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Sample records for optic-linear array detection

  1. Selective and sensitive speciation analysis of Cr(VI) and Cr(III) in water samples by fiber optic-linear array detection spectrophotometry after ion pair based-surfactant assisted dispersive liquid-liquid microextraction.

    PubMed

    Yousefi, Seyedeh Mahboobeh; Shemirani, Farzaneh

    2013-06-15

    A simple ion pair based-surfactant assisted dispersive liquid-liquid microextraction (IP-SA-DLLME) was evaluated for extraction and preconcentration of Cr(VI) and Cr(III) in aqueous samples. In this method, which was used for the first time for chromium speciation analysis, sodium dodecyl sulfate (SDS) was used as both ion-pairing and disperser agent. Cr(VI) ions were converted into their cationic complex with 1,5-diphenylcarbazide (DPC) and then extracted into 1-octanol dispersed in aqueous solution. Cr(III) ion also can be determined by this procedure after oxidation to Cr(VI). After extraction and phase separation, upper organic phase was transferred to a micro cell of a fiber optic-linear array detection spectrophotometry (FO-LADS). The effects of various parameters on the extraction recovery were investigated. Under the optimized conditions and preconcentration of 10 mL of sample, the enrichment factor of 159 and the detection limit of 0.05 μgL(-1) were obtained. Validation of the method was performed by spiking-recovery method and comparison of results with those obtained by ET-AAS method.

  2. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry

    NASA Astrophysics Data System (ADS)

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-01

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r2 = 0.998) in the range of 3.0-85.0 μg L-1 with a detection limit of 0.7 μg L-1 for preconcentration of 25.0 mL of the sample and the relative standard deviation (n = 6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments.

  3. Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry.

    PubMed

    Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

    2015-08-01

    A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r(2)=0.998) in the range of 3.0-85.0 μg L(-1) with a detection limit of 0.7 μg L(-1) for preconcentration of 25.0 mL of the sample and the relative standard deviation (n=6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments.

  4. Array for detecting microbes

    DOEpatents

    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.

  5. Sensor arrays for detecting microorganisms

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

    2000-01-01

    A sensor array for detecting a microorganism comprising first and second sensors electrically connected to an electrical measuring apparatus, wherein the sensors comprise a region of nonconducting organic material and a region of conducting material compositionally that is different than the nonconducting organic material and an electrical path through the regions of nonconducting organic material and the conducting material. A system for identifying microorganisms using the sensor array, a computer and a pattern recognition algorithm, such as a neural net are also disclosed.

  6. Quantitative detection of protein arrays.

    PubMed

    Levit-Binnun, Nava; Lindner, Ariel B; Zik, Ory; Eshhar, Zelig; Moses, Elisha

    2003-03-15

    We introduce a quantitative method that utilizes scanning electron microscopy for the analysis of protein chips (SEMPC). SEMPC is based upon counting target-coated gold particles interacting specifically with ligands or proteins arrayed on a derivative microscope glass slide by utilizing backscattering electron detection. As model systems, we quantified the interactions of biotin and streptavidin and of an antibody with its cognate hapten. Our method gives quantitative molecule-counting capabilities with an excellent signal-to-noise ratio and demonstrates a broad dynamic range while retaining easy sample preparation and realistic automation capability. Increased sensitivity and dynamic range are achieved in comparison to currently used array detection methods such as fluorescence, with no signal bleaching, affording high reproducibility and compatibility with miniaturization. Thus, our approach facilitates the determination of the absolute number of molecules bound to the chip rather than their relative amounts, as well as the use of smaller samples.

  7. Delamination Detection Using Guided Wave Phased Arrays

    NASA Technical Reports Server (NTRS)

    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.

  8. Noise limitations in optical linear algebra processors.

    PubMed

    Batsell, S G; Jong, T L; Walkup, J F; Krile, T F

    1990-05-10

    A general statistical noise model is presented for optical linear algebra processors. A statistical analysis which includes device noise, the multiplication process, and the addition operation is undertaken. We focus on those processes which are architecturally independent. Finally, experimental results which verify the analytical predictions are also presented.

  9. Development of a novel mixed hemimicelles dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene for the separation and preconcentration of fluoxetine in different matrices before its determination by fiber optic linear array spectrophotometry and mode-mismatched thermal lens spectroscopy.

    PubMed

    Kazemi, Elahe; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-28

    This study aims at developing a novel, sensitive, fast, simple and convenient method for separation and preconcentration of trace amounts of fluoxetine before its spectrophotometric determination. The method is based on combination of magnetic mixed hemimicelles solid phase extraction and dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene as a sorbent. The magnetic graphene was synthesized by a simple coprecipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The retained analyte was eluted using a 100 μL mixture of methanol/acetic acid (9:1) and converted into fluoxetine-β-cyclodextrin inclusion complex. The analyte was then quantified by fiber optic linear array spectrophotometry as well as mode-mismatched thermal lens spectroscopy (TLS). The factors affecting the separation, preconcentration and determination of fluoxetine were investigated and optimized. With a 50 mL sample and under optimized conditions using the spectrophotometry technique, the method exhibited a linear dynamic range of 0.4-60.0 μg L(-1), a detection limit of 0.21 μg L(-1), an enrichment factor of 167, and a relative standard deviation of 2.1% and 3.8% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. However, with thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 0.05-300 μg L(-1), a detection limit of 0.016 μg L(-1) and a relative standard deviation of 3.8% and 5.6% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. The method was successfully applied to determine fluoxetine in pharmaceutical formulation, human urine and environmental water samples. PMID:26755141

  10. Development of a novel mixed hemimicelles dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene for the separation and preconcentration of fluoxetine in different matrices before its determination by fiber optic linear array spectrophotometry and mode-mismatched thermal lens spectroscopy.

    PubMed

    Kazemi, Elahe; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-28

    This study aims at developing a novel, sensitive, fast, simple and convenient method for separation and preconcentration of trace amounts of fluoxetine before its spectrophotometric determination. The method is based on combination of magnetic mixed hemimicelles solid phase extraction and dispersive micro solid phase extraction using 1-hexadecyl-3-methylimidazolium bromide coated magnetic graphene as a sorbent. The magnetic graphene was synthesized by a simple coprecipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The retained analyte was eluted using a 100 μL mixture of methanol/acetic acid (9:1) and converted into fluoxetine-β-cyclodextrin inclusion complex. The analyte was then quantified by fiber optic linear array spectrophotometry as well as mode-mismatched thermal lens spectroscopy (TLS). The factors affecting the separation, preconcentration and determination of fluoxetine were investigated and optimized. With a 50 mL sample and under optimized conditions using the spectrophotometry technique, the method exhibited a linear dynamic range of 0.4-60.0 μg L(-1), a detection limit of 0.21 μg L(-1), an enrichment factor of 167, and a relative standard deviation of 2.1% and 3.8% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. However, with thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 0.05-300 μg L(-1), a detection limit of 0.016 μg L(-1) and a relative standard deviation of 3.8% and 5.6% (n = 6) at 60 μg L(-1) level of fluoxetine for intra- and inter-day analyses, respectively. The method was successfully applied to determine fluoxetine in pharmaceutical formulation, human urine and environmental water samples.

  11. Optical linear algebra processors - Architectures and algorithms

    NASA Technical Reports Server (NTRS)

    Casasent, David

    1986-01-01

    Attention is given to the component design and optical configuration features of a generic optical linear algebra processor (OLAP) architecture, as well as the large number of OLAP architectures, number representations, algorithms and applications encountered in current literature. Number-representation issues associated with bipolar and complex-valued data representations, high-accuracy (including floating point) performance, and the base or radix to be employed, are discussed, together with case studies on a space-integrating frequency-multiplexed architecture and a hybrid space-integrating and time-integrating multichannel architecture.

  12. The Giant Radio Array for Neutrino Detection

    NASA Astrophysics Data System (ADS)

    Martineau-Huynh, Olivier; Kotera, Kumiko; Bustamente, Mauricio; Charrier, Didier; De Jong, Sijbrand; de Vries, Krijn D.; Fang, Ke; Feng, Zhaoyang; Finley, Chad; Gou, Quanbu; Gu, Junhua; Hanson, Jordan C.; Hu, Hongbo; Murase, Kohta; Niess, Valentin; Oikonomou, Foteini; Renault-Tinacci, Nicolas; Schmid, Julia; Timmermans, Charles; Wang, Zhen; Wu, Xiangping; Zhang, Jianli; Zhang, Yi

    2016-04-01

    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.

  13. Array biosensor for detection of toxins

    NASA Technical Reports Server (NTRS)

    Ligler, Frances S.; Taitt, Chris Rowe; Shriver-Lake, Lisa C.; Sapsford, Kim E.; Shubin, Yura; Golden, Joel P.

    2003-01-01

    The array biosensor is capable of detecting multiple targets rapidly and simultaneously on the surface of a single waveguide. Sandwich and competitive fluoroimmunoassays have been developed to detect high and low molecular weight toxins, respectively, in complex samples. Recognition molecules (usually antibodies) were first immobilized in specific locations on the waveguide and the resultant patterned array was used to interrogate up to 12 different samples for the presence of multiple different analytes. Upon binding of a fluorescent analyte or fluorescent immunocomplex, the pattern of fluorescent spots was detected using a CCD camera. Automated image analysis was used to determine a mean fluorescence value for each assay spot and to subtract the local background signal. The location of the spot and its mean fluorescence value were used to determine the toxin identity and concentration. Toxins were measured in clinical fluids, environmental samples and foods, with minimal sample preparation. Results are shown for rapid analyses of staphylococcal enterotoxin B, ricin, cholera toxin, botulinum toxoids, trinitrotoluene, and the mycotoxin fumonisin. Toxins were detected at levels as low as 0.5 ng mL(-1).

  14. Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

    PubMed

    Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples.

  15. Variable Gain Semiconductor Optical Linear Amplifier (OLA)

    NASA Astrophysics Data System (ADS)

    Michie, W. Craig; Kelly, Tony; Tomlinson, Andy; Andonovic, Ivan

    2002-12-01

    The semiconductor optical amplifier (SOA) is a versatile component that can be deployed to meet the expanding applications associated with the introduction of additional functionalities at the optical level in wavelength division multiplexed systems. The future network requires low cost, small footprint, directly controllable amplification throughout the different application layers from long haul through to metro; the intrinsic size and integration capability advantages will ensure that the SOA plays a key role in this evolution. In multi-wavelength gating/amplification applications the gain dynamics, oscillating at timescales comparable to that of the data which is being amplified, introduce issues of pattern dependent waveform distortion (patterning) in single channel, and inter-channel cross-talk in multi-wavelength cases which require management through careful SOA design and understanding of the network application scenarios. In this paper, an optical linear amplifier (OLA) architecture with the unique capability to provide variable gain whilst maintaining linear operation at high output saturation powers will be described. Initial characterisation results for the OLA will be presented.

  16. Detectability of Tengchong infrasound array in China

    NASA Astrophysics Data System (ADS)

    Su, Wei; Yuan, Songyong

    2016-04-01

    The Tengchong seismo-acoustic array located in southwest of China has been running for 5 years. We perform broadband (0.01-5 Hz) array processing with the infrasound continuous waveform data (from 1 January 2011 to 31 December 2015) using the Progressive Multi-Channel Correlation algorithm in 15 log-spaced frequency bands defined by Matoza et al.(2013).The detection results show microbaroms [0.1-0.5 Hz] come from azimuth between 180 and 240°during April to October related to the significant wave height in southern India ocean,but microbaroms come from azimuth between 30 and 90°during September to March related to the significant wave height in northern Pacific ocean. MAWs [0.01-0.1 Hz] come from azimuth between 270 and 360°,and between 90 and 160°. The detections with azimuth between 100 and 150° in December 2014 to January 2015 may be related to the several typhoons from the Western Pacific ocean. The PMCC results confirm that the coherent signals typically exhibit systematic seasonal variations.

  17. Parallel microfluidic arrays for SPRi detection

    NASA Astrophysics Data System (ADS)

    Ouellet, Eric; Lausted, Christopher; Lin, Tao; Yang, Cheng-Wei; Hood, Leroy; Lagally, Eric T.

    2010-04-01

    Surface Plasmon Resonance imaging (SPRi) is a label-free technique for the quantitation of binding affinities and concentrations for a wide variety of target molecules. Although SPRi is capable of determining binding constants for multiple ligands in parallel, current commercial instruments are limited to a single analyte stream and a limited number of ligand spots. Measurement of target concentration also requires the serial introduction of different target concentrations; such repeated experiments are conducted manually and are therefore time-intensive. Likewise, the equilibrium determination of concentration for known binding affinity requires long times due to diffusion-limited kinetics to a surface-immobilized ligand. We have developed an integrated microfluidic array using soft lithography techniques for SPRi-based detection and determination of binding affinities for DNA aptamers against human alphathrombin. The device consists of 264 element-addressable chambers of 700 pL each isolated by microvalves. The device also contains a dilution network for simultaneous interrogation of up to six different target concentrations, further speeding detection times. The element-addressable design of the array allows interrogation of multiple ligands against multiple targets, and analytes from individual chambers may be collected for downstream analysis.

  18. Parallel microfluidic arrays for SPRi detection

    NASA Astrophysics Data System (ADS)

    Ouellet, Eric; Lausted, Christopher; Hood, Leroy; Lagally, Eric T.

    2008-08-01

    Surface Plasmon Resonance imaging (SPRi) is a label-free technique for the quantitation of binding affinities and concentrations for a wide variety of target molecules. Although SPRi is capable of determining binding constants for multiple ligands in parallel, current commercial instruments are limited to a single analyte stream and a limited number of ligand spots. Measurement of target concentration also requires the serial introduction of different target concentrations; such repeated experiments are conducted manually and are therefore time-intensive. Likewise, the equilibrium determination of concentration for known binding affinity requires long times due to diffusion-limited kinetics to a surface-immobilized ligand. We have developed an integrated microfluidic array using soft lithography techniques for SPRi-based detection and determination of binding affinities for DNA aptamers against human alphathrombin. The device consists of 264 element-addressable chambers isolated by microvalves. The resulting 700 pL volumes surrounding each ligand spot promise to decrease measurement time through reaction rate-limited kinetics. The device also contains a dilution network for simultaneous interrogation of up to six different target concentrations, further speeding detection times. Finally, the element-addressable design of the array allows interrogation of multiple ligands against multiple targets.

  19. Sensor arrays for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

    1996-01-01

    Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g. electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

  20. Sensor array for toxic gas detection

    DOEpatents

    Stetter, Joseph R.; Zaromb, Solomon; Penrose, William R.

    1987-01-01

    A portable instrument for use in the field in detecting and identifying a hazardous component in air or other gas including an array of small sensors which upon exposure to the gas from a pattern of electrical responses, a source of standard response patterns characteristic of various components, and microprocessor means for comparing the sensor-formed response pattern with one or more standard patterns to thereby identify the component on a display. The number of responses may be increased beyond the number of sensors by changing the operating voltage, temperature or other condition associated with one or more sensors to provide a plurality of responses from each of one or more of the sensors. In one embodiment, the instrument is capable of identifying anyone of over 50-100 hazardous components.

  1. Graphene microelectrode arrays for neural activity detection.

    PubMed

    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. PMID:25712492

  2. Sensor arrays for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

    2000-01-01

    A sensor array for detecting an analyte in a fluid, comprising at least first and second chemically sensitive resistors electrically connected to an electrical measuring apparatus, wherein each of the chemically sensitive resistors comprises a mixture of nonconductive material and a conductive material. Each resistor provides an electrical path through the mixture of nonconductive material and the conductive material. The resistors also provide a difference in resistance between the conductive elements when contacted with a fluid comprising an analyte at a first concentration, than when contacted with an analyte at a second different concentration. A broad range of analytes can be detected using the sensors of the present invention. Examples of such analytes include, but are not limited to, alkanes, alkenes, alkynes, dienes, alicyclic hydrocarbons, arenes, alcohols, ethers, ketones, aldehydes, carbonyls, carbanions, polynuclear aromatics, organic derivatives, biomolecules, sugars, isoprenes, isoprenoids and fatty acids. Moreover, applications for the sensors of the present invention include, but are not limited to, environmental toxicology, remediation, biomedicine, material quality control, food monitoring and agricultural monitoring.

  3. Polymer-based sensor array for phytochemical detection

    NASA Astrophysics Data System (ADS)

    Weerakoon, Kanchana A.; Hiremath, Nitilaksha; Chin, Bryan A.

    2012-05-01

    Monitoring for the appearance of volatile organic compounds emitted by plants which correspond to time of first insect attack can be used to detect the early stages of insect infestation. This paper reports a chemical sensor array consisting of polymer based chemiresistor sensors that could detect insect infestation effectively. The sensor array consists of sensors with micro electronically fabricated interdigitated electrodes, and twelve different types of electro active polymer layers. The sensor array was cheap, easy to fabricate, and could be used easily in agricultural fields. The polymer array was found to be sensitive to a variety of volatile organic compounds emitted by plants including γ-terpinene α-pinene, pcymene, farnesene, limonene and cis-hexenyl acetate. The sensor array was not only able to detect but also distinguish between these compounds. The twelve sensors produced a resistance change for each of the analytes detected, and each of these responses together produced a unique fingerprint, enabling to distinguish among these chemicals.

  4. Terahertz line detection by a microlens array coupled photoconductive antenna array.

    PubMed

    Pradarutti, B; Müller, R; Freese, W; Matthäus, G; Riehemann, S; Notni, G; Nolte, S; Tünnermann, A

    2008-10-27

    We present THz ultrashort pulse detection by a photoconductive antenna array consisting of 16 photoconductive antennas. The efficient excitation of the photoconductive antennas has been realized by a microlens array which generates 16 single spots from the exciting fs-laser beam. This combination of optoelectronics and microoptics improves the detection efficiency by an order of magnitude in comparison to an excitation by a line focus. PMID:18958123

  5. Detecting and correcting hard errors in a memory array

    SciTech Connect

    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.

  6. Small Arrays for Seismic Intruder Detections: A Simulation Based Experiment

    NASA Astrophysics Data System (ADS)

    Pitarka, A.

    2014-12-01

    Seismic sensors such as geophones and fiber optic have been increasingly recognized as promising technologies for intelligence surveillance, including intruder detection and perimeter defense systems. Geophone arrays have the capability to provide cost effective intruder detection in protecting assets with large perimeters. A seismic intruder detection system uses one or multiple arrays of geophones design to record seismic signals from footsteps and ground vehicles. Using a series of real-time signal processing algorithms the system detects, classify and monitors the intruder's movement. We have carried out numerical experiments to demonstrate the capability of a seismic array to detect moving targets that generate seismic signals. The seismic source is modeled as a vertical force acting on the ground that generates continuous impulsive seismic signals with different predominant frequencies. Frequency-wave number analysis of the synthetic array data was used to demonstrate the array's capability at accurately determining intruder's movement direction. The performance of the array was also analyzed in detecting two or more objects moving at the same time. One of the drawbacks of using a single array system is its inefficiency at detecting seismic signals deflected by large underground objects. We will show simulation results of the effect of an underground concrete block at shielding the seismic signal coming from an intruder. Based on simulations we found that multiple small arrays can greatly improve the system's detection capability in the presence of underground structures. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

  7. Nanoimprinted nanopillar array chip for procalcitonin detection (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sun, Ling Ling; Zhou, Xiaodong

    2016-03-01

    Procalcitonin (PCT) is an early and highly specific biomarker in response to bacterial infection. The PCT-guided antibiotic therapy has demonstrated to be more efficient than standard therapy to reduce in antibiotic use without adverse outcome in mortality. The PCT detection in clinics is required to be highly sensitive with a sensitivity of 0.5 ng/ml. At present, the technologies for PCT detection are limited. This paper reported a highly sensitive nanoimprinted gold nanopillar array chip for PCT detection. To achieve high sensitivity for PCT detection, the gold nanopillar array sensing chip was designed by plasmonic simulation and fabricated by high fidelity nanoimprinting technology. The gold nanopillars of 140 nm were nanoimprinted on glass substrate. A robust sandwich bioassay of capture antibody /PCT / quantum dot (QD) conjugated detection antibody was established on the gold nanopillar array chip to detect PCT. The nanopillars serve as localized surface plasmon resonance (LSPR) generators to enhance the fluorescent emission from QD. A limit of detection (LOD) of 0.5 ng/ml was achieved for PCT detection. This is the first time that PCT is detected with such high sensitivity by LSPR enhanced QD emission. By considering the low-cost, high sensitivity of the bioassay, as well as the inexpensive mass fabrication of the high quality chips, this novel nanoimprinted gold nanopillar array chip is particularly useful for developing a point-of-care system for PCT detection.

  8. Optical linear algebra processors: noise and error-source modeling.

    PubMed

    Casasent, D; Ghosh, A

    1985-06-01

    The modeling of system and component noise and error sources in optical linear algebra processors (OLAP's) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.

  9. Optical linear algebra processors - Noise and error-source modeling

    NASA Technical Reports Server (NTRS)

    Casasent, D.; Ghosh, A.

    1985-01-01

    The modeling of system and component noise and error sources in optical linear algebra processors (OLAPs) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.

  10. Integrated Seismic Event Detection and Location by Advanced Array Processing

    SciTech Connect

    Kvaerna, T; Gibbons, S J; Ringdal, F; Harris, D B

    2007-02-09

    The principal objective of this two-year study is to develop and test a new advanced, automatic approach to seismic detection/location using array processing. We address a strategy to obtain significantly improved precision in the location of low-magnitude events compared with current fully-automatic approaches, combined with a low false alarm rate. We have developed and evaluated a prototype automatic system which uses as a basis regional array processing with fixed, carefully calibrated, site-specific parameters in conjuction with improved automatic phase onset time estimation. We have in parallel developed tools for Matched Field Processing for optimized detection and source-region identification of seismic signals. This narrow-band procedure aims to mitigate some of the causes of difficulty encountered using the standard array processing system, specifically complicated source-time histories of seismic events and shortcomings in the plane-wave approximation for seismic phase arrivals at regional arrays.

  11. Detection of Fast Transients with Radio Interferometric Arrays

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (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 software. This survey was conducted at 325 and 610 MHz, and covered 360 deg2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  12. DETECTION OF FAST TRANSIENTS WITH RADIO INTERFEROMETRIC ARRAYS

    SciTech Connect

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

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (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 software. This survey was conducted at 325 and 610 MHz, and covered 360 deg{sup 2} of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

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

    SciTech Connect

    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.

  14. Kalman detection of landmines in metal detector array data

    NASA Astrophysics Data System (ADS)

    Abeynayake, Canicious G.; Chant, Ian J.; Nash, Graeme

    2003-09-01

    Tens of millions of mines are currently buried in a number of countries around the world. They cause injuries to civilians and economic damage to war-torn countries by restricting the civilian access to huge agricultural lands. Rapid Route and Area Mine Neutralisation System (RRAMNS) is a Capability Technology Demonstrator (CTD) conducted by Defence Science and Technology Organisation (DSTO) in Australia. The detection system consists of three sensors: a metal detector array, an array of ground penetrating radar (GPR), and forward looking infrared and visual imaging systems. The Kalman filter-based detection technique has previously been shown to be a powerful tool for detection of landmines from metal detector data. In this paper scalar Kalman filter-based detection algorithm has been extended to the multi-dimensional case. The new version of the detection technique has been successfully implemented in RRAMNS real-time mine detection system.

  15. Nanomaterials and biomaterials in electrochemical arrays for protein detection

    PubMed Central

    Rusling, James F.; Bishop, Gregory W.; Doan, Nhi; Papadimitrakopoulos, Fotios

    2013-01-01

    Nanomaterials and biomaterials are important components of new electrochemical arrays designed for sensitive detection of proteins in biological fluids. Such multiplexed protein arrays are predicted to have an important future in personalized medical diagnostics, especially for cancer and heart disease. Sandwich immunoassays for proteins benefit greatly in sensitivity from the use of nanostructured sensor surfaces and multilabeled detection strategies involving nano- or microparticles. In these assays, capture agents such as antibodies or aptamers are attached to sensor surfaces in the array. Target proteins with large binding constants for the affinity agents are captured from liquid samples with high efficiency, either on the sensors or on magnetic bioconjugate particles decorated with many copies of labels and antibodies. After target proteins are captured on the sensor surfaces, the labels are detected by electrochemical techniques. This feature article begins with an overview of the recent history of nanoparticles in electrochemical protein sensors, then moves on to specific examples from our own laboratories. We discuss fabrication of nanostructured sensors and arrays with the aim of multiplexed detection as well as reusability. Following this, we describe systems that integrate particle-based protein sensing with microfluidics for multiplexed protein detection. We end with predictions on the diagnostic future of protein detection. PMID:24392222

  16. Oligonucleotide Array for Identification and Detection of Pythium Species†

    PubMed Central

    Tambong, J. T.; de Cock, A. W. A. M.; Tinker, N. A.; Lévesque, C. A.

    2006-01-01

    A DNA array containing 172 oligonucleotides complementary to specific diagnostic regions of internal transcribed spacers (ITS) of more than 100 species was developed for identification and detection of Pythium species. All of the species studied, with the exception of Pythium ostracodes, exhibited a positive hybridization reaction with at least one corresponding species-specific oligonucleotide. Hybridization patterns were distinct for each species. The array hybridization patterns included cluster-specific oligonucleotides that facilitated the recognition of species, including new ones, belonging to groups such as those producing filamentous or globose sporangia. BLAST analyses against 500 publicly available Pythium sequences in GenBank confirmed that species-specific oligonucleotides were unique to all of the available strains of each species, of which there were numerous economically important ones. GenBank entries of newly described species that are not putative synonyms showed no homology to sequences of the spotted species-specific oligonucleotides, but most new species did match some of the cluster-specific oligonucleotides. Further verification of the specificity of the DNA array was done with 50 additional Pythium isolates obtained by soil dilution plating. The hybridization patterns obtained were consistent with the identification of these isolates based on morphology and ITS sequence analyses. In another blind test, total DNA of the same soil samples was amplified and hybridized on the array, and the results were compared to those of 130 Pythium isolates obtained by soil dilution plating and root baiting. The 13 species detected by the DNA array corresponded to the isolates obtained by a combination of soil dilution plating and baiting, except for one new species that was not represented on the array. We conclude that the reported DNA array is a reliable tool for identification and detection of the majority of Pythium species in environmental samples

  17. Laser diode arrays for expanded mine detection capability

    NASA Astrophysics Data System (ADS)

    Crosby, Frank J.; Holloway, John H., Jr.; Petee, Danny A.; Stetson, Suzanne P.; Suiter, Harold R.; Tinsley, Ken R.

    2002-08-01

    A tactical unmanned aerial vehicle-size illumination system for enhanced mine detection capabilities has been designed, developed, integrated, and tested at the Coastal Systems Station. Airborne test flights were performed from June 12, 2001 to February 1, 2002. The Airborne Laser Diode Array Illuminator uses a single-wavelength compact laser diode array stack to provide illumination and is coupled with a pair of intensified CCD video cameras. The cameras were outfitted with various lenses and polarization filters to determine the benefits of each of the configurations. The first airborne demonstration of a laser diode illumination system is described and its effectiveness to perform nighttime mine detection operations is shown.

  18. DETECTING MASSIVE GRAVITONS USING PULSAR TIMING ARRAYS

    SciTech Connect

    Lee, Kejia; Kramer, Michael; Jenet, Fredrick A.; Price, Richard H.; Wex, Norbert

    2010-10-20

    At the limit of weak static fields, general relativity becomes Newtonian gravity with a potential field that falls off as inverse distance rather than a theory of Yukawa-type fields with a finite range. General relativity also predicts that the speed of disturbances of its waves is c, the vacuum light speed, and is non-dispersive. For these reasons, the graviton, the boson for general relativity, can be considered to be massless. Massive gravitons, however, are features of some alternatives to general relativity. This has motivated experiments and observations that, so far, have been consistent with the zero-mass graviton of general relativity, but further tests will be valuable. A basis for new tests may be the high sensitivity gravitational wave (GW) experiments that are now being performed and the higher sensitivity experiments that are being planned. In these experiments, it should be feasible to detect low levels of dispersion due to non-zero graviton mass. One of the most promising techniques for such a detection may be the pulsar timing program that is sensitive to nano-Hertz GWs. Here, we present some details of such a detection scheme. The pulsar timing response to a GW background with the massive graviton is calculated, and the algorithm to detect the massive graviton is presented. We conclude that, with 90% probability, massless gravitons can be distinguished from gravitons heavier than 3 x 10{sup -22} eV (Compton wavelength {lambda}{sub g} = 4.1 x 10{sup 12} km), if bi-weekly observation of 60 pulsars is performed for 5 years with a pulsar rms timing accuracy of 100 ns. If 60 pulsars are observed for 10 years with the same accuracy, the detectable graviton mass is reduced to 5 x 10{sup -23} eV ({lambda}{sub g} = 2.5 x 10{sup 13} km); for 5 year observations of 100 or 300 pulsars, the sensitivity is respectively 2.5 x 10{sup -22} ({lambda}{sub g} = 5.0 x 10{sup 12} km) and 10{sup -22} eV ({lambda}{sub g} = 1.2 x 10{sup 13} km). Finally, a 10 year

  19. A novel algorithm for automatic arrays detection in a layout

    NASA Astrophysics Data System (ADS)

    Shafee, Marwah; Park, Jea-Woo; Aslyan, Ara; Torres, Andres; Madkour, Kareem; ElManhawy, Wael

    2013-03-01

    Integrated circuits suffer from serious layout printability issues associated to the lithography manufacturing process. Regular layout designs are emerging as alternative solutions to help reducing these systematic sub-wavelength lithography variations. From CAD point of view, regular layouts can be treated as repeated patterns that are arranged in arrays. In most modern mask synthesis and verification tools, cell based hierarchical processing has been able to identify repeating cells by analyzing the design's cell placement; however, there are some routing levels which are not inside the cell and yet they create an array-like structure because of the underlying topologies which could be exploited by detecting repeated patterns in layout thus reducing simulation run-time by simulating only the representing cells and then restore all the simulation results in their corresponding arrays. The challenge is to make the array detection and restoration of the results a very lightweight operation to fully realize the benefits of the approach. A novel methodology for detecting repeated patterns in a layout is proposed. The main idea is based on translating the layout patterns into string of symbols and construct a "Symbolic Layout". By finding repetitions in the symbolic layout, repeated patterns in the drawn layout are detected. A flow for layout reduction based on arrays-detection followed by pattern-matching is discussed. Run time saving comes from doing all litho simulations on the base-patterns only. The pattern matching is then used to restore all the simulation results over the arrays. The proposed flow shows 1.4x to 2x run time enhancement over the regular litho simulation flow. An evaluation for the proposed flow in terms of coverage and run-time is drafted.

  20. Bistatic radar detection of UHECRs at Telescope Array

    NASA Astrophysics Data System (ADS)

    Hanlon, William

    2013-04-01

    The Telescope Array radar (TARA) project will utilize a bistatic radar technique to detect radar echos from the ionization trails of ultra-high energy cosmic rays as they pass through the Earth's atmosphere. It is colocated with the Telescope Array, the largest cosmic ray observatory in the northern hemisphere, which will provide additional confirmation of the detection and properties of UHECRs via time coincidence. This method of observing cosmic rays has been unproven and is the largest and most ambitious attempt yet at UHECR detection utilizing an array of high gain yagi antennas broadcasting 8 MW of effective radiated power over the TA surface detector array. Recently TARA has been field testing a low power version of the experiment to gain expertise and study techniques to better utilize the radar method on a much larger scale. Soon TARA will begin high power operations and will be the first experiment to utilize this technique at such high power in conjunction with such a large cosmic ray detector. I will discuss the physics of UHECR detection via bistatic radar and the design and goals of the TARA project. I will also discuss recent tests of radar echo detection utilizing TA's electron light source which provides in situ small air showers used for TA calibration.

  1. Single-cell chromosomal imbalances detection by array CGH

    PubMed Central

    Le Caignec, Cedric; Spits, Claudia; Sermon, Karen; De Rycke, Martine; Thienpont, Bernard; Debrock, Sophie; Staessen, Catherine; Moreau, Yves; Fryns, Jean-Pierre; Van Steirteghem, Andre; Liebaers, Inge; Vermeesch, Joris R.

    2006-01-01

    Genomic imbalances are a major cause of constitutional and acquired disorders. Therefore, aneuploidy screening has become the cornerstone of preimplantation, prenatal and postnatal genetic diagnosis, as well as a routine aspect of the diagnostic workup of many acquired disorders. Recently, array comparative genomic hybridization (array CGH) has been introduced as a rapid and high-resolution method for the detection of both benign and disease-causing genomic copy-number variations. Until now, array CGH has been performed using a significant quantity of DNA derived from a pool of cells. Here, we present an array CGH method that accurately detects chromosomal imbalances from a single lymphoblast, fibroblast and blastomere within a single day. Trisomy 13, 18, 21 and monosomy X, as well as normal ploidy levels of all other chromosomes, were accurately determined from single fibroblasts. Moreover, we showed that a segmental deletion as small as 34 Mb could be detected. Finally, we demonstrated the possibility to detect aneuploidies in single blastomeres derived from preimplantation embryos. This technique offers new possibilities for genetic analysis of single cells in general and opens the route towards aneuploidy screening and detection of unbalanced translocations in preimplantation embryos in particular. PMID:16698960

  2. Detecting stochastic backgrounds of gravitational waves with pulsar timing arrays

    NASA Astrophysics Data System (ADS)

    Siemens, Xavier

    2016-03-01

    For the past decade the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been using the Green Bank Telescope and the Arecibo Observatory to monitor millisecond pulsars. NANOGrav, along with two other international collaborations, the European Pulsar Timing Array and the Parkes Pulsar Timing Array in Australia, form a consortium of consortia: the International Pulsar Timing Array (IPTA). The goal of the IPTA is to directly detect low-frequency gravitational waves which cause small changes to the times of arrival of radio pulses from millisecond pulsars. In this talk I will discuss the work of NANOGrav and the IPTA, as well as our sensitivity to stochastic backgrounds of gravitational waves. I will show that a detection of the background produced by supermassive black hole binaries is possible by the end of the decade. Supported by the NANOGrav Physics Frontiers Center.

  3. Arrays of dual nanomechanical resonators for selective biological detection.

    PubMed

    Ramos, Daniel; Arroyo-Hernández, María; Gil-Santos, Eduardo; Tong, Hien Duy; Van Rijn, Cees; Calleja, Montserrat; Tamayo, Javier

    2009-03-15

    Arrays of small nanomechanical resonators with dual geometry have been fabricated for sensitive biological detection. The arrays consist of silicon nitride resonating 100 nm thick cantilevers with sensing gold areas alternately placed on the free and fixed cantilever ends. The Au areas act as sensing regions as can be functionalized by means of thiol chemistry. The nanomechanical arrays provide a double flavor of the adsorbed molecules: the added mass reported by the cantilevers with the Au area at the tip and the nanoscale elasticity reported by the cantilevers with the Au area at the clamp. The devices were applied for DNA detection based on Watson-Crick pairing rules. The proposed design for nanomechanical resonators provides higher specificity for DNA sensing in comparison with conventional single cantilevers. The nanoscale elasticity induced by the DNA hybridization arises from the intermolecular interactions between the adsorbates bound to the cantilever and the surface stress.

  4. A colorimetric sensor array for detection of triacetone triperoxide vapor.

    PubMed

    Lin, Hengwei; Suslick, Kenneth S

    2010-11-10

    Triacetone triperoxide (TATP), one of the most dangerous primary explosives, has emerged as an explosive of choice for terrorists in recent years. Owing to the lack of UV absorbance, fluorescence, or facile ionization, TATP is extremely difficult to detect directly. Techniques that are able to detect generally require expensive instrumentation, need extensive sample preparation, or cannot detect TATP in the gas phase. Here we report a simple and highly sensitive colorimetric sensor for the detection of TATP vapor with semiquantitative analysis from 50 ppb to 10 ppm. By using a solid acid catalyst to pretreat a gas stream, we have discovered that a colorimetric sensor array of redox sensitive dyes can detect even very low levels of TATP vapor from its acid decomposition products (e.g., H(2)O(2)) with limits of detection (LOD) below 2 ppb (i.e., <0.02% of its saturation vapor pressure). Common potential interferences (e.g., humidity, personal hygiene products, perfume, laundry supplies, volatile organic compounds, etc.) do not generate an array response, and the array can also differentiate TATP from other chemical oxidants (e.g., hydrogen peroxide, bleach, tert-butylhydroperoxide, peracetic acid).

  5. A colorimetric sensor array for detection of triacetone triperoxide vapor.

    PubMed

    Lin, Hengwei; Suslick, Kenneth S

    2010-11-10

    Triacetone triperoxide (TATP), one of the most dangerous primary explosives, has emerged as an explosive of choice for terrorists in recent years. Owing to the lack of UV absorbance, fluorescence, or facile ionization, TATP is extremely difficult to detect directly. Techniques that are able to detect generally require expensive instrumentation, need extensive sample preparation, or cannot detect TATP in the gas phase. Here we report a simple and highly sensitive colorimetric sensor for the detection of TATP vapor with semiquantitative analysis from 50 ppb to 10 ppm. By using a solid acid catalyst to pretreat a gas stream, we have discovered that a colorimetric sensor array of redox sensitive dyes can detect even very low levels of TATP vapor from its acid decomposition products (e.g., H(2)O(2)) with limits of detection (LOD) below 2 ppb (i.e., <0.02% of its saturation vapor pressure). Common potential interferences (e.g., humidity, personal hygiene products, perfume, laundry supplies, volatile organic compounds, etc.) do not generate an array response, and the array can also differentiate TATP from other chemical oxidants (e.g., hydrogen peroxide, bleach, tert-butylhydroperoxide, peracetic acid). PMID:20949933

  6. Self-assembled nanoparticle arrays for multiphase trace analyte detection

    NASA Astrophysics Data System (ADS)

    Cecchini, Michael P.; Turek, Vladimir A.; Paget, Jack; Kornyshev, Alexei A.; Edel, Joshua B.

    2013-02-01

    Nanoplasmonic structures designed for trace analyte detection using surface-enhanced Raman spectroscopy typically require sophisticated nanofabrication techniques. An alternative to fabricating such substrates is to rely on self-assembly of nanoparticles into close-packed arrays at liquid/liquid or liquid/air interfaces. The density of the arrays can be controlled by modifying the nanoparticle functionality, pH of the solution and salt concentration. Importantly, these arrays are robust, self-healing, reproducible and extremely easy to handle. Here, we report on the use of such platforms formed by Au nanoparticles for the detection of multi-analytes from the aqueous, organic or air phases. The interfacial area of the Au array in our system is ≈25 mm2 and can be made smaller, making this platform ideal for small-volume samples, low concentrations and trace analytes. Importantly, the ease of assembly and rapid detection make this platform ideal for in-the-field sample testing of toxins, explosives, narcotics or other hazardous chemicals.

  7. Nine-analyte detection using an array-based biosensor

    NASA Technical Reports Server (NTRS)

    Taitt, Chris Rowe; Anderson, George P.; Lingerfelt, Brian M.; Feldstein, s. Mark. J.; Ligler, Frances S.

    2002-01-01

    A fluorescence-based multianalyte immunosensor has been developed for simultaneous analysis of multiple samples. While the standard 6 x 6 format of the array sensor has been used to analyze six samples for six different analytes, this same format has the potential to allow a single sample to be tested for 36 different agents. The method described herein demonstrates proof of principle that the number of analytes detectable using a single array can be increased simply by using complementary mixtures of capture and tracer antibodies. Mixtures were optimized to allow detection of closely related analytes without significant cross-reactivity. Following this facile modification of patterning and assay procedures, the following nine targets could be detected in a single 3 x 3 array: Staphylococcal enterotoxin B, ricin, cholera toxin, Bacillus anthracis Sterne, Bacillus globigii, Francisella tularensis LVS, Yersiniapestis F1 antigen, MS2 coliphage, and Salmonella typhimurium. This work maximizes the efficiency and utility of the described array technology, increasing only reagent usage and cost; production and fabrication costs are not affected.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:27479353

  10. Biomimetic MEMS sensor array for navigation and water detection

    NASA Astrophysics Data System (ADS)

    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.

  11. Matrix preconditioning: a robust operation for optical linear algebra processors.

    PubMed

    Ghosh, A; Paparao, P

    1987-07-15

    Analog electrooptical processors are best suited for applications demanding high computational throughput with tolerance for inaccuracies. Matrix preconditioning is one such application. Matrix preconditioning is a preprocessing step for reducing the condition number of a matrix and is used extensively with gradient algorithms for increasing the rate of convergence and improving the accuracy of the solution. In this paper, we describe a simple parallel algorithm for matrix preconditioning, which can be implemented efficiently on a pipelined optical linear algebra processor. From the results of our numerical experiments we show that the efficacy of the preconditioning algorithm is affected very little by the errors of the optical system.

  12. Negative base encoding in optical linear algebra processors

    NASA Technical Reports Server (NTRS)

    Perlee, C.; Casasent, D.

    1986-01-01

    In the digital multiplication by analog convolution algorithm, the bits of two encoded numbers are convolved to form the product of the two numbers in mixed binary representation; this output can be easily converted to binary. Attention is presently given to negative base encoding, treating base -2 initially, and then showing that the negative base system can be readily extended to any radix. In general, negative base encoding in optical linear algebra processors represents a more efficient technique than either sign magnitude or 2's complement encoding, when the additions of digitally encoded products are performed in parallel.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    PubMed

    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. PMID:26564968

  16. Object detection with a multistatic array using singular value decomposition

    DOEpatents

    Hallquist, Aaron T.; Chambers, David H.

    2014-07-01

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across a surface and that travels down the surface. The detection system converts the return signals from a time domain to a frequency domain, resulting in frequency return signals. The detection system then performs a singular value decomposition for each frequency to identify singular values for each frequency. The detection system then detects the presence of a subsurface object based on a comparison of the identified singular values to expected singular values when no subsurface object is present.

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

    PubMed

    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. PMID:22155966

  18. Carbon Nanotube Nanoelectrode Array for Ultrasensitive DNA Detection

    NASA Technical Reports Server (NTRS)

    Li, Jun; Koehne, Jessica; Chen, Hua; Cassell, Alan; Ng, Hou Tee; Fan, Wendy; Ye, Qi; Han, Jie; Meyyappan, M.

    2003-01-01

    A reliable nanoelectrode array based on vertically aligned multi-walled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA detection. Characteristic nanoelectrode behavior is observed using low-density MWNT arrays for measuring both bulk and surface immobilized redox species such as K4Fe(CN)6. The open-end of MWNTs present similar properties as graphite edge-plane electrodes with wide potential window, flexible chemical functionalities, and good biocompatibility. Oligonucleotide probes are selectively functionalized at the open ends cf the nanotube array and specifically hybridized with oligonucleotide targets. The guanine groups are employed as the signal moieties in the electrochemical measurements. Ru(bpy)3(2+) mediator is used to further amplify the guanine oxidation signal. The hybridization of subattomoles of PCR amplified DNA targets is detected electrochemically by combining the MWNT nanoelectrode array with the Ru(bpy)32' amplification mechanism. This system provides a general platform of molecular diagnostics for applications requiring ultrahigh sensitivity, high-degree of miniaturization, and simple sample preparations.

  19. Passive Detection of Narrowband Sources Using a Sensor Array

    SciTech Connect

    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.

  20. Pattern recognition for selective odor detection with gas sensor arrays.

    PubMed

    Kim, Eungyeong; Lee, Seok; Kim, Jae Hun; Kim, Chulki; Byun, Young Tae; Kim, Hyung Seok; Lee, Taikjin

    2012-01-01

    This paper presents a new pattern recognition approach for enhancing the selectivity of gas sensor arrays for clustering intelligent odor detection. The aim of this approach was to accurately classify an odor using pattern recognition in order to enhance the selectivity of gas sensor arrays. This was achieved using an odor monitoring system with a newly developed neural-genetic classification algorithm (NGCA). The system shows the enhancement in the sensitivity of the detected gas. Experiments showed that the proposed NGCA delivered better performance than the previous genetic algorithm (GA) and artificial neural networks (ANN) methods. We also used PCA for data visualization. Our proposed system can enhance the reproducibility, reliability, and selectivity of odor sensor output, so it is expected to be applicable to diverse environmental problems including air pollution, and monitor the air quality of clean-air required buildings such as a kindergartens and hospitals. PMID:23443378

  1. Antibody-based protein detection using piezoresistive cantilever arrays

    NASA Astrophysics Data System (ADS)

    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.

  2. Towards robust gravitational wave detection with pulsar timing arrays

    NASA Astrophysics Data System (ADS)

    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.

  3. Heterodyne detection with mismatch correction base on array detector

    NASA Astrophysics Data System (ADS)

    Hongzhou, Dong; Guoqiang, Li; Ruofu, Yang; Chunping, Yang; Mingwu, Ao

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  4. Non-specific sensor arrays for chemical detection

    NASA Astrophysics Data System (ADS)

    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.

  5. Heterodyne detection with mismatch correction based on array detector

    NASA Astrophysics Data System (ADS)

    Dong, Hongzhou; Li, Guoqiang; Yang, Ruofu; Yang, Chunping; Ao, Mingwu

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  6. Real-time threat detection using magnetometer arrays

    NASA Astrophysics Data System (ADS)

    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.

  7. Vertically aligned carbon nanofiber electrode arrays for nucleic acid detection

    NASA Astrophysics Data System (ADS)

    Arumugam, Prabhu U.; Yu, Edmond; Riviere, Roger; Meyyappan, M.

    2010-10-01

    We present electrochemical detection of DNA targets that corresponds to Escherichia coli O157:H7 16S rRNA gene using a nanoelectrode array consisting of vertically aligned carbon nanofiber (VACNF) electrodes. Parylene C is used as gap filling 'matrix' material to avoid high temperature processing in electrode construction. This easy to deposit film of several micron heights provides a conformal coating between the high aspect ratio VACNFs with negligible pin-holes. The low background currents show the potential of this approach for ultra-sensitive detection. Consistent and reproducible electrochemical-signals are achieved using a simple electrode preparation. This simple, reliable and low-cost approach is a forward step in developing practical sensors for applications like pathogen detection, early cancer diagnosis and environmental monitoring.

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

    PubMed

    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.

  9. Multiplex detection of disease marker proteins with arrayed imaging reflectometry

    NASA Astrophysics Data System (ADS)

    Yadav, Amrita; Sriram, Rashmi; Miller, Benjamin L.

    2010-02-01

    Arrayed Imaging Reflectometry, or "AIR", is a new label-free optical technique for detecting proteins. AIR relies on binding-induced changes in the response of an antireflective coating on the surface of a silicon chip. Thus far, we have demonstrated the use of AIR for the detection of pathogenic E. coli, and for multiplex detection of a broad range of proteins in human serum. Creation of the near-perfect antireflective coating on the surface of silicon requires careful control over preparation of the chip surface prior to probe molecule immobilization. We present methods for highly reproducible, solution-phase silanization and glutaraldehyde functionalization of silicon chips carrying a layer of thermal oxide. Following functionalization with antibodies and passivation of remaining reactive groups, these surfaces provide exceptional performance in the AIR assay.

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

    PubMed

    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. PMID:11669531

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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 (≈ 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.

  13. Wake Vortex Detection: Phased Microphone vs. Linear Infrasonic Array

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A.; Zuckerwar, Allan J.; Sullivan, Nicholas T.; Knight, Howard K.

    2014-01-01

    Sensor technologies can make a significant impact on the detection of aircraft-generated vortices in an air space of interest, typically in the approach or departure corridor. Current state-of-the art sensor technologies do not provide three-dimensional measurements needed for an operational system or even for wake vortex modeling to advance the understanding of vortex behavior. Most wake vortex sensor systems used today have been developed only for research applications and lack the reliability needed for continuous operation. The main challenges for the development of an operational sensor system are reliability, all-weather operation, and spatial coverage. Such a sensor has been sought for a period of last forty years. Acoustic sensors were first proposed and tested by National Oceanic and Atmospheric Administration (NOAA) early in 1970s for tracking wake vortices but these acoustic sensors suffered from high levels of ambient noise. Over a period of the last fifteen years, there has been renewed interest in studying noise generated by aircraft wake vortices, both numerically and experimentally. The German Aerospace Center (DLR) was the first to propose the application of a phased microphone array for the investigation of the noise sources of wake vortices. The concept was first demonstrated at Berlins Airport Schoenefeld in 2000. A second test was conducted in Tarbes, France, in 2002, where phased microphone arrays were applied to study the wake vortex noise of an Airbus 340. Similarly, microphone phased arrays and other opto-acoustic microphones were evaluated in a field test at the Denver International Airport in 2003. For the Tarbes and Denver tests, the wake trajectories of phased microphone arrays and lidar were compared as these were installed side by side. Due to a built-in pressure equalization vent these microphones were not suitable for capturing acoustic noise below 20 Hz. Our group at NASA Langley Research Center developed and installed an

  14. Prion protein detection in serum using micromechanical resonator arrays.

    PubMed

    Varshney, Madhukar; Waggoner, Philip S; Montagna, Richard A; Craighead, Harold G

    2009-12-15

    Prion proteins that have transformed from their normal cellular counterparts (PrP(c)) into infectious form (PrP(res)) are responsible for causing progressive neurodegenerative diseases in numerous species, such as bovine spongiform encephalopathy (BSE) in cattle (also known as mad cow disease), scrapie in sheep, and Creutzfeldt-Jakob disease (CJD) in humans. Due to a possible link between BSE and CJD it is highly desirable to develop non-invasive and ante mortem tests for the detection of prion proteins in bovine samples. Such ante mortem tests of all cows prior to slaughter will help to prevent the introduction of PrP(res) into the human food supply. Furthermore, detection of PrP(res) in donated blood will also help to prevent the transmission of CJD among humans through blood transfusion. In this study, we have continued development of a micromechanical resonator array that is capable of detecting PrP(c) in bovine blood serum. The sensitivity of the resonators for the detection of PrP(c) is further enhanced by the use of secondary mass labels. A pair of antibodies is used in a sandwich immunoassay format to immobilize PrP(c) on the surface of resonators and attach nanoparticles as secondary mass labels to PrP(c). Secondary mass labeling is optimized in terms of incubation time to maximize the frequency shifts that correspond to the presence of PrP(c) on the surface of resonators. Our results show that a minimum of 200 pg mL(-1) of PrP(c) in blood serum can be detected using micromechanical resonator arrays. PMID:19836525

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Interdigitated array microelectrode capacitive sensor for detection of paraffinophilic mycobacteria

    NASA Astrophysics Data System (ADS)

    Sampson, Andrew M.; Peterson, Erik T. K.; Papautsky, Ian

    2008-02-01

    Mycobacterium Avium Complex (MAC) is an opportunistic pathogen that threatens public health and has high clinical relevance. While culture-based and molecular biology techniques for identification are available, these methods are prone to error and require weeks to perform. There is a critical need for improved portable lab-on-a-chip sensor technology which will enable accurate and rapid point-of-care detection of these microorganisms. In this work, a new capacitive sensing strategy is explored utilizing interdigitated array (IDA) microelectrodes and exploiting the paraffinophilic nature of MAC. In this approach, paraffin wax is deposited over IDA microelectrodes to selectively extract these microorganisms from samples. As bacteria consume the dielectric paraffin layer, the charging current of the IDA capacitor changes to facilitate detection. Several IDA geometries were designed and simulated using CFD-ACE+ modeling software and compared with mathematical models. Capacitance of fabricated devices was determined using a charge-based capacitance measurement (CBCM) technique. Modeling and experimental results were in good agreement. Detection of femto-Farad changes in capacitance is possible, making this a feasible technique for sensing small changes in the paraffin for detection of paraffinophilic MAC.

  18. High Density Nano-Electrode Array for Radiation Detection

    SciTech Connect

    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

  19. The Parkes Pulsar Timing Array and detection of gravitational waves

    NASA Astrophysics Data System (ADS)

    Manchester, R.

    Gravitational waves are an important prediction of Einstein s general theory of relativity Evidence for their existence has come from observations of orbit decay in double-neutron-star binary systems but up to now despite huge efforts there has been no direct detection of these waves In collaboration with groups from the Swinburne University of Technology Melbourne and the University of Texas Brownsville we have embarked on a major project to establish the Parkes Pulsar Timing Array PPTA with the principal goal of making a direct detection of gravitational waves of astronomical origin The project involves making precision timing observations of 20 millisecond pulsars at intervals of 2 -- 3 weeks using the Parkes 64-m radio telescope Observations are made at three radio frequencies 685 1400 and 3100 MHz to allow correction for interstellar propagation effects The PPTA is most sensitive to gravitational waves with frequencies in the nanoHertz range and hence is complementary to ground- and space-based laser interferometer systems Simulations suggest that if timing precisions of order 100 nanoseconds can be reached for most of the observed sample over a 5-year data span the stochastic background of gravitational waves from super-massive binary black holes in the cores of galaxies should be detectable Currently we have achieved this level of precision for 3 or 4 pulsars and sub-microsecond precision for a further 8 or 9 pulsars Improved hardware and software systems under development will hopefully allow us to reach our goal The PPTA

  20. Detection of chromosomal imbalances in children with idiopathic mental retardation by array based comparative genomic hybridisation (array-CGH)

    PubMed Central

    Schoumans, J; Ruivenkamp, C; Holmberg, E; Kyllerman, M; Anderlid, B; Nordenskjold, M

    2005-01-01

    Chromosomal aberrations are a common cause of multiple anomaly syndromes that include growth and developmental delay and dysmorphism. Novel high resolution, whole genome technologies, such as array based comparative genomic hybridisation (array-CGH), improve the detection rate of submicroscopic chromosomal abnormalities allowing re-investigation of cases where conventional cytogenetic techniques, Spectral karyotyping (SKY), and FISH failed to detect abnormalities. We performed a high resolution genome-wide screening for submicroscopic chromosomal rearrangements using array-CGH on 41 children with idiopathic mental retardation (MR) and dysmorphic features. The commercially available microarray from Spectral Genomics contained 2600 BAC clones spaced at approximately 1 Mb intervals across the genome. Standard chromosome analysis (>450 bands per haploid genome) revealed no chromosomal rearrangements. In addition, multi-subtelomeric FISH screening in 30 cases and SKY in 11 patients did not detect any abnormality. Using array-CGH we detected chromosomal imbalances in four patients (9.8%) ranging in size from 2 to 14 Mb. Large scale copy number variations were frequently observed. Array-CGH has become an important tool for the detection of chromosome aberrations and has the potential to identify genes involved in developmental delay and dysmorphism. Moreover, the detection of genomic imbalances of clinical significance will increase knowledge of the human genome by performing genotype-phenotype correlation. PMID:16141005

  1. Comparison between BAC and oligo array platforms in detecting submicroscopic genomic rearrangements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Array-based comparative genomic hybridization (array CGH) has emerged as a powerful diagnostic technique for high resolution analysis of the human genome. It is a specific, sensitive, and rapid technique enabling detection of genomic arrangements and copy number changes. A variety of array CGH platf...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. Pathogen detection in milk samples by ligation detection reaction-mediated universal array method.

    PubMed

    Cremonesi, P; Pisoni, G; Severgnini, M; Consolandi, C; Moroni, P; Raschetti, M; Castiglioni, B

    2009-07-01

    This paper describes a new DNA chip, based on the use of a ligation detection reaction coupled to a universal array, developed to detect and analyze, directly from milk samples, microbial pathogens known to cause bovine, ovine, and caprine mastitis or to be responsible for foodborne intoxication or infection, or both. Probes were designed for the identification of 15 different bacterial groups: Staphylococcus aureus, Streptococcus agalactiae, nonaureus staphylococci, Streptococcus bovis, Streptococcus equi, Streptococcus canis, Streptococcus dysgalactiae, Streptococcus parauberis, Streptococcus uberis, Streptococcus pyogenes, Mycoplasma spp., Salmonella spp., Bacillus spp., Campylobacter spp., and Escherichia coli and related species. These groups were identified based on the 16S rRNA gene. For microarray validation, 22 strains from the American Type Culture Collection or other culture collections and 50 milk samples were tested. The results demonstrated high specificity, with sensitivity as low as 6 fmol. Moreover, the ligation detection reaction-universal array assay allowed for the identification of Mycoplasma spp. in a few hours, avoiding the long incubation times of traditional microbiological identification methods. The universal array described here is a versatile tool able to identify milk pathogens efficiently and rapidly. PMID:19528580

  5. Blocking and detection chemistries affect antibody performance on reverse phase protein arrays.

    PubMed

    Ambroz, Kristi L H; Zhang, Yonghong; Schutz-Geschwender, Amy; Olive, D Michael

    2008-06-01

    Antibody specificity is critical for RP protein arrays (RPA). The effects of blocking and detection chemistries on antibody specificity were evaluated for Western blots and RPA. Blocking buffers significantly affected nonspecific banding on Western blots, with corresponding effects on arrays. Tyramide signal amplification (TSA) increased both specific and nonspecific signals on Westerns and arrays, masking the expected gradations in signal intensity. These results suggest that consistent blocking and detection conditions should be used for antibody validation and subsequent RPA experiments. PMID:18563731

  6. Unexploded ordnance detection using imaging giant magnetoresistive (GMR) sensor arrays

    SciTech Connect

    Chaiken, A., LLNL

    1997-05-06

    False positive detections account for a great part of the expense associated with unexploded ordnance (UXO) remediation. Presently fielded systems like pulsed electromagnetic induction systems and cesium-vapor magnetometers are able to distinguish between UXO and other metallic ground clutter only with difficulty. The discovery of giant magnetoresistance (GMR) has led to the development of a new generation of integrated-circuit magnetic sensors that are far more sensitive than previously available room-temperature-operation electronic devices. The small size of GMR sensors makes possible the construction of array detectors that can be used to image the flux emanating from a ferrous object or from a non-ferrous object with eddy currents imposed by an external coil. The purpose of a GMR-based imaging detector would be to allow the operator to easily distinguish between UXO and benign objects (like shrapnel or spent bullets) that litter formerly used defense sites (FUDS). In order to demonstrate the potential of a GMR-based imaging technology, a crude magnetic imaging system has been constructed using commercially available sensors. The ability to roughly determine the outline and disposition of magnetic objects has been demonstrated. Improvements to the system which are necessary to make it into a high-performance UXO detector are outlined.

  7. Deep diode arrays for X-ray detection

    NASA Technical Reports Server (NTRS)

    Zemel, J. N.

    1984-01-01

    Temperature gradient zone melting process was used to form p-n junctions in bulk of high purity silicon wafers. These diodes were patterned to form arrays for X-ray spectrometers. The whole fabrication processes for these X-ray detectors are reviewed in detail. The p-n junctions were evaluated by (1) the dark diode I-V measurements, (2) the diode C sub I - V measurements, and (3) the MOS C-V measurements. The results showed that these junctions were linearly graded in charge distribution with low reverse bias leakage current flowing through them (few nA at -10 volts). The X-ray detection experiments showed that an FWHM of 500 eV was obtained from these diodes with a small bias of just -5 volts (for X-ray source Fe55). A theoretical model was proposed to explain the extra peaks found in the energy spectra and a very interesting point - cross talk effect was pointed out. This might be a solution to the problem of making really high resolution X-ray spectrometers.

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

    PubMed

    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.

  9. Electrochemical Patterning and Detection of DNA Arrays on a Two-Electrode Platform

    PubMed Central

    Furst, Ariel; Landefeld, Sally; Hill, Michael G.; Barton, Jacqueline K.

    2014-01-01

    We report a novel method of DNA array formation that is electrochemically formed and addressed with a two-electrode platform. Electrochemical activation of a copper catalyst, patterned with one electrode, enables precise placement of multiple sequences of DNA onto a second electrode surface. The two-electrode patterning and detection platform allows for both spatial resolution of the patterned DNA array and optimization of detection through DNA-mediated charge transport with electrocatalysis. This two-electrode platform has been used to form arrays that enable differentiation between well-matched and mismatched sequences, the detection of TATA-binding protein, and sequence-selective DNA hybridization. PMID:24328227

  10. Electrochemical patterning and detection of DNA arrays on a two-electrode platform.

    PubMed

    Furst, Ariel; Landefeld, Sally; Hill, Michael G; Barton, Jacqueline K

    2013-12-26

    We report a novel method of DNA array formation that is electrochemically formed and addressed with a two-electrode platform. Electrochemical activation of a copper catalyst, patterned with one electrode, enables precise placement of multiple sequences of DNA onto a second electrode surface. The two-electrode patterning and detection platform allows for both spatial resolution of the patterned DNA array and optimization of detection through DNA-mediated charge transport with electrocatalysis. This two-electrode platform has been used to form arrays that enable differentiation between well-matched and mismatched sequences, the detection of TATA-binding protein, and sequence-selective DNA hybridization. PMID:24328227

  11. An absorption detection approach for multiplexed capillary electrophoresis using a linear photodiode array.

    PubMed

    Gong, X; Yeung, E S

    1999-11-01

    A novel absorption detection method for highly multiplexed capillary electrophoresis is presented for zone electrophoresis and for micellar electrokinetic chromatography. The approach involves the use of a linear photodiode array on which a capillary array is imaged by a camera lens. Either a tungsten lamp or a mercury lamp can be used as the light source such that all common wavelengths for absorption detection are accessible by simply interchanging narrow-band filters. Each capillary spans several diodes in the photodiode array for absorption measurements. Over 100 densely packed capillaries can be monitored by a single photodiode array element with 1024 diodes. The detection limit for rhodamine 6G for each capillary in the multiplexed array is ∼1.8 × 10(-)(8) M injected (S/N = 2). The cross-talk between adjacent capillaries is less than 0.2%. Simultaneous analysis of 96 samples is demonstrated. PMID:21662842

  12. Array-Based Detection of Persistent Organic Pollutants via Cyclodextrin Promoted Energy Transfer

    PubMed Central

    Serio, Nicole; Moyano, Daniel F.; Rotello, Vincent M.; Levine, Mindy

    2015-01-01

    We report herein the selective array-based detection of 30 persistent organic pollutants via cyclodextrin-promoted energy transfer. The use of three fluorophores enabled the development of an array that classified 30 analytes with 100% accuracy and identified unknown analytes with 96% accuracy, as well as identifying 92% of analytes in urine. PMID:26096542

  13. Synthetic Array Heterodyne Detection: Developments within the Caliope CO{sub 2} DIAL Program

    SciTech Connect

    Rehse, S.J.; Strauss, E.M.

    1995-09-01

    A new technique, Synthetic Array Heterodyne Detection, offers a wider field of view and improved signal to noise for coherent DIAL systems by reducing speckle interference. We have implemented a synthetic multi-pixel array using a CO{sub 2} laser on a single element HgCdTe photodiode.

  14. Silicon PIN diode array hybrids for charged particle detection

    SciTech Connect

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

    1988-09-01

    We report on the design of silicon PIN diode array hybrids for use as charged particle detectors. A brief summary of the need for vertex detectors is presented. Circuitry, block diagrams and device specifications are included. 8 refs., 7 figs., 1 tab.

  15. Ultrasensitive molecular absorption detection using metal slot antenna arrays.

    PubMed

    Ahn, Kwang Jun; Bahk, Young-Mi; Kim, Dai-Sik; Kyoung, Jisoo; Rotermund, Fabian

    2015-07-27

    We theoretically study the transmission reduction of light passing through absorptive molecules embedded in a periodic metal slot array in a near infrared wavelength regime. From the analytically solved transmitted light, we present a simple relation given by the attenuation length of light at the resonance wavelength of the slot antennas with respect to the spectral width of the resonant transmission peak. This relation clearly explains that the control of the transmission reduction even with very low absorptive materials is possible. We investigate also the transmission reduction by absorptive molecules in a real metallic slot antenna array on a dielectric substrate and compare the results with finite difference time domain calculations. In numerical calculations, we demonstrate that the same amount of transmission reduction by a bulk absorptive material can be achieved only with one-hundredth thickness of the same material when it is embedded in an optimized Fano-resonant slot antenna array. Our relation presented in this study can contribute to label-free chemical and biological sensing as an efficient design and performance criterion for periodic slot antenna arrays. PMID:26367567

  16. Static corrections for enhanced signal detection at IMS seismic arrays

    NASA Astrophysics Data System (ADS)

    Wilkins, Neil; Wookey, James; Selby, Neil

    2016-04-01

    Seismic monitoring forms an important part of the International Monitoring System (IMS) for verifying the Comprehensive nuclear Test Ban Treaty (CTBT). Analysis of seismic data can be used to discriminate between nuclear explosions and the tens of thousands of natural earthquakes of similar magnitude that occur every year. This is known as "forensic seismology", and techniques include measuring the P-to-S wave amplitude ratio, the body-to-surface wave magnitude ratio (mb/Ms), and source depth. Measurement of these seismic discriminants requires very high signal-to-noise ratio (SNR) data, and this has led to the development and deployment of seismic arrays as part of the IMS. Array processing methodologies such as stacking can be used, but optimum SNR improvement needs an accurate estimate of the arrival time of the particular seismic phase. To enhance the imaging capability of IMS arrays, we aim to develop site-specific static corrections to the arrival time as a function of frequency, slowness and backazimuth. Here, we present initial results for the IMS TORD array in Niger. Vespagrams are calculated for various events using the F-statistic to clearly identify seismic phases and measure their arrival times. Observed arrival times are compared with those predicted by 1D and 3D velocity models, and residuals are calculated for a range of backazimuths and slownesses. Finally, we demonstrate the improvement in signal fidelity provided by these corrections.

  17. Density Detection of Aligned Nanowire Arrays Using Terahertz Time-Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Xiang, Wenfeng; Wang, Xin; Liu, Yuan; Zhang, JiaQi; Zhao, Kun

    2016-07-01

    A rapid technique is necessary to quantitatively detect the density of nanowire (NW) and nanotube arrays in one-dimensional devices which have been identified as useful building blocks for nanoelectronics, optoelectronics, biomedical devices, etc. Terahertz (THz) time-domain spectroscopy was employed in this research to detect the density of aligned Ni NW arrays. The transmitted amplitude of THz peaks and optical thickness of NW arrays was found to be the effective parameters to analyze the density change of NW arrays. Owing to the low multiple scattering and high order of Ni NW arrays, a linear relationship was observed for the transmitted amplitude and optical thickness regarding NW density, respectively. Therefore, THz technique may be used as a promising tool to characterize the density of one-dimensional structures in the large-scale integrated nanodevice fabrication.

  18. Density Detection of Aligned Nanowire Arrays Using Terahertz Time-Domain Spectroscopy.

    PubMed

    Xiang, Wenfeng; Wang, Xin; Liu, Yuan; Zhang, JiaQi; Zhao, Kun

    2016-12-01

    A rapid technique is necessary to quantitatively detect the density of nanowire (NW) and nanotube arrays in one-dimensional devices which have been identified as useful building blocks for nanoelectronics, optoelectronics, biomedical devices, etc. Terahertz (THz) time-domain spectroscopy was employed in this research to detect the density of aligned Ni NW arrays. The transmitted amplitude of THz peaks and optical thickness of NW arrays was found to be the effective parameters to analyze the density change of NW arrays. Owing to the low multiple scattering and high order of Ni NW arrays, a linear relationship was observed for the transmitted amplitude and optical thickness regarding NW density, respectively. Therefore, THz technique may be used as a promising tool to characterize the density of one-dimensional structures in the large-scale integrated nanodevice fabrication.

  19. Density Detection of Aligned Nanowire Arrays Using Terahertz Time-Domain Spectroscopy.

    PubMed

    Xiang, Wenfeng; Wang, Xin; Liu, Yuan; Zhang, JiaQi; Zhao, Kun

    2016-12-01

    A rapid technique is necessary to quantitatively detect the density of nanowire (NW) and nanotube arrays in one-dimensional devices which have been identified as useful building blocks for nanoelectronics, optoelectronics, biomedical devices, etc. Terahertz (THz) time-domain spectroscopy was employed in this research to detect the density of aligned Ni NW arrays. The transmitted amplitude of THz peaks and optical thickness of NW arrays was found to be the effective parameters to analyze the density change of NW arrays. Owing to the low multiple scattering and high order of Ni NW arrays, a linear relationship was observed for the transmitted amplitude and optical thickness regarding NW density, respectively. Therefore, THz technique may be used as a promising tool to characterize the density of one-dimensional structures in the large-scale integrated nanodevice fabrication. PMID:27431495

  20. Precise annealing of focal plane arrays for optical detection

    SciTech Connect

    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.

  1. Accounting for uncertainty in location when detecting point sources using infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Nichols, J. M.; Waterman, J. R.

    2016-07-01

    This work derives the modeling and detection theory required to predict the performance of an infrared focal plane array in detecting point source targets. Specifically, we focus on modeling the uncertainty associated with the location of the point source on the array. In the process we derive several new expressions related to pixel-averaged detection performance under a variety of problem assumptions. The resulting predictions are compared to standard approaches where the location is assumed fixed and known. It is further shown how to incorporate these predictions into multi-frame detection strategies.

  2. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    NASA Astrophysics Data System (ADS)

    Zhao, Chen; Thuo, Martin M.; Liu, Xinyu

    2013-10-01

    Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way.

  3. DETECTING COLD GAS AT z = 3 WITH THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY AND THE SQUARE KILOMETER ARRAY

    SciTech Connect

    Obreschkow, D.; Heywood, I.; Rawlings, S.

    2011-12-10

    We forecast the abilities of the Atacama Large Millimeter/submillimeter Array (ALMA) and the Square Kilometer Array (SKA) to detect CO and H I emission lines in galaxies at redshift z = 3. A particular focus is set on Milky Way (MW) progenitors at z = 3 since their detection within 24 hr constitutes a key science goal of ALMA. The analysis relies on a semi-analytic model, which permits the construction of an MW progenitor sample by backtracking the cosmic history of all simulated present-day galaxies similar to the real MW. Results are as follows: (1) ALMA can best observe an MW at z = 3 by looking at CO(3-2) emission. The probability of detecting a random model MW at 3{sigma} in 24 hr using 75 km s{sup -1} channels is roughly 50%, and these odds can be increased by co-adding the CO(3-2) and CO(4-3) lines. These lines fall into ALMA band 3, which therefore represents the optimal choice toward MW detections at z = 3. (2) Higher CO transitions contained in the ALMA bands {>=}6 will be invisible, unless the considered MW progenitor coincidentally hosts a major starburst or an active black hole. (3) The high-frequency array of SKA, fitted with 28.8 GHz receivers, would be a powerful instrument for observing CO(1-0) at z = 3, able to detect nearly all simulated MWs in 24 hr. (4) H I detections in MWs at z = 3 using the low-frequency array of SKA will be impossible in any reasonable observing time. (5) SKA will nonetheless be a supreme H I survey instrument through its enormous instantaneous field of view (FoV). A one-year pointed H I survey with an assumed FoV of 410 deg{sup 2} would reveal at least 10{sup 5} galaxies at z = 2.95-3.05. (6) If the positions and redshifts of those galaxies are known from an optical/infrared spectroscopic survey, stacking allows the detection of H I at z = 3 in less than 24 hr.

  4. Nanowire sensors and arrays for chemical/biomolecule detection

    NASA Technical Reports Server (NTRS)

    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.

  5. Detection of biological warfare agents with fiber-optic microsphere-based DNA arrays

    NASA Astrophysics Data System (ADS)

    Song, Linan; Walt, David R.

    2005-11-01

    Biological warfare agents (BWAs) pose significant threats to both military forces and civilian populations. The increased concern about bioterrorism has promoted the development of rapid, sensitive, and reliable detection systems to provide an early warning for detecting the release of BWAs. We have developed a high-density DNA array to detect BWAs in real environmental samples with fast response times and high sensitivity. An optical fiber bundle containing approximately 50,000 individual 3.1 μm diameter fibers was chemically etched to yield an array of microwells and used as the substrate for the array. 50-mer single-stranded DNA probes designed to be specific for target BWAs were covalently attached to 3.1-μm microspheres, and the microspheres were distributed into the microwells to form a randomized high-density DNA array. We demonstrated the applicability of this DNA array for the identification of Bacillus thuringiensis kurstaki, a BWA simulant, in real samples. PCR was used to amplify the sequences, introduce fluorescent labels into the target molecules, and provide a second level of specificity. After hybridization of test solutions to the array, analysis was performed by evaluating the specific responses of individual probes on the array.

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

    PubMed

    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. PMID:24388931

  7. Electrochemiluminescence DNA sensor array for multiplex detection of biowarfare agents.

    PubMed

    Spehar-Délèze, Anna-Maria; Gransee, Rainer; Martinez-Montequin, Sergio; Bejarano-Nosas, Diego; Dulay, Samuel; Julich, Sandra; Tomaso, Herbert; O'Sullivan, Ciara K

    2015-09-01

    Development of a fully automated electrochemiluminescence (ECL) DNA assay for multiplex detection of six biowarfare agents is described. Aminated-DNA capture probes were covalently immobilised on activated-carbon electrodes and subsequently hybridised to target strands. Detection was achieved via a sandwich-type assay after Ru(bpy)3(2+)-labelled reporter probes were hybridised to the formed probe-target complexes. The assay was performed in an automated microsystem in a custom designed ECL detection box with integrated fluidics, electronics,and movable photomultiplier detector. The obtained limits of detection were 0.6-1.2 nmol L(-1) for six targets ranging from 50 to 122 base pairs in size, with linear range 1-15 nmol L(-1). Non-specific adsorption and cross-reactivity were very low. Detection of six targets on a single chip was achieved with subnanomolar detection limits. PMID:26100549

  8. Space and frequency-multiplexed optical linear algebra processor - Fabrication and initial tests

    NASA Technical Reports Server (NTRS)

    Casasent, D.; Jackson, J.

    1986-01-01

    A new optical linear algebra processor architecture is described. Space and frequency-multiplexing are used to accommodate bipolar and complex-valued data. A fabricated laboratory version of this processor is described, the electronic support system used is discussed, and initial test data obtained on it are presented.

  9. Detecting Changes of a Distant Gas Source with an Array of MOX Gas Sensors

    PubMed Central

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

    2012-01-01

    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. PMID:23443385

  10. Telescope Array measurement of UHECR composition from stereoscopic fluorescence detection

    NASA Astrophysics Data System (ADS)

    Stroman, Thomas; Bergman, Douglas; Abu Zayyad, Tareq

    2014-03-01

    The chemical composition of ultra-high-energy cosmic rays (UHECRs) is an important constraint on models of UHECR production and propagation, and must be determined experimentally. A UHECR-induced extensive air shower's longitudinal development is dictated by the energy per nucleon of the primary particle. The observed distribution of atmospheric slant depths (Xmax) is therefore sensitive to the composition, facilitating measurement of the relative abundances of ``light'' (proton-like) and ``heavy'' (iron-like) primary UHECR particles. The Telescope Array (TA) experiment, the northern hemisphere's largest UHECR detector, includes three fluorescence detector (FD) stations that record the longitudinal development of the extensive air showers produced by UHECR arrivals. ``Stereo'' observation of individual showers by multiple FDs tightly constrains the trajectory reconstruction, allowing a precise measurement of Xmax as well as energy. We will present the stereo TA data from six years of operation and progress toward a measurement of chemical composition.

  11. Selective vapor detection of an integrated chemical sensor array

    NASA Astrophysics Data System (ADS)

    Jung, Youngmo; Kim, Young Jun; Choi, Jaebin; Lim, Chaehyun; Shin, Beom Ju; Moon, Hi Gyu; Lee, Taikjin; Kim, Jae Hun; Seo, Minah; Kang, Chong Yun; Jun, Seong Chan; Lee, Seok; Kim, Chulki

    2015-07-01

    Graphene is a promising material for vapor sensor applications because of its potential to be functionalized for specific chemical gases. In this work, we present a graphene gas sensor that uses single-stranded DNA (ssDNA) molecules as its sensing agent. We investigate the characteristics of graphene field effect transistors (FETs) coated with different ssDNAs. The sensitivity and recovery rate for a specific gas are modified according to the differences in the DNA molecules' Guanine (G) and Cytosine (C) content. ssDNA-functionalized devices show a higher recovery rate compared to bare graphene devices. Pattern analysis of a 2-by-2 sensor array composed of graphene devices functionalized with different-sequence ssDNA enables identification of NH3, NO2, CO, SO2 using Principle Component Analysis (PCA).

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

    PubMed

    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.

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

    PubMed Central

    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

  14. Detection of Multiple Waterborne Pathogens Using Microsequencing Arrays

    EPA Science Inventory

    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...

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

    SciTech Connect

    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.

  16. Fiber-optic microsphere-based arrays for multiplexed biological warfare agent detection.

    PubMed

    Song, Linan; Ahn, Soohyoun; Walt, David R

    2006-02-15

    We report a multiplexed high-density DNA array capable of rapid, sensitive, and reliable identification of potential biological warfare agents. An optical fiber bundle containing 6000 individual 3.1-mum-diameter fibers was chemically etched to yield microwells and used as the substrate for the array. Eighteen different 50-mer single-stranded DNA probes were covalently attached to 3.1-mum microspheres. Probe sequences were designed for Bacillus anthracis, Yersinia pestis, Francisella tularensis, Brucella melitensis, Clostridium botulinum, Vaccinia virus, and one biological warfare agent (BWA) simulant, Bacillus thuringiensis kurstaki. The microspheres were distributed into the microwells to form a randomized multiplexed high-density DNA array. A detection limit of 10 fM in a 50-microL sample volume was achieved within 30 min of hybridization for B. anthracis, Y. pestis, Vaccinia virus, and B. thuringiensis kurstaki. We used both specific responses of probes upon hybridization to complementary targets as well as response patterns of the multiplexed array to identify BWAs with high accuracy. We demonstrated the application of this multiplexed high-density DNA array for parallel identification of target BWAs in spiked sewage samples after PCR amplification. The array's miniaturized feature size, fabrication flexibility, reusability, and high reproducibility may enable this array platform to be integrated into a highly sensitive, specific, and reliable portable instrument for in situ BWA detection.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Diego, Cristina; Hernández, Álvaro; Jiménez, Ana; Álvarez, 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. PMID:22247675

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

    DOEpatents

    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.

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

    PubMed

    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.

  1. Detection of Clinically Relevant Exonic Copy-Number Changes by Array CGH

    PubMed Central

    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.; Gaudio, Daniela del; 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

    2011-01-01

    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. PMID:20848651

  2. Single mode fiber array for planet detection using a visible nulling interferometer

    NASA Technical Reports Server (NTRS)

    Liu, Duncan; Levine, B. Martin; Shao, Michael; Aguayo, Franciso

    2005-01-01

    We report the design, fabrication, and testing of a coherent large mode field diameter fiber array to be used as a spatial filter in a planet finding visible nulling interferometer. The array is a key component of a space instrument for visible-light detection and spectroscopy of Earth like extrasolar planets. In this concept, a nulling interferometer is synthesized from a pupil image of a single aperture which is then spatially filtered by a coherent array of single mode fibers to suppress the residual scattered star light. The use of the fiber array preserves spatial information between the star and planet. The fiber array uses a custom commercial large mode field or low NA step-index single mode fiber to relax alignment tolerances. A matching custom micro lens array is used to couple light into the fibers, and to recollimate the light out of the fiber array. The use of large mode field diameter fiber makes the fabrication of a large spatial filter array with 300 to 1000 elements feasible.

  3. Development of immune-affinity 96 spots monolith array for multiple mycotoxins detection in food samples.

    PubMed

    Li, Li; Xia, Li-Ru; Zhao, Yong-Fu; Wang, He-Ye

    2016-09-01

    In this paper, a novel highly sensitive chemiluminescence immune-affinity 96 spots monolith array was developed to detect deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin (T-2), and fumonisin B1 (FB1) in corn samples. Firstly, the monolith array was prepared through on suit UV-initiated copolymerization using polyethylene glycol diacrylate (PEGDA) as cross-linker, glycidyl methacrylate (GMA) as functional monomer and polyethylene glycol 200 (PEG 200) as the porogen. Subsequently, the four mycotoxins immune-affinity monolith array was prepared by immobilization of DON, ZEN, T-2, and FB1 antibody. The mole ratio of PEGDA/GMA, UV exposure time, and the volume ratio of PEG 200/PEGDA were optimized to improve the performances of the immune-affinity monolith array. For the mycotoxins immune-affinity monolith array based on chemiluminescence detection, the limit of detection was 0.0036ng/mL (DON), 0.0048ng/mL (ZEN), 0.0039ng/mL (T-2), and 0.0017ng/mL (FB1), respectively. The linear response in the range of 0.01-0.1ng/mL (R(2)=0.98). The results showed that the proposed four mycotoxins immune-affinity monolith array was a stable, accurate, and highly sensitive method to determine levels of DON, ZEN, T-2, and FB1 in real samples. PMID:27423670

  4. Development of immune-affinity 96 spots monolith array for multiple mycotoxins detection in food samples.

    PubMed

    Li, Li; Xia, Li-Ru; Zhao, Yong-Fu; Wang, He-Ye

    2016-09-01

    In this paper, a novel highly sensitive chemiluminescence immune-affinity 96 spots monolith array was developed to detect deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin (T-2), and fumonisin B1 (FB1) in corn samples. Firstly, the monolith array was prepared through on suit UV-initiated copolymerization using polyethylene glycol diacrylate (PEGDA) as cross-linker, glycidyl methacrylate (GMA) as functional monomer and polyethylene glycol 200 (PEG 200) as the porogen. Subsequently, the four mycotoxins immune-affinity monolith array was prepared by immobilization of DON, ZEN, T-2, and FB1 antibody. The mole ratio of PEGDA/GMA, UV exposure time, and the volume ratio of PEG 200/PEGDA were optimized to improve the performances of the immune-affinity monolith array. For the mycotoxins immune-affinity monolith array based on chemiluminescence detection, the limit of detection was 0.0036ng/mL (DON), 0.0048ng/mL (ZEN), 0.0039ng/mL (T-2), and 0.0017ng/mL (FB1), respectively. The linear response in the range of 0.01-0.1ng/mL (R(2)=0.98). The results showed that the proposed four mycotoxins immune-affinity monolith array was a stable, accurate, and highly sensitive method to determine levels of DON, ZEN, T-2, and FB1 in real samples.

  5. TNT detection using multiplexed liquid array displacement immunoassays.

    PubMed

    Anderson, George P; Moreira, Solimar C; Charles, Paul T; Medintz, Igor L; Goldman, Ellen R; Zeinali, Mazyar; Taitt, Chris R

    2006-04-01

    The presence of trace contamination of soil and groundwater with explosives is an ongoing concern, for which improved methods are required to facilitate their detection and quantification. This is true both for the monitoring of remediation and for site characterization. Immunosensors have been found effective for solution-phase detection of environmental contaminants. Our work utilized the Luminex100 (flow cytometer) to detect TNT in a multiplexed displacement immunoassay format. The Luminex100 can perform a multiplexed assay by discriminating between up to 100 different bead sets. We used this capability to evaluate four different TNT monoclonal antibodies, two recombinant TNT antibodies, and a control antibody simultaneously for the rapid detection of TNT and other nitroaromatics. TNT could be detected at 0.1 ppb and quantified over the range of 1.0 ppb to 10 ppm. In addition, the assay was shown to be effective in various matrixes such as lake water, seawater, and acetone extracts of soil. Seawater required dilution with two parts buffer to avoid loss of microspheres, while the acetone extracts were diluted 100-fold or more to minimize solvent affects.

  6. Simultaneous detection of three lily-infecting viruses using a multiplex Luminex bead array.

    PubMed

    Lim, Mi Sang; Kim, Su Min; Choi, Sun Hee

    2016-05-01

    A Luminex bead array was applied to detect multiple-virus coinfection in lily plants exhibiting typical symptoms, and the efficiency of this detection system was assessed. Specific primer sets for the simultaneous detection of 4 targets in virus-infected lily plants were constructed and used for reverse transcription (RT)-polymerase chain reaction (PCR), and specific probes were used for Luminex-based assay. Each of the 4 targets was amplified, and the amplicons were used for Luminex bead array experiments. A Luminex bead array analysis of lily-infecting viruses was performed using the quadruplex RT-PCR products followed by hybridization between the biotinylated targets and anti-tagged microsphere beads. The hybridization products produced fluorescence signals that were detected by the Luminex system. Signal strengths were analyzed by their median fluorescence intensity (MFI) values. Detection of the different target elements was found to be very specific to the corresponding viruses in lilies, and coinfection with multiple viruses was specifically detected via the MFI signals. Therefore, the use of a Luminex bead array for the detection of co-infected multiple viruses in lily plants can be an improved system for screening and analyzing multiple-virus infection.

  7. DETECTION, LOCALIZATION, AND CHARACTERIZATION OF GRAVITATIONAL WAVE BURSTS IN A PULSAR TIMING ARRAY

    SciTech Connect

    Finn, Lee Samuel; Lommen, Andrea N.

    2010-08-01

    Efforts to detect gravitational waves by timing an array of pulsars have traditionally focused on stationary gravitational waves, e.g., stochastic or periodic signals. Gravitational wave bursts-signals whose duration is much shorter than the observation period-will also arise in the pulsar timing array waveband. Sources that give rise to detectable bursts include the formation or coalescence of supermassive black holes (SMBHs), the periapsis passage of compact objects in highly elliptic or unbound orbits about an SMBH, or cusps on cosmic strings. Here, we describe how pulsar timing array data may be analyzed to detect and characterize these bursts. Our analysis addresses, in a mutually consistent manner, a hierarchy of three questions. (1) What are the odds that a data set includes the signal from a gravitational wave burst? (2) Assuming the presence of a burst, what is the direction to its source? (3) Assuming the burst propagation direction, what is the burst waveform's time dependence in each of its polarization states? Applying our analysis to synthetic data sets, we find that we can detect gravitational waves even when the radiation is too weak to either localize the source or infer the waveform, and detect and localize sources even when the radiation amplitude is too weak to permit the waveform to be determined. While the context of our discussion is gravitational wave detection via pulsar timing arrays, the analysis itself is directly applicable to gravitational wave detection using either ground- or space-based detector data.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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).

  12. A dual mode imaging array for damage detection in grout structures

    NASA Astrophysics Data System (ADS)

    Tian, Zhenhua; Yu, Lingyu; EL-Batanouny, Mohamed; Ziehl, Paul; Zhao, Liuxian

    2013-04-01

    Due to the heterogeneous nature of the cement-based materials, the ultrasonic waves in concrete exhibit highly scattering and attenuation, leading to the difficulty of concrete damaged detection. This paper presents a dual mode ultrasonic array imaging methodology that can map damage using Rayleigh surface waves and permanently installed piezoelectric sensors. The dual mode sensing integrates passive acoustic emission and active ultrasonic wave inspection. When a crack is developing, acoustic emission (AE) occurs and the disturbance can propagate outwards along the structure surface. A novel AE source imaging algorithm has been developed to detect and locate the AE source. Once the AE source is located, the sensor array switches to its active mode. For active sensing, one sensor in the array is used to generate Rayleigh wave for interrogation, while all the others are used as the wave receivers. All the sensory data are processed by the active ultrasonic array imaging algorithm. The proof-of-concept testing was performed on a grout specimen with representative dimensions. The passive array imaging algorithm was able to locate the AE source simulated by pencil lead break while active sensing imaging was able to detect the damage simulated by a hole. The duel mode imaging method is promising and economically beneficial for solving a key source localization problem in damage detection on large concrete structures.

  13. Spherical porphyrin sensor array based on encoded colloidal crystal beads for VOC vapor detection.

    PubMed

    Xu, Hua; Cao, Kai-Di; Ding, Hai-Bo; Zhong, Qi-Feng; Gu, Hong-Cheng; Xie, Zhuo-Ying; Zhao, Yuan-Jin; Gu, Zhong-Ze

    2012-12-01

    A spherical porphyrin sensor array using colloidal crystal beads (CCBs) as the encoding microcarriers has been developed for VOC vapor detection. Six different porphyrins were coated onto the CCBs with distinctive encoded reflection peaks via physical adsorption and the sensor array was fabricated by placing the prepared porphyrin-modified CCBs together. The change in fluorescence color of the porphyrin-modified CCBs array serves as the detection signal for discriminating between different VOC vapors and the reflection peak of the CCBs serves as the encoding signal to distinguish between different sensors. It was demonstrated that the VOC vapors detection using the prepared sensor array showed excellent discrimination: not only could the compounds from the different chemical classes be easily differentiated (e.g., alcohol vs acids vs ketones) but similar compounds from the same chemical family (e.g., methanol vs ethanol) and the same compound with different concentration ((e.g., Sat. ethanol vs 60 ppm ethanol vs 10 ppm ethanol) could also be distinguished. The detection reproducibility and the humidity effect were also investigated. The present spherical sensor array, with its simple preparation, rapid response, high sensitivity, reproducibility, and humidity insensitivity, and especially with stable and high-throughput encoding, is promising for real applications in artificial olfactory systems. PMID:23163575

  14. Detecting large copy number variants using exome genotyping arrays in a large Swedish schizophrenia sample.

    PubMed

    Szatkiewicz, J P; Neale, B M; O'Dushlaine, C; Fromer, M; Goldstein, J I; Moran, J L; Chambert, K; Kähler, A; Magnusson, P K E; Hultman, C M; Sklar, P; Purcell, S; McCarroll, S A; Sullivan, P F

    2013-11-01

    Although copy number variants (CNVs) are important in genomic medicine, CNVs have not been systematically assessed for many complex traits. Several large rare CNVs increase risk for schizophrenia (SCZ) and autism and often demonstrate pleiotropic effects; however, their frequencies in the general population and other complex traits are unknown. Genotyping large numbers of samples is essential for progress. Large cohorts from many different diseases are being genotyped using exome-focused arrays designed to detect uncommon or rare protein-altering sequence variation. Although these arrays were not designed for CNV detection, the hybridization intensity data generated in each experiment could, in principle, be used for gene-focused CNV analysis. Our goal was to evaluate the extent to which CNVs can be detected using data from one particular exome array (the Illumina Human Exome Bead Chip). We genotyped 9100 Swedish subjects (3962 cases with SCZ and 5138 controls) using both standard genome-wide association study (GWAS) and exome arrays. In comparison with CNVs detected using GWAS arrays, we observed high sensitivity and specificity for detecting genic CNVs 400 kb including known pathogenic CNVs along with replicating the literature finding that cases with SCZ had greater enrichment for genic CNVs. Our data confirm the association of SCZ with 16p11.2 duplications and 22q11.2 deletions, and suggest a novel association with deletions at 11q12.2. Our results suggest the utility of exome-focused arrays in surveying large genic CNVs in very large samples; and thereby open the door for new opportunities such as conducting well-powered CNV assessment and comparisons between different diseases. The use of a single platform also minimizes potential confounding factors that could impact accurate detection. PMID:23938935

  15. An impulse radar array for detecting land mines

    SciTech Connect

    Gavel, D.T.; Mast, J.E.; Warhus, J.; Azevedo, S.G.

    1995-04-03

    The Lawrence Livermore National Laboratory has developed radar and imaging technologies with potential application in demining efforts. A patented wideband (impulse) radar that is very compact, very low cost, and very low power, has been demonstrated in test fields to be able to detect and image nonmetallic land mines buried in 2-10 cm of soil. The scheme takes advantage of the very short radar impulses and the ability to form a large synthetic aperture with many small individual units, to generate high resolution 2-D or 3-D tomographic images of the mine and surrounding ground. Radar range calculations predict that a vehicle-mounted or man-carried system is quite feasible using this technology. This paper presents the results of field tests using a prototype unit and describes practical mine detection system concepts. Predicted capabilities in terms of stand-off range and radiated power requirements are discussed.

  16. Ultra-wide sensor arcs for low frequency sonar detection with a baffled cylindrical array.

    PubMed

    Bertilone, Derek C; Bao, Chaoying; Travaglione, Ben C; Killeen, Damien S

    2009-11-01

    Passive detection with a baffled cylindrical array can potentially be improved at low frequencies by exploiting signal diffraction around the baffle. A model based on infinite rigid cylinder scattering suggests that large gains in signal-to-noise ratio are potentially available to adaptive beamformers if the sensor arc is widened to include sensors in the acoustic shadow. However, elastic scatter effects become increasingly important as frequency decreases, so the gains obtained in practice are unknown. The gains in detection performance are examined in this letter by analyzing data recorded at sea from a platform-mounted sonar array.

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

    PubMed Central

    Shih, Jeanne-Louise; Wu, Kuo-Ting; Jen, Cheng-Kuei; Chiu, Chun-Hsiung; Tzeng, Jing-Chi; Liaw, Jiunn-Woei

    2013-01-01

    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 ϕ3 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. PMID:23322101

  18. Referencing cross-reactivity of detection antibodies for protein array experiments

    PubMed Central

    Lemass, Darragh; O'Kennedy, Richard; Kijanka, Gregor S.

    2016-01-01

    Protein arrays are frequently used to profile antibody repertoires in humans and animals. High-throughput protein array characterisation of complex antibody repertoires requires a platform-dependent, lot-to-lot validation of secondary detection antibodies. This article details the validation of an affinity-isolated anti-chicken IgY antibody produced in rabbit and a goat anti-rabbit IgG antibody conjugated with alkaline phosphatase using protein arrays consisting of 7,390 distinct human proteins. Probing protein arrays with secondary antibodies in absence of chicken serum revealed non-specific binding to 61 distinct human proteins. The cross-reactivity of the tested secondary detection antibodies points towards the necessity of platform-specific antibody characterisation studies for all secondary immunoreagents. Secondary antibody characterisation using protein arrays enables generation of reference lists of cross-reactive proteins, which can be then excluded from analysis in follow-up experiments. Furthermore, making such cross-reactivity lists accessible to the wider research community may help to interpret data generated by the same antibodies in applications not related to protein arrays such as immunoprecipitation, Western blots or other immunoassays. PMID:27335636

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

    DOEpatents

    Lewis, Nathan S.; Freund, Michael S.; Briglin, Shawn S.; Tokumaru, Phillip; Martin, Charles R.; Mitchell, David

    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.

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

    DOEpatents

    Lewis, Nathan S.; Freund, Michael S.; Briglin, Shawn M.; Tokumaru, Phil; Martin, Charles R.; Mitchell, David T.

    2006-10-17

    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.

  1. Nanopore arrays in a silicon membrane for parallel single-molecule detection: DNA translocation.

    PubMed

    Zhang, Miao; Schmidt, Torsten; Jemt, Anders; Sahlén, Pelin; Sychugov, Ilya; Lundeberg, Joakim; Linnros, Jan

    2015-08-01

    Optical nanopore sensing offers great potential in single-molecule detection, genotyping, or DNA sequencing for high-throughput applications. However, one of the bottle-necks for fluorophore-based biomolecule sensing is the lack of an optically optimized membrane with a large array of nanopores, which has large pore-to-pore distance, small variation in pore size and low background photoluminescence (PL). Here, we demonstrate parallel detection of single-fluorophore-labeled DNA strands (450 bps) translocating through an array of silicon nanopores that fulfills the above-mentioned requirements for optical sensing. The nanopore array was fabricated using electron beam lithography and anisotropic etching followed by electrochemical etching resulting in pore diameters down to ∼7 nm. The DNA translocation measurements were performed in a conventional wide-field microscope tailored for effective background PL control. The individual nanopore diameter was found to have a substantial effect on the translocation velocity, where smaller openings slow the translocation enough for the event to be clearly detectable in the fluorescence. Our results demonstrate that a uniform silicon nanopore array combined with wide-field optical detection is a promising alternative with which to realize massively-parallel single-molecule detection. PMID:26180050

  2. Nanopore arrays in a silicon membrane for parallel single-molecule detection: DNA translocation

    NASA Astrophysics Data System (ADS)

    Zhang, Miao; Schmidt, Torsten; Jemt, Anders; Sahlén, Pelin; Sychugov, Ilya; Lundeberg, Joakim; Linnros, Jan

    2015-08-01

    Optical nanopore sensing offers great potential in single-molecule detection, genotyping, or DNA sequencing for high-throughput applications. However, one of the bottle-necks for fluorophore-based biomolecule sensing is the lack of an optically optimized membrane with a large array of nanopores, which has large pore-to-pore distance, small variation in pore size and low background photoluminescence (PL). Here, we demonstrate parallel detection of single-fluorophore-labeled DNA strands (450 bps) translocating through an array of silicon nanopores that fulfills the above-mentioned requirements for optical sensing. The nanopore array was fabricated using electron beam lithography and anisotropic etching followed by electrochemical etching resulting in pore diameters down to ∼7 nm. The DNA translocation measurements were performed in a conventional wide-field microscope tailored for effective background PL control. The individual nanopore diameter was found to have a substantial effect on the translocation velocity, where smaller openings slow the translocation enough for the event to be clearly detectable in the fluorescence. Our results demonstrate that a uniform silicon nanopore array combined with wide-field optical detection is a promising alternative with which to realize massively-parallel single-molecule detection.

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

    PubMed

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

    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 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. PMID:27571080

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

    PubMed Central

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

    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 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. PMID:27571080

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    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 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.

  7. Highly Sensitive Multi-Channel IDC Sensor Array for Low Concentration Taste Detection.

    PubMed

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2015-06-05

    In this study, we designed and developed an interdigitated capacitor (IDC)-based taste sensor array to detect different taste substances. The designed taste sensing array has four IDC sensing elements. The four IDC taste sensing elements of the array are fabricated by incorporating four different types of lipids into the polymer, dioctyl phenylphosphonate (DOPP) and tetrahydrofuran (THF) to make the respective dielectric materials that are individually placed onto an interdigitated electrode (IDE) via spin coating. When the dielectric material of an IDC sensing element comes into contact with a taste substance, its dielectric properties change with the capacitance of the IDC sensing element; this, in turn, changes the voltage across the IDC, as well as the output voltage of each channel of the system. In order to assess the effectiveness of the sensing system, four taste substances, namely sourness (HCl), saltiness (NaCl), sweetness (glucose) and bitterness (quinine-HCl), were tested. The IDC taste sensor array had rapid response and recovery times of about 12.9 s and 13.39 s, respectively, with highly stable response properties. The response property of the proposed IDC taste sensor array was linear, and its correlation coefficient R2 was about 0.9958 over the dynamic range of the taste sensor array as the taste substance concentration was varied from 1 μM to 1 M. The proposed IDC taste sensor array has several other advantages, such as real-time monitoring capabilities, high sensitivity 45.78 mV/decade, good reproducibility with a standard deviation of about 0.029 and compactness, and the circuitry is based on readily available and inexpensive electronic components. The proposed IDC taste sensor array was compared with the potentiometric taste sensor with respect to sensitivity, dynamic range width, linearity and response time. We found that the proposed IDC sensor array has better performance. Finally, principal component analysis (PCA) was applied to

  8. Tropical cyclone waves detected with infrasound sensor array

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-02-01

    The strong winds of a tropical cyclone whip up the sea surface, driving ocean waves a dozen meters high. When one such ocean wave runs into another wave that has an equal period but is traveling in the opposite direction, the interaction produces low-frequency sound waves that can be detected thousands of kilometers away. The infrasound signals produced by interacting ocean surface waves—known as microbarom—have typical frequencies around 0.2 hertz. Researchers previously determined that as a hurricane travels along its track, early waves generated by the storm will interact with those generated later on, producing a strong microbarom signal in the storm's wake. Researchers also found, however, that microbarom signals are produced by regular surface ocean behavior, including swell, surface waves, and nontropical cyclone storms.

  9. Capillary array electrophoresis using laser-excited confocal fluorescence detection

    SciTech Connect

    Huang, X.C.; Quesada, M.A.; Mathies, R.A.

    1992-04-15

    Capillary electrophoresis (CE) has found widespread application in analytical and biomedical research, and the scope and sophistication of CE is still rapidly advancing. Gel-filled capillaries have been employed for the rapid separation and analysis of synthetic polynucleotides, DNA sequencing fragments, and DNA restriction fragments. Open-tube capillary electrophoresis has attained subattomole detection levels in amino acid separations 14 and proven its utility for the separation of proteins, viruses, and bacteria. Separation of the optical isomers of dansyl amino acids has also been successfully demonstrated. Micellar electrokinetic capillary chromatography, isoelectric focusing, and on-column derivatization can all be performed on CE columns, demonstrating the utility of capillary electrophoresis as an analytical and micropreparative tool. 29 refs., 6 figs., 1 tab.

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

    PubMed Central

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

    2012-01-01

    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. PMID:22737009

  11. The Unique Capabilities of the Allen Telescope Array for Pulsar Timing and Gravitational Wave Detection

    NASA Astrophysics Data System (ADS)

    McLaughlin, Maura

    2011-01-01

    Since their discovery in 1982, millisecond pulsars have served as exquisite probes of fundamental physics. I will discuss the most transformative current application of millisecond pulsars: the direct detection of gravitational waves. Timing an array of pulsars could result in the detection of a stochastic background of gravitational waves, most likely resulting from an ensemble of supermassive black hole binaries. The unique capabilities of the Allen Telescope Array (ATA) will make it a very important resource for this experiment. The multi-wavelength coverage will increase sensitivity and enable optimal removal of interstellar propagation affects and the flexibility of scheduling afforded by commensal observing will increase the number of sources times and the cadence at which we can observe each source. I will discuss how these properties complement existing facilities and how including the ATA will increase the sensitivity of the international pulsar timing array.

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

    NASA Astrophysics Data System (ADS)

    Rostgaard, Katrine R.; Frederiksen, Rune S.; Liu, Yi-Chi C.; Berthing, Trine; Madsen, Morten H.; Holm, Johannes; Nygård, Jesper; Martinez, Karen L.

    2013-10-01

    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 solutions. Here we show that vertical arrays of nanowires (NWs) can overcome several bottlenecks of using nanoarrays for extraction and analysis of proteins. The high aspect ratio of the NWs results in a large surface area available for protein immobilization and renders passivation of the surface between 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 to many high aspect ratio nanostructures.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 solutions. Here we show that vertical arrays of nanowires (NWs) can overcome several bottlenecks of using nanoarrays for extraction and analysis of proteins. The high aspect ratio of the NWs results in a large surface area available for protein immobilization and renders passivation of the surface between the NWs unnecessary. Fluorescence detection of proteins allows quantitative measurements and spatial resolution, enabling us to track individual

  13. Periodically porous top electrodes on vertical nanowire arrays for highly sensitive gas detection.

    PubMed

    In, Hyun Jin; Field, Christopher R; Pehrsson, Pehr E

    2011-09-01

    Nanowires of various materials and configurations have been shown to be highly effective in the detection of chemical and biological species. In this paper, we report a novel, nanosphere-enabled approach to fabricating highly sensitive gas sensors based on ordered arrays of vertically aligned silicon nanowires topped with a periodically porous top electrode. The vertical array configuration helps to greatly increase the sensitivity of the sensor while the pores in the top electrode layer significantly improve sensing response times by allowing analyte gases to pass through freely. Herein, we show highly sensitive detection to both nitrogen dioxide (NO(2)) and ammonia (NH(3)) in humidified air. NO(2) detection down to 10 parts per billion (ppb) is demonstrated and an order-of-magnitude improvement in sensor response time is shown in the detection of NH(3).

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

    SciTech Connect

    Ghenuche, Petru; Torres, Juan de; Ferrand, Patrick; Wenger, Jérôme

    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.

  15. Carbon Nanotube Nanoelectrode Array as an Electronic Chip for Ultrasensitive Label-free DNA Detection

    NASA Technical Reports Server (NTRS)

    Li, Jun; Koehne, Jessica; Chen, Hua; Cassell, Alan; Ng, Hou Tee; Fan, Wendy; Ye, Qi; Han, Jie; Meyyappan, M.

    2003-01-01

    A reliable nanoelectrode array based on vertically aligned multi-walled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA detection. Characteristic nanoelectrode behavior is observed using low-density MWNT arrays for measuring both bulk and surface immobilized redox species such as K4Fe(CN)6 and ferrocene derivatives. The open-end of MWNTs are found to present similar properties as graphite edge-plane electrodes with wide potential window, flexible chemical functionalities, and good biocompatibility. BRCA1 related oligonucleotide probes with 18 bp are selectively functionalized at the open ends of the nanotube array and specifically hybridized with oligonucleotide targets incorporated with a polyG tag. The guanine groups are employed as the signal moieties in the electrochemical measurements. R(bpy)(sup 2+, sub 3) mediator is used to further amplify the guanine oxidation signal. The hybridization of sub-attomoles of DNA targets is detected electrochemically by combining the MWNT nanoelectrode array with the R(bpy)(sup 2+, sub 3) amplification mechanism. This technique was employed for direct electrochemical detection of label-free PCR amplicon from a healthy donor through specific hybridization with the BRCA1 probe. The detection limit is estimated to be less than 1000 DNA molecules since abundant guanine bases in the PCR amplicon provides a large signal. This system provides a general platform for rapid molecular diagnostics in applications requiring ultrahigh sensitivity, high-degree of miniaturization, and simple sample preparation, and low-cost operation.

  16. The Detection and Photometric Redshift Determination of Distant Galaxies using SIRTF's Infrared Array Camera

    NASA Technical Reports Server (NTRS)

    Simpson, C.; Eisenhardt, P.

    1998-01-01

    We investigate the ability of the Space Infrared Telescope Facility's Infrared Array Camera to detect distant (z3) galaxies and measure their photometric redshifts. Our analysis shows that changing the original long wavelength filter specifications provides significant improvements in performance in this and other areas.

  17. Detection of Regional Infrasound Signals Using Array Data - Testing, Tuning, and Physical Interpretation

    NASA Astrophysics Data System (ADS)

    Park, J.; Stump, B. W.; Hayward, C.; Arrowsmith, S.; Che, I. Y.; Drob, D. P.

    2015-12-01

    In order to understand the impact environmental conditions have on infrasound detection, an automated detector that accounts for both correlated and uncorrelated noise is run on data from a number of infrasonic arrays, all in a regional context. Data from six seismo-acoustic arrays in South Korea (BRDAR, CHNAR, KMPAR, KSGAR, TJIAR, and YPDAR), which are cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU), were used. An adaptive F-detector (AFD) (Arrowsmith et al., 2009) is applied that utilizes the F-statistic (Blandford, 1974) with an adaptive procedure that assesses variations in coherent noise in order to reduce false alarms. The adaptive procedure is characterized by the time dependent C-value that is found to depend on the weather conditions and local site effects. Arrays located on islands or near the coast produce noise power densities that are higher, consistent with both higher wind speeds as well as ocean wave contributions that vary seasonally. These results suggest that optimal detection processing requires careful characterization of background noise level and its relationship to enviornmental measures at individual arrays. This study also documents significant seasonal variations in infrasound detections including daily time of occurrence, total number of detections, and phase velocity/azimuth estimates. These time-dependent effects in most part explained by atmospheric models across the Korean peninsula as described by Drob et al. (2003).

  18. Shotgun isotope array for rapid, substrate-specific detection of microorganisms in a microbial community.

    PubMed

    Tobino, Tomohiro; Kurisu, Futoshi; Kasuga, Ikuro; Furumai, Hiroaki

    2011-10-01

    The shotgun isotope array method has been proposed to be an effective new tool for use in substrate-specific microbe exploration without any prior knowledge of the community composition. Proof of concept was demonstrated by detection of acetate-degrading microorganisms in activated sludge and further verified by independent stable isotope probing (SIP).

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

    NASA Technical Reports Server (NTRS)

    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.

  20. DNA detection on transistor arrays following mutation-specific enzymatic amplification

    NASA Astrophysics Data System (ADS)

    Pouthas, F.; Gentil, C.; Côte, D.; Bockelmann, U.

    2004-03-01

    An integrated array of silicon field-effect transistor structures is used for electronic detection of label-free DNA. Measurements of the dc current-voltage characteristics of the transistors gives us access to reproducible detection of single- and double-stranded DNA, locally adsorbed on the surface of the device. We combine this approach with allele-specific polymerase chain reaction, to test for the 35delG mutation, a frequent mutation related to prelingual nonsyndromic deafness.

  1. Imaging, object detection, and change detection with a polarized multistatic GPR array

    DOEpatents

    Beer, N. Reginald; Paglieroni, David W.

    2015-07-21

    A polarized detection system performs imaging, object detection, and change detection factoring in the orientation of an object relative to the orientation of transceivers. The polarized detection system may operate on one of several modes of operation based on whether the imaging, object detection, or change detection is performed separately for each transceiver orientation. In combined change mode, the polarized detection system performs imaging, object detection, and change detection separately for each transceiver orientation, and then combines changes across polarizations. In combined object mode, the polarized detection system performs imaging and object detection separately for each transceiver orientation, and then combines objects across polarizations and performs change detection on the result. In combined image mode, the polarized detection system performs imaging separately for each transceiver orientation, and then combines images across polarizations and performs object detection followed by change detection on the result.

  2. Real-time system for imaging and object detection with a multistatic GPR array

    DOEpatents

    Paglieroni, David W; Beer, N Reginald; Bond, Steven W; Top, Philip L; Chambers, David H; Mast, Jeffrey E; Donetti, John G; Mason, Blake C; Jones, Steven M

    2014-10-07

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

  3. Monolithic integration of GaAs SAW chemical microsensor arrays and detection electronics

    SciTech Connect

    CASALNUOVO,STEPHEN A.; HIETALA,VINCENT M.; HELLER,EDWIN J.; ASON,GREGORY CHARLES; BACA,ALBERT G.

    2000-04-17

    The authors describe the integration of an array of surface acoustic wave delay line chemical sensors with the associated RF microelectronics such that the resulting device operates in a DC in/DC out mode. The microelectronics design for on-chip RF generation and detection is presented. Both hybrid and monolithic approaches are discussed. This approach improves system performance, simplifies packaging and assembly, and significantly reduces overall system size. The array design can be readily scaled to include a large number of sensors.

  4. Detection and localization of particle-emitting sources with compound-eye inspired detector arrays

    NASA Astrophysics Data System (ADS)

    Liu, Zhi

    2007-08-01

    We develop methods to detect and localize particle-emitting sources using detector arrays that are inspired by biological compound eyes. The sources of interest may be optical, nuclear, or cosmic; they emit particles such as visible photons, neutrons, protons, or charged particles. Our results may have wide applications to artificial vision, which can be important in robotics (robot vision) or medicine (e.g., artificial eyes for the blind); security, where the detection of nuclear materials is needed; or astronomy. This dissertation consists of three parts. First, we detect a far-field particle source using two directional detector arrays: cubic and spherical. We propose a mean-difference test (MDT) detector, analyze its statistical performance, and show that the MDT has a number of advantages over the generalized likelihood- ratio test (GLRT). Second, we localize the source by proposing a novel biologically inspired detector array, whose configuration generalizes the compound eye of insects. This array combines the advantages of compound eyes (e.g., large field-of-view) and human eyes (e.g., high angular resolution). Based on a statistical model of the array measurements, we analyze the array performance by computing the Cramérao bound (CRB) on the error in estimating the source direction. We also derive lower bounds on the mean-square angular error (MSAE) of the source localization and investigate the MSAE of two source- direction estimators. Numerical examples, including the optimal array design, are presented to further illustrate the array performance. Third, we derive a statistical angular resolution limit (ARL) on resolving two closely spaced point sources in a three-dimensional frame, which is applicable to various measurement models (e.g., radar, sonar, or astronomy). Using the asymptotic analysis of the GLRT, we derive the ARL with constraints on the probabilities of false alarm and detection. Our results give explicit analytical expression for the ARL

  5. Comparison of two suspension arrays for simultaneous detection of five biothreat bacterial in powder samples.

    PubMed

    Yang, Yu; Wang, Jing; Wen, Haiyan; Liu, Hengchuan

    2012-01-01

    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. PMID:22690123

  6. Multiplexed protein detection using antibody-conjugated microbead arrays in a microfabricated electrophoretic device

    PubMed Central

    Barbee, Kristopher D.; Hsiao, Alexander P.; Roller, Eric E.; Huang, Xiaohua

    2011-01-01

    We report the development of a microfabricated electrophoretic device for assembling high-density arrays of antibody-conjugated microbeads for chip-based protein detection. The device consists of a flow cell formed between a gold-coated silicon chip with an array of microwells etched in a silicon dioxide film and a glass coverslip with a series of thin gold counter electrode lines. We have demonstrated that 0.4 and 1 μm beads conjugated with antibodies can be rapidly assembled into the microwells by applying a pulsed electric field across the chamber. By assembling step-wise a mixture of fluorescently labeled antibody-conjugated microbeads, we incorporated both spatial and fluorescence encoding strategies to demonstrate significant multiplexing capabilities. We have shown that these antibody-conjugated microbead arrays can be used to perform on-chip sandwich immunoassays to detect test antigens at concentrations as low as 40 pM (6 ng/mL). A finite element model was also developed to examine the electric field distribution within the device for different counter electrode configurations over a range of line pitches and chamber heights. This device will be useful for assembling high-density, encoded antibody arrays for multiplexed detection of proteins and other types of protein-conjugated microbeads for applications such as the analysis of protein-protein interactions. PMID:20820631

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

    PubMed Central

    Yang, Yu; Wang, Jing; Wen, Haiyan; Liu, Hengchuan

    2012-01-01

    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. PMID:22690123

  8. Water pollutant monitoring by a whole cell array through lens-free detection on CCD.

    PubMed

    Tsai, Hsieh-Fu; Tsai, Yi-Ching; Yagur-Kroll, Sharon; Palevsky, Noa; Belkin, Shimshon; Cheng, Ji-Yen

    2015-03-21

    Environmental contamination has become a serious problem to human and environmental health, as exposure to a wide range of possible contaminants continuously increases due to industrial and agricultural activities. Whole cell sensors have been proposed as a powerful tool to detect class-specific toxicants based upon their biological activity and bioavailability. We demonstrated a robust toxicant detection platform based on a bioluminescence whole cell sensor array biochip (LumiChip). LumiChip harbors an integrated temperature control and a 16-member sensor array, as well as a simple but highly efficient luminescence collection setup. On LumiChip, samples were infused in an oxygen-permeable microfluidic flow channel to reach the sensor array. Time-lapse changes in bioluminescence emitted by the array members were measured on a single window-removed linear charge-coupled device (CCD) commonly used in commercial industrial process control or in barcode readers. Removal of the protective window on the linear CCD allowed lens-free direct interfacing of LumiChip to the CCD surface for measurement with high light collection efficiency. Bioluminescence induced by simulated contamination events was detected within 15 to 45 minutes. The portable LumiSense system utilizing the linear CCD in combination with the miniaturized LumiChip is a promising potential platform for on-site environmental monitoring of toxicant contamination.

  9. 64-element photodiode array for scintillation detection of x-rays

    NASA Astrophysics Data System (ADS)

    Wegrzecki, Maciej; Wolski, Dariusz; Bar, Jan; Budzyński, Tadeusz; Chłopik, Arkadiusz; Grabiec, Piotr; Kłos, Helena; Panas, Andrzej; Piotrowski, Tadeusz; Słysz, Wojciech; Stolarski, Maciej; Szmigiel, Dariusz; Wegrzecka, Iwona; Zaborowski, Michał

    2014-08-01

    The paper presents the design, technology and parameters of a new, silicon 64-element linear photodiode array developed at the Institute of Electron Technology (ITE) for the detection of scintillations emitted by CsI scintillators (λ≈550 nm). The arrays are used in a device for examining the content of containers at border crossings under development at the National Centre for Nuclear Research. Two arrays connected with a scintillator block (128 CsI scintillators) form a 128-channel detection module. The array consists of 64 epiplanar photodiode structures (5.1 × 7.2 mm) and a 5.3 mm module. p+-ν-n+ photodiode structures are optimised for the detection of radiation of λ≈ 550 nm wavelength with no voltage applied (photovoltaic mode). The structures are mounted on an epoxy-glass laminate substrate, copper-clad on both sides, on which connections with a common anode and separate cathode leads are located. The photosensitive surface of photodiodes is covered with a special silicone gel, which protects photodiodes against the mechanical impact of scintillators

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

    PubMed Central

    Du, Yi-Chun; Lim, Bee-Yen; Ciou, Wei-Siang; Wu, Ming-Jui

    2016-01-01

    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. PMID:27294927

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

    PubMed

    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. PMID:21807207

  12. Periodic Application of Concurrent Error Detection in Processor Array Architectures. PhD. Thesis -

    NASA Technical Reports Server (NTRS)

    Chen, Paul Peichuan

    1993-01-01

    Processor arrays can provide an attractive architecture for some applications. Featuring modularity, regular interconnection and high parallelism, such arrays are well-suited for VLSI/WSI implementations, and applications with high computational requirements, such as real-time signal processing. Preserving the integrity of results can be of paramount importance for certain applications. In these cases, fault tolerance should be used to ensure reliable delivery of a system's service. One aspect of fault tolerance is the detection of errors caused by faults. Concurrent error detection (CED) techniques offer the advantage that transient and intermittent faults may be detected with greater probability than with off-line diagnostic tests. Applying time-redundant CED techniques can reduce hardware redundancy costs. However, most time-redundant CED techniques degrade a system's performance.

  13. Patterned polymer nanowire arrays as an effective protein immobilizer for biosensing and HIV detection

    NASA Astrophysics Data System (ADS)

    Shen, Yue; Liu, Yingyi; Zhu, Guang; Fang, Hao; Huang, Yunhui; Jiang, Xingyu; Wang, Zhong L.

    2012-12-01

    We report an array of polymeric nanowires for effectively immobilizing biomolecules on biochips owing to the large surface area. The nanowires were fabricated in predesigned patterns using an inductively coupled plasma (ICP) etching process. Microfluidic biochips integrated using the substrates with arrays of nanowires and polydimethylsiloxane channels have been demonstrated to be effective for detecting antigens, and a detection limit of antigens at 0.2 μg mL-1 has been achieved, which is improved by a factor of 50 compared to that based on flat substrates without the nanowires. In addition, the high sensitivity for clinical detection of human immunodeficiency virus (HIV) antibody has also been demonstrated, showing a 20 times enhancement in fluorescent signal intensity between the samples with positive and negative HIV.

  14. Surface-Enhanced Raman Spectroscopy on Liquid Interfacial Nanoparticle Arrays for Multiplex Detecting Drugs in Urine.

    PubMed

    Ma, Yongmei; Liu, Honglin; Mao, Mei; Meng, Juan; Yang, Liangbao; Liu, Jinhuai

    2016-08-16

    The design and application of liquid interfacial plasmonic platform is still in its infancy but is an exciting topic in tunable optical devices, sensors, and catalysis. Here, we developed an interfacial surface-enhanced Raman scattering (SERS) platform through the large-scale self-assembly of gold nanoparticle (GNP) arrays at the cyclohexane (CYH)/water interface for detecting trace drug molecules in the urine of humans. The molecules extracted by the CYH phase from a urine sample were directly localized into the self-organized plasmonic hotspots, yielded excellent Raman enhancement, and realized the substrate-free interfacial SERS detection. Synchrotron radiation small-angle X-ray scattering (SR-SAXS) experiments reveals a good uniformity of approximately 2-3 nm interparticle distance in the GNP arrays. SERS colocalization experiments demonstrated that amphetamine molecules of different concentration levels could be loaded into the interfacial GNP arrays and realized the coassembly together with nanoparticles at the liquid/liquid interface. Interfacial GNP arrays with dynamic nanogaps in liquid interfacial structure can make surrounding molecules easily diffuse into the nanogaps. In contrast, the fixed GNP arrays on Si wafer were more irregular, such as multilayer stack, random aggregates, and voids, during the drying process. When the drugs directly participate in the self-assembly process, it becomes easier for analytes diffusing into the nanogaps of GNP arrays, produces a concentration effect, and amplified the SERS sensitivity. This feature also enables molecules to be adsorbed evenly in the arrays and makes a more uniform distribution of both the analytes and GNPs in the liquid interface and realizes the significant increase in signal reproducibility. Interfacial SERS produced a standard deviation of 12.5% at 1001 cm(-1) peak of methamphetamine (MAMP) molecules under the concentration of 1 ppm, implying a good reproducibility. Moreover, dual-analyte detection

  15. Motorcycle detection and counting using stereo camera, IR camera, and microphone array

    NASA Astrophysics Data System (ADS)

    Ling, Bo; Gibson, David R. P.; Middleton, Dan

    2013-03-01

    Detection, classification, and characterization are the key to enhancing motorcycle safety, motorcycle operations and motorcycle travel estimation. Average motorcycle fatalities per Vehicle Mile Traveled (VMT) are currently estimated at 30 times those of auto fatalities. Although it has been an active research area for many years, motorcycle detection still remains a challenging task. Working with FHWA, we have developed a hybrid motorcycle detection and counting system using a suite of sensors including stereo camera, thermal IR camera and unidirectional microphone array. The IR thermal camera can capture the unique thermal signatures associated with the motorcycle's exhaust pipes that often show bright elongated blobs in IR images. The stereo camera in the system is used to detect the motorcyclist who can be easily windowed out in the stereo disparity map. If the motorcyclist is detected through his or her 3D body recognition, motorcycle is detected. Microphones are used to detect motorcycles that often produce low frequency acoustic signals. All three microphones in the microphone array are placed in strategic locations on the sensor platform to minimize the interferences of background noises from sources such as rain and wind. Field test results show that this hybrid motorcycle detection and counting system has an excellent performance.

  16. The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor

    NASA Astrophysics Data System (ADS)

    Banerjee, Subarna; Mohapatra, Susanta K.; Misra, Mano; Mishra, Indu B.

    2009-02-01

    There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Seismicity of Dronning Maud Land/antarctica As Detected By The Neumayer Seismological Array

    NASA Astrophysics Data System (ADS)

    Eckstaller, A.; Mueller, C.; Hoffmann, M.

    Array seismology provides a powerful tool for improving detection and localization capabilities for monitoring weak seismic events. Little is known about seismic activity of the Antarctic continent due to the sparse station deployment of the global network in this region. To improve monitoring capabilities a small-aperture short-period detec- tion array was installed in the vicinity of the German base Neumayer/Dronning Maud Land. The array complements the Neumayer seismograph network and the broadband seismograph SNAA at the neighbouring South African base Sanae IV. The array was installed in the austral summer season 1997 and has been operational almost continu- ously since that time. The design was adopted from the SPITS-array in Svalbard and consists of 15 short-period vertical seismometers arranged on three concentric rings around the 3-component intermediate-period seismometer in the center. Event detec- tion and beamforming is done automatically using array processing software from NORSAR. With this seismic antenna the number of detected Antarctic earthquakes was increased significantly. In particular, two seismically active regions were identified along the Jutul-Penck-Graben and off Kapp Norvegia. The nature of this seismic activity is not yet fully understood. Especially, the Jutul-Penck-Graben region is of interest since the question arises if this is an active tectonic rift system or if the seismic activity origi- nates from post-glacial rebound movements. Better knowledge of hypocentral depths and focal mechanisms will contribute to the understanding of these mechanisms. An integrated approach by using temporary local networks including geodetical and air- borne geophysical measurements may reveal the mechanisms of these neotectonic dynamics.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Multi-colorimetric sensor array for detection of explosives in gas and liquid phase

    NASA Astrophysics Data System (ADS)

    Kostesha, N.; Alstrøm, T. S.; Johnsen, C.; Nielsen, K. A.; Jeppesen, J. O.; Larsen, J.; Boisen, A.; Jakobsen, M. H.

    2011-05-01

    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, TATP, HMX, RDX and identification of reagents needed for making homemade explosives. 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 to the analytes creates a color difference map which gives a unique fingerprint for each explosive and VOCs. Such sensing technology can be used for screening relevant explosives in a complex background as well as to distinguish mixtures of volatile organic compounds distributed in gas and liquid phases. This sensor array is inexpensive, and can potentially be produced as single use disposable.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. ZnO nano-array-based EGFET biosensor for glucose detection

    NASA Astrophysics Data System (ADS)

    Qi, Junjie; Zhang, Huihui; Ji, Zhaoxia; Xu, Minxuan; Zhang, Yue

    2015-06-01

    Electrochemical biosensors are normally based on enzymatic catalysis of a reaction that produces or consumes electrons and the sensing membranes dominate the performance. In this work, ZnO nano-array-based EGFETs were fabricated for pH and glucose detection. The ZnO nano-arrays prepared via low-temperature hydrothermal method were well-aligned, with an average length of 2 μm and diameter of 100-150 nm, and have a typical hexagonal wurtzite structure. The sensor performed with a sensitivity of 45 mV/pH and response time of about 6-7 s from pH = 4-12. UV irradiation can improve the Vref response as a result of the formation of a depletion region at the surface of ZnO nanomaterials. Due to its high specific surface area, the ZnO nano-array EGFET sensor showed a sensitivity of -0.395 mV/μM to the glucose detection in a concentration range between 20 and 100 μM. These EGFET glucose biosensors demonstrate a low detectable concentration (20 μM) with good linearity, therefore may be used to detect glucose in saliva and tears at much lower concentrations than that in blood.

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

    PubMed

    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.

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

    PubMed

    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. PMID:25913282

  6. Accuracy requirements of optical linear algebra processors in adaptive optics imaging systems

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Goodman, Joseph W.

    1989-01-01

    The accuracy requirements of optical processors in adaptive optics systems are determined by estimating the required accuracy in a general optical linear algebra processor (OLAP) that results in a smaller average residual aberration than that achieved with a conventional electronic digital processor with some specific computation speed. Special attention is given to an error analysis of a general OLAP with regard to the residual aberration that is created in an adaptive mirror system by the inaccuracies of the processor, and to the effect of computational speed of an electronic processor on the correction. Results are presented on the ability of an OLAP to compete with a digital processor in various situations.

  7. Microsphere suspension array assays for detection and differentiation of Hendra and Nipah viruses.

    PubMed

    Foord, Adam J; White, John R; Colling, Axel; Heine, Hans G

    2013-01-01

    Microsphere suspension array systems enable the simultaneous fluorescent identification of multiple separate nucleotide targets in a single reaction. We have utilized commercially available oligo-tagged microspheres (Luminex MagPlex-TAG) to construct and evaluate multiplexed assays for the detection and differentiation of Hendra virus (HeV) and Nipah virus (NiV). Both these agents are bat-borne zoonotic paramyxoviruses of increasing concern for veterinary and human health. Assays were developed targeting multiple sites within the nucleoprotein (N) and phosphoprotein (P) encoding genes. The relative specificities and sensitivities of the assays were determined using reference isolates of each virus type, samples from experimentally infected horses, and archival veterinary diagnostic submissions. Results were assessed in direct comparison with an established qPCR. The microsphere array assays achieved unequivocal differentiation of HeV and NiV and the sensitivity of HeV detection was comparable to qPCR, indicating high analytical and diagnostic specificity and sensitivity.

  8. Report on demonstration project: imaging detection of unexploded ordinance using giant magnetoresistive sensor arrays

    SciTech Connect

    Chaiken, A., LLNL

    1996-09-01

    The goal of the project was to demonstrate the feasibility of the detection of buried unexploded ordnance (UXO) using giant magnetoresistive (GMR) sensor arrays. 3x3 and 5x5 arrays of off-the-shelf GMR sensors were purchased from Nonvolatile Electronics (NVE) and were interfaced with a data acquisition card and a personal computer. Magnetic images were obtained from a number of ferrous objects, such as threadstock, bolts, and rebar. These images can be interpreted in terms of the remanent magnetic state of the objects. The ability of the GMR sensor approach to discriminate among magnetic objects is assessed and the design of a more realistic UXO detection system is discussed.

  9. DETECTION OF MULTIPLE BIPOLAR FLOWS IN NGC 7027 WITH SUBMILLIMETER ARRAY

    SciTech Connect

    Huang Zhenyuan; Hasegawa, Tatsuhiko I.; Dinh-V-Trung; Kwok, Sun; Muller, Sebastien; Hirano, Naomi; Lim, Jeremy; Muthu Mariappan, C.; Lyo, Aran E-mail: hirano@asiaa.sinica.edu.t E-mail: trung@asiaa.sinica.edu.t E-mail: jlim@asiaa.sinica.edu.t E-mail: muthu@aries.ernet.i

    2010-10-10

    Highly collimated multiple bipolar flows are detected with a 3'' resolution in the HCO{sup +} (J = 3-2) and HCN (J = 3-2) lines in the young planetary nebula NGC 7027 with the Submillimeter Array. The HCO{sup +} and HCN flows coincide in location and velocity with compact and fast CO flows detected with {approx}6'' resolutions with other millimeter arrays. The equatorial molecular torus of NGC 7027 is captured in HCO{sup +} emission in the present observations. The HCO{sup +} emission also closely follows the H{sub 2} emission, indicating that the present observations probe the photon-dominated region of the molecular envelope of NGC 7027.

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

    NASA Astrophysics Data System (ADS)

    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. Highly Sensitive Multi-Channel IDC Sensor Array for Low Concentration Taste Detection

    PubMed Central

    Khan, Md. Rajibur Rahaman; Kang, Shin-Won

    2015-01-01

    In this study, we designed and developed an interdigitated capacitor (IDC)-based taste sensor array to detect different taste substances. The designed taste sensing array has four IDC sensing elements. The four IDC taste sensing elements of the array are fabricated by incorporating four different types of lipids into the polymer, dioctyl phenylphosphonate (DOPP) and tetrahydrofuran (THF) to make the respective dielectric materials that are individually placed onto an interdigitated electrode (IDE) via spin coating. When the dielectric material of an IDC sensing element comes into contact with a taste substance, its dielectric properties change with the capacitance of the IDC sensing element; this, in turn, changes the voltage across the IDC, as well as the output voltage of each channel of the system. In order to assess the effectiveness of the sensing system, four taste substances, namely sourness (HCl), saltiness (NaCl), sweetness (glucose) and bitterness (quinine-HCl), were tested. The IDC taste sensor array had rapid response and recovery times of about 12.9 s and 13.39 s, respectively, with highly stable response properties. The response property of the proposed IDC taste sensor array was linear, and its correlation coefficient R2 was about 0.9958 over the dynamic range of the taste sensor array as the taste substance concentration was varied from 1 μM to 1 M. The proposed IDC taste sensor array has several other advantages, such as real-time monitoring capabilities, high sensitivity 45.78 mV/decade, good reproducibility with a standard deviation of about 0.029 and compactness, and the circuitry is based on readily available and inexpensive electronic components. The proposed IDC taste sensor array was compared with the potentiometric taste sensor with respect to sensitivity, dynamic range width, linearity and response time. We found that the proposed IDC sensor array has better performance. Finally, principal component analysis (PCA) was applied to

  12. Impact of blocking and detection chemistries on antibody performance for reverse phase protein arrays.

    PubMed

    Ambroz, Kristi

    2011-01-01

    Careful selection of well-qualified antibodies is critical for accurate data collection from reverse phase protein arrays (RPPA). The most common way to qualify antibodies for RPPA analysis is by Western blotting because the detection mechanism is based on the same immunodetection principles. Western blots of tissue or cell lysates that result in single bands and low cross-reactivity indicate appropriate antibodies for RPPA detection. Western blot conditions used to validate antibodies for RPPA experiments, including blocking and detection reagents, have significant effects on aspects of antibody performance such as cross-reactivity against other proteins in the sample. We have found that there can be a dramatic impact on antibody behavior with changes in blocking reagent and detection method, and offer an alternative method that allows detection reagents and conditions to be held constant in both antibody validation and RPPA experiments. PMID:21901590

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Detection of regional infrasound signals using array data: Testing, tuning, and physical interpretation.

    PubMed

    Park, Junghyun; Stump, Brian W; Hayward, Chris; Arrowsmith, Stephen J; Che, Il-Young; Drob, Douglas P

    2016-07-01

    This work quantifies the physical characteristics of infrasound signal and noise, assesses their temporal variations, and determines the degree to which these effects can be predicted by time-varying atmospheric models to estimate array and network performance. An automated detector that accounts for both correlated and uncorrelated noise is applied to infrasound data from three seismo-acoustic arrays in South Korea (BRDAR, CHNAR, and KSGAR), cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU). Arrays located on an island and near the coast have higher noise power, consistent with both higher wind speeds and seasonably variable ocean wave contributions. On the basis of the adaptive F-detector quantification of time variable environmental effects, the time-dependent scaling variable is shown to be dependent on both weather conditions and local site effects. Significant seasonal variations in infrasound detections including daily time of occurrence, detection numbers, and phase velocity/azimuth estimates are documented. These time-dependent effects are strongly correlated with atmospheric winds and temperatures and are predicted by available atmospheric specifications. This suggests that commonly available atmospheric specifications can be used to predict both station and network detection performance, and an appropriate forward model improves location capabilities as a function of time. PMID:27475150

  18. Detection of regional infrasound signals using array data: Testing, tuning, and physical interpretation

    DOE PAGES

    Park, Junghyun; Stump, Brian W.; Hayward, Chris; Arrowsmith, Stephen J.; Che, Il-Young; Drob, Douglas P.

    2016-07-14

    This work quantifies the physical characteristics of infrasound signal and noise, assesses their temporal variations, and determines the degree to which these effects can be predicted by time-varying atmospheric models to estimate array and network performance. An automated detector that accounts for both correlated and uncorrelated noise is applied to infrasound data from three seismo-acoustic arrays in South Korea (BRDAR, CHNAR, and KSGAR), cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU). Arrays located on an island and near the coast have higher noise power, consistent with both higher wind speeds and seasonablymore » variable ocean wave contributions. On the basis of the adaptive F-detector quantification of time variable environmental effects, the time-dependent scaling variable is shown to be dependent on both weather conditions and local site effects. Significant seasonal variations in infrasound detections including daily time of occurrence, detection numbers, and phase velocity/azimuth estimates are documented. These time-dependent effects are strongly correlated with atmospheric winds and temperatures and are predicted by available atmospheric specifications. As a result, this suggests that commonly available atmospheric specifications can be used to predict both station and network detection performance, and an appropriate forward model improves location capabilities as a function of time.« less

  19. Instantaneous dynamic change detection based on three-line-array stereoscopic images of TH-1 satellite

    NASA Astrophysics Data System (ADS)

    Zheng, Tuanjie; Cheng, Jiasheng; Li, Heyuan

    2014-05-01

    TH-1 satellite loading three-line array stereoscopic camera, can scanning 3 times from different directions on the same region or target within the time for about 1 minute, conducive to regional monitoring or target instantaneous change monitoring. Based on the time difference of forward, nadir and backward images of the three-line-array camera of TH-1 Satellite, this paper gives a method to get regional dynamic change image by processing of geometric and physical consistency under the principle of photogrammetry, and to construct the model of change detection by the quantitative results of change detection under the improvement and optimization of noise filtering algorithm. The experimental results show that, by using the detection results of forward, nadir and backward images of the three-line -array camera of TH-1 Satellite, moving distance and velocity can be accurately calculated, and quantitative monitoring of topography changes can be achieved, which not only has temporal resolution, but also can't be achieved by other environmental monitoring satellites. It's significant for flood, fire, clouds, or motion detectors. TH-1 satellite is China's first generation of transmission photogrammetry satellite. With the more satellites networking operation, and higher spatial and temporal resolution, The TH satellites will play a greater role in the field of Earth observation. This article merely uses the principles of photogrammetry to consider photography deformation from different directions, and thorough study will aim at shadow and sun elevation angle, to fully realize the monitoring of changes in topography and moving targets.

  20. Rapid and multiplex microRNA detection on graphically encoded silica suspension array.

    PubMed

    Jiang, Li; Shen, Ye; Zheng, Kexiao; Li, Jiong

    2014-11-15

    MicroRNA (miRNA), an 18-24-nucleotide noncoding RNA molecule, has become an ideal class of biomarker candidates for clinical diagnosis of cancers. By now, a number of detection methods for miRNAs have been developed on planar arrays and suspension arrays. In this work, we describe a hybridization-triggered fluorescence strategy for label-free and multiplex miRNA detection on graphically encoded silica suspension array. The total RNA is directly applied for analysis with an 8-mer Universal Tag which can be selectively captured by the capture probe via base-stacking effects. Benefiting from base-stacking effects, this novel method exhibits superb discrimination ability toward the 5' and 3' end single-nucleotide alteration. Mature miRNAs can be distinguished from their corresponding pre-miRNAs easily. Moreover, the estimated detection limit of 5 amol is comparable to some of the most sensitive methods. All these mentioned characteristics offer exciting possibilities for discovery and clinical applications.

  1. Detection of regional infrasound signals using array data: Testing, tuning, and physical interpretation.

    PubMed

    Park, Junghyun; Stump, Brian W; Hayward, Chris; Arrowsmith, Stephen J; Che, Il-Young; Drob, Douglas P

    2016-07-01

    This work quantifies the physical characteristics of infrasound signal and noise, assesses their temporal variations, and determines the degree to which these effects can be predicted by time-varying atmospheric models to estimate array and network performance. An automated detector that accounts for both correlated and uncorrelated noise is applied to infrasound data from three seismo-acoustic arrays in South Korea (BRDAR, CHNAR, and KSGAR), cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU). Arrays located on an island and near the coast have higher noise power, consistent with both higher wind speeds and seasonably variable ocean wave contributions. On the basis of the adaptive F-detector quantification of time variable environmental effects, the time-dependent scaling variable is shown to be dependent on both weather conditions and local site effects. Significant seasonal variations in infrasound detections including daily time of occurrence, detection numbers, and phase velocity/azimuth estimates are documented. These time-dependent effects are strongly correlated with atmospheric winds and temperatures and are predicted by available atmospheric specifications. This suggests that commonly available atmospheric specifications can be used to predict both station and network detection performance, and an appropriate forward model improves location capabilities as a function of time.

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

    NASA Astrophysics Data System (ADS)

    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 (< 2500 Hz), coherent hydrophone array system are detected and analyzed for signal energy level and other characteristics. The vocalizing individuals are localized in bearing, range, and depth. An algorithm is 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.

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

    PubMed Central

    Wang, Xuan; Mu, Zhongde; Shangguan, Fengqi; Liu, Ran; Pu, Yuepu; Yin, Lihong

    2013-01-01

    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. PMID:23805266

  4. Micromechanical cantilever array sensors for selective fungal immobilization and fast growth detection.

    PubMed

    Nugaeva, Natalia; Gfeller, Karin Y; Backmann, Natalija; Lang, Hans Peter; Düggelin, Marcel; Hegner, Martin

    2005-12-15

    We demonstrate the use of micromechanical cantilever arrays for selective immobilization and fast quantitative detection of vital fungal spores. Micro-fabricated uncoated as well as gold-coated silicon cantilevers were functionalized with concanavalin A, fibronectin or immunoglobulin G. In our experiments two major morphological fungal forms were used--the mycelial form Aspergillus niger and the unicellular yeast form Saccharomyces cerevisiae, as models to explore a new method for growth detection of eukaryotic organisms using cantilever arrays. We exploited the specific biomolecular interactions of surface grafted proteins with the molecular structures on the fungal cell surface. It was found that these proteins have different affinities and efficiencies to bind the spores. Maximum spore immobilization, germination and mycelium growth was observed on the immunoglobulin G functionalized cantilever surfaces. We show that spore immobilization and germination of the mycelial fungus A. niger and yeast S. cerevisiae led to shifts in resonance frequency within a few hours as measured by dynamically operated cantilever arrays, whereas conventional techniques would require several days. The biosensor could detect the target fungi in a range of 10(3) - 10(6) CFUml(-1). The measured shift is proportional to the mass of single fungal spores and can be used to evaluate spore contamination levels. Applications lie in the field of medical and agricultural diagnostics, food- and water-quality monitoring.

  5. Metal enhanced fluorescence improved protein and DNA detection by zigzag Ag nanorod arrays.

    PubMed

    Ji, Xiaofan; Xiao, Chenyu; Lau, Wai-Fung; Li, Jianping; Fu, Junxue

    2016-08-15

    As metal nano-arrays show great potential on metal enhanced fluorescence (MEF) than random nanostructures, MEF of Ag zigzag nanorod (ZNR) arrays made by oblique angle deposition has been studied for biomolecule-protein interaction and DNA hybridization. By changing the folding number and the deposition substrate temperature, a 14-fold enhancement factor (EF) is obtained for biotin-neutravidin detection. The optimal folding number is decided as Z=7, owing to the high scattering intensity of Ag ZNRs. The substrate temperature T=25°C and 0°C slightly alters the morphology of Ag ZNRs but has no big difference in EF. Further, Ag ZNRs deposited on a layer of Ag film have been introduced to the DNA hybridization and a significant signal enhancement has been observed through the fluorescence microscope. Through a detailed quantitative EF analysis, which excludes the enhancing effect from the increased surface area of ZNRs and only considers the contribution of MEF, an EF of 28 is achieved for the hybridization of two single-stranded oligonucleotides with 33 bases. Furthermore, a limit of detection is determined as 0.01pM. We believe that the Ag ZNR arrays can serve as a universal and sensitive bio-detection platform. PMID:27088369

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

    SciTech Connect

    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.

  7. Characterization of protein expression levels with label-free detected reverse phase protein arrays.

    PubMed

    Guo, Xuexue; Deng, Yihong; Zhu, Chenggang; Cai, Junlong; Zhu, Xiangdong; Landry, James P; Zheng, Fengyun; Cheng, Xunjia; Fei, Yiyan

    2016-09-15

    In reverse-phase protein arrays (RPPA), one immobilizes complex samples (e.g., cellular lysate, tissue lysate or serum etc.) on solid supports and performs parallel reactions of antibodies with immobilized protein targets from the complex samples. In this work, we describe a label-free detection of RPPA that enables quantification of RPPA data and thus facilitates comparison of studies performed on different samples and on different solid supports. We applied this detection platform to characterization of phosphoserine aminotransferase (PSAT) expression levels in Acanthamoeba lysates treated with artemether and the results were confirmed by Western blot studies. PMID:27372609

  8. Detection of foreign body using fast thermoacoustic tomography with a multielement linear transducer array

    SciTech Connect

    Nie Liming; Xing Da; Yang Diwu; Zeng Lvming; Zhou Quan

    2007-04-23

    Current imaging modalities face challenges in clinical applications due to limitations in resolution or contrast. Microwave-induced thermoacoustic imaging may provide a complementary modality for medical imaging, particularly for detecting foreign objects due to their different absorption of electromagnetic radiation at specific frequencies. A thermoacoustic tomography system with a multielement linear transducer array was developed and used to detect foreign objects in tissue. Radiography and thermoacoustic images of objects with different electromagnetic properties, including glass, sand, and iron, were compared. The authors' results demonstrate that thermoacoustic imaging has the potential to become a fast method for surgical localization of occult foreign objects.

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

    SciTech Connect

    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.

  10. A high-accuracy optical linear algebra processor for finite element applications

    NASA Technical Reports Server (NTRS)

    Casasent, D.; Taylor, B. K.

    1984-01-01

    Optical linear processors are computationally efficient computers for solving matrix-matrix and matrix-vector oriented problems. Optical system errors limit their dynamic range to 30-40 dB, which limits their accuray to 9-12 bits. Large problems, such as the finite element problem in structural mechanics (with tens or hundreds of thousands of variables) which can exploit the speed of optical processors, require the 32 bit accuracy obtainable from digital machines. To obtain this required 32 bit accuracy with an optical processor, the data can be digitally encoded, thereby reducing the dynamic range requirements of the optical system (i.e., decreasing the effect of optical errors on the data) while providing increased accuracy. This report describes a new digitally encoded optical linear algebra processor architecture for solving finite element and banded matrix-vector problems. A linear static plate bending case study is described which quantities the processor requirements. Multiplication by digital convolution is explained, and the digitally encoded optical processor architecture is advanced.

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

    PubMed Central

    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

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

    PubMed

    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; Domínguez, J

    2016-04-01

    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 inrpoB,katG, andinhAassociated with resistance to rifampin and isoniazid. PMID:26865688

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    Labroo, Pratima; Cui, Yue

    2014-02-27

    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. PMID:24528665

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

    PubMed Central

    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. PMID:22016625

  16. Ultrasensitive Detection of Dual Cancer Biomarkers with Integrated CMOS-Compatible Nanowire Arrays.

    PubMed

    Lu, Na; Gao, Anran; Dai, Pengfei; Mao, Hongju; Zuo, Xiaolei; Fan, Chunhai; Wang, Yuelin; Li, Tie

    2015-11-17

    A direct, rapid, highly sensitive and specific biosensor for detection of cancer biomarkers is desirable in early diagnosis and prognosis of cancer. However, the existing methods of detecting cancer biomarkers suffer from poor sensitivity as well as the requirement of enzymatic labeling or nanoparticle conjugations. Here, we proposed a two-channel PDMS microfluidic integrated CMOS-compatible silicon nanowire (SiNW) field-effect transistor arrays with potentially single use for label-free and ultrasensitive electrical detection of cancer biomarkers. The integrated nanowire arrays showed not only ultrahigh sensitivity of cytokeratin 19 fragment (CYFRA21-1) and prostate specific antigen (PSA) with detection to at least 1 fg/mL in buffer solution but also highly selectivity of discrimination from other similar cancer biomarkers. In addition, this method was used to detect both CYFRA21-1 and PSA real samples as low as 10 fg/mL in undiluted human serums. With its excellent properties and miniaturization, the integrated SiNW-FET device opens up great opportunities for a point-of-care test (POCT) for quick screening and early diagnosis of cancer and other complex diseases. PMID:26473941

  17. Ultra-sensitive detection of adipocytokines with CMOS-compatible silicon nanowire arrays

    NASA Astrophysics Data System (ADS)

    Pui, Tze-Sian; Agarwal, Ajay; Ye, Feng; Tou, Zhi-Qiang; Huang, Yinxi; Chen, Peng

    2009-09-01

    Perfectly aligned arrays of single-crystalline silicon nanowires were fabricated using top-down CMOS-compatible techniques. We demonstrate that these nanowire devices are able to detect adipocytokines secreted by adipose cells with femtomolar sensitivity, high specificity, wide detection range, and ability for parallel monitoring. The nanowire sensors also provide a novel tool to reveal the poorly understood signaling mechanisms of these newly recognized signaling molecules, as well as their relevance in common diseases such as obesity and diabetes.Perfectly aligned arrays of single-crystalline silicon nanowires were fabricated using top-down CMOS-compatible techniques. We demonstrate that these nanowire devices are able to detect adipocytokines secreted by adipose cells with femtomolar sensitivity, high specificity, wide detection range, and ability for parallel monitoring. The nanowire sensors also provide a novel tool to reveal the poorly understood signaling mechanisms of these newly recognized signaling molecules, as well as their relevance in common diseases such as obesity and diabetes. Electronic supplementary information (ESI) available: Process diagram of nanowire fabrication; specificity of nanowire detection; induced differentiation of 3T3-L1 cells. See DOI: 10.1039/b9nr00092e

  18. Mode-shape-based mass detection scheme using mechanically diverse, indirectly coupled microresonator arrays

    NASA Astrophysics Data System (ADS)

    Glean, Aldo A.; Judge, John A.; Vignola, Joseph F.; Ryan, Teresa J.

    2015-02-01

    We explore vibration localization in arrays of microresonators used for ultrasensitive mass detection and describe an algorithm for identifying the location and amount of added mass using measurements of a vibration mode of the system. For a set of sensing elements coupled through a common shuttle mass, the inter-element coupling is shown to be proportional to the ratio of the element masses to the shuttle mass and to vary with the frequency mistuning between any two sensing elements. When any two elements have sufficiently similar frequencies, mass adsorption on one element can result in measurable changes to multiple modes of the system. We describe the effects on system frequencies and mode shapes due to added mass, in terms of mass ratio and frequency spacing. In cases in which modes are not fully localized, frequency-shift-based mass detection methods may give ambiguous results. The mode-shape-based detection algorithm presented uses a single measured mode shape and corresponding natural frequency to identify the location and amount of added mass. Mass detection in the presence of measurement noise is numerically simulated using a ten element sensor array. The accuracy of the detection scheme is shown to depend on the amplitude with which each element vibrates in the chosen mode.

  19. DETECTION OF FAST RADIO TRANSIENTS WITH MULTIPLE STATIONS: A CASE STUDY USING THE VERY LONG BASELINE ARRAY

    SciTech Connect

    Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.; Brisken, Walter F.; Deller, Adam T.; Tingay, Steven J.; Wayth, Randall B.

    2011-07-10

    Recent investigations reveal an important new class of transient radio phenomena that occur on submillisecond timescales. Often, transient surveys' data volumes are too large to archive exhaustively. Instead, an online 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. 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 Array.

  20. Detection of Fast Radio Transients with Multiple Stations: A Case Study Using the Very Long Baseline Array

    NASA Astrophysics Data System (ADS)

    Thompson, David R.; Wagstaff, Kiri L.; Brisken, Walter F.; Deller, Adam T.; Majid, Walid A.; Tingay, Steven J.; Wayth, Randall B.

    2011-07-01

    Recent investigations reveal an important new class of transient radio phenomena that occur on submillisecond timescales. Often, transient surveys' data volumes are too large to archive exhaustively. Instead, an online 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. 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 Array.

  1. Fast Confocal Raman Imaging Using a 2-D Multifocal Array for Parallel Hyperspectral Detection.

    PubMed

    Kong, Lingbo; Navas-Moreno, Maria; Chan, James W

    2016-01-19

    We present the development of a novel confocal hyperspectral Raman microscope capable of imaging at speeds up to 100 times faster than conventional point-scan Raman microscopy under high noise conditions. The microscope utilizes scanning galvomirrors to generate a two-dimensional (2-D) multifocal array at the sample plane, generating Raman signals simultaneously at each focus of the array pattern. The signals are combined into a single beam and delivered through a confocal pinhole before being focused through the slit of a spectrometer. To separate the signals from each row of the array, a synchronized scan mirror placed in front of the spectrometer slit positions the Raman signals onto different pixel rows of the detector. We devised an approach to deconvolve the superimposed signals and retrieve the individual spectra at each focal position within a given row. The galvomirrors were programmed to scan different focal arrays following Hadamard encoding patterns. A key feature of the Hadamard detection is the reconstruction of individual spectra with improved signal-to-noise ratio. Using polystyrene beads as test samples, we demonstrated not only that our system images faster than a conventional point-scan method but that it is especially advantageous under noisy conditions, such as when the CCD detector operates at fast read-out rates and high temperatures. This is the first demonstration of multifocal confocal Raman imaging in which parallel spectral detection is implemented along both axes of the CCD detector chip. We envision this novel 2-D multifocal spectral detection technique can be used to develop faster imaging spontaneous Raman microscopes with lower cost detectors. PMID:26654100

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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.

  4. Bead-based suspension array for simultaneous differential detection of five major swine viruses.

    PubMed

    Chen, Ru; Yu, Xiao-Lu; Gao, Xiao-Bo; Xue, Cun-Yi; Song, Chang-Xu; Li, Yan; Cao, Yong-Chang

    2015-01-01

    A novel multiplex detection array based on Luminex xMAP technology was developed and validated for simultaneous detection of five major viruses causing swine reproductive diseases. By combining one-step asymmetric multiplex reverse transcription polymerase chain reaction (RT-PCR) with xMAP bead-based hybridization and flow cytometry analysis, the resulting multiplex assay was capable of detecting single and mixed infections of PRRSV, PCV-2, PRV, CSFV, and PPV in a single reaction. The assay accurately detected and differentiated 23 viral strains used in this study. The low detection limit was determined as 2.2-22 copies/μL (corresponding to 0.5-6.8 fg/μL DNA template) on plasmid constructs containing viral fragments. The intra-assay and inter-assay variances (CV%) were low that ranged from 2.5 to 5.4 % and 4.1 to 7.6 %, respectively. The assay was applied to test field samples and detected single and mixed viral infections. The detection rate was higher than that of uniplex conventional PCR and RT-PCR methods. The detection of PRRSV by the bead-based multiplex assay was comparable with a commercially available real time RT-PCR kit. The test procedure on purified DNA or RNA samples could be completed within 2 h. In conclusion, the bead-based suspension array presented here proved to be a high-throughput practical tool that provided highly specific and sensitive identification of single and multiple infections of five major viruses in pigs and boar semen. PMID:25557628

  5. Analysis of microseismic activity detected by the WIZARD array, Alpine Fault, New Zealand

    NASA Astrophysics Data System (ADS)

    Feenstra, J. P.; Roecker, S. W.; Thurber, C. H.; Lord, N.; O'Brien, G.; Pesicek, J. D.; Townend, J.; Bannister, S. C.

    2012-12-01

    A primary goal for the UW-Madison-RPI WIZARD array is the characterization of background seismicity around the Deep Fault Drilling Project (DFDP) site on the Alpine Fault, South Island, New Zealand. The WIZARD array consists of 20 stations, half broadband, deployed for a planned 2-year period around the Whataroa Valley DFDP-2 drill site. Two neighboring arrays, SAMBA (Victoria University of Wellington) to the southwest and ALFA'12 (GNS Science) to the northeast, along with several GeoNet permanent stations, provide broad coverage of the region. The earthquakes that are detected will (1) help to define the geometry of the Alpine Fault and other active faults at depth, (2) provide data for seismic imaging, focal mechanisms, and shear-wave splitting analysis, and (3) enable the assessment of possible changes in seismic activity induced by future fault zone drilling. We are currently analyzing data from the first 2 months of the deployment. Dozens of nearby earthquakes (S-P time of up to a few seconds) have been detected, far more than are in the New Zealand GeoNET catalog. This is expected because the magnitude completion level of the GeoNet seismometer network is around 2.5 in the Whataroa region, due to a relatively sparse station coverage. In this presentation, we report on earthquake location results for 8 months of WIZARD data, along with focal mechanisms for selected larger events.

  6. Detecting Volcano-Tectonic Earthquakes at the Tatun Volcano Group in Taiwan with Dense Arrays

    NASA Astrophysics Data System (ADS)

    Sun, W. F.; Lin, C. H.; Chang, W. Y.

    2015-12-01

    The Tatun Volcano Group (TVG) is located at the northernmost tip of the island of Taiwan. Although TVG have been erupted 0.1-0.2 Ma ago and are considered being extinct, some recent studies suggest that they are active or dormant volcanos. We perform a systematic detection of volcano-tectonic earthquakes beneath TVG using three dense, small-aperture seismic arrays, which were deployed for six months in 2012. We use broadband frequency-wavenumber beam forming and moving-window grid-search methods to compute array parameters for all nearly continuous data and identify volcano-tectonic earthquakes. We detect much more events than that listed in the TVG volcano-tectonic earthquake catalog, about 50 events per month. Our results suggest that dense array techniques are capable of capturing detailed spatiotemporal evolution of volcano-tectonic earthquake behaviours at TVG, and also help to better understand the source mechanism of the brittle, uppermost part of the crust to the combined effect of the local hydrothermal fluid pressure and the regional stress field in the volcanic environment.

  7. Controlled fabrication of silver nanoneedles array for SERS and their application in rapid detection of narcotics

    NASA Astrophysics Data System (ADS)

    Yang, Yong; Li, Zhi-Yuan; Yamaguchi, Kohei; Tanemura, Masaki; Huang, Zhengren; Jiang, Dongliang; Chen, Yuhui; Zhou, Fei; Nogami, Masayuki

    2012-03-01

    Novel surface-enhanced Raman scattering (SERS) substrates with high SERS-activity are ideal for novel SERS sensors, detectors to detect illicitly sold narcotics and explosives. The key to the wider application of SERS technique is to develop plasmon resonant structure with novel geometries to enhance Raman signals and to control the periodic ordering of these structures over a large area to obtain reproducible Raman enhancement. In this work, a simple Ar+-ion sputtering route has been developed to fabricate silver nanoneedles arrays on silicon substrates for SERS-active substrates to detect trace-level illicitly sold narcotics. These silver nanoneedles possess a very sharp apex with an apex diameter of 15 nm and an apex angle of 20°. The SERS enhancement factor of greater than 1010 was reproducibly achieved by the well-aligned nanoneedles arrays. Furthermore, ketamine hydrochloride molecules, one kind of illicitly sold narcotics, can be detected down to 27 ppb by using our SERS substrate within 3 s, indicating the sensitivity of our SERS substrates for trace amounts of narcotics and that SERS technology can become an important analytical technique in forensic laboratories because it can provide a rapid and nondestructive method for trace detection.

  8. Weapon detection using a wideband millimeter-wave linear array imaging technique

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; McMakin, Douglas L.; Collins, H. D.; Hall, Thomas E.

    1994-03-01

    A wideband millimeter-wave imaging technique has been developed by the Pacific Northwest Laboratory (PNL) for the detection of concealed weapons carried by personnel through high- security areas, such as airports. A practical airport system based on this technique should be capable of real-time image frame rate of 10 to 30 frames per second. This technique, similar to an extremely high-resolution radar system, actively probes the target with millimeter-waves and reconstructs an image from the backscattered phase and amplitude data. The primary goal of the system is the detection of weapons and the placement of the detected weapon on the body. An important additional goal is the identification of detected items, which requires a high resolution imaging technique. An experimental system has been developed at PNL which has gathered millimeter wave imagery from clothed mannequins and human beings carrying concealed weapons. This system is capable of forming images in excess of 1 meter by 2 meters at resolutions on the order of 1 cm, and is capable of scanning in less than 5 seconds. This experimental system could be enhanced to function in real time by eliminating the relatively slow mechanical scan. A sequentially switched linear array of transceiver antennas would allow real-time gathering of the imaging information, since the data would be electronically scanned in the lateral direction and electronically swept in frequency. This allows formation of a 2D image from a 1D array of transceiver antennas.

  9. Controlled fabrication of silver nanoneedles array for SERS and their application in rapid detection of narcotics.

    PubMed

    Yang, Yong; Li, Zhi-Yuan; Yamaguchi, Kohei; Tanemura, Masaki; Huang, Zhengren; Jiang, Dongliang; Chen, Yuhui; Zhou, Fei; Nogami, Masayuki

    2012-04-21

    Novel surface-enhanced Raman scattering (SERS) substrates with high SERS-activity are ideal for novel SERS sensors, detectors to detect illicitly sold narcotics and explosives. The key to the wider application of SERS technique is to develop plasmon resonant structure with novel geometries to enhance Raman signals and to control the periodic ordering of these structures over a large area to obtain reproducible Raman enhancement. In this work, a simple Ar(+)-ion sputtering route has been developed to fabricate silver nanoneedles arrays on silicon substrates for SERS-active substrates to detect trace-level illicitly sold narcotics. These silver nanoneedles possess a very sharp apex with an apex diameter of 15 nm and an apex angle of 20°. The SERS enhancement factor of greater than 10(10) was reproducibly achieved by the well-aligned nanoneedles arrays. Furthermore, ketamine hydrochloride molecules, one kind of illicitly sold narcotics, can be detected down to 27 ppb by using our SERS substrate within 3 s, indicating the sensitivity of our SERS substrates for trace amounts of narcotics and that SERS technology can become an important analytical technique in forensic laboratories because it can provide a rapid and nondestructive method for trace detection. PMID:22410821

  10. Electrochemical detection of methyl nicotinate biomarker using functionalized anodized titania nanotube arrays

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Dhiman; Smith, York R.; Misra, Mano; Mohanty, Swomitra K.

    2015-02-01

    Sensing and detection of volatile organic compounds (VOCs) from exhaled breath is a possible method for early diagnosis of several pulmonary diseases. The use of solid-state TiO2 nanotube array sensors for VOC sensing applications has been of great interest. In this study, titania nanotubular arrays (TNAs) were synthesized through electrochemical anodization and used for the electrochemical detection of methyl nicotinate biomarker vapor. Functionalization of the TNA with cobalt was found to be necessary for methyl nicotinate detection. Titanium dioxide films synthesized through high temperature oxidation and functionalized with cobalt were also compared with cobalt functionalized TNA. The ordered TNA demonstrated itself to be an effective substrate for cobalt deposition and subsequent biomarker detection over thin titanium dioxide films. Surface analysis of the cobalt functionalized TNA by x-ray photoelectron spectroscopy (XPS) studies observed cobalt deposits exist as cobalt hydroxide on the surface. Exposure of the sensor surface to methyl nicotinate vapor results in the reduction of cobalt hydroxide to cobalt metal on the surface. Two mechanisms have been proposed to describe the binding of the nicotinate biomarker to cobalt functionalized TNA consistent with the XPS studies and band theory.

  11. Towards a peptide-based suspension array for the detection of pestivirus antibodies in swine.

    PubMed

    van der Wal, Fimme J; Jelsma, Tinka; Fijten, Helmi; Achterberg, René P; Loeffen, Willie L A

    2016-09-01

    Classical swine fever (CSF) is a highly contagious and lethal disease in swine. Serological tests for the diagnosis of CSF need not only to detect antibodies against CSFV, but also need to differentiate these from antibodies against other pestiviruses. To investigate the possibilities of specific peptide-based serology, various synthetic peptides that represent a well-described linear epitope of the CSFV E2 protein (TAVSPTTLR) were used to test the viability of a peptide-based suspension array for the detection of antibodies against pestiviruses in swine. The results show that N-terminally biotinylated peptides can bind to avidin conjugated beads, and function in detection of the corresponding monoclonal antibody WH303. There are indications that the length of the spacer between epitope and biotin affect the efficiency of the peptide-antibody interaction. A protocol was established that enables probing for antibodies in porcine sera, where neutravidin-blocking of serum and the use of empty control beads for normalization was crucial. With a set of porcine sera with antibodies against various pestiviruses, the proof of concept of a peptide-based suspension array for specific detection of antibodies against pestiviruses in porcine sera was demonstrated. PMID:27166561

  12. Impedance spectroscopy analysis of human odorant binding proteins immobilized on nanopore arrays for biochemical detection.

    PubMed

    Lu, Yanli; Zhang, Diming; Zhang, Qian; Huang, Yixuan; Luo, Senbiao; Yao, Yao; Li, Shuang; Liu, Qingjun

    2016-05-15

    Human odorant-binding proteins (hOBPs) not only can bind and transport odorants in the surrounding environment for sensing smells, but also play important roles in transmitting lots of biomolecules in different organs. Utilizing the properties of hOBPs, an electrochemical biosensor with nanopore array was developed to detect specific biomolecular ligands, such as aldehydes and fatty acids. The highly ordered nanopores of anodic aluminum oxide with diameter of 20-40 nm were fabricated with two-step oxidation. Through 2-carboxyethyl phosphonic acid, hOBPs were self-assembled on nanopores as the sensing membrane. With nanopore arrays, the impedance spectra showed quite different electron transfer processes in the frequency spectra, which could be characterized by the electron transfer resistance and electrical resistance of the porous membrane. Under stimulation of biomolecular ligands, series resistance of nanopores and hOBPs increased and showed a concentration-dependence feature, while the electron transfer resistance hardly changed. The nanopore based biosensor could sensitively detect biological ligands of benzaldehyde, docosahexaenoic acid, and lauric acid, which were closely related to or were potential biomarkers for cancers and other serious diseases. Equipped with hOBPs, the sensor exhibited promising potentials both in odorant and biomolecule detection for olfactory biosensing and in disease diagnosis and evaluation for biochemical detection. PMID:26710343

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

    PubMed Central

    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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Three-dimensional resolution and contrast-enhanced confocal microscopy with array detection.

    PubMed

    Ge, Baoliang; Wang, Yifan; Huang, Yujia; Kuang, Cuifang; Fang, Yue; Xiu, Peng; Rong, Zihao; Liu, Xu

    2016-05-01

    What we believe is a novel method for improving confocal microscopy's resolution and contrast in 3D space is proposed. Based on a conventional confocal microscopy setup, we use an array detector composed of 32 photomultiplier tubes (PMTs) to replace one point-detector, where the location offset of each PMT caused a different effective point spread function (PSF). By applying array detection and the fluorescence emission difference method of an image with a solid PSF and another with a donut-shaped PSF, we can enhance lateral resolution about 27% in real time with only one scan, and improve the axial resolving ability by about 22% simultaneously. Experimental results of both fluorescent beads and living cells are presented to verify the applicability and effectiveness of our method. PMID:27128062

  17. Laser radar range and detection performance for MEMS corner cube retroreflector arrays

    NASA Astrophysics Data System (ADS)

    Grasso, Robert J.; Jost, Steven R.; Smith, M. J.; McDaniel, Robert V.

    2004-01-01

    BAE SYSTEMS reports on a program to characterize the performance of MEMS corner cube retroreflector arrays under laser illumination. These arrays have significant military and commercial application in the areas of: (1) target identification; (2) target tracking; (3) target location; (4) identification friend-or-foe (IFF); (5) parcel tracking, and; (6) search and rescue assistance. BAE SYSTEMS has theoretically determined the feasibility of these devices to learn if sufficient signal-to-noise performance exists to permit a cooperative laser radar sensor to be considered for device location and interrogation. Results indicate that modest power-apertures are required to achieve SNR performance consistent with high probability of detection and low false alarm rates.

  18. Laser radar range and detection performance for MEMS corner cube retroreflector arrays

    NASA Astrophysics Data System (ADS)

    Grasso, Robert J.; Odhner, Jefferson E.; Stewart, Hamilton; McDaniel, Robert V.

    2004-12-01

    BAE SYSTEMS reports on a program to characterize the performance of MEMS corner cube retroreflector arrays under laser illumination. These arrays have significant military and commercial application in the areas of: 1) target identification; 2) target tracking; 3) target location; 4) identification friend-or-foe (IFF); 5) parcel tracking, and; 6) search and rescue assistance. BAE SYSTEMS has theoretically determined the feasibility of these devices to learn if sufficient signal-to-noise performance exists to permit a cooperative laser radar sensor to be considered for device location and interrogation. Results indicate that modest power-apertures are required to achieve SNR performance consistent with high probability of detection and low false alarm rates.

  19. Breath analysis system for early detection of lung diseases based on multi-sensor array

    NASA Astrophysics Data System (ADS)

    Jeon, Jin-Young; Yu, Joon-Boo; Shin, Jeong-Suk; Byun, Hyung-Gi; Lim, Jeong-Ok

    2013-05-01

    Expiratory breath contains various VOCs(Volatile Organic Compounds) produced from the human. When a certain disease exists, the exhalation has specific VOCs which may be generated from diseases. Many researchers have been actively working to find different types of biomarkers which are characteristic for particular diseases. Research regarding the identification of specific diseases from exhalation is still in progress. The aim of this research is to implement early detection of lung disease such as lung cancer and COPD(Chronic Obstructive Pulmonary Disease), which was nominated on the 6th of domestic death rate in 2010, based on multi-sensor array system. The system has been used to acquire sampled expiratory gases data and PCA(Principle Component Analysis) technique was applied to analyze signals from multi-sensor array. Throughout the experimental trials, a clearly distinguishable difference between lung disease patients and healthy controls was found from the measurement and analysis of their respective expiratory gases.

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

    PubMed

    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.

  1. Use of a chemical sensor array for detecting pollutants in domestic wastewater.

    PubMed

    Bourgeois, W; Stuetz, R M

    2002-11-01

    A chemical sensor array (consisting of 8 conducting polymers) was used to continuously monitor for the presence or absence of industrial pollutants in the headspace of wastewater generated from an on-line flow-cell. A domestic wastewater (Cranfield University sewage works) was dosed with diesel to stimulate the presence of an intermittent discharge in a wastewater influent. Response patterns between the sensors were used to detect for the presence of organic compounds in the wastewater. Correlations between the sensor response patterns or fingerprints were also analysed using principal component analysis. The results clearly demonstrate that a chemical sensor array can rapidly identify the presence of organic compounds (such as diesel) in a wastewater matrix and could be further developed to monitor for industrial pollutants at the inlet of a sewage works.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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. Nanopore arrays in a silicon membrane for parallel single-molecule detection: fabrication

    NASA Astrophysics Data System (ADS)

    Schmidt, Torsten; Zhang, Miao; Sychugov, Ilya; Roxhed, Niclas; Linnros, Jan

    2015-08-01

    Solid state nanopores enable translocation and detection of single bio-molecules such as DNA in buffer solutions. Here, sub-10 nm nanopore arrays in silicon membranes were fabricated by using electron-beam lithography to define etch pits and by using a subsequent electrochemical etching step. This approach effectively decouples positioning of the pores and the control of their size, where the pore size essentially results from the anodizing current and time in the etching cell. Nanopores with diameters as small as 7 nm, fully penetrating 300 nm thick membranes, were obtained. The presented fabrication scheme to form large arrays of nanopores is attractive for parallel bio-molecule sensing and DNA sequencing using optical techniques. In particular the signal-to-noise ratio is improved compared to other alternatives such as nitride membranes suffering from a high-luminescence background.

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

    NASA Astrophysics Data System (ADS)

    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.

    PubMed

    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. PMID:22649939

  7. Flow-enhanced detection of biological pathogens using piezoelectric microcantilever arrays

    NASA Astrophysics Data System (ADS)

    McGovern, John-Paul

    The piezoelectric microcantilever sensor (PEMS) is an all-electrical resonant oscillator biosensor system capable of in-situ and label-free detection. With various insulation and antibody immobilization schemes, it is well-suited for sensitive, specific pathogen detection applications with limits of detection on the order of relevant lethal infectious dosages. Initial PEMS implementation demonstrated biodetection of just 36 total Bacillus anthracis (BA) spores in 0.8 ml of liquid. However, concerns of cross reactivity between the antibody and closely related species of the target pathogens casts doubts on the usefulness of antibody-based assays in terms of the specificity of detection. The goal of this thesis is to develop the PEMS as a method for in-situ, label-free, pathogen detection with better limits of detection than current antibody-based methods as well as high sensitivity and specificity, by exploring PEMS array detection and engineered fluidics specificity augmentation. Experimentation in an 8 mm wide channel revealed that optimal discriminatory detection of BA spores among close cousins (B. cereus (BC), thuringiensis (BT) and subtilis (BS)) was achieved at 14 ml/min. At this flow rate, the detection signals of BC, BT, and BS all fell to within the noise level of the sensor, while that of BA was still nearly optimal. Thus, it was deduced that the interaction forces of BC, BT, and BS were 100 pN. Implementation of array sensing systems enabled real-time, redundant biosensor assays and concurrent background determination by a reference PEMS. Consequentially, successful real-time detection of 10 BA spores/ml was achieved, and single Cryptosporidium parvum (CP) oocyst detection at 0.1 oocysts/ml was accomplished with step-wise resonance frequency shifts of 290 Hz and signal to noise ratios (SNR) greater than 5. In a 19 mm wide flow channel, optimal single oocyst detection efficiency was achieved at 2 ml/min. Optimal discrimination of CP from C. muris (CM

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Genome-Wide Structural Variation Detection by Genome Mapping on Nanochannel Arrays

    PubMed Central

    Mak, Angel C. Y.; Lai, Yvonne Y. Y.; Lam, Ernest T.; Kwok, Tsz-Piu; Leung, Alden K. Y.; Poon, Annie; Mostovoy, Yulia; Hastie, Alex R.; Stedman, William; Anantharaman, Thomas; Andrews, Warren; Zhou, Xiang; Pang, Andy W. C.; Dai, Heng; Chu, Catherine; Lin, Chin; Wu, Jacob J. K.; Li, Catherine M. L.; Li, Jing-Woei; Yim, Aldrin K. Y.; Chan, Saki; Sibert, Justin; Džakula, Željko; Cao, Han; Yiu, Siu-Ming; Chan, Ting-Fung; Yip, Kevin Y.; Xiao, Ming; Kwok, Pui-Yan

    2016-01-01

    Comprehensive whole-genome structural variation detection is challenging with current approaches. With diploid cells as DNA source and the presence of numerous repetitive elements, short-read DNA sequencing cannot be used to detect structural variation efficiently. In this report, we show that genome mapping with long, fluorescently labeled DNA molecules imaged on nanochannel arrays can be used for whole-genome structural variation detection without sequencing. While whole-genome haplotyping is not achieved, local phasing (across >150-kb regions) is routine, as molecules from the parental chromosomes are examined separately. In one experiment, we generated genome maps from a trio from the 1000 Genomes Project, compared the maps against that derived from the reference human genome, and identified structural variations that are >5 kb in size. We find that these individuals have many more structural variants than those published, including some with the potential of disrupting gene function or regulation. PMID:26510793

  10. Development and characterization of a microheater array device for real-time DNA mutation detection

    NASA Astrophysics Data System (ADS)

    Williams, Layne; Okandan, Murat; Chagovetz, Alex; Blair, Steve

    2008-02-01

    DNA analysis, specifically single nucleotide polymorphism (SNP) detection, is becoming increasingly important in rapid diagnostics and disease detection. Temperature is often controlled to help speed reaction rates and perform melting of hybridized oligonucleotides. The difference in melting temperatures, Tm, between wild-type and SNP sequences, respectively, to a given probe oligonucleotide, is indicative of the specificity of the reaction. We have characterized Tm's in solution and on a solid substrate of three sequences from known mutations associated with Cystic Fibrosis. Taking advantage of Tm differences, a microheater array device was designed to enable individual temperature control of up to 18 specific hybridization events. The device was fabricated at Sandia National Laboratories using surface micromachining techniques. The microheaters have been characterized using an IR camera at Sandia and show individual temperature control with minimal thermal cross talk. Development of the device as a real-time DNA detection platform, including surface chemistry and associated microfluidics, is described.

  11. Development and characterization of a microheater array device for real-time DNA mutation detection

    NASA Astrophysics Data System (ADS)

    Williams, Layne; Okandan, Murat; Chagovetz, Alex; Blair, Steve

    2008-04-01

    DNA analysis, specifically single nucleotide polymorphism (SNP) detection, is becoming increasingly important in rapid diagnostics and disease detection. Temperature is often controlled to help speed reaction rates and perform melting of hybridized oligonucleotides. The difference in melting temperatures, Tm, between wild-type and SNP sequences, respectively, to a given probe oligonucleotide, is indicative of the specificity of the reaction. We have characterized Tm's in solution and on a solid substrate of three sequences from known mutations associated with Cystic Fibrosis. Taking advantage of Tm differences, a microheater array device was designed to enable individual temperature control of up to 18 specific hybridization events. The device was fabricated at Sandia National Laboratories using surface micromachining techniques. The microheaters have been characterized using an IR camera at Sandia and show individual temperature control with minimal thermal cross talk. Development of the device as a real-time DNA detection platform, including surface chemistry and associated microfluidics, is described.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2016-12-01

    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.

  14. Multifunctional Paper Strip Based on Self-Assembled Interfacial Plasmonic Nanoparticle Arrays for Sensitive SERS Detection.

    PubMed

    Zhang, Kun; Zhao, Jingjing; Xu, Huiying; Li, Yixin; Ji, Ji; Liu, Baohong

    2015-08-01

    A smart and multifunctional paper-based SERS sensing card is generated through patterning self-assembled interfacial arrays of gold nanoparticles (AuNPs) on the tip of an arrow-shaped paper strip. It is found that the closely packed monolayer of AuNPs is evenly distributed on the paper surface, resulting in a multitude of SERS hot spots over the detection zone. The paper card, with its inherent ability to separate and preconcentrate analytes by the capillary force and polarity difference between sample components, was exploited successfully as an integrated platform, allowing for sub-attomolar (50 × 10(-18) M) detection from microliter-volume (10 μL) samples. Furthermore, the simple preparation (lithography-free process), fast detection (<5 min), and low cost (<3 cents) demonstrate that the paper card is a practical and portable sensing interface for wide application in environmental and food analysis. PMID:26186409

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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 after passing a lens 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 about two hundred scattered photons per atom in order to achieve a high reconstruction fidelity of 99.9 %. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium. Furthermore, first investigations suggest that small aberrations of the lens can be post-corrected in imaging processing.

  16. Genome-Wide Structural Variation Detection by Genome Mapping on Nanochannel Arrays.

    PubMed

    Mak, Angel C Y; Lai, Yvonne Y Y; Lam, Ernest T; Kwok, Tsz-Piu; Leung, Alden K Y; Poon, Annie; Mostovoy, Yulia; Hastie, Alex R; Stedman, William; Anantharaman, Thomas; Andrews, Warren; Zhou, Xiang; Pang, Andy W C; Dai, Heng; Chu, Catherine; Lin, Chin; Wu, Jacob J K; Li, Catherine M L; Li, Jing-Woei; Yim, Aldrin K Y; Chan, Saki; Sibert, Justin; Džakula, Željko; Cao, Han; Yiu, Siu-Ming; Chan, Ting-Fung; Yip, Kevin Y; Xiao, Ming; Kwok, Pui-Yan

    2016-01-01

    Comprehensive whole-genome structural variation detection is challenging with current approaches. With diploid cells as DNA source and the presence of numerous repetitive elements, short-read DNA sequencing cannot be used to detect structural variation efficiently. In this report, we show that genome mapping with long, fluorescently labeled DNA molecules imaged on nanochannel arrays can be used for whole-genome structural variation detection without sequencing. While whole-genome haplotyping is not achieved, local phasing (across >150-kb regions) is routine, as molecules from the parental chromosomes are examined separately. In one experiment, we generated genome maps from a trio from the 1000 Genomes Project, compared the maps against that derived from the reference human genome, and identified structural variations that are >5 kb in size. We find that these individuals have many more structural variants than those published, including some with the potential of disrupting gene function or regulation.

  17. Realization of preconditioned Lanczos and conjugate gradient algorithms on optical linear algebra processors.

    PubMed

    Ghosh, A

    1988-08-01

    Lanczos and conjugate gradient algorithms are important in computational linear algebra. In this paper, a parallel pipelined realization of these algorithms on a ring of optical linear algebra processors is described. The flow of data is designed to minimize the idle times of the optical multiprocessor and the redundancy of computations. The effects of optical round-off errors on the solutions obtained by the optical Lanczos and conjugate gradient algorithms are analyzed, and it is shown that optical preconditioning can improve the accuracy of these algorithms substantially. Algorithms for optical preconditioning and results of numerical experiments on solving linear systems of equations arising from partial differential equations are discussed. Since the Lanczos algorithm is used mostly with sparse matrices, a folded storage scheme to represent sparse matrices on spatial light modulators is also described.

  18. Detection Rates for Surveys for Fast Transients with Next Generation Radio Arrays

    NASA Astrophysics Data System (ADS)

    Macquart, Jean-Pierre

    2011-06-01

    We relate the underlying properties of a population of fast radio-emitting transient events to its expected detection rate in a survey of finite sensitivity. The distribution of the distances of the detected events is determined in terms of the population luminosity distribution and survey parameters, for both extragalactic and Galactic populations. The detection rate as a function of Galactic position is examined to identify regions that optimize survey efficiency in a survey whose field of view is limited. The impact of temporal smearing caused by scattering in the interstellar medium has a large and direction-dependent bearing on the detection of impulsive signals, and we present a model for the effects of scattering on the detection rate. We show that the detection rate scales as ΩS -3/2 + δ 0, where Ω is the field of view, S 0 is the minimum detectable flux density, and 0 < δ <= 3/2 for a survey of Galactic transients in which interstellar scattering or the finite volume of the Galaxy is important. We derive formal conditions on the optimal survey strategy to adopt under different circumstances for fast transient surveys on next generation large-element, wide-field arrays, such as ASKAP, LOFAR, the MWA, and the SKA, and show how interstellar scattering and the finite spatial extent of a Galactic population modify the choice of optimal strategy.

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

    PubMed

    Rosenstierne, Maiken W; McLoughlin, Kevin S; Olesen, Majken Lindholm; Papa, Anna; Gardner, Shea N; Engler, Olivier; Plumet, Sebastien; Mirazimi, Ali; Weidmann, Manfred; Niedrig, Matthias; Fomsgaard, Anders; Erlandsson, Lena

    2014-01-01

    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 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 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 of emerging viruses present in both non-clinical and clinical samples using two different microarray data analysis methods. PMID:24963710

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

    PubMed

    Rosenstierne, Maiken W; McLoughlin, Kevin S; Olesen, Majken Lindholm; Papa, Anna; Gardner, Shea N; Engler, Olivier; Plumet, Sebastien; Mirazimi, Ali; Weidmann, Manfred; Niedrig, Matthias; Fomsgaard, Anders; Erlandsson, Lena

    2014-01-01

    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 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 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 of emerging viruses present in both non-clinical and clinical samples using two different microarray data analysis methods.

  1. Sniper detection using a helmet array: first tests in urban environment

    NASA Astrophysics Data System (ADS)

    Hengy, S.; Demezzo, S.; Hamery, P.

    2007-04-01

    The presence of snipers in modern conflicts leads to high insecurity for the soldiers. In order to improve the soldier's protection against this threat, the French German Institute of Saint-Louis (ISL) and Rheinmetall Defence Electronics GmbH (RDE) work together under the hospice of the German MOD to develop a helmet integrated acoustic array for the detection and localization of snipers. This paper summarizes the results obtained during the collaboration between RDE and the ISL concerning the detection and the localization of the Mach and muzzle waves generated by rifle shots. It summarizes the technical choices that have been made and explains the algorithms that have been used in October 2006 in Lehnin (proving ground of the German MOD), where some measurements in an urban environment have been made. The estimation of the distance between the shooter and the arrays is made with one head equipment alone. In the first tests that have been made with the algorithms developed in ISL, more than 2000 shots have been detected and localized successfully in real-time in non-urban environment. No false alarms have been observed. This paper will present the first results that have been obtained in urban environment.

  2. Development of an artificial sensor for hydrodynamic detection inspired by a seal's whisker array.

    PubMed

    Eberhardt, William C; Wakefield, Brendan F; Murphy, Christin T; Casey, Caroline; Shakhsheer, Yousef; Calhoun, Benton H; Reichmuth, Colleen

    2016-01-01

    Nature has shaped effective biological sensory systems to receive complex stimuli generated by organisms moving through water. Similar abilities have not yet been fully developed in artificial systems for underwater detection and monitoring, but such technology would enable valuable applications for military, commercial, and scientific use. We set out to design a fluid motion sensor array inspired by the searching performance of seals, which use their whiskers to find and follow underwater wakes. This sensor prototype, called the Wake Information Detection and Tracking System (WIDTS), features multiple whisker-like elements that respond to hydrodynamic disturbances encountered while moving through water. To develop and test this system, we trained a captive harbor seal (Phoca vitulina) to wear a blindfold while tracking a remote-controlled, propeller-driven submarine. After mastering the tracking task, the seal learned to carry the WIDTS adjacent to its own vibrissal array during active pursuit of the target. Data from the WIDTS sensors describe changes in the deflection angles of the whisker elements as they pass through the hydrodynamic trail left by the submarine. Video performance data show that these detections coincide temporally with WIDTS-wake intersections. Deployment of the sensors on an actively searching seal allowed for the direct comparison of our instrument to the ability of the biological sensory system in a proof-of-concept demonstration. The creation of the WIDTS provides a foundation for instrument development in the field of biomimetic fluid sensor technology. PMID:27580063

  3. Automatic microfluidic fluorescence-array measurement system for detecting organic phosphate.

    PubMed

    Chang, Hsing-Cheng; Lin, Jung-Chin; Lin, Shyan-Lung; Chang, I-Nan; Lin, Chern-Sheng; Chen, Shi-Yao

    2015-01-01

    In this study, an automatic microfluidic fluorescence-array measurement system is developed to detect the concentration of organic phosphate based on the luminol-hydrogen peroxide catalytic fluorescent mechanism. Not only sample quantity and cost can be reduced, but also detection time, accuracy and precision can be improved in the system. The system is composed of a CCD image module, a stepper motor with driver, a microfluidic fluorescence array, a background light elimination module, and a dynamic image-analyzed interface. The pesticides of chlorpyrifos and fenitrothion of organic phosphate are chosen as experimental samples. Only a 2.5 μ l quantity of sample is required to have a fast response time of 1.4 second. Experimental results show that the sensitivities of chlorpyrifos and fenitrothion are 1.88 V/ppm in the range of 0.166 ∼ 10 ppm with averaged error of 1.66% and 0.32 V/ppm in the range of 0.03 ∼ 10 ppm with averaged error of 1.68% respectively. The organophosphorus effective detection range of the developed system covers the legal prescription for pesticide residues.

  4. Plasmonic interferometric sensor arrays for high-performance label-free biomolecular detection.

    PubMed

    Gao, Yongkang; Xin, Zheming; Zeng, Beibei; Gan, Qiaoqiang; Cheng, Xuanhong; Bartoli, Filbert J

    2013-12-21

    A plasmonic interferometric biosensor that consists of arrays of circular aperture-groove nanostructures patterned on a gold film for phase-sensitive biomolecular detection is demonstrated. The phase and amplitude of interfering surface plasmon polaritons (SPPs) in the proposed device can be effectively engineered by structural tuning, providing flexible and efficient control over the plasmon line shape observed through SPP interference. Spectral fringes with high contrast, narrow linewidth, and large amplitude have been experimentally measured and permit the sensitive detection of protein surface coverage as low as 0.4 pg mm(-2). This sensor resolution compares favorably with commercial prism-based surface plasmon resonance systems (0.1 pg mm(-2)) but is achieved here using a significantly simpler collinear transmission geometry, a miniaturized sensor footprint, and a low-cost compact spectrometer. Furthermore, we also demonstrate superior sensor performance using the intensity interrogation method, which can be combined with CCD imaging to upscale our platform to high-throughput array sensing. A novel low-background interferometric sensing scheme yields a high sensing figure of merit (FOM*) of 146 in the visible region, surpassing that of previous plasmonic biosensors and facilitating ultrasensitive high-throughput detection. PMID:24173621

  5. Spike Detection for Large Neural Populations Using High Density Multielectrode Arrays

    PubMed Central

    Muthmann, Jens-Oliver; Amin, Hayder; Sernagor, Evelyne; Maccione, Alessandro; Panas, Dagmara; Berdondini, Luca; Bhalla, Upinder S.; Hennig, Matthias H.

    2015-01-01

    An emerging generation of high-density microelectrode arrays (MEAs) is now capable of recording spiking activity simultaneously from thousands of neurons with closely spaced electrodes. Reliable spike detection and analysis in such recordings is challenging due to the large amount of raw data and the dense sampling of spikes with closely spaced electrodes. Here, we present a highly efficient, online capable spike detection algorithm, and an offline method with improved detection rates, which enables estimation of spatial event locations at a resolution higher than that provided by the array by combining information from multiple electrodes. Data acquired with a 4096 channel MEA from neuronal cultures and the neonatal retina, as well as synthetic data, was used to test and validate these methods. We demonstrate that these algorithms outperform conventional methods due to a better noise estimate and an improved signal-to-noise ratio (SNR) through combining information from multiple electrodes. Finally, we present a new approach for analyzing population activity based on the characterization of the spatio-temporal event profile, which does not require the isolation of single units. Overall, we show how the improved spatial resolution provided by high density, large scale MEAs can be reliably exploited to characterize activity from large neural populations and brain circuits. PMID:26733859

  6. Polyacrylamide gel film immobilized molecular beacon array for single nucleotide mismatch detection.

    PubMed

    Wang, Yijin; Wang, Hong; Gao, Lu; Liu, Heping; Lu, Zuhong; He, Nongyue

    2005-04-01

    We reported polyacrylamide gel immobilized molecular beacon array for single nucleotide mismatch detection in this paper. Molecular beacons are oligonucleotide probes fluorescing upon hybridization to their complementary DNA/RNA targets with excellent sensitivity and high selectivity. The specially designed molecular beacon for immobilization contains a 15 base loop sequence with a 5 base pair stem, a polyT (20 bases) spacer, a 5'-end amino group for immobilization, a fluorescein in the middle of the sequence as the fluorophore, and a 3'-end DABCYL as the quencher. Between the 5'-end amino group and the stem, the polyT is used to minimize disability caused by 5'-end immobilization. The molecular beacon microarray was fabricated by a pin-based spotting robot and the hybridization was investigated by confocal microscope. A real-time hybridization process at room temperature was registered every minute for 20 min after the target solution was pumped into the hybridization cell. The result indicates that a polyacrylamide film coated glass slide provides an ideal solution-like environment for molecular beacon probes. The potential applications of this kind of molecular beacon array are mutation detection, disease mechanisms, disease diagnostics, etc. in a parallel, cost saving, and label-free detection way.

  7. Bacteria detection based on its blockage effect on silicon nanopore array.

    PubMed

    Tang, Yanyan; Li, Zhen; Luo, Qiaohui; Liu, Jingqing; Wu, Jianmin

    2016-05-15

    Bacteria detection plays an important role in the guarantee of food and water safety. This work proposed a new sensing strategy for the rapid detection of bacteria based on its blockage effect on nanopore array, which was prepared from electrochemically etched silicon. With the assistance of microfluidic technology, the nanopore array attached with Escherichia coli antibody can selectively and rapidly capture E. coli bacteria, resulting in the decrease of pore accessibility. The signal of pore blockage can be measured by in-direct Fourier Transformed Reflectometric Interference Spectroscopy (FT-RIS). The pore blockage signal has a linear relationship with the logarithm of bacterial density in aqueous sample within the range from 10(3) to 10(7)cfuml(-1). Due to the specific interaction between the antibody and target bacteria, only the E. coli sample displayed significant pore blockage effect, whereas the non-target bacteria, Nox and P17, almost did not show any pore blockage effect. The strategy established in this work might be pervasively applied in the rapid detection of target bacteria and cell in a label-free manner.

  8. Ultrasensitive Detection of Cancer Biomarkers in the Clinic using a Nanostructured Microfluidic Array

    PubMed Central

    Malhotra, Ruchika; Patel, Vyomesh; Chikkaveeraiah, Bhaskara V.; Munge, Bernard S.; Cheong, Sok Ching; Zain, Rosnah B.; Abraham, Mannil T.; Dey, Dipak K.; Gutkind, J. Silvio; Rusling, James F.

    2012-01-01

    Multiplexed biomarker protein detection holds unrealized promise for clinical cancer diagnostics due to lack of suitable measurement devices and lack of rigorously validated protein panels. Here we report an ultrasensitive electrochemical microfluidic array optimized to measure a four-protein panel of biomarker proteins, and we validate the protein panel for accurate oral cancer diagnostics. Unprecedented ultralow detection into the 5–50 fg mL−1 range was achieved for simultaneous measurement of proteins IL-6, IL-8, VEGF and VEGF-C in diluted serum. The immunoarray achieves high sensitivity in 50 min assays by using off-line protein capture by magnetic beads carrying 400,000 enzyme labels and 120,000 antibodies. After capturing the proteins and washing to inhibit non-specific binding, the beads are magnetically separated and injected into the array for selective capture by antibodies on eight nanostructured sensors. Good correlations with ELISA for protein determinations in conditioned cancer cell media confirmed the accuracy of this approach. Normalized means of the 4-protein levels in 78 oral cancer patient serum samples and 49 controls gave clinical sensitivity 89% and specificity 98% for oral cancer detection, demonstrating high diagnostic utility. The low cost, easily fabricated immunoarray provides a rapid serum test for diagnosis and personalized therapy of oral cancer. The device is readily adaptable to clinical diagnostics of other cancers. PMID:22697359

  9. Case study using arrays of infrasonic microphones to detect and locate meteors and meteorites

    NASA Astrophysics Data System (ADS)

    Bedard, A. J., Jr.; Greene, G. E.

    Infrasonic data, in conjunction with surface and aircraft observations, are used to investigate the acoustic signals related to a fireball sighting that were detected on Apr. 22, 1975 by two infrasonic observatories in Colorado. It is deduced that the acoustic energy originated from an explosive interaction of the object with the atmosphere, at an altitude of about 25 km and at a distance of roughly 250 km from the observatories. It is concluded that the infrasonic microphone arrays involved successfully identified the region of fireball termination.

  10. Attolitre-sized lipid bilayer chamber array for rapid detection of single transporters

    PubMed Central

    Soga, Naoki; Watanabe, Rikiya; Noji, Hiroyuki

    2015-01-01

    We present an attolitre-sized arrayed lipid bilayer chamber system (aL-ALBiC) for rapid and massively parallel single-molecule assay of membrane transporter activity. Because of the small reaction volume (200 aL), the aL-ALBiC performed fast detection of single transporter activity, thereby enhancing the sensitivity, throughput, and accuracy of the analysis. Thus, aL-ALBiC broadens the opportunities for single-molecule analysis of various membrane transporters and can be used in pharmaceutical applications such as drug screening. PMID:26052065

  11. Attolitre-sized lipid bilayer chamber array for rapid detection of single transporters.

    PubMed

    Soga, Naoki; Watanabe, Rikiya; Noji, Hiroyuki

    2015-06-08

    We present an attolitre-sized arrayed lipid bilayer chamber system (aL-ALBiC) for rapid and massively parallel single-molecule assay of membrane transporter activity. Because of the small reaction volume (200 aL), the aL-ALBiC performed fast detection of single transporter activity, thereby enhancing the sensitivity, throughput, and accuracy of the analysis. Thus, aL-ALBiC broadens the opportunities for single-molecule analysis of various membrane transporters and can be used in pharmaceutical applications such as drug screening.

  12. Long range detection of line-array multi-pulsed coding lidar by combining the Accumulation coherence and Subpixel-energy detection method.

    PubMed

    Su, Jinshan; Wang, Yuanqing; Liang, Dongdong

    2015-06-15

    This paper presents a multi-pulsed line-array push broom lidar, the pixel array scale reaches Geiger mode detectors in time-of-flight (TOF) depth imaging: by using time and space correlation between array elements of array avalanche photo detector (APD), light coding technology and a diode pumped solid-state laser with 10kHz repetition rate and 5µJ per pulses. Two signal enhancement methods, accumulation-coherence and high accuracy energy detection were combined improves the decode effect and realizes further long detection range. Experimental results and theory analysis indicating that the retrieval and denoising results of both simulated and real signals demonstrate that our method is practical and effective; what's more, the increasing scale of array sensor and the code bits can further improve system performance. PMID:26193500

  13. Large-Scale Plasmonic nanoCones Array For Spectroscopy Detection.

    PubMed

    Das, Gobind; Battista, Edmondo; Manzo, Gianluigi; Causa, Filippo; Netti, Paolo Antonio; Di Fabrizio, Enzo

    2015-10-28

    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 a Au-based nanoCone array, fabricated by means of direct nanoimprint technique over large area (mm(2)), 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 × 10(5) 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).

  14. Low Frequency Phased Array Application for Crack Detection in Cast Austenitic Piping

    SciTech Connect

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2006-10-01

    As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effec¬tiveness and reliability of ultrasonic testing (UT) as related to the ISI of primary piping components in US commercial nuclear power plants. This paper describes progress, recent developments and results from an assessment of a portion of the work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner’s Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, were used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays were employed in laboratory trials. Results from laboratory studies for assessing detection, localization and length sizing effectiveness are discussed.

  15. Low frequency gravitational wave detection with ground-based atom interferometer arrays

    NASA Astrophysics Data System (ADS)

    Chaibi, W.; Geiger, R.; Canuel, B.; Bertoldi, A.; Landragin, A.; Bouyer, P.

    2016-01-01

    We propose a new detection strategy for gravitational waves (GWs) below a few hertz based on a correlated array of atom interferometers (AIs). Our proposal allows us to reduce the Newtonian noise (NN), which limits all ground based GW detectors below a 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 a factor of 2 could be achieved and tested with existing AI array geometries. Exploiting the correlation properties of the gravity acceleration noise, we show that a tenfold 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 ×10-19/√{Hz } in the 0.3 -3 Hz frequency band can be within reach, with a peak sensitivity of 3 ×10-23/√{Hz } at 2 Hz . Our proposed configuration could extend the observation window of current detectors by a decade and fill the gap between ground-based and space-based instruments.

  16. Real-time Detection of Breast Cancer Cells Using Peptide-functionalized Microcantilever Arrays

    PubMed Central

    Etayash, Hashem; Jiang, Keren; Azmi, Sarfuddin; Thundat, Thomas; Kaur, Kamaljit

    2015-01-01

    Ligand-directed targeting and capturing of cancer cells is a new approach for detecting circulating tumor cells (CTCs). Ligands such as antibodies have been successfully used for capturing cancer cells and an antibody based system (CellSearch®) is currently used clinically to enumerate CTCs. Here we report the use of a peptide moiety in conjunction with a microcantilever array system to selectively detect CTCs resulting from cancer, specifically breast cancer. A sensing microcantilever, functionalized with a breast cancer specific peptide 18-4 (WxEAAYQrFL), showed significant deflection on cancer cell (MCF7 and MDA-MB-231) binding compared to when exposed to noncancerous (MCF10A and HUVEC) cells. The peptide-functionalized microcantilever allowed efficient capture and detection of cancer cells in MCF7 spiked human blood samples emulating CTCs in human blood. A detection limit of 50–100 cancer cells mL−1 from blood samples was achieved with a capture yield of 80% from spiked whole blood samples. The results emphasize the potential of peptide 18-4 as a novel peptide for capturing and detecting cancer cells in conjunction with nanomechanical cantilever platform. The reported peptide-based cantilever platform represents a new analytical approach that can lead to an alternative to the various detection platforms and can be leveraged to further study CTCs. PMID:26434765

  17. PROSPECTS FOR THE DETECTION OF FAST RADIO BURSTS WITH THE MURCHISON WIDEFIELD ARRAY

    SciTech Connect

    Trott, Cathryn M.; Tingay, Steven J.; Wayth, Randall B.

    2013-10-10

    Fast radio bursts (FRBs) are short timescale (<<1 s) astrophysical radio signals, presumed to be a signature of cataclysmic events of extragalactic origin. The discovery of six high-redshift events at ∼1400 MHz from the Parkes radio telescope suggests that FRBs may occur at a high rate across the sky. The Murchison Widefield Array (MWA) operates at low radio frequencies (80-300 MHz) and is expected to detect FRBs due to its large collecting area (∼2500 m{sup 2}) and wide field-of-view (FOV, ∼ 1000 deg{sup 2} at ν = 200 MHz). We compute the expected number of FRB detections for the MWA assuming a source population consistent with the reported detections. Our formalism properly accounts for the frequency-dependence of the antenna primary beam, the MWA system temperature, and unknown spectral index of the source population, for three modes of FRB detection: coherent; incoherent; and fast imaging. We find that the MWA's sensitivity and large FOV combine to provide the expectation of multiple detectable events per week in all modes, potentially making it an excellent high time resolution science instrument. Deviations of the expected number of detections from actual results will provide a strong constraint on the assumptions made for the underlying source population and intervening plasma distribution.

  18. Electrical protein array chips for the detection of staphylococcal virulence factors.

    PubMed

    Quiel, Annett; Jürgen, Britta; Piechotta, Gundula; Le Foll, Anne-Pascale; Ziebandt, Anne-Kathrin; Kohler, Christian; Köster, Daniela; Engelmann, Susanne; Erck, Christian; Hintsche, Rainer; Wehland, Jürgen; Hecker, Michael; Schweder, Thomas

    2010-02-01

    A new approach for the detection of virulence factors of Staphylococcus aureus and Staphylococcus epidermidis using an electrical protein array chip technology is presented. The procedure is based on an enzyme-linked sandwich immunoassay, which includes recognition and binding of virulence factors by specific capture and detection antibodies. Detection of antibody-bound virulence factors is achieved by measuring the electrical current generated by redox recycling of an enzymatically released substance. The current (measured in nanoampere) corresponds to the amount of the target molecule in the analyzed sample. The electrical protein chip allows for a fast detection of Staphylococcus enterotoxin B (SEB) of S. aureus and immunodominant antigen A homologue (IsaA homologue) of S. epidermidis in different liquid matrices. The S. aureus SEB virulence factor could be detected in minimal medium, milk, and urine in a concentration of 1 ng/ml within less than 23 min. Furthermore, a simultaneous detection of SEB of S. aureus and IsaA homologue of S. epidermidis in a single assay could be demonstrated.

  19. Venturi-electrosonic spray ionization cataluminescence sensor array for saccharides detection.

    PubMed

    Han, Jiaying; Han, Feifei; Ouyang, Jin; Li, Quanmin; Na, Na

    2013-08-20

    In this article, a Venturi electrosonic spray ionization (V-ESSI) cataluminescence (CTL) sensor array was reported for discriminating saccharides in solution. Integrating electrosonic spray ionization (ESSI), a liquid system of Venturi self-pumping injection for the CTL reaction, was fabricated for enhancing CTL reactivity of aqueous samples. Comparing with simple Venturi injection by air and Venturi easy ambient sonic-spray ionization without electric assistance (V-EASI), the remarkable enhancement of CTL signals resulted from V-ESSI. This system showed higher cross-reactive CTL responses catalyzed by alkaline earth metal-nanomaterials than other catalysts, giving different signals for a given saccharide on different catalysts and different responses for different saccharides on the same catalyst. Then, a 4 × 2 CTL sensor array was used for obtaining "fingerprints" of distinct CTL response patterns. Analyzed by linear discriminant analysis (LDA), this V-ESSI CTL sensor array not only achieved the well discrimination of different saccharides (99.9% of total variation) but also discriminated four groups of urine sugar-level for urine samples from diabetic patients (98.1% of discrimination accuracy). It had good reproducibility and gave a linear range of 22.5-67558 μg/mL (R > 0.99) for xylose with a detection limit of 7.4 μg/mL on MgO. As a new artificial tongue, this system provided a simple, rapid, low cost, low energy consumption, and environmentally friendly pathway for aqueous sample discrimination. It has dramatically expanded applications of the CTL-based senor array and will be applicable to clinical diagnoses, environment monitoring, industrial controls, food industry, and various marine monitoring. PMID:23859117

  20. Detection of localized retinal malfunction in retinal degeneration model using a multielectrode array system.

    PubMed

    Homma, Kohei; Osakada, Fumitaka; Hirami, Yasuhiko; Jin, Zi-Bing; Mandai, Michiko; Takahashi, Masayo

    2009-07-01

    Light stimulation inhibits the retinal dark current through phototransduction signals in the photoreceptors. Electroretinography (ERG) detects the blockage of the dark current as the a-wave of the ERG. However, standard ERGs represent the summed neural activity of the retina, and information on localized functions cannot be obtained. In this study, we used a multielectrode array (MEA) system and directly recorded the focal activities of the photoreceptors of the retina. Retinas were isolated from dark-adapted rodents and were draped over the electrode array with vitreal surface of the retina on the electrode array. After light stimulation, negative waves were recorded from each electrode. Adding aminobutyric acid, a selective agonist of mGluR6 expressed on ON-bipolar cells, to the media did not block the generation of the responses. The amplitude of the response increased with increasing retinal development. When the retina was locally injured, light-elicited responses were diminished only in the injured areas of the retina. Retinas isolated from rats given N-methyl-N-nitrosourea (MNU) were also tested. In central retinas of MNU-treated rats, the responses were progressively decreased following injection of MNU. In contrast, in the peripheral retinas, amplitude of the responses was relatively retained, consistent with the retinal thickness observed by immunohistochemistry. In conclusion, light-evoked responses were recorded with the MEA system. The MEA system was useful for detecting subtle and focal activation of photoreceptors. This spatial information should be valuable in investigating local functional recovery in therapeutically treated areas, such as in gene transfer or cell transplantation. PMID:19224574

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Direct detection of a BRAF mutation in total RNA from melanoma cells using cantilever arrays

    NASA Astrophysics Data System (ADS)

    Huber, F.; Lang, H. P.; Backmann, N.; Rimoldi, D.; Gerber, Ch.

    2013-02-01

    Malignant melanoma, the deadliest form of skin cancer, is characterized by a predominant mutation in the BRAF gene. Drugs that target tumours carrying this mutation have recently entered the clinic. Accordingly, patients are routinely screened for mutations in this gene to determine whether they can benefit from this type of treatment. The current gold standard for mutation screening uses real-time polymerase chain reaction and sequencing methods. Here we show that an assay based on microcantilever arrays can detect the mutation nanomechanically without amplification in total RNA samples isolated from melanoma cells. The assay is based on a BRAF-specific oligonucleotide probe. We detected mutant BRAF at a concentration of 500 pM in a 50-fold excess of the wild-type sequence. The method was able to distinguish melanoma cells carrying the mutation from wild-type cells using as little as 20 ng µl-1 of RNA material, without prior PCR amplification and use of labels.

  3. Zinc Nanoparticles-equipped Bioelectronic Nose Using a Microelectrode Array for Odorant Detection.

    PubMed

    Zhang, Qian; Zhang, Diming; Li, Nantao; Lu, Yanli; Yao, Yao; Li, Shuang; Liu, Qingjun

    2016-01-01

    Bioelectronic noses, such as olfactory cell- and receptor-based biosensors, have important applications for biomimetic odorant detection in various fields. Here, a nanoparticle-equipped biosensor was designed to record extracellular potentials from olfactory receptor cells effectively. In this research, a microelectrode array (MEA) was combined with olfactory epitheliums as the olfactory biosensor to record electrophysiological signals of receptor cells in the epitheliums. Zinc nanoparticles (NanoZn) were employed along with the biosensor for different kinds of odorant measurements, which improved the electrophysiological responses to odor molecules. The NanoZn-equipped biosensor showed greater performance, such as a higher sensitivity and a larger signal-to-noise ratio, than that without the nanoparticles. Thus, this approach provided a promising method to improve the detecting performance of biosensors based on olfactory cells and receptors, which would bring broad application prospects for bioelectronic noses in environmental monitoring, food analysis, and healthcare diagnosis.

  4. An integrated portable Raman sensor with nanofabricated gold bowtie array substrates for energetics detection

    SciTech Connect

    Abu Hatab, Nahla A; Rouleau, Christopher; Retterer, Scott T; Eres, Gyula; Hatzinger, Paul B.; Gu, Baohua

    2011-01-01

    An integrated field-portable surface enhaned Raman scattering (SERS) sensing system has been developed and evaluated for quantitative analysis of energetics such as perchlorate (ClO4-) and trinitrotoluene (TNT) at environmentally-relevant concentrations and conditions. The detection system consists of a portable Raman spectrometer equipped with an optical fiber probe that is coupled with novel elevated gold bowtie nanostructural arrays as a sensitive and reproducible SERS substrate. Using the standard addition technique, we show that ClO4- and TNT can be quantified at concentrations as low as 0.66 mg/L (or ~6.6 M) and 0.20 mg/L (~0.9 M), respectively, in groundwater samples collected from selected military sites. This research represents the first step toward the development of a field SERS sensor which may permit rapid, in-situ screening and analysis for various applications including national security, chemical, biological and environmental detection.

  5. An integrated portable Raman sensor with nanofabricated gold bowtie array substrates for energetics detection.

    PubMed

    Hatab, Nahla A; Rouleau, C M; Retterer, Scott T; Eres, Gyula; Hatzinger, Paul B; Gu, Baohua

    2011-04-21

    An integrated field-portable surface enhanced Raman scattering (SERS) sensing system has been developed and evaluated for quantitative analysis of energetics such as perchlorate (ClO(4)(-)) and trinitrotoluene (TNT) at environmentally relevant concentrations and conditions. The detection system consists of a portable Raman spectrometer equipped with an optical fiber probe that is coupled with novel elevated gold bowtie nanostructural arrays as a sensitive and reproducible SERS substrate. Using the standard addition technique, we show that ClO(4)(-) and TNT can be quantified at concentrations as low as 0.66 mg L(-1) (or ~6.6 µM) and 0.20 mg L(-1) (~0.9 µM), respectively, in groundwater samples collected from selected military sites. This research represents the first step toward the development of a field SERS sensor which may permit rapid, in situ screening and analysis for various applications including national security, chemical, biological and environmental detection. PMID:21373687

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

    SciTech Connect

    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.

  7. Microsphere Suspension Array Assays for Detection and Differentiation of Hendra and Nipah Viruses

    PubMed Central

    Foord, Adam J.; White, John R.; Colling, Axel; Heine, Hans G.

    2013-01-01

    Microsphere suspension array systems enable the simultaneous fluorescent identification of multiple separate nucleotide targets in a single reaction. We have utilized commercially available oligo-tagged microspheres (Luminex MagPlex-TAG) to construct and evaluate multiplexed assays for the detection and differentiation of Hendra virus (HeV) and Nipah virus (NiV). Both these agents are bat-borne zoonotic paramyxoviruses of increasing concern for veterinary and human health. Assays were developed targeting multiple sites within the nucleoprotein (N) and phosphoprotein (P) encoding genes. The relative specificities and sensitivities of the assays were determined using reference isolates of each virus type, samples from experimentally infected horses, and archival veterinary diagnostic submissions. Results were assessed in direct comparison with an established qPCR. The microsphere array assays achieved unequivocal differentiation of HeV and NiV and the sensitivity of HeV detection was comparable to qPCR, indicating high analytical and diagnostic specificity and sensitivity. PMID:23509705

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

    PubMed Central

    Stoop, Ralph L.; Wipf, Mathias; Müller, Steffen; Bedner, Kristine; Wright, Iain A.; Martin, Colin J.; Constable, Edwin C.; Fanget, Axel; Schönenberger, Christian; Calame, Michel

    2016-01-01

    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. PMID:27164151

  9. Aptamer-based array electrodes for quantitative interferon-γ detection.

    PubMed

    Chen, Yu; Pui, Tze Sian; Kongsuphol, Patthara; Tang, Kum Cheong; Arya, Sunil K

    2014-03-15

    Present work describes the methylene blue tagged thiolated aptamer-modified gold micro-array based biosensor for specific detection of IFN-γ. The microchips with the microelectrode array were fabricated using standard silicon microfabrication technologies, and modified with methylene blue tagged aptamer using standard gold thiol chemistry. Electrodes were characterized and tested using Cyclic Voltammetric (CV) and Square Wave Voltammetry (SQW) measurements in a standard three-electrode format at room temperature. On an aptamer modified electrode, aptamer density was estimated to be about 4.4 × 10(12)molecules/cm(2). In IFN-γ studies, oxidation peak currents were found to decrease and more than 50% signal suppression was achieved at 500 ng/ml. Further, the magnitude of signal suppression was found to be logarithmically proportional to the IFN-γ in the concentration range of 1-500 ng/ml, with a detection limit of 1.3 ng/ml (i.e. 0.8 fmol in used sample volume of 10 µl). Biosensor showed negligible signal changes (5%) in a very high non-specific protein background, while still able to differentiate target protein IFN-γ at 5 ng/ml. The results indicated that our sensor binds selectively to target molecules, and the non-specific binding where adsorption of BSA protein molecules may be effectively omitted from consideration.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

  12. Enhancing surface plasmon detection using template-stripped gold nanoslit arrays on plastic films.

    PubMed

    Lee, Kuang-Li; Chen, Pei-Wen; Wu, Shu-Han; Huang, Jhih-Bin; Yang, Sen-Yeu; Wei, Pei-Kuen

    2012-04-24

    Nanostructure-based sensors are capable of sensitive and label-free detection for biomedical applications. However, high-throughput and low-cost fabrication techniques are the main issues which should be addressed. In this study, chip-based nanostructures for intensity-sensitive detection were fabricated and tested using a thermal-annealing-assisted template-stripping method. Large-area uniform nanoslit arrays with a 500 nm period and various slit widths, from 30 to 165 nm, were made on plastic films. A transverse magnetic-polarized wave in these gold nanostructures generated sharp and asymmetric Fano resonances in transmission spectra. The full width at half-maximum bandwidth decreased with the decrease of the slit width. The narrowest bandwidth was smaller than 10 nm. Compared to nanoslit arrays on glass substrates using electron-beam lithography, the proposed chip has a higher intensity sensitivity up to 10367%/RIU (refractive index unit) and reaches a figure of merit up to 55. The higher intensity sensitivity for the template-stripped nanostructure is attributed to a smoother gold surface and larger grain sizes on the plastic film, which reduces the surface plasmon propagation loss.

  13. LOW-FREQUENCY PHASED-ARRAY METHODS FOR CRACK DETECTION IN CAST AUSTENITIC PIPING COMPONENTS

    SciTech Connect

    Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Diaz, Aaron A.; Doctor, Steven R.

    2008-01-01

    Studies at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, are being conducted to evaluate nondestructive examination (NDE) approaches for inspecting coarse-grained, austenitic stainless steel reactor components. The work provides information to the United States Nuclear Regulatory Commission (NRC) on the utility, effectiveness, limitations, and reliability of advanced inspection techniques for application on safety-related components in commercial nuclear power plants. This paper describes results from recent assessments using a low-frequency phased-array methodology for detecting cracks in cast austenitic piping welds. Piping specimens that contain thermal and mechanical fatigue cracks located adjacent to welds were examined. The specimens have surface geometrical conditions and weld features that simulate portions of primary piping systems in many U.S. pressurized water reactors (PWRs). In addition, segments of vintage centrifugally cast piping were examined to assess inherent acoustic noise and scattering due to grain structures and determine consistency of ultrasonic (UT) responses from varied circumferential locations. The phased-array UT methods were applied from the outside surface of the specimens using automated scanning devices and water coupling, and employed a modified instrument operating between 500 kHz and 1.0 MHz. Composite volumetric images of the specimens were generated. Results from laboratory studies for assessing crack detection and sizing effectiveness are discussed, including acoustic parameters observed in centrifugally cast piping base materials.

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

    PubMed

    Stoop, Ralph L; Wipf, Mathias; Müller, Steffen; Bedner, Kristine; Wright, Iain A; Martin, Colin J; Constable, Edwin C; Fanget, Axel; Schönenberger, Christian; Calame, Michel

    2016-01-01

    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. PMID:27164151

  15. A laboratory-developed TaqMan Array Card for simultaneous detection of 19 enteropathogens.

    PubMed

    Liu, Jie; Gratz, Jean; Amour, Caroline; Kibiki, Gibson; Becker, Stephen; Janaki, Lalitha; Verweij, Jaco J; Taniuchi, Mami; Sobuz, Shihab U; Haque, Rashidul; Haverstick, Doris M; Houpt, Eric R

    2013-02-01

    The TaqMan Array Card (TAC) system is a 384-well singleplex real-time PCR format that has been used to detect multiple infection targets. Here we developed an enteric TaqMan Array Card to detect 19 enteropathogens, including viruses (adenovirus, astrovirus, norovirus GII, rotavirus, and sapovirus), bacteria (Campylobacter jejuni/C. coli, Clostridium difficile, Salmonella, Vibrio cholerae, diarrheagenic Escherichia coli strains including enteroaggregative E. coli [EAEC], enterotoxigenic E. coli [ETEC], enteropathogenic E. coli [EPEC], and Shiga-toxigenic E. coli [STEC]), Shigella/enteroinvasive E. coli (EIEC), protozoa (Cryptosporidium, Giardia lamblia, and Entamoeba histolytica), and helminths (Ascaris lumbricoides and Trichuris trichiura), as well as two extrinsic controls to monitor extraction and amplification efficiency (the bacteriophage MS2 and phocine herpesvirus). Primers and probes were newly designed or adapted from published sources and spotted onto microfluidic cards. Fecal samples were spiked with extrinsic controls, and DNA and RNA were extracted using the QiaAmp Stool DNA minikit and the QuickGene RNA Tissue kit, respectively, and then mixed with Ag-Path-ID One Step real-time reverse transcription-PCR (RT-PCR) reagents and loaded into cards. PCR efficiencies were between 90% and 105%, with linearities of 0.988 to 1. The limit of detection of the assays in the TAC was within a 10-fold difference from the cognate assays performed on plates. Precision testing demonstrated a coefficient of variation of below 5% within a run and 14% between runs. Accuracy was evaluated for 109 selected clinical specimens and revealed an average sensitivity and specificity of 85% and 77%, respectively, compared with conventional methods (including microscopy, culture, and immunoassay) and 98% and 96%, respectively, compared with our laboratory-developed PCR-Luminex assays. This TAC allows fast, accurate, and quantitative detection of a broad spectrum of enteropathogens and

  16. Development of an Oligonucleotide Array for Direct Detection of Fungi in Sputum Samples from Patients with Cystic Fibrosis▿ †

    PubMed Central

    Bouchara, Jean-Phillippe; Hsieh, Hsin Yi; Croquefer, Sabine; Barton, Richard; Marchais, Veronique; Pihet, Marc; Chang, Tsung Chain

    2009-01-01

    Cystic fibrosis (CF) is the most common inherited genetic disease in Caucasian populations. Besides bacteria, many species of fungi may colonize the respiratory tract of these patients, sometimes leading to true respiratory infections. In this study, an oligonucleotide array capable of identifying 20 fungal species was developed to directly detect fungi in the sputum samples of CF patients. Species-specific oligonucleotide probes were designed from the internal transcribed spacer (ITS) regions of the rRNA operon and immobilized on a nylon membrane. The fungal ITS regions were amplified by PCR and hybridized to the array for species identification. The array was validated by testing 182 target strains (strains which we aimed to identify) and 141 nontarget strains (135 species), and a sensitivity of 100% and a specificity of 99.2% were obtained. The validated array was then used for direct detection of fungi in 57 sputum samples from 39 CF patients, and the results were compared to those obtained by culture. For 16 sputum samples, the results obtained by the array corresponded with those obtained by culture. For 33 samples, the array detected more fungal species than culture did, while the reverse was found for eight samples. The accuracy of the array for fungal detection in sputum samples was confirmed (or partially confirmed) in some samples by cloning and resequencing the amplified ITS fragments. The present array is a useful tool for both the simultaneous detection of multiple fungal species present in the sputa of CF patients and the identification of fungi isolated from these patients. PMID:19020057

  17. Detection and classification of gaseous sulfur compounds by solid electrolyte cyclic voltammetry of cermet sensor array.

    PubMed

    Kramer, Kirsten E; Rose-Pehrsson, Susan L; Hammond, Mark H; Tillett, Duane; Streckert, Holger H

    2007-02-12

    Electrochemical sensors composed of a ceramic-metallic (cermet) solid electrolyte are used for the detection of gaseous sulfur compounds SO(2), H(2)S, and CS(2) in a study involving 11 toxic industrial chemical (TIC) compounds. The study examines a sensor array containing four cermet sensors varying in electrode-electrolyte composition, designed to offer selectivity for multiple compounds. The sensors are driven by cyclic voltammetry to produce a current-voltage profile for each analyte. Raw voltammograms are processed by background subtraction of clean air, and the four sensor signals are concatenated to form one vector of points. The high-resolution signal is compressed by wavelet transformation and a probabilistic neural network is used for classification. In this study, training data from one sensor array was used to formulate models which were validated with data from a second sensor array. Of the 11 gases studied, 3 that contained sulfur produced the strongest responses and were successfully analyzed when the remaining compounds were treated as interferents. Analytes were measured from 10 to 200% of their threshold-limited value (TLV) according to the 8-h time weighted average (TWA) exposure limits defined by the National Institute of Occupational Safety and Health (NIOSH). True positive classification rates of 93.3, 96.7, and 76.7% for SO(2), H(2)S, and CS(2), respectively, were achieved for prediction of one sensor unit when a second sensor was used for modeling. True positive rates of 83.3, 90.0, and 90.0% for SO(2), H(2)S, and CS(2), respectively, were achieved for the second sensor unit when the first sensor unit was used for modeling. Most of the misclassifications were for low concentration levels (such 10-25% TLV) in which case the compound was classified as clean air. Between the two sensors, the false positive rates were 2.2% or lower for the three sulfur compounds, 0.9% or lower for the interferents (eight remaining analytes), and 5.8% or lower for

  18. Surface enhanced Raman scattering by graphene-nanosheet-gapped plasmonic nanoparticle arrays for multiplexed DNA detection

    NASA Astrophysics Data System (ADS)

    Duan, Bo; Zhou, Jiajing; Fang, Zheng; Wang, Chenxu; Wang, Xiujuan; Hemond, Harold F.; Chan-Park, Mary B.; Duan, Hongwei

    2015-07-01

    We have developed a new type of surface enhanced Raman scattering (SERS) substrate with thiolated graphene oxide (tGO) nanosheets sandwiched between two layers of closely packed plasmonic nanoparticles. The trilayered substrate is built up through alternative loading of interfacially assembled plasmonic nanoparticle arrays and tGO nanosheets, followed by coating the nanoparticle surfaces with poly(ethylene glycol) (PEG). Here tGO plays multifunctional roles as a 2D scaffold to immobilized interfacially assembled plasmonic nanoparticles, a nanospacer to create SERS-active nanogaps between two layers of nanoparticle arrays, and a molecule harvester to enrich molecules of interest via π-π interaction. In particular, the molecule harvesting capability of the tGO nanospacer and the stealth properties of PEG coating on the plasmonic nanoparticles collectively lead to preferential positioning of selective targets such as aromatic molecules and single-stranded DNA at the SERS-active nanogap hotspots. We have demonstrated that an SERS assay based on the PEGylated trilayered substrate, in combination with magnetic separation, allows for sensitive, multiplexed ``signal-off'' detection of DNA sequences of bacterial pathogens.We have developed a new type of surface enhanced Raman scattering (SERS) substrate with thiolated graphene oxide (tGO) nanosheets sandwiched between two layers of closely packed plasmonic nanoparticles. The trilayered substrate is built up through alternative loading of interfacially assembled plasmonic nanoparticle arrays and tGO nanosheets, followed by coating the nanoparticle surfaces with poly(ethylene glycol) (PEG). Here tGO plays multifunctional roles as a 2D scaffold to immobilized interfacially assembled plasmonic nanoparticles, a nanospacer to create SERS-active nanogaps between two layers of nanoparticle arrays, and a molecule harvester to enrich molecules of interest via π-π interaction. In particular, the molecule harvesting capability of

  19. Pyroelectric IR sensor arrays for fall detection in the older population

    NASA Astrophysics Data System (ADS)

    Sixsmith, A.; Johnson, N.; Whatmore, R.

    2005-09-01

    Uncooled pyroelectric sensor arrays have been studied over many years for their uses in thermal imaging applications. These arrays will only detect changes in IR flux and so systems based upon them are very good at detecting movements of people in the scene without sensing the background, if they are used in staring mode. Relatively-low element count arrays (16 x 16) can be used for a variety of people sensing applications, including people counting (for safety applications), queue monitoring etc. With appropriate signal processing such systems can be also be used for the detection of particular events such as a person falling over. There is a considerable need for automatic fall detection amongst older people, but there are important limitations to some of the current and emerging technologies available for this. Simple sensors, such as 1 or 2 element pyroelectric infra-red sensors provide crude data that is difficult to interpret; the use of devices worn on the person, such as wrist communicator and motion detectors have potential, but are reliant on the person being able and willing to wear the device; video cameras may be seen as intrusive and require considerable human resources to monitor activity while machine-interpretation of camera images is complex and may be difficult in this application area. The use of a pyroelectric thermal array sensor was seen to have a number of potential benefits. The sensor is wall-mounted and does not require the user to wear a device. It enables detailed analysis of a subject's motion to be achieved locally, within the detector, using only a modest processor. This is possible due to the relative ease with which data from the sensor can be interpreted relative to the data generated by alternative sensors such as video devices. In addition to the cost-effectiveness of this solution, it was felt that the lack of detail in the low-level data, together with the elimination of the need to transmit data outside the detector

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:24357010

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

    PubMed

    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.

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

    PubMed Central

    Wang, Jianzhong; Zhang, Guangyue; Shi, Jiadong

    2015-01-01

    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. PMID:26633416

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  9. Insertional Translocation Detected Using FISH Confirmation of Array-Comparative Genomic Hybridization (aCGH) Results

    PubMed Central

    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

    2013-01-01

    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. PMID:20340098

  10. Using Low-Frequency Phased Arrays to Detect Cracks in Cast Austenitic Piping Components

    SciTech Connect

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2005-12-30

    As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address NDE reliability of inservice inspection (ISI) programs, recent studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effec¬tiveness and reliability of ultrasonic testing (UT) and eddy current testing (ET) inspection techniques as related to the ISI of primary piping components in pressurized water reactors (PWRs). This paper describes progress, recent developments and early results from an assessment of a portion of this work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner’s Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, are being used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays are employed in laboratory trials. Results from laboratory studies for assessing detection of thermal and mechanical fatigue cracks in cast stainless steel piping welds are discussed. This work was sponsored by the U.S. Nuclear Regulatory Commission under Contract DE-AC06-76RLO 1830; NRC JCN Y6604; Mr. Wallace Norris, Program Monitor.

  11. 6-Plex microsphere immunoassay with imaging planar array detection for mycotoxins in barley.

    PubMed

    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

  12. Giant magnetoresistive sensor array for sensitive and specific multiplexed food allergen detection.

    PubMed

    Ng, Elaine; Nadeau, Kari C; Wang, Shan X

    2016-06-15

    Current common allergen detection methods, including enzyme-linked immunosorbent assays (ELISAs) and dip-stick methods, do not provide adequate levels of sensitivity and specificity for at-risk allergic patients. A method for performing highly sensitive and specific detection of multiple food allergens is thus imperative as food allergies are becoming increasingly recognized as a major healthcare concern, affecting an estimated 4% of the total population. We demonstrate first instance of sensitive and specific multiplexed detection of major peanut allergens Ara h 1 and Ara h 2, and wheat allergen Gliadin using giant magnetoresistive (GMR) sensor arrays. Commercialized ELISA kits for Ara h 1 and Ara h 2 report limits of detection (LODs) at 31.5 ng/mL and 0.2 ng/mL, respectively. In addition, the 96-well-based ELISA developed in-house for Gliadin was found to have a LOD of 40 ng/mL. Our multiplexed GMR-based assay demonstrates the ability to perform all three assays on the same chip specifically and with sensitivities at LODs about an order of magnitude lower than those of 96-well-based ELISAs. LODs of GMR-based assays developed for Ara h 1, Ara h 2, and Gliadin were 7.0 ng/mL, 0.2 ng/mL, and 1.5 ng/mL, respectively, with little to no cross-reactivity. These LODs are clinically important as some patients could react strongly against such low allergen levels. Given the limitations of current industrial detection technology, multiplexed GMR-based assays provide a method for highly sensitive and specific simultaneous detection of any combination of food-product allergens, thus protecting allergic patients from life-threatening events, including anaphylaxis, by unintentional consumption.

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

    PubMed

    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.

  14. Giant magnetoresistive sensor array for sensitive and specific multiplexed food allergen detection.

    PubMed

    Ng, Elaine; Nadeau, Kari C; Wang, Shan X

    2016-06-15

    Current common allergen detection methods, including enzyme-linked immunosorbent assays (ELISAs) and dip-stick methods, do not provide adequate levels of sensitivity and specificity for at-risk allergic patients. A method for performing highly sensitive and specific detection of multiple food allergens is thus imperative as food allergies are becoming increasingly recognized as a major healthcare concern, affecting an estimated 4% of the total population. We demonstrate first instance of sensitive and specific multiplexed detection of major peanut allergens Ara h 1 and Ara h 2, and wheat allergen Gliadin using giant magnetoresistive (GMR) sensor arrays. Commercialized ELISA kits for Ara h 1 and Ara h 2 report limits of detection (LODs) at 31.5 ng/mL and 0.2 ng/mL, respectively. In addition, the 96-well-based ELISA developed in-house for Gliadin was found to have a LOD of 40 ng/mL. Our multiplexed GMR-based assay demonstrates the ability to perform all three assays on the same chip specifically and with sensitivities at LODs about an order of magnitude lower than those of 96-well-based ELISAs. LODs of GMR-based assays developed for Ara h 1, Ara h 2, and Gliadin were 7.0 ng/mL, 0.2 ng/mL, and 1.5 ng/mL, respectively, with little to no cross-reactivity. These LODs are clinically important as some patients could react strongly against such low allergen levels. Given the limitations of current industrial detection technology, multiplexed GMR-based assays provide a method for highly sensitive and specific simultaneous detection of any combination of food-product allergens, thus protecting allergic patients from life-threatening events, including anaphylaxis, by unintentional consumption. PMID:26859787

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

    PubMed Central

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

    2010-01-01

    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. PMID:21165155

  16. An impedance biosensor array for label-free detection of multiple antigen-antibody reactions.

    PubMed

    Yu, Xiaobo; Xu, Dawei; Xu, Danke; Lv, Renjie; Liu, Zhihong

    2006-01-01

    An electrochemical impedance biosensor array with protein-modified electrodes was designed and fabricated in this report. To demonstrate its feasibility of the detection of multiple antigen-antibody binding reactions based on a label-free approach, human IgG (hIgG), rat IgG (rIgG), human globin and bovine serum albumin were immobilized, respectively, on the gold electrodes and then the resultant array was incubated with goat anti-hIgG, goat anti-rIgG, anti-human globin antibody and the mixture of three antibodies, respectively. The results indicated that the electron transfer resistance of the electrodes was significantly changed due to formation of the antigen-antibody conjugated layer. In addition, experimental conditions such as the protein concentration for the immobilization and screen were studied and optimized. Furthermore, the surface of various protein-modified electrodes was imaged with atomic force microscopy and the height distribution of protein particles was obtained with the Particle Analysis Software. The relative results were fully in accordance with the ones from the electrochemical impedance spectroscopy.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Murchison Widefield Array Observations of Anomalous Variability: A Serendipitous Night-time Detection of Interplanetary Scintillation

    NASA Astrophysics Data System (ADS)

    Kaplan, D. L.; Tingay, S. J.; Manoharan, P. K.; Macquart, J. P.; Hancock, P.; Morgan, J.; Mitchell, D. A.; Ekers, R. D.; Wayth, R. B.; Trott, C.; Murphy, T.; Oberoi, D.; Cairns, I. H.; Feng, L.; Kudryavtseva, N.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Gaensler, B. M.; Greenhill, L. J.; Hurley Walker, N.; Hazelton, B. J.; Johnston Hollitt, M.; Lonsdale, C. J.; McWhirter, S. R.; Morales, M. F.; Morgan, E.; Ord, S. M.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Webster, R. L.; Williams, A.; Williams, C. L.

    2015-08-01

    We present observations of high-amplitude rapid (2 s) variability toward two bright, compact extragalactic radio sources out of several hundred of the brightest radio sources in one of the 30^\\circ × 30^\\circ Murchison Widefield Array (MWA) Epoch of Reionization fields using the MWA at 155 MHz. After rejecting intrinsic, instrumental, and ionospheric origins we consider the most likely explanation for this variability to be interplanetary scintillation (IPS), likely the result of a large coronal mass ejection propagating from the Sun. This is confirmed by roughly contemporaneous observations with the Ooty Radio Telescope. We see evidence for structure on spatial scales ranging from <1000 to \\gt {10}6 km. The serendipitous night-time nature of these detections illustrates the new regime that the MWA has opened for IPS studies with sensitive night-time, wide-field, low-frequency observations. This regime complements traditional dedicated strategies for observing IPS and can be utilized in real-time to facilitate dedicated follow-up observations. At the same time, it allows large-scale surveys for compact (arcsec) structures in low-frequency radio sources despite the 2\\prime resolution of the array.

  20. Low Frequency Phased Array Techniques for Crack Detection in Cast Austenitic Piping Welds: A Feasibility Study

    SciTech Connect

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2007-01-01

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington have focused on developing and evaluating the reliability of nondestructive testing (NDT) approaches for coarse-grained stainless steel reactor components. The objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the utility, effectiveness and limitation of NDT techniques as related to inservice testing of primary system piping components in pressurized water reactors. We examined cast stainless steel pipe specimens containing thermal and mechanical fatigue cracks located close to the weld roots and having inner and outer diameter surface geometrical conditions that simulate several water reactor primary piping configurations. In addition, segments of vintage centrifugally cast piping were examined to characterize the inherent acoustic noise and scattering caused by grain structures and to determine the consistency of ultrasonic responses when propagating through differing microstructures. Advanced ultrasonic phased array techniques were applied from the outside surface of these specimens using automated scanning devices and water coupling. The phased array approach was implemented with a modified instrument operating at low frequencies, and composite volumetric images of the specimens were generated. Results from laboratory studies for assessing crack detection effectiveness in cast stainless steel as a function of frequency are discussed in this paper.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Modification of Graphene on Ultramicroelectrode Array and Its Application in Detection of Dissolved Oxygen

    PubMed Central

    Wang, Jinfen; Bian, Chao; Tong, Jianhua; Sun, Jizhou; Li, Yang; Hong, Wen; Xia, Shanhong

    2015-01-01

    This paper investigated two different modification methods of graphene (GN) on ultramicroelectrode array (UMEA) and applied the GN modified UMEA for the determination of dissolved oxygen (DO). The UMEAs were fabricated by Micro Electro-Mechanical System (MEMS) technique and the radius of each ultramicroelectrode is 10 μm. GN-NH2 and GN-COOH were modified on UMEA by using self-assembling method. Compared with GN-NH2 modified UMEA, the GN-COOH modified UMEA showed better electrochemical reduction to DO, owing to better dispersing and more active sites. The GN-COOH on UMEA was electroreduced to reduced GN-COOH (rGN-COOH) to increase the conductivity and the catalysis performance. Finally, the palladium nanoparticles/rGN-COOH composite was incorporated into DO microsensor for the detection of DO. PMID:25549176

  3. Statistical Analysis of the Performance of MDL Enumeration for Multiple-Missed Detection in Array Processing

    PubMed Central

    Du, Fei; Li, Yibo; Jin, Shijiu

    2015-01-01

    An accurate performance analysis on the MDL criterion for source enumeration in array processing is presented in this paper. The enumeration results of MDL can be predicted precisely by the proposed procedure via the statistical analysis of the sample eigenvalues, whose distributive properties are investigated with the consideration of their interactions. A novel approach is also developed for the performance evaluation when the source number is underestimated by a number greater than one, which is denoted as “multiple-missed detection”, and the probability of a specific underestimated source number can be estimated by ratio distribution analysis. Simulation results are included to demonstrate the superiority of the presented method over available results and confirm the ability of the proposed approach to perform multiple-missed detection analysis. PMID:26295232

  4. Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles.

    PubMed

    Lee, Sylvanus Y; Amsden, Jason J; Boriskina, Svetlana V; Gopinath, Ashwin; Mitropolous, Alexander; Kaplan, David L; Omenetto, Fiorenzo G; Dal Negro, Luca

    2010-07-01

    Light scattering phenomena in periodic systems have been investigated for decades in optics and photonics. Their classical description relies on Bragg scattering, which gives rise to constructive interference at specific wavelengths along well defined propagation directions, depending on illumination conditions, structural periodicity, and the refractive index of the surrounding medium. In this paper, by engineering multifrequency colorimetric responses in deterministic aperiodic arrays of nanoparticles, we demonstrate significantly enhanced sensitivity to the presence of a single protein monolayer. These structures, which can be readily fabricated by conventional Electron Beam Lithography, sustain highly complex structural resonances that enable a unique optical sensing approach beyond the traditional Bragg scattering with periodic structures. By combining conventional dark-field scattering micro-spectroscopy and simple image correlation analysis, we experimentally demonstrate that deterministic aperiodic surfaces with engineered structural color are capable of detecting, in the visible spectral range, protein layers with thickness of a few tens of Angstroms. PMID:20566892

  5. Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles

    PubMed Central

    Lee, Sylvanus Y.; Amsden, Jason J.; Boriskina, Svetlana V.; Gopinath, Ashwin; Mitropolous, Alexander; Kaplan, David L.; Omenetto, Fiorenzo G.; Negro, Luca Dal

    2010-01-01

    Light scattering phenomena in periodic systems have been investigated for decades in optics and photonics. Their classical description relies on Bragg scattering, which gives rise to constructive interference at specific wavelengths along well defined propagation directions, depending on illumination conditions, structural periodicity, and the refractive index of the surrounding medium. In this paper, by engineering multifrequency colorimetric responses in deterministic aperiodic arrays of nanoparticles, we demonstrate significantly enhanced sensitivity to the presence of a single protein monolayer. These structures, which can be readily fabricated by conventional Electron Beam Lithography, sustain highly complex structural resonances that enable a unique optical sensing approach beyond the traditional Bragg scattering with periodic structures. By combining conventional dark-field scattering micro-spectroscopy and simple image correlation analysis, we experimentally demonstrate that deterministic aperiodic surfaces with engineered structural color are capable of detecting, in the visible spectral range, protein layers with thickness of a few tens of Angstroms. PMID:20566892

  6. Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection.

    PubMed

    Wu, Xiaomu; Gong, Suxuan; Bo, Tao; Liao, Yiping; Liu, Huwei

    2004-12-24

    In this article, the dissociation constants (pKa) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pKa values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pKa values (pKa1 and pKa2) were found for four xanthones while generally the 10 compounds possess the pKa values ranging from 6.4 to 9.2. PMID:15641365

  7. Isolation and detection of single molecules on paramagnetic beads using sequential fluid flows in microfabricated polymer array assemblies.

    PubMed

    Kan, Cheuk W; Rivnak, Andrew J; Campbell, Todd G; Piech, Tomasz; Rissin, David M; Mösl, Matthias; Peterça, Andrej; Niederberger, Hans-Peter; Minnehan, Kaitlin A; Patel, Purvish P; Ferrell, Evan P; Meyer, Raymond E; Chang, Lei; Wilson, David H; Fournier, David R; Duffy, David C

    2012-03-01

    We report a method for isolating individual paramagnetic beads in arrays of femtolitre-sized wells and detecting single enzyme-labeled proteins on these beads using sequential fluid flows in microfabricated polymer array assemblies. Arrays of femtolitre-sized wells were fabricated in cyclic olefin polymer (COP) using injection moulding based on DVD manufacturing. These arrays were bonded to a complementary fluidic structure that was also moulded in COP to create an enclosed device to allow delivery of liquids to the arrays. Enzyme-associated, paramagnetic beads suspended in aqueous solutions of enzyme substrate were delivered fluidically to the array such that one bead per well was loaded by gravity. A fluorocarbon oil was then flowed into the device to remove excess beads from the surface of the array, and to seal and isolate the femtolitre-sized wells containing beads and enzyme substrate. The device was then imaged using standard fluorescence imaging to determine which wells contained single enzyme molecules. The analytical performance of this device as the detector for digital ELISA compared favourably to the standard method, i.e., glass arrays mechanically sealed against a silicone gasket; prostate specific antigen (PSA) could be detected from 0.011 pg mL(-1) up to 100 pg mL(-1). The use of an enclosed fluidic device to isolate beads in single-molecule arrays offers a multitude of advantages for low-cost manufacturing, ease of automation, and instrument development to enable applications in biomarker validation and medical diagnosis. PMID:22179487

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

    PubMed Central

    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

  9. Determination of three anabolic compounds in calf urine by liquid chromatography with photodiode-array detection.

    PubMed

    Martín, Y

    2000-12-01

    A method for the determination of three anabolic hormones (diethylstilbestrol, dienestrol and trenbolone) in calf urine is described. After enzymatic hydrolysis, the samples were cleaned up by C18 solid-phase extraction. Drugs were extracted with hexane and analyzed by isocratic elution on a Discovery RP-Amide C16 5 microns column with photodiode-array detection at 240 and 347 nm. Both retention time and UV spectra were used for identification. Detection limits for the HPLC system were calculated to be 0.3 ng injected for all analytes in the standard mixture. However, for urine samples these limits increased because of the presence of unidentified matrix components. After extraction from urine, the limits of detection for the whole analytical procedure were 5 and 10 ng injected for trenbolone and stilbenes, respectively. The average recoveries of the hormones from spiked samples were in the range 53.1-56.7% with RSD between 11.3 and 14.5% for the whole procedure in the concentration range 25-2.5 ng ml-1.

  10. Detection and localization of single-source gravitational waves with pulsar timing arrays

    NASA Astrophysics Data System (ADS)

    Zhu, X.-J.; Wen, L.; Hobbs, G.; Zhang, Y.; Wang, Y.; Madison, D. R.; Manchester, R. N.; Kerr, M.; Rosado, P. A.; Wang, J.-B.

    2015-05-01

    Pulsar timing arrays (PTAs) can be used to search for very low frequency (10-9-10-7 Hz) gravitational waves (GWs). In this paper, we present a general method for the detection and localization of single-source GWs using PTAs. We demonstrate the effectiveness of this new method for three types of signals: monochromatic waves as expected from individual supermassive binary black holes in circular orbits, GWs from eccentric binaries and GW bursts. We also test its implementation in realistic data sets that include effects such as uneven sampling and heterogeneous data spans and measurement precision. It is shown that our method, which works in the frequency domain, performs as well as published time-domain methods. In particular, we find it equivalent to the Fe-statistic for monochromatic waves. We also discuss the construction of null streams - data streams that have null response to GWs, and the prospect of using null streams as a consistency check in the case of detected GW signals. Finally, we present sensitivities to individual supermassive binary black holes in eccentric orbits. We find that a monochromatic search that is designed for circular binaries can efficiently detect eccentric binaries with both high and low eccentricities, while a harmonic summing technique provides greater sensitivities only for binaries with moderate eccentricities.

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

    PubMed Central

    Bajwa, Avneet; Tan, Shaoqing Tim; Mehta, Ram; Bahreyni, Behraad

    2013-01-01

    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. PMID:23803788

  12. A microfluidic platform with integrated arrays for immunologic assays for biological pathogen detection

    NASA Astrophysics Data System (ADS)

    Klemm, Richard; Becker, Holger; Hlawatsch, Nadine; Julich, Sandra; Miethe, Peter; Moche, Christian; Schattschneider, Sebastian; Tomaso, Herbert; Gärtner, Claudia

    2014-05-01

    The ability to integrate complete assays on a microfluidic chip helps to greatly simplify instrument requirements and allows the use of lab-on-a-chip technology in the field. A core application for such field-portable systems is the detection of pathogens in a CBRN scenario such as permanent monitoring of airborne pathogens, e.g. in subway stations or hospitals etc. An immunological assay was chosen as method for the pathogen identification. The conceptual approach was its realization as a lab-on-a-chip system, enabling an easy handling of the sample in an automated manner. The immunological detection takes place on an antibody array directly implemented in the microfluidic network. Different immobilization strategies will be presented showing the performance of the system. Central elements of the disposable microfluidic device like fluidic interface, turning valves, liquid introduction and waste storage, as well as the architecture of measurement and control fluidic network, will be introduced. Overall process times of about 30 minutes were achieved and assays for the detection of Francisella tularensis and Yersinia pestis are presented. An important feature of the integrated lab-on-a-chip approach is that all waste liquids remain on-chip and contamination risks can be avoided.

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

    NASA Astrophysics Data System (ADS)

    Zhu, X.-J.; Wen, L.; Xiong, J.; Xu, Y.; Wang, Y.; Mohanty, S. D.; Hobbs, G.; Manchester, R. N.

    2016-09-01

    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 per cent); (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 ≳30), it may be possible to improve pulsar distance estimation through GW measurements.

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

    PubMed Central

    Convertino, Annalisa; Mussi, Valentina; Maiolo, Luca

    2016-01-01

    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. PMID:27112197

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    Convertino, Annalisa; Mussi, Valentina; Maiolo, Luca

    2016-04-26

    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.

  17. Detecting Eccentric Supermassive Black Hole Binaries with Pulsar Timing Arrays: Resolvable Source Strategies

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Huerta, E. A.; Gair, J. R.; McWilliams, S. T.

    2016-01-01

    The couplings between supermassive black hole binaries (SMBHBs) 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 (GW) signal enters the pulsar-timing array (PTA) 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 SMBHB system with PTAs. Additionally, we generalize the PTA {{ F }}{{e}}-statistic to eccentric systems, and show that both this statistic and the Bayesian pipeline are robust when studying circular or arbitrarily eccentric systems. We explore how eccentricity influences the detection prospects of single GW sources, as well as the detection penalty incurred by employing a circular waveform template to search for eccentric signals, and conclude by identifying important avenues for future study.

  18. Array-Based Comparative Genomic Hybridization for the Genomewide Detection of Submicroscopic Chromosomal Abnormalities

    PubMed Central

    Vissers, Lisenka E. L. M. ; de Vries, Bert B. A. ; Osoegawa, Kazutoyo ; Janssen, Irene M. ; Feuth, Ton ; Choy, Chik On ; Straatman, Huub ; van der Vliet, Walter ; Huys, Erik H. L. P. G. ; van Rijk, Anke ; Smeets, Dominique ; van Ravenswaaij-Arts, Conny M. A. ; Knoers, Nine V. ; van der Burgt, Ineke ; de Jong, Pieter J. ; Brunner, Han G. ; van Kessel, Ad Geurts ; Schoenmakers, Eric F. P. M. ; Veltman, Joris A. 

    2003-01-01

    Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using ∼3,500 flourescent in situ hybridization–verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome. PMID:14628292

  19. A method for detecting and locating geophysical events using groups of arrays

    NASA Astrophysics Data System (ADS)

    de Groot-Hedlin, Catherine D.; Hedlin, Michael A. H.

    2015-11-01

    We have developed a novel method to detect and locate geophysical events that makes use of any sufficiently dense sensor network. This method is demonstrated using acoustic sensor data collected in 2013 at the USArray Transportable Array (TA). The algorithm applies Delaunay triangulation to divide the sensor network into a mesh of three-element arrays, called triads. Because infrasound waveforms are incoherent between the sensors within each triad, the data are transformed into envelopes, which are cross-correlated to find signals that satisfy a consistency criterion. The propagation azimuth, phase velocity and signal arrival time are computed for each signal. Triads with signals that are consistent with a single source are bundled as an event group. The ensemble of arrival times and azimuths of detected signals within each group are used to locate a common source in space and time. A total of 513 infrasonic stations that were active for part or all of 2013 were divided into over 2000 triads. Low (0.5-2 Hz) and high (2-8 Hz) catalogues of infrasonic events were created for the eastern USA. The low-frequency catalogue includes over 900 events and reveals several highly active source areas on land that correspond with coal mining regions. The high-frequency catalogue includes over 2000 events, with most occurring offshore. Although their cause is not certain, most events are clearly anthropogenic as almost all occur during regular working hours each week. The regions to which the TA is most sensitive vary seasonally, with the direction of reception dependent on the direction of zonal winds. The catalogue has also revealed large acoustic events that may provide useful insight into the nature of long-range infrasound propagation in the atmosphere.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Suspension Array for Multiplex Detection of Eight Fungicide-Resistance Related Alleles in Botrytis cinerea

    PubMed Central

    Zhang, Xin; Xie, Fei; Lv, Baobei; Zhao, Pengxiang; Ma, Xuemei

    2016-01-01

    A simple and high-throughput assay to detect fungicide resistance is required for large-scale monitoring of the emergence of resistant strains of Botrytis cinerea. Using suspension array technology performed on a Bio-Plex 200 System, we developed a single-tube allele-specific primer extension assay that can simultaneously detect eight alleles in one reaction. These eight alleles include E198 and 198A of the β-Tubulin gene (BenA), H272 and 272Y of the Succinate dehydrogenase iron–sulfur subunit gene (SdhB), I365 and 365S of the putative osmosensor histidine kinase gene (BcOS1), and F412 and 412S of the 3-ketoreductase gene (erg27). This assay was first established and optimized with eight plasmid templates containing the DNA sequence variants BenA-E198, BenA-198A, SdhB-H272, SdhB-272Y, BcOS1-I365, BcOS1-365S, erg27-F412, and erg27-412S. Results indicated that none of the probes showed cross-reactivity with one another. The minimum limit of detection for these genotypes was one copy per test. Four mutant plasmids were mixed with 10 ng/μL wild-type genomic DNA in different ratios. Detection sensitivity of mutant loci was 0.45% for BenA-E198A, BcOS1-I365S, and erg27-F412S, and was 4.5% for SdhB-H272Y. A minimum quantity of 0.1 ng of genomic DNA was necessary to obtain reliable results. This is the first reported assay that can simultaneously detect mutations in BenA, SdhB, BcOS1, and erg27. PMID:27708631

  3. Systolic arrays

    SciTech Connect

    Moore, W.R.; McCabe, A.P.H.; Vrquhart, R.B.

    1987-01-01

    Selected Contents of this book are: Efficient Systolic Arrays for the Solution of Toeplitz Systems, The Derivation and Utilization of Bit Level Systolic Array Architectures, an Efficient Systolic Array for Distance Computation Required in a Video-Codec Based Motion-Detection, On Realizations of Least-Squares Estimation and Kalman Filtering by Systolic Arrays, and Comparison of Systolic and SIMD Architectures for Computer Vision Computations.

  4. Design and realization of a contact-less interaction system based on infrared reflection photoelectric detection array

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Lei, Bing; Feng, Ying

    2015-10-01

    Due to the good performance of high sensitivity, quick response and low cost, infrared reflection detection technology is widely used in various fields. In this work, we present a novel contact-less interaction system which is based on infrared reflection detection technology. The system is mainly composed of a Micro Controller Unit (MCU), upper computer and photoelectric detection module. The MCU is utilized to control the photoelectric detection module and to make sure that the sensing unit is lighted one by one in a given order. When the interactive object appears upon the infrared reflection photoelectric detection array, its position information will be ensured and sent to the upper computer through MCU. In this system, every sensing unit is lighted for 1ms, and the detection array includes 8×8 units. It means that the photoelectric detection array will scan 15.6 times per-second. The experimental research results indicate that the factors affecting the detection range including the working current of transmitting diode, modulation frequency, and the reflectivity of the interactive object. When the working current is 10mA, and the modulation frequency is 80 KHz, the system has a detection range of 20 cm. Moreover, efficient modulation and demodulation of optical signal is quite necessary to remove the influence of surrounding light.

  5. Stable, ligand-doped, poly(bis-SorbPC) lipid bilayer arrays for protein binding and detection.

    PubMed

    Joubert, James R; Smith, Kathryn A; Johnson, Erin; Keogh, John P; Wysocki, Vicki H; Gale, Bruce K; Conboy, John C; Saavedra, S Scott

    2009-06-01

    A continuous-flow microspotter was used to generate planar arrays of stabilized bilayers composed of the polymerizable lipid bis-SorbPC and dopant lipids bearing ligands for proteins. Fluorescence microscopy was used to determine the uniformity of the bilayers and to detect protein binding. After UV-initiated polymerization, poly(lipid) bilayer microarrays were air-stable. Cholera toxin subunit b (CTb) bound to an array of poly(lipid) bilayers doped with GM(1), and the extent of binding was correlated to the mole percentage of GM(1) in each spot. A poly(lipid) bilayer array composed of spots doped with GM(1) and spots doped with biotin-DOPE specifically bound CTb and streptavidin to the respective spots from a dissolved mixture of the two proteins. Poly(bis-SorbPC)/GM(1) arrays retained specific CTb binding capacity after multiple regenerations with a protein denaturing solution and also after exposure to air. In addition, these arrays are stable in vacuum, which allows the use of MALDI-TOF mass spectrometry to detect specifically bound CTb. This work demonstrates the considerable potential of poly(lipid) bilayer arrays for high-throughput binding assays and lipidomics studies. PMID:20355927

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Ivanov, A. A.

    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.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. OPTIMAL STRATEGIES FOR CONTINUOUS GRAVITATIONAL WAVE DETECTION IN PULSAR TIMING ARRAYS

    SciTech Connect

    Ellis, J. A.; Siemens, X.; Creighton, J. D. E.

    2012-09-10

    Supermassive black hole binaries (SMBHBs) are expected to emit a continuous gravitational wave signal in the pulsar timing array (PTA) frequency band (10{sup -9} to 10{sup -7} Hz). The development of data analysis techniques aimed at efficient detection and characterization of these signals is critical to the gravitational wave detection effort. In this paper, we leverage methods developed for LIGO continuous wave gravitational searches and explore the use of the F-statistic for such searches in pulsar timing data. Babak and Sesana have used this approach in the context of PTAs to show that one can resolve multiple SMBHB sources in the sky. Our work improves on several aspects of prior continuous wave search methods developed for PTA data analysis. The algorithm is implemented fully in the time domain, which naturally deals with the irregular sampling typical of PTA data and avoids spectral leakage problems associated with frequency domain methods. We take into account the fitting of the timing model and have generalized our approach to deal with both correlated and uncorrelated colored noise sources. We also develop an incoherent detection statistic that maximizes over all pulsar-dependent contributions to the likelihood. To test the effectiveness and sensitivity of our detection statistics, we perform a number of Monte Carlo simulations. We produce sensitivity curves for PTAs of various configurations and outline an implementation of a fully functional data analysis pipeline. Finally, we present a derivation of the likelihood maximized over the gravitational wave phases at the pulsar locations, which results in a vast reduction of the search parameter space.

  11. Detection of Differentially Expressed Genes in an Isogenic Breast Metastasis Model using RNA Arbitrarily Primed-Polymerase Chain Reaction Coupled with Array Hybridization (RAP-Array)

    PubMed Central

    Sloan, Derek D.; Nicholson, Ben; Urquidi, Virginia; Goodison, Steve

    2004-01-01

    To facilitate the study of the mechanisms of breast cancer metastasis we have previously characterized a pair of breast tumor cell lines that originate from the same breast tumor cell line MDA-MB-435, but which have diametrically opposite metastatic capabilities. These cell lines constitute a stable and accessible experimental system for the identification of metastasis-related genes and for the study of their role in the process of metastasis. In this study, we used a combination of RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) fingerprinting and cDNA arrays (here termed “RAP-array”) to identify genes differentially expressed with respect to metastatic phenotype. RAP-PCR was used to generate radioactive probes of reduced complexity for hybridization to nylon membranes containing 588 cDNAs of known identity. Single RAP-PCR fingerprint probes hybridized from 61 (10.4%) to 116 (19.7%) of the filter array targets, with a signal detection overlap of ∼21%. A total of 344 (57%) of the 588 target genes were detected by five single RAP-PCR fingerprints. The advantage of using reduced complexity probes was highlighted by the fact that the combination of RAP probes before hybridization compromised the overall detection rate by up to 40%. Sequential application of RAP-PCR probes allowed the screening of a greater, and an alternative fraction of the transcript population than was achieved with a radiolabeled total cDNA probe. Verification by quantitative reverse transcriptase-PCR confirmed significantly increased expression of keratin 9 (>100-fold) in nonmetastatic breast tumor cells and of CD70 (fivefold) in metastatic cells. The differential expression of keratin 9 and CD70 was maintained between cells grown as primary xenografts in athymic mice. The RAP-array method enabled the detection of genes not revealed using other screening methods and that are candidates for further investigation in the context of metastatic phenotype. PMID:14695344

  12. A clinically applicable approach for detecting spontaneous action potential spikes in amyotrophic lateral sclerosis with a linear electrode array.

    PubMed

    Jahanmiri-Nezhad, Faezeh; Li, Xiaoyan; Barkhaus, Paul E; Rymer, William Z; Zhou, Ping

    2014-02-01

    Examination of spontaneous muscle activity is an important part of the routine electromyogram (EMG) in assessing neuromuscular diseases. The EMG is specifically valuable as a diagnostic test in supporting the diagnosis of amyotrophic lateral sclerosis. High-density surface EMG is a relatively new technique that has until now been used in research but has the potential for clinical application. This study presents a simple high-density surface EMG method for automatic detection of spontaneous action potentials from surface electrode array recordings of patients with amyotrophic lateral sclerosis. To reduce computational complexity while maintaining useful information from the electrode array recording, the multichannel high-density surface EMG was transferred to single-dimensional data by calculating the maximum difference across all channels of the electrode array. A spike detection threshold was then set in the single-dimensional domain to identify the firing times of each spontaneous action potential spike, whereas a spike extraction threshold was used to define the onset and offset of the spontaneous spikes. These data were used to extract the spontaneous spike waveforms from the electrode array EMG. A database of detected spontaneous spikes was thus obtained, including their waveforms, on all channels along with their corresponding firing times. This newly developed method makes use of the information from different channels of the electrode array EMG recording. It also has the primary feature of being simple and fast in implementation, with convenient parameter adjustment and user-computer interaction. Hence, it has good possibilities for clinical application.

  13. High throughput and high yield nanofabrication of precisely designed gold nanohole arrays for fluorescence enhanced detection of biomarkers.

    PubMed

    Wong, Ten It; Han, Shan; Wu, Lin; Wang, Yi; Deng, Jie; Tan, Christina Yuan Ling; Bai, Ping; Loke, Yee Chong; Yang, Xin Da; Tse, Man Siu; Ng, Sum Huan; Zhou, Xiaodong

    2013-06-21

    Fluorescence excitation enhancement by plasmonic nanostructures such as gold nanohole arrays has been a hot topic in biosensing and bioimaging in recent years. However, the high throughput and high yield fabrication of precisely designed metal nanostructures for optimized fluorescence excitation remains a challenge. Our work is the first report combining nanopattern nickel mould fabrication and UV imprinting for gold nanostructure mass fabrication in high yield. We report our successful gold nanohole array mass fabrication on a 4'' glass wafer, by first fabricating a high fidelity nickel mould, then using the mould for UV nanoimprinting on a polymer coated on the glass, evaporating the gold film on the glass wafer, and lifting off the polymer to obtain a gold nanohole array on the glass. Our optimized process for wafer fabrication can achieve almost 100% yield from nanoimprinting to gold lift-off, while the fabricated nickel mould has >70% defect-free area with the rest having a few scattered defects. In our work, the size and pitch of the gold nanohole array are designed to enhance the fluorescent dye Alexa 647. When the fabricated gold nanohole array is used for prostate specific antigen (PSA) detection by establishing a sandwiched fluorescence assay on the gold surface, a detection limit of 100 pg ml(-1) is achieved, while with a same thickness of gold film, only 1 ng ml(-1) is detected. PMID:23645079

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  16. Feasibility of a portable morphological scene change detection security system for field programmable gate arrays (FPGA)

    NASA Astrophysics Data System (ADS)

    Tickle, Andrew J.; Smith, Jeremy S.; Wu, Q. Henry

    2008-04-01

    In this paper, there is an investigation into the possibility of executing a Morphological Scene Change Detection (MSCD) system on a Field Programmable Gate Array (FPGA), which would allow its set up in virtually any location, with its purpose to detect intruders and raise an alarm to call security personal, and a signal to initial a lockdown of the local area. This paper will include how the system was scaled down from the full building multi-computer system, to an FPGA without losing any functionality using Altera's DSP Builder development tool. Also included is the analysis of the different situations which the system would encounter in the field, and their respective alarm triggering levels, these include indoors, outdoors, close-up, distance, high-brightness, low-light, bad weather, etc. The triggering mechanism is a pixel counter and threshold system, and its adaptive design will be included. All the results shown in this paper, will also be verified by MATLAB m-files running on a full desktop PC, to show that the results obtained from the FPGA based system are accurate.

  17. Two-color excitation system for fluorescence detection in DNA sequencing by capillary array electrophoresis.

    PubMed

    Xue, Gang; Yeung, Edward S

    2002-05-01

    Two computer-controlled galvanometer scanners are adapted for two-dimensional step scanning across a 96-capillary array for laser-induced fluorescence detection. 488 nm and 514 nm laser lines from the same Ar(+) laser were alternately coupled for two-color excitation in each capillary. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries and the excitation wavelengths. Based on the differences in absorption spectra for the dyes, the peak-height ratios in the 488 nm and 514 nm excitation electropherograms were used for peak identification for multiplexed capillary electrophoresis. Successful base calling for 24-capillary DNA sequencing was achieved to 450 bp with 99% accuracy. 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. PMID:12116160

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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.

  20. Impedance biosensor based on interdigitated electrode array for detection of E.coli O157:H7 in food products

    NASA Astrophysics Data System (ADS)

    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.

  1. Experimental demonstration of a multi-target detection technique using an X-band optically steered phased array radar.

    PubMed

    Shi, Nuannuan; Li, Ming; Deng, Ye; Zhang, Lihong; Sun, Shuqian; Tang, Jian; Li, Wei; Zhu, Ninghua

    2016-06-27

    An X-band optically-steered phased array radar is developed to demonstrate high resolution multi-target detection. The beam forming is implemented based on wavelength-swept true time delay (TTD) technique. The beam forming system has a wide direction tuning range of ± 54 degree, low magnitude ripple of ± 0.5 dB and small delay error of 0.13 ps/nm. To further verify performance of the proposed optically-steered phased array radar, three experiments are then carried out to implement the single and multiple target detection. A linearly chirped X-band microwave signal is used as radar signal which is finally compressed at the receiver to improve the detection accuracy. The ranging resolution for multi-target detection is up to 2 cm within the measuring distance over 4 m and the azimuth angle error is less than 4 degree.

  2. Experimental demonstration of a multi-target detection technique using an X-band optically steered phased array radar.

    PubMed

    Shi, Nuannuan; Li, Ming; Deng, Ye; Zhang, Lihong; Sun, Shuqian; Tang, Jian; Li, Wei; Zhu, Ninghua

    2016-06-27

    An X-band optically-steered phased array radar is developed to demonstrate high resolution multi-target detection. The beam forming is implemented based on wavelength-swept true time delay (TTD) technique. The beam forming system has a wide direction tuning range of ± 54 degree, low magnitude ripple of ± 0.5 dB and small delay error of 0.13 ps/nm. To further verify performance of the proposed optically-steered phased array radar, three experiments are then carried out to implement the single and multiple target detection. A linearly chirped X-band microwave signal is used as radar signal which is finally compressed at the receiver to improve the detection accuracy. The ranging resolution for multi-target detection is up to 2 cm within the measuring distance over 4 m and the azimuth angle error is less than 4 degree. PMID:27410597

  3. Comparison of simulated and experimental 3D laser images using a GmAPD array: application to long range detection

    NASA Astrophysics Data System (ADS)

    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.

  4. Detection of Brominated By-Products Using a Sensor Array Based on Nanostructured Thin Films of Conducting Polymers

    PubMed Central

    Carvalho, Eduarda Regina; Filho, Nelson Consolin; Venancio, Everaldo Carlos; Osvaldo, N. O.; Mattoso, Luiz H. C.; Martin-Neto, Ladislau

    2007-01-01

    The detection of the carcinogenic trihalomethanes (THM) in public water supply systems using low-cost equipment has become an essential feature, since these compounds may be generated as by-products of water-treatment processes. Here we report on a sensor array that extends the concept of an “electronic tongue” to detect small amounts of bromoform, bromodichloromethane and dibromochloromethane, with detection limits as low as 0.02 mg L-1. The sensor array was made up of 10 sensing units, in which nanostructured films of conducting and natural polymers were deposited onto gold interdigitated electrodes. The principle of detection was impedance spectroscopy, with measurements carried out in the range between 1 Hz to 1 MHz. Using data at 1 kHz, at which the electrical response varied considerably by changing the analyte, we demonstrated with principal component analysis (PCA) that samples with the 3 brominated trihalomethanes can be distinguished from each other and for various concentrations.

  5. A high performance three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection

    NASA Astrophysics Data System (ADS)

    Xu, Chenlong; Song, Zhiqian; Xiang, Qun; Jin, Jian; Feng, Xinjian

    2016-03-01

    We describe here a high performance oxygen-rich three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection. We demonstrate that its linear detection upper limit is 30 mM, more than 15 times higher than that can be obtained on the normal enzyme-electrode. Notably, the three-phase enzyme electrode output is insensitive to the significant oxygen level fluctuation in analyte solution.We describe here a high performance oxygen-rich three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection. We demonstrate that its linear detection upper limit is 30 mM, more than 15 times higher than that can be obtained on the normal enzyme-electrode. Notably, the three-phase enzyme electrode output is insensitive to the significant oxygen level fluctuation in analyte solution. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08370b

  6. The Distributed Biological Observatory (DBO): A Change Detection Array in the Pacific Arctic Region

    NASA Astrophysics Data System (ADS)

    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

  7. Use of the FilmArray System for Detection of Zaire ebolavirus in a Small Hospital in Bo, Sierra Leone

    PubMed Central

    Ansumana, Rashid; Taitt, Chris R.; Lamin, Joseph M.; Bangura, Umaru; Lahai, Joseph; Mbayo, George; Kanneh, Mohamed B.; Bawo, Ben; Bockarie, Alfred S.; Scullion, Matt; Phillips, Cynthia L.; Horner, Cynthia P.; Jacobsen, Kathryn H.; Stenger, David A.

    2015-01-01

    Laboratories associated with small hospitals often have limited expertise, personnel, and equipment to rapidly identify rare and emerging infectious diseases. We describe the successful use of the FilmArray system for rapid detection of Ebola virus directly from clinical samples in 6 out of 83 tested subjects in a small health care center in Sierra Leone. PMID:25972415

  8. Use of the FilmArray System for Detection of Zaire ebolavirus in a Small Hospital in Bo, Sierra Leone.

    PubMed

    Leski, Tomasz A; Ansumana, Rashid; Taitt, Chris R; Lamin, Joseph M; Bangura, Umaru; Lahai, Joseph; Mbayo, George; Kanneh, Mohamed B; Bawo, Ben; Bockarie, Alfred S; Scullion, Matt; Phillips, Cynthia L; Horner, Cynthia P; Jacobsen, Kathryn H; Stenger, David A

    2015-07-01

    Laboratories associated with small hospitals often have limited expertise, personnel, and equipment to rapidly identify rare and emerging infectious diseases. We describe the successful use of the FilmArray system for rapid detection of Ebola virus directly from clinical samples in 6 out of 83 tested subjects in a small health care center in Sierra Leone. PMID:25972415

  9. Evaluation of the FilmArray® system for detection of Bacillus anthracis, Francisella tularensis and Yersinia pestis

    PubMed Central

    Seiner, DR; Colburn, HA; Baird, C; Bartholomew, RA; Straub, T; Victry, K; Hutchison, JR; Valentine, N; Bruckner-Lea, CJ

    2013-01-01

    Aims To evaluate the sensitivity and specificity of the BioFire Diagnostics FilmArray® system in combination with their 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-neighbours, and live Ba spores were analysed using the FilmArray® Biothreat Panel, a multiplexed PCR-based assay for 17 pathogens and toxins. Sensitivity studies with DNA indicate that the limit of detection is 250 genome equivalents (GEs) per sample or lower. Furthermore, the identification of Ft, Yp or Bacillus species was made in 63 of 72 samples tested at 25 GE or less. With samples containing 25 CFU of Ba Sterne spores, at least one of the two possible Ba markers was identified in all samples tested. We observed no cross-reactivity with near-neighbour DNAs. Conclusions Our results indicate that the FilmArray® Biothreat Panel is a sensitive and selective assay for detecting the genetic signatures of Ba, Ft and Yp. Significance and Impact of the Study The FilmArray® platform is a complete sample-to-answer system, combining sample preparation, PCR and data analysis. This system is particularly suited for biothreat testing where samples need to be analysed for multiple biothreats by operators with limited training. PMID:23279070

  10. A high performance three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection.

    PubMed

    Xu, Chenlong; Song, Zhiqian; Xiang, Qun; Jin, Jian; Feng, Xinjian

    2016-04-14

    We describe here a high performance oxygen-rich three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection. We demonstrate that its linear detection upper limit is 30 mM, more than 15 times higher than that can be obtained on the normal enzyme-electrode. Notably, the three-phase enzyme electrode output is insensitive to the significant oxygen level fluctuation in analyte solution.

  11. A high performance three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection.

    PubMed

    Xu, Chenlong; Song, Zhiqian; Xiang, Qun; Jin, Jian; Feng, Xinjian

    2016-04-14

    We describe here a high performance oxygen-rich three-phase enzyme electrode based on superhydrophobic mesoporous silicon nanowire arrays for glucose detection. We demonstrate that its linear detection upper limit is 30 mM, more than 15 times higher than that can be obtained on the normal enzyme-electrode. Notably, the three-phase enzyme electrode output is insensitive to the significant oxygen level fluctuation in analyte solution. PMID:26983941

  12. Hand-held forward-looking focused array mine detection with plane wave excitation

    NASA Astrophysics Data System (ADS)

    Rappaport, Carey M.; Azevedo, Stephen G.; Rosenbury, Tom; Gough, Jamie; Jin, Dongping

    2000-08-01

    A novel handheld time-domain array GPR antipersonnel mine detection system prototype has been developed. Using an offset paraboloidal reflector antenna to collimate rays form an ultra-wideband feed, the transmitted microwave impulse is concentrated forward, in front of the antenna structure. The resulting wave is a non-uniform plane wave over the portion of ground be investigated, and is incident at 45 degrees to normal. As such, much of the ground reflect wave is directed further forward, away from the operator, the reflector, and the receiving antennas, thereby reducing clutter. However, the wave transmitted into the ground, which interacts with the target, tends to have significant backscatter returning toward the receiving antennas. These receiving antennas are configured in a 2 by 2 array to provide spatial focusing in both along and cross-track directions. This is accomplished by measuring and comparing the backscattered signal at each receiver in the narrow time window between the times when the ground reflected wave passes the receiver and before this wave re-reflects from the reflector components. 2D FDTD simulation of this parabolic reflector transmitter indicates that it generates a beam with a non-uniform planar wavefront, which scatters form rough ground primarily in the forward direction. The wave transmitted into the ground is also planar, propagating at the angle of refraction, and scattering fairly isotropically from a small penetrable target. This system has been built and tested at LLNL, using a very narrow pulse shape. LLNL's Micro-Impulse Radar (MIR) and custom-built wideband antenna elements operate in the 1.5 to 5 GHz range. One particular advantage of using the MIR module is its low cost: an important feature for mine detectors used in developing countries. Preliminary measured data indicates that the surface clutter is indeed reduced relative to the target signal, and that small non-metallic anti-personnel mines can be reliably detected at

  13. Development of a Multiplexed Bead-Based Suspension Array for the Detection and Discrimination of Pospiviroid Plant Pathogens

    PubMed Central

    van Brunschot, Sharon L.; Bergervoet, Jan H. W.; Pagendam, Daniel E.; de Weerdt, Marjanne; Geering, Andrew D. W.; Drenth, André; van der Vlugt, René A. A.

    2014-01-01

    Efficient and reliable diagnostic tools for the routine indexing and certification of clean propagating material are essential for the management of pospiviroid diseases in horticultural crops. This study describes the development of a true multiplexed diagnostic method for the detection and identification of all nine currently recognized pospiviroid species in one assay using Luminex bead-based suspension array technology. In addition, a new data-driven, statistical method is presented for establishing thresholds for positivity for individual assays within multiplexed arrays. When applied to the multiplexed array data generated in this study, the new method was shown to have better control of false positives and false negative results than two other commonly used approaches for setting thresholds. The 11-plex Luminex MagPlex-TAG pospiviroid array described here has a unique hierarchical assay design, incorporating a near-universal assay in addition to nine species-specific assays, and a co-amplified plant internal control assay for quality assurance purposes. All assays of the multiplexed array were shown to be 100% specific, sensitive and reproducible. The multiplexed array described herein is robust, easy to use, displays unambiguous results and has strong potential for use in routine pospiviroid indexing to improve disease management strategies. PMID:24404188

  14. Ordered arrays of Au-nanobowls loaded with Ag-nanoparticles as effective SERS substrates for rapid detection of PCBs

    NASA Astrophysics Data System (ADS)

    Chen, Bensong; Meng, Guowen; Zhou, Fei; Huang, Qing; Zhu, Chuhong; Hu, Xiaoye; Kong, Mingguang

    2014-04-01

    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.

  15. Evaluation and Implementation of FilmArray Version 1.7 for Improved Detection of Adenovirus Respiratory Tract Infection

    PubMed Central

    Lacey, Damon; Huang, Rong; Haag, Crissie

    2013-01-01

    The BioFire FilmArray respiratory panel is a multiplex PCR technology capable of detecting a number of bacteria and viruses that cause respiratory tract infection. The assay is technically simple to perform and provides rapid results, making it an appealing option for physicians and laboratorians. The initial product released by BioFire (version 1.6) was reported to have poor sensitivity for adenovirus detection and was therefore of concern when testing immunocompromised patients. This study evaluates the redesigned FilmArray assay (version 1.7) for detection of adenovirus. In this evaluation, we performed both retrospective and prospective verification studies, as well as a detailed serotype analysis. We found that version 1.7 demonstrated improved adenovirus sensitivity. In retrospective studies, sensitivity improved from 66.6% to 90.5%, and in prospective studies, it improved from 42.7% to 83.3%. In addition, when 39 clinically relevant serotypes were tested, 8 were not detected by version 1.6 and only 1 was not detected by version 1.7. The limit of detection remained the same when tested against serotype 4 but improved by 2 log units for serotype 7. Lastly, turnaround time analyses showed that the FilmArray assay was completed 3 h and 9 min after collection, which was more than a 37-h improvement over the previous multiplex PCR assay performed in our laboratory. PMID:24068007

  16. A novel device based on a fluorescent cross-responsive sensor array for detecting lung cancer related volatile organic compounds.

    PubMed

    Lei, Jin-can; Hou, Chang-jun; Huo, Dan-qun; Luo, Xiao-gang; Bao, Ming-ze; Li, Xian; Yang, Mei; Fa, Huan-bao

    2015-02-01

    In this paper, a novel, simple, rapid, and low-cost detection device for lung cancer related Volatile Organic Compounds (VOCs) was constructed. For this task, a sensor array based on cross-responsive mechanism was designed. A special gas chamber was made to insure sensor array exposed to VOCs sufficiently and evenly, and FLUENT software was used to simulate the performance of the gas chamber. The data collection and processing system was used to detect fluorescent changes of the sensor arrays before and after reaction, and to extract unique patterns of the tested VOCs. Four selected VOCs, p-xylene, styrene, isoprene, and hexanal, were detected by the proposed device. Unsupervised pattern recognition methods, hierarchical cluster analysis and principal component analysis, were used to analyze data. The results showed that the methods could 100% discriminate the four VOCs. What is more, combined with artificial neural network, the correct rate of quantitative detection was up to 100%, and the device obtained responses at concentrations below 50 ppb. In conclusion, the proposed detection device showed excellent selectivity and discrimination ability for the VOCs related to lung cancer. Furthermore, our preliminary study demonstrated that the proposed detection device has brilliant potential application for early clinical diagnosis of lung cancer. PMID:25725887

  17. Validation of a high-throughput immunobead array technique for multiplex detection of three foodborne pathogens in chicken products.

    PubMed

    Charlermroj, Ratthaphol; Makornwattana, Manlika; Grant, Irene R; Elliott, Christopher T; Karoonuthaisiri, Nitsara

    2016-05-01

    This study rigorously evaluated a previously developed immunobead array method to simultaneously detect three important foodborne pathogens, Campylobacter jejuni, Listeria monocytogenes, and Salmonella spp., for its actual application in routine food testing. Due to the limitation of the detection limit of the developed method, an enrichment step was included in this study by using Campylobacter Enrichment Broth for C. jejuni and Universal Pre-enrichment Broth for L. monocytogenes and Salmonella spp.. The findings showed that the immunobead array method was capable of detecting as low as 1CFU of the pathogens spiked in the culture media after being cultured for 24h for all three pathogens. The immunobead array method was further evaluated for its pathogen detection capabilities in ready-to-eat (RTE) and ready-to-cook (RTC) chicken samples and proven to be able to detect as low as 1CFU of the pathogens spiked in the food samples after being cultured for 24h in the case of Salmonella spp., and L. monocytogenes and 48 h in the case of C. jejuni. The method was subsequently validated with three types of chicken products (RTE, n=30; RTC, n=20; raw chicken, n=20) and was found to give the same results as the conventional plating method. Our findings demonstrated that the previously developed immunobead array method could be used for actual food testing with minimal enrichment period of only 52 h, whereas the conventional ISO protocols for the same pathogens take 90-144 h. The immunobead array was therefore an inexpensive, rapid and simple method for the food testing.

  18. Validation of a high-throughput immunobead array technique for multiplex detection of three foodborne pathogens in chicken products.

    PubMed

    Charlermroj, Ratthaphol; Makornwattana, Manlika; Grant, Irene R; Elliott, Christopher T; Karoonuthaisiri, Nitsara

    2016-05-01

    This study rigorously evaluated a previously developed immunobead array method to simultaneously detect three important foodborne pathogens, Campylobacter jejuni, Listeria monocytogenes, and Salmonella spp., for its actual application in routine food testing. Due to the limitation of the detection limit of the developed method, an enrichment step was included in this study by using Campylobacter Enrichment Broth for C. jejuni and Universal Pre-enrichment Broth for L. monocytogenes and Salmonella spp.. The findings showed that the immunobead array method was capable of detecting as low as 1CFU of the pathogens spiked in the culture media after being cultured for 24h for all three pathogens. The immunobead array method was further evaluated for its pathogen detection capabilities in ready-to-eat (RTE) and ready-to-cook (RTC) chicken samples and proven to be able to detect as low as 1CFU of the pathogens spiked in the food samples after being cultured for 24h in the case of Salmonella spp., and L. monocytogenes and 48 h in the case of C. jejuni. The method was subsequently validated with three types of chicken products (RTE, n=30; RTC, n=20; raw chicken, n=20) and was found to give the same results as the conventional plating method. Our findings demonstrated that the previously developed immunobead array method could be used for actual food testing with minimal enrichment period of only 52 h, whereas the conventional ISO protocols for the same pathogens take 90-144 h. The immunobead array was therefore an inexpensive, rapid and simple method for the food testing. PMID:26950032

  19. Label-free electrochemical impedance detection of kinase and phosphatase activities using carbon nanofiber nanoelectrode arrays

    PubMed Central

    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

  20. [HPV genotypes prevalence in México and worldwide detected by Linear Array].

    PubMed

    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.

  1. Identification of natural dyes in archeological Coptic textiles by liquid chromatography with diode array detection.

    PubMed

    Orska-Gawryś, Jowita; Surowiec, Izabella; Kehl, Jerzy; Rejniak, Hanna; Urbaniak-Walczak, Katarzyna; Trojanowicz, Marek

    2003-03-14

    Reversed-phase HPLC with diode-array UV-Vis spectrophotometric detection has been used for identification of natural dyes in extracts from wool and silk fibres from archeological textiles. The examined objects originate from 4th to 12th Century Egypt and belong to the collection of Early Christian Art of the National Museum in Warsaw. Extraction from fibres was carried out with HCl solution containing ethanol or with warm pyridine. As the main individual chemical components of natural dyes, anthraquinone, indigoid and flavonoid dyes including alizarin, purpurin, luteolin, apigenin, carminic acid, ellagic acid, gallic acid, laccaic acids A and B and indigotin were found. For pyridine extracts another mobile phase with an optimized gradient of organic modifier concentration was used. With such an eluent the appearance of double peaks for indigotin and indirubin was eliminated. For acidic extraction of dyes from fibres, ethanol was used. Due to its higher boiling point than methanol it evaporates slower from the extraction solution enabling a more efficient extraction of dyes. PMID:12650256

  2. Experiment on interface separation detection of concrete-filled steel tubular arch bridge using accelerometer array

    NASA Astrophysics Data System (ADS)

    Pan, Shengshan; Zhao, Xuefeng; Zhao, Hailiang; Mao, Jian

    2015-04-01

    Based on the vibration testing principle, and taking the local vibration of steel tube at the interface separation area as the study object, a real-time monitoring and the damage detection method of the interface separation of concrete-filled steel tube by accelerometer array through quantitative transient self-excitation is proposed. The accelerometers are arranged on the steel tube area with or without void respectively, and the signals of accelerometers are collected at the same time and compared under different transient excitation points. The results show that compared with the signal of compact area, the peak value of accelerometer signal at void area increases and attenuation speed slows down obviously, and the spectrum peaks of the void area are much more and disordered and the amplitude increases obviously. whether the input point of transient excitation is on void area or not is irrelevant with qualitative identification results. So the qualitative identification of the interface separation of concrete-filled steel tube based on the signal of acceleration transducer is feasible and valid.

  3. Velocity-resolved Hot Water Emission Detected toward HL Tau with the Submillimeter Array

    NASA Astrophysics Data System (ADS)

    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.

  4. Controllable synthesis of branched hierarchical ZnO nanorod arrays for highly sensitive hydrazine detection

    NASA Astrophysics Data System (ADS)

    Hu, Jie; Zhao, Zhenting; Sun, Yongjiao; Wang, Ying; Li, Pengwei; Zhang, Wendong; Lian, Kun

    2016-02-01

    In this paper, three different kinds of ZnO nanostructures were successfully synthesized on Au/Glass (Au/G) substrate by electrochemical deposition method. The morphology and crystalline structures of the obtained samples were characterized using SEM, XRD and HRTEM. Electrochemical responses of the as-prepared ZnO based sensors to hydrazine in 0.1 M phosphate buffer solution (PBS, pH 7.4) were analyzed by cyclic voltammetry and single-potential amperometry. The results confirmed that the electrochemical performances of ZnO sensors are strongly dependent on the specific surface area. Especially, the branched hierarchical ZnO nanorod arrays shows the highest sensitivity of 5.35 μA μM-1 cm-2, a short response time of 3 s, a low detection limit of 0.08 μM with a linear hydrazine concentration response range from 0.8 μM to 101 μM, and it also exhibits excellent anti-interference, stability and reproducibility abilities, which provide great potential method of ZnO branched hierarchical structures in the development of high-performance electrochemical sensor.

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

    PubMed

    Lu, Wei; Asher, Sanford A; Meng, Zihui; Yan, Zequn; Xue, Min; Qiu, Lili; Yi, Da

    2016-10-01

    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. PMID:27214001

  6. Label-Free Detection of Cardiac Troponin-I Using Carbon Nanofiber Based Nanoelectrode Arrays

    NASA Technical Reports Server (NTRS)

    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.

  7. RNA-Seq Mapping and Detection of Gene Fusions with a Suffix Array Algorithm

    PubMed Central

    Sakarya, Onur; Breu, Heinz; Radovich, Milan; Chen, Yongzhi; Wang, Yulei N.; Barbacioru, Catalin; Utiramerur, Sowmi; Whitley, Penn P.; Brockman, Joel P.; Vatta, Paolo; Zhang, Zheng; Popescu, Liviu; Muller, Matthew W.; Kudlingar, Vidya; Garg, Nriti; Li, Chieh-Yuan; Kong, Benjamin S.; Bodeau, John P.; Nutter, Robert C.; Gu, Jian; Bramlett, Kelli S.; Ichikawa, Jeffrey K.; Hyland, Fiona C.; Siddiqui, Asim S.

    2012-01-01

    High-throughput RNA sequencing enables quantification of transcripts (both known and novel), exon/exon junctions and fusions of exons from different genes. Discovery of gene fusions–particularly those expressed with low abundance– is a challenge with short- and medium-length sequencing reads. To address this challenge, we implemented an RNA-Seq mapping pipeline within the LifeScope software. We introduced new features including filter and junction mapping, annotation-aided pairing rescue and accurate mapping quality values. We combined this pipeline with a Suffix Array Spliced Read (SASR) aligner to detect chimeric transcripts. Performing paired-end RNA-Seq of the breast cancer cell line MCF-7 using the SOLiD system, we called 40 gene fusions among over 120,000 splicing junctions. We validated 36 of these 40 fusions with TaqMan assays, of which 25 were expressed in MCF-7 but not the Human Brain Reference. An intra-chromosomal gene fusion involving the estrogen receptor alpha gene ESR1, and another involving the RPS6KB1 (Ribosomal protein S6 kinase beta-1) were recurrently expressed in a number of breast tumor cell lines and a clinical tumor sample. PMID:22496636

  8. Aircraft Aerodynamic Parameter Detection Using Micro Hot-Film Flow Sensor Array and BP Neural Network Identification

    PubMed Central

    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

  9. Design and characterisation of a thin-film electrode array with shared reference/counter electrodes for electrochemical detection.

    PubMed

    Uludag, Yildiz; Olcer, Zehra; Sagiroglu, Mahmut Samil

    2014-07-15

    In the current study, a novel electrode array and integrated microfluidics have been designed and characterised in order to create a sensor chip which is not only easy, rapid and cheaper to produce but also have a smaller imprint and good electrochemical sensing properties. The current study includes the assessment of the effects of an Au quasi-reference electrode and the use of shared reference/counter electrodes for the array, in order to obtain a small array that can be produced using a fine metal mask. In the study, it is found that when Au is used as the quasi-reference electrode, the arrays with shared reference and counter electrodes result in faster electron transfer kinetics and prevent the potential change with respect to scan rate, and hence is advantageous with respect to conventional electrodes. In addition, the resulting novel electrode array has been shown to result in higher current density (10.52 µA/cm(2); HRP detection assay) and measured diffusion coefficient (14.40×10(-12) cm(2)/s; calculated from the data of cyclic voltammetry with 1mM potassium ferricyanide) with respect to conventional electrodes tested in the study. Using the new electrode arrays, the detection limits obtained from horse radish peroxidase (HRP) and bisphenol A assays were 12.5 ng/ml (2.84×10(-10) M ) and 10 ng/ml (44×10(-9) M), respectively. Performing the HRP detection assay in a flow injection system using array integrated microfluidics provided 25 times lower detection limit (11.36×10(-12) M), although Ti has been used as electrode material instead of Au. In short, incorporation of this new electrode array to lab-on-a-chip or MEMs (micro-electro mechanic systems) technologies may pave the way for easy to use automated biosensing devices that could be used for a variety of applications from diagnostics to environmental monitoring, and studies will continue to move forward in this direction. PMID:24561521

  10. Design and characterisation of a thin-film electrode array with shared reference/counter electrodes for electrochemical detection.

    PubMed

    Uludag, Yildiz; Olcer, Zehra; Sagiroglu, Mahmut Samil

    2014-07-15

    In the current study, a novel electrode array and integrated microfluidics have been designed and characterised in order to create a sensor chip which is not only easy, rapid and cheaper to produce but also have a smaller imprint and good electrochemical sensing properties. The current study includes the assessment of the effects of an Au quasi-reference electrode and the use of shared reference/counter electrodes for the array, in order to obtain a small array that can be produced using a fine metal mask. In the study, it is found that when Au is used as the quasi-reference electrode, the arrays with shared reference and counter electrodes result in faster electron transfer kinetics and prevent the potential change with respect to scan rate, and hence is advantageous with respect to conventional electrodes. In addition, the resulting novel electrode array has been shown to result in higher current density (10.52 µA/cm(2); HRP detection assay) and measured diffusion coefficient (14.40×10(-12) cm(2)/s; calculated from the data of cyclic voltammetry with 1mM potassium ferricyanide) with respect to conventional electrodes tested in the study. Using the new electrode arrays, the detection limits obtained from horse radish peroxidase (HRP) and bisphenol A assays were 12.5 ng/ml (2.84×10(-10) M ) and 10 ng/ml (44×10(-9) M), respectively. Performing the HRP detection assay in a flow injection system using array integrated microfluidics provided 25 times lower detection limit (11.36×10(-12) M), although Ti has been used as electrode material instead of Au. In short, incorporation of this new electrode array to lab-on-a-chip or MEMs (micro-electro mechanic systems) technologies may pave the way for easy to use automated biosensing devices that could be used for a variety of applications from diagnostics to environmental monitoring, and studies will continue to move forward in this direction.

  11. Detection of Solar Wind Disturbances: Mexican Array Radio Telescope IPS Observations at 140 MHz

    NASA Astrophysics Data System (ADS)

    Romero-Hernandez, E.; Gonzalez-Esparza, J. A.; Aguilar-Rodriguez, E.; Ontiveros-Hernandez, V.; Villanueva-Hernandez, P.

    2015-09-01

    The interplanetary scintillation (IPS) technique is a remote-sensing method for monitoring solar-wind perturbations. The Mexican Array Radio Telescope (MEXART) is a single-station instrument operating at 140 MHz, fully dedicated to performing solar-wind studies employing the IPS technique. We report MEXART solar-wind measurements (scintillation indices and solar-wind velocities) using data obtained during the 2013 and 2014 campaigns. These solar-wind measurements were calculated employing a new methodology based on the wavelet transform (WT) function. We report the variation of the scintillation indices versus the heliocentric distance for two IPS sources (3C48 and 3C147). We found different average conditions of the solar-wind density fluctuations in 2013 and 2014. We used the fittings of the radial dependence of the scintillation index to calculate g-indices. Based on the g-index value, we identified 17 events that could be associated with strong compression regions in the solar wind. We present the first ICME identifications in our data. We associated 14 IPS events with preceding CME counterparts by employing white-light observations from the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) spacecraft. We found that most of the IPS events, detected during the solar maximum of Cycle 24 were associated with complex CME events. For the IPS events associated with single CME counterparts, we found a deceleration tendency of the CMEs as they propagate in the interplanetary medium. These results show that the instrument detects solar-wind disturbances, and the WT methodology provides solar-wind information with good accuracy. The MEXART observations will complement solar-wind IPS studies using other frequencies, and the tracking of solar-wind disturbances by other stations located at different longitudes.

  12. An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide.

    PubMed

    Hu, Xiaoye; Zheng, Peng; Meng, Guowen; Huang, Qing; Zhu, Chuhong; Han, Fangming; Huang, Zhulin; Li, Zhongbo; Wang, Zhaoming; Wu, Nianqiang

    2016-09-23

    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. PMID:27528554

  13. X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation

    PubMed Central

    Madrigal, I; Rodríguez-Revenga, L; Armengol, L; González, E; Rodriguez, B; Badenas, C; Sánchez, A; Martínez, F; Guitart, M; Fernández, I; Arranz, JA; Tejada, MI; Pérez-Jurado, LA; Estivill, X; Milà, M

    2007-01-01

    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. PMID:18047645

  14. An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide

    NASA Astrophysics Data System (ADS)

    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.

  15. Colorimetric sensor array with unmodified noble metal nanoparticles for naked-eye detection of proteins and bacteria.

    PubMed

    Li, Dongyang; Dong, Yanhua; Li, Bingyu; Wu, Yayan; Wang, Kai; Zhang, Sichun

    2015-11-21

    Herein we report a novel strategy for the detection and identification of proteins using unmodified noble metal nanoparticles. Five gold nanoparticles (AuNPs) and two silver nanoparticles (AgNPs) with different sizes were utilized as sensing elements to create a colorimetric sensor array. In the presence of proteins, the UV-vis absorbance of the noble metal nanoparticles changed due to the interactions between the protein and nanoparticles, producing distinct absorbance response patterns which can be visually detected by the naked eye. The color pattern of the array is a unique "fingerprints" for each protein sample, which can be differentiated by linear discriminant analysis (LDA). Ten different proteins at concentrations of 0.5, 5 and 50 μM have be successfully discriminated. Moreover, the array was also able to discriminate different bacteria at a concentration of 0.05 OD in 200 μL, as well as cancer cells at the level of 5000 cells in 200 μL. This work demonstrates that an unmodified noble metal nanoparticle-based protein detection array has potential for applications in medical diagnostics.

  16. Final Scientific Report, Integrated Seismic Event Detection and Location by Advanced Array Processing

    SciTech Connect

    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

  17. Resolution and signal-to-noise ratio improvement in confocal fluorescence microscopy using array detection and maximum-likelihood processing

    NASA Astrophysics Data System (ADS)

    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.

  18. Integrated detection of intrinsic fluorophores in live microbial cells using an array of thin film amorphous silicon photodetectors.

    PubMed

    Jóskowiak, A; Stasio, N; Chu, V; Prazeres, D M F; Conde, J P

    2012-01-01

    Two-dimensional fluorescence spectroscopy (2D FS) provides a non-invasive means to assess cell condition without the introduction of changes to the cell environment. The method relies on the measurement of the excitation-emission fluorescence intensity matrix of key intrinsic fluorophores, like aromatic amino acids, enzyme cofactors, and vitamins. Commonly used detection systems are complex, with multiple bandpass filters, and are hard to miniaturize. Here, an amorphous silicon photodetector array system integrated with amorphous silicon-carbon alloy filters designed to detect three key fluorophores - tryptophan (Trp), reduced nicotine adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) - is demonstrated. These intrinsic fluorophores were detected in pure solutions and also in suspended yeast cells. The array system was used to monitor changes in intrinsic fluorophore concentration when a yeast cell solution was subject to a thermal shock stress. PMID:22565094

  19. Parallel detection of harmful algae using reverse transcription polymerase chain reaction labeling coupled with membrane-based DNA array.

    PubMed

    Zhang, Chunyun; Chen, Guofu; Ma, Chaoshuai; Wang, Yuanyuan; Zhang, Baoyu; Wang, Guangce

    2014-03-01

    Harmful algal blooms (HABs) are a global problem, which can cause economic loss to aquaculture industry's and pose a potential threat to human health. More attention must be made on the development of effective detection methods for the causative microalgae. The traditional microscopic examination has many disadvantages, such as low efficiency, inaccuracy, and requires specialized skill in identification and especially is incompetent for parallel analysis of several morphologically similar microalgae to species level at one time. This study aimed at exploring the feasibility of using membrane-based DNA array for parallel detection of several microalgae by selecting five microaglae, including Heterosigma akashiwo, Chaetoceros debilis, Skeletonema costatum, Prorocentrum donghaiense, and Nitzschia closterium as test species. Five species-specific (taxonomic) probes were designed from variable regions of the large subunit ribosomal DNA (LSU rDNA) by visualizing the alignment of LSU rDNA of related species. The specificity of the probes was confirmed by dot blot hybridization. The membrane-based DNA array was prepared by spotting the tailed taxonomic probes onto positively charged nylon membrane. Digoxigenin (Dig) labeling of target molecules was performed by multiple PCR/RT-PCR using RNA/DNA mixture of five microalgae as template. The Dig-labeled amplification products were hybridized with the membrane-based DNA array to produce visible hybridization signal indicating the presence of target algae. Detection sensitivity comparison showed that RT-PCR labeling (RPL) coupled with hybridization was tenfold more sensitive than DNA-PCR-labeling-coupled with hybridization. Finally, the effectiveness of RPL coupled with membrane-based DNA array was validated by testing with simulated and natural water samples, respectively. All of these results indicated that RPL coupled with membrane-based DNA array is specific, simple, and sensitive for parallel detection of microalgae which

  20. Antibody array in a multiwell plate format for the sensitive and multiplexed detection of important plant pathogens.

    PubMed

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Gajanandana, Oraprapai; Elliott, Christopher T; Karoonuthaisiri, Nitsara

    2014-07-15

    The global seed market is considered to be an important industry with a total value of $10,543 million US dollars in 2012. Because plant pathogens such as bacteria and viruses cause a significant economic loss to both producers and exporters, the seed export industry urgently requires rapid, sensitive, and inexpensive testing for the pathogens to prevent disease spreading worldwide. This study developed an antibody array in a multiwell plate format to simultaneously detect four crucial plant pathogens, namely, a bacterial fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), Chilli veinal mottle virus (ChiVMV, potyvirus), Watermelon silver mottle virus (WSMoV, tospovirus serogroup IV), and Melon yellow spot virus (MYSV, tospovirus). The capture antibodies specific to the pathogens were immobilized on each well at preassigned positions by an automatic microarrayer. The antibodies on the arrays specifically captured the corresponding pathogens present in the sample extracts. The presence of pathogens bound on the capture antibodies was subsequently detected by a cocktail of fluorescently conjugated secondary antibodies. The limits of detection of the developed antibody array for the detection of Aac, ChiVMV, WSMoV, and MYSV were 5 × 10(5) CFU/mL, 30 ng/mL, 1000 ng/mL, and 160 ng/mL, respectively, which were very similar to those of the conventional ELISA method. The antibody array in a multiwell plate format accurately detected plant pathogens in single and multiple detections. Moreover, this format enables easy handling of the assay at a higher speed of operation. PMID:24945525

  1. Quantitative detection of DNA labeled with magnetic nanoparticles using arrays of MgO-based magnetic tunnel junction sensors

    NASA Astrophysics Data System (ADS)

    Shen, Weifeng; Schrag, Benaiah D.; Carter, Matthew J.; Xiao, Gang

    2008-07-01

    We have demonstrated the detection of 2.5μM target DNA labeled with 16nm Fe3O4 nanoparticles (NPs) using arrays of magnetic tunnel junction sensors with (001)-oriented MgO barrier layers. A MTJ sensor bridge was designed to detect the presence of magnetic NPs bonded with target DNA. A raw signal of 72μV was obtained using complementary target DNA, as compared with a nonspecific bonding signal of 25μV from noncomplementary control DNA. Our results indicate that the current system's detection limit for analyte DNA is better than 100nM.

  2. Detection of baleen whales on an ocean-bottom seismometer array in the Lau Basin

    NASA Astrophysics Data System (ADS)

    Brodie, D.; Dunn, R.

    2011-12-01

    Long-term deployment of ocean-bottom seismometer arrays provides a unique opportunity for identifying and tracking whales in a manner not usually possible in biological studies. Large baleen whales emit low frequency (>5Hz) sounds called 'calls' or 'songs' that can be detected on either the hydrophone or vertical channel of the instrument at distances in excess of 50 km. The calls are distinct to individual species and even geographical groups among species, and are thought to serve a variety of purposes. Distinct repeating calls can be automatically identified using matched-filter processing, and whales can be located in a manner similar to that of earthquakes. Many baleen whale species are endangered, and little is known about their geographic distribution, population dynamics, and basic behaviors. The Lau back-arc basin, a tectonically active, elongated basin bounded by volcanic shallows, lies in the southwestern Pacific Ocean between Fiji and Tonga. Although whales are known to exist around Fiji and Tonga, little is understood about the population dynamics and migration patterns throughout the basin. Twenty-nine broadband ocean-bottom seismometers deployed in the basin recorded data for approximately ten months during the years 2009-2010. To date, four species of whales have been identified in the data: Blue (one call type), Humpback (two call types, including long-lasting 'songs'), Bryde's (one call type), and Fin whales (three call types). Three as-yet-unknown call types have also been identified. After the calls were identified, idealized spectrograms of the known calls were matched against the entire data set using an auto-detection algorithm. The auto-detection output provides the number of calls and times of year when each call type was recorded. Based on the results, whales migrate seasonally through the basin with some overlapping of species. Initial results also indicate that different species of whales are more common in some parts of the basin than

  3. Parallel acquisition of Raman spectra from a 2D multifocal array using a modulated multifocal detection scheme

    NASA Astrophysics Data System (ADS)

    Kong, Lingbo; Chan, James W.

    2015-03-01

    A major limitation of spontaneous Raman scattering is its intrinsically weak signals, which makes Raman analysis or imaging of biological specimens slow and impractical for many applications. To address this, we report the development of a novel modulated multifocal detection scheme for simultaneous acquisition of full Raman spectra from a 2-D m × n multifocal array. A spatial light modulator (SLM), or a pair of galvo-mirrors, is used to generate m × n laser foci. Raman signals generated within each focus are projected simultaneously into a spectrometer and detected by a CCD camera. The system can resolve the Raman spectra with no crosstalk along the vertical pixels of the CCD camera, e.g., along the entrance slit of the spectrometer. However, there is significant overlap of the spectra in the horizontal pixel direction, e.g., along the dispersion direction. By modulating the excitation multifocal array (illumination modulation) or the emitted Raman signal array (detection modulation), the superimposed Raman spectra of different multifocal patterns are collected. The individual Raman spectrum from each focus is then retrieved from the superimposed spectra using a postacquisition data processing algorithm. This development leads to a significant improvement in the speed of acquiring Raman spectra. We discuss the application of this detection scheme for parallel analysis of individual cells with multifocus laser tweezers Raman spectroscopy (M-LTRS) and for rapid confocal hyperspectral Raman imaging.

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

    PubMed

    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 < 0.001) while allowing for the identification of 18 bacterial species with 91.9% overall accuracy within 2 h of growth 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.

  5. Direct detection of transcription factors in cotyledons during seedling development using sensitive silicon-substrate photonic crystal protein arrays.

    PubMed

    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. PMID:25635113

  6. Development of a membrane-array method for the detection of human intestinal bacteria in fecal samples.

    PubMed

    Wang, R F; Kim, S-J; Robertson, L H; Cerniglia, C E

    2002-10-01

    A membrane-array method was developed for the detection of human intestinal bacteria in fecal samples without using the expensive microarray-arrayer and laser-scanner. The 16S rDNA sequences of 20 predominant human intestinal bacterial species were used to design oligonucleotide probes. Three 40-mer oligonucleotides specific for each bacterial species (total 60 probes) were synthesized and applied to nitrocellulose membranes. Digoxigenin (DIG)-labeled 16S rDNAs were amplified by polymerase chain reaction (PCR) from human fecal samples or pure cultured bacteria using two universal primers, and were hybridized to the membrane-array. Hybridization signals were read by NBT/BCIP color development. The 20 intestinal bacterial species tested were Bacteroides thetaiotaomicron, B. vulgatus, B. fragilis, B. distasonis, Clostridium clostridiiforme, C. leptum, Fusobacterium prausnitzii, Peptostreptococcus productus, Ruminococcus obeum, R. bromii, R. callidus, R. albus, Bifidobacterium longum, B. adolescentis, B. infantis, Eubacterium biforme, E. aerofaciens, Lactobacillus acidophilus,Escherichia coli, and Enterococcus faecium. The two universal primers were able to amplify full size 16S rDNA from all of the 20 bacterial species tested. The hybridization results indicated that the membrane-array method is a reliable technique for the detection of predominant human intestinal bacteria in the fecal samples. The result was also confirmed by using specific PCR methods for these bacteria.

  7. Genome-wide SNP detection, validation, and development of an 8K SNP array for apple.

    PubMed

    Chagné, David; Crowhurst, Ross N; Troggio, Michela; Davey, Mark W; Gilmore, Barbara; Lawley, Cindy; Vanderzande, Stijn; Hellens, Roger P; Kumar, Satish; Cestaro, Alessandro; Velasco, Riccardo; Main, Dorrie; Rees, Jasper D; Iezzoni, Amy; Mockler, Todd; Wilhelm, Larry; Van de Weg, Eric; Gardiner, Susan E; Bassil, Nahla; Peace, Cameron

    2012-01-01

    As high-throughput genetic marker screening systems are essential for a range of genetics studies and plant breeding applications, the International RosBREED SNP Consortium (IRSC) has utilized the Illumina Infinium® II system to develop a medium- to high-throughput SNP screening tool for genome-wide evaluation of allelic variation in apple (Malus×domestica) breeding germplasm. For genome-wide SNP discovery, 27 apple cultivars were chosen to represent worldwide breeding germplasm and re-sequenced at low coverage with the Illumina Genome Analyzer II. Following alignment of these sequences to the whole genome sequence of 'Golden Delicious', SNPs were identified using SoapSNP. A total of 2,113,120 SNPs were detected, corresponding to one SNP to every 288 bp of the genome. The Illumina GoldenGate® assay was then used to validate a subset of 144 SNPs with a range of characteristics, using a set of 160 apple accessions. This validation assay enabled fine-tuning of the final subset of SNPs for the Illumina Infinium® II system. The set of stringent filtering criteria developed allowed choice of a set of SNPs that not only exhibited an even distribution across the apple genome and a range of minor allele frequencies to ensure utility across germplasm, but also were located in putative exonic regions to maximize genotyping success rate. A total of 7867 apple SNPs was established for the IRSC apple 8K SNP array v1, of which 5554 were polymorphic after evaluation in segregating families and a germplasm collection. This publicly available genomics resource will provide an unprecedented resolution of SNP haplotypes, which will enable marker-locus-trait association discovery, description of the genetic architecture of quantitative traits, investigation of genetic variation (neutral and functional), and genomic selection in apple.

  8. High-Precision Dispensing of Nanoliter Biofluids on Glass Pedestal Arrays for Ultrasensitive Biomolecule Detection.

    PubMed

    Chen, Xiaoxiao; Liu, Yang; Xu, QianFeng; Zhu, Jing; Poget, Sébastien F; Lyons, Alan M

    2016-05-01

    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

  9. SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure.

    PubMed

    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.

  10. Rational design of a minimal size sensor array for metal ion detection.

    PubMed

    Palacios, Manuel A; Wang, Zhuo; Montes, Victor A; Zyryanov, Grigory V; Anzenbacher, Pavel

    2008-08-01

    The focus of this study was to demonstrate that, in the luminescent sensors, the signal transduction may possibly be the most important part in the sensing process. Rational design of fluorescent sensor arrays for cations utilizing extended conjugated chromophores attached to 8-hydroxyquinoline is reported. All of the optical sensors utilized in the arrays comprise the same 8-hydroxyquinoline (8-HQ) receptor and various conjugated chromophores to yield a different response to various metal cations. This is because the conjugated chromophores attached to the receptor are partially quenched in their resting state, and upon the cation coordination by the 8-HQ, the resulting metalloquinolinolate complex displays a change in fluorescence. A delicate balance of conjugation, fluorescence enhancement, energy transfer, and a heavy metal quenching effect results in a fingerprint-like pattern of responses for each sensor-cation complex. Principal component analysis (PCA) and linear discriminant analysis (LDA) are used to demonstrate the contribution of individual sensors within the array, information that may be used to design sensor arrays with the smallest number of sensor elements. This approach allows discriminating between 10 cations by as few as two or even one sensor element. Examples of arrays comprising various numbers of sensor elements and their utility in qualitative identification of Ca(2+), Mg(2+), Cd(2+), Hg(2+), Co(2+), Zn(2+), Cu(2+), Ni(2+), Al(3+), and Ga(3+) ions are presented. A two-member array was found to identify 11 analytes with 100% accuracy. Also the best two of the sensors were tested alone and both were found to be able to discriminate among the samples with 99% and 96% accuracy, respectively. To illustrate the utility of this approach to a real-world application, identification of enhanced soft drinks based on their Ca(2+), Mg(2+), and Zn(2+) cation content was performed. The same approach to reducing array elements was used to construct three

  11. Highly specific detection of thrombin using an aptamer-based suspension array and the interaction analysis via microscale thermophoresis.

    PubMed

    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.

  12. Fluorescent polymer sensor array for detection and discrimination of explosives in water.

    PubMed

    Woodka, Marc D; Schnee, Vincent P; Polcha, Michael P

    2010-12-01

    A fluorescent polymer sensor array (FPSA) was made from commercially available fluorescent polymers coated onto glass beads and was tested to assess the ability of the array to discriminate between different analytes in aqueous solution. The array was challenged with exposures to 17 different analytes, including the explosives trinitrotoluene (TNT), tetryl, and RDX, various explosive-related compounds (ERCs), and nonexplosive electron-withdrawing compounds (EWCs). The array exhibited a natural selectivity toward EWCs, while the non-electron-withdrawing explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) produced no response. Response signatures were visualized by principal component analysis (PCA), and classified by linear discriminant analysis (LDA). RDX produced the same response signature as the sampled blanks and was classified accordingly. The array exhibited excellent discrimination toward all other compounds, with the exception of the isomers of nitrotoluene and aminodinitrotoluene. Of particular note was the ability of the array to discriminate between the three isomers of dinitrobenzene. The natural selectivity of the FPSA toward EWCs, plus the ability of the FPSA to discriminate between different EWCs, could be used to design a sensor with a low false alarm rate and an excellent ability to discriminate between explosives and explosive-related compounds. PMID:21069967

  13. Are We There Yet? Time to Detection of Nanohertz Gravitational Waves Based on Pulsar-timing Array Limits

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Vallisneri, M.; Ellis, J. A.; Mingarelli, C. M. F.; Lazio, T. J. W.; van Haasteren, R.

    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 (˜10-15 strain at f = 1 yr-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.

  14. Carbon nanofiber multiplexed array and Wireless Instantaneous Neurotransmitter Concentration Sensor for simultaneous detection of dissolved oxygen and dopamine

    PubMed Central

    Marsh, Michael P.; Koehne, Jessica E.; Andrews, Russell J.; Meyyappan, M.; Bennet, Kevin E.; Lee, Kendall H.

    2014-01-01

    Purpose While the mechanism of Deep Brain Stimulation (DBS) remains poorly understood, previous studies have shown that it evokes release of neurochemicals and induces activation of functional magnetic resonance imaging (fMRI) blood oxygen level-dependent signal in distinct areas of the brain. Therefore, the main purpose of this paper is to demonstrate the capabilities of the Wireless Instantaneous Neurotransmitter Concentration Sensor system (WINCS) in conjunction with a carbon nanofiber (CNF) multiplexed array electrode as a powerful tool for elucidating the mechanism of DBS through the simultaneous detection of multiple bioactive-molecules. Methods Patterned CNF nanoelectrode arrays were prepared on a 4-inch silicon wafer where each device consists of 3 × 3 electrode pads, 200 μm square, that contain CNFs spaced at 1μm intervals. The multiplexed carbon nanofiber CNF electrodes were integrated with WINCS to detect mixtures of dopamine (DA) and oxygen (O2) using fast scan cyclic voltammetry (FSCV) in vitro. Results First, simultaneous detection of O2 at two spatially different locations, 200 um apart, was demonstrated. Second, simultaneous detection of both O2 and DA at two spatially different locations, using two different decoupled waveforms was demonstrated. Third, controlled studies demonstrated that the waveform must be interleaved to avoid electrode crosstalk artifacts in the acquired data. Conclusions Multiplexed CNF nanoelectrode arrays for electrochemical detection of neurotransmitters show promise for the detection of multiple analytes with the application of time independent decoupled waveforms. Electrochemistry on CNF electrodes may be helpful in elucidating the mechanism of DBS, and may also provide the precision and sensitivity required for future applications in feedback modulated DBS neural control systems. PMID:24688800

  15. High-performance liquid chromatographic determination with photodiode array detection of ellagic acid in fresh and processed fruits.

    PubMed

    Amakura, Y; Okada, M; Tsuji, S; Tonogai, Y

    2000-10-27

    A high-performance liquid chromatographic (HPLC) procedure based on an isocratic elution with photodiode array detection has been developed for a simple and rapid determination of ellagic acid (EA) in fresh and processed fruits. The homogenized sample was refluxed with methanol and then the extract was refined using a solid-phase cartridge before HPLC. We analyzed EA in 40 kinds of fresh fruits and 11 kinds of processed fruits by the developed method. EA was found in several berries, fueijoa, pineapple and pomegranate. This is the first occurrence of the detection of EA in bayberry, fueijoa and pineapple.

  16. Portable e-Tongue based on Multi-channel LAPS Array with PVC Membrane for Rapid Environment Detection

    NASA Astrophysics Data System (ADS)

    Ha, D.; Yu, H.; Hu, N.; Wu, C. X.; Zhou, J.; Kirsanov, Dmitry; Legin, Andrey; Wang, P.

    2011-09-01

    A new kind of portable e-Tongue based on multi-channel LAPS array with PVC membrane has been designed for the rapid detection of environment situation, especially the seawater. It has the great advantages of depositing membranes which are offered by Chemistry Department, Saint-Petersburg State University on the sensors artificially with convenience and efficiency. To detect various heavy metal ions (Pb2+, Cd2+, Zn2+) simultaneously, respective Polyvinyl Chloride (PVC) membrane could be prepared on the surface of the silicon-based sensor in different channel.

  17. Investigation of a solvent-cast organogel to form a liquid-gel microinterface array for electrochemical detection of lysozyme.

    PubMed

    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. PMID:26398420

  18. Clinical Validation of Integrated Nucleic Acid and Protein Detection on an Electrochemical Biosensor Array for Urinary Tract Infection Diagnosis

    PubMed Central

    Mohan, Ruchika; Mach, Kathleen E.; Bercovici, Moran; Pan, Ying; Dhulipala, Lakshmi; Wong, Pak Kin; Liao, Joseph C.

    2011-01-01

    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 multiplexed detection

  19. Simultaneous isolation and detection of circulating tumor cells with a microfluidic silicon-nanowire-array integrated with magnetic upconversion nanoprobes.

    PubMed

    Wang, Chao; Ye, Min; Cheng, Liang; Li, Rui; Zhu, Wenwen; Shi, Zhen; Fan, Chunhai; He, Jinkang; Liu, Jian; Liu, Zhuang

    2015-06-01

    The development of sensitive and convenient methods for detection, enrichment, and analysis of circulating tumor cells (CTCs), which serve as an importance diagnostic indicator for metastatic progression of cancer, has received tremendous attention in recent years. In this work, a new approach characteristic of simultaneous CTC capture and detection is developed by integrating a microfluidic silicon nanowire (SiNW) array with multifunctional magnetic upconversion nanoparticles (MUNPs). The MUNPs were conjugated with anti-EpCAM antibody, thus capable to specifically recognize tumor cells in the blood samples and pull them down under an external magnetic field. The capture efficiency of CTCs was further improved by the integration with a microfluidic SiNW array. Due to the autofluorescence free nature in upconversion luminescence (UCL) imaging, our approach allows for highly sensitive detection of small numbers of tumor cells, which afterward could be collected for further analysis and re-culturing. We have further demonstrated that this approach can be applied to detect CTCs in clinical blood samples from lung cancer patients, and obtained consistent results by analyzing the UCL signals and the clinical outcomes of lung cancer metastasis. Therefore our approach represents a promising platform in CTC capture and detection with potential clinical utilization in cancer diagnosis and prognosis. PMID:25907039

  20. Real-time detection of DNA hybridization and melting on oligonucleotide arrays by using optical wave guides.

    PubMed

    Stimpson, D I; Hoijer, J V; Hsieh, W T; Jou, C; Gordon, J; Theriault, T; Gamble, R; Baldeschwieler, J D

    1995-07-01

    The challenge of the Human Genome Project is to increase the rate of DNA sequence acquisition by two orders of magnitude to complete sequencing of the human genome by the year 2000. The present work describes a rapid detection method using a two-dimensional optical wave guide that allows measurement of real-time binding or melting of a light-scattering label on a DNA array. A particulate label on the target DNA acts as a light-scattering source when illuminated by the evanescent wave of the wave guide and only the label bound to the surface generates a signal. Imaging/visual examination of the scattered light permits interrogation of the entire array simultaneously. Hybridization specificity is equivalent to that obtained with a conventional system using autoradiography. Wave guide melting curves are consistent with those obtained in the liquid phase and single-base discrimination is facile. Dilution experiments showed an apparent lower limit of detection at 0.4 nM oligonucleotide. This performance is comparable to the best currently known fluorescence-based systems. In addition, wave guide detection allows manipulation of hybridization stringency during detection and thereby reduces DNA chip complexity. It is anticipated that this methodology will provide a powerful tool for diagnostic applications that require rapid cost-effective detection of variations from known sequences.

  1. Quantum Dot and Polymer Composite Cross-Reactive Array for Chemical Vapor Detection.

    PubMed

    Bright, Collin J; Nallon, Eric C; Polcha, Michael P; Schnee, Vincent P

    2015-12-15

    A cross-reactive chemical sensing array was made from CdSe Quantum Dots (QDs) and five different organic polymers by inkjet printing to create segmented fluorescent composite regions on quartz substrates. The sensor array was challenged with exposures from two sets of analytes, including one set of 14 different functionalized benzenes and one set of 14 compounds related to security concerns, including the explosives trinitrotoluene (TNT) and ammonium nitrate. The array was broadly responsive to analytes with different chemical functionalities due to the multiple sensing mechanisms that altered the QDs' fluorescence. The sensor array displayed excellent discrimination between members within both sets. Classification accuracy of more than 93% was achieved, including the complete discrimination of very similar dinitrobenzene isomers and three halogenated, substituted benzene compounds. The simple fabrication, broad responsivity, and high discrimination capacity of this type of cross-reactive array are ideal qualities for the development of sensors with excellent sensitivity to chemical and explosive threats while maintaining low false alarm rates. PMID:26548712

  2. The Distributed Biological Observatory (DBO)-A Change Detection Array in the Pacific Arctic Sector

    NASA Astrophysics Data System (ADS)

    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.

  3. NDT process using Lamb waves generated/detected by ultrasonic phased array probes for the defect detection in metallic and composite plates

    NASA Astrophysics Data System (ADS)

    Leleux, A.; Micheau, P.; Castaings, M.

    2013-01-01

    One gel-coupled multi-element matrix ultrasonic probe is driven using the phased array principle, for launching/detecting pure Lamb modes in/from different directions along various types of plates, and taking into account the modes frequency and angular dispersive effects. It allows rapid inspection of large structures, from one remote fixed position of the probe. The set-up and principle of the process are presented, as well as its measured performances in terms of modal selectivity and directivity. Finally examples of defect detection are shown.

  4. Automated Flaw Detection Scheme For Cast Austenitic Stainless Steel Weld Specimens Using Hilbert Huang Transform Of Ultrasonic Phased Array Data

    SciTech Connect

    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.

  5. Microfluidic Biosensor Array with Integrated Poly(2,7-Carbazole)/Fullerene-Based Photodiodes for Rapid Multiplexed Detection of Pathogens

    PubMed Central

    Pires, Nuno Miguel Matos; Dong, Tao

    2013-01-01

    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 × 105 cells/mL for E. coli, 1 × 105 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. PMID:24287522

  6. Preparation of SiO2@ Au nanorod array as novel surface enhanced Raman substrate for trace pollutants detection

    NASA Astrophysics Data System (ADS)

    Hou, Meng-Jing; Zhang, Xian; Cui, Xiao-Yang; Liu, Can; Li, Zheng-Cao; Zhang, Zheng-Jun

    2015-03-01

    An effective surface enhanced Raman scattering (SERS) substrate is designed and fabricated by synthesis of SiO2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto SiO2 surface in order to create numerous “hot spots”. The detecting sensitivity of such substrate could be optimized by simply adjusting the deposition time of Au. Thus, it can be used for detection of Rhodamine 6G at concentration as low as 10-9 M. Furthermore, our SERS substrate is applied to detect 5 μg/g polychlorinated biphenyls in soil sample, which proves its potential for trace environmental pollutants detection. Project supported by the National Basic Research Program of China (Grant No. 2013CB934301), the National Natural Science Foundation of China (Grant No. 50931002), the Research Project of Chinese Ministry of Education (Grant No. 113007A), and the Initiative Scientific Research Program of Tsinghua University, China

  7. Rapid Determination of RNA Accessible Sites by Surface Plasmon Resonance Detection of Hybridization to DNA arrays

    PubMed Central

    Mandir, Joshua B.; Lockett, Matthew R.; Phillips, Margaret F.; Allawi, Hatim T.; Lyamichev, Victor I.; Smith, Lloyd M.

    2009-01-01

    RNA accessible sites are the regions in an RNA molecule, which are available for hybridization with complementary DNA or RNA molecules. The identification of these accessible sites is a critical first step in identifying antisense-mediated gene suppression sites, as well as in a variety of other RNA-based analysis methods. Here, we present a rapid, hybridization-based, label-free method of identifying RNA accessible sites with surface plasmon resonance imaging (SPRi) on in situ synthesized oligonucleotide arrays prepared on carbon-on-metal substrates. The accessible sites of three pre-miRNAs, miRNA precursors of ~75 nt in length, were determined by hybridizing the RNA molecules to RNA-specific tiling arrays. An array comprised of all possible 6mer oligonucleotide sequences was also utilized in this work, offering a universal platform capable of studying RNA molecules in a high throughput manner. PMID:19874056

  8. A 0.18-µm CMOS Array Sensor for Integrated Time-Resolved Fluorescence Detection

    PubMed Central

    Huang, Ta-chien D.; Sorgenfrei, Sebastian; Gong, Ping; Levicky, Rastislav; Shepard, Kenneth L.

    2010-01-01

    This paper describes the design of an active, integrated CMOS sensor array for fluorescence applications which enables time-gated, time-resolved fluorescence spectroscopy. The 64-by-64 array is sensitive to photon densities as low as 8.8 × 106 photons/cm2 with 64-point averaging and, through a differential pixel design, has a measured impulse response of better than 800 ps. Applications include both active microarrays and high-frame-rate imagers for fluorescence lifetime imaging microscopy. PMID:20436922

  9. Rational design of a minimal size sensor array for metal ion detection.

    PubMed

    Palacios, Manuel A; Wang, Zhuo; Montes, Victor A; Zyryanov, Grigory V; Anzenbacher, Pavel

    2008-08-01

    The focus of this study was to demonstrate that, in the luminescent sensors, the signal transduction may possibly be the most important part in the sensing process. Rational design of fluorescent sensor arrays for cations utilizing extended conjugated chromophores attached to 8-hydroxyquinoline is reported. All of the optical sensors utilized in the arrays comprise the same 8-hydroxyquinoline (8-HQ) receptor and various conjugated chromophores to yield a different response to various metal cations. This is because the conjugated chromophores attached to the receptor are partially quenched in their resting state, and upon the cation coordination by the 8-HQ, the resulting metalloquinolinolate complex displays a change in fluorescence. A delicate balance of conjugation, fluorescence enhancement, energy transfer, and a heavy metal quenching effect results in a fingerprint-like pattern of responses for each sensor-cation complex. Principal component analysis (PCA) and linear discriminant analysis (LDA) are used to demonstrate the contribution of individual sensors within the array, information that may be used to design sensor arrays with the smallest number of sensor elements. This approach allows discriminating between 10 cations by as few as two or even one sensor element. Examples of arrays comprising various numbers of sensor elements and their utility in qualitative identification of Ca(2+), Mg(2+), Cd(2+), Hg(2+), Co(2+), Zn(2+), Cu(2+), Ni(2+), Al(3+), and Ga(3+) ions are presented. A two-member array was found to identify 11 analytes with 100% accuracy. Also the best two of the sensors were tested alone and both were found to be able to discriminate among the samples with 99% and 96% accuracy, respectively. To illustrate the utility of this approach to a real-world application, identification of enhanced soft drinks based on their Ca(2+), Mg(2+), and Zn(2+) cation content was performed. The same approach to reducing array elements was used to construct three

  10. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    PubMed

    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. PMID:25970032

  11. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    PubMed

    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.

  12. Microfluidic chip-based nanoelectrode array as miniaturized biochemical sensing platform for prostate-specific antigen detection.

    PubMed

    Triroj, Napat; Jaroenapibal, Papot; Shi, Haibin; Yeh, Joanne I; Beresford, Roderic

    2011-02-15

    A microfluidic biosensor chip with an embedded three-electrode configuration is developed for the study of the voltammetric response of a nanoelectrode array with controlled inter-electrode distance in a nanoliter-scale sample volume. The on-chip three-electrode cell consists of a 5 × 5 array of Au working nanoelectrodes with radii between 60 and 120 nm, a Cl(2)-plasma-treated Ag/AgCl reference electrode, and a Au counter electrode. The nanoelectrode array is fabricated by creating high-aspect-ratio pores through an alumina insulating layer using an I(2) gas-assisted focused-ion-beam (FIB) milling, ion beam sculpting, and electrodeposition of Au. The glass substrate with the electrode pattern is assembled with a polydimethylsiloxane (PDMS) microchannel slab giving a volume of 180 nL for each channel. Cyclic voltammetry calibration with a standard redox species exhibits a significant increase of current density by two orders of magnitude compared to that obtained from a microelectrode. On-chip functionalization of the nanoelectrodes with a prostate-specific antigen (PSA) biosensor complex and detection of PSA based on a competitive immunoassay method are performed. The detection limit is approximately 10 pg/mL (∼270 fM), which corresponds to roughly 30,000 copies of PSA in the microchannel test volume.

  13. Rapid detection and identification of viral and bacterial fish pathogens using a DNA array-based multiplex assay.

    PubMed

    Lievens, B; Frans, I; Heusdens, C; Justé, A; Jonstrup, S P; Lieffrig, F; Willems, K A

    2011-11-01

    Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad-range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV-1, CyHV-2 and CyHV-3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study. PMID:21988358

  14. Rapid detection and identification of viral and bacterial fish pathogens using a DNA array-based multiplex assay.

    PubMed

    Lievens, B; Frans, I; Heusdens, C; Justé, A; Jonstrup, S P; Lieffrig, F; Willems, K A

    2011-11-01

    Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad-range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV-1, CyHV-2 and CyHV-3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study.

  15. Detection of Volatile Organic Compounds by Self-assembled Monolayer Coated Sensor Array with Concentration-independent Fingerprints

    NASA Astrophysics Data System (ADS)

    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.

  16. Detection of Volatile Organic Compounds by Self-assembled Monolayer Coated Sensor Array with Concentration-independent Fingerprints

    PubMed Central

    Chang, Ye; Tang, Ning; Qu, Hemi; Liu, Jing; Zhang, Daihua; Zhang, Hao; Pang, Wei; Duan, Xuexin

    2016-01-01

    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. PMID:27045012

  17. No Radio Flaring Detected from Cygnus X-3 at 3 GHz by Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    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.

  18. Gold nanoparticles-peptide based gas sensor arrays for the detection of food aromas.

    PubMed

    Compagnone, D; Fusella, G C; Del Carlo, M; Pittia, P; Martinelli, E; Tortora, L; Paolesse, R; Di Natale, C

    2013-04-15

    A gas sensor array based on peptide modified gold nanoparticles deposited onto 20MHz quartz crystal microbalances has been realized. Glutathione and its constituting aminoacids and dipeptides have been used as ligands. A great increase in sensitivity (2 orders of magnitude) was achieved using gold nanoparticles versus monolayer modified QCMs. The sensors have been characterised in terms of sensitivity for hexane, water, trimethylammine and ethanol. Highest sensitivity was found for water. The ability to discriminate typical food aromas as cis-3-hexenol, isopentylacetate, ethylacetate, and terpinen-4-ol dissolved in different solvents was studied using a gas sensor array constituted by gold nanoparticles modified with the glutathione peptides, thioglycolic acid and an heptapeptide. The array was found able to discriminate the food aromas, the response being dependent on the polarity of the solvent used. Tests on real olive oil samples gave a satisfactory separation among samples having defects versus non defected samples demonstrating that this approach has high potential for the development of gas sensor arrays to be used in real samples. PMID:23261699

  19. Establishment and application of a multiplex genetic mutation-detection method of lung cancer based on MassARRAY platform

    PubMed Central

    Tian, Hong-Xia; Zhang, Xu-Chao; Wang, Zhen; Chen, Jian-Guang; Chen, Shi-Liang; Guo, Wei-Bang; Wu, Yi-Long

    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 sequencing EGFR and KRAS 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, an FGFR2 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. PMID:27144063

  20. Detection properties of phase velocities with SPAC arrays including structural boundary

    NASA Astrophysics Data System (ADS)

    Shiraishi, H.; Asanuma, H.

    2013-12-01

    Microtremor survey method (MSM) is a technique to estimate subsurface velocity structures by inverting phase velocities of the surface waves in the microtremors. All the existing inversion techniques for the MSM have been deduced under an implicit assumption of horizontal velocity structure. Velocity structures in shallow sediment are, however, practically very inhomogeneous, and the assumption may not be suitable in many cases of the MSM applications. Therefore we have examined the behavior of estimated phase velocities with the SPAC technique when arrays intersect a structural boundary, because errors in velocity estimation in the MSM for inhomogeneous velocity cases have not been elucidated. An example of theoretical analysis is shown in Figs, where phase differences of two sensors which placed across a structural boundary have been analytically expressed and then the SPAC technique have been performed using complex coherence functions (Shiraishi et. al., 2006). Fig.1 shows the geometry of a SPAC array along with a velocity boundary. Here, we assumed different horizontal velocity model for right and left sides. Fig.2 shows estimated phase velocities for various locations of structural boundaries. This result shows that the estimated velocities gradually vary according to the location of boundaries and it seems that the phase velocities determined by the occupying rate of each structure along the length of the array. Therefore, in the case of the boundary placed inside the center of the array, the estimated velocities would be adopted intermediate value of the two different structures and the error is maximized. We have also examined these properties with three dimensional simulations and have confirmed similar features. Furthermore, we have examined some classifying measures of discontinuous structures within the array. We believe that these results will contribute to derive a new estimation technique for the MSM of covering discontinuous or gradient structures.

  1. Exome sequencing and arrayCGH detection of gene sequence and copy number variation between ILS and ISS mouse strains.

    PubMed

    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

  2. The use of waveform cross correlation at a three-component seismic array for detection, location, and magnitude estimation

    NASA Astrophysics Data System (ADS)

    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.

  3. Evaluation of the FilmArray® system for detection of Bacillus anthracis, Francisella tularensis, and Yersinia pestis

    SciTech Connect

    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.

  4. Incorporation of Slow Off-Rate Modified Aptamers Reagents in Single Molecule Array Assays for Cytokine Detection with Ultrahigh Sensitivity.

    PubMed

    Wu, Danlu; Katilius, Evaldas; Olivas, Edgar; Dumont Milutinovic, Milena; Walt, David R

    2016-09-01

    Slow off-rate modified aptamers (SOMAmers) are attractive protein recognition reagents due to their high binding affinities, stable chemical structures, easy production, and established selection process. Here, biotinylated SOMAmer reagents were incorporated into single molecule array (Simoa)-based assays in place of traditional detection antibodies for six cytokine targets. Optimization and validation were conducted for TNF-α as a demonstration using a capture antibody/detection-SOMAmer detection scheme to highlight the performance of this approach. The optimized assay has a broad dynamic range (>4 log10 units) and an ultralow detection limit of 0.67 fM (0.012 pg/mL). These results show comparable sensitivity to our antibody pair-based Simoa assays, and tens to thousands-fold enhancement in sensitivity compared with conventional ELISAs. High recovery percentages were observed in a spike-recovery test using human sera, demonstrating the feasibility of this novel Simoa assay in detecting TNF-α in clinically relevant samples. Detection SOMAmers were also used to detect other cytokines, such as IFN-γ, IL-1β, IL-2, IL-6, and IL-10, in human samples. Although not yet demonstrated, in principle it should be possible to eventually replace both the capture and detector antibodies with corresponding SOMAmer pairs in sandwich immunoassays. The combination of the ultrasensitive Simoa platform with the higher reliability of SOMAmer binding reagents will greatly benefit both biomarker discovery and disease diagnostic fields. PMID:27529794

  5. Photoelectrochemical properties and the detection mechanism of Bi2WO6 nanosheet modified TiO2 nanotube arrays.

    PubMed

    Pang, Yajun; Xu, Guangqing; Zhang, Xu; Lv, Jun; Shi, Kai; Zhai, Pengbo; Xue, Qianyun; Wang, Xuedong; Wu, Yucheng

    2015-10-28

    Bi2WO6 nanosheet modified TiO2 nanotube arrays were synthesized by an anodization method combined with sequential chemical bath deposition for enhancement of the photoelectrochemical detection performance. The structures, morphologies and elemental compositions of the nanotube arrays were characterized with X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectrometry. Bi2WO6 nanosheets were successfully deposited on the tube walls of TiO2 nanotubes. The photoelectrochemical property of Bi2WO6/TiO2 NTAs was determined with chronoamperometry and cyclic voltammetry using an electrochemical workstation equipped with a UV LED light (365 nm). The optimum detection sensitivity of glucose in water was determined to be 0.244 μA mM(-1) in the linear range from 0 to 2500 μM. Bi2WO6 modification on TiO2 NTAs simultaneously decreased the background photocurrent and increased the current response to organics, resulting in the enhancement of photoelectrochemical detection properties. Mechanisms of the Bi2WO6 modification are discussed by analyzing the photoelectrochemical processes, including optical absorption, charges transfer and surface electrochemical reactions. Direct oxidation by holes rather than indirect oxidation by ˙OH radicals is believed to be a key role in this enhancement.

  6. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection.

    PubMed

    Cui, Jiewu; Adeloju, Samuel B; Wu, Yucheng

    2014-01-27

    A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO(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(x) nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm(-2) mM(-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. PMID:24418144

  7. A coherent method for the detection and parameter estimation of continuous gravitational wave signals using a pulsar timing array

    SciTech Connect

    Wang, Yan; Mohanty, Soumya D.; Jenet, Fredrick A.

    2014-11-01

    The use of a high precision pulsar timing array is a promising approach to detecting gravitational waves in the very low frequency regime (10{sup –6}-10{sup –9} Hz) that is complementary to ground-based efforts (e.g., LIGO, Virgo) at high frequencies (∼10-10{sup 3} Hz) and space-based ones (e.g., LISA) at low frequencies (10{sup –4}-10{sup –1} Hz). One of the target sources for pulsar timing arrays is individual supermassive black hole binaries which are expected to form in galactic mergers. In this paper, a likelihood-based method for detection and parameter estimation is presented for a monochromatic continuous gravitational wave signal emitted by such a source. The so-called pulsar terms in the signal that arise due to the breakdown of the long-wavelength approximation are explicitly taken into account in this method. In addition, the method accounts for equality and inequality constraints involved in the semi-analytical maximization of the likelihood over a subset of the parameters. The remaining parameters are maximized over numerically using Particle Swarm Optimization. Thus, the method presented here solves the monochromatic continuous wave detection and parameter estimation problem without invoking some of the approximations that have been used in earlier studies.

  8. Sub-ppm detection of vapors using piezoresistive microcantilever array sensors

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Genki; Lang, Hans-Peter; Akiyama, Terunobu; Aeschimann, Laure; Staufer, Urs; Vettiger, Peter; Aono, Masakazu; Sakurai, Toshio; Gerber, Christoph

    2009-01-01

    The performance of microfabricated piezoresistive cantilever array sensors has been evaluated using various vapors of volatile organic compounds including alkanes with different chain length from 5 (n-pentane) to 14 (n-tetradecane). We demonstrate that piezoresistive microcantilever array sensors have the selectivity of discriminating individual alkanes in a homologous series as well as common volatile organic compounds according to principal component analysis. We developed a new method to evaluate the sensitivity, taking advantage of the low vapor pressures of alkanes with longer chains, such as n-dodecane, n-tridecane and n-tetradecane, under saturated vapor conditions. This method reveals sub-ppm sensitivity and the cantilever response is found to follow the mass of evaporated analytes as calculated using a quantitative model based on the Langmuir evaporation model.

  9. VERY LARGE ARRAY DETECTION OF THE 36 GHz ZEEMAN EFFECT IN DR21W REVISITED

    SciTech Connect

    Momjian, Emmanuel; Sjouwerman, Lorant O.; Fish, Vincent L.

    2012-09-20

    We report on the observation of the 36 GHz methanol maser line in the star-forming region DR21W to accurately measure the Zeeman effect. The Zeeman signature reported by Fish et al. became suspicious after an instrumental effect was discovered in the early days of the commissioning of the Very Large Array Wide-band Digital Architecture correlator. We conclude that the previously reported magnetic field strength of 58 mG (1.7 Hz mG{sup -1}/z) is instrumental in nature and thus incorrect. With the improved performance of the array, we now deduce a 3{sigma} limit of -4.7 to +0.4 mG (1.7 Hz mG{sup -1}/z) for the line-of-sight component of the magnetic field strength in DR21W.

  10. Carbon-on-metal films for surface plasmon resonance detection of DNA arrays.

    PubMed

    Lockett, Matthew R; Weibel, Stephen C; Phillips, Margaret F; Shortreed, Michael R; Sun, Bin; Corn, Robert M; Hamers, Robert J; Cerrina, Franco; Smith, Lloyd M

    2008-07-01

    Surface plasmon resonance (SPR) imaging affords label-free monitoring of biomolecule interactions in an array format. A surface plasmon conducting metal thin film is required for SPR measurements. Gold thin films are traditionally used in SPR experiments as they are readily functionalized with thiol-containing molecules through formation of a gold-sulfur bond. The lability of this gold-thiol linkage upon exposure to oxidizing conditions and ultraviolet light renders these surfaces incompatible with light-directed synthetic methods for fabricating DNA arrays. It is shown here that applying a thin carbon overlayer to the gold surface yields a chemically robust substrate that permits light-directed synthesis and also supports surface plasmons. DNA arrays fabricated on these carbon-metal substrates are used to analyze two classes of biomolecular interactions: DNA-DNA and DNA-protein. This new strategy allows the combinatorial study of binding interactions directly from native, unmodified biomolecules of interest and offers the possibility of discovering new ligands in complex mixtures such as cell lysates.

  11. Detection of the Odor Signature of Ovarian Cancer using DNA-Decorated Carbon Nanotube Field Effect Transistor Arrays

    NASA Astrophysics Data System (ADS)

    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.

  12. Development of a peptide nucleic acid array platform for the detection of genetically modified organisms in food.

    PubMed

    Germini, Andrea; Rossi, Stefano; Zanetti, Alessandro; Corradini, Roberto; Fogher, Corrado; Marchelli, Rosangela

    2005-05-18

    Two previously developed platforms, a multiplex polymerase chain reaction (PCR) and a peptide nucleic acid (PNA) array, the former allowing for the simultaneous detection of five transgenes and two endogenous controls in food and feed matrices and the latter for the assessment of the identity of amplified PCR products, were combined in order to develop a PNA array device for the screening of genetically modified organisms (GMOs) in food. PNA probes were opportunely designed, synthesized, and deposited on commercial slides. The length of the probes as well as the distance of the probes from the surface were evaluated and found to be critical points. The most suitable probes were found to be 15-mer PNAs linked to the slide surface by means of two 2-(2-aminoethoxy)ethoxyacetic acids as spacers. The device was tested on a model system constituted by flour samples containing a mixture of standards at known concentrations of transgenic material, in particular Roundup Ready soybean and Bt11, Bt176, Mon810, and GA21 maize: The DNA was amplified using the specific multiplex PCR method and tested on the PNA array. The method proposed was found to be able to correctly identify every GMO present in the tested samples.

  13. Analysis and experimental verification of DNA single-base polymerization detection using CMOS FET-based redox potential sensor array

    NASA Astrophysics Data System (ADS)

    Ishihara, Hiroki; Niitsu, Kiichi; Nakazato, Kazuo

    2015-04-01

    We report a method for detecting DNA single-base polymerization using a complementary metal oxide semiconductor (CMOS) field effect transistor (FET)-based redox potential sensor array. The redox potential detection method has the possibility of high-accuracy detection of DNA polymerization compared with other FET-based methods because this method is not affected by buffer conditions. First, we demonstrated pyrophosphate (PPi) detection assuming that DNA polymerization occurred. This result showed a sensitivity of -12.3 mV/decade for a logarithmic concentration of PPi in the range of 0.05-1 mM. To investigate the appropriateness of this measurement result, we conducted a theoretical analysis using the equilibrium constant. Next, we demonstrated DNA single-base polymerization detection. There was a 5.65 mV difference between the reaction solutions with a mismatched deoxynucleotide triphosphate (dNTP) and with a matched dNTP. This voltage difference is reasonable given the PPi detection result, which achieves a sufficient signal-to-noise ratio (SNR) of more than 20 dB.

  14. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    NASA Astrophysics Data System (ADS)

    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.

  15. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    SciTech Connect

    López Terrones, Marcos Alonso; Solís-Nájera, Sergio Enrique

    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.

  16. Tripling the detection view of high-frequency linear-array-based photoacoustic computed tomography by using two planar acoustic reflectors

    PubMed Central

    Li, Guo; Xia, Jun; Wang, Kun; Maslov, Konstantin; Anastasio, Mark A.

    2015-01-01

    Background Linear-array-based photoacoustic computed tomography (PACT) suffers from a limited view. Circular scanning does increase the detection view angle but is time-consuming. Therefore, it is desirable to increase the detection view angle of linear-array-based PACT without sacrificing imaging speed. Methods Two planar acoustic reflectors placed at 120 degrees to each other were added to a linear-array-based PACT system. Each reflector redirects originally undetectable photoacoustic waves back to the transducer array elements, and together they triple the original detection view angle of the PACT system. Results Adding two reflectors increased the detection view angle from 80 to 240 degrees. As a comparison, a single-reflector PACT has a detection view angle of only 160 degrees. A leaf skeleton phantom with a rich vascular network was imaged with the double-reflector PACT, and most of its features were recovered. Conclusions The two acoustic reflectors triple the detection view angle of a linear-array-based PACT without compromising the original imaging speed. This nearly full-view detection capability produces higher-quality images than single-reflector PACT or conventional PACT without reflectors. PMID:25694954

  17. Accuracy requirements of optical linear algebra processors in adaptive optics imaging systems

    NASA Technical Reports Server (NTRS)

    Downie, John D.

    1990-01-01

    A ground-based adaptive optics imaging telescope system attempts to improve image quality by detecting and correcting for atmospherically induced wavefront aberrations. The required control computations during each cycle will take a finite amount of time. Longer time delays result in larger values of residual wavefront error variance since the atmosphere continues to change during that time. Thus an optical processor may be well-suited for this task. This paper presents a study of the accuracy requirements in a general optical processor that will make it competitive with, or superior to, a conventional digital computer for the adaptive optics application. An optimization of the adaptive optics correction algorithm with respect to an optical processor's degree of accuracy is also briefly discussed.

  18. Modeling and Detection of Regional Depth Phases at the GERESS Array

    NASA Astrophysics Data System (ADS)

    Apoloner, Maria-Theresia; Bokelmann, Götz

    2015-04-01

    The Vienna Basin in Eastern Austria is a region of low to moderate seismicity, and hence the seismological network coverage
 is relatively sparse. Nevertheless, the area is one of the most densely populated and most developed areas in Austria. The largest instrumentally recorded magnitude is around 5, and the Vienna 
Basin fault system (VBFS), which branches beneath the Basin, occasionally shows earthquakes with magnitudes larger than 4. So accurate earthquake location, including depth estimation and relation to faults is not only important for understanding tectonic processes, but also for estimating seismic hazard. Particularly depth estimation needs a dense seismic network around the suspected epicenter. If the station coverage is not sufficient, the depth can only be estimated roughly. Regional Depth Phases (RDP) like sPg, sPmP and sPn have already been used successfully for calculating depth even if only observable from one station. However, especially in regions with sedimentary basins these phases prove difficult or impossible to recover from the seismic records. For this study we use seismic array data from GERESS, an array which has been operating for more than 20 years. It is located 220 km to the Northwest of the Vienna Basin, which - according to literature - is a suitable distance to recover PmP and sPmP phases. We use array processing on recent earthquake data from the Vienna Basin with local magnitudes > 4 to reduce the SNR and to search for RDP. The same processing is performed on synthetic data specifically modeled for this application. We compare real and synthetic results to assert which phases can be identified and to what extent depth estimation can be improved.

  19. Light-addressable measurements of cellular oxygen consumption rates in microwell arrays based on phase-based phosphorescence lifetime detection

    PubMed Central

    Huang, Shih-Hao; Hsu, Yu-Hsuan; Wu, Chih-Wei; Wu, Chang-Jer

    2012-01-01

    A digital light modulation system that utilizes a modified commercial digital micromirror device (DMD) projector, which is equipped with a UV light-emitting diode as a light modulation source, has been developed to spatially direct excited light toward a microwell array device to detect the oxygen consumption rate (OCR) of single cells via phase-based phosphorescence lifetime detection. The microwell array device is composed of a combination of two components: an array of glass microwells containing Pt(II) octaethylporphine (PtOEP) as the oxygen-sensitive luminescent layer and a microfluidic module with pneumatically actuated glass lids set above the microwells to controllably seal the microwells of interest. By controlling the illumination pattern on the DMD, the modulated excitation light can be spatially projected to only excite the sealed microwell for cellular OCR measurements. The OCR of baby hamster kidney-21 fibroblast cells cultivated on the PtOEP layer within a sealed microwell has been successfully measured at 104 ± 2.96 amol s−1 cell−1. Repeatable and consistent measurements indicate that the oxygen measurements did not adversely affect the physiological state of the measured cells. The OCR of the cells exhibited a good linear relationship with the diameter of the microwells, ranging from 400 to 1000 μm and containing approximately 480 to 1200 cells within a microwell. In addition, the OCR variation of single cells in situ infected by Dengue virus with a different multiplicity of infection was also successfully measured in real-time. This proposed platform provides the potential for a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery. PMID:24348889

  20. DNA arrays, electronic noses and tongues, biosensors and receptors for rapid detection of toxigenic fungi and mycotoxins: a review.

    PubMed

    Logrieco, A; Arrigan, D W M; Brengel-Pesce, K; Siciliano, P; Tothill, I

    2005-04-01

    This paper presents an overview of how microsystem technology tools can be applied to the development of rapid, out-of-laboratory measurement capabilities for the determinations of toxigenic fungi and mycotoxins in foodstuffs. Most of the topics discussed are all under investigation within the European Commission-sponsored project Good-Food (FP6-IST). These are DNA arrays, electronic noses and electronic tongues for the detection of fungal contaminants in feed, and biosensors and chemical sensors based on microfabricated electrode systems, antibodies and novel synthetic receptors for the detection of specific mycotoxins. The approach to resolution of these difficult measurement problems in real matrices requires a multidisciplinary approach. The technology tools discussed can provide a route to the rapid, on-site generation of data that can aid the safe production of high-quality foodstuffs.

  1. Gun muzzle flash detection using a single photon avalanche diode array in 0.18µm CMOS technology

    NASA Astrophysics Data System (ADS)

    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.

  2. Design of a portable noninvasive photoacoustic glucose monitoring system integrated laser diode excitation with annular array detection

    NASA Astrophysics Data System (ADS)

    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.

  3. First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

    SciTech Connect

    Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen; Güdel, Manuel; Rupen, Michael

    2014-06-20

    We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

  4. A library-screening approach for developing a fluorescence sensing array for the detection of metal ions.

    PubMed

    Smith, David G; Sajid, Naveed; Rehn, Simone; Chandramohan, Ramya; Carney, Isaac J; Khan, Misbahul A; New, Elizabeth J

    2016-08-01

    Detection of individual metal ions is of importance across a range of fields of chemistry including environmental monitoring, and health and disease. Fluorescence is a highly sensitive technique and small fluorescent molecules are widely used for the detection and quantification of metal ions in various applications. Achieving specificity for a single metal from a single sensor is always a challenge. An alternative to selective sensing is the use of a number of non-specific sensors, in an array, which together respond in a unique pattern to each analyte. Here we show that screening a library of compounds can give a small sensor set that can be used to identify a range of metal ions following PCA and LDA. We explore a method for screening the initial compounds to identify the best performing sensors. We then present our method for reducing the size of the sensor array, resulting in a four-membered system, which is capable of identifying nine distinct metal ion species in lake water. PMID:27291513

  5. Label-free electrical detection of cardiac biomarker with complementary metal-oxide semiconductor-compatible silicon nanowire sensor arrays.

    PubMed

    Chua, Jay Huiyi; Chee, Ru-Ern; Agarwal, Ajay; Wong, She Mein; Zhang, Guo-Jun

    2009-08-01

    Arrays of highly ordered silicon nanowire (SiNW) clusters are fabricated using complementary metal-oxide semiconductor (CMOS) field effect transistor-compatible technology, and the ultrasensitive, label-free, electrical detection of cardiac biomarker in real time using the array sensor is presented. The successful detection of human cardiac troponin-T (cTnT) has been demonstrated in an assay buffer solution of concentration down to 1 fg/mL, as well as in an undiluted human serum environment of concentration as low as 30 fg/mL. The high specificity, selectivity, and swift response time of the SiNWs to the presence of ultralow concentrations of a target protein in a biological analyte solution, even in the presence of a high total protein concentration, paves the way for the development of a medical diagnostic system for point-of-care application that is able to provide an early and accurate indication of cardiac cellular necrosis. PMID:20337397

  6. Structural Characterization of Plasma Metabolites Detected via LC-Electrochemical Coulometric Array using LC-UV Fractionation, MS, and NMR

    PubMed Central

    Bird, Susan S.; Sheldon, Diane P.; Gathungu, Rose M.; Vouros, Paul; Kautz, Roger; Matson, Wayne R.; Kristal, Bruce S.

    2012-01-01

    Liquid chromatography (LC) separation combined with electrochemical coulometric array detection (EC), is a sensitive, reproducible, and robust technique that can detect hundreds of redox-active metabolites down to the level of femtograms on column, making it ideal for metabolomics profiling. EC detection cannot, however, structurally characterize unknown metabolites that comprise these profiles. Several aspects of LC-EC methods prevent a direct transfer to other structurally-informative analytical methods, such as LC-MS and NMR. These include system limits of detection, buffer requirements, and detection mechanisms. To address these limitations, we developed a workflow based on the concentration of plasma, metabolite extraction, and offline LC-UV fractionation. Pooled human plasma was used to provide sufficient material necessary for multiple sample concentrations and platform analyses. Offline parallel LC-EC and LC-MS methods were established that correlated standard metabolites between the LC-EC profiling method and the mass spectrometer. Peak retention times (RT) from the LC-MS and LC-EC system were linearly related (r2=0.99); thus LC-MS RTs could be directly predicted from the LC-EC signals. Subsequent offline microcoil-NMR analysis of these collected fractions was used to confirm LC-MS characterizations by providing complementary, structural data. This work provides a validated workflow that is transferrable across multiple platforms and provides the unambiguous structural identifications necessary to move primary mathematically-driven LC-EC biomarker discovery into biological and clinical utility. PMID:23106399

  7. Femtomolar Detection of Silver Nanoparticles by Flow-Enhanced Direct-Impact Voltammetry at a Microelectrode Array

    PubMed Central

    2016-01-01

    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, B2014, 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. Langmuir2014, 30, 13462]. PMID:27494652

  8. Femtomolar Detection of Silver Nanoparticles by Flow-Enhanced Direct-Impact Voltammetry at a Microelectrode Array.

    PubMed

    Sokolov, Stanislav V; Bartlett, Thomas R; Fair, Peter; Fletcher, Stephen; Compton, Richard G

    2016-09-01

    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]. PMID:27494652

  9. Multiple coupling in plasmonic metal/dielectric hollow nanocavity arrays for highly sensitive detection

    NASA Astrophysics Data System (ADS)

    Yin, Jun; Zang, Yashu; Yue, Chuang; He, Xu; Yang, Hongtao; Wu, De-Yin; Wu, Min; Kang, Junyong; Wu, Zhihao; Li, Jing

    2015-08-01

    Recently, the plasmonic coupled optical cavity has gained much attention due to its attractive properties in light manipulation, e.g. high Q optical resonance, local field enhancements and extraordinary transmission. The strongly enhanced local field originated from the plasmonic resonance hybridizing with the optical cavity mode presents great potential for application to chemical and biological sensing. Here, the multiple coupling effect between plasmonic mode and optical cavity mode has been demonstrated in self-assembled metal/dielectric hollow-nanosphere (HNS) arrays and the strongly enhanced local field originated from the inter-coupling of the plasmonic cavities was further employed for highly sensitive recyclable SERS sensing.Recently, the plasmonic coupled optical cavity has gained much attention due to its attractive properties in light manipulation, e.g. high Q optical resonance, local field enhancements and extraordinary transmission. The strongly enhanced local field originated from the plasmonic resonance hybridizing with the optical cavity mode presents great potential for application to chemical and biological sensing. Here, the multiple coupling effect between plasmonic mode and optical cavity mode has been demonstrated in self-assembled metal/dielectric hollow-nanosphere (HNS) arrays and the strongly enhanced local field originated from the inter-coupling of the plasmonic cavities was further employed for highly sensitive recyclable SERS sensing. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03193a

  10. Detection of multiple autoantibodies in patients with ankylosing spondylitis using nucleic acid programmable protein arrays.

    PubMed

    Wright, Cynthia; Sibani, Sahar; Trudgian, David; Fischer, Roman; Kessler, Benedikt; LaBaer, Joshua; Bowness, Paul

    2012-02-01

    Ankylosing spondylitis (AS) is a common, inflammatory rheumatic disease that primarily affects the axial skeleton and is associated with sacroiliitis, uveitis, and enthesitis. Unlike other autoimmune rheumatic diseases, such as rheumatoid arthritis or systemic lupus erythematosus, autoantibodies have not yet been reported to be a feature of AS. We therefore wished to determine whether plasma from patients with AS contained autoantibodies and, if so, characterize and quantify this response in comparison to patients with rheumatoid arthritis (RA) and healthy controls. Two high density nucleic acid programmable protein arrays expressing a total of 3498 proteins were screened with plasma from 25 patients with AS, 17 with RA, and 25 healthy controls. Autoantigens identified were subjected to Ingenuity Pathway Analysis to determine the patterns of signaling cascades or tissue origin. 44% of patients with ankylosing spondylitis demonstrated a broad autoantibody response, as compared with 33% of patients with RA and only 8% of healthy controls. Individuals with AS demonstrated autoantibody responses to shared autoantigens, and 60% of autoantigens identified in the AS cohort were restricted to that group. The autoantibody responses in the AS patients were targeted toward connective, skeletal, and muscular tissue, unlike those of RA patients or healthy controls. Thus, patients with AS show evidence of systemic humoral autoimmunity and multispecific autoantibody production. Nucleic acid programmable protein arrays constitute a powerful tool to study autoimmune diseases.

  11. Modeling and detection of regional depth phases at the GERES array

    NASA Astrophysics Data System (ADS)

    Apoloner, M.-T.; Bokelmann, G.

    2015-08-01

    The Vienna Basin in Eastern Austria is a region of low to moderate seismicity, and hence the seismological network coverage is relatively sparse. Nevertheless, the area is one of the most densely populated and most developed areas in Austria, so accurate earthquake location, including depth estimation and relation to faults is not only important for understanding tectonic processes, but also for estimating seismic hazard. Particularly depth estimation needs a dense seismic network around the anticipated epicenter. If the station coverage is not sufficient, the depth can only be estimated roughly. Regional Depth Phases (RDP) like sPg, sPmP and sPn have been already used successfully for calculating depth even if only observable from one station. However, especially in regions with sedimentary basins these phases prove difficult or impossible to recover from the seismic records. For this study we use seismic array data from GERES. It is 220 km to the North West of the Vienna Basin, which - according to literature - is a suitable distance to recover PmP and sPmP phases. We use array processing on recent earthquake data from the Vienna Basin with local magnitudes from 2.1 to 4.2 to reduce the SNR and to search for RDP. At the same time, we do similar processing on synthetic data specially modeled for this application. We compare real and synthetic results to assess which phases can be identified and to what extent depth estimation can be improved. Additionally, we calculate a map of lateral propagation behavior of RDP for a typical strike-slip earthquake in our region of interest up to 400 km distance. For our study case RDP propagation is strongly azimuthally dependent. Also, distance ranges differ from literature sources. Comparing with synthetic seismograms we identify PmP and PbP phases with array processing as strongest arrivals. Although the associated depth phases cannot be identified at this distance and azimuth, identification of the PbP phases limits possible

  12. The Trace Analysis of DEET in Water using an On-line Preconcentration Column and Liquid Chromatography with UV Photodiode Array Detection

    EPA Science Inventory

    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...

  13. Impedance biosensor for the rapid detection of Listeria spp. based on aptamer functionalized Pt-interdigitated microelectrodes array

    NASA Astrophysics Data System (ADS)

    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.

  14. Analytical high-speed countercurrent chromatography with photodiode array detection (HSCCC-UV)

    SciTech Connect

    Schaufelberger, D.E. )

    1989-01-01

    The use of analytical high-speed countercurrent chromatography with a photodiode array detector (HSCCC-UV) is described. Reduction of detector noise caused by non-retained stationary phase was achieved by adding an auxiliary solvent (MeOH, isoPrOH) by means of a post-column reactor. The technique was applied to the separation of aromatic compounds and natural products in Hexane-MeOH-H{sub 2} and CHCl{sub 3}-MeOH-H{sub 2}O solvent systems. On-line recorded UV spectra were almost identical to those obtained with pure standards in methanol. Spectra obtained by HSCCC-UV can be used to characterize separated compounds and facilitate peak identification.

  15. A Microcantilever Sensor Array for the Detection and Inventory of Desert Tortoises

    SciTech Connect

    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.

  16. High-resolution optical coherence tomography using self-adaptive FFT and array detection

    NASA Astrophysics Data System (ADS)

    Zhao, Yonghua; Chen, Zhongping; Xiang, Shaohua; Ding, Zhihua; Ren, Hongwu; Nelson, J. Stuart; Ranka, Jinendra K.; Windeler, Robert S.; Stentz, Andrew J.

    2001-05-01

    We developed a novel optical coherence tomographic (OCT) system which utilized broadband continuum generation for high axial resolution and a high numeric-aperture (N.A.) Objective for high lateral resolution (<5 micrometers ). The optimal focusing point was dynamically compensated during axial scanning so that it can be kept at the same position as the point that has an equal optical path length as that in the reference arm. This gives us uniform focusing size (<5 mum) at different depths. A new self-adaptive fast Fourier transform (FFT) algorithm was developed to digitally demodulate the interference fringes. The system employed a four-channel detector array for speckle reduction that significantly improved the image's signal-to-noise ratio.

  17. Detection and classification of related lipopolysaccharides via a small array of immobilized antimicrobial peptides.

    PubMed

    Uzarski, Joshua R; Mello, Charlene M

    2012-09-01

    A small array of antimicrobial peptides comprising three cysteine-terminated natural sequences covalently immobilized to pendant surface maleimide groups are used to bind and successfully discriminate five types of lipopolysaccharide (LPS) molecules. Using surface plasmon resonance, LPSs isolated from four strains of Escherichia coli and one strain of Pseudomonas aeruginosa yield distinct binding profiles to the three immobilized peptides. Linear discriminant analysis generated 100% training set and 80% validation set classification success for the 40 samples evaluated. This work demonstrates the discriminatory binding capabilities of immobilized antimicrobial peptides toward LPS molecules and alludes to their use as probes in pathogen sensing devices potentially superior to the current state-of-the-art. PMID:22881053

  18. A 256-TES Array for the Detection of CMB B-Mode Polarisation

    NASA Astrophysics Data System (ADS)

    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.

  19. Synthesis of Fe Doped ZnO Nanowire Arrays that Detect Formaldehyde Gas.

    PubMed

    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.

  20. Synthesis of Fe Doped ZnO Nanowire Arrays that Detect Formaldehyde Gas.

    PubMed

    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. PMID:27483827

  1. High-resolution parallel-detection sensor array using piezo-phototronics effect

    SciTech Connect

    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.

  2. CRISPR Spacer Arrays for Detection of Viral Signatures from Acidic Hot Springs

    NASA Astrophysics Data System (ADS)

    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.

  3. A Versatile Multiple Target Detection System Based on DNA Nano-assembled Linear FRET Arrays

    PubMed Central

    Li, Yansheng; Du, Hongwu; Wang, Wenqian; Zhang, Peixun; Xu, Liping; Wen, Yongqiang; Zhang, Xueji

    2016-01-01

    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. PMID:27230484

  4. A Versatile Multiple Target Detection System Based on DNA Nano-assembled Linear FRET Arrays.

    PubMed

    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.

  5. A Versatile Multiple Target Detection System Based on DNA Nano-assembled Linear FRET Arrays

    NASA Astrophysics Data System (ADS)

    Li, Yansheng; Du, Hongwu; Wang, Wenqian; Zhang, Peixun; Xu, Liping; Wen, Yongqiang; Zhang, Xueji

    2016-05-01

    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.

  6. Single molecule detection using charge-coupled device array technology. Technical progress report

    SciTech Connect

    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.

  7. Spectrum of enteropathogens detected by the FilmArray GI Panel in a multicentre study of community-acquired gastroenteritis.

    PubMed

    Spina, A; Kerr, K G; Cormican, M; Barbut, F; Eigentler, A; Zerva, L; Tassios, P; Popescu, G A; Rafila, A; Eerola, E; Batista, J; Maass, M; Aschbacher, R; Olsen, K E P; Allerberger, F

    2015-08-01

    The European, multicentre, quarterly point-prevalence study of community-acquired diarrhoea (EUCODI) analysed stool samples received at ten participating clinical microbiology laboratories (Austria, Finland, France, Germany, Greece, Ireland, Italy, Portugal, Romania, and the UK) in 2014. On four specified days, each local laboratory submitted samples from ≤20 consecutive patients to the Austrian Study Centre for further testing with the FilmArray GI Panel (BioFire Diagnostics, Salt Lake City, UT, USA). Of the 709 samples from as many patients received, 325 (45.8%) tested negative, 268 (37.8%) yielded only one organism, and 116 (16.4%) yielded multiple organisms. Positivity rates ranged from 41% (30 of 73 samples) in France to 74% (59 of 80 samples) in Romania. With the exception of Entamoeba histolytica and Vibrio cholerae, all of the 22 targeted pathogens were detected at least once. Enteropathogenic Escherichia coli, Campylobacter species, toxigenic Clostridium difficile, enteroaggregative E. coli, norovirus and enterotoxigenic E. coli were the six most commonly detected pathogens. When tested according to local protocols, seven of 128 positive samples (5.5%) yielded multiple organisms. Overall, the FilmArray GI Panel detected at least one organism in 54.2% (384/709) of the samples, as compared with 18.1% (128/709) when testing was performed with conventional techniques locally. This underlines the considerable potential of multiplex PCR to improve routine stool diagnostics in community-acquired diarrhoea. Classic culture methods directed at the isolation of specific pathogens are increasingly becoming second-line tools, being deployed when rapid molecular tests give positive results. This optimizes the yield from stool examinations and dramatically improves the timeliness of diagnosis. PMID:25908431

  8. Spectrum of enteropathogens detected by the FilmArray GI Panel in a multicentre study of community-acquired gastroenteritis.

    PubMed

    Spina, A; Kerr, K G; Cormican, M; Barbut, F; Eigentler, A; Zerva, L; Tassios, P; Popescu, G A; Rafila, A; Eerola, E; Batista, J; Maass, M; Aschbacher, R; Olsen, K E P; Allerberger, F

    2015-08-01

    The European, multicentre, quarterly point-prevalence study of community-acquired diarrhoea (EUCODI) analysed stool samples received at ten participating clinical microbiology laboratories (Austria, Finland, France, Germany, Greece, Ireland, Italy, Portugal, Romania, and the UK) in 2014. On four specified days, each local laboratory submitted samples from ≤20 consecutive patients to the Austrian Study Centre for further testing with the FilmArray GI Panel (BioFire Diagnostics, Salt Lake City, UT, USA). Of the 709 samples from as many patients received, 325 (45.8%) tested negative, 268 (37.8%) yielded only one organism, and 116 (16.4%) yielded multiple organisms. Positivity rates ranged from 41% (30 of 73 samples) in France to 74% (59 of 80 samples) in Romania. With the exception of Entamoeba histolytica and Vibrio cholerae, all of the 22 targeted pathogens were detected at least once. Enteropathogenic Escherichia coli, Campylobacter species, toxigenic Clostridium difficile, enteroaggregative E. coli, norovirus and enterotoxigenic E. coli were the six most commonly detected pathogens. When tested according to local protocols, seven of 128 positive samples (5.5%) yielded multiple organisms. Overall, the FilmArray GI Panel detected at least one organism in 54.2% (384/709) of the samples, as compared with 18.1% (128/709) when testing was performed with conventional techniques locally. This underlines the considerable potential of multiplex PCR to improve routine stool diagnostics in community-acquired diarrhoea. Classic culture methods directed at the isolation of specific pathogens are increasingly becoming second-line tools, being deployed when rapid molecular tests give positive results. This optimizes the yield from stool examinations and dramatically improves the timeliness of diagnosis.

  9. Labeled RFS-Based Track-Before-Detect for Multiple Maneuvering Targets in the Infrared Focal Plane Array

    PubMed Central

    Li, Miao; Li, Jun; Zhou, Yiyu

    2015-01-01

    The problem of jointly detecting and tracking multiple targets from the raw observations of an infrared focal plane array is a challenging task, especially for the case with uncertain target dynamics. In this paper a multi-model labeled multi-Bernoulli (MM-LMB) track-before-detect method is proposed within the labeled random finite sets (RFS) framework. The proposed track-before-detect method consists of two parts—MM-LMB filter and MM-LMB smoother. For the MM-LMB filter, original LMB filter is applied to track-before-detect based on target and measurement models, and is integrated with the interacting multiple models (IMM) approach to accommodate the uncertainty of target dynamics. For the MM-LMB smoother, taking advantage of the track labels and posterior model transition probability, the single-model single-target smoother is extended to a multi-model multi-target smoother. A Sequential Monte Carlo approach is also presented to implement the proposed method. Simulation results show the proposed method can effectively achieve tracking continuity for multiple maneuvering targets. In addition, compared with the forward filtering alone, our method is more robust due to its combination of forward filtering and backward smoothing. PMID:26670234

  10. Labeled RFS-Based Track-Before-Detect for Multiple Maneuvering Targets in the Infrared Focal Plane Array.

    PubMed

    Li, Miao; Li, Jun; Zhou, Yiyu

    2015-01-01

    The problem of jointly detecting and tracking multiple targets from the raw observations of an infrared focal plane array is a challenging task, especially for the case with uncertain target dynamics. In this paper a multi-model labeled multi-Bernoulli (MM-LMB) track-before-detect method is proposed within the labeled random finite sets (RFS) framework. The proposed track-before-detect method consists of two parts-MM-LMB filter and MM-LMB smoother. For the MM-LMB filter, original LMB filter is applied to track-before-detect based on target and measurement models, and is integrated with the interacting multiple models (IMM) approach to accommodate the uncertainty of target dynamics. For the MM-LMB smoother, taking advantage of the track labels and posterior model transition probability, the single-model single-target smoother is extended to a multi-model multi-target smoother. A Sequential Monte Carlo approach is also presented to implement the proposed method. Simulation results show the proposed method can effectively achieve tracking continuity for multiple maneuvering targets. In addition, compared with the forward filtering alone, our method is more robust due to its combination of forward filtering and backward smoothing. PMID:26670234

  11. Labeled RFS-Based Track-Before-Detect for Multiple Maneuvering Targets in the Infrared Focal Plane Array.

    PubMed

    Li, Miao; Li, Jun; Zhou, Yiyu

    2015-12-08

    The problem of jointly detecting and tracking multiple targets from the raw observations of an infrared focal plane array is a challenging task, especially for the case with uncertain target dynamics. In this paper a multi-model labeled multi-Bernoulli (MM-LMB) track-before-detect method is proposed within the labeled random finite sets (RFS) framework. The proposed track-before-detect method consists of two parts-MM-LMB filter and MM-LMB smoother. For the MM-LMB filter, original LMB filter is applied to track-before-detect based on target and measurement models, and is integrated with the interacting multiple models (IMM) approach to accommodate the uncertainty of target dynamics. For the MM-LMB smoother, taking advantage of the track labels and posterior model transition probability, the single-model single-target smoother is extended to a multi-model multi-target smoother. A Sequential Monte Carlo approach is also presented to implement the proposed method. Simulation results show the proposed method can effectively achieve tracking continuity for multiple maneuvering targets. In addition, compared with the forward filtering alone, our method is more robust due to its combination of forward filtering and backward smoothing.

  12. Crosstalk between adjacent nanopores in a solid-state membrane array for multi-analyte high-throughput biomolecule detection

    NASA Astrophysics Data System (ADS)

    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.

  13. Mini-Array of Multiple Tumor-Associated Antigens to Enhance Autoantibody Detection for Immunodiagnosis of Hepatocellular Carcinoma

    PubMed Central

    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

  14. Tailored surface-enhanced Raman nanopillar arrays fabricated by laser-assisted replication for biomolecular detection using organic semiconductor lasers.

    PubMed

    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.

  15. Research on detection method of end gap of piston rings based on area array CCD and image processing

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Wang, Zhong; Liu, Qi; Li, Lin

    2012-01-01

    Piston ring is one of the most important parts in internal combustion engine, and the width of end gap is an important parameter which should be detected one by one. In comparison to the previous measurements of end gap, a new efficient detection method is presented based on computer vision and image processing theory. This paper describes the framework and measuring principle of the measurement system. In which, the image processing algorithm is highlighted. Firstly, the partial end gap image of piston ring is acquired by the area array CCD; secondly, the end gap edge contour which is connected by single pixel is obtained by grayscale threshold segmentation, mathematical morphology contour edge detection, contour trace and other image processing tools; finally, the distance between the two end gap edge contour lines is calculated by using the least distance method of straight-line fitting. It has been proved by the repetitive experiments that the measurement accuracy can reach 0.01mm. What's more, the detection efficiency of automatic inspected instrument on parameters of piston ring based on this method can reach 10~12 pieces/min.

  16. Automated Detection of Toxigenic Clostridium difficile in Clinical Samples: Isothermal tcdB Amplification Coupled to Array-Based Detection

    PubMed Central

    Pasko, Chris; Groves, Benjamin; Ager, Edward; Corpuz, Maylene; Frech, Georges; Munns, Denton; Smith, Wendy; Warcup, Ashley; Denys, Gerald; Ledeboer, Nathan A.; Lindsey, Wes; Owen, Charles; Rea, Larry; Jenison, Robert

    2012-01-01

    Clostridium difficile can carry a genetically variable pathogenicity locus (PaLoc), which encodes clostridial toxins A and B. In hospitals and in the community at large, this organism is increasingly identified as a pathogen. To develop a diagnostic test that combines the strengths of immunoassays (cost) and DNA amplification assays (sensitivity/specificity), we targeted a genetically stable PaLoc region, amplifying tcdB sequences and detecting them by hybridization capture. The assay employs a hot-start isothermal method coupled to a multiplexed chip-based readout, creating a manual assay that detects toxigenic C. difficile with high sensitivity and specificity within 1 h. Assay automation on an electromechanical instrument produced an analytical sensitivity of 10 CFU (95% probability of detection) of C. difficile in fecal samples, along with discrimination against other enteric bacteria. To verify automated assay function, 130 patient samples were tested: 31/32 positive samples (97% sensitive; 95% confidence interval [CI], 82 to 99%) and 98/98 negative samples (100% specific; 95% CI, 95 to 100%) were scored correctly. Large-scale clinical studies are now planned to determine clinical sensitivity and specificity. PMID:22675134

  17. Air heating approach for multilayer etching and roll-to-roll transfer of silicon nanowire arrays as SERS substrates for high sensitivity molecule detection.

    PubMed

    Wang, Yan; Zhang, Xiujuan; Gao, Peng; Shao, Zhibin; Zhang, Xiwei; Han, Yuanyan; Jie, Jiansheng

    2014-01-22

    SiNW array represents an attractive system for construction of high-performance energy, electronic, and sensor devices. To meet the demand for flexible devices as well as address the concern about the full use of the Si material, large-area transfer of the SiNW array from growth substrate is very desirable. Here, we report a simple air heating approach to achieve the multilayer etched SiNW array. This method allows the fabrication of up to a five-layer (while perfectly three-layer) cracked SiNW array on single-crystalline Si wafer via a templateless metal-assisted etching approach. Fractures could happen at the crack position when an appropriate pressure was applied on the SiNW array, facilitating the wafer-scale layer-by-layer transfer of the SiNW array onto a flexible substrate through a low-cost and time-efficient roll-to-roll (R2R) technique. Further releasing of the SiNW array to other receiving substrates was accomplished with the aid of a thermal release tape. After modification with sliver nanoparticles (AgNPs), the flexible SiNW array showed great potential as a high-sensitivity surface-enhanced Raman spectroscopy (SERS) substrate for detecting rhodamine 6G (R6G) molecule with concentration as low as 10(-9) M.

  18. Metallic nanocone array photonic substrate for high-uniformity surface deposition and optical detection of small molecules.

    PubMed

    Coppé, Jean-Philippe; Xu, Zhida; Chen, Yi; Liu, G Logan

    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 spotting beneficial

  19. Metallic nanocone array photonic substrate for high-uniformity surface deposition and optical detection of small molecules

    NASA Astrophysics Data System (ADS)

    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

  20. Efficacy of direct detection of pathogens in naturally infected mice by using a high-density PCR array.

    PubMed

    Henderson, Kenneth S; Perkins, Cheryl L; Havens, Richard B; Kelly, Mee-Jin E; Francis, Brian C; Dole, Vandana S; Shek, William R