of thrombin spiked in diluted human serum were in the range 82.6-114.2%. This innovative aptamer-based suspension array detection platform not only exhibits good sensitivity based on MBs facilitating highly efficient separation and amplification, but also suggests high specificity by the selective aptamer binding, thereby suggesting the expansive application prospects in research and clinical fields.

  5. Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes

    Science.gov (United States)

    Liu, Chuanjun; Wyszynski, Bartosz; Yatabe, Rui; Hayashi, Kenshi; Toko, Kiyoshi

    2017-01-01

    The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix

  6. ARE WE THERE YET? TIME TO DETECTION OF NANOHERTZ GRAVITATIONAL WAVES BASED ON PULSAR-TIMING ARRAY LIMITS

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, S. R.; Vallisneri, M.; Ellis, J. A.; Mingarelli, C. M. F.; Lazio, T. J. W.; Haasteren, R. van, E-mail: Stephen.R.Taylor@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2016-03-01

    Decade-long timing observations of arrays of millisecond pulsars have placed highly constraining upper limits on the amplitude of the nanohertz gravitational-wave stochastic signal from the mergers of supermassive black hole binaries (∼10{sup −15} strain at f = 1 yr{sup −1}). These limits suggest that binary merger rates have been overestimated, or that environmental influences from nuclear gas or stars accelerate orbital decay, reducing the gravitational-wave signal at the lowest, most sensitive frequencies. This prompts the question whether nanohertz gravitational waves (GWs) are likely to be detected in the near future. In this Letter, we answer this question quantitatively using simple statistical estimates, deriving the range of true signal amplitudes that are compatible with current upper limits, and computing expected detection probabilities as a function of observation time. We conclude that small arrays consisting of the pulsars with the least timing noise, which yield the tightest upper limits, have discouraging prospects of making a detection in the next two decades. By contrast, we find large arrays are crucial to detection because the quadrupolar spatial correlations induced by GWs can be well sampled by many pulsar pairs. Indeed, timing programs that monitor a large and expanding set of pulsars have an ∼80% probability of detecting GWs within the next 10 years, under assumptions on merger rates and environmental influences ranging from optimistic to conservative. Even in the extreme case where 90% of binaries stall before merger and environmental coupling effects diminish low-frequency gravitational-wave power, detection is delayed by at most a few years.

  7. Clinical validation of integrated nucleic acid and protein detection on an electrochemical biosensor array for urinary tract infection diagnosis.

    Directory of Open Access Journals (Sweden)

    Ruchika Mohan

    Full Text Available BACKGROUND: Urinary tract infection (UTI is a common infection that poses a substantial healthcare burden, yet its definitive diagnosis can be challenging. There is a need for a rapid, sensitive and reliable analytical method that could allow early detection of UTI and reduce unnecessary antibiotics. Pathogen identification along with quantitative detection of lactoferrin, a measure of pyuria, may provide useful information towards the overall diagnosis of UTI. Here, we report an integrated biosensor platform capable of simultaneous pathogen identification and detection of urinary biomarker that could aid the effectiveness of the treatment and clinical management. METHODOLOGY/PRINCIPAL FINDINGS: The integrated pathogen 16S rRNA and host lactoferrin detection using the biosensor array was performed on 113 clinical urine samples collected from patients at risk for complicated UTI. For pathogen detection, the biosensor used sandwich hybridization of capture and detector oligonucleotides to the target analyte, bacterial 16S rRNA. For detection of the protein biomarker, the biosensor used an analogous electrochemical sandwich assay based on capture and detector antibodies. For this assay, a set of oligonucleotide probes optimized for hybridization at 37°C to facilitate integration with the immunoassay was developed. This probe set targeted common uropathogens including E. coli, P. mirabilis, P. aeruginosa and Enterococcus spp. as well as less common uropathogens including Serratia, Providencia, Morganella and Staphylococcus spp. The biosensor assay for pathogen detection had a specificity of 97% and a sensitivity of 89%. A significant correlation was found between LTF concentration measured by the biosensor and WBC and leukocyte esterase (p<0.001 for both. CONCLUSION/SIGNIFICANCE: We successfully demonstrate simultaneous detection of nucleic acid and host immune marker on a single biosensor array in clinical samples. This platform can be used for

  8. Investigation of a solvent-cast organogel to form a liquid-gel microinterface array for electrochemical detection of lysozyme.

    Science.gov (United States)

    Felisilda, Bren Mark B; Alvarez de Eulate, Eva; Arrigan, Damien W M

    2015-09-17

    Ion transfer at aqueous-organogel interfaces enables the non-redox detection of ions and ionisable species by voltammetry. In this study, a non-thermal method for preparation of an organogel was employed and used for the detection of hen-egg-white-lysozyme (HEWL) via adsorptive stripping voltammetry at an array of aqueous-organogel microinterfaces. Tetrahydrofuran solvent casting was employed to prepare the organogel mixture, hence removing the need for heating of the solution to be gelled, as used in previous studies. Cyclic voltammetry of HEWL at the microinterface array revealed a broad adsorption process on the forward scan, at positive applied potentials, followed by a desorption peak at ca. 0.68 V, indicating the detection of HEWL in this region. Application of an adsorption step, where a constant optimized potential of 0.95 V was applied, followed by voltammetric detection provided for a linear response range of 0.02-0.84 μM and a detection limit of 0.030 μM for 300 s adsorption. The detection limit was further improved by utilizing differential pulse stripping voltammetry, resulting in detection limits of 0.017 μM, 0.014 μM, and 0.010 μM for adsorptive pre-concentration times of 60, 120 and 300 s, respectively, in unstirred solutions. These results are an improvement over other methods for the detection of HEWL at aqueous-organic interfaces and offers a basis for the label-free detection of protein.

  9. Photoelectrochemical Immunosensor Array Based on Thioglycolic Acid Capped CdS Quantum Dots for Multiplexed Detection of Veterinary Drug Residues

    Institute of Scientific and Technical Information of China (English)

    肖飞; 赖彦君; 张苧丹; 白静; 鲜跃仲; 金利通

    2012-01-01

    A photoelectrochemical immunosensor based on multi-electrode array was developed for simultaneous and sen- sitive determination of veterinary drug residues. In this system, poly(dimethyldiallylammonium chloride) (PDDA), Au nanoparticles (Au NPs) and thioglycolic acid (TGA)-capped CdS quantum dots (QDs) were layer-by-layer as- sembled onto the home-made Au electrode array. The assembling process of the (CdS/PDDA/Au NPs/PDDA), mul- tilayer was characterized by electrochemical impedance spectroscopy. And then the antibodies for clenbuterol (CB), ractopamine (RAC) and chloramphenicol (CAP) were covalently immobilized onto the Au electrode array by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) coupling reaction, respectively. The concentrations of CB, RAC and CAP were measured based on the photoelectrochemical effects of CdS QDs. Under the optimal conditions the limits of detection (LOD) for CB, RAC and CAP were 25, 50 and 2.2 pg/mL (3a), respectively, with acceptable recovery over the range of 95.40%--105.5% in pig liver samples. All results indicate that the immunosensor array system has potential application for practical, effective and high throughput analysis of veterinary drugs residues.

  10. The Distributed Biological Observatory (DBO)-A Change Detection Array in the Pacific Arctic Sector

    Science.gov (United States)

    Grebmeier, J. M.; Moore, S. E.; Cooper, L. W.; Frey, K. E.; Pickart, R. S.

    2011-12-01

    latitudinal gradient. Hydrographic transects occupied from spring to fall in 2010 and 2011 at two pilot sites in the SE Chukchi Sea and Barrow Canyon provide repeat collections of water parameters over the seasons that are unavailable from single cruises. This sampling indicates freshening and warming as Pacific seawater transits northward over the spring to fall seasons, with impacts on both plankton and benthic prey bases for larger marine mammals and seabirds. The intent of the DBO is to serve as a change detection array for the identification and consistent monitoring of biophysical responses. This network of spatially explicit DBOs is being organized through the Pacific Arctic Group (PAG), a collaborative network endorsed by the International Arctic Science Committee. Our presentation will provide new information to evaluate the status and developing trends of the marine biological system as it responds to the rapid environmental change.

  11. Exploring Nanostructure Arrays for Single-Cell and Subcellular Manipulation and Detection

    DEFF Research Database (Denmark)

    Buch-Månson, Nina

    in adhesive contact as a cell settles into a NS array. Cellshave both been reported to deform completely into NS arrays or to stay suspended at the NS tipslike tiny fakirs, which have important implications for the possible applications. We show that,in addition to NS density, the energy difference between...... µm2 Here, we observe and define three distinct cell settling regimes (fully deformed, partly deformed, and fully suspended at the NC tips), where cells behave differently with respect to both cell morphology, detachment, mobility, actin structure and focal adhesion formation. Finally, we investigate......, in the continued study of cell behavior on polymeric NPs, cells are found to align with the NP pattern, but the degree of alignment is strongly dependent on NP array geometry and alignment is most efficient when cells adhere mainly to the NP tips. Therefore, we extend the cell settling prediction tool, which...

  12. Adhesive defect detection in composite adhesive joints using phased array transducers

    Science.gov (United States)

    Ren, Baiyang; Lissenden, Cliff J.

    2015-03-01

    Composite materials are widely used in aircraft structures due to their high specific stiffness and strength. The laminated nature of composite structures makes them subject to disbond and delamination. These types of defects will compromise the integrity of the structure and therefore need to be monitored. To monitor aircraft structures, light weight transducers capable of large area coverage are beneficial. Ultrasonic guided waves are able to travel long distance and are sensitive to localized defects. The multi-modal characteristic of propagating guided waves requires optimal mode selection and excitation. Phased array transducers provide good versatility for optimal mode excitation since they can excite different guided wave modes preferentially. Phased array transducers designed for structural health monitoring (SHM) applications are employed in this work to study the interaction between adhesive defects and guided wave modes. Amplitude ratios and wave packet composition are utilized as defect indicators that are uniquely available due to the phased array transducers.

  13. Microfluidic biosensor array with integrated poly(2,7-carbazole)/fullerene-based photodiodes for rapid multiplexed detection of pathogens.

    Science.gov (United States)

    Matos Pires, Nuno Miguel; Dong, Tao

    2013-11-25

    A multiplexed microfluidic biosensor made of poly(methylmethacrylate) (PMMA) was integrated into an array of organic blend heterojunction photodiodes (OPDs) for chemiluminescent detection of pathogens. Waterborne Escherichia coli O157:H7, Campylobacter jejuni and adenovirus were targeted in the PMMA chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene OPDs which showed a responsivity over 0.20 A/W at 425 nm. The limits of chemiluminescent detection were 5 × 10(5) cells/mL for E. coli, 1 × 10(5) cells/mL for C. jejuni, and 1 × 10(-8) mg/mL for adenovirus. Parallel analysis for all three analytes in less than 35 min was demonstrated. Further recovery tests illustrated the potential of the integrated biosensor for detecting bacteria in real water samples.

  14. Automated Flaw Detection Scheme For Cast Austenitic Stainless Steel Weld Specimens Using Hilbert Huang Transform Of Ultrasonic Phased Array Data

    Energy Technology Data Exchange (ETDEWEB)

    Khan, T.; Majumdar, Shantanu; Udpa, L.; Ramuhalli, Pradeep; Crawford, Susan L.; Diaz, Aaron A.; Anderson, Michael T.

    2012-01-01

    The objective of this work is to develop processing algorithms to detect and localize the flaws using NDE ultrasonic data. Data was collected using cast austenitic stainless steel (CASS) weld specimens on-loan from the U.S. nuclear power industry’s Pressurized Water Reactor Owners Group (PWROG) specimen set. Each specimen consists of a centrifugally cast stainless steel (CCSS) pipe section welded to a statically cast (SCSS) or wrought (WRSS) section. The paper presents a novel automated flaw detection and localization scheme using low frequency ultrasonic phased array inspection signals in the weld and heat affected zone of the base materials. The major steps of the overall scheme are preprocessing and region of interest (ROI) detection followed by the Hilbert Huang transform (HHT) of A-scans in the detected ROIs. HHT offers time-frequency-energy distribution for each ROI. The accumulation of energy in a particular frequency band is used as a classification feature for the particular ROI.

  15. Detection of near-surface and surface-breaking defects using ultrasonic arrays

    Science.gov (United States)

    Velichko, A.; Wilcox, P. D.; Drinkwater, B. W.

    2012-05-01

    An efficient Finite Element procedure for predicting the complete scattering behavior for an arbitrarily-shaped defect which is located near a free surface in an otherwise homogeneous isotropic half-space is presented. The data provided by this model is then used for simulating an ultrasonic array response for different near-surface and surface-breaking defects. Example results for 2D array (3D defects) are presented and compared with the experiment. Its practical application to the volumetric inspections of thin section is discussed.

  16. Detection of coffee flavour ageing by solid-phase microextraction/surface acoustic wave sensor array technique (SPME/SAW).

    Science.gov (United States)

    Barié, Nicole; Bücking, Mark; Stahl, Ullrich; Rapp, Michael

    2015-06-01

    The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising technique for highly sensitive and selective detection of volatile organic compounds (VOCs). We present new developments to achieve a low cost sensor setup with a sampling method enabling the highly reproducible detection of volatiles even in the ppb range. Since the VOCs of coffee are well known by gas chromatography (GC) research studies, the new sensor array was tested for an easy assessable objective: coffee ageing during storage. As reference method these changes were traced with a standard GC/FID set-up, accompanied by sensory panellists. The evaluation of GC data showed a non-linear characteristic for single compound concentrations as well as for total peak area values, disabling prediction of the coffee age. In contrast, the new SAW sensor array demonstrates a linear dependency, i.e. being capable to show a dependency between volatile concentration and storage time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    Science.gov (United States)

    Zhang, Hong-Ze; Zhang, Fang-Ting; Zhang, Xiao-Hui; Huang, Dong; Zhou, Ying-Lin; Li, Zhi-Hong; Zhang, Xin-Xiang

    2015-06-16

    Herein, we proposed a portable, easy-to-operate, and antifouling microcapsule array chip for target detection. This prepackaged chip was fabricated by innovative and cost-effective 3D ice printing integrating with photopolymerization sealing which could eliminate complicated preparation of wet chemistry and effectively resist outside contaminants. Only a small volume of sample (2 μL for each microcapsule) was consumed to fulfill the assay. All the reagents required for the analysis were stored in ice form within the microcapsule before use, which guaranteed the long-term stability of microcapsule array chips. Nitrite and glucose were chosen as models for proof of concept to achieve an instant quantitative detection by naked eyes without the need of external sophisticated instruments. The simplicity, low cost, and small sample consumption endowed ice-printing microcapsule array chips with potential commercial value in the fields of on-site environmental monitoring, medical diagnostics, and rapid high-throughput point-of-care quantitative assay.

  18. Detection of copy number variation from array intensity and sequencing read depth using a stepwise Bayesian model

    Directory of Open Access Journals (Sweden)

    Gerstein Mark B

    2010-10-01

    Full Text Available Abstract Background Copy number variants (CNVs have been demonstrated to occur at a high frequency and are now widely believed to make a significant contribution to the phenotypic variation in human populations. Array-based comparative genomic hybridization (array-CGH and newly developed read-depth approach through ultrahigh throughput genomic sequencing both provide rapid, robust, and comprehensive methods to identify CNVs on a whole-genome scale. Results We developed a Bayesian statistical analysis algorithm for the detection of CNVs from both types of genomic data. The algorithm can analyze such data obtained from PCR-based bacterial artificial chromosome arrays, high-density oligonucleotide arrays, and more recently developed high-throughput DNA sequencing. Treating parameters--e.g., the number of CNVs, the position of each CNV, and the data noise level--that define the underlying data generating process as random variables, our approach derives the posterior distribution of the genomic CNV structure given the observed data. Sampling from the posterior distribution using a Markov chain Monte Carlo method, we get not only best estimates for these unknown parameters but also Bayesian credible intervals for the estimates. We illustrate the characteristics of our algorithm by applying it to both synthetic and experimental data sets in comparison to other segmentation algorithms. Conclusions In particular, the synthetic data comparison shows that our method is more sensitive than other approaches at low false positive rates. Furthermore, given its Bayesian origin, our method can also be seen as a technique to refine CNVs identified by fast point-estimate methods and also as a framework to integrate array-CGH and sequencing data with other CNV-related biological knowledge, all through informative priors.

  19. No Radio Flaring Detected from Cygnus X-3 at 3 GHz by Allen Telescope Array

    Science.gov (United States)

    Williams, P. K. G.; Bower, G. C.; Tomsick, J. A.; Bodaghee, A.; Corbet, R. H. D.

    2011-01-01

    Following the announcement of a 98 GHz flare from the microquasar Cygnus X-3 (ATel #3130), we observed it with the Allen Telescope Array (Welch et al., 2009 Proc. IEEE 97 1438 for 2.5 hours beginning at 2011 January 28.848 UT (MJD 55589.848), about 4.0 hours after the 98 GHz observations concluded.

  20. Detection of Defective Sensors in Phased Array Using Compressed Sensing and Hybrid Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Shafqat Ullah Khan

    2016-01-01

    Full Text Available A compressed sensing based array diagnosis technique has been presented. This technique starts from collecting the measurements of the far-field pattern. The system linking the difference between the field measured using the healthy reference array and the field radiated by the array under test is solved using a genetic algorithm (GA, parallel coordinate descent (PCD algorithm, and then a hybridized GA with PCD algorithm. These algorithms are applied for fully and partially defective antenna arrays. The simulation results indicate that the proposed hybrid algorithm outperforms in terms of localization of element failure with a small number of measurements. In the proposed algorithm, the slow and early convergence of GA has been avoided by combining it with PCD algorithm. It has been shown that the hybrid GA-PCD algorithm provides an accurate diagnosis of fully and partially defective sensors as compared to GA or PCD alone. Different simulations have been provided to validate the performance of the designed algorithms in diversified scenarios.

  1. Report for Detection of Biothreat Agents and Environmental Samples using the LLNL Virulence Array for DHS

    Energy Technology Data Exchange (ETDEWEB)

    Jaing, Crystal [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gardner, Shea [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McLoughlin, Kevin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thissen, James [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jackson, Paul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-04-18

    The objective of this project is to provide DHS a comprehensive evaluation of the current genomic technologies including genotyping, Taqman PCR, multiple locus variable tandem repeat analysis (MLVA), microarray and high-throughput DNA sequencing in the analysis of biothreat agents from complex environmental samples. This report focuses on the design, testing and results of samples on the Virulence Array.

  2. Real-time calibration of the AARTFAAC array for transient detection

    NARCIS (Netherlands)

    Prasad, P.; Wijnholds, S.J.; Huizinga, F.; Wijers, R.A.M.J.

    2014-01-01

    The search for transient phenomena at low radio frequencies is now coming of age with the development of radio sky monitors with a large field of view, which are made feasible by new developments in calibration algorithms and computing. However, accurate calibration of such arrays is challenging, es

  3. Detecting single nucleotide polymorphisms using DNA arrays for plant pathogen diagnosis

    NARCIS (Netherlands)

    Lievens, B.; Claes, L.; Vanachter, A.C.R.C.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2006-01-01

    The lack of a rapid and reliable means for routine pathogen identification has been one of the main limitations in plant disease management, and has pushed the development of culture-independent, molecular approaches. Currently, DNA array technology is the most suitable technique for high-throughput

  4. Detection of Volatile Organic Compounds by Self-assembled Monolayer Coated Sensor Array with Concentration-independent Fingerprints

    Science.gov (United States)

    Chang, Ye; Tang, Ning; Qu, Hemi; Liu, Jing; Zhang, Daihua; Zhang, Hao; Pang, Wei; Duan, Xuexin

    2016-04-01

    In this paper, we have modeled and analyzed affinities and kinetics of volatile organic compounds (VOCs) adsorption (and desorption) on various surface chemical groups using multiple self-assembled monolayers (SAMs) functionalized film bulk acoustic resonator (FBAR) array. The high-frequency and micro-scale resonator provides improved sensitivity in the detections of VOCs at trace levels. With the study of affinities and kinetics, three concentration-independent intrinsic parameters (monolayer adsorption capacity, adsorption energy constant and desorption rate) of gas-surface interactions are obtained to contribute to a multi-parameter fingerprint library of VOC analytes. Effects of functional group’s properties on gas-surface interactions are also discussed. The proposed sensor array with concentration-independent fingerprint library shows potential as a portable electronic nose (e-nose) system for VOCs discrimination and gas-sensitive materials selections.

  5. Establishment and application of a multiplex genetic mutation-detection method of lung cancer based on MassARRAY platform

    Institute of Scientific and Technical Information of China (English)

    Hong-Xia Tian; Xu-Chao Zhang; Zhen Wang; Jian-Guang Chen; Shi-Liang Chen; Wei-Bang Guo; Yi-Long Wu

    2016-01-01

    Objective:This study aims to establish a method for highly parallel multiplexed detection of genetic mutations in Chinese lung cancer samples through Agena iPLEX chemistry and matrix-assisted laser desorption ionization time-of-flight analysis on MassARRAY mass spectrometry platform. Methods:We reviewed the related literature and data on lung cancer treatments. We also identified 99 mutation hot spots in 13 target genes closely related to the pathogenesis, drug resistance, and metastasis of lung cancer. A total of 297 primers, composed of 99 paired forward and reverse amplification primers and 99 matched extension primers, were designed using Assay Design software. The detection method was established by analyzing eight cell lines and six lung cancer specimens. The proposed method was then validated through comparisons by using a LungCartaTM kit. The sensitivity and specificity of the proposed method were evaluated by directly sequencingEGFR andKRAS genes in 100 lung cancer cases. Results:The proposed method was able to detect multiplex genetic mutations in lung cancer cell lines. This finding was consistent with the observations on previously reported mutations. The proposed method can also detect such mutations in clinical lung cancer specimens. This result was consistent with the observations with LungCartaTM kit. However, anFGFR2 mutation was detected only through the proposed method. The measured sensitivity and specificity were 100% and 96.3%, respectively. Conclusions:The proposed MassARRAY technology-based multiplex method can detect genetic mutations in Chinese lung cancer patients. Therefore, the proposed method can be applied to detect mutations in other cancer tissues.

  6. Development of a high-throughput resequencing array for the detection of pathogenic mutations in osteogenesis imperfecta.

    Directory of Open Access Journals (Sweden)

    Yao Wang

    Full Text Available Osteogenesis imperfecta (OI is a rare inherited skeletal disease, characterized by bone fragility and low bone density. The mutations in this disorder have been widely reported to be on various exonal hotspots of the candidate genes, including COL1A1, COL1A2, CRTAP, LEPRE1, and FKBP10, thus creating a great demand for precise genetic tests. However, large genome sizes make the process daunting and the analyses, inefficient and expensive. Therefore, we aimed at developing a fast, accurate, efficient, and cheaper sequencing platform for OI diagnosis; and to this end, use of an advanced array-based technique was proposed.A CustomSeq Affymetrix Resequencing Array was established for high-throughput sequencing of five genes simultaneously. Genomic DNA extraction from 13 OI patients and 85 normal controls and amplification using long-range PCR (LR-PCR were followed by DNA fragmentation and chip hybridization, according to standard Affymetrix protocols. Hybridization signals were determined using GeneChip Sequence Analysis Software (GSEQ. To examine the feasibility, the outcome from new resequencing approach was validated by conventional capillary sequencing method.Overall call rates using resequencing array was 96-98% and the agreement between microarray and capillary sequencing was 99.99%. 11 out of 13 OI patients with pathogenic mutations were successfully detected by the chip analysis without adjustment, and one mutation could also be identified using manual visual inspection.A high-throughput resequencing array was developed that detects the disease-associated mutations in OI, providing a potential tool to facilitate large-scale genetic screening for OI patients. Through this method, a novel mutation was also found.

  7. The electroanalytical detection of hydrazine: a comparison of the use of palladium nanoparticles supported on boron-doped diamond and palladium plated BDD microdisc array.

    Science.gov (United States)

    Batchelor-McAuley, Christopher; Banks, Craig E; Simm, Andrew O; Jones, Timothy G J; Compton, Richard G

    2006-01-01

    We show that both a random distribution of palladium nanoparticles supported on a BDD electrode or a palladium plated BDD microelectrode array can each provide a sensing platform for the electrocatalytic detection of hydrazine. The palladium nanoparticle modified electrode displays a sensitivity and limit of detection of 60 mA mol(-1) L and 2.6 microM respectively while the array has a sensitivity of 8 mA mol(-1) L with a detection limit of 1.8 microM. The beneficial cost implications of using palladium nano- or micro-particles in sensors compared to a palladium macroelectrode are evident. Interestingly the array of the nanoparticles shows similar sensitivity and limit of detection to the microelectrode array which probably indicates that the random distribution of the former leads to 'clumps' of nanoparticles that effectively act as microelectrodes.

  8. Exome sequencing and arrayCGH detection of gene sequence and copy number variation between ILS and ISS mouse strains.

    Science.gov (United States)

    Dumas, Laura; Dickens, C Michael; Anderson, Nathan; Davis, Jonathan; Bennett, Beth; Radcliffe, Richard A; Sikela, James M

    2014-06-01

    It has been well documented that genetic factors can influence predisposition to develop alcoholism. While the underlying genomic changes may be of several types, two of the most common and disease associated are copy number variations (CNVs) and sequence alterations of protein coding regions. The goal of this study was to identify CNVs and single-nucleotide polymorphisms that occur in gene coding regions that may play a role in influencing the risk of an individual developing alcoholism. Toward this end, two mouse strains were used that have been selectively bred based on their differential sensitivity to alcohol: the Inbred long sleep (ILS) and Inbred short sleep (ISS) mouse strains. Differences in initial response to alcohol have been linked to risk for alcoholism, and the ILS/ISS strains are used to investigate the genetics of initial sensitivity to alcohol. Array comparative genomic hybridization (arrayCGH) and exome sequencing were conducted to identify CNVs and gene coding sequence differences, respectively, between ILS and ISS mice. Mouse arrayCGH was performed using catalog Agilent 1 × 244 k mouse arrays. Subsequently, exome sequencing was carried out using an Illumina HiSeq 2000 instrument. ArrayCGH detected 74 CNVs that were strain-specific (38 ILS/36 ISS), including several ISS-specific deletions that contained genes implicated in brain function and neurotransmitter release. Among several interesting coding variations detected by exome sequencing was the gain of a premature stop codon in the alpha-amylase 2B (AMY2B) gene specifically in the ILS strain. In total, exome sequencing detected 2,597 and 1,768 strain-specific exonic gene variants in the ILS and ISS mice, respectively. This study represents the most comprehensive and detailed genomic comparison of ILS and ISS mouse strains to date. The two complementary genome-wide approaches identified strain-specific CNVs and gene coding sequence variations that should provide strong candidates to

  9. Robust myoelectric signal detection based on stochastic resonance using multiple-surface-electrode array made of carbon nanotube composite paper

    Science.gov (United States)

    Shirata, Kento; Inden, Yuki; Kasai, Seiya; Oya, Takahide; Hagiwara, Yosuke; Kaeriyama, Shunichi; Nakamura, Hideyuki

    2016-04-01

    We investigated the robust detection of surface electromyogram (EMG) signals based on the stochastic resonance (SR) phenomenon, in which the response to weak signals is optimized by adding noise, combined with multiple surface electrodes. Flexible carbon nanotube composite paper (CNT-cp) was applied to the surface electrode, which showed good performance that is comparable to that of conventional Ag/AgCl electrodes. The SR-based EMG signal system integrating an 8-Schmitt-trigger network and the multiple-CNT-cp-electrode array successfully detected weak EMG signals even when the subject’s body is in the motion, which was difficult to achieve using the conventional technique. The feasibility of the SR-based EMG detection technique was confirmed by demonstrating its applicability to robot hand control.

  10. Evaluation of the FilmArray® system for detection of Bacillus anthracis, Francisella tularensis, and Yersinia pestis

    Energy Technology Data Exchange (ETDEWEB)

    Seiner, Derrick R.; Colburn, Heather A.; Baird, Cheryl L.; Bartholomew, Rachel A.; Straub, Tim M.; Victry, Kristin D.; Hutchison, Janine R.; Valentine, Nancy B.; Bruckner-Lea, Cindy J.

    2013-04-29

    To evaluate the sensitivity and specificity of the Idaho Technologies FilmArray® Biothreat Panel for the detection of Bacillus anthracis (Ba), Francisella tularensis (Ft), and Yersinia pestis (Yp) DNA, and demonstrate the detection of Ba spores. Methods and Results: DNA samples from Ba, Ft and Yp strains and near-neighbors, and live Ba spores were analyzed using the Biothreat Panel, a multiplexed PCR-based assay for 17 pathogens and toxins. Sensitivity studies with DNA suggest a limit of detection of 250 genome equivalents (GEs) per sample. Furthermore, the correct call of Ft, Yp or Bacillus species was made in 63 of 72 samples tested at 25 GE or less. With samples containing 25 Ba Sterne spores, at least one of the two possible Ba markers were identified in all samples tested. We observed no cross-reactivity with near-neighbor DNAs.

  11. The use of waveform cross correlation at a three-component seismic array for detection, location, and magnitude estimation

    Science.gov (United States)

    Kitov, Ivan; Sanina, Irina

    2016-04-01

    Using the waveform cross-correlation technique, we have re-estimated relative locations and magnitudes of 200 events detected by an array consisting of seven 3-C sensors. All these events were quarry blasts conducted at several local/regional mines, which were detected and identified in the course of regional seismotectonic monitoring. From all detected signals we selected those having the highest quality and created a set of three-component templates for further cross correlation study. By changing the length of correlation window and the frequency band of the templates we selected optimal parameters for robust estimates of cross correlation coefficients and relative amplitudes/magnitudes of all signals. The relative locations and magnitude estimates obtained by cross correlation are compared to those in the catalog created in standard interactive analysis.

  12. Micro-flow Immunosensor Based on Thin-film Interdigitated Gold Array Microelectrodes for Cancer Biomarker Detection.

    Science.gov (United States)

    Ravalli, Andrea; Lozzi, Luca; Marrazza, Giovanna

    2016-01-01

    In this paper, we reported the development of a micro-flow label-free impedimetric biosensor based on the use of thin-film interdigitated gold array microelectrodes (IDA) for the detection of carbohydrate antigen 125 (CA125). The immunosensor is developed through the electropolymerization of anthranilic acid (AA) on the surface of IDA electrodes followed by the covalent attachment of anti-CA125 monoclonal antibody. CA125 protein affinity reaction was then evaluated by means of electrochemical impedance spectroscopy (EIS). The sensor was characterized by electrochemical techniques and scanning electron microscopy (SEM). Using the optimized experimental conditions, the developed immunosensor showed a good analytical performance for CA125 detection from 0 to 100 U/mL with estimated limit of detection (LOD = 3Sblank/Slope) of 7 U/mL.

  13. Accelerating object detection via a visual-feature-directed search cascade: algorithm and field programmable gate array implementation

    Science.gov (United States)

    Kyrkou, Christos; Theocharides, Theocharis

    2016-07-01

    Object detection is a major step in several computer vision applications and a requirement for most smart camera systems. Recent advances in hardware acceleration for real-time object detection feature extensive use of reconfigurable hardware [field programmable gate arrays (FPGAs)], and relevant research has produced quite fascinating results, in both the accuracy of the detection algorithms as well as the performance in terms of frames per second (fps) for use in embedded smart camera systems. Detecting objects in images, however, is a daunting task and often involves hardware-inefficient steps, both in terms of the datapath design and in terms of input/output and memory access patterns. We present how a visual-feature-directed search cascade composed of motion detection, depth computation, and edge detection, can have a significant impact in reducing the data that needs to be examined by the classification engine for the presence of an object of interest. Experimental results on a Spartan 6 FPGA platform for face detection indicate data search reduction of up to 95%, which results in the system being able to process up to 50 1024×768 pixels images per second with a significantly reduced number of false positives.

  14. Fast calibration methods using cosmic rays for a neutron detection array

    Institute of Scientific and Technical Information of China (English)

    YANG Zai-Hong; YE Yan-Lin; XIAO Jun; YOU Hai-Bo; LIU HONG-Na; SUN Ye-Lei; WANG Zi-Heng; CHEN Jie

    2012-01-01

    An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum,and to improve the position determination especially for positions close to the two ends of a long scintillation bar.An overall position resolution of about 3.0 cm (FWHM) was extracted from the residual analysis method and verified by a direct measurement.Energy calibration was also realized by selecting cosmic rays at different incident angles.The bulk light attenuation lengths for the four test bars were also determined.It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays.

  15. Detection of Trace Heavy Metals Ions by Arrays of Titania Nanotubes Annealed in Nitrogen

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhi-man; XIAO Peng; CAO Guo-zhong

    2009-01-01

    Redox response of trace heavy metals ions(THMIs) has better performance on highly ordered vertically oriented titania nanotube arrays(TNA) annealed in nitrogen. Experimental data showed that different THMIs possess different reaction peak shapes and charge and discharge capacities. Therefore, the TNA will become an important tool used for environmental protection and facilitating the rapid determination of THMIs. THMIs of 5×10~(-4) mol/L concentration were measured at a scan rate of 100 mV/s. The analytical utility of TNA is demonstrated in a neutral 0.5 mol/L Na_2SO_4 solution. The results sufficiently show that titania nanotube arrays electrodes(TNAE) will be used to measure THMIs.

  16. Detection of Staphylococcus epidermidis by a Quartz Crystal Microbalance Nucleic Acid Biosensor Array Using Au Nanoparticle Signal Amplification

    Directory of Open Access Journals (Sweden)

    Weiling Fu

    2008-10-01

    Full Text Available Staphylococcus epidermidis is a critical pathogen of nosocomial blood infections, resulting in significant morbidity and mortality. A piezoelectric quartz crystal microbalance (QCM nucleic acid biosensor array using Au nanoparticle signal amplification was developed to rapidly detect S. epidermidis in clinical samples. The synthesized thiolated probes specific targeting S. epidermidis 16S rRNA gene were immobilized on the surface of QCM nucleic acid biosensor arrays. Hybridization was induced by exposing the immobilized probes to the PCR amplified fragments of S. epidermidis, resulting in a mass change and a consequent frequency shift of the QCM biosensor. To further enhance frequency shift results from above described hybridizations, streptavidin coated Au nanoparticles were conjugated to the PCR amplified fragments. The results showed that the lowest detection limit of current QCM system was 1.3×103 CFU/mL. A linear correlation was found when the concentration of S. epidermidis varied from 1.3×103 to 1.3×107 CFU/mL. In addition, 55 clinical samples were detected with both current QCM biosensor system and conventional clinical microbiological method, and the sensitivity and specificity of current QCM biosensor system were 97.14% and 100%, respectively. In conclusion, the current QCM system is a rapid, low-cost and sensitive method that can be used to identify infection of S. epidermidis in clinical samples.

  17. Profiling and Quantitation of Bacterial Carotenoids by Liquid Chromatography and Photodiode Array Detection

    OpenAIRE

    1989-01-01

    An analytical method for the profiling and quantitative determination of carotenoids in bacteria is described. Exhaustive extraction of the pigments from four selected bacterial strains required treatment of the cells with potassium hydroxide or liquefied phenol or both before the addition of the extracting solvent (methanol or diethyl ether). The carotenoids in the extracts were separated by nonaqueous reversed-phase liquid chromatography in conjunction with photodiode array absorption detec...

  18. Detection of the Odor Signature of Ovarian Cancer using DNA-Decorated Carbon Nanotube Field Effect Transistor Arrays

    Science.gov (United States)

    Kehayias, Christopher; Kybert, Nicholas; Yodh, Jeremy; Johnson, A. T. Charlie

    Carbon nanotubes are low-dimensional materials that exhibit remarkable chemical and bio-sensing properties and have excellent compatibility with electronic systems. Here, we present a study that uses an electronic olfaction system based on a large array of DNA-carbon nanotube field effect transistors vapor sensors to analyze the VOCs of blood plasma samples collected from patients with malignant ovarian cancer, patients with benign ovarian lesions, and age-matched healthy subjects. Initial investigations involved coating each CNT sensor with single-stranded DNA of a particular base sequence. 10 distinct DNA oligomers were used to functionalize the carbon nanotube field effect transistors, providing a 10-dimensional sensor array output response. Upon performing a statistical analysis of the 10-dimensional sensor array responses, we showed that blood samples from patients with malignant cancer can be reliably differentiated from those of healthy control subjects with a p-value of 3 x 10-5. The results provide preliminary evidence that the blood of ovarian cancer patients contains a discernable volatile chemical signature that can be detected using DNA-CNT nanoelectronic vapor sensors, a first step towards a minimally invasive electronic diagnostic technology for ovarian cancer.

  19. Denaturation strategies for detection of double stranded PCR products on GMR magnetic biosensor array

    DEFF Research Database (Denmark)

    Rizzi, Giovanni; Lee, Jung-Rok; Guldberg, Per

    2017-01-01

    Microarrays and other surface-based nucleic acid detection schemes rely on the hybridization of the target to surface-bound detection probes. We present the first comparison of two strategies to detect DNA using a giant magnetoresistive (GMR) biosensor platform starting from an initially double...

  20. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    López Terrones, Marcos Alonso, E-mail: malt.marcos@gmail.com [Ingeniería Biomédica, Dirección de Planeación, Servicios de Salud de Durango. Cuauhtémoc 225 Norte, Durango, Durango 34000 (Mexico); Solís-Nájera, Sergio Enrique, E-mail: solisnajera@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, México, DF 04510 (Mexico)

    2014-11-07

    Nowadays, magnetic resonance (MR) in Mexico has become a standard technique for clinical imaging. Although most of the times the MR systems contain only coils oriented for adults. Radiologists use these coils for children studies due to the non-availability of pediatric coils. Image quality is decreased due to the low signal to noise ratio delivered to the system. The development of RF coils is always focused towards increasing SNR and optimizing the RF penetration into the sample. Moreover, spinal pathologies in children, which are an important topic in pediatric care, cover congenital and neuromuscular disorders that occur in childhood. In this work, the design of a dedicated six-channel coil for detection of spinal pathologies at 1.5 Tesla is addressed. Numerical electromagnetic simulations were performed in order to evaluate their magnetic field performance at (63.6 MHz) 1.5 Tesla. The magnetic field uniformity as well as the RF penetration depth of the coil configurations was evaluated in order to find the best/optimized coil array configuration. The coil is comprised of three rows, one with 4 coil elements and two with only one coil element. Phantom and in vivo images were acquired with the six-channel pediatric coil array. The phantom images agree with the simulated data. In vivo images acquired with the 6-channel pediatric coil array have shown very good penetration depth and homogeneity, which allow better image quality throughout the whole FOV. In addition, the parallel imaging capabilities of the array allow the acceleration of the experiments avoiding possible motion artifacts.

  1. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    Science.gov (United States)

    López Terrones, Marcos Alonso; Solís-Nájera, Sergio Enrique

    2014-11-01

    Nowadays, magnetic resonance (MR) in Mexico has become a standard technique for clinical imaging. Although most of the times the MR systems contain only coils oriented for adults. Radiologists use these coils for children studies due to the non-availability of pediatric coils. Image quality is decreased due to the low signal to noise ratio delivered to the system. The development of RF coils is always focused towards increasing SNR and optimizing the RF penetration into the sample. Moreover, spinal pathologies in children, which are an important topic in pediatric care, cover congenital and neuromuscular disorders that occur in childhood. In this work, the design of a dedicated six-channel coil for detection of spinal pathologies at 1.5 Tesla is addressed. Numerical electromagnetic simulations were performed in order to evaluate their magnetic field performance at (63.6 MHz) 1.5 Tesla. The magnetic field uniformity as well as the RF penetration depth of the coil configurations was evaluated in order to find the best/optimized coil array configuration. The coil is comprised of three rows, one with 4 coil elements and two with only one coil element. Phantom and in vivo images were acquired with the six-channel pediatric coil array. The phantom images agree with the simulated data. In vivo images acquired with the 6-channel pediatric coil array have shown very good penetration depth and homogeneity, which allow better image quality throughout the whole FOV. In addition, the parallel imaging capabilities of the array allow the acceleration of the experiments avoiding possible motion artifacts.

  2. 涡流阵列检测技术%Detecting technology of eddy current array

    Institute of Scientific and Technical Information of China (English)

    徐可北

    2004-01-01

      涡流阵列(Eddy Current Arrays)技术是近10年内出现的一项新的涡流检测技术,它是通过涡流检测线圈结构的特殊设计,并借助于计算化的涡流仪强大的分析、计算及处理功能,实现对材料和零件的快速、有效地检测.……

  3. A fast and accurate method to detect allelic genomic imbalances underlying mosaic rearrangements using SNP array data

    Directory of Open Access Journals (Sweden)

    Pique-Regi Roger

    2011-05-01

    Full Text Available Abstract Background Mosaicism for copy number and copy neutral chromosomal rearrangements has been recently identified as a relatively common source of genetic variation in the normal population. However its prevalence is poorly defined since it has been only studied systematically in one large-scale study and by using non optimal ad-hoc SNP array data analysis tools, uncovering rather large alterations (> 1 Mb and affecting a high proportion of cells. Here we propose a novel methodology, Mosaic Alteration Detection-MAD, by providing a software tool that is effective for capturing previously described alterations as wells as new variants that are smaller in size and/or affecting a low percentage of cells. Results The developed method identified all previously known mosaic abnormalities reported in SNP array data obtained from controls, bladder cancer and HapMap individuals. In addition MAD tool was able to detect new mosaic variants not reported before that were smaller in size and with lower percentage of cells affected. The performance of the tool was analysed by studying simulated data for different scenarios. Our method showed high sensitivity and specificity for all assessed scenarios. Conclusions The tool presented here has the ability to identify mosaic abnormalities with high sensitivity and specificity. Our results confirm the lack of sensitivity of former methods by identifying new mosaic variants not reported in previously utilised datasets. Our work suggests that the prevalence of mosaic alterations could be higher than initially thought. The use of appropriate SNP array data analysis methods would help in defining the human genome mosaic map.

  4. 64-pixel NbTiN superconducting nanowire single-photon detector array for spatially resolved photon detection

    CERN Document Server

    Miki, Shigehito; Wang, Zhen; Terai, Hirotaka

    2014-01-01

    We present the characterization of two-dimensionally arranged 64-pixel NbTiN superconducting nanowire single-photon detector array for spatially resolved photon detection. NbTiN films deposited on thermally oxidized Si substrates enabled the high-yield production of high-quality SSPD pixels, and all 64 SSPD pixels showed uniform superconducting characteristics. Furthermore, all of the pixels showed single-photon sensitivity, and 60 of the 64 pixels showed a pulse generation probability higher than 90% after photon absorption. As a result of light irradiation from the single-mode optical fiber at different distances between the fiber tip and the active area, the variations of system detection efficiency in each pixel showed reasonable Gaussian distribution to represent the spatial distributions of photon flux intensity.

  5. Feasibility of VHE gamma ray detection by an array of imaging atmospheric Cherenkov telescopes using the fluorescence technique

    CERN Document Server

    Contreras, J L; Arqueros, F; López, M; Barrio, J A; Nievas, M

    2015-01-01

    The last 20 years have seen the development of new techniques in Astroparticle Physics providing access to the highest end of the electromagnetic spectrum. It has been shown that some sources emit photons up to energies close to 100 TeV. Yet the fluxes of these photons are incredibly low and new detection techniques are needed to go higher in energy. A new technique that would use the new generation of Cherenkov Telescopes, i.e., the Cherenkov Telescope Array (CTA), is proposed to push further the energy frontier. It is based on the detection of the fluorescence radiation emitted in extensive air showers, a successful method used in ultra-high-energy cosmic ray experiments, like the Pierre Auger Observatory. It would complement the standard imaging atmospheric Cherenkov technique with only minor modifications of the hardware currently being developed for the CTA and would not imply significant extra costs during its planned operation.

  6. Gas sensitivity and sensing mechanism studies on Au-doped TiO₂ nanotube arrays for detecting SF₆ decomposed components.

    Science.gov (United States)

    Zhang, Xiaoxing; Yu, Lei; Tie, Jing; Dong, Xingchen

    2014-10-17

    The analysis to SF6 decomposed component gases is an efficient diagnostic approach to detect the partial discharge in gas-insulated switchgear (GIS) for the purpose of accessing the operating state of power equipment. This paper applied the Au-doped TiO2 nanotube array sensor (Au-TiO2 NTAs) to detect SF6 decomposed components. The electrochemical constant potential method was adopted in the Au-TiO2 NTAs' fabrication, and a series of experiments were conducted to test the characteristic SF6 decomposed gases for a thorough investigation of sensing performances. The sensing characteristic curves of intrinsic and Au-doped TiO2 NTAs were compared to study the mechanism of the gas sensing response. The results indicated that the doped Au could change the TiO2 nanotube arrays' performances of gas sensing selectivity in SF6 decomposed components, as well as reducing the working temperature of TiO2 NTAs.

  7. Gun muzzle flash detection using a single photon avalanche diode array in 0.18µm CMOS technology

    Science.gov (United States)

    Savuskan, Vitali; Jakobson, Claudio; Merhav, Tomer; Shoham, Avi; Brouk, Igor; Nemirovsky, Yael

    2015-05-01

    In this study, a CMOS Single Photon Avalanche Diode (SPAD) 2D array is used to record and sample muzzle flash events in the visible spectrum, from representative weapons. SPADs detect the emission peaks of alkali salts, potassium or sodium, with spectral emission lines around 769nm and 589nm, respectively. The alkali salts are included in the gunpowder to suppress secondary flashes ignited during the muzzle flash event. The SPADs possess two crucial properties for muzzle flash imaging: (i) very high photon detection sensitivity, (ii) a unique ability to convert the optical signal to a digital signal at the source pixel, thus practically eliminating readout noise. The sole noise sources are the ones prior to the readout circuitry (optical signal distribution, avalanche initiation distribution and nonphotonic generation). This enables high sampling frequencies in the kilohertz range without significant SNR degradation, in contrast to regular CMOS image sensors. This research will demonstrate the SPAD's ability to accurately sample and reconstruct the temporal behavior of the muzzle flash in the visible wavelength, in the presence of sunlight. The reconstructed signal is clearly distinguishable from background clutter, through exploitation of flash temporal characteristics and signal processing, which will be reported. The frame rate of ~16 KHz was chosen as an optimum between SNR degradation and temporal profile recognition accuracy. In contrast to a single SPAD, the 2D array allows for multiple events to be processed simultaneously. Moreover, a significant field of view is covered, enabling comprehensive surveillance and imaging.

  8. On the detection and tracking of space debris using the Murchison Widefield Array. I. Simulations and test observations demonstrate feasibility

    CERN Document Server

    Tingay, S J; McKinley, B; Briggs, F; Wayth, R B; Hurley-Walker, N; Kennewell, J; Smith, C; Zhang, K; Arcus, W; Bhat, R; Emrich, D; Herne, D; Kudryavtseva, N; Lynch, M; Ord, S M; Waterson, M; Barnes, D G; Bell, M; Gaensler, B M; Lenc, E; Bernardi, G; Greenhill, L J; Kasper, J C; Bowman, J D; Jacobs, D; Bunton, J D; deSouza, L; Koenig, R; Pathikulangara, J; Stevens, J; Cappallo, R J; Corey, B E; Kincaid, B B; Kratzenberg, E; Lonsdale, C J; McWhirter, S R; Rogers, A E E; Salah, J E; Whitney, A R; Deshpande, A; Prabu, T; Shankar, N Udaya; Srivani, K S; Subrahmanyan, R; Ewall-Wice, A; Feng, L; Goeke, R; Morgan, E; Remillard, R A; Williams, C L; Hazelton, B J; Morales, M F; Johnston-Hollitt, M; Mitchell, D A; Procopio, P; Riding, J; Webster, R L; Wyithe, J S B; Oberoi, D; Roshi, A; Sault, R J; Williams, A

    2013-01-01

    The Murchison Widefield Array (MWA) is a new low frequency interferomeric radio telescope. The MWA is the low frequency precursor to the Square Kilometre Array (SKA) and is the first of three SKA precursors to be operational, supporting a varied science mission ranging from the attempted detection of the Epoch of Reionisation to the monitoring of solar flares and space weather. We explore the possibility that the MWA can be used for the purposes of Space Situational Awareness (SSA). In particular we propose that the MWA can be used as an element of a passive radar facility operating in the frequency range 87.5 - 108 MHz (the commercial FM broadcast band). In this scenario the MWA can be considered the receiving element in a bi-static radar configuration, with FM broadcast stations serving as non-cooperative transmitters. The FM broadcasts propagate into space, are reflected off debris in Earth orbit, and are received at the MWA. The imaging capabilities of the MWA can be used to simultaneously detect multiple...

  9. Design of a portable noninvasive photoacoustic glucose monitoring system integrated laser diode excitation with annular array detection

    Science.gov (United States)

    Zeng, Lvming; Liu, Guodong; Yang, Diwu; Ren, Zhong; Huang, Zhen

    2008-12-01

    A near-infrared photoacoustic glucose monitoring system, which is integrated dual-wavelength pulsed laser diode excitation with eight-element planar annular array detection technique, is designed and fabricated during this study. It has the characteristics of nonivasive, inexpensive, portable, accurate location, and high signal-to-noise ratio. In the system, the exciting source is based on two laser diodes with wavelengths of 905 nm and 1550 nm, respectively, with optical pulse energy of 20 μJ and 6 μJ. The laser beam is optically focused and jointly projected to a confocal point with a diameter of 0.7 mm approximately. A 7.5 MHz 8-element annular array transducer with a hollow structure is machined to capture photoacoustic signal in backward mode. The captured signals excitated from blood glucose are processed with a synthetic focusing algorithm to obtain high signal-to-noise ratio and accurate location over a range of axial detection depth. The custom-made transducer with equal area elements is coaxially collimated with the laser source to improve the photoacoustic excite/receive efficiency. In the paper, we introduce the photoacoustic theory, receive/process technique, and design method of the portable noninvasive photoacoustic glucose monitoring system, which can potentially be developed as a powerful diagnosis and treatment tool for diabetes mellitus.

  10. Ultrasensitive nanostructure sensor arrays on flexible substrates for multiplexed and simultaneous electrochemical detection of a panel of cardiac biomarkers.

    Science.gov (United States)

    Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Chaudhry, Shajee; Anguiano, Jonathan; Prasad, Shalini

    2017-03-15

    Multiplexed detection of protein biomarkers offers new opportunities for early diagnosis and efficient treatment of complex diseases. Cardiovascular diseases (CVDs) has the highest mortality risk in USA and Europe with 15-20 million cases being reported annually. Cardiac Troponins (T and I) are well established protein biomarkers associated with heart muscle damage and point-of-care monitoring of both these two biomarkers has significant benefits on patient care. A flexible disposable electrochemical biosensor device comprising of vertically oriented zinc oxide (ZnO) nanostructures was developed for rapid and simultaneous screening of cardiac Troponin-I (cTnI) and cardiac-Troponin-T (cTnT) in a point-of-care sensor format. The biosensors were designed by selective hydrothermal growth of ZnO nanostructures onto the working electrodes of polyimide printed circuit board platforms, resulting in the generation of high density nanostructure ZnO arrays based electrodes. The size, density and surface terminations of the nanostructures were leveraged towards achieving surface confinement of the target cTnT and cTnI molecules on to the electrode surface. Multiplexing and simultaneous detection was achieved through sensor platform design comprising of arrays of Troponin functionalized ZnO nanostructure electrodes. The sensitivity and specificity of the biosensor was characterized using two types of electrochemical techniques; electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis on the same sensor platform to demonstrate multi-configurable modes. Limit of detection of 1pg/mL in human serum was achieved for both cTnI and cTnT. Cross reactivity analysis showed the selectivity of detecting cTnT and cTnI in human serum with wide dynamic range.

  11. Implications of Sea Ice on Southern Ocean Microseisms Detected by a Seismic Array in West Antarctica

    Science.gov (United States)

    Pratt, Martin J.; Wiens, Douglas A.; Winberry, J. Paul; Anandakrishnan, Sridhar; Euler, Garrett G.

    2017-01-01

    SUMMARYThe proximity of Southern Ocean storms coupled with seasonal variation in sea ice make Antarctica ideal for the study of microseism sources. We explore frequency-dependent beamforming results using a short-duration, 60 km aperture, broadband seismic array located on the Whillans Ice Stream, West Antarctica. Locations of single-frequency microseism (13-16 s period) generation are in regions where the continental shelf is ice-free, consistent with previous studies, and show Rayleigh wave sources remaining at consistent back azimuths throughout the duration of the array. Beamforming analysis of daily noise correlations shows that long-period double-frequency microseisms (9-11 s) consist predominantly of Rayleigh waves excited by storms in the Southern Ocean. Modelling of source locations based on wave-wave interaction provides a good fit to our data at these periods. We show that short-period double-frequency microseisms (5-7 s) in Antarctica consist of crustal phase Lg and body waves. Lg arrivals propagate through regions of continental crust and our data show that the Lg energy is generated when storm systems interact with the sea ice-free continental shelf during austral summers. Ultra-short-period (0.3-2 s) microseismic body waves back project to regions that correlate with oceanic storm systems in both the Southern and Northern Hemispheres.

  12. A Supramolecular Sensor Array Using Lanthanide-Doped Nanoparticles for Sensitive Detection of Glyphosate and Proteins.

    Science.gov (United States)

    Wang, Meng; Ye, Hebo; You, Lei; Chen, Xueyuan

    2016-01-13

    Lanthanide (Ln(3+))-doped nanoparticles (NPs) are an intensive area of research in chemical and materials sciences. Herein a sensor array of Ln(3+)-doped NPs was developed for the first time toward sensitive molecular sensing based on a novel strategy of the hybridized time-resolved Förster resonance energy transfer (TR-FRET) with the indicator displacement assay (IDA) concept (TR-FRET-IDA). The sensor platform was generated in situ by binding a series of negatively charged indicators on the surface of ligand-free LiYF4:Ce/Tb NPs. The TR-FRET between NPs and dyes resulted in indicator emission and was employed as a means of removing undesired short-lived background luminescence from the indicator effectively. Displacement of indicators from the NP/indicator ensembles by glyphosate, a common herbicide, led to turn-off of the indicator emission. The sensor array was able to successfully discriminate 11 biologically relevant anions with high accuracy and sensitivity in pure aqueous buffer both qualitatively and quantitatively. Furthermore, the differentiation of six model proteins in the nM range was achieved with 100% accuracy for the classification, thereby demonstrating the versatility of this simple sensor platform. The study of the mechanism of binding and signal modulation further verified TR-FRET-IDA as a reliable sensing paradigm.

  13. Detection of Mycoplasma pneumoniae in simulated and true clinical throat swab specimens by nanorod array-surface-enhanced Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Suzanne L Hennigan

    Full Text Available The prokaryote Mycoplasma pneumoniae is a major cause of respiratory disease in humans, accounting for 20% of all community-acquired pneumonia and the leading cause of pneumonia in older children and young adults. The limitations of existing options for mycoplasma diagnosis highlight a critical need for a new detection platform with high sensitivity, specificity, and expediency. Here we evaluated silver nanorod arrays (NA as a biosensing platform for detection and differentiation of M. pneumoniae in culture and in spiked and true clinical throat swab samples by surface-enhanced Raman spectroscopy (SERS. Three M. pneumoniae strains were reproducibly differentiated by NA-SERS with 95%-100% specificity and 94-100% sensitivity, and with a lower detection limit exceeding standard PCR. Analysis of throat swab samples spiked with M. pneumoniae yielded detection in a complex, clinically relevant background with >90% accuracy and high sensitivity. In addition, NA-SERS correctly classified with >97% accuracy, ten true clinical throat swab samples previously established by real-time PCR and culture to be positive or negative for M. pneumoniae. Our findings suggest that the unique biochemical specificity of Raman spectroscopy, combined with reproducible spectral enhancement by silver NA, holds great promise as a superior platform for rapid and sensitive detection and identification of M. pneumoniae, with potential for point-of-care application.

  14. Simultaneous detection of 13 viruses involved in meningoencephalitis using a newly developed multiplex PCR Mag-array system.

    Science.gov (United States)

    Shi, Xiaodan; Wu, Rui; Shi, Ming; Zhou, Linfu; Wu, Mengli; Yang, Yining; An, Xinyue; Dai, Wen; Tian, Liang; Zhang, Chen; Ma, Xuejun; Zhao, Gang

    2016-08-01

    The early detection and identification of pathogens in central nervous system viral infections associated with neurological disease increases the survival rate. However, the limitations of current diagnostic methods contribute to a lack of proper diagnosis in 62% of patients. Therefore, a robust method for detecting multiple viruses in a single reaction with high specificity, throughput, and speed is required. A multiplex PCR Mag-Array (MPMA) system was developed that integrates three strategies: chimeric primer design, temperature switch PCR, and MagPlex-TAG techniques. The MPMA was used to amplify 13 target viral sequences simultaneously, with plasmids containing specific viral sequences as standard samples. To evaluate its clinical performance, 177 cerebrospinal fluid (CSF) samples were tested. The MPMA system presented high specificity and efficiency in detecting a control panel of 13 plasmids. Among 177 CSF samples, consistent results were achieved for 19 samples pre-tested using a commercial kit. Viral pathogens were found in 28/138 undiagnosed samples, with herpes simplex viruses (HSV-1 and HSV-2) being predominant. The 20 non-infectious samples revealed negative results. Compared to sequencing methods, sensitivity for detecting HSV-1 and HSV-2 was 100% and 98.78%, respectively, and specificity was 100% and 98.22%, respectively. A robust MPMA system that can simultaneously and reliably detect 13 meningoencephalitis-associated viruses with high specificity, throughput, and speed has been developed. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Prospects for the detection of high-energy (E > 25 GeV) Fermi pulsars with the Cherenkov Telescope Array

    Science.gov (United States)

    Burtovoi, A.; Saito, T. Y.; Zampieri, L.; Hassan, T.

    2017-10-01

    Around 160 gamma-ray pulsars were discovered by the Fermi-Large Area Telescope (LAT) since 2008. The most energetic of them, 12 objects with emission above 25 GeV, are suitable candidates for the detection with the current and future Imaging Atmospheric Cherenkov Telescopes above few tens of GeV. We perform an analysis of the Fermi-LAT data of these high-energy pulsars in order to determine if such objects can be detected with the Cherenkov Telescope Array (CTA). Our goal is to forecast the significance of their point source detection with CTA. We analyse 5 yr of the Fermi-LAT data fitting the spectra of each pulsar at energies E > 10 GeV with a power-law function. Assuming no spectral cut-off, we extrapolate the resulting spectra to the very high energy range (VHE, E > 0.1 TeV) and simulate CTA observations of all 12 pulsars with the ctools software package. Using different analysis tools, individual CTA sensitivity curves are independently calculated for each pulsar and cross-checked with the ctools results. Our simulations result in significant CTA detections of up to eight pulsars in 50 h. Observations of the most energetic Fermi pulsars with CTA will shed light on the nature of the high-energy emission of pulsars, clarifying whether the VHE emission detected in the Crab pulsar spectrum is present also in other gamma-ray pulsars.

  16. Femtomolar Detection of Silver Nanoparticles by Flow-Enhanced Direct-Impact Voltammetry at a Microelectrode Array.

    Science.gov (United States)

    Sokolov, Stanislav V; Bartlett, Thomas R; Fair, Peter; Fletcher, Stephen; Compton, Richard G

    2016-09-06

    We report the femtomolar detection of silver (Ag) nanoparticles by direct-impact voltammetry. This is achieved through the use of a random array of microelectrodes (RAM) integrated into a purpose-built flow cell, allowing combined diffusion and convection to the electrode surface. A coupled RAM-flow cell system is implemented and is shown to give reproducible wall-jet type flow characteristics, using potassium ferrocyanide as a molecular redox species. The calibrated flow system is then used to detect and quantitatively size Ag nanoparticles at femtomolar concentrations. Under flow conditions, it is found the nanoparticle impact frequency increases linearly with the volumetric flow rate. The resulting limit of detection is more than 2 orders of magnitude smaller than the previous detection limit for direct-impact voltammetry (900 fM) [J. Ellison et al. Sens. Actuators, B 2014, 200, 47], and is more than 30 times smaller than the previous detection limit for mediated-impact voltammetry (83 fM) [T. M. Alligrant et al. Langmuir 2014, 30, 13462].

  17. Maximum detection range limitation of pulse laser radar with Geiger-mode avalanche photodiode array

    Science.gov (United States)

    Luo, Hanjun; Xu, Benlian; Xu, Huigang; Chen, Jingbo; Fu, Yadan

    2015-05-01

    When designing and evaluating the performance of laser radar system, maximum detection range achievable is an essential parameter. The purpose of this paper is to propose a theoretical model of maximum detection range for simulating the Geiger-mode laser radar's ranging performance. Based on the laser radar equation and the requirement of the minimum acceptable detection probability, and assuming the primary electrons triggered by the echo photons obey Poisson statistics, the maximum range theoretical model is established. By using the system design parameters, the influence of five main factors, namely emitted pulse energy, noise, echo position, atmospheric attenuation coefficient, and target reflectivity on the maximum detection range are investigated. The results show that stronger emitted pulse energy, lower noise level, more front echo position in the range gate, higher atmospheric attenuation coefficient, and higher target reflectivity can result in greater maximum detection range. It is also shown that it's important to select the minimum acceptable detection probability, which is equivalent to the system signal-to-noise ratio for producing greater maximum detection range and lower false-alarm probability.

  18. Detection of Prostate Specific Membrane Antigen at Picomolar Levels Using Biocatalysis Coupled to Assisted Ion Transfer Voltammetry at a Liquid-Organogel Microinterface Array.

    Science.gov (United States)

    Akter, Rashida; Arrigan, Damien W M

    2016-12-06

    A label-free electrochemical strategy for the detection of a cancer biomarker, prostate specific membrane antigen (PSMA), at picomolar concentrations without the use of antibodies, was investigated. The approach is based on the assisted ion transfer of protons, generated by a series of enzymatic reactions, at an array of microinterfaces between two immiscible electrolyte solutions (μ-ITIES). This nonredox electrochemical approach based on biocatalysis-coupled proton transfer at the μ-ITIES array opens a new way to detect the prostate cancer biomarker, with detection capability achieved at concentrations below those indicative of disease presence. The strategy is expected to contribute to cancer diagnostics, recurrence monitoring, and therapeutic treatment efficacy.

  19. A Microcantilever Sensor Array for the Detection and Inventory of Desert Tortoises

    Energy Technology Data Exchange (ETDEWEB)

    Venedam, R. J.; Dillingham, T. R.

    2008-07-01

    We have designed and tested a portable instrument consisting of a small infrared camera coupled with an array of piezoresistive microcantilever sensors that is used to provide real-time, non-invasive data on desert tortoise den occupancy. The piezoresistive microcantilever (PMC) sensors are used to obtain a chemical “signature” of tortoise presence from the air deep within the dens, and provide data in cases where the camera cannot extend deep enough into the den to provide visual evidence of tortoise presence. The infrared camera was used to verify the PMC data during testing, and in many cases, such as shallower dens, may be used to provide exact numbers on den populations.

  20. Synthesis of Fe Doped ZnO Nanowire Arrays that Detect Formaldehyde Gas.

    Science.gov (United States)

    Jeon, Yoo Sang; Seo, Hyo Won; Kim, Su Hyo; Kim, Young Keun

    2016-05-01

    Owing to their chemical and thermal stability and doping effects on providing electrons to the conduction band, doped ZnO nanowires have generated interest for use in electronic devices. Here we report hydrothermally grown Fe-doped ZnO nanowires and their gas-sensing properties. The synthesized nanowires have a high crystallinity and are 60 nm in diameter and 1.7 μm in length. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are employed to understand the doping effects on the microstructures and gas sensing properties. When the Fe-doped ZnO nanowire arrays were evaluated for gas sensing, responses were recorded through changes in temperature and gas concentration. Gas sensors consisting of ZnO nanowires doped with 3-5 at.% Fe showed optimum formaldehyde (HCHO) sensing performance at each working temperature.

  1. A 256-TES Array for the Detection of CMB B-Mode Polarisation

    Science.gov (United States)

    Perbost, C.; Marnieros, S.; Bélier, B.; Piat, M.; Prêle, D.; Voisin, F.; Decourcelle, T.

    2016-08-01

    As part of the Q&U Bolometric Interferometer for Cosmology instrument targeting the cosmic microwave background primordial B-modes, two kilo-pixel focal planes have been designed for a NEP of ˜ 3 × 10^{-17} W√{Hz} adapted for ground-based observations. Those pixels are transition edge sensors (TESs) made of voltage-biased NbSi thin films with a critical temperature T_c ˜ 400 mK and TiV absorbing grids. The TESs are coupled to a time-domain multiplexed electronics based on superconducting quantum interference devices and an additional SiGe cryogenic integrated circuit which provides a second multiplexing stage. In this paper, we briefly discuss the instrumental context of a quarter of focal plane (a 256-TES sub-array). Then, we present its typical manufacturing process and first test results at cryogenic temperature.

  2. High-resolution parallel-detection sensor array using piezo-phototronics effect

    Science.gov (United States)

    Wang, Zhong L.; Pan, Caofeng

    2015-07-28

    A pressure sensor element includes a substrate, a first type of semiconductor material layer and an array of elongated light-emitting piezoelectric nanostructures extending upwardly from the first type of semiconductor material layer. A p-n junction is formed between each nanostructure and the first type semiconductor layer. An insulative resilient medium layer is infused around each of the elongated light-emitting piezoelectric nanostructures. A transparent planar electrode, disposed on the resilient medium layer, is electrically coupled to the top of each nanostructure. A voltage source is coupled to the first type of semiconductor material layer and the transparent planar electrode and applies a biasing voltage across each of the nanostructures. Each nanostructure emits light in an intensity that is proportional to an amount of compressive strain applied thereto.

  3. The Trace Analysis of DEET in Water using an On-line Preconcentration Column and Liquid Chromatography with UV Photodiode Array Detection

    Science.gov (United States)

    A method for the detection of trace levels of N,N-diethyl-m-toluamide (DEET) in water is discussed. The method utilizes an on-line preconcentration column in series with high performance liquid chromatography (HPLC) and UV photodiode array detection. DEET, a common insect repel...

  4. Allergen micro-array detection of specific IgE-reactivity in Chinese allergy patients

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yi-wu; ZHONG Nan-shan; Michael D Spangfort; LI Jing; LAI Xu-xin; ZHAO De-yu; LIU Xiao-fan; LIN Xiao-ping; Birgitte Gjesing; Paola Palazzo; Adriano Mari

    2011-01-01

    Background Allergen micro-arrays are powerful tools for screening of serum IgE-reactivity.In this study allergen micro-arrays were used to identify dominating IgE-binding allergens and cross-reactivity patterns among selected Chinese allergy patients.Methods The study was conducted using patient sera from the cities of Guangzhou,Nanjing,Chengdu and Shenyang.In total 100 sera with Dermatophagoides pteronyssinus (Der p) specific IgE-levels higher than 50 kU/L were selected for testing against 103 individual allergens.Results Among 100 selected patients, 95% showed IgE-reactivity towards house-dust mite allergens Dermatophagoides farinae (Der f) 1,Der f 2 and Der p 2 and 94% were IgE positive against Der p 1,and 60% of sera contained IgE reacting against allergen Euroglyphus maynei (Eur m) 2.IgE against cat allergen,Felisdomesticus (Fel d)1,was seen in 20%.Only 2% showed specific IgE-reactivity to Der p 10,a panallergen belonging to the tropomyosin family.Serum IgE-reactivity towards other allergens was in general low.IgE-reactivity against pollen allergens showed geographic differences.Conclusions This study clearly confirms that group 1 and group 2 are major allergens of house dust mites.These selected house-dust mite allergy patients are close to being mono-sensitized.Der p 10 is not an important allergen for cross-reactivity.Specific IgE-sensitization towards pollen allergens is low in southern China compared to other regions.The prevalence of food and stinging insect allergens known to give rise to IgE-mediated cross-reactivity is 2% or less.

  5. Bacterial discrimination by means of a universal array approach mediated by LDR (ligase detection reaction

    Directory of Open Access Journals (Sweden)

    Consolandi Clarissa

    2002-09-01

    Full Text Available Abstract Background PCR amplification of bacterial 16S rRNA genes provides the most comprehensive and flexible means of sampling bacterial communities. Sequence analysis of these cloned fragments can provide a qualitative and quantitative insight of the microbial population under scrutiny although this approach is not suited to large-scale screenings. Other methods, such as denaturing gradient gel electrophoresis, heteroduplex or terminal restriction fragment analysis are rapid and therefore amenable to field-scale experiments. A very recent addition to these analytical tools is represented by microarray technology. Results Here we present our results using a Universal DNA Microarray approach as an analytical tool for bacterial discrimination. The proposed procedure is based on the properties of the DNA ligation reaction and requires the design of two probes specific for each target sequence. One oligo carries a fluorescent label and the other a unique sequence (cZipCode or complementary ZipCode which identifies a ligation product. Ligated fragments, obtained in presence of a proper template (a PCR amplified fragment of the 16s rRNA gene contain either the fluorescent label or the unique sequence and therefore are addressed to the location on the microarray where the ZipCode sequence has been spotted. Such an array is therefore "Universal" being unrelated to a specific molecular analysis. Here we present the design of probes specific for some groups of bacteria and their application to bacterial diagnostics. Conclusions The combined use of selective probes, ligation reaction and the Universal Array approach yielded an analytical procedure with a good power of discrimination among bacteria.

  6. Impedance biosensor for the rapid detection of Listeria spp. based on aptamer functionalized Pt-interdigitated microelectrodes array

    Science.gov (United States)

    Sidhu, R.; Rong, Y.; Vanegas, D. C.; Claussen, J.; McLamore, E. S.; Gomes, C.

    2016-05-01

    Listeria monocytogenes is one of the most common causes of food illness deaths worldwide, with multiple outbreaks in the United States alone. Current methods to detect foodborne pathogens are laborious and can take several hours to days to produce results. Thus, faster techniques are needed to detect bacteria within the same reliability level as traditional techniques. This study reports on a rapid, accurate, and sensitive aptamer biosensor device for Listeria spp. detection based on platinum interdigitated array microelectrodes (Pt-IDEs). Pt-IDEs with different geometric electrode gaps were fabricated by lithographic techniques and characterized by cyclic voltammetric (CV), electrochemical impedance spectroscopy (EIS), and potential amperometry (DCPA) measurements of reversible redox species. Based on these results, 50 μm Pt-IDE was chosen to further functionalize with a Listeria monocytogenes DNA aptamer selective to the cell surface protein internalin A, via metal-thiol self-assembly at the 5' end of the 47-mer's. EIS analysis was used to detect Listeria spp. without the need for label amplification and pre-concentration steps. The optimized aptamer concentration of 800 nM was selected to capture the bacteria through internalin A binding and the aptamer hairpin structure near the 3' end. The aptasensor was capable of detecting a wide range of bacteria concentration from 10 to 106 CFU/mL at lower detection limit of 5.39 +/- 0.21 CFU/mL with sensitivity of 268.1 +/- 25.40 (Ohms/log [CFU/mL]) in 17 min. The aptamer based biosensor offers a portable, rapid and sensitive alternative for food safety applications with one of the lowest detection limits reported to date.

  7. A Versatile Multiple Target Detection System Based on DNA Nano-assembled Linear FRET Arrays.

    Science.gov (United States)

    Li, Yansheng; Du, Hongwu; Wang, Wenqian; Zhang, Peixun; Xu, Liping; Wen, Yongqiang; Zhang, Xueji

    2016-05-27

    DNA molecules have been utilized both as powerful synthetic building blocks to create nanoscale architectures and as inconstant programmable templates for assembly of biosensors. In this paper, a versatile, scalable and multiplex detection system is reported based on an extending fluorescent resonance energy transfer (FRET) cascades on a linear DNA assemblies. Seven combinations of three kinds of targets are successfully detected through the changes of fluorescence spectra because of the three-steps FRET or non-FRET continuity mechanisms. This nano-assembled FRET-based nanowire is extremely significant for the development of rapid, simple and sensitive detection system. The method used here could be extended to a general platform for multiplex detection through more-step FRET process.

  8. Recent developments in pathogen detection arrays: implications for fungal plant pathogens and use in practica

    NARCIS (Netherlands)

    Lievens, B.; Thomma, B.P.H.J.

    2005-01-01

    The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection, an

  9. Detection and Separation of Speech Events in Meeting Recordings Using a Microphone Array

    National Research Council Canada - National Science Library

    Asano, Futoshi; Yamamoto, Kiyoshi; Ogata, Jun; Yamada, Miichi; Nakamura, Masami

    2007-01-01

    ...) framework is proposed. The main feature of this method is that all the information necessary for the adaptation of ABF, including microphone calibration, is obtained from meeting recordings based on the results of speech-event detection...

  10. The First Monolithic Silicon Carbide Active Pixel Sensor Array for Solar Blind UV Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will address the needs of space astronomy, military threat detection, and scientific research for image...

  11. Single molecule detection using charge-coupled device array technology. Technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Denton, M.B.

    1992-07-29

    A technique for the detection of single fluorescent chromophores in a flowing stream is under development. This capability is an integral facet of a rapid DNA sequencing scheme currently being developed by Los Alamos National Laboratory. In previous investigations, the detection sensitivity was limited by the background Raman emission from the water solvent. A detection scheme based on a novel mode of operating a Charge-Coupled Device (CCD) is being developed which should greatly enhance the discrimination between fluorescence from a single molecule and the background Raman scattering from the solvent. Register shifts between rows in the CCD are synchronized with the sample flow velocity so that fluorescence from a single molecule is collected in a single moving charge packet occupying an area approaching that of a single pixel while the background is spread evenly among a large number of pixels. Feasibility calculations indicate that single molecule detection should be achieved with an excellent signal-to-noise ratio.

  12. CRISPR Spacer Arrays for Detection of Viral Signatures from Acidic Hot Springs

    Science.gov (United States)

    Snyder, J. C.; Bateson, M. M.; Suciu, D.; Young, M. J.

    2010-04-01

    Viruses are the most abundant life-like entities on the planet Earth. Using CRISPR spacer sequences, we have developed a microarray-based approach to detecting viral signatures in the acidic hot springs of Yellowstone.

  13. Microfluidic cartridge with integrated array of amorphous silicon photosensors for chemiluminescence detection of viral DNA

    Directory of Open Access Journals (Sweden)

    M. Zangheri

    2016-03-01

    With this system, taking advantage of oligoprobes specificity, chemiluminescence detectability, and photosensor sensitivity, accurate quantification of target analytes down to 70 pmol L−1 was obtained for each B19 DNA genotype, with high specificity and multiplexing ability. Results confirm the good detection capabilities and assay applicability of the proposed system, prompting the development of innovative portable analytical devices with enhanced sensitivity and multiplexed capabilities.

  14. Crosstalk between adjacent nanopores in a solid-state membrane array for multi-analyte high-throughput biomolecule detection

    Science.gov (United States)

    Raza, Muhammad Usman; Saleem, Sajid; Ali, Waqas; Iqbal, Samir M.

    2016-08-01

    Single nanopores are used to detect a variety of biological molecules. The modulations in ionic current under applied bias across the nanopore contain important information about translocating species, thus providing single analyte detection. These systems are, however, challenged in practical situations where multiple analytes have to be detected at high throughput. This paper presents the analysis of a multi-nanopore system that can be used for the detection of analytes with high throughput. As a scalable model, two nanopores were simulated in a single solid-state membrane. The interactions of the electric fields at the mouths of the individual nanopores were analyzed. The data elucidated the electrostatic properties of the nanopores from a single membrane and provided a framework to calculate the -3 dB distance, akin to the Debye length, from one nanopore to the other. This distance was the minimum distance between the adjacent nanopores such that their individual electric fields did not significantly interact with one another. The results can help in the optimal experimental design to construct solid-state nanopore arrays for any given nanopore size and applied bias.

  15. Mini-Array of Multiple Tumor-Associated Antigens to Enhance Autoantibody Detection for Immunodiagnosis of Hepatocellular Carcinoma

    Science.gov (United States)

    Zhang, Jian-Ying

    2009-01-01

    Liver cancer, especially hepatocellular carcinoma (HCC), is particularly prevalent in Africa and Asia. HCC affects the Hispanic population of the United States at a rate double that of the white population. The majority of people with HCC will die within 1 year of its detection. This high case-fatality rate can in part be attributed to lack of diagnostic methods that allow early detection. How to establish a methodology to identify the high-risk individuals for HCC remains to be investigated. The multi-factorial and multi-step nature in the molecular pathogenesis of human cancers must be taken into account in both the design and interpretation of studies to identify markers which will be useful for early detection of cancer. Our recent studies demonstrated that a mini-array of multiple tumor-associated antigens (TAAs) might enhance autoantibody detection for diagnosis of HCC, especially for the alpha fetoprotein (AFP)-negative cases. It also suggested that different types of cancer might require different panels of TAAs to achieve the sensitivity and specificity required to make immunodiagnosis a feasible adjunct to tumor diagnosis. PMID:17289549

  16. Detection of Brominated By-Products Using a Sensor Array Based on Nanostructured Thin Films of Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Ladislau Martin-Neto

    2007-12-01

    Full Text Available The detection of the carcinogenic trihalomethanes (THM in public water supplysystems using low-cost equipment has become an essential feature, since these compoundsmay be generated as by-products of water-treatment processes. Here we report on a sensorarray that extends the concept of an “electronic tongue” to detect small amounts ofbromoform, bromodichloromethane and dibromochloromethane, with detection limits aslow as 0.02 mg L-1. The sensor array was made up of 10 sensing units, in whichnanostructured films of conducting and natural polymers were deposited onto goldinterdigitated electrodes. The principle of detection was impedance spectroscopy, withmeasurements carried out in the range between 1 Hz to 1 MHz. Using data at 1 kHz, atwhich the electrical response varied considerably by changing the analyte, we demonstratedwith principal component analysis (PCA that samples with the 3 brominatedtrihalomethanes can be distinguished from each other and for various concentrations.

  17. Tailored surface-enhanced Raman nanopillar arrays fabricated by laser-assisted replication for biomolecular detection using organic semiconductor lasers.

    Science.gov (United States)

    Liu, Xin; Lebedkin, Sergei; Besser, Heino; Pfleging, Wilhelm; Prinz, Stephan; Wissmann, Markus; Schwab, Patrick M; Nazarenko, Irina; Guttmann, Markus; Kappes, Manfred M; Lemmer, Uli

    2015-01-27

    Organic semiconductor distributed feedback (DFB) lasers are of interest as external or chip-integrated excitation sources in the visible spectral range for miniaturized Raman-on-chip biomolecular detection systems. However, the inherently limited excitation power of such lasers as well as oftentimes low analyte concentrations requires efficient Raman detection schemes. We present an approach using surface-enhanced Raman scattering (SERS) substrates, which has the potential to significantly improve the sensitivity of on-chip Raman detection systems. Instead of lithographically fabricated Au/Ag-coated periodic nanostructures on Si/SiO2 wafers, which can provide large SERS enhancements but are expensive and time-consuming to fabricate, we use low-cost and large-area SERS substrates made via laser-assisted nanoreplication. These substrates comprise gold-coated cyclic olefin copolymer (COC) nanopillar arrays, which show an estimated SERS enhancement factor of up to ∼ 10(7). The effect of the nanopillar diameter (60-260 nm) and interpillar spacing (10-190 nm) on the local electromagnetic field enhancement is studied by finite-difference-time-domain (FDTD) modeling. The favorable SERS detection capability of this setup is verified by using rhodamine 6G and adenosine as analytes and an organic semiconductor DFB laser with an emission wavelength of 631.4 nm as the external fiber-coupled excitation source.

  18. Ultrahigh Detective Heterogeneous Photosensor Arrays with In-Pixel Signal Boosting Capability for Large-Area and Skin-Compatible Electronics.

    Science.gov (United States)

    Kim, Jaehyun; Kim, Jaekyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Myungwon; Moon, Juhyuk; Yang, Lin; Kim, Myung-Gil; Kim, Yong-Hoon; Park, Sung Kyu

    2016-04-01

    An ultra-thin and large-area skin-compatible heterogeneous organic/metal-oxide photosensor array is demonstrated which is capable of sensing and boosting signals with high detectivity and signal-to-noise ratio. For the realization of ultra-flexible and high-sensitive heterogeneous photosensor arrays on a polyimide substrate having organic sensor arrays and metal-oxide boosting circuitry, solution-processing and room-temperature alternating photochemical conversion routes are applied. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Fundamental research on the label-free detection of protein adsorption using near-infrared light-responsive plasmonic metal nanoshell arrays with controlled nanogap

    OpenAIRE

    Uchida, Shuhei; Zettsu, Nobuyuki; Endo, Katsuyoshi; Yamamura, Kazuya

    2013-01-01

    In this work, we focused on the label-free detection of simple protein binding using near-infrared light-responsive plasmonic nanoshell arrays with a controlled interparticle distance. The nanoshell arrays were fabricated by a combination of colloidal self-assembly and subsequent isotropic helium plasma etching under atmospheric pressure. The diameter, interparticle distance, and shape of nanoshells can be tuned with nanometric accuracy by changing the experimental conditions. The Au, Ag, and...

  20. Metallic nanocone array photonic substrate for high-uniformity surface deposition and optical detection of small molecules

    Science.gov (United States)

    Coppé, Jean-Philippe; Xu, Zhida; Chen, Yi; Logan Liu, G.

    2011-06-01

    Molecular probe arrays printed on solid surfaces such as DNA, peptide, and protein microarrays are widely used in chemical and biomedical applications especially genomic and proteomic studies (Pollack et al 1999 Nat. Genet. 23 41-6, Houseman et al 2002 Nat. Biotechnol. 20 270-4, Sauer et al 2005 Nat. Rev. Genet. 6 465-76) as well as surface imaging and spectroscopy (Mori et al 2008 Anal. Biochem. 375 223-31, Liu et al 2006 Nat. Nanotechnol. 1 47-52, Liu 2010 IEEE J. Sel. Top. Quantum Electron. 16 662-71). Unfortunately the printed molecular spots on solid surfaces often suffer low distribution uniformity due to the lingering 'coffee stain' (Deegan et al 1997 Nature 389 827-9) problem of molecular accumulations and blotches, especially around the edge of deposition spots caused by solvent evaporation and convection processes. Here we present, without any surface chemistry modification, a unique solid surface of high-aspect-ratio silver-coated silicon nanocone arrays that allows highly uniform molecular deposition and thus subsequent uniform optical imaging and spectroscopic molecular detection. Both fluorescent Rhodamine dye molecules and unlabeled oligopeptides are printed on the metallic nanocone photonic substrate surface as circular spot arrays. In comparison with the printed results on ordinary glass slides and silver-coated glass slides, not only high printing density but uniform molecular distribution in every deposited spot is achieved. The high-uniformity and repeatability of molecular depositions on the 'coffee stain'-free nanocone surface is confirmed by laser scanning fluorescence imaging and surface enhanced Raman imaging experiments. The physical mechanism for the uniform molecular deposition is attributed to the superhydrophobicity and localized pinned liquid-solid-air interface on the silver-coated silicon nanocone surface. The unique surface properties of the presented nanocone surface enabled high-density, high-uniformity probe spotting beneficial

  1. Metallic nanocone array photonic substrate for high-uniformity surface deposition and optical detection of small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Coppe, Jean-Philippe [Kinogea Inc., 2168 Shattuck Ave, Berkeley, CA 94704 (United States); Xu Zhida; Chen Yi; Logan Liu, G, E-mail: loganliu@illinois.edu [Micro and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL (United States)

    2011-06-17

    Molecular probe arrays printed on solid surfaces such as DNA, peptide, and protein microarrays are widely used in chemical and biomedical applications especially genomic and proteomic studies (Pollack et al 1999 Nat. Genet. 23 41-6, Houseman et al 2002 Nat. Biotechnol. 20 270-4, Sauer et al 2005 Nat. Rev. Genet. 6 465-76) as well as surface imaging and spectroscopy (Mori et al 2008 Anal. Biochem. 375 223-31, Liu et al 2006 Nat. Nanotechnol. 1 47-52, Liu 2010 IEEE J. Sel. Top. Quantum Electron. 16 662-71). Unfortunately the printed molecular spots on solid surfaces often suffer low distribution uniformity due to the lingering 'coffee stain' (Deegan et al 1997 Nature 389 827-9) problem of molecular accumulations and blotches, especially around the edge of deposition spots caused by solvent evaporation and convection processes. Here we present, without any surface chemistry modification, a unique solid surface of high-aspect-ratio silver-coated silicon nanocone arrays that allows highly uniform molecular deposition and thus subsequent uniform optical imaging and spectroscopic molecular detection. Both fluorescent Rhodamine dye molecules and unlabeled oligopeptides are printed on the metallic nanocone photonic substrate surface as circular spot arrays. In comparison with the printed results on ordinary glass slides and silver-coated glass slides, not only high printing density but uniform molecular distribution in every deposited spot is achieved. The high-uniformity and repeatability of molecular depositions on the 'coffee stain'-free nanocone surface is confirmed by laser scanning fluorescence imaging and surface enhanced Raman imaging experiments. The physical mechanism for the uniform molecular deposition is attributed to the superhydrophobicity and localized pinned liquid-solid-air interface on the silver-coated silicon nanocone surface. The unique surface properties of the presented nanocone surface enabled high-density, high-uniformity probe

  2. Detection of herbicide subclasses by an optical multibiosensor based on an array of photosystem II mutants.

    Science.gov (United States)

    Giardi, Maria Teresa; Guzzella, Licia; Euzet, Pierre; Rouillon, Regis; Esposito, Dania

    2005-07-15

    Massive use of herbicides in agriculture over the last few decades has become a serious environmental problem. The residual concentration of these compounds frequently exceeds the maximum admissible concentration in drinking water for human consumption and is a real environmental risk for the aquatic ecosystem. Herbicides inhibiting photosynthesis via targeting photosystem II function still represent the basic means of weed control. A multibiosensor was constructed for detecting herbicides using as biosensing elements photosynthetic preparations coupled to an optical fluorescence transduction system (Giardi et al. EU patent EP1134585, 01830148.1-2204); this paper is about its application in the detection of herbicide subclasses in river water. Photosynthetic material was immobilized on a silicio septum inside a series of flow cells, close to diodes so as to activate photosystem II (PSII) fluorescence. The principle of the detection was based on the factthat herbicides selectively modify PSII fluorescence activity. The multibiosensor has the original feature of being able to distinguish the subclasses of the photosynthetic herbicides by using specific immobilized biomediators isolated from mutated organisms. This setup resulted in a reusable, portable multibiosensor for the detection of herbicide subclasses with a half-life of 54 h for spinach thylakoids and limit of detection of 3 x 10(-9) M for herbicides present in river water.

  3. Array formatting of the heat-transfer method (HTM) for the detection of small organic molecules by molecularly imprinted polymers.

    Science.gov (United States)

    Wackers, Gideon; Vandenryt, Thijs; Cornelis, Peter; Kellens, Evelien; Thoelen, Ronald; De Ceuninck, Ward; Losada-Pérez, Patricia; van Grinsven, Bart; Peeters, Marloes; Wagner, Patrick

    2014-06-20

    In this work we present the first steps towards a molecularly imprinted polymer (MIP)-based biomimetic sensor array for the detection of small organic molecules via the heat-transfer method (HTM). HTM relies on the change in thermal resistance upon binding of the target molecule to the MIP-type receptor. A flow-through sensor cell was developed, which is segmented into four quadrants with a volume of 2.5 μL each, allowing four measurements to be done simultaneously on a single substrate. Verification measurements were conducted, in which all quadrants received a uniform treatment and all four channels exhibited a similar response. Subsequently, measurements were performed in quadrants, which were functionalized with different MIP particles. Each of these quadrants was exposed to the same buffer solution, spiked with different molecules, according to the MIP under analysis. With the flow cell design we could discriminate between similar small organic molecules and observed no significant cross-selectivity. Therefore, the MIP array sensor platform with HTM as a readout technique, has the potential to become a low-cost analysis tool for bioanalytical applications.

  4. Simultaneous determination of seven main alkaloids of Chelidonium majus L. by ultra-performance LC with photodiode-array detection.

    Science.gov (United States)

    Gu, Yue; Qian, Dawei; Duan, Jin-ao; Wang, Zhenzhong; Guo, Jianming; Tang, Yuping; Guo, Sheng

    2010-04-01

    A simple and rapid method for the simultaneous determination of seven isoquinoline alkaloids, protopine, chelidonine, coptisine, stylopine, sanguinarine, berberine, and chelerythrine, in Chelidonium majus L. (Ch. majus) samples by ultra-performance LC method with photodiode array detection is described. The baseline separation of these compounds was performed with (A) acetonitrile-(B) ammonium acetate (10 mM, adjusted to pH 3.0 with acetic acid) as the mobile phase using a C18 RP column (2.1x100 mm, 1.7 microm). Optimized conditions resulted in excellent peak shapes. The seven alkaloids were completely separated within 20 min. Good linear behaviors (r > or = 0.9992) over the investigated concentration ranges were observed for all the analytes. Validation proved the repeatability of the method was good and recovery was satisfactory. The validated method was successfully applied for 20 batches of Ch. majus. These results demonstrated that the ultra-performance LC photodiode array method proposed was very useful in the analysis and quality control of Ch. majus.

  5. Algorithm for real-time detection of signal patterns using phase synchrony: an application to an electrode array

    Science.gov (United States)

    Sadeghi, Saman; MacKay, William A.; van Dam, R. Michael; Thompson, Michael

    2011-02-01

    Real-time analysis of multi-channel spatio-temporal sensor data presents a considerable technical challenge for a number of applications. For example, in brain-computer interfaces, signal patterns originating on a time-dependent basis from an array of electrodes on the scalp (i.e. electroencephalography) must be analyzed in real time to recognize mental states and translate these to commands which control operations in a machine. In this paper we describe a new technique for recognition of spatio-temporal patterns based on performing online discrimination of time-resolved events through the use of correlation of phase dynamics between various channels in a multi-channel system. The algorithm extracts unique sensor signature patterns associated with each event during a training period and ranks importance of sensor pairs in order to distinguish between time-resolved stimuli to which the system may be exposed during real-time operation. We apply the algorithm to electroencephalographic signals obtained from subjects tested in the neurophysiology laboratories at the University of Toronto. The extension of this algorithm for rapid detection of patterns in other sensing applications, including chemical identification via chemical or bio-chemical sensor arrays, is also discussed.

  6. Simultaneous analysis of six aristolochic acids and five aristolactams in herbal plants and their preparations by high-performance liquid chromatography-diode array detection-fluorescence detection.

    Science.gov (United States)

    Yuan, Jinbin; Liu, Qian; Zhu, Weifeng; Ding, Li; Tang, Fei; Yao, Shouzhuo

    2008-02-22

    Aristolochic acid analogues, including aristolochic acids (AAs) and aristolactams (ALs), are known to be nephrotoxic, carcinogenic and mutagenic. In this paper, a high-performance liquid chromatography-diode array detection-fluorescence detection (HPLC-DAD-FLD) method was developed for the simultaneous determination of six AAs together with five ALs. Baseline separation was obtained on an ODS C18 analytical column with 0.2% HAc/methanol gradient elution. The hyphenation of DAD and FLD allows the method to directly meet the analysis requirements of most herbal plants with high sensitivity and selectivity. For trace analysis, aristolochic acids were reduced to their corresponding aritstolactams in acidic solution containing iron powder, and then high sensitive detection and quantification were carried out. The method was successfully validated in the matrices of various Aristolochiaceae plants and their preparations. Linearities of around 3-4 orders of magnitude were obtained with correlation coefficients exceeding 0.9970. The detection limits were decreased to 0.2ng/ml. Satisfactory intra-day and inter-day precisions were achieved with RSDs less than 5.74%, and the average recovery factors were in the range of 94.5-99.2%.

  7. 用电生的Fe(Ⅱ)-EDTA络合物在Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc缓冲溶液中精密库仑滴定金%Precise Coulometric Titration of Gold with Electrogenerated Fe(Ⅱ)-EDTA Complex in Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc Buffer Medium

    Institute of Scientific and Technical Information of China (English)

    董守安; 吴长蓉

    2003-01-01

    A method of precise coulometric titration of Au(Ⅲ)was studied with electrogenerating Fe(Ⅱ)-EDTA as titrant in Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc buffer solution.For the determination of gold in the range of 5.2 to 17.0mg ,the relative average errors and RSD of the results were≤0.03%(n=5),using potentiometric end point detection.The proposed method has been applied to the precise analysis of gold content in pure gold,gold alloys and jewelry with good selectivity.The theoretical basis for electrogeneration Fe(Ⅱ)-EDTA complex as a coulometric titrant was also discussed and a useful conclusion was obtained.%提出了在Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc缓冲溶液中利用电生Fe(Ⅱ)-ED-TA络合物精密库仑滴定Au的方法.采用电位法检测终点,测定范围在5.2~17.0mg Au时,相对平均误差和标准偏差≤0.03%.方法可用于纯金、金合金和首饰等材料中Au含量的精密分析,选择性很好.讨论了电生Fe(Ⅱ)-EDTA络合物作库仑滴定剂的理论基础,获得了有益的结论.

  8. Proof of concept of impact detection in composites using fiber bragg grating arrays.

    Science.gov (United States)

    Gomez, Javier; Jorge, Iagoba; Durana, Gaizka; Arrue, Jon; Zubia, Joseba; Aranguren, Gerardo; Montero, Ander; López, Ion

    2013-09-09

    Impact detection in aeronautical structures allows predicting their future reliability and performance. An impact can produce microscopic fissures that could evolve into fractures or even the total collapse of the structure, so it is important to know the location and severity of each impact. For this purpose, optical fibers with Bragg gratings are used to analyze each impact and the vibrations generated by them. In this paper it is proven that optical fibers with Bragg gratings can be used to detect impacts, and also that a high-frequency interrogator is necessary to collect valuable information about the impacts. The use of two interrogators constitutes the main novelty of this paper.

  9. Pulsar timing noise and the minimum observation time to detect gravitational waves with pulsar timing arrays

    CERN Document Server

    Lasky, Paul D; Ravi, Vikram; Hobbs, George

    2015-01-01

    The sensitivity of pulsar timing arrays to gravitational waves is, at some level, limited by timing noise. Red timing noise - the stochastic wandering of pulse arrival times with a red spectrum - is prevalent in slow-spinning pulsars and has been identified in many millisecond pulsars. Phenomenological models of timing noise, such as from superfluid turbulence, suggest that the timing noise spectrum plateaus below some critical frequency, $f_c$, potentially aiding the hunt for gravitational waves. We examine this effect for individual pulsars by calculating minimum observation times, $T_{\\rm min}(f_c)$, over which the gravitational wave signal becomes larger than the timing noise plateau. We do this in two ways: 1) in a model-independent manner, and 2) by using the superfluid turbulence model for timing noise as an example to illustrate how neutron star parameters can be constrained. We show that the superfluid turbulence model can reproduce the data qualitatively from a number of pulsars observed as part of ...

  10. Platinum plasmonic nanostructure arrays for massively parallel single-molecule detection based on enhanced fluorescence measurements.

    Science.gov (United States)

    Saito, Toshiro; Takahashi, Satoshi; Obara, Takayuki; Itabashi, Naoshi; Imai, Kazumichi

    2011-11-04

    We fabricated platinum bowtie nanostructure arrays producing fluorescence enhancement and evaluated their performance using two-photon photoluminescence and single-molecule fluorescence measurements. A comprehensive selection of suitable materials was explored by electromagnetic simulation and Pt was chosen as the plasmonic material for visible light excitation near 500 nm, which is preferable for multicolor dye-labeling applications like DNA sequencing. The observation of bright photoluminescence (λ = 500-600 nm) from each Pt nanostructure, induced by irradiation at 800 nm with a femtosecond laser pulse, clearly indicates that a highly enhanced local field is created near the Pt nanostructure. The attachment of a single dye molecule was attempted between the Pt triangles of each nanostructure by using selective immobilization chemistry. The fluorescence intensities of the single dye molecule localized on the nanostructures were measured. A highly enhanced fluorescence, which was increased by a factor of 30, was observed. The two-photon photoluminescence intensity and fluorescence intensity showed qualitatively consistent gap size dependence. However, the average fluorescence enhancement factor was rather repressed even in the nanostructure with the smallest gap size compared to the large growth of photoluminescence. The variation of the position of the dye molecule attached to the nanostructure may influence the wide distribution of the fluorescence enhancement factor and cause the rather small average value of the fluorescence enhancement factor.

  11. Prospects for gravitational-wave detection and supermassive black hole astrophysics with pulsar timing arrays

    CERN Document Server

    Ravi, V; Shannon, R M; Hobbs, G

    2014-01-01

    [Abridged] Large-area sky surveys show that massive galaxies undergo at least one major merger in a Hubble time. If all massive galaxies host central supermassive black holes (SMBHs), as is inferred from observations in the local Universe, it is likely that there is a population of binary SMBHs at the centres of galaxy merger remnants. Numerous authors have proposed pulsar timing array (PTA) experiments to measure the gravitational wave (GW) emission from binary SMBHs. In this paper, using the latest observational estimates for a range of galaxy properties and scaling relations, we predict the amplitude of the GW background generated by the binary SMBH population. We also predict counts of individual binary SMBH GW sources. We assume that all binary SMBHs are in circular orbits evolving under GW emission alone, which is likely to be correct for binaries emitting GWs at frequencies >~10^-8 Hz. Our fiducial model results in a characteristic strain amplitude of the GW background of A_yr=1.2(+0.6-0.3)*10^-15 at a...

  12. MEDEA: a multi element detector array for gamma ray and light charged particle detection at the LNS-Catania

    Science.gov (United States)

    Migneco, E.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Maiolino, C.; Piattelli, P.; Raia, G.; Sapienza, P.

    1992-04-01

    A 4 π highly granular Mutli Element DEtector Array (MEDEA) for γ-rays and light charged particles is described. Its basic configuration consists of 180 barium fluoride scintillator crystals, arranged in the shape of a ball, plus a forward angle wall of 120 phoswich detectors. The inner radius of the ball (22 cm) and the distance of the wall from the target (55 cm) allow the placement of other detectors.in the inner volume. The whole detection system operates under vacuum inside a large scattering chamber. Dedicated electronics has been designed and realized. It includes a powerful hardware second level trigger and preanalysis system, which allows on-line event selection, and a modular VME-bus based data acquisition system. In-beam performances of the system are also described.

  13. How to Detect the Signatures of Self-Gravitating Circumstellar Discs with the Atacama Large Millimetre/sub-millimetre Array

    CERN Document Server

    Dipierro, Giovanni; Testi, Leonardo; Monsalvo, Itziar de Gregorio

    2014-01-01

    In this paper we present simulated Atacama Large Millimetre/sub-millimetre Array (ALMA) observations of self-gravitating circumstellar discs with different properties in size, mass and inclination, located in four of the most extensively studied and surveyed star-forming regions. Starting from a Smoothed Particle Hydrodynamics (SPH) simulation and representative dust opacities, we have initially constructed maps of the expected emission at sub-mm wavelengths of a large sample of discs with different properties. We have then simulated realistic observations of discs as they may appear with ALMA using the Common Astronomy Software Application ALMA simulator. We find that, with a proper combination of antenna configuration and integration time, the spiral structure characteristic of self-gravitating discs is readily detectable by ALMA over a wide range of wavelengths at distances comparable to TW Hydrae ($\\sim 50 \\,$pc), Taurus - Auriga and Ophiucus ($\\sim 140 \\,$pc) star-forming regions. However, for discs loca...

  14. Study of SiPM custom arrays for scintillation light detection in a Liquid Argon Time Projection Chamber

    Science.gov (United States)

    Cervi, T.; Babicz, M. E.; Bonesini, M.; Falcone, A.; Kose, U.; Nessi, M.; Menegolli, A.; Pietropaolo, F.; Raselli, G. L.; Rossella, M.; Torti, M.; Zani, A.

    2017-03-01

    Liquid Argon Time Projection Chamber (LAr-TPC) technique has been established as one of the most promising for the next generation of experiments dedicated to neutrino and rare-event physics. LAr-TPCs have the fundamental feature to be able to both collect the charge and the scintillation light produced after the passage of a ionizing particle inside the Argon volume. Scintillation light is traditionally detected by large surface Photo-Multiplier Tubes (PMTs) working at cryogenic temperature. Silicon Photo-Multipliers (SiPMs) are semiconductor-based devices with performances comparable to the PMT ones, but with very small active areas. For this reason we built a prototype array composed by SiPMs connected in different electrical configurations. We present results on preliminary tests made with four SiPMs, connected both in parallel and in series configurations, deployed into a 50 liters LAr-TPC exposed to cosmic rays at CERN.

  15. A Matched Filter Technique for Slow Radio Transient Detection and First Demonstration with the Murchison Widefield Array

    Science.gov (United States)

    Feng, L.; Vaulin, R.; Hewitt, J. N.; Remillard, R.; Kaplan, D. L.; Murphy, Tara; Kudryavtseva, N.; Hancock, P.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Gaensler, B. M.; Greenhill, L. J.; Hazelton, B. J.; Johnston-Hollitt, M.; Lonsdale, C. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.

    2017-03-01

    Many astronomical sources produce transient phenomena at radio frequencies, but the transient sky at low frequencies (technique for detecting radio transients that is based on temporal matched filters applied directly to time series of images, rather than relying on source-finding algorithms applied to individual images. This technique has well-defined statistical properties and is applicable to variable and transient searches for both confusion-limited and non-confusion-limited instruments. Using the Murchison Widefield Array as an example, we demonstrate that the technique works well on real data despite the presence of classical confusion noise, sidelobe confusion noise, and other systematic errors. We searched for transients lasting between 2 minutes and 3 months. We found no transients and set improved upper limits on the transient surface density at 182 MHz for flux densities between ∼20 and 200 mJy, providing the best limits to date for hour- and month-long transients.

  16. Sea trial of Delphinus; a towed array for marine mammal detection

    NARCIS (Netherlands)

    Kromjongh, J.; Spellen, M. van; Beerens, S.P.; IJsselmuide, S.P. van

    2005-01-01

    World-wide a concern exists about the influence of man-made sound on marine life and particularly on marine mammals. One of the acoustic polluters of the world’s oceans is high-power active sonar. An early warning system at the sound source, which is based on passive detection of marine mammals, cou

  17. 6-Plex microsphere immunoassay with imaging planar array detection for mycotoxins in barley

    NARCIS (Netherlands)

    Peters, J.; Cardall, A.; Haasnoot, W.; Nielen, M.W.F.

    2014-01-01

    Mycotoxins are produced by fungi as secondary metabolites. They often multi-contaminate food and feed commodities posing a health risk to humans and animals. A fast and easy to apply multiplex screening of these commodities could be useful to detect multi-contamination. For this, we developed a semi

  18. A Coded Aperture Compressive Imaging Array and Its Visual Detection and Tracking Algorithms for Surveillance Systems

    Directory of Open Access Journals (Sweden)

    Hanxiao Wu

    2012-10-01

    Full Text Available In this paper, we propose an application of a compressive imaging system to the problem of wide-area video surveillance systems. A parallel coded aperture compressive imaging system is proposed to reduce the needed high resolution coded mask requirements and facilitate the storage of the projection matrix. Random Gaussian, Toeplitz and binary phase coded masks are utilized to obtain the compressive sensing images. The corresponding motion targets detection and tracking algorithms directly using the compressive sampling images are developed. A mixture of Gaussian distribution is applied in the compressive image space to model the background image and for foreground detection. For each motion target in the compressive sampling domain, a compressive feature dictionary spanned by target templates and noises templates is sparsely represented. An l1 optimization algorithm is used to solve the sparse coefficient of templates. Experimental results demonstrate that low dimensional compressed imaging representation is sufficient to determine spatial motion targets. Compared with the random Gaussian and Toeplitz phase mask, motion detection algorithms using a random binary phase mask can yield better detection results. However using random Gaussian and Toeplitz phase mask can achieve high resolution reconstructed image. Our tracking algorithm can achieve a real time speed that is up to 10 times faster than that of the l1 tracker without any optimization.

  19. Gold-coated carbon nanotube electrode arrays: Immunosensors for impedimetric detection of bone biomarkers.

    Science.gov (United States)

    Ramanathan, Madhumati; Patil, Mitali; Epur, Rigved; Yun, Yeoheung; Shanov, Vasselin; Schulz, Mark; Heineman, William R; Datta, Moni K; Kumta, Prashant N

    2016-03-15

    C-terminal telopeptide (cTx), a fragment generated during collagen degradation, is a key biomarker of bone resorption during the bone remodeling process. The presence of varying levels of cTx in the bloodstream can hence be indicative of abnormal bone metabolism. This study focuses on the development of an immunosensor utilizing carbon nanotube (CNT) electrodes coated with gold nanoparticles for the detection of cTx, which could ultimately lead to the development of an inexpensive and rapid point-of-care (POC) tool for bone metabolism detection and prognostics. Electrochemical impedance spectroscopy (EIS) was implemented to monitor and detect the antigen-antibody binding events occurring on the surface of the gold-deposited CNT electrode. Type I cTx was used as the model protein to test the developed sensor. The sensor was accordingly characterized at various stages of development for evaluation of the optimal sensor performance. The biosensor could detect cTx levels as low as 0.05 ng/mL. The feasibility of the sensor for point-of-care (POC) applications was further demonstrated by determining the single frequency showing maximum changes in impedance, which was determined to be 18.75 Hz.

  20. Redox cycling with facing interdigitated array electrodes as a method for selective detection of redox species

    NARCIS (Netherlands)

    Dam, V.A.T.; Olthuis, W.; Berg, van den A.

    2007-01-01

    A pair of interdigitated ultramicroelectrodes (UMEs) is used to electrochemically detect a weak reductor ( dopamine) in the presence of a stronger one (K-4[ Fe(CN)(6)]). In the mixture of both reductors, one of the two interdigitated electrodes ( the generator electrode) is used to oxidize both spec

  1. A Wireless Sensor System for Real-Time Monitoring and Fault Detection of Motor Arrays

    Science.gov (United States)

    Medina-García, Jonathan; Sánchez-Rodríguez, Trinidad; Galán, Juan Antonio Gómez; Delgado, Aránzazu; Gómez-Bravo, Fernando; Jiménez, Raúl

    2017-01-01

    This paper presents a wireless fault detection system for industrial motors that combines vibration, motor current and temperature analysis, thus improving the detection of mechanical faults. The design also considers the time of detection and further possible actions, which are also important for the early detection of possible malfunctions, and thus for avoiding irreversible damage to the motor. The remote motor condition monitoring is implemented through a wireless sensor network (WSN) based on the IEEE 802.15.4 standard. The deployed network uses the beacon-enabled mode to synchronize several sensor nodes with the coordinator node, and the guaranteed time slot mechanism provides data monitoring with a predetermined latency. A graphic user interface offers remote access to motor conditions and real-time monitoring of several parameters. The developed wireless sensor node exhibits very low power consumption since it has been optimized both in terms of hardware and software. The result is a low cost, highly reliable and compact design, achieving a high degree of autonomy of more than two years with just one 3.3 V/2600 mAh battery. Laboratory and field tests confirm the feasibility of the wireless system. PMID:28245623

  2. Research and Development of Non-Spectroscopic MEMS-Based Sensor Arrays for Targeted Gas Detection

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; McCall, S K

    2011-10-24

    The ability to monitor the integrity of gas volumes is of interest to the stockpile surveillance community. Specifically, the leak detection of noble gases, at relevant concentration ranges and distinguished from other chemical species that may be simultaneously present, is particularly challenging. Aside from the laboratory-based method of gas chromatography-mass spectrometry (GC-MS), where samples may be collected by solid-phase microextraction (SPME) or cryofocusing, the other major approaches for gas-phase detection employ lasers typically operating in the mid-infrared wavelength region. While mass spectrometry can readily detect noble gases - the helium leak detector is an obvious example - laser-based methods such as infrared (IR) or Raman spectroscopy are completely insensitive to them as their monatomic nature precludes a non-zero dipole moment or changes in polarizability upon excitation. Therefore, noble gases can only be detected by one of two methods: (1) atomic emission spectroscopies which require the generation of plasmas through laser-induced breakdown, electrical arcing, or similar means; (2) non-spectroscopic methods which measure one or more physical properties (e.g., mass, thermal conductivity, density). In this report, we present our progress during Fiscal Year 2011 (FY11) in the research and development of a non-spectroscopic method for noble gas detection. During Fiscal Year 2010 (FY10), we demonstrated via proof-of-concept experiments that the combination of thermal conductivity detection (TCD) and coating-free damped resonance detection (CFDRD) using micro-electromechanical systems (MEMS) could provide selective sensing of these inert species. Since the MEMS-based TCD technology was directly adapted from a brassboard prototype commissioned by a previous chemical sensing project, FY11 efforts focused on advancing the state of the newer CFDRD method. This work, guided by observations previously reported in the open literature, has not only

  3. Direct detection of precursors of gas giants formed by gravitational instability with the Atacama Large Millimetre/sub-millimetre Array

    CERN Document Server

    Mayer, Lucio; Pineda, Jaime E; Wadsley, James

    2016-01-01

    Phases of gravitational instability are expected in the early phases of disk evolution, when the disk mass is still a substantial fraction of the mass of the star. Disk fragmentation into sub-stellar objects could occur in the cold exterior part of the disk. Direct detection of massive gaseous clumps on their way to collapse into gas giant planets would offer an unprecedented test of the disk instability model. Here we use state-of-the-art 3D radiation-hydro simulations of disks undergoing fragmentation into massive gas giants, post-processed with the RADMC-3D ray-tracing code to produce dust continuum emission maps. These are then fed into the Common Astronomy Software Applications (CASA) ALMA simulator. The synthetic maps show that both overdense spiral arms and actual clumps at different stages of collapse can be detected with the Atacama Large Millimetre/sub-millimetre Array (ALMA) in the full configuration at the distance of the Ophiuchus star forming region (125 pc). The detection of clumps is particula...

  4. Fisher Matrix Predictions for Detecting the Cosmological 21-cm Signal with the Ooty Wide Field Array (OWFA)

    Indian Academy of Sciences (India)

    S. Bharadwaj; A. K. Sarkar; Sk. Saiyad Ali

    2015-09-01

    We have used the Fisher matrix formalism to quantify the prospects of detecting the = 3.35 redshifted 21-cm HI power spectrum with the upcoming radio-imterferometric array OWFA. OWFA’s frequency and baseline coverage spans comoving Fourier modes in the range 1.8 × 10−2 ≤ k ≤ 2.7 Mpc−1. The OWFA HI signal, however, is predominantly from the range ≤ 0.2 Mpc−1. The larger modes, though abundant, do not contribute much to the HI signal. In this work, we have focused on combining the entire signal to achieve a detection. We find that a 5 - detection of HI is possible with ∼ 150 h of observations, here $A^{2}_{\\text{HI}}$ is the amplitude of the HI power spectrum. We have also carried out a joint analysis for HI and the redshift space distortion parameter. Our study shows that OWFA is very sensitive to the amplitude of the HI power spectrum. However, the anisotropic distribution of the k modes does not make it very suitable for measuring .

  5. Fisher matrix predictions for detecting the cosmological 21 cm signal with the Ooty Wide Field Array (OWFA)

    CERN Document Server

    Bharadwaj, Somnath; Ali, Sk Saiyad

    2015-01-01

    We have used the Fisher matrix formalism to quantify the prospects of detecting the z = 3.35 redshifted 21-cm HI power spectrum with the upcoming radio-imterferometric array OWFA. OWFA's frequency and baseline coverage spans comoving Fourier modes (k) in the range 0.018 to 2.7 [1/Mpc]. The OWFA HI signal, however, is predominantly from the range k below 0.2 [1/Mpc]. The larger modes, though abundant, do not contribute much to the HI signal. In this work we have focused on combining the entire signal to achieve a detection. We find that a 5-sigma detection of A_{HI} is possible with ~ 150 hr of observations, here A^2 _{HI} is the amplitude of the HI power spectrum. We have also carried out a joint analysis for A_{HI} and the redshift space distortion parameter. Our study shows that OWFA is very sensitive to the amplitude of the HI power spectrum. However, the anisotropic distribution of the k modes does not make it very suitable for measuring the redshift space distortion parameter.

  6. Polymer nanopillar-gold arrays as surface-enhanced Raman spectroscopy substrate for the simultaneous detection of multiple genes.

    Science.gov (United States)

    Picciolini, Silvia; Mehn, Dora; Morasso, Carlo; Vanna, Renzo; Bedoni, Marzia; Pellacani, Paola; Marchesini, Gerardo; Valsesia, Andrea; Prosperi, Davide; Tresoldi, Cristina; Ciceri, Fabio; Gramatica, Furio

    2014-10-28

    In our study, 2D nanopillar arrays with plasmonic crystal properties are optimized for surface-enhanced Raman spectroscopy (SERS) application and tested in a biochemical assay for the simultaneous detection of multiple genetic leukemia biomarkers. The special fabrication process combining soft lithography and plasma deposition techniques allows tailoring of the structural and chemical parameters of the crystal surfaces. In this way, it has been possible to tune the plasmonic resonance spectral position close to the excitation wavelength of the monochromatic laser light source in order to maximize the enhancing properties of the substrate. Samples are characterized by scanning electron microscopy and reflectance measurements and tested for SERS activity using malachite green. Besides, as the developed substrate had been prepared on a simple glass slide, SERS detection from the support side is also demonstrated. The optimized substrate is functionalized with thiol-modified capture oligonucleotides, and concentration-dependent signal of the target nucleotide is detected in a sandwich assay with labeled gold nanoparticles. Gold nanoparticles functionalized with different DNA and various Raman reporters are applied in a microarray-based assay recognizing a disease biomarker (Wilms tumor gene) and housekeeping gene expressions in the same time on spatially separated microspots. The multiplexing performance of the SERS-based bioassay is illustrated by distinguishing Raman dyes based on their complex spectral fingerprints.

  7. Utility of SNP arrays in detecting, quantifying, and determining meiotic origin of tetrasomy 12p in blood from individuals with Pallister-Killian syndrome.

    Science.gov (United States)

    Conlin, Laura K; Kaur, Maninder; Izumi, Kosuke; Campbell, Lindsey; Wilkens, Alisha; Clark, Dinah; Deardorff, Matthew A; Zackai, Elaine H; Pallister, Phillip; Hakonarson, Hakon; Spinner, Nancy B; Krantz, Ian D

    2012-12-01

    Identification of the isochromosome 12p (i(12p)) associated with Pallister-Killian syndrome is complicated by the low frequency of this supernumerary chromosome in PHA stimulated peripheral blood lymphocytes, and frequently requires cytogenetic analysis of fibroblast cells. Recently, it has been shown that array CGH techniques are able to detect tetrasomy 12p in peripheral blood, even when not identified by traditional cytogenetic techniques. We studied 15 patients with a previous cytogenetic and clinical diagnosis of Pallister-Killian syndrome using genome-wide SNP arrays to investigate the ability of this platform to identify the i(12p) in blood and tissue. Array analysis verified tetrasomy 12p in all samples from fibroblasts, but was only able to detect it in 46% of blood samples. The genotyping information available from the SNP arrays allowed for the detection of as low as 5% mosaicism, as well as suggesting a Meiosis II origin for the isochromosome in the majority of patients. Analysis of the percentage of abnormal cells with patient age at time of study suggests that the frequency of the i(12p) decreased with age in blood, but not in fibroblasts. These highlight the power of SNP arrays in detecting and characterizing the isochromosome 12p in Pallister-Killian syndrome as well as underscoring the important utility of traditional cytogenetic techniques.

  8. Study and building of a detection array for delayed neutrons: TONNERRE; Etude et realisation d`un ensemble de detection pour neutrons retardes: TONNERRE

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Thierry [Lab. de Physique Corpusculaire, Caen Univ., 14 - Caen (France)

    1998-11-09

    This work has been undertaken within a French-Romanian collaboration in order to build a high efficiency detector array for delayed neutrons: barrel-shaped TONNERRE. Some neutron-rich nuclei decay through 1, 2 or 3 neutron emission after {beta}{sup -} decay. More exotic nuclei will be produced by SPIRAL at GANIL. An array with high efficiency and good resolution is then required. Thirty two BC400 plastic scintillators (160 x 20 x 4 cm{sup 3}) allow us to get the time of flight neutron spectra. They are bent for uniform flight path and viewed by a photomultiplier tube at both ends. Simulations have allowed to establish scintillator size and to minimize light attenuation. Intrinsic efficiency and crosstalk have been measured with {sup 252}Cf and compared to GEANT. 1 to 5 MeV neutrons are detected with good timing and position properties. Other counters will be built for neutrons from 300 keV to 1 MeV. Planned to run at several particle accelerators (GANIL, CERN, and others), TONNERRE is modular and many geometries are possible. (author) 48 refs., 78 figs., 20 tabs.

  9. Detection and estimation of volcanic eruption onset and mass flow rate using weather radar and infrasonic array

    Science.gov (United States)

    Marzano, Frank S.; Mereu, Luigi; Montopoli, Mario; Picciotti, Errico; Di Fabio, Saverio; Bonadonna, Costanza; Marchetti, Emanuele; Ripepe, Maurizio

    2015-04-01

    associated with explosive eruptions is generally produced by the rapid expansion of the gas-particle mixture within the conduit and, in consequence, it is related to the dynamics of the volume outflow and thus to the intensity of the eruption. Infrasound is closely linked to the magma fragmentation process. By combining data from ground surveys and remote sensing measurements, it is possible to gain more insights into tephra detection and distribution. Microwave scanning radars can be exploited to extract tephra spatial-temporal distribution in proximity of the volcano vent. Radar detection of ash clouds is a cumbersome problem, as their signature can be confused with that of hydrometeors. On the other hand, infrasonic arrays can provide a very accurate signal about the onset of a volcanic fountain, even though not necessarily discriminating between lava and ash eruptions. In this work we illustrate the methodology to combine microwave radar data with infrasonic measurements using, as a case study, the eruption of 2010 Eyjafjallajökull. The probabilistic detection module of the Volcanic Ash Radar Retrieval (VARR) physically-based technique is illustrated. The ash detection methodology is based on the temporal analysis of radar volumes of reflectivity and geographical information for the considered specific area. The infrasonic array signal is coupled with radar data to enhance the VARR probability of ash detection. Moreover, mass flow rates estimated from radar measurements are compared with those retrieved from infrasonic arrays and derived from simplified analytical eruption models.

  10. Specificity and Strain-Typing Capabilities of Nanorod Array-Surface Enhanced Raman Spectroscopy for Mycoplasma pneumoniae Detection.

    Directory of Open Access Journals (Sweden)

    Kelley C Henderson

    Full Text Available Mycoplasma pneumoniae is a cell wall-less bacterial pathogen of the human respiratory tract that accounts for > 20% of all community-acquired pneumonia (CAP. At present the most effective means for detection and strain-typing is quantitative polymerase chain reaction (qPCR, which can exhibit excellent sensitivity and specificity but requires separate tests for detection and genotyping, lacks standardization between available tests and between labs, and has limited practicality for widespread, point-of-care use. We have developed and previously described a silver nanorod array-surface enhanced Raman Spectroscopy (NA-SERS biosensing platform capable of detecting M. pneumoniae with statistically significant specificity and sensitivity in simulated and true clinical throat swab samples, and the ability to distinguish between reference strains of the two main genotypes of M. pneumoniae. Furthermore, we have established a qualitative lower endpoint of detection for NA-SERS of < 1 genome equivalent (cell/μl and a quantitative multivariate detection limit of 5.3 ± 1 cells/μl. Here we demonstrate using partial least squares- discriminatory analysis (PLS-DA of sample spectra that NA-SERS correctly identified M. pneumoniae clinical isolates from globally diverse origins and distinguished these from a panel of 12 other human commensal and pathogenic mycoplasma species with 100% cross-validated statistical accuracy. Furthermore, PLS-DA correctly classified by strain type all 30 clinical isolates with 96% cross-validated accuracy for type 1 strains, 98% cross-validated accuracy for type 2 strains, and 90% cross-validated accuracy for type 2V strains.

  11. Microarray MAPH: accurate array-based detection of relative copy number in genomic DNA

    Directory of Open Access Journals (Sweden)

    Chan Alan

    2006-06-01

    Full Text Available Abstract Background Current methods for measurement of copy number do not combine all the desirable qualities of convenience, throughput, economy, accuracy and resolution. In this study, to improve the throughput associated with Multiplex Amplifiable Probe Hybridisation (MAPH we aimed to develop a modification based on the 3-Dimensional, Flow-Through Microarray Platform from PamGene International. In this new method, electrophoretic analysis of amplified products is replaced with photometric analysis of a probed oligonucleotide array. Copy number analysis of hybridised probes is based on a dual-label approach by comparing the intensity of Cy3-labelled MAPH probes amplified from test samples co-hybridised with similarly amplified Cy5-labelled reference MAPH probes. The key feature of using a hybridisation-based end point with MAPH is that discrimination of amplified probes is based on sequence and not fragment length. Results In this study we showed that microarray MAPH measurement of PMP22 gene dosage correlates well with PMP22 gene dosage determined by capillary MAPH and that copy number was accurately reported in analyses of DNA from 38 individuals, 12 of which were known to have Charcot-Marie-Tooth disease type 1A (CMT1A. Conclusion Measurement of microarray-based endpoints for MAPH appears to be of comparable accuracy to electrophoretic methods, and holds the prospect of fully exploiting the potential multiplicity of MAPH. The technology has the potential to simplify copy number assays for genes with a large number of exons, or of expanded sets of probes from dispersed genomic locations.

  12. Simultaneous detection for three kinds of veterinary drugs: Chloramphenicol, clenbuterol and 17-beta-estradiol by high-throughput suspension array technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu Nan; Su Pu [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China); Gao Zhixian [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China)], E-mail: gaozhx@163.com; Zhu Maoxiang; Yang Zhihua; Pan Xiujie [Institute of Radiation Medicine, Beijing 100850 (China); Fang Yanjun; Chao Fuhuan [Institute of Hygiene and Environmental Medicine, Tianjin 300050 (China)

    2009-01-19

    Suspension array technology for simultaneous detection of three kinds of veterinary drugs, chloramphenicol (CAP), clenbuterol and 17-beta-estradiol has been developed. Conjugates of chloramphenicol and clenbuterol coupled with bovine serum albumin were synthesized and purified. Probes of suspension array were constituted by coupling the three conjugates on the fluorescent microspheres/beads and the microstructures of the beads' surface were observed by scanning electron microscopy which was a direct confirmation for the successful conjugates' coupling. The optimal addition of conjugates and the amounts of antibodies were optimized and selected, respectively. Standard curves were plotted and the coefficient of determination-R{sup 2} was greater than 0.989 which suggested good logistic correlation. The detection ranges for the three veterinary drugs are 40-6.25 x 10{sup 5} ng L{sup -1}, 50-7.81 x 10{sup 5} ng L{sup -1} and 1 x 10{sup 3-}7.29 x 10{sup 5} ng L{sup -1}, respectively and the lowest detection limits (LDLs) of them are 40, 50 and 1000 ng L{sup -1}, respectively. The suspension array is specific and has no significant cross-reactivity with other chemicals. Meanwhile, unknown samples were detected by suspension array and ELISA in comparison with each other. The errors between found and real for the detection of the unknown samples were relatively small to both of the two methods, whereas, the detection ranges of suspension array are broader and sensitive than that of the traditional ELISA. The high-throughput suspension array is proved to be a novel method for multi-analysis of veterinary drugs with simple operation, high sensitivity and low cost.

  13. Proof of Concept of Impact Detection in Composites Using Fiber Bragg Grating Arrays

    Directory of Open Access Journals (Sweden)

    Ander Montero

    2013-09-01

    Full Text Available Impact detection in aeronautical structures allows predicting their future reliability and performance. An impact can produce microscopic fissures that could evolve into fractures or even the total collapse of the structure, so it is important to know the location and severity of each impact. For this purpose, optical fibers with Bragg gratings are used to analyze each impact and the vibrations generated by them. In this paper it is proven that optical fibers with Bragg gratings can be used to detect impacts, and also that a high-frequency interrogator is necessary to collect valuable information about the impacts. The use of two interrogators constitutes the main novelty of this paper.

  14. On detection of the stochastic gravitational-wave background using the Parkes pulsar timing array

    CERN Document Server

    Yardley, D R B; Hobbs, G B; Verbiest, J P W; Manchester, R N; van Straten, W; Jenet, F A; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Champion, D J; Hotan, A W; Oslowski, S; Reynolds, J E; Sarkissian, J M

    2011-01-01

    We search for the signature of an isotropic stochastic gravitational-wave background in pulsar timing observations using a frequency-domain correlation technique. These observations, which span roughly 12 yr, were obtained with the 64-m Parkes radio telescope augmented by public domain observations from the Arecibo Observatory. A wide range of signal processing issues unique to pulsar timing and not previously presented in the literature are discussed. These include the effects of quadratic removal, irregular sampling, and variable errors which exacerbate the spectral leakage inherent in estimating the steep red spectrum of the gravitational-wave background. These observations are found to be consistent with the null hypothesis, that no gravitational-wave background is present, with 76 percent confidence. We show that the detection statistic is dominated by the contributions of only a few pulsars because of the inhomogeneity of this data set. The issues of detecting the signature of a gravitational-wave backg...

  15. Simultaneous Detection of Sulfamethoxazole, Diclofenac, Carbamazepine, and Bezafibrate by Solid Phase Extraction and High Performance Liquid Chromatography with Diode Array Detection

    Science.gov (United States)

    Zhou, Z.; Jiang, J.-Q.

    2014-05-01

    A method of solid phase extraction (SPE) coupled with high performance liquid chromatography and diode array detection (HPLC-DAD) was studied for the simultaneous determination of sulfamethoxazole (SMX), diclofenac (DCF), carbamazepine (CBZ), and bezafi brate (BZF) in test solutions. The target compounds were extracted by SPE from samples, and the resulting elutes were analyzed using a HPLC-DAD system at wavelengths of 270, 280, 290, and 230 nm for SMX, DCF, CBZ, and BZF, respectively. This method shows good recoveries for SMX, DCF, CBZ, and BZF with mean recoveries of 89.7 ± 9.3%, 86.1 ± 7.6%, 95.0 ± 6.5%, and 94.0 ± 5.4%, respectively.

  16. Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.C.

    1998-03-01

    Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ({sup 10}B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where {sup 3}He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector`s response and filtering based on the presence of a simultaneous energy deposition corresponding to the {sup 10}B(n,alpha) reaction products in the plastic scintillator (93 keV{sub ee}) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including {sup 137}Cs, {sup 54}Mn, AmLi, and {sup 252}Cf. Results of this study indicate that a neutron-capture probability of {approximately}10% and a die-away time of {approximately}10 {micro}s are possible with a 4-detector array with a detector volume of 1600 cm{sup 3}. Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 {micro}s are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this

  17. Coulometry for the detection of water content in archaeological findings

    Directory of Open Access Journals (Sweden)

    Vincenza Crupi

    2016-06-01

    Full Text Available In the present work, we performed coulometric measurements to detect the water content in archaeological pottery in order to get information on the manufacture technique. The samples under study were the so-called "Ionian Cups" coming from various archaeological sites in eastern Sicily (South-Italy. In particular, we tentatively achieved the estimation of firing temperatures of the archaeological samples by comparing the coulometric results with those obtained in the case of raw materials fired under controlled conditions. The results were in good agreement with those previously obtained on the same samples by Small Angle Neutron Scattering (SANS. It is worth underlying that for the first time, the detection of water content as revealed by this analytical technique was related to archaeometric issues.

  18. A male newborn with VACTERL association and Fanconi anemia with a FANCB deletion detected by array comparative genomic hybridization (aCGH).

    Science.gov (United States)

    Umaña, Luis A; Magoulas, Pilar; Bi, Weimin; Bacino, Carlos A

    2011-12-01

    We report on a male newborn with multiple congenital abnormalities consistent with the diagnosis of VACTERL association (vertebral, anal, cardiac, tracheo-esophageal fistula, renal, and limb anomalies), who had Fanconi anemia (complementation group B) recognized by the detection of a deletion in chromosome Xp22.2 using an oligonucleotide array. The diagnosis of Fanconi anemia was confirmed by increased chromosomal breakage abnormalities observed in cultured cells that were treated with cross-linking agents. This is the first report in the literature of Fanconi anemia complementation group B detected by oligonucleotide array testing postnatally.

  19. Improved Shear Wave Motion Detection Using Pulse-Inversion Harmonic Imaging With a Phased Array Transducer.

    Science.gov (United States)

    Pengfei Song; Heng Zhao; Urban, Matthew W; Manduca, Armando; Pislaru, Sorin V; Kinnick, Randall R; Pislaru, Cristina; Greenleaf, James F; Shigao Chen

    2013-12-01

    Ultrasound tissue harmonic imaging is widely used to improve ultrasound B-mode imaging quality thanks to its effectiveness in suppressing imaging artifacts associated with ultrasound reverberation, phase aberration, and clutter noise. In ultrasound shear wave elastography (SWE), because the shear wave motion signal is extracted from the ultrasound signal, these noise sources can significantly deteriorate the shear wave motion tracking process and consequently result in noisy and biased shear wave motion detection. This situation is exacerbated in in vivo SWE applications such as heart, liver, and kidney. This paper, therefore, investigated the possibility of implementing harmonic imaging, specifically pulse-inversion harmonic imaging, in shear wave tracking, with the hypothesis that harmonic imaging can improve shear wave motion detection based on the same principles that apply to general harmonic B-mode imaging. We first designed an experiment with a gelatin phantom covered by an excised piece of pork belly and show that harmonic imaging can significantly improve shear wave motion detection by producing less underestimated shear wave motion and more consistent shear wave speed measurements than fundamental imaging. Then, a transthoracic heart experiment on a freshly sacrificed pig showed that harmonic imaging could robustly track the shear wave motion and give consistent shear wave speed measurements of the left ventricular myocardium while fundamental imaging could not. Finally, an in vivo transthoracic study of seven healthy volunteers showed that the proposed harmonic imaging tracking sequence could provide consistent estimates of the left ventricular myocardium stiffness in end-diastole with a general success rate of 80% and a success rate of 93.3% when excluding the subject with Body Mass Index higher than 25. These promising results indicate that pulse-inversion harmonic imaging can significantly improve shear wave motion tracking and thus potentially

  20. An aptamer based competition assay for protein detection using CNT activated gold-interdigitated capacitor arrays.

    Science.gov (United States)

    Qureshi, Anjum; Roci, Irena; Gurbuz, Yasar; Niazi, Javed H

    2012-04-15

    An aptamer can specifically bind to its target molecule, or hybridize with its complementary strand. A target bound aptamer complex has difficulty to hybridize with its complementary strand. It is possible to determine the concentration of target based on affinity separation system for the protein detection. Here, we exploited this property using C-reactive protein (CRP) specific RNA aptamers as probes that were immobilized by physical adsorption on carbon nanotubes (CNTs) activated gold interdigitated electrodes of capacitors. The selective binding ability of RNA aptamer with its target molecule was determined by change in capacitance after allowing competitive binding with CRP and complementary RNA (cRNA) strands in pure form and co-mixtures (CRP:cRNA=0:1, 1:0, 1:1, 1:2 and 2:1). The sensor showed significant capacitance change with pure forms of CRP/cRNA while responses reduced considerably in presence of CRP:cRNA in co-mixtures (1:1 and 1:2) because of the binding competition. At a critical CRP:cRNA ratio of 2:1, the capacitance response was dramatically lost because of the dissociation of adsorbed aptamers from the sensor surface to bind when excess CRP. Binding assays showed that the immobilized aptamers had strong affinity for cRNA (K(d)=1.98 μM) and CRP molecules (K(d)=2.4 μM) in pure forms, but low affinity for CRP:cRNA ratio of 2:1 (K(d)=8.58 μM). The dynamic detection range for CRP was determined to be 1-8 μM (0.58-4.6 μg/capacitor). The approach described in this study is a sensitive label-free method to detect proteins based on affinity separation of target molecules that can potentially be used for probing molecular interactions.